Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/20/16


AREA FORECAST DISCUSSION
NWS PHOENIX AZ
745 PM MST TUE JAN 19 2016 .SYNOPSIS... A WEAK LOW PRESSURE SYSTEM WILL BRING A CHANCE OF LIGHT PRECIPITATION TO MAINLY NORTHERN ARIZONA TONIGHT. HIGH PRESSURE WILL BUILD ACROSS THE DESERT SOUTHWEST WEDNESDAY CONTINUING INTO THE WEEKEND. TEMPERATURES A FEW DEGREES ABOVE NORMAL ARE EXPECTED BY LATE IN THE WEEK. && .DISCUSSION... A VIGOROUS SHORTWAVE TROUGH WAS PROPAGATING THROUGH NEVADA AND SOUTHEAST CALIFORNIA EARLY THIS EVENING ON THE LEADING EDGE OF A 120KT JET STREAK. STRONG JET LEVEL DIVERGENCE COMBINED WITH MOIST (ALBEIT WEAK) H7 FRONTOGENTICAL FORCING HAS ALLOWED A BAND OF PRECIPITATION TO BE MAINTAINED INTO THE LOWER COLORADO RIVER VALLEY. THE PAST SEVERAL HRRR ITERATIONS HAVE VERY ACCURATELY DEPICTED THIS EVOLUTION...AND EVEN CAPTURE THE CURRENT DETERIORATION STAGE SEEN IN RADAR LOOPS. EARLIER IN THE EVENING...HAD INCREASED POPS THROUGH RIVERSIDE COUNTY TO ACCOUNT FOR RADAR TRENDS YIELDING A MODEST CHANCE...THOUGH LOW QPF EVENT. KEPT ANY PRECIPITATION MENTION EXCLUSIVELY RELEGATED TO LA PAZ AND UPSLOPE AREAS OF MARICOPA AND GILA COUNTIES FOR THE REMAINDER OF THE NIGHT (AND SIMILARLY BARELY MEASURING IN THE BUCKET)...AND PALTRY RADAR TRENDS BEAR THIS TREND OUT. OTHERWISE...BOTH TEMPERATURES AND DEWPOINTS WERE TRENDING SLIGHTLY HIGHER THAN FORECAST GIVEN THE INFUSION OF CLOUDS AND MOISTURE...THOUGH OBSERVATIONAL READINGS SHOULD MODERATE LATER TONIGHT WITH THE PASSAGE OF THE TROUGH AXIS AND CLOUD SHIELD. && .PREVIOUS DISCUSSION... /301 PM MST TUE JAN 19 2016/ RIDGING WILL BUILD INTO THE DESERT SOUTHWEST BEHIND THIS TROUGH ON WEDNESDAY AND REMAIN IN PLACE THROUGH AT LEAST SATURDAY. SATURDAY NIGHT WILL SEE THE TAIL END OF A WEAK TROUGH MOVE THROUGH SOUTHERN CALIFORNIA AND ARIZONA. HOWEVER...A NEGLIGIBLE INCREASE IN PRE- FRONTAL MOISTURE AND LITTLE TO NO NOTEWORTHY ISENTROPIC ASCENT WILL PRECLUDE WIDESPREAD PRECIP DEVELOPMENT ACROSS THE AREA. NAEFS STILL MAINTAINS 10 POPS EAST OF PHOENIX AND THIS SEEMS REASONABLE...OTHERWISE SINGLE DIGIT POPS APPEAR TO BE ALL THAT IS WARRANTED. WEAK RIDGING WILL RETURN EARLY NEXT WEEK. AS FOR TEMPERATURES...EXPECT BOTH HIGHS AND LOWS TO BE WITHIN A FEW DEGREES OF NORMAL THROUGH SATURDAY. WEAK POST-FRONTAL COLD ADVECTION COULD KNOCK TEMPS BACK INTO THE LOW/MID 60S SUNDAY AND MONDAY BUT ASIDE FROM THAT...NO MAJOR DEPARTURES FROM NORMAL ARE EXPECTED AT ANY TIME OVER THE NEXT WEEK. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...AND SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... VERY LITTLE AVIATION CONCERNS THROUGH WEDNESDAY EVENING...WITH THICKER MID/HIGH CIGS AOA 10K FT CLEARING BY SUNRISE WEDNESDAY. VIRGA AND A FEW SPRINKLES REACHING THE SFC MAY BE POSSIBLE THIS EVENING...BUT LITTLE TO IMPACT OPERATIONS. OTHERWISE...SFC WINDS WILL REMAIN LIGHT AND FOLLOW TYPICAL DIURNAL DIRECTION TRENDS AROUND THE PHOENIX AREA...WITH WEST AND NORTH COMPONENTS ACROSS SOUTHEAST CALIFORNIA. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... THURSDAY THROUGH MONDAY... A HIGH PRESSURE RIDGE WILL DOMINATE THE AREA THURSDAY AND FRIDAY BRINGING A SLIGHT WARMING TREND WITH SLIGHTLY ABOVE NORMAL HIGH TEMPERATURES THROUGH FRIDAY. THEN THE NEXT WEAK SYSTEMS MOVE THROUGH FRIDAY NIGHT/SATURDAY MORNING AND SUNDAY HELPING TO BRING HIGH TEMPERATURES BACK TO NEAR NORMAL ON SATURDAY AND SLIGHTLY BELOW NORMAL SUNDAY ALONG WITH VERY LITTLE CHANCE OF RAIN. EXPECT WINDS TO BE GENERALLY LIGHT AND FOLLOW USUAL DIURNAL TENDENCIES WITH SOME AFTERNOON WESTERLY AND NORTHWESTERLY BREEZES ON SUNDAY AFTERNOON IN SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA WITH WIND GUSTS OF ABOUT 15 TO 22 KNOTS. MINIMUM HUMIDITIES WILL RANGE FROM THE MID/UPPER TEENS TO THE LOW/MID 20S PERCENT RANGE ON ALL DAYS EXCEPT FOR SUNDAY WHEN THEY WILL TEMPORARILY BUMP UP TO THE UPPER 20S TO MID 30S PERCENT RANGE. EXPECT GOOD TO EXCELLENT OVERNIGHT RECOVERIES. && .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING PROCEDURES. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...MO/HIRSCH/LEINS AVIATION...MO FIRE WEATHER...SAWTELLE
AS MENTIONED IN PREVIOUS FORECAST DISCUSSIONS...A SLOW MOVING
TRANSIENT RIDGE WILL PASS OVER THE AREA THURSDAY AND FRIDAY
SHIELDING THE AREA FROM SNOW. MODEL AGREEMENT BETWEEN THE ECMWF AND GFS SOLUTIONS NOT GREAT THIS WEEKEND BUT NOT ENTIRELY DISSIMILAR EITHER. IN ANY CASE...BOTH INDICATED THAT UNSETTLED PROGRESSIVE FLOW WILL REDEVELOP WITH SNOW POSSIBLE BOTH SATURDAY AND SUNDAY. LITTLE DISCERNIBLE DETAIL TO BE GLEANED FROM THE LATEST FORECAST RUNS AS TIMING AND DEPTH OF TROUGHS DIFFER. TEMPERATURES THROUGHOUT THE REMAINDER OF THE WEEK WILL BOUNCE UP AND DOWN A BIT WITH THE PASSAGE OF THE SERIES OF SHALLOW TROUGH SYSTEMS DESCRIBED PREVIOUSLY. HOWEVER...THOUGH READINGS WILL SHOW SOME VARIANCE...THEY WILL GENERALLY REMAIN WITHIN A FEW DEGREES OR MORE OF NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1110 AM MST MON JAN 18 2016 WIDESPREAD VFR UNTIL 00Z-03Z WHEN CONDITIONS DETERIORATE FROM RAPIDLY LOWER CIGS AS MOIST TROUGH MOVING INTO WRN COLORADO. CIGS WILL QUICKLY LOWER BELOW ILS BREAKPOINTS AT THE MOUNTAIN TAF SITES WITH AREAS OF IFR CONDITIONS. WIDESPREAD BLO 3SM -SN BR IS EXPECTED BETWEEN 06Z-12Z TONIGHT...ALTHOUGH THE SNOW STAY EAST OF KCNY. RAPID IMPROVEMENT DURING 12Z-18Z TUESDAY WITH IMPROVING VIS AND RISING CIGS ARE EXPECTED...ALTHOUGH CIGS MAY LINGER AT KEGE AND KASE. WIDESPREAD VFR IS EXPECTED BY 15Z-18Z TUESDAY MORNING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR COZ014. UT...NONE. && $$ UPDATE...PF SHORT TERM...EH LONG TERM...NL AVIATION...PF
AREA FORECAST DISCUSSION
NWS ALBANY NY
1230 AM EST MON JAN 18 2016 .SYNOPSIS... A QUICK MOVING...CLIPPER...LOW PRESSURE SYSTEM WILL APPROACH AND WILL MOVE ACROSS THE REGION TONIGHT BRINGING MAINLY A LIGHT SNOWFALL TO THE AREA. IN THE WAKE OF THIS SYSTEM...AN ARCTIC AIRMASS WILL BE USHERED IN ON BRISK AND GUSTY WESTERLY WINDS. TEMPERATURES MONDAY NIGHT WILL DROP INTO THE SINGLE DIGITS AND BELOW ZERO ACROSS MUCH OF THE LOCAL AREA. LAKE EFFECT SNOWS WILL DEVELOP DOWNWIND OF LAKE ONTARIO MONDAY MORNING AND WILL PERSIST THROUGH TUESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1230 AM EST...A FAST MOVING CLIPPER SYSTEM IS HEADED TOWARDS THE AREA. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS NOW LOCATED OVER THE WESTERN MOHAWK VALLEY AND ADIRONDACKS AND HEADING EAST/SOUTHEAST. SOME AREAS OF VERY LIGHT SNOW/SNOW SHOWERS HAS ALREADY BROKEN OUT ACROSS THE MOHAWK VALLEY AND WESTERN ADIRONDACKS...CAPITAL REGION AND OVER WESTERN NEW ENGLAND. HOWEVER...THERE APPEARS TO BE SOME MID LEVEL DRYING AND SUBSIDENCE...POSSIBLY PARTIALLY DUE TO THE DEEPENING LOW PRESSURE SYSTEM OFF THE COAST...WHICH HAS BEEN ALLOWING THE SNOW TO REMAIN VERY LIGHT/LIMITED IN VALLEY AREAS THUS FAR. THE HEAVIER SNOW SHOWERS ALONG THE FRONT ARE NOW LOCATED ACROSS THE WESTERN MOHAWK VALLEY AND ADIRONDACKS...AND HAVE BECOME SOMEWHAT SPOTTY UPON HEADING EAST. STILL EXPECT UP TO A QUICK INCH FROM THIS BAND AS IT CROSSES THE MOHAWK VALLEY AND WESTERN ADIRONDACKS WITHIN A QUICK...45-90 MINUTE PERIOD. THEREAFTER...THE SNOW SHOWERS SHOULD TRANSITION MORE INTO LAKE EFFECT...WITH GREATEST SNOWFALL THROUGH SUNRISE EXPECTED ACROSS CENTRAL AND SOUTHERN HERKIMER CO. FURTHER SOUTH...THE LATEST 3KM HRRR SUGGEST THAT AREAS OF LIGHT SNOW WITH SOME HEAVIER EMBEDDED BURSTS WILL CONTINUE TO MOVE ACROSS THE AREA DURING THE OVERNIGHT HOURS /MAINLY AFTER MIDNIGHT/ AS THE CLIPPER SYSTEM MOVES THROUGH. THERE COULD BE A LOCALIZED SQUALL RIGHT ALONG WITH THE PASSAGE OF THE CLIPPER/S COLD FRONT OVERNIGHT...WITH A BRIEF BURST OF HEAVY SNOW...GUSTY WINDS AND LOW VISIBILITY. ANY SQUALL WILL BE VERY SHORT IN DURATION...AND SHOULD BE LIMITED IMPACT DUE TO IT/S OCCURRING IN THE MIDDLE OF THE NIGHT. STILL...ANY OVERNIGHT TRAVELERS SHOULD BE AWARE THAT THE WEATHER WILL BE LESS THAN IDEAL FOR DRIVING LATE TONIGHT. TOTAL ACCUMS SHOULD MAINLY BE LESS THAN AN INCH IN VALLEY AREAS...EXCEPT POSSIBLY 1-2 INCHES FROM SARATOGA NORTH TO GLENS FALLS. HIGHER TERRAIN SHOULD STILL EXPERIENCE 1-2 INCHES. A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR NORTHERN HERKIMER AND HAMILTON COUNTIES...WHERE THE BEST QPF IS EXPECTED TO OCCUR...AND SOME LAKE ENHANCEMENT/UPSLOPE WILL AID IN ALLOWING SNOWFALL TOTALS OVERNIGHT TO BE AROUND 2-6 INCHES. ELSEWHERE...GENERALLY UP TO AN INCH OR TWO IS EXPECTED...WITH LOCALLY UP TO 3 INCHES IN THE HIGH TERRAIN OF WESTERN NEW ENGLAND WHERE UPSLOPE WILL ALSO AID IN SQUEEZING OUT A LITTLE ADDITIONAL SNOWFALL AS WELL. LIGHT WINDS WILL SHIFT TO THE WEST AND INCREASE WITH THE PASSAGE OF THE ARCTIC BOUNDARY AND MUCH COLDER AIR WILL BEGIN TO BE USHERED ON THE REGION FOR LATE TONIGHT. THESE WINDS WILL CAUSE SOME BLOWING OF THE SNOW. TEMPS WILL ONLY SLOWLY FALL OR NEARLY HOLD STEADY UNTIL THE FRONT PASSES...AND THEN SHOULD REALLY BEGIN TO FALL FAST BEHIND THE ARCTIC BOUNDARY CLOSER TO DAYBREAK. MINS AROUND SUNRISE TOMORROW WILL BE IN THE TEENS TO LOWER 20S. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... TRANSITION TO LAKE EFFECT SNOWS OCCURS IN WAKE OF CLIPPER SYSTEM AS ARCTIC AIRMASS POURS INTO REGION A BRISK AND GUSTY WESTERLY WINDS. HAVE HAD A CHANGE IN HEADLINES...BASED ON EXPECTED TRAJECTORY OF THE LAKE EFFECT SNOWS WARNING CRITERIA SNOW IS NOT EXPECTED IN NORTHERN HERKIMER COUNTY SO HAVE DOWNGRADED THE LAKE EFFECT SNOW WARNING TO A LAKE EFFECT SNOW ADVISORY. KEPT THE TIMING THE SAME...MONDAY THROUGH TUESDAY. THE LAKE EFFECT SNOW WARNING REMAINS IN EFFECT FOR SOUTHERN HERKIMER COUNTY FOR MONDAY THROUGH TUESDAY. THE NEW YORK STATE THRUWAY WILL BE IMPACTED BY THE LAKE EFFECT SNOWS. INITIALLY THE FLOW IN THE WAKE OF THE ARCTIC BOUNDARY WILL BE WESTERLY...HOWEVER IT WILL SHIFT BECOMING MORE NORTHWESTERLY DURING THE DAY. THIS WILL RESULT IN THE LAKE EFFECT SNOWS BEING FOCUSED ACROSS CENTRAL NEW YORK INTO THE WESTERN AND CENTRAL MOHAWK VALLEY AND INTO THE SCHOHARIE VALLEY. HAVE CONFIDENCE FOR WARNING CRITERIA SNOWFALL IN SOUTHERN HERKIMER COUNTY. AT THIS TIME FORECASTING 6 TO 12 INCHES WITH THE BULK OF THE SNOW FALLING MAINLY MONDAY AFTERNOON AND EVENING...HOWEVER THE BRISK AND GUSTY WINDS WILL CAUSING BLOWING AND DRIFTING OF THE SNOW. ADVISORY LEVEL SNOWS ARE POSSIBLE ACROSS THE WESTERN PORTIONS OF SCHOHARIE...MONTGOMERY AND FULTON COUNTIES. HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO ISSUE A LAKE EFFECT SNOW ADVISORY...BUT ONE WILL BE ISSUE IF OUR CONFIDENCE INCREASE. HAVE MENTION IN THE HAZARDOUS WEATHER OUTLOOK. THE MUCH COLDER TEMPERATURES ALONG WITH THE BRISK AND GUSTY WINDS WILL RESULT IN LOW WIND CHILL READINGS...PARTICULARLY MONDAY NIGHT INTO TUESDAY MORNING JUST IN TIME FOR THE KIDS TO GO BACK TO SCHOOL. BASED ON THE CURRENT TEMPERATURE AND WIND FORECAST EXPECTING WIND CHILL READINGS OF 10 DEGREES BELOW ZERO AND COLDER ARE EXPECTED ACROSS THE HIGHER TERRAIN AND THE MOHAWK VALLEY WITH A WIND CHILL ADVISORY POSSIBLY BEING NEEDED ACROSS NORTHERN HERKIMER AND HAMILTON COUNTIES. IN THE VALLEY...WIND CHILL VALUES OF BELOW ZERO ARE EXPECTED. TEMPERATURES AROUND 10 DEGREES BELOW NORMAL ARE EXPECTED MONDAY THROUGH TUESDAY. WINDS WILL REMAIN BRISK AND GUSTY THROUGH TUESDAY NIGHT. THEY WILL BE THE STRONGEST DURING THE DAYTIME MONDAY AND TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... SOME LAKE EFFECT SNOW WILL STILL BE ONGOING ACROSS CENTRAL NEW YORK AT THE START OF THE LONG TERM PERIOD ON WEDNESDAY MORNING. SOME OF THESE SNOW SHOWERS AND FLURRIES MAY SNEAK THEIR WAY INTO THE WESTERN MOHAWK VALLEY...OTHERWISE IT LOOKS TO BE MOSTLY TO PARTLY SUNNY AND COLD ONCE AGAIN ON WEDNESDAY WITH TEMPS REACHING THE MID 20S TO LOW 30S FOR VALLEY AREAS. ANY LAKE EFFECT LOOKS TO DIMINISH IN THE AFTERNOON HOURS....AS AN APPROACHING WEAK UPPER LEVEL SHORTWAVE WILL HELP DISRUPT THE FLOW. THIS WEAK SHORTWAVE MAY ALLOW FOR A FEW LIGHT SNOW SHOWERS ACROSS WESTERN AREAS ON WED NIGHT...OTHERWISE IT LOOKS TO DRY AND COLD WITH A PARTLY TO MOSTLY CLOUDY SKY. OVERNIGHT LOWS ON WED NIGHT WILL BE IN THE SINGLE DIGITS AND TEENS. BEHIND THIS SYSTEM...AN AREA OF HIGH PRESSURE WILL BUILD INTO THE REGION FOR THURSDAY. THIS HIGH PRESSURE WILL KEEP DRY CONDITIONS IN PLACE INTO MUCH OF FRIDAY. TEMPERATURES WILL CONTINUE TO BE BELOW NORMAL WITH HIGHS IN THE 20S...AND OVERNIGHT LOWS IN THE SINGLE DIGITS AND TEENS. THERE IS A GREAT AMOUNT OF UNCERTAINTY REGARDING THE FORECAST FOR FRIDAY NIGHT INTO THE WEEKEND. A STORM SYSTEM THAT WILL BE MOVING FROM THE MISSISSIPPI VALLEY TOWARDS THE OHIO VALLEY ON FRIDAY LOOKS TO REDEVELOP OFF THE MID ATLANTIC COAST FOR FRI NIGHT INTO WEEKEND. AS THIS SYSTEM THEN LIFTS NORTHEAST...THE TRACK OF THIS SYSTEM WILL DETERMINE HOW MUCH PRECIP REACHES INTO OUR AREA. WITH COLD AIR IN PLACE...ANY PRECIP WOULD BE IN THE FORM OF SNOW. AT THIS POINT...AREAS SOUTH AND EAST OF THE CAPITAL REGION HAVE THE HIGHEST CHANCE OF SEEING SOME ACCUMULATING SNOWFALL...AS THE STORMS TRACKS OFF THE EASTERN SEABOARD. MODEL SCENARIOS ARE STILL ALL OVER THE PLACE WITH QPF AMOUNTS...AND THERE IS A LARGE SPREAD IN THE GEFS MEMBERS AS WELL. THE LATEST 12Z GFS WOULD SUGGEST LITTLE TO SNOW FALLS IN THE ALBANY AREA...ALTHOUGH THE 12Z ECMWF/GGEM WOULD HAVE MORE OF AN IMPACT FOR MUCH OF THE CWA. IN ADDITION...THERE IS ALSO UNCERTAINTY WITH THE EXACT TIMING/DURATION OF ANY POTENTIAL EVENT AS WELL. WITH THIS EVENT STILL BEING ALMOST A WEEK AWAY...THIS UNCERTAINTY IS EXPECTED...AND HOPEFULLY MODEL/ENSEMBLE GUIDANCE WILL HELP NARROW THE WINDOW OF SOLUTIONS DURING THE UPCOMING WEEK. FOR NOW...WILL GO WITH CHC POPS FOR SNOW FOR SOUTHERN AREAS...AND SLIGHT CHC FOR FURTHER NORTH. TEMPS WILL CONTINUE TO BE MAINLY IN THE 20S FOR HIGHS...AND TEENS AT NIGHT. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... FLYING CONDITIONS ARE CURRENTLY VFR WITH LIGHT WINDS AND BKN-OVC CIGS AROUND 5-9 KFT. HOWEVER...AN APPROACHING CLIPPER SYSTEM WILL ALLOW FOR SOME LIGHT SNOW SHOWERS/FLURRIES TO BEGIN WITHIN THE NEXT FEW HOURS. FLYING CONDITIONS WILL DROP TO MVFR IN THE NEXT COUPLE OF HOURS AND A PERIOD OF IFR DUE TO VSBYS /AND POSSIBLY CIGS TOO/ LOOKS TO OCCUR FOR THE LATE NIGHT HOURS WITH A PERIOD OF LIGHT SNOWFALL. THE EXCEPTION WILL BE AT KPOU WHERE CIGS AND VSBYS WILL REMAIN VFR. IN ADDITION...WINDS WILL BECOME WESTERLY AND INCREASE TO AROUND 10 KTS WITH SOME HIGHER GUSTS BY LATE TONIGHT BEHIND THE ARCTIC COLD FRONT AS WELL. STEADY SNOW SHOULD TAPER OFF BY AROUND DAYBREAK MONDAY...ALLOWING FLYING CONDITIONS TO RETURN TO MVFR AND EVENTUALLY VFR CONDITIONS. MAINLY VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY MONDAY. CIGS LOOK TO BE BKN-OVC AT 4-6 KFT DUE TO LEFTOVER CLOUDS FROM LAKE EFFECT SNOW TO THE WEST...BUT ANY OF THE SNOW SHOWER ACTIVITY LOOKS TO REMAIN MAINLY WEST OF THE REGION. IT WILL CONTINUE TO BE WINDY...WITH W-NW WINDS AT 10-15 KTS...AND SOME GUSTS UP TO 25 KTS AT TIMES...ESP FOR KALB/KPSF. OUTLOOK... MON NIGHT: LOW OPERATIONAL IMPACT. BRISK. SLIGHT CHANCE OF SHSN. TUE: MODERATE OPERATIONAL IMPACT. WINDY. SLIGHT CHANCE OF SHSN. TUE NIGHT: LOW OPERATIONAL IMPACT. BRISK. WED: NO OPERATIONAL IMPACT. NO SIG WX. WED NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. THU: NO OPERATIONAL IMPACT. NO SIG WX. THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. FRI: NO OPERATIONAL IMPACT. NO SIG WX. && .HYDROLOGY... COLDER AIR RETURNS TO THE HSA AND WILL PERSIST THROUGH THE UPCOMING WEEK. PRECIPITATION TYPE WILL BE SNOW. ICE WILL FORM ON BODIES OF WATER. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...LAKE EFFECT SNOW ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST TUESDAY FOR NYZ032. WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NYZ032-033. LAKE EFFECT SNOW WARNING FROM 6 AM THIS MORNING TO 6 PM EST TUESDAY FOR NYZ038. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA NEAR TERM...IAA/FRUGIS/KL SHORT TERM...IAA LONG TERM...FRUGIS AVIATION...FRUGIS/11 HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1216 AM EST MON JAN 18 2016 .SYNOPSIS... A QUICK MOVING...CLIPPER...LOW PRESSURE SYSTEM WILL APPROACH AND WILL MOVE ACROSS THE REGION TONIGHT BRINGING MAINLY A LIGHT SNOWFALL TO THE AREA. IN THE WAKE OF THIS SYSTEM...AN ARCTIC AIRMASS WILL BE USHERED IN ON BRISK AND GUSTY WESTERLY WINDS. TEMPERATURES MONDAY NIGHT WILL DROP INTO THE SINGLE DIGITS AND BELOW ZERO ACROSS MUCH OF THE LOCAL AREA. LAKE EFFECT SNOWS WILL DEVELOP DOWNWIND OF LAKE ONTARIO MONDAY MORNING AND WILL PERSIST THROUGH TUESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 932 PM EST...A FAST MOVING CLIPPER SYSTEM IS HEADED TOWARDS THE AREA FOR TONIGHT. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS NOW LOCATED OVER CENTRAL NY AND WILL BE APPROACHING OUR WESTERN AREAS VERY SOON. SOME AREAS OF LIGHT SNOW AND SNOW SHOWERS HAS ALREADY BROKEN OUT ACROSS THE MOHAWK VALLEY AND WESTERN ADIRONDACKS...AND SOME ADDITIONAL SNOW SHOWERS HAVE ALSO ALREADY OCCURRED OVER WESTERN NEW ENGLAND AS WELL THANKS TO A DEPARTING COASTAL WAVE. THE MOST HEAVIEST SNOW SHOWERS UPSTREAM ARE OVER THE EASTERN END OF LAKE ONTARIO...AND THESE SNOW SHOWERS...AIDED BY SOME MOISTURE/INSTABILITY THANKS TO LAKE ONTARIO...WILL BE MOVING INTO OUR WESTERN ADIRONDACKS OVER THE NEXT FEW HOURS. THESE SNOW SHOWERS WILL HAVE THE CAPABILITY OF DROPPING A QUICK INCH OR TWO WITHIN A 60-90 MINUTE PERIOD. FURTHER SOUTH...THE 01Z 3KM HRRR SUGGEST THAT AREAS OF LIGHT SNOW WITH SOME HEAVIER EMBEDDED BURSTS WILL CONTINUE TO MOVE ACROSS THE AREA DURING THE OVERNIGHT HOURS /MAINLY AFTER MIDNIGHT/ AS THE CLIPPER SYSTEM MOVES THROUGH. THERE COULD BE A LOCALIZED SQUALL RIGHT ALONG WITH THE PASSAGE OF THE CLIPPER/S COLD FRONT TONIGHT...WITH A BRIEF BURST OF HEAVY SNOW...GUSTY WINDS AND LOW VISIBILITY. ANY SQUALL WILL BE VERY SHORT IN DURATION...AND SHOULD BE LIMITED IMPACT DUE TO IT/S OCCURRING IN THE MIDDLE OF THE NIGHT. STILL...ANY OVERNIGHT TRAVELERS SHOULD BE AWARE THAT THE WEATHER WILL BE LESS THAN IDEAL FOR DRIVING LATE TONIGHT. A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR NORTHERN HERKIMER AND HAMILTON COUNTIES...WHERE THE BEST QPF IS EXPECTED TO OCCUR...AND SOME LAKE ENHANCEMENT/UPSLOPE WILL AID IN ALLOWING SNOWFALL TOTALS OVERNIGHT TO BE AROUND 2-6 INCHES. ELSEWHERE...GENERALLY UP TO AN INCH OR TWO IS EXPECTED...WITH LOCALLY UP TO 3 INCHES IN THE HIGH TERRAIN OF WESTERN NEW ENGLAND WHERE UPSLOPE WILL ALSO AID IN SQUEEZING OUT A LITTLE ADDITIONAL SNOWFALLAS WELL. LIGHT WINDS WILL SHIFT TO THE WEST AND INCREASE WITH THE PASSAGE OF THE ARCTIC BOUNDARY AND MUCH COLDER AIR WILL BEGIN TO BE USHERED ON THE REGION FOR LATE TONIGHT. THESE WINDS WILL CAUSE SOME BLOWING OF THE SNOW. TEMPS WILL ONLY SLOWLY FALL OR NEARLY HOLD STEADY THROUGH THE LATE EVENING...BUT SHOULD REALLY BEGIN TO FALL FAST BEHIND THE ARCTIC BOUNDARY FOR LATE TONIGHT. MINS AROUND SUNRISE TOMORROW WILL BE IN THE TEENS. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... TRANSITION TO LAKE EFFECT SNOWS OCCURS IN WAKE OF CLIPPER SYSTEM AS ARCTIC AIRMASS POURS INTO REGION A BRISK AND GUSTY WESTERLY WINDS. HAVE HAD A CHANGE IN HEADLINES...BASED ON EXPECTED TRAJECTORY OF THE LAKE EFFECT SNOWS WARNING CRITERIA SNOW IS NOT EXPECTED IN NORTHERN HERKIMER COUNTY SO HAVE DOWNGRADED THE LAKE EFFECT SNOW WARNING TO A LAKE EFFECT SNOW ADVISORY. KEPT THE TIMING THE SAME...MONDAY THROUGH TUESDAY. THE LAKE EFFECT SNOW WARNING REMAINS IN EFFECT FOR SOUTHERN HERKIMER COUNTY FOR MONDAY THROUGH TUESDAY. THE NEW YORK STATE THRUWAY WILL BE IMPACTED BY THE LAKE EFFECT SNOWS. INITIALLY THE FLOW IN THE WAKE OF THE ARCTIC BOUNDARY WILL BE WESTERLY...HOWEVER IT WILL SHIFT BECOMING MORE NORTHWESTERLY DURING THE DAY. THIS WILL RESULT IN THE LAKE EFFECT SNOWS BEING FOCUSED ACROSS CENTRAL NEW YORK INTO THE WESTERN AND CENTRAL MOHAWK VALLEY AND INTO THE SCHOHARIE VALLEY. HAVE CONFIDENCE FOR WARNING CRITERIA SNOWFALL IN SOUTHERN HERKIMER COUNTY. AT THIS TIME FORECASTING 6 TO 12 INCHES WITH THE BULK OF THE SNOW FALLING MAINLY MONDAY AFTERNOON AND EVENING...HOWEVER THE BRISK AND GUSTY WINDS WILL CAUSING BLOWING AND DRIFTING OF THE SNOW. ADVISORY LEVEL SNOWS ARE POSSIBLE ACROSS THE WESTERN PORTIONS OF SCHOHARIE...MONTGOMERY AND FULTON COUNTIES. HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO ISSUE A LAKE EFFECT SNOW ADVISORY...BUT ONE WILL BE ISSUE IF OUR CONFIDENCE INCREASE. HAVE MENTION IN THE HAZARDOUS WEATHER OUTLOOK. THE MUCH COLDER TEMPERATURES ALONG WITH THE BRISK AND GUSTY WINDS WILL RESULT IN LOW WIND CHILL READINGS...PARTICULARLY MONDAY NIGHT INTO TUESDAY MORNING JUST IN TIME FOR THE KIDS TO GO BACK TO SCHOOL. BASED ON THE CURRENT TEMPERATURE AND WIND FORECAST EXPECTING WIND CHILL READINGS OF 10 DEGREES BELOW ZERO AND COLDER ARE EXPECTED ACROSS THE HIGHER TERRAIN AND THE MOHAWK VALLEY WITH A WIND CHILL ADVISORY POSSIBLY BEING NEEDED ACROSS NORTHERN HERKIMER AND HAMILTON COUNTIES. IN THE VALLEY...WIND CHILL VALUES OF BELOW ZERO ARE EXPECTED. TEMPERATURES AROUND 10 DEGREES BELOW NORMAL ARE EXPECTED MONDAY THROUGH TUESDAY. WINDS WILL REMAIN BRISK AND GUSTY THROUGH TUESDAY NIGHT. THEY WILL BE THE STRONGEST DURING THE DAYTIME MONDAY AND TUESDAY. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... SOME LAKE EFFECT SNOW WILL STILL BE ONGOING ACROSS CENTRAL NEW YORK AT THE START OF THE LONG TERM PERIOD ON WEDNESDAY MORNING. SOME OF THESE SNOW SHOWERS AND FLURRIES MAY SNEAK THEIR WAY INTO THE WESTERN MOHAWK VALLEY...OTHERWISE IT LOOKS TO BE MOSTLY TO PARTLY SUNNY AND COLD ONCE AGAIN ON WEDNESDAY WITH TEMPS REACHING THE MID 20S TO LOW 30S FOR VALLEY AREAS. ANY LAKE EFFECT LOOKS TO DIMINISH IN THE AFTERNOON HOURS....AS AN APPROACHING WEAK UPPER LEVEL SHORTWAVE WILL HELP DISRUPT THE FLOW. THIS WEAK SHORTWAVE MAY ALLOW FOR A FEW LIGHT SNOW SHOWERS ACROSS WESTERN AREAS ON WED NIGHT...OTHERWISE IT LOOKS TO DRY AND COLD WITH A PARTLY TO MOSTLY CLOUDY SKY. OVERNIGHT LOWS ON WED NIGHT WILL BE IN THE SINGLE DIGITS AND TEENS. BEHIND THIS SYSTEM...AN AREA OF HIGH PRESSURE WILL BUILD INTO THE REGION FOR THURSDAY. THIS HIGH PRESSURE WILL KEEP DRY CONDITIONS IN PLACE INTO MUCH OF FRIDAY. TEMPERATURES WILL CONTINUE TO BE BELOW NORMAL WITH HIGHS IN THE 20S...AND OVERNIGHT LOWS IN THE SINGLE DIGITS AND TEENS. THERE IS A GREAT AMOUNT OF UNCERTAINTY REGARDING THE FORECAST FOR FRIDAY NIGHT INTO THE WEEKEND. A STORM SYSTEM THAT WILL BE MOVING FROM THE MISSISSIPPI VALLEY TOWARDS THE OHIO VALLEY ON FRIDAY LOOKS TO REDEVELOP OFF THE MID ATLANTIC COAST FOR FRI NIGHT INTO WEEKEND. AS THIS SYSTEM THEN LIFTS NORTHEAST...THE TRACK OF THIS SYSTEM WILL DETERMINE HOW MUCH PRECIP REACHES INTO OUR AREA. WITH COLD AIR IN PLACE...ANY PRECIP WOULD BE IN THE FORM OF SNOW. AT THIS POINT...AREAS SOUTH AND EAST OF THE CAPITAL REGION HAVE THE HIGHEST CHANCE OF SEEING SOME ACCUMULATING SNOWFALL...AS THE STORMS TRACKS OFF THE EASTERN SEABOARD. MODEL SCENARIOS ARE STILL ALL OVER THE PLACE WITH QPF AMOUNTS...AND THERE IS A LARGE SPREAD IN THE GEFS MEMBERS AS WELL. THE LATEST 12Z GFS WOULD SUGGEST LITTLE TO SNOW FALLS IN THE ALBANY AREA...ALTHOUGH THE 12Z ECMWF/GGEM WOULD HAVE MORE OF AN IMPACT FOR MUCH OF THE CWA. IN ADDITION...THERE IS ALSO UNCERTAINTY WITH THE EXACT TIMING/DURATION OF ANY POTENTIAL EVENT AS WELL. WITH THIS EVENT STILL BEING ALMOST A WEEK AWAY...THIS UNCERTAINTY IS EXPECTED...AND HOPEFULLY MODEL/ENSEMBLE GUIDANCE WILL HELP NARROW THE WINDOW OF SOLUTIONS DURING THE UPCOMING WEEK. FOR NOW...WILL GO WITH CHC POPS FOR SNOW FOR SOUTHERN AREAS...AND SLIGHT CHC FOR FURTHER NORTH. TEMPS WILL CONTINUE TO BE MAINLY IN THE 20S FOR HIGHS...AND TEENS AT NIGHT. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... FLYING CONDITIONS ARE CURRENTLY VFR WITH LIGHT WINDS AND BKN-OVC CIGS AROUND 5-9 KFT. HOWEVER...AN APPROACHING CLIPPER SYSTEM WILL ALLOW FOR SOME LIGHT SNOW SHOWERS/FLURRIES TO BEGIN WITHIN THE NEXT FEW HOURS. FLYING CONDITIONS WILL DROP TO MVFR IN THE NEXT COUPLE OF HOURS AND A PERIOD OF IFR DUE TO VSBYS /AND POSSIBLY CIGS TOO/ LOOKS TO OCCUR FOR THE LATE NIGHT HOURS WITH A PERIOD OF LIGHT SNOWFALL. THE EXCEPTION WILL BE AT KPOU WHERE CIGS AND VSBYS WILL REMAIN VFR. IN ADDITION...WINDS WILL BECOME WESTERLY AND INCREASE TO AROUND 10 KTS WITH SOME HIGHER GUSTS BY LATE TONIGHT BEHIND THE ARCTIC COLD FRONT AS WELL. STEADY SNOW SHOULD TAPER OFF BY AROUND DAYBREAK MONDAY...ALLOWING FLYING CONDITIONS TO RETURN TO MVFR AND EVENTUALLY VFR CONDITIONS. MAINLY VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY MONDAY. CIGS LOOK TO BE BKN-OVC AT 4-6 KFT DUE TO LEFTOVER CLOUDS FROM LAKE EFFECT SNOW TO THE WEST...BUT ANY OF THE SNOW SHOWER ACTIVITY LOOKS TO REMAIN MAINLY WEST OF THE REGION. IT WILL CONTINUE TO BE WINDY...WITH W-NW WINDS AT 10-15 KTS...AND SOME GUSTS UP TO 25 KTS AT TIMES...ESP FOR KALB/KPSF. OUTLOOK... MON NIGHT: LOW OPERATIONAL IMPACT. BRISK. SLIGHT CHANCE OF SHSN. TUE: MODERATE OPERATIONAL IMPACT. WINDY. SLIGHT CHANCE OF SHSN. TUE NIGHT: LOW OPERATIONAL IMPACT. BRISK. WED: NO OPERATIONAL IMPACT. NO SIG WX. WED NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. THU: NO OPERATIONAL IMPACT. NO SIG WX. THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. FRI: NO OPERATIONAL IMPACT. NO SIG WX. && .HYDROLOGY... COLDER AIR RETURNS TO THE HSA AND WILL PERSIST THROUGH THE UPCOMING WEEK. PRECIPITATION TYPE WILL BE SNOW. ICE WILL FORM ON BODIES OF WATER. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...LAKE EFFECT SNOW ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST TUESDAY FOR NYZ032. WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NYZ032-033. LAKE EFFECT SNOW WARNING FROM 6 AM THIS MORNING TO 6 PM EST TUESDAY FOR NYZ038. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA NEAR TERM...IAA/FRUGIS SHORT TERM...IAA LONG TERM...FRUGIS AVIATION...FRUGIS/11 HYDROLOGY...IAA
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
249 PM CST MON JAN 18 2016 .SHORT TERM...(Tonight) ISSUED AT 248 PM CST MON JAN 18 2016 A robust diurnal CU-field developed across central Illinois this afternoon, mainly along and south of the I-72 corridor. Meanwhile, a persistent band of low clouds extending from Minnesota into west- central Illinois tried to push eastward, but generally stayed west of a Macomb to Jacksonville line. The diurnal clouds will rapidly dissipate toward sunset: however, the band of clouds further west will likely persist into the evening. Models have not been picking up on these clouds at all, with the HRRR 1-hour forecast suggesting clear skies. Based on satellite loops, think they will inch eastward into the Illinois River Valley over the next couple of hours before gradually dissipating later in the evening. Will need to monitor satellite trends closely to see if they spread further or persist longer. At this time, will only bring them to a Galesburg to just west of Springfield line this evening. Elsewhere, skies will remain mostly clear through the night. Overnight low temperatures will be in the single digits above zero across most of the area, but will likely drop a couple degrees below zero across the far north around Galesburg and Lacon. && .LONG TERM...(Tuesday through Monday) ISSUED AT 248 PM CST MON JAN 18 2016 Arctic high pressure area will shift east of the CWA Tuesday and allow a developing weather system in the southern plains to push east and bring precip back into the area beginning late Tue afternoon and continuing through Tue night, then ending Wed morning. Temps thru the period will be cold enough for all snow, so question will be how much snow and when will heaviest snow occur. The models have trended slightly slower with the onset of the snow and this makes sense given the current dryness of the lower layers and the expected southeast winds tomorrow not bringing any moisture into the area. So, believe snow will begin over most of the area after 6pm tomorrow evening, though some light snow may begin in western IL late tomorrow afternoon. Heaviest snowfall track should be from the Jacksonville area to southeast IL, tomorrow evening through after midnight. The main low will be tracking into AR late tomorrow night, but system should be able to spread enough pcpn north into the area. Models indicate good isentropic lift with this system with around 3g/kg of moisture being lifted. However, factors limiting the amount of snowfall will be lack of low level moisture initially, system will be weakening as it moves east, and system will be moving through quickly. So snowfall thinking is 3-4 inches in western IL will be the highest, decreasing to around 3 inches in the southeast, and 2 to 2.5 inches along I-74. This matches up well with other offices and thinking of the WWD graphics. Snow will continue into Wed morning,but only in the east and southeastern parts of the CWA. 1/2 inch will still be possible in the Lawrenceville area before ending by noon. Advisory will be likely in some part of the CWA, but given most of the snow will be third period and still some uncertainty on strength of system, will let overnight shift make final decision on location of advisory. A period of dry weather is then expected Wed night through Thursday as this system pushes east and then next system moves out of the plains toward the area. All models have finally come to some agreement on the track of this next system and it appears that most of the pcpn with it will be south of the CWA. Current forecasts show that a chance of snow is possible in southeast IL Thur night only. Otherwise, dry weather can be expected from Fri into Sunday. Then Sunday night and Monday, models show a clipper system moving across the northern third of the state. This will bring another shot of pcpn to the northern/northeaster/and eastern parts of the CWA. P- type will likely be snow, but with temps being above freezing during the daytime periods, rain, or a mix of rain and snow is not out of the question. Temps will remain cold through Fri night given the continued Arctic air over the area through tomorrow and then the clouds and pcpn expected tomorrow night through Wed, and then again being north of the Thur night/Fri weather system. Over the weekend the pattern will become somewhat zonal and this should allow temps to warm back up to normal or just above normal for Sun and Mon. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 1150 AM CST MON JAN 18 2016 Diurnal clouds continue to develop across central Illinois late this morning as per the NAM CU-rule forecast. While forecast soundings do not have a particularly good handle on the cloud level, area obs are generally showing around 2500ft. Have occasionally seen a BKN ceiling: however, think these will be fleeting and did not include in the TAFs. Have instead gone with SCT025 at all terminals through the afternoon. Will continue to monitor a more significant band of VFR clouds stretching from Minnesota into west-central Illinois to see if they could possibly shift eastward and impact KSPI. Latest satellite loops are beginning to show the cloud area shrinking, so do not think they will get much further eastward. Once any diurnal clouds dissipate toward sunset, skies will be mostly clear tonight before the next system begins approaching from the west Tuesday morning. NAM forecast soundings suggest VFR clouds of 8000 to 10000ft arriving at KSPI/KDEC after 15/16z...then further northeast to the remaining TAF sites by early afternoon. && .ILX Watches/Warnings/Advisories... NONE. && $$ SHORT TERM...Barnes LONG TERM...Auten AVIATION...Barnes
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1150 AM CST MON JAN 18 2016 .UPDATE... ISSUED AT 1050 AM CST MON JAN 18 2016 Very cold weather continues across central Illinois this morning, with 16z/10am temperatures mainly in the single digits above zero. Thanks to a ridge of high pressure approaching from the west, winds are much lighter than they were yesterday...but are still blowing at around 10mph. This is creating wind-chill values of 5 below to 15 below zero. As temperatures slowly warm and winds remain light, wind-chills will rise above advisory criteria by midday. As a result, will allow the Wind Chill Advisory to expire at 11am. Sunny skies prevail across the area this morning, although diurnal clouds are beginning to develop along/south of I-72 and a persistent patch of low clouds extending from Minnesota southward into west-central Illinois is nudging its way eastward. Models are not handling this cloud area very well at all, with the HRRR showing clear skies. Based on satellite loops, have increased sky cover across the far SW CWA along/southwest of a Rushville to Jacksonville line to feature a period of partly to mostly cloudy conditions from late morning into early afternoon. Current thinking is that these clouds will gradually dissipate as the day progresses, but will need to keep an eye on their progress to see how far eastward they spread. && .SHORT TERM...(Today) ISSUED AT 335 AM CST MON JAN 18 2016 A Wind Chill Advisory will continue across central Illinois and parts of southeast Illinois this morning. However, even where the advisory is not in effect, it will still be very cold. Arctic high pressure will continue to spread across the Midwest today. However, by midday, it will feel just a touch less cold across most of the forecast area. The upper level trof axis, and core of the cold air, will continue to pull away from the area today. This fact, and decreasing surface winds due to the approach of the surface ridge axis, will allow Wind Chill values to moderate a bit from the values seen late yesterday and through the night. Aside from the cold, the only other weather concern today is the potential for more clouds by afternoon. An area of low clouds lies along the surface ridge axis from the upper Midwest into the northern Plains. The model guidance is not too bullish overall on these clouds working into the area. However, their current track on satellite suggests at least the western portion of the forecast area my be somewhat cloudier later today than current forecast. Have bumped up sky cover later today to account for this potential, but the coverage may need to be boosted further if trends persist. .LONG TERM...(Tonight through Sunday) ISSUED AT 335 AM CST MON JAN 18 2016 1033 mb Canadian high pressure over eastern KS and western MO and ridging northward to along the MN and Dakotas border, will drift east into IL by Tue morning. This will bring another frigid night to central and southeast IL with fair skies, though lighter WSW winds tonight will keep wind chills from reaching wind chill advisory criteria of -15F. Coldest wind chills northern CWA tonight around 10 below zero. Lows tonight range from near zero northern CWA to 4-7F sw CWA and southeast IL. Clouds to increase from sw to ne across central IL during the day Tue ahead of a weather system moving into the Great Plains. 00Z models have trended a bit quicker spreading chances of light snow into western/sw CWA Tue afternoon though think drier air will initially be virga. Increase chances of light snow to 30-50% from Canton to Springfield west by mid/late Tue afternoon. Highs Tue range from around 20F northern CWA to near 25F far southern CWA along and south of highway 50. A mid level trof to move east into IL by 12Z Wed while weak surface low pressure moves across northern OK/AR. Increasing isentropic lift ahead of this feature over IL Tue night to spread snow eastward across the area during Tue evening and continue overnight Tue night. The snow to diminish from west to east during Wed morning. Total qpf around a quarter inch while snow ratios are 12-15:1 and supports a 2- 4 inch snow fall with locally 4-5 inches sw CWA. Mixed precipitation should stay south of our CWA. A winter weather advisory will likely be needed across area Tue night into Wed morning for these snowfall accumulations with slippery roads likely for Wed morning commute. Temps modify Wed with highs in upper 20s central IL and lower 30s in southeast IL which is still a bit cooler than normal. 00Z GFS, GEM and ECMWF models show a southern stream storm system moving across the Gulf Coast/Southeast States Thu/Fri and keeping brunt of its qpf southeast of central IL and brushing far southeast IL. This storm system will have more gulf moisture to work with and heavier qpf expected to still pass south/se of IL. Have chance pops of light snow southeast IL Thu night and Fri morning while slight chances central areas and dry over IL river valley. Could see mix precipitation along and south of highway 50. Models have not been as consistent with this storm system for past few model runs so less confidence in forecast late this work week. Highs Thu/Fri in the upper 20s and lower 30s with mildest readings in southeast IL. Upper level ridge shifts east toward IL on Saturday and ohio river valley Sunday and to bring with milder temperatures especially on Sunday with highs 35-40F. Have small chances of light rain/snow from Sunday afternoon through Monday due to warm air advection, though models differ on this solution and amounts of qpf. Stayed close to consensus for pops and temperatures early next week. CPC 8-14 day outlook for last week of Jan 25-31 has great than normal chances of above normal temperatures across the country, with IL having 60-65% chance of above normal temperatures. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 1150 AM CST MON JAN 18 2016 Diurnal clouds continue to develop across central Illinois late this morning as per the NAM CU-rule forecast. While forecast soundings do not have a particularly good handle on the cloud level, area obs are generally showing around 2500ft. Have occasionally seen a BKN ceiling: however, think these will be fleeting and did not include in the TAFs. Have instead gone with SCT025 at all terminals through the afternoon. Will continue to monitor a more significant band of VFR clouds stretching from Minnesota into west-central Illinois to see if they could possibly shift eastward and impact KSPI. Latest satellite loops are beginning to show the cloud area shrinking, so do not think they will get much further eastward. Once any diurnal clouds dissipate toward sunset, skies will be mostly clear tonight before the next system begins approaching from the west Tuesday morning. NAM forecast soundings suggest VFR clouds of 8000 to 10000ft arriving at KSPI/KDEC after 15/16z...then further northeast to the remaining TAF sites by early afternoon. && .ILX Watches/Warnings/Advisories... NONE. && $$ UPDATE...Barnes SHORT TERM...BAK LONG TERM...07 AVIATION...Barnes
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1050 AM CST MON JAN 18 2016 .UPDATE... ISSUED AT 1050 AM CST MON JAN 18 2016 Very cold weather continues across central Illinois this morning, with 16z/10am temperatures mainly in the single digits above zero. Thanks to a ridge of high pressure approaching from the west, winds are much lighter than they were yesterday...but are still blowing at around 10mph. This is creating wind-chill values of 5 below to 15 below zero. As temperatures slowly warm and winds remain light, wind-chills will rise above advisory criteria by midday. As a result, will allow the Wind Chill Advisory to expire at 11am. Sunny skies prevail across the area this morning, although diurnal clouds are beginning to develop along/south of I-72 and a persistent patch of low clouds extending from Minnesota southward into west-central Illinois is nudging its way eastward. Models are not handling this cloud area very well at all, with the HRRR showing clear skies. Based on satellite loops, have increased sky cover across the far SW CWA along/southwest of a Rushville to Jacksonville line to feature a period of partly to mostly cloudy conditions from late morning into early afternoon. Current thinking is that these clouds will gradually dissipate as the day progresses, but will need to keep an eye on their progress to see how far eastward they spread. && .SHORT TERM...(Today) ISSUED AT 335 AM CST MON JAN 18 2016 A Wind Chill Advisory will continue across central Illinois and parts of southeast Illinois this morning. However, even where the advisory is not in effect, it will still be very cold. Arctic high pressure will continue to spread across the Midwest today. However, by midday, it will feel just a touch less cold across most of the forecast area. The upper level trof axis, and core of the cold air, will continue to pull away from the area today. This fact, and decreasing surface winds due to the approach of the surface ridge axis, will allow Wind Chill values to moderate a bit from the values seen late yesterday and through the night. Aside from the cold, the only other weather concern today is the potential for more clouds by afternoon. An area of low clouds lies along the surface ridge axis from the upper Midwest into the northern Plains. The model guidance is not too bullish overall on these clouds working into the area. However, their current track on satellite suggests at least the western portion of the forecast area my be somewhat cloudier later today than current forecast. Have bumped up sky cover later today to account for this potential, but the coverage may need to be boosted further if trends persist. .LONG TERM...(Tonight through Sunday) ISSUED AT 335 AM CST MON JAN 18 2016 1033 mb Canadian high pressure over eastern KS and western MO and ridging northward to along the MN and Dakotas border, will drift east into IL by Tue morning. This will bring another frigid night to central and southeast IL with fair skies, though lighter WSW winds tonight will keep wind chills from reaching wind chill advisory criteria of -15F. Coldest wind chills northern CWA tonight around 10 below zero. Lows tonight range from near zero northern CWA to 4-7F sw CWA and southeast IL. Clouds to increase from sw to ne across central IL during the day Tue ahead of a weather system moving into the Great Plains. 00Z models have trended a bit quicker spreading chances of light snow into western/sw CWA Tue afternoon though think drier air will initially be virga. Increase chances of light snow to 30-50% from Canton to Springfield west by mid/late Tue afternoon. Highs Tue range from around 20F northern CWA to near 25F far southern CWA along and south of highway 50. A mid level trof to move east into IL by 12Z Wed while weak surface low pressure moves across northern OK/AR. Increasing isentropic lift ahead of this feature over IL Tue night to spread snow eastward across the area during Tue evening and continue overnight Tue night. The snow to diminish from west to east during Wed morning. Total qpf around a quarter inch while snow ratios are 12-15:1 and supports a 2- 4 inch snow fall with locally 4-5 inches sw CWA. Mixed precipitation should stay south of our CWA. A winter weather advisory will likely be needed across area Tue night into Wed morning for these snowfall accumulations with slippery roads likely for Wed morning commute. Temps modify Wed with highs in upper 20s central IL and lower 30s in southeast IL which is still a bit cooler than normal. 00Z GFS, GEM and ECMWF models show a southern stream storm system moving across the Gulf Coast/Southeast States Thu/Fri and keeping brunt of its qpf southeast of central IL and brushing far southeast IL. This storm system will have more gulf moisture to work with and heavier qpf expected to still pass south/se of IL. Have chance pops of light snow southeast IL Thu night and Fri morning while slight chances central areas and dry over IL river valley. Could see mix precipitation along and south of highway 50. Models have not been as consistent with this storm system for past few model runs so less confidence in forecast late this work week. Highs Thu/Fri in the upper 20s and lower 30s with mildest readings in southeast IL. Upper level ridge shifts east toward IL on Saturday and ohio river valley Sunday and to bring with milder temperatures especially on Sunday with highs 35-40F. Have small chances of light rain/snow from Sunday afternoon through Monday due to warm air advection, though models differ on this solution and amounts of qpf. Stayed close to consensus for pops and temperatures early next week. CPC 8-14 day outlook for last week of Jan 25-31 has great than normal chances of above normal temperatures across the country, with IL having 60-65% chance of above normal temperatures. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 546 AM CST MON JAN 18 2016 VFR conditions should prevail across the central Illinois terminals through the 12Z TAF valid time. The one fly in the ointment is an area of low clouds streaming southeast from the upper Midwest and Northern Plains. These clouds are not especially well handled by the forecast guidance, but satellite extrapolation suggests at least KPIA and KSPI may be impacted by these clouds. While this deck is predominantly VFR, some stations beneath these clouds are reporting MVFR conditions. Northwest winds will trend light/variable tonight as a ridge of high pressure begins to cross the area. && .ILX Watches/Warnings/Advisories... Wind Chill Advisory until 11 AM CST this morning for ILZ027>031- 036>038-040>057-061>063-066. && $$ UPDATE...Barnes SHORT TERM...BAK LONG TERM...07 AVIATION...BAK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
315 AM EST MON JAN 18 2016 .UPDATE... AVIATION AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 342 PM EST SUN JAN 17 2016 COLD ARCTIC HIGH PRESSURE IN THE WAKE OF A FRONT WILL BRING VERY COLD CONDITIONS TO THE AREA TONIGHT INTO EARLY TUESDAY. THE COLDEST NIGHT WILL BE TONIGHT WITH WIND CHILLS LIKELY TO APPROACH 15 TO 20 BELOW ACROSS CENTRAL AND NORTHERN PORTIONS OF CENTRAL INDIANA. DRY WEATHER CAN BE EXPECTED THROUGH TUESDAY UNDER THE INFLUENCE OF THIS HIGH. A WEAK LOW PRESSURE SYSTEM WILL PUSH THROUGH THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...WHICH WILL BRING ANOTHER ROUND OF LIGHT SNOW ACCUMULATIONS TO THE AREA. ADDITIONAL LIGHT ACCUMULATIONS WILL BE POSSIBLE LATER IN THE WEEK AS WELL. && .NEAR TERM /OVERNIGHT/... ISSUED AT 1139 PM EST SUN JAN 17 2016 A BAND OF LIGHT SNOW SHOWERS IS EVIDENT ON RADAR SOUTH OF INDIANAPOLIS. WHILE SATELLITE PRODUCTS ARE NOT PICKING UP ANY CLOUD COVER...OBSERVATIONS ARE SHOWING THE DEVELOPMENT OF CLOUDS AROUND 1500-3000 FT. RADAR WILL BE OVERSHOOTING ANY FLURRIES AROUND THE OUTER EDGES OF THE FORECAST AREA...AND SEE THIS CURRENTLY OVER LAWRENCEVILLE WHERE FLURRIES ARE BEING REPORTED BUT NO ECHOES APPARENT ON RADAR. THIS DEVELOPMENT IS LIKELY DUE TO STEEP LAPSE RATES ACROSS THE AREA. RAP SHOWS THESE LOW LEVEL LAPSE RATES REMAINING IN THE 8 TO 9C RANGE ACROSS THE AREA THROUGH AROUND 7-8Z. THUS HAVE ADDED PARTLY CLOUDY SKIES AND SCATTERED FLURRIES ACROSS THE ENTIRE AREA FOR THE NEXT FEW HOURS AS DEVELOPMENT OF CLOUDS AND FLURRIES COULD OCCUR ANYWHERE DURING THIS TIME. STARTING AROUND 8Z IN THE RAP LAPSE RATES RETURN TO MORE STABLE LEVELS AND SHOULD SEE AN END TO ANY FLURRIES AND EXPECT ANY CLOUDS TO CLEAR THEN. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... ISSUED AT 342 PM EST SUN JAN 17 2016 DRY WEATHER WILL PERSIST THROUGH TUESDAY AFTERNOON AS ARCTIC HIGH SLIDES ACROSS THE AREA. WEAK LOW PRESSURE SYSTEM WILL SLIDE ACROSS THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...AND LIGHT SNOW ACCUMULATIONS APPEAR A GOOD POSSIBILITY. ALL MODEL INDICATIONS POINT TO A SOLID BUT UNSPECTACULAR SYSTEM. SYNOPTIC SUPPORT IS WEAK BUT SUFFICIENT. MODELS MAY BE OVERDOING MOISTURE SLIGHTLY AS THERE IS NEVER REALLY A GREAT FETCH OF POLEWARD MOISTURE TRANSPORT. MESOSCALE SUPPORT MAY COMPENSATE A BIT HOWEVER...AS THERE IS SOME MIDDLING FRONTOGENESIS AND NONZERO BUT WEAK EPV WHICH MAY HELP...AS WELL AS SNOW RATIOS WHICH MAY BE JUST SLIGHTLY ABOVE CLIMATOLOGY FOR THE AREA. IN ALL...EXPECT A SNOWFALL OF 1 TO 3 INCHES...WITH PERHAPS AN ISOLATED POCKET OR TWO APPROACHING 4. CONSENSUS TEMPS APPEARED GENERALLY IN THE BALLPARK...ALTHOUGH DID BUMP DOWN SLIGHTLY AGAIN OWING TO RECENT THIN SNOW COVER. && .LONG TERM /THURSDAY THROUGH SUNDAY/... ISSUED AT 315 AM EST MON JAN 18 2016 A PROGRESSIVE UPPER FLOW WILL CONTINUE THROUGH THE LONG TERM WITH A SOMEWHAT OF A SPLIT FLOW OVER THE CENTRAL AND EASTERN U.S. EARLY ON. HIGH PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES THURSDAY WHILE A SYSTEM IN SOUTHERN STREAM TRACKS ACROSS SOUTHERN U.S. THURSDAY AND TO THE CAROLINAS ON FRIDAY. THIS SYSTEM WILL BRING SIGNIFICANT PRECIPITATION AND POSSIBLE SNOW ACCUMULATIONS OVER THE OHIO VALLEY THURSDAY NIGHT AND FRIDAY. HOWEVER THERE IS A LOT OF UNCERTAINTY ON HOW FAR NORTH THIS PRECIPITATION WILL REACH ACROSS INDIANA. MODELS INDICATE LITTLE OR NO PRECIPITATION ACROSS THE NORTHWEST HALF...WHILE MUCH HEAVIER AMOUNTS OCCUR IN THE EAST AND SOUTH. WILL CONTINUE WITH A BLEND AND GO SLIGHT CHANCE POPS ACROSS NORTHWEST HALF AND CHANCE POPS IN THE SOUTHEAST THURSDAY NIGHT AND FRIDAY. WILL ALSO CONTINUE LOW CHANCE POPS EAST FRIDAY EVENING...THEN DRY MOST AREAS UNTIL LATE SUNDAY AS WEAK HIGH PRESSURE MOVES EAST ACROSS OUR REGION. THE GFS SPREADS MIXED RAIN AND SNOW INTO OUR AREA LATE SUNDAY...WHILE THE EURO KEEPS US MOSTLY DRY UNTIL AFTER THE LONG TERM PERIOD. OVERALL MODEL INITIALIZATION SEEMS REASONABLE ON TEMPERATURES. MADE A FEW TWEAKS...BUT NO SIGNIFICANT CHANGES. MODELS INDICATE TEMPERATURES WILL MODERATE A LITTLE BY EARLY NEXT WEEK. && .AVIATION /DISCUSSION FOR THE 180900Z KIND TAF UPDATE/... ISSUED AT 315 AM EST MON JAN 18 2016 MINOR TWEAKS MADE TO KIND TAF TO BETTER MATCH CURRENT CONDITIONS. NO OTHER CHANGES ARE NEEDED AT THIS TIME. PREVIOUS AVIATION DISCUSSION FOLLOWS... VERY STEEP LOW LEVEL LAPSE RATES UNDER STRONG COLD ADVECTION CONTINUES TO PRODUCE SOME CLOUD COVER AROUND 025...ALONG WITH SOME FLURRIES. SHORT TERM MODEL GUIDANCE SUGGESTS THE COLD ADVECTION WILL SLACKEN OFF A BIT OVER THE NEXT FEW HOURS...SO LINGERING CLOUD COVER NEAR THIS LEVEL WILL EVENTUALLY DISSIPATE. ANY CEILINGS/VISIBILITY RESTRICTIONS SHOULD BE BRIEF AND LOCALIZED. ADDITIONAL CLOUD COVER BASED AROUND 025 MAY DEVELOP TOWARDS MIDDAY ON MONDAY AS LOW LEVEL LAPSE RATES STEEPEN UP AGAIN. SURFACE WINDS GENERALLY 270-290 DEGREES AT 9-12 KTS THROUGH MIDDAY MONDAY. && .IND WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON EST MONDAY FOR INZ021-028>031- 035>049-051>057-065. && $$ SYNOPSIS...NIELD NEAR TERM...CP SHORT TERM...NIELD LONG TERM...JH AVIATION...JAS/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1147 PM EST SUN JAN 17 2016 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... ISSUED AT 342 PM EST SUN JAN 17 2016 COLD ARCTIC HIGH PRESSURE IN THE WAKE OF A FRONT WILL BRING VERY COLD CONDITIONS TO THE AREA TONIGHT INTO EARLY TUESDAY. THE COLDEST NIGHT WILL BE TONIGHT WITH WIND CHILLS LIKELY TO APPROACH 15 TO 20 BELOW ACROSS CENTRAL AND NORTHERN PORTIONS OF CENTRAL INDIANA. DRY WEATHER CAN BE EXPECTED THROUGH TUESDAY UNDER THE INFLUENCE OF THIS HIGH. A WEAK LOW PRESSURE SYSTEM WILL PUSH THROUGH THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...WHICH WILL BRING ANOTHER ROUND OF LIGHT SNOW ACCUMULATIONS TO THE AREA. ADDITIONAL LIGHT ACCUMULATIONS WILL BE POSSIBLE LATER IN THE WEEK AS WELL. && .NEAR TERM /OVERNIGHT/... ISSUED AT 1139 PM EST SUN JAN 17 2016 A BAND OF LIGHT SNOW SHOWERS IS EVIDENT ON RADAR SOUTH OF INDIANAPOLIS. WHILE SATELLITE PRODUCTS ARE NOT PICKING UP ANY CLOUD COVER...OBSERVATIONS ARE SHOWING THE DEVELOPMENT OF CLOUDS AROUND 1500-3000 FT. RADAR WILL BE OVERSHOOTING ANY FLURRIES AROUND THE OUTER EDGES OF THE FORECAST AREA...AND SEE THIS CURRENTLY OVER LAWRENCEVILLE WHERE FLURRIES ARE BEING REPORTED BUT NO ECHOES APPARENT ON RADAR. THIS DEVELOPMENT IS LIKELY DUE TO STEEP LAPSE RATES ACROSS THE AREA. RAP SHOWS THESE LOW LEVEL LAPSE RATES REMAINING IN THE 8 TO 9C RANGE ACROSS THE AREA THROUGH AROUND 7-8Z. THUS HAVE ADDED PARTLY CLOUDY SKIES AND SCATTERED FLURRIES ACROSS THE ENTIRE AREA FOR THE NEXT FEW HOURS AS DEVELOPMENT OF CLOUDS AND FLURRIES COULD OCCUR ANYWHERE DURING THIS TIME. STARTING AROUND 8Z IN THE RAP LAPSE RATES RETURN TO MORE STABLE LEVELS AND SHOULD SEE AN END TO ANY FLURRIES AND EXPECT ANY CLOUDS TO CLEAR THEN. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... ISSUED AT 342 PM EST SUN JAN 17 2016 DRY WEATHER WILL PERSIST THROUGH TUESDAY AFTERNOON AS ARCTIC HIGH SLIDES ACROSS THE AREA. WEAK LOW PRESSURE SYSTEM WILL SLIDE ACROSS THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...AND LIGHT SNOW ACCUMULATIONS APPEAR A GOOD POSSIBILITY. ALL MODEL INDICATIONS POINT TO A SOLID BUT UNSPECTACULAR SYSTEM. SYNOPTIC SUPPORT IS WEAK BUT SUFFICIENT. MODELS MAY BE OVERDOING MOISTURE SLIGHTLY AS THERE IS NEVER REALLY A GREAT FETCH OF POLEWARD MOISTURE TRANSPORT. MESOSCALE SUPPORT MAY COMPENSATE A BIT HOWEVER...AS THERE IS SOME MIDDLING FRONTOGENESIS AND NONZERO BUT WEAK EPV WHICH MAY HELP...AS WELL AS SNOW RATIOS WHICH MAY BE JUST SLIGHTLY ABOVE CLIMATOLOGY FOR THE AREA. IN ALL...EXPECT A SNOWFALL OF 1 TO 3 INCHES...WITH PERHAPS AN ISOLATED POCKET OR TWO APPROACHING 4. CONSENSUS TEMPS APPEARED GENERALLY IN THE BALLPARK...ALTHOUGH DID BUMP DOWN SLIGHTLY AGAIN OWING TO RECENT THIN SNOW COVER. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY NIGHT/... ISSUED AT 234 PM EST SUN JAN 17 2016 APPEARS THIS PATTERN OF EVERY OTHER DAY SNOW CHANCES WILL CONTINUE THROUGH THE EXTENDED PERIOD AS ANOTHER SYSTEM IS PROJECTED BY THE ENSEMBLES TO MOVE ACROSS THE AREA THURSDAY NIGHT INTO EARLY FRIDAY. THIS SYSTEM MAY CONTAIN A LITTLE MORE IN THE WAY OF MOISTURE AND FORCING LOOKS ESPECIALLY DECENT/GOOD ACROSS THE OHIO RIVER VALLEY AND SURROUNDING REGION. IT IS POSSIBLE AT LEAST 1 TO 2 INCHES OF SNOW COULD FALL DURING THIS TIME ACROSS THE SOUTHEAST COUNTIES...OF COURSE THIS IS VERY EARLY IN THE FORECAST PROCESS TO BE DISCUSSING EXACT SNOWFALL TOTAL AMOUNTS...BUT HAVE NOTED THAT THIS SYSTEM MAY PRODUCE MORE THAN A FEW TENTHS OF AN INCH OF SNOW. IN ADDITION THE FOCUS IS MAINLY FOR BETTER CHANCES (POPS) SOUTH OF THE INTERSTATE 70 CORRIDOR. THEN DRY WEATHER WILL PREVAIL FOR THE NEXT TWO DAYS BEFORE THE NEXT SYSTEM APPROACHES THE AREA EARLY NEXT WEEK. && .AVIATION /DISCUSSION FOR THE 180600Z TAFS/... ISSUED AT 1133 PM EST SUN JAN 17 2016 VERY STEEP LOW LEVEL LAPSE RATES UNDER STRONG COLD ADVECTION CONTINUES TO PRODUCE SOME CLOUD COVER AROUND 025...ALONG WITH SOME FLURRIES. SHORT TERM MODEL GUIDANCE SUGGESTS THE COLD ADVECTION WILL SLACKEN OFF A BIT OVER THE NEXT FEW HOURS...SO LINGERING CLOUD COVER NEAR THIS LEVEL WILL EVENTUALLY DISSIPATE. ANY CEILINGS/VISIBILITY RESTRICTIONS SHOULD BE BRIEF AND LOCALIZED. ADDITIONAL CLOUD COVER BASED AROUND 025 MAY DEVELOP TOWARDS MIDDAY ON MONDAY AS LOW LEVEL LAPSE RATES STEEPEN UP AGAIN. SURFACE WINDS GENERALLY 270-290 DEGREES AT 9-12 KTS THROUGH MIDDAY MONDAY. && .IND WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON EST MONDAY FOR INZ021-028>031- 035>049-051>057-065. && $$ SYNOPSIS...NIELD NEAR TERM...CP SHORT TERM...NIELD LONG TERM...SMF AVIATION...JAS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
