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Day 33 Discussion


Paul Sherman

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Posted
  • Location: Leigh On Sea - Essex & Tornado Alley
  • Location: Leigh On Sea - Essex & Tornado Alley

post-24-1212165242_thumb.png

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0748 AM CDT FRI MAY 30 2008

VALID 301300Z - 311200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF

MISSOURI...ILLINOIS...AND INDIANA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN KS INTO THE OH VLY AND

GRT LKS...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE UPR MS VLY...

...SYNOPSIS...

BELT OF FAST WSWLY MID-LEVEL FLOW THAT CROSSED THE CNTRL PLNS/LWR MO

VLY ON THURSDAY WILL CONTINUE E ACROSS MI/IND/OH TODAY AND THE LWR

GRT LKS TONIGHT. UPSTREAM SPEED MAX NOW OVER CO SHOULD ALSO

CONTINUE EWD. PARTIAL PHASING OF THAT DISTURBANCE WITH NRN STREAM

TROUGH NOW DROPPING SE ACROSS ND EXPECTED TO RESULT IN A BROAD BAND

OF FAST WLY FLOW OVER THE MID MS VLY BY THIS EVENING.

A LWR LEVELS...SFC WAVE ASSOCIATED WITH LEAD SPEED MAX SHOULD MOVE

FROM SE MN THIS MORNING TO NEAR GEORGIAN BAY BY 12Z SATURDAY. THE

EFFECTIVE COLD FRONT WITH THE WAVE LIKELY WILL BE COMPOSITE OUTFLOW

BOUNDARY ASSOCIATED WITH OVERNIGHT CONVECTION THAT ATTM EXTENDS FROM

LWR MI WSW TO NRN MO. THE OUTFLOW BOUNDARY SHOULD EXTEND FROM SRN

MI WSW INTO NRN/CNTRL IL INTO CNTRL MO/S CNTRL KS BY THIS AFTN.

FARTHER NW...SEVERAL WEAK BOUNDARIES/TROUGHS WILL EXIST IN

ASSOCIATION WITH NRN STREAM IMPULSE OVER THE ERN DAKS...NRN/CNTRL

MN...AND WI/IA.

...GRT LKS/OH VLY WSW INTO MID MS VLY/MO/KS...

DESPITE LIMITED SFC-BASED INSTABILITY...ONGOING MESO-BETA SCALE

CONVECTIVE FEATURES WITH SMALL BOWS AND EMBEDDED ROTATING STORMS MAY

CONTINUE TO POSE A RISK FOR LOCALLY DMGG WIND GUSTS AND ISOLD

TORNADOES THIS MORNING FROM ERN IA/NERN MO INTO NRN IL AS

PREVIOUSLY-MENTIONED LEAD SPEED MAX CONTINUES E TOWARD THE LWR GRT

LKS.

LATER TODAY...SFC HEATING AND CONTINUED LOW-LEVEL MOISTURE INFLOW

SHOULD SUPPORT FAIRLY STRONG DESTABILIZATION ALONG AND AHEAD OF

COMPOSITE OUTFLOW BOUNDARY FROM ERN KS ENE INTO IL/IND. SBCAPE

SHOULD REACH 3000 J/KG OVER ERN KS AND MO...WITH VALUES AOA 2000

J/KG EWD INTO IND.

DESTABILIZATION AND ASCENT ASSOCIATED WITH CO DISTURBANCE SHOULD

SUPPORT VIGOROUS NEW TSTM DEVELOPMENT THIS AFTN ALONG OUTFLOW

BOUNDARY FROM ERN KS INTO CNTRL AND NRN PARTS OF MO/IL. EXISTING

STORMS ALSO MAY STRENGTHEN OVER IL/SRN MI AND NRN IND.

ALTHOUGH THE 850 MB WARM SECTOR FLOW WILL BE SIGNIFICANTLY VEERED

RELATIVE TO YESTERDAY...STRENGTHENING WINDS AT 500 MB /WITH SPEEDS

AOA 50 KTS/ WILL YIELD LONG...SLIGHTLY HOOKED HODOGRAPHS. COUPLED

WITH THE DEGREE OF INSTABILITY...RESULTING SUPERCELL STORMS COULD

YIELD A FEW TORNADOES...IN ADDITION TO LARGE HAIL AND HIGH WIND.

