[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 172346
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUN 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
2100 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 17N41W TO 8N42W MOVG W AT 10-15 KT. THE
WAVE LIES ON THE WRN LEADING EDGE OF A SURGE IN DEEP LAYER
MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP
CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE. THIS MAY BE
DUE TO A LARGE AREA OF SAHARAN DUST THAT EXTENDS E OF THE WAVE
TO THE AFRICAN COAST.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF
SENEGAL AT 13N17W TO 9N25W. THE ITCZ CONTINUES AT 9N25W ALONG
7N32W 9N41W 6N53W. CONVECTION ALONG THE AXIS IS LIMITED DUE TO A
LARGE AREA OF SAHARAN DUST EXTENDING FROM THE COAST OF AFRICA TO
THE TROPICAL WAVE. ONLY A SMALL AREA OF MODERATE CONVECTION IS
NOTED ALONG THE AXIS BETWEEN 30W-37W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH CONTINUES TO IMPACT THE NRN GULF OF MEXICO
ALONG 30N91W TO 26N97W PRODUCING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 24N-31N BETWEEN 86W-91W. THE SURFACE TROUGH
IS SUPPORTED BY A SHORTWAVE UPPER TROUGH THAT EXTENDS FROM
LOUISIANA TO THE YUCATAN CHANNEL. UPPER LEVEL RIDGING IS TO
EITHER SIDE OF THE SHORTWAVE TROUGH ACCOMPANIED BY DRY AIR
ALOFT. THIS DRY AIR IS HELPING PROVIDE FAIR CONDITIONS ACROSS
THE FLORIDA PENINSULA AND THE NW GULF. WEAK SURFACE RIDGING ALSO
EXTENDS INTO THE NE GULF FROM A HIGH CENTER OVER NRN GEORGIA.
THE SW GULF IS HIT BY MOISTURE STREAMING AROUND THE E PACIFIC
MONSOON TROUGH...WHICH HAS SHIFTED TO THE N OVER THE PAST COUPLE
OF DAYS. THIS IS CAUSING WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS
CENTRAL AMERICA...SRN MEXICO...AND THE YUCATAN PENINSULA. SOME
OF THE ACTIVITY EXTENDS OVER THE SW GULF S OF 20N. EXPECT MOIST
CONDITIONS TO REMAIN OVER THE SRN GULF FOR THE NEXT SEVERAL DAYS
AS A SURFACE TROUGH CURRENTLY IN THE WRN CARIBBEAN DRIFTS NW
THROUGH THE MIDDLE OF THE WEEK. FLOODING AND MUDSLIDES WILL BE
POSSIBLE IN AREAS ACROSS CENTRAL AMERICA AND MEXICO THAT HAVE
ALREADY RECEIVED LARGE AMOUNTS OF RAIN...ESPECIALLY OVER
MOUNTAINOUS TERRAIN. THE SURFACE TROUGH CURRENTLY IN THE N
CENTRAL GULF WILL CONTINUE TO MOVE WNW INTO TEXAS WITH SHOWERS
LIKELY IN CLOSE PROXIMITY TO THE AXIS.

