Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 11/13/11


AREA FORECAST DISCUSSION
NWS TOPEKA KS
526 PM CST SAT NOV 12 2011 ...AVIATION UPDATE... .DISCUSSION... SEE PREV DISCUSSION. && .AVIATION... DRY AIR AHEAD OF THE UPPER LEVEL WAVE SHOULD PREVENT ANY WEATHER AND MAINTAIN VFR CONDITIONS. BIGGEST CONCERN WILL BE WITH LOW LEVEL WIND SHEAR AS THE LOW LEVEL JET INCREASES ABOVE THE NOCTURNAL INVERSION. THIS STRONG LOW LEVEL JET OF 50KTS WILL SHIFT TO THE WEST NORTHWEST AS THE UPPER WAVE PASSES OVERHEAD. WOLTERS && .PREV DISCUSSION... /246 PM CST SAT NOV 12 2011/ TONIGHT AND SUNDAY...20Z WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWS MOSTLY ZONAL FLOW OVER THE CENTRAL PART OF U.S. EMBEDDED WITHIN THE W-SW MID/UPPER LEVEL FLOW IS A WEAK SHORTWAVE TROUGH WHICH HAS SPAWNED INCREASING CLOUD COVER OVER THE CENTRAL MISSOURI AND NORTHERN ARKANSAS. ALTHOUGH THE WEAK SHORTWAVE TROUGH HAS MOVED OVER NORTHEAST KANSAS DRY AIR OVER THE AREA HAS PREVENTED MUCH IN THE WAY OF CLOUD FORMATION. THUS MOSTLY CLEAR SKIES ARE EXPECTED FOR THE REST OF THE DAY AND OVERNIGHT. EXPECT THE GUSTY WINDS TO TAPER OFF OVERNIGHT AS DIURNAL DECOUPLING BEGINS SHORTLY AFTER SUNSET. THE SURFACE PRESSURE GRADIENT WILL REMAIN FAIRLY TIGHT OVERNIGHT...SO EXPECT WESTERLY WINDS TO REMAIN IN THE 10 TO 15 MPH RANGE OVERNIGHT. BY LATE SATURDAY NIGHT/EARLY SUNDAY MORNING A FAIRLY SHARP AND QUICKLY MOVING 500 MB SHORTWAVE TROUGH WILL PUSH ACROSS THE NORTHERN PLAINS. THE ATMOSPHERIC COLUMN WILL REMAIN RATHER DRY AND THE BEST LIFT ASSOCIATED WITH THIS TROUGH WILL REMAIN WELL TO THE NORTH. AS A RESULT OF THOSE FACTORS...DO NOT EXPECT ANY RAIN IN NORTHEAST KANSAS. BY EARLY SUNDAY MORNING THE SURFACE LOW SITUATED ACROSS THE NORTHERN TIER WILL MOVE TO THE EAST...BRINGING WEST-NORTHWEST SURFACE FLOW TO NORTHEAST KANSAS ON SUNDAY. WEAK COLD AIR ADVECTION BEHIND THE COOL FRONT WILL KEEP TEMPS ON SUNDAY IN THE UPPER 50S TO LOWER 60S WITH INCREASING W-NW WINDS OF 15 TO 25 MPH. JL SUNDAY NIGHT THROUGH MONDAY NIGHT...A BROAD LONGER WAVE LENGTH UPPER LEVEL TROUGH WILL TRANSLATE EASTWARD ACROSS THE PLAINS. SHORTER WAVE LENGTH UPPER TROUGHS WILL DIG SOUTHEAST ACROSS THE HIGH PLAINS AND LIFT NORTHEAST INTO THE MIDWEST. THE DEEPER 850MB MOISTURE WILL REMAIN WELL SOUTH AND EAST OF THE CWA...THUS THE LOW-LEVELS OF THE ATMOSPHERE SHOULD REMAIN RELATIVELY DRY. THERE MAY ENOUGH ASCENT AHEAD OF AN H5 TROUGH LIFTING NORTHEAST ACROSS EASTERN KS SUNDAY NIGHT FOR AN INCREASE IN HIGH AND MID LEVEL CLOUDINESS AND POSSIBLY SOME SPRINKLES. HIGHS MONDAY WILL BE NEAR 60 NORTH OF INTERSTATE 70...WITH LOWER 60S SOUTH OF INTERSTATE 70. TUESDAY...AS THE LONGER WAVE LENGTH H5 TROUGH AXIS SHIFTS EAST OF THE PLAINS A SURFACE COLD FRONT WILL PUSH SOUTHWARD THROUGH THE CWA TUESDAY MORNING. HIGHS WILL ONLY REACH THE UPPER 40S ALONG THE NE BORDER WITH MID 50S POSSIBLE SOUTH OF I-35...THOUGH HIGHS MAY BE COOLER IF FROPA OCCURS EARLIER ON TUESDAY MORNING. A SFC RIDGE WILL BUILD SOUTHWARD ACROSS WESTERN KS THROUGH THE AFTERNOON HOUR. SKIES WILL BECOME MOSTLY SUNNY. GARGAN TUESDAY NIGHT THROUGH SATURDAY...ZONAL FLOW ALOFT WILL BE THE STORY FOR MOST OF THE WORK WEEK WITH DRY CONDITIONS AND TEMPERATURES NEAR NORMAL. DROPPED TEMPERATURES A COUPLE OF DEGREE BELOW GUIDANCE ON WEDNESDAY WITH 850 MB TEMPERATURES IN THE -5 TO -7 CELSIUS RANGE...LIGHT NORTHWEST WINDS ...CLEAR SKIES AND SURFACE HIGH PRESSURE OVER THE CENTRAL U.S. ON THURSDAY WINDS WILL SHIFT AROUND TO THE SOUTH AS SURFACE HIGH PRESSURE MOVES EAST INTO THE MID MISSISSIPPI RIVER VALLEY. WARM AIR ADVECTION WILL OCCUR AHEAD OF THE NEXT SYSTEM LATE THURSDAY THROUGH THE REMAINDER OF THE FORECAST AS LEE CYCLOGENESIS TAKES PLACE. HIGH TEMPERATURES WILL PUSH BACK UP INTO THE 60S ACROSS THE CWA ON FRIDAY AND SATURDAY AHEAD OF THE SURFACE LOW. BOTH THE 12Z GFS AND ECMWF ARE INDICATING JUST ENOUGH MOISTURE AHEAD OF THIS SYSTEM FOR A FEW SHOWERS TO DEVELOP ON SATURDAY WITH THE BEST CHANCES ACROSS EASTERN PORTIONS OF THE CWA. AT THIS TIME HAVE MENTIONED A SLIGHT CHANCE OF SHOWERS WITH BOTH THE GFS AND ECMWF ADVERTISING ENOUGH MOISTURE RETURN FOR A FEW SHOWERS TO DEVELOP ON SATURDAY. ANDERSON && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
854 PM EST SAT NOV 12 2011 ...Forecast Update... Wind gusts have weakened some with the sun setting, but we are still seeing some to around 20 knots. These winds are coming from a tight pressure gradient over the region, as we are between a 986 mb low now crossing into south central Canada and a 1027 mb high off the Carolina coast. Made some tweaks to the cloud cover forecast for the night, based on the expected clearing from the upper deck, moving into the central CWA from the west around 06z. Then model time height sections indicate some broad-scale lift, in association with a low-level jet now developing over central Missouri, forcing some lower level clouds to fill in before daybreak Sunday. With the winds and the separate cloud cover mentioned above, expect temperatures not to fall too much more than a few more degrees. Ongoing forecast for looks good, so just made some minor tweaks to deal with current obs for temps and dewpoints. Updated products are already out. && .Short Term (Tonight and Sunday)... ...Wind Advisory in effect Sunday... Expecting gusty winds to diminish over the next few hours although gradient winds will remain steady overnight, along with a few gusts. Have had a decent number of ob sites report gusts just over 30 mph this afternoon. Strong surface low will move from the northern plains across western Ontario tonight with surface high pressure anchored over the southeastern CONUS. Resulting tight pressure gradient over the Ohio valley will keep sustained southerly surface winds between 10 and 15 mph, increasing to between 15 and 25 mph by dawn on Sunday. A few gusts will also occur overnight as mechanical mixing from strong gradient will somewhat limit nocturnal inversion formation. The steady southerly winds, combined with mid clouds and increasing low level clouds will result in mild low temperatures in the lower 50s along and west of I-65. Further east, most locations can expect the upper 40s with a few possibly decoupled valleys dipping into the mid 40s. Pressure gradient will strengthen around dawn on Sunday through the afternoon with sustained south-southwesterly winds between 20 and 30 mph. Frequent gusts will range in the 30 to 40 mph, with the highest localized gusts around 45 mph. Time heights show vertical theta surfaces reaching into the bottom of a 60 knot low level jet and should be able yield a few gusts over 40 mph despite increasing clouds limiting turbulent mixing. Wind Advisory will be in effect from 9 am EST to 5 pm EST. Cold front trailing from above mentioned surface Low will move into the Wabash Valley by tomorrow evening with limited moisture pooling ahead of this boundary. Hi res models along with a few of the operational models show light QPF mainly along and north of the Ohio River tomorrow. Have scattered sprinkles early Sunday, transitioning to a 30 percent chance of a light rain shower Sunday afternoon. Areas south of the the line will remain dry. High temperatures will warm quite nicely despite the thickening cloud cover with the mercury reaching the mid and upper 60s in most spots. A few spots in the Bowling Green region could approach the 70 degree mark. .Long Term (Sunday night - Saturday)... Strong surface winds will continue sunday night into Monday, though these should remain below advisory criteria as the surface pressure gradient starts to weaken a bit. After more than two days of warm air and moisture advection from these winds though, the pump will be primed for showers and even a few thunderstorms to move through in advance of a slow moving cold front. The chance for showers will increase along and north of the Ohio River Sunday evening, then work its way east-southeastward over the CWA and persist through Tuesday evening. Thanks to the slow progress of this system, along with the bulk of the upper dynamics remaining over the Great Lakes, whatever thunderstorms that do occur should be relatively weak, with no widespread threat of severe weather expected. High temperatures on Monday will be 5-10 degrees above seasonal norms, hovering within a few degrees either side of 70. Despite the increase in precipitation over the area Tuesday, readings will still reach the lower 60s thanks to the continued southerly wind flow. By Wednesday, highs will top out in the 50s and remain there for the remainder of the week. Overnight lows will see the greatest variation through the week. After a balmy upper 50s start to the work week and Tuesday morning, more autumn-like lows in the 30s to lower 40s return by Wednesday, with some upper 20s in the picture for Thursday morning as clear skies and High pressure build in behind the cold front. && .Aviation (00Z TAF Issuance)... Tight pressure gradient remains over the region as we are in between low pressure moving into south central Canada and a strong high off the Carolina coast. This gradient should keep a steady southerly wind across the TAF sites overnight. Winds just above the surface are forecast to pick up overnight, creating low-level wind shear, as a broad low-level jet forms over central Missouri. The fringe of this jet will bring 50-60 kt winds at 2 kft over the TAF sites overnight. Have timed this strengthening in this set of TAFs based on a consensus of the NAM, GFS, and SREF. Models also consistently bring in some lower level clouds after 06z in time-height sections. HRRR hints at a narrow band of cigs around 3 kft as well. For now have kept in previous forecast for broken cigs around 4 kft and will monitor for changes once we see these clouds develop upstream. By mid morning Sunday, we may still deal with some shear, but expect winds to gust into the 30-35 kt range for the day, so will leave out for now. Light showers will move into the KSDF terminal towards the end of the day and continue overnight. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FROM 9 AM EST /8 AM CST/ TO 5 PM EST /4 PM CST/ SUNDAY FOR INZ076>079-083-084-089>092. KY...WIND ADVISORY FROM 9 AM EST /8 AM CST/ TO 5 PM EST /4 PM CST/ SUNDAY FOR KYZ023>043-045>049-053>057-061>067-070>078-081- 082. $$ Update...........RJS Short Term.......BJS Long Term........JBS Aviation.........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
