Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 12/30/11


AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
425 PM EST WED DEC 28 2011 .SHORT TERM... TONIGHT THROUGH THURSDAY NIGHT PAIR OF WEAK CLIPPER SYSTEMS TO IMPACT THE AREA IN THE SHORT TERM. WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS DEPICTING LEAD SHORT WAVE OVER SOUTHERN MANITOBA AND MOVING INTO WESTERN ONTARIO. THIS FEATURE EXPECTED TO WEAKEN/SHEAR OUT IN FAST MOVING NW FLOW PATTERN AS IT DROPS DOWN INTO THE NORTHERN GREAT LAKES TONIGHT/THU AM. RESULT SHOULD BE BETTER CHANCES FOR PRECIP TO REMAIN NORTH OF THE AREA WHERE BETTER FORCING AND MOISTURE WILL BE PRESENT...BUT CLOSE ENOUGH TO MAINTAIN SMALL CHANCE POPS FOR NORTHERN TWO THIRDS OF CWA. MODELS INDICATING DECENT SFC/LOW LEVEL RESPONSE WITH THIS FIRST SHORT WAVE RESULTING IN GOOD WAA IN ADVANCE OF THIS SYSTEM WHICH WILL HAVE TEMPS SLOWLY RISING AFTER MIDNIGHT TONIGHT AND ALSO BRING PRECIP TYPE INTO QUESTION. FCST SOUNDINGS SHOWING DECENT ELEVATED WARM LAYER AND MORE FAVORABLE PROFILES IN SUPPORT OF LIQUID PRECIP...AND WHILE 12Z SOUNDINGS FROM KOAX AND KSGF LEND CREDENCE TO THIS SCENARIO...STILL NOT CONVINCED THAT MUCH LOW LEVEL WARMING WILL BE REALIZED WITH FAST MOVING SYSTEM SO WILL KEEP WITH RA/SN MIX IN WX GRIDS ATTM. 140KT JET COMING ONSHORE IN PACIFIC NW THIS MORNING WILL DRIVE SECOND SHORT WAVE INTO THE AREA QUICKLY BEHIND THE FIRST THURSDAY NIGHT. THIS WAVE WILL DIG FURTHER SOUTH AND BRING BETTER FORCING AND MOISTURE INTO THE FORECAST AREA...AS CURRENTLY REFLECTED IN GRIDS WITH LOW TO HIGH CHANCE POPS FROM EAST TO WEST ACROSS THE CWA. STILL LIKE THE NOTION OF A SMALL WINDOW OF DRY WX BETWEEN THESE TWO SYSTEMS SO WILL STAY WITH DRY FCST 00-06Z FRI. WITH RELATIVELY WARMER AIR IN PLACE...WILL TREND WX GRIDS TOWARD LIQUID PRECIP WITH ALL RAIN IN THE SOUTHERN TIER BUT STAY WITH MIX ELSEWHERE GIVEN NOCTURNAL TIMING. ABOVE NORMAL TEMPS THROUGH THE PERIOD AND GUIDANCE REASONABLE IN HANDLING THIS. && .LONG TERM... FRIDAY THROUGH WEDNESDAY AN UPPER LEVEL DISTURBANCE WILL TRACK SOUTHEASTWARD FROM SOUTHERN ALBERTA/SASKATCHEWAN THURSDAY MORNING INTO THE MIDWEST BY FRIDAY MORNING. MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT WITH THE TRACK OF THE WAVE AND THE ATTENDANT SURFACE LOW...HOWEVER MINOR TIMING DIFFERENCES EXIST. WENT AHEAD AND BUMPED POPS UP TO LIKELY ACROSS THE NORTHERN HALF OF THE CWA FRIDAY MORNING...ALONG THE PREFERRED TRACK OF THE SURFACE LOW. PRECIPITATION TYPE CONCERNS REMAIN AN ISSUE WITH THIS SYSTEM. THERMAL PROFILES PER MODELS SOUNDINGS SUGGEST MOSTLY RAIN WITH THIS SYSTEM THROUGH THE DAY FRIDAY...WITH COLDER AIR ARRIVING LATE AFTERNOON...INTRODUCING A MIX AND EVENTUAL CHANGEOVER TO SNOW AND PRECIPITATION TAPERS OFF. HOWEVER...GIVEN THE TIMING DIFFERENCES BETWEEN MODELS....AND SLIGHT MODEL DIFFERENCES WITH THE TRACK OF THE SYSTEM...PREFERRED TO LEAVE A RAIN/SNOW MENTION FOR FRIDAY ACROSS THE NORTH AND FRIDAY NIGHT EVERYWHERE. WILL DEFER REFINING OF P-TYPE TO NEXT FORECAST CYCLE AND HOPEFULLY MORE CONSISTENT MODEL SOLUTIONS. NO MAJOR CHANGES TO TEMPERATURES FRIDAY AND FRIDAY NIGHT. SYSTEM EXITS THE REGION BY SATURDAY MORNING...AND HIGH PRESSURE BUILDS INTO THE REGION FROM THE SOUTHWEST. CONDITIONS WILL BE DRY THROUGH THE DAY SATURDAY...BEFORE A SIGNIFICANT PATTERN CHANGE ARRIVES ACROSS THE REGION. UPPER LEVEL TROF WILL DIG SOUTHEAST FROM CANADA INTO THE EASTERN CONUS SUNDAY INTO EARLY NEXT WEEK...AND ALONG WITH IT A POLAR AIR MASS...WITH MODEL H85 TEMPS APPROACHING -20C BY TUESDAY ACROSS THE REGION. SFC LOW PRESSURE WILL MOVE ACROSS THE NORTHERN TIER INTO THE GREAT LAKES REGION BY BY SUNDAY. MODELS DIFFER WITH THE EXACT TRACK OF THE LOW...WITH THE GFS SUPPORTING A FASTER MORE SOUTHERLY TRACK...AND THE ECMWF A BIT SLOWER WITH A MORE NORTHERLY TRACK. CONSEQUENTLY...THE GFS SUPPORTS STRONGER FORCING ACROSS THE REGION SATURDAY NIGHT INTO SUNDAY...WHILE THE ECMWF SUPPORTS WEAKER FORCING MOVING INTO THE AREA DURING THE DAY SUNDAY. ALLBLEND PROCEDURE INTRODUCED SLIGHT CHANCE POPS ON SATURDAY NIGHT...WHICH HAVE BEEN RETAINED FOR COLLABORATIVE PURPOSES. FEEL THAT THE GFS IS SLIGHTLY TO FAST WITH THE TRACK OF THE SYSTEM AND BEST PRECIP CHANCES WILL BE DURING THE DAY SUNDAY. COLD AIR WILL THEN FILTER INTO THE REGION BEHIND THE FRONT...WHICH WILL BE THE CATALYST FOR LAKE EFFECT SNOW LATE SUNDAY THROUGH TUESDAY ACROSS THE AREA. MODELS ARE IN DECENT AGREEMENT OF A NW TO NORTHERLY FETCH AND ADEQUATE MOISTURE PROFILE...WITH LAKE SFC TO H85 DELTA TS IN EXCESS OF 20C...AND LAKE SFC TO H7 DELTA TS IN THE MID TO UPPER 20C RANGE. WENT AHEAD AND RAISED POPS SUNDAY NIGHT INTO TUESDAY TO HIGH CHANCE ACROSS LAKE EFFECT PREFERRED AREAS. NO MAJOR CHANGES TO TEMPERATURES...AS THE ALLBLEND SOLUTIONS HAVE CAUGHT ON TO COLDER TEMPERATURES WITH THE ARRIVAL OF THE POLAR AIR MASS.&& .AVIATION... / 18Z TAFS / LATEST OBS INDICATING THAT MVFR LAKE EFFECT CLOUDS STILL IMPACTING KSBN. DIFFICULT TO DETERMINE TRENDS FROM VIS SAT GIVEN MID LEVEL DECK ON TOP...BUT WILL EXTEND A TEMPO MVFR FOR FIRST HOUR OF THIS CYCLE AT KSBN THEN BELIEVE WINDS BACKING TO MORE SW LATER THIS AFTERNOON SHOULD SHIFT LAKE EFFECT CLOUDS TO THE NORTH AND EAST. WEAK CLIPPER SYSTEM MOVING DOWN TONIGHT WILL KEEP MVFR DECK IN PLACE OVER BOTH SITES AND ALSO CONTINUE BACKING OF WINDS TO MORE SOUTHERLY AND INCREASE TO 10-15KTS TOWARD THE END OF THE PERIOD. UNCERTAINTY OF PRECIP DEVELOPMENT WITH THIS SYSTEM WILL PRECLUDE ANY MENTION FOR THIS TAF CYCLE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...LOGSDON LONG TERM...NG AVIATION...LOGSDON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
513 PM CST THU DEC 29 2011 .AVIATION... FOR THE 00Z TAF ISSUANCE... 21Z RUN SUGGESTING THAT A FEW SPRINKLES OR EVEN A BRIEF SHOWER WILL BE POSSIBLE NEAR THE HAYS AREA THROUGH 02Z BASED ON LOCATION OF THE UPPER LEVEL JET AND INCREASING MID LEVEL INSTABILITY AHEAD OF AN UPPER LEVEL TROUGH. FURTHER SOUTH THE LATEST 21Z RUC AND 18Z NAM SOUNDINGS CONTINUE TO SUPPORT ONLY MID-HIGH LEVEL MOISTURE CROSSING THIS REGION. AS A RESULT WILL BRIEFLY MENTION A VCSH IN THE TAFS FOR A COUPLE OF HOURS AT HAYS WHILE LEAVING THE FORECAST DRY FURTHER SOUTH WITH VFR CIGS THROUGH THE FIRST HALF OF THE NIGHT. AS THIS UPPER TROUGH PASSES...A COLD FRONT WILL MOVE SOUTH ACROSS NORTH CENTRAL AND SOUTHWEST KANSAS. 22Z SURFACE OBSERVATIONS INDICATING THAT THE FRONT WAS BEGINNING TO MOVE INTO NORTHWEST KANSAS WHICH WAS QUICKER THAN WHAT THE 18Z NAM MODEL SUGGESTED. 19Z HRRR AND 21Z RUC40 WERE CLOSER TO THE 22Z FRONTAL LOCATION SO WILL LEAN TOWARDS THE FASTER HRRR/RUC ON TIMING OF THE FROPA EARLY TONIGHT. WILL ALSO FAVOR THE STRONGER WINDS THE HRRR INDICATED BEHIND THIS FRONT BASED ON WIND SPEEDS CURRENTLY OCCURRING BEHIND THIS FRONT ACROSS EASTERN CO AND FAR SOUTHWEST NEBRASKA AND SURFACE PRESSURE TENDENCIES. WINDS WILL BEGIN TO SUBSIDE AFTER 03Z AS THE COLD FRONT QUICKLY MOVES INTO CENTRAL KANSAS AND NORTHWEST OKLAHOMA. WIND SPEEDS ARE EXPECTED TO FALL BACK INTO AROUND 10KTS AFTER MIDNIGHT. -RB && .PREV DISCUSSION... /ISSUED 301 PM CST THU DEC 29 2011/ DISCUSSION... DAYS 1-2... THE MAIN FORECAST CHALLENGES ARE TEMPERATURES ESPECIALLY IN SNOWPACK AREAS, AND WINDS AND TEMPS ON SATURDAY WITH A COLD FRONT. TWO STRONG UPPER LEVEL SHORTWAVE TROUGHS WILL PASS THROUGH THE PLAINS IN NORTHWESTERLY FLOW ALOFT THROUGH FRIDAY WITH ONLY SOME HIGH TO MID LEVEL CLOUDS AT TIMES. NO PRECIPITATION IS EXPECTED. THE FIRST WAVE TONIGHT WILL SWITCH WEST TO SOUTHWEST WINDS TO THE NORTHWEST AT 10 TO 20 MPH OVERNIGHT WITH LOWS FROM THE MID 20S NORTHWEST TO LOW TO MID 30S ELSEWHERE. EXPECT HIGHS ON FRIDAY IN THE 40S IN SNOWPACK AREAS AND MID TO UPPER 50S ELSEWHERE. THE 2ND WAVE WILL BE STRONGER AND A LITTLE MORE SOUTH AND WILL MOVE INTO THE CENTRAL PLAINS ON SATURDAY AFTERNOON WITH A STRONG COLD FRONT. HOWEVER ON SATURDAY MORNING A STRONG LOW LEVEL INVERSION WILL BE IN PLACE. THE COLD FRONT WILL THEN MOVE ACROSS WESTERN KANSAS IN THE AFTERNOON PUSHING THE WARM AIR JUST ABOVE THE GROUND TO THE SURFACE. THIS SHOULD INITIALLY CAUSE A DRAMATIC WARM UP AT THE GROUND FOR A FEW HOURS BEFORE THE COLD AIR ADVECTION CATCHES UP. HIGHS COULD REACH THE MID TO UPPER 50S NORTH TO MID 60S SOUTH. THEN TEMPERATURES COULD FALL IN THE MID TO LATE AFTERNOON WITH GOOD COLD AIR ADVECTION BEHIND THE COLD FRONT. STRONG WINDS OF 25 TO 35 MPH ARE ALSO ANTICIPATED WITH THE COLD FRONT AND WE COULD BE CLOSE OR ABOVE WIND ADVISORY CRITERIA. DAYS 3-7... MEDIUM RANGE MODELS INDICATE AN UPPER LEVEL TROUGH OF LOW PRESSURE TRACKING EAST-SOUTHEAST ACROSS THE CENTRAL PLAINS SATURDAY EVENING THEN MOVING ACROSS THE GREAT LAKES REGION SUNDAY. AN ATTENDANT COLD FRONT IS PROGGED TO PUSH SOUTHEAST ACROSS WESTERN KANSAS SOMETIME BY SATURDAY EVENING. HOWEVER, WHAT LITTLE PRECIP DOES FALL IS EXPECTED TO REMAIN JUST OFF TO OUR NORTH WITH THE STRENGTH OF THE UPPER LEVEL SYSTEM. A REAL LACK OF LOW LEVEL MOISTURE WILL ALSO HURT ANY PRECIP CHANCES IN WESTERN KANSAS. FAIRLY DRY CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE MIDDLE OF THE WEEK AS UPPER LEVEL RIDGING DEVELOPS ACROSS THE INTERMOUNTAIN WEST AND BEGINS TO EDGE EASTWARD. TEMPERATURES ARE EXPECTED TO BE MUCH COOLER SUNDAY IN WAKE OF THE COLD FRONTAL PASSAGE FORECAST TO PUSH THROUGH WESTERN KANSAS BY SATURDAY NIGHT. COLDER AIR...WITH H85 TEMPERATURES DOWN AROUND 3C BELOW TO 5C BELOW...WILL SPILL SOUTH INTO WESTERN KANSAS THROUGH THE DAY SUNDAY. LOOK FOR WIDESPREAD 40S(F) WITH UPPER 30S(F) POSSIBLE IN WEST CENTRAL KANSAS. THE COOLER TEMPERATURES. A SLIGHT AND GRADUAL WARMING TREND IS THEN EXPECTED TO TAKE PLACE EARLY NEXT WEEK AS UPPER LEVEL RIDGING DEVELOPS ACROSS THE INTERMOUNTAIN WEST AND BEGINS TO EDGE TOWARD THE WESTERN HIGH PLAINS. && .PRELIMINARY POINT TEMPS/POPS... DDC 29 54 31 59 / 0 0 0 0 GCK 25 45 30 58 / 0 0 0 0 EHA 29 50 32 60 / 0 0 0 0 LBL 27 51 31 61 / 0 0 0 0 HYS 30 47 30 57 / 0 0 0 0 P28 33 58 34 65 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1019 AM MST WED DEC 28 2011 .SYNOPSIS... 222 AM MST WED DEC 28 2011 LATEST SATELLITE IMAGERY AND RUC ANALYSIS SHOW AN UPPER LEVEL RIDGE OVER THE WEST COAST...WITH AREAS OF CLOUDS AND PRECIPITATION MOVING ALONG THE NORTHERN PERIPHERY. OVER THE HIGH PLAINS A SHORT WAVE TROUGH WAS PROGRESSING SOUTHEAST INTO TEXAS. AT THE SURFACE A TROUGH WAS MOVING THROUGH THE TRI-STATE AREA WITH SOUTHWEST WINDS TURNING TO THE NORTHWEST BEHIND THE TROUGH. JTL && .SHORT TERM (TODAY-FRIDAY)... 222 AM MST WED DEC 28 2011 ABOVE NORMAL TEMPERATURES WILL BE THE FOCUS FOR THIS PERIOD. TODAY...NORTHWEST FLOW WILL CONTINUE OVER THE AREA WITH A MINOR SHORT WAVE TROUGH MOVING THROUGH THE FLOW DURING THE DAY. WITH THE RIGHT EXIT REGION OF THE JET MOVING IN AND SOME MOISTURE MOVING THROUGH THE FLOW...AM NOT ANTICIPATING ANYTHING MORE THAN SOME CLOUDS. WINDS WILL BE BREEZY TODAY AS SOME OF THE STRONGER WINDS ABOVE THE SURFACE ACCOMPANYING THE TROUGH ARE ABLE TO MIX DOWN. TEMPERATURES WILL BE WARMER THAN YESTERDAY AS 850MB TEMPERATURES WARM BEHIND THE TROUGH. THURSDAY AND FRIDAY...A COUPLE OF SHORT WAVE TROUGHS WILL MOVE THROUGH THE NORTHWEST FLOW...PLACING THE RIGHT ENTRANCE AND LEFT EXIT REGIONS OF THE JET OVER THE TRI-STATE AREA. SOME 700-300MB FRONTOGENESIS WILL MOVE OVER THE AREA WITH THESE TROUGHS. MODELS DISAGREE WITH HOW MUCH MOISTURE IS PRESENT AS THE TROUGHS MOVE THROUGH...ESPECIALLY FOR THE TROUGH COMING THROUGH FRIDAY MORNING. SREF PRECIPITATION PROBABILITIES ARE ZERO WHILE THE GEFS DOES SHOW A SMALL CHANCE FOR SOME MINIMAL PRECIPITATION IN THE BENKELMAN...MCCOOK AND OBERLIN AREA. WITH SUCH DISAGREEMENT AMONG MODELS...WILL LEAVE FORECAST DRY FOR NOW. WINDS WILL STRENGTHEN THURSDAY AS STRONG UPPER LEVEL WINDS ACCOMPANY THE TROUGH THROUGH THE AREA AND ARE ABLE TO MIX TO THE SURFACE. CURRENTLY LOOKS LIKE AREAS NORTH OF HIGHWAY 36 WILL HAVE THE BEST MIXING AND STRONGEST WINDS...WITH GUSTS UP TO 35 MPH POSSIBLE. THE WINDS WILL DECREASE AT SUNSET. FRIDAY WINDS WILL BE LIGHT AS A SURFACE HIGH PRESSURE MOVES INTO THE AREA AHEAD OF A DEVELOPING SURFACE TROUGH OVER COLORADO. TEMPERATURE-WISE THURSDAY WILL BE THE WARMEST...WITH HIGHS REACHING THE LOWER 60S THANKS TO 850MB TEMPERATURES WARMING AS THE TROUGH MOVES THROUGH. FRIDAY TEMPERATURES WILL BE A FEW DEGREES COOLER AS COOLER AIR BEHIND THE TROUGH FROM FRIDAY MORNING MOVES INTO THE AREA. JTL .LONG TERM (SATURDAY-TUESDAY)... 222 AM MST WED DEC 28 2011 NEW ECMWF IS MORE IN LINE WITH THE GFS SATURDAY BRINGING A SHORTWAVE TROUGH AND COLD FRONT THROUGH THE FORECAST AREA. DEPENDING ON THE TIMING OF THE FRONT...TEMPERATURES MAY WARM NICELY IN THE MORNING. CURRENT PROJECTIONS OF FRONTAL PASSAGE IN THE AFTERNOON...THOUGH...WILL LIMIT TOO MUCH WARMING...AND WILL CONTINUE WITH HIGH TEMPERATURES IN THE LOWER TO MID 50S. ECMWF CONTINUES TO DEPICT LIGHT PRECIPITATION SATURDAY NIGHT OVER THE NORTHERN SECTION OF AREA...BUT AGREE WITH OTHER MODELS ABOUT THE LIMITED AMOUNT OF MOISTURE SO WILL CONTINUE WITH A DRY FORECAST. STRONG 500 MB RIDGE WILL THEN BUILD OVER THE WESTERN UNITED STATES BEGINNING SUNDAY AND CONTINUING THROUGH THE EARLY PART OF NEXT WEEK. THE QUESTION WILL BE HOW FAR EAST THE RIDGE AXIS MOVES AND HOW STRONG THE HEIGHT RISES WILL BE. THE ECMWF IS SLIGHTLY STRONGER WITH THE RIDGE AXIS...BUT ALSO FURTHER WEST OF THE GFS. THIS PLACES STRONG NORTH TRAJECTORIES OVER THE AREA MONDAY FOR SOME COLD AIR ADVECTION. THE GFS IS FURTHER EAST AND WOULD SUPPORT WARMER TEMPERATURES. REGARDLESS...BOTH MODELS PROG 500 MB HEIGHTS OVER 576 METERS BY TUESDAY FOR ABOVE NORMAL TEMPERATURES AND CONTINUED DRY. && .AVIATION... 1019 AM MST WED DEC 28 2011 FOR THE 18Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. WINDS WILL BE WESTERLY...AND SIMILAR TO YESTERDAY...KGLD WILL SEE AFTERNOON GUSTS NEARING 20 KNOTS. HIGH CLOUDS WILL MOVE OVER THE TERMINALS THROUGHOUT THE AFTERNOON. ANY REMAINING GUSTS WILL SUBSIDE NEAR 00Z AS DAYTIME MIXING ENDS. CJS && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
404 AM MST WED DEC 28 2011 .SYNOPSIS... 222 AM MST WED DEC 28 2011 LATEST SATELLITE IMAGERY AND RUC ANALYSIS SHOW AN UPPER LEVEL RIDGE OVER THE WEST COAST...WITH AREAS OF CLOUDS AND PRECIPITATION MOVING ALONG THE NORTHERN PERIPHERY. OVER THE HIGH PLAINS A SHORT WAVE TROUGH WAS PROGRESSING SOUTHEAST INTO TEXAS. AT THE SURFACE A TROUGH WAS MOVING THROUGH THE TRI-STATE AREA WITH SOUTHWEST WINDS TURNING TO THE NORTHWEST BEHIND THE TROUGH. JTL && .SHORT TERM (TODAY-FRIDAY)... 222 AM MST WED DEC 28 2011 ABOVE NORMAL TEMPERATURES WILL BE THE FOCUS FOR THIS PERIOD. TODAY...NORTHWEST FLOW WILL CONTINUE OVER THE AREA WITH A MINOR SHORT WAVE TROUGH MOVING THROUGH THE FLOW DURING THE DAY. WITH THE RIGHT EXIT REGION OF THE JET MOVING IN AND SOME MOISTURE MOVING THROUGH THE FLOW...AM NOT ANTICIPATING ANYTHING MORE THAN SOME CLOUDS. WINDS WILL BE BREEZY TODAY AS SOME OF THE STRONGER WINDS ABOVE THE SURFACE ACCOMPANYING THE TROUGH ARE ABLE TO MIX DOWN. TEMPERATURES WILL BE WARMER THAN YESTERDAY AS 850MB TEMPERATURES WARM BEHIND THE TROUGH. THURSDAY AND FRIDAY...A COUPLE OF SHORT WAVE TROUGHS WILL MOVE THROUGH THE NORTHWEST FLOW...PLACING THE RIGHT ENTRANCE AND LEFT EXIT REGIONS OF THE JET OVER THE TRI-STATE AREA. SOME 700-300MB FRONTOGENESIS WILL MOVE OVER THE AREA WITH THESE TROUGHS. MODELS DISAGREE WITH HOW MUCH MOISTURE IS PRESENT AS THE TROUGHS MOVE THROUGH...ESPECIALLY FOR THE TROUGH COMING THROUGH FRIDAY MORNING. SREF PRECIPITATION PROBABILITIES ARE ZERO WHILE THE GEFS DOES SHOW A SMALL CHANCE FOR SOME MINIMAL PRECIPITATION IN THE BENKELMAN...MCCOOK AND OBERLIN AREA. WITH SUCH DISAGREEMENT AMONG MODELS...WILL LEAVE FORECAST DRY FOR NOW. WINDS WILL STRENGTHEN THURSDAY AS STRONG UPPER LEVEL WINDS ACCOMPANY THE TROUGH THROUGH THE AREA AND ARE ABLE TO MIX TO THE SURFACE. CURRENTLY LOOKS LIKE AREAS NORTH OF HIGHWAY 36 WILL HAVE THE BEST MIXING AND STRONGEST WINDS...WITH GUSTS UP TO 35 MPH POSSIBLE. THE WINDS WILL DECREASE AT SUNSET. FRIDAY WINDS WILL BE LIGHT AS A SURFACE HIGH PRESSURE MOVES INTO THE AREA AHEAD OF A DEVELOPING SURFACE TROUGH OVER COLORADO. TEMPERATURE-WISE THURSDAY WILL BE THE WARMEST...WITH HIGHS REACHING THE LOWER 60S THANKS TO 850MB TEMPERATURES WARMING AS THE TROUGH MOVES THROUGH. FRIDAY TEMPERATURES WILL BE A FEW DEGREES COOLER AS COOLER AIR BEHIND THE TROUGH FROM FRIDAY MORNING MOVES INTO THE AREA. JTL .LONG TERM (SATURDAY-TUESDAY)... 222 AM MST WED DEC 28 2011 NEW ECMWF IS MORE IN LINE WITH THE GFS SATURDAY BRINGING A SHORTWAVE TROUGH AND COLD FRONT THROUGH THE FORECAST AREA. DEPENDING ON THE TIMING OF THE FRONT...TEMPERATURES MAY WARM NICELY IN THE MORNING. CURRENT PROJECTIONS OF FRONTAL PASSAGE IN THE AFTERNOON...THOUGH...WILL LIMIT TOO MUCH WARMING...AND WILL CONTINUE WITH HIGH TEMPERATURES IN THE LOWER TO MID 50S. ECMWF CONTINUES TO DEPICT LIGHT PRECIPITATION SATURDAY NIGHT OVER THE NORTHERN SECTION OF AREA...BUT AGREE WITH OTHER MODELS ABOUT THE LIMITED AMOUNT OF MOISTURE SO WILL CONTINUE WITH A DRY FORECAST. STRONG 500 MB RIDGE WILL THEN BUILD OVER THE WESTERN UNITED STATES BEGINNING SUNDAY AND CONTINUING THROUGH THE EARLY PART OF NEXT WEEK. THE QUESTION WILL BE HOW FAR EAST THE RIDGE AXIS MOVES AND HOW STRONG THE HEIGHT RISES WILL BE. THE ECMWF IS SLIGHTLY STRONGER WITH THE RIDGE AXIS...BUT ALSO FURTHER WEST OF THE GFS. THIS PLACES STRONG NORTH TRAJECTORIES OVER THE AREA MONDAY FOR SOME COLD AIR ADVECTION. THE GFS IS FURTHER EAST AND WOULD SUPPORT WARMER TEMPERATURES. REGARDLESS...BOTH MODELS PROG 500 MB HEIGHTS OVER 576 METERS BY TUESDAY FOR ABOVE NORMAL TEMPERATURES AND CONTINUED DRY. && .AVIATION... 404 AM MST WED DEC 28 2011 FOR THE 12Z TAFS...VFR CONDITIONS WILL CONTINUE AT KGLD/KMCK THE NEXT 24 HOURS. SURFACE WINDS WILL GENERALLY BE 5-15 KNOTS...THOUGH A FEW HIGHER GUSTS MAY OCCUR AT KGLD FROM 19Z-23Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
238 AM MST WED DEC 28 2011 .SYNOPSIS... 222 AM MST WED DEC 28 2011 LATEST SATELLITE IMAGERY AND RUC ANALYSIS SHOW AN UPPER LEVEL RIDGE OVER THE WEST COAST...WITH AREAS OF CLOUDS AND PRECIPITATION MOVING ALONG THE NORTHERN PERIPHERY. OVER THE HIGH PLAINS A SHORT WAVE TROUGH WAS PROGRESSING SOUTHEAST INTO TEXAS. AT THE SURFACE A TROUGH WAS MOVING THROUGH THE TRI-STATE AREA WITH SOUTHWEST WINDS TURNING TO THE NORTHWEST BEHIND THE TROUGH. JTL && .SHORT TERM (TODAY-FRIDAY)... 222 AM MST WED DEC 28 2011 ABOVE NORMAL TEMPERATURES WILL BE THE FOCUS FOR THIS PERIOD. TODAY...NORTHWEST FLOW WILL CONTINUE OVER THE AREA WITH A MINOR SHORT WAVE TROUGH MOVING THROUGH THE FLOW DURING THE DAY. WITH THE RIGHT EXIT REGION OF THE JET MOVING IN AND SOME MOISTURE MOVING THROUGH THE FLOW...AM NOT ANTICIPATING ANYTHING MORE THAN SOME CLOUDS. WINDS WILL BE BREEZY TODAY AS SOME OF THE STRONGER WINDS ABOVE THE SURFACE ACCOMPANYING THE TROUGH ARE ABLE TO MIX DOWN. TEMPERATURES WILL BE WARMER THAN YESTERDAY AS 850MB TEMPERATURES WARM BEHIND THE TROUGH. THURSDAY AND FRIDAY...A COUPLE OF SHORT WAVE TROUGHS WILL MOVE THROUGH THE NORTHWEST FLOW...PLACING THE RIGHT ENTRANCE AND LEFT EXIT REGIONS OF THE JET OVER THE TRI-STATE AREA. SOME 700-300MB FRONTOGENESIS WILL MOVE OVER THE AREA WITH THESE TROUGHS. MODELS DISAGREE WITH HOW MUCH MOISTURE IS PRESENT AS THE TROUGHS MOVE THROUGH...ESPECIALLY FOR THE TROUGH COMING THROUGH FRIDAY MORNING. SREF PRECIPITATION PROBABILITIES ARE ZERO WHILE THE GEFS DOES SHOW A SMALL CHANCE FOR SOME MINIMAL PRECIPITATION IN THE BENKLEMEN...MCCOOK AND OBERLIN AREA. WITH SUCH DISAGREEMENT AMONG MODELS...WILL LEAVE FORECAST DRY FOR NOW. WINDS WILL STRENGTHEN THURSDAY AS STRONG UPPER LEVEL WINDS ACCOMPANY THE TROUGH THROUGH THE AREA AND ARE ABLE TO MIX TO THE SURFACE. CURRENTLY LOOKS LIKE AREAS NORTH OF HIGHWAY 36 WILL HAVE THE BEST MIXING AND STRONGEST WINDS...WITH GUSTS UP TO 35 MPH POSSIBLE. THE WINDS WILL DECREASE AT SUNSET. FRIDAY WINDS WILL BE LIGHT AS A SURFACE HIGH PRESSURE MOVES INTO THE AREA AHEAD OF A DEVELOPING SURFACE TROUGH OVER COLORADO. TEMPERATURE-WISE THURSDAY WILL BE THE WARMEST...WITH HIGHS REACHING THE LOWER 60S THANKS TO 850MB TEMPERATURES WARMING AS THE TROUGH MOVES THROUGH. FRIDAY TEMPERATURES WILL BE A FEW DEGREES COOLER AS COOLER AIR BEHIND THE TROUGH FROM FRIDAY MORNING MOVES INTO THE AREA. JTL .LONG TERM (SATURDAY-TUESDAY)... 222 AM MST WED DEC 28 2011 NEW ECMWF IS MORE IN LINE WITH THE GFS SATURDAY BRINGING A SHORTWAVE TROUGH AND COLD FRONT THROUGH THE FORECAST AREA. DEPENDING ON THE TIMING OF THE FRONT...TEMPERATURES MAY WARM NICELY IN THE MORNING. CURRENT PROJECTIONS OF FRONTAL PASSAGE IN THE AFTERNOON...THOUGH...WILL LIMIT TOO MUCH WARMING...AND WILL CONTINUE WITH HIGH TEMPERATURES IN THE LOWER TO MID 50S. ECMWF CONTINUES TO DEPICT LIGHT PRECIPITATION SATURDAY NIGHT OVER THE NORTHERN SECTION OF AREA...BUT AGREE WITH OTHER MODELS ABOUT THE LIMITED AMOUNT OF MOISTURE SO WILL CONTINUE WITH A DRY FORECAST. STRONG 500 MB RIDGE WILL THEN BUILD OVER THE WESTERN UNITED STATES BEGINNING SUNDAY AND CONTINUING THROUGH THE EARLY PART OF NEXT WEEK. THE QUESTION WILL BE HOW FAR EAST THE RIDGE AXIS MOVES AND HOW STRONG THE HEIGHT RISES WILL BE. THE ECMWF IS SLIGHTLY STRONGER WITH THE RIDGE AXIS...BUT ALSO FURTHER WEST OF THE GFS. THIS PLACES STRONG NORTH TRAJECTORIES OVER THE AREA MONDAY FOR SOME COLD AIR ADVECTION. THE GFS IS FURTHER EAST AND WOULD SUPPORT WARMER TEMPERATURES. REGARDLESS...BOTH MODELS PROG 500 MB HEIGHTS OVER 576 METERS BY TUESDAY FOR ABOVE NORMAL TEMPERATURES AND CONTINUED DRY. && .AVIATION... 942 PM MST TUE DEC 27 2011 VFR CONDS WILL PREVAIL AT BOTH TERMINALS THROUGH THE NEXT 24 HOURS. NORTHWESTERLY WINDS TO BEGIN THE PERIOD WILL SLOWLY SWITCH TO THE WEST AND SOUTHWEST BY WEDNESDAY AFTERNOON. MID/HIGH CLOUDS WILL BE ABUNDANT AS UPPER LEVEL DISTURBANCES MOVE OVER THE REGION. BAS && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1211 AM EST WED DEC 28 2011 ...Updated Aviation Discussion... .Forecast Update... Snowfall earlier today occurred across all of the South Indiana counties, with most counties in north central Kentucky also seeing traces. The only accumulations noted in our forecast area were in Dubois, Orange, Crawford, and Washington counties, where at most a half inch accumulated on grassy and elevated surfaces. That snow now has melted. The expected follow-up precipitation has taken a little longer than expected to develop, much later than the HRRR indicated but in line with the 12Z SPC WRF. The latter model pointed more to the upslope causing snows over the eastern forecast area, and latest 88D is now showing some indication that a drizzle/flurry mix is developing in this region. Based on dry air driving its way into the region, this precipitation will not last more than a few more hours. Likely will continue to issue the special weather statement about some slick spots on area roads overnight. Winds this afternoon and evening have done a good job of drying out area roadways according to road webcams. Still expect a few patches to have been wind protected, and with temperatures falling into the upper 20s, these patches should freeze over. && .Short Term (This Evening - Wednesday)... Precipitation has all but ended across the CWA with barely measurable rain or light snow moving east of I 65 and into the Bluegrass. Several calls were made to southern Indiana and west central Kentucky counties late this morning/early this afternoon with most locations only picking up traces of snowfall. The most noticeable accumulations were in Dubois county where up to a half inch accumulated on grassy surfaces and cars. Also of note, the all time precipitation record for a year was broken at Lexington today. As of 7 AM EST this morning, total rainfall for the year at Lexington was 65.86 inches which surpassed the old record of 65.76 inches set back in 1935. Additional rainfall amounts of around a half an inch fell after 7 AM and will be tallied after precipitation ends later this evening. Surface low has moved off to the northeast and is on its way to the eastern Great Lakes this evening. Surface winds will continue to be strong as pressure gradient is tight behind the deepening low. Look for west northwest winds between 10 and 20 mph, gusting as high as 30 mph through about 7 PM EST. Thereafter, winds will gradually slacken to the 5 to 15 mph range overnight. Looking upstream across west central Indiana and southern Illinois, temperatures have warmed back into the upper 30s and lower 40s. Raw Nam surface temperatures had this depicted well so have used them for the temperature trend through this evening. Temperatures will remain steady or warm slightly to the upper 30s before gradually falling after midnight to the upper 20s and around 30 degrees. Will have to watch a secondary surge of low level moisture streaming into the area from the northwest as this could produce flurries or a light snow shower with west northwest flow aiding in some upslope lift. Also, a look at forecast soundings actually shows some convective instability in the lowest levels, although saturation only makes it to about -8 C before low level moisture is cut off. Given the fact that ice crystals may be hard to come by and low level moisture is shallow, will only include flurries along and west of I 65 late this afternoon and this evening. Best chance for a light snow shower will be in the Bluegrass. Will let SPS that had voiced concern about scattered moderate snow showers and re-freezing of roadways overnight expire at 5 PM EST. Otherwise, precipitation threat exits the Bluegrass region shortly after midnight with dry weather and mostly clear to partly cloudy skies through Wednesday. The west northwest wind will continue on Wednesday and only allow highs to get into the upper 30s to around 40 degrees. .Long Term (Wednesday Night - Tuesday)... The first weather system of interest in the long term period is a clipper system diving down from the NW for Thurs night/Fri. This system should bring light rain to portions of southern Indiana and north central KY including the Bluegrass. Ahead of this system, temperatures will warm into the upper 40s and lower 50s for highs on Thurs. Lows should range from the upper 20s/lower 30s Wed night to upper 30s/lower 40s for Thurs night. We`ll see a brief break in weather systems Friday Night/Saturday before the pattern reloads. There is very low confidence in the weekend weather system. The 12Z ECMWF overly deepens a significant trough over the Plains states by early next week while the 12Z GFS depicts a much shallower progressive trough. Think that the real soln is some where in the middle so tried to reflect that in the grids. Will keep low 20-30% POPs Sat night-Sun night until a reasonable consensus can be reached. Seems like the 12Z GFS trended deeper with its trough, however, the 12Z ECMWF looks like it fell off the deep end with digging such a deep trough over the CONUS. The degree of troughing will determine temperatures and weather type. Right now will put highs in the 50s ahead of it and 30s and 40s behind it. && .Aviation (06Z TAF Issuance)... Back edge of clouds associated with an exiting upper trough/lake effect enhancement will soon move across the terminals and SDF and LEX will improve to VFR (BWG will remain VFR). Through the next few hours though, roughly by 09z, CIGs at SDF/LEX will be in the MVFR range with even a small chance for very light snow/drizzle mix at LEX. Gusty winds may occur, as well, over the next few hours. By or shortly after 12z, high pressure will spread across the region, helping to relax our gusty northwest winds as they back around to the west-southwest. A weak upper level wave will bring in mid-upper level clouds nearly as soon as the strato-cu deck exits this morning. However, VFR conditions will be the rule from mid-morning on. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........RJS Short Term.......BJS Long Term........AMS Aviation.........AL
