330 MONTHLY WEATHER REVIEW OCTOBER 1938 Date -- 1938 Oct.31.-.. POSITIONS AND AREAS OF SUN SPOTS-Continued East- ern stand- ard time h nr 11 12 Date nrt.. :ilson ,roup No. 6166 6160 6185 6156 6154 615s 6171 fiirjs 6lf4 616i 6163 6166 6165 6lSS Ri(io 6156 6154 616s 6175 6171 GI64 6174 61iO 616’: Rli3 6169 61R6 6163 6160 6 1 2 6155 6156 6177 6176 6175 6171 6168 6164 6167 6173 6169 61R3 f166 6172 til56 6154 ~1 5 4 6ifin 6177 6176 6175 6 l i l 6168 61fi4 6179 filfi7 6173 6169 813 6163 GI66 6160 6172 8156 190s Oct. 26.- Oct. 27. - Oct. 3.. o c t . 29-- Oct. 30 ... - in longi, tude -- 4 .0 -3.0 +Y.5 f13.O +30.0 -I-61.C -73.a -1j4.0 -53.0 -17.0 +5.0 +5.0 +S.(s +21.@ +i i .a +26.a +~i .a -5n.0 -79.0 -W.O -40.5 -2?.O -6.5 -6.0 -4.0 -2.0 f19.0 +?O.O +%. fl +27.0 i-35.D +39.0 -78.0 -73.0 -63.0 -45.0 -37.0 -26.6 +9.5 +10.0 f12.0 4-34.0 f34.0 +41.5 +51.0 fi0.0 +56.a +4i.o -65.0 -61.0 4 3 .0 -35.0 -?5.0 -15.0 +6.0 +23.0 f23.0 +24.0 +35.0 +45.0 i-49.0 f53.U +58.v +64.0 East- ern itand- ard time a r t . iilson :roup No. h .m 12 n 11 14 11 4 14 21 11 33 ~ pie. longi- tude In -- I Heliographic 170 35s 73 194 97 12 ._.---_ 20 ....__. 2s _..___. 9 .._____ 9 ______. 2 1.2i3 1 - Longi- tude 6180 f i l i i 6176 0175 6131 (*) 616s 61b4 61i3 GIB3 GIGO c i l R I I 6158 0 102.5 107.5 120.0 123. 5 140.5 l i 3 .5 2s. 0 34.0 45.0 PI. 0 103.0 lac. 0 109.0 119.0 124.0 13Y. 0 5.9 24. 9 34.9 44.4 82.9 i6.4 i5.9 s@. 9 S?. 9 103.9 104.9 109.9 111.9 119.9 123.9 140. Y 351.9 356.9 6.9 24.9 32.9 43.4 79.4 79.9 81.9 103.9 110.9 111.4 120. 9 139.9 353.2 35i. 2 5.2 23.2 33.2 43.2 64.2 81.2 81.2 62.2 83. 2 103.2 107.2 111.2 111.2 122.2 ins. o 103.9 -64.0 --8?.(I -31.0 -39.0 -24.0 -1G.CJ -11.0 -1.0 +37.0 f58.0 f63.0 +%.a fiS.0 - Lati- tude - -11.0 -15.0 f13.0 f25.0 -11.0 fll. 5 +9. 0 +?a. 0 f15.0 -31.0 -25.0 -11.0 -19.0 -15.0 f l ?. 0 f25.0 -11.0 f18.0 t10.0 +26. 0 f14.0 -15.0 -12.0 -32.0 t13.0 +9.0 -11.0 -22.0 -15.0 -2.0 f13.0 f25.0 -11.0 f l l .O -9.0 fli. 0 +lo. 0 f26.0 f14.0 -31.5 f15.0 +e. 5 -2 2 .5 -11.0 -14.0 -3.0 f27.0 -11.0 f l l .0 -9.0 f19.0 +io. n 4-26.0 4-15.0 f16.0 -30.5 +le. 0 f9. 5 fli. 0 -23.0 -11.0 -13.5 -3.0 tn. 0 21.2 29.2 34.2 44.2 8 3 .2 103. 2 110.2 133.3 108.2 Area -12.n +14.0 f24.5 f14.5 +15.0 -23. 0 -1i.n -13.0 +2T.O ~__ I I- 6 6 315 121 121 315 48 3% 194 .______ 4 .__.._. 1 ._____. 39 _______ 2 .__._.. 3 .______ 14 ._____. 1 .-..... 12 1,950 3 12 133 IS? 24 46 242 12 3% 4s 315 73 36 73 242 109 12 61 12 12 4s 194 109 388 6 46 291 4s 145 242 e1 12 291 121 24 97 61 194 145 3% 24 121 8 145 218 121 12 291 121 8 12 S i 24 6 315 97 485 24 194 Observatory U . S. Nnval Do. Aft. Wilson. U. S. Naval. Do. ._--.-_ 2 _______ 5 ._.-.-_ 2 ._.._._ 4 ..__.__ 10 .._____ 8 .._____ 2 .._____ 20 _._____ 6 ..___._ 12 1,477 3 ._____. 3 _______ 13 ..____. u) ..____. 2 .._._._ 5 .._____ 12 _._____ 2 _______ ? _____._ 13 .______ 16 .___.__ 12 .______ 40 .______ 1 ._____. 6 ..__... 18 1,669 3 _______ 2 _____._ 4 _____._ 3 _______ 1 ______. 23 _______ 1 _._.___ 2 _._____ 2 _______ 6 ___._._ 16 _____._ 10 .______ 15 .______ 1 -.-.... 6 1,933 1 .______ 4 ____--- 4 ___---- 8 _______ 2 _______ 16 ._----. 4 ___--.- 1 _______ 1 .______ 7 ___---- 4 _______ 1 __-____ 23 .____-. 4 .._____ 28 ..___._ 4 2,168 2 POSITIONS AND AREAS OF SUN SPOTSContinued I Observatory U. S. Naval. Mean daily area for 30 days--1.951. ‘Not numbered. PROVISIONAL SUNSPOT RELATIVE NUMBERS FOR OCTOBER 1938 [Dependent alone on obserrntlons at Zurich, Switzerland] [Data furnished through the courtesy of Prof. W. Brunner, Eidgen. Sternuwte, Zurich, Switzerland] Octoher 1 Relatire /I Ortoher I Relative 1836 numbers // 1935 numbers 1938 numbers October Rela t i r e 16 _______ 78 17 _______ Afc71 18 _______ d 31 I I 31 _______ 1 a 155 II Mean. 24 davs=93.5. October 17.’ Middle large bright chromospheric eruption at O h 43* to gh 59“ U. T., W. a=Pns;soge of an average-sized g o u p through the centrsl meridian. b= Passage of a liarze ?roup or spot throuzh the central meridian. c=New formation of n group developing into B middle-sized or large center of activity: E, nu the east.ern part of the sun’s disk; W, on the western part; M, in the central circle zone. d=Entrance of a large or average-sized canter of activity on the east limb. AEROLOGICAL OBSERVATIONS [Aerological Division, D. hl. LITTLE In charge] By B. FRANCIS DASHIELL During October 1938 a total of 523 aerological observa- tions were macle by airplane and radiosonde a t 18 points in the tTnited States. The mean free-nir data based on these observations are gken in tables 1 and la. They include the basic meteorological elements of pressure, .temperature, and relative humidity, recorded a t certain geometric heights. At four stations a niasinium height of 31 kilon!e- ters was reached during 3 1 racliosonde observations, wliile all of the 309 observations listed in table la reached a height, of 16 kilometers. The “means” are omitted whenever less than 15 observa- tions nre made a t the surface and less than 5 a t a standard height, but 15 observations are required for those levels that come within the upper and lower limits of the nionthly vertical range of the tropopause. A brief descrip- tion of the met,hods used for computing these means will be found under “Aerological Observations” in the January 1935 issue of the MONTHLY WEATHER REVIEW. The month of October was abnormally warm, as shown by chart 1. The mean swjace temperatures (O F .) were above nornial throughont the entire United States, with only minor exceptions along the south Atlantic coast, and in Florida and portions of California. East of the Missis- sippi River and west of the Rocky Mountains, the depar- tures of mean surface temperature above the normal were moderate, but in the central States and upper Missouri valley the mean temperatures were in excess by as much as loo F. above the normal. These positive MONTHLY WEATHER REVIEW 33 1 departur?s ,in October showed a continuance of the ten- dency existing throughout the summer and fall months of 1938 for the surface temperature to range considerably above the noraal. Mean free-air temperatures (" C.) recorded abow tlie surface over the United States cluring October a t all sta- tions were seasonally lower than those noted in the preced- ing month of September, except over Sault Ste. Marie, Mich., a t 3 kilometers. The highest mean temperatures were confined generally to the southern half of the country, but a warm area pushed northward as far as Omaha, Nebr. The highest October nieans for the countiy, as recorded a t each level, were noted over Pensacoh, Fla. (18.2' C.); Oklahoma City, Okla. (18.3' C.); El Paso, Tes. (18.3' C., 15.4' C., 11.9' C., and 8.1' C.); and over Pensa- cola, Fl?. (0.2' C. and -5.S°C.)