Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/18/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
914 PM MST SUN FEB 15 2015
.SYNOPSIS...EXPECT ISOLATED TO SCATTERED SHOWERS THROUGH MONDAY
EVENING. THE BEST CHANCE FOR HEAVIER RAINFALL WILL BE SOUTH OF
TUCSON. DRY CONDITIONS WITH WELL ABOVE NORMAL DAYTIME TEMPERATURES
WILL THEN OCCUR TUESDAY INTO NEXT WEEKEND.
&&
.DISCUSSION...EARLIER THIS EVENING SHOWERS ALONG WITH A FEW
THUNDERSTORMS DEVELOPED MOSTLY OVER SANTA CRUZ COUNTY WITH A COUPLE
OF RAIN GAUGES ALONG THE IMMEDIATE BORDER WITH MEXICO THAT INDICATED
AMOUNTS BETWEEN 0.70-0.90 INCHES. AS A RESULT...A SMALL STREAM FLOOD
ADVISORY WAS ISSUED FOR EXTREME SOUTHERN SANTA CRUZ COUNTY FROM
AROUND RUBY THROUGH NOGALES TO THE BORDER WITH COCHISE COUNTY. THE
ADVISORY HAS LONG SINCE EXPIRED AT 7 PM MST WITH RECENT RADAR MOSAIC
INDICATING THAT THE SHOWERS HAVE BEEN STEADILY DIMINISHING DURING
THE PAST HOUR AND A HALF AS THEY MOVE SLOWLY TO THE SOUTH WITH THE
INFLUENCE OF THE APPROACHING UPSTREAM SHORTWAVE FROM THE FOUR
CORNERS AREA. AS THIS FEATURE CONTINUES TO MOVE SOUTH IT WILL PUSH
THE BAJA LOW FARTHER SOUTH THROUGH THE DAY ON MONDAY.
IR SATELLITE IMAGERY SHOWS EXTENSIVE CLOUDINESS ASSOCIATED WITH THE
LOW PRESSURE SYSTEM THAT IS CURRENTLY SPINNING OVER THE CENTRAL GULF
OF CALIFORNIA...COVERING A LARGE PART OF NORTHERN MEXICO...SOUTHEAST
ARIZONA AND EASTWARD ACROSS MUCH OF NEW MEXICO AND WEST TEXAS.
LIGHTNING ACTIVITY ASSOCIATED WITH THE LOW HAS BEEN DECREASING FOR
THE PAST COUPLE OF HOURS...WITH MOST OF THE LIGHTNING STRIKES WELL
TO OUR SOUTH NEAR HERMOSILLO, MEXICO. LATEST HRRR AND U OF A WRF/NAM
ARE BOTH INDICATING THAT THE SHOWERS WILL CONTINUE TO MOVE FARTHER
SOUTH INTO MEXICO OVERNIGHT. WILL MAKE SOME MINOR TWEAKS TO THE POP
GRIDS TO REFLECT THIS NOTION...BUT WILL STILL MAINTAIN A SMALL
THREAT ALONG THE MEXICAN BORDER FROM AROUND THE NOGALES AREA TO THE
BORDER WITH NEW MEXICO.
AS OF 04Z (9 PM MST)...TEMPERATURES ACROSS THE REGION RANGED FROM
THE LOWER 50S TO THE LOWER 60S WITH THE TUCSON INTL AIRPORT
REPORTING A TEMP OF 62 DEGS AFTER AN AFTERNOON HIGH OF 71 DEGS...
WHICH WAS 3 DEGS ABOVE NORMAL FOR THIS DATE. INHERITED OVERNIGHT LOW
TEMPS SEEM TO BE ON TRACK...BUT WILL MAKE SOME ADJUSTMENTS TO THE
SHORT TERM HOURLY TEMP GRIDS TO REFLECT RECENT TRENDS.
FOR DETAILS REGARDING THE FORECAST BEYOND TONIGHT...PLEASE REFER TO
THE PREVIOUS DISCUSSION BELOW.
&&
.AVIATION...VALID THRU 17/06Z.
ISOLATED TO SCATTERED SHOWERS WILL OCCUR INTO MONDAY AFTERNOON.
THERE IS ALSO A SLIGHT CHANCE OF -TSRA SOUTH TO SOUTHEAST OF KTUS
MAINLY MONDAY AFTERNOON. OTHERWISE...CLOUD DECKS WILL GENERALLY
RANGE FROM 6K-12K FT AGL. SURFACE WIND EAST OF KTUS EARLY THIS
EVENING AND MONDAY AFTERNOON WILL BE WLY/NWLY AT 12-22 KTS WITH
GUSTS OF 25-30 KTS. THE STRONGEST WIND WILL OCCUR NE OF KTUS AND
ESPECIALLY IN THE VICINITY OF KSAD. ELSEWHERE...SURFACE WIND WILL
MAINLY BE LESS THAN 10 KTS THRU THE PERIOD. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT ISOLATED TO SCATTERED SHOWERS THROUGH MONDAY
EVENING. THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS MAINLY
MONDAY AFTERNOON AND EVENING...SOUTH TO SOUTHEAST OF TUCSON. DRY
CONDITIONS WILL THEN PREVAIL TUESDAY INTO NEXT WEEKEND. GUSTY WEST
TO NORTHWEST WINDS WILL OCCUR MONDAY AFTERNOON ESPECIALLY EAST OF
TUCSON. THEREAFTER...EXPECT GENERALLY LIGHT TERRAIN DRIVEN WINDS
DURING MUCH OF THE REST OF THE WEEK.
&&
.PREV DISCUSSION...THE UPPER LOW WILL MOVE EWD INTO THE CENTRAL GULF
OF CALIFORNIA TONIGHT...THEN WEAKEN RAPIDLY OVER SONORA MEXICO MON.
THE BEST CHANCE FOR ANY RAINFALL OF SIGNIFICANCE WILL OCCUR THROUGH
MON MORNING...THEN THE CHANCE OF ANY RAINFALL OF CONSEQUENCE WILL
DECREASE CONSIDERABLY BY MON EVENING.
THUS...THE OFFICIAL FORECAST CONTINUES WITH ISOLATED TO SCATTERED
SHOWERS INTO MON MORNING. THE BEST CHANCE OF HEAVIER RAINFALL WILL
OCCUR SOUTH-TO-SOUTHEAST OF TUCSON. ISOLATED TO PERHAPS SCATTERED
SHOWERS ARE EXPECTED MON AFTERNOON ACROSS SANTA CRUZ/COCHISE
COUNTIES. THERE APPEARS TO BE ENOUGH PROGGED INSTABILITY TO JUSTIFY
THE CONTINUATION OF A SLIGHT CHANCE OF THUNDERSTORMS MON AFTERNOON
MAINLY SE OF TUCSON. DRY CONDITIONS ARE FORECAST TO OCCUR ELSEWHERE
MON AFTERNOON.
A FEW LINGERING SHOWERS MAY OCCUR MON EVENING MAINLY ACROSS COCHISE
COUNTY. HAVE NOTED THAT THE 15/12Z ECMWF REMAINED CONSISTENT WITH
DEPICTING LIGHT QPF/S TO OCCUR MAINLY ACROSS THE WHITE MOUNTAINS MON
NIGHT. HOWEVER...THE 15/12Z NAM/GFS/CMC DEPICTED PRECIP-FREE
CONDITIONS TO OCCUR ACROSS THE AREA. ALTHOUGH THERE WILL BE AN
IMPULSE EMBEDDED WITHIN NWLY FLOW ALOFT THAT WILL MOVE SEWD ACROSS
ERN SECTIONS...THE ECMWF SOLUTION WAS DISCOUNTED GIVEN THE VERY DRY
REGIME UPSTREAM FROM THE AREA.
THEREAFTER...A HIGHLY AMPLIFIED PATTERN TUE WITH A STRONG HIGH
PRESSURE RIDGE ADJACENT THE WEST COAST AND DEEP TROUGH OVER THE ERN
CONUS IS PROGGED TO TRANSITION TOWARD A BROAD TROUGH OVER THE
ROCKIES AND CENTRAL CONUS BY NEXT WEEKEND. AT THIS TIME APPEARS THAT
ANY MEASURABLE PRECIP NEXT WEEKEND WILL BE NORTH AND EAST OF THIS
FORECAST AREA. HOWEVER...FORECAST CONFIDENCE IS SOMEWHAT LOW
REGARDING THIS SCENARIO...ESPECIALLY GIVEN THE RUN-TO-RUN
DIFFERENCES BETWEEN GFS/ECMWF SOLUTIONS. AT ANY RATE...HAVE OPTED
FOR PRECIP-FREE CONDITIONS DURING THE LATTER PART OF THE FORECAST
PERIOD.
HIGH TEMPS INTO NEXT WEEKEND WILL MOSTLY AVERAGE NEARLY 5-10 DEGS F
ABOVE NORMAL. THE WARMEST DAYS FOR MOST LOCALES WILL BE THUR-FRI.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
CURRENT DISCUSSION...MOLLERE
PREVIOUS DISCUSSION...FRANCIS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
940 PM MST SUN FEB 15 2015
.UPDATE...
ISSUED AT 456 PM MST SUN FEB 15 2015
TRAVEL IMPACTS ALONG INTERSTATE 70 NEAR VAIL PASS CONTINUE LATE
THIS AFTERNOON AND SPOTTERS REPORTING MODERATE TO HEAVY SNOW STILL
FALLING AND SLOW TRAVEL. HAVE ADJUST POP GRIDS SLIGHTLY IN THIS
AREA TO FIT CURRENT TRENDS. EXPECT A LULL IN ACTIVITY AFTER 1900
THIS EVENING...WITH SNOW PICKING BACK UP AFTER 3 AM BASED ON
LATEST HRRR GUIDANCE.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MST SUN FEB 15 2015
A COLD FRONT MOVING SOUTHWARD AHEAD OF AN UPPER LEVEL SHORT WAVE
TROUGH WAS POSITIONED ALONG A KBCE-KAIB-KMTJ-KLXV LINE AT 2 PM
MST. WINDS HAD SHIFTED TO THE NORTHWEST AND INCREASED TO 15 TO 20
MPH WITH GUSTS TO 30 MPH AT A NUMBER OF LOCATIONS IN THE WAKE OF
THE FRONT. ALSO BEHIND THE FRONT...LIGHT PRECIPITATION HAD STARTED
WHICH WAS EXPECTED. KEEO REPORTED MIXED PHASE PRECIPITATION WHICH
BEGAN AS LIGHT RAIN AND CHANGED OVER TO SNOW. MEANWHILE...WEB CAMS
INDICATED LIGHT SNOW IN THE PARK RANGE ABOVE KSBS AS DID CAMS FROM
VAIL PASS AND THE VAIL SKI AREAS. SNOW WILL CONTINUE IN THE
NORTHERN AND CENTRAL MOUNTAINS DURING THE REMAINDER OF THE
AFTERNOON AS THE SHORTWAVE TROUGH MOVES OVERHEAD. ADDITIONAL LIFT
PROVIDED BY JET LEVEL DIVERGENCE AND OROGRAPHIC LIFT.
THOUGH THE SHORTWAVE TROUGH AXIS MOVES EAST OF THE DIVIDE THIS
EVENING...LATEST MODELS INDICATED THAT LIGHT TO MODERATE SNOWFALL
WILL CONTINUE OVER THE NORTHERN AND CENTRAL DIVIDE MOUNTAINS
THROUGH THE NIGHT DUE TO OROGRAPHIC LIFT IN AN ENVIRONMENT
FEATURING STEEP LAPSE RATES OF 7.5 TO 8.0 DEG/KM. SNOW INCREASES
IN COVERAGE AND INTENSITY ON MONDAY AS ANOTHER SHORTWAVE TROUGH
MOVES ACROSS THE AREA FROM THE NORTHWEST. THE LEFT EXIT REGION OF
A 135 KT JET MOVES OVERHEAD EARLY IN THE DAY TO ENHANCE LIFT. THE
BULK OF THE MOISTURE REMAINS OVER THE NORTHERN AND CENTRAL
COLORADO MOUNTAINS...THOUGH SOME SNOW WILL MOVE INTO THE WESTERN
SAN JUANS DURING THE AFTERNOON.
SINCE MODELS WERE MORE PERSISTENT WITH THE SNOWFALL THROUGH THE
NEXT 24 HOURS ACCUMULATIONS ARE EXPECTED TO REACH ADVISORY LEVELS
ACROSS THE ELKHEAD...PARK AND GORE RANGES AS WELL AS PORTIONS OF
THE ELK RANGE. NAM INDICATED AS MUCH AS 12 INCHES IN THE HIGHER
MOUNTAINS WHILE GFS AND ECMWF WERE A BIT MORE UNDERSTATED. GIVEN
GUIDANCE OUTPUT WENT AHEAD WITH STORM TOTALS OF 6 TO 12 INCHES IN
THESE AREAS.
