Tropical Waves

The axis of a tropical wave is near 36W-37W, S of 15N, moving west at around 15 kt. Nearby convection is discussed in the MONSOON TROUGH/ITCZ section below.

The axis of a tropical wave is near 47W, S of 16N, moving westward at around 15 kt. Nearby convection is discussed in the MONSOON TROUGH/ITCZ section below.

The axis of a tropical wave is near 59W, S of 18N, moving westward at around 15 kt. Scattered moderate convection is noted from 06N to 11N between 53W and 57W.

The axis of a tropical wave previously along 77W has shifted NW across the Caribbean, and is becoming absorbed in the monsoonal circulation across Central America and southeastern Mexico. This wave has therefore been dropped from the 1800 UTC surface analysis.

Monsoon Trough Itcz

The monsoon trough extends off the coast of Africa near 12N16W and extends SW to 08N21W. The ITCZ extends from 08N21W to 05. 5N36W, then from 05N38W to 04. 5N46W, then from 04. 5N48W to 04. 5N52W. Scattered moderate convection is noted from 03. 5N to 10N between 14W and 34W. Scattered moderate isolated strong convection is noted from 02N to 10N between 36W and 59W.

Gulf Of America

A surface ridge continues from 1022 mb high over Georgia southwestward across the northern Gulf. The pressure gradient between this ridge and lower pressure around TS Cristina and the eastern Pacific monsoon circulation is supporting moderate to locally fresh E-SE winds over the waters S of 26NW, while gentle to moderate winds prevail N of 26N. Seas are in the 4-5 ft range across SW portions and 2-4 ft elsewhere. Scattered moderate convection covers the waters from the Yucatan Channel to the Florida Panhandle.

For the forecast, a surface ridge across the northern Gulf will continue to dominate the region the next few days, supporting gentle to moderate east to southeast winds over the eastern Gulf, and moderate to fresh winds in the western Gulf through much of this week. Slight to moderate seas will also prevail. The exception will be off the Yucatan Peninsula, where a diurnal trough will support fresh E winds pulsing to strong speeds during the evenings through Wed. A trough or weak low pressure center may emerge from the Yucatan Peninsula into the Bay of Campeche on Thu through Fri night, accompanied by numerous showers and thunderstorms along with fresh to strong winds and building seas.

Caribbean Sea

Moderate trade winds prevail across the basin E of 68W, while moderate to fresh E-SE trades and moderate seas prevail across the remaining Caribbean waters. Seas are 3 to 5 ft E of 68W and 4 to 7 ft W of 68W. The interaction of a diffuse tropical wave and upper level troughing is supporting scattered active convection over much of the western waters W of 75W.

For the forecast, the pressure gradient between the western Atlantic ridge and T. S. Cristina and the Eastern Pacific monsoonal circulation will strengthen slightly the next few days as high pressure moves into the W Atlantic, leading to widespread moderate to fresh trades with fresh to strong E winds in the central and NW Caribbean, including the Gulf of Honduras. These conditions will prevail through the forecast period. In addition, a trough or weak low pressure center may emerge from the Yucatan Peninsula into the Bay of Campeche on Thu through Fri night, maintaining a tight pressure gradient over the NW Caribbean and the Gulf of Honduras. Elsewhere, moderate to fresh winds and mostly moderate seas will prevail.

Atlantic Ocean

A surface trough extends from 27N72W to eastern Cuba. Another deep layered trough is analyzed from 31N60W to 23N69W. Scattered showers and isolated thunderstorms are within 300 nm E of the second trough. A front has become stationary along about 31N to the N and NW of these troughs. Gentle to locally moderate NE to E winds prevail across most of the area W of the second trough, with seas 4 ft or less. High pressure dominates the remainder of the discussion waters N of 20N, anchored by a 1032 mb high centered SW of the Azores near 36N34W. Moderate or weaker anticyclonic winds, and slight to moderate seas, are N of 20N and W of 50W. Fresh to strong winds are N of 20N and E of 30W, where seas are in the 7-9 ft range. Moderate to fresh winds, and seas 5 to 8 ft prevail elsewhere S of 20N.

For the forecast west of 55W, a deep layered surface trough extending from 31N60W to 23N69W will remain nearly stationary through midweek, supporting continued showers and thunderstorms in the region. A weak front will move across the northern waters tonight, then move very slowly or stall on Wed, gradually dissipating by Thu. A weak cold front will follow, only reaching as far south as about 27N before stalling and moving eastward or dissipating. High pressure north of the area and in the wake of the front will shift eastward through the end of the week while weakening, with the associated ridge extending toward Florida and southeastern Georgia. The related pressure gradient between this high and lower pressures in the tropics will generally allow for gentle to moderate winds N of 20N and moderate to fresh trades S of 20N, along with slight to moderate seas. Increasing moisture resulting in unsettled weather conditions is likely to impact the far western section of the basin during the week.

Posted about 2 hours ago by NHC Forecaster Stripling