weathergy Posted February 24, 2012 Share Posted February 24, 2012 000FXUS63 KDTX 240247 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 947 PM EST THU FEB 23 2012 .UPDATE... IN THE VERY SHORT TERM, NO CHANGES ARE EXPECTED IN THE TIMING OR COVERAGE OF HEADLINES. FORECAST ADJUSTMENTS WILL ADD A MIX OF SLEET TO THE ACTIVITY NEAR THE OHIO BORDER UP TO ABOUT DETROIT DURING THE NEXT 3 TO 6 HOURS. IN THE LONGER TERM, NORTHWARD ADJUSTMENTS TO THE PLACEMENT OF HEAVIEST SNOW ACCUMULATION MAY BE NEEDED, BRINGING THE TRI CITIES CLOSER TO A POTENTIAL WARNING HEADLINE RATHER THAN AN ADVISORY. CONVECTION INCREASING IN COVERAGE AND INTENSITY OVER NORTHERN INDIANA AND OHIO AT PRESS TIME IS EXPECTED TO DEVELOP WESTWARD TOWARD THE INFLUENCE OF THE STRONG MID LEVEL SHORT WAVE INDICATED IN SATELLITE IMAGERY MOVING IN FROM IOWA. THIS WAVE WILL INDUCE INTENSE SECONDARY SURFACE CYCLOGENESIS OVER INDIANA WHICH WILL HOLD THE LOW LEVEL JET IN PLACE OVER LOWER MICHIGAN AND SUPPORT STRONG SYSTEM RELATIVE ISENTROPIC ASCENT THROUGH HIGHER ELEVATIONS OF THE FRONTAL ZONE. WITH SPECIFIC HUMIDITY ON THE 290K ISENTROPIC SURFACE APPROACHING 4 G/KG, THE RESULT WILL BE CONTINUED NORTHWARD EXPANSION AND INTENSIFICATION OF THE PRECIPITATION PATTERN INTO THE EARLY OVERNIGHT HOURS ASSOCIATED WITH THE INTENSE MOISTURE TRANSPORT AND RESULTING DESTABILIZATION. ANY REMAINING MIX OF RAIN, SLEET, AND SNOW WILL BE FORCED OVER TO ALL SNOW BY THE COOLING EFFECT OF HIGHER PRECIPITATION RATES. EVIDENCE OF THIS IS ALREADY APPEARING UPSTREAM CLOSER TO THE NORTH FLANK OF THE SURFACE LOW. THE ABOVE REFERENCED MODE OF FORCING WILL DOMINATE THE FIRST THIRD OF THE EVENT WITH ABOUT 1 TO 3 INCHES OF SNOW EXPECTED TO RESULT THROUGH 3 OR 4 AM, MAINLY SOUTH OF INTERSTATE 69, AS THE LOW PRESSURE SYSTEM APPROACHES THE REGION. AS THE SYSTEM MOVES BY TO OUR SOUTH AND EAST, ISENTROPIC ASCENT WILL TRANSITION TO A CONSIDERABLY MORE DYNAMIC TROWAL PATTERN CAPABLE OF EVEN MORE INTENSE RATES OF SNOWFALL. THIS IS EXPECTED TO BE THE BULK OF THE REMAINING EVENT THAT WILL LAST FROM LATER IN THE NIGHT THROUGH MID TO LATE FRIDAY MORNING AND WILL BRING THE LARGEST CONTRIBUTION TO SNOWFALL TOTALS. UNFORTUNATELY, THAT MEANS THE PEAK OF THE EVENT WILL BE ONGOING THROUGH THE FRIDAY MORNING TRAVEL PERIOD. THIS IS ALSO THE MOST DIFFICULT PART OF THE FORECAST IN TERMS OF IDENTIFYING THE PLACEMENT OF THE MOST INTENSE BAND AND POTENTIAL IMPACTS OF THE DRY SLOT MAKING A RUN INTO THE DETROIT AREA BY SUNRISE. INCOMING 00Z MODEL DATA SUPPORTS THE TROWAL AXIS SETTING UP A LITTLE FARTHER NORTH, ROUGHLY ALONG A LINE FROM LANSING TO BAD AXE, WITH A SHARP GRADIENT IN ACCUMULATION SOUTHWARD THROUGH DETROIT TO THE OHIO BORDER. EXPECTING THE MOST INTENSE MESOSCALE BAND TO SET UP ROUGHLY BETWEEN THE TROWAL AXIS AND THE LEADING EDGE OF THE DRY SLOT THAT MARKS WHERE CONVECTIVE INSTABILITY WILL BE MAXIMIZED, OR ROUGHLY ALONG A LINE FROM HOWELL TO LAPEER TO PORT SANILAC. && Link to comment Share on other sites More sharing options...
