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| Day 4-8 Severe Weather Outlook Issued on Jan 26, 2013 |
| Updated: Sat Jan 26 09:26:02 UTC 2013 |
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| D4 | Tue, Jan 29, 2013 - Wed, Jan 30, 2013 |
D7 | Fri, Feb 01, 2013 - Sat, Feb 02, 2013 |
| D5 | Wed, Jan 30, 2013 - Thu, Jan 31, 2013 |
D8 | Sat, Feb 02, 2013 - Sun, Feb 03, 2013 |
| D6 | Thu, Jan 31, 2013 - Fri, Feb 01, 2013 |
(All days are valid from 12 UTC - 12 UTC the following day) |
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Note: A severe weather area depicted in the Day 4-8 period indicates a 30% or higher probability for severe thunderstorms within 25 miles of any point.
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PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
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POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears highly unlikely during the entire period (e.g. less than a 30% probability for a regional severe storm area across the CONUS through the entire Day 4-8 period).
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ZCZC SPCSWOD48 ALL
ACUS48 KWNS 260925
SPC AC 260925
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0325 AM CST SAT JAN 26 2013
VALID 291200Z - 031200Z
...DISCUSSION...
LATEST SUITE OF MODEL GUIDANCE PRESENTS A BETTER GENERAL CONSENSUS
IN THE FORECAST EVOLUTION OF THE LARGE SCALE PATTERN ACROSS THE
CONUS INTO THE MIDDLE OF NEXT WEEK...ESPECIALLY WHEN COMPARED TO
THIS TIME YESTERDAY. WHILE THERE REMAIN DIFFERENCES IN THE
CONFIGURATIONS AND MAGNITUDES OF THE VARIOUS FLOW FIELDS AND
PARAMETERS...ANALYSIS OF THE GFS/ECMWF/UKMET/CMC/GFS ENSEMBLE AND
DPROG/DT LOOPS LEND SUFFICIENT SUPPORT FOR THE REINTRODUCTION OF A
SEVERE WEATHER FORECAST...NOW VALID FOR D4/TUESDAY...WITH A
CONTINUING THREAT INTO AT LEAST PART OF D5/WEDNESDAY.
AS INDICATED IN THE D3 OTLK...A WARM MOIST BOUNDARY LAYER IS
EXPECTED TO RESIDE ACROSS THE SCNTRL U.S. AHEAD OF A STRENGTHENING
LARGE SCALE TROUGH AND ASSOCIATED DEVELOPING COLD FRONT. WHILE ECMWF
CONTINUES TO FORECAST A SLIGHTLY SLOWER AND LESS FULLY-PHASED UPPER
TROUGH WHEN COMPARED WITH GFS/UKMET MODELS...EVEN IT COMES AROUND TO
FORECASTING AN AMPLIFIED AND SUBSTANTIALLY PHASED LARGE SCALE UPPER
TROUGH ACROSS THE SCNTRL AND ERN U.S. BEGINNING D4/TUESDAY AND
CONTINUING THROUGH D5/WEDNESDAY. THIS PROCESS WILL CONTRIBUTE TO A
RAPID ONSET OF DEEP-LAYER ASCENT AND SUBSEQUENT TSTM DEVELOPMENT
ALONG AND AHEAD OF A SHARPENING COLD FRONT THAT WILL SWEEP EWD/SEWD
ACROSS THE CNTRL/SRN PLAINS DURING THE DAY TUESDAY...AND THEN TO THE
TN VALLEY/NRN GULF COAST AND SOUTHEAST THROUGH WEDNESDAY. SHEAR AND
INSTABILITY AS CURRENTLY FORECAST WILL PROMOTE ORGANIZED STORMS IN
EITHER SUPERCELL OR LINEAR FORMS FROM NORTHEAST TX ACROSS THE
ARKLATEX TO SERN MO/WRN TN. SQUALL LINE OR LINE SEGMENT EVOLUTION
SHOULD BECOME MORE LIKELY WITH TIME AS COLD FRONT/CONVECTIVE COLD
POOLS FURTHER INTENSIFY AMIDST MODEST INSTABILITY. DAMAGING
WINDS...POSSIBLY WIDESPREAD...WILL BE THE GREATEST HAZARD WITH THIS
CONVECTION. HOWEVER...LOW LEVEL SHEAR WILL BE STRONG ENOUGH FOR
TORNADOES AS WELL.
EXPECT THE STRONG FORCING AND SHEAR TO MAINTAIN A QLSC WITH DAMAGING
WIND POTENTIAL AT LEAST INTO THE TN VALLEY THROUGH EARLY
WEDNESDAY/D5. BEYOND THIS TIME...GREATER MODEL SPREAD AND RESULTING
UNCERTAINTY BEGIN TO IMPACT FORECAST CONFIDENCE IN SEVERE WEATHER.
HAVE OPTED TO RELY ON GFS ENSEMBLE JOINT PROBABILITY FORECASTS FOR
INSTABILITY AND SHEAR THROUGH LATE WEDNESDAY. THESE PRODUCTS SUGGEST
THAT SEVERE WEATHER POTENTIAL WILL BE MUCH MORE UNCERTAIN WITH EWD
EXTENT DESPITE STRONG QPF AND UVV SIGNALS ALONG THE ADVANCING FRONT
TO THE EAST COAST. PORTIONS OF THE SOUTHEAST MAY BE ADDED IN LATER
OUTLOOKS IF MODEL CONSENSUS IMPROVES.
..CARBIN.. 01/26/2013
CLICK TO GET WUUS48 PTSD48 PRODUCT
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