629 PM EST SAT NOV 12 2011 ...Updated Aviation Discussion... .Short Term (Tonight and Sunday)... ...Wind Advisory in effect Sunday... Expecting gusty winds to diminish over the next few hours although gradient winds will remain steady overnight, along with a few gusts. Have had a decent number of ob sites report gusts just over 30 mph this afternoon. Strong surface low will move from the northern plains across western Ontario tonight with surface high pressure anchored over the southeastern CONUS. Resulting tight pressure gradient over the Ohio valley will keep sustained southerly surface winds between 10 and 15 mph, increasing to between 15 and 25 mph by dawn on Sunday. A few gusts will also occur overnight as mechanical mixing from strong gradient will somewhat limit nocturnal inversion formation. The steady southerly winds, combined with mid clouds and increasing low level clouds will result in mild low temperatures in the lower 50s along and west of I-65. Further east, most locations can expect the upper 40s with a few possibly decoupled valleys dipping into the mid 40s. Pressure gradient will strengthen around dawn on Sunday through the afternoon with sustained south-southwesterly winds between 20 and 30 mph. Frequent gusts will range in the 30 to 40 mph, with the highest localized gusts around 45 mph. Time heights show vertical theta surfaces reaching into the bottom of a 60 knot low level jet and should be able yield a few gusts over 40 mph despite increasing clouds limiting turbulent mixing. Wind Advisory will be in effect from 9 am EST to 5 pm EST. Cold front trailing from above mentioned surface Low will move into the Wabash Valley by tomorrow evening with limited moisture pooling ahead of this boundary. Hi res models along with a few of the operational models show light QPF mainly along and north of the Ohio River tomorrow. Have scattered sprinkles early Sunday, transitioning to a 30 percent chance of a light rain shower Sunday afternoon. Areas south of the the line will remain dry. High temperatures will warm quite nicely despite the thickening cloud cover with the mercury reaching the mid and upper 60s in most spots. A few spots in the Bowling Green region could approach the 70 degree mark. .Long Term (Sunday night - Saturday)... Strong surface winds will continue sunday night into Monday, though these should remain below advisory criteria as the surface pressure gradient starts to weaken a bit. After more than two days of warm air and moisture advection from these winds though, the pump will be primed for showers and even a few thunderstorms to move through in advance of a slow moving cold front. The chance for showers will increase along and north of the Ohio River Sunday evening, then work its way east-southeastward over the CWA and persist through Tuesday evening. Thanks to the slow progress of this system, along with the bulk of the upper dynamics remaining over the Great Lakes, whatever thunderstorms that do occur should be relatively weak, with no widespread threat of severe weather expected. High temperatures on Monday will be 5-10 degrees above seasonal norms, hovering within a few degrees either side of 70. Despite the increase in precipitation over the area Tuesday, readings will still reach the lower 60s thanks to the continued southerly wind flow. By Wednesday, highs will top out in the 50s and remain there for the remainder of the week. Overnight lows will see the greatest variation through the week. After a balmy upper 50s start to the work week and Tuesday morning, more autumn-like lows in the 30s to lower 40s return by Wednesday, with some upper 20s in the picture for Thursday morning as clear skies and High pressure build in behind the cold front. && .Aviation (00Z TAF Issuance)... Tight pressure gradient remains over the region as we are in between low pressure moving into south central Canada and a strong high off the Carolina coast. This gradient should keep a steady southerly wind across the TAF sites overnight. Winds just above the surface are forecast to pick up overnight, creating low-level wind shear, as a broad low-level jet forms over central Missouri. The fringe of this jet will bring 50-60 kt winds at 2 kft over the TAF sites overnight. Have timed this strengthening in this set of TAFs based on a consensus of the NAM, GFS, and SREF. Models also consistently bring in some lower level clouds after 06z in time-height sections. HRRR hints at a narrow band of cigs around 3 kft as well. For now have kept in previous forecast for broken cigs around 4 kft and will monitor for changes once we see these clouds develop upstream. By mid morning Sunday, we may still deal with some shear, but expect winds to gust into the 30-35 kt range for the day, so will leave out for now. Light showers will move into the KSDF terminal towards the end of the day and continue overnight. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FROM 9 AM EST /8 AM CST/ TO 5 PM EST /4 PM CST/ SUNDAY FOR INZ076>079-083-084-089>092. KY...WIND ADVISORY FROM 9 AM EST /8 AM CST/ TO 5 PM EST /4 PM CST/ SUNDAY FOR KYZ023>043-045>049-053>057-061>067-070>078-081- 082. $$ Short Term.......BJS Long Term........JBS Aviation.........RJS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
916 PM EST SAT NOV 12 2011 .SYNOPSIS... A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE REGION TONIGHT AND THEN MOVE EAST OF THE AREA SUNDAY AND MONDAY.&& .NEAR TERM /THROUGH SUNDAY/... UPDATE: DECREASED POPS ACROSS THE N AND NE AND MADE ANOTHER MINOR ADJUSTMENT TO THE HRLY TEMPS... SHORTWAVE TROUGH JUST WEST OF THE REGION THIS AFTERNOON WILL CROSS THE STATE BY EARLY THIS EVENING. SAT IMG INDICATES OVERCAST SKIES ACROSS MOST OF NORTHERN AND CENTRAL SECTIONS WITH A MIX OF SUN AND CLOUDS ACROSS DOWNEAST THIS AFTERNOON. RH PROGS INDICATE CLOUDS TO REMAIN ACROSS MOST OF NORTHERN AND CENTRAL SECTIONS INTO EARLY THIS EVENING THEN GRADUALLY CLEARING THE REMAINDER OF THE NIGHT WITH THE TROUGH PASSAGE. CLOUDS WILL DISSIPATE ACROSS DOWNEAST BY EARLY THIS EVENING. RADAR INDICATING SCATTERED SNOW SHOWERS/FLURRIES HAVE DEVELOPED ACROSS NORTHERN AND CENTRAL SECTIONS. HRRR AND RUC MODELS INDICATE THIS ACTIVITY WILL CONTINUE UNTIL UPPER TROUGH MOVES EAST OF THE REGION EARLY THIS EVENING. UPPER RIDGE CRESTS THE STATE EARLY SUNDAY MORNING AND THEN MOVES EAST OF THE REGION BY NOONTIME. SOUTHWEST FLOW ON THE BACKSIDE OF THE RIDGE WILL ALLOW WARM AIR ADVECTION TO OCCUR ACROSS THE STATE WITH TEMPERATURES MODERATING INTO THE MID TO UPPER 40S ACROSS THE NORTH AND THE 50S ACROSS DOWNEAST.&& .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... UNSETTLED WEATHER IS EXPECTED THROUGH THE SHORT TERM PERIOD AS A SERIES OF WAVES MOVES THROUGH SOUTHWEST FLOW ALOFT. THE FIRST WILL COME SUNDAY NIGHT AND WILL REMAIN TO OUR NORTH AND WEST. IT WILL BE ENOUGH TO FIRE UP SOME SHOWERS ACROSS NORTHERN MAINE THROUGH EARLY MONDAY AFTERNOON. THE NEXT GOOD CHANCE OF PRECIPITATION ARRIVES MONDAY NIGHT WITH YET ANOTHER WEAK IMPULSE TO TRAVERSE ACROSS THE REGION. BRIEF RIDGING WILL BUILD OVER NORTHERN NEW ENGLAND IN ITS WAKE...SO EXPECT THERE WILL BE A BRIEF DRY SPELL TUESDAY BEFORE A STRONGER SYSTEM APPROACHES FROM THE WEST. RAIN FROM THIS FINAL WAVE WILL SPREAD INTO MAINLY SOUTHERN SECTIONS OF THE FORECAST AREA LATE TUESDAY AFTERNOON. THE UPSIDE OF ALL THESE SHORTWAVES WILL BE MILD TEMPERATURES AS THEY LOOK TO STAY FAR ENOUGH NORTH THAT WE WILL STAY OUT OF THE COLD AIR. DAYTIME HIGHS WILL RANGE FROM AROUND 50 NORTH TO THE UPPER 50S DOWNEAST...AND OVERNIGHT LOWS IN THE 40S DUE TO CLOUD COVER. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... RAIN SHOULD BE SPREADING NORTHWARD ON TUESDAY NIGHT IN RESPONSE TO A LOW PRESSURE SYSTEM MOVING ALONG THE COAST OF MAINE. THERE ARE STILL SOME DIFFERENCES IN THE GFS AND ECMWF IN THIS TIME FRAME. THE GFS WANTS TO BRING THE LOW THROUGH ON TUESDAY NIGHT INTO WEDNESDAY...ON THE OTHER HAND IT SEEMS AS IF THE ECMWF IS ABOUT 18 TO 24 HOURS SLOWER. WILL LEAN WITH GFS WITH THIS PACKAGE. RAIN SHOULD END LATE WEDNESDAY EVENING. HIGH PRESSURE THEN MOVES IN FOR THURSDAY THROUGH FRIDAY EVENING BEFORE A WEAK SYSTEM PASSES OFF TO THE NORTH BRINGING A SLIGHT CHANCE OF PRECIP. TEMPERATURES AFTER THE STORM WEDNESDAY WILL RETURN TO NORMAL NOVEMBER AVERAGES THROUGH SATURDAY. USED A BLEND OF GMOS AND GFS FOR THE PERIOD AND ADJUSTED AS NEEDED. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... NEAR TERM: VFR CONDITIONS TONIGHT AND SUNDAY. FLURRIES POSSIBLE ACROSS NORTHERN TERMINALS INTO EARLY THIS EVENING BUT SHOULD NOT RESTRICT VSBY. SHORT TERM: VFR WITH PERIODS OF MVFR IN RAIN SHOWERS EXPECTED THROUGH THE PERIOD. && .MARINE... NEAR TERM: SCA WINDS AND SEAS CONTINUE ACROSS THE WATERS THIS EVENING AND THEN EXPECT WINDS TO DROP BELOW SCA CRITERIA AFTER MIDNIGHT. HOWEVER, SEAS ABOVE 5 FEET DUE TO SWELL WILL CONTINUE THROUGH THE NIGHT SO WILL KEEP SCA GOING FOR THE ENTIRE NIGHT. SHORT TERM: SOUTHWEST WINDS OF 15 TO 25 KT ARE EXPECTED SUNDAY NIGHT AND MONDAY AS LOW PRESSURE SKIRTS BY TO THE NORTH OF THE WATERS. A SMALL CRAFT ADVISORY WILL PROBABLY BE NEEDED...FOR WAVES AS WELL AS WINDS. CONDITIONS WILL SUBSIDE MONDAY NIGHT BUT WILL INCREASE TO CLOSE TO SCA CRITERIA AGAIN TUESDAY AHEAD OF ANOTHER LOW PRESSURE SYSTEM. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ050>052. && $$ NEAR TERM...KHW/FOSTER SHORT TERM...HASTINGS LONG TERM...HILL AVIATION...KHW/FOSTER MARINE...KHW/FOSTER/HASTINGS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
544 PM CST Sat Nov 12 2011 ...UPDATED AVIATION DISCUSSION... .DISCUSSION... Short Range (Tonight through Monday)... High cloud cover associated with a shortwave in Kansas with quickly shift east late this afternoon and this evening. The next shortwave trough in eastern Idaho will pass through Nebraska and Iowa and have no affect on Missouri...given the meager moisture in place. The shortwave trough will drive a surface trough into Missouri late tonight and early Sunday with little if any cooling on Sunday. For Monday and Monday night...models are similar with the upper trough off the Baja coast. The trough will pass well to the south of the forecast area with only a weak upper trough passage on Monday. Given the lack of moisture...have significantly lowered the threat of any showers for the southeast grids on Monday. Given the downslope winds the next couple of days...prefer the warmest of the guidance. DB Medium Range (Tuesday through Saturday)... Mid-range models, as of the 12Z/12 model run, have all converged towards a similar solution for next weeks weather, which could be characterized best as a fast zonal flow. As Tuesday arrives, a circulation, currently swinging from the eastern Pacific towards Baja Mexico, will have sheared apart and been absorbed by a broad trough that will be shifting across the CONUS. Westerlies moving under the trough will only be displaced south a little, thus much of the cold air to the north of the westerlies will remain trapped to our north through the work week. As a result, expect afternoon highs and overnight lows to remain within in a category or two of normal through the work week. However, by the end of next work week, all the mid-range models advertise a significant trough shifting across the West Coast, with a southwest flow quickly developing across the Central Plains States. This should result in temperatures drifting back above normal for Friday and Saturday, but also might result in showers. Moisture return in the southwest flow looks a little iffy, as it will be taking the scenic route from the Gulf through central Texas before hanging a right and heading north. Models all paint significant showers across the region by Saturday, but thoughts are that focus for much of the activity will be farther north, associated with lifting warm front across Iowa. However, will keep the slight chance POPs that the consensus model output is advertising for now. Cutter && .AVIATION... For the 00Z TAFs...Main concern will be low level winds as a 40-50 kt southwesterly low level jet develops across much of Missouri overnight. Both NAM and RUC indicate winds at 2000 ft increasing to near or higher than 50 kt for a short period around sunrise as a low level trough swings through, so added LLWS into the TAFs for this period. Some of these winds may mix down to the surface overnight, translating to gusts in the 20-25 kt range. Other concern will be the potential for MVFR or even IFR cigs to develop overnight as low level winds advect increasing moisture below 2000 ft. At this time, expect bulk of moisture and any low cigs to stay east of the STJ-MCI-MKC corridor, affecting mainly central Missouri and points east. Hawblitzel && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
