[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST WED JAN 26 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ANALYZED ALONG 5N10W 5N22W 3N30W 3N40W CROSSING
THE EQUATOR AT 50W. CLUSTERS OF MODERATE TO STRONG CONVECTION
ARE NOTED S OF THE ITCZ AXIS TO 1N BETWEEN 6W AND 15W. SCATTERED
MODERATE CONVECTION IS WITHIN 90-100 NM N OF AXIS FROM 22W TO
33W. SIMILAR CONVECTION IS S OF AXIS TO THE COAST OF SOUTH
AMERICA BETWEEN 44W AND 47W.

...DISCUSSION...

GULF OF MEXICO...
AT 26/1500 UTC...A COLD FRONT EXTENDS FROM FORT MYERS SW FLORIDA
ACROSS THE SE PORTION OF THE GULF CROSSING THE YUCATAN PENINSULA
TO NEAR 18N93W. MOST OF THE STRONG SHOWER AND TSTMS ACTIVITY
NOTED AHEAD OF THE FRONT SINCE YESTERDAY HAS DIMINISHED AND THE
THREAT OF SEVERE TSTMS HAS ENDED OVER THE STATE OF FLORIDA.
HOWEVER...ADDITIONAL SHOWERS AND A COUPLE OF TSTMS ARE STILL
POSSIBLE WITH THE FRONTAL PASSAGE ACROSS SOUTH FLORIDA THIS
AFTERNOON. A PRE-FRONTAL THROUGH IS OVER THE YUCATAN CHANNEL AND
EXTENDS FROM 24N84W TO 18N86W. THE 1212 UTC WINDSAT PASS
PROVIDED OBSERVATIONS OF NW TO N WINDS OF 20 TO 30 BEHIND THE
COLD FRONT E OF 90W. COLD AIR STRATOCUMULUS CLOUDS ARE SEEN
COVERING MOST THE GULF WATERS BEHIND THE FRONT DUE TO THE
ADVECTION OF COLD AIR OVER RELATIVELY WARM WATERS. PERSISTENT
LOW CLOUDINESS ARE ALSO BANKED UP ALONG THE E SLOPES OF THE
SIERRA MADRE MOUNTAINS. THE FRONT WILL QUICKLY MOVE SE OF THE
GULF BY LATE THIS AFTERNOON. HIGH PRES WILL BUILD IN ITS WAKE
FROM W TO E ACROSS THE REGION THROUGH SUN. AS A RESULT...WINDS
AND SEAS WILL GRADUALLY DIMINISH ACROSS THE REGION. ALOFT...A
STRONG SHORT WAVE TROUGH MOVING E OVER THE SE CONUS SUPPORTS THE
AFOREMENTIONED COLD FRONT WITH SW TO W UPPER LEVEL FLOW
DOMINATING THE GULF REGION.

CARIBBEAN SEA...
BROAD UPPER RIDGE DOMINATES THE CARIBBEAN SEA ANCHORED OVER
EASTERN COLOMBIA. STRONG UPPER LEVEL SUBSIDENCE WITH THE IMPLIED
DRY AIR MASS COVERS MOST THE BASIN WITH THE EXCEPTION OF SOME
MID/UPPER LEVEL MOISTURE OVER THE FAR NW CARIBBEAN ASSOCIATED
WITH A PRE-FRONTAL TROUGH. FRESH TO STRONG TRADE WINDS CONTINUE
TO BLOW ACROSS THE EASTERN AND CENTRAL CARIBBEAN WITH THE
STRONGEST WINDS UP TO 30 KT NEAR THE COAST OF COLOMBIA DUE TO
THE PRESSURE GRADIENT BETWEEN THE RIDGE N OF AREA AND THE
COLOMBIAN/PANAMANIAN LOW THAT USUALLY RESIDES IN THIS REGION.
THE 1032 UTC WINDSAT PASS AND THE 1408 UTC ASCAT PASS ALONG WITH
SOME SHIP OBSERVATIONS VERIFIED THESE WIND SPEEDS. THESE WINDS
ARE EXPECTED TO DIMINISH THROUGH THU NIGHT BUT RETURN SUN AS
HIGH PRES BUILDS SE INTO NORTHERN CARIBBEAN BEHIND A COLD FRONT
FORECAST TO BECOME STATIONARY FROM CENTRAL CUBA TO THE GULF OF
HONDURAS TONIGHT THROUGH THU AND DISSIPATE EARLY FRI. PATCHES OF
LOW LEVEL MOISTURE REMAIN EMBEDDED WITHIN THE TRADE WIND FLOW AS
SEEN ON VISIBLE SATELLITE IMAGERY USHERING IN ISOLATED TO
SCATTERED PASSING SHOWERS.

ATLANTIC OCEAN...
A COLD FRONT IS JUST ENTERING THE NW PORTION OF THE SW N ATLC
AND EXTENDS FROM 31N78W TO SW FLORIDA INTO THE GULF OF MEXICO.
A NARROW BAND OF SHOWERS AND TSTMS IS AHEAD OF THE FRONT AND IS
CURRENTLY AFFECTING THE NW BAHAMAS. GALE FORCE WINDS ARE
EXPECTED AHEAD OF THE FRONT THROUGH EARLY TONIGHT...AND A GALE
WARNING REMAINS IN EFFECT N OF 29N W OF 75W. ANOTHER COLD FRONT
ENTERS THE FORECAST AREA NEAR 31N38W THEN CONTINUES SW AND THEN
W TO NEAR 23N53W WHERE IT BEGINS TO DISSIPATE AS A STATIONARY
FRONT ALONG 22N65W TO THE TURKS AND CAICOS NEAR 21N72W. SOME
SHOWERS ARE ALONG THE FRONTAL BOUNDARY. A BELT OF 20-25 KT NE
WINDS IS NOTED PER AN EARLIER WINDSAT PASS WITHIN AROUND 180 NM
N OF THE DISSIPATING FRONT BETWEEN 57W AND 67W. NLY WINDS IN THE
20 TO 25 KT RANGE ARE ALSO OBSERVED BEHIND THE COLD FRONT E OF
47W. A THIRD COLD FRONT IS MOVING ACROSS THE CANARY ISLANDS
FOLLOWED BY FRESH TO STRONG WINDS. IN THE UPPER LEVELS...A HIGH
AMPLIFIED RIDGE/TROUGH PATTERN DOMINATES THE AREA. THE BROAD
UPPER RIDGE THAT COVERS THE CARIBBEAN SEA EXTENDS NWD OVER THE W
ATLC TO BEYOND 31N70W. AN UPPER TROUGH IS OVER THE E-CENTRAL
ATLC AND RUNS FROM 31N18W TO 17N37W TO 10N50W. A JET STREAM
BRANCH WITH CORE WINDS OF 70-90 KT ROUNDS THE BASE OF THE TROUGH
AND EXTENDS NE THEN E INTO NORTHERN AFRICA. THE REMAINDER OF THE
E AND CENTRAL ATLC IS UNDER THE INFLUENCE OF HIGH PRES WITH
MOSTLY FAIR CONDITIONS.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
GR





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