[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110557
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU JUL 11 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 09N28W TO 16N26W MOVING W AT 10-15
KT. THE WAVE REMAINS EMBEDDED WITHIN THE MONSOON TROUGH AND ITCZ
AXIS COINCIDING WITH A GLOBAL MODEL INDICATED 700 MB TROUGH AND
ASSOCIATED VORTICITY MAXIMUM IN THE VICINITY OF 14N27W. TOTAL
PRECIPITABLE WATER IMAGERY SHOWS A RELATIVE MOISTURE MAXIMUM
FROM 10N-16N BETWEEN 23W-33W. ISOLATED MODERATE CONVECTION IS
FROM 09N-15N BETWEEN 25W-29W.

TROPICAL WAVE EXTENDS FROM 06N43W TO 12N39W MOVING W AT 10 KT.
THE WAVE REMAINS ON THE WESTERN EXTENT OF THE ITCZ AXIS WITH LOW-
LEVEL STREAMLINE ANALYSIS INDICATING CYCLONIC TURNING OF THE LOW-
LEVEL WIND FIELD VERTICALLY THROUGH 700 MB S OF 14N BETWEEN 38W-
45W. A SAHARAN AIR LAYER REMAINS ON THE NORTHERN PERIPHERY OF
THE WAVE AXIS AND THIS IS RESULTING IN LIMITED CONVECTION AT
THIS TIME. ISOLATED MODERATE CONVECTION IS FROM 06N-09N BETWEEN
39W-43W.

TROPICAL WAVE EXTENDS FROM 15N73W TO 23N73W MOVING W-NW AT 15-20
KT. THE WAVE...REMNANTS OF CHANTAL...CONTINUES AS AN OPEN WAVE
WITH NO DEFINED LOW-LEVEL CIRCULATION CENTER. PLENTY OF LOW-
LEVEL MOISTURE CONVERGENCE AND MID-LEVEL VORTICITY ARE AIDING IN
GENERATING SCATTERED MODERATE CONVECTION FROM 16N-24N BETWEEN
68W-75W...INCLUDING MUCH OF HISPANIOLA AND PORTIONS OF THE
WINDWARD PASSAGE. THE WAVE IS EXPECTED TO TRACK TOWARDS THE
FLORIDA STRAITS AND SOUTHERN FLORIDA PENINSULA OVER THE WEEKEND.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO
11N20W TO 13N24W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 13N27W TO 09N41W. SCATTERED MODERATE CONVECTION IS
FROM 08N-14N BETWEEN 15W-19W. ISOLATED MODERATE CONVECTION IS
WITHIN 150 NM NORTH AND 210 NM SOUTH OF THE ITCZ AXIS BETWEEN
29W-40W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY INDICATES EAST-NORTHEASTERLY UPPER LEVEL
FLOW NORTH OF A BROAD TROUGH AXIS EXTENDING FROM AN UPPER LEVEL
LOW CENTERED OVER THE FLORIDA STRAITS NEAR 23N80W TO OVER EAST-
CENTRAL MEXICO NEAR 23N101W. MOSTLY DRY AND STABLE AIR ALOFT IS
NOTED OVER THE NORTHERN GULF WATERS THIS EVENING WHILE A SURFACE
RIDGE ANCHORED BY A 1018 MB HIGH CENTERED NEAR 28N91W LIES
BENEATH PROVIDING FOR OVERALL TRANQUIL CONDITIONS. A SLIGHT
WEAKNESS IN THE RIDGE IS ANALYZED AS A SURFACE TROUGH FROM SE
GEORGIA NEAR 32N82W TO THE TAMPA BAY REGION TO 26N84W IN THE FAR
EASTERN GULF. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE
OCCURRING FROM 27N-29N BETWEEN 82W-85W. ACROSS PORTIONS OF THE
FAR SE GULF AND SW GULF...WITHIN MOSTLY WESTERLY FLOW ALOFT ON
THE SOUTHERN PERIPHERY OF THE UPPER LEVEL TROUGHING...MIDDLE TO
UPPER LEVEL MOISTURE INCREASES WITH ISOLATED SHOWERS OCCURRING S
OF 24N...AND MORE AREAL COVERAGE OF SHOWER AND TSTM ACTIVITY
ACROSS INLAND SOUTHERN MEXICO AND THE YUCATAN PENINSULA THIS
EVENING. LOOKING AHEAD...THE WEAKNESS IN THE SURFACE RIDGING
BETWEEN THE SW NORTH ATLC AND GULF WILL PROVIDE FOR THE REMNANTS
OF CHANTAL TO TRACK W-NW THROUGH THE WEEKEND ACROSS THE FLORIDA
STRAITS AND SOUTHERN FLORIDA PENINSULA.

