HURRICANE

Special Features

Heavy Rainfall over the southeastern Gulf of Mexico, portions of the Florida Peninsula, and the western Atlantic:

Abundant tropical moisture is surging northward from the western Caribbean, across the southeastern Gulf of Mexico, also over portions of Florida, and across the adjacent western Atlantic waters. This moisture resides to the southeast of a surface trough that extends from near 30.5N78W southwestward to east- central Florida north of Cape Canaveral to an elongated area of low pressure (Invest AL90) near 30N79.2W with a pressure of 1010 mb. A surface trough continues from this elongated area of low pressure southwestward to near Tampa, Florida to 24N88W and to the central Bay of Campeche. Also, upper-level diffluent flow is present across the region. As a result, numerous showers and scattered thunderstorms are present southeast of the trough over the western Atlantic from 27.5N to 31N between 73W and 80W and south of 25N west of 77W including the Straits of Florida, the majority of the Florida Key, over central Cuba and its adjacent waters. In addition numerous thunderstorms are quickly developing over the Yucatan Peninsula and the Bay of Campeche south of 22N. Cloud to surface lightning, strong gusty winds, rough seas and low visibility are ongoing within this convective activity over these areas. The shower and thunderstorm activity is expected to continue across the region through at least Fri. Mariners transiting these regions should exercise caution. Please refer to bulletins and forecasts from your local weather forecast offices for specific local information.

Heavy Rainfall over Central America and Mexico: A barotropic Central American Gyre (CAG) is rapidly developing. Observations are indicating that heavy rainfall is already occurring before the main event that is forecast to begin Sunday morning, June 16 through the morning of Friday June 21. The persistence of moist onshore flow in the Pacific basins of Guatemala, Chiapas, Honduras and in El Salvador will favor 3-4 days of intermittent rounds of heavy precipitation.

Tropical Waves

A central Atlantic tropical wave has its axis along 32W from 03N to 12N. It is moving westward near 15 kt. No significant convection is depicted with this tropical wave.

An Atlantic tropical wave has its axis along 48W from 02N to 14N, moving westward at about 15 kt. Scattered convection is depicted from 00 to 06N between 44W and 49W.

A Atlantic tropical wave has its axis along 61W south of 12N eastern Venezuela. It is moving west at 10 to 15 kt. Scattered showers are near the wave axis south of 12N.

A western Caribbean tropical wave has its axis along 81W south of 14N, moving westward at 5 to 10 kt. Related numerous moderate to scattered strong convection is depicted south of 12N and east of 81W and over the eastern Pacific near the coast of Panama.

Monsoon Trough/ITCZ

The monsoon trough axis extends from near 13.5N17W to 08N26W. The ITCZ begins at 08N26W and continues to near 08N31W, and from 08.5N34W to 07N47W, and from 08N51W to 08.5N58W. Numerous moderate to strong convection emerging off West Africa and extends from 03N to 10N between the coast and about 22W. This convection is most likely in advance of the next tropical wave.

Gulf Of Mexico

Please read the Special Features section for information about the ongoing heavy rainfall over the southeastern Gulf of Mexico and the upcoming rainfall event over Mexico.

A stationary front extends from northeast Florida to just south of Louisiana, and westward from there to inland Texas near Houston/Galveston area. A trough extends from near Tampa Bay, Florida to the central Bay of Campeche. Scattered to numerous showers and thunderstorms are southeast of the trough impacting most of the southeastern Gulf and waters just offshore the northern Yucatan Peninsula. Outside of convection, light to gentle generally variable winds west of the trough, with moderate south to southwest winds east of the trough. Seas are 1 to 3 ft west of the trough, and 3 to 4 ft east of the trough, except to 5 ft near the Yucatan Channel due to a southeast swell. Hazy conditions are over the SW Gulf due to ongoing agricultural fires are in Mexico.

