[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUN 21 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
2345 UTC.

...SPECIAL FEATURES...

HURRICANE CHRIS BECAME A TROPICAL STORM AT 21/2100 UTC CENTERED
NEAR 42.4N 42.9W OR ABOUT 585 NM ESE OF CAPE RACE NEWFOUNDLAND
MOVING NNE AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 990
MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT.
SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 120 NM OF
CENTER IN ALL QUADRANTS. SEE LATEST NHC FORECAST/ADVISORY UNDER
AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

AN ELONGATED SURFACE TROUGH EXTENDS FROM THE NE GULF OF MEXICO
ALONG A 1007 MB LOW CENTERED NEAR THE NRN COAST OF THE YUCATAN
PENINSULA NEAR 22N89W INTO INLAND PORTIONS OF THE YUCATAN
PENINSULA AROUND 18N90W. MARINE AND SURFACE OBSERVATIONS
REGISTER A SHARP CYCLONIC TURNING ALONG THE TROUGH AXIS WITH SE
WINDS ON THE ERN SIDE OF THE AXIS GUSTING TO NEAR GALE FORCE
CRITERIA. DOPPLER RADAR AND INFRA-RED SATELLITE IMAGERY
INDICATED SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS
OVER MUCH OF THE CENTRAL AND EASTERN GULF OF MEXICO AND THE
NORTHWESTERN CARIBBEAN SEA...AND ALSO OVER THE YUCATAN
PENINSULA...WESTERN AND CENTRAL CUBA...SOUTHERN FLORIDA...AND
THE NORTHWESTERN BAHAMAS FROM 18N-28N BETWEEN 75W-90W. THIS
SYSTEM IS GRADUALLY BECOMING BETTER DEFINED AND SURFACE
PRESSURES ARE SLOWLY FALLING ACROSS THE AREA. UPPER-LEVEL WINDS
ARE ALSO IMPROVING AND ARE FORECAST TO BECOME MORE CONDUCIVE FOR
DEVELOPMENT OF A TROPICAL DEPRESSION DURING THE NEXT DAY OR SO.
THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS AS IT MOVES SLOWLY NORTHWARD INTO THE
CENTRAL GULF OF MEXICO. INTERESTS ALONG THE ENTIRE UNITED STATES
GULF COAST SHOULD MONITOR THE PROGRESS OF THIS LARGE DISTURBANCE
THROUGH THE WEEKEND. HEAVY RAINS AND LOCALIZED FLOODING ARE
POSSIBLE ACROSS THE YUCATAN PENINSULA...WESTERN CUBA...AND
SOUTHERN FLORIDA THROUGH SATURDAY. AN AIR FORCE RESERVE
RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM
TOMORROW AFTERNOON...IF NECESSARY.

...TROPICAL WAVES...

TROPICAL WAVE EXTENDS FROM NEAR THE CAPE VERDE ISLANDS NEAR
15N25W TO 7N30W MOVING W AT 5-10 KT. THE WAVE PRECEDES A SURGE
OF DEEP MOISTURE ON TOTAL PRECIPITABLE WATER IMAGERY.
HOWEVER...NO SIGNIFICANT CONVECTION IS ASSOCIATED WITH THE WAVE
AT THIS TIME...DUE TO SAHARAN DUST COVERING MUCH OF THE TROPICAL
NORTH ATLC WATERS.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WESTERN AFRICAN COAST OF
GUINEA-BISSAU NEAR 12N16W ALONG 8N22W TO 7N29W. THE ITCZ BEGINS
W OF A TROPICAL WAVE NEAR 6N32W ALONG 7N43W TO 5N55W. CLUSTERS
OF SCATTERED MODERATE CONVECTION ARE WITHIN 160 NM ON EITHER
SIDE OF THE MONSOON TROUGH BETWEEN 17W-29W. SCATTERED WEAK
SHOWERS ARE WITHIN 150 NM N OF THE ITCZ.

...DISCUSSION...