A-L-E-K Posted February 24, 2012 Share Posted February 24, 2012 worth noting that his res/ruc/hrrr runs all day didn't get going until 4-6z around here. Link to comment Share on other sites More sharing options...
QVectorman Posted February 24, 2012 Share Posted February 24, 2012 Should get interesting between 11pm - 2am. Could be quick 2" Yup! I mean the models weren't forecasting the best dynamics to develop until then anyways. I didn't expect much out of this anyways but people have to realize this is forecasting! Over a decade ago when I was at PSU I had Fritsch and he always made us forecast events that were to evolve rather than already developing and on the move. Makes you a lot better forecaster. No need for weenie suicide. The best is yet to come tonight Link to comment Share on other sites More sharing options...
Geos Posted February 24, 2012 Share Posted February 24, 2012 From Skilling via. Facebook: Quick update as we prepare for the 9PM show. More than 2" of wet snow is down across some north suburbs---Forreston & Wadsworth have both reported 2.2"--while rain is mixing with ice pellets OakBrook and in the I-88 corridor. The storm's maximum lift, where dynamic cooling will take rain over to snow, is entering western Illinois near the Quad Cities. There there's been noticeable enhancement of precip echoes there are radar and that region will continue eastward across northern Illinois. This lift is occurring under the nose of a 110 mph jet stream wind max. Sections of Iowa under the the nose of this speed max in Iowa and South Dakota have recorded 6-10" of snow under this speed max during the day--a guide to this system's potential. The liquid or mixed precip will transition from north to south to snow here and snow intensities will pick up. We may even see embedded thunderstorms. This strong lift is to continue into the morning rush hour. It's during this period the system's main accumulation is expected. We think widespread 5 to 7" totals--lighter southern sections where the change to all snow may wait until the wee hours of the morning--- are likely. We're bracketing area snowfall from 4 to 9". Link to comment Share on other sites More sharing options...
huronicane Posted February 24, 2012 Share Posted February 24, 2012 02z update from Izzi: //DISCUSSION...UPDATED 02Z...SITUATION EVOLVING MORE SLOWLY THAN EARLIER ANTICIPATED AND HAVE ONCE AGAIN DELAYED THE ONSET OF STEADIER SNOWFALL. RADAR/SATELLITE TRENDS SHOW CONVECTIVEY ELEMENTS CONTINUING TO POP UP FROM CHGO METRO SW TO UIN AREA...WITH REPORTS OF RA/SN/GS BEING RECEIVED WITH THESE SHOWERS. UNTIL STEADIER HEAVIER DEFORMATION BAND DEVELOPS OVER THE AREA AFTER MIDNIGHT...WOULD EXPECT TO CONTINUE TO SEE OCNL SHRASNGS WITH PERIODIC DZ OUTSIDE OF THE SHOWERS. STARTING TO SEE A MORE ORGANIZED FRONTOGENETIC BAND DEVELOP NEAR THE QUAD CITIES INTO NW IL AND WOULD ANTICIPATE THIS BAND TO GROW IN AREAL COVERAGE AND DEVELOP EAST TONIGHT...EVENTUALLY REACHING CHICAGO METRO AREA AFTER MIDNIGHT. STILL ANTICIPATE A 4-6 HOUR LONG PERIOD OF MODERATE TO HEAVY SNOW FOR CHICAGO...THOUGH NOW APPEARS AS THOUGH THE MORE LIKELY TIMING IS LATE TONIGHT/EARLY FRIDAY MORNING. IZZI Link to comment Share on other sites More sharing options...
hawkeye_wx Posted February 24, 2012 Share Posted February 24, 2012 New 5.5 inch report from Independence, IA... just east of Waterloo. The guy reported 2 inches in the last hour with huge flakes. Still a mix of light rain and very light snow here. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 24, 2012 Share Posted February 24, 2012 Yup! I mean the models weren't forecasting the best dynamics to develop until then anyways. I didn't expect much out of this anyways but people have to realize this is forecasting! Over a decade ago when I was at PSU I had Fritsch and he always made us forecast events that were to evolve rather than already developing and on the move. Makes you a lot better forecaster. No need for weenie suicide. The best is yet to come tonight Just curious where are you located? Link to comment Share on other sites More sharing options...
hm8 Posted February 24, 2012 Share Posted February 24, 2012 That's a great read from DTX. Watching the Wings game and following this storm at the same time is too much, I'm gonna crack Link to comment Share on other sites More sharing options...
