Florida Weather

[AJC3]

I cannot believe our local Fox 35 tv Met is taking the NAM serious on its 84 hr forecast, not even the GFS is calling for freezing temps for central FL. He has posted on facebook that "the risk of a freeze Wednesday morning in Orlando is real", now everyone in this area panicking.

https://i.imgur.com/kUuOpXD.jpg

And of course, the extreme temps and WCIs of the NAM are largely predicated on a solution which shows a bombing 994MB low off the NEFL coast, a 16MB pressure drop in 12 hours. None of the other model SLP fields are close to being this low. #ThrowItOut

[northjaxpro]

I cannot believe our local Fox 35 tv Met is taking the NAM serious on its 84 hr forecast, not even the GFS is calling for freezing temps for central FL. He has posted on facebook that "the risk of a freeze Wednesday morning in Orlando is real", now everyone in this area panicking.

https://i.imgur.com/kUuOpXD.jpg

And of course, the extreme temps and WCIs of the NAM are largely predicated on a solution which shows a bombing 994MB low off the NEFL coast, a 16MB pressure drop in 12 hours. None of the other model SLP fields are close to being this low. #ThrowItOut

Yes indeed AJC3.

[gatorcane]

I agree the NAM looks unrealistic. But with the strong N to NNE winds Tues night, wind chills look to be an issue. So I think it could feel as cold as the NAM is showing if not colder in the 20s for parts of Central and North Florida. Even tonight and Monday night will feel quite cold.

[StormingB81]

Let’s all hope the NAM pans out and happens lol okay I had to be a little funny. I highly doubt that happens because all other models say other wise and not even close to that. Also lack of snow pack up north says I have a better chance at hitting the Powerball lol

[NDG]

I cannot believe our local Fox 35 tv Met is taking the NAM serious on its 84 hr forecast, not even the GFS is calling for freezing temps for central FL. He has posted on facebook that "the risk of a freeze Wednesday morning in Orlando is real", now everyone in this area panicking.

https://i.imgur.com/kUuOpXD.jpg

And of course, the extreme temps and WCIs of the NAM are largely predicated on a solution which shows a bombing 994MB low off the NEFL coast, a 16MB pressure drop in 12 hours. None of the other model SLP fields are close to being this low. #ThrowItOut

Apparently this Met at Fox 35 likes to show worst case scenario on FB a lot to create ratings, I just went back to his posts from earlier in the week and he’s been jumping from model to model or picking a particular run on whichever shows a freeze for our area and typing the same headline “the risk of a freeze...is real”

[AJC3]

I agree the NAM looks unrealistic. But with the strong N to NNE winds Tues night, wind chills look to be an issue. So I think it could feel as cold as the NAM is showing if not colder in the 20s for parts of Central and North Florida. Even tonight and Monday night will feel quite cold.

While WCI's in the lower 30s and upper 20s are nothing to sneeze at (figuratively, of course ), you may not realize just what it takes to get WCIs down into the upper teens at above freezing air temperatures.

At 35F, you need a sustained wind speed of 45 mph just to get a WCI of 19F.
At 34F, you need a sustained wind speed of 35 mph.
At 33F, you need almost 30 mph sustained.
Even at freezing, you still need a 20 mph sustained wind to drop the WCI below 20F.

For argument's sake, let's assume 15 MPH sustained winds TUE night, which is pretty close to the max that typically occurs here nocturnally during cold outbreaks.
The air temperature would have to get down to 30F to reach 19F.

IMO, for this event in central Florida (the MLB CWA), the only locations where the air temperature falls to at or below 35F will be sheltered locations where the wind drops off to around 5 MPH.
Some spots NW of I-4 may briefly see upper 20s WCIs, but I don't see the WCI's remotely approaching 20F.

Believe me when I say those numbers from the 00Z NAM are extreme outliers.

[NDG]

This is the reason why we will most likely not see a freeze from the I-4 corridor down south. During the night the winds will be switching to the NNE & NE at h925 around the low pressure area east the northern Bahamas, bringing in warmer temps and higher humidity in that level, and with NNW winds staying up at the surface some of the "warmer" more humid air will be mixing down to the surface, as long as the winds stay up at the surface.
This kind of set up is usually not the way we get our freezes, need those near calm winds and low humidity for a perfect radiational cooling. Not unless is a 1050 mb Arctic High with record low temps over the deep south.

[psyclone]

And my official low is now projected down to 38. That's plenty chilly for me. Time to make a giant pot of pasta and Netflix and hibernate for 3 days!

[AJC3]

The inexorable trip back to reality for the NAM has begun along the FL east coast. Freeze line is in white



Forecast temp at 12Z WED...
Melbourne:
19/00Z 31F
19/06Z 37F
19/12Z 40F



Orlando:
19/00Z 31F
19/06Z 31F
19/12Z 32F

I'd expect this trend to continue to spread farther inland over the next several model runs, albeit likely in a stairstep/uneven manner.

[NDG]

The inexorable trip back to reality for the NAM has begun along the FL east coast. Freeze line is in white

https://i.imgur.com/7IffCHx.png

Forecast temp at 12Z WED...
Melbourne:
19/00Z 31F
19/06Z 37F
19/12Z 40F

https://i.imgur.com/QiCKjNt.png

Orlando:
19/00Z 31F
19/06Z 31F
19/12Z 32F

I'd expect this trend to continue to spread farther inland over the next several model runs, albeit likely in a stairstep/uneven manner.

Yep, the temps should continue to go up as it starts joining the rest of the models with the strength and position of the low pressure area, typical, it did the same with weak tropical systems this past hurricane season all the time of over strengthening them.

