Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/30/14


AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1218 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA TOMORROW, THEN STALL TO OUR SOUTH AS A WEAK LOW PRESSURE SYSTEM RIDES ALONG IT MONDAY AND MONDAY NIGHT. IN THE WAKE OF THE FRONT, A COLD AIR MASS SLIDES SOUTH AND SETTLES IN OVER THE REGION THROUGH NEW YEARS DAY. ON FRIDAY, A LOW PRESSURE SYSTEM COULD DEVELOP OVER THE SOUTHERN PLAINS AND BEGIN LIFTING NORTHEAST TOWARDS THE REGION TO START THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... NO BIG CHANGES WITH THIS UPDATE EITHER, JUST SLIGHT POP ADJUSTMENTS BASED ON LATEST RAP AND HRRR BLEND. OVERALL, NO BIG CHANGES TO THE FORECAST TONIGHT. MOSTLY HOURLY GRID ADJUSTMENTS MADE, BUT WE DID MAKE SOME CHANGES TO THE OVERNIGHT LOWS FOR SOME AREAS. MAINLY PORTIONS OF THE PINE BARRENS AND NORTHERN NEW JERSEY WHERE TEMPERATURES HAVE ALREADY RADIATED QUITE EFFICIENTLY. OTHERWISE, FORECAST LOOKS ON TRACK. LIGHT SOUTHWESTERLY WINDS WILL CONTINUE TO USHER IN A SOMEWHAT MOISTER AIRMASS, AHEAD OF AN APPROACHING COLD FRONT. SKIES WILL CONTINUE TO THICKEN AND LOWER WITH TIME. THE POSITION OF THE FRONT LOOKS TO BE JUST TO OUR WEST RIGHT AROUND SUNRISE SUNDAY MORNING...THIS IS WHEN WE INCREASE POPS INTO THE LIKELY RANGE. THERMAL PROFILES SHOW ALL AN LIQUID PTYPE FOR THE REGION AS SURFACE TEMPERATURES WILL ONLY DROP INTO THE MID TO UPPER-30S IN A LOT OF PLACES EXCEPT WHERE THEY HAVE RADIATED MORE ALREADY. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... COLD FRONT WILL WORK ITS WAY THROUGH THE REGION FROM LATE MORNING THROUGH THE EVENING HOURS. HAVE INCREASE POPS TO CATEGORICAL FOR AT LEAST THE SOUTHERN HALF OF THE CWA BY SUNDAY AFTERNOON. SOME WEAK MID-LEVEL ENERGY SLIDES ALONG THE FRONT LATER TOMORROW AFTERNOON WHICH COULD ULTIMATELY SLOW ITS DEPARTURE DOWN A BIT. A MAJORITY OF THE GUIDANCE HAS US DRYING OUT FROM NORTHWEST TO SOUTHEAST BY LATE SUNDAY EVENING, JUST AHEAD OF THE BETTER LOW-LEVEL CAA KICKING IN. THERE COULD BE SOME RAIN/SNOW MIX ACROSS OUR NORTHWEST ZONES LATE IN THE PERIOD, DEPENDING ON HOW FAST WE CAN COOL BELOW 850MB AND HOW MUCH MOISTURE REMAINS. TEMPERATURES WILL BE ABOVE NORMAL ONCE AGAIN THOUGH SEVERAL DEGREES COOLER THAN TODAY WITH THE AMOUNT OF CLOUD COVER EXPECTED AND THE RAIN SHOWERS MOVING IN. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... STILL A VERY LOW CONFIDENCE FORECAST IN THE WAKE OF THE COLD FRONT FROM SUNDAY NIGHT THROUGH TUESDAY. MOST MODELS DID AGREE ON ONE THING, THEY ARE MOSTLY FOR LOCATIONS GENERALLY ALONG AND NORTH OF A PHILLY TO ACY LINE. NAM IS BY FAR THE WETTEST AND SNOWIEST OUTLIER SHOWING SNOW FOR NEARLY ALL OF THE REGION. GIVEN THAT THE TREND WITH THE OTHER MODELS HAS BEEN DRIER FOR A FEW RUNS NOW, AND GIVEN HOW MUCH OF AN OUTLIER THE NAM IS, FORECAST FAVORS THE GFS AND ECMWF. THEY BOTH SHOW THE FRONT PUSHING FURTHER SOUTH BEFORE STALLING, WITH THE FRONT NOW EXPECTED TO STALL OR SLOW BY LATE MONDAY AFTERNOON GENERALLY FROM THE FL PANHANDLE TO THE SC COAST. AS A RESULT, BUT THE TIME THE SECONDARY LOW DEEPENS AND LIFTS NE ALONG THE FRONT, IT IS MUCH FURTHER OUT TO SEA THAN WHAT PREVIOUS RUNS SHOWED. EVEN IN DELMARVA THOUGH, THIS DOESN/T APPEAR TO BE A MAJOR EVENT AS WHEN THE MOISTURE IS THE MOST ABUNDANT, SUNDAY NIGHT, IT WILL STILL BE WARM ENOUGH TO SUPPORT RAIN. BY MONDAY AFTERNOON INTO MONDAY NIGHT, COLDER AIR HAS SETTLED IN, BUT SO HAS DRY AIR ADVECTION, LIMITING MOISTURE AVAILABILITY. SO DO NOT EXPECT ANY ACCUMULATIONS ABOVE AN INCH. FOR MUCH OF THE REST OF THE WEEK, THE WEATHER LOOKS TRANQUIL, ALBEIT COLD. THE CONTINENTAL POLAR AIR MASS CONTINUES TO SETTLE IN OVER THE REGION. AS SUCH MANY LOCATIONS NORTHWEST OF THE FALL LINE WILL STRUGGLE TO GET ABOVE FREEZING FROM TUESDAY THROUGH FRIDAY. THE NEXT THING ON THE HORIZON IS AN INTENSE LOW, MODELED TO BE OVER THE SOUTHERN PLAINS BY FRIDAY LIFTING TOWARDS THE GREAT LAKES REGION. GIVEN HOW MUCH UNCERTAINTY THERE IS EARLY IN THE WEEK, AND GIVEN A LARGE SPREAD IN TIMING AND TRACK BETWEEN THE GFS AND ECMWF, IT/S RISKY TO HANG A HAT ON EITHER SOLUTION. HOWEVER, IT DOES APPEAR THAT THE IMPACTS TO THIS REGION WILL BE A CHANCE FOR PRECIPITATION, PRIMARILY WITHIN THE WARM SECTOR OF THIS LOW AS IT STAYS NW OF THE REGION (MEANING PRIMARILY RAIN). WILL HAVE A CHANCE TO REFINE THIS ONCE WE SEE HOW THE EARLY WEEK SYSTEM PLAYS OUT. && .AVIATION /05Z SUNDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 06Z TAFS CONTAIN MVFR CONDITIONS MAINLY DURING MORE FREQUENT SHOWERS DURING THE DAYTIME HOURS. EARLY MORNING, VFR SHOWERS MOVING INTO NORTHERN TERMINALS TOWARD DAWN. SOME MVFR FOG AT KILG, SHOULD DISSIPATE AS CLOUDS BECOME THICKER. OTHERWISE A VFR CIG WITH LIGHT WINDS. THIS MORNING AND AFTERNOON...NORTHERN AIRPORTS AND TERMINALS VFR SHOWERS SHOULD BE ONGOING TERMINALS WITH CIGS LOWERING TO MVFR LATER IN THE MORNING. VFR CIG IMPROVEMENT DURING THE AFTERNOON. KPHL AREA AIRPORTS AND TERMINALS/AIRPORTS TO THE SOUTH/SOUTHEAST EXPECTING A VFR CIG MORNING WITH SHOWERS OCCURRING MAINLY DURING THE AFTERNOON. MVFR CIGS ARE POSSIBLE DURING THE AFTERNOON. ALL TERMINALS VSBY RESTRICTIONS TOO BRIEF TO INCLUDE, MAINLY VFR VSBYS. WINDS WILL BECOME WEST TO NORTHWEST DURING THE LATE MORNING TO EARLY AFTERNOON AS THE COLD FRONT MOVES THROUGH. SPEEDS SHOULD BE LESS THAN 10 KNOTS. THIS EVENING. VFR MID LEVEL CIGS. NORTHWEST WINDS AVERAGING 5 TO 10 KNOTS. SOUTHERN TERMINALS AND DELMARVA AIRPORTS MIGHT SEE A SECOND SURGE OF MAINLY VFR RAIN LATE AT EVENING AND OVERNIGHT. OUTLOOK... MONDAY TO TUESDAY....MOSTLY VFR CONDITIONS EXPECTED ALONG AND NORTH OF A KACY TO KPHL LINE. FOR KMIV AND KILG, THERE IS A CHANCE FOR PRECIPITATION, SOME OF WHICH COULD FALL AS SNOW. MVFR CONDITIONS ARE POSSIBLE WITH ANY PRECIP. TUESDAY NIGHT THROUGH THURSDAY...MOSTLY VFR CONDITIONS EXPECTED ACROSS THE REGION. && .MARINE... TONIGHT - SUNDAY...SUB-SCA CONDITIONS EXPECTED. SEAS WILL CONTINUE AROUND 3 FEET THROUGH LATE THIS EVENING BEFORE AN INCREASE TO AROUND 4 FEET IS POSSIBLE...BETTER FARTHER NORTH. WINDS WILL REMAIN RELATIVELY LIGHT OUT OF THE SOUTH-SOUTHWEST AROUND 10 TO MAYBE 15 KNOTS, THOUGH GUSTS SHOULD BE KEPT BELOW 20 KNOTS. WINDS BACK TOWARDS THE WEST LATER TOMORROW EVENING AS A SURFACE COLD FRONT MOVES THROUGH. OUTLOOK... MONDAY THROUGH TUESDAY...CONDITIONS SHOULD STAY BELOW SCA THRESHOLDS. HOWEVER, WAVES OF 3 TO 4 FT, AND WIND GUSTS NEAR OR JUST ABOVE 20KT WILL BE POSSIBLE ESPECIALLY LATE MONDAY NIGHT INTO TUESDAY. TUESDAY NIGHT THROUGH THURSDAY...SUB SMALL CRAFT ADVISORY CONDITIONS EXPECTED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...JOHNSON NEAR TERM...GIGI/HEAVENER/ROBERTSON SHORT TERM...HEAVENER LONG TERM...JOHNSON AVIATION...GIGI/JOHNSON MARINE...HEAVENER/JOHNSON
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
200 PM EST SUN DEC 28 2014 .SYNOPSIS... 19Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE FLORIDA PENINSULA UNDER THE PROTECTIVE COVER OF A LARGE MID/UPPER LEVEL RIDGE CENTERED NEAR THE BAHAMAS. OUR DEEP LAYER FLOW ALOFT IS FROM THE SOUTH AND SOUTHWEST BETWEEN THIS FEATURE AND A POTENT TROUGH/SHORTWAVE FEATURE EJECTING QUICKLY EASTWARD ACROSS THE SOUTHERN PLAINS/NORTHERN MEXICO. FINALLY FURTHER UPSTREAM WE SEE A SIGNIFICANT PIECE OF ENERGY/JET STREAK DIVING DOWN OVER THE PACIFIC COAST. THROUGH THE EARLY PORTION OF THE WEEK...OUT WEATHER WILL BE DETERMINED BY THE INTERACTION BETWEEN THE RIDGE TO OUR SOUTH AND EAST...AND THE APPROACHING SHORTWAVE FROM THE WEST. AT THE SURFACE...ATLANTIC HIGH PRESSURE RIDGES BACK WEST INTO THE FLORIDA PENINSULA AND EASTERN GULF...AND SHOULD HOLD IN PLACE THROUGH MONDAY. TEMPERATURES HAVE WARMED INTO THE4 LOWER 80S INLAND AND GENERALLY IN THE 70S AT THE COAST. ONLY EXCEPTION IS ALONG THE IMMEDIATE COAST OVER THE FAR NORTHERN ZONES WHERE THE ONSHORE FLOW IS OFF OF QUITE COOL SHELF WATERS. THE OBSERVATION AT CEDAR KEY IS ONLY IN THE MIDDLE 60S. THESE TEMPS IN THE 60S ARE LIKELY CONFINED TO ONLY A MILE OR TWO FROM THE WATER WITH TEMPERATURES RAPIDLY WARMING WITH INLAND EXTENT. && .SHORT TERM (REST OF TODAY THROUGH MONDAY)... REST OF TODAY... THE STRONG TERRESTRIAL HEATING AND GENERALLY WEAK GRADIENT HAVE ALLOWED A FEEBLE SEA-BREEZE TO DEVELOP ALONG THE COAST THIS AFTERNOON. THIS SEA-BREEZE WILL KEEP THE BEACHES A BIT COOLER COMPARED WITH INLAND LOCATIONS AS THE FLOW IS OFF THE RELATIVELY COOLER SHELF WATERS. THE FORECAST THE REST OF THE DAY IS FOR RAIN FREE CONDITIONS DUE TO THE GENERALLY DRY COLUMN ALOFT AND NO SYNOPTIC SUPPORT FOR LIFT IN THE VICINITY. THERE IS A COLD FRONT STRETCHED ACROSS THE SOUTHEAST PORTION OF THE COUNTY THAT IS BRINGING SHOWERS INTO THE FLORIDA PANHANDLE/AL/GA...HOWEVER THE STRONG UPPER RIDGE WILL NOT ALLOW THIS FEATURE TO MOVE VERY FAR THROUGH TONIGHT AND IT WILL NOT BE A CONCERN FOR OUR FORECAST TILL AT LEAST TUESDAY. TONIGHT... FAIR AND DRY CONDITIONS CONTINUE. SHORTWAVE ENERGY WILL BE RAPIDLY APPROACHING THE SOUTHEAST CONUS. HOWEVER...AS IT APPROACHES...THIS ENERGY WILL BE QUICKLY SHEARING OUT AND DEAMPLIFYING. ABOUT THE ONLY EFFECT THIS FEATURE WILL HAVE ON OUR LOCAL WEATHER THROUGH TONIGHT WILL BE TO BREAK DOWN/DEAMPLIFY THE UPPER RIDGE AND BEGIN TO TURN OUR SYNOPTIC FLOW ALOFT MORE ZONAL IN NATURE. THE SURFACE FRONT WILL GET A LITTLE "KICK" EASTWARD WITH THE PASSING ENERGY...BUT SHOULD BE STALLED NEAR APALACHEE BAY BY MONDAY MORNING. WE DO ANTICIPATE SOME ADDITIONAL FOG/VISIBILITY ISSUES TONIGHT INTO EARLY MONDAY MORNING...HOWEVER WITH THE RIDGE BREAKING DOWN OVERNIGHT...THE SYNOPTIC SETUP FOR WIDESPREAD DENSE FOG DOES NOT LOOK AS FAVORABLE. WILL GO WITH AREAS OF FOG...SOME OF WHICH SHOULD BECOME LOCALLY DENSE. UNFORTUNATELY...MANY OF OUR AIRPORTS ARE IN LOWER/MORE FOG PRONE LOCATIONS AND WILL PROB BE IMPACTED BY ANOTHER ROUND OF FLIGHT RESTRICTIONS EARLY MONDAY. MONDAY... MORE OF THE SAME. AREAS OF FOG WILL SLOWLY BURN OFF BETWEEN 13-15Z. THE UPPER RIDGE WILL BE DEAMPLIFIED...HOWEVER THE LOWER COLUMN WILL STILL BE VERY WARM AND SUFFICIENT TO KEEP OUR TEMPS WELL ABOVE AVERAGE. WOULD EXPECT LOWER 80S FOR HIGHS SOUTH OF THE I-4 CORRIDOR AND AWAY FROM THE IMMEDIATE COAST. COULD CERTAINLY SEE LOWER 80S FURTHER NORTH...HOWEVER ANTICIPATING A BIT MORE IN THE WAY OF CLOUDS FOR CENTRAL AND NORTHERN PORTIONS OF THE STATE AND HENCE TEMPS MAY BE HELD DOWN IN THE MID/UPPER 70S. THE FRONT LOOKS TO REMAIN QUASI-STATIONARY UP ACROSS APALACHEE BAY SINCE THERE WILL STILL BE LITTLE IN THE WAY OF ATMOSPHERIC PUSH. THE PROXIMITY OF THE FOCUS ALONG THE BOUNDARY MAY BE ENOUGH TO SUPPORT A FEW SHOWERS UP TO LEVY COUNTY...BUT OTHERWISE CONDITIONS ARE EXPECTED TO REMAIN DRY. THE ONLY OTHER LOCATION THAT RUNS THE RISK OF A BRIEF AFTERNOON SHOWER LOOKS TO BE AROUND HIGHLANDS COUNTY WHERE A FEW OF THE HIRES EXPLICIT CONVECTION GUIDANCE MEMBERS ARE FOCUSING A FEW CONVECTIVE CELLS AFTER 18Z ASSOCIATED WITH A SEA-BREEZE MERGER. GIVEN THE COLUMN CHARACTERISTICS FOR TOMORROW...CAN NOT RULE OUT THE SUPPORT FOR A BRIEF CONVECTIVE UPDRAFT AND WILL ADD A 20% POP FOR A SHOWER OVER THE INLAND SOUTH-CENTRAL ZONES...EVEN THOUGH MOST SPOTS WILL NOT SEE ANYTHING. EVEN UP TOWARD LEVY COUNTY WE DO NOT EXPECT ENOUGH RAIN TO SERIOUSLY HAMPER ANY OUTDOOR EVENTS/ACTIVITIES. BEST RAIN CHANCES ON MONDAY WILL STAY OFF TO THE NORTH AND NORTHWEST OF OUR ZONES. THE WEAK PASSING IMPULSE THAT FINALLY "SHOVES" THE FRONT DOWN INTO THE FL PENINSULA IS ON TUESDAY...AND IT WILL BE AT THAT TIME THAT LOW SHOWER CHANCES RETURN TO THE FORECAST FOR MOST OF US. HAVE A GREAT SECOND HALF OF YOUR WEEKEND. GET OUTSIDE AND ENJOY THE WARM LATE DECEMBER WEATHER! && LONG TERM (TUESDAY THROUGH NEXT SUNDAY)... THE PERIOD BEGINS ALOFT WITH A SHORT WAVE TROUGH ROUGHLY WEST TO EAST ACROSS THE NORTHERN U.S. ROCKIES WHILE A ROBUST ATLANTIC SUBTROPICAL RIDGE REACHED IN ACROSS THE SOUTHERN GULF OF MEXICO AND THE NORTHWESTERN CARIBBEAN SEA. AT THE SURFACE HIGH PRESSURE SPRAWLED ACROSS THE CANADIAN PRAIRIES AND THE NORTHERN AND CENTRAL U.S. PLAINS WITH A LOW PRESSURE CENTER OFF THE MID-ATLANTIC COAST THAT TRAILED A WEAK COLD FRONT BACK ACROSS SOUTH GA/NORTH FL INTO THE GULF OF MEXICO. WITH TIME THE SHORT WAVE TROUGH DROPS SOUTH ALONG THE SIERRA NEVADA RANGE THEN DEEPENS INTO A CLOSED LOW AS IT TRACKS ACROSS THE GREAT BASIN TO THE CENTRAL HIGH PLAINS. THE GULF AND CARIBBEAN RIDGE BUILDS NORTHWARD OVER THE EASTERN STATES. MEANWHILE THE FRONT SETTLES SOUTHWARD ACROSS THE REST OF FL AS IT SLOWLY DISSIPATES BY WED AS THE SURFACE HIGH RELOCATES TO THE CENTRAL U.S. PLAINS AND BUILDS OVER MUCH OF THE EASTERN CONUS. DURING THE WEEKEND THE UPPER LOW OPENS INTO A TROUGH THAT TRACKS NORTHEAST ACROSS THE GREAT LAKES INTO SOUTHEAST CANADA...ALONG WITH A SURFACE REFLECTION TRAILING A COLD FRONT THAT GETS STRUNG OUT ALONG THE EASTERN SEABOARD INTO THE CENTRAL GULF OF MEXICO. THE RIDGING...BOTH ALOFT AND SURFACE...PIVOTS OUT OVER THE ATLANTIC AS IT HANGS ON OVER MUCH OF BOTH FL AND THE GULF. WHILE THE REST OF THE NATION WILL HAVE AN ACTIVE PATTERN THERE WILL BE LIMITED IMPACT ACROSS WEST CENTRAL AND SOUTHWEST FL. THE FIRST FRONT COMES THROUGH WITH ONLY SLIGHT CHANCE TO CHANCE SHOWERS MAINLY TUE. THEN DRY CONDITIONS GENERALLY PREVAIL AS THE SECOND FRONT STAYS TO THE NORTH THROUGH THE WEEKEND. HOWEVER...THE FRONT WILL BE CLOSE ENOUGH FOR SOME ENERGY TO COMBINE WITH INCREASING MOISTURE ON SOUTHERLY FLOW TO SUPPORT LOW CHANCE SHOWERS ACROSS THE NORTH SAT AND SUN. TEMPERATURES INITIALLY ABOVE NORMAL COOL DOWN SLIGHTLY MID-WEEK...AFTER THE FRONT MOVES THROUGH AND HIGH PRESSURE BUILDS IN TO THE NORTHWEST AND NORTH. FOR THE END OF WEEK AND THE WEEKEND TEMPERATURES REMAIN ABOVE NORMAL AND SLOWLY WARM AS THE HIGH MOVES BY TO THE NORTH THEN NORTHEAST WITH LOW LEVEL EVENTUALLY VEERING TO SOUTHERLY. && AVIATION... VFR CONDITIONS ARE GENERALLY PREVAILING ACROSS THE REGION THIS AFTERNOON AND EXPECT THAT TREND TO CONTINUE THROUGH THE EVENING. WINDS ARE LIGHT SOUTHERLY INLAND AND HAVE BECOME ONSHORE NEAR THE COAST. WINDS WILL DISSIPATE AND BECOME LIGHT VARIABLE SHORTLY AFTER SUNSET. AREAS OF FOG ARE EXPECTED TO ONCE AGAIN DEVELOP AFTER MIDNIGHT AND LINGER THROUGH MID-MORNING MONDAY. ALTHOUGH NOT EXPECTED TO BE AS WIDESPREAD AS SATURDAY NIGHT...THE POTENTIAL FOR SEVERAL HOURS AT IFR OR LOWER DOES EXIST. MOST LIKELY SPOTS TO SEE THE SIGNIFICANT RESTRICTIONS WILL BE KLAL...KPGD...KRSW AND KFMY. ONCE THE FOG LIFTS BY 14-15Z MONDAY...VFR CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE DAY. && MARINE... LIGHT SOUTH SOUTHEAST WINDS ON THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL CONTINUE FOR THE NEXT COUPLE OF DAYS OVER THE COASTAL WATERS. SEA FOG WILL BE POSSIBLE TODAY AND MONDAY WITH A WARM AND HUMID AIR MASS OVERRIDING THE RELATIVELY COOLER WATERS. A WEAK FRONTAL BOUNDARY APPROACHES THE AREA ON MONDAY AND TUESDAY KEEPING THE SOUTHERLY WIND FLOW IN PLACE AND PRODUCING A SLIGHT CHANCE OF SHOWERS. THE WINDS WILL SHIFT TO THE NORTH NORTHEAST IN THE WAKE OF THIS FRONT ON TUESDAY...AND WILL REMAIN OUT OF THE NORTHEAST THROUGH THE WEEK AS HIGH PRESSURE SETTLES INTO THE REGION. && .FIRE WEATHER... NO SIGNIFICANT FIRE WEATHER CONCERNS FOR THE NEXT COUPLE OF DAYS OTHER THAN AREAS OF DENSE FOG EXPECTED LATER TONIGHT INTO MONDAY MORNING. RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL LEVELS THROUGH TUESDAY WITH JUST A FEW SHOWERS AROUND ON TUESDAY. FOG POTENTIAL...ALTHOUGH NOT EXPECTED TO BE AS WIDESPREAD AS SATURDAY NIGHT...AREAS OF FOG ARE EXPECTED TO DEVELOP OVERNIGHT INTO EARLY TUESDAY MORNING AND SOME OF THE FOG IS LIKELY TO BECOME DENSE. DENSE FOG ADVISORIES MAY BECOME REQUIRED FOR SOME AREAS AFTER MIDNIGHT. && .PRELIMINARY POINT TEMPS/POPS... TPA 65 77 66 77 / 0 10 10 20 FMY 66 80 66 81 / 0 10 20 10 GIF 64 80 64 78 / 0 10 10 20 SRQ 64 77 65 76 / 0 10 10 10 BKV 60 79 63 77 / 0 10 20 20 SPG 66 76 66 76 / 0 10 20 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/AVIATION/FIRE WX...MROCZKA MARINE...WYNN LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1045 AM EST SUN DEC 28 2014 UPDATE (REST OF TODAY THROUGH MONDAY)... 15Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE FLORIDA PENINSULA UNDER THE PROTECTIVE COVER OF A LARGE MID/UPPER LEVEL RIDGE CENTERED NEAR THE BAHAMAS. OUR DEEP LAYER FLOW ALOFT IS FROM THE SOUTH AND SOUTHWEST BETWEEN THIS FEATURE AND A POTENT TROUGH/SHORTWAVE FEATURE EJECTING QUICKLY EASTWARD ACROSS THE SOUTHERN PLAINS/NORTHERN MEXICO. FINALLY FURTHER UPSTREAM WE SEE A SIGNIFICANT PIECE OF ENERGY/JET STREAK DIVING DOWN OVER THE PACIFIC COAST. THROUGH THE EARLY PORTION OF THE WEEK...OUT WEATHER WILL BE DETERMINED BY THE INTERACTION BETWEEN THE RIDGE TO OUR SOUTH AND EAST...AND THE APPROACHING SHORTWAVE FROM THE WEST. AT THE SURFACE...ATLANTIC HIGH PRESSURE RIDGES BACK WEST INTO THE FLORIDA PENINSULA AND EASTERN GULF...AND SHOULD HOLD IN PLACE THROUGH MONDAY. THE COMBINATION OF THE UPPER RIDGE PRESSING DOWN FROM ABOVE AND ABUNDANT LOW LEVEL MOISTURE MADE FOR WIDESPREAD DENSE FOG AROUND THE AREA THIS MORNING. THE LATE DECEMBER SUN IS NOT THE STRONGEST OF THE YEAR...BUT HAS BEEN DOING THE JOB OF BURNING OFF THE THIN LAYER OF SURFACE FOG THE PAST FEW HOURS...AND THE DENSE FOG ADVISORY HAS BEEN ALLOWED TO EXPIRE. THE STABLE AND FOGGY NEAR SURFACE LAYER WAS WELL SAMPLED IN THE 28/12Z KTBW SOUNDING PROFILE...BUT ABOVE THIS LAYER WE SEE A GENERALLY DRY ATMOSPHERE RELATED TO THE SUBSIDENCE INVERSION LOCATED JUST ABOVE 900MB. REST OF TODAY... NOW THAT THE FOG HAS BURNED OFF WE CAN EXPECT A GOOD DEAL OF SUNSHINE THE REST OF THE DAY...ALTHOUGH THE LOWER LEVEL MOISTURE AND RISING THERMALS SHOULD ALLOW FOR A SCATTERED CUMULUS FIELD TO BECOME ESTABLISHED DURING THE AFTERNOON. THE LOWER LEVELS OF THE ATMOSPHERE ARE VERY WARM FOR LATE DECEMBER. THE 850MB TEMPERATURE OFF THE MORNING SOUNDING WAS 17C. WITH THIS PROFILE...EVEN A MODEST AMOUNT OF DIURNAL MIXING IS GOING TO MIX OUT OUR HIGH TEMPERATURES WELL INTO THE 70S...AND LIKELY INTO THE 80S FOR MANY SPOTS AWAY FROM THE IMMEDIATE COAST. THE STRONG TERRESTRIAL HEATING AND GENERALLY WEAK GRADIENT SHOULD ALSO ALLOW A FEEBLE SEA-BREEZE TO DEVELOP ALONG THE COAST THIS AFTERNOON. THIS SEA-BREEZE WILL KEEP THE BEACHES A BIT COOLER COMPARED WITH INLAND LOCATIONS AS THE FLOW TURNS FROM OFF THE RELATIVELY COOLER SHELF WATERS. THE FORECAST THE REST OF THE DAY IS FOR RAIN FREE CONDITIONS DUE TO THE GENERALLY DRY COLUMN ALOFT AND NO SYNOPTIC SUPPORT FOR LIFT IN THE VICINITY. THERE IS A COLD FRONT STRETCHED ACROSS THE SOUTHEAST PORTION OF THE COUNTY THAT WILL BRING SHOWERS INTO THE FLORIDA PANHANDLE/AL/GA TODAY...HOWEVER THE STRONG UPPER RIDGE WILL NOT ALLOW THIS FEATURE TO MOVE VERY FAR THROUGH TONIGHT AND IT WILL NOT BE A CONCERN FOR OUR FORECAST TILL AT LEAST TUESDAY. TONIGHT... FAIR AND DRY CONDITIONS CONTINUE. SHORTWAVE ENERGY WILL BE RAPIDLY APPROACHING THE SOUTHEAST CONUS. HOWEVER...AS IT APPROACHES...THIS ENERGY WILL BE QUICKLY SHEARING OUT AND DEAMPLIFYING. ABOUT THE ONLY EFFECT THIS FEATURE WILL HAVE ON OUR LOCAL WEATHER THROUGH TONIGHT WILL BE TO BREAK DOWN/DEAMPLIFY THE UPPER RIDGE AND BEGIN TO TURN OUR SYNOPTIC FLOW ALOFT MORE ZONAL IN NATURE. THE SURFACE FRONT WILL GET A LITTLE "KICK" EASTWARD WITH THE PASSING ENERGY...BUT SHOULD BE STALLED NEAR APALACHEE BAY BY MONDAY MORNING. WE DO ANTICIPATE SOME ADDITIONAL FOG/VISIBILITY ISSUES TONIGHT INTO EARLY MONDAY MORNING...HOWEVER WITH THE RIDGE BREAKING DOWN OVERNIGHT...THE SYNOPTIC SETUP FOR WIDESPREAD DENSE FOG DOES NOT LOOK AS FAVORABLE. WILL GO WITH AREAS OF FOG...SOME OF WHICH SHOULD BECOME LOCALLY DENSE. UNFORTUNATELY...MANY OF OUR AIRPORTS ARE IN LOWER/MORE FOG PRONE LOCATIONS AND WILL PROB BE IMPACTED BY ANOTHER ROUND OF FLIGHT RESTRICTIONS EARLY MONDAY. MONDAY... MORE OF THE SAME. AREAS OF FOG WILL SLOWLY BURN OFF BETWEEN 13-15Z. THE UPPER RIDGE WILL BE DEAMPLIFIED...HOWEVER THE LOWER COLUMN WILL STILL BE VERY WARM AND SUFFICIENT TO KEEP OUR TEMPS WELL ABOVE AVERAGE. WOULD EXPECT LOWER 80S FOR HIGHS SOUTH OF THE I-4 CORRIDOR AND AWAY FROM THE IMMEDIATE COAST. COULD CERTAINLY SEE LOWER 80S FURTHER NORTH...HOWEVER ANTICIPATING A BIT MORE IN THE WAY OF CLOUDS FOR CENTRAL AND NORTHERN PORTIONS OF THE STATE AND HENCE TEMPS MAY BE HELD DOWN IN THE MID/UPPER 70S. THE FRONT LOOKS TO REMAIN QUASI-STATIONARY UP ACROSS APALACHEE BAY SINCE THERE WILL STILL BE LITTLE IN THE WAY OF ATMOSPHERIC PUSH. THE PROXIMITY OF THE FOCUS ALONG THE BOUNDARY MAY BE ENOUGH TO SUPPORT A FEW SHOWERS UP TO LEVY COUNTY...BUT OTHERWISE CONDITIONS SHOULD BE DRY. EVEN UP TOWARD LEVY COUNTY WE DO NOT EXPECT ENOUGH RAIN TO SERIOUSLY HAMPER ANY OUTDOOR EVENTS/ACTIVITIES. BEST RAIN CHANCES ON MONDAY WILL STAY OFF TO THE NORTH AND NORTHWEST OF OUR ZONES. THE WEAK PASSING IMPULSE THAT FINALLY "SHOVES" THE FRONT DOWN INTO THE FL PENINSULA IS ON TUESDAY...AND IT WILL BE AT THAT TIME THAT SHOWER CHANCES RETURN TO THE FORECAST FOR MOST OF US. HAVE A GREAT SECOND HALF OF YOUR WEEKEND. GET OUTSIDE AND ENJOY THE WARM LATE DECEMBER WEATHER! && LONG TERM (MONDAY NIGHT-FRIDAY)... INTERESTING U/L PATTERN EVOLUTION ACROSS NORTH AMERICA THROUGH THE LONG RANGE PERIOD...BUT WITH LITTLE IMPACT OVER WEST CENTRAL AND SOUTHWEST FLORIDA AS A STRONG SUBTROPICAL RIDGE ANCHORED ACROSS THE CARIBBEAN WILL KEEP THE MAIN WESTERLIES NORTH OF THE REGION. A STRONG U/L RIDGE OVER THE EASTERN PACIFIC WILL EXTEND NORTH THROUGH ALASKA ON TUESDAY. DOWNSTREAM...A POSITIVELY TILTED L/W TROUGH WILL EXTEND FROM HUDSON BAY TO THE DESERT SOUTHWEST...WITH QUASI-ZONAL FLOW ACROSS THE SOUTHERN TIER OF THE U.S. TUESDAY AND WEDNESDAY...A STRONG U/L DISTURBANCE WILL DIG DOWN THE BACKSIDE OF THE EAST PACIFIC RIDGE WITH AN U/L LOW CUTTING OFF OVER THE SOUTHWEST U.S. ESTABLISHING A STRONG OMEGA BLOCK OVER THE EASTERN PACIFIC. SOUTHERN STREAM FLOW WILL UNDER CUT THE EAST PACIFIC BLOCK WITH PRIMARY NORTHERN STREAM FLOW INTO THE CONUS DOWN THE BACKSIDE OF THE RIDGE FROM WESTERN CANADA AND ACROSS THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES REGION. AT THE SURFACE...A COLD FRONT WILL PUSH SLOWLY ACROSS THE FORECAST AREA TUESDAY WITH A SLIGHT CHANCE OF A SHOWER. THE FRONT WILL STALL OVER SOUTH FLORIDA WEDNESDAY AS THE FRONT BECOMES PARALLEL TO THE U/L FLOW. SURFACE HIGH PRESSURE WILL BUILD OVER WEST CENTRAL AND SOUTHWEST FLORIDA BEHIND THE FRONT WITH SLIGHTLY COOLER TEMPERATURES ADVECTING ACROSS THE REGION THROUGH THURSDAY. ON FRIDAY...THE U/L LOW OVER THE DESERT SOUTHWEST WILL BEGIN TO OPEN UP AND EJECT EAST APPROACHING THE SOUTHERN PLAINS LATE IN THE DAY. SURFACE HIGH PRESSURE WILL MOVE OFF THE MID ATLANTIC COAST WITH LONG FETCH EAST TO SOUTHEAST BOUNDARY LAYER RETURN FLOW DEVELOPING ACROSS THE FLORIDA PENINSULA WITH A SIGNIFICANT INCREASE IN BOUNDARY LAYER MOISTURE AND WARMER TEMPERATURES. PREDOMINATELY DRY CONDITIONS ARE EXPECTED THROUGH THE EXTENDED PERIOD WITH TEMPERATURES RUNNING ABOVE CLIMATIC NORMALS. && AVIATION... CONDITIONS ARE RETURNED TO VFR AT ALL TERMINALS AFTER THE WIDESPREAD DENSE FOG EARLIER IN THE MORNING. THE REMAINDER OF THE DAY SHOULD FEATURE THE VFR CONDITIONS UNDER A DEVELOPING SCT CU FIELDS. LIGHT SE/S WINDS WILL SHIFT SW/W DURING THE MIDDLE AND LATER AFTERNOON HOURS NEAR THE COAST WITH A WEAK SEABREEZE DEVELOPING. AREAS OF FOG WILL AGAIN DEVELOP AFTER MIDNIGHT TONIGHT...HOWEVER CONDITIONS DO NOT APPEAR AS FAVORABLE TO SEE THE EXTENT OF DENSE FOG SEEN THIS PAST OVERNIGHT. BEST CHANCES TO SEE SIGNIFICANT VIS/CIG RESTRICTION LOOK TO BE KLAL AND KPGD. && MARINE... LIGHT SOUTH SOUTHEAST WINDS ON THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL CONTINUE FOR THE NEXT COUPLE OF DAYS OVER THE COASTAL WATERS. SEA FOG WILL BE POSSIBLE TODAY AND MONDAY WITH A WARM AND HUMID AIR MASS OVERRIDING THE RELATIVELY COOLER WATERS. A WEAK FRONTAL BOUNDARY APPROACHES THE AREA ON MONDAY AND TUESDAY KEEPING THE SOUTHERLY WIND FLOW IN PLACE AND PRODUCING A SLIGHT CHANCE OF SHOWERS. THE WINDS WILL SHIFT TO THE NORTH NORTHEAST IN THE WAKE OF THIS FRONT ON TUESDAY...AND WILL REMAIN OUT OF THE NORTHEAST THROUGH THE WEEK AS HIGH PRESSURE SETTLES INTO THE REGION. && .PRELIMINARY POINT TEMPS/POPS... TPA 79 65 78 65 / 0 10 10 30 FMY 81 66 81 66 / 0 0 10 10 GIF 82 64 81 64 / 0 0 10 20 SRQ 77 64 77 65 / 0 0 10 30 BKV 81 60 79 61 / 0 0 10 30 SPG 77 66 76 65 / 0 10 10 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/AVIATION...MROCZKA MARINE...WYNN LONG TERM...OGLESBY
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
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
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
652 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT TO OUR WEST WILL SLOWLY MAKE ITS WAY ACROSS THE AREA TONIGHT AND MONDAY BRINGING THE CHANCE FOR RAIN. DRY WEATHER AND COOLER TEMPERATURES WILL RETURN FOR MID-WEEK AS HIGH PRESSURE DOMINATES. ANOTHER COLD FRONT WILL BRING THE THREAT OF RAIN NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... THE UPPER LEVEL FLOW WILL REMAIN HIGHLY AMPLIFIED WITH A RIDGE CENTERED OVER THE BAHAMAS AND CUBA...AND A POSITIVELY TILTED TROUGH EXTENDING FROM THE WESTERN GREAT LAKES REGION INTO WEST TEXAS. AT THE SURFACE...HIGH PRESSURE WAS OVER THE WESTERN ATLANTIC WITH A COLD FRONT EXTENDING FROM THE CENTRAL APPALACHIANS SOUTHWESTWARD TO MISSISSIPPI. DEEP SOUTHWEST FLOW AHEAD OF THE FRONT WILL PUMP MOISTURE INTO OUR AREA TODAY AND TONIGHT. MODELS KEEP MUCH OF THE RAINFALL ACROSS NORTHERN GEORGIA INTO NORTHERN SOUTH CAROLINA TODAY. WE KEPT THE HIGHEST POPS ACROSS THE NORTH AND WEST...AND DRIER FARTHER SOUTH AND EAST. MUCH OF THE MORNING RAIN WILL LIFT NORTH OF THE MIDLANDS FOR THE AFTERNOON. MILD TEMPERATURES RANGING FROM THE LOWER 60S NORTH AND WEST...TO AROUND 70 SOUTH AND EAST ARE FORECAST TODAY. THE CHANCE FOR RAIN INCREASES AGAIN OVERNIGHT AS THE COLD FRONT AND A WEAK UPPER LEVEL DISTURBANCE ENTERS THE FORECAST AREA. RAINFALL AMOUNTS WILL GENERALLY BE LESS THAN ONE HALF OF AN INCH. SHOULD SEE OVERNIGHT LOWS IN THE 50S UNDER CLOUDY SKIES. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... THE COLD FRONT WILL BE SLOW TO EXIT THE FORECAST AREA AS SEVERAL WEAK WAVES ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY. THE CHANCE FOR RAIN CONTINUES MONDAY...THEN BEGIN TO TAPERS OFF MONDAY NIGHT INTO TUESDAY MORNING AS THE COLD FRONT MOVES OFFSHORE AND DRIER AIR FILTERS IN FROM THE WEST. ABOVE NORMAL TEMPERATURES MONDAY WILL DROP BACK INTO THE 50S FOR TUESDAY. OVERNIGHT LOWS IN THE 40S MONDAY NIGHT WILL COOL INTO THE 30S TUESDAY NIGHT GIVEN MOSTLY CLEAR SKIES AND LIGHT WINDS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... STRONG CANADIAN HIGH PRESSURE WILL REMAIN CENTERED OFF TO THE WEST OF THE FORECAST AREA ON WEDNESDAY...THEN IT WILL GRADUALLY PUSH EASTWARD INTO THE SOUTHEAST ON THURSDAY...THEN PUSH OFF THE COAST INTO FRIDAY. DRY WEATHER IS FORECAST INTO THURSDAY NIGHT... THEN MOISTURE IS EXPECTED TO RETURN THROUGH THE DAY FRIDAY AS A WARM FRONT LIFTS NORTHWARD FROM THE GULF COAST STATES. MODELS INCREASE RAIN CHANCES FRIDAY INTO SATURDAY...AND HAVE GENERALLY GONE WITH CHANCE POPS FOR THAT TIME FRAME. ALTHOUGH TEMPERATURES WILL BE ON THE COLD SIDE WEDNESDAY INTO FRIDAY...TEMPS WILL INCREASE FRIDAY INTO SATURDAY...WHICH WILL KEEP READINGS WARM ENOUGH THAT THE PRECIP WILL BE ALL LIQUID. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... 88D SHOWS A BAND OF SHOWERS WITH ISOLATED THUNDERSTORMS STRETCHING FROM CENTRAL AL NORTHEAST ACROSS NRN GA INTO THE NW HALF OF SC. CURRENT RADAR TRENDS WILL TAKE THE BULK OF THE PRECIPITATION NW OF THE TAF SITES...BUT SOME LIGHT RAIN IS STILL POSSIBLE THROUGH THE MORNING AS AGS/DNL/CAE/CUB ARE ON THE EASTERN FRINGE OF THE PRECIPITATION SHIELD. THIS AGREES WITH MODELS TAKING BEST ISENTROPIC LIFT ACROSS THE UPSTATE. CLOUD BASES HAVE LOWERED TO MVFR AT ALL TAF SITES EXCEPT FOR OGB. MODEL GUIDANCE SUGGEST THAT CLOUD BASES WILL CONTINUE TO LOWER ACROSS THE MIDLANDS/CSRA THIS MORNING AND EXPECT ALL TAF SITES TO BECOME MVFR AND REMAIN SO THROUGH THE REMAINDER OF THE PERIOD. LATEST HRRR INDICATE THAT LIGHT RAIN ACROSS THE MIDLANDS AND CSRA WILL MOVE NORTHEAST OF THE TAF SITES BY MID/LATE MORNING. TO MVFR THIS MORNING AS THE ATMOSPHERE BECOME MORE MOIST. ISENTROPIC LIFT WILL ONCE AGAIN INCREASE TONIGHT AROUND/AFTER MIDNIGHT AS A COLD FRONT MOVES CLOSER TO THE REGION FROM THE WEST. EXPECT AN INCREASING CHANCE FOR SHOWERS AFTER 06Z. HAVE CONTINUED WITH A MENTION OF LIGHT RAIN/VCSH IN THE TAFS OVERNIGHT WITH LOWERING CEILINGS AND VSBYS. NEAR CALM WINDS SHOULD BECOME SOUTH TO SOUTHWEST AROUND 5 KNOTS AFTER SUNRISE AND CONTINUE THROUGH THE DAY. WINDS WILL WEAKEN BY SUNSET AND BE LIGHT THROUGH THE REMAINDER OF THE FORECAST EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE TONIGHT THROUGH EARLY TUESDAY AS THE NEXT FRONTAL SYSTEM MOVES INTO THE AREA AND STALLS JUST TO THE SOUTH. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR SCZ030. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
611 AM EST SUN DEC 28 2014 .SYNOPSIS... HIGH PRESSURE WILL PULL FURTHER OFFSHORE TODAY. A COLD FRONT WILL SLOWLY MOVE THROUGH THE REGION LATE MONDAY AND MONDAY NIGHT. HIGH PRESSURE WILL THEN BUILD INTO THE AREA TUESDAY THROUGH THURSDAY... BEFORE MOVING INTO THE ATLANTIC LATE IN THE WEEK. A COLD FRONT COULD APPROACH NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE CENTERED WELL OFFSHORE OF THE NORTH CAROLINA OUTER BANKS WILL SHIFT FARTHER OUT INTO THE ATLANTIC TODAY AS A COLD FRONT APPROACHES FROM THE WEST. A VERY WEAK COASTAL TROUGH NOTED OVER THE GULF STREAM YESTERDAY EVENING HAS DISSIPATED WITH THE LOW-LEVEL WIND FIELD OVER THE LOCAL MARINE AREA NOW SOUTHWEST VERSUS NORTHEAST. THE EXPANSIVE UPPER RIDGE THAT IS IN PLACE ALOFT WILL NUDGE EAST TODAY A POTENT SHORTWAVE OVER THE SOUTHERN ROCKIES/ 4-CORNERS REGION DIGS INTO NORTHERN MEXICO AND THE EDWARDS PLATEAU OF TEXAS. THERE LOOKS TO BE ENOUGH RIDING BOTH AT THE SURFACE AND ALOFT TO KEEP THE PRIMARY MOISTURE CONVEYOR AHEAD OF THE COLD FRONT TO THE WEST TODAY...THUS KEEPING DRY CONDITIONS IN PLACE FOR ALL OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. IT WILL BE WARM DAY AS 850 HPA TEMPERATURES RISE TO +12C TO +14C... ALTHOUGH MID/HIGH LEVEL CLOUDINESS WILL TEMPER THE WARMTH POTENTIAL SOMEWHAT. IT WILL STILL BE A VERY WARM DAY FOR LATE DECEMBER WITH HIGHS RISING INTO THE MID 70S AWAY FROM THE BEACHES. A FEW UPPER 70S WILL BE POSSIBLE FOR AREAS CLOSEST TO THE ALTAMAHA RIVER AS MORE BREAKS IN THE CLOUD COVER ARE EXPECTED TO OCCUR THERE. IMMEDIATE BEACH LOCATIONS WILL LIKELY STRUGGLE TO REACH THE LOWER 60S DUE TO THE PROXIMITY OF CHILLY ATLANTIC SHELF WATERS IN THE MID 50S AND POSSIBLY SEA FOG. THERE IS A POTENTIAL FOR SIGNIFICANT SEA FOG DEVELOPMENT OVER THE COASTAL WATERS TODAY AS WARM/MOIST AIR BEGINS TO FLOW OVER THE CHILLY SHELF WATERS THAT ARE IN PLACE OFF THE COAST. THE SYNOPTIC MODELS HAVE BEEN HINTING AT SEA FOG DEVELOPMENT FOR QUITE SOME TIME...ALTHOUGH ITS ONSET AND EXTENT IS STILL IN QUESTION. CONDITIONS CERTAINLY LOOK RIPE FOR WIDESPREAD SEA FOG DEVELOPMENT... SIMILAR TO WHAT HAS BEEN SEEN OVER THE PAST SEVERAL WEEKS DURING WARM PERIODS. ANY SEA FOG THAT FORMS OFFSHORE COULD CERTAINLY BEGIN TO MOVE INLAND THIS AFTERNOON AS A SEA BREEZE CIRCULATION TAKES HOLD ALONG THE COAST. DEPENDING ON HOW STRONG THE THERMALLY DIRECT CIRCULATION BECOMES...DENSE FOG COULD BE ADVECTED AS FAR INLAND AS THE INTRACOASTAL WATERWAY...CHARLESTON HARBOR AND POSSIBLY THE SAVANNAH RIVER...AFFECTING DOWNTOWN CHARLESTON AND PARTS OF DOWNTOWN SAVANNAH BY LATE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... TONIGHT...MEAN RIDGING WILL LIKELY GIVE WAY ENOUGH OVERNIGHT THAT ISOLATED TO PERHAPS LOW-END SCATTERED SHOWERS COULD IMPACT MAINLY THE CENTRAL AND WESTERN PORTIONS OF THE FORECAST AREA LATE TONIGHT AS A COLD FRONT AND WEAK FRONTAL WAVE APPROACHES. RAINFALL AMOUNTS...IF ANY...WILL BE LIGHT AS MODELS STILL DEPICT A WELL- DEFINED MID-LEVEL CLOUD POCKET HOLDING FIRM. WILL HIGHLIGHT 20-30 PERCENT POPS IN THESE AREAS...ALTHOUGH CONFIDENCE FOR ACTUALLY SEEING MEASURABLE RAINFALL IS LOW. IT WILL BE ANOTHER WARM NIGHT WITH LOWS RANGING FROM THE UPPER 50S INLAND TO THE LOWER 60S COAST. OUR BIGGEST CONCERN TONIGHT IS FOR THE POTENTIAL FOR A WIDESPREAD DENSE SEA FOG EVENT UNFOLDING ACROSS THE AREA. AREAS OF SEA FOG WILL LIKELY BE ONGOING ACROSS THE COASTAL WATERS AND POSSIBLY THE COASTAL COUNTIES AT SUNSET...WHICH SHOULD SPREAD INLAND UNDERNEATH THE NOCTURNAL INVERSION AS THE NIGHT PROGRESSES. IN ADDITION... MODELS SUGGEST A SECONDARY AREA OF SEA FOG AND RADIATION FOG WILL DEVELOP OVER THE NORTHEAST GULF AND FLORIDA PANHANDLE THIS EVENING...THEN GRADUALLY SPREAD IN FROM THE SOUTH AND SOUTHWEST AFTER MIDNIGHT. CONDITIONS CERTAINLY LOOK FAVORABLE FOR WIDESPREAD FOG TO AFFECT MANY AREAS TONIGHT...BUT FORECASTING THE TIMING AND EXTENT OF SEA FOG IS ALWAYS A CHALLENGE. CONFIDENCE IN SEA FOG FORMING IS RATHER HIGH GIVEN EXTENSIVE SEA FOG HAS ALREADY OCCURRED DURING PREVIOUS WARM SPELLS EXPERIENCED OVER THE PAST FEW WEEKS...BUT IT REMAINS TO BE SEEN EXACTLY HOW THIS EVENT WILL PLAY OUT. WILL HIGHLIGHT AREAS OF FOG AND WIDESPREAD FOG ALL AREAS TONIGHT...GRADUALLY SPREADING INLAND AND FROM THE SOUTH OVERNIGHT. THE INTRODUCTION OF DENSE AND VISIBILITY ATTRIBUTES MAY EVENTUALLY BE NEEDED IN THE GRIDDED AND TEXT FORECASTS. A DENSE FOG ADVISORY MAY VERY WELL BE NEEDED FOR SOME AREAS OVERNIGHT AND THIS POTENTIAL WILL REMAIN HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK. MONDAY...WEAKENING SHORTWAVE ENERGY WILL MOVE ACROSS THE MID ATLANTIC AND CAROLINA COASTLINE DURING THE MORNING AND AFTERNOON TIME FRAME. A COLD FRONT WILL SHIFT INTO THE FORECAST AREA AND GRADUALLY SLIP OFF THE SOUTHEAST COAST THROUGH THE EVENING AND OVERNIGHT. ALTHOUGH THE BEST CHANCE OF RAIN DURING THE SHORT TERM PERIOD APPEARS TO OCCUR WITH FRONTAL PASSAGE MONDAY AFTERNOON... PREFER TO CAP POPS BELOW THE LIKELY CATEGORY CONSIDERING SOME UNCERTAINTIES REGARDING COVERAGE. WILL INDICATE RAIN CHANCES PEAKING IN THE 40 PERCENT RANGE TO ACCOUNT FOR SOME FRONTAL CONVERGENCE AND MOISTURE ACCESS...WHILE STILL REMAINING CONSERVATIVE SINCE THE FRONT WILL BE NEARLY PARALLEL TO THE DAMPENING FLOW ALOFT AND SHORTWAVE ENERGY WILL BE IN A WEAKENING STATE. COMPRESSIONAL WARMING IN ADVANCE OF THE COLD FRONT...COMBINED WITH A DOWNSLOPE FLOW COMPONENT...WILL SUPPORT ANOTHER UNSEASONABLY WARM DAY. EXPECT TEMPERATURES TO PEAK IN THE UPPER 60S TO LOW 70S...WHILE LOW TEMPERATURES ARE RELATIVELY MILD IN THE LOW TO MID 50S. TUESDAY...RAIN WILL STEADILY DIMINISH IN COVERAGE FROM NORTHWEST TO SOUTHEAST THROUGH THE MORNING HOURS...AS THE COLD FRONT AND AN ASSOCIATED WAVE OF LOW PRESSURE MOVE FARTHER AWAY FROM THE COAST. RAIN CHANCES WILL FALL BELOW 15 PERCENT BY EARLY AFTERNOON...WITH SKY COVER SLOWLY SCATTERING TOWARD THE EVENING HOURS. COLD ADVECTION AND NORTH FLOW IN THE WAKE OF THE FRONT AND ALONG THE PERIPHERY OF EXPANSIVE HIGH PRESSURE BUILDING FROM THE WEST WILL SUPPORT COOLER AND DRIER CONDITIONS. HIGH TEMPERATURES WILL RANGE FROM THE LOW 60S NORTH TO THE MID 60S SOUTH...WITH NIGHTTIME LOWS FALLING INTO THE UPPER 30S TO LOWER 40S. WEDNESDAY...AN IMPRESSIVELY STRONG AND EXPANSIVE SURFACE HIGH WILL STRETCH ACROSS MUCH OF THE CENTRAL AND EASTERN UNITED STATES BY MID WEEK. EXPECT RATHER QUIET CONDITIONS TO PREVAIL...WITH TEMPERATURES A DEGREE OR TWO BELOW SEASONAL NORMALS. HIGH TEMPERATURES WILL BE IN THE LOW 50S NORTH TO UPPER 50S SOUTH UNDER MOSTLY CLEAR SKIES. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... THE EXPANSIVE SURFACE HIGH WILL STEADILY SHIFT OVER THE SOUTHERN UNITED STATES BY THURSDAY...BEFORE SHIFTING INTO THE ATLANTIC WATERS FRIDAY AND SATURDAY. A STRONG CUT OFF LOW OVER SOUTHERN CALIFORNIA THURSDAY MORNING WILL WEAKEN WHILE TRACKING ACROSS THE SOUTHWEST STATES FRIDAY...EVENTUALLY PROVIDING THE NECESSARY ENERGY TO SPIN UP A SURFACE LOW PRESSURE SYSTEM THAT WILL LIFT INTO THE OHIO VALLEY SATURDAY. THE TRAILING COLD FRONT FROM THIS SYSTEM WILL CROSS THE EASTERN UNITED STATES OVER THE WEEKEND. WILL MAINTAIN DRY WEATHER WEDNESDAY NIGHT THROUGH THURSDAY AS HIGH PRESSURE REMAINS IN CONTROL...THEN REINTRODUCE RAIN CHANCES FRIDAY INTO THE WEEKEND TO ACCOUNT FOR THE NEXT FRONTAL SYSTEM. LATEST MODEL SOLUTIONS SUGGEST BEST RAIN POTENTIAL WILL BE SATURDAY...WHEN THE COLD FRONT IS CURRENTLY FORECAST TO BE CROSSING THE REGION. WILL ADVERTISE SEASONAL TEMPERATURES THURSDAY AND FRIDAY...THEN INDICATE A WARMING TREND FRIDAY NIGHT INTO THE WEEKEND AHEAD OF THE APPROACHING FRONT. && .AVIATION /11Z SUNDAY THROUGH THURSDAY/... VFR TODAY ATHOUGH THERE IS A SLIGHT CHANCE FOR A BRIEF PERIOD OF MVFR CIGS AT BOTH KCHS/KSAV JUST AFTER SUNSET IF THE RAP SOUNDINGS PROVE CORRECT. SEA FOG IS EXPECTED TO DEVELOP OFF THE COAST LATER TODAY. SOME OF THIS WILL SPREAD INLAND LATE THIS AFTERNOON WITH THE SEA BREEZE WITH A BIGGER PUSH EXPECTED OVERNIGHT. AT THIS TIME...THE BEST CHANCES FOR SIGNIFICANT IMPACTS LOOKS TO BE AT KCHS...ALTHOUGH PROBABILITIES ARE HIGH AT KSAV AS WELL. WILL TAKE A SOMEWHAT CONSERATIVE APPROACH WITH THE 12Z TAFS SINCE THE TIMING AND EXTENT IS STILL A BIT UNCERTAIN. WILL SHOW MVFR VSBYS/CIGS THIS EVENING...DROPPING TO LIFR AT KCHS BY 06Z WITH HIGH-END IFR AT KSAV. BOTH SITES COULD VERY WELL DROP BELOW AIRFIELD MINIMUMS AFTER 06Z...BUT WILL NOT INTRODUCE THOSE CONDITIONS JUST YET. EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS LIKELY LATE MONDAY INTO MONDAY NIGHT AS A COLD FRONT MOVES ACROSS THE REGION. && .MARINE... TODAY...VARIABLE WINDS WILL GRADUALLY BECOME SOUTH TO SOUTHWEST TODAY AS A COLD FRONT APPROACHES FROM THE WEST. WINDS WILL REMAIN LESS THAN 10 KT THROUGH THE DAY ONCE THE WIND PICKS UP. THERE WILL BE A RISK FOR SEA FOG DEVELOPING TODAY AS WARM/MOIST AIR FLOWS OVER THE CHILLY SHELF WATERS. THE ONSET AND EXTENT OF THE SEA FOG REMAINS IN QUESTIONS...ALTHOUGH MODELS HAVE BEEN HINTING AT THIS FOR SEVERAL RUNS NOW...ESPECIALLY OVER THE GEORGIA AND BEAUFORT COUNTY WATERS WHERE AIR PARCEL RESIDENCE TIMES WILL BE THE LONGEST. WILL LIMIT CONDITIONS TO AREAS OF FOG FOR NOW...ALTHOUGH THE FOG MAY VERY WELL BECOME WIDESPREAD AND DENSE. A MARINE DENSE FOG ADVISORY MAY EVENTUALLY BE NEEDED AND WILL BE ADDRESSED IN THE HAZARDOUS WEATHER OUTLOOK. SEAS WILL AVERAGE 2 FT NEARSHORE AND 3-4 FT OFFSHORE...MAINLY IN LONG PERIOD EAST SWELLS WITH PERIODS OF 15-18 SECONDS. TONIGHT...CONDITIONS LOOK TO FAVOR WIDESPREAD DENSE SEA FOG ACROSS THE NEARSHORE WATERS AS SOUTHWEST WINDS DOMINATE WITH SPEEDS LESS THAN 10 KT. IT IS STILL UNCLEAR EXACTLY HOW WIDESPREAD AND DENSE THE SEA FOG WILL BECOME...BUT CONFIDENCE IS INCREASING THAT A NASTY DENSE SEA FOG EVENT WILL OCCUR. WILL GO AHEAD AND INTRODUCE WIDESPREAD FOG IN THE GRIDDED AND TEXT FORECASTS...BUT NO INTRODUCE DENSE WORDING JUST YET. SEAS WILL AVERAGE 2-3 FT NEARSHORE WATERS AND 3-4 FT OFFSHORE WATERS...MAINLY IN LONG PERIOD EAST SWELL. MONDAY...A COLD FRONT WILL SLIP INTO THE COASTAL WATERS DURING THE EVENING/OVERNIGHT HOURS...ALLOWING SOUTHWEST FLOW EARLY IN THE DAY TO VEER NORTH OVER THE SOUTH CAROLINA WATERS AND NORTHWEST ACROSS GEORGIA MARINE ZONES. SEA FOG WILL PERSIST ACROSS THE NEARSHORE WATERS DURING THIS TIME...MOST LIKELY JUST OUTSIDE OF CHARLESTON AND SAVANNAH HARBORS. HOWEVER...IF WINDS BACK MORE TO THE SOUTH DURING THE DAYTIME PERIOD...FOG COULD IMPACT ONE OR BOTH OF THESE PORTS. TUESDAY THROUGH THURSDAY...AN IMPRESSIVE AREA OF HIGH PRESSURE WILL BUILD ACROSS THE CENTRAL AND EASTERN UNITED STATES EARLY IN THE WEEK...EVENTUALLY SETTLING OVER THE SOUTHEAST COAST BY THURSDAY. THE PRESSURE GRADIENT WILL TIGHTEN ON THE PERIPHERY OF THE BUILDING SURFACE HIGH...AND CONSIDERING SOME COLD ADVECTION IN THE WAKE OF THE DEPARTING COLD FRONT...MARGINAL SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE FOR PORTIONS OF THE WATERS TUESDAY INTO EARLY WEDNESDAY. AS THE CENTER OF THE HIGH SHIFTS TOWARD THE SOUTHEAST STATES THURSDAY...THE PRESSURE GRADIENT WILL WEAKEN SUFFICIENTLY TO ALLOW WINDS/SEAS TO SUBSIDE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
429 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT TO OUR WEST WILL SLOWLY MAKE ITS WAY ACROSS THE AREA TONIGHT AND MONDAY BRINGING THE CHANCE FOR RAIN. DRY WEATHER AND COOLER TEMPERATURES WILL RETURN FOR MID-WEEK AS HIGH PRESSURE DOMINATES ANOTHER COLD FRONT WILL BRING THE THREAT OF RAIN NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... THE UPPER LEVEL FLOW WILL REMAIN HIGHLY AMPLIFIED WITH A RIDGE CENTERED OVER THE BAHAMAS AND CUBA...AND A POSITIVELY TILTED TROUGH EXTENDING FROM THE WESTERN GREAT LAKES REGION INTO WEST TEXAS. AT THE SURFACE...HIGH PRESSURE WAS OVER THE WESTERN ATLANTIC WITH A COLD FRONT EXTENDING FROM THE CENTRAL APPALACHIANS SOUTHWESTWARD TO MISSISSIPPI. DEEP SOUTHWEST FLOW AHEAD OF THE FRONT WILL PUMP MOISTURE INTO OUR AREA TODAY AND TONIGHT. MODELS KEEP MUCH OF THE RAINFALL ACROSS NORTHERN GEORGIA INTO THE UPSTATE OF SOUTH CAROLINA TODAY. WE KEPT THE HIGHEST POPS ACROSS THE WEST...AND DRIER ACROSS THE EAST. MILD TEMPERATURES RANGING FROM THE LOWER 60S NORTH AND WEST...TO AROUND 70 SOUTH AND EAST ARE FORECAST TODAY. THE CHANCE FOR RAIN INCREASES OVERNIGHT AS THE COLD FRONT AND A WEAK UPPER LEVEL DISTURBANCE ENTERS THE FORECAST AREA. RAINFALL AMOUNTS WILL GENERALLY BE LESS THAN ONE QUARTER OF AN INCH. SHOULD SEE OVERNIGHT LOWS IN THE 50S UNDER CLOUDY SKIES. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... THE COLD FRONT WILL BE SLOW TO EXIT THE FORECAST AREA AS SEVERAL WEAK WAVES ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY. THE CHANCE FOR RAIN CONTINUES MONDAY...THEN BEGIN TAPERS TO AN END MONDAY NIGHT INTO TUESDAY MORNING AS THE COLD FRONT MOVES OFFSHORE AND DRIER AIR FILTERS IN FROM THE WEST. ABOVE NORMAL TEMPERATURES MONDAY WILL DROP BACK INTO THE 50S FOR TUESDAY. OVERNIGHT LOWS WILL BE IN THE 40 MONDAY NIGHT WILL COOL INTO THE 30S TUESDAY NIGHT GIVEN MOSTLY CLEAR SKIES AND LIGHT WINDS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... STRONG CANADIAN HIGH PRESSURE WILL REMAIN CENTERED OFF TO THE WEST OF THE FORECAST AREA ON WEDNESDAY...THEN IT WILL GRADUALLY PUSH EASTWARD INTO THE SOUTHEAST ON THURSDAY...THEN PUSH OFF THE COAST INTO FRIDAY. DRY WEATHER IS FORECAST INTO THURSDAY NIGHT... THEN MOISTURE IS EXPECTED TO RETURN THROUGH THE DAY FRIDAY AS A WARM FRONT LIFTS NORTHWARD FROM THE GULF COAST STATES. MODELS INCREASE RAIN CHANCES FRIDAY INTO SATURDAY...AND HAVE GENERALLY GONE WITH CHANCE POPS FOR THAT TIME FRAME. ALTHOUGH TEMPERATURES WILL BE ON THE COLD SIDE WEDNESDAY INTO FRIDAY...TEMPS WILL INCREASE FRIDAY INTO SATURDAY...WHICH WILL KEEP READINGS WARM ENOUGH THAT THE PRECIP WILL BE ALL LIQUID. && .AVIATION /09Z SUNDAY THROUGH FRIDAY/... 88D SHOWS A BAND OF SHOWERS WITH ISOLATED THUNDERSTORMS STRETCHING FROM CENTRAL AL NORTHEAST ACROSS NRN GA INTO THE NW HALF OF SC. CURRENT RADAR TRENDS WILL TAKE THE BULK OF THE PRECIPITATION NW OF THE TAF SITES...BUT SOME LIGHT RAIN IS STILL POSSIBLE THROUGH THE MORNING. THIS IS AGREES WITH MODELS TAKING BEST ISENTROPIC LIFT ACROSS THE UPSTATE. CLOUD BASES HAVE LOWERED TO MVFR AT ALL TAF SITES EXCEPT FOR OGB. MODEL GUIDANCE SUGGEST THAT CLOUD BASES WILL CONTINUE TO LOWER ACROSS THE MIDLANDS/CSRA THIS MORNING AND EXPECT ALL TAF SITES TO BECOME MVFR. LATEST HRRR INDICATE THAT LIGHT RAIN ACROSS THE MIDLANDS AND CSRA WILL MOVE NORTHEAST OF THE TAF SITES BY MID/LATE MORNING. TO MVFR THIS MORNING AS THE ATMOSPHERE BECOME MORE MOIST. ISENTROPIC LIFT WILL ONCE AGAIN INCREASE TONIGHT AROUND/AFTER MIDNIGHT AS A COLD FRONT MOVES CLOSER TO THE REGION FROM THE WEST. EXPECT AN INCREASING CHANCE FOR SHOWERS AFTER 06Z. NEAR CALM WINDS SHOULD BECOME SOUTH TO SOUTHWEST AROUND 5 KNOTS AFTER SUNRISE AND CONTINUE THROUGH THE DAY. EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE TONIGHT THROUGH EARLY TUESDAY AS THE NEXT FRONTAL SYSTEM MOVES INTO THE AREA AND STALLS JUST TO THE SOUTH. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR SCZ030. GA...NONE. && $$ Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 909 PM CST Mon Dec 29 2014 .UPDATE... ISSUED AT 900 PM CST MON DEC 29 2014 The lift being generated in the post frontal airmass has been very weak, based on radar returns and local observations. Have only seen isolated reports of flurries so far. A clearing line just north of the band of clouds/flurries is progressing southward, which would spell an end to the very narrow channel of lift/clouds/flurries. Have updated the sky grids to account for some clearing later tonight at least across the northern counties. Less cloud cover would mean colder lows that we currently have, a bit more toward the colder guidance numbers. Have trimmed a few degrees from lows NW of a line from SPI to BMI. Will keep a mention of flurries in tonight`s forecast following the trek of the band of clouds to the SE. No other significant changes needed this evening. Tomorrow looks like a colder but mostly sunny day. Updated info will be available shortly. && .SHORT TERM...(Tonight) ISSUED AT 315 PM CST MON DEC 29 2014 The 18Z surface analysis indicated the leading edge of the Arctic airmass, ahead of an intense high pressure center in the Canadian Rockies, was sinking just south of I-80. Clouds associated with cold air undercutting were along the I-74 corridor at 20z/2 pm CST. This area of cloudiness, along with low clouds in southern Iowa/northern Missouri will overspread central and eventually southeast Illinois this evening. There should be enough weak forcing for snow flurries, particularly in central Illinois this evening, and the rest of the forecast area late tonight as the short range models point to weak lift just behind the strongest low level cold advection. The HRRR model is trying to produce some measurable snow from Bloomington to near Taylorville between 6 pm and Midnight. At this point, it is the only model, doing this and has most likely latched on to the area of light snow around Pontiac. Will keep an eye on this, but for now will stick to the mention of flurries. The numerical guidance appears to be on the colder side due to less cloud cover and stronger cold advection. Thus, will be going with lows roughly 5 degrees warmer than guidance in central IL and 2-3 degrees warmer in southeast IL due to forecast cloud cover. && .LONG TERM...(Tuesday through Monday) ISSUED AT 315 PM CST MON DEC 29 2014 The narrow band of flurries will continue into Tuesday morning, but should dissipate by afternoon. Behind this area, and strong 1050mb high pressure area will drop into the region. This high will bring dry weather to the area through Thur night, as well as well below normal temps through the period. With the center of the high dropping into the plains Tue night, the coldest temps are expected to be Tue night through Wed. Northwesterly winds Tue night will still be around 10mph, so there could be enough mixing to prevent the bottom from dropping out on the temps. However, single digits are still expected over half of the CWA, and combined with the wind speeds, below zero wind chills are probably Tue night/Wed morning. Beyond this, the high pressure will slide further south into the southern plains by Thursday night. Temps may warm slightly, but only to back around normal. The return of slightly warmer temps and moisture will not occur until the high pressure area move into the southeastern US Thur night and Fri. However, along with this will come the chance of pcpn to the area for the end of the week and the weekend. The questions still remain as to the timing of the pcpn return, how warm it will get, and what p-type will occur. Both the GFS and ECMWF continue to not agree on the overall solution with this system. However, there is some agreement as to how the upper level will evolve into Saturday. The upper level low pressure area will weaken and get lifted out into the flow over the weekend. ECMWF is much quicker with this than the GFS. Models also agree that the pcpn will not really begin until Fri night/Sat morning. However, there still remains a chance of pcpn Friday in the southeast, so will keep chance pops there, though would not be surprised to see this change later. Beyond this, models do not agree with location of pcpn and sfc low pressure area. With the ECMWF being quicker with the upper level system, it keeps the low further south and therefore has very little pcpn in our area...and only in the extreme southeast. The GFS is further north with the low, but has shifted it east since yesterday`s model runs. However, it keeps pcpn over the area through the weekend, just not as much as before; and with the low east, temps may not get as warm, thereby effecting the p-type through the weekend. Will still be keeping the p-type simple and just going with snow, becoming rain or snow, then snow at night and rain and/or snow again during the daytime. The chance of pcpn will continue into Sat night. Sunday and Monday will be dry for now as the system should be well east of the area. Temps in the extended will warm, with the warmest temps being on Saturday and then cooling back off by Monday as another shot of colder air slides into the area. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 543 PM CST MON DEC 29 2014 The arctic front will continue to slide south and east tonight, as it dissipates. Flurries will be the primary precipitation, and will develop behind the front in the region of lift. The RAP and HRRR are both indicating the area of light snow that lowered visibility to 3 miles will drift south through Bloomington and eventually just east of Lincoln toward Taylorville. It is projected to weaken as it shifts south, but Bloomington may see visibility drop to MVFR levels in light snow for a couple of hours. The prevailing cloud cover will lower to MVFR at all TAF sites this evening as the arctic front progresses southeast. The flurries should dissipate late tonight and MVFR clouds will break up starting around 16z at PIA and eventually clearing at DEC around 20z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SHORT TERM...Miller LONG TERM...Auten AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
902 PM CST MON DEC 29 2014 .SHORT TERM... 323 PM CST REMAINDER OF THIS AFTERNOON AND TONIGHT... LAKE EFFECT SNOW HAS LARGELY BEEN A NON-EVENT THIS AFTERNOON... MAINLY DUE TO VERY DRY LOW LEVEL AIR IN PLACE OVER NERN IL/NWRN...WITH DEWPOINTS IN THE UPPER TEENS IN SPITE OF THE NELY FETCH OFF LAKE LAKE MICHIGAN WHERE WATER TEMPERATURES ARE STILL IN THE MIDDLE TO UPPER 30S. THE MAIN IMPACT OF THE LAKE HAS BEEN A BKN-OVC STRATOCU DECK MOVING OFF OF THE LAKE. HOWEVER...THERE HAS BEEN SOME SCT LIGHT SNOW WITH THE COLD FRONT/LEADING EDGE OF THE ARCTIC AIRMASS BUILDING ACROSS THE MISSISSIPPI VALLEY AND INTO THE OHIO VALLEY. WHILE DEEP LAYER MOISTURE HAS BEEN MEAGER...THERE IS JUST ENOUGH FORCING TO SQUEEZE OUT SOME ISOLD AREAS OF LIGHT SNOW...MAINLY OVER PORTIONS OF THE AREA SOUTH OF I-80. FOR THE OVERNIGHT HOURS...AS THE HIGH CONTINUES TO SPREAD SOUTH AND EAST AND THE CENTER OF THE HIGH BUILDS INTO THE NRN PLAINS/NRN ROCKIES...LOW LEVEL FLOW SHOULD GRADUALLY BACK THROUGH NLY TO WNWLY. THE LONGER LAKE FETCH WHEN WINDS BECOME NLY COULD STILL HELP BRING SOME LAKE EFFECT SNOW SHOWERS TO NWRN INDIANA...BUT HAVE BACKED OFF ON QPF/SNOW AMOUNTS...WHILE MAINTAINING THE LIKELY POPS...WITH THE IDEA OF A HIGH POP-LOW QPF SCENARIO. SO...STILL THINK THERE COULD BE SOME ACCUMULATING LAKE EFFECT SNOW OVER PORTIONS OF NWRN INDIANA NEAR THE LAKE...BUT AMOUNTS WILL LIKELY BE LIGHT. AS THE ARCTIC AIRMASS CONTINUES TO SPREAD SOUTH AND EAST...EXPECT LOWS TONIGHT TO DROP TO NEAR 10F OVER THE ROCKFORD AREA...WHILE LOCATIONS EAST OF THE I-55 CORRIDOR SHOULD BE IN THE UPPER TEENS TO LOWER 20S. KREIN && .LONG TERM... 323 PM CST TUESDAY THROUGH MONDAY... WHILE A COOLING TREND INITIATED BEGAN SUNDAY FOLLOWING THE PASSAGE OF A COLD FRONT LATE SATURDAY...THE MORE SIGNIFICANT COOLING TREND IS NOW UNDERWAY AS THE TRUE ARCTIC AIRMASS SPREADS ACROSS THE REGION. AS OF 3PM CST MONDAY AFTERNOON...TEMPERATURES IN THE NORTHERN PLAINS RANGED FROM THE SINGLE DIGITS ABOVE 0F TO THE SINGLE DIGITS BELOW ZERO WITH DEWPOINTS OF -10 TO -15F. THE COLD AIR IS STILL EXPECTED TO SPREAD ACROSS THE LOCAL AREA...BUT THE COLDEST AIR SHOULD REMAIN TO THE WEST...OVER THE PLAINS AS THE CENTER OF THE HIGH DROPS FROM THE NORTHERN ROCKIES TONIGHT TO THE LOWER MISSISSIPPI VALLEY BY THURSDAY MORNING. CONDITIONS ACROSS THE AREA SHOULD GENERALLY BE DRY THROUGH THURSDAY...WITH BELOW NORMAL TEMPERATURES AND AMPLE SUNSHINE AS THE SFC HIGH PRESSURE BUILDS ACROSS THE REGION. STILL ANTICIPATE THAT THE LOWEST TEMPERATURES SHOULD BE TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE SFC RIDGE AXIS BUILDS ACROSS THE AREA. WILL CARRY MIN TEMPS FOR WEDNESDAY MORNING IN THE SINGLE DIGITS FOR THE ENTIRE CWA...RANGING FROM ARND 3F OVER THE ROCKFORD AREA TO 8-9F EAST OF THE I-57 CORRIDOR. THERE IS SOME CONCERN THAT THE TEMP FORECAST MAY BE A BIT TOO LOW...CONSIDERING WINDS SHOULD REMAIN 5-10 MPH OVERNIGHT AND THERE IS NO SNOW COVER. HOWEVER...EVEN THOUGH THE AIRMASS WILL BE VERY DRY AND SKIES SHOULD BE MOSTLY CLEAR...EXPECT THAT THE LOWER TEMPERATURES WILL BE MORE DRIVEN BY ADVECTION OF COLDER AIR FROM THE CENTRAL PLAINS...WITH THE CENTER OF A 1050MB HIGH WILL BE CENTERED ALONG THE KANSAS COLORADO BORDER...WITH A RIDGE AXIS EXTENDING TO THE EAST ACROSS CNTRL ILLINOIS AND INTO THE UPPER OHIO VALLEY. WITH A DIGGING TROUGH DROPPING THROUGH SCNTRL CANADA...A MODEST WLY GRADIENT WILL BE IN PLACE...KEEPING WINDS FROM BECMG CALM. SO...EVEN THOUGH THERE IS NO SNOW COVER OR CALM WINDS TO ALLOW FOR STRONG RADIATIVE COOLING TO CAUSE THE TEMPERATURES TO DROP INTO THE SINGLE DIGITS...FEEL THAT THERE WILL BE ENOUGH ADVECTION OF COLD AIR FROM THE CNTRL PLAINS TO BRING THE LOW TEMPERATURES. THE MAIN IMPACT OF THIS COLD AIR AND RELATIVELY BREEZY CONDITIONS WILL BE FOR WIND CHILL READINGS TO DROP TO -5 TO -13 ACROSS THE CWA...WHICH WOULD THE COLDEST SINCE LATE NOVEMBER. THE OTHER FORECAST CONCERN FOR THE EXTENDED FORECAST PERIOD WILL BE ASSOCIATED WITH A CLOSED LOW EXPECTED TO DROP INTO THE DESERT SOUTHWEST WEDNESDAY AND WEDNESDAY NIGHT AS A STRONG PACIFIC SHORTWAVE DROPS DOWN THE WEST COAST. THE MODELS HAVE BEEN VERY CONSISTENT ON THE DEVELOPMENT OF THIS FEATURE...BUT THERE IS STILL A VARIETY OF SOLUTIONS FROM THE VARIOUS MODELS IN THE TIMING OF EJECTING THE SYSTEM OUT OF THE SRN ROCKIES AND TRACKING ACROSS THE SOUTHERN PLAINS AND THEN LIFTING INTO THE OHIO VALLEY. THE GFS/GEM REMAIN ON THE FASTER END OF THE FORECAST ENVELOPE WHILE THE ECMWF IS THE CONSISTENTLY SLOWER SOLUTION. WHILE THE SLOWER SOLUTION IS STILL FAVORED...CONFIDENCE IS STILL LOW THAT THE EVENTUAL PROGRESSION OF THE SYSTEM COULD STILL BE SLOWER THAN WHAT THE ECMWF CONTINUES TO INDICATE. SO...WILL MAINTAIN THE IDEA OF A SLOWER SOLUTION. THE MAIN TREND FOR THE SENSIBLE WEATHER FEATURES SHOULD BE A WARMING TREND WITH MAX TEMPS REBOUNDING INTO THE 30S FOR FRIDAY AND SATURDAY AS UPPER HEIGHTS RISE IN ADVANCE OF THE UPPER LOW EJECTING OUT OF THE DESERT SOUTHWEST. THERE IS DECENT CONFIDENCE IN THIS GENERAL TREND. THERE IS ALSO DECENT CONFIDENCE IN THE IDEA OF INCREASING POPS INTO THE WEEKEND...WHICH IS SLOW THAN PREVIOUSLY FORECAST AND IN LINE WITH A SLOWER PROGRESSION OF THE SYSTEM. HOWEVER THERE IS RELATIVELY LOW CONFIDENCE IN TIMING AND AMOUNT OF PCPN AS THERE IS STILL THE CHANCE FOR SOME PHASING OF THE SRN STREAM SYSTEM WITH NRN STREAM SHORT WAVE ENERGY DROPPING OUT OF THE NRN PLAINS AND ACROSS THE GREAT LAKES. SO...WILL LIMIT POPS TO CHANCE LEVELS FOR NOW WITH THE TREND TO DELAY THE ONSET OF ANY PCPN INTO LATER IN THE FORECAST PERIOD. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * NORTH WINDS BECOMING NORTH-NORTHWEST TONIGHT. //DISCUSSION...UPDATED 00Z... MODIFIED ARCTIC HIGH PRESSURE IS BUILDING INTO THE UPPER PLAINS RESULTING IN NORTH-NORTHEAST WINDS OVER THE TAF SITES EARLY THIS EVE BECOMING MORE NORTH-NORTHWEST BY LATE EVE. THE FLOW OFF THE LAKE FOR ORD AND MDW SHOULD KEEP SPEEDS FLUCTUATING SOME BETWEEN 7-11 KT BASED ON TRENDS OF OBSERVATIONS AND HIGH-RESOLUTION MODEL DATA. PATCHY CIGS BELOW 4000 FT WILL CONTINUE THIS EVE WITH MID- CLOUD ABOVE THAT. AS DRIER AIR WORKS IN LATER TONIGHT ALL OF THIS SHOULD BE SHUNTED SOUTH WITH THE EXCEPTION OF GYY RECEIVING LAKE- EFFECT INSTABILITY AND CLOUDS. SOME LIGHT LAKE-EFFECT SNOW IS POSSIBLE INTO GYY AS WELL BUT IS NOT EXPECTED TO ACCUMULATE. TUESDAY SHOULD SEE MAINLY ONLY HIGH CLOUDS WITH NORTHWEST WINDS AROUND 10-12 KT AS THE HIGH PRESSURE SETTLES SOUTH INTO THE CENTRAL PLAINS. //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM-HIGH IN WINDS. //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR. STIFF SOUTHWEST WINDS. THURSDAY-FRIDAY...VFR. WEST-SOUTHWEST WINDS. SATURDAY-SUNDAY...CHANCE OF SNOW AND IFR. MTF && .MARINE... 304 PM CST NORTH TO NORTHWEST WINDS PERSIST ACROSS THE LAKE TONIGHT...THEN GRADUALLY BACK SOUTHWEST BY WEDNESDAY AND INCREASE TO GALES BY WEDNESDAY AFTERNOON OR EVENING. IT IS NOT CERTAIN HOW EFFECTIVELY THESE SOMEWHAT MILDER SOUTHWEST WINDS WILL SUPPORT STRONG GALES OVER THE COLD WATER...BUT GALES DO APPEAR LIKELY. UNTIL WINDS TURN AWAY FROM NORTH AND NORTHWEST...CONDITIONS WILL BE FAVORABLE FOR SMALL CRAFT HEADLINES FOR THE FIRST HALF OF THE WEEK...AND ESPECIALLY IN THE INDIANA NEARSHORE WATERS. LENNING && .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 NATIONAL WEATHER SERVICE LINCOLN IL 543 PM CST Mon Dec 29 2014 .SHORT TERM...(Tonight) ISSUED AT 315 PM CST MON DEC 29 2014 The 18Z surface analysis indicated the leading edge of the Arctic airmass, ahead of an intense high pressure center in the Canadian Rockies, was sinking just south of I-80. Clouds associated with cold air undercutting were along the I-74 corridor at 20z/2 pm CST. This area of cloudiness, along with low clouds in southern Iowa/northern Missouri will overspread central and eventually southeast Illinois this evening. There should be enough weak forcing for snow flurries, particularly in central Illinois this evening, and the rest of the forecast area late tonight as the short range models point to weak lift just behind the strongest low level cold advection. The HRRR model is trying to produce some measurable snow from Bloomington to near Taylorville between 6 pm and Midnight. At this point, it is the only model, doing this and has most likely latched on to the area of light snow around Pontiac. Will keep an eye on this, but for now will stick to the mention of flurries. The numerical guidance appears to be on the colder side due to less cloud cover and stronger cold advection. Thus, will be going with lows roughly 5 degrees warmer than guidance in central IL and 2-3 degrees warmer in southeast IL due to forecast cloud cover. && .LONG TERM...(Tuesday through Monday) ISSUED AT 315 PM CST MON DEC 29 2014 The narrow band of flurries will continue into Tuesday morning, but should dissipate by afternoon. Behind this area, and strong 1050mb high pressure area will drop into the region. This high will bring dry weather to the area through Thur night, as well as well below normal temps through the period. With the center of the high dropping into the plains Tue night, the coldest temps are expected to be Tue night through Wed. Northwesterly winds Tue night will still be around 10mph, so there could be enough mixing to prevent the bottom from dropping out on the temps. However, single digits are still expected over half of the CWA, and combined with the wind speeds, below zero wind chills are probably Tue night/Wed morning. Beyond this, the high pressure will slide further south into the southern plains by Thursday night. Temps may warm slightly, but only to back around normal. The return of slightly warmer temps and moisture will not occur until the high pressure area move into the southeastern US Thur night and Fri. However, along with this will come the chance of pcpn to the area for the end of the week and the weekend. The questions still remain as to the timing of the pcpn return, how warm it will get, and what p-type will occur. Both the GFS and ECMWF continue to not agree on the overall solution with this system. However, there is some agreement as to how the upper level will evolve into Saturday. The upper level low pressure area will weaken and get lifted out into the flow over the weekend. ECMWF is much quicker with this than the GFS. Models also agree that the pcpn will not really begin until Fri night/Sat morning. However, there still remains a chance of pcpn Friday in the southeast, so will keep chance pops there, though would not be surprised to see this change later. Beyond this, models do not agree with location of pcpn and sfc low pressure area. With the ECMWF being quicker with the upper level system, it keeps the low further south and therefore has very little pcpn in our area...and only in the extreme southeast. The GFS is further north with the low, but has shifted it east since yesterday`s model runs. However, it keeps pcpn over the area through the weekend, just not as much as before; and with the low east, temps may not get as warm, thereby effecting the p-type through the weekend. Will still be keeping the p-type simple and just going with snow, becoming rain or snow, then snow at night and rain and/or snow again during the daytime. The chance of pcpn will continue into Sat night. Sunday and Monday will be dry for now as the system should be well east of the area. Temps in the extended will warm, with the warmest temps being on Saturday and then cooling back off by Monday as another shot of colder air slides into the area. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 543 PM CST MON DEC 29 2014 The arctic front will continue to slide south and east tonight, as it dissipates. Flurries will be the primary precipitation, and will develop behind the front in the region of lift. The RAP and HRRR are both indicating the area of light snow that lowered visibility to 3 miles will drift south through Bloomington and eventually just east of Lincoln toward Taylorville. It is projected to weaken as it shifts south, but Bloomington may see visibility drop to MVFR levels in light snow for a couple of hours. The prevailing cloud cover will lower to MVFR at all TAF sites this evening as the arctic front progresses southeast. The flurries should dissipate late tonight and MVFR clouds will break up starting around 16z at PIA and eventually clearing at DEC around 20z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Miller LONG TERM...Auten AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1131 AM CST SUN DEC 28 2014 .SHORT TERM... 236 AM CST THROUGH MONDAY... HIGH PRESSURE NOSING IN FROM THE WEST RESULTING IN GRADUAL CLEARING FROM WEST TO EAST EARLY THIS MORNING WITH THE BACK EDGE ALREADY THOROUGH ROCKFORD. ONCE THE LOW CLOUDS CLEAR EXPECT SOME PASSING HIGH CLOUDS THIS MORNING EMANATING FROM A MODEST UPPER LOW IN TEXAS...OTHERWISE IT WILL BE A SEASONAL MOSTLY SUNNY DAY WITH HIGHS TOPPING OUT IN THE LOW 30S OR SO. WE`LL HOLD A WEST WIND WHICH WILL MAKE IT FEEL A LITTLE COOLER...THOUGH TODAY LOOKS TO BE THE WARMEST FOR THE REST OF 2014. ARCTIC HIGH PRESSURE CONTINUES TO SINK INTO THE CENTER OF THE COUNTRY TONIGHT. LOCALLY...OUR WINDS TURN NORTHERLY ALLOWING SOME OF THIS CONTINUE MOVING IN. ZONAL FLOW ALOFT WILL KEEP SOME HIGHER CLOUDS PUSHING INTO THE REGION PREVENTING A REAL COLD NIGHT...BUT STILL THE COLDEST WE/VE SEEN IN A WHILE WITH LOWS INTO THE 20S. BY MONDAY MORNING...A BACKDOOR FRONT MOVING DOWN THE LAKE WILL CONTINUE THE STREAM OF COLDER AIR. ADDITIONALLY LAKE EFFECT CLOUDS WILL MOVE INTO NORTHWEST INDIANA AND PORTIONS OF NORTHEAST ILLINOIS. WITH THE CONTINUED COLD ADVECTION AND MIX OF LOW AND MID CLOUD...TEMPS WILL STRUGGLE TO GET TO FREEZING IN MANY SPOTS. NAM IS STILL HINTING AT SOME LAKE EFFECT FLURRIES OR LIGHT SNOW SHOWERS THOUGH LAKE EFFECT PARAMETERS DURING THE DAY ARE NOT SUPER IMPRESSIVE. KMD && .LONG TERM... 236 AM CST MONDAY NIGHT THROUGH SATURDAY... MONDAY NIGHT...A MORE SIGNIFICANT SURGE OF COLD AIR COMES STREAMING IN. THIS WILL ENHANCE LAKE EFFECT PARAMETERS...ESPECIALLY IN NORTHWEST INDIANA AND PORTIONS OF SOUTHERN COOK COUNTY. EQUILIBRIUM LEVELS ARE NOT MUCH BETTER THAN DURING THE DAY MONDAY...BUT LOW LEVEL LAPSE RATES/LAKE INDUCED CAPE ARE SLIGHTLY BETTER TO SUPPORT SOME LIGHT ACCUMULATIONS...ESPECIALLY AFTER MIDNIGHT IN NW INDIANA. AS THE ARCTIC HIGH CONTINUES SOUTH INTO THE PLAINS...WINDS WILL BACK TO NW AND PUSH LAKE EFFECT SNOWS EASTWARD. 850 TEMPS IN THE MINUS TEENS SUPPORT HIGHS ONLY IN THE UPPER TEENS TO LOW 20S IN SPITE OF SOME CLEARING THROUGH THE DAY. TUESDAY NIGHT/WEDNESDAY MORNING FEATURE THE COLDEST AIR MASS. NW FLOW PERSISTS WITH MIGRATORY SHORTWAVE ENERGY. WINDS WILL BACK TO THE WSW THROUGH THE DAY. GIVEN THE COLD START...EXPECT HIGHS SIMILAR TO TUESDAY AND POSSIBLY A BIT COOLER WITH 20 BEING A STRETCH IN PLACES. BY THURSDAY THE UPPER FLOW PATTERN WILL MODIFY AS THE DEEP COLD TROUGH EXTENDING FROM NORTHERN ONTARIO BACK SOUTHWEST TO THE PACIFIC GETS PINCHED OFF IN THE NORTH AND SHIFTS EAST OUR FOCUS THEN SHIFTS TO A CUT OFF LOW OVER CALIFORNIA. SOUTHERLY FLOW AHEAD OF THIS SYSTEM WILL TRANSPORT SOME SLIGHTLY WARMER AIR ALONG WITH ADDITIONAL GULF MOISTURE. MEANWHILE...THE SHORTWAVE ENERGY WILL CONTINUE TO ROTATE SOUTH AND WEST AROUND THE ARCTIC VORTEX THAT AT THIS POINT SETS UP NORTH OF HUDSON BAY. THE CALI LOW WILL EVENTUALLY EJECT EAST AND NORTH FRIDAY INTO SATURDAY. THE CLASH OF THE WARMER GULF AIR AND ARCTIC AIR ENTRENCHED OVER THE REGION LOOKS TO RESULT IN A DYNAMIC WINTER STORM SYSTEM. PRECIP TYPE WILL BE AN ISSUE SOMEWHERE IN THE REGION AHEAD OF THE LOW...WITH AN IMPRESSIVE DEFORMATION SNOW BAND EXPECTING TO SET UP BEHIND IT DUE TO A REPLENISHMENT OF COLD AIR AND STRONG BAROCLINIC ZONE. A LOT HINGES ON THE INTERACTION WITH THE NORTHERN STREAM AS TO WHERE THIS SYSTEM HEADS...BUT MODELS TO THIS POINT HAVE BEEN SOMEWHAT CONSISTENT ON THE TIME FRAME OF CONCERN BEING LATER FRIDAY AND ESPECIALLY INTO SATURDAY WITH SOME WINTRY PRECIPITATION SOMEWHERE IN OUR AREA. COLD AIR COMES RIGHT BACK IN BEHIND IT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * LAKE EFFECT FLURRIES POSSIBLE MONDAY MORNING. * MVFR CIGS MONDAY. JEE //DISCUSSION...UPDATED 18Z... HIGH PRESSURE OVER THE AREA WILL RESULT IN LIGHT WINDS ACROSS THE REGION THROUGH TONIGHT. WINDS TURN NORTH TO NORTHEAST OVERNIGHT WITH LAKE EFFECT SNOW PUSHING ONSHORE. GYY HAS THE BEST CHANCE OF SEEING VIS RESTRICTIONS DUE TO SNOW SO HAVE A TEMPO FOR LOW END MVFR VSBY...AND VSBY COULD BE LOWER. FLURRIES ARE EXPECTED AT MDW AND ORD. MEDIUM CONFIDENCE IN THE LAKE EFFECT SNOW SET UP AND HOW FAR INLAND ACCUMULATING SNOW WILL FALL. MVFR CIGS ALSO MOVE IN OFF OF THE LAKE AND IMPACT THE EASTERN TERMINALS...AND HAVE MEDIUM CONFIDENCE IN MVFR CIGS REMAINING EAST OF DPA. HIGH CONFIDENCE IN MVFR CIGS AT MDW...ORD...AND GYY. JEE //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM CONFIDENCE IN LAKE EFFECT FLURRIES. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR CIGS/LAKE EFFECT SNOW SHOWERS POSSIBLE. TUESDAY THROUGH FRIDAY...SLIGHT CHANCE OF MVFR CIGS AT TIMES OTHERWISE VFR. FRIDAY NIGHT AND SATURDAY...CHANCE OF SNOW AND IFR. IZZI && .MARINE... 150 AM CST MODERATE NORTHWEST WINDS WILL EASE SOME TODAY AND THEN VEER MORE NORTHERLY TONIGHT INTO MONDAY. NORTHERLY WINDS WILL FRESHEN UP MONDAY NIGHT INTO TUESDAY AS ARCTIC AIR SPILLS INTO THE REGION. WINDS WILL BACK TO SOUTHWEST AND INCREASE FURTHER TO GALES WEDNESDAY AND CONTINUE THROUGH THURSDAY MORNING AND STRONG LOW PRESSURE MOVES SOUTH INTO HUDSON BAY TIGHTENING UP THE PRESSURE GRADIENT WITH ARCTIC AIR FIRMLY ENTRENCHED OVER THE AREA. WINDS LOOK TO SUBSIDE LATER THURSDAY INTO EARLY FRIDAY BEFORE POTENTIALLY RAMPING UP AGAIN NEXT WEEKEND AS ANOTHER STORM SYSTEM POTENTIALLY APPROACHES THE REGION THOUGH SIGNIFICANT MODEL DIFFERENCES EXIST IN TRACK AND INTENSITY OF THAT SYSTEM. IZZI && .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 NATIONAL WEATHER SERVICE LINCOLN IL 1058 AM CST Sun Dec 28 2014 .UPDATE... ISSUED AT 1054 AM CST SUN DEC 28 2014 High pressure settling into the FA this morning, but llvl clouds trapped under the overnight inversion are slow to erode. NW of I-55 in Central Illinois is only covered with cirrus this morning...while SE Illinois has stratus under 2000 ft. Cold arctic air settling into the region behind yesterdays cold front resulting in a chilly morning. Temperatures on track with only a few changes to the hourlys... and no large updates are anticipated. && .SHORT TERM...(Today) ISSUED AT 305 AM CST SUN DEC 28 2014 Main short-term challenge will be timing of the clearing trend today. 08z/2am IR satellite imagery shows low clouds covering much of central Illinois, except across the far northern KILX CWA from Peoria northward where clouds have eroded. The 06z NAM 1000-850mb RH field has a good handle on the current cloud cover, so have generally followed its solution for sky cover today. End result will be clearing skies along the I-74 corridor by mid to late morning, with clouds lingering into the afternoon further south. Skies will become mostly clear across the board by late afternoon as high pressure builds in from the west. High temperatures will be near normal for this time of year in the middle to upper 30s. && .LONG TERM...(Tonight through Saturday) ISSUED AT 305 AM CST SUN DEC 28 2014 Quiet weather is expected for the next several days before a storm system gradually approaches from the southwest by the end of the week. High pressure will control the weather across central Illinois on Monday, resulting in cool/dry conditions with highs in the 30s. Meanwhile, a significant chunk of cold air currently in place across central/western Canada will sink southward into the central CONUS by the middle of the week. Models have been hinting at some light snow/flurries as CAA increases Monday night into Tuesday, with the NAM being more aggressive with potential QPF. NAM time-height cross-sections reveal stronger lift within a deeper moist layer than the GFS indicates. Think the low-level moisture may be a bit overdone on the NAM, so am leaning toward the GFS solution here. Even with drier air below 850mb, think lift will be strong enough to warrant mention of a few flurries Monday night and perhaps even into Tuesday morning before moisture profile thins and high pressure builds into the region. Heart of the cold airmass will arrive Tuesday night into Wednesday, when overnight lows dip into the single digits and teens and highs only reach the lower to middle 20s. Once high slowly begins to shift eastward, attention turns to a developing southern-stream storm system associated with a cut-off upper low over the Desert Southwest. Models are still displaying a typical spread of solutions that far out, but confidence is growing that a precipitation event will impact central Illinois by the end of the week. Both the GFS and ECMWF show surface low pressure developing over the Texas panhandle by Friday evening, then lifting northeastward into the Great Lakes on Saturday. While their tracks are not in perfect agreement, a N/NW trend is becoming apparent. GFS takes the low west of the CWA to near Moline by 12z Sat, while the ECMWF tracks the low to near Champaign. Both tracks are further N/NW than previous runs, which suggests precip may be more in the form of rain or a rain/snow mix across the area than previously thought. Based on GFS forecast soundings, if precip is able to spread northward into the initially cold/dry airmass Friday morning, light snow will be the primary precip type. As temps warm into the middle to upper 30s, the snow will likely mix with rain across much of the area by Friday afternoon. Precip will likely remain quite light during the day Friday, with widespread precip holding off until Friday night when airmass saturates and stronger lift arrives. At this point, will carry rain along/south of I-70...a rain/snow mix across the middle of the CWA...and snow along/north of a Rushville to Bloomington line Friday night into Saturday. The track of the system will likely change with successive model runs, so precip type and any potential snow accumulations still remain uncertain. && .AVIATION...(For the 12Z TAFS through 12Z Monday morning) ISSUED AT 532 AM CST SUN DEC 28 2014 Main concern across the central Illinois terminals through the 12Z TAF valid time regards the disposition of the MVFR CIGS today as high pressure builds into the area. Once the low clouds clear out, VFR conditions will prevail through the remainder of the period. The low cloud clearing trends today are tough to pinpoint as the back edge of the cloud deck is far from smooth. Actually, the back edge of the cloud deck is ragged, which should allow for skies to go back/forth between BKN/OVC and SCT for a few hours before finally clearing. The recent progression of the low clouds has become difficult to track on satellite imagery due to a cirrus shield moving over top of the low clouds. However, as best as I can tell, the HRRR has a pretty good handle on the trends, and will lean on it for clearing trends this morning into early afternoon. Northwest winds will continue to diminish in speed as a weak area of high pressure approaches today, eventually leading to light/variable winds tonight. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Bak
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
801 AM CST SUN DEC 28 2014 .SHORT TERM... 236 AM CST THROUGH MONDAY... HIGH PRESSURE NOSING IN FROM THE WEST RESULTING IN GRADUAL CLEARING FROM WEST TO EAST EARLY THIS MORNING WITH THE BACK EDGE ALREADY THOROUGH ROCKFORD. ONCE THE LOW CLOUDS CLEAR EXPECT SOME PASSING HIGH CLOUDS THIS MORNING EMANATING FROM A MODEST UPPER LOW IN TEXAS...OTHERWISE IT WILL BE A SEASONAL MOSTLY SUNNY DAY WITH HIGHS TOPPING OUT IN THE LOW 30S OR SO. WE`LL HOLD A WEST WIND WHICH WILL MAKE IT FEEL A LITTLE COOLER...THOUGH TODAY LOOKS TO BE THE WARMEST FOR THE REST OF 2014. ARCTIC HIGH PRESSURE CONTINUES TO SINK INTO THE CENTER OF THE COUNTRY TONIGHT. LOCALLY...OUR WINDS TURN NORTHERLY ALLOWING SOME OF THIS CONTINUE MOVING IN. ZONAL FLOW ALOFT WILL KEEP SOME HIGHER CLOUDS PUSHING INTO THE REGION PREVENTING A REAL COLD NIGHT...BUT STILL THE COLDEST WE/VE SEEN IN A WHILE WITH LOWS INTO THE 20S. BY MONDAY MORNING...A BACKDOOR FRONT MOVING DOWN THE LAKE WILL CONTINUE THE STREAM OF COLDER AIR. ADDITIONALLY LAKE EFFECT CLOUDS WILL MOVE INTO NORTHWEST INDIANA AND PORTIONS OF NORTHEAST ILLINOIS. WITH THE CONTINUED COLD ADVECTION AND MIX OF LOW AND MID CLOUD...TEMPS WILL STRUGGLE TO GET TO FREEZING IN MANY SPOTS. NAM IS STILL HINTING AT SOME LAKE EFFECT FLURRIES OR LIGHT SNOW SHOWERS THOUGH LAKE EFFECT PARAMETERS DURING THE DAY ARE NOT SUPER IMPRESSIVE. KMD && .LONG TERM... 236 AM CST MONDAY NIGHT THROUGH SATURDAY... MONDAY NIGHT...A MORE SIGNIFICANT SURGE OF COLD AIR COMES STREAMING IN. THIS WILL ENHANCE LAKE EFFECT PARAMETERS...ESPECIALLY IN NORTHWEST INDIANA AND PORTIONS OF SOUTHERN COOK COUNTY. EQUILIBRIUM LEVELS ARE NOT MUCH BETTER THAN DURING THE DAY MONDAY...BUT LOW LEVEL LAPSE RATES/LAKE INDUCED CAPE ARE SLIGHTLY BETTER TO SUPPORT SOME LIGHT ACCUMULATIONS...ESPECIALLY AFTER MIDNIGHT IN NW INDIANA. AS THE ARCTIC HIGH CONTINUES SOUTH INTO THE PLAINS...WINDS WILL BACK TO NW AND PUSH LAKE EFFECT SNOWS EASTWARD. 850 TEMPS IN THE MINUS TEENS SUPPORT HIGHS ONLY IN THE UPPER TEENS TO LOW 20S IN SPITE OF SOME CLEARING THROUGH THE DAY. TUESDAY NIGHT/WEDNESDAY MORNING FEATURE THE COLDEST AIR MASS. NW FLOW PERSISTS WITH MIGRATORY SHORTWAVE ENERGY. WINDS WILL BACK TO THE WSW THROUGH THE DAY. GIVEN THE COLD START...EXPECT HIGHS SIMILAR TO TUESDAY AND POSSIBLY A BIT COOLER WITH 20 BEING A STRETCH IN PLACES. BY THURSDAY THE UPPER FLOW PATTERN WILL MODIFY AS THE DEEP COLD TROUGH EXTENDING FROM NORTHERN ONTARIO BACK SOUTHWEST TO THE PACIFIC GETS PINCHED OFF IN THE NORTH AND SHIFTS EAST OUR FOCUS THEN SHIFTS TO A CUT OFF LOW OVER CALIFORNIA. SOUTHERLY FLOW AHEAD OF THIS SYSTEM WILL TRANSPORT SOME SLIGHTLY WARMER AIR ALONG WITH ADDITIONAL GULF MOISTURE. MEANWHILE...THE SHORTWAVE ENERGY WILL CONTINUE TO ROTATE SOUTH AND WEST AROUND THE ARCTIC VORTEX THAT AT THIS POINT SETS UP NORTH OF HUDSON BAY. THE CALI LOW WILL EVENTUALLY EJECT EAST AND NORTH FRIDAY INTO SATURDAY. THE CLASH OF THE WARMER GULF AIR AND ARCTIC AIR ENTRENCHED OVER THE REGION LOOKS TO RESULT IN A DYNAMIC WINTER STORM SYSTEM. PRECIP TYPE WILL BE AN ISSUE SOMEWHERE IN THE REGION AHEAD OF THE LOW...WITH AN IMPRESSIVE DEFORMATION SNOW BAND EXPECTING TO SET UP BEHIND IT DUE TO A REPLENISHMENT OF COLD AIR AND STRONG BAROCLINIC ZONE. A LOT HINGES ON THE INTERACTION WITH THE NORTHERN STREAM AS TO WHERE THIS SYSTEM HEADS...BUT MODELS TO THIS POINT HAVE BEEN SOMEWHAT CONSISTENT ON THE TIME FRAME OF CONCERN BEING LATER FRIDAY AND ESPECIALLY INTO SATURDAY WITH SOME WINTRY PRECIPITATION SOMEWHERE IN OUR AREA. COLD AIR COMES RIGHT BACK IN BEHIND IT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * LAKE EFFECT CLOUDS/FLURRIES POSSIBLE MONDAY MORNING. JEE //DISCUSSION...UPDATED 12Z... VFR WITH LIGHT WINDS THROUGH TONIGHT. SUBTLE FRONT MOVES ACROSS AREA LATE TONIGHT AND ALLOWS WINDS TO TURN IN OFF THE LAKE WHICH SHOULD BRING SOME MVFR CIGS AND PROBABLY SOME FLURRIES INTO NE ILLINOIS MONDAY MORNING. IZZI //ORD AND MDW CONFIDENCE...UPDATED 14Z... * LOW-MEDIUM CONFIDENCE IN LAKE EFFECT CLOUDS/FLURRIES. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR CIGS/LAKE EFFECT SNOW SHOWERS POSSIBLE. TUESDAY THROUGH FRIDAY...SLIGHT CHANCE OF MVFR CIGS AT TIMES OTHERWISE VFR. FRIDAY NIGHT AND SATURDAY...CHANCE OF SNOW AND IFR. IZZI && .MARINE... 150 AM CST MODERATE NORTHWEST WINDS WILL EASE SOME TODAY AND THEN VEER MORE NORTHERLY TONIGHT INTO MONDAY. NORTHERLY WINDS WILL FRESHEN UP MONDAY NIGHT INTO TUESDAY AS ARCTIC AIR SPILLS INTO THE REGION. WINDS WILL BACK TO SOUTHWEST AND INCREASE FURTHER TO GALES WEDNESDAY AND CONTINUE THROUGH THURSDAY MORNING AND STRONG LOW PRESSURE MOVES SOUTH INTO HUDSON BAY TIGHTENING UP THE PRESSURE GRADIENT WITH ARCTIC AIR FIRMLY ENTRENCHED OVER THE AREA. WINDS LOOK TO SUBSIDE LATER THURSDAY INTO EARLY FRIDAY BEFORE POTENTIALLY RAMPING UP AGAIN NEXT WEEKEND AS ANOTHER STORM SYSTEM POTENTIALLY APPROACHES THE REGION THOUGH SIGNIFICANT MODEL DIFFERENCES EXIST IN TRACK AND INTENSITY OF THAT SYSTEM. IZZI && .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 NATIONAL WEATHER SERVICE LINCOLN IL 532 AM CST Sun Dec 28 2014 .SHORT TERM...(Today) ISSUED AT 305 AM CST SUN DEC 28 2014 Main short-term challenge will be timing of the clearing trend today. 08z/2am IR satellite imagery shows low clouds covering much of central Illinois, except across the far northern KILX CWA from Peoria northward where clouds have eroded. The 06z NAM 1000-850mb RH field has a good handle on the current cloud cover, so have generally followed its solution for sky cover today. End result will be clearing skies along the I-74 corridor by mid to late morning, with clouds lingering into the afternoon further south. Skies will become mostly clear across the board by late afternoon as high pressure builds in from the west. High temperatures will be near normal for this time of year in the middle to upper 30s. && .LONG TERM...(Tonight through Saturday) ISSUED AT 305 AM CST SUN DEC 28 2014 Quiet weather is expected for the next several days before a storm system gradually approaches from the southwest by the end of the week. High pressure will control the weather across central Illinois on Monday, resulting in cool/dry conditions with highs in the 30s. Meanwhile, a significant chunk of cold air currently in place across central/western Canada will sink southward into the central CONUS by the middle of the week. Models have been hinting at some light snow/flurries as CAA increases Monday night into Tuesday, with the NAM being more aggressive with potential QPF. NAM time-height cross-sections reveal stronger lift within a deeper moist layer than the GFS indicates. Think the low-level moisture may be a bit overdone on the NAM, so am leaning toward the GFS solution here. Even with drier air below 850mb, think lift will be strong enough to warrant mention of a few flurries Monday night and perhaps even into Tuesday morning before moisture profile thins and high pressure builds into the region. Heart of the cold airmass will arrive Tuesday night into Wednesday, when overnight lows dip into the single digits and teens and highs only reach the lower to middle 20s. Once high slowly begins to shift eastward, attention turns to a developing southern-stream storm system associated with a cut-off upper low over the Desert Southwest. Models are still displaying a typical spread of solutions that far out, but confidence is growing that a precipitation event will impact central Illinois by the end of the week. Both the GFS and ECMWF show surface low pressure developing over the Texas panhandle by Friday evening, then lifting northeastward into the Great Lakes on Saturday. While their tracks are not in perfect agreement, a N/NW trend is becoming apparent. GFS takes the low west of the CWA to near Moline by 12z Sat, while the ECMWF tracks the low to near Champaign. Both tracks are further N/NW than previous runs, which suggests precip may be more in the form of rain or a rain/snow mix across the area than previously thought. Based on GFS forecast soundings, if precip is able to spread northward into the initially cold/dry airmass Friday morning, light snow will be the primary precip type. As temps warm into the middle to upper 30s, the snow will likely mix with rain across much of the area by Friday afternoon. Precip will likely remain quite light during the day Friday, with widespread precip holding off until Friday night when airmass saturates and stronger lift arrives. At this point, will carry rain along/south of I-70...a rain/snow mix across the middle of the CWA...and snow along/north of a Rushville to Bloomington line Friday night into Saturday. The track of the system will likely change with successive model runs, so precip type and any potential snow accumulations still remain uncertain. && .AVIATION...(For the 12Z TAFS through 12Z Monday morning) ISSUED AT 532 AM CST SUN DEC 28 2014 Main concern across the central Illinois terminals through the 12Z TAF valid time regards the disposition of the MVFR CIGS today as high pressure builds into the area. Once the low clouds clear out, VFR conditions will prevail through the remainder of the period. The low cloud clearing trends today are tough to pinpoint as the back edge of the cloud deck is far from smooth. Actually, the back edge of the cloud deck is ragged, which should allow for skies to go back/forth between BKN/OVC and SCT for a few hours before finally clearing. The recent progression of the low clouds has become difficult to track on satellite imagery due to a cirrus shield moving over top of the low clouds. However, as best as I can tell, the HRRR has a pretty good handle on the trends, and will lean on it for clearing trends this morning into early afternoon. Northwest winds will continue to diminish in speed as a weak area of high pressure approaches today, eventually leading to light/variable winds tonight. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Bak