535 PM CST TUE JAN 19 2016 ...AVIATION UPDATE... .SYNOPSIS... ISSUED AT 243 PM CST TUE JAN 19 2016 A SHRTWV TROF ADVECTING THROUGH NW FLOW LEAD TO SNOW ACROSS THE IOWA AND N MO THIS AFTERNOON. SNOWFALL TOTALS OF 1 TO 4 INCHES HAVE BEEN REPORTED IN SW IA INTO S CENTRAL IA. THIS FEATURE WILL MOVE TO THE EAST THROUGH THE REST OF TODAY. AS THE COLUMN BEGINS TO SATURATE...SNOW WILL OVERSPREAD THE CWA THIS EVENING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 243 PM CST TUE JAN 19 2016 MAIN FORECAST CONCERN FOR THE SHORT TERM IS THE SNOW THIS AFTERNOON AND INTO THE EVENING. GUIDANCE AND OBSERVATIONAL TRENDS SUGGESTS THAT HEAVIEST SNOW...4+ INCHES...WILL OCCUR JUST TO THE SOUTH OF THE CWA. AS A RESULT...UPDATED SNOW TOTALS AND CURRENT CHANGES TO THE FORECAST WILL RESULT IN THE ADDITION OF MCDONOUGH COUNTY IN THE WS.Y. THE BEST CHANCE FOR 3+ INCHES WILL BE SOUTH OF A LINE FROM MACOMB TO KEOSAUQUA. HIRES GUIDANCE....SPECIFICALLY THE HRRR AND HIRES NMM KEEPS THE HEAVIEST SNOW TO OUR SOUTH THIS EVENING. THIS LINES UP WITH AN OMEGA SIGNAL IN THE DGZ AS WELL. IT APPEARS THAT LIGHT SNOW WILL OVERSPREAD THE AREA FROM WEST TO EAST. NEAR 00Z...AS THE OMEGA INCREASES ACROSS THE SOUTH...SNOW INTENSITY SHOULD PICK UP. AT THIS TIME...THE VORT WILL BE QUICKLY MOVING THROUGH LEADING TO A QUICK END TO THE SNOW FROM WEST TO EAST. THINK THAT MOST OF THE SNOW WILL BE OVER AOA 06Z WED. A LOOK AT THE FORECAST PLUMES SUGGESTS THAT THE HIGHEST CONFIDENCE FOR 3+ INCHES WILL BE ACROSS OUR EXTREME SOUTH. SNOW TOTALS SHOULD RAPIDLY DECREASE AS YOU MOVE NORTH OF HWY 34 CORRIDOR WITH THE QC SEEING AROUND AN INCH TOTAL. THIS IS SUPPORTED BY THE HIRES GUIDANCE AND ENSEMBLE OUTPUT. PAST THIS..IT LOOKS LIKE SOME OF THE WARMEST TEMPS IN THE PAST COUPLE OF DAYS WILL BE TOMORROW WITH NO CHANCE OF POPS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 243 PM CST TUE JAN 19 2016 QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA WEDNESDAY NIGHT THROUGH THURSDAY AS HIGH PRESSURE QUICKLY MOVES THROUGH THE AREA. TEMPERATURES WILL AVERAGE BELOW NORMAL. ON THURSDAY NIGHT...MAINLY DRY CONDITIONS ARE EXPECTED AS THE HIGH MOVES INTO THE OHIO VALLEY. A WEAK DISTURBANCE MOVING THROUGH THE UPPER MIDWEST MAY BRING SOME FLURRIES OR VERY LIGHT SNOW TO THE HIGHWAY 20 CORRIDOR WEST OF DUBUQUE. DRY CONDITIONS WILL THEN BE SEEN ACROSS THE AREA ON FRIDAY AS ANOTHER HIGH PRESSURE BUILDS INTO THE MIDWEST. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL. FRIDAY NIGHT ON... THE MODEL CONSENSUS HAS DRY CONDITIONS FRIDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE MOVES INTO THE OHIO VALLEY. TEMPERATURES WILL SLOWLY CLIMB TO ABOVE NORMAL ON SUNDAY. ATTENTION THEN TURNS TO A POTENTIAL STORM SYSTEM. SUNDAY NIGHT INTO MONDAY THE MODELS DIVERGE ON THEIR RESPECTIVE SOLUTIONS. THE ECMWF IS DRY BUT THE GEM AND TO A MUCH LESSER EXTENT THE GFS SUGGEST A WEAK STORM SYSTEM MOVING THROUGH THE AREA. GIVEN THE CONSIDERABLE DIFFERENCES...THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS FOR SUNDAY NIGHT AND MONDAY. MONDAY NIGHT AND TUESDAY THE MODEL CONSENSUS HAS DRY CONDITIONS AS HIGH PRESSURE BUILDS INTO THE MIDWEST. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 524 PM CST TUE JAN 19 2016 A LIGHT SNOW EVENT WILL OCCUR THIS EVENING...FROM WEST TO EAST OVER EASTERN IOWA AND NORTHERN ILLINOIS. THIS WILL BRING VISIBILITIES DOWN TO IFR...AND CIGS TO MVFR FOR A PERIOD THIS EVENING...LIKELY BETWEEN 00Z AND 04Z...BEFORE LIFTING BACK TO HIGHER END MVFR LATE THIS EVENING. SNOW SHOULD ACCUMULATE TO A SMALL AMOUNT UNDER 2 INCHES AT ALL TAF SITES. WHILE THE CONDITIONS SHOULD IMPROVE AFTER THE SNOW ENDS...THIS WILL BE TEMPORARY...AS THE LIGHT MOIST FLOW IS LIKELY TO SEE LOW CLOUDS AND AND LIGHT FOG DEVELOP AGAIN TOWARD MORNING...WHICH WILL THEN LINGER INTO MID DAY WEDNESDAY. EXPECT IMPROVEMENT TO HIGH END MVFR TO LOWER VFR BY 18Z WEDNESDAY. WINDS WILL BE LIGHT SOUTH TO EAST DURING THE PERIOD. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LEE-VAN BUREN. IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR HANCOCK- MCDONOUGH. MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK- SCOTLAND. && $$ SYNOPSIS...GIBBS SHORT TERM...GIBBS LONG TERM...08 AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
432 PM MST TUE JAN 19 2016 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 210 PM MST TUE JAN 19 2016 EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS RIDGING ACROSS THE ROCKIES WITH A SHORTWAVE TROUGH TRANSITIONING OUT OF THE PLAINS TOWARDS THE CENTRAL MISSISSIPPI RIVER VALLEY. ANOTHER SHORTWAVE TROUGH UPSTREAM OF THE RIDGE IS MOVING INTO THE PACIFIC NORTHWEST WITH A MUCH STRONGER WEST-EAST ORIENTATED UPPER LEVEL JET OVER NORTHERN CALIFORNIA. AT THE SURFACE LEE TROUGH HAS DEVELOPED OVER EAST CENTRAL COLORADO (NEAR FRONT RANGE) AND WARM FRONT IS IN THE PROCESS OF LIFTING OVER THE NORTHEAST PART OF OUR CWA (FROM KMCK TO KHLC). PERSISTENT STRATUS IS STILL IN PLACE IN OUR EASTERN CWA WITH CLOUD SHIELD BREAKING UP IN THE WEST. THIS EVENING-WEDNESDAY MORNING...MAIN CONCERN WILL FOCUS ON POSSIBLE DENSE FOG DEVELOPMENT THIS EVENING/OVERNIGHT. MODELS SUPPORT LEE TROUGH SHIFTING EASTWARD WITH SOUTHERLY FLOW QUICKLY DEVELOPING AFTER SUNSET. THIS SHOULD HELP ADVECT GOOD BL MOISTURE BACK INTO OUR CWA AND STRATUS IN THE EAST COULD THEN EXPAND WESTWARD. EARLIER HRRR/RAP SUPPORTED FOG REDEVELOPING AFTER 00Z THIS EVENING NEAR THE CO/KS BORDER AND SPREADING EASTWARD. LATEST SREF/NAM/RAP/HRRR NOW SHOWING STRONGER SIGNAL AFTER MIDNIGHT TONIGHT THROUGH EARLY WEDNESDAY MORNING WITH MAIN FOG AXIS SHIFTED FURTHER EAST (TOWARD BACK EDGE OF CURRENT STRATUS DECK). I KEPT FOG COVERAGE/TIMING SIMILAR TO EARLY GUIDANCE COVER POSSIBILITY...HOWEVER CONFIDENCE AT THIS POINT IS SIGNIFICANTLY LOWER ON WHERE OR IF DENSE FOG MAY DEVELOP OVER OUR CWA. (FOG MAY BE A GOOD BET BUT DENSE FOG MAY BE PATCHY). WEDNESDAY...TWO SHORTWAVES ARE EXPECTED TO MOVE ACROSS THE ROCKIES AND OVER OUR CWA WITH THE FIRST (WEAKER) SHORTWAVE MOVING OVER OUR CWA MIDDAY WEDNESDAY. AS WAS INDICATED IN EARLIER GUIDANCE ON MID SHIFT THERE IS A SIGNIFICANT DRY LAYER FROM ABOVE THE BL TO 600- 700MB. DESPITE FORCING THIS LOWERS CONFIDENCE IN ANY MEASURABLE PRECIP DURING THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON THE SECOND (STRONGER) SHORTWAVE TROUGH DIGS SOUTHEAST AND OVERTAKES THE FIRST TROUGH WITH A STRONGER UPPER LEVEL JET BEGINNING TO DEVELOP. BY LATE AFTERNOON THERE IS A WEAK PRECIP SIGNAL IN OUR FAR EASTERN CWA AND GUIDANCE THERE DOES SHOW SOME MOISTENING OF THE MOISTURE PROFILE. I KEPT SMALL AREA OF SLIGHT CHANCE POPS IN GRAHAM/NORTON COUNTIES TO MATCH THIS...BUT CONFIDENCE IS STILL NOT HIGH THAT THINGS WOULD START THIS EARLY. OTHER CONCERN FOR WEDNESDAY WILL BE HIGHS. POTENTIAL EXISTS AGAIN FOR LINGERING STRATUS...HOWEVER WITH TROUGHS MOVING THROUGH THE REGION THICK/OPAQUE MID-HIGH CLOUD COVER COULD ALSO LIMIT DIURNAL HEATING. I LOWERED HIGHS IN THE EAST FROM PREVIOUS FORECAST DUE TO POTENTIAL IMPACTS OF CLOUD COVER. TOUGH CALL AND IF WE WERE TO CLEAR OUT (MORE LIKELY IN THE WEST) WE COULD SEE HIGHS IN THE UPPER 40S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 248 PM MST TUE JAN 19 2016 FORECAST ISSUES WILL BE CHANCE OF PRECIPITATION AND PHASE OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY. SATELLITE SHOWING A SOMEWHAT AMPLIFIED BUT STILL PROGRESSIVE AND ACTIVE FLOW PATTERN FROM THE PACIFIC INTO THE WESTERN ATLANTIC. LARGE AND COMPLICATED UPPER TROUGH IS OVER THE NORTHEAST PACIFIC. AT JET LEVEL...THE MODELS WERE HAVING A LITTLE TROUBLE WITH THE JET ALONG THE WEST COAST. AT MID LEVELS...MODELS WERE ALL ABOUT THE SAME BUT THEY WERE ALSO A LITTLE FAR EAST/FAST WITH THE UPPER TROUGH NOW COMING ON THE COAST. THE NAM/ECMWF WAS DOING THE BEST ON THE SURFACE WIND AND PRESSURE FIELD. THE GFS AND CANADIAN WERE DOING THE BEST ON THE LOW LEVEL THERMAL FIELD WITH MOST MODELS NOT BEING COLD ENOUGH. WEDNESDAY NIGHT...DEVELOPING PRECIPITATION EVENT IS IN ITS BEGINNING STAGES. MODELS DIFFERENT ON SPEED...POSITION AND AMPLITUDE OF MID LEVEL CIRCULATION THAT APPEARS TO BE DEVELOPING ON TOP OF US OR JUST TO THE EAST OF US. TODAYS MODEL RUNS VERY DIFFERENT THAN 24 HOURS AGO. BY THE BEGINNING OF THIS PERIOD...MODELS STILL HAVE STRONG NORTH TO SOUTH JET ON THE WEST SIDE OF THIS UPPER SYSTEM. THIS COMBINED WITH THE PROBLEM OF THE MODELS INITIALLY HAVING THIS SYSTEM TOO FAR EAST THIS MORNING...LEADS ME TO BELIEVE THAT WHATEVER ENDS UP BEING THE SLOWER AND EVEN FURTHER SOUTH SOLUTION WILL END UP BEING MORE RIGHT. EVEN NOW AM THINKING CURRENT MODEL RUN STILL MAY BE TOO FAST/FAR NORTH. TROUGH IS ELONGATED AND COMPROMISED OF A NORTHERN AND SOUTHERN CIRCULATIONS WITHIN THIS TROUGH. PAST EXPERIENCE HAS SHOWN THIS SETUP IS NOT GREAT FOR A LOT OF PRECIPITATION. SAYING ALL THAT...THE FAR EASTERN PORTION OF THE AREA WILL HAVE THE BEST CHANCE WITH BEST CHANCE OVERALL AT THIS TIME BEING TO THE EAST OF OUR AREA. THE GRADIENT OF THE CHANCE OF PRECIPITATION WILL BE REALLY SHARP. PER THE REASONING ABOVE...AM THINKING THAT THE BEST CHANCE OF PRECIPITATION WILL BE AFTER MIDNIGHT AND THAT IS SUPPORTED BY THE SREF PROBABILITIES. BEST CHANCE WILL BE VERY LATE IN THE NIGHT. THERE IS NOT A LOT OF COLD AIR WITH THIS SYSTEM...AND DEPENDING ON WHICH MODEL YOU CHOOSE THE CHANGE OVER MAY NOT OCCUR UNTIL LATE EVENING/AROUND MIDNIGHT WITH THE EASTERN AREAS CHANGING OVER FIRST. THE PHASE IS REALLY WHERE THERE ARE BIG DIFFERENCES. SOME MODELS KEEPING TOTALLY DRY OR HAVE JUST ENOUGH MOISTURE IN THE LOW LEVELS FOR DRIZZLE/FREEZING DRIZZLE. SO A LOT OF UNCERTAINTY WITH THIS SYSTEM. THURSDAY/THURSDAY NIGHT...WITH THE PROXIMITY OF THE SYSTEM AND EXPECTED SLOWNESS...ALONG WITH MID AND UPPER LEVEL LIFT EXPECTED...EXPECT THE BEST CHANCE OF PRECIPITATION WILL BE IN THE MORNING AND THEN RAPIDLY DECREASE AND END. IF CURRENT FORECAST PANS OUT...THE FAR EASTERN PORTION OF THE AREA GETS 1 TO 2 INCHES. GRADIENT AND DOWNWARD MOTION BEHIND THE SYSTEM WILL CREATE BREEZY TO WINDY CONDITIONS. THE STRONGEST WINDS ARE AFTER THE SNOW ENDS...AND WITH TEMPERATURES JUST ABOVE FREEZING...DO NOT EXPECT ANY BLOWING SNOW PROBLEMS AT THIS TIME. CURRENT HIGH TEMPERATURE FORECAST LOOKS TO BE IN GOOD SHAPE AND MADE ONLY MINOR ADJUSTMENTS. HOWEVER...IF MORE SNOW THAN EXPECT IT WILL BE COLDER. LIGHT WINDS AND LITTLE CLOUD COVER WILL ALLOW OVERNIGHT TEMPERATURES TO DROP A DECENT AMOUNT. FRIDAY...STRONG MID/UPPER LEVEL RIDGE BUILDS IN OVER THE AREA. SURFACE WILL MOVE THROUGH AND TO THE EAST OF THE AREA DURING THE DAY. SO DO EXPECT RECYCLED COOL AIR. THE EASTERN LOCATIONS WILL BE THE COLDEST AND OVERALL REDUCED THE HIGH TEMPERATURES A LITTLE. FRIDAY NIGHT THROUGH TUESDAY...MID AND UPPER RIDGE WILL BE IN PLACE FROM FRIDAY NIGHT INTO SATURDAY NIGHT SO EXPECT MODERATING TEMPERATURES AND DRY CONDITIONS. THE INIT WAS REASONABLE WITH THIS AND MADE NO CHANGES. A STRONG SHORTWAVE TROUGH...NOT UNLIKE THE ONE THAT WENT THROUGH THIS MORNING AND SIMILAR ALSO THE SYSTEM EXPECTED WEDNESDAY NIGHT AND THURSDAY...WILL MOVE THROUGH SUNDAY AND SUNDAY NIGHT. THE INIT PRODUCED SLIGHT CHANCE POPS DURING THIS PERIOD AND SEEMS REASONABLE. POSSIBLE THAT THESE CHANCES WILL INCREASE. AFTER THAT RIDGING WILL MOVE INTO THE AREA AND BRING DRY CONDITIONS AND MODERATING TEMPERATURES ONCE AGAIN. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 424 PM MST TUE JAN 19 2016 VFR CONDITIONS WILL CONTINUE AT KGLD THIS EVENING AND THEN LOWER TO MVFR OVERNIGHT. CONFIDENCE IN JUST HOW LOW CONDITIONS COULD DROP AT KGLD IS LOW. THE PREVIOUS FORECAST WAS PESSIMISTIC BUT THE LATEST HRRR DOES NOT FAVOR FOG DEVELOPMENT AT KGLD. IF CONDITIONS LOWER OVERNIGHT, THEY SHOULD IMPROVE TO VFR BY MID MORNING AND CONTINUE THROUGH THE AFTERNOON. THE LATEST SATELLITE AT KMCK INDICATES CONDITIONS AT KMCK SHOULD IMPROVE TO VFR SHORTLY. MODELS BRING CONDITIONS BACK DOWN TO MVFR BY 04Z AND THIS SEEMS REASONABLE BASED ON FAVORABLE BOUNDARY LAYER RH. CONDITIONS SHOULD IMPROVE BY LATE MORNING WITH VFR FOR THE REST OF THE TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...FS
AREA FORECAST DISCUSSION
NWS WICHITA KS
1133 PM CST SUN JAN 17 2016 ...UPDATED FOR 06Z AVIATION DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 335 PM CST SUN JAN 17 2016 ELONGATED BAND OF -SHSN PERSISTING ACROSS FORECAST AREA LATE THIS AFTERNOON...DUE TO PERSISTENT...MOIST...ISENTROPIC UPGLIDE 285-290K THETA SURFACES...ENHANCED BY WEAK JET STREAK APPARENT IN WATER VAPOR IMAGERY. 06UTC NAM PROVIDED SOME HINT...AND 17UTC RAP APPEARS TO BE BEST PREDICTIVE VALUE AT PRESENT. EXPECT POTENTIAL FOR SNOW SHOWERS TO DIMINISH BY EARLY TO MID-EVENING. AFTER SNOW CHANCES DIMINISH...MAY FORECAST CONCERN WILL BE OVERNIGHT TEMPERATURES. CLOUD COVER WILL PERSIST MOST OF THE NIGHT...WHICH WILL HELP COUNTER RADIATIVE AND ADVECTION COOLING. DUE TO SNOW PACK ACROSS NORTHEAST KANSAS...TRENDED SLIGHTLY COLDER THAN GUIDANCE FLINT HILLS INTO NORTH CENTRAL KANSAS DUE TO ADVECTIVE PROCESSES. TEMPERATURES WILL BE ABLE TO REBOUND ABOVE FREEZING CENTRAL AND SOUTH CENTRAL KANSAS ON MONDAY...DUE TO RETURN SOUTHERLY FLOW. SOUTHEAST AND NORTHEAST KANSAS WILL REMAIN UNDER GRIP OF DEEPER...COLDER AIRMASS...THUS MAX TEMPS ONLY EXPECTED TO REACH MID TO UPPER 20S. TEMPERATURES MONDAY INTO TUESDAY WILL MODERATE DUE TO SOUTHERLY FLOW...BUT THEN ANOTHER FAST MOVING SYSTEM WILL DIVE ACROSS THE PLAINS BRINGING ANOTHER SHOT OF COLDER AIR AND POSSIBLY A CHANCE OF LIGHT SNOW OR RAIN/SNOW MIX TUESDAY AFTERNOON AND TUESDAY NIGHT. ANOTHER FAST MOVING SHORT WAVE DIVES INTO SOUTHERN PLAINS WEDNESDAY NIGHT INTO TUESDAY. FORECAST MODELS DEEPENED/INTENSIFIED THIS OPEN WAVE THE PAST FEW RUNS. DETERMINISTIC MODELS ARE SHOWING VARIABILITY IN TRACK AND DEPTH OF H5/SURFACE LOW...WHICH WILL HAVE IMPACT ON PRECIPITATION TYPE. GFS IS MORE BULLISH WITH PRECIPITATION AND EVOLVES WARM AND MOIST CONVEYOR BELT MORE SO THAN ECWMF. GFS ENSEMBLES ALL OVER THE PLACE WITH H5 EVOLUTION AND EC MEAN ENSEMBLE LOOKS RATHER ANEMIC. GIVEN UNCERTAINTY...KEPT PRECIPITATION CHANCES ON THE LOW SIDE AND DID NOT GET TOO SPECIFIC WITH PRECIPITATION TYPE. .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 335 PM CST SUN JAN 17 2016 EXTENDED PART OF THE FORECAST PERIOD INDICATES A WARMING AND DRY TREND AS H5 RIDGING BUILDS OVER INTERMOUNTAIN WEST FRIDAY AND SATURDAY. SF && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1131 PM CST SUN JAN 17 2016 VFR CONDITIONS FORECAST AT ALL SITES THROUGHOUT THE PERIOD. SURFACE RIDGE AXIS CONTINUES TO MOVE ACROSS THE AREA WITH LIGHT VARIABLE WINDS AT MOST LOCATIONS AT ONSET. WEAK RETURN FLOW DEVELOPS ON MON. FOG/STRATUS ALONG WESTERN CORRIDOR IN RETURN OF LOW LEVEL MOISTURE SEEMS UNLIKELY AT THIS POINT...BUT MAY BE A PROBLEM LATE MON NIGHT. -HOWERTON && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 9 31 23 38 / 20 0 0 30 HUTCHINSON 8 32 24 34 / 20 0 0 30 NEWTON 6 30 22 34 / 20 0 0 30 ELDORADO 7 29 22 37 / 20 0 0 40 WINFIELD-KWLD 9 31 23 42 / 20 0 0 30 RUSSELL 8 35 23 32 / 10 0 10 30 GREAT BEND 8 36 24 33 / 10 0 10 20 SALINA 6 31 21 31 / 20 0 10 30 MCPHERSON 8 31 23 33 / 20 0 10 30 COFFEYVILLE 10 29 23 45 / 40 10 0 40 CHANUTE 6 27 20 41 / 30 0 10 40 IOLA 5 26 20 40 / 30 0 0 50 PARSONS-KPPF 6 28 21 43 / 40 0 0 40 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1048 PM EST TUE JAN 19 2016 .UPDATE... ISSUED AT 1040 PM EST TUE JAN 19 2016 THE LEADING EDGE OF PRECIPITATION FROM A SYSTEM TO AFFECT THE REGION LATER TONIGHT AND INTO WEDNESDAY NIGHT HAS MOVED INTO SOUTHERN IL AND FAR WESTERN KY. THIS PRECIPITATION SHOULD CONTINUE TO SPREAD EAST OVERNIGHT AND INTO WEDNESDAY MORNING. THE 18Z NAM AND NOW THE 0Z NAM HAVE POINTED TOWARD HIGHER QPF IN THE FAR SW COMPARED TO THE PREVIOUS FORECAST. THE 0Z GFS ALSO HAS QPF THAT SHOULD BE ENTIRELY OR ALMOST ENTIRELY SNOW OF AROUND 0.40 INCHES IN WAYNE COUNTY. WITH SNOW RATIOS EXPECTED TO BE 10 TO 11 TO 1 THAT WOULD PROBABLY PUSH WAYNE COUNTY TO AT OR SLIGHTLY ABOVE THE 12 HOUR WINTER STORM WARNING CRITERIA OF 4 INCHES. WITH THIS IN MIND...WAYNE COUNTY HAS BEEN UPGRADED TO A WINTER STORM WARNING FOR 3 TO 5 INCHES OF SNOW. NEIGHBORING COUNTIES TO WANE SHOULD PICK UP AMOUNTS IN THE 2 TO 4 INCH RANGE...WITH AMOUNTS TAPERING OFF FROM THERE TO THE NORTH AND EAST DUE TO DRIER AIR IN PLACE. SOME OF THE RECENT RAP AND HRRR RUNS SUPPORT THE 0Z NAM AND 0Z GFS TO AN EXTENT ALTHOUGH THE 2Z RAP HAS HIGHER QPF FURTHER NORTH INTO THE PULASKI TO LAUREL COUNTY CORRIDOR. THE MOST RECENT HRRR IS SLIGHTLY LIGHTER WITH AM SNOW IN THE SW COUNTIES COMPARED TO A COUPLE OF EARLIER RUNS...SO OVERALL SOME UNCERTAINTY REMAINS EVEN WITH THIS SYSTEM. HOWEVER...THERE SEEMS TO BE AN UPWARD TREND IN QPF AND SNOWFALL FOR THE FAR SW THUS THE WAYNE COUNTY UPGRADE. AN UPDATED WSW AND HWO HAVE BEEN ISSUED. AS FOR THE LATE WEEK SYSTEM...THE DISTURBANCES THAT SHOULD INTERACT OR PHASE TOGETHER FOR THE EASTERN CONUS TROUGH AND LOW PRESSURE SYSTEM ARE NOW ONSHORE OF THE WESTERN U.S. OR MOVING ONSHORE AT THIS TIME. AS UPPER AIR NETWORKS BEGIN TO CAPTURE THE STRENGTH OF THESE SYSTEMS...MODEL RUNS FROM 0Z THIS MORNING AND INTO WEDNESDAY SHOULD BEGIN TO CLOSE IN WITH MORE OF A CONSENSUS. THIS SYSTEM WILL CONTINUE TO BE MONITORED AND IS ALSO BEING HIGHLIGHTED IN WEATHERSTORIES AND HWO. UPDATE ISSUED AT 810 PM EST TUE JAN 19 2016 OTHER THAN FINE TUNING THE HOURLY TEMPERATURE FORECAST FOR THE NEXT FEW HOURS...NO CHANGES ARE NEEDED AT THIS TIME. AS THE 0Z MODEL RUNS COME IN AS WELL AS THE 21Z SREF AND HRRR AND RAP RUNS WILL BE EVALUATED FOR WHETHER OR NOT QPF AND SNOW AMOUNTS MAY NEED TO INCREASED ACROSS THE LAKE CUMBERLAND REGION. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 406 PM EST TUE JAN 19 2016 CURRENT CONDITIONS ACROSS THE AREA FEATURE CLOUD COVER ON THE INCREASE IN WESTERN KENTUCKY ASSOCIATED WITH A DEVELOPING SYSTEM. MEANWHILE...IN EASTERN KENTUCKY CLOUD COVER IS DISSIPATING AS NORTHWEST UPSLOPE FLOW DECREASES AS THE CENTER OF THE ARCTIC HIGH HAS MOVED OVER THE AREA. THUS HAVE CLEARED SKY COVER AND SHUT OFF THE FLURRIES ACROSS THE AREA AS WELL. AFTER 00Z TONIGHT...SKIES WILL CLOUD UP AGAIN AS THE NEXT SYSTEM MOVES THROUGH THE BLUEGRASS. PRECIP WILL BEGIN TO MOVE INTO THE AREA AFTER 08Z. MODEL TRENDS HAVE KEPT THIS FEATURE WITH A GOOD AMOUNT OF LIFT AND MOISTURE. TRENDS HAVE ALSO TAKEN THE MOST AMOUNT OF MOISTURE TO THE SOUTH INTO CENTRAL KY AND THEN INTO TN JUST CLIPPING WETS OF THE I-75 CORRIDOR. THIS REGION WILL LIKELY SEE THE MOST AMOUNT OF SNOW FROM THIS FEATURE. SURFACE TEMPS AS THIS FEATURE MOVES IN WILL JUST BE RECOVERING FROM THE ARCTIC AIR MASS THAT HAS JUST EVACUATED THE AREA. THUS PRECIP WILL BEGIN AS SNOW FOR THIS SYSTEM. WARMEST TEMPS THOUGH WILL BE IN THE SOUTH WITH SOUTHERLY FLOW SETTING UP AHEAD OF THE FRONT. THUS...SNOW RATIOS WILL BE SLIGHTLY LOWER THAN THE NORTH AS THIS FEATURE MOVES INTO THE AREA. SNOW WILL CONTINUE ACROSS EASTERN KENTUCKY THROUGH THE DAY AND BECOME MODERATE TO EVEN HEAVY AT TIMES. HIGH RATIOS TO THE NORTH WILL MAKE FOR SNOWFALL AMOUNTS IN THE 1 TO 2 INCH RANGE BUT MORE MOISTURE IN THE SOUTH WILL MAKE FOR 2 TO 3+ AMOUNTS DESPITE THE LOWER SNOW RATIOS. THE OTHER CONCERN FOR SNOW AMOUNTS WITH THIS FEATURE WILL BE THE PROGRESSIVE FLOW AS THIS SYSTEM MOVES THROUGH. AS THE SYSTEM LOSES A BIT OF MOISTURE MOVING INTO THE AREA...THE DEPTH OF THE MOISTURE LESSENS QUITE QUICKLY BY WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. DUE TO THIS MUCH OF THE SNOW WILL CHANGE OVER TO FREEZING DRIZZLE HEADING INTO WEDNESDAY EVENING AND WEDNESDAY NIGHT. IN FACT...A GLAZE OF ICE IS POSSIBLE IN SOME AREAS...ESPECIALLY IN THE SOUTH...WHERE UP TO 0.05 HUNDREDTHS ARE POSSIBLE. THIS SET UP MAY ALSO TAKE AWAY FROM SOME OF THE SNOWFALL POTENTIAL IN THE SOUTH. THUS...WILL KEEP THE WINTER WEATHER ADVISORY OUT FOR THE ENTIRE AREA FROM TOMORROW MORNING AND THROUGH THURSDAY NIGHT. HEADING INTO WEDNESDAY NIGHT...THE SYSTEM EXITS THE AREA AS THE LAST OF THE LOW LEVEL MOISTURE EXITS AS WELL. THIS WILL BRING AN END TO THE FREEZING DRIZZLE THREAT BEFORE THE NEXT FEATURE BEGINS TO IMPACT THE AREA MOVING IN FROM THE SOUTH. IN FACT...WE WILL HAVE A BRIEF BREAK IN THE PRECIP BY THURSDAY MORNING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 406 PM EST TUE JAN 19 2016 COMPLICATED FORECAST IN THE LONG TERM WITH LOTS OF ATTENTION ON A POSSIBLE MAJOR WINTER STORM IN THE THURSDAY NIGHT THROUGH SATURDAY TIME RANGE. AS OUR MIDWEEK WINTER SYSTEM PASSES TO OUR EAST...TEMPERATURES ALOFT WILL BE ON THE RISE AS A WARM FRONT AT THE SURFACE MOVES UP THE GREAT VALLEY OF EAST TENNESSEE VALLEY. THIS WILL SEND PRECIPITATION BACK NORTH INTO THE AREA LATE THURSDAY INTO THURSDAY NIGHT. THERMAL PROFILE IS TRICKY BUT P-TYPE IS EXPECTED TO BE MOSTLY RAIN ACROSS THE SOUTH BUT A MIX OF RAIN...SNOW AND FREEZING RAIN ALONG AND NORTH OF THE HAL ROGERS PARKWAY THURSDAY NIGHT...AND PROBABLY ALL SNOW OR A MIX OF FREEZING RAIN AND SNOW FROM I-64 NORTH. FORECAST MODELS THEN DIVERGE INTO FRIDAY BUT THE PRESENCE OF AN INVERTED TROUGH EXTENDING UP THE GREAT VALLEY OF EAST TENNESSEE INTO THE CUMBERLAND VALLEY WOULD SUPPORT A SCENARIO WHERE THE WARM NOSE ALOFT EDGES FURTHER NORTH CAUSING PRECIP TO MIX WITH OR CHANGE TO RAIN PERHAPS AS FAR NORTH AS THE MOUNTAIN PARKWAY AND POSSIBLY EVEN I-64. THE NORTHWARD EXTEND TO THE CHANGE TO RAIN DEPENDS GREATLY ON THE STRENGTH AND TRACK OF THE SURFACE LOW...WITH WHICH THERE IS JUST A LOT OF UNCERTAINTY DUE TO MODEL DIFFERENCES SO TRIED TO PAINT WITH A BROAD BRUSH AS FAR AS THE ACTUAL P-TYPE FORECAST GOES RIGHT NOW THROUGH THE DAY FRIDAY. SO...WHILE THE ACTUAL WEATHER YOU WILL SEE REMAINS UNCERTAIN THURSDAY NIGHT AND FRIDAY...PLAN TO BE IMPACTED BY THE WEATHER IN SOME FORM OR FASHION IF YOU HAVE TRAVEL PLANS AND MONITOR FORECASTS AS OUR CONFIDENCE IN THE DETAILS IMPROVES OVER THE NEXT DAY OR SO. MODELS ARE FAIRLY CONSISTENT THAT COLDER AIR WILL WRAP IN BEHIND THE DEPARTING SURFACE LOW FRIDAY EVENING CHANGING ALL PRECIP TO SNOW QUICKLY FROM NORTHWEST TO SOUTHEAST. THE SNOW WILL LIKELY CONTINUE THROUGH AT LEAST SATURDAY MORNING...AND POSSIBLY EVEN INTO SATURDAY NIGHT AS THE UPPER LOW IS SLOW TO PIVOT THROUGH. THE POTENTIAL EXISTS FOR SEVERAL INCHES OF SNOW. THE REMAINDER OF THE EXTENDED WILL FEATURE WARMING TEMPS... ALTHOUGH POTENTIAL SNOW COVER WILL HAVE A YET TO BE DETERMINED INFLUENCE THERE. ANOTHER SYSTEM IS PROGGED TO DEVELOP OVER THE SOUTHERN PLAINS AND THEN MOVE NORTHEAST SPREADING ANOTHER CHANCE FOR PRECIPITATION ACROSS THE AREA AS EARLY AS MONDAY. THIS SHOULD BE RAIN AS IT APPEARS RIGHT NOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 735 PM EST TUE JAN 19 2016 VFR WILL CONTINUE FOR ABOUT THE FIRST 6 HOURS TONIGHT. LATER TONIGHT...A COLD FRONT WILL BRING SNOWFALL TO THE FAR SOUTHWEST BY 09Z...SPREADING ACROSS THE ENTIRE AREA BY 16Z. THIS WILL THEN RESULT IN DETERIORATION INTO MVFR AND THEN IFR AND POSSIBLY NEAR OR BELOW AIRPORT MINS AT TIMES FOR VIS IN THE FALLING SNOW AND AND CIGS DURING SNOW AND AFTER IT DEPARTS AND TAPERS TO DRIZZLE OR FREEZING DRIZZLE. WINDS WILL BE LIGHT TO NEAR CALM THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 7 AM EST THURSDAY FOR KYZ052-060-088-104-106>110-112-113-115-117>120. WINTER WEATHER ADVISORY FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY FOR KYZ044-050-051-058-059-068-069-079-080-084>087-111-114-116. WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY FOR KYZ083. && $$ UPDATE...JP SHORT TERM...SHALLENBERGER LONG TERM...ABE AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
817 PM EST TUE JAN 19 2016 .UPDATE... ISSUED AT 810 PM EST TUE JAN 19 2016 OTHER THAN FINE TUNING THE HOURLY TEMPERATURE FORECAST FOR THE NEXT FEW HOURS...NO CHANGES ARE NEEDED AT THIS TIME. AS THE 0Z MODEL RUNS COME IN AS WELL AS THE 21Z SREF AND HRRR AND RAP RUNS WILL BE EVALUATED FOR WHETHER OR NOT QPF AND SNOW AMOUNTS MAY NEED TO INCREASED ACROSS THE LAKE CUMBERLAND REGION. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 406 PM EST TUE JAN 19 2016 CURRENT CONDITIONS ACROSS THE AREA FEATURE CLOUD COVER ON THE INCREASE IN WESTERN KENTUCKY ASSOCIATED WITH A DEVELOPING SYSTEM. MEANWHILE...IN EASTERN KENTUCKY CLOUD COVER IS DISSIPATING AS NORTHWEST UPSLOPE FLOW DECREASES AS THE CENTER OF THE ARCTIC HIGH HAS MOVED OVER THE AREA. THUS HAVE CLEARED SKY COVER AND SHUT OFF THE FLURRIES ACROSS THE AREA AS WELL. AFTER 00Z TONIGHT...SKIES WILL CLOUD UP AGAIN AS THE NEXT SYSTEM MOVES THROUGH THE BLUEGRASS. PRECIP WILL BEGIN TO MOVE INTO THE AREA AFTER 08Z. MODEL TRENDS HAVE KEPT THIS FEATURE WITH A GOOD AMOUNT OF LIFT AND MOISTURE. TRENDS HAVE ALSO TAKEN THE MOST AMOUNT OF MOISTURE TO THE SOUTH INTO CENTRAL KY AND THEN INTO TN JUST CLIPPING WETS OF THE I-75 CORRIDOR. THIS REGION WILL LIKELY SEE THE MOST AMOUNT OF SNOW FROM THIS FEATURE. SURFACE TEMPS AS THIS FEATURE MOVES IN WILL JUST BE RECOVERING FROM THE ARCTIC AIR MASS THAT HAS JUST EVACUATED THE AREA. THUS PRECIP WILL BEGIN AS SNOW FOR THIS SYSTEM. WARMEST TEMPS THOUGH WILL BE IN THE SOUTH WITH SOUTHERLY FLOW SETTING UP AHEAD OF THE FRONT. THUS...SNOW RATIOS WILL BE SLIGHTLY LOWER THAN THE NORTH AS THIS FEATURE MOVES INTO THE AREA. SNOW WILL CONTINUE ACROSS EASTERN KENTUCKY THROUGH THE DAY AND BECOME MODERATE TO EVEN HEAVY AT TIMES. HIGH RATIOS TO THE NORTH WILL MAKE FOR SNOWFALL AMOUNTS IN THE 1 TO 2 INCH RANGE BUT MORE MOISTURE IN THE SOUTH WILL MAKE FOR 2 TO 3+ AMOUNTS DESPITE THE LOWER SNOW RATIOS. THE OTHER CONCERN FOR SNOW AMOUNTS WITH THIS FEATURE WILL BE THE PROGRESSIVE FLOW AS THIS SYSTEM MOVES THROUGH. AS THE SYSTEM LOSES A BIT OF MOISTURE MOVING INTO THE AREA...THE DEPTH OF THE MOISTURE LESSENS QUITE QUICKLY BY WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. DUE TO THIS MUCH OF THE SNOW WILL CHANGE OVER TO FREEZING DRIZZLE HEADING INTO WEDNESDAY EVENING AND WEDNESDAY NIGHT. IN FACT...A GLAZE OF ICE IS POSSIBLE IN SOME AREAS...ESPECIALLY IN THE SOUTH...WHERE UP TO 0.05 HUNDREDTHS ARE POSSIBLE. THIS SET UP MAY ALSO TAKE AWAY FROM SOME OF THE SNOWFALL POTENTIAL IN THE SOUTH. THUS...WILL KEEP THE WINTER WEATHER ADVISORY OUT FOR THE ENTIRE AREA FROM TOMORROW MORNING AND THROUGH THURSDAY NIGHT. HEADING INTO WEDNESDAY NIGHT...THE SYSTEM EXITS THE AREA AS THE LAST OF THE LOW LEVEL MOISTURE EXITS AS WELL. THIS WILL BRING AN END TO THE FREEZING DRIZZLE THREAT BEFORE THE NEXT FEATURE BEGINS TO IMPACT THE AREA MOVING IN FROM THE SOUTH. IN FACT...WE WILL HAVE A BRIEF BREAK IN THE PRECIP BY THURSDAY MORNING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 406 PM EST TUE JAN 19 2016 COMPLICATED FORECAST IN THE LONG TERM WITH LOTS OF ATTENTION ON A POSSIBLE MAJOR WINTER STORM IN THE THURSDAY NIGHT THROUGH SATURDAY TIME RANGE. AS OUR MIDWEEK WINTER SYSTEM PASSES TO OUR EAST...TEMPERATURES ALOFT WILL BE ON THE RISE AS A WARM FRONT AT THE SURFACE MOVES UP THE GREAT VALLEY OF EAST TENNESSEE VALLEY. THIS WILL SEND PRECIPITATION BACK NORTH INTO THE AREA LATE THURSDAY INTO THURSDAY NIGHT. THERMAL PROFILE IS TRICKY BUT P-TYPE IS EXPECTED TO BE MOSTLY RAIN ACROSS THE SOUTH BUT A MIX OF RAIN...SNOW AND FREEZING RAIN ALONG AND NORTH OF THE HAL ROGERS PARKWAY THURSDAY NIGHT...AND PROBABLY ALL SNOW OR A MIX OF FREEZING RAIN AND SNOW FROM I-64 NORTH. FORECAST MODELS THEN DIVERGE INTO FRIDAY BUT THE PRESENCE OF AN INVERTED TROUGH EXTENDING UP THE GREAT VALLEY OF EAST TENNESSEE INTO THE CUMBERLAND VALLEY WOULD SUPPORT A SCENARIO WHERE THE WARM NOSE ALOFT EDGES FURTHER NORTH CAUSING PRECIP TO MIX WITH OR CHANGE TO RAIN PERHAPS AS FAR NORTH AS THE MOUNTAIN PARKWAY AND POSSIBLY EVEN I-64. THE NORTHWARD EXTEND TO THE CHANGE TO RAIN DEPENDS GREATLY ON THE STRENGTH AND TRACK OF THE SURFACE LOW...WITH WHICH THERE IS JUST A LOT OF UNCERTAINTY DUE TO MODEL DIFFERENCES SO TRIED TO PAINT WITH A BROAD BRUSH AS FAR AS THE ACTUAL P-TYPE FORECAST GOES RIGHT NOW THROUGH THE DAY FRIDAY. SO...WHILE THE ACTUAL WEATHER YOU WILL SEE REMAINS UNCERTAIN THURSDAY NIGHT AND FRIDAY...PLAN TO BE IMPACTED BY THE WEATHER IN SOME FORM OR FASHION IF YOU HAVE TRAVEL PLANS AND MONITOR FORECASTS AS OUR CONFIDENCE IN THE DETAILS IMPROVES OVER THE NEXT DAY OR SO. MODELS ARE FAIRLY CONSISTENT THAT COLDER AIR WILL WRAP IN BEHIND THE DEPARTING SURFACE LOW FRIDAY EVENING CHANGING ALL PRECIP TO SNOW QUICKLY FROM NORTHWEST TO SOUTHEAST. THE SNOW WILL LIKELY CONTINUE THROUGH AT LEAST SATURDAY MORNING...AND POSSIBLY EVEN INTO SATURDAY NIGHT AS THE UPPER LOW IS SLOW TO PIVOT THROUGH. THE POTENTIAL EXISTS FOR SEVERAL INCHES OF SNOW. THE REMAINDER OF THE EXTENDED WILL FEATURE WARMING TEMPS... ALTHOUGH POTENTIAL SNOW COVER WILL HAVE A YET TO BE DETERMINED INFLUENCE THERE. ANOTHER SYSTEM IS PROGGED TO DEVELOP OVER THE SOUTHERN PLAINS AND THEN MOVE NORTHEAST SPREADING ANOTHER CHANCE FOR PRECIPITATION ACROSS THE AREA AS EARLY AS MONDAY. THIS SHOULD BE RAIN AS IT APPEARS RIGHT NOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 735 PM EST TUE JAN 19 2016 VFR WILL CONTINUE FOR ABOUT THE FIRST 6 HOURS TONIGHT. LATER TONIGHT...A COLD FRONT WILL BRING SNOWFALL TO THE FAR SOUTHWEST BY 09Z...SPREADING ACROSS THE ENTIRE AREA BY 16Z. THIS WILL THEN RESULT IN DETERIORATION INTO MVFR AND THEN IFR AND POSSIBLY NEAR OR BELOW AIRPORT MINS AT TIMES FOR VIS IN THE FALLING SNOW AND AND CIGS DURING SNOW AND AFTER IT DEPARTS AND TAPERS TO DRIZZLE OR FREEZING DRIZZLE. WINDS WILL BE LIGHT TO NEAR CALM THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 7 AM EST THURSDAY FOR KYZ052-060-088-104-106>110-112-113-115-117>120. WINTER WEATHER ADVISORY FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY FOR KYZ044-050-051-058-059-068-069-079-080-083>087-111-114-116. && $$ UPDATE...JP SHORT TERM...SHALLENBERGER LONG TERM...ABE AVIATION...JP
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
642 PM CST TUE JAN 19 2016 .UPDATE... Issued at 642 PM CST TUE JAN 19 2016 Watching very closely the precipitation across SEMO, where light freezing rain/drizzle has been reported and has caused very dangerous travel conditions. Issued a SPS, and highlighted it more strongly in the social media realm. May take a look at the WSW. Thing is, as the upper system moves closer and precip increases, precip loading, top down cooling will start to erode the "warm" layer, or at least suppress it toward the MO/AR border, and transition precip to mainly sleet and snow early this evening. So for now, will handle this as a very short term event, and not complicate the overall message. Will make some minor changes to the grid forecast in this area. The RAP thermal depictions support this approach. CN && .SHORT TERM...(This evening through Wednesday night) Issued at 131 PM CST TUE JAN 19 2016 With 12z model suite painting low end 4 tenths qpf, and high end 6 tenths, and ratios low end 12 to 1, and high end 17 to 1, per collab with WPC and adjacent WFO`s...have upgraded to warn all areas for broad 3 to 5 inch expectation. More specifically, some heavier snow could paint a swath of locally higher amounts (depending upon the solution)... and higher liquid to snow ratios in cold low to mid 20s air... could potentially yield a 6+ inch swath. The main threat area for this is roughly latitudinally along the Ohio river thru the heart of the FA and southward toward the AR/TN borders. On the flip side, if more scant amounts of qpf across our north occur (visa vi the GFS), and using a less gracious LSR, we could see lesser 2 to 2.5" totals along the I-64 corridor from Mount Vernon IL into southwest IN. In summary, broad 3 to 5 inch totals expected snow/sleet. Some chance slightly lower 2 inch totals possible north, and higher 6+ inch totals a possibility across south-central ptns. Cant rule out some hundredths of freezing rain across mainly srn border counties, but focusing mostly on snow/sleet potential given consistency of colder/further southern/eastern track. Factors at play for a little more sleet vs snow include 3 to 6K foot depth of warm nose ranging from -1C to +2C for at times 3 to 6 hrs of pcpn time period. This skews totals a little toward lower end of aforementioned ratios, if it plays out. Adjusted start time of WSW to 00z, given accumulating snows could be ongoing at 03z for farthest western portions of SEMO/SWIL. End time maintained at 18Z, but effectively ends at 15Z for all but farthest southeastern counties...as pcpn shuts off sharply northwest to southeast thru the morning hours Wednesday. .LONG TERM...(Thursday through Tuesday) Issued at 255 PM CST TUE JAN 19 2016 Another messy round of winter weather will follow our mid week event. Models are in good agreement showing a low pressure system centered over central Mississippi at 00z Friday. Being on the cold side of the low along with the expected snow pack across our region, a majority of the precipitation Thursday into Friday will be freezing or frozen. Precipitation is expected to start as a mix of freezing rain, sleet and snow across all but our north and northwest counties, where precipitation should begin as snow and remain snow through the event. Models imply temperatures briefly reaching 33 to 37 degrees across most areas by Thursday afternoon, which would switch us to rain. However confidence is a bit low on how much warming we can get, so kept most areas as a mix except for a portion of west Kentucky and southeast Missouri. For Thursday night, any areas that begin as a mix will switch to all snow by midnight as the low moves off to our southeast overnight. The snow will continue into Friday, tapering off from west to east Friday afternoon into Friday night. Right now 1 to 3 inches of snow is possible, but amounts are questionable at this point and will greatly depend on how warm our surface temperatures can get. The weekend will be dry as high pressures moves across the Gulf of Mexico. Temperatures will reach the middle 30s Saturday, and around 40 degrees Sunday. Another round of precipitation will return for Monday. Models take a surface low right over the PAH forecast area late Monday into Monday night. Rain is possible Monday, then as the low moves overhead and east of us, rain will mix with and change over to snow Monday night. Rain or snow will then be possible for Tuesday into Tuesday night, but we will have to continue to watch the track of the low to see just how warm or cold we will be for the beginning of the work week. && .AVIATION... Issued at 537 PM CST TUE JAN 19 2016 Downward progression of ceilings and visibilities from VFR to MVFR and IFR will take place through 06z for all WFO PAH TAF sites with the oncoming snow. A very brief, less than an hour period of light sleet (PL) and freezing rain (ZR) at the onset at KCGI and KPAH, but the duration and likelihood of these precipitation types should lessen markedly as the night goes on. Although the moist layer will be very shallow by noon Wednesday, kept an broken/overcast layer in place through the afternoon. && .PAH Watches/Warnings/Advisories... IL...Winter Storm Warning until noon CST Wednesday for ILZ075>078- 080>094. MO...Winter Storm Warning until noon CST Wednesday for MOZ076-086-087- 100-107>112-114. IN...Winter Storm Warning until noon CST Wednesday for INZ081-082- 085>088. KY...Winter Storm Warning until noon CST Wednesday for KYZ001>022. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
959 PM CST TUE JAN 19 2016 .DISCUSSION... A LINE OF BROKEN CONVECTION HAS DEVELOPED OVER THE LAST COUPLE OF HRS JUST AHEAD OF A COLD FRONT THAT IS ENTERING THE NWRN ZONES. 00Z KSHV RAOB SHOWS A PRONOUNCED DRY LAYER BETWEEN 850-560 MB...INDICATIVE OF SHOW MID LVL DRY SLOTTING IN THE WAKE OF A DEPARTING SHORTWAVE TROUGH PER LATEST WV LOOPS. SOME ADDITIONAL MID/UPPER LVL MOISTURE MOVING INTO THE SRN PLAINS COULD HELP THE ATMOSPHERE MOISTEN FROM THE TOP DOWN IF IT ARRIVES BEFORE THE FRONT. OTHERWISE...PRECIP WILL REMAIN SPOTTY AND SCATTERED AT BEST. RAIN CHANCES MIGHT BE A BIT HIGHER ACROSS SRN AR DURING THE EARLY MORNING HRS AS VERTICAL ASCENT MIGHT BE SLIGHTLY HIGHER DUE TO THE PROXIMITY OF A SFC LOW AND THE UPPER TROUGH AXIS. QUITE A FEW CHANGES WERE MADE IN THE GRIDS DURING THE FIRST 72 HRS OF THE FCST BASED ON THE LATEST HRRR AND THE 00Z NAM. BIGGEST CHANGES WERE MADE TO POPS AND TEMPS. UPDATED PRODUCTS WILL BE SENT SHORTLY. /09/ && .PREV DISCUSSION... /ISSUED 540 PM CST TUE JAN 19 2016/ AVIATION... CONDITIONS TO DETERIORATE OVERNIGHT AS A COLD FRONT MOVES ACROSS THE AREA. CEILINGS TO BECOME MVFR AHEAD OF THE FRONT FOLLOWED BY AN INCREASE IN COVERAGE OF RAIN SHOWERS AFTER 20/06Z. WINDS TO BECOME NORTHWEST 5 TO 10 KNOTS BEHIND THE FRONT ACROSS MOST AREAS BY DAYBREAK. OTHERWISE...IFR CEILINGS AND VISIBILITIES BETWEEN 20/12Z-20/16Z TO GRADUALLY IMPROVE THROUGHOUT THE DAY. /05/ && .PRELIMINARY POINT TEMPS/POPS... SHV 47 56 50 62 / 40 20 40 50 MLU 48 57 49 65 / 30 40 40 70 DEQ 39 49 40 53 / 40 10 50 60 TXK 41 50 45 56 / 50 10 50 60 ELD 43 52 44 58 / 50 40 50 70 TYR 41 53 49 60 / 40 10 40 40 GGG 43 54 50 61 / 40 10 40 50 LFK 47 59 54 65 / 30 20 30 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 09
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
552 PM EST MON JAN 18 2016 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 410 PM EST MON JAN 18 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM THE ERN LAKES INTO NRN NEW ENGLAND WITH A SHORTWAVE TROUGH EXTENDING NW TO NEAR LAKE SUPERIOR. AT THE SFC...A LAKES AGGREGATE TROUGH EXTENDED FROM LAKE HURON INTO SRN LAKE SUPERIOR. MULTIPLE WIND PARALLEL LES BANDS WITH NW ARCTIC FLOW CONTINUED. 850 MB TEMPS AROUND -23C PROVIDED PLENTIFUL INSTABILITY WITH LAKE INDUCED CAPES INTO THE 500-750 J/KG. THE MID LEVEL SHRTWV AND ASSOCIATED 700-300 MB QVECTOR CONV HAS ALSO HELPED BOOST INVERSION/EQUILIBRIUM HEIGHTS THIS AFTERNOON. VIS LOOP...SFC OBS AND WEB CAMS SUGGEST THE HEAVIER LES WAS OVER THE ERN CWA...IN CLOSER PROXIMITY TO THE SHRTWV AND DOWNSTREAM FROM THE LONGEST FETCH. TONIGHT...THE HIGH RES MODELS SUGGEST THAT LOW LEVEL WINDS WILL VEER SLIGHTLY IN THE WAKE OF THE SHRTWV...HELPING TO PUSH THE MORE PROMINENT LES BANDS INTO CNTRL AND WRN ALGER COUNTY. WITH ADDITIONAL SNOWFALL AMOUNTS IN THE 3 TO 7 INCH RANGE EXPECTED...THE LES WARNING WAS EXTENDED (TIL 12Z) FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WITH AN THE ADVY INTO SRN SCHOOLCRAFT ALSO EXTENDED TIL 06Z. OVER THE WEST...INVERSION HEIGHTS DROP OFF TO AROUND 4K FT THIS EVENING WHICH SHOULD LIMIT LES INTENSITY WITH ADDITIONAL SNOWFALL AMOUNTS TO ADVY AMOUNTS IN THE 2 TO 5 INCH RANGE OR LESS. THE STRONGER LOW LEVEL CONV FROM ONTONAGON EASTWARD SHOULD ALSO SAG TO THE SOUTH THIS EVENING. TUE...LES SHOULD CONTINUE TO DIMINISH WITH INVERSION HEIGHTS FALLING TO 3K-4K FT AND WINDS BACKING ACYC WRLY AS A SFC RIDGE BUILDS FROM THE UPPER MS VALLEY INTO THE WRN LAKES. TEMPS WILL ALSO MODERATE WITH HIGHS FROM THE LOWER TEENS WEST TO AROUND 20 EAST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 324 PM EST MON JAN 18 2016 THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS SFC WINDS SHIFT TO A MORE S-SW DIRECTION. A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH 1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C. LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS 850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS. THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 552 PM EST MON JAN 18 2016 AT KIWD...EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A RETURN TO VFR CONDITIONS TUE AFTERNOON AS WINDS BACK TO THE SW. AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR CONDITIONS IN LAKE EFFECT SNOW INTO THIS EVENING. EXPECT SOME IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS DIMINISH. HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN PREVAILING IFR CONDITIONS THROUGH TUE AFTERNOON. AT KSAW...EXPECT MVFR THIS EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 410 PM EST MON JAN 18 2016 EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED WILL ALSO END EARLY THIS EVENING. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001>003- 084. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ014. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ263>266. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 PM EST MON JAN 18 2016 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 410 PM EST MON JAN 18 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM THE ERN LAKES INTO NRN NEW ENGLAND WITH A SHORTWAVE TROUGH EXTENDING NW TO NEAR LAKE SUPERIOR. AT THE SFC...A LAKES AGGREGATE TROUGH EXTENDED FROM LAKE HURON INTO SRN LAKE SUPERIOR. MULTIPLE WIND PARALLEL LES BANDS WITH NW ARCTIC FLOW CONTINUED. 850 MB TEMPS AROUND -23C PROVIDED PLENTIFUL INSTABILITY WITH LAKE INDUCED CAPES INTO THE 500-750 J/KG. THE MID LEVEL SHRTWV AND ASSOCIATED 700-300 MB QVECTOR CONV HAS ALSO HELPED BOOST INVERSION/EQUILIBRIUM HEIGHTS THIS AFTERNOON. VIS LOOP...SFC OBS AND WEB CAMS SUGGEST THE HEAVIER LES WAS OVER THE ERN CWA...IN CLOSER PROXIMITY TO THE SHRTWV AND DOWNSTREAM FROM THE LONGEST FETCH. TONIGHT...THE HIGH RES MODELS SUGGEST THAT LOW LEVEL WINDS WILL VEER SLIGHTLY IN THE WAKE OF THE SHRTWV...HELPING TO PUSH THE MORE PROMINENT LES BANDS INTO CNTRL AND WRN ALGER COUNTY. WITH ADDITIONAL SNOWFALL AMOUNTS IN THE 3 TO 7 INCH RANGE EXPECTED...THE LES WARNING WAS EXTENDED (TIL 12Z) FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WITH AN THE ADVY INTO SRN SCHOOLCRAFT ALSO EXTENDED TIL 06Z. OVER THE WEST...INVERSION HEIGHTS DROP OFF TO AROUND 4K FT THIS EVENING WHICH SHOULD LIMIT LES INTENSITY WITH ADDITIONAL SNOWFALL AMOUNTS TO ADVY AMOUNTS IN THE 2 TO 5 INCH RANGE OR LESS. THE STRONGER LOW LEVEL CONV FROM ONTONAGON EASTWARD SHOULD ALSO SAG TO THE SOUTH THIS EVENING. TUE...LES SHOULD CONTINUE TO DIMINISH WITH INVERSION HEIGHTS FALLING TO 3K-4K FT AND WINDS BACKING ACYC WRLY AS A SFC RIDGE BUILDS FROM THE UPPER MS VALLEY INTO THE WRN LAKES. TEMPS WILL ALSO MODERATE WITH HIGHS FROM THE LOWER TEENS WEST TO AROUND 20 EAST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 324 PM EST MON JAN 18 2016 THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS SFC WINDS SHIFT TO A MORE S-SW DIRECTION. A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH 1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C. LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS 850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS. THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 110 PM EST MON JAN 18 2016 AT KIWD...WINDS VEERING MORE NW LATE THIS AFTERNOON WILL LOWER CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A RETURN TO VFR CONDITIONS TUE MORNING AS WINDS BACK TO THE SW. AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY INTO THIS EVENING. EXPECT SOME IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS DIMINISH. HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN PREVAILING IFR CONDITIONS THROUGH TUE MORNING. AT KSAW...EXPECT MAINLY CIGS NEAR 3K FT...BORDERLINE MVFR...THIS AFTERNOON BUT THEN EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 410 PM EST MON JAN 18 2016 EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED WILL ALSO END EARLY THIS EVENING. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001>003- 084. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ014. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ263>266. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
350 PM EST MON JAN 18 2016 .DISCUSSION... LAKE EFFECT SNOW SHOWERS WILL HOLD WITH SCATTERED TO NUMEROUS COVERAGE AND LIGHT TO MODERATE INTENSITY FOR THE REST OF THE AFTERNOON THROUGH MID EVENING. THE MOST RECENT RAP SOUNDINGS INDICATE CONVECTIVE DEPTH SETTLING STEADILY BELOW 5000 FT BETWEEN 21Z AND 03Z BUT WITH NEARLY DRY ADIABATIC LAPSE RATE AND HIGH ICE SUPERSATURATION WITHIN THE CLOUD LAYER FOR HEALTHY GROWTH OF DENDRITES. THAT BEING SAID...SURFACE DEWPOINT AROUND -10F REPORTED UPSTREAM OF LAKE MICHIGAN HAS TO BE CONSIDERED A LIMITING FACTOR FOR LAKE INDUCED CONVECTIVE POTENTIAL THIS FAR EAST. ON THE POSITIVE SIDE...MID TO LATE AFTERNOON SURFACE OBSERVATIONS ON THIS SIDE OF THE LAKE CONTINUE TO ADVERTISE GUSTY WEST FLOW WITH A GREATER AMOUNT OF CONVERGENCE DOWN WIND OF LAKE MICHIGAN THAN WOULD NORMALLY BE EXPECTED IN WELL MIXED MID AFTERNOON CONDITIONS. THIS WILL KEEP COVERAGE WITH BETTER INTENSITY FOCUSED GENERALLY ALONG AND SOUTH OF THE I-96 TO I-94 CORRIDOR. FACTORING IN THE DRY NATURE OF THE ARCTIC AIR AND STEADILY SHRINKING CONVECTIVE DEPTH...EXPECT ACCUMULATION LIMITED TO LESS THAN AN INCH EVEN WITH NUMEROUS COVERAGE AND/OR A STREAMER OF GREATER FOCUSED BANDING AT TIMES BEFORE DIMINISHING TOWARD MIDNIGHT. THE UPPER LEVEL TROUGH WILL SWING SOUTH OF LOWER MICHIGAN SHORTLY AFTER MIDNIGHT AND WILL SHUT DOWN LAKE EFFECT PRODUCTION. STRONG SUBSIDENCE TRAILING THE UPPER TROUGH AND PRECEDING THE RIDGE AXIS WILL ALSO SUPPORT A CLEARING TREND MUCH LIKE WHAT OCCURRED EARLY THIS MORNING. THIS WILL ALLOW ANOTHER ROUND OF SINGLE DIGIT MIN TEMPS OUTSIDE OF METRO DETROIT AND MAINTAIN WIND CHILL NEAR 10 BELOW AT TIMES THROUGH TUESDAY MORNING. FORECAST CONCERNS WILL THEN BE REDUCED TO CLOUD AND TEMPERATURE TRENDS DURING THE REST OF TUESDAY AND TUESDAY NIGHT. BACKING LOW LEVEL FLOW WILL DIRECT REMAINING LAKE EFFECT CLOUDS MAINLY INTO THE TRI CITIES BEFORE HIGH PRESSURE BUILDS OVER THE REGION BY EVENING. LIGHTER WIND WILL MAKE MAX TEMPS IN THE LOWER 20S EASIER TO TAKE COMPARED TO RECENT DAYS. BENIGN CONDITIONS WILL CONTINUE THROUGH TUESDAY NIGHT AS HIGH CLOUDS THICKEN AND LOWER IN ADVANCE OF THE NEXT LOW PRESSURE SYSTEM. THE NEW MODEL PACKAGE IS IN GOOD AGREEMENT HOLDING OFF SNOW UNTIL WEDNESDAY MORNING...MAINLY AFTER THE MORNING DRIVE...AND THEN LEAVING UP TO AN INCH OF ACCUMULATION BEFORE ENDING BY MIDNIGHT WEDNESDAY NIGHT. EXPECT THIS TO BE MOSTLY A MID LEVEL ISENTROPIC LIFT DRIVEN EVENT AS MODEL DEPICTIONS OF THE 500 MB HEIGHT FIELD SHOW CONSOLIDATION OF SHORT WAVES IN THE FLOW BUT WITH FRAGMENTED DYNAMIC SUPPORT IN TERMS OF DCVA. THE LOW LEVEL FRONTAL ZONE IS ALSO LOCATED WELL SOUTH INTO THE OHIO AND TENNESSEE VALLEYS JUDGING BY 1000-850 MB THICKNESS. THIS DOES NOT PREVENT ADEQUATE MOISTURE FROM REACHING THIS FAR NORTH AS SPECIFIC HUMIDITY AVERAGES 1-2 G/KG UP TO 700 MB OVER LOWER MICHIGAN. IT DOES INDICATE THE SHALLOW AND STABLE NATURE OF THE SYSTEM RELATIVE ISENTROPIC LIFT. AS MENTIONED IN THE PREVIOUS DISCUSSION...MODEL SOUNDINGS DO INDICATE A DEEP ISOTHERMAL PROFILE WITHIN THE DGZ BELOW 600 MB WHICH WILL GIVE A BOOST TO SNOW RATIO AND POTENTIAL OVERACHIEVEMENT. THE COLLABORATED QPF ADJUSTMENTS MADE IN THE PREVIOUS FORECAST CYCLE ARE THUS PRESERVED FOR THIS PACKAGE. EXTENDED THURSDAY THROUGH TUESDAY... AS WEDNESDAY`S WAVE OF LOW PRESSURE EXITS THE REGION...A SLIGHT CHANCE OF SNOW SHOWERS WILL REMAIN IN THE FORECAST THROUGH EARLY THURSDAY MORNING. BRIEF HIGH PRESSURE BUILDS OVER THE AREA DURING THE DAY ON THURSDAY. THIS HIGH PRESSURE IS EXPECTED TO PRODUCE A DECENT DRY DAY WITH MOSTLY TO PARTLY CLOUDY SKIES OVER THE WHOLE OF SOUTHEAST MICHIGAN. AN UPPER LEVEL TROUGH SWINGS ACROSS THE NORTHERN THUMB AREAS ON FRIDAY...GENERATING ANOTHER WEAK SHOT AT SNOW SHOWERS. HIGH PRESSURE IS ON TAP TO RETURN FOR THE WEEKEND. TEMPERATURE CONTINUES TO WARM THROUGH THE PERIOD WITH HIGHS EDGING INTO THE MID 30`S BY SUNDAY OVER SOUTHERN HALF OF THE CWA. && .MARINE... A SURFACE TROUGH SLOWLY DROPPING THROUGH LAKE HURON WILL MAINTAIN STRONG WESTERLY WINDS THROUGH THE REMAINDER OF THE AFTERNOON AND EVENING OVER SOUTHERN LAKE HURON...LAKE ST CLAIR...AND WESTERN LAKE ERIE. WINDS WILL BE STRONGEST OVER THE SOUTHERN THIRD OF LAKE HURON...WHERE GUSTS WILL PRIMARILY REMAIN AROUND 30 KNOTS...BUT A FEW GUSTS TO GALE FORCE ARE POSSIBLE. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR THE NEARSHORE WATERS OF LAKE HURON FROM OUTER SAGINAW BAY DOWN TO PORT HURON. THE REMAINDER OF THE NEARSHORE WATERS ARE ICE COVERED AND THEREFORE REMAIN WITHOUT A HEADLINE. WINDS WILL DECREASE EARLY TONIGHT AS THE SURFACE TROUGH DROPS SOUTHWARD. IN ADDITION...THE STRONG WINDS AND ARCTIC AIRMASS IN PLACE WILL CREATE FAVORABLE CONDITIONS FOR FREEZING SPRAY TO DEVELOP OVER LAKE HURON THROUGH TUESDAY...ESPECIALLY ACROSS THE OPEN WATERS. INTENSITY LOOKS TO ONLY REMAIN MODERATE HOWEVER. WINDS WILL REMAIN A LITTLE GUSTY OUT OF THE NORTHWEST ACROSS LAKE HURON TUESDAY BEFORE HIGH PRESSURE BUILDING INTO THE CENTRAL GREAT LAKES AND OHIO VALLEY BRINGS LIGHTER WIND CONDITIONS FROM LATE TUESDAY INTO WEDNESDAY. && .AVIATION...ISSUED 1243 PM EST MON JAN 18 2016 ARCTIC AIRMASS AND SURFACE WIND CONVERGENCE OVER SOUTHERN MICHIGAN WILL PROMOTE THE SPREAD OF LAKE EFFECT SNOW SHOWERS EASTWARD INTO THE DETROIT AREA TERMINALS. LATEST SATELLITE AND RADAR FAVORED SHOWERS OCCURRING ANYTIME AFTER 18Z...WITH POTENTIAL FOR OCCASIONAL SHOWERS TO AFFECT TERMINALS FROM PTK SOUTH THROUGH THIS EVENINGS. CEILINGS ARE EXPECTED TO PREVAIL AT VFR ACROSS SOUTHEAST MICHIGAN THIS AFTERNOON AND EVENING...WITH OCCASIONAL DROPS TO MVFR IN LAKE EFFECT SHOWERS. CONFIDENCE IN PREVAILING CEILINGS AT 3500 FEET IS NOT HIGH HOWEVER...AS THERE IS SOME UNCERTAINTY WITH HOW FAR EASTWARD FROM THE LAKE A 2500 FT CEILING OVER THE WEST SIDE OF THE STATE WILL PENETRATE. TIGHT SURFACE PRESSURE GRADIENT WILL MAINTAIN GUSTY WEST WINDS...WITH GUSTS PEAKING AROUND 25 KNOTS THIS AFTERNOON. HIGH PRESSURE SLOWLY BUILDING INTO THE WESTERN GREAT LAKES WILL DECREASE POTENTIAL FOR LAKE EFFECT SHOWERS TONIGHT...THEN BRING DRY VFR CONDITIONS TOMORROW AS IT SETTLES IN OVER THE OHIO VALLEY AND CENTRAL GREAT LAKES. FOR DTW...TIGHT SURFACE PRESSURE GRADIENT WILL MAINTAIN STRONG WEST WIND GUSTS (TO 25 KNOTS) THROUGH EARLY EVENING...WITH DIRECTION AT 250-260 KEEPING WINDS SHY OF CROSSWIND THRESHOLDS. SOME UNCERTAINTY WITH CEILING HEIGHTS TODAY (NOTE ABOVE)...BUT DO EXPECT TO SEE SOME DROPS TO MVFR IN OCCASIONAL LAKE EFFECT SNOW SHOWERS THAT WILL AFFECT THE TERMINAL AND AIRSPACE. SNOW ACCUMULATIONS WILL BE VERY LIGHT IF WE DO SEE ANY GOOD BURSTS. //DTW THRESHOLD PROBABILITIES... * HIGH FOR CEILING AOB 5000 FT THROUGH LATE TONIGHT. * HIGH FOR SNOW AS PRECIPITATION TYPE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LHZ421- 441>443. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ DISCUSSION...BT/DE MARINE.......HLO AVIATION.....HLO YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
325 PM EST MON JAN 18 2016 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 558 AM EST MON JAN 18 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST LOW-LEVEL CONVERGENCE SETS UP. WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20 RANGE THIS MORNING. TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING. AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE. ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING. TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW- LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND THEN BACK INTO ERN ALGER AND LUCE COUNTIES. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 324 PM EST MON JAN 18 2016 THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS SFC WINDS SHIFT TO A MORE S-SW DIRECTION. A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH 1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C. LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS 850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS. THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 110 PM EST MON JAN 18 2016 AT KIWD...WINDS VEERING MORE NW LATE THIS AFTERNOON WILL LOWER CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A RETURN TO VFR CONDITIONS TUE MORNING AS WINDS BACK TO THE SW. AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY INTO THIS EVENING. EXPECT SOME IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS DIMINISH. HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN PREVAILING IFR CONDITIONS THROUGH TUE MORNING. AT KSAW...EXPECT MAINLY CIGS NEAR 3K FT...BORDERLINE MVFR...THIS AFTERNOON BUT THEN EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 558 AM EST MON JAN 18 2016 A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20- 25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001>003- 084. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ014. LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ007. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ263>266. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...KF AVIATION...JLB MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
111 PM EST MON JAN 18 2016 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 558 AM EST MON JAN 18 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST LOW-LEVEL CONVERGENCE SETS UP. WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20 RANGE THIS MORNING. TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING. AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE. ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING. TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW- LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND THEN BACK INTO ERN ALGER AND LUCE COUNTIES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 AM EST MON JAN 18 2016 ...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND... UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE RECENT CHILL WITH THIS ARCTIC AIRMASS. STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2 INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT. AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT. APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT. SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH. ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT HAVE SOME SMALL CHANCE POPS. HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR 20S/LOWER 30S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 110 PM EST MON JAN 18 2016 AT KIWD...WINDS VEERING MORE NW LATE THIS AFTERNOON WILL LOWER CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A RETURN TO VFR CONDITIONS TUE MORNING AS WINDS BACK TO THE SW. AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY INTO THIS EVENING. EXPECT SOME IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS DIMINISH. HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN PREVAILING IFR CONDITIONS THROUGH TUE MORNING. AT KSAW...EXPECT MAINLY CIGS NEAR 3K FT...BORDERLINE MVFR...THIS AFTERNOON BUT THEN EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 558 AM EST MON JAN 18 2016 A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20- 25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002- 003-006-007-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001- 014-084. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ263>266. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...JLB MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