SpartyOn Posted February 24, 2012 Share Posted February 24, 2012 I see Baro is about to post.. Breathing some common sense into equation. Link to comment Share on other sites More sharing options...
QVectorman Posted February 24, 2012 Share Posted February 24, 2012 Just curious where are you located? Originally from the Ann Arbor area of Michigan but live in Atlanta Link to comment Share on other sites More sharing options...
turtlehurricane Posted February 24, 2012 Share Posted February 24, 2012 Axis of band has stalled out just south of here, moderate to maybe heavy snow continues across downtown Madison. 0.07" liquid thus far and roads getting covered. Everything else already has a nice coat of wet snow. Link to comment Share on other sites More sharing options...
indeedinger Posted February 24, 2012 Share Posted February 24, 2012 New 5.5 inch report from Independence, IA... just east of Waterloo. The guy reported 2 inches in the last hour with huge flakes. Still a mix of light rain and very light snow here. That guy would be me. Crazy snow here. Sorry you aren't in on the fun. Link to comment Share on other sites More sharing options...
QVectorman Posted February 24, 2012 Share Posted February 24, 2012 Looks like everyone is reporting snow across S. Mich including Toledo! Let the games begin! Link to comment Share on other sites More sharing options...
cyclone77 Posted February 24, 2012 Share Posted February 24, 2012 Back to light rain/sleet here. Link to comment Share on other sites More sharing options...
dmc76 Posted February 24, 2012 Share Posted February 24, 2012 Temps in the 34-36 Range.. gotta get this sucker down as moisture moves in Link to comment Share on other sites More sharing options...
huronicane Posted February 24, 2012 Share Posted February 24, 2012 Heavy Snow MD out from SPC: http://www.spc.noaa.gov/products/md/md0147.html Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 24, 2012 Author Share Posted February 24, 2012 MESOSCALE DISCUSSION 0147 NWS STORM PREDICTION CENTER NORMAN OK 0845 PM CST THU FEB 23 2012 AREAS AFFECTED...SRN IA...NRN IL...SRN WI CONCERNING...HEAVY SNOW VALID 240245Z - 240745Z A BAND OF SNOWFALL...ASSOCIATED WITH A NEGATIVELY TILTED SHORTWAVE TROUGH AND ATTENDANT SFC LOW...WILL RESULT IN BRIEF PERIODS OF MOD TO HVY SNOW ACROSS THE UPPER MIDWEST. A NEGATIVELY TILTED SHORTWAVE WILL CONTINUE TO PROGRESS EWD ACROSS THE MIDWEST DURING THE NEXT FEW HOURS. SFC LOW ASSOCIATED WITH THIS SHORTWAVE IS CURRENTLY CENTERED OVER S IL AND FAR W KY. 850 MB FRONTOGENESIS AND ITS ASSOCIATED SNOW BAND... CURRENTLY LOCATED ACROSS SRN IA EWD TO SRN MI...IS EXPECTED TO DRIFT SWD AND WEAKEN OVER THE NEXT FEW HOURS AS THE SHORTWAVE TROUGH AND SFC LOW PROGRESS EWD. A SATURATED DENDRITIC GROWTH ZONE AND EASTERLY FLOW BTW 925-850 MB SHOULD CONTINUE TO PROMOTE BRIEF PERIODS OF MOD TO HVY SNOW WITHIN THE BAND. HOWEVER..WEAKENING FRONTOGENESIS WITH TIME WILL RESULT IN A GRADUAL REDUCTION IN SNOWFALL RATES ACROSS IA. FURTHER E...THE POTENTIAL FOR HIGHER RATES WILL LINGER FOR THE NEXT SEVERAL HOURS. ADDITIONALLY...QUICK PROGRESSION OF THE SYSTEM SHOULD LIMIT OVERALL SNOWFALL TOTALS. ..MOSIER/LEITMAN.. 02/24/2012 Link to comment Share on other sites More sharing options...