SNOW DECREASES AND BECOMES MORE SCATTERED IN COVERAGE MONDAY NIGHT
AS THE SECOND WAVE SHIFTS EAST OF THE AREA. CLOUDS AND
PRECIPITATION WILL MODERATE TEMPERATURES TONIGHT WITH MOST
LOCATIONS ABOVE NORMAL. CONVERSELY...HIGHS WILL BE COOLER DUE TO
THE INFLUX OF COOLER AIR AND CLOUD COVER. DECREASING CLOUDS
MONDAY NIGHT WILL LEAD TO BELOW NORMAL LOWS BY TUESDAY MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MST SUN FEB 15 2015
A NORTH-NORTHWEST FLOW WILL PREVAIL OVER THE FORECAST AREA ON
TUE...THEN WILL WEAKEN SOMEWHAT ON WEDNESDAY. A WEAK DISTURBANCE
EMBEDDED IN THE FLOW WILL DROP INTO THE NORTHERN PLAINS ON
TUE...ON THE BACKSIDE OF THE LARGE LOW PRESSURE TROUGH ACROSS THE
NATION`S MID SECTION TO THE EAST COAST. THIS WILL BRUSH OUR
NORTHEAST CORNER...AND ALONG WITH NORTHWEST OROGRAPHICS WILL KEEP
A CHANCE OF SNOW ALONG THE NORTHERN DIVIDE MOUNTAINS INTO THE
AFTERNOON. BY EARLY EVENING ANY LINGERING SHOWERS WILL END AS THE
GRADIENT BEGINS TO RELAX...AND MOISTURE DIMINISHES. THEN ON WED
ANOTHER EMBEDDED WAVE WILL PASS TO OUR NORTHEAST. THIS ONE WILL
HAVE LESS EFFECT ON OUR AREA AS IT WILL BE FARTHER AWAY AS HIGH
PRESSURE BUILDS OVER THE WEST COAST. THEREFORE DO NOT EXPECT MUCH
MORE THAN INCREASED CLOUDS FOR A TIME OVER MAINLY OVER THE
NORTHEAST CORNER.
HIGH PRESSURE WILL PERSIST OVER THE WEST COAST THROUGH THE END OF
THE LONG TERM PERIOD AND BEYOND. ON THU AND FRI...A MORE RELAXED
NORTHWEST FLOW OVER OUR AREA AND WARMING TEMPERATURES ALOFT WILL
ALLOW SURFACE TEMPERATURES TO REBOUND. THEN BY LATE FRIDAY THE FLOW
WILL BECOME WESTERLY AS A DEVELOPING SHORTWAVE TROUGH APPROACHES
FROM THE NORTH. THIS TROUGH WILL BRING OUR NEXT CHANCE WINTRY
CONDITIONS TO THE AREA THIS WEEKEND. HOWEVER THERE CONTINUES TO
BE SIGNIFICANT DIFFERENCES IN THE MODELS. SO CONFIDENCE IS NOT
HIGH. STAY TUNED TO FUTURE FORECASTS AS THIS STORM SYSTEM EVOLVES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 940 PM MST SUN FEB 15 2015
THE MAIN PIECE OF THIS STORM SYSTEM HAS PASSED EAST OF THE DIVIDE
THIS EVENING WITH A SHORT WINDOW OF IMPROVED VFR CONDITIONS AT ALL
OF THE TERMINAL SITES. HOWEVER A SECONDARY PIECE OF ENERGY WILL
BRING ANOTHER ROUND OF MOUNTAIN SNOW SHOWERS MAINLY AFTER 12Z
MONDAY. THIS PIECE OF THE STORM IS WEAKER BUT WITH COLD AIR IN
PLACE SNOW WILL BE EASIER TO PRODUCE. THEREFORE PERIODS OF MVFR TO
LOCAL IFR CONDITIONS WILL BE FORECAST FOR KASE AND KEGE. KRIL AND
KTEX WILL BE THE FRINGE OF THE LOWER CLOUDS AND WIDESPREAD SHOWERS
BUT LOWER FLIGHT CRITERIA COULD TEMPORARILY IMPACT THESE STATIONS
AS WELL AFTER 14Z TODAY. IMPROVING CONDITIONS AFTER SUNSET ON
MONDAY CAN BE EXPECTED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 PM MST MONDAY FOR COZ004-010.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...NL
LONG TERM...EH
AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
930 PM EST TUE FEB 17 2015
.UPDATE...
SHIELD OF LIGHT RAIN WILL CONTINUE TO BREAK UP AND SHIFT
SOUTHEAST THROUGH MIDNIGHT. ADDITIONAL RAINFALL AMOUNTS WILL BE
VERY LIGHT...MAINLY AVERAGING JUST A FEW HUNDREDTHS OR LESS.
LAST OF THE LIGHT RAIN SHOWERS WILL MOVE SOUTH OF THE AREA DURING
THE PRE-DAWN HOURS. COOLER DRIER AIR WILL FILTER IN FROM THE
NORTHWEST AND SKIES WILL BEGIN TO CLEAR FROM THE NORTHWEST AFTER
MIDNIGHT. LOW TEMPS WILL NEAR THE FREEZING MARK ACROSS INTERIOR SE
GA WITH LOWS ACROSS NE FL RANGING FROM THE MID TO UPPER 30S ALONG
THE I-10 CORRIDOR TO THE LOW TO MID 50S SOUTH OF A LINE FROM
GAINESVILLE TO ST AUGUSTINE.
TOMORROW WILL BE A MOSTLY SUNNY BUT COOL AND WINDY DAY WITH WIND
GUSTS EXCEEDING 30 MPH AT TIMES DURING THE AFTERNOON AS THE
PRESSURE GRADIENT TIGHTENS ALONG AND BEHIND A SECONDARY COLD
FRONT. A WIND ADVISORY IS LOOKING LIKELY FOR AT LEAST PORTIONS OF
THE REGION...NAMELY SOUTHEAST GEORGIA. STRONG COLD AIR ADVECTION
WILL GET UNDERWAY LATE TOMORROW.
&&
.AVIATION...CONSIDERABLE UNCERTAINTY AS TO HOW LONG THE LOWER CIGS
WILL LAST OVER THE AREA. LATEST HRRR GUIDANCE KEEPS LOW MVFR
CIGS OVER TAF SITES THRU ABOUT 08Z...THEN CLEARING THRU 10Z...WITH
VFR THEREAFTER. LATEST TAFS FOLLOW THIS TREND. NW WINDS 5-10KTS
TONIGHT...THEN 10-15KTS WITH OCCASIONAL GUSTS TO 20KTS WED.
&&
.MARINE...
NORTH WINDS WILL BACK TO THE NORTHWEST AND INCREASE AFTER
MIDNIGHT. WILL RETAIN CAUTION STATEMENT FOR THE OFFSHORE SEGMENTS
OVERNIGHT. WINDS WILL BACK TO THE WEST AND INCREASE EVEN MORE ON
WEDNESDAY...REACHING SMALL CRAFT ADVISORY CRITERIA TUESDAY
AFTERNOON.
RIP CURRENTS: LOW RISK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 33 54 25 43 / 40 0 0 0
SSI 38 55 27 45 / 80 0 0 0
JAX 38 57 28 47 / 90 0 0 0
SGJ 43 58 31 47 / 90 0 0 0
GNV 39 58 28 51 / 90 0 0 0
OCF 42 59 30 52 / 90 0 0 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...HARD FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR BAKER-COASTAL NASSAU-COLUMBIA-HAMILTON-INLAND
NASSAU-SUWANNEE.
FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING
FOR ALACHUA-BRADFORD-CLAY-COASTAL DUVAL-FLAGLER-GILCHRIST-
INLAND DUVAL-MARION-PUTNAM-ST. JOHNS-UNION.
GA...HARD FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-
COASTAL CAMDEN-COASTAL GLYNN-COFFEE-ECHOLS-INLAND CAMDEN-
INLAND GLYNN-JEFF DAVIS-PIERCE-WARE-WAYNE.
AM...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 6 PM EST THURSDAY
FOR WATERS FROM ALTAMAHA SOUND GA TO FERNANDINA BEACH FL
FROM 20 TO 60 NM-WATERS FROM FERNANDINA BEACH TO ST.
AUGUSTINE FL FROM 20 TO 60 NM-WATERS FROM ST. AUGUSTINE TO
FLAGLER BEACH FL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY FOR WINDS FROM NOON WEDNESDAY TO NOON EST
THURSDAY FOR COASTAL WATERS FROM ALTAMAHA SOUND TO
FERNANDINA BEACH FL OUT 20 NM-COASTAL WATERS FROM
FERNANDINA BEACH TO ST. AUGUSTINE FL OUT 20 NM-COASTAL
WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM.
&&
$$
SHULER/WOLF/
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
249 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL BE NEAR THE FORECAST AREA TONIGHT AND OFF THE
COAST TUESDAY. WINTER-TYPE PRECIPITATION WILL OCCUR ACROSS THE
NORTHERN PORTIONS OF SC BECAUSE OF THE COLDER AIR MASS IN PLACE
AHEAD OF THE SYSTEM. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD UPPER LEVEL TROUGH IN THE MIDWEST WILL CONTINUE SHIFTING
EAST WITH SOUTHWESTERLY FLOW INCREASING ACROSS THE CAROLINAS. 19Z
SURFACE ANALYSIS SHOWS HIGH PRESSURE ALONG THE NC/VA COAST RIDGING
INTO THE FORECAST AREA. MEANWHILE...LOW PRESSURE OVER THE TN/MS
VALLEY REGION IS SHIFTING NORTHEAST TOWARD THE REGION ACCOMPANIED
BY A LARGE SWATH OF PRECIPITATION. REGIONAL RADAR COMPOSITE THIS
AFTERNOON SHOWS LIGHT PRECIPITATION BEGINNING TO MOVE INTO THE
WESTERN MIDLANDS AND CSRA WHICH IS SUPPORTED BY WARM ADVECTION AND
ISENTROPIC LIFT AHEAD OF THE LOW. WE HAVE RECEIVED A FEW REPORTS
OF LIGHT SLEET IN NEWBERRY COUNTY. DRY AIR MASS IS MOISTENING FROM
THE SOUTH THIS AFTERNOON WITH DEWPOINTS ON THE RISE. DEWPOINTS IN
THE PEE DEE AND NORTHERN MIDLANDS REMAIN VERY DRY...GENERALLY IN
THE SINGLE DIGITS.
LATEST MODEL GUIDANCE STILL SUPPORTS LOW TRACK ACROSS THE WESTERN
PART OF THE FORECAST AREA TONIGHT. HRRR APPEARS TO BE TRACKING
WELL WITH CURRENT RADAR TRENDS AND IS MUCH FASTER WITH THE PRECIP
REACHING THE AREA THAN THE 12Z NAM. THIS AGREES PRETTY WELL WITH
TIMING IN CURRENT FORECAST SO HAVE NOT MADE ANY TIMING
ADJUSTMENTS. HIGH RESOLUTION MODELS LIKE THE RAP AND HRRR ARE
WARMER THAN SOME OF THE OTHER GUIDANCE BUT BELIEVE THIS MAY BE
A LITTLE OVERDONE AS THESE MODELS HAVE BEEN TOO HIGH WITH THE
DEWPOINTS SO FAR TODAY. PRECIPITABLE WATER INCREASES TO NEAR 1.3
INCHES BY 06Z TUESDAY AND ISENTROPIC LIFT IS ALSO VERY STRONG
DURING THIS TIME SO HAVE HIGHEST POPS 03Z TO 09Z. MODEL SOUNDINGS
INDICATE DEEP WARM NOSE ACROSS THE REGION TONIGHT AS VERY STRONG
LOW LEVEL WARM ADVECTION DEVELOPS. SOUTHWEST 850MB JETMAX GREATER
THAN 60KTS. SHALLOW FREEZING LAYER LIKELY NORTH OF CAE. LARGE
TEMPERATURE GRADIENT EXPECTED WITH FREEZING TEMPS NORTH OF CAE
TONIGHT TO POSSIBLY LOW 50S IN THE CSRA AS WARM ADVECTION
INCREASES AND DEEPENS. TEMPERATURES EXPECTED TO RISE OVERNIGHT IN
THE SOUTHERN AREAS.
