textproduct: Key West

FORECAST

The low level ridge is slowly sliding eastward and was evident by the the subtle height rises below 500 mb in tonight's sounding. In addition, there continues to be a surge in moisture with very little dry air still left in the column. In fact last night's sounding came in with a PWat of 1.71 inches, which is well above the 90th percentile for this time of year. Despite this influx of moisture, aloft we remain wholly situated under the ridge and therefore still too stable to get much in the way of vertical growth.

Looking upstream though, there are two main regions where convection is occurring this hour. The first is associated with a potent shortwave moving across the northeast Gulf coast. Convection extends southward along a subtle surface boundary. These features and the associated convection will lift northeast into the Florida Panhandle later today.

The second area, and the one that will be of most concern to us, is currently across the Yucatan Peninsula. Here a shortwave has ejected out of a trough located across central Mexico and is firing isolated convection. This shortwave will trek northeast today as it rides along the periphery of the upper level ridge in the Caribbean. That being said, it looks to lose some of it's definition by the time it reaches our area. Therefore, have trimmed thunder chances to the southwest Straits of Florida just for the daytime period of Thursday. The aforementioned trough across central Mexico will phase with the next trough dipping out of the Central U.S. tonight and will shift closer to our area. We remain somewhat in the right jet entrance of the upper level jet. In addition, we will be on the western side of the low level ridge, which will initially keep an east to southeast wind. This will allow for some veering to occur under the upper level trough. The ingredients are there for thunder but it remains to be seen how well organized storms may be. Regardless, the "best" alignment looks to occur across the Straits of Florida and therefore will carry the highest chances for thunder at this time.

This ridge/trough combo will hold across the area through the end of the week and into the first part of the weekend. Thereafter it will finally lift out and calmer weather will return. Deep layer ridging will slide back in towards midweek next week and a return to typical dry season weather can be expected. As a teaser, there is good consensus in the models that we could see another cold front towards the end of the week. Stay tuned.

MARINE

Issued at 415 AM EST Thu Dec 26 2024

High pressure building in to the eastern U.S. will help to maintain moderate northeasterly to easterly breezes through tonight. Thereafter, a surge of moisture from our south will encourage unsettled weather with the greatest likelihood of rain and thunderstorms on Friday and Saturday. Hazards to mariners may include, but are not limited to, occasional lightning strikes, gusty and erratic winds, and reduced visibility from heavy downpours. While these hazards will be possible virtually anywhere across the Keys waters, the highest likelihood is across portions of the Straits of Florida. Conditions are expected to improve sometime from later Saturday or early Sunday, and through the beginning of next week.

AVIATION

(06Z TAFS) Issued at 415 AM EST Thu Dec 26 2024

VFR conditions will prevail at both EYW and MTH through the TAF period. Isolated showers could pass over the island chain throughout today but confidence in timing and direct impact leaves mention out of the TAFs for the time being. Near surface winds will be northeast to east at near 10 knots.

CLIMATE

On this day in 1983, the daily record low temperature of 39F was recorded in Marathon. Marathon temperature records date back to 1950.

PRELIMINARY POINT TEMPS/POPS

Key West 79 71 78 71 / 30 50 50 40 Marathon 78 71 78 71 / 20 50 50 40

KEY WATCHES/WARNINGS/ADVISORIES

FL...None. GM...None.