744 AM EST MON JAN 18 2016 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 558 AM EST MON JAN 18 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST LOW-LEVEL CONVERGENCE SETS UP. WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20 RANGE THIS MORNING. TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING. AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE. ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING. TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW- LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND THEN BACK INTO ERN ALGER AND LUCE COUNTIES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 AM EST MON JAN 18 2016 ...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND... UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE RECENT CHILL WITH THIS ARCTIC AIRMASS. STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2 INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT. AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT. APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT. SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH. ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT HAVE SOME SMALL CHANCE POPS. HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR 20S/LOWER 30S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 733 AM EST MON JAN 18 2016 AT KIWD...WINDS VEERING MORE NW LATER THIS AFTERNOON WILL LOWER CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY. EXPECT SOME IMPROVEMENT LATER THIS EVENING AS WINDS DIE DOWN ALTHOUGH CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN PREVAILING IFR CONDITIONS. AT KSAW...MVFR CONDITIONS WILL IMPROVE TO VFR BY AFTERNOON BUT THEN EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 558 AM EST MON JAN 18 2016 A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20- 25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002- 003-006-007-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001- 014-084. WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ263>267. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...VOSS MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
558 AM EST MON JAN 18 2016 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 558 AM EST MON JAN 18 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST LOW-LEVEL CONVERGENCE SETS UP. WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20 RANGE THIS MORNING. TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING. AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE. ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING. TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW- LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND THEN BACK INTO ERN ALGER AND LUCE COUNTIES. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 AM EST MON JAN 18 2016 ...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND... UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE RECENT CHILL WITH THIS ARCTIC AIRMASS. STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2 INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT. AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT. APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT. SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH. ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT HAVE SOME SMALL CHANCE POPS. HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR 20S/LOWER 30S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 353 AM EST MON JAN 18 2016 AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT. EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION. AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST WITH NORTHWEST WINDS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 558 AM EST MON JAN 18 2016 A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20- 25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002- 003-006-007-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001- 014-084. WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ263>267. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...07 MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 AM EST MON JAN 18 2016 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 408 PM EST SUN JAN 17 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW JUST TO THE EAST OF LAKE SUPERIOR. AT THE SFC...NW LOW LEVEL FLOW PREVAILED BTWN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN ONTARIO. RADAR AND VIS LOOP SHOWED MAINLY MULTI-BAND LES WITH FEW DOMINANT OR COHERENT BANDSAS THE LES INTENSITY HAS DIMINISHED SLIGHTLY WITH THE VERY DRY ARCTIC AIR UPSTREAM AND THE LAKES AGGREGATE TROUGH SHIFTING TO THE SOUTH OF UPPER MICHIGAN. INSTABILITY OVER THE LAKE REMAINED HIGH WITH 850/700 MB TEMPS AROUND -23C/-30C RESULTING IN LAKE INDUCED CAPES NEAR 1K J/KG AND EQUILIBRIUM HEIGHTS TO 14K FT. TONIGHT...EXPECT MODERATE TO OCCASIONALLY HEAVY LES TO CONTINUE FOR NW FLOW FAVORED LOCATIONS. THE HIGH RES MODELS SUGGEST THAT THE MOST LOW LEVEL CONV OVER THE WEST WILL FOCUS INTO ONTONAGON COUNTY THIS EVENING. OVER THE EAST...MORE DOMINANT BANDS COULD OVER A WIDER AREA FROM FROM ALGER COUNTY INTO LUCE COUNTY. LES INTENSITY SHOULD ALSO INCREASE WITH A SHRTWV OVER NRN ONTARIO ROTATING TO NEAR ERN LAKE SUPERIOR BY 12Z. HOWEVER...WINDS WILL ALSO BACK SLIGHTLY IN RESPONSE TO THE INCOMING SHRTWV. ALTHOUGH SNOWFALL AMOUNTS MAY NOT BE AS HEAVY AS LAST NIGHT...5 TO 9 INCH AMOUNTS WILL BE POSSIBLE OVER THE EAST. THE SHORTER FETCH AND SLIGHTLY LOWER INVERSION HEIGHTS OVER THE WEST SHOULD KEEP AMOUNTS IN THE 2 TO 5 INCH RANGE. ENOUGH OF THE CONVECTIVE LAYER WILL REACH INTO THE DGZ TO KEEP SLR VALUES AOA 25/1. THE VERY COLD AIR MOVING INTO INTERIOR LOCATIONS WILL DROP WIND CHILLS INTO THE -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS TONIGHT WHERE A WIND CHILL ADVY REMAINS IN EFFECT. EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20 RANGE. MONDAY...AS THE SHRTWV MOVES IN WITH THE STRONGER FORCING SHIFTING TO THE SOUTH...WINDS WILL GRADUALY VEER. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY LES...AGAIN HEAVIEST OVER THE EAST WITH SLIGHTLY HIGHER INVERSION HEIGHTS AND LONGER FETCH LENGTHS. WARNINGS AND ADVISORIES WILL REMAIN IN EFFECT THROUGH THE DAY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 AM EST MON JAN 18 2016 ...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND... UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE RECENT CHILL WITH THIS ARCTIC AIRMASS. STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2 INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT. AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT. APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT. SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH. ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT HAVE SOME SMALL CHANCE POPS. HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR 20S/LOWER 30S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 353 AM EST MON JAN 18 2016 AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT. EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION. AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST WITH NORTHWEST WINDS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 623 PM EST SUN JAN 17 2016 A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR INTO EARLY TUESDAY...KEEPING WIND GUSTS BETWEEN 25-30KTS WITH HIGHER GALE FORCE GUSTS TO 35 KNOTS POSSIBLE OVER EASTERN LAKE SUPERIOR LATE THIS AFTERNOON INTO TONIGHT. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED TODAY INTO MONDAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF NEXT WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002- 003-006-007-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001- 014-084. WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ263>267. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
354 AM EST MON JAN 18 2016 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 408 PM EST SUN JAN 17 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW JUST TO THE EAST OF LAKE SUPERIOR. AT THE SFC...NW LOW LEVEL FLOW PREVAILED BTWN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN ONTARIO. RADAR AND VIS LOOP SHOWED MAINLY MULTI-BAND LES WITH FEW DOMINANT OR COHERENT BANDSAS THE LES INTENSITY HAS DIMINISHED SLIGHTLY WITH THE VERY DRY ARCTIC AIR UPSTREAM AND THE LAKES AGGREGATE TROUGH SHIFTING TO THE SOUTH OF UPPER MICHIGAN. INSTABILITIY OVER THE LAKE REMAINED HIGH WITH 850/700 MB TEMPS AROUND -23C/-30C RESULTING IN LAKE INDUCED CAPES NEAR 1K J/KG AND EQUILLIBRIUM HEIGHTS TO 14K FT. TONIGHT...EXPECT MODERATE TO OCASSIONALLY HEAV LES TO CONTINUE FOR NW FLOW FAVORED LOCATIONS. THE HIGH RES MODELS SUGGEST THAT THE MOST FAVORALBE LOW LEVEL CONV OVER THE WEST WILL FOCUS INTO ONTONAGAON COUNTY THIS EVENING. OVER THE EAST...MORE DOMINANT BANDS COULD OVER A WIDER AREA FROM FROM ALGER COUNTY INTO LUCE COUNTY. LES INTENSITY SHOULD ALSO INCREASE WITH A SHRTWV OVER NRN ONTARIO ROTATING TO NEAR ERN LAKE SUPERIOR BY 12Z. HOWEVER...WINDS WILL ALSO BACK SLIGHTLY IN RESPONSE TO THE INCOMING SHRTWV. ALTHOUGH SNOWFALL AMOUNTS MAY NOT BE AS HEAVY AS LAST NIGHT...5 TO 9 INCH AMOUNTS WILL BE POSSIBLE OVER THE EAST. THE SHORTER FETCH AND SLIGHTLY LOWER INVERSION HEIGHTS OVER THE WEST SHOULD KEEP AMOUNTS IN THE 2 TO 5 INCH RANGE. ENOUGH OF THE CONVECTIVE LAYER WILL REACH INTO THE DGZ TO KEEP SLR VALUES AOA 25/1. THE VERY COLD AIR MOVING INTO INTERIOR LOCATIONS WILL DROP WIND CHILLS INTO THE -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS TONIGHT WHERE A WIND CHILL ADVY REMAINS IN EFFECT. EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20 RANGE. MONDAY...AS THE SHRTWV MOVES IN WITH THE STRONGER FORCING SHIFTING TO THE SOUTH...WINDS WILL GRADUALY VEER. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY LES...AGAIN HEAVIEST OVER THE EAST WITH SLIGHTLY HIGHER INVERSION HEIGHTS AND LONGER FETCH LENGTHS. WARNINGS AND ADVISORIES WILL REMAIN IN EFFECT THROUGH THE DAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 623 PM EST SUN JAN 17 2016 LES WILL DIMINISH MON NIGHT AND TUE AS 850MB TEMPS INCREASE FROM AROUND -22C AT 00Z TUE TO AROUND -12C BY 18Z TUE WHILE UPPER AND SFC RIDGING MOVES IN. STILL HAVE TO RESOLVE SOME MESOSCALE FEATURES THAT MAY LEAD TO BANDS OF MODERATE TO HEAVY SNOW INTO EARLY TUE MORNING...BUT THE COVERAGE OF HEAVIER SNOW POTENTIAL WILL REDUCE INTO THE MORNING...LOOKS LIKE IT WILL BE CONFINED TO ALGER AND NRN SCHOOLCRAFT COUNTIES. BY THE END OF THE DAY TUE WINDS MAY SWITCH OUT OF THE W-SW BEHIND THE RIDGE AND AHEAD OF A SHORTWAVE. EXPECT ONLY VERY MINOR SNOWFALL BY THE END OF THE DAY. POSSIBILITY OF A FEW INCHES MON NIGHT INTO TUE (MAINLY BEFORE NOON TUE) OVER THE ERN NW WIND FAVORED ZONES AND JUST A COUPLE INCHES OVER THE NWRN AREAS. MODELS SHOW A SHORTWAVE MOVING THROUGH THE REGION TUE NIGHT INTO WED...BUT THE TREND IS FOR MODELS TO SHIFT THAT S...WHICH IS ALSO THE CONSENSUS. WINDS OVER THE LAKES LOOK DISORGANIZED AND 850MB TEMPS AROUND -14C...SO ANY LAKE EFFECT WILL BE INSIGNIFICANT. MAY SEE ANOTHER WEAK SHORTWAVE MOVE THROUGH THE AREA WED NIGHT OR THU...BUT MODELS SHOW LITTLE TO NO QPF WITH THAT. SHOULD SEE LAKE ENHANCEMENT...POSSIBLE OVER THE KEWEENAW AND FAR NE DEPENDING ON WIND DIRECTIONS. NOT LOOKING AT SIGNIFICANT AMOUNTS WITH THIS SHORTWAVE EITHER. TREND AFTER THAT CONTINUES TO LOOK DRY AND WARMER. COULD SEE HIGHS AROUND 30 IN SOME SPOTS ON SAT...THEN A BIT COOLER ON SUN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 353 AM EST MON JAN 18 2016 AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT. EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION. AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST WITH NORTHWEST WINDS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 623 PM EST SUN JAN 17 2016 A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR INTO EARLY TUESDAY...KEEPING WIND GUSTS BETWEEN 25-30KTS WITH HIGHER GALE FORCE GUSTS TO 35 KNOTS POSSIBLE OVER EASTERN LAKE SUPERIOR LATE THIS AFTERNOON INTO TONIGHT. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED TODAY INTO MONDAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF NEXT WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002- 003-006-007-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001- 014-084. WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ263>267. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1157 PM EST SUN JAN 17 2016 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 408 PM EST SUN JAN 17 2016 WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW JUST TO THE EAST OF LAKE SUPERIOR. AT THE SFC...NW LOW LEVEL FLOW PREVAILED BTWN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN ONTARIO. RADAR AND VIS LOOP SHOWED MAINLY MULTI-BAND LES WITH FEW DOMINANT OR COHERENT BANDSAS THE LES INTENSITY HAS DIMINISHED SLIGHTLY WITH THE VERY DRY ARCTIC AIR UPSTREAM AND THE LAKES AGGREGATE TROUGH SHIFTING TO THE SOUTH OF UPPER MICHIGAN. INSTABILITIY OVER THE LAKE REMAINED HIGH WITH 850/700 MB TEMPS AROUND -23C/-30C RESULTING IN LAKE INDUCED CAPES NEAR 1K J/KG AND EQUILLIBRIUM HEIGHTS TO 14K FT. TONIGHT...EXPECT MODERATE TO OCASSIONALLY HEAV LES TO CONTINUE FOR NW FLOW FAVORED LOCATIONS. THE HIGH RES MODELS SUGGEST THAT THE MOST FAVORALBE LOW LEVEL CONV OVER THE WEST WILL FOCUS INTO ONTONAGAON COUNTY THIS EVENING. OVER THE EAST...MORE DOMINANT BANDS COULD OVER A WIDER AREA FROM FROM ALGER COUNTY INTO LUCE COUNTY. LES INTENSITY SHOULD ALSO INCREASE WITH A SHRTWV OVER NRN ONTARIO ROTATING TO NEAR ERN LAKE SUPERIOR BY 12Z. HOWEVER...WINDS WILL ALSO BACK SLIGHTLY IN RESPONSE TO THE INCOMING SHRTWV. ALTHOUGH SNOWFALL AMOUNTS MAY NOT BE AS HEAVY AS LAST NIGHT...5 TO 9 INCH AMOUNTS WILL BE POSSIBLE OVER THE EAST. THE SHORTER FETCH AND SLIGHTLY LOWER INVERSION HEIGHTS OVER THE WEST SHOULD KEEP AMOUNTS IN THE 2 TO 5 INCH RANGE. ENOUGH OF THE CONVECTIVE LAYER WILL REACH INTO THE DGZ TO KEEP SLR VALUES AOA 25/1. THE VERY COLD AIR MOVING INTO INTERIOR LOCATIONS WILL DROP WIND CHILLS INTO THE -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS TONIGHT WHERE A WIND CHILL ADVY REMAINS IN EFFECT. EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20 RANGE. MONDAY...AS THE SHRTWV MOVES IN WITH THE STRONGER FORCING SHIFTING TO THE SOUTH...WINDS WILL GRADUALY VEER. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY LES...AGAIN HEAVIEST OVER THE EAST WITH SLIGHTLY HIGHER INVERSION HEIGHTS AND LONGER FETCH LENGTHS. WARNINGS AND ADVISORIES WILL REMAIN IN EFFECT THROUGH THE DAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 623 PM EST SUN JAN 17 2016 LES WILL DIMINISH MON NIGHT AND TUE AS 850MB TEMPS INCREASE FROM AROUND -22C AT 00Z TUE TO AROUND -12C BY 18Z TUE WHILE UPPER AND SFC RIDGING MOVES IN. STILL HAVE TO RESOLVE SOME MESOSCALE FEATURES THAT MAY LEAD TO BANDS OF MODERATE TO HEAVY SNOW INTO EARLY TUE MORNING...BUT THE COVERAGE OF HEAVIER SNOW POTENTIAL WILL REDUCE INTO THE MORNING...LOOKS LIKE IT WILL BE CONFINED TO ALGER AND NRN SCHOOLCRAFT COUNTIES. BY THE END OF THE DAY TUE WINDS MAY SWITCH OUT OF THE W-SW BEHIND THE RIDGE AND AHEAD OF A SHORTWAVE. EXPECT ONLY VERY MINOR SNOWFALL BY THE END OF THE DAY. POSSIBILITY OF A FEW INCHES MON NIGHT INTO TUE (MAINLY BEFORE NOON TUE) OVER THE ERN NW WIND FAVORED ZONES AND JUST A COUPLE INCHES OVER THE NWRN AREAS. MODELS SHOW A SHORTWAVE MOVING THROUGH THE REGION TUE NIGHT INTO WED...BUT THE TREND IS FOR MODELS TO SHIFT THAT S...WHICH IS ALSO THE CONSENSUS. WINDS OVER THE LAKES LOOK DISORGANIZED AND 850MB TEMPS AROUND -14C...SO ANY LAKE EFFECT WILL BE INSIGNIFICANT. MAY SEE ANOTHER WEAK SHORTWAVE MOVE THROUGH THE AREA WED NIGHT OR THU...BUT MODELS SHOW LITTLE TO NO QPF WITH THAT. SHOULD SEE LAKE ENHANCEMENT...POSSIBLE OVER THE KEWEENAW AND FAR NE DEPENDING ON WIND DIRECTIONS. NOT LOOKING AT SIGNIFICANT AMOUNTS WITH THIS SHORTWAVE EITHER. TREND AFTER THAT CONTINUES TO LOOK DRY AND WARMER. COULD SEE HIGHS AROUND 30 IN SOME SPOTS ON SAT...THEN A BIT COOLER ON SUN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1157 PM EST SUN JAN 17 2016 AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT. EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION. AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST WITH NORTHWEST WINDS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 623 PM EST SUN JAN 17 2016 A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR INTO EARLY TUESDAY...KEEPING WIND GUSTS BETWEEN 25-30KTS WITH HIGHER GALE FORCE GUSTS TO 35 KNOTS POSSIBLE OVER EASTERN LAKE SUPERIOR LATE THIS AFTERNOON INTO TONIGHT. IN ADDITION...HEAVY FREEZING SPRAY IS EXPECTED TODAY INTO MONDAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH TOWARDS THE MIDDLE OF NEXT WEEK...AS HIGH PRESSURE MOVES OVER THE UPPER GREAT LAKES REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 PM EST MONDAY FOR MIZ002-003- 006-007-085. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST MONDAY FOR MIZ001-014- 084. WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR MIZ009-010. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST MONDAY FOR LSZ263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
908 PM CST TUE JAN 19 2016 .SYNOPSIS... ISSUED AT 325 PM CST TUE JAN 19 2016 H5 ANALYSIS THIS MORNING HAD A SHORTWAVE TROUGH EXTENDING FROM THE DAKOTAS INTO WESTERN NEBRASKA AND SRN COLORADO. UPSTREAM OF THE TROUGH...A LOW AMPLITUDE RIDGE EXTENDED FROM SWRN UTAH...NWD INTO SRN ALBERTA. WEST OF THE RIDGE...A SHORTWAVE TROUGH WAS PRESENT OFF THE COAST WASHINGTON STATE...OREGON AND NORTHERN CALIFORNIA. CURRENT WV IMAGERY...HAS THE SHORTWAVE EXTENDING FROM EASTERN SOUTH DAKOTA...INTO SOUTH CENTRAL NEBRASKA. FURTHER WEST...A BROAD PLUME OF PACIFIC MOISTURE WAS NOTED AND EXTENDED FROM CALIFORNIA...EWD INTO THE INTER MOUNTAIN WEST. A SECONDARY FEED OF MOISTURE EXTENDED FROM BAJA CALIFORNIA INTO TEXAS AND THE OZARKS. AT THE SURFACE...LIGHT SNOW IN ASSOCIATION WITH THE SHORTWAVE TROUGH...HAD EXITED THE FORECAST AREA BY LATE MORNING. SNOW AMOUNTS WERE ON THE ORDER OF 1 TO 2 INCHES ACROSS THE EASTERN HALF OF THE FORECAST AREA...WITH SOME LOCALLY HEAVIER AMOUNTS UP TO 3 INCHES IN CUSTER COUNTY. SEE OMAPNSLBF FOR DETAILS. SKIES WERE GENERALLY CLOUDY THIS AFTERNOON WITH THE EXCEPTION OF LOCATIONS ALONG AND WEST OF HIGHWAY 61 FROM MERRIMAN TO IMPERIAL. TEMPERATURES THIS AFTERNOON WERE GENERALLY IN THE 20S TO LOWER 30S. && .UPDATE... ISSUED AT 908 PM CST TUE JAN 19 2016 BINGO...DENSE FOG HAS FROMED ACROSS NRN NEB. THE RAP MODEL SHOWS THIS FOG MOVING EAST OVERNIGHT AND LASTING 3 TO 6 HOURS. IT IS POSSIBLE IT COULD FORM FARTHER SOUTH ACCORDING TO THIS MODEL BUT THAT REMAINS UNCERTAIN AT THIS TIME. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 325 PM CST TUE JAN 19 2016 CLEARING CONTINUES TO SPREAD FROM WEST TO EAST ACROSS THE AREA THIS EVENING. HOWEVER THE DRY AIR ALOFT AND GOOD RADIATIONAL COOLING WILL QUICKLY COOL THE SFC TO THE DEW POINT. BOTH THE SHREF AND NAM ARE SUGGESTING SOME FOG TO DEVELOP...AND WITH THE MELTING OF SOME OF THE LIGHT SNOW FROM THIS MORNING ADDING TO THE BL MOISTURE AND NEAR CALM WINDS...GROWING CONFIDENCE THIS COULD DEVELOP. UNSURE ON HOW DENSE IT WILL GET SO NO HEADLINE BUT WILL NEED TO MONITOR THIS CLOSELY. LOWS WILL BE MILD FOR MID JANUARY IN THE TEENS TO AROUND 20. TOMORROW THE FOG WILL SLOWLY ERODE AS THE NEXT WAVE EJECTS ONTO THE PLAINS. MOISTURE IS ON THE INCREASE...HOWEVER A DRY MID LEVEL WILL HAVE TO BE OVERCOME BEFORE ANYTHING REACHES THE GROUND...THUS EXPECT THE DAYTIME TO BE DRY. WEAK RIDGING AHEAD OF THE WAVE WILL PUSH SOME WARM AIR BRIEFLY INTO THE REGION WHICH SHOULD HELP PUSH EARLY HIGHS INTO THE MID 30S TO LOWER 40S...WARMEST WERE LITTLE TO NO SNOW PACK. IF CLOUDS THICKEN QUICKLY...HIGHS COULD BE TO OPTIMISTIC. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 325 PM CST TUE JAN 19 2016 MID RANGE...WEDNESDAY NIGHT THROUGH FRIDAY...THE MAIN FORECAST CHALLENGE IN THE MID RANGE IS SNOWFALL POTENTIAL WITH A SHORTWAVE SYSTEM PROGGED TO CROSS THE CENTRAL AND SRN PLAINS WEDS NIGHT INTO THURSDAY. BEGINNING LATE WEDNESDAY AFTERNOON...WITH THE APPROACH OF AN UPPER LEVEL JET STREAK...A SHORTWAVE TROUGH...WILL DEEPEN AS IT TRACKS FROM WYOMING INTO KANSAS. LIFT WILL BEGIN TO INCREASE OVERNIGHT WEDNESDAY NIGHT...NORTH OF THE SHORTWAVE...WHICH CLOSES OFF AT BOTH THE H7 AND H5 LEVELS AFTER 06Z THURSDAY. CROSS SECTIONS TAKEN ACROSS THE EASTERN CWA INDICATE PLENTY OF DENDRITIC ZONE MOISTURE...ALONG WITH A 12 HR PERIOD (06Z-18Z THURSDAY) OF FAVORABLE LIFT. THIS AREA OF LIFT IS COLLOCATED WITH AN INVERTED SURFACE TROUGH OF LOW PRESSURE WHICH IS PRESENT ACROSS THE EASTERN CWA...OR MAINLY ALONG THE HIGHWAY 183 CORRIDOR FROM ANSLEY TO SPRINGVIEW. SREF QPF/S AS WELL AS THE OPERATIONAL GFS AND NAM SOLNS INDICATE 10 TO 20 HUNDREDTHS OF AN INCH ALONG THIS CORRIDOR...WHICH BASED ON COBB RATIOS OF 12 TO 1...YIELDS 1 TO 2 INCHES OF SNOW IN THE EASTERN HALF OF THE CWA. BASED ON THE CROSS SECTIONS...THIS WILL BE A FAIRLY LONG (12 HRS)...LIGHT INTENSITY EVENT. ATTM FEEL FAIRLY CONFIDENT IN QPF/S AND ACCUMS...HOWEVER...LAYER PWATS IN THE NAM SOLN ARE RUNNING A QUARTER TO BRIEFLY A HALF AN INCH DURING THE PERIOD AND THIS IS CONCERNING. IF THIS VERIFIES...WE COULD BE LOOKING AT MORE SNOW ACCUMS THAN CURRENT THINKING. WILL CONTINUE TO MONITOR THIS WITH THE NEXT COUPLE OF FCST CYCLES. PROGRESSING INTO THURSDAY AFTERNOON...THE UPPER LEVEL LOW WILL TRACK SOUTHEAST INTO THE OZARKS...AS A RIDGE BEGINS TO BUILD INTO THE INTER MOUNTAIN WEST. LIFT WILL BEGIN TO WEAKEN QUICKLY BY THURSDAY AFTERNOON IN THE EAST...WHILE HIGH PRESSURE BUILDS SOUTH FROM THE EASTERN DAKOTAS. SUBSIDENCE AND DRIER AIR...WILL BRING THE THREAT FOR SNOW TO AN END DURING THE AFTERNOON HOURS. ON THURSDAY NIGHT...HIGH PRESSURE WILL BUILD SOUTH INTO EASTERN NEBRASKA. LOW TEMPERATURES WERE TRENDED DOWNWARD IN THE EAST GIVEN ITS PROXIMITY TO THE TRACK OF THE HIGH WITH GUIDANCE UNDERCUT 2 TO 5 DEGREES. HIGH PRESSURE WILL TRANSITION EAST INTO MINNESOTA AND NORTHERN IOWA BY FRIDAY AFTERNOON. WARMER AIR WILL BEGIN TO PUSH INTO WESTERN NEBRASKA BY AFTERNOON...WITH H85 TEMPS REACHING ABOVE 0C WEST OF HIGHWAY 61. WINDS...ESPECIALLY EAST OF HIGHWAY 61 WILL BE LIGHT...SO NOT MUCH MIXING WILL TAKE PLACE. THIS WILL RESULT IN SUB FREEZING HIGHS GENERALLY EAST OF HIGHWAY 83...WHILE LOCATIONS WEST OF THIS ROUTE MAY REACH THE MID 30S TO LOWER 40S IN THE EASTERN PANHANDLE. LONG RANGE...FRIDAY NIGHT THROUGH TUESDAY...BEGINNING FRIDAY NIGHT...RIDGING WILL BUILD EAST OF THE ROCKIES ONTO THE CENTRAL PLAINS. MUCH WARMER H85 AIR WILL PUSH EAST WITH H85 TEMPS SAT AFTERNOON OF 4 TO 8C. INHERITED FCST OF 40S TO LOWER 50S SATURDAY ARE ON TRACK. A PACIFIC COOL FRONT WILL PUSH INTO THE FORECAST AREA SUNDAY AFTERNOON. HIGHS WILL FALL BACK TO MORE SEASONAL LEVELS SUNDAY...MONDAY AND TUESDAY. WITH THE FRONTAL PASSAGE...THERE WILL BE A SMALL THREAT FOR RAIN OR SNOW SHOWERS SUNDAY...FOLLOWED BY A SLIGHT CHANCE FOR SNOW ON SUNDAY NIGHT. BEYOND TUESDAY...THE LATEST ECMWF AND GFS SOLNS DEVELOP A ZONAL FLOW PATTERN NEXT WEEK WITH ARCTIC AIR WELL NORTH OF THE CWA. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 534 PM CST TUE JAN 19 2016 THE GENERAL CONSENSUS OF THE RAP...HRRR AND NAM MODELS SUGGESTS A BANK OF FOG WILL FORM ON THE WRN FLANK OF THE STRATUS CURRENTLY IN PLACE ACROSS NCNTL NEB. THE FOG LOCATION COULD BE SOMEWHAT WEST OF HIGHWAY 83. WE WILL HAVE TO WAIT FOR IT TO FORM TO GET A FIX ON THE LOCATION. OTHERWISE...A LOW LEVEL JET FORMS TONIGHT WEST OF THE FOG BANK ALONG HIGHWAY 61 ANGLED TOWARD VALENTINE. THIS SHOULD SCOUR MOISTURE FROM THE SANDHILLS AND LEAVE A POOL OF TRAPPED MOISTURE OVER KLBF WEDNESDAY. GIVEN THAT...IFR/MVFR CIGS COULD BE LOCKED IN ALL DAY OVER KLBF. && .LBF WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 9 AM CST /8 AM MST/ WEDNESDAY FOR NEZ005>010. && $$ UPDATE...CDC SYNOPSIS...BUTTLER SHORT TERM...MASEK LONG TERM...BUTTLER AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
533 PM CST TUE JAN 19 2016 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 336 PM CST TUE JAN 19 2016 MAIN CONCERN IS FOG POTENTIAL TONIGHT. GENERAL SYNOPTIC PATTERN IS QUITE PROGRESSIVE AS WE TRANSITION TO A HIGHER AMPLITUDE SCENARIO. TONIGHT...THE CONCERN GOES TO FOG POTENTIAL TONIGHT AS WIND WILL BE LIGHT FROM THE SOUTH. THE HRRR IS HITTING THE FOG POTENTIAL A LITTLE HARD CENTRAL AND WEST. THE SREF IS ALSO HITTING FOG A LITTLE HARD EVERYWHERE ACROSS THE CWA...ESPECIALLY WEST. I WENT WITH STRONG WORDING IN THE FORECAST TO AREAS RATHER THAN PATCHY AND EXTENDED THE FOG MENTION FARTHER EAST THAN THE PREVIOUS FORECAST. WE MAY SEE A LITTLE SUN WEDNESDAY MORNING BEFORE IT CLOUDS BACK UP IN ADVANCE OF THE NEXT WAVE QUICKLY APPROACHING. WARM AIR ADVECTION SHOULD BOOST TEMPERATURES A GOOD 10 DEGREES WARMER ON WEDNESDAY COMPARED TO TODAY. NOT EXPECTING PRECIP UNTIL PERHAPS BETWEEN 21Z AND 00Z THURSDAY IN OUR FAR SOUTH...WHERE RAIN/SNOW COULD OCCUR...BUT THE BETTER CHANCES WILL LIKELY BE TOWARD WEDNESDAY NIGHT...IN THE LONG TERM FORECAST. SUPERBLEND TEMPERATURES LOOKED REASONABLE...WHICH LOWERED TEMPERATURES A BIT FOR WEDNESDAY HIGHS COMPARED TO THE PREVIOUS FORECAST. THIS SEEMS REASONABLE CONSIDERING LINGERING FOG POTENTIAL AND INCREASING SKY COVER BY AFTERNOON. BCONSRAW AND NAM12 SOLUTIONS INDICATE THAT IT MIGHT EVEN BE A BIT COOLER THAN THE MID 30S I HAVE ADVERTISED IN THE FORECAST....WITH COOLER TEMPERATURES EAST AND WARMER WEST. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 336 PM CST TUE JAN 19 2016 ALOFT: VERY LITTLE CHANGE IN THE PATTERN IS ENVISIONED FOR AT LEAST THE NEXT WEEK. A MEAN TROF WILL REMAIN OVER THE E PAC WITH THE MEAN RIDGE OVER WRN N AMERICA. THE FLOW WILL INITIALLY BE MODERATELY AMPLIFIED BUT WILL DEAMPLIFY TEMPORARILY AS A TROF MOWS DOWN THE RIDGE FRI-SAT AND EMERGES INTO THE PLAINS SUN-MON. NW FLOW WILL FOLLOW TUE. AT 00Z/THU A SHORTWAVE TROF WILL BE MOVING IN AND AMPLIFYING...WITH A MID-LVL CIRCULATION CLOSING OFF OVER NEB/KS BY 06Z. THIS LOW WILL DROP SSE THU WITH QUIETER WX TO FOLLOW. SURFACE: A WEAK COLD FRONT WILL MOVE THRU WED NIGHT. LEE CYCLOGENESIS WILL BE UNDERWAY WED EVE WITH THE SFC LOW FAR TO THE S OVER TX. CANADIAN HIGH PRES WILL GRADUALLY BUILD IN THU-FRI. RETURN FLOW DEVELOPS SAT AS A CLIPPER HEADS E ACROSS SRN CANADA. A NICE DOWNSLOPE-WARMED AIR MASS WILL OVERTAKE THE REGION...BUT SNOW ON THE GROUND WILL TEMPER THE WARM-UP. THE NEXT PAC COOL FRONT WILL BE MAKING ITS WAY THRU THE WRN USA AND WILL ARRIVE HERE LATE SUN. HIGH PRES WILL MOVE IN MON AND DROP INTO THE SRN PLAINS TUE. SOME DAILY DETAILS... WED NIGHT: SNOW WILL BE BLOSSOMING OVER N-CNTRL KS AND EXPANDING N INTO S-CNTRL NEB. THU: A SWATH OF SNOW WILL PROBABLY STILL ENCOMPASS MUCH OF THE FCST AREA THRU THE MORNING...RESULTING IN PERIODS OF SNOW. IT WILL DIMINISH AND END IN THE AFTERNOON. CURRENT EXPECTATION IS THAT MOST IF NOT ALL THE ACCUMULATING SNOW WILL FALL WED NIGHT. WHILE SNOW WILL CONT INTO THU THE LIFT WILL NOT BE ENOUGH TO RESULT IN MUCH ACCUM. SNOW RATIOS: THIS IS TOUGH BECAUSE THE MESOSCALE NATURE OF THIS SYSTEM WILL RESULT IN HIGHLY NON-UNIFORM LIFT. HIGHER UPWARD VERTICAL MOTION (UVM) WILL RESULT IN HIGHER RATIOS WITHIN THE BAND. GIVEN THAT THE BAND SHOULD BE TRANSIENT...KEPT RATIOS IN THE 10-12 RANGE. BASED ON NAM SOUNDINGS...UVM WILL BE FAIRLY GOOD BELOW THE DGZ FROM I-80 SOUTH. WITH TEMPS WARMER THAN -5C...THIS WILL RESULT IN SUBSTANTIAL RIMING AND RATIOS CLOSE TO 10:1...IE A WETTER SNOW. N OF I-80...IF THE NAM IS CORRECT UVM WILL BE WEAK RESULTING IN LESSER QUALITY/SMALLER FLAKES. THAT TOO SUPPORTS A LOWER RATIO OF 10 OR LESS. ACCUMS: THESE RATIOS OFFER 1-2" AND THAT IS THE OFFICIAL FCST AT THIS POINT...WITH 3-4" POSSIBLE IN A SMALLER AREA WHERE THE BAND IS MORE PERSISTENT. WE JUST DON`T KNOW WHERE THAT WILL OCCUR. SNOW ALGORITHMS FROM THE 06Z/12Z 20KM GFS AND 12Z/18Z NAM OFFER 2-4" ACROSS MUCH OF THE FCST AREA...WITH ISOLATED 6" AMTS POSSIBLE. THE EC CONTS TO BE ON THE HEAVY SIDE OF THE GUIDANCE DISTRIBUTION CONSISTENTLY DUMPING ABOUT .50" SOMEWHERE NEAR ROOKS/OSBORNE/ MITCHELL COUNTIES. THAT INCLUDES THE LAST 4 RUNS. HOWEVER...THE 12Z EC ENSEMBLE MEAN PROBABILITY FOR .50" IN 24 HRS 10% OR LESS. SO THAT CONSTRAINS ME FROM GETTING OVERLY EXCITED. WINDS WILL NOT BE A FACTOR WITH THIS EVENT. FRI: DECREASING CLOUDS AS SUBSIDENT NW FLOW MOVES IN. HIGH TEMPS PROBABLY COLDER THAN NORMAL. SAT: TEMPS AT LEAST NORMAL IF NOT ABOVE. SNOW ON THE GROUND IS A HUGE MITIGATING FACTOR. OTHERWISE...WIDESPREAD HIGHS IN THE 40S AND 50S WOULD BE ON THE TABLE. SUN-MON: INCREASING CLOUDS. COOLER. POSSIBLY A TOUGH OF LIGHT PRECIP AS THE FRONT/TROF MOVE IN. && .AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 533 PM CST TUE JAN 19 2016 THE MAIN AVIATION FORECAST CONCERN IS THE DEVELOPMENT OF FOG OVERNIGHT. WINDS WILL BE LIGHT THROUGHOUT THE NIGHT...ALLOWING FOG TO DEVELOP IN THE MOIST...SNOW COVERED BOUNDARY LAYER. HAVE TRENDED DOWNWARD FROM THE PREVIOUS FORECAST WITH MVFR CONDITIONS CONTINUED OVERNIGHT TOWARDS MORNING. THE HRRR IS THE MOST PESSIMISTIC REGARDING CEILINGS AND VISIBILITIES...OTHER GUIDANCE IS NOT QUITE THAT RESTRICTIVE AS FAR EAST AS KGRI. IF THE HRRR IS ACCURATE IFR TO LIFR CONDITIONS COULD BE POSSIBLE TOWARDS MORNING. WILL BE WATCHING FOR LATER FORECASTS AND AMENDING IF NEEDED FOR LOWER VISIBILITIES/CEILINGS WITH FOG DEVELOPMENT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...HALBLAUB AVIATION...BILLINGS WRIGHT
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
945 AM PST MON JAN 18 2016 .SYNOPSIS...A PROGRESSIVE PACIFIC WEATHER PATTERN WILL DIRECT STORMS MAINLY ACROSS NORTHERN CALIFORNIA AND NEVADA THIS WEEK. HOWEVER...CONSIDERABLE CLOUDINESS AND EVEN A CHANCE FOR SOME LIGHT PRECIPITATION WILL MANAGE TO BRUSH THE SOUTHERN GREAT BASIN AND PARTS OF THE MOJAVE DESERT MONDAY AND TUESDAY. && .UPDATE...JUST SENT OUT AN UPDATE TO MAKE SOME TWEAKS TO CLOUDS AND POPS FOR TODAY. MAINLY ADJUSTED CLOUD COVER DOWNWARD ACROSS THE WESTERN MOJAVE DESERT AND DEATH VALLEY AREA THIS MORNING WHERE A DRY PUNCH IS CLEARLY PUSHING IN AS NOTED ON SATELLITE IMAGERY. THIS WILL SPREAD EAST LATER THIS MORNING BREAKING UP THE THICKER CLOUD COVER ACROSS SOUTHERN NEVADA AS WELL. MADE ONLY MINOR ADJUSTMENTS TO POPS BUT DO THINK THE SOUTHERN EXTENT OF PRECIP CHANCES ACROSS THE DESERTS INCLUDING LAS VEGAS IS LOOKING QUITE LOW. MAINTAINED SLIGHT CHANCE FOR LAS VEGAS AS THE REMAINS OF THE PACIFIC FRONT MOVE THROUGH BUT ADJUSTED TO SPRINKLES WORDING AND WOULDNT BE SURPRISED TO SEE NOTHING MATERIALIZE AT ALL. MEANWHILE...CAMS SHOWING SHOWERS BREAKING OUT ACROSS THE NORTHERN OWENS VALLEY NEAR BISHOP SO THINGS ARE ON TRACK UP THERE. STRONGER DRY PUNCH PUSHING IN MAY ALSO TRANSLATE TO BREEZY SOUTHWEST WINDS LATER THIS AFTERNOON FOR MANY OF THE LOWER DESERT CITIES. -OUTLER- && .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. CONSIDERABLE MID AND HIGH-LEVEL MOISTURE HAS OVERSPREAD THE REGION THIS MORNING AS A WAVE PUSHES INTO THE CENTRAL AND SOUTHERN CALIFORNIA COAST. SOME ENHANCED SOUTHWEST WINDS ARE EXPECTED TO DEVELOP THIS MORNING ACROSS THE WESTERN MOJAVE DESERT...MAINLY NEAR FORT IRWIN AND BARSTOW. WINDS ARE EXPECTED TO MAINLY REMAIN BELOW ADVISORY CRITERIA...WITH A STRAY GUST IN EXCESS OF 40 MPH NEAR FORT IRWIN. THIS SYSTEM WILL PUSH A NARROW BAND OF ENHANCED LOW TO MID- LEVEL MOISTURE ACROSS THE REGION TODAY...WHICH CLOUD RESULT IN A FEW ISOLATED TO SCATTERED SHOWERS WHEN COMBINED WITH NEARBY WEAK DYNAMICS. THE BEST CHANCES FOR THESE SHOWERS WILL BE ACROSS THE SIERRA AND SOUTHERN GREAT BASIN...BUT THE LATEST HRRR RUNS HAVE SHOWN SOME ACTIVITY A BIT FURTHER SOUTH AND I CANNOT COMPLETELY RULE OUT A FEW STRAY SHOWERS ALONG THE I-15 CORRIDOR. POPS WERE EXPANDED AS A RESULT. ANY SHOWER ACTIVITY SHOULD TAPER OFF THIS EVENING WITH QUIET CONDITIONS EXPECTED OVERNIGHT. ANOTHER WAVE WILL PUSH ACROSS NORTHERN CALIFORNIA AND NEVADA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT...WHICH WILL RESULT IN ANOTHER THIN BAND OF ENHANCED MOISTURE DIRECTED AT THE REGION. DYNAMICS ASSOCIATED WITH THIS SYSTEM ARE QUITE A BIT FURTHER NORTH...BUT THE MOISTURE LEVELS ARE HIGHER. THEREFORE...SIMILAR PRECIPITATION CHANCES CAN BE EXPECTED WITH THIS SECOND SYSTEM COMPARED TO TODAY. PRECIPITATION AMOUNTS WITH BOTH SYSTEMS SHOULD BE LIGHT...WITH THE SIERRA SEEING THE HIGHEST ACCUMULATIONS. IN THE SIERRA...0.2-0.4 INCHES OF LIQUID...OR 3-6 INCHES OF SNOW ABOVE 7000 FEET IS EXPECTED WITH EACH SYSTEM). ELSEWHERE...AMOUNTS (IF ANY) WOULD BE A TRACE TO 0.1 INCH OF LIQUID. DRIER CONDITIONS WILL RETURN TO THE REGION WEDNESDAY AS A RIDGE AMPLIFIES OVER THE WESTERN CONUS. TEMPERATURES ARE EXPECTED TO RUN NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE SHORT TERM. .LONG TERM...THURSDAY THROUGH MONDAY. NOT MUCH CHANGE TO THE LONG TERM FROM THIS TIME YESTERDAY. AMPLIFIED BUT PROGRESSIVE RIDGING WILL BE IN PLACE THURSDAY IN ADVANCE OF THE NEXT SYSTEM APPROACHING THE WEST COAST BY 00Z SATURDAY. A FEW TIMING DISCREPANCIES REMAIN WITH THIS NEXT SYSTEM LARGELY OWING TO THE DIFFERENCES IN THE AMPLITUDE OF THE RIDGING IN THE INTERIOR WEST WITH THE ECMWF REMAINING SOMEWHAT STRONGER AND LESS PROGRESSIVE WITH THE EARLY WEEKEND SYSTEM AND THE 00Z CMC SLOWER STILL. NEVERTHELESS, MODELS CONTINUE TO SUGGEST NOT MUCH PRECIP EXCEPT FOR FAR NORTHERN PORTIONS OF THE CWA. TIMING OF ONSET OF PRECIP REMAINS LOW CONFIDENCE WITH ANYWHERE BETWEEN 12Z-18Z FRIDAY (GFS/ECMWF) AND 06Z SATURDAY (CMC) DEPICTED. IF THE ONSET OF PRECIP IS FASTER...ABOUT A 24-HOUR PERIOD OF SNOW IS LIKELY NEAR THE SIERRA CREST...WHEREAS THE CMC PROVIDES A MUCH BRIEFER WINDOW (MORE LIKE 12 HOURS). NOT VERY CONFIDENT DISCUSSING PRECIP TOTALS GIVEN THESE DISCREPANCIES...BUT THE MORE AGGRESSIVE SOLUTIONS ARE NOT GENERATING IMPRESSIVE TOTALS DURING THIS TIME. PRECIP FOR THE SOUTHERN GREAT BASIN IS MORE UNCERTAIN...WITH MODEL SOLUTIONS CONTINUING TO DIVERGE DURING THIS TIME. THE CMC PRODUCES LITTLE IF ANY PRECIP FOR THIS AREA AS THE FIRST OF TWO VORT MAXES PROGRESSES RAPIDLY EASTWARD INTO ID/UT BY 18Z SATURDAY, STAYING TOO FAR NORTH TO GENERATE SUFFICIENT LIFT FOR PRECIP IN OUR AREA. THE GFS PROVIDES FAIRLY DECENT AGREEMENT WITH THIS SCENARIO...THOUGH IT IS SLIGHTLY FARTHER SOUTH...CLIPPING AT LEAST THE FAR NORTHERN CWA. THE 00Z ECMWF IS DEEPER WITH THIS TROUGH...ENABLING SCATTERED PRECIP TO BREAK OUT INTO NORTHERN CLARK AND MOHAVE COUNTIES. THE EURO ALSO KEEPS THIS PRECIP AROUND LONGER GIVEN THE SLOWER PROGRESSION OF THE TROUGH...THROUGH 06Z SUNDAY. FOR NOW...BROAD-BRUSHED LOW POPS FOR THE SOUTHERN GREAT BASIN ON SATURDAY. IF PRECIP DOES OCCUR...AMOUNTS SHOULD BE LIGHT IN THIS AREA. MODELS DIVERGE FURTHER INTO THE DAY SUNDAY WITH THE 00Z ECMWF DEVELOPING AN UPSTREAM VORT MAX RAPIDLY PROGRESSING FROM NORTHWEST TO SOUTHEAST THROUGH THE AREA BY 00Z MONDAY. THE GFS DEVELOPS A SIMILAR VORT MAX BUT MUCH FARTHER SOUTH (CLIPPING THE FAR SOUTHERN PARTS OF THE CWA). MEANWHILE, THE CMC DEVELOPS THIS SYSTEM TO THE NORTHEAST OF THE AREA. GOOD NEWS IS ALL THREE PRODUCE VERY LIGHT PRECIP AT MOST WITH THIS VORT MAX. AS SUCH...UNTIL MODELS CONVERGE...KEPT SILENT TO VERY SLIGHT CHANCE POPS IN FOR THE DAY SUNDAY. TEMPERATURES WILL BE SLIGHTLY ABOVE AVERAGE THURSDAY THROUGH SUNDAY...WITH THE WARMEST TEMPS ON FRIDAY AND THE COOLEST TEMPS ON SUNDAY FOLLOWING THE PASSAGE OF THE WEAK SYSTEMS MOVING THROUGH THIS WEEKEND. THEREAFTER, MODELS DEVELOP A HIGH-AMPLITUDE RIDGE ALONG THE WEST COAST AND DRY CONDITIONS FOR OUR AREA. THE CHARACTERISTICS OF THIS RIDGE VARY BASED ON MODEL OF CHOICE, BUT ALL SEEM TO AGREE THAT STRONG NORTHERLY FLOW DEVELOPS IN OUR AREA MONDAY, SUGGESTING THAT WINDS MAY BLOW RATHER STRONGLY IN THE COLORADO RIVER VALLEY. PLENTY OF TIME TO DETERMINE IF THIS COMES TO FRUITION. PERHAPS OF MORE IMPORTANCE, THE SOLUTIONS ARE TRENDING TOWARD A STRONGER SUBTROPICAL RIDGE IN THE EAST PACIFIC NEXT WEEK, WHICH DOES NOT BODE WELL FOR A MORE SOUTHERN STORM TRACK ANY TIME SOON. && .AVIATION...FOR MCCARRAN...MAINLY LIGHT WINDS THROUGH MID-DAY FOLLOWING TYPICAL DIURNAL TRENDS. CIGS WILL LOWER THROUGH THE DAY...DROPPING TO AROUND 8K FEET BY THIS EVENING. A STRAY SHOWER CANNOT BE COMPLETELY RULED OUT DURING THE AFTERNOON. THE WIND FORECAST BECOMES TRICKY THIS AFTERNOON AS THERE COULD BE A BATTLE BETWEEN EAST/NORTHEAST WINDS AND GUSTY SOUTHWEST WINDS IN THE VICINITY OF THE TERMINAL. WITH THE POTENTIAL FOR A SHOWER AND SIGNIFICANT CLOUD COVER...WITH ERR ON THE SIDE OF LIGHTER EAST/NORTHEAST WINDS FOR THE 12Z TAF. IN REALITY...WINDS COULD FAVOR EITHER DIRECTION BETWEEN ROUGHLY 19Z-01Z THIS AFTERNOON. QUIET WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY...WITH ANOTHER VERY SLIGHT CHANCE OF SHOWERS TUESDAY EVENING. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...INCREASING SOUTHWEST WINDS EXPECTED ACROSS THE WESTERN MOJAVE DESERT THIS MORNING (MAINLY SOUTH OF A KNID-KDRA-KSGU LINE). TO THE NORTH...LIGHTER WINDS ARE EXPECTED TO FAVOR TYPICAL DIURNAL TRENDS IN VALLEY LOCATIONS. IT`S UNCLEAR WHETHER THE SOUTHWEST WINDS WILL MAKE IT INTO THE LAS VEGAS VALLEY...WITH KHND BEING THE MOST LIKELY LOCATION IF THEY DO. CIGS ARE EXPECTED TO DROP TO 5-8K FEET AS A WEAK SYSTEM PASSES THROUGH THE REGION. THIS WILL ALSO BRING A SLIGHT CHANCE OF SHOWERS TO THE REGION...MAINLY NORTH OF LAS VEGAS...HOWEVER A FEW STRAY SHOWERS TO THE SOUTH CANNOT BE RULED OUT. QUIET WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY MORNING...WITH ANOTHER SLIGHT CHANCE OF SHOWERS ACROSS THE REGION TUESDAY. && .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED. PLEASE REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ SHORT TERM/AVIATION...WOLCOTT LONG TERM.............SHAFER FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
300 AM PST MON JAN 18 2016 .SYNOPSIS...A PROGRESSIVE PACIFIC WEATHER PATTERN WILL DIRECT STORMS MAINLY ACROSS NORTHERN CALIFORNIA AND NEVADA THIS WEEK. HOWEVER...CONSIDERABLE CLOUDINESS AND EVEN A CHANCE FOR SOME LIGHT PRECIPITATION WILL MANAGE TO BRUSH THE SOUTHERN GREAT BASIN AND PARTS OF THE MOJAVE DESERT MONDAY AND TUESDAY. && .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. CONSIDERABLE MID AND HIGH-LEVEL MOISTURE HAS OVERSPREAD THE REGION THIS MORNING AS A WAVE PUSHES INTO THE CENTRAL AND SOUTHERN CALIFORNIA COAST. SOME ENHANCED SOUTHWEST WINDS ARE EXPECTED TO DEVELOP THIS MORNING ACROSS THE WESTERN MOJAVE DESERT...MAINLY NEAR FORT IRWIN AND BARSTOW. WINDS ARE EXPECTED TO MAINLY REMAIN BELOW ADVISORY CRITERIA...WITH A STRAY GUST IN EXCESS OF 40 MPH NEAR FORT IRWIN. THIS SYSTEM WILL PUSH A NARROW BAND OF ENHANCED LOW TO MID- LEVEL MOISTURE ACROSS THE REGION TODAY...WHICH CLOUD RESULT IN A FEW ISOLATED TO SCATTERED SHOWERS WHEN COMBINED WITH NEARBY WEAK DYNAMICS. THE BEST CHANCES FOR THESE SHOWERS WILL BE ACROSS THE SIERRA AND SOUTHERN GREAT BASIN...BUT THE LATEST HRRR RUNS HAVE SHOWN SOME ACTIVITY A BIT FURTHER SOUTH AND I CANNOT COMPLETELY RULE OUT A FEW STRAY SHOWERS ALONG THE I-15 CORRIDOR. POPS WERE EXPANDED AS A RESULT. ANY SHOWER ACTIVITY SHOULD TAPER OFF THIS EVENING WITH QUIET CONDITIONS EXPECTED OVERNIGHT. ANOTHER WAVE WILL PUSH ACROSS NORTHERN CALIFORNIA AND NEVADA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT...WHICH WILL RESULT IN ANOTHER THIN BAND OF ENHANCED MOISTURE DIRECTED AT THE REGION. DYNAMICS ASSOCIATED WITH THIS SYSTEM ARE QUITE A BIT FURTHER NORTH...BUT THE MOISTURE LEVELS ARE HIGHER. THEREFORE...SIMILAR PRECIPITATION CHANCES CAN BE EXPECTED WITH THIS SECOND SYSTEM COMPARED TO TODAY. PRECIPITATION AMOUNTS WITH BOTH SYSTEMS SHOULD BE LIGHT...WITH THE SIERRA SEEING THE HIGHEST ACCUMULATIONS. IN THE SIERRA...0.2-0.4 INCHES OF LIQUID...OR 3-6 INCHES OF SNOW ABOVE 7000 FEET IS EXPECTED WITH EACH SYSTEM). ELSEWHERE...AMOUNTS (IF ANY) WOULD BE A TRACE TO 0.1 INCH OF LIQUID. DRIER CONDITIONS WILL RETURN TO THE REGION WEDNESDAY AS A RIDGE AMPLIFIES OVER THE WESTERN CONUS. TEMPERATURES ARE EXPECTED TO RUN NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE SHORT TERM. .LONG TERM...THURSDAY THROUGH MONDAY. NOT MUCH CHANGE TO THE LONG TERM FROM THIS TIME YESTERDAY. AMPLIFIED BUT PROGRESSIVE RIDGING WILL BE IN PLACE THURSDAY IN ADVANCE OF THE NEXT SYSTEM APPROACHING THE WEST COAST BY 00Z SATURDAY. A FEW TIMING DISCREPANCIES REMAIN WITH THIS NEXT SYSTEM LARGELY OWING TO THE DIFFERENCES IN THE AMPLITUDE OF THE RIDGING IN THE INTERIOR WEST WITH THE ECMWF REMAINING SOMEWHAT STRONGER AND LESS PROGRESSIVE WITH THE EARLY WEEKEND SYSTEM AND THE 00Z CMC SLOWER STILL. NEVERTHELESS, MODELS CONTINUE TO SUGGEST NOT MUCH PRECIP EXCEPT FOR FAR NORTHERN PORTIONS OF THE CWA. TIMING OF ONSET OF PRECIP REMAINS LOW CONFIDENCE WITH ANYWHERE BETWEEN 12Z-18Z FRIDAY (GFS/ECMWF) AND 06Z SATURDAY (CMC) DEPICTED. IF THE ONSET OF PRECIP IS FASTER...ABOUT A 24-HOUR PERIOD OF SNOW IS LIKELY NEAR THE SIERRA CREST...WHEREAS THE CMC PROVIDES A MUCH BRIEFER WINDOW (MORE LIKE 12 HOURS). NOT VERY CONFIDENT DISCUSSING PRECIP TOTALS GIVEN THESE DISCREPANCIES...BUT THE MORE AGGRESSIVE SOLUTIONS ARE NOT GENERATING IMPRESSIVE TOTALS DURING THIS TIME. PRECIP FOR THE SOUTHERN GREAT BASIN IS MORE UNCERTAIN...WITH MODEL SOLUTIONS CONTINUING TO DIVERGE DURING THIS TIME. THE CMC PRODUCES LITTLE IF ANY PRECIP FOR THIS AREA AS THE FIRST OF TWO VORT MAXES PROGRESSES RAPIDLY EASTWARD INTO ID/UT BY 18Z SATURDAY, STAYING TOO FAR NORTH TO GENERATE SUFFICIENT LIFT FOR PRECIP IN OUR AREA. THE GFS PROVIDES FAIRLY DECENT AGREEMENT WITH THIS SCENARIO...THOUGH IT IS SLIGHTLY FARTHER SOUTH...CLIPPING AT LEAST THE FAR NORTHERN CWA. THE 00Z ECMWF IS DEEPER WITH THIS TROUGH...ENABLING SCATTERED PRECIP TO BREAK OUT INTO NORTHERN CLARK AND MOHAVE COUNTIES. THE EURO ALSO KEEPS THIS PRECIP AROUND LONGER GIVEN THE SLOWER PROGRESSION OF THE TROUGH...THROUGH 06Z SUNDAY. FOR NOW...BROAD-BRUSHED LOW POPS FOR THE SOUTHERN GREAT BASIN ON SATURDAY. IF PRECIP DOES OCCUR...AMOUNTS SHOULD BE LIGHT IN THIS AREA. MODELS DIVERGE FURTHER INTO THE DAY SUNDAY WITH THE 00Z ECMWF DEVELOPING AN UPSTREAM VORT MAX RAPIDLY PROGRESSING FROM NORTHWEST TO SOUTHEAST THROUGH THE AREA BY 00Z MONDAY. THE GFS DEVELOPS A SIMILAR VORT MAX BUT MUCH FARTHER SOUTH (CLIPPING THE FAR SOUTHERN PARTS OF THE CWA). MEANWHILE, THE CMC DEVELOPS THIS SYSTEM TO THE NORTHEAST OF THE AREA. GOOD NEWS IS ALL THREE PRODUCE VERY LIGHT PRECIP AT MOST WITH THIS VORT MAX. AS SUCH...UNTIL MODELS CONVERGE...KEPT SILENT TO VERY SLIGHT CHANCE POPS IN FOR THE DAY SUNDAY. TEMPERATURES WILL BE SLIGHTLY ABOVE AVERAGE THURSDAY THROUGH SUNDAY...WITH THE WARMEST TEMPS ON FRIDAY AND THE COOLEST TEMPS ON SUNDAY FOLLOWING THE PASSAGE OF THE WEAK SYSTEMS MOVING THROUGH THIS WEEKEND. THEREAFTER, MODELS DEVELOP A HIGH-AMPLITUDE RIDGE ALONG THE WEST COAST AND DRY CONDITIONS FOR OUR AREA. THE CHARACTERISTICS OF THIS RIDGE VARY BASED ON MODEL OF CHOICE, BUT ALL SEEM TO AGREE THAT STRONG NORTHERLY FLOW DEVELOPS IN OUR AREA MONDAY, SUGGESTING THAT WINDS MAY BLOW RATHER STRONGLY IN THE COLORADO RIVER VALLEY. PLENTY OF TIME TO DETERMINE IF THIS COMES TO FRUITION. PERHAPS OF MORE IMPORTANCE, THE SOLUTIONS ARE TRENDING TOWARD A STRONGER SUBTROPICAL RIDGE IN THE EAST PACIFIC NEXT WEEK, WHICH DOES NOT BODE WELL FOR A MORE SOUTHERN STORM TRACK ANY TIME SOON. && .AVIATION...FOR MCCARRAN...MAINLY LIGHT WINDS THROUGH MID-DAY FOLLOWING TYPICAL DIURNAL TRENDS. CIGS WILL LOWER THROUGH THE DAY...DROPPING TO AROUND 8K FEET BY THIS EVENING. A STRAY SHOWER CANNOT BE COMPLETELY RULED OUT DURING THE AFTERNOON. THE WIND FORECAST BECOMES TRICKY THIS AFTERNOON AS THERE COULD BE A BATTLE BETWEEN EAST/NORTHEAST WINDS AND GUSTY SOUTHWEST WINDS IN THE VICINITY OF THE TERMINAL. WITH THE POTENTIAL FOR A SHOWER AND SIGNIFICANT CLOUD COVER...WITH ERR ON THE SIDE OF LIGHTER EAST/NORTHEAST WINDS FOR THE 12Z TAF. IN REALITY...WINDS COULD FAVOR EITHER DIRECTION BETWEEN ROUGHLY 19Z-01Z THIS AFTERNOON. QUIET WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY...WITH ANOTHER VERY SLIGHT CHANCE OF SHOWERS TUESDAY EVENING. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...INCREASING SOUTHWEST WINDS EXPECTED ACROSS THE WESTERN MOJAVE DESERT THIS MORNING (MAINLY SOUTH OF A KNID-KDRA-KSGU LINE). TO THE NORTH...LIGHTER WINDS ARE EXPECTED TO FAVOR TYPICAL DIURNAL TRENDS IN VALLEY LOCATIONS. IT`S UNCLEAR WHETHER THE SOUTHWEST WINDS WILL MAKE IT INTO THE LAS VEGAS VALLEY...WITH KHND BEING THE MOST LIKELY LOCATION IF THEY DO. CIGS ARE EXPECTED TO DROP TO 5-8K FEET AS A WEAK SYSTEM PASSES THROUGH THE REGION. THIS WILL ALSO BRING A SLIGHT CHANCE OF SHOWERS TO THE REGION...MAINLY NORTH OF LAS VEGAS...HOWEVER A FEW STRAY SHOWERS TO THE SOUTH CANNOT BE RULED OUT. QUIET WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY MORNING...WITH ANOTHER SLIGHT CHANCE OF SHOWERS ACROSS THE REGION TUESDAY. && .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED. PLEASE REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD OPERATING PROCEDURES. && $$ SHORT TERM/AVIATION...WOLCOTT LONG TERM.............SHAFER FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
832 PM CST TUE JAN 19 2016 .UPDATE... ISSUED AT 826 PM CST TUE JAN 19 2016 QUICK UPDATE TO EXPAND THE DENSE FOG ADVISORY INTO MCKENZIE...DUNN...GRANT AND SIOUX COUNTIES PER OBSERVED TRENDS 0230 UTC. UPDATE ISSUED AT 721 PM CST TUE JAN 19 2016 WEBCAM AND SURFACE OBSERVATION TRENDS THROUGH 0115 UTC DEPICT VISIBILITY RAPIDLY FALLING ACROSS NORTHWEST AND INTO CENTRAL NORTH DAKOTA WITH STRATUS BUILD DOWN. THUS...HAVE ISSUED A DENSE FOG ADVISORY FOR THESE AREAS THROUGH 16 UTC WEDNESDAY MORNING. THE SPATIAL COVERAGE OF THE ADVISORY IS FITTED TO CURRENT AREAS WITH DENSE FOG...EXTRAPOLATED TO VISIBILITY TRENDS IN THE 21-00 UTC HRRR ITERATIONS. A POTENTIAL EXPANSION OF THE ADVISORY IS POSSIBLE LATER THIS EVENING. UPDATE ISSUED AT 637 PM CST TUE JAN 19 2016 GIVEN TRENDS IN THE 21-23 UTC HRRR ITERATION VISIBILITY FORECASTS...EXPANDED THE MENTION OF FOG TO ALL OF WESTERN AND CENTRAL NORTH DAKOTA TONIGHT INTO WEDNESDAY MORNING. PATCHY DENSE FOG HAS ALREADY DEVELOPED ACROSS NORTHWEST NORTH DAKOTA AS OF 00 UTC...AND EXPECT A SLOW EXPANSION OF FOG WITH STRATUS BUILD DOWN THROUGH THE NIGHT. A DENSE FOG ADVISORY MAY BE NEEDED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 229 PM CST TUE JAN 19 2016 LOOKS LIKE THE VERY COLD AIR WILL TAKE AN EXIT FOR AWHILE. CONCERNS NOW FOR THIS SHORT TERM PERIOD WILL FOCUS ON THE POTENTIAL FOR FOG TONIGHT. MESOSCALE MODELS HAVE BEEN CONSISTENTLY FORECASTING A SHALLOW COOL AND MOIST BOUNDARY LAYER FREE OF CLOUDS ABOVE. HRRR DEVELOPS WIDESPREAD LOW VISIBILITIES THIS EVENING AND OVERNIGHT. SATELLITE TRENDS SO FAR TODAY SHOW THE STRATUS LAYER ERODING IN LOW LEVEL WARM ADVECTION ACROSS WESTERN NORTH DAKOTA. THIS PROCESS WILL BE DISRUPTED THIS EVENING AS SUNSET APPROACHES. DURING THE COOLING HOURS IN THE EVENING EXPECT FOG TO FORM IN THE CLEARING ZONE WITH THE CLOUDS CREEPING BACK WEST. THIS WILL MAKE MIN TEMPERATURES IN THE CLEARING AREA A CHALLENGE. SO FAR HAVE ACCEPTED THE CONSSHORT GUIDANCE GIVING LOWER TEENS ACROSS THE WEST AND SINGLE DIGITS ABOVE ZERO EAST. ON WEDNESDAY THE NEXT SHORTWAVE IN A SERIES OF SHORTWAVES WILL BRING AN INCREASE IN MID/HIGH CLOUDS AND BREAK OF THE BOUNDARY LAYER FOG DURING FORENOON. A SLIGHT CHANCE OF SNOW SEEMS REASONABLE BY LATE AFTERNOON FAR WEST. HIGH WEDNESDAY IN THE 20S TO MID 30S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 229 PM CST TUE JAN 19 2016 WEDNESDAY NIGHT THROUGH THURSDAY...COLD AIR ADVECTION AND A CHANCE OF LIGHT SNOW WILL BEGIN POURING INTO SOUTHWEST NORTH DAKOTA WEDNESDAY EVENING AS A SURFACE LOW AND ASSOCIATED MID LEVEL SHORTWAVE SCOOT FROM SOUTHEAST MONTANA INTO SOUTH DAKOTA. THIS WILL BE FOLLOWED BY ANOTHER SHORTWAVE THURSDAY...AS IT MOVES FROM WEST TO EAST DURING THE DAY. THERE HAD BEEN SOME CONCERN FOR LIGHT FREEZING RAIN WEDNESDAY EVENING...BUT THE NAM/SREF/GFS BUFKIT SOUNDINGS INDICATE THAT IF IT DID DEVELOP...IT WOULD BE BRIEF...WITH A FAIRLY QUICK TRANSITION TO LIGHT SNOW. NOT SEEING AN EXTENDED PERIOD OF UPWARD VERTICAL MOTION WITH WITHIN THE SUPERCOOLED WATER DROPLET REGIME...AND THE TRANSITION TIME FOR ANY GIVEN SOUNDING TO REACH COLDER/HIGHER LEVELS OF SATURATION IS ACHIEVED FAIRLY QUICKLY WEDNESDAY NIGHT. THUS...GIVEN THE BRIEF TIME AND ISOLATED COVERAGE OF LIGHT FREEZING RAIN POTENTIAL...HAVE DECIDED TO STICK WITH THE GIVEN FORECAST WHICH KEEPS A MENTION OF ONLY LIGHT SNOW. WILL REVISIT THE SOUNDINGS AGAIN TONIGHT AND WEDNESDAY FOR ANY SIGNIFICANT CHANGES TO THE ABOVE THINKING. OTHERWISE...CHANCES FOR LIGHT SNOW WILL EXPAND INTO CENTRAL NORTH DAKOTA THROUGH THE DAY THURSDAY. SNOWFALL ACCUMULATIONS THROUGH THURSDAY EVENING ARE FORECAST AROUND A HALF INCH WEST AND CENTRAL...WITH AN ISOLATED SPOT OF ONE INCH IN THE SOUTHWEST. THE CHANCE OF LIGHT SNOW EXITS THE SOUTHERN JAMES RIVER VALLEY THURSDAY EVENING. WITH ONGOING COLD AIR ADVECTION...HIGH TEMPERATURES THURSDAY WILL BE 5 TO 10 DEGREES COLDER FROM WEDNESDAY...WHICH PUTS HIGHS THURSDAY FROM AROUND 10F ABOVE IN THE TURTLE MOUNTAINS TO 25F SOUTHWEST. THURSDAY NIGHT THROUGH SATURDAY...FOLLOWING THE ABOVE SHORTWAVE IS AN UPPER LEVEL RIDGE WHICH WILL SHIFT FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH PLAINS FRIDAY INTO MOST OF SATURDAY. STRONG LOW LEVEL WARM AIR ADVECTION FRIDAY AND SATURDAY WILL RESULT IN A MODERATING TREND ALONG WITH DRY CONDITIONS. HIGHS FRIDAY WILL RANGE FROM AROUND 20 IN THE JAMES RIVER VALLEY TO 40 WEST. BY SATURDAY HIGHS WILL RANGE BETWEEN 30F AND 40F ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE WARMING TREND WILL COME TO AN END SATURDAY EVENING...AS A COLD FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST. THIS LEADS TO A CHANCE OF SNOW AND COLDER TEMPERATURES SUNDAY. HIGHS SUNDAY THROUGH TUESDAY ARE NEARLY THE SAME EACH DAY WITH HIGHS IN THE UPPER TEENS IN THE TURTLE MOUNTAINS TO 20S ELSEWHERE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 826 PM CST TUE JAN 19 2016 WIDESPREAD LIFR/VLIFR CONDITIONS IN FREEZING FOG AND STRATUS EXPANDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH TONIGHT AND INTO WEDNESDAY MORNING. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST /9 AM MST/ WEDNESDAY FOR NDZ001-002-009>011-017>023-034>036-042-045>047-050. && $$ UPDATE...AYD SHORT TERM...WAA LONG TERM...KS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
725 PM CST TUE JAN 19 2016 .UPDATE... ISSUED AT 721 PM CST TUE JAN 19 2016 WEBCAM AND SURFACE OBSERVATION TRENDS THROUGH 0115 UTC DEPICT VISIBILITY RAPIDLY FALLING ACROSS NORTHWEST AND INTO CENTRAL NORTH DAKOTA WITH STRATUS BUILD DOWN. THUS...HAVE ISSUED A DENSE FOG ADVISORY FOR THESE AREAS THROUGH 16 UTC WEDNESDAY MORNING. THE SPATIAL COVERAGE OF THE ADVISORY IS FITTED TO CURRENT AREAS WITH DENSE FOG...EXTRAPOLATED TO VISIBILITY TRENDS IN THE 21-00 UTC HRRR ITERATIONS. A POTENTIAL EXPANSION OF THE ADVISORY IS POSSIBLE LATER THIS EVENING. UPDATE ISSUED AT 637 PM CST TUE JAN 19 2016 GIVEN TRENDS IN THE 21-23 UTC HRRR ITERATION VISIBILITY FORECASTS...EXPANDED THE MENTION OF FOG TO ALL OF WESTERN AND CENTRAL NORTH DAKOTA TONIGHT INTO WEDNESDAY MORNING. PATCHY DENSE FOG HAS ALREADY DEVELOPED ACROSS NORTHWEST NORTH DAKOTA AS OF 00 UTC...AND EXPECT A SLOW EXPANSION OF FOG WITH STRATUS BUILD DOWN THROUGH THE NIGHT. A DENSE FOG ADVISORY MAY BE NEEDED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 229 PM CST TUE JAN 19 2016 LOOKS LIKE THE VERY COLD AIR WILL TAKE AN EXIT FOR AWHILE. CONCERNS NOW FOR THIS SHORT TERM PERIOD WILL FOCUS ON THE POTENTIAL FOR FOG TONIGHT. MESOSCALE MODELS HAVE BEEN CONSISTENTLY FORECASTING A SHALLOW COOL AND MOIST BOUNDARY LAYER FREE OF CLOUDS ABOVE. HRRR DEVELOPS WIDESPREAD LOW VISIBILITIES THIS EVENING AND OVERNIGHT. SATELLITE TRENDS SO FAR TODAY SHOW THE STRATUS LAYER ERODING IN LOW LEVEL WARM ADVECTION ACROSS WESTERN NORTH DAKOTA. THIS PROCESS WILL BE DISRUPTED THIS EVENING AS SUNSET APPROACHES. DURING THE COOLING HOURS IN THE EVENING EXPECT FOG TO FORM IN THE CLEARING ZONE WITH THE CLOUDS CREEPING BACK WEST. THIS WILL MAKE MIN TEMPERATURES IN THE CLEARING AREA A CHALLENGE. SO FAR HAVE ACCEPTED THE CONSSHORT GUIDANCE GIVING LOWER TEENS ACROSS THE WEST AND SINGLE DIGITS ABOVE ZERO EAST. ON WEDNESDAY THE NEXT SHORTWAVE IN A SERIES OF SHORTWAVES WILL BRING AN INCREASE IN MID/HIGH CLOUDS AND BREAK OF THE BOUNDARY LAYER FOG DURING FORENOON. A SLIGHT CHANCE OF SNOW SEEMS REASONABLE BY LATE AFTERNOON FAR WEST. HIGH WEDNESDAY IN THE 20S TO MID 30S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 229 PM CST TUE JAN 19 2016 WEDNESDAY NIGHT THROUGH THURSDAY...COLD AIR ADVECTION AND A CHANCE OF LIGHT SNOW WILL BEGIN POURING INTO SOUTHWEST NORTH DAKOTA WEDNESDAY EVENING AS A SURFACE LOW AND ASSOCIATED MID LEVEL SHORTWAVE SCOOT FROM SOUTHEAST MONTANA INTO SOUTH DAKOTA. THIS WILL BE FOLLOWED BY ANOTHER SHORTWAVE THURSDAY...AS IT MOVES FROM WEST TO EAST DURING THE DAY. THERE HAD BEEN SOME CONCERN FOR LIGHT FREEZING RAIN WEDNESDAY EVENING...BUT THE NAM/SREF/GFS BUFKIT SOUNDINGS INDICATE THAT IF IT DID DEVELOP...IT WOULD BE BRIEF...WITH A FAIRLY QUICK TRANSITION TO LIGHT SNOW. NOT SEEING AN EXTENDED PERIOD OF UPWARD VERTICAL MOTION WITH WITHIN THE SUPERCOOLED WATER DROPLET REGIME...AND THE TRANSITION TIME FOR ANY GIVEN SOUNDING TO REACH COLDER/HIGHER LEVELS OF SATURATION IS ACHIEVED FAIRLY QUICKLY WEDNESDAY NIGHT. THUS...GIVEN THE BRIEF TIME AND ISOLATED COVERAGE OF LIGHT FREEZING RAIN POTENTIAL...HAVE DECIDED TO STICK WITH THE GIVEN FORECAST WHICH KEEPS A MENTION OF ONLY LIGHT SNOW. WILL REVISIT THE SOUNDINGS AGAIN TONIGHT AND WEDNESDAY FOR ANY SIGNIFICANT CHANGES TO THE ABOVE THINKING. OTHERWISE...CHANCES FOR LIGHT SNOW WILL EXPAND INTO CENTRAL NORTH DAKOTA THROUGH THE DAY THURSDAY. SNOWFALL ACCUMULATIONS THROUGH THURSDAY EVENING ARE FORECAST AROUND A HALF INCH WEST AND CENTRAL...WITH AN ISOLATED SPOT OF ONE INCH IN THE SOUTHWEST. THE CHANCE OF LIGHT SNOW EXITS THE SOUTHERN JAMES RIVER VALLEY THURSDAY EVENING. WITH ONGOING COLD AIR ADVECTION...HIGH TEMPERATURES THURSDAY WILL BE 5 TO 10 DEGREES COLDER FROM WEDNESDAY...WHICH PUTS HIGHS THURSDAY FROM AROUND 10F ABOVE IN THE TURTLE MOUNTAINS TO 25F SOUTHWEST. THURSDAY NIGHT THROUGH SATURDAY...FOLLOWING THE ABOVE SHORTWAVE IS AN UPPER LEVEL RIDGE WHICH WILL SHIFT FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH PLAINS FRIDAY INTO MOST OF SATURDAY. STRONG LOW LEVEL WARM AIR ADVECTION FRIDAY AND SATURDAY WILL RESULT IN A MODERATING TREND ALONG WITH DRY CONDITIONS. HIGHS FRIDAY WILL RANGE FROM AROUND 20 IN THE JAMES RIVER VALLEY TO 40 WEST. BY SATURDAY HIGHS WILL RANGE BETWEEN 30F AND 40F ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE WARMING TREND WILL COME TO AN END SATURDAY EVENING...AS A COLD FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST. THIS LEADS TO A CHANCE OF SNOW AND COLDER TEMPERATURES SUNDAY. HIGHS SUNDAY THROUGH TUESDAY ARE NEARLY THE SAME EACH DAY WITH HIGHS IN THE UPPER TEENS IN THE TURTLE MOUNTAINS TO 20S ELSEWHERE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 721 PM CST TUE JAN 19 2016 WIDESPREAD LIFR/VLIFR CONDITIONS IN FREEZING FOG AND STRATUS EXPANDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH TONIGHT AND INTO WEDNESDAY MORNING. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST WEDNESDAY FOR NDZ001-002- 009>011-019>023-034>036-046-047-050. && $$ UPDATE...AYD SHORT TERM...WAA LONG TERM...KS AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
