Well, HPC surface analysis shows a 1044 mb Arctic High centered over Nebraska as of 14Z. This High has turned out to be a bit stronger than initially analyzed by the models 48 hours ago. This helps to explain the colder trends the past couple of days.

Winds picking up now as the pressure gradient with the building High Pressure from the Plains and the departing Low pressure area off the mid-Atlantic . A very good advective freeze event for tonight setting up across North Florida as hard freeze warnings are now in effect across this region.

NWS projected lows tomorrow morning:

Pensacola 25
Panama City 29
Tallahassee 24
Appalachicola 28
Jacksonville 27
Gainesville 26


Central Florida

Tampa 35
Orlando 36
Daytona Beach 34


For now, it appears that the freeze line will drop to near Brooksville -Leesburg - Flagler county observing the latest model runs. Hopefully, the freeze line won't drop a bit farther south to the I-4 corridor by tomorrow, but it is going to be a closer call down there than was initially expected 48 hours ago that's for sure.

i think the central florida ag regions will come through this just fine. and mid 20's in north florida in mid feb is to be expected. it's just a bit of a shocker since we've been so spoiled as of late. and, like the other cold snaps this winter, we're going to v notch right out of it and be basking in warmth a few days later. i think the latest freeze recorded at TPA is march 5 so time is quickly running out for freezes in central florida.

Well, the freeze line may actually get as far south as the I-4 corridor afterall....


NWS has now issued Freeze warnings for Hillsborough, Polk, Osceola, Lake, Orange, Seminole and Volusia counties for early tomorrow morning. Freeze watches are in place for these same areas for early Monday morning as well.

Also, NWS Jax office has now upgraded Marion county to hard freeze warning for Sunday morning.

Hard Freeze watches are in effect for all of North Florida for early Monday morning.

They are anticipating a reinforcement of cold air around 4am here. However, if that is accompanied by continued wind, my coastal area will be fine as the waters are 68F. It is MOnday morning's calm winds that concern me. After all this warmth, this could really injure plants. Oh well, I was anticipating a piece of arctic air coming in. Then, its warmth back again.

Yeah, it has been a classic La Nina season that's for sure. Long periods of unseasonable warmth, with only a few quick shots of modified arctic air coming in for only a couple of days. This particular cold spell is the first we have seen come into our region since the first week of January 2012.

Held good until.. the winds turned north after midnight. It is now 33.1F with a stiff wind. Despite high cloud deck, it is almost freezing and Friday was 79F and rather humid. I couldn't even guess at the wind chill. This is going to be a long, cold day and an even longer night. My yard may not be pretty with this kind of quick turn around, and wind chill. My shadehouses will have to be covered in frost cloth to make it tonight. Figures! Everything was just beginning to come around in growth.

Well, my thinking of temps staying above freezing along the I-4 corridor busted, lol. So did the forecasted lows for the Orlando area by the NWS office. This is one time that the MOS forecasted lows actually came through.
This is one heck of an Arctic High, the winds were whipping yesterday afternoon. Had there been more snow across the plains and some snow cover across the deep south this would had been a catastrophic freeze for central FL's citrus growing areas.
As far as tonight, the good news is that the 06z GFS MOS guidance has actually gone up 1 degree from its 0z run, so at least we are not seeing a continuing trending down by guidance.
It is showing low to mid 30s along the I-4 corridor. Low 30s for the rural areas, mid 30s for metro areas. Areas along and west of I-75 north of Tampa is showing temps even colder for tonight, with low 20s from Brooksville on northward.

It got down to 24.3 degrees at my home location in north Jacksonville this morning. I just checked and it was also 24 degrees at the NWS office at the International Airport, which set a new record low temperature on this date.

This arctic air mass is very impressive indeed. Cold advection continues today as the massive 1040 mb arctic High centered over Missouri early morning will move in closer toward the SEUS throughout the day. By tonight, the arctic high will move closer to allow the winds to slacken. The wind should become light enough to allow for decent radiational cooling by Monday morning. High temps today will only reach the upper 40s to near 50 in Jax metro today.

Hard freeze warning again tonight for all of North Florida and freeze watches are still up for the counties along the I-4 corridor for Monday morning. I suspect that may get upgraded to freeze warnings down there later today.

