SPC MD 1565

MD 1565 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF THE TX PANHANDLE NEWD THROUGH CNTRL KS INTO NERN KS AND FAR NWRN MO

MD 1565 Image


MESOSCALE DISCUSSION 1565
NWS STORM PREDICTION CENTER NORMAN OK
0450 PM CDT TUE JUL 28 2015

AREAS AFFECTED...PORTIONS OF THE TX PANHANDLE NEWD THROUGH CNTRL KS
INTO NERN KS AND FAR NWRN MO

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 282150Z - 290015Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORM DEVELOPMENT IS FORECAST TO OCCUR WITHIN THE
NEXT FEW HOURS...AND A FEW SEVERE THUNDERSTORMS WILL BE POSSIBLE
INTO THE EVENING HOURS. CONVECTIVE TRENDS WILL BE MONITORED ACROSS
THE AREA.

DISCUSSION...A SLOW-MOVING/STALLING SFC BOUNDARY IS ANALYZED FROM
NEAR BEATRICE NEB TO E OF DODGE CITY KS TO AMARILLO TX...AND
INSTABILITY IS BECOMING STRONG ALONG AND ON THE WARM SIDE /E AND S
SIDE/ OF THE BAROCLINIC ZONE. MLCAPE VALUES ARE ESTIMATED TO BE
BETWEEN 3000 AND 4000 J/KG WITH LITTLE INHIBITION REMAINING. VISIBLE
SATELLITE IMAGERY INDICATES PATCHY...BOUNDARY-LAYER-BASED CUMULUS
FIELDS BECOMING INCREASINGLY AGITATED INVOF THE BOUNDARY AS THE PBL
HAS DEEPENED WITH SFC TEMPS HAVING REACHED 95-103F ON THE WARM SIDE
OF THE BOUNDARY.

PRESENT INDICATIONS ARE THAT ISOLATED TO SCATTERED THUNDERSTORMS
WILL DEVELOP DURING THE NEXT FEW HOURS AND BECOME INTENSE OWING TO
THE STRONG INSTABILITY. STEEP LOW-LEVEL LAPSE RATES ASSOCIATED WITH
DCAPE AROUND 1200-1600 J/KG WILL CONTRIBUTE TO STRONG DOWNDRAFTS
WITH A FEW SVR WIND GUSTS POSSIBLE. THE LARGE DEGREE OF BUOYANCY MAY
ALSO SUPPORT SOME SVR HAIL POTENTIAL. FURTHERMORE...THE STALLING
NATURE OF THE BOUNDARY MAY PROVIDE SOME FRONTAL-ZONE RESIDENCE TIME
FOR TSTMS TO INTERACT WITH RELATED BOUNDARY-ENHANCED VERTICAL
VORTICITY TO BE STRETCHED FOR A NON-ZERO -- ALBEIT LOW -- TORNADO
POTENTIAL.

HOWEVER...EFFECTIVE BULK SHEAR MAGNITUDES OVER 25 KT ARE GENERALLY
DISPLACED TO THE COOL SIDE OF THE BOUNDARY WHERE SVR POTENTIAL WILL
BE VERY LIMITED IN THE HIGH-MLCINH ENVIRONMENT. AS SUCH...TSTMS MAY
STRUGGLE TO ORGANIZE ACROSS THE REGION...LIMITING THE OVERALL
COVERAGE OF SVR POTENTIAL...LIKELY PRECLUDING WW ISSUANCE.
REGARDLESS...TRENDS WILL CONTINUE TO BE MONITORED -- PARTICULARLY IN
NERN KS TO FAR NWRN MO THAT WILL BE IN CLOSER PROXIMITY TO THE TAIL
END OF A GLANCING MID-LEVEL PERTURBATION LOCALLY ENHANCING
ISENTROPIC ASCENT IN THESE AREAS. SLIGHTLY STRONGER DEEP SHEAR
RELATED TO THIS FEATURE MAY ENCOURAGE AN EVOLUTION TO MORE ORGANIZED
MULTICELL CONVECTIVE CLUSTERS WITH A SOMEWHAT GREATER SVR RISK.

..COHEN/HART.. 07/28/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...EAX...TOP...ICT...OUN...GID...DDC...AMA...

