andyhb Posted July 5, 2011 Share Posted July 5, 2011 If the GFS plays out, then perhaps the most active day for Southern Manitoba could be Sunday. Link to comment Share on other sites More sharing options...
andyhb Posted July 5, 2011 Share Posted July 5, 2011 Here we go.... ZCZC SPCSWOD48 ALL ACUS48 KWNS 050859 SPC AC 050859 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0359 AM CDT TUE JUL 05 2011 VALID 081200Z - 131200Z ...DISCUSSION... WITH STRONGER WESTERLIES GENERALLY RELEGATED TO THE NORTHERN THIRD OF THE CONUS...00Z ECMWF/GEFS GUIDANCE SUGGEST THAT A CONSIDERABLE UPPER TROUGH WILL SPREAD EASTWARD OVER THE CANADIAN ROCKIES/CENTRAL PRAIRIES AND ADJACENT NORTHERN PLAINS THROUGH DAYS 4-5 FRIDAY/SATURDAY. ON DAY 4/FRIDAY...GIVEN THE EXPECTED EASTWARD PROGRESSION OF THE LARGE SCALE UPPER TROUGH...SURFACE CYCLOGENESIS WILL LIKELY OCCUR ACROSS THE NORTHERN HIGH PLAINS WITH AN INCREASINGLY MOIST AIRMASS IN PLACE AHEAD OF AN ADVANCING COLD FRONT. WITH EXPECTATIONS FOR AMPLE MOISTURE/INSTABILITY AND VERTICAL SHEAR...AN APPRECIABLE/ORGANIZED SEVERE POTENTIAL SEEMS LIKELY TO EXIST ACROSS PORTIONS OF EASTERN MT AND THE DAKOTAS ON DAY 4/FRIDAY. TIED TO THE EASTWARD PROGRESSION OF THE UPPER TROUGH/COLD FRONT...AT LEAST SOME SEVERE THREAT WILL LIKELY CONTINUE INTO DAY 5/SATURDAY ACROSS PORTIONS OF THE UPPER MIDWEST/UPPER MS RIVER VALLEY. A MORE LIMITED PREDICTABILITY PRECLUDES CONSIDERATION OF A 30 PERCENT EQUIVALENT SEVERE RISK AREA DAY 5 AND BEYOND. ..GUYER.. 07/05/2011 Link to comment Share on other sites More sharing options...
Derek30 Posted July 5, 2011 Share Posted July 5, 2011 Saturday probably looks better in my neck of the woods going by recent guidance. Could be some threat on Friday night if some sort of MCS gets going, although that could cause more harm than good for Saturday. Link to comment Share on other sites More sharing options...
andyhb Posted July 5, 2011 Share Posted July 5, 2011 Yeah, that could be a problem, but this still can easily be a multiple day severe threat. GFS has really ramped up that trough since a few days ago. Link to comment Share on other sites More sharing options...
Derek30 Posted July 5, 2011 Share Posted July 5, 2011 GFS has come around to a more impressive set-up. Around my neck of the woods, Saturday is looking more and more like the best threat. Somewhat similar to yesterday honestly. Friday will be a western North Dakota and southeast Saskatchewan/southwest Manitoba show. Hoping for an MCS Fri night. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 5, 2011 Share Posted July 5, 2011 NAM went bonkers on the 18Z--the future progs of that verbatim would be interesting. 18Z operational: Parallel: Link to comment Share on other sites More sharing options...
andyhb Posted July 5, 2011 Share Posted July 5, 2011 It seems like all of the models are coming into relative agreement at this point. Link to comment Share on other sites More sharing options...
Derek30 Posted July 5, 2011 Share Posted July 5, 2011 That's a real impressive vort max on Friday evening/overnight. Would that point to supercells at first with upscale growth into an MCS or even QLCS? Link to comment Share on other sites More sharing options...
andyhb Posted July 5, 2011 Share Posted July 5, 2011 Perfect comma on that trough. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 5, 2011 Share Posted July 5, 2011 It seems like all of the models are coming into relative agreement at this point. It only took the American models about 3 extra days. Link to comment Share on other sites More sharing options...
Stebo Posted July 5, 2011 Share Posted July 5, 2011 NAM went bonkers on the 18Z--the future progs of that verbatim would be interesting. 18Z operational: Parallel: Southern SK/Eastern MT and Western Dakotas looking really good there. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 5, 2011 Share Posted July 5, 2011 Southern SK/Eastern MT and Western Dakotas looking really good there. A bit off topic, but that NAM verbatim would also be a rather significant downslope windstorm for mid summer in the lee of the MT Rockies into the Canadian Rockies in Alberta. Link to comment Share on other sites More sharing options...
wisconsinwx Posted July 5, 2011 Share Posted July 5, 2011 Some scattered showers and storms are headed this way. Although I doubt they'll be severe, this constitutes excitement considering I haven't seen any for awhile. Link to comment Share on other sites More sharing options...
