NATIONAL WEATHER SERVICE TALLAHASSEE FL
441 AM EST Wed Jan 1 2014
NEAR TERM [Through Today]...
Current water vapor imagery shows upper level moisture streaming
northeastward from the eastern Pacific across the Gulf and into the
local area ahead of an approaching upper level trough.
Weak lift will support periods of rain across the area throughout the day.
Initially earlier this morning, rain had a tough time reaching the
ground due to a very dry layer around 3500 ft as seen on the 00z
KTAE sounding. However, this dry layer is already eroding quickly,
and rain is now reaching the ground across the northern and western
portions of the area. We expect this trend to continue through the
day with rain gradually becoming more widespread.
High temperatures will be held down by all the cloud cover and periods of rain, and the official forecast went on the lower side of the guidance envelope.
SHORT TERM [Tonight Through Friday]...
The fairly persistent and stubborn unsettled pattern is fcst to continue across the CWA for tonight and Thursday, with the elevated rain chances and expected total amounts of rainfall today, increasing further over the beginning of the short term period.
This will materialize as a weak disturbance over the northern Gulf of
Mexico gradually forms a weak Sfc Low which will track E-NE to the S
of our region. This low will help increase and energize the the
isentropic lift which is already ongoing.
When all is said and done, a widespread swath of storm total QPF between 1 and 2 inches of rain is expected, with locally higher amounts of 3 to perhaps even 4 inches falling in a few locations.
While this disturbance has been fairly sluggish to move off to the E-NE thus far, a very cold ridge of high pressure will certainly give it a speed boost off to the NE later on Thursday, with much colder and drier air advecting in from from the NW for Thursday night and Friday.
At this time, believe the bulk of the numerical guidance is forecasting low temperatures that are too cold for Thursday night given the strong pressure gradient and Sfc winds that are expected to stay strong through the night.
Therefore, have capped lows in the upper 20s to the NW to the lower
to mid 30s to the SE.
However, depending on how strong the winds actually remain through the night, Wind Chills could drop below 20 degrees for a decent sized portion of the CWA, and if this is the case, we could see our first Wind Chill Advisory of the season.
High temps on Friday will have little chance to recover as well, and
despite plenty of daytime insolation, they are not expected to get out of the upper 40s to the lower 50s, except for the extreme SE FL Big Bend where a few middle 50s may be observed.
LONG TERM [Friday Night Through Tuesday]...
The long term period features two separate cold air intrusions into the deep south.
At the start of the period, high pressure will be building down the Mississippi River Valley into Middle Tennessee on Friday morning.
As has been the case with most of the anticyclones this winter season, they have remained more to the north of the region and transited from the Tennessee Valley, to the Mid Atlantic, and then out to sea.
The result of this pattern is typically low temperatures several degrees above the longer range MEXMOS. This pattern continues once again in both the GFS and Euro on the 31/00z and 31/12z runs. As a result, think the low temperatures Friday night, while cool, will not be nearly as cold as once thought. Though a few spots may get into the upper 20s, most locations will likely remain around 30 to 33 degrees.
The pattern across the CONUS will remain quite fast throughout the
long term period, with only a brief period of quiet weather on
Saturday before the next system starts to develop across the Western
It is at this point on Sunday that the operational Euro and GFS diverge in their forecasts.
While confidence in this portion of the forecast is low, there are increasing signals that the operational Euro solution is the better choice for this part of the forecast.
The last three runs of the Euro analyzed for this forecast (30/12 through 31/12) were very consistent in the timing and development of a strong surface cyclone across the Eastern CONUS through Monday Evening.
While the operational GFS does not generate a robust cyclone, some development does occur across the Ohio Valley. And with several individual GFS ensemble members quite similar to the operational Euro solution, feel that it is only a matter of time before the operational GFS conforms to the solution presented by the Euro.
So, for our region, this could be the first significant Arctic outbreak of the season.
After a strong cold front moves through the region on Sunday, drastically colder air will surge in ahead of a strong high across the Northern Plains.
The reinforcing arctic front should arrive on Monday night.
This could result in high temperatures Monday and Tuesday struggling to reach 50.
Overnight temperatures could finally approach hard freezing levels (26 or less) by Tuesday morning as the Euro is indicating the potential of a more favorable track into the Deep South of the anticyclone.
VFR conditions are expected to prevail through most of the day, although light rain will gradually increase in coverage and intensity from southwest to northeast through the period.
Ceilings are expected to gradually lower to MVFR by this evening across the area, with IFR conditions possible by the end of the period at KECP and KDHN.
Generally light to moderate winds will continue over the coastal
waters today through the morning hours on Thursday, before a very
strong cold front tears quickly through the marine area from
northwest to southeast on Thursday afternoon.
The very potent cold and dry air rushing in over the still relatively mild northern Gulf of Mexico waters will create very strong Small Craft Advisory conditions in a short period of time, with the brunt of the effects felt on Thursday night, where conditions may need to be monitored for a possible Gale if frequent wind gusts over 34 knots occur.
Although strong, this Advisory is not expected to last very long as
winds and seas should taper off steadily during the day on Friday,
with a return back to cautionary levels possible by the afternoon or
Periods of rain are expected to overspread the area today and
Thursday with no fire weather concerns.
On Friday, drier air is expected to move into the area with minimum RH values approaching critical levels across portions of the inland Florida panhandle.
The Apalachicola River is above flood stage and is forecast to remain in minor flood stage through at least January 5th with releases from Woodruff Dam. The river is forecast to crest Tuesday at 19.2 feet near Blountstown.
The Choctawhatchee River is forecast to reach minor flood stage at Caryville and Bruce, and then crest Thursday at 12.5 feet near Caryville and Saturday at 13.5 feet near Bruce (depending on our final Storm Total QPF).
Other area rivers and creeks are elevated but remain below flood stage at this time.
Rainfall from the system Today through Thursday should average
between 1 to 2 inches across the region (with only isolated and
insignificant (in area) higher amounts possible).
This is not expected to be significant enough to cause any additional rivers to reach flood stage, though it may keep the Choctawhatchee River elevated for a couple more days.
PRELIMINARY POINT TEMPS/POP...
Tallahassee 58 50 67 32 50 / 70 80 90 20 0
Panama City 59 53 65 33 49 / 60 80 80 10 0
Dothan 56 46 61 29 49 / 60 90 80 10 0
Albany 57 46 62 29 49 / 60 90 80 10 0
Valdosta 58 49 67 32 50 / 70 90 90 20 0
Cross City 58 53 68 35 54 / 90 80 90 30 0
Apalachicola 58 54 66 33 48 / 80 80 90 20 0