840 PM EST TUE JAN 19 2016 .SYNOPSIS... AN UPPER LEVEL TROUGH ALONG WITH AN UPPER LEVEL DISTURBANCE WILL COMBINE TO BRING SNOW TO THE AREA WEDNESDAY. HIGH PRESSURE AND DRY AIR WILL RETURN FOR THURSDAY...UNTIL A LARGE AREA OF LOW PRESSURE BRINGS ANOTHER WINTER SYSTEM TO THE REGION ON FRIDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... HIGH CLOUDS ARE SPREADING INTO THE FORECAST AREA THIS EVENING...AND RADAR ECHOES HAVE EXTENDED INTO SOUTHWEST INDIANA. SOME OF THESE ECHOES ARE VIRGA...WITH THE INITIAL AREAS OF SNOW JUST NOW REACHING SOUTHERN ILLINOIS. BASED ON CURRENT TRENDS AND RECENT HRRR/RAP FORECAST CYCLES...THE TIMING FOR SNOW WAS SPED UP SLIGHTLY. ALSO...POPS WERE INCREASED TO 100 PERCENT FOR MUCH OF THE FORECAST AREA. THE LATEST GUIDANCE SUGGESTS THAT THE CURRENT SNOWFALL FORECAST IS STILL ON TRACK...FALLING VERY CLOSE TO THE SREF MEAN...AND IN BETWEEN THE HIGHER NAM AND LOWER RAP SOLUTIONS. PREVIOUS DISCUSSION > CURRENTLY MOSTLY CLEAR SKIES WITH SOME PASSING CIRRUS AS THE NEXT UPPER LEVEL SYSTEM CAN CLEARLY BE SEEN ON VISIBLE OFF TO OUR WEST. WEDNESDAY MORNING AN UPPER LEVEL TROUGH WILL DIVE SOUTHEAST AND PUSH INTO OUR FAR WESTERN ZONES BETWEEN 4 AM AND 7 AM. OMEGA VALUES ON BOTH THE GFS AND NAM SHOW WEAK LIFT MOVING ACROSS THE AREA RIGHT AROUND 6 AM ALONG WITH ISENTROPIC UPGLIDE COMMENCING. THINK THE ONSET OF SNOW MIGHT BE DELAYED A BIT AS GFS AND NAM FORECAST SOUNDINGS SHOW DRY AIR AROUND 750 MB SLOWLY ERODING WEDNESDAY MORNING. THIS MAKES SENSE AS 12 Z 700 MB ANALYSIS SHOWED DEWPOINT DEPRESSIONS OF GREATER THAN 20 DEGREES JUST OFF TO OUR WEST. LATEST SUITE OF HIGH RES AND GLOBAL MODELS HAVE SHOWN A SLIGHT INCREASE IN AMOUNTS OF SNOWFALL ACROSS THE AREA BUT AM EXPECTING 1-2 INCHES WITH HIGHER AMOUNTS POSSIBLE ACROSS THE SOUTHWEST OF THE CWA. THE TIMING OF THE SNOWFALL ALSO LOOKS TO OCCUR DURING THE MORNING COMMUTE. GIVEN THE POTENTIAL IMPACTS DURING THE MORNING COMMUTE AND SLIGHTLY HIGHER TOTALS HAVE EXTENDED THE WINTER WEATHER ADVISORY ONE TIER OF COUNTIES NORTH. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... WEDNESDAY MORNING WILL START OFF WITH SNOW SPREADING ACROSS THE CWA WITH HIGHER TOTALS FORECASTED ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS ON THE NAM AND GFS THEN SHOW THE SNOW STARTING TO COME TO AN END WEST TO EAST BETWEEN NOON AND 2 PM. ACROSS OUR FAR EASTERN COUNTIES SNOW SHOULD COME TO AN END BY 7 PM. FORECAST SOUNDINGS ON BOTH THE GFS AND NAM ALSO SHOW DRY AIR STARTING TO MOVE IN AT 500 MB AS THE MAIN SHORTWAVE MOVES OVERHEAD. THE DGZ APPEARS TO BE BETWEEN 550 AND 700 MB. THE DEWPOINT AND TEMPERATURE LINES ON THE FORECAST SOUNDINGS CONTINUE TO PULL APART IN THE AFTERNOON. THIS WILL BRING AN END TO THE SNOW. THE TEMPERATURE PROFILE IS ALSO ISOTHERMAL RIGHT AROUND -10 DEGREES FROM 900 TO 700 MB. A LITTLE COLDER PROFILE WILL KEEP THE SNOW GOING SLIGHTLY LONGER AS ICE CRYSTALS WILL BE ABLE TO GROW WHERE AS A SLIGHTLY WARMER PROFILE WOULD FAVOR A QUICKER END TO THE SNOW AND A POSSIBLE BRIEF PERIOD OF DRIZZLE. FOR NOW HAVE LEFT THE MENTION OF DRIZZLE OUT AS CONFIDENCE REMAINS LOW. WEDNESDAY EVENING SNOW WILL COME TO AN END AS A WEAK COLD FRONT CROSSES THE AREA. SURFACE HIGH PRESSURE WILL THEN MOVE OVERHEAD THURSDAY MORNING ALLOWING WINDS TO GO CALM. THURSDAY MORNING THE GFS... EURO AND NAM ALL SHOW A CIRRUS SHIELD MOVING IN FROM THE SOUTHWEST ALONG WITH SOME LOW CLOUDS LINGERING. GIVEN THE ABOVE... LOW TEMPERATURES THURSDAY MORNING WILL LIKELY BE A TAD WARMER THAN WEDNESDAY MORNINGS TEMPS. DURING THE DAY THURSDAY CIRRUS WILL CONTINUE WITH SURFACE RIDGING WEAKENING ACROSS THE AREA AS THE NEXT SYSTEM APPROACHES FROM THE WEST. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MAIN FOCUS IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR A WINTER STORM TO AFFECT THE OHIO VALLEY REGION. THE IMPETUS FOR WHAT WILL DEVELOP INTO A CLOSED MID LEVEL CIRCULATION EITHER OVER THE TN VLY OR THE DEEP SOUTH IS STILL OFF THE WEST COAST ATTM...SO CAUTION MUST BE USED IN THE FORECAST DUE TO THE OSCILLATIONS IN THE POSITION AND TRACK OF THE MID LEVEL CIRCULATION. MODELS TEND TO HAVE ISSUES WITH THE CLOSING OFF OF SUCH SYSTEMS...AND GIVEN THAT THE ENERGY IS STILL OFF THE WEST COAST...THERE WILL BE TIME FOR OSCILLATIONS TO CONTINUE UNTIL PERHAPS 12Z WEDNESDAY WHEN THE ENERGY WILL BE FULLY SAMPLED. THAT BEING SAID...OF THE MAIN OPERATIONAL MODELS FROM THE 01.19.12Z RUN...THE ECMWF HAS TAKEN A MORE SOUTHERN TRACK ACROSS THE DEEP SOUTH VERSUS THE OTHER MODELS (NAM...GFS...AND CMC). AS TO NOT JUMP ON THE PURE 12Z ECMWF SOLUTION...WHICH WOULD BRING A PCPN SHIELD/MID LEVEL DEFORMATION AXIS ONLY AS FAR NORTH AS THE OHIO RIVER...HAVE TAKEN A BLEND OF THE 12Z GFS AND THE PREVIOUS 00Z ECMWF WHICH KEEPS SOME CONTINUITY TO THE GOING FORECAST AND ALLOWS FOR SOME POTENTIAL FOR A MORE NORTHERN TRACK TO BE A POSSIBLE SOLUTION. THUS...THE CURRENT FORECAST WILL ALLOW PCPN SHIELD/MID LVL DEFORMATION AXIS PUSH NORTHWARD TOWARD THE OHIO RIVER THURSDAY NIGHT...ALLOWING IT TO PIVOT AS FAR NORTH/NORTHWEST AS THE I-71 CORRIDOR...AND THEN ALLOW IT TO SHIFT EAST FRIDAY NIGHT INTO SATURDAY AS A COASTAL LOW/ENERGY TRANSFER TAKES PLACE. BASED ON THIS SCENARIO...PCPN SHOULD REMAIN AS SNOW WITH THE POTENTIAL FOR SIGNIFICANT SNOW ACCUMULATIONS ALONG AND SOUTHEAST OF THE I-71 CORRIDOR AND PARTICULARY ALONG AND SOUTH OF THE OHIO RIVER VALLEY. THUS...AT THIS JUNCTURE...4 OR MORE INCHES OF SNOW MAY BE POSSIBLE ALONG AND SOUTH OF THE I-71 CORRIDOR WITH 6 OR MORE INCHES POSSIBLE ALONG AND SOUTH OF THE OHIO RIVER. AGAIN...A TRACK FARTHER SOUTH WOULD ONLY IMPACT LOCATIONS ALONG AND SOUTH OF THE OHIO RIVER...AND A TRACK FARTHER NORTH WOULD PUSH THE THREAT TOWARD THE I-71 CORRIDOR. AS THE COASTAL LOW TAKES SHAPE AND MOVES NEAR AND OFF THE NEW ENGLAND COAST SATURDAY AFTERNOON AND NIGHT...PCPN WILL TAPER OFF OVER THE REGION AS SURFACE HIGH PRESSURE BUILDS BACK INTO THE OHIO VALLEY. AS FOR TEMPERATURES...HAVE TAKEN BLEND OF PREVIOUS FORECAST AND THE 12Z GFS/00Z ECMWF. SOME ADJUSTMENTS MAY HAVE TO BE MADE TO CURRENT VALUES DEPENDING ON WHERE AND THE AMOUNT OF SNOW COVER WHICH MAY FALL...WHICH WILL HAVE AN ALBEDO EFFECT/RADIATIONAL COOLING EFFECT. FOR SUNDAY INTO MONDAY...HIGH PRESSURE WILL MOVE OFF TO THE EAST AS THE NEXT LOW PRESSURE SYSTEM AND FRONT MOVE IN FROM THE WEST. THERE ARE SOME TIMING AND STRENGTH DIFFERENCE AT THIS POINT...SO WILL BRING A GRADUAL CHANCE OF PCPN FROM WEST TO EAST MONDAY AFTERNOON INTO MONDAY NIGHT...WITH THE CHANCE CONTINUING INTO TUESDAY AS THE SYSTEM MOVES THROUGH. TEMPERATURES WILL BE CRITICAL TO PTYPE. CURRENTLY HAVE RAIN/SNOW FOR NORTHERN AREAS AND RAIN FOR SOUTHERN AREAS...WITH A CHANGEOVER TO ALL SNOW ON TUESDAY IN THE WAKE OF THE LOW AND FRONT. A BLEND OF THE TEMPERATURES HAVE BEEN USED WITH HIGHS IN THE 30S TO AROUND 40 AND LOWS MAINLY IN THE 30S. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS WILL CONTINUE THROUGH THE MAJORITY OF THE OVERNIGHT HOURS...BEFORE SNOW MOVES INTO THE REGION EARLY WEDNESDAY MORNING. CLOUDS WILL GRADUALLY LOWER AND THICKEN (ESPECIALLY AFTER MIDNIGHT)...BUT SHOULD REMAIN VFR UNTIL AFTER THE SNOW BEGINS. ONCE SNOW STARTS...CONDITIONS WILL DETERIORATE RAPIDLY. IFR VISIBILITIES ARE A CERTAINTY...AS WELL AS MVFR (POSSIBLY IFR) CEILINGS. WINDS WILL REMAIN VERY LIGHT THROUGH THE ENTIRE FORECAST PERIOD. AFTER THE SNOW ENDS...MVFR CEILINGS WILL LIKELY PERSIST THROUGH THE REST OF THE DAY...AND POSSIBLY INTO THE OVERNIGHT HOURS. OUTLOOK...MVFR CEILINGS MAY CONTINUE THROUGH WEDNESDAY NIGHT AND INTO EARLY THURSDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED WITH PRECIPITATION ON FRIDAY INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST WEDNESDAY FOR OHZ070>072-077>081-088. KY...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST WEDNESDAY FOR KYZ089>100. IN...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST WEDNESDAY FOR INZ066-073>075-080. && $$ SYNOPSIS...HAINES NEAR TERM...HAINES/HATZOS SHORT TERM...HAINES LONG TERM...HICKMAN AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS Tulsa OK
909 PM CST TUE JAN 19 2016 ...UPDATE... .DISCUSSION... Precipitation across far eastern OK and northwest AR has been convection in nature...resulting in pockets of brief moderate sleet/freezing rain this evening. This has made for very slick conditions across the region...especially in and around the Fort Smith area and into parts of Madison county. HRRR trends are for the heavier precipitation to shift east of the region after 06z...although could see a few more hours of light freezing drizzle. Will leave the winter weather advisory as is for now...but it may end of being cancelled a bit earlier than 12z. && .PRELIMINARY POINT TEMPS/POPS... TUL 26 40 33 40 / 40 0 40 40 FSM 31 43 34 42 / 70 0 40 60 MLC 31 43 36 44 / 50 0 30 50 BVO 24 39 29 38 / 30 0 40 40 FYV 28 40 31 38 / 80 0 40 60 BYV 26 38 28 36 / 80 0 30 60 MKO 30 40 34 41 / 60 0 40 50 MIO 25 40 30 38 / 60 0 40 50 F10 29 40 34 42 / 50 0 30 40 HHW 35 47 38 48 / 50 0 50 60 && .TSA Watches/Warnings/Advisories... OK...Winter Weather Advisory until 6 AM CST Wednesday for OKZ057-058- 062-063-068-069-072. AR...Winter Weather Advisory until 6 AM CST Wednesday for ARZ001-002- 010-011-019-020-029. && $$ SHORT TERM...18
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
745 PM CST TUE JAN 19 2016 .DISCUSSION... LATEST SURFACE ANALYSIS DEPICTS SNOW ACROSS THE NORTHERN HALF OF MO. FREEZING RAIN AND SOME SLEET OVER SRN MO...SOME FRZ RAIN ACROSS NRN AR. 00Z OHX SOUNDING REVEALED 850 MB TEMPS THAT WERE SLIGHTLY WARMER THAN THE MODELS. WET BULB ZERO PROFILES AT THE 850 MB LEVEL SHOWS A RATHER IMPRESSIVE WEDGE OF WARMING ACROSS AR. PORTIONS OF NRN AR AND SRN MO SHOW FRZ RA WITH TEMPS IN THE LOWER TO MID 20S...A TESTAMENT AS TO THE DEGREE OF WARM WEDGING THAT IS ON GOING. SFC LOW IS CURRENTLY LOCATED OVER ERN OK. SLIGHT INCREASE IN STRENGTH IS EXPECTED WITH THE WARM AIR IN THE 800MB TO 900 MB LEVEL WORKING EASTWARD. THIS WARMER AIR MAY VERY WELL MAKE IT INTO OUR SOUTHWESTERN COUNTIES PRIOR TO 12Z. THUS...I WILL GO AHEAD AND INCLUDE MORE IN THE WAY OF SLEET AND FREEZING RAIN ACROSS OUR SOUTHWESTERN AND SOUTH CENTRAL AREAS. LATEST HRRR SHOWS PATCHY LIGHT PRECIP MAKING IT ACROSS THE TN RIVER AND REACHING THE GROUND JUST AFT MIDNIGHT. THE MORE SIGNIFICANT PRECIP APPEARS TO MAKE IT ACROSS THE TN RIVER RIGHT AROUND 6 AM. BASED ON THE LATEST 18Z NAM SOUNDINGS...IT STILL LOOKS LIKE ALL SNOW NORTH OF I-40. BUT...THAT SOUTHWEST AREA IS A CONCERN AND MORE IN THE WAY OF SLEET AND FREEZING RAIN COULD FALL. AGAIN...WILL OPT TO MODIFY THE WX GRIDS TO REFLECT THIS ACROSS SOUTHWEST AND SOUTHCENTRAL AREAS. SFC TEMPS STILL EXPECTED TO WARM ABOVE FREEZING ACROSS THE SOUTHWEST BY 9AM...AND THEN ALL BUT THE PLATEAU AREA BY NOON. UPDATE OUT SHORTLY. && .AVIATION... 18Z TAF DISCUSSION. SURFACE LOW IN TEXAS WILL MOVE THIS WAY TONIGHT WITH INCREASING CLOUDS ACROSS THE AREA WITH SNOW STARTING AT CLARKSVILLE AFTER MIDNIGHT AND AT NASHVILLE BY 11Z. ACCUMULATING SNOW WILL THEN WORK EASTWARD ACROSS THE MID STATE DURING THE DAY. THERE COULD BE BRIEF PERIOD OF FREEZING RAIN FROM INTERSTATE 40 NORTHWARD BUT FROM WHAT I`VE SEEN IT LOOKS LIKE MAINLY A SNOW EVENT BASED ON FORECAST SOUNDINGS. SHOULD SEE PRECIP TAPER OFF DURING THE AFTERNOON FROM THE WEST. NEEDLESS TO SAY FLYING CONDITIONS WILL GO DOWNHILL AFTER MIDNIGHT TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 23 36 30 41 37 / 80 100 20 80 100 CLARKSVILLE 23 35 27 39 33 / 100 90 20 70 90 CROSSVILLE 19 32 28 40 37 / 50 100 20 70 90 COLUMBIA 25 37 33 44 38 / 60 100 20 90 100 LAWRENCEBURG 24 36 33 44 39 / 50 100 20 80 100 WAVERLY 24 37 30 40 34 / 100 90 20 80 90 && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST WEDNESDAY FOR BEDFORD-CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND- DAVIDSON-DE KALB-DICKSON-FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON- HUMPHREYS-JACKSON-LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY- OVERTON-PERRY-PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART- SUMNER-TROUSDALE-VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON. && $$ SHORT TERM/AVIATION........31 LONG TERM..................21
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
914 PM CST TUE JAN 19 2016 .DISCUSSION... SFC ANALYSIS AT 03Z SHOWED COLD FRONT STRETCHING FROM N TX THROUGH W C TX WITH A FEW SHOWERS ALONG IT SE OF THE METROPLEX. BASED ON LATEST HRRR TRENDS AND 00Z NAM...FRONT SHOULD CONTINUE TO PUSH SOUTH INTO THE AREA THROUGH THE MORNING. FRONT MAY BE SLOW TO RETURN NORTH AS A WARM FRONT TOMORROW. STRONGER SHORT WAVE TROUGH PUSHES BY ON THURSDAY SO THINK THAT WILL SUPPORT BETTER RAIN CHANCES AND PROBABLY SOME THUNDERSTORMS GIVEN ENOUGH INSTABILITY. THAT SAID...MAY GET A DRY SLOT TO PUSH THROUGH AND KICK STORMS EAST. MAIN CHANGES TO THE FORECAST WERE TO UPDATE T/TD AS WELL AS POP/WX/QPF FOR ONGOING TRENDS AND NEW MODEL GUIDANCE. 39 && .PREV DISCUSSION... /ISSUED 600 PM CST TUE JAN 19 2016/ AVIATION... VFR CEILINGS THIS EVENING SHOULD GRADUALLY BECOME MVFR BETWEEN 06-09Z AS THE SOUTHERLY FLOW CONTINUES TO DRAW ADDITIONAL LOW LEVEL MOISTURE IN TO THE AREA AHEAD OF AN APPROACHING COLD FRONT. OVERNIGHT WINDS WILL BE LIGHT...BUT SHOULD PRODUCE ENOUGH MIXING IN THE BOUNDARY LAYER TO INHIBIT WIDESPREAD FOG FORMATION. A WEAK COLD FRONT SHOULD MOVE ACROSS THE WESTERN TERMINALS BETWEEN 07-09Z AND THE HOUSTON METRO AREA BETWEEN 12-15Z...AND OFF THE COAST BETWEEN 15-18Z...RESULTING IN A N/NW WIND SHIFT. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT AS IT SAGS SOUTHWARD...SO I CONTINUE TO CARRY A VCSH MENTION FOR ALL TERMINALS. THE FRONT IS EXPECTED TO REACH THE COAST...HOWEVER THE NORTH FLOW WILL BE SHORT LIVED AT TERMINALS TO THE SOUTH OF I-10. WINDS SHOULD BECOME LIGHT AND VARIABLE OVER THE HOUSTON METRO AREA AND VEER TO THE NORTHEAST AT TERMINALS CLOSER TO THE COAST BY TOMORROW AFTERNOON. 44 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 45 60 54 65 38 / 30 10 30 40 10 HOUSTON (IAH) 53 66 57 70 41 / 20 30 30 50 10 GALVESTON (GLS) 58 63 59 69 44 / 20 30 10 40 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1206 PM CST MON JAN 18 2016 .AVIATION... /18Z TAFS/ NO AVIATION CONCERNS ARE EXPECTED IN THE FIRST 12-18 HOURS OF THE TAF FORECAST WITH VFR CONDITIONS UNDERNEATH DRY NORTHWEST FLOW ALOFT. A SURFACE RIDGE CENTERED FROM NORTHEAST OKLAHOMA TO THE MID MISSISSIPPI VALLEY WILL CONTINUE MOVING SLOWLY EAST THROUGH THE DAY. ALL AIRPORTS SHOULD SEE N/NE WINDS 4-6 KTS VEER SE BY LATE AFTERNOON OR EARLY EVENING. DFW AIRPORT SHOULD BE ABLE TO GO TO A SOUTH FLOW BY THEN. THE BIGGEST CHALLENGE WILL BE THE ARRIVAL OF IFR CIGS INTO ALL THE AIRPORTS BY...OR SHORTLY AFTER SUNRISE WITH A SHALLOW FRONTAL INVERSION REMAINING IN PLACE. WARMING TEMPERATURES AND MIXING SHOULD HELP CIGS RISE INTO THE MVFR CATEGORY BY MIDDAY TUESDAY...BEFORE SCATTERING IN THE AFTERNOON. LEE SURFACE CYCLOGENESIS WILL DEEPEN TO OUR NORTHWEST TONIGHT WITH INCREASING SOUTH WINDS 10-15 KTS BY SUNRISE TUESDAY. SUSTAINED WIND SPEEDS INCREASE TO BETWEEN 15-20 KTS WITH HIGHER GUSTS BY MIDDAY TUESDAY. AN APPROACHING SHORTWAVE DISTURBANCE AND ASSOCIATED COLD FRONT ARRIVE TUESDAY EVENING WELL BEYOND THIS FORECAST. SHOWER ACTIVITY ALONG THE FRONT WILL LIKELY OCCUR EAST OF ALL AIRPORTS WHERE BETTER MOISTURE RESIDES. 05/ && .UPDATE... SUNNY SKIES AND COOL CONDITIONS ARE IN STORE FOR THE REMAINDER OF THE MLK HOLIDAY. TEMPERATURES THIS MORNING STARTED OUT IN THE LOWER 20S TO LOWER 30S AND WILL REACH THE 40S TO MID 50S THIS AFTERNOON. MADE SOME MINOR ADJUSTMENTS TO AFTERNOON HIGHS BASED ON CURRENT TEMPS AND TRENDS BUT OTHERWISE NO SIGNIFICANT CHANGES WERE NEEDED TO THE FORECAST. JLDUNN && .PREV DISCUSSION... /ISSUED 248 AM CST MON JAN 18 2016/ COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY PROGRESSIVE. MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING. IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE... HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID 50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER. SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH. WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR. HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S. A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID TO UPPER 60S AREAWIDE. DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 43 40 61 38 59 / 0 0 5 20 5 WACO, TX 47 41 64 42 63 / 0 0 0 10 5 PARIS, TX 43 35 55 38 56 / 0 0 10 40 5 DENTON, TX 42 38 60 35 57 / 0 0 5 20 5 MCKINNEY, TX 42 37 58 37 57 / 0 0 5 20 5 DALLAS, TX 44 40 61 39 59 / 0 0 5 20 5 TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5 CORSICANA, TX 47 42 61 44 61 / 0 0 5 20 5 TEMPLE, TX 49 41 66 44 64 / 0 0 0 10 5 MINERAL WELLS, TX 43 36 63 34 61 / 0 0 0 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/82
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1129 AM CST MON JAN 18 2016 .AVIATION... VFR CONDITIONS IN PLACE AT KCDS AND WILL REMAIN SO THROUGH THE DAY AS VFR CLOUD DECK DISSIPATES. KLBB AND KPVW REMAIN UNDER LIFR CEILINGS WHICH WILL TAKE A BIT LONGER TO BURN OFF. TIMING REMAINS UNCERTAIN WHEN THIS WILL OCCUR AS WESTERN EDGE HAS QUICKLY DISSIPATED BUT STARTED TO SLOW DOWN THE FURTHER EAST THE CLEARING LINE TRIED TO PUSH. CONFIDENCE IS LOW REGARDING WHEN KLBB/KPVW WILL IMPROVE TO VFR SO TIMING IN THE TAF REMAINS UNCERTAIN. VFR CONDITIONS WILL LAST THROUGH THE AFTERNOON INTO TONIGHT BUT THERE IS A CHANCE OF SEEING LIFR CEILINGS DEVELOP AGAIN AT KPVW AND KLBB. CONFIDENCE IS TOO LOW TO INCLUDE AT THIS TIME BUT THE POSSIBILITY WILL BE THERE. JORDAN && .PREV DISCUSSION... /ISSUED 523 AM CST MON JAN 18 2016/ AVIATION... LIFR TO IFR FOG HAVE PERSISTED AT KLBB AND KPVW RESPECTIVELY. AT KCDS...VFR FOG HAPPENS ON OCCASION. HOWEVER...LIFR TO IFR CIGS WERE OCCURRING AT ALL THREE TAF SITES. EXPECT CONDITIONS TO IMPROVE TO VFR BY LATE MORNING/EARLY AFTERNOON. VFR DECKS WILL RETURN BY THE EVENING-OVERNIGHT. OTHERWISE...LIGHT AND VARIABLE WINDS WILL VEER TO THE SOUTH SOUTHWEST THIS AFTERNOON AT 10-12 KTS...BEFORE DECLINING A BIT SHORTLY AFTER SUNSET. PREV DISCUSSION... /ISSUED 214 AM CST MON JAN 18 2016/ SHORT TERM... THE COLD FRONT THAT MOVED IN ACROSS THE SOUTH PLAINS AND ROLLING PLAINS YESTERDAY EVENING...USHERED IN LOW CLOUDS AND AIDED IN THE DEVELOPMENT OF PATCHY AND AREAS /AND AT TIMES LOCALLY DENSE/ FOG. JUST FOR PROSPECTIVE...KLBB REPORTED VIS DOWN TO 5SM DUE TO FOG WHERE AT KPVW IT WAS DOWN TO 3/4SM AT ONE POINT. MOST MODEL SOLUTIONS SUCH AS THE HRRR AND NAM HINT AT DENSE FOG BEING MORE PREVALENT NEAR THE TEXAS AND NEW MEXICO BORDER EARLY THIS MORNING AND SPREADING EASTWARD TO NEAR KLBB BY LATER THIS MORNING. WITH KCVN AND KCVS REPORTING 1/4SM...THE AFOREMENTIONED MODELS COULD HAVE A GOOD HANDLE ON THE SITUATION. WE WILL SEE LATER ON IN THE SHIFT IF A DENSE FREEZING FOG ADVISORY WILL BE REQUIRED. DESPITE THE STRATUS DECK...TEMPS STILL MANAGED TO CRATER INTO THE 20S PER 08Z METARS...WHICH SUGGESTS THIS COLD AIRMASS IS A BIT POTENT. BY MID- LATE MORNING...THE SFC RIDGE RESPONSIBLE FOR DRIVING THE COLD FRONT AND HENCE PROVIDING THE CAA WILL BE GRADUALLY EXITING THE REGION TO THE EAST...WHILST SFC LEE TROUGHING BECOMES ESTABLISHED. THIS WILL LEAD TO SFC WINDS VEERING TO THE S-SW...WHICH IS A WIND COMPONENT FAVORABLE FOR SCOURING OUT LOW CLOUDS AND FOG. MOST AREAS WILL THEREFORE SEE THE SUN BY AT LEAST LATE AFTN. TEMPS TODAY WILL WARM TO AROUND SEASONAL NORMS /50S/ WITH THE EXCEPTION OF THE ROLLING PLAINS /40S/...WHERE CLOUDS WILL BE SLOWEST TO DEPART. AN AMPLIFIED UA RIDGE TO OUR WEST WILL BE TRANSLATING TOWARDS THE REGION TODAY...AND FILTER IN SOME HIGH LEVEL CLOUDINESS BY THIS EVENING- TONIGHT...MAKING FOR A WARMER NIGHT /30S/. LONG TERM... A MILD...DRY...AND PERIODICALLY BREEZY PATTERN SETTING UP THIS WEEK. SPLIT PROGRESSIVE FLOW OVER THE CONUS THIS WEEK WILL BRING A SERIES OF SHORT WAVE TROUGHS ACROSS THE PLAINS...MOST NOTABLY TUESDAY AND AGAIN WEDNESDAY BEFORE LARGER-AMPLITUDE UPPER RIDGING MOVES FROM THE ROCKIES TO THE PLAINS LATE WEEK INTO NEXT WEEKEND. OVERALL...WILL FAVOR THE WARMER END OF MOS GUIDANCE...AS THAT END HAS BEEN SUPERIOR FOR MUCH OF THE LAST SEVERAL MONTHS AND MORE RECENTLY OVER THE LAST WEEK OR SO. PRECIP CHANCES LOOK NEAR NIL. THE BEST CHANCE STILL APPEARS TO BE WEDNESDAY NIGHT...BUT THAT ALSO CONTINUES TO LOOK TO BE EAST OF THE REGION. LOCAL SUPERBLEND INITIALIZATION HAS BROUGHT SLIGHT CHANCE MENTION BACK TO THE ROLLING PLAINS...BUT STILL CONSIDER THAT SCENARIO HIGHLY UNLIKELY AND HAVE KEPT PRECIP MENTION OUT. TEMPS SHOULD BE AT OR ABOVE TO WELL ABOVE CLIMATOLOGY WITH THE EXCEPTION OF THURSDAY WHEN AMPLIFICATION OF THE UPPER FLOW WILL ALLOW SOME COLDER AIR TO SPILL DOWN THE PLAINS. EVEN THEN...TEMPS ARE LIKELY TO ONLY BE A FEW DEGREES OR SO BELOW NORMS. TEMPS REBOUND QUICKLY WITH THE RIDGING MOVING OVERHEAD WITH THE WARMEST DAY OF THE WEEK LOOKING TO BE SATURDAY WITH THE RIDGE AXIS OVERHEAD. && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1100 AM CST MON JAN 18 2016 .UPDATE... SUNNY SKIES AND COOL CONDITIONS ARE IN STORE FOR THE REMAINDER OF THE MLK HOLIDAY. TEMPERATURES THIS MORNING STARTED OUT IN THE LOWER 20S TO LOWER 30S AND WILL REACH THE 40S TO MID 50S THIS AFTERNOON. MADE SOME MINOR ADJUSTMENTS TO AFTERNOON HIGHS BASED ON CURRENT TEMPS AND TRENDS BUT OTHERWISE NO SIGNIFICANT CHANGES WERE NEEDED TO THE FORECAST. JLDUNN && .AVIATION... /ISSUED 600 AM CST MON JAN 18 2016/ THE ONLY AVIATION WEATHER CONCERN WITH THIS TAF PACKAGE WILL BE THE POTENTIAL FOR SOME BRIEF MVFR TO IFR CEILINGS THIS MORNING. AS OF 530 AM...LIFR CEILINGS/VISIBILITY REMAINED OVER THE WEST TEXAS AND SOUTHERN OKLAHOMA WHERE MOISTURE WAS TRAPPED UNDER THE SHALLOW FRONTAL INVERSION. THE NAM AND GFS BOTH KEEP THE BEST MOISTURE ON THE 925 MB SURFACE JUST TO THE NORTH AND WEST OF THE TAF SITES THROUGH MIDDAY. SO FOR NOW HAVE DECIDED TO JUST MENTION SOME SCATTERED LOW CLOUDS THROUGH THE MORNING AT ALL NORTH/CENTRAL TEXAS TERMINALS BUT WILL HAVE TO WATCH CLOUD TRENDS CLOSELY. OTHERWISE...EXPECT SCATTERED HIGH CLOUDS THIS AFTERNOON AND EVENING. MVFR CEILINGS WILL BE LIKELY BY SUNRISE TUESDAY AS LOW LEVEL MOISTURE SURGES NORTHWARD. A NORTH WIND THIS MORNING WILL TURN TO THE EAST/SOUTHEAST THIS AFTERNOON AND SOUTH TONIGHT. WIND SPEEDS WILL REMAIN BELOW 10 KNOTS THROUGH TONIGHT BUT WILL INCREASE BETWEEN 13 AND 15 KNOTS BY SUNRISE TUESDAY. 79 && .PREV DISCUSSION... /ISSUED 248 AM CST MON JAN 18 2016/ COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY PROGRESSIVE. MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING. IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE... HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID 50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER. SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH. WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR. HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S. A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID TO UPPER 60S AREAWIDE. DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 43 40 61 38 59 / 0 0 5 20 5 WACO, TX 47 41 64 42 63 / 0 0 0 10 5 PARIS, TX 43 35 55 38 56 / 0 0 10 40 5 DENTON, TX 42 38 60 35 57 / 0 0 5 20 5 MCKINNEY, TX 42 37 58 37 57 / 0 0 5 20 5 DALLAS, TX 44 40 61 39 59 / 0 0 5 20 5 TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5 CORSICANA, TX 47 42 61 44 61 / 0 0 5 20 5 TEMPLE, TX 49 41 66 44 64 / 0 0 0 10 5 MINERAL WELLS, TX 43 36 63 34 61 / 0 0 0 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/82
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
600 AM CST MON JAN 18 2016 .AVIATION... THE ONLY AVIATION WEATHER CONCERN WITH THIS TAF PACKAGE WILL BE THE POTENTIAL FOR SOME BRIEF MVFR TO IFR CEILINGS THIS MORNING. AS OF 530 AM...LIFR CEILINGS/VISIBILITY REMAINED OVER THE WEST TEXAS AND SOUTHERN OKLAHOMA WHERE MOISTURE WAS TRAPPED UNDER THE SHALLOW FRONTAL INVERSION. THE NAM AND GFS BOTH KEEP THE BEST MOISTURE ON THE 925 MB SURFACE JUST TO THE NORTH AND WEST OF THE TAF SITES THROUGH MIDDAY. SO FOR NOW HAVE DECIDED TO JUST MENTION SOME SCATTERED LOW CLOUDS THROUGH THE MORNING AT ALL NORTH/CENTRAL TEXAS TERMINALS BUT WILL HAVE TO WATCH CLOUD TRENDS CLOSELY. OTHERWISE...EXPECT SCATTERED HIGH CLOUDS THIS AFTERNOON AND EVENING. MVFR CEILINGS WILL BE LIKELY BY SUNRISE TUESDAY AS LOW LEVEL MOISTURE SURGES NORTHWARD. A NORTH WIND THIS MORNING WILL TURN TO THE EAST/SOUTHEAST THIS AFTERNOON AND SOUTH TONIGHT. WIND SPEEDS WILL REMAIN BELOW 10 KNOTS THROUGH TONIGHT BUT WILL INCREASE BETWEEN 13 AND 15 KNOTS BY SUNRISE TUESDAY. 79 && .PREV DISCUSSION... /ISSUED 248 AM CST MON JAN 18 2016/ COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY PROGRESSIVE. MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING. IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE... HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID 50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER. SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH. WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR. HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S. A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID TO UPPER 60S AREAWIDE. DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 44 40 61 38 59 / 0 0 5 20 5 WACO, TX 47 41 64 42 63 / 0 0 0 10 5 PARIS, TX 42 35 55 38 56 / 0 0 10 40 5 DENTON, TX 42 38 60 35 57 / 0 0 5 20 5 MCKINNEY, TX 43 37 58 37 57 / 0 0 5 20 5 DALLAS, TX 43 40 61 39 59 / 0 0 5 20 5 TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5 CORSICANA, TX 48 42 61 44 61 / 0 0 5 20 5 TEMPLE, TX 51 41 66 44 64 / 0 0 0 10 5 MINERAL WELLS, TX 44 36 63 34 61 / 0 0 0 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 79/91
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
523 AM CST MON JAN 18 2016 .AVIATION... LIFR TO IFR FOG HAVE PERSISTED AT KLBB AND KPVW RESPECTIVELY. AT KCDS...VFR FOG HAPPENS ON OCCASION. HOWEVER...LIFR TO IFR CIGS WERE OCCURRING AT ALL THREE TAF SITES. EXPECT CONDITIONS TO IMPROVE TO VFR BY LATE MORNING/EARLY AFTERNOON. VFR DECKS WILL RETURN BY THE EVENING-OVERNIGHT. OTHERWISE...LIGHT AND VARIABLE WINDS WILL VEER TO THE SOUTH SOUTHWEST THIS AFTERNOON AT 10-12 KTS...BEFORE DECLINING A BIT SHORTLY AFTER SUNSET. && .PREV DISCUSSION... /ISSUED 214 AM CST MON JAN 18 2016/ SHORT TERM... THE COLD FRONT THAT MOVED IN ACROSS THE SOUTH PLAINS AND ROLLING PLAINS YESTERDAY EVENING...USHERED IN LOW CLOUDS AND AIDED IN THE DEVELOPMENT OF PATCHY AND AREAS /AND AT TIMES LOCALLY DENSE/ FOG. JUST FOR PROSPECTIVE...KLBB REPORTED VIS DOWN TO 5SM DUE TO FOG WHERE AT KPVW IT WAS DOWN TO 3/4SM AT ONE POINT. MOST MODEL SOLUTIONS SUCH AS THE HRRR AND NAM HINT AT DENSE FOG BEING MORE PREVALENT NEAR THE TEXAS AND NEW MEXICO BORDER EARLY THIS MORNING AND SPREADING EASTWARD TO NEAR KLBB BY LATER THIS MORNING. WITH KCVN AND KCVS REPORTING 1/4SM...THE AFOREMENTIONED MODELS COULD HAVE A GOOD HANDLE ON THE SITUATION. WE WILL SEE LATER ON IN THE SHIFT IF A DENSE FREEZING FOG ADVISORY WILL BE REQUIRED. DESPITE THE STRATUS DECK...TEMPS STILL MANAGED TO CRATER INTO THE 20S PER 08Z METARS...WHICH SUGGESTS THIS COLD AIRMASS IS A BIT POTENT. BY MID- LATE MORNING...THE SFC RIDGE RESPONSIBLE FOR DRIVING THE COLD FRONT AND HENCE PROVIDING THE CAA WILL BE GRADUALLY EXITING THE REGION TO THE EAST...WHILST SFC LEE TROUGHING BECOMES ESTABLISHED. THIS WILL LEAD TO SFC WINDS VEERING TO THE S-SW...WHICH IS A WIND COMPONENT FAVORABLE FOR SCOURING OUT LOW CLOUDS AND FOG. MOST AREAS WILL THEREFORE SEE THE SUN BY AT LEAST LATE AFTN. TEMPS TODAY WILL WARM TO AROUND SEASONAL NORMS /50S/ WITH THE EXCEPTION OF THE ROLLING PLAINS /40S/...WHERE CLOUDS WILL BE SLOWEST TO DEPART. AN AMPLIFIED UA RIDGE TO OUR WEST WILL BE TRANSLATING TOWARDS THE REGION TODAY...AND FILTER IN SOME HIGH LEVEL CLOUDINESS BY THIS EVENING- TONIGHT...MAKING FOR A WARMER NIGHT /30S/. LONG TERM... A MILD...DRY...AND PERIODICALLY BREEZY PATTERN SETTING UP THIS WEEK. SPLIT PROGRESSIVE FLOW OVER THE CONUS THIS WEEK WILL BRING A SERIES OF SHORT WAVE TROUGHS ACROSS THE PLAINS...MOST NOTABLY TUESDAY AND AGAIN WEDNESDAY BEFORE LARGER-AMPLITUDE UPPER RIDGING MOVES FROM THE ROCKIES TO THE PLAINS LATE WEEK INTO NEXT WEEKEND. OVERALL...WILL FAVOR THE WARMER END OF MOS GUIDANCE...AS THAT END HAS BEEN SUPERIOR FOR MUCH OF THE LAST SEVERAL MONTHS AND MORE RECENTLY OVER THE LAST WEEK OR SO. PRECIP CHANCES LOOK NEAR NIL. THE BEST CHANCE STILL APPEARS TO BE WEDNESDAY NIGHT...BUT THAT ALSO CONTINUES TO LOOK TO BE EAST OF THE REGION. LOCAL SUPERBLEND INITIALIZATION HAS BROUGHT SLIGHT CHANCE MENTION BACK TO THE ROLLING PLAINS...BUT STILL CONSIDER THAT SCENARIO HIGHLY UNLIKELY AND HAVE KEPT PRECIP MENTION OUT. TEMPS SHOULD BE AT OR ABOVE TO WELL ABOVE CLIMATOLOGY WITH THE EXCEPTION OF THURSDAY WHEN AMPLIFICATION OF THE UPPER FLOW WILL ALLOW SOME COLDER AIR TO SPILL DOWN THE PLAINS. EVEN THEN...TEMPS ARE LIKELY TO ONLY BE A FEW DEGREES OR SO BELOW NORMS. TEMPS REBOUND QUICKLY WITH THE RIDGING MOVING OVERHEAD WITH THE WARMEST DAY OF THE WEEK LOOKING TO BE SATURDAY WITH THE RIDGE AXIS OVERHEAD. && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 29
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
248 AM CST MON JAN 18 2016 .DISCUSSION... COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY PROGRESSIVE. MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING. IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE... HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID 50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER. SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH. WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR. HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S. A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID TO UPPER 60S AREAWIDE. DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK. DUNN && .AVIATION... /ISSUED 1154 PM CST SUN JAN 17 2016/ A COLD FRONT HAS JUST MOVED THROUGH THE METROPLEX TAF SITES AND WINDS HAVE INCREASED TO NEAR 15KT WITH HIGHER GUSTS. THESE WINDS SHOULD DIMINISH SLIGHTLY BUT STILL AVERAGE 10-15KT THROUGH THE NIGHT. THE WINDS WILL GRADUALLY DIMINISH DURING THE DAY MONDAY AND POSSIBLY BECOME NEARLY CALM MONDAY AFTERNOON BEFORE EVENTUALLY RETURNING TO THE SOUTH BY MONDAY EVENING. ONE FORECAST CONCERN IS THE POTENTIAL FOR MVFR CIGS. MOST OF THESE CLOUDS SHOULD REMAIN WEST OF THE TAF SITES BUT SINCE THE FRONTAL INVERSION IS VERY SHARP AND WEAK ISENTROPIC LIFT DOES SET UP BY MORNING...WILL KEEP A MENTION OF SCT017 IN THE TAFS DURING THE MORNING HOURS AS A HEDGE. OUTSIDE OF THIS POSSIBILITY...VFR SHOULD PREVAIL WITH JUST SOME HIGH CLOUDS. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 44 40 61 38 59 / 0 0 5 20 5 WACO, TX 47 41 64 42 63 / 0 0 0 10 5 PARIS, TX 42 35 55 38 56 / 0 0 10 40 5 DENTON, TX 42 38 60 35 57 / 0 0 5 20 5 MCKINNEY, TX 43 37 58 37 57 / 0 0 5 20 5 DALLAS, TX 43 40 61 39 59 / 0 0 5 20 5 TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5 CORSICANA, TX 48 42 61 44 61 / 0 0 5 20 5 TEMPLE, TX 51 41 66 44 64 / 0 0 0 10 5 MINERAL WELLS, TX 44 36 63 34 61 / 0 0 0 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
214 AM CST MON JAN 18 2016 .SHORT TERM... THE COLD FRONT THAT MOVED IN ACROSS THE SOUTH PLAINS AND ROLLING PLAINS YESTERDAY EVENING...USHERED IN LOW CLOUDS AND AIDED IN THE DEVELOPMENT OF PATCHY AND AREAS /AND AT TIMES LOCALLY DENSE/ FOG. JUST FOR PROSPECTIVE...KLBB REPORTED VIS DOWN TO 5SM DUE TO FOG WHERE AT KPVW IT WAS DOWN TO 3/4SM AT ONE POINT. MOST MODEL SOLUTIONS SUCH AS THE HRRR AND NAM HINT AT DENSE FOG BEING MORE PREVALENT NEAR THE TEXAS AND NEW MEXICO BORDER EARLY THIS MORNING AND SPREADING EASTWARD TO NEAR KLBB BY LATER THIS MORNING. WITH KCVN AND KCVS REPORTING 1/4SM...THE AFOREMENTIONED MODELS COULD HAVE A GOOD HANDLE ON THE SITUATION. WE WILL SEE LATER ON IN THE SHIFT IF A DENSE FREEZING FOG ADVISORY WILL BE REQUIRED. DESPITE THE STRATUS DECK...TEMPS STILL MANAGED TO CRATER INTO THE 20S PER 08Z METARS...WHICH SUGGESTS THIS COLD AIRMASS IS A BIT POTENT. BY MID- LATE MORNING...THE SFC RIDGE RESPONSIBLE FOR DRIVING THE COLD FRONT AND HENCE PROVIDING THE CAA WILL BE GRADUALLY EXITING THE REGION TO THE EAST...WHILST SFC LEE TROUGHING BECOMES ESTABLISHED. THIS WILL LEAD TO SFC WINDS VEERING TO THE S-SW...WHICH IS A WIND COMPONENT FAVORABLE FOR SCOURING OUT LOW CLOUDS AND FOG. MOST AREAS WILL THEREFORE SEE THE SUN BY AT LEAST LATE AFTN. TEMPS TODAY WILL WARM TO AROUND SEASONAL NORMS /50S/ WITH THE EXCEPTION OF THE ROLLING PLAINS /40S/...WHERE CLOUDS WILL BE SLOWEST TO DEPART. AN AMPLIFIED UA RIDGE TO OUR WEST WILL BE TRANSLATING TOWARDS THE REGION TODAY...AND FILTER IN SOME HIGH LEVEL CLOUDINESS BY THIS EVENING- TONIGHT...MAKING FOR WARMER NIGHT /30S/. .LONG TERM... A MILD...DRY...AND PERIODICALLY BREEZY PATTERN SETTING UP THIS WEEK. SPLIT PROGRESSIVE FLOW OVER THE CONUS THIS WEEK WILL BRING A SERIES OF SHORT WAVE TROUGHS ACROSS THE PLAINS...MOST NOTABLY TUESDAY AND AGAIN WEDNESDAY BEFORE LARGER-AMPLITUDE UPPER RIDGING MOVES FROM THE ROCKIES TO THE PLAINS LATE WEEK INTO NEXT WEEKEND. OVERALL...WILL FAVOR THE WARMER END OF MOS GUIDANCE...AS THAT END HAS BEEN SUPERIOR FOR MUCH OF THE LAST SEVERAL MONTHS AND MORE RECENTLY OVER THE LAST WEEK OR SO. PRECIP CHANCES LOOK NEAR NIL. THE BEST CHANCE STILL APPEARS TO BE WEDNESDAY NIGHT...BUT THAT ALSO CONTINUES TO LOOK TO BE EAST OF THE REGION. LOCAL SUPERBLEND INITIALIZATION HAS BROUGHT SLIGHT CHANCE MENTION BACK TO THE ROLLING PLAINS...BUT STILL CONSIDER THAT SCENARIO HIGHLY UNLIKELY AND HAVE KEPT PRECIP MENTION OUT. TEMPS SHOULD BE AT OR ABOVE TO WELL ABOVE CLIMATOLOGY WITH THE EXCEPTION OF THURSDAY WHEN AMPLIFICATION OF THE UPPER FLOW WILL ALLOW SOME COLDER AIR TO SPILL DOWN THE PLAINS. EVEN THEN...TEMPS ARE LIKELY TO ONLY BE A FEW DEGREES OR SO BELOW NORMS. TEMPS REBOUND QUICKLY WITH THE RIDGING MOVING OVERHEAD WITH THE WARMEST DAY OF THE WEEK LOOKING TO BE SATURDAY WITH THE RIDGE AXIS OVERHEAD. && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 29/07
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1144 PM CST SUN JAN 17 2016 .AVIATION... POOR FLYING WEATHER EXPECTED OVERNIGHT AND WELL INTO MONDAY MORNING. LIFR CEILINGS AND VISIBILITIES EXPECTED TO PREVAIL THROUGH AROUND 17Z MONDAY. IMPROVEMENT TO VFR EXPECTED TO OCCUR BY EARLY AFTERNOON AS MODERATE SOUTHWEST LOW-LEVEL WINDS ARE MIXED TO THE SURFACE. COCKRELL && .PREV DISCUSSION... /ISSUED 1011 PM CST SUN JAN 17 2016/ UPDATE...PLANT INDUCED SNOW IS PRODUCING ACCUMULATING SNOWFALL NEAR BORGER WHICH FROM LOOKS OF IT ON VIDEO AND FROM REPORTS MAY BE APPROACHING 2" IN SOME AREAS. ISSUED A ONE COUNTY WINTER WEATHER ADVISORY TO HANDLE THIS AS SOME DRIVERS ARE BEING SURPRISED BY SUDDENLY HITTING LOCALIZED SNOWFALL ACCUMULATIONS ON ROADWAYS. WILL BE INTERESTING TO SEE IF PLANTS NE OF AMA ALSO ALSO CAUSE A LOCALIZE BAND LATER TONIGHT. OTHERWISE THE MAIN ISSUE TONIGHT IS FREEZING FOG ACROSS THE AREA. HRRR FINALLY SEEMS TO BE HANDLING THIS POTENTIAL AND THIS COMBINED WITH NARRE SUGGEST THE THREAT WILL MAINLY FOCUS ON THE WRN HALF OF THE PANHANDLE. EXPANDED THE ADVISORY TO INCLUDE ALL WRN TEXAS PANHANDLE COUNTIES. GOOD CHANCE THIS WILL HAVE TO BE EXPANDED TO INCLUDE TEXAS COUNTY IN OK PANHANDLE AS WELL LATE TONIGHT. TEMPTED TO PULL A FEW SE COUNTIES BASED ON HIGH RES MODELS...BUT DECIDED TO LET IT RIDE THERE FOR NOW AS CONFIDENCE IS NOT HIGH ENOUGH TO REMOVE COUNTIES JUST YET. OTHERWISE...JUST INCREASED CLOUD COVER TO SHOW MOST AREAS REMAINING SOLIDLY IN STRATUS AND FOG THROUGH MONDAY MORNING. EXPECT THIS TO BE SLOW TO ERODE...POSSIBLY LASTING MOST OF THE MORNING ON MONDAY. PREV DISCUSSION... /ISSUED 542 PM CST SUN JAN 17 2016/ AVIATION...EXTREMELY SHALLOW ARCTIC AIRMASS HAS PUSHED INTO THE PANHANDLES AND IS LEADING TO VLIFR CONDITIONS WITH LOW CIGS AND EVEN SOME FREEZING FOG IN SOUTHERN AREAS. CURRENT THINKING IS THERE IS NO REASON FOR SIGNIFICANT IMPROVEMENT AS LOW LEVEL WINDS TURN SOUTHERLY OVERNIGHT LIMITING POTENTIAL OF DRIER AIR TO THE NORTH MAKING IT INTO THE AREA. WILL HOLD CIG/VSBY CLOSE TO WHAT CURRENT OBS ARE SHOWING THROUGH MID-LATE MORNING WITH SOME DETERIORATION AT DHT AND GUY AROUND SUNRISE. CERTAINLY SOME UNCERTAINTY IN HOW LOG IFR CONDITIONS WILL LINGER ON MON. PREV DISCUSSION... /ISSUED 335 PM CST SUN JAN 17 2016/ DISCUSSION... AN ARCTIC COLD FRONT WHICH MOVED THROUGH THE PANHANDLES TODAY HAS RESULTED IN STRONG COLD AIR ADVECTION IN ITS WAKE. THE SHALLOW COLD AIR HAS ALSO RESULTED IN CONSIDERABLE LOW CLOUDINESS ALONG WITH PATCHY OR AREAS OF FREEZING FOG ACROSS MUCH OF THE FORECAST AREA. HI- RES MODELS AND LOW-RES MODELS HAVING A DIFFICULT TIME WITH THE FREEZING FOG WHICH MAY BE DUE TO THE SHALLOWNESS OF THE COLD AIR MASS. VISIBILITIES HAVE TANKED TO A HALF MILE OR LESS ACROSS THE CENTRAL AND SOUTH CENTRAL TEXAS PANHANDLE AND ALSO THE SOUTHEAST TEXAS PANHANDLE. HOISTED A FREEZING FOG ADVISORY THIS AFTERNOON THROUGH TONIGHT WHICH EXPIRES AT 16Z MONDAY. FREEZING FOG ADVISORY MAY NEED TO BE EXPANDED IN AREA AND MAY NEED TO BE CANCELLED EARLY SHOULD THE FOG AND LOW CLOUDS LIFT LATER THIS EVENING OR LATE TONIGHT OR BY MONDAY MORNING. TEMPS FALLING INTO THE TEENS AND 20S OVER MOST OF THE AREA AND WENT WITH THE COLDER GUIDANCE FOR MINS TONIGHT. SHALLOW COLD AIR SHOULD BE SHORT-LIVED AS LEE SURFACE TROUGH DEVELOPS WEST OF THE PANHANDLES AND SOUTHWESTERLY SURFACE FLOW PREVAILS BY MONDAY. WARMER AND DRY CONDITIONS EXPECTED MONDAY AND ANOTHER COLD FRONT FORECAST TO PUSH THROUGH THE PANHANDLES TUESDAY. SLIGHTLY COOLER BEHIND THIS FRONT TUESDAY...BUT CONTINUED NEAR OR ABOVE NORMAL TEMPS THROUGH THE MIDDLE OF THE WEEK. MEDIUM RANGE MODELS SEEM TO BACKING OFF SOMEWHAT ON THE WEDNESDAY NIGHT AND THURSDAY UPPER SYSTEM. ECMWF FORECASTING SHORTWAVE TROUGH TRACKING EAST OUT OF THE CENTRAL AND SOUTHERN ROCKIES AND INTO THE PANHANDLES BY 00Z THURSDAY...AND THEN DEVELOPS A CLOSED UPPER LOW OVER THE CENTRAL PLAINS STATES WEDNESDAY NIGHT. THE ECMWF BRINGS A COLD FRONT THROUGH THE FORECAST AREA WEDNESDAY NIGHT. THE GFS FORECASTS CLOSED UPPER LOW MOVING ACROSS THE CENTRAL PLAINS STATES BY 00Z THURSDAY AND THEN DROPS THE CLOSED UPPER LOW SOUTHEAST INTO MISSOURI BY 18Z THURSDAY. THE GFS BRINGS THE COLD FRONT INTO THE FORECAST AREA BY 00Z TO 06Z THURSDAY. BOTH THE GFS AND ECMWF NOW ONLY FORECASTING A BRIEF SHOT OF PRECIP WEDNESDAY NIGHT MAINLY OVER THE NORTHEASTERN SECTIONS OR EASTERN SECTIONS OF THE PANHANDLES. BACKED OFF ON THE POPS AND CONFINED POPS AND SNOW TO THE NORTHEASTERN SECTIONS OF THE FORECAST AREA. WARMER AND DRIER AGAIN FOR LATE THIS WEEK WITH TEMPS BACK UP ABOVE NORMAL. SCHNEIDER && .AMA WATCHES/WARNINGS/ADVISORIES... TX...FREEZING FOG ADVISORY UNTIL 10 AM CST MONDAY FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF SMITH...DONLEY...GRAY...HANSFORD...HARTLEY...HUTCHINSON... MOORE...OLDHAM...POTTER...RANDALL...SHERMAN...WHEELER. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: HUTCHINSON. OK...NONE. && $$ 03/06
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1011 PM CST SUN JAN 17 2016 .UPDATE...PLANT INDUCED SNOW IS PRODUCING ACCUMULATING SNOWFALL NEAR BORGER WHICH FROM LOOKS OF IT ON VIDEO AND FROM REPORTS MAY BE APPROACHING 2" IN SOME AREAS. ISSUED A ONE COUNTY WINTER WEATHER ADVISORY TO HANDLE THIS AS SOME DRIVERS ARE BEING SURPRISED BY SUDDENLY HITTING LOCALIZED SNOWFALL ACCUMULATIONS ON ROADWAYS. WILL BE INTERESTING TO SEE IF PLANTS NE OF AMA ALSO ALSO CAUSE A LOCALIZE BAND LATER TONIGHT. OTHERWISE THE MAIN ISSUE TONIGHT IS FREEZING FOG ACROSS THE AREA. HRRR FINALLY SEEMS TO BE HANDLING THIS POTENTIAL AND THIS COMBINED WITH NARRE SUGGEST THE THREAT WILL MAINLY FOCUS ON THE WRN HALF OF THE PANHANDLE. EXPANDED THE ADVISORY TO INCLUDE ALL WRN TEXAS PANHANDLE COUNTIES. GOOD CHANCE THIS WILL HAVE TO BE EXPANDED TO INCLUDE TEXAS COUNTY IN OK PANHANDLE AS WELL LATE TONIGHT. TEMPTED TO PULL A FEW SE COUNTIES BASED ON HIGH RES MODELS...BUT DECIDED TO LET IT RIDE THERE FOR NOW AS CONFIDENCE IS NOT HIGH ENOUGH TO REMOVE COUNTIES JUST YET. OTHERWISE...JUST INCREASED CLOUD COVER TO SHOW MOST AREAS REMAINING SOLIDLY IN STRATUS AND FOG THROUGH MONDAY MORNING. EXPECT THIS TO BE SLOW TO ERODE...POSSIBLY LASTING MOST OF THE MORNING ON MONDAY. && .PREV DISCUSSION... /ISSUED 542 PM CST SUN JAN 17 2016/ AVIATION...EXTREMELY SHALLOW ARCTIC AIRMASS HAS PUSHED INTO THE PANHANDLES AND IS LEADING TO VLIFR CONDITIONS WITH LOW CIGS AND EVEN SOME FREEZING FOG IN SOUTHERN AREAS. CURRENT THINKING IS THERE IS NO REASON FOR SIGNIFICANT IMPROVEMENT AS LOW LEVEL WINDS TURN SOUTHERLY OVERNIGHT LIMITING POTENTIAL OF DRIER AIR TO THE NORTH MAKING IT INTO THE AREA. WILL HOLD CIG/VSBY CLOSE TO WHAT CURRENT OBS ARE SHOWING THROUGH MID-LATE MORNING WITH SOME DETERIORATION AT DHT AND GUY AROUND SUNRISE. CERTAINLY SOME UNCERTAINTY IN HOW LOG IFR CONDITIONS WILL LINGER ON MON. PREV DISCUSSION... /ISSUED 335 PM CST SUN JAN 17 2016/ DISCUSSION... AN ARCTIC COLD FRONT WHICH MOVED THROUGH THE PANHANDLES TODAY HAS RESULTED IN STRONG COLD AIR ADVECTION IN ITS WAKE. THE SHALLOW COLD AIR HAS ALSO RESULTED IN CONSIDERABLE LOW CLOUDINESS ALONG WITH PATCHY OR AREAS OF FREEZING FOG ACROSS MUCH OF THE FORECAST AREA. HI- RES MODELS AND LOW-RES MODELS HAVING A DIFFICULT TIME WITH THE FREEZING FOG WHICH MAY BE DUE TO THE SHALLOWNESS OF THE COLD AIR MASS. VISIBILITIES HAVE TANKED TO A HALF MILE OR LESS ACROSS THE CENTRAL AND SOUTH CENTRAL TEXAS PANHANDLE AND ALSO THE SOUTHEAST TEXAS PANHANDLE. HOISTED A FREEZING FOG ADVISORY THIS AFTERNOON THROUGH TONIGHT WHICH EXPIRES AT 16Z MONDAY. FREEZING FOG ADVISORY MAY NEED TO BE EXPANDED IN AREA AND MAY NEED TO BE CANCELLED EARLY SHOULD THE FOG AND LOW CLOUDS LIFT LATER THIS EVENING OR LATE TONIGHT OR BY MONDAY MORNING. TEMPS FALLING INTO THE TEENS AND 20S OVER MOST OF THE AREA AND WENT WITH THE COLDER GUIDANCE FOR MINS TONIGHT. SHALLOW COLD AIR SHOULD BE SHORT-LIVED AS LEE SURFACE TROUGH DEVELOPS WEST OF THE PANHANDLES AND SOUTHWESTERLY SURFACE FLOW PREVAILS BY MONDAY. WARMER AND DRY CONDITIONS EXPECTED MONDAY AND ANOTHER COLD FRONT FORECAST TO PUSH THROUGH THE PANHANDLES TUESDAY. SLIGHTLY COOLER BEHIND THIS FRONT TUESDAY...BUT CONTINUED NEAR OR ABOVE NORMAL TEMPS THROUGH THE MIDDLE OF THE WEEK. MEDIUM RANGE MODELS SEEM TO BACKING OFF SOMEWHAT ON THE WEDNESDAY NIGHT AND THURSDAY UPPER SYSTEM. ECMWF FORECASTING SHORTWAVE TROUGH TRACKING EAST OUT OF THE CENTRAL AND SOUTHERN ROCKIES AND INTO THE PANHANDLES BY 00Z THURSDAY...AND THEN DEVELOPS A CLOSED UPPER LOW OVER THE CENTRAL PLAINS STATES WEDNESDAY NIGHT. THE ECMWF BRINGS A COLD FRONT THROUGH THE FORECAST AREA WEDNESDAY NIGHT. THE GFS FORECASTS CLOSED UPPER LOW MOVING ACROSS THE CENTRAL PLAINS STATES BY 00Z THURSDAY AND THEN DROPS THE CLOSED UPPER LOW SOUTHEAST INTO MISSOURI BY 18Z THURSDAY. THE GFS BRINGS THE COLD FRONT INTO THE FORECAST AREA BY 00Z TO 06Z THURSDAY. BOTH THE GFS AND ECMWF NOW ONLY FORECASTING A BRIEF SHOT OF PRECIP WEDNESDAY NIGHT MAINLY OVER THE NORTHEASTERN SECTIONS OR EASTERN SECTIONS OF THE PANHANDLES. BACKED OFF ON THE POPS AND CONFINED POPS AND SNOW TO THE NORTHEASTERN SECTIONS OF THE FORECAST AREA. WARMER AND DRIER AGAIN FOR LATE THIS WEEK WITH TEMPS BACK UP ABOVE NORMAL. SCHNEIDER && .AMA WATCHES/WARNINGS/ADVISORIES... TX...FREEZING FOG ADVISORY UNTIL 10 AM CST MONDAY FOR THE FOLLOWING ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF SMITH...DONLEY...GRAY...HANSFORD...HARTLEY...HUTCHINSON... MOORE...OLDHAM...POTTER...RANDALL...SHERMAN...WHEELER. WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING ZONES: HUTCHINSON. OK...NONE. && $$ MJG
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
423 AM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA THROUGH TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO THE FORECAST AREA. THE HRRR...ARW AND SPC WRF INDICATE PRECIPITATION DIMINISHING AS IT MOVES INTO THE FORECAST AREA FROM THE WEST LATE THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20 PERCENT SOUTH. THE TOP-DOWN METHOD RUN ON BOTH THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND SNOW CLOSE TO THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A RAIN AND SNOW MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED ON THE WET BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE RIDGE. FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA. NO SIGNIFICANT IMPACTS ARE EXPECTED AT THIS TIME BECAUSE OF LIGHT AMOUNTS AND MARGINAL TEMPERATURES. THE GUIDANCE TEMPERATURES ARE LIKELY TOO HIGH TODAY BECAUSE OF A COLD START...CLOUDINESS...AND EVAPORATIVE COOLING POTENTIAL. MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. THE NAM MOS DID INDICATE A SMALL POP IN THE SOUTH PART LATE TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE GFS AND ECMWF INDICATED A LOWER POP. USED AN AVERAGE OF THE GUIDANCE AND FORECASTED A SMALL POP IN THE SOUTH PART. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB TEMPERATURES ABOVE FREEZING IN THE SOUTH PART DURING THE PRECIPITATION CHANCE TIME INDICATED BY THE NAM. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW PRESSURE SYSTEM LIFTS NORTHEAST. MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE 1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS REMAINS A LOW CONFIDENCE FORECAST. WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH MAY HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE ARW AND SPC WRF DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR- SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS AFTERNOON WITH THE AXIS JUST EAST OF THE AREA. USED THE GFS LAMP FOR THE WIND FORECAST. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
308 AM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA THROUGH TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. A WEAK COLD FRONT WILL MOVE INTO THE AREA LATE TONIGHT. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL BE NEAR THE FORECAST AREA FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO THE FORECAST AREA. THE HRRR...ARW AND SPC WRF INDICATE PRECIPITATION DIMINISHING AS IT MOVES INTO THE FORECAST AREA FROM THE WEST LATE THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20 PERCENT SOUTH. THE TOP-DOWN METHOD RUN ON BOTH THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND SNOW CLOSE TO THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A RAIN AND SNOW MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED ON THE WET BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE RIDGE. FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA. NO SIGNIFICANT IMPACTS ARE EXPECTED AT THIS TIME BECAUSE OF LIGHT AMOUNTS AND MARGINAL TEMPERATURES. THE GUIDANCE TEMPERATURES ARE LIKELY TOO HIGH TODAY BECAUSE OF A COLD START...CLOUDINESS...AND EVAPORATIVE COOLING POTENTIAL. MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. THE NAM MOS DID INDICATE A SMALL POP IN THE SOUTH PART LATE TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE GFS AND ECMWF INDICATED A LOWER POP. USED AN AVERAGE OF THE GUIDANCE AND FORECASTED A SMALL POP IN THE SOUTH PART. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB TEMPERATURES ABOVE FREEZING IN THE SOUTH PART DURING THE PRECIPITATION CHANCE TIME INDICATED BY THE NAM. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... THE LOW WILL MARCH EASTWARD WITH A WARM FRONT MOVING INTO THE AREA THURSDAY LATE MORNING WITH INCREASING CHANCES OF RAIN THROUGH THE AFTERNOON. AS THE SYSTEM MOVES INTO THE CENTRAL GULF STATES THURSDAY NIGHT CHANCES OF RAIN WILL CONTINUE INCREASING. THURSDAY NIGHT THERE MAY BE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS THE NORTH AND CENTRAL MIDLANDS. TEMPERATURES MAY BE NEAR FREEZING ACROSS THE NORTHERN MIDLANDS. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE 1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF PRECIP TYPE PROBABILITIES FOR FREEZING RAIN ARE MODERATELY HIGH IN THAT REGION. WILL MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING AT THIS TIME AND LOWER TEMPERATURES FOR THURSDAY/FRIDAY TIME FRAME DUE TO POSSIBLE WEDGE DEVELOPMENT IN THAT REGION. CONFIDENCE REMAINS LOW. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS ARE IN GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. MODELS STILL DIFFER SLIGHTLY WITH THE TRACK OF THIS SYSTEM AND HAVE CONTINUED TO TREND TOWARD A CONSENSUS WITH THE LOW MOVING EASTWARD THROUGH THE DAY FRIDAY AND OFFSHORE OF NC FRIDAY NIGHT. THE SYSTEM WILL THEN TURN NORTHEASTWARD AND MOVE ALONG THE COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH MAY HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE ARW AND SPC WRF DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR- SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS AFTERNOON WITH THE AXIS JUST EAST OF THE AREA. USED THE GFS LAMP FOR THE WIND FORECAST. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
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
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
326 AM EST WED JAN 20 2016 .SYNOPSIS... ISSUED AT 326 AM EST WED JAN 20 2016 LIGHT SNOW WILL OVERSPREAD THE AREA THROUGH DAYBREAK BEFORE ENDING WEST TO EAST MID TO LATE MORNING. SNOW ACCUMULATIONS OF AN INCH OR LESS ARE EXPECTED NORTH OF HIGHWAY 30...WITH ONE TO TWO INCHES SOUTH. HIGHS THIS AFTERNOON WILL RANGE THROUGH THE LOW 20S. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 326 AM EST WED JAN 20 2016 VIGOROUS NRN STREAM SW DROPPING SEWD THROUGH WRN WI ATTM WILL MINOR OUT ACRS THE ERN LAKES TONIGHT. LL MSTR FLUX AHD OF THIS SYS WANES W/NWD EXTENT INTO THE TEETH OF ERODING ARCTIC DOME AND DELAYING TOP DOWN SATURATION TIMED W/STRONGEST MID LVL BASED FORCING. HWVR -SN WILL OVERSPREAD MOST AREAS THROUGH DAYBREAK...ALTHOUGH AMTS XPCD TO REMAIN TRIVIAL OWING TO WANING MID LVL ASCENT AND OVERALL BRIEF DURATION (INCH OR LESS NORTH OF 30 AND 1-2 INCHES SOUTH) AND OF LTL CONCERN IN LIGHT OF GENERAL MID TEEN SFC TEMPS. OTRWS SFC RIDGING TO REDVLP IN WAKE OF THIS SYS OVERNIGHT HWVR CLDS XPCD TO PERSIST UNDERNEATH GROWING SUBSIDENCE INDUCED THERMAL INVERSION. && .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 326 AM EST WED JAN 20 2016 QUIET/SEASONAL WX AND GRADUAL MODERATION ANTICIPATED THURSDAY- SUNDAY...WITH NEXT DECENT OPPORTUNITY FOR PRECIPITATION EARLY NEXT WEEK... PROGRESSIVE FLOW PATTERN WILL PERSIST ALOFT THROUGH THE LONG TERM AS SEVERAL UPPER LEVEL TROUGHS CREST WEST COAST RIDGE INTO DOWNSTREAM/BROAD EASTERN CONUS TROUGH. FIRST DIGGING SHORTWAVE STILL ON TARGET TO CLOSE OFF AND TAKE A MORE SOUTHERLY ROUTE THROUGH THE SOUTHEAST US/MID ATLANTIC FRIDAY INTO SATURDAY. DEFORMATION PRECIP SHIELD ON NORTHERN FRINGE WILL LIKELY PASS SOUTH AND EAST OF THE LOCAL AREA...ALTHOUGH CLOUD CANOPY AND TIGHTENING LOW LEVEL HEIGHT GRADIENT (INCREASING ENE FLOW) WILL STILL MAKE FOR A SOMEWHAT RAW FRIDAY-EARLY SATURDAY. CLOUDS SHOULD SCOUR OUT WITH SOME WARMING INTO SUNDAY AS RIDGING THROUGH THE COLUMN FOLDS IN. THE NEXT UPPER TROUGH AND POTENTIAL FRONTAL WAVE DEVELOPMENT WILL PROVIDE THE NEXT CHANCE FOR SNOW AND RAIN BY EARLY NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1243 AM EST WED JAN 20 2016 UPSTREAM CONDS ACRS NRN IL QUITE TELLING THIS MORNING AND CONFIRM LATEST RAP TIME-HEIGHT CROSS SECTIONS INDICATING A SLOW TOP DOWN SATURATION TAKING PLACE. THUS NO CHOICE BUT TO FOLLOW DAMPENED RAP/HRRR BLEND W/ONSET OF -SN LTR THIS MORNING. BRIEF PD OF MVFR RESTRICTION PSBL TIMED W/FINAL SATURATION/WANING ASCENT OVERLAP YET XPC AN INCH OR LESS AT BOTH TERMINALS. LWR BOUND MVFR CIGS TO PERSIST INTO AFTN BFR IMPROVING AS SFC TROUGH PASSES THROUGH ALG W/INCREASING SUBSIDENCE YIELDING VFR CONDS LT PD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$FISHER SYNOPSIS...T SHORT TERM...T LONG TERM...STEINWEDEL AVIATION...T VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1249 AM EST WED JAN 20 2016 .SYNOPSIS... ISSUED AT 315 PM EST TUE JAN 19 2016 CLOUDS WILL INCREASE LATER THIS EVENING AHEAD OF A WEAK SYSTEM THAT WILL SPREAD LIGHT SNOW ACROSS THE REGION LATE TONIGHT AND WEDNESDAY MORNING. SNOW ACCUMULATIONS SHOULD BE UNDER TWO INCHES WITH MANY LOCATIONS ONLY SEEING AN INCH OR LESS. TEMPERATURES WILL SLOWLY WARM OVER THE NEXT SEVERAL DAYS...HEADING BACK TOWARDS FREEZING BY THE WEEKEND. && .UPDATE... ISSUED AT 826 PM EST TUE JAN 19 2016 MAIN GRID ADJUSTMENT THIS EVE WAS TO LOWER MINS SEVERAL DEGREES ACROSS NWRN PORTION OF CWA WHERE LIGHT WINDS AND FRESH SNOW COVER WERE RESULTING IN A PERIOD OF STRONG RADIATIONAL COOLING. OTRWS SLOWED TIMING OF APCHG SNOW SHIELD SLIGHTLY... BUT ACCUMS STILL LOOK GOOD AND LIGHT SNOW STILL EXPECTED ACROSS MOST IF NOT ALL OF THE CWA DURING THE MORNING COMMUTE TIME WED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 313 PM EST TUE JAN 19 2016 SW FLOW AHEAD OF THE NEXT SYSTEM HAS PUSHED LAKE EFFECT THREAT NORTH OF THE AREA. HIGH CLOUDS WERE STREAMING EASTWARD WITH AN AREA OF LIGHT SNOW EXTENDING FROM NORTHERN IOWA TO WEST OF ST LOUIS. MODELS HAVE TRENDED SOMEWHAT FASTER WITH ARRIVAL OF PRECIP BUT WITH DRY AIRMASS IN PLACE THINK THEY HAVE GOTTEN CARRIED AWAY WITH TIMING (6Z ONSET IN FAR SW). DID A GENERAL AVERAGE OF RUC POPS AND PREVIOUS FORECAST TO TRY TO NUDGE UPWARD WITH ONSET BUT KEEP REASONABLE. CONCERNS WITH REGARDS TO NORTHERN EXTENT OF SNOWFALL AS MAIN FORCING REMAINS US 30 AND SOUTH WITH SFC LOW PASSING WELL SOUTH OF THE AREA. RADAR TRENDS ACROSS N IOWA SEEM TO BE WEAKENING AS WELL LEADING TO INCREASING CONCERN. WITH REGARDS TO QPF/SNOW AMOUNTS...LARGE DENDRITIC GROWTH ZONE WILL ARRIVE AT THE PEAK WITH A DEPTH OF MORE THAN 10,000 FT. THIS DEPTH WILL BE NEEDED TO HELP MAKE UP FOR THE LACK OF SATURATION IN THE SAME LAYER AND ONLY WEAK LIFT. ALL THESE FACTORS LEAD TO A CONTINUATION OF LOW ACCUMULATIONS WITH LESS THAN AN INCH NORTH OF US 30 AND MAYBE UP TO AN INCH AND HALF SOUTH. WOULD NOT BE SURPRISED TO SEE MICHIGAN COUNTIES GET LITTLE MORE THAN A FEW TENTHS OF AN INCH. EVEN WITH THE LIGHT AMOUNTS...THERE MAY BE SOME MORNING TRAVEL ISSUES GIVEN TIMING OF THE EVENT AND TENDENCIES FOR THESE LIGHT EVENTS TO CAUSE MORE HEADACHES THAN SOME OF THE BIGGER ONES. LOOKS LIKE SNOW SHOULD TRANSITION QUICKLY WEST TO EAST...POSSIBLY BEGINNING TO EXIT THE AREA BY 12Z WEDS IN THE FAR WEST AND GONE BY 18Z EAST. HAVE MADE ONLY MINOR CHANGES TO PREVIOUS FORECAST BEYOND 12Z WITH TIMING ISSUES. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 313 PM EST TUE JAN 19 2016 OVERALL A QUIET LONG TERM PERIOD FOR MID JANUARY BUT A COUPLE SYSTEMS TO WATCH. HIGH PRESSURE WILL BE MOVING IN TO START THE PERIOD WEDNESDAY NIGHT. WINDS WILL BECOME LIGHT OR CALM AS ANTICYCLONE CENTER DRIFTS INTO THE AREA OVERNIGHT. WITH CLEARING SKIES AND LIGHT WINDS SHOULD SEE A GOOD RADIATIONAL RESPONSE. HAVE LOWERED TEMPS A FEW DEGREES TOWARDS THE LOWER END OF MOS. WOULD BE TEMPTED TO LOWER FURTHER IF MORE SNOWFALL WAS EXPECTED WEDNESDAY. LIGHT ACCUMS ALONG WITH DEPARTING COLD POCKET AND WARM AIR ADVECTION ALOFT PRECLUDES ANY ADDITIONAL LOWERING AT THIS TIME. NEXT FOCUS IS WITH STRONG CYCLOGENESIS EXPECTED TO TAKE PLACE FROM THE MID SOUTH TO THE ATLANTIC COAST REGION FRIDAY INTO SATURDAY AS SPLIT FLOW PHASES AND ENERGY TRANSFERS TO COASTAL LOW DEVELOPMENT. NORTHERN STREAM SHORT WAVE RESPONSIBLE FOR INFUSING THIS SYSTEM WILL DROP ACROSS OUR AREA FRIDAY. MODELS STILL HAVE DIFFERENCES ON WHERE PERTINENT UPPER AIR FEATURES AND SFC LOW WILL TRACK BUT DEEPENING SYSTEM WILL AID IN INCREASING EAST TO NORTHEAST LOW LEVEL FLOW LOCALLY WHICH IN TANDEM WITH PASSING SHORT WAVE SHOULD HELP PULL COLDER AIR AND MORE CLOUDS INTO THE FORECAST AREA FRIDAY. PCPN CHANCES LOOK SMALL WITH MOISTURE STARVED SHORT WAVE THAT QUICKLY GETS ABSORBED INTO SOUTHERN WAVE SO KEPT FORECAST DRY DESPITE THE INCREASING MID LEVEL MOISTURE AND LOW LEVEL COLD AIR ADVECTION. ONCE SYSTEM WRAPS AND DEEPENS WE WILL SEE SUBSIDENCE WITH INCREASING SHORT WAVE RIDGING WITH CLEARING SKIES AND MODERATING TEMPS FOR SATURDAY. AS WITH PREVIOUS SHIFT DID ALLOW A LOW CHANCE FOR LIGHT SNOW TO CONTINUE IN THE FAR SOUTHEAST WITH ANY NORTHWARD ADJUSTMENT STILL POSSIBLE. NEXT DECENT CHANCE FOR PCPN LOCALLY WILL BE MONDAY OR TUESDAY WITH WHAT APPEARS TO BE A COMPLICATED PARTIALLY PHASED SYSTEM. GFS ON THE FASTER SIDE WHILE 12Z ECMWF SLOWER WITH MORE PCPN TUESDAY. EXPECT ADDITIONAL CHANGES IN MODELS SO FEW CHANGES MADE AND GENERALLY STAYED WITH INHERITED LOW CHANCE POPS FOR THE ENTIRE PERIOD. COULD STILL BE A RAIN OR SNOW EVENT AS WELL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1243 AM EST WED JAN 20 2016 UPSTREAM CONDS ACRS NRN IL QUITE TELLING THIS MORNING AND CONFIRM LATEST RAP TIME-HEIGHT CROSS SECTIONS INDICATING A SLOW TOP DOWN SATURATION TAKING PLACE. THUS NO CHOICE BUT TO FOLLOW DAMPENED RAP/HRRR BLEND W/ONSET OF -SN LTR THIS MORNING. BRIEF PD OF MVFR RESTRICTION PSBL TIMED W/FINAL SATURATION/WANING ASCENT OVERLAP YET XPC AN INCH OR LESS AT BOTH TERMINALS. LWR BOUND MVFR CIGS TO PERSIST INTO AFTN BFR IMPROVING AS SFC TROUGH PASSES THROUGH ALG W/INCREASING SUBSIDENCE YIELDING VFR CONDS LT PD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...JT SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...LASHLEY AVIATION...T VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1138 PM CST TUE JAN 19 2016 ...AVIATION UPDATE... .SYNOPSIS... ISSUED AT 243 PM CST TUE JAN 19 2016 A SHRTWV TROF ADVECTING THROUGH NW FLOW LEAD TO SNOW ACROSS THE IOWA AND N MO THIS AFTERNOON. SNOWFALL TOTALS OF 1 TO 4 INCHES HAVE BEEN REPORTED IN SW IA INTO S CENTRAL IA. THIS FEATURE WILL MOVE TO THE EAST THROUGH THE REST OF TODAY. AS THE COLUMN BEGINS TO SATURATE...SNOW WILL OVERSPREAD THE CWA THIS EVENING. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 243 PM CST TUE JAN 19 2016 MAIN FORECAST CONCERN FOR THE SHORT TERM IS THE SNOW THIS AFTERNOON AND INTO THE EVENING. GUIDANCE AND OBSERVATIONAL TRENDS SUGGESTS THAT HEAVIEST SNOW...4+ INCHES...WILL OCCUR JUST TO THE SOUTH OF THE CWA. AS A RESULT...UPDATED SNOW TOTALS AND CURRENT CHANGES TO THE FORECAST WILL RESULT IN THE ADDITION OF MCDONOUGH COUNTY IN THE WS.Y. THE BEST CHANCE FOR 3+ INCHES WILL BE SOUTH OF A LINE FROM MACOMB TO KEOSAUQUA. HIRES GUIDANCE....SPECIFICALLY THE HRRR AND HIRES NMM KEEPS THE HEAVIEST SNOW TO OUR SOUTH THIS EVENING. THIS LINES UP WITH AN OMEGA SIGNAL IN THE DGZ AS WELL. IT APPEARS THAT LIGHT SNOW WILL OVERSPREAD THE AREA FROM WEST TO EAST. NEAR 00Z...AS THE OMEGA INCREASES ACROSS THE SOUTH...SNOW INTENSITY SHOULD PICK UP. AT THIS TIME...THE VORT WILL BE QUICKLY MOVING THROUGH LEADING TO A QUICK END TO THE SNOW FROM WEST TO EAST. THINK THAT MOST OF THE SNOW WILL BE OVER AOA 06Z WED. A LOOK AT THE FORECAST PLUMES SUGGESTS THAT THE HIGHEST CONFIDENCE FOR 3+ INCHES WILL BE ACROSS OUR EXTREME SOUTH. SNOW TOTALS SHOULD RAPIDLY DECREASE AS YOU MOVE NORTH OF HWY 34 CORRIDOR WITH THE QC SEEING AROUND AN INCH TOTAL. THIS IS SUPPORTED BY THE HIRES GUIDANCE AND ENSEMBLE OUTPUT. PAST THIS..IT LOOKS LIKE SOME OF THE WARMEST TEMPS IN THE PAST COUPLE OF DAYS WILL BE TOMORROW WITH NO CHANCE OF POPS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 243 PM CST TUE JAN 19 2016 QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA WEDNESDAY NIGHT THROUGH THURSDAY AS HIGH PRESSURE QUICKLY MOVES THROUGH THE AREA. TEMPERATURES WILL AVERAGE BELOW NORMAL. ON THURSDAY NIGHT...MAINLY DRY CONDITIONS ARE EXPECTED AS THE HIGH MOVES INTO THE OHIO VALLEY. A WEAK DISTURBANCE MOVING THROUGH THE UPPER MIDWEST MAY BRING SOME FLURRIES OR VERY LIGHT SNOW TO THE HIGHWAY 20 CORRIDOR WEST OF DUBUQUE. DRY CONDITIONS WILL THEN BE SEEN ACROSS THE AREA ON FRIDAY AS ANOTHER HIGH PRESSURE BUILDS INTO THE MIDWEST. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL. FRIDAY NIGHT ON... THE MODEL CONSENSUS HAS DRY CONDITIONS FRIDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE MOVES INTO THE OHIO VALLEY. TEMPERATURES WILL SLOWLY CLIMB TO ABOVE NORMAL ON SUNDAY. ATTENTION THEN TURNS TO A POTENTIAL STORM SYSTEM. SUNDAY NIGHT INTO MONDAY THE MODELS DIVERGE ON THEIR RESPECTIVE SOLUTIONS. THE ECMWF IS DRY BUT THE GEM AND TO A MUCH LESSER EXTENT THE GFS SUGGEST A WEAK STORM SYSTEM MOVING THROUGH THE AREA. GIVEN THE CONSIDERABLE DIFFERENCES...THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS FOR SUNDAY NIGHT AND MONDAY. MONDAY NIGHT AND TUESDAY THE MODEL CONSENSUS HAS DRY CONDITIONS AS HIGH PRESSURE BUILDS INTO THE MIDWEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1134 PM CST TUE JAN 19 2016 LIGHT SNOW WILL END...OR DIMINISH TO NON ACCUMULATING FLURRIES BETWEEN 05Z AND 07Z THIS EVENING. AS THE SNOW ENDS...MVFR CIGS WILL LIFT TO VFR FOR A SHORT PERIOD...BEFORE LIKELY DROPPING TO THE 600 TO 1500 FT RANGE FOR THE EARLY MORNING THROUGH MID MORNING HOURS WEDNESDAY. THIS WILL BE DUE TO SATURATED LOW LEVELS IN THE WAKE OF THE EVENING SNOW EVENT AND PERSISTENT LIGHT SOUTHEAST WIND. I WILL SHOW SOME MODEST IMPROVEMENT DURING THE DAY WEDNESDAY...BUT DO NOT EXPECT WIDESPREAD VFR THROUGH THE PERIOD. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LEE-VAN BUREN. IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR HANCOCK- MCDONOUGH. MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK- SCOTLAND. && $$ SYNOPSIS...GIBBS SHORT TERM...GIBBS LONG TERM...08 AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