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
514 AM CST SUN DEC 28 2014 .SHORT TERM... 236 AM CST THROUGH MONDAY... HIGH PRESSURE NOSING IN FROM THE WEST RESULTING IN GRADUAL CLEARING FROM WEST TO EAST EARLY THIS MORNING WITH THE BACK EDGE ALREADY THOROUGH ROCKFORD. ONCE THE LOW CLOUDS CLEAR EXPECT SOME PASSING HIGH CLOUDS THIS MORNING EMANATING FROM A MODEST UPPER LOW IN TEXAS...OTHERWISE IT WILL BE A SEASONAL MOSTLY SUNNY DAY WITH HIGHS TOPPING OUT IN THE LOW 30S OR SO. WE`LL HOLD A WEST WIND WHICH WILL MAKE IT FEEL A LITTLE COOLER...THOUGH TODAY LOOKS TO BE THE WARMEST FOR THE REST OF 2014. ARCTIC HIGH PRESSURE CONTINUES TO SINK INTO THE CENTER OF THE COUNTRY TONIGHT. LOCALLY...OUR WINDS TURN NORTHERLY ALLOWING SOME OF THIS CONTINUE MOVING IN. ZONAL FLOW ALOFT WILL KEEP SOME HIGHER CLOUDS PUSHING INTO THE REGION PREVENTING A REAL COLD NIGHT...BUT STILL THE COLDEST WE`VE SEEN IN A WHILE WITH LOWS INTO THE 20S. BY MONDAY MORNING...A BACKDOOR FRONT MOVING DOWN THE LAKE WILL CONTINUE THE STREAM OF COLDER AIR. ADDITIONALLY LAKE EFFECT CLOUDS WILL MOVE INTO NORTHWEST INDIANA AND PORTIONS OF NORTHEAST ILLINOIS. WITH THE CONTINUED COLD ADVECTION AND MIX OF LOW AND MID CLOUD...TEMPS WILL STRUGGLE TO GET TO FREEZING IN MANY SPOTS. NAM IS STILL HINTING AT SOME LAKE EFFECT FLURRIES OR LIGHT SNOW SHOWERS THOUGH LAKE EFFECT PARAMETERS DURING THE DAY ARE NOT SUPER IMPRESSIVE. KMD && .LONG TERM... 236 AM CST MONDAY NIGHT THROUGH SATURDAY... MONDAY NIGHT...A MORE SIGNIFICANT SURGE OF COLD AIR COMES STREAMING IN. THIS WILL ENHANCE LAKE EFFECT PARAMETERS...ESPECIALLY IN NORTHWEST INDIANA AND PORTIONS OF SOUTHERN COOK COUNTY. EQUILIBRIUM LEVELS ARE NOT MUCH BETTER THAN DURING THE DAY MONDAY...BUT LOW LEVEL LAPSE RATES/LAKE INDUCED CAPE ARE SLIGHTLY BETTER TO SUPPORT SOME LIGHT ACCUMULATIONS...ESPECIALLY AFTER MIDNIGHT IN NW INDIANA. AS THE ARCTIC HIGH CONTINUES SOUTH INTO THE PLAINS...WINDS WILL BACK TO NW AND PUSH LAKE EFFECT SNOWS EASTWARD. 850 TEMPS IN THE MINUS TEENS SUPPORT HIGHS ONLY IN THE UPPER TEENS TO LOW 20S IN SPITE OF SOME CLEARING THROUGH THE DAY. TUESDAY NIGHT/WEDNESDAY MORNING FEATURE THE COLDEST AIR MASS. NW FLOW PERSISTS WITH MIGRATORY SHORTWAVE ENERGY. WINDS WILL BACK TO THE WSW THROUGH THE DAY. GIVEN THE COLD START...EXPECT HIGHS SIMILAR TO TUESDAY AND POSSIBLY A BIT COOLER WITH 20 BEING A STRETCH IN PLACES. BY THURSDAY THE UPPER FLOW PATTERN WILL MODIFY AS THE DEEP COLD TROUGH EXTENDING FROM NORTHERN ONTARIO BACK SOUTHWEST TO THE PACIFIC GETS PINCHED OFF IN THE NORTH AND SHIFTS EAST OUR FOCUS THEN SHIFTS TO A CUT OFF LOW OVER CALIFORNIA. SOUTHERLY FLOW AHEAD OF THIS SYSTEM WILL TRANSPORT SOME SLIGHTLY WARMER AIR ALONG WITH ADDITIONAL GULF MOISTURE. MEANWHILE...THE SHORTWAVE ENERGY WILL CONTINUE TO ROTATE SOUTH AND WEST AROUND THE ARCTIC VORTEX THAT AT THIS POINT SETS UP NORTH OF HUDSON BAY. THE CALI LOW WILL EVENTUALLY EJECT EAST AND NORTH FRIDAY INTO SATURDAY. THE CLASH OF THE WARMER GULF AIR AND ARCTIC AIR ENTRENCHED OVER THE REGION LOOKS TO RESULT IN A DYNAMIC WINTER STORM SYSTEM. PRECIP TYPE WILL BE AN ISSUE SOMEWHERE IN THE REGION AHEAD OF THE LOW...WITH AN IMPRESSIVE DEFORMATION SNOW BAND EXPECTING TO SET UP BEHIND IT DUE TO A REPLENISHMENT OF COLD AIR AND STRONG BAROCLINIC ZONE. A LOT HINGES ON THE INTERACTION WITH THE NORTHERN STREAM AS TO WHERE THIS SYSTEM HEADS...BUT MODELS TO THIS POINT HAVE BEEN SOMEWHAT CONSISTENT ON THE TIME FRAME OF CONCERN BEING LATER FRIDAY AND ESPECIALLY INTO SATURDAY WITH SOME WINTRY PRECIPITATION SOMEWHERE IN OUR AREA. COLD AIR COMES RIGHT BACK IN BEHIND IT. KMD && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * LAKE EFFECT CLOUDS/FLURRIES POSSIBLE MONDAY MORNING IZZI //DISCUSSION...UPDATED 12Z... VFR WITH LIGHT WINDS THROUGH TONIGHT. SUBTLE FRONT MOVES ACROSS AREA LATE TONIGHT AND ALLOWS WINDS TO TURN IN OFF THE LAKE WHICH SHOULD BRING SOME MVFR CIGS AND PROBABLY SOME FLURRIES INTO NE ILLINOIS MONDAY MORNING. IZZI //ORD AND MDW CONFIDENCE...UPDATED 12Z... * LOW-MEDIUM CONFIDENCE IN LAKE EFFECT CLOUDS/FLURRIES * HIGH CONFIDENCE IN EVERYTHING ELSE IZZI //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR CIGS/LAKE EFFECT SNOW SHOWERS POSSIBLE. TUESDAY THROUGH FRIDAY...SLIGHT CHANCE OF MVFR CIGS AT TIMES OTHERWISE VFR. FRIDAY NIGHT AND SATURDAY...CHANCE OF SNOW AND IFR. IZZI && .MARINE... 150 AM CST MODERATE NORTHWEST WINDS WILL EASE SOME TODAY AND THEN VEER MORE NORTHERLY TONIGHT INTO MONDAY. NORTHERLY WINDS WILL FRESHEN UP MONDAY NIGHT INTO TUESDAY AS ARCTIC AIR SPILLS INTO THE REGION. WINDS WILL BACK TO SOUTHWEST AND INCREASE FURTHER TO GALES WEDNESDAY AND CONTINUE THROUGH THURSDAY MORNING AND STRONG LOW PRESSURE MOVES SOUTH INTO HUDSON BAY TIGHTENING UP THE PRESSURE GRADIENT WITH ARCTIC AIR FIRMLY ENTRENCHED OVER THE AREA. WINDS LOOK TO SUBSIDE LATER THURSDAY INTO EARLY FRIDAY BEFORE POTENTIALLY RAMPING UP AGAIN NEXT WEEKEND AS ANOTHER STORM SYSTEM POTENTIALLY APPROACHES THE REGION THOUGH SIGNIFICANT MODEL DIFFERENCES EXIST IN TRACK AND INTENSITY OF THAT SYSTEM. IZZI && .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 NATIONAL WEATHER SERVICE LINCOLN IL 305 AM CST Sun Dec 28 2014 .SHORT TERM...(Today) ISSUED AT 305 AM CST SUN DEC 28 2014 Main short-term challenge will be timing of the clearing trend today. 08z/2am IR satellite imagery shows low clouds covering much of central Illinois, except across the far northern KILX CWA from Peoria northward where clouds have eroded. The 06z NAM 1000-850mb RH field has a good handle on the current cloud cover, so have generally followed its solution for sky cover today. End result will be clearing skies along the I-74 corridor by mid to late morning, with clouds lingering into the afternoon further south. Skies will become mostly clear across the board by late afternoon as high pressure builds in from the west. High temperatures will be near normal for this time of year in the middle to upper 30s. && .LONG TERM...(Tonight through Saturday) ISSUED AT 305 AM CST SUN DEC 28 2014 Quiet weather is expected for the next several days before a storm system gradually approaches from the southwest by the end of the week. High pressure will control the weather across central Illinois on Monday, resulting in cool/dry conditions with highs in the 30s. Meanwhile, a significant chunk of cold air currently in place across central/western Canada will sink southward into the central CONUS by the middle of the week. Models have been hinting at some light snow/flurries as CAA increases Monday night into Tuesday, with the NAM being more aggressive with potential QPF. NAM time-height cross-sections reveal stronger lift within a deeper moist layer than the GFS indicates. Think the low-level moisture may be a bit overdone on the NAM, so am leaning toward the GFS solution here. Even with drier air below 850mb, think lift will be strong enough to warrant mention of a few flurries Monday night and perhaps even into Tuesday morning before moisture profile thins and high pressure builds into the region. Heart of the cold airmass will arrive Tuesday night into Wednesday, when overnight lows dip into the single digits and teens and highs only reach the lower to middle 20s. Once high slowly begins to shift eastward, attention turns to a developing southern-stream storm system associated with a cut-off upper low over the Desert Southwest. Models are still displaying a typical spread of solutions that far out, but confidence is growing that a precipitation event will impact central Illinois by the end of the week. Both the GFS and ECMWF show surface low pressure developing over the Texas panhandle by Friday evening, then lifting northeastward into the Great Lakes on Saturday. While their tracks are not in perfect agreement, a N/NW trend is becoming apparent. GFS takes the low west of the CWA to near Moline by 12z Sat, while the ECMWF tracks the low to near Champaign. Both tracks are further N/NW than previous runs, which suggests precip may be more in the form of rain or a rain/snow mix across the area than previously thought. Based on GFS forecast soundings, if precip is able to spread northward into the initially cold/dry airmass Friday morning, light snow will be the primary precip type. As temps warm into the middle to upper 30s, the snow will likely mix with rain across much of the area by Friday afternoon. Precip will likely remain quite light during the day Friday, with widespread precip holding off until Friday night when airmass saturates and stronger lift arrives. At this point, will carry rain along/south of I-70...a rain/snow mix across the middle of the CWA...and snow along/north of a Rushville to Bloomington line Friday night into Saturday. The track of the system will likely change with successive model runs, so precip type and any potential snow accumulations still remain uncertain. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) ISSUED AT 1142 PM CST SAT DEC 27 2014 Precip has shifted east of all the terminal sites, and MVFR clouds will blanket the area the rest of the night and through much of the morning tomorrow. CMI has a brief break in the MVFR clouds until 07z/1am, but low clouds will fill in by 07z. The back edge of the clouds is positioned to our west from south-central Wisconsin through SE Iowa and down through the middle of Missouri. The clearing progression has slowed later this evening, and that trend should allow low clouds to linger over the terminal sites into tomorrow morning. PIA should be the first to clear out, possibly as early as 12-13z. Clearing trends should speed up with turbulent mixing of dry air tomorrow, reaching BMI by 14z, SPI by 16z, CMI by 18z and DEC by 19z. The HRRR is quicker with clearing, as is the RAP. Will stick with a more pessimistic clearing trend until satellite images give more confidence in the models cloud progressions. Wind speeds will decrease below 10kt by 08z-09z tonight, and remain less than 10kt through the day tomorrow. Wind direction will start out NW, then back to the west during the day as high pressure builds farther into Illinois. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
150 AM CST SUN DEC 28 2014 .SHORT TERM... 307 PM CST REMAINDER OF THIS AFTERNOON AND TONIGHT... A STRONG COLD FRONT IS TRACKING ACROSS THE REGION...USHERING IN MUCH COOLER AIR ALONG WITH SOME SCT LIGHT PCPN. AS OF 230PM CDT...THE SFC FRONTAL BOUNDARY EXTENDED FROM WESTERN LOWER MICHIGAN...TO EAST-CENTRAL IL...TO SERN MO. WINDS HAVE BEEN GUSTING TO ARND 30 MPH FOLLOWING THE FROPA WHILE VEERING FROM SWLY TO WLY. TEMPERATURES ARE SLOWLY DROPPING OFF WITH THE FROPA AND THE BULK OF THE PCPN IS POST-FRONTAL AS A STRONG LOW LEVEL JET HAS SET UP ALONG AN ELEVATED BAROCLINIC ZONE. SOME SCT RAIN IS STILL POSSIBLE OVER NWRN IN AND ECNTRL IL AHEAD OF THE FRONT...BUT AS COOLER AIR FILTERS IN BEHIND THE BOUNDARY...LIQUID PCPN IN THE POST-SFC FRONTAL BOUNDARY SHOULD TRANSITION INTO A MIX OF RAIN...SNOW AND POSSIBLE SOME GRAPPLE. THE SHARPER TEMPERATURE DROPOFF WILL OCCUR LATER THIS AFTERNOON AND THROUGH THIS EVENING AS A SECONDARY TROUGH ASSOCIATED WITH A SURGE OF COOLER AIR PUSHED ACROSS THE EVENING WHICH WILL BE ACCOMPANIED BY A WIND SHIFT TO WLY-WNWLY. ANY LINGERING PCPN SHOULD PUSH END OVER NWRN IL-ECNTRL IL DURG THE LATE EVENING HOURS AND TEMPERATURES OVERNIGHT SHOULD RANGE FROM ARND 20F OVER THE ROCKFORD AREA TO THE UPPER 20S EAST OF THE I-55 CORRIDOR. KREIN && .LONG TERM... 307 PM CST SUNDAY THROUGH SATURDAY... THE PASSAGE OF THE SYSTEM CURRENTLY MOVING THROUGH THE REGION IS A SIGNAL OF A MAJOR PATTERN SHIFT FROM THE UNSEASONABLY WARM CONDITIONS OF RECENT DAYS BACK TO MORE SEASONABLE CONDITIONS AS THE SHORT-WAVELENGTH...HIGH AMPLITUDE TROUGH SHEARS OUT INTO BROAD WEAK TROUGHING ALOFT THROUGH THE REMAINDER OF THE WEEKEND. THE GENERAL TEMPERATURE TREND FOR SUNDAY AND INTO EARLY NEXT WEEK WILL BE FOR A SLOW COOLING TREND UNDER BROAD...WEAK HEIGHT FALLS ALOFT. A STRONGER SURGE OF COLD AIR WITH A SERIES OF NRN STREAM SHORTWAVES WILL USHER IN THE TRUE COLD AIR BY MONDAY NIGHT AND TUESDAY WITH TEMPERATURES MONDAY MORNING DROPPING OFF INTO THE LOWER TEENS OVER THE ROCKFORD AREA TO AROUND 20F EAST OF THE I-55 CORRIDOR. THE UPPER LEVEL PATTERN WILL SET UP TO MORE ZONAL OVER THE SRN CONUS AS THE MAIN JET PATTERN SHIFTS TO THE SOUTH WHILE POLAR-SOURCED SHORT WAVE ENERGY DROPS INTO THE UPPER MISSISSIPPI VALLEY AND THROUGH THE MIDWEST AND GREAT LAKES REGIONS THROUGH THE REMAINDER OF NEXT WEEK. THE LARGE SCALE PATTERN WILL ALSO BECOME LESS PROGRESSIVE...WITH THE LONGER RANGE GUIDANCE INDICATING A CUT OFF LOW DIGGING INTO SRN CALIFORNIA AND VERY SLOWLY TRACKING EWD THROUGH THE DESERT SOUTHWEST BY LATE NEXT WEEK WHILE SUB-TROPICAL HIGH PRESSURE REMAINS PARKED OVER THE WESTERN CARIBBEAN AND GREATER ANTILLES. THE SLOWING PROGRESSION TO THE LONGWAVE PATTERN WILL IN TURN SET UP A PERIOD WITH A SERIES OF NRN STREAM SHORTWAVES KEEPING A STEADY STREAM OF SEASONABLY COLD AIR INTO THE REGION. THE NEXT CHANCE FOR ANY PCPN ACROSS THE AREA WILL BE MONDAY AFTERNOON INTO TUESDAY AS A COLD FRONT ON THE LEADING EDGE OF AN ARCTIC AIRMASS TRIES TO SQUEEZE OUT A LITTLE SNOW IN A RELATIVELY DRY ENVIRONMENT. LITTLE OR NO ACCUMULATION IS EXPECTED OVER MUCH OF THE AREA... PERHAPS A DUSTING WITH SCT SNOW SHOWERS. HOWEVER...AS SFC HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO THE GREAT LAKES REGIONS...A PERIOD OF GENERALLY NORTHERLY FLOW WILL SET UP OVER LAKE MICHIGAN...AND THERE WILL BE A CHANCE FOR SOME LAKE EFFECT SNOW INITIALLY ALONG THE ILLINOIS LAKE MICHIGAN SHORE MONDAY EVENING AND THEN GRADUALLY TRANSITIONING TO THE EAST OVER NWRN INDIANA MONDAY NIGHT INTO TUESDAY MORNING AS FLOW BACKS MORE NWLY. IT IS STILL A LITTLE EARLY TO DISCUSS ACCUMULATIONS WITH LAKE EFFECT SNOW AT THIS POINT...BUT HAVE INCREASED POPS TO LIKELY FOR THE FAVORED LAKE EFFECT AREAS AND WOULD ANTICIPATE SOME MEASURABLE ACCUMULATION. MIDWEEK SHOULD BE DRY...BUT WITH THE LOWEST TEMPERATURES OF THE PERIOD AS THE SFC HIGH PRESSURE SETTLES INTO THE LOWER MISSISSIPPI VALLEY AND SERN CONUS. BY LATE NEXT WEEK...THE LONGER RANGE GUIDANCE IS INDICATING THAT THE CUT OFF LOW DROPPING INTO THE DESERT SOUTHWEST WILL FINALLY BEGIN TO LIFT OUT TO THE NORTHEAST WHILE A NRN STREAM SHORTWAVE DROPS THROUGH THE NRN PLAINS TO THE UPPER MISSISSIPPI VALLEY. HOWEVER...WHILE THE LONGER RANGE GUIDANCE IS IN RELATIVELY DECENT AGREEMENT ON THE TREND...THERE ARE CONSIDERABLE DIFFERENCES IN THE TIMING WITH THE GFS MUCH FASTER THAN THE ECMWF OR GEM. GIVEN THAT SOUTHWEST CUT-OFF LOWS TEND TO LINGER LONGER THAN THE MODELS LIKE TO FORECAST...HAVE TRENDED THE LONGER TERM FORECAST CLOSER TO THE SLOWER SOLUTIONS...AND WOULD NOT BE SURPRISED TO SEE THE MODELS TREND EVEN SLOWER THAN CURRENTLY INDICATED. SO...WILL LIMIT POPS TO CHANCE LEVELS WITH TEMPERATURES CONDUCIVE TO SNOW FOR NOW. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * MVFR CIGS CLEAR OUT PRIOR TO SUNRISE IZZI //DISCUSSION...UPDATED 06Z... BACK EDGE OF THE STRATUS UPSTREAM OVER NW IL AND SW WI WILL CONTINUE STEADY SOUTHEAST PROGRESS OVERNIGHT WITH CONDITIONS EXPECTED TO GO VFR PRIOR TO SUNRISE AT ALL TERMINALS. OTHERWISE LOOK FOR LIGHT WINDS AND CLEAR SKIES REMAINDER OF TAF CYCLE. IZZI //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE ON PRECISE TIMING OF CLEARING * HIGH CONFIDENCE IN EVERYTHING ELSE IZZI //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...CHC SNOW LATE. TUESDAY THROUGH THURSDAY...PRIMARILY VFR. FRIDAY...CHC SNOW. MVFR/IFR PSBL. BMD && .MARINE... 150 AM CST MODERATE NORTHWEST WINDS WILL EASE SOME TODAY AND THEN VEER MORE NORTHERLY TOONIGHT INTO MONDAY. NORTHERLY WINDS WILL FRESHEN UP MONDAY NIGHT INTO TUESDAY AS ARCTIC AIR SPILLS INTO THE REGION. WINDS WILL BACK TO SOUTHWEST AND INCREASE FURTHER TO GALES WEDNESDAY AND CONTINUE THROUGH THURSDAY MORNING AND STRONG LOW PRESSURE MOVES SOUTH INTO HUDSON BAY TIGHTENING UP THE PRESSURE GRADIENT WITH ARCTIC AIR FIRMLY ENTRENTCHED OVER THE AREA. WINDS LOOK TO SUBSIDE LATER THURSDAY INTO EARLY FRIDAY BEFORE POTENTIALLY RAMPING UP AGAIN NEXT WEEKEND AS ANOTHER STORM SYSTEM POTENTIALLY APPROACHES THE REGION THOUGH SIGNIFICANT MODEL DIFFERENCES EXIST IN TRACK AND INTENSITY OF THAT SYSTEM. IZZI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY. && $$ 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 NATIONAL WEATHER SERVICE LINCOLN IL 1142 PM CST Sat Dec 27 2014 .UPDATE... ISSUED AT 900 PM CST SAT DEC 27 2014 The cold air aloft driving into the north side of the system has been changing the rain over to snow and sleet for a couple of hours at the end of precipitation. There seems to be less evidence of the snow/sleet band in the observations and reports over the last hour or so, but the air temps are dropping toward freezing in the back edge of the precip, so will continue to indicate a band of snow/sleet at the western edge of precip until precip comes to an end later tonight. Any light snow/sleet accumulation would create slippery roads. Road temps have generally been reporting above freezing, but some bridges, overpasses, and secondary roads would be more susceptible to icing. The precip is increasing its forward progress toward Indiana, and we have adjusted the weather grids to end precip a few hours sooner tonight. All precip will likely be out of our counties by 1 am and possibly midnight. Gusty northwest winds will develop after precip ends, ushering the colder air. Some clearing is forecast for our NW counties later tonight, which would allow low temps to drop off a bit farther than guidance. Will trim a couple degrees off lows toward Galesburg/Lacon. Updated forecast grids and info will be available shortly. && .SHORT TERM...(Tonight) ISSUED AT 313 PM CST SAT DEC 27 2014 Low clouds, drizzle, light rain showers still ongoing across the forecast area this afternoon. Cold front about out of ILX area...just NW of Lawrenceville. Some flakes mixing into the precip on the extreme NW edge of the post frontal echos on radar. Front progression somewhat steady although running into more parallel flow aloft. Cold dense air from the NW really colder behind the post frontal precip spread across the radar mosaic. Timing of the cold air a minor concern as time progresses. Ground temps still close to 40 degrees, but with the arrival of the freezing temps, some elevated surfaces could develop some slick spots. The arrival of the coldest air will be after the precip has come to an end...so freezing should be confined to the residual moisture/puddles from today`s drizzle/rain. Another issue with the overnight forecast is the cloud cover. GFS is quick to break it out...a little faster than is currently represented on sat imagery. NAM is far cloudier, trapping the moisture in the boundary layer and preventing the mix out entirely. RUC looking more like the NAM with representing the developing inversion behind the boundary. Plenty of dry air up there, but how quickly it will erode through the clouds is a huge question mark. Covered in cirrus all day, not convinced the diurnal influence on the clouds is enough to erode them at sunset. Considering how quickly sunset is approaching, going to split the difference more or less with a slower clearing out...but not quite as trapped as the NAM. Some breaking up could be seen in the far NW, and forecast low temps are considerably cooler as a result. However, going cloudier overall through the night. && .LONG TERM...(Sunday through Saturday) ISSUED AT 313 PM CST SAT DEC 27 2014 High pressure behind the front will bring dry weather to the area for tomorrow through Monday. However, this mild high pressure area will be temporary as a stronger/colder high pressure area drops into the region Tuesday. A weak boundary will be between these two high pressure areas, but it will have very little moisture to work with. This will be an Arctic front with much colder air behind it. Any precip with this Arctic front will be very light and could occur Monday night. With the colder temps and limited moisture, only pcpn expected will be flurries. Also believe this will be across the northern 2/3rds of the CWA, leaving the southeastern CWA dry as the area flurries moves east. Temps will be around normal tomorrow and Monday, but then drop to below normal for Tue as the Arctic cold high pressure moves in. Cold, dry Arctic high pressure will dominate the area for days 3-5, but as the high pressure modifies and moves into southeastern US, temps will begin to warm gradually and a weather system will develop in the southwestern US and begin to move out into the plains. With high pressure to the east and a surface low pressure area to the west, warmer air will not be the only thing to return to the area. Moisture will also return and this will bring pcpn to the area as the moisture interacts with a warm front and lifts northward into the area. P-type could be very interesting and be dependent on the surface temperature and temps in the lower levels. Models forecasting temps above zero at 850mb over the area, which would indicate rain. However, surface temps look to be below freezing Fri night; and this could mean frozen pcpn possible. Considering Fri through Sat is Day6-7, will not get too detailed on pcpn type and just go with snow or rain, or a mix of rain and snow. Thinking mostly rain on Friday with a mix in the north, then a mix becoming all snow on Fri night, and then all snow in the east on Sat. Am expecting the p-type to change over the next several days, and when the event becomes better defined by the models and closer. As mentioned earlier, temps will start cold and then gradually warm during the week. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) ISSUED AT 1142 PM CST SAT DEC 27 2014 Precip has shifted east of all the terminal sites, and MVFR clouds will blanket the area the rest of the night and through much of the morning tomorrow. CMI has a brief break in the MVFR clouds until 07z/1am, but low clouds will fill in by 07z. The back edge of the clouds is positioned to our west from south-central Wisconsin through SE Iowa and down through the middle of Missouri. The clearing progression has slowed later this evening, and that trend should allow low clouds to linger over the terminal sites into tomorrow morning. PIA should be the first to clear out, possibly as early as 12-13z. Clearing trends should speed up with turbulent mixing of dry air tomorrow, reaching BMI by 14z, SPI by 16z, CMI by 18z and DEC by 19z. The HRRR is quicker with clearing, as is the RAP. Will stick with a more pessimistic clearing trend until satellite images give more confidence in the models cloud progressions. Wind speeds will decrease below 10kt by 08z-09z tonight, and remain less than 10kt through the day tomorrow. Wind direction will start out NW, then back to the west during the day as high pressure builds farther into Illinois. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SHORT TERM...HJS LONG TERM...Auten AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1216 PM EST SUN DEC 28 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 335 AM EST SUN DEC 28 2014 A COLD FRONT ACROSS OHIO AND NORTHWEST KENTUCKY WILL CONTINUE MOVING SOUTHEAST. THIS WILL BE FOLLOWED BY A RIDGE OF HIGH PRESSURE WHICH WILL MOVE SUNDAY NIGHT AND MONDAY. A DRY SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY FRIDAY AND ACROSS OUR REGION SATURDAY. && .NEAR TERM /TODAY AND TONIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 RADAR SHOWS PRECIPITATION WAS ENDING RAPIDLY FROM THE NORTHWEST AND WILL PRETTY MUCH BE DONE BY FORECAST RELEASE TIME. SOME SITES ACROSS OUR SOUTH AND SOUTHEAST MAY SEE A LITTLE DRIZZLE PRIOR TO 7AM. MAIN ISSUES TODAY WILL BE HOW LONG CLOUDS WILL REMAIN AND TEMPERATURES. SATELLITE SHOWS CLEARING LINE ACROSS NORTHWEST ILLINOIS. ALTHOUGH THERE HAVE BEEN A FEW HOLES FARTHER SOUTHEAST. THE RAP MODEL SOUNDINGS INDICATE MOSTLY CLOUDY SKIES THIS MORNING AND DECREASING CLOUDS FROM MIDDAY ON. EXPECT CLOUDS TO PERSIST OVER SOUTHERN SECTIONS MOST OF TODAY AS THIS WILL BE LAST AREA TO CLEAR OUT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE MIDDLE 30S NORTH TO AROUND 40 FAR SOUTH WHICH IS SLIGHTLY BELOW A MOS BLEND ON TEMPERATURES. TONIGHT WILL BECOME MOSTLY CLEAR AS WEAK RIDGE OF HIGH PRESSURE MOVES INTO OUR REGION. WENT CLOSE TO A MOS BLEND ON TEMPERATURES WITH LOWS IN THE LOWER 20S OVER NORTHERN SECTIONS AND THE MIDDLE AND UPPER 20S SOUTH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 MONDAY WILL BE SEASONABLY COOL WITH WEAK COLD ADVECTION AND HIGH PRESSURE BUILDING IN FROM THE NORTHWEST. LOW LEVEL THICKNESS INDICATE HIGHS SHOULD BE FROM THE MIDDLE 30S OVER NORTHERN SECTIONS TO AROUND 40 FAR SOUTH WITH MOSTLY SUNNY SKIES. MODELS INDICATE A WEAK UPPER DISTURBANCE WILL TRACK ACROSS INDIANA LATE MONDAY NIGHT AS A SECONDARY ARCTIC COLD FRONT MOVES OUR WAY. THE NAM SHOWS SOME QPF ACROSS OUR NORTHWEST LATE MONDAY NIGHT WHILE ALL OTHER MODELS ARE DRY. ALL MODELS INDICATE SOME CLOUDS WITH THIS FEATURE WILL MOVE INTO OUR NORTH LATE MONDAY NIGHT. AS A COMPROMISE WILL MENTION A CHANCE OF FLURRIES NORTHWEST SECTIONS LATE MONDAY NIGHT. OTHERWISE...IT SHOULD REMAIN DRY. THIS SYSTEM WILL QUICKLY MOVE ON TO THE EAST TUESDAY. 850 MB TEMPERATURES WHICH WILL BE AROUND -5 TO -8 MONDAY WILL COOL TO -10 TO -13 CELSIUS TUESDAY. THUS SURFACE TEMPERATURES WILL BE A LITTLE COLDER TUESDAY AND EVEN COLDER ON WEDNESDAY AS MORE ARCTIC AIR PUSHES SOUTH INTO OUR REGION. IN MOST CASES MOS SEEMS TO TO HANDLING THIS OK AND ONLY MINOR TWEAKS MADE. && .LONG TERM /WEDNESDAY THROUGH SATURDAY NIGHT/... ISSUED AT 352 AM EST SUN DEC 28 2014 THE MAIN FOCUS OF THE LONG TERM PERIOD CONTINUES TO BE A LOW PRESSURE SYSTEM LATE IN THE PERIOD. FIRST...ZONAL FLOW ALOFT WILL RESULT IN DRY CONDITIONS FROM WEDNESDAY THROUGH THURSDAY. FOCUS THEN TURNS TO THE APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTHWEST. MOST RECENT MODEL RUNS ARE SHOWING BETTER CONSISTENCY IN THE TRACK COMPARED TO YESTERDAY. NOW THE GFS AND EURO ARE BOTH ON BOARD WITH THE LOW PRESSURE SYSTEM TRACKING FROM THE DESERT SOUTHWEST...ACROSS THE CENTRAL PLAINS...AND UP INTO CENTRAL INDIANA. LATEST INITIALIZATION WAS A TAD FAST WITH BRINGING PRECIP INTO SOUTHERN PORTIONS OF THE FORECAST AREA AS EARLY AS THURSDAY NIGHT. NONE OF THE MODELS SEEM TO BE TRENDING THAT FAST...SO REMOVED MENTION OF ANY PRECIP FOR THURSDAY NIGHT. PRECIP CHANCES WILL INCREASE QUICKLY BY FRIDAY AFTERNOON AS LOW PRESSURE SYSTEM TRAVERSES THE MISSOURI VALLEY. THE LIKELY POPS ON FRIDAY NIGHT THAT REGIONAL INITIALIZATION IS TRENDING TOWARD MATCH NICELY. SO...WILL NOT MAKE ANY DEVIATIONS TO POPS FOR FRIDAY AND SATURDAY. CONFIDENCE IN PRECIP TYPE IS STILL LOW UNTIL THE EXACT TRACK BECOMES SOLIDIFIED...BUT IT/S LOOKING LIKE SNOW OVER THE NORTHERN THIRD OF THE FORECAST AREA WITH RAIN/SNOW AND RAIN OVER THE REMAINING TWO-THIRDS OF CENTRAL INDIANA. && .AVIATION /DISCUSSION FOR THE 281800Z TAF ISSUANCE/... ISSUED AT 1213 PM EST SUN DEC 28 2014 MVFR CONDITIONS WILL PREVAIL FOR ABOUT 4-5 HOURS LONGER THAN EXPECTED EXCEPT FOR SITE KHUF WHICH HAS ALREADY SAW SOME SCATTERING OUT IN THE LOW LEVELS. THEN ALL SITES IMPROVING TO VFR CATEGORY BY LATE THIS AFTERNOON. (EARLY EVENING FOR SITE KBMG WHICH IS FARTHER TO THE SOUTH AND EAST.) AS HIGH PRESSURE STRENGTHENS OVER THE AREA...CLOUDS WILL SCATTER OUT FURTHER LATE IN TAF PERIOD AND REMAIN AT VFR CATEGORY. WINDS WILL BE NORTHERLY AND LIGHT AT 2 TO 6 KTS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH LONG TERM....TDUD AVIATION...SMF VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
922 AM EST SUN DEC 28 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 335 AM EST SUN DEC 28 2014 A COLD FRONT ACROSS OHIO AND NORTHWEST KENTUCKY WILL CONTINUE MOVING SOUTHEAST. THIS WILL BE FOLLOWED BY A RIDGE OF HIGH PRESSURE WHICH WILL MOVE SUNDAY NIGHT AND MONDAY. A DRY SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY FRIDAY AND ACROSS OUR REGION SATURDAY. && .NEAR TERM /TODAY AND TONIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 RADAR SHOWS PRECIPITATION WAS ENDING RAPIDLY FROM THE NORTHWEST AND WILL PRETTY MUCH BE DONE BY FORECAST RELEASE TIME. SOME SITES ACROSS OUR SOUTH AND SOUTHEAST MAY SEE A LITTLE DRIZZLE PRIOR TO 7AM. MAIN ISSUES TODAY WILL BE HOW LONG CLOUDS WILL REMAIN AND TEMPERATURES. SATELLITE SHOWS CLEARING LINE ACROSS NORTHWEST ILLINOIS. ALTHOUGH THERE HAVE BEEN A FEW HOLES FARTHER SOUTHEAST. THE RAP MODEL SOUNDINGS INDICATE MOSTLY CLOUDY SKIES THIS MORNING AND DECREASING CLOUDS FROM MIDDAY ON. EXPECT CLOUDS TO PERSIST OVER SOUTHERN SECTIONS MOST OF TODAY AS THIS WILL BE LAST AREA TO CLEAR OUT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE MIDDLE 30S NORTH TO AROUND 40 FAR SOUTH WHICH IS SLIGHTLY BELOW A MOS BLEND ON TEMPERATURES. TONIGHT WILL BECOME MOSTLY CLEAR AS WEAK RIDGE OF HIGH PRESSURE MOVES INTO OUR REGION. WENT CLOSE TO A MOS BLEND ON TEMPERATURES WITH LOWS IN THE LOWER 20S OVER NORTHERN SECTIONS AND THE MIDDLE AND UPPER 20S SOUTH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 MONDAY WILL BE SEASONABLY COOL WITH WEAK COLD ADVECTION AND HIGH PRESSURE BUILDING IN FROM THE NORTHWEST. LOW LEVEL THICKNESS INDICATE HIGHS SHOULD BE FROM THE MIDDLE 30S OVER NORTHERN SECTIONS TO AROUND 40 FAR SOUTH WITH MOSTLY SUNNY SKIES. MODELS INDICATE A WEAK UPPER DISTURBANCE WILL TRACK ACROSS INDIANA LATE MONDAY NIGHT AS A SECONDARY ARCTIC COLD FRONT MOVES OUR WAY. THE NAM SHOWS SOME QPF ACROSS OUR NORTHWEST LATE MONDAY NIGHT WHILE ALL OTHER MODELS ARE DRY. ALL MODELS INDICATE SOME CLOUDS WITH THIS FEATURE WILL MOVE INTO OUR NORTH LATE MONDAY NIGHT. AS A COMPROMISE WILL MENTION A CHANCE OF FLURRIES NORTHWEST SECTIONS LATE MONDAY NIGHT. OTHERWISE...IT SHOULD REMAIN DRY. THIS SYSTEM WILL QUICKLY MOVE ON TO THE EAST TUESDAY. 850 MB TEMPERATURES WHICH WILL BE AROUND -5 TO -8 MONDAY WILL COOL TO -10 TO -13 CELSIUS TUESDAY. THUS SURFACE TEMPERATURES WILL BE A LITTLE COLDER TUESDAY AND EVEN COLDER ON WEDNESDAY AS MORE ARCTIC AIR PUSHES SOUTH INTO OUR REGION. IN MOST CASES MOS SEEMS TO TO HANDLING THIS OK AND ONLY MINOR TWEAKS MADE. && .LONG TERM /WEDNESDAY THROUGH SATURDAY NIGHT/... ISSUED AT 352 AM EST SUN DEC 28 2014 THE MAIN FOCUS OF THE LONG TERM PERIOD CONTINUES TO BE A LOW PRESSURE SYSTEM LATE IN THE PERIOD. FIRST...ZONAL FLOW ALOFT WILL RESULT IN DRY CONDITIONS FROM WEDNESDAY THROUGH THURSDAY. FOCUS THEN TURNS TO THE APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTHWEST. MOST RECENT MODEL RUNS ARE SHOWING BETTER CONSISTENCY IN THE TRACK COMPARED TO YESTERDAY. NOW THE GFS AND EURO ARE BOTH ON BOARD WITH THE LOW PRESSURE SYSTEM TRACKING FROM THE DESERT SOUTHWEST...ACROSS THE CENTRAL PLAINS...AND UP INTO CENTRAL INDIANA. LATEST INITIALIZATION WAS A TAD FAST WITH BRINGING PRECIP INTO SOUTHERN PORTIONS OF THE FORECAST AREA AS EARLY AS THURSDAY NIGHT. NONE OF THE MODELS SEEM TO BE TRENDING THAT FAST...SO REMOVED MENTION OF ANY PRECIP FOR THURSDAY NIGHT. PRECIP CHANCES WILL INCREASE QUICKLY BY FRIDAY AFTERNOON AS LOW PRESSURE SYSTEM TRAVERSES THE MISSOURI VALLEY. THE LIKELY POPS ON FRIDAY NIGHT THAT REGIONAL INITIALIZATION IS TRENDING TOWARD MATCH NICELY. SO...WILL NOT MAKE ANY DEVIATIONS TO POPS FOR FRIDAY AND SATURDAY. CONFIDENCE IN PRECIP TYPE IS STILL LOW UNTIL THE EXACT TRACK BECOMES SOLIDIFIED...BUT IT/S LOOKING LIKE SNOW OVER THE NORTHERN THIRD OF THE FORECAST AREA WITH RAIN/SNOW AND RAIN OVER THE REMAINING TWO-THIRDS OF CENTRAL INDIANA. && .AVIATION /DISCUSSION FOR THE 281200Z TAF ISSUANCE/... ISSUED AT 920 AM EST SUN DEC 28 2014 1420Z UPDATE...NO CHANGES NEEDED AT THIS TIME. PREVIOUS DISCUSSION FOLLOWS. RESIDUAL CLOUD COVER WILL LINGER ACROSS TAF SITES FOR MOST OF TODAY. MVFR CONDITIONS WILL BE THE PREVAILING FLIGHT CATEGORY THROUGH THE REMAINDER OF THIS MORNING...THEN IMPROVING TO VFR CATEGORY BY EARLY AFTERNOON AS CEILINGS RISE. AS HIGH PRESSURE STRENGTHENS OVER THE AREA...CLOUDS WILL SCATTER OUT FURTHER LATE IN TAF PERIOD AND REMAIN AT VFR CATEGORY. WINDS WILL BE NORTHERLY AT 2 TO 6 KTS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH LONG TERM....TDUD AVIATION...SMF/TDUD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
631 AM EST SUN DEC 28 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 335 AM EST SUN DEC 28 2014 A COLD FRONT ACROSS OHIO AND NORTHWEST KENTUCKY WILL CONTINUE MOVING SOUTHEAST. THIS WILL BE FOLLOWED BY A RIDGE OF HIGH PRESSURE WHICH WILL MOVE SUNDAY NIGHT AND MONDAY. A DRY SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY FRIDAY AND ACROSS OUR REGION SATURDAY. && .NEAR TERM /TODAY AND TONIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 RADAR SHOWS PRECIPITATION WAS ENDING RAPIDLY FROM THE NORTHWEST AND WILL PRETTY MUCH BE DONE BY FORECAST RELEASE TIME. SOME SITES ACROSS OUR SOUTH AND SOUTHEAST MAY SEE A LITTLE DRIZZLE PRIOR TO 7AM. MAIN ISSUES TODAY WILL BE HOW LONG CLOUDS WILL REMAIN AND TEMPERATURES. SATELLITE SHOWS CLEARING LINE ACROSS NORTHWEST ILLINOIS. ALTHOUGH THERE HAVE BEEN A FEW HOLES FARTHER SOUTHEAST. THE RAP MODEL SOUNDINGS INDICATE MOSTLY CLOUDY SKIES THIS MORNING AND DECREASING CLOUDS FROM MIDDAY ON. EXPECT CLOUDS TO PERSIST OVER SOUTHERN SECTIONS MOST OF TODAY AS THIS WILL BE LAST AREA TO CLEAR OUT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE MIDDLE 30S NORTH TO AROUND 40 FAR SOUTH WHICH IS SLIGHTLY BELOW A MOS BLEND ON TEMPERATURES. TONIGHT WILL BECOME MOSTLY CLEAR AS WEAK RIDGE OF HIGH PRESSURE MOVES INTO OUR REGION. WENT CLOSE TO A MOS BLEND ON TEMPERATURES WITH LOWS IN THE LOWER 20S OVER NORTHERN SECTIONS AND THE MIDDLE AND UPPER 20S SOUTH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 MONDAY WILL BE SEASONABLY COOL WITH WEAK COLD ADVECTION AND HIGH PRESSURE BUILDING IN FROM THE NORTHWEST. LOW LEVEL THICKNESS INDICATE HIGHS SHOULD BE FROM THE MIDDLE 30S OVER NORTHERN SECTIONS TO AROUND 40 FAR SOUTH WITH MOSTLY SUNNY SKIES. MODELS INDICATE A WEAK UPPER DISTURBANCE WILL TRACK ACROSS INDIANA LATE MONDAY NIGHT AS A SECONDARY ARCTIC COLD FRONT MOVES OUR WAY. THE NAM SHOWS SOME QPF ACROSS OUR NORTHWEST LATE MONDAY NIGHT WHILE ALL OTHER MODELS ARE DRY. ALL MODELS INDICATE SOME CLOUDS WITH THIS FEATURE WILL MOVE INTO OUR NORTH LATE MONDAY NIGHT. AS A COMPROMISE WILL MENTION A CHANCE OF FLURRIES NORTHWEST SECTIONS LATE MONDAY NIGHT. OTHERWISE...IT SHOULD REMAIN DRY. THIS SYSTEM WILL QUICKLY MOVE ON TO THE EAST TUESDAY. 850 MB TEMPERATURES WHICH WILL BE AROUND -5 TO -8 MONDAY WILL COOL TO -10 TO -13 CELSIUS TUESDAY. THUS SURFACE TEMPERATURES WILL BE A LITTLE COLDER TUESDAY AND EVEN COLDER ON WEDNESDAY AS MORE ARCTIC AIR PUSHES SOUTH INTO OUR REGION. IN MOST CASES MOS SEEMS TO TO HANDLING THIS OK AND ONLY MINOR TWEAKS MADE. && .LONG TERM /WEDNESDAY THROUGH SATURDAY NIGHT/... ISSUED AT 352 AM EST SUN DEC 28 2014 THE MAIN FOCUS OF THE LONG TERM PERIOD CONTINUES TO BE A LOW PRESSURE SYSTEM LATE IN THE PERIOD. FIRST...ZONAL FLOW ALOFT WILL RESULT IN DRY CONDITIONS FROM WEDNESDAY THROUGH THURSDAY. FOCUS THEN TURNS TO THE APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTHWEST. MOST RECENT MODEL RUNS ARE SHOWING BETTER CONSISTENCY IN THE TRACK COMPARED TO YESTERDAY. NOW THE GFS AND EURO ARE BOTH ON BOARD WITH THE LOW PRESSURE SYSTEM TRACKING FROM THE DESERT SOUTHWEST...ACROSS THE CENTRAL PLAINS...AND UP INTO CENTRAL INDIANA. LATEST INITIALIZATION WAS A TAD FAST WITH BRINGING PRECIP INTO SOUTHERN PORTIONS OF THE FORECAST AREA AS EARLY AS THURSDAY NIGHT. NONE OF THE MODELS SEEM TO BE TRENDING THAT FAST...SO REMOVED MENTION OF ANY PRECIP FOR THURSDAY NIGHT. PRECIP CHANCES WILL INCREASE QUICKLY BY FRIDAY AFTERNOON AS LOW PRESSURE SYSTEM TRAVERSES THE MISSOURI VALLEY. THE LIKELY POPS ON FRIDAY NIGHT THAT REGIONAL INITIALIZATION IS TRENDING TOWARD MATCH NICELY. SO...WILL NOT MAKE ANY DEVIATIONS TO POPS FOR FRIDAY AND SATURDAY. CONFIDENCE IN PRECIP TYPE IS STILL LOW UNTIL THE EXACT TRACK BECOMES SOLIDIFIED...BUT IT/S LOOKING LIKE SNOW OVER THE NORTHERN THIRD OF THE FORECAST AREA WITH RAIN/SNOW AND RAIN OVER THE REMAINING TWO-THIRDS OF CENTRAL INDIANA. && .AVIATION /DISCUSSION FOR THE 28/1200Z TAF ISSUANCE/... ISSUED AT 624 AM EST SUN DEC 28 2014 RESIDUAL CLOUD COVER WILL LINGER ACROSS TAF SITES FOR MOST OF TODAY. MVFR CONDITIONS WILL BE THE PREVAILING FLIGHT CATEGORY THROUGH THE REMAINDER OF THIS MORNING...THEN IMPROVING TO VFR CATEGORY BY EARLY AFTERNOON AS CEILINGS RISE. AS HIGH PRESSURE STRENGTHENS OVER THE AREA...CLOUDS WILL SCATTER OUT FURTHER LATE IN TAF PERIOD AND REMAIN AT VFR CATEGORY. WINDS WILL BE NORTHERLY AT 2 TO 6 KTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH LONG TERM....TDUD AVIATION...TDUD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
353 AM EST SUN DEC 28 2014 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 335 AM EST SUN DEC 28 2014 A COLD FRONT ACROSS OHIO AND NORTHWEST KENTUCKY WILL CONTINUE MOVING SOUTHEAST. THIS WILL BE FOLLOWED BY A RIDGE OF HIGH PRESSURE WHICH WILL MOVE SUNDAY NIGHT AND MONDAY. A DRY SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY FRIDAY AND ACROSS OUR REGION SATURDAY. && .NEAR TERM /TODAY AND TONIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 RADAR SHOWS PRECIPITATION WAS ENDING RAPIDLY FROM THE NORTHWEST AND WILL PRETTY MUCH BE DONE BY FORECAST RELEASE TIME. SOME SITES ACROSS OUR SOUTH AND SOUTHEAST MAY SEE A LITTLE DRIZZLE PRIOR TO 7AM. MAIN ISSUES TODAY WILL BE HOW LONG CLOUDS WILL REMAIN AND TEMPERATURES. SATELLITE SHOWS CLEARING LINE ACROSS NORTHWEST ILLINOIS. ALTHOUGH THERE HAVE BEEN A FEW HOLES FARTHER SOUTHEAST. THE RAP MODEL SOUNDINGS INDICATE MOSTLY CLOUDY SKIES THIS MORNING AND DECREASING CLOUDS FROM MIDDAY ON. EXPECT CLOUDS TO PERSIST OVER SOUTHERN SECTIONS MOST OF TODAY AS THIS WILL BE LAST AREA TO CLEAR OUT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE MIDDLE 30S NORTH TO AROUND 40 FAR SOUTH WHICH IS SLIGHTLY BELOW A MOS BLEND ON TEMPERATURES. TONIGHT WILL BECOME MOSTLY CLEAR AS WEAK RIDGE OF HIGH PRESSURE MOVES INTO OUR REGION. WENT CLOSE TO A MOS BLEND ON TEMPERATURES WITH LOWS IN THE LOWER 20S OVER NORTHERN SECTIONS AND THE MIDDLE AND UPPER 20S SOUTH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 MONDAY WILL BE SEASONABLY COOL WITH WEAK COLD ADVECTION AND HIGH PRESSURE BUILDING IN FROM THE NORTHWEST. LOW LEVEL THICKNESS INDICATE HIGHS SHOULD BE FROM THE MIDDLE 30S OVER NORTHERN SECTIONS TO AROUND 40 FAR SOUTH WITH MOSTLY SUNNY SKIES. MODELS INDICATE A WEAK UPPER DISTURBANCE WILL TRACK ACROSS INDIANA LATE MONDAY NIGHT AS A SECONDARY ARCTIC COLD FRONT MOVES OUR WAY. THE NAM SHOWS SOME QPF ACROSS OUR NORTHWEST LATE MONDAY NIGHT WHILE ALL OTHER MODELS ARE DRY. ALL MODELS INDICATE SOME CLOUDS WITH THIS FEATURE WILL MOVE INTO OUR NORTH LATE MONDAY NIGHT. AS A COMPROMISE WILL MENTION A CHANCE OF FLURRIES NORTHWEST SECTIONS LATE MONDAY NIGHT. OTHERWISE...IT SHOULD REMAIN DRY. THIS SYSTEM WILL QUICKLY MOVE ON TO THE EAST TUESDAY. 850 MB TEMPERATURES WHICH WILL BE AROUND -5 TO -8 MONDAY WILL COOL TO -10 TO -13 CELSIUS TUESDAY. THUS SURFACE TEMPERATURES WILL BE A LITTLE COLDER TUESDAY AND EVEN COLDER ON WEDNESDAY AS MORE ARCTIC AIR PUSHES SOUTH INTO OUR REGION. IN MOST CASES MOS SEEMS TO TO HANDLING THIS OK AND ONLY MINOR TWEAKS MADE. && .LONG TERM /WEDNESDAY THROUGH SATURDAY NIGHT/... ISSUED AT 352 AM EST SUN DEC 28 2014 THE MAIN FOCUS OF THE LONG TERM PERIOD CONTINUES TO BE A LOW PRESSURE SYSTEM LATE IN THE PERIOD. FIRST...ZONAL FLOW ALOFT WILL RESULT IN DRY CONDITIONS FROM WEDNESDAY THROUGH THURSDAY. FOCUS THEN TURNS TO THE APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTHWEST. MOST RECENT MODEL RUNS ARE SHOWING BETTER CONSISTENCY IN THE TRACK COMPARED TO YESTERDAY. NOW THE GFS AND EURO ARE BOTH ON BOARD WITH THE LOW PRESSURE SYSTEM TRACKING FROM THE DESERT SOUTHWEST...ACROSS THE CENTRAL PLAINS...AND UP INTO CENTRAL INDIANA. LATEST INITIALIZATION WAS A TAD FAST WITH BRINGING PRECIP INTO SOUTHERN PORTIONS OF THE FORECAST AREA AS EARLY AS THURSDAY NIGHT. NONE OF THE MODELS SEEM TO BE TRENDING THAT FAST...SO REMOVED MENTION OF ANY PRECIP FOR THURSDAY NIGHT. PRECIP CHANCES WILL INCREASE QUICKLY BY FRIDAY AFTERNOON AS LOW PRESSURE SYSTEM TRAVERSES THE MISSOURI VALLEY. THE LIKELY POPS ON FRIDAY NIGHT THAT REGIONAL INITIALIZATION IS TRENDING TOWARD MATCH NICELY. SO...WILL NOT MAKE ANY DEVIATIONS TO POPS FOR FRIDAY AND SATURDAY. CONFIDENCE IN PRECIP TYPE IS STILL LOW UNTIL THE EXACT TRACK BECOMES SOLIDIFIED...BUT IT/S LOOKING LIKE SNOW OVER THE NORTHERN THIRD OF THE FORECAST AREA WITH RAIN/SNOW AND RAIN OVER THE REMAINING TWO-THIRDS OF CENTRAL INDIANA. && .AVIATION /DISCUSSION FOR THE 28/0900Z TAF UPDATE/... ISSUED AT 324 AM EST SUN DEC 28 2014 UPDATE... MVFR CONDITIONS ARE PREVAILING AT KIND AND WILL CONTINUE THROUGH THE MORNING. PREVIOUS DISCUSSION... WINDS TO REMAIN BELOW 10 KNOTS THROUGH THE FORECAST. RAIN HAS ENDED AT ALL TAF SITES EXCEPT KBMG BUT SHOULD ALSO END THERE WITHIN THE HOUR OR AROUND 280700Z. WITHIN COLD AND DRY AIR ADVECTING IN...VISIBILITY HAS IMPROVED TO 6+ MILES AND WILL REMAIN THAT WAY THROUGH THE FORECAST. MULTIPLE CLOUD LAYERS HAVE BEEN OBSERVED ACROSS ILLINOIS BUT SEEM TO BE SETTLING TOWARDS DECKS OF 1800-2200 FEET AND THESE SHOULD PREVAIL THROUGH THE MORNING. AS HIGH PRESSURE CONTINUES BUILDING IN AND SUBSIDENCE BEGINS TO DRY THIS LOWER LAYER EXPECT BREAKS IN THE 2000 FOOT DECK AROUND 281800Z AND EVENTUAL CLEARING OF ALL CLOUDS BY 290000Z. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH LONG TERM....TDUD AVIATION...DT/TDUD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
335 AM EST SUN DEC 28 2014 .UPDATE... SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 335 AM EST SUN DEC 28 2014 A COLD FRONT ACROSS OHIO AND NORTHWEST KENTUCKY WILL CONTINUE MOVING SOUTHEAST. THIS WILL BE FOLLOWED BY A RIDGE OF HIGH PRESSURE WHICH WILL MOVE SUNDAY NIGHT AND MONDAY. A DRY SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY FRIDAY AND ACROSS OUR REGION SATURDAY. && .NEAR TERM /TODAY AND TONIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 RADAR SHOWS PRECIPITATION WAS ENDING RAPIDLY FROM THE NORTHWEST AND WILL PRETTY MUCH BE DONE BY FORECAST RELEASE TIME. SOME SITES ACROSS OUR SOUTH AND SOUTHEAST MAY SEE A LITTLE DRIZZLE PRIOR TO 7AM. MAIN ISSUES TODAY WILL BE HOW LONG CLOUDS WILL REMAIN AND TEMPERATURES. SATELLITE SHOWS CLEARING LINE ACROSS NORTHWEST ILLINOIS. ALTHOUGH THERE HAVE BEEN A FEW HOLES FARTHER SOUTHEAST. THE RAP MODEL SOUNDINGS INDICATE MOSTLY CLOUDY SKIES THIS MORNING AND DECREASING CLOUDS FROM MIDDAY ON. EXPECT CLOUDS TO PERSIST OVER SOUTHERN SECTIONS MOST OF TODAY AS THIS WILL BE LAST AREA TO CLEAR OUT. HIGH TEMPERATURES TODAY WILL RANGE FROM THE MIDDLE 30S NORTH TO AROUND 40 FAR SOUTH WHICH IS SLIGHTLY BELOW A MOS BLEND ON TEMPERATURES. TONIGHT WILL BECOME MOSTLY CLEAR AS WEAK RIDGE OF HIGH PRESSURE MOVES INTO OUR REGION. WENT CLOSE TO A MOS BLEND ON TEMPERATURES WITH LOWS IN THE LOWER 20S OVER NORTHERN SECTIONS AND THE MIDDLE AND UPPER 20S SOUTH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... ISSUED AT 335 AM EST SUN DEC 28 2014 MONDAY WILL BE SEASONABLY COOL WITH WEAK COLD ADVECTION AND HIGH PRESSURE BUILDING IN FROM THE NORTHWEST. LOW LEVEL THICKNESS INDICATE HIGHS SHOULD BE FROM THE MIDDLE 30S OVER NORTHERN SECTIONS TO AROUND 40 FAR SOUTH WITH MOSTLY SUNNY SKIES. MODELS INDICATE A WEAK UPPER DISTURBANCE WILL TRACK ACROSS INDIANA LATE MONDAY NIGHT AS A SECONDARY ARCTIC COLD FRONT MOVES OUR WAY. THE NAM SHOWS SOME QPF ACROSS OUR NORTHWEST LATE MONDAY NIGHT WHILE ALL OTHER MODELS ARE DRY. ALL MODELS INDICATE SOME CLOUDS WITH THIS FEATURE WILL MOVE INTO OUR NORTH LATE MONDAY NIGHT. AS A COMPROMISE WILL MENTION A CHANCE OF FLURRIES NORTHWEST SECTIONS LATE MONDAY NIGHT. OTHERWISE...IT SHOULD REMAIN DRY. THIS SYSTEM WILL QUICKLY MOVE ON TO THE EAST TUESDAY. 850 MB TEMPERATURES WHICH WILL BE AROUND -5 TO -8 MONDAY WILL COOL TO -10 TO -13 CELSIUS TUESDAY. THUS SURFACE TEMPERATURES WILL BE A LITTLE COLDER TUESDAY AND EVEN COLDER ON WEDNESDAY AS MORE ARCTIC AIR PUSHES SOUTH INTO OUR REGION. IN MOST CASES MOS SEEMS TO TO HANDLING THIS OK AND ONLY MINOR TWEAKS MADE. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ISSUED AT 240 PM EST SAT DEC 27 2014 MAIN FOCUS FOR THE EXTENDED PERIOD WILL BE POPS AND PRECIPITATION TYPE STARTING FRIDAY. PRIOR TO THAT...TEMPERATURES WILL BE THE BIGGEST ISSUE AS STRONG COLD WESTERN CANADIAN HIGH PRESSURE WILL SETTLE ACROSS THE OHIO VALLEY TO END THE OLD YEAR AND START THE NEW ONE. DETERMINISTIC MODELS ARE IN DECENT AGREEMENT THAT AN UPPER LOW WILL BE OVER NORTHEASTERN ARIZONA DURING THE EVENING OF THE FIRST DAY OF 2015. HOWEVER...THE MODELS THEN DIVERGE RAPIDLY WITH THE MUCH QUICKER 12Z GFS BRINGING A STRONGER SURFACE SYSTEM BUT WEAK UPPER WAVE OVER THE OHIO VALLEY FRIDAY NIGHT. MEANWHILE...THE 12Z ECMWF HAS EVEN A WEAKER BUT MUCH SLOWER WAVE LIFT NORTHEAST TO SOUTHERN ILLINOIS BY NEXT SATURDAY EVENING. THE EURO ALSO HAS THE MAIN SURFACE LOW WELL SOUTHWEST OF THE 12Z GFS POSITION SATURDAY EVENING. THE ECMWF HAS THE SURFACE LOW OVER EASTERN KENTUCKY...WHILE THE GFS HAS IT OVER SOUTHERN QUEBEC. DESPITE ALL THESE DIFFERENCES...BOTH MODELS START THE QPF ON FRIDAY WITH THE HEAVIEST PRECIPITATION ALONG THE OHIO RIVER. MEANWHILE...THE EURO WAS HOLDING MORE QPF AROUND ON SUNDAY THAN THE GFS. SO...STILL EXPECT THE PRECIPITATION TO SPREAD NORTHEAST ACROSS THE AREA ON FRIDAY. WITH CONFIDENCE IN TIMING LOW...WILL ACCEPT THE REGIONAL BLEND THAT KEEPS DECENT POPS AROUND NEXT SATURDAY AS HINTED AT BY THE EURO. REGARDING PRECIPITATION TYPE...WILL NOT MAKE MANY CHANGES WITH THE MODEL DIFFERENCES. CONFIDENCE NOT GOOD AS TO WHERE THE RAIN/SNOW LINE WILL BE IN SPACE AND TIME. HOWEVER...NORTHEASTERN PARTS OF THE FORECAST AREA WILL BE MORE LIKELY TO SEE FROZEN OR MIXED PRECIPITATION THEN THE SOUTHWESTERN ONES ON FRIDAY BASED ON THERMAL PROFILES FROM BUFKIT SOUNDINGS AS WELL AS PARTIAL THICKNESSES. FRIDAY NIGHT AND SATURDAY...THE NORTHWESTERN COUNTIES WOULD HAVE A HIGHER CHANCE OF MIXED OR FROZEN PRECIPITATION THAN THE SOUTHEAST AS COLDER AIR MOVES IN FROM THE NORTHWEST IN THE WAKE OF THE SURFACE SYSTEM. BUFKIT SOUNDINGS EVEN SUGGEST FREEZING RAIN OR SLEET COULD POSSIBLY MIX IN AT TIMES FRIDAY NIGHT. GENERALLY ACCEPTED THE REGIONAL BLEND TEMPERATURES. DO NOT FEEL CONFIDENT ENOUGH TO MAKE CHANGES UNTIL THE MODELS HOPEFULLY COME CLOSER TOGETHER IN SUBSEQUENT RUNS. AFTERNOON HIGHS IN THE 20S LOOK GOOD ON NEW YEAR`S DAY WITH HIGHS MOSTLY IN THE 30S THEREAFTER. MEANWHILE...NEW YEARS EVE NIGHT SHOULD BE THE COLDEST WITH OVERNIGHT LOWS IN THE TEENS FOR THE FIRST SUNRISE OF THE YEAR. OVERNIGHT LOWS WILL MOSTLY BE IN THE 20S AND 30S BY LATE WEEK. && .AVIATION /DISCUSSION FOR THE 28/0900Z TAF UPDATE/... ISSUED AT 324 AM EST SUN DEC 28 2014 UPDATE... MVFR CONDITIONS ARE PREVAILING AT KIND AND WILL CONTINUE THROUGH THE MORNING. PREVIOUS DISCUSSION... WINDS TO REMAIN BELOW 10 KNOTS THROUGH THE FORECAST. RAIN HAS ENDED AT ALL TAF SITES EXCEPT KBMG BUT SHOULD ALSO END THERE WITHIN THE HOUR OR AROUND 280700Z. WITHIN COLD AND DRY AIR ADVECTING IN...VISIBILITY HAS IMPROVED TO 6+ MILES AND WILL REMAIN THAT WAY THROUGH THE FORECAST. MULTIPLE CLOUD LAYERS HAVE BEEN OBSERVED ACROSS ILLINOIS BUT SEEM TO BE SETTLING TOWARDS DECKS OF 1800-2200 FEET AND THESE SHOULD PREVAIL THROUGH THE MORNING. AS HIGH PRESSURE CONTINUES BUILDING IN AND SUBSIDENCE BEGINS TO DRY THIS LOWER LAYER EXPECT BREAKS IN THE 2000 FOOT DECK AROUND 281800Z AND EVENTUAL CLEARING OF ALL CLOUDS BY 290000Z. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...JH LONG TERM...MK AVIATION...DT/TDUD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
329 AM EST SUN DEC 28 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 324 PM EST SAT DEC 27 2014 A COLD FRONT WILL MOVE EAST ACROSS OUR REGION TONIGHT. A DRY SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY. && .NEAR TERM /TONIGHT/... ISSUED AT 845 PM EST SAT DEC 27 2014 UPDATED TO REFLECT LATEST PROGRESSION OF BAND OF PRECIP INTO THE NORTHWESTERN FORECAST AREA AND ACROSS THE AREA THIS EVENING INTO THE OVERNIGHT. EXPECT THERE WILL BE PERIODS OF RAIN AND SNOW...PERIODS OF EITHER...AND PERHAPS SOME SLEET AS WELL IN MOST AREAS...BUT WITH LITTLE OR NO ACCUMULATION AS TEMPERATURES REMAIN ABOVE FREEZING AND MAY DO SO FOR SEVERAL MORE HOURS IF NOT ALL NIGHT ACROSS SOME PORTIONS OF THE AREA. HAVE ALSO SPED UP ENDING OF PRECIP A BIT BASED ON LATEST MODEL GUIDANCE. PREVIOUS DISCUSSION FOLLOWS. ISSUED AT 324 PM EST SAT DEC 27 2014 TRENDS AMONG THE MODELS REMAIN VIRTUALLY THE SAME...WITH THE EURO AND NAM BEING MUCH MORE PROGRESSIVE THAN THE GFS AND GEM. AS USUAL...THE SREF AND HRRR TAKE A DECENT BLEND OF THE FASTER AND SLOWER SOLUTIONS...SO LEANED HEAVILY TOWARD THIS GUIDANCE WHEN CREATING THE POPS FOR TONIGHT. ALSO TRIED TO WORK IN WHAT IS CURRENTLY ON THE RADAR SCOPE WITH ONE WAVE OF LIGHT RAIN MOVING IN FROM THE SOUTH...WHICH WILL LATER THE EXIT THE FORECAST AREA BY 00Z. WHILE THE MAIN AREA OF PRECIPITATION IS BEGINNING TO APPROACH THE CENTRAL INDIANA AREA FROM CENTRAL ILLINOIS. THIS AREA WILL MAKE IT/S WAY THROUGH THE BULK OF CENTRAL INDIANA FROM 00Z TO 08Z. WITH A FEW COUNTIES TO THE SOUTHEAST COUNTIES SEEING SOME LINGERING POPS INTO EARLY SUNDAY MORNING. ATTENTION THEN TURNS TO PRECIP TYPE AND TIMING...BOTH OF WHICH WILL BE TRICKY. ALL OF THE PRECIP OVER CENTRAL INDIANA WILL BE IN THE FORM OF RAIN THROUGH THIS EVENING. COLDER AIR WILL BEGIN WORKING INTO THE NORTHWEST COUNTIES OF THE CWA ABOUT MIDNIGHT AND PUSH TOWARD THE I-70 CORRIDOR BY 2-3 AM. BEST CHANCE IN TERMS OF PRECIP TYPE ARE STILL A -RA/SN MIX...CANNOT RULE OUT ANY SLEET MIXING IN AT TIMES HOWEVER NOT WIDESPREAD ENOUGH TO HAVE THE CONFIDENCE TO INCLUDE IT IN FORECAST AT THIS TIME. THIS MIX WILL WORK IT/S WAY TOWARD THE E/SE EARLY SUNDAY MORNING...WHILE PRECIP BEHIND IT BEGINS TO WIND DOWN AND DRY OUT OVER MOST OF THE FORECAST AREA BY 12Z SUNDAY MORNING. LOWS 31-36. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... ISSUED AT 324 PM EST SAT DEC 27 2014 AS MENTIONED IN ABOVE DISCUSSION...THERE WILL LIKELY BE SOME REMNANT MIXTURE OF -RA/SN FOR EARLY SUNDAY MORNING ACROSS SEVERAL OF THE SOUTHEASTERN COUNTIES BEFORE THAT FRONT MOVES FARTHER FROM THE AREA AND DRIER AND COLDER AIR FILTERS BACK INTO THE AREA. WILL CONTINUE LOW CHANCE POPS THERE AT LEAST THROUGH 14-15Z SUNDAY MORNING. DRY AND COOLER WEATHER WILL PERSIST ACROSS THE REGION FOR THE BETTER HALF OF THE NEXT WEEK AS A LARGE AREA OF HIGH PRESSURE REMAINS IN CONTROL OVER THE REGION. MODELS INDICATE HIGHS IN THE UPPER 30S SUNDAY AND PERHAPS A DEGREE OR TWO WARMER MONDAY. LOWS WILL BE IN THE MIDDLE TO UPPER 20S SUNDAY NIGHT AND LOWER OR MIDDLE 20S MONDAY NIGHT AS A DRY SECONDARY COLD FRONT MOVES THROUGH. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ISSUED AT 240 PM EST SAT DEC 27 2014 MAIN FOCUS FOR THE EXTENDED PERIOD WILL BE POPS AND PRECIPITATION TYPE STARTING FRIDAY. PRIOR TO THAT...TEMPERATURES WILL BE THE BIGGEST ISSUE AS STRONG COLD WESTERN CANADIAN HIGH PRESSURE WILL SETTLE ACROSS THE OHIO VALLEY TO END THE OLD YEAR AND START THE NEW ONE. DETERMINISTIC MODELS ARE IN DECENT AGREEMENT THAT AN UPPER LOW WILL BE OVER NORTHEASTERN ARIZONA DURING THE EVENING OF THE FIRST DAY OF 2015. HOWEVER...THE MODELS THEN DIVERGE RAPIDLY WITH THE MUCH QUICKER 12Z GFS BRINGING A STRONGER SURFACE SYSTEM BUT WEAK UPPER WAVE OVER THE OHIO VALLEY FRIDAY NIGHT. MEANWHILE...THE 12Z ECMWF HAS EVEN A WEAKER BUT MUCH SLOWER WAVE LIFT NORTHEAST TO SOUTHERN ILLINOIS BY NEXT SATURDAY EVENING. THE EURO ALSO HAS THE MAIN SURFACE LOW WELL SOUTHWEST OF THE 12Z GFS POSITION SATURDAY EVENING. THE ECMWF HAS THE SURFACE LOW OVER EASTERN KENTUCKY...WHILE THE GFS HAS IT OVER SOUTHERN QUEBEC. DESPITE ALL THESE DIFFERENCES...BOTH MODELS START THE QPF ON FRIDAY WITH THE HEAVIEST PRECIPITATION ALONG THE OHIO RIVER. MEANWHILE...THE EURO WAS HOLDING MORE QPF AROUND ON SUNDAY THAN THE GFS. SO...STILL EXPECT THE PRECIPITATION TO SPREAD NORTHEAST ACROSS THE AREA ON FRIDAY. WITH CONFIDENCE IN TIMING LOW...WILL ACCEPT THE REGIONAL BLEND THAT KEEPS DECENT POPS AROUND NEXT SATURDAY AS HINTED AT BY THE EURO. REGARDING PRECIPITATION TYPE...WILL NOT MAKE MANY CHANGES WITH THE MODEL DIFFERENCES. CONFIDENCE NOT GOOD AS TO WHERE THE RAIN/SNOW LINE WILL BE IN SPACE AND TIME. HOWEVER...NORTHEASTERN PARTS OF THE FORECAST AREA WILL BE MORE LIKELY TO SEE FROZEN OR MIXED PRECIPITATION THEN THE SOUTHWESTERN ONES ON FRIDAY BASED ON THERMAL PROFILES FROM BUFKIT SOUNDINGS AS WELL AS PARTIAL THICKNESSES. FRIDAY NIGHT AND SATURDAY...THE NORTHWESTERN COUNTIES WOULD HAVE A HIGHER CHANCE OF MIXED OR FROZEN PRECIPITATION THAN THE SOUTHEAST AS COLDER AIR MOVES IN FROM THE NORTHWEST IN THE WAKE OF THE SURFACE SYSTEM. BUFKIT SOUNDINGS EVEN SUGGEST FREEZING RAIN OR SLEET COULD POSSIBLY MIX IN AT TIMES FRIDAY NIGHT. GENERALLY ACCEPTED THE REGIONAL BLEND TEMPERATURES. DO NOT FEEL CONFIDENT ENOUGH TO MAKE CHANGES UNTIL THE MODELS HOPEFULLY COME CLOSER TOGETHER IN SUBSEQUENT RUNS. AFTERNOON HIGHS IN THE 20S LOOK GOOD ON NEW YEAR`S DAY WITH HIGHS MOSTLY IN THE 30S THEREAFTER. MEANWHILE...NEW YEARS EVE NIGHT SHOULD BE THE COLDEST WITH OVERNIGHT LOWS IN THE TEENS FOR THE FIRST SUNRISE OF THE YEAR. OVERNIGHT LOWS WILL MOSTLY BE IN THE 20S AND 30S BY LATE WEEK. && .AVIATION /DISCUSSION FOR THE 28/0900Z TAF UPDATE/... ISSUED AT 324 AM EST SUN DEC 28 2014 UPDATE... MVFR CONDITIONS ARE PREVAILING AT KIND AND WILL CONTINUE THROUGH THE MORNING. PREVIOUS DISCUSSION... WINDS TO REMAIN BELOW 10 KNOTS THROUGH THE FORECAST. RAIN HAS ENDED AT ALL TAF SITES EXCEPT KBMG BUT SHOULD ALSO END THERE WITHIN THE HOUR OR AROUND 280700Z. WITHIN COLD AND DRY AIR ADVECTING IN...VISIBILITY HAS IMPROVED TO 6+ MILES AND WILL REMAIN THAT WAY THROUGH THE FORECAST. MULTIPLE CLOUD LAYERS HAVE BEEN OBSERVED ACROSS ILLINOIS BUT SEEM TO BE SETTLING TOWARDS DECKS OF 1800-2200 FEET AND THESE SHOULD PREVAIL THROUGH THE MORNING. AS HIGH PRESSURE CONTINUES BUILDING IN AND SUBSIDENCE BEGINS TO DRY THIS LOWER LAYER EXPECT BREAKS IN THE 2000 FOOT DECK AROUND 281800Z AND EVENTUAL CLEARING OF ALL CLOUDS BY 290000Z. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...SMF NEAR TERM...SMF/NIELD SHORT TERM...SMF LONG TERM...MK AVIATION...DT/TDUD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1212 AM EST SUN DEC 28 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 324 PM EST SAT DEC 27 2014 A COLD FRONT WILL MOVE EAST ACROSS OUR REGION TONIGHT. A DRY SECONDARY ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS OUR REGION AROUND TUESDAY. IN THE LONG TERM AN ARCTIC HIGH PRESSURE SYSTEM WILL BRING DRY AND COLD WEATHER. HOWEVER MIXED PRECIPITATION IS POSSIBLE AGAIN THIS FRIDAY THROUGH NEXT SATURDAY AS MODELS SHOW A LOW PRESSURE SYSTEM MOVING INTO THE LOWER MISSISSIPPI VALLEY. && .NEAR TERM /TONIGHT/... ISSUED AT 845 PM EST SAT DEC 27 2014 UPDATED TO REFLECT LATEST PROGRESSION OF BAND OF PRECIP INTO THE NORTHWESTERN FORECAST AREA AND ACROSS THE AREA THIS EVENING INTO THE OVERNIGHT. EXPECT THERE WILL BE PERIODS OF RAIN AND SNOW...PERIODS OF EITHER...AND PERHAPS SOME SLEET AS WELL IN MOST AREAS...BUT WITH LITTLE OR NO ACCUMULATION AS TEMPERATURES REMAIN ABOVE FREEZING AND MAY DO SO FOR SEVERAL MORE HOURS IF NOT ALL NIGHT ACROSS SOME PORTIONS OF THE AREA. HAVE ALSO SPED UP ENDING OF PRECIP A BIT BASED ON LATEST MODEL GUIDANCE. PREVIOUS DISCUSSION FOLLOWS. ISSUED AT 324 PM EST SAT DEC 27 2014 TRENDS AMONG THE MODELS REMAIN VIRTUALLY THE SAME...WITH THE EURO AND NAM BEING MUCH MORE PROGRESSIVE THAN THE GFS AND GEM. AS USUAL...THE SREF AND HRRR TAKE A DECENT BLEND OF THE FASTER AND SLOWER SOLUTIONS...SO LEANED HEAVILY TOWARD THIS GUIDANCE WHEN CREATING THE POPS FOR TONIGHT. ALSO TRIED TO WORK IN WHAT IS CURRENTLY ON THE RADAR SCOPE WITH ONE WAVE OF LIGHT RAIN MOVING IN FROM THE SOUTH...WHICH WILL LATER THE EXIT THE FORECAST AREA BY 00Z. WHILE THE MAIN AREA OF PRECIPITATION IS BEGINNING TO APPROACH THE CENTRAL INDIANA AREA FROM CENTRAL ILLINOIS. THIS AREA WILL MAKE IT/S WAY THROUGH THE BULK OF CENTRAL INDIANA FROM 00Z TO 08Z. WITH A FEW COUNTIES TO THE SOUTHEAST COUNTIES SEEING SOME LINGERING POPS INTO EARLY SUNDAY MORNING. ATTENTION THEN TURNS TO PRECIP TYPE AND TIMING...BOTH OF WHICH WILL BE TRICKY. ALL OF THE PRECIP OVER CENTRAL INDIANA WILL BE IN THE FORM OF RAIN THROUGH THIS EVENING. COLDER AIR WILL BEGIN WORKING INTO THE NORTHWEST COUNTIES OF THE CWA ABOUT MIDNIGHT AND PUSH TOWARD THE I-70 CORRIDOR BY 2-3 AM. BEST CHANCE IN TERMS OF PRECIP TYPE ARE STILL A -RA/SN MIX...CANNOT RULE OUT ANY SLEET MIXING IN AT TIMES HOWEVER NOT WIDESPREAD ENOUGH TO HAVE THE CONFIDENCE TO INCLUDE IT IN FORECAST AT THIS TIME. THIS MIX WILL WORK IT/S WAY TOWARD THE E/SE EARLY SUNDAY MORNING...WHILE PRECIP BEHIND IT BEGINS TO WIND DOWN AND DRY OUT OVER MOST OF THE FORECAST AREA BY 12Z SUNDAY MORNING. LOWS 31-36. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... ISSUED AT 324 PM EST SAT DEC 27 2014 AS MENTIONED IN ABOVE DISCUSSION...THERE WILL LIKELY BE SOME REMNANT MIXTURE OF -RA/SN FOR EARLY SUNDAY MORNING ACROSS SEVERAL OF THE SOUTHEASTERN COUNTIES BEFORE THAT FRONT MOVES FARTHER FROM THE AREA AND DRIER AND COLDER AIR FILTERS BACK INTO THE AREA. WILL CONTINUE LOW CHANCE POPS THERE AT LEAST THROUGH 14-15Z SUNDAY MORNING. DRY AND COOLER WEATHER WILL PERSIST ACROSS THE REGION FOR THE BETTER HALF OF THE NEXT WEEK AS A LARGE AREA OF HIGH PRESSURE REMAINS IN CONTROL OVER THE REGION. MODELS INDICATE HIGHS IN THE UPPER 30S SUNDAY AND PERHAPS A DEGREE OR TWO WARMER MONDAY. LOWS WILL BE IN THE MIDDLE TO UPPER 20S SUNDAY NIGHT AND LOWER OR MIDDLE 20S MONDAY NIGHT AS A DRY SECONDARY COLD FRONT MOVES THROUGH. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ISSUED AT 240 PM EST SAT DEC 27 2014 MAIN FOCUS FOR THE EXTENDED PERIOD WILL BE POPS AND PRECIPITATION TYPE STARTING FRIDAY. PRIOR TO THAT...TEMPERATURES WILL BE THE BIGGEST ISSUE AS STRONG COLD WESTERN CANADIAN HIGH PRESSURE WILL SETTLE ACROSS THE OHIO VALLEY TO END THE OLD YEAR AND START THE NEW ONE. DETERMINISTIC MODELS ARE IN DECENT AGREEMENT THAT AN UPPER LOW WILL BE OVER NORTHEASTERN ARIZONA DURING THE EVENING OF THE FIRST DAY OF 2015. HOWEVER...THE MODELS THEN DIVERGE RAPIDLY WITH THE MUCH QUICKER 12Z GFS BRINGING A STRONGER SURFACE SYSTEM BUT WEAK UPPER WAVE OVER THE OHIO VALLEY FRIDAY NIGHT. MEANWHILE...THE 12Z ECMWF HAS EVEN A WEAKER BUT MUCH SLOWER WAVE LIFT NORTHEAST TO SOUTHERN ILLINOIS BY NEXT SATURDAY EVENING. THE EURO ALSO HAS THE MAIN SURFACE LOW WELL SOUTHWEST OF THE 12Z GFS POSITION SATURDAY EVENING. THE ECMWF HAS THE SURFACE LOW OVER EASTERN KENTUCKY...WHILE THE GFS HAS IT OVER SOUTHERN QUEBEC. DESPITE ALL THESE DIFFERENCES...BOTH MODELS START THE QPF ON FRIDAY WITH THE HEAVIEST PRECIPITATION ALONG THE OHIO RIVER. MEANWHILE...THE EURO WAS HOLDING MORE QPF AROUND ON SUNDAY THAN THE GFS. SO...STILL EXPECT THE PRECIPITATION TO SPREAD NORTHEAST ACROSS THE AREA ON FRIDAY. WITH CONFIDENCE IN TIMING LOW...WILL ACCEPT THE REGIONAL BLEND THAT KEEPS DECENT POPS AROUND NEXT SATURDAY AS HINTED AT BY THE EURO. REGARDING PRECIPITATION TYPE...WILL NOT MAKE MANY CHANGES WITH THE MODEL DIFFERENCES. CONFIDENCE NOT GOOD AS TO WHERE THE RAIN/SNOW LINE WILL BE IN SPACE AND TIME. HOWEVER...NORTHEASTERN PARTS OF THE FORECAST AREA WILL BE MORE LIKELY TO SEE FROZEN OR MIXED PRECIPITATION THEN THE SOUTHWESTERN ONES ON FRIDAY BASED ON THERMAL PROFILES FROM BUFKIT SOUNDINGS AS WELL AS PARTIAL THICKNESSES. FRIDAY NIGHT AND SATURDAY...THE NORTHWESTERN COUNTIES WOULD HAVE A HIGHER CHANCE OF MIXED OR FROZEN PRECIPITATION THAN THE SOUTHEAST AS COLDER AIR MOVES IN FROM THE NORTHWEST IN THE WAKE OF THE SURFACE SYSTEM. BUFKIT SOUNDINGS EVEN SUGGEST FREEZING RAIN OR SLEET COULD POSSIBLY MIX IN AT TIMES FRIDAY NIGHT. GENERALLY ACCEPTED THE REGIONAL BLEND TEMPERATURES. DO NOT FEEL CONFIDENT ENOUGH TO MAKE CHANGES UNTIL THE MODELS HOPEFULLY COME CLOSER TOGETHER IN SUBSEQUENT RUNS. AFTERNOON HIGHS IN THE 20S LOOK GOOD ON NEW YEAR`S DAY WITH HIGHS MOSTLY IN THE 30S THEREAFTER. MEANWHILE...NEW YEARS EVE NIGHT SHOULD BE THE COLDEST WITH OVERNIGHT LOWS IN THE TEENS FOR THE FIRST SUNRISE OF THE YEAR. OVERNIGHT LOWS WILL MOSTLY BE IN THE 20S AND 30S BY LATE WEEK. && .AVIATION /DISCUSSION FOR THE 28/0600Z TAF ISSUANCE/... ISSUED AT 1211 AM EST SUN DEC 28 2014 WINDS TO REMAIN BELOW 10 KNOTS THROUGH THE FORECAST. RAIN HAS ENDED AT ALL TAF SITES EXCEPT KBMG BUT SHOULD ALSO END THERE WITHIN THE HOUR OR AROUND 280700Z. WITHIN COLD AND DRY AIR ADVECTING IN...VISIBILITY HAS IMPROVED TO 6+ MILES AND WILL REMAIN THAT WAY THROUGH THE FORECAST. MULTIPLE CLOUD LAYERS HAVE BEEN OBSERVED ACROSS ILLINOIS BUT SEEM TO BE SETTLING TOWARDS DECKS OF 1800-2200 FEET AND THESE SHOULD PREVAIL THROUGH THE MORNING. AS HIGH PRESSURE CONTINUES BUILDING IN AND SUBSIDENCE BEGINS TO DRY THIS LOWER LAYER EXPECT BREAKS IN THE 2000 FOOT DECK AROUND 281800Z AND EVENTUAL CLEARING OF ALL CLOUDS BY 290000Z. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...SMF NEAR TERM...SMF/NIELD SHORT TERM...SMF LONG TERM...MK AVIATION...DT VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS JACKSON KY
157 PM EST SUN DEC 28 2014 .UPDATE... ISSUED AT 157 PM EST SUN DEC 28 2014 THE CONTINUOUS RAINFALL CONTINUES TO STREAM NORTHEAST FROM THE SOUTH. THE COLD FRONT THAT HAS PASSED THROUGH MUCH OF EASTERN KENTUCKY HAS NEARLY STALLED OVER THE FAR EASTERN COUNTIES OF EAST KENTUCKY. CURRENT TRENDS IN RADAR MOSAIC AND OBSERVATIONS ARE BEGINNING TO SHOW A GRADUAL EASTWARD TREND NOW AND MUCH OF THE BLUEGRASS AREA WILL SEE RAIN TAPERING OFF A BIT. HAVE ADJUSTED THE FORECAST FOR THIS AND THE GRADUAL EAST TO SOUTHEAST MOVEMENT OF THE RAINFALL. THE GENERAL CONCERN RIGHT NOW IS THE EVER SO SLOWLY DROPPING TEMPERATURES FROM THE NORTHWEST TO SOUTHEAST. AT THIS POINT...THIS IS NOT EXPECTED TO RESULT IN FROZEN PRECIP ACROSS THE BLUEGRASS BUT MAY RESULT IN A CHANGE OVER IN THE HIGHER ELEVATIONS TO THE EAST TOMORROW NIGHT. A NEW ZFP HAS BEEN ISSUED FOR THIS UPDATE. UPDATE ISSUED AT 1042 AM EST SUN DEC 28 2014 CONDITIONS ACROSS THE AREA THIS MORNING FEATURE THE LARGE AREA OF RAIN MOVING THROUGH EASTERN KENTUCKY. THE COLD FRONT NOW POSITIONED IN FAR EASTERN KENTUCKY HAS SLOWED WITH A LARGE INFLUX OF MOISTURE AHEAD AND BEHIND OF THIS FRONT IN THE FORM OF LIGHT TO MODERATE RAINFALL. UPSTREAM...SOUTH INTO THE TN VALLEY AND SOUTHWEST INTO THE MS VALLEY...MOISTURE CONTINUES TO STREAM NORTHWARD INTO THE AREA. WILL EXPECT THE CHANCE OF RAIN TO CONTINUE THROUGH THE REST OF THE DAY...SOME MODERATE TO HEAVY RAINFALL IS ALSO POSSIBLE. THIS CURRENT TREND OF THINKING IS ALONG WITH THE CURRENT FORECAST AND WILL ALLOW THE CURRENT ZFP TO RIDE THROUGH THE MORNING. TEMPERATURES WILL REMAIN MAINLY STEADY SO HAVE UPDATED THE GRIDS WITH THE CURRENT OBS AND SENT THE GRIDS TOT HE NDFD SERVERS. UPDATE ISSUED AT 720 AM EST SUN DEC 28 2014 SLOW MOVING COLD FRONT CONTINUES TO PUSH INTO THE AREA WITH RAIN AND DRIZZLE ALONG AND AHEAD OF THE BOUNDARY. THE MAIN BAND OF RAIN AND DRIZZLE ASSOCIATED WITH THE FRONT CONTINUES TO DRIFT SOUTHEASTWARD AS WELL. UPDATE CHALLENGE CENTERS AROUND THE POTENTIAL FOR A SECOND ROUND OF RAIN A BIT LATER TODAY. NAM IS MORE PROGRESSIVE IN TAKING ALL THIS ACTIVITY TO OUR EAST THAN THE GFS AND ECMWF...WHICH SEEM TO HANG ON TO THE IDEA OF A SECOND WAVE TRACKING TO OUR SOUTHEAST WITH RAIN LINGERING ACROSS A GOOD PORTION OF THE AREA...MAINLY OUR SOUTHEAST. THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE CURRENT SITUATION AND BRINGS ANOTHER ROUND OF PRECIPITATION OVER MOST IF NOT ALL OF OUR FORECAST AREA BY MID MORNING. REGIONAL COMPOSITE RADAR TENDS TO SUPPORT THE HRRR AS ECHOS ARE FILLING IN AND INTENSIFYING ACROSS WESTERN TENNESSEE AND MOVING QUICKLY TO THE NORTHEAST. UPDATE WILL ENTAIL ONLY MINOR TWEAKS TO THE POP GRIDS FOR RECENT RADAR TRENDS AND AN UPDATE TO THE GRIDS FOR LATEST HOURLY OBSERVATIONS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 MODELS ARE IN FAIRLY GOOD AGREEMENT FOR THE SHORT TERM. ENERGY FROM PLAINS MID/UPPER LEVEL TROUGH WILL PASS WEST TO EAST ACROSS THE OHIO VALLEY...WITH CORRESPONDING SFC LOW OVER NEW ENGLAND DRAGGING A SFC COLD FRONT THROUGH THE REGION. THIS COLD FRONT IS MOVING THROUGH THE OHIO VALLEY THIS MORNING...ROUGHLY STRETCHING FROM EAST CENTRAL OHIO SOUTHWEST TO WESTERN TN...HAVING PASSED THOUGH CVG AND BWG. THE FRONT WILL BE MOVING THROUGH EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS WITH DRIZZLE AND LIGHT RAIN BEING PRODUCED ALONG AND AHEAD OF THE BOUNDARY. THIS FEATURE WILL CARRY PRECIP EASTWARD WITH IT THROUGH THE MORNING...RESULTING IN A POSSIBLE LULL IN RAIN FOR A PERIOD OF TIME. BUT LOW PRESSURE CURRENTLY DEVELOPING OVER SOUTH CENTRAL MISSISSIPPI WILL MOVE NORTHEAST INTO THE SOUTHERN APPALACHIANS THROUGH THE DAY...RESULTING IN ANOTHER ROUND OF RAINFALL...PARTICULARLY FOR THE SOUTHEASTERN HALF OF OUR FORECAST AREA. RAIN SHOWERS WILL LINGER ACROSS PORTIONS OF THE AREA TONIGHT BEFORE TAPERING OFF THROUGH THE DAY MONDAY. COOLER AIR BEHIND THE FRONT WILL BRING OUR TEMPERATURES BACK DOWN TO NORMAL LEVELS THROUGH THE PERIOD. RAINFALL AMOUNTS HAVE BEEN RATHER LIGHT OVERALL...AROUND A THIRD OF AN INCH IN OUR SOUTHERN MOST COUNTIES THUS FAR AND MUCH SMALLER AMOUNTS ELSEWHERE. EXPECT TO SEE ABOUT THE SAME AMOUNT OR LESS ACROSS THE AREA TODAY AND TONIGHT. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 PERIOD WILL BEGIN WITH SLIGHT CHANCE OF PRECIP LINGERING ACROSS THE SE PORTIONS OF THE CWA...HOWEVER THESE CHANCES WILL DROP AS WE MOVE INTO TUESDAY AS HIGH PRESSURE BUILDS EAST. THE PREVIOUS NAM DID TRY TO BRING MORE PRECIP ACROSS THE REGION BUT THE 06Z RUN BACKED OFF ON THIS ONCE AGAIN. THIS HIGH PRESSURE WILL CONTINUE TO USHER IN A COLDER AIR MASS AND WILL KEEP WEATHER QUIET THROUGH WEDNESDAY NIGHT. THIS COLDER AIR MASS WILL LEAD TO HIGHS IN THE LOW TO MID 30S FOR WEDNESDAY AND LOWS WEDNESDAY NIGHT IN THE UPPER TEENS TO LOWER 20S. THIS SURFACE HIGH WILL BEGIN SHIFTING TO THE EAST AND WE WILL BEGIN TO SEE SOME RETURN FLOW AS WE MOVE INTO THURSDAY. THIS WILL ALLOW HIGHS TO RETURN TO THE UPPER 30S AND LOWER 40S. THEN WE START TO FOCUS ON ANOTHER SYSTEM DEVELOPING ACROSS THE SOUTHERN PLAINS. THURSDAY NIGHT A CLOSED LOW WILL BE CENTERED ACROSS THE FOUR CORNER REGION. THIS UPPER LEVEL LOW WILL BEGIN EJECTING EAST AND WILL AID IN DEVELOPING A LOW PRESSURE SYSTEM ACROSS THE SOUTHERN PLAINS. CLOUDS WILL CONTINUE TO INCREASE ACROSS THE REGION THURSDAY NIGHT AHEAD OF THIS SYSTEM. THIS SURFACE LOW IS EXPECTED TO MOVE NORTHEAST OUT OF THE ARKLATEX AND INTO THE GREAT LAKES REGION BY SATURDAY. INITIAL ONSET OF PRECIP MAINLY THURSDAY NIGHT COULD BRING SNOW TO RAIN/SNOW MIX...HOWEVER AS WARM FRONT MOVES NORTH AND EASTERN KY GETS IN THE WARM SECTOR WE WILL SEE A CHANGE TO ALL RAIN FRIDAY. TRAILING COLD FRONT WILL MOVE ACROSS THE REGION GOING INTO SATURDAY. MODELS ALSO INDICATE THIS SYSTEM WILL LEAD TO A SUBSTANTIAL LOW LEVEL JET ACROSS THE REGION MAKING FOR A WINDY DAY ACROSS EASTERN KY. THESE WINDS WILL LIKELY GUST HIGHEST WITH SHOWER ACTIVITY ALONG AND NEAR THE COLD FRONT ALLOWING FOR MAXIMUM MIXING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1227 PM EST SUN DEC 28 2014 A COLD FRONT MOVING THROUGH THE AREA AND CONTINUOUS STREAMING MOISTURE UP FROM THE SOUTHWEST THROUGH THIS EVENING AND TONIGHT WILL RESULT IN AN EXTENDED PERIOD OF RAINFALL. THIS WILL CONTINUE TO PRODUCE IFR CEILINGS AND MANY LOCATIONS BELOW FIELD MINS AT MANY OF THE TAF SITES. THIS IS EXPECTED TO CONTINUE THROUGH MUCH OF THE TAF PERIOD. RAIN AND FOG WILL HINDER VISIBILITY AS WELL WITH TAF SITES HAVING VARYING VALUES THROUGH THE NIGHT. WINDS WILL BE LIGHT THROUGH THE PERIOD WITH CONDITIONS IMPROVING SLIGHTLY BY THE END OF THE TAF PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SHALLENBERGER SHORT TERM...RAY LONG TERM...DJ AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
1227 PM EST SUN DEC 28 2014 .UPDATE... ISSUED AT 1042 AM EST SUN DEC 28 2014 CONDITIONS ACROSS THE AREA THIS MORNING FEATURE THE LARGE AREA OF RAIN MOVING THROUGH EASTERN KENTUCKY. THE COLD FRONT NOW POSITIONED IN FAR EASTERN KENTUCKY HAS SLOWED WITH A LARGE INFLUX OF MOISTURE AHEAD AND BEHIND OF THIS FRONT IN THE FORM OF LIGHT TO MODERATE RAINFALL. UPSTREAM...SOUTH INTO THE TN VALLEY AND SOUTHWEST INTO THE MS VALLEY...MOISTURE CONTINUES TO STREAM NORTHWARD INTO THE AREA. WILL EXPECT THE CHANCE OF RAIN TO CONTINUE THROUGH THE REST OF THE DAY...SOME MODERATE TO HEAVY RAINFALL IS ALSO POSSIBLE. THIS CURRENT TREND OF THINKING IS ALONG WITH THE CURRENT FORECAST AND WILL ALLOW THE CURRENT ZFP TO RIDE THROUGH THE MORNING. TEMPERATURES WILL REMAIN MAINLY STEADY SO HAVE UPDATED THE GRIDS WITH THE CURRENT OBS AND SENT THE GRIDS TOT HE NDFD SERVERS. UPDATE ISSUED AT 720 AM EST SUN DEC 28 2014 SLOW MOVING COLD FRONT CONTINUES TO PUSH INTO THE AREA WITH RAIN AND DRIZZLE ALONG AND AHEAD OF THE BOUNDARY. THE MAIN BAND OF RAIN AND DRIZZLE ASSOCIATED WITH THE FRONT CONTINUES TO DRIFT SOUTHEASTWARD AS WELL. UPDATE CHALLENGE CENTERS AROUND THE POTENTIAL FOR A SECOND ROUND OF RAIN A BIT LATER TODAY. NAM IS MORE PROGRESSIVE IN TAKING ALL THIS ACTIVITY TO OUR EAST THAN THE GFS AND ECMWF...WHICH SEEM TO HANG ON TO THE IDEA OF A SECOND WAVE TRACKING TO OUR SOUTHEAST WITH RAIN LINGERING ACROSS A GOOD PORTION OF THE AREA...MAINLY OUR SOUTHEAST. THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE CURRENT SITUATION AND BRINGS ANOTHER ROUND OF PRECIPITATION OVER MOST IF NOT ALL OF OUR FORECAST AREA BY MID MORNING. REGIONAL COMPOSITE RADAR TENDS TO SUPPORT THE HRRR AS ECHOS ARE FILLING IN AND INTENSIFYING ACROSS WESTERN TENNESSEE AND MOVING QUICKLY TO THE NORTHEAST. UPDATE WILL ENTAIL ONLY MINOR TWEAKS TO THE POP GRIDS FOR RECENT RADAR TRENDS AND AN UPDATE TO THE GRIDS FOR LATEST HOURLY OBSERVATIONS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 MODELS ARE IN FAIRLY GOOD AGREEMENT FOR THE SHORT TERM. ENERGY FROM PLAINS MID/UPPER LEVEL TROUGH WILL PASS WEST TO EAST ACROSS THE OHIO VALLEY...WITH CORRESPONDING SFC LOW OVER NEW ENGLAND DRAGGING A SFC COLD FRONT THROUGH THE REGION. THIS COLD FRONT IS MOVING THROUGH THE OHIO VALLEY THIS MORNING...ROUGHLY STRETCHING FROM EAST CENTRAL OHIO SOUTHWEST TO WESTERN TN...HAVING PASSED THOUGH CVG AND BWG. THE FRONT WILL BE MOVING THROUGH EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS WITH DRIZZLE AND LIGHT RAIN BEING PRODUCED ALONG AND AHEAD OF THE BOUNDARY. THIS FEATURE WILL CARRY PRECIP EASTWARD WITH IT THROUGH THE MORNING...RESULTING IN A POSSIBLE LULL IN RAIN FOR A PERIOD OF TIME. BUT LOW PRESSURE CURRENTLY DEVELOPING OVER SOUTH CENTRAL MISSISSIPPI WILL MOVE NORTHEAST INTO THE SOUTHERN APPALACHIANS THROUGH THE DAY...RESULTING IN ANOTHER ROUND OF RAINFALL...PARTICULARLY FOR THE SOUTHEASTERN HALF OF OUR FORECAST AREA. RAIN SHOWERS WILL LINGER ACROSS PORTIONS OF THE AREA TONIGHT BEFORE TAPERING OFF THROUGH THE DAY MONDAY. COOLER AIR BEHIND THE FRONT WILL BRING OUR TEMPERATURES BACK DOWN TO NORMAL LEVELS THROUGH THE PERIOD. RAINFALL AMOUNTS HAVE BEEN RATHER LIGHT OVERALL...AROUND A THIRD OF AN INCH IN OUR SOUTHERN MOST COUNTIES THUS FAR AND MUCH SMALLER AMOUNTS ELSEWHERE. EXPECT TO SEE ABOUT THE SAME AMOUNT OR LESS ACROSS THE AREA TODAY AND TONIGHT. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 PERIOD WILL BEGIN WITH SLIGHT CHANCE OF PRECIP LINGERING ACROSS THE SE PORTIONS OF THE CWA...HOWEVER THESE CHANCES WILL DROP AS WE MOVE INTO TUESDAY AS HIGH PRESSURE BUILDS EAST. THE PREVIOUS NAM DID TRY TO BRING MORE PRECIP ACROSS THE REGION BUT THE 06Z RUN BACKED OFF ON THIS ONCE AGAIN. THIS HIGH PRESSURE WILL CONTINUE TO USHER IN A COLDER AIR MASS AND WILL KEEP WEATHER QUIET THROUGH WEDNESDAY NIGHT. THIS COLDER AIR MASS WILL LEAD TO HIGHS IN THE LOW TO MID 30S FOR WEDNESDAY AND LOWS WEDNESDAY NIGHT IN THE UPPER TEENS TO LOWER 20S. THIS SURFACE HIGH WILL BEGIN SHIFTING TO THE EAST AND WE WILL BEGIN TO SEE SOME RETURN FLOW AS WE MOVE INTO THURSDAY. THIS WILL ALLOW HIGHS TO RETURN TO THE UPPER 30S AND LOWER 40S. THEN WE START TO FOCUS ON ANOTHER SYSTEM DEVELOPING ACROSS THE SOUTHERN PLAINS. THURSDAY NIGHT A CLOSED LOW WILL BE CENTERED ACROSS THE FOUR CORNER REGION. THIS UPPER LEVEL LOW WILL BEGIN EJECTING EAST AND WILL AID IN DEVELOPING A LOW PRESSURE SYSTEM ACROSS THE SOUTHERN PLAINS. CLOUDS WILL CONTINUE TO INCREASE ACROSS THE REGION THURSDAY NIGHT AHEAD OF THIS SYSTEM. THIS SURFACE LOW IS EXPECTED TO MOVE NORTHEAST OUT OF THE ARKLATEX AND INTO THE GREAT LAKES REGION BY SATURDAY. INITIAL ONSET OF PRECIP MAINLY THURSDAY NIGHT COULD BRING SNOW TO RAIN/SNOW MIX...HOWEVER AS WARM FRONT MOVES NORTH AND EASTERN KY GETS IN THE WARM SECTOR WE WILL SEE A CHANGE TO ALL RAIN FRIDAY. TRAILING COLD FRONT WILL MOVE ACROSS THE REGION GOING INTO SATURDAY. MODELS ALSO INDICATE THIS SYSTEM WILL LEAD TO A SUBSTANTIAL LOW LEVEL JET ACROSS THE REGION MAKING FOR A WINDY DAY ACROSS EASTERN KY. THESE WINDS WILL LIKELY GUST HIGHEST WITH SHOWER ACTIVITY ALONG AND NEAR THE COLD FRONT ALLOWING FOR MAXIMUM MIXING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1227 PM EST SUN DEC 28 2014 A COLD FRONT MOVING THROUGH THE AREA AND CONTINUOUS STREAMING MOISTURE UP FROM THE SOUTHWEST THROUGH THIS EVENING AND TONIGHT WILL RESULT IN AN EXTENDED PERIOD OF RAINFALL. THIS WILL CONTINUE TO PRODUCE IFR CEILINGS AND MANY LOCATIONS BELOW FIELD MINS AT MANY OF THE TAF SITES. THIS IS EXPECTED TO CONTINUE THROUGH MUCH OF THE TAF PERIOD. RAIN AND FOG WILL HINDER VISIBILITY AS WELL WITH TAF SITES HAVING VARYING VALUES THROUGH THE NIGHT. WINDS WILL BE LIGHT THROUGH THE PERIOD WITH CONDITIONS IMPROVING SLIGHTLY BY THE END OF THE TAF PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SHALLENBERGER SHORT TERM...RAY LONG TERM...DJ AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS JACKSON KY
