EFFECTS OF WEATHER ON TACTICAL AIR OPERATIONS OVER NORTH VIETNAM AND LAOS

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Collection: 
Document Number (FOIA) /ESDN (CREST): 
CIA-RDP84-00825R000100090001-6
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RIPPUB
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S
Document Page Count: 
43
Document Creation Date: 
December 9, 2016
Document Release Date: 
February 22, 2001
Sequence Number: 
1
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Publication Date: 
April 1, 1966
Content Type: 
REPORT
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PDF icon CIA-RDP84-00825R000100090001-6.pdf2.76 MB
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Apprc vsc F? Rene e 2 iQ1d 8f 4 _ 8 p00i 25F300Q10~0 I- plil 1964 t t ! Is AR at f 4 *sg TR 'OF ~N"S ,~~ , ?~4`R,- T .. OV R. ,NCB. ".I?T Am, _ M D :,LAOS DIRECTORATE OF, INT,II~r Approved, For` Release 2001/08114 ":" ClA-RDP.84-0QO.25 0 00 -SECRET Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 This material contains information affecting the National Defense of the United States within the meaning of the espionage laws. Title 18, USC, Secs. 793 and 794, the trans- mission or revelation of which in any manner to an unauthorized person is prohibited by law. GROUP 1 EXCLUDED FROM AUTOMATIC DOWNGRADING AND DECLASSIFICATION Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 S-E-C-R-E-T FOREWORD This report, prepared in the Office of Basic Intelligence, describes and assesses seasonal weather conditions in North Vietnam and Laos and the effect of those conditions on tactical air operations. Tactical air operations, in this sense, include low-level aerial reconnaissance as well as low-level bombing and combat air support and supply. For the most part the report is not pertinent to high-altitude operations, nor is it suitable for use in support of specific air operations. Data used are derived from climatological observations made over a period of many years and, therefore, constitute averages. Individual weather conditions may vary suddenly and considerably from the norm. S-E-C-R-E-T Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 S-E-C-R-E-T EFFECTS OF WEATHER ON TACTICAL AIR OPERATIONS OVER NORTH VIETNAM AND LAOS Summary The monsoonal airflows that control weather conditions in Southeast Asia are strongly affected by terrain barriers such as the Chaine Annamitique that separates Laos from North Vietnam and South Vietnam. Different weather conditions, accordingly, prevail in different parts of Laos and North Vietnam. From mid-May to mid-September, low closely packed clouds sweep out of the southwest, dumping torrential rains and limiting air-to-ground visibility over Laos. Air-support operations may have to be curtailed during this period. Across the Chaine Annamitique in North Vietnam, conditions are only slightly better for tactical air operations. Cloud- iness still prevails and operational conditions are fair at best. From mid-October to mid-March, when prevailing winds are out of the northeast, the contrast in climatic conditions is more pronounced. Through- out Laos and in northwestern North Vietnam skies are frequently clear and tactical air operations can be planned with relatively little fear of interference from the elements. In the rest of North Vietnam, however, the crachin -- a low and continuous cloud cover accompanied by drizzly rain -- prevails during the latter part of the period and operations requiring air-to-ground visibility may not be possible for days at a time. In general, the most favorable periods for tactical air operations in the various regions of North Vietnam and Laos are mid-October to mid- March in Laos and northwestern North Vietnam; mid-September to mid-October in the rest of northern North Vietnam; and mid-March into August in southern North Vietnam. S-E-C-R-E-T Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 S- E-C-R- E-T I. General Climatic Background* North Vietnam and Laos have a tropical monsoon climate characterized by two major seasons -- that of the southwest monsoon, usually prevailing from mid-May to mid-September, and that of the northeast monsoon, usually prevailing from mid-October to mid-March. These major seasons are sepa- rated by two short transitional periods -- the autumn transition, from mid-September to mid-October, and the spring transition, from mid-March to mid-May. This seasonal alternation of wind direction controls almost every aspect of the weather, with marked local variations determined by the situation of mountain ranges, especially the Chaine Annamitique, which lies at right angles to both monsoonal airflows and which forms most of the border between North Vietnam and Laos. During the southwest monsoon, warm moist air sweeps in from the Indian Ocean, bringing frequent precipitation to the region. Much of this summer precipitation is intercepted by the southwest-facing slopes of the Chaine Annamitique. Rainfall is heaviest on the exposed mountain slopes in eastern Laos, but even the leeward coastal areas to the east receive some moisture. The northern part of North Vietnam receives considerable precipitation during