239 AM MST WED JAN 20 2016 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 237 AM MST WED JAN 20 2016 LATEST SATELLITE IMAGERY AND UPPER AIR ANALYSIS SHOWS SEMI ZONAL FLOW OVER THE CONUS. A LONG BAND OF CLOUD COVER WAS EVIDENT OVER THE ROCKIES AHEAD OF A SHORT WAVE TROUGH. LOW CLOUDS AND FOG WERE MOVING NORTH OVER THE TRI-STATE AREA DUE TO INCREASED MOISTURE ADVECTION FROM THE LOW LEVEL JET. LATEST OBSERVATIONS SHOW VISIBILITIES UNDER A MILE BEING REPORTED SPORADICALLY UNDER THE LOW CLOUDS. TODAY EXPECT THE FOG AND LOW CLOUDS TO PROGRESS NORTHWARD ACROSS THE ENTIRE AREA. THE WORST OF THE FOG WILL BE EAST OF THE COLORADO BORDER...WITH THE LOWEST VISIBILITIES OCCURRING DURING THE FIRST HALF OF THE MORNING. DUE TO CLOUDS REMAINING OVER THE AREA THROUGH THE DAY...THE FOG MAY LINGER A BIT LONGER THAN NORMAL. LOCATIONS WHERE VISIBILITIES ARE UNDER A MILE WILL LIKELY HAVE A THIN GLAZE OF ICE DEVELOP ON EXPOSED SURFACES. OTHERWISE AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA TODAY. DUE TO THE WEAK LIFT AND MOST OF THE MOISTURE REMAINING ABOVE 700MB...DO NOT ANTICIPATE ANY PRECIPITATION OCCURRING DURING THE DAY. TONIGHT A SECOND UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE AREA...CLOSING OFF FROM THE REST OF THE UPPER LEVEL FLOW OVER THE NORTHEAST HALF OF THE AREA. THE MAJORITY OF THE VORTICITY WILL BE WITH THE FIRST SHORT WAVE TROUGH...AHEAD OF THIS SECOND ONE. THIS WILL LEAD TO LITTLE OR NO MID/UPPER LEVEL LIFT WITH THIS TROUGH AS IT MOVES THROUGH. HOWEVER WEAK LOW LEVEL FRONTOGENESIS...IN THE FIRST KILOMETER ABOVE GROUND WHERE THE ENVIRONMENT WILL BE SATURATED...WILL LEAD TO SOME SNOW DEVELOPING AFTER MIDNIGHT OVER THE NORTHEAST QUADRANT OF THE AREA. THIS AREA OF SNOWFALL WILL GRADUALLY MOVE EAST WITH THE PARENT TROUGH. MEANWHILE ANOTHER AREA OF LIFT/LOW LEVEL FRONTOGENESIS WILL DEVELOP OVER THE NORTHWEST QUADRANT OF THE AREA BEHIND THE CLOSED LOW. THE FRONTOGENESIS IN THIS PART OF THE AREA IS STRONGER THAN TO THE EAST AND THE WEAK LIFT WITH IT IS DEEPER. IN ADDITION THE HIGH-RESOLUTION MODELS ARE INDICATING A BETTER SHOT OF SNOW DEVELOPING THERE THAN OVER THE EAST. WITH THIS IN MIND WILL HAVE THE BETTER CHANCES FOR SNOWFALL OVER THE NORTHWEST PART OF THE AREA. A COLD FRONT WILL ALSO MOVE THROUGH THE AREA WITH THE SECOND UPPER LEVEL TROUGH AND AHEAD OF THE SNOWFALL. BEHIND THE FRONT WINDS WILL INCREASE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 237 AM MST WED JAN 20 2016 THURSDAY MORNING THE LIGHT SNOW WILL CONTINUE OVER BOTH THE NORTHEAST AND NORTHWEST QUADRANTS OF THE AREA...GRADUALLY MOVING EAST THROUGH THE MORNING. BY THE EARLY AFTERNOON THE WEAK LIFT WILL END CAUSING ANY LINGERING SNOW TO END AS WELL. TOTAL SNOWFALL FOR TONIGHT AND THURSDAY WILL BE LESS THAN AN INCH. IN ADDITION TO THE SNOW NORTH WINDS WILL BE WINDY...WITH GUSTS UP TO 40 MPH OVER THE WEST HALF OF THE AREA. TO THE EAST THE WINDS WILL NOT BE AS STRONG DUE TO A WEAKER LOW LEVEL JET OVERHEAD. THE WINDS WILL LEAD TO BLOWING SNOW WHICH MAY REDUCE VISIBILITIES SOME. THE BLOWING SNOW WILL END DURING THE AFTERNOON. BEHIND THE SNOW CLOUDS WILL BEGIN TO CLEAR AS DRIER AIR MOVES INTO THE AREA FROM THE WEST. THURSDAY NIGHT WINDS WILL QUICKLY DECLINE DURING THE EVENING. MEANWHILE CLOUDS WILL CONTINUE TO CLEAR FROM WEST TO EAST. WITH A COOLER AIR MASS IN PLACE TEMPERATURES WILL FALL INTO THE TEENS. THIS WILL LEAD TO WIND CHILLS IN THE SINGLE DIGITS BY SUNRISE. FRIDAY/FRIDAY NIGHT WILL BE UNEVENTFUL AS DRIER AIR REMAINS IN PLACE AS A LONG WAVE RIDGE MOVES OVERHEAD. TEMPERATURES WILL WARM TO NEAR NORMAL. SATURDAY...UPPER RIDGE AXIS MOVES OVER THE AREA DURING THE DAY AHEAD OF A BROAD UPPER TROUGH WHOSE AXIS MOVES ASHORE BY SUNSET. FLOW ALOFT SHIFTS TO THE SOUTHWEST AS A RESULT AND CONTINUES THROUGH THE NIGHT. SOME HIGH CLOUDINESS EXPECTED DURING THE DAY...DECREASING SOME OVERNIGHT. NO PRECIPITATION EXPECTED. AFTERNOON TEMPERATURES PEAK IN THE MID 40S TO MID 50S (EAST TO WEST) WITH OVERNIGHT LOWS IN THE LOW TO MID 20S. SUNDAY...LONG RANGE MODELS IN BETTER AGREEMENT (COMPARED TO 24 HOURS AGO) BRINGING BASE OF UPPER TROUGH INTO THE AREA BY DAYS END THEN INTO THE MIDWEST OVERNIGHT. COLD FRONT MOVES THROUGH AS WELL WITH NORTHERLY SURFACE WINDS. MODELS DISAGREE ON EXTENT OF COLD AIR WITH THE ECMWF SEVERAL DEGREES COLDER AT 850MB WHEN COMPARED TO THE GFS. CURRENT FORECAST HIGHS IN THE MID TO UPPER 40S WOULD FAVOR THE GFS SOLUTION. NORTH WINDS CONTINUE OVERNIGHT WITH LOW TEMPERATURES IN THE LOW TO MID 20S. AS FAR AS PRECIPITATION CHANCES...WILL KEEP SOME SLIGHT CHANCE POPS GOING FOR THE DAY...INCREASING JUST A BIT OVERNIGHT. MONDAY...SUNDAYS WEATHER SYSTEM MOVES AWAY FROM THE AREA BUT THE FORECAST AREA IS CAUGHT IN NORTHWEST FLOW ALOFT ALLOWING MORE WEATHER SYSTEMS TO MOVE INTO THE AREA. CURRENTLY HAVE A DRY FORECAST BUT WOULDNT BE SURPRISED IF WE HAVE SOME SPOTTY LIGHT PRECIP. MAY SEE BREEZY NORTHWEST WINDS DURING THE DAY AS WELL. AFTERNOON TEMPERATURES A BIT COOLER AND JUST BELOW NORMAL WITH UPPER 30S TO LOW 40S. LOOKING AT SOME DECREASING CLOUDINESS OVERNIGHT WITH LOW TEMPERATURES IN THE MID TEENS TO LOW 20S. TUESDAY...SUNSHINE RETURNS TO THE AREA AS HIGH AMPLITUDE RIDGE AXIS MOVES SLOWLY TOWARD THE AREA DURING THE DAY. RIDGE AXIS BREAKS DOWN PRETTY QUICKLY OVERNIGHT WITH SOME INCREASE IN HIGH CLOUDS EXPECTED. AFTERNOON TEMPERATURES WARM BACK INTO THE LOW TO MID 40S WITH OVERNIGHT LOWS AGAIN IN THE MID TEENS TO LOW 20S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1023 PM MST TUE JAN 19 2016 VFR CONDITIONS WILL CONTINUE BRIEFLY AT KGLD AND KMCK AND THEN DETERIORATE TO MVFR AND LOWER, ESPECIALLY AT KMCK. THE HRRR KEEPS KGLD AT VFR WHILE THE NAM BRINGS SOME LOWER CONDITIONS. CONDITIONS SHOULD IMPROVE RATHER EARLY WEDNESDAY MORNING EVEN AT KMCK. SOME MID LEVEL CLOUDS REMAIN IN RESPONSE TO THE NEXT SHORTWAVE THAT COMES THROUGH WEDNESDAY AFTERNOON. CLOUDS DECREASE BRIEFLY WEDNESDAY EVENING IN A BRIEF LULL BEFORE THE NEXT SHORTWAVE AFFECTS THE AREA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...JTL LONG TERM...99/JTL AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1038 PM MST TUE JAN 19 2016 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 210 PM MST TUE JAN 19 2016 EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS RIDGING ACROSS THE ROCKIES WITH A SHORTWAVE TROUGH TRANSITIONING OUT OF THE PLAINS TOWARDS THE CENTRAL MISSISSIPPI RIVER VALLEY. ANOTHER SHORTWAVE TROUGH UPSTREAM OF THE RIDGE IS MOVING INTO THE PACIFIC NORTHWEST WITH A MUCH STRONGER WEST-EAST ORIENTATED UPPER LEVEL JET OVER NORTHERN CALIFORNIA. AT THE SURFACE LEE TROUGH HAS DEVELOPED OVER EAST CENTRAL COLORADO (NEAR FRONT RANGE) AND WARM FRONT IS IN THE PROCESS OF LIFTING OVER THE NORTHEAST PART OF OUR CWA (FROM KMCK TO KHLC). PERSISTENT STRATUS IS STILL IN PLACE IN OUR EASTERN CWA WITH CLOUD SHIELD BREAKING UP IN THE WEST. THIS EVENING-WEDNESDAY MORNING...MAIN CONCERN WILL FOCUS ON POSSIBLE DENSE FOG DEVELOPMENT THIS EVENING/OVERNIGHT. MODELS SUPPORT LEE TROUGH SHIFTING EASTWARD WITH SOUTHERLY FLOW QUICKLY DEVELOPING AFTER SUNSET. THIS SHOULD HELP ADVECT GOOD BL MOISTURE BACK INTO OUR CWA AND STRATUS IN THE EAST COULD THEN EXPAND WESTWARD. EARLIER HRRR/RAP SUPPORTED FOG REDEVELOPING AFTER 00Z THIS EVENING NEAR THE CO/KS BORDER AND SPREADING EASTWARD. LATEST SREF/NAM/RAP/HRRR NOW SHOWING STRONGER SIGNAL AFTER MIDNIGHT TONIGHT THROUGH EARLY WEDNESDAY MORNING WITH MAIN FOG AXIS SHIFTED FURTHER EAST (TOWARD BACK EDGE OF CURRENT STRATUS DECK). I KEPT FOG COVERAGE/TIMING SIMILAR TO EARLY GUIDANCE COVER POSSIBILITY...HOWEVER CONFIDENCE AT THIS POINT IS SIGNIFICANTLY LOWER ON WHERE OR IF DENSE FOG MAY DEVELOP OVER OUR CWA. (FOG MAY BE A GOOD BET BUT DENSE FOG MAY BE PATCHY). WEDNESDAY...TWO SHORTWAVES ARE EXPECTED TO MOVE ACROSS THE ROCKIES AND OVER OUR CWA WITH THE FIRST (WEAKER) SHORTWAVE MOVING OVER OUR CWA MIDDAY WEDNESDAY. AS WAS INDICATED IN EARLIER GUIDANCE ON MID SHIFT THERE IS A SIGNIFICANT DRY LAYER FROM ABOVE THE BL TO 600- 700MB. DESPITE FORCING THIS LOWERS CONFIDENCE IN ANY MEASURABLE PRECIP DURING THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON THE SECOND (STRONGER) SHORTWAVE TROUGH DIGS SOUTHEAST AND OVERTAKES THE FIRST TROUGH WITH A STRONGER UPPER LEVEL JET BEGINNING TO DEVELOP. BY LATE AFTERNOON THERE IS A WEAK PRECIP SIGNAL IN OUR FAR EASTERN CWA AND GUIDANCE THERE DOES SHOW SOME MOISTENING OF THE MOISTURE PROFILE. I KEPT SMALL AREA OF SLIGHT CHANCE POPS IN GRAHAM/NORTON COUNTIES TO MATCH THIS...BUT CONFIDENCE IS STILL NOT HIGH THAT THINGS WOULD START THIS EARLY. OTHER CONCERN FOR WEDNESDAY WILL BE HIGHS. POTENTIAL EXISTS AGAIN FOR LINGERING STRATUS...HOWEVER WITH TROUGHS MOVING THROUGH THE REGION THICK/OPAQUE MID-HIGH CLOUD COVER COULD ALSO LIMIT DIURNAL HEATING. I LOWERED HIGHS IN THE EAST FROM PREVIOUS FORECAST DUE TO POTENTIAL IMPACTS OF CLOUD COVER. TOUGH CALL AND IF WE WERE TO CLEAR OUT (MORE LIKELY IN THE WEST) WE COULD SEE HIGHS IN THE UPPER 40S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 248 PM MST TUE JAN 19 2016 FORECAST ISSUES WILL BE CHANCE OF PRECIPITATION AND PHASE OF PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY. SATELLITE SHOWING A SOMEWHAT AMPLIFIED BUT STILL PROGRESSIVE AND ACTIVE FLOW PATTERN FROM THE PACIFIC INTO THE WESTERN ATLANTIC. LARGE AND COMPLICATED UPPER TROUGH IS OVER THE NORTHEAST PACIFIC. AT JET LEVEL...THE MODELS WERE HAVING A LITTLE TROUBLE WITH THE JET ALONG THE WEST COAST. AT MID LEVELS...MODELS WERE ALL ABOUT THE SAME BUT THEY WERE ALSO A LITTLE FAR EAST/FAST WITH THE UPPER TROUGH NOW COMING ON THE COAST. THE NAM/ECMWF WAS DOING THE BEST ON THE SURFACE WIND AND PRESSURE FIELD. THE GFS AND CANADIAN WERE DOING THE BEST ON THE LOW LEVEL THERMAL FIELD WITH MOST MODELS NOT BEING COLD ENOUGH. WEDNESDAY NIGHT...DEVELOPING PRECIPITATION EVENT IS IN ITS BEGINNING STAGES. MODELS DIFFERENT ON SPEED...POSITION AND AMPLITUDE OF MID LEVEL CIRCULATION THAT APPEARS TO BE DEVELOPING ON TOP OF US OR JUST TO THE EAST OF US. TODAYS MODEL RUNS VERY DIFFERENT THAN 24 HOURS AGO. BY THE BEGINNING OF THIS PERIOD...MODELS STILL HAVE STRONG NORTH TO SOUTH JET ON THE WEST SIDE OF THIS UPPER SYSTEM. THIS COMBINED WITH THE PROBLEM OF THE MODELS INITIALLY HAVING THIS SYSTEM TOO FAR EAST THIS MORNING...LEADS ME TO BELIEVE THAT WHATEVER ENDS UP BEING THE SLOWER AND EVEN FURTHER SOUTH SOLUTION WILL END UP BEING MORE RIGHT. EVEN NOW AM THINKING CURRENT MODEL RUN STILL MAY BE TOO FAST/FAR NORTH. TROUGH IS ELONGATED AND COMPROMISED OF A NORTHERN AND SOUTHERN CIRCULATIONS WITHIN THIS TROUGH. PAST EXPERIENCE HAS SHOWN THIS SETUP IS NOT GREAT FOR A LOT OF PRECIPITATION. SAYING ALL THAT...THE FAR EASTERN PORTION OF THE AREA WILL HAVE THE BEST CHANCE WITH BEST CHANCE OVERALL AT THIS TIME BEING TO THE EAST OF OUR AREA. THE GRADIENT OF THE CHANCE OF PRECIPITATION WILL BE REALLY SHARP. PER THE REASONING ABOVE...AM THINKING THAT THE BEST CHANCE OF PRECIPITATION WILL BE AFTER MIDNIGHT AND THAT IS SUPPORTED BY THE SREF PROBABILITIES. BEST CHANCE WILL BE VERY LATE IN THE NIGHT. THERE IS NOT A LOT OF COLD AIR WITH THIS SYSTEM...AND DEPENDING ON WHICH MODEL YOU CHOOSE THE CHANGE OVER MAY NOT OCCUR UNTIL LATE EVENING/AROUND MIDNIGHT WITH THE EASTERN AREAS CHANGING OVER FIRST. THE PHASE IS REALLY WHERE THERE ARE BIG DIFFERENCES. SOME MODELS KEEPING TOTALLY DRY OR HAVE JUST ENOUGH MOISTURE IN THE LOW LEVELS FOR DRIZZLE/FREEZING DRIZZLE. SO A LOT OF UNCERTAINTY WITH THIS SYSTEM. THURSDAY/THURSDAY NIGHT...WITH THE PROXIMITY OF THE SYSTEM AND EXPECTED SLOWNESS...ALONG WITH MID AND UPPER LEVEL LIFT EXPECTED...EXPECT THE BEST CHANCE OF PRECIPITATION WILL BE IN THE MORNING AND THEN RAPIDLY DECREASE AND END. IF CURRENT FORECAST PANS OUT...THE FAR EASTERN PORTION OF THE AREA GETS 1 TO 2 INCHES. GRADIENT AND DOWNWARD MOTION BEHIND THE SYSTEM WILL CREATE BREEZY TO WINDY CONDITIONS. THE STRONGEST WINDS ARE AFTER THE SNOW ENDS...AND WITH TEMPERATURES JUST ABOVE FREEZING...DO NOT EXPECT ANY BLOWING SNOW PROBLEMS AT THIS TIME. CURRENT HIGH TEMPERATURE FORECAST LOOKS TO BE IN GOOD SHAPE AND MADE ONLY MINOR ADJUSTMENTS. HOWEVER...IF MORE SNOW THAN EXPECT IT WILL BE COLDER. LIGHT WINDS AND LITTLE CLOUD COVER WILL ALLOW OVERNIGHT TEMPERATURES TO DROP A DECENT AMOUNT. FRIDAY...STRONG MID/UPPER LEVEL RIDGE BUILDS IN OVER THE AREA. SURFACE WILL MOVE THROUGH AND TO THE EAST OF THE AREA DURING THE DAY. SO DO EXPECT RECYCLED COOL AIR. THE EASTERN LOCATIONS WILL BE THE COLDEST AND OVERALL REDUCED THE HIGH TEMPERATURES A LITTLE. FRIDAY NIGHT THROUGH TUESDAY...MID AND UPPER RIDGE WILL BE IN PLACE FROM FRIDAY NIGHT INTO SATURDAY NIGHT SO EXPECT MODERATING TEMPERATURES AND DRY CONDITIONS. THE INIT WAS REASONABLE WITH THIS AND MADE NO CHANGES. A STRONG SHORTWAVE TROUGH...NOT UNLIKE THE ONE THAT WENT THROUGH THIS MORNING AND SIMILAR ALSO THE SYSTEM EXPECTED WEDNESDAY NIGHT AND THURSDAY...WILL MOVE THROUGH SUNDAY AND SUNDAY NIGHT. THE INIT PRODUCED SLIGHT CHANCE POPS DURING THIS PERIOD AND SEEMS REASONABLE. POSSIBLE THAT THESE CHANCES WILL INCREASE. AFTER THAT RIDGING WILL MOVE INTO THE AREA AND BRING DRY CONDITIONS AND MODERATING TEMPERATURES ONCE AGAIN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1023 PM MST TUE JAN 19 2016 VFR CONDITIONS WILL CONTINUE BRIEFLY AT KGLD AND KMCK AND THEN DETERIORATE TO MVFR AND LOWER, ESPECIALLY AT KMCK. THE HRRR KEEPS KGLD AT VFR WHILE THE NAM BRINGS SOME LOWER CONDITIONS. CONDITIONS SHOULD IMPROVE RATHER EARLY WEDNESDAY MORNING EVEN AT KMCK. SOME MID LEVEL CLOUDS REMAIN IN RESPONSE TO THE NEXT SHORTWAVE THAT COMES THROUGH WEDNESDAY AFTERNOON. CLOUDS DECREASE BRIEFLY WEDNESDAY EVENING IN A BRIEF LULL BEFORE THE NEXT SHORTWAVE AFFECTS THE AREA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...FS
AREA FORECAST DISCUSSION
NWS JACKSON KY
222 AM EST WED JAN 20 2016 .UPDATE... ISSUED AT 222 AM EST WED JAN 20 2016 SNOW JUST NOW BEGINNING ITS PUSH INTO CENTRAL KENTUCKY...WITH PERHAPS SOME FLURRIES MAKING INTO THE CUMBERLAND PLATEAU. HAVE SLOWED DOWN THE ONSET OF PRECIPITATION A BIT FOR A FEW MORE HOURS. LOOKS LIKE AFTER 4 AM...WE SHOULD START TO SEE BETTER COVERAGE. A LITTLE CONCERNED THE DRY AIR AND SOUTHEAST DOWNSLOPING FLOW CURRENTLY IN PLACE MAY LIMIT THE INITIAL PUSH OF PRECIPITATION INTO EASTERN KENTUCKY. THIS COMBINED WITH WHAT MODELS ARE PORTRAYING AS SNOW RATIOS POSSIBLY UNDER 10 IN THE SOUTH MAY LIMIT OVERALL SNOWFALL POTENTIAL. HAVE CHOPPED DOWN SNOWFALL TOTALS A BIT TO MORE IN THE 1 TO 2 INCH RANGE GIVEN THE SOMEWHAT UNFAVORABLE CONDITIONS AT THE ONSET. THE OTHER THING TO CONSIDER IS THE BEST OMEGA STILL DOESN`T COINCIDE WITH THE DENDRITIC GROWTH ZONE...WHICH IS PROBABLY WHY THE SNOW RATIOS ARE COMING IN LOWER. REGARDLESS...WE SHOULD STILL BE CLOSE TO ADVISORY CRITERIA ON THE SNOWFALL...BUT IT WILL BE A CHALLENGE TO REACH THE 4 INCHES FOR A WARNING IN WAYNE COUNTY. REGARDLESS...BEING WE WILL GET CLOSE...AND TO AVOID CONFUSION...WILL LEAVE HEADLINES UNCHANGED. UPDATE ISSUED AT 1040 PM EST TUE JAN 19 2016 THE LEADING EDGE OF PRECIPITATION FROM A SYSTEM TO AFFECT THE REGION LATER TONIGHT AND INTO WEDNESDAY NIGHT HAS MOVED INTO SOUTHERN IL AND FAR WESTERN KY. THIS PRECIPITATION SHOULD CONTINUE TO SPREAD EAST OVERNIGHT AND INTO WEDNESDAY MORNING. THE 18Z NAM AND NOW THE 0Z NAM HAVE POINTED TOWARD HIGHER QPF IN THE FAR SW COMPARED TO THE PREVIOUS FORECAST. THE 0Z GFS ALSO HAS QPF THAT SHOULD BE ENTIRELY OR ALMOST ENTIRELY SNOW OF AROUND 0.40 INCHES IN WAYNE COUNTY. WITH SNOW RATIOS EXPECTED TO BE 10 TO 11 TO 1 THAT WOULD PROBABLY PUSH WAYNE COUNTY TO AT OR SLIGHTLY ABOVE THE 12 HOUR WINTER STORM WARNING CRITERIA OF 4 INCHES. WITH THIS IN MIND...WAYNE COUNTY HAS BEEN UPGRADED TO A WINTER STORM WARNING FOR 3 TO 5 INCHES OF SNOW. NEIGHBORING COUNTIES TO WANE SHOULD PICK UP AMOUNTS IN THE 2 TO 4 INCH RANGE...WITH AMOUNTS TAPERING OFF FROM THERE TO THE NORTH AND EAST DUE TO DRIER AIR IN PLACE. SOME OF THE RECENT RAP AND HRRR RUNS SUPPORT THE 0Z NAM AND 0Z GFS TO AN EXTENT ALTHOUGH THE 2Z RAP HAS HIGHER QPF FURTHER NORTH INTO THE PULASKI TO LAUREL COUNTY CORRIDOR. THE MOST RECENT HRRR IS SLIGHTLY LIGHTER WITH AM SNOW IN THE SW COUNTIES COMPARED TO A COUPLE OF EARLIER RUNS...SO OVERALL SOME UNCERTAINTY REMAINS EVEN WITH THIS SYSTEM. HOWEVER...THERE SEEMS TO BE AN UPWARD TREND IN QPF AND SNOWFALL FOR THE FAR SW THUS THE WAYNE COUNTY UPGRADE. AN UPDATED WSW AND HWO HAVE BEEN ISSUED. AS FOR THE LATE WEEK SYSTEM...THE DISTURBANCES THAT SHOULD INTERACT OR PHASE TOGETHER FOR THE EASTERN CONUS TROUGH AND LOW PRESSURE SYSTEM ARE NOW ONSHORE OF THE WESTERN U.S. OR MOVING ONSHORE AT THIS TIME. AS UPPER AIR NETWORKS BEGIN TO CAPTURE THE STRENGTH OF THESE SYSTEMS...MODEL RUNS FROM 0Z THIS MORNING AND INTO WEDNESDAY SHOULD BEGIN TO CLOSE IN WITH MORE OF A CONSENSUS. THIS SYSTEM WILL CONTINUE TO BE MONITORED AND IS ALSO BEING HIGHLIGHTED IN WEATHER STORIES AND HWO. UPDATE ISSUED AT 810 PM EST TUE JAN 19 2016 OTHER THAN FINE TUNING THE HOURLY TEMPERATURE FORECAST FOR THE NEXT FEW HOURS...NO CHANGES ARE NEEDED AT THIS TIME. AS THE 0Z MODEL RUNS COME IN AS WELL AS THE 21Z SREF AND HRRR AND RAP RUNS WILL BE EVALUATED FOR WHETHER OR NOT QPF AND SNOW AMOUNTS MAY NEED TO INCREASED ACROSS THE LAKE CUMBERLAND REGION. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 406 PM EST TUE JAN 19 2016 CURRENT CONDITIONS ACROSS THE AREA FEATURE CLOUD COVER ON THE INCREASE IN WESTERN KENTUCKY ASSOCIATED WITH A DEVELOPING SYSTEM. MEANWHILE...IN EASTERN KENTUCKY CLOUD COVER IS DISSIPATING AS NORTHWEST UPSLOPE FLOW DECREASES AS THE CENTER OF THE ARCTIC HIGH HAS MOVED OVER THE AREA. THUS HAVE CLEARED SKY COVER AND SHUT OFF THE FLURRIES ACROSS THE AREA AS WELL. AFTER 00Z TONIGHT...SKIES WILL CLOUD UP AGAIN AS THE NEXT SYSTEM MOVES THROUGH THE BLUEGRASS. PRECIP WILL BEGIN TO MOVE INTO THE AREA AFTER 08Z. MODEL TRENDS HAVE KEPT THIS FEATURE WITH A GOOD AMOUNT OF LIFT AND MOISTURE. TRENDS HAVE ALSO TAKEN THE MOST AMOUNT OF MOISTURE TO THE SOUTH INTO CENTRAL KY AND THEN INTO TN JUST CLIPPING WETS OF THE I-75 CORRIDOR. THIS REGION WILL LIKELY SEE THE MOST AMOUNT OF SNOW FROM THIS FEATURE. SURFACE TEMPS AS THIS FEATURE MOVES IN WILL JUST BE RECOVERING FROM THE ARCTIC AIR MASS THAT HAS JUST EVACUATED THE AREA. THUS PRECIP WILL BEGIN AS SNOW FOR THIS SYSTEM. WARMEST TEMPS THOUGH WILL BE IN THE SOUTH WITH SOUTHERLY FLOW SETTING UP AHEAD OF THE FRONT. THUS...SNOW RATIOS WILL BE SLIGHTLY LOWER THAN THE NORTH AS THIS FEATURE MOVES INTO THE AREA. SNOW WILL CONTINUE ACROSS EASTERN KENTUCKY THROUGH THE DAY AND BECOME MODERATE TO EVEN HEAVY AT TIMES. HIGH RATIOS TO THE NORTH WILL MAKE FOR SNOWFALL AMOUNTS IN THE 1 TO 2 INCH RANGE BUT MORE MOISTURE IN THE SOUTH WILL MAKE FOR 2 TO 3+ AMOUNTS DESPITE THE LOWER SNOW RATIOS. THE OTHER CONCERN FOR SNOW AMOUNTS WITH THIS FEATURE WILL BE THE PROGRESSIVE FLOW AS THIS SYSTEM MOVES THROUGH. AS THE SYSTEM LOSES A BIT OF MOISTURE MOVING INTO THE AREA...THE DEPTH OF THE MOISTURE LESSENS QUITE QUICKLY BY WEDNESDAY AFTERNOON AND INTO WEDNESDAY NIGHT. DUE TO THIS MUCH OF THE SNOW WILL CHANGE OVER TO FREEZING DRIZZLE HEADING INTO WEDNESDAY EVENING AND WEDNESDAY NIGHT. IN FACT...A GLAZE OF ICE IS POSSIBLE IN SOME AREAS...ESPECIALLY IN THE SOUTH...WHERE UP TO 0.05 HUNDREDTHS ARE POSSIBLE. THIS SET UP MAY ALSO TAKE AWAY FROM SOME OF THE SNOWFALL POTENTIAL IN THE SOUTH. THUS...WILL KEEP THE WINTER WEATHER ADVISORY OUT FOR THE ENTIRE AREA FROM TOMORROW MORNING AND THROUGH THURSDAY NIGHT. HEADING INTO WEDNESDAY NIGHT...THE SYSTEM EXITS THE AREA AS THE LAST OF THE LOW LEVEL MOISTURE EXITS AS WELL. THIS WILL BRING AN END TO THE FREEZING DRIZZLE THREAT BEFORE THE NEXT FEATURE BEGINS TO IMPACT THE AREA MOVING IN FROM THE SOUTH. IN FACT...WE WILL HAVE A BRIEF BREAK IN THE PRECIP BY THURSDAY MORNING. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 406 PM EST TUE JAN 19 2016 COMPLICATED FORECAST IN THE LONG TERM WITH LOTS OF ATTENTION ON A POSSIBLE MAJOR WINTER STORM IN THE THURSDAY NIGHT THROUGH SATURDAY TIME RANGE. AS OUR MIDWEEK WINTER SYSTEM PASSES TO OUR EAST...TEMPERATURES ALOFT WILL BE ON THE RISE AS A WARM FRONT AT THE SURFACE MOVES UP THE GREAT VALLEY OF EAST TENNESSEE VALLEY. THIS WILL SEND PRECIPITATION BACK NORTH INTO THE AREA LATE THURSDAY INTO THURSDAY NIGHT. THERMAL PROFILE IS TRICKY BUT P-TYPE IS EXPECTED TO BE MOSTLY RAIN ACROSS THE SOUTH BUT A MIX OF RAIN...SNOW AND FREEZING RAIN ALONG AND NORTH OF THE HAL ROGERS PARKWAY THURSDAY NIGHT...AND PROBABLY ALL SNOW OR A MIX OF FREEZING RAIN AND SNOW FROM I-64 NORTH. FORECAST MODELS THEN DIVERGE INTO FRIDAY BUT THE PRESENCE OF AN INVERTED TROUGH EXTENDING UP THE GREAT VALLEY OF EAST TENNESSEE INTO THE CUMBERLAND VALLEY WOULD SUPPORT A SCENARIO WHERE THE WARM NOSE ALOFT EDGES FURTHER NORTH CAUSING PRECIP TO MIX WITH OR CHANGE TO RAIN PERHAPS AS FAR NORTH AS THE MOUNTAIN PARKWAY AND POSSIBLY EVEN I-64. THE NORTHWARD EXTEND TO THE CHANGE TO RAIN DEPENDS GREATLY ON THE STRENGTH AND TRACK OF THE SURFACE LOW...WITH WHICH THERE IS JUST A LOT OF UNCERTAINTY DUE TO MODEL DIFFERENCES SO TRIED TO PAINT WITH A BROAD BRUSH AS FAR AS THE ACTUAL P-TYPE FORECAST GOES RIGHT NOW THROUGH THE DAY FRIDAY. SO...WHILE THE ACTUAL WEATHER YOU WILL SEE REMAINS UNCERTAIN THURSDAY NIGHT AND FRIDAY...PLAN TO BE IMPACTED BY THE WEATHER IN SOME FORM OR FASHION IF YOU HAVE TRAVEL PLANS AND MONITOR FORECASTS AS OUR CONFIDENCE IN THE DETAILS IMPROVES OVER THE NEXT DAY OR SO. MODELS ARE FAIRLY CONSISTENT THAT COLDER AIR WILL WRAP IN BEHIND THE DEPARTING SURFACE LOW FRIDAY EVENING CHANGING ALL PRECIP TO SNOW QUICKLY FROM NORTHWEST TO SOUTHEAST. THE SNOW WILL LIKELY CONTINUE THROUGH AT LEAST SATURDAY MORNING...AND POSSIBLY EVEN INTO SATURDAY NIGHT AS THE UPPER LOW IS SLOW TO PIVOT THROUGH. THE POTENTIAL EXISTS FOR SEVERAL INCHES OF SNOW. THE REMAINDER OF THE EXTENDED WILL FEATURE WARMING TEMPS... ALTHOUGH POTENTIAL SNOW COVER WILL HAVE A YET TO BE DETERMINED INFLUENCE THERE. ANOTHER SYSTEM IS PROGGED TO DEVELOP OVER THE SOUTHERN PLAINS AND THEN MOVE NORTHEAST SPREADING ANOTHER CHANCE FOR PRECIPITATION ACROSS THE AREA AS EARLY AS MONDAY. THIS SHOULD BE RAIN AS IT APPEARS RIGHT NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 222 AM EST WED JAN 20 2016 VFR WILL CONTINUE FOR THE NEXT 2 TO 4 HOURS. BY LATE TONIGHT...A WEATHER DISTURBANCE WILL BRING SNOWFALL TO THE FAR SOUTHWEST BY 09Z...SPREADING ACROSS THE ENTIRE AREA BY 16Z. THIS WILL THEN RESULT IN DETERIORATION INTO MVFR AND THEN IFR AND POSSIBLY NEAR OR BELOW AIRPORT MINS AT TIMES FOR VIS IN THE FALLING SNOW AND AND CIGS DURING SNOW AND AFTER IT DEPARTS AND TAPERS TO DRIZZLE OR FREEZING DRIZZLE. WINDS WILL BE LIGHT TO NEAR CALM THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 7 AM EST THURSDAY FOR KYZ052-060-088-104-106>110-112-113-115-117>120. WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR KYZ044-050- 051-058-059-068-069-079-080-084>087-111-114-116. WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR KYZ083. && $$ UPDATE...KAS SHORT TERM...SHALLENBERGER LONG TERM...ABE AVIATION...KAS
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
1118 PM CST TUE JAN 19 2016 .UPDATE... Issued at 642 PM CST TUE JAN 19 2016 Watching very closely the precipitation across SEMO, where light freezing rain/drizzle has been reported and has caused very dangerous travel conditions. Issued a SPS, and highlighted it more strongly in the social media realm. May take a look at the WSW. Thing is, as the upper system moves closer and precip increases, precip loading, top down cooling will start to erode the "warm" layer, or at least suppress it toward the MO/AR border, and transition precip to mainly sleet and snow early this evening. So for now, will handle this as a very short term event, and not complicate the overall message. Will make some minor changes to the grid forecast in this area. The RAP thermal depictions support this approach. CN && .SHORT TERM...(This evening through Wednesday night) Issued at 131 PM CST TUE JAN 19 2016 With 12z model suite painting low end 4 tenths qpf, and high end 6 tenths, and ratios low end 12 to 1, and high end 17 to 1, per collab with WPC and adjacent WFO`s...have upgraded to warn all areas for broad 3 to 5 inch expectation. More specifically, some heavier snow could paint a swath of locally higher amounts (depending upon the solution)... and higher liquid to snow ratios in cold low to mid 20s air... could potentially yield a 6+ inch swath. The main threat area for this is roughly latitudinally along the Ohio river thru the heart of the FA and southward toward the AR/TN borders. On the flip side, if more scant amounts of qpf across our north occur (visa vi the GFS), and using a less gracious LSR, we could see lesser 2 to 2.5" totals along the I-64 corridor from Mount Vernon IL into southwest IN. In summary, broad 3 to 5 inch totals expected snow/sleet. Some chance slightly lower 2 inch totals possible north, and higher 6+ inch totals a possibility across south-central ptns. Cant rule out some hundredths of freezing rain across mainly srn border counties, but focusing mostly on snow/sleet potential given consistency of colder/further southern/eastern track. Factors at play for a little more sleet vs snow include 3 to 6K foot depth of warm nose ranging from -1C to +2C for at times 3 to 6 hrs of pcpn time period. This skews totals a little toward lower end of aforementioned ratios, if it plays out. Adjusted start time of WSW to 00z, given accumulating snows could be ongoing at 03z for farthest western portions of SEMO/SWIL. End time maintained at 18Z, but effectively ends at 15Z for all but farthest southeastern counties...as pcpn shuts off sharply northwest to southeast thru the morning hours Wednesday. .LONG TERM...(Thursday through Tuesday) Issued at 255 PM CST TUE JAN 19 2016 Another messy round of winter weather will follow our mid week event. Models are in good agreement showing a low pressure system centered over central Mississippi at 00z Friday. Being on the cold side of the low along with the expected snow pack across our region, a majority of the precipitation Thursday into Friday will be freezing or frozen. Precipitation is expected to start as a mix of freezing rain, sleet and snow across all but our north and northwest counties, where precipitation should begin as snow and remain snow through the event. Models imply temperatures briefly reaching 33 to 37 degrees across most areas by Thursday afternoon, which would switch us to rain. However confidence is a bit low on how much warming we can get, so kept most areas as a mix except for a portion of west Kentucky and southeast Missouri. For Thursday night, any areas that begin as a mix will switch to all snow by midnight as the low moves off to our southeast overnight. The snow will continue into Friday, tapering off from west to east Friday afternoon into Friday night. Right now 1 to 3 inches of snow is possible, but amounts are questionable at this point and will greatly depend on how warm our surface temperatures can get. The weekend will be dry as high pressures moves across the Gulf of Mexico. Temperatures will reach the middle 30s Saturday, and around 40 degrees Sunday. Another round of precipitation will return for Monday. Models take a surface low right over the PAH forecast area late Monday into Monday night. Rain is possible Monday, then as the low moves overhead and east of us, rain will mix with and change over to snow Monday night. Rain or snow will then be possible for Tuesday into Tuesday night, but we will have to continue to watch the track of the low to see just how warm or cold we will be for the beginning of the work week. && .AVIATION... Issued at 1118 PM CST TUE JAN 19 2016 Trends across Southern Illinois and into Southeast Missouri finally closing in on lower visibilities and ceilings with increased snowfall. May still be 1-2 hours fast at KPAH and KOWB, but model guidance still suggesting a sharp increase in snowfall after midnight, lowering ceilings and visibilities through daybreak. Made slight timing changes for lower ceilings at KCGI and KPAH, but continued downward trend toward IFR conditions between 06-12z Wednesday. && .PAH Watches/Warnings/Advisories... IL...Winter Storm Warning until noon CST Wednesday for ILZ075>078- 080>094. MO...Winter Storm Warning until noon CST Wednesday for MOZ076-086-087- 100-107>112-114. IN...Winter Storm Warning until noon CST Wednesday for INZ081-082- 085>088. KY...Winter Storm Warning until noon CST Wednesday for KYZ001>022. && $$ AVIATION...Smith
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1137 PM CST TUE JAN 19 2016 .AVIATION... SCATTERED SHOWERS WILL ACCOMPANY AN EASTWARD MOVING COLD FRONT DURING THE OVERNIGHT HOURS. SOUTHEAST WINDS AROUND 5 TO 10 KNOTS AHEAD OF THE FRONT TO BECOME NORTHWEST BEHIND THE FRONT. CEILINGS TO BECOME IFR AROUND DAYBREAK ACROSS AREA TERMINALS WITH LITTLE IMPROVEMENT THROUGH 20/18Z. OTHERWISE...VFR CONDITIONS TO PREVAIL THROUGH 21/00Z WITH MVFR/IFR CEILINGS POSSIBLE THEREAFTER. /05/ && .PREV DISCUSSION... /ISSUED 959 PM CST TUE JAN 19 2016/ DISCUSSION... A LINE OF BROKEN CONVECTION HAS DEVELOPED OVER THE LAST COUPLE OF HRS JUST AHEAD OF A COLD FRONT THAT IS ENTERING THE NWRN ZONES. 00Z KSHV RAOB SHOWS A PRONOUNCED DRY LAYER BETWEEN 850-560 MB...INDICATIVE OF SHOW MID LVL DRY SLOTTING IN THE WAKE OF A DEPARTING SHORTWAVE TROUGH PER LATEST WV LOOPS. SOME ADDITIONAL MID/UPPER LVL MOISTURE MOVING INTO THE SRN PLAINS COULD HELP THE ATMOSPHERE MOISTEN FROM THE TOP DOWN IF IT ARRIVES BEFORE THE FRONT. OTHERWISE...PRECIP WILL REMAIN SPOTTY AND SCATTERED AT BEST. RAIN CHANCES MIGHT BE A BIT HIGHER ACROSS SRN AR DURING THE EARLY MORNING HRS AS VERTICAL ASCENT MIGHT BE SLIGHTLY HIGHER DUE TO THE PROXIMITY OF A SFC LOW AND THE UPPER TROUGH AXIS. QUITE A FEW CHANGES WERE MADE IN THE GRIDS DURING THE FIRST 72 HRS OF THE FCST BASED ON THE LATEST HRRR AND THE 00Z NAM. BIGGEST CHANGES WERE MADE TO POPS AND TEMPS. UPDATED PRODUCTS WILL BE SENT SHORTLY. /09/ PREV DISCUSSION... /ISSUED 540 PM CST TUE JAN 19 2016/ AVIATION... CONDITIONS TO DETERIORATE OVERNIGHT AS A COLD FRONT MOVES ACROSS THE AREA. CEILINGS TO BECOME MVFR AHEAD OF THE FRONT FOLLOWED BY AN INCREASE IN COVERAGE OF RAIN SHOWERS AFTER 20/06Z. WINDS TO BECOME NORTHWEST 5 TO 10 KNOTS BEHIND THE FRONT ACROSS MOST AREAS BY DAYBREAK. OTHERWISE...IFR CEILINGS AND VISIBILITIES BETWEEN 20/12Z-20/16Z TO GRADUALLY IMPROVE THROUGHOUT THE DAY. /05/ && .PRELIMINARY POINT TEMPS/POPS... SHV 47 56 50 62 / 40 20 40 50 MLU 48 57 49 65 / 30 40 40 70 DEQ 39 49 40 53 / 40 10 50 60 TXK 41 50 45 56 / 50 10 50 60 ELD 43 52 44 58 / 50 40 50 70 TYR 41 53 49 60 / 40 10 40 40 GGG 43 54 50 61 / 40 10 40 50 LFK 47 59 54 65 / 30 20 30 40 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 05/05/05
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1203 AM EST WED JAN 20 2016 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 354 PM EST TUE JAN 19 2016 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SHRTWV RDG STRETCHING FM NW ONTARIO IN MN WITHIN NW FLOW ALF ON WRN FLANK OF DEPARTING UPR LO OVER SE CANADA. ASSOCIATED SFC HI PRES RDG STRETCHES FM NW ONTARIO THRU THE UPR MS RIVER VALLEY AND TOWARD THE OH RIVER VALLEY. NW FLOW OF COLD AIR...WITH H925 TEMPS ARND -15C OVER THE UPR LKS...IN ADVANCE OF THIS SLOWLY APRCHG RDG IS STILL CAUSING SOME LES...BUT BANDS ARE WEAKER/MORE DISORGANIZED WITH STRONG SUBSIDENCE ASSOCIATED WITH THE APRCHG RDG LOWERING INVRN BASE TOWARD 3-4K FT AGL PER MQT VWP. LLVL WINDS ARE BEGINNING TO BACK AS WELL AHEAD OF THE APRCHG SFC RDG...SO BANDS ARE SHIFTING/LIMITING RESIDENCE TIME. PLENTY OF LO CLDS LINGER UNDER THE LOWERING INVRN DESPITE DRY NATURE OF THE NEAR SFC LYR UPSTREAM /WHERE SFC DEWPTS ARE AOB -20F OVER MUCH OF NRN MN...BUT SOME BREAKS ARE BEGINNING TO SHOW UP OVER THE FAR W NEAR IWD CLOSER TO THE INCOMING SFC HI PRES/ DRY LLVL AIR AND OVER THE SCENTRL WHERE NW FLOW IS DOWNSLOPING. THERE IS ANOTHER SHRTWV STRETCHING FM SASKATCHEWAN INTO THE NRN PLAINS THAT IS DIGGING SEWD...AND SOME HI/MID CLDS AHEAD OF THIS DISTURBANCE ARE SPREADING INTO MN. MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON LINGERING LES TRENDS/ LO CLDS AND IMPACT ON TEMPS. TNGT...SFC HI PRES RDG AXIS IS FCST TO SHIFT SLOWLY TO THE E AND STRETCH FM THE UPR OH VALLEY INTO UPR MI AT 12Z WED. AS THE LLVL WINDS CONTINUE TO BACK TOWARD THE WSW...ANY LINGERING SN SHOWERS OVER THE NRN KEWEENAW AND NEAR LK SUP E OF GRAND MARAIS SHOULD LIFT OUT INTO LK SUP. SINCE THE WINDS WL SHIFT OFFSHORE AND THE INVRN BASE WL LOWER WITH MORE ACYC LLVL FLOW...EXPECT THE BULK OF THE LO CLDS TO SHIFT OVER THE LK AS WELL. ALTHOUGH THE SETUP SEEMS FAVORABLE FOR VERY LO TEMPS WITH LGT OFFSHORE WINDS...MID/HI CLDS ON THE NRN FRINGES OF SHRTWV DIGGING TO THE SE ARE FCST TO MOVE OVER THE CWA AND LIMIT THE DIURNAL TEMP FALL. SO ALTHOUGH THERE MAY BE SOME SUB ZERO MIN TEMPS OVER THE INTERIOR...WIDESPREAD MIN TEMPS UNDER -10F AS OBSVD THIS MRNG OVER NRN MN ARE NOT LIKELY. WED...LARGE SCALE QVECTOR DVGC AHEAD OF SHRTWV RDG AND UNDER SFC RDG AXIS WL MAINTAIN MAINLY DRY WX FOR MOST OF THE CWA...WITH ANY SN SHOWERS OVER LK SUP NEAR LK INDUCED TROF FCST TO LINGER OVER THE N HALF OF THE LK. DURING THE DAY...MANY OF THE MODELS SHOW SOME MSTR RETURN OVER MAINLY THE WRN CWA IN THE SW FLOW BTWN THE SFC RDG SHIFTING SLOWLY TO THE E AND A SHRTWV APRCHG LATE IN THE DAY FM THE NW. BUT SINCE ANY FORCING AND LLVL MSTR INFLOW WL BE MINIMAL...OPTED TO RETAIN ONLY SCHC POPS OVER THE WRN CWA WHERE THE MOISTENING IS FCST TO BE A BIT MORE ROBUST. EXPECT A SOMEWHAT WARMER AFTN WITH H85 TEMPS REBOUNDING TO ARND -12C BY 00Z THU. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 446 PM EST TUE JAN 19 2016 BY 00Z THURSDAY THE SFC HIGH WILL HAVE SLIPPED TO IL-OH...WITH A WEAK RIDGE/LAKE INDUCED LOW SLOWLY DEEPENING ACROSS LAKE SUPERIOR AS THE RIDGE EXITS. THE NEXT IN A SERIES OF SHORTWAVES WILL ASSIST IN THE LIGHT SNOW SHOWER POTENTIAL WEDNESDAY NIGHT...TRACKING FROM SW ONTARIO AT 00Z TO FAR N LAKE HURON BY DAYBREAK THURSDAY. THE MAIN IMPACT WILL BE TO INCREASE NW FLOW ACROSS THE KEWEENAW PENINSULA BEHIND THE WEAK SFC-500MB TROUGH AND ENHANCING LIGHT SNOW SHOWERS THERE. 850MB TEMPS WILL BE AROUND -11C. NOT EXPECTING ADVISORY SNOW AMOUNTS AT THIS TIME. THE NEXT SFC HIGH SITUATED OVER MANITOBA AND N DAKOTA THURSDAY WILL PUSH ACROSS MN AND W LAKE SUPERIOR ON FRIDAY...BUT WILL ONLY SLOWLY BREAK DOWN THE LINGERING WEAK TROUGH OVER E LAKE SUPERIOR/E UPPER MI BY FRIDAY NIGHT. SFC WINDS WILL SHIFT OUT OF THE N THURSDAY NIGHT THROUGH FRIDAY AND 850MB TEMPS WILL FALL TO -12 TO -14C...BUT WITH LIMITED MOISTURE...EXPECT SNOWFALL LESS THAN 2IN. ANOTHER DRY PERIOD IS EXPECTED FRIDAY NIGHT THROUGH SATURDAY NIGHT AS ANOTHER AREA OF HIGH PRESSURE SHIFTS ACROSS THE REGION. BY SATURDAY MORNING ...THE NEXT LOW WILL BET SET UP ACROSS S CENTRAL CANADA WHILE MUCH OF THE ATTENTION WILL BE ON THE TRACK AND TIMING OF THE LOW OFF THE MID ATLANTIC COAST. UPPER MI WILL REMAIN IN BETWEEN SYSTEMS UNTIL THE CANADIAN LOW SHIFTS ACROSS ONTARIO SUNDAY AND THE EASTERN LOW MOVES OFF THE NEW ENGLAND STATES. THE TROUGH LOOKS TO CROSS UPPER MI LATE SUNDAY NIGHT/MONDAY MORNING. THE GFS AND ECMWF ARE OVER 12HRS ON TIMING WHEN THE NEXT SWATH OF SNOW WILL CROSS UPPER MI SUNDAY AFTERNOON-MONDAY...WITH DIFFERENCES IN THE TIMING OF THE NEXT LONGWAVE TROUGH MOVING ACROSS THE CENTRAL PLAINS AND GREAT LAKES STATES. MODERATE TO HIGH CONFIDENCE EXISTS IN THE ONGOING FORECAST FOR UPPER MI UNTIL SUNDAY. OTHERWISE THE CONSENSUS FOR MONDAY-TUESDAY WOULD BE FOR AT LEAST SOME COOLER WITH 850MB TEMPS FALLING AGAIN TO -10 TO -12C. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1203 AM EST WED JAN 20 2016 VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT SAW. LAKE EFFECT MVFR DECK AT CMX WILL GO AWAY WITH SW WINDS KEEPING THEM OFFSHORE...THEN MVFR CONDITIONS RETURN BY LATE WED EVENING. AT IWD...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE PERIOD. THERE WILL BE TIMES WHEN HIGH END MVFR DECK COMES INTO IWD WED MORNING AND AGAIN WED AFTERNOON. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 354 PM EST TUE JAN 19 2016 WITH A RELATIVELY WEAK PRES GRADIENT EXPECTED OVER THE UPPER LAKES MOST OF THIS COMING FORECAST PERIOD...WINDS WILL REMAIN UNDER 25 KTS MOST OF THE TIME. THE BEST CHANCE FOR SW WINDS UP TO 30 KTS WILL BE ON SAT...WHEN A SHARPER GRADIENT BETWEEN HI PRES STRETCHING FROM NEW ENGLAND INTO THE MID MS RIVER VALLEY AND A LO PRES TROF APPROACHING FROM THE NW MAY SUPPORT THE STRONGER WINDS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...07 MARINE...KC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1145 PM CST TUE JAN 19 2016 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 336 PM CST TUE JAN 19 2016 MAIN CONCERN IS FOG POTENTIAL TONIGHT. GENERAL SYNOPTIC PATTERN IS QUITE PROGRESSIVE AS WE TRANSITION TO A HIGHER AMPLITUDE SCENARIO. TONIGHT...THE CONCERN GOES TO FOG POTENTIAL TONIGHT AS WIND WILL BE LIGHT FROM THE SOUTH. THE HRRR IS HITTING THE FOG POTENTIAL A LITTLE HARD CENTRAL AND WEST. THE SREF IS ALSO HITTING FOG A LITTLE HARD EVERYWHERE ACROSS THE CWA...ESPECIALLY WEST. I WENT WITH STRONG WORDING IN THE FORECAST TO AREAS RATHER THAN PATCHY AND EXTENDED THE FOG MENTION FARTHER EAST THAN THE PREVIOUS FORECAST. WE MAY SEE A LITTLE SUN WEDNESDAY MORNING BEFORE IT CLOUDS BACK UP IN ADVANCE OF THE NEXT WAVE QUICKLY APPROACHING. WARM AIR ADVECTION SHOULD BOOST TEMPERATURES A GOOD 10 DEGREES WARMER ON WEDNESDAY COMPARED TO TODAY. NOT EXPECTING PRECIP UNTIL PERHAPS BETWEEN 21Z AND 00Z THURSDAY IN OUR FAR SOUTH...WHERE RAIN/SNOW COULD OCCUR...BUT THE BETTER CHANCES WILL LIKELY BE TOWARD WEDNESDAY NIGHT...IN THE LONG TERM FORECAST. SUPERBLEND TEMPERATURES LOOKED REASONABLE...WHICH LOWERED TEMPERATURES A BIT FOR WEDNESDAY HIGHS COMPARED TO THE PREVIOUS FORECAST. THIS SEEMS REASONABLE CONSIDERING LINGERING FOG POTENTIAL AND INCREASING SKY COVER BY AFTERNOON. BCONSRAW AND NAM12 SOLUTIONS INDICATE THAT IT MIGHT EVEN BE A BIT COOLER THAN THE MID 30S I HAVE ADVERTISED IN THE FORECAST....WITH COOLER TEMPERATURES EAST AND WARMER WEST. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 336 PM CST TUE JAN 19 2016 ALOFT: VERY LITTLE CHANGE IN THE PATTERN IS ENVISIONED FOR AT LEAST THE NEXT WEEK. A MEAN TROF WILL REMAIN OVER THE E PAC WITH THE MEAN RIDGE OVER WRN N AMERICA. THE FLOW WILL INITIALLY BE MODERATELY AMPLIFIED BUT WILL DEAMPLIFY TEMPORARILY AS A TROF MOWS DOWN THE RIDGE FRI-SAT AND EMERGES INTO THE PLAINS SUN-MON. NW FLOW WILL FOLLOW TUE. AT 00Z/THU A SHORTWAVE TROF WILL BE MOVING IN AND AMPLIFYING...WITH A MID-LVL CIRCULATION CLOSING OFF OVER NEB/KS BY 06Z. THIS LOW WILL DROP SSE THU WITH QUIETER WX TO FOLLOW. SURFACE: A WEAK COLD FRONT WILL MOVE THRU WED NIGHT. LEE CYCLOGENESIS WILL BE UNDERWAY WED EVE WITH THE SFC LOW FAR TO THE S OVER TX. CANADIAN HIGH PRES WILL GRADUALLY BUILD IN THU-FRI. RETURN FLOW DEVELOPS SAT AS A CLIPPER HEADS E ACROSS SRN CANADA. A NICE DOWNSLOPE-WARMED AIR MASS WILL OVERTAKE THE REGION...BUT SNOW ON THE GROUND WILL TEMPER THE WARM-UP. THE NEXT PAC COOL FRONT WILL BE MAKING ITS WAY THRU THE WRN USA AND WILL ARRIVE HERE LATE SUN. HIGH PRES WILL MOVE IN MON AND DROP INTO THE SRN PLAINS TUE. SOME DAILY DETAILS... WED NIGHT: SNOW WILL BE BLOSSOMING OVER N-CNTRL KS AND EXPANDING N INTO S-CNTRL NEB. THU: A SWATH OF SNOW WILL PROBABLY STILL ENCOMPASS MUCH OF THE FCST AREA THRU THE MORNING...RESULTING IN PERIODS OF SNOW. IT WILL DIMINISH AND END IN THE AFTERNOON. CURRENT EXPECTATION IS THAT MOST IF NOT ALL THE ACCUMULATING SNOW WILL FALL WED NIGHT. WHILE SNOW WILL CONT INTO THU THE LIFT WILL NOT BE ENOUGH TO RESULT IN MUCH ACCUM. SNOW RATIOS: THIS IS TOUGH BECAUSE THE MESOSCALE NATURE OF THIS SYSTEM WILL RESULT IN HIGHLY NON-UNIFORM LIFT. HIGHER UPWARD VERTICAL MOTION (UVM) WILL RESULT IN HIGHER RATIOS WITHIN THE BAND. GIVEN THAT THE BAND SHOULD BE TRANSIENT...KEPT RATIOS IN THE 10-12 RANGE. BASED ON NAM SOUNDINGS...UVM WILL BE FAIRLY GOOD BELOW THE DGZ FROM I-80 SOUTH. WITH TEMPS WARMER THAN -5C...THIS WILL RESULT IN SUBSTANTIAL RIMING AND RATIOS CLOSE TO 10:1...IE A WETTER SNOW. N OF I-80...IF THE NAM IS CORRECT UVM WILL BE WEAK RESULTING IN LESSER QUALITY/SMALLER FLAKES. THAT TOO SUPPORTS A LOWER RATIO OF 10 OR LESS. ACCUMS: THESE RATIOS OFFER 1-2" AND THAT IS THE OFFICIAL FCST AT THIS POINT...WITH 3-4" POSSIBLE IN A SMALLER AREA WHERE THE BAND IS MORE PERSISTENT. WE JUST DON`T KNOW WHERE THAT WILL OCCUR. SNOW ALGORITHMS FROM THE 06Z/12Z 20KM GFS AND 12Z/18Z NAM OFFER 2-4" ACROSS MUCH OF THE FCST AREA...WITH ISOLATED 6" AMTS POSSIBLE. THE EC CONTS TO BE ON THE HEAVY SIDE OF THE GUIDANCE DISTRIBUTION CONSISTENTLY DUMPING ABOUT .50" SOMEWHERE NEAR ROOKS/OSBORNE/ MITCHELL COUNTIES. THAT INCLUDES THE LAST 4 RUNS. HOWEVER...THE 12Z EC ENSEMBLE MEAN PROBABILITY FOR .50" IN 24 HRS 10% OR LESS. SO THAT CONSTRAINS ME FROM GETTING OVERLY EXCITED. WINDS WILL NOT BE A FACTOR WITH THIS EVENT. FRI: DECREASING CLOUDS AS SUBSIDENT NW FLOW MOVES IN. HIGH TEMPS PROBABLY COLDER THAN NORMAL. SAT: TEMPS AT LEAST NORMAL IF NOT ABOVE. SNOW ON THE GROUND IS A HUGE MITIGATING FACTOR. OTHERWISE...WIDESPREAD HIGHS IN THE 40S AND 50S WOULD BE ON THE TABLE. SUN-MON: INCREASING CLOUDS. COOLER. POSSIBLY A TOUGH OF LIGHT PRECIP AS THE FRONT/TROF MOVE IN. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1135 PM CST TUE JAN 19 2016 PRIMARY FORECAST CONCERN REVOLVES AROUND FOG AND STRATUS POTENTIAL...ESPECIALLY THROUGH THE MORNING HOURS. WIDE SWATH OF MVFR CEILINGS CONTINUES TO AFFECT BOTH TERMINAL AREAS...THOUGH THEY ARE ON THE WRN FRINGES OF THE CLOUD COVER. CONFIDENCE IN THE TIMING OF ANY IMPROVEMENTS OF CEILINGS DUE TO MOVEMENT OF THE STRATUS IS NOT HIGH...AS EVEN JUST A FEW HOURS OUT...MODELS/GUIDANCE CONTINUE TO SHOW NOTABLE DIFFERENCES. AS FAR AS WINDS GO...NO SIGNIFICANT CHANGES EXPECTED THROUGH THE PERIOD...REMAINING S/SERLY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HEINLEIN LONG TERM...HALBLAUB AVIATION...ADP
