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Ed Mahmoud wrote:Haven't watched video yet, but was based on something Dr. Cahir taught him as un undergrad at Penn State, combination of low forecasted pressure and high forecasted wet bulbs.
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0329 AM CDT SAT MAY 17 2008
VALID 201200Z - 251200Z
...DISCUSSION...
GFS AND ECMWF IN SLIGHTLY BETTER AGREEMENT THIS FORECAST...THOUGH
LARGE DIFFERENCES CONTINUE TO EXIST BETWEEN THE TWO MODELS. BOTH
MODELS FORECAST SIGNIFICANT AMPLIFICATION OF THE UPPER PATTERN
THROUGH THE FORECAST PERIOD...WITH A LARGE TROUGH EVOLVING OVER THE
WEST AND A SECOND TROUGH PERSISTING ACROSS THE EAST...SEPARATED BY A
SHARP RIDGE.
THE ECMWF REMAINS MUCH MORE PERSISTENT WITH THE ERN FEATURE...AND
THUS MAINTAINS A RIDGE OVER THE CENTRAL U.S. BETWEEN TWO
HIGHLY-AMPLIFIED TROUGHS -- A CLASSIC OMEGA BLOCK.
MEANWHILE...THE GFS IS MUCH WEAKER WITH THE ERN TROUGH/UPPER
LOW...ALLOWING THIS FEATURE TO PROGRESS SLOWLY EWD INTO THE WRN
ATLANTIC. AS THIS OCCURS...THE CENTRAL U.S. RIDGE SHIFTS SLOWLY EWD
INTO THE ERN U.S. THROUGH THE END OF THE PERIOD...THUS FACILITATING
THE EVENTUAL DEAMPLIFICATION OF THE LARGE WRN U.S. TROUGH BY DAY 8.
WHILE BOTH MODELS DEPICT DEEP SLY FLOW ACROSS THE CENTRAL U.S.
THROUGH THE FIRST HALF OF THE PERIOD -- AND THUS A RETURN OF GULF
MOISTURE WHICH SUGGESTS AN INCREASE IN CONVECTIVE POTENTIAL WITH
TIME...TIMING AND LOCATION OF ANY SEVERE EVENTS REMAINS DIFFICULT TO
DISCERN AT THIS TIME. THUS...WILL NOT ATTEMPT TO OUTLOOK ANY THREAT
AREAS ATTM.
..GOSS.. 05/17/2008
DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0359 AM CDT MON MAY 19 2008
VALID 221200Z - 271200Z
...DISCUSSION...
GFS/ECMWF CONTINUE TO DEPICT A VERY HIGH AMPLITUDE/OMEGA-BLOCK-TYPE
PATTERN ACROSS THE CONUS THIS PERIOD...WITH A DEEP TROUGH TO LINGER
OVER THE WEST UPSTREAM OF A VERY STRONG RIDGE OVER THE CENTRAL U.S.
THROUGH AT LEAST DAY 5-6. WHILE UNCERTAINTY INCREASES WITH RESPECT
TO THE EVENTUAL BREAKDOWN OF THIS BLOCKING PATTERN -- WHICH COULD
BEGIN AS EARLY AS DAY 7 -- SEVERE POTENTIAL REMAINS APPARENT OVER
THE HIGH PLAINS DAYS 4-6.
A VERY WARM/MOIST BOUNDARY LAYER SHOULD BE IN PLACE BY DAY 4 ACROSS
THE PLAINS...THOUGH STRONG RIDGE -- AND THUS SUBSIDENCE/CAPPING --
SHOULD KEEP THE CONVECTIVE THREAT SUPPRESSED WWD NEAR A HIGH PLAINS
DRYLINE. HOWEVER...WITH FAVORABLE INSTABILITY AND AMPLE SHEAR
ANTICIPATED INVOF THIS BOUNDARY...A MULTIPLE DAY THREAT FOR SEVERE
STORMS IS EVIDENT. WHILE THE GFS CONTINUES TO SUGGEST THAT THE
THREAT WILL BE SOMEWHAT FURTHER E THAN THE ECMWF...BOTH AGREE THAT
THE GREATEST POTENTIAL SHOULD BE FOCUSED SOMEWHERE WITHIN A ROUGHLY
200 MILE-WIDE AREA CENTERED OVER THE HIGH PLAINS. THUS...WILL
MAINTAIN A THREAT AREA OVER PARTS OF THE NRN AND CENTRAL HIGH
PLAINS...AND EXPAND THE AREA SWD THIS FORECAST TO INCLUDE PARTS OF
NM AND W TX.
..GOSS.. 05/19/2008
Ed Mahmoud wrote:30 to 40 knot 850 mb jet per Euro, and some directional shear between 850 mb and 850 mb.
12Z WRF shows precip Oklahoma to South Dakota. Looking at AccuWx PPV site for WRF specifics, because Utah U site still fubar, 1000 J/Kg all the way to Nebraska, 2000 to 3500 Joules/Kg Kansas into Oklahoma, deep layer shear generally 40 to 60 knots. EHI bullesye Northwest Kansas.
The NIU Storm Machine forecast skew-T generator seems cranky today, no forecast skew-Ts for Dodge City or McCook, NE
CrazyC83 wrote:Ed Mahmoud wrote:30 to 40 knot 850 mb jet per Euro, and some directional shear between 850 mb and 850 mb.
12Z WRF shows precip Oklahoma to South Dakota. Looking at AccuWx PPV site for WRF specifics, because Utah U site still fubar, 1000 J/Kg all the way to Nebraska, 2000 to 3500 Joules/Kg Kansas into Oklahoma, deep layer shear generally 40 to 60 knots. EHI bullesye Northwest Kansas.
The NIU Storm Machine forecast skew-T generator seems cranky today, no forecast skew-Ts for Dodge City or McCook, NE
Shear of 40-60, is that significant enough for a tornado outbreak?