the southwest monsoon from winds that after crossing the Chaine Annamitique turn northward and pick up moisture from the Gulf of Tonkin before flowing back in over the land. In contrast to the ocean-born southwest monsoon, the northeast mon- soon originates over central Asia and reaches the region after traversing the southern part of China. At this time of year, relatively dry condi- tions prevail over much of the region. The southern part of North Vietnam is an exception. This area receives heavy precipitation during autumn and early winter from the moisture accumulated as the northeast monsoon passes over the Gulf of Tonkin. Again, the C:haine Annamitique acts as a barrier to these moist winds but at this season receives most of the precipitation on its east-facing slopes. North Vietnam and Laos are tropical regions, and temperatures and humidities are high all year. A slightly cooler period is experienced in the north during the northeast monsoon season, but this is only a relative change from the sultriness of the other seasons. Temperatures are still high, and humidities are often very oppressive. Low temper- atures are experienced only in the higher mountains, where they may drop below freezing. II. Effects of Weather on Tactical Air Operations Weather conditions over most of North Vietnam and Laos limit the conduct of air operations throughout most of the year. No season experiences * For data on weather conditions in this area, see Tables 1 through 3. S-E-C-R-E-T Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 S-E-C-R-E-T long periods of clear weather. Cloudiness, low ceilings, fog, and generally poor air-to-ground visibility are the chief limiting factors. Other phe- nomena that adversely affect air operations are widespread thunderstorms and associated turbulence, typhoons, and a period of persistent low overcast with fog and drizzle that is known locally as the crachin (from the French word cracher, to spit). Of lesser significance are such conditions as icing and clear air turbulence. The most serious limitation is the prevalence of numerous low clouds and fog and the resultant low ceilings and poor air-to-ground visibility. Cloudiness prevails throughout the year in most of the region, with only moderate seasonal fluctuations. Diurnal variations in cloud cover are probably greater than seasonal variations, and, at certain hours of the day at any season, relatively clear conditions may exist over a target for a short time. In many cases, this is a definitely local condition, and the need for timely information on the current conditions of visibility over a specific target complicates operational planning. These spotty local conditions may also influence the selection of the route to and from a target. If time over the target is critical, the weather en route becomes a serious factor because it may make detours necessary. Poor visibility en route also makes it difficult to spot ground checkpoints needed for navigation. Fog and low ceilings are common and seriously limit low-level operations. It is hazardous to attempt to fly under low clouds because of the mountainous terrain. In general, visibility is much better at high altitudes than at low altitudes. Thunderstorms occur most frequently during the southwest monsoon season and in spring, commonly about midday. Most such storms are fairly short but extremely violent and must be skirted by aircraft in flight. Severe turbulence is experienced in and around thunderstorms, particularly during the spring transition season. Thunderstorms often may interfere with a mission either by obscuring a target or by necessitating long detours en route to or from the target area. Occasionally a typhoon may interfere with air operations for a few days. Such typhoons originate in the South China Sea and may strike the coast of North Vietnam at any time between July and late November but are most common in August, September, and October. The direct passage of a typhoon will force cessation of all air operations. Sometimes a typhoon that approaches but does not strike the coast of North Vietnam interferes with air operations. Although 18 typhoons reached the general area of North Vietnam in the period 19+7-56, only 5 were of typhoon intensity by the time they reached the coast. The typhoon season in the South China Sea extends from May into January, but by late November the track of typhoons usually is too far south to affect North Vietnam. S-E-C-R-E-T Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 The prolonged spell of crachin weather occurs in North Vietnam from about December through April. This period of light rain or dull and gloomy drizzle is accompanied by low stratus clouds, mist, and fog, although the total amount of precipitation usually is small. The crachin affects air operations seriously, especially operations below about 8,000 feet, because of its limiting effect on air-to-ground visibility, its widespread character, and its seasonal persistence. Once the crachin season begins, it dominates weather conditions in North Vietnam until well into the spring. Icing conditions and turbulence not associated with thunderstorms or other