The warm-up will begin on Tuesday as the upper level trough shifts east into the Western Atlantic and the upper level flow becomes nearly zonal. So enjoy this cold spell while its here.

It hit 33.1F here, and dropped about 12 degrees in 4 hours prior to dawn. The winds turned N/NE and I lost the effect of the water. Tonight will be bad, and after all this warmth!

It's 36.2 degrees on my thermometer at 11 a.m. High temps today will only struggle just to make the upper 40s at best here.

NWS Jax calling for 25 degrees tomorrow morning. Also, this is only the eight day of temps at or below freezing measured here for this season and will certainly add another day tomorrow.

For those of us in South Florida, this is also nothing short of impressive. Here at my home in western Broward county, north of 595 by the glades, it's still 47 degs at noon. if we get clear skies just in time for sundown, this might spell some trouble for parts of interior south Florida.

Clouds could save S FL tonight even interior areas with winds turning onshore at H925.

Here is the 12z GFS MOS guidance for tomorrow morning:

West Palm 45
Ft Lauderdale 47
Homestead 45
Miami 49
Naples 40
Ft Myers 38
Daytona Beach 31
Brooksville 21
Gainesville 21
Ocala 22
Leesburg 30
Orlando Int'l 34
Orlando Exec Airport 36
Orlando-Sanfort Airport 32
Tallahassee 20
Tampa Int'l 33
St Pete Int'l 36
St Pete Whitted Field 41
Jacksonville Int'l 22
Jacksonville NAS 30
St Augustine 27

Thanks NDG for providing the GFS MOS guidance numbers. The MOS numbers from last night sure came very close to verifying in most places. MOS called for 23 degrees at NWS Jax yesterday and the actual low was 24, which set a new record low for this date. MOS now calling for 22 degrees at NWS Jax office tomorrow morning, but I believe the actual temperature may go even slightly lower than that.

Right now, the current dew point temperature at is 2 degrees at the NWS office. Tonight, the winds will become light and with clear skies and a super dry modified arctic air mass in place, the mercury is really going to bottom out by sunrise tomorrow morning. I think it is very possible we will see more record low temps at several locations tomorrow morning.

without question this is a pretty impressive cold shot, certainly more so than i expected a few days ago. temps are struggling to reach 50 in central florida in the afternoon despite bright sun...and dewpoints are in the teens.

Good news for at least the immediate eastern coast of FL from the Daytona area on southward, as the winds have turned from a NW direction from earlier this morning to a more northerly to even NNE wind in some places the dewpoints have come up from the teens to the 20s and 30s.

Just checked the record analog and although we will have another very cold night , I found that it is not likely we will break a record at NWS Jax office. There was a record cold spell that occurred in Florida on the heels of the Great Southern U.S. Blizzard during Feb 12-13 1899. Tallahassee's all-time record of -2° F was set on February 13, 1899. This also remains the coldest temperature ever recorded in the state's history. The record low for tomorrow for Jacksonville is 10 degrees, also set back in 1899 during that event..

Quick cold shot and 80 by tuesday.

Mid level clouds moving in from the northern gulf coast into the FL P could be a saving grace for parts of central FL if they are able to make it in without evaporating.
http://www.ssd.noaa.gov/goes/east/gmex/flash-avn.html

0z NAM does not show much if any cloud cover in the morning in central and northern FL, but it was started not seeing the current cloud cover the northern gulf coast.

Already down to 27.2 degrees at my location at this hour. It sure does look like we are going to get even colder than last night's readings here in this area. I think spots will get down right at 20 degrees by sunrise, and I would not be surprised if I see a 18 or 19 degree reading in the usual cold drainage spots across the region.

NDG, I don't think those clouds you referenced in your above post will make it into the North Florida area. This air mass is just too dry for any clouds to make it in this region. But, as you stated, it may help to save portions of Central Florida from experiencing a significant freeze. Dew point readings in the central Florida region at this hour has come up into the upper 20s and lower 30s, compared to only mid teens for dew point readings in my region currently. So, there is a slight chance those clouds could drift over parts of the central peninsula since the moisture content has slightly increased during the evening over that part of the state. We will know how this pans out when we get up in the morning.

52 right now. Forecast temps of 49-50 seem reasonable with winds turning more onshore and high clouds.

Was watching those high cirrus clouds earlier....they were really streaming across the sky. When you can see their movement that obviously, you know they are booking it.