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July 26-27 Severe Threat

Hoosier

By Hoosier,
in Lakes/Ohio Valley

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Hoosier

Hoosier

Posted
Posted 
   DAY 3 CONVECTIVE OUTLOOK     NWS STORM PREDICTION CENTER NORMAN OK   0229 AM CDT THU JUL 24 2014   VALID 261200Z - 271200Z   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL PLAINS TO THE OH   VALLEY/LOWER GREAT LAKES...   ...SUMMARY...   CLUSTERS OF SEVERE STORMS WILL BE POSSIBLE FROM THE CENTRAL GREAT   PLAINS TO THE GREAT LAKES AND CENTRAL APPALACHIANS.   ...SYNOPSIS...   A VIGOROUS MID-LEVEL CYCLONE OVER THE SRN PRAIRIE PROVINCES WILL   ACCELERATE SE INTO THE UPPER MIDWEST BY EARLY SUN. A BROAD BELT OF   STRONG MID-LEVEL WLYS SHOULD BE PREVALENT FROM THE NRN PLAINS TO THE   LOWER GREAT LAKES. AT THE SURFACE...A QUASI-STATIONARY FRONT SHOULD   BE DRAPED ACROSS PARTS OF THE CNTRL PLAINS TO LOWER GREAT LAKES. AN   OCCLUDED FRONT WILL EXTEND S OF THE PRIMARY CANADIAN CYCLONE ACROSS   THE UPPER MIDWEST.   ...CNTRL PLAINS TO OH VALLEY/LOWER GREAT LAKES...   S OF THE QUASI-STATIONARY FRONT...A STRONG TO EXTREMELY UNSTABLE AIR   MASS SHOULD BE PRESENT FROM PARTS OF THE CNTRL PLAINS TO MIDWEST AS   THE PLAINS EML PLUME IS ADVECTED E TOWARDS THE NRN APPALACHIANS.   WAA-DRIVEN ELEVATED TSTM CLUSTERS SHOULD BE ONGOING AT 12Z/SAT OVER   PARTS OF THE MIDWEST. IN THE WAKE OF THIS ACTIVITY...CAPPING SHOULD   LARGELY INHIBIT SURFACE-BASED TSTM DEVELOPMENT UNTIL LATE DAY. THE   DEGREE OF INHIBITION SHOULD GENERALLY BE LESS COMPARED TO D2...OWING   TO MINOR HEIGHT FALLS AND COOLER 700 MB TEMPERATURES /ESPECIALLY E   OF THE MS RIVER/.    SCATTERED CLUSTERS OF STORMS SHOULD FORM BY EVENING WITHIN THE   FRONTAL ZONE. GIVEN THE DEGREE OF INSTABILITY...ALONG WITH   STRENGTHENING DEEP-LAYER SHEAR...AN ORGANIZED MCS OR TWO MAY   DEVELOP. LARGE HAIL WILL BE MOST PROBABLE DURING THE LATE AFTERNOON   AND EVENING...WITH POTENTIAL FOR ONE OR MORE SWATHS OF DAMAGING   WINDS DURING THE EVENING INTO SAT NIGHT. IF SHORTER-TERM MESOSCALE   PREDICTABILITY INCREASES...CORRIDORS OF HIGHER SEVERE PROBABILITIES   MAY BECOME EVIDENT IN LATER OUTLOOKS.    ...UPPER MS VALLEY...   DEEP-LAYER SHEAR WILL BE FAVORABLE FOR ORGANIZED CONVECTION ALONG   THE OCCLUDED FRONT SAT AFTERNOON/EVENING. THE PRIMARY UNCERTAINTIES   ARE -- 1) RICHER LOW-LEVEL MOISTURE REMAINING S OF THE CNTRL PLAINS   TO MIDWEST FRONT...2) POTENTIAL ELEVATED STORMS OVER SD LATE D2   HINDERING DIURNAL DESTABILIZATION AND 3) STRENGTH OF CONVERGENCE   ALONG THE OCCLUDED FRONT. STILL...AN ISOLATED SEVERE HAIL AND   LOCALLY DAMAGING WIND THREAT APPEARS POSSIBLE.   ..GRAMS.. 07/24/2014

post-14-0-17972300-1406216593_thumb.gif

 

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snowlover2

snowlover2

Posted
Posted

Both ILN and IND have impressive AFD's. Haven't seen anything out of ILN like this in a long long time.

