[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUL 17 2012

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.

...TROPICAL WAVES...

TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS ALONG 21N22W
TO 15N21W MOVING W AT 5-10 KT. A LARGE AREA OF DUST SURROUNDING
THE WAVE HAS DAMPENED MOST OF THE MOISTURE SIGNAL NEAR THE AXIS
AS SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. THERE IS A MOISTURE
SURGE WELL W OF THE WAVE...BUT MODEL GUIDANCE AGREES WITH THE
CURRENT POSITION AND NOT A POSITION FARTHER W. THE DUST IS
CURRENTLY LIMITING CONVECTION NEAR THE WAVE AXIS.

TROPICAL WAVE IS ALONG 19N50W TO 11N49W MOVING W AT 15 KT. THE
WAVE LIES ON THE W SIDE OF A SURFACE OF DEEP LAYER MOISTURE
PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. A SMALL AREA OF
MODERATE CONVECTION IS FROM 13N-14N BETWEEN 49W-50W.

TROPICAL WAVE MOVES ACROSS CENTRAL CUBA ALONG 24N80W TO 16N80W
MOVING W NEAR 10 KT. THE WAVE IS EMBEDDED WITHIN AN AREA OF
ENHANCED MOISTURE PRESENT ACROSS MUCH OF THE WRN CARIBBEAN. AN
UPPER LEVEL LOW CENTERED OVER THE YUCATAN PENINSULA IS HELPING
FLARE UP CONVECTION OVER THE WRN CARIBBEAN AND NEAR THE WAVE. IT
IS HARD TO SAY WHETHER IT IS RELATED MOST TO THE WAVE OR DAYTIME
HEATING AND UPPER LEVEL DIFFLUENCE. REGARDLESS...A CLUSTER OF
STRONG CONVECTION IS ACROSS CUBA W OF THE WAVE AXIS FROM 22N-24N
BETWEEN 80W-82W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 16N-19N BETWEEN 80W-86W. THE REMAINDER OF THE CONVECTION
IN THE W ATLC IS FARTHER REMOVED FROM THE WAVE AND WILL BE
DISCUSSED IN THE CARIBBEAN SECTION.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
SENEGAL AT 14N17W CONTINUING S OF THE TROPICAL WAVE TO NEAR
12N27W 9N38W 10N48W. THE ITCZ BEGINS AT 10N48W CONTINUING TO
7N58W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF THE
MONSOON TROUGH FROM 10N-13N BETWEEN 19W-24W. SCATTERED MODERATE
CONVECTION IS FROM 5N-10N BETWEEN 32W-44W...AND FROM 7N-10N
BETWEEN 48W-53W.

...DISCUSSION...

GULF OF MEXICO...
A PAIR OF UPPER LEVEL LOWS CONTINUE TO IMPACT THE GULF OF MEXICO
TONIGHT SUPPORTING LARGE AREAS OF SHOWERS/THUNDERSTORMS. THE
FIRST UPPER LOW IS CENTERED OVER SE GEORGIA NEAR 31N82W
SUPPORTING A SURFACE TROUGH FROM 31N83W TO 27N85W. RADAR IMAGERY
INDICATES NUMEROUS SHOWERS/SCATTERED THUNDERSTORMS ARE ACROSS
MUCH OF THE FLORIDA PANHANDLE N OF 29N BETWEEN 82W-88W. ISOLATED
SHOWERS/THUNDERSTORMS COVER THE REMAINDER OF THE STATE AND THE
ERN GULF E OF 88W. SOME OF THE ACTIVITY NEAR S FLORIDA AND THE
SE GULF ARE TIED TO THE SECOND UPPER LEVEL LOW CENTERED OVER THE
NRN YUCATAN PENINSULA NEAR 21N88W. IT IS HELPING SUPPORT STRONG
SHOWERS/THUNDERSTORMS ACROSS THE YUCATAN PENINSULA AND PORTIONS
OF CENTRAL AMERICA. SOME ISOLATED SHOWERS ARE ALSO OVER THE FAR
WRN GULF W OF 95W. THE REMAINING PORTION OF THE CENTRAL GULF IS
EXPERIENCING FAIR WEATHER INFLUENCED BY DRY AIR ALOFT AROUND AN
UPPER LEVEL RIDGE OVER THE MIDWEST CONUS SUPPORTING A SURFACE
1018 MB HIGH OVER SE LOUISIANA. THE UPPER LOWS ARE EXPECTED TO
REMAIN SOMEWHAT STATIONARY AND WILL LIKELY KEEP THE ERN GULF
UNDER MOIST CONDITIONS FOR AT LEAST THE NEXT 24 HOURS.