1042 AM EST SUN DEC 28 2014 .UPDATE... ISSUED AT 1042 AM EST SUN DEC 28 2014 CONDITIONS ACROSS THE AREA THIS MORNING FEATURE THE LARGE AREA OF RAIN MOVING THROUGH EASTERN KENTUCKY. THE COLD FRONT NOW POSITIONED IN FAR EASTERN KENTUCKY HAS SLOWED WITH A LARGE INFLUX OF MOISTURE AHEAD AND BEHIND OF THIS FRONT IN THE FORM OF LIGHT TO MODERATE RAINFALL. UPSTREAM...SOUTH INTO THE TN VALLEY AND SOUTHWEST INTO THE MS VALLEY...MOISTURE CONTINUES TO STREAM NORTHWARD INTO THE AREA. WILL EXPECT THE CHANCE OF RAIN TO CONTINUE THROUGH THE REST OF THE DAY...SOME MODERATE TO HEAVY RAINFALL IS ALSO POSSIBLE. THIS CURRENT TREND OF THINKING IS ALONG WITH THE CURRENT FORECAST AND WILL ALLOW THE CURRENT ZFP TO RIDE THROUGH THE MORNING. TEMPERATURES WILL REMAIN MAINLY STEADY SO HAVE UPDATED THE GRIDS WITH THE CURRENT OBS AND SENT THE GRIDS TOT HE NDFD SERVERS. UPDATE ISSUED AT 720 AM EST SUN DEC 28 2014 SLOW MOVING COLD FRONT CONTINUES TO PUSH INTO THE AREA WITH RAIN AND DRIZZLE ALONG AND AHEAD OF THE BOUNDARY. THE MAIN BAND OF RAIN AND DRIZZLE ASSOCIATED WITH THE FRONT CONTINUES TO DRIFT SOUTHEASTWARD AS WELL. UPDATE CHALLENGE CENTERS AROUND THE POTENTIAL FOR A SECOND ROUND OF RAIN A BIT LATER TODAY. NAM IS MORE PROGRESSIVE IN TAKING ALL THIS ACTIVITY TO OUR EAST THAN THE GFS AND ECMWF...WHICH SEEM TO HANG ON TO THE IDEA OF A SECOND WAVE TRACKING TO OUR SOUTHEAST WITH RAIN LINGERING ACROSS A GOOD PORTION OF THE AREA...MAINLY OUR SOUTHEAST. THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE CURRENT SITUATION AND BRINGS ANOTHER ROUND OF PRECIPITATION OVER MOST IF NOT ALL OF OUR FORECAST AREA BY MID MORNING. REGIONAL COMPOSITE RADAR TENDS TO SUPPORT THE HRRR AS ECHOS ARE FILLING IN AND INTENSIFYING ACROSS WESTERN TENNESSEE AND MOVING QUICKLY TO THE NORTHEAST. UPDATE WILL ENTAIL ONLY MINOR TWEAKS TO THE POP GRIDS FOR RECENT RADAR TRENDS AND AN UPDATE TO THE GRIDS FOR LATEST HOURLY OBSERVATIONS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 MODELS ARE IN FAIRLY GOOD AGREEMENT FOR THE SHORT TERM. ENERGY FROM PLAINS MID/UPPER LEVEL TROUGH WILL PASS WEST TO EAST ACROSS THE OHIO VALLEY...WITH CORRESPONDING SFC LOW OVER NEW ENGLAND DRAGGING A SFC COLD FRONT THROUGH THE REGION. THIS COLD FRONT IS MOVING THROUGH THE OHIO VALLEY THIS MORNING...ROUGHLY STRETCHING FROM EAST CENTRAL OHIO SOUTHWEST TO WESTERN TN...HAVING PASSED THOUGH CVG AND BWG. THE FRONT WILL BE MOVING THROUGH EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS WITH DRIZZLE AND LIGHT RAIN BEING PRODUCED ALONG AND AHEAD OF THE BOUNDARY. THIS FEATURE WILL CARRY PRECIP EASTWARD WITH IT THROUGH THE MORNING...RESULTING IN A POSSIBLE LULL IN RAIN FOR A PERIOD OF TIME. BUT LOW PRESSURE CURRENTLY DEVELOPING OVER SOUTH CENTRAL MISSISSIPPI WILL MOVE NORTHEAST INTO THE SOUTHERN APPALACHIANS THROUGH THE DAY...RESULTING IN ANOTHER ROUND OF RAINFALL...PARTICULARLY FOR THE SOUTHEASTERN HALF OF OUR FORECAST AREA. RAIN SHOWERS WILL LINGER ACROSS PORTIONS OF THE AREA TONIGHT BEFORE TAPERING OFF THROUGH THE DAY MONDAY. COOLER AIR BEHIND THE FRONT WILL BRING OUR TEMPERATURES BACK DOWN TO NORMAL LEVELS THROUGH THE PERIOD. RAINFALL AMOUNTS HAVE BEEN RATHER LIGHT OVERALL...AROUND A THIRD OF AN INCH IN OUR SOUTHERN MOST COUNTIES THUS FAR AND MUCH SMALLER AMOUNTS ELSEWHERE. EXPECT TO SEE ABOUT THE SAME AMOUNT OR LESS ACROSS THE AREA TODAY AND TONIGHT. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 PERIOD WILL BEGIN WITH SLIGHT CHANCE OF PRECIP LINGERING ACROSS THE SE PORTIONS OF THE CWA...HOWEVER THESE CHANCES WILL DROP AS WE MOVE INTO TUESDAY AS HIGH PRESSURE BUILDS EAST. THE PREVIOUS NAM DID TRY TO BRING MORE PRECIP ACROSS THE REGION BUT THE 06Z RUN BACKED OFF ON THIS ONCE AGAIN. THIS HIGH PRESSURE WILL CONTINUE TO USHER IN A COLDER AIR MASS AND WILL KEEP WEATHER QUIET THROUGH WEDNESDAY NIGHT. THIS COLDER AIR MASS WILL LEAD TO HIGHS IN THE LOW TO MID 30S FOR WEDNESDAY AND LOWS WEDNESDAY NIGHT IN THE UPPER TEENS TO LOWER 20S. THIS SURFACE HIGH WILL BEGIN SHIFTING TO THE EAST AND WE WILL BEGIN TO SEE SOME RETURN FLOW AS WE MOVE INTO THURSDAY. THIS WILL ALLOW HIGHS TO RETURN TO THE UPPER 30S AND LOWER 40S. THEN WE START TO FOCUS ON ANOTHER SYSTEM DEVELOPING ACROSS THE SOUTHERN PLAINS. THURSDAY NIGHT A CLOSED LOW WILL BE CENTERED ACROSS THE FOUR CORNER REGION. THIS UPPER LEVEL LOW WILL BEGIN EJECTING EAST AND WILL AID IN DEVELOPING A LOW PRESSURE SYSTEM ACROSS THE SOUTHERN PLAINS. CLOUDS WILL CONTINUE TO INCREASE ACROSS THE REGION THURSDAY NIGHT AHEAD OF THIS SYSTEM. THIS SURFACE LOW IS EXPECTED TO MOVE NORTHEAST OUT OF THE ARKLATEX AND INTO THE GREAT LAKES REGION BY SATURDAY. INITIAL ONSET OF PRECIP MAINLY THURSDAY NIGHT COULD BRING SNOW TO RAIN/SNOW MIX...HOWEVER AS WARM FRONT MOVES NORTH AND EASTERN KY GETS IN THE WARM SECTOR WE WILL SEE A CHANGE TO ALL RAIN FRIDAY. TRAILING COLD FRONT WILL MOVE ACROSS THE REGION GOING INTO SATURDAY. MODELS ALSO INDICATE THIS SYSTEM WILL LEAD TO A SUBSTANTIAL LOW LEVEL JET ACROSS THE REGION MAKING FOR A WINDY DAY ACROSS EASTERN KY. THESE WINDS WILL LIKELY GUST HIGHEST WITH SHOWER ACTIVITY ALONG AND NEAR THE COLD FRONT ALLOWING FOR MAXIMUM MIXING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 720 AM EST SUN DEC 28 2014 COLD FRONT MOVING THROUGH THE AREA THIS MORNING WILL KEEP FLIGHT CONDITIONS QUITE LOW. MODEL GUIDANCE...INITIALLY VERY SLOW TO PICK UP ON THE WORSENING WEATHER HAS FINALLY COME IN LINE WITH ACTUAL CONDITIONS THIS MORNING. AND FROM ALL APPEARANCES WE WILL SEE RAIN LINGER ACROSS MOST IF NOT ALL OF OUR AREA THROUGH THE DAY. CONSEQUENTLY FOLLOWED GUIDANCE CLOSELY WHICH WAS VERY PESSIMISTIC... WITH IFR/LIFR CONDITIONS EXPECTED FOR MOST OF THE FORECAST WINDOW. WINDS ARE...AND WILL CONTINUE TO VEER MORE NORTHERLY WITH TIME AT AROUND 5 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...SHALLENBERGER SHORT TERM...RAY LONG TERM...DJ AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
720 AM EST SUN DEC 28 2014 .UPDATE... ISSUED AT 720 AM EST SUN DEC 28 2014 SLOW MOVING COLD FRONT CONTINUES TO PUSH INTO THE AREA WITH RAIN AND DRIZZLE ALONG AND AHEAD OF THE BOUNDARY. THE MAIN BAND OF RAIN AND DRIZZLE ASSOCIATED WITH THE FRONT CONTINUES TO DRIFT SOUTHEASTWARD AS WELL. UPDATE CHALLENGE CENTERS AROUND THE POTENTIAL FOR A SECOND ROUND OF RAIN A BIT LATER TODAY. NAM IS MORE PROGRESSIVE IN TAKING ALL THIS ACTIVITY TO OUR EAST THAN THE GFS AND ECMWF...WHICH SEEM TO HANG ON TO THE IDEA OF A SECOND WAVE TRACKING TO OUR SOUTHEAST WITH RAIN LINGERING ACROSS A GOOD PORTION OF THE AREA...MAINLY OUR SOUTHEAST. THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE CURRENT SITUATION AND BRINGS ANOTHER ROUND OF PRECIPITATION OVER MOST IF NOT ALL OF OUR FORECAST AREA BY MID MORNING. REGIONAL COMPOSITE RADAR TENDS TO SUPPORT THE HRRR AS ECHOS ARE FILLING IN AND INTENSIFYING ACROSS WESTERN TENNESSEE AND MOVING QUICKLY TO THE NORTHEAST. UPDATE WILL ENTAIL ONLY MINOR TWEAKS TO THE POP GRIDS FOR RECENT RADAR TRENDS AND AN UPDATE TO THE GRIDS FOR LATEST HOURLY OBSERVATIONS. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 MODELS ARE IN FAIRLY GOOD AGREEMENT FOR THE SHORT TERM. ENERGY FROM PLAINS MID/UPPER LEVEL TROUGH WILL PASS WEST TO EAST ACROSS THE OHIO VALLEY...WITH CORRESPONDING SFC LOW OVER NEW ENGLAND DRAGGING A SFC COLD FRONT THROUGH THE REGION. THIS COLD FRONT IS MOVING THROUGH THE OHIO VALLEY THIS MORNING...ROUGHLY STRETCHING FROM EAST CENTRAL OHIO SOUTHWEST TO WESTERN TN...HAVING PASSED THOUGH CVG AND BWG. THE FRONT WILL BE MOVING THROUGH EASTERN KENTUCKY OVER THE NEXT SEVERAL HOURS WITH DRIZZLE AND LIGHT RAIN BEING PRODUCED ALONG AND AHEAD OF THE BOUNDARY. THIS FEATURE WILL CARRY PRECIP EASTWARD WITH IT THROUGH THE MORNING...RESULTING IN A POSSIBLE LULL IN RAIN FOR A PERIOD OF TIME. BUT LOW PRESSURE CURRENTLY DEVELOPING OVER SOUTH CENTRAL MISSISSIPPI WILL MOVE NORTHEAST INTO THE SOUTHERN APPALACHIANS THROUGH THE DAY...RESULTING IN ANOTHER ROUND OF RAINFALL...PARTICULARLY FOR THE SOUTHEASTERN HALF OF OUR FORECAST AREA. RAIN SHOWERS WILL LINGER ACROSS PORTIONS OF THE AREA TONIGHT BEFORE TAPERING OFF THROUGH THE DAY MONDAY. COOLER AIR BEHIND THE FRONT WILL BRING OUR TEMPERATURES BACK DOWN TO NORMAL LEVELS THROUGH THE PERIOD. RAINFALL AMOUNTS HAVE BEEN RATHER LIGHT OVERALL...AROUND A THIRD OF AN INCH IN OUR SOUTHERN MOST COUNTIES THUS FAR AND MUCH SMALLER AMOUNTS ELSEWHERE. EXPECT TO SEE ABOUT THE SAME AMOUNT OR LESS ACROSS THE AREA TODAY AND TONIGHT. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 425 AM EST SUN DEC 28 2014 PERIOD WILL BEGIN WITH SLIGHT CHANCE OF PRECIP LINGERING ACROSS THE SE PORTIONS OF THE CWA...HOWEVER THESE CHANCES WILL DROP AS WE MOVE INTO TUESDAY AS HIGH PRESSURE BUILDS EAST. THE PREVIOUS NAM DID TRY TO BRING MORE PRECIP ACROSS THE REGION BUT THE 06Z RUN BACKED OFF ON THIS ONCE AGAIN. THIS HIGH PRESSURE WILL CONTINUE TO USHER IN A COLDER AIR MASS AND WILL KEEP WEATHER QUIET THROUGH WEDNESDAY NIGHT. THIS COLDER AIR MASS WILL LEAD TO HIGHS IN THE LOW TO MID 30S FOR WEDNESDAY AND LOWS WEDNESDAY NIGHT IN THE UPPER TEENS TO LOWER 20S. THIS SURFACE HIGH WILL BEGIN SHIFTING TO THE EAST AND WE WILL BEGIN TO SEE SOME RETURN FLOW AS WE MOVE INTO THURSDAY. THIS WILL ALLOW HIGHS TO RETURN TO THE UPPER 30S AND LOWER 40S. THEN WE START TO FOCUS ON ANOTHER SYSTEM DEVELOPING ACROSS THE SOUTHERN PLAINS. THURSDAY NIGHT A CLOSED LOW WILL BE CENTERED ACROSS THE FOUR CORNER REGION. THIS UPPER LEVEL LOW WILL BEGIN EJECTING EAST AND WILL AID IN DEVELOPING A LOW PRESSURE SYSTEM ACROSS THE SOUTHERN PLAINS. CLOUDS WILL CONTINUE TO INCREASE ACROSS THE REGION THURSDAY NIGHT AHEAD OF THIS SYSTEM. THIS SURFACE LOW IS EXPECTED TO MOVE NORTHEAST OUT OF THE ARKLATEX AND INTO THE GREAT LAKES REGION BY SATURDAY. INITIAL ONSET OF PRECIP MAINLY THURSDAY NIGHT COULD BRING SNOW TO RAIN/SNOW MIX...HOWEVER AS WARM FRONT MOVES NORTH AND EASTERN KY GETS IN THE WARM SECTOR WE WILL SEE A CHANGE TO ALL RAIN FRIDAY. TRAILING COLD FRONT WILL MOVE ACROSS THE REGION GOING INTO SATURDAY. MODELS ALSO INDICATE THIS SYSTEM WILL LEAD TO A SUBSTANTIAL LOW LEVEL JET ACROSS THE REGION MAKING FOR A WINDY DAY ACROSS EASTERN KY. THESE WINDS WILL LIKELY GUST HIGHEST WITH SHOWER ACTIVITY ALONG AND NEAR THE COLD FRONT ALLOWING FOR MAXIMUM MIXING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 720 AM EST SUN DEC 28 2014 COLD FRONT MOVING THROUGH THE AREA THIS MORNING WILL KEEP FLIGHT CONDITIONS QUITE LOW. MODEL GUIDANCE...INITIALLY VERY SLOW TO PICK UP ON THE WORSENING WEATHER HAS FINALLY COME IN LINE WITH ACTUAL CONDITIONS THIS MORNING. AND FROM ALL APPEARANCES WE WILL SEE RAIN LINGER ACROSS MOST IF NOT ALL OF OUR AREA THROUGH THE DAY. CONSEQUENTLY FOLLOWED GUIDANCE CLOSELY WHICH WAS VERY PESSIMISTIC... WITH IFR/LIFR CONDITIONS EXPECTED FOR MOST OF THE FORECAST WINDOW. WINDS ARE...AND WILL CONTINUE TO VEER MORE NORTHERLY WITH TIME AT AROUND 5 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...RAY LONG TERM...DJ AVIATION...RAY
AREA FORECAST DISCUSSION
NWS JACKSON KY
150 AM EST SUN DEC 28 2014 .UPDATE... ISSUED AT 150 AM EST SUN DEC 28 2014 MADE SOME MINOR TWEAKS TO THE GRIDS FOR LATEST TRENDS IN RADAR AND OBS. OVERALL NO MAJOR CHANGES TO THE FORECAST PACKAGE. LIGHT RAIN AND DRIZZLE WILL CONTINUE TO OVERSPREAD THE AREA AS A COLD FRONTAL BOUNDARY DROPS DOWN INTO OUR FORECAST AREA OVER THE NEXT SEVERAL HOURS. UPDATE ISSUED AT 1030 PM EST SAT DEC 27 2014 DID AN UPDATE TO FINE TUNE THE POPS THROUGH THE REST OF THE NIGHT...MORE IN LINE WITH THE LATEST HRRR GUIDANCE. THE HRRR SHOWED THAT THE PCPN WOULD PUSH IN MOST EFFECTIVELY FROM THE NORTHWEST DURING THE EARLY MORNING HOURS WHILE THE FAR EAST STAYS NO WORSE THAN SCATTERED FOR MUCH OF THE NIGHT. ALSO TWEAKED THE T AND TD GRIDS PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH A NEW SET OF ZONES. UPDATE ISSUED AT 750 PM EST SAT DEC 27 2014 23Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE PUSHING INTO EASTERN KENTUCKY FROM THE SOUTHWEST. THIS HAS BROUGHT AN EARLY ROUND OF SHOWERS TO THE CUMBERLAND VALLEY. THESE HAVE BEEN BATTLING THE DRY AIR IN PLACE THROUGH THE AREA...BUT HAVE BEEN ABLE TO REACH THE GROUND WITH THE HEAVIER RETURNS. THESE SHOWERS WILL CONTINUE TO MOISTEN UP THE LOWER ATMOSPHERE THIS EVENING WITH THE NEXT SURGE AFTER MIDNIGHT LIKELY TO BRING WIDESPREAD RAIN TO THE ENTIRE CWA. WITH DEW POINTS IN THE 40S...ONCE THE RAIN MOVES IN PROPERLY...LOW TEMPERATURES WILL BE CAPPED IN THE LOW TO MIDDLE 40S. HAVE UPDATED THE FORECAST TO FINE TUNE THE POP CHANCES AND INFUSE SOME OF THE LATEST NEAR TERM GUIDANCE INTO THE T AND TD GRIDS. THESE UPDATES HAVE BEEN SENT TO NDFD AND THE WEB SERVERS. A ZFP UPDATE WILL FOLLOW LATER THIS EVENING ONCE THE WIDESPREAD RAINS ARE ON OUR DOORSTEP. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 331 PM EST SAT DEC 27 2014 CURRENT CONDITIONS ACROSS THE REGION FEATURE SURFACE LOW PRESSURE STRENGTHENING AS IT MOVES NORTHEAST INTO THE GREAT LAKES REGION. MEANWHILE...A SURFACE COLD FRONT ASSOCIATED WITH THIS LOW AS OF 20Z IS PUSHING INTO WESTERN KENTUCKY WITH A SWATH OF RAIN MOVING UP FROM THE MID MS RIVER VALLEY INTO CENTRAL KENTUCKY. WIDESPREAD CLOUD COVER AND RAIN CONTINUES TO PUSH EAST BUT SURFACE HIGH PRESSURE CENTERED JUST OFF THE NC COAST IS RETREATING SLIGHTLY SLOWER THAN ANTICIPATED. HENCE SOME BREAKS IN CLOUD COVER STILL ARE PRESENT IN EASTERN KENTUCKY. THIS WILL KEEP PRECIP OUT OF THE AREA A TAD LONGER...BUT AN NEW DEVELOPING SURFACE LOW PRESSURE ALONG THE WESTERN GULF COAST AND STRENGTHENING LOW LEVEL JET WILL REINFORCE THE MOISTURE SURGE NORTHEASTWARD INTO THE TN VALLEY AND OH VALLEY BY TONIGHT AND ESPECIALLY SUNDAY. MODELS SUPPORT THIS TREND AND AS SUCH...AM QUITE CONFIDENT THAT MEASURABLE PRECIP WILL MATERIALIZE TONIGHT AND HAVE GONE WITH CATEGORICAL POPS. THE STUBBORN RIDGE OVER THE BAHAMAS REMAINS IN PLACE THROUGH THE REST OF THE WEEKEND BEFORE WEAKENING LATE MONDAY AS THE TROUGH OVER THE EASTERN CONUS LIFTS INTO THE NEW ENGLAND STATES. THROUGH THIS PERIOD THOUGH...QUITE A STRONG MOIST LOW LEVEL SOUTHWEST FLOW WILL KEEP RAIN OVER EASTERN KENTUCKY THROUGH MONDAY MORNING BEFORE ENDING FROM NORTHWEST TO SOUTHEAST ON MONDAY NIGHT. LOW LEVEL MOISTURE MAY BE SLOW ENOUGH TO EXIT BEHIND THE FRONT THAT COLDER AIR MOVING IN MAY ALLOW FOR SOME BRIEF INSTANCES OF SNOW MIXING WITH THE RAIN OR CHANGING TO ALL SNOW IN THE NORTHWEST BLUEGRASS COUNTIES AND THE HIGHER TERRAIN IN THE COUNTIES BORDERING VIRGINIA. ANY INSTANCES THAT DO OCCUR ARE EXPECTED TO BE BRIEF AND NO ACCUMULATION IS EXPECTED. OVERALL...A WET AND RAINY END TO THE WEEKEND AND BEGINNING TO THE NEW WEEK IS ON TAP. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 358 PM EST SAT DEC 27 2014 A COLD FRONT...AND WEAK WAVES OF LOW PRESSURE MOVING ALONG IT...WILL BE EXITING THE AREA TO BEGIN THE EXTENDED PERIOD ON MONDAY. BASED ON THE LATEST MODEL TIME HEIGHTS AND SOUNDINGS...WEAK UPSLOPE FLOW AND RESIDUAL MOISTURE BEHIND THE DEPARTING BOUNDARY MAY ALLOW ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS TO LINGER BEHIND THE FRONT. BASED ON MOISTURE AVAILABILITY AND THE LACK OF ICE CRYSTAL GROWTH ALOFT...PRECIPITATION SHOULD INITIALLY BE IN THE FORM OF RAIN SHOWERS THROUGH AROUND 12Z ON MONDAY. AFTER THAT...ENOUGH COLD AIR SHOULD SPILL INTO THE REGION TO ALLOW SOME SNOW FLURRIES TO MIX WITH SPRINKLES OR LIGHT RAIN SHOWERS MONDAY NIGHT THROUGH EARLY TUESDAY MORNING. THE NAM12 SOUNDINGS SEEMED TO HAVE THE BEST HANDLE ON THE TRANSITION BETWEEN PRECIP TYPES...SO THAT MODEL WAS USED TO CREATE THE POPS AND PRECIP TYPES THROUGH EARLY TUESDAY MORNING. ONCE THE PRECIP EXITS THE AREA TUESDAY MORNING...A RIDGE OF HIGH PRESSURE WILL INFLUENCE THE REGIONS WEATHER THROUGH LATE THURSDAY MORNING. A FAIRLY POTENT AREA OF LOW PRESSURE IS THEN FORECAST TO FORM IN THE SOUTHERN JET STREAM OVER THE SOUTHERN ROCKY MOUNTAINS. AS THIS SYSTEM ADVANCES EASTWARD...THE MODELS HAVE IT TAPPING INTO AMPLE GULF OF MEXICO MOISTURE WEDNESDAY NIGHT AND THURSDAY. SHOULD THE MODELS PAN OUT...THE FIRST PRECIP WOULD ENTER EASTERN KENTUCKY AROUND NOON ON THURSDAY AND GRADUALLY OVERSPREAD THE AREA FROM THERE. BY 2 OR 3Z FRIDAY...THE SYSTEM WILL TAP INTO SOME COLDER AIR...ALLOWING FOR PRECIP ALONG THE NORTHERN FRINGE OF THE PRECIPITATION SHIELD TO MIX WITH SNOW. THE PRECIP SHOULD TRANSITION TO ALL SNOW BY AROUND 6Z FRIDAY AS MORE COLD AIR SPILLS IN FROM THE NORTH. WARMER AIR IS THEN FORECAST TO PROGRESS NORTHWARD INTO THE AREA FRIDAY MORNING...ALLOWING PRECIP TO TRANSITION BACK TO A RAIN SNOW MIX AND THEN RAIN BY EARLY FRIDAY AFTERNOON. AT THIS TIME THERE IS TOO MUCH UNCERTAINTY AS TO THE EXACT TRACK OF THE SOUTHERN STREAM LOW AND THE AMOUNT OF COLD AIR THAT WILL BE AVAILABLE FOR THE TRANSITION TO SNOW. THEREFORE...HAVE ELECTED TO GO WITH ONLY MINIMAL SNOW ACCUMULATIONS THURSDAY NIGHT INTO FRIDAY MORNING. TEMPERATURES THROUGHOUT THE EXTENDED PERIOD LOOK TO BE WELL BELOW NORMAL BASED ON THE CURRENT MOS GUIDANCE. BASED ON THE LATEST MODEL SOUNDINGS...DECIDED TO CONTINUE WITH THIS OVERALL TREND UNTIL THE DATA SETTLES ON A SOLUTION. THE COLDEST DAYS UPCOMING LOOK TO BE TUESDAY THROUGH THURSDAY...AS COLD AIR INVADES BEHIND THE INITIAL FRONTAL BOUNDARY. DAYTIME HIGHS ON THOSE THREE DAYS MAY NOT RISE OUT OF THE 30S ACROSS THE AREA. FRIDAY SHOULD BE SLIGHTLY WARMER AS WINDS SHIFT TO THE SOUTH...WITH HIGH IN THE LOWER 40S ON TAP. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 150 AM EST SUN DEC 28 2014 FLIGHT CONDITIONS WILL DETERIORATE THROUGH THE FIRST FEW HOURS OF THE FORECAST AS DRIZZLE AND LIGHT RAIN OVERSPREAD THE AREA FROM THE WEST. FOLLOWED MODEL GUIDANCE...BRINGING CONDITIONS DOWN GRADUALLY. BUT OBSERVATIONS AT LEAST INITIALLY SUGGEST A QUICKER TRANSITION. LIGHT RAIN AND DRIZZLE WILL LINGER THROUGH THE DAY TODAY WITH SOME IMPROVEMENT POSSIBLE AT THE END OF THE FORECAST WINDOW. WINDS WILL GRADUALLY VEER OUT OF THE NORTHWEST AT AROUND 5 KTS. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...SHALLENBERGER LONG TERM...AR AVIATION...RAY
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
406 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT OVER OHIO WILL MOVE INTO THE AREA TODAY. LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT THIS AFTERNOON AND EVENING... PUSHING THE FRONT SOUTH OF THE AREA. ANOTHER LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CAROLINAS MONDAY AND MONDAY NIGHT. STRONG HIGH PRESSURE WILL BUILD OVER MUCH OF THE COUNTRY BY TUESDAY...AND GRADUALLY PUSH EASTWARD DURING THE REST OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 08Z...1025MB SFC HIGH IS APPROACHING BERMUDA WHILE 999MB SFC LOW IN QUEBEC. THE ASSOCIATED COLD FRONT IS HALFWAY ACROSS OHIO WITH SUBTROPICAL AIR OVER THE MID-ATLANTIC. AN UPR TROUGH AXIS IS OVER THE SRN GREAT PLAINS. TEMPERATURES HAVE RISEN OVER THE CWA WITH AN INCREASE IN CLOUD COVER WITH TEMPERATURES IN MIXED AREAS IN THE UPR 40S TO AROUND 50F. SOME POCKETS OF UPR 30S PERSIST IN DECOUPLED AREAS. RAPID INCREASES INTO THE MID OR POSSIBLY UPR 50S ARE POSSIBLE THIS MORNING WITH 14C AIR AT 925MB OVER THE AREA. HOWEVER... THICKENING CLOUDS SHOULD GENERALLY KEEP MAX TEMPS IN THE LOW TO MID 50S OVER THE AREA. THE LAST LEADING SHOWERS (FOR NOW) ARE MOVING EAST ACROSS THE NRN BALTIMORE METRO. ONLY ISOLATED SHOWERS ARE EXPECTED AHEAD OF THE COLD FRONT THROUGH THE MID-MORNING HOURS. THE COLD FRONT IS PROGGED BY THE 06Z HRRR TO REACH THE POTOMAC HIGHLANDS IN THE MID-MORNING HOURS. FORWARD PROGRESS WILL SLOW FROM THERE AS SHORTWAVE TROUGHS SPREAD NORTHEAST UP THE PARENT UPR TROUGH. WIDESPREAD LIGHT RAIN IS EXPECTED ACROSS THE AREA THIS AFTERNOON WITH QPF GENERALLY LESS THAN TWO TENTHS INCH. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... PERIODIC LIGHT RAIN WILL DRIFT SOUTH WITH THE FRONTAL BOUNDARY INTO MONDAY. PERHAPS AN ADDITIONAL TENTH INCH RAIN...PARTICULARLY SOUTH OF DC. NORTHWEST WINDS INCREASE TO AROUND 10 MPH TONIGHT WITH COLD AIR ADVECTION RESULTING IN MIN TEMPS OF LOW 30S FOR NRN AND WESTERN FRINGES...MID TO UPR 30S ELSEWHERE. RAIN ENDS AS SNOW FOR THESE FRINGE AREAS NEAR THE MASON-DIXON LINE AND FOR RIDGES. NO SNOW AMOUNTS WERE ADDED AS OF YET WITH LOW POPS...BUT THERE IS THE POSSIBILITY OF A DUSTING...PARTICULARLY AT HIGH ELEVATIONS. 21Z SREF WAS EAGER TO HAVE HIGH POPS IN FOR MOST OF THE CWA THROUGH MONDAY. HOWEVER...WENT WITH CONSENSUS OF NAM/GFS/ECMWF WITH HAVING LIKELY POPS FOR RAIN LIMITED TO SRN MD MONDAY MORNING. LOW LEVEL FLOW IS MORE NELY MONDAY AFTERNOON...WHICH WOULD PROMOTE CHANCE POPS FOR RAIN/SNOW MIX OVER TERRAIN THE SWRN PART OF THE CWA. NO WINTRY ACCUMULATION THERE EITHER WITH JUST CHANCE POPS. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... BASICALLY THE EXTENDED BOILS DOWN TO TWO PRECIP SYSTEMS AT THE START AND END OF THE LONG TERM WITH COLD HIGH PRESSURE SANDWICHED IN BETWEEN. MON AND MON NIGHT...STILL SOME UNCERTAINTY BASED ON MODEL SPREAD OF PRECIPITATION FOR MON. 00Z/NAM AND GFS SOLNS SHOW MOST OF THE PRECIP SLIPPING SOUTH AND EAST OF THE CWA EARLY MONDAY AM. BUT 00Z/ECMWF LINGERS SOME MOISTURE ACROSS SRN TIER OF ZNS. KEPT SLIGHT TO CHANCE POPS IN FOR MON OVER THE CWA...AND WITH TEMPS COLD ALOFT BUT BOUNDARY TEMPS ABOVE FREEZING...MENTIONED RAIN/SNOW MIX POSSIBLE. BY MON NIGHT...LINGERING MOISTURE ACROSS SOUTHERN TIER OF ZONES WARRANT CHANCE POPS...WITH LIKELY POPS IN FAR SW PORTION OF CWA ACROSS HIGHLAND COUNTY AND SRN PENDLETON COUNTIES...AND COLD ENOUGH THERE FOR ACCUMULATING SNOW AROUND AN INCH IN UPSLOPE AREAS. TUE...COLD AIR LOFT IS A CERTAINTY AS THE LARGE POLAR AIR MASS SETTLES OVER MUCH OF THE CONUS EAST OF THE ROCKIES. THE 00Z/NAM AND 03Z/SREF ARE AGAIN SHOW BEING AGGRESSIVE WITH A WEAK DISTURBANCE THAT THE 00Z/GFS/ECMWF/UKMO SOLNS SHOW A MUCH WEAKER AND FLATTER SYSTEM THAT STAYS SOUTH. AT THIS POINT ANY PRECIP AMOUNTS TUE WILL BE LIGHT BUT COULD BE IN FORM OF SNOW. WED-FRI...HIGH PRESSURE DOMINATES WITH SEASONABLY COLD WEATHER AND DRY CONDITIONS. LATE FRI-SAT...NEXT SYSTEM WILL APPROACH FROM THE SOUTHWEST AS MODELS SHOW A LARGE LOW PRESSURE SYSTEM MOVING FROM THE CENTRAL PLAINS LATE FRI MOVING INTO THE UPPER GREAT LAKES ON SAT. THIS SYSTEM LOOKS LIKE IT COULD BRING A WINTRY MIX INITIALLY FRIDAY NIGHT WITH THE EXPECTED TRACK OF THE LOW NORTHWEST OF THE CWA... LOTS OF WARM AIR WILL BE ADVECTED INTO THE AREA...CHANGING PRECIP TO LIQUID BY SAT MORNING. OF COURSE...TIMING AND POSITION AND TRACK OF THE LOW IS LOW CONFIDENCE AT THIS POINT. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... VFR CONDS THROUGH THE MORNING AS RAIN ASSOCIATED WITH A COLD FRONT APPROACHES FROM THE OHIO VALLEY TODAY. MVFR CONDS THIS AFTERNOON IN MAINLY LIGHT RAIN. FRONT STALLS/DRIFTS SOUTH TONIGHT...SO CONDS CONTINUE TO LOWER WITH IFR POSSIBLE...BUT KEPT 06Z TAFS WITH MVFR CIGS. LIGHT WLY FLOW TODAY...NWLY FLOW UP TO 10 KT TONIGHT...NLY FLOW 10 KT MONDAY. MVFR TO IFR CIGS/VSBYS MON AND MON EVENING. VFR CONDITIONS TUE THROUGH THU...WITH POSSIBLE MVFR CIGS IN SNSH- ACTIVITY TUE. && .MARINE... LIGHT SWLY FLOW VEERS NWLY TODAY AS A COLD FRONT CROSSES THE WATERS THIS AFTERNOON AND EVENING. COULD BE A NLY SURGE WITH GUSTS AROUND 18 KT LATE TONIGHT. DID NOT RAISE AN SCA DUE TO UNCERTAINTY...BUT ONE OUT OF SANDY POINT IS POSSIBLE INTO MONDAY. MON-WED...EXPECT WINDS TO REMAIN BELOW SCA LEVELS. PRECIP ON MON PUSHES SOUTH AND EAST LATE MON. HIGH PRESSURE BUILDS IN TUE AND CONTINUES THROUGH END OF THE WEEK. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BAJ NEAR TERM...BAJ SHORT TERM...BAJ LONG TERM...SMZ AVIATION...BAJ MARINE...BAJ/SMZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
610 PM EST MON DEC 29 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 403 PM EST MON DEC 29 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH EXTENDING FROM NRN QUEBEC THROUGH THE NRN PLAINS INTO THE ROCKIES. THE NEXT SIGNIFICANT UPSTREAM SHORTWAVE TROUGH WAS DROPPING SOUTH THROUGH NRN SASK/MANITOBA. AT THE SFC...1054 MB ARCTIC HIGH PRES OVER ALBERTA EXTENDED INTO THE NRN PLAINS AND UPPER MS VALLEY AND NRN LAKES RESULTING IN A FLOW OF VERY COLD AIR ACROSS LAKE SUPERIOR ON NW WINDS. DESPITE 850 MB TEMPS NEAR -21C...LES HAS BEEN LIMITED BY THE VERY DRY UPSTREAM CONDITIONS AS THE BACK EDGE OF THE CLOUDS WAS CLOSER TO THE MI SHORE IN THE WEST AND NEAR THE CENTER OF THE NRN LAKE. RADAR SHOWED MAINLY WEAK WIND PARALLEL BANDS INTO THE ERN CWA. TONIGHT...WITH THE LOSS OF DAYTIME MIXING AND ONSET OF LAND BREEZES THE LES MAY BECOME BETTER ORGANIZED. THE PERSISTENT 290-300 FLOW LES IS EXPECTED TO CONTINUE BUT WILL BE LIMITED BY 4K FT INVERSION HEIGHTS AND A LACK OF ANY SUSTAINED AREAS OF LOW LEVEL CONV. THE LONGER FETCH INTO THE EAST WILL SUPPORT SNOWFALL AMOUNTS IN THE 2 TO 4 INCH RANGE WITH SLR VALUES NEAR 25/1...E OF MUNISING WHILE OVER THE WEST ONLY 1 TO 3 INCH AMOUNTS ARE EXPECTED. WIND CHILL VALUES OVER THE INTERIOR WEST COULD FALL INTO THE -20 TO -25 RANGE AS SFC TEMPS DROP TO AROUND -8F. HOWEVER...WINDS SHOULD REMAIN LESS THAN 10 MPH. TUESDAY...EXPECT THE WINDS TO BACK MORE WRLY AHEAD OF THE SASK/MANITOBA SHORTWAVE TROUGH...ESPECIALLY IN THE AFTERNOON. OTHERWISE...LIGHT TO MODERATE WNW FLOW LES WILL CONTINUE WITH 850 MB TEMPS REMAINING NEAR -22C AND INVERSION HEIGHTS AROUND 4K FT. THE STRONGEST LOW LEVEL CONV...INFLUENCED BY LAKE-INDUCED TROUGHING IS EXPECTED OVER THE ERN LAKE WITH SOME STRONGER BANDS POSSIBLE CLIPPING THE NE PORTION OF LUCE COUNTY. FOR NOW...EXPECT ADDITIONAL ACCUMULATIONS IN THE 2 TO 4 INCH RANGE E OF P53 AND 1 TO 3 INCHES INTO THE WEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 426 PM EST MON DEC 29 2014 A BROAD UPPER TROUGH OVER CANADA AND THE GREAT LAKES REGION WILL LEAD TO BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW THROUGH THE FIRST WEEK OF 2015. AT THE START OF THE PERIOD...THE AREA WILL STILL BE BETWEEN A STRONG HIGH OVER WESTERN NEBRASKA AND A LOW JUST TO THE NORTH OF HUDSON BAY. ALOFT...A SHORTWAVE WILL JUST BE DEPARTING THE AREA AND BRINGING ONE LAST SURGE OF -21C 850MB TEMPS TO THE AREA. THUS...EXPECT NORTHWEST FLOW LAKE EFFECT TO STILL BE ONGOING TUESDAY EVENING. A SURFACE TROUGH DIVING SOUTHEAST FROM THE HUDSON BAY LOW WILL LEAD TO BACKING FLOW ON TUESDAY NIGHT INTO WEDNESDAY MORNING...SHIFTING THE LAKE EFFECT TO THE WESTERLY FLOW AREAS (THE KEWEEANW AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE EAST OF MUNISING). SNOWFALL AMOUNTS TUESDAY NIGHT CONTINUE TO LOOK LIGHT AND FLUFFY AS INVERSION HEIGHTS ARE STILL IN THE 4-5KFT RANGE WITH MUCH OF THE CLOUD LAYER IN THE DGZ. WILL FOLLOW THE SNOWFALL AMOUNTS SEEN OVER THE LAST 12/24HRS AND HAVE THEM BE IN THE 1-4IN/12HRS RANGE. TUESDAY NIGHT WILL BE ANOTHER COLD NIGHT AWAY FROM THE LAKE EFFECT CLOUDS...WITH LOWS FALLING INTO THE SINGLE DIGITS AND LOWER TEENS BELOW ZERO. WIND CHILLS WILL BECOME A CONCERN LATE IN THE NIGHT INTO WEDNESDAY MORNING...AS THE WEST TO SOUTHWEST WINDS BEGIN TO INCREASE WITH THE TIGHTENING PRESSURE GRADIENT. WHILE THIS WILL LIKELY INCREASE MIXING AND IN TURN WARM TEMPS SLIGHTLY (HELPED BY SOME MID CLOUDS MOVING IN)...THERE WILL STILL BE A PERIOD LATE TUESDAY NIGHT INTO WEDNESDAY MORNING WHERE WIND CHILL VALUES WILL BE IN THE -20 TO -30 DEGREE RANGE OVER THE INTERIOR LOCATIONS. WILL CONTINUE TO MENTION THIS IN THE HWO AND AN ADVISORY MAY BEEN NEEDED TOMORROW. WITH THE LOW LEVEL WINDS TRYING TO BACK TOWARDS THE SOUTHWEST DURING THE DAY WEDNESDAY...DID TRY TO SHOW BETTER TIMING ON THE LAKE EFFECT SNOW. EXPECT IT TO TRY TO SHIFT OVER THE FAR NORTHERN PART OF THE KEWEENAW BY MID DAY AND WELL OFFSHORE OVER THE EAST. WINDS WILL BECOME QUITE GUSTY DURING THIS PERIOD...WITH MUCH OF UPPER MICHIGAN EXPERIENCING GUSTS IN THE 25 TO 35MPH RANGE. BUT OVER THE KEWEENAW PENINSULA AND CLOSER TO THE TIGHTER PRESSURE GRADIENT...WOULD EXPECT GUSTS TO AT LEAST 40 MPH AND AT TIMES 45-50MPH. THESE WINDS COMBINED WITH THE FLUFFY LAKE EFFECT SEEN OVER THE LAST COUPLE OF DAYS WILL LIKELY LEAD TO SIGNIFICANT BLOWING SNOW DEVELOPING THROUGH THE DAY WEDNESDAY. THEN...AS STRONG SHORTWAVE DIVES SOUTHEAST ACROSS THE UPPER GREAT LAKES REGION DURING THE AFTERNOON AND THE SURFACE TROUGH DURING THE EARLY EVENING...EXPECT WINDS TO SHIFT BACK TO THE WEST AND REFOCUS THE LAKE EFFECT IN THE WESTERLY WIND AREAS. THINK THERE COULD BE A PERIOD OF MODERATE SNOW AS THE WINDS TURN TO THE WEST...DUE TO INVERSION HEIGHTS RISING TO 7KFT AND MUCH OF THE CLOUD STILL IN THE DGZ. THERE ARE A COUPLE DOWNSIDES TO HIGHER SNOWFALL AMOUNTS (TIED TO THE STRONG WINDS)...BUT THERE WILL STILL BE VERY POOR CONDITIONS OVER THE KEWEENAW. FIRST...THE HIGH WINDS WILL LIMIT THE RESIDENCE TIME OVER THE WESTERN LAKE AS THEY SHIFT TO THE WEST. SECOND...THE STRONG WINDS WILL BREAK UP THE DENDRITES FROM THE FAVORABLE CLOUD LAYER AND LEAD TO SMALLER/FRACTURED FLAKES. WHILE THIS WILL LIMIT SNOWFALL AMOUNTS...IT WILL BE MORE EFFECTIVE AT REDUCING VISIBILITIES AND WHEN COMBINED WITH THE BLOWING SNOW...WOULD EXPECT VISIBILITIES BELOW 1/4 MILE AT TIMES LATE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. WILL CONTINUE TO MENTION THESE POOR CONDITIONS FOR THE KEWEENAW IN THE HWO. EXPECT NORTHWEST FLOW LAKE EFFECT TO REESTABLISH ON THURSDAY FOR AREAS DOWNSTREAM FROM LAKE SUPERIOR. ELSEWHERE IN THE U.P...MODELS DIFFER IN THEIR SOLUTIONS ON POTENTIAL SHORTWAVES ZIPPING EAST-SOUTHEAST ACROSS THE AREA. AT TIMES...MODELS HAVE SHOWN LIGHT SNOW ASSOCIATED WITH THESE QUICK WAVES THURSDAY AND AGAIN FRIDAY. BOTH STRENGTH AND LOCATIONS HAS NOT BEEN CONSISTENT IN THE MODELS OVER THE LAST 24 HOURS...SO WILL FOCUS LARGELY ON LAKE EFFECT TURNING TO THE WESTERLY WIND LOCATIONS AND SHOW SLIGHT CHANCES ELSEWHERE. THE UNCERTAINTY CONTINUES INTO THE WEEKEND...AS MODELS DIFFER ON HOW THE CLOSED UPPER LOW THAT DEVELOPS OVER THE SOUTHWEST CONUS TUESDAY INTERACTS WITH THE NORTHERN STREAM JET AS IT SHIFTS EAST ACROSS THE SOUTHERN CONUS. THE 12Z GFS/GEM SOLUTIONS MERGE THE UPPER LOW WITH A MORE AMPLIFIED NORTHERN STREAM TROUGH AND THEN LIFT IT AND A DEVELOPING SURFACE LOW NORTHEAST THROUGH THE LOWER GREAT LAKES SATURDAY NIGHT. MEANWHILE...THE 12Z ECMWF AND ITS ENSEMBLE MEMBERS SHOW A MUCH FLATTER NORTHERN STREAM TROUGH AND DON/T MERGE THE WAVES UNTIL THE EAST COAST ON SUNDAY. THAT WOULD LEAD TO MORE OF A NORTHERLY FLOW LAKE EFFECT FOR THE AREA. THIS WILL DEFINITELY BE SOMETHING TO WATCH OVER THE COMING DAYS. EVEN IF THERE ISN/T A LOW MOVING THROUGH THE LOWER GREAT LAKES...TEMPERATURES WILL BE COLD ENOUGH FOR LAKE EFFECT SNOW AND WILL CONTINUE TO SHOW THE POTENTIAL IN THE GRIDS FOR AREAS NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 609 PM EST MON DEC 29 2014 EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH BETTER CONDITIONS AT SAW. COLD AIR ON NORTHWEST WINDS OVER THE RELATIVELY WARM LAKE SUPERIOR WATERS WILL KEEP LES GOING AT IWD AND CMX. ANOTHER UPPER LEVEL DISTURBANCE HELPS BOOST THE POTENTIAL FOR LAKE EFFECT SNOW SHOWERS AT CMX ONCE AGAIN. AT THAT POINT WINDS OVER N WI AND FAR W UPPER MI SHOULD BECOME MORE WRLY...LIMITING POTENTIAL FOR MUCH MORE THAN FLURRIES AT IWD OVERNIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 403 PM EST MON DEC 29 2014 EXPECT HEAVY FREEZING SPRAY BY TUESDAY AFTERNOON AND GALES FROM LATE TUESDAY NIGHT THROUGH THURSDAY MORNING. A RIDGE ACROSS THE UPPER GREAT LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS WILL BE AS A HUDSON BAY LOW DRAGS A TROUGH ACROSS LAKE SUPERIOR. THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-45KTS ARE STILL ANTICIPATED /ALONG WITH HEAVY FREEZING SPRAY TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE TRACKS ACROSS THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO 1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263- 265>267. GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ264>267. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-263. HEAVY FREEZING SPRAY WARNING FROM 1 AM TUESDAY TO 1 PM EST THURSDAY FOR LSZ264. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST /6 PM CST/ WEDNESDAY FOR LSZ241>245. HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246-247. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
435 PM EST SUN DEC 28 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 216 PM EST SUN DEC 28 2014 PERSISTENT LIGHT AND FLUFFY LAKE EFFECT IN THE NORTHWEST WIND SNOW BELTS WILL BE THE NORM FOR THE SHORT TERM FORECAST. A SURFACE TROUGH SWEPT SOUTHEAST ACROSS UPPER MICHIGAN THIS MORNING AND EARLY AFTERNOON AND HAS SWITCHED WINDS TO THE NORTHWEST AND BROUGHT MUCH COLDER AIR INTO THE AREA. 850MB TEMPS AT THIS TIME ON THE RAP ANALYSIS ARE -18C OVER WESTERN LAKE SUPERIOR AND WESTERN UPPER MICHIGAN. THIS COLD AIR...AIDED BY MOISTURE FROM THE SURFACE TROUGH THAT SWEPT THROUGH THE AREA...LED TO SOME LAKE EFFECT SNOW IN THE WEST AND NOW NORTHWEST WIND SNOWBELTS THROUGH THE DAY. WHILE THERE WERE SOME STRONGER SHOWERS THIS MORNING...ASSISTED BY CONVERGENCE ALONG THE FRONT AND FROM THE SOUTHERN EDGE OF THE SHORTWAVE MOVING EAST JUST TO THE NORTH OF LAKE SUPERIOR...THEY HAVE NOW TRANSITIONED TO MORE OF A MULTIBAND LES LOOK ON SATELLITE OVER WESTERN UPPER MICHIGAN. USING THE EXPERIMENTAL SSEC SATELLITE DERIVED SNOWFALL RATES...IT APPEARS THAT SOME AREAS ARE SEEING TRANSIENT BANDS OF 0.5 IN/HR RATES AND THAT SEEMS TO MATCH UP WITH VISIBILITY REPORTS AT KCMX. WITH THE DEEPER MOISTURE STARTING TO PULL OUT OF THAT AREA...HAVE ALREADY SEEN SOME WEAKENING OVER WESTERN LAKE SUPERIOR...HELPED BY INVERSION HEIGHTS FALLING BEHIND THE TROUGH. THE 12Z KINL SOUNDING HAD INVERSION HEIGHTS AROUND 900MB OR 3KFT...BUT WITH SOME LAKE MODIFICATION THEY SHOULD BE IN THE 4-5KFT RANGE. OVER THE EAST...THERE WAS A STRONGER BAND BETWEEN MUNISING AND MINER/S CASTLE THIS MORNING THAT LIKELY PRODUCED A COUPLE-FEW INCHES OF SNOW. THIS BAND WAS AIDED BY THE CONVERGENT FLOW OFF MARQUETTE COUNTY AHEAD OF THE SURFACE TROUGH. BUT NOW THAT THE TROUGH IS MOVING THROUGH NORTH CENTRAL UPPER MICHIGAN...THE BAND HAS BECOME MUDDLED. WITH THE LAKE EFFECT TRANSITIONING TO MULTIBAND OVER THE EASTERN LAKE...ACCUMULATIONS SHOULD BE LIMITED THE REST OF THE AFTERNOON. OVERALL...LITTLE CHANGE IN THE OVERALL CONDITIONS OVER THE CWA DURING THE SHORT TERM PERIOD...AS HIGH PRESSURE RIDGE BUILDS OVER THE AREA FROM A STRONG HIGH IN NORTHWEST CANADA. WITH 875MB TEMPS FALLING TO -21C...EXPECT HIGH POP LOW QPF LAKE EFFECT TO CONTINUE THROUGH THE PERIOD IN THE NORTHWEST WIND SNOWBELTS. THERE DOES APPEAR TO BE A BRIEF PERIOD OF BACKING WINDS OVERNIGHT AS A WEAK TROUGH MOVES THROUGH TONIGHT BEFORE SETTLING BACK TO NORTHWEST WINDS FOR MONDAY. THIS WEAK TROUGH WILL BRING A LITTLE MORE LOW LEVEL MOISTURE TO THE AREA FOR THE LAKE EFFECT TO WORK WITH LATE TONIGHT INTO MONDAY MORNING (SEEN ON THE 12Z CWPL SOUNDING). BUT THE RIDGE MOVING OVER THE AREA WILL KEEP THE LOWER INVERSION HEIGHTS IN PLACE THROUGH THE PERIOD AND KEEP SNOWFALL AMOUNTS IN CHECK. FOR TONIGHT AND AGAIN ON MONDAY...HAVE THE NORTHWEST WIND SNOW BELTS RECEIVING 1-3 INCHES OF FLUFFY SNOW EVERY 12 HOURS...LARGELY HELPED BY THE ENTIRE CLOUD BEING WITHIN THE DGZ. WITH THE LONGER FETCH AND IN TURN LAKE MODIFICATION...HAVE A LITTLE HIGHER AMOUNTS OVER THE EAST BUT STILL ONLY LOCALIZED 4 INCH AMOUNTS. THERE ARE SOME INDICATIONS OF LOW LEVEL DRYING LATE TOMORROW AFTERNOON WHICH COULD WEAKEN THE LAKE EFFECT SOME AND HAVE LOWERED THE POPS A LITTLE TO ACCOUNT FOR THAT. AS IS NORMALLY THE CASE IN THE LAKE EFFECT REGIMES...LOWS TONIGHT WILL DEPEND ON CLOUD COVER. WHERE CLEARING IS EXPECTED TO OCCUR...HAVE LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO. OTHERWISE...UNDER THE CLOUDS WOULD EXPECT TEMPS IN THE UPPER SINGLE DIGITS OR LOWER TEENS. HIGHS TOMORROW WILL BE CLOSE TO 10 DEGREES BELOW NORMAL AND IN THE TEENS ABOVE ZERO. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 434 PM EST SUN DEC 28 2014 TODAYS MEDIUM RANGE MODELS STRONGLY SUPPORT LONG TERM FCST PRODUCED OVER THE LAST 3 DAYS. SO...FCST CHANGES IN THE LONG TERM TODAY WILL BE MINOR. BIGGEST FCST CHALLENGE WILL OCCUR AT THE END OF THE WEEK/WEEKEND. MORE ON THAT LATER. THE LONG ADVERTISED SIGNIFICANT PATTERN CHANGE ACROSS NAMERICA IS NOW WELL UNDERWAY AS A STRONG RIDGE IS BUILDING N THRU ALASKA. 12Z RAOBS SHOW 12HR 500MB HEIGHT RISES OF 130-150M IN NRN ALASKA/ADJACENT FAR NW CANADA...AND HEIGHT ANOMALIES ARE NOW 2 STANDARD DEVIATIONS ABOVE THE LONG TERM LATE DEC AVG. 500MB HEIGHT ANOMALIES ARE STILL FCST TO PEAK AT 2.5 STANDARD DEVIATIONS LATER TODAY THRU EARLY WED. OF COURSE...THE DOWNSTREAM RESPONSE WILL BE A DEVELOPING CNTRL/ERN NAMERICA TROF. THIS AMPLIFIED PATTERN WILL ALLOW THE BUILDUP AND EXPANSION OF ARCTIC AIR ACROSS CANADA THAT WILL SPILL S INTO THE CONUS...SIMILAR TO THE PATTERN OBSERVED MOST OF LAST WINTER AND LAST MONTH. SO...AFTER AN EXTENDED PERIOD OF MOSTLY ABOVE NORMAL TEMPS OVER THE LAST 3 WEEKS...A BLO NORMAL TEMP REGIME WILL TAKE HOLD ON MON AND CONTINUE THRU AT LEAST THE NEXT 10 DAYS...THOUGH A DAY OR TWO MAY SEE TEMPS CLOSE TO NORMAL DURING THAT TIME. THERE ARE INDICATIONS THAT THE MOST SIGNIFICANT CHILL COULD OCCUR IN THE 7-10 DAY TIME FRAME. FARTHER OUT TO DAY 16...MAJORITY OF GEM ENSEMBLES STILL INDICATE DEAMPLIFICATION AND A TREND BACK TOWARD NORMAL TEMPS BY MID JAN. CFSV2 GOES FURTHER TO BRING A RETURN OF A WARM PATTERN/ABOVE NORMAL TEMPS FOR MID/LATE JAN. WE`LL SEE. AS FOR PCPN...PCPN THIS WEEK WILL BE CONFINED ALMOST EXCLUSIVELY TO THE LAKE EFFECT SNOW BELTS NEAR LAKE SUPERIOR AS COLD NW FLOW PREVAILS. AS HAS BEEN THE CASE THE LAST FEW DAYS...THERE CONTINUE TO BE INDICATIONS THAT A LOW PRES SYSTEM COULD TRACK FROM THE SRN PLAINS TO THE GREAT LAKES LATE WEEK/WEEKEND. WHILE THIS STILL SEEMS LIKE A LOW PROBABILITY BASED ON ALL AVBL MEDIUM RANGE GUIDANCE (AT LEAST AS FAR AS BRINGING SIGNIFICANT PCPN INTO UPPER MI)...THERE ARE SUBTLE MULTI-MODEL TRENDS SUPPORTING AN INCREASED LIKELIHOOD OF AT LEAST WIDESPREAD -SN...INCLUDING LAKE ENHANCEMENT NEAR LAKE SUPERIOR. LATE WEEK/WEEKEND WILL CONTINUE TO BE A TIME FRAME TO MONITOR IN THE COMING DAYS. BEGINNING MON NIGHT THRU TUE NIGHT...THE COLDEST AIR OF THIS INITIAL SURGE OF ARCTIC AIR WILL SETTLE OVER THE AREA ON TUE WHEN 850MB TEMPS BOTTOM OUT AROUND -23C. THIS WILL RESULT IN TUE LIKELY BEING THE COLDEST DAY THIS WEEK FOR MOST AREAS. MAX TEMPS IN GENERAL WILL BE IN THE 5 TO 15F RANGE...THOUGH OVER THE FAR W AROUND KIWD...TEMPS MAY ONLY RISE TO JUST ABOVE 0F. MON NIGHT AND TUE NIGHT...SUBZERO MIN TEMPS WILL BE THE RULE IN THE INTERIOR AWAY FROM LAKE EFFECT CLOUDS/SNOW. TUE NIGHT WILL LIKELY BE COLDEST WITH TEMPS IN THE INTERIOR W HALF SLIPPING TO -10F OR LWR. SUBZERO TEMPS SHOULD COVER A WIDER AREA ON TUE NIGHT AS WELL SINCE WINDS BACKING MORE WESTERLY WILL RESULT IN LESS LAKE EFFECT CLOUDS/SHSN COVERAGE OVER UPPER MI. COMBINED WITH SOME INCREASE IN WINDS...WIND CHILLS WILL DROP INTO THE -15 TO -25F RANGE TUE NIGHT INTO WED MORNING. WITH SUCH COLD AIR...NMRS SNOW SHOWERS WILL CONTINUE IN THE SNOW BELTS FAVORED BY NW TO W WINDS. NAM/GFS FCST SOUNDINGS SHOW INVERSIONS AT 4-5KFT...SO LES WILL OVERALL BE ON THE LIGHT SIDE (1-4IN/12HRS). HOWEVER...WHERE FETCH ACROSS THE LAKE IS LONGEST...ALLOWING MOST LAKE MODERATION... DGZ WILL DOMINATE THE CONVECTIVE LAYER...AND THIS MAY ALLOW FOR SOME ADVY LEVEL SNOW ACCUMULATIONS...IN PARTICULAR WHERE LONGER FETCH AND LOCALIZED ENHANCED CONVERGENCE WORK TOGETHER. SIMILAR TO THE LAST FEW DAYS OF MODEL RUNS...SHORTWAVE TROF SWINGING ACROSS THE AREA ON TUE WILL HAVE SOME IMPACT ON INCREASING MOISTURE DEPTH/RAISING INVERSION HEIGHTS (FOR ROUGHLY 6HRS)...RESULTING IN AN INCREASE IN LES COVERAGE/INTENSITY FOR A TIME. SO...DAYLIGHT HRS ON TUE PROBABLY OFFER THE BEST POTENTIAL FOR LES TO PRODUCE ADVY LEVEL ACCUMULATIONS IN THE SNOW BELTS FAVORED BY NW WINDS. ON NEW YEARS EVE DAY...LOW-LEVEL WINDS WILL BACK TO THE WSW OR EVEN SW IN RESPONSE TO THE NEXT SHORTWAVE TROF SWINGING SE THRU MANITOBA INTO NRN ONTARIO. THIS WILL CAUSE LES TO SHIFT OFFSHORE OF UPPER MI. HOWEVER...UP AT 850MB...WINDS REMAIN OUT OF THE W. SO...LES WILL LIKELY CONTINUE TO AFFECT THE KEWEENAW PENINSULA. TIGHTENING PRES GRADIENT BTWN HIGH PRES OVER THE CNTRL/SRN PLAINS AND LOW PRES OVER HUDSON BAY WILL RESULT IN INCREASING SFC WINDS...ESPECIALLY OVER THE EXPOSED KEWEENAW WHERE 950MB WINDS ARE FCST AT 35-40KT. BLSN MAY BECOME AN ISSUE THERE ON NEW YEARS EVE...ESPECIALLY IF SHSN COVERAGE REMAINS NMRS OR GREATER. NEXT ARCTIC COLD FRONT ASSOCIATED WITH AFORMENTIONED SHORTWAVE TROF SWINGING ACROSS NRN ONTARIO WILL THEN SWEEP ACROSS THE AREA EARLY ON NEW YEARS DAY...ENHANCING LES FOR A TIME AND PROBABLY BRINGING AT ISOLD/SCT -SHSN TO THE REMAINDER OF THE AREA. LES WILL CONTINUE ON INTO FRI UNDER COLD AIR MASS...BUT THERE IS INCREASING MODEL AGREEMENT THAT WINDS WILL BACK FRI AS HIGH PRES RIDGE SLIPS E OF THE AREA AND PRES FALLS SPREAD OUT OVER THE PLAINS. THE BACKING WINDS AND RESULTING DEVELOPING WAA/ISENTROPIC ASCENT REGIME WILL ALLOW FOR A BAND OF -SN TO DEVELOP OVER THE NRN PLAINS AND THEN STREAK E INTO THE UPPER LAKES...BUT PROBABLY NOT UNTIL FRI NIGHT. ON INTO SAT...MUCH WILL DEPEND ON EVOLUTION OF THE CLOSED LOW THAT WILL BE OVER THE SW STATES MIDWEEK. THE GFS HAS BEEN VERY CONSISTENT ON THE NW SIDE OF GUIDANCE IN TAKING THAT ENERGY INTO THE GREAT LAKES REGION. FOR A NUMBER OF RUNS...IT HAS TRACKED A SFC LOW NE... ROUGHLY ACROSS THE SE HALF OF LWR MI. THE 00Z ECMWF STARTED TO TREND SLIGHTLY N AND W WITH TRACK...BUT THE 12Z RUN IS MUCH MORE SUPPRESSED WITH THE LOW...A RESULT OF THE NE PACIFIC RIDGE BEING LESS PRONOUNCED WHICH LEADS TO FLATTER DOWNSTREAM FLOW. THERE A FEW MORE GEM ENSEMBLES SIMILAR TO THE GFS TODAY...BUT THEY ARE STILL A DEFINITE MINORITY. MUCH WILL DEPEND ON THE STRUCTURE/AMPLITUDE OF THE NE PACIFIC RIDGE...BUT AT THIS POINT...GIVEN TODAYS AND RECENT DAYS MEDIUM RANGE GUIDANCE...THE PROBABILITY IS STILL VERY LOW FOR THE SFC LOW TO TRACK FAR ENOUGH N AND W TO BRING SIGNIFICANT PCPN TO THE FCST AREA. HOWEVER...AIDED BY NRN STREAM ENERGY...THERE SHOULD BE SOME -SN ACROSS THE FCST AREA ON SAT ALONG WITH THE POTENTIAL FOR LAKE ENHANCEMENT NEAR LAKE SUPERIOR. ARCTIC AIR WILL FLOW BACK INTO THE UPPER LAKES ON SUN...RENEWING LES IN AREAS FAVORED BY NW WINDS. COLDEST AIR OF THE SEASON COULD FOLLOW FOR MON/TUE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1250 PM EST SUN DEC 28 2014 A SURFACE TROUGH MOVING ACORSS CENTRAL UPPER MICHIGAN IS LEADING TO A BRIEF BAND OF LIGHT TO ALMOST MODERATE SNOW NEARING KSAW AT THE START OF THE TAF PERIOD. THIS WILL AFFECT THE SITE FOR THE FIRST 30-45 MINUTES AND THEN MOVE OFF TO THE EAST. BEHIND THE TROUGH...NORTHWEST FLOW LAKE EFFECT IS TAKING SHAPE OVER WESTERN LAKE SUPERIOR AND WILL BE THE MAIN ITEM OF CONCERN OVER THE NEXT 24 HOURS. OVERALL...WITH A STRONG INVERSION AROUND 4KFT ABOVE THE SURFACE...DON/T EXPECT THE SNOW SHOWERS TO BECOME TOO STRONG AND HAVE KEPT VISIBILITIES IN THE MVFR TO VFR RANGE AT KCMX/KIWD. LOW LEVEL WINDS DO LOOK TO BACK SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE TROUGH THAT WILL THEN SHIFT WINDS BACK TO THE NORTHWEST AROUND DAYBREAK. THUS...HAVE KEPT VSBYS A LITTLE HIGHER AT KIWD WITH THOSE BACKING WINDS. ONCE THAT WEAK TROUGH MOVES THROUGH...WOULD THINK THAT LIGHT LAKE EFFECT WOULD MOVE BACK INTO THE SITE. OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION FOR KSAW...EXPECT THEM TO TRANSITION TO VFR THIS AFTERNOON AND REMAIN THROUGH MUCH OF THE PERIOD (COULD SEE CEILINGS NEAR MVFR TOMORROW MORNING BEHIND THE TROUGH). && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 216 PM EST SUN DEC 28 2014 AS THE SURFACE TROUGH THAT SLID SOUTHEAST ACROSS LAKE SUPERIOR THIS MORNING CONTINUES SOUTHEAST THROUGH THE LOWER GREAT LAKES...PERSISTENT NORTHWEST WINDS OF 15-25KTS ARE EXPECTED OVER THE LAKE THROUGH TUESDAY. THIS IS DUE TO THE AREA BEING BETWEEN A STRONG HIGH MOVING INTO THE NORTHERN/CENTRAL PLAINS AND A LOW NEAR HUDSON BAY. A SURFACE TROUGH WILL SWEEP ACROSS LAKE SUPERIOR ON WEDNESDAY NIGHT AND TIGHTEN THE PRESSURE GRADIENT ACROSS THE LAKE. THIS IS EXPECTED TO PRODUCE WESTERLY GALES OF 35-40KTS WEDNESDAY INTO THURSDAY MORNING. WITH MUCH COLDER TEMPERATURES MOVING OVER LAKE SUPERIOR OVER THE NEXT SEVERAL DAYS...FREEZING SPRAY IS POSSIBLE FOR MUCH OF THE PERIOD. WITH THE STRONGER WINDS TUESDAY NIGHT INTO THURSDAY...HEAVY FREEZING SPRAY IS EXPECTED OVER MUCH OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...ROLFSON AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
216 PM EST SUN DEC 28 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 216 PM EST SUN DEC 28 2014 PERSISTENT LIGHT AND FLUFFY LAKE EFFECT IN THE NORTHWEST WIND SNOW BELTS WILL BE THE NORM FOR THE SHORT TERM FORECAST. A SURFACE TROUGH SWEPT SOUTHEAST ACROSS UPPER MICHIGAN THIS MORNING AND EARLY AFTERNOON AND HAS SWITCHED WINDS TO THE NORTHWEST AND BROUGHT MUCH COLDER AIR INTO THE AREA. 850MB TEMPS AT THIS TIME ON THE RAP ANALYSIS ARE -18C OVER WESTERN LAKE SUPERIOR AND WESTERN UPPER MICHIGAN. THIS COLD AIR...AIDED BY MOISTURE FROM THE SURFACE TROUGH THAT SWEPT THROUGH THE AREA...LED TO SOME LAKE EFFECT SNOW IN THE WEST AND NOW NORTHWEST WIND SNOWBELTS THROUGH THE DAY. WHILE THERE WERE SOME STRONGER SHOWERS THIS MORNING...ASSISTED BY CONVERGENCE ALONG THE FRONT AND FROM THE SOUTHERN EDGE OF THE SHORTWAVE MOVING EAST JUST TO THE NORTH OF LAKE SUPERIOR...THEY HAVE NOW TRANSITIONED TO MORE OF A MULTIBAND LES LOOK ON SATELLITE OVER WESTERN UPPER MICHIGAN. USING THE EXPERIMENTAL SSEC SATELLITE DERIVED SNOWFALL RATES...IT APPEARS THAT SOME AREAS ARE SEEING TRANSIENT BANDS OF 0.5 IN/HR RATES AND THAT SEEMS TO MATCH UP WITH VISIBILITY REPORTS AT KCMX. WITH THE DEEPER MOISTURE STARTING TO PULL OUT OF THAT AREA...HAVE ALREADY SEEN SOME WEAKENING OVER WESTERN LAKE SUPERIOR...HELPED BY INVERSION HEIGHTS FALLING BEHIND THE TROUGH. THE 12Z KINL SOUNDING HAD INVERSION HEIGHTS AROUND 900MB OR 3KFT...BUT WITH SOME LAKE MODIFICATION THEY SHOULD BE IN THE 4-5KFT RANGE. OVER THE EAST...THERE WAS A STRONGER BAND BETWEEN MUNISING AND MINER/S CASTLE THIS MORNING THAT LIKELY PRODUCED A COUPLE-FEW INCHES OF SNOW. THIS BAND WAS AIDED BY THE CONVERGENT FLOW OFF MARQUETTE COUNTY AHEAD OF THE SURFACE TROUGH. BUT NOW THAT THE TROUGH IS MOVING THROUGH NORTH CENTRAL UPPER MICHIGAN...THE BAND HAS BECOME MUDDLED. WITH THE LAKE EFFECT TRANSITIONING TO MULTIBAND OVER THE EASTERN LAKE...ACCUMULATIONS SHOULD BE LIMITED THE REST OF THE AFTERNOON. OVERALL...LITTLE CHANGE IN THE OVERALL CONDITIONS OVER THE CWA DURING THE SHORT TERM PERIOD...AS HIGH PRESSURE RIDGE BUILDS OVER THE AREA FROM A STRONG HIGH IN NORTHWEST CANADA. WITH 875MB TEMPS FALLING TO -21C...EXPECT HIGH POP LOW QPF LAKE EFFECT TO CONTINUE THROUGH THE PERIOD IN THE NORTHWEST WIND SNOWBELTS. THERE DOES APPEAR TO BE A BRIEF PERIOD OF BACKING WINDS OVERNIGHT AS A WEAK TROUGH MOVES THROUGH TONIGHT BEFORE SETTLING BACK TO NORTHWEST WINDS FOR MONDAY. THIS WEAK TROUGH WILL BRING A LITTLE MORE LOW LEVEL MOISTURE TO THE AREA FOR THE LAKE EFFECT TO WORK WITH LATE TONIGHT INTO MONDAY MORNING (SEEN ON THE 12Z CWPL SOUNDING). BUT THE RIDGE MOVING OVER THE AREA WILL KEEP THE LOWER INVERSION HEIGHTS IN PLACE THROUGH THE PERIOD AND KEEP SNOWFALL AMOUNTS IN CHECK. FOR TONIGHT AND AGAIN ON MONDAY...HAVE THE NORTHWEST WIND SNOW BELTS RECEIVING 1-3 INCHES OF FLUFFY SNOW EVERY 12 HOURS...LARGELY HELPED BY THE ENTIRE CLOUD BEING WITHIN THE DGZ. WITH THE LONGER FETCH AND IN TURN LAKE MODIFICATION...HAVE A LITTLE HIGHER AMOUNTS OVER THE EAST BUT STILL ONLY LOCALIZED 4 INCH AMOUNTS. THERE ARE SOME INDICATIONS OF LOW LEVEL DRYING LATE TOMORROW AFTERNOON WHICH COULD WEAKEN THE LAKE EFFECT SOME AND HAVE LOWERED THE POPS A LITTLE TO ACCOUNT FOR THAT. AS IS NORMALLY THE CASE IN THE LAKE EFFECT REGIMES...LOWS TONIGHT WILL DEPEND ON CLOUD COVER. WHERE CLEARING IS EXPECTED TO OCCUR...HAVE LOWS IN THE SINGLE DIGITS ABOVE/BELOW ZERO. OTHERWISE...UNDER THE CLOUDS WOULD EXPECT TEMPS IN THE UPPER SINGLE DIGITS OR LOWER TEENS. HIGHS TOMORROW WILL BE CLOSE TO 10 DEGREES BELOW NORMAL AND IN THE TEENS ABOVE ZERO. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 431 AM EST SUN DEC 28 2014 THIS PERIOD WILL BE MARKED BY COLD CONDITIONS WITH PERSISTENT LES. ON MONDAY THE LONGWAVE TROUGH WILL ENCOMPASS ALL BUT FL...STRETCHING FROM FAR N CANADA THROUGH QUEBEC...AND A SECONDARY LOW ACROSS THE PACIFIC NW. LOOK FOR PERSISTENT NW FLOW ALOFT WITH SEVERAL SMALL DISTURBANCES KEEPING OFF AND ON LES GOING OVER W UPPER MI...AND MAINLY E OF MUNISING ALONG LAKE SUPERIOR. THE FIRST OF MANY SHORTWAVES WILL BE IMPACTING OUR LOCAL WEATHER MONDAY...PUSHING ACROSS MN AND N MN MONDAY AFTERNOON...AND SINKING ACROSS UPPER MI LATE MONDAY AFTERNOON-MONDAY NIGHT. DURING THIS TIME 850MB TEMPS WILL ALSO DROP A COUPLE OF DEGREES C TOO FROM AN AVERAGE -18 TO -20. KEEPING THE THEME GOING...THE BACK EDGE OF THE 500MB TROUGH WILL TIGHTEN TO OUR NW ON TUESDAY IN RESPONSE TO THE N CANADIAN TROUGH SINKING/EXTENDING ACROSS E HUDSON BAY. THIS SHOULD BASICALLY ACT TO DOUBLE THE AMOUNT OF SNOW PLACES FAVORED BY THE NW WINDS...LIKE CMX WOULD HAVE OTHERWISE RECEIVED EVERY 6HRS. 850MB TEMPS WILL COOL ANOTHER COUPLE DEGREES C TO AROUND -22 BY 00Z WEDNESDAY. IT WILL BE A COLD DAY /SINGLE DIGITS TO MID TEENS/...FOLLOWED BY A COLD NIGHT. WITH SOME CLEARING IS ANTICIPATED S CENTRAL AND ALONG THE WI BORDER AS SFC WINDS BECOME MORE OUT OF THE W AND SW...-10C IS WELL WITHIN REACH. BRIEF WAA IS ANTICIPATED WEDNESDAY /NEW YEAR/S EVE/...WITH SNOW SHOWERS PUSHING OFF MUCH OF THE S SHORES OF LAKE SUPERIOR ON WSW WINDS. 850MB TEMPS SHOULD RISE TO AROUND -17C...OR EVEN WARMER AROUND -14C OFF THE 28/00Z GFS. THERE REMAINS SOME DISCREPANCIES ON THE TRACK/INTENSITY OF A SHORTWAVE THAT THE 27/00Z ECMWF HAS DIGGING ACROSS S LOWER MI BY 00Z THURSDAY...RESULTING IN MORE CLOUD COVER/LES SNOW AND COOLER CONDITIONS. THE GFS IS NOT TOO IMPRESSIVE...KEEPING MUCH OF THE ACTIVITY N OF THE CWA. WILL GO WITH A BLENDED/CONSENSUS SOLUTION FOR WEDNESDAY/WEDNESDAY NIGHT. BOTH THE GFS AND ECMWF INDICATE 45-60KT 850MB WINDS WEDNESDAY INTO EARLY THURSDAY...STRONGEST 18Z WEDNESDAY-12Z THURSDAY. OTHER THAN STRONG WINDS ACROSS LAKE SUPERIOR AND PORTIONS OF THE MORE EXPOSED KEWEENAW PENINSULA...IT IS UNKNOWN HOW MUCH OF THAT WILL BE ABLE TO MAKE IT TO THE SFC. ALSO DURING THIS TIME THE 500MB LOW OVER THE PACIFIC NW WILL HAVE SUNK ACROSS S CANADA...AND THE N LOW WILL HAVE SLID ACROSS MUCH OF HUDSON BAY. FRIDAY INTO SATURDAY LOOK A BIT MORE INTERESTING. THE GFS INDICATES THAT WE LOSE THE STRONG INVERSION THAT/S BASICALLY BEEN SET UP 800-850MB....AND PLENTY OF MOISTURE IN A BROAD DGZ STRETCHING FROM NEARLY 900-600MB. WILL BE INTERESTING TO WATCH THE EVOLUTION OF THIS SYSTEM...WITH THE 500MB LOW IN THE SW PUSHING ACROSS THE S PLAINS AND NUDGING A SFC LOW UP THE MS VALLEY...TO AROUND CENTRAL/S LOWER MI BY 18Z SATURDAY...THEN RAPIDLY DEEPENING ACROSS S ONTARIO AND QUEBEC SATURDAY NIGHT. THE 28/00Z HAS COME IN STRONGER AND FARTHER E WITH THE LOW COMPARED TO THE GFS. INCREASED POPS A BUT FRIDAY NIGHT GIVEN THE SOMEWHAT DECENT AGREEMENT...WITH FEW SIGNIFICANT CHANGES OTHERWISE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1250 PM EST SUN DEC 28 2014 A SURFACE TROUGH MOVING ACORSS CENTRAL UPPER MICHIGAN IS LEADING TO A BRIEF BAND OF LIGHT TO ALMOST MODERATE SNOW NEARING KSAW AT THE START OF THE TAF PERIOD. THIS WILL AFFECT THE SITE FOR THE FIRST 30-45 MINUTES AND THEN MOVE OFF TO THE EAST. BEHIND THE TROUGH...NORTHWEST FLOW LAKE EFFECT IS TAKING SHAPE OVER WESTERN LAKE SUPERIOR AND WILL BE THE MAIN ITEM OF CONCERN OVER THE NEXT 24 HOURS. OVERALL...WITH A STRONG INVERSION AROUND 4KFT ABOVE THE SURFACE...DON/T EXPECT THE SNOW SHOWERS TO BECOME TOO STRONG AND HAVE KEPT VISIBILITIES IN THE MVFR TO VFR RANGE AT KCMX/KIWD. LOW LEVEL WINDS DO LOOK TO BACK SLIGHTLY TONIGHT AHEAD OF A WEAK SURFACE TROUGH THAT WILL THEN SHIFT WINDS BACK TO THE NORTHWEST AROUND DAYBREAK. THUS...HAVE KEPT VSBYS A LITTLE HIGHER AT KIWD WITH THOSE BACKING WINDS. ONCE THAT WEAK TROUGH MOVES THROUGH...WOULD THINK THAT LIGHT LAKE EFFECT WOULD MOVE BACK INTO THE SITE. OTHERWISE...WITH THE UNFAVORABLE WIND DIRECTION FOR KSAW...EXPECT THEM TO TRANSITION TO VFR THIS AFTERNOON AND REMAIN THROUGH MUCH OF THE PERIOD (COULD SEE CEILINGS NEAR MVFR TOMORROW MORNING BEHIND THE TROUGH). && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 216 PM EST SUN DEC 28 2014 AS THE SURFACE TROUGH THAT SLID SOUTHEAST ACROSS LAKE SUPERIOR THIS MORNING CONTINUES SOUTHEAST THROUGH THE LOWER GREAT LAKES...PERSISTENT NORTHWEST WINDS OF 15-25KTS ARE EXPECTED OVER THE LAKE THROUGH TUESDAY. THIS IS DUE TO THE AREA BEING BETWEEN A STRONG HIGH MOVING INTO THE NORTHERN/CENTRAL PLAINS AND A LOW NEAR HUDSON BAY. A SURFACE TROUGH WILL SWEEP ACROSS LAKE SUPERIOR ON WEDNESDAY NIGHT AND TIGHTEN THE PRESSURE GRADIENT ACROSS THE LAKE. THIS IS EXPECTED TO PRODUCE WESTERLY GALES OF 35-40KTS WEDNESDAY INTO THURSDAY MORNING. WITH MUCH COLDER TEMPERATURES MOVING OVER LAKE SUPERIOR OVER THE NEXT SEVERAL DAYS...FREEZING SPRAY IS POSSIBLE FOR MUCH OF THE PERIOD. WITH THE STRONGER WINDS TUESDAY NIGHT INTO THURSDAY...HEAVY FREEZING SPRAY IS EXPECTED OVER MUCH OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KF AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1134 PM EST SAT DEC 27 2014 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 235 PM EST SAT DEC 27 2014 A COLD FRONT WILL MOVE THROUGH THIS EVENING. COLDER AIR WILL FOLLOW FOR THE REST OF THE WEEK WITH OCCASIONAL LAKE EFFECT SNOW SHOWERS. NO BIG STORMS ARE EXPECTED THROUGH NEW YEARS. && .UPDATE... ISSUED AT 931 PM EST SAT DEC 27 2014 A SECONDARY SURFACE TROUGH WAS NOTED AT 02Z FROM ROUGHLY ALPENA EXTENDING SW TO HARRISON AND LITTLE SABLE POINT. THIS FEATURE HAS BEEN THE IMPETUS FOR LIGHT RAIN AND SNOW NORTH AND WEST OF GRAND RAPIDS THIS EVENING DUE TO ENHANCED SURFACE CONVERGENCE. CONVERGENCE CAN BE SEEN IN THE 02Z METARS WITH NORTHWEST WINDS AT MBL AND CAD...WITH MORE WESTERLY FLOW FURTHER SOUTH. COLDER AIR IS ALSO EVIDENT INLAND AND BEHIND THIS SURFACE TROUGH WITH 32 AT CAD AND 33 AT HTL. HAVE SLIGHTLY INCREASED POPS BETWEEN 04-09Z IN WESTERN COUNTIES DUE TO DECENT LIFT IN THE CLOUD LAYER (MAINLY BELOW 5K FEET). TEMPERATURES ARE NOT QUITE COLD ENOUGH FOR DENDRITIC GROWTH...BUT AN ENHANCEMENT OF LIGHT MIXED PRECIP AND EVENTUALLY LIGHT SNOW IS POSSIBLE OVERNIGHT. STILL THOUGH...NOT MUCH IN THE WAY OF ACCUMULATIONS DUE TO WARM SURFACES AND AIR TEMPS REMAINING ABOVE FREEZING AS OF 0230Z. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 235 PM EST SAT DEC 27 2014 SFC LOW AND COLD FRONT MOVE EAST WITH RAIN SHOWERS ENDING. KEPT A SLIGHT CHANCE OF RAIN/SNOW SHOWERS THIS EVENING ACROSS THE NORTHWEST FORECAST AREA WHICH COULD BE CLIPPED BY THE SOUTHERN EDGE OF DEFORMATION ZONE PRECIP. THIS AREA COULD ALSO SEE SOME LAKE EFFECT SNOW SHOWERS LATER TONIGHT INTO SUNDAY MORNING. FLOW GOES NORTHWEST THIS EVENING WITH INVERSION HEIGHTS FALLING BLO 5 KFT...SO SNOW SHOWERS SHOULD BE LIGHT. SNOW SHOWERS SHOULD TAPER OFF SUNDAY MORNING AS DRYING AND SUBSIDENCE CONTINUE. SNOW SHOWERS COULD FLARE UP A BIT SUNDAY NIGHT AS AN ARCTIC FRONT SAGS SOUTH WITH SOME SFC CONVERGENCE HELPING THE CAUSE. THE FLOW GOES MORE NORTHERLY ON MONDAY BEHIND THE FRONT...SO ANY SNOW SHOWERS WILL BE CONFINED CLOSE TO THE COAST. SNOW SHOWERS COULD BE MOVING FURTHER INLAND LATE MONDAY NIGHT AS FLOW STARTS TO GO MORE NORTHWEST. INVERSION HEIGHTS ARE STILL AOB 5 KFT...SO ACCUMS WILL BE LIMITED. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 218 PM EST SAT DEC 27 2014 WE CONTINUE TO EXPECT A TREND TOWARD COLDER TEMPERATURES WITH CHCS OF LAKE EFFECT SNOW SHOWERS THROUGH MUCH OF THE LONG TERM. WE WILL THEN HAVE A CHC OF PCPN NEXT WEEKEND AS A STORM SYSTEM EJECTS FROM THE SW PORTION OF THE COUNTRY. NO REAL CHANGE TO THE TUE THROUGH THU TIMEFRAME WITH AN ARCTIC AIR MASS COMING IN ALONG WITH CHCS OF LIGHT LAKE EFFECT SNOW SHOWERS. THE RIDGE AXIS IN THE LOWER LEVELS WILL BE SHIFTING SOUTH OF THE AREA BY TUE. THIS WILL TRANSITION THE MEAN LOW LEVEL FLOW TO THE NW AND EVENTUALLY WEST. TEMPS AT H850 IN THE NEGATIVE TEENS C WILL BE SUFFICIENT FOR LAKE EFFECT. THE LAKE EFFECT IS NOT EXPECTED TO BE SIGNIFICANT AS THE NRN STREAM OF THE JET REMAINS NORTH...LEADING TO LO INVERSION HEIGHTS AND SHALLOW MOISTURE. A COUPLE OF SHORT WAVES WILL BE MOVING JUST NORTH OF THE CWFA TRYING TO HELP THE SNOW SHOWER CHCS OUT. IT LOOKS LIKE THE BRUNT OF THE SYSTEM THAT HAS BEEN SHOWN TO DEVELOP IN THE MODELS FOR NEXT WEEKEND WILL MISS MOST OF THE CWFA FOR NOW. THE TREND OVER THE PAST 24 HOURS IS FOR THE PARALLEL GFS AND EURO TO SLOW THE EJECTION OF THE SW ENERGY AS EXPECTED. THIS ALLOWS THE NRN STREAM OF THE JET TO MOVE IN AND SHUNT THE SRN STREAM SYSTEM TO THE SE. PLENTY OF TIME FOR THE MODELS TO RESOLVE THE INTERACTION OF THE TWO BRANCHES. FOR NOW WE WILL GO WITH A CHC OF SNOW AND FEATURE COOLER TEMPS COMPARED TO THE WARMER AND MORE WET SOLUTIONS OF THE PREVIOUS FEW DAYS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1132 PM EST SAT DEC 27 2014 MVFR CIGS PREVAIL ACROSS THE TAF SITES AT 0430Z. THERE IS A BAND OF RAIN/SNOW SHOWER MOVING SOUTH NEAR I-96. THIS BAND ON SHOWERS IS ASSOCIATED THE A SECONDARY COLD FRONT AND THIS FEATURE WILL MOVE QUICKLY SOUTH AND EAST OUT OF THE AREA. IT IS FOLLOWED NICELY VIA THE HRRR OVER THE PAST FEW HOURS OF RUNS. I HAVE TEMPO IFR SNOW SHOWERS AT GRR AND AZO FOR THIS BUT ONLY MVFR AT BTL. AFTER THAT MVFR CIGS WILL CONTINUE TILL MORNING. DRY AIR SHOULD CLEAR THE SKIES BY MID TO LATE MORNING. THIS CLEARING IS MOVING INTO EASTERN WISCONSIN NOW. ANOTHER WEAK COLD FRONT BRINGS MORE CLOUDS AND MAYBE SNOW SHOWERS MONDAY NIGHT. && .MARINE... ISSUED AT 328 AM EST SAT DEC 27 2014 A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH 11 AM SUNDAY. WINDS WILL VEER WEST TO 30 KNOTS THIS EVENING. WAVES WILL BUILD TO 4 TO 8 FEET NORTH OF HOLLAND AND 3 TO 5 FEET SOUTH OF HOLLAND. WEST WINDS WILL VEER NORTHWESTERLY OVERNIGHT. && .HYDROLOGY... ISSUED AT 328 AM EST SAT DEC 27 2014 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 11 AM EST SUNDAY FOR LMZ844>849. && $$ UPDATE...EBW SYNOPSIS...OSTUNO SHORT TERM...OSTUNO LONG TERM...NJJ AVIATION...WDM HYDROLOGY...EBW MARINE...EBW
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
933 PM CST MON DEC 29 2014 .UPDATE... EVENING SFC ANALYSIS INDICATES SFC HIGH PRESSURE BUILDING INTO OUR AREA. HRRR INDICATES CLOUDS WILL SLOWLY ERODE FROM THE N TONIGHT AS DRY AIR ADVECTION CONTINUES TO FILTER INTO OUR AREA. CLOUDS WILL BEGIN TO DRY OUT AFTER MIDNIGHT AND SHOULD BE SLOWLY MOVING TOWARDS/S OF THE I-20 CORRIDOR AFTER 12Z TUE. 00Z KLZK SOUNDING INDICATES FALLING PW`S AROUND 0.3-0.4 INCHES. IN AREAS ALONG/SE OF THE NATCHEZ TRACE WHERE DEWPOINTS WILL BE SLOWER TO FALL OVERNIGHT...EXPECT SOME PATCHY FOG TO BE POSSIBLE AS MID/UPPER LEVEL DRYING OVER THE THICK STRATUS DECK PROMOTES SOME STRATUS BUILDING DOWN INTO FOG. GFS-LAMP GUIDANCE INDICATES THIS IDEA AND THUS ADDED PATCHY FOG FROM 06Z-13Z. BUMPED UP LOWS A FEW DEGREES SE OF THE TRACE. ADJUSTED TEMP/DEWPOINT/SKY GRIDS TO CURRENT TRENDS. REST OF THE FORECAST IS ON TRACK. /DC/ && .AVIATION...MAINLY IFR TO LIFR FLIGHT CATS BEING EXPERIENCED AROUND THE REGION THIS EVENING...MAINLY DUE TO LOW CEILINGS. VISIBILITIES DUE TO DRIZZLE AND A BIT OF FOG ARE ALSO A BIT OF A CURRENT ISSUE AROUND PORTIONS OF CENTRAL AND EASTERN MS. EXPECTING FLIGHT CATS TO VERY GRADUALLY IMPROVE FROM NORTHWEST (GLH) TO SOUTHEAST (HBG) LATE TONIGHT THROUGH MIDDAY TUESDAY. HOWEVER...LOCATIONS SUCH AS HKS/JAN/NMM/MEI/GTR/CBM/PIB/HBG CAN STILL PROBABLY ANTICIPATE IFR CEILINGS AT DAYBREAK WITH TANGIBLE IMPROVEMENT MAINLY WAITING UNTIL AFTER THE SUN COMES UP. WINDS WILL RANGE FROM 5 TO 15 MPH FROM THE NORTH OVERNIGHT...BUT BY MID TO LATE MORNING SHOULD RANGE FROM 10 TO 20 MPH. /BB/ && .PREV DISCUSSION... /ISSUED 305 PM CST MON DEC 29 2014/ SHORT TERM...FORECAST PROBLEMS FOR THIS TIME PERIOD WILL BE PERSISTENT CLOUD DECK AND TEMP FORECAST TRANSITION WITH APPROACHING ARTIC AIRMASS. WHILE DEEP SW FLOW REMAINS IN PLACE OVER THE REGION...VEERING JUST A FEW DEGREES HAS ALLOWED DEEP MOISTURE TO MOVE OUT. WEAKER FLOW IN THE LAYER BELOW 800 MB HAS ALLOWED MOISTURE TO HANG AROUND. THAT COMBINED WITH LOCALIZED COOLING HAS ALLOWED RESULTING ISENTROPIC LIFT TO MAINTAIN CLOUD DECK AS WELL AS PRODUCE AREAS OF DRIZZLE THIS MORNING. INCREASING PRESSURE GRADIENT IN THE LOWER LEVELS TONIGHT WILL ALLOW FOR BETTER DOWNGLIDE AND SUPPORT A GRADUAL EROSION OF THE CLOUD DECK FROM THE NW AS THE FRINGES OF THE MODIFIED ARCTIC BEGIN TO IMPINGE ON THE AREA. EXPECT CLEAR SKIES BY TUESDAY AFTERNOON...BUT MAX TEMPS SHOULD BE SIMILAR TO TODAY IN INCREASED COLD AIR ADVECTION. STRONG MID/UPPER LEVEL STORM SYSTEM WILL CONTINUE TO DIVE SOUTH ALONG THE PAC COASTAL AREA AS SURFACE CENTER OF THE COLDER AIRMASS SETTLES OVER THE PLAINS BY WEDNESDAY. OUR PERIOD OF CLEAR SKIES AND DRY WEATHER WILL BE SHORT LIVED AS BACKING WINDS ALOFT BEGIN STREAMING MID/UPPER LEVEL CLOUDS BACK INTO THE AREA WEDNESDAY NIGHT/THURSDAY./26/ LONG TERM...THE LENGTHY PERIOD OF TIME THE WESTERN STORM SYSTEM WILL HAVE TAKEN BY THE TIME IT BEGINS TO IMPACT THE FORECAST AREA WILL HAVE GIVEN THE COLD AIRMASS TIME TO MODIFY SUBSTANTIALLY FROM WHAT IT WAS WHEN IT CAME THROUGH THE PLAINS. THUS...AM NOT EXPECTING A PROBLEM WITH WINTRY PRECIPITATION AT THE ONSET. PRECIPITATION LOOKS TO BEGIN AS LIGHT RAIN BY THURSDAY AFTERNOON AS WAA/ISENTROPIC ASCENT RESUME. THIS LIGHT STRATIFORM PRECIP REGIME SHOULD CONTINUE THROUGH THURSDAY NIGHT...BUT THINGS START CHANGING BY FRIDAY. AS THE MID/UPPER SYSTEM PULLS INTO THE PLAINS OF KS/N TX FRIDAY NIGHT/SATURDAY...SURFACE CYCLOGENESIS WILL GET UNDERWAY ALONG THE UPPER TX COASTAL BAROCLINIC ZONE. THIS LOW WILL RAPIDLY MOVE INLAND AND DRAG MID/UPPER 60S DEWPOINTS NORTHWARD TO AS FAR NORTH AS I20. WHILE INSTABILITY WILL INITIALLY BE ELEVATED...SURFACE BASED CONVECTION LOOKS PROBABLE BY SATURDAY AFTERNOON AS THE HIGH DEWPOINTS ARE BROUGHT NORTH. AT PRESENT...THE GFS IS SHOWING CAPES OF 500-1500 J/KG AND SRH FROM 250-300 M2/S2 OVER THE SOUTHERN HALF OF THE FORECAST AREA. WILL NEED TO MONITOR FUTURE MODEL RUNS CLOSELY TO SEE IF THIS POSSIBLE SEVERE SIGNAL CONTINUES./26/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 39 51 29 47 / 3 0 0 3 MERIDIAN 39 53 27 49 / 3 0 0 2 VICKSBURG 36 49 29 45 / 3 0 0 3 HATTIESBURG 45 56 31 52 / 7 0 0 3 NATCHEZ 39 50 29 47 / 3 0 0 4 GREENVILLE 32 46 27 40 / 3 0 0 3 GREENWOOD 32 47 27 44 / 3 0 0 3 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ DC/BB/26
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
212 PM EST SUN DEC 28 2014 .SYNOPSIS... A NORTHWEST FLOW OF COLD AIR WILL RETURN THE AREA TO MORE SEASONABLE WEATHER THIS WEEK. AS THIS AIR CROSSES THE GREAT LAKES IT WILL PICK UP SOME MOISTURE...SO A FEW LAKE EFFECT SNOW SHOWERS AND FLURRIES ARE POSSIBLE...ESPECIALLY OVER CENTRAL NEW YORK. && .NEAR TERM /THROUGH TONIGHT/... SOLID LL CLD DECK ALL THE WAY BACK INTO SW ONTARIO DESPITE THE NW FLOW OF DRIER AIR. XPCTY CONTD SLOW IMPRMT OVER NGT AS INCRSGLY DRIER AIR MVES INTO THE AREA. HRRR AND ARW DVLP SOME LGT LE LATE TNGT AS THE WLY DVLPS A SINGLE BAND INTO NRN ONEIDA AND PERHAPS XTRM NRN ONONDAGA. WITH MRGNL TEMPS AND WEAK LE XPCT ONLY TRACE AMTS. DESPITE THE COND CAA...OVRNGT TEMPS STILL WILL END UP ABV NRML FOR THE SEASON. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... CONTD WEAK LE EVENT PSBL WITH A SOMEWHAT SHEARED WNW FLOW AND MRGNL INSTABILITY. ISLTD LGT SNOW SHWRS PSBL OVER THE HIGHER TERRAIN MON AS HTG ADDS A BIT OF INSTBILITY OVER THE BARE GND. NAM FCST A WEAK SFC LOW TO DVLP OVRNGT MON WHICH REALLY JUST DISRUPTS THE BNDRY LYR FLOW WITHOUT ENHANCING THE LE. LTL CHG FOR TUE OTR THAN SLGTLY COLDER AIR IN PLACE AND PERHAPS A BIT BETTER ALIGNED LL FLOW. ALSO...HINT OF A SHRT WV MAY ENHANCE THE INSTABILITY LATE IN THE DAY. FLOW CONTS TO FAVOR ANY ACTIVITY TO BE OVER THE NRN THIRD OF THE FCST AREA. BEST CHANCE FOR LE WILL BE WED AS THE CONTD CAA HAS BROUGHT THE SNDG DEEPER INTO THE SNOW GROWTH ZONE AND FLOW BECOMES BETTER ALIGNED. WRKG AGAINST SIGNIFICANT ACCUMS WILL BE A CONSTANTLY CHGG MEAN FLOW AS A WV PASSES...AND YET ANOTHER APRCHS KICKING ANY BAND THAT DVLPS NORTH OF THE FCST AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... THE LONG TERM PERIOD BEGINS WITH A LARGE SCALE TROF ACROSS CENTRAL AND EASTERN CANADA. A COOL NORTHWEST FLOW WILL BRING LAKE EFFECT SNOW SHOWERS INTO NORTHERN NY INTO THURSDAY. A STORM SYSTEM MOVING OUT OF THE SOUTH CENTRAL UNITED STATES WILL SPREAD PRECIPITATION INTO NY/PA FRIDAY NIGHT. THE PRECIPITATION MAY ARRIVE AS LIGHT SNOW WITH POCKETS OF FREEZING RAIN. HOWEVER, ONCE THE WARM AIR PUSHES THROUGH THE REGION EARLY SATURDAY, TEMPERATURES WILL RISE INTO THE 40S AND THE PRECIPITATION WILL CHANGE TO RAIN. GENERALLY FOLLOWED HPC GUIDANCE WITH ADJUSTMENTS FOR LAKE EFFECT AREAS. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... WIDESPREAD MVFR CEILINGS WILL RISE SLIGHTLY THIS EVENING. CEILINGS OVERNIGHT ARE FORECAST TO RANGE FROM 2500 TO 4000 FEET, WITH NORTH-NORTHWEST WINDS AROUND 7 TO 10 KNOTS. SOME CLEARING IS POSSIBLE LATER MONDAY MORNING. THERE EXIST MODEL DIFFERENCES WITH RESPECT TO AMOUNT OF LOW LEVEL MOISTURE. GFS TRIES TO CLEAR SKIES OUT, WHEREAS NAM KEEPS MOISTURE LOCKED IN. LEANING TOWARD GFS AT THE MOMENT. OUTLOOK... MON...VFR. TUE/WED/THU...BRIEF RESTRICTIONS POSSIBLE AT TIMES FOR KRME/KSYR...DUE TO LAKE EFFECT -SHSN. OTRWS...VFR IS EXPECTED. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DGM NEAR TERM...DGM SHORT TERM...DGM LONG TERM...DJP AVIATION...DJP
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
939 AM EST SUN DEC 28 2014 .SYNOPSIS... HIGH PRESSURE WILL BE OVER THE AREA TONIGHT AND SUNDAY. A COLD FRONT WILL MOVE THROUGH EASTERN NORTH CAROLINA SUNDAY NIGHT AND MONDAY. HIGH PRESSURE WILL BE CENTERED IN THE VICINITY THROUGH THE REMAINDER OF THE WEEK...WITH A COLD FRONT APPROACHING NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 931 AM SUN...AREA OF LIGHT RAIN MOVING THROUGH THE COASTAL PLAINS THIS MORNING. AREA APPEARS TO BE MOSTLY VIRGA WITH DRY LAYER JUST ABOVE THE SURFACE...HOWEVER SOME STATIONS REPORTING LIGHT RAIN REACHING THE GROUND. SATELLITE PIX AND OBSERVATIONS SHOWING SKIES BECOMING MOSTLY CLOUDY WITH THICKER CLOUDS EXPECTED TO MOVE IN THROUGH THE DAY. HRRR INDICATING LOW CHANCES OF PRECIPITATION THROUGH THE DAY AS WEAK COASTAL TROUGH AND APPROACHING FRONT AFFECT THE AREA. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... AS OF 330 AM SUNDAY...THE MODELS DIFFER SLIGHTLY ON THE TIMING OF THE FRONT WITH THE NAM BEING THE QUICKEST TO PUSH IT THROUGH OVERNIGHT SUNDAY NIGHT. FAVORED A BLEND OF THE GFS/ECMWF/SREF AND PREVIOUS FCST FOR TIMING WHICH PUSHES THE FRONT TO ABOUT CAPE LOOKOUT BY MONDAY MORNING. THE CHANCE OF RAIN RAMPS UP TONIGHT...MOSTLY AFTER MIDNIGHT...BECOMING LIKELY TO CATEGORICAL BY MONDAY MORNING AS THE FRONT AND SHORTWAVE CROSSES THE AREA. LOWS SUNDAY NIGHT WILL BE MILD...IN THE UPPER 40S TO AROUND 50. && .LONG TERM /MONDAY THROUGH SATURDAY/... AS OF 4 AM SUN...A COLD FRONT WILL PUSH OFFSHORE MON MORNING AND STALL ACROSS THE OFFSHORE WATERS MON NIGHT AND TUES. BEST FORCING AND LIFT OCCUR AFTER FROPA WITH OVERRUNNING MOISTURE AND HAVE INCREASED POPS TO CATEGORICAL ALL BUT SOUTHERN COASTAL AREAS THROUGH THE MORNING HOURS...THEN SHIFT TO SOUTHERN COASTAL AREAS FOR THE AFTERNOON. QPF AMOUNTS WON`T BE TOO SIGNIFICANT...MAINLY LESS THAN AN HALF INCH. WEAK CAA AND A STRENGTHENING FRONTAL INVERSION ON MONDAY WILL MEAN A LOWERING OF CLOUDS AND WIDESPREAD LIGHT RAIN AND TEMPS STRUGGLING TO RISE WITH HIGHS RANGING FROM THE LOW/MID 50S NORTH TO UPR 50S SOUTH. A STRONG POST FRONTAL INVERSION WITH ABUNDANT LOW LEVEL MOISTURE CONTINUES MON NIGHT AND TUES AS WEAK LOW PRES DEVELOPS ALONG THE STALLED FRONTAL BOUNDARY OFFSHORE CONTINUING TO BRING LOW CLOUDS WITH PERIODS OF DRIZZLE OR LIGHT RAIN. DISCOUNTING THE NAM SOLUTION THIS PERIOD AS IT IS AN OUTLIER DEVELOPING STRONG LOW PRES AND MORE WIDESPREAD RAIN ACROSS THE REGION TUES. SHOULD BEGIN TO SEE IMPROVING CONDITIONS LATE TUES/TUES NIGHT AS DRIER AIR FILTERS IN WITH HIGH PRES BUILDING IN FROM THE WEST...HOWEVER THE NAM IS SLOWER IN DOING SO WITH LOW CLOUDS HANGING IN THROUGH TUES NIGHT. HIGHS TUES GENERALLY IN THE UPPER 40S/LOWER 50S. HIGH PRES BUILDS ACROSS THE AREA WED THROUGH FRI BRINGING DRY CONDITIONS AND SEASONABLY COOL CONDITIONS. WED WILL BE THE COOLEST DAY THIS PERIOD WITH HIGHS IN THE MID TO UPPER 40S...THEN WILL SEE THE AIRMASS GRADUALLY MODERATE THURS AND FRI WITH HIGHS IN THE 50S. LOWS WED AND THURS IN THE UPR 20S INLAND TO 30S COASTAL SECTIONS. INCREASING CLOUD COVER EXPECTED TO HOLD MINS TO THE 30S INLAND AND 40S COAST FRI. 00Z MODELS BEGINNING TO COME INTO BETTER AGREEMENT WITH THE LATE WEEK SYSTEM DEVELOPING ACROSS THE SOUTHERN PLAINS AND GULF STATES...AT LEAST TROUGH THE ONSET OF PRECIP LATE FRI INTO SAT. HIGH PRES SLIDES OFFSHORE FRI NIGHT WITH A COLD FRONT APPROACHING THE REGION SAT. WAA AND INCREASING MOISTURE COULD BRING A FEW SHOWERS ACROSS THE REGION LATE FRI/FRI NIGHT WITH INCREASING PRECIP CHANCES SAT. THE ECMWF IS MORE AMPLIFIED IN THE MID LEVELS AND SUBSEQUENTLY FASTER PUSHING THE FRONT AND PRECIP OFFSHORE SAT NIGHT WHILE THE GFS QUICKLY DAMPENS THE MID LEVEL TROUGH WITH THE FRONT STALLING ACROSS THE REGION LATE IN THE WEEKEND KEEPING PRECIP CHANCES IN THE FORECAST. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... SHORT TERM /THROUGH 06Z MONDAY/ AS OF 630 AM SUNDAY...HIGH CLOUDS OVER THE AREA WILL BEGIN TO THICKEN AND LOWER THROUGH THE DAY AS MOISTURE STREAMS ACROSS THE AREA AHEAD OF AN APPROACHING COLD FRONT. VFR CONDITIONS SHOULD PREVAIL THROUGH MOST OF THE AFTERNOON...BECOMING MVFR IN THE LATE AFTERNOON/EARLY EVENING AS CEILINGS LOWER. FOR THE MOST PART MOST OF THE DAY WILL REMAIN DRY WITH POSSIBLY A FEW LIGHT SPOTTY SHOWERS PUSHING INTO WESTERN AREAS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE BULK OF THE PRECIPITATION WILL HOLD OFF UNTIL AROUND AND AFTER MIDNIGHT. EXPECT WIDESPREAD MVFR CONDITIONS THIS EVENING AS SOME FOG DEVELOPS AS LOW LEVEL MOISTURE INCREASES TONIGHT AND CEILINGS CONTINUE TO LOWER. BY AFTER MIDNIGHT IFR CONDITIONS BECOME LIKELY ACROSS THE AREA AND RAIN WILL BECOME MORE WIDESPREAD BY THE END OF THE TAF PERIOD. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 4 AM SUN...A COLD FRONT WILL PUSH EAST OF RTES EARLY MON WITH OVERRUNNING MOISTURE CONTINUING TO BRING PERIODS OF RAIN WITH SUB VFR CONDITIONS THROUGH THE MORNING. BULK OF THE PRECIP PROGGED TO PUSH EAST OF THE TERMINALS MON AFTERNOON BUT EXEPCT IFR/LIFR STRATUS WITH AREAS OF DRIZZLE AND POSSIBLY OCCASIONAL PERIODS OF LIGHT RAIN CONTINUING INTO TUES. HIGH PRES BUILDS ACROSS THE AREA WED AND THURS WITH VFR CONDITIONS DOMINATING. && .MARINE... SHORT TERM /THROUGH TONIGHT/ AS OF 938 AM SUN...SOUTHWESTERLY FLOW OVER THE NORTH CAROLINA COASTAL WATERS THIS MORNING AROUND 10 KNOTS OR LESS WITH SEAS 2 TO 4 FEET. FRONT TO THE WEST WILL APPROACH THE WATERS THROUGH THE DAY. GRADIENT WILL TIGHTEN SOME AHEAD OF THE FRONT...BRINGING WINDS TO 10 TO 15 KNOTS DURING THE AFTERNOON. PREV DISC...AS OF 630 AM SUNDAY...NO SIGNIFICANT CHANGES THIS UPDATE. MODELS ARE IN PRETTY CLOSE AGREEMENT ON TIMING OF APPROACHING COLD FRONTAL PASSAGE COMING LATE MONDAY NIGHT. THE NAM WAS A BIT FASTER TO GET THE FRONT THROUGH THE ENTIRE AREA...BUT FOLLOWED A SLIGHTLY SLOWER BLEND OF THE GFS/ECMWF/SREF AND PREVIOUS FCST. SOUTHERLY FLOW WILL INCREASE TO AROUND 15 KT FOR THE COASTAL WATERS AHEAD OF THE FRONT TODAY. THE FRONT WILL MOVE INTO THE NORTHERN WATERS AFTER MIDNIGHT AND WILL BE DOWN NEAR CAPE LOOKOUT BY EARLY MONDAY MORNING. WINDS WILL LESSEN AS THE FRONT MOVES THROUGH THE AREA WITH A BIT OF A SURGE BEHIND THE FRONT COMING DURING THE DAY MONDAY. UNTIL THEN SEAS WILL REMAIN AROUND 2 TO 4 FEET FOR MOST OF THE WATERS. THE EXCEPTION MAY BE A SMALL AREA OF 5 FOOT SEAS IN THE CENTRAL WATERS AROUND DIAMOND BUOY TONIGHT INTO SUNDAY BEFORE THE FRONT MOVES INTO THE AREA AND SOUTHERLY WINDS LESSEN A BIT. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 4 AM SUN...A COLD FRONT WILL CONTINUE TO PUSH THROUGH THE SOUTHERN WATERS MON MORNING WITH N/NE WINDS INCREASING TO 10-20 KT AND SEAS BUILDING TO 3-5 FT ACROSS THE WATERS. THE FRONT IS PROGGED TO STALL ACROSS THE OFFSHORE WATERS MON NIGHT INTO EARLY TUES. WEAK LOW PRES DEVELOPS ALONG THE FRONT WITH STRONG HIGH PRES BUILDING IN FROM THE WEST TUES ALLOWING N/NE WINDS TO INCREASE TO 15-25 KT THROUGH TUES EVENING. SEAS BUILD TO 4-7 FT NORTH OF OCRACOKE AND 3-6 FT SOUTH TUES/TUES NIGHT IN RESPONSE. DISCOUNTING THE NAM SOLUTION TUES INTO WED AS IT IS AN OUTLIER DEVELOPING STRONGER LOW OFF THE COAST WITH WINDS NEAR GALE FORCE LATE TUES. WINDS AND SEAS GRADUALLY SUBSIDE LATE TUES NIGHT AND WED AS HIGH PRES BUILDS IN FROM THE WEST. N WINDS AOB 15 KT WED BECOMES WLY THURS. SEAS PROGGED TO SUBSIDE TO 2-5 FT WED AND 1-3 FT THURS. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...RSB NEAR TERM...CGG SHORT TERM...RSB LONG TERM...SK AVIATION...RSB/SK MARINE...CGG/RSB/SK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
340 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY... THEN PUSH SLOWLY SOUTHEAST THROUGH THE AREA MONDAY AND MONDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST LATE TUESDAY THROUGH THURSDAY. && .NEAR TERM /TONIGHT THROUGH SUNDAY/... AS OF 920 PM SATURDAY... SATELLITE CLOUD TRENDS SUPPORT EARLIER EXPECTATIONS OF CLOUDS OVERSPREADING CENTRAL NC FROM THE WEST AND SW... WITH CLOUDS STEADILY THICKENING AND LOWERING OVERNIGHT. THIS IS EXHIBITED WELL BY A COMPARISON OF THE 00Z GSO SOUNDING WITH UPSTREAM SOUNDINGS... WITH DRY AIR NEAR 500 MB AND BELOW 700 MB AND A PW NEAR 0.6 IN AT GSO... WHEREAS UPSTREAM LOCATIONS INCLUDING THE FFC AND BMX SOUNDINGS ARE MUCH WETTER THROUGH THE COLUMN... WITH PW VALUES 1.0- 1.5 IN... OVER 200% OF NORMAL... WHICH IS POISED TO ADVECT INTO NC. THE DEEPEST MOISTURE WAS OBSERVED OVER CENTRAL/SRN AL INTO CENTRAL GA... ASSOCIATED WITH A WEAK VORTICITY MAXIMUM... AND THIS IS ALSO WHERE REGIONAL RADAR SHOWS EXPANSIVE RAIN -- SOME OF IT MODERATE -- SPREADING TOWARD SOUTH CENTRAL NC... ALTHOUGH THE NE PROGRESSION OF THIS RAIN IS HINDERED BY INITIAL EVAPORATION ON ITS NE EDGE. NEVERTHELESS... RADAR TRENDS SUGGEST THAT THE SOUTHERN HALF OF THE CWA MAY SEE MEASURABLE RAIN FIRST... SIMILAR TO THE LATEST HRRR AND WRF-ARW RUNS. WE ALSO HAVE MUCH LOWER SURFACE DEWPOINTS IN THE NORTHERN CWA (UPPER 30S) AS COMPARED TO THE SOUTHERN AND EXTREME ERN CWA (LOW 40S)... AND THESE LOWER DEWPOINTS WILL TAKE LONGER TO BE OVERCOME. BASED ON THIS... HAVE MADE MINOR ADJUSTMENTS TO RAISE POPS A BIT LATE TONIGHT OVER THE SOUTH WITH A SMALL DOWNWARD TWEAK OF POPS IN THE NORTHWEST/NORTH CENTRAL... AND NO POPS NORTHEAST OF RALEIGH OVERNIGHT. MUCH OF WHAT WILL INITIALLY BE SEEN ON RADAR IN CENTRAL NC IS APT TO EVAPORATE PRIOR TO HITTING THE GROUND... BUT STILL EXPECT A LOW CHANCE OF MEASURABLE AMOUNTS TO SPREAD INTO THE SW CWA SOON AFTER MIDNIGHT... THEN EXPAND INTO THE REST OF THE WRN AND SRN CWA AFTER 3 AM. AMOUNTS WILL BE VERY LIGHT... A FUNCTION OF THE WEAK FORCING FOR ASCENT. AS ANTICIPATED EARLIER... TEMPS FELL MOST SOON AFTER NIGHTFALL AND HAVE LEVELED OFF SOMEWHAT... AND THE ENCROACHMENT OF CLOUDS WILL FURTHER BLANKET THE CWA OVERNIGHT... LIMITING TEMP FALL. EXPECT LOWS TO RANGE FROM THE LOWER 40S (NE) TO UPPER 40S (WEST). -GIH EARLIER DISCUSSION FROM 255 PM: LATEST SURFACE ANALYSIS SHOWS AN AREA OF SURFACE HIGH PRESSURE CENTERED NEAR THE NC/SC COAST ALONG THE COASTAL CAROLINAS AND VIRGINIA. A POSITIVELY TILTED DEAMPLIFYING UPPER TROUGH ACROSS THE WESTERN PLAINS AT MIDDAY TODAY WILL CONTINUE TO SHIFT SLOWLY EAST TODAY AND TONIGHT. THE NORTHERN PORTION OF THE TROUGH ASSOCIATED WITH THE NORTHERN JET STREAM WILL SHEAR EAST INTO THE EASTERN GREAT LAKES WHILE BY LATE SUNDAY AFTERNOON. THE SOUTHERN EXTENT OF THE TROUGH IS SHARPER AND MOVES SLOWLY EAST REACHING THE ARKLATEX BY SUNDAY EVENING. THE ASSOCIATED COLD FRONT WHICH EXTENDS FROM MICHIGAN SOUTHWEST TO EASTERN TX AT MIDDAY TODAY WILL MOVE EAST REACHING EASTERN PA AND NORTHWEST GA BY LATE SUNDAY AFTERNOON. MAINLY CLEAR SKIES ACROSS CENTRAL NC THIS AFTERNOON WILL GIVE WAY TO INCREASING HIGH AND MID CLOUDINESS THIS EVENING AS MOISTURE BEGINS TO INCREASE AHEAD OF THE FRONT. WHILE HIGH AND MID LEVEL CLOUDINESS WILL THICKEN OVERNIGHT... NAM/GFS/SREF BUFR SOUNDINGS ALL NOTE THAT THE LOWER THIRD OF THE TROPOSPHERE IS SLOW TO MOISTEN OVERNIGHT UNTIL LOW LEVEL MOISTURE SURGES INTO THE REGION FROM THE SOUTHWEST TOWARD DAYBREAK SUNDAY. THE PRECIPITATION IS LARGELY DRIVEN BY ISENTROPIC LIFT AROUND THE 295K SURFACE WITH THE BEST SURGE OF LIFT SKIRTING ACROSS THE NORTHWESTERN EDGE OF CENTRAL NC AND WILL ADVERTISE LOW CATEGORICAL POPS THERE. FORCING FOR ASCENT DECREASES TO THE SOUTH AND EAST ON SUNDAY WITH LOW CHANCE POPS ADVERTISED FOR THE SANDHILLS AND SOUTHERN COASTAL PLAIN. SO SUNDAY WILL FEATURE CLOUDY SKIES ACROSS CENTRAL NC IT WONT BE WASHOUT FOR EVERYONE. MAINLY SPOTTY LIGHT RAIN IS EXPECTED TO THE SOUTH AND SOUTHEAST OF RALEIGH WITH THE MOST WIDESPREAD RAIN EXPECTED NEAR AND ESPECIALLY TO THE NORTHWEST OF INTERSTATE 85. TEMPERATURES WILL BE A LITTLE TRICKY AS THEY WILL TEND TO FALL QUICKLY THIS EVENING AFTER SUNSET BUT THE OVERNIGHT TREND WILL BE COMPLICATED BY THE INCREASING MID AND HIGH CLOUDS AND THE LIGHT SOUTHERLY STIRRING AHEAD OF THE APPROACHING COLD FRONT. WILL FORECAST LOWS IN THE MID 40S WEST TO LOWER 40S EAST. HIGHS ON SUNDAY WILL BE COMPLICATED BY TE PRECIPITATION WHICH SHOULD KEEP HIGHS IN THE MID 50S ACROSS THE NORTHWEST PIEDMONT WITH MID 60S ACROSS THE SANDHILLS AND SOUTHERN COASTAL PLAIN WHERE THE RAIN WILL BE MORE SCATTERED. -BLAES && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS OF 330 PM SATURDAY... SUNDAY NIGHT...DEEP SW FLOW WILL MAINTAIN A MOIST AIR MASS ACROSS CENTRAL NC SUNDAY NIGHT INTO MONDAY MORNING. A STOUT DISTURBANCE ALOFT WILL APPROACH IN THE SW FLOW LATE SUNDAY AND CROSS OUR REGION EARLY MONDAY. MEANWHILE CENTRAL NC WILL BE IN THE RIGHT ENTRANCE REGION OF A 130-150KT JET. THE ENHANCED LIFT SUPPLIED BY BOTH THE JET AND THE APPROACHING DISTURBANCE INTERACTING WITH AN ABNORMALLY MOIST AIR MASS (PRECIP WATER VALUES PROJECTED TO BE 1-1.2 INCHES) WILL CAUSE RAIN TO BECOME WIDESPREAD LATE SUNDAY NIGHT INTO EARLY MONDAY. MIN TEMPS UPPER 40S FAR NORTH TO THE LOW-MID 50S FAR SOUTH. MONDAY... WIDESPREAD RAIN WILL DIMINISH IN COVERAGE AND INTENSITY BY MID DAY-EARLY AFTERNOON AS THE UPPER LEVEL DISTURBANCE AND THE JET DEPART OUR REGION. WHILE THE MID-UPPER LEVELS OF THE ATMOSPHERE WILL DRY OUT...SW FLOW IN THE 925-850MB LAYER WILL MAINTAIN SATURATION RESULTING IN OVERCAST SKIES WITH SPOTS OF RAIN AND/OR DRIZZLE. SURFACE COLD FRONT WILL DRAG SOUTHWARD ACROSS THE REGION AS THE UPPER DISTURBANCE PULLS OUT TO THE EAST-NE. A SHALLOW COLD AIR AIR MASS WILL INFILTRATE OUR REGION FROM THE NORTH. THIS SHOULD LEAD TO FALLING TEMPS BY LATE MORNING ACROSS THE NORTH...AND THE AFTERNOON ACROSS THE SOUTH. MONDAY NIGHT INTO TUESDAY...850MB TROUGH PROJECTED TO REMAIN WEST OF OUR REGION UNTIL MID DAY TUESDAY. THIS SUGGEST A CONTINUATION IN EXTENSIVE CLOUDINESS AND PATCHY LIGHT RAIN/DRIZZLE THROUGH THE MAJORITY OF MONDAY NIGHT. PASSAGE OF 850MB TROUGH AND ENSUING W-NW FLOW IN ITS WAKE ALONG WITH SUBSIDENCE WILL AID TO DISSIPATE CLOUD COVERAGE WEST-TO-EAST TUESDAY AFTERNOON. LOW LEVEL COLD AIR ADVECTION WILL RESULT IN A SMALLER THAN NORMAL DIURNAL TEMP RECOVERY. MIN TEMPS MID-UPPER 40S NORTH TO LOWER 40S SOUTH. MAX TEMPS TUESDAY MID 40S NORTH TO NEAR 50 SOUTH. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 340 AM SUNDAY... TUE: A WELL-DEFINED SHORTWAVE TROUGH OVER WA THIS MORNING WILL AMPLIFY ACROSS THE ROCKIES THROUGH TONIGHT...THEN DEAMPLIFY FROM THE CENTRAL PLAINS TO THE MIDDLE ATLANTIC COAST TUE THROUGH TUE NIGHT. THE PASSAGE OF THIS FEATURE AND ASSOCIATED GLANCING BLOW OF THE SOUTHERN PERIPHERY OF HEIGHT FALLS ALOFT...AND ASSOCIATED FORCING FOR ASCENT...WILL PRODUCED RENEWED LIFT ATOP A STILL-SATURATED LAYER IN ROUGHLY THE LOWEST SEVERAL THOUSAND FT --DEEPEST NEAR THE VA BORDER/IN CLOSEST PROXIMITY TO THE STRONGEST HEIGHT FALLS ALOFT OVER THE MIDDLE ATLANTIC-- SUCH THAT OTHERWISE PERIODS OF DRIZZLE THROUGH EARLY TUE WILL BECOME LIGHT RAIN DURING THE MORNING TO MIDDAY HOURS. BEHIND THE PASSING SHORTWAVE TROUGH...NW 925-850 MB FLOW WILL PROMOTE BOTH DOWNSLOPE FLOW AND A DISSIPATION OF THE CAD INVERSION VIA CAA - BOTH MECHANISMS THAT SHOULD SERVE TO SCOUR THE CAD REGIME AND PROMOTE CLEARING BY THE AFTERNOON OR EVENING. THE TIMING OF THIS PROCESS REMAINS IN QUESTION OWING TO TIMING DIFFERENCES AMONGST NWP GUIDANCE REGARDING THE PASSAGE OF THE SHORTWAVE TROUGH...THOUGH THERE HAS BEEN AN OVERALL SLOWER TREND EVIDENT IN THE GUIDANCE. AS SUCH...WILL FAVOR A SLOWER CLEARING TREND FROM WEST TO EAST SUCH THAT TEMPERATURES LIKELY WILL NOT HAVE TIME TO RESPOND TO THE SETTING AFTERNOON SUN...WHICH WOULD RESULT IN HIGHS ONLY IN THE LOWER TO MIDDLE 40S. IF A FEW HOUR PERIOD OF SUN DOES MATERIALIZE... MOST LIKELY OVER THE SOUTHERN AND WESTERN PIEDMONT DURING THE AFTERNOON...TEMPERATURES WOULD RESPOND TO NEAR NORMAL VALUES IN THE UPPER 40S. TUE NIGHT-SAT: STRONG...ARCTIC HIGH PRESSURE OVER THE ROCKIES EARLY IN THE PERIOD WILL OTHERWISE SPRAWL EAST ACROSS THE MIDDLE ATLANTIC AND SOUTHEAST STATES...THROUGH THU...BENEATH GENERALLY WESTERLY FLOW BETWEEN CONFLUENT BRANCHES OF THE UPPER JET...BEFORE DRIFTING OFFSHORE AHEAD OF AN EJECTING DESERT SW (BRIEFLY) CUTOFF LOW FRI- SAT. THE RESULT WILL BE COOL CONDITIONS --MOST NOTABLY WED AND THU MORNINGS WHEN TEMPERATURES SHOULD DIP WELL INTO THE 20S (WITH UPPER TEENS POSSIBLE IN OUTLYING AREAS THAT EXPERIENCE CALM) GIVEN PROJECTED LOW LEVEL THICKNESS VALUES IN THE 1290-1300 METER RANGE. IT WILL ALSO BE CLEAR OR MOSTLY SO DURING MOST OF THE PERIOD...WITH THE EXCEPTION OF A PERIOD OF PASSING MID-HIGH CLOUDS IN ASSOCIATION WITH A STRONGLY-SHEARED AND POSITIVELY-TILTED TRAILING SHORTWAVE TROUGH DURING THE DAY WED. WHILE MEDIUM RANGE GUIDANCE DIVERGES WITH RESPECT TO THE EJECTION OF THE AFOREMENTIONED DESERT SW LOW AND ASSOCIATED APPROACH OF THE NEXT FRONTAL SYSTEM...THE OVERALL PATTERN (WITH TIMING DIFFERENCES TO BE WORKED OUT) WOULD RESULT IN A LOW TRACK TO THE NW OF CENTRAL NC AND AN ASSOCIATED WARM FRONTAL PASSAGE IN RETURN FLOW AROUND THE DEPARTING AND MODIFIED ARCTIC HIGH --TIMING MOST LIKELY FRI NIGHT- SAT FAVORED (DUE TO TYPICAL FAST BIAS IN NWP WITH SW CUTOFFS) AS DEPICTED BY THE SLOWER EC AND EC MEAN. IF SHOWERS OCCUR WITH THE PASSAGE OF THE WARM FRONT...MOST LIKELY OVER THE WESTERN PIEDMONT... AN IN-SITU DAMMING EVENT WOULD EVOLVE INTO THE EARLY PART OF THE WEEKEND...IN A PATTERN OTHERWISE SUPPORTIVE OF WARMING TEMPERATURES OVER THE SE CONUS. AS SUCH...TEMPERATURES ON SAT ARE APT TO DISPLAY A WIDER THAN AVG RANGE OVER CENTRAL NC...WITH MARKEDLY COOLER TEMPERATURES OVER THE NW PIEDMONT. && .AVIATION /06Z SUNDAY THROUGH WEDNESDAY/... AS OF 115 AM SUNDAY... AN AREA OF LIGHT RAIN ASSOCIATED WITH WEAK UPPER LEVEL DISTURBANCE WILL BRING SOME SUB-VFR CONDITIONS TO CENTRAL NC TODAY. HOWEVER...GIVEN THE AMOUNT OF DRY AIR STILL IN PLACE OVER THE AREA...THERE REMAIN UNCERTAINTY REGARDING HOW MUCH RAIN WILL FALL AND HOW LOW CEILINGS WILL DROP. WHILE A FEW SPRINKLES ARE POSSIBLE THROUGH 12Z...CEILINGS WILL MOSTLY REMAIN AT OR ABOVE 10K FT. BETTER MOISTURE IS STILL EXPECTED TO SPREAD UP ACROSS THE WESTERN PIEDMONT...WHERE THERE IS A BETTER CHANCE OF MORE STEADY RAIN AND CEILINGS IN THE MVFR OR IFR RANGE IN THE 12Z TO 21Z TIME FRAME. TO THE EAST...WHERE SUPPORT FOR PRECIP IS WEAKER...CONFIDENCE IN MVFR CEILINGS IS LOWER...AND SOME GUIDANCE SUGGESTS CEILINGS MAY REMAIN VFR THROUGH MIDDAY FROM KRDU EASTWARD. EXPECT THE LIGHT RAIN TO THEN BE INTERMITTENT LATER THIS AFTERNOON AS A LULL DEVELOPS...WITH A PERIOD OF VFR CONDITIONS POSSIBLE BEFORE A COLD FRONT PUSHES INTO THE AREA FROM THE NORTH TONIGHT. WINDS WILL BE 5-10KT OUT OF THE SOUTHWEST TODAY...TURNING TO NORTHWESTERLY AND THEN NORTHERLY BEHIND THE FRONT TONIGHT. LOOKING AHEAD: CEILINGS WILL REDEVELOP MONDAY AS STRENGTHENING SOUTHERLY FLOW ATOP THE SOUTHWARD SINKING COLD FRONT LEADS TO WIDESPREAD RAIN. THESE LOW CEILINGS...ALONG WITH SOME PERIODS OF LIGHT RAIN OR DRIZZLE WILL LINGER THROUGH MONDAY NIGHT...WITH CONDITIONS EXPECTED TO IMPROVE TUESDAY && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BLAES SHORT TERM....WSS LONG TERM...MWS AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
