[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162353
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUL 16 2011

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
2315 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ANALYZED FROM 10N22W TO 17N21W MOVING W AT
15-20 KT. EXAMINING RECENT HOVMOLLER DIAGRAM DATA AND THE UPPER
AIR TIME SECTION ANALYSES...IT INDICATES THE WAVE PASSED DAKAR
SENEGAL AROUND 15/1200 UTC. GLOBAL MODEL DATA ALSO INDICATES THE
WAVE AXIS COINCIDES WITH AN 850-700 MB LOWER ATMOSPHERIC TROUGH
THAT IS FORECAST TO DRIFT WESTWARD OVER THE NEXT COUPLE OF DAYS.
CURRENTLY CONVECTION REMAINS LIMITED TO ISOLATED MODERATE ALONG
THE W AFRICA COAST FROM 09N-15N BETWEEN 15W-19W.

TROPICAL WAVE IS ANALYZED FROM 10N41W TO 18N44W MOVING W AT
15-20 KT. THE WAVE IS FAIRLY BROAD COVERING A LARGE PORTION OF
THE CENTRAL ATLC THIS EVENING AND ALSO COINCIDES WITH A 700 MB
TROUGH WITH AXIS ALONG 44W. MOSTLY DRY CONDITIONS ARE NOTED AT
THE SURFACE AND ALOFT...WHICH IS PROVIDING FOR ONLY LOW-LEVEL
CLOUDINESS AND A LACK OF ANY CONVECTION. THE CIMSS SAHARAN AIR
LAYER TRACKING PRODUCT SHOWS A STRONG DUST LAYER FOLLOWS TO THE
EAST OF THE WAVE AXIS TO THE WEST OF THE WAVE MENTIONED ABOVE.

TROPICAL WAVE IS ANALYZED FROM 08N58W TO 13N54W MOVING W AT
15-20 KT. THE WAVE IS LOCATED IN THE VICINITY OF THE LEADING
EDGE OF A ENHANCED LOW-LEVEL MOISTURE AS DEPICTED ON TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS
FROM 11N-15N BETWEEN 51W-58W.

TROPICAL WAVE IS ANALYZED FROM 18N93W TO 23N91W IN THE SW GULF
OF MEXICO MOVING W AT 15-20 KT. THE WAVE HAS BECOME DIFFICULT TO
DISCERN AND IS EXPECTED TO BECOME DIFFUSE OVER THE NEXT 24 HOURS
AS IT APPROACHES THE EASTERN MEXICO COAST. TOTAL PRECIPITABLE
WATER SHOWS THAT LOW-LEVEL MOISTURE IS ENHANCED IN THE VICINITY
OF THE WAVE ACROSS THE SW GULF S OF 23N AND IS GENERATING A FEW
ISOLATED AREAS OF SCATTERED MODERATE CONVECTION...ONE OVER THE
YUCATAN PENINSULA FROM 17N-21N BETWEEN 88W-92W AND THE OTHER
FROM 21N-24N BETWEEN 96W-98W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 21N17W
THEN RESUMES WEST OF THE TROPICAL WAVE ALONG 22W NEAR 09N24W TO
07N32W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N32W TO 05N53W. ISOLATED MODERATE CONVECTION IS FROM 03N-06N
BETWEEN 47W-51W.

...DISCUSSION...