AREA FORECAST DISCUSSION
NWS GRAY ME
1141 PM EST TUE DEC 27 2011 .SYNOPSIS... LOW PRESSURE WILL MOVE NORTHEAST THROUGH EASTERN NEW YORK AND INTO SOUTHERN QUEBEC OVERNIGHT. A STRONG NORTHWEST FLOW WILL SET UP BEHIND THE DEPARTING LOW ON WEDNESDAY. WEAK HIGH PRESSURE WILL BUILD IN FROM THE WEST ON THURSDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST THURSDAY NIGHT AND STALL OVER THE REGION ON FRIDAY AS SEVERAL WEAK AREAS OF LOW PRESSURE MOVE EAST ALONG IT. THE LAST AREA OF LOW PRESSURE WILL CROSS SOUTHERN NEW ENGLAND ON SATURDAY. A WEAK AREA OF HIGH PRESSURE WILL BUILD OVER THE AREA SATURDAY NIGHT AND WILL SHIFT OFFSHORE ON SUNDAY AS A WARM FRONT MOVES IN FROM THE SOUTHWEST. LOW PRESSURE WILL MOVE EAST THROUGH NORTHERN NEW ENGLAND SUNDAY NIGHT AND INTO THE MARITIMES ON MONDAY. && .NEAR TERM /THROUGH WEDNESDAY/... UPDATE...MID LEVEL WARM AIR HAS NOW PUSHED TO THE CANADIAN BORDER... AND THE SURFACE WARM FRONT HAS PUSHED INLAND ACROSS NORTHERN NEW ENGLAND. STILL SOME AREAS IN THE FOOTHILLS THAT HAVE NOT SEEN THE SWITCH TO SOUTHEAST WINDS AND DRAMATICALLY WARMING TEMPERATURES YET. FRYEBURG... PLYMOUTH... AND LEBANON ARE STILL IN THE MID 30S WITH A LIGHT NORTH WIND. NORTH OF THE MOUNTAINS... THE SOUTHEAST WINDS ALOFT HAVE A DOWNSLOPING COMPONENT TO PUSH THE COLD SURFACE AIR OUT SOONER... HELPING WHITEFIELD AND BERLIN CLIMB INTO THE 40S WITH A GUSTY SOUTHEAST WIND. EXPECT RAIN FROM HERE ON OUT. DRY SLOT ALOFT IS PUSHING ACROSS THE AREA... LEADING TO A MORE SHOWERY CONVECTIVE NATURE TO THE RAIN. SURFACE TROUGH AXIS IS MOVING INTO VERMONT AND MASSACHUSETTS... BRINGING AN END TO THE PRECIPITATION AS IT MOVES THROUGH. HAVE UPDATED THE POPS AND TEMPERATURE GRIDS TO REFLECT CURRENT THINKING REGARDING TIMING OF PRECIPITATION AND WARM AIR. UPDATE... TEMPERATURES ARE NOW TAKING OFF AND HAVE ADJUSTED THE GRIDS TO REFLECT A NON-DIURNAL CURVE WITH THE MIN TEMPERATURE FIELD. THIS RAPID WARMING IN THE COLUMN THIS EVENING HAS ALLOWED THE MIXED PCPN TO SWITCH OVER TO MAINLY RAIN. THEREFORE...HAVE ALLOWED THE FREEZING RAIN ADVISORIES TO EXPIRE. HAVE MENTIONED THIS CHANGEOVER IN THE HWO AND CONTINUED THE POSSIBILITY OF "PATCHY" FREEZING RAIN IN THE COLDEST OF THE VALLEYS IN THE MOUNTAINS/FOOTHILLS THROUGH MIDNIGHT. THE RAPID WARMING HAS ALSO ALLOWED FOR INCREASED MIXING AND HIGHER WIND GUSTS THIS LAST HOUR. CONVECTIVE LOOKING RADAR IMAGERY TO OUR SOUTH WILL QUICKLY MOVE NORTHWARD...BRINGING THE WIND GUSTS UP SIGNIFICANTLY ALONG THE COAST AND THE HIGHER TERRAIN OVER THE NEXT ONE TO TWO HOURS. HAVE ALLOWED FOR THE ENDING OF THE WIND ADVISORIES AROUND 10Z. AT THAT TIME...THE HRRR EXITS THE BEST PRESSURE GRADIENT OUT OF OUR FORECAST AREA AND EAST OF PENOBSCOT BAY. THE REST OF THE GRIDS WILL REMAIN RELATIVELY UNCHANGED. HAVE NUDGED THE WAVE FORECAST UPWARDS BASED ON THE SWAN GFS WHICH...DYNAMICALLY MAKES MORE SENSE AND ALSO ALLOWS US TO BE MORE CONSISTENT WITH OUR CURRENT POSTED MWW. PREV DISC... SOME ADJUSTMENTS MADE TO THE GRIDS BASED ON CURRENTS CONDITIONS. HAVE USED A NON-DIURNAL TEMPERATURE CURVE FOR OVERNIGHT LOWS. ALSO...HAVE UPPED THE POPS FOR THE FIRST HALF OF THE NIGHT AS PCPN SHIELD CONTINUES TO QUICKLY MOVE NORTH AND EAST ACROSS THE FORECAST AREA...DESPITE INITIAL DRY CONDITIONS PER VERY DRY 12Z GYX SOUNDING. THIS IS ALSO IN GOOD AGREEMENT WITH THE LATEST HRRR UPDATE THIS HOUR. THERE MAY CONTINUE TO BE AREAS OF -FZRA EARLY TONIGHT AS BOUNDARY LAYER TEMPS CONTINUE TO HOVER AROUND FREEZING IN THE NORTHERN SHELTERED VALLEYS. HAVE ISSUED A FREEZING RAIN ADVISORY UNTIL 10 PM FOR THIS REGION. HAVE ALSO ADDED A CHANCE FOR FREEZING RAIN IN CENTRAL NH AND THE FOOTHILLS OF MAINE THROUGH THIS EVENING BASED ON CURRENT AND SHORT TERM FORECAST CONDITIONS. REST OF GRIDS WILL REMAIN UNCHANGED...HOWEVER...MAY NEED TO TWEAK WIND GUST GRIDS TO BETTER MATCH CURRENT PRODUCTS. && .SHORT TERM /WEDNESDAY NIGHT/... COLDER AIR WILL MOVE BACK INTO THE REGION ON WEDNESDAY AS LOW PRESSURE CONTINUES TO MOVE OFF TO THE NORTHEAST. EXPECT ANY SHOWERS DOWNWIND OF THE MOUNTAINS TO END DURING THE MORNING HOURS. IN THE NORTH WILL SEE RAIN SHOWERS CHANGING TO SNOW SHOWERS IN THE MOUNTAINS WITH SOME MINOR ACCUMULATIONS POSSIBLE. EXPECT STEADY OR SLOWLY FALLING TEMPERATURES DURING THE DAY WITH MOST AREAS DIPPING TO THE FREEZING MARK BY LATE AFTERNOON. EXPECT NORTHWEST WINDS TO INCREASE SIGNIFICANTLY DURING THE AFTERNOON...POSSIBLY REACHING ADVISORY LEVELS. WINDY AND VERY COLD WEDNESDAY NIGHT WITH A CONTINUING CHANCE OF SNOW SHOWERS IN THE MOUNTAINS. ELSEWHERE SKIES WILL GRADUALLY CLEAR. EXPECT LOWS OF ZERO TO 5 BELOW IN THE NORTH AND IN THE LOWER TO MID TEENS IN THE SOUTH. && .LONG TERM /THURSDAY THROUGH TUESDAY/... UPR LVL CUTOFF OVER THE MARITIMES WITH ASSOCIATED DEEP SFC CYCLONE WILL SLOWLY LIFT NE ON THURSDAY ALLOWING A MORE UPR LVL ZONAL FLOW TO SET UP WITH AN EMBEDDED VORTICITY MAX/JET SEGMENT TO MOVE TOWARD THE NE. THIS BRINGS A WEAK SFC LOW AND LEADING WRM FNT TOWARD NEW ENGLAND. THESE FEATURES CROSS NEW ENGLAND THURSDAY NGT CREATING CLOUDS AND SOME -SN. ON FRIDAY A SECOND UPR LVL VORTICITY MAX/JET SEGMENT IN THE WESTERLY FLOW ALOFT MOVES THRU WITH ANOTHER WEAK SFC LOW AND ROUND OF SOME -SN. THIS IS FOLLOWED BY A STRONG UPR LVL SHORT WAVE/VORTICITY MAX ON SATURDAY. THIS FORMS A SFC LOW ALONG THE MID ATLANTIC COAST THAT STRENGTHENS AS IT MOVES EAST INTO THE ATLANTIC. THE CURRENT TRACK IS TOO FAR S TO PROVIDE MUCH IN THE WAY OF PRCP FOR THE FCST AREA... BUT SOME -SN CAN`T BE RULED OUT...ESPECIALLY IF IT ENDS UP TRACKING A BIT FURTHER N. AN UPR LVL RIDGE FOLLOWS THE TROF WITH A SFC RIDGE OF HIGH PRES CROSSING THE REGION SATURDAY NGT PROVIDING FAIR WX. YET ANOTHER UPR LVL SHORT WAVE MOVES E INTO THE REGION ON SUNDAY. CURRENT MODEL FORECASTS SHOW THIS AS A STRONG UPR LVL SYSTEM WHICH BRINGS A SFC LOW E FROM THE UPR GREAT LAKES TOWARD NRN NEW ENGLAND SUNDAY THEN CROSSES NRN NEW ENGLAND SUNDAY NGT. THE TRACK OF THIS LOW MAY BRING IN ENOUGH WARM AIR SO THAT PRCP IS NOT CONFINED TO SN...THERE COULD BE RA OR EVEN MIXED SN/ICE/RA WITH THIS EVENT...WITH RA MORE LIKELY ALONG THE COAST AND THE N/MT ZONES MORE LIKELY TO SEE SN. LOTS OF TIME UNTIL THIS EVENT FOR THE TRACK AND/OR INTENSITY OF THIS SYSTEM TO CHANGE. THE LOW INTENSIFIES OVER THE MARITIMES ON MONDAY BRINGING IN MUCH COLDER CANADIAN AIR ON INCREASING AND VERY GUSTY NW WINDS. -SHSN PSBL ON MONDAY...ESPECIALLY ACROSS THE N/MT ZONES DUE TO OROGRAPHIC LIFTING UNDER THE UPR LVL CYCLONIC FLOW. THE COLD BLUSTER WX CONTINUES MONDAY NGT AND TUESDAY. GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR THURSDAY AND THURSDAY NGT. USED GMOS FOR REST OF THE LONG TERM FCST...EXCEPT USED A BLEND OF GFS AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM...MVFR/IFR CEILINGS DEVELOPING THIS EVENING...IMPROVING TO VFR WEDNESDAY MORNING. VFR WEDNESDAY NIGHT WITH AREAS OF MVFR CEILINGS AND VSBY IN SNOW SHOWERS IN THE NORTH. LONG TERM /THURSDAY THROUGH SUNDAY/...MVFR TO MAYBE IFR CONDITIONS PSBL THURSDAY NGT THRU FRIDAY AS A SERIES OF WEAK SYSTEMS BRING THE POTENTIAL FOR SOME LGT SN. A STRONGER SYSTEM BRINGS THE CHC FOR SN AND IFR CONDITIONS ON SATURDAY FOLLOWED BY ANOTHER STRENGTHENING LOW PRES SYSTEM BRINGING A CHC OF MIXED PRCP AND IFR CONDITIONS ON SUNDAY. && .MARINE... SHORT TERM...GALE WARNING THROUGH TONIGHT. RAISED SEAS RELYING HEAVILY ON THE SWAN GFS MODEL. LONG TERM /THURSDAY THROUGH SUNDAY/...CD NW FLOW ON THURSDAY MAY RESULT IN CONTINUED GALE FORCE WINDS... AT LEAST THRU THE MORNING. THE PRES GRADIENT LETS UP LATER IN THE DAY AS WINDS AND SEAS SUBSIDE. A SERIES OF WEAK LOW PRES SYSTEMS MOVE THRU THURSDAY NGT AND FRIDAY BUT CONDITIONS LIKELY TO STAY BELOW SCA LEVELS. LOW PRES PASSES WELL TO THE S ON SATURDAY SO AGAIN CONDITIONS LIKELY TO REMAIN BELOW SCA THRESHOLDS. A STRONGER LOW PRES SYSTEM MOVES IN FOR SUNDAY WHICH MAY PRODUCE SCA WINDS AND SEAS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WIND ADVISORY UNTIL 5 AM EST WEDNESDAY FOR MEZ023>028. NH...WIND ADVISORY UNTIL 5 AM EST WEDNESDAY FOR NHZ014. MARINE...GALE WARNING UNTIL 5 AM EST WEDNESDAY FOR ANZ150>154. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1246 PM EST WED DEC 28 2011 UPDATED AVIATION DISCUSSION FOR 18Z TAFS .UPDATE... LES CONTINUES ACROSS MARQUETTE AND ALGER COUNTIES AS THE FLOW REMAINS NORTHERLY OFF THE LAKE. WITH THE RIDGE AXIS OVERHEAD...THE FLOW SHOULD SHIFT TO THE SOUTH THIS AFTERNOON CAUSING THE LES TO END RATHER QUICKLY. SOME LIGHT SNOW/FLURRIES OVER MN ASSOCIATED WITH LEADING WARM ADVECTION WILL MOVE INTO WESTERN UPPER MI LATER THIS AFTERNOON BUT SHOULD BE OF LITTLE CONSEQUENCE. NO MAJOR CHANGES TO THE AFTERNOON FORECAST. BASED ON THE LATEST MODEL GUIDANCE...DID MAKE SOME SUBSTANTIAL CHANGES TO THE OVERNIGHT AND THURSDAY FORECAST FOR THE EASTERN PART OF THE FORECAST AREA. LOW PRESSURE OVER THE WESTERN DAKOTAS WILL MOVE TO THE WESTERN GREAT LAKES LATER TONIGHT INTO THURSDAY. THIS WILL PUT UPPER MICHIGAN IN A BROAD AREA OF ISENTROPIC LIFT/WARM ADVECTION. WITH THE BOUNDARY LAYER FLOW BEING SOUTH-SOUTHEAST LATE TONIGHT INTO THURSDAY COMBINED WITH 850MB TEMPS INITIALLY AROUND -11C (RISING TO -5C BY THU AFTN)...LAKE ENHANCED SNOW OFF OF LAKE MICHIGAN SEEMS MORE AND MORE LIKELY FOR SCHOOLCRAFT AND SOUTHERN LUCE COUNTIES. IN FACT...THE HIGHER RESOLUTION MODEL OUTPUT SUCH AS THE 4KM NAM NEST INDICATE UP TO 0.7 INCH OF LIQUID LATER TONIGHT INTO THURSDAY GENERALLY SOUTH OF M-28 IN SCHOOLCRAFT AND LUCE COUNTIES. STILL NEED TO TAKE A CLOSER LOOK AT THE 12Z RUNS...BUT GIVEN THAT THIS IS A GOOD SETUP FOR MODERATE TO HEAVY SNOW TO FALL OFF OF LAKE MICHIGAN IN SCHOOLCRAFT COUNTY...HAVE OPTED TO RAISE SNOW AMOUNTS TO A STORM TOTAL OF 3-6 INCHES AND RAISE POPS TO CATEGORICAL FOR THE SAME AREAS. MAY NEED TO ISSUE SOME HEADLINE TO ADDRESS THE SNOWFALL FOR THE EASTERN FORECAST AREA...HOWEVER IT IS STILL UNCLEAR IF A WARNING OR ADVISORY WILL BE NEEDED. THIS DECISION WILL LIKELY BE MADE LATER THIS AFTERNOON. OTHERWISE...THE REMAINDER OF THE AREA WILL SEE A GENERAL 1-3 INCH SNOWFALL WITH 700MB MIXING RATIO OF 2 G/KM OVERNIGHT INTO THU MORNING. && .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NE CANADA INTO ERN GREAT LAKES AND A FLAT RIDGE OVER THE WEST RESULTING IN NW FLOW FROM THE CANADIAN PRAIRIE THROUGH THE WRN GREAT LAKES. A SHEARED UPSTREAM SHORTWAVE TROUGH WAS MOVING INTO MANITOBA WHILE ANOTHER IN THE FAST WRLY FLOW OFF THE NE PACIFIC WAS LOCATED OVER SRN BC. AT THE SFC...A RIDGE EXTENDED FROM NRN ONTARIO INTO WRN WI LEAVING NRLY FLOW ACROSS LAKE SUPERIOR. 850 MB TEMPS AROUND -15C PROVIDED PLENTY OF INSTABILITY FOR LINGERING LES EVEN THROUGH VERY DRY AIR UPSTREAM AND INVERSION HEIGHTS DOWN TO AROUND 3K-4K FT. && .DISCUSSION... TODAY...EXPECT THAT THE LES WILL DIMINISH THIS MORNING AND END BY THIS AFTERNOON AS THE RIDGE MOVES ACROSS UPPER MICHIGAN AND WINDS BECOME OFFSHORE. ANY ACCUMULATIONS WITH SCT -SHSN INTO THE N CNTRL CWA THIS MORNING SHOULD AMOUNT TO LESS THAN AN INCH. RETURN SRLY FLOW WILL ALLOW MAX TEMPS TO REBOUND INTO THE UPPER TEENS AND LOWER 20S. TONIGHT INTO THU...MODELS SUGGEST THAT THE THE MID TO UPPER LEVEL FORCING WITH THE COMBINATION OF THE MANITOBA AND BC SHORTWAVES PASSING TO THE NORTH AND SOUTH OF UPPER MI WILL BE RELATIVELY MODEST. HOWEVER...AN AREA OF 285K-290K ISENTROPIC LIFT NORTH OF THE 850 MB LOW WILL SUPPORT WIDESPREAD LIGHT SNOW...MAINLY BTWN 06Z-18Z. WITH 2G-3G/KG AVBL...CONSENSUS QPF VALUES IN THE 0.1 TO 0.2...AND SNOW WATER RATIO VALUES NEAR 15/1...PREVIOUS FCST OF 1 TO 3 INCHES LOOKS ON TRACK. THERE IS GREATER UNCERTAINTY WITH THE POTENTIAL FOR HIGHER LAKE ENHANCED SNOW AMOUNTS WITH SRLY FLOW OFF OF LAKE MICHIGAN. THE HPC AND LCLY RUN HIGH RES WRF/ARW AS WELL AS THE CANADIAN REGIONAL GEM SUGGEST THAT A BAND MAY DEVELOP INTO WRN MACKINAC COUNTY LATE TONIGHT INTO EARLY THU AIDED BY LEVEL LEVEL CONV NEAR THE NW LOWER MI SHORE. THE BAND MAY SHIFT FARTHER WEST INTO SRN LUCE AND SRN SCHOOLCRAFT COUNTIES AS WINDS BACK IN RESPONSE TO THE WEAK SFC LOW MOVING TOWARD NRN LAKE MICHIGAN. ADDITIONAL SNOWFALL AMOUNTS OF SEVERAL INCHES COULD PUSH OVERALL AMOUNTS INTO THE ADVY CATEGORY IF THE BANDS DEVELOP AND PERSIST LONG ENOUGH AT ANY LOCATION. HOWEVER...CONFIDENCE IS BELOW AVERAGE WITH THESE DETAILS. THU NIGHT INTO FRI...LEFT OVER LIGHT SNOW OVER THE ERN PORTION OF THE CWA WILL GRADUALLY SLIDE OFF TO THE EAST AS WEAKER ISENTROPIC LIFT AND FGEN EXIT THE AREA. THE PATH OF THE NEXT SHORTWAVE REMAINS FAR ENOUGH SOUTH...PER GFS/ECMWF SO THAT FRI WILL REMAIN MAINLY DRY. SO...ONLY SLIGHT CHANCE POPS WERE INCLUDED. SAT THROUGH TUE...A PROGRESSIVE MID LEVEL TROUGH MOVES INTO THE PLAINS BRINGING WAA SAT. WITH LITTLE MOISTURE AVBL...LITTLE/NO MEASURABLE PCPN IS EXPECTED. THE GFS HAS TRENDED TOWARD THE GEM/ECMWF WITH TRANSITION TOWARD A MORE AMPLIFIED/MERIDIONAL PATTERN BY LATE SUN INTO MON. AN INFLUX OF COLD AIR (850 MB TEMPS DOWN INTO THE -17C TO -20C RANGE) BEHIND A COLD FRONT LATE SUN WITH DEEP MOISTURE AVAILABLE SHOULD BRING LES TO LOCATIONS FAVORED BY NW TO N FLOW TIL RIDING MOVES BACK IN BY TUE. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... EXPECT ANY REMAINING MVFR CIGS TO DISSIPATE EARLY THIS AFTN AT CMX AND SAW AS FLOW TURNS SOUTHERLY AND THE LES CLOUDS MOVE OFFSHORE. THE NEXT SYSTEM OVER THE PLAINS WILL APPROACH THE AREA TONIGHT. SOME LIGHT SNOW MAY SPREAD INTO IWD THIS AFTERNOON AS A WEAK WARM FRONT APPROACHES THE AREA. WIDESPREAD IFR CIGS AND VSBYS WILL SPREAD ACROSS THE AREA OVERNIGHT AS THE LOW MOVES INTO WISCONSIN...WITH LIFR POSSIBLE THU MORNING UNDER THE HEAVIEST SNOW. CONTINUED IFR/LIFR ON THU AS THE LOW EXITS TO THE EAST. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR TODAY...WINDS WILL DECREASE AND BECOME MORE SOUTHERLY THROUGH THE DAY. THE NEXT CHANCE FOR SIGNIFICANT WINDS WILL COME OVER THE WEEKEND AS A LOW PRESSURE SYSTEM MOVES NORTH OF LAKE SUPERIOR. THE STRONGEST WINDS WILL COME ON SUNDAY FROM THE NW...AND MAY REACH GALE FORCE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...MRD SYNOPSIS...JLB DISCUSSION...JLB AVIATION...MRD MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1126 AM EST WED DEC 28 2011 .UPDATE... LES CONTINUES ACROSS MARQUETTE AND ALGER COUNTIES AS THE FLOW REMAINS NORTHERLY OFF THE LAKE. WITH THE RIDGE AXIS OVERHEAD...THE FLOW SHOULD SHIFT TO THE SOUTH THIS AFTERNOON CAUSING THE LES TO END RATHER QUICKLY. SOME LIGHT SNOW/FLURRIES OVER MN ASSOCIATED WITH LEADING WARM ADVECTION WILL MOVE INTO WESTERN UPPER MI LATER THIS AFTERNOON BUT SHOULD BE OF LITTLE CONSEQUENCE. NO MAJOR CHANGES TO THE AFTERNOON FORECAST. BASED ON THE LATEST MODEL GUIDANCE...DID MAKE SOME SUBSTANTIAL CHANGES TO THE OVERNIGHT AND THURSDAY FORECAST FOR THE EASTERN PART OF THE FORECAST AREA. LOW PRESSURE OVER THE WESTERN DAKOTAS WILL MOVE TO THE WESTERN GREAT LAKES LATER TONIGHT INTO THURSDAY. THIS WILL PUT UPPER MICHIGAN IN A BROAD AREA OF ISENTROPIC LIFT/WARM ADVECTION. WITH THE BOUNDARY LAYER FLOW BEING SOUTH-SOUTHEAST LATE TONIGHT INTO THURSDAY COMBINED WITH 850MB TEMPS INITIALLY AROUND -11C (RISING TO -5C BY THU AFTN)...LAKE ENHANCED SNOW OFF OF LAKE MICHIGAN SEEMS MORE AND MORE LIKELY FOR SCHOOLCRAFT AND SOUTHERN LUCE COUNTIES. IN FACT...THE HIGHER RESOLUTION MODEL OUTPUT SUCH AS THE 4KM NAM NEST INDICATE UP TO 0.7 INCH OF LIQUID LATER TONIGHT INTO THURSDAY GENERALLY SOUTH OF M-28 IN SCHOOLCRAFT AND LUCE COUNTIES. STILL NEED TO TAKE A CLOSER LOOK AT THE 12Z RUNS...BUT GIVEN THAT THIS IS A GOOD SETUP FOR MODERATE TO HEAVY SNOW TO FALL OFF OF LAKE MICHIGAN IN SCHOOLCRAFT COUNTY...HAVE OPTED TO RAISE SNOW AMOUNTS TO A STORM TOTAL OF 3-6 INCHES AND RAISE POPS TO CATEGORICAL FOR THE SAME AREAS. MAY NEED TO ISSUE SOME HEADLINE TO ADDRESS THE SNOWFALL FOR THE EASTERN FORECAST AREA...HOWEVER IT IS STILL UNCLEAR IF A WARNING OR ADVISORY WILL BE NEEDED. THIS DECISION WILL LIKELY BE MADE LATER THIS AFTERNOON. OTHERWISE...THE REMAINDER OF THE AREA WILL SEE A GENERAL 1-3 INCH SNOWFALL WITH 700MB MIXING RATIO OF 2 G/KM OVERNIGHT INTO THU MORNING. && PREV DISCUSSION...ISSUED AT 623 AM EST WED DEC 28 2011... .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NE CANADA INTO ERN GREAT LAKES AND A FLAT RIDGE OVER THE WEST RESULTING IN NW FLOW FROM THE CANADIAN PRAIRIE THROUGH THE WRN GREAT LAKES. A SHEARED UPSTREAM SHORTWAVE TROUGH WAS MOVING INTO MANITOBA WHILE ANOTHER IN THE FAST WRLY FLOW OFF THE NE PACIFIC WAS LOCATED OVER SRN BC. AT THE SFC...A RIDGE EXTENDED FROM NRN ONTARIO INTO WRN WI LEAVING NRLY FLOW ACROSS LAKE SUPERIOR. 850 MB TEMPS AROUND -15C PROVIDED PLENTY OF INSTABILITY FOR LINGERING LES EVEN THROUGH VERY DRY AIR UPSTREAM AND INVERSION HEIGHTS DOWN TO AROUND 3K-4K FT. && .DISCUSSION... TODAY...EXPECT THAT THE LES WILL DIMINISH THIS MORNING AND END BY THIS AFTERNOON AS THE RIDGE MOVES ACROSS UPPER MICHIGAN AND WINDS BECOME OFFSHORE. ANY ACCUMULATIONS WITH SCT -SHSN INTO THE N CNTRL CWA THIS MORNING SHOULD AMOUNT TO LESS THAN AN INCH. RETURN SRLY FLOW WILL ALLOW MAX TEMPS TO REBOUND INTO THE UPPER TEENS AND LOWER 20S. TONIGHT INTO THU...MODELS SUGGEST THAT THE THE MID TO UPPER LEVEL FORCING WITH THE COMBINATION OF THE MANITOBA AND BC SHORTWAVES PASSING TO THE NORTH AND SOUTH OF UPPER MI WILL BE RELATIVELY MODEST. HOWEVER...AN AREA OF 285K-290K ISENTROPIC LIFT NORTH OF THE 850 MB LOW WILL SUPPORT WIDESPREAD LIGHT SNOW...MAINLY BTWN 06Z-18Z. WITH 2G-3G/KG AVBL...CONSENSUS QPF VALUES IN THE 0.1 TO 0.2...AND SNOW WATER RATIO VALUES NEAR 15/1...PREVIOUS FCST OF 1 TO 3 INCHES LOOKS ON TRACK. THERE IS GREATER UNCERTAINTY WITH THE POTENTIAL FOR HIGHER LAKE ENHANCED SNOW AMOUNTS WITH SRLY FLOW OFF OF LAKE MICHIGAN. THE HPC AND LCLY RUN HIGH RES WRF/ARW AS WELL AS THE CANADIAN REGIONAL GEM SUGGEST THAT A BAND MAY DEVELOP INTO WRN MACKINAC COUNTY LATE TONIGHT INTO EARLY THU AIDED BY LEVEL LEVEL CONV NEAR THE NW LOWER MI SHORE. THE BAND MAY SHIFT FARTHER WEST INTO SRN LUCE AND SRN SCHOOLCRAFT COUNTIES AS WINDS BACK IN RESPONSE TO THE WEAK SFC LOW MOVING TOWARD NRN LAKE MICHIGAN. ADDITIONAL SNOWFALL AMOUNTS OF SEVERAL INCHES COULD PUSH OVERALL AMOUNTS INTO THE ADVY CATEGORY IF THE BANDS DEVELOP AND PERSIST LONG ENOUGH AT ANY LOCATION. HOWEVER...CONFIDENCE IS BELOW AVERAGE WITH THESE DETAILS. THU NIGHT INTO FRI...LEFT OVER LIGHT SNOW OVER THE ERN PORTION OF THE CWA WILL GRADUALLY SLIDE OFF TO THE EAST AS WEAKER ISENTROPIC LIFT AND FGEN EXIT THE AREA. THE PATH OF THE NEXT SHORTWAVE REMAINS FAR ENOUGH SOUTH...PER GFS/ECMWF SO THAT FRI WILL REMAIN MAINLY DRY. SO...ONLY SLIGHT CHANCE POPS WERE INCLUDED. SAT THROUGH TUE...A PROGRESSIVE MID LEVEL TROUGH MOVES INTO THE PLAINS BRINGING WAA SAT. WITH LITTLE MOISTURE AVBL...LITTLE/NO MEASURABLE PCPN IS EXPECTED. THE GFS HAS TRENDED TOWARD THE GEM/ECMWF WITH TRANSITION TOWARD A MORE AMPLIFIED/MERIDIONAL PATTERN BY LATE SUN INTO MON. AN INFLUX OF COLD AIR (850 MB TEMPS DOWN INTO THE -17C TO -20C RANGE) BEHIND A COLD FRONT LATE SUN WITH DEEP MOISTURE AVAILABLE SHOULD BRING LES TO LOCATIONS FAVORED BY NW TO N FLOW TIL RIDING MOVES BACK IN BY TUE. && .AVIATION /FOR THE 12Z TAF ISSUANCE/... EXPECT LINGERING LES TO WANE THIS MORNING AS THE FLOW BECOMES MORE ANTICYCLONIC AND VERY DRY AIR UPSTREAM OF LAKE SUPERIOR HAS AN IMPACT. BUT WITH LINGERING LOW INVERSION BASE AND VERY CHILLY AIRMASS PASSING OVER LAKE SUPERIOR...EXPECT MVFR CIGS TO LINGER INTO THIS MORNING. AFTER THE LOW CLOUDS BREAK UP...VFR CONDITIONS WILL THEN PREVAIL THROUGH MUCH OF THE DAY. ANOTHER BAND OF THICKER CLOUDS/-SN WILL ARRIVE TOWARD EVENING WITH LOW END VFR/HIGH END MVFR CONDITIONS. THE BEST CHANCE FOR THE MVFR CIGS WILL BE AT THE FARTHER N CMX LOCATION. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR TODAY...WINDS WILL DECREASE AND BECOME MORE SOUTHERLY THROUGH THE DAY. THE NEXT CHANCE FOR SIGNIFICANT WINDS WILL COME OVER THE WEEKEND AS A LOW PRESSURE SYSTEM MOVES NORTH OF LAKE SUPERIOR. THE STRONGEST WINDS WILL COME ON SUNDAY FROM THE NW...AND MAY REACH GALE FORCE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...MRD SYNOPSIS...JLB DISCUSSION...JLB AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
623 AM EST WED DEC 28 2011 UPDATED AVIATION DISCUSSION FOR 12Z TAFS .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NE CANADA INTO ERN GREAT LAKES AND A FLAT RIDGE OVER THE WEST RESULTING IN NW FLOW FROM THE CANADIAN PRAIRIE THROUGH THE WRN GREAT LAKES. A SHEARED UPSTREAM SHORTWAVE TROUGH WAS MOVING INTO MANITOBA WHILE ANOTHER IN THE FAST WRLY FLOW OFF THE NE PACIFIC WAS LOCATED OVER SRN BC. AT THE SFC...A RIDGE EXTENDED FROM NRN ONTARIO INTO WRN WI LEAVING NRLY FLOW ACROSS LAKE SUPERIOR. 850 MB TEMPS AROUND -15C PROVIDED PLENTY OF INSTABILITY FOR LINGERING LES EVEN THROUGH VERY DRY AIR UPSTREAM AND INVERSION HEIGHTS DOWN TO AROUND 3K-4K FT. && .DISCUSSION... TODAY...EXPECT THAT THE LES WILL DIMINISH THIS MORNING AND END BY THIS AFTERNOON AS THE RIDGE MOVES ACROSS UPPER MICHIGAN AND WINDS BECOME OFFSHORE. ANY ACCUMULATIONS WITH SCT -SHSN INTO THE N CNTRL CWA THIS MORNING SHOULD AMOUNT TO LESS THAN AN INCH. RETURN SRLY FLOW WILL ALLOW MAX TEMPS TO REBOUND INTO THE UPPER TEENS AND LOWER 20S. TONIGHT INTO THU...MODELS SUGGEST THAT THE THE MID TO UPPER LEVEL FORCING WITH THE COMBINATION OF THE MANITOBA AND BC SHORTWAVES PASSING TO THE NORTH AND SOUTH OF UPPER MI WILL BE RELATIVELY MODEST. HOWEVER...AN AREA OF 285K-290K ISENTROPIC LIFT NORTH OF THE 850 MB LOW WILL SUPPORT WIDESPREAD LIGHT SNOW...MAINLY BTWN 06Z-18Z. WITH 2G-3G/KG AVBL...CONSENSUS QPF VALUES IN THE 0.1 TO 0.2...AND SNOW WATER RATIO VALUES NEAR 15/1...PREVIOUS FCST OF 1 TO 3 INCHES LOOKS ON TRACK. THERE IS GREATER UNCERTAINTY WITH THE POTENTIAL FOR HIGHER LAKE ENHANCED SNOW AMOUNTS WITH SRLY FLOW OFF OF LAKE MICHIGAN. THE HPC AND LCLY RUN HIGH RES WRF/ARW AS WELL AS THE CANADIAN REGIONAL GEM SUGGEST THAT A BAND MAY DEVELOP INTO WRN MACKINAC COUNTY LATE TONIGHT INTO EARLY THU AIDED BY LEVEL LEVEL CONV NEAR THE NW LOWER MI SHORE. THE BAND MAY SHIFT FARTHER WEST INTO SRN LUCE AND SRN SCHOOLCRAFT COUNTIES AS WINDS BACK IN RESPONSE TO THE WEAK SFC LOW MOVING TOWARD NRN LAKE MICHIGAN. ADDITIONAL SNOWFALL AMOUNTS OF SEVERAL INCHES COULD PUSH OVERALL AMOUNTS INTO THE ADVY CATEGORY IF THE BANDS DEVELOP AND PERSIST LONG ENOUGH AT ANY LOCATION. HOWEVER...CONFIDENCE IS BELOW AVERAGE WITH THESE DETAILS. THU NIGHT INTO FRI...LEFT OVER LIGHT SNOW OVER THE ERN PORTION OF THE CWA WILL GRADUALLY SLIDE OFF TO THE EAST AS WEAKER ISENTROPIC LIFT AND FGEN EXIT THE AREA. THE PATH OF THE NEXT SHORTWAVE REMAINS FAR ENOUGH SOUTH...PER GFS/ECMWF SO THAT FRI WILL REMAIN MAINLY DRY. SO...ONLY SLIGHT CHANCE POPS WERE INCLUDED. SAT THROUGH TUE...A PROGRESSIVE MID LEVEL TROUGH MOVES INTO THE PLAINS BRINGING WAA SAT. WITH LITTLE MOISTURE AVBL...LITTLE/NO MEASURABLE PCPN IS EXPECTED. THE GFS HAS TRENDED TOWARD THE GEM/ECMWF WITH TRANSITION TOWARD A MORE AMPLIFIED/MERIDIONAL PATTERN BY LATE SUN INTO MON. AN INFLUX OF COLD AIR (850 MB TEMPS DOWN INTO THE -17C TO -20C RANGE) BEHIND A COLD FRONT LATE SUN WITH DEEP MOISTURE AVAILABLE SHOULD BRING LES TO LOCATIONS FAVORED BY NW TO N FLOW TIL RIDING MOVES BACK IN BY TUE. && .AVIATION /FOR THE 12Z TAF ISSUANCE/... EXPECT LINGERING LES TO WANE THIS MORNING AS THE FLOW BECOMES MORE ANTICYCLONIC AND VERY DRY AIR UPSTREAM OF LAKE SUPERIOR HAS AN IMPACT. BUT WITH LINGERING LOW INVERSION BASE AND VERY CHILLY AIRMASS PASSING OVER LAKE SUPERIOR...EXPECT MVFR CIGS TO LINGER INTO THIS MORNING. AFTER THE LOW CLOUDS BREAK UP...VFR CONDITIONS WILL THEN PREVAIL THROUGH MUCH OF THE DAY. ANOTHER BAND OF THICKER CLOUDS/-SN WILL ARRIVE TOWARD EVENING WITH LOW END VFR/HIGH END MVFR CONDITIONS. THE BEST CHANCE FOR THE MVFR CIGS WILL BE AT THE FARTHER N CMX LOCATION. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR TODAY...WINDS WILL DECREASE AND BECOME MORE SOUTHERLY THROUGH THE DAY. THE NEXT CHANCE FOR SIGNIFICANT WINDS WILL COME OVER THE WEEKEND AS A LOW PRESSURE SYSTEM MOVES NORTH OF LAKE SUPERIOR. THE STRONGEST WINDS WILL COME ON SUNDAY FROM THE NW...AND MAY REACH GALE FORCE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB DISCUSSION...JLB AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