 

 

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
THIS PERIOD WILL BE CHARACTERIZED BY A LARGE SWING/CHANGE IN
AIRMASSES AND QUIESCENT WEATHER ON FRIDAY MORNING TO POTENTIAL
SEVERE STORMS AND HEAVY RAINFALL BY SATURDAY NIGHT.

AT 25.12Z...595DM 500MB ANTICYCLONE WILL REMAIN SITUATED OVER NEW
MEXICO WITH A VERY DYNAMIC AND ANOMALOUS CLOSED LOW CRESTING THE
RIDGE OVER SASK/ALBERTA...FLATTENING THE RIDGE SOMEWHAT. THE
PERSISTENT ERN CONUS LONGWAVE TROUGH WILL STILL EXIST IN A
POSITIVE TILT FASHION FROM LA/AL NORTHEAST THROUGH THE UPPER OHIO
VALLEY WHERE A CYCLONE WILL EXIST EAST OF HUDSON BAY.

THROUGH THE DAY FRIDAY...THE CLOSED LOW WILL MOVE SLOWLY EASTWARD
WHILE THE RIDGE IN THE WEST FLATTENS...WHICH DEAMPLIFIES THE ERN
CONUS LONGWAVE TROUGH FURTHER AND SHUNTS IT EAST. AS SUCH...SFC
HIGH PRESSURE AND COOL/DRY WEATHER WILL BUILD EASTWARD WITH RETURN
FLOW BEGINNING TO OUR WEST. THE BULK OF FRIDAY WILL BE
GORGEOUS...LOW HUMIDITY...MIX OF SUN AND CLOUDS AND TEMPS
REBOUNDING INTO THE UPPER 70S.

THAT IS WHERE MORE SIGNIFICANT CHANGES BEGIN AND THE ENTRY POINT
INTO WHAT WILL LIKELY BE AN ACTIVE WEEKEND. BY SATURDAY MORNING
THE POTENT CLOSED LOW WILL BE APPROACHING LAKE WINNIPEG WHILE A
MORE SUBTLE SHORTWAVE TROUGH IS EJECTED ATOP THE FLATTENING NERN
QUADRANT OF THE WRN RIDGE...DOWN THE SLIDE OF INCREASINGLY FAST
WNWLY MID LEVEL FLOW INTO THE GREAT LAKES. ON THE NOSE OF A LOW
LEVEL MOISTURE TRANSPORT MAXIMUM...AND AT THE EDGE OF AN STRONG
PLAINS-BASED ELEVATED MIXED LAYER /WARM...DRY...STEEP LAPSE RATE
ENVIRONMENT/...CONVECTIVE INSTABILITY WILL BE ADVECTED IN FROM THE
WEST LATER FRIDAY NIGHT WITH MUCAPE SIGNIFICANTLY INCREASING ABOVE
THE EML LATER IN THE NIGHT. AN MCS OR TWO IS LIKELY TO BE MANIFESTED
ON THE LEADING EDGE OF THESE ENTITIES...AND WILL BE APPROACHING
THE AREA FRIDAY NIGHT/SAT MORNING WITH TIMING/LOCATION VERY MUCH IN
DOUBT. PWAT WILL DOUBLE /0.60" TO 1.20"/ IN LESS THAN 12 HOURS AS
THIS DESTABILIZATION ALOFT TAKES PLACE. CONFIDENCE ON WHERE THIS
ACTIVITY MOVES IS NOT HIGH...BUT DID INCREASE THE SHOWER/STORM
CHANCES FRIDAY NIGHT INTO SATURDAY MORNING OVER A LARGE PORTION OF
THE AREA TO ACCOUNT FOR THIS POTENTIAL. PER 25.12Z
ECMWF/GFS/NAM...SOMEWHERE IN INDIANA/NORTHERN OHIO SEEMS THE BEST
BET AT 12Z SAT MORNING.

