[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN JUN 14 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...

A SHARP TROUGH OF SURFACE LOW PRESSURE ACROSS THE YUCATAN
PENINSULA AND SOUTHERN GULF IN COMBINATION WITH AN UPPER-LEVEL
LOW OVER THE GULF OF MEXICO...CONTINUES TO PRODUCE SHOWERS AND
THUNDERSTORMS OVER PORTIONS OF GUATEMALA...BELIZE...THE
YUCATAN...AND ADJACENT WATERS. UPPER LEVEL WINDS ARE EXPECTED TO
BECOME MORE FAVORABLE FOR SOME DEVELOPMENT OVER THE NEXT DAY OR
TWO AS THE SYSTEM MOVES NORTHWESTWARD INTO THE WESTERN GULF OF
MEXICO. HEAVY RAINFALL IS EXPECTED TO CONTINUE OVER THESE AREAS
TODAY...ALONG WITH WINDS TO NEAR GALE FORCE OVER PORTIONS OF THE
NORTHWESTERN CARIBBEAN SEA AND THE SOUTHEASTERN GULF OF MEXICO.
AN AIR FORCE RESERVE HURRICANE HUNTER IS SCHEDULED TO
INVESTIGATE THE SYSTEM THIS AFTERNOON. ADDITIONAL INFORMATION
ABOUT THIS FEATURE IS FOUND IN THE HIGH SEAS FORECAST UNDER WMO
FZNT02 KNHC OR MIAHSFAT2. THE CHANCES OF THIS SYSTEM DEVELOPING
INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS MEDIUM.

A TIGHT PRESSURE GRADIENT BETWEEN CENTRAL ATLC HIGH PRESSURE AND
LOWER PRESSURES OVER S AMERICA SUPPORTS GALE FORCE WINDS S OF 12
N BETWEEN 70W AND 72W...INCLUDING THE GULF OF VENEZUELA. SEAS TO
8 FEET ARE POSSIBLE. WINDS ARE EXPECTED TO DROP BELOW GALE FORCE
BY 1800 UTC TODAY. SEE THE LATEST HIGH SEAS FORECAST UNDER WMO
FZNT02 KNHC OR MIAHSFAT2 FOR MORE DETAILS.

...TROPICAL WAVES...

AN EASTERN ATLANTIC TROPICAL WAVE HAS EMERGED OFF THE AFRICAN
COAST AND EXTENDS ALONG 16W/17W FROM 11N TO 5N MOVING WESTWARD
AT AROUND 20 KT. SSMI TPW INDICATES A LARGE AREA OF DEEP
MOISTURE IN THE WAVE ENVIRONMENT. SATELLITE ENHANCEMENTS SHOW A
LARGE AREA OF SAHARAN DUST SURGING WESTWARD TO THE NORTH OF THE
WAVE. SCATTERED MODERATE CONVECTION IS FROM 05N TO 13N BETWEEN
12W AND 25W.

A CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 41W/42W FROM 16N TO
06N...MOVING WESTWARD AT 15 TO 20 KT OVER THE PAST 24 HOURS.
MODEL GUIDANCE DEPICTS A 700 MB TROUGH IN THE ENVIRONMENT OF
THIS WAVE. TPW SSMI IMAGERY SHOWS THAT A DEEP MOIST ENVIRONMENT
PREVAILS FROM 04N TO 15N. SAHARAN DUST IS NOTED N OF 15N.
ISOLATED MODERATE CONVECTION IS FROM 08N TO 11N BETWEEN 42W AND
44W.

A CENTRAL ATLANTIC TROPICAL WAVE IS ALONG 51W/52W FROM 14N TO
05N...MOVING WESTWARD AT 15 TO 20 KT OVER THE PAST 24 HOURS.
SAHARAN DUST IS ALSO ALONG THE NORTHERN HALF OF THIS WAVE WHICH
IS INHIBITING SIGNIFICANT CONVECTIVE PRECIPITATION OVER THIS
AREA MAINLY TO THE NORTH OF 11N. SCATTERED MODERATE CONVECTION
IS FROM 05N TO 11N BETWEEN 51W TO 61W.

A CENTRAL CARIBBEAN SEA TROPICAL WAVE IS ALONG 74W/75W FROM
HAITI NEAR 19N SOUTHWARD TO NORTHERN COLOMBIA. THE WAVE IS
MOVING WESTWARD AT 15 TO 20 KT OVER THE PAST 24 HOURS. TOTAL
PRECIPITABLE WATER IMAGERY SHOWS THAT THIS WAVE IS EMBEDDED IN
RELATIVELY DRY AIR. THERE IS ALSO A BROAD SAHARAN AIRMASS
PREVAILING ACROSS THE EASTERN CARIBBEAN INHIBITING ANY
CONVECTION. NO DEEP CONVECTION IS NOTED WITH THIS WAVE.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH ENDS BEFORE CROSSING THE AFRICAN COAST AS A
TROPICAL WAVE EXITS THE COASTAL REGIONS OF THE CONTINENT TODAY.
THE ITCZ BEGINS NEAR 07N21W AND CONTINUES THROUGH 06N30W TO
08N41W...THEN CONTINUES WEST OF A TROPICAL WAVE FROM 08N44W TO
07N51W. OTHER THAN CONVECTION DISCUSSED IN THE TROPICAL WAVES
SECTION...ISOLATED MODERATE CONVECTION IS WITHIN 100 NM OF THE
ITCZ AXIS BETWEEN 24W AND 36W.

