Nowcasting the Storms… And SPC considers new Tornado Watch

NOWCAST:

The white circle above is where we need to watch for storms that would be tracking into the STC area. I’m not sure if we be watching over towards Stevens County, or down south towards the north end of that line. Tornadoes have been reported with the tornado-warned cells, and 60-70 mph winds with the line of storms to the south. To be honest, I don’t know which one I would rather have move through our neck of the woods. Radar above was taken at about 6:30 — tornado warnings are black, severe thunderstorm warnings yellow.

New Tornado Watch Possible

SPC says that a new tornado watch (or counties added to the current watch) may be possible soon due to that line to the south already reaching the edge of the current watch in effect. The area highlighted includes the rest of the tri county area and the Twin Cities. We will keep you up to date with the latest through the night.

MESOSCALE DISCUSSION 1660
NWS STORM PREDICTION CENTER NORMAN OK
0557 PM CDT THU AUG 12 2010

AREAS AFFECTED…ERN SD…SRN/CNTRL MN

CONCERNING…TORNADO WATCH 603…

VALID 122257Z – 130000Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 603 CONTINUES.

A FEW SUPERCELL STRUCTURES ARE FINALLY STRENGTHENING BENEATH/WITHIN
TRANSITORY BAND OF ELEVATED CONVECTION ALONG THE SD/MN BORDER.
ADDITIONALLY…A FAIRLY FAST MOVING MORE LINEAR STRUCTURE HAS
EVOLVED ALONG THE SRN END OF STRONGER STORMS AND IS EJECTING NEWD AT
ROUGHLY 45KT ACROSS SWRN MN…NEARING THE ERN EDGE OF WW603.
CURRENT SPEED/MOVEMENT SUGGESTS SEVERE THREAT WILL SPREAD INTO CNTRL
MN ULTIMATELY NECESSITATING THE NEED TO EITHER EXPAND THE CURRENT
WW…OR ISSUE ANOTHER TORNADO WATCH SHORTLY.

..DARROW.. 08/12/2010

ATTN…WFO…DLH…MPX…FGF…FSD…ABR…

LAT…LON 46249606 46049280 44869228 44139340 43799569 44849621
45589687 46249606

SPC: Highest tornado threat in the STC area next few hours…

Need to watch for tornadoes within the next few hours… remember nighttime tornadoes can be even more dangerous than day time ones, as you cannot see them coming your way. This is not time for amateur chasing hour!

MESOSCALE DISCUSSION 1608
NWS STORM PREDICTION CENTER NORMAN OK
0857 PM CDT SAT AUG 07 2010

AREAS AFFECTED…CNTRL/NRN MN AND WCNTRL/NWRN WI

CONCERNING…TORNADO WATCH 584…

VALID 080157Z – 080330Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 584 CONTINUES.

01Z SURFACE ANALYSIS PLACES A WARM FRONT JUST N OF THE I-94 CORRIDOR
FROM WCNTRL MN SEWD INTO WCNTRL WI. SUPERCELL STORMS THAT INITIATED
BEFORE SUNSET SW OF FERGUS FALLS HAVE UNDERGONE NUMEROUS CELL SPLITS
WITH A LONG-LIVED SURFACE BASED RIGHT-MOVING CELL BEING MAINTAINED
ALONG I-94 NW OF ALEXANDRIA. LEFT-SPLITS HAVE MOVED NE INTO NCNTRL
MN…ALONG/N OF THE WARM FRONT WHILE ADDITIONAL STORMS CONTINUE TO
FORM DOWNSTREAM ALONG THE SAME FRONT TOWARD NWRN WI. THE LATTER
PROCESS WILL LIKELY CONTINUE INTO NRN/CNTRL WI DURING THE NEXT
SEVERAL HOURS AS THE SWLY LLJ BECOMES FOCUSED INTO CNTRL MN. WHILE
LARGE HAIL WILL BE THE PRIMARY RISK WITH THESE STORMS…DAMAGING
WINDS CANNOT BE RULED OUT. NEW WW/S MAY BE NEEDED DOWNSTREAM SOON.