AS THE REMNANTS OR WHAT REMAINS OF ANY STORM ACTIVITY MOVES ACROSS
THE AREA SATURDAY MORNING...HEIGHTS WILL CONTINUE TO SLOWLY RISE IN THE
WAKE OF THE LEAD SHORTWAVE TROUGH AND AHEAD OF THE POTENT CLOSED
LOW NOW DIGGING INTO MINNESOTA. THE EML WILL BECOME ENTRENCHED
OVER THE AREA WITH POINT FCST /BUFR/ SOUNDINGS FROM 25.12Z NAM AND
GFS BOTH SHOWING STRONG INHIBITION FROM LATE MORNING
THROUGH THE BULK OF THE AFTERNOON. THUS...ATTEMPTED TO SHOW A
REDUCTION IN RAIN CHANCES DURING THIS TIME...AS MLCINH ON MANY
SOUNDINGS EXCEEDS 200 J/KG AND IN SOME DATA EXCEEDS 300
J/KG. THIS SHOULD PROMOTE A WARM...INCREASINGLY HUMID DAY WITH
DECREASING ELEVATED STORM THREATS...WITH DEWPOINTS RISING TOWARD
70F AND AIR TEMPS IN THE MID/UPPER 80S.

SATURDAY EVENING/OVERNIGHT...CONFIDENCE IS LOW ON THE DETAILS BUT
A RENEWED LOW LEVEL JET/MOISTURE TRANSPORT SIGNAL WILL DEVELOP
AHEAD OF THE DIGGING MN/WI CLOSED LOW...POINTED INTO IL/IN/OH.
THERE MAY BE OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES FROM SAT
MORNING CONVECTION...BUT EITHER WAY FORCING BECOMES GOOD ENOUGH
AND A SIGNAL CROPS UP IN THE DATA FOR NOCTURNAL MCS
POTENTIAL...WHICH COULD BE ANYWHERE FROM OHIO BACK INTO ILLINOIS.
THIS MAY BE INITIALLY ROOTED ABOVE THE CAP BUT GIVEN RESERVOIR OF
STRONG INSTBY AMIDST THE EML...AND IMPRESSIVE SHEAR...THERE IS
CONCERN FOR AN ORGANIZED SEVERE WEATHER EVENT SAT NIGHT INTO
SUNDAY MORNING WITH PRIMARY FOCUS OF DAMAGING WIND VIA FORWARD
PROPAGATING CONVECTIVE SYSTEM. IN FACT...CIPS ANALOGS INDICATES
THAT THE SYNOPTIC PATTERN INGREDIENTS AS BEING PREDICTED BY THE
25.12Z NAM HAS PRODUCED A NUMBER OF WIND-PRODUCING MCS SYSTEMS
ACROSS THE CORN BELT/OHIO VALLEY. A CLOSER LOOK AT THE DETAILS
/EVENTS WITHIN THE PATTERN MATCH -- TOP 15 ANALOGS ON VARIOUS
DOMAINS/ SHOWS A COUPLE HIGHER-END EVENTS OF EITHER IN TERMS OF
AREA AFFECTED OR NUMBER OF REPORTS...AND THESE SIGNALS WERE
PRESENT ON 25.00Z GFS PATTERN MATCHES...SO FEEL CONFIDENT IN
BEGINNING TO RAISE AWARENESS OF THIS POTENTIAL IN HAZ WX OUTLOOK
PRODUCT FOR SAT INTO SUNDAY. DEGREE OF INSTBY AND 0-3KM SHEAR ARE
FAVORABLE.