115 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY... THEN PUSH SLOWLY SOUTHEAST THROUGH THE AREA MONDAY AND MONDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST LATE TUESDAY THROUGH THURSDAY. && .NEAR TERM /TONIGHT THROUGH SUNDAY/... AS OF 920 PM SATURDAY... SATELLITE CLOUD TRENDS SUPPORT EARLIER EXPECTATIONS OF CLOUDS OVERSPREADING CENTRAL NC FROM THE WEST AND SW... WITH CLOUDS STEADILY THICKENING AND LOWERING OVERNIGHT. THIS IS EXHIBITED WELL BY A COMPARISON OF THE 00Z GSO SOUNDING WITH UPSTREAM SOUNDINGS... WITH DRY AIR NEAR 500 MB AND BELOW 700 MB AND A PW NEAR 0.6 IN AT GSO... WHEREAS UPSTREAM LOCATIONS INCLUDING THE FFC AND BMX SOUNDINGS ARE MUCH WETTER THROUGH THE COLUMN... WITH PW VALUES 1.0- 1.5 IN... OVER 200% OF NORMAL... WHICH IS POISED TO ADVECT INTO NC. THE DEEPEST MOISTURE WAS OBSERVED OVER CENTRAL/SRN AL INTO CENTRAL GA... ASSOCIATED WITH A WEAK VORTICITY MAXIMUM... AND THIS IS ALSO WHERE REGIONAL RADAR SHOWS EXPANSIVE RAIN -- SOME OF IT MODERATE -- SPREADING TOWARD SOUTH CENTRAL NC... ALTHOUGH THE NE PROGRESSION OF THIS RAIN IS HINDERED BY INITIAL EVAPORATION ON ITS NE EDGE. NEVERTHELESS... RADAR TRENDS SUGGEST THAT THE SOUTHERN HALF OF THE CWA MAY SEE MEASURABLE RAIN FIRST... SIMILAR TO THE LATEST HRRR AND WRF-ARW RUNS. WE ALSO HAVE MUCH LOWER SURFACE DEWPOINTS IN THE NORTHERN CWA (UPPER 30S) AS COMPARED TO THE SOUTHERN AND EXTREME ERN CWA (LOW 40S)... AND THESE LOWER DEWPOINTS WILL TAKE LONGER TO BE OVERCOME. BASED ON THIS... HAVE MADE MINOR ADJUSTMENTS TO RAISE POPS A BIT LATE TONIGHT OVER THE SOUTH WITH A SMALL DOWNWARD TWEAK OF POPS IN THE NORTHWEST/NORTH CENTRAL... AND NO POPS NORTHEAST OF RALEIGH OVERNIGHT. MUCH OF WHAT WILL INITIALLY BE SEEN ON RADAR IN CENTRAL NC IS APT TO EVAPORATE PRIOR TO HITTING THE GROUND... BUT STILL EXPECT A LOW CHANCE OF MEASURABLE AMOUNTS TO SPREAD INTO THE SW CWA SOON AFTER MIDNIGHT... THEN EXPAND INTO THE REST OF THE WRN AND SRN CWA AFTER 3 AM. AMOUNTS WILL BE VERY LIGHT... A FUNCTION OF THE WEAK FORCING FOR ASCENT. AS ANTICIPATED EARLIER... TEMPS FELL MOST SOON AFTER NIGHTFALL AND HAVE LEVELED OFF SOMEWHAT... AND THE ENCROACHMENT OF CLOUDS WILL FURTHER BLANKET THE CWA OVERNIGHT... LIMITING TEMP FALL. EXPECT LOWS TO RANGE FROM THE LOWER 40S (NE) TO UPPER 40S (WEST). -GIH EARLIER DISCUSSION FROM 255 PM: LATEST SURFACE ANALYSIS SHOWS AN AREA OF SURFACE HIGH PRESSURE CENTERED NEAR THE NC/SC COAST ALONG THE COASTAL CAROLINAS AND VIRGINIA. A POSITIVELY TILTED DEAMPLIFYING UPPER TROUGH ACROSS THE WESTERN PLAINS AT MIDDAY TODAY WILL CONTINUE TO SHIFT SLOWLY EAST TODAY AND TONIGHT. THE NORTHERN PORTION OF THE TROUGH ASSOCIATED WITH THE NORTHERN JET STREAM WILL SHEAR EAST INTO THE EASTERN GREAT LAKES WHILE BY LATE SUNDAY AFTERNOON. THE SOUTHERN EXTENT OF THE TROUGH IS SHARPER AND MOVES SLOWLY EAST REACHING THE ARKLATEX BY SUNDAY EVENING. THE ASSOCIATED COLD FRONT WHICH EXTENDS FROM MICHIGAN SOUTHWEST TO EASTERN TX AT MIDDAY TODAY WILL MOVE EAST REACHING EASTERN PA AND NORTHWEST GA BY LATE SUNDAY AFTERNOON. MAINLY CLEAR SKIES ACROSS CENTRAL NC THIS AFTERNOON WILL GIVE WAY TO INCREASING HIGH AND MID CLOUDINESS THIS EVENING AS MOISTURE BEGINS TO INCREASE AHEAD OF THE FRONT. WHILE HIGH AND MID LEVEL CLOUDINESS WILL THICKEN OVERNIGHT... NAM/GFS/SREF BUFR SOUNDINGS ALL NOTE THAT THE LOWER THIRD OF THE TROPOSPHERE IS SLOW TO MOISTEN OVERNIGHT UNTIL LOW LEVEL MOISTURE SURGES INTO THE REGION FROM THE SOUTHWEST TOWARD DAYBREAK SUNDAY. THE PRECIPITATION IS LARGELY DRIVEN BY ISENTROPIC LIFT AROUND THE 295K SURFACE WITH THE BEST SURGE OF LIFT SKIRTING ACROSS THE NORTHWESTERN EDGE OF CENTRAL NC AND WILL ADVERTISE LOW CATEGORICAL POPS THERE. FORCING FOR ASCENT DECREASES TO THE SOUTH AND EAST ON SUNDAY WITH LOW CHANCE POPS ADVERTISED FOR THE SANDHILLS AND SOUTHERN COASTAL PLAIN. SO SUNDAY WILL FEATURE CLOUDY SKIES ACROSS CENTRAL NC IT WONT BE WASHOUT FOR EVERYONE. MAINLY SPOTTY LIGHT RAIN IS EXPECTED TO THE SOUTH AND SOUTHEAST OF RALEIGH WITH THE MOST WIDESPREAD RAIN EXPECTED NEAR AND ESPECIALLY TO THE NORTHWEST OF INTERSTATE 85. TEMPERATURES WILL BE A LITTLE TRICKY AS THEY WILL TEND TO FALL QUICKLY THIS EVENING AFTER SUNSET BUT THE OVERNIGHT TREND WILL BE COMPLICATED BY THE INCREASING MID AND HIGH CLOUDS AND THE LIGHT SOUTHERLY STIRRING AHEAD OF THE APPROACHING COLD FRONT. WILL FORECAST LOWS IN THE MID 40S WEST TO LOWER 40S EAST. HIGHS ON SUNDAY WILL BE COMPLICATED BY TE PRECIPITATION WHICH SHOULD KEEP HIGHS IN THE MID 50S ACROSS THE NORTHWEST PIEDMONT WITH MID 60S ACROSS THE SANDHILLS AND SOUTHERN COASTAL PLAIN WHERE THE RAIN WILL BE MORE SCATTERED. -BLAES && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... AS OF 330 PM SATURDAY... SUNDAY NIGHT...DEEP SW FLOW WILL MAINTAIN A MOIST AIR MASS ACROSS CENTRAL NC SUNDAY NIGHT INTO MONDAY MORNING. A STOUT DISTURBANCE ALOFT WILL APPROACH IN THE SW FLOW LATE SUNDAY AND CROSS OUR REGION EARLY MONDAY. MEANWHILE CENTRAL NC WILL BE IN THE RIGHT ENTRANCE REGION OF A 130-150KT JET. THE ENHANCED LIFT SUPPLIED BY BOTH THE JET AND THE APPROACHING DISTURBANCE INTERACTING WITH AN ABNORMALLY MOIST AIR MASS (PRECIP WATER VALUES PROJECTED TO BE 1-1.2 INCHES) WILL CAUSE RAIN TO BECOME WIDESPREAD LATE SUNDAY NIGHT INTO EARLY MONDAY. MIN TEMPS UPPER 40S FAR NORTH TO THE LOW-MID 50S FAR SOUTH. MONDAY... WIDESPREAD RAIN WILL DIMINISH IN COVERAGE AND INTENSITY BY MID DAY-EARLY AFTERNOON AS THE UPPER LEVEL DISTURBANCE AND THE JET DEPART OUR REGION. WHILE THE MID-UPPER LEVELS OF THE ATMOSPHERE WILL DRY OUT...SW FLOW IN THE 925-850MB LAYER WILL MAINTAIN SATURATION RESULTING IN OVERCAST SKIES WITH SPOTS OF RAIN AND/OR DRIZZLE. SURFACE COLD FRONT WILL DRAG SOUTHWARD ACROSS THE REGION AS THE UPPER DISTURBANCE PULLS OUT TO THE EAST-NE. A SHALLOW COLD AIR AIR MASS WILL INFILTRATE OUR REGION FROM THE NORTH. THIS SHOULD LEAD TO FALLING TEMPS BY LATE MORNING ACROSS THE NORTH...AND THE AFTERNOON ACROSS THE SOUTH. MONDAY NIGHT INTO TUESDAY...850MB TROUGH PROJECTED TO REMAIN WEST OF OUR REGION UNTIL MID DAY TUESDAY. THIS SUGGEST A CONTINUATION IN EXTENSIVE CLOUDINESS AND PATCHY LIGHT RAIN/DRIZZLE THROUGH THE MAJORITY OF MONDAY NIGHT. PASSAGE OF 850MB TROUGH AND ENSUING W-NW FLOW IN ITS WAKE ALONG WITH SUBSIDENCE WILL AID TO DISSIPATE CLOUD COVERAGE WEST-TO-EAST TUESDAY AFTERNOON. LOW LEVEL COLD AIR ADVECTION WILL RESULT IN A SMALLER THAN NORMAL DIURNAL TEMP RECOVERY. MIN TEMPS MID-UPPER 40S NORTH TO LOWER 40S SOUTH. MAX TEMPS TUESDAY MID 40S NORTH TO NEAR 50 SOUTH. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 330 PM SATURDAY... WEDNESDAY THROUGH SATURDAY... A BROAD UPPER LEVEL TROUGH WILL COVER THE BULK OF THE U.S. THIS PERIOD WITH A CLOSED UPPER LEVEL LOW PROJECTED TO EDGE SLOWLY EAST ACROSS THE SW U.S-SOUTHERN ROCKIES. MODEL GUIDANCE TRADITIONALLY HAVE TROUBLE TIMING THE MOVEMENT OF THESE CLOSED LOWS INT EH SW. USUALLY...SLOWER IS BETTER. FOR CENTRAL NC...EXPECT DRY CONDITIONS THROUGH AT LEAST FRIDAY AND POSSIBLY INTO SATURDAY WITH TEMPS BELOW NORMAL AT MID WEEK...MODERATING TO NEAR NORMAL LEVELS BY THE WEEKEND. A S/W WILL CROSS THE MID ATLANTIC LATE WEDNESDAY-WEDNESDAY NIGHT...ACCOMPANIED BY A DRY SFC FRONT PASSAGE. FLOW BEHIND THIS FEATURE WILL REINFORCE THE COOL AIR IN PLACE. MAX TEMPS WILL AVERAGE 4-6 DEGREES BELOW NORMAL WEDNESDAY-FRIDAY WHILE OVERNIGHT LOWS IN THE 20S WILL BE COMMON. TIMING DIFFERENCES IN THE MODELS BY NEXT WEEKEND PLAY HAVOC WITH PRECIP CHANCES AND TEMP FORECAST. PERSISTENT WLY FLOW SHOULD LEAD TO MODIFICATION OF THE AIR MASS...LEADING TO TEMPS AT OR ABOVE NORMAL. IF PRECIP DELAYED UNTIL LATE SATURDAY OR SATURDAY NIGHT...POTENTIAL FOR TEMPS TO BE WELL ABOVE NORMAL. && .AVIATION /06Z SUNDAY THROUGH WEDNESDAY/... AS OF 115 AM SUNDAY... AN AREA OF LIGHT RAIN ASSOCIATED WITH WEAK UPPER LEVEL DISTURBANCE WILL BRING SOME SUB-VFR CONDITIONS TO CENTRAL NC TODAY. HOWEVER...GIVEN THE AMOUNT OF DRY AIR STILL IN PLACE OVER THE AREA...THERE REMAIN UNCERTAINTY REGARDING HOW MUCH RAIN WILL FALL AND HOW LOW CEILINGS WILL DROP. WHILE A FEW SPRINKLES ARE POSSIBLE THROUGH 12Z...CEILINGS WILL MOSTLY REMAIN AT OR ABOVE 10K FT. BETTER MOISTURE IS STILL EXPECTED TO SPREAD UP ACROSS THE WESTERN PIEDMONT...WHERE THERE IS A BETTER CHANCE OF MORE STEADY RAIN AND CEILINGS IN THE MVFR OR IFR RANGE IN THE 12Z TO 21Z TIME FRAME. TO THE EAST...WHERE SUPPORT FOR PRECIP IS WEAKER...CONFIDENCE IN MVFR CEILINGS IS LOWER...AND SOME GUIDANCE SUGGESTS CEILINGS MAY REMAIN VFR THROUGH MIDDAY FROM KRDU EASTWARD. EXPECT THE LIGHT RAIN TO THEN BE INTERMITTENT LATER THIS AFTERNOON AS A LULL DEVELOPS...WITH A PERIOD OF VFR CONDITIONS POSSIBLE BEFORE A COLD FRONT PUSHES INTO THE AREA FROM THE NORTH TONIGHT. WINDS WILL BE 5-10KT OUT OF THE SOUTHWEST TODAY...TURNING TO NORTHWESTERLY AND THEN NORTHERLY BEHIND THE FRONT TONIGHT. LOOKING AHEAD: CEILINGS WILL REDEVELOP MONDAY AS STRENGTHENING SOUTHERLY FLOW ATOP THE SOUTHWARD SINKING COLD FRONT LEADS TO WIDESPREAD RAIN. THESE LOW CEILINGS...ALONG WITH SOME PERIODS OF LIGHT RAIN OR DRIZZLE WILL LINGER THROUGH MONDAY NIGHT...WITH CONDITIONS EXPECTED TO IMPROVE TUESDAY && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/BLAES SHORT TERM....WSS LONG TERM...WSS AVIATION...BLS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
330 PM EST SUN DEC 28 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE REGION FROM THE WEST TONIGHT AND INTO TUESDAY. A COLD FRONT WILL SAG SOUTH ACROSS THE REGION LATER TUESDAY. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION FROM THE SOUTHWEST THE SECOND HALF OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS FEARED CLOUDS HAVE BEEN SLOW TO EXIT THE AREA. STILL SEEING LOW CIGS IN NW OHIO THIS AFTERNOON WITH A SWATCH OF HIGH CLOUDS ABOVE AS WELL. DRIER AIR AND HIGH PRESSURE WILL GRADUALLY WIN OUT OVERNIGHT AND WILL STILL TRY TO TAKE THE SW HALF OF THE AREA TO PARTLY CLOUDY OVERNIGHT. FORECAST SOUNDINGS AND THE LATEST HRRR CONTINUE TO HINT AT SOME LIGHT SNOW OVER NW PA TONIGHT AS LOW LEVEL MOISTURE PERSISTS A WHILE LONGER. 850 MB TEMPS WILL DIP TO NEG 9 OR SO BY MORNING SO WILL INTRODUCE A SMALL 20 POP FOR SNOW SHOWERS. NOT EXPECTING ANY ACCUMULATION AND REALISTICALLY PROBABLY NOT MUCH MORE THAN FLURRIES. THE EVENING CREW WILL HAVE TO WATCH TEMPS...IF THE CLOUDS LINGER...FORECAST LOWS WILL NEED TO BE NUDGED UP. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... ALL IN ALL IT SHOULD BE A QUIET PERIOD AS A STRONG AREA OF HIGH PRESSURE EXERTS ITSELF OVER THE REGION. MAY BE SOME LINGERING FLURRIES AT DAYBREAK OVER NW PA BUT THOSE SHOULD END QUICKLY AS DRIER AIR SETTLES IN FROM THE NORTH. WILL SEE ANOTHER COLD FRONT SAG SOUTH ACROSS THE AREA SOMETIME LATE TUESDAY. AT THAT POINT TEMPS WILL REALLY TAKE A DOWNWARD TURN. MOISTURE BEHIND THE FRONT IS LACKING BUT GIVEN LAKE TO 850 MB TEMPERATURE DIFFERENCES APPROACHING 20 DEGREES...THERE SHOULD BE AT LEAST A FEW SNOW SHOWERS FROM KCLE EAST TUESDAY NIGHT AND WEDNESDAY. FORECAST SOUNDINGS INITIALLY SHOW A CAPPING INVERSION OF 6 TO 7K FEET BUT THIS WILL LOWER ON WEDNESDAY. MOISTURE APPEARS TO BE LACKING AS WELL SO NOT EXPECTING ANY HEADLINES AND PROBABLY NO MORE THAN A COUPLE INCHES OF SNOW EVEN IN PREFERRED AREA. SNOW CHANCES WILL BEGIN TO DIMINISH BY WEDNESDAY EVENING AS THE FLOW BEGINS TO PUSH ANY SNOW BANDS NORTH ONTO LAKE ERIE. HAVE CONTINUED THE RECENT TREND OF NUDGING TEMPS DOWN SLIGHTLY FOR THE MIDDLE PART OF THE WEEK. TEMPS MONDAY WILL BE SEASONABLE BUT BY WEDNESDAY READINGS WILL STRUGGLE TO GET MUCH ABOVE 20 DEGREES FOR HIGHS. THE NEW GUIDANCE SEEMS TO HAVE A FAIRLY GOOD HANDLE ON THIS AND HAVE USED A BLEND OF GUIDANCE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... FORECAST DURING THIS PERIOD IS RATHER COMPLICATED WITH LOWER CONFIDENCE. THE MODELS HAVE SOME DIFFERENCES IN THE PHASING OF THE SPLIT FLOW OVER THE NATION AND THE TREATMENT OF THE SHORT WAVE IN THE SOUTHERN STREAM. THE GFS DEVELOPS A LOW PRESSURE OVER THE MISSISSIPPI VALLEY AND TRACKS IT WEST OF THE REGION TO PRODUCE RAIN OVER THE AREA ON THE SATURDAY AS IT PHASES THE SOUTHERN STREAM SHORT WAVE IN THE NORTHERN JET STREAM. THE ECMWF DOES NOT PHASE THE SOUTHERN SHORT WAVE WITH THE NORTHERN STREAM AND SLOWS DOWN THE FEATURE AND TRACKS IT SOUTH OF THE REGION. THIS KEEPS THE REGION COLD WITH LIGHT SNOW EXPECTED. FOR THE MOST PART HAVE TAKEN A COMPROMISED SOLUTION BETWEEN THE TWO MODELS WITH MIXED PRECIPITATION FORECASTED. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... GRADUAL IMPROVEMENT IN CEILING HEIGHT IS EXPECTED THIS AFTERNOON AND EVENING MAINLY AWAY FROM LAKE ERIE. WIDELY SCATTERED LIGHT RA-/SN- FROM GEAUGA COUNTY TO YNG SHOULD END BY THE MIDDLE OF THE AFTERNOON. EXPECT A SCATTERING OUT OF LOW CLOUDS WEST OF CLE TOWARD SUNSET WITH CEILINGS GENERALLY LIFTING TO THE 2500-3500FT RANGE FROM MFD TO CLE TO ERI AND YNG INTO THE OVERNIGHT HOURS. THE HRRR MODEL INDICATES SOME INCREASE IN LOW CLOUD COVERAGE EAST OF CLE AFTER 00 UTC AND THIS SEEMS REASONABLE. SOME LIGHT LAKE EFFECT SNOW IS POSSIBLE OVER EXTREME NE OHIO AND NW PA. VFR VSBYS SHOULD PREVAIL OUTSIDE THE SNOW SHOWERS. LIGHT WINDS ARE EXPECTED. .OUTLOOK...AREAS OF NON VFR CEILINGS LATE MONDAY NIGHT THROUGH WEDNESDAY ESPECIALLY ACROSS NE OH/NW PA. && .MARINE... ARCTIC HIGH PRESSURE WILL GRADUALLY BUILD SOUTH AND EAST ACROSS THE GREAT LAKES INTO WEDNESDAY. A REINFORCING COLD FRONT WILL MOVE THROUGH THE NORTHERN LAKES WEDNESDAY NIGHT AND THURSDAY WHICH WILL STRENGTHEN THE PRESSURE GRADIENT ACROSS THE EASTERN LAKES AND MAY PRODUCE GALES ON LAKE ERIE LATE WEDNESDAY INTO THURSDAY. WINDS WILL SLACKEN BRIEFLY FRIDAY AS HIGH PRESSURE BUILDS OVER THE SOUTHEAST. MEANWHILE LOW PRESSURE WILL FORM OVER THE GULF COAST AND GRADUALLY HEAD NORTHEAST TO THE MID ATLANTIC COAST BY MONDAY. HIGH PRESSURE WILL BUILD EAST ACROSS ONTARIO JUST TO THE NORTH OF THE GREAT LAKES. THERE IS SOME QUESTION ABOUT THE TRACK OF THIS LOW AND RESULTANT WIND FORECAST FOR LAKE ERIE IS QUESTIONABLE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KUBINA NEAR TERM...KUBINA SHORT TERM...KUBINA LONG TERM...LAPLANTE AVIATION...LAPLANTE MARINE...LAPLANTE
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
111 PM EST SUN DEC 28 2014 .SYNOPSIS... WEAK HIGH PRESSURE WILL BUILD IN TODAY BEHIND A COLD FRONT...NOW EAST OF THE AREA. ANOTHER COLD FRONT WILL DROP ACROSS THE AREA ON MONDAY AND WILL USHER IN NOTICEABLY COLDER AIR FOR MID WEEK. && .NEAR TERM /THROUGH TONIGHT/... THE PRECIP IS PRETTY MUCH GONE AND HAVE GONE AHEAD AND PULLED THE REMAINING PRECIP FROM THE FORECAST. HAVE SLOWED THE CLEARING DOWN A LITTLE. STILL THINK WESTERN AREAS WILL BE PARTLY SUNNY BY MID AFTERNOON. ORIGINAL...COLD FRONT NOW ABOUT TO EXIT THE AREA TO THE EAST. DRIER AIR HAS MOVED IN FROM THE WEST ENDING PRECIP JUST WEST OF A CLE- MNN LINE. CURRENT TIMING OF THE BACK EDGE TAKES IT TO NEAR AN KERI-KCAK LINE ABOUT 1015Z AND SOUTHEAST OF THE AREA BY 13Z OR SO. PRECIP COULD END AS A MIX AS TEMPS DROP TOWARD MORNING BUT NOT LOOKING FOR ANY SIGNIFICANT WINTRY PRECIP. AS FOR CLOUD COVER...SATELLITE SHOWS STRATUS WEST OF CHICAGO ALTHOUGH RANDOM HOLES ARE DEVELOPING FROM TIME TO TIME. BELIEVE DAY WILL BEGIN CLOUDY ALL AREA BUT STILL THINKING THERE WILL BE BREAKS ESPECIALLY NORTHWEST AS WE WILL BE ON THE PERIPHERY OF THE SURFACE HIGH AND LOW LEVEL FLOW WILL TEND TO MIX. HIGHS NOT FAR FROM CURRENT TEMPS MOST PLACES. CURRENTLY CAK AND YNG ARE JUST AHEAD OF THE FRONT WITH TEMPS IN THE MID 40S SO HIGHS THERE ACTUALLY LOWER THAN CURRENT AS TEMPS WILL GET KNOCKED DOWN TO NEAR 40 BEFORE DAYBREAK. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... EXPECTING DRY WX TONIGHT THROUGH MONDAY MID DAY. SLIGHT CHANCES RETURNING FOR THE SNOWBELT AREAS MONDAY AFTERNOON INCREASING TO CHANCE MONDAY NIGHT AS COLDER AIR DEEPENS POST SECONDARY FRONT AS 850MB TEMPS DROP TO -12-14C. STILL WITH LAKE TEMPS AT +3C...DIFFERENTIAL ONLY MARGINALLY FAVORABLE FOR LES. WILL CONTINUE WITH SMALL CHANCE POPS SNOWBELT EARLY TUESDAY AND SLIGHT CHANCE POPS ELSEWHERE AS MOISTURE SPREADS EAST ACROSS THE AREA WITH A WEAK UPPER TROF/SHORT WAVE. HIGH PRESSURE WILL BUILD IN FROM THE WEST TUESDAY AFTERNOON HOWEVER TO DRIED IT OUT FOR THE AFTERNOON. TUESDAY NIGHT AND WEDNESDAY...850MB TEMPS CONTINUE TO DROP THROUGH -15 TO -18C BY WEDNESDAY MORNING WITH AT LEAST LIMITED MOISTURE SO WILL BRING CHANCE POPS FOR LES BACK TO THE LAKESHORE. DRY AIR ELSEWHERE HOWEVER. && .LONG TERM /THURSDAY THROUGH SATURDAY/... ON THURSDAY THE REGION WILL BE ON THE EDGE OF THE COLDER AIR WITH THE NORTHERN STREAM JET POSITIONED FROM SOUTH CENTRAL CANADA...ACROSS THE GREAT LAKES INTO NEW ENGLAND. SURFACE HIGH PRESSURE CENTERED TO OUR SOUTH AND LOW PRESSURE OVER HUDSON BAY WILL PROVIDE FOR A SOUTHWEST FLOW AND NOT ALLOW ANY MORE OF THE COLD AIR TO SINK SOUTHWARD FOR THE TIME BEING. IT WILL ALSO BE DRY. THE FORECAST FOR FRIDAY INTO THE WEEKEND GETS MUCH MORE COMPLICATED WITH THE INTERACTION BETWEEN SHORTWAVE ENERGY EJECTING OUT OF THE FOUR CORNERS REGION AND A DIGGING TROUGH FROM THE NORTHERN ROCKIES AND NORTHERN PLAINS. LOOKING TOWARD THE ENSEMBLES FOR NOW PLACES LOW PRESSURE IN THE GENERAL REGION BETWEEN SATURDAY AND SUNDAY. AS WARM AIR ADVANCES NORTHWARD PRECIPITATION TYPE WILL BE AN ISSUE WITH A WINTRY MIX POSSIBLE AT ONSET AND A PERIOD OF RAIN POSSIBLE TOO. THE DEGREE/SPEED THE COLD AIR MOVES IN ON THE BACKSIDE IS IN QUESTION TOO...AS WOULD BE EXPECTED THIS FAR OUT. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... GRADUAL IMPROVEMENT IN CEILING HEIGHT IS EXPECTED THIS AFTERNOON AND EVENING MAINLY AWAY FROM LAKE ERIE. WIDELY SCATTERED LIGHT RA-/SN- FROM GEAUGA COUNTY TO YNG SHOULD END BY THE MIDDLE OF THE AFTERNOON. EXPECT A SCATTERING OUT OF LOW CLOUDS WEST OF CLE TOWARD SUNSET WITH CEILINGS GENERALLY LIFTING TO THE 2500-3500FT RANGE FROM MFD TO CLE TO ERI AND YNG INTO THE OVERNIGHT HOURS. THE HRRR MODEL INDICATES SOME INCREASE IN LOW CLOUD COVERAGE EAST OF CLE AFTER 00 UTC AND THIS SEEMS REASONABLE. SOME LIGHT LAKE EFFECT SNOW IS POSSIBLE OVER EXTREME NE OHIO AND NW PA. VFR VSBYS SHOULD PREVAIL OUTSIDE THE SNOW SHOWERS. LIGHT WINDS ARE EXPECTED. .OUTLOOK...AREAS OF NON VFR CEILINGS LATE MONDAY NIGHT THROUGH WEDNESDAY ESPECIALLY ACROSS NE OH/NW PA. && .MARINE... WILL CONTINUE WITH THE ONGOING SMALL CRAFT ADVISORY FOR THE EAST TWO THIRDS UNTIL MID MORNING...WITH WINDS/WAVES SUBSIDING AFTER THAT. HIGH PRESSURE BUILDS OVER THE LAKE TODAY IN THE WAKE OF LAST NIGHTS COLD FRONT. HIGH PRESSURE WILL CONTINUE TO BE THE MAIN INFLUENCE ON THE LAKE WEATHER FROM MONDAY THROUGH WEDNESDAY AS IT SHIFTS FROM THE NORTHERN ROCKIES AND PLAINS SOUTH TO THE CENTRAL PLAINS. NORTHWEST WINDS TODAY WILL BECOME MORE NORTHERLY BY TUESDAY MORNING AND THEN THEY WILL SETTLE BACK TOWARDS SOUTHWEST AS THAT HIGH SHIFTS SOUTH. NEXT INCREASE IN WIND/WAVES LOOKS LIKELY FOR WEDNESDAY NIGHT INTO THURSDAY AS THE GRADIENT TIGHTENS BETWEEN THAT HIGH AND LOW PRESSURE OVER HUDSON BAY. THE SOUTHWEST FLOW ON THE LAKE...FOR NOW...WILL BE FORECAST TO 30 KNOTS. THERE IS SOME POTENTIAL FOR GALE FORCE WINDS WITH THE GRADIENT AND FETCH. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK/KUBINA SHORT TERM...TK LONG TERM...OUDEMAN AVIATION...LAPLANTE MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
904 PM CST MON DEC 29 2014 ...UPDATE... .DISCUSSION... RADAR ECHOES ARE LEAVING THE FORECAST AREA...SO WILL DROP MENTION OF FLURRIES FOR THE REMAINDER OF THE OVERNIGHT PERIOD. 00Z NAM...01Z HRRR AND 02Z RAP ALL APPEAR DRY FOR THE REST OF THE NIGHT. LFM IS MISSING...ALONG WITH BAROTROPIC AND SHIP PAPA DATA. ...HAVING A RIP VAN WINKLE MOMENT... WILL UPDATE TO TAKE OUT FLURRIES AND SPRINKLES. APPEARS THE COLD SURGE IS STILL IN KANSAS...FROM JUST SOUTH OF MKC TO NORTH OF ICT TO NEAR AMA...BASED MAINLY ON LOCATION OF STRONGEST WINDS AND GUSTINESS. PROGRESS HAS BEEN SLOW...BUT ON TARGET FOR TUESDAY MORNING. NO CHANGE TO MINIMUM TEMPS. && .PRELIMINARY POINT TEMPS/POPS... TUL 48 28 32 14 / MMM 10 0 10 FSM 45 30 42 22 / MMM 0 0 0 MLC 50 31 38 19 / MMM 0 0 10 BVO 46 24 29 12 / MMM 10 10 10 FYV 45 28 36 14 / MMM 0 0 0 BYV 43 27 36 14 / MMM 0 0 0 MKO 47 28 35 16 / MMM 0 0 10 MIO 45 27 31 12 / MMM 10 10 0 F10 47 29 34 16 / MMM 0 0 10 HHW 48 29 44 24 / MMM 0 0 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...02 LONG TERM....02
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
948 PM EST MON DEC 29 2014 .SYNOPSIS.... A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA WITH A STRONG RIDGE OVER THE NORTHWEST AND A TROUGH OVER THE NORTHEAST WILL PRODUCE TWO COLD SURGES. THE FIRST SHOULD PRODUCE COLD WEATHER TROUGH NEW YEARS. A SOUTHERN STREAM STORM COULD BRING A WINTRY MIX AND/OR RAIN TO THE REGION AHEAD OF THE FORECAST SECOND SURGE OF COLD CONTINENTAL AIR. LONGER RANGE FORECASTS SHOW A LESS AMPLIFIED PATTERN DEVELOPING LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... SATELLITE CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SUGGESTS OUR FORECASTS IN SOUTH/CENTRAL ARE TOO CLOUDY. HRRR ALSO SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT IN NORTHWEST. THE WEAK NORTHWEST FLOW OUT OF THE HIGH DOES NOT CAUSE THE MODEL TO GENERATE ANY LAKE ENHANCED SNOWS. CHILLY NIGHT AND ADJUSTED TEMPERATURES WITH NEWER GUIDANCE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES AND PERHAPS SNOW IN NORTHERN AND SOME CENTRAL AREAS. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
937 PM EST MON DEC 29 2014 .SYNOPSIS... A COLD STRETCH OF WEATHER IS IN STORE FOR CENTRAL PA WITH TEMPERATURES BELOW SEASONAL NORMALS FOR THE REST OF THE WEEK. WEAK DISTURBANCES WILL BRING FLURRIES OVER THE WEST AND NORTH AT TIMES. THE NEXT CHANCE FOR MEANINGFUL PRECIPITATION WILL NOT BE UNTIL THE WEEKEND. && .NEAR TERM /UNTIL 7 AM TUESDAY MORNING/... SATELLITE CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SUGGESTS OUR FORECASTS IN SOUTH/CENTRAL ARE TOO CLOUDY. HRRR ALSO SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT IN NORTHWEST. THE WEAK NORTHWEST FLOW OUT OF THE HIGH DOES NOT CAUSE THE MODEL TO GENERATE ANY LAKE ENHANCED SNOWS. CHILLY NIGHT AND ADJUSTED TEMPERATURES WITH NEWER GUIDANCE. && .SHORT TERM /7 AM TUESDAY MORNING THROUGH WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
904 PM EST MON DEC 29 2014 .SYNOPSIS... A COLD STRETCH OF WEATHER IS IN STORE FOR CENTRAL PA WITH TEMPERATURES BELOW SEASONAL NORMALS FOR THE REST OF THE WEEK. WEAK DISTURBANCES WILL BRING FLURRIES OVER THE WEST AND NORTH AT TIMES. THE NEXT CHANCE FOR MEANINGFUL PRECIPITATION WILL NOT BE UNTIL THE WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ADJUSTED THE FORECAST WITH NEWER GUIDANCE. ALL CHANGES MINOR. SATELLITE SHOWS LOWER CLOUDS TO THE NORTH AND CIRRUS TO OUR SOUTH. THE LARGER SCALE GUIDANCE SHOWS THE IMPLIED CLOUDS OVER THE ENTIRE REGION WHILE THE HRRR SHOWS THE RELATIVE CLEAR SLOT OVER PORTIONS OF CENTRAL PA WHICH IS IN THE 11-3.9 MICRON DATA. THE CLOUDS IN THE NORTH GET REINFORCED OVERNIGHT AND THE CLEAR TO PARTLY CLEAR AREA IN THE HRRR DRIFTS TO THE SOUTH AND EAST. PORTIONS OF CENTRAL AND SOUTHEASTERN SHOULD BE PARTLY CLEAR AT TIMES. THE HRRR ALSO SHOWS...LIKE A FEW OTHER MODELS SOME VERY LIGHT SNOW SHOWERS OR FLURRIES IN THE NORTHWEST OVERNIGHT. NOTHING OF NOTE. MOSTLY NORTH-NORTHWEST FLOW ON COLD SIDE OF THE BIG ANTICYCLONE TO OUR WEST. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... MINOR TWEAKS TO FORECAST WITH LATEST GUIDANCE. MODELS BEGIN TO SHOW THE IMPACT OF THE CONTINUED NORTHERLY FLOW WITH CHANCE AND SLIGHT CHANCE POPS OVER THE NORTHWEST. THE FLOW IS ON THE COLD SIDE OF A MASSIVE SURFACE ANTICYCLONE TO OUR WEST. AS PER THE SNOW SHOWERS...INITIALLY SREF AND EC-EFS SHOW THE LES MAINLY IN NY BUT OVERTIME MAINLY LATE TUESDAY INTO WEDNESDAY...THEY SHOW THE EVOLUTION OF BETTER LAKE ERIE SNOW SHOWER POTENTIAL INTO NW PA. EDGED UP POPS TUESDAY INTO WEDNESDAY AS THE -18C AIR AT 850 MB SETTLE OVER NORTHERN AREAS OF THE STATE. CLEARLY...WE ARE GOING TO SEE IT GET INCREMENTALLY COLDER OVER THE NEXT FEW DAYS BOTTOMING OUT AROUND NEW YEARS DAY (SEE BELOW)...AS NOTED IN PREVIOUS DISCUSSION: MAX TEMPS TUES AND WED WILL BE 5-10F BELOW NORMALS. THIS IS NOTEWORTHY BECAUSE WE HAVE ONLY HAD ONE OR TWO DAYS BELOW NORMAL SINCE THE LIGHT SNOW THAT FELL ON THE 10TH/11TH. AVERAGE TEMPS FOR THE LAST 6 DAYS HAVE BEEN 10-20F ABOVE NORMAL EACH DAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...GRUMM SHORT TERM...GRUMM/DANGELO LONG TERM...RXR AVIATION...DANGELO/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
712 PM EST MON DEC 29 2014 .SYNOPSIS... A COLD STRETCH OF WEATHER IS IN STORE FOR CENTRAL PA WITH TEMPERATURES BELOW SEASONAL NORMALS FOR THE REST OF THE WEEK. WEAK DISTURBANCES WILL BRING FLURRIES OVER THE WEST AND NORTH AT TIMES. THE NEXT CHANCE FOR MEANINGFUL PRECIPITATION WILL NOT BE UNTIL THE WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ADJUSTED THE FORECAST WITH NEWER GUIDANCE. ALL CHANGES MINOR. SATELLITE SHOWS LOWER CLOUDS TO THE NORTH AND CIRRUS TO OUR SOUTH. THE LARGER SCALE GUIDANCE SHOWS THE IMPLIED CLOUDS OVER THE ENTIRE REGION WHILE THE HRRR SHOWS THE RELATIVE CLEAR SLOT OVER PORTIONS OF CENTRAL PA WHICH IS IN THE 11-3.9 MICRON DATA. THE CLOUDS IN THE NORTH GET REINFORCED OVERNIGHT AND THE CLEAR TO PARTLY CLEAR AREA IN THE HRRR DRIFTS TO THE SOUTH AND EAST. PORTIONS OF CENTRAL AND SOUTHEASTERN SHOULD BE PARTLY CLEAR AT TIMES. THE HRRR ALSO SHOWS...LIKE A FEW OTHER MODELS SOME VERY LIGHT SNOW SHOWERS OR FLURRIES IN THE NORTHWEST OVERNIGHT. NOTHING OF NOTE. MOSTLY NORTH-NORTHWEST FLOW ON COLD SIDE OF THE BIG ANTICYCLONE TO OUR WEST. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/... MINOR TWEAKS TO FORECAST WITH LATEST GUIDANCE. MODELS BEGIN TO SHOW THE IMPACT OF THE CONTINUED NORTHERLY FLOW WITH CHANCE AND SLIGHT CHANCE POPS OVER THE NORTHWEST. THE FLOW IS ON THE COLD SIDE OF A MASSIVE SURFACE ANTICYCLONE TO OUR WEST. AS PER THE SNOW SHOWERS...INITIALLY SREF AND EC-EFS SHOW THE LES MAINLY IN NY BUT OVERTIME MAINLY LATE TUESDAY INTO WEDNESDAY...THEY SHOW THE EVOLUTION OF BETTER LAKE ERIE SNOW SHOWER POTENTIAL INTO NW PA. EDGED UP POPS TUESDAY INTO WEDNESDAY AS THE -18C AIR AT 850 MB SETTLE OVER NORTHERN AREAS OF THE STATE. CLEARLY...WE ARE GOING TO SEE IT GET INCREMENTALLY COLDER OVER THE NEXT FEW DAYS BOTTOMING OUT AROUND NEW YEARS DAY (SEE BELOW)...AS NOTED IN PREVIOUS DISCUSSION: MAX TEMPS TUES AND WED WILL BE 5-10F BELOW NORMALS. THIS IS NOTEWORTHY BECAUSE WE HAVE ONLY HAD ONE OR TWO DAYS BELOW NORMAL SINCE THE LIGHT SNOW THAT FELL ON THE 10TH/11TH. AVERAGE TEMPS FOR THE LAST 6 DAYS HAVE BEEN 10-20F ABOVE NORMAL EACH DAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS THIS AFTN/EVENING. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...GRUMM SHORT TERM...GRUMM/DANGELO LONG TERM...RXR AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
701 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL BRING RAIN SHOWERS TONIGHT AND SUNDAY. THE SHOWERS WILL BECOME MIXED WITH A LITTLE SNOW ACROSS THE WESTERN MOUNTAINS THE MORNING. COLDER AND DRIER AIR WILL CONTINUE TO FILTER INTO THE AREA FOR THE NEXT SEVERAL DAYS WITH TEMPERATURES RETURNING BACK TO SEASONAL NORMALS...WHICH WILL FEEL QUITE COLD CONSIDERING HOW WARM IT HAS BEEN RECENTLY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TRACKING SEVERAL BANDS OF FAST MOVING SHOWER ACTIVITY MAINLY ACROSS W AND N CWA AT 0830Z. IN GENERAL THE SHOWERS HAVE WEAKENED AS THEY ADVANCE EAST. MOST ORGANIZED AREA OF SHOWERS ENTERING WEST COUNTIES RIGHT NOW. HRRR WEAKENS THIS BAND AS IT MOVES DEEPER INTO THE CWA...THOUGH EXPECT MOST OF THE AREA TO PICK UP SOME MEASURABLE RAINFALL THIS MORNING. COLDER AIR ALSO ACCOMPANYING THESE SHOWERS AND MOST OF THE AREA WILL SEE FALLING OR STEADY TEMPERATURES TODAY. SHOWERS WILL MIX AND CHANGE OVER TO SNOW ACROSS WESTERN MOUNTAINS WITH ONLY LIGHT ACCUMULATIONS EXPECTED. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... FRONTAL BAND SLOW SHIFTS SOUTH OF CWA THIS EVENING WITH ORGANIZED SHOWERS WANING. SHOWERS ACROSS PA/MD BORDER MAY HAVE ENOUGH COLD AIR MAY ARRIVE TO RESULT IN SNOW BUT QPF WILL BE VERY LIGHT AND NO ACCUMULATIONS ARE EXPECTED. QUIET WEATHER ON MONDAY WITH TEMPERATURES COOLER THEN PAST SEVERAL DAYS BUT STILL ABOVE AVERAGE FOR LATE DEC. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS MENTIONED IN PREVIOUS DISCUSSIONS...A WAVE DEVELOPS SOUTH OF THE AREA AND TRACKS NORTHEAST. MORE CONFIDENCE THAT IMPACTS FROM THIS SYSTEM WILL STAY WELL SOUTH AND EAST OF THE CWA MON NIGHT AND TUE. HIGH PRESSURE WILL BUILD OVER THE MIDDLE OF THE COUNTY BY MIDWEEK AND SLOWLY DRIFT OFF THE EAST COAST BY THE END OF THE WORKWEEK...BRINGING AN EXTENDED PERIOD OF FAIR WEATHER TO THE FORECAST AREA. HOWEVER...WAVES OF COLDER AIR DIVING DOWN FROM THE NORTH WILL HELP TEMPERATURES WILL RETURN TO NORMAL FOR THE LAST WEEK OF DECEMBER. COOLER AIR AND BREEZY CONDITIONS WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND LONG RANGE GUIDANCE SHOWS THE FIRST SIGNIFICANT STORM OF 2015 DEVELOPS NEXT WEEKEND. STORM TRACK WILL BE CRITICAL AS TO WHAT TYPE OF PRECIPITATION FALLS ACROSS THE AREA. RIGHT NOW IT LOOKS LIKE THE SURFACE LOW WILL TRACK WEST OF PA BRINGING ANOTHER SHOT OF MILD AIR BACK INTO THE STATE WITH RAIN THE LIKELY DOMINANT PRECIPITATION TYPE. HOWEVER THERE IS STILL MUCH UNCERTAINTY GIVEN THAT THIS SYSTEM IS ALMOST A WEEK OUT. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... THE STRONG BAND THAT WAS ALONG THE COLD FRONT HAS DISSIPATED AS IT MOVED EASTWARD. REDUCING CONDITIONS REMAIN THROUGH THE WESTERN TAF SITES DUE TO THE UPSLOPE FLOW AND SHOWERS FROM THE RESIDUAL MOISTURE. EXPECT IFR AND LOWER AT BFD AND JST THROUGH MID MORNING. AS PRECIP FADES CIGS AND VSBYS WILL IMPROVE...THOUGH REDUCINGCIGS OF MVFR AND LOWER SHOULD REMAIN THROUGH THE EARLY AFTERNOON HOURS. LIGHT SHOWERS REMAIN POSSIBLE THROUGH THE LOWER SUSQ TAF SITES...THOUGH MVFR SHOULD BE THE MAIN CONCERN WITH IMPROVING CONDITIONS BY LATE MORNING. VFR SHOULD RETURN LATE TODAY AS CLEARING SPREADS TO THE SOUTH AS THE FRONT PRESSES SLOWLY SOUTH THRU THE MID- ATLANTIC - EVENTUALLY STALLING OUT THERE. MVFR COULD RETURN TO JST TONIGHT INTO MONDAY MORNING. OUTLOOK... MON-THU...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ROSS NEAR TERM...ROSS SHORT TERM...ROSS LONG TERM...ROSS/HAGNER AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
348 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL BRING RAIN SHOWERS TONIGHT AND SUNDAY. THE SHOWERS WILL BECOME MIXED WITH A LITTLE SNOW ACROSS THE WESTERN MOUNTAINS THE MORNING. COLDER AND DRIER AIR WILL CONTINUE TO FILTER INTO THE AREA FOR THE NEXT SEVERAL DAYS WITH TEMPERATURES RETURNING BACK TO SEASONAL NORMALS...WHICH WILL FEEL QUITE COLD CONSIDERING HOW WARM IT HAS BEEN RECENTLY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TRACKING SEVERAL BANDS OF FAST MOVING SHOWER ACTIVITY MAINLY ACROSS W AND N CWA AT 0830Z. IN GENERAL THE SHOWERS HAVE WEAKENED AS THEY ADVANCE EAST. MOST ORGANIZED AREA OF SHOWERS ENTERING WEST COUNTIES RIGHT NOW. HRRR WEAKENS THIS BAND AS IT MOVES DEEPER INTO THE CWA...THOUGH EXPECT MOST OF THE AREA TO PICK UP SOME MEASURABLE RAINFALL THIS MORNING. COLDER AIR ALSO ACCOMPANYING THESE SHOWERS AND MOST OF THE AREA WILL SEE FALLING OR STEADY TEMPERATURES TODAY. SHOWERS WILL MIX AND CHANGE OVER TO SNOW ACROSS WESTERN MOUNTAINS WITH ONLY LIGHT ACCUMULATIONS EXPECTED. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... FRONTAL BAND SLOW SHIFTS SOUTH OF CWA THIS EVENING WITH ORGANIZED SHOWERS WANING. SHOWERS ACROSS PA/MD BORDER MAY HAVE ENOUGH COLD AIR MAY ARRIVE TO RESULT IN SNOW BUT QPF WILL BE VERY LIGHT AND NO ACCUMULATIONS ARE EXPECTED. QUIET WEATHER ON MONDAY WITH TEMPERATURES COOLER THEN PAST SEVERAL DAYS BUT STILL ABOVE AVERAGE FOR LATE DEC. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS MENTIONED IN PREVIOUS DISCUSSIONS...A WAVE DEVELOPS SOUTH OF THE AREA AND TRACKS NORTHEAST. MORE CONFIDENCE THAT IMPACTS FROM THIS SYSTEM WILL STAY WELL SOUTH AND EAST OF THE CWA MON NIGHT AND TUE. HIGH PRESSURE WILL BUILD OVER THE MIDDLE OF THE COUNTY BY MIDWEEK AND SLOWLY DRIFT OFF THE EAST COAST BY THE END OF THE WORKWEEK...BRINGING AN EXTENDED PERIOD OF FAIR WEATHER TO THE FORECAST AREA. HOWEVER...WAVES OF COLDER AIR DIVING DOWN FROM THE NORTH WILL HELP TEMPERATURES WILL RETURN TO NORMAL FOR THE LAST WEEK OF DECEMBER. COOLER AIR AND BREEZY CONDITIONS WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND LONG RANGE GUIDANCE SHOWS THE FIRST SIGNIFICANT STORM OF 2015 DEVELOPS NEXT WEEKEND. STORM TRACK WILL BE CRITICAL AS TO WHAT TYPE OF PRECIPITATION FALLS ACROSS THE AREA. RIGHT NOW IT LOOKS LIKE THE SURFACE LOW WILL TRACK WEST OF PA BRINGING ANOTHER SHOT OF MILD AIR BACK INTO THE STATE WITH RAIN THE LIKELY DOMINANT PRECIPITATION TYPE. HOWEVER THERE IS STILL MUCH UNCERTAINTY GIVEN THAT THIS SYSTEM IS ALMOST A WEEK OUT. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... COLD FRONT MOVING THROUGH THE STATE OVERNIGHT. SFC MOISTURE CONTINUES TO INCREASE AS LIGHT PRECIP MOVES THROUGH THE NORTHERN HALF OF THE STATE. VFR SHOULD CONTINUE THROUGH THE SOUTHERN TAF SITES OVER THE NEXT FEW HOURS. RAIN SHOWERS ALONG AND AHEAD OF THE FRONT HAVE BROUGHT A LOWERING OF VISBYS AND CIGS TO BFD CURRENTLY...AND IFR CIGS/VIS ARE EXPECTED TO DEVELOP IN THE WESTERN MOUNTAINS OVERNIGHT TO PERHAPS AOO/UNV/IPT AND JST. BFD WILL LIKELY BEGIN TO SEE SNOW MIX IN OR A CHANGE TO ALL SNOW AND THEREFORE THE ATTENDANT LOWER VISBYS AROUND SUNRISE/12Z. JST MAY LOWER TO LIFR AS WELL...MAINLY DUE TO THE PERSISTENT UPSLOPE...BUT ALSO IF THE PRECIP TURNS TO SNOW THERE IN THE MORNING. COLD FRONT SHOULD BE THRU HALF OF THE REGION BY 12Z...BUT IT WILL TAKE THE REST OF THE DAYLIGHT FOR IT TO CLEAR THE SE. LOWER CLOUDS WILL HANG ON THROUGH THE AFTN...BUT VFR MAY RETURN BY 00Z/29TH - IN THE NORTH FIRST THEN CLEARING SPREADS TO THE SOUTH AS THE FRONT PRESSES SLOWLY SOUTH THRU THE MID-ATLANTIC - EVENTUALLY STALLING OUT THERE. OUTLOOK... MON-THU...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ROSS NEAR TERM...ROSS SHORT TERM...ROSS LONG TERM...ROSS/HAGNER AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
123 PM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL SLOWLY CROSS OUR REGION THROUGH MONDAY...THOUGH SOME MOISTURE WILL LINGER UNTIL TUESDAY. DRIER AND COOLER HIGH PRESSURE WILL MOVE ACROSS THE AREA WEDNESDAY AND THURSDAY. ANOTHER LOW PRESSURE SYSTEM THEN SHOULD BEGIN TO TAKE SHAPE AT THE END OF THE WEEK...BRINGING PRECIPITATION BACK TO THE AREA BY FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... 1045 AM EST UPDATE...A BAND OF LIGHT TO MODERATE RAIN CURRENTLY OVER THE SOUTHERN TIER OF THE CWA IS EXPECTED TO EXIT EAST OF THE AREA BY NOON...WITH A DRY SLOT MOVING IN THRU THE REST OF THE REGION THRU THIS AFTERNOON. HENCE...POPS WERE LOWERED INTO THE SLIGHT CHANCE RANGE OVER THE PIEDMONT...AND LOW END CHANCE RANGE IN THE MTNS ZONES BETWEEN 18Z AND 00Z SUN...BEFORE RAMPING BACK UP FROM NW TO SE THRU TONIGHT AS ANOTHER BAND OF PRECIP ASSOCIATED WITH AN UPPER TROUGH AXIS APPROACHES FROM THE WEST. 910 AM EST UPDATE...HAVE RAISED POPS TO 90/100 RANGE THIS MORNING OVER THE SOUTHERN HALF OF THE CWA PER LATEST RADAR TREND. THIS IS WELL IN LINE WITH THE LATEST HRRR WHERE THE HEAVIEST RAIN BAND WILL MOVE ACROSS ALONG AND SOUTHEAST OF THE I-85 THIS MORNING THRU MIDDAY. ALSO...HAVE INCLUDED AREAS OF PATCHY FOG TO ACCOUNT FOR THE LATEST SURFACE OBS. AS OF 645 AM...RAIN SHIELD HAS MADE VERY LITTLE NORTHWARD PROGRESS ABOVE (ROUGHLY) I-85 THIS MORNING...AND AM BEGINNING TO WONDER IF THE PRECIP ISN/T GOING TO JUST FIZZLE MORE OR LESS IN PLACE...AS UPGLIDE WEAKENS...AND THE MID-LEVELS DRY OUT. WILL CONTINUE TO FEATURE HIGH POPS (60-80) ACROSS OUR NC ZONES...BUT THESE HAVE BEEN SCALED BACK FROM THE EARLIER FORECAST. OTHERWISE...TEMPS ARE EXPECTED TO REMAIN MORE OR LESS STEADY THIS MORNING UNDER DENSE CLOUD COVER. AREA OF MODERATE RAIN IS FINALLY PUSHING ACROSS THE UPPER SAVANNAH RIVER VALLEY THIS MORNING. IN GENERAL...THIS IS FARTHER SOUTH THAN WHAT THE MODELS HAVE RECENTLY BEEN DEPICTING...AND THE HIGHEST QPF FOR THIS MORNING HAS BEEN ADJUSTED TO THE UPSTATE AND NORTHEAST GA...WHERE RAINFALL AMOUNTS THIS MORNING SHOULD RANGE FROM ONE QUARTER TO ONE HALF INCH...WITH LOCALLY HIGHER AMOUNTS. THE PRECIP SHIELD IS EXPECTED TO SHIFT NORTHWARD WITH TIME...AS THE BROAD BAND OF ISENTROPIC LIFT TRANSLATES NORTHEAST TOWARD THE MID-ATLANTIC. THEREFORE...THE MOUNTAINS AND FOOTHILLS OF WESTERN NC MAY YET SEE UP TO A HALF INCH OF RAINFALL THIS MORNING...WITH LIGHTER AMOUNTS TOWARD THE I-77 CORRIDOR. AS UPGLIDE SHUTS OFF AND MID-LEVELS DRY OUT THIS AFTERNOON...PRECIP SHOULD COME TO AN END...ALTHOUGH THE LOW LEVELS WILL REMAIN VERY MOIST AND THERE MAY BE PATCHES OF DRIZZLE OR LIGHT RAIN LINGERING. POPS WILL THEREFORE BE KEPT IN THE TOKEN CHANCE RANGE IN MOST AREAS THROUGH THE AFTERNOON. WITH PRECIP FALLING INTO A DRY AIR MASS THIS MORNING...FOLLOWED BY ABUNDANT LOW CLOUD COVER THROUGH THE AFTERNOON...A WEAK IN-SITU CAD EVENT MAY RESULT...AND MAX TEMPS ARE EXPECTED TO END UP BEING RATHER CLOSE TO CLIMO...DESPITE HIGH THICKNESS VALUES FOR THE TIME OF YEAR. A SHORT WAVE TROUGH EJECTING FROM TEXAS/THE LOWER MISS VALLEY TONIGHT WILL DAMPEN AS IT ENCOUNTERS THE CONFLUENT UPPER FLOW ACROSS THE EASTERN CONUS. NEVERTHELESS...A CONSENSUS OF MODEL GUIDANCE DEPICTS WEAK CYCLOGENESIS OCCURRING ALONG A BAROCLINIC ZONE ACROSS GEORGIA AND THE CAROLINAS...SUPPORTING ANOTHER ROUND OF RAINFALL LATE TONIGHT INTO EARLY MONDAY...AND WARRANTING CATEGORICAL POPS IN ALL AREAS ONCE AGAIN. ANOTHER ROUND OF .25-.50 INCH QPF APPEARS LIKELY IN MOST AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 AM SUNDAY...PESKY FRONTAL ZONE FINALLY DOES LOOK TO BE FORCED SOUTH AND EAST OF THE CWFA MONDAY AS A CANADIAN AIRMASS EXPANDS OVER MOST OF THE ERN CONUS. COOLER AND DRIER AIR DO START TO FILTER IN BY MONDAY NIGHT...BUT SOME LLVL MOISTURE DOES LINGER INTO TUE. THE SOUTHEAST REMAINS UNDER BROADLY CYCLONIC FLOW THROUGH THAT TIME...WITH AN EMBEDDED SHORTWAVE PROGGED TO MOVE FROM THE MID MISSISSIPPI VALLEY TO THE DELMARVA BY TUE NIGHT. A WEAK BOUNDARY ASSOCIATED WITH THIS WAVE WILL ENHANCE COLD ADVECTION AND LLVL LIFT MON NIGHT/EARLY TUE...IN TIME TO ENCOUNTER THE MOISTURE. THUS POPS EXHIBIT A SECONDARY PEAK TUE MRNG. AS WINDS VEER TO NW AROUND THAT TIME...SOME UPSLOPE ENHANCEMENT IS ALSO EXPECTED WITH POPS TAKING A LITTLE LONGER TO TAPER OFF TUE NEAR THE TENN BORDER. TEMPS ARE EXPECTED TO REMAIN ABOVE CLIMO THROUGH TUE MRNG. PROFILES INDICATE AN ACCORDINGLY WARM COLUMN...AND THE MOISTURE WILL BE CONCENTRATED IN THE LOW TO MID LEVELS. ICE NUCLEATION AND SNOW PRODUCTION ARE UNLIKELY...SO WITH TEMPS REMAINING ABOVE FREEZING THROUGHOUT THE CWFA MON NIGHT NO MENTION OF WINTRY PRECIP HAS BEEN MADE. IN THE WAKE OF THE BOUNDARY DEEPER DRYING BEGINS LATER TUE AND CONTINUES THROUGH MID-WEEK...WITH SKIES TRENDING CLEARER. MAX TEMPS WILL RETURN TO AROUND CLIMO TUE FOLLOWED BY SIMILARLY NORMAL TEMPS FOR WED MRNG. DESPITE THE COLD ADVECTION...NOTABLY GUSTY WINDS ARE NOT EXPECTED WITH THE LEADING EDGE OF THE AIRMASS HAVING ALREADY PUSHED THROUGH. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 245 AM SUNDAY...REMARKABLY STRONG SFC HIGH PRESSURE OVER THE CENTRAL PLAINS GETS SHUNTED SWD AS NRN STREAM SHORTWAVE DIVES INTO THE MIDWEST AND PATTERN BEGINS TO REAMPLIFY OVER THE EAST. DRY AND SEASONABLY COOL WEATHER WILL CONTINUE FOR OUR AREA WED-THU WITH TEMPS NEAR CLIMO. THE SFC HIGH MOVES OVER THE SOUTHEAST BY THU NIGHT INITIATING RETURN FLOW INTO THE WRN GULF STATES AS THE CUTOFF LOW OVER THE DESERT SOUTHWEST PICKS UP SPEED. EVENTUALLY THAT WILL TRACK ACRS THE MIDDLE OR LOWER MISSISSIPPI VALLEY...SPINNING UP A NEW SYSTEM. AGREEMENT BETWEEN THE 28/00Z RUNS OF THE GFS AND EC IS GENERALLY GOOD...NOW ONLY SHOWING MINOR DIFFERENCES IN THE SFC LOW TRACK. REGARDLESS OF THE PRECISE TRACK PRECIP CHANCES BEGIN TO INCREASE THU NIGHT BEFORE PEAKING SATURDAY. MODELS HINT AT SOME PTYPE CONCERNS EARLY IN THE EVENT WITH A POSSIBLE IN-SITU CAD EVENT DEVELOPING...BUT THE BULK OF THE PRECIP SHOULD BE RAIN WITH TEMPS TRENDING ABOVE NORMAL BEYOND FRIDAY. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... AT KCLT...A BRIEF PERIOD OF VFR/MVFR CIGS EARLY THIS AFTERNOON IN RESPONSE TO INCREASING SW WINDS AHEAD OF AN APPROACHING SURFACE COLD FRONT WILL QUICKLY GIVE WAY TO IFR CIGS...AS LATEST VISBY SATELLITE SHOWS CONSIDERABLE IFR CLOUDS SPREADING BACK IN FROM THE SW. LATEST GUIDANCE IS SUPPORTIVE OF LIFR CIGS THIS EVENING THRU THE END OF THE TAF PERIOD. HENCE...HAVE MENTIONED 200-400FT RANGE CIGS BEYOND 22Z...CONTINUING THRU 18Z MON. SW WINDS WILL VEER TO THE NORTH AS THE FRONT PUSHES THRU TONIGHT. AS A WAVE OF SURFACE LOW SETS UP OVER THE WESTERN CAROLINAS...PRECIP WILL SPREAD OVER THE REGION AND WINDS WILL VEER MORE TO THE NE BY MON MORNING. AREAS OF FOG WITH IFR VISBY WILL AFFECT THE TERMINAL TONIGHT AND TOMORROW AS LLVL COOL AND MOIST AIRMASS SPREADS FROM THE NE UNDERNEATH THE PERSISTING WAA SWLY FLOW ALOFT. ELSEWHERE...BKN TO SCT VISBY/MVFR CLOUDS CURRENTLY OVER THE NC MTNS AND PORTIONS OF THE WESTERN NC PIEDMONT WILL GIVE WAY TO OVC IFR CLOUDS BY LATE THIS AFTERNOON/EVENING AS A BAND OF PRECIP ASSOCIATED WITH AN UPPER TROUGH AXIS PUSHES THRU THE AREA. ELSEWHERE WILL SEE CONTINUED IFR CONDITIONS THRU THE PERIOD. AREAS OF FOG WITH IFR VISBY WILL DEVELOP ACROSS MUCH OF THE REGION TONIGHT...MOIST AND COOLER AIRMASS SPREADS IN FROM THE NE BEHIND THE DEPARTING COLD FRONT. WITH A WAVE OF SURFACE LOW SETS UP ACROSS THE WESTERN CAROLINAS BY EARLY MON...LIFR CLOUDS AND AREAS OF PRECIP WILL AFFECT THE MOST LOCATIONS IN ITS WAKE. S/SW WINDS WILL VEER TO THE N TONIGHT WITH THE FROPA...AND VEER TO THE NE BY MON MORNING. OUTLOOK...PERIODS OF LIGHT RAIN AND FLIGHT RESTRICTIONS MAY LINGER MONDAY AND MONDAY NIGHT BEFORE GRADUAL IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD RETURN BY MID-WEEK. CONFIDENCE TABLE... 18-24Z 00-06Z 06-12Z 12-18Z KCLT MED 65% MED 66% MED 68% MED 68% KGSP MED 76% MED 66% MED 61% MED 65% KAVL MED 68% MED 62% MED 67% MED 76% KHKY MED 62% LOW 55% MED 64% MED 76% KGMU MED 72% MED 66% MED 64% MED 62% KAND MED 72% MED 66% MED 67% MED 68% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...JDL/JOH SHORT TERM...WIMBERLEY LONG TERM...ARK/WIMBERLEY AVIATION...JOH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1043 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL SLOWLY CROSS OUR REGION THROUGH MONDAY...THOUGH SOME MOISTURE WILL LINGER UNTIL TUESDAY. DRIER AND COOLER HIGH PRESSURE WILL MOVE ACROSS THE AREA WEDNESDAY AND THURSDAY. ANOTHER LOW PRESSURE SYSTEM THEN SHOULD BEGIN TO TAKE SHAPE AT THE END OF THE WEEK...BRINGING PRECIPITATION BACK TO THE AREA BY FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... 1045 AM EST UPDATE...A BAND OF LIGHT TO MODERATE RAIN CURRENTLY OVER THE SOUTHERN TIER OF THE CWA IS EXPECTED TO EXIT EAST OF THE AREA BY NOON...WITH A DRY SLOT MOVING IN THRU THE REST OF THE REGION THRU THIS AFTERNOON. HENCE...POPS WERE LOWERED INTO THE SLIGHT CHANCE RANGE OVER THE PIEDMONT...AND LOW END CHANCE RANGE IN THE MTNS ZONES BETWEEN 18Z AND 00Z SUN...BEFORE RAMPING BACK UP FROM NW TO SE THRU TONIGHT AS ANOTHER BAND OF PRECIP ASSOCIATED WITH AN UPPER TROUGH AXIS APPROACHES FROM THE WEST. 910 AM EST UPDATE...HAVE RAISED POPS TO 90/100 RANGE THIS MORNING OVER THE SOUTHERN HALF OF THE CWA PER LATEST RADAR TREND. THIS IS WELL IN LINE WITH THE LATEST HRRR WHERE THE HEAVIEST RAIN BAND WILL MOVE ACROSS ALONG AND SOUTHEAST OF THE I-85 THIS MORNING THRU MIDDAY. ALSO...HAVE INCLUDED AREAS OF PATCHY FOG TO ACCOUNT FOR THE LATEST SURFACE OBS. AS OF 645 AM...RAIN SHIELD HAS MADE VERY LITTLE NORTHWARD PROGRESS ABOVE (ROUGHLY) I-85 THIS MORNING...AND AM BEGINNING TO WONDER IF THE PRECIP ISN/T GOING TO JUST FIZZLE MORE OR LESS IN PLACE...AS UPGLIDE WEAKENS...AND THE MID-LEVELS DRY OUT. WILL CONTINUE TO FEATURE HIGH POPS (60-80) ACROSS OUR NC ZONES...BUT THESE HAVE BEEN SCALED BACK FROM THE EARLIER FORECAST. OTHERWISE...TEMPS ARE EXPECTED TO REMAIN MORE OR LESS STEADY THIS MORNING UNDER DENSE CLOUD COVER. AREA OF MODERATE RAIN IS FINALLY PUSHING ACROSS THE UPPER SAVANNAH RIVER VALLEY THIS MORNING. IN GENERAL...THIS IS FARTHER SOUTH THAN WHAT THE MODELS HAVE RECENTLY BEEN DEPICTING...AND THE HIGHEST QPF FOR THIS MORNING HAS BEEN ADJUSTED TO THE UPSTATE AND NORTHEAST GA...WHERE RAINFALL AMOUNTS THIS MORNING SHOULD RANGE FROM ONE QUARTER TO ONE HALF INCH...WITH LOCALLY HIGHER AMOUNTS. THE PRECIP SHIELD IS EXPECTED TO SHIFT NORTHWARD WITH TIME...AS THE BROAD BAND OF ISENTROPIC LIFT TRANSLATES NORTHEAST TOWARD THE MID-ATLANTIC. THEREFORE...THE MOUNTAINS AND FOOTHILLS OF WESTERN NC MAY YET SEE UP TO A HALF INCH OF RAINFALL THIS MORNING...WITH LIGHTER AMOUNTS TOWARD THE I-77 CORRIDOR. AS UPGLIDE SHUTS OFF AND MID-LEVELS DRY OUT THIS AFTERNOON...PRECIP SHOULD COME TO AN END...ALTHOUGH THE LOW LEVELS WILL REMAIN VERY MOIST AND THERE MAY BE PATCHES OF DRIZZLE OR LIGHT RAIN LINGERING. POPS WILL THEREFORE BE KEPT IN THE TOKEN CHANCE RANGE IN MOST AREAS THROUGH THE AFTERNOON. WITH PRECIP FALLING INTO A DRY AIR MASS THIS MORNING...FOLLOWED BY ABUNDANT LOW CLOUD COVER THROUGH THE AFTERNOON...A WEAK IN-SITU CAD EVENT MAY RESULT...AND MAX TEMPS ARE EXPECTED TO END UP BEING RATHER CLOSE TO CLIMO...DESPITE HIGH THICKNESS VALUES FOR THE TIME OF YEAR. A SHORT WAVE TROUGH EJECTING FROM TEXAS/THE LOWER MISS VALLEY TONIGHT WILL DAMPEN AS IT ENCOUNTERS THE CONFLUENT UPPER FLOW ACROSS THE EASTERN CONUS. NEVERTHELESS...A CONSENSUS OF MODEL GUIDANCE DEPICTS WEAK CYCLOGENESIS OCCURRING ALONG A BAROCLINIC ZONE ACROSS GEORGIA AND THE CAROLINAS...SUPPORTING ANOTHER ROUND OF RAINFALL LATE TONIGHT INTO EARLY MONDAY...AND WARRANTING CATEGORICAL POPS IN ALL AREAS ONCE AGAIN. ANOTHER ROUND OF .25-.50 INCH QPF APPEARS LIKELY IN MOST AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 AM SUNDAY...PESKY FRONTAL ZONE FINALLY DOES LOOK TO BE FORCED SOUTH AND EAST OF THE CWFA MONDAY AS A CANADIAN AIRMASS EXPANDS OVER MOST OF THE ERN CONUS. COOLER AND DRIER AIR DO START TO FILTER IN BY MONDAY NIGHT...BUT SOME LLVL MOISTURE DOES LINGER INTO TUE. THE SOUTHEAST REMAINS UNDER BROADLY CYCLONIC FLOW THROUGH THAT TIME...WITH AN EMBEDDED SHORTWAVE PROGGED TO MOVE FROM THE MID MISSISSIPPI VALLEY TO THE DELMARVA BY TUE NIGHT. A WEAK BOUNDARY ASSOCIATED WITH THIS WAVE WILL ENHANCE COLD ADVECTION AND LLVL LIFT MON NIGHT/EARLY TUE...IN TIME TO ENCOUNTER THE MOISTURE. THUS POPS EXHIBIT A SECONDARY PEAK TUE MRNG. AS WINDS VEER TO NW AROUND THAT TIME...SOME UPSLOPE ENHANCEMENT IS ALSO EXPECTED WITH POPS TAKING A LITTLE LONGER TO TAPER OFF TUE NEAR THE TENN BORDER. TEMPS ARE EXPECTED TO REMAIN ABOVE CLIMO THROUGH TUE MRNG. PROFILES INDICATE AN ACCORDINGLY WARM COLUMN...AND THE MOISTURE WILL BE CONCENTRATED IN THE LOW TO MID LEVELS. ICE NUCLEATION AND SNOW PRODUCTION ARE UNLIKELY...SO WITH TEMPS REMAINING ABOVE FREEZING THROUGHOUT THE CWFA MON NIGHT NO MENTION OF WINTRY PRECIP HAS BEEN MADE. IN THE WAKE OF THE BOUNDARY DEEPER DRYING BEGINS LATER TUE AND CONTINUES THROUGH MID-WEEK...WITH SKIES TRENDING CLEARER. MAX TEMPS WILL RETURN TO AROUND CLIMO TUE FOLLOWED BY SIMILARLY NORMAL TEMPS FOR WED MRNG. DESPITE THE COLD ADVECTION...NOTABLY GUSTY WINDS ARE NOT EXPECTED WITH THE LEADING EDGE OF THE AIRMASS HAVING ALREADY PUSHED THROUGH. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 245 AM SUNDAY...REMARKABLY STRONG SFC HIGH PRESSURE OVER THE CENTRAL PLAINS GETS SHUNTED SWD AS NRN STREAM SHORTWAVE DIVES INTO THE MIDWEST AND PATTERN BEGINS TO REAMPLIFY OVER THE EAST. DRY AND SEASONABLY COOL WEATHER WILL CONTINUE FOR OUR AREA WED-THU WITH TEMPS NEAR CLIMO. THE SFC HIGH MOVES OVER THE SOUTHEAST BY THU NIGHT INITIATING RETURN FLOW INTO THE WRN GULF STATES AS THE CUTOFF LOW OVER THE DESERT SOUTHWEST PICKS UP SPEED. EVENTUALLY THAT WILL TRACK ACRS THE MIDDLE OR LOWER MISSISSIPPI VALLEY...SPINNING UP A NEW SYSTEM. AGREEMENT BETWEEN THE 28/00Z RUNS OF THE GFS AND EC IS GENERALLY GOOD...NOW ONLY SHOWING MINOR DIFFERENCES IN THE SFC LOW TRACK. REGARDLESS OF THE PRECISE TRACK PRECIP CHANCES BEGIN TO INCREASE THU NIGHT BEFORE PEAKING SATURDAY. MODELS HINT AT SOME PTYPE CONCERNS EARLY IN THE EVENT WITH A POSSIBLE IN-SITU CAD EVENT DEVELOPING...BUT THE BULK OF THE PRECIP SHOULD BE RAIN WITH TEMPS TRENDING ABOVE NORMAL BEYOND FRIDAY. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... AT KCLT...-RA HAS BEEN SLOW TO MATERIALIZE OVER THE TERMINAL THIS MORNING...REMAINING SOUTHWEST THROUGH SOUTHEAST OF THE TERMINAL THUS FAR. STILL EXPECT PERIODS OF -RA TO DEVELOP THIS MORNING...AS THE LOW LEVEL LIFT RESPONSIBLE FOR THE PRECIP GRADUALLY SHIFTS NORTH. HOWEVER...WITH SOME UNCERTAINTY REGARDING THE PRECIP POTENTIAL... THERE IS ALSO UNCERTAINTY AS TO HOW MUCH CIGS WILL LOWER LATER THIS MORNING. THE LATEST GUIDANCE HAS COME IN A LITTLE MORE OPTIMISTIC REGARDING THE IFR POTENTIAL...AND WE WILL CONTINUE TO HOLD OFF IFR CIGS UNTIL THE AFTERNOON. IN FACT...I/M BECMG LESS CONFIDENT THIS WILL EVEN WORK OUT...BUT DO NOT HAVE ENOUGH CONFIDENCE TO REMOVE THE IFR CIGS ALTOGETHER. EXPECT CONDITIONS TO IMPROVE TO MVFR OR VFR BY THIS EVENING. HOWEVER...CIGS WILL BEGIN TO LOWER AGAIN LATE TONIGHT AS LIFT INCREASES AGAIN IN RESPONSE TO APPROACHING UPPER AIR DISTURBANCE. MVFR CONDITIONS APPEAR TO BE A GOOD BET AFTER MIDNIGHT...AND WOULD NOT BE SURPRISED TO SEE IFR DEVELOP BY THE END OF THE PERIOD. WINDS SHOULD REMAIN LIGHT S/SW THROUGH MUCH OF THE PERIOD. ELSEWHERE...IFR OR EVEN LIFR CONDITIONS ARE EXPECTED TO PERSIST AT KAND THROUGH THE MORNING...ALONG WITH OCCL MVFR VISBY IN -RA. THESE CONDITIONS ARE EXPECTED TO DEVELOP AT KGSP/KGMU BY 15Z OR SO. THINGS ARE A BIT MORE UNCERTAIN AT THE NC TERMINALS...AS -RA HAS BEEN SLOW TO MATERIALIZE. IT APPEARS THAT -RA SHOULD EVENTUALLY DEVELOP AT KAVL...BUT WHETHER THIS WILL BE ENOUGH TO BRING THE CIGS DOWN INTO THE IFR RANGE IS UNCERTAIN. NEVERTHELESS...GUIDANCE CONTINUES TO INSIST THAT IFR CIGS WILL DEVELOP THERE...SO A TEMPO HAS BEEN INCLUDED DURING LATE MORNING. AT KHKY...FEEL A BIT MORE CONFIDENT IN HOLDING OFF ON THE IFR CONDITIONS UNTIL 18Z. EXPECT CONDITIONS TO IMPROVE TO MVFR OR VFR BY THIS EVENING. HOWEVER...CIGS WILL BEGIN TO LOWER AGAIN LATE TONIGHT AS LIFT INCREASES AGAIN IN RESPONSE TO APPROACHING UPPER AIR DISTURBANCE. MVFR CONDITIONS APPEAR TO BE A GOOD BET AFTER MIDNIGHT...AND WOULD NOT BE SURPRISED TO SEE IFR DEVELOP BY THE END OF THE PERIOD. OUTLOOK...PERIODS OF LIGHT RAIN AND FLIGHT RESTRICTIONS MAY LINGER MONDAY AND MONDAY NIGHT BEFORE GRADUAL IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD RETURN BY MID-WEEK. CONFIDENCE TABLE... 15-21Z 21-03Z 03-09Z 09-12Z KCLT MED 69% MED 72% LOW 52% HIGH 100% KGSP MED 69% MED 66% LOW 38% HIGH 90% KAVL MED 63% LOW 58% LOW 49% MED 73% KHKY HIGH 80% MED 61% LOW 38% MED 70% KGMU HIGH 83% MED 72% LOW 44% HIGH 83% KAND HIGH 83% LOW 47% LOW 33% HIGH 86% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...JDL/JOH SHORT TERM...WIMBERLEY LONG TERM...ARK/WIMBERLEY AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
918 AM EST SUN DEC 28 2014 .SYNOPSIS... A COLD FRONT WILL SLOWLY CROSS OUR REGION THROUGH MONDAY...THOUGH SOME MOISTURE WILL LINGER UNTIL TUESDAY. DRIER AND COOLER HIGH PRESSURE WILL MOVE ACROSS THE AREA WEDNESDAY AND THURSDAY. ANOTHER LOW PRESSURE SYSTEM THEN SHOULD BEGIN TO TAKE SHAPE AT THE END OF THE WEEK...BRINGING PRECIPITATION BACK TO THE AREA BY FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... 910 AM EST UPDATE...HAVE RAISED POPS TO 90/100 RANGE THIS MORNING OVER THE SOUTHERN HALF OF THE CWA PER LATEST RADAR TREND. THIS IS WELL IN LINE WITH THE LATEST HRRR WHERE THE HEAVIEST RAIN BAND WILL MOVE ACROSS ALONG AND SOUTHEAST OF THE I-85 THIS MORNING THRU MIDDAY. ALSO...HAVE INCLUDED AREAS OF PATCHY FOG TO ACCOUNT FOR THE LATEST SURFACE OBS. AS OF 645 AM...RAIN SHIELD HAS MADE VERY LITTLE NORTHWARD PROGRESS ABOVE (ROUGHLY) I-85 THIS MORNING...AND AM BEGINNING TO WONDER IF THE PRECIP ISN/T GOING TO JUST FIZZLE MORE OR LESS IN PLACE...AS UPGLIDE WEAKENS...AND THE MID-LEVELS DRY OUT. WILL CONTINUE TO FEATURE HIGH POPS (60-80) ACROSS OUR NC ZONES...BUT THESE HAVE BEEN SCALED BACK FROM THE EARLIER FORECAST. OTHERWISE...TEMPS ARE EXPECTED TO REMAIN MORE OR LESS STEADY THIS MORNING UNDER DENSE CLOUD COVER. AREA OF MODERATE RAIN IS FINALLY PUSHING ACROSS THE UPPER SAVANNAH RIVER VALLEY THIS MORNING. IN GENERAL...THIS IS FARTHER SOUTH THAN WHAT THE MODELS HAVE RECENTLY BEEN DEPICTING...AND THE HIGHEST QPF FOR THIS MORNING HAS BEEN ADJUSTED TO THE UPSTATE AND NORTHEAST GA...WHERE RAINFALL AMOUNTS THIS MORNING SHOULD RANGE FROM ONE QUARTER TO ONE HALF INCH...WITH LOCALLY HIGHER AMOUNTS. THE PRECIP SHIELD IS EXPECTED TO SHIFT NORTHWARD WITH TIME...AS THE BROAD BAND OF ISENTROPIC LIFT TRANSLATES NORTHEAST TOWARD THE MID-ATLANTIC. THEREFORE...THE MOUNTAINS AND FOOTHILLS OF WESTERN NC MAY YET SEE UP TO A HALF INCH OF RAINFALL THIS MORNING...WITH LIGHTER AMOUNTS TOWARD THE I-77 CORRIDOR. AS UPGLIDE SHUTS OFF AND MID-LEVELS DRY OUT THIS AFTERNOON...PRECIP SHOULD COME TO AN END...ALTHOUGH THE LOW LEVELS WILL REMAIN VERY MOIST AND THERE MAY BE PATCHES OF DRIZZLE OR LIGHT RAIN LINGERING. POPS WILL THEREFORE BE KEPT IN THE TOKEN CHANCE RANGE IN MOST AREAS THROUGH THE AFTERNOON. WITH PRECIP FALLING INTO A DRY AIR MASS THIS MORNING...FOLLOWED BY ABUNDANT LOW CLOUD COVER THROUGH THE AFTERNOON...A WEAK IN-SITU CAD EVENT MAY RESULT...AND MAX TEMPS ARE EXPECTED TO END UP BEING RATHER CLOSE TO CLIMO...DESPITE HIGH THICKNESS VALUES FOR THE TIME OF YEAR. A SHORT WAVE TROUGH EJECTING FROM TEXAS/THE LOWER MISS VALLEY TONIGHT WILL DAMPEN AS IT ENCOUNTERS THE CONFLUENT UPPER FLOW ACROSS THE EASTERN CONUS. NEVERTHELESS...A CONSENSUS OF MODEL GUIDANCE DEPICTS WEAK CYCLOGENESIS OCCURRING ALONG A BAROCLINIC ZONE ACROSS GEORGIA AND THE CAROLINAS...SUPPORTING ANOTHER ROUND OF RAINFALL LATE TONIGHT INTO EARLY MONDAY...AND WARRANTING CATEGORICAL POPS IN ALL AREAS ONCE AGAIN. ANOTHER ROUND OF .25-.50 INCH QPF APPEARS LIKELY IN MOST AREAS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 AM SUNDAY...PESKY FRONTAL ZONE FINALLY DOES LOOK TO BE FORCED SOUTH AND EAST OF THE CWFA MONDAY AS A CANADIAN AIRMASS EXPANDS OVER MOST OF THE ERN CONUS. COOLER AND DRIER AIR DO START TO FILTER IN BY MONDAY NIGHT...BUT SOME LLVL MOISTURE DOES LINGER INTO TUE. THE SOUTHEAST REMAINS UNDER BROADLY CYCLONIC FLOW THROUGH THAT TIME...WITH AN EMBEDDED SHORTWAVE PROGGED TO MOVE FROM THE MID MISSISSIPPI VALLEY TO THE DELMARVA BY TUE NIGHT. A WEAK BOUNDARY ASSOCIATED WITH THIS WAVE WILL ENHANCE COLD ADVECTION AND LLVL LIFT MON NIGHT/EARLY TUE...IN TIME TO ENCOUNTER THE MOISTURE. THUS POPS EXHIBIT A SECONDARY PEAK TUE MRNG. AS WINDS VEER TO NW AROUND THAT TIME...SOME UPSLOPE ENHANCEMENT IS ALSO EXPECTED WITH POPS TAKING A LITTLE LONGER TO TAPER OFF TUE NEAR THE TENN BORDER. TEMPS ARE EXPECTED TO REMAIN ABOVE CLIMO THROUGH TUE MRNG. PROFILES INDICATE AN ACCORDINGLY WARM COLUMN...AND THE MOISTURE WILL BE CONCENTRATED IN THE LOW TO MID LEVELS. ICE NUCLEATION AND SNOW PRODUCTION ARE UNLIKELY...SO WITH TEMPS REMAINING ABOVE FREEZING THROUGHOUT THE CWFA MON NIGHT NO MENTION OF WINTRY PRECIP HAS BEEN MADE. IN THE WAKE OF THE BOUNDARY DEEPER DRYING BEGINS LATER TUE AND CONTINUES THROUGH MID-WEEK...WITH SKIES TRENDING CLEARER. MAX TEMPS WILL RETURN TO AROUND CLIMO TUE FOLLOWED BY SIMILARLY NORMAL TEMPS FOR WED MRNG. DESPITE THE COLD ADVECTION...NOTABLY GUSTY WINDS ARE NOT EXPECTED WITH THE LEADING EDGE OF THE AIRMASS HAVING ALREADY PUSHED THROUGH. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 245 AM SUNDAY...REMARKABLY STRONG SFC HIGH PRESSURE OVER THE CENTRAL PLAINS GETS SHUNTED SWD AS NRN STREAM SHORTWAVE DIVES INTO THE MIDWEST AND PATTERN BEGINS TO REAMPLIFY OVER THE EAST. DRY AND SEASONABLY COOL WEATHER WILL CONTINUE FOR OUR AREA WED-THU WITH TEMPS NEAR CLIMO. THE SFC HIGH MOVES OVER THE SOUTHEAST BY THU NIGHT INITIATING RETURN FLOW INTO THE WRN GULF STATES AS THE CUTOFF LOW OVER THE DESERT SOUTHWEST PICKS UP SPEED. EVENTUALLY THAT WILL TRACK ACRS THE MIDDLE OR LOWER MISSISSIPPI VALLEY...SPINNING UP A NEW SYSTEM. AGREEMENT BETWEEN THE 28/00Z RUNS OF THE GFS AND EC IS GENERALLY GOOD...NOW ONLY SHOWING MINOR DIFFERENCES IN THE SFC LOW TRACK. REGARDLESS OF THE PRECISE TRACK PRECIP CHANCES BEGIN TO INCREASE THU NIGHT BEFORE PEAKING SATURDAY. MODELS HINT AT SOME PTYPE CONCERNS EARLY IN THE EVENT WITH A POSSIBLE IN-SITU CAD EVENT DEVELOPING...BUT THE BULK OF THE PRECIP SHOULD BE RAIN WITH TEMPS TRENDING ABOVE NORMAL BEYOND FRIDAY. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... AT KCLT...-RA HAS BEEN SLOW TO MATERIALIZE OVER THE TERMINAL THIS MORNING...REMAINING SOUTHWEST THROUGH SOUTHEAST OF THE TERMINAL THUS FAR. STILL EXPECT PERIODS OF -RA TO DEVELOP THIS MORNING...AS THE LOW LEVEL LIFT RESPONSIBLE FOR THE PRECIP GRADUALLY SHIFTS NORTH. HOWEVER...WITH SOME UNCERTAINTY REGARDING THE PRECIP POTENTIAL... THERE IS ALSO UNCERTAINTY AS TO HOW MUCH CIGS WILL LOWER LATER THIS MORNING. THE LATEST GUIDANCE HAS COME IN A LITTLE MORE OPTIMISTIC REGARDING THE IFR POTENTIAL...AND WE WILL CONTINUE TO HOLD OFF IFR CIGS UNTIL THE AFTERNOON. IN FACT...I/M BECMG LESS CONFIDENT THIS WILL EVEN WORK OUT...BUT DO NOT HAVE ENOUGH CONFIDENCE TO REMOVE THE IFR CIGS ALTOGETHER. EXPECT CONDITIONS TO IMPROVE TO MVFR OR VFR BY THIS EVENING. HOWEVER...CIGS WILL BEGIN TO LOWER AGAIN LATE TONIGHT AS LIFT INCREASES AGAIN IN RESPONSE TO APPROACHING UPPER AIR DISTURBANCE. MVFR CONDITIONS APPEAR TO BE A GOOD BET AFTER MIDNIGHT...AND WOULD NOT BE SURPRISED TO SEE IFR DEVELOP BY THE END OF THE PERIOD. WINDS SHOULD REMAIN LIGHT S/SW THROUGH MUCH OF THE PERIOD. ELSEWHERE...IFR OR EVEN LIFR CONDITIONS ARE EXPECTED TO PERSIST AT KAND THROUGH THE MORNING...ALONG WITH OCCL MVFR VISBY IN -RA. THESE CONDITIONS ARE EXPECTED TO DEVELOP AT KGSP/KGMU BY 15Z OR SO. THINGS ARE A BIT MORE UNCERTAIN AT THE NC TERMINALS...AS -RA HAS BEEN SLOW TO MATERIALIZE. IT APPEARS THAT -RA SHOULD EVENTUALLY DEVELOP AT KAVL...BUT WHETHER THIS WILL BE ENOUGH TO BRING THE CIGS DOWN INTO THE IFR RANGE IS UNCERTAIN. NEVERTHELESS...GUIDANCE CONTINUES TO INSIST THAT IFR CIGS WILL DEVELOP THERE...SO A TEMPO HAS BEEN INCLUDED DURING LATE MORNING. AT KHKY...FEEL A BIT MORE CONFIDENT IN HOLDING OFF ON THE IFR CONDITIONS UNTIL 18Z. EXPECT CONDITIONS TO IMPROVE TO MVFR OR VFR BY THIS EVENING. HOWEVER...CIGS WILL BEGIN TO LOWER AGAIN LATE TONIGHT AS LIFT INCREASES AGAIN IN RESPONSE TO APPROACHING UPPER AIR DISTURBANCE. MVFR CONDITIONS APPEAR TO BE A GOOD BET AFTER MIDNIGHT...AND WOULD NOT BE SURPRISED TO SEE IFR DEVELOP BY THE END OF THE PERIOD. OUTLOOK...PERIODS OF LIGHT RAIN AND FLIGHT RESTRICTIONS MAY LINGER MONDAY AND MONDAY NIGHT BEFORE GRADUAL IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD RETURN BY MID-WEEK. CONFIDENCE TABLE... 14-20Z 20-02Z 02-08Z 08-12Z KCLT MED 79% MED 68% LOW 56% HIGH 95% KGSP MED 64% MED 68% LOW 41% HIGH 100% KAVL MED 64% LOW 56% LOW 51% MED 72% KHKY MED 79% LOW 54% LOW 37% MED 70% KGMU MED 66% MED 68% LOW 45% HIGH 90% KAND MED 66% LOW 45% LOW 33% HIGH 90% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...JDL/JOH SHORT TERM...WIMBERLEY LONG TERM...ARK/WIMBERLEY AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1250 AM EST SUN DEC 28 2014 .SYNOPSIS... A SERIES OF SMALL LOW PRESSURE WILL MOVE NORTHEAST ALONG A COLD FRONT AS THE FRONT SLOWLY CROSSES OUR REGION FROM THE WEST THROUGH MONDAY. COOLER HIGH PRESSURE WILL BUILD OVER OUR REGION IN THE MID TO LATTER PART OF THE WEEK. ANOTHER LOW PRESSURE WILL GET ORGANIZED OVER TEXAS AND REACH OUR AREA NEXT WEEKEND. && .NEAR TERM /THROUGH TODAY/... AS OF 1245 AM...PLENTY OF LIGHT RADAR RETURNS ARE STILL TO BE SEEN ACROSS THE AREA EARLY THIS MORNING...BUT THUS FAR VERY LITTLE RAIN HAS FALLEN AS HYDROMETEORS ARE FALLING INTO A NEAR-SURFACE AIR MASS THAT REMAINS QUITE DRY. HOWEVER...HEAVIER PRECIPITATION IS OVERSPREADING NORTH GEORGIA FAIRLY QUICKLY...AND THIS WILL BEGIN TO SATURATE THE LOW LEVEL AIR MASS AS IT MOVES INTO OUR AREA OVER THE NEXT COUPLE OF HOURS. CATEGORICAL POPS STILL APPEAR TO BE A GOOD BET OVER THE WESTERN HALF OF THE AREA...WITH LIKELY POPS EAST. AS OF 920 PM...LATEST RADAR IMAGES FROM KGSP INDICATED LIGHT SHOWERS ACROSS THE LAKELANDS OF SC. UPSTREAM ACROSS CENTRAL AND NRN GA...COVERAGE OF LIGHT RAIN WAS INCREASING...ESPECIALLY NEAR THE AL/GA LINE. RECENT SATELLITE IMAGES INDICATED BKN TO OVC MID TO HIGH CLOUDS ACROSS THE CWA. THE THICK CLOUD COVER HAS LIKELY CONTRIBUTED TO KEEPING TEMPS ONE TO TWO DEGREES WARMER THAN THE CURRENT FORECAST. I WILL UPDATE THE FORECAST TO ADJUST POPS TO RECENT RADAR TRENDS...INCREASE SKY COVER...AND WARM HRLY TEMPS TO OBS. AS OF 710 PM...I WILL UPDATE TO FINE TUNE CLOUDS....TEMPS...AND POPS. WIDELY SCATTERED SHOWERS WILL LIKELY DEVELOP ACROSS THE UPPER SAVANNAH RIVER VALLEY THIS EVENING. OTHERWISE...MOIST SOUTHWEST LLVL WINDS WILL INCREASE ACROSS THE MTNS AND ADJACENT FOOTHILLS DURING THE PRE DAWN HOURS. THE COMBINATION OF UPSLOPE FLOW IN INCREASING LLVL LIFT SHOULD SUPPORT AN EXPANDING AREA OF LIGHT RAIN AND LOW CIGS TOWARD SUNRISE. AS OF 515 PM...LIGHT AND HIGH RADAR RETURNS WERE TRACKING ACROSS NRN GA. THESE RETURNS HAVE NOT BEEN ASSOCIATED WITH SFC OBS OF RAIN...EXPECTING RETURNS FROM VIRGA. HOWEVER...A LARGE PATCH OF LIGHT RAIN WAS DRIFTING ACROSS THE AL/GA LINE...THIS AREA SHOULD RESULT IN RAIN ACROSS THE CWA LATER TONIGHT. I WILL UPDATE TO ADJUST POP TIMING AND ALIGN TEMP/DWPT WITH OBSERVATIONS. AS OF 240 PM EST SATURDAY...THE LATEST SATELLITE IMAGE SHOWS A DEEP AND MOIST WARM CONVEYOR BELT EXTENDING FROM THE GREAT LAKES REGION DOWN TO THE WESTERN GULF...AND TO THE EASTERN PACIFIC...WITH BROAD AREAS OF CONVECTION DEVELOPING ACROSS THE DEEP SOUTH AS OF THIS AFTERNOON HOURS. AS AN EASTERN CONUS UPPER RIDGE AXIS PUSHES OFF THE ATLANTIC COAST AND MOIST SWLY FLOW ALOFT SETS UP OVER THE SOUTHEAST US...MID TO LOW LEVEL CLOUDS WILL SPREAD OVER THE PIEDMONT THROUGH THE AFTERNOON HOURS.THE LATEST SHORT TERM MODELS CONTINUE TO INDICATE THAT A COLD FRONT WILL SLOWLY MOVE EAST ACROSS THE MISSISSIPPI VALLEY AND INTO THE TN VALLEY TONIGHT INTO SUN MORNING...REACHING THE SOUTHERN APPALACHIANS BY SUN AFTERNOON. AHEAD OF THIS FRONT...A DEEP PLUME OF GULF MOISTURE WILL BE DRAWN UP INTO THE REGION AS A WAVE OF LOW OVER THE WESTERN GULF LIFTS NE ACROSS AL/MI TONIGHT. THEREFORE...POPS QUICKLY RAMP UP FROM WEST TO EAST INTO THE CATEGORICAL RANGE OVER THE WESTERN MTNS ZONES AND NE GA...WITH LIKELY RANGE OVER THE REST OF THE WESTERN HALF OF THE CWA. THE BEST RAINFALL RATES WILL OCCUR BETWEEN 12Z-18Z SUN WHEN THE SURFACE WAVE OF LOW LIFTS NE ACROSS THE CWA AND A SERIES OF UPPER DISTURBANCES RIPPLES ACROSS THE MTNS ZONES IN SWLY FLOW ALOFT. ALSO...HAVE MENTIONED A CHANCE OF THUNDER ACROSS MUCH OF THE REGION EARLY SUN AFTERNOON DUE TO THE PRESENCE OF 100-200J/KG MUCAPE PER LATEST NAM/GFS/ECMWF. POPS RAMP DOWN TO THE LIKELY RANGE OVER THE MTN ZONES AND SOLD CHANCE RANGE OVER THE SOUTHERN TIER OF THE REGION 18Z THRU 00Z MON AS THE UPPER FORCING AND THE SURFACE WAVE OF LOW MOVES OFF TO THE NE. WITH MODELS TRENDING A BIT WETTER FOR THE UPCOMING EVENT...HAVE GONE WITH THE HPC QPF GUIDANCE RESULTING IN 0.75-1.0" OVER THE WESTERN NC MTNS AND NE GA... WITH AROUND 0.25-0.5" ELSEWHERE THRU SUN EVENING. WITH CONSIDERABLE CLOUD COVER AND WAA SOUTHERLY FLOW...OVERNIGHT TEMPS WILL STAY 7-10 DEGREES ABOVE NORMAL. WITH ONGOING PRECIP...AFTERNOON HIGHS ON SUN WILL BE AROUND 3-5 DEGREES COOLER THAN TODAY. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... AS OF 200 PM SATURDAY...THE MODELS SUGGEST THAT WE WILL BE IN A LULL OF SORTS AT THE START OF THE SHORT RANGE PERIOD SUNDAY EVENING...AS WE WILL BE IN A MINIMUM OF FORCING. THAT CHANGES QUICKLY BY LATE EVENING AS THE RIGHT ENTRANCE REGION OF THE UPPER JET TRANSLATES OVERHEAD BETWEEN ROUGHLY 03Z AND 09Z...AND THE MAIN SHORT WAVE AXIS MOVES THROUGH IN THE 06Z TO 12Z MONDAY TIME FRAME. ALTHO THE WAVE SHEARS AND DEAMPLIFIES AS IT CROSSES THE REGION...THE FORCING SHOULD STILL BE SUFFICIENT TO INCREASE PRECIP PRODUCTION...COMBINED WITH IMPROVED MOIST ISENTROPIC LIFT. SO...PRECIP CHANCES RAMP BACK UP TO CATEGORICAL MAINLY OVER THE AREA ALONG AND N/W OF I-85...AND LIKELY TO THE S...BY 06Z OR SO. THE MAIN FORCING SHOULD SHIFT E OF THE AREA MONDAY MORNING. THE HIGHEST PRECIP PROBABILITY WILL BE OVER THE WRN NC PIEDMONT ON MONDAY MORNING. POP WAS LIMITED TO LIKELY OUT OF UNCERTAINTY WITH TIMING THE DEPARTURE OF THE FORCING...BUT COULD EASILY HAVE TO BE KEPT CATEGORICAL BEYOND 12Z MONDAY WITH THE SLIGHTEST DELAY. THE REST OF MONDAY WILL HAVE A SLOW RAMP DOWN THROUGH THE CHANCE RANGE AS FORCING GRADUALLY WEAKENS BEHIND THE SURFACE FRONT THAT CROSSES FIRST THING IN THE DAY. FOR MONDAY NIGHT AND TUESDAY...THERE IS UNCERTAINTY REGARDING THE EXTENT/CHANCE OF PRECIP. THE LOW LEVEL FLOW COMES AROUND TO SOMETHING NW MONDAY NIGHT AND TUESDAY WHICH SHOULD FORCE SOME SHOWER ACTIVITY NEAR THE TN BORDER. THE PASSAGE OF ANOTHER SHORT WAVE COMBINED WITH SOME LOW LEVEL FRONTOGENESIS APPEARS TO BE RESPONSIBLE FOR THE REDEVELOPMENT OF PRECIP ON TUESDAY OFF TO OUR N...WHICH SOME OF THE GUIDANCE BLEEDS DOWN INTO NC. PREFER TO KEEP THE BETTER CHANCES IN THE UPSLOPE AREAS OF THE NRN MTNS AND TO KEEP THE AREA E OF THE BLUE RIDGE DRY FOR THE TIME BEING. TEMPS SHOULD DROP BACK DOWN TO NEAR NORMAL ON TUESDAY. ON SUNDAY THE FAIRLY BROAD FRONTAL ZONE WILL EXTEND FROM QUEBEC SWWD TO THE WRN GULF COAST...BISECTING THE TENN VALLEY JUST TO OUR WEST. AT LEAST ONE WEAK WAVE IS PROGGED TO RIDE UP THE FRONT DURING THE DAY AS A RESULT OF CYCLONIC UPPER FLOW OVER THE BOUNDARY CONTAINING EMBEDDED WEAK VORTICES. THOUGH SUCH A WAVE WOULD LIKELY PROVIDE LOCAL ENHANCEMENT TO LLVL WARM/MOIST ADVECTION AHEAD OF THE FRONT...THE EXISTENCE OF ONE IS IN QUESTION GIVEN THE POOR AGREEMENT AND CONSISTENCY FROM GUIDANCE ON HOW THIS OCCURS. OVERALL THE FORCING SUNDAY IS JUST NOT ALL THAT IMPRESSIVE. LITTLE TO NO INSTABILITY IS PROGGED OVER THE CWFA AND THOUGH A GOOD SLUG OF MOISTURE TRANSPORT IS PRESENT ON NAM/GFS PROGS THE LLVL LIFT IS LIMITED. AT ANY RATE...THRU SUNDAY THE FRONT REMAINS NEARLY STATIONARY ACRS THE SOUTHEAST...THE PARENT LOW CONTINUING TO PROGRESS EWD WITH THE ACTIVE NRN STREAM WHILE THE BROAD SRN STREAM TROUGH IS HELD OFF BY THE BERMUDA HIGH. IT APPEARS THE FRONT WILL NOT ACTUALLY ENTER THE AREA UNTIL MONDAY MRNG...WITH A DISTINCT 500MB SHORTWAVE ACCOMPANYING IT AS WELL AS UPPER DIVERGENCE ASSOC WITH RR QUAD OF A JET STREAK. TWO PEAKS OF PRECIP ACTIVITY ARE SUGGESTED WHEN THE TOTAL FORCING IS MAXIMIZED...SUNDAY MRNG AND THEN EARLY MON MRNG. HOWEVER IT IS DIFFICULT TO PICK OUT A POINT BETWEEN WHERE A LULL SHOULD BE BETWEEN...WITH THE OVERALL PATTERN REMAINING FAVORABLE FOR AT LEAST LIGHT PRECIP. WILL CONTINUE TO ADVERTISE LIKELY POPS MOST OF THE AREA THROUGHOUT SUNDAY...BUT CONCENTRATING MORE QPF CLOSE TO THE AFOREMENTIONED PEAKS. DESPITE CLOUDS AND RAIN...IN THE WARM AIRMASS TEMPS SHOULD TOP OUT 5-9 DEGREES ABOVE NORMAL SUN AFTN...WITH MINS MON MRNG BEING EVEN MORE ABOVE NORMAL...UPPER 40S AND LOWER 50S. MAX TEMPS MONDAY WILL BE SLIGHTLY WARMER THAN SUNDAY OVER THE PIEDMONT WITH THE FRONT NOT YET HAVING AN IMPACT. PROGRESSION OF THE UPPER PATTERN IS STILL PRETTY SLOW THRU MON NIGHT...WITH THE CWFA NEAR THE INFLECTION POINT BETWEEN THE PLAINS TROUGH AND THE ATLANTIC RIDGE. POPS DECLINE ONLY GRADUALLY THRU THE END OF THE PERIOD WITH MOST OF THE GUIDANCE INDICATING SOME QPF CONTINUING ON THE BACK SIDE OF ANOTHER FRONTAL WAVE DEVELOPING NEAR THE GA/SC COAST. COLDER AIR WILL BEGIN TO RETURN TO ALL AREAS ON THE ENSUING NLY FLOW MON NIGHT...THOUGH MIN TEMPS WILL STILL BE AROUND 10 DEGREES ABOVE CLIMO. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 215 PM SATURDAY...THE MEDIUM RANGE WILL START OUT WITH SPLIT UPPER LVL FLOW...WITH A LARGE POLAR VORTEX SPINNING OVR HUDSON BAY...AND A CUTOFF LOW INVOF CALIFORNIA. THE MODEL GUIDANCE HAS BEEN SLOWLY CONVERGING ON THE TIMING OF THE CUTOFF LOW BEING EJECT ACRS INTO THE SOUTHERN STREAM AROUND FRIDAY. HOWEVER...THERE IS STILL SOME DISAGREEMENT ON THAT...WITH THE GFS CONSISTENTLY FASTER/EARLIER...AND THE ECMWF SLOWER/DEEPER. THE LATEST WPC PREFERENCE IS WITH THE ENSEMBLE MEAN...SLOWER THAN THE GFS...AND NOT AS DEEP WITH THE RESULTED PROGRESSIVE SHORTWAVE TROF AS THE ECMWF. AT THE SFC...A BROAD AREA OF CANADIAN HIGH PRES WILL ENCOMPASS ABOUT 3/4TH OF THE CONUS ON WEDNESDAY...GRADUALLY MODIFYING AND DRIFTING EAST WITH THE CENTER CROSSING THE CWFA EARLY FRIDAY. DRY WEATHER AND SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED WEDNESDAY THRU THURSDAY NIGHT. AS THE EJECTING UPPER TROF FINALLY ENTERS THE SOUTHERN PLAINS...A LOW PRES SYSTEM SHUD BEGIN TO ORGANIZE...TAPPING INTO COPIOUS GULF MOISTURE. POPS WILL THEN RAMP UP BY NEXT WEEKEND. OF COURSE...EXACT TIMING IS STILL THE MAIN QUESTION. THE 12Z GFS AND ECMWF BOTH SHOW POSSIBLE WINTRY MIX PRECIP TYPE CONCERNS AT ONSET FRIDAY MORNING...BUT THEN TURNING OVER TO ALL RAIN...AS STRONG SWLY WAA SHUD DOMINATE ANY LINGERING IN SITU COLD AIR DAMMING. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AT KCLT...THE OVERNIGHT/EARLY MORNING HOURS WILL SEE LOWERING CIGS...WITH LOW VFR CONDITIONS EXPECTED BY DAYBREAK...AND INCREASING CHANCES FOR -RA. ONCE THE -RA OVERSPREADS THE AREA LATER THIS MORNING...SATURATION OF THE LOW LEVEL AIR MASS SHOULD RESULT IN MVFR CIGS DEVELOPING BY MID-MORNING...WITH IFR EXPECTED BY EARLY AFTERNOON. CIGS WILL THEN BE SLOW TO IMPROVE...BUT WE MAY SEE BRIEF IMPROVEMENT TO MVFR OR EVEN VFR BY SUNDAY EVENING...JUST IN TIME FOR ANOTHER ROUND OF -RA TO OVERSPREAD THE AREA. WINDS WILL GENERALLY REMAIN LIGHT OUT OF THE SW...ALTHOUGH THEY MAY GO LIGHT/VRBL OR CALM AFTER THE PRECIP SETS IN LATER THIS MORNING. ELSEWHERE...-RA WILL GRADUALLY OVERSPREAD THE TERMINALS OVER THE NEXT 2-4 HOURS. CIGS SHOULD ALSO LOWER DURING THAT WINDOW...WITH MVFR CONDITIONS LIKELY AT MOST TERMINALS BY DAYBREAK. PERIODS OF REDUCED VISBY WILL ALSO BECOME MORE LIKELY BY THAT TIME. IFR CONDITIONS WILL BE MOST LIKELY AT KAND AND KAVL PRIOR TO 12Z...AND TEMPOS HAVE BEEN INCLUDED TO ACCOUNT FOR THIS. OTHERWISE...CIGS SHOULD REDUCE TO IFR OR EVEN LOWER BY MID-MORNING AT MOST TERMINALS. IMPROVEMENT WILL BE SLOW...BUT WE MAY SEE BRIEF MVFR OR EVEN VFR CONDITIONS BY SUNDAY EVENING...JUST IN TIME FOR ANOTHER ROUND OF -RA TO OVERSPREAD THE AREA. OUTLOOK...PERIODS OF RAIN AND FLIGHT RESTRICTIONS MAY LINGER FROM LATE SUNDAY NIGHT THROUGH MONDAY NIGHT BEFORE GRADUAL IMPROVEMENT OCCURS THROUGHOUT TUESDAY. DRY HIGH PRESSURE SHOULD RETURN BY MID- WEEK. CONFIDENCE TABLE... 06-12Z 12-18Z 18-24Z 00-06Z KCLT HIGH 100% HIGH 94% HIGH 87% HIGH 80% KGSP HIGH 94% LOW 52% LOW 59% LOW 56% KAVL MED 66% LOW 52% LOW 55% HIGH 83% KHKY HIGH 100% MED 68% LOW 50% LOW 48% KGMU HIGH 96% LOW 59% MED 60% MED 60% KAND HIGH 85% HIGH 93% LOW 52% MED 70% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...JDL/NED SHORT TERM...PM LONG TERM...ARK AVIATION...JDL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1125 PM CST SAT DEC 27 2014 .AVIATION 06Z DISCUSSION... INVERTED SFC TROUGH TO CONTINUE PUSHING SLOWLY EASTWARD ACROSS THE MID STATE TONIGHT. PLENTY OF MOISTURE...BOTH IN ADVANCE AND BEHIND THE TROUGH...WILL ALLOW FOR A CONTINUATION OF RAINFALL THROUGH THE TAF PD. AS A RESULT...LOW CIGS AND VSBYS WILL PERSIST. RAINFALL COVERAGE WILL LET UP AFT 18Z. BY 00Z SHOULD JUST BE LOOKING AT VCSH ACROSS THE BNA AND CKV AREAS. CIGS WILL REMAIN LOW THROUGH THE TAF PD. && .PREV DISCUSSION... /ISSUED 732 PM CST SAT DEC 27 2014/ DISCUSSION... INVERTED TROUGH AXIS APPROACHING WESTERN MIDDLE TN AT THIS TIME. A MARKED DECREASE IN COVERAGE IS NOTED ACROSS WESTERN PORTIONS OF THE CWA. HOWEVER...LATEST RADAR TRENDS AND THE HRRR INFORMATION BOTH SUGGEST THAT PRECIP COVERAGE WILL FILL IN ALONG AND WEST OF THE ADVANCING TROUGH. A CLOSER LOOK DOES REVEAL SOME APPRECIABLE SEPARATION IN REGARD TO THE 850 MB AND SFC FRONT. FURTHERMORE...THE GREATER LOW LEVEL FORCING RESIDES ALONG THE 850 MB FRONT WHERE THE ANGULAR CONVERGENCE IS GREATER. FOR THE FCST...DESPITE THE CURRENT DECREASE IN COVERAGE...WILL CONTINUE WITH THE CATEGORICAL POPS AS WAS MENTIONED EARLIER...THE COVERAGE SHOULD FILL BACK IN. NO CHANGES FOR NOW TO THE FCST. PREV DISCUSSION... /ISSUED 510 PM CST SAT DEC 27 2014/ AVIATION 00Z DISCUSSION... INVERTED SFC TROUGH TO PUSH SLOWLY EASTWARD ACROSS THE MID STATE TONIGHT. PLENTY OF MOISTURE...BOTH IN ADVANCE AND BEHIND THE TROUGH...WILL ALLOW FOR A CONTINUATION OF RAINFALL THROUGH THE TAF PD. AS A RESULT...LOW CIGS AND VSBYS WILL PERSIST. RAINFALL COVERAGE WILL LET UP SOME AS WE APPROACH THE END OF THE TAF PD...BETWEEN 18Z AND 00Z. PREV DISCUSSION... /ISSUED 304 PM CST SAT DEC 27 2014/ DISCUSSION... LOCAL AND REGIONAL RADAR IMAGERY SHOW WIDESPREAD RAIN SHOWER COVERAGE STRETCHING FROM MIDDLE TENNESSEE BACK TO THE LOUISIANA- TEXAS BORDER...AND SOUTH TO THE GULF COAST. THESE SHOWERS ARE ASSOCIATED WITH AN AREA OF LOW LEVEL CONVERGENCE...WHICH AS IT APPROACHES THE MID-STATE WILL BECOME ALIGNED WITH AN UPPER LEVEL JET STREAK. LIGHTNING COVERAGE HAS DIMINISHED...AND WITH FORECAST MODELS SHOWING LAPS RATES BELOW 6 DEGREES HAVE REMOVED IT FROM THE FORECAST. AFTER THE STEADY RAIN MOVES THROUGH TONIGHT...A BRIEF PERIOD OF LITTLE IF ANY SHOWER ACTIVITY IS EXPECTED FOR SUNDAY...MAINLY IN THE AFTERNOON HOURS AND ESPECIALLY ACROSS THE NORTHWEST COUNTIES. FOR SUNDAY NIGHT SHOWER ACTIVITY IS EXPECTED TO RETURN...WITH ANOTHER SHORTWAVE TRACKING FROM THE LOUISIANA- TEXAS BORDER TO NORTH CAROLINA BY MONDAY MORNING. THE BETTER MOISTURE AXIS AND UPPER LEVEL SUPPORT...WHILE MINIMAL...FAVOR THE SOUTHERN AND EASTERN AREAS. THE NORTHWEST COUNTIES WILL JUST HAVE SLIGHT TO LOW CHANCE POPS FOR SUNDAY NIGHT...AND MAY EVEN BE COMPLETELY DRY. THIS SOUTHERLY TRACK WILL BRING STORM TOTAL RAINFALL AMOUNTS FOR AREAS MAINLY ALONG AND SOUTH OF I-40 TO AROUND AN INCH TO AN INCH AND A HALF BY MONDAY MORNING. A SECONDARY FRONT WITH MUCH MORE NOTABLE COLD AIR ADVECTION PUSHES THROUGH THE MID-STATE WEDNESDAY...AND LINGERS THROUGH THURSDAY. THE LONG-RANGE MODELS INDICATE A MUCH STRONGER SHORTWAVE DEVELOPING OVER TEXAS BY SATURDAY MORNING...AND TRACKING THROUGH THE OHIO RIVER VALLEY BY SUNDAY EVENING. THE WARM FRONT SURGE OUT AHEAD OF IT ARRIVES THURSDAY NIGHT...SO WITH THE AFOREMENTIONED COLD AIR IN PLACE SOME MIXED PRECIPITATION IS POSSIBLE...EVEN A PERIOD OF SNOW DURING THE OVERNIGHT HOURS...MAINLY OVER THE SOUTHWESTERN COUNTIES. BY FRIDAY MORNING...TEMPERATURES WARM ABOVE FREEZING AND STEADY RAIN IS EXPECTED TO LINGER THROUGH FRIDAY NIGHT AND POSSIBLY INTO SATURDAY PER THE ECMWF. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 45 45 36 49 / 100 80 70 10 CLARKSVILLE 41 42 33 47 / 100 60 20 10 CROSSVILLE 47 51 40 49 / 100 100 90 20 COLUMBIA 46 47 37 51 / 100 80 70 10 LAWRENCEBURG 47 49 37 51 / 100 80 90 10 WAVERLY 42 43 33 48 / 100 80 50 10 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