convective activity are not serious limiting factors for air operations in Laos and North Vietnam, but some upper-air turbulence may be expected. Aircraft icing may occur between 15,000 and 25,000 feet during the southwest monsoon season, when the air is laden with moisture, but it can be avoided by flying a few thousand feet higher or lower. Most of the turbulence experienced over the region is associated with thunder- storms and other convective activity. A. Region A -- Laos and the Highlands of Northwest North Vietnam* 1. Southwest Monsoon Season (Mid-May to Mid-September) This is a poor season for air operations -- the moisture- laden southwest monsoon brings much cloudiness to Laos. The land, which gradually rises eastward, presents an upslope to the southwesterly air- stream and, together with the normal processes of convection, causes a general lifting of the air. Conditions are poorest in the southern half of Laos, where the monsoonal flow of air has a tendency to pile up against the Chaine Annamitique and form dense masses of cumulus and cumulonimbus clouds. In the north the clouds are less dense because the originally wet winds have lost some of their moisture as they traveled long distances over the land. A normal daily pattern is one of scattered low clouds in the morning increasing to broken clouds or overcast by afternoon. By mid-afternoon it is very common to have towering cumulus or cumulonimbus clouds extending above 50,000 feet. After a nocturnal thunderstorm, clouds frequently dissipate by midmorning. Ceilings are low at this time of year and air-to-ground visibility is generally poor. During the early morning the ground frequently is obscured by fog. Scattered clouds begin to build up later in the morning and, although in many cases they do not constitute a normal ceiling of 60 percent or more of cloud cover, they are low. They restrict visibility and make flying difficult. Shower or thunderstorm activity later in the * Region A Laos and the Highlands of Northwest North Vietnam), Region B (Northern North Vietnam), and Region C (Southern North Vietnam) are shown on the accompanying map. Approved For Release 2db'1 O 1' 'ECWA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 S-E-C-R-E-T day would reduce the ceiling and make low-level flying very hazardous. Probably the best time of day for flying is between 0800 and 1000, after the fog has cleared and before shower activity has begun. Turbulence associated with the towering cumulus and cumulonimbus cloud formations is widespread and can be very severe in thunderstorms. Minimum turbulence occurs at night after 2200 and before daylight -- except during nocturnal thunderstorms, which are more serious than those during the day because they are more difficult to see from the air. 2. Autumn Transition Season (Mid-September to Mid-October) During this season, cloudiness decreases as the drier, cooler air from the northeast monsoon begins to enter Laos. There is.a marked decrease in the total amount of low-lying clouds and a corresponding increase in the frequency of clear days. Thunderstorm activity still occurs but not as often. Clouds continue to build up toward afternoon, except along the Mekong River where low clouds that have accumulated during the night tend to dissipate during the day. Air-to-ground vis- ibility is markedly better than in the southwest monsoon season. Morning fog is still very common, but clearer skies and higher ceilings provide much better visibility. It is possible that the mountainous terrain would provide enough identifying features above the fog for navigation checkpoints and that some missions could be carried out despite the restricted ground visibility. The best time of day for air operations is from 0800 to 1000, before the general cloud buildup of midafternoon. From 1700 until dark is generally another period of good air-to-ground visibility. 3. Northeast Monsoon Season (Mid-October to Mid-March) The northeast monsoon season is the best time of year for air operations. Skies are frequently clear and cloudiness is at its seasonal minimum, although there are considerable variations locally, especially in the south where moist air enters Laos through low passes in the Chaine Annamitique and the resultant cloudiness is somewhat heavier than in the rest of the country. Morning fog still occurs, especially in the deeply entrenched northern valleys where it is often so thick that as it lifts, layers of low clouds form. An afternoon buildup of cumulus clouds is common, but complete overcast even at this time of day is rare. Weather conditions are generally good, and air-to-ground visibility is at its best. Near the end of this season the smoke from brush fires sometimes interferes with air-to-ground visibility. - 5 - Approved For Release 2001/08Y14-:CCIA_-RD_TP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Ii. Spring Transition Season (Mid-March to Mid-May) Cloudiness increases gradually, and visibility becomes poorer as the spring season progresses. At times, cloud amounts increase rather abruptly, especially in association with thunderstorm activity. Thunder- storms are most violent at this time of year, and