LAT...LON   39799726 39949478 39619450 39349500 38809632 38139734
            36130013 35120209 35280259 35660240 38089959 39799726 

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SPC MD 1552

MD 1552 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR EXTREME NORTHEAST WY…EXTREME SOUTHEAST MT…AND WESTERN SD

MD 1552 Image


MESOSCALE DISCUSSION 1552
NWS STORM PREDICTION CENTER NORMAN OK
0350 PM CDT MON JUL 27 2015

AREAS AFFECTED...EXTREME NORTHEAST WY...EXTREME SOUTHEAST MT...AND
WESTERN SD

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 272050Z - 272215Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...SEVERE WEATHER THREAT IS EXPECTED TO INCREASE ACROSS
EXTREME NORTHEAST WY AND EXTREME SOUTHEAST MT INTO WESTERN SD THIS
AFTERNOON INTO THE EVENING...WITH A SEVERE WEATHER WATCH ISSUANCE TO
BE COORDINATED SOON FOR THIS REGION AND LOCATIONS FARTHER NORTH AS
DISCUSSED IN MCD 1551.

DISCUSSION...TRENDS IN LIGHTNING DATA...GOES-R CLOUD-TOP COOLING
PRODUCT AND RADAR IMAGERY INDICATED A RELATIVELY RAPID INCREASE IN
TSTM INTENSITIES WITH STORMS TRACKING TO THE NNE ACROSS FAR NE WY
AND FAR WRN SD IN VICINITY OF A COLD FRONT IN FAR ERN WY AND A N-S
ORIENTED PRE-FRONTAL BOUNDARY.  THE PRESENCE OF STEEP MIDLEVEL LAPSE
RATES AND STRONG INSTABILITY NEAR AND EAST OF THESE BOUNDARIES
FAVORS SUSTAINED/STRONG UPDRAFTS...WHILE STRENGTHENING BULK SHEAR
WILL ENHANCE THE LIKELIHOOD FOR ORGANIZATION.  THE RECENT INCREASE
IN STORM INTENSITIES IS LIKELY INDICATING THE LEADING EXTENT OF
STRONG FORCING FOR ASCENT SPREADING ACROSS THE NORTHERN PLAINS THIS
AFTERNOON WITH THE APPROACH OF THE UPSTREAM...PROGRESSIVE SHORTWAVE
TROUGH.

..PETERS/GOSS.. 07/27/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BIS...LBF...UNR...CYS...BYZ...

LAT...LON   44350564 45970428 46010238 44710180 43830196 42970203
            43020385 43530438 43590516 44350564 

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SPC MD 1550

MD 1550 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR CENTRAL AND SOUTHERN IA

MD 1550 Image


MESOSCALE DISCUSSION 1550
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM CDT MON JUL 27 2015

AREAS AFFECTED...CENTRAL AND SOUTHERN IA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 271740Z - 272045Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A RELATIVELY COMPACT MCS WILL ADVANCE TO THE EAST ACROSS
CENTRAL AND PORTIONS OF SOUTHERN IA THIS AFTERNOON.  ALTHOUGH MOST
OF THE WIND GUSTS ASSOCIATED WITH THIS ACTIVITY SHOULD REMAIN
SUB-SEVERE...LOCALLY STRONG WIND GUSTS /POTENTIALLY REACHING OR
EXCEEDING 50 KT/ CANNOT BE RULED OUT.

DISCUSSION...DMX RADAR TRENDS AND PERSISTENT CLOUD-TOP COOLING PER
IR SATELLITE IMAGERY INDICATED A FORWARD-PROPAGATING LINEAR MCS
ADVANCING EASTWARD ACROSS CENTRAL IA.  AS THE STORMS MOVED THROUGH
THE COUNTIES OF BOONE...DALLAS...AND MADISON THE ATTENDANT OUTFLOW
BOUNDARY HAD MOVED AHEAD OF THE STRONGER BAND OF STORMS INDICATING
ANY STRONGER WIND GUSTS ATTENDANT TO THIS MCS MAY NOT BE REACHING
THE SURFACE.  HOWEVER...IF THE STRONGER ACTIVITY CAN OVERTAKE THE
OUTFLOW BOUNDARY...AS MAY BE ONGOING IN NORTHEAST DALLAS COUNTY AND
PORTIONS OF WESTERN POLK COUNTY...THEN 55+ KT WLY WINDS OBSERVED
AROUND 500 FEET AGL IN THAT PORTION OF DALLAS COUNTY WILL HAVE A
GREATER POTENTIAL TO REACH THE SURFACE.