For the forecast, the aforementioned surface trough is expected to gradually weaken through late Fri. Looking ahead, a broad area of low pressure is forecast to form over the southwestern Gulf of Mexico this weekend or early next week. Environmental conditions appear conducive for gradual development of this system, and a tropical depression could form during the early or middle part of next week while it moves slowly westward or west- northwestward. Increasing winds and building seas are expected with this system.

Caribbean Sea

Please read the Special Features section above for more information about the upcoming Rainfall event over Central America and Mexico.

Numerous moderate to isolated strong convection is depicted at this time north of 17.5N between 18W and 82W due to a surge of tropical moisture. Outside of convection, the pressure gradient between Atlantic high pressure, lower pressures in the deep tropics, and the trough of low pressure across the southeastern Gulf of Mexico is resulting in moderate to fresh east to southeast winds over most of the basin, with the exception of the central basin, where winds are fresh to strong, including between Cuba and Jamaica. Seas range from 7 to 9 ft over the central Caribbean and 4 to 6 ft elsewhere, except 3 to 5 ft east over the southwestern Caribbean.

For the forecast, high pressure located NE of the area combined with the Colombian low and the passage of tropical waves will support fresh to strong trade winds across the central Caribbean through tonight. Moderate to fresh southeast winds are expected over the northwestern Caribbean likely through Fri as a trough of low pressure remains over the eastern Gulf of Mexico. Otherwise, scattered showers and thunderstorms are forecast to continue across portions of the northwestern Caribbean through the rest of the week as a surge of tropical moisture persists across the region. Looking ahead, expect increasing winds and building seas over the western Caribbean, including the Gulf of Honduras, over the upcoming weekend as a broad area of low pressure is forecast to form over the southwestern Gulf of Mexico.

Atlantic Ocean

Please read the Special Features section above for more information about the heavy rainfall over the western Atlantic and near and over portions of the Florida peninsula.

A stationary front extends from low pressure of 1017 mb that is well north of the area near 37N61W southwestward to just north of the Florida Georgia line. Deep convection over the western Atlantic is described above in the Special Features section. Fresh to locally strong winds and 5 to 7 ft seas are north of 28.5N to 31N between 73W and 77.5W. A surface trough supported by an upper-level is analyzed from near 30N46W to 26N45W and to 20N48W. Broken to overcast mostly mid-level clouds with embedded with scattered showers and thunderstorms are depicted from 21N to 29N between 42W and 47.5W. A weak trough extends from 22N54W to 16.5N60W. Scattered moderate convection is depicted from 21N to 22.5N between 50W and the trough axis. Another weak surface trough is analyzed from 29N60.5W to 21N59W. Scattered moderated convection is depicted from 21N to 25N between the trough axis and 56W

Other than the features above, strong high pressure of 1033 mb located well north of the discussion area in the vicinity of the Azores has an associated ridge that reaches southwestward to the central Bahamas, disrupted by the troughs. Mainly gentle to moderate winds and seas of 3 to 6 ft seas dominate the basin west of 35W. Moderate to fresh trade winds east of 35W, except for fresh to strong northeast winds from the Cabo Verde Islands to the Canary Islands, including along the coast of Africa. Seas are 5 to 7 ft across this area. Saharan Air dominates the lower to middle atmosphere across the Atlantic from about 10N to 20N and roughly between Africa and the Lesser Antilles.

For the forecast west of 55W, an elongated area of low pressure offshore the coast of Florida is producing a large area of disorganized showers and thunderstorms. Despite strong upper- level winds, some gradual development is possible while the system moves northeastward offshore of the southeastern U.S. Coast during the next couple of days. The showers and thunderstorms will be numerous in coverage and contain gusty winds and frequent lightning at times over most of the western part of the forecast waters, mainly W of a line from 31N70W to the central Bahamas. Expect for little change with this convective activity through at least Fri. Fresh to strong southerly winds are expected over the western Atlantic ahead of this system during the next couple of days. As the low pressure departs, high pressure will build southward over the western Atlantic beginning this weekend and into early next week.

Posted 3 hours ago by NHC Forecaster Krv