THIS THREAT SHOULD BE GREATEST IN THE MODERATE RISK AREA FROM MO

INTO IL/IND.

WITH THE MEAN WIND FIELD EXPECTED TO CONTINUE STRENGTHENING AND

BECOME INCREASINGLY UNIDIRECTIONAL THIS EVENING...ONE OR MORE

FORWARD-PROPAGATING CLUSTERS /BOW ECHOES/ SHOULD EVOLVE OVER ERN

MO/IL AND IND. AND...WITH THE LOW-LEVEL AIRMASS RECOVERY CONTINUING

ACROSS THE REGION OVERNIGHT...THIS ACTIVITY COULD REACH THE LWR GRT

LKS AND UPR OH VLY BY 12Z SATURDAY. THE STRONGEST STORMS SHOULD

OCCUR NEAR EXPECTED LOW-LEVEL THETA-E ADVECTION MAXIMUM OVER

IND/OH...WHERE DMGG WINDS MAY OCCUR WELL INTO THE NIGHT. FARTHER

W...MOST OF THE STORMS SHOULD WEAKEN AS SBCINH STRENGTHENS W OF THE

MS RVR. A FEW SPOTS OF STRONG TO POSSIBLY BRIEFLY SVR STORMS

COULD...HOWEVER...PERSIST THROUGH 12Z SATURDAY IN EXIT REGION OF

DIURNALLY-ENHANCED LLJ OVER SRN KS/NRN OK.

...UPR MS VLY/NRN PLNS...

WELL NW OF THE MAIN SVR THREAT AREA IN THE MIDWEST/ERN PLNS...A

SEPARATE REGION OF WDLY SCTD...DIURNAL SVR STORMS MAY EVOLVE IN

MODERATE BUT DEEP CYCLONIC W TO WNWLY FLOW ON BACK SIDE OF NRN

STREAM TROUGH. 500 MB COLD POOL WITH TEMPERATURES AOB MINUS 16C

WILL OVERLAY MID TO UPR 50S F SFC DEW POINTS. COUPLED WITH

CONFLUENT CYCLONIC FLOW AT THE SFC...SETUP COULD SUPPORT DEVELOPMENT

OF A FEW AREAS OF STORMS ORGANIZED INTO BANDS OR CLUSTERS FROM THE

NRN HI PLNS ESE INTO THE UPR MS VLY. MODEST DEEP SHEAR SHOULD KEEP

ACTIVITY MULTICELL...BUT SUFFICIENT CAPE MAY DEVELOP FOR SVR HAIL

AND POSSIBLY LOCALLY DMGG WIND. SLIGHTLY ELEVATED TSTMS ARE ALREADY

PRESENT IN ERN SD/WRN MN...AND ADDITIONAL ACTIVITY SHOULD FORM WITH

HEATING ALONG CLOUDY-CLEAR BOUNDARY OVER THE REGION LATER TODAY.

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Posted
  • Location: SE London
  • Location: SE London

tornado watch #393 has changed shape a few times today, seems to be going in a westerly direction from the origin it was this morning.

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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

I noticed there was a 60 knot wind over central KS at 850 mb this morning ... from the guidance, I expect the eventual development will be close to the KS-OK border, and possibly Bartlesville OK might be the eventual target although cells may initiate in s/c KS but watch for backbuilding and a stronger frontal zone to develop from about Springfield MO to about Pawnee OK during the late afternoon. The eventual frontal boundary will be defined by northern edge of 22-24 C dew points that are developing across parts of se KS at present time.

While not all of interest to the storm chase, I would still rate this as a moderate risk of severe storms especially in southern MI, n IN and central IL to s/c MO and then also into se KS and ne OK. There could also be some development around Lubbock TX with the next wave forming up.

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Posted
  • Location: South Shields Tyne & Wear half mile from the coast.
  • Location: South Shields Tyne & Wear half mile from the coast.

Meso discussion concerning severe potential.