CARIBBEAN SEA...
BROAD CYCLONIC SURFACE FLOW ALONG WITH A LARGE AREA OF
SHOWERS/THUNDERSTORMS COVER PORTIONS OF THE CENTRAL AND WRN
CARIBBEAN. CURRENTLY A LARGE CLUSTER OF STRONG
SHOWERS/THUNDERSTORMS IS APPROACHING HISPANIOLA FROM 14N-18N
BETWEEN 67W-72W. A CLUSTER OF SIMILAR ACTIVITY IS NOW MOVING N
OF PUERTO RICO LEAVING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ACROSS THE ISLAND. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITH
SOME CLUSTERS OF STRONG SHOWERS COVER THE AREA FROM 13N-20N
BETWEEN 72W-89W INCLUDING MUCH OF CENTRAL AMERICA. CLUSTERS OF
SHOWERS/THUNDERSTORMS ARE ALSO ACROSS CUBA. SOME OF THIS
ACTIVITY IS ATTRIBUTED TO A BROAD SURFACE TROUGH ALONG 19N80W TO
A 1008 MB LOW NEAR 14N82W...AS OF 2100 UTC. TROUGHING ALSO
EXTENDS TOWARDS THE NE INTO THE W ATLC. ACTIVITY ACROSS CENTRAL
AMERICA IS ALSO ENHANCED BY A PORTION OF THE E PACIFIC MONSOON
TROUGH THAT EXTENDS FROM SRN MEXICO THROUGH MOST OF CENTRAL
AMERICA. THE FAR ERN CARIBBEAN IS THE ONLY PORTION OF THE BASIN
THAT IS UNDER MOSTLY FAIR CONDITIONS WITH REPORTS OF DUST.
ALOFT...MAINLY ZONAL WLY FLOW COVERS THE BASIN WRAPPING AROUND A
HORIZONTALLY ALIGNED UPPER RIDGE THAT EXTENDS FROM CENTRAL
MEXICO ACROSS NRN CENTRAL AMERICA TO THE NE CARIBBEAN WHERE IT
CONTINUES INTO THE ATLC. EXPECT THE BROAD AREA OF SURFACE
TROUGHING TO MOVE SLOWLY TOWARDS THE NW. THIS MEANS THAT MOIST
CONDITIONS WILL REMAIN ACROSS MUCH OF THE CENTRAL AND WRN
CARIBBEAN. FLOODING AND MUDSLIDES ARE POSSIBLE IN AREAS THAT
HAVE ALREADY RECEIVED LARGE AMOUNTS OF RAIN...ESPECIALLY ACROSS
MOUNTAINOUS TERRAIN.

ATLANTIC OCEAN...
A LARGE UPPER LEVEL LOW CENTERED NEAR 33N68W IS IMPACTING THE
WRN ATLC. THE UPPER LOW SUPPORTS A 1005 MB SURFACE LOW NEAR
32N64W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO THE
WINDWARD PASSAGE IN THE CARIBBEAN. SHOWERS/THUNDERSTORMS EXTEND
UP TO 525 NM E OF THE AXIS WITH ONLY A SMALL AREA OF
SHOWERS/THUNDERSTORMS W OF THE AXIS FROM 25N-28N. A SURFACE
RIDGE IS BUILDING IN BEHIND THE TROUGH PROVIDING FAIR CONDITIONS
W OF THE TROUGH AXIS. ACROSS THE CENTRAL ATLC...A SHORTWAVE UPPER
RIDGE...TROUGH...RIDGE PATTERN IS PRESENT WITH AN UPPER RIDGE
AXIS ALONG 56W AND 46W WITH AN UPPER TROUGH BETWEEN THE TWO.
ACROSS THE ERN ATLC...AN UPPER LEVEL RIDGE IS CENTERED NEAR
30N376W SUPPORTING A 1026 MB SURFACE HIGH NEAR 31N29W...WHICH IS
PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER OF THE BASIN. AN
UPPER LEVEL LOW IS S OF THE UPPER RIDGE CENTERED NEAR
18N38W...BUT IS NOT CAUSING ANY SIGNIFICANT WEATHER. AN UPPER
LEVEL RIDGE COVERS THE FAR ERN ATLC CENTERED OVER W AFRICA NEAR
20N15W. THE LAST VISIBLE SATELLITE IMAGERY OF THE DAY ALONG WITH
GOES-R IMAGERY ENHANCEMENTS INDICATE THAT A LARGE AREA OF
SAHARAN DUST EXTENDS FROM THE COAST OF AFRICA TO NEAR
45W...CLEARING SOMEWHAT AROUND THE TROPICAL WAVE.

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

$$
WALTON





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