...DISCUSSION...

THE GULF OF MEXICO...

A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 25N90W WITH
CYCLONIC FLOW ALOFT OVER THE SOUTHERN GULF OF MEXICO. UPPER
LEVEL RIDGING COVERS THE NORTHERN GULF. A SHARP TROUGH OF
SURFACE LOW PRESSURE EXTENDS FROM 25N88W TO THE YUCATAN
PENINSULA. GALE FORCE WINDS ARE OCCURRING OVER PORTIONS OF THE
SOUTHEASTERN GULF ASSOCIATED WITH THIS FEATURE. SEE THE SPECIAL
FEATURES SECTION ABOVE FOR MORE DETAILS. THIS TROUGH IS
INTERACTING WITH THE UPPER LEVEL LOW TO PRODUCE NUMEROUS
MODERATE TO STRONG CONVECTION FROM 22N TO 25N BETWEEN 84W AND
89W. UPPER LEVEL DIFFLUENCE OVER THE NE GULF SUPPORTS SCATTERED
THUNDERSTORMS FROM 25N TO THE NORTHERN GULF COAST BETWEEN 83W
AND 91W. ASIDE FROM THE STRONGER WINDS NEAR THE SPECIAL
FEATURE...SOUTHEASTERLY SURFACE WINDS OF 15 TO 20 KT DOMINATE
THE BASIN. OVER THE NEXT 24 HOURS THE SPECIAL FEATURE WILL MOVE
NORTHWESTWARD OVER THE CENTRAL GULF TOWARD THE NW GULF. EXPECT
NUMEROUS AREAS OF CONVECTION TO SPREAD ACROSS THE CENTRAL GULF
TO NW GULF THROUGH MONDAY...ALONG WITH AREAS OF GALE FORCE
WINDS.

THE CARIBBEAN SEA...

CONVECTION AND GALE FORCE WINDS OVER THE EXTREME NORTHWESTERN
PORTION OF THE CARIBBEAN IS ASSOCIATED WITH A SHARP TROUGH OF
SURFACE LOW PRESSURE OVER THE YUCATAN PENINSULA AND GULF OF
MEXICO. A STRONG PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER
THE CENTRAL ATLC AND LOWER PRESSURE OVER S AMERICA IS SUPPORTING
GALE FORCE WINDS OVER THE GULF OF VENEZUELA. PLEASE SEE THE
SPECIAL FEATURES SECTION FOR MORE DETAILS. A TROPICAL WAVE IS
OVER THE CENTRAL CARIBBEAN. PLEASE SEE THE TROPICAL WAVES
SECTION FOR MORE DETAILS. SAHARAN DUST WITH RELATIVELY DRY AIR
COVERS THE CENTRAL AND EASTERN CARIBBEAN EAST OF 82W. ASIDE FROM
THE AREAS WITH GALE FORCE WINDS...15 TO 25 KT TRADE WINDS COVER
MOST OF THE REMAINDER OF THE CARIBBEAN WITH AN AREA OF WINDS
AROUND 30 KT FROM 11N TO 15N BETWEEN 70W AND 80W. OVER THE NEXT
24 HOURS CONVECTION AND WINDS WILL DECREASE OVER THE
NORTHWESTERN CARIBBEAN AS THE SPECIAL FEATURE LIFTS NW ACROSS
THE GULF OF MEXICO. A TROPICAL WAVE APPROACHING THE LESSER
ANTILLES MAY BRING CONVECTION TO THE ISLANDS BY MONDAY NIGHT.

...HISPANIOLA...

SAHARAN DUST IS BEING OBSERVED OVER THE ISLAND TODAY IN ADDITION
TO RELATIVELY DRY AIR IN THE LOW LEVELS. THESE FACTORS ARE
HELPING TO INHIBIT SHOWER AND THUNDERSTORM ACTIVITY OVER THE
ISLAND TODAY. AN ISOLATED SHOWER OR THUNDERSTORM CANNOT BE RULED
OUT THIS AFTERNOON AND MONDAY AFTERNOON. OTHERWISE...EXPECT
GENERALLY FAIR CONDITIONS THROUGH MONDAY NIGHT.

THE ATLANTIC OCEAN...

A WEAK 1020 MB HIGH IS CENTERED NEAR 29N76W. UPPER LEVEL RIDGING
JUST TO THE NORTH OF THIS SURFACE HIGH IS PRODUCING DIFFLUENCE
WHICH SUPPORTS ISOLATED MODERATE CONVECTION FROM 30N TO 32N
BETWEEN 74W AND 78W. AN UPPER LOW IS CENTERED NEAR 28N59W WITH A
TROUGH AXIS EXTENDING SOUTHWESTWARD TO NEAR THE TURKS AND
CAICOS. DYNAMIC LIFT ASSOCIATED WITH THE TROUGH SUPPORTS WIDELY
SCATTERED MODERATE CONVECTION FROM 23N TO 26N BETWEEN 63W AND
73W. A NEARLY STATIONARY 1023 MB SURFACE HIGH IS CENTERED NEAR
28N53W. FARTHER EAST...A SURFACE TROUGH EXTENDS FROM 29N42W TO
24N44W. NO DEEP CONVECTION IS NOTED WITH THIS TROUGH. A 1026 MB
HIGH CENTERED NEAR 31N33W DOMINATES THE EASTERN ATLC WITH
ANTICYCLONIC FLOW AND GENERALLY FAIR WEATHER FROM 15N TO 32N
EAST OF 55W.

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

$$

LATTO
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