MCD - 30/2100Z

ACUS11 KWNS 301923

SWOMCD

SPC MCD 301923

MOZ000-KSZ000-OKZ000-302100-

MESOSCALE DISCUSSION 1099

NWS STORM PREDICTION CENTER NORMAN OK

0223 PM CDT FRI MAY 30 2008

AREAS AFFECTED...SE KS...NRN MO

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 301923Z - 302100Z

AN ISOLATED SEVERE THREAT WILL LIKELY DEVELOP OVER THE NEXT FEW

HOURS AS STORMS INITIATE AND INCREASE IN COVERAGE ACROSS PARTS OF

ERN KS AND NCNTRL MO. A FEW TORNADOES...LARGE HAIL AND ISOLATED WIND

DAMAGE WILL BE POSSIBLE AND A WW WILL LIKELY BE NECESSARY BY 20Z.

LATEST SFC ANALYSIS SHOWS A TRIPLE POINT OVER FAR NW MO WITH A COLD

FRONT EXTENDING SSWWD ACROSS ERN KS. EAST OF THE FRONT...STRONG

INSTABILITY IS IN PLACE WITH OBJECTIVE FIELDS INDICATING SBCAPE

VALUES OF 3000 TO 4000 J/KG. IN ADDITION...A BROAD MID-LEVEL JET

AXIS IS LOCATED ACROSS NRN KS AND NRN MO AND THIS FEATURE IS

CREATING MODERATE VERTICAL SHEAR PROFILES WHICH WILL BE FAVORABLE

FOR SUPERCELLS. A 40 TO 50 KT LOW-LEVEL JET ORIENTED FROM NRN OK

ACROSS NRN MO WILL CREATE LOW-LEVEL SHEAR PROFILES SUFFICIENT FOR A

FEW TORNADOES. THE STRONG INSTABILITY WILL BE SUFFICIENT FOR STRONG

UPDRAFTS WITH LARGE HAIL POTENTIAL. IN ADDITION...RELATIVELY HIGH

SFC DEWPOINTS IN THE UPPER 60S F AND LOWER 70S F AND STEEPENING

LAPSE RATES WILL BE FAVORABLE FOR ISOLATED WIND DAMAGE.

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Posted
  • Location: South Shields Tyne & Wear half mile from the coast.
  • Location: South Shields Tyne & Wear half mile from the coast.

Tornado watch..

TornadoWatch - 0300Z

WWUS20 KWNS 301944

SEL5

SPC WW 301944

KSZ000-MOZ000-OKZ000-310300-

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 395

NWS STORM PREDICTION CENTER NORMAN OK

245 PM CDT FRI MAY 30 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

SOUTHEAST KANSAS

WESTERN AND CENTRAL MISSOURI

FAR NORTHEAST OKLAHOMA

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 245 PM UNTIL

1000 PM CDT.

TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE

MILES EAST AND WEST OF A LINE FROM 20 MILES EAST SOUTHEAST OF

BARTLESVILLE OKLAHOMA TO 20 MILES NORTHWEST OF KIRKSVILLE

MISSOURI. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 394...

DISCUSSION...CAP IS ERODING QUICKLY WITH STRONG HEATING AHEAD OF

APPROACHING SURFACE COLD FRONT THIS AFTERNOON...WHICH WILL SUPPORT

THUNDERSTORM DEVELOPMENT THROUGH THE EVENING. AIR MASS IS VERY

UNSTABLE WITH EFFECTIVE SHEAR OF 40-50 KT FAVORING

SUPERCELLS...LIKELY SPLITTING WITHIN UNIDIRECTIONAL SHEAR. ALONG

WITH LARGE HAIL AND ISOLATED DAMAGING WINDS...LOW LEVEL SHEAR SHOULD

REMAIN SUFFICIENT FOR TORNADO THREAT DESPITE THE VEERED LOW LEVEL

FLOW /ESPECIALLY WITH RIGHT SPLITS/.

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Posted
  • Location: Rossland BC Canada
  • Location: Rossland BC Canada

So far today, there's a ragged band of severe if non-tornadic storms from central Missouri east to northern Indiana, and so far in southeast KS and northeast OK, a stubborn cap over a cumulus field of modest proportions. It could break just around sunset and let one or two CBs develop. We'll see ... but it looks a bit marginal at the moment.

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Posted
  • Location: South Shields Tyne & Wear half mile from the coast.
  • Location: South Shields Tyne & Wear half mile from the coast.

Yes Roger it does seem very marginal latest visible image shows the

cumulus field quite clearly,.

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