severe turbulence associated with them as well as widespread convective activity is common throughout the country. In late April and early May, the steadily increas- ing daily amounts of cloudiness are reflected by increased frequencies of low ceilings. Also early in the season, when it is relatively dry, air-to-ground visibility is hampered by smoke from brush and grass fires. The smoke and dust are generally dispersed as thunderstorm activity increases, wetting down the ground and clearing the atmosphere, but by this time cloudiness is building up to its summer seasonal peak. In general, conditions for flying are not as bad as during the summer southwest monsoon but are much poorer than during the winter northeast monsoon. B. Regions B and C -- Northern and Southern North Vietnam 1. Southwest Monsoon Season (Mid-May to Mid-September) The wet southwest monsoon brings much cloudiness to North Vietnam, and conditions for air operations during this season are poor in the north and only fair in the south. Cloudiness is most widespread in the north, where the mechanical uplifting of the air as it reaches the mountains combines with the normal convective processes to form large cumulus or cumulonimbus clouds. On the leeward side of the Chaine Annamitique south of Thanh Hoa the atmosphere becomes somewhat drier because of the downslope motion of the airstream after it has crossed the mountain barrier, and cloudiness is somewhat less than in the north. Air-to-ground visibility is not good during this season even though clouds are usually scattered. Fleecy clouds at low elevations commonly interfere with effective visibility for pilots. During the morning, cloud bases below 1,000 feet are common, but, as the day continues, low clouds tend to disappear and the cumulus cloud bases usually form at elevations of 2,000 to 3,000 feet. During the frequent midday thunder- storms, which are usually short, ceilings are considerably lower. Com- pletely clear afternoons over any part of North Vietnam are relatively rare during the southwest monsoon season. In general, the best time of day for an air operation during this season is from 0900 to 1100, at which time the morning fog has burned off and the midday buildup of clouds has not yet reached its peak. Conditions in the south are slightly better than in the north. Even at its worst in mid-afternoon, air-to-ground visibility is still frequently good in the south and definitely better than in the north. Visibility at night is generally good after midnight. Approved For Release 20 }-18798/%fZrA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 S-E-C-R-E-T Extensive low stratus clouds occur whenever a typhoon enters the Gulf of Tonkin and approaches within 100 miles of the coastline, and they reduce visibility considerably. During this season typhoons are most common from late July on, and the passage of a typhoon over the country would disrupt all air operations for a few days. 2. Autumn Transition Season (Mid-September to Mid-October) In autumn, conditions for air operations begin to improve in the north and deteriorate in the south. This is probably the best time of year for air operations in the northern part of the country, as there is a marked decrease in amounts of cloud cover. Conditions are poor in the southern part of the country, which is on the windward side of the Chaine Annamitique at this season and receives increasing amounts of precipitation with accompanying heavy clouds. In the north, low ceilings are slightly less frequent and air-to-ground visibilities are slightly better in autumn than during the preceding southwest monsoon season, mainly because there is less thunderstorm activity. In contrast, the conditions for air operations in the south have deteriorated from those of the southwest monsoon season. Afternoon convective activity combined with the orographic effects of the rising moist airmass from over the Gulf of Tonkin causes frequent showers, and as a result visi- bility is reduced. As in the southwest monsoon season, the best time of day for air operations probably is 0900 to 1100, but conditions are better in the north than in the south. In the north the period from about 1700 until darkness also offers good conditions for flying. This is the typhoon season and one of these storms may strike North Vietnam at any time, totally disrupting operations for a few days. 3. Northeast Monsoon Season (Mid-October to Mid-March) Although weather conditions become generally good in Laos during the northeast monsoon season, conditions for air operations in southern North Vietnam are poor. This is the cloudiest time of the year, as the frequency of cloud bases at low altitudes increases. Conditions in northern North Vietnam remain fair with generally favorable flying conditions until the advent of the crachin in January. The pattern of favorable conditions in the north and unfavorable conditions in the south changes about December to general unfavorability everywhere as the crachin approaches. This period of low persistent overcast with fog and drizzle and, few, if any, sunny days lasts through the remainder of the northeast monsoon season and into