WITH DEEP WARM NOSE AND SHALLOW FREEZING LAYER...STILL EXPECT
FREEZING RAIN IN THE NORTH MIDLANDS...PIEDMONT AND PEE DEE
OVERNIGHT. ICING ESTIMATE IN MOST AREAS LESS THAN A TENTH OF AN
INCH WITH THE HIGHEST AMOUNTS EXPECTED IN NORTHERN LANCASTER
COUNTY OF UP TO TWO TENTHS OF AN INCH. FREEZING RAIN ADVISORY
REMAINS IN EFFECT.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
BOTH THE NAM AND GFS SHOW THE CENTER OF THE LOW ALONG THE VA/NC
COAST BY 12Z TUESDAY MORNING WITH MOISTURE DECREASING ACROSS THE
AREA AS THE LOW CONTINUES TO SHIFT FURTHER NORTHEAST THROUGH THE
DAY ON TUESDAY. SHORTWAVE ENERGY ASSOCIATED WITH THE TROUGH WILL
PROMOTE A SLIGHT CHANCE OF LIGHT PRECIP TUESDAY MORNING AS IT
CROSSES THE REGION. MODEL SOUNDINGS SUGGEST MOISTURE BECOMING
QUITE SHALLOW EARLY TUESDAY...KEPT LOW CHANCE POPS AND
PRECIPITATION MAINLY LIQUID RAIN ALTHOUGH LIGHT FREEZING
RAIN/DRIZZLE POSSIBLE IN THE NORTH MIDLANDS THROUGH ABOUT 15Z.
MODELS CONTINUE TO HINT AT A SLIGHT CHANCE OF LIGHT SNOW TUESDAY
NIGHT AS THE UPPER TROUGH SHIFTS EAST...ALTHOUGH MOISTURE APPEARS
VERY LIMITED...SO HAVE KEPT POPS LOW FOR NOW. HIGHS ON TUESDAY ARE
FORECAST IN THE LOWER 40S NORTH TO LOWER 50S SOUTH. DECREASING
CLOUDS TUESDAY NIGHT WILL PROMOTE LOWS IN THE UPPER 20S NORTH TO
LOWER 30S SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
GENERALLY DRY INTO THE WEEKEND. HIGH PRESSURE WILL BUILD IN FROM THE
WEST WITH A REINFORCING SHOT OF ARCTIC AIR MOVING INTO THE AREA
THURSDAY AND FRIDAY. ANOTHER LOW PRESSURE SYSTEM DEVELOPING IN
THE SOUTHERN PLAINS BY EARLY SATURDAY WILL MOVE INTO THE TN VALLEY
BY SUNDAY AS MORE HIGH PRESSURE BUILDS IN FROM THE NORTH. AS A
RESULT...A COLD AIR DAMMING SCENARIO MAY OVER THE WEEKEND INTO
MONDAY. STILL LOTS OF QUESTIONS REGARDING TIMING AND PLACEMENT OF
THIS NEXT SYSTEM AND THE POSSIBILITY OF ANY WINTRY PRECIPITATION
EARLY NEXT WEEK. BUT WITH SOME MANY MODEL UNCERTAINTIES AT THIS
TIME...FOR NOW WILL KEEP PRECIPITATION ALL LIQUID SATURDAY INTO
MONDAY WITH CHANCE POPS. TEMPERATURES GENERALLY BELOW NORMAL THROUGH
THE EXTENDED PERIOD...WITH WELL BELOW NORMAL TEMPERATURES THURSDAY
AND FRIDAY. IN FACT...CURRENT MEX/MEN GUIDANCE HAS TEMPERATURES
ABOUT 20 TO 25 DEGREES BELOW NORMAL FOR CAE AND AGS THURSDAY AND
FRIDAY.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH EARLY EVENING THEN MVFR/IFR CONDITIONS FOR
THE REMAINDER OF THE PERIOD.
LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY WILL MOVE EAST
ACROSS THE GULF COAST STATES TODAY AND CROSS THE FORECAST AREA
OVERNIGHT. CLOUDS CONTINUE TO THICKEN AND LOWER THIS AFTERNOON AS
MOISTURE INCREASES AHEAD OF THE APPROACHING LOW. GENERALLY EAST
WINDS GRADUALLY SHIFTING SOUTHEAST INTO EARLY EVENING...THEN
TURNING SOUTHERLY AND INCREASING TO AROUND 15-20 MPH WITH SOME
STRONGER GUSTS AS LOW PRESSURE MOVES INTO THE STATE. DRY AIR IN
PLACE WILL HELP TO EVAPORATE PRECIPITATION AS IT MOVES IN LATE
AFTERNOON BUT LIGHT RAIN SHOULD REACH TERMINALS AFTER 22Z-23Z AND
BECOME MORE WIDESPREAD BY 02Z-03Z AT AGS/DNL/CAE/CUB AND 04Z-06Z
AT OGB. CIGS AND VSBYS WILL DROP TO MVFR AT THE ONSET AND THEN
CIGS FALL TO IFR FOR A PERIOD OF TIME AS THE LOW CROSSES THE AREA
AND WINDS SHIFT TO THE WEST AND NORTHWEST AFTER THE LOW PASSES BY.
FREEZING RAIN IS NOT EXPECTED AT THE TERMINALS. CONDITIONS SLOWLY
IMPROVE AFTER 12Z FROM WEST TO EAST BUT CIGS REMAIN RESTRICTED.
EXTENDED AVIATION OUTLOOK...MVFR...POSSIBLE IFR...RESTRICTIONS
COULD LINGER INTO TUESDAY NIGHT. BREEZY CONDITIONS EXPECTED
WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ015-016-
020>022.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1239 PM EST MON FEB 16 2015
.SYNOPSIS...
MOISTURE WILL INCREASE SLOWLY ACROSS THE REGION TODAY AHEAD OF
LOW PRESSURE TRACKING EASTWARD IN THE LOWER MISSISSIPPI RIVER
VALLEY. THE LOW WILL BE NEAR THE FORECAST AREA TONIGHT AND OFF
THE COAST TUESDAY. WINTER-TYPE PRECIPITATION WILL OCCUR ACROSS THE
NORTHERN PORTIONS OF SC BECAUSE OF THE COLDER AIR MASS IN PLACE
AHEAD OF THE SYSTEM. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD UPPER LEVEL TROUGH IN THE MIDWEST WILL SHIFT EAST WITH
RESULTING FLOW INCREASING FROM THE SOUTHWEST ACROSS THE CAROLINAS.
SURFACE HIGH PRESSURE RIDGING INTO THE AREA BEGINNING TO SHIFT TO
THE NORTHEAST AS LOW PRESSURE TRACKING FROM THE LOWER MISSISSIPPI
VALLEY APPROACHES THE REGION. AIR MASS REMAINS QUITE COLD AND DRY
WITH TEMPERATURES IN THE 30S LATE THIS MORNING AND DEW POINTS IN
THE SINGLE DIGITS IN MOST LOCATIONS. MODELS ARE CONTINUING TO
TREND FURTHER NORTH WITH APPROACHING SURFACE LOW PRESSURE. LATEST
MODELS IN GOOD AGREEMENT WITH SURFACE LOW TRACK ACROSS THE
CSRA/CENTRAL MIDLANDS TONIGHT TO OFF THE NORTH CAROLINA COAST
TUESDAY MORNING. LOW LEVEL WARM ADVECTION/ISENTROPIC LIFT WILL
DEVELOP LATER THIS AFTERNOON ACROSS THE REGION AS THE LOW PRESSURE
AREA APPROACHES. IN-SITU WEDGE LIKELY TO SET UP ACROSS THE
NORTHERN MIDLANDS AND PIEDMONT WITH SHALLOW SURFACE BASED COLD
LAYER. TEMPERATURES WILL STRUGGLE TO RISE THROUGH THE 30S IN THOSE
AREAS. AIR MASS INITIALLY DRY...SO PRECIPITATION MAY BE DELAYED
UNTIL EARLY EVENING. HRRR APPEARS TO BE TRACKING WELL WITH CURRENT
RADAR TRENDS AND IS MUCH FASTER WITH THE PRECIP REACHING THE AREA
THAN THE 12Z NAM. THIS AGREES PRETTY WELL WITH TIMING IN CURRENT
FORECAST SO HAVE NOT MADE ANY ADJUSTMENTS. PRECIPITABLE WATER
INCREASES TO NEAR 1.3 INCHES BY 06Z TUESDAY AND ISENTROPIC LIFT IS
STRONG DURING THIS TIME SO BELIEVE PRECIPITATION MAY BE MODERATE
AT TIMES. MODEL SOUNDINGS INDICATE DEEP WARM NOSE ACROSS THE
REGION TONIGHT AS VERY STRONG LOW LEVEL WARM ADVECTION DEVELOPS.
SOUTHWEST 850MB JETMAX GREATER THAN 60KTS. SHALLOW FREEZING LAYER
LIKELY HOWEVER NORTH OF CAE. LARGE TEMPERATURE GRADIENT EXPECTED
WITH FREEZING TEMPS NORTH OF CAE TONIGHT TO POSSIBLY LOW 50S IN
THE CSRA AS WARM ADVECTION INCREASES AND DEEPENS. TEMPERATURES
EXPECTED TO RISE OVERNIGHT IN THE SOUTHERN AREAS.
WITH DEEP WARM NOSE AND SHALLOW FREEZING LAYER...PRECIPITATION
TYPE MOST LIKELY TO BE FREEZING RAIN IN THE NORTH
MIDLANDS...PIEDMONT AND PEE DEE OVERNIGHT. ICING ESTIMATE UP TO
0.20 INCHES IN THE LANCASTER REGION SEEMS APPROPRIATE GIVEN
EXPECTED QPF. FREEZING RAIN ADVISORY REMAINS IN EFFECT. WINTRY
PRECIPITATION ACROSS THE REST OF THE CWA APPEARS UNLIKELY GIVEN
CURRENT LOW TRACK ACROSS THE SOUTH-CENTRAL MIDLANDS/CSRA.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
BOTH THE NAM AND GFS SHOW THE CENTER OF THE LOW ALONG THE VA/NC
COAST BY 12Z TUESDAY MORNING WITH MOISTURE DECREASING ACROSS THE
AREA AS THE LOW CONTINUES TO SHIFT FURTHER NORTHEAST THROUGH THE
DAY ON TUESDAY. SHORTWAVE ENERGY ASSOCIATED WITH THE TROUGH WILL
PROMOTE A SLIGHT CHANCE OF LIGHT PRECIP TUESDAY MORNING AS IT
CROSSES THE REGION. MODEL SOUNDINGS SUGGEST MOISTURE BECOMING
QUITE SHALLOW EARLY TUESDAY...KEPT LOW CHANCE POPS AND
PRECIPITATION MAINLY LIQUID RAIN ALTHOUGH LIGHT FREEZING
RAIN/DRIZZLE POSSIBLE IN THE NORTH MIDLANDS THROUGH ABOUT 15Z.
DRYING WILL OCCUR BY TUESDAY AFTERNOON. HIGHS ON TUESDAY ARE
FORECAST NEAR 40 NORTH TO THE LOW 50S SOUTH. DECREASING CLOUDS
TUESDAY NIGHT WILL PROMOTE LOWS IN THE UPPER 20S NORTH TO LOWER
30S SOUTH.
HIGHLY AMPLIFIED UPPER TROUGH OVER THE EASTERN CONUS WEDNESDAY
SUPPORTS BELOW NORMAL TEMPERATURES WITH SOME MID AND HIGH LEVEL
CLOUDS ASSOCIATED WITH SHORT WAVE TROUGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH FRIDAY NIGHT WITH INCREASING
DIFFERENCES SATURDAY THROUGH MONDAY. HIGHLY AMPLIFIED UPPER LEVEL
PATTERN THROUGH THE LONG TERM WILL KEEP AN UPPER LEVEL RIDGE OVER
THE WEST COAST WITH A TROUGH OVER THE EASTERN US. THIS WILL KEEP
AN ACTIVE PATTERN ACROSS THE FORECAST AREA WITH SYSTEMS EVERY
COUPLE OF DAYS. HIGH PRESSURE ALONG WITH COOLER AND DRIER AIR WILL
BUILD INTO THE REGION WEDNESDAY NIGHT WITH THE UPPER LEVEL TROUGH
AXIS JUST WEST OF THE REGION. THE HIGH WILL BE CENTERED JUST NORTH
OF THE REGION ON THURSDAY THEN EJECT NORTHEASTWARD ON FRIDAY AS
THE NEXT LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES REGION
WITH A SECONDARY LOW EXPECTED TO DEVELOP IN CENTRAL TX. MODELS
DIFFER ON THE HANDLING OF THE TX LOW...HOWEVER AGREE ON A FRONTAL
BOUNDARY ACROSS THE FORECAST AREA FOR FRIDAY NIGHT THROUGH MONDAY.
HAVE TRENDED MUCH OF THE LONG TERM TOWARD THE GFS AS RUN TO RUN
CONSISTENCY HAS BEEN BETTER THEN THE ECMWF WHICH HAS MADE
SIGNIFICANT RUN TO RUN CHANGES REGARDING THE TX LOW. TEMPERATURES
THROUGH THE LONG TERM WILL BE SLIGHTLY TO WELL BELOW NORMAL.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS THROUGH EARLY EVENING THEN MVFR/IFR CONDITIONS FOR
THE REMAINDER OF THE PERIOD.
LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY WILL MOVE EAST
ACROSS THE GULF COAST STATES TODAY AND CROSS THE FORECAST AREA
OVERNIGHT. CLOUDS CONTINUE TO THICKEN AND LOWER THIS AFTERNOON AS
MOISTURE INCREASES AHEAD OF THE APPROACHING LOW. GENERALLY EAST
WINDS GRADUALLY SHIFTING SOUTHEAST INTO EARLY EVENING...THEN
TURNING SOUTHERLY AND INCREASING TO AROUND 15-20 MPH WITH SOME
STRONGER GUSTS AS LOW PRESSURE MOVES INTO THE STATE. DRY AIR IN
PLACE WILL HELP TO EVAPORATE PRECIPITATION AS IT MOVES IN LATE
AFTERNOON BUT LIGHT RAIN SHOULD REACH TERMINALS AFTER 22Z-23Z AND
BECOME MORE WIDESPREAD BY 02Z-03Z AT AGS/DNL/CAE/CUB AND 04Z-06Z
AT OGB. CIGS AND VSBYS WILL DROP TO MVFR AT THE ONSET AND THEN
CIGS FALL TO IFR FOR A PERIOD OF TIME AS THE LOW CROSSES THE AREA
AND WINDS SHIFT TO THE WEST AND NORTHWEST AFTER THE LOW PASSES BY.
FREEZING RAIN IS NOT EXPECTED AT THE TERMINALS. CONDITIONS SLOWLY
IMPROVE AFTER 12Z FROM WEST TO EAST BUT CIGS REMAIN RESTRICTED.
EXTENDED AVIATION OUTLOOK...MVFR...POSSIBLE IFR...RESTRICTIONS
COULD LINGER INTO TUESDAY NIGHT. BREEZY CONDITIONS EXPECTED
WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ015-016-
020>022.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1059 AM EST MON FEB 16 2015
.SYNOPSIS...
MOISTURE WILL INCREASE SLOWLY ACROSS THE REGION TODAY AHEAD OF
LOW PRESSURE TRACKING EASTWARD IN THE LOWER MISSISSIPPI RIVER
VALLEY. THE LOW WILL BE NEAR THE FORECAST AREA TONIGHT AND OFF
THE COAST TUESDAY. WINTER-TYPE PRECIPITATION WILL OCCUR ACROSS THE
NORTHERN PORTIONS OF SC BECAUSE OF THE COLDER AIR MASS IN PLACE
AHEAD OF THE SYSTEM. WELL BELOW NORMAL TEMPERATURES EXPECTED
THROUGH THE WEEK UNDER THE INFLUENCE OF AN ARCTIC AIR MASS.
&&
.NEAR TERM /THROUGH TONIGHT/...
BROAD UPPER LEVEL TROUGH IN THE MIDWEST WILL SHIFT EAST WITH
RESULTING FLOW INCREASING FROM THE SOUTHWEST ACROSS THE CAROLINAS.
SURFACE HIGH PRESSURE RIDGING INTO THE AREA BEGINNING TO SHIFT TO
THE NORTHEAST AS LOW PRESSURE TRACKING FROM THE LOWER MISSISSIPPI
VALLEY APPROACHES THE REGION. AIR MASS REMAINS QUITE COLD AND DRY
WITH TEMPERATURES IN THE 30S LATE THIS MORNING AND DEW POINTS IN
THE SINGLE DIGITS IN MOST LOCATIONS. MODELS ARE CONTINUING TO
TREND FURTHER NORTH WITH APPROACHING SURFACE LOW PRESSURE. LATEST
MODELS IN GOOD AGREEMENT WITH SURFACE LOW TRACK ACROSS THE
CSRA/CENTRAL MIDLANDS TONIGHT TO OFF THE NORTH CAROLINA COAST
TUESDAY MORNING. LOW LEVEL WARM ADVECTION/ISENTROPIC LIFT WILL
DEVELOP LATER THIS AFTERNOON ACROSS THE REGION AS THE LOW PRESSURE
AREA APPROACHES. IN-SITU WEDGE LIKELY TO SET UP ACROSS THE
NORTHERN MIDLANDS AND PIEDMONT WITH SHALLOW SURFACE BASED COLD
LAYER. TEMPERATURES WILL STRUGGLE TO RISE THROUGH THE 30S IN THOSE
AREAS. AIR MASS INITIALLY DRY...SO PRECIPITATION MAY BE DELAYED
UNTIL EARLY EVENING. HRRR APPEARS TO BE TRACKING WELL WITH CURRENT
RADAR TRENDS AND IS MUCH FASTER WITH THE PRECIP REACHING THE AREA
THAN THE 12Z NAM. THIS AGREES PRETTY WELL WITH TIMING IN CURRENT
FORECAST SO HAVE NOT MADE ANY ADJUSTMENTS. PRECIPITABLE WATER
INCREASES TO NEAR 1.3 INCHES BY 06Z TUESDAY AND ISENTROPIC LIFT IS
STRONG DURING THIS TIME SO BELIEVE PRECIPITATION MAY BE MODERATE
AT TIMES. MODEL SOUNDINGS INDICATE DEEP WARM NOSE ACROSS THE
REGION TONIGHT AS VERY STRONG LOW LEVEL WARM ADVECTION DEVELOPS.
SOUTHWEST 850MB JETMAX GREATER THAN 60KTS. SHALLOW FREEZING LAYER
LIKELY HOWEVER NORTH OF CAE. LARGE TEMPERATURE GRADIENT EXPECTED
WITH FREEZING TEMPS NORTH OF CAE TONIGHT TO POSSIBLY LOW 50S IN
THE CSRA AS WARM ADVECTION INCREASES AND DEEPENS. TEMPERATURES
EXPECTED TO RISE OVERNIGHT IN THE SOUTHERN AREAS.
WITH DEEP WARM NOSE AND SHALLOW FREEZING LAYER...PRECIPITATION
TYPE MOST LIKELY TO BE FREEZING RAIN IN THE NORTH
MIDLANDS...PIEDMONT AND PEE DEE OVERNIGHT. ICING ESTIMATE UP TO
0.20 INCHES IN THE LANCASTER REGION SEEMS APPROPRIATE GIVEN
EXPECTED QPF. FREEZING RAIN ADVISORY REMAINS IN EFFECT. WINTRY
PRECIPITATION ACROSS THE REST OF THE CWA APPEARS UNLIKELY GIVEN
CURRENT LOW TRACK ACROSS THE SOUTH-CENTRAL MIDLANDS/CSRA.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
BOTH THE NAM AND GFS SHOW THE CENTER OF THE LOW ALONG THE VA/NC
COAST BY 12Z TUESDAY MORNING WITH MOISTURE DECREASING ACROSS THE
AREA AS THE LOW CONTINUES TO SHIFT FURTHER NORTHEAST THROUGH THE
DAY ON TUESDAY. SHORTWAVE ENERGY ASSOCIATED WITH THE TROUGH WILL
PROMOTE A SLIGHT CHANCE OF LIGHT PRECIP TUESDAY MORNING AS IT
CROSSES THE REGION. MODEL SOUNDINGS SUGGEST MOISTURE BECOMING
QUITE SHALLOW EARLY TUESDAY...KEPT LOW CHANCE POPS AND
PRECIPITATION MAINLY LIQUID RAIN ALTHOUGH LIGHT FREEZING
RAIN/DRIZZLE POSSIBLE IN THE NORTH MIDLANDS THROUGH ABOUT 15Z.
DRYING WILL OCCUR BY TUESDAY AFTERNOON. HIGHS ON TUESDAY ARE
FORECAST NEAR 40 NORTH TO THE LOW 50S SOUTH. DECREASING CLOUDS
TUESDAY NIGHT WILL PROMOTE LOWS IN THE UPPER 20S NORTH TO LOWER
30S SOUTH.
HIGHLY AMPLIFIED UPPER TROUGH OVER THE EASTERN CONUS WEDNESDAY
SUPPORTS BELOW NORMAL TEMPERATURES WITH SOME MID AND HIGH LEVEL
CLOUDS ASSOCIATED WITH SHORT WAVE TROUGHS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MODELS ARE IN GOOD AGREEMENT THROUGH FRIDAY NIGHT WITH INCREASING
DIFFERENCES SATURDAY THROUGH MONDAY. HIGHLY AMPLIFIED UPPER LEVEL
PATTERN THROUGH THE LONG TERM WILL KEEP AN UPPER LEVEL RIDGE OVER
THE WEST COAST WITH A TROUGH OVER THE EASTERN US. THIS WILL KEEP
AN ACTIVE PATTERN ACROSS THE FORECAST AREA WITH SYSTEMS EVERY
COUPLE OF DAYS. HIGH PRESSURE ALONG WITH COOLER AND DRIER AIR WILL
BUILD INTO THE REGION WEDNESDAY NIGHT WITH THE UPPER LEVEL TROUGH
AXIS JUST WEST OF THE REGION. THE HIGH WILL BE CENTERED JUST NORTH
OF THE REGION ON THURSDAY THEN EJECT NORTHEASTWARD ON FRIDAY AS
THE NEXT LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES REGION
WITH A SECONDARY LOW EXPECTED TO DEVELOP IN CENTRAL TX. MODELS
DIFFER ON THE HANDLING OF THE TX LOW...HOWEVER AGREE ON A FRONTAL
BOUNDARY ACROSS THE FORECAST AREA FOR FRIDAY NIGHT THROUGH MONDAY.
HAVE TRENDED MUCH OF THE LONG TERM TOWARD THE GFS AS RUN TO RUN
CONSISTENCY HAS BEEN BETTER THEN THE ECMWF WHICH HAS MADE
SIGNIFICANT RUN TO RUN CHANGES REGARDING THE TX LOW. TEMPERATURES
THROUGH THE LONG TERM WILL BE SLIGHTLY TO WELL BELOW NORMAL.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS THROUGH LATE AFTERNOON THEN MVFR/IFR CONDITIONS FOR
THE REMAINDER OF THE PERIOD.
LOW PRESSURE OVER EASTERN TX WILL MOVE THROUGH THE GULF STATES
TODAY AND INTO THE TAF SITES TONIGHT. CLOUDS WILL CONTINUE TO
LOWER AND THICKEN THROUGH MID AFTERNOON AS WAST TO SOUTHEASTERLY
WINDS PUSH MOISTURE INTO THE AREA. SCATTERED SHOWERS AND MVFR
CIGS WILL MOVE INTO THE AREA AROUND 21Z...HOWEVER EXPECT MORE
WIDESPREAD RAIN WITH MVFR CIGS AND VSBYS TO ENTER THE TAF SITES
AROUND 17/02Z. IFR CIGS WILL MOVE INTO THE TAF SITES LATE IN THE
PERIOD AS THE COLD FRONT CROSSES THE AREA WITH WINDS QUICKLY
VEERING TO WESTERLY AT THE END OF THE PERIOD. FREEZING RAIN IS
NOT EXPECTED AT THE TAF SITES.
EXTENDED AVIATION OUTLOOK...MVFR...POSSIBLE IFR...RESTRICTIONS
COULD LINGER INTO TUESDAY NIGHT. BREEZY CONDITIONS EXPECTED
WEDNESDAY.
&&
.FIRE WEATHER...
A RED FLAG FIRE ALERT ISSUED BY THE SC FORESTRY COMMISSION
REMAINS IN EFFECT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
TUESDAY FOR SCZ015-016-020>022.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
924 PM CST TUE FEB 17 2015
.SHORT TERM...
320 PM CST
TONIGHT THROUGH THURSDAY...
MAIN CONCERN IS WITH BITTERLY COLD TEMPERATURES AND WIND CHILLS AS
NEAR RECORD COLD AIR MASS FOR MID TO LATE FEBRUARY IMPACTS THE AREA.
IN ADDITION...EXPECTING FAIRLY WIDESPREAD SNOW SHOWERS LATE TONIGHT
INTO WEDNESDAY MORNING.
MORNING RAOBS SHOWED HEART OF COLD AIR MASS...WITH 850 MB TEMPS OF
ABOUT -25 TO -30C FROM KINL UP TO HUDSON BAY. STRONG PV ANOMALY ON
LEADING EDGE OF THIS AIR MASS IS NOTED ON W/V IMAGERY FROM EASTERN
DAKOTAS INTO WESTERN ONTARIO AND THIS WILL MOVE OVER THE AREA
TONIGHT INTO EARLY THURSDAY. IN NEAR TERM...WILL CONTINUE TO SEE
OCCASIONAL FLURRIES...WITH LINGERING SNOW SHOWERS EXITING NW
INDIANA. FORCING FROM UPPER WAVE/PV ANOMALY AND STEEPENING OF
LAPSE RATES SHOULD RESULT IN FAIRLY WIDESPREAD SCATTERED SNOW
SHOWERS PIVOTING SOUTHEASTWARD FROM AROUND MIDNIGHT TONIGHT
THROUGH EARLY THURSDAY MORNING. SIMILAR TO PREVIOUS OCCURRENCES
WITHIN THE PAST WEEK...NOT ALL AREAS WILL SEE ACCUMULATIONS...BUT
WOULDNT BE SURPRISED IF HEAVIER SNOW SQUALLS ARE EMBEDDED WITHIN
SCATTERED SNOW SHOWER ACTIVITY...YIELDING LOCALLY 1/2 INCH TO 1
INCH ACCUMS AND SIGNIFICANTLY REDUCED VISIBILITY. COLD ADVECTION
SHOULD FORCE TEMPERATURES DOWN TO ROUGHLY 0 TO +6 RANGE BY
DAYBREAK WEDNESDAY.