*at 0.5, 1, 1.6, 2, 2.6, 3 ,4 , and 5 kilometers, respectively. +he lowest mean temper- tures of 6.8' C., 6.0' C., 6.2' C., 2.9' C., 1.9' C., -6.0' C., and -12.4' C., occurred o ~e r Saiilt Ste. Marie, Mich., a t 0.5, 1, 1.5, 2, 2.5,4, and 6 kilometers, respectively, while the lowest a t 3 kilometers (-0.1' C.) was reported over Seattle, Wash. Mean temperatures were decidedly lower during the current month a t all levels over Seattle arid Spokane, Wash., than those recorded in September when the same two stations reported exceptionally warm means a t all levels. Over Spokane, Wash., the mean temperatures in October were lower than in September by 10.0' C., 9.5' C., 8.5' c., 7.2' c., 6.0' c ., 4.3' e., and 3.4' c., at 1, 1.5, 2* 2.5, 3, 4, and 5 kilometers, respectively. However, vver Sault Ste. Marie, htich., Chicago, Ill., Nashville, Tenn., and Omaha, Nebr., the mean temperatures for October a t each level were only slightly lower than those recorded in the preceding month of September. In the high altitudes above 5 kilometers, where records were obtained only by radiosonde, the lowest mean temper- ature for the United States was -65.2' C., over Oklahonia City, Okla., a t 17 kilometers. Slightly higher mean mini- mum temperatures (-60.6' C . and -6214' C.) were re- corded farther north over Sault Ste. Marie, Mich., and Fargo, N. Dak. All of the lowest mean temperatures for all stations were recorded along the 17-kilometer level as was also the case during the preceding month of Septem- ber. A gradual increase in the mean temperature occurred upward above 17 kilometers, to as much as -60.4' C'. over Oklahoma City, Okla., a t 21 Iiilometers. This was the lowest recorded a t the highest altitude reached in October. However, temperatures for the current month were sliglitIy higher in the high altitudes than those recorded during September a t correspoiiding levels. Isobaric charts prepared from the mean pressure data given in tables 1 and l a , showed that during Octnher a statistical low pressure area esisted in the lower levels over Fargo, N. Dak. In the higher levels this area es- tended east and west over the entire northern tier of States, but was centered over Sault Ste. hlarie, Rlich. Pressure, however, in the higher altitudes reached by radiosondes, continued lower over Fargo, N. Dak., as well as Sault Ste. Marie, Mich. Pressure was relatively low over the far Northwest, but it was high over the southern States a t all levels with the center apparently over Pensacoh, Fla. Mean pressures recorded over the country in October showed little difference from those noted during September, but they were slightly lower over the South in the upper levels, and decidedly lower over Fargo, N. Dak., a t all levels. High relative humidities prevailed during October over most of the Far West, the Pacific coast, and the Northeast, articularly over Spokane, Wash., and Sault Ste. Marie, &ich., a t all levels. This distribution coincided closely wit11 those sections of the United States that showed high percentages of normal precipitation for October, but differed from that condition which esisted in the previous month of September when high huniitlities were found over the eastern linlf of the country. The highest mean humidity for the United States was recorded over Sault Ste. Marie, htich., a t all levels. I t clirniiiished steadily from 90 percent a t the surhce to 56 percent a t 5 kilo- meters, and 47 percent a t 9 liilometers. El Paso, Tex., reported the lowest humidity recorded in the lower levels (39 percent), but this wizs increased to 60 percent, a t 4 kilometers. Over Norfolk, Va., the lowest humidity re- ported at all levels above 2 kilometers (32 lercent nt, 4 kilometers) was