928 PM MST SAT NOV 12 2011 .UPDATE...THE MOUNTAIN WINDS ARE BLOWING STRONG IN POCKETS MAINLY NEAR THE CONTINENTAL DIVIDE. THE SNOWFALL HAS NOT BEEN OVERLY IMPRESSIVE SO FAR. AT 9 PM RADAR INDICATES THE COLD FRONT WAS ORIENTED W-E JUST SOUTH OF MEEKER. THE 00Z NAM SHOWS LITTLE ADDITIONAL FRONTOGENETICAL FORCING WITH THIS FEATURE TONIGHT AS MOST OF ITS ENERGY SHEARS EAST OF THE DIVIDE. THEREFORE THE EAGLE PORTION OF THE I-70 CORRIDOR WILL STAY IN THE WARM SECTOR OF THE STORM AND WILL PRODUCE RAIN TONIGHT INSTEAD OF SNOW. NORTH OF THE FRONT...GUSTY WINDS WILL REMAIN STRONG BUT SNOWFALL WILL DIMINISH IN A LULL BEFORE THE NEXT UPPER WAVE ARRIVES EARLY SUNDAY MORNING. SOUTH OF THE COLD FRONT...SNOW ACCUMULATIONS EXPECTED TO BE LIGHT TONIGHT MAINLY OROGRAPHICALLY DRIVEN IN THE STRONG WEST FLOW. THE SW SAN JUAN MTNS...ALWAYS ON THE CUSP OF A HIGHLIGHT SNOW AMOUNT WILL MOST LIKELY ONLY SEE A FEW INCHES OF SNOWFALL ON SUNDAY. THEREFORE HAVE PULLED DOWN ADVISORIES FOR THERE AND THE EAGLE AREA. ONE WORRISOME DETAIL FOR THE NORTHERN VALLEYS...THE OVERRUNNING EVENT TOWARDS SUNDAY MORNING NOW NEVER SATURATES FULLY WITHIN THE DENDRITIC CRYSTAL GROWTH REGION. WE WILL LOOK AT THIS AND OTHER DETAILS FOR THE MORNING FORECAST PACKAGE. && .PREVIOUS DISCUSSION... /ISSUED 851 PM MST SAT NOV 12 2011/ .SHORT TERM /TONIGHT THROUGH MONDAY/... AT 2 PM THE SURFACE FRONT WAS THROUGH SLC AND APPROACHING PROVO AND VERNAL...WITH SNOW FALLING AT HILL AFB AND EVANSTON WY...SO IT IS RIGHT ON TRACK ACCORDING TO MODEL TIMING. ALSO AS PROJECTED THE ACTIVE AREA OF THE FRONT IS DIMINISHING IN SIZE AND THE FRONTAL ZONE IS GROWING THINNER IN SATELLITE IMAGERY AND RUC ANALYSIS. THE PERIOD OF MAXIMUM ACTIVE WEATHER IN NE UT AND NW CO WILL BE RELATIVELY BRIEF TONIGHT. PRIME TIME FOR BEST SNOWFALL AND STRONGEST WINDS SHOULD BE BETWEEN 9 PM AND MIDNIGHT. HAVE INCREASED THE CHC OF PRECIP OVER THE NORTHERN 2/3RDS OF THE AREA...VALLEYS AND MOUNTAINS...FOR THIS EVENING AND OVERNIGHT...HAVING HIGHER CERTAINTY WITH THIS INITIAL SPURT OF RAIN AND SNOW. THE SNOWFALL IN THE MOUNTAINS SHOULD BE ENOUGH FOR SEVERAL INCHES TO ACCUMULATE...ALONG WITH STRONG WESTERLY FLOW AT AND JUST BELOW MOUNTAINTOP LEVEL. THIS SHOULD BE ENOUGH FOR THE BLIZZARD CONDITIONS TO MATERIALIZE. STILL EXPECT RABBIT EARS AND VAIL PASSES TO SEE G50-60MPH THIS EVENING...WITH DRIFTING AND WHITEOUT CONDITIONS MAKING TRAVEL DANGEROUS IF NOT IMPOSSIBLE. AFTER THIS FRONT PASSES THERE WILL BE A LULL IN THE WINTER WEATHER BETWEEN 06Z AND 12Z TONIGHT. THIS WILL BE FOLLOWED BY A SECOND SURGE SUNDAY. THIS WEAKER FRONT WILL BRING COOLER AIR THAT WILL RUN INTO SLIGHTLY WARMER AIR IN PLACE OVER THE AREA. SOME OVERRUNNING IS POSSIBLE RESULTING IN WIDESPREAD SNOWFALL OVER NW AND CENTRAL CO... INCLUDING THE LOWER ELEVATIONS. COLDER CONDITIONS AND RAPID CLEARING WILL FOLLOW THE SECOND SYSTEM SUNDAY NIGHT AND MONDAY. THANKS TO BOU PUB AND ABQ FOR COORDINATION. .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... SHORT-WAVE TRAIN FROM THE ALEUTIANS INTO THE NORTHERN PLAINS BEHIND THIS STORM SYSTEM AND RE-ENFORCE THE NORTHWEST FLOW OVER THE NORTHERN ROCKIES LATE MONDAY NIGHT INTO TUESDAY. 295K THETA SURFACE NOT SHOWING A LARGE AMOUNT OF MOISTURE MOVING IN FROM THE PACIFIC...BUT IT IS TAKING A FAVORABLE ROUTE AND NOT BEING SQUEEZED OUT BY ANY BIG RANGES BEFORE HITTING THE NORTHERN COLORADO MOUNTAINS. THE LARGE SCALE ASCENT INCREASES AFTER MIDNIGHT ON MONDAY WHEN JET SUPPORT ARRIVES ALONG WITH THE STRONGEST OF THE EMBEDDED WAVES. OROGRAPHICS SHOULD CONTINUE TO FAVOR THE WESTERN ASPECTS FROM STEAMBOAT DOWN TO CRESTED BUTTE...AND HAVE NUDGED POPS UP SLIGHTLY WITH ONLY A FEW INCHES OF ACCUMULATION STILL INDICATED. THE UPPER FLOW PATTERN WILL BEGIN TO DE-AMPLIFY DURING THE MID WEEK TIME FRAME BUT A BUILDING RIDGE INTO THE NORTHEAST PACIFIC/GULF OF ALASKA REGION...WILL ALLOW FOR ANOTHER TROF TO BEGIN TO CARVE OUT ACROSS THE NORTHWEST STATES BY LATE IN THE WEEK. THE TREND THE WESTERN TROF FORMATION HAS BEEN SLOWED DOWN FROM PREVIOUS RUNS AND THIS SHOULD KEEP MAINLY DRY CONDITIONS IN PLACE THROUGH LATE WEEK. WITH THE STRONGER WESTERLY...THEN SOUTHWESTERLY FLOW IN PLACE A REBOUND IN TEMPERATURES SHOULD OCCUR AND TEMPERATURES SHOULD RISE TO AT LEAST SEASONAL LEVELS BY MID WEEK AND POSSIBLY ABOVE IN AN INCREASING WARM AIR ADVECTION PATTERN. THERE ARE SOME TIMING DIFFERENCES BY THE FIRST HALF OF NEXT WEEKEND WHEN THE FIRST LEADING ENERGY EJECTS FROM THE TROF INTO THE EASTERN GREAT BASIN AND THEREFORE PRECIPITATION CHANCES WILL REMAIN ON THE LOW SIDE. && .AVIATION /FOR 06Z TAF ISSUANCE/... WITH THE COLD FRONT BECOMING STATIONARY JUST NORTH OF THE I-70 CORRIDOR... LOCAL IFR/LIFR CONDITIONS WILL CONTINUE OVER THE MOST MTNS OVERNIGHT. A SECOND UPPER WAVE WILL BRING A CHANCE OF SHRASN TO THE VALLEYS TOWARDS SUNDAY MORNING AND MTNS WILL BE MOSTLY OBSCURED. STRONG WEST WINDS OF 40-60KTS AT 10,000FT MSL WILL PRODUCING STRONG TURBULENCE. THE HIGHER TERMINAL SITES WILL MOST LIKELY SEE IFR/LIFR CONDITIONS THROUGH THE NIGHT IN LIGHT TO MODERATE SNOW WITH THE MOUNTAINS AND HIGHER PASSES OBSCURED BY LOW CLOUDS AND PRECIPITATION. LOWER ELEVATIONS TAF SITES SUCH AS KGJT...KMTJ...KVEL WILL SLOWLY DEGRADE TOWARD SUNRISE ON SUNDAY WHEN A SECONDARY SYSTEM PUSHES THROUGH WITH ADDITIONAL MOISTURE. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL 6 PM MST SUNDAY FOR ZONES 002-003- 005-009-018. WINTER STORM WARNING UNTIL MIDNIGHT MST SUNDAY NIGHT FOR ZONES 010-012. BLIZZARD WARNING UNTIL MIDNIGHT MST SUNDAY NIGHT FOR ZONES 004-013. UT...NONE. && $$ UPDATE.......JOE SHORT TERM...CJC LONG TERM....15 AVIATION.....TGJT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1221 AM EST SUN NOV 13 2011 .SYNOPSIS... A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE REGION TONIGHT AND THEN MOVE EAST OF THE AREA SUNDAY AND MONDAY. && .NEAR TERM /THROUGH SUNDAY/... HAVE ADJUSTED TEMPERATURE GRIDS. SHORTWAVE TROUGH JUST WEST OF THEREGION THIS AFTERNOON WILL CROSS THE STATE BY EARLY THIS EVENING. SAT IMG INDICATES OVERCAST SKIES ACROSS MOST OF NORTHERN AND CENTRAL SECTIONS WITH A MIX OF SUN AND CLOUDS ACROSS DOWNEAST THIS AFTERNOON. RH PROGS INDICATE CLOUDS TO REMAIN ACROSS MOST OF NORTHERN AND CENTRAL SECTIONS INTO EARLY THIS EVENING THEN GRADUALLY CLEARING THE REMAINDER OF THE NIGHT WITH THE TROUGH PASSAGE. CLOUDS WILL DISSIPATE ACROSS DOWNEAST BY EARLY THIS EVENING. RADAR INDICATING SCATTERED SNOW SHOWERS/FLURRIES HAVE DEVELOPED ACROSS NORTHERN AND CENTRAL SECTIONS. HRRR AND RUC MODELS INDICATE THIS ACTIVITY WILL CONTINUE UNTIL UPPER TROUGH MOVES EAST OF THE REGION EARLY THIS EVENING. UPPER RIDGE CRESTS THE STATE EARLY SUNDAY MORNING AND THEN MOVES EAST OF THE REGION BY NOONTIME. SOUTHWEST FLOW ON THE BACKSIDE OF THE RIDGE WILL ALLOW WARM AIR ADVECTION TO OCCUR ACROSS THE STATE WITH TEMPERATURES MODERATING INTO THE MID TO UPPER 40S ACROSS THE NORTH AND THE 50S ACROSS DOWNEAST. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... UNSETTLED WEATHER IS EXPECTED THROUGH THE SHORT TERM PERIOD AS A SERIES OF WAVES MOVES THROUGH SOUTHWEST FLOW ALOFT. THE FIRST WILL COME SUNDAY NIGHT AND WILL REMAIN TO OUR NORTH AND WEST. IT WILL BE ENOUGH TO FIRE UP SOME SHOWERS ACROSS NORTHERN MAINE THROUGH EARLY MONDAY AFTERNOON. THE NEXT GOOD CHANCE OF PRECIPITATION ARRIVES MONDAY NIGHT WITH YET ANOTHER WEAK IMPULSE TO TRAVERSE ACROSS THE REGION. BRIEF RIDGING WILL BUILD OVER NORTHERN NEW ENGLAND IN ITS WAKE...SO EXPECT THERE WILL BE A BRIEF DRY SPELL TUESDAY BEFORE A STRONGER SYSTEM APPROACHES FROM THE WEST. RAIN FROM THIS FINAL WAVE WILL SPREAD INTO MAINLY SOUTHERN SECTIONS OF THE FORECAST AREA LATE TUESDAY AFTERNOON. THE UPSIDE OF ALL THESE SHORTWAVES WILL BE MILD TEMPERATURES AS THEY LOOK TO STAY FAR ENOUGH NORTH THAT WE WILL STAY OUT OF THE COLD AIR. DAYTIME HIGHS WILL RANGE FROM AROUND 50 NORTH TO THE UPPER 50S DOWNEAST...AND OVERNIGHT LOWS IN THE 40S DUE TO CLOUD COVER. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... RAIN SHOULD BE SPREADING NORTHWARD ON TUESDAY NIGHT IN RESPONSE TO A LOW PRESSURE SYSTEM MOVING ALONG THE COAST OF MAINE. THERE ARE STILL SOME DIFFERENCES IN THE GFS AND ECMWF IN THIS TIME FRAME. THE GFS WANTS TO BRING THE LOW THROUGH ON TUESDAY NIGHT INTO WEDNESDAY...ON THE OTHER HAND IT SEEMS AS IF THE ECMWF IS ABOUT 18 TO 24 HOURS SLOWER. WILL LEAN WITH GFS WITH THIS PACKAGE. RAIN SHOULD END LATE WEDNESDAY EVENING. HIGH PRESSURE THEN MOVES IN FOR THURSDAY THROUGH FRIDAY EVENING BEFORE A WEAK SYSTEM PASSES OFF TO THE NORTH BRINGING A SLIGHT CHANCE OF PRECIP. TEMPERATURES AFTER THE STORM WEDNESDAY WILL RETURN TO NORMAL NOVEMBER AVERAGES THROUGH SATURDAY. USED A BLEND OF GMOS AND GFS FOR THE PERIOD AND ADJUSTED AS NEEDED. && .AVIATION /05Z SUNDAY THROUGH THURSDAY/... NEAR TERM: VFR CONDITIONS TONIGHT AND SUNDAY. FLURRIES POSSIBLE ACROSS NORTHERN TERMINALS INTO EARLY THIS EVENING BUT SHOULD NOT RESTRICT VSBY. SHORT TERM: VFR WITH PERIODS OF MVFR IN RAIN SHOWERS EXPECTED THROUGH THE PERIOD. && .MARINE... NEAR TERM: SCA WINDS AND SEAS CONTINUE ACROSS THE WATERS THIS EVENING AND THEN EXPECT WINDS TO DROP BELOW SCA CRITERIA AFTER MIDNIGHT. HOWEVER, SEAS ABOVE 5 FEET DUE TO SWELL WILL CONTINUE THROUGH THE NIGHT SO WILL KEEP SCA GOING FOR THE ENTIRE NIGHT. SHORT TERM: SOUTHWEST WINDS OF 15 TO 25 KT ARE EXPECTED SUNDAY NIGHT AND MONDAY AS LOW PRESSURE SKIRTS BY TO THE NORTH OF THE WATERS. A SMALL CRAFT ADVISORY WILL PROBABLY BE NEEDED...FOR WAVES AS WELL AS WINDS. CONDITIONS WILL SUBSIDE MONDAY NIGHT BUT WILL INCREASE TO CLOSE TO SCA CRITERIA AGAIN TUESDAY AHEAD OF ANOTHER LOW PRESSURE SYSTEM. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ050>052. && $$ NEAR TERM...MIGNONE
AREA FORECAST DISCUSSION
NWS EUREKA CA
445 AM PST SUN NOV 13 2011 .SYNOPSIS... ANY LINGERING CLOUDS WILL GIVE WAY TO SUNSHINE TODAY. GENERALLY DRY WEATHER WILL CONTINUE THROUGH EARLY NEXT WEEK WITH JUST SOME OCCASIONAL SLIGHT CHANCES FOR LIGHT RAINFALL NEAR THE OREGON BORDER. THE NEXT CHANCE FOR A SUBSTANTIAL RAINFALL WILL ARRIVE WEDNESDAY NIGHT INTO THURSDAY WITH COOLER AND DAMP WEATHER CONTINUING INTO THE WEEKEND. && .DISCUSSION... SHOWER ACTIVITY ASSOCIATED WITH A WEAK TROUGH PUSHING INLAND ACROSS OREGON HAS PUSHED THROUGH A BIT QUICKER THAN PROGGED THUS PULLED POPS FROM THE REST OF TODAY. RUC ANALYSIS SHOWS WEAK VORT MAX CONTINUING TO PUSH TO OUR SOUTH WITH NVA ACROSS NRN CA. DRYING IS ALREADY OCCURRING AT THE MID LEVELS BUT THERE IS STILL SOME LOW LEVEL MOISTURE LAGGING BEHIND AS EVIDENCED BY SOME LOWER CEILINGS AT NORTH COASTAL SITES. ALL INDICATIONS ARE THAT THESE WILL SCATTER OUT NO LATER THAN THIS AFTERNOON. MODELS CONTINUE THIS PATTERN OF WNW FLOW WITH WEAK DISTURBANCES PASSING BY IN ONSHORE FLOW. THE GENERAL TREND WILL BE FOR HEIGHTS TO RISE AND DRIER AIR TO MOVE IN THROUGH WEDNESDAY AHEAD OF THE NEXT SIGNIFICANT SYSTEM WED NT/THU...ALTHOUGH EVEN THIS SYSTEM DOES NOT LOOK AS MAJOR AS EARLIER ADVERTISED. KEPT SLIGHT CHANCES FOR A COUPLE PERIODS MON NT/TUE BUT AM NOT CONVINCED WE SEE ANY MORE THAN THE SHOWER OR TWO THAT WE SAW WITH THIS CURRENT PASSING TROUGH. CLOUD COVER WILL BE MORE PROBLEMATIC. THIS TIME OF YEAR EXPECT LESS IN THE WAY OF FOG OR REALLY LOW CEILINGS WITH THE TENDENCY FOR MORE MIXING AND SUNSHINE ESPECIALLY NEAR THE COAST EACH AFTERNOON. MODELS DIFFER ON DETAILS OF COLD UPPER TROUGH PROGRESSION FOR LATE WEEK BUT THE BOTTOM LINE WILL BE A COOL SHOWERY PATTERN WITH MUCH LOWER SNOW LEVELS. HOWEVER THIS DOES NOT LOOK LIKE A SIGNIFICANT PRECIPITATION PRODUCER FOR AT THIS TIME. && .AVIATION...PRIMARILY VFR WITH MID TO HIGH CIGS TODAY AND TONIGHT. SOME PATCHY MVFR CIGS AT THE COAST NEAR KACV FROM ADVECTING MARINE STRATOCUMULUS THIS MORNING SHOULD SCATTER OUT BY MID MORNING. MKN && .MARINE...N WINDS WILL CONTINUE TODAY AND THEN GRADUALLY SUBSIDE OVERNIGHT. AS WINDS SUBSIDE BELOW SCA VALUES THE NW SWELL IS INCREASING OVERNIGHT INTO MONDAY SO SMALL CRAFT ADVISORIES CONTINUE OFF SHORE AND ARE IN PLACE FOR TONIGHT THRU TUE INSIDE 10 NM. MKN && .EKA WATCHES/WARNINGS/ADVISORIES... CA...NONE. NORTHWEST CALIFORNIA COASTAL WATERS... SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 3 PM PST TUESDAY PZZ450-455. SMALL CRAFT ADVISORY UNTIL 3 PM PST TUESDAY PZZ470-475. && $$ VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA FOLLOW US ON FACEBOOK AT: HTTP://WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.EUREKA.GOV
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
