U.S. Severe Weather Forecast
Mobile & Email Alerts Updated:
000 acus01 kwns 081946 swody1 Storm Prediction Center ac 081944 Day 1 convective outlook National Weather Service Storm Prediction Center Norman OK 0144 PM CST sun Dec 08 2013 Valid 082000z - 091200z ..no severe thunderstorm areas forecast... No changes to forecast reasoning or outlook from prior issuance. .Carbin.. 12/08/2013 Previous discussion... /issued 1013 am CST sun Dec 08 2013/ ... A strong jet core aloft will persist from the Southern Plains to the lower Great Lakes...immediately downstream from the large-scale trough over The Rockies and plains. At the surface...an Arctic front has been weakening slowly and is now drifting northward across the Continental shelf waters of the northern Gulf of Mexico. Elevated convection is ongoing within a belt of warm air advection above the frontal surface from la to the Tennessee Valley...which is being fed by a moisture plume emanating from the Bay of Campeche. 12z soundings show MUCAPE of 250-750 j/kg rooted near 850 mb...which will continue to support the risk for a few thunderstorms along the same corridor through the outlook period.
000 acus11 kwns 081930 sels mesoscale discussion Storm Prediction Center mesoscale discussion 081930 njz000-paz000-dez000-mdz000-dcz000-vaz000-wvz000-082130- Mesoscale discussion 2073 National Weather Service Storm Prediction Center Norman OK 0130 PM CST sun Dec 08 2013 Areas affected...northern Virginia...northern Maryland...northern del...southeastern PA and central and southern New Jersey Concerning...winter mixed precipitation Valid 081930z - 082130z Summary...moderate to heavy snow will persist from southeastern PA into extreme northern Maryland and central New Jersey this afternoon. Snowfall rates will locally exceed 1 inch per hour through 21z-22z. Farther south across northern Virginia and parts of central Maryland and del...the snow should begin to transition to periods of freezing rain by 21z. Discussion...a strip of moderate to heavy snow continues from southern PA...northern Virginia...northern Maryland through central New Jersey and is associated with an east-west frontogenetic zone in the 850-700 mb layer. This zone of stronger forcing will gradually shift northeastward with the heaviest snows moving offshore after by 22z. Some banded structures continue to be observed with rates from 1 to 2 inches per hour within the heavier snow bands. Farther south...the low level jet is developing northeastward in association with a east-northeastward ejecting shortwave trough. Warm advection above the near surface subfreezing layer should result in northward advance of the melting layer aloft and a transition from snow to freezing rain. The Theta-E advection has also contributed to a shallow unstable layer aloft...and freezing rain rates will be enhanced at times within the northeastward moving showers. .Dial.. 12/08/2013 ..please see www.Spc.NOAA.Gov for graphic product... Attention...WFO...phi...ctp...lwx... Latitude...Lon 39287477 38827609 38387859 39717780 40527678 40477514 40297388 39287477