MEANWHILE…THE HIGHEST TORNADO POTENTIAL WILL BE ASSOCIATED WITH
STORMS ALONG THE I-94 CORRIDOR FROM ALEXANDRIA-WADENA SEWD TOWARD
THE MSP METRO AREA THROUGH 06Z. HERE…STORMS WILL LIKELY REMAIN
SURFACE-BASED AND TAP 2500-3000 J/KG MLCAPE AND NEAR 175 M2/S2 0-1KM
SRH. ADDITIONALLY…LARGE HAIL CAN BE EXPECTED.

..RACY.. 08/08/2010

ATTN…WFO…GRB…DLH…ARX…MPX…FGF…ABR…

LAT…LON 48269841 47089405 45839154 45018945 44198979 44159144
44319285 44309298 46109787 48269841

SPC: Timing Uncertain, But Watch Will Be Needed… Possibly In Next Couple Hours?

Gotta love the Storm Prediction Center, who basically just stated that they are gonna wing it when it comes to putting out a watch for areas mainly west of the STC area. They state that a watch will be needed, but it is unknown when they might have to issue it *sigh*. The main threats will be large hail, short-lived tornadoes, and damaging winds/downbursts. I’d expect a watch myself to be issued closer to 5 pm for this area — whether it is a Tornado or Severe Thunderstorm Watch will depend on how big they think the tornado threat is. If it is a Severe Thunderstorm Watch, I would expect a larger watch box that will encompass a good chunk of southern MN through the middle of the night.

I could be wrong though…

MESOSCALE DISCUSSION 1604
NWS STORM PREDICTION CENTER NORMAN OK
0310 PM CDT SAT AUG 07 2010

AREAS AFFECTED…SERN NORTH DAKOTA…NERN SOUTH DAKOTA…W CNTRL MN

CONCERNING…SEVERE POTENTIAL…WATCH LIKELY

VALID 072010Z – 072215Z

TIMING IS STILL SOMEWHAT UNCERTAIN…BUT A WATCH WILL LIKELY BE
NEEDED AT SOME POINT LATE THIS AFTERNOON…PERHAPS WITHIN THE NEXT
HOUR OR TWO.

STRONGEST LOW-LEVEL CONVERGENCE AND WARM ADVECTION APPEAR FOCUSED IN
A ZONE EAST SOUTHEAST OF A WEAK SURFACE LOW…NEAR JAMESTOWN ND INTO
THE DETROIT LAKES/ALEXANDRIA AREAS OF WEST CENTRAL MINNESOTA. THIS
IS WHERE SURFACE HEATING OF A MOIST BOUNDARY LAYER WITH DEW POINTS
NEAR 70F HAS ALREADY CONTRIBUTED TO CAPE IN EXCESS OF 3000 J/KG IN
THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES. WITH ADDITIONAL
HEATING…AND THE APPROACH OF AN AREA OF ENHANCED MID-LEVEL FORCING
FOR UPWARD VERTICAL MOTION…NOW SPREADING EASTWARD ACROSS CENTRAL
NORTH DAKOTA…VIGOROUS CONVECTIVE DEVELOPMENT IS EXPECTED LATE THIS
AFTERNOON.

BASED LARGELY ON MODEL GUIDANCE…THIS SEEMS PROBABLE BY 21-23Z.
INITIAL ACTIVITY APPEARS LIKELY TO BE DISCRETE…AND PROBABLY WILL
REMAIN SO FOR AT LEAST A FEW HOURS…AS IT PROPAGATES EAST
SOUTHEASTWARD IN THE PRESENCE OF A STRONGLY SHEARED 30 KT WESTERLY
DEEP LAYER MEAN FLOW. UNTIL FORCING ON THE NOSE OF A STRENGTHENING
SOUTHWESTERLY 850 MB JET COMES IN PHASE WITH STRONGER
CONVECTION…AND SUPPORTS UPSCALE CONVECTIVE GROWTH… ISOLATED
SUPERCELLS WILL BE POSSIBLE…ACCOMPANIED BY LARGE HAIL…THE THREAT
FOR GENERALLY SHORT-LIVED TORNADOES…AND PERHAPS LOCALLY DAMAGING
DOWNBURSTS.

