[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN SEP 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURES...
TROPICAL DEPRESSION IDA IS CENTERED NEAR 24.5N 48.7W AT 27/2100
UTC OR ABOUT 885 NM ENE OF THE NORTHERN LEEWARD ISLANDS MOVING W
AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM
SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. ISOLATED
MODERATE CONVECTION IS FROM 24N-29N BETWEEN 45W-50W. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25
KNHC FOR MORE DETAILS.

A 1007 MB SURFACE LOW IS CENTERED NORTH OF THE YUCATAN PENINSULA
COAST NEAR 22N88W THAT LIES BENEATH SOUTHWESTERLY FLOW AND A
DIFFLUENT ENVIRONMENT ALOFT. WHILE SCATTERED MODERATE CONVECTION
IS OCCURRING GENERALLY TO THE EAST AND NORTHEAST OF THE EXPOSED
LOW-LEVEL CIRCULATION CENTER...UPPER LEVEL WIND SHEAR REMAINS A
HINDRANCE TO ANY SIGNIFICANT CENTRALLY ORGANIZED CONVECTION IN
CLOSE PROXIMITY TO THE SURFACE LOW. ASIDE FROM THE MEDIUM
POTENTIAL TO BECOME A TROPICAL CYCLONE IN THE NEXT 48 HOURS...
THE PRIMARY IMPACT FROM THIS SYSTEM WILL CONTINUE TO BE HEAVY
RAINFALL ACROSS THE EASTERN GULF OF MEXICO AND FLORIDA PENINSULA
THROUGH LATE MONDAY.

MID-LEVEL ENERGY IS NOTED ON WATER VAPOR IMAGERY IN THE VICINITY
OF 26N68W THAT SUPPORTS A 1009 MB SURFACE LOW CENTERED NEAR
27N69W. A SURFACE TROUGH AXIS EXTENDS S-SW TO 24N70W TO 22N74W
WITH SCATTERED MODERATE CONVECTION OCCURRING GENERALLY WITHIN
THE SOUTHEASTERN SEMICIRCLE OF THE LOW FROM 24N-28N BETWEEN 66W-
70W. ISOLATED MODERATE CONVECTION IS ELSEWHERE FROM 22N-28N
BETWEEN 62W-70W. THE SYSTEM HOLDS A MEDIUM CHANCE FOR TROPICAL
CYCLONE DEVELOPMENT DURING THE NEXT 48 HOURS AS IT MOVES
NORTHWARD AT 5-10 KT.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 10N35W TO 16N39W MOVING W AT 5 KT.
THE WAVE COINCIDES WITH SUBTLE 700 MB TROUGHING ALOFT BETWEEN
35W-42W AS WELL AS A LOW-LEVEL MONSOONAL GYRE FOCUSED ON A 1009
MB LOW CENTERED AT THE SOUTHERN EXTENT OF THE WAVE AXIS NEAR
10N35W. SCATTERED MODERATE CONVECTION IS FROM 09N-12N BETWEEN
35W-40W...WITH ISOLATED MODERATE CONVECTION ELSEWHERE FROM 04N-
14N BETWEEN 27W-40W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO
12N31W TO A 1009 MB LOW NEAR 10N35W TO 07N43W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM 07N43W TO 02N51W. SCATTERED
MODERATE AND ISOLATED STRONG CONVECTION IS FROM 08N-16N BETWEEN
11W-18W. ISOLATED MODERATE CONVECTION IS FROM 04N-14N BETWEEN
27W-40W.

...DISCUSSION...

GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY
CENTERED OVER COASTAL TEXAS THIS EVENING NEAR 30N95W PROVIDING
MUCH OF THE GULF WITH SOUTHWESTERLY DIFFLUENT FLOW ALOFT. THE
ENERGY ALOFT SUPPORTS A 1008 MB SURFACE LOW CENTERED NEAR 28N94W
GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS N OF 27N
BETWEEN 87W-95W. OVER THE EASTERN GULF...THE UPPER LEVEL
DIFFLUENCE IS MAXIMIZED DUE TO A SHARP RIDGE AXIS ALONG 80W. THE
DIFFLUENCE ALONG WITH A 1007 MB SURFACE LOW CENTERED OFF THE
COAST OF THE NORTHERN YUCATAN PENINSULA NEAR 22N88W CONTINUES TO
GENERATE SCATTERED TO NUMEROUS SHOWERS AND SCATTERED TSTMS
ACROSS THE EASTERN GULF WATERS AND MUCH OF THE FLORIDA PENINSULA
THIS EVENING. THIS LOW IS EXPECTED TO DRIFT NORTHWARD DURING THE
NEXT 24-36 HOURS WITH PLENTY OF CONVECTIVE PRECIPITATION
OCCURRING AS A RESULT ACROSS THE FAR EASTERN GULF WATERS AND
FLORIDA PENINSULA THROUGH LATE MONDAY INTO EARLY TUESDAY.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE AXIS EXTENDS FROM OVER GUATEMALA NEAR
17N89W TO OVER CENTRAL CUBA AND BEYOND TO THE NORTH OVER THE SW
NORTH ATLC WATERS. MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED
OVER THE NW CARIBBEAN AND PORTIONS OF CUBA GENERATING SCATTERED
SHOWERS AND ISOLATED TSTMS OCCURRING GENERALLY W OF 79W THIS
EVENING. FARTHER SOUTH...ISOLATED SHOWERS AND TSTMS ARE
OCCURRING ACROSS PORTIONS OF COSTA RICA AND PANAMA DUE TO THE
CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 10N/11N.
CONDITIONS ACROSS THE EASTERN CARIBBEAN REMAIN FAIRLY QUIET AND
TRANQUIL THIS EVENING WITH ONLY ISOLATED SHOWERS OCCURRING
ACROSS HISPANIOLA AND A WEAK SURFACE TROUGH ANALYZED FROM 16N62W
SE TO 13N54W IN ASSOCIATION WITH A BROAD UPPER LEVEL LOW
CENTERED NEAR 16N60W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 75 NM
EITHER SIDE OF THE BOUNDARY. OTHERWISE...MAINLY FRESH TO
OCCASIONAL STRONG TRADES PERSIST WITH THE STRONGEST WINDS NOTED
ACROSS SOUTH-CENTRAL PORTIONS. BY MID-WEEK...THE TRADES ARE
EXPECTED TO RELAX SOMEWHAT INTO MODERATE TO FRESH BREEZE LEVELS
AS BROAD FRONTAL TROUGHING IS EXPECTED TO OCCUPY MUCH OF THE SW
NORTH ATLC REGION TO THE NORTH.

...HISPANIOLA...
CURRENTLY LINGERING LATE AFTERNOON AND EARLY EVENING ISOLATED
SHOWERS CONTINUE TO GRADUALLY DIMINISH WITH MOSTLY FAIR SKIES
EXPECTED FOR THE OVERNIGHT HOURS INTO EARLY MONDAY. NORTHERLY
FLOW ALOFT PREVAILS OVER THE ISLAND PROVIDING MOSTLY STABLE
CONDITIONS AT THIS TIME.

ATLANTIC OCEAN...
ASIDE FROM THE SPECIAL FEATURES LOW CENTERED NEAR 27N69W...THE
REMAINDER OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A
RELATIVELY DIFFLUENT ENVIRONMENT ALOFT WITH ISOLATED SHOWERS
AND TSTMS OCCURRING GENERALLY W OF 78W THIS EVENING. FARTHER EAST
ACROSS THE CENTRAL ATLC IS TROPICAL DEPRESSION IDA...WITH A COLD
FRONT ANALYZED TO THE NORTH FROM 32N40W TO 29N51 THAT BECOMES
STATIONARY TO 30N61W TO BEYOND 32N65W TO THE COAST OF THE
CAROLINAS. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 180
NM EAST OF THE COLD FRONT AND WITHIN 120 NM EITHER SIDE OF THE
STATIONARY FRONT W OF 55W. OTHERWISE...THE EASTERN ATLC IS UNDER
THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1018 MB HIGH
CENTERED NEAR 30N29W.

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

$$
HUFFMAN
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