824 AM EST SUN NOV 13 2011 .SYNOPSIS... A SLOWLY EASTWARD MOVING COLD FRONT WILL PROVIDE THE UPPER OHIO VALLEY WITH WINDY MILD CONDITIONS TODAY, THEN SHOWERS LATE TONIGHT INTO TUESDAY NIGHT, FOLLOWED BY CHILLY CONDITIONS WEDNESDAY INTO FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RECENT NAM MODEL OUTPUT AND 12Z UPPER AIR DATA SUPPORT THE IDEA OF DRY, MILD CONDITIONS ACCOMPANIED BY GUSTY WINDS TODAY. FORECASTED A DECENT AMOUNT OF SUNSHINE AGAIN TODAY, WHICH WILL PROMOTE THE VERTICAL MIXING TO TAP THE FAST WINDS ALOFT TO CAUSE THE GUSTY WINDS. NAM MODEL PROFILES SUGGEST GUSTS CAN REACH 35 TO 40 MPH. AFTERNOON HIGHS CAN BE 10 TO 15 DEGREES WARMER THAN NORMAL, AS SUGGESTED BY BLEND OF RECENT GFS AND NAM MOS AND HRRR MODEL OUTPUT. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... PER BLEND OF RECENT SREF MODEL OUTPUT, CONTINUE TO EXPECT THE FIRST SHOWERS ASSOCIATED WITH THE INCOMING COLD FRONTAL SYSTEM TO BEGIN SPREADING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY TONIGHT. SHOWERS WILL BECOME MORE NUMEROUS LATE TONIGHT. CONTINUED SOUTHWEST WINDS, IN ADVANCE OF THE FRONT, WILL SUPPORT WARM OVERNIGHT LOWS...APPROXIMATELY 15 DEGREES ABOVE AVERAGE...AGAIN FORECAST USING A GUIDANCE BLEND. LIKELY PRECIP PROBABILITIES WERE FORECAST FOR THE REMAINDER OF THE SHORT TERM PERIOD AS A SERIES OF SHORTWAVES ARE PROJECTED TO MOVE THROUGH THE BAROCLINIC ZONE OVER THE UPPER OHIO REGION. USING A CONSERVATIVE APPROACH TO RAINFALL RATES DUE TO PROGRESSIVE NATURE OF THOSE DISTURBANCES...QUANTITATIVE PRECIPITATION FORECASTS WERE LIMITED TO JUST OVER AN INCH FOR THE PERIOD AT THIS JUNCTURE. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... PER BLEND OF RECENT NAEFS AND ECMWF MODEL OUTPUT, EXPECT SHOWER BANDS ASSOCIATED WITH COLD FRONTAL SYSTEM TO BE EXITING PAST THE MOUNTAINS ON WEDNESDAY. COLD POST-SYSTEM WESTERLY FLOW WILL PROVIDE COLDER THAN NORMAL TEMPERATURES WEDNESDAY AND THURSDAY, AND MAY MAINTAIN CLOUDS AND A SLIGHT CHANCE OF SHOWERS ACROSS THE I-80 CORRIDOR AND MOUNTAINS. AS TENNESSEE VALLEY HIGH PRESSURE EXITS EAST, LOW LEVEL WINDS WILL TURN SOUTHWEST TO PROVIDE A DRY WARM UP FRIDAY AND SATURDAY, PER BLEND OF RECENT GFS MOS AND NAEFS MEDIAN VALUES. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... TODAY`S MAIN CONCERN WILL BE SOUTHWEST WINDS OF 40 TO 50 KTS AT 2 KFT AGL AND HIGHER, THAT CAN RESULT IN LOW LEVEL WIND SHEAR THIS MORNING UNTIL THE SURFACE INVERSION MIXES OUT, AT WHICH TIME THESE FAST WINDS CAN CAUSE GUSTS OF 30 KTS, PER RECENT NAM MODEL PROFILES. REGARDING CLOUDS, EXPECT VFR TODAY WITH NO LOWER THAN ALTOCUMULUS CLOUDS THROUGH EARLY EVENING. FIRST PREFRONTAL SHOWERS EARLY TONIGHT CAN CAUSE STRATOCUMULUS CEILINGS BUT THESE WILL BE STILL BE MAINLY VFR. OUTLOOK...MONDAY THROUGH THURSDAY... BANDS OF SHOWERS, ASSOCIATED WITH A SLOW MOVING COLD FRONTAL SYSTEM, WILL PROVIDE PERIODS OF RESTRICTIONS MONDAY INTO TUESDAY NIGHT AREA WIDE, AND POSSIBLY WEDNESDAY ACROSS THE NORTH AND MOUNTAINS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
948 AM EST SUN NOV 13 2011 LATEST UPDATE...SHORT TERM... .SYNOPSIS...(400 AM EST SUN NOV 13 2011) LOW PRESSURE CENTERED NORTH OF LAKE SUPERIOR WILL BRING STRENGTHENING WINDS TODAY AND A FEW SHOWERS. ANOTHER LOW PRESSURE SYSTEM WILL TRACK UP THE OHIO VALLEY MONDAY. A FEW SHOWERS ASSOCIATED WITH IT MAY CLIP FAR SOUTHERN LOWER MICHIGAN. IT WILL TURN SIGNIFICANTLY COOLER WEDNESDAY AND THURSDAY. && .SHORT TERM...(948 AM EST SUN NOV 13 2011) (REST OF THIS MORNING THROUGH TUESDAY AFTERNOON) I DID SOME MINOR UPDATES TO THE ZONES FOR THE REST OF THE MORNING AND INTO THIS EVENING. MOSTLY I INCREASED POP NEAR AND NORTH OF ROUTE 10 FOR THIS AFTERNOON TO LIKELY AND CONTINUED TO POP INTO EARLY THIS EVENING. THAT WAS MOSTLY BASED ON THE LATEST DATA FROM THE RUC 12Z ...HRRR 11Z AND SREF 09Z WHICH SUGGEST THE BEST RH AND LIFT WILL BE NEAR AND NORTH OF ROUTE 10. SINCE THERE ARE SHOWERS SEEN ON RADAR (NOT REACHING THE GROUND YET) OVER SOUTHEAST MN AND THAT MATCHED NICELY THE LATEST HRRR FORECAST DATA SEEMS MORE THE REASONABLE. I STILL BELIEVE WHAT THE PREVIOUS SHIFT HAD TO SAY ABOUT THE WINDS NOT BEING ABLE TO MIX DOWN THIS AFTERNOON DUE TO THE LACK OF SOLAR RADIATION TO AID THE CAUSE. WE WILL HAVE TO WATCH THIS THROUGH SINCE 50 KNOTS IS NOT TO FAR OFF THE GROUND. A LITTLE DEEPER MIXING AND WE WILL SEE WINDS IN ADVISORY RANGE. PREVIOUS DISCUSSION FOR MONDAY INTO TUESDAY...STILL SOME FAIRLY SIGNIFICANT SHORT RANGE GUIDANCE DISCREPANCIES REGARDING THE MONDAY SYSTEM WITH 00Z NAM GUIDANCE STILL SHOWING HIGHER POPS/GREATER QPF THAN THE 00Z GFS. THIS STILL SEEMS TIED TO HOW STRONG/WHERE THE GREATEST MID LEVEL FRONTOGENETICAL FORCING WILL BE. IT IS NOTED THOUGH THAT EVEN THE 00Z GFS NOW HAS STRONG MID LEVEL FGEN ALONG THE I-94 CORRIDOR BY 18Z MON. MAV GUIDANCE POPS LOOK LOW FOR OUR SOUTHERN COUNTIES GIVEN THE MAGNITUDE OF MID LEVEL FGEN THAT IS PROGGED. WE WILL GO WITH LIKELY POPS FOR RAIN FOR OUR SOUTHERN FCST AREA MONDAY WITH CHC POPS FOR MOST OF THE REST OF OUR FCST AREA. && .LONG TERM...(400 AM EST SUN NOV 13 2011) (TUESDAY NIGHT THROUGH SATURDAY) A COLD FRONT IS FORECAST TO MOVE THROUGH SOUTHWEST LOWER MICHIGAN TUESDAY NIGHT AT THE BEGINNING OF THE LONG TERM PERIOD. THE FRONT WILL BRING MUCH COLDER AIR INTO THE REGION WHICH WILL KICK IN SOME LAKE EFFECT SNOW. THERE MAY BE A FEW LIGHT RAIN SHOWERS WITH THE PASSAGE OF THE FRONT EARLY TUESDAY NIGHT...WITH ANY PRECIPITATION SWITCHING OVER TO SNOW OVERNIGHT. MOISTURE IS NOT VERY DEEP TUESDAY NIGHT...SO NOT EXPECTING SIGNIFICANT PRECIPITATION. WEDNESDAY THROUGH THURSDAY MORNING LOOKS TO BE A COLD PERIOD WITH SOME LAKE EFFECT SNOW. DELTA T/S INCREASE WEDNESDAY NIGHT TO ALMOST 20 DEGREES C...WITH CYCLONIC FLOW IN PLACE. ONLY QUESTION MARK AT THIS POINT IS MOISTURE DEPTH. MODELS USUALLY ARE TOO LOW IN REGARD TO LAKE EFFECT MOISTURE DEPTH OUT THIS FAR IN THE FORECAST...SO SEE THE NEED TO PROBABLY RAMP UP POPS A LITTLE MORE WITH TIME. NOT OUT OF THE QUESTION TO SEE SOME LIGHT ACCUMS WEDNESDAY NIGHT TOWARD THE LAKE...MAINLY ON GRASSY AREAS. THURSDAY AFTERNOON INTO FRIDAY NIGHT SHOULD BE DRY FOR THE MOST PART AS SOUTHERLY FLOW TAKES HOLD ONCE AGAIN. HAVE SMALL POPS IN THE SOUTH FRIDAY NIGHT AS A WARM FRONT BEGINS TO TAKE SHAPE ACROSS THE AREA. BETTER CHANCES FOR SHOWERS SATURDAY AND SATURDAY NIGHT AS THE WARM FRONT LIFTS THROUGH THE REGION. TEMPERATURES WILL BE COLDER THAN NORMAL TO BEGIN THE LONG TERM PERIOD ON WEDNESDAY AND THURSDAY IN COLD NORTHWEST FLOW. TEMPERATURES WILL MODERATE TO NEAR TO SLIGHTLY ABOVE NORMAL FRIDAY AND SATURDAY IN DEVELOPING SOUTHERLY FLOW. && .AVIATION...(715 AM EST SUN NOV 13 2011) THE MAIN STORY WITH THIS MORNING/S TAF ISSUANCE IS THE WIND. SOUTH WINDS (180-200 DEGREES) OF 15-30 KNOTS ARE EXPECTED TODAY WITH SOME GUSTS REACHING THE 30-35 KNOT RANGE. THE WINDS WILL REMAIN UP ALL DAY...SUBSIDING SUBSTANTIALLY AND EVEN LOSING THE GUSTINESS AFTER 01Z OR SO THIS EVENING. A CROSS WIND IS OBVIOUSLY EXPECTED ON EAST/WEST RUNWAYS THROUGH THE DAY. VFR CEILINGS ARE EXPECTED FOR THE BULK OF FORECAST PERIOD IN THE 3500-7000FT RANGE. A PERIOD OF MVFR CEILINGS ARE POSSIBLE FROM THIS MORNING INTO THE EARLY AFTERNOON. A FEW SHOWERS ARE POSSIBLE THIS AFTERNOON AT THE NORTHERN TAF SITES OF KMKG...KGRR AND KLAN. AT THIS POINT USING VCSH WITH NO RESTRICTION TO VISIBILITY. && .MARINE...(400 AM EST SUN NOV 13 2011) SOUTHERLY GALES TO 35 KTS WILL CAUSE WAVE HEIGHTS TO BUILD TO 6 TO 10 FEET TODAY. A WEAKER PRESSURE GRADIENT TONIGHT WILL RESULT IN A GRADUAL DECREASE IN WINDS AND WAVES. && .HYDROLOGY...(400 AM EST SUN NOV 13 2011) ANY RAINFALL TODAY THROUGH TUESDAY WILL NOT BE SIGNIFICANT ENOUGH TO CAUSE ANY HYDRO ISSUES. HOWEVER THERE IS POTENTIAL FOR AROUND A HALF AN INCH OF RAIN OR SO ALONG THE I-94 CORRIDOR MONDAY. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING FOR THE ENTIRE NEARSHORE THROUGH 06Z MON. && $$ SYNOPSIS: LAURENS SHORT TERM: LAURENS WDM LONG TERM: DUKE AVIATION: DUKE MARINE: LAURENS HYDROLOGY: LAURENS
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
312 PM CST SUN NOV 13 2011 .DISCUSSION... 1008 AM CST THE CURRENT OBSERVATIONAL AND SHORT TERM MODEL TRENDS CONTINUE TO INDICATE A VERY WINDY AFTERNOON...WITH SCATTERING OF THE CLOUDS CURRENTLY OVER CHICAGOLAND. WIND GUSTS HAVE ALREADY BEEN OBSERVED TO 45 MPH IN PONTIAC...48 MPH IN CHAMPAIGN-URBANA...AND EVEN UP TO 55 MPH FURTHER SOUTH IN CENTRAL IL...WHICH IS IN THE UPSTREAM FLOW. STRONG MID-LEVEL FLOW SEEN ON THIS MORNINGS RAOBS AND PROFILES IS ATOP THE AREA AND ASSOCIATED WAVE ACROSS IOWA IS MOVING QUICKLY EAST. A 990 MB SURFACE LOW NEAR WATERLOO IS CORRELATED WITH THIS AND HAS HELPED TO BETTER DEFINE A PRE-FRONTAL TROUGH WHERE WINDS SHIFT TO SOUTHWEST AND RAPIDLY INCREASE. THE ISALLOBARIC COMPONENT IS ITS STRONGEST IN THIS AREA AS WELL. THIS TROUGH IS ALSO NEAR THE LEADING EDGE OF THE CLEARING LINE FURTHERING MIXING AS IT ENTERS THE WESTERN FORECAST AREA THROUGH NOON. THE HRRR WIND GUST FORECASTS DO SHOW THE AXIS OF 40 TO NEAR 50 MPH GUSTS COMING EAST NEAR THE INTERSTATE 39 CORRIDOR TOWARDS WATSEKA AROUND NOON MOVING INTO CHICAGO BY 1 TO 3 PM. HAVE EXPANDED WIND ADVISORY TO INCLUDE THE FAR NORTHWEST FORECAST AREA AS ROCKFORD SOUNDINGS ON THE 12Z NAM SUPPORT WIND ADVISORY SUSTAINED SPEEDS BEING REACHED SOON. MTF //PREV DISCUSSION... 327 AM CST A VERY ACTIVE PROGRESSIVE WEATHER PATTERN WILL CONTINUE FOR THE NEXT SEVERAL DAYS. FOR THE REMAINDER OF THE NIGHT AND THROUGH THE DAY SUNDAY...THE MAIN CONCERN WILL FOCUS ON WINDS. WITH A VERY STRONG PRESSURE GRADIENT IN PLACE AT THE SURFACE AND LOW LEVEL WINDS OF 50-60KT RIGHT OFF THE DECK...WINDS HAVE BEEN RATHER STRONG AND GUSTY THROUGH THE NIGHT. EXPECT THE STRONG WINDS TO CONTINUE THROUGH THE DAY SUNDAY. WITH SOME PARTIAL CLEARING EXPECTED THIS AFTERNOON...IT IS LIKELY THAT WIND GUSTS AS HIGH AS 50 MPH MAY MIX DOWN TO THE SURFACE. SO...WILL MAINTAIN THE WIND ADVISORY THAT IS IN PLACE FOR TODAY. THE ONE PORTION OF THE CWA THAT MAY ESCAPE THE STRONGEST WINDS WILL BE THE FAR NORTHWESTERN PORTIONS OF THE CWA...INCLUDING THE ROCKFORD AREA. A SHORT WAVE TRACKING OVER SRN WISCONSIN TODAY SHOULD INDUCE A WEAK SFC WAVE THAT WILL TRACK THROUGH NWRN IL AND SRN WISCONSIN. THIS MAY INTRODUCE ENOUGH BAGGINESS TO THE SFC PRESSURE GRADIENT THAT WINDS MAY NOT GET QUITE AS STRONG THERE. THE OTHER CONCERN FOR THE NEAR TERM FORECAST WILL BE THE CHANCES FOR SOME SPRINKLES OF DRIZZLE FOR THE MORNING HOURS. THE LATEST SFC ANALYSIS INDICATES A TONGUE OF ENHANCED MOISTURE FROM THE RED RIVER VALLEY...THROUGH THE MIDDLE MISSISSIPPI VALLEY AND INTO ILLINOIS...WITH SFC DEWPOINTS EARLY THIS MORNING IN THE UPPER 40S. THROUGH THE MORNING HOURS...THE STRONG SLY-SSWLY FLOW SHOULD CONTINUE TO ADVECT MORE LOW LEVEL MOISTURE ACROSS THE AREA WITH SFC DEWPOINTS REACHING INTO THE LOWER 50S. THE SHORT WAVE TRACKING ACROSS SRN WISCONSIN SHOULD PROVIDE ENOUGH FORCING TO GENERATE SOME SHOWERS FOR THE NRN TIER COUNTIES. HOWEVER...WITH THE MOISTURE CONFINED TO THE LOWER LEVELS...WITH RH TIME SECTIONS ONLY INDICATING NEAR SATURATED CONDITIONS BELOW 6KFT...AND A LAYER OF DRY AIR ABOVE...EXPECT ANY PCPN SOUTH OF THE NRN TIER COUNTIES TO BE EITHER LIGHT SPRINKLES OR DRIZZLE. BY THIS AFTERNOON...THE SHORT WAVE SHOULD PUSH OFF TO THE EAST AND AT LEAST PARTIALLY CLEARING SKIES SHOULD ALLOW FOR SOME SUNSHINE. BY SUNSET...WINDS SHOULD BEGIN TO SUBSIDE AND FOCUS OF CONCERN WILL SHIFT TO THE NEXT SYSTEM TO IMPACT THE REGION. THE MODELS ARE ADVERTISING A SRN STREAM SHORT WAVE WILL DROP OUT OF THE CENTRAL ROCKIES AND TRACK ACROSS THE SRN PLAINS. THE SYSTEM WILL QUICKLY LIFT NEWD ACROSS THE MIDDLE MISSISSIPPI VALLEY OVERNIGHT AND INTO IL/IN BY MIDDAY MONDAY. PERSISTENT SWLY SFC FLOW WILL DRAW MORE GULF MOISTURE TOWARD THE REGION. FAST SWLY FLOW ALOFT AHEAD OF THE UPPER TROUGH SHOULD SHEAR OUT THE SHORT WAVE...AND THE BEST FORCING ASSOCIATED WITH THE SYSTEM, WILL FOCUS FROM CNTRL IL TO NRN/CNTRL INDIANA. THERE SHOULD BE ADEQUATE WARM ADVECTION AND ISENTROPIC LIFT TO BRING SOME PCPN TO MUCH OF THE CWA...BUT THE HEAVIEST PCPN SHOULD BE OVER THE SERN PORTIONS...GENERALLY SOUTH AND EAST OF A LINE FROM CHICAGO TO PONTIAC. THERE IS A REMOTE CHANCE FOR SOME THUNDER WITH THIS SYSTEM...BUT WITH THE BEST FORCING SOUTH AND EAST OF THE CWA...WILL NOT CARRY ANY MENTION OF TS IN THE FORECAST. THE PATTERN WILL REMAIN VERY PROGRESSIVE INTO MIDWEEK AND THE NEXT SYSTEM OF CONCERN...A STRONG NRN STREAM SYSTEM WILL DROP ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE UPPER GREAT LAKES BY EARLY TUESDAY EVENING. THIS SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BRINGING A SHOT OF COLD AIR OUT OF CANADA. STRONG COLD ADVECTION WILL SET UP FOLLOWING THE FRONTAL PASSAGE WITH 850MB TEMPS ON THE ORDER OF -8 TO -10C SPREADING ACROSS NRN IL/IN. BY WEDNESDAY MORNING...TEMPERATURES SHOULD DROP INTO THE UPPER 20S TO LOWER 30S. AMPLE SUNSHINE SHOULD ONLY PARTIALLY COUNTERACT THE COLD ADVECTION AND TEMPERATURES WEDNESDAY WILL HAVE A HARD TIME REACTING...ONLY REACHING INTO THE UPPER 30S OR LOWER 40S. FOR THE EXTENDED FORECAST PERIOD FROM THURSDAY THROUGH SATURDAY...CONDITIONS WILL REMAIN RATHER QUIET THROUGH FRIDAY WITH MOSTLY SUNNY SKIES AND TEMPERATURES REBOUNDING BACK INTO THE LOWER 50S BY FRIDAY. THE NEXT CHANCE FOR PCPN WILL COME FRIDAY NIGHT AND SATURDAY. THE GFS AND ECMWF ARE ACTUALLY RELATIVELY CONSISTENT ON EJECTING SOME SRN STREAM ENERGY OUT OF THE CNTRL ROCKIES AND DEVELOPING A WARM FRONT ACROSS THE CNTRL PLAINS TO THE MIDDLE MISSISSIPPI VALLEY. AN OPEN GULF WOULD ALLOW FOR A DECENT RETURN FLOW OF MOISTURE OVERRUNNING THE BOUNDARY...BRINGING CHANCES OF RAIN FOR NEXT WEEKEND. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 21Z... * WINDS GUSTS THROUGH LATE AFTERNOON. * POTENTIAL FOR SOME LIGHT RAIN ON MONDAY. KJB //DISCUSSION...UPDATED 18Z... THE MAIN ISSUES BY FAR ARE THE SOUTHWEST WINDS THIS AFTERNOON. THE LATEST SURFACE ANALYSIS LATE THIS MORNING SHOWS THE TROUGH OF LOW PRESSURE NEAR THE MISSISSIPPI RIVER ACROSS EAST CENTRAL IOWA. SURFACE WINDS TO THE EAST OF THIS FEATURE HAVE REALLY JUMPED UP OVER THE PAST FEW HOURS ACROSS CENTRAL ILLINOIS AND NORTHWESTERN INDIANA AS STRONG PRESSURE FALLS ARE OCCURRING ACROSS NORTHERN ILLINOIS AHEAD OF THE TROUGH OF LOW PRESSURE. WE SHOULD BEGIN TO SEE AN INCREASE IN THE WINDS AT KORD AND KMDW HERE WITHIN THE NEXT HOUR OR TWO AS THE SURFACE TROUGH MOVES ACROSS NORTHWESTERN AND NORTH CENTRAL ILLINOIS AND STRONG PRESSURE RISES COMMENCE TO THE WEST. THEREFORE...WE ARE STILL EXPECTING THE WINDS TO BECOME MORE SOUTHWESTERLY AND INCREASE AROUND 25 TO 30 KT WITH GUSTS AROUND 40 KT DURING THE AFTERNOON. THESE WINDS WILL QUICKLY ABATE AROUND SUNSET. ANOTHER WEAK TROUGH OF LOW PRESSURE IS EXPECTED TO LIFT NORTHEASTWARD ACROSS EAST CENTRAL ILLINOIS ON MONDAY. THIS LOOKS TO BRING SOME LIGHT RAIN TO PORTIONS OF NORTHEASTERN ILLINOIS ON MONDAY MORNING. HOWEVER...THE MAJORITY OF THE RAINFALL WILL REMAIN TO THE SOUTH AND EAST OF THE TAF SITES. KJB //ORD AND MDW CONFIDENCE...UPDATED 21Z... * HIGH CONFIDENCE IN WINDS ABATING THIS EVENING. * MEDIUM CONFIDENCE IN RAIN CHANCES ON MONDAY. KJB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...VFR WITH BREEZY WEST WINDS. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR WITH SLIGHT CHANCE FOR SHRA FRIDAY NIGHT. SATURDAY...CHANCE SHRA. MDB && .MARINE... 217 PM CST IT LOOKS LIKE AN ACTIVE WEATHER PATTERN WILL BRING SEVERAL WIND EVENTS ACROSS LAKE MICHIGAN THROUGH THE UPCOMING WEEK. OUR CURRENT GALE FORCE WINDS LOOK TO CONTINUE INTO THE EVENING ACROSS THE SOUTH HALF OF THE LAKE. HOWEVER...FARTHER NORTH THE WINDS HAVE DIMINISHED BELOW GALE FORCE AND SHOULD REMAIN SUB GALE. THEREFORE...I HAVE DECIDED TO END THE GALE WARNING EARLY FOR THE NORTHERN PORTION OF THE LAKE. THE WINDS WILL REMAIN ELEVATED IN THE 10 TO 25 KT RANGE ACROSS THE LAKE FOR MUCH OF THE WEEK. HOWEVER...THERE ARE A FEW PERIODS WHERE STRONGER WINDS NEAR GALE FORCE LOOK POSSIBLE. FIRST...A STRONG COLD FRONT IS FORECAST TO MOVE OVER LAKE MICHIGAN LATE TUESDAY...AND MORE LIKELY EARLY TUESDAY EVENING. THIS LOOKS TO PRODUCE A PERIOD OF SOME GALE FORCE WINDS TUESDAY NIGHT INTO WEDNESDAY AS MUCH COLDER AIR SPILLS OVER THE LAKE AND SETS UP SOME UNSTABLE CONDITIONS. THEN LATER IN THE WEEK ANOTHER STRONG STORM SYSTEM IS EXPECTED TO MOVE ACROSS THE NORTHERN TIER OF THE COUNTY. THIS LOOKS TO SET UP SOME STRONG SOUTHWESTERLY WINDS THURSDAY NIGHT AND FRIDAY. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023- ILZ032-ILZ033-ILZ039 UNTIL 6 PM SUNDAY. IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM SUNDAY. LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
219 PM CST SUN NOV 13 2011 .DISCUSSION... 1008 AM CST THE CURRENT OBSERVATIONAL AND SHORT TERM MODEL TRENDS CONTINUE TO INDICATE A VERY WINDY AFTERNOON...WITH SCATTERING OF THE CLOUDS CURRENTLY OVER CHICAGOLAND. WIND GUSTS HAVE ALREADY BEEN OBSERVED TO 45 MPH IN PONTIAC...48 MPH IN CHAMPAIGN-URBANA...AND EVEN UP TO 55 MPH FURTHER SOUTH IN CENTRAL IL...WHICH IS IN THE UPSTREAM FLOW. STRONG MID-LEVEL FLOW SEEN ON THIS MORNINGS RAOBS AND PROFILES IS ATOP THE AREA AND ASSOCIATED WAVE ACROSS IOWA IS MOVING QUICKLY EAST. A 990 MB SURFACE LOW NEAR WATERLOO IS CORRELATED WITH THIS AND HAS HELPED TO BETTER DEFINE A PRE-FRONTAL TROUGH WHERE WINDS SHIFT TO SOUTHWEST AND RAPIDLY INCREASE. THE ISALLOBARIC COMPONENT IS ITS STRONGEST IN THIS AREA AS WELL. THIS TROUGH IS ALSO NEAR THE LEADING EDGE OF THE CLEARING LINE FURTHERING MIXING AS IT ENTERS THE WESTERN FORECAST AREA THROUGH NOON. THE HRRR WIND GUST FORECASTS DO SHOW THE AXIS OF 40 TO NEAR 50 MPH GUSTS COMING EAST NEAR THE INTERSTATE 39 CORRIDOR TOWARDS WATSEKA AROUND NOON MOVING INTO CHICAGO BY 1 TO 3 PM. HAVE EXPANDED WIND ADVISORY TO INCLUDE THE FAR NORTHWEST FORECAST AREA AS ROCKFORD SOUNDINGS ON THE 12Z NAM SUPPORT WIND ADVISORY SUSTAINED SPEEDS BEING REACHED SOON. MTF //PREV DISCUSSION... 327 AM CST A VERY ACTIVE PROGRESSIVE WEATHER PATTERN WILL CONTINUE FOR THE NEXT SEVERAL DAYS. FOR THE REMAINDER OF THE NIGHT AND THROUGH THE DAY SUNDAY...THE MAIN CONCERN WILL FOCUS ON WINDS. WITH A VERY STRONG PRESSURE GRADIENT IN PLACE AT THE SURFACE AND LOW LEVEL WINDS OF 50-60KT RIGHT OFF THE DECK...WINDS HAVE BEEN RATHER STRONG AND GUSTY THROUGH THE NIGHT. EXPECT THE STRONG WINDS TO CONTINUE THROUGH THE DAY SUNDAY. WITH SOME PARTIAL CLEARING EXPECTED THIS AFTERNOON...IT IS LIKELY THAT WIND GUSTS AS HIGH AS 50 MPH MAY MIX DOWN TO THE SURFACE. SO...WILL MAINTAIN THE WIND ADVISORY THAT IS IN PLACE FOR TODAY. THE ONE PORTION OF THE CWA THAT MAY ESCAPE THE STRONGEST WINDS WILL BE THE FAR NORTHWESTERN PORTIONS OF THE CWA...INCLUDING THE ROCKFORD AREA. A SHORT WAVE TRACKING OVER SRN WISCONSIN TODAY SHOULD INDUCE A WEAK SFC WAVE THAT WILL TRACK THROUGH NWRN IL AND SRN WISCONSIN. THIS MAY INTRODUCE ENOUGH BAGGINESS TO THE SFC PRESSURE GRADIENT THAT WINDS MAY NOT GET QUITE AS STRONG THERE. THE OTHER CONCERN FOR THE NEAR TERM FORECAST WILL BE THE CHANCES FOR SOME SPRINKLES OF DRIZZLE FOR THE MORNING HOURS. THE LATEST SFC ANALYSIS INDICATES A TONGUE OF ENHANCED MOISTURE FROM THE RED RIVER VALLEY...THROUGH THE MIDDLE MISSISSIPPI VALLEY AND INTO ILLINOIS...WITH SFC DEWPOINTS EARLY THIS MORNING IN THE UPPER 40S. THROUGH THE MORNING HOURS...THE STRONG SLY-SSWLY FLOW SHOULD CONTINUE TO ADVECT MORE LOW LEVEL MOISTURE ACROSS THE AREA WITH SFC DEWPOINTS REACHING INTO THE LOWER 50S. THE SHORT WAVE TRACKING ACROSS SRN WISCONSIN SHOULD PROVIDE ENOUGH FORCING TO GENERATE SOME SHOWERS FOR THE NRN TIER COUNTIES. HOWEVER...WITH THE MOISTURE CONFINED TO THE LOWER LEVELS...WITH RH TIME SECTIONS ONLY INDICATING NEAR SATURATED CONDITIONS BELOW 6KFT...AND A LAYER OF DRY AIR ABOVE...EXPECT ANY PCPN SOUTH OF THE NRN TIER COUNTIES TO BE EITHER LIGHT SPRINKLES OR DRIZZLE. BY THIS AFTERNOON...THE SHORT WAVE SHOULD PUSH OFF TO THE EAST AND AT LEAST PARTIALLY CLEARING SKIES SHOULD ALLOW FOR SOME SUNSHINE. BY SUNSET...WINDS SHOULD BEGIN TO SUBSIDE AND FOCUS OF CONCERN WILL SHIFT TO THE NEXT SYSTEM TO IMPACT THE REGION. THE MODELS ARE ADVERTISING A SRN STREAM SHORT WAVE WILL DROP OUT OF THE CENTRAL ROCKIES AND TRACK ACROSS THE SRN PLAINS. THE SYSTEM WILL QUICKLY LIFT NEWD ACROSS THE MIDDLE MISSISSIPPI VALLEY OVERNIGHT AND INTO IL/IN BY MIDDAY MONDAY. PERSISTENT SWLY SFC FLOW WILL DRAW MORE GULF MOISTURE TOWARD THE REGION. FAST SWLY FLOW ALOFT AHEAD OF THE UPPER TROUGH SHOULD SHEAR OUT THE SHORT WAVE...AND THE BEST FORCING ASSOCIATED WITH THE SYSTEM, WILL FOCUS FROM CNTRL IL TO NRN/CNTRL INDIANA. THERE SHOULD BE ADEQUATE WARM ADVECTION AND ISENTROPIC LIFT TO BRING SOME PCPN TO MUCH OF THE CWA...BUT THE HEAVIEST PCPN SHOULD BE OVER THE SERN PORTIONS...GENERALLY SOUTH AND EAST OF A LINE FROM CHICAGO TO PONTIAC. THERE IS A REMOTE CHANCE FOR SOME THUNDER WITH THIS SYSTEM...BUT WITH THE BEST FORCING SOUTH AND EAST OF THE CWA...WILL NOT CARRY ANY MENTION OF TS IN THE FORECAST. THE PATTERN WILL REMAIN VERY PROGRESSIVE INTO MIDWEEK AND THE NEXT SYSTEM OF CONCERN...A STRONG NRN STREAM SYSTEM WILL DROP ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE UPPER GREAT LAKES BY EARLY TUESDAY EVENING. THIS SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BRINGING A SHOT OF COLD AIR OUT OF CANADA. STRONG COLD ADVECTION WILL SET UP FOLLOWING THE FRONTAL PASSAGE WITH 850MB TEMPS ON THE ORDER OF -8 TO -10C SPREADING ACROSS NRN IL/IN. BY WEDNESDAY MORNING...TEMPERATURES SHOULD DROP INTO THE UPPER 20S TO LOWER 30S. AMPLE SUNSHINE SHOULD ONLY PARTIALLY COUNTERACT THE COLD ADVECTION AND TEMPERATURES WEDNESDAY WILL HAVE A HARD TIME REACTING...ONLY REACHING INTO THE UPPER 30S OR LOWER 40S. FOR THE EXTENDED FORECAST PERIOD FROM THURSDAY THROUGH SATURDAY...CONDITIONS WILL REMAIN RATHER QUIET THROUGH FRIDAY WITH MOSTLY SUNNY SKIES AND TEMPERATURES REBOUNDING BACK INTO THE LOWER 50S BY FRIDAY. THE NEXT CHANCE FOR PCPN WILL COME FRIDAY NIGHT AND SATURDAY. THE GFS AND ECMWF ARE ACTUALLY RELATIVELY CONSISTENT ON EJECTING SOME SRN STREAM ENERGY OUT OF THE CNTRL ROCKIES AND DEVELOPING A WARM FRONT ACROSS THE CNTRL PLAINS TO THE MIDDLE MISSISSIPPI VALLEY. AN OPEN GULF WOULD ALLOW FOR A DECENT RETURN FLOW OF MOISTURE OVERRUNNING THE BOUNDARY...BRINGING CHANCES OF RAIN FOR NEXT WEEKEND. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WINDS TURNING SOUTHWEST BEHIND A COOL FRONT WITH GUSTS INCREASING TO AROUND 40 KT WITH SOME BRIEF GUSTS TO AROUND 45 KT POSSIBLE THIS AFTERNOON. * POTENTIAL FOR SOME LIGHT RAIN ON MONDAY. KJB //DISCUSSION...UPDATED 18Z... THE MAIN ISSUES BY FAR ARE THE SOUTHWEST WINDS THIS AFTERNOON. THE LATEST SURFACE ANALYSIS LATE THIS MORNING SHOWS THE TROUGH OF LOW PRESSURE NEAR THE MISSISSIPPI RIVER ACROSS EAST CENTRAL IOWA. SURFACE WINDS TO THE EAST OF THIS FEATURE HAVE REALLY JUMPED UP OVER THE PAST FEW HOURS ACROSS CENTRAL ILLINOIS AND NORTHWESTERN INDIANA AS STRONG PRESSURE FALLS ARE OCCURRING ACROSS NORTHERN ILLINOIS AHEAD OF THE TROUGH OF LOW PRESSURE. WE SHOULD BEGIN TO SEE AN INCREASE IN THE WINDS AT KORD AND KMDW HERE WITHIN THE NEXT HOUR OR TWO AS THE SURFACE TROUGH MOVES ACROSS NORTHWESTERN AND NORTH CENTRAL ILLINOIS AND STRONG PRESSURE RISES COMMENCE TO THE WEST. THEREFORE...WE ARE STILL EXPECTING THE WINDS TO BECOME MORE SOUTHWESTERLY AND INCREASE AROUND 25 TO 30 KT WITH GUSTS AROUND 40 KT DURING THE AFTERNOON. THESE WINDS WILL QUICKLY ABATE AROUND SUNSET. ANOTHER WEAK TROUGH OF LOW PRESSURE IS EXPECTED TO LIFT NORTHEASTWARD ACROSS EAST CENTRAL ILLINOIS ON MONDAY. THIS LOOKS TO BRING SOME LIGHT RAIN TO PORTIONS OF NORTHEASTERN ILLINOIS ON MONDAY MORNING. HOWEVER...THE MAJORITY OF THE RAINFALL WILL REMAIN TO THE SOUTH AND EAST OF THE TAF SITES. KJB //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WINDS TURNING SOUTHWESTERLY BEHIND A COOL FRONT WITH GUSTS TO 40 KT...MEDIUM CONFIDENCE THAT THERE WILL BE SOME GUSTS TO AROUND 45 KT. * MEDIUM CONFIDENCE IN RAIN CHANCES ON MONDAY. KJB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...VFR WITH BREEZY WEST WINDS. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR WITH SLIGHT CHANCE FOR SHRA FRIDAY NIGHT. SATURDAY...CHANCE SHRA. MDB && .MARINE... 