[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 010541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON JUN 01 2009

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS LOCATED OVER THE WINDWARD ISLANDS ALONG 61W S
OF 14N MOVING W 15-20 KT. THIS WAVE IS ASSOCIATED WITH A NARROW
MAXIMUM IN TOTAL PRECIPITABLE WATER AHEAD OF DRY LOW-MID LEVEL
AIR IN PART ASSOCIATED WITH SAHARAN DUST. THE POSITION OF THE
WAVE IS BASED MAINLY ON THIS TPW FIELD...AS LITTLE SIGNATURE IS
APPARENT IN THE LOW-MID LEVEL CLOUDS OR IN SFC OBSERVATIONS.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N12W 4N22W 1N40W TO THE EQUATOR
52W. SCATTERED MODERATE CONVECTION IS WITHIN 240 NM EITHER SIDE
OF THE AXIS E OF 22W. SCATTERED MODERATE TO STRONG CONVECTION IS
WITHIN 120 NM N OF THE AXIS BETWEEN 26W-36W.

...DISCUSSION...

GULF OF MEXICO...
THE REMNANTS OF A FRONT ARE MEANDERING OVER THE SE AND S CENTRAL
GULF FROM NEAR NAPLES FLORIDA TO 25N87W TO THE NW CORNER OF THE
YUCATAN PENINSULA. THIS BOUNDARY IS ASSISTING IN PRODUCING
SCATTERED SHOWERS AND TSTMS ALONG AND TO THE S OF THE TROUGH
AXIS. WEAK HIGH PRESSURE IS LOCATED OVER THE N MIDDLE GULF
ALLOWING WINDS TO BE LIGHT AND VARIABLE ACROSS MUCH OF THE N
WATERS AND PROMOTING GENERALLY FAIR WEATHER. MOISTURE INCREASES
OVER THE FAR WRN WATERS IN RESPONSE TO DEEP LAYER TROUGHING OVER
THE WESTERN CONUS. HOWEVER...DOPPLER RADAR AND LIGHTNING DATA
SUGGEST THAT MOST OF THE TSTM ACTIVITY IS LOCATED INLAND OVER
MEXICO AND TEXAS. LOOKING AHEAD A DAY OR TWO...NWP MODELS
SUGGEST THAT THE OLD FRONT WILL GRADUALLY DISSIPATE ALLOWING SFC
RIDGING TO BECOME BETTER ESTABLISHED ACROSS THE AREA.

CARIBBEAN SEA...
THE MID-UPPER PATTERN IS QUITE AMPLIFIED OVER THE CARIBBEAN WITH
A RIDGE OVER THE WRN HALF AND TROUGHING OVER THE ERN HALF.
DIFFLUENCE ALOFT COUPLED WITH LOW-LEVEL CONVERGENCE ALONG A OLD
FRONTAL BOUNDARY OVER THE SE GULF OF MEXICO IS PRODUCING
SCATTERED SHOWERS AND TSTMS OVER THE YUCATAN PENINSULA...YUCATAN
CHANNEL...AND CUBA. SIMILAR ACTIVITY IS OCCURRING OVER PORTIONS
OF CENTRAL AMERICA ENHANCED BY THE ITCZ.  THE ATMOSPHERE IS MORE
STABLE OVER THE CENTRAL CARIBBEAN IN AN UPPER CONFLUENT AREA
BETWEEN THE TROUGH AND RIDGE. SW FLOW ALOFT E OF THE TROUGH AXIS
IS ADVECTING MOISTURE ACROSS THE SE CARIBBEAN...THOUGH IT IS NOT
RESULTING IN ANY SIGNIFICANT SHOWER OR TSTM ACTIVITY. IN THE
LOWER LEVELS...SHORTWAVE IR IMAGERY AND QUIKSCAT DATA SHOW
EVIDENCE OF A WEAK TROUGH OVER AND N OF THE VIRGIN ISLANDS...
GENERATING ISOLATED SHOWERS AND TSTMS IN ITS VICINITY. TRADE
WINDS REMAIN 20-30 KT ACROSS THE S CENTRAL PORTION DUE TO THE
PRESSURE GRADIENT BETWEEN HIGH PRES OVER THE SUBTROPICAL CENTRAL
ATLC AND LOWER PRES OVER NRN SOUTH AMERICA. WINDS NEAR 20 KT ARE
OCCURRING OVER THE TOPOGRAPHICALLY ENHANCED GULF OF HONDURAS.
LITTLE CHANGE IN THESE FLOWS ARE FORECAST OVER THE NEXT COUPLE
OF DAYS.

ATLANTIC OCEAN...
MUCH OF THE ATLC DISCUSSION ZONE IS QUIET TONIGHT...ONLY A FEW
AREAS OF UNSETTLED WEATHER TO MENTION. SCATTERED SHOWERS AND
TSTMS ARE LOCATED OVER THE WRN BAHAMAS ASSOCIATED WITH AN UPPER
JET AND AN OLD FRONTAL BOUNDARY. THE ASSOCIATED THINNING DEBRIS
MOISTURE HAS SPREAD WELL TO THE NE TO BERMUDA. HIGHLY AMPLIFIED
DEEP LAYER RIDGING DOMINATED THE CENTRAL ATLC...THOUGH AN UPPER
LOW AND SFC TROUGH NEAR THE VIRGIN ISLANDS ARE INTERRUPTING THE
RIDGE SLIGHTLY. NONETHELESS...FAIR WEATHER DOMINATES THE
MAJORITY OF THE REGION WITH THE EXCEPTION OF NEAR THE SFC
TROUGH...S OF 22N BETWEEN 61W-66W WHERE ISOLATED SHOWERS AND
TSTMS ARE LIKELY. THE E ATLC IS MAINLY UNDER AN UPPER TROUGH
WITH A RELATED WEAK SFC BOUNDARY EXTENDING FROM 30N25W TO
27N37W. LITTLE SIGNIFICANT SHOWER ACTIVITY IS ALONG THE
BOUNDARY. IN FACT...CONVECTION APPEARS CONFINED TO THE ITCZ.

$$
CANGIALOSI



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