[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 07 2015

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.

...SPECIAL FEATURES...
AS OF 07/1500 UTC...A 1007 MB LOW IS CENTERED NEAR 31N78W WITH A
SURFACE TROUGH AXIS EXTENDING FROM THE LOW CENTER TO 27N75W TO
23N76W. THIS LOW IS BEING SUPPORTED IN THE MIDDLE TO UPPER
LEVELS BY A TROUGH THAT EXTENDS FROM THE TENNESSEE VALLEY TO THE
EAST COAST OF FLORIDA. THE LOW HAS BECOME BETTER DEFINED SINCE
WEDNESDAY WITH INCREASING ORGANIZATION OF THUNDERSTORMS
ASSOCIATED WITH THIS SYSTEM. SCATTERED MODERATE CONVECTION IS
WITHIN 200 NM NORTHWEST OF THE LOW CENTER. A BAND OF MODERATE
CONVECTION EXTENDS FROM NORTH TO SOUTH WITHIN 50 NM OF A LINE
FROM 25N71W TO 31N72W. GALE FORCE WINDS WERE REPORTED BY
AIRCRAFT RECONNAISSANCE AND THEREFORE A GALE WARNING HAS BEEN
ISSUED FOR OFFSHORE WATERS WITHIN 60 NM SOUTHWEST OF THE LOW
CENTER. THE LOW IS EXPECTED TO DRIFT GENERALLY NORTHWARD OVER
THE NEXT COUPLE OF DAYS. HEAVY RAIN IS EXPECTED OVER PORTIONS OF
THE COASTAL SOUTHEASTERN UNITED STATES FOR THE NEXT SEVERAL DAYS
REGARDLESS OF WHAT DEVELOPS OUT OF THIS SYSTEM. THE MOST RECENT
TROPICAL WEATHER OUTLOOK GIVES THE CHANCE OF DEVELOPMENT OF THIS
SYSTEM INTO A TROPICAL OR SUBTROPICAL CYCLONE IN THE NEXT 48
HOURS AS HIGH.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
06N23W...WHERE THE ITCZ BEGINS AND CONTINUES THROUGH 03N30W AND
SOUTH OF THE EQUATOR NEAR 39W. SCATTERED MODERATE CONVECTION IS
FROM THE EQUATOR TO 05N BETWEEN 25W AND 49W...AND FROM THE
EQUATOR TO 13N BETWEEN 16W AND 25W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL RIDGE AXIS EXTENDS FROM MEXICO
NORTHEASTWARD OVER THE WESTERN GULF. A MIDDLE TO UPPER LEVEL
TROUGH IS OVER THE SOUTHEASTERN US. NORTHWESTERLY FLOW AND DRY
AIR ALOFT IS OVER THE GULF BASIN BETWEEN THESE TWO FEATURES.
THESE STABLE CONDITIONS COMBINED WITH WEAK HIGH PRESSURE OF 1019
MB CENTERED NEAR 29N85W IS SUPPORTING FAIR WEATHER ACROSS THE
ENTIRE GULF BASIN THIS AFTERNOON. ANTICYCLONIC FLOW AT THE
SURFACE IS OCCURRING AROUND THE SURFACE HIGH...WITH 10 TO 15 KT
EAST TO SOUTHEASTERLY FLOW OVER THE MAJORITY OF THE GULF. VERY
LITTLE CHANGE IS EXPECTED IN WEATHER CONDITIONS OVER THE GULF
OVER THE NEXT 48 HOURS.

CARIBBEAN SEA...
A BROAD MIDDLE TO UPPER LEVEL TROUGH IS CENTERED ALONG 80W OVER
THE CARIBBEAN. GENERALLY DRY AND STABLE CONDITIONS PREVAIL UNDER
THIS TROUGH ACROSS THE BASIN. THE ONLY EXCEPTION IS A NEWLY
IDENTIFIED SURFACE TROUGH THAT EXTENDS FROM NEAR 21N85W TO
HONDURAS NEAR 15N85W. THIS FEATURE WILL BE ADDED TO THE UPCOMING
1800 UTC MAP. ISOLATED MODERATE CONVECTION IS WITHIN 50 NM OF
THE TROUGH AXIS. 15 TO 20 KT TRADE WINDS ARE OVER THE MAJORITY
OF THE BASIN WITH AN AREA OF WINDS TO 25 KT OVER THE CENTRAL
CARIBBEAN FROM THE NORTHERN COAST OF COLOMBIA TO 16N BETWEEN 70W
AND 77W. OVER THE NEXT 24 HOURS THE TROUGH IS EXPECTED TO MOVE
SLOWLY NORTHWEST WITH CONVECTION POSSIBLE FROM THE NORTHERN
COAST OF HONDURAS TO THE YUCATAN PENINSULA. OTHERWISE...FAIR
WEATHER WILL CONTINUE ACROSS THE BASIN.

...HISPANIOLA...
SOUTHWESTERLY FLOW JUST OFF THE SURFACE IS OCCURRING OVER THE
WESTERN HALF OF THE ISLAND ASSOCIATED WITH THE FLOW AROUND THE
LOW PRESSURE SYSTEM OFF THE COAST OF NORTHERN FL/GA. THIS
SOUTHWESTERLY FLOW IS CONVERGING WITH THE EASTERLY TRADE WINDS
TO PRODUCE ISOLATED THUNDERSTORMS OVER THE HIGHER TERRAIN OF THE
WESTERN HALF OF THE ISLAND TODAY. THIS FLOW REGIME MAY CONTINUE
THROUGH SATURDAY AS THE LOW MOVES VERY LITTLE.
THEREFORE...EXPECT ISOLATED THUNDERSTORMS TO REMAIN POSSIBLE
OVER THE WESTERN PORTION OF THE ISLAND THROUGH SATURDAY.

ATLANTIC OCEAN...
THE LOW PRESSURE SYSTEM JUST OFFSHORE NORTHERN FL/GA IS
DISCUSSED IN THE SPECIAL FEATURES SECTION. SURFACE RIDGING
ANCHORED BY A 1026 MB HIGH CENTERED NEAR 30N49W SUPPORTS
ANTICYCLONIC FLOW AND GENERALLY FAIR WEATHER EAST OF 70W AND N
OF 05N OVER THE TROPICAL NORTHERN ATLC. A SURFACE TROUGH IS OVER
THE EASTERN ATLC FROM 30N20W TO 24N32W. THIS TROUGH IS VOID OF
DEEP CONVECTION. OVER THE NEXT TWO DAYS THE LOW WILL MOVE SLOWLY
NORTHWARD WITH ONGOING CONVECTION EXPECTED WITHIN 200 NM OF THE
LOW CENTER...AND SOUTH AND EAST OF THE LOW ASSOCIATED WITH AN
ELONGATED SURFACE TROUGH.

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

$$
LATTO
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