..KERR.. 08/07/2010

ATTN…WFO…MPX…FGF…ABR…BIS…

LAT…LON 46859892 47059837 47409741 46969589 46089523 45539594
45429644 46079817 46449881 46859892

SPC: Environment Still Capable For Storms… DJ: We Shall See About That…

Ah, I had a feeling the SPC would shoot and be wrong when they put out that Tornado Watch… I just didn’t have the feeling that it would happen (and look at this… I’ve been right so far!!!). The SPC says that some development is still possible within the next few hours before storms move into the watch box area from the south and west around the time the watch box is expected to expire. I say… We shall see. We’ll keep an eye on the radar for any of this development… but I was skeptical of the set up when I woke up this morning for severe development, and still am for our area until maybe later tonight if we can get a system rolling to our west. Maybe the SPC will get lucky and get it right… but when they are already eliminating part of the Tornado Watch to our west and replacing it with a Severe Tstorm Watch until midnight… just makes me believe even more that all bets are off with the SPC’s forecast today! When my gut is correct more often than the SPC (like it was last year I believe) — something is seriously wrong!

MESOSCALE DISCUSSION 1535
NWS STORM PREDICTION CENTER NORMAN OK
0656 PM CDT SUN AUG 01 2010

AREAS AFFECTED…PORTIONS NERN SD AND CENTRAL/WRN MN.

CONCERNING…TORNADO WATCH 558…

VALID 012356Z – 020200Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 558 CONTINUES.

EARLIER SVR TSTMS THAT FORMED OVER NERN SD AND MOVED INTO MN HAVE
WEAKENED OVER RELATIVELY STABLE AIR MASS N OF QUASISTATIONARY
OUTFLOW/DIFFERENTIAL HEATING BOUNDARY…WHICH WAS ANALYZED AT 23Z
FROM MCLEOD COUNTY MN WNWWD ACROSS ROBERTS COUNTY SD. THIS BOUNDARY
INTERSECTS FRONTAL ZONE OVER ROBERTS OR MARSHALL COUNTY SD.
REFLECTIVITY ANIMATIONS SHOW FRONTAL BOUNDARY FROM MARSHALL COUNTY
SD WSWWD INTO POTTER COUNTY…QUASISTATIONARY EXCEPT INVOF ATTACHED
MISOSCALE CIRCULATION OVER CENTRAL EDMUNDS COUNTY. THIS BOUNDARY
THEN EXTENDS SWWD THROUGH LOW NEAR PIR…AND INTO NWRN NEB.
CONVERGENCE ON EITHER BOUNDARY…ESPECIALLY IN AND E OF MISOLOW AND
NEAR THEIR INTERSECTION…MAY CONTRIBUTE TO POTENTIAL FOR ADDITIONAL
CONVECTIVE DEVELOPMENT IN NEXT 1-2 HOURS…IN ENVIRONMENT STILL
FAVORABLE FOR SUPERCELLS. MODIFIED RAOBS AND RUC SOUNDINGS INDICATE
MINIMAL MLCINH FROM THIS AREA ESEWD ALONG MN BOUNDARY…WITH MLCAPE
2000-3500 J/KG AND 40-45 KT EFFECTIVE SHEAR MAGNITUDES. OTHER TSTMS
OVER WW 560 MAY MOVE NEWD INTO SWRN PORTIONS OF THIS WW WITHIN NEXT
2-3 HOURS AS WELL.

..EDWARDS.. 08/01/2010

ATTN…WFO…DLH…MPX…FGF…FSD…ABR…BIS…

LAT…LON 44429461 44599794 45219801 45219917 45479918 46489716
46549505 45639346 44429461

SPC: Tornado Watch Likely Soon

SPC says a Tornado Watch is likely soon in an area from Little Falls to the Twin Cities north-southward and from the bulge in west central MN to western WI west-eastward.

