Tropical Weather Discussion
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000
AXNT20 KNHC 291804
TWDAT

TROPICAL WEATHER DISCUSSION...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 29 2014


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
1745 UTC.


...TROPICAL WAVES...

A TRPCL WAVE CAME OFF THE WEST AFRICAN COAST THIS MORNING. ITS
AXIS EXTENDS FROM 12N17W TO 2N17W AND IS EXPECTED TO MOVE W AT A
SPEED OF 15 KT DURING THE NEXT 24 HOURS. THE GOES-R AIRMASS
PRODUCT SHOW MIDDLE TO UPPER LEVEL DRY AIR MAINLY IN THE N-NW
WAVE ENVIRONMENT WHERE SOME DUST IS ALSO OBSERVED. MIDDLE-LEVEL
CLOUDS ARE IN THE CENTRAL WAVE ENVIRONMENT WHILE HIGH CLOUDS ARE
SW OF THE AXIS WHERE SCATTERED SHOWERS AND ISOLATED TSTMS ARE S
OF 6N WITHIN 160 NM.

A TROPICAL WAVE IS IN THE CENTRAL ATLANTIC WITH AXIS EXTENDING
FROM 18N37W TO 9N42W...MOVING W AT 20 KT. THE GOES-R AIRMASS
PRODUCT SHOW MIDDLE TO UPPER LEVEL DRY AIR IN THE CENTRAL AND
SOUTHERN ENVIRONMENT...WHICH IS HINDERING CONVECTION IN THIS
REGION OF THE WAVE. DEEP LAYER MOISTURE IS IN THE NORTHERN
REGION OF THE WAVE WHERE SCATTERED MODERATE CONVECTION AND
ISOLATED TSTMS ARE FROM 14N-18N BETWEEN 37W-41W.

A TROPICAL WAVE IS IN THE WESTERN CARIBBEAN WITH AXIS EXTENDING
FROM 22N81W TO 10N81W...MOVING WESTWARD AT 15 KT. A MIDDLE LEVEL
INVERTED TROUGH CONTINUE TO SUPPORT THIS WAVE ASSOCIATED WITH
LOW TO MIDDLE MODERATE MOISTURE. ISOLATED MODERATE CONVECTION
AND TSTMS ARE WITHIN 180 NM E OF WAVE AXIS S OF 19N.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N13W TO
6N17W TO 5N22W. THE ITCZ EXTENDS FROM 5N23W TO 4N30W TO 6N39W.
SCATTERED MODERATE CONVECTION IS FROM 2N-6N BETWEEN 15W-28W.

...DISCUSSION...

GULF OF MEXICO...

A MIDDLE-LEVEL TROUGH SUPPORTS A STATIONARY FRONT EXTENDING
ACROSS NORTHERN FLORIDA AND THE NORTHERN GULF ALONG 30N83W TO A
1011 MB LOW NEAR 29N86W TO 27N92W 27N96W TO 22N97W. A PRE-
FRONTAL TROUGH EXTENDS FROM 26N91W TO 24N95W TO 20N96W
SUPPORTING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS IN
THE BAY OF CAMPECHE S OF 21N W OF 94W. IN THE UPPER-LEVELS A
RIDGE IS ANCHORED OVER THE NW GULF WHILE THE REMAINDER BASIN AND
THE FLORIDA PENINSULA ARE UNDER THE INFLUENCE OF ANOTHER RIDGE
ANCHORED NEAR 23N83W. THIS RIDGES ARRANGEMENT IN THE UPPER
LEVELS IS GENERATING A DIFFLUENT ENVIRONMENT THAT ALONG DEEP
LAYER MOISTURE SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS N
OF 25N E OF 89W. THE PORTION OF THE FRONT IN THE NE GULF IS
FORECAST TO TRANSITION INTO A COLD FRONT TONIGHT THAT WILL MOVE
ACROSS CENTRAL FLORIDA TUE MORNING.

CARIBBEAN SEA...

THE HIGHLIGHT IN THE BASIN IS A TROPICAL WAVE MOVING ACROSS THE
WESTERN BASIN DISCUSSED IN THE WAVES SECTION ABOVE. DRY AIR
SUBSIDENCE IS SUPPORTING FAIR WEATHER WEST OF THE WAVE AXIS
WHILE BOTH DRY AIR AND STRONG DEEP LAYER ENVIRONMENTAL SHEAR
SUPPORT FAIR WEATHER ACROSS THE CENTRAL AND EASTERN BASIN. A
SLIGHT TIGHTENING OF THE PRESSURE GRADIENT DUE TO THE PASSAGE OF
THE TROPICAL WAVE SUPPORT TRADES OF 15-20 KT ACROSS THE CENTRAL
BASIN WHILE WINDS OF 10 KT DOMINATE ELSEWHERE. THE TROPICAL WAVE
IS FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA BY TUE MORNING.

...HISPANIOLA...

AN ELONGATED UPPER LEVEL TROUGH OVER PORTIONS OF THE SW N ATLC
EXTENDS SW ACROSS THE ISLAND AND THE CENTRAL-EASTERN
CARIBBEAN...WHICH ALONG SHALLOW MOISTURE SUPPORT CLOUDINESS
ACROSS MOST OF THE ISLAND. THE UPPER TROUGH IS FORECAST TO SHIFT
E GIVING THE ISLAND MORE NORTHERLY FLOW ALOFT. THIS WILL LIMIT
HEAVY RAIN...BUT AFTERNOON SHOWERS COULD STILL DEVELOP DUE TO
DAYTIME HEATING THROUGH WED.

ATLANTIC OCEAN...

A STATIONARY FRONT EXTENDS ACROSS NORTHERN FLORIDA BEING
SUPPORTED BY A MIDDLE-LEVEL TROUGH...WHICH IS ENHANCING
SCATTERED SHOWERS N OF 28N W OF 74W. A 1008 MB LOW PRESSURE
CENTER IS LOCATED NEAR 32N65W JUST WEST OF BERMUDA BEING
SUPPORTED BY A MIDDLE TO UPPER LEVEL LOW EXTENDING A TROUGH AXIS
INTO A PORTION OF THE SW N ATLC WATERS. RAINBANDS OF MODERATE
CONVECTION AND TSTMS ARE FROM 30N-35N WITHIN 300 NM E OF THE LOW
CENTER. SIMILAR CONVECTION EXTENDS S OF 30 N BETWEEN 59W-70W.
HEAVY SHOWERS AND GUSTY WINDS ARE EXPECTED FOR BERMUDA THROUGH
TONIGHT. THE REMNANTS OF THREE LOW PRESSURE CENTERS ARE BEING
ANALYZED AS THREE SURFACE TROUGHS...ONE ALONG 27N44W TO
23N51W...A SECOND ALONG 27N34W TO 20N41W AND THE THIRD AHEAD OF
A TROPICAL WAVE FROM 18N45W TO 15N48W. SURFACE RIDGING DOMINATES
ELSEWHERE ACROSS THE BASIN N OF 19N.

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

$$
NR


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