217 PM CST IT LOOKS LIKE AN ACTIVE WEATHER PATTERN WILL BRING SEVERAL WIND EVENTS ACROSS LAKE MICHIGAN THROUGH THE UPCOMING WEEK. OUR CURRENT GALE FORCE WINDS LOOK TO CONTINUE INTO THE EVENING ACROSS THE SOUTH HALF OF THE LAKE. HOWEVER...FARTHER NORTH THE WINDS HAVE DIMINISHED BELOW GALE FORCE AND SHOULD REMAIN SUB GALE. THEREFORE...I HAVE DECIDED TO END THE GALE WARNING EARLY FOR THE NORTHERN PORTION OF THE LAKE. THE WINDS WILL REMAIN ELEVATED IN THE 10 TO 25 KT RANGE ACROSS THE LAKE FOR MUCH OF THE WEEK. HOWEVER...THERE ARE A FEW PERIODS WHERE STRONGER WINDS NEAR GALE FORCE LOOK POSSIBLE. FIRST...A STRONG COLD FRONT IS FORECAST TO MOVE OVER LAKE MICHIGAN LATE TUESDAY...AND MORE LIKELY EARLY TUESDAY EVENING. THIS LOOKS TO PRODUCE A PERIOD OF SOME GALE FORCE WINDS TUESDAY NIGHT INTO WEDNESDAY AS MUCH COLDER AIR SPILLS OVER THE LAKE AND SETS UP SOME UNSTABLE CONDITIONS. THEN LATER IN THE WEEK ANOTHER STRONG STORM SYSTEM IS EXPECTED TO MOVE ACROSS THE NORTHERN TIER OF THE COUNTY. THIS LOOKS TO SET UP SOME STRONG SOUTHWESTERLY WINDS THURSDAY NIGHT AND FRIDAY. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023- ILZ032-ILZ033-ILZ039 UNTIL 6 PM SUNDAY. IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM SUNDAY. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878 UNTIL 9 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1153 AM CST SUN NOV 13 2011 .DISCUSSION... 1008 AM CST THE CURRENT OBSERVATIONAL AND SHORT TERM MODEL TRENDS CONTINUE TO INDICATE A VERY WINDY AFTERNOON...WITH SCATTERING OF THE CLOUDS CURRENTLY OVER CHICAGOLAND. WIND GUSTS HAVE ALREADY BEEN OBSERVED TO 45 MPH IN PONTIAC...48 MPH IN CHAMPAIGN-URBANA...AND EVEN UP TO 55 MPH FURTHER SOUTH IN CENTRAL IL...WHICH IS IN THE UPSTREAM FLOW. STRONG MID-LEVEL FLOW SEEN ON THIS MORNINGS RAOBS AND PROFILES IS ATOP THE AREA AND ASSOCIATED WAVE ACROSS IOWA IS MOVING QUICKLY EAST. A 990 MB SURFACE LOW NEAR WATERLOO IS CORRELATED WITH THIS AND HAS HELPED TO BETTER DEFINE A PRE-FRONTAL TROUGH WHERE WINDS SHIFT TO SOUTHWEST AND RAPIDLY INCREASE. THE ISALLOBARIC COMPONENT IS ITS STRONGEST IN THIS AREA AS WELL. THIS TROUGH IS ALSO NEAR THE LEADING EDGE OF THE CLEARING LINE FURTHERING MIXING AS IT ENTERS THE WESTERN FORECAST AREA THROUGH NOON. THE HRRR WIND GUST FORECASTS DO SHOW THE AXIS OF 40 TO NEAR 50 MPH GUSTS COMING EAST NEAR THE INTERSTATE 39 CORRIDOR TOWARDS WATSEKA AROUND NOON MOVING INTO CHICAGO BY 1 TO 3 PM. HAVE EXPANDED WIND ADVISORY TO INCLUDE THE FAR NORTHWEST FORECAST AREA AS ROCKFORD SOUNDINGS ON THE 12Z NAM SUPPORT WIND ADVISORY SUSTAINED SPEEDS BEING REACHED SOON. MTF //PREV DISCUSSION... 327 AM CST A VERY ACTIVE PROGRESSIVE WEATHER PATTERN WILL CONTINUE FOR THE NEXT SEVERAL DAYS. FOR THE REMAINDER OF THE NIGHT AND THROUGH THE DAY SUNDAY...THE MAIN CONCERN WILL FOCUS ON WINDS. WITH A VERY STRONG PRESSURE GRADIENT IN PLACE AT THE SURFACE AND LOW LEVEL WINDS OF 50-60KT RIGHT OFF THE DECK...WINDS HAVE BEEN RATHER STRONG AND GUSTY THROUGH THE NIGHT. EXPECT THE STRONG WINDS TO CONTINUE THROUGH THE DAY SUNDAY. WITH SOME PARTIAL CLEARING EXPECTED THIS AFTERNOON...IT IS LIKELY THAT WIND GUSTS AS HIGH AS 50 MPH MAY MIX DOWN TO THE SURFACE. SO...WILL MAINTAIN THE WIND ADVISORY THAT IS IN PLACE FOR TODAY. THE ONE PORTION OF THE CWA THAT MAY ESCAPE THE STRONGEST WINDS WILL BE THE FAR NORTHWESTERN PORTIONS OF THE CWA...INCLUDING THE ROCKFORD AREA. A SHORT WAVE TRACKING OVER SRN WISCONSIN TODAY SHOULD INDUCE A WEAK SFC WAVE THAT WILL TRACK THROUGH NWRN IL AND SRN WISCONSIN. THIS MAY INTRODUCE ENOUGH BAGGINESS TO THE SFC PRESSURE GRADIENT THAT WINDS MAY NOT GET QUITE AS STRONG THERE. THE OTHER CONCERN FOR THE NEAR TERM FORECAST WILL BE THE CHANCES FOR SOME SPRINKLES OF DRIZZLE FOR THE MORNING HOURS. THE LATEST SFC ANALYSIS INDICATES A TONGUE OF ENHANCED MOISTURE FROM THE RED RIVER VALLEY...THROUGH THE MIDDLE MISSISSIPPI VALLEY AND INTO ILLINOIS...WITH SFC DEWPOINTS EARLY THIS MORNING IN THE UPPER 40S. THROUGH THE MORNING HOURS...THE STRONG SLY-SSWLY FLOW SHOULD CONTINUE TO ADVECT MORE LOW LEVEL MOISTURE ACROSS THE AREA WITH SFC DEWPOINTS REACHING INTO THE LOWER 50S. THE SHORT WAVE TRACKING ACROSS SRN WISCONSIN SHOULD PROVIDE ENOUGH FORCING TO GENERATE SOME SHOWERS FOR THE NRN TIER COUNTIES. HOWEVER...WITH THE MOISTURE CONFINED TO THE LOWER LEVELS...WITH RH TIME SECTIONS ONLY INDICATING NEAR SATURATED CONDITIONS BELOW 6KFT...AND A LAYER OF DRY AIR ABOVE...EXPECT ANY PCPN SOUTH OF THE NRN TIER COUNTIES TO BE EITHER LIGHT SPRINKLES OR DRIZZLE. BY THIS AFTERNOON...THE SHORT WAVE SHOULD PUSH OFF TO THE EAST AND AT LEAST PARTIALLY CLEARING SKIES SHOULD ALLOW FOR SOME SUNSHINE. BY SUNSET...WINDS SHOULD BEGIN TO SUBSIDE AND FOCUS OF CONCERN WILL SHIFT TO THE NEXT SYSTEM TO IMPACT THE REGION. THE MODELS ARE ADVERTISING A SRN STREAM SHORT WAVE WILL DROP OUT OF THE CENTRAL ROCKIES AND TRACK ACROSS THE SRN PLAINS. THE SYSTEM WILL QUICKLY LIFT NEWD ACROSS THE MIDDLE MISSISSIPPI VALLEY OVERNIGHT AND INTO IL/IN BY MIDDAY MONDAY. PERSISTENT SWLY SFC FLOW WILL DRAW MORE GULF MOISTURE TOWARD THE REGION. FAST SWLY FLOW ALOFT AHEAD OF THE UPPER TROUGH SHOULD SHEAR OUT THE SHORT WAVE...AND THE BEST FORCING ASSOCIATED WITH THE SYSTEM, WILL FOCUS FROM CNTRL IL TO NRN/CNTRL INDIANA. THERE SHOULD BE ADEQUATE WARM ADVECTION AND ISENTROPIC LIFT TO BRING SOME PCPN TO MUCH OF THE CWA...BUT THE HEAVIEST PCPN SHOULD BE OVER THE SERN PORTIONS...GENERALLY SOUTH AND EAST OF A LINE FROM CHICAGO TO PONTIAC. THERE IS A REMOTE CHANCE FOR SOME THUNDER WITH THIS SYSTEM...BUT WITH THE BEST FORCING SOUTH AND EAST OF THE CWA...WILL NOT CARRY ANY MENTION OF TS IN THE FORECAST. THE PATTERN WILL REMAIN VERY PROGRESSIVE INTO MIDWEEK AND THE NEXT SYSTEM OF CONCERN...A STRONG NRN STREAM SYSTEM WILL DROP ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE UPPER GREAT LAKES BY EARLY TUESDAY EVENING. THIS SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BRINGING A SHOT OF COLD AIR OUT OF CANADA. STRONG COLD ADVECTION WILL SET UP FOLLOWING THE FRONTAL PASSAGE WITH 850MB TEMPS ON THE ORDER OF -8 TO -10C SPREADING ACROSS NRN IL/IN. BY WEDNESDAY MORNING...TEMPERATURES SHOULD DROP INTO THE UPPER 20S TO LOWER 30S. AMPLE SUNSHINE SHOULD ONLY PARTIALLY COUNTERACT THE COLD ADVECTION AND TEMPERATURES WEDNESDAY WILL HAVE A HARD TIME REACTING...ONLY REACHING INTO THE UPPER 30S OR LOWER 40S. FOR THE EXTENDED FORECAST PERIOD FROM THURSDAY THROUGH SATURDAY...CONDITIONS WILL REMAIN RATHER QUIET THROUGH FRIDAY WITH MOSTLY SUNNY SKIES AND TEMPERATURES REBOUNDING BACK INTO THE LOWER 50S BY FRIDAY. THE NEXT CHANCE FOR PCPN WILL COME FRIDAY NIGHT AND SATURDAY. THE GFS AND ECMWF ARE ACTUALLY RELATIVELY CONSISTENT ON EJECTING SOME SRN STREAM ENERGY OUT OF THE CNTRL ROCKIES AND DEVELOPING A WARM FRONT ACROSS THE CNTRL PLAINS TO THE MIDDLE MISSISSIPPI VALLEY. AN OPEN GULF WOULD ALLOW FOR A DECENT RETURN FLOW OF MOISTURE OVERRUNNING THE BOUNDARY...BRINGING CHANCES OF RAIN FOR NEXT WEEKEND. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WINDS TURNING SOUTHWEST BEHIND A COOL FRONT WITH GUSTS INCREASING TO AROUND 40 KT WITH SOME BRIEF GUSTS TO AROUND 45 KT POSSIBLE THIS AFTERNOON. * POTENTIAL FOR SOME LIGHT RAIN ON MONDAY. KJB //DISCUSSION...UPDATED 18Z... THE MAIN ISSUES BY FAR ARE THE SOUTHWEST WINDS THIS AFTERNOON. THE LATEST SURFACE ANALYSIS LATE THIS MORNING SHOWS THE TROUGH OF LOW PRESSURE NEAR THE MISSISSIPPI RIVER ACROSS EAST CENTRAL IOWA. SURFACE WINDS TO THE EAST OF THIS FEATURE HAVE REALLY JUMPED UP OVER THE PAST FEW HOURS ACROSS CENTRAL ILLINOIS AND NORTHWESTERN INDIANA AS STRONG PRESSURE FALLS ARE OCCURRING ACROSS NORTHERN ILLINOIS AHEAD OF THE TROUGH OF LOW PRESSURE. WE SHOULD BEGIN TO SEE AN INCREASE IN THE WINDS AT KORD AND KMDW HERE WITHIN THE NEXT HOUR OR TWO AS THE SURFACE TROUGH MOVES ACROSS NORTHWESTERN AND NORTH CENTRAL ILLINOIS AND STRONG PRESSURE RISES COMMENCE TO THE WEST. THEREFORE...WE ARE STILL EXPECTING THE WINDS TO BECOME MORE SOUTHWESTERLY AND INCREASE AROUND 25 TO 30 KT WITH GUSTS AROUND 40 KT DURING THE AFTERNOON. THESE WINDS WILL QUICKLY ABATE AROUND SUNSET. ANOTHER WEAK TROUGH OF LOW PRESSURE IS EXPECTED TO LIFT NORTHEASTWARD ACROSS EAST CENTRAL ILLINOIS ON MONDAY. THIS LOOKS TO BRING SOME LIGHT RAIN TO PORTIONS OF NORTHEASTERN ILLINOIS ON MONDAY MORNING. HOWEVER...THE MAJORITY OF THE RAINFALL WILL REMAIN TO THE SOUTH AND EAST OF THE TAF SITES. KJB //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WINDS TURNING SOUTHWESTERLY BEHIND A COOL FRONT WITH GUSTS TO 40 KT...MEDIUM CONFIDENCE THAT THERE WILL BE SOME GUSTS TO AROUND 45 KT. * MEDIUM CONFIDENCE IN RAIN CHANCES ON MONDAY. KJB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...VFR WITH BREEZY WEST WINDS. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR WITH SLIGHT CHANCE FOR SHRA FRIDAY NIGHT. SATURDAY...CHANCE SHRA. MDB && .MARINE... 305 AM CST LITTLE CHANGE TO OVERALL FORECAST FOR TODAY AND TONIGHT WITH DEEP LOW PRESSURE SPINNING FROM SOUTHEAST MANITOBA INTO WESTERN ONTARIO WHILE HIGH PRESSURE SITS OFF THE SOUTHEAST U.S. COAST. A COMBINATION OF A TIGHT PRESSURE GRADIENT AND VERY STRONG LOW LEVEL JET JUST ABOVE THE SURFACE HAS RESULTED IN SOUTHERLY WIND GUSTS NEAR OR JUST OVER GALE FORCE ACROSS THE LAKE EARLY THIS MORNING. THE LOW WILL DEEPEN AND CONTINUE TO MOVE NORTHEASTWARD ACROSS HUDSON BAY TONIGHT AND MONDAY. A SHARP COLD FRONT WILL CROSS THE LAKE TODAY BRINGING IN A PERIOD OF COOL ADVECTION THIS AFTERNOON AND THIS EVENING. STILL EXPECT GALES TO CONTINUE ACROSS THE LAKE AND PICK UP ACROSS THE SOUTH HALF OF THE LAKE TODAY BEFORE SETTLING DOWN THIS EVENING. WILL CONTINUE WITH 35 KT MENTION NORTH WITH GALES INCREASING TO 45 KT ON THE SOUTH HALF OF THE LAKE THIS AFTERNOON. THERE APPEARS TO BE A SHORT SEVERAL HOUR WINDOW WHERE GUSTS COULD REACH 50 KT AS THE COLD FRONT PASSES MIDDAY OR SO BUT THIS LOOKS TO BE INFREQUENT IF IT CAN OCCUR. STABILITY MAY BE ABLE TO MITIGATE SOME OF THE MAXIMUM GUSTS BUT LOW LEVEL WINDS OF 40 KT ARE PRESENT STARTING AROUND 500 FT SO 40-45 KT GUSTS SHOULD STILL OCCUR. THE ISOLATED STORM FORCE GUSTS MAY BE MORE LIKELY...ALBEIT STILL A LOW CHANCE...CLOSER TO THE INDIANA AND ILLINOIS SHORES AS MIXING SHOULD BE OF GREATER DEPTH AS AIRMASS ADVECTS OFF OF LAND. WINDS WILL DROP BELOW GALE FORCE SOMETIME THIS EVENING BUT SPEEDS WILL STAY ELEVATED WITH A SLIGHT INCREASE MONDAY AFTERNOON AS A WEAK TROUGH CROSSES THE AREA. ANOTHER LOW WILL THEN TRACK EASTWARD ACROSS THE AREA TUESDAY LEADING TO ANOTHER GOOD CHANCE FOR AT LEAST LOW END GALES TUESDAY AFTERNOON AND EVENING. HIGH PRESSURE WILL THEN BUILD IN WEDNESDAY BUT THE PRESSURE GRADIENT REMAINS RATHER TIGHT SO WINDS WILL REMAIN ELEVATED UNTIL SOMETIME THURSDAY. A SERIES OF LOWS WILL CROSS THE LAKE INTO THE WEEKEND BRINGING PERIODIC INCREASES IN WINDS AND WAVES AND SOME POSSIBILITY FOR AT LEAST LOW END GALES. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023- ILZ032-ILZ033-ILZ039 UNTIL 6 PM SUNDAY. IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM SUNDAY. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878 UNTIL 9 PM SUNDAY. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1024 AM CST SUN NOV 13 2011 .DISCUSSION... 1008 AM CST THE CURRENT OBSERVATIONAL AND SHORT TERM MODEL TRENDS CONTINUE TO INDICATE A VERY WINDY AFTERNOON...WITH SCATTERING OF THE CLOUDS CURRENTLY OVER CHICAGOLAND. WIND GUSTS HAVE ALREADY BEEN OBSERVED TO 45 MPH IN PONTIAC...48 MPH IN CHAMPAIGN-URBANA...AND EVEN UP TO 55 MPH FURTHER SOUTH IN CENTRAL IL...WHICH IS IN THE UPSTREAM FLOW. STRONG MID-LEVEL FLOW SEEN ON THIS MORNINGS RAOBS AND PROFILES IS ATOP THE AREA AND ASSOCIATED WAVE ACROSS IOWA IS MOVING QUICKLY EAST. A 990 MB SURFACE LOW NEAR WATERLOO IS CORRELATED WITH THIS AND HAS HELPED TO BETTER DEFINE A PRE-FRONTAL TROUGH WHERE WINDS SHIFT TO SOUTHWEST AND RAPIDLY INCREASE. THE ISALLOBARIC COMPONENT IS ITS STRONGEST IN THIS AREA AS WELL. THIS TROUGH IS ALSO NEAR THE LEADING EDGE OF THE CLEARING LINE FURTHERING MIXING AS IT ENTERS THE WESTERN FORECAST AREA THROUGH NOON. THE HRRR WIND GUST FORECASTS DO SHOW THE AXIS OF 40 TO NEAR 50 MPH GUSTS COMING EAST NEAR THE INTERSTATE 39 CORRIDOR TOWARDS WATSEKA AROUND NOON MOVING INTO CHICAGO BY 1 TO 3 PM. HAVE EXPANDED WIND ADVISORY TO INCLUDE THE FAR NORTHWEST FORECAST AREA AS ROCKFORD SOUNDINGS ON THE 12Z NAM SUPPORT WIND ADVISORY SUSTAINED SPEEDS BEING REACHED SOON. MTF && .PREV DISCUSSION... 