[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151749
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED MAY 15 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 02N37W TO 07N35W MOVING W AT 15 KT.
THE WAVE REMAINS LOW-AMPLITUDE AND EMBEDDED WITHIN THE ITCZ AXIS
COINCIDING WITH A GLOBAL MODEL INDICATED MAXIMUM OF POTENTIAL
VORTICITY AT 315K. TOTAL PRECIPITATABLE WATER AND SATELLITE
IMAGERY ALSO INDICATE A MAXIMUM IN LOW-LEVEL MOISTURE
CONVERGENCE AND CLOUDINESS IN THE VICINITY OF THE WAVE AXIS.
WIDELY SCATTTERED MODERATE CONVECTION IS FROM 03N-08N BETWEEN
32W-39W. THE WAVE IS EXPECTED TO CONTINUE MOVING WESTWARD WITH
PRECIPITATION PROBABILITIES INCREASING BY THE WEEKEND ACROSS THE
WINDWARD ISLANDS.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
07N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N19W TO 04N36W TO THE EQUATOR NEAR 50W. SCATTERED MODERATE AND
ISOLATED STRONG CONVECTION IS FROM 05N-08N BETWEEN 17W-22W.
SCATTERED MODERATE CONVECTION IS FROM 02N-07N BETWEEN 03W-18W...
WITHIN 90 NM EITHER SIDE OF A LINE FROM 01N24W TO 06N32W...AND
FROM 03N-06N BETWEEN 39W-52W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL LOW CENTERED OVER NORTH TEXAS AND
ASSOCIATED SHORTWAVE TROUGH AXIS EXTENDING OVER WEST TEXAS AND
NW MEXICO IS SUPPORTING ONGOING WIDELY SCATTERED SHOWERS AND
ISOLATED TSTMS THIS AFTERNOON ACROSS PORTIONS OF THE NW GULF
NORTH OF 22N WEST OF 93W. THIS ACTIVITY IS LOCATED ON THE
WESTERN PERIPHERY OF A SURFACE RIDGING ANCHORED BY A 1024 MB
HIGH CENTERED NEAR 30N89W. A RIDGE AXIS EXTENDS ALONG 30N INTO
THE SW NORTH ATLC AND TO THE SW INTO A 1021 MB HIGH CENTERED OFF
THE MEXICO COAST NEAR 21N97W. THE RIDGING IS SUPPORTED ALOFT BY
A MIDDLE TO UPPER LEVEL RIDGE AXIS ALONG 88W WHICH IS PROVIDING
FOR OVERALL FAIR CONDITIONS AND CLEAR SKIES W OF 92W. LOOKING
AHEAD...THE RIDGE IS EXPECTED TO REMAIN NEARLY STATIONARY
THROUGH THE REMAINDER OF THE WEEK WITH GENERALLY E-SE WINDS
FORECAST IN THE RANGE OF 10 TO 20 KT.

CARIBBEAN SEA...
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE
WESTERN CARIBBEAN NEAR 15N84W AND IS PROVIDING MUCH OF THE
REMAINDER OF THE CARIBBEAN BASIN WITH DRY NORTHWESTERLY WINDS
ALOFT. WATER VAPOR IMAGERY SHOWS THIS DRY AIR ALOFT E OF 90W
WITH THE EXCEPTION OF MODERATE MIDDLE TO UPPER LEVEL MOISTURE
ASSOCIATED WITH THE SOUTHERN EXTENT OF A TROUGH AXIS OVER THE SW
NORTH ATLC GENERALLY ALONG 65W. THIS MOISTURE TRAILS OVER THE NE
CARIBBEAN...PUERTO RICO...HISPANIOLA...INCLUDING THE ADJACENT
COASTAL WATERS N OF 17N E OF 72W. WIDELY SCATTERED LOW-TOPPED
SHOWERS CONTINUE WITHIN 120 NM EITHER SIDE OF A CORRIDOR FROM
DOMINICA NEAR 15N61W TO SOUTH OF HISPANIOLA NEAR 17N71W.
ELSEWHERE...E-NE TRADES IN THE RANGE OF 10 TO 20 KT ARE
OCCURRING WITH SLIGHTLY HIGHER WIND SPEEDS NOTED WITHIN 120 NM
NORTH OF THE COAST OF COLOMBIA. A COLD FRONT REMAINS ANALYZED
ACROSS PORTIONS OF THE SW NORTH ATLC AND IS FORECAST TO CONTINUE
A WEAKENING TREND AS IT APPROACHES THE NORTH-CENTRAL AND NE
CARIBBEAN OVER THE NEXT 24 TO 36 HOURS.