TEMPERATURE TRENDS ARE TRICKY ON WEDNESDAY BECAUSE OF HOW ANOMALOUS
AIR MASS IS. MINUS MID TO UPPER 20S CELSIUS AIR MASS AT 850 MB PROGGED BY
LATE IN THE DAY IS AMONGST THE COLDEST OBSERVED AT ILX/DVN IN THE
MONTH OF FEBRUARY...AND ESPECIALLY THIS LATE IN THE MONTH. HAVE
SHOWN A VERY MINIMAL RECOVERY FROM MORNING LOWS INTO MID DAY/HIGHS
MID TO HIGH POSITIVE SINGLE DIGITS/FOLLOWED BY A FALL IN THE
AFTERNOON..BUT THIS VERY WELL COULD BE OVERDONE. BEST FORCING WILL
BE OFF TO EAST...BUT DEEP UPPER TROUGH REMAINING OVERHEAD AND STEEP
LOW LEVEL LAPSE RATES SHOULD KEEP AT LEAST ISOLATED SNOW SHOWERS AND
FLURRIES AROUND INTO EARLY WEDNESDAY AFTERNOON. STRONG LOW LEVEL
COLD ADVECTION WILL CONTINUE THROUGH WEDNESDAY NIGHT...WITH 925 MB
TEMPS IN THE MID MINUS 20S CELSIUS BY EARLY THURSDAY. THUS DESPITE HIGH
PRESSURE REMAINING WELL NORTHWEST AND PRECLUDING RADIATIONAL
COOLING...SUBZERO LOWS ARE EXPECTED CWA WIDE...AND RELATIVELY
UNIFORM RANGING FROM MID MINUS SINGLE DIGITS TO AROUND 10 BELOW.
EVEN DOWNTOWN CHICAGO SHOULD FALL TO SEVERAL DEGREES BELOW ZERO.
WILL NEED A WIND CHILL ADVISORY FOR THE ENTIRE CWA WEDNESDAY
EVENING/NIGHT THROUGH THURSDAY MORNING...WITH LOWEST VALUES
RANGING FROM 20 TO 30 BELOW ZERO.
THERMAL TROUGH WILL ONLY SLOWLY DEPART TO THE NORTHEAST ON
THURSDAY...SO AFTER BITTERLY COLD START TO DAY...CONTINUE TO
FORECAST RECORD/NEAR RECORD LOW HIGH TEMPERATURES IN THE LOW TO MID
POSITIVE SINGLE DIGITS. SEE CLIMATE SECTION FOR ADDITIONAL DETAILS.
REGARDING LAKE EFFECT POTENTIAL ON WEDNESDAY INTO WEDNESDAY
NIGHT...GUIDANCE CONTINUES TO FOCUS MAINLY EAST OF PORTER COUNTY
WITH WNW BOUNDARY LAYER FLOW. HOWEVER...WITH EXTREME COLD AIR MASS
OVER RELATIVELY MILD LAKE WATERS...COULD STILL SEE SOME MINOR
ACCUMULATIONS IN NORTHEAST PORTER COUNTY IN LIGHT MULTI-BAND SNOW
SHOWERS.
RC
&&
.LONG TERM...
355 PM CST
THURSDAY NIGHT THROUGH TUESDAY...
NO REAL END IN SIGHT TO THE COLD PATTERN...THOUGH THERE WILL BE
SOME MODERATION AT THE BEGINNING OF THE WEEKEND. THURSDAY NIGHT`S
LOWS WILL DEPEND ON HOW QUICKLY CLOUD COVER INCREASES FROM THE
WEST AND SOUTHWEST. ARCTIC HIGH WILL BE OVERHEAD FOR PART OF THE
NIGHT BEFORE SLIDING SOUTHEAST BY DAYBREAK. THERE WILL BE SLOW
WARM ADVECTION ALOFT...BUT ASSUMING SKIES REMAIN MOSTLY
CLEAR/PARTLY CLOUDY THROUGH AT LEAST PART OF
OVERNIGHT...RADIATIONAL COOLING WILL ENABLE SUBZERO LOWS CWA WIDE
AGAIN. COLDEST SPOTS IN NORTHERN IL COULD FALL TO 10 BELOW OR
SLIGHTLY LOWER. MUCH LIGHTER WINDS SHOULD PRECLUDE NEED FOR
ANOTHER WIND CHILL ADVISORY THURSDAY NIGHT.
ON FRIDAY INTO SATURDAY...BIT OF A COMPLEX SETUP WITH MODEL
VARIANCE REGARDING HANDLING MULTIPLE MID LEVEL SHORTWAVES. SOME 12Z
GUIDANCE BROUGHT ACROSS LEAD NORTHERN STREAM WAVE/CLIPPER ON
FRIDAY...FOR WHICH SLIGHT CHANCE TO LOW CHANCE (IN FAR) NORTH POPS
WERE CONTINUED. GFS OPERATIONAL/GEFS AND EUROPEAN ENSEMBLE THEN
INDICATE POTENTIAL FOR MORE WIDESPREAD PRECIPITATION FROM MID LEVEL
WAVE AND ASSOCIATED SURFACE LOW MOVING FROM SOUTHERN PLAINS TO
OHIO VALLEY ON SATURDAY INTO SUNDAY. DESPITE DRIER TREND TODAY
FROM OPERATIONAL ECMWF...OP GFS/GEFS MEAN AND INDIVIDUAL
MEMBERS/ECMWF ENSEMBLE MEAN AND SOME INDIVIDUAL MEMBERS/ALL HAVE
TRACK MORE FAVORABLE FOR WIDESPREAD SNOW AREA WIDE. FOR NOW HAVE
HIGHEST CHANCE POPS SOUTH OF INTERSTATE 80...BUT THIS PERIOD WILL
NEED TO BE WATCHED FOR HOW WELL VARIOUS SHORT WAVES
INTERACT/PHASE. HIGHS WILL MODERATE FROM NEAR/AROUND 20 ON FRIDAY
TO UPPER 20S/LOW 30S ON SATURDAY...THEN COOL BACK WELL BELOW
NORMAL FOR THE REST OF THE EXTENDED. 12Z OPERATIONAL ECMWF SHOWED
ANOTHER SHOT OF EXTREME COLD BEYOND DAY 7...WHICH ANYONE THAT IS
GROWING TIRED OF THE VERY COLD WEATHER CAN ONLY HOPE DOESNT COME
TO FRUITION.
RC
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE RECORD LOW
MAXIMUM TEMPERATURES.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE AT ALMOST ANYTIME
THROUGH WEDNESDAY
* BEST SHOT OF MORE SUBSTANTIAL SHSN APPEARS TO BE LATE TONIGHT
THROUGH MID-MORNING WEDNESDAY
* GUSTY NORTHWEST WINDS DEVELOP WEDNESDAY MORNING AND CONTINUE
THROUGH AFTERNOON
IZZI
//DISCUSSION...UPDATED 00Z...
UNSEASONABLY COLD AIR WILL REMAIN ENTRENCHED OVER THE REGION WITH
FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE AT JUST ABOUT ANY
POINT IN TIME DURING THE NEXT 24 HOURS. BETTER CHANCE OF MORE
ROBUST BUT STILL OCNL SNOW SHOWERS WITH REDUCED VSBY AND CHANCE TO
PRODUCE A COATING OF SNOW APPEARS TO BE LATE TONIGHT INTO
WEDNESDAY MORNING ASSOCIATED WITH RE-ENFORCING SHOT OF ARCTIC
AIR. THE RENEWED ARCTIC AIR BLAST WILL LIKELY BE ACCOMPANIED BY
STRONGER AND FAIRLY GUSTY NORTHWEST WINDS DEVELOPING WEDNESDAY
MORNING AND LASTING THROUGH THE AFTERNOON. LOOK FOR SCT V BKN
CONDITIONS WITH CIG HEIGHTS PRIMARILY BETWEEN FL025-035 BUT WITH
SOME VARIABILITY OUTSIDE OF THIS RANGE POSSIBLE FROM TIME TO
TIME.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE IN TIMING OF BEST CHANCE OF MORE SUBSTANTIAL
SNOW SHOWER THREAT
* FAIRLY HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...VFR. MODERATELY STRONG SOUTH WINDS. BECOMING MVFR AT
NIGHT WITH SNOW/IFR POSSIBLE.
SATURDAY...MVFR CIGS POSSIBLE. CHANCE OF MVFR AND -SN.
SUNDAY...MVFR CIGS POSSIBLE.
MONDAY...PRIMARILY VFR.
IZZI
&&
.MARINE...
336 PM CST
WESTERLY WINDS IN PLACE LATE THIS AFTERNOON ARE EXPECTED TO BECOME
MORE NORTHERLY TONIGHT AS LOW PRESSURE DEPARTS TO THE EAST AND
HIGH PRESSURE BUILDS OVER THE CENTRAL PART OF THE US. SPEEDS WILL
ALSO INCREASE TONIGHT AS THE SURFACE GRADIENT TIGHTENS AND HAS
COLDER AIR CONTINUES TO SPILL SOUTH ACROSS THE REGION...WITH WINDS
TO 30 KT LIKELY. INCREASING WINDS WILL CONTINUE ON WEDNESDAY WITH
GALES LIKELY PRIMARILY ON THE SOUTHERN HALF OF THE
LAKE...ALTHOUGH....A SMALL WINDOW OF GALE FORCE GUSTS DO APPEAR
POSSIBLE ACROSS THE NORTH HALF WEDNESDAY AFTERNOON. SO HAVE ISSUED
A GALE WARNING FOR THE SOUTH HALF AS WELL AS A HEAVY FREEZING
SPRAY WARNING FOR WEDNESDAY INTO WEDNESDAY EVENING. NORTHWEST
WINDS WILL SLOWLY DIMINISH WEDNESDAY NIGHT INTO THURSDAY...BUT
WITH WINDS TO 30KT STILL LIKELY.
RODRIGUEZ
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878...6 AM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM
WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ745...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
903 PM CST Tue Feb 17 2015
.UPDATE...
ISSUED AT 903 PM CST TUE FEB 17 2015
Light snow is moving into the area this evening and will continue
during the overnight hours. Very difficult to see all of it on
radar given how shallow the clouds are and that all radars are
overshooting it out in northeast MO and west central IL. So, based
on observations, it appears most of the light snow will be along
and south of I-74. So will be making adjustments to pop/wx grids
to accommodate expected location of snowfall. Short term models:
HRRR seems too fast with pushing the snow through. First glance at
the NAM looks ok and keeps snow going in the east and southeast
overnight. Clouds and winds look fine, but will be making some
minor adjustments to low temps. Update will be out shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 320 PM CST TUE FEB 17 2015
Slightly complicated forecast in the short term as the long wave
trof rotates around and through the region tonight, with a couple
shortwaves on satellite imagery. HRRR and RUC/RAPP both producing
more qpf with prev runs and clearly picking up on some snow showers
out to the west. NAM/GFS picking up on it, but mainly concentrating
on wave to the south. As a result, two additions to tonights
forecast...one with the southwest CWA in a line from roughly
Jacksonville to Springfield to Paris...potential for a few tenths of
snowfall. Up to an inch possible, but better chances will be to the
south, where the second change to the forecast is with the more
southerly wave...an inch/inch and a half are possible. Behind the
snow as morning approaches, the northwesterly winds will continue to
increase. Temperatures will mainly run slightly off the normal
diurnal curve as the cold air mass moves southward into the region.
By early morning hours, wind chills will drop to -10 to -15F NW of
the Illinois River Valley.
&&
.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 320 PM CST TUE FEB 17 2015
Another reinforcing push of cold air will move into central Illinois
behind another pressure trough early Wednesday. Very cold arctic air
will result in highs only in the single digits with brisk northwest
winds 15-20 mph and gusts to around 30 mph. Went below MOS guidance
for highs Wed due to extreme variation from climatology and due to
snow cover over portions of the forecast area. As a result, wind
chill values will be below -15 F for much of the area northwest of
the Illinois River and have issued a wind chill advisory from 5 a.m.
to noon. Wind chill temperatures should be just above wind chill
criteria...-10 F or so for the afternoon, but still very cold. Winds
will settle down somewhat overnight Wednesday night causing
temperatures to drop below zero throughout central IL, but wind
chills look to drop to around -15 to -20 F and may need another wind
chill advisory.
Deep upper level trof shifts east of IL Thu night and Friday while
arctic high pressure also drifts east of IL across the Ohio river
valley Thu night and Fri morning. Temps will be slow to climb on
Friday due to mostly cloudy skies with highs in the low to mid 20s.