327 AM CST A VERY ACTIVE PROGRESSIVE WEATHER PATTERN WILL CONTINUE FOR THE NEXT SEVERAL DAYS. FOR THE REMAINDER OF THE NIGHT AND THROUGH THE DAY SUNDAY...THE MAIN CONCERN WILL FOCUS ON WINDS. WITH A VERY STRONG PRESSURE GRADIENT IN PLACE AT THE SURFACE AND LOW LEVEL WINDS OF 50-60KT RIGHT OFF THE DECK...WINDS HAVE BEEN RATHER STRONG AND GUSTY THROUGH THE NIGHT. EXPECT THE STRONG WINDS TO CONTINUE THROUGH THE DAY SUNDAY. WITH SOME PARTIAL CLEARING EXPECTED THIS AFTERNOON...IT IS LIKELY THAT WIND GUSTS AS HIGH AS 50 MPH MAY MIX DOWN TO THE SURFACE. SO...WILL MAINTAIN THE WIND ADVISORY THAT IS IN PLACE FOR TODAY. THE ONE PORTION OF THE CWA THAT MAY ESCAPE THE STRONGEST WINDS WILL BE THE FAR NORTHWESTERN PORTIONS OF THE CWA...INCLUDING THE ROCKFORD AREA. A SHORT WAVE TRACKING OVER SRN WISCONSIN TODAY SHOULD INDUCE A WEAK SFC WAVE THAT WILL TRACK THROUGH NWRN IL AND SRN WISCONSIN. THIS MAY INTRODUCE ENOUGH BAGGINESS TO THE SFC PRESSURE GRADIENT THAT WINDS MAY NOT GET QUITE AS STRONG THERE. THE OTHER CONCERN FOR THE NEAR TERM FORECAST WILL BE THE CHANCES FOR SOME SPRINKLES OF DRIZZLE FOR THE MORNING HOURS. THE LATEST SFC ANALYSIS INDICATES A TONGUE OF ENHANCED MOISTURE FROM THE RED RIVER VALLEY...THROUGH THE MIDDLE MISSISSIPPI VALLEY AND INTO ILLINOIS...WITH SFC DEWPOINTS EARLY THIS MORNING IN THE UPPER 40S. THROUGH THE MORNING HOURS...THE STRONG SLY-SSWLY FLOW SHOULD CONTINUE TO ADVECT MORE LOW LEVEL MOISTURE ACROSS THE AREA WITH SFC DEWPOINTS REACHING INTO THE LOWER 50S. THE SHORT WAVE TRACKING ACROSS SRN WISCONSIN SHOULD PROVIDE ENOUGH FORCING TO GENERATE SOME SHOWERS FOR THE NRN TIER COUNTIES. HOWEVER...WITH THE MOISTURE CONFINED TO THE LOWER LEVELS...WITH RH TIME SECTIONS ONLY INDICATING NEAR SATURATED CONDITIONS BELOW 6KFT...AND A LAYER OF DRY AIR ABOVE...EXPECT ANY PCPN SOUTH OF THE NRN TIER COUNTIES TO BE EITHER LIGHT SPRINKLES OR DRIZZLE. BY THIS AFTERNOON...THE SHORT WAVE SHOULD PUSH OFF TO THE EAST AND AT LEAST PARTIALLY CLEARING SKIES SHOULD ALLOW FOR SOME SUNSHINE. BY SUNSET...WINDS SHOULD BEGIN TO SUBSIDE AND FOCUS OF CONCERN WILL SHIFT TO THE NEXT SYSTEM TO IMPACT THE REGION. THE MODELS ARE ADVERTISING A SRN STREAM SHORT WAVE WILL DROP OUT OF THE CENTRAL ROCKIES AND TRACK ACROSS THE SRN PLAINS. THE SYSTEM WILL QUICKLY LIFT NEWD ACROSS THE MIDDLE MISSISSIPPI VALLEY OVERNIGHT AND INTO IL/IN BY MIDDAY MONDAY. PERSISTENT SWLY SFC FLOW WILL DRAW MORE GULF MOISTURE TOWARD THE REGION. FAST SWLY FLOW ALOFT AHEAD OF THE UPPER TROUGH SHOULD SHEAR OUT THE SHORT WAVE...AND THE BEST FORCING ASSOCIATED WITH THE SYSTEM, WILL FOCUS FROM CNTRL IL TO NRN/CNTRL INDIANA. THERE SHOULD BE ADEQUATE WARM ADVECTION AND ISENTROPIC LIFT TO BRING SOME PCPN TO MUCH OF THE CWA...BUT THE HEAVIEST PCPN SHOULD BE OVER THE SERN PORTIONS...GENERALLY SOUTH AND EAST OF A LINE FROM CHICAGO TO PONTIAC. THERE IS A REMOTE CHANCE FOR SOME THUNDER WITH THIS SYSTEM...BUT WITH THE BEST FORCING SOUTH AND EAST OF THE CWA...WILL NOT CARRY ANY MENTION OF TS IN THE FORECAST. THE PATTERN WILL REMAIN VERY PROGRESSIVE INTO MIDWEEK AND THE NEXT SYSTEM OF CONCERN...A STRONG NRN STREAM SYSTEM WILL DROP ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE UPPER GREAT LAKES BY EARLY TUESDAY EVENING. THIS SYSTEM WILL DRAG A STRONG COLD FRONT ACROSS THE AREA BRINGING A SHOT OF COLD AIR OUT OF CANADA. STRONG COLD ADVECTION WILL SET UP FOLLOWING THE FRONTAL PASSAGE WITH 850MB TEMPS ON THE ORDER OF -8 TO -10C SPREADING ACROSS NRN IL/IN. BY WEDNESDAY MORNING...TEMPERATURES SHOULD DROP INTO THE UPPER 20S TO LOWER 30S. AMPLE SUNSHINE SHOULD ONLY PARTIALLY COUNTERACT THE COLD ADVECTION AND TEMPERATURES WEDNESDAY WILL HAVE A HARD TIME REACTING...ONLY REACHING INTO THE UPPER 30S OR LOWER 40S. FOR THE EXTENDED FORECAST PERIOD FROM THURSDAY THROUGH SATURDAY...CONDITIONS WILL REMAIN RATHER QUIET THROUGH FRIDAY WITH MOSTLY SUNNY SKIES AND TEMPERATURES REBOUNDING BACK INTO THE LOWER 50S BY FRIDAY. THE NEXT CHANCE FOR PCPN WILL COME FRIDAY NIGHT AND SATURDAY. THE GFS AND ECMWF ARE ACTUALLY RELATIVELY CONSISTENT ON EJECTING SOME SRN STREAM ENERGY OUT OF THE CNTRL ROCKIES AND DEVELOPING A WARM FRONT ACROSS THE CNTRL PLAINS TO THE MIDDLE MISSISSIPPI VALLEY. AN OPEN GULF WOULD ALLOW FOR A DECENT RETURN FLOW OF MOISTURE OVERRUNNING THE BOUNDARY...BRINGING CHANCES OF RAIN FOR NEXT WEEKEND. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * SOUTH WINDS GUSTING TO AROUND 30 KT THROUGH THE MORNING. * WINDS TURNING SOUTHWEST BEHIND A COOL FRONT WITH GUSTS INCREASING TO AROUND 40 KT WITH SOME BRIEF GUSTS TO AROUND 45 KT POSSIBLE THIS AFTERNOON. * MVFR CIGS THIS MORNING EXITING TO THE EAST AROUND MIDDAY. MDB/KJB //DISCUSSION...UPDATED 12Z... LOW PRESSURE TROUGH STILL TO THE WEST OF THE TERMINALS ACROSS CENTRAL IOWA WITH THE MAIN SURFACE LOW ACROSS WESTERN ONTARIO. SURFACE PRESSURE GRADIENT REMAINS TIGHT WITH WINDS INCREASING TO AROUND 50 KT IN THE FIRST 2000 FT OF THE ATMOSPHERE. SURFACE WIND GUSTS HAVE SUBSIDED SOMEWHAT LIKELY DUE TO STRENGTHENED LOW LEVEL INVERSION BUT SPEEDS WILL BE INCREASING THIS MORNING AND ESPECIALLY THIS AFTERNOON. HIGH CIRRUS NOW STREAMING OVERHEAD WITH SCT-BKN PATCHES OF LOWER END VFR CLOUD COVER LINGERING AS WELL. THERE IS STILL SUPPORT FOR NEW MVFR/VFR CIG DEVELOPMENT AS THE LOW PRESSURE MOVES CLOSER THIS MORNING BUT HAVE SEEN MINIMAL EVIDENCE SHOWING THIS HAS BEGUN. WILL CONTINUE WITH A PERIOD OF MVFR CIGS THIS MORNING THOUGH THIS MAY NEED TO BE ADJUSTED. SOME GUIDANCE ALSO SHOWS IFR DEVELOPMENT BUT AM HAVING A TOUGH TIME FINDING MUCH SUPPORT FOR THIS. WINDS ARE THE NEXT CONCERN. WITH VERY STRONG WINDS JUST ABOVE THE SURFACE GUSTS SHOULD BEGIN TO INCREASE AFTER DAYBREAK THANKS TO INCREASED MIXING BUT NEW CLOUD DEVELOPMENT MAY ACT TO SUPPRESS THE GUSTS SOMEWHAT. WILL CONTINUE WITH IDEA OF 25 TO 30 KT GUSTS THIS MORNING THOUGH THESE WOULD NEED TO BE INCREASED IF LOWER CLOUD COVER DOES NOT MATERIALIZE. THE SURFACE TROUGH/FRONT WILL SWEEP ACROSS THE AREA AROUND MIDDAY TURNING WINDS MORE SOUTHWESTERLY AND SCOURING OUT ANY LOW CLOUD COVER. WITH COOL AIR MOVING IN ABOVE THE SURFACE AND CLEARING SKIES WIND GUSTS SHOULD INCREASE MARKEDLY THIS AFTERNOON...ESPECIALLY AT THE CHICAGO/NW INDIANA TERMINALS. WILL GO WITH PREVAILING GUSTS OF 40 KT AT ORD AND MDW THOUGH THERE IS SOME CHANCE FOR BRIEF GUSTS AROUND 45 KT ALONG AND BEHIND THE FRONT. GUSTS AT RFD SHOULD BE IN THE 35 KT RANGE THANKS TO A WEAKER PRESSURE GRADIENT. WINDS WILL DIMINISH THIS EVENING AND BECOME LIGHT OVERNIGHT WITH VFR EXPECTED. MDB //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN SOUTH WINDS GUSTING TO AROUND 30 KT THROUGH THE MORNING. * HIGH CONFIDENCE IN WINDS TURNING SOUTHWESTERLY BEHIND A COOL FRONT AROUND MIDDAY WITH GUSTS TO 40 KT...MEDIUM CONFIDENCE THAT THERE WILL BE SOME GUSTS TO AROUND 45 KT. * HIGH CONFIDENCE IN CIGS IMPROVING THIS AFTERNOON. MDB/KJB //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...VFR WITH BREEZY WEST WINDS. WEDNESDAY...VFR. THURSDAY...VFR. FRIDAY...VFR WITH SLIGHT CHANCE FOR SHRA FRIDAY NIGHT. SATURDAY...CHANCE SHRA. MDB && .MARINE... 305 AM CST LITTLE CHANGE TO OVERALL FORECAST FOR TODAY AND TONIGHT WITH DEEP LOW PRESSURE SPINNING FROM SOUTHEAST MANITOBA INTO WESTERN ONTARIO WHILE HIGH PRESSURE SITS OFF THE SOUTHEAST U.S. COAST. A COMBINATION OF A TIGHT PRESSURE GRADIENT AND VERY STRONG LOW LEVEL JET JUST ABOVE THE SURFACE HAS RESULTED IN SOUTHERLY WIND GUSTS NEAR OR JUST OVER GALE FORCE ACROSS THE LAKE EARLY THIS MORNING. THE LOW WILL DEEPEN AND CONTINUE TO MOVE NORTHEASTWARD ACROSS HUDSON BAY TONIGHT AND MONDAY. A SHARP COLD FRONT WILL CROSS THE LAKE TODAY BRINGING IN A PERIOD OF COOL ADVECTION THIS AFTERNOON AND THIS EVENING. STILL EXPECT GALES TO CONTINUE ACROSS THE LAKE AND PICK UP ACROSS THE SOUTH HALF OF THE LAKE TODAY BEFORE SETTLING DOWN THIS EVENING. WILL CONTINUE WITH 35 KT MENTION NORTH WITH GALES INCREASING TO 45 KT ON THE SOUTH HALF OF THE LAKE THIS AFTERNOON. THERE APPEARS TO BE A SHORT SEVERAL HOUR WINDOW WHERE GUSTS COULD REACH 50 KT AS THE COLD FRONT PASSES MIDDAY OR SO BUT THIS LOOKS TO BE INFREQUENT IF IT CAN OCCUR. STABILITY MAY BE ABLE TO MITIGATE SOME OF THE MAXIMUM GUSTS BUT LOW LEVEL WINDS OF 40 KT ARE PRESENT STARTING AROUND 500 FT SO 40-45 KT GUSTS SHOULD STILL OCCUR. THE ISOLATED STORM FORCE GUSTS MAY BE MORE LIKELY...ALBEIT STILL A LOW CHANCE...CLOSER TO THE INDIANA AND ILLINOIS SHORES AS MIXING SHOULD BE OF GREATER DEPTH AS AIRMASS ADVECTS OFF OF LAND. WINDS WILL DROP BELOW GALE FORCE SOMETIME THIS EVENING BUT SPEEDS WILL STAY ELEVATED WITH A SLIGHT INCREASE MONDAY AFTERNOON AS A WEAK TROUGH CROSSES THE AREA. ANOTHER LOW WILL THEN TRACK EASTWARD ACROSS THE AREA TUESDAY LEADING TO ANOTHER GOOD CHANCE FOR AT LEAST LOW END GALES TUESDAY AFTERNOON AND EVENING. HIGH PRESSURE WILL THEN BUILD IN WEDNESDAY BUT THE PRESSURE GRADIENT REMAINS RATHER TIGHT SO WINDS WILL REMAIN ELEVATED UNTIL SOMETIME THURSDAY. A SERIES OF LOWS WILL CROSS THE LAKE INTO THE WEEKEND BRINGING PERIODIC INCREASES IN WINDS AND WAVES AND SOME POSSIBILITY FOR AT LEAST LOW END GALES. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WIND ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023- ILZ032-ILZ033-ILZ039 UNTIL 6 PM SUNDAY. IN...WIND ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 6 PM SUNDAY. LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742- LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878 UNTIL 9 PM SUNDAY. && $$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
102 PM EST SUN NOV 13 2011 LATEST UPDATE...AVIATION... .SYNOPSIS...(400 AM EST SUN NOV 13 2011) LOW PRESSURE CENTERED NORTH OF LAKE SUPERIOR WILL BRING STRENGTHENING WINDS TODAY AND A FEW SHOWERS. ANOTHER LOW PRESSURE SYSTEM WILL TRACK UP THE OHIO VALLEY MONDAY. A FEW SHOWERS ASSOCIATED WITH IT MAY CLIP FAR SOUTHERN LOWER MICHIGAN. IT WILL TURN SIGNIFICANTLY COOLER WEDNESDAY AND THURSDAY. && .SHORT TERM...(948 AM EST SUN NOV 13 2011) (REST OF THIS MORNING THROUGH TUESDAY AFTERNOON) I DID SOME MINOR UPDATES TO THE ZONES FOR THE REST OF THE MORNING AND INTO THIS EVENING. MOSTLY I INCREASED POP NEAR AND NORTH OF ROUTE 10 FOR THIS AFTERNOON TO LIKELY AND CONTINUED TO POP INTO EARLY THIS EVENING. THAT WAS MOSTLY BASED ON THE LATEST DATA FROM THE RUC 12Z ...HRRR 11Z AND SREF 09Z WHICH SUGGEST THE BEST RH AND LIFT WILL BE NEAR AND NORTH OF ROUTE 10. SINCE THERE ARE SHOWERS SEEN ON RADAR (NOT REACHING THE GROUND YET) OVER SOUTHEAST MN AND THAT MATCHED NICELY THE LATEST HRRR FORECAST DATA SEEMS MORE THE REASONABLE. I STILL BELIEVE WHAT THE PREVIOUS SHIFT HAD TO SAY ABOUT THE WINDS NOT BEING ABLE TO MIX DOWN THIS AFTERNOON DUE TO THE LACK OF SOLAR RADIATION TO AID THE CAUSE. WE WILL HAVE TO WATCH THIS THROUGH SINCE 50 KNOTS IS NOT TO FAR OFF THE GROUND. A LITTLE DEEPER MIXING AND WE WILL SEE WINDS IN ADVISORY RANGE. PREVIOUS DISCUSSION FOR MONDAY INTO TUESDAY...STILL SOME FAIRLY SIGNIFICANT SHORT RANGE GUIDANCE DISCREPANCIES REGARDING THE MONDAY SYSTEM WITH 00Z NAM GUIDANCE STILL SHOWING HIGHER POPS/GREATER QPF THAN THE 00Z GFS. THIS STILL SEEMS TIED TO HOW STRONG/WHERE THE GREATEST MID LEVEL FRONTOGENETICAL FORCING WILL BE. IT IS NOTED THOUGH THAT EVEN THE 00Z GFS NOW HAS STRONG MID LEVEL FGEN ALONG THE I-94 CORRIDOR BY 18Z MON. MAV GUIDANCE POPS LOOK LOW FOR OUR SOUTHERN COUNTIES GIVEN THE MAGNITUDE OF MID LEVEL FGEN THAT IS PROGGED. WE WILL GO WITH LIKELY POPS FOR RAIN FOR OUR SOUTHERN FCST AREA MONDAY WITH CHC POPS FOR MOST OF THE REST OF OUR FCST AREA. && .LONG TERM...