[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 180001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE FEB 17 2015

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

...SPECIAL FEATURES...

...GALE WARNING FOR THE W ATLC...

A GALE WARNING IS N OF 30N W OF 73W UNTIL 0000 UTC WED. PLEASE
SEE THE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS
MIAHSFAT2/ FZNT02 KNHC FOR MORE DETAILS.

...GALE WARNING FOR THE GULF OF MEXICO...

A GALE WARNING WILL COMMENCE AT 1200 UTC WED S OF 21N W OF 95W
ASSOCIATED THE TIGHT PRESSURE GRADIENT BEHIND THE COLD FRONT
PRESENTLY ACROSS THE GULF. THE GALE WINDS ARE FORECAST TO
DIMINISH TO BELOW GALE FORCE AT 1800 UTC WED. PLEASE SEE THE
LATEST 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 08N13W TO 04N20W WHERE THE ITCZ BEGINS AND CONTINUES TO S
OF THE EQUATOR AT 26W AND TO THE COAST OF S AMERICA AT 3S40W. NO
SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

GULF OF MEXICO...
IN THE UPPER LEVELS...A STRONG UPPER TROUGH IS SWINGING EASTWARD
ACROSS EASTERN TEXAS AND THE FAR NW GULF FOLLOWED BY A DRIER
AIR. WEAKENING HIGH PRES IS ELSEWHERE TO THE SE OF THIS TROUGH.

A THE SURFACE...STRONG HIGH PRES ANCHORED BY A 1026 MB HIGH
CENTER OVER WESTERN TEXAS...AND A 1025 MB HIGH OVER SW ARKANSAS
IS BUILDING SEWD ACROSS THE GULF BEHIND A COLD FRONT THAT
EXTENDS FROM JUST OF TAMPA SW TO 26N90W TO THE SW GULF OF
MEXICO...AND INLAND MEXICO AT 18.5N95W. AMPLE DEEP MOISTURE IS
BEING ADVECTED NEWD ALONG...AND TO WITHIN 180 NM EITHER SIDE OF
THE FRONT PRIMARILY DUE TO A JET STREAM BRANCH THAT EMERGES FROM
ACROSS THE EASTERN PACIFIC NEWD ACROSS THE GULF. LATEST NWS
RADAR IMAGERY SHOWS A LINE OF SCATTERED SHOWERS WITH ISOLATED
TSTMS WITHIN ABOUT 60 NM SE OF THE FRONT E OF 84W. THE LATEST
SATELLITE IMAGERY SUGGESTS THAT ISOLATED SHOWERS ARE POSSIBLE
ELSEWHERE ALONG AND WITHIN 90 NM OF THE FRONT. THE BUOY
OBSERVATIONS REVEAL NORTHERLY 15-20 KT WINDS N OF THE
FRONT...WHILE S-SW WINDS OF 10-15 KT ARE S OF THE FRONTAL
BOUNDARY.

THE UPPER TROUGH WILL SHIFT EASTWARD THROUGH TO E OF FLORIDA BY
EARLY THU ALLOWING FOR THE COLD FRONT TO REACH THE STRAITS OF
FLORIDA TO THE NW CARIBBEAN NEAR 20N87W EARLY ON WED...AND
FURTHER ACROSS THE NW CARIBBEAN THU. MOISTURE GUIDANCE SUGGESTS
THAT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN
POSSIBLE WITH THE FRONT AS IT MOVES INTO THE NW CARIBBEAN. HIGH
PRESSURE WILL DOMINATE THE AREA THROUGH THU.

CARIBBEAN SEA...
IN THE UPPER LEVELS...BROAD ANTICYCLONIC FLOW COVERS THE BASIN
WITH THE CULPRIT ANTICYCLONE SITUATED ALONG THE W COAST OF COSTA
RICA. WATER VAPOR IMAGERY SHOWS ABUNDANT MODERATE TO STRONG
SUBSIDENCE COVERING THE ENTIRE SEA FOR THE TIME BEING.

AT THE SURFACE...THE TAIL END OF A DISSIPATING SURFACE TROUGH SW
FROM THE CENTRAL ATLANTIC TO THE NE COAST OF HISPANIOLA.
ISOLATED SHOWERS ARE POSSIBLE WITHIN 60 NM OF THE TROUGH. THE
BUOY OBSERVATIONS ALONG WITH A FEW RECENT SHIP REPORTS REVEAL
GENERALLY E WINDS OF 15-20 KT...WITH THE EXCEPTIONS OF THE NW
CARIBBEAN WHERE WINDS ARE SE 10-15 KT...AND THE S CENTRAL AND SW
PORTIONS WHERE A TIGHTER PRESSURE GRADIENT THERE IS ALLOWING FOR
NE-E WINDS OF 20-25 KT.