552 AM EST WED DEC 28 2011 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NE CANADA INTO ERN GREAT LAKES AND A FLAT RIDGE OVER THE WEST RESULTING IN NW FLOW FROM THE CANADIAN PRAIRIE THROUGH THE WRN GREAT LAKES. A SHEARED UPSTREAM SHORTWAVE TROUGH WAS MOVING INTO MANITOBA WHILE ANOTHER IN THE FAST WRLY FLOW OFF THE NE PACIFIC WAS LOCATED OVER SRN BC. AT THE SFC...A RIDGE EXTENDED FROM NRN ONTARIO INTO WRN WI LEAVING NRLY FLOW ACROSS LAKE SUPERIOR. 850 MB TEMPS AROUND -15C PROVIDED PLENTY OF INSTABILITY FOR LINGERING LES EVEN THROUGH VERY DRY AIR UPSTREAM AND INVERSION HEIGHTS DOWN TO AROUND 3K-4K FT. && .DISCUSSION... TODAY...EXPECT THAT THE LES WILL DIMINISH THIS MORNING AND END BY THIS AFTERNOON AS THE RIDGE MOVES ACROSS UPPER MICHIGAN AND WINDS BECOME OFFSHORE. ANY ACCUMULATIONS WITH SCT -SHSN INTO THE N CNTRL CWA THIS MORNING SHOULD AMOUNT TO LESS THAN AN INCH. RETURN SRLY FLOW WILL ALLOW MAX TEMPS TO REBOUND INTO THE UPPER TEENS AND LOWER 20S. TONIGHT INTO THU...MODELS SUGGEST THAT THE THE MID TO UPPER LEVEL FORCING WITH THE COMBINATION OF THE MANITOBA AND BC SHORTWAVES PASSING TO THE NORTH AND SOUTH OF UPPER MI WILL BE RELATIVELY MODEST. HOWEVER...AN AREA OF 285K-290K ISENTROPIC LIFT NORTH OF THE 850 MB LOW WILL SUPPORT WIDESPREAD LIGHT SNOW...MAINLY BTWN 06Z-18Z. WITH 2G-3G/KG AVBL...CONSENSUS QPF VALUES IN THE 0.1 TO 0.2...AND SNOW WATER RATIO VALUES NEAR 15/1...PREVIOUS FCST OF 1 TO 3 INCHES LOOKS ON TRACK. THERE IS GREATER UNCERTAINTY WITH THE POTENTIAL FOR HIGHER LAKE ENHANCED SNOW AMOUNTS WITH SRLY FLOW OFF OF LAKE MICHIGAN. THE HPC AND LCLY RUN HIGH RES WRF/ARW AS WELL AS THE CANADIAN REGIONAL GEM SUGGEST THAT A BAND MAY DEVELOP INTO WRN MACKINAC COUNTY LATE TONIGHT INTO EARLY THU AIDED BY LEVEL LEVEL CONV NEAR THE NW LOWER MI SHORE. THE BAND MAY SHIFT FARTHER WEST INTO SRN LUCE AND SRN SCHOOLCRAFT COUNTIES AS WINDS BACK IN RESPONSE TO THE WEAK SFC LOW MOVING TOWARD NRN LAKE MICHIGAN. ADDITIONAL SNOWFALL AMOUNTS OF SEVERAL INCHES COULD PUSH OVERALL AMOUNTS INTO THE ADVY CATEGORY IF THE BANDS DEVELOP AND PERSIST LONG ENOUGH AT ANY LOCATION. HOWEVER...CONFIDENCE IS BELOW AVERAGE WITH THESE DETAILS. THU NIGHT INTO FRI...LEFT OVER LIGHT SNOW OVER THE ERN PORTION OF THE CWA WILL GRADUALLY SLIDE OFF TO THE EAST AS WEAKER ISENTROPIC LIFT AND FGEN EXIT THE AREA. THE PATH OF THE NEXT SHORTWAVE REMAINS FAR ENOUGH SOUTH...PER GFS/ECMWF SO THAT FRI WILL REMAIN MAINLY DRY. SO...ONLY SLIGHT CHANCE POPS WERE INCLUDED. SAT THROUGH TUE...A PROGRESSIVE MID LEVEL TROUGH MOVES INTO THE PLAINS BRINGING WAA SAT. WITH LITTLE MOISTURE AVBL...LITTLE/NO MEASURABLE PCPN IS EXPECTED. THE GFS HAS TRENDED TOWARD THE GEM/ECMWF WITH TRANSITION TOWARD A MORE AMPLIFIED/MERIDIONAL PATTERN BY LATE SUN INTO MON. AN INFLUX OF COLD AIR (850 MB TEMPS DOWN INTO THE -17C TO -20C RANGE) BEHIND A COLD FRONT LATE SUN WITH DEEP MOISTURE AVAILABLE SHOULD BRING LES TO LOCATIONS FAVORED BY NW TO N FLOW TIL RIDING MOVES BACK IN BY TUE. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... EXPECT LINGERING LES TO WANE EARLY THIS MRNG AS THE FLOW BECOMES MORE ACYC AND VERY DRY AIR UPSTREAM OF LK SUP HAS AN IMPACT. BUT WITH LINGERING LO INVRN BASE AND VERY CHILLY AIRMASS PASSING OVER LK SUP...EXPECT MVFR CIGS TO LINGER THRU SUNRISE. THE CLDS MAY BREAK UP A BIT EARLIER AT IWD CLOSER TO INCOMING HI PRES RDG. AFT THE LO CLDS BREAK UP...VFR CONDITIONS WL THEN PREVAIL THRU MUCH OF THE DAY. ANOTHER BAND OF THICKER CLDS/-SN WL ARRIVE TOWARD EVNG WITH LO END VFR/HI END MVFR CONDITIONS. THE BEST CHC FOR THE MVFR CIGS WL BE AT THE FARTHER N CMX LOCATION. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR TODAY...WINDS WILL DECREASE AND BECOME MORE SOUTHERLY THROUGH THE DAY. THE NEXT CHANCE FOR SIGNIFICANT WINDS WILL COME OVER THE WEEKEND AS A LOW PRESSURE SYSTEM MOVES NORTH OF LAKE SUPERIOR. THE STRONGEST WINDS WILL COME ON SUNDAY FROM THE NW...AND MAY REACH GALE FORCE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB DISCUSSION...JLB AVIATION...KC MARINE...TITUS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
352 PM CST WED DEC 28 2011 .DISCUSSION... SUMMARY...PATTERN IS A BIT MORE ACTIVE OVER THE NEXT SEVERAL DAYS IN TERMS OF CHANCES OF PRECIPITATION THAN IT HAS BEEN IN QUITE SOME TIME. OVERALL...THE OUTLOOK REMAINS WARM SO THE PRECIP EVENTS EXPECTED TONIGHT...THURSDAY NIGHT AND SATURDAY NIGHT WILL LIKELY HAVE SOME LIQUID PRECIPITATION ASSOCIATED WITH EACH OF THEM. NO MAJOR SYSTEMS EXPECTED AND MAXIMUM QPF WITH EACH EVENT SHOULD LARGELY BE BELOW A QUARTER INCH...A COUPLE OUTLIER RUNS OF THE NAM/GEM WOULD SUGGEST HIGHER QPF TOTALS WITH THE THURSDAY NIGHT AND SATURDAY NIGHT SYSTEMS. THE INTERIOR OF CANADA HAS COOLED SINCE THE LAST TIME I WAS ON A FORECAST SHIFT LATE LAST WEEK...BUT STILL NO TRUE ARCTIC AIR ENCROACHING ON THE US CONUS. THE ARCTIC AIR IS STILL BEING CONFINED TO THE HIGHER LATITUDES...LARGELY ABOVE 55-60 DEGREES NORTH. PACIFIC AIR MASSES WILL CONTINUE TO IMPACT THE US THROUGH THE END OF THE YEAR. PROGRESSIVE UPPER FLOW WILL BE FEATURED AS A SERIES OF DISTURBANCES SURGE FROM THE NORTHEASTERN PACIFIC AND INTO THE PACIFIC NORTHWEST. THE SOUTHWARD EXTENT OF THIS UPPER TROUGH SHOULD BE LIMITED BY A RIDGE ACROSS THE SOUTHWEST US. AS A RESULT...THE SWATH OF PRECIPITATION SHOULD NOT EXTEND MUCH FARTHER SOUTH THAN 40 DEGREES NORTH. THIS WILL KEEP MN AND WI UNDER THE GUN FOR A FEW LIGHT PRECIPITATION EVENTS OVER THE COMING DAYS. THE FAST MOVING FLOW ALOFT WILL KEEP UNSETTLED CONDITIONS IN PLACE FOR MUCH OF THE PACIFIC NORTHWEST...NORTHERN ROCKIES AND UPPER MISSISSIPPI VALLEY THROUGH THE WEEKEND. THE FIRST IN A PAIR OF SYSTEMS IS CURRENTLY MOVING OUT OF THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS. LIGHT RAIN IS RAPIDLY PUSHING INTO THE EASTERN DAKOTAS LATE THIS AFTERNOON AND THE HRRR TREND IS TAKE THE LIGHT RAIN INTO WESTERN MN BETWEEN 00-03Z. IF THE CURRENT TRENDS HOLD...MOST OF THE PRECIP WILL PUSH OUT OF THE FORECAST AREA BETWEEN 06-09Z...A BIT FASTER THAN THE CURRENT FORECAST INDICATES. ALSO SOME QUESTION WHETHER OR NOT THE MIXED PRECIPITATION WILL REALLY PAN OUT IN PARTS OF CENTRAL/SOUTHERN MN. COOLING WILL BE TOUGH WITH CLOUD COVER AND WEAK WARM AIR ADVECTION. IT MIGHT END UP BEING NEARLY ALL LIGHT RAIN RATHER THAN SNOW OR FREEZING RAIN. IN THE EXTENDED...INCREASINGLY MERIDIONAL FLOW WILL LEAD TO MORE AMPLIFIED TROUGHS ACROSS THE EASTERN PACIFIC THROUGH THE GREAT LAKES WITH RIDGING SANDWICHED IN BETWEEN. MOST OF THE GUIDANCE AGREES ON THIS PATTERN...OUTSIDE THE 00Z GFS WHICH WAS BROAD AND FLAT WITH THE EASTERN TROUGH DESPITE ITS AMPLIFIED RIDGE UPSTREAM. && .AVIATION.../18Z TAF ISSUANCE/ FIRST SHOT OF WAA SNOW SHOWERS/FLURRIES MOVING THROUGH EASTERN AREAS AT THIS TIME. SHOULD EXIT THE AREA THROUGH 19Z. MAIN CONCERN IS PRECIPITATION DEVELOPMENT OVER THE NORTHERN AND EASTERN AREAS OF THE AREA OVERNIGHT. NEXT WAVE MOVING THROUGH NORTHEASTERN MONTANA THIS AFTERNOON AND SHOULD SPREAD MORE MID/HIGH LEVEL CLOUDS INTO THE WEST THROUGH 00Z. FORCING IS STRONG BUT DEEP LAYER MOISTURE IS RATHER LIMITED. SHOULD STILL SEE SOME LIGHT QPF ALONG AND NORTH OF THE SFC LOW TRACK. THIS WOULD AFFECT ALL TAFS WITH THE EXCEPTION OF KRWF OVERNIGHT. PRECIPITATION TYPE ALSO A PROBLEM...AS WARM SURGE MOVES IN WITH THE SURFACE LOW. -FZRA POSSIBLE...AT LEAST BRIEFLY...ALONG AND NORTH OF THE LOW TRACK. SREF FREEZING RAIN PROBS INCREASE TO 30% INTO WEST CENTRAL WI LATER TONIGHT. CEILINGS ARE EXPECTED TO DROP TO MVFR AS PRECIPITATION DEVELOPS AND COLD FRONT DROPPING IN BEHIND...SHOULD CONTINUE LOW END MVFR CONDITIONS OVER MUCH OF THE AREA INTO THURSDAY MORNING. SOUTHERLY SURFACE WINDS BECOMING NORTHWEST AS LOW EXITS REGION. SHOULD REMAIN AROUND 10 KNOTS OR LESS MOST LOCATIONS. KMSP...MID LEVEL CLOUDS EXITING THE REGION WITH MORE MID/HIGH LEVEL CLOUDS MOVING IN LATE AFTERNOON FROM THE WEST. STILL LOOKING AT POSSIBILITY OF LIGHT QPF ASSOCIATED WITH THE WAVE MOVING IN LATER TONIGHT. BEST SHOT AT PCPN STILL LOOKS LIKE 05Z-08Z. TYPE COULD BE -RASN AND DEPENDING ON SURFACE TEMP...-FZRA A POSSIBILITY. LOW CONFIDENCE OF THIS HAPPENING AT THE AIRPORT AT THIS TIME...MORE LIKELY NORTH OF THE AREA. MVFR CONDS WILL DEVELOP WITH PRECIPITATION AND LINGER THROUGH THE MORNING AS COLD AIR ADVECTION DEVELOPS BEHIND SURFACE LOW AND COLD FRONT. SOUTHERLY SURFACE WINDS BECOMING MORE NORTHWEST BY THURSDAY MORNING WITH PASSAGE OF SURFACE LOW AND COLD FRONT. NEXT WAVE MOVING IN OVER WESTERN MN LATE THURSDAY AFTERNOON AND AFFECTING THE AREA MAINLY AFTER 03Z FRI. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ CLF/DWE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1218 PM CST WED DEC 28 2011 .AVIATION.../18Z TAF ISSUANCE/ AN AREA OF LOW CLOUDS AND VERY LIGHT SNOW WILL CONTINUE TO MOVE OFF TO THE EAST THIS AFTERNOON. HOWEVER ANOTHER AREA OF CLOUD COVER WILL REPLACE IT OVERNIGHT TONIGHT AS ANOTHER SYSTEM FROM CANADA TRACKS EWSEWD ACROSS THE CWA. LIGHT SNOW WILL DEVELOP ACROSS OUR WRN ZONES THIS EVENING...THEN SPREAD EWD OVERNIGHT TO AFFECT THE TWIN PORTS...IRON RANGE AND NWRN WI. VSBYS WITHIN THE SNOWFALL WILL BE IN THE IFR/MVFR RANGE WHILE CIGS SHOULD BE IN THE MVFR RANGE. THE SNOW WILL QUICKLY TAPER OFF TO SCATTERED LIGHT SNOW SHOWERS THURSDAY MORNING BEFORE ENDING THURSDAY AFTERNOON. && .PREV DISCUSSION... /ISSUED 1211 PM CST WED DEC 28 2011/ UPDATE... SNOW AREA SPREADING EAST AS FORECAST AND HAVE UPDATED THE FORECAST TO TAKE OUT THE SNOW FROM THE AREA WEST OF A LINE FROM INL THROUGH DLH. SATELLITE SHOWS CLEAR SKIES BEHIND THE SNOW...BUT AREA OF LOW CLOUDS WILL SPREAD SOUTH INTO NORTHERN MN....WHILE WAA CLOUDS WILL MOVE IN THR THE WEST LATE THIS AFTERNOON. PREV DISCUSSION... /ISSUED 356 AM CST WED DEC 28 2011/ SHORT TERM...THE MAIN FORECAST CONCERN IN THE SHORT TERM IS THE AMOUNT AND LOCATION OF ACCUMULATING SNOWFALL TODAY THROUGH TONIGHT. AT 330 AM...CLOUDS WERE INCREASING AHEAD OF A WEAK SHORTWAVE AND UP[PER LEVEL JET MAX TRAVERSING ACROSS MN. STRONG LOW LEVEL WAA AND THETA-E ADVECTION WAS HELPING TO GENERATE LIGHT SNOW ACROSS WESTERN MN DESPITE INITIALLY DRY LOW LEVEL AIR. THE HRRR RAPID REFRESH WAS DEPICTING THE AREA OF CLOUDS/LIGHT SNOW FAIRLY WELL. THE SHORTWAVE AND 100+ KNOT UPPER LEVEL JET MAX WILL CONTINUE TO PUSH ACROSS THE NORTHLAND TODAY...PUSHING INTO THE WESTERN GREAT LAKES BY THIS AFTERNOON. THE LATEST HRRR ACTUALLY SHOWS THE RETURNS DIMINISHING FOR A TIME THIS EARLY MORNING...BEFORE INCREASING A BIT AGAIN AS THEY REACH NE MN LATER IN THE MORNING. THINK THERE IS A CHANCE FOR ABOUT A HALF INCH OF SNOWFALL IN SPOTS TODAY. COULD SEE A BIT MORE ALONG THE SAWTOOTH MOUNTAINS OF THE NORTH SHORE...AS WINDS COME AROUND TO THE EAST AND SUPPORT LAKE EFFECT SNOW SHOWERS. A STRONGER SYSTEM WILL MOVE IN TONIGHT...AND QUICKLY EXIT THE REGION ON THURSDAY. HAVE SHIFTED THE FOCUS FOR ACCUMULATING SNOWFALL A BIT TO THE SOUTH BASED ON THE LATEST 00Z MODEL RUNS. CURRENT THINKING IS THAT THERE WILL BE A STRIPE OF 1 TO 3 INCHES FROM THE NORTHERN BRAINERD LAKES REGION...THROUGH THE TWIN PORTS AND INTO NW WI. ALSO CANNOT RULE OUT A NARROW STRIPE OF 2 TO 4 INCHES OR POSSIBLY A BIT MORE AS THE SYSTEM DROPS TO THE SOUTHEAST AND LAYS DOWN A SWATH OF ACCUMULATING SNOWFALL. THE NORTH SHORE SHOULD ALSO SEE HIGHER AMOUNTS DUE TO LAKE EFFECT/LAKE ENHANCEMENT. IN TERMS OF SURFACE LOW PRESSURE...THE MODELS ARE FAIRLY SIMILAR...BUT QPF AMOUNTS AND LOCATION DO VARY BETWEEN THE ECMWF/NAM/GFS AND GEM. WILL TAKE A CONSENSUS SOLUTION. MAY NEED TO BUMP UP AMOUNTS IN LATER FORECAST PACKAGES. IN THE GRIDS...CURRENTLY HAVE AMOUNTS SIMILAR TO WHAT IS MENTIONED ABOVE. THINK THE SYSTEM WILL BE FAIRLY EFFICIENT AT RINGING OUT AVAILABLE MOISTURE. THE LOW PRESSURE SYSTEM WILL MOVE OUT OF THE REGION ON THURSDAY...WITH A BIT OF A BREAK BEFORE THE NEXT SYSTEM ARRIVES THURSDAY NIGHT. THE NAM SOLUTION WOULD SUPPORT HIGHER POPS FOR THURSDAY NIGHT...BUT THE ECMWF/GFS KEEP THE ACCUMULATING SNOW GENERALLY WEST AND SOUTH OF THE CWA. LONG TERM...FRIDAY THROUGH TUESDAY. FRIDAY...THE LONG TERM PERIOD BEGINS WITH LOW CHANCES OF SNOWFALL...MAINLY DUE TO THE GFS SHOWING A TROUGH MOVING THROUGH THE NORTHLAND. IT LOOKS LIKE A RIDGE WILL MOVE INTO THE REGION FRIDAY NIGHT WITH SOUTHERLY WINDS DEVELOPING BY SATURDAY MORNING. SATURDAY...IT LOOKS LIKE A RELATIVELY WARM DAY. SOUTHWESTERLY WINDS WILL DEVELOP AS A LOW PRESSURE SYSTEM MOVES FROM CENTRAL MANITOBA TO WESTERN ONTARIO. THERE MAY BE SOME LIGHT PCPN ACROSS THE NORTHLAND. CONSIDERING THE WARMER SURFACE TEMPERATURES AND TEMPERATURES ALOFT...FORECASTED A POSSIBLE MIXTURE OF RAIN AND SNOW. PLUS...MODEL SOUNDINGS GENERALLY HAD SATURATION ALOFT TO ONLY ABOUT -5 DEGREES CELSIUS OR LESS UNTIL LATER IN THE EVENING WHEN THE COLDER AIR IS USHERED INTO THE NORTHLAND. SO WOULD THINK THE PCPN WOULD LIKELY TURN BACK TO SNOW SATURDAY NIGHT. SUNDAY AND MONDAY...THE BEGINNING OF NEXT WEEK SHOULD START OFF COLD. IT LOOKS LIKE THE POSSIBILITY OF LINGERING SYNOPTIC SNOW ACROSS THE NORTHLAND...AS WELL AS LAKE EFFECT SNOWFALL ALONG PARTS OF THE SOUTH SHORE. THE MODELS INDICATE VERY COLD 850 HPA WILL WRAP INTO THE NORTHLAND...AS LOW AS -16 DEGREES CELSIUS. THIS SHOULD MAKE FOR A SOLID TEMPERATURE DIFFERENCE BETWEEN 850 HPA AND THE LAKE SURFACE TEMPERATURE...WHICH IS AROUND 4 DEGREES CELSIUS. && .POINT TEMPS/POPS... DLH 27 19 29 21 / 30 70 20 20 INL 26 12 26 15 / 30 30 10 20 BRD 32 25 33 24 / 10 60 20 30 HYR 28 20 32 23 / 30 70 30 30 ASX 29 20 33 24 / 20 70 30 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...BERDES
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1211 PM CST WED DEC 28 2011 .UPDATE... SNOW AREA SPREADING EAST AS FORECAST AND HAVE UPDATED THE FORECAST TO TAKE OUT THE SNOW FROM THE AREA WEST OF A LINE FROM INL THROUGH DLH. SATELLITE SHOWS CLEAR SKIES BEHIND THE SNOW...BUT AREA OF LOW CLOUDS WILL SPREAD SOUTH INTO NORTHERN MN....WHILE WAA SLOUDS WILL MOVE IN THR THE WEST LATE THIS AFTERNOON. && PREV DISCUSSION... /ISSUED 356 AM CST WED DEC 28 2011/ SHORT TERM...THE MAIN FORECAST CONCERN IN THE SHORT TERM IS THE AMOUNT AND LOCATION OF ACCUMULATING SNOWFALL TODAY THROUGH TONIGHT. AT 330 AM...CLOUDS WERE INCREASING AHEAD OF A WEAK SHORTWAVE AND UP[PER LEVEL JET MAX TRAVERSING ACROSS MN. STRONG LOW LEVEL WAA AND THETA-E ADVECTION WAS HELPING TO GENERATE LIGHT SNOW ACROSS WESTERN MN DESPITE INITIALLY DRY LOW LEVEL AIR. THE HRRR RAPID REFRESH WAS DEPICTING THE AREA OF CLOUDS/LIGHT SNOW FAIRLY WELL. THE SHORTWAVE AND 100+ KNOT UPPER LEVEL JET MAX WILL CONTINUE TO PUSH ACROSS THE NORTHLAND TODAY...PUSHING INTO THE WESTERN GREAT LAKES BY THIS AFTERNOON. THE LATEST HRRR ACTUALLY SHOWS THE RETURNS DIMINISHING FOR A TIME THIS EARLY MORNING...BEFORE INCREASING A BIT AGAIN AS THEY REACH NE MN LATER IN THE MORNING. THINK THERE IS A CHANCE FOR ABOUT A HALF INCH OF SNOWFALL IN SPOTS TODAY. COULD SEE A BIT MORE ALONG THE SAWTOOTH MOUNTAINS OF THE NORTH SHORE...AS WINDS COME AROUND TO THE EAST AND SUPPORT LAKE EFFECT SNOW SHOWERS. A STRONGER SYSTEM WILL MOVE IN TONIGHT...AND QUICKLY EXIT THE REGION ON THURSDAY. HAVE SHIFTED THE FOCUS FOR ACCUMULATING SNOWFALL A BIT TO THE SOUTH BASED ON THE LATEST 00Z MODEL RUNS. CURRENT THINKING IS THAT THERE WILL BE A STRIPE OF 1 TO 3 INCHES FROM THE NORTHERN BRAINERD LAKES REGION...THROUGH THE TWIN PORTS AND INTO NW WI. ALSO CANNOT RULE OUT A NARROW STRIPE OF 2 TO 4 INCHES OR POSSIBLY A BIT MORE AS THE SYSTEM DROPS TO THE SOUTHEAST AND LAYS DOWN A SWATH OF ACCUMULATING SNOWFALL. THE NORTH SHORE SHOULD ALSO SEE HIGHER AMOUNTS DUE TO LAKE EFFECT/LAKE ENHANCEMENT. IN TERMS OF SURFACE LOW PRESSURE...THE MODELS ARE FAIRLY SIMILAR...BUT QPF AMOUNTS AND LOCATION DO VARY BETWEEN THE ECMWF/NAM/GFS AND GEM. WILL TAKE A CONSENSUS SOLUTION. MAY NEED TO BUMP UP AMOUNTS IN LATER FORECAST PACKAGES. IN THE GRIDS...CURRENTLY HAVE AMOUNTS SIMILAR TO WHAT IS MENTIONED ABOVE. THINK THE SYSTEM WILL BE FAIRLY EFFICIENT AT RINGING OUT AVAILABLE MOISTURE. THE LOW PRESSURE SYSTEM WILL MOVE OUT OF THE REGION ON THURSDAY...WITH A BIT OF A BREAK BEFORE THE NEXT SYSTEM ARRIVES THURSDAY NIGHT. THE NAM SOLUTION WOULD SUPPORT HIGHER POPS FOR THURSDAY NIGHT...BUT THE ECMWF/GFS KEEP THE ACCUMULATING SNOW GENERALLY WEST AND SOUTH OF THE CWA. LONG TERM...FRIDAY THROUGH TUESDAY. FRIDAY...THE LONG TERM PERIOD BEGINS WITH LOW CHANCES OF SNOWFALL...MAINLY DUE TO THE GFS SHOWING A TROUGH MOVING THROUGH THE NORTHLAND. IT LOOKS LIKE A RIDGE WILL MOVE INTO THE REGION FRIDAY NIGHT WITH SOUTHERLY WINDS DEVELOPING BY SATURDAY MORNING. SATURDAY...IT LOOKS LIKE A RELATIVELY WARM DAY. SOUTHWESTERLY WINDS WILL DEVELOP AS A LOW PRESSURE SYSTEM MOVES FROM CENTRAL MANITOBA TO WESTERN ONTARIO. THERE MAY BE SOME LIGHT PCPN ACROSS THE NORTHLAND. CONSIDERING THE WARMER SURFACE TEMPERATURES AND TEMPERATURES ALOFT...FORECASTED A POSSIBLE MIXTURE OF RAIN AND SNOW. PLUS...MODEL SOUNDINGS GENERALLY HAD SATURATION ALOFT TO ONLY ABOUT -5 DEGREES CELSIUS OR LESS UNTIL LATER IN THE EVENING WHEN THE COLDER AIR IS USHERED INTO THE NORTHLAND. SO WOULD THINK THE PCPN WOULD LIKELY TURN BACK TO SNOW SATURDAY NIGHT. SUNDAY AND MONDAY...THE BEGINNING OF NEXT WEEK SHOULD START OFF COLD. IT LOOKS LIKE THE POSSIBILITY OF LINGERING SYNOPTIC SNOW ACROSS THE NORTHLAND...AS WELL AS LAKE EFFECT SNOWFALL ALONG PARTS OF THE SOUTH SHORE. THE MODELS INDICATE VERY COLD 850 HPA WILL WRAP INTO THE NORTHLAND...AS LOW AS -16 DEGREES CELSIUS. THIS SHOULD MAKE FOR A SOLID TEMPERATURE DIFFERENCE BETWEEN 850 HPA AND THE LAKE SURFACE TEMPERATURE...WHICH IS AROUND 4 DEGREES CELSIUS. && .POINT TEMPS/POPS... DLH 27 19 29 21 / 30 70 20 20 INL 26 12 26 15 / 30 30 10 20 BRD 32 25 33 24 / 10 60 20 30 HYR 28 20 32 23 / 30 70 30 30 ASX 29 20 33 24 / 20 70 30 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...CLC LONG TERM....BERDES
AREA FORECAST DISCUSSION
NWS DULUTH MN
553 AM CST WED DEC 28 2011 .AVIATION [12Z TAF ISSUANCE]... A SHORTWAVE MOVING THROUGH MANITOBA AND THE NORTHERN PLAINS WILL BRING BKN/OVC MVFR CEILINGS TO NORTHEASTERN MINNESOTA AND NORTHWESTERN WISCONSIN THIS MORNING. THERE WILL BE A BRIEF THREE TO FOUR HOUR PERIOD OF LIGHT SNOWFALL WITH THIS SHORTWAVE PASSAGE. THERE MAY BE PERIODS OF MVFR VIS WITH THE SNOW. MVFR OR LOW END VFR CIGS WILL LIKELY REMAIN THROUGH THIS AFTERNOON...BUT THERE IS A CHANCE OF SOME CLEARING. A CANADIAN CLIPPER WILL SWING THROUGH CENTRAL MINNESOTA TONIGHT. IT WILL PROLONG MVFR CIGS THROUGH TONIGHT AND BRING MORE LIGHT SNOW. MVFR VSBYS ARE POSSIBLE WITH THE SNOW. LIGHT WINDS ARE EXPECTED THROUGH TOMORROW MORNING. && .PREV DISCUSSION... /ISSUED 356 AM CST WED DEC 28 2011/ SHORT TERM...THE MAIN FORECAST CONCERN IN THE SHORT TERM IS THE AMOUNT AND LOCATION OF ACCUMULATING SNOWFALL TODAY THROUGH TONIGHT. AT 330 AM...CLOUDS WERE INCREASING AHEAD OF A WEAK SHORTWAVE AND UP[PER LEVEL JET MAX TRAVERSING ACROSS MN. STRONG LOW LEVEL WAA AND THETA-E ADVECTION WAS HELPING TO GENERATE LIGHT SNOW ACROSS WESTERN MN DESPITE INITIALLY DRY LOW LEVEL AIR. THE HRRR RAPID REFRESH WAS DEPICTING THE AREA OF CLOUDS/LIGHT SNOW FAIRLY WELL. THE SHORTWAVE AND 100+ KNOT UPPER LEVEL JET MAX WILL CONTINUE TO PUSH ACROSS THE NORTHLAND TODAY...PUSHING INTO THE WESTERN GREAT LAKES BY THIS AFTERNOON. THE LATEST HRRR ACTUALLY SHOWS THE RETURNS DIMINISHING FOR A TIME THIS EARLY MORNING...BEFORE INCREASING A BIT AGAIN AS THEY REACH NE MN LATER IN THE MORNING. THINK THERE IS A CHANCE FOR ABOUT A HALF INCH OF SNOWFALL IN SPOTS TODAY. COULD SEE A BIT MORE ALONG THE SAWTOOTH MOUNTAINS OF THE NORTH SHORE...AS WINDS COME AROUND TO THE EAST AND SUPPORT LAKE EFFECT SNOW SHOWERS. A STRONGER SYSTEM WILL MOVE IN TONIGHT...AND QUICKLY EXIT THE REGION ON THURSDAY. HAVE SHIFTED THE FOCUS FOR ACCUMULATING SNOWFALL A BIT TO THE SOUTH BASED ON THE LATEST 00Z MODEL RUNS. CURRENT THINKING IS THAT THERE WILL BE A STRIPE OF 1 TO 3 INCHES FROM THE NORTHERN BRAINERD LAKES REGION...THROUGH THE TWIN PORTS AND INTO NW WI. ALSO CANNOT RULE OUT A NARROW STRIPE OF 2 TO 4 INCHES OR POSSIBLY A BIT MORE AS THE SYSTEM DROPS TO THE SOUTHEAST AND LAYS DOWN A SWATH OF ACCUMULATING SNOWFALL. THE NORTH SHORE SHOULD ALSO SEE HIGHER AMOUNTS DUE TO LAKE EFFECT/LAKE ENHANCEMENT. IN TERMS OF SURFACE LOW PRESSURE...THE MODELS ARE FAIRLY SIMILAR...BUT QPF AMOUNTS AND LOCATION DO VARY BETWEEN THE ECMWF/NAM/GFS AND GEM. WILL TAKE A CONSENSUS SOLUTION. MAY NEED TO BUMP UP AMOUNTS IN LATER FORECAST PACKAGES. IN THE GRIDS...CURRENTLY HAVE AMOUNTS SIMILAR TO WHAT IS MENTIONED ABOVE. THINK THE SYSTEM WILL BE FAIRLY EFFICIENT AT RINGING OUT AVAILABLE MOISTURE. THE LOW PRESSURE SYSTEM WILL MOVE OUT OF THE REGION ON THURSDAY...WITH A BIT OF A BREAK BEFORE THE NEXT SYSTEM ARRIVES THURSDAY NIGHT. THE NAM SOLUTION WOULD SUPPORT HIGHER POPS FOR THURSDAY NIGHT...BUT THE ECMWF/GFS KEEP THE ACCUMULATING SNOW GENERALLY WEST AND SOUTH OF THE CWA. LONG TERM...FRIDAY THROUGH TUESDAY. FRIDAY...THE LONG TERM PERIOD BEGINS WITH LOW CHANCES OF SNOWFALL...MAINLY DUE TO THE GFS SHOWING A TROUGH MOVING THROUGH THE NORTHLAND. IT LOOKS LIKE A RIDGE WILL MOVE INTO THE REGION FRIDAY NIGHT WITH SOUTHERLY WINDS DEVELOPING BY SATURDAY MORNING. SATURDAY...IT LOOKS LIKE A RELATIVELY WARM DAY. SOUTHWESTERLY WINDS WILL DEVELOP AS A LOW PRESSURE SYSTEM MOVES FROM CENTRAL MANITOBA TO WESTERN ONTARIO. THERE MAY BE SOME LIGHT PCPN ACROSS THE NORTHLAND. CONSIDERING THE WARMER SURFACE TEMPERATURES AND TEMPERATURES ALOFT...FORECASTED A POSSIBLE MIXTURE OF RAIN AND SNOW. PLUS...MODEL SOUNDINGS GENERALLY HAD SATURATION ALOFT TO ONLY ABOUT -5 DEGREES CELSIUS OR LESS UNTIL LATER IN THE EVENING WHEN THE COLDER AIR IS USHERED INTO THE NORTHLAND. SO WOULD THINK THE PCPN WOULD LIKELY TURN BACK TO SNOW SATURDAY NIGHT. SUNDAY AND MONDAY...THE BEGINNING OF NEXT WEEK SHOULD START OFF COLD. IT LOOKS LIKE THE POSSIBILITY OF LINGERING SYNOPTIC SNOW ACROSS THE NORTHLAND...AS WELL AS LAKE EFFECT SNOWFALL ALONG PARTS OF THE SOUTH SHORE. THE MODELS INDICATE VERY COLD 850 HPA WILL WRAP INTO THE NORTHLAND...AS LOW AS -16 DEGREES CELSIUS. THIS SHOULD MAKE FOR A SOLID TEMPERATURE DIFFERENCE BETWEEN 850 HPA AND THE LAKE SURFACE TEMPERATURE...WHICH IS AROUND 4 DEGREES CELSIUS. && .POINT TEMPS/POPS... DLH 27 19 29 21 / 30 70 20 20 INL 26 12 26 15 / 30 30 10 20 BRD 32 25 33 24 / 20 60 20 30 HYR 28 20 32 23 / 20 70 30 30 ASX 29 20 33 24 / 20 70 30 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS DULUTH MN
356 AM CST WED DEC 28 2011 .SHORT TERM...THE MAIN FORECAST CONCERN IN THE SHORT TERM IS THE AMOUNT AND LOCATION OF ACCUMULATING SNOWFALL TODAY THROUGH TONIGHT. AT 330 AM...CLOUDS WERE INCREASING AHEAD OF A WEAK SHORTWAVE AND UP[PER LEVEL JET MAX TRAVERSING ACROSS MN. STRONG LOW LEVEL WAA AND THETA-E ADVECTION WAS HELPING TO GENERATE LIGHT SNOW ACROSS WESTERN MN DESPITE INITIALLY DRY LOW LEVEL AIR. THE HRRR RAPID REFRESH WAS DEPICTING THE AREA OF CLOUDS/LIGHT SNOW FAIRLY WELL. THE SHORTWAVE AND 100+ KNOT UPPER LEVEL JET MAX WILL CONTINUE TO PUSH ACROSS THE NORTHLAND TODAY...PUSHING INTO THE WESTERN GREAT LAKES BY THIS AFTERNOON. THE LATEST HRRR ACTUALLY SHOWS THE RETURNS DIMINISHING FOR A TIME THIS EARLY MORNING...BEFORE INCREASING A BIT AGAIN AS THEY REACH NE MN LATER IN THE MORNING. THINK THERE IS A CHANCE FOR ABOUT A HALF INCH OF SNOWFALL IN SPOTS TODAY. COULD SEE A BIT MORE ALONG THE SAWTOOTH MOUNTAINS OF THE NORTH SHORE...AS WINDS COME AROUND TO THE EAST AND SUPPORT LAKE EFFECT SNOW SHOWERS. A STRONGER SYSTEM WILL MOVE IN TONIGHT...AND QUICKLY EXIT THE REGION ON THURSDAY. HAVE SHIFTED THE FOCUS FOR ACCUMULATING SNOWFALL A BIT TO THE SOUTH BASED ON THE LATEST 00Z MODEL RUNS. CURRENT THINKING IS THAT THERE WILL BE A STRIPE OF 1 TO 3 INCHES FROM THE NORTHERN BRAINERD LAKES REGION...THROUGH THE TWIN PORTS AND INTO NW WI. ALSO CANNOT RULE OUT A NARROW STRIPE OF 2 TO 4 INCHES OR POSSIBLY A BIT MORE AS THE SYSTEM DROPS TO THE SOUTHEAST AND LAYS DOWN A SWATH OF ACCUMULATING SNOWFALL. THE NORTH SHORE SHOULD ALSO SEE HIGHER AMOUNTS DUE TO LAKE EFFECT/LAKE ENHANCEMENT. IN TERMS OF SURFACE LOW PRESSURE...THE MODELS ARE FAIRLY SIMILAR...BUT QPF AMOUNTS AND LOCATION DO VARY BETWEEN THE ECMWF/NAM/GFS AND GEM. WILL TAKE A CONSENSUS SOLUTION. MAY NEED TO BUMP UP AMOUNTS IN LATER FORECAST PACKAGES. IN THE GRIDS...CURRENTLY HAVE AMOUNTS SIMILAR TO WHAT IS MENTIONED ABOVE. THINK THE SYSTEM WILL BE FAIRLY EFFICIENT AT RINGING OUT AVAILABLE MOISTURE. THE LOW PRESSURE SYSTEM WILL MOVE OUT OF THE REGION ON THURSDAY...WITH A BIT OF A BREAK BEFORE THE NEXT SYSTEM ARRIVES THURSDAY NIGHT. THE NAM SOLUTION WOULD SUPPORT HIGHER POPS FOR THURSDAY NIGHT...BUT THE ECMWF/GFS KEEP THE ACCUMULATING SNOW GENERALLY WEST AND SOUTH OF THE CWA. .LONG TERM...FRIDAY THROUGH TUESDAY. FRIDAY...THE LONG TERM PERIOD BEGINS WITH LOW CHANCES OF SNOWFALL...MAINLY DUE TO THE GFS SHOWING A TROUGH MOVING THROUGH THE NORTHLAND. IT LOOKS LIKE A RIDGE WILL MOVE INTO THE REGION FRIDAY NIGHT WITH SOUTHERLY WINDS DEVELOPING BY SATURDAY MORNING. SATURDAY...IT LOOKS LIKE A RELATIVELY WARM DAY. SOUTHWESTERLY WINDS WILL DEVELOP AS A LOW PRESSURE SYSTEM MOVES FROM CENTRAL MANITOBA TO WESTERN ONTARIO. THERE MAY BE SOME LIGHT PCPN ACROSS THE NORTHLAND. CONSIDERING THE WARMER SURFACE TEMPERATURES AND TEMPERATURES ALOFT...FORECASTED A POSSIBLE MIXTURE OF RAIN AND SNOW. PLUS...MODEL SOUNDINGS GENERALLY HAD SATURATION ALOFT TO ONLY ABOUT -5 DEGREES CELSIUS OR LESS UNTIL LATER IN THE EVENING WHEN THE COLDER AIR IS USHERED INTO THE NORTHLAND. SO WOULD THINK THE PCPN WOULD LIKELY TURN BACK TO SNOW SATURDAY NIGHT. SUNDAY AND MONDAY...THE BEGINNING OF NEXT WEEK SHOULD START OFF COLD. IT LOOKS LIKE THE POSSIBILITY OF LINGERING SYNOPTIC SNOW ACROSS THE NORTHLAND...AS WELL AS LAKE EFFECT SNOWFALL ALONG PARTS OF THE SOUTH SHORE. THE MODELS INDICATE VERY COLD 850 HPA WILL WRAP INTO THE NORTHLAND...AS LOW AS -16 DEGREES CELSIUS. THIS SHOULD MAKE FOR A SOLID TEMPERATURE DIFFERENCE BETWEEN 850 HPA AND THE LAKE SURFACE TEMPERATURE...WHICH IS AROUND 4 DEGREES CELSIUS. && .AVIATION.../06Z TAF ISSUANCE/ CURRENTLY VFR CONDITIONS WITH 10K FT CIGS MOVING IN FROM THE WEST ASSOCIATED WITH AN UPPER S/W. REGIONAL RADAR IS INDICATING A FEW -SHSN PUSHING INTO NW MN...AND THIS WILL EVENTUALLY MAKE IT TO BRD BEFORE 12Z AND INL JUST AFTER 12Z. AN HOUR OR TWO LATER TO HIB AND DLH BEFORE PASSING THROUGH HYR BY 16Z. SNOW SHOWERS WILL BE VERY SHORT-LIVED WITH THIS FAST MOVING WAVE. CIGS AND VSBYS COULD DROP TO MID/HIGH-END MVFR THIS MORNING...BUT SHOULD LIFT TO LOW- END VFR BY THE AFTERNOON. LIGHT SW WINDS WILL VEER TO SOUTH AND REMAIN LESS THAN 10 KTS OUT OF THE SOUTH THROUGH THIS EVENING. THE NEXT WAVE QUICKLY MOVES IN FROM THE WEST WED EVENING WITH A BETTER CHANCE OF MVFR CIGS/VSBYS BEGINNING JUST BEFORE 06Z. && .POINT TEMPS/POPS... DLH 27 19 29 21 / 30 70 20 20 INL 26 12 26 15 / 30 30 10 20 BRD 32 25 33 24 / 20 60 20 30 HYR 28 20 32 23 / 20 70 30 30 ASX 29 20 33 24 / 20 70 30 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...DAP LONG TERM....GROCHOCINSKI AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS BILLINGS MT