noted. This situation he I d generally over most of the rest of the South and Southeast. But a t Omaha, Nebr., while mean relative humidities were COR+ parntively high at a11 levels, that State reported the small- est amount of precipitation of any during October (11 percent of normal). Resultant winds in the free atmosphere, based on pilot- balloon observations made new 5 a. m. (75th meridian tinie), are shown in table 2. The resultant wind directions remained much closer to their normals during the month of October than in the preceding month of September when unusually wide divergences were noted. However, there were several outstanding departures in resultant velocities from normal observed in October, but these were mostly less than normal and confined generally to the 3- and 4- kilometer levels. The outstanding departures or differences between the October resultant directions and their normals in each level over the United States were: 163' a t hIedford, Oreg. (when the October direction is rotated in a clockwise direction away from its normal); 119', 87', 82', 96', and 86' (when rota ted counterclockwise) over Oakland, Calif. ; 162' (counterc,locIiwise) and 153' (clockwise) over Key West, Fla. ; and 75' (counterclockwise) over Spokane, Wash.; a t the surface, 0.5, 1, 1.5, 2, 2.5, 3, 4, and 5 kilo- meters, respectively. The greatest departures of the resultant directions from normal a t all levels were noted over Oaliland, Calif.; Key West, Fla.; Rfedford, Oreg.; Atlanta, Ga.; San Diego, Calif.; and Nashville, Tenn. Over Oakland, Calif., the October resultant directions were 155', 235', 27S0, 270°, 244', 246'. 251', 305', and 332', as compared to the estnblished normfils of 156O, 354', 5', 352', 340', 332', 294', 2 7 2 O , and 313', a t the surface, and 0.5, 1, 1.5, 2, 2.5, 3, 4, and 5 kilometers, respectively. As previously recorded for several months in 1938, the stations a t St. Louis, Mo. ; Chicago, Ill. ; and Oklahoma City, Okla., again showed the least departures from the October resultant directions and their normitls a t all levels. Farther north, a t hledford, Oreg., the greatest departures occurred a t the surface and a t 0.5 kilometer, where the differences were 163' and 113', when rotated in a clock- wise direction. Above these levels the differences were much less, and the monthly resultants departed in an opposite direction with a counterclocliwise rotation away from normal. In the South, over Atlanta, Ga.; Nashville, Tenn. ; and Pensacola, Fla., decided variations from normal were noted in the upper levels. Above 1.5 kilometers they depnrted widely froin normal in a clockwise direction so that the winds were northerly. Atlanta, Ga.; showed outstanding departures a t all levels. These difl'ercnces were: lo', 25O, 26O, 62', 45', 53', 67', 64', and 68', departing in a clockwise direction northward from normal, OCTOBBR la88 332 MONTHLY WJ3ATHER REVIEW a t the surface, and 0.5, 1, 1.5,3, 2.5,3,4, and 5 kilometers, respectively. The distribution of resultant wind direc6ions over the United States a t all levels during October showed that, above the surface, the winds were almost gerierally from a westerly direction. -4t 1.5 kilometers 45 percent of t81ie winds fell in the northwest qusdra.nt, 32 perce,nt in tlie southwest, 14 percent in the southeast,, and 9 percent in tlie east,. Of all the winds having west,erly components those from the northwest qua.drant precloiiiiiiatecl slightly a t all levels up