907 PM CST MON DEC 29 2014 .UPDATE... WINDS BEGAN BACKING AT SUNSET AND WILL CONTINUE OVERNIGHT AS COLDER AIR OVER OKLAHOMA/KANSAS SPREADS SOUTH. HAVE UPDATED TO OVERNIGHT SKY GRIDS FOR MOSTLY CLEAR CONDITIONS OVER THE NORTHWEST THIRD THROUGH MIDNIGHT. LOW CLOUDS OVER EAST TEXAS HAVE ALREADY REACHED A PARIS-GREENVILLE-FAIRFILED LINE AND WILL CONTINUE TO MOVE WESTWARD OVERNIGHT. LOW TEMPERATURES TONIGHT SEEM REASONABLE CONSIDERING THE INCREASING CLOUD COVER AND COLD AIR ADVECTION. AS FOR THE WINTRY PRECIPITATION EVENT TUESDAY NIGHT THROUGH THURSDAY MORNING...TONIGHT/S NAM RUN DOES NOT ADD OR SUBTRACT ANY CONFIDENCE RELATED TO THE POTENTIAL FOR SOME FORM OF A WINTRY MIX TO DEVELOP DURING THE TIME PERIOD. ALTHOUGH THE MODELS ARE COLD ENOUGH FOR FREEZING RAIN OR SLEET TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...MODEL QPF REMAINS LOW AND JUST A FEW HUNDREDTHS OF AN INCH UNTIL NEW YEARS DAY WHEN QPF POTENTIAL INCREASES DUE INCREASED WARM AIR ADVECTION ALOFT AND SYNOPTIC LIFT FROM AN APPROACHING SHORTWAVE TO THE WEST. THUS...WE WILL ALLOW THE FORECAST FOR TUESDAY AND BEYOND TO REMAIN AS IS AND ISSUE AN UPDATED ZONE PACKAGE TO INCLUDE THE SKY COVER CHANGES FOR THE REST OF THE EVENING THROUGH ABOUT 2 AM IN THE MORNING. 75 && .AVIATION... /ISSUED 548 PM CST MON DEC 29 2014/ MAIN CONCERN IN TAF FORECAST IS THE POTENTIAL FOR LOW CIGS TONIGHT. RESIDUAL FOG BANK TO THE EAST OF TAF SITES HAS LIFTED TO A CLOUD BANK OF IFR CIGS. AS A SURFACE LOW DROPS INTO CENTRAL TEXAS WINDS WILL BACK FROM THE SOUTHEAST TO THE NORTHEAST THIS EVENING. THIS WILL BRING THESE CLOUDS AND HIGHER LOW LEVEL MOISTURE INTO THE TAF SITES. HRRR BRINGS IFR INTO METROPLEX AFTER 1Z...WHILE THE RUC/NAM HOLD OFF UNTIL AFTER MIDNIGHT. THE GFS HAS NO CIGS AND DID NOT RECOGNIZE THE EXTENT OF LOW LEVEL MOISTURE AVAILABLE. WILL SIDE WITH NAM/RUC TIMING. OTHERWISE ARCTIC FRONT WILL MOVE THROUGH TONIGHT...BUT FRONTAL PASSAGE WILL BE AMBIGUOUS AS THE ONLY NOTICEABLE CHANGE WILL BE RISING PRESSURE AND A GRADUAL TURN OF THE WINDS TO THE NORTH BY DAYBREAK. WILL BRING LOW CIGS UP GRADUALLY TOMORROW...WITH MVFR BY MID-MORNING AND VFR BY MID-AFTERNOON FOR METROPLEX SITES. AT WACO CIGS WILL LIKELY HANG IN AT MVFR THROUGH THE AFTERNOON. TR.92 && .PREV DISCUSSION... /ISSUED 305 PM CST MON DEC 29 2014/ 06Z GUIDANCE CAME IN WETTER THAN PREVIOUS...PUTTING US IN THE MIND FRAME TO INCREASE THE ICE POTENTIAL IN THE WEST...BUT THE 12Z RUN CAME BACK DRIER AGAIN AND THEREFORE THIS FORECAST HAS LOW POPS IN THE WEST THROUGH WEDNESDAY...AND LITTLE WINTER WEATHER ACCUMULATIONS. ALTHOUGH PRECIPITATION TYPE IS STILL A BIT UNCERTAIN...WE THINK QPF WILL REMAIN QUITE LOW BECAUSE THERE IS NO SOURCE OF LARGE SCALE LIFT PROGGED UNTIL THURSDAY MORNING WHEN A STRONG SHORT WAVE MOVES ACROSS THE AREA. BY EARLY WEDNESDAY MORNING THE LOW LEVELS ARE FAIRLY SATURATED IN OUR WESTERN COUNTIES. DRIZZLE DROPS ARE EXPECTED TO FORM AND FALL THROUGH A SHALLOW BELOW-FREEZING LAYER AT AND JUST ABOVE THE SURFACE. WE HAVE GONE WITH A DRIZZLE/FREEZING RAIN MIX BECAUSE THERE ARE PERIODS WHERE THE DROPLETS CAN BE BIG ENOUGH TO BE CALLED FREEZING RAIN. THERE MAY BE SOME SLEET MIXED IN AS WELL AS THE SLOWLY FALLING SMALLER DROPS MAY HAVE TIME TO FREEZE IN THE AIR JUST ABOVE THE SURFACE. WE WENT WITH THE TWO MOST LIKELY PRECIP TYPES IN THE GRIDS BUT THIS MAY CHANGE AS LATER RUNS CHANGE TEMPERATURE PROFILES. TEMPERATURES WILL RISE ABOVE FREEZING WEDNESDAY AFTERNOON...BUT FALL BELOW FREEZING AGAIN INTO THURSDAY MORNING ACROSS MOST OF THE NORTHWESTERN HALF OF NORTH/CENTRAL TEXAS. BEFORE SUNRISE...THE LIFT ASSOCIATED WITH A SHORT WAVE DISTURBANCE ROTATING AROUND THE UPPER LOW WILL INCREASE MOISTURE ABOVE THE INVERSION...WARM THE AIR COLUMN ALOFT...AND PRODUCE ISENTROPIC LIFT INITIALLY IN OUR SOUTHWESTERN COUNTIES. PRECIP SHOULD FALL AS FREEZING RAIN INITIALLY IN BELOW FREEZING AREAS AND THEN TRANSITION TO RAIN ACROSS THE CWA BY EARLY AFTERNOON. COUNTIES SOUTHEAST OF A LINE FROM TEMPLE TO CORSICANA TO BONHAM WILL LIKELY BE ABOVE FREEZING BEFORE THE PRECIP STARTS. IN NORTHWEST COUNTIES WHERE COLD AIR IS EXPECTED TO BE DEEPER...PRECIP TYPE MAY BEGIN AS SLEET AND THEN TRANSITION TO FREEZING RAIN...THEN RAIN. CHANGEOVER TIMING WILL HINGE ON INITIAL TEMPERATURES...TIMING OF THE SHORT WAVE...AND WARMING OF THE LOW LEVELS DUE TO RAIN FALLING FROM THE WARM NOSE THAT DEVELOPS THURSDAY. A SECOND ROUND OF PRECIPITATION...ALL LIQUID...WILL BEGIN OVERNIGHT INTO FRIDAY MORNING. SHOWERS WITH SOME ISOLATED EMBEDDED THUNDER WILL CONTINUE UNTIL SATURDAY MORNING AS THE SYSTEM PUSHES EAST. AS RIDGING DEVELOPS OVER THE AREA...NORTH/CENTRAL TX SHOULD REMAIN COOL AND DRY THROUGH EARLY NEXT WEEK. 84 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 33 42 27 35 32 / 5 5 5 10 20 WACO, TX 34 45 29 38 32 / 5 5 5 10 30 PARIS, TX 30 43 25 40 31 / 5 5 5 10 10 DENTON, TX 30 41 23 34 29 / 5 5 5 10 20 MCKINNEY, TX 29 42 24 35 31 / 5 5 5 10 20 DALLAS, TX 34 43 28 35 33 / 5 5 5 10 20 TERRELL, TX 32 44 28 37 33 / 5 5 5 10 20 CORSICANA, TX 36 45 29 39 34 / 5 5 5 10 30 TEMPLE, TX 35 46 29 38 32 / 5 5 5 10 30 MINERAL WELLS, TX 29 38 22 33 28 / 5 10 10 20 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /75
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
548 PM CST MON DEC 29 2014 .AVIATION... MAIN CONCERN IN TAF FORECAST IS THE POTENTIAL FOR LOW CIGS TONIGHT. RESIDUAL FOG BANK TO THE EAST OF TAF SITES HAS LIFTED TO A CLOUD BANK OF IFR CIGS. AS A SURFACE LOW DROPS INTO CENTRAL TEXAS WINDS WILL BACK FROM THE SOUTHEAST TO THE NORTHEAST THIS EVENING. THIS WILL BRING THESE CLOUDS AND HIGHER LOW LEVEL MOISTURE INTO THE TAF SITES. HRRR BRINGS IFR INTO METROPLEX AFTER 1Z...WHILE THE RUC/NAM HOLD OFF UNTIL AFTER MIDNIGHT. THE GFS HAS NO CIGS AND DID NOT RECOGNIZE THE EXTENT OF LOW LEVEL MOISTURE AVAILABLE. WILL SIDE WITH NAM/RUC TIMING. OTHERWISE ARCTIC FRONT WILL MOVE THROUGH TONIGHT...BUT FRONTAL PASSAGE WILL BE AMBIGUOUS AS THE ONLY NOTICEABLE CHANGE WILL BE RISING PRESSURE AND A GRADUAL TURN OF THE WINDS TO THE NORTH BY DAYBREAK. WILL BRING LOW CIGS UP GRADUALLY TOMORROW...WITH MVFR BY MID-MORNING AND VFR BY MID-AFTERNOON FOR METROPLEX SITES. AT WACO CIGS WILL LIKELY HANG IN AT MVFR THROUGH THE AFTERNOON. TR.92 && .PREV DISCUSSION... /ISSUED 305 PM CST MON DEC 29 2014/ 06Z GUIDANCE CAME IN WETTER THAN PREVIOUS...PUTTING US IN THE MIND FRAME TO INCREASE THE ICE POTENTIAL IN THE WEST...BUT THE 12Z RUN CAME BACK DRIER AGAIN AND THEREFORE THIS FORECAST HAS LOW POPS IN THE WEST THROUGH WEDNESDAY...AND LITTLE WINTER WEATHER ACCUMULATIONS. ALTHOUGH PRECIPITATION TYPE IS STILL A BIT UNCERTAIN...WE THINK QPF WILL REMAIN QUITE LOW BECAUSE THERE IS NO SOURCE OF LARGE SCALE LIFT PROGGED UNTIL THURSDAY MORNING WHEN A STRONG SHORT WAVE MOVES ACROSS THE AREA. BY EARLY WEDNESDAY MORNING THE LOW LEVELS ARE FAIRLY SATURATED IN OUR WESTERN COUNTIES. DRIZZLE DROPS ARE EXPECTED TO FORM AND FALL THROUGH A SHALLOW BELOW-FREEZING LAYER AT AND JUST ABOVE THE SURFACE. WE HAVE GONE WITH A DRIZZLE/FREEZING RAIN MIX BECAUSE THERE ARE PERIODS WHERE THE DROPLETS CAN BE BIG ENOUGH TO BE CALLED FREEZING RAIN. THERE MAY BE SOME SLEET MIXED IN AS WELL AS THE SLOWLY FALLING SMALLER DROPS MAY HAVE TIME TO FREEZE IN THE AIR JUST ABOVE THE SURFACE. WE WENT WITH THE TWO MOST LIKELY PRECIP TYPES IN THE GRIDS BUT THIS MAY CHANGE AS LATER RUNS CHANGE TEMPERATURE PROFILES. TEMPERATURES WILL RISE ABOVE FREEZING WEDNESDAY AFTERNOON...BUT FALL BELOW FREEZING AGAIN INTO THURSDAY MORNING ACROSS MOST OF THE NORTHWESTERN HALF OF NORTH/CENTRAL TEXAS. BEFORE SUNRISE...THE LIFT ASSOCIATED WITH A SHORT WAVE DISTURBANCE ROTATING AROUND THE UPPER LOW WILL INCREASE MOISTURE ABOVE THE INVERSION...WARM THE AIR COLUMN ALOFT...AND PRODUCE ISENTROPIC LIFT INITIALLY IN OUR SOUTHWESTERN COUNTIES. PRECIP SHOULD FALL AS FREEZING RAIN INITIALLY IN BELOW FREEZING AREAS AND THEN TRANSITION TO RAIN ACROSS THE CWA BY EARLY AFTERNOON. COUNTIES SOUTHEAST OF A LINE FROM TEMPLE TO CORSICANA TO BONHAM WILL LIKELY BE ABOVE FREEZING BEFORE THE PRECIP STARTS. IN NORTHWEST COUNTIES WHERE COLD AIR IS EXPECTED TO BE DEEPER...PRECIP TYPE MAY BEGIN AS SLEET AND THEN TRANSITION TO FREEZING RAIN...THEN RAIN. CHANGEOVER TIMING WILL HINGE ON INITIAL TEMPERATURES...TIMING OF THE SHORT WAVE...AND WARMING OF THE LOW LEVELS DUE TO RAIN FALLING FROM THE WARM NOSE THAT DEVELOPS THURSDAY. A SECOND ROUND OF PRECIPITATION...ALL LIQUID...WILL BEGIN OVERNIGHT INTO FRIDAY MORNING. SHOWERS WITH SOME ISOLATED EMBEDDED THUNDER WILL CONTINUE UNTIL SATURDAY MORNING AS THE SYSTEM PUSHES EAST. AS RIDGING DEVELOPS OVER THE AREA...NORTH/CENTRAL TX SHOULD REMAIN COOL AND DRY THROUGH EARLY NEXT WEEK. 84 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 33 42 27 35 32 / 5 5 5 10 20 WACO, TX 34 45 29 38 32 / 5 5 5 10 30 PARIS, TX 30 43 25 40 31 / 5 5 5 10 10 DENTON, TX 30 41 23 34 29 / 5 5 5 10 20 MCKINNEY, TX 29 42 24 35 31 / 5 5 5 10 20 DALLAS, TX 34 43 28 35 33 / 5 5 5 10 20 TERRELL, TX 32 44 28 37 33 / 5 5 5 10 20 CORSICANA, TX 36 45 29 39 34 / 5 5 5 10 30 TEMPLE, TX 35 46 29 38 32 / 5 5 5 10 30 MINERAL WELLS, TX 29 38 22 33 28 / 5 10 10 20 20 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
340 PM CST SUN DEC 28 2014 .DISCUSSION... TODAY/S PERSISTENT SHOWER ACTIVITY HAS NOW STARTED TO CLEAR THE WESTERNMOST COUNTIES AS OF 3 PM /GENERALLY AREAS WEST OF THE BRAZOS RIVER/. THIS ACTIVITY WILL CONTINUE TO PRODUCE LIGHT RAINFALL TOTALS INTO THE EVENING HOURS AS IT TRANSLATES EAST AHEAD OF A COMPACT SHORTWAVE TROUGH MOVING ACROSS THE STATE. THE EDGE OF THE CLOUD DECK ASSOCIATED WITH THE RAIN LAGS BEHIND THE END OF THE RAINFALL AND IS NOT ANTICIPATED TO REACH SOUTHEAST TEXAS UNTIL LATER THIS EVENING. WHILE IT SEEMS RELATIVELY BENIGN...THE TIMING/EVOLUTION OF THIS CLOUD DECK WILL ACTUALLY PLAY A VERY IMPORTANT ROLE IN THE SHORT TERM FORECAST IN TERMS OF OVERNIGHT LOW TEMPERATURES AND THE POTENTIAL FOR FOG DEVELOPMENT. SIMPLE EXTRAPOLATION OF THE WESTERN EDGE OF THE CLOUD DECK FROM VISIBLE SATELLITE SHOWS THIS CLEARING REACHING THE WESTERN EDGE OF THE FORECAST AREA AROUND 00-02Z...AND MODEL GUIDANCE SHOWS THE CLEARING LINE PUSHING EAST THROUGH THE OVERNIGHT HOURS. THERE/S STILL SOME UNCERTAINTY ON HOW FAR EAST THE LINE WILL PUSH THOUGH...WITH GENERAL CONSENSUS SHOWING IT REACHING NEAR THE I-45 CORRDIOR EARLY MONDAY MORNING. AS THIS LINE PUSHES EAST...THE WESTERN AREAS WILL BE ALLOWED THE OPPORTUNITY TO RADIATIONALLY COOL ENOUGH TO EXPERIENCE A LIGHT/BRIEF FREEZE. IF THE CLOUDS DO NOT CLEAR AS QUICKLY /OR CLEAR FASTER/...OVERNIGHT LOW TEMPERATURES WILL BE AFFECTED WITH THE ADDITION /OR LOSS/ OF A CLOUD BLANKET. ADDITIONALLY...RELATIVELY LIGHT WINDS OVERNIGHT WILL KEEP MIXING TO A MINIMUM...RAISING THE POTENTIAL FOR SOME FOG DEVELOPMENT /ESPECIALLY IN AREAS THAT CLEAR/. LATEST RAP AND HRRR VISIBILITY PROGS OFFER CONSIDERABLE DISAGREEMENT ON WHETHER OR NOT FOG WILL DEVELOP. FOR NOW...WILL LEAVE PATCHY FOG MENTION OUT OF THE FORECAST BUT ISOLATED DEVELOPMENT IS STILL POSSIBLE. THE GENERAL UPPER AIR PATTERN THIS AFTERNOON HAS CONSISTED OF A LONGWAVE TROUGH DRAPED ACROSS THE CONUS...WITH SEVERAL DISTURBANCES ROTATING THROUGH THIS FEATURE. THE MOST NOTICEABLE FOR US HAS BEEN THE ONE RESPONSIBLE FOR TODAY/S RAIN. TWO DISTURBANCES FARTHER UPSTREAM /ONE OVER THE NORTHWESTERN CONUS AND ANOTHER OVER THE NORTHWEST TERRITORIES OF CANADA/ WILL IMPACT THE REGION/S WEATHER LATER IN THE WEEK. BEHIND TODAY/S SHORTWAVE... A GENERALLY ZONAL FLOW BECOMES ESTABLISHED ACROSS THE SOUTHERN CONUS. DESPITE THE PRESENCE OF AT LEAST PARTLY CLOUDY SKIES MONDAY... ENOUGH INSOLATION WILL REACH THE SURFACE TO ALLOW TEMPERATURES TO REBOUND INTO THE MID TO UPPER 50S. MONDAY/S WARM UP WILL BE SHORT-LIVED AS THE DISTURBANCE OVER THE NW CONUS CROSSES THE CENTRAL PLAINS WITH AN ARCTIC AIRMASS OOZING THE AREA TUESDAY THROUGH THURSDAY. NORTHERLY WINDS WILL INCREASE AS THE LEADING EDGE OF THIS ARCTIC AIR MOVES INTO THE AREA ON TUESDAY...AND TEMPERATURES STILL REMAIN A CONCERN WITH THIS SYSTEM. THE EXTENT OF THE MODIFICATION OF THE AIRMASS /FROM EITHER DIABATIC OR ADIABATIC PROCESSES/ IS STILL NOT ENTIRELY CLEAR...BUT WILL CONTINUE THE TREND OF GOING BELOW MODEL GUIDANCE AS THE EVENT EVOLVES. THIS LEAVES THE OUTLOOK FOR MID-WEEK CHILLY WITH HIGHS WEDNESDAY AND THURSDAY IN THE MID 40S TO NEAR 50. THE FORMERLY CANADIAN SHORTWAVE DROPS TOWARDS THE FOUR CORNERS REGION BY WEDNESDAY...ESTABLISHING A SOUTHWEST FLOW ALOFT /WHICH ALLOWS FOR SOME MID LEVEL MOISTURE RETURN INTO THE REGION/ AND INCREASING ISENTROPIC LIFT. RAIN CHANCES WILL NOT BEGIN TO INCREASE UNTIL THURSDAY WITH THIS LIFT...AS FORECAST SOUNDINGS SHOW RELATIVELY DRY LOWER LEVELS WILL PREVENT ANY PRECIPITATION THAT DEVELOPS FROM REACHING THE GROUND. GUIDANCE INDICATES A SUBTLE SHORTWAVE TROUGH MAY TRANSLATE NORTHWEST OF THE AREA LATE THURSDAY...POSSIBLY INCREASING RAIN CHANCES FOR THE NORTHWEST ZONES...BUT THE REGION MAY BE TOO FAR AWAY FROM THIS EXTRA SOURCE OF LIFT TO ENHANCE OUR CHANCES. BY FRIDAY...THUNDERSTORM CHANCES ARE ON THE INCREASE AS A COASTAL TROUGH AND ASSOCIATED WARM FRONT DEVELOP ALONG THE TEXAS COAST. STILL SOME QUESTIONS REGARDING EXTENT OF GULF MOISTURE RETURN...BUT ENOUGH INSTABILITY APPEARS PRESENT AT THIS POINT TO CONTINUE THUNDERSTORM CHANCES FRIDAY INTO FRIDAY NIGHT. AS THE CANADIAN SHORTWAVE CROSSES TEXAS...ANOTHER COLD FRONT WILL REACH THE AREA AND END RAIN CHANCES HEADING INTO LATE SATURDAY. HUFFMAN && .MARINE... BOTH NORTH WINDS AND SEAS WILL DECREASE TONIGHT AND MONDAY AS HIGH PRESSURE MOVES OVER THE AREA. THE NEXT COLD FRONT MONDAY NIGHT THROUGH TUESDAY MORNING WILL BRING STRENGTHENING NORTHEAST WINDS ACROSS THE WATERS. CAUTION FLAGS ARE LIKELY...AND ADVISORIES MIGHT BE NEEDED TUESDAY THROUGH THURSDAY NIGHT. SOUTH WINDS ARE EXPECTED TO RETURN ON FRIDAY AND FRIDAY NIGHT AS A WARM FRONT MOVES INLAND. LIGHT TO MODERATE NORTH WINDS COME BACK OVER THE WEEKEND. 42 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 42 33 58 38 51 / 60 10 0 0 10 HOUSTON (IAH) 44 36 59 42 57 / 70 10 0 0 10 GALVESTON (GLS) 49 43 57 48 56 / 70 20 0 0 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
946 AM CST SUN DEC 28 2014 .UPDATE... A MINOR UPDATE TO ADJUST FOR CURRENT TRENDS...AS A SHORTWAVE TROUGH PASSES EAST OVER THE REGION TODAY. ISENTROPIC ASCENT CONTINUES AHEAD OF THE APPROACHING TROUGH ACROSS CENTRAL TEXAS THIS MORNING. SCATTERED AREAS OF VERY LIGHT...OCCASIONALLY MIXED WITH SOME VERY LIGHT SLEET OR SNOW CONTINUES AS COLUMN COOLING AND SATURATION OCCUR WITH THE LIFT AND STEEPENING MID LEVEL LAPSE RATES MOVING ACROSS THE AREA. SURFACE TEMPERATURES CONTINUE TO REMAIN IN THE MID-UPPER 30S...SO WE DO NOT EXPECT ANY IMPACTS ON AREA ROADS FOR TRAVELERS...THOUGH BRIDGE AND OVERPASSES SHOULD STILL BE TAKEN SLOWLY UNTIL THE VERY LIGHT PRECIPITATION MIXTURE ENDS. LIGHT RAIN WILL CONTINUE INTO THE EARLY AFTERNOON HOURS ACROSS OUR SOUTHEAST COUNTIES WITH SHORTWAVE PROGRESSING EAST ACROSS THIS AREA. ENVIRONMENTAL SOUNDINGS WILL BE LITTLE WARMER ALOFT ACROSS THESE AREAS AND EXPECT MOSTLY LIGHT RAIN. SURFACE TEMPERATURES WILL WARM INTO THE 40S. HOWEVER...AS THE CORE INCREASING MID LEVEL INSTABILITY ROTATES ACROSS A FEW SLEET PELLET SHOWERS CANNOT BE RULED OUT EVEN THIS AFTERNOON. CLEARING ACROSS THE NORTHWEST HALF OF THE AREA SHOULD HELP HIGHS WARM TO AROUND 50 OR IN THE LOWER 50S WITH THE HELP OF INCREASING INSOLATION. 05/ && .AVIATION... /ISSUED 600 AM CST SUN DEC 28 2014/ VFR CONDITIONS ARE EXPECTED THROUGH MONDAY MORNING. BROKEN TO OVERCAST MID CLOUDS THIS MORNING WILL SCATTER FROM WEST TO EAST THIS AFTERNOON ONCE LARGE SCALE SUBSIDENCE INCREASES BEHIND A PASSING UPPER TROUGH. SOME BRIEF LIGHT RAIN IS POSSIBLE IN WACO THIS MORNING BUT IT SHOULD HAVE NO SIGNIFICANT IMPACT TO AIRCRAFT OPERATIONS. A NORTH WIND WILL PREVAIL TODAY AT SPEEDS LESS THAN 12 KNOTS. THE WIND WILL BECOME LIGHT SOUTHEAST BY SUNSET AND REMAIN FROM THE SOUTH/SOUTHEAST OVERNIGHT. 79 && .PREV UPDATE... .UPDATE... HAVE INCREASED POPS ACROSS OUR SOUTHWEST COUNTIES WHERE LIGHT RAIN MAY BE OBSERVED SOON. ALSO EXPANDED POPS FURTHER NORTH BASED ON THE LATEST RADAR TRENDS AND TRACKS OF ECHOES. LIGHT RAIN IS CURRENTLY BE REPORTED ALONG AND SOUTH OF A LINE FROM LAMPASAS TO MEXIA TO ATHENS. NORTH OF THIS LINE THERE IS STILL DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE THAT NEEDS TO BE OVERCOME/SATURATED BEFORE ANY PRECIPITATION REACHES THE GROUND. EXPANDED THE RAIN MENTION AS FAR NORTH AS A CISCO TO DFW TO EMORY LINE THIS MORNING. WILL ALSO INCLUDE A MENTION FOR LIGHT SLEET MIXING WITH THE RAIN IN AN AREA WEST OF A CLEBURNE TO TEMPLE LINE. SOME LIGHT SLEET HAS BEEN REPORTED JUST SOUTHWEST OF THE AREA AND THE LATEST RAP RUN INDICATES TEMPERATURES MAY BE COLD ENOUGH FOR A LITTLE BIT OF SLEET TO MIX WITH THE RAIN FOR A FEW HOURS THIS MORNING. NO ACCUMULATIONS OR IMPACTS ARE EXPECTED FROM THE SLEET. 82/JLD && .PREV DISCUSSION... /ISSUED 404 AM CST SUN DEC 28 2014/ AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES MOVING EAST AND WILL PROVIDE LIFT FOR ADDITIONAL RAIN ACROSS OUR SOUTH AND SOUTHEASTERN COUNTIES TODAY. THE RADAR ACROSS CENTRAL AND SOUTHEAST TEXAS HAS LOOKED ACTIVE ALL NIGHT BUT A LEVEL OF DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE HAS PREVENTED MUCH PRECIPITATION FROM REACHING THE GROUND SO FAR. EVEN THOUGH THE RADAR HAS GIVEN THE APPEARANCE THAT IT HAS BEEN RAINING ALMOST ALL NIGHT SOUTH OF A GATESVILLE TO ATHENS LINE...NONE OF THE AUTOMATED WEATHER STATIONS HAVE REPORTED ANY RAIN UNTIL AN HOUR AGO. HEARNE /KLHB/ FINALLY REPORTED RAIN ON THEIR 3 AM HOURLY OB INDICATING THAT THE LOWER LEVELS OF THE ATMOSPHERE ARE FINALLY STARTING TO SATURATE DOWN. EXPECT OTHER SITES IN THAT AREA TO BEGIN REPORTING LIGHT RAIN BEFORE SUNRISE. LIGHT TO MODERATE RAIN WILL OCCUR SOUTHEAST OF A LAMPASAS TO MIDLOTHIAN TO SULPHUR SPRINGS LINE TODAY WITH THE BEST RAIN CHANCES IN THE MORNING HOURS. RAINFALL AMOUNTS WILL BE LIGHT AND THE RAIN IS EXPECTED TO END THIS AFTERNOON. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION WILL REMAIN LIQUID WITH NO FROZEN PRECIPITATION MIXING...EVEN AS THE UPPER LEVEL LOW APPROACHES LATER TODAY. HOWEVER...WILL BE MONITORING FOR ANY CHANGES TO THE LOW LEVEL TEMPERATURE PROFILE FOR POSSIBLY SOME SLEET MIXING IN. CLOUDY SKIES THIS MORNING WILL CLEAR FROM WEST TO EAST THIS AFTERNOON AS THE UPPER LEVEL TROUGH MOVES OVER THE REGION. THIS WILL ALLOW FOR OUR WESTERN COUNTIES TO WARM INTO THE UPPER 40S THIS AFTERNOON BUT OUR EASTERN COUNTIES CAN EXPECT A COOL DAY WITH AFTERNOON TEMPS IN THE LOWER 40S DUE TO THE PERSISTENT CLOUD COVER. WITH THE SKIES CLEARING TONIGHT AND WINDS BECOMING LIGHT...TEMPERATURES ARE EXPECTED TO FALL INTO THE UPPER 20S AND LOWER 30S ACROSS THE REGION. THE RETURN OF SOME HIGH CLOUD COVER ON MONDAY WILL KEEP TEMPERATURES IN THE 50S AND LOWER 60S. OVERALL...THE FORECAST FOR THE TUESDAY THROUGH FRIDAY TIME FRAME HAS NOT CHANGED MUCH BUT DID MAKE SOME ADJUSTMENTS TO THE WINTER WEATHER PRECIPITATION DURING THIS TIME PERIOD. THE ARCTIC FRONT IS STILL EXPECTED TO ARRIVE MONDAY NIGHT/TUESDAY MORNING. IT WILL STEADILY SPREAD ACROSS THE REGION WITH WINDS OF 10-15 MPH BEHIND IT. THE AIR MASS WILL BE MODIFIED A LITTLE DURING THE DAY ON TUESDAY DUE TO SOUTH AND EAST 850 MB WINDS ABOVE THE FRONT AND WEST WINDS ABOVE 850 MB. HOWEVER...TUESDAY THROUGH WEDNESDAY NIGHT WILL STILL BE A RATHER COLD PERIOD WITH HIGHS ONLY IN THE 30S AND 40S AND LOWS IN THE 20S AND 30S. WE CONTINUE TO MAINTAIN A DRY FORECAST MONDAY NIGHT THROUGH TUESDAY NIGHT AS THERE IS A LACK OF LIFT ACROSS THE REGION. WE WILL BE IN NEAR ZONAL FLOW ALOFT AS A STRONG UPPER LEVEL LOW MOVES DOWN THE WEST COAST BUT IT WILL STILL BE TOO FAR WEST AT THAT TIME TO SPREAD ANY LARGE SCALE LIFT OVER OUR AREA. ISENTROPIC CHARTS ALSO INDICATE A LACK OF LIFT IN OUR AREA DURING THIS PERIOD. WE START TO NOTICE SOME WEAK ISENTROPIC LIFT BETWEEN THE 800-700 MB LAYER BEGINNING WEDNESDAY IN OUR SOUTHERN ZONES. ANALYZING THIS LAYER IN THE FORECASTED SOUNDINGS...WE SEE MOISTURE IN THE LAYER WHERE THE LIFT IS OCCURRING...BUT THE LAYER BELOW 800 MB...AND IN PARTICULAR BELOW 900 MB...IS DRY AND WOULD LIKELY EVAPORATE ANY PRECIPITATION BEFORE IT REACHES THE GROUND. SO THE CHALLENGE NOW IS WILL THE LOWER LAYER SATURATE ENOUGH FROM TOP-DOWN PROCESSES TO ALLOW ANY PRECIPITATION TO REACH THE GROUND? THIS APPEARS TO BE A LOW CHANCE AS THE LIFT DOES NOT LOOK STRONG ENOUGH TO GENERATE ENOUGH PRECIPITATION TO SATURATE THE LAYER ALL THE WAY DOWN TO THE SURFACE. THE RADAR MAY SHOW A LOT OF ECHOES ON WEDNESDAY...BUT DO NOT ANTICIPATE PRECIPITATION WILL REACH THE GROUND. HOWEVER...WILL LEAVE 20 POPS FOR DRIZZLE SOUTHWEST OF A CISCO TO HILLSBORO TO FREESTONE LINE IN CASE SOME LIGHT RAIN DOES REACH THE GROUND. DEPENDING ON THE TIME AND TEMPERATURES...THERE COULD BE A BRIEF PERIOD OF FREEZING DRIZZLE WEST OF I-35. OUR MAIN TIME FRAME OF CONCERN FOR FROZEN PRECIPITATION IS WEDNESDAY NIGHT/EARLY THURSDAY MORNING AS THE ISENTROPIC LIFT CONTINUES BUT ALSO SPREADS NORTH OVER MORE OF THE REGION AND STRENGTHENS. THE MODELS ARE NOT OUTPUTTING ANY QPF DURING THIS 12 HOUR PERIOD FROM 6 PM WEDNESDAY TO 6 AM THURSDAY BECAUSE THEY CONTINUE TO KEEP THE LOWER LEVELS OF THE ATMOSPHERE DRY /AS INDICATED ON THE FORECASTED SOUNDINGS/. THE LOWER LEVELS OF THE ATMOSPHERE WILL EVENTUALLY SATURATE DOWN AS THE ISENTROPIC LIFT CONTINUES BUT THE QUESTION AND CHALLENGE IS WHEN WILL THAT OCCUR. THE DETERMINISTIC MODELS SUGGEST THIS WILL NOT HAPPEN UNTIL AFTER 6 AM THURSDAY WHEN TEMPERATURES ARE ALREADY ABOVE FREEZING /TEMPERATURES ARE EXPECTED TO EVENTUALLY RISE WEDNESDAY NIGHT UNDER THE INFLUENCE OF WARM AIR ADVECTION DUE TO THE ISENTROPIC LIFT/...BUT IT IS POSSIBLE THIS COULD OCCUR DURING THE NIGHT WEDNESDAY. SO WILL KEEP A LOW CHANCE FOR LIGHT RAIN AND/OR LIGHT FREEZING RAIN ALONG AND SOUTH OF A LINE FROM BRECKENRIDGE TO DFW TO EMORY. THE FREEZING RAIN WILL BE MENTIONED ALONG AND WEST OF A LINE FROM WEATHERFORD TO LAMPASAS. IF FREEZING RAIN OCCURS DURING THE TIME FROM 6 PM WEDNESDAY TO 6 AM THURSDAY...WE DO NOT EXPECT SIGNIFICANT IMPACTS AS TEMPERATURES WILL BE WARMING OVERNIGHT AND THE CHANGEOVER TO LIQUID RAIN SHOULD MELT ANY MINIMAL ICE ACCUMULATIONS. HOWEVER...IF TEMPERATURES THAT NIGHT ARE COLDER THAN THEY ARE CURRENTLY FORECAST TO BE AND ARE REALIZED IN THE UPPER 20S...THERE COULD BE SOME MINOR ACCUMULATIONS AND POSSIBLY MINOR IMPACTS FOR A SHORT PERIOD OF TIME DURING THE NIGHT. IF TEMPERATURES WERE TO FALL INTO THE UPPER 20S...THE MOST LIKELY LOCATION FOR THIS TO HAPPEN WOULD BE WEST ON I-35. RAIN CHANCES ARE STILL LOOKING DECENT ACROSS THE REGION ON THURSDAY AND FRIDAY AS THE UPPER LEVEL LOW ALONG THE WEST COAST FINALLY MOVES INTO THE SOUTHERN PLAINS. AGAIN...THIS IS EXPECTED TO REMAIN AS LIQUID RAIN. THERE ARE SOME DIFFERENCES WITHIN THE MODELS REGARDING THE BEST TIMING FOR RAIN CHANCES ON THESE DAYS AND WE WILL HOPEFULLY BE ABLE TO REFINE THEM OVER THE NEXT FEW DAYS. ONE INTERESTING FEATURE TO WATCH WILL BE THE POSSIBILITY OF A SHORTWAVE AHEAD OF THE UPPER LOW ON THURSDAY. THE GFS DEVELOPS THIS SHORTWAVE GIVING US BETTER RAIN CHANCES ON THURSDAY AS A RESULT. THE ECMWF DOES NOT HAVE THIS SHORTWAVE AND THEREFORE HAS BETTER RAIN CHANCES ON FRIDAY AS THE UPPER LEVEL LOW MOVES OVER THE AREA. SOME THUNDER WILL BE POSSIBLE THURSDAY NIGHT AND FRIDAY. ANOTHER FRONT IS EXPECTED BEHIND THIS SYSTEM ON SATURDAY AND IT IS STARTING TO LOOK LIKE THE AIR BEHIND THIS FRONT COULD BE PRETTY COLD AS WELL. 82/JLD && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 46 32 56 34 43 / 10 0 5 5 5 WACO, TX 44 27 59 33 46 / 30 5 5 5 5 PARIS, TX 43 30 51 33 44 / 10 0 5 5 5 DENTON, TX 46 27 56 28 42 / 5 0 5 5 5 MCKINNEY, TX 45 26 54 28 43 / 10 0 5 5 5 DALLAS, TX 47 32 56 35 44 / 10 0 5 5 5 TERRELL, TX 43 29 55 34 45 / 10 0 5 5 5 CORSICANA, TX 43 31 56 35 46 / 30 5 5 5 5 TEMPLE, TX 43 27 61 34 46 / 40 5 5 5 5 MINERAL WELLS, TX 47 29 57 28 40 / 5 0 5 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 79/05
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
600 AM CST SUN DEC 28 2014 .AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH MONDAY MORNING. BROKEN TO OVERCAST MID CLOUDS THIS MORNING WILL SCATTER FROM WEST TO EAST THIS AFTERNOON ONCE LARGE SCALE SUBSIDENCE INCREASES BEHIND A PASSING UPPER TROUGH. SOME BRIEF LIGHT RAIN IS POSSIBLE IN WACO THIS MORNING BUT IT SHOULD HAVE NO SIGNIFICANT IMPACT TO AIRCRAFT OPERATIONS. A NORTH WIND WILL PREVAIL TODAY AT SPEEDS LESS THAN 12 KNOTS. THE WIND WILL BECOME LIGHT SOUTHEAST BY SUNSET AND REMAIN FROM THE SOUTH/SOUTHEAST OVERNIGHT. 79 && .UPDATE... HAVE INCREASED POPS ACROSS OUR SOUTHWEST COUNTIES WHERE LIGHT RAIN MAY BE OBSERVED SOON. ALSO EXPANDED POPS FURTHER NORTH BASED ON THE LATEST RADAR TRENDS AND TRACKS OF ECHOES. LIGHT RAIN IS CURRENTLY BE REPORTED ALONG AND SOUTH OF A LINE FROM LAMPASAS TO MEXIA TO ATHENS. NORTH OF THIS LINE THERE IS STILL DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE THAT NEEDS TO BE OVERCOME/SATURATED BEFORE ANY PRECIPITATION REACHES THE GROUND. EXPANDED THE RAIN MENTION AS FAR NORTH AS A CISCO TO DFW TO EMORY LINE THIS MORNING. WILL ALSO INCLUDE A MENTION FOR LIGHT SLEET MIXING WITH THE RAIN IN AN AREA WEST OF A CLEBURNE TO TEMPLE LINE. SOME LIGHT SLEET HAS BEEN REPORTED JUST SOUTHWEST OF THE AREA AND THE LATEST RAP RUN INDICATES TEMPERATURES MAY BE COLD ENOUGH FOR A LITTLE BIT OF SLEET TO MIX WITH THE RAIN FOR A FEW HOURS THIS MORNING. NO ACCUMULATIONS OR IMPACTS ARE EXPECTED FROM THE SLEET. 82/JLD && .PREV DISCUSSION... /ISSUED 404 AM CST SUN DEC 28 2014/ AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES MOVING EAST AND WILL PROVIDE LIFT FOR ADDITIONAL RAIN ACROSS OUR SOUTH AND SOUTHEASTERN COUNTIES TODAY. THE RADAR ACROSS CENTRAL AND SOUTHEAST TEXAS HAS LOOKED ACTIVE ALL NIGHT BUT A LEVEL OF DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE HAS PREVENTED MUCH PRECIPITATION FROM REACHING THE GROUND SO FAR. EVEN THOUGH THE RADAR HAS GIVEN THE APPEARANCE THAT IT HAS BEEN RAINING ALMOST ALL NIGHT SOUTH OF A GATESVILLE TO ATHENS LINE...NONE OF THE AUTOMATED WEATHER STATIONS HAVE REPORTED ANY RAIN UNTIL AN HOUR AGO. HEARNE /KLHB/ FINALLY REPORTED RAIN ON THEIR 3 AM HOURLY OB INDICATING THAT THE LOWER LEVELS OF THE ATMOSPHERE ARE FINALLY STARTING TO SATURATE DOWN. EXPECT OTHER SITES IN THAT AREA TO BEGIN REPORTING LIGHT RAIN BEFORE SUNRISE. LIGHT TO MODERATE RAIN WILL OCCUR SOUTHEAST OF A LAMPASAS TO MIDLOTHIAN TO SULPHUR SPRINGS LINE TODAY WITH THE BEST RAIN CHANCES IN THE MORNING HOURS. RAINFALL AMOUNTS WILL BE LIGHT AND THE RAIN IS EXPECTED TO END THIS AFTERNOON. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION WILL REMAIN LIQUID WITH NO FROZEN PRECIPITATION MIXING...EVEN AS THE UPPER LEVEL LOW APPROACHES LATER TODAY. HOWEVER...WILL BE MONITORING FOR ANY CHANGES TO THE LOW LEVEL TEMPERATURE PROFILE FOR POSSIBLY SOME SLEET MIXING IN. CLOUDY SKIES THIS MORNING WILL CLEAR FROM WEST TO EAST THIS AFTERNOON AS THE UPPER LEVEL TROUGH MOVES OVER THE REGION. THIS WILL ALLOW FOR OUR WESTERN COUNTIES TO WARM INTO THE UPPER 40S THIS AFTERNOON BUT OUR EASTERN COUNTIES CAN EXPECT A COOL DAY WITH AFTERNOON TEMPS IN THE LOWER 40S DUE TO THE PERSISTENT CLOUD COVER. WITH THE SKIES CLEARING TONIGHT AND WINDS BECOMING LIGHT...TEMPERATURES ARE EXPECTED TO FALL INTO THE UPPER 20S AND LOWER 30S ACROSS THE REGION. THE RETURN OF SOME HIGH CLOUD COVER ON MONDAY WILL KEEP TEMPERATURES IN THE 50S AND LOWER 60S. OVERALL...THE FORECAST FOR THE TUESDAY THROUGH FRIDAY TIME FRAME HAS NOT CHANGED MUCH BUT DID MAKE SOME ADJUSTMENTS TO THE WINTER WEATHER PRECIPITATION DURING THIS TIME PERIOD. THE ARCTIC FRONT IS STILL EXPECTED TO ARRIVE MONDAY NIGHT/TUESDAY MORNING. IT WILL STEADILY SPREAD ACROSS THE REGION WITH WINDS OF 10-15 MPH BEHIND IT. THE AIR MASS WILL BE MODIFIED A LITTLE DURING THE DAY ON TUESDAY DUE TO SOUTH AND EAST 850 MB WINDS ABOVE THE FRONT AND WEST WINDS ABOVE 850 MB. HOWEVER...TUESDAY THROUGH WEDNESDAY NIGHT WILL STILL BE A RATHER COLD PERIOD WITH HIGHS ONLY IN THE 30S AND 40S AND LOWS IN THE 20S AND 30S. WE CONTINUE TO MAINTAIN A DRY FORECAST MONDAY NIGHT THROUGH TUESDAY NIGHT AS THERE IS A LACK OF LIFT ACROSS THE REGION. WE WILL BE IN NEAR ZONAL FLOW ALOFT AS A STRONG UPPER LEVEL LOW MOVES DOWN THE WEST COAST BUT IT WILL STILL BE TOO FAR WEST AT THAT TIME TO SPREAD ANY LARGE SCALE LIFT OVER OUR AREA. ISENTROPIC CHARTS ALSO INDICATE A LACK OF LIFT IN OUR AREA DURING THIS PERIOD. WE START TO NOTICE SOME WEAK ISENTROPIC LIFT BETWEEN THE 800-700 MB LAYER BEGINNING WEDNESDAY IN OUR SOUTHERN ZONES. ANALYZING THIS LAYER IN THE FORECASTED SOUNDINGS...WE SEE MOISTURE IN THE LAYER WHERE THE LIFT IS OCCURRING...BUT THE LAYER BELOW 800 MB...AND IN PARTICULAR BELOW 900 MB...IS DRY AND WOULD LIKELY EVAPORATE ANY PRECIPITATION BEFORE IT REACHES THE GROUND. SO THE CHALLENGE NOW IS WILL THE LOWER LAYER SATURATE ENOUGH FROM TOP-DOWN PROCESSES TO ALLOW ANY PRECIPITATION TO REACH THE GROUND? THIS APPEARS TO BE A LOW CHANCE AS THE LIFT DOES NOT LOOK STRONG ENOUGH TO GENERATE ENOUGH PRECIPITATION TO SATURATE THE LAYER ALL THE WAY DOWN TO THE SURFACE. THE RADAR MAY SHOW A LOT OF ECHOES ON WEDNESDAY...BUT DO NOT ANTICIPATE PRECIPITATION WILL REACH THE GROUND. HOWEVER...WILL LEAVE 20 POPS FOR DRIZZLE SOUTHWEST OF A CISCO TO HILLSBORO TO FREESTONE LINE IN CASE SOME LIGHT RAIN DOES REACH THE GROUND. DEPENDING ON THE TIME AND TEMPERATURES...THERE COULD BE A BRIEF PERIOD OF FREEZING DRIZZLE WEST OF I-35. OUR MAIN TIME FRAME OF CONCERN FOR FROZEN PRECIPITATION IS WEDNESDAY NIGHT/EARLY THURSDAY MORNING AS THE ISENTROPIC LIFT CONTINUES BUT ALSO SPREADS NORTH OVER MORE OF THE REGION AND STRENGTHENS. THE MODELS ARE NOT OUTPUTTING ANY QPF DURING THIS 12 HOUR PERIOD FROM 6 PM WEDNESDAY TO 6 AM THURSDAY BECAUSE THEY CONTINUE TO KEEP THE LOWER LEVELS OF THE ATMOSPHERE DRY /AS INDICATED ON THE FORECASTED SOUNDINGS/. THE LOWER LEVELS OF THE ATMOSPHERE WILL EVENTUALLY SATURATE DOWN AS THE ISENTROPIC LIFT CONTINUES BUT THE QUESTION AND CHALLENGE IS WHEN WILL THAT OCCUR. THE DETERMINISTIC MODELS SUGGEST THIS WILL NOT HAPPEN UNTIL AFTER 6 AM THURSDAY WHEN TEMPERATURES ARE ALREADY ABOVE FREEZING /TEMPERATURES ARE EXPECTED TO EVENTUALLY RISE WEDNESDAY NIGHT UNDER THE INFLUENCE OF WARM AIR ADVECTION DUE TO THE ISENTROPIC LIFT/...BUT IT IS POSSIBLE THIS COULD OCCUR DURING THE NIGHT WEDNESDAY. SO WILL KEEP A LOW CHANCE FOR LIGHT RAIN AND/OR LIGHT FREEZING RAIN ALONG AND SOUTH OF A LINE FROM BRECKENRIDGE TO DFW TO EMORY. THE FREEZING RAIN WILL BE MENTIONED ALONG AND WEST OF A LINE FROM WEATHERFORD TO LAMPASAS. IF FREEZING RAIN OCCURS DURING THE TIME FROM 6 PM WEDNESDAY TO 6 AM THURSDAY...WE DO NOT EXPECT SIGNIFICANT IMPACTS AS TEMPERATURES WILL BE WARMING OVERNIGHT AND THE CHANGEOVER TO LIQUID RAIN SHOULD MELT ANY MINIMAL ICE ACCUMULATIONS. HOWEVER...IF TEMPERATURES THAT NIGHT ARE COLDER THAN THEY ARE CURRENTLY FORECAST TO BE AND ARE REALIZED IN THE UPPER 20S...THERE COULD BE SOME MINOR ACCUMULATIONS AND POSSIBLY MINOR IMPACTS FOR A SHORT PERIOD OF TIME DURING THE NIGHT. IF TEMPERATURES WERE TO FALL INTO THE UPPER 20S...THE MOST LIKELY LOCATION FOR THIS TO HAPPEN WOULD BE WEST ON I-35. RAIN CHANCES ARE STILL LOOKING DECENT ACROSS THE REGION ON THURSDAY AND FRIDAY AS THE UPPER LEVEL LOW ALONG THE WEST COAST FINALLY MOVES INTO THE SOUTHERN PLAINS. AGAIN...THIS IS EXPECTED TO REMAIN AS LIQUID RAIN. THERE ARE SOME DIFFERENCES WITHIN THE MODELS REGARDING THE BEST TIMING FOR RAIN CHANCES ON THESE DAYS AND WE WILL HOPEFULLY BE ABLE TO REFINE THEM OVER THE NEXT FEW DAYS. ONE INTERESTING FEATURE TO WATCH WILL BE THE POSSIBILITY OF A SHORTWAVE AHEAD OF THE UPPER LOW ON THURSDAY. THE GFS DEVELOPS THIS SHORTWAVE GIVING US BETTER RAIN CHANCES ON THURSDAY AS A RESULT. THE ECMWF DOES NOT HAVE THIS SHORTWAVE AND THEREFORE HAS BETTER RAIN CHANCES ON FRIDAY AS THE UPPER LEVEL LOW MOVES OVER THE AREA. SOME THUNDER WILL BE POSSIBLE THURSDAY NIGHT AND FRIDAY. ANOTHER FRONT IS EXPECTED BEHIND THIS SYSTEM ON SATURDAY AND IT IS STARTING TO LOOK LIKE THE AIR BEHIND THIS FRONT COULD BE PRETTY COLD AS WELL. 82/JLD && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 46 32 56 34 43 / 10 0 5 5 5 WACO, TX 44 27 59 33 46 / 40 5 5 5 5 PARIS, TX 43 30 51 33 44 / 10 0 5 5 5 DENTON, TX 46 27 56 28 42 / 10 0 5 5 5 MCKINNEY, TX 45 26 54 28 43 / 10 0 5 5 5 DALLAS, TX 47 32 56 35 44 / 20 0 5 5 5 TERRELL, TX 43 29 55 34 45 / 20 0 5 5 5 CORSICANA, TX 43 31 56 35 46 / 40 5 5 5 5 TEMPLE, TX 43 27 61 34 46 / 50 5 5 5 5 MINERAL WELLS, TX 47 29 57 28 40 / 10 0 5 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 79/82
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
537 AM CST SUN DEC 28 2014 .UPDATE... HAVE INCREASED POPS ACROSS OUR SOUTHWEST COUNTIES WHERE LIGHT RAIN MAY BE OBSERVED SOON. ALSO EXPANDED POPS FURTHER NORTH BASED ON THE LATEST RADAR TRENDS AND TRACKS OF ECHOES. LIGHT RAIN IS CURRENTLY BE REPORTED ALONG AND SOUTH OF A LINE FROM LAMPASAS TO MEXIA TO ATHENS. NORTH OF THIS LINE THERE IS STILL DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE THAT NEEDS TO BE OVERCOME/SATURATED BEFORE ANY PRECIPITATION REACHES THE GROUND. EXPANDED THE RAIN MENTION AS FAR NORTH AS A CISCO TO DFW TO EMORY LINE THIS MORNING. WILL ALSO INCLUDE A MENTION FOR LIGHT SLEET MIXING WITH THE RAIN IN AN AREA WEST OF A CLEBURNE TO TEMPLE LINE. SOME LIGHT SLEET HAS BEEN REPORTED JUST SOUTHWEST OF THE AREA AND THE LATEST RAP RUN INDICATES TEMPERATURES MAY BE COLD ENOUGH FOR A LITTLE BIT OF SLEET TO MIX WITH THE RAIN FOR A FEW HOURS THIS MORNING. NO ACCUMULATIONS OR IMPACTS ARE EXPECTED FROM THE SLEET. 82/JLD && .AVIATION... /ISSUED 1204 AM CST SUN DEC 28 2014/ VFR WILL PREVAIL OVER THE METROPLEX THROUGH THE PERIOD WITH JUST MID-HIGH LEVEL CLOUD COVER. STRONG UPPER LEVEL SHORTWAVE WILL MOVE THROUGH THE REGION MIDDAY SUNDAY. AHEAD OF THIS SYSTEM...LOTS OF MOISTURE/LIFT WILL RESULT IN PRECIPITATION ORIGINATING AT AN UNUSUALLY HIGH LEVEL...NEAR 22000FT. THIS PRECIP WILL BE FALLING INTO DRY AIR BELOW IT...SO MOSTLY VIRGA IS EXPECTED IN THE METROPLEX. HOWEVER SOME SATURATION WILL OCCUR WHICH WILL BRING CIGS DOWN TO NEAR 10000FT BY SUNRISE. IF PRECIP INTENSITY IS GREATER THAN EXPECTED OVER THE METROPLEX...WET BULB COOLING WOULD RESULT IN THERMAL PROFILE FAVORABLE FOR SLEET OR SNOW. BUT THERE IS CURRENTLY NO MODEL SHOWING THIS MUCH PRECIPITATION AVAILABLE...WHICH WOULD BE REQUIRED TO BOTH COOL AND SATURATE BEFORE ANY NON-LIQUID PRECIP REACHES THE GROUND. WE WILL CONTINUE TO WATCH TRENDS TO MONITOR FOR THIS VERY REMOTE POSSIBILITY. FOR WACO...MVFR CIGS MAY CONTINUE FOR THE NEXT HOUR OR TWO BUT VFR CIGS NEAR 050 SHOULD PREVAIL. MORE LOW LEVEL SATURATION IS EXPECTED THERE...SO -RA IS IN THE TAF FROM 10Z TO 16Z. THE THERMAL PROFILE LOOKS TOO WARM FOR ANY POSSIBILITY OF WINTRY PRECIP AT WACO EVEN AFTER WET BULB COOLING. ANY RAIN WILL ALSO BE VERY LIGHT...AND THUS NO VSBY RESTRICTIONS ARE FORECAST. OTHERWISE CLOUDS WILL CLEAR EARLY-MID AFTERNOON WITH LIGHT NORTH WINDS TURNING TO THE SOUTH SUNDAY EVENING. TR.92 && .PREV DISCUSSION... /ISSUED 404 AM CST SUN DEC 28 2014/ AN UPPER LEVEL TROUGH TO OUR WEST CONTINUES MOVING EAST AND WILL PROVIDE LIFT FOR ADDITIONAL RAIN ACROSS OUR SOUTH AND SOUTHEASTERN COUNTIES TODAY. THE RADAR ACROSS CENTRAL AND SOUTHEAST TEXAS HAS LOOKED ACTIVE ALL NIGHT BUT A LEVEL OF DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE HAS PREVENTED MUCH PRECIPITATION FROM REACHING THE GROUND SO FAR. EVEN THOUGH THE RADAR HAS GIVEN THE APPEARANCE THAT IT HAS BEEN RAINING ALMOST ALL NIGHT SOUTH OF A GATESVILLE TO ATHENS LINE...NONE OF THE AUTOMATED WEATHER STATIONS HAVE REPORTED ANY RAIN UNTIL AN HOUR AGO. HEARNE /KLHB/ FINALLY REPORTED RAIN ON THEIR 3 AM HOURLY OB INDICATING THAT THE LOWER LEVELS OF THE ATMOSPHERE ARE FINALLY STARTING TO SATURATE DOWN. EXPECT OTHER SITES IN THAT AREA TO BEGIN REPORTING LIGHT RAIN BEFORE SUNRISE. LIGHT TO MODERATE RAIN WILL OCCUR SOUTHEAST OF A LAMPASAS TO MIDLOTHIAN TO SULPHUR SPRINGS LINE TODAY WITH THE BEST RAIN CHANCES IN THE MORNING HOURS. RAINFALL AMOUNTS WILL BE LIGHT AND THE RAIN IS EXPECTED TO END THIS AFTERNOON. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION WILL REMAIN LIQUID WITH NO FROZEN PRECIPITATION MIXING...EVEN AS THE UPPER LEVEL LOW APPROACHES LATER TODAY. HOWEVER...WILL BE MONITORING FOR ANY CHANGES TO THE LOW LEVEL TEMPERATURE PROFILE FOR POSSIBLY SOME SLEET MIXING IN. CLOUDY SKIES THIS MORNING WILL CLEAR FROM WEST TO EAST THIS AFTERNOON AS THE UPPER LEVEL TROUGH MOVES OVER THE REGION. THIS WILL ALLOW FOR OUR WESTERN COUNTIES TO WARM INTO THE UPPER 40S THIS AFTERNOON BUT OUR EASTERN COUNTIES CAN EXPECT A COOL DAY WITH AFTERNOON TEMPS IN THE LOWER 40S DUE TO THE PERSISTENT CLOUD COVER. WITH THE SKIES CLEARING TONIGHT AND WINDS BECOMING LIGHT...TEMPERATURES ARE EXPECTED TO FALL INTO THE UPPER 20S AND LOWER 30S ACROSS THE REGION. THE RETURN OF SOME HIGH CLOUD COVER ON MONDAY WILL KEEP TEMPERATURES IN THE 50S AND LOWER 60S. OVERALL...THE FORECAST FOR THE TUESDAY THROUGH FRIDAY TIME FRAME HAS NOT CHANGED MUCH BUT DID MAKE SOME ADJUSTMENTS TO THE WINTER WEATHER PRECIPITATION DURING THIS TIME PERIOD. THE ARCTIC FRONT IS STILL EXPECTED TO ARRIVE MONDAY NIGHT/TUESDAY MORNING. IT WILL STEADILY SPREAD ACROSS THE REGION WITH WINDS OF 10-15 MPH BEHIND IT. THE AIR MASS WILL BE MODIFIED A LITTLE DURING THE DAY ON TUESDAY DUE TO SOUTH AND EAST 850 MB WINDS ABOVE THE FRONT AND WEST WINDS ABOVE 850 MB. HOWEVER...TUESDAY THROUGH WEDNESDAY NIGHT WILL STILL BE A RATHER COLD PERIOD WITH HIGHS ONLY IN THE 30S AND 40S AND LOWS IN THE 20S AND 30S. WE CONTINUE TO MAINTAIN A DRY FORECAST MONDAY NIGHT THROUGH TUESDAY NIGHT AS THERE IS A LACK OF LIFT ACROSS THE REGION. WE WILL BE IN NEAR ZONAL FLOW ALOFT AS A STRONG UPPER LEVEL LOW MOVES DOWN THE WEST COAST BUT IT WILL STILL BE TOO FAR WEST AT THAT TIME TO SPREAD ANY LARGE SCALE LIFT OVER OUR AREA. ISENTROPIC CHARTS ALSO INDICATE A LACK OF LIFT IN OUR AREA DURING THIS PERIOD. WE START TO NOTICE SOME WEAK ISENTROPIC LIFT BETWEEN THE 800-700 MB LAYER BEGINNING WEDNESDAY IN OUR SOUTHERN ZONES. ANALYZING THIS LAYER IN THE FORECASTED SOUNDINGS...WE SEE MOISTURE IN THE LAYER WHERE THE LIFT IS OCCURRING...BUT THE LAYER BELOW 800 MB...AND IN PARTICULAR BELOW 900 MB...IS DRY AND WOULD LIKELY EVAPORATE ANY PRECIPITATION BEFORE IT REACHES THE GROUND. SO THE CHALLENGE NOW IS WILL THE LOWER LAYER SATURATE ENOUGH FROM TOP-DOWN PROCESSES TO ALLOW ANY PRECIPITATION TO REACH THE GROUND? THIS APPEARS TO BE A LOW CHANCE AS THE LIFT DOES NOT LOOK STRONG ENOUGH TO GENERATE ENOUGH PRECIPITATION TO SATURATE THE LAYER ALL THE WAY DOWN TO THE SURFACE. THE RADAR MAY SHOW A LOT OF ECHOES ON WEDNESDAY...BUT DO NOT ANTICIPATE PRECIPITATION WILL REACH THE GROUND. HOWEVER...WILL LEAVE 20 POPS FOR DRIZZLE SOUTHWEST OF A CISCO TO HILLSBORO TO FREESTONE LINE IN CASE SOME LIGHT RAIN DOES REACH THE GROUND. DEPENDING ON THE TIME AND TEMPERATURES...THERE COULD BE A BRIEF PERIOD OF FREEZING DRIZZLE WEST OF I-35. OUR MAIN TIME FRAME OF CONCERN FOR FROZEN PRECIPITATION IS WEDNESDAY NIGHT/EARLY THURSDAY MORNING AS THE ISENTROPIC LIFT CONTINUES BUT ALSO SPREADS NORTH OVER MORE OF THE REGION AND STRENGTHENS. THE MODELS ARE NOT OUTPUTTING ANY QPF DURING THIS 12 HOUR PERIOD FROM 6 PM WEDNESDAY TO 6 AM THURSDAY BECAUSE THEY CONTINUE TO KEEP THE LOWER LEVELS OF THE ATMOSPHERE DRY /AS INDICATED ON THE FORECASTED SOUNDINGS/. THE LOWER LEVELS OF THE ATMOSPHERE WILL EVENTUALLY SATURATE DOWN AS THE ISENTROPIC LIFT CONTINUES BUT THE QUESTION AND CHALLENGE IS WHEN WILL THAT OCCUR. THE DETERMINISTIC MODELS SUGGEST THIS WILL NOT HAPPEN UNTIL AFTER 6 AM THURSDAY WHEN TEMPERATURES ARE ALREADY ABOVE FREEZING /TEMPERATURES ARE EXPECTED TO EVENTUALLY RISE WEDNESDAY NIGHT UNDER THE INFLUENCE OF WARM AIR ADVECTION DUE TO THE ISENTROPIC LIFT/...BUT IT IS POSSIBLE THIS COULD OCCUR DURING THE NIGHT WEDNESDAY. SO WILL KEEP A LOW CHANCE FOR LIGHT RAIN AND/OR LIGHT FREEZING RAIN ALONG AND SOUTH OF A LINE FROM BRECKENRIDGE TO DFW TO EMORY. THE FREEZING RAIN WILL BE MENTIONED ALONG AND WEST OF A LINE FROM WEATHERFORD TO LAMPASAS. IF FREEZING RAIN OCCURS DURING THE TIME FROM 6 PM WEDNESDAY TO 6 AM THURSDAY...WE DO NOT EXPECT SIGNIFICANT IMPACTS AS TEMPERATURES WILL BE WARMING OVERNIGHT AND THE CHANGEOVER TO LIQUID RAIN SHOULD MELT ANY MINIMAL ICE ACCUMULATIONS. HOWEVER...IF TEMPERATURES THAT NIGHT ARE COLDER THAN THEY ARE CURRENTLY FORECAST TO BE AND ARE REALIZED IN THE UPPER 20S...THERE COULD BE SOME MINOR ACCUMULATIONS AND POSSIBLY MINOR IMPACTS FOR A SHORT PERIOD OF TIME DURING THE NIGHT. IF TEMPERATURES WERE TO FALL INTO THE UPPER 20S...THE MOST LIKELY LOCATION FOR THIS TO HAPPEN WOULD BE WEST ON I-35. RAIN CHANCES ARE STILL LOOKING DECENT ACROSS THE REGION ON THURSDAY AND FRIDAY AS THE UPPER LEVEL LOW ALONG THE WEST COAST FINALLY MOVES INTO THE SOUTHERN PLAINS. AGAIN...THIS IS EXPECTED TO REMAIN AS LIQUID RAIN. THERE ARE SOME DIFFERENCES WITHIN THE MODELS REGARDING THE BEST TIMING FOR RAIN CHANCES ON THESE DAYS AND WE WILL HOPEFULLY BE ABLE TO REFINE THEM OVER THE NEXT FEW DAYS. ONE INTERESTING FEATURE TO WATCH WILL BE THE POSSIBILITY OF A SHORTWAVE AHEAD OF THE UPPER LOW ON THURSDAY. THE GFS DEVELOPS THIS SHORTWAVE GIVING US BETTER RAIN CHANCES ON THURSDAY AS A RESULT. THE ECMWF DOES NOT HAVE THIS SHORTWAVE AND THEREFORE HAS BETTER RAIN CHANCES ON FRIDAY AS THE UPPER LEVEL LOW MOVES OVER THE AREA. SOME THUNDER WILL BE POSSIBLE THURSDAY NIGHT AND FRIDAY. ANOTHER FRONT IS EXPECTED BEHIND THIS SYSTEM ON SATURDAY AND IT IS STARTING TO LOOK LIKE THE AIR BEHIND THIS FRONT COULD BE PRETTY COLD AS WELL. 82/JLD && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 46 32 56 34 43 / 10 0 5 5 5 WACO, TX 44 27 59 33 46 / 40 5 5 5 5 PARIS, TX 43 30 51 33 44 / 10 0 5 5 5 DENTON, TX 46 27 56 28 42 / 10 0 5 5 5 MCKINNEY, TX 45 26 54 28 43 / 10 0 5 5 5 DALLAS, TX 47 32 56 35 44 / 20 0 5 5 5 TERRELL, TX 43 29 55 34 45 / 20 0 5 5 5 CORSICANA, TX 43 31 56 35 46 / 40 5 5 5 5 TEMPLE, TX 43 27 61 34 46 / 50 5 5 5 5 MINERAL WELLS, TX 47 29 57 28 40 / 10 0 5 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 79/82
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
1022 PM CST Sat Dec 27 2014 .DISCUSSION... See 06z aviation discussion below. && .AVIATION... Light rain and snow will continue through the overnight hours for parts of the area primarily affecting FST. Ceilings will gradually get lower throughout the night and be at the lowest from 12z to 15z, but ceilings are expected to improve by 18z Sunday. Winds will be light and variable overnight and will shift to the southwest by the afternoon with some possible gusts. && .PREV DISCUSSION... /ISSUED 855 PM CST Sat Dec 27 2014/ UPDATE... Update on the status of the Winter Storm Warning for the Davis and Apache Mountains, Marfa and Alpine areas and Winter Weather Advisory for western Pecos County. DISCUSSION... IR satellite imagery was showing cloud tops cooling over southwest Texas this evening ahead of a shortwave trough over Mexico. At 28/0245Z, radar returns were showing bands of precipitation streaking northeastward over the Warning and Advisory areas. A few calls to Marfa, Alpine and Fort Davis yielded reports of snow falling in those areas, with near 1" of accumulation 7 WNW of Alpine as of 28/0130Z and snow beginning to stick in Alpine at 28/02Z, with the same in Fort Davis. The latest NAM is trickling in, and indicates snow will continue to fall over southwest Texas tonight. Since 4 to 6 inches of snow are still possible in these areas, the Winter Storm Warning will remain in effect until 28/09Z. Further, north and east there is a dry layer in the low to mid levels so precipitation will have to moisten this layer for appreciable precipitation to hit the ground. When it does later tonight, surface temperatures are a little warmer and snow accumulations should only be 1 to 2 inches in western Pecos County. Therefore, the Winter Weather Advisory will continue. Think precipitation will be too light any further northward or eastward for any expansion of the Winter Weather Advisory. Will continue to monitor. && PREV DISCUSSION... /ISSUED 400 PM CST Sat Dec 27 2014/ DISCUSSION... Current observations continue to show intermittent light snow continuing over portions of southeast New Mexico and the western Permian Basin. Significant snows have ended over the Guadalupe Mountains and across Lea County New Mexico. The HRRR and other models suggest that lingering precipitation over these northern areas will continue to wane while redevelopment will occur over the higher elevations of SW Texas beginning later this afternoon into evening. While indications are that the positive tilt upper trough is weakening/filling as it moves across the area, which is a negative against significant snow, current QFP for this evening and BUFKIT sounding interrogation suggests that snow redevelopment is likely...especially over the higher elevations of SW Texas. The Marfa Plateau and the Davis Mountains could see significant snowfall tonight. The western half of Pecos county could also see some minor snow accumulations. For now, will issue a winter storm warning for heavy snow for higher elevations of Presidio, Jeff Davis, and Brewster County. A winter weather advisory will be issued for Pecos County. Both the warning and advisory will be extended into the overnight period. However, most of the activity will probably occur this evening. As this upper trough rapidly exits the area tomorrow morning, zonal upper flow is expected. Surface lee trough development just east of the Rockies will result in a quick warmup for our area tomorrow and Monday. However, a significant cool down is forecast for later Monday into Tuesday. The big question for now is what type of precipitation will fall next week. With shallow cold air in place and an expected elevated warm later, indications are that freezing drizzle will the predominant precipitation type most of next week. && .MAF WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...WINTER WEATHER ADVISORY until 3 AM CST Sunday FOR THE FOLLOWING ZONES... Pecos. WINTER STORM WARNING until 3 AM CST Sunday FOR THE FOLLOWING ZONES... Big Bend Area...Davis/Apache Mountains Area... Marfa Plateau. && $$ 99 Follow us on Facebook and Twitter at: http://facebook.com/NWSMidland http://twitter.com/NWSMidland Check us out on the internet at: http://weather.gov/midland
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
637 PM EST MON DEC 29 2014 .SYNOPSIS... COLD SURFACE HIGH PRESSURE WILL CONTINUE TO WEDGE DOWN FROM THE NORTH ALONG THE APPALACHIANS TONIGHT WHILE A WEAK UPPER LEVEL DISTURBANCE IS EXPECTED TO PASS FROM WEST TO EAST ACROSS THE AREA TONIGHT THROUGH EARLY TUESDAY. VERY LIGHT PRECIPITATION ASSOCIATED WITH THIS FEATURE IS EXPECTED TO CHANGE OVER TO SNOW ACROSS THE NORTHERN PORTION OF THE REGION...WITH ACCUMULATIONS OF AN INCH OR LESS...MAINLY ALONG AND NORTH OF U.S. 460. DRY BUT CONTINUED COLD HIGH PRESSURE WILL BEGIN TO PUSH IN FROM THE WEST LATER TUESDAY AND LAST UNTIL LATE IN THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... AS OF 635 PM EST MONDAY... MADE A FEW MINOR ADJUSTMENTS TO EXISTING SET OF GRIDS TO BUMP UP PROBABILITY OF PRECIPITATION TO ACCOUNT FOR WIDESPREAD RAIN AND DRIZZLE NOW FALLING ACROSS MUCH OF THE NEW RIVER VALLEY NORTH TOWARD THE ALLEGHANY HIGHLANDS. DESPITE AREAL EXTENT OF PRECIPITATION...AMOUNTS CONTINUE TO BE LIGHT...GENERALLY ONLY AROUND 0.01 INCH/PER HOUR. LATEST UPPER-AIR SOUNDING...RELEASED ABOUT 30 MINUTES AGO...SHOWS LOWEST 3K FEET AGL STILL ABOVE FREEZING AND NEARLY SATURATED...SO IT WILL TAKE MUCH OF THE EVENING...PERHAPS INTO THE EARLY MORNING HOURS...TO DRIVE SNOW LEVELS DOWN FROM HIGHEST RIDGES TO MOUNTAIN VALLEY AREAS...CONSISTENT WITH PREVIOUS FORECAST THINKING. THEREFORE...SNOWFALL TOTALS STILL NOT EXPECTED TO BECOME PROBLEMATIC AS THE NIGHT PROGRESSES...ESPECIALLY CONSIDERING CURRENT WARM GROUND CONDITIONS AND VERY LIGHT FALL RATES. ALSO MADE A FEW TWEAKS TO HOURLY TEMPS/DEW POINT GRIDS TO REFLECT LATEST MESONET OBSERVATIONS...OTHERWISE REST OF FORECAST FOR TONIGHT STILL LOOKS RIGHT ON TARGET. AS OF 350 PM EST MONDAY... TRICKY FCST OVERNIGHT IN REGARDS TO THE AMOUNTS AND LOCATIONS OF VERY LIGHT PCPN AS A WEAK UPPER WAVE PASSES OVER THE DEEPENING COLD AIR DAMMING WEDGE AS COLD SFC HIGH PRESSURE SPILLS DOWN FROM THE NORTH. MODEL GUIDANCE ALL QUITE DIFFERENT WITH MAIN OPERATIONAL NCEP MODELS TRENDING UPWARD SOMEWHAT WITH AS MUCH AS A QUARTER TO TWO THIRDS OF AN INCH LIQUID EQUIV...MAINLY OVER THE WESTERN PORTIONS. EVEN ORIGINALLY DRIER GFS NOW AS MUCH AS FOUR TENTHS OF AN INCH OVER THE ALLEGHANY HIGHLANDS. MEANWHILE CONVECTIVE-ALLOWING MODELS GENERALLY LESS THAN TWO TENTHS OF AN INCH. AM LEANING ON THE LIGHT SIDE OF THE QPF OPTIONS...MORE IN LINE WITH IDEA OF MOST OF THE HRRR RUNS...AND POSSIBILITY THAT MORE OF THE PCPN ACTUALLY ENDS UP BACK ACROSS THE FOOTHILLS AND PIEDMONT AGAIN. AM LEAVING SOME VERY LOW LIKELY POPS FOR TONIGHT ACROSS PARTS OF THE MOUNTAINS...WITH HIGHER CHANCE POPS NOW ACROSS THE FOOTHILLS. THE ISSUE OF MOISTURE DEPTH IS STILL CONCERN AS WELL...AND WHILE I DID NOT INCLUDE ANY DRIZZLE IN THE GRIDS...THERE COULD VERY WELL BE PERIODS OF TIME AND PORTIONS OF THE AREA WHERE WE SEE MORE DRIZZLE DUE TO LACK OF ICE CRYSTAL GROWTH ALOFT. THIS WOULD CUT DOWN ON ANY OF THE ALREADY LIGHT SNOW ACCUMS IF AND WHERE THIS HAPPENS. WARM NOSE DOES NOT SEEM TO BE PRESENT IN ANY MODEL SOUNDINGS...SO GOING WITH EITHER RAIN OR SNOW...AND SO SFC TEMPS WILL BE THE KEY TO THAT CHANGEOVER. AS FAR AS THE TEMPS GO...ALREADY GETTING COLDER THIS AFTERNOON THAN WE EARLIER ANTICIPATED...AND SOME HIGHER ELEVATIONS HAVE REPORTS SOME VERY LIGHT SNOW. THUS LOWERED TEMPS THROUGH EVENING AND OVERNIGHT A FEW DEGREES FROM PREVIOUS FORECAST WHERE WEDGE IS EXPECTED TO BE THE STRONGEST...AND THIS RESULTS IN A SLIGHTLY EARLIER CHANGEOVER FROM LIGHT RAIN TO LIGHT SNOW...BUT EXCEPT FOR HIGHER ELEVATIONS...THIS WILL STILL BE AFTER MIDNIGHT. BOTTOM LINE IS ONLY VERY LIGHT AMOUNTS OF SNOW ACCUM EXPECTED LATE TONIGHT AND IN THE EARLY MORNING HOURS TUESDAY...AND IT WILL LIKELY HAVE TROUBLE STICKING AS WELL EXCEPT FOR HIGHEST ELEVATIONS. HAVE DUSTING TO LESS THAN AN INCH GENERALLY NORTH OF U.S. 460...AND DOWN THE BLUE RIDGE TO NEAR MEADOWS OF DAN. MAYBE AN INCH TO ALMOST TWO ALONG HIGHEST RIDGES OF ALLEGHANY HIGHLANDS AND ALONG BLUE RIDGE PARKWAY NORTH OF PEAKS OF OTTER. MOST ROADS NOT EXPECTED TO SEE ANY ACCUMULATION. ANY LINGERING PCPN EVAPORATES QUICKLY BY MIDDAY TUESDAY AS SHORT WAVE PASSES BY AND DRIER AIR FROM NORTH CONTINUES TO FILTER IN. WESTERLY FLOW AT RIDGE TOP LEVEL DEVELOPS BUT VERY WEAK FLOW AND LITTLE MOISTURE TO WORK WITH SO NO ISSUES WITH ANY UPSLOPE SNOW SHOWERS IN FAR WEST IT APPEARS. MAX TEMPS MAY BE TRICKY WITH SOME SUNSHINE LATE IN THE DAY...BUT THIS COULD BE TOO LATE FOR LOW SUN ANGLE TO HAVE MUCH IMPACT...SO FOR NOW GOING ON COLD SIDE OF GUIDANCE WITH ONLY ABOUT A 5-7 DEGREE RISE FROM OVERNIGHT LOWS. ABOVE FREEZING BY LATE MORNING SO ANY MINOR AMOUNTS OF SNOW THAT DOES FALL WILL BE GONE BY NOON MOST LIKELY. FINALLY...COLD WEDGE WILL KEEP SOME AREAS OF FOG AND LOW CEILINGS AROUND...MOST ESPECIALLY NEAR THE BLUE RIDGE...BUT ALSO SOME OF THE MTN VALLEYS AS WELL...SO BLANKED THE FOOTHILLS AND WESTWARD WITH PATCHY FOG THROUGH TOMORROW MORNING IN THE FORECAST GRIDS BUT THIS MAY LINGER THROUGH MUCH OF THE DAY IN SPOTS UNTIL THE WEAK WESTERLY FLOW CAN PUSH EAST. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 200 PM EST MONDAY... A LARGE AREA OF HIGH PRESSURE WILL BUILD SOUTH FROM THE ROCKIES LATE TUESDAY...THEN INTO THE SOUTHEAST U.S. BY THURSDAY EVENING KEEPING DRY WEATHER FOR OUR AREA DURING THIS PORTION OF THE FORECAST. ADJUSTED TEMPS DOWN A FEW DEGREES WEDNESDAY MORNING AND WEDNESDAY AFTERNOON UNDER GOOD COLD AIR ADVECTION. BY THURSDAY MORNING MODELS ARE IN GOOD AGREEMENT THAT SFC HIGH NOSES INTO OUR AREA ALLOWING VALLEY WINDS TO DIMINISH. THIS COMBINED WITH THE DRY AIR MASS IN PLACE SHOULD ALLOW TEMPS TO DROP BELOW GUIDANCE VALUES. THE EXCEPTION WILL BE ON THE RIDGETOPS WHERE 850MB WINDS WILL KEEP TEMPS WARMER. HEIGHTS RISE ON THURSDAY AS AN UPPER RIDGE BEGINS TO BUILD IN THE CENTRAL U.S. IN ADVANCE OF A SOUTHWEST U.S. UPPER LOW. THIS...COMBINED WITH DOWNSLOPING WINDS...SHOULD ALLOW FOR A NICE RECOVERY IN TEMPS THURSDAY. WENT A DEGREE OR TWO ABOVE GUIDANCE FOR HIGHS. ONLY OTHER CHANGE TO THE FORECAST WAS TO INCREASE THE WINDS ABOVE 3500 FEET WEDNESDAY AND THURSDAY AS A SWIFT MOVING NORTHERN STREAM SHORTWAVE PASSES THROUGH THE EASTERN GREAT LAKES THROUGH NEW ENGLAND DURING THIS TIME. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 235 PM EST MONDAY... DRY AND SEASONABLY COOL WEATHER IS EXPECTED OVER THE BLACKSBURG FORECAST AREA FRIDAY MORNING AS A WEAK SHORT WAVE IN NORTHERN STREAM SCOOTS EAST THROUGH NEW ENGLAND...WITH COOL HIGH PRESSURE BUILDING SOUTHWESTWARD IN ITS WAKE. HOWEVER...MUCH OF THE REST OF THE LONG TERM FORECAST FROM FRIDAY AFTERNOON INTO MONDAY APPEARS TO BE MUCH MORE UNCERTAIN...WITH SIGNIFICANT AND PERSISTENT DISPARITY EXISTING BETWEEN THE LONGER- TERM MODELS IN REFLECTING STRENGTH AND PLACEMENT OF NORTHERN STREAM...AND ITS INFLUENCE ON SOUTHERN STREAM CLOSED LOW SOUTH OF THE FOUR CORNERS AREA ON FRIDAY AFTERNOON THAT IS FORECAST TO GRADUALLY LIFT NORTHEAST AND FILL AS IT PROGRESSES FROM THE SOUTHERN PLAINS UP THROUGH THE OHIO VALLEY OVER THE WEEKEND. ECMWF MAINTAINS A MORE PERSISTENT CLOSED UPPER LOW THAT IS MUCH LESS AMPLIFIED...YET LESS PROGRESSIVE AND FURTHER SOUTH...RESULTING IN INCREASING ISENTROPIC LIFT AND RAIN MOVING INTO AT LEAST THE SOUTHWESTERN HALF OF THE BLACKSBURG FORECAST AREA BY/DURING FRIDAY AFTERNOON...BUT NOT ENDING UNTIL PASSAGE OF OPENING/WEAKENING UPPER TROF ON SUNDAY NIGHT. GFS...WHICH REFLECTS A MORE AMPLIFIED...YET EVENTUALLY MORE PROGRESSIVE AND NORTHERN SYSTEM PLACEMENT...HOLDS BACK RAIN SHIELD UNTIL SATURDAY DUE TO INFLUENCE OF LARGER AND STRONGER DRY SURFACE HIGH PRESSURE SYSTEM OVER NEW ENGLAND. GFS ALSO THE COLDER OF THE LONGER RANGE SOLUTIONS...SINCE STRONGER SURFACE RIDGE TO NORTHEAST WOULD LOCK COOL-WEDGE IN PLACE OVER THE BLACKSBURG FORECAST AREA. HOWEVER...BEING MORE PROGRESSIVE...RAIN EVENT ENDS A BIT EARLIER THAN ECMWF SOLUTION...ON SUNDAY AFTERNOON WITH PASSAGE OF UPPER TROF...BUT WITH PERHAPS SOME COLD ADVECTION UPSLOPE PRECIPITATION CONTINUING ACROSS THE WESTERN FLANKS OF THE APPALACHIANS UNTIL AROUND DAYBREAK MONDAY. BOTH MODELS HAVE BEEN INCONSISTENT IN TIMING AND PLACEMENT OF SYSTEM THOUGH THIS TIMEFRAME FOR AT LEAST THE PAST SEVERAL RUNS...WHICH IS NOT ALL THAT SURPRISING CONSIDERING ACTIVE NORTHERN STREAM CLASHING WITH INITIALLY CLOSED AND STAGNANT SOUTHERN STREAM SYSTEM...SO MODEL BLEND/ENSEMBLE APPROACH BEST TO APPLY FOR LONG TERM FORECAST UNTIL CONFIDENCE INCREASES IN MOVING TOWARD ANY PARTICULAR SOLUTION. NEITHER MODEL INDICATING THAT THICKNESSES WILL BE ESPECIALLY CRITICAL FOR P-TYPE ISSUES...MEANING A MAINLY WET RATHER THAN WHITE FORECAST OVER THE WEEKEND. HOWEVER...IF COLDER GFS SOLUTION VERIFIES...THICKNESSES MAY BE CLOSE ENOUGH TO CRITICAL VALUES NORTH OF HIGHWAY 64 TO WARRANT AT LEAST A NOMINAL INSERTION OF A P-TYPE MIX DURING TIME OF PRECIPITATION ONSET...AND PERHAPS FOLLOWING PASSAGE OF MAIN SYSTEM IN THE NORTHWESTERN MOUNTAINS ON SUNDAY NIGHT PROVIDED THAT POST FRONTAL COLD ADVECTION IS SUFFICIENTLY STRONG. REGARDLESS OF TIMING AND PLACEMENT DIFFERENCES...ALL LONGER RANGE MODELS INDICATE THAT MONDAY WILL BE DRY FOLLOWING PASSAGE OF THE MAIN UPPER SYSTEM...WITH ANY ADDITION SOUTHERN STREAM ENERGY LIKELY TO BE DEFLECTED TO OUR SOUTH AS NORTHERN STREAM TROFING GRADUALLY STRENGTHENS AND AMPLIFIES FROM THE UPPER GREAT LAKES EAST INTO THE NORTHEASTERN PORTION OF THE NATION FROM MONDAY INTO THE MID WEEK PERIOD. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 635 PM EST MONDAY... IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE AT ALL AIRPORTS THROUGH AT LEAST TONIGHT...AND FOR WESTERN AIRPORTS EVEN INTO EARLY PART OF TUESDAY...UNDER THE INFLUENCE OF COLD AIR DAMMING WHICH IS ONLY STRENGTHENING WITH TIME. LOW CONFIDENCE FOR WHEN CONDITIONS MAY BEGIN TO BREAK OUT AND LIFT ON TUESDAY...AND MAY HAPPEN AT KBLF SOONER THAN TAF CURRENTLY INDICATES. MORE CONFIDENT THAT KROA AND KLYH WILL IMPROVE TO AT LEAST MVFR DURING TUESDAY MORNING AS DRIER AIR CONTINUES TO FILTER DOWN FROM NORTH...AND EVENTUALLY KDAN AS WELL BEFORE 18Z. IN ADDITION...ALL AIRPORTS EXCEPT FOR KDAN SHOULD SEE SOME VERY LIGHT RAIN CHANGE TO LIGHT SNOW AFTER MIDNIGHT TONIGHT...BUT NOT EXPECTED TO STICK MUCH AT ALL EXCEPT FOR THE HIGHER ELEVATION AIRPORTS SUCH AS KLWB...AND KBCB. NOT SURE IT WILL BE COLD ENOUGH TO REALLY STICK AT KBLF AND KROA OR KLYH. KDAN LIKELY WILL NOT EVEN SEE CHANGEOVER. IN ANY CASE...SNOW AMOUNTS WOULD ONLY APPROACH AN INCH IN THE WORSE-CASE SCENARIO. EXTENDED DISCUSSION... A LARGE AREA OF HIGH PRESSURE WILL START TO NOSE INTO THE AREA FROM THE WEST LATER TUESDAY INTO WEDNESDAY. THIS WILL RESULT IN GRADUAL CLEARING...CLOUD BASES LIFTING INTO THE MVFR CATEGORY TUESDAY AFTERNOON AND TUESDAY NIGHT...BEFORE DISSIPATING WEDNESDAY AND RETURN OF VFR. VFR WILL THEN PREVAIL THROUGH AT LEAST THURSDAY BEFORE TRENDING DOWN AGAIN FOR THE WEEKEND PER RETURN OF MOISTURE FROM THE SOUTHWEST. THE NEXT LOW PRESSURE SYSTEM TO AFFECT THE AREA WILL COME FROM THE SOUTHWEST...LOW PRESSURE DEVELOPING ALONG THE TEXAS GULF COAST FRIDAY...THEN MOVING NORTHEAST ACROSS THE MID ATLANTIC REGION FOR THE WEEKEND. THIS SYSTEM LOOKS LIKE IT WILL PRODUCE A MULTI-DAY PERIOD OF SUB-VFR CONDITIONS...BEGINNING AS EARLY AS FRIDAY NIGHT...AND LINGERING THROUGH THE WEEKEND. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...SK NEAR TERM...SK/WERT SHORT TERM...PH LONG TERM...WERT AVIATION...PM/SK/WERT
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1216 AM EST SUN DEC 28 2014 .SYNOPSIS... A WEAK COLD FRONT WILL DRIFT SOUTHEAST INTO THE MOUNTAINS TODAY BEFORE SPILLING SOUTH OF THE REGION LATER SUNDAY NIGHT. WEAK WAVES OF LOW PRESSURE TRACKING ALONG THE BOUNDARY TODAY INTO MONDAY MORNING WILL BRING PERIODS OF MOSTLY LIGHT RAIN TODAY THROUGH EARLY MONDAY. COLD HIGH PRESSURE WILL SLOWLY BUILD EAST INTO THE REGION BEHIND THE FRONT FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH SUNDAY NIGHT/... AS OF 830 PM EST SATURDAY... CLOUDS HAVE QUICKLY OVERSPREAD THE REGION THIS EVENING ASSOCIATED WITH A LEAD FAINT MID LEVEL IMPULSE IN ADVANCE OF THE MAIN PIECES OF SOUTHERN STREAM SUPPORT TO THE SW. HOWEVER MOSTLY OF THE MID DECK VARIETY WITH ANY -RA OR SPRINKLES CONFINED JUST WEST OF THE CWA CLOSER TO THE UPSTREAM FRONT/JET. LATEST HRRR SHOWS SOME INTERMITTENT -RA PERHAPS MAKING IT TO THE BLUE RIDGE AFTER MIDNIGHT BUT WITHOUT MUCH ORGANIZATION GIVEN LINGERING DRY AIR ALOFT PER EVENING SOUNDINGS...AND BEST LIFT WEST-NW OF THE REGION UNTIL DAYBREAK. THUS SLOWED DOWN MAIN CORRIDOR OF POPS A BIT MORE OVERNIGHT AS MAY BE DURING SUNDAY BEFORE BETTER COVERAGE ARRIVES AS SEEN VIA THE LATEST NAM. OTHER CONCERN WITH LOW TEMPS AS THE CURRENT CLOUD CANOPY HAS TENDED TO STOP FALLS FOR THE MOMENT WITH MANY LOCATIONS STILL IN THE 50S. IR PICS DO SHOW SOME BREAKS HEADING THIS WAY OUT OF TN SO STILL SOME POTENTIAL TO SEE SOME SPOTS SNEAK BACK DOWN GIVEN DRY AIR. HOWEVER APPEARS EVEN WITH SOME ADDED COOLING BY LATE RAINFALL THAT WILL NEED TO RAISE LOWS A CAT OR TWO MOST SPOTS. PREVIOUS VALID DISCUSSION AS OF 340 PM EST SATURDAY... THE AFTERNOON MILD TEMPERATURES ALONG WITH INCREASING CLOUD COVER FROM THE SOUTHWEST MAY RESULT IN SOME MILD TEMPS OVERNIGHT TONIGHT...ESPECIALLY IN THE WEST WHERE CLOUD COVER WILL BE THICKEST SOONER. IN THE EAST...CLOUDS WILL NOT THICKEN UP UNTIL SOME LATE AFT/EARLY EVENING RADIATIONAL COOLING...SO MAY END UP BEING COOLER IN PARTS OF THE PIEDMONT THERE THAN IN MTNS. WENT WITH OR SLIGHTLY WARMER THAN GUIDANCE AT SOME OF THE HIGHER ELEVATION LOCATIONS...AND WITH COOLER MAV GUIDANCE IN EAST. OTHERWISE...MAIN ISSUE OVERNIGHT IS TIMING OF PRECIP HEADED NORTHEAST OUT OF GULF COAST AREA WITH SHORT WAVE AHEAD OF THE APPROACHING COLD FRONT FROM THE WEST. A LITTLE CONCERNED ABOUT AMOUNT OF CONVECTION DOWN THERE NOW ACTING IN SOME WAY TO ROB SOME OF THE MOISTURE...AS WELL AS VERY DRY AIRMASS WE CURRENTLY HAVE IN PLACE THAT COULD HELP SLOW DOWN ARRIVAL. MODEL TRENDS...AND HIGH RES CONVECTIVE-ALLOWING VERSIONS...NOW HOLD PRECIP OFF UNTIL MAYBE JUST BEFORE 12Z IN FAR SW AND FAR WEST PART OF AREA. SO LOWERED POPS SLIGHTLY...MAINLY FROM 06-12Z TIME FRAME....AND ESPECIALLY ACROSS NORTHEAST PART OF AREA WHERE IT LOOKS LIKELY THAT NO PRECIP WILL REACH PAST ROANOKE BEFORE THEN. WHATEVER DOES REACH FAR SW BY EARLY MORNING WILL BE QUITE LIGHT. FOR SUNDAY...MAIN BAND OF STEADIER RAIN WILL MOVE IN FROM MID MORNING THROUGH EARLY AFTERNOON. LEANING TOWARD NAM/ECWMF/SREF IDEA THAT BEST CHANCES WILL BE FROM BLUE RIDGE WEST...WITH MORE SCATTERED LIGHTER PRECIP INITIALLY IN PIEDMONT...ALTHOUGH 12Z GFS WOULD DISAGREE. THEN THIS WAVE MOVES OUT BY LATER AFTERNOON BUT WITH LINGERING MOISTURE KEEPING HIGH POPS IN WEST AND REDUCED TO CHANCE IN PIEDMONT FOR LATE IN DAY INTO EARLY EVENING. NEXT WAVE THEN ARRIVES ALONG BOUNDARY BY EVENING...AND THIS ZONE OF STEADIER RAIN APPEARS MOST LIKELY TO TAKE A TRACK A LITTLE MORE TO SOUTH OF FIRST ONE...WITH FOOTHILLS TO PIEDMONT GETTING MOST OF THE MODERATE RAINFALL. OTHER THAN GFS...SEEING SOME TRENDS OVER LOWERING AMOUNTS WITH THIS...WHICH IS PARTLY REFLECTIVE OF WEAKENING UPPER WAVE BEING STRETCHED WITH TIME AS WELL AS SOME MOISTURE STEALING FROM CONVECTION WELL TO SOUTH. NOT LOOKING AT NEARLY ENOUGH RAINFALL FOR ANY PROBLEMS. SEE THE HYDRO SECTION BELOW FOR MORE DETAILS ON THAT. TEMPS THROUGH THIS PERIOD WILL BE MILD...ALTHOUGH SOME COOLER AIR WILL FILTER INTO WESTERN APPALACHIAN SLOPES BY EARLY MONDAY MORNING...BUT NOT COLD ENOUGH FOR ANY SNOW...EVEN AT HIGHEST ELEVATIONS. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM EST SATURDAY... THE LAST WAVE IN THE SERIES ALONG A SLOW-MOVING CLOD FRONT SHOULD BE EXITING TOWARD THE ATLANTIC COAST FROM EARLY MONDAY THROUGH THE DAY WITH POPS SLOWLY DIMINISHING. COLD AIR ADVECTION BEHIND THIS SYSTEM SLOW TO DEVELOP DURING THE DAY SO HIGHS SHOULD BE ABLE TO BOUNCE BACK SOME FROM MORNING LOWS AND WILL GENERALLY RANGE FROM UPPER 30S NW TO UPPER 40S SE UNDER STILL MOSTLY CLOUDY SKIES. LINGERING RAIN SHOWERS ON THE BACK END OF THIS SYSTEM WILL ENCOUNTER THE INCREASING SOUTHWARD SPILL OF COLDER AIR AND MAY CAUSE A CHANGE OVER TO SNOW SHOWERS IN THE HIGHER TERRAIN OF THE NORTHWEST CWA BY EVENING MONDAY AND HAVE INTRODUCED VERY LIGHT SNOW ACCUMULATIONS..LESS THAN 1 INCH IN THOSE COLDER AREAS...MAINLY GREENBRIER AND BATH COUNTIES. COLDER AIR EMANATING FROM THE MASSIVE HIGH OVER THE WESTERN AND CENTRAL CONUS WILL OOZE EASTWARD AND SOUTHWARD OVERNIGHT MONDAY AND THROUGH THE DAY TUESDAY AS H85 TEMPS FALL BELOW 0C ACROSS THE ENTIRE CWA BY TUESDAY EVENING AND CONTINUE TO SLIP INTO EARLY WEDNESDAY. HIGHS TUESDAY WILL BE CHILLY..RANGING FROM L/M 30S WEST TO MID-40S SE...ACTUALLY A FEW DEGREES BELOW LATE DECEMBER CLIMO. WEDNESDAY MORNING LOWS FALL BACK CLOSE TO ABOUT NORMAL FOR THIS TIME OF YEAR...NEAR 20F NW TO UPPER 20S SE. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 430 PM EST SATURDAY... LONG RANGE MODELS...AT LEAST FOR WEDNESDAY AND THURSDAY ARE IN AGREEMENT WITH FAIR CONTINUITY AS WE TRANSITION INTO THE NEW YEAR. BROAD UPPER LEVEL TROUGH IS PROGGED TO EXTEND FROM EASTERN CANADA...SOUTHWEST THROUGH THE CENTRAL CONUS INTO A CUTOFF AREA OF LOW PRESSURE OVER SOUTHERN CALIFORNIA. A HIGH AMPLITUDE RIDGE WILL BE POSITIONED OFF THE PAC NW COAST. THIS PATTERN FAVORS COLD TEMPERATURES PERSISTING OVER THE NORTHERN CONTINENTAL UNITED STATES (CONUS) AND SOUTHWARD OVER THE PLAINS...AND MILDER AIR CONFINED TO THE EXTREME SOUTHEAST CONUS...I.E. FLORIDA. FOR THE MID ATLANTIC WE WILL LIKELY END UP IN THE TRANSITION ZONE...OR PRETTY CLOSE TO NORMAL TO FINISH OUT THE WEEK. WORST CASE...WE MAY END UP 5 DEGREES OR SO BELOW NORMAL FOR NEW YEARS DAY...BUT NOTHING EXTREME. AFTER THURSDAY THE MODELS DIVERGE...WHICH IS TO BE EXPECTED SINCE THEY DO NOT HANDLE CUTOFF LOWS VERY WELL...AND ESPECIALLY THOSE THAT EJECT FROM THE DESERT SOUTHWEST. WITHIN THE EVOLVING MEAN PATTERN THE PRIMARY FEATURE OF INTEREST WILL BE THE UPPER LOW WHICH ALL GUIDANCE CLOSES OFF OVER/NEAR CA/AZ INITIALLY BUT THEN DIVERGE ON WHEN THE LOW OPENS UP AND MOVES EAST DURING THE FRIDAY SATURDAY TIME FRAME. THERE IS A FAIR AMOUNT OF MODEL/ENSEMBLE SPREAD REGARDING THE TIMING AND TO A SOMEWHAT LESSER DEGREE TRACK OF THE UPPER LOW. THE OPERATIONAL RUN OF THE GFS IS 12-24 HOURS FASTER THAN THE ECMWF...WHICH MAKES A DIFFERENCE IN WHETHER IT PRECIPITATES HERE ON FRIDAY VS SATURDAY. THIS HIGH SPREAD/LOW CONFIDENCE FORECAST FAVORS AN ENSEMBLE MEAN APPROACH FOR BOTH FRIDAY AND SATURDAY...THE FORECAST REFLECTING A BLEND...WITH CHC PRECIP BOTH FRIDAY AND SATURDAY...THE GREATEST POPS FAVORING FRIDAY NIGHT WHERE THE BLENDED SOLUTIONS OVERLAP. TIMING AND TRACK OF THE SYSTEM WILL ALSO DETERMINE P-TYPE. TEMPERATURES LOOK TO BE BORDERLINE CRITICAL FRIDAY...SUGGESTING AT LEAST SOME WINTRY MIX IF PRECIP ARRIVES FRIDAY MORNING. IF ONSET HOLDS OFF UNTIL LATER FRIDAY...THE P-TYPE WILL BE MOSTLY RAIN. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... AS OF 1145 PM EST SATURDAY... VFR CONTINUES TO PREVAIL TONIGHT WITH SOMEWHAT LOWER CIGS IN SPOTS OVER THE WEST WHERE HAVE SEEN A FEW SPRINKLES. STILL EXPECTING OVERALL CIGS TO REMAIN IN THE 4-6K FT RANGE UNDER AREAS OF MID DECK OVERNIGHT SO APPEARS WILL STAY MAINLY VFR AT ALL LOCATIONS FOR AT LEAST A FEW MORE HOURS. DEEPER MOISTURE AHEAD OF THE UPSTREAM COLD FRONT AND ASSOCIATED INITIAL WAVE WILL PUSH NE INTO THE SE WEST VA SITES AROUND DAYBREAK SUNDAY WITH MORE IN THE WAY OF WIDESPREAD MVFR CIGS WEST OF THE BLUE RIDGE SUNDAY MORNING. THIS WILL ALSO BE FOLLOWED BY PATCHY LIGHT RAIN WHICH SHOULD ARRIVE AT KBLF/KLWB JUST PRIOR TO SUNRISE IF NOT A BIT SOONER...BUT MAINLY LIGHT...THUS OVERALL VFR VSBYS IN ANY PRECIP EARLY SUNDAY. FIRST WAVE OF LIGHT RAIN WILL ALSO SCOOT ACROSS SUNDAY MORNING WITH MAINLY VFR CIGS AND VSBYS IN THE SPOTTY COVERAGE FROM THE BLUE RIDGE EAST...AND MVFR OVER THE WEST ESPCLY KBLF/KLWB. APPEARS THIS WILL MAINLY GO TO MOISTEN THE COLUMN BEFORE ANOTHER ROUND OF STEADIER RAIN ARRIVES OVER THE FAR WEST/NW IN THE AFTERNOON. THIS IS WHEN IT APPEARS THAT CIGS/VSBYS WILL DETERIORATE QUICKER PENDING HOW FAST THINGS BECOME SATURATED IN THE WAKE OF THE INITIAL RAINFALL. THIS LOOKS TO HAPPEN IN THE MID/LATE AFTERNOON TIME FRAME ESPCLY SE WEST VA SITES WHERE LIKELY WITHIN STEADIER RAINFALL...AND BLUE RIDGE LOCATIONS GIVEN SOMEWHAT TRAPPED LOW LEVEL MOISTURE. STILL WONT GO AS LOW AS THE LATEST NAM IN SHOWING WIDESPREAD LIFR/IFR AT ALL SITES BY LATE IN THE DAY OR EARLY EVENING. HOWEVER TRENDING INTO SOLID IFR WEST...MIX OF MVFR/OCNL IFR BLUE RIDGE INCLUDING KBCB/KROA...AND MAINLY MVFR AT KDAN/KLYH PENDING DEGREE OF PRECIP THEY SEE SUNDAY MORNING. FRONT WILL SLOWLY PUSH EAST ACROSS THE AREA SUNDAY NIGHT AS ANOTHER AREA OF LOW PRESSURE TRACKS UP THE BOUNDARY BRINGING MORE WIDESPREAD RAINFALL TO SOUTHERN/EASTERN SECTIONS INTO EARLY MONDAY. THIS LOOKS TO BE THE BEST TIME TO SEE WIDESPREAD IFR CIGS AND MVFR/IFR VSBYS AT ALL LOCATIONS EXCLUDING PERHAPS KLWB THAT MAY STAY WITH ONLY MVFR CONDITIONS JUST NORTH OF THE MAIN PRECIP SHIELD. OTRW EXPECTING PLENTY OF LOW CLOUDS...-RA AS WELL AS DRIZZLE/FOG TO COVER MUCH OF THE REGION SUNDAY NIGHT...WITH ONLY SLOW IMPROVEMENT INTO MONDAY IN THE WAKE OF THE FRONT GIVEN LOW LEVEL NE FLOW. EXTENDED DISCUSSION... THE FRONT DRIFTS OFF TO THE SE MONDAY NIGHT INTO TUESDAY WHILE LEAVING PLENTY OF RESIDUAL LOW LEVEL MOISTURE IN ITS WAKE. HIGH CONFIDENCE IN STAYING SUB-VFR MONDAY NIGHT WITH MORE FOG/DRIZZLE AROUND OVERNIGHT. SLOW DRYING TO TAKE SHAPE ON TUESDAY AS A LARGE AREA OF HIGH PRESSURE STARTS TO NOSE IN FROM THE WEST. HOWEVER MAY TAKE UNTIL AFTERNOON FOR EASTERN SITES TO RETURN TO VFR WHILE LINGERING LOW CLOUDS COULD CAUSE MVFR CIGS TO PERSIST OVER THE WEST UNTIL LATE IN THE DAY. SOME SPOTTY LIGHT RAIN OR WINTRY PRECIP MAY ALSO OCCUR EARLY TUESDAY AS A WEAK TROUGH OF LOW PRESSURE REDEVELOPS OVER THE MOUNTAINS. OTRW HIGH PRESSURE BUILDS EAST WEDNESDAY INTO THURSDAY WITH GOOD FLYING CONDITIONS RETURNING UNDER VFR. && .HYDROLOGY... AS OF 300 PM EST SATURDAY... RIVER MODEL RUNS FROM THE VARIOUS RFCS FROM THIS MORNING INCORPORATE THE UPCOMING WET PERIOD WITH BASIN AVERAGE QPF VALUE ACROSS THE HYDROLOGIC SERVICE AREA BASINS RANGING FROM ABOUT 0.75 INCHES IN THE UPPER JAMES TO AS MUCH AS 1.20 INCHES OVER THE LOWER DAN. THE RESULTING RIVER FORECASTS BRING STAGE UP SEVERAL FEET...BUT STILL WELL WITHIN BANKFULL...SO NO FLOODING ISSUES EXPECTED. SOILS ARE FAIRLY WET BUT RAINFALL RATES ARE EXPECTED TO BE MODEST SO FLASH FLOODING NOT AN ISSUE EITHER. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/SK NEAR TERM...JH/SK SHORT TERM...PC LONG TERM...PM AVIATION...JH/RCS/SK HYDROLOGY...PC
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML

Area Forecast Discussion National Weather Service Spokane WA 955 PM PST SAT DEC 27 2014 .SYNOPSIS... Scattered snow showers will continue overnight into Sunday with light to moderate accumulations in the Idaho Panhandle...Cascade Crest...and portions of Eastern Washington. Bitterly cold northeast winds will develop by Monday and continue into Monday night. Temperatures will be well below average with dry conditions most of next week as arctic high pressure settles over the Inland Northwest. && .DISCUSSION... Steady snow has ended and the region is transitioning into an unstable atmosphere. The most consistent snow shower activity will be in the oropgraphically favored areas including the Idaho Mountains, Cascade Crest, and Blue Mtns. However, there are at least two vorticity maximums spinning in a line from Ern WA to Central BC on the cyclonic side of the upper level jet. Each of these will bring the potential for clusters of snow showers...some which could bring quick bursts of 1-2 inches. HRRR suggest far NE WA may encounter one of these waves now and another in a few hours so opted to leave Winter Storm Warning going with wording of localized accumulations. It is conceivable that these same local accumulations hit the Okanogan Valley, Spokane Area, or Washington Palouse but given the low confidence and above freezing temperatures from Spokane to Pullman, opted to cancel highlights. && .AVIATION... 06Z TAFs: The region has transitioned to the cool and unstable side of the Polar Jet and steady wdsprd pcpn has waned. The focus now will be several smaller scale circulations evident via satellite from SE WA to Central BC. These waves will dig south through the region during the next 12-18 hours bringing clusters of rain/snow showers eventually becoming all snow. Any accumulations will be localized and carry low confidence. Moist boundary layer conditions will deliver a low confidence ceiling/vis fcst as well and fcst may be optimistic. A push of cooler and drier air from Canada will arrive Sunday evening swinging winds around to the NE and incr the chance for light snow showers with the frontal passage. Accumulations with this feature will be light and snow will be more light and fluffy compared to the wet nature observed Saturday. /sb && .PRELIMINARY POINT TEMPS/POPS... Spokane 27 31 18 21 5 14 / 80 30 20 10 0 0 Coeur d`Alene 27 31 17 20 3 14 / 100 50 20 10 0 0 Pullman 29 33 19 23 3 14 / 100 70 30 30 10 0 Lewiston 32 38 24 29 9 19 / 100 60 40 30 10 0 Colville 26 33 20 24 1 18 / 60 30 20 10 0 0 Sandpoint 27 32 18 20 2 15 / 100 40 20 10 10 0 Kellogg 26 30 15 17 -3 11 / 100 70 40 20 10 0 Moses Lake 27 33 23 29 8 22 / 20 20 50 30 0 0 Wenatchee 28 34 25 30 12 23 / 20 20 60 40 0 0 Omak 25 29 21 26 4 17 / 20 10 40 20 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Winter Storm Warning until 4 PM PST Sunday for Central Panhandle Mountains-Lewis and Southern Nez Perce Counties. Winter Storm Warning until 4 AM PST Sunday for Coeur d`Alene Area-Idaho Palouse-Northern Panhandle. WA...Winter Storm Warning until 4 PM PST Sunday for Northeast Blue Mountains. Winter Storm Warning until 4 AM PST Sunday for Northeast Mountains. Winter Weather Advisory until 4 AM PST Sunday for East Slopes Northern Cascades. && $$
AREA FORECAST DISCUSSION
NWS PORTLAND OR
929 PM PST SAT DEC 27 2014 .SYNOPSIS...A COLD FRONT HAD MOVED THROUGH SOUTHWEST WASHINGTON EARLIER THIS EVENING...AND WILL FINISH MOVING THROUGH NORTHWEST OREGON BY MIDNIGHT. BRISK ONSHORE FLOW WILL CONTINUE BEHIND THE FRONT TONIGHT AND SUNDAY AND PRODUCE MORE SHOWERS OVER THE AREA... ESPECIALLY OVER THE HIGHER TERRAIN...THEN INCREASE SUNDAY NIGHT INTO MONDAY NIGHT WITH EVEN MORE SHOWERS AS A SECONDARY COLD DISTURBANCE MOVES THROUGH FROM THE NORTH. LOOK FOR OCCASIONAL SNOW TO CONTINUE IN THE CASCADES AND ACROSS THE PASSES INTO MONDAY. COLDER HIGH PRESSURE WILL THEN BUILD INTO THE COLUMBIA BASIN AND CAUSE COLD EAST WINDS TO DEVELOP ACROSS THE AREA MONDAY AFTERNOON AND INCREASE MONDAY NIGHT AND TUESDAY FOR DRY CONDITIONS BUT WITH VERY COLD TEMPERATURES AND ASSOCIATED COLD WIND CHILLS. THE DRY COLD AND BLUSTERY PATTERN WILL CONTINUE MUCH OF THE COMING WEEK...WITH THE NEXT CHANCE FOR SOME PRECIPITATION LATE IN THE WEEK AND NEXT WEEKEND...WITH A POSSIBILITY OF WINTER WEATHER AT LOW ELEVATIONS. && .SHORT TERM...TONIGHT THROUGH TUESDAY...A FAIRLY STRONG COLD FRONT MOVED THROUGH SOUTHWEST WASHINGTON AND MOST OF NORTHWEST OREGON THIS EVENING...WITH VERY GOOD PRECIPITATION AMOUNTS IN THE MOUNTAINS... DECENT AMOUNTS AT THE COAST...AND LESSER AMOUNTS IN THE VALLEYS. THE STEADIER RAIN IS MOSTLY OVER THOUGH THE FRONT DOES LINGER A BIT IN EASTERN LANE COUNTY BUT SHOULD MOVE OUT BY MIDNIGHT. THE MODELS SHOW A PRETTY STEADY STREAM OF ONSHORE FLOW AND SHOWERS COMING IN FROM THE WEST NORTHWEST OVERNIGHT WHICH SHOULD KEEP THE SNOW GOING THE CASCADES. WE MAY SEE SOME RAIN SHADOWING IN THE VALLEYS THOUGH. THE ONSHORE FLOW CONTINUES SUNDAY BUT MAY NOT BE QUITE AS STRONG AS TONIGHT...THEN PICKS UP SUNDAY NIGHT INTO MONDAY AS A TRAILING SECONDARY COLD DISTURBANCE DROPS DOWN FROM THE NORTH SUNDAY NIGHT AND MONDAY MORNING. THIS SHOULD GIVE US AN INCREASE IN THE SHOWERS AND SNOW IN THE CASCADES. WITH HOLIDAY TRAVEL EXPECTED SUNDAY AND POSSIBLY MONDAY...HAVE DECIDED TO CONTINUE THE SNOW ADVISORIES IN THE CASCADES INTO MONDAY. WE MAY SEE SOME ACCUMULATING SNOW IN THE CASCADE FOOTHILLS AND HIGHER COAST RANGE SUNDAY NIGHT INTO MONDAY AS WELL...AS SNOW LEVELS DROP TO AROUND 2000 FEET BY SUNDAY EVENING AND TO NEAR OR BELOW 1000 FEET BY MONDAY MORNING. AMOUNTS COULD GET CLOSE TO ADVISORY THRESHOLDS. AFTER THAT...DRY WEATHER WILL DEVELOP AS COLD HIGH PRESSURE WILL SPREAD DOWN INTO THE COLUMBIA BASIN AND CAUSE COLD EAST WINDS TO DEVELOP THROUGH THE COLUMBIA RIVER GORGE AND UP AND OVER THE CASCADES AND ACROSS THE REMAINDER OF SOUTHWEST WASHINGTON AND NORTHWEST OREGON. THE WINDS WILL DEVELOP BY MONDAY AFTERNOON...AND INCREASE MONDAY NIGHT AND TUESDAY AND BE QUITE STRONG...POSSIBLY ENOUGH FOR SOME AREAS OF TREE DAMAGE AND POWER OUTAGES. THE EAST WINDS WILL USHER IN THE COLDEST AIR MASS OF THE SEASON SO FAR...AND IN COMBINATION WITH THE WIND WILL PRODUCE SOME COLD WIND CHILLS. AN SPECIAL WEATHER STATEMENT HAS BEEN ISSUED DISCUSSING ALL OF THIS. TOLLESON .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...COLD...DRY WEATHER CONTINUES THROUGH THE DAY WEDNESDAY...AS HIGH PRESSURE SITS OVER THE AREA. ECMWF AND GFS ARE STARTING TO KEY IN ON A LOW PRESSURE SYSTEM THAT WILL DIVE DOWN THE COAST LATE THIS WEEK...SHIFTING WINDS BACK TO THE NORTHWEST AND BRINGING PRECIPITATION. THERE IS STILL CONSIDERABLE UNCERTAINTY ON THE TIMING OF THIS SYSTEM...THOUGH. IF THIS PANS OUT AS FORECAST RIGHT NOW...A CHANCE OF WINTRY MIX ALL THE WAY TO THE FLOOR OF THE WILLAMETTE VALLEY IS POSSIBLE INITIALLY THURSDAY NIGHT INTO EARLY FRIDAY. AS THE FRONT MOVES THROUGH TEMPERATURES ARE STILL BELOW FREEZING...UNTIL ONSHORE WINDS AND DAYTIME HEATING CAN BRING TEMPERATURES BACK ABOVE FREEZING LATE FRIDAY MORNING OR AFTERNOON. IF THE FRONT IS SLOWER THAN FORECAST AND MOVES THROUGH DURING THE DAY ON FRIDAY...TEMPERATURES WILL MORE LIKELY BE ABOVE FREEZING KEEPING IT ALL RAIN. RAIN LOOKS TO CONTINUE INTO SATURDAY. -MCCOY && .AVIATION...A COLD FRONT WILL CONTINUE TO MOVE THROUGH THE THE AREA THIS EVENING BRINGING MVFR CONDITIONS TO AREAS NEAR THE FRONT. IN THE WAKE OF THE FRONT...THE STEADY RAIN WILL BECOME MORE SHOWERY AND CONDITIONS WILL GENERALLY IMPROVE TO VFR FOR THE OVERNIGHT HOURS AS COOLER AND MORE UNSTABLE AIR MOVES IN. THERE MAY BE SOME MVFR OR EVEN IFR CONDITIONS IN SOME SHELTERED AREAS WHERE FOG MAY FORM. THE MID-LEVEL C0LD AIR ADVECTION WEAKENS AFTER DAYBREAK SUNDAY...SO THERE IS A CHANCE AN EXTENDED CLEAR PERIOD COULD ALLOW IFR TO LIFR FOG TO FORM...PARTICULARLY AT KEUG. A WEAK LOW PRESSURE WILL DROP SOUTHWARD ACROSS THE AREA SUNDAY EVENING. AS THIS SYSTEM APPROACHES...CONDITIONS COULD DETERIORATE INTO THE MVFR CATEGORY AFTER 4PM SUNDAY. KPDX AND APPROACHES...MAINLY VFR CONDITIONS THIS EVENING AND OVERNIGHT AS MID LEVEL COLD ADVECTION DESTABILIZES THE LOWER ATMOSPHERE IN THE WAKE OF THE FRONTAL PASSAGE. AN OCCASIONAL MVFR CIG WILL BE POSSIBLE...BUT THESE SHOULD BE SHORT LIVED. ADDITIONAL FLIGHT RESTRICTIONS COULD CREEP INTO THE TERMINAL TOWARDS 4PM SUNDAY AFTERNOON AS A WEAK LOW PRESSURE DROPS SOUTHWARD WEST OF THE CASCADES. && .MARINE...A FRONT WILL DROP SOUTHWARD ACROSS THE WATERS THIS EVENING...BRINGING GUSTY NORTHWEST WINDS AND HIGH SEAS TO THE WATERS. WINDS AND SEAS SHOULD BE HIGHEST ACROSS THE NORTHERN COASTAL WATERS WITH SOLID SMALL CRAFT ADVISORY WINDS WITH GUSTS OF 25 TO 30 KT. SEAS SHOULD GENERALLY TOP OUT IN THE 11 TO 13 FT RANGE TOWARDS THE CENTRAL AND NORTH OREGON COAST. EXPECT SEAS TO START SUBSIDING SUNDAY AFTERNOON AND SUNDAY NIGHT...LIKELY DROPPING BELOW 10 FT MONDAY MORNING. A WEAK LOW PRESSURE MAY DEVELOP AND DRIFT SOUTHWARD ACROSS THE INNER WATERS LATE SUNDAY NIGHT OR MONDAY MORNING...BUT IMPACTS TO MARINE INTERESTS WILL BE FAIRLY MINIMAL. AS THE LOW PRESSURE DROPS SOUTH OF THE AREA...OFFSHORE PRESSURE GRADIENTS WILL STRENGTHEN RAPIDLY. THIS WILL ALLOW GUSTY EAST TO NORTHEAST WINDS TO DEVELOP ACROSS THE WATERS FOR THE SECOND HALF OF MONDAY...LASTING THROUGH AT LEAST THE MIDDLE PART OF NEXT WEEK. WITH NO MAJOR WESTERLY SWELLS...SEA CONDITIONS WILL PRIMARILY BE DOMINATED BY WIND WAVES DURING THE PEAK OF THE EAST WINDS, WHICH WILL LIKELY OCCUR MONDAY NIGHT INTO TUESDAY. TW/CN && .PQR WATCHES/WARNINGS/ADVISORIES... OR...WINTER WEATHER ADVISORY UNTIL NOON PST MONDAY FOR CASCADES IN LANE COUNTY-NORTHERN OREGON CASCADES. WA...WINTER WEATHER ADVISORY UNTIL 7 AM PST MONDAY FOR SOUTH WASHINGTON CASCADES. PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST SUNDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 9 AM PST MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM. SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM PST SUNDAY FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 1 PM PST SUNDAY. && $$ 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.
