[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 27 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
1730 UTC.

...SPECIAL FEATURE...
TROPICAL STORM DORIAN IS CENTERED NEAR 18.5N 52.1W AT 27/1500
UTC OR ABOUT 626 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING W
AT 20 KT. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45
KT. MINIMUM CENTRAL PRESSURE IS 1011 MB. PLEASE SEE THE LATEST
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
AND THE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34
KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION IS FROM 17N-
20N BETWEEN 50W-55W.

...TROPICAL WAVES...
TROPICAL WAVE IS OVER THE EASTERN TRPCL ATLC WITH AXIS EXTENDING
FROM 17N24W TO 05N27W AND MOVING W-NW NEAR 10 KT. SMALL CLUSTERS
OF MODERATE CONVECTION WITH ISOLATED TSTMS ARE IN THE SOUTHERN
PART OF THE WAVE EMBEDDED WITHIN THE MONSOON TROUGH FROM 06N-09N
BETWEEN 25W-29W. THE REMAINDER WAVE IS EMBEDDED WITHIN A DRY
ENVIRONMENT AS SAL DRY AIR SPREADS OVER IT HINDERING CONVECTION.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E
TROPICAL ATLC NEAR 16N16W AND CONTINUES ALONG 09N24W TO 05N34W.
THE ITCZ AXIS BEGINS NEAR 05N34W AND CONTINUES ALONG 04N44W TO
05N52W. BESIDES THE CONVECTION ALREADY DISCUSSED ASSOCIATED WITH
THE TRPCL WAVE...SCATTERED MODERATE CONVECTION IS FROM 07N-12N
BETWEEN 15W-24W. ISOLATED SHOWERS ARE WITHIN 140 NM N OF THE
AXES BETWEEN 32W-35W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE EXTENDS ACROSS TEXAS INTO THE GULF THEN TO OVER
SOUTHERN FLORIDA PROVIDING MOST OF THE GULF NORTHERLY FLOW
ALOFT. AN UPPER LEVEL CYCLONIC CIRCULATION OVER THE UPPER GREAT
LAKES EXTENDS A BROAD TROUGH ACROSS THE CENTRAL AND EASTERN
CONUS. THIS TROUGH IS SUPPORTING A FRONTAL SYSTEM INLAND FROM
ALABAMA TO LOUISIANA TO TEXAS. AS OF 1600 UTC...A PREFRONTAL
SURFACE TROUGH EXTENDS FROM MISSISSIPPI TO SE LOUISIANA TO
27N95W IN THE GULF. RADAR IMAGERY SHOW RAINSHOWERS AND ISOLATED
TSTMS N OF 29N BETWEEN 91W-94W. SURFACE RIDGING AND ANTICYCLONIC
FLOW IN THE RANGE OF 5-15 KT DOMINATES THE REMAINING GULF
ANCHORED BY A 1017 MB HIGH NEAR 24N88W. WATER VAPOR AND TOTAL
PRECIPITABLE WATER IMAGERY SHOW DRY AIR ACROSS THE BASIN WHICH
IS SUPPORTING FAIR WEATHER.

SURFACE RIDGING WILL PREVAIL ACROSS THE GULF WITHIN THE NEXT 48
HOURS. THE FRONTAL SYSTEM INLAND IS EXPECTED TO MOVE OVER THE
NORTHERN GULF CAUSING RAINSHOWERS ON SUNDAY WHICH WILL
CONCENTRATE OVER THE NE GULF MONDAY AS THE FRONT MOVES EASTWARD.

CARIBBEAN SEA...
A BROAD AND ELONGATED UPPER LEVEL LOW IS CENTERED OVER THE W
ATLC NEAR 21N68W AND EXTENDS INTO THE EASTERN CARIBBEAN
SUPPORTING SCATTERED RAINSHOWERS N OF 11N BETWEEN 64W-68W.
CLUSTERS OF MODERATE CONVECTION WITH EMBEDDED TSTMS ARE OVER THE
SOUTHERN CARIBBEAN S OF 12N INCLUDING COSTA RICA AND PANAMA AND
ASSOCIATED WITH THE MONSOON TROUGH. EXCEPT THE WESTERN CARIBBEAN
W OF 80W...EASTERLY TRADEWINDS UP TO 25 KT ARE ACROSS THE BASIN
WITH THE STRONGEST WINDS BEING OVER THE CENTRAL-SOUTHERN
CARIBBEAN. EXCEPT FOR THE AREAS ALREADY MENTIONED...FAIR WEATHER
CONTINUES OVER THE REMAINDER BASIN BEING SUPPORTED BY DRY AIR IN
THE LOWER AND MIDDLE LEVELS.

TROPICAL STORM DORIAN IS EXPECTED TO WEAKEN INTO A TROPICAL
DEPRESSION LATER TODAY AND PASS AS A REMNANT LOW N OF THE
EASTERN CARIBBEAN ON MONDAY.

HISPANIOLA...
CLEAR SKIES ARE ACROSS THE HISPANIOLA WITH THE EXCEPTION OF THE
NE DOMINICAN REPUBLIC WHERE ISOLATED SHOWERS/TSTMS ARE
CONTINUING ENHANCED BY AN UPPER LEVEL ELONGATED LOW THAT EXTENDS
FROM THE W ATLC OVER THE E CARIBBEAN. AFTERNOON
RAINSHOWERS/TSTMS ARE EXPECTED ACROSS THE ISLAND ASSOCIATED WITH
DAYTIME HEATING AND THE LOW ALOFT. TROPICAL STORM DORIAN IS
EXPECTED TO WEAKEN INTO A TROPICAL DEPRESSION LATER TODAY AND
PASS AS A REMNANT LOW/TRPCL WAVE N OF ISLAND EARLY ON MONDAY.
PRECIPITATION COULD INCREASE AS THE REMNANTS OF THE STORM
APPROACHES THE ISLAND.

ATLANTIC OCEAN...
OVER THE W ATLC...A BROAD UPPER LEVEL TROUGH IS SUPPORTING A
FRONTAL SYSTEM THAT EXTENDS AS A STATIONARY FRONT FROM 30N74W TO
A 1015 MB LOW NEAR 28N78W. A COLD FRONT EXTENDS SW FROM THE LOW
TO 25N79W 23N81W. SCATTERED MODERATE CONVECTION AND ISOLATED
TSTMS ARE OCCURRING N OF 24N W OF 75W. AN ELONGATED UPPER LEVEL
LOW IS SUPPORTING SIMILAR CONVECTION FROM 18N-27N BETWEEN 60W-
67W. OVER THE EASTERN ATLC...A SURFACE TROUGH EXTENDS FROM
30N21W TO 25N28W WITH NO CONVECTION ASSOCIATED WITH IT.
OTHERWISE...BESIDES THE SPECIAL FEATURES ALREADY
DISCUSSED...SURFACE RIDGING AND FAIR WEATHER DOMINATES THE
REMAINDER BASIN.

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

$$
NR


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