[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222359
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT JUN 22 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
2345 UTC.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 12N38W TO 2N37W MOVING W NEAR 15 KT.
WAVE IS EMBEDDED WITHIN A LOW AMPLITUDE SURGE OF DEEP MOISTURE
AS DEPICTED BY THE TOTAL PRECIPITABLE WATER IMAGERY AND THE GOES-
R PROVING GROUND RGB AIRMASS IMAGERY. THE SAME IMAGERY SUGGESTED
SOME SAHARAN DUST ATTEMPTING TO WRAP AROUND THE W SIDE OF THE
WAVE ALONG THE ITCZ AND EXTENDING NE OF THE WAVE TO AFRICA.
DESPITE THIS SCATTERED MODERATE WITH EMBEDDED CLUSTERS OF
ISOLATED STRONG CONVECTION WERE NOTED FROM 4N-7N BETWEEN 39W-
43W.

TROPICAL WAVE EXTENDS FROM 12N51W TO 3N51W MOVING W AT 15 KT.
WAVE IS AT THE LEADING EDGE OF SAHARAN DUST AS INDICATED BY THE
GOES-R PROVING GROUND RGB AIRMASS IMAGERY. THE INTRUSION OF THE
SAHARAN AIR WAS LIMITING SHOWER AND THUNDERSTORM ACTIVITY.

TROPICAL WAVE IN THE W CARIBBEAN EXTENDS FROM 20N83W TO COSTA
RICA NEAR 11N83W MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN THE
FAR SW EXTENT OF THE TROPICAL UPPER TROPOSPHERIC TROUGH. WAVE IS
INTERACTING WITH THE MONSOON TROUGH AND SITUATED WITHIN AN AREA
OF UPPER LEVEL DIFFLUENCE TO GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS BETWEEN THE WAVE AXIS AND THE COAST OF NICARAGUA
AND COSTA RICA.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 13N17W AND IMMEDIATELY TRANSITIONS TO THE ITCZ NEAR
10N20W...THEN CONTINUES THROUGH 8N27W...9N35W...6N44W TO 7N51W.
THE ITCZ AGAIN RESUMES NEAR 6N52W AND CONTINUES INLAND OVER
SOUTH AMERICA NEAR 6N58W. NO SIGNIFICANT CONVECTION WAS NOTED
ALONG THE AXIS.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW IS SITUATED OVER EXTREME E TENNESSEE IS PROVIDING
WANING SUPPORT FOR A STATIONARY SURFACE TROUGH EXTENDING FROM
APALACHICOLA FLORIDA TO EXTREME SE LOUISIANA. WEAKENING
SHOWERS/THUNDERSTORMS ARE WITHIN 120 NM S OF THE TROUGH E OF
90W. MOST OF THE OPEN GULF WAS FAIRLY CLOUD FREE WITH
THUNDERSTORM ACTIVITY NOTED OVER COASTAL WATERS OF SW FLORIDA...
SE MEXICO AND THE W COAST OF THE YUCATAN PENINSULA. THE SURFACE
RIDGE WILL PREVAIL ACROSS THE GULF THROUGH WED.

