May 1st-2nd Storm

Ok...I know that this has been posted on the other two forums, but didn't want y'all to think that I was ignoring the site.

St. Louis (LSX) AFD...

WEATHER WILL BE TRANQUIL MID WEEK AS AN UPPER ZONAL FLOW IS FORECAST
BY THE GFS AND ECMWF ACROSS THE AREA. BY THURSDAY MORNING, BOTH
MODELS FORECAST A DEEP TROUGH/CLOSED LOW TO DIG INTO THE SOUTHERN
ROCKIES. THE SURFACE LOW THAT DEVELOPS AS A RESULT LOOKS MORE LIKE
EARLY MARCH THAN EARLY MAY.

Lincoln (ILX) AFD...

LONG TERM...WEDNESDAY THROUGH SATURDAY...
STRONG WARM ADVECTION WILL COMMENCE ACROSS THE MID SECTION OF THE
NATION WEDNESDAY AND THURSDAY AHEAD OF ANOTHER DEEP UPPER TROUGH
THAT WILL MOVE INTO THE ROCKIES AND EVENTUALLY INTO THE PLAINS. LEE
TROUGHING/CYCLOGENESIS WILL TAKE PLACE OVER THE LEE OF THE MOUNTAINS
AND PROVIDE DEEP SOUTHWESTERLY FLOW...BUT IT WILL TAKE A COUPLE OF
DAYS FOR ENOUGH MOISTURE TO MAKE IT BACK INTO THE MIDWEST AFTER
BEING SHOVED SO FAR SOUTH INTO THE GULF BY THE EARLY-WEEK SYSTEM.
THE GFS AND ECMWF HAVE BEEN FORECASTING WARM FRONTAL DEVELOPMENT
SOUTH OF ILLINOIS AND PUSHING THIS FEATURE NORTH INTO THE REGION
THURSDAY. BY THAT TIME...THE WESTERN TROUGH IS FORECAST TO EMERGE
INTO THE PLAINS AND DRIVE THE NEXT LOW PRESSURE SYSTEM INTO THE
MISSISSIPPI VALLEY AROUND FRIDAY. MODEL DIFFERENCES STILL EXIST ON
THE EXACT EVOLUTION OF THE UPPER TROUGH AND TRACK OF THE ASSOCIATED
SURFACE LOW...SO NOTHING MORE THAN CHANCE POPS ARE WARRANTED FOR NOW
BASED ON LOW PREDICTABILITY. HOWEVER IT IS NOTABLE THAT NUMERICAL
GUIDANCE BASED ON THE GFS MODEL...WHICH HAS A SIGNIFICANT WEIGHT
TOWARD CLIMATOLOGY BY DAYS 6 AND 7...HAS POPS THAT ARE TWICE AS HIGH
AS CLIMATOLOGY ON FRIDAY.

cant wait for this one but as usual it depends on a lot!
however, LIs are way negative, CAPE looks good, Cinh is eroding fast, time of day is looking favorable

Gotta wait and see, looks like the targe area for Thursday will be the plains. As for Friday, its a bit unclear but threat will push east.

Updated SPC Outlook...



DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0342 AM CDT MON APR 28 2008

VALID 011200Z - 061200Z

...DISCUSSION...
MAJOR MID/UPPER LEVEL LOW -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY
FROM GULF OF AK SWD ALONG 140W TO NEAR 40N -- IS FCST TO MIGRATE
SEWD OVER NWRN CONUS AND SWRN CANADA THROUGH DAY-3...THEN REDEVELOP
SEWD ACROSS CENTRAL PLAINS DAYS 4-5/1ST-3RD. BEGINNING ABOUT MIDDLE
OF DAY-4...OR 02/00Z...CONSIDERABLE SPREAD BEGINS TO APPEAR BETWEEN
OPERATIONAL MODELS AS SHORTWAVE DETAILS MORE STRONGLY IMPACT
GEOMETRY OF SYSTEM AND SUBSEQUENT EVOLUTION. MREF GUIDANCE IS
UNAVAILABLE...HOWEVER...STG CONSENSUS IS TAKING SHAPE AMONGST
DETERMINISTIC ECMWF/SPECTRAL/UK PROGS REGARDING BASIC DAY-4 PATTERN
-- STG MID/UPPER VORTEX ALOFT...DEEPENING THEN OCCLUDING SFC CYCLONE
MOVING ACROSS PORTIONS NRN KS/ERN NEB...TRAILING COLD FRONT MOVING
SEWD OVER SRN HIGH PLAINS...AND DRYLINE SSWWD FROM LOW ACROSS
PORTIONS CENTRAL/ERN KS...CENTRAL OK...AND N-CENTRAL OR NW TX.
RETURN FLOW MOISTURE MAY BE SUFFICIENT TO SUPPORT WIDESPREAD SVR
POTENTIAL FROM NEAR AND E OF SFC LOW SWD TOWARD ARKLATEX/SE OK
REGION. DEEP-LAYER LOW IS FCST TO OCCLUDE DEEPLY AND BEGIN FILLING
DAY-5/2ND-3RD...WITH TOO MUCH PROG SPREAD FROM THEN ONWARD TO ASSIGN
ADDITIONAL SVR-DAY AREAS.

Frank Straight just explained in his 7:45 pm Sunday blog one theory of why the UK and Euro models are slower than the GFS. There is a blocking situation over the Atlantic with a high pressure to the north of the low, which slows things down in the US. He states that the GFS usually doesn't realize how strong the blocking is going to be.

Watch it here.