Area Forecast Discussion National Weather Service Spokane WA 852 PM PST SAT DEC 27 2014 .SYNOPSIS... Scattered snow showers will continue overnight into Sunday with light to moderate accumulations in the Idaho Panhandle...Cascade Crest...and portions of Eastern Washington. Bitterly cold northeast winds will develop by Monday and continue into Monday night. Temperatures will be well below average with dry conditions most of next week as arctic high pressure settles over the Inland Northwest. && .DISCUSSION... Steady snow has ended and the region is transitioning into an unstable atmosphere. The most consistent snow shower activity will be in the oropgraphically favored areas including the Idaho Mountains, Cascade Crest, and Blue Mtns. However, there are at least two vorticity maximums spinning in a line from Ern WA to Central BC on the cyclonic side of the upper level jet. Each of these will bring the potential for clusters of snow showers...some which could bring quick bursts of 1-2 inches. HRRR suggest far NE WA may encounter one of these waves now and another in a few hours so opted to leave Winter Storm Warning going with wording of localized accumulations. It is conceivable that these same local accumulations hit the Okanogan Valley, Spokane Area, or Washington Palouse but given the low confidence and above freezing temperatures from Spokane to Pullman, opted to cancel highlights. && .AVIATION... 00Z TAFs: A cold upper level trough and surface low pressure will persist over the region through the next 24 hours. The eastern TAF sites including KGEG...KCOE...KSFF and KPUW will be under threat for IFR and LIFR conditions in snow through 02-03Z as moist isentropic ascent continues. Conditions will improve after 02Z-03Z as a dry slot moves through the region...but deterioration will occur after 06Z with a cold front band of snow showers. KLWS will probably remain VFR through this evening but with snow or rain showers nearby. KMWH and KEAT will benefit from downslope off the cascades for primarily VFR conditions. On Sunday cold air aloft will destabilize the air mass leading to scattered snow showers over the eastern TAF sites promoting occasional periods of low MVFR or IFR conditions in snow. /MJF && .PRELIMINARY POINT TEMPS/POPS... Spokane 27 31 18 21 5 14 / 80 30 20 10 0 0 Coeur d`Alene 27 31 17 20 3 14 / 100 50 20 10 0 0 Pullman 29 33 19 23 3 14 / 100 70 30 30 10 0 Lewiston 32 38 24 29 9 19 / 100 60 40 30 10 0 Colville 26 33 20 24 1 18 / 60 30 20 10 0 0 Sandpoint 27 32 18 20 2 15 / 100 40 20 10 10 0 Kellogg 26 30 15 17 -3 11 / 100 70 40 20 10 0 Moses Lake 27 33 23 29 8 22 / 20 20 50 30 0 0 Wenatchee 28 34 25 30 12 23 / 20 20 60 40 0 0 Omak 25 29 21 26 4 17 / 20 10 40 20 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Winter Storm Warning until 4 PM PST Sunday for Central Panhandle Mountains-Lewis and Southern Nez Perce Counties. Winter Storm Warning until 4 AM PST Sunday for Coeur d`Alene Area-Idaho Palouse-Northern Panhandle. WA...Winter Storm Warning until 4 PM PST Sunday for Northeast Blue Mountains. Winter Storm Warning until 4 AM PST Sunday for Northeast Mountains. Winter Weather Advisory until 4 AM PST Sunday for East Slopes Northern Cascades. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
500 PM CST SUN DEC 28 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 200 PM CST SUN DEC 28 2014 CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE NORTHWESTERN U.S. AND BRITISH COLUMBIA...A COLLECTION OF WEAK SHORTWAVES OVER WYOMING AND NEBRASKA AND AN UPPER LOW OVER NORTHERN ONTARIO. DESPITE A MAINLY ZONAL FLOW COMING ACROSS THE FORECAST AREA...A COLD FRONT WAS EVIDENT AT THE SURFACE DROPPING SOUTH INTO THE AREA. THIS FRONT EXTENDED FROM NORTHERN LOWER MI TO LA CROSSE TO SIOUX CITY IA. LOW CLOUDS WITH A FEW FLURRIES WERE EVIDENT IN A 100 MILE WIDTH ZONE BEHIND THE FRONT...WHILE SKIES WERE MAINLY SUNNY AHEAD OF IT. 925MB TEMPS OF -6 TO -10C AND SUN HAS ALLOWED TEMPERATURES TO MOSTLY CLIMB INTO THE 20S WITH A FEW NEAR 30 READINGS IN FAR SOUTHWEST WISCONSIN. COLDEST READINGS HAVE BEEN OVER THE NORTHWEST 1/3 OF THE AREA WITH MORE SNOW AND BEING FIRST TO EXPERIENCE THE FROPA. MUCH COLDER AIR TRYING TO SINK SOUTH BEHIND THE FRONT WITH 925MB TEMPS IN THE -15 TO -20C RANGE OVER MUCH OF NORTH DAKOTA INTO NORTHERN MN. THE MAIN FEATURE OF INTEREST FOR THE SHORT TERM IS THE COLLECTION OF WEAK SHORTWAVES OVER WYOMING AND NEBRASKA. MODELS ARE IN GOOD AGREEMENT BRINGING THESE SHORTWAVES ACROSS IOWA AND SOUTHERN PORTIONS OF THE FORECAST AREA LATE TONIGHT INTO MONDAY MORNING. WITH THESE SHORTWAVES COMES INCREASING MID LEVEL FRONTOGENESIS...MOSTLY IN THE WAKE OF THE CURRENT COLD FRONT DROPPING SOUTH THROUGH THE FORECAST AREA. PROBLEM IS THAT AT THE TIME OF THE BEST MID LEVEL LIFT...THERE IS ENOUGH DRY AIR BELOW THE MID CLOUDS TO ABSORB MUCH OF THE SNOW PRODUCTION. WHEN THAT DRY AIR MOSTLY SATURATES...THE LIFT IS GONE. THEREFORE...A MENTION OF FLURRIES AS THE PREVIOUS FORECAST HAD SEEMS REASONABLE. MOST 28.12Z GUIDANCE OF QPF CONTINUES TO PRODUCE A DRY FORECAST TOO. COLD ADVECTION BEHIND THE COLD FRONT PASSAGE WILL BE THE MAIN FACTOR IN DROPPING TEMPERATURES TONIGHT...SINCE CLOUDS SHOULD BE IN PLACE FOR MOST LOCATIONS. 925MB TEMPS FALL TO -10C SOUTH TO -15C NORTH... WHICH SHOULD ALLOW TEMPERATURES TO DROP INTO THE SINGLE DIGITS NORTH TO NEAR 20 SOUTH. THE COLDEST READINGS ARE EXPECTED IN TAYLOR/CLARK COUNTIES WHERE SOME CLEARING IS POSSIBLE THIS EVENING BEFORE MID/HIGH CLOUDS OVERSPREAD. FURTHER 925MB TEMP COOLING TAKES PLACE ON MONDAY DUE TO PERSISTENT NORTHERLY FLOW. READINGS DROP TO -13C SOUTH TO -17C NORTH...WHICH MEANS HIGHS WILL STRUGGLE TO CLIMB MUCH THAN A FEW DEGREES ABOVE THE LOWS TONIGHT. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 200 PM CST SUN DEC 28 2014 THE MAIN STORY MONDAY NIGHT THROUGH TUESDAY NIGHT IS THE COLD. ALL MODELS CONTINUE TO DROP A 1050-1060MB HIGH SOUTHWARD ALONG THE LEE SIDE OF THE ROCKIES DURING THIS TIME...WITH COLD ADVECTION DOWNSTREAM OF THE HIGH OVER THE FORECAST AREA. 925MB TEMPS FALL TO -16 TO -19C BY 12Z TUESDAY AND TO AROUND -20C BY 06Z WEDNESDAY. MUCH OF THE TIME PERIOD SHOULD BE MOSTLY CLEAR...OUTSIDE OF SOME PASSING CLOUDS TUESDAY AFTERNOON AND EVENING ASSOCIATED WITH A SHORTWAVE TROUGH OF ARCTIC ORIGIN MOVING THROUGH. THE SOUTHEAST HALF OF THE FORECAST AREA WILL STAY WARMER DUE TO THE FACT OF NO SNOW ON THE GROUND...BUT STILL EXPECT CHILLY READINGS...ESPECIALLY TUESDAY NIGHT WITH THE COLDEST AIR IN PLACE. A PERSISTENT NORTHWEST BREEZE SHOULD EXIST SINCE WE ARE NOT UNDER THE CENTER OF THE HIGH...THEREFORE... WIND CHILLS BECOME A FACTOR. ADVISORIES ARE LIKELY TO BE NEEDED BOTH NIGHTS...PARTICULARLY OVER NORTH CENTRAL WI AND POSSIBLY PORTIONS OF SOUTHEAST MN AND NORTHEAST IA TOO. SOME MODERATION TAKES PLACE WEDNESDAY INTO THURSDAY / NEW YEARS EVE AND DAY / IN RESPONSE TO A POTENT SHORTWAVE TROUGH DIGGING INTO NORTHERN ONTARIO AND LAKE SUPERIOR. HOWEVER...THIS MODERATION TAKES PLACE AT THE EXPENSE OF HIGHER WINDS...WHICH MEANS A PERSISTENT WIND CHILL FACTOR. FIRST...THE WESTERLY WINDS ADVECT DOWNSLOPED AIR OFF THE ROCKIES TOWARDS THE FORECAST AREA...BOOSTING 925MB TEMPS TO AROUND -14C BY 00Z THU AND -8 TO -10C BY 00Z FRI. THESE READINGS SHOULD HELP BRING HIGHS BACK UP INTO THE TEENS ON WEDNESDAY AND MOSTLY INTO THE 20S ON THURSDAY. NOW REGARDING THE WINDS...925MB SPEEDS ARE PROGGED TO INCREASE TO THE 35 TO 45 KT RANGE AT 00Z THU BEFORE RELAXING SOME FOR DURING THE DAY THURSDAY. WITH PLENTY OF SUN ON WEDNESDAY...WE SHOULD SEE SOME GOOD MIXING OF THOSE WINDS. RIGHT NOW IT APPEARS GUSTS MAY TOP OUT AROUND 30 KT...HIGHEST IN SOUTHEAST MN...BUT WORTH MONITORING OVER THE NEXT FEW DAYS TO SEE IF THESE END UP HIGHER. SOMETHING ELSE TO MONITOR ON THURSDAY IS POSSIBLE LIGHT SNOW AS A COLD FRONT AND SHORTWAVE TROUGH DROP THROUGH THE NORTHERN PORTION OF THE FORECAST AREA. HAVE ADDED SOME CHANCE POPS TO LOCATIONS NORTH OF I-90. FOR FRIDAY INTO SATURDAY...WE NEED TO WATCH CLOSELY THE EVOLUTION AND TRACK OF AN UPPER LOW THAT COMES OUT OF THE SOUTHWESTERN U.S.. THIS UPPER LOW...FORMED BY THE CURRENT STRONG SHORTWAVE DIVING SOUTH THROUGH THE NORTHWESTERN U.S....IS PRESENTLY PROGGED TO GET LIFTED THROUGH MISSOURI AND INTO LOWER MI ON SATURDAY. SOME WARM ADVECTION SNOW COULD BEGIN TO APPROACH THE REGION AS EARLY AS LATE FRIDAY WELL DOWNSTREAM OF THIS UPPER LOW...OR FROM A FRONTOGENESIS BAND TRACKING ACROSS THE NORTHERN U.S.. HOWEVER...FRIDAY NIGHT INTO SATURDAY SEEM TO BE THE BETTER CHANCES IN SEEING A COLD CONVEYOR BELT BAND OF SNOW TRACK ACROSS THE FORECAST AREA FROM THE UPPER LOW. IF THIS SYSTEM TRACKS FARTHER NORTHWEST...MAY END UP WITH AN ADVISORY LEVEL SNOW. NOTE THAT THE 28.12Z ECMWF/UKMET/CANADIAN PRESENT A MUCH SLOWER IDEA WITH THE UPPER LOW...RESULTING IN A MUCH DRIER SCENARIO...THUS PLENTY OF UNCERTAINTY AND ONLY 30-40 PERCENT PRECIPITATION CHANCES. POST THE SATURDAY SYSTEM...A STRONG SURGE OF ARCTIC AIR LOOKS POISED TO IMPACT THE REGION FOR SUNDAY INTO EARLY NEXT WEEK. IT COULD BE NEARLY AS COLD AS THE JANUARY 5-7TH 2014 ARCTIC OUTBREAK...AND JUST HAPPENS TO BE THE SAME DATES. THE 28.12Z MODEL CYCLE DEPICTS THE GFS COLDER WHILE THE ECMWF WAS WARMER AND A BIT MORE DELAYED...WAITING UNTIL MONDAY TO DRIVE THE COLD AIR IN. NEEDLESS TO SAY...STAY TUNED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 500 PM CST SUN DEC 28 2014 BAND OF 2-3 KFT CLOUDS SINKING SOUTHWARD ACROSS THE REGION EARLY THIS EVENING. RAGGED AND THINNER ACROSS SOUTHEAST MN...MAKING LOW CIGS LESS ASSURED AT KRST. THESE LOWER CIGS SHOULD SINK SOUTH OF KRST/KLSE BY 06Z...WITH SOME HIGH CLOUDINESS TO CONTEND WITH THROUGH MONDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM....AJ AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
200 PM CST SUN DEC 28 2014 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 200 PM CST SUN DEC 28 2014 CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE NORTHWESTERN U.S. AND BRITISH COLUMBIA...A COLLECTION OF WEAK SHORTWAVES OVER WYOMING AND NEBRASKA AND AN UPPER LOW OVER NORTHERN ONTARIO. DESPITE A MAINLY ZONAL FLOW COMING ACROSS THE FORECAST AREA...A COLD FRONT WAS EVIDENT AT THE SURFACE DROPPING SOUTH INTO THE AREA. THIS FRONT EXTENDED FROM NORTHERN LOWER MI TO LA CROSSE TO SIOUX CITY IA. LOW CLOUDS WITH A FEW FLURRIES WERE EVIDENT IN A 100 MILE WIDTH ZONE BEHIND THE FRONT...WHILE SKIES WERE MAINLY SUNNY AHEAD OF IT. 925MB TEMPS OF -6 TO -10C AND SUN HAS ALLOWED TEMPERATURES TO MOSTLY CLIMB INTO THE 20S WITH A FEW NEAR 30 READINGS IN FAR SOUTHWEST WISCONSIN. COLDEST READINGS HAVE BEEN OVER THE NORTHWEST 1/3 OF THE AREA WITH MORE SNOW AND BEING FIRST TO EXPERIENCE THE FROPA. MUCH COLDER AIR TRYING TO SINK SOUTH BEHIND THE FRONT WITH 925MB TEMPS IN THE -15 TO -20C RANGE OVER MUCH OF NORTH DAKOTA INTO NORTHERN MN. THE MAIN FEATURE OF INTEREST FOR THE SHORT TERM IS THE COLLECTION OF WEAK SHORTWAVES OVER WYOMING AND NEBRASKA. MODELS ARE IN GOOD AGREEMENT BRINGING THESE SHORTWAVES ACROSS IOWA AND SOUTHERN PORTIONS OF THE FORECAST AREA LATE TONIGHT INTO MONDAY MORNING. WITH THESE SHORTWAVES COMES INCREASING MID LEVEL FRONTOGENESIS...MOSTLY IN THE WAKE OF THE CURRENT COLD FRONT DROPPING SOUTH THROUGH THE FORECAST AREA. PROBLEM IS THAT AT THE TIME OF THE BEST MID LEVEL LIFT...THERE IS ENOUGH DRY AIR BELOW THE MID CLOUDS TO ABSORB MUCH OF THE SNOW PRODUCTION. WHEN THAT DRY AIR MOSTLY SATURATES...THE LIFT IS GONE. THEREFORE...A MENTION OF FLURRIES AS THE PREVIOUS FORECAST HAD SEEMS REASONABLE. MOST 28.12Z GUIDANCE OF QPF CONTINUES TO PRODUCE A DRY FORECAST TOO. COLD ADVECTION BEHIND THE COLD FRONT PASSAGE WILL BE THE MAIN FACTOR IN DROPPING TEMPERATURES TONIGHT...SINCE CLOUDS SHOULD BE IN PLACE FOR MOST LOCATIONS. 925MB TEMPS FALL TO -10C SOUTH TO -15C NORTH... WHICH SHOULD ALLOW TEMPERATURES TO DROP INTO THE SINGLE DIGITS NORTH TO NEAR 20 SOUTH. THE COLDEST READINGS ARE EXPECTED IN TAYLOR/CLARK COUNTIES WHERE SOME CLEARING IS POSSIBLE THIS EVENING BEFORE MID/HIGH CLOUDS OVERSPREAD. FURTHER 925MB TEMP COOLING TAKES PLACE ON MONDAY DUE TO PERSISTENT NORTHERLY FLOW. READINGS DROP TO -13C SOUTH TO -17C NORTH...WHICH MEANS HIGHS WILL STRUGGLE TO CLIMB MUCH THAN A FEW DEGREES ABOVE THE LOWS TONIGHT. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 200 PM CST SUN DEC 28 2014 THE MAIN STORY MONDAY NIGHT THROUGH TUESDAY NIGHT IS THE COLD. ALL MODELS CONTINUE TO DROP A 1050-1060MB HIGH SOUTHWARD ALONG THE LEE SIDE OF THE ROCKIES DURING THIS TIME...WITH COLD ADVECTION DOWNSTREAM OF THE HIGH OVER THE FORECAST AREA. 925MB TEMPS FALL TO -16 TO -19C BY 12Z TUESDAY AND TO AROUND -20C BY 06Z WEDNESDAY. MUCH OF THE TIME PERIOD SHOULD BE MOSTLY CLEAR...OUTSIDE OF SOME PASSING CLOUDS TUESDAY AFTERNOON AND EVENING ASSOCIATED WITH A SHORTWAVE TROUGH OF ARCTIC ORIGIN MOVING THROUGH. THE SOUTHEAST HALF OF THE FORECAST AREA WILL STAY WARMER DUE TO THE FACT OF NO SNOW ON THE GROUND...BUT STILL EXPECT CHILLY READINGS...ESPECIALLY TUESDAY NIGHT WITH THE COLDEST AIR IN PLACE. A PERSISTENT NORTHWEST BREEZE SHOULD EXIST SINCE WE ARE NOT UNDER THE CENTER OF THE HIGH...THEREFORE... WIND CHILLS BECOME A FACTOR. ADVISORIES ARE LIKELY TO BE NEEDED BOTH NIGHTS...PARTICULARLY OVER NORTH CENTRAL WI AND POSSIBLY PORTIONS OF SOUTHEAST MN AND NORTHEAST IA TOO. SOME MODERATION TAKES PLACE WEDNESDAY INTO THURSDAY / NEW YEARS EVE AND DAY / IN RESPONSE TO A POTENT SHORTWAVE TROUGH DIGGING INTO NORTHERN ONTARIO AND LAKE SUPERIOR. HOWEVER...THIS MODERATION TAKES PLACE AT THE EXPENSE OF HIGHER WINDS...WHICH MEANS A PERSISTENT WIND CHILL FACTOR. FIRST...THE WESTERLY WINDS ADVECT DOWNSLOPED AIR OFF THE ROCKIES TOWARDS THE FORECAST AREA...BOOSTING 925MB TEMPS TO AROUND -14C BY 00Z THU AND -8 TO -10C BY 00Z FRI. THESE READINGS SHOULD HELP BRING HIGHS BACK UP INTO THE TEENS ON WEDNESDAY AND MOSTLY INTO THE 20S ON THURSDAY. NOW REGARDING THE WINDS...925MB SPEEDS ARE PROGGED TO INCREASE TO THE 35 TO 45 KT RANGE AT 00Z THU BEFORE RELAXING SOME FOR DURING THE DAY THURSDAY. WITH PLENTY OF SUN ON WEDNESDAY...WE SHOULD SEE SOME GOOD MIXING OF THOSE WINDS. RIGHT NOW IT APPEARS GUSTS MAY TOP OUT AROUND 30 KT...HIGHEST IN SOUTHEAST MN...BUT WORTH MONITORING OVER THE NEXT FEW DAYS TO SEE IF THESE END UP HIGHER. SOMETHING ELSE TO MONITOR ON THURSDAY IS POSSIBLE LIGHT SNOW AS A COLD FRONT AND SHORTWAVE TROUGH DROP THROUGH THE NORTHERN PORTION OF THE FORECAST AREA. HAVE ADDED SOME CHANCE POPS TO LOCATIONS NORTH OF I-90. FOR FRIDAY INTO SATURDAY...WE NEED TO WATCH CLOSELY THE EVOLUTION AND TRACK OF AN UPPER LOW THAT COMES OUT OF THE SOUTHWESTERN U.S.. THIS UPPER LOW...FORMED BY THE CURRENT STRONG SHORTWAVE DIVING SOUTH THROUGH THE NORTHWESTERN U.S....IS PRESENTLY PROGGED TO GET LIFTED THROUGH MISSOURI AND INTO LOWER MI ON SATURDAY. SOME WARM ADVECTION SNOW COULD BEGIN TO APPROACH THE REGION AS EARLY AS LATE FRIDAY WELL DOWNSTREAM OF THIS UPPER LOW...OR FROM A FRONTOGENESIS BAND TRACKING ACROSS THE NORTHERN U.S.. HOWEVER...FRIDAY NIGHT INTO SATURDAY SEEM TO BE THE BETTER CHANCES IN SEEING A COLD CONVEYOR BELT BAND OF SNOW TRACK ACROSS THE FORECAST AREA FROM THE UPPER LOW. IF THIS SYSTEM TRACKS FARTHER NORTHWEST...MAY END UP WITH AN ADVISORY LEVEL SNOW. NOTE THAT THE 28.12Z ECMWF/UKMET/CANADIAN PRESENT A MUCH SLOWER IDEA WITH THE UPPER LOW...RESULTING IN A MUCH DRIER SCENARIO...THUS PLENTY OF UNCERTAINTY AND ONLY 30-40 PERCENT PRECIPITATION CHANCES. POST THE SATURDAY SYSTEM...A STRONG SURGE OF ARCTIC AIR LOOKS POISED TO IMPACT THE REGION FOR SUNDAY INTO EARLY NEXT WEEK. IT COULD BE NEARLY AS COLD AS THE JANUARY 5-7TH 2014 ARCTIC OUTBREAK...AND JUST HAPPENS TO BE THE SAME DATES. THE 28.12Z MODEL CYCLE DEPICTS THE GFS COLDER WHILE THE ECMWF WAS WARMER AND A BIT MORE DELAYED...WAITING UNTIL MONDAY TO DRIVE THE COLD AIR IN. NEEDLESS TO SAY...STAY TUNED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1130 AM CST SUN DEC 28 2014 AVIATION WEATHER PRETTY GOOD TODAY BUT WATCHING BAND OF MVFR CEILINGS SLOWLY PUSHING SOUTH WITH WEAK FRONT. THIS CLOUD BAND HAS BEEN THINING A BIT BUT STILL EXPECTING IT TO TRACK SOUTH CLOSER TO INTERSTATE 90 CORRIDOR THIS AFTERNOON. TIMING OF THAT SAME BAND CLEARING OUT A BIT MORE TOUGH BUT GUIDANCE SUGGESTS EARLY MONDAY MORNING WITH VFR CEILINGS REMAINING IN PLACE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION.....SHEA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1057 PM PST MON DEC 29 2014 ...WINDY AND COLDER WEATHER ON THE WAY FOR THE END OF 2014... .SYNOPSIS...A FAST MOVING STORM SYSTEM WILL MOVE SOUTHEAST ACROSS NEVADA TONIGHT BRINGING A SLIGHT CHANCE OF SHOWERS MAINLY IN THE HILLS. COLDER AND WINDIER CONDITIONS WILL SETTLE OVER THE AREA TUESDAY AND WEDNESDAY BEHIND THIS SYSTEM. A WARMING TREND WILL RETURN BY LATE THIS WEEK. && .DISCUSSION...AS OF 9:00 PM PST MONDAY...A COLD UPPER LEVEL LOW OVER SOUTHEAST OREGON WILL DRIVE SOUTHEAST DURING THE NIGHT WITH THE TROUGH AXIS MOVING THROUGH THE AREA LATE TONIGHT. THE SYSTEM HAS VERY LITTLE MOISTURE BUT RECENT HRRR MODEL RUNS HAVE SHOWN ISOLATED CONTOURS OF ONE TO TWO-HUNDREDTHS OF PRECIP IN THE HILLS. A SLIGHT CHANCE OF SHOWERS IS IN THE FORECAST FOR TONIGHT BUT MOST LIKELY ANY PRECIP WILL FALL OVER THE HILLS. WINDS WILL INCREASE AS THIS TROUGH AXIS MOVES THROUGH WITH MODELS SHOWING 925 MB WINDS INCREASING TO 35-45 KT RANGE TUESDAY MORNING. MODELS ALSO SHOW DECENT OMEGA VALUES AFTER THE TROUGH PASSES INDICATING THAT WINDS ALOFT COULD MIX DOWN TO THE SURFACE. THEREFORE A WIND ADVISORY IS IN EFFECT BEGINNING TUESDAY MORNING IN THE NORTH AND EAST BAY HILLS AND SANTA CRUZ MOUNTAINS FOR GUSTS UP TO 55-60 MPH...AND MIDDAY TUESDAY FOR THE REST OF THE SFO BAY AREA WITH GUSTS TO 40-45 MPH. STRONG WINDS WILL CONTINUE THROUGH TUESDAY NIGHT AND MAY EVEN BE SLIGHTLY STRONGER THAN TUESDAY MORNING. THESE STRONG WINDS WILL BRING DOWN SOME TREES AND CAUSE POWER OUTAGES AS THE SOIL REMAINS FAIRLY WET FROM RAINS EARLIER THIS MONTH. WINDS WILL DECREASE BY MIDDAY WEDNESDAY AS THE LOW MOVES FURTHER EAST AND AN UPPER LEVEL RIDGE BUILDS IN FROM THE WEST. COLD NORTHERLY FLOW WILL CONTINUE OVER THE AREA THROUGH WEDNESDAY AND WITH THE WINDS DIMINISHING IT WILL SET UP A COLD NIGHT FOR NEW YEARS EVE. TEMPERATURES WILL DROP INTO THE 20S IN MANY OF THE INLAND VALLEYS WITH LOWER TO MID 30S IN THE URBAN AREAS AROUND OAKLAND-SAN JOSE. A FROST ADVISORY MAY BE NEEDED FOR MOST OF THE SFO BAY AREA WEDNESDAY NIGHT. TEMPERATURES WILL SLOWLY WARM UP THURSDAY THROUGH SUNDAY AS THE UPPER LEVEL RIDGE MOVES OVER THE WEST COAST. IN THE LONG RANGE...MODELS CONTINUE TO STRUGGLE WITH WHETHER THERE WILL BE RAIN IN OUR CWA AROUND THE MIDDLE OF NEXT WEEK. LATEST GFS AND ECMWF INDICATE A CHANCE FOR RAIN FOR AT LEAST THE NORTHERN PART OF THE DISTRICT. && .AVIATION...AS OF 10:45 PM PST MONDAY...THE LIMITED BAND OF LOW AND MID LEVEL CLOUDINESS ASSOCIATED WITH THE MOSTLY DRY COLD FRONT SWEEPING SOUTHWARD THROUGH CENTRAL CALIFORNIA IS NOW PASSING THROUGH THE MONTEREY BAY REGION. BEHIND IT SKIES ARE EXPECTED TO REMAIN MOSTLY CLEAR THROUGH THE NIGHT...AS THE BOUNDARY LAYER AIR MASS LOOKS TO REMAIN SUFFICIENTLY DRY AND WELL MIXED AS TO PRECLUDE ANY DEVELOPMENT OF FOG OR LOW CLOUDS. ON TUESDAY HOWEVER...COUPLING OF A RAPIDLY INCREASING NORTH TO SOUTH PRESSURE GRADIENT WITH STRONG NORTH-TO-NORTHEAST FLOW ALOFT WILL RESULT IN INCREASINGLY STRONG WINDS OVER THE DISTRICT. KEY QUESTIONS ARE WHEN...WHERE...AND TO WHAT DEGREE THESE WILL MIX DOWN TO THE SURFACE AT LOW ELEVATIONS. HIGH RESOLUTION LOCAL MODEL OUTPUT INDICATES THIS WILL IN FACT PROGRESSIVELY OCCUR AT SFO BAY AREA TAF SITES DURING THE DAY ON TUESDAY...WITH WINDS LIKELY BECOMING LOCALLY STRONG AND GUSTY BY AFTERNOON. VICINITY OF KSFO...MOSTLY CLEAR SKIES THROUGH THE REMAINDER OF THE NIGHT AND ALL DAY ON TUESDAY AS THE POST-FRONTAL AIR MASS REMAINS DRY AND WELL MIXED. WINDS VEER NORTH-NORTHEASTERLY TOMORROW AND ARE LIKELY TO BECOME STRONG AND GUSTY BY AFTERNOON. MEDIUM-TO-HIGH CONFIDENCE. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WITH GENERALLY LIGHT WINDS THROUGH THE PERIOD. MEDIUM CONFIDENCE. && .MARINE...AS OF 01:38 PM PST MONDAY...STRONG HIGH PRESSURE WILL BUILD OVER THE GREAT BASIN INCREASING NORTHERLY WINDS THROUGH WEDNESDAY. WINDS DECREASE WEDNESDAY NIGHT AND THURSDAY AS THE HIGH WEAKENS. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...SCA...PIGEON PT TO PT PINOS 0-10 NM SCA...PIGEON PT TO PT PINOS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 3 AM SCA...PT ARENA TO PT REYES 0-10 NM SCA...PT ARENA TO PT REYES 10-60 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PT REYES TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: W PI AVIATION/MARINE: BLIER VISIT US AT WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS RENO NV
936 PM PST MON DEC 29 2014 .UPDATE... JUST A FEW MINOR FORECAST TWEAKS THIS EVENING. WE ARE STILL ON TRACK FOR A LIGHT SNOWFALL LATER TONIGHT. HOWEVER, THE INITIAL BAND ASSOCIATED WITH SHALLOWER LIFT/MOISTURE HAS MOVED TO BETWEEN RENO AND CARSON CITY AND IS NOT THE MAIN BAND OF SNOW FOR THE AREA. THE MAIN EVENT FOR THE RENO-SPARKS AND CARSON CITY-MINDEN AREAS LOOKS TO BE LATER TONIGHT AS THE MAIN UPPER COLD POOL/TROUGH AXIS APPROACHES. THIS IS EVIDENCED BY INCREASING RADAR RETURNS UP AROUND PYRAMID LAKE AND COLDER CLOUD TOPS IN THE INFRARED SATELLITE NORTH OF RENO. ALONG WITH A LIGHT SNOWFALL FOR MOST OF WESTERN NEVADA, THE INSTABILITY AND DEEPER MOISTURE WITH THE COLD POOL SHOULD COMBINE WITH UPSLOPE FLOW AGAINST THE CARSON RANGE TO PRODUCE LOCALLY HIGHER SNOWFALL TOTALS IN THE FOOTHILLS SOUTH AND WEST OF RENO. SNYDER && .SYNOPSIS... A STRONG COLD FRONT WILL PUSH THROUGH THE AREA TONIGHT. SNOWFALL IS POSSIBLE WITH POTENTIAL TRAVEL IMPACTS FOR THE TUESDAY MORNING COMMUTE ALONG THE HIGHWAY 395 CORRIDOR. STRONG WINDS ARE EXPECTED TO PRODUCE ROUGH CONDITIONS ON AREA LAKES ALONG WITH POSSIBLE AREAS OF BLOWING SNOW. TEMPERATURES WILL BE BITTER COLD WITH WIND CHILLS IN THE SINGLE DIGITS AND NEGATIVE VALUES HEADING INTO THE NEW YEAR. A MILDER PATTERN WILL RETURN FOR THE WEEKEND. && .PREVIOUS DISCUSSION... /ISSUED 242 PM PST MON DEC 29 2014/ SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT VISIBLE SATELLITE IMAGERY SHOWING A COLD UPPER LOW ACROSS THE PACIFIC NORTHWEST WITH COOLING IR COLD TOPS ALONG A STRONG COLD FRONT OVER SOUTHERN OREGON. THIS FRONT WILL QUICKLY DRIVE SOUTH THROUGH NORTHERN NEVADA TONIGHT INTO TUESDAY MORNING PROVIDING THE POTENTIAL FOR A FEW INCHES OF SNOWFALL AND BITTER COLD HEADING INTO THE NEW YEAR. HI-RES MESOSCALE AND GLOBAL MODELS ARE BEGINNING TO CLUE INTO THE FORMATION OF BANDED SNOWFALL CREATED BY STRONG LOW LEVEL FRONTOGENESIS AND MOISTURE IN A REGION OF FAVORABLE MICROPHYSICS FOR ICE CRYSTAL GROWTH. THESE COLD TEMPERATURES WILL MAKE FOR LIGHT AND FLUFFY SNOW. SOME DISAGREEMENT ON TIMING BUT LARGELY LOOKING FOR SNOWFALL IN THE RENO/CARSON CITY REGION AS EARLY 8PM BUT THE MOST FAVORABLE WINDOW LOOKS TO BE BETWEEN 10PM-4AM. A WINTER WEATHER ADVISORY HAS BEEN POSTED FOR THE SIERRA FRONT WHICH INCLUDES THE HWY 395 CORRIDOR SOUTH THROUGH MINDEN AND GARDNERVILLE. THE ADVISORY ALSO COVERS PORTIONS OF WESTERN MINERAL AND SOUTHERN LYON COUNTY. GENERALLY LOOKING FOR SNOWFALL IN THE 1-2" RANGE FROM RENO TO CARSON CITY WITH HIGHER AMOUNTS SOUTH WHERE UPSLOPE FORCING WILL ADD ADDITIONAL LIFT. LOCATIONS ALONG THE EASTERN SLOPES OF THE CARSON RANGE, EASTERN ALPINE CO, NORTHERN MONO COUNTY COULD SEE MORE IN THE 2-4" RANGE. SLIDERS ARE NOTORIOUSLY DIFFICULT SYSTEMS TO FORECAST SO WILL PUT FORECAST CONFIDENCE IN SNOW AMOUNTS IN THE MEDIUM CATEGORY. THE OTHER IMPACTS WITH THIS SYSTEM WILL BE SOME GUSTY CONDITIONS BEHIND THE FRONT AS A STRONG PRESSURE GRADIENT DEVELOPS ACROSS WESTERN NEVADA AND THE SIERRA. EXPECTING TO SEE SUSTAINED WINDS IN THE 15-25 MPH RANGE WITH GUSTS UP TO 40-45 MPH OUT OF THE EAST WHICH PUTS THIS JUST BELOW ADVISORY CRITERIA ACROSS WESTERN NEVADA. HAVE HOWEVER POSTED A LAKE WIND ADVISORY FOR PYRAMID LAKE AND A WIND ADVISORY ACROSS THE TAHOE BASIN. EXPECTING HAZARDOUS BOATING CONDITIONS ON AREA LAKES WITH GUSTS NEAR 45 MPH EXPECTED IN THE TAHOE BASIN WITH HIGHEST WAVES ALONG THE ATYPICAL WESTERN SHORES. WINDS WILL SHARPLY INCREASE IN ELEVATION WITH VERY STRONG WINDS EXPECTED MAINLY ABOVE 8,500 FEET WHERE GUSTS BETWEEN 80-100+ MPH ARE POSSIBLE. THIS MAY ALSO POSE THE RISK FOR TREE FALLS ACROSS THE TAHOE BASIN PARTICULARLY FOR TREES WEAKENED FROM THE PAST WIND EVENT. THE SAME STRONG WINDS HOLD TRUE ACROSS HIGH TERRAIN THROUGH MONO COUNTY BUT THE STRONGEST WINDS WILL REMAIN OVER THE CREST AND ALONG THE WESTERN SLOPES OF THE SIERRA WHERE VERY STRONG DOWNSLOPE WINDS LOOK FAVORABLE. OTHERWISE, LOOKING FOR SNOW SHOWERS TO LINGER THROUGH TUESDAY AFTERNOON ESPECIALLY ACROSS ALPINE AND MONO COUNTY WHERE UPSLOPE FORCING SETS UP. AN INCH OR TWO IS POSSIBLE ACROSS THE TAHOE BASIN AND MONO COUNTY OUTSIDE OF AREAS OF LAKE ENHANCED SNOWFALL. STRONG WINDS MAY ALSO PRODUCE AREAS OF BLOWING SNOW AND REDUCED VISIBILITY. FUENTES (WEDNESDAY AND THURSDAY).. MAIN CHANGE TO THE WEDNESDAY-THURSDAY TIME FRAME WAS LOWERING MAX AND MIN TEMPS BY A FEW DEGREES EACH, WITH THE INCREASED EXPECTATION OF ACCUMULATING SNOW WITH THE UPPER LOW PASSING THROUGH TONIGHT AND TUESDAY. THE PRESENCE OF SNOW COVER WILL STRENGTHEN THE VALLEY INVERSION FURTHER AND KEEP HIGHS ONLY IN THE LOWER-MID 20S WEDNESDAY. STRONG NE-E WINDS WILL CONTINUE OVER THE SIERRA RIDGES WITH GUSTS 75-85 MPH, WHILE SURFACE WIND GUSTS WILL GENERALLY RANGE FROM 25-35 MPH EXCEPT NEAR 40 MPH AROUND TAHOE WEDNESDAY MORNING. THESE WINDS WILL DECREASE LATER IN THE DAY AS THE UPPER LOW MOVES FROM SOUTHEAST CA TO ARIZONA. NEW YEARS EVE WILL BE QUITE COLD WITH TEMPERATURES BY MIDNIGHT DROPPING TO THE LOWER TEENS FOR RENO-CARSON CITY AND SINGLE DIGITS AROUND TAHOE. ALTHOUGH WINDS WILL BE DECREASING, WIND CHILLS COULD STILL BE NEAR ZERO FOR WESTERN NV AND -10 DEGREES IN THE TAHOE BASIN FOR THE FIRST COUPLE HOURS OF 2015. THE EARLY MORNING LOWS FOR NEW YEARS DAY ARE LIKELY TO BE AROUND 5 DEGREES FOR URBAN AREAS OF WESTERN NV, AND BELOW ZERO AWAY FROM THE MAIN CITIES AND IN THE SIERRA VALLEYS. ON THURSDAY, THE CORE OF THE COLD AIR MASS WILL MOVE AWAY FROM WESTERN NV BUT WITH INVERSION STILL IN PLACE, HIGHS ARE LIKELY TO REMAIN BELOW FREEZING. LIGHTER WINDS ARE EXPECTED WITH DRY CONDITIONS PREVAILING THROUGH THE FIRST DAY OF 2015. MJD LONG TERM (FRIDAY-MONDAY)... THE MOTTO FOR THE LONG TERM WILL BE "WELCOME TO INVERSION CITY". GUIDANCE CONSENSUS SHOWS RIDGING JUST OFF THE WEST COAST THROUGH THE WEEKEND WHICH YIELDS WARMING TEMPERATURES AT 700MB. COUPLED WITH A SURFACE HIGH OVER THE INTERMOUNTAIN WEST THIS RESULTS IN AN INVERSION PATTERN FOR THE VALLEYS OF WESTERN NV AND NORTHEAST CA, WITH LIGHT WINDS, LIMITED MIXING, AND POTENTIAL AIR POLLUTION BUILDUPS. TEMPERATURES IN VALLEYS WILL WARM EACH DAY BUT AT A MUCH SLOWER RATE COMPARED TO THE MOUNTAINS. IF WE GET SUFFICIENT SNOWFALL TONIGHT THEN THOSE INVERSIONS COULD BE STRONGER WITH POTENTIAL FOR SPOTS OF FREEZING FOG IN NORMALLY PRONE AREAS. UNFORTUNATELY I`M REALLY NOT SEEING MEANINGFUL STORM POTENTIAL THROUGH AT LEAST MONDAY AS THE RIDGE BLOCKS PACIFIC STORMS FROM IMPACTING CA/NV. THERE ARE SOME SIGNS OF THE RIDGE BREAKING DOWN OR BEING UNDERCUT MID/LATE NEXT WEEK ALLOWING AN INCREASED CHANCE OF ATMOSPHERIC RIVERS LANDFALLING ON THE WEST COAST. BUT OF COURSE PREDICTABILITY OF THESE PATTERN CHANGES 7-10 DAYS OUT IS QUITE LIMITED. CS AVIATION... FORECAST CONFIDENCE IN TODAY`S TAFS IS MEDIUM, WITH UNCERTAINTIES IN TIMING AND INTENSITY OF TONIGHT`S BAND OF SNOW. THESE KIND OF SLIDER STORMS ARE A CHALLENGE TO PREDICT SO SNOWFALL POTENTIAL REMAINS ONLY MEDIUM CONFIDENCE AS WELL. HIGH RESOLUTION SIMULATIONS (HRRR) ARE SHOWING A FAST MOVING BAND OF -SN DEVELOPING FROM AAT-LOL AROUND SUNDOWN AND THEN DROPPING SOUTHWARD INTO RNO/CXP 4-10Z, TRK/TVL/MEV AROUND 6-12Z, AND AFTER 12Z AT MMH. IN SUCH A STRONGLY FORCED SITUATION THE HRRR USUALLY DOES REASONABLY WELL SO WE`LL FOLLOW FOR THE TAFS. PERIODS OF MVFR/IFR -SN LIKELY AT RNO/CXP/TRK/TVL/MEV TONIGHT YIELDING UP TO 2 INCHES OF FLUFFY SNOW. THERE`S ABOUT A 20% CHANCE WE COULD SEE BRIEF PERIODS OF HEAVIER SNOW, 1/2SM VISIBILITY TYPE STUFF, BUT PREDICTING TIMING ON THAT IS TRICKY. GUSTY N/NE WINDS WILL RESULTING IN BLOWING SNOW AS WELL. CLOUDS WILL RESULT IN TERRAIN OBSCURATION TONIGHT THROUGH TOMORROW. THE POST-FRONTAL NORTHEAST WINDS TUESDAY WILL BE PRONOUNCED AND GUSTY, WITH A FRESH SUSTAINED 15-25 KTS EAST/NORTHEAST WIND WITH GUSTS 25-30 KTS. CXP WHICH IS PRONE TO NE FLOW EVENTS, WILL LIKELY SEE PERIODS OF STRONGER SUSTAINED WINDS. RIDGE LEVEL GUSTS OF 60-70 KTS FORECAST TOMORROW, INCREASING TUESDAY NIGHT INTO WEDNESDAY. DUE TO THE UNUSUAL NE WIND DIRECTION, THAT WILL LEAD TO TURBULENCE ESPECIALLY WEST OF ANY MOUNTAINS DUE TO MOUNTAIN WAVE ACTIVITY. CS && .REV WATCHES/WARNINGS/ADVISORIES... NV...LAKE WIND ADVISORY FROM 7 AM TO 7 PM PST TUESDAY FOR PYRAMID LAKE IN NVZ004. WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY NVZ002. WINTER WEATHER ADVISORY UNTIL 4 PM PST TUESDAY NVZ001. WINTER WEATHER ADVISORY UNTIL 10 AM PST TUESDAY NVZ003. CA...WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY CAZ072. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
919 PM PST MON DEC 29 2014 ...WINDY AND COLDER WEATHER ON THE WAY FOR THE END OF 2014... .SYNOPSIS...A FAST MOVING STORM SYSTEM WILL MOVE SOUTHEAST ACROSS NEVADA TONIGHT BRINGING A SLIGHT CHANCE OF SHOWERS MAINLY IN THE HILLS. COLDER AND WINDIER CONDITIONS WILL SETTLE OVER THE AREA TUESDAY AND WEDNESDAY BEHIND THIS SYSTEM. A WARMING TREND WILL RETURN BY LATE THIS WEEK. && .DISCUSSION...AS OF 9:00 PM PST MONDAY...A COLD UPPER LEVEL LOW OVER SOUTHEAST OREGON WILL DRIVE SOUTHEAST DURING THE NIGHT WITH THE TROUGH AXIS MOVING THROUGH THE AREA LATE TONIGHT. THE SYSTEM HAS VERY LITTLE MOISTURE BUT RECENT HRRR MODEL RUNS HAVE SHOWN ISOLATED CONTOURS OF ONE TO TWO-HUNDREDTHS OF PRECIP IN THE HILLS. A SLIGHT CHANCE OF SHOWERS IS IN THE FORECAST FOR TONIGHT BUT MOST LIKELY ANY PRECIP WILL FALL OVER THE HILLS. WINDS WILL INCREASE AS THIS TROUGH AXIS MOVES THROUGH WITH MODELS SHOWING 925 MB WINDS INCREASING TO 35-45 KT RANGE TUESDAY MORNING. MODELS ALSO SHOW DECENT OMEGA VALUES AFTER THE TROUGH PASSES INDICATING THAT WINDS ALOFT COULD MIX DOWN TO THE SURFACE. THEREFORE A WIND ADVISORY IS IN EFFECT BEGINNING TUESDAY MORNING IN THE NORTH AND EAST BAY HILLS AND SANTA CRUZ MOUNTAINS FOR GUSTS UP TO 55-60 MPH...AND MIDDAY TUESDAY FOR THE REST OF THE SFO BAY AREA WITH GUSTS TO 40-45 MPH. STRONG WINDS WILL CONTINUE THROUGH TUESDAY NIGHT AND MAY EVEN BE SLIGHTLY STRONGER THAN TUESDAY MORNING. THESE STRONG WINDS WILL BRING DOWN SOME TREES AND CAUSE POWER OUTAGES AS THE SOIL REMAINS FAIRLY WET FROM RAINS EARLIER THIS MONTH. WINDS WILL DECREASE BY MIDDAY WEDNESDAY AS THE LOW MOVES FURTHER EAST AND AN UPPER LEVEL RIDGE BUILDS IN FROM THE WEST. COLD NORTHERLY FLOW WILL CONTINUE OVER THE AREA THROUGH WEDNESDAY AND WITH THE WINDS DIMINISHING IT WILL SET UP A COLD NIGHT FOR NEW YEARS EVE. TEMPERATURES WILL DROP INTO THE 20S IN MANY OF THE INLAND VALLEYS WITH LOWER TO MID 30S IN THE URBAN AREAS AROUND OAKLAND-SAN JOSE. A FROST ADVISORY MAY BE NEEDED FOR MOST OF THE SFO BAY AREA WEDNESDAY NIGHT. TEMPERATURES WILL SLOWLY WARM UP THURSDAY THROUGH SUNDAY AS THE UPPER LEVEL RIDGE MOVES OVER THE WEST COAST. IN THE LONG RANGE...MODELS CONTINUE TO STRUGGLE WITH WHETHER THERE WILL BE RAIN IN OUR CWA AROUND THE MIDDLE OF NEXT WEEK. LATEST GFS AND ECMWF INDICATE A CHANCE FOR RAIN FOR AT LEAST THE NORTHERN PART OF THE DISTRICT. && .AVIATION...AS OF 4:45 PM PST MONDAY...PATCHES OF LOW AND MID LEVEL CLOUDINESS REMAIN OVER PORTIONS OF THE DISTRICT BUT WITH ALL TERMINALS NOW REPORTING VFR CONDITIONS. THESE SHOULD CONTINUE THROUGH THE NIGHT AS THE BOUNDARY LAYER AIR MASS LOOKS TO REMAIN SUFFICIENTLY DRY AND WELL MIXED AS TO PRECLUDE DEVELOPMENT OF EITHER FOG OR CIGS. THE PASSAGE OF A STRONG BUT DRY UPPER LEVEL DISTURBANCE FROM THE NORTH TONIGHT...IN CONJUNCTION WITH DEVELOPMENT OF A STRONG NE TO SW ORIENTED SEA LEVEL PRESSURE GRADIENT...WILL RESULT IN INCREASINGLY STRONG NORTH TO NORTHEASTERLY FLOW ALOFT OVER THE AREA. KEY QUESTIONS ARE WHEN...WHERE...AND TO WHAT DEGREE THESE WINDS MIX DOWN TO THE SURFACE. HIGH RESOLUTION LOCAL MODEL OUTPUT INDICATES THIS WILL PROGRESSIVELY OCCUR AT SFO BAY AREA TAF SITES DURING THE DAY ON TUESDAY...WITH WINDS POTENTIALLY BECOMING LOCALLY STRONG AND GUSTY BY AFTERNOON. VICINITY OF KSFO...NO MORE THAN SCATTERED CLOUDINESS IS EXPECTED OVERNIGHT AND TUESDAY MORNING AS THE AIR MASS REMAINS DRY AND WELL MIXED. WINDS VEER NORTH-NORTHEASTERLY TOMORROW AND ARE LIKELY TO BECOME STRONG AND GUSTY BY AFTERNOON. MEDIUM CONFIDENCE. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WITH GENERALLY LIGHT WINDS THROUGH THE PERIOD. MEDIUM CONFIDENCE. && .MARINE...AS OF 01:38 PM PST MONDAY...STRONG HIGH PRESSURE WILL BUILD OVER THE GREAT BASIN INCREASING NORTHERLY WINDS THROUGH WEDNESDAY. WINDS DECREASE WEDNESDAY NIGHT AND THURSDAY AS THE HIGH WEAKENS. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PT REYES TO PIGEON PT 10-60 NM SCA...PT ARENA TO PT REYES 0-10 NM SCA...PT ARENA TO PT REYES 10-60 NM SCA...PIGEON PT TO PT PINOS 10-60 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PIGEON PT TO PT PINOS 0-10 NM && $$ PUBLIC FORECAST: W PI AVIATION: BLIER MARINE: AC VISIT US AT WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
409 AM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TODAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP SATURDAY AND LIFT NORTH OF THE REGION BY SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THROUGH SUNRISE...STRATUS BUILD DOWN IS IN PROGRESS WITH BKN-OVC CLOUDY LAYERS OF 100-300 FT BEGINNING TO LOWER TO THE SURFACE. ALREADY SEEING A FEW SITES WITH VISIBILITIES LESS THAN 1/2 MILE AND TRENDS ARE BEING WATCHED FOR THE DEVELOPMENT OF DENSE FOG. VSBYS AND WEBCAMS IN THE BEAUFORT AND SAVANNAH AREAS INDICATE THE FOG IS QUICKLY BECOMING DENSE AND WIDESPREAD ENOUGH FOR A DENSE FOG ADVISORY. AN ADVISORY HAS BE ISSUED FOR COASTAL COLLETON-BEAUFORT- INLAND JASPER-COASTAL JASPER-INLAND CHATHAM AND COASTAL CHATHAM UNTIL 9 AM. IT IS UNCLEAR HOW WIDESPREAD THE DENSE FOG WILL BECOME ELSEWHERE...ESPECIALLY GIVEN WINDS ARE AVERAGING 5-10 MPH...BUT THE ADVISORY WILL BE ADJUSTED TEMPORALLY OR SPATIALLY AS NEEDED. TODAY...LOW CONFIDENCE FORECAST TODAY. THE COLD FRONT AND ASSOCIATED FRONTAL WAVE ARE NOW WELL OFFSHORE WITH A NORTHERLY LOW-LEVEL FLOW DOMINATING IN ITS WAKE. A WEAK POST FRONTAL SURFACE TROUGH DELINEATING A SURGE OF COOLER AIR WILL APPROACH THE CHARLESTON AREA BY SUNRISE...THE SAVANNAH AREA BY MID-MORNING AND FINALLY CLEARING THE ALTAMAHA RIVER BY LATE AFTERNOON. MODELS SHOW A TRANSIENT HYBRID WEDGE SETTING UP ACROSS MAINLY THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA IN THE WAKE OF THE TROUGH AS 290K ISENTROPIC ASSENT BRIEFLY INTENSIFIES ATOP THE LOW-LEVEL POST FRONTAL WEDGING PATTERN. THIS PATTERN WILL ESSENTIALLY REINFORCE THE WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE THAT ARE ALREADY IN PLACE ACROSS THE LOWCOUNTRY AND COASTAL EMPIRE FOR A GOOD PORTION OF THE DAY. THE TEMPERATURE FORECAST IS PROVING TO BE EXTREMELY CHALLENGING AS A RESULT AND ASSUMES THE TRANSIENT WEDGE ACTUALLY DEVELOPS AS DEPICTED IN THE HIGHER RESOLUTION DATA SETS. DAILY HIGHS /7AM-6PM/ WILL LIKELY OCCUR BY MID-MORNING ACROSS THE CHARLESTON TRI-COUNTY AREA AND EARLY AFTERNOON ACROSS THE REMAINDER OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. TEMPERATURES WILL LIKELY HOLD STEADY OR SLOWLY FALL NORTH THE SAVANNAH RIVER AS THE WEDGE BRIEFING INTENSIFIES. HIGHS WILL RANGE MID 50S NORTH...UPPER 50/NEAR 60 CENTRAL TO THE LOWER-MID 60S SOUTH. UTILIZE A 30/30/30 BLEND OF RAP/H3R AND GLAMP DATA TO CONSTRUCT HOURLY TEMPERATURES. SINCE THIS IS A VERY LOW CONFIDENCE FORECAST...CHANGES--SOME POSSIBLY SIGNIFICANT--WILL LIKELY BE NEEDED THROUGHOUT THE DAY. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... TONIGHT...THE TRANSIENT HYBRID WEDGE WILL QUICKLY BREAKDOWN THIS EVENING AS HIGH PRESSURE FINALLY BRIDGES THE SOUTHERN APPALACHIANS AND BECOMES MORE DOMINATE ACROSS THE SOUTHEAST STATES. A GOOD BIT OF CLOUD COVER WILL LINGER THROUGH THE NIGHT WITH THE POTENTIAL FOR SOME CLEARING TO OCCUR ACROSS THE NORTH AFTER 3 AM. WILL HAVE TO WATCH FOR SOME FOG TO DEVELOP AFTER MIDNIGHT...BUT THIS DOES NOT LOOK SIGNIFICANT AT THIS TIME. LOWS WILL RANGE FROM THE MID- UPPER 30S INTERIOR NORTH WHERE THE BETTER CHANCES FOR CLEARING WILL OCCUR WITH UPPER 30S TO LOWER 40S ELSEWHERE...EXCEPT MID 40S ALONG THE GEORGIA COAST WHERE ONSHORE WINDS WILL MODERATE TEMPERATURES A BIT. WEDNESDAY AND THURSDAY...EXPANSIVE SURFACE HIGH PRESSURE WILL BE GRADUALLY WEAKENING AS IT SLIPS TOWARD THE EAST COAST UNDER RELATIVELY ZONAL FLOW ALOFT. EXPECT DRY CONDITIONS TO PREVAIL WEDNESDAY AND THURSDAY WITHIN THIS PATTERN. TEMPERATURES WEDNESDAY WILL BE A FEW DEGREES COOLER THAN NORMAL...PEAKING IN THE MID TO UPPER 50S DURING THE AFTERNOON AND FALLING INTO THE LOW 30S NORTH TO UPPER 30S COAST AND SOUTH OVERNIGHT. NORTH FLOW WEAKENS ON THURSDAY AS THE CENTER OF THE SURFACE HIGH PASSES DIRECTLY OVER THE REGION...AND WITH SUBTLE RIDGING BUILDING UP FROM THE BAHAMAS...HIGH TEMPERATURES WILL MODERATE TOWARD SEASONAL NORMALS IN THE UPPER 50S TO LOWER 60S. A GRADUALLY IMPROVING TAP INTO GULF MOISTURE LATE THURSDAY WILL SUPPORT INCREASING CLOUDS...WITH LOW TEMPERATURES A FEW DEGREES MILDER IN THE UPPER 30S INLAND TO LOW 40S CLOSER TO THE COAST. FRIDAY...AN UPPER LEVEL CUT OFF LOW WILL MOVE FROM THE SOUTHWEST STATES INTO THE SOUTHERN PLAINS...PROVIDING THE ENERGY TO DEVELOP A WAVE OF LOW PRESSURE ACROSS THE WESTERN GULF LATE IN THE DAY. THE SOUTHEAST STATES WILL REMAIN ON THE PERIPHERY OF ATLANTIC HIGH PRESSURE...WHERE SHORTWAVE ENERGY TRACKING UP FROM THE GULF OF MEXICO WILL SUPPORT THE GRADUAL AMPLIFICATION OF A COASTAL TROUGH. NUMERICAL MODEL SOLUTIONS ARE INDICATING SUFFICIENT ISENTROPIC ASCENT BETWEEN THE COASTAL TROUGH AND A DEVELOPING INLAND WEDGE TO GENERATE ISOLATED TO SCATTERED RAIN...WITH BEST COVERAGE ACROSS NORTHERN AND INLAND AREAS. TEMPERATURES COULD BE A DEGREE OR TWO COOLER THAN THE PREVIOUS DAY GIVEN THE INCREASING CLOUD COVER...YET STILL RANGE NEAR SEASONAL NORMALS IN THE UPPER 50S TO LOW 60S. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... FRIDAY NIGHT THROUGH SUNDAY...A TRANSIENT INLAND WEDGE/COASTAL TROUGH PATTERN WILL BE IN PLACE THROUGH EARLY SATURDAY...BEFORE THE COASTAL TROUGH QUICKLY LIFTS NORTH OF THE REGION AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. THE CUT OFF LOW ACROSS THE SOUTHERN PLAINS WILL DAMPEN AND LIFT NORTHEAST INTO THE OHIO VALLEY ON SATURDAY. THE ASSOCIATED SURFACE LOW WILL PULL INTO THE NEW ENGLAND STATES SUNDAY...WITH ITS TRAILING COLD FRONT PROGRESSING THROUGH THE MID ATLANTIC AND SOUTHEAST STATES BY SUNDAY AFTERNOON. HIGH TEMPERATURES WILL SURGE INTO THE 60S TO AROUND 70 DEGREES SATURDAY AND SUNDAY WITHIN WARM SOUTHERLY FLOW AHEAD OF THE FRONT...WHILE SCATTERED SHOWERS ARE POSSIBLE SATURDAY THROUGH SUNDAY AFTERNOON. PREFER TO REMAIN RATHER CONSERVATIVE WITH RAIN CHANCES AT THIS POINT...CONSIDERING THE SOUTHERN END OF THE FRONT WILL RUN INTO THE PERIPHERY OF THE SUBTROPICAL RIDGE AND BECOME PARALLEL TO FLOW ALOFT. SUNDAY NIGHT THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BUILD IN THE WAKE OF THE DEPARTING COLD FRONT EARLY NEXT WEEK...EVENTUALLY SETTLING TO THE NORTH OF THE AREA. RAIN FREE CONDITIONS WILL PREVAIL. TEMPERATURES ARE EXPECTED TO RETURN TO SEASONAL NORMALS...POSSIBLY COOLER IF A WEDGE PATTERN CAN SET UP TOWARD THE END OF THE FORECAST PERIOD. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... LIFR CIGS WILL LINGER AT BOTH TERMINALS THROUGH SUNRISE. CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS AND COULD DROP BELOW AIRPORT MINIMUMS OVER THE NEXT FEW HOURS. FOG COULD BECOME A PROBLEM LATE...BUT THE LOW CIGS WILL BE THE PRIMARY ISSUE UNLESS THE STRATUS DECKS REACH THE GROUND RESULTING IN DENSE FOG. LOW CONFIDENCE IN THIS SCENARIO RIGHT NOW. CIGS WILL LIFT EVER SO SLOWLY AFTER SUNRISE...BUT SHOULD RISE ABOVE ALTERNATE MINIMUMS 13-14Z...ALTHOUGH STAYING IN IFR. MVFR SHOULD RETURN BY 16-17Z AND LINGER THE REST OF THE 06Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL WEDNESDAY AND THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TODAY...CEILINGS OF 100 FT AT THE HILTON HEAD AIRPORT AND WEBCAMS IN THE SAVANNAH RIVER AS WELL AS TYBEE ISLAND SUGGEST SEA FOG IS IN PLACE ACROSS THE COASTAL WATERS THIS MORNING. IT IS UNCLEAR EXACTLY HOW WIDESPREAD THE FOG IS...BUT RAP VISIBILITIES DATA SUGGEST ITS PROBABLY PRETTY WIDESPREAD. WFO JAX RECENTLY RELAYED THAT THE BAR PILOTS OUT OF SAINT SIMMONS ARE REPORTING IMPROVED VSBYS OVER THE PAST HOUR...BUT THE SHELF WATERS OFF TYBEE ISLAND ARE SEVERAL DEGREES COOLER. PREFER TO HOLD THE MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE AND BEAUFORT COUNTY WATERS UNTIL 8 AM...OR AT LEAST UNTIL CONDITIONS CAN BE BETTER EVALUATED ON COASTAL WEBCAMS AS THE SUN RISES. OTHERWISE...NORTH WINDS WILL INCREASE TO 10-15 KT TODAY WITH SEAS 1-3 FT. TONIGHT...WINDS WILL INCREASE A BIT AS THE PRESSURE GRADIENT INDUCED BY HIGH PRESSURE BUILDING IN FROM THE WEST TIGHTENS. EXPECT WINDS OF 15-20 KT WITH SEAS 2-3 FT NEARSHORE...4-5 FT OFFSHORE. WEDNESDAY THROUGH SATURDAY...THE PRESSURE GRADIENT WILL REMAIN RELATIVELY TIGHT INTO WEDNESDAY MORNING ON THE PERIPHERY OF HIGH PRESSURE BUILDING FROM THE WEST. MARGINAL SMALL CRAFT ADVISORY WINDS IN GUSTS TO 25 KT COULD LINGER ACROSS THE OFFSHORE GEORGIA WATERS...BEFORE CONDITIONS SLOWLY IMPROVE AS THE DAY PROGRESSES. THE SURFACE HIGH WILL THEN STEADILY TRACK EAST AND ALLOW THE GRADIENT TO RELAX TOWARD THE END OF THE WEEK. A COASTAL TROUGH WILL DEVELOP LATE FRIDAY INTO SATURDAY...WITH INCREASING SOUTHERLY FLOW IN IT WAKE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR GAZ118-119. SC...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR SCZ047>049- 051. MARINE...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR AMZ352-354. && $$ ST/WMS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
129 AM EST TUE DEC 30 2014 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTHEAST INTO THE ATLANTIC EARLY TONIGHT AND PUSH FURTHER OFFSHORE OVERNIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP EARLY THIS WEEKEND THEN LIFT NORTH OF THE REGION ON SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... WEAK COLD FRONT HAS CLEARED THE GEORGIA COAST WITH A PRONOUNCED POST-FRONTAL SURFACE TROUGH DROPPING SOUTH. THE TROUGH HAS PASSED THE CHARLESTON AIRPORT AND WILL CONTINUE TO MOVE SLOWLY SOUTH THROUGH SUNRISE. LOW STRATUS AND EVENTUALLY FOG WILL AFFECT THE REGION OVERNIGHT WITH OCCASIONAL LIGHT DRIZZLE. SKIES HAVE CLEARED BRIEFLY ACROSS ALLENDALE COUNTY AND DENSE RADIATION FOG HAS QUICKLY DEVELOPED. ITS UNCLEAR HOW LONG THE DENSE FOG WILL LAST...BUT IT MAY BE ANOTHER 1-2 HOURS BEFORE LOW CLOUDS FILL IN FROM THE NORTH. IN FACT...CLEARING AND DENSE FOG COULD OCCUR ACROSS MUCH OF THE FAR WESTERN ZONES FOR THE NEXT FEW HOURS. WILL WATCH TRENDS CAREFULLY. OTHERWISE...DRIZZLE AND EXTENSIVE CLOUD COVER WILL PERSIST. IT IS UNCLEAR HOW STRONG POST-FRONTAL STRATUS BUILD DOWN WILL BE...BUT THERE IS A POTENTIAL FOR SOME DENSE FOG. MADE ADJUSTMENTS TO CLOUD COVER...FOG COVERAGE AND INTRODUCED AREAS OF DRIZZLE INTO THE FORECAST FOR THE MIDNIGHT UPDATE. THE REST OF THE FORECAST IS OKAY. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... TUESDAY AND TUESDAY NIGHT...NEARLY ZONAL FLOW WILL PREVAIL ALOFT AS A COLD FRONT SLIPS OFF SHORE. BACK TO THE WEST...CONFLUENT FLOW ALOFT WILL HELP TO FORCE AN IMPRESSIVE 1058 MB HIGH OVER THE NORTHERN ROCKIES THAT WILL BUILD INTO THE FORECAST AREA THROUGH THE DAY. FOLLOWING LOW LEVEL THETA E FIELDS...THE LEADING EDGE OF THE COOLER AIR BEHIND THE FRONT AND THE EXTENT OF THE STRONG SURFACE HIGH WILL NOT OOZE INTO THE AREA UNTIL LATER IN THE DAY ON TUESDAY AND POSSIBLY EVEN INTO THE EVENING. AHEAD OF THIS THETA E GRADIENT...RESIDUAL MOISTURE IN THE LOWEST 3-4K FT OF THE ATMOSPHERE SHOWS UP WELL IN MODEL TIME HEIGHTS AND CROSS SECTIONS. THIS SHOULD MANIFEST ITSELF IN THE FORM OF EXTENSIVE STRATUS ACROSS THE FORECAST AREA FOR MUCH OF THE DAY. IN FACT...WE MAY NOT SEE ANY CLEARING IN THE TRI-COUNTY REGION UNTIL LATE IN THE AFTERNOON. THIS WILL HELP KEEP TEMPERATURES AT BAY DESPITE THE LATER ARRIVAL OF THE COOLER AIR. LOOK FOR HIGHS IN THE MID/UPPER 50S FURTHER NORTH...AND LOW 60S FURTHER TO THE SOUTH. SOME OF THE MODELS ARE WRINGING OUT SOME MEASURABLE PRECIPITATION IN THE MORNING DESPITE THE LACK OF FORCING AND RELATIVELY SHALLOW MOIST LAYER. HAVE KEPT THE FORECAST DRY. OVERNIGHT...COOL NORTHERLY FLOW WILL SETTLE IN AS THE LOW LEVELS START TO DRY OUT. THE FORECAST IS DRY AND FEATURES LOWS FALLING INTO THE UPPER 30S NORTH...LOW 40S FURTHER SOUTH FOR COASTAL SOUTHEAST GEORGIA. WEDNESDAY THROUGH THURSDAY...ZONAL FLOW WILL PREVAIL ALOFT AS EXPANSIVE BUT WEAKENING HIGH PRESSURE BUILDS IN FROM THE WEST. WE MAY BE DEALING WITH A DECENT AMOUNT OF JET-INDUCED HIGH CLOUDS ON WEDNESDAY...BUT A COLUMN THAT IS OVERALL VERY DRY WILL KEEP THE FORECAST RAIN FREE THROUGH THURSDAY. TEMPERATURES WILL BE ON THE COOL SIDE WEDNESDAY...RUNNING ABOUT 4 DEGREES BELOW NORMAL...THEN RIGHT AROUND NORMAL ON THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... THE EXPANSIVE SURFACE HIGH WILL STEADILY SHIFT OVER GEORGIA AND THE CAROLINAS BY FRIDAY...BEFORE MOVING INTO THE ATLANTIC WATERS SATURDAY. A STRONG CUT OFF LOW OVER THE DESERT SOUTHWEST FRIDAY WILL EJECT INTO THE SOUTHERN PLAINS OVER THE WEEKEND AND THEN DAMPEN AS IT MOVE INTO THE UPPER GULF COAST REGION BY LATE WEEKEND. CLOUDS WILL BE ON THE INCREASE THURSDAY NIGHT AS A SHORT WAVES TRAVERSES INTO THE REGION ATOP A LARGE SUBTROPICAL RIDGE OVER FLORIDA AND THE CARIBBEAN. THIS DISTURBANCE MAY PRODUCE SOME SPOTTY LIGHT RAINS ON FRIDAY BUT CERTAINLY NOT SIGNIFICANT AS PRECIP IS LIKELY TO EVAPORATE IN DRY LAYERS BELOW 10 KFT. A SLIGHT CHANCE POP LOOKS QUITE SUFFICIENT. STEADIER RAINS ACROSS NORTH GEORGIA AND THE WESTERN CAROLINAS MAY BEGIN TO ANCHOR A WEDGE ON SATURDAY WITH GLOBAL MODELS DIFFERING ON SURFACE PATTERNS. THE WEEKEND LOOKS A BIT UNSETTLED WITH PLENTY OF CLOUDS MOST AREAS AND MAINLY LOW END CHANCE POPS AS THE UPPER WAVE FLATTENS SIGNIFICANTLY LATE IN THE WEEKEND. SUNDAY APPEARS TO BE THE WARMER OF THE DAYS AFTER WE TRENDED DOWN A GOOD BIT ON TEMPS NORTHERN ZONES SATURDAY. A COLD FRONT SHOULD MOVE OFF THE COAST EARLY NEXT WEEK. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... LIFR CIGS WILL LINGER AT BOTH TERMINALS THROUGH SUNRISE. CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS AND COULD DROP BELOW AIRPORT MINIMUMS OVER THE NEXT FEW HOURS. FOG COULD BECOME A PROBLEM LATE...BUT THE LOW CIGS WILL BE THE PRIMARY ISSUE UNLESS THE STRATUS DECKS REACH THE GROUND RESULTING IN DENSE FOG. LOW CONFIDENCE IN THIS SCENARIO RIGHT NOW. CIGS WILL LIFT EVER SO SLOWLY AFTER SUNRISE...BUT SHOULD RISE ABOVE ALTERNATE MINIMUMS 13-14Z...ALTHOUGH STAYING IN IFR. MVFR SHOULD RETURN BY 16-17Z AND LINGER THE REST OF THE 06Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...LOW CEILINGS TO CLEAR OUT TUESDAY NIGHT...IF NOT BEFORE. VFR CONDITIONS WILL THEN PREVAIL THROUGH AT LEAST THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TONIGHT...CEILINGS AT HILTON HEAD HAVE DROPPED TO 100 FT... SUGGESTING DENSE FOG IN OCCURRING JUST OFFSHORE. EXPANDED THE MARINE DENSE FOG ADVISORY NORTH TO INCLUDE THE BEAUFORT COUNTY WATERS. WEBCAMS OUT OF TYBEE ISLAND AND EARLIER REPORTS FROM THE SAINT SIMMONS BAR PILOT BOAT PROVIDE ENOUGH DATA TO SUPPORT A MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE WATERS THROUGH 6 AM. RAP VSBY PROGS APPEAR TO CAPTURE THE SEA FOG WELL AND WAS USED TO CONSTRUCT WEATHER AND VSBY GRIDS THROUGH 6 AM. TUESDAY THROUGH SATURDAY...A COLD FRONT WILL PUSH WELL OFFSHORE TUESDAY AS HIGH PRESSURE WILL BEGIN TO BUILD IN TUESDAY NIGHT. AS THE HIGH BUILDS IN A NOTABLE NORTHERLY SURGE WILL TAKE PLACE TUESDAY NIGHT AND INTO WEDNESDAY MORNING. A SOLID 15-20 KT OF WIND IS EXPECTED WITHIN 20 NM WITH SOME GUSTS TO 25 KT POSSIBLE. WINDS WILL BE CLOSER TO 20-25 KT FOR THE OUTER GEORGIA WATERS WITH SOME 6 FT SEAS POSSIBLE. SMALL CRAFT ADVISORIES MAY BE NEEDED...ESPECIALLY FOR THE OUTER GEORGIA WATERS TUESDAY NIGHT. THEREAFTER...HIGH PRESSURE WILL BE THE PRIMARY WEATHER FEATURE THOUGH THE GRADIENT WILL RELAX. IT IS STILL A BIT TOO EARLY TO COMMIT ON STRENGTH OF THE WEDGE THIS WEEKEND AND TIMING THE WARM FRONT THROUGH...BUT COMPLEX LOW LEVEL MIXING ENVIRONMENTS ARE LIKELY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR AMZ352-354. && $$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1240 AM EST TUE DEC 30 2014 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTHEAST INTO THE ATLANTIC EARLY TONIGHT AND PUSH FURTHER OFFSHORE OVERNIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP EARLY THIS WEEKEND THEN LIFT NORTH OF THE REGION ON SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... WEAK COLD FRONT HAS CLEARED THE GEORGIA COAST WITH A PRONOUNCED POST-FRONTAL SURFACE TROUGH DROPPING SOUTH. THE TROUGH HAS PASSED THE CHARLESTON AIRPORT AND WILL CONTINUE TO MOVE SLOWLY SOUTH THROUGH SUNRISE. LOW STRATUS AND EVENTUALLY FOG WILL AFFECT THE REGION OVERNIGHT WITH OCCASIONAL LIGHT DRIZZLE. SKIES HAVE CLEARED BRIEFLY ACROSS ALLENDALE COUNTY AND DENSE RADIATION FOG HAS QUICKLY DEVELOPED. ITS UNCLEAR HOW LONG THE DENSE FOG WILL LAST...BUT IT MAY BE ANOTHER 1-2 HOURS BEFORE LOW CLOUDS FILL IN FROM THE NORTH. IN FACT...CLEARING AND DENSE FOG COULD OCCUR ACROSS MUCH OF THE FAR WESTERN ZONES FOR THE NEXT FEW HOURS. WILL WATCH TRENDS CAREFULLY. OTHERWISE...DRIZZLE AND EXTENSIVE CLOUD COVER WILL PERSIST. IT IS UNCLEAR HOW STRONG POST-FRONTAL STRATUS BUILD DOWN WILL BE...BUT THERE IS A POTENTIAL FOR SOME DENSE FOG. MADE ADJUSTMENTS TO CLOUD COVER...FOG COVERAGE AND INTRODUCED AREAS OF DRIZZLE INTO THE FORECAST FOR THE MIDNIGHT UPDATE. THE REST OF THE FORECAST IS OKAY. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... TUESDAY AND TUESDAY NIGHT...NEARLY ZONAL FLOW WILL PREVAIL ALOFT AS A COLD FRONT SLIPS OFF SHORE. BACK TO THE WEST...CONFLUENT FLOW ALOFT WILL HELP TO FORCE AN IMPRESSIVE 1058 MB HIGH OVER THE NORTHERN ROCKIES THAT WILL BUILD INTO THE FORECAST AREA THROUGH THE DAY. FOLLOWING LOW LEVEL THETA E FIELDS...THE LEADING EDGE OF THE COOLER AIR BEHIND THE FRONT AND THE EXTENT OF THE STRONG SURFACE HIGH WILL NOT OOZE INTO THE AREA UNTIL LATER IN THE DAY ON TUESDAY AND POSSIBLY EVEN INTO THE EVENING. AHEAD OF THIS THETA E GRADIENT...RESIDUAL MOISTURE IN THE LOWEST 3-4K FT OF THE ATMOSPHERE SHOWS UP WELL IN MODEL TIME HEIGHTS AND CROSS SECTIONS. THIS SHOULD MANIFEST ITSELF IN THE FORM OF EXTENSIVE STRATUS ACROSS THE FORECAST AREA FOR MUCH OF THE DAY. IN FACT...WE MAY NOT SEE ANY CLEARING IN THE TRI-COUNTY REGION UNTIL LATE IN THE AFTERNOON. THIS WILL HELP KEEP TEMPERATURES AT BAY DESPITE THE LATER ARRIVAL OF THE COOLER AIR. LOOK FOR HIGHS IN THE MID/UPPER 50S FURTHER NORTH...AND LOW 60S FURTHER TO THE SOUTH. SOME OF THE MODELS ARE WRINGING OUT SOME MEASURABLE PRECIPITATION IN THE MORNING DESPITE THE LACK OF FORCING AND RELATIVELY SHALLOW MOIST LAYER. HAVE KEPT THE FORECAST DRY. OVERNIGHT...COOL NORTHERLY FLOW WILL SETTLE IN AS THE LOW LEVELS START TO DRY OUT. THE FORECAST IS DRY AND FEATURES LOWS FALLING INTO THE UPPER 30S NORTH...LOW 40S FURTHER SOUTH FOR COASTAL SOUTHEAST GEORGIA. WEDNESDAY THROUGH THURSDAY...ZONAL FLOW WILL PREVAIL ALOFT AS EXPANSIVE BUT WEAKENING HIGH PRESSURE BUILDS IN FROM THE WEST. WE MAY BE DEALING WITH A DECENT AMOUNT OF JET-INDUCED HIGH CLOUDS ON WEDNESDAY...BUT A COLUMN THAT IS OVERALL VERY DRY WILL KEEP THE FORECAST RAIN FREE THROUGH THURSDAY. TEMPERATURES WILL BE ON THE COOL SIDE WEDNESDAY...RUNNING ABOUT 4 DEGREES BELOW NORMAL...THEN RIGHT AROUND NORMAL ON THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... THE EXPANSIVE SURFACE HIGH WILL STEADILY SHIFT OVER GEORGIA AND THE CAROLINAS BY FRIDAY...BEFORE MOVING INTO THE ATLANTIC WATERS SATURDAY. A STRONG CUT OFF LOW OVER THE DESERT SOUTHWEST FRIDAY WILL EJECT INTO THE SOUTHERN PLAINS OVER THE WEEKEND AND THEN DAMPEN AS IT MOVE INTO THE UPPER GULF COAST REGION BY LATE WEEKEND. CLOUDS WILL BE ON THE INCREASE THURSDAY NIGHT AS A SHORT WAVES TRAVERSES INTO THE REGION ATOP A LARGE SUBTROPICAL RIDGE OVER FLORIDA AND THE CARIBBEAN. THIS DISTURBANCE MAY PRODUCE SOME SPOTTY LIGHT RAINS ON FRIDAY BUT CERTAINLY NOT SIGNIFICANT AS PRECIP IS LIKELY TO EVAPORATE IN DRY LAYERS BELOW 10 KFT. A SLIGHT CHANCE POP LOOKS QUITE SUFFICIENT. STEADIER RAINS ACROSS NORTH GEORGIA AND THE WESTERN CAROLINAS MAY BEGIN TO ANCHOR A WEDGE ON SATURDAY WITH GLOBAL MODELS DIFFERING ON SURFACE PATTERNS. THE WEEKEND LOOKS A BIT UNSETTLED WITH PLENTY OF CLOUDS MOST AREAS AND MAINLY LOW END CHANCE POPS AS THE UPPER WAVE FLATTENS SIGNIFICANTLY LATE IN THE WEEKEND. SUNDAY APPEARS TO BE THE WARMER OF THE DAYS AFTER WE TRENDED DOWN A GOOD BIT ON TEMPS NORTHERN ZONES SATURDAY. A COLD FRONT SHOULD MOVE OFF THE COAST EARLY NEXT WEEK. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... LIFR CIGS WILL LINGER AT BOTH TERMINALS THROUGH SUNRISE. CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS AND COULD DROP BELOW AIRPORT MINIMUMS OVER THE NEXT FEW HOURS. FOG COULD BECOME A PROBLEM LATE...BUT THE LOW CIGS WILL BE THE PRIMARY ISSUE UNLESS THE STRATUS DECKS REACH THE GROUND RESULTING IN DENSE FOG. LOW CONFIDENCE IN THIS SCENARIO RIGHT NOW. CIGS WILL LIFT EVER SO SLOWLY AFTER SUNRISE...BUT SHOULD RISE ABOVE ALTERNATE MINIMUMS 13-14Z...ALTHOUGH STAYING IN IFR. MVFR SHOULD RETURN BY 16-17Z AND LINGER THE REST OF THE 06Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...LOW CEILINGS TO CLEAR OUT TUESDAY NIGHT...IF NOT BEFORE. VFR CONDITIONS WILL THEN PREVAIL THROUGH AT LEAST THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TONIGHT...WEBCAMS OUT OF TYBEE ISLAND AND EARLIER REPORTS FROM THE SAINT SIMMONS BAR PILOT BOAT PROVIDE ENOUGH DATA TO SUPPORT A MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE WATERS THROUGH 6 AM. RAP VSBY PROGS APPEAR TO CAPTURE THE SEA FOG WELL AND WAS USED TO CONSTRUCT WEATHER AND VSBY GRIDS THROUGH 6 AM. TUESDAY THROUGH SATURDAY...A COLD FRONT WILL PUSH WELL OFFSHORE TUESDAY AS HIGH PRESSURE WILL BEGIN TO BUILD IN TUESDAY NIGHT. AS THE HIGH BUILDS IN A NOTABLE NORTHERLY SURGE WILL TAKE PLACE TUESDAY NIGHT AND INTO WEDNESDAY MORNING. A SOLID 15-20 KT OF WIND IS EXPECTED WITHIN 20 NM WITH SOME GUSTS TO 25 KT POSSIBLE. WINDS WILL BE CLOSER TO 20-25 KT FOR THE OUTER GEORGIA WATERS WITH SOME 6 FT SEAS POSSIBLE. SMALL CRAFT ADVISORIES MAY BE NEEDED...ESPECIALLY FOR THE OUTER GEORGIA WATERS TUESDAY NIGHT. THEREAFTER...HIGH PRESSURE WILL BE THE PRIMARY WEATHER FEATURE THOUGH THE GRADIENT WILL RELAX. IT IS STILL A BIT TOO EARLY TO COMMIT ON STRENGTH OF THE WEDGE THIS WEEKEND AND TIMING THE WARM FRONT THROUGH...BUT COMPLEX LOW LEVEL MIXING ENVIRONMENTS ARE LIKELY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR AMZ354. && $$ ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 AM CST TUE DEC 30 2014 .SHORT TERM... 229 AM CST THROUGH WEDNESDAY... ONE WORD SUMS UP THE ENTIRE SHORT TERM FORECAST: COLD. SOMEWHAT MODIFIED ARCTIC AIR IS SEEPING SOUTH AND SHOULD SET THE STAGE FOR SEASONABLY COLD CONDITIONS THE NEXT COUPLE DAYS. THE LACK OF SNOW COVER HERE OR IMMEDIATELY UPSTREAM SHOULD ALLOW THE AIR MASS TO MODIFY SOME AND WE CERTAINLY WILL NOT BE ANYWHERE NEAR AS COLD AS IT WOULD BE WITH SNOW COVER. STRONG LOW PRESSURE WILL DROP SOUTH INTO HUDSON BAY WEDNESDAY AND WE COMBINED WITH THE STRONG HIGH TO OUR SOUTH WILL SET THE STAGE FOR AN INCREASINGLY WINDY DAY WEDNESDAY...SO EVEN THOUGH TEMPERATURES WILL BE IN THE SAME BALLPARK AS TODAY ON WEDNESDAY THE STRONG WINDS WILL MAKE IT FEEL COLDER WITH WIND CHILLS HOVERING NEAR ZERO OR EVEN A BIT BELOW ALL DAY AND INTO NEW YEARS EVE NIGHT. IZZI && .LONG TERM... 229 AM CST WEDNESDAY NIGHT THROUGH MONDAY... TROUGH OVER THE REGION WILL RETREAT WITH RISING HEIGHTS AND MODERATING TEMPERATURES THURSDAY AND FRIDAY WITH GENERALLY DRY CONDITIONS. IN THE LONGER TERM ALL EYES WILL BE ON WHAT BECOMES OF THE POWERFUL CUT OFF SYSTEM OVER THE SOUTHWEST. MEDIUM RANGE MODELS CONTINUE TO WAFFLE AROUND WITH TIMING...TRACK...AND INTENSITY VARYING FROM RUN TO RUN AND MODEL TO MODEL. THESE TYPE OF SYSTEMS ARE NOT WELL HANDLED BY NUMERICAL GUIDANCE AND WOULD EXPECT CONTINUE MODEL VARIANCES...SOME POSSIBLY SIGNIFICANT...IN THE COMING DAYS SO AM NOT WILLING TO STRAY FROM THE BLENDED MODEL GUIDANCE WITH LOW POPS AND RAIN OR SNOW FOR P-TYPE. DOES LOOK LIKE MORE COLD AIR WILL PROBABLY SPILL INTO THE AREA BEHIND THAT SOUTHWESTERN SYSTEM WHEN EVER IT DOES END UP PASSING BY. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * NORTH-NORTHWEST WINDS 10 KT OR HIGHER GRADUALLY SHIFTING WEST LATER TODAY. //DISCUSSION...UPDATED 06Z... ISOLATED MVFR CIGS ARE LARGELY PASSING SOUTH OF A KVYS-KMGC LINE...WITH A VFR DECK SLIDING SE THROUGH THE AREA THIS EVENING. THE VFR DECK WILL CONTINUE MOVING SE AND SHOULD CLEAR THE AREA BY DAYBREAK...WITH ANY ADDITIONAL LAKE INDUCED MVFR TO BE EAST OF KGYY. ONLY CLOUDS LEFT WILL BE PASSING HIGH CLOUDS FROM A LOW IN COLORADO. OTHERWISE...HIGH PRESSURE NOSES SOUTH INTO THE PLAINS TODAY WHICH WILL ALONG NORTH- NORTHWEST WINDS TO TAKE ON A MORE WESTERLY COMPONENT THROUGH THE DAY...LARGELY STAYING FROM 9-12 KT THROUGH THE PERIOD. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH IN WINDS. //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR. STIFF SOUTHWEST WINDS. THURSDAY-FRIDAY...VFR. WEST-SOUTHWEST WINDS. SATURDAY-SUNDAY...CHANCE OF SNOW AND IFR. MTF && .MARINE... 304 PM CST NORTH TO NORTHWEST WINDS PERSIST ACROSS THE LAKE TONIGHT...THEN GRADUALLY BACK SOUTHWEST BY WEDNESDAY AND INCREASE TO GALES BY WEDNESDAY AFTERNOON OR EVENING. IT IS NOT CERTAIN HOW EFFECTIVELY THESE SOMEWHAT MILDER SOUTHWEST WINDS WILL SUPPORT STRONG GALES OVER THE COLD WATER...BUT GALES DO APPEAR LIKELY. UNTIL WINDS TURN AWAY FROM NORTH AND NORTHWEST...CONDITIONS WILL BE FAVORABLE FOR SMALL CRAFT HEADLINES FOR THE FIRST HALF OF THE WEEK...AND ESPECIALLY IN THE INDIANA NEARSHORE WATERS. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL MIDNIGHT WEDNESDAY. GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567- LMZ868...9 AM WEDNESDAY TO 3 AM THURSDAY. GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON WEDNESDAY TO 3 AM THURSDAY. && $$ 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 NATIONAL WEATHER SERVICE LINCOLN IL 1128 PM CST Mon Dec 29 2014 .UPDATE... ISSUED AT 900 PM CST MON DEC 29 2014 The lift being generated in the post frontal airmass has been very weak, based on radar returns and local observations. Have only seen isolated reports of flurries so far. A clearing line just north of the band of clouds/flurries is progressing southward, which would spell an end to the very narrow channel of lift/clouds/flurries. Have updated the sky grids to account for some clearing later tonight at least across the northern counties. Less cloud cover would mean colder lows that we currently have, a bit more toward the colder guidance numbers. Have trimmed a few degrees from lows NW of a line from SPI to BMI. Will keep a mention of flurries in tonight`s forecast following the trek of the band of clouds to the SE. No other significant changes needed this evening. Tomorrow looks like a colder but mostly sunny day. Updated info will be available shortly. && .SHORT TERM...(Tonight) ISSUED AT 315 PM CST MON DEC 29 2014 The 18Z surface analysis indicated the leading edge of the Arctic airmass, ahead of an intense high pressure center in the Canadian Rockies, was sinking just south of I-80. Clouds associated with cold air undercutting were along the I-74 corridor at 20z/2 pm CST. This area of cloudiness, along with low clouds in southern Iowa/northern Missouri will overspread central and eventually southeast Illinois this evening. There should be enough weak forcing for snow flurries, particularly in central Illinois this evening, and the rest of the forecast area late tonight as the short range models point to weak lift just behind the strongest low level cold advection. The HRRR model is trying to produce some measurable snow from Bloomington to near Taylorville between 6 pm and Midnight. At this point, it is the only model, doing this and has most likely latched on to the area of light snow around Pontiac. Will keep an eye on this, but for now will stick to the mention of flurries. The numerical guidance appears to be on the colder side due to less cloud cover and stronger cold advection. Thus, will be going with lows roughly 5 degrees warmer than guidance in central IL and 2-3 degrees warmer in southeast IL due to forecast cloud cover. && .LONG TERM...(Tuesday through Monday) ISSUED AT 315 PM CST MON DEC 29 2014 The narrow band of flurries will continue into Tuesday morning, but should dissipate by afternoon. Behind this area, and strong 1050mb high pressure area will drop into the region. This high will bring dry weather to the area through Thur night, as well as well below normal temps through the period. With the center of the high dropping into the plains Tue night, the coldest temps are expected to be Tue night through Wed. Northwesterly winds Tue night will still be around 10mph, so there could be enough mixing to prevent the bottom from dropping out on the temps. However, single digits are still expected over half of the CWA, and combined with the wind speeds, below zero wind chills are probably Tue night/Wed morning. Beyond this, the high pressure will slide further south into the southern plains by Thursday night. Temps may warm slightly, but only to back around normal. The return of slightly warmer temps and moisture will not occur until the high pressure area move into the southeastern US Thur night and Fri. However, along with this will come the chance of pcpn to the area for the end of the week and the weekend. The questions still remain as to the timing of the pcpn return, how warm it will get, and what p-type will occur. Both the GFS and ECMWF continue to not agree on the overall solution with this system. However, there is some agreement as to how the upper level will evolve into Saturday. The upper level low pressure area will weaken and get lifted out into the flow over the weekend. ECMWF is much quicker with this than the GFS. Models also agree that the pcpn will not really begin until Fri night/Sat morning. However, there still remains a chance of pcpn Friday in the southeast, so will keep chance pops there, though would not be surprised to see this change later. Beyond this, models do not agree with location of pcpn and sfc low pressure area. With the ECMWF being quicker with the upper level system, it keeps the low further south and therefore has very little pcpn in our area...and only in the extreme southeast. The GFS is further north with the low, but has shifted it east since yesterday`s model runs. However, it keeps pcpn over the area through the weekend, just not as much as before; and with the low east, temps may not get as warm, thereby effecting the p-type through the weekend. Will still be keeping the p-type simple and just going with snow, becoming rain or snow, then snow at night and rain and/or snow again during the daytime. The chance of pcpn will continue into Sat night. Sunday and Monday will be dry for now as the system should be well east of the area. Temps in the extended will warm, with the warmest temps being on Saturday and then cooling back off by Monday as another shot of colder air slides into the area. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 1128 PM CST MON DEC 29 2014 The weak cold front has pretty much dissipated this evening, with just a lingering band of clouds and possibly a few flurries drifting southward across the area. In general, a 2-4 hour period of MVFR clouds could occur over the terminal sites the rest of the night. The base cloud layer appears to be very ragged, and periods of MVFR could be broken up by VFR conditions. Have included flurries only at BMI, with dry conditions elsewhere. No impacts are expected from any snowfall overnight. Mid clouds are indicated in the forecast soundings for the day on Tuesday, with gradual lowering of the mid-deck Tuesday evening down to 10K feet. Breaks in the mid-clouds appears likely based on the amount of dry air above and below the cloud layer. Winds will start out NNE, then shift to the N by sunrise and NW Tuesday afternoon. Wind speeds will generally hover btwn 6-9kt at night and 9-12kt during the day. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SHORT TERM...Miller LONG TERM...Auten AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1115 PM CST MON DEC 29 2014 .SHORT TERM... 323 PM CST REMAINDER OF THIS AFTERNOON AND TONIGHT... LAKE EFFECT SNOW HAS LARGELY BEEN A NON-EVENT THIS AFTERNOON... MAINLY DUE TO VERY DRY LOW LEVEL AIR IN PLACE OVER NERN IL/NWRN...WITH DEWPOINTS IN THE UPPER TEENS IN SPITE OF THE NELY FETCH OFF LAKE LAKE MICHIGAN WHERE WATER TEMPERATURES ARE STILL IN THE MIDDLE TO UPPER 30S. THE MAIN IMPACT OF THE LAKE HAS BEEN A BKN-OVC STRATOCU DECK MOVING OFF OF THE LAKE. HOWEVER...THERE HAS BEEN SOME SCT LIGHT SNOW WITH THE COLD FRONT/LEADING EDGE OF THE ARCTIC AIRMASS BUILDING ACROSS THE MISSISSIPPI VALLEY AND INTO THE OHIO VALLEY. WHILE DEEP LAYER MOISTURE HAS BEEN MEAGER...THERE IS JUST ENOUGH FORCING TO SQUEEZE OUT SOME ISOLD AREAS OF LIGHT SNOW...MAINLY OVER PORTIONS OF THE AREA SOUTH OF I-80. FOR THE OVERNIGHT HOURS...AS THE HIGH CONTINUES TO SPREAD SOUTH AND EAST AND THE CENTER OF THE HIGH BUILDS INTO THE NRN PLAINS/NRN ROCKIES...LOW LEVEL FLOW SHOULD GRADUALLY BACK THROUGH NLY TO WNWLY. THE LONGER LAKE FETCH WHEN WINDS BECOME NLY COULD STILL HELP BRING SOME LAKE EFFECT SNOW SHOWERS TO NWRN INDIANA...BUT HAVE BACKED OFF ON QPF/SNOW AMOUNTS...WHILE MAINTAINING THE LIKELY POPS...WITH THE IDEA OF A HIGH POP-LOW QPF SCENARIO. SO...STILL THINK THERE COULD BE SOME ACCUMULATING LAKE EFFECT SNOW OVER PORTIONS OF NWRN INDIANA NEAR THE LAKE...BUT AMOUNTS WILL LIKELY BE LIGHT. AS THE ARCTIC AIRMASS CONTINUES TO SPREAD SOUTH AND EAST...EXPECT LOWS TONIGHT TO DROP TO NEAR 10F OVER THE ROCKFORD AREA...WHILE LOCATIONS EAST OF THE I-55 CORRIDOR SHOULD BE IN THE UPPER TEENS TO LOWER 20S. KREIN && .LONG TERM... 323 PM CST TUESDAY THROUGH MONDAY... WHILE A COOLING TREND INITIATED BEGAN SUNDAY FOLLOWING THE PASSAGE OF A COLD FRONT LATE SATURDAY...THE MORE SIGNIFICANT COOLING TREND IS NOW UNDERWAY AS THE TRUE ARCTIC AIRMASS SPREADS ACROSS THE REGION. AS OF 3PM CST MONDAY AFTERNOON...TEMPERATURES IN THE NORTHERN PLAINS RANGED FROM THE SINGLE DIGITS ABOVE 0F TO THE SINGLE DIGITS BELOW ZERO WITH DEWPOINTS OF -10 TO -15F. THE COLD AIR IS STILL EXPECTED TO SPREAD ACROSS THE LOCAL AREA...BUT THE COLDEST AIR SHOULD REMAIN TO THE WEST...OVER THE PLAINS AS THE CENTER OF THE HIGH DROPS FROM THE NORTHERN ROCKIES TONIGHT TO THE LOWER MISSISSIPPI VALLEY BY THURSDAY MORNING. CONDITIONS ACROSS THE AREA SHOULD GENERALLY BE DRY THROUGH THURSDAY...WITH BELOW NORMAL TEMPERATURES AND AMPLE SUNSHINE AS THE SFC HIGH PRESSURE BUILDS ACROSS THE REGION. STILL ANTICIPATE THAT THE LOWEST TEMPERATURES SHOULD BE TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE SFC RIDGE AXIS BUILDS ACROSS THE AREA. WILL CARRY MIN TEMPS FOR WEDNESDAY MORNING IN THE SINGLE DIGITS FOR THE ENTIRE CWA...RANGING FROM ARND 3F OVER THE ROCKFORD AREA TO 8-9F EAST OF THE I-57 CORRIDOR. THERE IS SOME CONCERN THAT THE TEMP FORECAST MAY BE A BIT TOO LOW...CONSIDERING WINDS SHOULD REMAIN 5-10 MPH OVERNIGHT AND THERE IS NO SNOW COVER. HOWEVER...EVEN THOUGH THE AIRMASS WILL BE VERY DRY AND SKIES SHOULD BE MOSTLY CLEAR...EXPECT THAT THE LOWER TEMPERATURES WILL BE MORE DRIVEN BY ADVECTION OF COLDER AIR FROM THE CENTRAL PLAINS...WITH THE CENTER OF A 1050MB HIGH WILL BE CENTERED ALONG THE KANSAS COLORADO BORDER...WITH A RIDGE AXIS EXTENDING TO THE EAST ACROSS CNTRL ILLINOIS AND INTO THE UPPER OHIO VALLEY. WITH A DIGGING TROUGH DROPPING THROUGH SCNTRL CANADA...A MODEST WLY GRADIENT WILL BE IN PLACE...KEEPING WINDS FROM BECMG CALM. SO...EVEN THOUGH THERE IS NO SNOW COVER OR CALM WINDS TO ALLOW FOR STRONG RADIATIVE COOLING TO CAUSE THE TEMPERATURES TO DROP INTO THE SINGLE DIGITS...FEEL THAT THERE WILL BE ENOUGH ADVECTION OF COLD AIR FROM THE CNTRL PLAINS TO BRING THE LOW TEMPERATURES. THE MAIN IMPACT OF THIS COLD AIR AND RELATIVELY BREEZY CONDITIONS WILL BE FOR WIND CHILL READINGS TO DROP TO -5 TO -13 ACROSS THE CWA...WHICH WOULD THE COLDEST SINCE LATE NOVEMBER. THE OTHER FORECAST CONCERN FOR THE EXTENDED FORECAST PERIOD WILL BE ASSOCIATED WITH A CLOSED LOW EXPECTED TO DROP INTO THE DESERT SOUTHWEST WEDNESDAY AND WEDNESDAY NIGHT AS A STRONG PACIFIC SHORTWAVE DROPS DOWN THE WEST COAST. THE MODELS HAVE BEEN VERY CONSISTENT ON THE DEVELOPMENT OF THIS FEATURE...BUT THERE IS STILL A VARIETY OF SOLUTIONS FROM THE VARIOUS MODELS IN THE TIMING OF EJECTING THE SYSTEM OUT OF THE SRN ROCKIES AND TRACKING ACROSS THE SOUTHERN PLAINS AND THEN LIFTING INTO THE OHIO VALLEY. THE GFS/GEM REMAIN ON THE FASTER END OF THE FORECAST ENVELOPE WHILE THE ECMWF IS THE CONSISTENTLY SLOWER SOLUTION. WHILE THE SLOWER SOLUTION IS STILL FAVORED...CONFIDENCE IS STILL LOW THAT THE EVENTUAL PROGRESSION OF THE SYSTEM COULD STILL BE SLOWER THAN WHAT THE ECMWF CONTINUES TO INDICATE. SO...WILL MAINTAIN THE IDEA OF A SLOWER SOLUTION. THE MAIN TREND FOR THE SENSIBLE WEATHER FEATURES SHOULD BE A WARMING TREND WITH MAX TEMPS REBOUNDING INTO THE 30S FOR FRIDAY AND SATURDAY AS UPPER HEIGHTS RISE IN ADVANCE OF THE UPPER LOW EJECTING OUT OF THE DESERT SOUTHWEST. THERE IS DECENT CONFIDENCE IN THIS GENERAL TREND. THERE IS ALSO DECENT CONFIDENCE IN THE IDEA OF INCREASING POPS INTO THE WEEKEND...WHICH IS SLOW THAN PREVIOUSLY FORECAST AND IN LINE WITH A SLOWER PROGRESSION OF THE SYSTEM. HOWEVER THERE IS RELATIVELY LOW CONFIDENCE IN TIMING AND AMOUNT OF PCPN AS THERE IS STILL THE CHANCE FOR SOME PHASING OF THE SRN STREAM SYSTEM WITH NRN STREAM SHORT WAVE ENERGY DROPPING OUT OF THE NRN PLAINS AND ACROSS THE GREAT LAKES. SO...WILL LIMIT POPS TO CHANCE LEVELS FOR NOW WITH THE TREND TO DELAY THE ONSET OF ANY PCPN INTO LATER IN THE FORECAST PERIOD. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * NORTH-NORTHWEST WINDS 10 KT OR HIGHER GRADUALLY SHIFTING WEST LATER TODAY. //DISCUSSION...UPDATED 06Z... ISOLATED MVFR CIGS ARE LARGELY PASSING SOUTH OF A KVYS-KMGC LINE...WITH A VFR DECK SLIDING SE THROUGH THE AREA THIS EVENING. THE VFR DECK WILL CONTINUE MOVING SE AND SHOULD CLEAR THE AREA BY DAYBREAK...WITH ANY ADDITIONAL LAKE INDUCED MVFR TO BE EAST OF KGYY. ONLY CLOUDS LEFT WILL BE PASSING HIGH CLOUDS FROM A LOW IN COLORADO. OTHERWISE...HIGH PRESSURE NOSES SOUTH INTO THE PLAINS TODAY WHICH WILL ALONG NORTH- NORTHWEST WINDS TO TAKE ON A MORE WESTERLY COMPONENT THROUGH THE DAY...LARGELY STAYING FROM 9-12 KT THROUGH THE PERIOD. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH IN WINDS. //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR. STIFF SOUTHWEST WINDS. THURSDAY-FRIDAY...VFR. WEST-SOUTHWEST WINDS. SATURDAY-SUNDAY...CHANCE OF SNOW AND IFR. MTF && .MARINE... 304 PM CST NORTH TO NORTHWEST WINDS PERSIST ACROSS THE LAKE TONIGHT...THEN GRADUALLY BACK SOUTHWEST BY WEDNESDAY AND INCREASE TO GALES BY WEDNESDAY AFTERNOON OR EVENING. IT IS NOT CERTAIN HOW EFFECTIVELY THESE SOMEWHAT MILDER SOUTHWEST WINDS WILL SUPPORT STRONG GALES OVER THE COLD WATER...BUT GALES DO APPEAR LIKELY. UNTIL WINDS TURN AWAY FROM NORTH AND NORTHWEST...CONDITIONS WILL BE FAVORABLE FOR SMALL CRAFT HEADLINES FOR THE FIRST HALF OF THE WEEK...AND ESPECIALLY IN THE INDIANA NEARSHORE WATERS. LENNING && .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 NATIONAL WEATHER SERVICE LINCOLN IL 909 PM CST Mon Dec 29 2014 .UPDATE... ISSUED AT 900 PM CST MON DEC 29 2014 The lift being generated in the post frontal airmass has been very weak, based on radar returns and local observations. Have only seen isolated reports of flurries so far. A clearing line just north of the band of clouds/flurries is progressing southward, which would spell an end to the very narrow channel of lift/clouds/flurries. Have updated the sky grids to account for some clearing later tonight at least across the northern counties. Less cloud cover would mean colder lows that we currently have, a bit more toward the colder guidance numbers. Have trimmed a few degrees from lows NW of a line from SPI to BMI. Will keep a mention of flurries in tonight`s forecast following the trek of the band of clouds to the SE. No other significant changes needed this evening. Tomorrow looks like a colder but mostly sunny day. Updated info will be available shortly. && .SHORT TERM...(Tonight) ISSUED AT 315 PM CST MON DEC 29 2014 The 18Z surface analysis indicated the leading edge of the Arctic airmass, ahead of an intense high pressure center in the Canadian Rockies, was sinking just south of I-80. Clouds associated with cold air undercutting were along the I-74 corridor at 20z/2 pm CST. This area of cloudiness, along with low clouds in southern Iowa/northern Missouri will overspread central and eventually southeast Illinois this evening. There should be enough weak forcing for snow flurries, particularly in central Illinois this evening, and the rest of the forecast area late tonight as the short range models point to weak lift just behind the strongest low level cold advection. The HRRR model is trying to produce some measurable snow from Bloomington to near Taylorville between 6 pm and Midnight. At this point, it is the only model, doing this and has most likely latched on to the area of light snow around Pontiac. Will keep an eye on this, but for now will stick to the mention of flurries. The numerical guidance appears to be on the colder side due to less cloud cover and stronger cold advection. Thus, will be going with lows roughly 5 degrees warmer than guidance in central IL and 2-3 degrees warmer in southeast IL due to forecast cloud cover. && .LONG TERM...(Tuesday through Monday) ISSUED AT 315 PM CST MON DEC 29 2014 The narrow band of flurries will continue into Tuesday morning, but should dissipate by afternoon. Behind this area, and strong 1050mb high pressure area will drop into the region. This high will bring dry weather to the area through Thur night, as well as well below normal temps through the period. With the center of the high dropping into the plains Tue night, the coldest temps are expected to be Tue night through Wed. Northwesterly winds Tue night will still be around 10mph, so there could be enough mixing to prevent the bottom from dropping out on the temps. However, single digits are still expected over half of the CWA, and combined with the wind speeds, below zero wind chills are probably Tue night/Wed morning. Beyond this, the high pressure will slide further south into the southern plains by Thursday night. Temps may warm slightly, but only to back around normal. The return of slightly warmer temps and moisture will not occur until the high pressure area move into the southeastern US Thur night and Fri. However, along with this will come the chance of pcpn to the area for the end of the week and the weekend. The questions still remain as to the timing of the pcpn return, how warm it will get, and what p-type will occur. Both the GFS and ECMWF continue to not agree on the overall solution with this system. However, there is some agreement as to how the upper level will evolve into Saturday. The upper level low pressure area will weaken and get lifted out into the flow over the weekend. ECMWF is much quicker with this than the GFS. Models also agree that the pcpn will not really begin until Fri night/Sat morning. However, there still remains a chance of pcpn Friday in the southeast, so will keep chance pops there, though would not be surprised to see this change later. Beyond this, models do not agree with location of pcpn and sfc low pressure area. With the ECMWF being quicker with the upper level system, it keeps the low further south and therefore has very little pcpn in our area...and only in the extreme southeast. The GFS is further north with the low, but has shifted it east since yesterday`s model runs. However, it keeps pcpn over the area through the weekend, just not as much as before; and with the low east, temps may not get as warm, thereby effecting the p-type through the weekend. Will still be keeping the p-type simple and just going with snow, becoming rain or snow, then snow at night and rain and/or snow again during the daytime. The chance of pcpn will continue into Sat night. Sunday and Monday will be dry for now as the system should be well east of the area. Temps in the extended will warm, with the warmest temps being on Saturday and then cooling back off by Monday as another shot of colder air slides into the area. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 543 PM CST MON DEC 29 2014 The arctic front will continue to slide south and east tonight, as it dissipates. Flurries will be the primary precipitation, and will develop behind the front in the region of lift. The RAP and HRRR are both indicating the area of light snow that lowered visibility to 3 miles will drift south through Bloomington and eventually just east of Lincoln toward Taylorville. It is projected to weaken as it shifts south, but Bloomington may see visibility drop to MVFR levels in light snow for a couple of hours. The prevailing cloud cover will lower to MVFR at all TAF sites this evening as the arctic front progresses southeast. The flurries should dissipate late tonight and MVFR clouds will break up starting around 16z at PIA and eventually clearing at DEC around 20z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SHORT TERM...Miller LONG TERM...Auten AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS WICHITA KS