GIVEN THE ORGANIZATION OF THIS MCS WITH AN ACCOMPANYING COLD POOL
AND REAR-INFLOW JET OF 40-45 KT AT 1-2 KM AGL PER DMX RADAR 
COMBINED WITH A SURFACE-BASED INFLOW REGIME THAT HAS MODERATELY
STRONG INSTABILITY...THIS COMPLEX IS EXPECTED TO PERSIST THROUGH THE
AFTERNOON...TRACKING TO EAST ALONG AN INSTABILITY GRADIENT.  AN
EVENTUAL SOUTHEASTWARD TURN MAY OCCUR BETWEEN 19-20Z AS THE SOUTHERN
FLANK REACHES POWESHIEK AND MAHASKA COUNTIES WHERE THE INSTABILITY
GRADIENT IS ORIENTED NW-SE.  ALTHOUGH SHORT-TERM MODELS HAVE HAD
DIFFICULTY FORECASTING THIS COMPLEX...THE HRRR /THOUGH SLOW WITH ITS
DEVELOPMENT AND PLACEMENT/ SUGGESTS THIS STORM COMPLEX SHOULD
PERSIST THROUGH THE AFTERNOON WITH AN EVENTUAL SEWD MOVEMENT.  ELY
SURFACE WINDS WILL CONTINUE TO ENHANCE DEEP SHEAR FOR STORM
ORGANIZATION...WHILE FORCING FOR ASCENT ATTENDANT TO A WEAK
EWD-MOVING MIDLEVEL IMPULSE AIDS IN SUSTAINING TSTM DEVELOPMENT
WITHIN THIS MCS.

..PETERS/GOSS.. 07/27/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...DVN...DMX...

LAT...LON   41909250 41849204 41549168 40999158 40909197 40899242
            41129292 41339404 41629419 41869415 42029404 41909250 

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SPC MD 1538

MD 1538 CONCERNING SEVERE THUNDERSTORM WATCH 451… FOR KS…NRN MO

MD 1538 Image


MESOSCALE DISCUSSION 1538
NWS STORM PREDICTION CENTER NORMAN OK
0932 PM CDT SAT JUL 25 2015

AREAS AFFECTED...KS...NRN MO

CONCERNING...SEVERE THUNDERSTORM WATCH 451...

VALID 260232Z - 260400Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 451
CONTINUES.

SUMMARY...SEVERE THREAT MAY LINGER FOR ANOTHER 1-2 HOURS ON WESTERN
AND NORTHEASTERN EDGE OF WW 451...BUT A GENERAL DOWNWARD TREND IS
EXPECTED WITH TIME AND NO ADDITIONAL WATCH ISSUANCE IS ANTICIPATED
DOWNSTREAM.

DISCUSSION...THE STRONGEST CONVECTION ACROSS WW 451 AS OF 0230Z IS
IN THE FAR WRN PART ACROSS W-CNTRL KS AND THE FAR NERN PORTION
ACROSS NWRN MO. ACROSS FAR NERN KS/NWRN MO...TWO RELATIVELY
ORGANIZED CONVECTIVE CLUSTERS HAVE EVOLVED OUT OF EARLIER ELEVATED
CONVECTION. THESE CLUSTERS WILL AFFECT THE FAR NERN PORTION OF WW
451 AND AREAS DOWNSTREAM INTO NRN MO. THIS ACTIVITY IS LIKELY BEING
AIDED BY ASCENT ATTENDANT TO A SHORTWAVE CURRENTLY MOVING ACROSS IA
AND MAY PERSIST INTO THE OVERNIGHT HOURS AS IT MOVES ESEWD. IN THE
SHORT TERM...THIS ACTIVITY WILL POSE A THREAT OF LOCALLY DAMAGING
WIND...BUT DECREASING SFC-BASED BUOYANCY WITH TIME SHOULD TEMPER THE
OVERALL SEVERE THREAT AND NO DOWNSTREAM WW ISSUANCE IS ANTICIPATED
AT THIS TIME. 

TO THE WEST...STRONG STORMS ARE ONGOING TO THE NE OF DDC...WITH SOME
BACKBUILDING NOTED ALONG A TRAILING OUTFLOW BOUNDARY. LARGE-SCALE
ASCENT IS NEUTRAL AT BEST IN THIS REGION...SO THIS ACTIVITY SHOULD
BECOME LESS ORGANIZED WITH TIME AS THE THERMODYNAMIC ENVIRONMENT
BECOMES INCREASINGLY UNFAVORABLE. WHILE A LOCAL EXTENSION IN TIME IS
POSSIBLE DEPENDING ON SHORT-TERM TRENDS...NEW WATCH ISSUANCE IS NOT
ANTICIPATED.

..DEAN/HART.. 07/26/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LSX...EAX...TOP...ICT...GID...DDC...

LAT...LON   37739938 37730030 37820055 38240072 38779988 39209842
            39439697 39939524 40189320 40079264 39619171 39059183
            38829319 38349476 38099635 37829812 37739938 

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from SPC Mesoscale Discussions http://1.usa.gov/1fvxgeh