Have small chances of light snow Friday afternoon as moist warm
advection affects the region.
Extended models coming to better agreement on track of southern
stream storm system this weekend, with track of low passing the
southern tip of Illinois Saturday. Looks cold enough for mainly
light snow, though continue with a mix over southeast IL on Sat.
Have just slight chance of light snow Sunday and then dry across
area by Sunday evening. Highs in the low to mid 30s Sat cool off
again early next week on Sunday and Monday behind this storm
system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 552 PM CST TUE FEB 17 2015
VFR conditions continue at all sites this evening. However, a
short wave is moving toward the area this evening and should bring
some light snow to some of the sites. SPI could see the most of it
in the next few hours, reducing vis this evening to around 4sm
with the snow starts. Conditions could get a little worse
beginning around midnight, so will have a TEMPO group for 4hrs
with vis around 2sm and cigs around 2.5kft. DEC and CMI could see
lower conditions overnight as well but will just have TEMPO groups
for them since most of the snow should be south of those two
sites. PIA and BMI will just have some flurries as they are
further north of the main short wave. Once the wave goes by and
all the snow has ended, cigs will drop to MVFR conditions around
2.5kft starting tomorrow morning and continuing through the day.
Models showing some sort of break in the clouds, but believe with
the continued CAA tomorrow, lower clouds will fill in any holes
during the day. Winds will be primarily west to northwest and
around 08-10kts tonight. Tomorrow winds will still be northwest
and increase in speed, with gusts of 25-27kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 5 AM to Noon CST Wednesday FOR
ILZ027>029-036-040.
&&
$$
UPDATE...Auten
SHORT TERM...HJS
LONG TERM...Onton
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
152 PM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT AND VARIABLE WINDS THROUGH LATE AFTERNOON...THEN BECOMING
SWLY-WLY OVERNIGHT WITH SPEEDS ARND 5-7KT.
* SWLY WINDS 10-15KT TOMORROW.
* MVFR CIGS LIKELY LATE TONIGHT WITH...SOME FLURRIES OR LIGHT
SNOW SHOWERS POSSIBLE.
KREIN
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER CANADA AND THE LOWER MISSISSIPPI VALLEY COMBINED
WITH HIGH PRESSURE OVER THE ERN GREAT LAKES AND WESTERN PLAINS HAS
SET UP A COL OVER THE REGION...WITH CALM TO LIGHT AND VARIABLE
WINDS. THE ONLY CLOUD COVER OF SIGNIFICANCE THIS AFTERNOON WILL BE
THE NORTHERN EDGE OF JET STREAM CIRRUS...WITH A STRONG UPPER LEVEL
JET OVER THE OHIO VALLEY. A WEAK SFC TROUGH/COLD FRONT DROPPING
SWD OUT OF THE UPPER MISSISSIPPI VALLEY TONIGHT WILL BRING
INCREASING LOW AND MID CLOUD. WITH A VERY DRY AIRMASS IN
PLACE...THE CHANCES FOR PRECIPITATION ACCOMPANYING THE FRONT ARE
LOW...BUT THERE COULD BE ENOUGH FORCING TO GENERATE SOME SCT
FLURRIES OR LIGHT SNOW SHOWERS...WITH MVFR CIGS. HOWEVER...ANY
SNOW THAT DOES DEVELOP SHOULD HAVE LITTLE OR NO ADDITIONAL IMPACT.
FOLLOWING THE FROPA TOMORROW...WINDS WILL SHIFT TO NORTHWESTERLY
AND THE RESULTANT INCREASING COLD ADVECTION THROUGH THE DAY SHOULD
LEAD TO WINDS INCREASING TO 10-15KT WITH OCNL HIGHER GUSTS OF
18-20KT.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS TONIGHT. MEDIUM CONFIDENCE IN
TIMING AND DURATION.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.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:
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WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1148 AM CST Mon Feb 16 2015
.UPDATE...
ISSUED AT 1041 AM CST MON FEB 16 2015
Made a quick update to the forecast to lower PoPs along the
northern edge of the snow area and to drop the Winter Weather
Advisory for Scott, Morgan, Sangamon, and Christian counties.
16z/10am radar mosaic shows light to moderate snow ongoing across
the southern KILX CWA, mainly along/south of a Paris to
Shelbyville line. Still some weak echoes further west just
south of Quincy, so some additional light snow/flurries will
remain possible as far north as Springfield through midday. After
that, the snow area will gradually shift further southeastward and
dissipate as the day progresses. Additional accumulations of
around 1 inch are likely along/south of I-70 through the afternoon
before the snow tapers off to flurries and ends. Elsewhere around
central Illinois, cold and dry conditions will prevail. High temps
will only rise into the lower 20s.
&&
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulating snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1148 AM CST MON FEB 16 2015
VFR conditions will prevail at the central Illinois terminals this
afternoon and evening before lower clouds poised well to the
northwest behind an approaching cold front spill into the area
later tonight into Tuesday. Upstream obs show widespread low VFR
ceilings of around 3500ft just ahead of the system across much of
Iowa, with MVFR ceilings behind the boundary across Minnesota into
northern Iowa. Based on satellite timing tools and 12z NAM FROPA,
have introduced MVFR conditions at KPIA by 11z, then further east
to KCMI by 14z. Scattered flurries will occur along/behind the
front within the CAA regime: however, opted to leave mention of
precip out of the forecast. Winds will initially be from the N/NE
at around 5kt this afternoon, but will back to the W/SW ahead of
the system this evening. Once cold front passes, winds will become
northwesterly at around 10kt by late Tuesday morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ061>063.
&&
$$
UPDATE...Barnes
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1130 AM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT AND VARIABLE WINDS THROUGH LATE AFTERNOON...THEN BECOMING
SWLY-WLY OVERNIGHT WITH SPEEDS ARND 5-7KT.
* SWLY WINDS 10-15KT TOMORROW.
* MVFR CIGS LIKELY LATE TONIGHT WITH...SOME FLURRIES OR LIGHT
SNOW SHOWERS POSSIBLE.
KREIN
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE OVER CANADA AND THE LOWER MISSISSIPPI VALLEY COMBINED
WITH HIGH PRESSURE OVER THE ERN GREAT LAKES AND WESTERN PLAINS HAS
SET UP A COL OVER THE REGION...WITH CALM TO LIGHT AND VARIABLE
WINDS. THE ONLY CLOUD COVER OF SIGNIFICANCE THIS AFTERNOON WILL BE
THE NORTHERN EDGE OF JET STREAM CIRRUS...WITH A STRONG UPPER LEVEL
JET OVER THE OHIO VALLEY. A WEAK SFC TROUGH/COLD FRONT DROPPING
SWD OUT OF THE UPPER MISSISSIPPI VALLEY TONIGHT WILL BRING
INCREASING LOW AND MID CLOUD. WITH A VERY DRY AIRMASS IN
PLACE...THE CHANCES FOR PRECIPITATION ACCOMPANYING THE FRONT ARE
LOW...BUT THERE COULD BE ENOUGH FORCING TO GENERATE SOME SCT
FLURRIES OR LIGHT SNOW SHOWERS...WITH MVFR CIGS. HOWEVER...ANY
SNOW THAT DOES DEVELOP SHOULD HAVE LITTLE OR NO ADDITIONAL IMPACT.
FOLLOWING THE FROPA TOMORROW...WINDS WILL SHIFT TO NORTHWESTERLY
AND THE RESULTANT INCREASING COLD ADVECTION THROUGH THE DAY SHOULD
LEAD TO WINDS INCREASING TO 10-15KT WITH OCNL HIGHER GUSTS OF
18-20KT.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS TONIGHT. MEDIUM CONFIDENCE IN
TIMING AND DURATION.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.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
1042 AM CST Mon Feb 16 2015
.UPDATE...
ISSUED AT 1041 AM CST MON FEB 16 2015
Made a quick update to the forecast to lower PoPs along the
northern edge of the snow area and to drop the Winter Weather
Advisory for Scott, Morgan, Sangamon, and Christian counties.
16z/10am radar mosaic shows light to moderate snow ongoing across
the southern KILX CWA, mainly along/south of a Paris to
Shelbyville line. Still some weak echoes further west just
south of Quincy, so some additional light snow/flurries will
remain possible as far north as Springfield through midday. After
that, the snow area will gradually shift further southeastward and
dissipate as the day progresses. Additional accumulations of
around 1 inch are likely along/south of I-70 through the afternoon
before the snow tapers off to flurries and ends. Elsewhere around
central Illinois, cold and dry conditions will prevail. High temps
will only rise into the lower 20s.
&&
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulating snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 600 AM CST MON FEB 16 2015
VFR conditions are expected across the I-74 TAF sites while MVFR
cigs in snow can be expected at times at SPI and DEC this morning.
Cigs could dip down to 2000 feet in some of the steadier snows at SPI,
with periods of 3500 feet where there are breaks in the precip. The
snow should begin to shift southeast of SPI and DEC between 14 and
16z this morning, but MVFR cigs could linger into afternoon. Surface
winds will continue to be relatively light through the period with a
east to northeast wind this morning at 6 to 9 kts. Winds will
back more into a northerly direction this afternoon, then become
SW later tonight ahead of a shortwave. Some MVFR cigs are
projected to affect the I-74 TAF sites after 06z, with a few
flurries possible.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ061>063.
&&
$$
UPDATE...Barnes
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
805 AM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* SOUTHEAST WINDS TURN SOUTH THEN SOUTHWEST INTO THE
AFTERNOON...WITH VARIABILITY IN DIRECTION. SPEEDS UNDER 10 KT.
* MVFR CIGS POSSIBLE TONIGHT ALONG WITH SOME FLURRIES.
KREIN
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS CENTERED EAST OF THE AREA THIS MORNING WHICH HAS
ALLOWED SOUTHEAST WINDS TO BECOME LIGHT. THE HIGH WILL SHIFT EAST
AND A COLD FRONT WILL DROP SOUTHEAST ACROSS THE AREA TONIGHT.
WINDS WILL TURN SOUTH THEN SOUTHWEST INTO THE AFTERNOON AS THE
HIGH DEPARTS. EXPECT TO SEE SOME VARIABILITY IN WIND DIRECTION
THROUGH THE DAY BUT SPEEDS WILL BE UNDER 10 KT AND PROBABLY AROUND
5 KT FOR MUCH OF THE PERIOD. THE COLD FRONT AND ASSOCIATED UPPER
TROUGH CROSS THE AREA LATER TONIGHT. A PERIOD OF MVFR CIGS MAY
DEVELOP LATE THIS EVENING OR EARLY TONIGHT. IN ADDITION SOME SNOW
FLURRY ACTIVITY WILL PROBABLY DEVELOP BUT HAVE NOT INCLUDED ANY
-SN IN THE TAF GIVEN THAT THE POTENTIAL IS LOW AND NO ACCUMULATION
IS EXPECTED. WINDS WILL TURN NORTHWESTERLY AND MODESTLY INCREASE
IN SPEED TUESDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN MVFR CIGS TONIGHT. LOW-MEDIUM CONFIDENCE IN
TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.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
600 AM CST Mon Feb 16 2015
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulating snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 600 AM CST MON FEB 16 2015
VFR conditions are expected across the I-74 TAF sites while MVFR
cigs in snow can be expected at times at SPI and DEC this morning.
Cigs could dip down to 2000 feet in some of the steadier snows at SPI,
with periods of 3500 feet where there are breaks in the precip. The
snow should begin to shift southeast of SPI and DEC between 14 and
16z this morning, but MVFR cigs could linger into afternoon. Surface
winds will continue to be relatively light through the period with a
east to northeast wind this morning at 6 to 9 kts. Winds will
back more into a northerly direction this afternoon, then become
SW later tonight ahead of a shortwave. Some MVFR cigs are
projected to affect the I-74 TAF sites after 06z, with a few
flurries possible.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ049>052-061>063.
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
546 AM CST MON FEB 16 2015
.SHORT TERM...
329 AM CST
THROUGH THURSDAY...
TEMPERATURES AND WIND CHILLS WILL BE THE PRIMARY FORECAST
CONCERN...ESPECIALLY BY MID TO LATE WEEK AS A POTENTIALLY RECORD
BREAKING ARCTIC AIR MASS TAKES HOLD OF THE AREA FOR A COUPLE OF DAYS.
TEMPERATURES TODAY SHOULD WARM A FEW DEGREES WARMER THAN THOSE
OBSERVED ON SUNDAY. OVERALL...THIS SHOULD PUT HIGHS IN THE UPPER
TEENS TO THE LOW 20S ACROSS THE REGION. A SIGNIFICANT WINTER
STORM...WHICH IS CURRENTLY IMPACTING AREAS FROM CENTRAL ILLINOIS
SOUTHWARD...WILL CONTINUE TO SPREAD ACCUMULATING SNOW ACROSS THIS
REGION TODAY. FOR NORTHERN ILLINOIS AND NORTHWESTERN INDIANA...ALL
WE SHOULD HAVE TO DEAL WITH IS SOME HIGHER LEVEL CLOUDINESS DURING
THE DAY TODAY.