310 AM CST TUE DEC 30 2014 .SYNOPSIS... ISSUED AT 308 AM CST TUE DEC 30 2014 LARGE POSITIVE TILTED UPPER TROUGH EXTENDS FROM THE NORTHERN PLAINS INTO NORTHERN CA WITH THE MAIN VORT LOBE OVER THE WESTERN PORTION OF THIS TROUGH. AT THE SURFACE...ARCTIC AIR IS SPILLING SOUTH ACROSS THE PLAINS WITH NEGATIVE TEMP VALUES NOW ENCOMPASSING THE NORTHERN HALF OF NEBRASKA. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 308 AM CST TUE DEC 30 2014 LIGHT SNOW HAS BEEN PERSISTENT OVERNIGHT FOR AREAS ALONG AND WEST OF I-135 AND AM EXPECTING THIS TO CONTINUE THROUGH AT LEAST THE MORNING HOURS AND POSSIBLY INTO THE AFTERNOON. FEEL CONFIDENT IN THIS AS ISENTROPIC LIFT IN THE 280-285K LAYER REMAINS PRETTY MUCH UNCHANGED FROM WHAT IS OCCURRING NOW. EVEN THOUGH MOST SITES WILL NOT TIP OFF A 0.01 OF PRECIP...WILL RUN WITH HIGH POP WORDING AS WHAT IS OCCURRING IS MORE THAN JUST FLURRIES WITH SOME VISIBILITIES AT OR LESS THAN 3SM. WILL KEEP WITH CURRENT HEADLINE MAINLY DUE TO COMING CLOSE TO WIND CHILL CRITERIA. THE FRIGID AIRMASS WILL REMAIN IN PLACE TONIGHT THROUGH WED WITH TEMPS AROUND 20 DEGREES BELOW NORMAL. WOULD NOT BE SHOCKED IF WE GET SOME FLURRIES TO LINGER TONIGHT OVER THE SOUTHWEST PORTION OF THE FORECAST AREA AS THE LIFT IS SLOW TO MOVE OUT. THE MAIN VORT LOBE OUT WEST IS EXPECTED TO CUT OFF AND TRACK ACROSS THE DESERT SOUTHWEST BY THU AND WILL BECOME THE FOCUS FOR THE EXTENDED PERIODS. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 308 AM CST TUE DEC 30 2014 THROUGH 00Z SAT BOTH THE ECMWF AND GFS REMAIN FAIRLY SIMILAR IN TRACKING THE CLOSED LOW OVER EASTERN NM. HOWEVER...THESE MODELS AGAIN START TO DEVIATE FOR THE FRI NIGHT THROUGH SAT TIME FRAME. THE GFS IS CONTINUING THE TREND OF LIFTING THE IMPULSE FURTHER NORTH COMPARED TO THE ECMWF. THE GFS SOLUTION WOULD RESULT IN WIDESPREAD WINTRY PRECIP FOR MOST OF THE FORECAST AREA FRI NIGHT INTO SAT MORNING WITH THE ECMWF KEEPING MOST OF THE PRECIP SOUTH OF THE KS/OK BORDER. HAVE A SLIGHT LEAN TO THE GFS SINCE IT HAS BEEN A BIT MORE CONSISTENT AND FEEL THAT AT LEAST A PORTION OF OUR FORECAST AREA WILL BE IMPACTED BY WINTRY PRECIP OVER THE WEEKEND. LAWSON && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1135 PM CST MON DEC 29 2014 LIGHT SNOW IS MOVING ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA IMPACTING KRSL/KHUT/KICT AND WILL SOON IMPACT KSLN. MVFR TO IFR CEILINGS AND VISIBILITIES ARE ALSO IMPACTING THE TERMINALS. EXPECT THIS TO PERSIST THROUGH THE OVERNIGHT HOURS. THE SHORT- TERM HIGHER RES RUC GUIDANCE SHOWS THE SNOW DIMINISHING AROUND SUNRISE...WHILE THE NAM KEEPS PRECIP AROUND LONGER. HAVE TRENDED TOWARD THE RUC AT THIS TIME IN THE TAFS ENDING THE SNOW AROUND SUNRISE AND EVENTUALLY LIFTING THE CEILINGS TO HIGH END MVFR AND IN SOME CASES VFR BY THE END OF THE PERIOD. NORTH TO NORTHEASTERLY WINDS WILL PERSIST THROUGH THE FORECAST. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 18 4 22 14 / 30 10 0 0 HUTCHINSON 13 2 21 13 / 40 10 0 0 NEWTON 15 2 21 13 / 20 10 0 0 ELDORADO 18 4 22 14 / 20 10 0 0 WINFIELD-KWLD 21 6 24 16 / 20 10 0 0 RUSSELL 7 -3 15 8 / 30 10 0 0 GREAT BEND 8 -2 17 10 / 30 10 0 0 SALINA 12 -1 18 12 / 30 10 0 0 MCPHERSON 12 1 20 12 / 30 10 0 0 COFFEYVILLE 30 9 27 16 / 10 10 0 0 CHANUTE 25 5 24 15 / 10 10 0 0 IOLA 23 4 24 15 / 10 10 0 0 PARSONS-KPPF 27 7 25 16 / 10 10 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR KSZ032-033-047- 048. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1135 PM CST MON DEC 29 2014 ...UPDATED FOR 06Z AVIATION DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 234 PM CST MON DEC 29 2014 ARCTIC AIR OVER THE DAKOTAS/NEBRASKA WAS CONTINUING TO SURGE SOUTH AND WILL SPREAD ACROSS KANSAS FOR TONIGHT AND REMAIN OVER THE AREA FOR THE NEXT COUPLE OF DAYS. MEANWHILE SNOW CURRENTLY OVER NORTHWEST KANSAS WILL EXPAND EASTWARD INTO CENTRAL KANSAS FOR TONIGHT WITH SOME LIGHT ACCUMULATIONS POSSIBLE...WITH A TRACE TO 2 INCHES POSSIBLE. THE SNOW SHOULD BEGIN TO TAPER OFF QUICKLY FOR TUESDAY MORNING...AS THE VERTICAL MOTION FROM UPPER LEVEL WAVE DIMINISHES. WIND CHILLS WILL DROP TO DANGEROUS LEVELS FOR TUESDAY MORNING AND COULD AGAIN FOR WEDNESDAY MORNING ACROSS CENTRAL KANSAS. A WIND CHILL ADVISORY COULD BE HOISTED BY LATER SHIFTS FOR WEDNESDAY MORNING IF TRENDS MAINTAIN. TEMPERATURES SHOULD MODIFY AND WARM A BIT COME THURSDAY AS DOWNSLOPE FLOW HELPS BOOSTS DAYTIME HIGHS. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 234 PM CST MON DEC 29 2014 SOME UNCERTAINTY REMAINS BETWEEN THE GFS/ECMWF MODEL AS EXPECTED THIS FAR OUT IN TIME WITH POSITIONING OF THE FRI/SAT SYSTEM...BUT NONE THE LESS WINTER PRECIPITATION STILL SEEMS REASONABLE FOR MAINLY SOUTH CENTRAL/SOUTHEAST KANSAS. BELOW NORMAL TEMPERATURES WILL CONTINUE FOR SUNDAY AND MONDAY AS SURFACE HIGH PRESSURE BUILDS OVER KANSAS...AND TEMPERATURES COULD BE EVEN COLDER IF FRESH SNOW FALLS ACROSS THE REGION. JAKUB && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1135 PM CST MON DEC 29 2014 LIGHT SNOW IS MOVING ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA IMPACTING KRSL/KHUT/KICT AND WILL SOON IMPACT KSLN. MVFR TO IFR CEILINGS AND VISIBILITIES ARE ALSO IMPACTING THE TERMINALS. EXPECT THIS TO PERSIST THROUGH THE OVERNIGHT HOURS. THE SHORT- TERM HIGHER RES RUC GUIDANCE SHOWS THE SNOW DIMINISHING AROUND SUNRISE...WHILE THE NAM KEEPS PRECIP AROUND LONGER. HAVE TRENDED TOWARD THE RUC AT THIS TIME IN THE TAFS ENDING THE SNOW AROUND SUNRISE AND EVENTUALLY LIFTING THE CEILINGS TO HIGH END MVFR AND IN SOME CASES VFR BY THE END OF THE PERIOD. NORTH TO NORTHEASTERLY WINDS WILL PERSIST THROUGH THE FORECAST. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 15 19 4 21 / 60 10 10 0 HUTCHINSON 10 15 2 20 / 100 20 10 0 NEWTON 11 17 2 20 / 50 10 10 0 ELDORADO 14 20 4 22 / 30 10 10 0 WINFIELD-KWLD 18 22 6 23 / 30 10 10 0 RUSSELL 4 9 -3 18 / 100 30 10 0 GREAT BEND 6 10 -2 18 / 100 30 10 0 SALINA 8 12 -1 19 / 90 10 10 0 MCPHERSON 9 14 1 20 / 100 10 10 0 COFFEYVILLE 23 28 9 25 / 30 10 10 0 CHANUTE 19 24 5 23 / 10 10 10 0 IOLA 18 23 4 22 / 10 10 10 0 PARSONS-KPPF 21 26 7 24 / 20 10 10 0 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR KSZ032-033- 047-048. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1133 PM EST MON DEC 29 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 403 PM EST MON DEC 29 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH EXTENDING FROM NRN QUEBEC THROUGH THE NRN PLAINS INTO THE ROCKIES. THE NEXT SIGNIFICANT UPSTREAM SHORTWAVE TROUGH WAS DROPPING SOUTH THROUGH NRN SASK/MANITOBA. AT THE SFC...1054 MB ARCTIC HIGH PRES OVER ALBERTA EXTENDED INTO THE NRN PLAINS AND UPPER MS VALLEY AND NRN LAKES RESULTING IN A FLOW OF VERY COLD AIR ACROSS LAKE SUPERIOR ON NW WINDS. DESPITE 850 MB TEMPS NEAR -21C...LES HAS BEEN LIMITED BY THE VERY DRY UPSTREAM CONDITIONS AS THE BACK EDGE OF THE CLOUDS WAS CLOSER TO THE MI SHORE IN THE WEST AND NEAR THE CENTER OF THE NRN LAKE. RADAR SHOWED MAINLY WEAK WIND PARALLEL BANDS INTO THE ERN CWA. TONIGHT...WITH THE LOSS OF DAYTIME MIXING AND ONSET OF LAND BREEZES THE LES MAY BECOME BETTER ORGANIZED. THE PERSISTENT 290-300 FLOW LES IS EXPECTED TO CONTINUE BUT WILL BE LIMITED BY 4K FT INVERSION HEIGHTS AND A LACK OF ANY SUSTAINED AREAS OF LOW LEVEL CONV. THE LONGER FETCH INTO THE EAST WILL SUPPORT SNOWFALL AMOUNTS IN THE 2 TO 4 INCH RANGE WITH SLR VALUES NEAR 25/1...E OF MUNISING WHILE OVER THE WEST ONLY 1 TO 3 INCH AMOUNTS ARE EXPECTED. WIND CHILL VALUES OVER THE INTERIOR WEST COULD FALL INTO THE -20 TO -25 RANGE AS SFC TEMPS DROP TO AROUND -8F. HOWEVER...WINDS SHOULD REMAIN LESS THAN 10 MPH. TUESDAY...EXPECT THE WINDS TO BACK MORE WRLY AHEAD OF THE SASK/MANITOBA SHORTWAVE TROUGH...ESPECIALLY IN THE AFTERNOON. OTHERWISE...LIGHT TO MODERATE WNW FLOW LES WILL CONTINUE WITH 850 MB TEMPS REMAINING NEAR -22C AND INVERSION HEIGHTS AROUND 4K FT. THE STRONGEST LOW LEVEL CONV...INFLUENCED BY LAKE-INDUCED TROUGHING IS EXPECTED OVER THE ERN LAKE WITH SOME STRONGER BANDS POSSIBLE CLIPPING THE NE PORTION OF LUCE COUNTY. FOR NOW...EXPECT ADDITIONAL ACCUMULATIONS IN THE 2 TO 4 INCH RANGE E OF P53 AND 1 TO 3 INCHES INTO THE WEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 426 PM EST MON DEC 29 2014 A BROAD UPPER TROUGH OVER CANADA AND THE GREAT LAKES REGION WILL LEAD TO BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW THROUGH THE FIRST WEEK OF 2015. AT THE START OF THE PERIOD...THE AREA WILL STILL BE BETWEEN A STRONG HIGH OVER WESTERN NEBRASKA AND A LOW JUST TO THE NORTH OF HUDSON BAY. ALOFT...A SHORTWAVE WILL JUST BE DEPARTING THE AREA AND BRINGING ONE LAST SURGE OF -21C 850MB TEMPS TO THE AREA. THUS...EXPECT NORTHWEST FLOW LAKE EFFECT TO STILL BE ONGOING TUESDAY EVENING. A SURFACE TROUGH DIVING SOUTHEAST FROM THE HUDSON BAY LOW WILL LEAD TO BACKING FLOW ON TUESDAY NIGHT INTO WEDNESDAY MORNING...SHIFTING THE LAKE EFFECT TO THE WESTERLY FLOW AREAS (THE KEWEEANW AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE EAST OF MUNISING). SNOWFALL AMOUNTS TUESDAY NIGHT CONTINUE TO LOOK LIGHT AND FLUFFY AS INVERSION HEIGHTS ARE STILL IN THE 4-5KFT RANGE WITH MUCH OF THE CLOUD LAYER IN THE DGZ. WILL FOLLOW THE SNOWFALL AMOUNTS SEEN OVER THE LAST 12/24HRS AND HAVE THEM BE IN THE 1-4IN/12HRS RANGE. TUESDAY NIGHT WILL BE ANOTHER COLD NIGHT AWAY FROM THE LAKE EFFECT CLOUDS...WITH LOWS FALLING INTO THE SINGLE DIGITS AND LOWER TEENS BELOW ZERO. WIND CHILLS WILL BECOME A CONCERN LATE IN THE NIGHT INTO WEDNESDAY MORNING...AS THE WEST TO SOUTHWEST WINDS BEGIN TO INCREASE WITH THE TIGHTENING PRESSURE GRADIENT. WHILE THIS WILL LIKELY INCREASE MIXING AND IN TURN WARM TEMPS SLIGHTLY (HELPED BY SOME MID CLOUDS MOVING IN)...THERE WILL STILL BE A PERIOD LATE TUESDAY NIGHT INTO WEDNESDAY MORNING WHERE WIND CHILL VALUES WILL BE IN THE -20 TO -30 DEGREE RANGE OVER THE INTERIOR LOCATIONS. WILL CONTINUE TO MENTION THIS IN THE HWO AND AN ADVISORY MAY BEEN NEEDED TOMORROW. WITH THE LOW LEVEL WINDS TRYING TO BACK TOWARDS THE SOUTHWEST DURING THE DAY WEDNESDAY...DID TRY TO SHOW BETTER TIMING ON THE LAKE EFFECT SNOW. EXPECT IT TO TRY TO SHIFT OVER THE FAR NORTHERN PART OF THE KEWEENAW BY MID DAY AND WELL OFFSHORE OVER THE EAST. WINDS WILL BECOME QUITE GUSTY DURING THIS PERIOD...WITH MUCH OF UPPER MICHIGAN EXPERIENCING GUSTS IN THE 25 TO 35MPH RANGE. BUT OVER THE KEWEENAW PENINSULA AND CLOSER TO THE TIGHTER PRESSURE GRADIENT...WOULD EXPECT GUSTS TO AT LEAST 40 MPH AND AT TIMES 45-50MPH. THESE WINDS COMBINED WITH THE FLUFFY LAKE EFFECT SEEN OVER THE LAST COUPLE OF DAYS WILL LIKELY LEAD TO SIGNIFICANT BLOWING SNOW DEVELOPING THROUGH THE DAY WEDNESDAY. THEN...AS STRONG SHORTWAVE DIVES SOUTHEAST ACROSS THE UPPER GREAT LAKES REGION DURING THE AFTERNOON AND THE SURFACE TROUGH DURING THE EARLY EVENING...EXPECT WINDS TO SHIFT BACK TO THE WEST AND REFOCUS THE LAKE EFFECT IN THE WESTERLY WIND AREAS. THINK THERE COULD BE A PERIOD OF MODERATE SNOW AS THE WINDS TURN TO THE WEST...DUE TO INVERSION HEIGHTS RISING TO 7KFT AND MUCH OF THE CLOUD STILL IN THE DGZ. THERE ARE A COUPLE DOWNSIDES TO HIGHER SNOWFALL AMOUNTS (TIED TO THE STRONG WINDS)...BUT THERE WILL STILL BE VERY POOR CONDITIONS OVER THE KEWEENAW. FIRST...THE HIGH WINDS WILL LIMIT THE RESIDENCE TIME OVER THE WESTERN LAKE AS THEY SHIFT TO THE WEST. SECOND...THE STRONG WINDS WILL BREAK UP THE DENDRITES FROM THE FAVORABLE CLOUD LAYER AND LEAD TO SMALLER/FRACTURED FLAKES. WHILE THIS WILL LIMIT SNOWFALL AMOUNTS...IT WILL BE MORE EFFECTIVE AT REDUCING VISIBILITIES AND WHEN COMBINED WITH THE BLOWING SNOW...WOULD EXPECT VISIBILITIES BELOW 1/4 MILE AT TIMES LATE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. WILL CONTINUE TO MENTION THESE POOR CONDITIONS FOR THE KEWEENAW IN THE HWO. EXPECT NORTHWEST FLOW LAKE EFFECT TO REESTABLISH ON THURSDAY FOR AREAS DOWNSTREAM FROM LAKE SUPERIOR. ELSEWHERE IN THE U.P...MODELS DIFFER IN THEIR SOLUTIONS ON POTENTIAL SHORTWAVES ZIPPING EAST-SOUTHEAST ACROSS THE AREA. AT TIMES...MODELS HAVE SHOWN LIGHT SNOW ASSOCIATED WITH THESE QUICK WAVES THURSDAY AND AGAIN FRIDAY. BOTH STRENGTH AND LOCATIONS HAS NOT BEEN CONSISTENT IN THE MODELS OVER THE LAST 24 HOURS...SO WILL FOCUS LARGELY ON LAKE EFFECT TURNING TO THE WESTERLY WIND LOCATIONS AND SHOW SLIGHT CHANCES ELSEWHERE. THE UNCERTAINTY CONTINUES INTO THE WEEKEND...AS MODELS DIFFER ON HOW THE CLOSED UPPER LOW THAT DEVELOPS OVER THE SOUTHWEST CONUS TUESDAY INTERACTS WITH THE NORTHERN STREAM JET AS IT SHIFTS EAST ACROSS THE SOUTHERN CONUS. THE 12Z GFS/GEM SOLUTIONS MERGE THE UPPER LOW WITH A MORE AMPLIFIED NORTHERN STREAM TROUGH AND THEN LIFT IT AND A DEVELOPING SURFACE LOW NORTHEAST THROUGH THE LOWER GREAT LAKES SATURDAY NIGHT. MEANWHILE...THE 12Z ECMWF AND ITS ENSEMBLE MEMBERS SHOW A MUCH FLATTER NORTHERN STREAM TROUGH AND DON/T MERGE THE WAVES UNTIL THE EAST COAST ON SUNDAY. THAT WOULD LEAD TO MORE OF A NORTHERLY FLOW LAKE EFFECT FOR THE AREA. THIS WILL DEFINITELY BE SOMETHING TO WATCH OVER THE COMING DAYS. EVEN IF THERE ISN/T A LOW MOVING THROUGH THE LOWER GREAT LAKES...TEMPERATURES WILL BE COLD ENOUGH FOR LAKE EFFECT SNOW AND WILL CONTINUE TO SHOW THE POTENTIAL IN THE GRIDS FOR AREAS NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1133 PM EST MON DEC 29 2014 EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH BETTER CONDITIONS AT SAW. THERE COULD BE TEMPORARY IFR CONDITIONS FOR VISIBILITY IN THE HEAVIER SNOW SHOWERS ESPECIALLY AT CMX. LIKE LAST NIGHT...THERE WILL BE TEMPORARY MVFR CIGS AT SAW OVERNIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 403 PM EST MON DEC 29 2014 EXPECT HEAVY FREEZING SPRAY BY TUESDAY AFTERNOON AND GALES FROM LATE TUESDAY NIGHT THROUGH THURSDAY MORNING. A RIDGE ACROSS THE UPPER GREAT LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS WILL BE AS A HUDSON BAY LOW DRAGS A TROUGH ACROSS LAKE SUPERIOR. THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-45KTS ARE STILL ANTICIPATED /ALONG WITH HEAVY FREEZING SPRAY TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE TRACKS ACROSS THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO 1 PM EST /NOON CST/ THURSDAY FOR LSZ240>243-248>251-263- 265>267. GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ244- 245-264>267. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-241>243-263. HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THURSDAY FOR LSZ244- 245-264. HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246-247. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
341 AM CST TUE DEC 30 2014 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DONT FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASASUREABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1127 PM CST MON DEC 29 2014 NARROW BAND OF MAINLY SCT/BKN MID LEVEL CLOUDS ASSOCIATED WITH A WEAK BOUNDARY WILL AFFECT THE NORTH HALF OF THE FA THROUGH 12Z. AFTER THAT NOT SURE HOW MUCH CLOUD COVER WILL BE LEFT AS MODELS GENERALLY WASH OUT BOUNDARY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016- 024-026>030-038-039-049-052>054. MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017- 022>024-027>032-040. && $$ SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS TULSA OK
1126 PM CST MON DEC 29 2014 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. VFR CIGS ALL SITES WITH LAYERED CLOUDS THROUGHOUT THE PERIOD. CIGS BECOMING MVFR NERN OK SITES FOLLOWING COLD FRONTAL SURGE LATER TONIGHT. CIGS PROBABLY HANG AROUND ON TUESDAY LONGER THAN INDICATED IN MODEL FIELDS. NORTHEASTERLY WIND WILL BACK TO THE NORTH NORTHEAST AND INCREASE WITH FRONTAL PASSAGE. && .PREV DISCUSSION... /ISSUED 904 PM CST MON DEC 29 2014/ ..UPDATE... DISCUSSION... RADAR ECHOES ARE LEAVING THE FORECAST AREA...SO WILL DROP MENTION OF FLURRIES FOR THE REMAINDER OF THE OVERNIGHT PERIOD. 00Z NAM...01Z HRRR AND 02Z RAP ALL APPEAR DRY FOR THE REST OF THE NIGHT. LFM IS MISSING...ALONG WITH BAROTROPIC AND SHIP PAPA DATA. ..HAVING A RIP VAN WINKLE MOMENT... WILL UPDATE TO TAKE OUT FLURRIES AND SPRINKLES. APPEARS THE COLD SURGE IS STILL IN KANSAS...FROM JUST SOUTH OF MKC TO NORTH OF ICT TO NEAR AMA...BASED MAINLY ON LOCATION OF STRONGEST WINDS AND GUSTINESS. PROGRESS HAS BEEN SLOW...BUT ON TARGET FOR TUESDAY MORNING. NO CHANGE TO MINIMUM TEMPS. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...02 AVIATION...69
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
333 AM EST TUE DEC 30 2014 .SYNOPSIS... A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA WITH A STRONG RIDGE OVER THE PACIFIC NORTHWEST AND A TROUGH OVER THE NORTHEAST WILL PRODUCE TWO COLD SURGES. THE FIRST SHOULD PRODUCE COLD WEATHER TROUGH NEW YEARS. A SOUTHERN STREAM STORM COULD BRING A WINTRY MIX AND/OR RAIN TO THE REGION OVER THE WEEKEND AHEAD OF THE FORECAST SECOND SURGE OF COLD CONTINENTAL AIR. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SATELLITE IMAGERY CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT...HOWEVER LATESET RADAR IMAGERSY SHOWS BAND OF FLURRIES/LIGHT SNOW SHOWERS MOVING SE ACROSS PARTS OF THE CENTRAL MTNS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES AND PERHAPS SNOW IN NORTHERN AND SOME CENTRAL AREAS. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/GARTNER NEAR TERM...GRUMM/GARTNER SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
217 AM EST TUE DEC 30 2014 .SYNOPSIS... A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA WITH A STRONG RIDGE OVER THE PACIFIC NORTHWEST AND A TROUGH OVER THE NORTHEAST WILL PRODUCE TWO COLD SURGES. THE FIRST SHOULD PRODUCE COLD WEATHER TROUGH NEW YEARS. A SOUTHERN STREAM STORM COULD BRING A WINTRY MIX AND/OR RAIN TO THE REGION OVER THE WEEKEND AHEAD OF THE FORECAST SECOND SURGE OF COLD CONTINENTAL AIR. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SATELLITE IMAGERY CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SUGGESTS OUR FORECASTS IN SOUTH/CENTRAL ARE TOO CLOUDY. HRRR ALSO SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT IN NORTHWEST. THE WEAK NORTHWEST FLOW OUT OF THE HIGH CENTERED OVER THE TN VALLEY DOES NOT CAUSE THE MODEL TO GENERATE ANY LAKE ENHANCED SNOWS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES AND PERHAPS SNOW IN NORTHERN AND SOME CENTRAL AREAS. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/GARTNER NEAR TERM...GRUMM/GARTNER SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
109 AM EST TUE DEC 30 2014 .SYNOPSIS... A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA WITH A STRONG RIDGE OVER THE PACIFIC NORTHWEST AND A TROUGH OVER THE NORTHEAST WILL PRODUCE TWO COLD SURGES. THE FIRST SHOULD PRODUCE COLD WEATHER TROUGH NEW YEARS. A SOUTHERN STREAM STORM COULD BRING A WINTRY MIX AND/OR RAIN TO THE REGION OVER THE WEEKEND AHEAD OF THE FORECAST SECOND SURGE OF COLD CONTINENTAL AIR. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SATELLITE IMAGERY CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SUGGESTS OUR FORECASTS IN SOUTH/CENTRAL ARE TOO CLOUDY. HRRR ALSO SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT IN NORTHWEST. THE WEAK NORTHWEST FLOW OUT OF THE HIGH CENTERED OVER THE TN VALLEY DOES NOT CAUSE THE MODEL TO GENERATE ANY LAKE ENHANCED SNOWS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES AND PERHAPS SNOW IN NORTHERN AND SOME CENTRAL AREAS. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/GARTNER NEAR TERM...GRUMM/GARTNER SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/GARTNER
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1152 PM EST MON DEC 29 2014 .SYNOPSIS... COLD SURFACE HIGH PRESSURE WILL CONTINUE TO WEDGE DOWN FROM THE NORTH ALONG THE APPALACHIANS TONIGHT WHILE A WEAK UPPER LEVEL DISTURBANCE IS EXPECTED TO PASS FROM WEST TO EAST ACROSS THE AREA TONIGHT THROUGH EARLY TUESDAY. VERY LIGHT PRECIPITATION ASSOCIATED WITH THIS FEATURE IS EXPECTED TO CHANGE OVER TO SNOW ACROSS THE NORTHERN PORTION OF THE REGION...WITH ACCUMULATIONS OF AN INCH OR LESS...MAINLY ALONG AND NORTH OF U.S. 460. DRY BUT CONTINUED COLD HIGH PRESSURE WILL BEGIN TO PUSH IN FROM THE WEST LATER TUESDAY AND LAST UNTIL LATE IN THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... AS OF 635 PM EST MONDAY... MADE A FEW MINOR ADJUSTMENTS TO EXISTING SET OF GRIDS TO BUMP UP PROBABILITY OF PRECIPITATION TO ACCOUNT FOR WIDESPREAD RAIN AND DRIZZLE NOW FALLING ACROSS MUCH OF THE NEW RIVER VALLEY NORTH TOWARD THE ALLEGHANY HIGHLANDS. DESPITE AREAL EXTENT OF PRECIPITATION...AMOUNTS CONTINUE TO BE LIGHT...GENERALLY ONLY AROUND 0.01 INCH/PER HOUR. LATEST UPPER-AIR SOUNDING...RELEASED ABOUT 30 MINUTES AGO...SHOWS LOWEST 3K FEET AGL STILL ABOVE FREEZING AND NEARLY SATURATED...SO IT WILL TAKE MUCH OF THE EVENING...PERHAPS INTO THE EARLY MORNING HOURS...TO DRIVE SNOW LEVELS DOWN FROM HIGHEST RIDGES TO MOUNTAIN VALLEY AREAS...CONSISTENT WITH PREVIOUS FORECAST THINKING. THEREFORE...SNOWFALL TOTALS STILL NOT EXPECTED TO BECOME PROBLEMATIC AS THE NIGHT PROGRESSES...ESPECIALLY CONSIDERING CURRENT WARM GROUND CONDITIONS AND VERY LIGHT FALL RATES. ALSO MADE A FEW TWEAKS TO HOURLY TEMPS/DEW POINT GRIDS TO REFLECT LATEST MESONET OBSERVATIONS...OTHERWISE REST OF FORECAST FOR TONIGHT STILL LOOKS RIGHT ON TARGET. AS OF 350 PM EST MONDAY... TRICKY FCST OVERNIGHT IN REGARDS TO THE AMOUNTS AND LOCATIONS OF VERY LIGHT PCPN AS A WEAK UPPER WAVE PASSES OVER THE DEEPENING COLD AIR DAMMING WEDGE AS COLD SFC HIGH PRESSURE SPILLS DOWN FROM THE NORTH. MODEL GUIDANCE ALL QUITE DIFFERENT WITH MAIN OPERATIONAL NCEP MODELS TRENDING UPWARD SOMEWHAT WITH AS MUCH AS A QUARTER TO TWO THIRDS OF AN INCH LIQUID EQUIV...MAINLY OVER THE WESTERN PORTIONS. EVEN ORIGINALLY DRIER GFS NOW AS MUCH AS FOUR TENTHS OF AN INCH OVER THE ALLEGHANY HIGHLANDS. MEANWHILE CONVECTIVE-ALLOWING MODELS GENERALLY LESS THAN TWO TENTHS OF AN INCH. AM LEANING ON THE LIGHT SIDE OF THE QPF OPTIONS...MORE IN LINE WITH IDEA OF MOST OF THE HRRR RUNS...AND POSSIBILITY THAT MORE OF THE PCPN ACTUALLY ENDS UP BACK ACROSS THE FOOTHILLS AND PIEDMONT AGAIN. AM LEAVING SOME VERY LOW LIKELY POPS FOR TONIGHT ACROSS PARTS OF THE MOUNTAINS...WITH HIGHER CHANCE POPS NOW ACROSS THE FOOTHILLS. THE ISSUE OF MOISTURE DEPTH IS STILL CONCERN AS WELL...AND WHILE I DID NOT INCLUDE ANY DRIZZLE IN THE GRIDS...THERE COULD VERY WELL BE PERIODS OF TIME AND PORTIONS OF THE AREA WHERE WE SEE MORE DRIZZLE DUE TO LACK OF ICE CRYSTAL GROWTH ALOFT. THIS WOULD CUT DOWN ON ANY OF THE ALREADY LIGHT SNOW ACCUMS IF AND WHERE THIS HAPPENS. WARM NOSE DOES NOT SEEM TO BE PRESENT IN ANY MODEL SOUNDINGS...SO GOING WITH EITHER RAIN OR SNOW...AND SO SFC TEMPS WILL BE THE KEY TO THAT CHANGEOVER. AS FAR AS THE TEMPS GO...ALREADY GETTING COLDER THIS AFTERNOON THAN WE EARLIER ANTICIPATED...AND SOME HIGHER ELEVATIONS HAVE REPORTS SOME VERY LIGHT SNOW. THUS LOWERED TEMPS THROUGH EVENING AND OVERNIGHT A FEW DEGREES FROM PREVIOUS FORECAST WHERE WEDGE IS EXPECTED TO BE THE STRONGEST...AND THIS RESULTS IN A SLIGHTLY EARLIER CHANGEOVER FROM LIGHT RAIN TO LIGHT SNOW...BUT EXCEPT FOR HIGHER ELEVATIONS...THIS WILL STILL BE AFTER MIDNIGHT. BOTTOM LINE IS ONLY VERY LIGHT AMOUNTS OF SNOW ACCUM EXPECTED LATE TONIGHT AND IN THE EARLY MORNING HOURS TUESDAY...AND IT WILL LIKELY HAVE TROUBLE STICKING AS WELL EXCEPT FOR HIGHEST ELEVATIONS. HAVE DUSTING TO LESS THAN AN INCH GENERALLY NORTH OF U.S. 460...AND DOWN THE BLUE RIDGE TO NEAR MEADOWS OF DAN. MAYBE AN INCH TO ALMOST TWO ALONG HIGHEST RIDGES OF ALLEGHANY HIGHLANDS AND ALONG BLUE RIDGE PARKWAY NORTH OF PEAKS OF OTTER. MOST ROADS NOT EXPECTED TO SEE ANY ACCUMULATION. ANY LINGERING PCPN EVAPORATES QUICKLY BY MIDDAY TUESDAY AS SHORT WAVE PASSES BY AND DRIER AIR FROM NORTH CONTINUES TO FILTER IN. WESTERLY FLOW AT RIDGE TOP LEVEL DEVELOPS BUT VERY WEAK FLOW AND LITTLE MOISTURE TO WORK WITH SO NO ISSUES WITH ANY UPSLOPE SNOW SHOWERS IN FAR WEST IT APPEARS. MAX TEMPS MAY BE TRICKY WITH SOME SUNSHINE LATE IN THE DAY...BUT THIS COULD BE TOO LATE FOR LOW SUN ANGLE TO HAVE MUCH IMPACT...SO FOR NOW GOING ON COLD SIDE OF GUIDANCE WITH ONLY ABOUT A 5-7 DEGREE RISE FROM OVERNIGHT LOWS. ABOVE FREEZING BY LATE MORNING SO ANY MINOR AMOUNTS OF SNOW THAT DOES FALL WILL BE GONE BY NOON MOST LIKELY. FINALLY...COLD WEDGE WILL KEEP SOME AREAS OF FOG AND LOW CEILINGS AROUND...MOST ESPECIALLY NEAR THE BLUE RIDGE...BUT ALSO SOME OF THE MTN VALLEYS AS WELL...SO BLANKED THE FOOTHILLS AND WESTWARD WITH PATCHY FOG THROUGH TOMORROW MORNING IN THE FORECAST GRIDS BUT THIS MAY LINGER THROUGH MUCH OF THE DAY IN SPOTS UNTIL THE WEAK WESTERLY FLOW CAN PUSH EAST. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 200 PM EST MONDAY... A LARGE AREA OF HIGH PRESSURE WILL BUILD SOUTH FROM THE ROCKIES LATE TUESDAY...THEN INTO THE SOUTHEAST U.S. BY THURSDAY EVENING KEEPING DRY WEATHER FOR OUR AREA DURING THIS PORTION OF THE FORECAST. ADJUSTED TEMPS DOWN A FEW DEGREES WEDNESDAY MORNING AND WEDNESDAY AFTERNOON UNDER GOOD COLD AIR ADVECTION. BY THURSDAY MORNING MODELS ARE IN GOOD AGREEMENT THAT SFC HIGH NOSES INTO OUR AREA ALLOWING VALLEY WINDS TO DIMINISH. THIS COMBINED WITH THE DRY AIR MASS IN PLACE SHOULD ALLOW TEMPS TO DROP BELOW GUIDANCE VALUES. THE EXCEPTION WILL BE ON THE RIDGETOPS WHERE 850MB WINDS WILL KEEP TEMPS WARMER. HEIGHTS RISE ON THURSDAY AS AN UPPER RIDGE BEGINS TO BUILD IN THE CENTRAL U.S. IN ADVANCE OF A SOUTHWEST U.S. UPPER LOW. THIS...COMBINED WITH DOWNSLOPING WINDS...SHOULD ALLOW FOR A NICE RECOVERY IN TEMPS THURSDAY. WENT A DEGREE OR TWO ABOVE GUIDANCE FOR HIGHS. ONLY OTHER CHANGE TO THE FORECAST WAS TO INCREASE THE WINDS ABOVE 3500 FEET WEDNESDAY AND THURSDAY AS A SWIFT MOVING NORTHERN STREAM SHORTWAVE PASSES THROUGH THE EASTERN GREAT LAKES THROUGH NEW ENGLAND DURING THIS TIME. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 235 PM EST MONDAY... DRY AND SEASONABLY COOL WEATHER IS EXPECTED OVER THE BLACKSBURG FORECAST AREA FRIDAY MORNING AS A WEAK SHORT WAVE IN NORTHERN STREAM SCOOTS EAST THROUGH NEW ENGLAND...WITH COOL HIGH PRESSURE BUILDING SOUTHWESTWARD IN ITS WAKE. HOWEVER...MUCH OF THE REST OF THE LONG TERM FORECAST FROM FRIDAY AFTERNOON INTO MONDAY APPEARS TO BE MUCH MORE UNCERTAIN...WITH SIGNIFICANT AND PERSISTENT DISPARITY EXISTING BETWEEN THE LONGER- TERM MODELS IN REFLECTING STRENGTH AND PLACEMENT OF NORTHERN STREAM...AND ITS INFLUENCE ON SOUTHERN STREAM CLOSED LOW SOUTH OF THE FOUR CORNERS AREA ON FRIDAY AFTERNOON THAT IS FORECAST TO GRADUALLY LIFT NORTHEAST AND FILL AS IT PROGRESSES FROM THE SOUTHERN PLAINS UP THROUGH THE OHIO VALLEY OVER THE WEEKEND. ECMWF MAINTAINS A MORE PERSISTENT CLOSED UPPER LOW THAT IS MUCH LESS AMPLIFIED...YET LESS PROGRESSIVE AND FURTHER SOUTH...RESULTING IN INCREASING ISENTROPIC LIFT AND RAIN MOVING INTO AT LEAST THE SOUTHWESTERN HALF OF THE BLACKSBURG FORECAST AREA BY/DURING FRIDAY AFTERNOON...BUT NOT ENDING UNTIL PASSAGE OF OPENING/WEAKENING UPPER TROF ON SUNDAY NIGHT. GFS...WHICH REFLECTS A MORE AMPLIFIED...YET EVENTUALLY MORE PROGRESSIVE AND NORTHERN SYSTEM PLACEMENT...HOLDS BACK RAIN SHIELD UNTIL SATURDAY DUE TO INFLUENCE OF LARGER AND STRONGER DRY SURFACE HIGH PRESSURE SYSTEM OVER NEW ENGLAND. GFS ALSO THE COLDER OF THE LONGER RANGE SOLUTIONS...SINCE STRONGER SURFACE RIDGE TO NORTHEAST WOULD LOCK COOL-WEDGE IN PLACE OVER THE BLACKSBURG FORECAST AREA. HOWEVER...BEING MORE PROGRESSIVE...RAIN EVENT ENDS A BIT EARLIER THAN ECMWF SOLUTION...ON SUNDAY AFTERNOON WITH PASSAGE OF UPPER TROF...BUT WITH PERHAPS SOME COLD ADVECTION UPSLOPE PRECIPITATION CONTINUING ACROSS THE WESTERN FLANKS OF THE APPALACHIANS UNTIL AROUND DAYBREAK MONDAY. BOTH MODELS HAVE BEEN INCONSISTENT IN TIMING AND PLACEMENT OF SYSTEM THOUGH THIS TIME FRAME FOR AT LEAST THE PAST SEVERAL RUNS...WHICH IS NOT ALL THAT SURPRISING CONSIDERING ACTIVE NORTHERN STREAM CLASHING WITH INITIALLY CLOSED AND STAGNANT SOUTHERN STREAM SYSTEM...SO MODEL BLEND/ENSEMBLE APPROACH BEST TO APPLY FOR LONG TERM FORECAST UNTIL CONFIDENCE INCREASES IN MOVING TOWARD ANY PARTICULAR SOLUTION. NEITHER MODEL INDICATING THAT THICKNESSES WILL BE ESPECIALLY CRITICAL FOR P-TYPE ISSUES...MEANING A MAINLY WET RATHER THAN WHITE FORECAST OVER THE WEEKEND. HOWEVER...IF COLDER GFS SOLUTION VERIFIES...THICKNESSES MAY BE CLOSE ENOUGH TO CRITICAL VALUES NORTH OF HIGHWAY 64 TO WARRANT AT LEAST A NOMINAL INSERTION OF A P-TYPE MIX DURING TIME OF PRECIPITATION ONSET...AND PERHAPS FOLLOWING PASSAGE OF MAIN SYSTEM IN THE NORTHWESTERN MOUNTAINS ON SUNDAY NIGHT PROVIDED THAT POST FRONTAL COLD ADVECTION IS SUFFICIENTLY STRONG. REGARDLESS OF TIMING AND PLACEMENT DIFFERENCES...ALL LONGER RANGE MODELS INDICATE THAT MONDAY WILL BE DRY FOLLOWING PASSAGE OF THE MAIN UPPER SYSTEM...WITH ANY ADDITION SOUTHERN STREAM ENERGY LIKELY TO BE DEFLECTED TO OUR SOUTH AS NORTHERN STREAM TROFING GRADUALLY STRENGTHENS AND AMPLIFIES FROM THE UPPER GREAT LAKES EAST INTO THE NORTHEASTERN PORTION OF THE NATION FROM MONDAY INTO THE MID WEEK PERIOD. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 1150 PM EST MONDAY... IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE AT ALL AIRPORTS THROUGH AT LEAST TONIGHT...AND FOR WESTERN AIRPORTS EVEN INTO EARLY PART OF TUESDAY...UNDER THE INFLUENCE OF COLD AIR DAMMING WHICH IS ONLY STRENGTHENING WITH TIME. ALL AIRPORTS EXCEPT FOR KDAN SHOULD SEE SOME VERY LIGHT RAIN CHANGE TO LIGHT SNOW OVERNIGHT...BUT NOT EXPECTED TO STICK MUCH AT ALL EXCEPT FOR THE HIGHER ELEVATION AIRPORTS SUCH AS KLWB...AND KBCB. NOT SURE IT WILL BE COLD ENOUGH TO REALLY ACCUMULATE AT KBLF AND KROA OR KLYH. KDAN LIKELY WILL NOT EVEN SEE CHANGEOVER. IN ANY CASE...SNOW AMOUNTS WOULD ONLY APPROACH AN INCH IN THE WORSE-CASE SCENARIO. LOW CONFIDENCE FOR WHEN CONDITIONS MAY BEGIN TO BREAK OUT AND LIFT ON TUESDAY. MORE CONFIDENT THAT KROA...KLYH AND KDAN WILL IMPROVE TO VFR BY TUESDAY AFTERNOON AS DRIER AIR CONTINUES TO FILTER DOWN FROM NORTH. CLEARING WILL CONTINUE IN THE AFTERNOON AND EVENING. EVEN MOUNTAIN TAF SITES WILL IMPROVE TO VFR. EXTENDED DISCUSSION... A LARGE AREA OF HIGH PRESSURE WILL START TO NOSE INTO THE AREA FROM THE WEST LATER TUESDAY INTO WEDNESDAY. VFR WILL THEN PREVAIL THROUGH AT LEAST THURSDAY CONDITIONS DETERIORATE THE WEEKEND. THE NEXT LOW PRESSURE SYSTEM TO AFFECT THE AREA WILL COME FROM THE SOUTHWEST..DEVELOPING ALONG THE TEXAS GULF COAST FRIDAY...THEN MOVING NORTHEAST ACROSS THE MID ATLANTIC REGION FOR THE WEEKEND. THIS SYSTEM LOOKS LIKE IT WILL PRODUCE A MULTI-DAY PERIOD OF SUB-VFR CONDITIONS...BEGINNING AS EARLY AS FRIDAY NIGHT...AND LINGERING THROUGH SUNDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...SK NEAR TERM...SK/WERT SHORT TERM...PH LONG TERM...WERT AVIATION...AMS/WERT
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1020 AM EST TUE DEC 30 2014 .DISCUSSION... FRONTAL BNDRY JUST N OF THE I-4 CORRIDOR HAS STALLED DUE TO A STUBBORN H100-H70 HI PRES RIDGE OVER THE FL STRAITS. MRNG RAOBS SHOW DEEP MOISTURE AHEAD OF THE FRONT WITH PWAT VALUES BTWN 1.5"-1.8" AS KXMR-KTBW RESPECTABLY...BUT DECREASING EITHER SIDE OF THE BNDRY TO 1.2" AT KJAX/KMFL. RUC ANALYSIS SHOWS RESPECTABLE MID/UPR LVL DYNAMIC SUPPORT ALONG THE FRNTL BNDRY OVER THE GOMEX...BUT LITTLE OVER CENTRAL FL. LATEST RADAR TREND REFLECTS THIS LACK OF SUPPORT AS AN AREA OF MODERATE RAIN THAT MOVED ONSHORE OVER TAMPA BAY HAS WEAKENED INTO A BROAD AREA OF LIGHT STRATIFORM RAIN AS IT APPROACHED THE FL TURNPIKE. WHILE THE FRONT HAS STALLED...RUC SHOWS AN H100-H70 N/NW SURGE OVER THE LWR MS VALLEY THAT SHOULD GIVE IT THE PUSH IT NEEDS TO PLOW THE RIDGE AXIS OUT OF THE FL STRAITS LATER TODAY. LITTLE IN THE WAY OF SFC HEATING N OF SR60 AS CLOUD COVER ENTRENCHED WITHIN THE FRONTAL TROF STREAMS ACRS CENTRAL FL. PRECIP WILL BE SPOTTY AT BEST WITH QPF VALUES AOB 0.10". FURTHER S...WHILE SUNNY SKIES AND SFC DEWPOINTS IN THE M/U60S NORMALLY WOULD SUGGEST THE THREAT OF TSRAS...THE LACK OF ANY SIG DYNAMIC SUPPORT COUPLED WITH A LINGERING SUBSIDENCE INVERSION IN THE H85-H70 LYR (LAPSE RATES BTWN 3.0-4.0C/KM) SUGGESTS THE SRN CWA WILL REMAIN DRY. WILL KNOCK A FEW DEG OF MAX TEMPS FROM BREVARD/OSCEOLA NWD...ALSO WILL SHAVE POPS BACK A TOUCH ARND LAKE OKEECHOBEE. && .AVIATION...THRU 31/12Z SFC WNDS: THRU 30/20Z...W/SW 5-8KTS BCMG N. AFT 30/20Z...N 4-7KTS. VSBYS/WX: THRU 30/20Z...N OF KTIX-KISM...PDS OF MVFR IN -RA/BR...S OF KTIX-KISM PREVAILING VFR WITH LCL IFR IN BR/FG ENDING BY 30/16Z. BTWN 30/20Z-31/04Z...N OF KTIX-KISM VFR...S OF KTIX-KISM PDS OF MVFR IN -RA/BR. AFT 31/04Z...AREAS MVFR BR WITH LCL LIFR FG N OF KDAB-KISM. CIGS: THRU 30/17Z...N OF KTIX-KISM PREVAILING BTWN FL015-020 WITH AREAS LIFR BLO FL005...S OF KTIX-KISM PREVAILING AOA FL120 WITH LCL LIFR BLO FL004. BTWN 30/17Z-31/04Z...PREVAILING FL040-060 WITH AREAS MVFR FL020-030. AFT 31/04Z...PREVAILING MVFR FL020-030...N OF KTIX-KISM AREAS LIFR BLO FL005...S OF KTIX-KISM LCL IFR BTWN FL005-009. && .MARINE... RUC ANALYSIS SHOWS TEH FRONTAL TROF EXTENDING FROM THE CENTRAL GOMEX TO THE NC OUTER BANKS. LATEST SFC OBS INDICATE THE FRONT HAS PUSHED S OF ST. AUGUSTINE BUT REMAINS N OF BUOY009...FOG/CALM WINDS ALONG THE COAST BTWN PALM COAST AND NEW SMYRNA BEACH AS OF 14Z SUGGEST THE BNDRY IS IN THE VCNTY OF THE VOLUSIA/FLAGLER COUNTY LINE. DESPITE A STUBBORN RIDGE AXIS OVER THE FL STRAITS...THE FRONT WILL PUSH THRU CENTRAL FL THRU SUNSET...FORCING SFC/BNDRY LYR WINDS TO VEER FROM W/SW TO DUE NORTH...GENERALLY BTWN 10-15KTS. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE...INCREASING TO 2-3FT NEARSHORE AND 3-4FT OFFSHORE AS WINDS SWING ARND TO THE N. NO SIG CHANGES. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1010 AM EST TUE DEC 30 2014 .UPDATE (REST OF TODAY THROUGH WEDNESDAY)... 15Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW MUCH OF THE NATION UNDER A BROAD LONGWAVE TROUGH. THE MOST ENERGETIC FEATURE WITHIN THIS TROUGH IS A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE INTERMOUNTAIN WEST WHICH IS PROGGED BY ALL THE NUMERICAL GUIDANCE TO BECOME A LARGE CUTOFF LOW OVER THE SOUTHWESTERN STATES BEFORE EJECTING EASTWARD ACROSS THE SOUTHERN/CENTRAL PLAINS LATER IN THE WEEK. OUR FORECAST AREA RESIDES WITHIN A ZONE OF DEEP LAYER SOUTHWEST FLOW BETWEEN THE LONGWAVE TROUGH AND AND WEST-EAST ORIENTED RIDGE ACROSS THE NORTHWEST CARIBBEAN. A PLUME OF SOUTHERN STREAM MOISTURE IS STILL IN WV IMAGERY RIDGING THIS FLOW OVER THE EASTERN GULF OF MEXICO AND FL PENINSULA. AT THE SURFACE...A WEAK COLD FRONT HAS ENTERED THE NORTHERN FLORIDA PENINSULA AND IS NOW STRETCHED ACROSS THE NATURE COAST ON A SLOW TREK SOUTHWARD THROUGH THE DAY. REGIONAL RADARS CONTINUE TO SHOW AN EXPANSION OF THE SHOWERS ALONG AND AHEAD OF THIS BOUNDARY...AND THIS IS LIKELY RELATED TO SOME ADDED SYNOPTIC SUPPORT FOR LIFT ASSOCIATED WITH A WEAK/SUBTLE PASSING SHORTWAVE ALOFT OVER THE NE GULF OF MEXICO. HAVE SUBSTANTIALLY INCREASED RAIN CHANCES FOR THE MORNING THROUGH WEST-CENTRAL FLORIDA AS A SOGGY NEXT FEW HOURS NOW APPEARS LIKELY. FORECAST GRIDS AND TEXT PRODUCTS HAVE BEEN UPDATED. THE RAIN IS ALSO HELPING LIFT SOME OF THE DENSE FOG SEEN AROUND THE AREA. FOR LOCATIONS SOUTH OF THE RAIN SHIELD...THE DENSE FOG IS HOLDING IN LONGER. JUST BEGINNING TO SEE THE EROSION OF THIS FOG DUE TO DIURNAL MIXING AND VISIBILITIES SHOULD BE IMPROVING QUICKLY INTO THE LATER MORNING HOURS. WITH ALL THIS IN MIND WILL ALLOW THE DENSE FOG ADVISORY TO EXPIRE AT 10AM...EVEN THOUGH A FEW SPOTS MAY STILL TECHNICALLY MEET CRITERIA FOR A BIT LONGER. USING THE LATEST HRRR FOR TIMING...THE FRONT STILL LOOKS TO ARRIVE AT THE I-4 CORRIDOR AROUND MIDDAY/EARLY AFTERNOON AND THEN SLOWLY SETTLE SOUTH TO NEAR PUNTA GORDA AROUND SUNSET. THE ORGANIZATION AND COVERAGE OF SHOWERS SHOULD BEGIN TO DIMINISH DURING THE SECOND HALF OF THE DAY AS THE SHORTWAVE INFLUENCE PASSES TO OUR EAST. HOWEVER...THE LOW LEVEL BOUNDARY FOCUS WILL STILL KEEP THE CHANCE FOR MORE SCT SHOWERS IN THE FORECAST. ALSO WITH THE FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...THE ACTUALLY BOUNDARY PASSAGE WILL NOT NECESSARILY END THE CHANCE FOR RAIN AS MANY OF THE GUIDANCE MEMBERS ARE INDICATING THE BOUNDARY WILL TAKE ON AN INCREASINGLY ANAFRONT CONFIGURATION BY LATER TODAY WHERE BETTER CHANCES FOR THE CLOUDS AND SHOWERS ARE ACTUALLY ALONG AND BEHIND THE BOUNDARY. FOR OUR SOUTHERN ZONES...FOG WILL BE LIFTING BY MIDDAY. YOUR SHOWERS CHANCES WILL BE INCREASING LATER THIS AFTERNOON AND INTO THE EVENING AS THE BOUNDARY MAKES IT WAYS SOUTHWARD. TONIGHT AND WEDNESDAY...THE FRONT STALLS AND BEGINS TO WASH OUT OVER THE SOUTHERN PENINSULA. THE GUIDANCE MEMBERS ARE ALL STARTING TO INDICATE THE DEVELOPMENT OF AN INVERTED TROUGH OVER THE GULF STREAM OFF THE FL EAST COAST DURING THIS TIME. THIS FOCUS ALONG WITH SOME SPEED CONVERGENCE ALONG THE COAST LOOKS TO BE ENOUGH FOR SHOWERS TO BEGIN MIGRATING ONSHORE. GOING TO HAVE TO LOOK AT THIS A BIT CLOSER WITH THE 12Z GUIDANCE AS SOME OF THESE SHOWERS MAY HAVE A CHANCE TO MIGRATE INLAND ENOUGH TO IMPACT PORTIONS OF POLK/HIGHLANDS COUNTIES ON WEDNESDAY. WOULD NOT BE A LOT OF RAIN...BUT WOULD NOT BE THE COMPLETELY DRY FORECAST CURRENTLY IN THE GRIDS. ELSEWHERE WEDNESDAY STILL LOOKS TO BE MAINLY DRY...HOWEVER PROB NOT A WHOLE LOT OF SUN AROUND...ESPECIALLY FOR THE I-4 CORRIDOR AND SOUTHWARD. && .AVIATION... VARYING CONDITIONS OUT THERE THIS MORNING WITH A MIX OF FOG AND RAIN. ALTHOUGH MANY STATIONS WILL NOT BE PREVAILING LIFR OR LOWER...PERIODS OF THESE LOW RESTRICTIONS WILL REMAIN POSSIBLE FOR ALL TERMINALS THROUGH THE MORNING HOURS. IMPROVEMENT WILL OCCUR FOR THE SECOND HALF OF THE DAY...HOWEVER AT LEAST PERIODS OF MVFR CONDITIONS SHOULD STILL BE EXPECTED. && .MARINE... AREAS OF SEA FOG REMAIN OVER THE WATERS THIS MORNING AHEAD OF AN APPROACHING COLD FRONT. THE FOG HAS BECOME LESS PREVALENT OVER THE PAST COUPLE OF HOURS...ESPECIALLY OVER TAMPA BAY AND THE GULF WATERS TO THE WEST OF THE BAY AS SHOWERS HAVE BEEN ONGOING THERE FOR SEVERAL HOURS. THE SEA FOG IS EXPECTED TO DISSIPATE BY LATE MORNING OR EARLY AFTERNOON AS THE FRONT SINKS SOUTHWARD. THERE WILL BE A CHANCE FOR SHOWERS THROUGH THE REST OF THE DAY AS WELL...WHICH COULD BRIEFLY REDUCE VISIBILITY OVER THE WATERS. && .PRELIMINARY POINT TEMPS/POPS... TPA 78 63 75 59 / 90 10 20 10 FMY 82 65 81 63 / 30 20 20 10 GIF 79 62 75 57 / 80 10 20 10 SRQ 79 63 76 60 / 70 10 20 10 BKV 78 59 74 53 / 60 10 10 10 SPG 77 65 74 60 / 90 10 20 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/AVIATION...MROCZKA MARINE...CARLISLE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
825 AM EST TUE DEC 30 2014 .UPDATE (REST OF TODAY THROUGH WEDNESDAY)... 13Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW MUCH OF THE NATION UNDER A BROAD LONGWAVE TROUGH. THE MOST ENERGETIC FEATURE WITHIN THIS TROUGH IS A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE INTERMOUNTAIN WEST WHICH IS PROGGED BY ALL THE NUMERICAL GUIDANCE TO BECOME A LARGE CUTOFF LOW OVER THE SOUTHWESTERN STATES BEFORE EJECTING EASTWARD ACROSS THE SOUTHERN/CENTRAL PLAINS LATER IN THE WEEK. OUR FORECAST AREA RESIDES WITHIN A ZONE OF DEEP LAYER SOUTHWEST FLOW BETWEEN THE LONGWAVE TROUGH AND AND WEST-EAST ORIENTED RIDGE ACROSS THE NORTHWEST CARIBBEAN. A PLUME OF SOUTHERN STREAM MOISTURE IS STILL IN WV IMAGERY RIDGING THIS FLOW OVER THE EASTERN GULF OF MEXICO AND FL PENINSULA. AT THE SURFACE...A WEAK COLD FRONT HAS ENTERED THE NORTHERN FLORIDA PENINSULA AND IS NOW STRETCHED ACROSS THE NATURE COAST ON A SLOW TREK SOUTHWARD THROUGH THE DAY. REGIONAL RADARS HAVE SHOWN A RAPID EXPANSION OF THE SHOWERS ALONG AND AHEAD OF THIS BOUNDARY DURING THE PAST FEW HOURS...AND THIS IS LIKELY RELATED TO SOME ADDED SYNOPTIC SUPPORT FOR LIFT ASSOCIATED WITH A WEAK/SUBTLE PASSING SHORTWAVE ALOFT OVER THE NE GULF OF MEXICO. HAVE SUBSTANTIALLY INCREASED RAIN CHANCES FOR THE MORNING THROUGH WEST-CENTRAL FLORIDA AS A SOGGY NEXT FEW HOURS NOW APPEARS LIKELY. FORECAST GRIDS AND TEXT PRODUCTS HAVE BEEN UPDATED. THE RAIN IS ALSO HELPING LIFT SOME OF THE DENSE FOG SEEN AROUND THE AREA AND WILL BE MAKING DECISIONS ON WHAT TO DO WITH THE DENSE FOG ADVISORY IN THE NEXT COUPLE OF HOURS. USING THE LATEST HRRR FOR TIMING...THE FRONT LOOKS TO ARRIVE THE I-4 CORRIDOR AROUND MIDDAY AND THEN SLOWLY SETTLE SOUTH TO NEAR PUNTA GORDA AROUND SUNSET. THE ORGANIZATION AND COVERAGE OF SHOWERS SHOULD BEGIN TO DIMINISH DURING THE SECOND HALF OF THE DAY AS THE SHORTWAVE INFLUENCE PASSES TO OUR EAST. HOWEVER...THE LOW LEVEL BOUNDARY FOCUS WILL STILL KEEP THE CHANCE FOR MORE SCT SHOWERS IN THE FORECAST. ALSO WITH THE FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...THE ACTUALLY BOUNDARY PASSAGE WILL NOT NECESSARILY END THE CHANCE FOR RAIN AS MANY OF THE GUIDANCE MEMBERS ARE INDICATING THE BOUNDARY WILL TAKE ON AN INCREASINGLY ANAFRONT CONFIGURATION BY LATER TODAY WHERE BETTER CHANCES FOR THE CLOUDS AND SHOWERS ARE ACTUALLY ALONG AND BEHIND THE BOUNDARY. FOR OUR SOUTHERN ZONES...A COUPLE MORE HOURS WITH THE FOG AND THEN WE SHOULD BEGIN TO BURN IT OFF. YOUR SHOWERS CHANCES WILL BE INCREASING THIS AFTERNOON AND INTO THE EVENING AS THE BOUNDARY MAKES IT WAYS SOUTHWARD. TONIGHT AND WEDNESDAY...THE FRONT STALLS AND BEGINS TO WASH OUT OVER THE SOUTHERN PENINSULA. THE GUIDANCE MEMBERS ARE ALL STARTING TO INDICATE THE DEVELOPMENT OF AN INVERTED TROUGH OVER THE GULF STREAM OFF THE FL EAST COAST DURING THIS TIME. THIS FOCUS ALONG WITH SOME SPEED CONVERGENCE ALONG THE COAST LOOKS TO BE ENOUGH FOR SHOWERS TO BEGIN MIGRATING ONSHORE. GOING TO HAVE TO LOOK AT THIS A BIT CLOSER WITH THE 12Z GUIDANCE AS SOME OF THESE SHOWERS MAY HAVE A CHANCE TO MIGRATE INLAND ENOUGH TO IMPACT PORTIONS OF POLK/HIGHLANDS COUNTIES ON WEDNESDAY. WOULD NOT BE A LOT OF RAIN...BUT WOULD NOT BE THE COMPLETELY DRY FORECAST CURRENTLY IN THE GRIDS. ELSEWHERE WEDNESDAY STILL LOOKS TO BE MAINLY DRY...HOWEVER PROB NOT A WHOLE LOT OF SUN AROUND...ESPECIALLY FOR THE I-4 CORRIDOR AND SOUTHWARD. && .AVIATION... VARYING CONDITIONS OUT THERE THIS MORNING WITH A MIX OF FOG AND RAIN. ALTHOUGH MANY STATIONS WILL NOT BE PREVAILING LIFR OR LOWER...PERIODS OF THESE LOW RESTRICTIONS WILL REMAIN POSSIBLE FOR ALL TERMINALS THROUGH THE MORNING HOURS. IMPROVEMENT WILL OCCUR FOR THE SECOND HALF OF THE DAY...HOWEVER AT LEAST PERIODS OF MVFR CONDITIONS SHOULD STILL BE EXPECTED. && .MARINE... DENSE SEA FOG WILL BE LOCATED OVER THE NEAR SHORE COASTAL WATERS SOUTH OF THE COLD FRONT. AS THE COLD FRONT GRADUALLY SINKS SOUTH TODAY...THE AREA OF SEA FOG WILL BE SINK SOUTH AND DECREASE IN AREAL COVERAGE...DISSIPATING BY LATE TODAY. WEAK HIGH PRESSURE WILL BUILD OVER THE WATERS BEHIND THE FRONT THROUGH THE REMAINDER OF THE WEEK. WINDS WILL BE LESS THAN 15 KNOTS WITH SEAS LESS THAN 4 FEET THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... TPA 78 63 75 59 / 90 10 20 10 FMY 82 65 81 63 / 30 20 20 10 GIF 79 62 75 57 / 80 10 20 10 SRQ 79 63 76 60 / 70 10 20 10 BKV 78 59 74 53 / 60 10 10 10 SPG 77 65 74 60 / 90 10 20 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR COASTAL CHARLOTTE-COASTAL CITRUS-COASTAL HERNANDO- COASTAL HILLSBOROUGH-COASTAL LEE-COASTAL LEVY-COASTAL MANATEE-COASTAL PASCO-COASTAL SARASOTA-DESOTO-HARDEE- HIGHLANDS-INLAND CHARLOTTE-INLAND HERNANDO-INLAND HILLSBOROUGH-INLAND LEE-INLAND MANATEE-INLAND PASCO- INLAND SARASOTA-PINELLAS-POLK. GULF WATERS...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-CHARLOTTE HARBOR AND PINE ISLAND SOUND-ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM. && $$ UPDATE/AVIATION...MROCZKA MARINE...CARLISLE
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
614 AM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TODAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP SATURDAY AND LIFT NORTH OF THE REGION BY SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MESOSCALE UPDATE...THE DENSE FOG IN THE SAVANNAH AND BEAUFORT AREAS HAS LIFTED BACK INTO A VERY LOW STRATUS DECK. WEBCAMS AND SURFACE OBSERVATIONS INDICATE VSBYS HAVE IMPROVED TO 1-2 MILES. HOWEVER...LOCALLY DENSE FOG IS STILL LIKELY NEAR BODIES OF WATER AND OTHER LOW LYING AREAS. AN AREA OF DENSE FOG IS TRYING TO NOSE INTO PARTS OF JENKINS-CANDLER-EVANS-TATTNALL AND BULLOCH. WITH SUNRISE APPROACHING...PREFER TO HANDLE THIS WITH A SPECIAL WEATHER STATEMENT. HOWEVER...A DENSE FOG ADV CAN NOT BE RULED OUT. SURFACE TROUGH/SECONDARY COLD SURGE IS WORKING ITS WAY SOUTH OF THE SOUTH SANTEE RIVER AND WILL CROSS THE I-26 CORRIDOR THROUGH SUNRISE. HIGHS WILL LIKELY OCCUR DAY TIME HIGHS WILL LIKELY OCCUR IN THE 7-9AM TIME FRAME BEFORE TEMPERATURES HOLD STEADY THEN POSSIBLY FALL. ADJUSTED HOURLY TEMPERATURES ACROSS THE CHARLESTON TRI- COUNTY AREA A BIT. TODAY...LOW CONFIDENCE FORECAST TODAY. THE COLD FRONT AND ASSOCIATED FRONTAL WAVE ARE NOW WELL OFFSHORE WITH A NORTHERLY LOW-LEVEL FLOW DOMINATING IN ITS WAKE. A WEAK POST FRONTAL SURFACE TROUGH DELINEATING A SURGE OF COOLER AIR WILL APPROACH THE CHARLESTON AREA BY SUNRISE...THE SAVANNAH AREA BY MID/LATE MORNING AND FINALLY CLEARING THE ALTAMAHA RIVER BY LATE AFTERNOON. MODELS SHOW A TRANSIENT HYBRID WEDGE SETTING UP ACROSS MAINLY THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA IN THE WAKE OF THE TROUGH AS 290K ISENTROPIC ASSENT BRIEFLY INTENSIFIES ATOP THE LOW- LEVEL POST FRONTAL WEDGING PATTERN. THIS PATTERN WILL ESSENTIALLY REINFORCE THE WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE THAT ARE ALREADY IN PLACE ACROSS THE LOWCOUNTRY AND COASTAL EMPIRE FOR A GOOD PORTION OF THE DAY. THE TEMPERATURE FORECAST IS PROVING TO BE EXTREMELY CHALLENGING AS A RESULT AND ASSUMES THE TRANSIENT WEDGE ACTUALLY DEVELOPS AS DEPICTED IN THE HIGHER RESOLUTION DATA SETS. DAILY HIGHS /7AM-6PM/ WILL LIKELY OCCUR BY MID-MORNING ACROSS THE CHARLESTON TRI-COUNTY AREA AND EARLY AFTERNOON ACROSS THE REMAINDER OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. TEMPERATURES WILL LIKELY HOLD STEADY OR SLOWLY FALL NORTH THE SAVANNAH RIVER AS THE WEDGE BRIEFING INTENSIFIES. HIGHS WILL RANGE MID 50S NORTH...UPPER 50/NEAR 60 CENTRAL TO THE LOWER-MID 60S SOUTH. UTILIZE A 30/30/30 BLEND OF RAP/H3R AND GLAMP DATA TO CONSTRUCT HOURLY TEMPERATURES. SINCE THIS IS A VERY LOW CONFIDENCE FORECAST...CHANGES--SOME POSSIBLY SIGNIFICANT--WILL LIKELY BE NEEDED THROUGHOUT THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... TONIGHT...THE TRANSIENT HYBRID WEDGE WILL QUICKLY BREAKDOWN THIS EVENING AS HIGH PRESSURE FINALLY BRIDGES THE SOUTHERN APPALACHIANS AND BECOMES MORE DOMINATE ACROSS THE SOUTHEAST STATES. A GOOD BIT OF CLOUD COVER WILL LINGER THROUGH THE NIGHT WITH THE POTENTIAL FOR SOME CLEARING TO OCCUR ACROSS THE NORTH AFTER 3 AM. WILL HAVE TO WATCH FOR SOME FOG TO DEVELOP AFTER MIDNIGHT...BUT THIS DOES NOT LOOK SIGNIFICANT AT THIS TIME. LOWS WILL RANGE FROM THE MID- UPPER 30S INTERIOR NORTH WHERE THE BETTER CHANCES FOR CLEARING WILL OCCUR WITH UPPER 30S TO LOWER 40S ELSEWHERE...EXCEPT MID 40S ALONG THE GEORGIA COAST WHERE ONSHORE WINDS WILL MODERATE TEMPERATURES A BIT. WEDNESDAY AND THURSDAY...EXPANSIVE SURFACE HIGH PRESSURE WILL BE GRADUALLY WEAKENING AS IT SLIPS TOWARD THE EAST COAST UNDER RELATIVELY ZONAL FLOW ALOFT. EXPECT DRY CONDITIONS TO PREVAIL WEDNESDAY AND THURSDAY WITHIN THIS PATTERN. TEMPERATURES WEDNESDAY WILL BE A FEW DEGREES COOLER THAN NORMAL...PEAKING IN THE MID TO UPPER 50S DURING THE AFTERNOON AND FALLING INTO THE LOW 30S NORTH TO UPPER 30S COAST AND SOUTH OVERNIGHT. NORTH FLOW WEAKENS ON THURSDAY AS THE CENTER OF THE SURFACE HIGH PASSES DIRECTLY OVER THE REGION...AND WITH SUBTLE RIDGING BUILDING UP FROM THE BAHAMAS...HIGH TEMPERATURES WILL MODERATE TOWARD SEASONAL NORMALS IN THE UPPER 50S TO LOWER 60S. A GRADUALLY IMPROVING TAP INTO GULF MOISTURE LATE THURSDAY WILL SUPPORT INCREASING CLOUDS...WITH LOW TEMPERATURES A FEW DEGREES MILDER IN THE UPPER 30S INLAND TO LOW 40S CLOSER TO THE COAST. FRIDAY...AN UPPER LEVEL CUT OFF LOW WILL MOVE FROM THE SOUTHWEST STATES INTO THE SOUTHERN PLAINS...PROVIDING THE ENERGY TO DEVELOP A WAVE OF LOW PRESSURE ACROSS THE WESTERN GULF LATE IN THE DAY. THE SOUTHEAST STATES WILL REMAIN ON THE PERIPHERY OF ATLANTIC HIGH PRESSURE...WHERE SHORTWAVE ENERGY TRACKING UP FROM THE GULF OF MEXICO WILL SUPPORT THE GRADUAL AMPLIFICATION OF A COASTAL TROUGH. NUMERICAL MODEL SOLUTIONS ARE INDICATING SUFFICIENT ISENTROPIC ASCENT BETWEEN THE COASTAL TROUGH AND A DEVELOPING INLAND WEDGE TO GENERATE ISOLATED TO SCATTERED RAIN...WITH BEST COVERAGE ACROSS NORTHERN AND INLAND AREAS. TEMPERATURES COULD BE A DEGREE OR TWO COOLER THAN THE PREVIOUS DAY GIVEN THE INCREASING CLOUD COVER...YET STILL RANGE NEAR SEASONAL NORMALS IN THE UPPER 50S TO LOW 60S. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... FRIDAY NIGHT THROUGH SUNDAY...A TRANSIENT INLAND WEDGE/COASTAL TROUGH PATTERN WILL BE IN PLACE THROUGH EARLY SATURDAY...BEFORE THE COASTAL TROUGH QUICKLY LIFTS NORTH OF THE REGION AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. THE CUT OFF LOW ACROSS THE SOUTHERN PLAINS WILL DAMPEN AND LIFT NORTHEAST INTO THE OHIO VALLEY ON SATURDAY. THE ASSOCIATED SURFACE LOW WILL PULL INTO THE NEW ENGLAND STATES SUNDAY...WITH ITS TRAILING COLD FRONT PROGRESSING THROUGH THE MID ATLANTIC AND SOUTHEAST STATES BY SUNDAY AFTERNOON. HIGH TEMPERATURES WILL SURGE INTO THE 60S TO AROUND 70 DEGREES SATURDAY AND SUNDAY WITHIN WARM SOUTHERLY FLOW AHEAD OF THE FRONT...WHILE SCATTERED SHOWERS ARE POSSIBLE SATURDAY THROUGH SUNDAY AFTERNOON. PREFER TO REMAIN RATHER CONSERVATIVE WITH RAIN CHANCES AT THIS POINT...CONSIDERING THE SOUTHERN END OF THE FRONT WILL RUN INTO THE PERIPHERY OF THE SUBTROPICAL RIDGE AND BECOME PARALLEL TO FLOW ALOFT. SUNDAY NIGHT THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BUILD IN THE WAKE OF THE DEPARTING COLD FRONT EARLY NEXT WEEK...EVENTUALLY SETTLING TO THE NORTH OF THE AREA. RAIN FREE CONDITIONS WILL PREVAIL. TEMPERATURES ARE EXPECTED TO RETURN TO SEASONAL NORMALS...POSSIBLY COOLER IF A WEDGE PATTERN CAN SET UP TOWARD THE END OF THE FORECAST PERIOD. && .AVIATION /11Z TUESDAY THROUGH SATURDAY/... CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS THROUGH 14-15Z WITH CIGS RISING THEREAFTER. EXPECT MVFR CIGS TO RETURN TO KSAV BY 16Z WHICH WILL REMAIN IN PLACE THROUGH THE REMAINDER OF THE 12Z TAF PERIOD. AT KCHS...CIGS WILL BE SLOWER TO RISE WITH IFR CIGS RETURNING BY 17-18Z. THESE CONDITIONS WILL LINGER THROUGH 12Z WEDNESDAY. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL WEDNESDAY AND THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TODAY...CEILINGS OF 100 FT AT THE HILTON HEAD AIRPORT AND WEBCAMS IN THE SAVANNAH RIVER AS WELL AS TYBEE ISLAND SUGGEST SEA FOG IS IN PLACE ACROSS THE COASTAL WATERS THIS MORNING. IT IS UNCLEAR EXACTLY HOW WIDESPREAD THE FOG IS...BUT RAP VISIBILITIES DATA SUGGEST ITS PROBABLY PRETTY WIDESPREAD. WFO JAX RECENTLY RELAYED THAT THE BAR PILOTS OUT OF SAINT SIMMONS ARE REPORTING IMPROVED VSBYS OVER THE PAST HOUR...BUT THE SHELF WATERS OFF TYBEE ISLAND ARE SEVERAL DEGREES COOLER. PREFER TO HOLD THE MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE AND BEAUFORT COUNTY WATERS UNTIL 8 AM...OR AT LEAST UNTIL CONDITIONS CAN BE BETTER EVALUATED ON COASTAL WEBCAMS AS THE SUN RISES. OTHERWISE...NORTH WINDS WILL INCREASE TO 10-15 KT TODAY WITH SEAS 1-3 FT. TONIGHT...WINDS WILL INCREASE A BIT AS THE PRESSURE GRADIENT INDUCED BY HIGH PRESSURE BUILDING IN FROM THE WEST TIGHTENS. EXPECT WINDS OF 15-20 KT WITH SEAS 2-3 FT NEARSHORE...4-5 FT OFFSHORE. WEDNESDAY THROUGH SATURDAY...THE PRESSURE GRADIENT WILL REMAIN RELATIVELY TIGHT INTO WEDNESDAY MORNING ON THE PERIPHERY OF HIGH PRESSURE BUILDING FROM THE WEST. MARGINAL SMALL CRAFT ADVISORY WINDS IN GUSTS TO 25 KT COULD LINGER ACROSS THE OFFSHORE GEORGIA WATERS...BEFORE CONDITIONS SLOWLY IMPROVE AS THE DAY PROGRESSES. THE SURFACE HIGH WILL THEN STEADILY TRACK EAST AND ALLOW THE GRADIENT TO RELAX TOWARD THE END OF THE WEEK. A COASTAL TROUGH WILL DEVELOP LATE FRIDAY INTO SATURDAY...WITH INCREASING SOUTHERLY FLOW IN IT WAKE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR AMZ352-354. && $$ ST
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
951 AM EST TUE DEC 30 2014 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 304 AM EST TUE DEC 30 2014 IN THE NEAR TERM PERIOD...THE FOCUS WILL BE ON THE COOL DOWN AS ARCTIC HIGH PRESSURE STRENGTHENS OVER WESTERN CANADA. MUCH COLDER AIR WILL SPILL INTO PORTIONS OF THE CONTINENTAL U.S. AS A RESULT. HOWEVER...NO PRECIPITATION IS EXPECTED UNTIL THE EXTENDED PERIOD WHEN A CUT OFF LOW OVER THE DESERT SOUTHWEST MAKES ITS PROGRESSION ACROSS THE PLAINS...AND INTO CENTRAL INDIANA. TIMING AND TRACKING INCONSISTENCIES ARE MAKING IT DIFFICULT TO PINPOINT PRECIP TYPE AT THIS TIME...BUT EARLY INDICATIONS ARE SHOWING MIXED PRECIPITATION FOR MOST OF FRIDAY AND SATURDAY. PRECIP WILL END FROM WEST TO EAST ON SUNDAY...AND THE REMAINDER OF THE EXTENDED FORECAST WILL BE DRY AS FLOW ALOFT BECOMES MORE ZONAL ON MONDAY. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 950 AM EST TUE DEC 30 2014 FLURRIES WILL BE REMOVED FROM THE NORTHWEST. EVEN IN CLEAR AIR MODE THE RADARS UPSTREAM DONT SHOW ANYTHING AND THE HRRR DOESNT INTRODUCE ANYTHING. OTHER ELEMENTS OF THE EARLIER FORECAST ARE WORKING WELL BASED ON THE LATEST OBSERVATIONS.&& .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 410 AM EST MON DEC 30 2014 THERE IS BETTER AGREEMENT BETWEEN THE MODELS AS THEY ALL BRING PRECIPITATION NORTH ACROSS OUR ENTIRE REGION FRIDAY NIGHT THROUGH SATURDAY. PREVIOUSLY THE EURO ONLY BROUGHT IT INTO OUR SOUTHERN AREAS...WHILE MOST OTHER MODELS BROUGHT IT FARTHER NORTH. WITH THE EXCEPTION OF THE NAM ALL MODELS HAVE TRENDED A LITTLE SLOWER IN NOT BEGINNING PRECIPITATION UNTIL FRIDAY NIGHT. WILL GO ALONG WITH THIS SCENARIO AND KEEP ALL BUT THE FAR SOUTH DRY UNTIL FRIDAY NIGHT. PRECIPITATION WILL BE THE MAIN ISSUE FRIDAY NIGHT AND SATURDAY AS MODELS PULL WARMER NORTH INTO OUR REGION. BUFKIT SOUNDINGS INDICATE LOW CHANCES OF SNOW ACROSS OUR NORTH AND FREEZING PRECIPITATION SOUTH EARLY FRIDAY NIGHT AND WITH THICKNESS AND TEMPERATURES RISING SLOWLY OVERNIGHT WHICH SHOULD ALLOW CHANCES OF FREEZING RAIN TO SPREAD NORTH BY SATURDAY MORNING AND THEN PRECIPITATION BEING MOSTLY RAIN SATURDAY AFTERNOON. ALL MODELS INDICATE QUITE A BIT OF PRECIPITATION AROUND SATURDAY AND WENT WITH HPC PROGS WHICH INDICATED LIKELY POPS CENTRAL AND SOUTH SATURDAY. AFTER LOW PRESSURE GOES BY...MODELS INDICATE A CHANGEOVER BACK TO LIGHT SNOW OR FLURRIES SATURDAY NIGHT WITH RETURN OF COLDER AIR. WILL ALSO MENTION SLIGHT CHANCE OF SNOW SHOWERS WITH MIXED PRECIP FAR SOUTHEAST SUNDAY MORNING AND THEN DRY AFTER THAT AS COLD HIGH PRESSURE BUILDS BACK IN. MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING AS TEMPERATURES WILL BE NON-DIURNAL. OTHERWISE...MADE ONLY MINOR TWEAKS TO A MOS BLEND ON TEMPERATURES MOST OTHER PERIODS. && .AVIATION /DISCUSSION FOR 301500Z KIND TAF UPDATE/... ISSUED AT 913 AM EST TUE DEC 30 2014 NOT MUCH CHANGE TO PREVIOUS TAF FOR IND. STILL EXPECTING MAINLY VFR THROUGH THE PERIOD. BASED ON CURRENT OBSERVATIONAL TRENDS...DID STRENGTHEN THE WINDS SLIGHTLY OVER THE NEXT COUPLE HOURS AND ALSO DELAYED THE BACKING OF THE SURFACE WINDS. THE PREVIOUS DISCUSSION FOLLOWS... ISSUED AT 625 AM AM EST TUE DEC 30 2014 SATELLITE INDICATES BAND OF STRATO CU WITH DRY SECONDARY COLD FRONT WILL BE MOVING ACROSS TAF SITES TODAY. COULD BE A PERIOD OF MVFR CEILINGS AT KLAF THIS MORNING...OTHERWISE CEILINGS WILL BE JUST ABOVE 3 THOUSAND FEET AS BAND MOVES AS IT MOVES ACROSS. TIMING WILL BE MID MORNING TO MID AFTERNOON AT KLAF AND KHUF AND MAINLY THIS AFTERNOON AT KIND AND KBMG. OTHERWISE...VFR WITH FEW CU AND SCATTERED MID CLOUDS. MODEL SOUNDINGS INDICATE CLEARING SHOULD OCCUR LATE TONIGHT AS ARCTIC HIGH PRESSURE BUILDS INTO THE GREAT PLAINS. NORTH WINDS AROUND 10 KNOTS WILL BECOME NORTHWEST THIS AFTERNOON AND WEST AROUND 5 KNOTS LATE TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...JK SHORT TERM...TDUD LONG TERM...JH AVIATION...MRD/JH VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1001 AM CST TUE DEC 30 2014 .UPDATE... ISSUED AT 958 AM CST TUE DEC 30 2014 NO UPDATE PLANNED AT THIS TIME. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DON/T FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASURABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 700 AM CST TUE DEC 30 2014 BAND OF VFR CLOUD COVER DROPPING SOUTH. AT 13Z CLOUD BAND WAS CARRINGTON TO GRAND FORKS TO WASKISH. CLEARING BEHIND THIS CLOUD BAND IN NE ND...BUT SCATTERED CLOUDS REMAIN IN SOUTHEASTERN MANITOBA. TIMED CLOUD BAND SOUTHWARD THROUGH THE MORNING INTO FARGO THEN A FEW HOURS OF SCATTERED CLOUDS THEN CLEAR. SOME CIRRUS SPILLING SOUTH TONIGHT. WEST TO NORTHWEST WIND 10 TO 15 KTS TODAY INCREASING 15 TO 25 KTS IN NRN VALLEY OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016- 024-026>030-038-039-049-052>054. MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017- 022>024-027>032-040. && $$ UPDATE...DK SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
709 AM CST TUE DEC 30 2014 .UPDATE... ISSUED AT 700 AM CST TUE DEC 30 2014 NO UPDATES. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DONT FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASASUREABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 700 AM CST TUE DEC 30 2014 BAND OF VFR CLOUD COVER DROPPING SOUTH. AT 13Z CLOUD BAND WAS CARRINGTON TO GRAND FORKS TO WASKISH. CLEARING BEHIND THIS CLOUD BAND IN NE ND...BUT SCATTERED CLOUDS REMAIN IN SOUTHEASTERN MANITOBA. TIMED CLOUD BAND SOUTHWARD THROUGH THE MORNING INTO FARGO THEN A FEW HOURS OF SCATTERED CLOUDS THEN CLEAR. SOME CIRRUS SPILLING SOUTH TONIGHT. WEST TO NORTHWEST WIND 10 TO 15 KTS TODAY INCREASING 15 TO 25 KTS IN NRN VALLEY OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016- 024-026>030-038-039-049-052>054. MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017- 022>024-027>032-040. && $$ UPDATE...RIDDLE SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
921 AM CST TUE DEC 30 2014 .UPDATE... ISSUED A WINTER WEATHER ADVISORY FOR FREEZING DRIZZLE ON THE CAPROCK UNTIL NOON. MAY NEED TO EXTEND THIS AFTERNOON...AND IF SO WILL CONSIDER GOING THROUGH MUCH OF THE NIGHT. VERY COLD AIR MOVING SOUTHWARD SHOULD CHANGE FREEZING DRIZZLE MORE TO LIGHT SNOW AND PERHAPS LESS ICE ACCUMULATIONS BUT NOT CERTAIN AT THIS TIME. RMCQUEEN && .PREV DISCUSSION... /ISSUED 544 AM CST TUE DEC 30 2014/ UPDATE... KLBB 88D SHOWING THE EXPANSION OF VERY LIGHT REFLECTIVTY /ZERO TO MINUS 15 DBZ/ BTWN 1000 AND 5000 FT AGL AND LOWERING WITH TIME. THIS SHOULD BE THE PERIOD OF VERY LIGHT FLURRIES AND/OR FREEZING DRIZZLE ASSOCIATED WITH FRONTOGENTICAL FORCING. PER THE HRRR THIS PRECIP SHOULD SHIFT SWD WITH THE FORCING THROUGH THE MORNING. EXPECTATION IS IT SHOULD REMAIN TOO LIGHT CAUSE MUCH IN THE WAY OF DIFFICULTY THIS MORNING...BUT WILL CONTINUE TO MONITOR TRENDS. AVIATION... CIGS TO LOWER A BIT MORE DURING THE FIRST PART OF THE FCST PERIOD BUT SHOULD REMAIN MVFR THEN REMAIN PRETTY STABLE THROUGH THE REMAINDER OF THE PERIOD. ANTICIPATE SOME PERIODS OF LIGHT FREEZING DRIZZLE AND/OR FLURRIES THROUGH THE FCST TIME AS WELL. GUSTY NNE WINDS THROUGH MUCH OF THE DAY SHOULD RELAX TOWARD EVENING. PREV DISCUSSION... /ISSUED 428 AM CST TUE DEC 30 2014/ SHORT TERM... THE COLD FRONT IS NOW WELL INTO THE PERMIAN BASIN AND BIG COUNTRY WITH MUCH COLDER AIR FILTERING IN BEHIND IT RATHER THAN SURGING AT THIS POINT. WITH A GOOD STRATUS DECK NOW IN PLACE...ALTHOUGH NOT TERRIBLY LOW AT ABOUT 2000 FT AGL...AND LOW LEVEL COLD ADVECTION PERSISTING THROUGH THE DAY...TEMPS WILL HAVE TROUBLE MOVING OFF OF MORNING LOWS. INDEED...WILL LIKELY SEE TEMPS FALL THROUGH ABOUT MID-MORNING BEFORE SOME SLIGHT RECOVERY LATER IN THE DAY. HOWEVER...MAIN FOCUS CONTINUES TO BE ON CHANCE FOR VERY LIGHT PRECIPITATION TODAY AND TONIGHT AND POTENTIAL IMPACTS OF IT WITH TEMPS IN THE TEENS AND 20S. THIS PRECIP EVENT CONTINUES TO LOOK PRIMARILY ISENTROPIC DRIVEN WITH SOME MINOR CONTRIBUTION FROM FRONTOGENETICAL FORCING EARLY ON. ISENTROPIC PROJECTIONS DEPICT LIFT INITIALLY AT THE VERY TOP OF THE COLD AIR...PRIMARILY IN THE WARMER AND DRIER MID LEVELS ABOVE IT. HOWEVER...AS THE COLD AIR DEEPENS THROUGH THE DAY...SOME OF THIS COLD MOISTURE SHOULD BE TAPPED BY THE ISENTROPIC LIFT TO PRODUCE SOME LIGHT PRECIP. BEST WINDOW FOR THIS APPEARS TO BE BETWEEN 3 PM AND MIDNIGHT...AFTER WHICH ISENTROPIC LIFT WEAKENS SIGNIFICANTLY. QUESTION THEN BECOMES PHASE OF THIS PRECIPITATION. PROGGED SOUNDINGS SUPPORT EITHER FREEZING DRIZZLE OR VERY LIGHT SNOW. COLDER LOW LEVELS ACROSS THE NORTH AND WEST MIGHT END UP FAVORING FLURRIES TO A DUSTING OF SNOW WHILE FURTHER SOUTH AND EAST FREEZING DRIZZLE LIKELY TO BE PREDOMINANT. HOW MUCH IS A BIG QUESTION WITH SOUNDINGS SUGGESTING THE MODEL QPF OUTPUT IS OVERDONE. AS FOR POTENTIAL FOR ADVISORY...STILL SOME DETAILS TO WORK OUT SUCH AS FLURRIES VS DRIZZLE AND TIMING OF ONSET OF PRECIP HEAVY AND/OR WIDESPREAD ENOUGH TO BEGIN TO CAUSE TRAVEL ISSUES. SINCE CURRENT EXPECTATION IS THE MORE SIGNIFICANT PART OF THE EVENT IS STILL 8-12 HOURS AWAY AND ANOTHER MODEL RUN AND 12Z UA ANALYSIS SHOULD HELP NARROW DOWN THE DETAILS FURTHER...WILL DEFER ON THE ISSUANCE OF AN ADVISORY ATTM. LONG TERM... AN UA DISTURBANCE ACROSS THE GREAT BASIN IS STILL PROGGED TO PINCH OFF AND DIVE SSE TO ACROSS SRN CALI TOMORROW...AND ACROSS THE DESERT SW ON THURSDAY. AS SUCH...FLOW ALOFT WILL EVOLVE FROM A BROAD CYCLONIC FLOW TO SWRLY FLOW. IF THE ANTICIPATED TRACK OF THE SYSTEM DOES NOT CHANGE...IT WILL MOVE DIRECTLY ACROSS THE SOUTHERN PLAINS FRIDAY NIGHT THEN EXIT TO THE NE BY SATURDAY. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL. TEMPS STRUGGLING TO GET OUT OF THE 20S WILL CHARACTERIZE WEDNESDAY AS THE CAA USHERED IN BY LAST NIGHT/S COLD FRONTAL PASSAGE REMAINS ENTRENCHED. FURTHERMORE...MAY ALSO EXPERIENCE A LINGERING FREEZING DRIZZLE/WINTRY MIX...COURTESY OF MOISTENED ATMOSPHERIC LOW LEVELS AND AN UPSLOPE SFC REGIME. THIS WINTRY MIX MAY BE HARD-PRESSED TO REACH THE GROUND AS IT WILL HAVE TO FALL THROUGH RATHER DRY MID-LEVELS...WHICH IS WHERE THE SLIVER OF UL SUPPORT IS MAXIMIZED. ON THURSDAY DURING THE DAY...A SIMILAR SCENARIO TO WEDNESDAY WILL PLAY OUT...WITH THE DIFFERENCE BEING PROGGED MODEL SOUNDINGS HINTING AT A WARM TONGUE DEVELOPING IN THE MID-LEVELS...THUS SUGGESTING MORE OF A FREEZING RAIN/WINTRY MIX OCCURRENCE. NONETHELESS...THE BEST LIFT IS STILL MAXIMIZED WITHIN THE DRY MID-LEVELS AND HENCE LIGHT PRECIP IS EXPECTED. BY THURSDAY NIGHT HOWEVER...MID-LEVELS ARE SHOWN TO MOISTEN AS THE UA SYSTEM DRAWS NEAR. THE BEST UL SUPPORT IS FINALLY TAPPING INTO ADEQUATE MOISTURE. MID-LEVEL MOISTENING OCCURRING WITHIN THE DENDRITIC ZONE COULD PROMOTE A CHANCE OF SNOW...PARTICULARLY ACROSS THE HIGHER TERRAIN OF THE NWRN ZONES. ELSEWHERE...FREEZING RAIN AND PERHAPS SLEET WILL BE COMMON...WITH THE EXCEPTION OF THE FAR ROLLING PLAINS WHERE A MIX OF A COLD RAIN AND FREEZING RAIN MAY OCCUR...GIVEN TEMPS WILL WARM TO SLIGHTLY ABOVE FREEZING THERE /LOWER 30S ELSEWHERE/. TEMPS WILL WARMUP FURTHER ON FRIDAY...INTO THE MIDDLE TO UPPER 30S ON THE CAPROCK TO UPPER 30S TO LOWER 40S OFF THE CAPROCK...WHICH WILL AFFECT THE PRECIP PHASE. COULD THEREFORE SEE MORE OF A RAIN AND SNOW MIX OR A RAIN AND FREEZING RAIN MIX DEVELOP BY THE EVENING /THE NWRN ZONES WILL BE THE EXCEPTION AS SOUNDING PROFILES SUGGEST LIGHT SNOW THERE/. LATE FRIDAY NIGHT-EARLY SATURDAY MORNING...LARGE SCALE ASCENT WILL BE FLEETING AS THE SYSTEM COMMENCE TO EXIT THE REGION. PERHAPS SOME LINGERING RAIN AND SNOW MIX WILL BE POSSIBLE ACROSS PORTIONS OF THE ROLLING PLAINS EARLY SATURDAY MORNING. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL AND THE RETURN TO SRLY SFC FLOW EARLY NEXT WEEK WILL AID IN PUSHING TEMPS BACK UP TO NEAR 50. NOTE: ALTHOUGH THE WINTRY PRECIP IS EXPECTED TO BE LIGHT THIS WEEK...IT COULD STILL POSE A THREAT FOR HAZARDOUS ROAD CONDITIONS AS A THIN GLAZE OF ICE COULD FORM ACROSS OVERPASSES AND BRIDGES IN PARTICULAR. AS YOU HEAD OUT TO ENJOY THE NEW YEAR FESTIVITIES...CAUTION IS ADVISED. CHECK BACK TO STAY ALERT AND UP TO DATE WITH ANY WEATHER CHANGES. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 20 11 22 17 32 / 30 40 20 10 20 TULIA 22 13 22 19 32 / 30 40 10 10 20 PLAINVIEW 23 14 23 19 32 / 30 40 10 10 20 LEVELLAND 24 16 24 19 32 / 40 50 20 20 20 LUBBOCK 25 16 25 21 32 / 40 50 20 20 20 DENVER CITY 27 18 25 20 33 / 40 50 20 20 30 BROWNFIELD 27 18 25 20 33 / 40 50 20 20 30 CHILDRESS 28 18 25 22 34 / 30 40 10 10 20 SPUR 28 18 25 22 33 / 30 50 20 20 30 ASPERMONT 30 20 27 24 36 / 30 40 20 20 30 && .LUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES: TXZ021>024-027>030-033>036-039>042. && $$ 05/99
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
725 AM CST TUE DEC 30 2014 .UPDATE...ONE FINAL UPDATE TO EXPAND DENSE FOG ADVISORY WEST TO THE RIO GRANDE. && .PREV DISCUSSION... /ISSUED 613 AM CST TUE DEC 30 2014/ AVIATION... LIFR/VLIFR VIS AND CIGS IN AUSTIN AND SAN ANTONIO THIS MORNING WILL CONTINUE UNTIL MID-MORNING WHEN NORTHWESTERLY WINDS PICK UP. THEN MVFR/IFR CIGS THROUGH THE REST OF THE TAF PERIOD. DRT WILL DROP TO IFR SHORTLY AND STAY THAT WAY UNTIL AROUND 18Z. EXPECTING PRECIPITATION WEDNESDAY MORNING AT DRT. HAVE NOT INCLUDED ANY PRECIP IN AUSTIN OR SAN ANTONIO...BUT THERE IS A SLIGHT CHANCE FOR RAIN. IF THERE IS ANY RAIN IT WILL DROP VIS TO MVFR. PREV DISCUSSION... /ISSUED 523 AM CST TUE DEC 30 2014/ UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIAMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLEY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE FOLLOWING COUNTIES: ATASCOSA...BANDERA...BASTROP...BEXAR...BLANCO...BURNET... CALDWELL...COMAL...DIMMIT...EDWARDS...FAYETTE...FRIO...GILLESPIE... GONZALES...GUADALUPE...HAYS...KENDALL...KERR...KINNEY...LEE... LLANO...MAVERICK...MEDINA...REAL...TRAVIS...UVALDE...VAL VERDE... WILLIAMSON...WILSON...ZAVALA. WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. && $$ MESOSCALE/AVIATION...05 SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
613 AM CST TUE DEC 30 2014 .AVIATION... LIFR/VLIFR VIS AND CIGS IN AUSTIN AND SAN ANTONIO THIS MORNING WILL CONTINUE UNTIL MID-MORNING WHEN NORTHWESTERLY WINDS PICK UP. THEN MVFR/IFR CIGS THROUGH THE REST OF THE TAF PERIOD. DRT WILL DROP TO IFR SHORTLY AND STAY THAT WAY UNTIL AROUND 18Z. EXPECTING PRECIPITATION WEDNESDAY MORNING AT DRT. HAVE NOT INCLUDED ANY PRECIP IN AUSTIN OR SAN ANTONIO...BUT THERE IS A SLIGHT CHANCE FOR RAIN. IF THERE IS ANY RAIN IT WILL DROP VIS TO MVFR. && .PREV DISCUSSION... /ISSUED 523 AM CST TUE DEC 30 2014/ UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIAMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLEY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING COUNTIES: ATASCOSA...BANDERA...BASTROP...BEXAR...BLANCO...BURNET... CALDWELL...COMAL...DIMMIT...FAYETTE...FRIO...GILLESPIE...GONZALES... GUADALUPE...HAYS...KENDALL...KERR...LEE...LLANO...MEDINA...TRAVIS... UVALDE...WILLIAMSON...WILSON...ZAVALA. && $$ MESOSCALE/AVIATION...05 SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
544 AM CST TUE DEC 30 2014 .UPDATE... KLBB 88D SHOWING THE EXPANSION OF VERY LIGHT REFLECTIVTY /ZERO TO MINUS 15 DBZ/ BTWN 1000 AND 5000 FT AGL AND LOWERING WITH TIME. THIS SHOULD BE THE PERIOD OF VERY LIGHT FLURRIES AND/OR FREEZING DRIZZLE ASSOCIATED WITH FRONTOGENTICAL FORCING. PER THE HRRR THIS PRECIP SHOULD SHIFT SWD WITH THE FORCING THROUGH THE MORNING. EXPECTATION IS IT SHOULD REMAIN TOO LIGHT CAUSE MUCH IN THE WAY OF DIFFICULTY THIS MORNING...BUT WILL CONTINUE TO MONITOR TRENDS. && .AVIATION... CIGS TO LOWER A BIT MORE DURING THE FIRST PART OF THE FCST PERIOD BUT SHOULD REMAIN MVFR THEN REMAIN PRETTY STABLE THROUGH THE REMAINDER OF THE PERIOD. ANTICIPATE SOME PERIODS OF LIGHT FREEZING DRIZZLE AND/OR FLURRIES THROUGH THE FCST TIME AS WELL. GUSTY NNE WINDS THROUGH MUCH OF THE DAY SHOULD RELAX TOWARD EVENING. && .PREV DISCUSSION... /ISSUED 428 AM CST TUE DEC 30 2014/ SHORT TERM... THE COLD FRONT IS NOW WELL INTO THE PERMIAN BASIN AND BIG COUNTRY WITH MUCH COLDER AIR FILTERING IN BEHIND IT RATHER THAN SURGING AT THIS POINT. WITH A GOOD STRATUS DECK NOW IN PLACE...ALTHOUGH NOT TERRIBLY LOW AT ABOUT 2000 FT AGL...AND LOW LEVEL COLD ADVECTION PERSISTING THROUGH THE DAY...TEMPS WILL HAVE TROUBLE MOVING OFF OF MORNING LOWS. INDEED...WILL LIKELY SEE TEMPS FALL THROUGH ABOUT MID-MORNING BEFORE SOME SLIGHT RECOVERY LATER IN THE DAY. HOWEVER...MAIN FOCUS CONTINUES TO BE ON CHANCE FOR VERY LIGHT PRECIPITATION TODAY AND TONIGHT AND POTENTIAL IMPACTS OF IT WITH TEMPS IN THE TEENS AND 20S. THIS PRECIP EVENT CONTINUES TO LOOK PRIMARILY ISENTROPIC DRIVEN WITH SOME MINOR CONTRIBUTION FROM FRONTOGENETICAL FORCING EARLY ON. ISENTROPIC PROJECTIONS DEPICT LIFT INITIALLY AT THE VERY TOP OF THE COLD AIR...PRIMARILY IN THE WARMER AND DRIER MID LEVELS ABOVE IT. HOWEVER...AS THE COLD AIR DEEPENS THROUGH THE DAY...SOME OF THIS COLD MOISTURE SHOULD BE TAPPED BY THE ISENTROPIC LIFT TO PRODUCE SOME LIGHT PRECIP. BEST WINDOW FOR THIS APPEARS TO BE BETWEEN 3 PM AND MIDNIGHT...AFTER WHICH ISENTROPIC LIFT WEAKENS SIGNIFICANTLY. QUESTION THEN BECOMES PHASE OF THIS PRECIPITATION. PROGGED SOUNDINGS SUPPORT EITHER FREEZING DRIZZLE OR VERY LIGHT SNOW. COLDER LOW LEVELS ACROSS THE NORTH AND WEST MIGHT END UP FAVORING FLURRIES TO A DUSTING OF SNOW WHILE FURTHER SOUTH AND EAST FREEZING DRIZZLE LIKELY TO BE PREDOMINANT. HOW MUCH IS A BIG QUESTION WITH SOUNDINGS SUGGESTING THE MODEL QPF OUTPUT IS OVERDONE. AS FOR POTENTIAL FOR ADVISORY...STILL SOME DETAILS TO WORK OUT SUCH AS FLURRIES VS DRIZZLE AND TIMING OF ONSET OF PRECIP HEAVY AND/OR WIDESPREAD ENOUGH TO BEGIN TO CAUSE TRAVEL ISSUES. SINCE CURRENT EXPECTATION IS THE MORE SIGNIFICANT PART OF THE EVENT IS STILL 8-12 HOURS AWAY AND ANOTHER MODEL RUN AND 12Z UA ANALYSIS SHOULD HELP NARROW DOWN THE DETAILS FURTHER...WILL DEFER ON THE ISSUANCE OF AN ADVISORY ATTM. LONG TERM... AN UA DISTURBANCE ACROSS THE GREAT BASIN IS STILL PROGGED TO PINCH OFF AND DIVE SSE TO ACROSS SRN CALI TOMORROW...AND ACROSS THE DESERT SW ON THURSDAY. AS SUCH...FLOW ALOFT WILL EVOLVE FROM A BROAD CYCLONIC FLOW TO SWRLY FLOW. IF THE ANTICIPATED TRACK OF THE SYSTEM DOES NOT CHANGE...IT WILL MOVE DIRECTLY ACROSS THE SOUTHERN PLAINS FRIDAY NIGHT THEN EXIT TO THE NE BY SATURDAY. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL. TEMPS STRUGGLING TO GET OUT OF THE 20S WILL CHARACTERIZE WEDNESDAY AS THE CAA USHERED IN BY LAST NIGHT/S COLD FRONTAL PASSAGE REMAINS ENTRENCHED. FURTHERMORE...MAY ALSO EXPERIENCE A LINGERING FREEZING DRIZZLE/WINTRY MIX...COURTESY OF MOISTENED ATMOSPHERIC LOW LEVELS AND AN UPSLOPE SFC REGIME. THIS WINTRY MIX MAY BE HARD-PRESSED TO REACH THE GROUND AS IT WILL HAVE TO FALL THROUGH RATHER DRY MID-LEVELS...WHICH IS WHERE THE SLIVER OF UL SUPPORT IS MAXIMIZED. ON THURSDAY DURING THE DAY...A SIMILAR SCENARIO TO WEDNESDAY WILL PLAY OUT...WITH THE DIFFERENCE BEING PROGGED MODEL SOUNDINGS HINTING AT A WARM TONGUE DEVELOPING IN THE MID-LEVELS...THUS SUGGESTING MORE OF A FREEZING RAIN/WINTRY MIX OCCURRENCE. NONETHELESS...THE BEST LIFT IS STILL MAXIMIZED WITHIN THE DRY MID-LEVELS AND HENCE LIGHT PRECIP IS EXPECTED. BY THURSDAY NIGHT HOWEVER...MID-LEVELS ARE SHOWN TO MOISTEN AS THE UA SYSTEM DRAWS NEAR. THE BEST UL SUPPORT IS FINALLY TAPPING INTO ADEQUATE MOISTURE. MID-LEVEL MOISTENING OCCURRING WITHIN THE DENDRITIC ZONE COULD PROMOTE A CHANCE OF SNOW...PARTICULARY ACROSS THE HIGHER TERRAIN OF THE NWRN ZONES. ELSEWHERE...FREEZING RAIN AND PERHAPS SLEET WILL BE COMMON...WITH THE EXCEPTION OF THE FAR ROLLING PLAINS WHERE A MIX OF A COLD RAIN AND FREEZING RAIN MAY OCCUR...GIVEN TEMPS WILL WARM TO SLIGHTLY ABOVE FREEZING THERE /LOWER 30S ELSEWHERE/. TEMPS WILL WARMUP FURTHER ON FRIDAY...INTO THE MIDDLE TO UPPER 30S ON THE CAPROCK TO UPPER 30S TO LOWER 40S OFF THE CAPROCK...WHICH WILL AFFECT THE PRECIP PHASE. COULD THEREFORE SEE MORE OF A RAIN AND SNOW MIX OR A RAIN AND FREEZING RAIN MIX DEVELOP BY THE EVENING /THE NWRN ZONES WILL BE THE EXCEPTION AS SOUNDING PROFILES SUGGEST LIGHT SNOW THERE/. LATE FRIDAY NIGHT-EARLY SATURDAY MORNING...LARGE SCALE ASCENT WILL BE FLEETING AS THE SYSTEM COMMENCE TO EXIT THE REGION. PERHAPS SOME LINGERING RAIN AND SNOW MIX WILL BE POSSIBLE ACROSS PORTIONS OF THE ROLLING PLAINS EARLY SATURDAY MORNING. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL AND THE RETURN TO SRLY SFC FLOW EARLY NEXT WEEK WILL AID IN PUSHING TEMPS BACK UP TO NEAR 50. NOTE: ALTHOUGH THE WINTRY PRECIP IS EXPECTED TO BE LIGHT THIS WEEK...IT COULD STILL POSE A THREAT FOR HAZARDOUS ROAD CONDITIONS AS A THIN GLAZE OF ICE COULD FORM ACROSS OVERPASSES AND BRIDGES IN PARTICULAR. AS YOU HEAD OUT TO ENJOY THE NEW YEAR FESTIVITIES...CAUTION IS ADVISED. CHECK BACK TO STAY ALERT AND UP TO DATE WITH ANY WEATHER CHANGES. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 20 11 22 17 32 / 30 40 20 10 20 TULIA 22 13 22 19 32 / 30 40 10 10 20 PLAINVIEW 23 14 23 19 32 / 30 40 10 10 20 LEVELLAND 24 16 24 19 32 / 40 50 20 20 20 LUBBOCK 25 16 25 20 32 / 40 50 20 20 20 DENVER CITY 27 18 25 20 33 / 40 50 20 20 30 BROWNFIELD 27 18 25 20 33 / 40 50 20 20 30 CHILDRESS 28 18 25 22 34 / 20 40 10 10 20 SPUR 28 18 25 22 33 / 30 50 20 20 30 ASPERMONT 30 20 27 24 36 / 20 40 20 20 30 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07/29/07