LURKING IN THE TALL GRASS IS HEAVY RAIN POTENTIAL WITH GEFS
REFORECAST PROBABILITIES SUGGESTING THAT RAIN AMOUNTS BEING
SUGGESTED BY ENSEMBLE MEAN /ALREADY DECENT/ MAY ACTUALLY BE UNDERDONE IN
THIS MULTI-MCS SCENARIO OVER SATURDAY/SUNDAY. WPC ALREADY RUNNING
SLGT RISKS FOR EXCESSIVE RAINFALL ON DAY 3 /SAT AND SAT NIGHT/
WHICH SEEMS REASONABLE BASED ON REFORECAST DATA AND 25.12Z
DETERMINISTIC RUNS SHOWING MCS POTENTIAL. 25.00Z NAEFS
PROBABILITIES ALSO CENTERED ON OHIO. WLY LOW LEVEL JET AHEAD OF A
DIGGING UPPER TROUGH /WHICH IS THE PATTERN ON SUNDAY MORNING/ MAY
PROMOTE BACKBUILDING AND TRAINING ON THE SRN FRINGE OF ANY FORWARD
PROPAGATING MCS.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
ACTIVE WEATHER PATTERN WILL BE IN PLACE FOR THE BEGINNING OF THE
LONG TERM PERIOD. MODELS ARE IN GOOD AGREEMENT ON A MCS MOVING
ACROSS THE FA SUNDAY MORNING. THIS FEATURE WILL BRING WIDESPREAD
THUNDERSTORM ACTIVITY ACROSS THE AREA. WITH MODEL AGREEMENT
INCREASED PRECIPITATION CHANCES SIGNIFICANTLY DURING THIS TIME.
THERE IS A DECENT CHANCE OF SEVERE WEATHER WITH THIS FEATURE WITH
DAMAGING WINDS THE PRIMARY THREAT. AN ISOLATED TORNADO CANNOT BE
RULED OUT HOWEVER. WILL ADD MENTION OF THIS THREAT TO THE HWO. IN
ADDITION TO THE SEVERE THREAT THIS FEATURE WILL BRING MODERATE TO
HEAVY RAIN TO THE AREA WHICH MAY LEAD TO SOME FLOODING ISSUES AS
WELL.

ADDITIONAL THUNDERSTORM ACTIVITY WILL BE LIKELY DURING THE AFTERNOON
AND EVENING HOURS ON SUNDAY AS A COLD FRONT APPROACHES AND WORKS
INTO THE REGION. THERE IS QUITE A BIT OF INSTABILITY ACROSS THE
AREA FOR SUNDAY. THERE IS THE ADDITIONAL CHANCE FOR SEVERE WEATHER
SUNDAY AFTERNOON INTO THE EVENING HOURS. DAMAGING WINDS AND LARGE
HAIL WILL BE POSSIBLE. IN ADDITION A TORNADO THREAT WILL ALSO BE
POSSIBLE. SOME QUESTIONS REMAIN ON THE STRENGTH OF THIS SECOND
EVENT AS THIS WILL BE DEPENDENT ON THE FIRST ROUND OF
THUNDERSTORMS. WILL ALSO HIGHLIGHT THIS SEVERE THREAT IN THE HWO.
WITH MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS THERE WILL AGAIN
BE THE THREAT OF FLOODING.

THUNDERSTORMS MOVE OUT OF THE FA SUNDAY NIGHT AND COOLER AIR WILL BE
USHERED INTO THE FA. AN UPPER LEVEL DISTURBANCE ON MONDAY WILL
ALLOW FOR DECENT CLOUD COVER AND SOME SHOWER ACTIVITY. THIS WILL
KEEP TEMPERATURES COOL AND WELL BELOW NORMAL. HIGH TEMPERATURES
ARE ONLY EXPECTED TO BE IN THE LOW TO MID 70S ON MONDAY. HIGH
PRESSURE THEN WORKS INTO THE AREA FOR THE REMAINDER OF THE LONG TERM
ALLOWING FOR DRY CONDITIONS. HIGH TEMPERATURES WILL GRADUALLY WARM
EACH DAY AFTER TUESDAY. TUESDAY LOOKS TO HAVE TO COOLEST HIGH
TEMPERATURES OF THE LONG TERM PERIOD.

 

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snowlover2

snowlover2

Posted
Posted

IND

 

 

 

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 345 PM EDT THU JUL 24 2014

FORECAST CHALLENGES ARE PLENTIFUL...AS THE CURRENT STRETCH OF DRY
PLEASANT WEATHER GIVES WAY TO A MUCH MORE ACTIVE PATTERN WITH
POTENTIALLY MULTIPLE OPPORTUNITIES FOR SEVERE WEATHER OVER THE
WEEKEND.