(400 AM EST SUN NOV 13 2011) (TUESDAY NIGHT THROUGH SATURDAY) A COLD FRONT IS FORECAST TO MOVE THROUGH SOUTHWEST LOWER MICHIGAN TUESDAY NIGHT AT THE BEGINNING OF THE LONG TERM PERIOD. THE FRONT WILL BRING MUCH COLDER AIR INTO THE REGION WHICH WILL KICK IN SOME LAKE EFFECT SNOW. THERE MAY BE A FEW LIGHT RAIN SHOWERS WITH THE PASSAGE OF THE FRONT EARLY TUESDAY NIGHT...WITH ANY PRECIPITATION SWITCHING OVER TO SNOW OVERNIGHT. MOISTURE IS NOT VERY DEEP TUESDAY NIGHT...SO NOT EXPECTING SIGNIFICANT PRECIPITATION. WEDNESDAY THROUGH THURSDAY MORNING LOOKS TO BE A COLD PERIOD WITH SOME LAKE EFFECT SNOW. DELTA T/S INCREASE WEDNESDAY NIGHT TO ALMOST 20 DEGREES C...WITH CYCLONIC FLOW IN PLACE. ONLY QUESTION MARK AT THIS POINT IS MOISTURE DEPTH. MODELS USUALLY ARE TOO LOW IN REGARD TO LAKE EFFECT MOISTURE DEPTH OUT THIS FAR IN THE FORECAST...SO SEE THE NEED TO PROBABLY RAMP UP POPS A LITTLE MORE WITH TIME. NOT OUT OF THE QUESTION TO SEE SOME LIGHT ACCUMS WEDNESDAY NIGHT TOWARD THE LAKE...MAINLY ON GRASSY AREAS. THURSDAY AFTERNOON INTO FRIDAY NIGHT SHOULD BE DRY FOR THE MOST PART AS SOUTHERLY FLOW TAKES HOLD ONCE AGAIN. HAVE SMALL POPS IN THE SOUTH FRIDAY NIGHT AS A WARM FRONT BEGINS TO TAKE SHAPE ACROSS THE AREA. BETTER CHANCES FOR SHOWERS SATURDAY AND SATURDAY NIGHT AS THE WARM FRONT LIFTS THROUGH THE REGION. TEMPERATURES WILL BE COLDER THAN NORMAL TO BEGIN THE LONG TERM PERIOD ON WEDNESDAY AND THURSDAY IN COLD NORTHWEST FLOW. TEMPERATURES WILL MODERATE TO NEAR TO SLIGHTLY ABOVE NORMAL FRIDAY AND SATURDAY IN DEVELOPING SOUTHERLY FLOW. && .AVIATION...(102 PM EST SUN NOV 13 2011) GUSTY WINDS WILL CONTINUE THIS AFTERNOON AS LOW LEVEL MOISTURE STREAMS INTO THE REGION. CIGS WILL LIKELY REMAIN AROUND 3K FT THIS AFTERNOON BEFORE RISING TONIGHT. SHOWERS POSSIBLE NEAR KMKG THIS AFTERNOON. VFR CEILINGS ARE EXPECTED FOR THE BULK OF FORECAST PERIOD IN THE 3500-7000FT RANGE. A PERIOD OF MVFR CEILINGS ARE POSSIBLE FROM THIS MORNING INTO THE EARLY AFTERNOON. A FEW SHOWERS ARE POSSIBLE THIS AFTERNOON AT THE NORTHERN TAF SITES OF KMKG...KGRR AND KLAN. AT THIS POINT USING VCSH WITH NO RESTRICTION TO VISIBILITY. && .MARINE...(400 AM EST SUN NOV 13 2011) SOUTHERLY GALES TO 35 KTS WILL CAUSE WAVE HEIGHTS TO BUILD TO 6 TO 10 FEET TODAY. A WEAKER PRESSURE GRADIENT TONIGHT WILL RESULT IN A GRADUAL DECREASE IN WINDS AND WAVES. && .HYDROLOGY...(400 AM EST SUN NOV 13 2011) ANY RAINFALL TODAY THROUGH TUESDAY WILL NOT BE SIGNIFICANT ENOUGH TO CAUSE ANY HYDRO ISSUES. HOWEVER THERE IS POTENTIAL FOR AROUND A HALF AN INCH OF RAIN OR SO ALONG THE I-94 CORRIDOR MONDAY. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING FOR THE ENTIRE NEARSHORE THROUGH 06Z MON. && $$ SYNOPSIS: LAURENS SHORT TERM: LAURENS WDM LONG TERM: DUKE AVIATION: 93 MARINE: LAURENS HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1037 AM MST SUN NOV 13 2011 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH TUESDAY... UPDATED THE FORECAST TO RAISE THE TEMPERATURES A FEW DEGREES THIS MORNING. ADDED SOME SLIGHT CHANCE POPS ACROSS OUR WESTERN ZONES FOR LIGHT SNOW AND RAIN THIS MORNING...ZORTMAN WAS REPORTING LIGHT SNOW AROUND 0945. ADJUSTED THE SKY COVER DOWN SOME AS BREAKS IN THE CLOUD COVER ARE SHOWING UP ON THE VISIBLE SATELLITE LOOP. THE OVERALL SITUATION IS STILL NORTHWEST FLOW WITH EMBEDDED SHORTWAVES MOVING ACROSS EASTERN MONTANA. THE PROBLEM IS THE LACK OF MID AND UPPER LEVEL MOISTURE PRESENT IN THE ATMOSPHERE WHEN THESE SHORTWAVE CROSS EASTERN MONTANA. A FEW OF THE MODELS ARE ALSO STARTING TO BACK OFF OF SEEING PRECIPITATION FOR THIS AFTERNOON AND EVENING. THE NAM HAS DRIED NORTHEAST MONTANA OUT FOR THE REST OF THE DAY WITH A SLIGHT CHANCE OF SNOW CLIPPING EXTREME NORTHEAST MONTANA. THE GFS IS STILL TRYING TO BRING SCATTERED SNOW SHOWERS THROUGH NEMONT THIS AFTERNOON WITH THE NORTHWEST FLOW ALOFT. LOOKING AT THE HRRR MODEL IT LOOKS MORE LIKE THE NAM FOR THE REST OF THE DAY. MY THOUGHTS ON TODAY ARE TO LEAVE THE SLIGHT CHANCE OF LIGHT RAIN OR SNOW IN THE FORECAST ACROSS THE REGION. ANYTHING PRECIPITATION THAT DOES HAPPEN WILL BE VERY LIGHT AND WILL NOT BE MUCH MORE THEN A TRACE. THERE IS STILL A CHANCE OF SOME LIGHT SNOW AS A COLD FRONT CROSS EASTERN MONTANA FROM NORTH TO SOUTH EARLY MONDAY MORNING INTO MONDAY AFTERNOON. RSMITH PREVIOUS DISCUSSION...GUSTY NORTHWEST WINDS AT 15 TO 25 MPH WILL QUICKLY DIMINISH SHORTLY AFTER SUNSET THIS EVENING. THUS THE LAKE WIND ADVISORY EXPIRATION TIME OF 6 PM LOOKS ON TRACK. THE MAIN TROUGH BODY WILL CLEAR THE REGION TO THE SOUTH AND EAST BY EARLY EVENING AS WELL. A LARGE REGION OF LOW STRATUS CURRENTLY EXISTS ACROSS SOUTHERN ALBERTA AND SOUTHERN SASKATCHEWAN. EXPECT THIS CLOUD COVER TO PUSH IN THIS EVENING AND OVERNIGHT WHILE THE UPPER LEVEL FLOW STAYS NORTHWEST. WEAK DISTURBANCES IN THIS FLOW COULD DRIVE SOME LIGHT SHOWERS...IN ADDITION SOME LIGHT FLURRIES OR DRIZZLE IS POSSIBLE OUT OF THE STRATUS. SUNDAY INTO SUNDAY NIGHT THE UNSETTLED NORTHWEST FLOW ALOFT WILL CONTINUE OVER NORTHEAST MONTANA. GIVEN THIS FLOW PATTERN AND LINGERING LOW LEVEL MOISTURE CAN NOT RULE OUT A FEW PERIODS OF LIGHT PRECIPITATION...THUS KEPT MENTION IN THE FORECAST. GUSTY NORTHWEST WINDS LOOK TO RETURN LATE SUNDAY MORNING...AND ANOTHER LAKE WIND ADVISORY LOOKS LIKE A GOOD BET. MONDAY WILL BRING ANOTHER COLD FRONTAL PASSAGE...AND BETTER POTENTIAL FOR PRECIPITATION. BRISK GUSTY NORTHWEST WINDS WILL ACCOMPANY THE FRONT...AND WILL LIKELY REACH THE 20 TO 30 MPH RANGE WITH A FEW GUSTS APPROACHING 40 MPH AT TIMES. TEMPERATURES WILL ALSO BE ON THE COOL SIDE BEHIND THE FRONT...STRUGGLING TO CLIMB OUT OF THE 30S AT MOST LOCATIONS. GILCHRIST .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... TUESDAY NIGHT THROUGH WEDNESDAY... THE LONG TERM BEGINS WITH A SYNOPTIC SET UP OF A TROUGH RUNNING DOWN NUNAVUT TO MANITOBA AND A RIDGE RUNNING UP THE COAST OF THE PACIFIC NORTHWEST. MONTANA WILL BE WEDGED BETWEEN THESE TWO FEATURES ON THE COLDER SIDE OF NORTHWEST FLOW PATTERN. CONDITIONS SHOULD BE RELATIVELY DRY THROUGH THIS PERIOD WITH PARTLY CLOUDY SKIES AND TEMPERATURES JUST A LITTLE BELOW NORMAL. WEDNESDAY THROUGH THURSDAY... AS THE RIDGE CROSS THE INTERMOUNTAIN WEST IT WILL BEGIN EXTENDING A WEAK CHINOOK OVER THE REGION WITH VARIABLY CLOUDY SKIES AND WARMING CONDITIONS TO NEAR OR JUST ABOVE NORMAL. THURSDAY NIGHT THROUGH FRIDAY NIGHT... THE CHINOOK SHUTS OFF AND THE FIRST WAVE OF TRUE ARCTIC AIR THAT HAD BEEN GATHERING OVER THE ALASKAN NORTH SLOPE BEGINS TO FILTER INTO THE REGION. A STRONG DROP OFF IN TEMPERATURES ALONG WITH MOSTLY CLOUDY SKIES CAN BE ANTICIPATED AS THE BOUNDARY SETS ITSELF UP WELL TO THE SOUTH OVER NORTHERN WYOMING. AT THIS POINT... A TROUGH WILL DIG INTO THE WEST COAST OF THE CONUS AND BEGIN LEVELING WARMER MOIST PACIFIC AIR UP INTO THE MID LEVELS ON SOUTHWEST FLOW. SATURDAY THROUGH SUNDAY... WHILE MODELS CAN CHANGE THIS FAR OUT A HIGHER THAN NORMAL SIGNAL IS BEING SENT AS THE GFS AND EC MATCH AND STANDARD DEVIATION OF THE ENSEMBLE SPREADS IS RATHER LOW. PACIFIC MOISTURE WILL RIDE UP AND OVER THE DEVELOPED ARCTIC BOUNDARY AND GENERATE A FAIRLY STRONG SNOW STORM SOMEWHERE BETWEEN WYOMING... EASTERN MONTANA... AND THE DAKOTAS. AT THE MOMENT BEST GUESS IS FOR THE BULK OF THE SNOW TO BE TO THE SOUTH. BUT WITH FUTURE RUNS THIS STORM COULD EASILY DRIFT NORTH. CONFIDENCE IN THE STORM IS SURPRISINGLY WELL ABOVE AVERAGE THIS FAR OUT BUT PLACEMENT IS NOT YET CERTAIN AS THE ARCTIC FRONT IS SURE TO NEED ADJUSTING. GAH && .AVIATION... VFR WITH A MID LEVEL BROKEN TO OVERCAST DECK. WINDS WILL BE OUT OF THE WEST AROUND 15 TO 20 KTS GUSTING UP TO 30 KTS FOR SOME PLACES. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... LAKE WIND ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR FORT PECK LAKE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1216 PM CST SUN NOV 13 2011 .UPDATE...MIDDAY SURFACE ANALYSIS INDICATES A COLD FRONT EXTENDING ACROSS THE UPPER MISSISSIPPI VALLEY INTO PORTIONS OF THE CENTRAL PLAINS...WITH FROPA COMPLETE ACROSS OUR ENTIRE CWA AS OF 18Z. THE LOW LEVEL WIND FIELD REMAINS FROM THE WEST/NORTHWEST AS A RESULT...WITH THE STRONGEST WINDS NEAR 20KTS LOCATED ACROSS OUR EAST IN AN AREA JUST BEHIND THE FRONT WHERE LOW LEVEL PRESSURE RISES ARE THE GREATEST. SURFACE WINDS ARE DIMINISHING ACROSS OUR WEST HOWEVER AS THE LOW LEVEL PRESSURE GRADIENT FORCE CONTINUES WEAKENING FARTHER BEHIND THE FRONT. SCATTERED TO BROKEN HIGH LEVEL CLOUDS AND LOW LEVEL CAA WILL LIKELY KEEP AFTERNOON TEMPERATURES FROM RISING VERY FAR THIS AFTERNOON. GOING FORECAST HAD THIS WELL IN HAND WITH HIGHS IN THE MID 50S TO NEAR 60...THUS NO MAJOR CHANGES MADE TO FORECAST AFTERNOON TEMPERATURES. DOWN SLOPE WEST/NORTHWEST LOW LEVEL FLOW WILL PERSIST THROUGH THE AFTERNOON WITH PBL MIXING EXPECTED TO RISE TO NEAR 800MB THIS AFTERNOON. RUC AND LAPS PROXIMITY SOUNDINGS FROM ACROSS THE CWA SUGGEST THE DRIEST AIR IS LOCATED CLOSER TO THE SURFACE TODAY...WITH SLIGHTLY MORE MOISTURE EXISTING ABOVE 900MB. LAYER-AVERAGED DEW POINTS FROM 800MB PER THE NAM DO NOT SUGGEST MUCH OF DROP OFF IN AFTERNOON SURFACE DEW POINTS AS A RESULT...HOWEVER SURFACE ANALYSIS DOES INDICATE MUCH LOWER SURFACE DEW POINT ACROSS WESTERN NEBRASKA BEGINNING TO ADVECT INTO OUR AREA...THUS THERE MAY STILL BE A DROP IN AFTERNOON DEW POINTS...PERHAPS FALLING INTO THE LOW TO MID 20 DEGREE RANGE. THESE DEW POINTS AND FORECAST AFTERNOON TEMPERATURES ONLY YIELD AFTERNOON RH VALUES IN THE 23%-25% RANGE ACROSS OUR WEST...AND WITH SURFACE WINDS EXPECTED TO CONTINUE DIMINISHING THROUGH THE AFTERNOON HOURS...DO NOT CURRENTLY EXPECT RFW ISSUANCE WILL BE REQUIRED THIS AFTERNOON. && .AVIATION...18Z KGRI TAF. VFR CONDITIONS TO CONTINUE AT KGRI THROUGH THE NEXT 24 HOURS. SURFACE WINDS WILL VARY FROM THE NORTHWEST TO SOUTHWEST THROUGH THE TAF PERIOD...DECREASING IN INTENSITY TODAY THROUGH TONIGHT. HIGH LEVEL CLOUDS NEAR 18000FT AGL WILL LIKELY PERSIST AT THE TERMINAL...WITH CEILINGS LOWERING TO NEAR 9000FT AGL 00Z-09Z. VISIBILITY RESTRICTIONS ARE NOT EXPECTED AT KGRI THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 358 AM CST SUN NOV 13 2011/ SHORT TERM...TODAY THROUGH TUESDAY NIGHT. SHORTWAVE TROUGH WAS CROSSING THE CENTRAL PLAINS DURING THE PRE DAWN HOURS. THE ASSOCIATED COLD FRONT WAS PRETTY MUCH THROUGH OUR CWA AS OF 09Z. THREE HOUR PRESSURE RISES BEHIND THE FRONT AVERAGED 1-3MB...AND SOME IMPRESSIVE WIND GUSTS OVER 50MPH WERE OBSERVED IN PORTIONS OF WESTERN NEBRASKA EARLIER...WITH GUSTS OVER 30 MPH STILL OCCURRING ATTM. THE SURFACE GRADIENT WILL REMAIN TIGHT THROUGH ABOUT MID MORNING...RESULTING IN GUSTY WEST TO NORTHWESTERLY WINDS...BEFORE RELAXING DURING THE AFTERNOON. TEMPS WILL BE COOLER TODAY FOLLOWING FROPA WITH TEMPS MAINLY RETURNING TO THE 50S TO AROUND 60F. MUCH DRIER AIR ADVECTS IN FROM THE WEST THIS MORNING...AND WILL RESULT IN LOW RELATIVE HUMIDITY VALUES. CURRENT FORECAST LOW RELATIVE HUMIDITY VALUES ARE FORECAST IN THE LOW/MID 20S AND AS WINDS DECREASE WITH TIME TODAY...MEETING FIRE WEATHER WARNING CRITERIA TODAY LOOKS TO BE BORDERLINE. HEADING INTO THE EVENING...A 150KT JET STREAK NOSES ACROSS CENTRAL KANSAS AND A SUBTLE MID LEVEL SHORTWAVE TROUGH CROSSES THE CENTRAL PLAINS REGION. OVERALL FEELING IS THAT WE WILL MAINLY SEE JUST AN INCREASE IN MID LEVEL CLOUD COVER VS PCPN WITH FORECAST SOUNDINGS AND CROSS SECTIONS INDICATING RATHER DRY LOW LEVELS. HOWEVER WITH SPRINKLE WORDING ALREADY IN THERE...AND GFS/ECMWF SHOWING SOME LIGHT QPF...WILL LEAVE AS IS BUT LIMIT TIME FRAME TO BETWEEN 00Z AND 06Z MONDAY...WITH LIFT DIMINISHING AND CLOUDS DECREASING AFTER 06Z. DRY CONDITIONS ARE FORECAST THROUGH THE REMAINDER OF THE SHORT TERM PERIOD. WESTERLY FLOW ALOFT AND IN THE LLVLS WILL KEEP TEMPS ABOVE SEASONAL NORMALS FOR HIGHS IN THE 50S TO LOWER 60S. MONDAY NIGHT...A TROUGH CROSSES THE NORTHERN PLAINS REGION...SENDING A COLD FRONTAL BOUNDARY SOUTH THROUGH THE CENTRAL PLAINS BY TUESDAY MORNING. THE GFS IS DEEPER WITH TROUGH/COLD AIR ADVECTION ON TUESDAY COMPARED TO OTHER MODELS...WITH THE ECMWF THE MILDEST AND THE NAM IN BETWEEN THE TWO. WILL COMPROMISE FOR NOW AMONG MODELS WITH TEMPS CLOSER TO THE NAM SOLUTION. SURFACE HIGH PRESSURE BUILDS IN BEHIND THE FRONT AND TEMPS LOOK TO DROP INTO THE 20S FOR LOWS IN THE COOLER/DRY AIRMASS. LONG TERM...WEDNESDAY THROUGH SATURDAY. THE GFS SWINGS THE TROUGH THROUGH THE PLAINS QUICKER THAN ECMWF WEDNESDAY...HOWEVER EITHER WAY STILL A COOLER DAY WITH H85 TEMPS NEAR -5C AND TEMPS ONLY AVERAGING IN THE 40S FOR HIGHS. HEIGHTS RISE BEHIND THE DEPARTING TROUGH THRU THE WORKWEEK...WITH FLOW TRANSITIONING SOUTHWESTERLY BY SATURDAY AS AN UPPER TROUGH REACHES THE SOUTHWEST CONUS. MODELS ARE INDICATING SOME PCPN IN THE VCNTY OF OUR CWA SATURDAY IN THE WAA PATTERN BUT CONFIDENCE IS NOT HIGH ON LOCATION OF THIS JUST YET AND WILL MAINTAIN DRY FCST FOR NOW. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE/AVIATION...BRYANT