950 AM MST WED DEC 28 2011 .SHORT TERM...VALID FOR TDY AND THU... UPDATE TO MORNING FORECAST TO ISSUE HIGH WIND WARNING ACROSS WESTERN COUNTIES...INCLUDING MUSSELSHELL...YELLOWSTONE...AND EAST CARBON COUNTIES...AND AREAS WEST. WINDS ARE EXPECTED TO PICK UP THIS AFTERNOON ACROSS THE WESTERN ZONES...WITH SUSTAINED WINDS REACHING AROUND 40 MPH AND GUSTS APPROACHING 60 MPH. ALTHOUGH GFS INDICATES AN INVERSION REMAINING IN PLACE ACROSS THE AREA...NAM AND RUC MODELS BOTH INDICATE BREAK DOWN OF INVERSION THIS AFTERNOON...WITH STEEP LAPSE RATES IN THE 1000-850MB LEVEL...RANGING FROM 6 TO 9 C/KM. THIS SHOULD ALLOW FOR STRONG WINDS ALOFT TO MIX DOWN TO THE SFC. WINDS ARE EXPECTED TO DROP OFF THIS EVENING AFTER SUNSET...AS THE INVERSION REDEVELOPS. WINDS WILL PICK UP AGAIN TOMORROW BY LATE MORNING/EARLY AFTERNOON...AND ARE EXPECTED TO BE EVEN STRONGER THAN WINDS EXPERIENCED TODAY. OTHERWISE OVERALL FORECAST APPEARS IN GOOD SHAPE. AAG ...PREVIOUS DISCUSSION... VERY DYNAMIC PATTERN OVER OUR FORECAST AREA THE NEXT COUPLE OF DAYS. MODELS GENERALLY IN GOOD AGREEMENT. MAIN FORECAST ISSUE WILL BE WIND HIGHLIGHTS ACROSS THE PLAINS. EARLY THIS MORNING RADAR TRENDS ALREADY INDICATED SOME LIGHT PRECIP ACROSS THE NORTHERN AND CENTRAL ZONES EXTENDING FROM SUMATRA SOUTH INTO BIG HORN COUNTY. SNOW WAS ALSO INDICATED IN THE HIGH COUNTRY WHERE WEB CAMS SHOWED SNOW AT COOKE CITY. THIS PRECIPITATION CAN BE ATTRIBUTED TO WARM AIR ADVECTION AT 700 MB...AND FAVORABLE JET DYNAMICS WHERE OUR REGION IS UNDER THE INFLUENCE OF LEFT EXIT REGION. THIS IS BATTLING THE STRONG DOWNSLOPE FLOW OFF THE HIGHER TERRAIN WHICH IS WHY LITTLE RADAR RETURNS ARE OCCURRING IN THE FOOTHILLS. THE JET MAX ASSOCIATED WITH THIS FORCING WILL SHIFT QUICKLY EAST BY MIDDAY BRINGING AN END TO MUCH OF THE PRECIP...THOUGH SOME WARM AIR ADVECTION WILL CONTINUE. FAVORABLE PRESSURE GRADIENT WILL CONTINUE FOR THE LIVINGSTON AND NYE AREAS TODAY. THUS WARNING FOR THESE AREAS LOOKS GOOD AS HYBRID GAP FLOW AND MIX DOWN MAY RESULT IN GUSTS TO 75-80 MPH. THE GRADIENT IS SOMEWHAT WEAKER TONIGHT AND NEW DATA SUGGEST QUITE A BIT WEAKER THURSDAY.THEREFORE...WARNING FOR THESE AREAS THROUGH TODAY LOOKS GOOD...BUT MAY NEED TO BE DROPPED EARLY IF MODEL TRENDS CONTINUE TO INDICATE A WEAKENING GRADIENT TONIGHT AND THURSDAY. WILL LET THE DAY SHIFT TAKE ANOTHER LOOK AT THIS. AS FOR HIGH WINDS ON THE PLAINS...THE WARM AIR COMING IN AT THE 700MB LEVEL WILL TEND TO LIMIT POTENTIAL MIX DOWN OF STRONG WINDS TODAY TO AT LEAST SOME EXTENT. HOWEVER...WITH 40 TO 50 KNOT WINDS ONLY 1200-1500 FEET OFF THE GROUND WILL CONTINUE TO RIDE THE HIGH WIND WATCH FOR MUCH OF THE AREA. TONIGHT...WE MAY SEE A STRONG...THOUGH BRIEF...BAROCLINIC BAND SET UP OVER OUR CENTRAL ZONES FROM ROUNDUP TO BROADUS DUE TO WARM AIR ADVECTION TO THE WEST AND COLD ADVECTION COMING IN FROM THE NORTHWEST OVER NORTHEAST MONTANA. CROSS SECTIONS ALSO A PERIOD OF HEAVY SNOW POSSIBLE OVER THE WEST FACING SLOPES IN THE HIGH COUNTRY. OTHERWISE DOWNSLOPE WILL REMAIN A FACTOR FOR MANY AREAS NEAR THE MOUNTAINS AND FOOTHILLS. THURSDAY...140 KT JET MAX NOSES INTO THE REGION RIGHT OVER SOUTHERN MONTANA. ASSOCIATED FORCING WILL PRODUCE A SLIGHT CHANCE OF PRECIP AT THE LOWER ELEVATIONS. HOWEVER THE MAIN THREAT WILL BE WIND ON THURSDAY. STRONG COLD AIR ADVECTION WILL SPREAD INTO THE AREA FROM THE NORTHWEST AT 700 MB. THIS WILL ALLOW A BETTER OPPORTUNITY TO MIX DOWN THE STRONG WINDS ALOFT AS LAPSE RATES WILL BE TWICE WHAT THEY ARE TODAY IN THE LOWER LEVELS. HAVE ADDED THE EASTERN ZONES TO THE HIGH WIND WATCH FOR THURSDAY AS THE STRONGEST WINDS AND STEEPEST PROGGED LAPSE RATES AFFECT THESE ZONES WITH 850 MB WINDS 55 TO 60 KTS. EXPECT WINDS TO QUICKLY SUBSIDE AFTER DARK THURSDAY EVENING. BT .LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE... EXTENDED FORECAST CONTINUES TO LOOK WINDY AND MILD OVERALL WITH MODELS BEING IN GOOD AGREEMENT UNTIL THE MIDDLE OF NEXT WEEK. RIDGE OF HIGH PRESSURE WILL BE OVER THE STATE FRIDAY ALONG WITH A STRONG LEE-SIDE TROUGH. THIS WILL BRING VERY WINDY CONDITIONS ACROSS THE ENTIRE FORECAST AREA WITH MILD TEMPERATURES. MODELS BRING A STRONG TROUGH AND COLD FRONT ACROSS THE FORECAST AREA SATURDAY BRINGING A CHANCE OF RAIN AND SNOW SHOWERS TO THE PLAINS WITH VERY WINDY CONDITIONS POSSIBLE. WINDS WILL SUBSIDE ON SUNDAY WITH TEMPERATURES RETURNING BACK TO NORMAL LEVELS FOR THIS TIME OF YEAR. RIDGING THEN BEGINS TO BUILD BACK ONCE AGAIN SUNDAY NIGHT INTO MONDAY BRINGING CONTINUED DRY CONDITIONS AND A RETURN TO ABOVE NORMAL TEMPERATURES. IN GENERAL FOR MONDAY INTO THE MIDDLE OF NEXT WEEK...A FAST FLOW ALOFT WILL CONTINUE WITH ALTERNATING RIDGING AND TROUGHING AS SEVERAL SYSTEMS MOVE OVER THE FORECAST AREA. LEE-SIDE TROUGHING WILL BE IN PLACE AT TIMES AS WELL RESULTING IN PERIODS OF STRONG GUSTY WINDS. HOOLEY && .AVIATION... STRONG AND GUSTY WINDS WILL CONTINUE FROM BIG TIMBER TO KLVM AND THE ADJACENT FOOTHILLS TODAY. GUSTS OVER 65 KNOTS WILL BE LIKELY ACROSS THESE AREAS. STRONG AND GUSTY WINDS ARE ALSO EXPECTED TO SPREAD EASTWARD TO KBIL THIS AFTERNOON WITH GUSTS AROUND 55 KTS. SNOW WILL IMPACT AREA MOUNTAINS TODAY AND TONIGHT. MOUNTAINS OBSCURATIONS CAN BE EXPECTED. VFR CONDITIONS CAN BE EXPECTED OVER THE PLAINS. RICHMOND && .PRELIMINARY POINT TEMP/POPS... TDY THU FRI SAT SUN MON TUE ------------------------------------------------------- BIL 053 036/053 030/049 032/043 023/037 023/045 029/044 3/W 42/W 22/W 21/N 10/B 00/B 00/B LVM 050 040/049 033/049 034/039 019/036 022/044 032/043 2/J 44/W 23/W 21/N 10/B 00/B 00/B HDN 058 032/057 026/053 026/044 019/037 018/047 025/046 3/W 43/W 21/B 21/N 00/B 00/U 00/B MLS 054 032/053 027/049 029/041 020/036 018/044 025/045 4/W 23/W 11/B 11/N 00/B 00/U 00/B 4BQ 054 031/054 026/050 027/043 020/038 018/046 024/047 3/W 23/W 21/B 21/N 10/B 00/U 00/U BHK 050 029/049 025/046 031/038 017/032 016/041 025/042 2/W 23/W 11/B 11/N 10/B 00/U 00/U SHR 048 027/048 024/046 030/041 016/035 015/042 023/043 2/W 23/W 21/B 22/J 10/B 00/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...HIGH WIND WARNING IN EFFECT UNTIL 8 PM MST THIS EVENING FOR ZONES 28-29-34-35-39-41-42. HIGH WIND WATCH IN EFFECT FROM THURSDAY MORNING THROUGH THURSDAY AFTERNOON FOR ZONES 28>39-41-42-57-58. HIGH WIND WARNING IN EFFECT UNTIL 11 AM MST FRIDAY FOR ZONES 65-66. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
518 PM CST THU DEC 29 2011 .UPDATE... .AVIATION... VFR IS EXPECTED ALL AREAS TONIGHT AND FRIDAY. SCATTERED SHOWERS LOWERING CIGS TO OVC040 ARE EXPECTED TO EXIT THE FORECAST AREA BY 06Z THIS EVENING. WIND GUSTS TO 35 MPH OR HIGHER SHOULD BECOME LESS FREQUENT THIS EVENING. THEREAFTER...SCATTERED TO BROKEN HIGH CLOUDINESS. && .PREV DISCUSSION... /ISSUED 326 PM CST THU DEC 29 2011/ UPDATE... AVIATION... MID AND HIGH LEVEL CLOUDS WILL CONTINUE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON...WITH SKIES CLEARING TONIGHT. CEILINGS MAY GET AS LOW AS 5000 FT AGL...ALONG WITH SCT RAIN SHOWERS AND A FEW THUNDERSTORMS LATE THIS AFTERNOON AND EARLY THIS EVENING. OVERALL VFR EXPECTED TO PREVAIL...WITH GUSTY WEST WINDS TO 40 KTS WEST OF HIGHWAY 183 FROM LATE AFTERNOON THROUGH THE EVENING. LOCAL GUSTS TO 50 KTS ARE POSSIBLE INVOF SHOWERS/STORMS. PREV DISCUSSION... /ISSUED 321 PM CST THU DEC 29 2011/ DISCUSSION... SHORT TERM... WIND ADVISORY CONDITIONS ARE SPREADING THROUGH ALL OF THE WRN NEB PANHANDLE THIS AFTERNOON. THERE IS THE POTENTIAL FOR STRONG WINDS TO SPREAD THROUGH ALL OF THE PANHANDLE UNTIL 23Z. THEREAFTER THE LOSS OF DAYTIME HEATING SHOULD CAUSE A DROP IN GUSTS. 30 MPH SUSTAINED CONDITIONS MIGHT CONTINUE THIS EVENING AS LOW PRESSURE TRACKS THROUGH THE MISSOURI BASIN. THE RUC SHOWS A PRONOUNCED TROP FOLD ON THE PV15 SURFACE WHICH SHOULD MOVE THRU THE FCST AREA THIS EVENING. THUS THE WIND ADZY WILL CONTINUE ACROSS GARDEN AND DEUEL COUNTIES WITH A POSSIBLE NORTH AND EAST EXPANSION AS CONDITIONS WARRANT. SCATTERED SHOWERS ISOLATED THUNDERSTORMS ARE EXPECTED TO CONTINUE TRACKING THRU NRN NEB THIS EVENING. THE STRONG WEST WINDS ARE BEING USHERED IN AHEAD OF A PACIFIC COLD FRONT WORKING THRU NERN WY. THE FRONT SHOULD COOL TEMPS OFF SOMEWHAT FOR FRIDAY WITH HIGHS ABOUT 10F COOLER THAN TODAY. ANOTHER STRONG COLD FRONT IS EXPECTED TO MOVE THROUGH SATURDAY MORNING...EARLY AFTERNOON. THIS FRONT IN COMBINATION WITH DEEPENING LOW PRESSURE ACROSS THE UPPER MIDWEST AND VERY STRONG PACIFIC HIGH PRESSURE SHOULD PRODUCE WIND ADVISORY CONDITIONS ACROSS MOST AND POSSIBLY ALL OF THE FCST AREA. A BLEND OF MODEL DATA AND GUIDANCE WAS USED FOR THE FCST WHICH PRODUCED HIGH END WIND ADVISORY CONDITIONS ACROSS SWRN NEB. AMPLE MOISTURE WILL BE PRESENT ALONG AND BEHIND THE FRONT SATURDAY FOR SCATTERED RAIN AND SNOW SHOWERS...MAINLY ACROSS THE NORTH. ANOTHER STRONG TROP FOLD WILL SWEEP THE FCST AREA IN CONCERT WITH THE FRONTAL PASSAGE. THE GFS WAS OVERPOWERING WITH THE WIND STRENGTH AND COLD AIR PRODUCING ALL SNOW WHILE THE NAM SHOWED A MIX WITH WEAKER WINDS. THE WARMER NAM WAS PREFERRED. PACIFIC HIGH PRESSURE WILL BUILD ACROSS THE FCST AREA SUNDAY PRODUCING HIGHS IN THE UPPER 30S TO AROUND 40 WITH NEARLY CLEAR SKIES. LONG TERM... A RIDGE OF HIGH PRESSURE ALOFT WILL BE AMPLIFYING MONDAY ACROSS THE ROCKIES...WHILE A TROUGH OF LOW PRESSURE CONTINUES IT/S EASTWARD PROGRESSION INTO THE NORTHEAST STATES. OUR AREA WILL BE IN BETWEEN THESE TWO FEATURES...WITH A BROAD NORTHWEST FLOW ALOFT. 850 MB TEMPERATURES WILL BEGIN TO RECOVER MONDAY...AND CONTINUE TO WARM THOUGH THURSDAY. IN FACT BY THURSDAY MODELS ARE SUGGESTING +15C OVER THE AREA...WHICH WOULD PUT HIGH TEMPERATURES INTO POSSIBLE RECORD TERRITORY. SO AFTER A COOL START MONDAY...HIGHS MID 30S TO MID 40S...TUESDAY THROUGH THURSDAY LOOKING VERY MILD. COULD BE PUSHING 60 DEGREES OR WARMER AGAIN BY THURSDAY. AVIATION... MID AND HIGH LEVEL CLOUDS WILL CONTINUE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON...WITH SKIES CLEARING TONIGHT. CEILINGS MAY GET AS LOW AS 5000 FT AGL...ALONG WITH A FEW RAIN SHOWERS...ACROSS NORTH CENTRAL NEBRASKA LATE THIS AFTERNOON AND EARLY THIS EVENING. VFR EXPECTED TO PREVAIL...WITH GUSTY WEST WINDS TO 30 KTS WEST OF HIGHWAY 83 FROM LATE AFTERNOON THROUGH THE EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 11 PM MST THIS EVENING FOR NEZ022-056. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
700 AM EST WED DEC 28 2011 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION TODAY AND LINGER THROUGH FRIDAY. A COLD FRONT WILL PUSH THROUGH THE AREA FRIDAY NIGHT. ANOTHER AREA OF HIGH PRESSURE WILL BUILD IN THIS WEEKEND. A STRONG COLD FRONT WILL PUSH THROUGH SUNDAY NIGHT OR EARLY MONDAY OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 7 AM WED...CURRENT H20 VAPOR ANALYSIS INDICATING H7 TROUGH AXIS SWINGING THROUGH E NC AND COASTAL WATERS. CAA CONTINUES TO KEEP WINDS IN THE 10 TO 15 KT RANGE AT THE SFC EARLY THIS MORNING. RUC ANALYSIS INDICATES LARGEST PRES RISES CONTINUING THROUGH MID MORNING TODAY...WHICH IN CONJUNCTION WITH EFFICIENT UNIDIRECTIONAL SHEAR IN THE BL WILL BRING DOWN HIGHER WINDS ALOFT IN THE FORM OF GUSTS IN THE 20 TO 25 KT RANGE AT THE SFC. GRADIENT WILL REMAIN STRONGEST ACROSS THE OBX AND WITH GOOD MIXING...WILL LEAVE THE CURRENT WIND ADVISORY IN EFFECT...THOUGH CRITERIA WILL BE MARGINAL. GRADIENT RELAXES BY THIS AFTERNOON AND WINDS WILL DIMINISH IN RESPONSE. FOR TEMP FCST...USED MODEL BLEND OF THE BIAS CORRECTED GFS/SREF GRIDS AND 1000-850 MB THICKNESSES TO YIELD HIGHS GENERALLY IN THE LOWER 50S ACROSS E NC. IT WILL FEEL QUITE A BIT COOLER DUE TO THE BRISK WESTERLY WINDS HOWEVER. SKIES WILL BE MOSTLY SUNNY AS DEEP LAYER DRYING CONTINUES THROUGH THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... AS OF 3 AM WED...GUSTY WINDS OF TODAY WILL DIMINISH QUITE RAPIDLY TOWARDS SUNSET THIS EVENING AS PRES GRADIENT WEAKENS AND DRY HIGH PRES BEGINS BUILDING IN FROM THE WEST. TD VALS WILL PLUMMET THROUGH THE 20S AND WITH CLEAR SKIES AND CALM WINDS OVERNIGHT... MIN TEMPS WILL FOLLOW SUIT AND SETTLE INTO THE 20S FOR AREAS AWAY FROM THE IMMEDIATE COAST. NW WINDS WILL CONTINUE FOR THE OBX WITH LOWS HERE IN THE 30S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 300 AM WED...NO SIGNIFICANT CHANGES TO PREVIOUS FCST DURING PERIOD. MODELS IN DECENT AGREEMENT WITH NEAR ZONAL FLOW PATTERN INTO EARLY NEXT WEEK...WITH STRONGEST NORTHERN STREAM SHRT WV MOVING THROUGH SAT. GULFMEX WILL BE CUTOFF SO JUST A DRY FRONTAL PASSAGE EXPECTED AT SFC WITH THIS SYSTEM. DID ADJUST TEMPS THU-FRI BASED ON LATEST MOS GDNC BLEND. MODELS CONTINUE TO INDICATE UPR TROFFING OVER ERN US MON INTO TUE. 00Z ECMWF MORE PROGRESSIVE THAN PREVIOUS RUNS WITH TROF...WITH SFC LOW DEVELOPMENT FARTHER OFFSHORE MIDWEEK...BUT LIKELY OVERDONE WITH DEPTH OF TROF PER EXTENDED PROG DISCUSSIONS. MODELS DO CONTINUE TO INDICATE ENOUGH DYNAMICS WITH UPR SYSTEM TO KEEP 20 POPS FOR SUN NIGHT AND MONDAY. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /TODAY AND TONIGHT/... AS OF 7 AM WED...PRES RISES WILL BE GREATEST THROUGH THE MORNING AND WITH GOOD MIXING TODAY...WILL SEE WINDS GUSTING INTO THE 20 TO 25 KT RANGE FOR ALL TERMINALS. SKIES WILL BE SUNNY AS DRY HIGH PRES BUILDS IN. WINDS DIMINISH VERY QUICKLY TOWARDS SUNSET AS HIGH BUILDS IN...GRADIENT RELAXES AND CAA SUBSIDES. DO NOT EXPECT FOG OR BR AS BNDRY LAYER WILL BE QUITE DRY WITH TD VALS IN THE LOW TO MID 20S OVERNIGHT...THOUGH TYPICAL LOCALES SUCH AS KPGV WILL HAVE TO BE MONITORED FOR BR DEVELOPMENT. LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM WED...VFR THROUGH THE PERIOD. ISOLATED SHOWERS POSSIBLE SUNDAY NIGHT WITH A STONGER UPR LEVEL TROF. && .MARINE... SHORT TERM /THROUGH TONIGHT/ AS OF 7 AM WED...CURRENT SFC OBS INDICATING MARGINAL GALE CONDITIONS OCCURING OFF NC COAST. FRYING PAN BUOY GUSTING BETWEEN 35 AND 40 KT THROGUH THIS MORNING...AND A SHIP 30 MI SE CAPE HATTERAS REPORTING SUSTAINED WINDS OF 30 KT. NEAR TERM GUIDANCE INDICATES GREATEST ISALLOBARIC PRES RISES OCCURRING RIGHT NOW AS TROUGH AXIS IS SWINGING THROUGH THE COASTAL WATERS. THIS IS IN LINE WITH HRRR WINDS GUSTS APPROACHING GALE FORCE THROUGH ABOUT THIS TIME. WINDS WILL OCCASIONALLY GUST TO GALE FORCE OVER EASTERN PORTIONS OF PAMLICO SOUND AS WELL THROUGH MID MORNING. 700 MB TROUGH AXIS WILL EXIT THE NC COASTAL WATERS THIS MORNING...AND WITH DEPARTING THOUGH DEEPENING LOW ACROSS NEW ENGLAND...WINDS WILL BEGIN TO ABATE. CAA HOWEVER WILL CONTINUE TO PRODUCE SCA WIND GUSTS THROUGH MUCH OF TODAY...AND WILL HAVE TO REPLACE GALES WITH SCA AFTER THEIR SCHEDULED EXPIRATION TIMES OF 15Z. SEAS WILL ALSO REMAIN ABOVE 6 FT FOR THE REMAINDER OF TODAY...HIGHEST THROUGH THIS MORNING. LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM WED...BRIEF PERIOD OF LIGHTER WINDS AND SEAS THU MORNING...THEN GRADIENT BETWEEN LOW PRESSURE MOVING ACROSS N OF AREA AND HIGH PRESSURE TO S WILL PRODUCE INCREASING W TO SW WINDS THU NIGHT INTO FRI NIGHT...WITH MARGINAL SCA CONDITIONS PSBL FOR OUTER PORTIONS OF WATERS. WINDS BECOMING NRLY LATE SAT FOLLOWING DRY FRONTAL PASSAGE...WITH SPEEDS DECREASING SAT NIGHT WITH HIGH PRES BUILDING IN FROM W. WINDS WILL VEER QUICKLY BACK TO SW SUN AS HIGH PRES MOVES OFFSHORE. BLEND OF WW3...LOCAL SWAN AND PREVIOUS FCST USED FOR SEAS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NCZ103-104. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR AMZ130- 135. GALE WARNING UNTIL 10 AM EST THIS MORNING FOR AMZ150-152-154- 156-158. && $$ SYNOPSIS...TL NEAR TERM...TL SHORT TERM...TL LONG TERM...JBM AVIATION...TL/JBM MARINE...TL/JBM
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
337 AM EST WED DEC 28 2011 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION TODAY AND LINGER THROUGH FRIDAY. A COLD FRONT WILL PUSH THROUGH THE AREA FRIDAY NIGHT. ANOTHER AREA OF HIGH PRESSURE WILL BUILD IN THIS WEEKEND. A STRONG COLD FRONT WILL PUSH THROUGH SUNDAY NIGHT OR EARLY MONDAY OF NEXT WEEK. && .NEAR TERM /TODAY/... AS OF 3 AM WED...CURRENT H20 VAPOR ANALYSIS INDICATING H7 TROUGH AXIS SWINGING THROUGH CENTRAL NC ATTM. MODEST CAA CONTINUES TO KEEP WINDS IN THE 10 TO 15 KT RANGE AT THE SFC EARLY THIS MORNING. RUC ANALYSIS INDICATES LARGEST PRES RISES CONTINUING THROUGH LATE MORNING TODAY...WHICH IN CONJUNCTION WITH EFFICIENT UNIDIRECTIONAL SHEAR IN THE BL WILL BRING DOWN WINDS ALOFT IN THE FORM OF GUSTS IN THE 20 TO 25 KT RANGE AT THE SFC. GRADIENT WILL REMAIN STRONGEST ACROSS THE OBX AND WITH GOOD MIXING...WILL LEAVE THE CURRENT WIND ADVISORY IN EFFECT...THOUGH CRITERIA WILL BE MARGINAL. GRADIENT RELAXES THIS AFTERNOON AND WINDS WILL DIMINISH IN RESPONSE. FOR TEMP FCST...USED MODEL BLEND OF THE BIAS CORRECTED GFS/SREF GRIDS AND 1000-850 MB THICKNESSES TO YIELD HIGHS GENERALLY IN THE LOWER 50S ACROSS E NC. IT WILL FEEL QUITE A BIT COOLER DUE TO THE BRISK WESTERLY WINDS HOWEVER. SKIES WILL BE MOSTLY SUNNY AS DEEP LAYER DRYING CONTINUES THROUGH THE DAY. && .SHORT TERM /TONIGHT/... AS OF 3 AM WED...GUSTY WINDS OF TODAY WILL DIMINISH QUITE RAPIDLY TOWARDS SUNSET THIS EVENING AS PRES GRADIENT WEAKENS AND DRY HIGH PRES BEGINS BUILDING IN FROM THE WEST. TD VALS WILL PLUMMET THROUGH THE 20S AND WITH CLEAR SKIES AND CALM WINDS OVERNIGHT... MIN TEMPS WILL FOLLOW SUIT AND SETTLE INTO THE 20S FOR AREAS AWAY FROM THE IMMEDIATE COAST. NW WINDS WILL CONTINUE FOR THE OBX WITH LOWS HERE IN THE 30S. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 300 AM WED...NO SIGNIFICANT CHANGES TO PREVIOUS FCST DURING PERIOD. MODELS IN DECENT AGREEMENT WITH NEAR ZONAL FLOW PATTERN INTO EARLY NEXT WEEK...WITH STRONGEST NORTHERN STREAM SHRT WV MOVING THROUGH SAT. GULFMEX WILL BE CUTOFF SO JUST A DRY FRONTAL PASSAGE EXPECTED AT SFC WITH THIS SYSTEM. DID ADJUST TEMPS THU-FRI BASED ON LATEST MOS GDNC BLEND. MODELS CONTINUE TO INDICATE UPR TROFFING OVER ERN US MON INTO TUE. 00Z ECMWF MORE PROGRESSIVE THAN PREVIOUS RUNS WITH TROF...WITH SFC LOW DEVELOPMENT FARTHER OFFSHORE MIDWEEK...BUT LIKELY OVERDONE WITH DEPTH OF TROF PER EXTENDED PROG DISCUSSIONS. MODELS DO CONTINUE TO INDICATE ENOUGH DYNAMICS WITH UPR SYSTEM TO KEEP 20 POPS FOR SUN NIGHT AND MONDAY. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM /TODAY AND TONIGHT/... AS OF 3 AM WED...WEST WINDS BEHIND SFC FRONT WILL REMAIN QUITE STRONG THROUGH EARLY THIS MORNING AS TIGHT GRAD REMAINS AND STRONG CAA UNDERWAY. PRES RISES WILL BE GREATEST THROUGH THE MORNING AND WITH GOOD MIXING TODAY...WILL SEE WINDS GUSTING INTO THE 20 TO 25 KT RANGE FOR ALL TERMINALS. SKIES WILL BE SUNNY AS DRY HIGH PRES BUILDS IN. WINDS DIMINISH DRASTICALLY TOWARDS SUNSET AS THE GRADIENT RELAXES AND CAA COMES TO A HALT. DO NOT EXPECT FOG OR BR AS BNDRY LAYER WILL BE QUITE DRY WITH TD VALS IN THE LOW TO MID 20S OVERNIGHT. LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM WED...VFR THROUGH THE PERIOD. ISOLATED SHOWERS POSSIBLE SUNDAY NIGHT WITH A STONGER UPR LEVEL TROF. && .MARINE... SHORT TERM /THROUGH TONIGHT/ AS OF 3 AM WED...CURRENT SFC OBS INDICATING MARGINAL GALE CONDITIONS OCCURING OFF NC COAST. FRYING PAN BUOY GUSTING BETWEEN 35 AND 40 KT EARLY THIS MORNING...AND EARLIER SHIP OB 35 SE CAPE LOOKOUT REPORTED SUSTAINED WINDS OF 35 KT. NEAR TERM GUIDANCE INDICATES GREATEST ISALLOBARIC PRES RISES OCCURRING NEAR 12 Z THIS MORNING. THIS IS IN LINE WITH HRRR WINDS GUSTS APPROACHING GALE FORCE THROUGH ABOUT THIS TIME. 700 MB TROUGH AXIS WILL EXIT THE NC COASTAL WATERS AFTER 12Z...AND WITH DEPARTING THOUGH DEEPENING LOW ACROSS NEW ENGLAND...WINDS WILL BEGIN TO ABATE. CAA HOWEVER WILL CONTINUE TO PRODUCE SCA WIND GUSTS THROUGH MUCH OF TODAY...AND WILL HAVE TO REPLACE GALES WITH SCA AFTER THEIR SCHEDULED EXPIRATION TIMES. SEAS WILL ALSO REMAIN ABOVE 6 FT FOR THE REMAINDER OF TODAY...HIGHEST EARLY THIS MORNING. LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM WED...BRIEF PERIOD OF LIGHTER WINDS AND SEAS THU MORNING...THEN GRADIENT BETWEEN LOW PRESSURE MOVING ACROSS N OF AREA AND HIGH PRESSURE TO S WILL PRODUCE INCREASING W TO SW WINDS THU NIGHT INTO FRI NIGHT...WITH MARGINAL SCA CONDITIONS PSBL FOR OUTER PORTIONS OF WATERS. WINDS BECOMING NRLY LATE SAT FOLLOWING DRY FRONTAL PASSAGE...WITH SPEEDS DECREASING SAT NIGHT WITH HIGH PRES BUILDING IN FROM W. WINDS WILL VEER QUICKLY BACK TO SW SUN AS HIGH PRES MOVES OFFSHORE. BLEND OF WW3...LOCAL SWAN AND PREVIOUS FCST USED FOR SEAS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...WIND ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NCZ103-104. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ130- 135. GALE WARNING UNTIL 10 AM EST THIS MORNING FOR AMZ150-152-154. GALE WARNING UNTIL 7 AM EST THIS MORNING FOR AMZ156-158. && $$ SYNOPSIS...TL NEAR TERM...TL SHORT TERM...TL LONG TERM...JBM AVIATION...TL/JBM MARINE...TL/JBM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
708 AM EST WED DEC 28 2011 .SYNOPSIS... BLUSTERY WEST WINDS WILL CREATE SOME LAKE EFFECT SNOW AND FLURRIES TODAY...BUT THE SNOW SHOWERS WILL TAPER OFF THROUGH THE DAY. WEAK HIGH PRESSURE TONIGHT WILL BE PUSHED TO THE SOUTH AS A COUPLE OF ALBERTA CLIPPERS MOVE ACROSS THE GREAT LAKES THURSDAY NIGHT AND FRIDAY...AND COULD PRODUCE A FEW INCHES OF SNOW IN THE NORTH AND WEST. FAIR WEATHER SHOULD FOLLOW FOR SATURDAY. && .NEAR TERM /UNTIL NOON TODAY/... TIGHT P-GRADIENT AROUND THE DEPARTED STORM WILL CONTINUE TO CREATE GUSTY WINDS OVER THE STATE. BUFKIT MOMENTUM TRANSFER VALUES FROM NAM AND RUC SHOW GUSTS WILL PROBABLY TOP OUT IN THE M/U30KT RANGE...BUT RUN THROUGH MUCH OF THE DAY. LAST VESTIGE OF THE UPPER LOW APPEARS TO HAVE JUST PASSED KELZ AND KUNV. RADAR SHOWS SNOW IN VERY LONG BUT ALSO VERY THIN/NARROW BANDS. VERY FEW IFR OBS TO BE FOUND. THE GUSTY WINDS WILL BE CREATING A GREAT DEAL OF SHEAR IN THE CLOUD LAYER. THIS WILL MEAN THAT THE BANDS WILL BE TRANSITORY. SINCE THEY ARE SO NARROW...IT WILL BE DIFFICULT FOR EVEN LIGHT ACCUMS TO OCCUR. THE INVERSION LOWERS A BIT THIS MORNING AS THE HIGH OVER THE CENTRAL STATES SLIDES EASTWARD. WILL CONTINUE WITH THE CURR ADVY IN THE NW 3 COS...CLOSE TO THE LAKE. BUT MOST PLACES WILL STRUGGLE TO GET EVEN ANOTHER INCH...ESP SINCE THE SNOW WILL BE BLOWING AROUND AND MAKE MEASURING DIFFICULT. CLOUDS WILL START TO BREAK UP IN THE MORNING IN THE DOWNSLOPE AREAS...BUT IT WILL BE TOUGH TO CLEAR UP SKIES OVER THE W. && .SHORT TERM /NOON TODAY THROUGH 6 PM THURSDAY/... LAKE EFFECT SNOW WANES IN WESTERN ZONES AS INVERSION HEIGHTS COME DOWN LATER THIS MORNING AND EARLY THIS AFTN. ANY ACCUMS AFTER NOON WILL BE NEGLIGIBLE. GUSTY WINDS WILL CONTINUE AS PRESSURE RISES 8-10 MB BEFORE SUNSET. TEMPS WILL BE FLAT OR EVEN DROP THROUGH THE DAY AS THE 8H TEMPS DROP 7-8C THROUGH THE DAY. THE SFC RIDGE SLIDES OVERHEAD THROUGH THE NIGHT...GRADUALLY SLACKENING THE WINDS THIS EVENING AND EARLY TONIGHT. MINS WILL BE IN THE TEENS AND L20S. THESE TEMPS ARE JUST ABOUT AS COLD AS WE HAVE BEEN THIS WINTER...WITH ONLY THE 10TH-12TH OF THE MONTH AS COLD OR COLDER. SUNSHINE EARLY IN THE DAY AND RETURN FLOW WILL ALLOW TEMPS TO RISE BACK TO OR EVEN SLIGHTLY ABOVE NORMALS. AN APPROACHING NRN STREAM WAVE WILL SPREAD HIGH/MID CLOUDS INTO THE NRN TIER THROUGH THE DAY ON THURS...BUT ANY LIGHT SNOW SHOULD NOT ARRIVE UNTIL LATE IN THE DAY IN THE NW. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A QUICK MOVING CLIPPER SYSTEM WILL SHOOT THROUGH THE GREAT LAKES AFFECTING MAINLY MY NORTHERN ZONES THURSDAY NIGHT. A SECONDARY SHOT OF MOISTURE QUICKLY MOVES ALONG THE INTERSTATE 80 CORRIDOR DURING THE DAY FRIDAY INTO SATURDAY MORNING. THESE FEATURES ARE SIMILARLY HANDLED BY VARYING MODEL GUIDANCE WITH JUST A FEW DIFFERENCES IN TIMING AND INTENSITY. MODELS ALSO AGREE ON ANOTHER SHOT OF MOISTURE MOVING THROUGH LATE SUNDAY INTO MONDAY AHEAD OF AN ARCTIC AIRMASS TO MOVE IN FOR THE MIDDLE OF NEXT WEEK. AS WE MOVE INTO THAT TIMEFRAME...SIGNIFICANT MODEL DIFFERENCES EXIST. THE ECMWF BRINGS A SLOW MOVING STORM SYSTEM NORTHWEST FROM THE ATLANTIC COAST WELL INTO PENNSYLVANIA BY THE MIDDLE OF NEXT WEEK. HOWEVER...THE GFS HAS THE REGION IN COLD NORTHWEST FLOW WITH SOME OF THE COLDEST AIR OF THE SEASON CLIPPING NORTHEAST PA WITH ONLY RESULTANT LAKE EFFECT BRINGING SNOW TO THE AREA. LACK OF SNOW BEGETS LACK OF SNOW. HUGE STORMS IN THE 5-7 DAY RANGE FIZZLING BEGETS HUGE STORMS IN THE 5-7 DAY RANGE FIZZLING. IT IS THE TREND OF THIS WINTER SO WILL HOLD OFF ON ANY BELLS...OR WHISTLES...AT THIS POINT. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... WINDS NOW ARE NW. GUSTY WINDS WILL PREVAIL AS THE COLD AIR ADVECTS THROUGH THE REGION. EXPECT LAKE ENHANCED SNOW SHOWERS CAUSING IFR CONDITIONS AT BFD AND JST UNTIL LATE MORNING OR EARLY AFTERNOON. MVFR CIGS AT UNV AND AOO AT TIMES THIS MORNING...AS THE UPPER LVL TROUGH MOVES ACROSS. EXPECT VFR CONDITIONS FURTHER EAST. GENERALLY VFR CONDS EXPECTED ON THU...ALTHOUGH SOME -SHSN ARE POSSIBLE LATE ACROSS NW PA. A SLIGHTLY BETTER CHC OF SNOW OR RAIN SHOWERS FRI...AS A CLIPPER SYSTEM MOVES EASTWARD...JUST NORTH OF PA. VFR CONDS RETURN FOR NEW YEARS WEEKEND...AS HIGH PRESSURE BUILDS IN. PERHAPS A SHOWER LATE SUNDAY WITH THE NEXT COLD FRONT. OUTLOOK... THU...GENERALLY VFR. FRI...MVFR/IFR MAINLY WESTERN AREAS WITH RAIN/SNOW SHOWERS. SAT-SUN...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR PAZ004-005- 010. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...TYBURSKI AVIATION...CERU/MARTIN/EVANEGO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