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1122 PM CST TUE JAN 19 2016 .SYNOPSIS... ISSUED AT 325 PM CST TUE JAN 19 2016 H5 ANALYSIS THIS MORNING HAD A SHORTWAVE TROUGH EXTENDING FROM THE DAKOTAS INTO WESTERN NEBRASKA AND SRN COLORADO. UPSTREAM OF THE TROUGH...A LOW AMPLITUDE RIDGE EXTENDED FROM SWRN UTAH...NWD INTO SRN ALBERTA. WEST OF THE RIDGE...A SHORTWAVE TROUGH WAS PRESENT OFF THE COAST WASHINGTON STATE...OREGON AND NORTHERN CALIFORNIA. CURRENT WV IMAGERY...HAS THE SHORTWAVE EXTENDING FROM EASTERN SOUTH DAKOTA...INTO SOUTH CENTRAL NEBRASKA. FURTHER WEST...A BROAD PLUME OF PACIFIC MOISTURE WAS NOTED AND EXTENDED FROM CALIFORNIA...EWD INTO THE INTER MOUNTAIN WEST. A SECONDARY FEED OF MOISTURE EXTENDED FROM BAJA CALIFORNIA INTO TEXAS AND THE OZARKS. AT THE SURFACE...LIGHT SNOW IN ASSOCIATION WITH THE SHORTWAVE TROUGH...HAD EXITED THE FORECAST AREA BY LATE MORNING. SNOW AMOUNTS WERE ON THE ORDER OF 1 TO 2 INCHES ACROSS THE EASTERN HALF OF THE FORECAST AREA...WITH SOME LOCALLY HEAVIER AMOUNTS UP TO 3 INCHES IN CUSTER COUNTY. SEE OMAPNSLBF FOR DETAILS. SKIES WERE GENERALLY CLOUDY THIS AFTERNOON WITH THE EXCEPTION OF LOCATIONS ALONG AND WEST OF HIGHWAY 61 FROM MERRIMAN TO IMPERIAL. TEMPERATURES THIS AFTERNOON WERE GENERALLY IN THE 20S TO LOWER 30S. && .UPDATE... ISSUED AT 908 PM CST TUE JAN 19 2016 BINGO...DENSE FOG HAS FROMED ACROSS NRN NEB. THE RAP MODEL SHOWS THIS FOG MOVING EAST OVERNIGHT AND LASTING 3 TO 6 HOURS. IT IS POSSIBLE IT COULD FORM FARTHER SOUTH ACCORDING TO THIS MODEL BUT THAT REMAINS UNCERTAIN AT THIS TIME. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 325 PM CST TUE JAN 19 2016 CLEARING CONTINUES TO SPREAD FROM WEST TO EAST ACROSS THE AREA THIS EVENING. HOWEVER THE DRY AIR ALOFT AND GOOD RADIATIONAL COOLING WILL QUICKLY COOL THE SFC TO THE DEW POINT. BOTH THE SHREF AND NAM ARE SUGGESTING SOME FOG TO DEVELOP...AND WITH THE MELTING OF SOME OF THE LIGHT SNOW FROM THIS MORNING ADDING TO THE BL MOISTURE AND NEAR CALM WINDS...GROWING CONFIDENCE THIS COULD DEVELOP. UNSURE ON HOW DENSE IT WILL GET SO NO HEADLINE BUT WILL NEED TO MONITOR THIS CLOSELY. LOWS WILL BE MILD FOR MID JANUARY IN THE TEENS TO AROUND 20. TOMORROW THE FOG WILL SLOWLY ERODE AS THE NEXT WAVE EJECTS ONTO THE PLAINS. MOISTURE IS ON THE INCREASE...HOWEVER A DRY MID LEVEL WILL HAVE TO BE OVERCOME BEFORE ANYTHING REACHES THE GROUND...THUS EXPECT THE DAYTIME TO BE DRY. WEAK RIDGING AHEAD OF THE WAVE WILL PUSH SOME WARM AIR BRIEFLY INTO THE REGION WHICH SHOULD HELP PUSH EARLY HIGHS INTO THE MID 30S TO LOWER 40S...WARMEST WERE LITTLE TO NO SNOW PACK. IF CLOUDS THICKEN QUICKLY...HIGHS COULD BE TO OPTIMISTIC. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 325 PM CST TUE JAN 19 2016 MID RANGE...WEDNESDAY NIGHT THROUGH FRIDAY...THE MAIN FORECAST CHALLENGE IN THE MID RANGE IS SNOWFALL POTENTIAL WITH A SHORTWAVE SYSTEM PROGGED TO CROSS THE CENTRAL AND SRN PLAINS WEDS NIGHT INTO THURSDAY. BEGINNING LATE WEDNESDAY AFTERNOON...WITH THE APPROACH OF AN UPPER LEVEL JET STREAK...A SHORTWAVE TROUGH...WILL DEEPEN AS IT TRACKS FROM WYOMING INTO KANSAS. LIFT WILL BEGIN TO INCREASE OVERNIGHT WEDNESDAY NIGHT...NORTH OF THE SHORTWAVE...WHICH CLOSES OFF AT BOTH THE H7 AND H5 LEVELS AFTER 06Z THURSDAY. CROSS SECTIONS TAKEN ACROSS THE EASTERN CWA INDICATE PLENTY OF DENDRITIC ZONE MOISTURE...ALONG WITH A 12 HR PERIOD (06Z-18Z THURSDAY) OF FAVORABLE LIFT. THIS AREA OF LIFT IS COLLOCATED WITH AN INVERTED SURFACE TROUGH OF LOW PRESSURE WHICH IS PRESENT ACROSS THE EASTERN CWA...OR MAINLY ALONG THE HIGHWAY 183 CORRIDOR FROM ANSLEY TO SPRINGVIEW. SREF QPF/S AS WELL AS THE OPERATIONAL GFS AND NAM SOLNS INDICATE 10 TO 20 HUNDREDTHS OF AN INCH ALONG THIS CORRIDOR...WHICH BASED ON COBB RATIOS OF 12 TO 1...YIELDS 1 TO 2 INCHES OF SNOW IN THE EASTERN HALF OF THE CWA. BASED ON THE CROSS SECTIONS...THIS WILL BE A FAIRLY LONG (12 HRS)...LIGHT INTENSITY EVENT. ATTM FEEL FAIRLY CONFIDENT IN QPF/S AND ACCUMS...HOWEVER...LAYER PWATS IN THE NAM SOLN ARE RUNNING A QUARTER TO BRIEFLY A HALF AN INCH DURING THE PERIOD AND THIS IS CONCERNING. IF THIS VERIFIES...WE COULD BE LOOKING AT MORE SNOW ACCUMS THAN CURRENT THINKING. WILL CONTINUE TO MONITOR THIS WITH THE NEXT COUPLE OF FCST CYCLES. PROGRESSING INTO THURSDAY AFTERNOON...THE UPPER LEVEL LOW WILL TRACK SOUTHEAST INTO THE OZARKS...AS A RIDGE BEGINS TO BUILD INTO THE INTER MOUNTAIN WEST. LIFT WILL BEGIN TO WEAKEN QUICKLY BY THURSDAY AFTERNOON IN THE EAST...WHILE HIGH PRESSURE BUILDS SOUTH FROM THE EASTERN DAKOTAS. SUBSIDENCE AND DRIER AIR...WILL BRING THE THREAT FOR SNOW TO AN END DURING THE AFTERNOON HOURS. ON THURSDAY NIGHT...HIGH PRESSURE WILL BUILD SOUTH INTO EASTERN NEBRASKA. LOW TEMPERATURES WERE TRENDED DOWNWARD IN THE EAST GIVEN ITS PROXIMITY TO THE TRACK OF THE HIGH WITH GUIDANCE UNDERCUT 2 TO 5 DEGREES. HIGH PRESSURE WILL TRANSITION EAST INTO MINNESOTA AND NORTHERN IOWA BY FRIDAY AFTERNOON. WARMER AIR WILL BEGIN TO PUSH INTO WESTERN NEBRASKA BY AFTERNOON...WITH H85 TEMPS REACHING ABOVE 0C WEST OF HIGHWAY 61. WINDS...ESPECIALLY EAST OF HIGHWAY 61 WILL BE LIGHT...SO NOT MUCH MIXING WILL TAKE PLACE. THIS WILL RESULT IN SUB FREEZING HIGHS GENERALLY EAST OF HIGHWAY 83...WHILE LOCATIONS WEST OF THIS ROUTE MAY REACH THE MID 30S TO LOWER 40S IN THE EASTERN PANHANDLE. LONG RANGE...FRIDAY NIGHT THROUGH TUESDAY...BEGINNING FRIDAY NIGHT...RIDGING WILL BUILD EAST OF THE ROCKIES ONTO THE CENTRAL PLAINS. MUCH WARMER H85 AIR WILL PUSH EAST WITH H85 TEMPS SAT AFTERNOON OF 4 TO 8C. INHERITED FCST OF 40S TO LOWER 50S SATURDAY ARE ON TRACK. A PACIFIC COOL FRONT WILL PUSH INTO THE FORECAST AREA SUNDAY AFTERNOON. HIGHS WILL FALL BACK TO MORE SEASONAL LEVELS SUNDAY...MONDAY AND TUESDAY. WITH THE FRONTAL PASSAGE...THERE WILL BE A SMALL THREAT FOR RAIN OR SNOW SHOWERS SUNDAY...FOLLOWED BY A SLIGHT CHANCE FOR SNOW ON SUNDAY NIGHT. BEYOND TUESDAY...THE LATEST ECMWF AND GFS SOLNS DEVELOP A ZONAL FLOW PATTERN NEXT WEEK WITH ARCTIC AIR WELL NORTH OF THE CWA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1122 PM CST TUE JAN 19 2016 THE MVFR/LOCAL IFR CIGS HAVE MOVE RAPIDLY EAST. IT IS QUITE LIKELY VFR WOULD PREVAIL ALL AREAS FROM 15Z WEDNESDAY ONWARD. SOME TIME WEDNESDAY EVENING...MVFR CIGS WILL DEVELOP FROM NORTH TO SOUTH ASSOCIATED WITH A STRONG COLD FRONT. SNOW MAY BE UNDERWAY ACROSS SHERIDAN COUNTY LATE WEDNESDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 9 AM CST /8 AM MST/ WEDNESDAY FOR NEZ005>010. && $$ UPDATE...CDC SYNOPSIS...BUTTLER SHORT TERM...MASEK LONG TERM...BUTTLER AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1231 AM CST WED JAN 20 2016 .UPDATE... ISSUED AT 1230 AM CST WED JAN 20 2016 VISIBILITIES HAVE LOWERED TO 1/4 MILE OVER NORTHWESTERN AND NORTH CENTRAL NORTH DAKOTA WITHIN THE BOUNDARIES OF THE DENSE FOG ADVISORY. OTHER AREAS...MAINLY SOUTH CENTRAL NORTH DAKOTA...HAVE REDUCED VISIBILITIES OF 1/2 TO 2 MILES OR MORE BUT EXPECT DETERIORATING VISIBILITIES THERE AS WELL. CURRENT DENSE FOG ADVISORY LOOKS VALID FOR THE MORNING HOURS. ONLY OTHER CONCERN WAS TEMPERATURES...AS TEMPERATURES IN THE NORTHWEST HAVE LOWERED MORE THAN EXPECTED...AND HAD TO ADJUST LOWS TO AROUND ZERO OR BELOW IN A LARGE AREA MAINLY EXTENDING FROM CROSBY TO BEULAH/HAZEN. CONFIDENCE IS LOW REGARDING HOURLY TEMPERATURE TRENDS...AS SOME AREAS TEMPS ARE GOING DOWN AND OTHER AREAS (JAMES VALLEY) WITH SOUTH WINDS AND TEMPERATURES ARE FAIRLY STEADY. SHORT TERM MODELS DO NOT HAVE THIS DETAIL IN THEIR OUTPUTS. UPDATE ISSUED AT 826 PM CST TUE JAN 19 2016 QUICK UPDATE TO EXPAND THE DENSE FOG ADVISORY INTO MCKENZIE...DUNN...GRANT AND SIOUX COUNTIES PER OBSERVED TRENDS 0230 UTC. UPDATE ISSUED AT 721 PM CST TUE JAN 19 2016 WEBCAM AND SURFACE OBSERVATION TRENDS THROUGH 0115 UTC DEPICT VISIBILITY RAPIDLY FALLING ACROSS NORTHWEST AND INTO CENTRAL NORTH DAKOTA WITH STRATUS BUILD DOWN. THUS...HAVE ISSUED A DENSE FOG ADVISORY FOR THESE AREAS THROUGH 16 UTC WEDNESDAY MORNING. THE SPATIAL COVERAGE OF THE ADVISORY IS FITTED TO CURRENT AREAS WITH DENSE FOG...EXTRAPOLATED TO VISIBILITY TRENDS IN THE 21-00 UTC HRRR ITERATIONS. A POTENTIAL EXPANSION OF THE ADVISORY IS POSSIBLE LATER THIS EVENING. UPDATE ISSUED AT 637 PM CST TUE JAN 19 2016 GIVEN TRENDS IN THE 21-23 UTC HRRR ITERATION VISIBILITY FORECASTS...EXPANDED THE MENTION OF FOG TO ALL OF WESTERN AND CENTRAL NORTH DAKOTA TONIGHT INTO WEDNESDAY MORNING. PATCHY DENSE FOG HAS ALREADY DEVELOPED ACROSS NORTHWEST NORTH DAKOTA AS OF 00 UTC...AND EXPECT A SLOW EXPANSION OF FOG WITH STRATUS BUILD DOWN THROUGH THE NIGHT. A DENSE FOG ADVISORY MAY BE NEEDED. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 229 PM CST TUE JAN 19 2016 LOOKS LIKE THE VERY COLD AIR WILL TAKE AN EXIT FOR AWHILE. CONCERNS NOW FOR THIS SHORT TERM PERIOD WILL FOCUS ON THE POTENTIAL FOR FOG TONIGHT. MESOSCALE MODELS HAVE BEEN CONSISTENTLY FORECASTING A SHALLOW COOL AND MOIST BOUNDARY LAYER FREE OF CLOUDS ABOVE. HRRR DEVELOPS WIDESPREAD LOW VISIBILITIES THIS EVENING AND OVERNIGHT. SATELLITE TRENDS SO FAR TODAY SHOW THE STRATUS LAYER ERODING IN LOW LEVEL WARM ADVECTION ACROSS WESTERN NORTH DAKOTA. THIS PROCESS WILL BE DISRUPTED THIS EVENING AS SUNSET APPROACHES. DURING THE COOLING HOURS IN THE EVENING EXPECT FOG TO FORM IN THE CLEARING ZONE WITH THE CLOUDS CREEPING BACK WEST. THIS WILL MAKE MIN TEMPERATURES IN THE CLEARING AREA A CHALLENGE. SO FAR HAVE ACCEPTED THE CONSSHORT GUIDANCE GIVING LOWER TEENS ACROSS THE WEST AND SINGLE DIGITS ABOVE ZERO EAST. ON WEDNESDAY THE NEXT SHORTWAVE IN A SERIES OF SHORTWAVES WILL BRING AN INCREASE IN MID/HIGH CLOUDS AND BREAK OF THE BOUNDARY LAYER FOG DURING FORENOON. A SLIGHT CHANCE OF SNOW SEEMS REASONABLE BY LATE AFTERNOON FAR WEST. HIGH WEDNESDAY IN THE 20S TO MID 30S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 229 PM CST TUE JAN 19 2016 WEDNESDAY NIGHT THROUGH THURSDAY...COLD AIR ADVECTION AND A CHANCE OF LIGHT SNOW WILL BEGIN POURING INTO SOUTHWEST NORTH DAKOTA WEDNESDAY EVENING AS A SURFACE LOW AND ASSOCIATED MID LEVEL SHORTWAVE SCOOT FROM SOUTHEAST MONTANA INTO SOUTH DAKOTA. THIS WILL BE FOLLOWED BY ANOTHER SHORTWAVE THURSDAY...AS IT MOVES FROM WEST TO EAST DURING THE DAY. THERE HAD BEEN SOME CONCERN FOR LIGHT FREEZING RAIN WEDNESDAY EVENING...BUT THE NAM/SREF/GFS BUFKIT SOUNDINGS INDICATE THAT IF IT DID DEVELOP...IT WOULD BE BRIEF...WITH A FAIRLY QUICK TRANSITION TO LIGHT SNOW. NOT SEEING AN EXTENDED PERIOD OF UPWARD VERTICAL MOTION WITH WITHIN THE SUPERCOOLED WATER DROPLET REGIME...AND THE TRANSITION TIME FOR ANY GIVEN SOUNDING TO REACH COLDER/HIGHER LEVELS OF SATURATION IS ACHIEVED FAIRLY QUICKLY WEDNESDAY NIGHT. THUS...GIVEN THE BRIEF TIME AND ISOLATED COVERAGE OF LIGHT FREEZING RAIN POTENTIAL...HAVE DECIDED TO STICK WITH THE GIVEN FORECAST WHICH KEEPS A MENTION OF ONLY LIGHT SNOW. WILL REVISIT THE SOUNDINGS AGAIN TONIGHT AND WEDNESDAY FOR ANY SIGNIFICANT CHANGES TO THE ABOVE THINKING. OTHERWISE...CHANCES FOR LIGHT SNOW WILL EXPAND INTO CENTRAL NORTH DAKOTA THROUGH THE DAY THURSDAY. SNOWFALL ACCUMULATIONS THROUGH THURSDAY EVENING ARE FORECAST AROUND A HALF INCH WEST AND CENTRAL...WITH AN ISOLATED SPOT OF ONE INCH IN THE SOUTHWEST. THE CHANCE OF LIGHT SNOW EXITS THE SOUTHERN JAMES RIVER VALLEY THURSDAY EVENING. WITH ONGOING COLD AIR ADVECTION...HIGH TEMPERATURES THURSDAY WILL BE 5 TO 10 DEGREES COLDER FROM WEDNESDAY...WHICH PUTS HIGHS THURSDAY FROM AROUND 10F ABOVE IN THE TURTLE MOUNTAINS TO 25F SOUTHWEST. THURSDAY NIGHT THROUGH SATURDAY...FOLLOWING THE ABOVE SHORTWAVE IS AN UPPER LEVEL RIDGE WHICH WILL SHIFT FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH PLAINS FRIDAY INTO MOST OF SATURDAY. STRONG LOW LEVEL WARM AIR ADVECTION FRIDAY AND SATURDAY WILL RESULT IN A MODERATING TREND ALONG WITH DRY CONDITIONS. HIGHS FRIDAY WILL RANGE FROM AROUND 20 IN THE JAMES RIVER VALLEY TO 40 WEST. BY SATURDAY HIGHS WILL RANGE BETWEEN 30F AND 40F ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE WARMING TREND WILL COME TO AN END SATURDAY EVENING...AS A COLD FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST. THIS LEADS TO A CHANCE OF SNOW AND COLDER TEMPERATURES SUNDAY. HIGHS SUNDAY THROUGH TUESDAY ARE NEARLY THE SAME EACH DAY WITH HIGHS IN THE UPPER TEENS IN THE TURTLE MOUNTAINS TO 20S ELSEWHERE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1230 AM CST WED JAN 20 2016 WIDESPREAD LIFR/VLIFR CONDITIONS IN FOG AND STRATUS EXPANDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH WEDNESDAY MORNING. AFTER A BRIEF RETURN TO VFR CONDITIONS AT SOME LOCATIONS WEDNESDAY AFTERNOON...EXPECT MVFR CONDITIONS AGAIN WEDNESDAY EVENING. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST /9 AM MST/ THIS MORNING FOR NDZ001-002-009>011-017>023-034>036-042-045>047-050. && $$ UPDATE...JV SHORT TERM...WAA LONG TERM...KS AVIATION...JV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 AM EST WED JAN 20 2016 .SYNOPSIS... AN UPPER LEVEL TROUGH ALONG WITH AN UPPER LEVEL DISTURBANCE WILL COMBINE TO BRING SNOW TO THE AREA WEDNESDAY. HIGH PRESSURE AND DRY AIR WILL RETURN FOR THURSDAY...UNTIL A LARGE AREA OF LOW PRESSURE BRINGS ANOTHER WINTER SYSTEM TO THE REGION ON FRIDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... HIGH CLOUDS ARE SPREADING INTO THE FORECAST AREA THIS EVENING...AND RADAR ECHOES HAVE EXTENDED INTO SOUTHWEST INDIANA. SOME OF THESE ECHOES ARE VIRGA...WITH THE INITIAL AREAS OF SNOW JUST NOW REACHING SOUTHERN ILLINOIS. BASED ON CURRENT TRENDS AND RECENT HRRR/RAP FORECAST CYCLES...THE TIMING FOR SNOW WAS SPED UP SLIGHTLY. ALSO...POPS WERE INCREASED TO 100 PERCENT FOR MUCH OF THE FORECAST AREA. THE LATEST GUIDANCE SUGGESTS THAT THE CURRENT SNOWFALL FORECAST IS STILL ON TRACK...FALLING VERY CLOSE TO THE SREF MEAN...AND IN BETWEEN THE HIGHER NAM AND LOWER RAP SOLUTIONS. PREVIOUS DISCUSSION > CURRENTLY MOSTLY CLEAR SKIES WITH SOME PASSING CIRRUS AS THE NEXT UPPER LEVEL SYSTEM CAN CLEARLY BE SEEN ON VISIBLE OFF TO OUR WEST. WEDNESDAY MORNING AN UPPER LEVEL TROUGH WILL DIVE SOUTHEAST AND PUSH INTO OUR FAR WESTERN ZONES BETWEEN 4 AM AND 7 AM. OMEGA VALUES ON BOTH THE GFS AND NAM SHOW WEAK LIFT MOVING ACROSS THE AREA RIGHT AROUND 6 AM ALONG WITH ISENTROPIC UPGLIDE COMMENCING. THINK THE ONSET OF SNOW MIGHT BE DELAYED A BIT AS GFS AND NAM FORECAST SOUNDINGS SHOW DRY AIR AROUND 750 MB SLOWLY ERODING WEDNESDAY MORNING. THIS MAKES SENSE AS 12 Z 700 MB ANALYSIS SHOWED DEWPOINT DEPRESSIONS OF GREATER THAN 20 DEGREES JUST OFF TO OUR WEST. LATEST SUITE OF HIGH RES AND GLOBAL MODELS HAVE SHOWN A SLIGHT INCREASE IN AMOUNTS OF SNOWFALL ACROSS THE AREA BUT AM EXPECTING 1-2 INCHES WITH HIGHER AMOUNTS POSSIBLE ACROSS THE SOUTHWEST OF THE CWA. THE TIMING OF THE SNOWFALL ALSO LOOKS TO OCCUR DURING THE MORNING COMMUTE. GIVEN THE POTENTIAL IMPACTS DURING THE MORNING COMMUTE AND SLIGHTLY HIGHER TOTALS HAVE EXTENDED THE WINTER WEATHER ADVISORY ONE TIER OF COUNTIES NORTH. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... WEDNESDAY MORNING WILL START OFF WITH SNOW SPREADING ACROSS THE CWA WITH HIGHER TOTALS FORECASTED ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS ON THE NAM AND GFS THEN SHOW THE SNOW STARTING TO COME TO AN END WEST TO EAST BETWEEN NOON AND 2 PM. ACROSS OUR FAR EASTERN COUNTIES SNOW SHOULD COME TO AN END BY 7 PM. FORECAST SOUNDINGS ON BOTH THE GFS AND NAM ALSO SHOW DRY AIR STARTING TO MOVE IN AT 500 MB AS THE MAIN SHORTWAVE MOVES OVERHEAD. THE DGZ APPEARS TO BE BETWEEN 550 AND 700 MB. THE DEWPOINT AND TEMPERATURE LINES ON THE FORECAST SOUNDINGS CONTINUE TO PULL APART IN THE AFTERNOON. THIS WILL BRING AN END TO THE SNOW. THE TEMPERATURE PROFILE IS ALSO ISOTHERMAL RIGHT AROUND -10 DEGREES FROM 900 TO 700 MB. A LITTLE COLDER PROFILE WILL KEEP THE SNOW GOING SLIGHTLY LONGER AS ICE CRYSTALS WILL BE ABLE TO GROW WHERE AS A SLIGHTLY WARMER PROFILE WOULD FAVOR A QUICKER END TO THE SNOW AND A POSSIBLE BRIEF PERIOD OF DRIZZLE. FOR NOW HAVE LEFT THE MENTION OF DRIZZLE OUT AS CONFIDENCE REMAINS LOW. WEDNESDAY EVENING SNOW WILL COME TO AN END AS A WEAK COLD FRONT CROSSES THE AREA. SURFACE HIGH PRESSURE WILL THEN MOVE OVERHEAD THURSDAY MORNING ALLOWING WINDS TO GO CALM. THURSDAY MORNING THE GFS... EURO AND NAM ALL SHOW A CIRRUS SHIELD MOVING IN FROM THE SOUTHWEST ALONG WITH SOME LOW CLOUDS LINGERING. GIVEN THE ABOVE... LOW TEMPERATURES THURSDAY MORNING WILL LIKELY BE A TAD WARMER THAN WEDNESDAY MORNINGS TEMPS. DURING THE DAY THURSDAY CIRRUS WILL CONTINUE WITH SURFACE RIDGING WEAKENING ACROSS THE AREA AS THE NEXT SYSTEM APPROACHES FROM THE WEST. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MAIN FOCUS IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR A WINTER STORM TO AFFECT THE OHIO VALLEY REGION. THE IMPETUS FOR WHAT WILL DEVELOP INTO A CLOSED MID LEVEL CIRCULATION EITHER OVER THE TN VLY OR THE DEEP SOUTH IS STILL OFF THE WEST COAST ATTM...SO CAUTION MUST BE USED IN THE FORECAST DUE TO THE OSCILLATIONS IN THE POSITION AND TRACK OF THE MID LEVEL CIRCULATION. MODELS TEND TO HAVE ISSUES WITH THE CLOSING OFF OF SUCH SYSTEMS...AND GIVEN THAT THE ENERGY IS STILL OFF THE WEST COAST...THERE WILL BE TIME FOR OSCILLATIONS TO CONTINUE UNTIL PERHAPS 12Z WEDNESDAY WHEN THE ENERGY WILL BE FULLY SAMPLED. THAT BEING SAID...OF THE MAIN OPERATIONAL MODELS FROM THE 01.19.12Z RUN...THE ECMWF HAS TAKEN A MORE SOUTHERN TRACK ACROSS THE DEEP SOUTH VERSUS THE OTHER MODELS (NAM...GFS...AND CMC). AS TO NOT JUMP ON THE PURE 12Z ECMWF SOLUTION...WHICH WOULD BRING A PCPN SHIELD/MID LEVEL DEFORMATION AXIS ONLY AS FAR NORTH AS THE OHIO RIVER...HAVE TAKEN A BLEND OF THE 12Z GFS AND THE PREVIOUS 00Z ECMWF WHICH KEEPS SOME CONTINUITY TO THE GOING FORECAST AND ALLOWS FOR SOME POTENTIAL FOR A MORE NORTHERN TRACK TO BE A POSSIBLE SOLUTION. THUS...THE CURRENT FORECAST WILL ALLOW PCPN SHIELD/MID LVL DEFORMATION AXIS PUSH NORTHWARD TOWARD THE OHIO RIVER THURSDAY NIGHT...ALLOWING IT TO PIVOT AS FAR NORTH/NORTHWEST AS THE I-71 CORRIDOR...AND THEN ALLOW IT TO SHIFT EAST FRIDAY NIGHT INTO SATURDAY AS A COASTAL LOW/ENERGY TRANSFER TAKES PLACE. BASED ON THIS SCENARIO...PCPN SHOULD REMAIN AS SNOW WITH THE POTENTIAL FOR SIGNIFICANT SNOW ACCUMULATIONS ALONG AND SOUTHEAST OF THE I-71 CORRIDOR AND PARTICULARY ALONG AND SOUTH OF THE OHIO RIVER VALLEY. THUS...AT THIS JUNCTURE...4 OR MORE INCHES OF SNOW MAY BE POSSIBLE ALONG AND SOUTH OF THE I-71 CORRIDOR WITH 6 OR MORE INCHES POSSIBLE ALONG AND SOUTH OF THE OHIO RIVER. AGAIN...A TRACK FARTHER SOUTH WOULD ONLY IMPACT LOCATIONS ALONG AND SOUTH OF THE OHIO RIVER...AND A TRACK FARTHER NORTH WOULD PUSH THE THREAT TOWARD THE I-71 CORRIDOR. AS THE COASTAL LOW TAKES SHAPE AND MOVES NEAR AND OFF THE NEW ENGLAND COAST SATURDAY AFTERNOON AND NIGHT...PCPN WILL TAPER OFF OVER THE REGION AS SURFACE HIGH PRESSURE BUILDS BACK INTO THE OHIO VALLEY. AS FOR TEMPERATURES...HAVE TAKEN BLEND OF PREVIOUS FORECAST AND THE 12Z GFS/00Z ECMWF. SOME ADJUSTMENTS MAY HAVE TO BE MADE TO CURRENT VALUES DEPENDING ON WHERE AND THE AMOUNT OF SNOW COVER WHICH MAY FALL...WHICH WILL HAVE AN ALBEDO EFFECT/RADIATIONAL COOLING EFFECT. FOR SUNDAY INTO MONDAY...HIGH PRESSURE WILL MOVE OFF TO THE EAST AS THE NEXT LOW PRESSURE SYSTEM AND FRONT MOVE IN FROM THE WEST. THERE ARE SOME TIMING AND STRENGTH DIFFERENCE AT THIS POINT...SO WILL BRING A GRADUAL CHANCE OF PCPN FROM WEST TO EAST MONDAY AFTERNOON INTO MONDAY NIGHT...WITH THE CHANCE CONTINUING INTO TUESDAY AS THE SYSTEM MOVES THROUGH. TEMPERATURES WILL BE CRITICAL TO PTYPE. CURRENTLY HAVE RAIN/SNOW FOR NORTHERN AREAS AND RAIN FOR SOUTHERN AREAS...WITH A CHANGEOVER TO ALL SNOW ON TUESDAY IN THE WAKE OF THE LOW AND FRONT. A BLEND OF THE TEMPERATURES HAVE BEEN USED WITH HIGHS IN THE 30S TO AROUND 40 AND LOWS MAINLY IN THE 30S. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... FAST MOVING STORM SYSTEM WILL BRING SNOW TO THE TAFS MAINLY BETWEEN 10Z-18Z TODAY. WHEN THE SNOW ARRIVES...VSBYS WILL DROP TO IFR...WITH MVFR CIGS EXPECTED. BEHIND THE SNOW...MODELS ARE HOLDING LOW LEVEL MOISTURE AND IFR CIGS PAST 00Z. NAM IS MOST ENTRENCHED WITH LOWS...HOLDING THEM ALL THE WAY THROUGH 30 HOURS. OTHER MODELS ARE NOT QUITE AS PESSIMISTIC...BUT WILL LEAN TOWARDS THE NAM...AS IT SEEMS THAT THE LOW CLOUDS ARE SOMETIMES HARD TO GET OUT OF THE REGION THIS TIME OF THE YEAR. OUTLOOK...MVFR/IFR CONDITIONS ARE EXPECTED WITH PRECIPITATION ON FRIDAY INTO SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM EST THIS EVENING FOR OHZ070>072-077>081-088. KY...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM EST THIS EVENING FOR KYZ089>100. IN...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM EST THIS EVENING FOR INZ066-073>075-080. && $$ SYNOPSIS...HAINES NEAR TERM...HAINES/HATZOS SHORT TERM...HAINES LONG TERM...HICKMAN AVIATION...SITES
AREA FORECAST DISCUSSION
NWS Tulsa OK
1139 PM CST TUE JAN 19 2016 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. Areas of freezing drizzle continue over portions of NE OK and NW AR late this evening. The heavier precipitation will begin to shift east of the region around 08z. Low clouds/fog however will continue overnight and likely persist through much of the day Wednesday as surface winds slowly return to the southeast. && .PREV DISCUSSION... /ISSUED 909 PM CST TUE JAN 19 2016/ ..UPDATE... DISCUSSION... Precipitation across far eastern OK and northwest AR has been convection in nature...resulting in pockets of brief moderate sleet/freezing rain this evening. This has made for very slick conditions across the region...especially in and around the Fort Smith area and into parts of Madison county. HRRR trends are for the heavier precipitation to shift east of the region after 06z...although could see a few more hours of light freezing drizzle. Will leave the winter weather advisory as is for now...but it may end of being cancelled a bit earlier than 12z. && .TSA Watches/Warnings/Advisories... OK...Winter Weather Advisory until 6 AM CST Wednesday for OKZ057-058- 062-063-068-069-072. AR...Winter Weather Advisory until 6 AM CST Wednesday for ARZ001-002- 010-011-019-020-029. && $$ AVIATION...12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1154 PM CST TUE JAN 19 2016 .UPDATE... FOR 06Z AVIATION DISCUSSION. && .DISCUSSION... LATEST SURFACE ANALYSIS DEPICTS SNOW ACROSS THE NORTHERN HALF OF MO. FREEZING RAIN AND SOME SLEET OVER SRN MO...SOME FRZ RAIN ACROSS NRN AR. 00Z OHX SOUNDING REVEALED 850 MB TEMPS THAT WERE SLIGHTLY WARMER THAN THE MODELS. WET BULB ZERO PROFILES AT THE 850 MB LEVEL SHOWS A RATHER IMPRESSIVE WEDGE OF WARMING ACROSS AR. PORTIONS OF NRN AR AND SRN MO SHOW FRZ RA WITH TEMPS IN THE LOWER TO MID 20S...A TESTAMENT AS TO THE DEGREE OF WARM WEDGING THAT IS ON GOING. SFC LOW IS CURRENTLY LOCATED OVER ERN OK. SLIGHT INCREASE IN STRENGTH IS EXPECTED WITH THE WARM AIR IN THE 800MB TO 900 MB LEVEL WORKING EASTWARD. THIS WARMER AIR MAY VERY WELL MAKE IT INTO OUR SOUTHWESTERN COUNTIES PRIOR TO 12Z. THUS...I WILL GO AHEAD AND INCLUDE MORE IN THE WAY OF SLEET AND FREEZING RAIN ACROSS OUR SOUTHWESTERN AND SOUTH CENTRAL AREAS. LATEST HRRR SHOWS PATCHY LIGHT PRECIP MAKING IT ACROSS THE TN RIVER AND REACHING THE GROUND JUST AFT MIDNIGHT. THE MORE SIGNIFICANT PRECIP APPEARS TO MAKE IT ACROSS THE TN RIVER RIGHT AROUND 6 AM. BASED ON THE LATEST 18Z NAM SOUNDINGS...IT STILL LOOKS LIKE ALL SNOW NORTH OF I-40. BUT...THAT SOUTHWEST AREA IS A CONCERN AND MORE IN THE WAY OF SLEET AND FREEZING RAIN COULD FALL. AGAIN...WILL OPT TO MODIFY THE WX GRIDS TO REFLECT THIS ACROSS SOUTHWEST AND SOUTH CENTRAL AREAS. SFC TEMPS STILL EXPECTED TO WARM ABOVE FREEZING ACROSS THE SOUTHWEST BY 9AM...AND THEN ALL BUT THE PLATEAU AREA BY NOON. UPDATE OUT SHORTLY. && .AVIATION... 06Z TAF DISCUSSION. COMPLICATED AVIATION WX FORECAST SCENARIO WITH POTENTIAL ICING CONCERNS DUE TO FROZEN PCPN DEVELOPMENT CONTINUES. LATEST SHORT RANGE MODEL CONSENSUS CONTINUING TO SHOW THAT ORGANIZED FROZEN PCPN DEVELOPMENT BEGINS BY 20/08Z...LASTING CKV/BNA THRU 20/18Z...WITH CONTINUANCE OF FROZEN PCPN IMPACTING CSV THRU 21/00ZZ. BEST ICING WINDOW PER FREEZING RAIN POTENTIAL CKV/BNA 20/13Z-20/18Z AND CSV 20/18Z-20/24Z. CKV/BNA SHOULD EXPERIENCE A TRANSITION TO LIGHT RAIN 20/18Z-21/00Z. MOST OF MOISTURE EXPECTED TO MOVE EAST OF MID STATE 21/00Z-21/06Z...BUT A WEAK DISTURBANCE IN NWLY FLOW ALOFT BEFORE SUBTLE UPPER LEVEL RIDGING INFLUENCES BUILD INTO THE MID STATE MIGHT RESULT IN LIGHT FREEZING DRIZZLE BNA/CKV 21/02Z-21/06Z. CURRENT VFR CEILINGS ARE EXPECTED TO LOWER TO STRATUS MVFR CEILINGS 20/07Z CKV-20/12Z CSV. CEILINGS WILL EVENTUALLY LOWER INTO IFR/LIFR THRESHOLDS 20/18Z-21/06Z. EXPECT PCPN TO RESULT IN LOWERING CURRENT VFR VSBYS TO IFR 20/12Z-20/18Z WITH SOME IMPROVEMENT TO MVFR VSBYS CKV/BNA 20/18Z-21/06Z. && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR BEDFORD- CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-DAVIDSON-DE KALB-DICKSON- FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-HUMPHREYS-JACKSON-LAWRENCE- LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-OVERTON-PERRY-PICKETT- PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-SUMNER-TROUSDALE-VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON. && $$ SHORT TERM/AVIATION........31 LONG TERM..................21
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1203 AM CST WED JAN 20 2016 .AVIATION... NO SIGNIFICANT CHANGES TO PREVIOUS TAF PACKAGE. A WEAK COLD FRONT IS STILL ON TAP TO CROSS THE FORECAST AREA DURING THE EARLY MORNING HOURS. THE FRONT SHOULD MOVE ACROSS THE WESTERN TERMINALS BETWEEN 08-10Z AND THE HOUSTON METRO AREA BETWEEN 11-14Z...AND OFF THE COAST BETWEEN 15-18Z...RESULTING IN A N/NW WIND SHIFT. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT AS IT SAGS SOUTHWARD. VFR CONDITIONS POSSIBLE TOMORROW AFTERNOON TO THE NORTH OF I-10 BEHIND THE FRONT...HOWEVER MVFR CIGS LIKELY TO REMAIN IN PLACE BETWEEN HOUSTON METRO AREA AND THE COAST. THE FRONT SHOULD STALL OUT NEAR THE COAST TOMORROW AFTERNOON BEFORE IT BEGINS TO MOVE INLAND AS A WARM FRONT. MVFR/IFR CIG CONDITIONS AND AREAS OF FOG LIKELY TOMORROW NIGHT BETWEEN CONROE AND THE COAST. 44 && .PREV DISCUSSION... /ISSUED 914 PM CST TUE JAN 19 2016/ DISCUSSION... SFC ANALYSIS AT 03Z SHOWED COLD FRONT STRETCHING FROM N TX THROUGH W C TX WITH A FEW SHOWERS ALONG IT SE OF THE METROPLEX. BASED ON LATEST HRRR TRENDS AND 00Z NAM...FRONT SHOULD CONTINUE TO PUSH SOUTH INTO THE AREA THROUGH THE MORNING. FRONT MAY BE SLOW TO RETURN NORTH AS A WARM FRONT TOMORROW. STRONGER SHORT WAVE TROUGH PUSHES BY ON THURSDAY SO THINK THAT WILL SUPPORT BETTER RAIN CHANCES AND PROBABLY SOME THUNDERSTORMS GIVEN ENOUGH INSTABILITY. THAT SAID...MAY GET A DRY SLOT TO PUSH THROUGH AND KICK STORMS EAST. MAIN CHANGES TO THE FORECAST WERE TO UPDATE T/TD AS WELL AS POP/WX/QPF FOR ONGOING TRENDS AND NEW MODEL GUIDANCE. 39 PREV DISCUSSION... /ISSUED 600 PM CST TUE JAN 19 2016/ AVIATION... VFR CEILINGS THIS EVENING SHOULD GRADUALLY BECOME MVFR BETWEEN 06-09Z AS THE SOUTHERLY FLOW CONTINUES TO DRAW ADDITIONAL LOW LEVEL MOISTURE IN TO THE AREA AHEAD OF AN APPROACHING COLD FRONT. OVERNIGHT WINDS WILL BE LIGHT...BUT SHOULD PRODUCE ENOUGH MIXING IN THE BOUNDARY LAYER TO INHIBIT WIDESPREAD FOG FORMATION. A WEAK COLD FRONT SHOULD MOVE ACROSS THE WESTERN TERMINALS BETWEEN 07-09Z AND THE HOUSTON METRO AREA BETWEEN 12-15Z...AND OFF THE COAST BETWEEN 15-18Z...RESULTING IN A N/NW WIND SHIFT. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ALONG AND AHEAD OF THE FRONT AS IT SAGS SOUTHWARD...SO I CONTINUE TO CARRY A VCSH MENTION FOR ALL TERMINALS. THE FRONT IS EXPECTED TO REACH THE COAST...HOWEVER THE NORTH FLOW WILL BE SHORT LIVED AT TERMINALS TO THE SOUTH OF I-10. WINDS SHOULD BECOME LIGHT AND VARIABLE OVER THE HOUSTON METRO AREA AND VEER TO THE NORTHEAST AT TERMINALS CLOSER TO THE COAST BY TOMORROW AFTERNOON. 44 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 45 60 54 65 38 / 30 10 30 40 10 HOUSTON (IAH) 53 66 57 70 41 / 20 30 30 50 10 GALVESTON (GLS) 58 63 59 69 44 / 20 30 10 40 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39 AVIATION/MARINE...44
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1058 AM EST WED JAN 20 2016 ...HEAVY BAND OF PRECIP CURRENTLY PUSHING ACROSS FAR NORTH GEORGIA COULD PRODUCE SOME LOCALLY HIGHER ICE ACCUMULATIONS TO NEAR A QUARTER INCH WITHIN THE CURRENT WINTER STORM WARNING AREA... .UPDATE... IMPRESSIVE BAND OF HEAVIER PRECIP IMPINGING INTO NW CWA WITH SOME LIGHT MORE ISOLATED RETURNS AHEAD OF ASSOCIATED DISTURBANCE. SO FAR HAVE HAD SOME REPORTS OF FZRA AND SLEET BUT MAINLY IN FAR NORTH AND MAIN CONCERN OF IMPACTFUL ACCUMULATIONS WILL BE WITH APPROACHING BAND AS EVAP COOLING MECHANISM HAS SHOWN SOME SFC TEMP DROPS OF 2-3 DEG. GIVEN THE STILL LOW DWPTS ACROSS THE FAR NORTHERN TIER WITH VALUES STILL IN UPPER TEENS TO LOW 20S AT SOME SPOTS...COULD SEE SOME ISOLATED HIGHER ICE ACCUMULATIONS AROUND 0.25 INCHES. ALSO THE HRRR SO FAR LOOKS TO HAVE DECENT HOLD ON TRENDS WITH P-TYPE AND HAVE ADJUSTED POPS AND WINTER GRIDS ACCORDINGLY. HRRR PROGGED WETBULB TEMPS KEEP THE NE HIGHER ELEVATIONS AROUND 30 DEG THROUGH THE AFTERNOON ALONG WITH A TRANSITION FROM INITIAL MIXED P-TYPE TO PRIMARILY SNOW SO HAVE INCREASED THE LOWER BOUND SNOW AMOUNTS TO NEAR HALF AN INCH SLIGHTLY FARTHER SOUTHEAST TO NEAR GAINESVILLE AND EASTWARD. AS FAR AS NEAR THE METRO...OVERNIGHT TEMPS WERE THANKFULLY ABOUT 4 DEGREES WARMER THAN FCST SO TRENDS HAVE BEEN TO RISE TO 34-36 DEGREES FROM THE WEST. ALL IN ALL HAVE NOT ADJUSTED ANY EXTENT OR TIMING TO THE CURRENT ADVISORY AND WARNING AREAS. PREVIOUS DISCUSSION FOLLOWS... BAKER && .PREV DISCUSSION... /ISSUED 652 AM EST WED JAN 20 2016/ PREV DISCUSSION... /ISSUED 437 AM EST WED JAN 20 2016/ .SHORT TERM /TODAY THROUGH THURSDAY/... SHORT TERM FORECAST CONTINUES TO BE A CHALLENGE WITH IMPACTFUL WINTRY PRECIPITATION EXPECTED ACROSS NORTH GEORGIA. UPPER LEVEL DISTURBANCE WILL INTERACT WITH COLD AND DRY CONDITIONS ACROSS THE AREA TO PRODUCE A WINTRY MIX OVER PORTIONS OF NORTH GEORGIA. ALTHOUGH MODELS HAVE SLOWED THE ONSET TIMING SLIGHTLY BY AN HOUR OR SO...CONSENSUS IS THAT PRECIPITATION WILL BEGIN AS SNOW THIS MORNING...THEN TRANSITION TO FREEZING RAIN/SLEET AND THEN TRANSITION TO ALL SNOW IN THE NE MOUNTAINS BY THE AFTERNOON. ACCUMULATING WINTRY MIX IS EXPECTED AS FAR SOUTH AS PORTIONS OF THE NORTHERN ATLANTA SUBURBS...BUT STILL COULD SEE SOME NON-ACCUMULATING MIX AS FAR SOUTH AS I-20. ALREADY SEEING SOME LIGHT RETURNS ON RADAR ACROSS AL/NORTHERN GEORGIA...BUT SO FAR NOTHING REACHING THE GROUND. MODELS CONTINUE TO SUGGEST THIS TO BE AN OVERALL LOW QPF EVENT...WITH LIQUID EQUIVALENT ONLY A QUARTER INCH OR LESS. WPC WWD GUIDANCE HAS BACKED OFF SOMEWHAT ON SNOWFALL TOTALS...BUT HAS SPREAD THE ACCUMULATING FREEZING RAIN AMOUNTS FARTHER SOUTH. GIVEN THE TIMING OF THE PRECIPITATION ONSET AND THE EXPECTED WARMING TEMPERATURES /PARTICULARLY ACROSS THE METRO AREA/ HAVE OPTED NOT TO DEVIATE TOO FAR FROM THE PREVIOUS SNOW/ICE AMOUNTS PREVIOUSLY FORECAST...A LITTLE MORE CONSERVATIVE IN AREAL COVERAGE THAN THE WWD ICE GRID. THE WINTER STORM WARNING AND THE WINTER WEATHER ADVISORY CONTINUE WITH NO CHANGES MADE TO THE TIMING OR AREA. STILL ANTICIPATE UP TO 2- 2.5 INCHES OF SNOW IN THE WSW /PARTICULARLY IN THE NE GA MOUNTAINS/ AND UP TO A TENTH OF AN INCH OF ICE. IN THE ADVISORY AREA UP TO 1 INCH OF SNOW AND A TENTH OF AN INCH OF ICE CAN BE EXPECTED. WITH COLD ANTECEDENT CONDITIONS...IMPACTS ARE EXPECTED AT ONSET OF THE PRECIPITATION. HAVE ALSO CONTINUED THE SPECIAL WEATHER STATEMENT FOR SEVERAL COUNTIES JUST SOUTH OF THE ADVISORY AREA TO INDICATE POTENTIAL FOR WINTRY PRECIPITATION MIXED WITH RAIN. THERE REMAINS SEVERAL UNCERTAINTIES WITH THE FORECAST THAT WILL NEED TO BE MONITORED AS THE EVENT UNFOLDS. THE WEAKENING RIDGE AND EROSION OF THE ASSOCIATED LOW LEVEL INVERSION WILL PLAY A KEY ROLE IN DURATION OF WINTER PRECIP. THERMODYNAMIC TRENDS WILL STILL NEED TO BE WATCHED FOR WETBULBING/EVAPORATIVE COOLING EFFECTS AND IF IT DELAYS THE TRANSITION TO OTHER P-TYPES. LINGERING FREEZING TEMPERATURES INTO THE OVERNIGHT HOURS COULD ALLOW FROZEN PRECIP TO CONTINUE AND INCREASE BLACK ICE THREAT. STAY TUNED AS THE FORECAST CONTINUES TO EVOLVE AS THE EVENT UNFOLDS. ALTHOUGH THE PRECIPITATION POTENTIAL DIMINISHES SOMEWHAT OVERNIGHT...ALL RAIN WILL RETURN TO THE AREA THURSDAY AND INTO THE INITIAL EXTENDED FORECAST PERIODS. ANTICIPATE THAT BY MID MORNING THURSDAY ALL OF NORTH AND CENTRAL GEORGIA SHOULD BE SEEING ABOVE- FREEZING TEMPERATURES. 31 && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... SOUTHERN STREAM LOW MOVING INTO THE LOWER MS VALLEY AT THE START OF THE PERIOD...TRACKING THROUGH THE TN VALLEY AND THEN OFF THE MID ATLANTIC COAST BY SATURDAY MORNING. EXPECTING ALL LIQUID PRECIP UNTIL FRIDAY NIGHT AS WRAP AROUND MOISTURE SPREADS INTO THE FORECAST AREA. PARTIAL THICKNESS VALUES WOULD SUPPORT SNOW FOR THE FAR NORTH AND A MIX OF RAIN AND SNOW FOR THE REMAINDER OF NORTH. FOR NOW...HAVE KEPT LIGHT ACCUMULATIONS CONFINED TO THE FAR NORTH SINCE ACTUAL QPF IS STILL QUESTIONABLE. SOME LIGHT WRAP AROUND SNOW IS POSSIBLE SATURDAY FOR THE EXTREME NORTH AS THE LOW CONTINUES TO MOVE NORTHEAST. SUNDAY LOOKS DRY BUT THE NEXT LOW IS MOVING INTO THE MID MS VALLEY BY MONDAY...BRINGING MOISTURE BACK INTO THE FORECAST AREA. PRECIPITATION SHOULD SPREAD ACROSS NORTH AND CENTRAL GEORGIA MONDAY AND TUESDAY. LOOKING FOR ALL RAIN MONDAY AND TUESDAY...HOWEVER LEADING INTO TUESDAY NIGHT THERE IS ANOTHER CHANCE FOR SOME FREEZING OR FROZEN PRECIP ACROSS FAR NORTH GEORGIA. 41 && .AVIATION... 12Z UPDATE... VFR CONDITIONS THIS MORNING WILL DEGRADE TO MVFR AT THE NORTHERN TAF SITES BY LATE AFTERNOON WITH -SHRA BEGINNING. -DZ EXPECTED OVERNIGHT AND CIGS WILL DEGRADE TO IFR. AS -RA RETURNS THURSDAY MORNING CIGS WILL REMAIN IFR. SE WINDS WILL BECOME SW 18-21Z /OR POSSIBLY LATER/ THEN SHIFT BACK TO THE E-SE BY THIS EVENING/OVERNIGHT. SPEEDS GENERALLY 7KT OR LESS. AT SOUTHERN TAF SITES CIGS WILL DEGRADE TO MVFR BY 10-11Z THURSDAY. //ATL CONFIDENCE...12Z UPDATE... MEDIUM ON PRECIPITATION TIMING. HIGH CONFIDENCE ON ALL OTHER ELEMENTS. 31 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 41 33 43 38 / 40 30 70 90 ATLANTA 42 37 47 42 / 40 40 70 90 BLAIRSVILLE 35 31 45 36 / 80 40 70 90 CARTERSVILLE 38 33 46 40 / 70 40 70 90 COLUMBUS 50 43 59 49 / 20 40 60 90 GAINESVILLE 35 32 42 37 / 60 40 70 90 MACON 50 40 54 45 / 20 30 50 70 ROME 37 34 46 41 / 80 40 80 90 PEACHTREE CITY 44 35 49 43 / 40 40 70 90 VIDALIA 54 41 57 47 / 5 10 30 50 && .FFC WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR THE FOLLOWING ZONES: CATOOSA...CHATTOOGA...DADE...DAWSON...FANNIN...GILMER... GORDON...LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...WALKER... WHITE...WHITFIELD. WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR THE FOLLOWING ZONES: BANKS...BARTOW...CHEROKEE...FLOYD...FORSYTH... HALL. && $$ SHORT TERM...31/BAKER LONG TERM....41 AVIATION...31
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1030 AM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO THE FORECAST AREA. THE LATEST HRRR INDICATES PRECIPITATION DIMINISHING AS IT MOVES INTO THE AREA FROM THE WEST LATE THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20 PERCENT SOUTH LATER THIS AFTERNOON. THE TOP-DOWN METHOD RUN ON BOTH THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND SNOW CLOSE TO THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A RAIN AND SNOW MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED ON THE WET BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE RIDGE. FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA. NO SIGNIFICANT IMPACTS ARE EXPECTED BECAUSE OF LIGHT AMOUNTS AND MARGINAL TEMPERATURES. LOWERED AFTERNOON HIGHS A BIT DUE TO A COLD START...CLOUDINESS...AND THE EVAPORATIVE COOLING POTENTIAL. MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. THE PREVIOUS NAM MOS INDICATED A 40 PERCENT POP IN THE SOUTH PART LATE TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A MID-LEVEL SHORTWAVE TROUGH...WITH THE LATEST NAM MOS INDICATING MUCH LOWER POPS. WILL KEEP A SMALL POP IN THE SOUTH PART FOR TONIGHT. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB TEMPERATURES ABOVE FREEZING IN THE SOUTH PART DURING THE PRECIPITATION CHANCE TIME INDICATED BY THE NAM. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW PRESSURE SYSTEM LIFTS NORTHEAST. MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE 1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS REMAINS A LOW CONFIDENCE FORECAST. WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR- SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS AFTERNOON WITH THE AXIS JUST EAST OF THE AREA. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
623 AM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA THROUGH TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO THE FORECAST AREA. THE HRRR...ARW AND SPC WRF INDICATE PRECIPITATION DIMINISHING AS IT MOVES INTO THE AREA FROM THE WEST LATE THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20 PERCENT SOUTH. THE TOP-DOWN METHOD RUN ON BOTH THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND SNOW CLOSE TO THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A RAIN AND SNOW MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED ON THE WET BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE RIDGE. FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA. NO SIGNIFICANT IMPACTS ARE EXPECTED BECAUSE OF LIGHT AMOUNTS AND MARGINAL TEMPERATURES. THE GUIDANCE TEMPERATURES ARE LIKELY TOO HIGH TODAY BECAUSE OF A COLD START...CLOUDINESS...AND THE EVAPORATIVE COOLING POTENTIAL. MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. THE NAM MOS DID INDICATE A 40 PERCENT POP IN THE SOUTH PART LATE TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A MID-LEVEL SHORTWAVE TROUGH. THE GFS AND ECMWF MOS INDICATED A LOWER POP. USED AN AVERAGE OF THE GUIDANCE AND FORECASTED A SMALL POP IN THE SOUTH PART. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB TEMPERATURES ABOVE FREEZING IN THE SOUTH PART DURING THE PRECIPITATION CHANCE TIME INDICATED BY THE NAM. USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW PRESSURE SYSTEM LIFTS NORTHEAST. MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE 1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS REMAINS A LOW CONFIDENCE FORECAST. WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /11Z WEDNESDAY THROUGH SUNDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE ARW...HRRR...AND SPC WRF DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR- SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS AFTERNOON WITH THE AXIS JUST EAST OF THE AREA. USED THE GFS LAMP FOR THE WIND FORECAST. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
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
AREA FORECAST DISCUSSION
NWS GOODLAND KS
308 AM MST WED JAN 20 2016 .UPDATE... ISSUED AT 307 AM MST WED JAN 20 2016 LATEST OBSERVATIONS/TRENDS INDICATE THE FREEZING FOG WILL BE EAST OF THE COLORADO BORDER. HAVE SHIFTED THE COVERAGE OF FOG IN THE FORECAST FURTHER EAST AS A RESULT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 237 AM MST WED JAN 20 2016 LATEST SATELLITE IMAGERY AND UPPER AIR ANALYSIS SHOWS SEMI ZONAL FLOW OVER THE CONUS. A LONG BAND OF CLOUD COVER WAS EVIDENT OVER THE ROCKIES AHEAD OF A SHORT WAVE TROUGH. LOW CLOUDS AND FOG WERE MOVING NORTH OVER THE TRI-STATE AREA DUE TO INCREASED MOISTURE ADVECTION FROM THE LOW LEVEL JET. LATEST OBSERVATIONS SHOW VISIBILITIES UNDER A MILE BEING REPORTED SPORADICALLY UNDER THE LOW CLOUDS. TODAY EXPECT THE FOG AND LOW CLOUDS TO PROGRESS NORTHWARD ACROSS THE ENTIRE AREA. THE WORST OF THE FOG WILL BE EAST OF THE COLORADO BORDER...WITH THE LOWEST VISIBILITIES OCCURRING DURING THE FIRST HALF OF THE MORNING. DUE TO CLOUDS REMAINING OVER THE AREA THROUGH THE DAY...THE FOG MAY LINGER A BIT LONGER THAN NORMAL. LOCATIONS WHERE VISIBILITIES ARE UNDER A MILE WILL LIKELY HAVE A THIN GLAZE OF ICE DEVELOP ON EXPOSED SURFACES. OTHERWISE AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA TODAY. DUE TO THE WEAK LIFT AND MOST OF THE MOISTURE REMAINING ABOVE 700MB...DO NOT ANTICIPATE ANY PRECIPITATION OCCURRING DURING THE DAY. TONIGHT A SECOND UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE AREA...CLOSING OFF FROM THE REST OF THE UPPER LEVEL FLOW OVER THE NORTHEAST HALF OF THE AREA. THE MAJORITY OF THE VORTICITY WILL BE WITH THE FIRST SHORT WAVE TROUGH...AHEAD OF THIS SECOND ONE. THIS WILL LEAD TO LITTLE OR NO MID/UPPER LEVEL LIFT WITH THIS TROUGH AS IT MOVES THROUGH. HOWEVER WEAK LOW LEVEL FRONTOGENESIS...IN THE FIRST KILOMETER ABOVE GROUND WHERE THE ENVIRONMENT WILL BE SATURATED...WILL LEAD TO SOME SNOW DEVELOPING AFTER MIDNIGHT OVER THE NORTHEAST QUADRANT OF THE AREA. THIS AREA OF SNOWFALL WILL GRADUALLY MOVE EAST WITH THE PARENT TROUGH. MEANWHILE ANOTHER AREA OF LIFT/LOW LEVEL FRONTOGENESIS WILL DEVELOP OVER THE NORTHWEST QUADRANT OF THE AREA BEHIND THE CLOSED LOW. THE FRONTOGENESIS IN THIS PART OF THE AREA IS STRONGER THAN TO THE EAST AND THE WEAK LIFT WITH IT IS DEEPER. IN ADDITION THE HIGH-RESOLUTION MODELS ARE INDICATING A BETTER SHOT OF SNOW DEVELOPING THERE THAN OVER THE EAST. WITH THIS IN MIND WILL HAVE THE BETTER CHANCES FOR SNOWFALL OVER THE NORTHWEST PART OF THE AREA. A COLD FRONT WILL ALSO MOVE THROUGH THE AREA WITH THE SECOND UPPER LEVEL TROUGH AND AHEAD OF THE SNOWFALL. BEHIND THE FRONT WINDS WILL INCREASE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 237 AM MST WED JAN 20 2016 THURSDAY MORNING THE LIGHT SNOW WILL CONTINUE OVER BOTH THE NORTHEAST AND NORTHWEST QUADRANTS OF THE AREA...GRADUALLY MOVING EAST THROUGH THE MORNING. BY THE EARLY AFTERNOON THE WEAK LIFT WILL END CAUSING ANY LINGERING SNOW TO END AS WELL. TOTAL SNOWFALL FOR TONIGHT AND THURSDAY WILL BE LESS THAN AN INCH. IN ADDITION TO THE SNOW NORTH WINDS WILL BE WINDY...WITH GUSTS UP TO 40 MPH OVER THE WEST HALF OF THE AREA. TO THE EAST THE WINDS WILL NOT BE AS STRONG DUE TO A WEAKER LOW LEVEL JET OVERHEAD. THE WINDS WILL LEAD TO BLOWING SNOW WHICH MAY REDUCE VISIBILITIES SOME. THE BLOWING SNOW WILL END DURING THE AFTERNOON. BEHIND THE SNOW CLOUDS WILL BEGIN TO CLEAR AS DRIER AIR MOVES INTO THE AREA FROM THE WEST. THURSDAY NIGHT WINDS WILL QUICKLY DECLINE DURING THE EVENING. MEANWHILE CLOUDS WILL CONTINUE TO CLEAR FROM WEST TO EAST. WITH A COOLER AIR MASS IN PLACE TEMPERATURES WILL FALL INTO THE TEENS. THIS WILL LEAD TO WIND CHILLS IN THE SINGLE DIGITS BY SUNRISE. FRIDAY/FRIDAY NIGHT WILL BE UNEVENTFUL AS DRIER AIR REMAINS IN PLACE AS A LONG WAVE RIDGE MOVES OVERHEAD. TEMPERATURES WILL WARM TO NEAR NORMAL. SATURDAY...UPPER RIDGE AXIS MOVES OVER THE AREA DURING THE DAY AHEAD OF A BROAD UPPER TROUGH WHOSE AXIS MOVES ASHORE BY SUNSET. FLOW ALOFT SHIFTS TO THE SOUTHWEST AS A RESULT AND CONTINUES THROUGH THE NIGHT. SOME HIGH CLOUDINESS EXPECTED DURING THE DAY...DECREASING SOME OVERNIGHT. NO PRECIPITATION EXPECTED. AFTERNOON TEMPERATURES PEAK IN THE MID 40S TO MID 50S (EAST TO WEST) WITH OVERNIGHT LOWS IN THE LOW TO MID 20S. SUNDAY...LONG RANGE MODELS IN BETTER AGREEMENT (COMPARED TO 24 HOURS AGO) BRINGING BASE OF UPPER TROUGH INTO THE AREA BY DAYS END THEN INTO THE MIDWEST OVERNIGHT. COLD FRONT MOVES THROUGH AS WELL WITH NORTHERLY SURFACE WINDS. MODELS DISAGREE ON EXTENT OF COLD AIR WITH THE ECMWF SEVERAL DEGREES COLDER AT 850MB WHEN COMPARED TO THE GFS. CURRENT FORECAST HIGHS IN THE MID TO UPPER 40S WOULD FAVOR THE GFS SOLUTION. NORTH WINDS CONTINUE OVERNIGHT WITH LOW TEMPERATURES IN THE LOW TO MID 20S. AS FAR AS PRECIPITATION CHANCES...WILL KEEP SOME SLIGHT CHANCE POPS GOING FOR THE DAY...INCREASING JUST A BIT OVERNIGHT. MONDAY...SUNDAYS WEATHER SYSTEM MOVES AWAY FROM THE AREA BUT THE FORECAST AREA IS CAUGHT IN NORTHWEST FLOW ALOFT ALLOWING MORE WEATHER SYSTEMS TO MOVE INTO THE AREA. CURRENTLY HAVE A DRY FORECAST BUT WOULDNT BE SURPRISED IF WE HAVE SOME SPOTTY LIGHT PRECIP. MAY SEE BREEZY NORTHWEST WINDS DURING THE DAY AS WELL. AFTERNOON TEMPERATURES A BIT COOLER AND JUST BELOW NORMAL WITH UPPER 30S TO LOW 40S. LOOKING AT SOME DECREASING CLOUDINESS OVERNIGHT WITH LOW TEMPERATURES IN THE MID TEENS TO LOW 20S. TUESDAY...SUNSHINE RETURNS TO THE AREA AS HIGH AMPLITUDE RIDGE AXIS MOVES SLOWLY TOWARD THE AREA DURING THE DAY. RIDGE AXIS BREAKS DOWN PRETTY QUICKLY OVERNIGHT WITH SOME INCREASE IN HIGH CLOUDS EXPECTED. AFTERNOON TEMPERATURES WARM BACK INTO THE LOW TO MID 40S WITH OVERNIGHT LOWS AGAIN IN THE MID TEENS TO LOW 20S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1023 PM MST TUE JAN 19 2016 VFR CONDITIONS WILL CONTINUE BRIEFLY AT KGLD AND KMCK AND THEN DETERIORATE TO MVFR AND LOWER, ESPECIALLY AT KMCK. THE HRRR KEEPS KGLD AT VFR WHILE THE NAM BRINGS SOME LOWER CONDITIONS. CONDITIONS SHOULD IMPROVE RATHER EARLY WEDNESDAY MORNING EVEN AT KMCK. SOME MID LEVEL CLOUDS REMAIN IN RESPONSE TO THE NEXT SHORTWAVE THAT COMES THROUGH WEDNESDAY AFTERNOON. CLOUDS DECREASE BRIEFLY WEDNESDAY EVENING IN A BRIEF LULL BEFORE THE NEXT SHORTWAVE AFFECTS THE AREA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...JTL LONG TERM...99/JTL AVIATION...FS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1041 AM EST WED JAN 20 2016 .SYNOPSIS... A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS. P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES THIS AFTN BEFORE THICKER CLDNS ARRIVES. ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH. HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S. WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE LEANED TOWARD THE COOLER MET NUMBERS. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES. FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN. FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN. AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND THERMODYNAMIC PROFILES CHANGE. && .LONG TERM /SATURDAY THROUGH TUESDAY/... LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S BY MON. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID AFTN TODAY. BUT...CLOUDS WILL INCREASE AND LWR QUICKLY...AS AN UPR LEVEL SYSTEM MOVES TOWARDS THE REGION. THAT UPR LEVEL SYSTEM WILL THEN CROSS THE REGION LATE THIS AFTN INTO EARLY TNGT...BRINGING A CHC FOR SOME LIGHT SNOW. MAINLY VFR CIGS ARE STILL EXPECTED AS THE LIGHT SNOW MOVES THRU. HOWEVER...MVFR CIGS WILL BE POSSIBLE...ESPLY AT RIC/SBY/PHF. NW WINDS EARLY TODAY...WILL SHIFT TO THE W THEN SW LATE THIS MORNG INTO EARLY TNGT...THEN BACK AGAIN TO THE NW OVRNGT TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES WILL PASS OVER THE AREA ON THU. A STRONG WINTER STORM WILL THEN AFFECT THE REGION LATE THU NGT INTO THE WEEKEND. && .MARINE... SCA CONDITIONS WILL CONTINUE UNTIL 10 AM THIS MORNG OVR ALL WTRS EXCEPT THE RIVERS...DUE TO RATHER STRONG NW WINDS STILL OCCURRING AS HI PRES BLDS JUST TO THE W OF THE WTRS. THE HI WILL BLD RIGHT OVR THE WTRS EARLY THIS AFTN...THEN WEAKEN AS AN UPR LEVEL SYSTEM SLIDES ACRS THE AREA AND OFF THE CST LATE THIS AFTN INTO EARLY TNGT. WINDS WILL BECOME WSW THIS AFTN THRU EARLY TNGT...THEN BECOME NW AGAIN LATE TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES BLDS INTO AND OVR THE AREA DURING THU. ATTENTION THEN TURNS TO A POTENT STORM SYSTEM SET TO IMPACT THE REGION FRI INTO SUN. INCREASINGLY POOR BOATING CONDITIONS ANTICIPATED BY LATER FRI THRU THE WEEKEND. NNW WINDS VEER AROUND TO THE NNE EARLY FRI...THEN INCREASE FRI AFTN/EVENG...AS LO PRES LIFTS ALONG THE SE CST AND HI PRES BLDS INTO CANADA. THE SFC LOW LIFTS OFF THE MID-ATLC CST FRI NIGHT INTO SAT...LIFTING AWAY FM THE CST SAT THRU SUN. STRONG SCA WINDS EXPECTED LATER FRI INTO SUN...WITH GALE FORCE WINDS POSSIBLE OVR THE CSTL WTRS AND CHES BAY LATE FRI NGT INTO SUN...AS FLO TURNS FM NE TO NNW. SEAS WILL ALSO BLD QUICKLY REACHING AS HIGH AS 8-12+ FT SAT. && .TIDES/COASTAL FLOODING... ISSUED LOW WATER ADVISORY FOR ALL MARINE ZNS EXCEPT THE RIVERS...CURRITUCK SND...AND NC CSTL WTRS FM 9 AM THIS MORNG UNTIL 2 PM...DUE TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN LOWER LOW WATER. TIDAL ANOMALIES ARE FORECAST TO REACH 1.5 TO 2.0 FEET LATE FRI INTO SAT...AS LO PRES IMPACTS THE REGION. COMBINATION OF STRONG ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES REACHING MHHW WILL PUSH CSTL AREAS OF THE ERN SHORE TOWARD MINOR FLOODING THRESHOLDS. STRONG NW WINDS BEHIND THE DEPARTING SYSTEM WILL POTENTIALLY FAVOR MINOR FLOODING OF THE CHESAPEAKE BAY SIDE OF THE LOWER EASTERN SHORE. WITH GALE CONDITIONS POSSIBLE LATE FRI NGT INTO SAT AND SEAS BUILDING TO 5 TO 12 FT...BEACH EROSION AND GENERAL SHORELINE EROSION IS EXPECTED ESPECIALLY ALONG THE LOWER BAY AND PORTIONS OF THE CST. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...LOW WATER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR ANZ630>632-634-650-652-654-656. && $$ SYNOPSIS...AJZ NEAR TERM...ALB/ESS SHORT TERM...ESS LONG TERM...MAS AVIATION...TMG MARINE...TMG TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1102 AM EST WED JAN 20 2016 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 315 AM EST WED JAN 20 2016 AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY. TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS WEEKEND OR EARLY NEXT WEEK. && .UPDATE... ISSUED AT 1102 AM EST WED JAN 20 2016 I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW. THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION. REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES WITH FLURRIES. UPDATE ISSUED AT 551 AM EST WED JAN 20 2016 CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY GIVEN CURRENT TRENDS: A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6 HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO WHITEHALL. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 315 AM EST WED JAN 20 2016 LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN INCH OF SNOW. THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN EFFECT UNTIL 18Z THIS AFTN. TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 315 AM EST WED JAN 20 2016 OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK. THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S. UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT THIS EARLY STAGE. THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW. RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE. FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR TRENDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1156 PM EST TUE JAN 19 2016 SNOW WILL BE ON THE INCREASE OVERNIGHT WITH WIDESPREAD IFR CONDITIONS DEVELOPING BY 12Z WEDNESDAY. EXPECT IFR AND SOME AREAS OF LIFR WEDNESDAY MORNING WITH CONDITIONS SLOWLY IMPROVING TO MVFR DURING THE AFTERNOON. WINDS WILL WEST SOUTHWEST AOB 10 KNOTS. && .MARINE... ISSUED AT 315 AM EST WED JAN 20 2016 WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF THE NEARSHORE WATERS. && .HYDROLOGY... ISSUED AT 324 PM EST TUE JAN 19 2016 WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING... HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ050- 056-064. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...HOVING AVIATION...OSTUNO HYDROLOGY...WDM MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
603 AM EST WED JAN 20 2016 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 315 AM EST WED JAN 20 2016 AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY. TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS WEEKEND OR EARLY NEXT WEEK. && .UPDATE... ISSUED AT 551 AM EST WED JAN 20 2016 CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY GIVEN CURRENT TRENDS: A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6 HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO WHITEHALL. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 315 AM EST WED JAN 20 2016 LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN INCH OF SNOW. THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN EFFECT UNTIL 18Z THIS AFTN. TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 315 AM EST WED JAN 20 2016 OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK. THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S. UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT THIS EARLY STAGE. THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW. RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE. FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR TRENDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1156 PM EST TUE JAN 19 2016 SNOW WILL BE ON THE INCREASE OVERNIGHT WITH WIDESPREAD IFR CONDITIONS DEVELOPING BY 12Z WEDNESDAY. EXPECT IFR AND SOME AREAS OF LIFR WEDNESDAY MORNING WITH CONDITIONS SLOWLY IMPROVING TO MVFR DURING THE AFTERNOON. WINDS WILL WEST SOUTHWEST AOB 10 KNOTS. && .MARINE... ISSUED AT 315 AM EST WED JAN 20 2016 WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF THE NEARSHORE WATERS. && .HYDROLOGY... ISSUED AT 324 PM EST TUE JAN 19 2016 WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING... HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ050- 056-064. LM...NONE. && $$ UPDATE...HOVING SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...HOVING AVIATION...OSTUNO HYDROLOGY...WDM MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1046 AM EST WED JAN 20 2016 .SYNOPSIS... A WEAK UPPER LEVEL DISTURBANCE WILL CROSS THE CAROLINAS TODAY. ANOTHER LOW IS EXPECTED TO DEVELOP TO OUR WEST ON THURSDAY AND SPREAD PRECIPITATION ACROSS THE AREA THURSDAY NIGHT AND FRIDAY AS IT MOVES ACROSS THE REGION. THE SYSTEM WILL EVENTUALLY MOVE OFF THE MID ATLANTIC COAST OVER THE WEEKEND WITH DRIER HIGH PRESSURE SPREADING BACK OVER THE REGION IN ITS WAKE ON SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM EST...EVEN VERY LIGHT RETURNS ON RADAR HAVE BEEN REMARKABLY EFFICIENT AT PRODUCING A SLIPPERY DUSTING OF SNOW DESPITE THE DRY SUB CLOUD AIR. BOTH THE LATEST RAP AND 12Z NAM ARE NOW PRESENTING MORE ISENTROPIC UPGLIDE THROUGH A NARROW WINDOW THIS AFTERNOON...AND WET BULB PROFILES SUPPORT MAINLY SNOW UNTIL MID LEVELS DRY OUT THIS EVENING. GIVEN THE UPTICK IN QPF AND ASSOCIATED COLD/SLIPPERY ROADWAYS IMPACT...HAVE EXPANDED THE ADVISORY INTO STEPHENS COUNTY IN NE GA...THE UPSTATE MOUNTAINS...AND THE NC FOOTHILLS AND NW PIEDMONT. WILL ALSO UPGRADE GRAHAM COUNTY TO A WARNING WITH 3 TO 5 INCH SNOW TOTALS QUITE WIDESPREAD AS THE HEAVIER RATES MOVES IN WITH THE REFLECTIVE BAND TO THE WEST. THE UPPER SUPPORT WITH THE PASSING WAVE AND THE LOWER LEVEL ISENTROPIC LIFT SHUT OFF QUICKLY TOWARD EVENING. MOISTURE LINGERS AT LOW LEVELS...BUT MID LEVELS DRY OUT TO WARRANT A POSSIBLE SWITCHOVER FROM WEST TO EAST OF LIGHT FREEZING RAIN OR FREEZING DRIZZLE. BLACK ICE CONDITIONS WILL REMAIN A PROBLEM OVERNIGHT IN ANY AREAS RECEIVING ACCUMULATING SNOW GIVEN MINS IN THE 20S AND LOWER 30S. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... AS OF 340 AM WEDNESDAY...LATEST IR SATELLITE IMAGES INDICATED THAT THE SYSTEM THAT WILL IMPACT THE REGION LATE THIS WEEK WAS OVER THE PACIFIC NORTHWEST. THE FORECAST WILL BE AIDED BY GENERALLY GOOD SHORT RANGE MODEL AGREEMENT...AND DETAILED TEMPERATURE FIELDS FROM THE NAM12. I WILL USE A BLEND OF THE SYNOPTIC FEATURES OF THE GFS AND ECMWF FROM THURSDAY THROUGH SATURDAY. HOWEVER...ON FRIDAY...I WILL BLEND IN LLVL THERMAL DETAILS FROM THE NAM12...BANKING ON THE BETTER HANDLING OF COLD AIR DAMMING. THURSDAY...0Z RUN OF THE GFS AND ECMWF HAVE TRENDED SLOWER WITH THE ONSET OF WARM FRONT ASSOCIATED PRECIP. THIS FORECAST PACKAGE WILL FEATURE SLOWER INCREASE OF POPS FRONT SW TO NE...DECREASING QPF. BY LATE THURSDAY AFTERNOON...I WILL FORECAST LIKELY POPS ACROSS THE UPPER SAVANNAH RIVER VALLEY TO THE EXTREME WESTERN NC MTNS...SCHC OVER THE NC PIEDMONT AND FOOTHILLS. HIGH TEMPERATURES WILL GENERALLY RANGE IN THE MID 40S. BY 12Z FRIDAY...THE CENTER OF A WELL ORGANIZED LOW PRESSURE SYSTEM IS FORECAST OVER NRN MS/AL...WITH GFS FASTER NEAR THE TN/AL/GA STATE INTERSECTION. IT IS IMPORTANT TO NOTE THAT THE SFC HIGH WILL LIKELY START TO RIDGE SW ACROSS THE MID ATLANTIC STATES AND ALONG THE EAST FACING SLOPES OF THE SOUTHERN APPALACHIANS. THE PATTERN SUPPORTS DEEP ISENTROPIC LIFT ALONG WITH IDEAL UPSLOPE FLOW. THE COMBINATION OF DEEP MOISTURE AND DEEP LLVL LIFT WILL SUPPORT NEAR 100 PERCENT BY THE PRE DAWN HOURS FRIDAY. COLD AIR DAMMING WILL SURGE ACROSS THE FOOTHILLS AND PIEDMONT...SUPPORTED BY GUSTY NE WINDS. FREEZING TEMPERATURES ARE EXPECTED TO SPREAD SW ACROSS THE EAST FACING SLOPES...UPPER FRENCH BROAD VALLEY...AND EAST ACROSS THE I-40 CORRIDOR. GENERALLY...H85 WAA WILL SUPPORT RAINFALL THURSDAY EVENING. HOWEVER...THE HEART OF THE CAD WILL ERODE THE WARM NOSE AND SHOULD YIELD AN IMPRESSIVE ROUND OF SLEET ACROSS THE NC FOOTHILLS DURING THE LATE NIGHT HOURS THURSDAY NIGHT. SURGING COLD AIR SHOULD PROVIDE COLD THERMAL PROFILES...SUPPORTING A PERIOD OF FOOTHILL SNOW DURING THE PRE DAWN HOURS FRI. AFTER SUNRISE FRIDAY...THE LOW CENTER IS FORECAST TO LIFT NE ACROSS NRN GA...PROVIDING A DEEPER WARM NOSE ACROSS THE WESTERN CAROLINAS AND NE GA. HOWEVER...THE BL ACROSS THE NC ZONES WILL MAINTAIN REINFORCING CAA. A CLASSIC FREEZING RAIN PROFILE DEVELOPS NORTH THE NC/SC LINE DURING THE EARLY DAYLIGHT HOURS. THE FREEZING RAIN LINE WILL LIFT NORTH ACROSS THE NRN FOOTHILLS AND NRN NC MTNS BY MID DAY. THE PEAK H5 Q-VECTOR CONVERGENCE WILL CROSS OVER THE FORECAST AREA ON FRI...PEAKING AROUND 18Z. THE ADDED FORCING SHOULD RESULT IN A PERIOD OF MODERATE FZRA ACROSS THE I-40 CORRIDOR FRIDAY AFTERNOON. BY 0Z SAT...DAMAGING FREEZING RAIN IS EXPECTED ACROSS THE UNIFOUR EAST ACROSS THE UPPER I-77 CORRIDOR...NORTH OF LAKE NORMAN. FRIDAY NIGHT...THE LOW CENTER WILL REACH THE OUTER BANKS OF NC AS THE CENTER OF A CLOSED H5 LOW TRACKS OVER THE SOUTHERN APPALACHIANS. GRADUALLY...H85 WINDS WILL INCREASE FROM THE NW...RESULTING IN CAA ACROSS THE REGION. A WINTRY MIX AND RAIN WILL TRANSITION TO SNOW FROM WEST TO EAST FRIDAY NIGHT. ACCUMULATING SNOWFALL SHOULD INCREASE FRIDAY EVENING...THEN REMAINING STEADY OVER THE TN BORDER COUNTIES THROUGH SAT. STORM TOTAL SNOWFALL IS FORECAST TO RANGE FROM NEARLY A FOOT OVER THE HIGHEST ELEVATIONS OF AVERY COUNTY...TO 5 TO 8 INCHES ACROSS THE BLUE RIDGE...WITH SEVERAL INCHES ACROSS THE I-40 CORRIDOR. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... AS OF 410 AM WEDNESDAY...SUNDAY AND MONDAY...N-S SFC HIGH PRESSURE WILL SLIDE EAST ACROSS THE REGION UNDER THE AXIS OF A PASSING H5 L/W RIDGE. CONDITIONS WILL REMAIN DRY WITH TEMPS RETURNING TO SEASONABLE VALUES. A COLD FRONT IS FORECAST TO PASS OVER THE MTNS MON NIGHT...PASSING SLOWLY EAST ON TUESDAY. THERMAL PROFILES WILL RESULT IN LIGHT RAIN TO SWITCH TO SNOW ACROSS THE MTNS AND NC FOOTHILLS EARLY TUESDAY MORNING. SHORTLY AFTER SUNRISE TUESDAY...PRECIP WILL FALL AS RAIN ACROSS THE REGION. HIGH TEMPERATURE ON TUESDAY IS FORECAST TO RANGE IN THE 40S ACROSS THE MTNS TO LOW TO MID 50S EAST. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... AT KCLT AND ELSEWHERE...LOWERING VFR CIGS WILL CONTINUE THROUGH THE AFTERNOON...WITH MVFR LIKELY UNDER ANY BETTER SNOW SHOWERS..STARTING AT KAVL FIRST. EXPECT THE SNOW POTENTIAL WINDOW TO START UP MOMENTARILY AT KAVL AND THEN SPREAD EAST THROUGH THE AFTN...REACHING KCLT MAINLY 20Z TO 00Z. THE WESTERLY FLOW ABOVE THE SFC IS NOT AS FAVORABLE FOR PRECIP ACROSS UPSTATE SC...SO A VCSH REMAINS MORE APPROPRIATE FOR KGSP/KGMU/KAND. CONDITIONS WILL IMPROVE AFTER 23Z. WIND SHOULD COME AROUND TO SW THIS EVENING...AND EVENTUALLY NW OR N AND LIGHT OVERNIGHT. OUTLOOK...THURSDAY MIGHT BE A BRIEF BREAK IN THE ACTION. A STRONGER STORM SYSTEM WILL ARRIVE FROM THE WEST THURSDAY NIGHT AND FRIDAY... WITH WIDESPREAD RESTRICTIONS AND WINTRY PRECIPITATION POSSIBLE... ESPECIALLY FROM KAVL TO KHKY. THE SYSTEM COULD LINGER INTO SATURDAY...WITH WINTRY PTYPES POSSIBLY PERSISTING AS WELL. CONFIDENCE TABLE... 15-21Z 21-03Z 03-09Z 09-12Z KCLT HIGH 100% HIGH 98% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 96% HIGH 100% HIGH 100% KAVL HIGH 98% MED 70% MED 64% MED 74% KHKY HIGH 100% MED 73% HIGH 96% HIGH 100% KGMU HIGH 100% HIGH 93% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 88% HIGH 94% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLET HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: WWW.WEATHER.GOV/GSP/AVIATION && .GSP WATCHES/WARNINGS/ADVISORIES... GA...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR GAZ010-017- 018. NC...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR NCZ033- 035>037-048>053-056-057-059-062>065-068-069-501>510. WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NCZ058. SC...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR SCZ001>003. && $$ SYNOPSIS...DEO NEAR TERM...HG/PM SHORT TERM...NED LONG TERM...NED AVIATION...HG/PM