the spring. During the crachin, which is most widespread from January until early April, the persistent low clouds, drizzle, and poor air-to-ground visibilities frequently make air operations that depend on visual contact with the ground impossible. Skies are generally clear above 6,000 to 8,000 feet, but the land is obscured. In general, the crachin is a coastal condition S-E-C-R-E-T Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 and is restricted to the eastern lowland areas, although it does move up some of the gently sloping valleys and penetrates adjacent upland mountain areas. Breaks of clear weather during the crachin season are infrequent. In the southern part of North Vietnam the crachin is not as widespread or as well developed as in the north, and the chances of good weather for air operations are slightly better. 4. Spring Transition Season (Mid-March to Mid-May) During the early part of this season the crachin is still in evidence, but the forces that create and maintain it are rapidly weakening. Spring is a season of decreasing cloudiness and increasing thunderstorm activity. Conditions for air operations are generally favorable, at least in comparison with the preceding and succeeding seasons. They are much better than during the latter part of the northeast monsoon and at least as good as during the southwest monsoon of summer. Conditions in the south probably are at their best for the year. The best time of day for air operations probably is late morning, after the morning clouds have been burned off by the sun, which is almost directly overhead at this time of year. Thunderstorms are particularly violent at this season, and turbulence associated with them is severe. Approved For Release 208 M4 IA-RDP84-00825R000100090001-6 ,Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Laos and North Vietnam Generalized Seasonal Evaluation of Weather Conditions for Air Operations Southwest Monsoon (Mid May to Mid-Sep) Autumn Transition (Mid-Sep to Mid-Oct) Northeast Monsoon (Mid-Oct to Mid Mar) Spring Transition (Mid-Mar to Mid May) Region A Laos and Highlands Region B Region C of Northwest North Vietnam Northern North Vietnam Southern North Vietnam Fair Fair Fair a/ Good 1 Fair (Mid-Oct to Dec) Poor (Dec to Mid Mar) Fair to Poor Fair to Poor a. Best season for air operations. Approved For Release 20O1 9%. tt-RDP84-00825R000100090001-6 Fair 1 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Table 2 Xeos an:. _oort1i Vie t:ai,: can ~10uciness Station man Feb ':ar ' Hanoi 77 84 87 82 Ldo Kay 85 83 77 71 `ion Cay 77 87 87 83 Nam Dinh 82 86 go 31 Dong Hoi 78 78 77 Vinh 34 87 84 74" Luang Pracang 53 34 32 36 Pakse 40 39 45 60 Thakhek 19 32 37 .,entiane 3! 39 35 a J n Jul "a Ser. Oct O Nov c 75 78 78 77 68 6o 67 68 68 73 74 71 68 73 76 75 75 7; 76 74 65 56 60 65 73 71,' 79 70 73 61 66 68 - 66 73 a, 71 73 73 74 77 76 33 83 51 59 69 69 54 47 50 52 73 32 38 36 36 68 61 48 71 31 31~ 14 76 48 33 25 48 73 3_ 98 34 73 51 39 Approved For Release 2001 /08tL :.J? RDP84-00825R000100090001-6 , Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 North Vietnam Mean and Maximum Number of Days with Crachin Weather Feb Mar Apr May Jun Jul Aug SL Oct Nov Dec Hanoi Mean 11 12 19 13 1 _/ 0 a/ 0 1 3 8 Max 18 20 23 20 3 1 0 0 3 9 17 Mon Cay Mean 11 12 16 12 a 0 0 0 0 1 5 8 Max 16 18 25 19 1 0 0 0 0 2 13 21 Nam Dinh Mean 10 13 19 12 1 0 0 0 a 1 5 8 Max 15 18 27 18 3 0 0 0 2 3 10 16 Dong Hoi Mean 9 9 10 4 0 0 0 0 0 1 7 8 Max 17 18 16 9 0 0 0 0 0 1 14 17 Approved For Release 2001/08/1 - -- DPI-00825R000100090001-6 100 \o-chin eng z 108 04 P'u-erh `J Nan-nin f fzrtf C NA r! $3L1 Yu-lin N O x ~ C H I N A 2 2, 2; lo TuSte i S`o Quan one Tu 1 ;7 __ Thai N M BUR D n N A Afi o'Mong i_ n I Gei_ f B e n r ie s n ~` P7ru n Qng) uorrg Item The ~ 4 ._ oc aiph nglj ? ou ai _ Sa a l ~ mneua? s n H a hank ~^n uan 1Vek Luang C iang rabang ai Hoa ( ^ G GI% g-Seri- PhOU_ Kin ) I" -so Muang NKIN HAINAN Nan Vin Pak Sane H ng-Iii IE TIAN 0-ling N K h i * ong a ~MII aa Nakh nn on Dong Hoi Phhano ha o ane Muang Phitsanulok an \ emarc on line S' Sepon -> 0 Qua ng Mon Kaen annakhetIUe T H A I L A N D D91 Nang an 01 Muang Nakhon Sawan Ubng Nakhon ak e Ratchasima arln Chamrap Attope ti Prachin Buri BANG OK eiku An NAT; Chachoengsao Siso ~- on to eng , LAOS - NORTH VIETNAM M B D I A- T ' 1 SAI Ban MM ` rnfi Prevailing Surface Airflow Kratie Tht > Southwest monsoon 9 / Mekz>n r? aa~ Northeast monsoon : . Region boundary , HNO U 7 l * EN E E T Generalized Seasonal Evaluation i of Weather Conditions, by Region 7 Phan Thiet -~ AIGON SEASON A B C SW MONSOON Poor Poor Fair on MYT o AUTUMN Fair Fair* Poor Xuyen ) Vung Tau NE MONSOON Good* (to Dec) Poor i Sa c Fa r (after Dec) Poor DAD HU QUOC Can m)'y . Tho (ietn SPRING Fair to Poor Fair to Poor Fair* ~ Vinh *Best season Loi 0 u0 uu uu MIIes Quhn / - 0 50 100 150Kilometers CON SON I P 0 NAMES AND BOUNDARY REPRESENTATION ARE NOT NECESSARILY AUTHORITATIVE Approved For Release 2001/0N4RIifDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R00010009000~1-6 SECRET Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 20 April 1966 Distribution List for CIA/BI GM 66-3, Effects of Weather on Tactical