639 AM EST WED DEC 28 2011 .SYNOPSIS... BLUSTERY WEST WINDS WILL CREATE SOME LAKE EFFECT SNOW AND FLURRIES TODAY...BUT THE SNOW SHOWERS WILL TAPER OFF THROUGH THE DAY. WEAK HIGH PRESSURE TONIGHT WILL BE PUSHED TO THE SOUTH AS A COUPLE OF ALBERTA CLIPPERS MOVE ACROSS THE GREAT LAKES THURSDAY NIGHT AND FRIDAY...AND COULD PRODUCE A FEW INCHES OF SNOW IN THE NORTH AND WEST. FAIR WEATHER SHOULD FOLLOW FOR SATURDAY. && .NEAR TERM /UNTIL NOON TODAY/... TIGHT P-GRADIENT AROUND THE DEPARTED STORM WILL CONTINUE TO CREATE GUSTY WINDS OVER THE STATE. BUFKIT MOMENTUM TRANSFER VALUES FROM NAM AND RUC SHOW GUSTS WILL PROBABLY TOP OUT IN THE M/U30KT RANGE...BUT RUN THROUGH MUCH OF THE DAY. LAST VESTIGE OF THE UPPER LOW APPEARS TO HAVE JUST PASSED KELZ AND KUNV. RADAR SHOWS SNOW IN VERY LONG BUT ALSO VERY THIN/NARROW BANDS. VERY FEW IFR OBS TO BE FOUND. THE GUSTY WINDS WILL BE CREATING A GREAT DEAL OF SHEAR IN THE CLOUD LAYER. THIS WILL MEAN THAT THE BANDS WILL BE TRANSITORY. SINCE THEY ARE SO NARROW...IT WILL BE DIFFICULT FOR EVEN LIGHT ACCUMS TO OCCUR. THE INVERSION LOWERS A BIT THIS MORNING AS THE HIGH OVER THE CENTRAL STATES SLIDES EASTWARD. WILL CONTINUE WITH THE CURR ADVY IN THE NW 3 COS...CLOSE TO THE LAKE. BUT MOST PLACES WILL STRUGGLE TO GET EVEN ANOTHER INCH...ESP SINCE THE SNOW WILL BE BLOWING AROUND AND MAKE MEASURING DIFFICULT. CLOUDS WILL START TO BREAK UP IN THE MORNING IN THE DOWNSLOPE AREAS...BUT IT WILL BE TOUGH TO CLEAR UP SKIES OVER THE W. && .SHORT TERM /NOON TODAY THROUGH 6 PM THURSDAY/... LAKE EFFECT SNOW WANES IN WESTERN ZONES AS INVERSION HEIGHTS COME DOWN LATER THIS MORNING AND EARLY THIS AFTN. ANY ACCUMS AFTER NOON WILL BE NEGLIGIBLE. GUSTY WINDS WILL CONTINUE AS PRESSURE RISES 8-10 MB BEFORE SUNSET. TEMPS WILL BE FLAT OR EVEN DROP THROUGH THE DAY AS THE 8H TEMPS DROP 7-8C THROUGH THE DAY. THE SFC RIDGE SLIDES OVERHEAD THROUGH THE NIGHT...GRADUALLY SLACKENING THE WINDS THIS EVENING AND EARLY TONIGHT. MINS WILL BE IN THE TEENS AND L20S. THESE TEMPS ARE JUST ABOUT AS COLD AS WE HAVE BEEN THIS WINTER...WITH ONLY THE 10TH-12TH OF THE MONTH AS COLD OR COLDER. SUNSHINE EARLY IN THE DAY AND RETURN FLOW WILL ALLOW TEMPS TO RISE BACK TO OR EVEN SLIGHTLY ABOVE NORMALS. AN APPROACHING NRN STREAM WAVE WILL SPREAD HIGH/MID CLOUDS INTO THE NRN TIER THROUGH THE DAY ON THURS...BUT ANY LIGHT SNOW SHOULD NOT ARRIVE UNTIL LATE IN THE DAY IN THE NW. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A QUICK MOVING CLIPPER SYSTEM WILL SHOOT THROUGH THE GREAT LAKES AFFECTING MAINLY MY NORTHERN ZONES THURSDAY NIGHT. A SECONDARY SHOT OF MOISTURE QUICKLY MOVES ALONG THE INTERSTATE 80 CORRIDOR DURING THE DAY FRIDAY INTO SATURDAY MORNING. THESE FEATURES ARE SIMILARLY HANDLED BY VARYING MODEL GUIDANCE WITH JUST A FEW DIFFERENCES IN TIMING AND INTENSITY. MODELS ALSO AGREE ON ANOTHER SHOT OF MOISTURE MOVING THROUGH LATE SUNDAY INTO MONDAY AHEAD OF AN ARCTIC AIRMASS TO MOVE IN FOR THE MIDDLE OF NEXT WEEK. AS WE MOVE INTO THAT TIMEFRAME...SIGNIFICANT MODEL DIFFERENCES EXIST. THE ECMWF BRINGS A SLOW MOVING STORM SYSTEM NORTHWEST FROM THE ATLANTIC COAST WELL INTO PENNSYLVANIA BY THE MIDDLE OF NEXT WEEK. HOWEVER...THE GFS HAS THE REGION IN COLD NORTHWEST FLOW WITH SOME OF THE COLDEST AIR OF THE SEASON CLIPPING NORTHEAST PA WITH ONLY RESULTANT LAKE EFFECT BRINGING SNOW TO THE AREA. LACK OF SNOW BEGETS LACK OF SNOW. HUGE STORMS IN THE 5-7 DAY RANGE FIZZLING BEGETS HUGE STORMS IN THE 5-7 DAY RANGE FIZZLING. IT IS THE TREND OF THIS WINTER SO WILL HOLD OFF ON ANY BELLS...OR WHISTLES...AT THIS POINT. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS THE SYSTEM QUICKLY DEPARTS...WINDS WILL SHIFT FROM THE WEST TO THE NORTHWEST. GUSTY WINDS WILL PREVAIL AS THE COLD AIR ADVECTS THROUGH THE REGION. EXPECT LAKE ENHANCED SNOW SHOWERS CAUSING IFR CONDITIONS AT BFD AND JST UNTIL LATE MORNING OR EARLY AFTERNOON. MVFR CIGS AT UNV AND AOO AT TIMES THIS MORNING...AS THE UPPER LVL TROUGH MOVES ACROSS. EXPECT VFR CONDITIONS FURTHER EAST. GENERALLY VFR CONDS EXPECTED ON THU...ALTHOUGH SOME -SHSN ARE POSSIBLE LATE ACROSS NW PA. A SLIGHTLY BETTER CHC OF SNOW OR RAIN SHOWERS FRI...AS A CLIPPER SYSTEM MOVES EASTWARD...JUST NORTH OF PA. VFR CONDS RETURN FOR NEW YEARS WEEKEND. OUTLOOK... THU...GENERALLY VFR. FRI...MVFR/IFR MAINLY WESTERN AREAS WITH RAIN/SNOW SHOWERS. SAT-SUN...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR PAZ004-005- 010. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...TYBURSKI AVIATION...CERU/MARTIN/EVANEGO
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
928 AM EST WED DEC 28 2011 .DISCUSSION... REPORTS FROM THE MOUNTAINS INDICATE BETWEEN 1 AND 4 INCHES OF SNOW HAS FALLEN OVERNIGHT AND THIS MORNING. LIGHT RADAR ECHOS HAVE DIMINISHED FROM EARLIER THIS MORNING...AND THE 12Z OHX SOUNDING SHOWS DRIER AIR WILL ADVECT IN THROUGH THE DAY. CLOUDS ACROSS THE NORTHERN SECTIONS SHOULD BECOME SCATTERED BY MID AFTERNOON ACCORDING TO THE RUC AND NAM. WILL UPDATE TO REMOVE ALL POPS...AND WILL ALLOW THE WINTER WEATHER ADVISORY TO EXPIRE AT 10AM. ONLY MINOR ADJUSTEMENTS WILL BE MADE TO HOURLY TEMPERATURES AND SKY GRIDS FOR THE UPDATE. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR THE FOLLOWING ZONES: BLOUNT SMOKY MOUNTAINS...COCKE SMOKY MOUNTAINS...JOHNSON...SEVIER SMOKY MOUNTAINS...SOUTHEAST CARTER...SOUTHEAST GREENE...UNICOI. VA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR THE FOLLOWING ZONES: WISE. && $$ DGS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
857 PM CST THU DEC 29 2011 .SHORT TERM... 617 PM CST THU DEC 29 2011 CONTINUING TO MONITOR THE CURRENT FORECAST FOR TONIGHT AND HAVE A BIT MORE CONCERN FOR ICING POTENTIAL. THE 29.18Z NAM/GFS ARE GOING TO VERIFY VERY WELL AT 00Z WITH LOW CENTER OVER EAST-CENTRAL NEB AND ECHO SOUTH TO ALMOST KANSAS CITY. THE BAD PART OF THAT VERIFICATION IS THAT THE LOW TRACK ALONG I-80 FROM 29.18Z GFS/NAM WOULD TAKE THE DEFORMATION SOUTH OF THE SNOW FORECAST WE HAVE AND INTO A RAIN ENVIRONMENT. THIS WOULD MAKE MOST OF THE WEATHER A LOW IMPACT SCENARIO AND LESS SNOW OBVIOUSLY. ON THE OTHER HAND... THE LATEST RUC RUNS ARE CONTINUING A BIT FURTHER NORTH TRACK TO THE LOW AND IT BREAKS OUT AN EAST-WEST DEFORMATION ALONG IA-MN BORDER WHICH IS MORE ALONG CURRENT FORECAST IDEA. HOWEVER...THERE IS A SIGNIFICANT WARM LAYER THAT SURGES NORTH INTO THE AREA AHEAD OF THE PRECIPITATION...MAKING A PERIOD OF FREEZING RAIN A SURE BET /PER RUC/ FOR AREAS SEEING SURFACE TEMPERATURES AT OR BELOW 32F. BASED ON CURRENT TEMPERATURES IT MIGHT BE A BAND OF FREEZING RAIN ALONG I-90 ROUGHLY...LIMITED BY >33F TO THE SOUTHWEST /JUST RAIN/. WOULD THINK THAT IF PRECIPITATION IS HEAVY ENOUGH...COLUMN COOLING WOULD HELP TO CHANGE THE TYPE OVER TO SNOW AFTER HOURS TO LIMIT THE ICING. A SNOW/SLEET BAND WOULD BE LIKELY TO THE NORTH OF THAT FZRA...BUT LIGHTER PRECIPITATION THAN CURRENT FORECAST. PLAN TO CONTINUE TO MONITOR INCOMING DATA OVER NEXT TWO HOURS AND TRY TO MAKE ADJUSTMENTS BY 9 PM. BASED ON RUC/HRRR GUIDANCE AND EVEN A BIT WIDER NAM/GFS DEFORMATION BAND...AN ADVISORY FOR ICING CANNOT BE RULED OUT TONIGHT. .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY 334 PM CST THU DEC 29 2011 HIGHLY AMPLIFIED FLOW TO START THE LATER PERIODS WITH LARGE WEEKEND TROUGH OFF TO THE EAST. FAIRLY GOOD AGREEMENT IN MEDIUM RANGE GUIDANCE LEADS TO HIGHER CONFIDENCE IN WHAT LOOKS LIKE A FAIRLY QUIET WEEK TO START NEW YEAR. WINDS WILL REMAIN UP FROM PRESSURE GRADIENT SUNDAY NIGHT BUT RIDGE AXIS SHIFTS IN MONDAY AND TUESDAY DROPPING TEMPERATURES BACK TO SEASONAL NORMALS OR PERHAPS A BIT BELOW FOR A CHANGE. DEPENDING ON WHERE SNOW FALLS FOR NEW YEARS STORM...COULD BE SOME SNOW PACK WHICH WOULD HIGHLY INFLUENCE LOWS...ESPECIALLY TUESDAY MORNING. HAVE LOWERED THEM A BIT AS A TREND. 29.12Z GFS FASTER WITH A SHORT WAVE PASSING THROUGH UPPER RIDGE HEADING INTO TUESDAY NIGHT COMPARED TO 29.12Z ECMWF BUT EITHER WAY THIS FEATURE COULD GENERATE ENOUGH LIFT ON NOSE OF WARMER AIR FOR SNOW THREAT EITHER TUESDAY NIGHT OR WEDNESDAY IN NORTH CENTRAL REGIONS. NOT ENOUGH CONFIDENCE OR COLLABORATION TO INCLUDE AT THIS POINT BUT SMALL CHANCES CAN NOT BE RULED OUT. BEYOND THAT UPPER RIDGE BUILDS IN EVEN STRONGER FOR NATIONS MID-SECTION AND DEPENDING ON ANY LINGERING SNOW COVER...COULD MEAN DRAMATIC WARM UP AGAIN. && .AVIATION...TONIGHT AND FRIDAY 617 PM CST THU DEC 29 2011 FORECAST OVERNIGHT IS A CHALLENGE AS MULTIPLE PRECIPITATION TYPES COULD AFFECT THE TAF SITES. ALSO...CURRENT OBSERVATIONS SUGGEST THE WEATHER CURRENTLY IN THE TAFS COULD SHIFT SOUTH ALTOGETHER...AND INTO IOWA. FOR THIS ISSUANCE...HAVE REMAINED WITH THE IDEA THAT SNOW WOULD FALL OVERNIGHT AT BOTH KLSE/KRST...HOWEVER WITH A WARM AIR SURGE COMING NORTH...AND SURFACE TEMPERATURES RIGHT NEAR FREEZING...AM INCREASINGLY CONCERNED ABOUT FREEZING RAIN AND ICE ACCUMULATION FOR THE AIRPORTS. HAVE ADDED FZRA TO THE TAFS FOR THE OVERNIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES...PRELIM HEADLINES. 856 PM CST THU DEC 29 2011 WI...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST FRIDAY FOR WIZ054-061. MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST FRIDAY FOR MNZ086-087-094-095. IA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST FRIDAY FOR IAZ008>011-018-019-029-030. && $$ SHORT TERM...BAUMGARDT LONG TERM....SHEA AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
617 PM CST THU DEC 29 2011 .SHORT TERM... 617 PM CST THU DEC 29 2011 CONTINUING TO MONITOR THE CURRENT FORECAST FOR TONIGHT AND HAVE A BIT MORE CONCERN FOR ICING POTENTIAL. THE 29.18Z NAM/GFS ARE GOING TO VERIFY VERY WELL AT 00Z WITH LOW CENTER OVER EAST-CENTRAL NEB AND ECHO SOUTH TO ALMOST KANSAS CITY. THE BAD PART OF THAT VERIFICATION IS THAT THE LOW TRACK ALONG I-80 FROM 29.18Z GFS/NAM WOULD TAKE THE DEFORMATION SOUTH OF THE SNOW FORECAST WE HAVE AND INTO A RAIN ENVIRONMENT. THIS WOULD MAKE MOST OF THE WEATHER A LOW IMPACT SCENARIO AND LESS SNOW OBVIOUSLY. ON THE OTHER HAND... THE LATEST RUC RUNS ARE CONTINUING A BIT FURTHER NORTH TRACK TO THE LOW AND IT BREAKS OUT AN EAST-WEST DEFORMATION ALONG IA-MN BORDER WHICH IS MORE ALONG CURRENT FORECAST IDEA. HOWEVER...THERE IS A SIGNIFICANT WARM LAYER THAT SURGES NORTH INTO THE AREA AHEAD OF THE PRECIPITATION...MAKING A PERIOD OF FREEZING RAIN A SURE BET /PER RUC/ FOR AREAS SEEING SURFACE TEMPERATURES AT OR BELOW 32F. BASED ON CURRENT TEMPERATURES IT MIGHT BE A BAND OF FREEZING RAIN ALONG I-90 ROUGHLY...LIMITED BY >33F TO THE SOUTHWEST /JUST RAIN/. WOULD THINK THAT IF PRECIPITATION IS HEAVY ENOUGH...COLUMN COOLING WOULD HELP TO CHANGE THE TYPE OVER TO SNOW AFTER HOURS TO LIMIT THE ICING. A SNOW/SLEET BAND WOULD BE LIKELY TO THE NORTH OF THAT FZRA...BUT LIGHTER PRECIPITATION THAN CURRENT FORECAST. PLAN TO CONTINUE TO MONITOR INCOMING DATA OVER NEXT TWO HOURS AND TRY TO MAKE ADJUSTMENTS BY 9 PM. BASED ON RUC/HRRR GUIDANCE AND EVEN A BIT WIDER NAM/GFS DEFORMATION BAND...AN ADVISORY FOR ICING CANNOT BE RULED OUT TONIGHT. .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY 334 PM CST THU DEC 29 2011 HIGHLY AMPLIFIED FLOW TO START THE LATER PERIODS WITH LARGE WEEKEND TROUGH OFF TO THE EAST. FAIRLY GOOD AGREEMENT IN MEDIUM RANGE GUIDANCE LEADS TO HIGHER CONFIDENCE IN WHAT LOOKS LIKE A FAIRLY QUIET WEEK TO START NEW YEAR. WINDS WILL REMAIN UP FROM PRESSURE GRADIENT SUNDAY NIGHT BUT RIDGE AXIS SHIFTS IN MONDAY AND TUESDAY DROPPING TEMPERATURES BACK TO SEASONAL NORMALS OR PERHAPS A BIT BELOW FOR A CHANGE. DEPENDING ON WHERE SNOW FALLS FOR NEW YEARS STORM...COULD BE SOME SNOW PACK WHICH WOULD HIGHLY INFLUENCE LOWS...ESPECIALLY TUESDAY MORNING. HAVE LOWERED THEM A BIT AS A TREND. 29.12Z GFS FASTER WITH A SHORT WAVE PASSING THROUGH UPPER RIDGE HEADING INTO TUESDAY NIGHT COMPARED TO 29.12Z ECMWF BUT EITHER WAY THIS FEATURE COULD GENERATE ENOUGH LIFT ON NOSE OF WARMER AIR FOR SNOW THREAT EITHER TUESDAY NIGHT OR WEDNESDAY IN NORTH CENTRAL REGIONS. NOT ENOUGH CONFIDENCE OR COLLABORATION TO INCLUDE AT THIS POINT BUT SMALL CHANCES CAN NOT BE RULED OUT. BEYOND THAT UPPER RIDGE BUILDS IN EVEN STRONGER FOR NATIONS MID-SECTION AND DEPENDING ON ANY LINGERING SNOW COVER...COULD MEAN DRAMATIC WARM UP AGAIN. && .AVIATION...TONIGHT AND FRIDAY 617 PM CST THU DEC 29 2011 FORECAST OVERNIGHT IS A CHALLENGE AS MULTIPLE PRECIPITATION TYPES COULD AFFECT THE TAF SITES. ALSO...CURRENT OBSERVATIONS SUGGEST THE WEATHER CURRENTLY IN THE TAFS COULD SHIFT SOUTH ALTOGETHER...AND INTO IOWA. FOR THIS ISSUANCE...HAVE REMAINED WITH THE IDEA THAT SNOW WOULD FALL OVERNIGHT AT BOTH KLSE/KRST...HOWEVER WITH A WARM AIR SURGE COMING NORTH...AND SURFACE TEMPERATURES RIGHT NEAR FREEZING...AM INCREASINGLY CONCERNED ABOUT FREEZING RAIN AND ICE ACCUMULATION FOR THE AIRPORTS. HAVE ADDED FZRA TO THE TAFS FOR THE OVERNIGHT. && .ARX WATCHES/WARNINGS/ADVISORIES... 334 PM CST THU DEC 29 2011 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BAUMGARDT LONG TERM....SHEA AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
316 AM CST FRI DEC 30 2011 .SYNOPSIS... 06Z SFC ANALYSIS HAS A SFC LOW BETWEEN KDNS AND KADU WITH A WARM FRONT RUNNING EAST TO KC75 AND KPNT. A INVERTED TROF RAN INTO ANOTHER WARM FRONT IN NORTHEAST SOUTH DAKOTA AND THEN ANOTHER SFC LOW NORTHEAST OF KBIS. DEW POINTS WERE GENERALLY IN THE 30S WITH 40S FROM THE LOWER MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY. RADAR TRENDS SHOW A BAND OF WAA PRECIPITATION FROM NORTHEAST IOWA INTO NORTHERN ILLINOIS WITH ANOTHER DEVELOPING FROM CENTRAL IOWA INTO CENTRAL ILLINOIS. && .SHORT TERM...TODAY AND TONIGHT A COMBINATION OF NOWCASTING TOOLS AND RUC TRENDS WERE USED TO HANDLE FOR TODAY. THE RUC 300K THETA SFC IN FORCING AND CONDENSATION PRESSURE DEFICITS DEPICTS QUITE WELL WHAT IS CURRENTLY GOING ON. THE INITIAL BAND OF WAA PRECIPITATION WILL ROTATE OUT OF THE CWFA BY 12Z. A NEW BAND OF WAA PRECIPITATION DEVELOPING OVER THE CWFA WILL MOVE ACROSS THE NORTHERN THIRD OF THE CWFA BETWEEN 6 AND 9 AM. WBZ TEMPERATURES AT THE SFC AND 925MB RISE THE REMAINDER OF THE NIGHT AND DURING THE MORNING SO THE PRECIPITATION WILL BE ALL RAIN EXCEPT IN THE HWY 20 CORRIDOR WHERE A MIX IS EXPECTED TO PERSIST DURING THE MORNING. LIFT TOOL INDICATES CONVECTIVE PRECIPITATION DEVELOPING ALONG AND SOUTH OF I-80 THIS MORNING AND RADAR TRENDS DO SUGGEST THIS IS OCCURRING. BY MID DAY THE SFC LOW SHOULD BE OVER THE EASTERN CWFA JUST SOUTH OF I-80 WITH A DEFORMATION ZONE SETTING UP ACROSS THE NORTHERN THIRD OF THE CWFA. WBZ TEMPERATURES AT THE SFC AND 925MB FROM MID DAY THROUGH MID AFTERNOON ARE ABOVE 34 DEGREES SO PRECIPITATION WILL BE ALL RAIN ACROSS THE CWFA. WRF TRENDS...ASSUMING THEY ARE CORRECT...INDICATE WBZ TEMPERATURES DROPPING BACK TO 32 DEGREES OR LOWER FROM 3 TO 6 PM INDICATING A MIX REDEVELOPING NORTH OF HWY 30 WITH A POSSIBLE CHANGE OVER TO ALL SNOW IN THE HWY 20 CORRIDOR. SNOW ACCUMULATIONS TODAY ARE EXPECTED TO BE AN INCH OR LESS. TONIGHT...WRF TRENDS INDICATE PRECIPITATION LINGERING INTO THE EVENING HOURS ACROSS THE EASTERN CWFA. WBZ TEMPERATURES INDICATE A MIX WITH POSSIBLY SOME LIGHT SNOW IN THE HWY 20 CORRIDOR EAST OF DUBUQUE. HOWEVER...CONDENSATION PRESSURE DEFICITS RISE RAPIDLY DURING THE EVENING WITH THE FORCING SHUTTING DOWN. THUS ANY SNOW ACCUMULATION SHOULD BE A DUSTING AT BEST. ..08.. .LONG TERM...SATURDAY THROUGH THURSDAY... THE UPS AND DOWNS MORE ASSOCIATED WITH FALL WEATHER WILL DOMINATE THE EXTENDED FORECAST. SATURDAY SHOULD BE VERY MILD ONCE AGAIN...AS A VERY STRONG SHORT WAVE DIGS INTO THE PLAINS AND RAPIDLY DROPS THE SURFACE PRESSURE OVER THE MIDWEST. THIS WILL DRAW SOUTHERLY WINDS UP OVER THE CWA...WHICH WILL BE MOST CERTAINLY GUSTY AT TIMES. THE DAY SHOULD SHOULD SEE PASSING MID CLOUDS...BUT WITH THE GUSTY WINDS AND SEASONALLY DEEP MIXING...IT SEEMS PRUDENT TO GO ABOVE GUIDANCE FOR HIGHS. THUS...WILL STAY CLOSE TO THE PREVIOUS FORECAST AND GO MID 40S NORTHEAST TO MID 50S SOUTHWEST FOR HIGHS. LOW PRESSURE SHOULD RAPIDLY SHIFT NORTHEAST INTO THE GREAT LAKES...WITH STRONG HIGH PRESSURE RAPIDLY MOVING INTO THE GREAT PLAINS. WINDS JUST ALOFT WILL INCREASE TO 40 TO 50 KTS FROM THE NORTHWEST...BRINGING IN STRONG CAA SATURDAY NIGHT AND SUNDAY. WINDS SHOULD BE PUSHING ADVISORY DURING THIS PERIOD...WITH SUSTAINED WINDS EASILY SEEING AROUND 25 MPH...POSSIBLY 30...AND GUSTS OF 40 TO 45 LIKELY. WILL HIGHLIGHT THIS IN THE HWO. AFTER A SLIGHT TO LOW CHANCE FOR RAIN...POSSIBLY MIXING WITH SNOW NORTHWEST SATURDAY NIGHT...ALL OF WHICH SEEMS LIGHT AND NON HAZARDOUS...WE WILL ONCE AGAIN GO INTO A DRY PATTERN THE REMAINING EXTENDED FORECAST. THUS...THE WIND AND COLD AIR IS THE MAIN STORY FOLLOWING TODAYS PCPN EVENT. WITH TEMPERATURES ALOFT CRASHING DOWN INTO THE -12 TO -17 RANGE AT 850MB...WE WILL BE SEEING THE COLDEST WEATHER IN MANY WEEKS. LOOK FOR SLOWLY FALLING TEMPERATURES IN THE LOWER TO MID 30S SUNDAY...THEN LOWS IN THE TEENS SUNDAY NIGHT. TEMPS WILL ONLY LIKELY RISE TO THE LOWER 20S NORTH TO UPPER 20S SOUTHWEST MONDAY WHICH WILL BE THE COLDEST DAY IN THIS STRETCH. WHILE SHARPLY COLDER THAN LATELY...THESE TEMPERATURES ARE CLOSER TO NORMAL THAN THE RECENT MILD TEMPERATURES. A CHILLY NIGHT MONDAY NIGHT WITH LOWS IN THE 11 TO 18 RANGE FROM NORTH TO SOUTH IS EXPECTED TO GIVE WAY TO WIDESPREAD MILDER AIR AGAIN NEXT WEEK. GLOBAL MODELS AGREE ON SHIFTING THE COLD HIGH PRESSURE EAST TUESDAY...ALLOWING SEVERAL DAYS OF SOUTHWEST FLOW FOR THE MID TO LATE WEEK. THUS...LOOK FOR ANOTHER STAIR STEP UPWARD ON TEMPERATURES...LEADING TO ANOTHER MILD WEDNESDAY AND THURSDAY. WE HAVE GONE WITH MID 30S TO AROUND 40 WEDNESDAY AND AND LOWER TO MID 40S THURSDAY. IT DOES APPEAR THAT WE MAY NEED TO INCREASE THESE TEMPERATURES EVEN FURTHER...AS WE WILL LIKELY HAVE LITTLE MIDWESTERN SNOW COVER AROUND TO HOLD SHALLOW COLD AIR IN PLACE. ..ERVIN.. && .AVIATION... /ISSUED 1149 PM CST THU DEC 29 2011/ THE LOWER CIGS/VSBYS NEAR THE SURFACE LOW IN EASTERN NE HAVE BEEN SLOW TO MATERIALIZE WITH MOST OF THE LOW CIGS/VSBYS WELL NORTH OF THE LOW IN THE COLDER AIR. AS A RESULT THE 06Z TAFS HAVE BACKED OFF ON THE TIMING OF THE IFR OR LOW MVFR CONDITIONS AND KEPT THE LOWER CONDITIONS CLOSE TO THE SURFACE LOW AS IT MOVES THROUGH THE AREA FRIDAY MORNING. THE LOWEST CONDITIONS SHOULD BE SEEN AT KMLI/KCID/KDBQ. BETWEEN 10Z AND 16Z. MOST TAFS SITES WILL SEE PERIODS OF RAIN THROUGH FRIDAY MORNING WITH THE RAIN MIXING WITH OR CHANGING TO LIGHT SNOW AND CONTINUING INTO FRIDAY AFTERNOON. IF ANY ACCUMULATIONS OCCUR THEY SHOULD BE LIMITED TO THE FAR NORTH. INCREASING NORTHWEST WINDS FRIDAY MORNING WILL HELP LIFT CIGS INTO THE MVFR RANGE WITH MVFR CONDITIONS REMAIN OVER THE AREA THROUGH FRIDAY EVENING. ..DLF.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 AM EST FRI DEC 30 2011 .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER THE GRT LKS BTWN LO AMPLITUDE RDGING OVER THE W AND A TROF N JUST OFF THE E COAST. SHRTWV RESPONSIBLE FOR SN ON THU IS PUSHING EWD TOWARD SE ONTARIO...BUT WEAK SFC-H85 TROF REMAINS OVER ERN UPR MI. BUT WITH DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE/DRYING ALF IN THE WAKE OF THE SHRTWV...THE PCPN OVER THE CWA HAS PRETTY MUCH ENDED. THE MQT 88D DOES SHOW HIER RADAR RETURNS OVER ECNTRL LK SUP NEAR WEAK SFC LO CENTER. 00Z INL RAOB SHOWS SHARP INVRN BASE NEAR H875 WITH TEMP JUST BLO THE INVRN DOWN TO -14C...LO ENUF TO SUPPORT LES. ALTHOUGH THE 00Z INL RAOB INDICATES MODEST DRYING IN THE SUB INVRN LYR...SKIES ARE GENERALLY CLDY AT MOST LOCATIONS FM THE MN ARROWHEAD SEWD THRU UPR MI...BUT SOME BREAKS IN THE CLDS ARE EVIDENT. FARTHER TO THE W/SW IN MN/WI...SKIES ARE MOCLR CLOSER TO WEAK SFC RDG AXIS ASSOCIATED WITH INCOMING SHRTWV RDG MOVING E THRU MN. ANOTHER PAIR OF SHRTWVS ARE NOTED IN THE NRN/CNTRL PLAINS...BUT THESE APPEAR TO BE DIGGING TO THE SE. MUCH FARTHER TO THE W...A STRONG SHRTWV IS APRCHG THE PAC NW. UPSTREAM HI TEMPS YDAY SUG MAX TEMPS WL GENERALLY BE ARND 30. && .DISCUSSION... MAIN FCST CONCERNS THIS PACKAGE SHIFT TO POTENTIAL SN EVENT ON NEW YEARS DAY/MON RELATED TO SHRTWV NOW APRCHG THE PAC NW. TDAY...LOOKS LIKE A RELATIVELY QUIET DAY ON TAP WITH WEAK HGT RISES/DRYING ALF IN THE WAKE OF DEPARTING SHRTWV. SHRTWV COMPLEX IN THE PLAINS IS FCST TO CONSOLIDATE IN THE LOWER GRT LKS...WITH ACCOMPANYING DEEP LYR QVECTOR CNVGC/PCPN PASSING S OF UPR MI. FCST SDNGS SHOW INVRN BASE SINKING TO H9-925 OVER THE CWA IN THE AFTN... WITH INVRN BASE TEMPS NO LOWER THAN ABOUT -8C. CONSIDERING THE WEAK SFC WINDS FCST THAT WOULD NOT SUPPORT ORGANIZATION OF LES BANDS...THE MARGINAL NATURE OF THE CHILL/DGZ ABV THE SUB INVRN LYR...AND SOME LLVL DRYING...SUSPECT THERE WL BE LTL IN THE WAKE OF LES. BUT SINCE THE 00Z INL RAOB DID SHOW -14C AIR AT THE H875 INVRN BASE AND THE GFS/NAM MODEL ANALYSIS WAS ABOUT 3C TOO WARM AT THAT SITE...WL MAINTAIN GOING POPS NEAR LK SUP...ESPECIALLY E OFMQT WHERE WEAK SFC TROF IS FCST TO PERSIST THRU THE DAY. ALSO ADDED A MENTION OF FZDZ IN THIS AREA WHERE THE LLVL MSTR REMAINS A BIT MORE RESILIENT AND THE LLVL TEMPS ARE NOT LIKELY TO BE AS LO AS OBSVD AT INL. TNGT...SHRTWV RDGING WL BE DOMINATING WITH WEAK SFC HI PRES RDG AXIS BLDG OVHD. MAINTAINED LO CHC POPS IN THE EVNG OVER THE E WHERE THE SFC LO PRES TROF WL LINGER WHILE SLOWLY WEAKENING WITH TIME. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR SCNTRL WHERE SKIES WL TREND MOCLR UNDER LIGHT SFC ACYC FLOW. SAT...AS SHRTWV COMPLEX NOW MOVING TOWARD THE PAC NW SPLITS AND DEEPENS TROFS IN SCNTRL CAN AND THE CENTRAL PLAINS...INCRSG SW FLOW WL DVLP OVER THE UPR LKS AND RETURN DEEPER MSTR TO THE UPR LKS. WITH INITIAL LLVL DRY AIR...RESTRICTED POPS MAINLY ON SAT AFT TO THE NW HALF OF THE CWA WHERE GUIDANCE SHOWS DEEPER MOISTENING ON CYC SIDE OF UPR JET AXIS ROTATING NEWD TOWARD THE UPR LKS BY 00Z SUN. SFC TEMPS ARE PROGGED TO RISE AOA 32 IN THE AFTN AS H85 TEMPS RISE TO ARND 0C...BUT NAM/SREF FCST WBLB ZERO HGT BLO 500 AGL WITH LINGERING LLVL DRY AIR SUG VERY LTL CHC RA MAY BE MIXED WITH THE PCPN AT THE ONSET. SAT NGT INTO MON...MODELS HAVE BEGUN TO CONVERGE ON A SCENARIO SHOWING A DEEPENING UPR TROF/SFC LO AS SEPARATE SHRTWVS IN SCNTRL CAN AND THE CENTRAL PLAINS PHASE. THE GFS IS MOST AGGRESSIVE AT DEEPENING A CLOSED LO...SHOWING A 984MB SFC LO OVER NRN LK MI BY 12Z SUN. PER NCEP DISCUSSION...USED A BLEND OF THE INTERMEDIATE STRENGTH 00Z NAM/00Z CNDN/21Z SREF/12Z ECMWF FOR FCST PREPARATION. THESE MODELS SHOW SFC LO TRACKING ACRS LK SUP/SRN ONTARIO SAT NGT AND DRAWING ENUF LLVL MSTR OVER UPR MI TO SUPPORT LIKELY POPS UNDER UPR DVGC ON CYC SIDE OF JET AXIS WHERE 12HR H5 FALLS APRCH 200M. WITH THE ARRIVAL OF MORE LLVL MSTR OVER THE E...FCST THKNS/WBLB ZERO HGT SUPPORT AT LEAST A MIX WITH RA IN THAT AREA. ONCE THE LO SHIFTS TO THE NE LATE SAT NGT/SUN...STRONG NW WINDS WITH H85 WINDS AOA 50KT ADVECT MUCH COLDER AIR INTO THE UPR LKS...SETTING UP A LK ENHANCED SN EVENT WITH FCST SDNGS SHOWING DEEP MSTR UNDER LO HGTS AND OMEGA WITHIN THE LOWERING DGZ AND SHARP CYC FLOW. GUSTY NW WINDS WL ALSO RESULT IN CONSIDERABLE BLSN. THIS LK ENHANCED SN WL THEN PERSIST INTO MON BEFORE THE DEEPER MSTR SLOWLY EXITS AND PCPN TENDS TOWARD PURE LES BY MON NGT. CONSIDERED DOING A WATCH FOR THE NW WIND SN BELTS...ESPECIALLY OVER THE W WHERE MOST RECENT NCEP GUIDANCE SHOWS UP TO A FOOT OF SN THRU 12Z MON. BUT SINCE THE BULK OF THE MOST SGNFT WX WL OCCUR IN THE 5TH TO 7TH PERIODS...OPTED TO ISSUE AN SPS TO COVER THIS POTENTIAL WINTER STORM. EXTENDED...LATEST GUIDANCE IN GOOD AGREEMENT SHOWING DEEP UPR TROF GIVING WAY TO A MORE ZONAL FLOW AFT MID WEEK WITH A WARMING TREND. DID LOWER FCST MIN TEMPS A FEW DEGREES FM THE ALLBLEND FCST OVER THE INTERIOR W HALF ON MON NGT GIVEN ARRIVAL OF SFC RDG AXIS/LGT WINDS/PWAT AS LO AS 0.1 INCH. