[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172354
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE DEC 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN
COAST NEAR 08N13W TO 04N30W TO 0N49W. SCATTERED MODERATE
CONVECTION IS WITHIN 200 NM EITHER SIDE OF THE AXIS E OF 24W AND
WITHIN 170 NM BETWEEN 24W-39W.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY DEPICT A BROAD MIDDLE TO UPPER LEVEL TROUGH
OVER THE EASTERN CONUS WITH A BASE EXTENDING TO THE SW GULF AND
IS PROVIDING MOSTLY DRY AIR AND STABLE CONDITIONS ALOFT TO MUCH
OF THE BASIN. AT THE SURFACE...RIDGING FURTHER SUPPORTS THE
STABILITY ALOFT ANCHORED BY A 1025 MB HIGH ON THE NW GULF NEAR
28N94W. THE RIDGE PROVIDES NORTHEASTERLY WINDS UP TO 15 KT WHICH
ARE EXPECTED TO PREVAIL THROUGH WEDNESDAY AFTERNOON. AS THE HIGH
PRESSURE AREA IS REINFORCED AND BEGINS TO SHIFT EASTWARD LATE
WEDNESDAY INTO EARLY THURSDAY...E-SE FLOW WILL ESTABLISH ACROSS
THE BASIN. AN AREA OF LOW PRESSURE IS FORECAST ACROSS THE
WESTERN GULF ON FRI AFTERNOON ASSOCIATED WITH THE NEXT COLD
FRONT EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COASTS
EARLY SUNDAY.

CARIBBEAN SEA...
A BROAD MIDDLE TO UPPER LEVEL TROUGH EXTENDING ACROSS THE
EASTERN CONUS TO THE WESTERN N ATLC W OF 60W SUPPORTS A FRONTAL
SYSTEM ANALYZED AS A STATIONARY FRONT FROM CENTRAL CUBA NEAR
21N80W TO 19N85W TO THE COASTLINE OF NORTHERN HONDURAS NEAR
16N86W. LOW-LEVEL MOISTURE CONVERGENCE ALONG THE FRONTAL
BOUNDARY AND ALONG THE COASTLINES FROM HONDURAS TO COSTA RICA
SUPPORT SCATTERED SHOWERS AND ISOLATED TSTMS N OF 10N W OF 78W.
IN THE SW BASIN S OF 10N...SCATTERED SHOWERS AND ISOLATED TSTMS
ARE BEING ENHANCED BY THE MONSOON TROUGH THAT EXTENDS ACROSS
SOUTHERN PANAMA TO A 1006 MB LOW NEAR 08N74W. BOTH SSMI TPW AND
WATER VAPOR IMAGERY DEPICT DRY AIR ACROSS THE CENTRAL AND
EASTERN BASIN WHICH CONTINUES TO SUPPORT FAIR WEATHER
CONDITIONS. THE STATIONARY FRONT OVER THE NW BASIN IS EXPECTED
TO DISSIPATE BY WED AFTERNOON.

HISPANIOLA...
CURRENTLY RELATIVELY DRY AIR AND STABLE CONDITIONS AT THE MIDDLE
AND LOWER LEVELS AS DEPICTED IN WATER VAPOR AND SSMI TPW
IMAGERY...RESPECTIVELY. TRADEWINDS ARE EXPECTED TO CONTINUE
ACROSS THE ISLAND WITH WINDS INCREASING SLIGHTLY THURSDAY INTO
FRIDAY DUE TO A STRENGTHENING PRESSURE GRADIENT ACROSS THE
REGION. FAIR WEATHER IS EXPECTED THROUGHOUT EARLY WED...HOWEVER
CONDITIONS MAY DEGRADE IN THE AFTERNOON AS A VERY MOIST AIRMASS
IS EXPECTED TO MOVE ACROSS THE ISLAND.

ATLANTIC OCEAN...
A BROAD MIDDLE TO UPPER LEVEL LONGWAVE TROUGH IS NOTED ON WATER
VAPOR IMAGERY OVER THE EASTERN CONUS THAT SUPPORTS A STATIONARY
FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 30N63W EXTENDING SW
TO THE BAHAMAS NEAR 24N75W THEN ACROSS CENTRAL CUBA AND INTO THE
NW CARIBBEAN SEA. ISOLATED SHOWERS ARE OCCURRING WITHIN 100 NM
EITHER SIDE OF THE FRONT. THE FRONT IS FORECAST TO GRADUALLY
WEAKEN AND BECOME DIFFUSE BY EARLY WEDNESDAY ACROSS THE SW NORTH
ATLC. FARTHER EAST...THE REMAINDER OF THE CENTRAL AND EASTERN
ATLC IS UNDER THE INFLUENCE OF A LARGE AREAL SURFACE RIDGE
ANCHORED BY A 1031 MB HIGH CENTERED NEAR 34N28W.

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

$$
NR

This weather bulletin was brought to you by:
www.nashvilleweather.net