Geos Posted February 24, 2012 Share Posted February 24, 2012 Axis of band has stalled out just south of here, moderate to maybe heavy snow continues across downtown Madison. 0.07" liquid thus far and roads getting covered. Everything else already has a nice coat of wet snow. You are under an advisory now.! Link to comment Share on other sites More sharing options...
michsnowfreak Posted February 24, 2012 Share Posted February 24, 2012 Back to light rain/sleet here. Sorry to hear that. You are overdue for some snow....you have been going back and forth all day it seems. I dont get this storm much like I dont get this winter lol. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 24, 2012 Author Share Posted February 24, 2012 LOT NO CHANGES TO GOING ADVISORY HEADLINES THIS EVENING. HOWEVER... FORECAST REMAINS QUITE COMPLEX WITH RESPECT TO SNOW AMOUNTS AND PRECIP TYPES THROUGH THE EARLY OVERNIGHT HOURS. EVENING VAPOR IMAGERY SHOWS STRONG SHORT WAVE TROUGH DIGGING EAST-SOUTHEAST ACROSS IA/MO. MAIN SFC LOW WAS OVER SOUTHERN INDIANA WITH TROUGH TRAILING BACK THROUGH WESTERN IL/SOUTHERN IA. INITIAL PUSH OF WARM ADVECTION RAIN/SNOW HAD GENERALLY LIFTED TO/NORTH OF THE WI BORDER DURING THE EVENING HOURS...WHILE FARTHER TO THE WEST REGIONAL RADAR MOSAIC DEPICTED EXTENSION OF BROAD DEVELOPING DEFORMATION BAND FROM SOUTHWEST IA INTO SOUTHERN WI. EVIDENCE OF FRONTOGENETICALLY FORCED ENHANCED PRECIPITATION WAS NOTED ACROSS FAR EASTERN IA...JUST NORTH OF THE QUAD CITIES. MUCH OF THE CWA HAS SEEN A LULL IN MORE ORGANIZED MEASURABLE PRECIP DURING THE EVENING HOURS. 22-23Z RUNS OF THE HRRR SEEM TO HAVE A VERY GOOD HANDLE ON TRENDS ACROSS THE REGION THROUGH MID-EVENING... AND WOULD SUGGEST DEFORMATION PRECIP AXIS WILL GRADUALLY TRANSLATE EAST ACROSS THE AREA DURING THE OVERNIGHT/FRIDAY MORNING HOURS. WHILE THE CURRENT BAND NEAR DVN IS IMPRESSIVE LOOKING...HIGH RES SHORT TERM MODEL TRENDS WOULD SUGGEST THIS WOULD WEAKEN AND BECOME SOMEWHAT LESS FOCUS AS IT TRANSLATES EASTWARD...THOUGH ENTIRE DEFORMATION PRECIP AREA WILL LIKELY BECOME A BIT BETTER ORGANIZED. WITH LESS PRECIPITATION...ESPECIALLY IN THE FORM OF SNOW ACROSS THE AREA DURING THE EARLY/MID EVENING HORUS...HAVE ADJUSTED SNOWFALL AMOUNTS DOWN SOMEWHAT FROM PREVIOUS FORECAST...GENERALLY 2-6 INCHES WITH THE HEAVIER AMOUNTS GENERALLY ALONG/NORTH OF INTERSTATE 88 IN NORTHERN/NORTHEAST IL. SOME HIGHER AMOUNTS STILL NOT OUT OF THE QUESTION GIVEN POTENTIAL FOR MESOSCALE BANDING...AND POTENTIAL FOR CONVECTION...BUT OVERALL CONFIDENCE REMAINS FAIRLY LOW EVEN AT THIS RELATIVELY CLOSE-IN TIME. SOUTH OF ROUGHLY A DVN-ORD LINE HOWEVER...THE HRRR WOULD INDICATE MORE CONVECTIVE SHOWERY TYPE PRECIP...WHICH HAS BEEN OCCURRING AS A MIX OF RAIN/SNOW/GRAUPEL PER REPORTS IN UPSTREAM AREAS. THIS APPEARS QUITE REASONABLE AS AREA OF STEEP MID-LEVEL LAPSE RATES...IN EXCESS OF 7 DEG/KM PER RUC/SPC MESOANALYSIS...WILL CONTINUE TO SPREAD ACROSS THE SOUTHERN PARTS OF THE CWFA OVERNIGHT. HAVE CONTINUED TO INDICATE SHOWERS/CHANCE THUNDER CHANGING TO SNOW DURING THE OVERNIGHT HOURS...WITH SNOWFALL AMOUNTS QUICKLY DECREASING THROUGH THE I-80 CORRIDOR SOUTHWARD. Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted February 24, 2012 Share Posted February 24, 2012 I dont know. Some one posted on accuwx forums. I believe its instantweathermaps, not sure. Also the total qpf thru 33 hours shows north gta in the .50 to .75 range. Well, I'm pretty much right on the Toronto/Markham border, so maybe I still have a chance at 4" Link to comment Share on other sites More sharing options...
cyclone77 Posted February 24, 2012 Share Posted February 24, 2012 Sorry to hear that. You are overdue for some snow....you have been going back and forth all day it seems. I dont get this storm much like I dont get this winter lol. It's been a lot of fun to track, that's for sure. Love these dynamic/slow moving systems. Never really expected a whole lot here. I still think we have a shot at my 3" call. Link to comment Share on other sites More sharing options...
michsnowfreak Posted February 24, 2012 Share Posted February 24, 2012 Webcams out of Toledo area show a blanket of snow already down. Link to comment Share on other sites More sharing options...
