Monsoon Trough Itcz

The monsoon trough enters the Atlantic from a 1011 mb low analyzed at the coast of Guinea near 11N15W and then extends to 04N21W and then to 04N26W. The ITCZ then extends from 04N26W to 03N39W and then to 09N61W. Numerous moderate to strong convection is observed S of 12N and E of 30W. Scattered moderate convection is also seen from 07N to 11N between 50W and 58W.

GULF OF AMERICA,

A stationary front extends from the Big Bend of Florida to near 29N86W where it becomes a warm front. The warm front then bends westward and southward into the SW Gulf near 21N96W, followed then by another stationary front that extends southward to the Mexican coast between Veracruz and Minatitlan. Scattered moderate convection is observed from 24N to 26N between 93W and 95W, with widely scattered showers seen north and west of these frontal boundaries. Scatterometer data from 1505 UTC indicated a weak surface low forming along the front near 25N95W, with locally fresh to strong winds in cyclonic flow surrounding the low. Moderate to fresh NE winds prevail north of the frontal boundaries, with moderate or weaker S to SE winds south of the fronts. Slight seas prevail across the Gulf.

For the forecast, a cold front extends from the Florida Big Bend to 28. 5N87W, then becomes nearly stationary to 26N94W to just S of Veracruz, Mexico. A few clusters of showers continue along and behind the stationary portion of the front. Moderate or weaker winds and moderate seas prevail N and W of the front and will persist into Sun afternoon. A new cold front is expected to enter the NW Gulf Sun evening and overtake the current front, while sweeping across the basin into early next week. This will lead to fresh to strong N to NW winds and building seas in the wake of the front. Gale-force NW to N winds may develop off Veracruz Mon afternoon and evening. Winds and seas will diminish Tue into Wed as the front stalls across the NW Caribbean and W Cuba.

CARIBBEAN SEA,

A cluster of showers associated with a weak surface trough are moving across the western Caribbean, with convection observed from 12N to 18. 5N and W of 80W. Elsewhere across the basin, the pressure gradient between the Colombia low and higher pressure to the north drives fresh to strong trades across the central Caribbean and moderate to fresh trades in the eastern Caribbean. Much of the Caribbean W of 80W is seeing moderate or weaker trades prevail. Seas of 5-8 ft are prevalent E of 80W, with seas of 2-5 ft W of 80W.

For the forecast, a moderate pressure gradient between weak high pressure centered north of the Greater Antilles and lower pressures in northern South America will sustain moderate to fresh easterly trade winds and moderate seas over the central and eastern Caribbean through the middle of next week. Moderate or lighter winds and slight to moderate seas will prevail elsewhere. A persistent E-NE swell will support rough seas in the Atlantic passages of the Lesser Antilles through the forecast period. Looking ahead, a weakening cold front will approach the northwestern Caribbean on Tue and linger across the area through Wed. High pressure will build in by the middle of next week, leading to strong winds and rough seas in the south- central Caribbean into late next week.

ATLANTIC OCEAN,

A stationary front extends from 31N77W to the NE FL coast. Moderate ot locally fresh winds prevail on both sides of the boundary with no notable convection nearby. In the central Atlantic, a frontal remnant trough extends from near 31N45W to 24N62W. Scattered showers and isolated thunderstorms are seen along and near the trough axis. A recent scatterometer pass indicated moderate to fresh SW winds ahead of this trough, N of 26N and out to about 35W. To the east, a weak 1019 mb low is analyzed near 30N35W. The surface winds around this low and ahead of a cold front to the north helping to maintain numerous moderate convection N of 30N between 31W and 43W. In the east Atlantic, a persistent upper level low embedded within a broad upper level trough is leading to a large area of scattered showers and isolated thunderstorms from 12N to 20N and E of 25W, as well as over the waters between the Canary Islands and the coast of Morocco.

Outside of convection, surface ridging prevails across much of the Atlantic. Fresh to strong trades and seas of 6-9 ft prevail across much of the basin S of 20N, as well as an area from 23N to the Canary Islands and E of 20W. Much of the Atlantic elsewhere and away from frontal boundaries is seeing moderate or weaker winds and moderate seas.

For the forecast west of 55W, a cold front has stalled across the far NW waters from 31N78W to near Palm Coast, Florida. Fresh to locally strong SW winds and moderate to rough seas are noted ahead of the front to 65W and north of 30N. These winds and seas will shift quickly eastward today into Sun, as the front begins to move eastward. The front will extend from near Bermuda to central Florida by early Sun morning and dissipate Sun evening. Looking ahead, a complex low pressure system and strong cold front will move through the northwestern tropical Atlantic by early next week, supporting widespread fresh to strong winds and building seas ahead of and behind the front Mon through Tue. The cold front will reach from near Bermuda to the NW Bahamas and Straits of Florida Mon evening, then weaken and stall along about 27N by Tue evening. Large N swell generated behind the front will diminish across the area waters on Wed.

$$ Adams Posted about 2 hours ago by NHC Forecaster