[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081131
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI FEB 08 2013

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0930 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 5N9W TO
4N15W. THE ITCZ BEGINS AT 4N15W AND CONTINUES TO 3N21W 4N34W
2N45W. SCATTERED MODERATE CONVECTION IS FROM 1N-6N BETWEEN
6W-12W AS WELL AS WITHIN 90 NM S OF THE ITCZ BETWEEN 17W-23W.
ISOLATED MODERATE CONVECTION IS N OF THE ITCZ TO 7N BETWEEN 22W
AND 33W AS WELL AS WITHIN 90 NM N OF THE ITCZ BETWEEN 34W AND
39W.

...DISCUSSION...

GULF OF MEXICO...
A COLD FRONT EXTENDS FROM NEAR CEDAR KEY FLORIDA THROUGH 26N85W
TO 26N90W WHERE IT BECOMES STATIONARY TO 25N96W AND TO 1011 MB
LOW PRES NEAR 19N95W. A SHORTWAVE UPPER TROUGH MOVING THROUGH
THE MID ATLC STATES SUPPORTS THE FRONTAL BOUNDARY ACROSS THE
EASTERN GULF. A PRE-FRONTAL TROUGH EXTENDS AHEAD OF THIS COLD
FRONT FROM JUST S OF TAMPA BAY TO 25N87W. SHOWERS AND
THUNDERSTORMS ARE LOCATED PRIMARILY BETWEEN 26N-27N W OF
IMMOKALEE FLORIDA TO THE TROUGH. A SECOND COLD FRONT IS MAKING
ITS WAY TOWARD THE TEXAS COAST THIS MORNING. THE UPPER LEVEL
IMPETUS FOR THIS FRONT IS EXPECTED TO PHASE WITH THE SHORTWAVE
UPPER TROUGH OVER THE MID ATLC STATES LATER TODAY...USHERING IN
HIGH PRESSURE AT THE SURFACE AND PUSHING THE LEAD COLD FRONT E
OF THE AREA AS THE FRONT CURRENTLY OVER TEXAS DISSIPATES. THE
ENCROACHING RIDGE WILL WEAKEN THE SURFACE LOW OVER THE SW GULF.
NO STRONG WINDS OR PRECIPITATION IS ASSOCIATED WITH THIS LOW.

CARIBBEAN SEA...
STRONG SUBSIDENCE IN PLACE ACROSS THE CARIBBEAN UNDER AN UPPER
RIDGE HAS LIMITED THE LIFT IN THE ATMOSPHERE AND HAMPERED THE
DEVELOPMENT OF SIGNIFICANT CONVECTION OVER THE REGION. TRADE
WIND SHOWERS ARE THE ONLY CONTRIBUTION TO PRECIPITATION IN THE
CARIBBEAN THIS MORNING...WITH MOST OF THE ACTIVITY FOUND E OF
70W. THE CONTINUATION OF A LIGHT PRESSURE GRADIENT IS KEEPING
TRADEWIND FLOW MOSTLY IN THE RANGE OF 10-15 KT WITH ONLY A SMALL
AREA OF 20 KT WINDS ALONG THE COAST OF COLOMBIA. THE UPPER RIDGE
CENTERED OVER THE SW CARIBBEAN WILL BREAK DOWN OVER THE NEXT 48
HOURS AND MAKE WAY FOR THE S END OF THE PHASED UPPER TROUGH
MOVING THROUGH THE GULF OF MEXICO INTO THE NW CARIBBEAN. SOME
SHOWERS ARE POSSIBLE NEAR THIS FRONT OVER THE WEEKEND.

ATLANTIC OCEAN...
THE AFOREMENTIONED SHORTWAVE UPPER TROUGH OVER THE MID ATLC
STATES IS TURING NEGATIVE TILT THIS MORNING...AND ITS ASSOCIATED
SURFACE LOW IS RAPIDLY DEEPENING. A COLD FRONT EXTENDS FROM
THAT LOW OFF THE CAROLINA COAST TO JACKSONVILLE FLORIDA. AS THIS
UPPER TROUGH PHASES WITH THE STRONGER UPPER TROUGH TO ITS W
DESCRIBED IN THE GULF OF MEXICO SECTION...THE COLD FRONT WILL
SWEEP SOUTHEASTWARD THROUGH FLORIDA OVERNIGHT TONIGHT. FRESH TO
STRONG SOUTHERLY FLOW OVER THE NW WATERS WILL SHIFT E AHEAD OF
THE FRONT TODAY. SHOWER ACTIVITY AHEAD OF THE FRONT IS WANING AS
THE SURFACE LOW ANCHORING THE FRONT AND ITS MID-LEVEL IMPETUS
PROGRESS N AWAY FROM THE FORECAST AREA...TAKING THE BULK OF THE
AVAILABLE MOISTURE WITH THEM. FARTHER EAST IN THE ATLC...THE
TAIL END OF A STATIONARY FRONT IS ALONG 32N54W TO 27N58W. NO
SHOWERS ARE ASSOCIATED WITH THIS FRONTAL BOUNDARY AT THIS TIME.
OVER THE CENTRAL ATLC...A SURFACE TROUGH EXTENDS SW ALONG 30N48W
TO 22N57W. WIDELY SCATTERED SHOWERS CAN BE FOUND WITHIN 90 NM OF
THIS TROUGH PRIMARILY S OF 25N. BOTH THE WEST ATLC STATIONARY
FRONT AND THE CENTRAL ATLC TROUGH ARE BEING SUPPORTED BY A WEAK
UPPER TROUGH N OF 20N BETWEEN 50W AND 60W. THE EAST ATLC IS
DOMINATED BY SURFACE RIDGING EXTENDING FROM A 1033 MB HIGH NEAR
42N20W...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE ENTIRE
EASTERN ATLC WITH MAINLY MODERATE NE TRADE WINDS.

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

$$
SCHAUER/NR



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