It's turning out to be a busy afternoon in the Pinpoint Weather Center. We are monitoring two broad areas of rain and thunderstorms. The first is covering the eastern Gulf of Mexico, much of the Florida Peninsula, and even making it as far west as the Florida Big Bend and South-Central Georgia. The second area is a powerful line of thunderstorms stretching from the Mississippi-Alabama line southward across Louisiana. A weak impulse moved across the area this morning with little fanfare, but it did moisten up the atmosphere a little bit. That leaves the other two impulses (mentioned in yesterday's blog) which are the big rainfall-producers. The short-term model guidance indicates the potential for substantial rains (more than 1/2 inch) over the Suwannee Valley and areas east of Valdosta in South-Central Georgia through the evening hours as a subtropical disturbance moves over the peninsula. For the rest of our area, pockets of light to moderate rain lasting no more than 30 to 60 minutes at a time will move from southwest to northeast through midnight.
After midnight, we will watch the line of rain and storms approach from the west associated with the cold front and the main shortwave trough. The deep-layer wind fields are favorable for severe weather, but the amount of instability is still, even at this late hour, not agreed upon by the models. The GFS shows the most, but the NAM barely shows any at all. The multi-model ensemble mean (which basically takes an average of several different models) is forecasting any modest instability to be located south of I-10. Therefore, the highest threat for damaging winds and isolated tornadoes will be closer to the coast. The probabilities for severe weather decrease as one moves farther inland. At this time, we do not anticipate a widespread severe weather outbreak, but a couple of warnings could be issued. This storm will do us more good than harm since additional much-needed rain is expected.
The remaining rains will exit to the east Wednesday morning. A gradual decrease in cloud cover is anticipated during the afternoon, but temperatures will struggle to rise with an increasing northwesterly wind. The winds will die out Wednesday night leaving us in a position for ideal radiational cooling conditions. In fact, we expect a light freeze on Valentine's morning (now you have a good reason to cuddle with your significant other). After another cold start on Friday, temperatures will moderate back into the 70s from Friday afternoon through Sunday afternoon.
The global models continue to show the arrival of the next Pacific storm system this weekend. We continue to favor the bulk of this thing arriving Sunday afternoon and evening, as is indicated by the ECMWF, UKMET and finally the GFS model. However, we have noted that a weak/lead impulse could generate scattered showers on Saturday, but this is not yet agreed upon by the models. The GFS is most bullish with rains on Saturday, but our gut tells us the highest probabilities for rain will hold off until the second half of the weekend.