GULF OF MEXICO...
AN LARGE AND EXPANSIVE UPPER LEVEL ANTICYCLONE IS CENTERED OVER
THE CENTRAL CONUS AND THE SOUTHERN PERIPHERY OF THIS RIDGE
EXTENDS SOUTHWARD ACROSS THE NORTHERN GULF WATERS NORTH OF 25N.
WATER VAPOR IMAGERY INDICATES MIDDLE TO LOW-LEVEL MOISTURE
EXTENDS FROM THE W ATLC WATERS EASTWARD ACROSS NORTHERN FLORIDA
AND THE NORTHERN GULF COAST ALONG 30N TO EASTERN TEXAS. WEAK
TROUGHING ALSO EXTENDS ALONG THE EASTERN SEABOARD SW OF THE
CAROLINAS AND IS SUPPORTIVE OF A FRONTAL TROUGH FROM CAPE
CANAVERAL TO 29N85W THEN INLAND TO A 1012 MB LOW CENTERED OVER
SW ALABAMA. LOW-LEVEL CONVERGENCE AND PEAK DAYTIME INSTABILITY
IS SUPPORTING SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS
ACROSS THE SOUTHERN FLORIDA PENINSULA AND NE GULF N OF 28N.
ELSEWHERE...BRIDGED BETWEEN THE TROPICAL WAVE MENTIONED ABOVE
ACROSS THE SW GULF S OF 23N AND THE FRONTAL TROUGHING ACROSS THE
NE GULF...A SURFACE RIDGE AXIS EXTENDS FROM THE FLORIDA KEYS TO
NEAR GALVESTON TEXAS ANCHORED ON A 1017 MB HIGH CENTERED NEAR
27N87W. E-SE WINDS ARE EXPECTED TO REMAIN DOMINATE OVER MUCH OF
THE GULF THROUGH THE TUESDAY AS THE SURFACE RIDGING HOLDS ALONG
27N.

CARIBBEAN SEA...
BROAD UPPER LEVEL CYCLONIC FLOW COVERS MUCH OF THE CARIBBEAN
WITH PRIMARILY NORTHEASTERLY FLOW W OF 63W. THE UPPER LEVEL LOW
IS CENTERED OVER ARUBA AND CONTINUES TO GENERATE WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS IN THE VICINITY OF THE MONA
PASSAGE...EASTERN HISPANIOLA FROM 18N-20N BETWEEN 71W-75W...AND
ALONG THE SOUTHERN COAST OF CUBA BETWEEN 77W-82W. E TO SE
SURFACE WINDS GENERALLY IN THE 15-20 KT RANGE ARE EXPECTED
ACROSS MUCH OF THE WATERS THROUGH THE OVERNIGHT PERIOD INTO
SUNDAY. AN APPROACHING TROPICAL WAVE CURRENTLY SE OF THE
WINDWARD ISLANDS ALONG 56W WILL INCREASE PRECIPITATION CHANCES
FOR THE EASTERN CARIBBEAN THROUGH MONDAY AND CONTINUE WESTWARD
THROUGH THE REMAINDER OF THE UPCOMING WEEK. ELSEWHERE THIS
EVENING...SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER INLAND
PORTIONS OF CENTRAL AMERICA AS AN ACTIVE MONSOON TROUGH IN THE
EAST PACIFIC REGION CONTINUES TO GENERATE LOCALLY HEAVY RAINFALL
ACROSS WESTERN PANAMA...COSTA RICA...NICARAGUA...AND HONDURAS.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY INDICATES A LONGWAVE TROUGH IS LOCATED OFF
THE NEW ENGLAND AND MID-ATLC COAST WITH AXIS ALONG 65W THAT
EXTENDS SOUTHWARD TO 30N...WITH INFLUENCE BETWEEN 60W-82W. ALONG
THE SOUTHERN PERIPHERY OF THIS TROUGH...MIDDLE TO LOW-LEVEL
MOISTURE CONTINUES TO POOL ALONG A STATIONARY BOUNDARY ANALYZED
FROM 32N58W W-SW ALONG 29N65W TO A 1014 MB LOW CENTERED NEAR
29N79W. A FRONTAL TROUGH CONTINUES WESTWARD ACROSS FLORIDA FROM
CAPE CANAVERAL INTO THE NE GULF OF MEXICO WATERS NEAR 28N83W.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 180 NM
EITHER SIDE OF THE FRONT. THE REMAINDER OF THE CENTRAL AND
EASTERN ATLC CONTINUES TO BE UNDER THE INFLUENCE OF A SURFACE
RIDGE WITH AXIS ALONG 32N42W TO 25N57W THEN WESTWARD TO 24N70W.
WITH THE EXCEPTION OF THE TROPICAL WAVE ALONG 44W PERTURBING THE
SURFACE FLOW...MOSTLY NE WINDS OF 20 KT ARE OCCURRING EAST OF
THE RIDGE AXIS.

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

$$
HUFFMAN




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