The morning water vapor imagery shows a building upper-air ridge over the Southern United States. Sinking air beneath it will bring pleasant weather conditions for the next 3 days. A front moved by the area during the wee hours of this morning and dewpoints are falling through the 50s and even into the upper 40s behind it. The morning balloon launch from Tallahassee confirms the arrival of this drier airmass, so it ought to feel more comfortable outside this afternoon. We expect the colder air to stay to our north. Highs are expected to reach the mid 70s in the far northern parts of our viewing area to the lower 80s in the Southeastern Big Bend and Suwannee River Valley.
A large dome of high pressure will move eastward through the Great Lakes and New England early this week. Even though its influence will reach all the way into the Gulf of Mexico, the pressure gradient between it and a developing low in the Southern High Plains will keep a breeze blowing. That means early morning lows will stay in the 50s, except for heavily-wooded, wind-protected areas. As the winds gradually veer to the east on Monday and the south on Tuesday, humidities will slowly creep higher (especially on Tuesday). Highs are still expected to approach 80 degrees away from the coast.
The next storm system is coming in the form of a potent trough is now diving southward along the Southern California coastline. This trough will be in Texas on Tuesday and kick out into the Southern U.S. on Wednesday. The Canadian global and American GFS models are still faster than the ECMWF; however, the former two model solutions have trended slower since yesterday. The UKMET is much slower, but it doesn't have a lot of support from the ensembles and has a tendency to be too slow in ejecting storms out of Texas or the Southwest U.S. As a result, I will continue to favor the extremely reliable ECMWF, but the GFS and Canadian models offer reasonable solutions, too. The forecast vertical profiles are showing a strongly sheared environment ahead of this trough -- greater than 60 knots in the lowest 6 km of the atmosphere and almost 40 knots in the lowest 1 km. However, middle atmospheric temperatures look quite warm, which would limit the overall degree of instability despite a warm and increasingly moist low-level environment. If instability remains weak per the current model guidance, then a line of showers and perhaps a couple of thunderstorms will move through our area. If even modest instability can develop, then there will be an increasing potential of damaging wind and maybe hail as the line moves through. Even though the severe weather threat is uncertain at this time, we believe some rain (amounts generally less than an inch) is highly probable and that's why we have high rain chances on Wednesday.
Unless the UKMET and one or two of the ensembles end up being right, weather conditions will improve once again on Thursday with temperatures at or above climatology.