[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI FEB 21 2014

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
A STRONG PRESSURE GRADIENT BETWEEN A BROAD SURFACE RIDGE OVER
THE NORTH ATLC EXTENDING INTO THE CARIBBEAN AND LOWER PRESSURE
ACROSS THE NORTHWESTERN SOUTH AMERICAN CONTINENT IS GENERATING
GALE FORCE NE WINDS IN CLOSE PROXIMITY TO THE COAST OF COLOMBIA
FROM 11N TO 13N BETWEEN 74W AND 76W WITH SEAS FROM 10 TO 15 FT.
THESE WEATHER CONDITIONS ARE FORECAST THROUGH FRI NIGHT. SEE
LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC
NEAR 10N14W AND CONTINUES TO 6N16W TO 3N20W. THE ITCZ BEGINS
NEAR 3N20W AND CONTINUES TO 1N26W TO 1S32W. SCATTERED MODERATE
CONVECTION IS FROM 2S-3N BETWEEN 20W-38W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH WITH AXIS ACROSS CENTRAL U.S. AND
BASE OVER THE NW GULF SUPPORTS A FRONTAL SYSTEM THAT ENTERS AS A
COLD FRONT FROM SW LOUISIANA NEAR 29N93W TO CORPUS CHRISTI
TEXAS. THE TROUGH ALOFT ALSO SUPPORTS A PRE-FRONTAL TROUGH FROM
29N92W TO BROWNSVILLE TEXAS. SSMI TPW IMAGERY SHOW MOISTURE
ADVECTION FROM THE CARIBBEAN REACHING THE N-NW GULF COAST. A
DEEP LAYER RIDGE WITH AXIS ALONG THE EASTERN U.S. COASTLINE IS
GENERATING DIFFLUENCE ALOFT WHICH ALONG LOW-LEVEL MOISTURE
CONVERGENCE SUPPORT A SWATH OF HEAVY SHOWERS AND TSTMS FROM THE
LOWER GREAT LAKES SW TO THE LOWER MISSISSIPPI VALLEY AND INTO
THE GULF N OF 27N BETWEEN 90W-95W. WATER VAPOR IMAGERY SHOW
MOSTLY DRY AIR IN THE MIDDLE LEVELS ACROSS THE REMAINDER GULF
WITH SOME UPPER LEVEL MOISTURE BEING ADVECTED FROM THE E PACIFIC
INTO THE WESTERN GULF BY WESTERLY FLOW. SURFACE RIDGING CONTINUE
TO EXTEND FROM THE ATLC INTO THE EASTERN GULF THUS PROVIDING
RETURN FLOW OF 15 KT ACROSS THE ENTIRE BASIN WITH HIGHER WINDS
UP TO 20 KT IN CLOSE PROXIMITY OF THE FRONT. THE FRONT WILL
CONTINUE TO MOVE SE TO EXTEND FROM TALLAHASSEE FLORIDA SW TO THE
BAY OF CAMPECHE BY FRIDAY MORNING. THE FRONT IS EXPECTED TO
STALL ACROSS NORTHERN FLORIDA AND THE EASTERN GULF FRI NIGHT AND
WILL START DISSIPATING BY SAT MORNING.

CARIBBEAN SEA...
NW TO W WIND FLOW ALOFT FROM THE NW TO EASTERN CARIBBEAN THIS
MORNING WITH WATER VAPOR IMAGERY INDICATING DRY AIR SUBSIDENCE
ACROSS THE ENTIRE BASIN. THIS DRY AIR SUPPORTS MOSTLY FAIR
WEATHER BASIN WIDE. HOWEVER...PASSING SHOWERS ARE EXPECTED
TONIGHT FOR PUERTO RICO AND THE VIRGIN ISLANDS ASSOCIATED WITH A
WESTWARD MOVING MOIST AIRMASS JUST NE OF THE LEEWARD ISLANDS. IN
TERMS OF WIND...EASTERLY TRADES OF 20 KT DOMINATE ACROSS THE
BASIN EXCEPT FOR THE CENTRAL CARIBBEAN WHERE WINDS ARE UP TO 25
KT WITH GALE FORCE WINDS ALONG THE COAST OF COLOMBIA. GALE FORCE
WINDS FOR THE ABOVE MENTIONED REGION ARE EXPECTED TO CONTINUE
THROUGH FRI NIGHT. SEE SPECIAL FEATURES SECTION FOR MORE
DETAILS.

...HISPANIOLA...
CURRENTLY FAIR WEATHER CONDITIONS ON THE ISLAND BEING SUPPORTED
BY DRY AIR AT THE LOWER LEVELS AND ALOFT. MODEL GUIDANCE
INDICATE SIMILAR CONDITIONS TO PREVAIL THROUGH EARLY FRIDAY. A
MOIST AIRMASS IS EXPECTED TO ENTER THE ISLAND LATE FRIDAY
MORNING WHICH MAY ENHANCE SHALLOW CONVECTION. SKIES MAY CLEAR
OUT AGAIN SAT MORNING WITH THE ADVENT OF A LOWER LEVEL DRY
AIRMASS.

ATLANTIC OCEAN...
A WEAK SURFACE PRE-FRONTAL TROUGH EXTENDS FROM 31N58W TO 27N61W.
DIFFLUENCE ALOFT IS ENHANCING ISOLATED SHOWERS EAST OF THE
TROUGH N OF 21N BETWEEN 51W-62W. OTHERWISE...A BROAD SURFACE
RIDGE DOMINATES THE ENTIRE ATLC WATERS ANCHORED BY TWO HIGH
PRESSURE CENTERS...A 1028 MB HIGH NEAR 32N65W AND A 1036 MB HIGH
NEAR 37N29W. A WEAK COLD FRONT IS FORECAST TO ENTER THE SW N
ATLC SAT MORNING WHICH THEN WILL TRANSITION TO A STATIONARY
FRONT THROUGH SUN MORNING.

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

$$
NR


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