CARIBBEAN SEA...
THE UPPER LEVEL LOW OVER THE NRN YUCATAN PENINSULA IS SUPPORTING
STRONG SHOWERS/THUNDERSTORMS ACROSS MUCH OF NRN CENTRAL AMERICA
INCLUDING BELIZE...GUATEMALA...HONDURAS...AND NRN NICARAGUA. A
STRONG CLUSTER OF SHOWERS/THUNDERSTORMS IS ALSO OVER WRN CUBA
WITH SOME ISOLATED ACTIVITY OVER THE NW CARIBBEAN WATERS
POSSIBLY TIED TO A TROPICAL WAVE ALONG 80W. SEE TROPICAL WAVE
SECTION ABOVE FOR MORE DETAILS. STRONG SHOWERS/THUNDERSTORMS ARE
ALSO ACROSS COSTA RICA AND PANAMA ASSOCIATED WITH THE E PACIFIC
MONSOON TROUGH THAT EXTENDS S OF BOTH COUNTRIES TO A 1008 MB LOW
OVER NRN COLOMBIA. THE REMAINDER OF THE CARIBBEAN IS
EXPERIENCING FAIR WEATHER DUE TO DRY AIR ALOFT AROUND AN UPPER
LEVEL TROUGH OVER THE ERN CARIBBEAN...AND AN UPPER LEVEL RIDGE
OVER THE S CENTRAL CARIBBEAN. A LARGE AREA OF SAHARAN DUST IS
ALSO PRESENT ACROSS THE CENTRAL AND ERN CARIBBEAN EVIDENT IN
SATELLITE IMAGERY AND SURFACE OBSERVATIONS. TRADEWIND FLOW OF
20-25 KTS IS PRESENT OVER THE CENTRAL CARIBBEAN WITH LIGHTER
WINDS TO EITHER SIDE. EXPECT THE TROPICAL WAVE TO CONTINUE
MOVING WWD FURTHER INTO THE NW CARIBBEAN. MOIST CONDITIONS WILL
BE LIKELY ACROSS THIS AREA.

ATLANTIC OCEAN...
AN UPPER LEVEL LOW CENTERED OVER SE GEORGIA IS SUPPORTING
SCATTERED SHOWERS/THUNDERSTORMS JUST E OF THE FLORIDA COAST
ALONG WITH SOME ISOLATED SHOWERS/THUNDERSTORMS N OF 27N W OF
73W. THE REMAINDER OF THE W ATLC IS DOMINATED BY SURFACE RIDGING
AROUND A 1021 MB HIGH NEAR 27N66W PROVIDING FAIR CONDITIONS. THE
HIGH IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED NEAR 31N67W.
AN UPPER LEVEL TROUGH IS TO THE E ALONG 31N57W TO 18N63W WHERE
IT CONTINUES INTO THE ERN CARIBBEAN. THE UPPER TROUGH SUPPORTS A
WEAK SURFACE TROUGH ALONG 32N52W TO 28N53W WITH ISOLATED SHOWERS
WITHIN 75 NM EITHER SIDE. THE ERN ATLC IS COVERED BY SURFACE
RIDGING ANCHORED BY A PAIR OF 1030 MB AZORES HIGHS...WHICH ARE
PROVIDING FAIR WEATHER ACROSS THE REMAINDER OF THE BASIN. THE
SURFACE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE COVERING THE
ERN TRPCL ATLC. VISIBLE SATELLITE IMAGERY INDICATES A LARGE AREA
OF SAHARAN DUST COVERS MUCH OF THE TROPICAL ATLC AROUND THE
TROPICAL WAVES...WHICH IS HELPING SUPPORT FAIR SURFACE
CONDITIONS.

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

$$
WALTON





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