Daily Archives: December 21, 2014

Heavy Rainfall Potential through Wednesday; Slight Risk of Severe Storms Late Tuesday

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…Heavy Rainfall Potential through Wednesday…

…Slight Risk of Severe Thunderstorms NE Florida late Tuesday…

Synopsis & Timing

A very dynamic weather pattern will unfold over the southeast region over the next several days as a strong storm system develops across the central United States. Waves of moderate to locally heavy rainfall will impact the local area with embedded isolated thunderstorms beginning this afternoon, then a more widespread heavy rainfall event is expected Tuesday through Tuesday night ahead of a cold front. Strong to severe storms are possible across northeast Florida Tuesday afternoon through Tuesday Night. Widespread rainfall with embedded thunderstorms will impact the area Wednesday, with rainfall gradually ending west to east Wednesday night trailing a cold frontal passage. Cooler and drier conditions are expected by Thursday, Christmas day.

Impacts
The main local impact from this evolving storm system will be widespread heavy rainfall with storm totals nearing  3-4 inches across much of NE Florida, and 2-3 inches across SE Georgia. Locally higher amounts are likely especially over portions of the Suwannee River Valley. There is also the potential for isolated strong to severe thunderstorms, mainly Tuesday afternoon through Tuesday Night across Northeast Florida.
 
Rainfall:

At this time, widespread flooding is not a major concern given that it has almost been a month since significant rainfall fell across most locations. In addition, the rounds of heavy rain are expected during two distinct periods.  The first wave of moderate rainfall is expected later this afternoon through early Monday. Rainfall is expected to decrease in rate and coverage Monday afternoon through Monday night. The second wave of moderate to heavy rainfall is expected late Tuesday through Wednesday ahead of cold front.
Graphic1_21Dec2014

Storm Hazards:

At this time, the best window of opportunity for strong to severe storms is Tuesday afternoon through Tuesday night across northeast Florida. A few strong storms may impact southeast Georgia Tuesday Night, but instability will be more limited over this area. There will be a variety of strong to severe storms hazards including gusty winds of 40-60 mph, hail, and the potential for brief tornadoes, especially across the Suwannee River Valley Tuesday evening.  The threat for severe storms may shift into early Wednesday if forecast models continue to trend slower with the frontal passage.
Graphic2_Dec212014

This storm system is very dynamic and forecast models are in fair agreement through Monday morning, then begin to diverge with the timing of local impacts. Please continue to monitor this evolving weather pattern.

Additional Information Resources:
NWS Jacksonville Webpage:  weather.gov/jax
NWS Jacksoville Facebook:  facebook.com/US.NationalWeatherService.Jacksonville.gov
NWS Jacksonville Twitter:   twitter.com/NWSJacksonville
AHPS River Forecasts:  water.weather.gov/ahps2/index.php?wfo=jax