Air Operations Over North Vietnam and Laos Only (Destroy this List after Distribution is made) EXTERNAL DISTRIBUTION No. of Copies Recipient Defense Intelligence Agency DIAAQ-3 Building A Arlington Hall Station Assistant Secretary of Defense, ISA Room 4D825 Pentagon 1 - Edward Van Sant Office of Foreign Economic Affairs Department of Defense Director of Defense Research and Engineering Room 3D139 Pentagon Department of State Director of Intelligence and Research Room 6531 State Department Building Department of State INR Communications Center Room 6527 State Department Building National Indications Center Room 1E821 Pentagon NSA (via GB-31 Hqrs.) STATINTL National Security Council Information Liaison Room 369 Executive Office Building National War College Fort Lesley J. McNair Classified Recrods Section USIA, IRS/A, Room 1002, 1750 Pennsylvania Avenue, N.W. Attn: Warren Phelps DIASA-2C, Room 2D233 Pentagon Attn: Chief Jonas DIAXX, Room 1+A1088 Pentagon Lt. Gen. A. J. Goodpaster, Jr. Assistant to the Chairman Joint Chiefs of Staff Department of Defense Room 2E873 Pentagon Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 INTERNAL DISTRIBUTION No. of Copies Recipient DDI/CGS/HR/Ops, Room 1-G-81 Hqs. DDI/CGS/SIGINT/Guide, Room 6-G-28 Hqs. D/OBI, Room 1002, Magazine Building OCR/BR, Room 1-H-61+ Hqs. OCR/DD/AB/IPI, Room GE-47 Hqs. OCR/GR, Room 1-E-1+810 Hqs. FIB/SR/CR, Room 1-G-27 Hqs. OCR/LY/DOC, Room 1-H-1107 Hcjs. D/OCI, Room 7-G-15 Hqs. DONE, Room 7-E-1+7 Hqs. Oper. Center, Room 7-F-33 Hqs. DCS/SD, Room 811 Key Building OCR/FDD, Room 1+15 Key Building D/OSI, Room 6-F-1+0 Hqs. STATINTL NPIC/CSD/REF, Room 1S518, 1-B-1+021+ Hqs. DDI/CGS/HR/T, Room 3-E-56 Hqs. DDS&T/OSA, Room 6-B-1+0 Hqs. OS/SRD/CAB, Room GE-31 Hqs. OTR/IS/IP, Room 532, 1000 Glebe VMR, A-18 ORR, Room GH-0915 Hqs. OCR/DD/Standard Distribution COS, Saigon Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001J08/14~ CIA-RDP84-00825R000100090001-6 Distribution List for CIA/BI GM 66-3, Effects of Weather on Tactical Air Operations Over North Vietnam and Laos Only (Destroy this List after Distribution is made) EXTERNAL DISTRIBUTION No. of Copies 17 Recipient Defense Intelligence Agency DIASQ-3 Building A. Arlington Hall Station Assistant Secretary of Defense, ISA Room 1tD825 Pentagon 1 - Edward Van Sant Office of Foreign Economic Affairs Department of Defense, 3a~ two= Director of Defense Research and Engineering Room 3D139 Pentagon Department of State Director of Intelligence and Research Room 6531. State Department Building Department of State INR Communications Center Room 6527, State Department Building National Indications Center Room 1E821. Pentagon NSA - (via GB31 Hqrs.) STATINTL National Security Council Information Liaison Room 369 Executive Office Building National War College Ft. Lesley J. McNair, Classfied Records Section USIA, IRS/A, Room 1002, 1750 Pe msylvania Ave.,NW Attn: Warren Phelps DIASA-2C, Room 2D233 Pentagon Attn: Chief Jonas DIAXX, Room )4A1088, Pentagon Lt. Gen. A. J. Goodpaster, Jr. Assistant to the Chairman Joint Chiefs of Staff Department of Defense Room 2E873, Pentagon Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA?RDP84-00825R000100b9000'I-6 k D .st ribt ion ist f?r CIA/$I GM. 66-3, E'fectpo Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2061/08/14: CIA-RDP84-00825R000100090001-6 INTERNAL DISTRIBUTION Recipient DDI/CGS/SIR/Ops, Room 1G81 Hgrs. DDI/CGS/SIGINT/Guide, Room 6G28 D/OBI, 1002 Magazine Building OCR/BR, Room 1H64 Hqrs. OC R/DD/AB/IPI, Room GE47. Hq~s. OCR/GR, Room lE4810 Hors. FIB/SR/CR, Room 1G27 Hqrs. OCR/LY/DOC, Room 1H1107 Hqrs. 0/OCI, Room 7G15,Hgrs. D/ONE, Room 7E47 Hgrs. Oper.Center, Room 7F33 Hqrs. DCS/SD, 811 Key Building OCR/FDD, Room 415 Key Building D/OSI, Room 6F40 Hgrs. NPIC/CSD/REF, Room 15518, 1B4004 Hqrs. DDI/CGS/HR/T, Room 3E56 Hqrs. DDS&T /OSA, Room 6B40 Hqrs. OS/SRD/CAB, Room GE31, Hqrs 0TR/IS/IP, Room 532, 1000 Glebe VMR, A-18 Office of Research and Reports, OCR/DD/Standard Distribution Room GH 0907 Hqrs. 350 Hqr, 2 Director 1 CD/BI 2 ED/BI 5 GD/BI 2 NLD/BI 2 PD BI Room GH0915 Hqrs. Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Standard Form 63 Novombor 1961 GSA FPMR (41 CFR) 101-11.6 MEMORANDUM OF CALL ^ RETURNING YOUR CALL 0 IS REFERRED TO YOU By: 'LEASE CALL LEFT THIS MESSAGE: U.B. GOVERNMENT FAINTING OFFICE ; IYI5 OF-755_153_Ip=- Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 ,Approved For Release 2001/08/14 : 9,10 "Approved For Release,2, 001/08/14: CIA_RDP84-00825R000100090001-6 THE SITUATION IN SOUTH VIETNAM SECRET WEEKLY Recipient Special Asst. to the President for National Security Affairs The White House The Vice President The White House Lt..Col. Richard Bowman Military Asst. to Special Asst. to the President for National Security Affairs Via: Information and Liaison Staff, NSC Room 365, 3;xecuti.ve Office Bldg. Deleted ]4 April 1966 St(~3ex,~r~~X~c The Hon. Dean S. Rusk- Secretary"of State Mr. Averell Harriman Ambassador -at -Large Department of State Ambassador Leonard Unger Special Asst. for Vietnamese Affairs Department of State Mr. Thomas L. Hughes Director, Intelligence-and Research Department of State Mr. William P. Bundy Asst. Secretary