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1045 AM MST WED JAN 20 2016 .UPDATE... ISSUED AT 929 AM MST WED JAN 20 2016 12Z NAM AND LATEST HRRR HAVE COME IN WITH HEAVIER SNOW OVER THE CENTRAL MOUNTAINS TODAY AND TONIGHT...WITH UP TO 8 INCHES OVER HIGHER WEST FACING SLOPES OF THE SAWATCH RANGE AND A FEW POCKETS OF 6 OVER THE NORTHERN LA GARITAS. WILL THUS HOIST A WINTER WEATHER ADVISORY FOR THESE AREAS FOR TODAY INTO THIS EVENING. OUTSIDE OF THE ADVISORY AREAS...HAVE BOOSTED POPS AND SNOW AMOUNTS SLIGHTLY AROUND LEADVILLE...WHILE KEEPING FORECAST FOR AREAS FARTHER EAST UNCHANGED. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM MST WED JAN 20 2016 ONE DISTURBANCE WILL BE MOVING ACRS THE AREA THIS MORNING...WITH ANOTHER ONE ENTERING WRN CO AROUND MIDDAY AND MOVING ACRS THE AREA THROUGH TONIGHT. THE FIRST DISTURBANCE WL BRING SOME SNOW TO THE CONTDVD THIS MORNING...WITH A LULL IN ACTIVITY BY LATE MORNING AND EARLY AFTERNOON. THEN AS THE NEXT DISTURBANCE APPROACHES THIS AFTERNOON AND THEN MOVES ACRS THE AREA TONIGHT...THE SNOW WL INCREASE AGAIN ALONG THE CONTDVD. SOME OF THE ERN MTNS COULD SEE SOME LIGHT SNOW THIS MORNING ASSOCIATED WITH THIS FIRST DISTURBANCE...BUT THE SERN PLAINS IS EXPECTED TO BE DRY. TONIGHT...AS THE NEXT DISTURBANCE MOVES ACRS THE AREA...THERE WL PROBABLY BE THE CHANCE FOR SOME LIGHT SNOW ACRS THE SAN LUIS VALLEY FOR A FEW HOURS...AND ACRS THE ERN MTNS. THE CHANCE FOR PCPN WL THEN SPREAD TO THE SERN PLAINS. OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NW TO SE ACRS THE FORECAST AREA AS THE DISTURBANCE MOVES SOUTHEASTWARD ACRS THE AREA. HOWEVER... FAVORABLE NWRLY FLOW WL PROBABLY KEEP SOME LIGHT SNOW GOING OVR THE CENTRAL MTNS. MOST OF THE MTNS AREA TONIGHT WL JUST SEE SOME LIGHT ACCUMULATIONS...HOWEVER THE CENTRAL MTNS WL PROBABLY SEE UP TO SIX INCHES OF ACCUMULATION...WITH THE HIGHEST AMOUNTS MAINLY BEING NORTH OF COTTONWOOD PASS. WITH THE FRONT EXPECTED TO HOLD OFF MOVING INTO THE SERN PLAINS UNTIL THIS EVENING...THE WESTERLY FLOW AND MIXING TODAY SHOULD WARM TEMPS INTO THE UPPER 40S TO LOWER 50S ACRS THE SERN PLAINS WHICH IS ABOVE AVERAGE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 425 AM MST WED JAN 20 2016 NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM WITH PRIMARY METEOROLOGICAL CONCERNS BEING TEMPERATURES...POPS AND GUSTY WINDS AT TIMES. INITIAL DISTURBANCE IS EXPECTED TO BE DEPARTING THE FORECAST DISTRICT THURSDAY...ALLOWING FOR ISOLATED SHOWER POTENTIAL OVER EASTERN SECTIONS AND THE CENTRAL MOUNTAINS...PRIMARILY DURING THE MORNING HOURS. IN ADDITION...GUSTY WINDS ARE ANTICIPATED OVER SEVERAL LOCATIONS FROM THURSDAY INTO THURSDAY NIGHT AS THE SYSTEM PULLS EAST OF THE CWA. A DRY UPPER RIDGING TO ZONAL/SOUTHWESTERLY UPPER PATTERN IS STILL EXPECTED TO DEVELOP OVER THE FORECAST DISTRICT FROM THURSDAY NIGHT INTO SATURDAY...ALLOWING FOR GENERALLY DRY AND WARMER CONDITIONS IN COMBINATION WITH GUSTY WINDS AT TIMES. NEXT UPPER DISTURBANCE IN COMBINATION WITH NORTH TO NORTHEASTERLY SURFACE SURGES ARE STILL EXPECTED TO IMPACT THE FORECAST DISTRICT FROM LATER THIS WEEKEND INTO EARLY NEXT WEEK ALLOWING FOR A RETURN OF COOLER CONDITIONS AND INCREASED PRECIPITATION CHANCES. AT THIS TIME...IT APPEARS THAT LOCATIONS SUCH AS THE I-25 CORRIDOR AND PORTIONS OF THE EASTERN PLAINS WILL HAVE THE HIGHEST POTENTIAL OF RECEIVING MEASURABLE PRECIPITATION DURING THE LATER MONDAY INTO TUESDAY TIME-FRAME. WARMEST TEMPERATURES DURING THE LONGER TERM SHOULD BE NOTED SATURDAY...WITH COOLEST READINGS EXPECTED THURSDAY AND THEN AGAIN BY NEXT MONDAY AND TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1037 AM MST WED JAN 20 2016 AT KALS...WEB CAMS SUGGEST BRIEF PERIOD OF FOG BEGINNING TO DISSIPATE ALREADY...AND WILL KEEP ONLY TEMPO IFR CONDITIONS 18Z- 19Z BEFORE CIGS/VIS BECOME VFR AGAIN. FOR THE AFTERNOON AND TONIGHT...PREVAILING CONDITIONS WILL BE VFR...BUT WILL CARRY A VCSH MENTION INTO THE EVENING AS A FEW -SHSN MOVE OFF THE HIGHER TERRAIN AND ACROSS THE VALLEY. AT KCOS AND KPUB...VFR CONDITIONS TODAY AND TONIGHT...BUT WILL CARRY A VCSH MENTION INTO THE EVENING AS A FEW -SHSN DEVELOP AS UPPER TROUGH MOVES OVER THE REGION. MOUNTAINS...ESPECIALLY ALONG THE CONTINENTAL DIVIDE...WILL SEE A PERIOD OF IFR/LIFR CIGS/VIS IN SNOW DEVELOP THIS AFTERNOON AND CONTINUE THROUGH THE EVENING. SOME SLOW CLEARING THEN AFTER 06Z- 08Z...ESPECIALLY FROM KMYP SOUTHWARD. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ058- 060-066. && $$ UPDATE...PETERSEN AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
936 AM MST WED JAN 20 2016 .UPDATE... ISSUED AT 929 AM MST WED JAN 20 2016 12Z NAM AND LATEST HRRR HAVE COME IN WITH HEAVIER SNOW OVER THE CENTRAL MOUNTAINS TODAY AND TONIGHT...WITH UP TO 8 INCHES OVER HIGHER WEST FACING SLOPES OF THE SAWATCH RANGE AND A FEW POCKETS OF 6 OVER THE NORTHERN LA GARITAS. WILL THUS HOIST A WINTER WEATHER ADVISORY FOR THESE AREAS FOR TODAY INTO THIS EVENING. OUTSIDE OF THE ADVISORY AREAS...HAVE BOOSTED POPS AND SNOW AMOUNTS SLIGHTLY AROUND LEADVILLE...WHILE KEEPING FORECAST FOR AREAS FARTHER EAST UNCHANGED. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM MST WED JAN 20 2016 ONE DISTURBANCE WILL BE MOVING ACRS THE AREA THIS MORNING...WITH ANOTHER ONE ENTERING WRN CO AROUND MIDDAY AND MOVING ACRS THE AREA THROUGH TONIGHT. THE FIRST DISTURBANCE WL BRING SOME SNOW TO THE CONTDVD THIS MORNING...WITH A LULL IN ACTIVITY BY LATE MORNING AND EARLY AFTERNOON. THEN AS THE NEXT DISTURBANCE APPROACHES THIS AFTERNOON AND THEN MOVES ACRS THE AREA TONIGHT...THE SNOW WL INCREASE AGAIN ALONG THE CONTDVD. SOME OF THE ERN MTNS COULD SEE SOME LIGHT SNOW THIS MORNING ASSOCIATED WITH THIS FIRST DISTURBANCE...BUT THE SERN PLAINS IS EXPECTED TO BE DRY. TONIGHT...AS THE NEXT DISTURBANCE MOVES ACRS THE AREA...THERE WL PROBABLY BE THE CHANCE FOR SOME LIGHT SNOW ACRS THE SAN LUIS VALLEY FOR A FEW HOURS...AND ACRS THE ERN MTNS. THE CHANCE FOR PCPN WL THEN SPREAD TO THE SERN PLAINS. OVERNIGHT...PCPN CHANCES ARE EXPECTED TO DECREASE OR END FROM NW TO SE ACRS THE FORECAST AREA AS THE DISTURBANCE MOVES SOUTHEASTWARD ACRS THE AREA. HOWEVER... FAVORABLE NWRLY FLOW WL PROBABLY KEEP SOME LIGHT SNOW GOING OVR THE CENTRAL MTNS. MOST OF THE MTNS AREA TONIGHT WL JUST SEE SOME LIGHT ACCUMULATIONS...HOWEVER THE CENTRAL MTNS WL PROBABLY SEE UP TO SIX INCHES OF ACCUMULATION...WITH THE HIGHEST AMOUNTS MAINLY BEING NORTH OF COTTONWOOD PASS. WITH THE FRONT EXPECTED TO HOLD OFF MOVING INTO THE SERN PLAINS UNTIL THIS EVENING...THE WESTERLY FLOW AND MIXING TODAY SHOULD WARM TEMPS INTO THE UPPER 40S TO LOWER 50S ACRS THE SERN PLAINS WHICH IS ABOVE AVERAGE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 425 AM MST WED JAN 20 2016 NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM WITH PRIMARY METEOROLOGICAL CONCERNS BEING TEMPERATURES...POPS AND GUSTY WINDS AT TIMES. INITIAL DISTURBANCE IS EXPECTED TO BE DEPARTING THE FORECAST DISTRICT THURSDAY...ALLOWING FOR ISOLATED SHOWER POTENTIAL OVER EASTERN SECTIONS AND THE CENTRAL MOUNTAINS...PRIMARILY DURING THE MORNING HOURS. IN ADDITION...GUSTY WINDS ARE ANTICIPATED OVER SEVERAL LOCATIONS FROM THURSDAY INTO THURSDAY NIGHT AS THE SYSTEM PULLS EAST OF THE CWA. A DRY UPPER RIDGING TO ZONAL/SOUTHWESTERLY UPPER PATTERN IS STILL EXPECTED TO DEVELOP OVER THE FORECAST DISTRICT FROM THURSDAY NIGHT INTO SATURDAY...ALLOWING FOR GENERALLY DRY AND WARMER CONDITIONS IN COMBINATION WITH GUSTY WINDS AT TIMES. NEXT UPPER DISTURBANCE IN COMBINATION WITH NORTH TO NORTHEASTERLY SURFACE SURGES ARE STILL EXPECTED TO IMPACT THE FORECAST DISTRICT FROM LATER THIS WEEKEND INTO EARLY NEXT WEEK ALLOWING FOR A RETURN OF COOLER CONDITIONS AND INCREASED PRECIPITATION CHANCES. AT THIS TIME...IT APPEARS THAT LOCATIONS SUCH AS THE I-25 CORRIDOR AND PORTIONS OF THE EASTERN PLAINS WILL HAVE THE HIGHEST POTENTIAL OF RECEIVING MEASURABLE PRECIPITATION DURING THE LATER MONDAY INTO TUESDAY TIME-FRAME. WARMEST TEMPERATURES DURING THE LONGER TERM SHOULD BE NOTED SATURDAY...WITH COOLEST READINGS EXPECTED THURSDAY AND THEN AGAIN BY NEXT MONDAY AND TUESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 425 AM MST WED JAN 20 2016 KCOS AND KPUB SHOULD SEE VFR CONDITIONS TODAY WITH THE POTENTIAL FOR SOME GUSTY WEST TO NW WINDS THIS AFTERNOON. AS A FRONT MOVES THRU THESE LOCATIONS THIS EVENING...THE WINDS WL BE NW TO N AND GUSTY. THE COULD BE A FEW SNOW SHOWERS IN THE VCNTY OF THE TERMINALS THIS EVENING WHICH COULD BRING LOWER CIGS FOR A BRIEF PERIOD. KALS SHOULD HAVE VFR CONDITIONS THRU THE PERIOD...ALTHOUGH THERE WL BE THE POTENTIAL FOR SOME SNOW SHOWERS IN THE VCNTY THIS EVENING WHICH COULD BRING A BRIEF PERIOD OF LOWER CIGS. AS A DISTURBANCE PASSES THE ARE TONIGHT...WINDS ARE EXPECTED TO BECOME NORTHWESTERLY AND COULD BE BREEZY FOR A FEW HOURS. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ058- 060-066. && $$ UPDATE...PETERSEN
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
547 PM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... UPDATE...RADAR...SURFACE OBS...AND PUBLIC REPORTS INDICATE AREA OF LIGHT RAIN AND LIGHT SLEET MIX INTO THE CSRA AND CENTRAL MIDLANDS. NO ACCUMULATION EXPECTED AS SURFACE TEMPS WILL REMAIN WELL ABOVE FREEZING. LATEST HIGH RESOLUTION MODELS SUGGEST THE PRECIPITATION AREA WILL DECREASE IN COVERAGE AS IT MOVES EAST ACROSS OUR FORECAST AREA (FA) THROUGH EARLY THIS EVENING. FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT. OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40 SOUTH. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/... UPDATED...THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN LATE THURSDAY NIGHT THROUGH FRIDAY. WILL POST WINTER STORM WATCH... THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER- MID MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH. PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH PRECIPITATION. THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE. COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN SOUTH CAROLINA BY 00Z SATURDAY. RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT FRIDAY AFTERNOON. THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR LANCASTER/CHESTERFIELD IF NEEDED. FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY NIGHT. THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH 500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE LIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... A LIGHT RAIN AND SLEET MIXTURE EXPECTED IN THE NEAR TERM. NO SLEET ACCUMULATION DUE TO TEMPERATURES WELL ABOVE FREEZING. CLOUD BASES ARE ABOVE VFR LEVEL. PRECIPITATION EXPECTED TO DIMINISH EARLY THIS EVENING...WITH MID LEVEL CLOUDINESS REMAINING IN PLACE. LIGHT WINDS. LIGHT RAIN POSSIBLE THURSDAY...BUT CLOUD BASES ARE EXPECTED TO REMAIN ABOVE VFR LEVEL THRU 18Z. EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO MVFR CONDITIONS THURSDAY NIGHT THROUGH SATURDAY. BREEZY CONDITIONS POSSIBLE SATURDAY/SATURDAY NIGHT. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY EVENING FOR SCZ015-016. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
532 PM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... UPDATE...RADAR AND SURFACE OBS INDICATE AREA OF LIGHT RAIN AND LIGHT SNOW ACROSS THE UPSTATE SC AND N GA...MOVING EAST. LATEST HIGH RESOLUTION MODELS SUGGEST THE PRECIPITATION AREA WILL DECREASE IN COVERAGE AS IT MOVES EAST INTO OUR FORECAST AREA (FA) LATE THIS AFTERNOON AND EARLY EVENING. HOWEVER...CHANCE OF PRECIPITATION IN THE VERY NEAR TERM APPEARS VERY HIGH AT LEAST ACROSS THE NORTHERN FA. LATEST GUIDANCE AND TRENDS SUGGEST THE NORTHERN FA COULD SEE A MIX OF LIGHT RAIN...LIGHT SNOW...OR SLEET IN THE NEAR TERM. NO ACCUMULATION EXPECTED AS SURFACE TEMPS WILL REMAIN WELL ABOVE FREEZING. FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT. OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40 SOUTH. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/... ...UPDATED...THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT IMPACTS INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR FREEZING RAIN LATE THURSDAY NIGHT THROUGH FRIDAY. WILL POST WINTER STORM WATCH... THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER- MID MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH. PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH PRECIPITATION. THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE. COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN SOUTH CAROLINA BY 00Z SATURDAY. RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT FRIDAY AFTERNOON. THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR LANCASTER/CHESTERFIELD IF NEEDED. FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY NIGHT. THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH 500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE LIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER SUNRISE THURSDAY MORNING. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY EVENING FOR SCZ015-016. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
406 PM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... UPDATE...RADAR AND SURFACE OBS INDICATE AREA OF LIGHT RAIN AND LIGHT SNOW ACROSS THE UPSTATE SC AND N GA...MOVING EAST. LATEST HIGH RESOLUTION MODELS SUGGEST THE PRECIPITATION AREA WILL DECREASE IN COVERAGE AS IT MOVES EAST INTO OUR FORECAST AREA (FA) LATE THIS AFTERNOON AND EARLY EVENING. HOWEVER...CHANCE OF PRECIPITATION IN THE VERY NEAR TERM APPEARS VERY HIGH AT LEAST ACROSS THE NORTHERN FA. LATEST GUIDANCE AND TRENDS SUGGEST THE NORTHERN FA COULD SEE A MIX OF LIGHT RAIN...LIGHT SNOW...OR SLEET IN THE NEAR TERM. NO ACCUMULATION EXPECTED AS SURFACE TEMPS WILL REMAIN WELL ABOVE FREEZING. FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT. OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40 SOUTH. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/... THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER-MID MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH. PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH PRECIPITATION. THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE. COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN SOUTH CAROLINA BY 00Z SATURDAY. RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT FRIDAY AFTERNOON. THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR LANCASTER/CHESTERFIELD IF NEEDED. FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY NIGHT. THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH 500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE LIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER SUNRISE THURSDAY MORNING. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
307 PM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... REST OF THE AFTERNOON...THE SURFACE RIDGE IS CURRENTLY CENTERED OVER THE COASTAL PLAIN OF THE CAROLINAS. THE RIDGE WILL HELP LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO THE FORECAST AREA. THE LATEST HRRR INDICATES PRECIPITATION DIMINISHING AS IT MOVES INTO THE AREA FROM THE WEST THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20 PERCENT SOUTH LATER THIS AFTERNOON. THE TOP-DOWN METHOD RUN ON BOTH THE NAM AND GFS NOW INDICATING PATCHES OF LIGHT RAIN ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA WITH LOW CHANCE POPS. GIVEN THE POTENTIAL FOR EVAPORATIVE COOLING WITH THE CURRENT LOW DEWPOINTS...CANNOT RULE OUT A BRIEF MIX OF SOME SNOW WITH THE RAIN ACROSS PORTIONS IN THE EXTREME NORTH LATER THIS AFTERNOON...BUT NO ACCUMULATIONS ARE EXPECTED. FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT. OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40 SOUTH. && .SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/... THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER-MID MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH. PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH PRECIPITATION. THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE. COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN SOUTH CAROLINA BY 00Z SATURDAY. RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT FRIDAY AFTERNOON. THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR LANCASTER/CHESTERFIELD IF NEEDED. FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY NIGHT. THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH 500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE LIGHT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER SUNRISE THURSDAY MORNING. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
200 PM EST WED JAN 20 2016 .SYNOPSIS... THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... REST OF THE AFTERNOON...THE SURFACE RIDGE IS CURRENTLY CENTERED OVER THE COASTAL PLAIN OF THE CAROLINAS. THE RIDGE WILL HELP LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO THE FORECAST AREA. THE LATEST HRRR INDICATES PRECIPITATION DIMINISHING AS IT MOVES INTO THE AREA FROM THE WEST THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20 PERCENT SOUTH LATER THIS AFTERNOON. THE TOP-DOWN METHOD RUN ON BOTH THE NAM AND GFS NOW INDICATING PATCHES OF LIGHT RAIN ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA WITH LOW CHANCE POPS. GIVEN THE POTENTIAL FOR EVAPORATIVE COOLING WITH THE CURRENT LOW DEWPOINTS...CANNOT RULE OUT A BRIEF MIX OF SOME SNOW WITH THE RAIN ACROSS PORTIONS IN THE EXTREME NORTH LATER THIS AFTERNOON...BUT NO ACCUMULATIONS ARE EXPECTED. FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT. OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40 SOUTH. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW PRESSURE SYSTEM LIFTS NORTHEAST. MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE 1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS REMAINS A LOW CONFIDENCE FORECAST. WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH. && .LONG TERM /FRIDAY THROUGH TUESDAY/... MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF. THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY NIGHT. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER SUNRISE THURSDAY MORNING. EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH SATURDAY. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. && $$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
104 PM EST WED JAN 20 2016 .PREV DISCUSSION... /ISSUED 1058 AM EST WED JAN 20 2016/ .UPDATE... IMPRESSIVE BAND OF HEAVIER PRECIP IMPINGING INTO NW CWA WITH SOME LIGHT MORE ISOLATED RETURNS AHEAD OF ASSOCIATED DISTURBANCE. SO FAR HAVE HAD SOME REPORTS OF FZRA AND SLEET BUT MAINLY IN FAR NORTH AND MAIN CONCERN OF IMPACTFUL ACCUMULATIONS WILL BE WITH APPROACHING BAND AS EVAP COOLING MECHANISM HAS SHOWN SOME SFC TEMP DROPS OF 2-3 DEG. GIVEN THE STILL LOW DWPTS ACROSS THE FAR NORTHERN TIER WITH VALUES STILL IN UPPER TEENS TO LOW 20S AT SOME SPOTS...COULD SEE SOME ISOLATED HIGHER ICE ACCUMULATIONS AROUND 0.25 INCHES. ALSO THE HRRR SO FAR LOOKS TO HAVE DECENT HOLD ON TRENDS WITH P-TYPE AND HAVE ADJUSTED POPS AND WINTER GRIDS ACCORDINGLY. HRRR PROGGED WETBULB TEMPS KEEP THE NE HIGHER ELEVATIONS AROUND 30 DEG THROUGH THE AFTERNOON ALONG WITH A TRANSITION FROM INITIAL MIXED P-TYPE TO PRIMARILY SNOW SO HAVE INCREASED THE LOWER BOUND SNOW AMOUNTS TO NEAR HALF AN INCH SLIGHTLY FARTHER SOUTHEAST TO NEAR GAINESVILLE AND EASTWARD. AS FAR AS NEAR THE METRO...OVERNIGHT TEMPS WERE THANKFULLY ABOUT 4 DEGREES WARMER THAN FCST SO TRENDS HAVE BEEN TO RISE TO 34-36 DEGREES FROM THE WEST. ALL IN ALL HAVE NOT ADJUSTED ANY EXTENT OR TIMING TO THE CURRENT ADVISORY AND WARNING AREAS. PREVIOUS DISCUSSION FOLLOWS... BAKER && PREV DISCUSSION... /ISSUED 652 AM EST WED JAN 20 2016/ PREV DISCUSSION... /ISSUED 437 AM EST WED JAN 20 2016/ .SHORT TERM /TODAY THROUGH THURSDAY/... SHORT TERM FORECAST CONTINUES TO BE A CHALLENGE WITH IMPACTFUL WINTRY PRECIPITATION EXPECTED ACROSS NORTH GEORGIA. UPPER LEVEL DISTURBANCE WILL INTERACT WITH COLD AND DRY CONDITIONS ACROSS THE AREA TO PRODUCE A WINTRY MIX OVER PORTIONS OF NORTH GEORGIA. ALTHOUGH MODELS HAVE SLOWED THE ONSET TIMING SLIGHTLY BY AN HOUR OR SO...CONSENSUS IS THAT PRECIPITATION WILL BEGIN AS SNOW THIS MORNING...THEN TRANSITION TO FREEZING RAIN/SLEET AND THEN TRANSITION TO ALL SNOW IN THE NE MOUNTAINS BY THE AFTERNOON. ACCUMULATING WINTRY MIX IS EXPECTED AS FAR SOUTH AS PORTIONS OF THE NORTHERN ATLANTA SUBURBS...BUT STILL COULD SEE SOME NON-ACCUMULATING MIX AS FAR SOUTH AS I-20. ALREADY SEEING SOME LIGHT RETURNS ON RADAR ACROSS AL/NORTHERN GEORGIA...BUT SO FAR NOTHING REACHING THE GROUND. MODELS CONTINUE TO SUGGEST THIS TO BE AN OVERALL LOW QPF EVENT...WITH LIQUID EQUIVALENT ONLY A QUARTER INCH OR LESS. WPC WWD GUIDANCE HAS BACKED OFF SOMEWHAT ON SNOWFALL TOTALS...BUT HAS SPREAD THE ACCUMULATING FREEZING RAIN AMOUNTS FARTHER SOUTH. GIVEN THE TIMING OF THE PRECIPITATION ONSET AND THE EXPECTED WARMING TEMPERATURES /PARTICULARLY ACROSS THE METRO AREA/ HAVE OPTED NOT TO DEVIATE TOO FAR FROM THE PREVIOUS SNOW/ICE AMOUNTS PREVIOUSLY FORECAST...A LITTLE MORE CONSERVATIVE IN AREAL COVERAGE THAN THE WWD ICE GRID. THE WINTER STORM WARNING AND THE WINTER WEATHER ADVISORY CONTINUE WITH NO CHANGES MADE TO THE TIMING OR AREA. STILL ANTICIPATE UP TO 2- 2.5 INCHES OF SNOW IN THE WSW /PARTICULARLY IN THE NE GA MOUNTAINS/ AND UP TO A TENTH OF AN INCH OF ICE. IN THE ADVISORY AREA UP TO 1 INCH OF SNOW AND A TENTH OF AN INCH OF ICE CAN BE EXPECTED. WITH COLD ANTECEDENT CONDITIONS...IMPACTS ARE EXPECTED AT ONSET OF THE PRECIPITATION. HAVE ALSO CONTINUED THE SPECIAL WEATHER STATEMENT FOR SEVERAL COUNTIES JUST SOUTH OF THE ADVISORY AREA TO INDICATE POTENTIAL FOR WINTRY PRECIPITATION MIXED WITH RAIN. THERE REMAINS SEVERAL UNCERTAINTIES WITH THE FORECAST THAT WILL NEED TO BE MONITORED AS THE EVENT UNFOLDS. THE WEAKENING RIDGE AND EROSION OF THE ASSOCIATED LOW LEVEL INVERSION WILL PLAY A KEY ROLE IN DURATION OF WINTER PRECIP. THERMODYNAMIC TRENDS WILL STILL NEED TO BE WATCHED FOR WETBULBING/EVAPORATIVE COOLING EFFECTS AND IF IT DELAYS THE TRANSITION TO OTHER P-TYPES. LINGERING FREEZING TEMPERATURES INTO THE OVERNIGHT HOURS COULD ALLOW FROZEN PRECIP TO CONTINUE AND INCREASE BLACK ICE THREAT. STAY TUNED AS THE FORECAST CONTINUES TO EVOLVE AS THE EVENT UNFOLDS. ALTHOUGH THE PRECIPITATION POTENTIAL DIMINISHES SOMEWHAT OVERNIGHT...ALL RAIN WILL RETURN TO THE AREA THURSDAY AND INTO THE INITIAL EXTENDED FORECAST PERIODS. ANTICIPATE THAT BY MID MORNING THURSDAY ALL OF NORTH AND CENTRAL GEORGIA SHOULD BE SEEING ABOVE- FREEZING TEMPERATURES. 31 && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... SOUTHERN STREAM LOW MOVING INTO THE LOWER MS VALLEY AT THE START OF THE PERIOD...TRACKING THROUGH THE TN VALLEY AND THEN OFF THE MID ATLANTIC COAST BY SATURDAY MORNING. EXPECTING ALL LIQUID PRECIP UNTIL FRIDAY NIGHT AS WRAP AROUND MOISTURE SPREADS INTO THE FORECAST AREA. PARTIAL THICKNESS VALUES WOULD SUPPORT SNOW FOR THE FAR NORTH AND A MIX OF RAIN AND SNOW FOR THE REMAINDER OF NORTH. FOR NOW...HAVE KEPT LIGHT ACCUMULATIONS CONFINED TO THE FAR NORTH SINCE ACTUAL QPF IS STILL QUESTIONABLE. SOME LIGHT WRAP AROUND SNOW IS POSSIBLE SATURDAY FOR THE EXTREME NORTH AS THE LOW CONTINUES TO MOVE NORTHEAST. SUNDAY LOOKS DRY BUT THE NEXT LOW IS MOVING INTO THE MID MS VALLEY BY MONDAY...BRINGING MOISTURE BACK INTO THE FORECAST AREA. PRECIPITATION SHOULD SPREAD ACROSS NORTH AND CENTRAL GEORGIA MONDAY AND TUESDAY. LOOKING FOR ALL RAIN MONDAY AND TUESDAY...HOWEVER LEADING INTO TUESDAY NIGHT THERE IS ANOTHER CHANCE FOR SOME FREEZING OR FROZEN PRECIP ACROSS FAR NORTH GEORGIA. 41 && .AVIATION... 18Z UPDATE... INITIAL VFR CONDITIONS SHOULD DEGRADE TO MVFR CIGS BEHIND AREA OF PRECIP PUSHING EASTWARD THEN IFR CIGS WITH VSBYS IN MVFR/IFR RANGE AFTER ABOUT 08Z TONIGHT WITH LITTLE TO NO IMPROVEMENT FOR THURSDAY AFTERNOON. COULD HAVE LINGERING -DZ OVERNIGHT THEN BETTER CHANCE FOR WIDESPREAD -RA OR -SHRA AGAIN THURSDAY. ANY WINTRY PRECIP POTENTIAL SHOULD STAY NORTH OF THE TAF SITES INTO THIS EVENING. WINDS COULD SEE SSW SHIFT IN INITIAL 3-4 HRS THEN BACK TO SE/E THRU REST OF PERIOD. MAGNITUDES 7-8 KTS BECOMING LIGHT TO CALM OVERNIGHT AND UNDER 7 KTS FOR THURSDAY. //ATL CONFIDENCE...18Z UPDATE... MEDIUM ON ALL ELEMENTS. BAKER && .PRELIMINARY POINT TEMPS/POPS... ATHENS 41 33 43 38 / 70 70 70 90 ATLANTA 42 37 47 42 / 80 70 70 90 BLAIRSVILLE 35 31 45 36 / 90 40 70 90 CARTERSVILLE 38 33 46 40 / 90 50 70 90 COLUMBUS 50 43 59 49 / 60 70 60 90 GAINESVILLE 35 32 42 37 / 90 60 70 90 MACON 50 40 54 45 / 40 50 50 70 ROME 37 34 46 41 / 90 30 80 90 PEACHTREE CITY 44 35 49 43 / 70 70 70 90 VIDALIA 54 41 57 47 / 20 20 30 50 && .FFC WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR THE FOLLOWING ZONES: CATOOSA...CHATTOOGA...DADE...DAWSON...FANNIN...GILMER... GORDON...LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...WALKER... WHITE...WHITFIELD. WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR THE FOLLOWING ZONES: BANKS...BARTOW...CHEROKEE...FLOYD...FORSYTH... HALL. && $$ SHORT TERM...31/BAKER LONG TERM....41 AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
133 PM CST WED JAN 20 2016 .UPDATE... 1051 AM CST FOR MORNING UPDATE... SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22 WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE WINDY/COLD OF THE PAST FEW DAYS. RATZER && .SHORT TERM... 313 AM CST THROUGH THURSDAY... PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY 12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW TEMPS. IZZI && .LONG TERM... 133 PM CST THURSDAY NIGHT THROUGH WEDNESDAY... MAIN CONCERN FOR THE LONGER TERM FORECAST PERIOD REMAINS THE CHANCES FOR LAKE EFFECT SNOW FRIDAY THROUGH FRIDAY NIGHT. IN THE MEAN TIME...THURSDAY NIGHT SHOULD START OUT THE LONG TERM FORECAST PERIOD RELATIVELY QUIET AS THE REGION WILL BE BETWEEN A LARGE AREA OF HIGH PRESSURE EXTENDING FROM THE NORTHERN PLAINS THROUGH THE GREAT LAKES AND A DEEPENING LOW PRESSURE SYSTEM MOVES THROUGH THE LOWER MISSISSIPPI VALLEY. WINDS WILL BEGIN TO SET UP NELY...LEADING INTO THE PERIOD OF LAKE EFFECT SNOW EXPECTED FOR FRIDAY. BY MIDDAY FRIDAY...THE HIGH WILL EXTEND FROM THE UPPER GREAT LAKES THROUGH THE SOUTH HIGH PLAINS WHILE LOW PRESSURE DEEPENS OVER THE SERN CONUS. A RELATIVE WEAKNESS IN THE PRESSURE GRADIENT IS EXPECTED TO DEVELOP ACROSS LOWER MICHIGAN...LAKE MICHIGAN AND INTO NRN ILLINOIS. WHILE THE GENERAL PATTERN WILL BE CONDUCIVE FOR LAKE EFFECT SNOW FOR NERN IL...POSSIBLY EXTENDING INTO FAR NWRN INDIANA ARND GYY...THE GREATEST LAKE INDUCED INSTABILITY SHOULD BE DURG THE DAYTIME HOURS ON FRIDAY WHEN INVERSION HEIGHTS WILL BE ARND 5KFT AND SFC TO 850MB DELTA-T SHOULD BE ARND 13C UNDER NELY WINDS. WHILE THE LONGER TERM GUIDANCE MAY LACK THE RESOLUTION OF THE SHORT TERM GUIDANCE...THE GFS/ECMWF ALSO INDICATE A CONVERGENCE BAND OVER THE SWRN PORTION OF LAKE MICHIGAN...FURTHER AIDING CONFIDENCE IN AT LEAST SOME LAKE EFFECT SNOW ACCUMULATION. WEAK CONVERGENCE IS EXPECTED TO CONTINUE INTO FRIDAY NIGHT...BUT THE FOCUS SHOULD SHIFT A LITTLE NORTH INTO SERN WISCONSIN. ALSO...LOW LEVEL INVERSION HEIGHTS AND INSTABILITY SHOULD DIMINISH THROUGH THE NIGHT...PER LATEST MODEL SOUNDINGS...SO EXPECT THE LAKE EFFECT SNOW POTENTIAL TO END BY SATURDAY MORNING. GIVEN WEAK FORCING AND MARGINAL LOW LEVEL INSTABILITY ALONG WITH A PROGRESSIVE CONVERGENCE ZONE...SNOW ACCUMULATIONS SHOULD BE LIGHT...GENERALLY UNDER AN INCH. FOR THE REMAINDER OF THE WEEKEND...THE AREA OF HIGH PRESSURE SHOULD MOVE ACROSS THE REGION...SETTLING INTO THE OHIO VALLEY SUNDAY NIGHT. EXPECT AMPLE SUNSHINE AND HIGHS IN THE LOWER 30S FOR SATURDAY AND THE MIDDLE 30S SUNDAY. RELATIVELY MILD CONDITIONS SHOULD CONTINUE INTO MONDAY AS BROAD...DIFFUSE LOW PRESSURE ASSOCIATED WITH A SOUTHERN STREAM SHORTWAVE...REACHES THE MIDDLE MISSISSIPPI VALLEY...WITH A ZONE OF BROAD WARM/MOIST ADVECTION AHEAD OF THE WEAK LOW. THIS SYSTEM SHOULD BRING THE NEXT CHANCE OF PCPN...STARTING OUT AS A MIX OF RAIN AND SNOW SHOWERS MONDAY WITH SOME LINGERING LIGHT SNOW SHOWERS POSSIBLE INTO MONDAY NIGHT OR TUESDAY. CURRENT INDICATORS SUGGEST WEAK SFC FORCING AND MODERATE ISENTROPIC LIFT AHEAD OF AN ASSOCIATED COLD FRONT...SO...PCPN AMOUNTS SHOULD BE RELATIVELY LIGHT. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * MVFR CEILINGS TODAY...POSSIBLY PERSISTING INTO TONIGHT. RODRIGUEZ //DISCUSSION...UPDATED 18Z... WHILE VFR CEILINGS CONTINUE TO MOVE ACROSS THE TERMINALS...DIURNALLY DRIVEN MVFR CEILINGS HAVE DEVELOPED TODAY. HAVE HIGHER CONFIDENCE WITH THESE LOWER CEILINGS TO REMAIN OVERHEAD THIS AFTERNOON OR AT LEAST CONTINUE TO PERIODICALLY MOVE ACROSS THE TERMINALS BUT CONFIDENCE LOWERS INTO THIS EVENING WITH SOME POTENTIAL FOR THEM TO REMAIN. AT THIS TIME...LIKELY SCENARIO WILL BE FOR THEM TO SCATTER EARLY THIS EVENING. HOWEVER...ONCE AGAIN WEATHER PATTERN TONIGHT COULD ALLOW FOR REDEVELOPMENT OVERNIGHT. ALSO...HAVE LEFT OUT ANY FOG MENTION TONIGHT BUT THERE WILL BE POTENTIAL FOR AT LEAST SOME ISOLATED MVFR VIS/FOG TO DEVELOP. HIGH PRESSURE OVERHEAD THROUGH THE PERIOD WILL ALLOW FOR MAINLY LIGHT AND VARIABLE WINDS BUT WHEN THE WINDS DO HOLD ONTO A DIRECTION...WILL LIKELY BE SOME LIGHT WESTERLY COMPONENT. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH WITH WIND SPEED/DIRECTION. * MEDIUM HIGH WITH CEILINGS THIS AFTERNOON...LOW MEDIUM THIS EVENING/TONIGHT. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS. FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY NORTHEAST WINDS. SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST. SUNDAY...VFR. SOUTHWEST WINDS. MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR. TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE. KJB && .MARINE... 106 PM CST RELATIVELY QUIET WEATHER EXPECTED ACROSS LAKE MICHIGAN OVER THE NEXT SEVERAL DAYS...WITH THE ONLY PERIOD OF NOTE BEING FRIDAY AND FRIDAY NIGHT AS WINDS TURN NORTH-NORTHEAST AND INCREASE INTO THE 20-25 KT RANGE PARTICULARLY ON THE SOUTHERN HALF OR SO OF THE LAKE. THIS WILL BE IN RESPONSE TO AN AREA OF LOW PRESSURE WHICH WILL DEVELOP ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY...WHICH IS FORECAST TO DEEPEN AND MOVE NORTHEAST ACROSS THE GULF STATES/LOWER TENNESSEE VALLEY FRIDAY BEFORE REDEVELOPING ALONG THE MID-ATLANTIC COAST ON SATURRDAY AND MOVING NORTHEAST OFF THE NEW ENGLAND COAST ON SUNDAY. WINDS ON LAKE MICHIGAN LOOK TO INCREASE FRIDAY AFTERNOON...THEN WEAKEN LATE FRIDAY NIGHT/EARLY SATURDAY AS A RIDGE OF HIGH PRESSURE MOVES OVER THE WESTERN/NORTHERN LAKES. OTHERWISE...LONGER RANGE MODEL GUIDANCE INDICATES ANOTHER WEAKER LOW PRESSURE SYSTEM MAY DEVELOP OVER THE SOUTH-CENTRAL PLAINS SUNDAY NIGHT...MOVING TO THE GREAT LAKES REGION BY LATE MONDAY. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
107 PM CST WED JAN 20 2016 .UPDATE... 1051 AM CST FOR MORNING UPDATE... SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22 WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE WINDY/COLD OF THE PAST FEW DAYS. RATZER && .SHORT TERM... 313 AM CST THROUGH THURSDAY... PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY 12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW TEMPS. IZZI && .LONG TERM... 313 AM CST THURSDAY NIGHT THROUGH TUESDAY... ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING. OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST. POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO -12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS FOR SOME LIGHT SNOW SHOWERS OR FLURRIES. AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE SYSTEM. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * MVFR CEILINGS TODAY...POSSIBLY PERSISTING INTO TONIGHT. RODRIGUEZ //DISCUSSION...UPDATED 18Z... WHILE VFR CEILINGS CONTINUE TO MOVE ACROSS THE TERMINALS...DIURNALLY DRIVEN MVFR CEILINGS HAVE DEVELOPED TODAY. HAVE HIGHER CONFIDENCE WITH THESE LOWER CEILINGS TO REMAIN OVERHEAD THIS AFTERNOON OR AT LEAST CONTINUE TO PERIODICALLY MOVE ACROSS THE TERMINALS BUT CONFIDENCE LOWERS INTO THIS EVENING WITH SOME POTENTIAL FOR THEM TO REMAIN. AT THIS TIME...LIKELY SCENARIO WILL BE FOR THEM TO SCATTER EARLY THIS EVENING. HOWEVER...ONCE AGAIN WEATHER PATTERN TONIGHT COULD ALLOW FOR REDEVELOPMENT OVERNIGHT. ALSO...HAVE LEFT OUT ANY FOG MENTION TONIGHT BUT THERE WILL BE POTENTIAL FOR AT LEAST SOME ISOLATED MVFR VIS/FOG TO DEVELOP. HIGH PRESSURE OVERHEAD THROUGH THE PERIOD WILL ALLOW FOR MAINLY LIGHT AND VARIABLE WINDS BUT WHEN THE WINDS DO HOLD ONTO A DIRECTION...WILL LIKELY BE SOME LIGHT WESTERLY COMPONENT. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH WITH WIND SPEED/DIRECTION. * MEDIUM HIGH WITH CEILINGS THIS AFTERNOON...LOW MEDIUM THIS EVENING/TONIGHT. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS. FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY NORTHEAST WINDS. SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST. SUNDAY...VFR. SOUTHWEST WINDS. MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR. TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE. KJB && .MARINE... 106 PM CST RELATIVELY QUIET WEATHER EXPECTED ACROSS LAKE MICHIGAN OVER THE NEXT SEVERAL DAYS...WITH THE ONLY PERIOD OF NOTE BEING FRIDAY AND FRIDAY NIGHT AS WINDS TURN NORTH-NORTHEAST AND INCREASE INTO THE 20-25 KT RANGE PARTICULARLY ON THE SOUTHERN HALF OR SO OF THE LAKE. THIS WILL BE IN RESPONSE TO AN AREA OF LOW PRESSURE WHICH WILL DEVELOP ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY...WHICH IS FORECAST TO DEEPEN AND MOVE NORTHEAST ACROSS THE GULF STATES/LOWER TENNESSEE VALLEY FRIDAY BEFORE REDEVELOPING ALONG THE MID-ATLANTIC COAST ON SATURRDAY AND MOVING NORTHEAST OFF THE NEW ENGLAND COAST ON SUNDAY. WINDS ON LAKE MICHIGAN LOOK TO INCREASE FRIDAY AFTERNOON...THEN WEAKEN LATE FRIDAY NIGHT/EARLY SATURDAY AS A RIDGE OF HIGH PRESSURE MOVES OVER THE WESTERN/NORTHERN LAKES. OTHERWISE...LONGER RANGE MODEL GUIDANCE INDICATES ANOTHER WEAKER LOW PRESSURE SYSTEM MAY DEVELOP OVER THE SOUTH-CENTRAL PLAINS SUNDAY NIGHT...MOVING TO THE GREAT LAKES REGION BY LATE MONDAY. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1154 AM CST WED JAN 20 2016 .UPDATE... 1051 AM CST FOR MORNING UPDATE... SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22 WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE WINDY/COLD OF THE PAST FEW DAYS. RATZER && .SHORT TERM... 313 AM CST THROUGH THURSDAY... PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY 12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW TEMPS. IZZI && .LONG TERM... 313 AM CST THURSDAY NIGHT THROUGH TUESDAY... ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING. OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST. POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO -12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS FOR SOME LIGHT SNOW SHOWERS OR FLURRIES. AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE SYSTEM. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * MVFR CEILINGS TODAY...POSSIBLY PERSISTING INTO TONIGHT. RODRIGUEZ //DISCUSSION...UPDATED 18Z... WHILE VFR CEILINGS CONTINUE TO MOVE ACROSS THE TERMINALS...DIURNALLY DRIVEN MVFR CEILINGS HAVE DEVELOPED TODAY. HAVE HIGHER CONFIDENCE WITH THESE LOWER CEILINGS TO REMAIN OVERHEAD THIS AFTERNOON OR AT LEAST CONTINUE TO PERIODICALLY MOVE ACROSS THE TERMINALS BUT CONFIDENCE LOWERS INTO THIS EVENING WITH SOME POTENTIAL FOR THEM TO REMAIN. AT THIS TIME...LIKELY SCENARIO WILL BE FOR THEM TO SCATTER EARLY THIS EVENING. HOWEVER...ONCE AGAIN WEATHER PATTERN TONIGHT COULD ALLOW FOR REDEVELOPMENT OVERNIGHT. ALSO...HAVE LEFT OUT ANY FOG MENTION TONIGHT BUT THERE WILL BE POTENTIAL FOR AT LEAST SOME ISOLATED MVFR VIS/FOG TO DEVELOP. HIGH PRESSURE OVERHEAD THROUGH THE PERIOD WILL ALLOW FOR MAINLY LIGHT AND VARIABLE WINDS BUT WHEN THE WINDS DO HOLD ONTO A DIRECTION...WILL LIKELY BE SOME LIGHT WESTERLY COMPONENT. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH WITH WIND SPEED/DIRECTION. * MEDIUM HIGH WITH CEILINGS THIS AFTERNOON...LOW MEDIUM THIS EVENING/TONIGHT. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS. FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY NORTHEAST WINDS. SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST. SUNDAY...VFR. SOUTHWEST WINDS. MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR. TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE. KJB && .MARINE... 100 AM CST SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT ADVISORY FOR THE ILLINOIS AND INDIANA NEAR SHORES. HOWEVER...THERE ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR SHORES DUE TO THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO BE MONITORED OVER THE NEXT COUPLE DAYS. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1051 AM CST WED JAN 20 2016 .UPDATE... 1051 AM CST FOR MORNING UPDATE... SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22 WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE WINDY/COLD OF THE PAST FEW DAYS. RATZER && .SHORT TERM... 313 AM CST THROUGH THURSDAY... PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY 12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW TEMPS. IZZI && .LONG TERM... 313 AM CST THURSDAY NIGHT THROUGH TUESDAY... ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING. OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST. POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO -12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS FOR SOME LIGHT SNOW SHOWERS OR FLURRIES. AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE SYSTEM. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LINGERING LIGHT SNOW/FLURRIES OVER THE NEXT 1-2 HOURS. * MVFR CIGS REDEVELOPING. KJB/RODRIGUEZ //DISCUSSION...UPDATED 12Z... THE ACCUMULATING SNOW HAS COME TO AN END. HOWEVER...A FEW LINGERING FLURRIES COULD LINGER FOR THE NEXT FEW HOURS...BUT NO IMPACTS ARE EXPECTED. OTHERWISE...IT APPEARS THAT A PERIOD OF VFR CIGS OF 4-6 KFT AGL WILL BE THE RULE FOR THE NEXT FEW HOURS...BEFORE SOME LOWER MVFR CIGS REDEVELOP OVER THE AREA BY LATE MORNING. THESE LOWER CIGS COULD HANG ACROSS MUCH OF THE AREA THROUGH THE DAY. THERE IS A SMALL CHANCE OF SOME FOG DEVELOPMENT LATE TONIGHT...PARTICULARLY AT KRFD AND KDPA. HOWEVER...THERE IS UNCERTAINTY DUE TO THE POSSIBILITY OF CLOUD COVER. THEREFORE...I HAVE LEFT THE MENTION OUT OF THE TAFS AT THIS TIME. KJB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH WITH SNOW TRENDS. * MEDIUM WITH CEILING TRENDS. KJB/RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS. FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY NORTHEAST WINDS. SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST. SUNDAY...VFR. SOUTHWEST WINDS. MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR. TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE. KJB && .MARINE... 100 AM CST SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT ADVISORY FOR THE ILLINOIS AND INDIANA NEAR SHORES. HOWEVER...THERE ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR SHORES DUE TO THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO BE MONITORED OVER THE NEXT COUPLE DAYS. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...CORRECTED
NWS GOODLAND KS
231 PM MST WED JAN 20 2016 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 132 PM MST WED JAN 20 2016 WV IMAGERY AND RAP H5/H7 ANALYSIS SHOWS TWO SHORTWAVE TROUGHS IMPACTING THE CENTRAL ROCKIES AND PLAINS. THE STRONGER CLOSED CENTER JUST EAST OF OUR CWA OVER NORTH CENTRAL KANSAS AND HAS DEEPENED THROUGH MIDDAY. THE SECOND IS ENTERING EASTERN COLORADO. BETWEEN THESE FEATURES THERE IS A SHORTWAVE RIDGE AND REGION OF DRY/SUBSIDENT AIR APPARENT ON WV IMAGERY. AT THE SURFACE...A SURFACE TROUGH IS IN PLACE OVER EASTERN COLORADO AND WHERE SKIES HAVE CLEARED TEMPS HAVE WARMED IN TO THE 40S/50S. OVER OUR CWA (EAST OF TROUGH AXIS) EXTENSIVE CLOUD COVER HAS SIGNIFICANTLY LIMITED HEATING AND SEVERAL UPDATES TO HIGH TEMPS WERE WARRANTED EARLIER TODAY. THIS AFTERNOON-THURSDAY...FOCUS CONTINUES TO BE ON POTENTIAL FOR SNOW ACROSS OUR CWA. RADAR IS SHOWING SIGNS OF INCREASE IN REFLECTIVITY IN OUR EASTERN CWA AND HILL CITY HAS STARTED TO REPORT LIGHT SNOW. THIS CORRELATES WITH OF STRONG VORTICITY NEAR CLOSED LOW CENTER AND BETTER MID LEVEL MOISTURE IS BEGINNING TO FILL IT. TREND WILL BE FOR THIS CENTER TO ROTATE NORTH AND EAST TONIGHT BEFORE SLIDING WELL EAST OF OUR CWA. AN ELEVATED BAROCLINIC ZONE/REGION OF WEAK FRONTOGENESIS WILL DEVELOP AS THESE SHORTWAVE INTERACT AND PLACE THE NORTHERN HALF OF OUR CWA IN A FAVORABLE LOCATION FOR POSSIBLE LIGHT SNOW DEVELOPMENT BY THURSDAY MORNING. THE LIMITING FACTOR WILL BE MOISTURE ADVECTION AS BOTH SHORTWAVE WILL TEND TO CUT OFF GULF MOISTURE AND MODELS HAVE GENERALLY LIMITED QPF OVER OUR CWA ACCORDINGLY. IN THE MEAN TIME...THE DRY/SUBSIDENT REGION BETWEEN FEATURES MAY LIMIT ANY SNOW DEVELOPMENT IN OUR SOUTH. I FAVORED THE EASTERN/NORTHEAST PART OF OUR CWA TONIGHT AND THURSDAY MORNING FOR HIGHEST POPS. SNOW TOTALS SHOULD GENERALLY RANGE 0.5-1" THOUGH IF THE EASTERN SHORTWAVE WERE TO REMAIN CLOSER TO OUR CWA WE MAY HAVE A ROW OF COUNTIES RECEIVE AROUND 2" WHEN ALL IS SAID AND DONE. ALL SNOWFALL SHOULD QUICKLY DISSIPATE/TRANSITION EASTWARD AS THE RESULTING COMBINED TROUGH SHIFTS EAST AND RIDGING BUILDS INTO OUR CWA THURSDAY AFTERNOON. MODELS CONTINUE TO SHOW STRONGER BL WINDS DEVELOPING ON BACK SIDE OF UPPER LOW AS THE TWO SHORTWAVES MERGE AND POST FRONTAL PRESSURE GRADIENT INCREASES. LOCATION OF STRONGEST WINDS ACTUALLY CORRELATES WITH MOST LIKELY LOCATION OF DRY SLOT DEVELOPMENT AND ABOVE FREEZING TEMPERATURES DURING THE DAY THURSDAY. MIXING MAY BE LIMITED IN LOCATIONS WITH CLOUD COVER/SNOW AND BL WINDS ARE LESS TO THE NORTHEAST WHERE SNOWFALL IS MOST LIKELY. SINCE STRONGEST WINDS ARE UNLIKELY TO BE LOCATED WITH BETTER SNOW CHANCES AND ACCUMULATIONS ARE LIGHT I DID NOT SEE THE NEED TO KEEP BLOWING SNOW IN THE FORECAST. AT MOST WE MAY SEE A BRIEF PERIOD OF DRIFTING SNOW AS SNOW WINDS DOWN BEFORE TEMPS INCREASE TO FREEZING (OR WARMER). ANY DRIFTING WOULD BE MINOR CONSIDERING AMOUNTS WE ARE DEALING WITH AS WELL AS PEAK GUSTS IN THE REGION OF BETTER LIGHT SNOW ACCUMULATIONS 20-25 MPH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 132 PM MST WED JAN 20 2016 THERE ARE A COUPLE OF FORECAST CONCERNS IN THE LONG TERM PERIOD. FIRST IS THE TEMPERATURE GRADIENT ACROSS THE FORECAST AREA THROUGH THE END OF THE WEEK AND INTO THE WEEKEND AS COOLER AIR MOVES EAST AND WARMER DOWNSLOPING CONDITIONS OCCUR OVER THE WEST. SECOND IS THE POSSIBILITY AND TYPE OF PRECIPITATION LATE SUNDAY THROUGH EARLY MONDAY MORNING AS THE WARM AND DRY PATTERN TRANSITIONS BRIEFLY BACK TO A COOLER AND MORE ACTIVE PATTERN AS A SERIES OF DISTURBANCES MOVES ACROSS THE REGION LATE IN THE WEEKEND THROUGH EARLY NEXT WEEK. THE UPPER RIDGE MOVES EAST OVER THE HIGH PLAINS ON THURSDAY NIGHT THROUGH FRIDAY NIGHT AND CONTINUES OVER THE EASTERN PLAINS STATES ON SATURDAY. THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE MOVES INTO THE PLAINS STATES BY FRIDAY...WITH A LEE TROUGH DEEPENING ALONG THE FRONT RANGE IN RESPONSE TO THE FLATTENING UPPER FLOW AS AS SEVERAL SHORT WAVE TROUGHS MOVE THROUGH THE UPPER FLOW SATURDAY NIGHT AHEAD OF THE NEXT MAIN UPPER TROUGH AXIS. THIS WILL KEEP THE COOLER AIR OVER THE FAR EASTERN SECTIONS OF THE FORECAST AREA AS THE WESTERN SECTIONS WARM UP. THE THURSDAY NIGHT THROUGH SATURDAY NIGHT TIME PERIOD WILL STAY DRY AS A RESULT. HOWEVER...THE TEMPERATURE GRADIENT ACROSS MY FORECAST AREA IS USUALLY MORE DRAMATIC THAN DEPICTED BY ANY MODEL SOLUTIONS AND HAVE THEREFORE TRIED TO GO TOWARDS THE WARM END OF GUIDANCE OVER THE WEST AND TOWARDS THE COOL END OF GUIDANCE OVER THE EAST TO MAKE THE GRADIENT MORE DRAMATIC. ANY RELUCTANCE OF LOW CLOUD COVER TO DISSIPATE OVER THE EASTERN SECTIONS...AS HAS BEEN THE CASE OVER RECENT DAYS...WILL ALSO ACT TO INCREASE THE TEMPERATURE GRADIENT. A SURFACE LOW CONSOLIDATES OVER THE NORTHERN PANHANDLE REGION ON SUNDAY...LIFTING INTO MISSOURI BY MONDAY MORNING ALONG THE FRONTAL BOUNDARY EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN PLAINS AS THE MAIN UPPER TROUGH AXIS MOVES EAST OF THE ROCKIES BY SUNDAY AFTERNOON. A DEEPER AND BROADER UPPER TROUGH IS EVENTUALLY CARVED OUT OVER MUCH OF THE UNITED STATES EAST OF THE ROCKIES BY MONDAY NIGHT AS ANOTHER RIDGE MOVES INTO PLACE OVER THE WEST COAST. THIS WILL OPEN THE DOOR TO COLDER AIR DIVING SOUTH INTO THE PLAINS STATES ON MONDAY. WITH THE TRACK OF THE SURFACE LOW REMAINING WELL SOUTH OF THE FORECAST AREA AND LITTLE MOISTURE TO WORK WITH...EXPECT ONLY A SLIGHT CHANCE OF LIGHT RAIN OR SNOW LATE SUNDAY TRANSITIONING TO ALL SNOW SUNDAY EVENING...WITH MINIMAL ACCUMULATIONS POSSIBLE MAINLY ACROSS SOUTHERN NEBRASKA AND EASTERN COLORADO. THE UPPER WEST COAST RIDGE FLATTENS AND MOVES EAST OVER THE MOUNTAINOUS WEST BETWEEN SUNDAY AND WEDNESDAY WITH ANOTHER LEE TROUGH DEEPENING ALONG THE FRONT RANGE. WESTERLY NEAR SURFACE FLOW WILL PRODUCE DRYING CONDITIONS AND WARMING TEMPERATURES AGAIN OVER THE FORECAST AREA ON TUESDAY AND WEDNESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1026 AM MST WED JAN 20 2016 BASED ON RECENT TRENDS WITH OBS AND SUPPORTED BY SHORT RANGE GUIDANCE IFR CIGS/VIS SHOULD IMPROVE TO VFR DURING THE EARLY PART OF THE TAF PERIOD. A COLD FRONT WILL MOVE THROUGH THE REGION LATE THIS EVENING WITH WINDS SHIFTING TO THE NORTHWEST AND INCREASING THROUGH THE NIGHT. STRATUS WILL ONCE AGAIN DEVELOP BEHIND THIS FRONT LATE TONIGHT AND THURSDAY MORNING...AND THERE COULD BE A FEW SNOW SHOWERS AROUND THE REGION. THERE IS STILL ENOUGH UNCERTAINTY IN SNOW COVERAGE I WAS MOST COMFORTABLE LIMITING MENTION TO VCSH THURSDAY MORNING AT KMCK WHERE BETTER CHANCES ARE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...LOCKHART AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
219 PM MST WED JAN 20 2016 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 132 PM MST WED JAN 20 2016 WV IMAGERY AND RAP H5/H7 ANALYSIS SHOWS TWO SHORTWAVE TROUGHS IMPACTING THE CENTRAL ROCKIES AND PLAINS. THE STRONGER CLOSED CENTER JUST EAST OF OUR CWA OVER NORTH CENTRAL KANSAS AND HAS DEEPENED THROUGH MIDDAY. THE SECOND IS ENTERING EASTERN COLORADO. BETWEEN THESE FEATURES THERE IS A SHORTWAVE RIDGE AND REGION OF DRY/SUBSIDENT AIR APPARENT ON WV IMAGERY. AT THE SURFACE...A SURFACE TROUGH IS IN PLACE OVER EASTERN COLORADO AND WHERE SKIES HAVE CLEARED TEMPS HAVE WARMED IN TO THE 40S/50S. OVER OUR CWA (EAST OF TROUGH AXIS) EXTENSIVE CLOUD COVER HAS SIGNIFICANTLY LIMITED HEATING AND SEVERAL UPDATES TO HIGH TEMPS WERE WARRANTED EARLIER TODAY. THIS AFTERNOON-THURSDAY...FOCUS CONTINUES TO BE ON POTENTIAL FOR SNOW ACROSS OUR CWA. RADAR IS SHOWING SIGNS OF INCREASE IN REFLECTIVITY IN OUR EASTERN CWA AND HILL CITY HAS STARTED TO REPORT LIGHT SNOW. THIS CORRELATES WITH OF STRONG VORTICITY NEAR CLOSED LOW CENTER AND BETTER MID LEVEL MOISTURE IS BEGINNING TO FILL IT. TREND WILL BE FOR THIS CENTER TO ROTATE NORTH AND EAST TONIGHT BEFORE SLIDING WELL EAST OF OUR CWA. AN ELEVATED BAROCLINIC ZONE/REGION OF WEAK FRONTOGENESIS WILL DEVELOP AS THESE SHORTWAVE INTERACT AND PLACE THE NORTHERN HALF OF OUR CWA IN A FAVORABLE LOCATION FOR POSSIBLE LIGHT SNOW DEVELOPMENT BY THURSDAY MORNING. THE LIMITING FACTOR WILL BE MOISTURE ADVECTION AS BOTH SHORTWAVE WILL TEND TO CUT OFF GULF MOISTURE AND MODELS HAVE GENERALLY LIMITED QPF OVER OUR CWA ACCORDINGLY. IN THE MEAN TIME...THE DRY/SUBSIDENT REGION BETWEEN FEATURES MAY LIMIT ANY SNOW DEVELOPMENT IN OUR SOUTH. I FAVORED THE EASTERN/NORTHEAST PART OF OUR CWA TONIGHT AND THURSDAY MORNING FOR HIGHEST POPS. SNOW TOTALS SHOULD GENERALLY RANGE 0.5-1" THOUGH IF THE EASTERN SHORTWAVE WERE TO REMAIN CLOSER TO OUR CWA WE MAY HAVE A ROW OF COUNTIES RECEIVE AROUND 2" WHEN ALL IS SAID AND DONE. ALL SNOWFALL SHOULD QUICKLY DISSIPATE/TRANSITION EASTWARD AND THE RESULTING COMBINED TROUGH SHIFTS EAST AND RIDING BUILDS INTO OUR CWA THURSDAY. MODELS CONTINUE TO SHOW STRONGER BL WINDS DEVELOPING ON BACK SIDE OF UPPER LOW AS THE TWO SHORTWAVES MERGE AND POST FRONTAL PRESSURE GRADIENT INCREASES. LOCATION OF STRONGEST WINDS ACTUALLY CORRELATES WITH MOST LIKELY LOCATION OF DRY SLOT DEVELOPMENT AND ABOVE FREEZING TEMPERATURES DURING THE DAY THURSDAY. MIXING MAY BE LIMITED IN LOCATIONS WITH CLOUD COVER/SNOW AND BL WINDS ARE LESS TO THE NORTHEAST WHERE SNOWFALL IS MOST LIKELY. SINCE STRONGEST WINDS ARE UNLIKELY TO BE LOCATED WITH BETTER SNOW CHANCES AND ACCUMULATIONS ARE LIGHT I DID NOT SEE THE NEED TO KEEP BLOWING SNOW IN THE FORECAST. AT MOST WE MAY SEE A BRIEF PERIOD OF DRIFTING SNOW AS SNOW WINDS DOWN BEFORE TEMPS INCREASE TO FREEZING (OR WARMER). ANY DRIFTING WOULD BE MINOR AS WELL WITH PEAK GUSTS IN THE REGION OF BETTER LIGHT SNOW ACCUMULATIONS 20-25 MPH. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 132 PM MST WED JAN 20 2016 THERE ARE A COUPLE OF FORECAST CONCERNS IN THE LONG TERM PERIOD. FIRST IS THE TEMPERATURE GRADIENT ACROSS THE FORECAST AREA THROUGH THE END OF THE WEEK AND INTO THE WEEKEND AS COOLER AIR MOVES EAST AND WARMER DOWNSLOPING CONDITIONS OCCUR OVER THE WEST. SECOND IS THE POSSIBILITY AND TYPE OF PRECIPITATION LATE SUNDAY THROUGH EARLY MONDAY MORNING AS THE WARM AND DRY PATTERN TRANSITIONS BRIEFLY BACK TO A COOLER AND MORE ACTIVE PATTERN AS A SERIES OF DISTURBANCES MOVES ACROSS THE REGION LATE IN THE WEEKEND THROUGH EARLY NEXT WEEK. THE UPPER RIDGE MOVES EAST OVER THE HIGH PLAINS ON THURSDAY NIGHT THROUGH FRIDAY NIGHT AND CONTINUES OVER THE EASTERN PLAINS STATES ON SATURDAY. THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE MOVES INTO THE PLAINS STATES BY FRIDAY...WITH A LEE TROUGH DEEPENING ALONG THE FRONT RANGE IN RESPONSE TO THE FLATTENING UPPER FLOW AS AS SEVERAL SHORT WAVE TROUGHS MOVE THROUGH THE UPPER FLOW SATURDAY NIGHT AHEAD OF THE NEXT MAIN UPPER TROUGH AXIS. THIS WILL KEEP THE COOLER AIR OVER THE FAR EASTERN SECTIONS OF THE FORECAST AREA AS THE WESTERN SECTIONS WARM UP. THE THURSDAY NIGHT THROUGH SATURDAY NIGHT TIME PERIOD WILL STAY DRY AS A RESULT. HOWEVER...THE TEMPERATURE GRADIENT ACROSS MY FORECAST AREA IS USUALLY MORE DRAMATIC THAN DEPICTED BY ANY MODEL SOLUTIONS AND HAVE THEREFORE TRIED TO GO TOWARDS THE WARM END OF GUIDANCE OVER THE WEST AND TOWARDS THE COOL END OF GUIDANCE OVER THE EAST TO MAKE THE GRADIENT MORE DRAMATIC. ANY RELUCTANCE OF LOW CLOUD COVER TO DISSIPATE OVER THE EASTERN SECTIONS...AS HAS BEEN THE CASE OVER RECENT DAYS...WILL ALSO ACT TO INCREASE THE TEMPERATURE GRADIENT. A SURFACE LOW CONSOLIDATES OVER THE NORTHERN PANHANDLE REGION ON SUNDAY...LIFTING INTO MISSOURI BY MONDAY MORNING ALONG THE FRONTAL BOUNDARY EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN PLAINS AS THE MAIN UPPER TROUGH AXIS MOVES EAST OF THE ROCKIES BY SUNDAY AFTERNOON. A DEEPER AND BROADER UPPER TROUGH IS EVENTUALLY CARVED OUT OVER MUCH OF THE UNITED STATES EAST OF THE ROCKIES BY MONDAY NIGHT AS ANOTHER RIDGE MOVES INTO PLACE OVER THE WEST COAST. THIS WILL OPEN THE DOOR TO COLDER AIR DIVING SOUTH INTO THE PLAINS STATES ON MONDAY. WITH THE TRACK OF THE SURFACE LOW REMAINING WELL SOUTH OF THE FORECAST AREA AND LITTLE MOISTURE TO WORK WITH...EXPECT ONLY A SLIGHT CHANCE OF LIGHT RAIN OR SNOW LATE SUNDAY TRANSITIONING TO ALL SNOW SUNDAY EVENING...WITH MINIMAL ACCUMULATIONS POSSIBLE MAINLY ACROSS SOUTHERN NEBRASKA AND EASTERN COLORADO. THE UPPER WEST COAST RIDGE FLATTENS AND MOVES EAST OVER THE MOUNTAINOUS WEST BETWEEN SUNDAY AND WEDNESDAY WITH ANOTHER LEE TROUGH DEEPENING ALONG THE FRONT RANGE. WESTERLY NEAR SURFACE FLOW WILL PRODUCE DRYING CONDITIONS AND WARMING TEMPERATURES AGAIN OVER THE FORECAST AREA ON TUESDAY AND WEDNESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1026 AM MST WED JAN 20 2016 BASED ON RECENT TRENDS WITH OBS AND SUPPORTED BY SHORT RANGE GUIDANCE IFR CIGS/VIS SHOULD IMPROVE TO VFR DURING THE EARLY PART OF THE TAF PERIOD. A COLD FRONT WILL MOVE THROUGH THE REGION LATE THIS EVENING WITH WINDS SHIFTING TO THE NORTHWEST AND INCREASING THROUGH THE NIGHT. STRATUS WILL ONCE AGAIN DEVELOP BEHIND THIS FRONT LATE TONIGHT AND THURSDAY MORNING...AND THERE COULD BE A FEW SNOW SHOWERS AROUND THE REGION. THERE IS STILL ENOUGH UNCERTAINTY IN SNOW COVERAGE I WAS MOST COMFORTABLE LIMITING MENTION TO VCSH THURSDAY MORNING AT KMCK WHERE BETTER CHANCES ARE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...LOCKHART AVIATION...DR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
316 PM EST WED JAN 20 2016 .SYNOPSIS... A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS. P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES THIS AFTN BEFORE THICKER CLDNS ARRIVES. ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH. HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S. WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE LEANED TOWARD THE COOLER MET NUMBERS. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES. FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN. FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN. AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND THERMODYNAMIC PROFILES CHANGE. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S BY MON. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID TO LATE AFTN TODAY. HOWEVER...CLOUDS WILL INCREASE AND LOWER QUICKLY FROM WEST TO EAST AS AN UPPER LEVEL SYSTEM SWINGS THROUGH THE REGION THIS EVENING. THIS SYSTEM WILL BRING A QUICK ROUND OF LIGHT SNOW TO ALL TAF SITES FROM ROUGHLY 20/2300Z TO 21/0800Z. CONDITIONS DROP TO MVFR WITH CIGS AROUND 2500FT AGL AND VISIBILITIES AROUND 3-4SM IN -SN. LIGHT AND VARIABLE WINDS THIS AFTN WILL SHIFT TO THE NW AFTER MIDNIGHT TONIGHT INTO THURSDAY MORNING BEHIND THE PASSING SYSTEM. WINDS EXPECTED TO GUST UP TO 15-20KT ALONG CHES BAY AND THE ATLANTIC COAST AS STRONGER WINDS MIX DOWN OVER THE WATERS. HIGH PRESSURE PASSES OVER THE AREA ON THURSDAY. A STRONG WINTER STORM WILL THEN AFFECT THE REGION LATE THU NIGHT INTO THE WEEKEND. RAPIDLY DETERIORATING CONDITIONS DUE TO LOW CIG/VIS RESTRICTIONS SHOULD BE ANTICIPATED BEGINNING FRIDAY AFTN. && .MARINE... AN ACTIVE WEATHER PATTERN WILL PREVAIL IN THE MARINE AREA FOR THE NEXT SEVERAL DAYS. A WELL ADVERTISED STORM SYSTEM WILL PRODUCE ROUGH CONDITIONS BEGINNING FRIDAY NIGHT. IN THE MEANTIME...A WEAK LOW PRESSURE SYSTEM WILL MOVE THROUGH OVERNIGHT. BEHIND IT NW WINDS WILL TEMPORARILY INCREASE. A SCA IS IN EFFECT FOR THE CHESAPEAKE BAY AND CURRITUCK SOUND LATE TONIGHT THROUGH MID MORNING THURSDAY. HIGH PRESSURE BUILDS OVER THE WATERS THURSDAY AND THURSDAY NIGHT. A DEVELOPING STORM SYSTEM OVER THE SOUTHERN STATES WILL EVENTUALLY DEVELOP A LOW PRESSURE SYSTEM ON THE NORTH CAROLINA COAST. THIS LOW WILL INTENSIFY FRIDAY EVENING. NE WINDS INCREASE RAPIDLY AROUND 00Z FRIDAY EVENING. THE LOW MOVES TO OFF THE MD/VA COAST SATURDAY. STRONG SCA TO GALE FORCE WINDS CAN BE EXPECTED AFTER MIDNIGHT FRIDAY NIGHT INTO SATURDAY MORNING WITH GUSTS OVER 40 KNOTS EXPECTED IN THE BAY AND COASTAL WATERS. SOLID SCA WINDS CONTINUES INTO SUNDAY. SEAS IN THE COASTAL WATERS WILL REMAIN 5 FT OR HIGHER THROUGH MONDAY MORNING. THE PRESSURE PATTERN WEAKENS EARLY NEXT WEEK WITH QUIET MARINE WEATHER DURING MUCH OF NEXT WEEK. && .TIDES/COASTAL FLOODING... LOW WATER ADVISORY EXTENDED THROUGH LATE THURSDAY AFTN FOR ALL MARINE ZONES EXCEPT CURRITUCK SOUND...AND NC COASTAL WATERS DUE TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN LOWER LOW WATER. ADDED THE UPPER AND LOWER JAMES RIVER SINCE THE JAMESTOWN BUOY HAS BEEN MEASURING BLOWOUT TIDES BTWN 1-2 FT BELOW MLLW. TIDAL ANOMALIES ARE FORECAST TO INCREASE TO 1.5 TO 2.0 FT LATE FRI INTO SAT...AS LO PRES IMPACTS THE REGION. THE COMBINATION OF STRONG ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES REACHING MHHW WILL PUSH COASTAL AREAS OF THE MD/VA EASTERN SHORE AND SRN CHES BAY TOWARD MINOR FLOODING THRESHOLDS. STRONG NW WINDS BEHIND THE DEPARTING SYSTEM WILL POTENTIALLY FAVOR MINOR FLOODING OF THE CHESAPEAKE BAY SIDE OF THE LOWER EASTERN SHORE. GALE CONDITIONS POSSIBLE LATE FRI NIGHT INTO SAT WITH SEAS BUILDING TO 5 TO 12 FT COULD RESULT IN BEACH AND GENERAL SHORELINE EROSION...ESPECIALLY FROM CHES BAY NWD ALONG THE ATLANTIC COAST. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH SUNDAY MORNING FOR MDZ021>023. NC...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH SUNDAY MORNING FOR NCZ012. VA...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH SUNDAY MORNING FOR VAZ048-060>062-064>069-075>090-092-509>522. MARINE...LOW WATER ADVISORY UNTIL 3 PM EST THURSDAY FOR ANZ650-652-654- 656. LOW WATER ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ630>632-634- 637-638. SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EST THURSDAY FOR ANZ630>634. && $$ SYNOPSIS...AJZ NEAR TERM...ALB/ESS SHORT TERM...ESS LONG TERM...MAS AVIATION...BMD/TMG MARINE...LSA TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