to 4 kilometers. At 5 kilometers, however, 50 percent of the winds were southwesterly, 37 percent. northwesterly, and 13 percent northeasterly. A small percentage of the directions fell in t,he northeast quadrant at all of the levels from 0.5 t.o 5 kilometers. Over Snn Diego, Calif., Seatt,le, Wash., Albuclnerque, N. Mes., a.nd Cheyenne, Wyo., the current ~&d tlirect,ions departed from normal by turning in n counte,rclocl~~~~lse rotation et all levels, while over Atlanta, Ga. (as esplnined), Boston, Mass., and Brooklyn, N. P., tlie winds departed from normal by rotating in clockwise directions. The departures in direckion a t each level over a,ll pilot-halloon stations were nearly equally divided-56 percent hnriiig comit~erc.lock~~-iue rohtions away from their normals, and the average shat.ion departure from nornia.1 for each level showed there was a st,eadp increase in the departure riif- ferences with dtiturle. These average differences (a.!l stations) betwcen t,he ciirrent resultant direct,ions and the norm& for each level were: 2O0, 3S0, 34O, 25O, 29O, 3 2 O , 35O, 44O, and 4 7 O , a.t tlie surface, and a.t 0.5, 1, 1 .5 , 2 , 2.5, 3, 4, aid 5 kilometers, respeclively. The 2-kiloinefer level showed the RiOSt consistent depmture in direction, for 63 percent of all stations recorded departures thn.t rotated count8ercloctkwise from their nornials. Resultant wind velocities during October were less than normil a t Bostjon, hiass., by negative differences of 0.8, 2.3, 3.8, 3.2, 4.0, 3.7, 2.7, and 5.6 meters per s,econd, at the surface, a,nd a t 0.5, 1, 1.5, 2, 2.5, 3,4, and 5 kilometers, reupective,ly. Tius sta.t,ion showed more negative depar- tures a.t ail consecutive levels t1ia.n tiny other st.ation In t,lie c,ountry. Billings, Mont., Cliica,go, Ill., Detroit, Micll., Spokane, M-n.sh., and St. Louis, Mo., reported snxdlcr negut.ive departures a t a11 levels. No station showed posit,ive (or grmter thnn normul) velocity de- prtures a t d l levels, but a t Pensxoln, Fla., Srtlt Lake City, Utah, and Snn Diego, Calif., large positive departure differemes were recorded n t most of the levels. In this respect, I'eiis~ola, Fla., indicn.t,ed the greatest positive diflerences for the country of 1.1, 3.0, 3.4, 2.7, 0.8, and 1.4 meters per second, a t 0.5, 1, 1.5, 3, 3.5, and 4 kilometers, respectirely. Light velocit,ies, 1x8 well as slight departures froin the resulta,nit veloc.it'y normals, occurred a t Oakland, Calif., Fitrgo, N . Dnk., Nashville, Te.nn., Key West, Fla., and At,lantn, Ga.. Several of these stations showed, as a re- sult, ou tstanding resultzmt direction departures from normal. htasirnuni wind vdocities for October, as shown in tn.ble 3, occurred a t a nuniber of stations ove,r the Umted St.nt.es. Winds having a speed of 50 meters per second or inore (1 14 miles per hour or more) were reported from. Las Vegas, Nev., Gre,ensboro, N. C., Evansville, Ind., Rillmgs, hiont., Denver, Colo., and Albuquerque, N. hilex., a t cliflerent levels. Tlie highest velocity reported was 78.0 ni. p. s. (174 miles per hour) froin the SW., over Denver, Colo., in the 17t81i, n t 8 kilometers. The greatset velocit recorded nen.rest the surface was 34.8 rn. p. s. over M e J ford, Oreg., a t 0.8 kilometer, and that at the greate5t altitude re:tc,hed was 50.2 in. p. s. over Albuquerque, h. Mex., a t 14 kilometers. TABLE I.