AS STATED IN THE PREVIOUS DISCUSSION...A SIGNIFICANT PIECE OF THE
POLAR VORTEX WILL BE DISLODGED AND FORCED SOUTHWARD OVER THE GREAT
LAKES REGION BY MID WEEK. THIS SHOULD ALLOW A TRUE ARCTIC AIR MASS
FEATURING -20 TO -24 DEGREE CELSIUS 925 MB TEMPERATURES TO SHIFT OUT
OF THE NORTHWEST TERRITORIES OF CANADA RIGHT ACROSS THE CENTRAL
PORTION OF THE COUNTRY. GUIDANCE CONTINUES IN GOOD AGREEMENT WITH THE
HEAT OF THIS AIR MASS MOVING OVER NORTHERN ILLINOIS/NORTHWESTERN
INDIANA ON THURSDAY. THIS TYPE OF AIR MASS IS CAPABLE OF PRODUCING
HIGH TEMPERATURES IN SINGLE DIGITS ABOVE ZERO AREA-WIDE...AND IF
THIS MATERIALIZES COULD RESULT IN RECORD COLD MAX TEMPERATURES FOR
THE DATE ON THURSDAY. SEE CLIMO SECTION BELOW FOR TEMPERATURE
RECORDS FOR CHICAGO AND ROCKFORD.
UNFORTUNATELY...WITH THESE BITTERLY COLD TEMPERATURES WE HAVE TO
TALK ABOUT WIND CHILLS AGAIN. WITH THE LIKELIHOOD OF A 10 TO 15 KT
SUSTAINED NORTHWESTERLY WIND FOR MUCH OF THE PERIOD INTO
THURSDAY...WIND CHILLS WILL LIKELY REACH ADVISORY LEVEL CRITERIA OF
-20 TO -30...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY. THIS WOULD BE
THE MOST LIKELY PERIOD OF WIND CHILLS FALLING BELOW -20.
HOWEVER...TUESDAY NIGHT AND THURSDAY NIGHT WILL NOT FAVOR MUCH
BETTER...AND COULD BE CLOSE IN MY NORTHERN AREAS FOR NEEDING A
HEADLINE. EITHER WAY YOU LOOK AT IT...IT WILL BE VERY COLD.
ALTHOUGH NO BIG SNOW EVENTS ARE EXPECTED OVER THE NEXT FEW
DAYS...THERE WILL LIKELY BE PERIODS OF FLURRIES AT TIMES TONIGHT
INTO WEDNESDAY AS SEVERAL MINOR MID LEVEL DISTURBANCES IMPACT THE
AREA. HOWEVER...IT APPEARS THE BEST CHANCE FOR SOME BETTER SNOW
SHOWER ACTIVITY..WITH SOME POSSIBLE MINOR ACCUMULATIONS COULD ENTER
THE PICTURE LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DURING THIS
PERIOD...A SIGNIFICANT PV ANOMALY IS EXPECTED TO SHIFT ACROSS THE
AREA. FORCED LARGE SCALE ASCENT FROM THIS FEATURE...COMBINED WITH
STEEPENING LOW LEVEL LAPSE RATES WITH ARRIVAL OF THE ARCTIC AIR MASS
COULD RESULT IN A FEW SNOW SQUALLS...POTENTIALLY RESULTING IN SOME
MINOR ACCUMULATING SNOWS OVER THE AREA INTO EARLY WEDNESDAY.
THE DEEP ARCTIC AIR MASS WILL ALSO GET LAKE EFFECT SNOWS GOING AGAIN
LATER TONIGHT THROUGH THURSDAY. HOWEVER...IT CONTINUES TO LOOK AS
THOUGH MUCH OF THE FOCUS FOR THIS ACTIVITY WILL REMAIN LARGELY ALONG
THE EASTERN AND SOUTHERN SHORES OF LAKE MICHIGAN. WE WILL CONTINUE
TO MENTION SOME CHANCES FOR THESE SHOWERS ACROSS MAINLY NORTHEASTERN
PORTER COUNTIES IN INDIANA DURING MUCH OF THIS PERIOD...BUT IT EVEN
APPEARS THAT MUCH OF THE ACCUMULATION POTENTIAL WILL REMAIN TO THE
EAST.
KJB
&&
.LONG TERM...
329 AM CST
THURSDAY NIGHT THROUGH SUNDAY...
IF THERE IS ANY GOOD NEWS WITH THIS COLD AIR OUTBREAK...IT WOULD
BE THAT IT LOOKS TO BE FAIRLY PROGRESSIVE. THEREFORE...WARMER
CONDITIONS SHOULD BEGIN TO SET UP ACROSS THE REGION BY FRIDAY AND
INTO NEXT WEEKEND. HOWEVER...THIS WILL BE NO MEANS BE A WARM
SPELL...TEMPERATURES WILL STILL REMAIN BELOW NORMAL THROUGH...AND
BEYOND THE CURRENT FORECAST PERIOD. SOMETIMES THE MODELS DO TRY TO
ERODE THE COLD AIR TOO FAST...SO IT IS POSSIBLE THAT THE WARM UP
COULD BE SLOWER THAN CURRENTLY FORECAST.
THE OTHER CONCERN DURING THE LATER PORTION OF THE PERIOD WILL BE
THE POTENTIAL FOR A MORE ACTIVE PERIOD OF WEATHER...PARTICULARLY
LATE FRIDAY AND INTO THE WEEKEND. MODEL GUIDANCE CONTINUES TO SHOW
CONSIDERABLE DISAGREEMENT FOLLOWING THE PASSAGE OF THE HEART OF
THE MIDWEEK ARCTIC AIR MASS. THEREFORE CONFIDENCE ON SNOWFALL
POTENTIAL ACROSS THE AREA DURING THIS PERIOD REMAINS LOW.
KJB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE LOW MAXS.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* SOUTHEAST WINDS TURN SOUTH THEN SOUTHWEST INTO THE
AFTERNOON...WITH VARIABILITY IN DIRECTION. SPEEDS UNDER 10 KT.
* MVFR CIGS POSSIBLE TONIGHT ALONG WITH SOME FLURRIES.
MDB
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE IS CENTERED EAST OF THE AREA THIS MORNING WHICH HAS
ALLOWED SOUTHEAST WINDS TO BECOME LIGHT. THE HIGH WILL SHIFT EAST
AND A COLD FRONT WILL DROP SOUTHEAST ACROSS THE AREA TONIGHT.
WINDS WILL TURN SOUTH THEN SOUTHWEST INTO THE AFTERNOON AS THE
HIGH DEPARTS. EXPECT TO SEE SOME VARIABILITY IN WIND DIRECTION
THROUGH THE DAY BUT SPEEDS WILL BE UNDER 10 KT AND PROBABLY AROUND
5 KT FOR MUCH OF THE PERIOD. THE COLD FRONT AND ASSOCIATED UPPER
TROUGH CROSS THE AREA LATER TONIGHT. A PERIOD OF MVFR CIGS MAY
DEVELOP LATE THIS EVENING OR EARLY TONIGHT. IN ADDITION SOME SNOW
FLURRY ACTIVITY WILL PROBABLY DEVELOP BUT HAVE NOT INCLUDED ANY
-SN IN THE TAF GIVEN THAT THE POTENTIAL IS LOW AND NO ACCUMULATION
IS EXPECTED. WINDS WILL TURN NORTHWESTERLY AND MODESTLY INCREASE
IN SPEED TUESDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN MVFR CIGS TONIGHT. LOW-MEDIUM CONFIDENCE IN
TIMING.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...CHANCE OF SNOW SHOWERS. MVFR CIGS POSSIBLE. WEST-
NORTHWEST WINDS.
WEDNESDAY...CHANCE OF FLURRIES. MVFR CIGS POSSIBLE. BREEZY NORTHWEST
WINDS.
THURSDAY...MAINLY VFR. NORTHWEST WINDS.
FRIDAY...CHANCE OF SNOW ESPECIALLY FRIDAY NIGHT. MVFR/IFR POSSIBLE
LATE. SOUTH WINDS.
SATURDAY...CHANCE OF SNOW ESPECIALLY IN THE MORNING. MVFR
POSSIBLE. SOUTHWEST WINDS BECOMING NORTHWEST.
SUNDAY...MVFR POSSIBLE. NORTH WINDS.
MDB
&&
.MARINE...
220 AM CST
HIGH PRESSURE OVER LAKE HURON AND LAKE ERIE WILL MOVE EASTWARD
TODAY WHILE A COLD FRONT/TROUGH ACROSS THE NORTHERN PLAINS THIS
MORNING TRACKS SOUTHEAST. THE FRONT WILL CROSS LAKE MICHIGAN
TONIGHT SHIFTING SOUTHERLY WINDS TO THE NORTHWEST. A WEAK LOW WILL
THEN DROP ACROSS THE LAKE TUESDAY NIGHT BRINGING A BETTER PUSH OF
COLD AIR WITH A STRONG HIGH BUILDING INTO THE PLAINS BEHIND IT.
NORTHWEST WINDS WILL INTENSIFY WEDNESDAY WITH LOW END GALES STILL
LOOKING LIKE A GOOD POSSIBILITY FOR MOST OF WEDNESDAY AND
WEDNESDAY NIGHT ACROSS CENTRAL AND SOUTHERN PORTIONS OF THE LAKE.
WINDS WILL VERY SLOWLY EASE THURSDAY WITH THE PRESSURE GRADIENT
BEING SLOW TO WEAKEN BETWEEN LOW PRESSURE TO THE EAST AND THE
APPROACHING HIGH FROM THE WEST. THE HIGH SHOULD PUSH OVERHEAD
EARLY FRIDAY BRINGING MUCH LIGHTER WINDS BUT THIS WILL BE SHORT
LIVED AS ANOTHER LOW LOOKS TO AFFECT THE REGION EARLY NEXT
WEEKEND. MODEL GUIDANCE IS AT ODDS NEXT WEEKEND SO DO NOT HAVE
MUCH CONFIDENCE IN ANY DETAILS THIS FAR OUT.
WEB CAMS AND SATELLITE IMAGERY SHOW THE ICE FIELD TO BE PRETTY
EXTENSIVE AROUND THE PERIMETER OF THE LAKE SO HAVE REMOVED WAVES
FROM THE NEARSHORE WATERS.
MDB
&&
.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
332 AM CST Mon Feb 16 2015
.SHORT TERM...(Today)
ISSUED AT 332 AM CST MON FEB 16 2015
Winter storm continues relatively on track with previous forecast.
Will not make any timing or coverage changes to the Winter Storm
headlines with the morning update. Counties can be cleared from the
headlines early if needed as the snowfall diminishes from NW to SE
this afternoon.
The 5" snowfall report from Edgewood at 150 am in SW Effingham
county lends confidence that the southeast 6 counties in the Winter
Storm Warning will reach into the 6 to 8" range before the end of
this event. Isolated spots may even climb above 8". Radar trends of
the bands of moderate snows are correlating closely to the RAP and
NAM depiction of 700mb Fn frontogenetic convergence. Projecting
forward through the day, our southeast counties will remain under
waves of Fn convergence and steady snows into the afternoon. Along
I-72, snows will be lighter, but the southern portions of the
advisory counties look on track to climb up to 3" before the
snowfall diminishes on the northern periphery. Have continued with
categorical PoPs in the winter storm warning and advisory areas this
morning, with slight chances up to Lincoln to Paris. PoPs were
trended downward each hour this afternoon to correlate with the
eastward translation of mid level forcing and deep moisture.
Additional accumulations today could reach between 2 to 4" in the
Warning counties S of I-70, with 1 to 2 inches for the southern
portions of the advisory counties between I-70 and I-72. Little to
no snowfall is expected north of a line from Rushville to Lincoln to
Champaign.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 332 AM CST MON FEB 16 2015
Have a 20-30% chance of light snow in far southeast IL early this
evening with little additional accumulations then. Best chance of
accumulationing snows this evening will be southeast of IL over KY
where as much as 10-16 inches of snow is expected. WNW winds will be
less than 10 mph tonight so limiting the amount of blowing and
drifting snow in southeast IL. Lows tonight of 8-13F with coldest
readings over deeper fresh snow cover in southeast IL. A cold front
to move se across central/se IL Tue morning and generally move
through dry with limited moisture. Have chance of flurries ne
counties overnight into Tue while better chances of light snow
further ne closer to MI/Lake MI. Highs Tue in lower 20s se of IL
river and upper teens nw of the IL river.