THE SHORT TERM PERIOD WILL BE HIGHLIGHTED BY A TRANSITION TO A
FAMILIAR THEME THIS SUMMER...AS NORTHWEST FLOW ALOFT DEVELOPS
BETWEEN THE FLATTENED YET STRONG RIDGE OVER THE SOUTHERN HIGH PLAINS
AND AN ANOMALOUSLY STRONG UPPER LOW TRACKING ACROSS THE CANADIAN
PRAIRIES. THE UPPER LOW WILL MOVE SOUTHEAST OVER THE WEEKEND...
EVENTUALLY ARRIVING OVER THE GREAT LAKES BY SUNDAY. IN DOING
SO...THE UPPER WAVE WILL ASSIST IN FORCING THE RIDGE WEST INTO THE
FOUR CORNERS REGION WHILE AMPLIFYING OUR OLD FRIEND THE EASTERN
TROUGH.

BY FAR THE PICK DAY OF THE SHORT TERM WILL BE FRIDAY WITH THE REGION
STILL FIRMLY UNDER THE CONTROL OF SLOWLY DEPARTING HIGH PRESSURE.
EXPECT A GOOD DEAL OF SUNSHINE WITH A SLOW BUT STEADY INCREASE IN
MID AND HIGH LEVEL CLOUDS AS WARM FRONTAL CONVECTION TAKES PLACE TO
THE NORTHWEST OF THE FORECAST AREA. NOT OUT OF THE QUESTION THAT
SOME OF THIS CONVECTION MAY MAKE IT INTO THE NORTHERN WABASH VALLEY
PRIOR TO SUNSET FRIDAY...ALBEIT IN A WEAKENED CONDITION AS IT MOVES
INTO A DRIER AND MORE STABLE AIRMASS OVER CENTRAL INDIANA. STORM
COVERAGE IS LIKELY TO INCREASE OVERNIGHT FRIDAY HOWEVER AS A LOW
LEVEL JET NOSES INTO THE MID MISSISSIPPI VALLEY...WITH MOISTURE AND
ELEVATED INSTABILITY INCREASING ACROSS THE NORTHERN HALF OF THE
HOOSIER STATE. WILL CARRY CHANCE POPS FRIDAY NIGHT MAINLY OVER THE
NORTHERN COUNTIES WITH LOWER POPS FURTHER SOUTH.

OTHER THAN SOME INITIAL CONVECTIVE DEBRIS SATURDAY MORNING...SURGE
OF WARM AND INCREASINGLY HUMID AIR WILL QUICKLY ADVECT INTO THE OHIO
VALLEY...MAKING THE PLEASANT CONDITIONS EXPERIENCED TODAY AND
TOMORROW A LONG DISTANT MEMORY. CONVECTIVE REDEVELOPMENT SATURDAY
AFTERNOON IS THERE...BUT SOME QUESTIONS DO EXIST THAT MAKE
CONFIDENCE LOWER THAN DESIRED AT THIS POINT ON SEVERE WEATHER
POTENTIAL PRIOR TO SATURDAY EVENING. STRONG HEATING OVER THE REGION
SOUTH OF A FRONTAL BOUNDARY WILL SUPPORT A HIGHLY UNSTABLE
ENVIRONMENT WITH PROGRESSIVELY DEEPER MOISTURE ARRIVING DURING THE
DAY. HOWEVER...MODELS CONTINUE TO ADVERTISE A RATHER STOUT CAP WITH
700MB TEMPS AT 12-14C WELL INTO THE AFTERNOON WHICH IS LIKELY TO
LIMIT COVERAGE AND INTENSITY OF STORMS OVER THE REGION. EXPECT
SCATTERED STORMS...WITH A POTENTIAL UPTICK IN COVERAGE TOWARDS
EVENING AS THE CAP WEAKENS.