MESOSCALE DISCUSSION 1476
NWS STORM PREDICTION CENTER NORMAN OK
0143 PM CDT TUE JUL 27 2010

AREAS AFFECTED…CENTRAL MN AND PART OF WRN/NWRN WI

CONCERNING…SEVERE POTENTIAL…TORNADO WATCH LIKELY

VALID 271843Z – 271915Z

TORNADO WATCH WILL BE COORDINATED SOON ACROSS MUCH OF CENTRAL MN
INTO PART OF WRN/NWRN WI.

EARLY AFTERNOON MESOANALYSES SHOWED A COLD FRONT ADVANCING EWD
ACROSS THE DAKOTAS INTO NWRN MN…WITH THIS FRONT INTERSECTING A
WNW-ESE ORIENTED WARM FRONT AND RETREATING OUTFLOW BOUNDARY OVER
SERN ND/ NERN SD. VISIBLE SATELLITE IMAGERY INDICATED HIGH LEVEL
CLOUDS ATTENDANT TO MORNING MCS HAVE DISSIPATED ACROSS CENTRAL MN
INTO WRN WI ALLOWING FOR STRONGER SURFACE HEATING WITH TEMPERATURES
CLIMBING THROUGH THE UPPER 80S TO AROUND 90 F FROM CENTRAL MN INTO
ERN SD. THIS COMBINED WITH RICH BOUNDARY LAYER MOISTURE /SURFACE
DEWPOINTS IN THE LOWER-MID 70S/ HAVE SUPPORTED MLCAPE UP TO
2500-3000 J/KG SO FAR.

SPECIAL 18Z MPX SOUNDING SHOWED WARMING HAS OCCURRED IN THE 850-500
MB LAYER…WITH ADDITIONAL SURFACE HEATING NEEDED TO WEAKEN THE
REMAINING SURFACE BASED INHIBITION. VISIBLE IMAGERY SHOWED CU
FORMING OVER FAR NERN SD IN THE VICINITY OF PERSISTENT LOW LEVEL
CONVERGENCE AT THE TRIPLE POINT/SUB-SYNOPTIC SURFACE LOW.
HOWEVER…INHIBITION IS STRONGER WITH WWD EXTENT PER OBJECTIVE
ANALYSES.

REGIONAL RADAR IMAGERY SHOWED NEW TSTMS DEVELOPING N OF THE WARM
FRONT IN SERN ND AS STRONGER FORCING FOR ASCENT WITH THE EWD MOVING
UPPER TROUGH AND ALONG THE COLD FRONT SPREAD INTO THIS REGION. THIS
ACTIVITY IS LIKELY ELEVATED AND MAY PRODUCE MAINLY A HAIL THREAT.
MEANWHILE…CONSECUTIVE RUNS OF THE WRF-HRRR SUGGEST SURFACE BASED
STORMS WILL DEVELOP BETWEEN 19-20Z OVER WEST CENTRAL MN. THIS
SCENARIO APPEARS LIKELY GIVEN ADDITIONAL SURFACE HEATING AND AN
INCREASE IN DEEP LAYER ASCENT SPREADING EWD INTO A REGION OF LOW
LEVEL CONVERGENCE ALONG THE WARM FRONT. GIVEN VERY STRONG
INSTABILITY EXTENDING EWD ACROSS CENTRAL MN INTO WRN WI AND
STRENGTHENING DEEP LAYER SHEAR…STORMS SHOULD QUICKLY BECOME SEVERE
ONCE THEY DEVELOP INTO CENTRAL MN. S/SELY SURFACE WINDS BENEATH A
STRENGTHENING SWLY LLJ WILL SUPPORT AN INCREASE IN HODOGRAPH
CURVATURE AND AN INCREASED POTENTIAL FOR TORNADOES.

..PETERS.. 07/27/2010

Severe/Tornado Threat out west, north for next couple hours

We were under a severe risk… then not… then we get severe weather today? Grr SPC — this is as bad as last summer!… anyway, Tornado Warnings have been issued up north and west for storms forming. The Storm Prediction Center does not anticipate issuing a watch as the severity of these storms is not expected to last more than a couple hours. The storms are expected to stay north of the STC area.

