[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171201
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE SEP 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...
FORMER TROPICAL DEPRESSION INGRID DISSIPATED OVER THE MOUNTAINS
OF EASTERN MEXICO NEAR 17/0900 UTC. THE REMNANTS OF INGRID WERE
LOCATED NEAR LATITUDE 23.7N 99.9W AND WERE MOVING WESTWARD AT 4
NM. MAXIMUM SUSTAINED WINDS DECREASED TO NEAR 20 KT WITH HIGHER
GUSTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. HEAVY
RAINFALL AND FLOODING STILL POSSIBLE. PLEASE READ THE PUBLIC
ADVISORIES ABOUT INGRID THAT ARE ISSUED UNDER WMO HEADER WTNT35
KNHC AND UNDER AWIPS HEADER MIATCPAT5...AND THE FORECAST/
ADVISORIES THAT ARE ISSUED UNDER WMO HEADER WTNT25 KNHC AND
UNDER AWIPS HEADER MIATCMAT5. CURRENTLY...SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS ARE OVER EASTERN MEXICO FROM 19N-
26N BETWEEN 95W-101W.

THE CENTER OF TROPICAL STORM HUMBERTO AT 17/0900 UTC IS NEAR
27.8N 42.7W OR ABOUT 998 NM W-SW OF THE AZORES. ITS PRESENT
MOVEMENT IS N-NE AT 4 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE
IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 35 KNOTS WITH
GUSTS TO 45 KNOTS. PLEASE READ THE PUBLIC ADVISORIES ABOUT
HUMBERTO THAT ARE ISSUED UNDER WMO HEADER WTNT34 KNHC AND UNDER
AWIPS HEADER MIATCPAT4... AND THE FORECAST/ADVISORIES THAT ARE
ISSUED UNDER WMO HEADER WTNT24 KNHC AND UNDER AWIPS HEADER
MIATCMAT4. PRESENTLY...SCATTERED MODERATE CONVECTION AND TSTMS
ARE N-NE OF THE LOW CENTER FROM 27N-32N BETWEEN 39W-45W.

A BROAD AREA OF LOW PRESSURE IS OVER THE EASTERN YUCATAN
PENINSULA ASSOCIATED WITH A SURFACE TROUGH AND A 1007 MB LOW
PRESSURE CENTER. THE TROUGH AXIS EXTENDS FROM 21N87W TO THE LOW
NEAR 17N88W TO 15N88W. THIS DISTURBANCE IS PRODUCING NUMEROUS
STRONG CONVECTION FROM 16N-19N W OF 86W. WIDESPREAD MODERATE/
ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 15N-23N W OF 77W.
THIS CONVECTION IS BEING SUPPORTED BY VERY MOIST AIR IN THE
REGION AS WELL AS DIFFLUENT FLOW ALOFT FROM AN UPPER-LEVEL
TROUGH OVER THE SE GULF AND A WEAK RIDGE THAT EXTENDS FROM THE
BAHAMAS TO THE CENTRAL CARIBBEAN SEA. THE LOW IS FORECAST TO
MOVE SLOWLY TOWARD THE WEST-NORTHWEST AND EMERGE OVER THE BAY OF
CAMPECHE TONIGHT OR WEDNESDAY. ENVIRONMENTAL CONDITIONS ARE
EXPECTED TO BE A LITTLE MORE FAVORABLE FOR DEVELOPMENT DURING
THE NEXT DAY OR TWO...AND THE LOW HAS A MEDIUM CHANCE OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. IT IS
LIKELY THAT THE LOW IS WILL DRIFT TOWARD THE WEST-
NORTHWEST...ACROSS THE SOUTHWESTERN GULF OF MEXICO LATER IN THE
WEEK. ENVIRONMENTAL CONDITIONS SHOULD CONTINUE TO BE GENERALLY
CONDUCIVE FOR SOME ADDITIONAL DEVELOPMENT DURING THAT TIME. THIS
SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 5 DAYS.

...TROPICAL WAVES...
A TROPICAL WAVE IS MOVING ACROSS THE CAPE VERDE ISLANDS. IT AXIS
EXTENDS FROM 19N21W TO 09N27W AND IS MOVING W NEAR 5 KNOTS.
TOTAL PRECIPITABLE WATER IMAGERY AND METEOSAT SATELLITE IMAGERY
SHOW THAT DRY AIR INTRUSION TO THE WAVE ENVIRONMENT OCCURRED
WITHIN THE LAST COUPLE OF HOURS. DEEP CONVECTION CONTINUE TO BE
SUPPRESSED. SCATTERED MODERATE CONVECTION DEVELOPED WITHIN 170NM
NE OF THE WAVE AXIS FROM 16N-20N...CONCURRING WITH A SMALL AREA
OF MODERATE TO HIGH MOIST AIR IN THE TOTAL PRECIPITABLE WATER
IMAGERY.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH PASSES THROUGH COASTAL W AFRICA NEAR 12N16W
TO 11N24W TO 09N33W. THE ITCZ CONTINUES FROM 09N33W TO 10N46W TO
10N59W. SCATTERED MODERATE CONVECTION IS FROM 07N-10N BETWEEN
23W-32W. SIMILAR CONVECTION WITH ISOLATED TSTMS IS FROM 05N-10N
BETWEEN 39W-44W AS WELL AS FROM 10N-13N BETWEEN 44W-62W.

