[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 271747
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN JUL 27 2008

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.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 32W/33W S OF 20N MOVING W 15-20 KT. THIS
LARGE WAVE ENCOMPASSES A BROAD AREA OF LOW-LEVEL CYCLONIC
TURNING THAT COVERS WELL OVER A 10 DEGREE AREA OF LONGITUDE WITH
A MID-LEVEL FOCUSED VORTICITY MAXIMUM ALONG THE AXIS NEAR 14N.
EVEN WITH THE MODEST AMPLIFICATION...DEEP CONVECTION IS ABSENT.

TROPICAL WAVE IS ALONG 50W S OF 25N MOVING W 10-15 KT. AN
EARLIER QUIKSCAT PASS CONFIRMS POSITION OF THE WAVE AND THAT
DESPITE HIGH AMPLITUDE WAVE EXHIBITS NO ORGANIZED AREAS OF
CONVECTION AS IT MOVES UNDER AN AREA OF STRONG SUBSIDENCE ALOFT.
NORTHERN BRANCH OF WAVE HAS BROKEN OFF AND IS ANALYZED AS A
SURFACE TROUGH WHICH IS BEING STEERED NORTHWARD DUE TO WRN ATLC
UPPER LEVEL TROUGHING.

TROPICAL WAVE IS ALONG 79W/80W S OF 20N MOVING W NEAR 15-20 KT.
LITTLE SIGNATURE IS OBSERVED ON SATELLITE IMAGERY AND AN EARLIER
QUIKSCAT PASS SUGGESTS SLIGHT WEAK CYCLONIC TURNING WEST OF
JAMAICA. THE MIMIC TPW PRODUCT FROM CIMSS SHOWS A WEAK AND QUICK
MOVING MOISTURE SURGE ASSOCIATED WITH THIS FEATURE. SCATTERED
MODERATE CONVECTION IS ACROSS PANAMA...COSTA RICA AND THE SW
CARIBBEAN SEA S OF 11N BUT IS MOST LIKELY DUE TO AN UPPER
DIFFLUENT PATTERN AND CLOSE PROXIMITY TO THE ITCZ.

 ...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 12N13W 15N25W 13N31W 10N35W 5N44W
6N49W 11N 54W AND INTO ERN VENEZUELA NEAR 9N61W. CLUSTER OF
WIDELY SCATTERED MODERATE CONVECTION IS ALONG THE W AFRICAN
COAST AND EXTENDS FROM 4N-11N BETWEEN 10W-19W. SCATTERED
MODERATE CONVECTION IS FROM 6N-11N BETWEEN 38W-40W. SIMILAR
CONVECTION IS FROM 9N-12N BETWEEN 56W-62W.

...DISCUSSION...

GULF OF MEXICO...
STRONG NE TO E MID TO UPPER LEVEL FLOW RESIDES ON THE SRN
PERIPHERY OF AN UPPER RIDGE CENTERED OVER W TEXAS AND SRN NEW
MEXICO. THIS UPPER FLOW LIES N OF 21N AND IS ADVECTING A FAIR
AMOUNT OF HIGH CLOUDINESS ACROSS THE NE AND NORTH CENTRAL GULF.
AT THE SURFACE A WEAK TROUGH EXTENDS FROM NORTH OF TALLAHASSEE
FLORIDA SW INTO THE NE GULF NEAR 28N87W. THIS FORCING MECHANISM
COUPLED WITH A DIFFLUENT PATTERN ALOFT IS GENERATING SCATTERED
SHOWERS AND TSTMS ACROSS THE GULF N OF 27N BETWEEN THE BIG BEND
OF FLORIDA TO 92W. ALSO SCATTERED SHOWERS AND ISOLATED TSTMS ARE
OVER THE FLORIDA KEYS EXTENDING SW INTO WRN PORTIONS OF THE
FLORIDA STRAITS. ELSEWHERE...A PAIR OF SURFACE HIGHS COVER THE
REMAINDER OF THE GULF W OF 92W WITH A 1016 MB HIGH CENTERED NEAR
27N91W AND A 1019 MB HIGH CENTERED NEAR VERACRUZ MEXICO. THESE
TWO ANTICYCLONIC CIRCULATIONS ARE ALLOWING WINDS TO BE LIGHT
VARIABLE ACROSS MUCH OF THE AREA.

CARIBBEAN SEA...
UPPER LEVEL TROUGHING EXTENDS FROM THE W ATLC ACROSS CUBA...
JAMAICA AND HISPANIOLA WHILE AN UPPER LEVEL HIGH IS LOCATED OVER
NRN NICARAGUA AND HONDURAS. THESE TWO FEATURES ARE PRODUCING
N-NW FLOW OVER THE WRN CARIBBEAN W OF 76W. AMPLE MIDDLE TO UPPER
LEVEL MOISTURE IS ACROSS THE GREATER ANTILLES N OF 17N AND IS
GENERATING SCATTERED SHOWERS/ISOLATED TSTMS ACROSS CUBA
HISPANIOLA AND THE WINDWARD PASSAGE. A SMALL UPPER LOW IS
LOCATED NEAR THE SRN WINDWARD ISLANDS DRAWING MID-HIGH LEVEL
CLOUDINESS ACROSS THE ANTILLES S OF 13N AND SCATTERED MODERATE
CONVECTION ACROSS TRINIDAD AND TOBAGO. ELSEWHERE...WATER VAPOR
IMAGERY SHOWS WIDESPREAD STRONG TO MODERATE DRY AIR WHICH IS
SUPPRESSING THE DEVELOPMENT OF ANY DEEP CONVECTIVE ACTIVITY...
WITH EXCEPTION TO THE ITCZ CONVECTION WHICH SKIRTS THE SW WATERS
S OF 11N. TRADE WINDS REMAIN STRONG OVER THE S CENTRAL WATERS
BUT OTHERWISE REMAIN LIGHT TO MODERATE ACROSS THE REMAINDER OF
THE REGION.

ATLANTIC OCEAN...
A LARGE UPPER LOW CENTERED NEAR 27N66W WITH ASSOCIATED TROUGHING
EXTENDS SW ACROSS CUBA AND THE WINDWARD PASSAGE PRODUCING
DISORGANIZED WIDELY SCATTERED SHOWERS AND TSTMS W OF 63W.
MID-UPPER RIDGING CONTROLS THE REMAINDER OF THE ATLC DISCUSSION
AREA WITH AN UPPER HIGH CENTERED NEAR 21N29W. S TO SE UPPER FLOW
ON THE WRN PERIPHERY OF THIS RIDGE IS PRODUCING UNFAVORABLE
CONDITIONS N OF THE TROPICAL WAVE ALONG 50W. A SURFACE TROUGH IS
ANALYZED FROM 31N43W TO 26N48W GENERATING SCATTERED SHOWERS AND
POSSIBLE ISOLATED EMBEDDED TSTMS FROM 26N-31N BETWEEN 43W-49W.
BESIDES FOR THAT AREA OF CONVECTION ASSOCIATED WITH THE
TROUGH...MUCH OF THE CENTRAL AND ERN ATLC IS VOID OF DEEP
CLOUDINESS. AT THE SURFACE STRONGER AREAS OF WIND ARE OBSERVED
NEAR THE TROPICAL WAVES...DUE TO THE TIGHTENED PRESSURE PATTERN
BETWEEN THOSE LOW PRESSURE FEATURES AND A QUASI-STATIONARY
1027 MB BERMUDA-AZORES HIGH CENTERED NEAR 38N43W.

$$
HUFFMAN


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