GULF OF MEXICO...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW SPINNING OVER SRN
TEXAS PROVIDING MIDDLE TO UPPER LEVEL LIFTING TO THE WESTERN
GULF AS WELL AS TROPICAL MOISTURE FROM THE ERN TROPICAL PACIFIC
REGION...GENERATING SCATTERED SHOWERS AND THUNDERSTORMS N OF 21N
W OF 92W. THE SECOND REGION OF ACTIVE WEATHER OVER THE GULF IS
ASSOCIATED TO A BROAD/ELONGATED LOW PRESSURE SYSTEM DISCUSSED IN
THE SPECIAL FEATURES SECTION ABOVE. COMPUTER MODELS SUGGEST THIS
SYSTEM WILL CONTINUE TO GENERATE STRONG CONVECTION OVER A GREAT
PORTION OF THE ERN GULF DURING THE NEXT 24 HOURS...WITH THE
POTENTIAL OF FURTHER DEVELOPMENT DURING THE FORECAST PERIOD.

CARIBBEAN SEA...
SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS REMAIN
OVER THE NW CARIBBEAN WATERS N OF 18N W OF 79W...ASSOCIATED TO
THE BROAD SURFACE CYCLONIC WIND FIELD FROM THE SPECIAL FEATURE
LOW PRESSURE SYSTEM CENTERED NEAR THE NRN COAST OF THE YUCATAN
PENINSULA. PERSISTENT CONVECTION IS FORECAST TO CONTINUE ACROSS
THE NW CARIBBEAN DURING THE NEXT FEW DAYS. LOCALLY HEAVY
RAINFALL WITH THE HIGH POTENTIAL FOR FLOODING AND MUDSLIDES IS
LIKELY OVER PORTIONS OF CUBA AND THE YUCATAN PENINSULA DURING
THE FORECAST PERIOD. OTHERWISE...FAIR WEATHER CONDITIONS ARE
ACROSS THE REMAINDER OF THE CARIBBEAN THIS EVENING...WITH 10-20
KT EASTERLY TRADES OBSERVED E OF 80W. JUST A PORTION OF THE
MONSOON TROUGH EXTENDS ACROSS THE FAR SW CARIBBEAN FROM NRN
COLOMBIA TO WRN PANAMA. HOWEVER...THE CONVECTION REMAINS OUT OF
THE DISCUSSION AREA OVER THE ERN TROPICAL PACIFIC WATERS. AN
AREA OF ENHANCED SUSPENDED SAHARAN DUST IS ACROSS THE EASTERN
CARIBBEAN SEA. IMPACTS WILL CONTINUE TO BE HAZY SKY CONDITIONS
OVER THE NEXT FEW DAYS.

ATLANTIC OCEAN...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW SPINNING NEAR
28N70W SUPPORTING A SURFACE TROUGH ANALYZED FROM 31N67W TO
24N73W. WHILE SCATTERED WEAK SHOWERS ARE IN THE VICINITY OF THE
SURFACE TROUGH...MOST OF THE HEAVIEST CONVECTION ASSOCIATED TO
THIS SYSTEM IS WELL OUTSIDE THE LOCATION OF THE SURFACE FEATURE
...DUE TO STRONG DIFFLUENCE ALOFT TO THE S AND SE...GENERATING A
BROAD AREA OF SCATTERED MODERATE TO HEAVY SHOWERS AND
THUNDERSTORMS FROM 21N-27N BETWEEN 62W-70W...AS WELL AS FROM
21N-25N BETWEEN 70W-80W. HEAVY RAINS AND LOCALIZED FLOODING ARE
POSSIBLE ACROSS THE CENTRAL AND NW BAHAMAS THROUGH SATURDAY.
OTHERWISE THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER
THE INFLUENCE OF A SURFACE RIDGE AXIS EXTENDING ACROSS THE
DISCUSSION AREA ANCHORED BY A 1021 MB HIGH NEAR 31N27W AND A
1026 MB HIGH AROUND 39N17W. THE FAIR WEATHER OVER THIS REGION IS
ALSO ASSOCIATED TO SAHARAN DUST DEPICTED ON THE METEOSAT-9
SAHARAN AIR LAYER TRACKING PRODUCT.

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

$$

GARCIA




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