JANTJAEY 1940 MONTHLY WEATHER REVIEW 29
Depar-
;:z normal
Millibar8 +9.4 -3.0 -2.2 +2.2
+LO -1.1 -2.7
+.3 -4.7 -9.2 -1.7
+.Z -1.6 +.9 -1.8 -6.3
NORTH PACIFIC OCEAN, JANUARY 1940
By WILLIS E. HURD
Atmospheric pressure.-Most unusual and persistent conditions of low atniospheric pressure overspread the middle waters of the North Pacific during January 1940. While the center of the Aleutian LOW occupied a normal position over or a little south of the Aleutian Islands, cyclonic conditions spread far to the southward, with the result that, even in the latitudes of Midway Island and Honolulu the customary winter antic clone was, on the average, completely nonexistent. At fIonolulu the aver-
age ressure of 1,011.2 millibars (29.86 inches) was 4.7
mild 1 ars (0.14 inch) below the normal of the month; while at Midway Island the average pressure of 1,007.7 millibars (29.76 inches) was 9.2 millibars (0.27 inch) below the normal, or the lowest of record there for any month during the past 29 years. Minus pressure depar- tures, though in decreasing value, continued as far to the eastward as the west coast of the United States, and as
far to the soutliwestword as about the 135th meridian of east longitude. The lowest barometer reported by any Pacific vessel this month was 967.1 millibars (28.56 inches) read on the Japanese motorship Amagisan Maru on the 25th) near 40' N., 135' W. It was accompanied
by a south-southeast gale of force 9. The North Pacific anticyclone occupied a small region to the southwestward of California. In Asiatic waters the continental antic clone extended oceanward from the
TABLE l.-Auerages, departures, and extremes of atmospheric pressure at ma level, North Pacific Ocean, January 1940, ad selected stations
China coast to a litt r e beyond the Nansei Islands.
Highest
-_I_
MfUiborc 1047
1,026 1 om
1:026 1 018 io17 1,016 1,016 1,018
1'021 1:021
1'029
?E 1,021 1,013
atations Date
14 11 1 11 18 14 16 11,s
30 4 11 28
23 26 11 31
Average
P- Lowest Date
---
MUlfbara 988 10 970 22 8 8 4 2 3
fS2 16 37 a8 994 1 7 13-16,lS 1.006 19 990 31 1,004 aa 1,009 16 1,010 16 1,012 12,16 1,006 13 976 12
MiUihars 1, m. 0 W7.8 1.001. 2 1.004. 2 1.012.9 1,014.2 1 016.9 1: 014.6 1,011.2 1,007.7 1,010.8 1,012.4 1 018 1 1: 010: 6 1,014.6 888.8
Nmr.-Data based on 1 dally observation only, except those for Juneau, Tatoosh Idand 8an Francism, and Honolulu, which am baaad on 2 obmrvatlona. Departures m corhputed from best available normals related to time of observation.
Extratropical y&nes and gales.-The storminess of January 1940, was abnormal on the North Pacific Ocean. Except to the eastward of the 140th meridian of west longitude, stormy weather to the northward of the 40th parallel was perhaps the least pronounced of record for a
winter month in that great regon. In fact, for the entire area north of 35' N., and west of 150' W., only 4 or 5
d a p with gale winds (force 8 to 10) are to be notedin
sbi 8' reports. 8n the c o n t r a , over the eastern part of the ocean, from
northern Uni States coastal waters, and extending southwestward broadly along the routes toward the Hawaiian Islands, extrmrdinaril storm conditions for
an wintar month prevailed. H t z ere ra er densely dis- tziguted gales of force 8 to 10 occurred on no less than 20
days, whch ap ears to constitute a record for gale fre- quency, partic up arly to the southward of the 35th parallel
in these waters.
Another stormy region was the belt of 30' to 35' N., between the meridians of approximately 145' E. and 160'
W. Along this strip the heaviest wmds of the month occurred, attaining force 11 on the 9th, loth, 13th, 17th) and 19th. In these latitudes while en route from the Philippine Islands toward San Pedro, the Norwegian motorship Bonnedle had probably the most tempestuous voyage of any ship of the month on the North Pacific Ocean. On January 8 she entered the stormy weather belt near 32'
N., 145' E. On the 21st she finally emerged from it, near 32' N., 160' W. During the period the vessel en- countered daily gales, as strong as force 10 on the llth, 12th, 16th) and 20th, and as high as force 11 on the 9th, loth, 17th, and 19th. The lowest barometer read on the BonnewiUe during the voyage was 985.4 millibars (29.10 inches) occurring on the 18th, in 32'30' N., 168'14' W. Along the immediate coast of the United States, prin- cipally off Washington and Oregon, ships reported gales on the 1st) 3d, 4th) 7th) 24th) 25th, and 2Gt11, all of force 9 except that of the 7th, southeast, force 8, and that of the 3d, southenst, force 10, both off the coast of southern Oregon. These gales occurred in connection with cyclones centered at some distance to the westward. Tehuantepecer8.-There was considerable wind activity in the Gulf of Tehuantepec during January, with Tehu- antepecers reported on 9 days, as follows: Of force 8 on the 8th, 20th) and 25th; of force 9 on the 16th, 23d, and 24th; and of force 10 on the 15th) 27th) and 28th. Fog.-Fog was reported altogether along the northern routes between 180' and 133' W. on 8 days, during the Along the California-
5 awaiian routes, exclusive of coastal waters, there were 9 days with fog, scattered through the month. In California coastal waters ships reported fog on 9 days, and in northern Lower California waters, on 1 day.
ADDITIONAL NOTE ON THE MEXICAN WEST COAST
eriod from the 18th to the 29th.
CYCLONE OF OCTOBER 23-25, 1939
By WILLIS E. HURD
In the MONTHLY WEATHER REVIEW, October 1939, under the heading "North Pacific Ocean," mention was made that a tropical cyclone occurred off the Mexican west coast on October 23-25, 1939, and that the American steamer Nevadan was reported severely battered by the storm off Manzanillo.
In the issue of the United States Department of Com- merce Bureau of Marine Inspection and Navigation Bulletin for December 1939, is quoted the report of Capt. J. H. Masse, of the Nevadan, on the ship's experiences in the cyclone while northbound for Los Angeles.
At 6:35 p. m. of October 24 the vessel had Manzsnillo Bay light abeam. At 8 p. m. warning was received from San Francisco of a tropical disturbance centered near
and southwest of Manzanillo. At 11 p. m., in a fresh gale and noticeably falling barometer, the ship turned left for sea room. Quoting from the captain's report,, beginning with 1 a. m. of the 25th:
Between four and five a. m. it dropped 1.3 inches to 28.00 and at 6: 30 a. m. reached as low as 27.40. The center was passing over the ship. Wind and rain let up, but mountsious Bern continued to roll in from all sides * * *. Immediately the storm center had pessed, win& came in once again of hurricane force, with the attending mountainous sem. Visibility waa nil; in fact, breathing without a towel over one's nose was difficult, the air was so saturated with sea water. With the great difference of pressure within the ship as against the pressure without and the added impetus of humcane winde, tar-
From one o'clock on the barometer dropped fast.