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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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