-Aean free-air barometric pressures (P ) in nib., temperatures (T ) in 'C., and relative humidities (R . H.) in percent obtained by air planes during October 1938 1 Navy. Ohsprrations taken aboitb -1 n. rn. 75th mcridion time, except by Nary stations s l o ~g lhe Facllic coact end Bawrtii ahe;e the). are taken at dawn. NOTs.-None of the ~R S I I S Included in t h k talrle are based on less than 15 surface or S-standarrl-lrvr I obcervations. OCTOBER 1938 MONTHLY WEATHER REVIEW 333 TABLE la.-hlean free-air barometric pressures (P ) in mb., temperatures (2') i n "C., and relative humidities (R . H.) in percent obtained by radiosonde during October 19% I Stationa and elevations in meters above sea level A Navy. Observations taken abnut 1 R. m. i5th meridian time, ewept by Navrstatinns alon: tli? Pacifir coast and Hawaii where they are taken at dawn. NOTE.-None 01 t.he m93n'i included in t!iis tahlc arc h s s d on IPSS than 15 siirfare or 5-standard-lrsrl oLIS~rV:itinnR. Number of ohsrrvations refers to preswre only as temperature and hunlidity data are missing for some observations at certain levels also the humidity data is not used in daily observations when the temperature is belov.' -10' C. TABLE 2.-Free-air resultant winds (meters per second) based on pilot-balloon observations made near 5 a. m. (E. S. T.) during October 1958 [Wind from N=3Pn0, E=90°, etc.] Altitude (meters) m. 8. 1. -I 1 7 -11- _- i? .B f a .t: c 2 s 0 E -- 2. 2 27.1 4 .8 ._._.. 5.0 ....-. 5.0 ...-.. 4.9 ?liY 5.5 269 369 ,. 3 1 ?6fi ___.. 916 2. s _____- - R .B h S .- a .t: 'Z 0 2 0 o o o u _-_- 0 1.4 2i5 2.1 336 2.4 ____._ .____ 353 3.5 __.__. ._... 318 2.2 2% 3.1 307 263 4.4 312 s o -5. 2 ?ne 3.9 277 5.7 30i 4.1 24s 2.2 351 2.4 .__... .____ ----- ;:; .- 2 5 2 - x E Z 5 5 ; --- 2.5 335 0.4 5 .2 315 0.7 3.6 154 1.5 1.3 175 2. 1 0.4 201 4. a 0.6 231 3.0 0.9 251 2.5 0.7 i ~i i 4.0 . -. . - -. -. . - - - - - I .- -x g g s c, 0 c) u 2 E 0 .- E g E P n ---- 1.3 53 0.4 237 4.3 213 1.3 251 5.1 .in 3.3 ?!I5 F. 3 29tj 4.0 273 6. 1 3119 4. 4 2913 0. 1 314 3. fi 290 6.6 339 4 .1 2% ___.. 32s 6.4 306 __._...-_._ --.-- -- 1.4 50 1.4 59 2. 1 I?? 2. 5 15:? 3.3 190 3 3 300 3.9 ._._. 2.: 91 3.n 11s 0 1.5 345 2. 6 Y 1,s 35n 4.0 313 4.3 31.5 5 .i 32'3 ,. , 324 5.5 34i __ - - - - . - . - . 1 1 IT--- - Altltude (meters) m. s. 1. -I I- I I- -41- -~ R 8 2 5 E 0 B a s 0.6 3zn 1.1 .2 J - 0 " _-- 0 __._ 346 3.6 1.3 350 4 0 1.9 333 5.3 1.9 334 5.5 3.0 318 5.5 3.2 310 6.2 3.5 341 7.5 3.2 ______ _____ -- .- 2 ; P i 5 0 " 0 0 - -- 3.5 25 __.. 3X1 -... 314 5.5 27s 5.2 202 4.4 19s 4.2 207 5.? IS9 3.8 214 ~- B 2 .E S i B E 5 .- a "0 " 2 0 E --- 224 0.4 153 I6C 2.1 235 278 1.6 276 312 2.8 270 334 4.0 244 336 4.0 246 337 3 .4 251 353 4.3 306 18 4.0 332 .- 2 ; "0 2 2 f a -- 1.3 154 3.0 ..... 5.2 ''26 4.5 232 5.3 92Y __._ 221 __._ 199 5.0 18s .___ 250 .- u o o o 0 2 0 E B E B E ___-- 0 1.1 47 2.6 34 4.3 71 5.4 55 s. 3 80 5.7 55 8.4 83 4.4 43 7. Y 85 4. 1 310 6. s 76 2. 4 6.5 26 2.3 316 ..__. 9 3.6 ----- 7.0 73 2.0 4: g o "" - E O E S i 5 B E _--- 0 1.0 16i 2.9 166 1.3 , 179 5.2 205 1. 3 199 S.0 2 4 ) 2.7 218 4.7 245 I.!? 243 3.4 2Gl 1.8 S O 2.7 ?S? 2.6 319 3.6 299 4.0 ._.___ ____. ____. 2. I 2 ~4 3.n 272 _-_- 0 0.8 YS 1.0 145 1.7 1% 1.4 l i 5 1.8 , 271 4.2 194 1.0 ?ii 8.3 ?!IS 2.2 243 8.9 202 3.0 302 7.3 185 2.Y 303 8.0 ____.. 4.6 __.___ ___.. 7.6 ____._ _____ I Navy statlons. 334 MONTHLY WEATHER REVIEW OCTOBER 1938 Northeast 1 ______ Esst-Crutral i--- Soiithemt 3 ...___ North-Cencra14.- Centrals ...._.... South-Central 6.- TABLE 3.