Tropical Weather Discussion
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000
AXNT20 KNHC 260001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUN 25 2015

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...

MINIMAL GALE-FORCE WINDS ARE EXPECTED TO RAMP AGAIN SHORTLY IN
THE COASTAL AND OFFSHORE WATERS OF COLOMBIA...FROM 11.5N TO 16N
BETWEEN 70W AND 80W...THE WINDS ARE FORECAST TO PULSE AROUND
MARGINAL GALE-FORCE FOR THE NEXT 48 HOURS. WAVE HEIGHTS ARE
FORECAST TO RANGE FROM 11 FEET TO 17 FEET DURING THE NEXT 48
HOURS. PLEASE READ THE HIGH SEAS FORECAST... MIAHSFAT2/FZNT02
KNHC...AND THE OFFSHORE FORECAST...MIAOFFNT3/ FZNT23 KNHC...FOR
MORE DETAILS.

...TROPICAL WAVES...

LOW AMPLITUDE TROPICAL WAVE IS ALONG 38W/39W FROM 13N
SOUTHWARD...MOVING WESTWARD 20 KNOTS. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION WAS NOTED AT THE INTERSECTION OF
THE WAVE AXIS AND THE ITCZ FROM 5N TO 8N BETWEEN 36W AND 42W.

TROPICAL WAVE IS ALONG 55W FROM 20N SOUTHWARD...MOVING WESTWARD
AT 20 KNOTS. LAST VISIBLE SATELLITE IMAGES DEPICTED AN INVERTED-
V SHAPE IN THE LOW LEVEL CLOUDINESS ACCOMPANYING THE WAVE.
SCATTERED LOW TOPPED SHOWERS ARE POSSIBLE IN THE ASSOCIATED
CLOUDINESS.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 80W/81W FROM 17N
SOUTHWARD. THE WAVE IS MOVING WESTWARD 10 TO 15 KNOTS. NO
SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE WAVE.

A TROPICAL WAVE IS MOVING THROUGH THE FAR SOUTHWESTERN CORNER OF
THE GULF OF MEXICO. IT IS MOVING BENEATH THE AREA OF THE MID TO
UPPER LEVEL CYCLONIC FLOW THAT IS ACCOMPANYING THE
CYCLONIC CIRCULATION NEAR 23N94W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF SENEGAL
NEAR 13N17W TO 10N22W. THE ITCZ CONTINUES FROM 10N22W THROUGH
9N32W 5N43W TO 6N53W NEAR THE COAST OF FRENCH GUIANA. NO
SIGNIFICANT CONVECTION WAS NOTED OUTSIDE THE AREA NOTED IN
ASSOCIATION WITH THE TROPICAL WAVE ALONG 38W/39W ABOVE.

...DISCUSSION...

...GULF OF MEXICO...

LARGE-SCALE MID-TO UPPER LEVEL CYCLONIC FLOW COVERS THE GULF OF
MEXICO S OF 28N W OF 85W ANCHORED BY A CYCLONIC CIRCULATION NEAR
23N94W. ANTICYCLONIC FLOW PREVAILED OVER THE NORTHEAST GULF S OF
A NARROW RIDGE AXIS ALONG THE IMMEDIATE GULF COAST. AT THE
SURFACE A 1021 MB HIGH CENTER WAS NEAR 28N86W. A TROUGH EXTENDED
FROM NEAR PENSACOLA FLORIDA TO 28N90W TO THE COAST OF LOUISIANA
NEAR LAKE CHARLES. SURFACE OBSERVATIONS AND SCATTEROMETER DATA
INDICATED VERY LIGHT WINDS OF 5 TO 10 KNOTS MOST AREAS.
SCATTERED MODERATE TO STRONG CONVECTION WAS CONFINED TO NEAR THE
WEST COAST OF FLORIDA...INLAND OVER THE CENTRAL GULF COAST AND
OVER THE NORTHWEST YUCATAN. ISOLATED CLUSTERS OF CONVECTION WAS
NOTED OVER THE BAY OF CAMPECHE. PATCHES OF CUMULIFORM CLOUDS
WERE NOTED OVER THE REMAINDER OF THE GULF.

...CARIBBEAN SEA...

MID-TO UPPER LEVEL WEST-NORTHWEST FLOW PREVAILED OVER THE FAR
NORTHERN CARIBBEAN E OF 80W COURTESY OF AN ELONGATED CYCLONIC
CIRCULATION OVER THE SW N ATLANTIC NEAR THE BAHAMAS. THE
CYCLONIC FLOW ASSOCIATED WITH THE CIRCULATION OVER THE GULF HAS
MOVED W OF THE AREA AND WAS REPLACED BY A NARROW SHORTWAVE RIDGE
ALONG 83W. THE FLOW BECOMES WESTERLY OR SOUTHWESTERLY OVER THE
REMAINDER OF THE CARIBBEAN SEA WITH WATER VAPOR IMAGERY SHOWING
SIGNIFICANT SUBSIDENCE IN THE AREA. VERY DIFFLUENT FLOW WAS NOTED
OVER THE FAR W CARIBBEAN AND THE GULF OF HONDURAS WHICH COUPLED
WITH OROGRAPHIC LIFT  MAINTAINED SCATTERED MODERATE TO STRONG
CONVECTION OVER NICARAGUA...HONDURAS...BELIZE AND MOST OF THE
YUCATAN PENINSULA. ADDITIONAL AREAS OF STRING CONVECTION WERE
NOTED OVER PORTIONS OF CENTRAL AND EASTERN CUBA.

AT THE SURFACE MODERATE TO FRESH EASTERLY WINDS WERE NOTED OVER
THE AREA N OF 17N WITH STRONG TO NEAR GALE FORCE WINDS NOTED
OVER THE AREA S OF 17N BETWEEN 70W AND 80W. A GALE WARNING IS IN
EFFECT FOR THE COASTAL AND OFFSHORE WATERS OF COLOMBIA...FROM
11.5N TO 16N BETWEEN 70W AND 80W.

...HISPANIOLA...

MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW SURROUNDS
HISPANIOLA...THANKS TO THE CYCLONIC CIRCULATION CENTER OVER THE
SW N ATLANTIC AND THE BAHAMAS.

THE GFS MODEL FORECAST FOR 250 MB SHOWS THAT WESTERLY WIND FLOW
WILL COVER HISPANIOLA WITH THE CURRENT CYCLONIC CIRCULATION
CENTER...TO BE TO THE NORTH AND NORTHWEST OF HISPANIOLA. THE GFS
MODEL FORECAST FOR 500 MB SHOWS THAT SOUTHERLY WIND FLOW WILL
CROSS HISPANIOLA FOR THE NEXT 48 HOURS...WITH A NORTHEAST-TO-
SOUTHWEST ORIENTED RIDGE.

THE ATLANTIC OCEAN...

A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS
NEAR 24N75W...NEAR THE CENTRAL BAHAMAS. THE CYCLONIC CENTER IS
COMPARATIVELY NOT AS WELL DEFINED AS IT HAS BEEN FOR THE LAST
FEW DAYS. A SECOND CENTER WAS LOCATED NEAR 25N68W...WITH THE TWO
CENTERS FORMING A BROAD CYCLONIC GYRE OVER THE SUBTROPICAL ATLC
W OF 63W. THE ASSOCIATED CYCLONIC FLOW EXTENDS INTO THE
CARIBBEAN SEA AND THE ATLANTIC OCEAN FROM 16N IN THE CARIBBEAN
SEA...TO 30N IN THE ATLANTIC OCEAN...BETWEEN 60W AND 82W.

PATCHES OF BROKEN TO OVERCAST MULTILAYERED CLOUDS COVER THE AREA
FROM 22N TO 30N BETWEEN 72W AND THE COAST OF THE U.S. A MID-TO
UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC CIRCULATION NEAR
30N37W THROUGH 24N47W TO 21N55W. THE TROUGH IS SURROUNDED BY
COMPARATIVELY DRIER AIR IN SUBSIDENCE AS NOTED IN WATER VAPOR
IMAGERY.

THE EUMETSAT SEVERI SAL AND AIRMASS PRODUCTS INDICATED A VAST
AREA OF DRY AIR AND SAHARAN DUST OVER A BROAD SECTION OF THE
TROPICAL AND SUBTROPICAL ATLANTIC E OF 53W...ONE OF THE LARGEST
AREAS OBSERVED THIS SEASON.

A SURFACE RIDGE EXTENDS FROM THE MADEIRA ARCHIPELAGO...TO
26N25W...TO A 1028 MB HIGH PRESSURE CENTER THAT IS NEAR
27N41W...TO 27N66W...BEYOND CENTRAL FLORIDA...INTO THE GULF OF
MEXICO.

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

$$
COBB


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