for Far Eastern Affairs Department of State Mr. Samuel D. Berger Deputy Asst. Secretary for Far Eastern Affairs Department of State Approved For Release 2001/0,8/14:4-00825R000100090001-6 i o For F2eleas '.200-1108/14.; GJA-RDP84.0082 9060.100090001-6 Mr. William C. Trueheart Director, office of'Southeast Asian Affairs Bureau of Far Eastern Affairs. Department of State Mr. David C. Cuthell Director, Office of Southwest Pacific Affairs Bureau of Far Eastern Affairs Department of State Mr. Robert W. Barnett Deputy Asst. Secretary for. Far Eastern Economic Affairs Bureau of Far Eastern Affairs Department of State Miss Ruth Bacon Office of Regional Affairs Bureau of Far Eastern Affairs Department of State Mr. Robert A. Fearey Director, Office of East Asian Affairs Bureau of Far Eastern Affairs Department of State Mr. Harold U. Jacobson Director, Office of Asian Communist . , Affairs Bureau of Far Eastern Affairs Department of State Mr. Richard L. Steider Public Affairs Adviser Bureau of Far Eastern Affairs (Department of State Mr. Robert H. Miller Director, Vietnam Working Group Bureau of Far Eastern Affairs Department of State 'Mr. Henry B. Cushing Assistant to Deputy Director for Lepartment of State Approved For Release 2001/0.8/1A:ZJA-:I P84-00825R000100090001-6 Mr. Jeffrey C. Kitchen Deputy Assistant Secretary Politico-Military Affairs Deputy Under Secretary for Political Affairs Department of State Mr. George A. Furness, Jr. Office of Research and Analysis for Far East Bureau of Intelligence and Research Room 7421 Department of State. Mr. Donald Q. Coster O/FSI/IS Room 109 State Annex - 3/W Mr. Walt W. Rostov Counselor of the Department and Chairman of the Policy. Planning Council Room 7261 Department of State Mr. Robert H. Johnson Policy Planning Council Room 7517 A Department of State Mr. Joseph J. Fisco Assistant Secretary .Bureau of International Organizations. Affairs Room 6323 Department of State Mr. Bruce M. Lancaster Director, Operations Center Room 7516, Department of State Mr. Llewellyn E. Thompson Ambassador-at -Large Room 7207 Department of State Mr. John E. Merriam Secretariat Staff, Executive Secretariat Room 5239 C Department of State -.Approved. For Release 20b1/0& 'P4- CIA-RDP84-00825R000.100090O01-6 Deputy-Asst. Secretary of'State Public Affairs Room 6804 A Department of State" 'Mr. Mr . Paul M. ICatte nbur 'Office of Southwest Pacific Affairs Bureau of Far Eastern Affairs Department of State Mr. George Aldrich Asst. Legal Adviser` Far Eastern Affairs, Room 6420 Department of State Mr. David E. Bell Director, Agency for Development Mr. Walter Stoneman Deputy Assistant Administrator East AID Room 6212, Department of State Mr. William S. Mazzocco Director, Office of. Vietnam Affairs.' AID Room 3317, Department of State Mr. Curtis Farrar Director, Office of Southeast Asian Affairs AID, Room 5212 Department of State The Hon. Robert S. McNamara Secretary of Defense The Ron. Cyrus R. Vance Deputy Secretary of Defense The Hon. John T. McNaughton Assistant Secretary of Defense (International Security Affairs) Office of Secretary of Defense orRelea~~e\2001108/14 CIA-RDP84-008 5 OQ h0009 rS..-..~ Sd~n ~ Approved For? Release 2001/08/14: O4A RD 00825R000100090001-6 Approved For Release 2001/08/14 : t1ARDP84-00825R000100090001-6 Mr.-Peter Solbert Deputy Assistant Secretary (International Security Affairs) Office of Secretary of Defense The Hon. Alain Enthoven Assistant Secretary of Defense for Systems Analysis Office of Secretary of Defense Rear Adm. Francis J. Blouin Far East Region Director , (International Security Affairs) Office of Secretary of Defense Capt. V. G. Hoizappel, USN Acting Chief, Coordinating Division Policy Planning Staff. (International Security Affairs) Office of Secretary of Defense OSD Cable Office of Secretary of Defense Lt. Gen. Joseph F. Carroll Director, Defense Intelligence Agency Via: DIASA-2C, Room 2 D 233,.Pentagon Maj. Gen. Robert Taylor Defense Intelligence Agency Via: DIASA-2C, Room 2 D 233, Pentagon. PROM DIAAP-2C, Room Via.: DIASA-2C, Room 2 D 233, Pentagon Chief, Yankee Team Task Force DIAXX-3, Room I D 918 Via: DIASA-2C, Room 2 D 233, Pentagon. Major Gen. John J. Davis Assistant Chief of Staff for.Intel, ligence Department of Army Via: DIASA-2C, Room 2 D 233, Pentagon' Brig. Gen. Jack E. Thomas Assistant Chief of Staff, Intelligence United States Air Force Via: DIASA-2C, Room.2 D 233, Pentagon . Approved For Release 2001/08/14"`'ClA-RDP84-00825R00010b090001.