MESOSCALE DISCUSSION 1420
NWS STORM PREDICTION CENTER NORMAN OK
0614 PM CDT THU JUL 22 2010

AREAS AFFECTED…WEST-CENTRAL/NORTH-CENTRAL MN

CONCERNING…SEVERE POTENTIAL…WATCH UNLIKELY

VALID 222314Z – 230045Z

A SHORT TERM SEVERE/TORNADO THREAT WILL EXIST THROUGH PERHAPS AROUND
01Z-02Z ACROSS PORTIONS OF WEST-CENTRAL/NORTH-CENTRAL MN. A WATCH IS
NOT CURRENTLY ANTICIPATED GIVEN THE EXPECTED SHORT TERM NATURE OF
THE SEVERE THREAT.

STORMS HAVE INCREASED WITHIN A NNE-SSW ORIENTED CORRIDOR IN VICINITY
OF A WEAK SURFACE FRONT/TROUGH…ON THE SOUTHERN PERIPHERY OF A
SHORTWAVE TROUGH/ASSOCIATED MID LEVEL SPEED MAX ACROSS ND/SOUTHERN
MANITOBA. WHILE APPRECIABLE SURFACE BASED DESTABILIZATION HAS BEEN
HINDERED BY CLOUD COVER…A RELATIVELY MOIST AIRMASS AND MODEST
DESTABILIZATION WITH AROUND 500-750 J/KG MLCAPE…IN CONJUNCTION
WITH A FAVORABLE LOW LEVEL/DEEP LAYER SHEAR ENVIRONMENT…WILL
SUPPORT ROTATING STORMS CAPABLE OF BRIEF TORNADOES AND PERHAPS
SEVERE HAIL/GUSTY WINDS OVER THE NEXT FEW HOURS. THE BRUNT OF THIS
THREAT SHOULD WANE AROUND/SOON AFTER SUNSET AS THE BOUNDARY LAYER
BEGINS TO DECOUPLE.

..GUYER.. 07/22/2010

ATTN…WFO…DLH…MPX…FGF…ABR…

LAT…LON 48119529 48529343 45469540 45839666 48119529

SPC: Tornado Threat Should Increase Over Western MN In Next Few Hours

A new Mesoscale Discussion from the Storm Prediction Center says that the tornado threat is likely to increase within the next few hours as storms move into western Minnesota. The right ingredients are coming together once again and could cause another round of very large hail and tornadoes across western MN. Will update you as needed as the storms move through.

New Watch (Tornado?) Expected Soon

The Storm Prediction Center has issued a Mesoscale Discussion saying that, even though it is likely, a new weather watch should be issued soon. I think they may go ahead and place a tornado watch out for the southern portion of the state and stay ahead of the storms later this afternoon — but they could do anything. Will update when we get a watch.

MESOSCALE DISCUSSION 1297
NWS STORM PREDICTION CENTER NORMAN OK
0826 AM CDT WED JUL 14 2010

AREAS AFFECTED…PARTS OF SRN THROUGH CNTRL MN AND NRN WI

CONCERNING…SEVERE POTENTIAL…WATCH LIKELY

VALID 141326Z – 141430Z

TORNADO WATCH 471 WILL NEED TO BE REPLACED BY ANOTHER WW SOON.

MCS IS EXPECTED TO CONTINUE EWD THROUGH PARTS OF NRN WI. OTHER
STORMS MAY DEVELOP SOUTH OF THE MCS AND EVENTUALLY BECOME SURFACE
BASED WITHIN THE ZONE OF LOW LEVEL WARM ADVECTION IN VICINITY OF THE
WARM FRONT FROM SRN MN EWD INTO THE NRN HALF OF WI.