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... LIGHT LOW-LEVEL WIND REGIME THRU THIS FCST PERIOD SUGGESTS CONDITIONS PROBABLY WON`T CHANGE MUCH AT KIWD/KCMX/KSAW. SO...GIVEN THE LOW-LEVEL MOISTURE OVER THE AREA AND GENERAL MVFR CIGS...MVFR CIGS WILL LIKELY PREVAIL THRU THE FCST PERIOD. HOWEVER...THERE MAY BE SOME PERIODS WHERE CLOUDS SCATTER OUT OR CIGS RISE TO VFR AS INDICATED BY CURRENT REGIONAL SFC OBS AND SATELLITE IMAGERY. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... WINDS WILL DIMINISH TODAY AS LOW PRESSURE TROUGH LINGERS OVER LAKE SUPERIOR. A WEAK RIDGE WILL THEN SLIDE ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END GALES ARE LOOKING LIKELY FROM THIS SYSTEM...BEGINNING ON NEW YEARS DAY AND CONTINUING THROUGH MONDAY AS COLDER AIR PLOWS INTO THE GREAT LAKES. HEAVY FREEZING SPRAY ALSO MAY OCCUR SUNDAY NIGHT INTO MONDAY. GALE AND HEAVY FREEZING SPRAY WATCHES WILL LIKELY NEED TO BE ISSUED IN THE NEXT COUPLE DAYS. WINDS DIMINISH SIGNIFICANTLY BY NEXT TUESDAY WITH ARRIVAL OF HIGH PRESSURE RIDGE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...KC DISCUSSION...KC AVIATION...ROLFSON MARINE...TITUS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1148 PM CST THU DEC 29 2011 .AVIATION... NO FLIGHT RESTRICTIONS ARE EXPECTED FROM CEILING AND VISIBILITY IN CENTRAL OR WESTERN NEBRASKA THROUGH FRIDAY EVENING AND OVERNIGHT. AFTER DECREASING TONIGHT BY 08Z...WIND WILL BE 260-280 AT MOST LOCATIONS AT 10-12KT THROUGH THE DAY FRIDAY. && PREV DISCUSSION... /ISSUED 321 PM CST THU DEC 29 2011/ DISCUSSION... SHORT TERM... WIND ADVISORY CONDITIONS ARE SPREADING THROUGH ALL OF THE WRN NEB PANHANDLE THIS AFTERNOON. THERE IS THE POTENTIAL FOR STRONG WINDS TO SPREAD THROUGH ALL OF THE PANHANDLE UNTIL 23Z. THEREAFTER THE LOSS OF DAYTIME HEATING SHOULD CAUSE A DROP IN GUSTS. 30 MPH SUSTAINED CONDITIONS MIGHT CONTINUE THIS EVENING AS LOW PRESSURE TRACKS THROUGH THE MISSOURI BASIN. THE RUC SHOWS A PRONOUNCED TROP FOLD ON THE PV15 SURFACE WHICH SHOULD MOVE THRU THE FCST AREA THIS EVENING. THUS THE WIND ADZY WILL CONTINUE ACROSS GARDEN AND DEUEL COUNTIES WITH A POSSIBLE NORTH AND EAST EXPANSION AS CONDITIONS WARRANT. SCATTERED SHOWERS ISOLATED THUNDERSTORMS ARE EXPECTED TO CONTINUE TRACKING THRU NRN NEB THIS EVENING. THE STRONG WEST WINDS ARE BEING USHERED IN AHEAD OF A PACIFIC COLD FRONT WORKING THRU NERN WY. THE FRONT SHOULD COOL TEMPS OFF SOMEWHAT FOR FRIDAY WITH HIGHS ABOUT 10F COOLER THAN TODAY. ANOTHER STRONG COLD FRONT IS EXPECTED TO MOVE THROUGH SATURDAY MORNING...EARLY AFTERNOON. THIS FRONT IN COMBINATION WITH DEEPENING LOW PRESSURE ACROSS THE UPPER MIDWEST AND VERY STRONG PACIFIC HIGH PRESSURE SHOULD PRODUCE WIND ADVISORY CONDITIONS ACROSS MOST AND POSSIBLY ALL OF THE FCST AREA. A BLEND OF MODEL DATA AND GUIDANCE WAS USED FOR THE FCST WHICH PRODUCED HIGH END WIND ADVISORY CONDITIONS ACROSS SWRN NEB. AMPLE MOISTURE WILL BE PRESENT ALONG AND BEHIND THE FRONT SATURDAY FOR SCATTERED RAIN AND SNOW SHOWERS...MAINLY ACROSS THE NORTH. ANOTHER STRONG TROP FOLD WILL SWEEP THE FCST AREA IN CONCERT WITH THE FRONTAL PASSAGE. THE GFS WAS OVERPOWERING WITH THE WIND STRENGTH AND COLD AIR PRODUCING ALL SNOW WHILE THE NAM SHOWED A MIX WITH WEAKER WINDS. THE WARMER NAM WAS PREFERRED. PACIFIC HIGH PRESSURE WILL BUILD ACROSS THE FCST AREA SUNDAY PRODUCING HIGHS IN THE UPPER 30S TO AROUND 40 WITH NEARLY CLEAR SKIES. LONG TERM... A RIDGE OF HIGH PRESSURE ALOFT WILL BE AMPLIFYING MONDAY ACROSS THE ROCKIES...WHILE A TROUGH OF LOW PRESSURE CONTINUES IT/S EASTWARD PROGRESSION INTO THE NORTHEAST STATES. OUR AREA WILL BE IN BETWEEN THESE TWO FEATURES...WITH A BROAD NORTHWEST FLOW ALOFT. 850 MB TEMPERATURES WILL BEGIN TO RECOVER MONDAY...AND CONTINUE TO WARM THOUGH THURSDAY. IN FACT BY THURSDAY MODELS ARE SUGGESTING +15C OVER THE AREA...WHICH WOULD PUT HIGH TEMPERATURES INTO POSSIBLE RECORD TERRITORY. SO AFTER A COOL START MONDAY...HIGHS MID 30S TO MID 40S...TUESDAY THROUGH THURSDAY LOOKING VERY MILD. COULD BE PUSHING 60 DEGREES OR WARMER AGAIN BY THURSDAY. AVIATION... MID AND HIGH LEVEL CLOUDS WILL CONTINUE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON...WITH SKIES CLEARING TONIGHT. CEILINGS MAY GET AS LOW AS 5000 FT AGL...ALONG WITH A FEW RAIN SHOWERS...ACROSS NORTH CENTRAL NEBRASKA LATE THIS AFTERNOON AND EARLY THIS EVENING. VFR EXPECTED TO PREVAIL...WITH GUSTY WEST WINDS TO 30 KTS WEST OF HIGHWAY 83 FROM LATE AFTERNOON THROUGH THE EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/EXTENDED...WFO LBF AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
350 AM MST FRI DEC 30 2011 .SHORT TERM... (TODAY AND TONIGHT) CURRENTLY...COLORADO WAS UNDER BRISK NW FLOW ALOFT...WITH SOME MTN WAVE CLOUDS SHOWING UP ON SATELLITE OVER THE SW MTS AND THE SANGRES. CONUS IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS SHOWED THAT THE NEXT UPPER SHORTWAVE THAT WILL AFFECT THE REGION BEGINNING LATER TONIGHT WAS JUST MOVING ONSHORE ACROSS THE PAC NW. CLOSER TO HOME...WINDS HAVE FINALLY DIMINISHED AND DECOUPLED FOR THE LOWER ELEVATIONS MAKING FOR A WIDE ARRAY OF SFC TEMPS. GENERALLY...AS OF 3 AM TEMPS HAD DROPPED INTO THE 30S TO UPPER 20S FOR MOST LOCATIONS...AND IN THE SINGLE DIGITS FOR THE SLV. TODAY...RELATIVELY QUIET AND MILD DAY FOR THE CWA TODAY UNDER SHORTWAVE RIDGING...WITH TEMPS WARMING INTO THE UPPER 40S AND 50S FOR THE PLAINS...AND IN THE 40S FOR THE SLV. WINDS ACROSS THE HIGHER ELEVATIONS WILL START TO PICK UP THROUGH LATE AFTN AS THE UPPER DISTURBANCE APPROACHES. TONIGHT...LATEST MODEL RUNS HAVE SEEMED TO SLOW EVERYTHING DOWN BY ABOUT 6 HRS OR SO...AND ARE NOW PLACING THE AXIS OF THE UPPER DISTURBANCE OVER W MONTANA AND IDAHO AT 06Z THIS EVE. THE PRES GRADIENT TIGHTENS AND THE H5 PLAN VIEW PAINTS THE STANDARD HIGH WIND SIGNATURE. MODEL CROSS SECTIONS DO SHOW ABOUT 55 TO 60 KTS AT MT TOP...THEN INCREASE TO 70 KTS BY 12Z. INTERESTING THING IS THAT THE REVERSE SHEAR IS NOW MORE PROMINENT EARLIER IN THE EVENING...WHEN WINDS ARE NOT FORECAST TO BE AS STRONG...THEN AFTER MIDNIGHT WHEN WINDS START TO INCREASE THE REVERSE SHEAR DISAPPEARS. WITH THESE LINGERING QUESTIONS...AND AFTER TALKING TO OUR NEIGHBORS TO THE NORTH...HAVE DECIDED TO KEEP THE WATCH AS IS FOR NOW. HOPEFULLY...THE 12Z RUN WILL BE ENLIGHTENING FOR THE NEXT SHIFT. REGARDLESS...IT WILL GET WINDY ACROSS THE HIGHLIGHT AREAS LATE TONIGHT THROUGH AT LEAST MIDDAY SAT...BUT WHETHER WINDS WILL MEET WARNING CRITERIA IS STILL A QUESTION. MOORE .LONG TERM... ...WINDY SATURDAY... MAIN CONCERN THIS FCST PERIOD IS WINDS FOR SATURDAY. STRONG DISTURBANCE WILL MOVE TO THE NORTH OF THE REGION DURING THIS DAY. STRONG GRADIENT WILL CAUSE STRONG WEST WINDS TO OCCUR DURING THE LATE MORNING AND AFTERNOON. STRONGEST WINDS WILL OCCUR OVER THE HIGHER ELEVATIONS OF THE MTNS AND ACROSS THE N SECTIONS OF THE PLAINS. AS FOR WIND HILITES...DID NOT MAKE ANY CHANGES ATTM AS SIMULATIONS SHOW THE STRONGEST FLOW WHERE CURRENT HILITES ARE IN PLACE. THERE IS A POSSIBILITY THAT WIND HILITES MAY NEED TO BE EXTENDED A BIT FARTHER SOUTH TO COVER PUEBLO...S EL PASO AND POSSIBLY KIOWA COUNTY...AND WILL MAKE THE DAY SHIFT AWARE OF THIS WHEN THEY ARRIVE LATER THIS MORNING. FLOW RAPIDLY DECREASES LATE IN THE DAY ACROSS MOST OF THE REGION EXCEPT THE FAR NE PLAINS. WINDS ARE FCST TO BE NEAR CALM BY 00Z SUNDAY OVER THE I-25 CORRIDOR REGION ON BOTH THE GFS AND NAM. WX AFTER SAT WILL BE RATHER TRANQUIL. A WEAK DISTURBANCE WILL MOVE ACROSS THE REGION DURING THE MID WEEK TIME FRAME...WED-ISH...BUT THIS SYSTEM APPEARS TO BE DRY WITH ONLY A SLIGHT COOLING. THE NEXT CHANCE OF ANY PRECIP WILL LIKELY BE NEXT WEEKEND. /HODANISH && .AVIATION... VFR CONDITIONS EXPECTED AT THE THREE MAIN TAF SITES OF KCOS...KPUB AND KALS FOR THE NEXT 24 HRS. HOWEVER...WINDS ALOFT WILL STAY BRISK THROUGH THE DAY. 700 MB WINDS WILL BEGIN TO STRENGTHEN TONIGHT AFTER 06Z AND BE WNW 50 KTS...WITH 70 KTS AND POTENTIALLY HIGHER AT MTN TOP EXPECTED. THIS WILL CAUSE BLOWING SNOW AND SOME RESTRICTED VSBLY OVER THE PASSES LATE TONIGHT. && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR COZ077-078-083-084. HIGH WIND WATCH FROM LATE TONIGHT THROUGH SATURDAY AFTERNOON FOR COZ072-073-075-076-079>082. && $$ 27/34
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
813 AM CST FRI DEC 30 2011 .UPDATE... SFC LOW IS NOW MOVING INTO KEOKUK COUNTY BASED ON A WEST WIND AT KOOA. SFC LOW IS 1MB DEEPER THAN DEPICTED BY THE RUC. PRESSURE FALLS INDICATE THE SFC LOW WILL CONTINUE MOVING JUST SOUTH OF EAST AND SHOULD PASS BETWEEN KPIA AND KC75 EARLY THIS AFTERNOON. BASED ON SFC AND 925MB WBZ TEMPERATURES ANY RASN MIX IS GENERALLY ALONG AND NORTH OF A KOLZ TO KUGN LINE. RUC TRENDS INDICATE A CHANGE OVER TO ALL RAIN IS COMPLETE. THE QUESTION IS WHAT HAPPENS WITH PTYPE LATER THIS MORNING AND AFTERNOON SINCE THE LOW IS SLIGHTLY STRONGER THAN PROGGED AND THE FACT AN INVERTED TROF WILL BE MOVING THROUGH THE AREA. RUC TRENDS INDICATE 925MB WBZ TEMPERATURES DROPPING BELOW 32 BY MID DAY OVER THE WESTERN THIRD OF THE CWFA AND ROUGHLY THE WESTERN HALF BY MID AFTERNOON. SFC WBZ TEMPERATURES HOWEVER REMAIN AT OR ABOVE 32 DEGREES. MORE IMPORTANTLY...SFC WBZ TEMPERATURES REMAIN AT 34 DEGREES OR HIGHER ALONG OVER ALL BUT THE NORTHWEST QUADRANT OF THE CWFA THROUGH MID AFTERNOON. BY LATE AFTERNOON WBZ TEMPERATURES ARE DROPPING BELOW 34 DEGREES IN THE HWY 20 CORRIDOR EAST OF DUBUQUE. ANOTHER CONCERN IS THE INVERTED TROF IN CENTRAL IOWA. SFC OBS SHOW SNOW IS DEVELOPING WEST OF THE INVERTED TROF WHERE WBZ ARE BELOW 32 DEGREES AT 925MB AND AT OR BELOW 34 DEGREES AT THE SFC. THUS IS APPEARS THAT A RASN MIX WILL MOVE INTO THE NORTHWEST QUADRANT OF THE CWFA STARTING LATE THIS MORNING AND CONTINUING INTO THE AFTERNOON. THERE MAY OR MAY NOT BE A COMPLETE CHANGE OVER IN THIS AREA BUT FCST SOUNDINGS DO SUPPORT A CHANGE OVER TO ALL SNOW. BY LATE AFTERNOON A RASN MIX SHOULD DEVELOP IN THE HWY 20 CORRIDOR FROM DUBUQUE ON EAST WITH A CHANGE OVER POSSIBLE. AN UPDATE REFLECTED ALL THIS WILL BE AVAILABLE SHORTLY. ..08.. && .PREV DISCUSSION... /ISSUED 541 AM CST FRI DEC 30 2011/ AVIATION... SURFACE LOW NEAR KPEA WILL MOV EAST SOUTHEAST AND PASS NEAR KC75 ARND 21Z/30. MVFR TO VFR CONDITIONS WILL BE SEEN AT ALL TAF SITES WITH BRIEF PERIODS OF IFR LIKELY AT KCID/KDBQ/KMLI. COLD AIR ON THE BACKSIDE OF THE STORM IS EXPECTED TO ALLOW A RASN MIX AT ALL TAF SITES AFT 20Z/30 THAT MAY CHANGE TO ALL SN AT KCID/KDBQ. MVFR CONDITIONS ARND 00Z/31 WILL IMPROVE TO VFR BY 06Z/31. .08.. PREV DISCUSSION... /ISSUED 316 AM CST FRI DEC 30 2011/ SYNOPSIS... 06Z SFC ANALYSIS HAS A SFC LOW BETWEEN KDNS AND KADU WITH A WARM FRONT RUNNING EAST TO KC75 AND KPNT. A INVERTED TROF RAN INTO ANOTHER WARM FRONT IN NORTHEAST SOUTH DAKOTA AND THEN ANOTHER SFC LOW NORTHEAST OF KBIS. DEW POINTS WERE GENERALLY IN THE 30S WITH 40S FROM THE LOWER MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY. RADAR TRENDS SHOW A BAND OF WAA PRECIPITATION FROM NORTHEAST IOWA INTO NORTHERN ILLINOIS WITH ANOTHER DEVELOPING FROM CENTRAL IOWA INTO CENTRAL ILLINOIS. SHORT TERM...TODAY AND TONIGHT A COMBINATION OF NOWCASTING TOOLS AND RUC TRENDS WERE USED TO HANDLE FOR TODAY. THE RUC 300K THETA SFC IN FORCING AND CONDENSATION PRESSURE DEFICITS DEPICTS QUITE WELL WHAT IS CURRENTLY GOING ON. THE INITIAL BAND OF WAA PRECIPITATION WILL ROTATE OUT OF THE CWFA BY 12Z. A NEW BAND OF WAA PRECIPITATION DEVELOPING OVER THE CWFA WILL MOVE ACROSS THE NORTHERN THIRD OF THE CWFA BETWEEN 6 AND 9 AM. WBZ TEMPERATURES AT THE SFC AND 925MB RISE THE REMAINDER OF THE NIGHT AND DURING THE MORNING SO THE PRECIPITATION WILL BE ALL RAIN EXCEPT IN THE HWY 20 CORRIDOR WHERE A MIX IS EXPECTED TO PERSIST DURING THE MORNING. LIFT TOOL INDICATES CONVECTIVE PRECIPITATION DEVELOPING ALONG AND SOUTH OF I-80 THIS MORNING AND RADAR TRENDS DO SUGGEST THIS IS OCCURRING. BY MID DAY THE SFC LOW SHOULD BE OVER THE EASTERN CWFA JUST SOUTH OF I-80 WITH A DEFORMATION ZONE SETTING UP ACROSS THE NORTHERN THIRD OF THE CWFA. WBZ TEMPERATURES AT THE SFC AND 925MB FROM MID DAY THROUGH MID AFTERNOON ARE ABOVE 34 DEGREES SO PRECIPITATION WILL BE ALL RAIN ACROSS THE CWFA. WRF TRENDS...ASSUMING THEY ARE CORRECT...INDICATE WBZ TEMPERATURES DROPPING BACK TO 32 DEGREES OR LOWER FROM 3 TO 6 PM INDICATING A MIX REDEVELOPING NORTH OF HWY 30 WITH A POSSIBLE CHANGE OVER TO ALL SNOW IN THE HWY 20 CORRIDOR. SNOW ACCUMULATIONS TODAY ARE EXPECTED TO BE AN INCH OR LESS. TONIGHT...WRF TRENDS INDICATE PRECIPITATION LINGERING INTO THE EVENING HOURS ACROSS THE EASTERN CWFA. WBZ TEMPERATURES INDICATE A MIX WITH POSSIBLY SOME LIGHT SNOW IN THE HWY 20 CORRIDOR EAST OF DUBUQUE. HOWEVER...CONDENSATION PRESSURE DEFICITS RISE RAPIDLY DURING THE EVENING WITH THE FORCING SHUTTING DOWN. THUS ANY SNOW ACCUMULATION SHOULD BE A DUSTING AT BEST. 08.. LONG TERM...SATURDAY THROUGH THURSDAY... THE UPS AND DOWNS MORE ASSOCIATED WITH FALL WEATHER WILL DOMINATE THE EXTENDED FORECAST. SATURDAY SHOULD BE VERY MILD ONCE AGAIN...AS A VERY STRONG SHORT WAVE DIGS INTO THE PLAINS AND RAPIDLY DROPS THE SURFACE PRESSURE OVER THE MIDWEST. THIS WILL DRAW SOUTHERLY WINDS UP OVER THE CWA...WHICH WILL BE MOST CERTAINLY GUSTY AT TIMES. THE DAY SHOULD SHOULD SEE PASSING MID CLOUDS...BUT WITH THE GUSTY WINDS AND SEASONALLY DEEP MIXING...IT SEEMS PRUDENT TO GO ABOVE GUIDANCE FOR HIGHS. THUS...WILL STAY CLOSE TO THE PREVIOUS FORECAST AND GO MID 40S NORTHEAST TO MID 50S SOUTHWEST FOR HIGHS. LOW PRESSURE SHOULD RAPIDLY SHIFT NORTHEAST INTO THE GREAT LAKES...WITH STRONG HIGH PRESSURE RAPIDLY MOVING INTO THE GREAT PLAINS. WINDS JUST ALOFT WILL INCREASE TO 40 TO 50 KTS FROM THE NORTHWEST...BRINGING IN STRONG CAA SATURDAY NIGHT AND SUNDAY. WINDS SHOULD BE PUSHING ADVISORY DURING THIS PERIOD...WITH SUSTAINED WINDS EASILY SEEING AROUND 25 MPH...POSSIBLY 30...AND GUSTS OF 40 TO 45 LIKELY. WILL HIGHLIGHT THIS IN THE HWO. AFTER A SLIGHT TO LOW CHANCE FOR RAIN...POSSIBLY MIXING WITH SNOW NORTHWEST SATURDAY NIGHT...ALL OF WHICH SEEMS LIGHT AND NON HAZARDOUS...WE WILL ONCE AGAIN GO INTO A DRY PATTERN THE REMAINING EXTENDED FORECAST. THUS...THE WIND AND COLD AIR IS THE MAIN STORY FOLLOWING TODAYS PCPN EVENT. WITH TEMPERATURES ALOFT CRASHING DOWN INTO THE -12 TO -17 RANGE AT 850MB...WE WILL BE SEEING THE COLDEST WEATHER IN MANY WEEKS. LOOK FOR SLOWLY FALLING TEMPERATURES IN THE LOWER TO MID 30S SUNDAY...THEN LOWS IN THE TEENS SUNDAY NIGHT. TEMPS WILL ONLY LIKELY RISE TO THE LOWER 20S NORTH TO UPPER 20S SOUTHWEST MONDAY WHICH WILL BE THE COLDEST DAY IN THIS STRETCH. WHILE SHARPLY COLDER THAN LATELY...THESE TEMPERATURES ARE CLOSER TO NORMAL THAN THE RECENT MILD TEMPERATURES. A CHILLY NIGHT MONDAY NIGHT WITH LOWS IN THE 11 TO 18 RANGE FROM NORTH TO SOUTH IS EXPECTED TO GIVE WAY TO WIDESPREAD MILDER AIR AGAIN NEXT WEEK. GLOBAL MODELS AGREE ON SHIFTING THE COLD HIGH PRESSURE EAST TUESDAY...ALLOWING SEVERAL DAYS OF SOUTHWEST FLOW FOR THE MID TO LATE WEEK. THUS...LOOK FOR ANOTHER STAIR STEP UPWARD ON TEMPERATURES...LEADING TO ANOTHER MILD WEDNESDAY AND THURSDAY. WE HAVE GONE WITH MID 30S TO AROUND 40 WEDNESDAY AND AND LOWER TO MID 40S THURSDAY. IT DOES APPEAR THAT WE MAY NEED TO INCREASE THESE TEMPERATURES EVEN FURTHER...AS WE WILL LIKELY HAVE LITTLE MIDWESTERN SNOW COVER AROUND TO HOLD SHALLOW COLD AIR IN PLACE. ERVIN.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
541 AM CST FRI DEC 30 2011 .AVIATION... SURFACE LOW NEAR KPEA WILL MOV EAST SOUTHEAST AND PASS NEAR KC75 ARND 21Z/30. MVFR TO VFR CONDITIONS WILL BE SEEN AT ALL TAF SITES WITH BRIEF PERIODS OF IFR LIKELY AT KCID/KDBQ/KMLI. COLD AIR ON THE BACKSIDE OF THE STORM IS EXPECTED TO ALLOW A RASN MIX AT ALL TAF SITES AFT 20Z/30 THAT MAY CHANGE TO ALL SN AT KCID/KDBQ. MVFR CONDITIONS ARND 00Z/31 WILL IMPROVE TO VFR BY 06Z/31. ..08.. && .PREV DISCUSSION... /ISSUED 316 AM CST FRI DEC 30 2011/ SYNOPSIS... 06Z SFC ANALYSIS HAS A SFC LOW BETWEEN KDNS AND KADU WITH A WARM FRONT RUNNING EAST TO KC75 AND KPNT. A INVERTED TROF RAN INTO ANOTHER WARM FRONT IN NORTHEAST SOUTH DAKOTA AND THEN ANOTHER SFC LOW NORTHEAST OF KBIS. DEW POINTS WERE GENERALLY IN THE 30S WITH 40S FROM THE LOWER MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY. RADAR TRENDS SHOW A BAND OF WAA PRECIPITATION FROM NORTHEAST IOWA INTO NORTHERN ILLINOIS WITH ANOTHER DEVELOPING FROM CENTRAL IOWA INTO CENTRAL ILLINOIS. SHORT TERM...TODAY AND TONIGHT A COMBINATION OF NOWCASTING TOOLS AND RUC TRENDS WERE USED TO HANDLE FOR TODAY. THE RUC 300K THETA SFC IN FORCING AND CONDENSATION PRESSURE DEFICITS DEPICTS QUITE WELL WHAT IS CURRENTLY GOING ON. THE INITIAL BAND OF WAA PRECIPITATION WILL ROTATE OUT OF THE CWFA BY 12Z. A NEW BAND OF WAA PRECIPITATION DEVELOPING OVER THE CWFA WILL MOVE ACROSS THE NORTHERN THIRD OF THE CWFA BETWEEN 6 AND 9 AM. WBZ TEMPERATURES AT THE SFC AND 925MB RISE THE REMAINDER OF THE NIGHT AND DURING THE MORNING SO THE PRECIPITATION WILL BE ALL RAIN EXCEPT IN THE HWY 20 CORRIDOR WHERE A MIX IS EXPECTED TO PERSIST DURING THE MORNING. LIFT TOOL INDICATES CONVECTIVE PRECIPITATION DEVELOPING ALONG AND SOUTH OF I-80 THIS MORNING AND RADAR TRENDS DO SUGGEST THIS IS OCCURRING. BY MID DAY THE SFC LOW SHOULD BE OVER THE EASTERN CWFA JUST SOUTH OF I-80 WITH A DEFORMATION ZONE SETTING UP ACROSS THE NORTHERN THIRD OF THE CWFA. WBZ TEMPERATURES AT THE SFC AND 925MB FROM MID DAY THROUGH MID AFTERNOON ARE ABOVE 34 DEGREES SO PRECIPITATION WILL BE ALL RAIN ACROSS THE CWFA. WRF TRENDS...ASSUMING THEY ARE CORRECT...INDICATE WBZ TEMPERATURES DROPPING BACK TO 32 DEGREES OR LOWER FROM 3 TO 6 PM INDICATING A MIX REDEVELOPING NORTH OF HWY 30 WITH A POSSIBLE CHANGE OVER TO ALL SNOW IN THE HWY 20 CORRIDOR. SNOW ACCUMULATIONS TODAY ARE EXPECTED TO BE AN INCH OR LESS. TONIGHT...WRF TRENDS INDICATE PRECIPITATION LINGERING INTO THE EVENING HOURS ACROSS THE EASTERN CWFA. WBZ TEMPERATURES INDICATE A MIX WITH POSSIBLY SOME LIGHT SNOW IN THE HWY 20 CORRIDOR EAST OF DUBUQUE. HOWEVER...CONDENSATION PRESSURE DEFICITS RISE RAPIDLY DURING THE EVENING WITH THE FORCING SHUTTING DOWN. THUS ANY SNOW ACCUMULATION SHOULD BE A DUSTING AT BEST. .08.. LONG TERM...SATURDAY THROUGH THURSDAY... THE UPS AND DOWNS MORE ASSOCIATED WITH FALL WEATHER WILL DOMINATE THE EXTENDED FORECAST. SATURDAY SHOULD BE VERY MILD ONCE AGAIN...AS A VERY STRONG SHORT WAVE DIGS INTO THE PLAINS AND RAPIDLY DROPS THE SURFACE PRESSURE OVER THE MIDWEST. THIS WILL DRAW SOUTHERLY WINDS UP OVER THE CWA...WHICH WILL BE MOST CERTAINLY GUSTY AT TIMES. THE DAY SHOULD SHOULD SEE PASSING MID CLOUDS...BUT WITH THE GUSTY WINDS AND SEASONALLY DEEP MIXING...IT SEEMS PRUDENT TO GO ABOVE GUIDANCE FOR HIGHS. THUS...WILL STAY CLOSE TO THE PREVIOUS FORECAST AND GO MID 40S NORTHEAST TO MID 50S SOUTHWEST FOR HIGHS. LOW PRESSURE SHOULD RAPIDLY SHIFT NORTHEAST INTO THE GREAT LAKES...WITH STRONG HIGH PRESSURE RAPIDLY MOVING INTO THE GREAT PLAINS. WINDS JUST ALOFT WILL INCREASE TO 40 TO 50 KTS FROM THE NORTHWEST...BRINGING IN STRONG CAA SATURDAY NIGHT AND SUNDAY. WINDS SHOULD BE PUSHING ADVISORY DURING THIS PERIOD...WITH SUSTAINED WINDS EASILY SEEING AROUND 25 MPH...POSSIBLY 30...AND GUSTS OF 40 TO 45 LIKELY. WILL HIGHLIGHT THIS IN THE HWO. AFTER A SLIGHT TO LOW CHANCE FOR RAIN...POSSIBLY MIXING WITH SNOW NORTHWEST SATURDAY NIGHT...ALL OF WHICH SEEMS LIGHT AND NON HAZARDOUS...WE WILL ONCE AGAIN GO INTO A DRY PATTERN THE REMAINING EXTENDED FORECAST. THUS...THE WIND AND COLD AIR IS THE MAIN STORY FOLLOWING TODAYS PCPN EVENT. WITH TEMPERATURES ALOFT CRASHING DOWN INTO THE -12 TO -17 RANGE AT 850MB...WE WILL BE SEEING THE COLDEST WEATHER IN MANY WEEKS. LOOK FOR SLOWLY FALLING TEMPERATURES IN THE LOWER TO MID 30S SUNDAY...THEN LOWS IN THE TEENS SUNDAY NIGHT. TEMPS WILL ONLY LIKELY RISE TO THE LOWER 20S NORTH TO UPPER 20S SOUTHWEST MONDAY WHICH WILL BE THE COLDEST DAY IN THIS STRETCH. WHILE SHARPLY COLDER THAN LATELY...THESE TEMPERATURES ARE CLOSER TO NORMAL THAN THE RECENT MILD TEMPERATURES. A CHILLY NIGHT MONDAY NIGHT WITH LOWS IN THE 11 TO 18 RANGE FROM NORTH TO SOUTH IS EXPECTED TO GIVE WAY TO WIDESPREAD MILDER AIR AGAIN NEXT WEEK. GLOBAL MODELS AGREE ON SHIFTING THE COLD HIGH PRESSURE EAST TUESDAY...ALLOWING SEVERAL DAYS OF SOUTHWEST FLOW FOR THE MID TO LATE WEEK. THUS...LOOK FOR ANOTHER STAIR STEP UPWARD ON TEMPERATURES...LEADING TO ANOTHER MILD WEDNESDAY AND THURSDAY. WE HAVE GONE WITH MID 30S TO AROUND 40 WEDNESDAY AND AND LOWER TO MID 40S THURSDAY. IT DOES APPEAR THAT WE MAY NEED TO INCREASE THESE TEMPERATURES EVEN FURTHER...AS WE WILL LIKELY HAVE LITTLE MIDWESTERN SNOW COVER AROUND TO HOLD SHALLOW COLD AIR IN PLACE. .ERVIN.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
958 AM EST FRI DEC 30 2011 .SYNOPSIS... LOW PRESSURE WILL STRENGTHEN OVER THE CENTRAL MIDWEST REGION THROUGH TONIGHT...BEFORE MOVING INTO NEW ENGLAND ON SATURDAY. A COLD FRONT WILL CROSS THE REGION SATURDAY MORNING. HIGH PRESSURE WILL RETURN TO THE REGION SATURDAY NIGHT BEFORE MOVING OFF THE COAST SUNDAY. A STRONG COLD FRONT WILL ARRIVE LATE SUNDAY NIGHT AND WILL USHER IN BLUSTERY ARCTIC AIR MONDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... LATEST WV SAT LOOP SHOWS AN UPPER LOW SPINNING OVER ERN IA THIS MRNG. A POTENT ULVL JET STREAK DIGGING ON THE WRN SIDE OF THE LOW WILL LEAD TO AMPLIFICATION OF THE TROUGH AS IT MOVES TOWARD THE OH VLY BY LATE TDA. SYNOPTIC-SCALE FLOW AHEAD OF THE LOW WILL BACK AND STRENGTHEN OVER THE ERN CONUS. DOWNSTREAM IMPACTS IN THE MID-ATLANTIC FROM THE DEVELOPING S-SW FLOW INCLUDE ADVECTION OF MILDER AIR AND AN INCREASE IN MID-HI CLOUDS THRUOUT THE DAY. CLOUD COVER WILL VARY ACROSS THE CWA...BUT ON AVG WILL RANGE FROM PARTLY SUNNY ACROSS SRN MD TO CLOUDY ALONG THE ALLEGHENY FRONT. DESPITE LIMITED DAYTIME HEATING FROM THE CLOUD COVER...MAX TEMPS WILL STILL REACH THE LOW/MID 50S AS A WARM AIRMASS IS IN PLACE /12Z IAD RAOB SHOWS 9C LAYER AT THE TOP OF THE NOCTURNAL INVERSION/. LATEST RADAR LOOP OVERLAID WITH RUC ANALYSIS SHOWS LGT RETURNS CROSSING THE APPALACHIANS IN ASSOCIATION WITH A BAND OF LOW-MID LVL ISENTROPIC LIFT/CONVERGENCE WELL AHEAD OF THE LOW AND IN THE LEFT-EXIT REGION OF AN UPPER JET STREAK. HAVE ADDED ISO LGT RAIN SHOWERS AND SPRINKLES INTO THE FCST FOR THE POTOMAC HIGHLANDS FROM LATE THIS MRNG THRU THE ERY AFTN. TONIGHT...UPR TROUGH ASSOCIATED WITH THE MIDWEST LOW CROSSES THE CWA AFTER MIDNIGHT. DPVA ASSOCIATED WITH THIS TROUGH WILL PRODUCE LOW/MID- LEVEL CLOUDS. THEREFORE...LOW CHANCES FOR LIGHT RAIN SHOWERS WERE EXPANDED ACROSS THE CWA. HOWEVER...LIMITED MOISTURE AND DOWNSLOPING LOW-LEVEL FLOW WILL KEEP ANY DEVELOPMENT AS LIGHT/SPRINKLES. LIKELY POPS FOR THE FAR WRN SLOPES OF THE HIGHLANDS. MILD NIGHT FOR LATE DECEMBER...WITH SLY FLOW AND CLOUDS...SO PTYPE TNGT WILL BE RAIN. MIN TEMPS MID/UPPER 30S WEST OF THE BLUE RIDGE...UPR 30S TO LOW 40S EAST /IN URBAN AND NEAR- SHORE LOCALES/...ABOUT 10 DEGREES ABOVE NORMAL. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... UPR RDG WILL BE FOUND OVER MID-ATLC RGN ON SAT. SHRTWV TROF OVER CNTRL PLNS AND A SECOND SHRTWV TROF OVER S-CNTRL CANADA WILL PHASE IN GRTLKS RGN SAT NGT...LEADING TO DP CLOSED LOW OVER MI. LOW-LVL JET WILL STRENGTHEN OVER MID-ATLC RGN ON SUN IN RESPONSE TO STRENGTHENING LOW IN GRTLKS. WARM AIR ADVCTN WILL ENSURE THAT ANY PCPN ON SUN FALLS AS RAIN. BUT WINDS WILL BCM WLY AND QUITE GUSTY AS SFC TROF CROSSES THE RGN. BY LATE AFTN...COLDER AIR MAY BE BANKED AGAINST THE APLCNS. MAXIMA THIS WKEND WILL CONT TO BE QUITE MILD IN THE MID-UPR 50S. MINIMA SAT NGT WILL BE NR NRML...IN THE LOW-MID 30S. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... CLOSED UPR LOW ON SUN WILL BE LOCATED JUST N OF GRTLKS RGN AND WILL SPAN MUCH OF THE ERN CONUS. H5 RDG WILL AMPLIFY OVER WRN CONUS. A SHRTWV TROF WILL MOVE SWD INTO THE CONUS AHD OF THIS RDG AND WILL DISLODGE ARCTIC AMS. THIS COLD AMS WILL MOVE INTO THE GRTLKS RGN ON MON AND INTO NEW ENGLAND BY TUE. MODEST MSTR AHEAD OF THIS APRCHG SHRTWV TROF AND COLD ADVCTN ALOFT ASSOCIATED WITH THE WAVE WILL LEAD TO SGFNT INSTBY ALONG WRN SLOPES OF POTOMAC HIGHLANDS FOR A PROLONGED PD MON-TUE MRNG. WITH MAXIMA XPCD TO RMN BLW FRZG IN THESE ZONES...SGFNT SNOW ACCUMS XPCD...LKLY WARRANTING WINTER HEADLINES AS THE TIME NRS. WINDS ALSO WILL BE OF CONCERN DURG THIS EVENT...LEADING TO HAZARDOUS WIND CHILLS AND POOR VSBYS. ANY PCPN THAT CROSSES THE MTNS WILL BE VERY LGT OWING TO DOWNSLOPING FLOW. STRONG COLD ADVCTN WILL OCCUR ON TUE AS ARCTIC AMS OVERTAKES THE NERN CONUS. H9 TEMPS AS LOW AS 10 TO 15 BLW ZERO COULD LEAD TO MAXIMA IN THE MID-UPR 20S AND MINIMA IN TEENS...WITH SINGLE DIGIT TEMPS XPCD AT HIGHER ELEVATIONS. ANY ONGOING SNOW SHWRS ON WRN SLOPES WILL COME TO AN END AS SFC HIPRES BUILDS INTO THE RGN. SFC RDG WILL BE LOCATED IN MID- ATLC RGN ON WED. MAXIMA WERE UNDERCUT BY SVRL DEG F ON TUE. MINIMA TUE NGT IN PARTICULAR WILL BE VERY COLD AS SFC HIPRES BUILDS. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... VFR WITH SLY FLOW 5-10 KT TODAY. MID AND HIGH CLOUDS DURING THE DAY WILL GRADUALLY LOWER TO 3-6 KFT OVNGT AS A COLD FRONT APPROACHES FROM THE WEST. SHRA POSSIBLE DURING THIS TIME AS THE FRONT MOVES THRU. ANY SHOWER ACTIVITY WILL BE ISO AND LGT. VFR CONDS WILL CONT THRU NEXT WK. BUT SGFNT WIND WILL BE OF CONCERN TO AVIATION INTERESTS AS SFC TROF AND CDFNT ARRIVE EARLY NEXT WK. SGFNT TURBULENCE CAN BE ANTICIPATED. && .MARINE... SLY/SSWLY FLOW INCREASES TODAY AHEAD OF A COLD FRONT THAT MOVES THRU EARLY SATURDAY. SMALL CRAFT ADVISORY GOES INTO EFFECT AT 2PM SOUTH OF DRUM PT...THEN UP THE MAIN CHANNEL OF THE BAY /SOUTH OF POOLES ISLAND/ AND LOWER TIDAL POTOMAC RIVER FOR TONIGHT. MAX GUSTS EXPECTED AROUND 20 KT. SMALL CRAFT ADZY WAS EXPANDED TO ALL ZONES ON SAT AS CDFNT CROSSES THE RGN. WINDS WILL SUBSIDE SAT NGT AS HIPRES BUILDS. SFC TROF AND SUBSEQUENT CDFNT ASSOCIATED WITH ARCTIC AMS WILL IMPACT THE WATERS EARLY NEXT WK. SMALL CRAFT ADZY WILL BE NEEDED. GALE WRNG MAY BE NEEDED DURG THIS TIME. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST SATURDAY FOR ANZ530- 535-536-538-539-542. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM EST SATURDAY FOR ANZ534-543. SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 6 PM EST SATURDAY FOR ANZ531>533-537-540-541. && $$ UPDATE...KLEIN PREV DISC...JACKSON/KRAMAR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