Justin Posted February 24, 2012 Share Posted February 24, 2012 Snow starting to mix back in here now. We have the potpourri of precip at the moment. Ground starting to get a little white now. Cars getting a nice coating. T/D of 34/32. Link to comment Share on other sites More sharing options...
QVectorman Posted February 24, 2012 Share Posted February 24, 2012 Would like to see the CC on the reflectivities over SE Mich. to see if those are bright bands or actually pockets of heavy snow over Lenawee, Jackson & Monroe co's. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 24, 2012 Share Posted February 24, 2012 I see Baro is about to post.. Breathing some common sense into equation. I don't really have much of anything to add. You guys have been looking at this with an eagle eye, I have just been an outside viewer. One thing for sure...this has been a slow storm to develop...slowest solution is prolly the most legit. Should really begin cranking overall 6 through15Z as the mid level wave amplifies and the poleward oriented jet becomes highly active. The secondary deformation band is going to be the big show here, and as others have mentioned, TSSN seems a legit threat especially across portions of MI since the moist conveyor belt will be feeding that front. Just looking at how things are unfolding, 12Z ECMWF may be a little light on precip...but it has otherwise been pretty stellar on precip placement and timing of snow changeovers. Link to comment Share on other sites More sharing options...
Snowstorms Posted February 24, 2012 Share Posted February 24, 2012 Well, I'm pretty much right on the Toronto/Markham border, so maybe I still have a chance at 4" Yeah lets see what happens tomorrow. Right now..i'm confused. The RR shows 4-6" lol Link to comment Share on other sites More sharing options...
Geos Posted February 24, 2012 Share Posted February 24, 2012 Snow is picking up here and it's cooled off a bit. 32.5°. 1.8" of snow. Link to comment Share on other sites More sharing options...
Ajdos Posted February 24, 2012 Share Posted February 24, 2012 Issued by The National Weather Service Detroit, MI Thu, Feb 23, 2012, 10:12 PM EST ... WINTER STORM WARNING REMAINS IN EFFECT UNTIL 7 PM EST FRIDAY... HAZARDOUS WEATHER...* SNOW WILL SPREAD FROM SOUTH TO NORTH OVER THE REGION BETWEEN 10 PM AND MIDNIGHT... AND THEN INCREASE INTENSITY DURING THE OVERNIGHT HOURS. A MIX OF RAIN AND SLEET WILL BE POSSIBLE AT THE ONSET ALONG AND SOUTH OF I 94. * THE PEAK OF THE EVENT WILL BE FROM 3 AM TO 9 AM... INCLUDING THE MORNING COMMUTE. * TOTAL SNOW ACCUMULATIONS WILL BE 5 TO 8 INCHES. AREAS SOUTH OF M 14 WILL BE CLOSER TO 3 OR 4 INCHES. ISOLATED LOCATIONS NORTH OF M 59 MAY EXCEED 8 INCHES... ESPECIALLY WITH ANY THUNDERSNOW THAT DEVELOPS DURING THE EARLY MORNING. * NORTH WINDS WILL GUST UP TO 30 MPH BY FRIDAY AFTERNOON RESULTING IN BLOWING AND DRIFTING SNOW. IMPACTS... * UNTREATED ROADS WILL BE HAZARDOUS THROUGH FRIDAY MORNING. * LIMITED VISIBILITY WILL MAKE TRAVEL CONDITIONS VERY SLOW DURING THE FRIDAY MORNING COMMUTE. * SOME BLOWING AND DRIFTING SNOW ON FRIDAY WILL CONTINUE TO MAKE FOR DIFFICULT DRIVING CONDITIONS THROUGH THE DAY... ESPECIALLY ON THE EAST-WEST ROADS. PRECAUTIONARY/PREPAREDNESS ACTIONS... * A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW EXPECTED. THIS WILL MAKE TRAVEL VERY HAZARDOUS. * PREPARE... PLAN... AND STAY INFORMED. Link to comment Share on other sites More sharing options...
QVectorman Posted February 24, 2012 Share Posted February 24, 2012 100 MU CAPE line creeping north Link to comment Share on other sites More sharing options...
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