...DISCUSSION...

THE GULF OF MEXICO...
ADVECTION OF VERY MOIST AIR FROM THE WEST CARIBBEAN SEA
CONTINUES TO MOVE ACROSS THE YUCATAN PENINSULA TO THE WESTERN
GULF SUPPORTING THE CONVECTION ASSOCIATED WITH THE REMNANTS OF
INGRID. MIDDLE-LEVEL DIFFLUENCE OVER THE EASTERN GULF SUPPORTS
THIS CONVECTION TOO. SEE THE SPECIAL FEATURES SECTION ABOVE FOR
MORE INFORMATION ABOUT THE REMNANTS OF INGRID. SCATTERED
MODERATE CONVECTION FROM INGRID EXTENDS TO THE WESTERN GULF
WATERS S OF 28N W OF 95W. THE BASE OF AN UPPER-LEVEL TROUGH IS
OVER THE SE GULF JUST W OF A WEAK RIDGE THAT EXTENDS FROM THE
BAHAMAS TO THE CENTRAL CARIBBEAN SEA. THIS SYNOPTIC PATTERN IS
GENERATING DIFFLUENT FLOW ALOFT TO SUPPORT SHOWERS AND TSTMS
OVER THE YUCATAN CHANNEL AND SE GULF FROM 24N-25N BETWEEN 81W-
85W...INCLUDING KEY WEST. LOW TO MIDDLE LEVEL DRY AIR SUPPORTS
FAIR WEATHER ELSEWHERE IN THE BASIN. MOSTLY EASTERLY FLOW OF 15-
20 KT DOMINATES THE BASIN. EVEN THOUGH INGRID
DISSIPATED...CONVECTION FROM ITS REMNANTS ARE EXPECTED TO
PREVAIL FOR THE REST OF THE DAY TODAY AND POSSIBLY TOMORROW
MORNING. A BROAD AREA OF LOW PRESSURE OVER THE FAR NW CARIBBEAN
SEA IS STARTING TO MOVE ACROSS THE YUCATAN PENINSULA. THE
DISTURBANCE IS EXPECTED TO MOVE TO THE BAY OF CAMPECHE LATER
TODAY BRINGING SHOWERS AND THUNDERSTORMS. THIS AREA OF LOW
PRESSURE IS EXPECTED TO STALL IN THE BAY OF CAMPECHE FOR SEVERAL
DAYS.

THE CARIBBEAN SEA...
A CUT-OFF LOW EXTENDS A TROUGH ACROSS HISPANIOLA TO THE CENTRAL
CARIBBEAN N OF 15N ENHANCING ISOLATED SHOWERS/TSTMS N OF 12N
BETWEEN 64W-68W.  SCATTERED SHOWERS AND TSTMS ASSOCIATED WITH
THE MONSOON TROUGH ARE OVER THE SOUTHERN BASIN S OF 12N.

HISPANIOLA...
A CUT-OFF LOW EXTENDS A TROUGH ACROSS HISPANIOLA TO THE CENTRAL
CARIBBEAN N OF 15N ENHANCING ISOLATED SHOWERS/TSTMS IN THE
ISLAND ADJACENT WATERS. CONVECTION OVER THE ISLAND AT THIS TIME
CONTINUES TO BE HINDERED BY DRY STABLE AIR AT THE LOWER LEVELS.
EXPECT AFTERNOON AND EVENING SHOWERS TOMORROW ASSOCIATED WITH
SURFACE DAYTIME HEATING.

THE ATLANTIC OCEAN...
THE MAIN FEATURE IN THE ATLC IS TROPICAL STORM HUMBERTO WHICH
INFORMATION IS PROVIDED IN THE SPECIAL FEATURES SECTION. THE
BASE OF AN UPPER-LEVEL TROUGH IS OVER THE SE GULF JUST W OF A
WEAK RIDGE THAT EXTENDS FROM THE BAHAMAS TO THE CENTRAL
CARIBBEAN SEA. THIS SYNOPTIC PATTERN IS GENERATING DIFFLUENT
FLOW ALOFT TO SUPPORT SHOWERS AND TSTMS OVER THE BAHAMAS AND
ADJACENT WATERS FROM 23N-29N BETWEEN 71W-78W. A SURFACE TROUGH
IS OVER THE SW N ATLC FROM 28N66W TO 24N70W GENERATING SCATTERED
SHOWERS FROM 26N-29N BETWEEN 65W-70W.

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

$$
NR


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