CARIBBEAN SEA...
THE TROPICAL UPPER TROPOSPHERIC TROUGH EXTENDS FROM THE SW N
ATLC THROUGH AN UPPER LOW JUST N OF EXTREME E CUBA THEN TO
ANOTHER UPPER LOW NEAR 18N82W. DIFFLUENT NW FLOW ALOFT TO THE S
OF THE UPPER TROUGH COUPLED WITH LOW LEVEL CONVERGENCE NEAR THE
MONSOON TROUGH WHICH EXTENDS FROM COLOMBIA NEAR 9N76W ALONG 10N
TO COSTA RICA IS GENERATING SCATTERED MODERATE TO STRONG
THUNDERSTORMS WITHIN 60-90 NM OF THE COAST FROM NICARAGUA TO
PANAMA. ADDITIONAL THUNDERSTORM ACTIVITY OVER CUBA W OF 80W WAS
TOPOGRAPHICALLY AND DIURNALLY ENHANCED. BROAD SWATH OF W TO SW
FLOW AT THE UPPER LEVELS COVERED THE CARIBBEAN E OF 72W BETWEEN
THE AFOREMENTIONED TROUGH AND AN UPPER RIDGE ANCHORED IN THE
TROPICAL ATLC ALONG 45W. AT THE SURFACE MODERATE EASTERLY TRADE
WINDS ARE GENERATING SCATTERED LOW LEVEL SHOWERS WITH POSSIBLE
ISOLATED THUNDERSTORMS N OF 13N W OF 71W TO ACROSS THE LESSER
ANTILLES. THE TROPICAL WAVE IN THE W CARIBBEAN WILL MOVE INTO
CENTRAL AMERICA TONIGHT. A WEAK TROPICAL WAVE WILL MOVE INTO E
CARIBBEAN EARLY MON AND REACH THE CENTRAL CARIBBEAN TUE. A THIRD
TROPICAL WAVE WILL MOVE INTO THE E CARIBBEAN WED.

HISPANIOLA...
INCREASING S TO SW UPPER LEVEL FLOW IS SPREADING W ACROSS
HISPANIOLA AS AN UPPER LOW JUST TO THE NE OF EASTERN CUBA MOVES
W. A SLOT OF DRY AIR ALOFT COVERS HAITI WHILE INCREASING UPPER
LEVEL MOISTURE IS BEING ADVECTED ACROSS THE DOMINICAN REPUBLIC.
PRECIPITABLE WATER FIELDS FROM BOTH THE GFS/ECMWF ARE FORECAST
TO INCREASE FROM CURRENT VALUES OF 1.25 INCHES TO NEARLY 2
INCHES BY LATE SUN THEREBY INCREASING THE CHANCES FOR MORE
WIDESPREAD SHOWER/THUNDERSTORM ACTIVITY ON SUN INTO MON.
MOISTURE INCREASES EVEN MORE ON WED AND THU AHEAD OF A STRONG
TROPICAL WAVE THAT WILL ENTER THE E CARIBBEAN WITH WIDESPREAD
SHOWERS AND THUNDERSTORMS THROUGH THE END OF THE WEEK.

ATLANTIC OCEAN...
THE UPPER LOW OVER E TENNESSEE IS SUPPORTING A STATIONARY
SURFACE TROUGH EXTENDING FROM NEAR 32N80W TO NE FLORIDA NEAR
JACKSONVILLE AND CONTINUES INTO THE GULF OF MEXICO. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60/75 NM SE OF THE
FRONT/TROUGH EXTENDING ACROSS THE W COAST OF FLORIDA. A SURFACE
TROUGH EXTENDS FROM 30N77W TO JUST W OF ANDROS ISLAND IN THE
BAHAMAS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS E OF
THE TROUGH TO 76W. THIS SURFACE TROUGH IS BENEATH AN UPPER RIDGE
THAT COVERS THE W ATLC ANCHORED NEAR GRAND BAHAMA ISLAND AND
EXTENDING A RIDGE AXIS N TO BEYOND 32N75W. ANOTHER SURFACE
TROUGH EXTENDS FROM 27N59W TO 21N61W AND IS MOVING W AT 20 KT
ACROSS THE ATLC ABOUT 300 NM N-NE OF THE LEEWARD ISLANDS. THE
REMAINDER OF THE ATLC IS DOMINATED BY A BROAD SURFACE RIDGE
ANCHORED BY A 1034 MB HIGH NEAR THE AZORES. A PLUME OF DENSE
SAHARAN DUST COVERS THE ATLC N OF 10N E OF 35W. THIS DUST THINS
OVER THE AREA FROM 10N-24N BETWEEN 35W-54W. SURFACE RIDGE WILL
CONTINUE TO DOMINATE THE ATLC THROUGH WED.

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

$$
COBB


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