THE ABOVE MENTIONED UPPER ANTICYCLONE IS FORECAST TO SHIFT
WESTWARD OVER THE NEXT 24-48 HRS IN RESPONSE TO BROAD UPPER
TROUGHING THAT TRANSLATES EASTWARD OVER THE GULF OF MEXICO. THIS
WILL PUSH A COLD FRONT TO THE NW CARIBBEAN BEGINNING LATE
TONIGHT...AND REACH FROM EASTERN CUBA TO THE GULF OF HONDURAS
WED NIGHT BEFORE BECOMING STATIONARY AND WEAKENING FROM
HISPANIOLA TO NICARAGUA THU NIGHT. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WILL BE EXPECTED WITH THE FRONT AS IT
MAKES HEADWAY ACROSS THE NW AND N CENTRAL CARIBBEAN PORTION
THROUGH THE NEXT 24-48 HRS.

...HISPANIOLA...
WATER VAPOR IMAGERY SHOWS STRONG SUBSIDENCE ALOFT CONTINUING TO
HINDER THE DEVELOPMENT OF DEEP CONVECTION. THE LAST IMAGES OF
THE VISIBLE SATELLITE SHOWS BROKEN LOW CLOUDS WITH SCATTERED
SHOWERS IN SOME SPOTS MAINLY OVER THE MOUNTAINOUS REGION OF THE
DOMINICAN REPUBLIC. SCATTERED TO BROKEN LOW CLOUDS ARE OVER THE
INTERIOR OF HAITI...BUT DECREASING WITH LOSS OF HEATING. THE
SUBSIDENCE ALOFT SHOULD GRADUALLY GIVE WAY TO A MORE MOIST AND
UNSTABLE PATTERN AS MOISTURE ADVECTS EASTWARD FROM GULF OF
MEXICO AND COMBINES WITH LOW LEVEL MOISTURE MOVING WESTWARD FROM
THE EASTERN CARIBBEAN THROUGH THE NEXT 48 HRS. THIS SHOULD BE
SUFFICIENT TO BRING AN INCREASE OF SCATTERED SHOWERS TO SOME
SECTIONS OF THE ISLAND.

ATLANTIC OCEAN...
IN THE UPPER LEVELS...BROAD SCALE RIDGING COVERS THE AREA W OF
ABOUT 54W...WHILE DEEP UPPER TROUGHING IS E OF 54W WITH AN
ASSOCIATED UPPER LOW DROPPING S NEAR 23N53W. UPPER LEVEL
MOISTURE IS NOTED STREAMING EASTWARD ACROSS THE NORTHERN
PERIPHERY OF THE RIDGE N OF 27N.

AT THE SURFACE...A TIGHT PRESSURE GRADIENT BETWEEN THE GULF OF
MEXICO COLD FRONT THAT STRETCHES NE ACROSS NE FLORIDA TO N OF
THE AREA AT 32N78W AND HIGH PRESSURE TO ITS IS SUPPORTING GALE
FORCE WINDS OVER THE W ATLANTIC N OF 29N E OF THE FRONT TO 73W.
THESE WINDS ARE FORECAST TO LAST UNTIL WED NIGHT. LATEST NWD
RADAR IMAGERY SHOWS A LARGE AREA OF PRECIPITATION CONSISTING OF
MAINLY SCATTERED SHOWERS WITH EMBEDDED ISOLATED TSTMS ACROSS THE
NW PART OF THE BASIN TO THE NW OF A LINE FROM 32N73W SW TO NEAR
MELBOURNE. A STATIONARY FRONT IS OVER THE CENTRAL ATLANTIC ALONG
A POSITION FROM 32N43W TO 28N50W TO 24N59W TO 24N64W. A DECAYING
FRONTAL TROUGH...REMNANTS OF A PREVIOUS COLD FRONT...EXTENDS FROM
28N48W SW TO 23N57W TO THE NE COAST OF THE DOMINICAN REPUBLIC.
SCATTERED SHOWERS ARE WITHIN 90 NM OF THE TROUGH BETWEEN 51W-
59W. ELSEWHERE...A RIDGE EXTENDS FROM STRONG HIGH PRESSURE
CENTERED WELL NE OF THE BASIN SW TO 32N36W TO 29N50W AND TO NEAR
26N69W. THE COLD FRONT IS FORECAST TO REACH FROM NEAR 32N76W TO
THE STRAITS OF FLORIDA WED...AND FROM NEAR BERMUDA TO EASTERN
CUBA WED NIGHT BEFORE BECOMING STATIONARY FROM NEAR 23N65W TO
HISPANIOLA LATE THU NIGHT. SCATTERED SHOWERS AND ISOLATED TSTMS
ARE EXPECTED ALONG AND TO WITHIN ABOUT 60-90 NM E OF THE FRONT
THROUGH WED EVENING WITH MOISTURE CONVERGENCE GUIDANCE
INDICATING THAT THIS ACTIVITY WILL BE CONFINED TO N OF ABOUT 25N
WED AFTERNOON AND NIGHT...AND THEN MAINLY AS SCATTERED SHOWERS
BETWEEN THE SE BAHAMAS AND HISPANIOLA ON THU.

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

$$
AGUIRRE

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