CARIBBEAN SEA...
THE PRIMARY FOCUS FOR THE CARIBBEAN IS THE REMNANTS OF
CHANTAL...ANALYZED AS AN OPEN TROPICAL WAVE ALONG 73W. MUCH OF
THE CONVECTION ASSOCIATED WITH THE WAVE IS LOCATED ON THE
EASTERN PERIPHERY DUE TO UPPER LEVEL WESTERLY SHEAR TO THE NW
OVER THE FLORIDA STRAITS. SCATTERED TO NUMEROUS SHOWERS AND
SCATTERED TSTMS ARE OCCURRING N OF 14N BETWEEN 66W-76W...
INCLUDING HISPANIOLA AND PORTIONS OF THE WINDWARD PASSAGE AND
EASTERN CUBA. THE WAVE AND AREA OF MOISTURE IS EXPECTED TO TRACK
W-NW OVER THE NEXT 24 TO 36 HOURS PROVIDING INCREASED RAINFALL
CHANCES FOR HISPANIOLA AND CUBA THROUGH THE WEEKEND. OVER THE
WESTERN CARIBBEAN...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS
CENTERED OVER NICARAGUA NEAR 12N85W. MIDDLE TO UPPER LEVEL
MOISTURE REMAINS ACROSS MUCH OF CENTRAL AMERICA AND THE NW
CARIBBEAN THIS EVENING WITH UPPER LEVEL DIFFLUENCE CONTINUING TO
GENERATE ISOLATED SHOWERS AND TSTMS S OF 21N W OF 83W. FARTHER
SOUTH ACROSS THE SW CARIBBEAN...THE MONSOON TROUGH AXIS EXTENDS
ALONG 10N FROM NORTHERN COLOMBIA TO NORTHERN COSTA RICA AND IS
PROVIDING FOCUS FOR WIDELY SCATTERED SHOWERS AND TSTMS S OF 12N
BETWEEN 73W-86W. AS THE REMNANTS OF CHANTAL TRACK NORTH OF BASIN
OVER THE WEEKEND...THE BEGINNING OF NEXT WEEK WILL SEE A RETURN
TO E-SE TRADES IN THE RANGE OF 10 TO 20 KT WITH STRONGER WINDS
POSSIBLE IN THE VICINITY OF THE NORTHERN COLOMBIA COAST.

HISPANIOLA...
CURRENTLY A TROPICAL WAVE...THE REMNANTS OF CHANTAL...ARE
PRODUCING SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS ACROSS
THE ISLAND THIS EVENING. SOME OF THIS RAINFALL IS LOCALLY HEAVY
WITH THE POTENTIAL FOR LOCALIZED FLOODING. THE TROPICAL WAVE IS
EXPECTED TO MOVE W-NW OVER THE NEXT 24 TO 36 HOURS AND
CONDITIONS ACROSS HISPANIOLA ARE EXPECTED TO GRADUALLY IMPROVE
BY LATE FRIDAY INTO EARLY SATURDAY. THEREAFTER...E-SE TRADES
WILL RESUME ACROSS THE REGION WITH THE MORE TYPICAL AFTERNOON
SHOWERS AND TSTMS OCCURRING ACROSS THE ISLAND DURING THE WEEKEND
INTO EARLY NEXT WEEK.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE FLORIDA STRAITS
NEAR 24N80W THAT IS PROVIDING THE SW NORTH ATLC WITH A WEAKNESS
IN THE SURFACE RIDGING TO DRAW THE REMNANTS OF CHANTAL W-NW FROM
THE NORTH-CENTRAL CARIBBEAN SEA AND HISPANIOLA ACROSS THE
BAHAMAS AND SOUTH FLORIDA THROUGH THE UPCOMING WEEKEND.
CURRENTLY ANALYZED AS A TROPICAL WAVE ALONG 73W...SCATTERED
SHOWERS AND TSTMS ARE OCCURRING S OF 25N BETWEEN 68W-75W...
INCLUDING THE TURKS AND CAICOS ISLANDS. SURFACE RIDGING ANCHORED
BY A 1022 MB HIGH CENTERED IN THE VICINITY OF BERMUDA NEAR
33N64W WILL GRADUALLY WEAKEN OVER THE NEXT 24 TO 36 HOURS AND
ALLOW THE WAVE TO MAKE ITS WAY TOWARDS THE FLORIDA PENINSULA AND
AREAS OFF THE EASTERN COASTLINE. FARTHER EAST...AN UPPER LEVEL
LOW IS CENTERED NEAR 31N55W THAT REMAINS AT THE SOUTHWESTERN
EXTENT OF A STATIONARY FRONT ANALYZED FROM 36N40W TO 31N49W.
MOISTURE ASSOCIATED WITH THE UPPER LEVEL LOW IS GENERATING
ISOLATED SHOWERS FROM 23N-32N BETWEEN 49W-57W. GLOBAL MODELS
INDICATE THIS UPPER LEVEL FEATURE WILL RETROGRADE AND DRIFT
WESTWARD ACROSS THE SW NORTH ATLC OVER THE COMING DAYS.
FINALLY...THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE
RIDGE ANCHORED BY A 1021 MB HIGH CENTERED SW OF THE AZORES NEAR
35N32W. A SAHARAN AIR LAYERS CONTINUES TO BE THE OVERALL
DOMINATE FEATURE PROVIDING FAIRLY STABLE CONDITIONS N OF 18N E
OF 47W.

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

$$
HUFFMAN


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