118 PM EST WED JAN 20 2016 .SYNOPSIS... A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS. P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES THIS AFTN BEFORE THICKER CLDNS ARRIVES. ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH. HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S. WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE LEANED TOWARD THE COOLER MET NUMBERS. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES. FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN. FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN. AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND THERMODYNAMIC PROFILES CHANGE. && .LONG TERM /SATURDAY THROUGH TUESDAY/... LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S BY MON. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID TO LATE AFTN TODAY. HOWEVER...CLOUDS WILL INCREASE AND LOWER QUICKLY FROM WEST TO EAST AS AN UPPER LEVEL SYSTEM SWINGS THROUGH THE REGION THIS EVENING. THIS SYSTEM WILL BRING A QUICK ROUND OF LIGHT SNOW TO ALL TAF SITES FROM ROUGHLY 20/2300Z TO 21/0800Z. CONDITIONS DROP TO MVFR WITH CIGS AROUND 2500FT AGL AND VISIBILITIES AROUND 3-4SM IN -SN. LIGHT AND VARIABLE WINDS THIS AFTN WILL SHIFT TO THE NW AFTER MIDNIGHT TONIGHT INTO THURSDAY MORNING BEHIND THE PASSING SYSTEM. WINDS EXPECTED TO GUST UP TO 15-20KT ALONG CHES BAY AND THE ATLANTIC COAST AS STRONGER WINDS MIX DOWN OVER THE WATERS. HIGH PRESSURE PASSES OVER THE AREA ON THURSDAY. A STRONG WINTER STORM WILL THEN AFFECT THE REGION LATE THU NIGHT INTO THE WEEKEND. RAPIDLY DETERIORATING CONDITIONS DUE TO LOW CIG/VIS RESTRICTIONS SHOULD BE ANTICIPATED BEGINNING FRIDAY AFTN. && .MARINE... UPDATE... SCA FLAGS ISSUED FOR CHES BAY AND CURRITUCK SOUND AFTER MIDNIGHT TONIGHT INTO MID-THURSDAY MORNING AS NW WINDS INCREASE TO 15-20KT BEHIND A SHORTWAVE PASSING THROUGH THE REGION THIS EVENING. WINDS ALSO 15-20KT OVER ALL COASTAL WATERS BUT NOT STRONG ENOUGH TO SUPPORT 25KT GUST CRITERIA FOR SCA FLAGS. PREVIOUS DISCUSSION... HIGH PRESSURE WILL BUILD RIGHT OVER THE WATERS THIS AFTN...THEN WEAKEN AS AN UPPER LEVEL SYSTEM SLIDES ACROSS THE AREA AND OFF THE COAST THIS EVENING. WINDS WILL BECOME WSW THIS AFTN THRU EARLY TONIGHT...THEN BECOME NW AGAIN LATE TONIGHT INTO THU MORNING BEHIND THE SYSTEM. HIGH PRES BUILDS INTO AND OVER THE AREA DURING THU. ATTENTION THEN TURNS TO A POTENT STORM SYSTEM SET TO IMPACT THE REGION FRI INTO SUN. INCREASINGLY POOR BOATING CONDITIONS ANTICIPATED BY LATER FRI THRU THE WEEKEND. NNW WINDS VEER AROUND TO THE NNE EARLY FRI...THEN INCREASE FRI AFTN/EVENING...AS LOW PRESSURE LIFTS ALONG THE SE COAST AND HIGH PRESSURE BUILDS INTO CANADA. THE SFC LOW LIFTS OFF THE MID ATLANTIC COAST FRI NIGHT INTO SAT...LIFTING AWAY FROM THE COAST SAT THRU SUN. STRONG SCA WINDS EXPECTED LATER FRI INTO SUN...WITH GALE FORCE WINDS POSSIBLE OVR THE COASTAL WATERS AND CHES BAY LATE FRI NIGHT INTO SUN...AS FLOW TURNS FROM NE TO NNW. SEAS WILL ALSO BUILD QUICKLY REACHING AS HIGH AS 8-12 FT SAT. && .TIDES/COASTAL FLOODING... LOW WATER ADVISORY EXTENDED THROUGH LATE THURSDAY AFTN FOR ALL MARINE ZONES EXCEPT CURRITUCK SOUND...AND NC COASTAL WATERS DUE TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN LOWER LOW WATER. ADDED THE UPPER AND LOWER JAMES RIVER SINCE THE JAMESTOWN BUOY HAS BEEN MEASURING BLOWOUT TIDES BTWN 1-2 FT BELOW MLLW. TIDAL ANOMALIES ARE FORECAST TO INCREASE TO 1.5 TO 2.0 FT LATE FRI INTO SAT...AS LO PRES IMPACTS THE REGION. THE COMBINATION OF STRONG ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES REACHING MHHW WILL PUSH COASTAL AREAS OF THE MD/VA EASTERN SHORE AND SRN CHES BAY TOWARD MINOR FLOODING THRESHOLDS. STRONG NW WINDS BEHIND THE DEPARTING SYSTEM WILL POTENTIALLY FAVOR MINOR FLOODING OF THE CHESAPEAKE BAY SIDE OF THE LOWER EASTERN SHORE. GALE CONDITIONS POSSIBLE LATE FRI NIGHT INTO SAT WITH SEAS BUILDING TO 5 TO 12 FT COULD RESULT IN BEACH AND GENERAL SHORELINE EROSION...ESPECIALLY FROM CHES BAY NWD ALONG THE ATLANTIC COAST. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...LOW WATER ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ630>632-634- 637-638. SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EST THURSDAY FOR ANZ630>634. LOW WATER ADVISORY UNTIL 3 PM EST THURSDAY FOR ANZ650-652-654- 656. && $$ SYNOPSIS...AJZ NEAR TERM...ALB/ESS SHORT TERM...ESS LONG TERM...MAS AVIATION...BMD/TMG MARINE...BMD/TMG TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1232 PM EST WED JAN 20 2016 .SYNOPSIS... A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH THURSDAY/... FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS. P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES THIS AFTN BEFORE THICKER CLDNS ARRIVES. ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH. HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S. WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE LEANED TOWARD THE COOLER MET NUMBERS. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES. FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN. FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN. AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND THERMODYNAMIC PROFILES CHANGE. && .LONG TERM /SATURDAY THROUGH TUESDAY/... LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S BY MON. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID AFTN TODAY. BUT...CLOUDS WILL INCREASE AND LWR QUICKLY...AS AN UPR LEVEL SYSTEM MOVES TOWARDS THE REGION. THAT UPR LEVEL SYSTEM WILL THEN CROSS THE REGION LATE THIS AFTN INTO EARLY TNGT...BRINGING A CHC FOR SOME LIGHT SNOW. MAINLY VFR CIGS ARE STILL EXPECTED AS THE LIGHT SNOW MOVES THRU. HOWEVER...MVFR CIGS WILL BE POSSIBLE...ESPLY AT RIC/SBY/PHF. NW WINDS EARLY TODAY...WILL SHIFT TO THE W THEN SW LATE THIS MORNG INTO EARLY TNGT...THEN BACK AGAIN TO THE NW OVRNGT TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES WILL PASS OVER THE AREA ON THU. A STRONG WINTER STORM WILL THEN AFFECT THE REGION LATE THU NGT INTO THE WEEKEND. && .MARINE... SCA CONDITIONS WILL CONTINUE UNTIL 10 AM THIS MORNG OVR ALL WTRS EXCEPT THE RIVERS...DUE TO RATHER STRONG NW WINDS STILL OCCURRING AS HI PRES BLDS JUST TO THE W OF THE WTRS. THE HI WILL BLD RIGHT OVR THE WTRS EARLY THIS AFTN...THEN WEAKEN AS AN UPR LEVEL SYSTEM SLIDES ACRS THE AREA AND OFF THE CST LATE THIS AFTN INTO EARLY TNGT. WINDS WILL BECOME WSW THIS AFTN THRU EARLY TNGT...THEN BECOME NW AGAIN LATE TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES BLDS INTO AND OVR THE AREA DURING THU. ATTENTION THEN TURNS TO A POTENT STORM SYSTEM SET TO IMPACT THE REGION FRI INTO SUN. INCREASINGLY POOR BOATING CONDITIONS ANTICIPATED BY LATER FRI THRU THE WEEKEND. NNW WINDS VEER AROUND TO THE NNE EARLY FRI...THEN INCREASE FRI AFTN/EVENG...AS LO PRES LIFTS ALONG THE SE CST AND HI PRES BLDS INTO CANADA. THE SFC LOW LIFTS OFF THE MID-ATLC CST FRI NIGHT INTO SAT...LIFTING AWAY FM THE CST SAT THRU SUN. STRONG SCA WINDS EXPECTED LATER FRI INTO SUN...WITH GALE FORCE WINDS POSSIBLE OVR THE CSTL WTRS AND CHES BAY LATE FRI NGT INTO SUN...AS FLO TURNS FM NE TO NNW. SEAS WILL ALSO BLD QUICKLY REACHING AS HIGH AS 8-12+ FT SAT. && .TIDES/COASTAL FLOODING... LOW WATER ADVISORY EXTENDED THROUGH LATE THURSDAY AFTN FOR ALL MARINE ZONES EXCEPT CURRITUCK SOUND...AND NC COASTAL WATERS DUE TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN LOWER LOW WATER. ADDED THE UPPER AND LOWER JAMES RIVER SINCE THE JAMESTOWN BUOY HAS BEEN MEASURING BLOWOUT TIDES BTWN 1-2 FT BELOW MLLW. TIDAL ANOMALIES ARE FORECAST TO INCREASE TO 1.5 TO 2.0 FT LATE FRI INTO SAT...AS LO PRES IMPACTS THE REGION. THE COMBINATION OF STRONG ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES REACHING MHHW WILL PUSH COASTAL AREAS OF THE MD/VA EASTERN SHORE AND SRN CHES BAY TOWARD MINOR FLOODING THRESHOLDS. STRONG NW WINDS BEHIND THE DEPARTING SYSTEM WILL POTENTIALLY FAVOR MINOR FLOODING OF THE CHESAPEAKE BAY SIDE OF THE LOWER EASTERN SHORE. GALE CONDITIONS POSSIBLE LATE FRI NIGHT INTO SAT WITH SEAS BUILDING TO 5 TO 12 FT COULD RESULT IN BEACH AND GENERAL SHORELINE EROSION...ESPECIALLY FROM CHES BAY NWD ALONG THE ATLANTIC COAST. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...LOW WATER ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ630>632-634- 637-638. SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EST THURSDAY FOR ANZ630>634. LOW WATER ADVISORY UNTIL 3 PM EST THURSDAY FOR ANZ650-652-654- 656. && $$ SYNOPSIS...AJZ NEAR TERM...ALB/ESS SHORT TERM...ESS LONG TERM...MAS AVIATION...TMG MARINE...TMG TIDES/COASTAL FLOODING...BMD
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
150 PM EST WED JAN 20 2016 LATEST UPDATE... HYDRO .SYNOPSIS... ISSUED AT 315 AM EST WED JAN 20 2016 AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY. TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS WEEKEND OR EARLY NEXT WEEK. && .UPDATE... ISSUED AT 1233 PM EST WED JAN 20 2016 THE MESO-SCALE HEAVY SNOW BAND AS MOVES SOMEWHAT TO THE SOUTH AND IS NOW MOSTLY BETWEEN MUSKEGON AND GRAND HAVEN. DUAL POLE RADAR SHOWS STORM TOTALS BETWEEN 3 TO 4 INCHES HAS FALLEN IN THAT AREA. SINCE THE LATEST MODEL DATA SUGGESTS THE BAND WILL NOT START MOVING ON SHORE UNTIL AROUND 3 PM... I EXTENDED THE ADVIOSRY TILL 4 PM. UPDATE ISSUED AT 1102 AM EST WED JAN 20 2016 I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW. THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION. REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES WITH FLURRIES. UPDATE ISSUED AT 551 AM EST WED JAN 20 2016 CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY GIVEN CURRENT TRENDS: A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6 HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO WHITEHALL. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 315 AM EST WED JAN 20 2016 LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN INCH OF SNOW. THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN EFFECT UNTIL 18Z THIS AFTN. TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 315 AM EST WED JAN 20 2016 OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK. THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S. UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT THIS EARLY STAGE. THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW. RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE. FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR TRENDS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1243 PM EST WED JAN 20 2016 LIGHT SNOW WILL GRADUALLY DIMINISH AT MKG THIS AFTERNOON. SLIGHTLY WARMER AND MORE MOIST AIR WILL MOVE ACROSS LOWER MICHIGAN TONIGHT LEADING TO MVFR CIGS. && .MARINE... ISSUED AT 315 AM EST WED JAN 20 2016 WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF THE NEARSHORE WATERS. && .HYDROLOGY... ISSUED AT 150 PM EST WED JAN 20 2016 ICE JAMS HAVE FORMED IN SPOTS ALONG SEVERAL RIVERS. A GENERAL RISE IN RIVER LEVELS WITH OCCASIONAL DOWNWARD FLUCTUATIONS HAS BEEN OCCURRING IN SPOTS SUCH AS IONIA... EAGLE... SMYRNA... AND SCOTTVILLE. IONIA HAS SUPASSED BANKFULL THIS AFTERNOON AND THE OTHER THREE ARE CONTENDERS THE NEXT FEW DAYS. WITH BELOW-FREEZING WEATHER CONTINUING THROUGH THE REMAINDER OF THE WEEK... LITTLE CHANGE IN THE ICE JAMS IS EXPECTED... AND RIVER LEVELS SH0ULD REMAIN ELEVATED UPSTREAM OF THE JAMS. SIGNIFICANT FLOODING IS NOT AN IMMEDIATE CONCERN. NEVERTHELESS... ICE JAMS CAN CAUSE RELATIVELY RAPID CHANGES IN RIVER LEVELS UPSTREAM AND DOWNSTREAM OF THE JAM WITH LITTLE ADVANCE NOTICE. CONTINUE TO MONITOR FUTURE FORECASTS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ050- 056-064. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...HOVING AVIATION...04 HYDROLOGY...CAS MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1246 PM EST WED JAN 20 2016 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 315 AM EST WED JAN 20 2016 AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY. TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS WEEKEND OR EARLY NEXT WEEK. && .UPDATE... ISSUED AT 1233 PM EST WED JAN 20 2016 THE MESO-SCALE HEAVY SNOW BAND AS MOVES SOMEWHAT TO THE SOUTH AND IS NOW MOSTLY BETWEEN MUSKEGON AND GRAND HAVEN. DUAL POLE RADAR SHOWS STORM TOTALS BETWEEN 3 TO 4 INCHES HAS FALLEN IN THAT AREA. SINCE THE LATEST MODEL DATA SUGGESTS THE BAND WILL NOT START MOVING ON SHORE UNTIL AROUND 3 PM... I EXTENDED THE ADVIOSRY TILL 4 PM. UPDATE ISSUED AT 1102 AM EST WED JAN 20 2016 I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW. THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION. REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES WITH FLURRIES. UPDATE ISSUED AT 551 AM EST WED JAN 20 2016 CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY GIVEN CURRENT TRENDS: A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6 HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO WHITEHALL. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 315 AM EST WED JAN 20 2016 LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN INCH OF SNOW. THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN EFFECT UNTIL 18Z THIS AFTN. TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 315 AM EST WED JAN 20 2016 OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK. THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S. UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT THIS EARLY STAGE. THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW. RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE. FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR TRENDS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1243 PM EST WED JAN 20 2016 LIGHT SNOW WILL GRADUALLY DIMINISH AT MKG THIS AFTERNOON. SLIGHTLY WARMER AND MORE MOIST AIR WILL MOVE ACROSS LOWER MICHIGAN TONIGHT LEADING TO MVFR CIGS. && .MARINE... ISSUED AT 315 AM EST WED JAN 20 2016 WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF THE NEARSHORE WATERS. && .HYDROLOGY... ISSUED AT 324 PM EST TUE JAN 19 2016 WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING... HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ050- 056-064. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...HOVING AVIATION...04 HYDROLOGY...WDM MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1237 PM EST WED JAN 20 2016 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 315 AM EST WED JAN 20 2016 AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY. TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS WEEKEND OR EARLY NEXT WEEK. && .UPDATE... ISSUED AT 1233 PM EST WED JAN 20 2016 THE MESO-SCALE HEAVY SNOW BAND AS MOVES SOMEWHAT TO THE SOUTH AND IS NOW MOSTLY BETWEEN MUSKEGON AND GRAND HAVEN. DUAL POLE RADAR SHOWS STORM TOTALS BETWEEN 3 TO 4 INCHES HAS FALLEN IN THAT AREA. SINCE THE LATEST MODEL DATA SUGGESTS THE BAND WILL NOT START MOVING ON SHORE UNTIL AROUND 3 PM... I EXTENDED THE ADVIOSRY TILL 4 PM. UPDATE ISSUED AT 1102 AM EST WED JAN 20 2016 I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW. THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION. REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES WITH FLURRIES. UPDATE ISSUED AT 551 AM EST WED JAN 20 2016 CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY GIVEN CURRENT TRENDS: A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6 HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO WHITEHALL. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 315 AM EST WED JAN 20 2016 LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN INCH OF SNOW. THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN EFFECT UNTIL 18Z THIS AFTN. TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 315 AM EST WED JAN 20 2016 OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK. THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S. UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT THIS EARLY STAGE. THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW. RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE. FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR TRENDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1156 PM EST TUE JAN 19 2016 SNOW WILL BE ON THE INCREASE OVERNIGHT WITH WIDESPREAD IFR CONDITIONS DEVELOPING BY 12Z WEDNESDAY. EXPECT IFR AND SOME AREAS OF LIFR WEDNESDAY MORNING WITH CONDITIONS SLOWLY IMPROVING TO MVFR DURING THE AFTERNOON. WINDS WILL WEST SOUTHWEST AOB 10 KNOTS. && .MARINE... ISSUED AT 315 AM EST WED JAN 20 2016 WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF THE NEARSHORE WATERS. && .HYDROLOGY... ISSUED AT 324 PM EST TUE JAN 19 2016 WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING... HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ050- 056-064. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...HOVING AVIATION...OSTUNO HYDROLOGY...WDM MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
357 PM CST WED JAN 20 2016 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 356 PM CST WED JAN 20 2016 BIGGEST FORECAST ISSUE WILL BE SNOW AMOUNTS FOR TONIGHT. SNOW HAS BEGUN A BIT EARLIER THAN ANTICIPATED IN OUR SOUTH IN ADVANCE OF THE LONG-AWAITED APPROACHING WAVE WITHIN PROGRESSIVE FLOW. BACKED UP THE START TIME OF THE ADVISORY FOR OUR KANSAS COUNTIES TO INCLUDE THIS AFTERNOON. ALSO INCREASED SNOW AMOUNTS A BIT IN OUR SOUTH...WHICH REQUIRED THE ADDITION OF A FEW COUNTIES ON THE WESTERN EDGE OF THE WINTER WEATHER ADVISORY...TO INCLUDE WEBSTER...SMITH...AND OSBORNE COUNTIES. EXPECTING A RATHER TYPICAL 13:1 RATIO FOR LIQUID TO SNOW. FORECAST IS LARGELY ON TRACK FROM THE PREVIOUS FORECAST TONIGHT WITH MINOR CHANGES MADE IN GENERAL. SNOWFALL MAY NOT FOLLOW A SMOOTH TRANSITION FROM HEAVIER TO LIGHTER AMOUNTS FROM SOUTH TO NORTH...AS WE COULD GET A FEW CONVECTIVE BANDS TO MOVE THROUGH...AS INDICATED BY SHORT TERM MODELS SUCH AS HRRR AND RAP. ANOTHER ISSUE MAY COME LATE THURSDAY AFTERNOON WHEN WE COULD LOSE SATURATION IN THE DENDRITIC GROWTH ZONE BEFORE ALL OF THE LIGHT LINGERING PRECIPITATION EXITS. IF THIS OCCURS...THEN WE COULD GET SOME FREEZING DRIZZLE DEVELOP LATE AFTERNOON THURSDAY. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 356 PM CST WED JAN 20 2016 HAZARDOUS WX POTENTIAL: NOTHING SIGNIFICANT FORESEEN AT THIS TIME. ALOFT: SOME TEMPORARY PROGRESSION OF THE LONGWAVES WILL OCCUR AS THE PERSISTENT E PAC TROF MOVES ONSHORE SAT AND INTO THE CNTRL USA SUN- MON. THIS TROF WILL SHIFT INTO THE ERN USA BEYOND MON. THEN IT`S BACK TO THE PATTERN DOMINATING THE PAST 2 WEEKS...WITH THE E PAC TROF/WRN N AMERICA RIDGE REDEVELOPING. SURFACE: CANADIAN HIGH PRES WILL CREST OVER THE FCST AREA THU NIGHT INTO FRI. SAT THE FCST AREA WILL BE IN THE WARM SECTOR OF A CLIPPER TRACKING ACROSS SRN CANADA. LEE CYCLOGENESIS WILL ENSUE SAT NIGHT WITH THE APPROACH OF THE UPR TROF. A PAC COLD FRONT WILL SLIP THRU SUN AS THIS LOW CONTS TO ORGANIZE OVER OK/KS. WPC HAS THIS LOW OVER CNTRL MO AT 12Z/MON WHICH IS CLOSE TO THE 06Z/12Z GFS AND THE 00Z/12Z GEM. INTERESTINGLY...THE 12Z GFS ENSEMBLE MEAN IS ON THE SLOW END OF THE GUIDANCE SPREAD (OVER ERN KS/OK) WHILE THE 00Z/12Z EC AND THE 00Z ENSEMBLE MEAN ARE ON THE FASTER END OVER IA. HIGH PRES OVERTAKES THE REGION MON AND SINKS INTO THE SRN PLAINS TUE- WED. DOWNSLOPE-WARMED AIR SHOULD FLOOD THE PLAINS AS A COUPLE CLIPPERS TRACK N OF THE FCST AREA. SOME DAILY DETAILS... THU NIGHT: A LITTLE LIGHT SNOW OR FRZG DRZL COULD LINGER INTO THE EVENING HRS MAINLY HWY 81. CONFIDENCE IS LOW. OTHERWISE CLOUDY. KEPT LOW TEMPS A LITTLE ABOVE NORMAL. FRI: LOTS OF UNCERTAINTY ON DEPARTURE OF THE LOW CLOUDS...BUT THE THERMAL TROF SHIFTING E IS A GOOD SIGN. HIGH TEMPS ARE LOW CONFIDENCE. THE SNOW THAT FALLS TONIGHT WILL BE A PLAYER. SAT: INCREASING/DESCENDING MULTI-LAYERED CLOUDS...ESPECIALLY IN THE AFTERNOON. IT`S LOOKING VERY MILD...BUT AGAIN SNOW COVER A MITIGATING FACTOR. SUN: THE FCST IS CURRENTLY DRY...BUT IT`S POSSIBLE SOME LIGHT PRECIP COULD BREAK OUT IN THE AFTERNOON. NOT EXACTLY SURE ON PRECIP TYPE AS WETBULB COOLING COULD BE AN ISSUE IN THE INITIALLY DRY AIR BELOW 10K FT. THE LAST 2 RUNS OF THE OP MODELS ARE ALL OVER THE PLACE WITH VERY LIGHT QPF AND AMTS SUN NIGHT. THE 12Z GFS ENSEMBLE DOES HAVE A 30% PROBABILITY FOR .10" IN 24 HRS OVER S-CNTRL NEB. THE 12Z EC ENSEMBLE IS SIMILAR. SO THERE COULD BE A TOUCH OF LIGHT WINTRY PRECIP. MON: A LITTLE LIGHT SNOW COULD LINGER INTO THE MORNING. COLD SECTOR WITH THERMAL TROF PASSING THRU. COLDER AND PROBABLY M/CLOUDY. THE-WED: DRY AND QUIET WITH TEMPS MODERATING. && .AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1158 AM CST WED JAN 20 2016 CEILINGS AND VISIBILITY WILL CONTINUE TO BE QUITE VARIABLE AT THE BEGINNING OF THE FORECAST AS AN AREA OF STRATUS PUSHES NORTH. LOW CONFIDENCE FOR THE TIMING OF THE RETURN OF STRATUS/SNOW AS ANOTHER WINTER SYSTEM COMES INTO PLAY. A TEMPORARY WINDOW OF MVFR CONDITIONS IS EXPECTED THIS LATE AFTERNOON/EARLY EVENING BEFORE CONDITIONS DETIORATE ONCE AGAIN. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR NEZ085>087. KS...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR KSZ006-007- 018-019. && $$ SHORT TERM...HEINLEIN LONG TERM...HALBLAUB AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1153 AM CST WED JAN 20 2016 .AVIATION.../18Z TAF CYCLE/ LIFR/IFR AND MVFR CONDITIONS PERSIST ACROSS THE REGION AS OF 1745Z WITH LOW STRATUS CEILINGS REMAINING INTACT UNDERNEATH A STRONG INVERSION. KAUS IS ON THE EDGE OF THE STRATUS DECK BUT CONTINUED MVFR CIGS WILL CONTINUE TO MOVE IN FROM THE SOUTH THROUGH THE AFTERNOON. KSAT/KSSF/KDRT ARE NOT EXPECTED TO IMPROVE MUCH FURTHER THAN CURRENT CONDITIONS THROUGH THE AFTERNOON AS WELL. NAM BUFR SOUNDINGS ALONG WITH LAMP GUIDANCE AND HRRR OUTPUT ALL SUPPORT WORSENING FLIGHT CATEGORIES THIS EVENING STARTING NEAR OR AFTER 04Z. EXPECT IFR/LIFR CONDITIONS AT ALL SITES WITH SOME POSSIBLE/LIKELY POCKETS OF VLIFR WITH VISIBILITY RESTRICTIONS OCCURRING DOWN TO 1/2 SM AT TIMES DUE TO LOW CLOUDS/FOG. LOW LEVEL SATURATION MAY EVEN BE GREAT ENOUGH FOR -DZ TO OCCUR AS WELL. CIGS/VIS WILL REMAIN LOW THROUGH THURSDAY MORNING TILL 15-18Z BEFORE A CLEARING FRONT MOVES THROUGH. CONDITIONS SHOULD RAPIDLY IMPROVE WITH THE PASSAGE OF THE FRONT THURSDAY AFTERNOON /21Z/ TO VFR. SURFACE WINDS WILL BE WEAK THIS AFTN AND OVERNIGHT AT 10 KT OR LESS FROM THE NORTH AND BECOMING EAST TO SOUTHEAST AHEAD OF THE FRONT. WINDS WILL REALLY INCREASE ALONG AND BEHIND THE FRONT TO THE WNW AT 15-20 WITH GUSTS TO 30 KT THURSDAY AFTN. WILL PLACE MORE FOCUS ON WINDS IN SUBSEQUENT TAF ISSUANCES. && .PREV DISCUSSION... /ISSUED 1043 AM CST WED JAN 20 2016/ UPDATE... THE COLD FRONT HAS MOVED SOUTH OF OUR CWA AND IN ITS WAKE LEFT CLOUDY SKIES OVER SOUTH CENTRAL TEXAS. SURFACE WIND ARE LIGHT FROM THE NORTH. THIS COMBINATION IS KEEPING TEMPERATURES DOWN AND WE HAVE LOWERED THE HIGHS FOR TODAY. THE REST OF THE FORECAST LOOKS TO BE IN GOOD SHAPE AND HAVE ONLY ADJUSTED HOURLY GRIDS TO ACCOUNT FOR OBSERVATIONAL TRENDS. PREV DISCUSSION... /ISSUED 427 AM CST WED JAN 20 2016/ SHORT TERM (TODAY THROUGH THURSDAY)... THE LEADING EDGE OF A WEAK COLD FRONT EXTENDING FROM A SURFACE LOW PRESSURE SYSTEM OVER SW ARKANSAS HAS ENTERED THE I-35 CORRIDOR AND WILL CONTINUE TO PUSH TOWARDS THE GULF COAST OVER THE NEXT FEW HOURS. ALTHOUGH THIS HAS RESULTED IN A NORTHERLY WIND SHIFT...COLD AIR ADVECTION AT H850-925 IS WEAK AS THE TEMPERATURE GRADIENT IS BECOMING NEARLY PARALLEL TO THE WIND. SHOWERS ASSOCIATED WITH THE FRONT AND A WEAK SHORTWAVE BRIEFLY FORMED OVER WILLIAMSON COUNTY AND EAST TOWARDS COLLEGE STATION AND ARE ATTEMPTING TO REFORM IN FAYETTE COUNTY EAST OF LA GRANGE. HOWEVER...THE SURFACE POTENTIAL TEMPERATURE AND ASSOCIATED DENSITY GRADIENT CONTINUES TO WEAKEN WHICH SHOULD ALLOW FOR ONLY VERY ISOLATED SHOWERS. PATCHY FOG MAY DEVELOP AHEAD OF THE FRONT IN THE COASTAL PLAINS OVER THE NEXT FEW HOURS AND IN THE RIO GRANDE PLAINS THROUGH MID-MORNING WHERE THE BOUNDARY WILL BE MOST DIFFUSE AND EVENTUALLY BECOME STATIONARY. MODELS ARE GENERALLY IN GOOD AGREEMENT THAT THE FRONT WILL STALL ALONG THE RIO GRANDE PLAINS INTO SOUTH TEXAS AND THE UPPER GULF COAST. SW-NE ORIENTED ISENTROPIC ASCENT WILL SET UP OVER SOUTH CENTRAL TEXAS TODAY TO CAUSE MOSTLY CLOUDY TO OVERCAST SKIES THAT WILL LIMIT DAYTIME HEATING...THOUGH LOW LEVEL WARM AIR ADVECTION SHOULD ALLOW HIGHS TO REACH THE MID TO UPPER 60S OVER THE SOUTHERN ZONES...WHILE STRUGGLING TO REACH 60 DEGREES OVER OUR NORTHERN ZONES. THIS WEAKLY DEFINED WARM FRONTAL BOUNDARY WILL PROGRESS TO THE NORTHEAST WEDNESDAY EVENING AS ANOTHER SURFACE LOW DEVELOPS OVER NORTH TEXAS IN RESPONSE TO A DIGGING AND INTENSIFYING UPPER LEVEL TROUGH. THIS WILL KEEP THE REGION IN THE WARM SECTOR OF THE SURFACE LOW AND ALLOW FOR MOSTLY CLOUDY SKIES AND POSSIBLY SOME PATCHY ADVECTION FOG THAT WILL KEEP LOWS IN THE 40S AND 50S. THE SURFACE LOW AND UPPER LEVEL TROUGH IN THE EURO CONTINUES TO TRACK FURTHER SW THAN THE GFS...WHICH DEPICTS A DEEPER SYSTEM FURTHER TO THE NE AND KEEPS MOST PRECIP OUT OF OUR AREA. EXTENDED HI-RES MODEL RUNS AND THE NAM ARE CLOSER TO THE GFS...AND ALL MODELS TAKE A COLD FRONT THROUGH THE REGION BY 18Z THURSDAY...SO HAVE CONTINUED TO KEEP PRECIP CHANCES LOW AND CONFINED TO OUR NE COUNTIES. MOST MODELS SHOW THERE IS A SMALL AMOUNT OF SURFACE BASED INSTABILITY...SO ISOLATED THUNDERSTORMS WOULD BE POSSIBLE SHOULD THE TRACK OF THE SYSTEM SIMULATED BY THE EURO VERIFY. HOWEVER...ELEVATED FIRE WEATHER CONDITIONS IN THE RIO GRANDE PLAINS ARE A GREATER CONCERN ON THURSDAY AFTERNOON AS MIN RH VALUES IN THE LOWER 20S AND WINDS SUSTAINED TO 25 KNOTS AND GUSTING ABOVE 30 KNOTS PERSIST BEHIND THE FRONT. THE HIGH TEMPERATURE FORECAST...AND ASSOCIATED RH FORECAST...IS FAIRLY TRICKY ON THURSDAY AS STRONG COLD AIR ADVECTION WILL BE GOING AGAINST THE EFFECTS OF DAYTIME RADIATIONAL HEATING AND DOWNSLOPING WINDS. IT CURRENTLY LOOKS LIKE THE COLD AIR ADVECTION WILL WIN OUT OVER OUR NORTHERN ZONES WHERE HIGHS WILL BE IN THE LOWER TO MID 60S WHILE THE LATTER EFFECTS MAY WIN OUT OVER OUR SOUTHERN ZONES AND RIO GRANDE PLAINS WHERE HIGHS WILL BE IN THE LOWER 70S. LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)... STRONG 15-20 KNOT WIND GUSTS WILL CONTINUE THURSDAY NIGHT INTO FRIDAY AS THE REGION REMAINS ON THE BACKSIDE OF A DEEPENING CYCLONE OVER THE LOWER MISSISSIPPI VALLEY. THIS STRONGER N-NW FLOW WILL KEEP HIGHS IN THE LOWER 50S OVER OUR NORTHERN AND EASTERN ZONES...WHILE REMAINING IN THE LOWER 60S OVER THE RIO GRANDE PLAINS WHERE THESE EFFECTS WILL BE WEAKER. CALM WINDS AND HIGH PRESSURE OVERNIGHT FRIDAY INTO SATURDAY WILL ALLOW FOR LOWS IN THE UPPER 20S IN THE HILL COUNTRY WITH A LIGHT FREEZE FOR MOST AREAS ALONG AND NORTH OF HIGHWAY 90/INTERSTATE 10. SOUTHERLY WINDS RETURN ON SATURDAY WITH WARMER THAN NORMAL TEMPERATURES IN THE UPPER 60S AND LOWER 70S RETURNING ON SUNDAY AS UPPER LEVEL RIDGING TAKES PLACE AHEAD OF OUR NEXT COLD FRONT THAT MOVES THROUGH ON MONDAY. LOW MOISTURE LEVELS AND WEAK DYNAMIC FORCING WITH THIS FRONT MAKES SHOWERS UNLIKELY ON MONDAY...WITH SLIGHTLY COOLER THAN NORMAL TEMPERATURES AND DRY AIR MOVING IN FOR TUESDAY BEHIND THE FRONT. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 66 39 53 32 / 20 20 0 0 0 AUSTIN BERGSTROM INTL AIRPORT 51 67 37 53 30 / 20 20 0 0 0 NEW BRAUNFELS MUNI AIRPORT 52 69 38 56 31 / 10 20 0 0 0 BURNET MUNI AIRPORT 49 62 35 52 30 / 10 20 0 0 0 DEL RIO INTL AIRPORT 46 69 37 62 34 / - 0 0 0 0 GEORGETOWN MUNI AIRPORT 50 63 37 51 29 / 20 20 0 0 0 HONDO MUNI AIRPORT 49 70 37 60 30 / - 10 0 0 0 SAN MARCOS MUNI AIRPORT 52 67 38 55 31 / 10 20 0 0 0 LA GRANGE - FAYETTE REGIONAL 56 68 39 54 32 / 20 30 - 0 0 SAN ANTONIO INTL AIRPORT 53 70 39 58 33 / 10 10 0 0 0 STINSON MUNI AIRPORT 53 71 39 59 33 / 10 10 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...ALLEN SYNOPTIC/GRIDS...05
AREA FORECAST DISCUSSION
NWS SEATTLE WA
258 PM PST WED JAN 20 2016 .SYNOPSIS...A SLOW MOVING FRONTAL SYSTEM WILL BRING RAIN TO WESTERN WASHINGTON TONIGHT THROUGH FRIDAY MORNING. THE FRONT WILL MOVE EAST FRIDAY AFTERNOON WITH RAIN CHANGING TO SCATTERED SHOWERS. AN UPPER LEVEL LOW OVER OREGON WILL BRUSH THE AREA WITH A LITTLE RAIN ON SATURDAY. AN UPPER LEVEL RIDGE JUST OFFSHORE WILL BRING DRIER WEATHER SUNDAY AND MONDAY BUT A FEW SHOWERS MAY STILL BE AROUND. ANOTHER FRONTAL SYSTEM SHOULD REACH THE AREA MONDAY NIGHT OR TUESDAY. && .SHORT TERM...HIGH CLOUDS FROM AN APPROACHING WET FRONTAL SYSTEM HAVE MOVED OVER W WA THIS AFTERNOON. RAIN IS NOT FAR BEHIND AS RADAR IS PICKING UP A BAND OF RAIN TO THE SW HEADED TOWARD THE S WA COAST. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THE ADVANCING RAIN... BRINGING IT TO THE CENTRAL COAST AROUND 01Z/5 PM AND TO PUGET SOUND AROUND 04Z/8 PM. THE WARM FRONT FROM THIS SYSTEM WILL BRING STRONG WARM ADVECTION WITH 40-60 KT S-SW WINDS ALOFT FROM 925MB-850MB TO W WA LATER TONIGHT AND THURSDAY. THIS STRONG S-SW FLOW WILL CONTINUE THURSDAY NIGHT AS THE SLOW MOVING COLD FRONT APPROACHES. THIS WILL PRODUCE HEAVY RAIN OVER THE OLYMPICS AND N CASCADES TONIGHT THROUGH THURSDAY NIGHT. THE SYSTEM WILL WEAKEN FRIDAY MORNING AS THE COLD FRONT MOVES INLAND. TOTAL PRECIP OVER THE AREA TONIGHT THROUGH FRIDAY MORNING WILL BE AROUND 3-6 INCHES OVER THE OLYMPICS AND N CASCADES WITH 0.50- 1.00 OVER THE INTERIOR LOWLANDS. SNOW LEVELS WILL RISE TO NEARLY 7500 FEET BY MIDDAY THURSDAY. WEAK AND COOL EASTERLY FLOW THROUGH THE CASCADE PASSES SHOULD ALLOW SEVERAL INCHES OF LIGHT SNOW TO FALL TONIGHT INTO THURSDAY MORNING...BUT THE STRONG WARMING ALOFT WILL PROBABLY OVERWHELM THE COOL EAST LOW LEVEL FLOW FOR A CHANGE OVER TO RAIN BEFORE MIDDAY THURSDAY. WINDY CONDITIONS WILL DEVELOP OVER MAINLY THE COAST AND N INTERIOR TONIGHT AND THURSDAY AS THE SYSTEM MOVES OVER THE AREA. THE COLD FRONT WILL FINALLY BE PUSHED INLAND FRIDAY MORNING ALLOWING THE RAIN TO TAPER OFF WITH A CHANGE TO SHOWERS IN THE AFTERNOON. A WEAK UPPER LEVEL RIDGE WILL MOVE OVER THE AREA FRIDAY AFTERNOON FOR A LITTLE DRYING. THE LAST COUPLE OF MODEL RUNS HAVE CHANGED FOR SATURDAY. THE LATEST SOLUTIONS NOW FORM A CLOSED LOW W OF THE N CA COAST ON FRIDAY...THEN SWING IT NE TO ABOUT THE CENTRAL OREGON COAST SATURDAY MORNING. INCREASING S FLOW ALOFT AHEAD OF THE LOW NOW SPREADS LIGHT RAIN NORTHWARD ACROSS W WA SATURDAY MORNING. THE 18Z GFS IS EVEN A LITTLE FASTER THAN THE 12Z GFS SO LIGHT RAIN MIGHT EVEN MAKE IT UP TO PUGET SOUND A LITTLE BEFORE SUNRISE. RAIN WILL DIMINISH SATURDAY EVENING AS THE SYSTEM MOVES E. KAM .LONG TERM...MODEL SOLUTIONS ARE STILL EVOLVING FROM RUN-TO-RUN IN THE EXTENDED PERIOD. AN UPPER LEVEL RIDGE JUST OFFSHORE SATURDAY EVENING WILL EVENTUALLY MOVE OVER W WA MONDAY MORNING. THE 12Z GFS WAS DRIER DURING THIS PERIOD...BUT NOW THE 18Z RUN HAS SHIFTED BACK TO A PREVIOUS SOLUTION WHERE A SHORTWAVE TROUGH PUSHES THROUGH THE RIDGE THEN BRINGS SOME SHOWERS TO THE AREA. FOR NOW...WITH LOW CONFIDENCE IN THE MODEL SOLUTIONS I WILL KEEP A BROADBRUSH CHANCE OF SHOWERS SUNDAY AND MONDAY. MODELS HAVE BEEN BRINGING ANOTHER FRONTAL SYSTEM TO THE AREA EARLY NEXT WEEK. EARLIER RUNS HAD IT ON MONDAY WHILE THE 18Z GFS HOLDS OFF UNTIL MONDAY NIGHT AND TUESDAY. ANOTHER FRONTAL SYSTEM MAY ARRIVE LATE WEDNESDAY. KAM && .AVIATION...SOUTHWESTERLY FLOW ALOFT WILL CONTINUE TONIGHT AND THURSDAY AS A FRONT STALLS NEAR THE COAST. SURFACE GRADIENTS WILL BECOME INCREASINGLY SOUTHEASTERLY. THE AIR MASS IS STABLE WITH INCREASING MOISTURE ALL LEVELS. RAIN WILL BEGIN ON THE COAST AROUND 01Z AND SPREAD INLAND BY 04Z OR SO. CONDITIONS ARE GOOD VFR OVER MOST OF THE AREA EXCEPT FOR A PATCH OF MVFR CEILINGS AROUND THE STRAIT OF JUAN DE FUCA. CEILINGS WILL LOWER TONIGHT AS THE FRONT APPROACHES AND BY THE TIME RAIN BEGINS THEY WILL BE 3-5K FT. SEVERAL HOURS OF MVFR CEILINGS ARE LIKELY LATE TONIGHT AND THURSDAY MORNING. KSEA...DISCUSSION ABOVE APPLIES. SOUTHEAST WIND 5-10 KT WILL BECOME MORE EASTERLY TONIGHT...THEN SOUTHEAST 10-15 KT AFTER 12Z THURSDAY. CHB && .MARINE...A STRONG FRONT WILL MOVE INTO THE COASTAL WATERS THIS EVENING AND THEN SLOWLY MOVE INLAND TONIGHT AND THURSDAY. GALE WARNINGS ARE IN EFFECT FOR THE COAST..THE CENTRAL AND EASTERN STRAIT...AND THE NORTHERN INLAND WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE REMAINING WATERS. WINDS WILL EASE THURSDAY NIGHT AND ARE LIKELY TO REMAIN BELOW 20 KT FRIDAY AND SATURDAY. ANOTHER FRONT MAY APPROACH THE COAST SUNDAY. CHB && .HYDROLOGY...ANOTHER 3 TO 6 INCHES OF PRECIPITATION WILL FALL OVER THE OLYMPICS AND NORTH CASCADES TONIGHT THROUGH THURSDAY NIGHT...WITH THE SNOW LEVEL RISING TO 6500 TO 7500 FT. THIS WILL PUSH THE SKOKOMISH RIVER BACK ABOVE FLOOD STAGE AGAIN PROBABLY SOMETIME THURSDAY MORNING. THE ONLY REAL QUESTION IS WHETHER OR NOT IT WILL REACH ITS MAJOR FLOOD STAGE. THE FLOOD WATCH WILL REMAIN IN EFFECT. OTHER WESTERN WASHINGTON RIVERS FLOWING OFF THE OLYMPICS AND THE NORTH CASCADES WILL ALSO RISE SIGNIFICANTLY. HOWEVER NORTHWEST RIVER FORECAST CENTER GUIDANCE SHOWS MOST OF THESE RIVERS...THE SATSOP... ELWHA...DUNGENESS...SKAGIT...AND STILLAGUAMISH...CRESTING AT MOST WITH AROUND 70 PERCENT OF THE DISCHARGE NEEDED TO REACH FLOOD STAGE. SO THE THREAT ON THESE RIVERS LOOKS PRETTY LOW. THE GUIDANCE FOR THE NOOKSACK SHOWS IT GETTING CLOSEST TO FLOOD STAGE...THE SOUTH FORK NOOKSACK SPECIFICALLY...BUT STILL LESS THAN 80 PERCENT OF THE DISCHARGE CORRESPONDING TO FLOOD STAGE. WITH FLOODING NOT EXPECTED ON ANY RIVERS OTHER THAN THE SKOKOMISH... THE FLOOD POTENTIAL OUTLOOK WILL BE ALLOWED TO EXPIRE THIS AFTERNOON. OTHERWISE...RIVER FLOODING IS NOT EXPECTED THE NEXT 7 DAYS. KAM && .SEW WATCHES/WARNINGS/ADVISORIES... WA...FLOOD WATCH FROM THIS EVENING THROUGH LATE FRIDAY NIGHT FOR HOOD CANAL AREA-LOWER CHEHALIS VALLEY AREA-OLYMPICS. PZ...SMALL CRAFT ADVISORY COAST UNTIL 4 PM PST THIS AFTERNOON. GALE WARNING COAST...CENTRAL AND E STRAIT AND NORTH INLAND WATERS FROM 4 PM THIS AFTERNOON TO 7 PM PST THURSDAY. SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 7 PM PST THURSDAY FOR GRAYS HARBOR BAR. SMALL CRAFT ADVISORY UNTIL 4 PM PST THURSDAY FOR PUGET SOUND AND HOOD CANAL-WEST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA. SMALL CRAFT ADVISORY UNTIL 7 PM PST THURSDAY FOR ADMIRALTY INLET. && $$ WWW.WEATHER.GOV/SEATTLE YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS PORTLAND OR
257 PM PST WED JAN 20 2016 .SYNOPSIS...A WARM FRONT WILL MOVE ONTO THE COAST LATE THIS AFTERNOON AND INLAND TONIGHT...AND SNOW LEVELS WILL RISE WELL ABOVE THE CASCADE PASSES. THE TRAILING COLD FRONT WILL MOVE INLAND THURSDAY NIGHT AND FRIDAY. A LOW WILL APPROACH FROM THE SOUTHWEST FRIDAY NIGHT AND SATURDAY FOR MORE RAIN AND CASCADE SNOW. SNOW LEVELS WILL LOWER BACK DOWN TO NEAR THE CASCADE PASSES OVER THE WEEKEND. THE PROGRESSIVE WEATHER PATTERN WILL CONTINUE PERIODS OF RAIN AND CASCADE SNOW INTO NEXT WEEK. && .SHORT TERM...RAIN SHOWERS HAS ENDED TO THE NORTH...BUT THE NEXT BAND OF RAIN ASSOCIATED WITH A WARM FRONT IS JUST BEGINNING TO REACH THE CENTRAL OREGON COAST. A LARGE HIGH CLOUD SHIELD IS MAKING IT DIFFICULT TO SEE ON SATELLITE IMAGERY WHERE THE ACTUAL FRONT IS THIS AFTERNOON. THE OFFSHORE BUOYS SHOW SE WINDAND DECREASING PRESSURE SUGGESTING THE FRONT IS STILL QUITE A WAYS OFFSHORE. THERE HAS BEEN A SMALL AREA OF LIGHTNING STRIKES AROUND 42N 130 W THAT MAY BE ASSOCIATED WITH A FRONTAL BOUNDARY OR A LOW CENTER...BUT IT IS HARD TO CURRENTLY TELL. THE TALE END OF THIS WARM FRONT WILL BRUSH OVER THE REGION LATE THIS AFTERNOON THROUGH LATE TONIGHT. RAIN WILL MOSTLY BE NORTH OF SALEM...AND ACROSS THE HIGHER TERRAIN...WITH AROUND 0.5 INCH OF RAIN FOR FOR THE NORTHERN CASCADES AND NORTHERN COAST RANGE...AND 0.05 TO 0.15 INCH FOR THE INTERIOR LOW LANDS NORTH OF SALEM. EXPECT VERY LITTLE MEASURABLE RAIN...LESS THAN 0.05 INCH FOR NON-COASTAL AREAS SOUTH OF SALEM. SNOW LEVELS WILL RAPIDLY RISE THIS EVENING WITH THE PASSAGE OF THE WARM FRONT AND BE AROUND 7000 FEET LATE TONIGHT. THE HIGHER VALLEYS IN THE SOUTH WASHINGTON CASCADES WILL HAVE A SLIGHT CHANCE FOR FREEZING RAIN TONIGHT AND EARLY THURSDAY. A BUILDING UPPER LEVEL RIDGE OVER THE PACIFIC NW WILL SLOW THE PROGRESS OF THE COLD FRONT WHICH IS CURRENTLY BETWEEN 130W AND 140W...AND THE FRONT SHOULD STALL JUST OFF OF THE OREGON AND WASHINGTON COAST THURSDAY. THE COAST WILL LIKELY SEE CONTINUOUS RAIN BETWEEN THE WARM AND COLD FRONT...BUT MOST INTERIOR AREAS WILL HAVE A BREAK IN THE RAIN LATE THURSDAY MORNING THROUGH EARLY FRIDAY....BEFORE THE COLD FRONT MOVE INLAND THURSDAY NIGHT AND FRIDAY MORNING. THE FRONT WILL SPLIT OFFSHORE BEFORE IT PUSHES INLAND SENDING THE HEAVIEST RAINFALL SOUTH OF OREGON...BUT STILL EXPECT A FEW HOURS OF HEAVY RAIN WITH THE FRONT PASSAGE EARLY FRIDAY MORNING FOR THE COAST AND COAST RANGE AND MID MORNING TO EARLY AFTERNOON EAST OF THE COAST RANGE.SNOW LEVELS WILL REMAIN HIGH...ABOVE 7000 FEET. THE COAST AND COAST RANGE WILL SEE THE MOST RAIN WHERE 0.75 TO 1.25 INCHES OF RAIN IS EXPECTED THURSDAY EVENING THROUGH FRIDAY MORNING. OTHER AREAS CAN EXPECT 0.35 TO 0.70 INCHES OF RAIN. WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL SHORT WAVE DEEPENING SOUTH OF THE ALEUTIAN ISLANDS NEAR 46N 161W. THIS TROUGH WILL SPLIT FROM THE PARENT UPPER LEVEL TROUGH AS IT MOVES SW ACROSS THE PACIFIC ON THURSDAY AND FORM A CUT OFF LOW OFFSHORE OF NORTHERN CALIFORNIA FRIDAY AFTERNOON. THE LOW WILL THEN SEND A WARM FRONT ACROSS NW OREGON AND SW WASHINGTON FRIDAY NIGHT AND SATURDAY AS THE LOW MOVES INLAND NEAR THE OREGON/CALIFORNIA BORDER...FOR MORE RAIN AND CASCADE SNOW. SNOW LEVELS WILL BE AROUND 4500 FEET. TJ .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY. LITTLE CHANGE TO THE FORECAST AS MODELS REMAIN IN REASONABLY GOOD AGREEMENT THROUGH THE PERIOD. UPPER TROUGH SLIDES EAST OF THE CASCADES BY LATE SATURDAY NIGHT WITH RESIDUAL SHOWERS TAPERING OFF AS SHORTWAVE RIDGING BUILDS OVER THE REGION IN BETWEEN SYSTEMS. MODELS SUGGEST THE NEXT DISTURBANCE MAY SPLIT OFFSHORE AS IT APPROACHES OVERNIGHT SUNDAY...PERHAPS BRINGING SOME LIGHT RAIN AT TIMES...PARTICULARLY IN SW WASHINGTON...BUT IN LIMITED AMOUNTS. MONDAY MAY BE DRY AS UPPER LEVEL RIDGE AXIS MOVES OVER THE AREA...BUT THE NEXT FRONT WILL ARRIVE TUESDAY FOR ANOTHER ROUND OF PRECIPITATION. THIS WILL BE IN THE FORM OF RAIN FOR MOST LOCATIONS AS SNOW LEVELS WILL RISE ABOVE 6000 FEET BY LATE MONDAY BEFORE THE BULK OF THE MOISTURE ARRIVES. && .AVIATION...A WARM FRONT TO LIFT NORTH THROUGH THE REGION LATER THIS AFTERNOON AND EVENING. THIS WILL BRING INCREASING LIGHT RAIN AND LOWERING CIGS...ALTHOUGH CONDITIONS SHOULD REMAIN MOSTLY VFR WITH CIG HEIGHTS AT 4 TO 5 KFT. LIGHT RAIN TO CONTINUE OVERNIGHT...MAINLY FOR THE COAST AND NORTHERN INTERIOR. CIGS IN THESE AREAS MAY DROP DOWN TO AROUND 3 KFT BETWEEN 06Z AND 12Z THU. INLAND AREAS FROM ROUGHLY KSLE SOUTH EXPECTED TO BE MOSTLY DRY OVERNIGHT AND REMAIN VFR. HAVE WIND SHEAR CONCERNS AFTER 12Z FOR KTTD AND KPDX AS SURFACE FLOW WILL BE EASTERLY FROM THE GORGE WHILE FLOW ALOFT WILL INCREASE FRONT THE SOUTH. KPDX AND APPROACHES...LIGHT RAIN BEGINS AND CIGS LOWER TO AROUND 5 KFT THIS EVENING AS WARM FRONT MOVES THROUGH THE REGION. LIGHT RAIN WILL LIKELY CONTINUE MUCH OF THE NIGHT...WITH CIGS LOWERING FURTHER TO AROUND 3 TO 4 KFT. EXPECT LITTLE CHANGE THROUGH THE DAY THU. EAST FLOW WILL INCREASE AFTER 09Z THU AND BRING LLWS CONCERNS FROM ABOUT 12Z THEREAFTER. PYLE && .MARINE...STRONG OCCLUDING LOW PRES NEAR 50N/145W THIS AFTERNOON. THIS SYSTEM WILL BRING A WARM FRONT THROUGH THE WATERS LATER THIS AFTERNOON AND THIS EVENING. GUSTY SOUTHERLY WINDS TO INCREASE THIS EVENING AS WELL...WITH GUSTS 40 TO 45 KT EXPECTED OVER THE OUTER WATERS WHERE A GALE WARNING IS NOW IN EFFECT. THE PRES GRADIENT TO REMAIN FAIRLY OFFSHORE...SO THINK WINDS WILL NOT BE QUITE AS STRONG OVER THE NEAR SHORE WATERS. THINK A SMALL CRAFT ADVISORY WILL BE SUFFICIENT. THE STRONG SOUTHERLY WINDS TO CONTINUE THROUGH THU. A TRAILING COLD FRONT TO MOVE THROUGH THE WATERS LATE THU NIGHT INTO EARLY FRI MORNING. EXPECT WINDS TO SWITCH TO SOUTHWESTERLY AND DROP OFF CONSIDERABLY BEHIND THE FRONTAL PASSAGE. ANOTHER LOW PRES SYSTEM TO APPROACH THE S OREGON COAST FRI NIGHT INTO SAT...BUT CURRENTLY EXPECT THIS SYSTEM WILL NOT HAVE MUCH IMPACT FOR THE S WASHINGTON AND N OREGON COASTAL WATERS. HIGH PRES BUILDS OVER THE WATERS FOR THE LATE WEEKEND AND EARLY NEXT WEEK. SEAS HAVE CONTINUED TO BE A FOOT OR TWO LOWER THAN GUIDANCE...BUT REMAIN IN THE LOW TEENS. WILL SEE SEAS INCREASE LATER THIS AFTERNOON AND THIS EVENING AS WINDS PICK UP...BUILDING INTO THE MID TEENS TONIGHT AND LIKELY PEAKING IN THE UPPER TEENS LATE THURSDAY. SEAS SUBSIDE BACK TO THE MID TEENS BY FRIDAY AND LOOK TO FALL BELOW 10 FT SOMETIME THIS WEEKEND. PYLE && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...GALE WARNING UNTIL 10 PM PST THURSDAY FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM. SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST THURSDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 10 NM. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST THURSDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 10 NM. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM PST THURSDAY. && $$ INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/NWSPORTLAND WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
  [top] Area Forecast Discussion National Weather Service Spokane WA 242 PM PST WED JAN 20 2016 .SYNOPSIS... A slow moving frontal system will bring locally heavy snow to the Cascades and the Methow Valley tonight into Thursday. The front will gradually move through eastern Washington and north Idaho on Friday bringing light rain. Saturday will also feature the potential for rain and mountain snow. High pressure should produce mainly dry conditions Sunday and Monday before more valley rain and mountain snow returns Tuesday. && .DISCUSSION... ...HEAVY MOUNTAIN SNOW AND WINTRY MIX EAST SLOPES OF CASCADES TONIGHT THROUGH FRIDAY MORNING... Tonight through Friday morning: Satellite imagery shows the next weather system knocking on our doorstep. The upper level low pressure circulation is located out at 50N 135W in the Gulf of Alaska. This low pressure system is tapping into a sub-tropical moisture plume that extends out to the Hawaiian Islands. The upper level trough will continue to dig as it approaches the region. This will act to orient the moisture plume more meridionally more along the western coast line. The warm front currently pushing its way into northwest OR with light rain being observed on radar along the coast. This front is progged to reach the northern Cascades between 8:00 and 10:00 PM this evening based off the latest HRRR guidance. Much of the region will see at least a chance for some light precipitation as the front crosses eastern WA and into the ID Panhandle overnight. A southeasterly pressure gradient will strengthen overnight. This will result in some downsloping off of the Northeast Blue Mtns and off of the higher terrain in the ID Panhandle. I anticipate that that this will act to hinder much precipitation from actually reaching the ground across the Palouse, into the Lewiston- Clarkston Vly and up on the Camas Prairie. Generally only some light precipitation is anticipated with the warm front across much of eastern WA and in the ID Panhandle. Areas that will benefit from the easterly gradient will be the East Slopes of the Northern Cascades. The combination of moist isentropic ascent and orographics should keep these areas wet. Snow levels are going to be very tricky with this system. Valleys that saw some sun across this area this afternoon should have a difficult time cooling back down below freezing overnight. Higher clouds are already moving in and this should act to keep this warmer air from radiating completely away. However, the Okanogan Valley and Methow Valley continue to see low clouds, which has kept their temperatures down in the low 30s. These locations will see a better chance for accumulating snow; although, I am not as confidence about the Okanogan Valley. I think surface temperatures will be too warm for much of the Wenatchee Area for snow to stick, especially right along the Columbia River. I also think that Wenatchee River Valley, Entiat River Valley and communities along Lake Chelan will have a difficult time seeing snow accumulate. The Winter Storm Watch will be upgraded to a Warning for heavy snow, but will largely only includes locations below 3000 feet south of Lake Chelan. The upper reaches of the Methow Valley will also see a good chance for heavy snow accumulations. The warning will run from tonight and continue into Friday morning until the cold front passes through. I also kept a possibility for freezing rain in the east slopes of the northern Cascades and colder pockets in the Wenatchee Area. My confidence is low since way did see some warming today, but cannot completely rule it out. /SVH Friday: The frontal system hung up along the Cascades Thursday and Thursday night will finally be shoved eastward on Friday. There will be a good deal of deep layer moisture accompanying the front as it moves through eastern Washington and north Idaho, but not a lot of large scale forcing. The models hardly depict a surface low with the weak 500mb shortwave trough...an indication of weak forcing. So despite an abundance of moisture, precipitation amounts will be relatively light compared to some of our recent storm systems. Snow levels will be high Friday and Friday night with lowland communities region-wide receiving rain. One area of exception could be the Methow Valley where the NAM and GFS depict a bit of cooler air trapped along the Cascades which could contribute to light snow accumulations Friday morning. Saturday and Sunday: Saturday has the potential to be cool and wet as a weakening upper low moves into Oregon and falls apart. The GFS and Canadian models sustain a weak deformation band Saturday into Saturday night which produces a tenth to a quarter of an inch or precipitation for eastern Washington and north Idaho. The NAM and ECMWF split this feature suggesting lower precipitation chances for our region Saturday. This system bears watching since snow levels will be marginal for accumulations in the lee of the Cascades into portions of Washington and Idaho near the Canadian border. However, given the daytime arrival of precipitation, snow may struggle to accumulate on roads. There is good model agreement that Sunday will be drier with orographic snow showers mainly limited to the mountains of the Idaho Panhandle. The sun may even make an appearance Sunday along the east slopes of the Cascades into portions of the Columbia Basin. /GKoch Sunday night through Wednesday...Models are in good agreement of an upper level ridge over the region Sunday night through Monday night. This should result in dry conditions with areas of low clouds and patchy fog in the valleys and Columbia Basin. The ridge moves east on Tuesday allowing a weak short wave trough to pass through the Inland NW bringing with it a chance for light rain and snow. GFS Ensembles show quite a bit of spread regarding the timing of this wave and would not be surprised to see the timing delayed until Tuesday night or Wednesday. Models then show a milder and wetter system for next Wednesday or Thursday. Near to slightly above normal temperatures are expected in the extended forecast period. JW && .AVIATION... 18Z TAFS: The main aviation concern for the rest of today will be fog and low stratus. Satellite imagery shows much of these low clouds banked up along the periphery of the upper Columbia Basin. This will continue to impact the KGEG, KSFF and KCOE TAF sites as well as extend up the Okanogan Valley and valleys across NE WA and into the ID Panhandle with IFR/MVFR conditions. KPUW should see improving cigs through the morning and is expected to scatter out in the afternoon. Easterly winds are also expected to scatter out the Spokane/Coeur d`Alene corridor this evening. The focus will then shift across the east slopes of the Cascades for tonight. A warm front will increase precip chances at KEAT after 08Z. This precip is expected to begin as snow and should be very wet with surface temps right around freezing. A warm tongue moving in aloft will then increase the possibility for freezing rain early Thursday morning, but there is uncertainty if surface temps will be below freezing. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 34 42 36 42 33 39 / 20 50 20 60 40 50 Coeur d`Alene 33 41 35 42 33 39 / 10 50 20 70 50 50 Pullman 35 46 38 46 34 40 / 10 20 10 60 40 50 Lewiston 36 51 41 50 37 44 / 10 20 10 30 30 50 Colville 32 39 34 40 33 37 / 30 80 50 60 40 40 Sandpoint 32 38 35 40 33 38 / 20 60 20 80 60 50 Kellogg 31 40 36 40 31 36 / 10 40 20 70 60 60 Moses Lake 34 43 34 44 32 40 / 30 50 30 40 20 50 Wenatchee 34 39 35 42 31 37 / 90 90 80 90 20 50 Omak 32 36 33 39 29 35 / 70 100 80 90 20 40 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Winter Storm Warning from 10 PM this evening to 10 AM PST Friday for East Slopes Northern Cascades. && $$
AREA FORECAST DISCUSSION
NWS SEATTLE WA
840 AM PST WED JAN 20 2016 .SYNOPSIS...AN UPPER LEVEL RIDGE WILL BRING DRIER WEATHER TO WESTERN WASHINGTON TODAY WITH A FEW SUN BREAKS. A FRONTAL SYSTEM WILL MOVE SLOWLY ACROSS THE REGION TONIGHT THROUGH THURSDAY NIGHT...FOR A PERIOD OF WET WEATHER. THE FRONT WILL MOVE EAST FRIDAY...AND A WEAK UPPER LEVEL TROUGH WILL BE OVER THE AREA THIS WEEKEND. ANOTHER FRONT SHOULD ARRIVE EARLY NEXT WEEK. && .SHORT TERM...A WEAK UPPER LEVEL RIDGE CENTERED JUST OFFSHORE AT 16Z/8 AM THIS MORNING WILL MOVE OVER W WA THIS AFTERNOON. AS EXPECTED SOME RESIDUAL SHOWERS REMAIN OVER THE AREA. HRRR AND 12Z GFS AGREE THAT THE SHOWERS SHOULD DISSIPATE BY AROUND MIDDAY. THE LEADING EDGE OF AN APPROACHING WET FRONTAL SYSTEM WAS JUST OFFSHORE THIS MORNING WITH THE COLD FRONT OUT ALONG 135W. WITH THE LEADING EDGE OF THE HIGHER CLOUDS WAS JUST 60 NM OFFSHORE THIS MORNING SO ANY SUN BREAKS OVER W WA ARE GOING TO HAVE TO HAPPEN BETWEEN NOW AND MIDDAY...SINCE THE OVERCAST HIGH CLOUDS WILL PROBABLY COVER W WA EARLY THIS AFTERNOON. MODELS AGREE THAT LIGHT RAIN WILL SPREAD OVER THE COAST LATE THIS AFTERNOON THEN SPREAD NE ACROSS ALL OF W WA BY 06Z/10 PM. THE WARM FRONT FROM THIS SYSTEM WILL BRING STRONG WARM ADVECTION WITH 40-60 KT S-SW WINDS ALOFT FROM 925MB-850MB TO W WA. THIS WILL PRODUCE HEAVY RAIN OVER THE OLYMPICS AND N CASCADES TONIGHT THROUGH THURSDAY NIGHT. THE WARM FRONT LOOKS LIKE IT GRADUALLY WEAKENS ON THURSDAY...BUT STRONG LOW LEVEL WINDS AHEAD OF THE OFFSHORE COLD FRONT WILL KEEP THE RAIN GOING THURSDAY NIGHT INTO EARLY FRIDAY MORNING. TOTAL PRECIP OVER THE AREA TONIGHT THROUGH FRIDAY MORNING WILL BE AROUND 3-6 INCHES OVER THE OLYMPICS AND N CASCADES WITH 0.50- 1.00 OVER THE INTERIOR LOWLANDS. SNOW LEVELS WILL RISE TO AROUND 7000 FEET BY MIDDAY THURSDAY. WEAK AND COOL EASTERLY FLOW THROUGH THE CASCADE PASSES SHOULD ALLOW A FEW INCHES OF LIGHT SNOW TO FALL INTO THURSDAY MORNING...BUT THE STRONG WARMING ALOFT WILL PROBABLY OVERWHELM THE COOL EAST LOW LEVEL FLOW FOR A CHANGE OVER TO RAIN BEFORE MIDDAY THURSDAY. THE COLD FRONT WILL FINALLY BE PUSHED INLAND FRIDAY MORNING ALLOWING THE RAIN TO TAPER OFF. A WEAK UPPER LEVEL RIDGE WILL MOVE OVER THE AREA FRIDAY AFTERNOON FOR GRADUAL DRYING. KAM .LONG TERM...PREVIOUS DISCUSSION FROM THE 236 AM AFD...AN UPPER TROUGH WILL BE CENTERED OVER THE NORTHERN CALIFORNIA OFFSHORE WATERS FRIDAY NIGHT AND LIFT NORTHEAST ACROSS THE PACIFIC NORTHWEST SATURDAY AND SATURDAY NIGHT. IT SHOULD BRING SOME SHOWERS TO THE FORECAST AREA BUT NOTHING SIGNIFICANT. THE SNOW LEVEL WILL BE 3000 TO 4000 FT. DRIER WEATHER IS LIKELY SUNDAY AND MONDAY AS AN UPPER RIDGE PROGRESSES SLOWLY ACROSS THE REGION. MODELS ARE IN FAIRLY GOOD AGREEMENT THAT ANOTHER FRONTAL SYSTEM WILL BRING THE NEXT ROUND OF STEADY WIDESPREAD PRECIPITATION MONDAY NIGHT AND TUESDAY...PROBABLY WITH SNOW LEVELS AGAIN CLIMBING TO AROUND 6000 FT. MCDONNAL && .AVIATION...WESTERLY FLOW ALOFT WILL TURN SOUTHWESTERLY LATE THIS AFTERNOON AS A FRONT APPROACHES THE COAST. SURFACE GRADIENTS WILL BECOME INCREASINGLY SOUTHEASTERLY. THE AIR MASS IS MOIST AND STABLE. IT WILL DRY SOMEWHAT THIS AFTERNOON THEN BECOME INCREASINGLY MOIST FROM THE WEST TONIGHT AS THE FRONT MOVES ONTO THE COAST. CONDITIONS ARE QUITE VARIABLE ACROSS THE AREA THIS MORNING WITH MAINLY MVFR CEILINGS AND SOME IFR CEILINGS IN THE INTERIOR VALLEYS. EXPECT THE LOWER LEVELS TO DRY OUT MIDDAY AS LOW LEVEL PRESSURE GRADIENTS BECOMING INCREASINGLY OFFSHORE. PRECIPITATION WILL MOVE IN FROM THE WEST THIS EVENING...BUT WITH EASTERLY PRES GRADIENTS CEILINGS AND VISIBILITY WILL START AS VFR THIS EVENING...THEN GRADUALLY DETERIORATE ON THE OLYMPIC PENINSULA OVERNIGHT WHILE STAYING MAINLY VFR IN THE INTERIOR. KSEA...SEVERAL CLOUD LAYERS BELOW 4K FT THIS MORNING INCLUDING ONE BELOW 1K FT. CONDITIONS WILL IMPROVE TO GOOD VFR AROUND 20Z. CEILINGS WILL GRADUALLY FALL TO OVC035 LATE TONIGHT WITH -RA. WINDS WILL BE SOUTH 4-8 KT THIS MORNING AND WILL TURN TO THE EAST OR NORTHEAST 4-7 KT AFTER ABOUT 20Z. CHB && .MARINE...A STRONG FRONT WILL MOVE INTO THE COASTAL WATERS THIS EVENING AND THEN SLOWLY MOVE INLAND TONIGHT AND THURSDAY. GALE WARNINGS ARE IN EFFECT FOR THE COAST AND THE CENTRAL AND EASTERN STRAIT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE REMAINING WATERS EXCEPT PUGET SOUND AND HOOD CANAL. SEAS WILL BUILD TONIGHT AND THURSDAY...BUT THE HIGHEST SEAS ON THE ORDER OF 17 TO 19 FEET FROM THE SOUTHWEST WILL REMAIN OVER THE OUTER WATERS AND WILL BE RELATIVELY SHORT PERIOD IN NATURE - REDUCING THE THREAT FOR SIGNIFICANT BEACH EROSION ON THE COASTLINE. A WEAKER SYSTEM WILL MOVE THROUGH THE WATERS FRIDAY OR FRIDAY NIGHT. A STRONGER SYSTEM WILL MOVE BY WELL TO THE SOUTH OF THE WATERS ON SATURDAY. CHB && .HYDROLOGY...ANOTHER 3 TO 6 INCHES OF PRECIPITATION WILL FALL OVER THE OLYMPICS TONIGHT THROUGH THURSDAY NIGHT...WITH THE SNOW LEVEL RISING TO 6500 TO 7500 FT. THIS WILL CAUSE THE SKOKOMISH RIVER -- WHICH ONLY FELL BELOW FLOOD STAGE TUESDAY MORNING -- TO FLOOD AGAIN. IT WILL PROBABLY BEGIN THURSDAY MORNING...AND THE ONLY REAL QUESTION IS WHETHER OR NOT IT WILL REACH ITS MAJOR FLOOD STAGE. THE FLOOD WATCH WILL BE UPDATED EARLY THIS MORNING. OTHER WESTERN WASHINGTON RIVERS FLOWING OFF THE OLYMPICS AND THE NORTH CASCADES WILL ALSO RISE SIGNIFICANTLY. HOWEVER NORTHWEST RIVER FORECAST CENTER GUIDANCE SHOWS MOST OF THESE RIVERS -- THE SATSOP... ELWHA...DUNGENESS...SKAGIT...AND STILLAGUAMISH -- CRESTING AT MOST WITH AROUND 70 PERCENT OF THE DISCHARGE NEEDED TO REACH FLOOD STAGE. SO THE THREAT ON THESE RIVERS LOOKS PRETTY LOW. THE GUIDANCE FOR THE NOOKSACK SHOWS IT GETTING CLOSEST TO FLOOD STAGE -- THE SOUTH FORK NOOKSACK SPECIFICALLY -- BUT STILL LESS THAN 80 PERCENT OF THE DISCHARGE CORRESPONDING TO FLOOD STAGE. AND IT IS WORTH NOTING THAT THE NOOKSACK DID NOT FLOOD DURING EITHER OF THE WESTERN WASHINGTON FLOODING EPISODES IN NOVEMBER AND DECEMBER. BOTTOM LINE IS I WILL UPDATE THE FLOOD POTENTIAL OUTLOOK TO STATE THAT FLOODING IS UNLIKELY ON RIVERS OTHER THAN THE SKOKOMISH. OTHERWISE...RIVER FLOODING IS NOT EXPECTED THE NEXT 7 DAYS. MCDONNAL && .SEW WATCHES/WARNINGS/ADVISORIES... WA...FLOOD WATCH FROM THIS EVENING THROUGH LATE FRIDAY NIGHT FOR HOOD CANAL AREA-LOWER CHEHALIS VALLEY AREA-OLYMPICS. PZ...SMALL CRAFT ADVISORY COAST UNTIL 4 PM PST THIS AFTERNOON. GALE WARNING COAST...CENTRAL AND E STRAIT FROM 4 PM THIS AFTERNOON TO 7 PM PST THURSDAY. SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 7 PM PST THURSDAY FOR GRAYS HARBOR BAR. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 7 PM PST THURSDAY FOR ADMIRALTY INLET-NORTHERN INLAND WATERS INCLUDING THE SAN JUAN ISLANDS. SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM PST THURSDAY FOR WEST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA. && $$ WWW.WEATHER.GOV/SEATTLE YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML