[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211052
TWDAT

TROPICAL WEATHER DISCUSSION...
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON APR 21 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING
INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL
ANALYSIS...WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...THE ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N10W 3N20W 3N30W 2N40W TO THE
EQUATOR AT 50W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM N
OF THE AXIS BETWEEN 27W-43W. ISOLATED MODERATE CONVECTION IS
WITHIN 120 NM N OF THE AXIS BETWEEN 22W-27W AND WITHIN 300 NM N
OF THE AXIS W OF 43W.

...DISCUSSION...

GULF OF MEXICO...
A MID TO UPPER LEVEL RIDGE IS BUILDING E OVERTAKING TROUGHING
ASSOCIATED WITH AN UPPER LOW SPINNING OVER NORTH CAROLINA. THIS
UPPER CUT OFF IS PROVIDING LIMITED SUPPORT FOR A SLOW MOVING
FRONT FROM SOUTHWEST FLORIDA TO 26N87W. THE FRONT IS ONLY MARKED
BY A NARROW BROKEN LINE OF LOW CLOUDS WITH EMBEDDED ISOLATED
SHOWERS. A VERY WEAK 1016 MB HIGH IS SITUATED BEHIND THE FRONT
CENTERED OVER THE NE WATERS NEAR 29N85W. MAINLY FAIR WEATHER AND
LIGHT TO MODERATE WINDS DOMINATE THE MAJORITY OF THE REGION
SUPPORTED BY A SUBSIDENT ENVIRONMENT...ESPECIALLY OVER THE SW
PORTION. THE FRONT IS EXPECTED TO CONTINUE WEAKENING AS IT
SHIFTS E ALLOWING FAIR WEATHER TO CONTINUE OVER THE NEXT DAY OR
TWO.

CARIBBEAN SEA...
A BROAD UPPER TROUGH LIES OVER THE CARIBBEAN SEA AND FLAT
RIDGING COVERS MUCH OF THE TROPICAL ATLC AND SOUTH AMERICA. THIS
LARGE SCALE PATTERN IS PRODUCING A MODERATE TO STRONGLY
SUBSIDENT ENVIRONMENT N OF 14N. S OF 14N...THE ATMOSPHERE IS
BEING SOMEWHAT MOISTENED ALOFT BY THIN BROKEN HIGH LEVEL CLOUDS.
IN THE LOWER LEVELS...AN EARLIER QSCAT PASS SUGGESTS THAT NE
WINDS HAVE DECREASED TO 20-25 KT NEAR THE COAST OF COLOMBIA WITH
MODERATE TRADES NOTED ELSEWHERE. THE TYPICAL LOW-LEVEL CLOUD
PATCHES REMAIN SUBDUED THIS MORNING WITH THE ONLY ORGANIZED
PATCH OVER THE NRN LEEWARD ISLANDS. THE TRADE WIND FLOW IS
EXPECTED TO WEAKEN FURTHER LATER TODAY AS TROUGHING BECOMES
BETTER ESTABLISHED OVER THE W ATLC. OTHERWISE...LITTLE
SIGNIFICANT CHANGE IS EXPECTED OVER THE NEXT DAY OR SO.

ATLANTIC OCEAN...
A LARGE SCALE UPPER TROUGH...WITH A FEW EMBEDDED SHORTWAVES
...COVERS MUCH OF THE W ATLC. AN EMBEDDED UPPER LOW OVER NORTH
CAROLINA IS PROVIDING SOME SUPPORT FOR A WEAKENING FRONT FROM
32N76W TO S CENTRAL FLA. DOPPLER RADAR AND LIGHTNING DATA IS
DETECTING QUITE A BIT OF TSTM ACTIVITY ALONG THE BOUNDARY N OF
THE DISCUSSION ZONE...HOWEVER...ONLY ISOLATED SHOWERS AND TSTMS
ARE LIKELY WITHIN 60 NM E OF THE FRONT S OF 32N. SCATTERED
SHOWERS AND TSTMS ARE ALSO LOCATED FROM 22N-31N BETWEEN 53W-65W.
THIS ACTIVITY IS ASSOCIATED WITH BASE OF THE SHARP UPPER TROUGH
(VORTICITY MAX)...UPPER DIFFLUENCE AND LOW-LEVEL CONVERGENCE
ALONG A LINGERING SFC TROUGH ALONG 32N52W 27N59W 23N66W.

THE CENTRAL AND EASTERN ATLC IS DOMINATED BY A QUASI-STATIONARY
1023 MB HIGH NEAR 30N32W. THIS HIGH IS PRODUCING A LARGE AREA OF
15-20 KT NE/E WINDS ACROSS THE TROPICAL BELT AND 20-25 KT N TO
NE WINDS NEAR THE COAST OF AFRICA FROM 15N-25N...DUE TO INVERTED
TROUGHING OVER THE CONTINENT. IN THE MID AND UPPER LEVELS...A
BROAD RIDGE COVERS MUCH OF THE REGION BETWEEN 25W-50W AND UPPER
TROUGHING LIES OVER THE THE NE PORTION FROM THE MADEIRA ISLANDS
TO 17N32W. DIFFLUENCE ALOFT TO THE E OF THE TROUGH AXIS IS
GENERATING/TRANSPORTING MID-HIGH LEVEL CLOUDS WITHIN 300 NM E OF
THE TROUGH LINE...INCLUDING THE CAPE VERDE ISLANDS. BROAD FLAT
RIDGING LIES OVER THE TROPICS ENHANCING CONVECTION IN THE ITCZ W
OF 25W.

$$
CANGIALOSI


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