[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070605
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED AUG 07 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...
A TROPICAL WAVE AXIS EXTENDS FROM 19N63W TO 09N64W MOVING W NEAR
5 KT. TOTAL PRECIPITABLE WATER IMAGERY DEPICT A DRY ENVIRONMENT
AHEAD OF IT WHILE MODERATE MOISTURE LIES BEHIND ITS AXIS. DRY
AIR SUBSIDENCE AS WELL AS STRONG DEEP LAYER WIND SHEAR ARE
HINDERING CONVECTION AT THE TIME. THE WAVE IS EXPECTED TO
CONTINUE A WESTWARD TRACK AND BE S OF THE WINDWARD PASSAGE
THURSDAY MORNING.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR
14N17W TO 09N27W 07N33W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
STARTS NEAR 07N33W AND CONTINUES ALONG 07N40W TO 10N46W.
SCATTERED MODERATE CONVECTION IS FROM 07N-17N E OF 20W. SIMILAR
CONVECTION IS FROM 05N-11N BETWEEN 23W-28W AS WELL AS WITHIN 120
NM EITHER SIDE OF THE AXES BETWEEN 29W-40W.

...DISCUSSION...

THE GULF OF MEXICO...
AS OF 0300 UTC...ANTICYCLONIC FLOW IN THE RANGE OF 5-15 KT
SPREADS ACROSS MOST OF THE BASIN ANCHORED BY A 1016 MB HIGH NEAR
25N91W WHICH IS BEING SUPPORTED BY A BROAD MIDDLE TO UPPER LEVEL
RIDGE CENTERED OVER THE NW GULF. A 1018 MB HIGH PRESSURE CENTER
HAS DEVELOPED IN THE NE GULF CENTERED NEAR 30N87W. A STATIONARY
FRONT EXTENDS FROM THE FLORIDA PANHANDLE TO 29N84W 28N82W TO A
1014 MB LOW OVER CENTRAL FLORIDA. A PREFRONTAL TROUGH EXTENDS
FROM THE SAME LOW TO TAMPA BAY TO 26N85W 27N90W. RADAR IMAGERY
SHOW RAINSHOWERS AND ISOLATED TSTMS WITHIN 50 NM OF THE NE GULF
COAST E OF 89W. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE
OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH EXTENDS FROM THE
NORTHERN BAHAMAS TO THE FLORIDA STRAITS TO NEAR 23N84W IN THE SE
GULF. ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE AXIS
AS WELL AS IN THE YUCATAN CHANNEL. OTHERWISE...DRY AIR
SUBSIDENCE IS SUPPORTING FAIR WEATHER OVER THE WESTERN GULF W OF
90W.

THE CENTER OF HIGH PRESSURE IS EXPECTED TO DRIFT NW AND THEN
DISSIPATE EARLY ON THURSDAY. THE SURFACE TROUGH THAT EXTENDS
OVER THE SE GULF IS EXPECTED TO DRIFT WESTWARD AND MOVE TO THE
PENINSULA OF YUCATAN THURSDAY NIGHT. RAINSHOWERS ARE LIKELY TO
CONTINUE OVER THE EASTERN GULF.

THE CARIBBEAN SEA...
AS DEPICTED IN TOTAL PRECIPITABLE WATER AND WATER VAPOR
IMAGERY...DRY AIR SPREADS ACROSS THE BASIN MAINLY S OF 18N
PROVIDING A STABLE...CONVECTION FREE ENVIRONMENT. N OF 18 N...A
MODERATE MOIST ENVIRONMENT AND UPPER LEVEL DIFFLUENCE FROM A
BROAD RIDGE EXTENDING TO THE W CARIBBEAN AND A LOW CENTERED N OF
THE HISPANIOLA ARE ENHANCING SCATTERED MODERATE CONVECTION AND
TSTMS OVER HAITI...NW DOMINICAN REPUBLIC...THE WINDWARD PASSAGE
AS WELL AS BETWEEN SE CUBA AND JAMAICA. A TROPICAL WAVE IS
MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS CURRENTLY JUST E
OF THE VIRGIN ISLANDS. ALL THE LESSER ANTILLES HAS REPORTED
RAINSHOWERS WITHIN THE LAST HOUR ASSOCIATED WITH THE PASSAGE OF
THIS WAVE. TRADEWINDS UP TO 20 KT ARE OVER THE CENTRAL-SOUTHERN
CARIBBEAN NEAR THE COAST OF COLOMBIA WHILE WINDS OF 5-15 KT
DOMINATE ELSEWHERE IN THE BASIN. ISOLATED MODERATE CONVECTION IS
S OF 10N ASSOCIATED WITH THE MONSOON TROUGH AXIS.