HIGHEST CONFIDENCE IN POTENTIAL FOR STORMS AND SEVERE WEATHER COMES
SATURDAY NIGHT AS THE CAP COMPLETELY ERODES FOR MUCH OF THE AREA
WHILE A STRONG SURFACE WAVE TRACKS ALONG THE BOUNDARY. WITH ABUNDANT
INSTABILITY...EXCEPTIONALLY DEEP MOISTURE WITH PWATS IN EXCESS OF 2
INCHES BEING FUELED BY THE NOCTURNAL LOW LEVEL JET AND NICE MID AND
UPPER LEVEL FORCING AVAILABLE...SIGNS POINT TOWARDS UPWARD
CONVECTIVE DEVELOPMENT IMPACTING THE FORECAST AREA OVERNIGHT...MOST
LIKELY INTO AN MCS. THE PRESENCE OF DEEPER SHEAR ALSO LENDS ITSELF
TO MORE ORGANIZED ROBUST CONVECTION WITH ALL MODES OF SEVERE WEATHER
ON THE TABLE. TORRENTIAL RAINFALL AND LOCALIZED FLOODING WILL ALSO
BE POSSIBLE WITH THE TROPICAL AIRMASS IN PLACE. FEEL COMFORTABLE IN
INTRODUCING LIKELY POPS SATURDAY NIGHT OVER THE ENTIRE FORECAST
AREA.

SUNDAY FORECAST IS HIGHLY CONDITIONAL ON WHAT OCCURS SATURDAY NIGHT.
WHILE DEEPER MOISTURE WILL BE SHIFTED TO THE SOUTHEAST...STRONGER
UPPER LOW WILL BE ARRIVING INTO THE GREAT LAKES SUNDAY AFTERNOON
WITH RENEWED SURFACE WAVE DEVELOPMENT. AVAILABLE INSTABILITY COULD
BE PROBLEMATIC...ESPECIALLY IF EXPECTED CONVECTION SATURDAY NIGHT
COMPLETELY GRUNGES OUT THE AIRMASS IN ITS WAKE FOR MUCH OF SUNDAY.
WITH THAT BEING SAID...THE PRESENCE OF RENEWED FORCING ALOFT WITH
THE APPROACH OF THE UPPER WAVE SUPPORTS AT THE VERY LEAST A
CONTINUATION OF THE POTENTIAL FOR THUNDERSTORMS AND POSSIBLY ANOTHER
CHANCE FOR SEVERE WEATHER. FOR NOW...WILL CARRY HIGH CHANCE POPS.

TEMPS...GENERALLY TRENDED TOWARDS MAVMOS GUIDANCE FOR TEMPS
THROUGHOUT THE PERIOD WITH THE LONE EXCEPTION OF SATURDAY. MAV SEEMS
OVERLY AGGRESSIVE IN ATTEMPTING TO BRING 90+ AIR INTO THE SOUTHWEST
HALF OF THE FORECAST AREA. WHILE 850MB TEMPS OF 21-22C NOTED ON
MODEL CONSENSUS BY SATURDAY AFTERNOON...THE ARRIVAL OF AN
INCREASINGLY MOIST AND HUMID AIRMASS IS NOT SUPPORTIVE OF WIDESPREAD
90 DEGREE WEATHER... PARTICULARLY IF ANY SCATTERED CONVECTION CAN
FIRE AS WELL. UNDERCUT MAV TEMPS BY 2-4 DEGREES ACROSS THE BOARD.
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JasonOH

JasonOH

Posted
Posted

D2 now mentions a tornado possibility.

THERE IS A SLGT RISK OF SVR TSTMS FROM NERN KS EWD ACROSS THE MIDWEST AND OH RIVER VALLEY... AMENDED FOR OH VALLEY AREA

...SUMMARY...