Iastfan112 Posted July 5, 2011 Share Posted July 5, 2011 Under severe thunderstorm warning, measured a 61 mph wind gust but more impressively had .4 inch of rain in a 5 minute span. Just torrents of rain. Edit: Uncle 5 miles north of me lost 4 trees. Link to comment Share on other sites More sharing options...
andyhb Posted July 5, 2011 Share Posted July 5, 2011 Mean-looking tor warned storm north of Des Moines. Link to comment Share on other sites More sharing options...
Stebo Posted July 5, 2011 Share Posted July 5, 2011 SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 558 PM CDT TUE JUL 5 2011 IAC015-187-052315- /O.CON.KDMX.TO.W.0051.000000T0000Z-110705T2315Z/ BOONE IA-WEBSTER IA- 558 PM CDT TUE JUL 5 2011 ...A TORNADO WARNING REMAINS IN EFFECT FOR SOUTH CENTRAL WEBSTER AND NORTHWESTERN BOONE COUNTIES UNTIL 615 PM CDT... AT 556 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED 10 MILES EAST OF GOWRIE...OR 18 MILES SOUTH OF FORT DODGE...MOVING SOUTH AT 25 MPH. LOCATIONS IMPACTED INCLUDE... BOXHOLM...PILOT MOUND AND FRASER. Link to comment Share on other sites More sharing options...
andyhb Posted July 5, 2011 Share Posted July 5, 2011 SEL1 URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 601 NWS STORM PREDICTION CENTER NORMAN OK 610 PM CDT TUE JUL 5 2011 THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF CENTRAL AND SOUTHERN IOWA EFFECTIVE THIS TUESDAY EVENING FROM 610 PM UNTIL 1100 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 55 STATUTE MILES EAST AND WEST OF A LINE FROM 65 MILES NORTH NORTHWEST OF DES MOINES IOWA TO 15 MILES EAST OF LAMONI IOWA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1). 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 600... DISCUSSION...ISOLD SUPERCELL HAS FORMED IN CNTRL IA...ALONG INFLECTION IN BOUNDARY ARCING ESE FROM NEAR SLB TO S OF FOD TO E OF DSM. OTHER STORMS MAY FORM A BIT LATER THIS EVE ALONG THAT PART OF BOUNDARY W OF CURRENT STORM. LOW LVL WIND FIELD IS WEAK. BUT ORIENTATION OF BOUNDARY AND LOW LVL INSTABILITY AXIS...IN CONJUNCTION WITH 40+ KT NWLY 500 MB FLOW...IS RESULTING IN SIGNIFICANT DEVIATE STORM MOTION. COUPLED WITH MOIST LOW LVL ENVIRONMENT...THIS MAY CONTINUE TO SUPPORT EPISODES OF ENHANCED LOW LVL ROTATION AND POSSIBLY A COUPLE TORNADOES GIVEN SUPERCELLULAR NATURE OF STORM/S/. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION VECTOR 34025. ...CORFIDI 40/30 Tornado Probs. Link to comment Share on other sites More sharing options...
SEMIweather Posted July 6, 2011 Share Posted July 6, 2011 Sick dust storm in Phoenix right now...turn on TWC. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 6, 2011 Share Posted July 6, 2011 Really starting to see the potential with this powerful mobile shortwave--especially Saturday. Looks like a good chase day in ND although details are still up in the air. Link to comment Share on other sites More sharing options...
Derek30 Posted July 6, 2011 Share Posted July 6, 2011 Considering a chase west to near the MB/SK border on Friday evening. Good chance of, at least, seeing a solid lightning show. Saturday looks very interesting. GFS seems to bring the front into central ND/southern MB, then push it back west, before finally ejecting it east later in the day. Is this scenario possible or an error on the run? Link to comment Share on other sites More sharing options...
andyhb Posted July 6, 2011 Share Posted July 6, 2011 People around Bismarck best keep their eyes on the sky on Saturday. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 6, 2011 Share Posted July 6, 2011 People around Bismarck best keep their eyes on the sky on Saturday. Friday is going to be active too across western ND and eastern MT. About as an impressive combo of shear (and great low level turning), instability, and frontal convergence combined that you get in that area. Link to comment Share on other sites More sharing options...
andyhb Posted July 6, 2011 Share Posted July 6, 2011 Would you say this is the best setup for severe weather since 6/20 or even 5/25? Edit: 00Z GFS has deepened the trough even further than previously. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 6, 2011 Share Posted July 6, 2011 Would you say this is the best setup for severe weather since 6/20 or even 5/25? Edit: 00Z GFS has deepened the trough even further than previously. Possibly, we still have to wait though because the GFS still treks the upper low a bit too far N on Saturday and it a little weaker than what the NAM would be if it were extrapolated out. I would likely bet that a solution closer to the NAM would be easily the most impressive since the two aforementioned events. Considering the awful handling of the GFS with this system, I am not giving it a ton of consideration. Link to comment Share on other sites More sharing options...