WINDS OVER THE CENTRAL-SOUTHERN CARIBBEAN ARE EXPECTED TO
SUBSIDE TO 15 KT WEDNESDAY AFTERNOON. RAINSHOWERS ACTIVITY IS
EXPECTED FOR THE GREATER ANTILLES AND ADJACENT WATERS DURING THE
NEXT 48 HOURS...ASSOCIATED WITH THE WESTWARD PASSAGE OF THE
TROPICAL WAVE AS WELL AS A FAVORABLE UPPER LEVEL SYNOPTIC
PATTERN.

HISPANIOLA...
IN THE UPPER LEVEL...A LOW EXTENDS A TROUGH ACROSS THE ISLAND
FROM THE W ATLC TO THE SW CARIBBEAN. THIS IS SUPPORTING LOW
VALUES OF WIND SHEAR OVER THE ISLAND WHICH ALONG WITH MODERATE
MOISTURE AVAILABILITY AND UPPER LEVEL DIFFLUENCE ARE ENHANCING
SCATTERED MODERATE CONVECTION AND TSTMS OVER HAITI...THE
DOMINICAN REPUBLIC AND THE WINDWARD PASSAGE. RAINSHOWERS ARE
EXPECTED FOR THE ISLAND AND ADJACENT WATERS DURING THE NEXT 48
HOURS...ASSOCIATED WITH THE WESTWARD PASSAGE OF A TROPICAL WAVE
AS WELL AS A FAVORABLE UPPER LEVEL SYNOPTIC PATTERN.

THE ATLANTIC OCEAN...
AS OF 0900 UTC...A DISSIPATING STATIONARY FRONT EXTENDS OVER THE
SW N ATLC FROM 29N74W TO 29N78W TO A 1014 MB LOW OVER CENTRAL
FLORIDA. A PREFRONTAL TROUGH EXTENDS FROM THE NORTHERN BAHAMAS
TO THE FLORIDA STRAITS TO NEAR 23N84W IN THE SE GULF. AT THE
MOMENT THERE IS NO CONVECTION ASSOCIATED EITHER WITH THE TROUGH
OR FRONT. FURTHER EAST...A SURFACE TROUGH FORMERLY PART OF THE
TROPICAL WAVE AXIS IN THE E CARIBBEAN IS MOVING W-NW AROUND THE
PERIPHERY OF A RIDGE WITH AXIS EXTENDING FROM 27N61W TO 23N64W.
SCATTERED MODERATE CONVECTION ASSOCIATED WITH THIS TROUGHINESS
IS FROM 23N-30N BETWEEN 57W-67W. A SURFACE TROUGH IS E OF THE
LESSER ANTILLES FROM 16N56W TO 09N57W WITH SCATTERED MODERATE
CONVECTION FROM 08N-14N BETWEEN 56W-61W. ANOTHER SURFACE TROUGH
ASSOCIATED WITH A 1013 MB LOW EXTENDS FROM 14N51W TO 08N50W WITH
NO CONVECTION ASSOCIATED WITH IT. OTHERWISE...SURFACE RIDGING
AND FAIR WEATHER SUPPORTED BY LOWER-MIDDLE LEVEL DRY AIR
DOMINATE THE REMAINDER BASIN.

A NEW TROPICAL WAVE COULD BE COMING OFF THE WEST AFRICAN COAST
LATER TODAY.

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

$$
RAMOS


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