-6 A t1l f~ ~~ ~~ ~l Approved For Release 2001/08/14t,.ClA RED~P84-00825R000100090001-6 Rear Admiral Rufus L. Taylor'' Assistant Chief of Naval Operations (Intelligence) Department of Navy Via: DIASA-2C, Room 2 D.233,'Pentagon Colonel It. C. Berkeley United States Marine Corps Via: DIASA-2C, Room 2 D 233, Pentagon. Major Robert Rolf Intelligence Support Facility, USASSD Via: DIASA-2C, Room 2 D 233,.Pentagon Rear Adm. W. F. A. Wendt Director, Strategic Plans Division Room 4 E 566 Via: DIASA-2C, Room .2 D 233, Pentagon Rear Ada. Walter F. Schlech, Jr. Director, Politico-Military Policy Div. Room 4 E 572 Via: DIASA-2C, Room 2 D 233, Pentagon Lt. Gen. V. P. Mock Deputy Chief of Staff for Military Operations Room 3 E 648 Via: DIASA-2C, Room 2 D 233, Pentagon Eastern Division, Intelligence Support and Indications Center Defense Intelligence Agency Via: DIASA-2C, Room 2 D 233,'Pentagon Gen.. Earle G. Wheeler Chairman Joint Chiefs of Staff Maj. Gen.. William R. Peers . Joint Chiefs of Staff (SA.CSA) Room I E 962,, Pentagon Lt. Gen. David.A. Burchinal Director., Joint Staff ,Joint Chiefs of. Staff `Ma j;. Gen.. :Ashton -5 .. Manh.Vt Secretary,, ,Jo.int Chiefs ,of .;Staff For Release; 2,001/08/1 +??lA-RDP84-00825R000100090001-6 Approved For Release 2001/08/141A-R.LP84-00825R000100090001-6 Col. John B. Kidd Chief of Pacific Division,, Joint Chiefs of Staff Room 2 B 920, Pentagon Mr. Dichran Y. Hovsepian Chief, Geographic Branch Mapping and Geodesy Division Office of Chief of Engineers Room 1336, Bldg. 77, Gravely Point Via: DIASA-2C, Room 2 D 233, Pentagon Lt. Gen. Marshall S. Carter Director, National Security Agency Fort George G. Meade, Maryland Via: CIA Liaison Staff Mr. Howard C. Brown, Jr.. Assistant General Manager istration Atomic Energy Commission Germantown, Maryland Mr. William C. Sullivan Assistant to the Director Federal Bureau of Investigation Room 1018, 315 9th St.,'N.W. xrector, 1 E 821, Pentagon EYES ONLY - PERSONAL CIA Representative National Military Command Center Room 2 D 901A, Pentagon DCI DDCI EXECUTIVE DIRECTOR Approved'For 'Release.2001'/08/14: CIA-RDP84-Q085}OO0100090001-6 ~1 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 25)1A 87'62 net ~.tPd 4[8]6.6 '25XiA, 25X1A 25XIA --llar~ ~i-sr Western- Hemisphere- -: iv. 25X:1 A. ,25X1A. .--MH/C-GS PjDDP-r _ I I nnm riG..27O8 i grs-..,,:.$J.dgw 5&,._}I&j - Bldg. 6 Approved For Release 2001./08/14: CIA-RDP 4-00825800010009.0001-6 Room. 5 D 3123, Hdgrs.? Bldg. Room 4 D 14, Hdqrs... Bldg. Room 4 D 01119 Hdqrs. Bldg. Approved For Release 2001/08/14 A:FibP84-00825R000100090001-6 25X1A. Rv?m y, mat . : B~:dg. 119--121 Special Asst-for Vietnamese Affairs Eff. 4/5/66 25X1A COMUS MACV Via: DIASA-2C ATTN: oom 2 D 233, Pentagon Colonel Patterson 25X1A CINCPAC J-2 Via: DIASA-2C ATTN: Room 2 D 233, Pen agon 11 Ambassador Elbridge Durbrow Air War College Maxwell Air Force Base, Alabama Via: INR Communications Center Room 6527, Dept. of State Approved For Release 2001/08/L4)_CIA-RDP84-00825R000100090001-6 25X1A Mr. Melvin L. Manfull American Embassy, Saigon Via: INR Communications.Center ATTN: Mr. S. Solomonson Room 6527, Department of State (DO/II will forward) Mr. Robert H. Miller Eff. 25 March 1961 Director, Vietnam Working Group Bureau of Far Eastern Affairs Department of State Mr. Robert T. Burke 3/29/66 State Department Advisor Ft. Bragg, North Carolina VIA: INR Communioatfbpus Center Room 6527 Department of State Mr. Robert K. German 4/13/66 Bureau of Intelligence and Research:.:. Office of Research and Analysis for Soviet Bloc Room 7422, Department of. State AUL (AUL3T-66-D3) Maxwell AFB, Ala. 36112 VIA: DIASA-2C ATTN: Approved For Release 200110a144: CIA-RDP84-00825R000100090001-6, Approved For Release 2001/0$/'1T:"d RDP84-00825R000100090001-6. Approved Felease 2001/08/14: CIA-RDP84-008000100090001-6 DISTRIBUTION LIST TITLE OF REPORT DATE REPORT NO. / _ '31 PROJECT NO. 1 CLASSIFICATION CONTROL NAME OF REQUESTER NAME OF ANAL YST BRANCH GRAPHICS RECIPIENT DATE SENT 4 ,r. IF STATINTL STATINTL B S -t- ~~ L.7 STATINTL 6E R 19 ~-`- 7 FORM 12.64 2362 Approved For~Release 2001/08/1tCgcp84-00828 00100090001-6 Effect of Weather on Air Opr. in Laos and North Vietnam pN 61.2286 Revi6es GB 65-17) DD/I Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 &M:66-3 Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 GM 66-3 GM 66-3 is not to be disseminated., on order from DD/I and D/OBI. For earlier study, see GB 65-17? Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 Approved F Release 2001/08/14: CIA-RDP84-008 58000100090001-6 NOW, GM 66-3 20 April 196b Report ready for dissemination. 10 copies picked up from PSB. Brammell said to hold. Apparently DD/I wants to know changes made that make this report different from the earlier one: Changes in one paragraph, 1 additional footnote; the foreword, and the summary -- GRW says. 22 April 1966 Report to be held and not disseminated, so says Bramwell. All copies (except above 10 mentioned) to be sent here by PSD. Approved For Release 2001/08/14: CIA-RDP84-00825R000100090001-6 12Apr66 ]J Apr66 ~s'GL 22Apr66 PROJECT PROPOSAL Written; re rc is eaovrFc(ru~~le eBO~(~ : CIA- typing today. STATINTL Bramwell told that Smith does not wan is released (report not materially changed from the former one); all copies to be sent here. :DP84-00825R00 00 90001-6 /3 '7) Approved For Release 2001/08/14: CIA. 61.22_$6 _Effcot of Weather/Air Opr.,Laos,No.Vietnaii DD/I ?roVect N70. Fe a e t r 61, DeadlAna 'or Deliv ry to. the Requester -/-" ra ch Cie ~,, 3pse1al -A-sat, p,.~- r- Division ief R ?' r- Ldi tLn Rev ,ew Editor Approved For Rek5- ": k k aly,3t S~ Q! 4-8 2 '90100090001-6 E3itor/yat Typist (final) Proofreaders -nralyst For Ditto 03s Bond with Other Viler lnatruc: ti Gns cad Cr taai; is +,rC33?p' 3~R? g.C::, Sran 't Final Editorial Approval Before Reprod wtl oa and Distribution ADMMS t S w lh .L ti OI Le+si,oatfcs4