-filazin~um free air wind velocities (m. p . s.), for different sections of the United States, based on pilot balloon observations during October 1938 39.2 SW __.._ 2,140 30.2 WSW--. 2.230 2s. 2 WN1V.- 2.500 3 .1 N N E ... 1,000 35.4 IV _______ ?.3!0 29.2 S .._____. 1.630 Above 5 ,W meters (m. 5.1.) ~~ ~~~ ~ ~ Sortace to 2,500 meters (m. s. 1.) 11 Betwem 2.500 and 5,000 meters (m. s. 1.) I 26 26 27 14 5 17 Cleveland, Ohio.-.-. 3~ 0 Cincinnati, Ob10 _____ 31. 0 Spartanhurq. S . C ____ 34. C Huron. S. Dak _.____. 41.8 Eranwille. I d _.._.. 36 X Amarillo, Teu .._____ 26 6 S W W .____ . STY.. . NNW ... NN\$"... NW--. ~ 3.;00 18 Cleieland. Ohio ______ 30.0 WNW-- 9.SO 15 3.J.90 26 Cintinncdi. Ohio ..... 50.0 SW .--.. 6.840 24 C..oDll 2-1 Char1e:tou. 8 . C __.__ 46.0 YW _..._ G.960 24 4.930 26 Farpo, iX Dsli .____ __ 4Y.0 W ....--. 9.130 13 3.230 27 Arolino. 111 54.0 WNW.- 11.~130 25 3.910 23 Oklahouin C i t s. 45.0 IY 12.330 21 26 14 15 station Aledford. Oreg _______ 35.0 Salt Lake City. Utali. 34.4 Las Vepas. Nev ______ 50.0 ll Cleveland. Ohio. Greensbolo, N . C. Chnrleqton, 6. C. Fargo. N. Uak. ET:ansrille, Inil. Oklahoma C 1 t p. B i l l i n s , Mont. Denver Colo. Albuqu&que,N. Mer. Okla. I Maine, Vermont. New Hampshire. Massachusetts, Rhode Island, Connecticut. 2 Delaware, Maryland. Virginia, West Vlrginin, southern Ohio, Kentucky, eastern I South ksrolina Georgia. Florida, and Alsbama. 4 hIichipan Wislonsin, Minnesota, N0rt.h Dakota, and South Dakota. 5 Indiana, illinois. Iowa, Nebraska, Kansas. and R.1 issouri. 0 A1 tssissippi, .4rkausns, Louisiuna, Oklahoma, Texas (except El Psso), and western ' 31 Ontnna. Idoho. Washi:igton. and OrrgOU. 8 Wyoniin- Cnlmido Utah northern Nevada, and nort.hern Cdifornla. 9 Snuther~'Calih,rnis,' soutiern Nevada, Arizona, New Mexico, and estreme west New Tork, New Jersey. Pennsylvanis. nnd northern Ohlo. Teymssee ann N0rt.h Carolina. Tennessee. Texas. RIVERS AND FLOODS [River and Flood Dirlsior:. MURRILL B~RNIRD in charge] By BENNETT SWENSON No floods occurred during the month of October 1938 with the exception of floods in the upper Mississippi Basin and in the lower Rio Grande which were a continu- ation of oveiflows that begn.n in September. The flood in the upper Mississippi will be discussed below. Tllo overflow in t,lie Rio Grande WAS limited to the extreme lower reach of the river. Flood stage was esceeded at8 Mercedes and Brownsville, Tes., from September 29 to October 3 and crested on October 1 a t a stage of 22.0 feet a t the former station and 18.6 feet a t t'he latter. The principal damage in this flood was caused by a bren.k in the main levee, on the American side of t,he river, about 2 or 3 miles above Brownsville, Tes., resulting in inundat,ion of approximately 1,200 ncres of land. The total damage hn.s bee,n estimated a t $2,500. The upper hlississippi flood resulted from heavy rains over southern Minnesota, sou thern Wisconsin, northern Illinois, and centrnl and nort,liern Iowa. The flood was largely a tribut,ary flood, with the Chippewa, Black, Wisconsin, Zumbro, and llliitewater Rivers particulurly , experiencing unusually severe floods. The heavy rains began about September 5 and cont,inued until September 14, and occurred again from the 17th to the 19th, but the rains of the latter pei-iod were not generally as intense and did not have a great effect on t'he high water escept to prolong it somewhat. Figure 1 shows the distribution of precipitation from September 5 to 14. The dn.ta used in the preparation of the isohyets may be found in CZiinat obog