[gatorcane]

I agree the NAM looks unrealistic. But with the strong N to NNE winds Tues night, wind chills look to be an issue. So I think it could feel as cold as the NAM is showing if not colder in the 20s for parts of Central and North Florida. Even tonight and Monday night will feel quite cold.

While WCI's in the lower 30s and upper 20s are nothing to sneeze at (figuratively, of course ), you may not realize just what it takes to get WCIs down into the upper teens at above freezing air temperatures.

At 35F, you need a sustained wind speed of 45 mph just to get a WCI of 19F.
At 34F, you need a sustained wind speed of 35 mph.
At 33F, you need almost 30 mph sustained.
Even at freezing, you still need a 20 mph sustained wind to drop the WCI below 20F.

For argument's sake, let's assume 15 MPH sustained winds TUE night, which is pretty close to the max that typically occurs here nocturnally during cold outbreaks.
The air temperature would have to get down to 30F to reach 19F.

IMO, for this event in central Florida (the MLB CWA), the only locations where the air temperature falls to at or below 35F will be sheltered locations where the wind drops off to around 5 MPH.
Some spots NW of I-4 may briefly see upper 20s WCIs, but I don't see the WCI's remotely approaching 20F.

Believe me when I say those numbers from the 00Z NAM are extreme outliers.

Thanks just to clarify, I mean the wind chills could feel like what the NAM actual low air temperatures are showing not the NAM wind chill values. I didn’t realize it took that much wind, thanks for the info.

[NDG]

By the way, Pivotal Weather is a fairly new site for models, consider donating to it to keep it free, is a lot easier to use than weather.us, with much better graphics. What's really cool is that a has a point and click feature on the Euro on sounding forecasts, something that tropical tidbits doesn't have on the Euro model.
Below is the link to sponsor, it still has a long ways to go to get its financial goal.

https://www.patreon.com/pivotalweather

[northjaxpro]

Excellent posts from you all today. AJC3 great analysis on the wind chill indices and NDG your analysis on the Low Pressure area off the coast and potential effects from I-4 corridor and points south.

You guys are pretty good and know your stuff! A pleasure knowing you both through the years on here and to call you fellow colleagues indeed in this business!

[SFLcane]

Only 6 gC at 2000 feet , 20 to 30 kts ! At Wednesday sunrise across SFL. I’d think windchills will definitely be a factor.

[northjaxpro]

Latest projection a bit colder for tomorrow morning at the NWS Jax office, now forecasting 35 degrees for tomorrow morning and interior areas around Lake City and the Suwannee River Valley may see an advection freeze tomorrow morming with temps forecast to fall into the 30-34 degree range in these areas in the morning. Wind chill indices could be as low as the mid-upper 20s in some locales across North Florida in the morning.

[gatorcane]

Looks like RGEM and WRF are colder by a few degrees than the GFS for Tuesday night, as far as those models go out. The cold-biases CMC which was warmer than the Euro and GFS yesterday (surprisingly) now has a freeze down into interior SW Florida for Wed night, the 00Z and 12Z runs are virtually identical. We may just see NWS notch the lows down a few more degrees when all is said and done. So far great job by the Euro in being consistent on mid 30s for Central Florida (upper 30s east to lower 40s east).

[NDG]

12z Euro is almost identical to last night's run, persistent in low temps in the mid 30s along the I-4 corridor, and is also persistent in low temps in the low 40s in SE FL, while the GFS is 10 degrees warmer for SE FL.
The strength and position of the low pressure will make a bid difference of how much cold air is able to wrap around it down the spine of the peninsula, I think the Euro's solution is a good solution to go by for now between the models that are in both extremes.

[psyclone]

My NWS forecast lows the next 4 nights: 50, 41, 38, 50.
And that's the most this winter has been able to muster thus far

[TheStormExpert]

Hard to believe it snowed all throughout South Florida on this day back in 1977! Times and weather patterns have surely changed since then. Wonder if we’ll ever see such a rare event ever again?

 https://twitter.com/nwsmiami/status/1218881807791411201

[northjaxpro]

Temps fairly uniformed across North Florida this morning and it appears that there are no reporting observations reporting at or below freezing temperatures. Lake City and Crestview, out in the panhandle, are the coldest I can see at 7 a.m., with 34F. Most everywhere across the North Florida region is in the mid-upper 30s this hour, except along areas of the St. Johns River and the coast where readings in those areas are generally in the upper 30s to lower 40s currently. It is 36.4 degrees currently at my home station. Cold wind chills and brisk NW wind this morning across the region.

Strong cold air advection will continue through Wednesday. 500 mb heights really amplify sharply at the base of the upper trough along and.just off the Southeast U.S. Atlantic coast as a rather significant Low Pressure system develops just northeast of the NW Bahamas. Strong 1045 mb Polar High currently dropping down from the Northern Plains and will be approaching the TN Valley region by early Wednesday. This will strengthen the cold air advection with NNW flow deep into the peninsula on the backside of the Low Pressure area, especially Tuesday through into Wednesday morning. Expecting light freeze across the area tomorrow morning with 31 degrees forecast for my area, but upper 20s interior Northeast Florida definitely possible. Wednesday morning could be the coldest of the season to this juncture. Winds are forecast to lay down and promote more radiational cooling potential on Wednesday morning. Hard Freeze may occur over the Suwannee River Valley and Big Bend areas on Wednesday morning as temps may drop in those areas into the mid-upper 20s.
Temps are forecast to drop into the upper 20s to near 30 at my locale outside of Jax International Airport on Wednesday morning and areas in Western Duval County and out to the U.S. Hwy 301 corridor.