HISPANIOLA...
CURRENTLY A WEAK PRE-FRONTAL SURFACE TROUGH EXTENDS ACROSS A
PORTION OF THE SW NORTH ATLC AND EXTENDS INLAND OVER CENTRAL
HISPANIOLA TO 19N71W. ISOLATED SHOWERS AND TSTMS ARE EXPECTED
THROUGH THE AFTERNOON AS INSTABILITY INCREASES WITH PEAK DAYTIME
HEATING. MOST OF THE ONGOING SHOWER AND TSTM ACTIVITY IS
OCCURRING OVER THE EASTERN DOMINICAN REPUBLIC AS THE BASE OF A
MIDDLE TO UPPER LEVEL TROUGH IN THE VICINITY OF 20N70W CONTINUES
TO SHIFT SLOWLY EASTWARD OVER THE NEXT 24 TO 36 HOURS. A COLD
FRONT IS ANALYZED WITHIN 150 NM TO THE NORTH OF THE ISLAND...
HOWEVER CONTINUES TO SHOW A WEAKENING TREND ON SATELLITE IMAGERY
AS IT LOSES THE MIDDLE TO UPPER LEVEL SUPPORT ASSOCIATED WITH
THE UPPER LEVEL TROUGH. REMNANT MOISTURE AND CLOUDINESS
ASSOCIATED WITH THE COLD FRONT IS EXPECTED TO IMPACT THE
NORTHERN COAST OF HISPANIOLA BY EARLY WEDNESDAY WITH GREATER
PROBABILITY OF ISOLATED SHOWERS AND TSTMS.

ATLANTIC OCEAN...
MIDDLE TO UPPER LEVEL RIDGING WITH AXIS CURRENTLY OVER THE GULF
OF MEXICO IS PROVIDING MOST OF THE SW NORTH ATLC W OF 65W WITH
DRY NW FLOW ALOFT RESULTING IN MOSTLY CLEAR SKIES AND FAIR
CONDITIONS THIS AFTERNOON. FURTHERMORE...A 1025 MB HIGH IS
CENTERED NEAR 31N75W THAT IS EXPECTED TO SHIFT EASTWARD OVER THE
NEXT 24 TO 36 HOURS. FARTHER EAST...WATER VAPOR IMAGERY
INDICATES A MIDDLE TO UPPER LEVER TROUGH WITH AXIS EXTENDING
INTO THE DISCUSSION AREA NEAR 32N61W TRAILING S-SW TO 25N64W TO
A BASE NEAR 20N70W. THIS TROUGHING SUPPORTS A COLD FRONT
ANALYZED FROM 32N60W TO 25N65W TO EASTERN CUBA NEAR 21N77W. A
PRE-FRONTAL TROUGH IS EXTENDS FROM THE COLD FRONT NEAR 25N64W TO
THE NORTHERN COAST OF HISPANIOLA NEAR 20N71W. WIDELY SCATTERED
SHOWERS AND ISOLATED TSTMS ARE OCCURRING EAST OF THE COLD FRONT
FROM 19N-32N BETWEEN 55W AND THE COLD FRONT BOUNDARY. THE
REMAINDER OF THE CENTRAL AND EASTERN ATLC ARE UNDER THE
INFLUENCE OF SURFACE RIDGING...HOWEVER AN UPPER LEVEL LOW
CENTERED NEAR 30N41W SUPPORTS A SURFACE TROUGH ANALYZED FROM
25N41W TO 32N38W...THAT REMAINS EMBEDDED WITHIN THE SOUTHERN
PERIPHERY OF THE RIDGE. EARLY MORNING ASCAT DATA INDICATES A
STRONG PRESSURE GRADIENT EXISTS AS WINDS N OF 27N REMAIN IN THE
20 TO 30 KT RANGE IN THE VICINITY OF THE SURFACE TROUGH AXIS.
ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM EITHER
SIDE OF A LINE FROM 27N33W TO 32N42W.

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

$$
HUFFMAN


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