May 23rd ish - Severe Threat? - UPDATED

UPDATE - SUNDAY MORNING

Should have stuck to my gut...here is the SPC with their thoughts.

ZCZC SPCSWOD48 ALL ACUS48 KWNS 180837 SPC AC 180837 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0337 AM CDT SUN MAY 18 2008 VALID 211200Z - 261200Z ...DISCUSSION... EXTENDED MODELS -- THOUGH THEY CONTINUE TO DIFFER SOMEWHAT WITH RESPECT TO THE UPPER PATTERN EVOLUTION...PARTICULARLY LATE IN THE PERIOD -- PERSIST IN SUGGESTING A GENERAL INCREASE IN SEVERE POTENTIAL OVER THE CENTRAL CONUS DURING THE LATTER HALF OF THE UPCOMING WEEK. BOTH DEVELOP A LARGE TROUGH OVER THE WRN U.S. AND SUBSTANTIAL NWD RETURN OF RICH GULF MOISTURE INTO THE PLAINS STARTING DAY 4. WHILE SOMEWHAT MERIDIONAL...FLOW ALOFT SHOULD REMAIN STRONG ACROSS THIS REGION -- AND THEREFORE EXPECT BOTH THE KINEMATIC AND THERMODYNAMIC ENVIRONMENT TO BE SUPPORTIVE OF SEVERE STORMS. DIFFICULTY PERSISTS...HOWEVER...IN NARROWING DOWN THE REGION OF GREATER THREAT -- BOTH SPATIALLY AND TEMPORALLY -- DUE TO MODEL DIFFERENCES. ATTM...GREATEST POTENTIAL APPEARS TO EXIST DAYS 5-7 /I.E. THU. MAY 22 THROUGH SAT. MAY 24/ ACROSS PARTS OF THE CENTRAL AND NRN PLAINS. THE GFS -- WHICH DEPICTS THE UPPER RIDGE FARTHER E THAN THE ECMWF -- WOULD APPEAR TO FAVOR CENTRAL KS/CENTRAL NEB ALONG ERN FRINGES OF A FAIRLY WELL-DEVELOPED SURFACE LOW. MEANWHILE...THE ECMWF WOULD FAVOR A PRIMARY THREAT AREA FURTHER WWD -- ACROSS THE CENTRAL AND NRN HIGH PLAINS -- WITHIN SELY UPSLOPE FLOW REGIME E OF A SHARPER LEE TROUGH/LOW. ATTM...WILL INTRODUCE A THREAT AREA FOR DAYS 5-7 ACROSS MUCH OF KS/NEB AND INTO PARTS OF ERN CO/ERN WY -- COVERING PORTIONS OF THE ENVELOPE ENCLOSING SOLUTIONS FROM BOTH MODELS.

END UPDATE

UPDATE - SATURDAY EVENING

The GFS has the vorticity cutting off and never getting here. Stay tuned..the energy will have to eject somewhere/sometime..just not on next Thurs.

LOL

END UPDATE

UPDATE - SATURDAY

Models are shifting quite a bit now. Timing is up in the air and the upper air support seems to be lagging. Lets keep watching into Monday/Tues to see what is really there. I would believe based on the trends we would be seeing a cold front with some moisture return in place and convective potential. Will take a look tomorrow/Monday.

END UPDATE

UPDATE - The SPC is beginning to hint at this time period...

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0353 AM CDT FRI MAY 16 2008



VALID 191200Z - 241200Z



...DISCUSSION...

SEVERE POTENTIAL SHOULD REMAIN RELATIVELY LOW DAYS 4 AND 5...WITH A

LARGE MEAN TROUGH REMAINING OVER THE ERN HALF OF THE CONUS.



FROM DAY 6 ONWARD...BOTH THE GFS AND ECMWF SUGGEST A RETURN TO A

MORE ACTIVE SEVERE WEATHER PATTERN...AS BOTH BEGIN TO PROGRESS THE

ERN TROUGH EWD.  HOWEVER...THE MODELS DIFFER GREATLY IN THE DETAILS

OF THE PATTERN EVOLUTION...WITH THE GFS MUCH MORE PROGRESSIVE WITH

THE ERN FEATURE -- WHILE A SECOND TROUGH DEEPENS ACROSS THE CENTRAL

CONUS.



MEANWHILE...THE ERN TROUGH IS FORECAST BY THE ECMWF TO LINGER OVER

THE CANADIAN MARITIMES/NEW ENGLAND...AND THUS THE UPSTREAM TROUGH

REMAINS OVER THE ROCKIES THROUGH THE END OF THIS FORECAST PERIOD.



THEREFORE -- WHILE BOTH MODELS WOULD SUGGEST INCREASING SEVERE

POTENTIAL DURING THE SECOND HALF OF THE PERIOD...DRASTIC MODEL

DIFFERENCES PRECLUDE HIGHLIGHTING ANY SEVERE AREAS THIS FORECAST.

END UPDATE


Must be a Tues/Thursday thing. Seems like each main event lately has fallen on one of these days. Other than one Saturday, seems like things just happen on the other two days. Maybe its just me...



So, here we go again for next week. First I want to point out the similarities in the upper air to the last cycle 52-54 days ago...you know..this years cycle...LOL



Here is March 30th


.

Here is what is coming up for May 22/23rd



Notice the vorticity central Canada that cuts off due to the strong ridging to its east. Same as in March. Notice the strong flow coming into it from the big ridging in the Pacific NW?



Same picture.



So, lets get to the specifics. I took the surface map for the 22nd and drew the features...



We get into the SE quad of this cold front as it moves in. We will have to watch this as it gets closer for more defintion. I believe this is something to be watched.



For those curious about what happened 54ish days back..here is the link to the SPC for the events that day...

http://w1.spc.woc.noaa.gov/exper/archive/events/080330/index.html



Here is the forecast sounding for this day upcoming...



http://weather.admin.niu.edu/chaser/tempgif/14296.TXT



Lets keep an eye on it. The NWS is hinting at it, but somewhat dismissive due to cap potential.

We will have to see how it pans out.