636 AM EST FRI DEC 30 2011 UPDATED AVIATION DISCUSSION FOR 12Z TAFS .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER THE GRT LKS BTWN LO AMPLITUDE RDGING OVER THE W AND A TROF N JUST OFF THE E COAST. SHRTWV RESPONSIBLE FOR SN ON THU IS PUSHING EWD TOWARD SE ONTARIO...BUT WEAK SFC-H85 TROF REMAINS OVER ERN UPR MI. BUT WITH DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE/DRYING ALF IN THE WAKE OF THE SHRTWV...THE PCPN OVER THE CWA HAS PRETTY MUCH ENDED. THE MQT 88D DOES SHOW HIER RADAR RETURNS OVER ECNTRL LK SUP NEAR WEAK SFC LO CENTER. 00Z INL RAOB SHOWS SHARP INVRN BASE NEAR H875 WITH TEMP JUST BLO THE INVRN DOWN TO -14C...LO ENUF TO SUPPORT LES. ALTHOUGH THE 00Z INL RAOB INDICATES MODEST DRYING IN THE SUB INVRN LYR...SKIES ARE GENERALLY CLDY AT MOST LOCATIONS FM THE MN ARROWHEAD SEWD THRU UPR MI...BUT SOME BREAKS IN THE CLDS ARE EVIDENT. FARTHER TO THE W/SW IN MN/WI...SKIES ARE MOCLR CLOSER TO WEAK SFC RDG AXIS ASSOCIATED WITH INCOMING SHRTWV RDG MOVING E THRU MN. ANOTHER PAIR OF SHRTWVS ARE NOTED IN THE NRN/CNTRL PLAINS...BUT THESE APPEAR TO BE DIGGING TO THE SE. MUCH FARTHER TO THE W...A STRONG SHRTWV IS APRCHG THE PAC NW. UPSTREAM HI TEMPS YDAY SUG MAX TEMPS WL GENERALLY BE ARND 30. && .DISCUSSION... MAIN FCST CONCERNS THIS PACKAGE SHIFT TO POTENTIAL SN EVENT ON NEW YEARS DAY/MON RELATED TO SHRTWV NOW APRCHG THE PAC NW. TDAY...LOOKS LIKE A RELATIVELY QUIET DAY ON TAP WITH WEAK HGT RISES/DRYING ALF IN THE WAKE OF DEPARTING SHRTWV. SHRTWV COMPLEX IN THE PLAINS IS FCST TO CONSOLIDATE IN THE LOWER GRT LKS...WITH ACCOMPANYING DEEP LYR QVECTOR CNVGC/PCPN PASSING S OF UPR MI. FCST SDNGS SHOW INVRN BASE SINKING TO H9-925 OVER THE CWA IN THE AFTN... WITH INVRN BASE TEMPS NO LOWER THAN ABOUT -8C. CONSIDERING THE WEAK SFC WINDS FCST THAT WOULD NOT SUPPORT ORGANIZATION OF LES BANDS...THE MARGINAL NATURE OF THE CHILL/DGZ ABV THE SUB INVRN LYR...AND SOME LLVL DRYING...SUSPECT THERE WL BE LTL IN THE WAKE OF LES. BUT SINCE THE 00Z INL RAOB DID SHOW -14C AIR AT THE H875 INVRN BASE AND THE GFS/NAM MODEL ANALYSIS WAS ABOUT 3C TOO WARM AT THAT SITE...WL MAINTAIN GOING POPS NEAR LK SUP...ESPECIALLY E OFMQT WHERE WEAK SFC TROF IS FCST TO PERSIST THRU THE DAY. ALSO ADDED A MENTION OF FZDZ IN THIS AREA WHERE THE LLVL MSTR REMAINS A BIT MORE RESILIENT AND THE LLVL TEMPS ARE NOT LIKELY TO BE AS LO AS OBSVD AT INL. TNGT...SHRTWV RDGING WL BE DOMINATING WITH WEAK SFC HI PRES RDG AXIS BLDG OVHD. MAINTAINED LO CHC POPS IN THE EVNG OVER THE E WHERE THE SFC LO PRES TROF WL LINGER WHILE SLOWLY WEAKENING WITH TIME. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR SCNTRL WHERE SKIES WL TREND MOCLR UNDER LIGHT SFC ACYC FLOW. SAT...AS SHRTWV COMPLEX NOW MOVING TOWARD THE PAC NW SPLITS AND DEEPENS TROFS IN SCNTRL CAN AND THE CENTRAL PLAINS...INCRSG SW FLOW WL DVLP OVER THE UPR LKS AND RETURN DEEPER MSTR TO THE UPR LKS. WITH INITIAL LLVL DRY AIR...RESTRICTED POPS MAINLY ON SAT AFT TO THE NW HALF OF THE CWA WHERE GUIDANCE SHOWS DEEPER MOISTENING ON CYC SIDE OF UPR JET AXIS ROTATING NEWD TOWARD THE UPR LKS BY 00Z SUN. SFC TEMPS ARE PROGGED TO RISE AOA 32 IN THE AFTN AS H85 TEMPS RISE TO ARND 0C...BUT NAM/SREF FCST WBLB ZERO HGT BLO 500 AGL WITH LINGERING LLVL DRY AIR SUG VERY LTL CHC RA MAY BE MIXED WITH THE PCPN AT THE ONSET. SAT NGT INTO MON...MODELS HAVE BEGUN TO CONVERGE ON A SCENARIO SHOWING A DEEPENING UPR TROF/SFC LO AS SEPARATE SHRTWVS IN SCNTRL CAN AND THE CENTRAL PLAINS PHASE. THE GFS IS MOST AGGRESSIVE AT DEEPENING A CLOSED LO...SHOWING A 984MB SFC LO OVER NRN LK MI BY 12Z SUN. PER NCEP DISCUSSION...USED A BLEND OF THE INTERMEDIATE STRENGTH 00Z NAM/00Z CNDN/21Z SREF/12Z ECMWF FOR FCST PREPARATION. THESE MODELS SHOW SFC LO TRACKING ACRS LK SUP/SRN ONTARIO SAT NGT AND DRAWING ENUF LLVL MSTR OVER UPR MI TO SUPPORT LIKELY POPS UNDER UPR DVGC ON CYC SIDE OF JET AXIS WHERE 12HR H5 FALLS APRCH 200M. WITH THE ARRIVAL OF MORE LLVL MSTR OVER THE E...FCST THKNS/WBLB ZERO HGT SUPPORT AT LEAST A MIX WITH RA IN THAT AREA. ONCE THE LO SHIFTS TO THE NE LATE SAT NGT/SUN...STRONG NW WINDS WITH H85 WINDS AOA 50KT ADVECT MUCH COLDER AIR INTO THE UPR LKS...SETTING UP A LK ENHANCED SN EVENT WITH FCST SDNGS SHOWING DEEP MSTR UNDER LO HGTS AND OMEGA WITHIN THE LOWERING DGZ AND SHARP CYC FLOW. GUSTY NW WINDS WL ALSO RESULT IN CONSIDERABLE BLSN. THIS LK ENHANCED SN WL THEN PERSIST INTO MON BEFORE THE DEEPER MSTR SLOWLY EXITS AND PCPN TENDS TOWARD PURE LES BY MON NGT. CONSIDERED DOING A WATCH FOR THE NW WIND SN BELTS...ESPECIALLY OVER THE W WHERE MOST RECENT NCEP GUIDANCE SHOWS UP TO A FOOT OF SN THRU 12Z MON. BUT SINCE THE BULK OF THE MOST SGNFT WX WL OCCUR IN THE 5TH TO 7TH PERIODS...OPTED TO ISSUE AN SPS TO COVER THIS POTENTIAL WINTER STORM. EXTENDED...LATEST GUIDANCE IN GOOD AGREEMENT SHOWING DEEP UPR TROF GIVING WAY TO A MORE ZONAL FLOW AFT MID WEEK WITH A WARMING TREND. DID LOWER FCST MIN TEMPS A FEW DEGREES FM THE ALLBLEND FCST OVER THE INTERIOR W HALF ON MON NGT GIVEN ARRIVAL OF SFC RDG AXIS/LGT WINDS/PWAT AS LO AS 0.1 INCH. && .AVIATION /FOR THE 12Z TAF ISSUANCE/... LIGHT LOW-LEVEL WIND REGIME THRU THIS FCST PERIOD SUGGESTS CONDITIONS PROBABLY WILL NOT CHANGE MUCH AT KIWD/KCMX/KSAW. SO...GIVEN THE LOW-LEVEL MOISTURE OVER THE AREA AND GENERAL MVFR CIGS...MVFR CIGS WILL LIKELY PREVAIL THRU THE FCST PERIOD. HOWEVER...THERE MAY BE SOME PERIODS WHERE CLOUDS SCATTER OUT OR CIGS RISE TO VFR AS INDICATED BY CURRENT REGIONAL SFC OBS AND SATELLITE IMAGERY. FG AS SAW SHOULD BURN OFF THIS MORNING AS SURFACE TEMPS INCREASE. FG MAY FORM AT CMX TONIGHT GIVEN ABUNDANT LOW LEVEL MOISTURE...IF CLOUDS CAN CLEAR OUT ENOUGH. THE EXACT TIMING IS STILL IN QUESTION. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... WINDS WILL DIMINISH TODAY AS LOW PRESSURE TROUGH LINGERS OVER LAKE SUPERIOR. A WEAK RIDGE WILL THEN SLIDE ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END GALES ARE LOOKING LIKELY FROM THIS SYSTEM...BEGINNING ON NEW YEARS DAY AND CONTINUING THROUGH MONDAY AS COLDER AIR PLOWS INTO THE GREAT LAKES. HEAVY FREEZING SPRAY ALSO MAY OCCUR SUNDAY NIGHT INTO MONDAY. GALE AND HEAVY FREEZING SPRAY WATCHES WILL LIKELY NEED TO BE ISSUED IN THE NEXT COUPLE DAYS. WINDS DIMINISH SIGNIFICANTLY BY NEXT TUESDAY WITH ARRIVAL OF HIGH PRESSURE RIDGE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...KC DISCUSSION...KC AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1122 AM MST FRI DEC 30 2011 .UPDATE... UPDATED TO BOOST TEMPERATURES IN THE LEE OF THE MTS WHERE READINGS ALREADY APPROACHING FCST HIGHS OF MID 50S. COULD SEE A RIBBON OF 60 DEGREE READINGS IN THESE AREAS. ALSO FINE TUNED WIND GRIDS IN THE UPPER ARKANSAS RIVER AND NRN EL PASO COUNTY WHERE GUSTY SOUTHWEST WINDS HAVE ALREADY MIXED DOWN THE SURFACE. AS FOR HIGH WIND HIGHLIGHTS LATER TONIGHT INTO SATURDAY...WILL LIKELY BE TAKING MOST OF THE AREA TO WARNINGS WITH NEXT FORECAST UPDATE/ISSUANCE. MTN TOP WINDS INCREASE TO 50-60 KTS OVERNIGHT...AND TO 65 TO 70 KTS BY SATURDAY MORNING WHICH SHOULD EASILY MEET HIGH WIND CRITERIA FOR THE ZONES ABOVE 11KFT. WILL PROBABLY ADD HIGHER ELEVATIONS OF CHAFFEE/LAKE COUNTIES AS WELL...WHERE STRONG WINDS WILL LIKELY CAUSE BLOWING SNOW ISSUES. CHALLENGE WILL BE HOW FAR DOWN THE SLOPES THE STRONGEST WINDS WILL DESCEND. IT WILL BE WINDY ALL AREAS TOMORROW...HOWEVER MTN WAVE PARAMETERS ARE NOT THAT FAVORABLE. BUT WITH STRONG DOWNWARD FORCING MOVING ACROSS THE AREA SAT MORNING BEHIND TROF AXIS...NAM12 HAS 50 KT WINDS DESCENDING TO 800 MB ACROSS PORTIONS OF PUEBLO...AND KIOWA COUNTIES. MIXING SHOULD BE DEEP ENOUGH TO TAP THESE WINDS FOR POTENTIAL WIND GUSTS. WILL WAIT FOR LOCAL 4 KM WRF MODEL RUN BEFORE DECIDING TO THROW IN THESE ZONES ALONG WITH SRN EL PASO COUNTY INTO HIGHLIGHT AREA. -KT && .PREV DISCUSSION... /ISSUED 1041 AM MST FRI DEC 30 2011/ AVIATION... LIGHT SOUTHEAST WINDS WILL PERSIST THROUGH THE EARLY AFTERNOON FOR KCOS AND KPUB BEFORE WINDS INCREASE FROM THE SOUTH TO SOUTHWEST 10-15 KTS. WINDS AT KCOS WILL SHIFT AROUND FROM THE NORTH BY EARLY EVENING...WITH KPUB MAINTAINING A WEST WIND AROUND 10KTS THROUGH THE OVERNIGHT HOURS. AT THIS TIME...WITHOUT STRONG MTN WAVE PARAMETERS IN PLACE...THINK ANY LOW LEVEL WIND SHEAR WILL STAY TO THE WEST OF THE TAF SITES...BUT THIS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT...ESPECIALLY AT KCOS. EXPECT THAT WINDS WILL INCREASE ABRUPTLY AT KCOS AROUND 15Z ON SAT...AND AT 16-17Z AT KPUB WITH GUSTS TO AROUND 40 KTS. WINDS WILL REMAIN LIGHT AT KALS THROUGH THE PERIOD. GUSTY WINDS AT MTN TOP LEVELS ALONG WITH A ROUND OF SNOW TOMORROW MORNING WILL PRODUCE MTN OBSCURATIONS AT TIMES WITH BLOWING SNOW. WINDS AT MTN TOP LEVEL WILL BE SUSTAINED AROUND 50-60 KTS STARTING AROUND 06Z TONIGHT AND CONTINUING THROUGH TOMORROW. -KT PREV DISCUSSION... /ISSUED 350 AM MST FRI DEC 30 2011/ SHORT TERM... (TODAY AND TONIGHT) CURRENTLY...COLORADO WAS UNDER BRISK NW FLOW ALOFT...WITH SOME MTN WAVE CLOUDS SHOWING UP ON SATELLITE OVER THE SW MTS AND THE SANGRES. CONUS IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS SHOWED THAT THE NEXT UPPER SHORTWAVE THAT WILL AFFECT THE REGION BEGINNING LATER TONIGHT WAS JUST MOVING ONSHORE ACROSS THE PAC NW. CLOSER TO HOME...WINDS HAVE FINALLY DIMINISHED AND DECOUPLED FOR THE LOWER ELEVATIONS MAKING FOR A WIDE ARRAY OF SFC TEMPS. GENERALLY...AS OF 3 AM TEMPS HAD DROPPED INTO THE 30S TO UPPER 20S FOR MOST LOCATIONS...AND IN THE SINGLE DIGITS FOR THE SLV. TODAY...RELATIVELY QUIET AND MILD DAY FOR THE CWA TODAY UNDER SHORTWAVE RIDGING...WITH TEMPS WARMING INTO THE UPPER 40S AND 50S FOR THE PLAINS...AND IN THE 40S FOR THE SLV. WINDS ACROSS THE HIGHER ELEVATIONS WILL START TO PICK UP THROUGH LATE AFTN AS THE UPPER DISTURBANCE APPROACHES. TONIGHT...LATEST MODEL RUNS HAVE SEEMED TO SLOW EVERYTHING DOWN BY ABOUT 6 HRS OR SO...AND ARE NOW PLACING THE AXIS OF THE UPPER DISTURBANCE OVER W MONTANA AND IDAHO AT 06Z THIS EVE. THE PRES GRADIENT TIGHTENS AND THE H5 PLAN VIEW PAINTS THE STANDARD HIGH WIND SIGNATURE. MODEL CROSS SECTIONS DO SHOW ABOUT 55 TO 60 KTS AT MT TOP...THEN INCREASE TO 70 KTS BY 12Z. INTERESTING THING IS THAT THE REVERSE SHEAR IS NOW MORE PROMINENT EARLIER IN THE EVENING...WHEN WINDS ARE NOT FORECAST TO BE AS STRONG...THEN AFTER MIDNIGHT WHEN WINDS START TO INCREASE THE REVERSE SHEAR DISAPPEARS. WITH THESE LINGERING QUESTIONS...AND AFTER TALKING TO OUR NEIGHBORS TO THE NORTH...HAVE DECIDED TO KEEP THE WATCH AS IS FOR NOW. HOPEFULLY...THE 12Z RUN WILL BE ENLIGHTENING FOR THE NEXT SHIFT. REGARDLESS...IT WILL GET WINDY ACROSS THE HIGHLIGHT AREAS LATE TONIGHT THROUGH AT LEAST MIDDAY SAT...BUT WHETHER WINDS WILL MEET WARNING CRITERIA IS STILL A QUESTION. 27 LONG TERM... .WINDY SATURDAY... MAIN CONCERN THIS FCST PERIOD IS WINDS FOR SATURDAY. STRONG DISTURBANCE WILL MOVE TO THE NORTH OF THE REGION DURING THIS DAY. STRONG GRADIENT WILL CAUSE STRONG WEST WINDS TO OCCUR DURING THE LATE MORNING AND AFTERNOON. STRONGEST WINDS WILL OCCUR OVER THE HIGHER ELEVATIONS OF THE MTNS AND ACROSS THE N SECTIONS OF THE PLAINS. AS FOR WIND HILITES...DID NOT MAKE ANY CHANGES ATTM AS SIMULATIONS SHOW THE STRONGEST FLOW WHERE CURRENT HILITES ARE IN PLACE. THERE IS A POSSIBILITY THAT WIND HILITES MAY NEED TO BE EXTENDED A BIT FARTHER SOUTH TO COVER PUEBLO...S EL PASO AND POSSIBLY KIOWA COUNTY...AND WILL MAKE THE DAY SHIFT AWARE OF THIS WHEN THEY ARRIVE LATER THIS MORNING. FLOW RAPIDLY DECREASES LATE IN THE DAY ACROSS MOST OF THE REGION EXCEPT THE FAR NE PLAINS. WINDS ARE FCST TO BE NEAR CALM BY 00Z SUNDAY OVER THE I-25 CORRIDOR REGION ON BOTH THE GFS AND NAM. WX AFTER SAT WILL BE RATHER TRANQUIL. A WEAK DISTURBANCE WILL MOVE ACROSS THE REGION DURING THE MID WEEK TIME FRAME...WED-ISH...BUT THIS SYSTEM APPEARS TO BE DRY WITH ONLY A SLIGHT COOLING. THE NEXT CHANCE OF ANY PRECIP WILL LIKELY BE NEXT WEEKEND. /34 AVIATION... VFR CONDITIONS EXPECTED AT THE THREE MAIN TAF SITES OF KCOS...KPUB AND KALS FOR THE NEXT 24 HRS. HOWEVER...WINDS ALOFT WILL STAY BRISK THROUGH THE DAY. 700 MB WINDS WILL BEGIN TO STRENGTHEN TONIGHT AFTER 06Z AND BE WNW 50 KTS...WITH 70 KTS AND POTENTIALLY HIGHER AT MTN TOP EXPECTED. THIS WILL CAUSE BLOWING SNOW AND SOME RESTRICTED VSBLY OVER THE PASSES LATE TONIGHT. && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR COZ077-078-083-084. HIGH WIND WATCH FROM LATE TONIGHT THROUGH SATURDAY AFTERNOON FOR COZ072-073-075-076-079>082. && $$ 31/23
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1041 AM MST FRI DEC 30 2011 .AVIATION... LIGHT SOUTHEAST WINDS WILL PERSIST THROUGH THE EARLY AFTERNOON FOR KCOS AND KPUB BEFORE WINDS INCREASE FROM THE SOUTH TO SOUTHWEST 10-15 KTS. WINDS AT KCOS WILL SHIFT AROUND FROM THE NORTH BY EARLY EVENING...WITH KPUB MAINTAINING A WEST WIND AROUND 10KTS THROUGH THE OVERNIGHT HOURS. AT THIS TIME...WITHOUT STRONG MTN WAVE PARAMETERS IN PLACE...THINK ANY LOW LEVEL WIND SHEAR WILL STAY TO THE WEST OF THE TAF SITES...BUT THIS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT...ESPECIALLY AT KCOS. EXPECT THAT WINDS WILL INCREASE ABRUPTLY AT KCOS AROUND 15Z ON SAT...AND AT 16-17Z AT KPUB WITH GUSTS TO AROUND 40 KTS. WINDS WILL REMAIN LIGHT AT KALS THROUGH THE PERIOD. GUSTY WINDS AT MTN TOP LEVELS ALONG WITH A ROUND OF SNOW TOMORROW MORNING WILL PRODUCE MTN OBSCURATIONS AT TIMES WITH BLOWING SNOW. WINDS AT MTN TOP LEVEL WILL BE SUSTAINED AROUND 50-60 KTS STARTING AROUND 06Z TONIGHT AND CONTINUING THROUGH TOMORROW. -KT && .PREV DISCUSSION... /ISSUED 350 AM MST FRI DEC 30 2011/ SHORT TERM... (TODAY AND TONIGHT) CURRENTLY...COLORADO WAS UNDER BRISK NW FLOW ALOFT...WITH SOME MTN WAVE CLOUDS SHOWING UP ON SATELLITE OVER THE SW MTS AND THE SANGRES. CONUS IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS SHOWED THAT THE NEXT UPPER SHORTWAVE THAT WILL AFFECT THE REGION BEGINNING LATER TONIGHT WAS JUST MOVING ONSHORE ACROSS THE PAC NW. CLOSER TO HOME...WINDS HAVE FINALLY DIMINISHED AND DECOUPLED FOR THE LOWER ELEVATIONS MAKING FOR A WIDE ARRAY OF SFC TEMPS. GENERALLY...AS OF 3 AM TEMPS HAD DROPPED INTO THE 30S TO UPPER 20S FOR MOST LOCATIONS...AND IN THE SINGLE DIGITS FOR THE SLV. TODAY...RELATIVELY QUIET AND MILD DAY FOR THE CWA TODAY UNDER SHORTWAVE RIDGING...WITH TEMPS WARMING INTO THE UPPER 40S AND 50S FOR THE PLAINS...AND IN THE 40S FOR THE SLV. WINDS ACROSS THE HIGHER ELEVATIONS WILL START TO PICK UP THROUGH LATE AFTN AS THE UPPER DISTURBANCE APPROACHES. TONIGHT...LATEST MODEL RUNS HAVE SEEMED TO SLOW EVERYTHING DOWN BY ABOUT 6 HRS OR SO...AND ARE NOW PLACING THE AXIS OF THE UPPER DISTURBANCE OVER W MONTANA AND IDAHO AT 06Z THIS EVE. THE PRES GRADIENT TIGHTENS AND THE H5 PLAN VIEW PAINTS THE STANDARD HIGH WIND SIGNATURE. MODEL CROSS SECTIONS DO SHOW ABOUT 55 TO 60 KTS AT MT TOP...THEN INCREASE TO 70 KTS BY 12Z. INTERESTING THING IS THAT THE REVERSE SHEAR IS NOW MORE PROMINENT EARLIER IN THE EVENING...WHEN WINDS ARE NOT FORECAST TO BE AS STRONG...THEN AFTER MIDNIGHT WHEN WINDS START TO INCREASE THE REVERSE SHEAR DISAPPEARS. WITH THESE LINGERING QUESTIONS...AND AFTER TALKING TO OUR NEIGHBORS TO THE NORTH...HAVE DECIDED TO KEEP THE WATCH AS IS FOR NOW. HOPEFULLY...THE 12Z RUN WILL BE ENLIGHTENING FOR THE NEXT SHIFT. REGARDLESS...IT WILL GET WINDY ACROSS THE HIGHLIGHT AREAS LATE TONIGHT THROUGH AT LEAST MIDDAY SAT...BUT WHETHER WINDS WILL MEET WARNING CRITERIA IS STILL A QUESTION. 27 LONG TERM... ..WINDY SATURDAY... MAIN CONCERN THIS FCST PERIOD IS WINDS FOR SATURDAY. STRONG DISTURBANCE WILL MOVE TO THE NORTH OF THE REGION DURING THIS DAY. STRONG GRADIENT WILL CAUSE STRONG WEST WINDS TO OCCUR DURING THE LATE MORNING AND AFTERNOON. STRONGEST WINDS WILL OCCUR OVER THE HIGHER ELEVATIONS OF THE MTNS AND ACROSS THE N SECTIONS OF THE PLAINS. AS FOR WIND HILITES...DID NOT MAKE ANY CHANGES ATTM AS SIMULATIONS SHOW THE STRONGEST FLOW WHERE CURRENT HILITES ARE IN PLACE. THERE IS A POSSIBILITY THAT WIND HILITES MAY NEED TO BE EXTENDED A BIT FARTHER SOUTH TO COVER PUEBLO...S EL PASO AND POSSIBLY KIOWA COUNTY...AND WILL MAKE THE DAY SHIFT AWARE OF THIS WHEN THEY ARRIVE LATER THIS MORNING. FLOW RAPIDLY DECREASES LATE IN THE DAY ACROSS MOST OF THE REGION EXCEPT THE FAR NE PLAINS. WINDS ARE FCST TO BE NEAR CALM BY 00Z SUNDAY OVER THE I-25 CORRIDOR REGION ON BOTH THE GFS AND NAM. WX AFTER SAT WILL BE RATHER TRANQUIL. A WEAK DISTURBANCE WILL MOVE ACROSS THE REGION DURING THE MID WEEK TIME FRAME...WED-ISH...BUT THIS SYSTEM APPEARS TO BE DRY WITH ONLY A SLIGHT COOLING. THE NEXT CHANCE OF ANY PRECIP WILL LIKELY BE NEXT WEEKEND. /34 AVIATION... VFR CONDITIONS EXPECTED AT THE THREE MAIN TAF SITES OF KCOS...KPUB AND KALS FOR THE NEXT 24 HRS. HOWEVER...WINDS ALOFT WILL STAY BRISK THROUGH THE DAY. 700 MB WINDS WILL BEGIN TO STRENGTHEN TONIGHT AFTER 06Z AND BE WNW 50 KTS...WITH 70 KTS AND POTENTIALLY HIGHER AT MTN TOP EXPECTED. THIS WILL CAUSE BLOWING SNOW AND SOME RESTRICTED VSBLY OVER THE PASSES LATE TONIGHT. && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR COZ077-078-083-084. HIGH WIND WATCH FROM LATE TONIGHT THROUGH SATURDAY AFTERNOON FOR COZ072-073-075-076-079>082. && $$ 31/23
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1200 PM CST FRI DEC 30 2011 .UPDATE... STARTING TO GET REPORTS OF THE RAIN TURNING NOW TO LIGHT SLEET/SNOW AT EDGEWOOD AND STANLEY IN OUR FAR NORTHWEST CWA. TEMPERATURES THERE HAD DROPPED TO THE FREEZING MARK BUT OBSERVERS MENTIONED THE SNOW/SLEET WAS MELTING UPON CONTACT WITH THE GROUND. HOWEVER BE CAREFUL ON BRIDGES/OVERPASSES AS THEY ARE COLDER. ELSEWHERE ACROSS THE DVN CWA LIGHT RAIN WAS STILL FALLING WITH TEMPERATURES IN THE MID 30S TO LOWER 40S. HAVE ALREADY UPDATED THE FORECAST TO REDUCE SNOW ACCUMULATIONS IN OUR FAR NORTHWEST TO LESS THAN ONE- HALF INCH. RADAR LOOPS SUGGEST PRECIPITATION RETURNS WERE DIMINISHING AS THE MOISTURE GETS CUT OFF DUE TO THE OCCLUDING STAGE OF THE CYCLONE THAT IS LOCATED EAST OF GENESEO IL IN HENRY COUNTY. LATEST RUC STILL INDICATES A TRANSITION TO A MIX OF LIGHT RAIN AND SNOW ACROSS OUR NORTH AS THE AFTERNOON PROGRESSES WITH PRECIPITATION ENDING IN OUR IL COUNTIES THIS EVENING. && .AVIATION... IFR CONDS IN -RA/BR/FG THROUGH THE AFTERNOON WITH THE RAIN CHANGING TO -SN/-IP AT KDBQ AND POSSIBLY KCID. PRECIPITATION TO END EARLY THIS EVENING THEN CIGS BECOMING MVFR. SKIES WILL BE CLEARING OVERNIGHT AS HIGH PRESSURE BUILDS INTO THE AREA. VFR CONDS EXPECTED ON SATURDAY. NORTHWEST WINDS GUSTING TO 20 KNOTS THIS AFTERNOON THEN WINDS DIMINISHING TO LESS THAN 10 KNOTS THIS EVENING. VARIABLE WINDS LESS THAN 5 KNOTS LATE TONIGHT THEN TURNING SOUTH AND INCREASING TO 15 TO 25 KNOTS BY SATURDAY AFTERNOON. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ HAASE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
415 PM EST FRI DEC 30 2011 .SYNOPSIS... LOW PRESSURE OVER THE GREAT LAKES WILL WEAKEN TONIGHT WITH REDEVELOPMENT OFF OF CAPE COD ON SATURDAY. THIS NEW LOW PRESSURE WILL TRACK EASTWARD THROUGH THE GULF OF MAINE AND THEN SOUTH OF NOVA SCOTIA BY SATURDAY EVENING. A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE REGION ON SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... SHORTWAVE TROUGH FLATTENING UPPER RIDGE ACROSS THE STATE IS PRODUCING AN AREA OF LIGHT SNOW SHOWERS ACROSS WESTERN MAINE THIS AFTERNOON. HRRR MODEL INDICATES AS THIS SHORTWAVE TROUGH MOVES ACROSS DOWNEAST LATE THIS AFTERNOON INTO THIS EVENING, A PERIOD OF SNOW SHOWERS CAN BE EXPECTED WITH ANY ACCUMULATION LESS THAN AN INCH. MODELS IN GOOD AGREEMENT WITH LOW PRESSURE OVER THE GREAT LAKES FILLING TONIGHT WITH REDEVELOPMENT JUST EAST OF CAPE COD BY SATURDAY AFTERNOON. THE LOW PRESSURE WILL THEN TRACK EASTWARD AND MOVE SOUTH OF NOVA SCOTIA BY SATURDAY NIGHT. WITH HIGH PRESSURE EAST OF THE REGION INSTEAD OF NORTH OF THE STATE, WARM ATLANTIC AIR IN THE LOWER LEVELS WILL BE ALLOWED TO FLOW NORTHWARD ACROSS THE FORECAST AREA PRODUCING ANOTHER WINTRY MIX FOR THE REGION. CRITICAL THICKNESS NOW INDICATING MORE MIX THAN SNOW SO HAVE REDUCE SNOW ACCUMULATION ACROSS CENTRAL AND NORTHERN SECTIONS BY AROUND AN INCH AND INCREASE ICE ACCUMULATIONS BY A TENTH OF AN INCH ACROSS CENTRAL PORTIONS. AT THIS TIME, EXPECT THE AXIS OF HEAVIEST ICE TO OCCUR 30 MILES ON EITHER SIDE OF A LINE FROM GREENVILLE TO HOULTON WHERE UP TO A QUARTER OF AN INCH MAY ACCUMULATE. MODELS ALSO INDICATING TEMPERATURES WILL BE SLOW TO RISE ACROSS DOWNEAST SO WILL EXTEND ADVISORY FROM 7 AM TO NOONTIME SATURDAY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... THINGS WILL BE WINDING DOWN SATURDAY NIGHT AS THE LOW MOVES OUT OF THE GULF OF MAINE AND SOUTH OF NOVA SCOTIA. THERE WILL BE SOME LINGERING FREEZING RAIN IN NORTHERN SECTIONS DURING THE EVENING BUT COLDER AIR WRAPPING AROUND THE DEPARTING SYSTEM WILL CHANGE THE PRECIPITATION TO ALL SNOW FROM NORTH TO SOUTH THROUGH THE NIGHT. SNOWFALL AMOUNTS WILL BE LIGHT...GENERALLY A DUSTING TO AROUND HALF AN INCH WITH ANOTHER TRACE OF ICE ACCUMULATION. HIGH PRESSURE WILL BRIEFLY BUILD IN SUNDAY BEFORE ANOTHER LOW PRESSURE SYSTEM MOVES BY TO OUR NORTH SUNDAY NIGHT AND MONDAY. THIS WILL BRING ANOTHER ROUND OF SNOW AND RAIN TO THE REGION. THE RAIN/SNOW LINE WILL BE SOUTH OF HOULTON AND MILLINOCKET WITH THE IMMEDIATE COAST ALL RAIN BY MONDAY AFTERNOON. EXPECT TEMPERATURES TO REACH INTO THE 30S DUE TO INCREASING SOUTH FLOW AHEAD OF THE SYSTEM...BUT A STRONG COLD FRONT WILL PUSH THROUGH THE REGION DURING THE DAY MONDAY USHERING IN MUCH COLDER AIR FOR THE WORK WEEK. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... COLDER AIR WILL FILTER INTO THE REGION FOR MONDAY NIGHT AND TUESDAY ACCOMPANIED BY MAINLY CLOUDY SKIES ALONG WITH SCATTERED SNOW SHOWERS AND FLURRIES DUE TO AN UPPER LEVEL TROUGH LINGERING IN THE REGION. PRECIPITATION WILL BE CONFINED MAINLY TO NORTHERN AREAS WHERE A FEW HEAVIER SNOW SHOWERS WILL BE POSSIBLE DUE TO BANDS SETTING UP OFF THE ST. LAWRENCE. HIGH PRESSURE WILL BRIEFLY MOVE IN FOR WEDNESDAY RESULTING IN MAINLY SUNNY SKIES AND DRY CONDITIONS REGION WIDE. HOWEVER TEMPERATURES WILL STRUGGLE TO MAKE IT OUT OF THE LOW TO MID TEENS NORTH WITH HIGHS DOWNEAST REACHING THE LOW 20S. HIGH PRESSURE WILL SLIDE OFF TO THE EAST THURSDAY AS THE NEXT UPPER LEVEL TROUGH APPROACHES THE EAST COAST RESULTING IN INCREASING CLOUDS ALONG WITH THE SLIGHT CHANCE FOR A FEW FLURRIES FOR THE END OF THE WEEK. AT THIS POINT ANY SURFACE CYCLOGENESIS ASSOCIATED WITH THIS TROUGH LOOKS TO TAKE PLACE TOO FAR SOUTH AND EAST TO AFFECT THE REGION WITH SIGNIFICANT PRECIPITATION. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... NEAR TERM: VFR CONDITIONS TONIGHT WILL LOWER TO IFR IN A WINTRY MIX ON SATURDAY. THERE MAY BE A BRIEF PERIOD OF MVFR/IFR IN SNOW AT KBGR AND KBHB BETWEEN 21Z-02Z AS AN AREA OF SNOW SHOWERS MOVES ACROSS DOWNEAST. SHORT TERM: IFR CONDITIONS IN SNOW AND RAIN THROUGH THE FIRST PART OF SATURDAY NIGHT. PERIODS OF FREEZING RAIN WILL BE POSSIBLE THROUGH 06Z SUNDAY. CONDITIONS WILL GRADUALLY IMPROVE AFTER MIDNIGHT AND EXPECT ALL TERMINALS TO BE VFR BY 12Z SUNDAY. A RETURN TO IFR COMES SUNDAY NIGHT AS SNOW SPREADS OVER THE REGION. IFR IN SNOW AND RAIN SUNDAY NIGHT AND MONDAY. BRIEF PERIODS OF MVFR/IFR CONDITIONS WILL BE POSSIBLE MONDAY NIGHT AND TUESDAY FOR THE NORTHERN SITES DUE TO LINGERING SCATTERED SNOW SHOWERS AND FLURRIES WITH VFR CONDITIONS PREDOMINATING FOR KBGR AND KBHB. HIGH PRESSURE WILL BUILD IN WEDNESDAY WITH VFR CONDITIONS EXPECTED FOR ALL SITES. && .MARINE... NEAR TERM: AS LOW PRESSURE MOVES THROUGH THE GULF OF MAINE, MINIMAL SCA CONDITIONS POSSIBLE OVER OUR OUTER WATERS ON SATURDAY. SHORT TERM: NO HEADLINES ANTICIPATED SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BRIEFLY BUILDS OVER THE WATERS. LOW PRESSURE WILL MOVE BY TO THE NORTH SUNDAY NIGHT AND MONDAY SO EXPECT WINDS AND SEAS TO INCREASE THROUGH THE PERIOD. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED WITH GALES A POSSIBILITY. WINDS AND SEAS WILL CONTINUE TO BE AT SCA LEVELS FOR MONDAY NIGHT AND TUESDAY. SEAS WILL DIMINISH WEDNESDAY BUT WINDS WILL CONTINUE TO REMAIN NEAR SCA LEVELS BEFORE DIMINISHING FOR WEDNESDAY NIGHT AND THURSDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SATURDAY FOR MEZ001>006-010. WINTER WEATHER ADVISORY FROM 1 AM TO NOON EST SATURDAY FOR MEZ011-015>017-031-032. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST SATURDAY FOR ANZ050- 051. && $$ NEAR TERM...FOSTER SHORT TERM...HASTINGS LONG TERM...FITZSIMMONS AVIATION...FOSTER MARINE...FOSTER/HASTINGS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