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
541 AM CST Tue Dec 30 2014 .DISCUSSION... && .AVIATION... Strong front has moved through the region with a gusty N/NE wind in its wake... gusts should continue through the day. Low clouds have reached most TAF sites and will remain through the day with low MVFR/IFR conditions. Expect a wintry precipitation to develop with freezing rain... freezing drizzle... and sleet along with some fog to reduce vsbys. && .PREV DISCUSSION... /ISSUED 512 AM CST Tue Dec 30 2014/ DISCUSSION...As of 5:00 AM CST Tuesday...Sfc obs indc that the Arctic Front has made it to the Trans Pecos...and continues to surge south. Low clouds have quickly filled in behind the front with low overcast past Wink per sfc obs and satl imagery. Winter weather will be the rule into the New Year. Mild air will override the cold low level airmass. With the lack of jet dynamics isentropic lift will lead to periods of light freezing rain and sleet right thru Wednesday aftn...and possibly into New Years Day. The HRRR model is indc precipitation moving thru the Permian Basin and Southeast New Mexico this morning and moving south of the Pecos River by late morning. Temps will slowly fall through the day with below freezing temps thru New Years Eve. Due to the extended nature of this event and the substantial impacts to holiday travel have upgraded the Winter Storm Watch to a Winter Storm Warning. The warning will continue thru Wed aftn for West Texas and Southeast New Mexico...except for the Presidio Valley where temps could be a little warmer. Strong sfc pressure gradient will lead to high winds thru Guadalupe Pass...the High Wind Watch has been upgraded to a High Wind Warning continuing into Wednesday morning. A combination of gusty winds and very cold temperatures could lead to wind chill values in the single digits in the Plains tonight...with dangerous wind chill values as low as -10F in the Guadalupe Mtns. An upper low over SoCal will move slowly east into Southeast New Mexico Friday night. Light freezing rain and sleet could continue into New Years morning. It is possible that the Winter Storm Warning might need to be extended into New Years morning. Milder air should change the precipitation to rain New Years aftn. However...the ECMWF is showing a deeper cold airmass moving back into the CWA bringing a chance of snow Thursday night...and a chance of a rain/snow mix Friday and Friday night. As the upper low moves east of the CWA...the upcoming weekend will be dry but cool. Southwest flow sfc and aloft will bring dry weather along with a warming trend the beginning of next week. Strobin && .MAF WATCHES/WARNINGS/ADVISORIES... NM...WINTER STORM WARNING until 5 PM MST Wednesday FOR THE FOLLOWING ZONES... Central Lea County...Eddy County Plains... Guadalupe Mountains of Eddy County...Northern Lea County... Southern Lea County. TX...WINTER STORM WARNING until 6 PM CST /5 PM MST/ Wednesday FOR THE FOLLOWING ZONES... Andrews...Big Bend Area...Borden... Crane...Davis/Apache Mountains Area...Dawson...Ector... Gaines...Glasscock...Guadalupe Mountains...Howard... Loving...Marfa Plateau...Martin...Midland...Mitchell... Pecos...Reagan...Reeves County and Upper Trans Pecos... Scurry...Terrell...Upton...Van Horn and Highway 54 Corridor...Ward...Winkler. HIGH WIND WARNING until 8 AM MST Wednesday FOR THE FOLLOWING ZONES... Guadalupe Mountains. && $$ Follow us on Facebook and Twitter at: http://facebook.com/NWSMidland http://twitter.com/NWSMidland Check us out on the internet at: http://weather.gov/midland
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
523 AM CST TUE DEC 30 2014 .UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. && .PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... .FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING COUNTIES: ATASCOSA...BANDERA...BASTROP...BEXAR...BLANCO...BURNET... CALDWELL...COMAL...DIMMIT...FAYETTE...FRIO...GILLESPIE...GONZALES... GUADALUPE...HAYS...KENDALL...KERR...LEE...LLANO...MEDINA...TRAVIS... UVALDE...WILLIAMSON...WILSON...ZAVALA. && $$ MESOSCALE/AVIATION...05 SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
512 AM CST Tue Dec 30 2014 .DISCUSSION...As of 5:00 AM CST Tuesday...Sfc obs indc that the Arctic Front has made it to the Trans Pecos...and continues to surge south. Low clouds have quickly filled in behind the front with low overcast past Wink per sfc obs and satl imagery. Winter weather will be the rule into the New Year. Mild air will override the cold low level airmass. With the lack of jet dynamics isentropic lift will lead to periods of light freezing rain and sleet right thru Wednesday aftn...and possibly into New Years Day. The HRRR model is indc precipitation moving thru the Permian Basin and Southeast New Mexico this morning and moving south of the Pecos River by late morning. Temps will slowly fall through the day with below freezing temps thru New Years Eve. Due to the extended nature of this event and the substantial impacts to holiday travel have upgraded the Winter Storm Watch to a Winter Storm Warning. The warning will continue thru Wed aftn for West Texas and Southeast New Mexico...except for the Presidio Valley where temps could be a little warmer. Strong sfc pressure gradient will lead to high winds thru Guadalupe Pass...the High Wind Watch has been upgraded to a High Wind Warning continuing into Wednesday morning. A combination of gusty winds and very cold temperatures could lead to wind chill values in the single digits in the Plains tonight...with dangerous wind chill values as low as -10F in the Guadalupe Mtns. An upper low over SoCal will move slowly east into Southeast New Mexico Friday night. Light freezing rain and sleet could continue into New Years morning. It is possible that the Winter Storm Warning might need to be extended into New Years morning. Milder air should change the precipitation to rain New Years aftn. However...the ECMWF is showing a deeper cold airmass moving back into the CWA bringing a chance of snow Thursday night...and a chance of a rain/snow mix Friday and Friday night. As the upper low moves east of the CWA...the upcoming weekend will be dry but cool. Southwest flow sfc and aloft will bring dry weather along with a warming trend the beginning of next week. Strobin && .PRELIMINARY POINT TEMPS/POPS... ANDREWS TX 29 20 24 22 / 60 60 50 30 BIG SPRING TX 31 20 24 24 / 60 60 50 30 CARLSBAD NM 31 23 25 23 / 40 60 50 30 DRYDEN TX 41 32 32 29 / 50 60 50 20 FORT STOCKTON TX 32 20 29 25 / 50 60 60 20 GUADALUPE PASS TX 26 14 21 19 / 40 50 60 20 HOBBS NM 29 21 24 21 / 60 60 50 30 MARFA TX 37 19 31 22 / 30 40 50 20 MIDLAND INTL AIRPORT TX 30 19 25 23 / 60 60 50 30 ODESSA TX 29 20 25 23 / 60 60 50 30 WINK TX 32 28 29 26 / 40 60 50 20 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...WINTER STORM WARNING until 5 PM MST Wednesday FOR THE FOLLOWING ZONES... Central Lea County...Eddy County Plains... Guadalupe Mountains of Eddy County...Northern Lea County... Southern Lea County. TX...WINTER STORM WARNING until 6 PM CST /5 PM MST/ Wednesday FOR THE FOLLOWING ZONES... Andrews...Big Bend Area...Borden... Crane...Davis/Apache Mountains Area...Dawson...Ector... Gaines...Glasscock...Guadalupe Mountains...Howard... Loving...Marfa Plateau...Martin...Midland...Mitchell... Pecos...Reagan...Reeves County and Upper Trans Pecos... Scurry...Terrell...Upton...Van Horn and Highway 54 Corridor...Ward...Winkler. HIGH WIND WARNING until 8 AM MST Wednesday FOR THE FOLLOWING ZONES... Guadalupe Mountains. && $$ 72/33 Follow us on Facebook and Twitter at: http://facebook.com/NWSMidland http://twitter.com/NWSMidland Check us out on the internet at: http://weather.gov/midland
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS MIAMI FL
430 PM EST TUE DEC 30 2014 ...VERY WARM, HUMID PATTERN TO CONTINUE INTO THE NEW YEAR... .UPDATE...SEA BREEZES HAVE DEVELOPED ALONG BOTH THE GULF AND ATLANTIC COASTS THIS AFTERNOON...CLEARLY SEEN IN VISIBLE SATELLITE IMAGERY. PRETTY RARE FOR WINTERTIME! ENOUGH LOW LEVEL MOISTURE IS PRESENT TO HAVE CU FORMING ALONG THE SEA BREEZE FRONTS, BUT NOT QUITE ENOUGH TO GET SHOWERS GOING. HRRR IS OVERDOING QPF AS RADAR CONTINUES TO SHOW NO SHOWER ACTIVITY (ECHOES SOUTH OF LAKE OKEECHOBEE ARE REFLECTIVE OF SUGARCANE BURNING). AS DAYTIME HEATING IS LOSS, IT LOOKS LIKE CONDITIONS WILL REMAIN DRY THROUGH TONIGHT...BUT AS THE WEAKENING COLD FRONT OVER CENTRAL FLORIDA SAGS SOUTHWARD, SOME CONVERGENCE ALONG THE PALM BEACH COAST COULD ALLOW FOR A FEW SHOWERS TO DEVELOP THERE LATER TONIGHT...SO KEPT SHOWER MENTION IN THERE ONLY. SOUTH FL CONTINUES WITH ABOVE NORMAL TEMPS ALONG WITH HUMIDITY...AND THIS WILL CONTINUE INTO THE WEEKEND AND EARLY NEXT WEEK! A RECORD HIGH OF 83F WAS TIED AT MIAMI TODAY. THE HOTTEST READINGS WERE FROM OPA LOCKA (KOPF) TO PEMBROKE PINES (KHWO) TO WEST PALM BEACH (KPBI) WHERE HIGHS OFFICIALLY REACHED 85F, THE WARMEST IN THE COUNTRY (FOR MAJOR REPORTING STATIONS/SOME UPPER 80S WERE REGISTERED BY MESONETS OVER PORTIONS OF INTERIOR SOUTH FL THIS AFTERNOON). THE WARM PATTERN WILL CONTINUE WITH POSSIBLY BUILDING HEAT BY THIS WEEKEND. ECMWF INDICATES MAX TEMPS INTO THE MID-UPPER 80S EAST COAST METRO WITH DEWPOINTS INTO THE LOWER 70S EQUATING TO HEAT INDICES INTO THE LOWER 90S! GFS AND MODEL BLENDS OFFER SLIGHTLY COOLER READINGS...AND THAT`S WHAT OUR CURRENT FORECAST REFLECTS. HOWEVER, WE VERY WELL MAY NEED TO INCREASE OUR HIGHS PROJECTED FOR THIS UPCOMING WEEKEND. A POSSIBLE "MINI-HEAT WAVE" TO START 2015. /GREGORIA && .PREV DISCUSSION... /ISSUED 247 PM EST TUE DEC 30 2014/ SHORT TERM (TONIGHT-NEW YEARS` DAY)... A MOSTLY ZONAL UPPER FLOW PATTERN WILL CONTINUE ACROSS SOUTH FLORIDA THROUGH NEW YEARS` DAY AS A STRONG RIDGE REMAINS ACROSS CUBA AND THE BAHAMA ISLANDS. A WEAK COLD FRONT CURRENTLY IN NORTH CENTRAL FLORIDA WILL OOZE INTO SOUTH FLORIDA TONIGHT AND WEDNESDAY BEFORE STALLING AND RAPIDLY BECOME DIFFUSE. THERE WILL BE SOME CLOUDS WITH THE FRONTAL BOUNDARY BUT VERY LITTLE IN THE WAY OF RAINFALL AS DEEP LAYER MOISTURE WILL BE LACKING. THERE IS SOME POTENTIAL FOR FOG AGAIN OVER THE INTERIOR AHEAD OF THE FRONT. HOWEVER, EXTENSIVE CLOUD COVER WILL LIKELY HAMPER FOG DEVELOPMENT AND WILL LEAVE OUT OF FORECAST AT THIS TIME WITH THE SREF ONLY SHOWING A 30-40% CHANCE OF VISIBILITY LOWERING LESS THAN THREE MILES. DUE TO THE LACK OF PUSH WITH THIS FRONT, THE STRONG SUBSIDENCE CAP CURRENTLY OVER SOUTH FLORIDA WILL BE SLOW TO ERODE WITH FORECAST SOUNDINGS ONLY INDICATING SOME INSTABILITY BY LATE WEDNESDAY AND EVEN THEN A PWAT OF ONLY AROUND 1.3". LONG TERM (FRIDAY-TUESDAY)... NOT MANY CHANGES SEEN TO THE UPPER FLOW PATTERN IN THE EXTENDED PERIOD AS THE SUBTROPICAL RIDGE REMAINS FIRMLY ENTRENCHED IN ITS POSITION ACROSS THE BAHAMA ISLAND CHAIN. AT THE SURFACE, WHAT IS LEFT OF THE FRONTAL BOUNDARY WILL LIFT BACK TO THE NORTH WEDNESDAY NIGHT OR THURSDAY. THIS IS IN RESPONSE TO A POWERFUL TROUGH CURRENTLY DEEPENING INTO THE FOUR CORNERS AREA THAT WILL MOVE INTO THE CENTRAL/SOUTHERN PLAINS ON FRIDAY NIGHT AND SATURDAY THEN INTO THE GREAT LAKES AND NEW ENGLAND THIS WEEKEND. A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL THEN MOVE INTO NORTH FLORIDA ON SUNDAY WHERE IT WILL STALL INTO EARLY NEXT WEEK. SO THESE TWO PARAGRAPHS SPELL OUT A WARM AND GENERALLY DRY PATTERN FOR SOUTH FLORIDA TO END THIS YEAR AND THE BEGINNING OF THE NEW YEAR. MARINE... GOOD BOATING CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD WITH A LIGHT WIND EXPECTED AND SEAS 4 FEET OR LESS. THE PRESSURE GRADIENT WILL REMAIN WEAK AS THE COLD FRONT BECOMES DIFFUSE AND THEN SLOWLY LIFTS TO THE NORTH TOWARDS THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 69 79 68 78 / 20 40 20 20 FORT LAUDERDALE 70 80 69 79 / 10 30 20 20 MIAMI 70 81 69 80 / 10 20 10 20 NAPLES 66 79 65 79 / 10 20 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
300 PM EST TUE DEC 30 2014 .UPDATE (REST OF TODAY THROUGH WEDNESDAY)... 20Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW MUCH OF THE NATION UNDER A BROAD LONGWAVE TROUGH. THE MOST ENERGETIC FEATURE WITHIN THIS TROUGH IS A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE INTERMOUNTAIN WEST WHICH IS PROGGED BY ALL THE NUMERICAL GUIDANCE TO BECOME A LARGE CUTOFF LOW OVER THE SOUTHWESTERN STATES BEFORE EJECTING EASTWARD ACROSS THE SOUTHERN/CENTRAL PLAINS LATER IN THE WEEK. OUR FORECAST AREA RESIDES WITHIN A ZONE OF DEEP LAYER SOUTHWEST FLOW BETWEEN THE LONGWAVE TROUGH AND AND WEST-EAST ORIENTED RIDGE ACROSS THE NORTHWEST CARIBBEAN. A PLUME OF SOUTHERN STREAM MOISTURE IS STILL IN WV IMAGERY RIDGING THIS FLOW OVER THE EASTERN GULF OF MEXICO AND FL PENINSULA. AT THE SURFACE...A WEAK COLD FRONT IS NOW ALIGNED ACROSS THE CENTRAL FLORIDA PENINSULA AND IS MAKING VERY SLOW PROGRESS SOUTHWARD. REGIONAL RADARS SHOW A SWATH OF LIGHT SHOWERS AND AREAS OF DRIZZLE ALONG AND NOW BEHIND THIS BOUNDARY. THIS TRANSITION FROM A KATAFRONT TO AN ANAFRONT CONFIGURATION HAS HELPED KEEP THE RAIN ACROSS MANY OF THE SAME PLACES SO FAR TODAY...EVEN THROUGH THE FRONT ITSELF HAS MADE STEADY PROGRESS TO THE SOUTH SINCE EARLY THIS MORNING. && .SHORT TERM (REST OF TODAY THROUGH WEDNESDAY)... REST OF TODAY...THE FRONT STILL LOOKS TO SLOWLY SETTLE SOUTH TO NEAR PUNTA GORDA AROUND SUNSET. THE ORGANIZATION AND COVERAGE OF SHOWERS HAS DIMINISHED SOMEWHAT IN THE PAST COUPLE OF HOURS AS THE WEAK SHORTWAVE TO OUR NORTH IS NOW PASSING BY. HOWEVER...THE LOW LEVEL BOUNDARY FOCUS WILL STILL KEEP THE CHANCE FOR MORE SCT SHOWERS IN THE FORECAST...GENERALLY SOUTH OF HERNANDO COUNTY AND TO THE NORTH OF THE SARASOTA TO PUNTA GORDA REGION. ALSO WITH THE FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...THE ACTUALLY BOUNDARY PASSAGE WILL NOT NECESSARILY END THE CHANCE FOR RAIN. MANY OF THE GUIDANCE MEMBERS WERE INDICATING THE BOUNDARY TAKING ON AN INCREASINGLY ANAFRONT CONFIGURATION WHERE BETTER CHANCES FOR THE CLOUDS AND SHOWERS ARE ACTUALLY ALONG AND BEHIND THE BOUNDARY. THIS APPEARS TO BE TAKING SHAPE THIS AFTERNOON AS THE FRONT IS NOW DOWN SOUTH OF THE TAMPA BAY/POLK COUNTY REGION...AND YET MUCH OF THE LIGHT SHOWERS/DRIZZLE ARE STILL REMAINS ALONG THE GENERAL I-4 CORRIDOR. FOR OUR FAR NORTHERN ZONES...THE RAIN IS OVER AND DRIER AIR WILL CONTINUE TO SETTLE BEHIND THE FRONT THROUGH EARLY THIS EVENING. FOR OUR FAR SOUTHERN ZONES...WELL...THE WITH THE FRONT BECOMING MORE ANAFRONT WITH TIME...THE SHOWERS SOUTHWARD MARCH AS SLOWED TO A CRAWL. EVENTUALLY A FEW SHOWERS/PATCHES OF DRIZZLE SHOULD MAKE IT DOWN TO SARASOTA/PUNTA GORDA AND FORT MYERS...BUT IS LOOKING MORE LIKELY TO BE TONIGHT THAN DURING THE ACTUAL DAYLIGHT HOURS TODAY. TONIGHT AND WEDNESDAY...THE FRONT STALLS AND BEGINS TO WASH OUT OVER THE SOUTHERN PENINSULA. WILL KEEP LOW POPS FOR LIGHT SHOWERS/DRIZZLE FOR THE FIRST HALF OF THE OVERNIGHT...MAINLY TO THE SOUTH OF THE TAMPA BAY REGION AND THEN LOOKS AS THROUGH MOST OF THE ACTIVITY SHOULD FADE. THERE IS GOING TO BE QUITE A BIT OF LOW LEVEL MOISTURE STILL IN PLACE OVERNIGHT...AND THE SREF AND STATISTICAL GUIDANCE ARE SHOWING A LOT OF LOWER CLOUDS DEVELOPING. SO EVEN PLACE THAT DO NOT CLOUD OVER DURING THE DAY FROM THE FRONT ITSELF...SHOULD BEGIN TO BECOME OVERCAST OVERNIGHT. THESE CLOUDS WILL LIKELY BE WITH US FOR A GOOD PORTION OF THE DAY ON WEDNESDAY (ESPECIALLY THE FIRST HALF)...AND HENCE WILL NOT HAVE ALL THAT MUCH SUN IN THE FORECAST FOR WEDNESDAY. THE GUIDANCE MEMBERS ARE INDICATING THE DEVELOPMENT OF AN INVERTED TROUGH OVER THE GULF STREAM OFF THE FL EAST COAST DURING LATER TONIGHT AND EARLY WEDNESDAY THAT THEN MIGRATES WESTWARD A BIT DURING THE DAY. THIS FOCUS ALONG WITH SOME SPEED CONVERGENCE ALONG THE COAST LOOKS TO BE ENOUGH FOR SHOWERS TO BEGIN MIGRATING ONSHORE. NOT IMPOSSIBLE THAT A FEW OF THESE SHOWERS OR SPRINKLES COULD SURVIVE THE TREK ACROSS THE PENINSULA TO REACH SOME OF OUR EASTERN AND SOUTHERN ZONES. GOING TO KEEP THE POPS AT OR BELOW 20% FOR NOW...AND WILL MENTION A FEW SPRINKLES IN THE FORECAST WEDNESDAY FOR THE SOUTHERN HALF OF THE FORECAST AREA. THOSE SPRINKLES SHOULD BE GONE BY TOMORROW EVENING...AND AS IT LOOKS NOW...ALTHOUGH A LOT OF CLOUDS AROUND...THE WEATHER FOR AFTER DARK ON NEW YEARS EVE LOOKS DRY WITH SEASONABLE TEMPERATURES. && .LONG TERM (THURSDAY THROUGH NEXT TUESDAY)... ZONAL FLOW ALOFT AND WEAK RIDGING WILL BE IN PLACE TO START THE PERIOD WITH A REMNANT BOUNDARY DRAPED ACROSS SOUTH FL. THE BOUNDARY WILL LIFT NORTH OVER THE AREA INTO FRIDAY AS A TROUGH DEVELOPS OVER THE GULF STREAM JUST OFF THE FL EAST COAST AND A WEAK LOW DEEPENS OFF OF THE TEXAS COAST IN THE GULF OF MEXICO. THIS WILL ALLOW FOR A SLIGHT CHANCE OF RAIN WEDNESDAY NIGHT AND THURSDAY. FLOW ALOFT WILL BECOME SW FOR THE WEEKEND AS WEAK RIDGING BUILDS OVER THE STATE FROM THE ATLANTIC AND THE LOW OFF OF TEXAS LIFTS NE AND DRAGS A COLD FRONT INTO THE REGION BY SUNDAY. THE FRONT WILL SETTLE INTO THE AREA SUNDAY AFTERNOON AND THEN STALL ACROSS THE NORTHERN HALF OF THE PENINSULA FOR EARLY NEXT WEEK. THIS WILL ALLOW FOR A FEW SHOWERS MAINLY ACROSS THE NATURE COAST SATURDAY THROUGH SUNDAY...AND INLAND ACROSS THE AREA MONDAY. TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE WEEKEND AND FALL A COUPLE OF DEGREES TO CLOSER TO NORMAL FOR EARLY NEXT WEEK. && .AVIATION... MVFR TO OCCASIONAL IFR CONDITIONS THIS AFTERNOON FROM KSRQ/KPIE/KTPA AND KLAL. SOUTH OF THE FRONTAL BAND FROM KPGD TO KRSW WILL CONTINUE TO SEE PREVAILING VFR CONDITIONS INTO THE EVENING HOURS. GOOD AGREEMENT AMONG THE DETERMINISTIC AND STATISTICAL GUIDANCE THAT WE WILL SEE AN EXPANSION OF THE LOWER CLOUDS DURING THE SECOND HALF OF THE NIGHT INTO WEDNESDAY MORNING. SO ALTHOUGH EVEN THE NORTHERN TERMINALS MAY SEE A BRIEF WINDOW OF IMPROVEMENT THIS EVENING...GOING WITH PREVAILING MVFR CIGS FOR ALL TERMINALS AFTER 06Z. IF THE MAV IS CORRECT THAN PERIODS OF IFR CIGS ARE POSSIBLE. BEST CHANCES TO SEE ANY FOG/VIS RESTRICTIONS WILL BE DOWN TOWARD KPGD AND KRSW. EXPECT MVFR CATEGORY CIGS TO HOLD THROUGH MUCH OF THE MORNING AT MANY SPOTS...IF NOT UNTIL THE END OF THE TAF PERIOD. && .MARINE... MARINE FORECAST AREA REMAINS DIVIDED WITH IMPACTS ASSOCIATED WITH A QUASI-STATIONARY FRONTAL SYSTEM DRAPED OVER THE WATERS FROM OFF HERNANDO BEACH SOUTHWARD TO OFF THE COAST FROM VENICE. MAIN AREA OF SHOWERS EXTENDS OFF THE COAST OF HOLIDAY AND OUT 100 NM INTO THE EASTERN GULF OF MEXICO. CONDITIONS EARLY THIS AFTERNOON /2PM/ REPORTS SEAS AROUND 6 FEET WITH A PERIOD OF 5 SECONDS AT BUOY036 112 MILES W-NW OF TAMPA WHILE BUOY03 REPORTS SEAS OF 2 FEET AND A PERIOD OF 8 SECONDS IN THE CALMER AIRMASS 208 MILES WEST OF NAPLES. NO FLAGS EXPECTED THROUGH THE PERIOD AND SHOWER ACTIVITY WILL GRADUALLY DIMINISH TONIGHT. && .FIRE WEATHER... NO SIGNIFICANT FIRE WEATHER CONCERNS EXPECTED THE NEXT SEVERAL DAYS. WEAK COLD FRONT WILL EXIT SOUTH OF THE AREA THIS EVENING ALLOWING SOMEWHAT DRIER AIR TO ARRIVE FROM THE NORTH FOR WEDNESDAY AND THURSDAY. THEREAFTER...INCREASING TEMPERATURES AND LOW LEVEL MOISTURE IS EXPECTED FOR THE END OF THE WEEK. FOG POTENTIAL... PATCHY FOG IS EXPECTED TO DEVELOP OVERNIGHT...MAINLY TO THE SOUTH OF THE I-4 CORRIDOR WITH THE BEST CHANCES FOR ANY SIGNIFICANT FOG OCCURRING FROM AROUND PUNTA GORDA AND SOUTHWARD. && .PRELIMINARY POINT TEMPS/POPS... TPA 61 75 60 76 / 40 10 10 10 FMY 65 79 64 80 / 30 20 10 20 GIF 61 76 58 76 / 40 10 10 10 SRQ 63 77 61 77 / 40 10 10 10 BKV 58 74 54 74 / 20 10 20 10 SPG 63 75 61 74 / 40 10 10 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/AVIATION/FIRE WX...MROCZKA LONG TERM...HUBBARD MARINE...LAMARRE
AREA FORECAST DISCUSSION
NWS POCATELLO ID
155 PM MST TUE DEC 30 2014 .SHORT TERM...TONIGHT THROUGH FRIDAY. AN AMPLIFIED RIDGE OF HIGH PRESSURE WILL PREVAIL ALONG THE PAC COAST THROUGH THURSDAY MAINTAINING THE COLD ARCTIC NNE FLOW ACROSS THE REGION. THUS WIND CHILL WARNINGS WILL CONTINUE ACROSS THE UPPER SNAKE RIVER PLAIN/HIGHLANDS AND ADJOINING TRIBUTARIES WHERE ELEVATED WIND SPEEDS WILL CREATE DANGEROUSLY COLD WIND CHILL VALUES. VALLEY FOG AND LOW CLOUDS OVER BOISE/MOUNTAIN HOME MAY CONTINUE TO BACK UP THE VALLEY INTO THE LOWER SNAKE RIVER PLAIN/ERN MAGIC VALLEY OVERNIGHT WHICH MAY ALSO HELP TO MODERATE THE FRIGIDLY COLD TEMPS IN THAT AREA. BY FRIDAY...THE RIDGE WEAKENS AS A PAC STORM BREAKS INTO WRN CANADA ENCOURAGING DAYTIME HIGH TEMPERATURES TO WARM TO NEAR NORMAL LEVELS. HUSTON .LONG TERM...FRIDAY NIGHT THROUGH NEXT TUESDAY NIGHT. TWO SHORTWAVES EXPECTED TO MOVE THROUGH CENTRAL AND EASTERN IDAHO...ONE ON THE VERY FIRST PERIOD (FRI NIGHT)...AND A SECOND FROM LATE SUN THROUGH MON. THEY BOTH AFFECT MAINLY THE NORTHERN HALF OF THE FORECAST AREA...WITH NEARLY ZERO PRECIPITATION EXPECTED IN THE SOUTH CENTRAL HIGHLANDS AND PARTS OF THE EASTERN MAGIC VALLEY. TERRAIN EFFECTS ARE STRONG...WITH A LIGHT SNOW EVENT EXPECTED IN THE SNAKE RIVER PLAIN...BUT MODERATE RIGHT NOW FOR THE MOUNTAINS. BY THE END OF THE PERIOD...AN UPPER LEVEL RIDGE BEGINS TO BUILD INTO SOUTHERN IDAHO. THIS PUSHES THE STORM TRACK FARTHER NORTH AND AWAY FROM THE GEM STATE. THERE IS A SHORTWAVE THAT ARRIVES IN THE FINAL 24 HOURS OF THE FORECAST THAT MAY BRUSH THE IDAHO-MONTANA BORDER REGION...BUT ITS EFFECTS SHOULD BE SLIGHT. THE UPPER LEVEL LONG WAVE PATTERN IS ALSO SHIFTING IN THIS WAY...REINFORCING THE LIKELIHOOD OF THE RIDGE BUILDING INTO IDAHO FOR A DRIER END TO THIS PERIOD. MESSICK && .AVIATION...ARCTIC AIR HAS MOVED IN AND STABILIZED...SO NOT LOOKING FOR THE GUSTY WIND AGAIN TONIGHT...ALTHOUGH AMBIENT TEMPERATURES WILL ACTUALLY BE COLDER. THE MAIN FORECAST PROBLEM THOUGH IS WHETHER OR NOT THE STRATUS EXPECTED BY MOS GUIDANCE WILL APPEAR OR NOT. TIME-HEIGHT CROSS SECTIONS DO NOT HAVE ANY BOUNDARY LAYER HUMIDITY THAT EXCEEDS 90 PERCENT EXCEPT FOR KBYI. THIS MORNING THERE WAS A LARGE STRATUS AREA IN THE TREASURE VALLEY AND WESTERN MAGIC VALLEY...SO IT IS A CONCERN THAT THE STRATUS COULD SPREAD FROM THERE INTO THE EASTERN MAGIC VALLEY AND KBYI. THE HRRR AND NAM NOW INDICATE THAT THE EASTERLY WIND WILL WEAKEN AT KBYI AND GO LIGHT AND VARIABLE AFTER 31/07Z OR SO...SO THIS WOULD LIKELY BE THE TIME OF ARRIVAL OF ANY STRATUS. HAVE UPDATED TO PUT THIS INTO THE KBYI TAF. THE OTHER TWO LOW ELEVATION AIRPORTS COULD STILL EXPERIENCE SOME STRATUS...BUT BOUNDARY LAYER HUMIDITY IS NOT AS GOOD...SO HAVE PUT IN A FEW CLOUDS BELOW 1000 FT. KSUN WAS EXPECTED TO BE IN THE CLEAR...BUT AN AREA OF STRATUS HAS MOVED THROUGH THE SAWTOOTHS AND IS LYING JUST TO THE SOUTH OF THE KSUN AIRDROME. ANY RETURN TO A SOUTHERLY COMPONENT TO THE WIND AT KSUN COULD ADVECT THE STRATUS INTO THE AIRPORT AREA. ONCE WIND THERE SWITCHES BACK TO NORTHWEST DURING THE EARLY EVENING...THIS SHOULD END THE THREAT TO THE CIG AT KSUN. MESSICK && .PIH WATCHES/WARNINGS/ADVISORIES... WIND CHILL WARNING CONTINUES UNTIL NOON WEDNESDAY IDZ019. WIND CHILL WARNING FROM 8 PM MST THIS EVENING UNTIL NOON WEDNESDAY IDZ020-021-032. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1243 PM EST TUE DEC 30 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 304 AM EST TUE DEC 30 2014 IN THE NEAR TERM PERIOD...THE FOCUS WILL BE ON THE COOL DOWN AS ARCTIC HIGH PRESSURE STRENGTHENS OVER WESTERN CANADA. MUCH COLDER AIR WILL SPILL INTO PORTIONS OF THE CONTINENTAL U.S. AS A RESULT. HOWEVER...NO PRECIPITATION IS EXPECTED UNTIL THE EXTENDED PERIOD WHEN A CUT OFF LOW OVER THE DESERT SOUTHWEST MAKES ITS PROGRESSION ACROSS THE PLAINS...AND INTO CENTRAL INDIANA. TIMING AND TRACKING INCONSISTENCIES ARE MAKING IT DIFFICULT TO PINPOINT PRECIP TYPE AT THIS TIME...BUT EARLY INDICATIONS ARE SHOWING MIXED PRECIPITATION FOR MOST OF FRIDAY AND SATURDAY. PRECIP WILL END FROM WEST TO EAST ON SUNDAY...AND THE REMAINDER OF THE EXTENDED FORECAST WILL BE DRY AS FLOW ALOFT BECOMES MORE ZONAL ON MONDAY. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 950 AM EST TUE DEC 30 2014 FLURRIES WILL BE REMOVED FROM THE NORTHWEST. EVEN IN CLEAR AIR MODE THE RADARS UPSTREAM DONT SHOW ANYTHING AND THE HRRR DOESNT INTRODUCE ANYTHING. OTHER ELEMENTS OF THE EARLIER FORECAST ARE WORKING WELL BASED ON THE LATEST OBSERVATIONS.&& .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 410 AM EST MON DEC 30 2014 THERE IS BETTER AGREEMENT BETWEEN THE MODELS AS THEY ALL BRING PRECIPITATION NORTH ACROSS OUR ENTIRE REGION FRIDAY NIGHT THROUGH SATURDAY. PREVIOUSLY THE EURO ONLY BROUGHT IT INTO OUR SOUTHERN AREAS...WHILE MOST OTHER MODELS BROUGHT IT FARTHER NORTH. WITH THE EXCEPTION OF THE NAM ALL MODELS HAVE TRENDED A LITTLE SLOWER IN NOT BEGINNING PRECIPITATION UNTIL FRIDAY NIGHT. WILL GO ALONG WITH THIS SCENARIO AND KEEP ALL BUT THE FAR SOUTH DRY UNTIL FRIDAY NIGHT. PRECIPITATION WILL BE THE MAIN ISSUE FRIDAY NIGHT AND SATURDAY AS MODELS PULL WARMER NORTH INTO OUR REGION. BUFKIT SOUNDINGS INDICATE LOW CHANCES OF SNOW ACROSS OUR NORTH AND FREEZING PRECIPITATION SOUTH EARLY FRIDAY NIGHT AND WITH THICKNESS AND TEMPERATURES RISING SLOWLY OVERNIGHT WHICH SHOULD ALLOW CHANCES OF FREEZING RAIN TO SPREAD NORTH BY SATURDAY MORNING AND THEN PRECIPITATION BEING MOSTLY RAIN SATURDAY AFTERNOON. ALL MODELS INDICATE QUITE A BIT OF PRECIPITATION AROUND SATURDAY AND WENT WITH HPC PROGS WHICH INDICATED LIKELY POPS CENTRAL AND SOUTH SATURDAY. AFTER LOW PRESSURE GOES BY...MODELS INDICATE A CHANGEOVER BACK TO LIGHT SNOW OR FLURRIES SATURDAY NIGHT WITH RETURN OF COLDER AIR. WILL ALSO MENTION SLIGHT CHANCE OF SNOW SHOWERS WITH MIXED PRECIP FAR SOUTHEAST SUNDAY MORNING AND THEN DRY AFTER THAT AS COLD HIGH PRESSURE BUILDS BACK IN. MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING AS TEMPERATURES WILL BE NON-DIURNAL. OTHERWISE...MADE ONLY MINOR TWEAKS TO A MOS BLEND ON TEMPERATURES MOST OTHER PERIODS. && .AVIATION /DISCUSSION FOR THE 301800Z TAF ISSUANCE/... ISSUED AT 1233 PM EST TUE DEC 30 2014 MAINLY VFR CONDITIONS EXPECTED THROUGH MOST OF THE TAF PERIOD. THE ONE CAVEAT TO THAT IS THE BAND OF SCT/BKN MVFR CEILINGS EXISTING WITHIN THE 2 OR 3 COUNTY WIDE BAND OF CLOUDS CURRENTLY EXTENDING DOWN FROM NORTH CENTRAL INDIANA THROUGH WEST CENTRAL INDIANA. UNDERNEATH SOME OF THE MORE CONCENTRATED CLOUD SHIELD...BKN TO OVC MVFR CEILINGS ARE PERSISTING. EXPECT THOSE MVFR CEILINGS TO MOVE OUT OF LAF BY 30/20Z AND OUT OF HUF AROUND 30/21Z. DO CURRENTLY EXPECT TO SEE THOSE MVFR CEILINGS MAKE IT INTO IND AROUND 30/18Z AND INTO BMG BY 30/19Z AS CU FIELD IS THICKENING ACROSS WEST- CENTRAL AND CENTRAL PORTIONS OF CENTRAL INDIANA. EXPECT THE MVFR CEILINGS TO SCATTER OR MOVE FROM IND/BMG BY 30/22-23Z. ALONG WITH THE INCREASE IN CLOUDS...A GRADUAL BACKING OF WINDS TO THE NORTHWEST IS EXPECTED AS WELL. WOULD NOT BE SURPRISED TO SEE AN OB OR TWO FROM LAF WITH -SN SENSING FLURRIES WITHIN THE NEXT FEW HOURS AS WELL. OTHERWISE...EXPECT VFR CONDITIONS WITH FEW/SCT CU AND A SCATTERED MID-LEVEL DECK. MODEL SOUNDINGS CONTINUE TO INDICATE CLEARING OCCURRING TONIGHT AS ARCTIC HIGH PRESSURE BUILDS INTO THE GREAT PLAINS STATES. NORTH WINDS AROUND 10 KNOTS WILL BECOME NORTHWEST THIS AFTERNOON AND WEST AROUND 5 TO 7 KNOTS LATE TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...JK SHORT TERM...TDUD LONG TERM...JH AVIATION...MRD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1212 PM EST TUE DEC 30 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 304 AM EST TUE DEC 30 2014 IN THE NEAR TERM PERIOD...THE FOCUS WILL BE ON THE COOL DOWN AS ARCTIC HIGH PRESSURE STRENGTHENS OVER WESTERN CANADA. MUCH COLDER AIR WILL SPILL INTO PORTIONS OF THE CONTINENTAL U.S. AS A RESULT. HOWEVER...NO PRECIPITATION IS EXPECTED UNTIL THE EXTENDED PERIOD WHEN A CUT OFF LOW OVER THE DESERT SOUTHWEST MAKES ITS PROGRESSION ACROSS THE PLAINS...AND INTO CENTRAL INDIANA. TIMING AND TRACKING INCONSISTENCIES ARE MAKING IT DIFFICULT TO PINPOINT PRECIP TYPE AT THIS TIME...BUT EARLY INDICATIONS ARE SHOWING MIXED PRECIPITATION FOR MOST OF FRIDAY AND SATURDAY. PRECIP WILL END FROM WEST TO EAST ON SUNDAY...AND THE REMAINDER OF THE EXTENDED FORECAST WILL BE DRY AS FLOW ALOFT BECOMES MORE ZONAL ON MONDAY. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 950 AM EST TUE DEC 30 2014 FLURRIES WILL BE REMOVED FROM THE NORTHWEST. EVEN IN CLEAR AIR MODE THE RADARS UPSTREAM DONT SHOW ANYTHING AND THE HRRR DOESNT INTRODUCE ANYTHING. OTHER ELEMENTS OF THE EARLIER FORECAST ARE WORKING WELL BASED ON THE LATEST OBSERVATIONS.&& .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 410 AM EST MON DEC 30 2014 THERE IS BETTER AGREEMENT BETWEEN THE MODELS AS THEY ALL BRING PRECIPITATION NORTH ACROSS OUR ENTIRE REGION FRIDAY NIGHT THROUGH SATURDAY. PREVIOUSLY THE EURO ONLY BROUGHT IT INTO OUR SOUTHERN AREAS...WHILE MOST OTHER MODELS BROUGHT IT FARTHER NORTH. WITH THE EXCEPTION OF THE NAM ALL MODELS HAVE TRENDED A LITTLE SLOWER IN NOT BEGINNING PRECIPITATION UNTIL FRIDAY NIGHT. WILL GO ALONG WITH THIS SCENARIO AND KEEP ALL BUT THE FAR SOUTH DRY UNTIL FRIDAY NIGHT. PRECIPITATION WILL BE THE MAIN ISSUE FRIDAY NIGHT AND SATURDAY AS MODELS PULL WARMER NORTH INTO OUR REGION. BUFKIT SOUNDINGS INDICATE LOW CHANCES OF SNOW ACROSS OUR NORTH AND FREEZING PRECIPITATION SOUTH EARLY FRIDAY NIGHT AND WITH THICKNESS AND TEMPERATURES RISING SLOWLY OVERNIGHT WHICH SHOULD ALLOW CHANCES OF FREEZING RAIN TO SPREAD NORTH BY SATURDAY MORNING AND THEN PRECIPITATION BEING MOSTLY RAIN SATURDAY AFTERNOON. ALL MODELS INDICATE QUITE A BIT OF PRECIPITATION AROUND SATURDAY AND WENT WITH HPC PROGS WHICH INDICATED LIKELY POPS CENTRAL AND SOUTH SATURDAY. AFTER LOW PRESSURE GOES BY...MODELS INDICATE A CHANGEOVER BACK TO LIGHT SNOW OR FLURRIES SATURDAY NIGHT WITH RETURN OF COLDER AIR. WILL ALSO MENTION SLIGHT CHANCE OF SNOW SHOWERS WITH MIXED PRECIP FAR SOUTHEAST SUNDAY MORNING AND THEN DRY AFTER THAT AS COLD HIGH PRESSURE BUILDS BACK IN. MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING AS TEMPERATURES WILL BE NON-DIURNAL. OTHERWISE...MADE ONLY MINOR TWEAKS TO A MOS BLEND ON TEMPERATURES MOST OTHER PERIODS. && .AVIATION /DISCUSSION FOR THE 301800Z TAF ISSUANCE/... ISSUED AT 1147 AM EST TUE DEC 30 2014 MAINLY VFR CONDITIONS EXPECTED THROUGH MOST OF THE TAF PERIOD. THE ONE CAVEAT TO THAT IS THE SPORADIC FEW/SCT MVFR CEILINGS EXISTING WITHIN THE THIN BAND OF CLOUDS CURRENTLY EXTENDING DOWN FROM NORTH CENTRAL INDIANA THROUGH WEST CENTRAL INDIANA. UNDERNEATH SOME OF THE MORE CONCENTRATED CLOUD SHIELD...I.E. ABOVE AND SOUTHWEST OF HUF AND ABOVE AND NORTH OF LAF...BKN TO OVC MVFR CEILINGS ARE PERSISTING. EXPECT THOSE MVFR CEILINGS TO MOVE OUT OF LAF IN THE NEXT 2 HRS OR SO AND OUT OF HUF WITHIN THE NEXT 3 TO 4 HOURS. DO NOT CURRENTLY EXPECT TO SEE THOSE MVFR CEILINGS MAKE IT INTO IND OR BMG. HOWEVER...IT IS NOT OUTSIDE THE REALM OF POSSIBILITY OVER THE NEXT FEW HOURS AS CU FIELD IS THICKENING ACROSS WEST-CENTRAL AND CENTRAL PORTIONS OF CENTRAL INDIANA. ALONG WITH THE INCREASE IN CLOUDS...A GRADUAL BACKING OF WINDS TO THE NORTHWEST IS EXPECTED AS WELL. WOULD NOT BE SURPRISED TO SEE AN OB OR TWO FROM LAF WITH -SN SENSING FLURRIES WITHIN THE NEXT FEW HOURS AS WELL. OTHERWISE...EXPECT VFR CONDITIONS WITH FEW/SCT CU AND A SCATTERED MID-LEVEL DECK. MODEL SOUNDINGS CONTINUE TO INDICATE CLEARING OCCURRING TONIGHT AS ARCTIC HIGH PRESSURE BUILDS INTO THE GREAT PLAINS STATES. NORTH WINDS AROUND 10 KNOTS WILL BECOME NORTHWEST THIS AFTERNOON AND WEST AROUND 5 TO 7 KNOTS LATE TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...JK SHORT TERM...TDUD LONG TERM...JH AVIATION...MRD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
559 PM EST TUE DEC 30 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT MID/UPPER LEVEL RIDGE FROM THE ERN PACIFIC INTO BC AND A TROUGH OVER NE CANADA RESULTING IN NNW FLOW TOWARD NRN ONTARIO AND THE NRN LAKES. A SHORTWAVE TROUGH AXIS EXTENDED FROM JAMES BAY INTO SE NORTH DAKOTA. WITH ONLY WEAK FORCING AND LITTLE MOISTURE AVAILABLE...NO PCPN WAS ASSOCIATED WITH THIS FEATURE. FURTHER UPSTREAM...A STRONGER SHRTWV WAS MOVING THROUGH NRN SASK/MANITOBA. AT THE SFC...W TO WNW FLOW PREVAILED ACROSS UPPER MI AND LAKE SUPERIOR AS 1048 MB HIGH PRES CONTINUES TO SINK THROUGH THE NRN AND CNTRL PLAINS. EVEN WITH 850 MB TEMPS NEAR -23C...SATELLITE/RADAR INDICATED ONLY LIGHT TO MODERATE LES INTO NW UPPER MI AND EAST OF MUNISING AS INVERSION HEIGHTS REMAINED NEAR 4K FT WITH VERY DRY AIR UPSTREAM. TONIGHT...EXPECT WINDS TO GRADUALLY BACK TO SW AHEAD OF THE SASK/MANITOBA SHRTWV WHICH WILL PUSH THE LES MOSTLY OFFSHORE. HOWEVER...ADDITIONAL SNOWFALL AMOUNTS OF 1 TO 3 INCHES NW(KEWEENAW AND 2 TO 4 INCHES NE (NE OF P53) ARE POSSIBLE. TEMPS FALLING OFF INTO THE -7F TO -12F RANGE AND WINDS NEAR 10 MPH WILL DROP WIND CHILLS INTO THE -20 TO -33 RANGE OVER THE INTERIOR WRN HALF WHERE WIND CHILL ADVISORIES WILL REMAIN IN EFFECT. WEDNESDAY...AS THE SHRTWV MOVES THROUGH THE NRN LAKES AND DRAGS A WEAK TROUGH THE AREA...WINDS WILL VEER AGAIN FROM SW TO W BY AFTERNOON. THIS WILL BRING THE LES INTO THE NRN KEWEENAW BY MIDDAY AND INTO MUCH OF THE REST OF THE PENINSULA BY MID TO LATE AFTERNOON. THE COMBINATION OF THE LES AND WIND GUSTS OVER 40 MPH WILL LEAD TO VERY POOR VSBY WHICH WILL LINGER INTO THE EVENING...PROMPTING THE ISSUANCE OF AN LES ADVY. ALTHOUGH THERE WILL BE A PERIOD OF DEEPER MOISTURE THAT SHOULD INTENSIFY LES...THE SHIFTING WIND DIRECTIONS SHOULD LIMIT OVERALL AMOUNTS TO THE 1 TO 3 INCH RANGE BY EVENING. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 UPPER AIR PATTERN STARTS OUT WITH TROUGHING ANCHORED OVER HUDSON BAY AND ANOTHER MORE COMPACT TROUGH OVER DESERT SOUTHWEST OF CONUS. ONLY RIDGING OF NOTE IS OVER THE EASTERN PACIFIC OCEAN INTO FAR WESTERN CANADA. ATTENTION THIS WEEKEND WILL BE ON THE SOUTHWEST CONUS TROUGH. MODELS CONTINUE TO FAVOR IDEA THAT AS STRONG JET ENERGY ADVANCES AHEAD OF TROUGH...IT WILL EMERGE OVER THE SOUTHERN PLAINS ON SATURDAY AND LIFT OVER THE GREAT LAKES ON SUNDAY. MEANWHILE...ANOTHER SHORTWAVE WITHIN THE BASE OF LARGER TROUGHING OVER EASTERN CANADA WILL WORK OVER THE UPPER GREAT LAKES. ONE OR BOTH OF THESE FEATURES MAY BRING WIDESPREAD SNOW TO UPR MICHIGAN FRIDAY NIGHT THROUGH SATURDAY NIGHT. THERE IS POTENTIAL THAT THE TWO FEATURES COULD PHASE...THOUGH THAT IS NOT CERTAIN...AND THAT WOULD RESULT IN GREATEST CHANCE OF SEEING HIGHER END SNOW EVENT. NO MATTER HOW IT SHAKES OUT...THERE ARE INDICATIONS VERY CHILLY AIRMASS...EVEN COLDER THAN ONE CURRENTLY AFFECTING THE REGION...WILL SETTLE OVER UPR GREAT LAKES BY EARLY NEXT WEEK. BEYOND END OF EXTENDED THERE ARE SIGNALS THAT RIDGE OVER EAST PACIFIC BREAKS DOWN AND MORE MILD AIR RETURNS TO MUCH OF THE CONUS. PATTERN SHIFT THE CFSV2 HAS BEEN SHOWING FOR A WHILE NOW. THUS...OVERALL IT DOES NOT APPEAR THAT THE UPCOMING COLD WILL BE THAT LONG LASTING. INTIALLY THE MAIN ISSUE WILL BE THE ONGOING WEST FLOW LAKE EFFECT AND BLOWING SNOW WITH POOR VSBY OVER THE KEWEENAW. DECENT AGREEMENT THAT SHORTWAVE DROPPING WNW-ESE OVER LK SUPERIOR AND UPR MICHIGAN WEDNESDAY EVENING WITH LEADING SFC TROUGH AND ENHANCED CONVERGENCE AND ADDITIONAL MOISTURE WILL RESULT IN A A BRIEF PERIOD OF MODERATE TO HEAVY LES. WIND CORE MAX AT 950-925MB OVER 40 KTS WILL BE EASING BY WEDNESDAY EVENING...BUT MIXED LAYER WINDS UP TO 40 KTS WILL STILL RESULT IN STRONG/GUSTY WINDS OVER 30 MPH AND BLSN/POOR VSBY. SOUNDINGS SHOW MARGINAL MOISTURE AND INSTABILITY FOR SIGNIFICANT LES THOUGH AFTER THE TROUGH PASSAGE WITH INVERSIONS PEAKING AT 5-7 KFT AGL WEDNESDAY EVENING AND LAKE INDUCED EQL NOT MUCH HIGHER THAN THAT. MAJORITY OF THE MOIST LAYER IS WITHIN THE DGZ BUT STRONG WINDS WILL LIKELY CUT DOWN SLR/S. POOR VSBY WILL BE THE BIGGER STORY COMPARED TO SNOW AMOUNTS. AFTER COORDINATING WITH SHORT TERM FORECASTER... DECIDED TO GO WITH LAKE EFFECT SNOW ADVISORY FOR SNOW AND BLOWING SNOW WEDNESDAY AFTN THROUGH EARLY AFTERNOON ON NEW YEARS DAY. WILL MENTION OCCASIONAL WHITEOUT CONDITIONS IN THE WSW STATEMENT. LAKE EFFECT AND BLOWING SNOW BECOME FACTOR LATE WEDNESDAY NIGHT INTO THURSDAY FOR AREAS FAVORED BY WNW WINDS...ONTONAGON COUNTY OVER THE WEST AND IN THE SNOW BELTS OF EASTERN HALF OF UPR MICHIGAN. LOOKING AT ONLY A PURE LES SETUP AS SOUNDINGS SHOW SHARP DRYING ABOVE 8KFT. TEMPS AT TOP OF INVERSION BLO -20C LEAD TO MARGINAL INSTABILITY GIVEN WATER TEMPS 2-3C. MOST OF LAKE CONVECTIVE LAYER WILL BE IN THE DGZ AND WINDS WILL BE DIMINISHING...SO FLUFF FACTOR WILL PLAY MORE OF A ROLE. OVERALL...ADVY SNOW AMOUNTS SEEM POSSIBLE INTO NEW YEARS DAY FOR THE WNW FLOW AREAS. LAKE EFFECT LINGERS FOR WNW FLOW AREAS INTO FRIDAY...BUT WILL CONTINUE TO DIMINISH AS HIGH PRESSURE RIDGE SLIDES ACROSS WESTERN GREAT LAKES. COLD WILL SLOWLY EASE...THOUGH TEMPS WELL BLO ZERO EXPECTED THURSDAY NIGHT OVER INTERIOR CNTRL UPR MICHIGAN. INCREASE OF MID CLOUDS MAY RESULT IN LESS TEMP DROP OVER WEST CWA. MAIN QUESTION THIS WEEKEND IS HOW MUCH PHASING OCCURS BTWN APPROACHING NORTHERN STREAM SHORTWAVE TROUGH AND THE UPPER LOW OPENING UP AS IT LIFTS INTO THE CNTRL PLAINS FM THE SOUTHWEST CONUS. SINCE MAJORITY OF JET ENERGY REMAINS AHEAD OF THE SOUTHERN STREAM TROUGH...WOULD EXPECT IT TO STAY FAIRLY PROGRESSIVE AND HAVE LESS CHANCE OF PHASING WITH NORTHERN STREAM SYSTEM. EVEN SO...THE NORTHERN STREAM SHORTWAVE ALONG WITH INCREASING NNE-NNW FLOW WITH H85 TEMPS BLO -12C SATURDAY NIGHT INTO SUNDAY MAY LEAD TO SEVERAL INCHES OF SNOW. BEST SHOT OF SYNOPTIC SNOW WOULD BE OVER THE SOUTH AND EAST CWA WHILE THE GREATEST CHANCE FOR LAKE ENHANCEMENT WOULD BE OVER THE WEST AND NORTH CENTRAL CWA. TIGHT PRESSURE GRADIENT RESULTS IN GUSTY WINDS AND BLOWING SNOW AS WELL. MODEL TRENDS FOR THIS SYSTEM ARE VARIABLE WITH EARLIER RUNS A FEW DAYS AGO SHOWING A WRAPPED UP SYSTEM AND RECENT RUNS BACKING AWAY FM THAT. LATEST RUNS SEEM TO BE TRYING TO COME BACK TO AT LEAST A FARTHER WEST TRACK TO THE SOUTHERN STREAM SYSTEM IF NOT A MORE PHASED SYSTEM. SYSTEM BEARS WATCHING AS IT COULD RESULT IN SOME HEADLINES. BEHIND THE SYSTEM...LOOKS VERY COLD WITH H85 TEMPS DOWN TO -28C BY NEXT MONDAY. INCREASED POPS FOR LAKE EFFECT IN WNW-W FLOW AREAS. MAJORITY OF LAKE CONVECTIVE LAYER IS AT TEMPS BLO -20C...SO SLR/S WILL BE LOW AND MAIN PROBLEM COULD BE POOR VSBY. COULD ALSO HAVE WIND CHILL ISSUES FOR THE FIRST DAY BACK TO SCHOOL AFTER WINTER VACATION. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 559 PM EST TUE DEC 30 2014 LAKE EFFECT SNOW WILL FAVOR PERSISTENT MVFR CIGS AND IFR/LIFR VSBY AT CMX THROUGH THE PERIOD. GUSTY WINDS INTO WED MORNING WILL ALSO REDUCE VSBY WITH BLSN. LAKE EFFECT CLOUDS/SNOW WILL LIFT FAR ENOUGH TO THE NORTH FOR IMPROVING CONDITIONS TO VFR WHICH WILL LAST INTO WED AS WINDS BECOME WSW AT IWD. AT SAW...VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD. WILL GET GUSTY AT ALL SITES LATE TONIGHT THROUGH WED. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 427 PM EST TUE DEC 30 2014 WEST TO SOUTHWEST GALES 40-45 KTS ARE EXPECTED OVER MOST OF LK SUPERIOR BEGINNING LATER TONIGHT WILL SHIFT TO WEST-NORTHWEST GALES TO 35 KTS LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. IN ADDITION TO THE GALES... HEAVY FREEZING SPRAY WILL AFFECT MOST OF THE LAKE INTO THURSDAY. WINDS DIMINISH TO LESS THAN 25 KTS BY FRIDAY...BUT THE LULL WILL BE BRIEF AS NORTHERLY WINDS INCREASE TO GALES TO 40 KTS SATURDAY NIGHT INTO SUNDAY. MORE HEAVY FREEZING SPRAY WILL OCCUR AT THIS TIME AS WELL. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY FROM 9 PM EST /8 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ002-009-010-084. LAKE EFFECT SNOW ADVISORY FROM 1 PM WEDNESDAY TO 1 PM EST THURSDAY FOR MIZ001-003. LAKESHORE FLOOD ADVISORY FROM 6 AM WEDNESDAY TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ001-003. WIND CHILL ADVISORY FROM 11 PM EST /10 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ004-005-011-012. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263>267. GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ244- 245-264>267. GALE WARNING FROM 7 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ249>251. GALE WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246>248. HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246-247. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-241>243-263. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
429 PM EST TUE DEC 30 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT MID/UPPER LEVEL RIDGE FROM THE ERN PACIFIC INTO BC AND A TROUGH OVER NE CANADA RESULTING IN NNW FLOW TOWARD NRN ONTARIO AND THE NRN LAKES. A SHORTWAVE TROUGH AXIS EXTENDED FROM JAMES BAY INTO SE NORTH DAKOTA. WITH ONLY WEAK FORCING AND LITTLE MOISTURE AVAILABLE...NO PCPN WAS ASSOCIATED WITH THIS FEATURE. FURTHER UPSTREAM...A STRONGER SHRTWV WAS MOVING THROUGH NRN SASK/MANITOBA. AT THE SFC...W TO WNW FLOW PREVAILED ACROSS UPPER MI AND LAKE SUPERIOR AS 1048 MB HIGH PRES CONTINUES TO SINK THROUGH THE NRN AND CNTRL PLAINS. EVEN WITH 850 MB TEMPS NEAR -23C...SATELLITE/RADAR INDICATED ONLY LIGHT TO MODERATE LES INTO NW UPPER MI AND EAST OF MUNISING AS INVERSION HEIGHTS REMAINED NEAR 4K FT WITH VERY DRY AIR UPSTREAM. TONIGHT...EXPECT WINDS TO GRADUALLY BACK TO SW AHEAD OF THE SASK/MANITOBA SHRTWV WHICH WILL PUSH THE LES MOSTLY OFFSHORE. HOWEVER...ADDITIONAL SNOWFALL AMOUNTS OF 1 TO 3 INCHES NW(KEWEENAW AND 2 TO 4 INCHES NE (NE OF P53) ARE POSSIBLE. TEMPS FALLING OFF INTO THE -7F TO -12F RANGE AND WINDS NEAR 10 MPH WILL DROP WIND CHILLS INTO THE -20 TO -33 RANGE OVER THE INTERIOR WRN HALF WHERE WIND CHILL ADVISORIES WILL REMAIN IN EFFECT. WEDNESDAY...AS THE SHRTWV MOVES THROUGH THE NRN LAKES AND DRAGS A WEAK TROUGH THE AREA...WINDS WILL VEER AGAIN FROM SW TO W BY AFTERNOON. THIS WILL BRING THE LES INTO THE NRN KEWEENAW BY MIDDAY AND INTO MUCH OF THE REST OF THE PENINSULA BY MID TO LATE AFTERNOON. THE COMBINATION OF THE LES AND WIND GUSTS OVER 40 MPH WILL LEAD TO VERY POOR VSBY WHICH WILL LINGER INTO THE EVENING...PROMPTING THE ISSUANCE OF AN LES ADVY. ALTHOUGH THERE WILL BE A PERIOD OF DEEPER MOISTURE THAT SHOULD INTENSIFY LES...THE SHIFTING WIND DIRECTIONS SHOULD LIMIT OVERALL AMOUNTS TO THE 1 TO 3 INCH RANGE BY EVENING. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 UPPER AIR PATTERN STARTS OUT WITH TROUGHING ANCHORED OVER HUDSON BAY AND ANOTHER MORE COMPACT TROUGH OVER DESERT SOUTHWEST OF CONUS. ONLY RIDGING OF NOTE IS OVER THE EASTERN PACIFIC OCEAN INTO FAR WESTERN CANADA. ATTENTION THIS WEEKEND WILL BE ON THE SOUTHWEST CONUS TROUGH. MODELS CONTINUE TO FAVOR IDEA THAT AS STRONG JET ENERGY ADVANCES AHEAD OF TROUGH...IT WILL EMERGE OVER THE SOUTHERN PLAINS ON SATURDAY AND LIFT OVER THE GREAT LAKES ON SUNDAY. MEANWHILE...ANOTHER SHORTWAVE WITHIN THE BASE OF LARGER TROUGHING OVER EASTERN CANADA WILL WORK OVER THE UPPER GREAT LAKES. ONE OR BOTH OF THESE FEATURES MAY BRING WIDESPREAD SNOW TO UPR MICHIGAN FRIDAY NIGHT THROUGH SATURDAY NIGHT. THERE IS POTENTIAL THAT THE TWO FEATURES COULD PHASE...THOUGH THAT IS NOT CERTAIN...AND THAT WOULD RESULT IN GREATEST CHANCE OF SEEING HIGHER END SNOW EVENT. NO MATTER HOW IT SHAKES OUT...THERE ARE INDICATIONS VERY CHILLY AIRMASS...EVEN COLDER THAN ONE CURRENTLY AFFECTING THE REGION...WILL SETTLE OVER UPR GREAT LAKES BY EARLY NEXT WEEK. BEYOND END OF EXTENDED THERE ARE SIGNALS THAT RIDGE OVER EAST PACIFIC BREAKS DOWN AND MORE MILD AIR RETURNS TO MUCH OF THE CONUS. PATTERN SHIFT THE CFSV2 HAS BEEN SHOWING FOR A WHILE NOW. THUS...OVERALL IT DOES NOT APPEAR THAT THE UPCOMING COLD WILL BE THAT LONG LASTING. INTIALLY THE MAIN ISSUE WILL BE THE ONGOING WEST FLOW LAKE EFFECT AND BLOWING SNOW WITH POOR VSBY OVER THE KEWEENAW. DECENT AGREEMENT THAT SHORTWAVE DROPPING WNW-ESE OVER LK SUPERIOR AND UPR MICHIGAN WEDNESDAY EVENING WITH LEADING SFC TROUGH AND ENHANCED CONVERGENCE AND ADDITIONAL MOISTURE WILL RESULT IN A A BRIEF PERIOD OF MODERATE TO HEAVY LES. WIND CORE MAX AT 950-925MB OVER 40 KTS WILL BE EASING BY WEDNESDAY EVENING...BUT MIXED LAYER WINDS UP TO 40 KTS WILL STILL RESULT IN STRONG/GUSTY WINDS OVER 30 MPH AND BLSN/POOR VSBY. SOUNDINGS SHOW MARGINAL MOISTURE AND INSTABILITY FOR SIGNIFICANT LES THOUGH AFTER THE TROUGH PASSAGE WITH INVERSIONS PEAKING AT 5-7 KFT AGL WEDNESDAY EVENING AND LAKE INDUCED EQL NOT MUCH HIGHER THAN THAT. MAJORITY OF THE MOIST LAYER IS WITHIN THE DGZ BUT STRONG WINDS WILL LIKELY CUT DOWN SLR/S. POOR VSBY WILL BE THE BIGGER STORY COMPARED TO SNOW AMOUNTS. AFTER COORDINATING WITH SHORT TERM FORECASTER... DECIDED TO GO WITH LAKE EFFECT SNOW ADVISORY FOR SNOW AND BLOWING SNOW WEDNESDAY AFTN THROUGH EARLY AFTERNOON ON NEW YEARS DAY. WILL MENTION OCCASIONAL WHITEOUT CONDITIONS IN THE WSW STATEMENT. LAKE EFFECT AND BLOWING SNOW BECOME FACTOR LATE WEDNESDAY NIGHT INTO THURSDAY FOR AREAS FAVORED BY WNW WINDS...ONTONAGON COUNTY OVER THE WEST AND IN THE SNOW BELTS OF EASTERN HALF OF UPR MICHIGAN. LOOKING AT ONLY A PURE LES SETUP AS SOUNDINGS SHOW SHARP DRYING ABOVE 8KFT. TEMPS AT TOP OF INVERSION BLO -20C LEAD TO MARGINAL INSTABILITY GIVEN WATER TEMPS 2-3C. MOST OF LAKE CONVECTIVE LAYER WILL BE IN THE DGZ AND WINDS WILL BE DIMINISHING...SO FLUFF FACTOR WILL PLAY MORE OF A ROLE. OVERALL...ADVY SNOW AMOUNTS SEEM POSSIBLE INTO NEW YEARS DAY FOR THE WNW FLOW AREAS. LAKE EFFECT LINGERS FOR WNW FLOW AREAS INTO FRIDAY...BUT WILL CONTINUE TO DIMINISH AS HIGH PRESSURE RIDGE SLIDES ACROSS WESTERN GREAT LAKES. COLD WILL SLOWLY EASE...THOUGH TEMPS WELL BLO ZERO EXPECTED THURSDAY NIGHT OVER INTERIOR CNTRL UPR MICHIGAN. INCREASE OF MID CLOUDS MAY RESULT IN LESS TEMP DROP OVER WEST CWA. MAIN QUESTION THIS WEEKEND IS HOW MUCH PHASING OCCURS BTWN APPROACHING NORTHERN STREAM SHORTWAVE TROUGH AND THE UPPER LOW OPENING UP AS IT LIFTS INTO THE CNTRL PLAINS FM THE SOUTHWEST CONUS. SINCE MAJORITY OF JET ENERGY REMAINS AHEAD OF THE SOUTHERN STREAM TROUGH...WOULD EXPECT IT TO STAY FAIRLY PROGRESSIVE AND HAVE LESS CHANCE OF PHASING WITH NORTHERN STREAM SYSTEM. EVEN SO...THE NORTHERN STREAM SHORTWAVE ALONG WITH INCREASING NNE-NNW FLOW WITH H85 TEMPS BLO -12C SATURDAY NIGHT INTO SUNDAY MAY LEAD TO SEVERAL INCHES OF SNOW. BEST SHOT OF SYNOPTIC SNOW WOULD BE OVER THE SOUTH AND EAST CWA WHILE THE GREATEST CHANCE FOR LAKE ENHANCEMENT WOULD BE OVER THE WEST AND NORTH CENTRAL CWA. TIGHT PRESSURE GRADIENT RESULTS IN GUSTY WINDS AND BLOWING SNOW AS WELL. MODEL TRENDS FOR THIS SYSTEM ARE VARIABLE WITH EARLIER RUNS A FEW DAYS AGO SHOWING A WRAPPED UP SYSTEM AND RECENT RUNS BACKING AWAY FM THAT. LATEST RUNS SEEM TO BE TRYING TO COME BACK TO AT LEAST A FARTHER WEST TRACK TO THE SOUTHERN STREAM SYSTEM IF NOT A MORE PHASED SYSTEM. SYSTEM BEARS WATCHING AS IT COULD RESULT IN SOME HEADLINES. BEHIND THE SYSTEM...LOOKS VERY COLD WITH H85 TEMPS DOWN TO -28C BY NEXT MONDAY. INCREASED POPS FOR LAKE EFFECT IN WNW-W FLOW AREAS. MAJORITY OF LAKE CONVECTIVE LAYER IS AT TEMPS BLO -20C...SO SLR/S WILL BE LOW AND MAIN PROBLEM COULD BE POOR VSBY. COULD ALSO HAVE WIND CHILL ISSUES FOR THE FIRST DAY BACK TO SCHOOL AFTER WINTER VACATION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1249 PM EST TUE DEC 30 2014 LAKE EFFECT SNOW WILL FAVOR PERSISTENT MVFR CIGS AND IFR/LIFR VSBY AT CMX UNTIL LATE TONIGHT WHEN WINDS BACKING TO SAW WILL PUSH THE LES BANDS OFFSHORE. GUSTY WINDS INTO WED MORNING WILL ALSO REDUCE VSBY WITH BLSN EVEN AS THE LES REMAINS MAINLY OFFSHORE. LAKE EFFECT CLOUDS/SNOW WILL REMAIN NEAR IWD THROUGH THIS AFTERNOON BUT MAY LIFT FAR ENOUGH TO THE NORTH FOR IMPROVING CONDITIONS TO VFR WHICH WILL LAST INTO WED AS WINDS BECOME WSW. AT SAW...MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES WILL ALSO GIVE WAY TO CLEARING WITH VFR CONDITIONS THIS EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 427 PM EST TUE DEC 30 2014 WEST TO SOUTHWEST GALES 40-45 KTS ARE EXPECTED OVER MOST OF LK SUPERIOR BEGINNING LATER TONIGHT WILL SHIFT TO WEST-NORTHWEST GALES TO 35 KTS LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. IN ADDITION TO THE GALES... HEAVY FREEZING SPRAY WILL AFFECT MOST OF THE LAKE INTO THURSDAY. WINDS DIMINISH TO LESS THAN 25 KTS BY FRIDAY...BUT THE LULL WILL BE BRIEF AS NORTHERLY WINDS INCREASE TO GALES TO 40 KTS SATURDAY NIGHT INTO SUNDAY. MORE HEAVY FREEZING SPRAY WILL OCCUR AT THIS TIME AS WELL. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY FROM 9 PM EST /8 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ002-009-010-084. LAKE EFFECT SNOW ADVISORY FROM 1 PM WEDNESDAY TO 1 PM EST THURSDAY FOR MIZ001-003. WIND CHILL ADVISORY FROM 11 PM EST /10 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ004-005-011-012. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263>267. GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ244- 245-264>267. GALE WARNING FROM 7 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ249>251. GALE WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246>248. HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246-247. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-241>243-263. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1233 PM CST TUE DEC 30 2014 .UPDATE... ISSUED AT 1235 PM CST TUE DEC 30 2014 WE HAVE LET THE WIND CHILL ADVISORY EXPIRE. WIND CHILLS WILL STILL HOVER NEAR 20 BELOW FOR MOST AREAS TODAY...SO STILL COLD. WE MAY NEED A WIND CHILL ADVISORY ONCE AGAIN OVERNIGHT AS WINDS INCREASE FROM THE WEST...SO WILL MONITOR THIS THREAT. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DON/T FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASURABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1230 PM CST TUE DEC 30 2014 MOSTLY CLEAR SKIES EXPECT THIS AFTN AND TONIGHT. MAIN AVIATION ISSUE WILL BE WINDS INCREASING OVERNIGHT...BECOMING WSW AND BREEZY ESPECIALLY ACROSS NORTHEASTERN ND. VFR CONDITIONS EXPECTED THROUGHOUT 18Z TAF PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...DK SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
408 PM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE AND A DRY AIRMASS WILL REMAIN IN PLACE ACROSS THE AREA THROUGH FRIDAY. A LOW PRESSURE SYSTEM WILL LIFT NORTHEAST ACROSS THE REGION THIS WEEKEND...BRINGING THE NEXT CHANCE FOR PRECIPITATION. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... INCREASING LOW LEVEL LAPSE RATES ACROSS NORTHERN INDIANA AND NORTHWEST OHIO HAVE LED TO SOME SCATTERED SNOW SHOWER/FLURRY DEVELOPMENT THIS AFTERNOON. THIS MAY BECOME A BIT MORE WIDESPREAD ACROSS OUR NORTHWEST OVER THE NEXT HOUR OR SO BUT WOULD EXPECT TO SEE A DOWNTURN IN COVERAGE THROUGH THE EVENING HOURS AS THE LOW LEVEL LAPSE RATES BEGIN TO DECREASE AGAIN. WILL THEREFORE JUST INCLUDE A CHANCE OF A FLURRY ACROSS PARTS OF OUR NORTHWEST THROUGH MID EVENING. THE CLOUDS ARE ALSO LOOKING FAIRLY DIURNAL ON THE VISIBLE SATELLITE IMAGERY SO WOULD EXPECT TO SEE SOME DISSIPATION IN THE CLOUDS THROUGH THE EVENING HOURS TOO. WILL TREND TOWARD A PARTLY CLOUDY SKY NORTH TO MOSTLY CLEAR IN THE SOUTH FOR LATER TONIGHT. EXPECT OVERNIGHT LOWS DOWN INTO THE TEENS ACROSS THE AREA. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AN ELONGATED AXIS OF SURFACE HIGH PRESSURE WILL REMAIN STRETCHED ACROSS THE OHIO AND TENNESSEE VALLEYS WEDNESDAY INTO THURSDAY. WITH A DRY AIRMASS IN PLACE...EXPECT MAINLY CLEAR SKIES THROUGH MUCH OF THE SHORT TERM PERIOD. WEAK LOW LEVEL CAA WILL CONTINUE INTO WEDNESDAY AND ALLOWING FOR MIXING UP TO ABOUT 900 MB ONLY YIELDS HIGHS RANGING FROM THE LOWER 20S NORTH TO MID/UPPER 20S SOUTH. LOW LEVEL FLOW WILL BEGIN TO SLOWLY BACK WEDNESDAY NIGHT INTO THURSDAY...LEADING TO SOME WEAK DEVELOPING WAA. EXPECT HIGHS ON THURSDAY RANGING FROM THE UPPER 20S NORTH TO LOW/MID 30S SOUTH. THIS WILL ALSO LEAD TO A GRADUAL INCREASING IN CLOUDS FROM THE SOUTH THROUGH THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE CLOSED LOW IN PLACE ACROSS THE SOUTHWEST CONUS EARLIER IN THE WEEK WILL BE MOVING ACROSS THE FOUR CORNERS REGION TOWARD THE PLAINS ON FRIDAY. MODEL RUNS OVER THE PAST COUPLE DAYS HAVE BEEN RATHER CONSISTENT WITH THIS MOVEMENT OF THE UPPER LOW...AS WELL AS DEVELOPING A SOUTHERLY FLOW OUT OF THE GULF OF MEXICO AT THE SAME TIME. MOISTURE SHOULD REMAIN LIMITED ENOUGH FRIDAY AND FRIDAY NIGHT ACROSS THE AREA...AND CONFLUENT FLOW ALOFT WILL BE IN PLACE...SO ONLY A SLIGHT CHANCE OF RAIN AND SNOW IS INCLUDED IN THE FORECAST...MAINLY OVER THE SOUTHERN COUNTIES OF THE AREA. INCONSISTENCIES ACROSS THE MODELS HAVE BEEN MUCH MORE ABUNDANT WITH THE HANDLING OF THE UPPER LOW AS IT EMERGES INTO THE PLAINS STATES ON SATURDAY. AFTER SUGGESTING YESTERDAY THAT PHASING OF NORTHERN AND SOUTHERN STREAM ENERGY MAY NOT HAPPEN...RUNS LAST NIGHT AND TODAY ARE SUGGESTING THIS PHASING MAY INDEED OCCUR. THE 12Z RUNS HAVE ALL PRETTY MUCH COME IN SUPPORTING PHASING AND A SURFACE LOW TRACK INTO THE OHIO VALLEY AND GREAT LAKES FROM SATURDAY AFTERNOON THROUGH SUNDAY. THIS SOLUTION WOULD SUPPORT THE DEVELOPMENT OF A WINTRY MIX OF PRECIPITATION LATE FRIDAY NIGHT AND SATURDAY MORNING ACROSS THE AREA...BEFORE CHANGING OVER TO RAIN BY LATER SATURDAY AFTERNOON. BUFKIT SOUNDINGS INDICATE ENOUGH COLD AIR SHOULD INITIALLY BE IN PLACE AT THE SURFACE FOR SOME FREEZING RAIN TO DEVELOP LATE FRIDAY NIGHT AND SATURDAY MORNING WITH THIS PARTICULAR STORM TRACK. ONLY A MIX OF RAIN AND SNOW WILL BE INCLUDED IN THIS FORECAST PACKAGE FOR NOW...PENDING MORE AGREEMENT ON THE SYSTEM TRACK FROM FUTURE MODEL RUNS. RAIN MAY CHANGE BACK TO SOME SNOW AS PRECIPITATION PULLS OUT OF THE AREA SUNDAY...WITH TEMPERATURES COOLING BACK BELOW NORMAL. THE 12Z MODELS ARE TRYING TO RESOLVE A COUPLE OF DISTURBANCES ROTATING THROUGH CYCLONIC FLOW EARLY NEXT WEEK. THESE IMPULSES COULD BRING CHANCES FOR LIGHT SNOW TO THE AREA MONDAY AND TUESDAY. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... VFR SKC OR JUST FEW CLOUDS THROUGH 21-00Z...AND THEN BOTH RAP AND NAM PICK UP THE MVFR CIGS OVER INDIANA FAIRLY WELL AT THIS TIME...SO CONTINUING WITH THE PREVIOUS FORECAST OF MVFR CIGS IN THE 00Z-08Z TIMEFRAME...THOUGH THIS IS SLIGHTLY ON THE PESSIMISTIC SIDE AS ADVECTION OF MOISTURE OFF LAKE MI STOPPING OVERNIGHT AS THE SFC HIGH BUILDS IN AND THE MOISTURE FLOW CUTS OFF. SCATTERING/LIFING OF THE MVFR CLOUDS MAY OCCUR EARLIER. SOME POTENTIAL AT KDAY/KCMH/KLCK FOR MVFR CIGS TO DROP BELOW THE 2K FT FUEL ALTERNATE CRITERIA THRESHOLD IN THE 02Z-08Z TIMEFRAME. AFTER THIS LL MOISTURE PUSHES EAST...FLOW BACKS TO THE SW WITH SLIGHTLY INCREASED WINDS. OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE ON SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...SHOBE2 AVIATION...JDR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 PM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE WILL KEEP A DRY CONIDITIONS OVER THE OHIO VALLEY THROUGH FRIDAY. ON FRIDAY NIGHT...LOW PRESSURE FROM THE SOUTHERN PLAINS WILL TRACK TOWARD THE LOWER OHIO VALLEY AT THE SAME TIME A LOW PRESSURE WILL TRACK TOWARD THE GREAT LAKES FROM THE NORTHERN PLAINS. THE COMBINATION OF THESE TWO SYSTEMS WILL BRING PRECIPITATION TO THE REGION FRIDAY NIGHT INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONTINUED SUN...BUT WITH SOME LAKE EFFECT CLOUDS TO AFFECT THE NORTHERN FCST AREA AS THE AFTERNOON PROGRESSES. WITH THIS AMOUNT OF SUN...TEMPS IN ESPECIALLY THE SOUTHERN FCST AREA CLIMBING A BIT MORE THAN ANTICIPATED SO HAVE RAISED HIGHS SLIGHTLY HERE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... HIGH PRESSURE WILL DIVE SOUTHWARD FROM THE NORTHERN PLAINS TODAY TO OKLAHOMA WEDNESDAY AND THEN SETTLE OVER THE GULF STATES THURSDAY. THE HIGH WILL THEN LIFT NORTHWARD THROUGH THE TENNESSEE VALLEY TO THE OHIO VALLEY BY FRIDAY EVENING. GENERALLY DRY CONDITIONS AND MOSTLY CLEAR SKIES WILL OCCUR FOR THE REGION THROUGH THIS TIME. THE ARCTIC AIR WILL BE AT ITS HEIGHT OVER THE REGION TONIGHT THROUGH WEDNESDAY NIGHT WITH LOWS IN THE TEENS AND HIGHS IN THE 20S. THE AIRMASS WILL BEGIN TO MODERATE AFTER THIS TIME WITH A GRADUAL RISE IN BOTH DAYTIME HIGHS AND NIGHTTIME LOWS FOR EACH PERIOD. THE NEXT SHOT OF PRECIPITATION WILL BEGIN LATE FRIDAY NIGHT AS A WARM FRONT PASSES OVER THE REGION ASSOCIATED WITH LOW PRESSURE EJECTING NORTHEAST FROM THE WESTERN GULF. && .LONG TERM /SATURDAY THROUGH MONDAY/... THE PERIOD BEGINS WITH SURFACE HIGH PRESSURE ACROSS THE LOWER MISSISSIPPI VALLEY THURSDAY AND THURSDAY NIGHT. THIS FEATURE WILL KEEP DRY CONDITIONS ACROSS THE AREA WITH BELOW NORMAL TEMPERATURES. THE MAIN QUESTION FOR THIS FORECAST CONTINUES TO BE THE EVOLUTION OF THE SOUTHWEST CONUS UPPER LOW. MODEL RUNS FROM THE PAST COUPLE DAYS HAVE GENERALLY SLOWED THE EJECTION OF THIS LOW...WITH THE FEATURE NOT REALLY LEAVING THE FOUR CORNERS ON THE 12Z RUNS UNTIL FRIDAY NIGHT. SOME MOISTURE IS SHOWN RETURNING FRIDAY FROM THE GULF TOWARD THE OHIO VALLEY WELL AHEAD OF THE UPPER LOW...THOUGH CONFLUENT FLOW ALOFT SHOULD COUNTERACT THE DEVELOPMENT OF PRECIPITATION ACROSS THE AREA. ENOUGH LIFT AND MOISTURE MAY BE IN PLACE BY FRIDAY NIGHT TO PRODUCE SOME RAIN AND SNOW...ESPECIALLY ACROSS THE SOUTHERN PORTION OF THE AREA. THAT CHANCE WILL CONTINUE INTO SATURDAY...THOUGH THE 12Z ECMWF/PARALLEL GFS ARE INDICATING THE BEST MOISTURE AND SURFACE LOW DEVELOPMENT WILL REMAIN SOUTH OF THE AREA. THE 12Z GFS AND GFS ENSEMBLE STILL SHOW THIS SYSTEM PROPAGATING TOWARD THE OHIO VALLEY...THOUGH THE STRENGTH OF THE UPPER LOW IN PLACE OVER HUDSON BAY MAY JUST BE ENOUGH TO BRUSH THIS SYSTEM MORE EAST ALONG THE LINES OF THE ECMWF/PARALLEL GFS. THIS SOLUTION WOULD STILL KEEP CHANCES OF RAIN AND SNOW ACROSS THE AREA THROUGH SUNDAY...THOUGH MORE FOCUSED ON THE THE SOUTHERN COUNTIES. ALL OF THE MODELS TEND TO PULL PRECIPITATION OUT OF THE AREA BY SUNDAY NIGHT...WITH GENERALLY DRY CONDITIONS IN PLACE MONDAY. TEMPERATURES SHOULD BE NEAR TO SOMEWHAT BELOW NORMAL AT THE END OF THE PERIOD. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... VFR SKC OR JUST FEW CLOUDS THROUGH 21-00Z...AND THEN BOTH RAP AND NAM PICK UP THE MVFR CIGS OVER INDIANA FAIRLY WELL AT THIS TIME...SO CONTINUING WITH THE PREVIOUS FORECAST OF MVFR CIGS IN THE 00Z-08Z TIMEFRAME...THOUGH THIS IS SLIGHTLY ON THE PESSIMISTIC SIDE AS ADVECTION OF MOISTURE OFF LAKE MI STOPPING OVERNIGHT AS THE SFC HIGH BUILDS IN AND THE MOISTURE FLOW CUTS OFF. SCATTERING/LIFING OF THE MVFR CLOUDS MAY OCCUR EARLIER. SOME POTENTIAL AT KDAY/KCMH/KLCK FOR MVFR CIGS TO DROP BELOW THE 2K FT FUEL ALTERNATE CRITERIA THRESHOLD IN THE 02Z-08Z TIMEFRAME. AFTER THIS LL MOISTURE PUSHES EAST...FLOW BACKS TO THE SW WITH SLIGHTLY INCREASED WINDS. OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE ON SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JDR NEAR TERM...JDR SHORT TERM...FRANKS LONG TERM...SHOBE2 AVIATION...JDR
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
258 PM MST TUE DEC 30 2014 .SYNOPSIS... A COLD FRONT PUSHED WEST ACROSS MUCH OF THE BORDERLAND TODAY... LEAVING IN IT`S WAKE COLD AIR AND INCREASING LOW CLOUDS FOR TONIGHT. A PACIFIC FRONTAL SYSTEM WILL MOVE TO WESTERN ARIZONA WEDNESDAY. THIS WILL PUSH CLOUDS IN AND KICK OFF SNOW SHOWERS OVER THE GILA AND RAIN SHOWERS OVER THE LOWLANDS. MOST OF THIS ACTIVITY WILL END THURSDAY FOR A BRIEF PERIOD BEFORE THE MAIN UPPER LOW MOVES OVER THE AREA FRIDAY. THIS WILL SPREAD MORE RAIN AND SNOW SHOWERS...WITH THE SACRAMENTO MOUNTAINS LIKELY SEEING HEAVY SNOW. MUCH OF THE LOWLANDS COULD SEE A MIX OF RAIN AND SNOW BUT LITTLE OR NO ACCUMULATION. THE LOW EXITS THE AREA FRIDAY NIGHT ALLOWING SKIES TO CLEAR. THROUGH MID WEEK OF NEXT WEEK...THE PATTERN LOOKS TO REMAIN A DRY WITH TEMPERATURES POSSIBLY BACK ABOVE NORMAL BY MONDAY. && .DISCUSSION... COMPLEX WINTER WEATHER PATTERN TO CONTINUE OVER THE NEXT 3 DAYS. MODELS HAVE BEEN RELATIVELY CLOSE...BUT 12Z GFS RUN THROUGH SOME DOUBT INTO FRIDAY SOLUTION. OTHERWISE FEW CHANGES MADE TO PREVIOUS FORECAST PACKAGE. BACK DOOR COLD FRONT SWEPT THROUGH THE RIO GRANDE VALLEY THIS MORNING. SFC OBS SHOW FRONT MAYBE OUT TO THE ARIZONA BORDER. COOL AIR LIKELY SHALLOW FROM DEMING WEST AS THOSE LOCATIONS WERE STILL ABLE TO MODIFY THIS AFTERNOON. EXTENSIVE LOW CLOUDS HAVE BEEN DAMMED UP AGAINST EASTERN TERRAIN ALL DAY. CLOUDS COVERED THE EASTERN SACS AND ARE SLOWLY SEEPING INTO HUDSPETH COUNTY. SOME FREEZING FOG HAS BEEN REPORTED...BUT PROG SOUNDINGS SUPPORT VERY LITTLE IN THE WAY OF PRECIP OVERNIGHT. WILL KEEP FREEZING FOG ADV OUT FOR EASTERN SACS AND ALSO ADD HUDSPETH COUNTY TO THE ADVISORY. TYPICAL PATTERN IS FOR LOW CLOUDS TO ACCELERATE WESTWARD AFTER SUNSET. HRRR ALSO SHOWS THIS...CLOUDING EL PASO CO OVER AROUND 6-7 PM...AND MOST OF THE REST OF THE LOWLANDS TO THE DIVIDE BY AROUND MIDNIGHT. LOW CLOUDS AND EAST PUSH WILL SLOWLY DIMINISH WEDNESDAY AS MAIN UPPER LOW DESCENDS DOWN TO WESTERN ARIZONA AND SURFACE GRADIENT BEGINS TO RELAX. NOT EXPECTING MUCH OF ANY PRECIP WEDNESDAY THOUGH KEEPING LOW POPS IN SEEMS PRUDENT. PACIFIC UPPER LOW AND SURFACE FRONT CONTINUE ADVANCING EAST. UPPER LOW PROGGED OVER EASTERN ARIZONA THURSDAY MORNING...WITH ATTENDANT FRONT PUSHING EAST ACROSS THE CWA. THIS WILL PRODUCE ANOTHER PERIOD SHOWERS...WITH SNOW LEVELS MOSTLY ABOVE 5000 FT. WILL ISSUED WINTER WEATHER ADV FOR THE GILA ZONES AS THIS SYSTEM LIKELY TO DROP DECENT SNOWFALL OVER THAT AREA. SHOULD SEE BRIEF END TO PRECIP THURSDAY NIGHT AS UPPER LOW LIFTS INTO COLORADO AND FRONT IS EAST OF THE AREA. HANG BACK LOW FORMS SOUTHWEST OF ORIGINAL LOW AND WILL MOVE OVER SOUTHERN NEW MEXICO FRIDAY. THIS IS WHERE THE 12Z GFS RUN DEVIATES FROM THE OTHER MODELS. NAM/ECMWF STILL SHOWING STRONG PRESENCE OF THIS LOW WITH HEAVY SNOW OVER THE SACS AND RAIN/SNOW OVER THE LOWLANDS. WILL STILL KEEP THIS THINKING FOR NOW. SNOW LEVELS FRIDAY LIKELY AT 4500-5000 FT SO SOME OF THE LOWLANDS COULD GET LIGHT SNOW ACCUMULATIONS. MOST FAVORED AREA NORTH AND WEST OF LAS CRUCES WILL HAVE TO BE WATCHED FOR POTENTIAL ADVISORIES. BELIEVE THE SACS WILL GET HEAVY SNOW BUT TOO EARLY TO ISSUE AT THIS TIME...ESPECIALLY WITH THE GFS UNCERTAINTY. UPPER LOW EXITS FRIDAY NIGHT WITH CLEARING TO FOLLOW. SATURDAY THROUGH TUESDAY PERIOD SHOULD REMAIN DRY AS WEST COAST UPPER RIDGE PERSISTS. TEMPERATURES SHOULD SLOWLY WARM BACK TO NORMAL BY MONDAY AND TUESDAY. && .AVIATION...VALID 31/00Z-01/00Z... THRU 06Z...P6SM FEW-SCT020 SCT-BKN150-200. AFT 06Z MOISTURE WILL BE PUSHING WESTWARD WITH SCT-BKN010-020 BKN-OVC120-150 DEVELOPING AT ALL TAF SITES WITH VERY PATCHY FZDZ POSSIBLE...MAINLY EAST OF KELP AND POSSIBLY TOWARD KTCS. LOW CLOUDS WILL REMAIN IN PLACE EAST OF RIO GRANDE...BUT POSSIBLY BECOME MORE SCT AFT 18Z WEST OF RIVER. E TO NE WINDS 10-20G30KTS THRU PD...STRONGEST ON WESTERN MOUNTAIN SLOPES. && .FIRE WEATHER... COLD FRONT HAS MOVED THROUGH THE REGION WITH GUSTY EAST WINDS IN PLACE WHICH WILL CONTINUE THROUGH WEDNESDAY. VERY LIGHT PRECIPITATION IN THE FORM OF FREEZING DRIZZLE IS POSSIBLE FAR NORTH AND EAST TONIGHT...BUT DEEPER LOW LEVEL MOISTURE WILL BE PUSHING WEST THROUGH THE NIGHT. SNOW IS EXPECTED OVER THE GILA REGION STARTING WEDNESDAY NIGHT AND OVER THE SACS MAINLY LATE THURSDAY INTO FRIDAY. SEVERAL INCHES OF SNOW ARE POSSIBLE IN EACH OF THESE MOUNTAIN ZONES. LOWLANDS COULD SEE A MIX OF RAIN AND SNOW WITH ANY ACCUMULATIONS REMAINING UNDER AN INCH. EXPECT BELOW NORMAL TEMPERATURES TO REMAIN IN PLACE THROUGH THE WEEKEND BEFORE WARMER AIR RETURNS EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 29 43 35 50 31 / 0 0 10 20 20 SIERRA BLANCA 24 36 29 46 30 / 20 20 10 20 20 LAS CRUCES 26 42 31 46 30 / 0 0 10 30 30 ALAMOGORDO 25 42 31 48 29 / 20 0 20 20 30 CLOUDCROFT 20 33 22 36 23 / 30 20 20 40 50 TRUTH OR CONSEQUENCES 25 42 30 42 26 / 10 20 30 30 30 SILVER CITY 25 41 28 37 25 / 0 10 50 50 30 DEMING 27 44 30 44 27 / 0 0 20 30 30 LORDSBURG 28 45 31 43 26 / 0 10 40 40 20 WEST EL PASO METRO 30 43 36 48 35 / 0 0 10 20 20 DELL CITY 22 33 28 45 25 / 20 20 20 20 20 FORT HANCOCK 26 41 33 51 29 / 10 10 10 10 20 LOMA LINDA 24 38 29 45 32 / 20 10 10 20 30 FABENS 27 42 34 49 29 / 0 0 10 20 20 SANTA TERESA 26 44 32 48 30 / 0 0 10 20 20 WHITE SANDS HQ 27 40 33 46 32 / 0 0 10 20 30 JORNADA RANGE 21 43 25 45 25 / 0 0 10 30 30 HATCH 25 44 30 46 28 / 0 10 20 30 30 COLUMBUS 30 45 34 45 32 / 0 0 10 30 20 OROGRANDE 25 40 30 46 30 / 10 0 10 20 30 MAYHILL 18 30 22 38 26 / 50 30 30 40 30 MESCALERO 18 34 22 40 24 / 30 20 20 40 50 TIMBERON 20 33 22 38 25 / 20 20 20 40 40 WINSTON 22 39 24 39 21 / 20 20 50 60 30 HILLSBORO 25 42 28 41 26 / 10 20 30 40 30 SPACEPORT 21 44 25 45 24 / 0 10 20 30 30 LAKE ROBERTS 24 42 25 37 24 / 0 20 60 70 30 HURLEY 25 42 28 40 26 / 0 10 40 40 20 CLIFF 22 47 31 40 20 / 0 10 70 60 20 MULE CREEK 19 46 24 38 17 / 0 10 80 70 30 FAYWOOD 27 41 30 40 28 / 0 10 30 40 30 ANIMAS 30 50 34 47 28 / 0 0 40 30 20 HACHITA 26 46 29 45 26 / 0 0 30 30 20 ANTELOPE WELLS 29 53 33 50 28 / 0 0 20 30 20 CLOVERDALE 32 55 34 46 27 / 0 0 40 40 30 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...FREEZING FOG ADVISORY FROM 7 PM THIS EVENING TO 11 AM MST WEDNESDAY FOR NMZ417. WINTER WEATHER ADVISORY FROM 6 PM WEDNESDAY TO 11 AM MST THURSDAY FOR NMZ401>403-408. WIND ADVISORY UNTIL 11 AM MST WEDNESDAY FOR NMZ411. FREEZING FOG ADVISORY UNTIL 11 AM MST WEDNESDAY FOR NMZ416. TX...FREEZING FOG ADVISORY FROM 7 PM THIS EVENING TO 11 AM MST WEDNESDAY FOR TXZ420>424. WIND ADVISORY UNTIL 11 AM MST WEDNESDAY FOR TXZ418. && $$ HEFNER/GRZYWACZ
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1216 PM CST TUE DEC 30 2014 .UPDATE... COLDER AND SOMEWHAT DRIER AIR BEHIND THE ARCTIC COLD FRONT THAT PASSED ABOUT MID MORNING. WINDS ALSO SLIGHTLY MORE NORTHERLY. PRECIPITATION REMAINS LIGHT BUT ENOUGH FOR A LIGHT GLAZE ALMOST EVERYWHERE...AND LATELY OVER SOUTHERN PART OF THE ROLLING PLAINS. WIND CHILLS HAVE REMAINED BELOW MINUS 5 ACROSS NORTHWEST ZONES WITH WINDS ONLY SLIGHTLY LOWER WHILE TEMPERATURES UNLIKELY TO RISE THIS AFTERNOON. WE HAVE ADDED THE SOUTHERN PART OF THE ROLLING PLAINS TO THE WINTER WEATHER ADVISORY NOW UNTIL 3 PM. ALSO ISSUED A WIND CHILL ADVISORY FOR THE NORTHWEST UNTIL 3. MOST SOLUTIONS CONTINUE TO GENERATE LIGHT PRECIPITATION TONIGHT PERHAPS SLIGHTLY FAVORING SOUTHEAST ZONES BUT NOT CLEAR YET. RMCQUEEN && .AVIATION... WITH DRIER COLDER AIR MOVING IN WE EXPECT CEILINGS TO INCH BACK TO NEAR LOWER END OF MVFR CEILINGS LATER TODAY. SOLUTIONS STILL SUGGEST LOWERING CONDITIONS MAY BECOME PERVASIVE OVERNIGHT WITH EXPANDING LIGHT PRECIPITATION FOR KLBB AND KPVW BUT NOT CERTAIN ENOUGH EITHER FOR A CHANGE OR TEMPO GROUP. RMCQUEEN && .PREV DISCUSSION... /ISSUED 921 AM CST TUE DEC 30 2014/ UPDATE... ISSUED A WINTER WEATHER ADVISORY FOR FREEZING DRIZZLE ON THE CAPROCK UNTIL NOON. MAY NEED TO EXTEND THIS AFTERNOON...AND IF SO WILL CONSIDER GOING THROUGH MUCH OF THE NIGHT. VERY COLD AIR MOVING SOUTHWARD SHOULD CHANGE FREEZING DRIZZLE MORE TO LIGHT SNOW AND PERHAPS LESS ICE ACCUMULATIONS BUT NOT CERTAIN AT THIS TIME. RMCQUEEN PREV DISCUSSION... /ISSUED 544 AM CST TUE DEC 30 2014/ UPDATE... KLBB 88D SHOWING THE EXPANSION OF VERY LIGHT REFLECTIVTY /ZERO TO MINUS 15 DBZ/ BTWN 1000 AND 5000 FT AGL AND LOWERING WITH TIME. THIS SHOULD BE THE PERIOD OF VERY LIGHT FLURRIES AND/OR FREEZING DRIZZLE ASSOCIATED WITH FRONTOGENTICAL FORCING. PER THE HRRR THIS PRECIP SHOULD SHIFT SWD WITH THE FORCING THROUGH THE MORNING. EXPECTATION IS IT SHOULD REMAIN TOO LIGHT CAUSE MUCH IN THE WAY OF DIFFICULTY THIS MORNING...BUT WILL CONTINUE TO MONITOR TRENDS. AVIATION... CIGS TO LOWER A BIT MORE DURING THE FIRST PART OF THE FCST PERIOD BUT SHOULD REMAIN MVFR THEN REMAIN PRETTY STABLE THROUGH THE REMAINDER OF THE PERIOD. ANTICIPATE SOME PERIODS OF LIGHT FREEZING DRIZZLE AND/OR FLURRIES THROUGH THE FCST TIME AS WELL. GUSTY NNE WINDS THROUGH MUCH OF THE DAY SHOULD RELAX TOWARD EVENING. PREV DISCUSSION... /ISSUED 428 AM CST TUE DEC 30 2014/ SHORT TERM... THE COLD FRONT IS NOW WELL INTO THE PERMIAN BASIN AND BIG COUNTRY WITH MUCH COLDER AIR FILTERING IN BEHIND IT RATHER THAN SURGING AT THIS POINT. WITH A GOOD STRATUS DECK NOW IN PLACE...ALTHOUGH NOT TERRIBLY LOW AT ABOUT 2000 FT AGL...AND LOW LEVEL COLD ADVECTION PERSISTING THROUGH THE DAY...TEMPS WILL HAVE TROUBLE MOVING OFF OF MORNING LOWS. INDEED...WILL LIKELY SEE TEMPS FALL THROUGH ABOUT MID-MORNING BEFORE SOME SLIGHT RECOVERY LATER IN THE DAY. HOWEVER...MAIN FOCUS CONTINUES TO BE ON CHANCE FOR VERY LIGHT PRECIPITATION TODAY AND TONIGHT AND POTENTIAL IMPACTS OF IT WITH TEMPS IN THE TEENS AND 20S. THIS PRECIP EVENT CONTINUES TO LOOK PRIMARILY ISENTROPIC DRIVEN WITH SOME MINOR CONTRIBUTION FROM FRONTOGENETICAL FORCING EARLY ON. ISENTROPIC PROJECTIONS DEPICT LIFT INITIALLY AT THE VERY TOP OF THE COLD AIR...PRIMARILY IN THE WARMER AND DRIER MID LEVELS ABOVE IT. HOWEVER...AS THE COLD AIR DEEPENS THROUGH THE DAY...SOME OF THIS COLD MOISTURE SHOULD BE TAPPED BY THE ISENTROPIC LIFT TO PRODUCE SOME LIGHT PRECIP. BEST WINDOW FOR THIS APPEARS TO BE BETWEEN 3 PM AND MIDNIGHT...AFTER WHICH ISENTROPIC LIFT WEAKENS SIGNIFICANTLY. QUESTION THEN BECOMES PHASE OF THIS PRECIPITATION. PROGGED SOUNDINGS SUPPORT EITHER FREEZING DRIZZLE OR VERY LIGHT SNOW. COLDER LOW LEVELS ACROSS THE NORTH AND WEST MIGHT END UP FAVORING FLURRIES TO A DUSTING OF SNOW WHILE FURTHER SOUTH AND EAST FREEZING DRIZZLE LIKELY TO BE PREDOMINANT. HOW MUCH IS A BIG QUESTION WITH SOUNDINGS SUGGESTING THE MODEL QPF OUTPUT IS OVERDONE. AS FOR POTENTIAL FOR ADVISORY...STILL SOME DETAILS TO WORK OUT SUCH AS FLURRIES VS DRIZZLE AND TIMING OF ONSET OF PRECIP HEAVY AND/OR WIDESPREAD ENOUGH TO BEGIN TO CAUSE TRAVEL ISSUES. SINCE CURRENT EXPECTATION IS THE MORE SIGNIFICANT PART OF THE EVENT IS STILL 8-12 HOURS AWAY AND ANOTHER MODEL RUN AND 12Z UA ANALYSIS SHOULD HELP NARROW DOWN THE DETAILS FURTHER...WILL DEFER ON THE ISSUANCE OF AN ADVISORY ATTM. LONG TERM... AN UA DISTURBANCE ACROSS THE GREAT BASIN IS STILL PROGGED TO PINCH OFF AND DIVE SSE TO ACROSS SRN CALI TOMORROW...AND ACROSS THE DESERT SW ON THURSDAY. AS SUCH...FLOW ALOFT WILL EVOLVE FROM A BROAD CYCLONIC FLOW TO SWRLY FLOW. IF THE ANTICIPATED TRACK OF THE SYSTEM DOES NOT CHANGE...IT WILL MOVE DIRECTLY ACROSS THE SOUTHERN PLAINS FRIDAY NIGHT THEN EXIT TO THE NE BY SATURDAY. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL. TEMPS STRUGGLING TO GET OUT OF THE 20S WILL CHARACTERIZE WEDNESDAY AS THE CAA USHERED IN BY LAST NIGHT/S COLD FRONTAL PASSAGE REMAINS ENTRENCHED. FURTHERMORE...MAY ALSO EXPERIENCE A LINGERING FREEZING DRIZZLE/WINTRY MIX...COURTESY OF MOISTENED ATMOSPHERIC LOW LEVELS AND AN UPSLOPE SFC REGIME. THIS WINTRY MIX MAY BE HARD-PRESSED TO REACH THE GROUND AS IT WILL HAVE TO FALL THROUGH RATHER DRY MID-LEVELS...WHICH IS WHERE THE SLIVER OF UL SUPPORT IS MAXIMIZED. ON THURSDAY DURING THE DAY...A SIMILAR SCENARIO TO WEDNESDAY WILL PLAY OUT...WITH THE DIFFERENCE BEING PROGGED MODEL SOUNDINGS HINTING AT A WARM TONGUE DEVELOPING IN THE MID-LEVELS...THUS SUGGESTING MORE OF A FREEZING RAIN/WINTRY MIX OCCURRENCE. NONETHELESS...THE BEST LIFT IS STILL MAXIMIZED WITHIN THE DRY MID-LEVELS AND HENCE LIGHT PRECIP IS EXPECTED. BY THURSDAY NIGHT HOWEVER...MID-LEVELS ARE SHOWN TO MOISTEN AS THE UA SYSTEM DRAWS NEAR. THE BEST UL SUPPORT IS FINALLY TAPPING INTO ADEQUATE MOISTURE. MID-LEVEL MOISTENING OCCURRING WITHIN THE DENDRITIC ZONE COULD PROMOTE A CHANCE OF SNOW...PARTICULARLY ACROSS THE HIGHER TERRAIN OF THE NWRN ZONES. ELSEWHERE...FREEZING RAIN AND PERHAPS SLEET WILL BE COMMON...WITH THE EXCEPTION OF THE FAR ROLLING PLAINS WHERE A MIX OF A COLD RAIN AND FREEZING RAIN MAY OCCUR...GIVEN TEMPS WILL WARM TO SLIGHTLY ABOVE FREEZING THERE /LOWER 30S ELSEWHERE/. TEMPS WILL WARMUP FURTHER ON FRIDAY...INTO THE MIDDLE TO UPPER 30S ON THE CAPROCK TO UPPER 30S TO LOWER 40S OFF THE CAPROCK...WHICH WILL AFFECT THE PRECIP PHASE. COULD THEREFORE SEE MORE OF A RAIN AND SNOW MIX OR A RAIN AND FREEZING RAIN MIX DEVELOP BY THE EVENING /THE NWRN ZONES WILL BE THE EXCEPTION AS SOUNDING PROFILES SUGGEST LIGHT SNOW THERE/. LATE FRIDAY NIGHT-EARLY SATURDAY MORNING...LARGE SCALE ASCENT WILL BE FLEETING AS THE SYSTEM COMMENCE TO EXIT THE REGION. PERHAPS SOME LINGERING RAIN AND SNOW MIX WILL BE POSSIBLE ACROSS PORTIONS OF THE ROLLING PLAINS EARLY SATURDAY MORNING. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL AND THE RETURN TO SRLY SFC FLOW EARLY NEXT WEEK WILL AID IN PUSHING TEMPS BACK UP TO NEAR 50. NOTE: ALTHOUGH THE WINTRY PRECIP IS EXPECTED TO BE LIGHT THIS WEEK...IT COULD STILL POSE A THREAT FOR HAZARDOUS ROAD CONDITIONS AS A THIN GLAZE OF ICE COULD FORM ACROSS OVERPASSES AND BRIDGES IN PARTICULAR. AS YOU HEAD OUT TO ENJOY THE NEW YEAR FESTIVITIES...CAUTION IS ADVISED. CHECK BACK TO STAY ALERT AND UP TO DATE WITH ANY WEATHER CHANGES. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 7 22 17 32 20 / 40 20 10 20 20 TULIA 10 22 19 32 23 / 40 10 10 20 20 PLAINVIEW 12 23 19 32 25 / 40 10 10 20 20 LEVELLAND 14 24 19 32 25 / 50 20 20 20 30 LUBBOCK 14 25 21 32 26 / 50 20 20 20 30 DENVER CITY 16 25 20 33 26 / 50 20 20 30 30 BROWNFIELD 15 25 20 33 26 / 50 20 20 30 30 CHILDRESS 14 25 22 34 26 / 40 10 10 20 30 SPUR 15 25 22 33 27 / 50 20 20 30 30 ASPERMONT 18 27 24 36 29 / 40 20 20 30 30 && .LUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ021>024-027>030-033>037-039>044. WIND CHILL ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ021>023. && $$ 05/99/05
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1006 AM CST TUE DEC 30 2014 .UPDATE... WITH FOG BEGINNING TO LIFT IN MANY AREAS EAST OF THE I35 CORRIDOR...ALLOWED THE DENSE FOG ADVISORY TO EXPIRE OUT THERE. HOWEVER...FOG IS SLUGGISH TO LIFT ON THE ESCARPMENT AND SOME LOCATIONS IN THE EASTERN PARTS OF THE I35 CORRIDOR COUNTIES ARE STILL SEEING VISIBILITIES RISE AND FALL. EXPECT THIS TO IMPROVE OVER THE NEXT TWO HOURS SO EXTENDED THE DFA THROUGH 18Z TO BE SAFE. TB3 && .PREV DISCUSSION... /ISSUED 725 AM CST TUE DEC 30 2014/ UPDATE...ONE FINAL UPDATE TO EXPAND DENSE FOG ADVISORY WEST TO THE RIO GRANDE. PREV DISCUSSION... /ISSUED 613 AM CST TUE DEC 30 2014/ AVIATION... LIFR/VLIFR VIS AND CIGS IN AUSTIN AND SAN ANTONIO THIS MORNING WILL CONTINUE UNTIL MID-MORNING WHEN NORTHWESTERLY WINDS PICK UP. THEN MVFR/IFR CIGS THROUGH THE REST OF THE TAF PERIOD. DRT WILL DROP TO IFR SHORTLY AND STAY THAT WAY UNTIL AROUND 18Z. EXPECTING PRECIPITATION WEDNESDAY MORNING AT DRT. HAVE NOT INCLUDED ANY PRECIP IN AUSTIN OR SAN ANTONIO...BUT THERE IS A SLIGHT CHANCE FOR RAIN. IF THERE IS ANY RAIN IT WILL DROP VIS TO MVFR. PREV DISCUSSION... /ISSUED 523 AM CST TUE DEC 30 2014/ UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIAMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLEY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING COUNTIES: BANDERA...BEXAR...BLANCO...BURNET...COMAL...EDWARDS...GILLESPIE... HAYS...KENDALL...KERR...KINNEY...LLANO...MAVERICK...MEDINA...REAL... TRAVIS...UVALDE...VAL VERDE...WILLIAMSON...ZAVALA. WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. && $$ MESOSCALE/AVIATION...03 SYNOPTIC/GRIDS...12 PUBLIC SERVICE/DATA COLLECTION...00