..DIAL.. 07/14/2010

ATTN…WFO…GRB…DLH…ARX…MPX…

SPC says Tornado Watch possible soon just to the west

The Storm Prediction Center is monitoring western MN, including into Stearns County, for the possibility of another watch being issued. They strongly word that the conditions are becoming favorable for a few tornadoes, and that because of this they may have to issue a Tornado Watch once things get started. Will continue to monitor as this may turn out to be a busier night than first thought…

MESOSCALE DISCUSSION 1239
NWS STORM PREDICTION CENTER NORMAN OK
0403 PM CDT SAT JUL 10 2010

AREAS AFFECTED…EASTERN SD/SOUTHEAST ND AND WEST CENTRAL/SOUTHWEST
MN

CONCERNING…SEVERE POTENTIAL…WATCH POSSIBLE

VALID 102103Z – 102230Z

MONITORING FOR AN INCREASING SURFACE BASED SEVERE THREAT…INCLUDING
LARGE HAIL/TORNADO POTENTIAL…ACROSS EASTERN SD/SOUTHEAST ND INTO
WEST-CENTRAL/SOUTHWEST MN.

SHORTWAVE RIDGING APPEARS TO BE CURRENTLY OCCURRING ACROSS THIS
VICINITY…IN THE WAKE OF THE EARLY DAY SHORTWAVE TROUGH NOW
ENTERING WESTERN WI…AND AHEAD OF AN EASTWARD ADVANCING SHORTWAVE
TROUGH NOW OVER FAR EASTERN WY. WITH THAT SAID…A RELATIVELY
VOLATILE AIRMASS/SCENARIO POTENTIALLY EXISTS FROM EASTERN SD INTO
SOUTHEAST ND AND WESTERN/SOUTHWEST MN. SURFACE DEWPOINTS TO NEAR
70F…BENEATH A STRENGTHENING ELEVATED MIXED PLUME…ARE YIELDING
WEAK INHIBITION WITH MLCAPE VALUES TO 3000-4000 J/KG. WHILE THE
LARGE SCALE SUPPORT IS NOT PARTICULARLY FAVORABLE AS PREVIOUSLY
MENTIONED…A TREND TOWARD INCREASING NEAR-SURFACE CONVERGENCE HAS
NOT NOTED OVER THE PAST 1-2 HOURS NEAR THE ND/SD/MN BORDER
VICINITY…WHERE AN INCREASE IN BOUNDARY LAYER CU IS EVIDENT IN
VISIBLE SATELLITE IMAGERY. THIS CONVERGENCE IS AIDED BY A RELATIVE
MAXIMA OF SURFACE PRESSURE FALLS…WITH A PSEUDO/WEAK TRIPLE POINT
NEAR THE INTERSECTION OF A SURFACE PRE-COLD FRONTAL TROUGH AND AN
EARLY DAY RAIN-COOLED/WEAK EFFECTIVE WARM FRONT THAT IS ROUGHLY
ORIENTED WNW-ESE ACROSS WEST-CENTRAL/SOUTHWEST MN. THE WOOD LAKE MN
WIND PROFILER SAMPLES THE STRONGLY VEERING WIND PROFILES THAT
CURRENTLY EXIST ACROSS THIS CORRIDOR…WITH EFFECTIVE BULK SHEAR OF
30-35 KT AND SUFFICIENT LOW LEVEL HODOGRAPH CURVATURE WHICH IS
CONDITIONALLY FAVORABLE FOR SUPERCELLS CAPABLE OF TORNADOES. IN
ALL…CLOSELY MONITORING FOR INCREASING SURFACE BASED SEVERE TSTM
POTENTIAL INCLUDING A TORNADO RISK…AND INCREASING CONFIDENCE IN
SURFACE BASED DEEP CONVECTIVE INITIATION MAY PROMPT A TORNADO WATCH
ISSUANCE.

..GUYER.. 07/10/2010

ATTN…WFO…MPX…FGF…FSD…ABR…

LAT…LON 43719848 46799607 46599495 45719447 44599490 43929627
43719848

Watch Likely For West Central MN By 3 PM

UPDATE 320 PM: The SPC did end up putting a Severe Thunderstorm Watch out, but it stayed strictly in South Dakota and did not stretch into Minnesota.