350 PM EST FRI DEC 30 2011 .SYNOPSIS... LOW PRESSURE OVER THE GREAT LAKES WILL WEAKEN TONIGHT WITH REDEVELOPMENT OFF OF CAPE COD ON SATURDAY. THIS NEW LOW PRESSURE WILL TRACK EASTWARD THROUGH THE GULF OF MAINE AND THEN SOUTH OF NOVA SCOTIA BY SATURDAY EVENING. A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE REGION ON SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... SHORTWAVE TROUGH FLATTENING UPPER RIDGE ACROSS THE STATE IS PRODUCING AN AREA OF LIGHT SNOW SHOWERS ACROSS WESTERN MAINE THIS AFTERNOON. HRRR MODEL INDICATES AS THIS SHORTWAVE TROUGH MOVES ACROSS DOWNEAST LATE THIS AFTERNOON INTO THIS EVENING, A PERIOD OF SNOW SHOWERS CAN BE EXPECTED WITH ANY ACCUMULATION LESS THAN AN INCH. MODELS IN GOOD AGREEMENT WITH LOW PRESSURE OVER THE GREAT LAKES FILLING TONIGHT WITH REDEVELOPMENT JUST EAST OF CAPE COD BY SATURDAY AFTERNOON. THE LOW PRESSURE WILL THEN TRACK EASTWARD AND MOVE SOUTH OF NOVA SCOTIA BY SATURDAY NIGHT. AS HAS BEEN THE CASE THIS WINTER, A LOW PRESSURE TRACKING SOUTH OF THE STATE WILL STILL ALLOW FOR WARM AIR TO RIDE SOUTHWARD IN ADVANCE OF THE LOW PRESSURE. THIS WARM AIR ALOFT WILL PRODUCE ANOTHER WINTRY MIX FOR THE FORECAST AREA. CRITICAL THICKNESS NOW INDICATING MORE MIX THAN SNOW SO HAVE REDUCE SNOW ACCUMULATION ACROSS CENTRAL AND NORTHERN SECTIONS BY AROUND AN INCH AND INCREASE ICE ACCUMULATIONS BY A TENTH OF AN INCH ACROSS CENTRAL PORTIONS. AT THIS TIME, EXPECT THE AXIS OF HEAVIEST ICE TO OCCUR 30 MILES ON EITHER SIDE OF A LINE FROM GREENVILLE TO HOULTON WHERE UP TO A QUARTER OF AN INCH MAY ACCUMULATE. MODELS ALSO INDICATING TEMPERATURES WILL BE SLOW TO RISE ACROSS DOWNEAST SO WILL EXTEND ADVISORY FROM 7 AM TO NOONTIME SATURDAY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... THINGS WILL BE WINDING DOWN SATURDAY NIGHT AS THE LOW MOVES OUT OF THE GULF OF MAINE AND SOUTH OF NOVA SCOTIA. THERE WILL BE SOME LINGERING FREEZING RAIN IN NORTHERN SECTIONS DURING THE EVENING BUT COLDER AIR WRAPPING AROUND THE DEPARTING SYSTEM WILL CHANGE THE PRECIPITATION TO ALL SNOW FROM NORTH TO SOUTH THROUGH THE NIGHT. SNOWFALL AMOUNTS WILL BE LIGHT...GENERALLY A DUSTING TO AROUND HALF AN INCH WITH ANOTHER TRACE OF ICE ACCUMULATION. HIGH PRESSURE WILL BRIEFLY BUILD IN SUNDAY BEFORE ANOTHER LOW PRESSURE SYSTEM MOVES BY TO OUR NORTH SUNDAY NIGHT AND MONDAY. THIS WILL BRING ANOTHER ROUND OF SNOW AND RAIN TO THE REGION. THE RAIN/SNOW LINE WILL BE SOUTH OF HOULTON AND MILLINOCKET WITH THE IMMEDIATE COAST ALL RAIN BY MONDAY AFTERNOON. EXPECT TEMPERATURES TO REACH INTO THE 30S DUE TO INCREASING SOUTH FLOW AHEAD OF THE SYSTEM...BUT A STRONG COLD FRONT WILL PUSH THROUGH THE REGION DURING THE DAY MONDAY USHERING IN MUCH COLDER AIR FOR THE WORK WEEK. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... COLDER AIR WILL FILTER INTO THE REGION FOR MONDAY NIGHT AND TUESDAY ACCOMPANIED BY MAINLY CLOUDY SKIES ALONG WITH SCATTERED SNOW SHOWERS AND FLURRIES DUE TO AN UPPER LEVEL TROUGH LINGERING IN THE REGION. PRECIPITATION WILL BE CONFINED MAINLY TO NORTHERN AREAS WHERE A FEW HEAVIER SNOW SHOWERS WILL BE POSSIBLE DUE TO BANDS SETTING UP OFF THE ST. LAWRENCE. HIGH PRESSURE WILL BRIEFLY MOVE IN FOR WEDNESDAY RESULTING IN MAINLY SUNNY SKIES AND DRY CONDITIONS REGION WIDE. HOWEVER TEMPERATURES WILL STRUGGLE TO MAKE IT OUT OF THE LOW TO MID TEENS NORTH WITH HIGHS DOWNEAST REACHING THE LOW 20S. HIGH PRESSURE WILL SLIDE OFF TO THE EAST THURSDAY AS THE NEXT UPPER LEVEL TROUGH APPROACHES THE EAST COAST RESULTING IN INCREASING CLOUDS ALONG WITH THE SLIGHT CHANCE FOR A FEW FLURRIES FOR THE END OF THE WEEK. AT THIS POINT ANY SURFACE CYCLOGENESIS ASSOCIATED WITH THIS TROUGH LOOKS TO TAKE PLACE TOO FAR SOUTH AND EAST TO AFFECT THE REGION WITH SIGNIFICANT PRECIPITATION. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... NEAR TERM: VFR CONDITIONS TONIGHT WILL LOWER TO IFR IN A WINTRY MIX ON SATURDAY. THERE MAY BE A BRIEF PERIOD OF MVFR/IFR IN SNOW AT KBGR AND KBHB BETWEEN 21Z-02Z AS AN AREA OF SNOW SHOWERS MOVES ACROSS DOWNEAST. SHORT TERM: IFR CONDITIONS IN SNOW AND RAIN THROUGH THE FIRST PART OF SATURDAY NIGHT. PERIODS OF FREEZING RAIN WILL BE POSSIBLE THROUGH 06Z SUNDAY. CONDITIONS WILL GRADUALLY IMPROVE AFTER MIDNIGHT AND EXPECT ALL TERMINALS TO BE VFR BY 12Z SUNDAY. A RETURN TO IFR COMES SUNDAY NIGHT AS SNOW SPREADS OVER THE REGION. IFR IN SNOW AND RAIN SUNDAY NIGHT AND MONDAY. BRIEF PERIODS OF MVFR/IFR CONDITIONS WILL BE POSSIBLE MONDAY NIGHT AND TUESDAY FOR THE NORTHERN SITES DUE TO LINGERING SCATTERED SNOW SHOWERS AND FLURRIES WITH VFR CONDITIONS PREDOMINATING FOR KBGR AND KBHB. HIGH PRESSURE WILL BUILD IN WEDNESDAY WITH VFR CONDITIONS EXPECTED FOR ALL SITES. && .MARINE... NEAR TERM: AS LOW PRESSURE MOVES THROUGH THE GULF OF MAINE, MINIMAL SCA CONDITIONS POSSIBLE OVER OUR OUTER WATERS ON SATURDAY. SHORT TERM: NO HEADLINES ANTICIPATED SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BRIEFLY BUILDS OVER THE WATERS. LOW PRESSURE WILL MOVE BY TO THE NORTH SUNDAY NIGHT AND MONDAY SO EXPECT WINDS AND SEAS TO INCREASE THROUGH THE PERIOD. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED WITH GALES A POSSIBILITY. WINDS AND SEAS WILL CONTINUE TO BE AT SCA LEVELS FOR MONDAY NIGHT AND TUESDAY. SEAS WILL DIMINISH WEDNESDAY BUT WINDS WILL CONTINUE TO REMAIN NEAR SCA LEVELS BEFORE DIMINISHING FOR WEDNESDAY NIGHT AND THURSDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SATURDAY FOR MEZ001>006-010. WINTER WEATHER ADVISORY FROM 1 AM TO NOON EST SATURDAY FOR MEZ011-015>017-031-032. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST SATURDAY FOR ANZ050- 051. && $$ NEAR TERM...FOSTER SHORT TERM...HASTINGS LONG TERM...FITZSIMMONS AVIATION...FOSTER MARINE...FOSTER/HASTINGS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1254 PM EST FRI DEC 30 2011 UPDATED AVIATION DISCUSSION FOR 18Z TAFS .UPDATE... NOT A WHOLE LOT OF WEATHER OF SIGNIFICANCE TODAY BUT STILL A TRICKY UPDATE. CURRENTLY...LOW PRESSURE SYSTEM IS BRINGING MIXED PRECIPITATION TO SOUTHERN PORTIONS OF WISCONSIN...BUT THIS SYSTEM WILL REMAIN TO THE SOUTH OF THE CWA THROUGH THE DAY. LOW PRESSURE TROUGH EXTENDS NORTH OF THE SFC LOW ACROSS CNTRL UPR MI. CONDITIONS ARE MAINLY DRY THOUGH WITH EVEN SOME SUNSHINE THROUGH HIGHER CLOUDS OVR CNTRL CWA THIS MORNING. LOW-LEVELS REMAIN VERY SATURATED OVR EASTERN CWA AND ALONG WITH LOW CLOUDS AND FOG THERE IS LIKELY SOME FZDZ/MIST OCCURRING AS WELL. LK EFFECT IS RESTRICTED TO CNTRL AND EASTERN LK SUPERIOR BASED ON VISIBLE SATELLITE. AS THE LOW TO THE SOUTH HEADS INTO LOWER MICHIGAN LATER TODAY... EXPECT WINDS OVR MOST OF LK SUPERIOR INTO UPR MI TO BECOME MORE NORTHERLY. THIS SHOULD ALLOW FOR SOME LK EFFECT SNOW SHOWERS TO WORK ONSHORE OVR KEWEENAW AND ALSO IN NCNTRL UPR MI. TEMPS AT INVERSION TOP AROUND 900MB ONLY STRUGGLE TO REACH -7C...SO FZDZ COULD OCCUR. SEEMS LIKE THERE IS ENOUGH DRY AIR IN BLYR BASED ON SFC DEWPNT DEPRESSIONS UP TO 4F AT KCMX/KP59 TO LIMIT THAT RISK THOUGH...AND PROBABLY WOULD JUST SEE FLURRIES IF SNOW SHOWERS CAN NOT REALLY ADVECT ONSHORE. TEMPS TODAY SHOULD REACH INTO THE 27-32 RANGE...COLDEST IN THE CNTRL CWA WHERE THE CLEARING LATE LAST NIGHT ALLOWED LOWS TO DIP TOWARD 10 ABOVE. ALL LIGHT PRECIPITATION WILL CEASE OVERNIGHT TONIGHT AS WINDS BECOME MORE SOUTHERLY IN ADVANCE OF STRONGER LOW PRESSURE SYSTEM MOVING INTO THE PLAINS. && .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER THE GRT LKS BTWN LO AMPLITUDE RDGING OVER THE W AND A TROF N JUST OFF THE E COAST. SHRTWV RESPONSIBLE FOR SN ON THU IS PUSHING EWD TOWARD SE ONTARIO...BUT WEAK SFC-H85 TROF REMAINS OVER ERN UPR MI. BUT WITH DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE/DRYING ALF IN THE WAKE OF THE SHRTWV...THE PCPN OVER THE CWA HAS PRETTY MUCH ENDED. THE MQT 88D DOES SHOW HIER RADAR RETURNS OVER ECNTRL LK SUP NEAR WEAK SFC LO CENTER. 00Z INL RAOB SHOWS SHARP INVRN BASE NEAR H875 WITH TEMP JUST BLO THE INVRN DOWN TO -14C...LO ENUF TO SUPPORT LES. ALTHOUGH THE 00Z INL RAOB INDICATES MODEST DRYING IN THE SUB INVRN LYR...SKIES ARE GENERALLY CLDY AT MOST LOCATIONS FM THE MN ARROWHEAD SEWD THRU UPR MI...BUT SOME BREAKS IN THE CLDS ARE EVIDENT. FARTHER TO THE W/SW IN MN/WI...SKIES ARE MOCLR CLOSER TO WEAK SFC RDG AXIS ASSOCIATED WITH INCOMING SHRTWV RDG MOVING E THRU MN. ANOTHER PAIR OF SHRTWVS ARE NOTED IN THE NRN/CNTRL PLAINS...BUT THESE APPEAR TO BE DIGGING TO THE SE. MUCH FARTHER TO THE W...A STRONG SHRTWV IS APRCHG THE PAC NW. UPSTREAM HI TEMPS YDAY SUG MAX TEMPS WL GENERALLY BE ARND 30. && .DISCUSSION... MAIN FCST CONCERNS THIS PACKAGE SHIFT TO POTENTIAL SN EVENT ON NEW YEARS DAY/MON RELATED TO SHRTWV NOW APRCHG THE PAC NW. TDAY...LOOKS LIKE A RELATIVELY QUIET DAY ON TAP WITH WEAK HGT RISES/DRYING ALF IN THE WAKE OF DEPARTING SHRTWV. SHRTWV COMPLEX IN THE PLAINS IS FCST TO CONSOLIDATE IN THE LOWER GRT LKS...WITH ACCOMPANYING DEEP LYR QVECTOR CNVGC/PCPN PASSING S OF UPR MI. FCST SDNGS SHOW INVRN BASE SINKING TO H9-925 OVER THE CWA IN THE AFTN... WITH INVRN BASE TEMPS NO LOWER THAN ABOUT -8C. CONSIDERING THE WEAK SFC WINDS FCST THAT WOULD NOT SUPPORT ORGANIZATION OF LES BANDS...THE MARGINAL NATURE OF THE CHILL/DGZ ABV THE SUB INVRN LYR...AND SOME LLVL DRYING...SUSPECT THERE WL BE LTL IN THE WAKE OF LES. BUT SINCE THE 00Z INL RAOB DID SHOW -14C AIR AT THE H875 INVRN BASE AND THE GFS/NAM MODEL ANALYSIS WAS ABOUT 3C TOO WARM AT THAT SITE...WL MAINTAIN GOING POPS NEAR LK SUP...ESPECIALLY E OFMQT WHERE WEAK SFC TROF IS FCST TO PERSIST THRU THE DAY. ALSO ADDED A MENTION OF FZDZ IN THIS AREA WHERE THE LLVL MSTR REMAINS A BIT MORE RESILIENT AND THE LLVL TEMPS ARE NOT LIKELY TO BE AS LO AS OBSVD AT INL. TNGT...SHRTWV RDGING WL BE DOMINATING WITH WEAK SFC HI PRES RDG AXIS BLDG OVHD. MAINTAINED LO CHC POPS IN THE EVNG OVER THE E WHERE THE SFC LO PRES TROF WL LINGER WHILE SLOWLY WEAKENING WITH TIME. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR SCNTRL WHERE SKIES WL TREND MOCLR UNDER LIGHT SFC ACYC FLOW. SAT...AS SHRTWV COMPLEX NOW MOVING TOWARD THE PAC NW SPLITS AND DEEPENS TROFS IN SCNTRL CAN AND THE CENTRAL PLAINS...INCRSG SW FLOW WL DVLP OVER THE UPR LKS AND RETURN DEEPER MSTR TO THE UPR LKS. WITH INITIAL LLVL DRY AIR...RESTRICTED POPS MAINLY ON SAT AFT TO THE NW HALF OF THE CWA WHERE GUIDANCE SHOWS DEEPER MOISTENING ON CYC SIDE OF UPR JET AXIS ROTATING NEWD TOWARD THE UPR LKS BY 00Z SUN. SFC TEMPS ARE PROGGED TO RISE AOA 32 IN THE AFTN AS H85 TEMPS RISE TO ARND 0C...BUT NAM/SREF FCST WBLB ZERO HGT BLO 500 AGL WITH LINGERING LLVL DRY AIR SUG VERY LTL CHC RA MAY BE MIXED WITH THE PCPN AT THE ONSET. SAT NGT INTO MON...MODELS HAVE BEGUN TO CONVERGE ON A SCENARIO SHOWING A DEEPENING UPR TROF/SFC LO AS SEPARATE SHRTWVS IN SCNTRL CAN AND THE CENTRAL PLAINS PHASE. THE GFS IS MOST AGGRESSIVE AT DEEPENING A CLOSED LO...SHOWING A 984MB SFC LO OVER NRN LK MI BY 12Z SUN. PER NCEP DISCUSSION...USED A BLEND OF THE INTERMEDIATE STRENGTH 00Z NAM/00Z CNDN/21Z SREF/12Z ECMWF FOR FCST PREPARATION. THESE MODELS SHOW SFC LO TRACKING ACRS LK SUP/SRN ONTARIO SAT NGT AND DRAWING ENUF LLVL MSTR OVER UPR MI TO SUPPORT LIKELY POPS UNDER UPR DVGC ON CYC SIDE OF JET AXIS WHERE 12HR H5 FALLS APRCH 200M. WITH THE ARRIVAL OF MORE LLVL MSTR OVER THE E...FCST THKNS/WBLB ZERO HGT SUPPORT AT LEAST A MIX WITH RA IN THAT AREA. ONCE THE LO SHIFTS TO THE NE LATE SAT NGT/SUN...STRONG NW WINDS WITH H85 WINDS AOA 50KT ADVECT MUCH COLDER AIR INTO THE UPR LKS...SETTING UP A LK ENHANCED SN EVENT WITH FCST SDNGS SHOWING DEEP MSTR UNDER LO HGTS AND OMEGA WITHIN THE LOWERING DGZ AND SHARP CYC FLOW. GUSTY NW WINDS WL ALSO RESULT IN CONSIDERABLE BLSN. THIS LK ENHANCED SN WL THEN PERSIST INTO MON BEFORE THE DEEPER MSTR SLOWLY EXITS AND PCPN TENDS TOWARD PURE LES BY MON NGT. CONSIDERED DOING A WATCH FOR THE NW WIND SN BELTS...ESPECIALLY OVER THE W WHERE MOST RECENT NCEP GUIDANCE SHOWS UP TO A FOOT OF SN THRU 12Z MON. BUT SINCE THE BULK OF THE MOST SGNFT WX WL OCCUR IN THE 5TH TO 7TH PERIODS...OPTED TO ISSUE AN SPS TO COVER THIS POTENTIAL WINTER STORM. EXTENDED...LATEST GUIDANCE IN GOOD AGREEMENT SHOWING DEEP UPR TROF GIVING WAY TO A MORE ZONAL FLOW AFT MID WEEK WITH A WARMING TREND. DID LOWER FCST MIN TEMPS A FEW DEGREES FM THE ALLBLEND FCST OVER THE INTERIOR W HALF ON MON NGT GIVEN ARRIVAL OF SFC RDG AXIS/LGT WINDS/PWAT AS LO AS 0.1 INCH. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... VARIABLE WINDS OVER THE AREA ARE MAKING FOR A DIFFICULT AVIATION FCST THIS AFTN. EXPECT MOST SITES TO REMAIN WITH/OR DEVELOP MVFR CIGS THROUGH THIS EVENING AS WINDS BECOME MORE NORTHERLY OFF LK SUPERIOR. COULD BE SOME LGT SNOW SHOWERS/FLURRIES LATE THIS AFTN INTO THE EVENING BUT ANY VSBY REDUCTION WOULD BE BRIEF. ONCE CLEARING OCCURS LATE TONIGHT...MAY SEE FOG DEVELOP AT KCMX. FAIRLY QUIET CONDITIONS WILL SETUP ON SATURDAY WITH JUST SOME HIGHER CLOUDS STREAMING IN FM THE WEST AHEAD OF STRONG SYSTEM THAT IS FORECAST TO BLAST INTO THE UPPER GREAT LAKES SATURDAY NIGHT. OUTLOOK...DUE TO STRONG WINDS/HEAVY LK EFFECT SNOW...FLYING CONDITIONS ARE EXPECTED TO BECOME VERY POOR LATE SATURDAY NIGHT INTO NEW YEARS DAY. ADVERSE CONDITIONS...POSSIBLY AT OR BLO AIRPORT MINS...SHOULD CONTINUE INTO MONDAY. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... WINDS WILL DIMINISH TODAY AS LOW PRESSURE TROUGH LINGERS OVER LAKE SUPERIOR. A WEAK RIDGE WILL THEN SLIDE ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END GALES ARE LOOKING LIKELY FROM THIS SYSTEM...BEGINNING ON NEW YEARS DAY AND CONTINUING THROUGH MONDAY AS COLDER AIR PLOWS INTO THE GREAT LAKES. HEAVY FREEZING SPRAY ALSO MAY OCCUR SUNDAY NIGHT INTO MONDAY. GALE AND HEAVY FREEZING SPRAY WATCHES WILL LIKELY NEED TO BE ISSUED IN THE NEXT COUPLE DAYS. WINDS DIMINISH SIGNIFICANTLY BY NEXT TUESDAY WITH ARRIVAL OF HIGH PRESSURE RIDGE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SYNOPSIS...KC DISCUSSION...KC AVIATION...JLA MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1112 AM EST FRI DEC 30 2011 .UPDATE... NOT A WHOLE LOT OF WEATHER OF SIGNIFICANCE TODAY BUT STILL A TRICKY UPDATE. CURRENTLY...LOW PRESSURE SYSTEM IS BRINGING MIXED PRECIPITATION TO SOUTHERN PORTIONS OF WISCONSIN...BUT THIS SYSTEM WILL REMAIN TO THE SOUTH OF THE CWA THROUGH THE DAY. LOW PRESSURE TROUGH EXTENDS NORTH OF THE SFC LOW ACROSS CNTRL UPR MI. CONDITIONS ARE MAINLY DRY THOUGH WITH EVEN SOME SUNSHINE THROUGH HIGHER CLOUDS OVR CNTRL CWA THIS MORNING. LOW-LEVELS REMAIN VERY SATURATED OVR EASTERN CWA AND ALONG WITH LOW CLOUDS AND FOG THERE IS LIKELY SOME FZDZ/MIST OCCURRING AS WELL. LK EFFECT IS RESTRICTED TO CNTRL AND EASTERN LK SUPERIOR BASED ON VISIBLE SATELLITE. AS THE LOW TO THE SOUTH HEADS INTO LOWER MICHIGAN LATER TODAY... EXPECT WINDS OVR MOST OF LK SUPERIOR INTO UPR MI TO BECOME MORE NORTHERLY. THIS SHOULD ALLOW FOR SOME LK EFFECT SNOW SHOWERS TO WORK ONSHORE OVR KEWEENAW AND ALSO IN NCNTRL UPR MI. TEMPS AT INVERSION TOP AROUND 900MB ONLY STRUGGLE TO REACH -7C...SO FZDZ COULD OCCUR. SEEMS LIKE THERE IS ENOUGH DRY AIR IN BLYR BASED ON SFC DEWPNT DEPRESSIONS UP TO 4F AT KCMX/KP59 TO LIMIT THAT RISK THOUGH...AND PROBABLY WOULD JUST SEE FLURRIES IF SNOW SHOWERS CAN NOT REALLY ADVECT ONSHORE. TEMPS TODAY SHOULD REACH INTO THE 27-32 RANGE...COLDEST IN THE CNTRL CWA WHERE THE CLEARING LATE LAST NIGHT ALLOWED LOWS TO DIP TOWARD 10 ABOVE. ALL LIGHT PRECIPITATION WILL CEASE OVERNIGHT TONIGHT AS WINDS BECOME MORE SOUTHERLY IN ADVANCE OF STRONGER LOW PRESSURE SYSTEM MOVING INTO THE PLAINS. && PREV DISCUSSION...ISSUED AT 636 AM EST FRI DEC 30 2011... .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER THE GRT LKS BTWN LO AMPLITUDE RDGING OVER THE W AND A TROF N JUST OFF THE E COAST. SHRTWV RESPONSIBLE FOR SN ON THU IS PUSHING EWD TOWARD SE ONTARIO...BUT WEAK SFC-H85 TROF REMAINS OVER ERN UPR MI. BUT WITH DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE/DRYING ALF IN THE WAKE OF THE SHRTWV...THE PCPN OVER THE CWA HAS PRETTY MUCH ENDED. THE MQT 88D DOES SHOW HIER RADAR RETURNS OVER ECNTRL LK SUP NEAR WEAK SFC LO CENTER. 00Z INL RAOB SHOWS SHARP INVRN BASE NEAR H875 WITH TEMP JUST BLO THE INVRN DOWN TO -14C...LO ENUF TO SUPPORT LES. ALTHOUGH THE 00Z INL RAOB INDICATES MODEST DRYING IN THE SUB INVRN LYR...SKIES ARE GENERALLY CLDY AT MOST LOCATIONS FM THE MN ARROWHEAD SEWD THRU UPR MI...BUT SOME BREAKS IN THE CLDS ARE EVIDENT. FARTHER TO THE W/SW IN MN/WI...SKIES ARE MOCLR CLOSER TO WEAK SFC RDG AXIS ASSOCIATED WITH INCOMING SHRTWV RDG MOVING E THRU MN. ANOTHER PAIR OF SHRTWVS ARE NOTED IN THE NRN/CNTRL PLAINS...BUT THESE APPEAR TO BE DIGGING TO THE SE. MUCH FARTHER TO THE W...A STRONG SHRTWV IS APRCHG THE PAC NW. UPSTREAM HI TEMPS YDAY SUG MAX TEMPS WL GENERALLY BE ARND 30. && .DISCUSSION... MAIN FCST CONCERNS THIS PACKAGE SHIFT TO POTENTIAL SN EVENT ON NEW YEARS DAY/MON RELATED TO SHRTWV NOW APRCHG THE PAC NW. TDAY...LOOKS LIKE A RELATIVELY QUIET DAY ON TAP WITH WEAK HGT RISES/DRYING ALF IN THE WAKE OF DEPARTING SHRTWV. SHRTWV COMPLEX IN THE PLAINS IS FCST TO CONSOLIDATE IN THE LOWER GRT LKS...WITH ACCOMPANYING DEEP LYR QVECTOR CNVGC/PCPN PASSING S OF UPR MI. FCST SDNGS SHOW INVRN BASE SINKING TO H9-925 OVER THE CWA IN THE AFTN... WITH INVRN BASE TEMPS NO LOWER THAN ABOUT -8C. CONSIDERING THE WEAK SFC WINDS FCST THAT WOULD NOT SUPPORT ORGANIZATION OF LES BANDS...THE MARGINAL NATURE OF THE CHILL/DGZ ABV THE SUB INVRN LYR...AND SOME LLVL DRYING...SUSPECT THERE WL BE LTL IN THE WAKE OF LES. BUT SINCE THE 00Z INL RAOB DID SHOW -14C AIR AT THE H875 INVRN BASE AND THE GFS/NAM MODEL ANALYSIS WAS ABOUT 3C TOO WARM AT THAT SITE...WL MAINTAIN GOING POPS NEAR LK SUP...ESPECIALLY E OFMQT WHERE WEAK SFC TROF IS FCST TO PERSIST THRU THE DAY. ALSO ADDED A MENTION OF FZDZ IN THIS AREA WHERE THE LLVL MSTR REMAINS A BIT MORE RESILIENT AND THE LLVL TEMPS ARE NOT LIKELY TO BE AS LO AS OBSVD AT INL. TNGT...SHRTWV RDGING WL BE DOMINATING WITH WEAK SFC HI PRES RDG AXIS BLDG OVHD. MAINTAINED LO CHC POPS IN THE EVNG OVER THE E WHERE THE SFC LO PRES TROF WL LINGER WHILE SLOWLY WEAKENING WITH TIME. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR SCNTRL WHERE SKIES WL TREND MOCLR UNDER LIGHT SFC ACYC FLOW. SAT...AS SHRTWV COMPLEX NOW MOVING TOWARD THE PAC NW SPLITS AND DEEPENS TROFS IN SCNTRL CAN AND THE CENTRAL PLAINS...INCRSG SW FLOW WL DVLP OVER THE UPR LKS AND RETURN DEEPER MSTR TO THE UPR LKS. WITH INITIAL LLVL DRY AIR...RESTRICTED POPS MAINLY ON SAT AFT TO THE NW HALF OF THE CWA WHERE GUIDANCE SHOWS DEEPER MOISTENING ON CYC SIDE OF UPR JET AXIS ROTATING NEWD TOWARD THE UPR LKS BY 00Z SUN. SFC TEMPS ARE PROGGED TO RISE AOA 32 IN THE AFTN AS H85 TEMPS RISE TO ARND 0C...BUT NAM/SREF FCST WBLB ZERO HGT BLO 500 AGL WITH LINGERING LLVL DRY AIR SUG VERY LTL CHC RA MAY BE MIXED WITH THE PCPN AT THE ONSET. SAT NGT INTO MON...MODELS HAVE BEGUN TO CONVERGE ON A SCENARIO SHOWING A DEEPENING UPR TROF/SFC LO AS SEPARATE SHRTWVS IN SCNTRL CAN AND THE CENTRAL PLAINS PHASE. THE GFS IS MOST AGGRESSIVE AT DEEPENING A CLOSED LO...SHOWING A 984MB SFC LO OVER NRN LK MI BY 12Z SUN. PER NCEP DISCUSSION...USED A BLEND OF THE INTERMEDIATE STRENGTH 00Z NAM/00Z CNDN/21Z SREF/12Z ECMWF FOR FCST PREPARATION. THESE MODELS SHOW SFC LO TRACKING ACRS LK SUP/SRN ONTARIO SAT NGT AND DRAWING ENUF LLVL MSTR OVER UPR MI TO SUPPORT LIKELY POPS UNDER UPR DVGC ON CYC SIDE OF JET AXIS WHERE 12HR H5 FALLS APRCH 200M. WITH THE ARRIVAL OF MORE LLVL MSTR OVER THE E...FCST THKNS/WBLB ZERO HGT SUPPORT AT LEAST A MIX WITH RA IN THAT AREA. ONCE THE LO SHIFTS TO THE NE LATE SAT NGT/SUN...STRONG NW WINDS WITH H85 WINDS AOA 50KT ADVECT MUCH COLDER AIR INTO THE UPR LKS...SETTING UP A LK ENHANCED SN EVENT WITH FCST SDNGS SHOWING DEEP MSTR UNDER LO HGTS AND OMEGA WITHIN THE LOWERING DGZ AND SHARP CYC FLOW. GUSTY NW WINDS WL ALSO RESULT IN CONSIDERABLE BLSN. THIS LK ENHANCED SN WL THEN PERSIST INTO MON BEFORE THE DEEPER MSTR SLOWLY EXITS AND PCPN TENDS TOWARD PURE LES BY MON NGT. CONSIDERED DOING A WATCH FOR THE NW WIND SN BELTS...ESPECIALLY OVER THE W WHERE MOST RECENT NCEP GUIDANCE SHOWS UP TO A FOOT OF SN THRU 12Z MON. BUT SINCE THE BULK OF THE MOST SGNFT WX WL OCCUR IN THE 5TH TO 7TH PERIODS...OPTED TO ISSUE AN SPS TO COVER THIS POTENTIAL WINTER STORM. EXTENDED...LATEST GUIDANCE IN GOOD AGREEMENT SHOWING DEEP UPR TROF GIVING WAY TO A MORE ZONAL FLOW AFT MID WEEK WITH A WARMING TREND. DID LOWER FCST MIN TEMPS A FEW DEGREES FM THE ALLBLEND FCST OVER THE INTERIOR W HALF ON MON NGT GIVEN ARRIVAL OF SFC RDG AXIS/LGT WINDS/PWAT AS LO AS 0.1 INCH. && .AVIATION /FOR THE 12Z TAF ISSUANCE/... LIGHT LOW-LEVEL WIND REGIME THRU THIS FCST PERIOD SUGGESTS CONDITIONS PROBABLY WILL NOT CHANGE MUCH AT KIWD/KCMX/KSAW. SO...GIVEN THE LOW-LEVEL MOISTURE OVER THE AREA AND GENERAL MVFR CIGS...MVFR CIGS WILL LIKELY PREVAIL THRU THE FCST PERIOD. HOWEVER...THERE MAY BE SOME PERIODS WHERE CLOUDS SCATTER OUT OR CIGS RISE TO VFR AS INDICATED BY CURRENT REGIONAL SFC OBS AND SATELLITE IMAGERY. FG AS SAW SHOULD BURN OFF THIS MORNING AS SURFACE TEMPS INCREASE. FG MAY FORM AT CMX TONIGHT GIVEN ABUNDANT LOW LEVEL MOISTURE...IF CLOUDS CAN CLEAR OUT ENOUGH. THE EXACT TIMING IS STILL IN QUESTION. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... WINDS WILL DIMINISH TODAY AS LOW PRESSURE TROUGH LINGERS OVER LAKE SUPERIOR. A WEAK RIDGE WILL THEN SLIDE ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END GALES ARE LOOKING LIKELY FROM THIS SYSTEM...BEGINNING ON NEW YEARS DAY AND CONTINUING THROUGH MONDAY AS COLDER AIR PLOWS INTO THE GREAT LAKES. HEAVY FREEZING SPRAY ALSO MAY OCCUR SUNDAY NIGHT INTO MONDAY. GALE AND HEAVY FREEZING SPRAY WATCHES WILL LIKELY NEED TO BE ISSUED IN THE NEXT COUPLE DAYS. WINDS DIMINISH SIGNIFICANTLY BY NEXT TUESDAY WITH ARRIVAL OF HIGH PRESSURE RIDGE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SYNOPSIS...KC DISCUSSION...KC AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
930 AM MST FRI DEC 30 2011 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY... SENT AN UPDATE THIS MORNING TO ADJUST...ADD...AND FINE TUNE THE PLACEMENT AND TIMING OF SPRINKLES AND LIGHT RAIN ACCORDING TO CURRENT RADAR TRENDS AND HRRR MODEL DEPICTIONS LEADING INTO THE TONIGHT TIME FRAME. IT LOOKS LIKE THERE COULD BE SOME SCATTERED SPRINKLES AS THE SYSTEM GET ORGANIZED AHEAD OF THE LINEAR PRECIPITATION FEATURE TONIGHT. ALSO LOWERED TEMPERATURES JUST A BIT DUE TO MORE EXPECTED CLOUD COVER. BMICKELSON PREVIOUS SHORT TERM DISCUSSION...WINDS HAVE FINALLY DIMINISHED TO 10 KNOTS OR LESS ACROSS NORTHEAST MONTANA AT 10Z. THE LIGHT WINDS WILL BE SHORT LIVED AS THE NEXT COLD FRONT MOVES THROUGH TONIGHT WITH A CHANCE OF RAIN OR SNOW. THE FRONT WILL BE FOLLOWED BY STRONG WEST TO NORTHWEST WINDS ON SATURDAY. HAVE ISSUED A HIGH WIND WATCH FOR THE ENTIRE FORECAST AREA FOR SATURDAY AND SATURDAY EVENING. SHORTWAVE RIDGE WILL BRING MILD WEATHER TO THE AREA TODAY BUT IT WILL NOT BE AS WARM AS IT WAS YESTERDAY. CLOUDS WILL INCREASE AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH EASTERN MONTANA TONIGHT. DEEPER MOISTURE MOVES INTO THE AREA THIS EVENING ON SOUTHWEST FLOW ALOFT. THIS WILL BRING A CHANCE OF RAIN STARTING THIS EVENING WITH THE BEST CHANCE OF RAIN SOUTH OF THE MISSOURI RIVER. AS TEMPERATURES COOL ALOFT TONIGHT...RAIN MAY MIX WITH SNOW BEFORE IT MOVES TO THE EAST SATURDAY MORNING. UPPER TROUGH MOVES THROUGH THE AREA ON SATURDAY WITH DECENT COLD AIR ADVECTION. 850 MB WINDS INCREASE TO AROUND 50 KNOTS (GFS SOMEWHAT STRONGER, ECMWF SOMEWHAT WEAKER) SATURDAY MORNING AND REMAIN THERE INTO SATURDAY EVENING. WITH GOOD MIXING AND MOMENTUM TRANSFER EXPECTED ALONG WITH OVER 20 MB PRESSURE RISE...WINDS HAVE A GOOD CHANCE OF REACHING WARNING CRITERIA OF 40 MPH SUSTAINED WITH GUSTS TO 58 MPH. THE STRONGEST WINDS WILL BE IN THE EAST BUT NOT READY TO RULE OUT THE WEST REACHING HIGH WIND CRITERIA. WILL INCLUDE THE ENTIRE FORECAST AREA IN THE HIGH WIND WATCH FOR SATURDAY AND SATURDAY EVENING. COLD AIR ADVECTION WILL LIMIT TEMPERATURE RISES ON SATURDAY AND THE NORTHERN ZONES MAY SEE A FEW FLAKES OF WRAP AROUND SNOW FROM AN UPPER LOW MOVING THROUGH SASKATCHEWAN. HIGH PRESSURE WILL MOVE INTO THE AREA SATURDAY NIGHT. SKIES WILL GRADUALLY CLEAR AND WINDS WILL SLOWLY DIMINISH. TEMPERATURES WILL BE COLDER THAN THEY HAVE BEEN FOR SEVERAL DAYS. THE COLD AIR WILL LINGER INTO SUNDAY WHILE THE NEXT RIDGE BUILDS IN FROM THE WEST. FORRESTER .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY... THE EXTENDED PERIOD BEGINS WITH AN UPPER LEVEL RIDGE AXIS OVER THE ROCKY MOUNTAINS AND NORTHWESTERLY FLOW ALOFT OVER EASTERN MONTANA. THE APPROACHING RIDGE SENDS A WARM FRONT INTO THE FORECAST AREA SUNDAY NIGHT AND MONDAY. THIS WILL ONCE AGAIN RAMP TEMPERATURES ABOVE NORMAL ON MONDAY. MONDAY NIGHT...THE GFS...AND TO A LESSER EXTENT THE EC...PICK UP A DRY SHORTWAVE TROUGH THAT WILL KNOCK DOWN THE RIDGE AND RAMP UP WINDS A BIT THROUGH TUESDAY MORNING. TUESDAY...THE RIDGE RE-ESTABLISHES ITSELF WITH TEMPERATURES TRENDING WELL ABOVE NORMAL...WITH POSSIBLY RECORD HIGHS. THIS RIDGE WILL MAINTAIN RELATIVELY WARM AND DRY CONDITIONS THROUGH THURSDAY. THURSDAY NIGHT AND FRIDAY...AN EASTERN PACIFIC UPPER TROUGH AND STORM SYSTEM SLAMS INTO THE WEST COAST WEDNESDAY NIGHT...THEN SWINGS EAST ACROSS THE DIVIDE BY FRIDAY. 850MB TEMPERATURES QUICKLY FALL TO AROUND -10*C. WITH PRECIPITATION A POSSIBILITY THERE SHOULD BE A TRANSITION FROM RAIN TO SNOW WITH THIS WAVE. THIS WILL BECOME A WINTER STORM OVER WESTERN AND CENTRAL MONTANA...SOME OF WHICH MAY AFFECT OUR WESTERN ZONES FOR A SHORT PERIOD. THIS WAVE WILL ALSO TREND TEMPERATURE DOWN TOWARDS NORMAL. SCT && .AVIATION... VFR TODAY. A SHORT PERIOD UPPER RIDGE WILL BE INTERRUPTED BY A SHORTWAVE TROUGH THIS AFTERNOON WHICH COULD INTRODUCE RAIN AND SNOW SHOWERS THIS EVENING...AFFECTING MAINLY KGDV AND KSDY. THIS COULD PRODUCE MVFR CEILINGS. EXPECT NW WINDS TO BECOME SOUTHERLY THIS AFTERNOON...THEN SOUTHWESTERLY THIS EVENING...ALL AROUND 5-10KTS. SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS...SHERIDAN...WESTERN ROOSEVELT...PETROLEUM... GARFIELD...MCCONE...RICHLAND...DAWSON...PRAIRIE...WIBAUX... NORTHERN PHILLIPS...SOUTHWEST PHILLIPS...NORTHERN VALLEY... EASTERN ROOSEVELT. && $$ WEATHER.GOV/GLASGOW