andyhb Posted July 6, 2011 Share Posted July 6, 2011 Day 3: SPC AC 060730 DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0230 AM CDT WED JUL 06 2011 VALID 081200Z - 091200Z ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NORTHERN/CENTRAL HIGH PLAINS... ...NORTHERN/CENTRAL HIGH PLAINS... A CONSIDERABLE UPPER TROUGH IS EXPECTED TO SPREAD EASTWARD FROM THE NORTHERN/CANADIAN ROCKIES TO THE NORTHERN PLAINS/CANADIAN PRAIRIES ON FRIDAY. SURFACE CYCLOGENESIS WILL OCCUR WITH A SHARPENING NORTH-SOUTH LEE TROUGH ACROSS THE HIGH PLAINS...WITH THE SURFACE TROUGH EVENTUALLY BEING OVERTAKEN BY AN EASTWARD ADVANCING COLD FRONT. NEAR/EAST OF THE SURFACE TROUGH/COLD FRONT...A MOIST AIRMASS WILL BE IN PLACE ACROSS FAR EASTERN MT AND THE DAKOTAS/NEB...WITH MIDDLE/UPPER 60S F SURFACE DEWPOINTS LIKELY TO BE PREVALENT IN THESE AREAS BY FRIDAY AFTERNOON. AIDED BY APPRECIABLE LARGE SCALE FORCING FOR ASCENT...TSTMS SHOULD INCREASE IN COVERAGE/VIGOR BY MID/LATE AFTERNOON AND INTO THE EVENING...INITIALLY INCLUDING EASTERN MT TO THE WESTERN DAKOTAS...WITH OTHER MORE ISOLATED SEVERE TSTM DEVELOPMENT SOUTHWARD INTO THE CENTRAL HIGH PLAINS IN VICINITY OF THE LEE TROUGH. ESPECIALLY FROM FAR EASTERN MT TO THE WESTERN/CENTRAL DAKOTAS...AMPLE VERTICAL SHEAR /40-45 KT EFFECTIVE BULK SHEAR/ COINCIDENT WITH A MOIST/MODERATELY UNSTABLE AIRMASS WILL SUPPORT SUPERCELLS CAPABLE OF LARGE HAIL WITH SOME TORNADO RISK AS WELL. ESPECIALLY AS THE COLD FRONT OVERTAKES THE SURFACE TROUGH...STORMS SHOULD CONSOLIDATE/SPREAD EASTWARD THROUGH THE LATE EVENING/OVERNIGHT WITH A RISK OF DAMAGING WINDS/HAIL CONTINUING ACROSS THE DAKOTAS. ...GREAT BASIN TO CO... ISOLATED SEVERE TSTMS CAPABLE OF DOWNBURSTS MAY BE POSSIBLE ACROSS THE EASTERN GREAT BASIN AHEAD OF THE COLD FRONT...WITH OTHER STRONG/SEVERE TSTMS POSSIBLE ACROSS EASTERN CO FRIDAY AFTERNOON/EARLY EVENING. ...SOUTHEAST STATES/CAROLINAS... WHILE THE EXACT DEGREE OF DIURNAL DESTABILIZATION IS UNCERTAIN AT THE DAY 3 JUNCTURE...A GRADUALLY AMPLIFYING EASTERN STATES UPPER TROUGH AND ASSOCIATED MODESTLY STRENGTHENING CYCLONIC FLOW ALOFT MAY AID SEMI-ORGANIZED TSTM DEVELOPMENT ACROSS PORTIONS OF THE SOUTHEAST STATES/CAROLINAS FRIDAY AFTERNOON/EARLY EVENING. REGARDLESS...AT LEAST ISOLATED DOWNBURSTS/SOME SEVERE HAIL WILL BE POSSIBLE WITH THE STRONGEST STORMS. ..GUYER.. 07/06/2011 Link to comment Share on other sites More sharing options...
Derek30 Posted July 6, 2011 Share Posted July 6, 2011 Where would the best threat on Saturday be? Link to comment Share on other sites More sharing options...
andyhb Posted July 6, 2011 Share Posted July 6, 2011 I'm thinking the Eastern Dakotas, Sothern Manitoba and Northern Minnesota. Link to comment Share on other sites More sharing options...
Derek30 Posted July 6, 2011 Share Posted July 6, 2011 Certainly a threat of supercells beginning late Friday afternoon as far east as W ND and SE SK. The activity should push east and, with a decent LLJ, a tornado threat could persist into SW MB and the central Dakotas. Not sure when or if an all out MCS will get going but it could happen overnight, I guess. We'll see how that affects Saturday's threat. If some boundaries are available from the previous night's convection, we could have another long day on our hands. Link to comment Share on other sites More sharing options...
andyhb Posted July 6, 2011 Share Posted July 6, 2011 Forbes already has given a Tor:Con of 5 for West ND Friday. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted July 6, 2011 Share Posted July 6, 2011 Forbes already has given a Tor:Con of 5 for West ND Friday. Friday is shaping up to potentially be the bigger and more impressive day. Saturday is up in the air as the guidance are suggesting the front becomes well displaced from the lagging shortwave. Wind fields are not terribly impressive and the low level flow across the warm sector would yield a mainly unidirectional flow aloft as well as possible capping issues owing to warmer mid levels and weaker low level convergence. Friday right now looks much more impressive than Saturday. Link to comment Share on other sites More sharing options...
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