BOUTS OF SEVERE THUNDERSTORMS CAPABLE OF DAMAGING WINDS APPEAR LIKELY ACROSS MUCH OF THE MIDWEST AND OHIO VALLEY MAINLY SATURDAY NIGHT...WITH SPORADIC DAMAGING WINDS AND HAIL POSSIBLE ACROSS A LARGE AREA FROM EASTERN KANSAS INTO WESTERN PENNSYLVANIA AND NEW YORK DURING THE DAY. ...SYNOPSIS... A LEADING SHORTWAVE TROUGH WILL MOVE QUICKLY EWD ACROSS THE GREAT LAKES AND INTO WRN PA AND NY DURING THE DAY...WITH A MORE SUBSTANTIAL TROUGH AMPLIFICATION ACROSS THE NRN PLAINS LATE IN THE PERIOD. AT THE SURFACE...A COLD FRONT WILL TRAVEL QUICKLY EWD ACROSS WI AND UPPER MI...THEN BECOME STALLED SWWD ACROSS NRN IL...IA...AND NRN MO AND KS THROUGH EVENING. A BROAD BELT OF SWLY WINDS IN THE LOW LEVELS WILL DEVELOP AND BRING SUBSTANTIAL MOISTURE NEWD AHEAD OF THE FRONT WITH 70S DEWPOINTS INTO IL AND INDIANA BY LATE AFTERNOON. CLUSTERS OF THUNDERSTORMS ARE LIKELY DURING THE DAY FROM ERN OH INTO WRN PA AND NY IN ASSOCIATION WITH THE LEAD TROUGH...WITH A MORE SUBSTANTIAL WIND THREAT POSSIBLE FROM IL INTO WRN OH OVERNIGHT AS LIFT INCREASES WITH THE LARGER TROUGH AMPLIFICATION.

...LOWER MO VALLEY EWD ACROSS THE OH VALLEY... EARLY DAY STORMS ACROSS INDIANA AND OH SHOULD LIFT RAPIDLY NEWD WITH A MOIST AND UNSTABLE AIR MASS DEVELOPING WITH FULL HEATING TO THE W. WEAK FORCING NEAR THE FRONT MAY LEAD TO A FEW STRONG STORMS DURING THE DAY WITH A WIND AND HAIL THREAT. HOWEVER...THE GREATEST SEVERE WIND POTENTIAL APPEARS TO BE DURING THE EVENING AND OVERNIGHT...FROM CENTRAL IL EWD ACROSS INDIANA...NRN KY AND WRN OH. MODELS ARE IN GOOD AGREEMENT SHOWING A CORRIDOR OF STRONG STORMS...PERHAPS A SEVERE MCS. GIVEN FAVORABLE LARGE-SCALE FORCING FOR ASCENT...PRECIPITABLE WATER VALUES AROUND 2.00 INCHES AND INCREASING SHEAR PROFILES OVERNIGHT...SIGNIFICANT WIND GUSTS WILL BE POSSIBLE. HOWEVER...UNCERTAINTIES REGARDING HOW EARLIER STORMS WILL AFFECT THE AIR MASS WILL PRECLUDE HIGHER PROBABILITIES AT THIS TIME. IN ADDITION...FORECAST HODOGRAPHS ALSO FAVOR SUPERCELLS SHOULD THE STORMS NOT MELD TOGETHER SO QUICKLY. GIVEN THIS POSSIBLE STORM MODE...A COUPLE TORNADOES COULD OCCUR.

...WRN PA...WRN NY...ERN OH... LIFT FROM WARM ADVECTION NEAR AN EFFECTIVE WARM FRONT AND IN ASSOCIATION WITH THE LOW-AMPLITUDE FEATURE MOVING ACROSS THE GREAT LAKES SHOULD RESULT IN SCATTERED STORMS BY EARLY AFTERNOON. VEERING WINDS WITH HEIGHT AND FAVORABLE FLOW ALOFT INDICATE A THREAT OF SUPERCELLS CAPABLE OF HAIL...LOCALLY DAMAGING WIND AND PERHAPS A TORNADO.

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geddyweather

geddyweather

Posted
Posted

Don't know why anyone hasn't mentioned this, but the D3 slight risk mentions the risk of supercells & tornadoes, along with the conditional probability of a strong tornado, along the outflow boundary from the previous evening's MCS for Srn OH, Ern KY, and parts of WV. Also, there is a very large hatched area across OH, central IN, KY, and parts of WV and TN. Mentions very large hail in this area as well. post-12193-0-68673000-1406297935_thumb.jpost-12193-0-25051000-1406297946_thumb.j

G

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bdgwx

bdgwx

Posted
Posted

There are some big differences in the storm scale modeling vs the regional/global modeling for tomorrow. The 4km NAM nest and both HRW flavors are showing a 2nd equally (or more) significant area of activity in Nebraska moving southeast into KS or IA/MO depending on which variation you look at. The SPC mentioned this activity in the outlook text but declined to spread the 30% area to include it. I wonder if we'll see some big changes coming for the first D1 outlook.

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