Looks like a 2 day out break (Thursday/Friday), though there are a lot of factors that still need to be worked out.

Day 2 Outlook...



DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0231 AM CDT TUE APR 29 2008

VALID 011200Z - 021200Z

...THERE IS A SLGT RISK OF SVR TSTMS ERN NEB/WRN IA SSWWD TO
PORTIONS N-CENTRAL/NE TX...

...SYNOPSIS...
BROAD MID/UPPER CYCLONE NOW OFFSHORE PACIFIC NW AND BC WILL SHIFT
ESEWD ACROSS PACIFIC NW AND OVER MUCH OF CENTRAL/NRN ROCKIES BY
1/12Z. LEAD SHORTWAVE TROUGH NOW OFFSHORE ORE SHOULD EJECT NWD
ACROSS MT DAY-2 AND REINFORCE/MERGE WITH CYCLONE CORE OVER SRN AB BY
START OF THIS PERIOD. MEANWHILE...VORTICITY LOBE -- NOW EVIDENT IN
MOISTURE CHANNEL IMAGERY OVER GULF OF AK...IS FCST TO REVOLVE SWD
THEN SEWD AROUND UPPER CYCLONE AND AMPLIFY CONSIDERABLY...REACHING
CENTRAL ROCKIES OR CENTRAL HIGH PLAINS BY 2/00Z. MODEL
INCONSISTENCIES DESCRIBED IN DAY-2 OUTLOOK WITH THIS SHORTWAVE
TROUGH...AND WITH LOCATION OF ASSOCIATED SFC CYCLONE ALONG COLD
FRONT...EXTEND INTO DAY-3 PERIOD...AND WILL AFFECT LOCATION/STRENGTH
OF GREATEST SVR POTENTIAL.

PRIND SFC LOW SHOULD LIFT NEWD ACROSS CENTRAL/N-CENTRAL KS EARLY IN
PERIOD AND BE LOCATED SOMEWHERE OVER ERN NEB BY 2/00Z...WITH COLD
FRONT TRAILING SWWD ACROSS S-CENTRAL/SERN KS...N-CENTRAL THROUGH
W-CENTRAL/SW OK AND TX PANHANDLE. DRYLINE SHOULD INTERSECT FRONT
INVOF N-CENTRAL OK AND EXTEND SSWWD ACROSS PARTS OF CENTRAL/SRN OK
AND N-CENTRAL/NW TX. COLD FRONT SHOULD OVERTAKE DRYLINE OVERNIGHT
AND MOVE EWD INTO MO...AND SEWD ACROSS ERN OK AND WRN/NRN TX.

...CENTRAL/SRN PLAINS...LOWER MO VALLEY...
SOMEWHAT TIGHTLY CLUSTERED SVR OUTBREAK IS POSSIBLE -- INCLUDING
SUPERCELLS WITH LARGE/DAMAGING HAIL AND POSSIBLY SIGNIFICANT
TORNADOES. ATTM...CONSENSUS OF SREF AND OPERATIONAL PROGS INDICATES
PORTIONS ERN KS...NERN OK...AND WRN MO MAY HAVE MAXIMUM OVERALL
POTENTIAL. HOWEVER...NON-TRIVIAL THREAT EXTENDS NWD TOWARD SERN
NEB/SRN IA/NRN MO AND SWD OVER ERN OK/NWRN AR. UNCERTAINTIES
PRECLUDING GREATER PROBABILITIES ATTM INVOLVE TRACK/INTENSITY OF SFC
LOW AND RELATED LOW LEVEL FORCING...NWD EXTENT OF MOST FAVORABLE
RETURN FLOW MOISTURE...AND CAPPING ALONG/AHEAD OF DRYLINE OVER ERN
OK AND RED RIVER REGION. AS SOME OF THESE MESOSCALE DETAILS BECOME
BETTER RESOLVED...CATEGORICAL RISK UPGRADE IS POSSIBLE FOR THIS FCST
PERIOD.

STRONGER DEEP-LAYER FORCING IS FCST TO LIFT NEWD ACROSS LOWER MO
VALLEY REGION DURING DAY...WITH EARLIER INITIATION OF STG-SVR TSTMS
LIKELY THAN FARTHER S WHERE SBCINH WILL BE STRONGER AND LOW LEVEL
CONVERGENCE SOMEWHAT WEAKER. NRN PORTION OUTLOOK INCLUDES
CONDITIONAL POTENTIAL OF RELATIVELY SMALL/LOW-TOPPED SUPERCELLS WITH
TORNADOES AND HAIL JUST NE-E OF SFC LOW. FARTHER S...LARGE
LOW-MIDLEVEL LAPSE RATES...STRONGER CAPPING...GREATER LOW LEVEL
MOISTURE AND STRONGER HEATING WILL CONTRIBUTE TO SOMEWHAT MAXIMIZED
POTENTIAL FOR DISCRETE....WIDELY SCATTERED TO ISOLATED DEVELOPMENT
OF SUPERCELLS WITH POTENTIAL FOR SIGNIFICANT SEVERE OVER ERN OK AND
SERN KS. DEVELOPMENT FARTHER S TOWARD N-CENTRAL TX BECOMES
PROGRESSIVELY MORE CONDITIONAL...ESPECIALLY BEFORE DARK. BAND OF
SVR TSTMS SHOULD EVOLVE BY AROUND 02/06Z FROM MO SWWD ACROSS ERN
OK/WRN AR AND PERHAPS NE TX...WITH THREAT EVOLVING MORE TOWARD
DAMAGING WIND...BUT WITH TORNADOES AND HAIL STILL POSSIBLE.