00Z forecast models continue to dig a strong upper level trof
southward into the Midwest including IL Tue night and Wed with
another surge of arctic air into the region. Scattered flurries with
mostly cloudy skies to accompany this trof along with bitter cold
temperatures. Lows Tue night around 5F. Highs Wed only in lower
teens eastern/se IL and 5-10F from I-55 west. Brisk nw winds Wed
with gusts 20-30 mph to give wind chills of 10-15 below zero
northern counties. Even colder Wed night with lows in the single
digits below zero and wind chills of 15-25 below zero. Wind chill
advisory may be needed wed night into thu morning even for central
and southeast IL. Strong upper level trof starts to shift east of IL
Thu but still very cold Thu with arctic high pressure moving into MS
river valley. Highs Thu of 8-13F and coldest from I-74 ne.
As high pressure drifts east of IL late this week and upper level
heights and 850 mb temps elevate, temps to moderate to mildest
readings on Sat in low to mid 30s for highs. But still below normal
for late Feb. Continued to stay close to guidance chances of light
snow this weekend starting Friday night. Big differences with
extended models this weekend with ECMWF showing strong low pressure
moving ne into IL Sat night while GFS keeps precipitation south of
central IL this weekend. GEM model through Sat is looking drier like
the GFS model. The Climate Prediction Center (CPC) 8-14 day
temperature outlook for Feb 23-Mar 1 has IL in greater than 70%
chance of below normal temperatures.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1100 PM CST SUN FEB 15 2015
VFR conditions are expected across the I-74 TAF sites while MVFR
cigs in snow can be expected at times at SPI and DEC into Monday
morning. Cigs will range from 1200-1500 feet in some of the steadier
snows, to 2500 to 3500 feet where there is a break in the precip.
The snow should begin to shift southeast of SPI and DEC between
12 and 15z Monday morning. Surface winds will continue to be a
non-factor through the period with a east to northeast wind the
remainder of tonight at 8 to 13 kts with winds backing more into
a northerly direction by afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR
ILZ049>052-061>063.
WINTER STORM WARNING until 6 PM CST this evening FOR ILZ066>068-
071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
937 AM EST MON FEB 16 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 16/15Z IND TAF UPDATE/...
ISSUED AT 937 AM EST MON FEB 16 2015
RADAR AND OBSERVATIONAL TRENDS SUGGESTING FAIRLY STEADY LIGHT SNOW
TODAY WITH IFR CONDITIONS.
PREVIOUS DISCUSSION FOLLOWS...
SNOW HAS OVERSPREAD BMG...HUF AND IND...ALTHOUGH THE NORTHERN EXTENT
OF THE PRECIPITATION SHIELD ENDS WITHIN 10-15 MILES OF HUF/IND...AND
THIS SHOULD ROUGHLY BE THE RULE MUCH OF THE DAY.
EXPECT LIFR CONDITIONS TO DEVELOP AND PERSIST AT BMG...AND IFR
CONDITIONS TO DO THE SAME AT HUF/IND...ALTHOUGH CONDITIONS MAY BE
QUITE VARIABLE AT THESE TWO SITES GIVEN PROXIMITY TO THE EDGE OF THE
PRECIP SHIELD. LAF SHOULD REMAIN VFR AND OUT OF THE PRECIPITATION
THROUGH THE DURATION OF THE EVENT.
WINDS WILL REMAIN EASTERLY AT 10KT OR LESS THROUGH THE
DAY...EVENTUALLY SWINGING NORTHERLY AND WESTERLY AS THE LOW PASSES
TO THE SOUTH...WIND CHANGES WILL BE QUICK ENOUGH TONIGHT TO MERIT A
BLANKET VARIABLE DESIGNATION FOR SAKE OF SIMPLICITY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...NIELD/MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
553 AM EST MON FEB 16 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 16/12Z TAFS/...
ISSUED AT 553 AM EST MON FEB 16 2015
SNOW HAS OVERSPREAD BMG...HUF AND IND...ALTHOUGH THE NORTHERN EXTENT
OF THE PRECIPITATION SHIELD ENDS WITHIN 10-15 MILES OF HUF/IND...AND
THIS SHOULD ROUGHLY BE THE RULE MUCH OF THE DAY.
EXPECT LIFR CONDITIONS TO DEVELOP AND PERSIST AT BMG...AND IFR
CONDITIONS TO DO THE SAME AT HUF/IND...ALTHOUGH CONDITIONS MAY BE
QUITE VARIABLE AT THESE TWO SITES GIVEN PROXIMITY TO THE EDGE OF THE
PRECIP SHIELD. LAF SHOULD REMAIN VFR AND OUT OF THE PRECIPITATION
THROUGH THE DURATION OF THE EVENT.
WINDS WILL REMAIN EASTERLY AT 10KT OR LESS THROUGH THE
DAY...EVENTUALLY SWINGING NORTHERLY AND WESTERLY AS THE LOW PASSES
TO THE SOUTH...WIND CHANGES WILL BE QUICK ENOUGH TONIGHT TO MERIT A
BLANKET VARIABLE DESIGNATION FOR SAKE OF SIMPLICITY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...NIELD
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 MON FEB 16 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 16/09Z TAF UPDATE/...
ISSUED AT 329 AM EST MON FEB 16 2015
MINOR ADJUSTMENTS REQUIRED AS SNOW MAKES ITS WAY NORTHWARD. CONTINUE
TO EXPECT WORST CONDITIONS AT BMG WITH BETTER CONDITIONS FURTHER
NORTH. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1131 PM EST SUN FEB 15 2015
LIGHT SNOW HAS BEEN DEVELOPING TO THE SOUTH OF THE TAF SITES OVER
THE PAST COUPLE OF HOURS. SHOULD START TO SEE SOME VISIBILITY
RESTRICTIONS IN THE KHUF/KBMG OVER THE NEXT FEW HOURS AS LEADING
EDGE OF SNOW AREA DRIFTS NORTH. SHORT TERM MODELS SUGGEST STRONGER
LIFT WILL BE REACHING KHUF/KBMG AROUND 160900Z...SO EXPECTING MORE
WIDESPREAD IFR/LIFR VISIBILITIES IN THOSE AREA AFTER THAT TIME.
THE KIND TERMINAL SHOULD START TO SEE VISIBILITY RESTRICTIONS IN
SNOW DEVELOPING AROUND 161200Z...WITH WIDESPREAD IFR RESTRICTIONS
SHORTLY AFTER THAT BASED ON TIMING OF BEST LIFT. FINER SCALE MODELS
ARE SUGGESTING HEAVIER SNOW/LIFR RESTRICTIONS MAY REACH KIND AS WELL
FOR A PERIOD AFTER SUNRISE MONDAY. CONFIDENCE IS LOWER HERE...SO
WILL KEEP LIFR RESTRICTIONS OUT OF KIND FOR NOW. THESE CONDITIONS
EXPECTED TO CONTINUE BEYOND 161800Z.
APPEARS THAT THE PRECIPITATION SHIELD WILL REMAIN SOUTH OF KLAF
TERMINAL.
SURFACE WINDS GENERALLY 080-110 DEGREES AT 8-11 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...JAS/NIELD
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
243 AM EST MON FEB 16 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS EXPECTED
TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREADING SNOW ACROSS THE
TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF CENTRAL
INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN INDIANA. THE
LOW IS EXPECTED TO REACH THE CAROLINAS TONIGHT...BRINGING AN END TO
SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF THE
WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIEST SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH ACROSS
THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS EVENING...EFFECTIVELY
ENDING LIFT THEN. ISENTROPIC SURFACE SHOW LITTLE IN THE WAY OF LIFT
ACROSS CENTRAL INDIANA...WITH BEST ISENTROPIC LIFT MUCH FARTHER
SOUTH. STILL NOTED IN THE 2-3 G/KG SPECIFIC HUMIDITY THAT IS
AVAILABLE ACROSS SOUTHERN PARTS OF CENTRAL INDIANA. Q VECTOR ALSO
SHOW BEST LIFT AND FORCING WELL SOUTH OF CENTRAL INDIANA...ACROSS
TENNESSEE AND KENTUCKY. MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD
LIFT AND SATURATION THROUGH THE MORNING HOURS...WITH BEST MOISTURE
ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
ISSUED AT 243 AM EST MON FEB 16 2015
EXPECT CONTINUED COLD INTO THE LONG TERM PERIOD WITH A BIT OF A WARM
UP LATE IN THE PERIOD AS UPPER LEVEL FLOW BECOMES A BIT MORE ZONAL.
LOW CHANCES FOR PRECIP...MAINLY SNOW...APPEAR MERITED OVER THE
COMING WEEKEND...BUT IN LIGHT OF THE FAIRLY SIGNFICANT MODEL
DIFFERENCES IN HANDLING THIS PERIOD...SEE LITTLE REASON TO ADJUST
BLENDED INITIALIZATION...WHICH HAS THIS HANDLED RELATIVELY WELL.
&&
.AVIATION /DISCUSSION FOR THE 160600Z TAFS/...
ISSUED AT 1131 PM EST SUN FEB 15 2015
LIGHT SNOW HAS BEEN DEVELOPING TO THE SOUTH OF THE TAF SITES OVER
THE PAST COUPLE OF HOURS. SHOULD START TO SEE SOME VISIBILITY
RESTRICTIONS IN THE KHUF/KBMG OVER THE NEXT FEW HOURS AS LEADING
EDGE OF SNOW AREA DRIFTS NORTH. SHORT TERM MODELS SUGGEST STRONGER
LIFT WILL BE REACHING KHUF/KBMG AROUND 160900Z...SO EXPECTING MORE
WIDESPREAD IFR/LIFR VISIBILITIES IN THOSE AREA AFTER THAT TIME.
THE KIND TERMINAL SHOULD START TO SEE VISIBILITY RESTRICTIONS IN
SNOW DEVELOPING AROUND 161200Z...WITH WIDESPREAD IFR RESTRICTIONS
SHORTLY AFTER THAT BASED ON TIMING OF BEST LIFT. FINER SCALE MODELS
ARE SUGGESTING HEAVIER SNOW/LIFR RESTRICTIONS MAY REACH KIND AS WELL
FOR A PERIOD AFTER SUNRISE MONDAY. CONFIDENCE IS LOWER HERE...SO
WILL KEEP LIFR RESTRICTIONS OUT OF KIND FOR NOW. THESE CONDITIONS
EXPECTED TO CONTINUE BEYOND 161800Z.
APPEARS THAT THE PRECIPITATION SHIELD WILL REMAIN SOUTH OF KLAF
TERMINAL.
SURFACE WINDS GENERALLY 080-110 DEGREES AT 8-11 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...NIELD
AVIATION...JAS
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
224 AM EST MON FEB 16 2015
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 224 AM EST MON FEB 16 2015
A VIGOROUS LOW PRESSURE SYSTEM OVER THE SOUTHERN PLAINS IS
EXPECTED TO PUSH ACROSS THE DEEP SOUTH TODAY...SPREAD SNOW ACROSS
THE TENNESSEE AND OHIO VALLEYS...INCLUDING SOUTHERN PARTS OF
CENTRAL INDIANA. ACCUMULATING SNOW IS EXPECTED ACROSS SOUTHERN
INDIANA. THE LOW IS EXPECTED TO REACH THE CAROLINAS
TONIGHT...BRINGING AN END TO SNOWFALL ACROSS THE AREA TONIGHT.
ANOTHER ARCTIC HIGH PRESSURE SYSTEM IS THEN EXPECTED TO BUILD
ACROSS INDIANA IN THE WAKE OF THE LOW. THIS WILL RESULT IN ANOTHER
SHOT OF VERY COLD AIR TO SWEEP INTO THE INDIANA...PROVIDING DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES. THROUGH THE MIDDLE OF
THE WEEK.
NEXT WEEKEND COULD SEE CHANCES FOR SNOW BUT ALSO A WARMUP AS THE
EAST COAST TROUGH FINALLY ABATES.
&&
.NEAR TERM /TODAY/...
ISSUED AT 224 AM EST MON FEB 16 2015
SURFACE ANALYSIS EARLY THIS MORNING SHOWS ARCTIC HIGH PRESSURE IN
PLACE OVER LOWER MICHIGAN AND A DEVELOPING SURFACE LOW ACROSS
EASTERN TEXAS. A VERY DRY AND COLD EASTERLY SURFACE FLOW WAS IN
PLACE ACROSS CENTRAL INDIANA...AS DEW POINTS WERE BELOW ZERO. THIS
INTRUSION OF DRY LOWER LEVEL AIR WILL BE IMPORTANT IN THIS
FORECAST. SATELLITE SHOWS A WAVE OF CLOUDS OVER MO...IL AND
INDIANA SPREADING EASTWARD. RADAR SHOWS A BAND OF SNOW ACROSS OUR
WARNING AREA IN SOUTHERN CENTRAL INDIANA WHERE SPOTTERS HAVE
REPORTED ABOUT 1/4 INCH OF ACCUMULATION AS OF 100 AM. NOTED ON
RADAR WAS A VERY SHARP CUT OFF SNOW VS NO-SNOW...AND DRY AIR WAS
PLAYING A NOTE. FOR EXAMPLE...DEWPOINTS AT BMG WERE -1. NO SNOW
THERE. DEW POINTS AT VINCENNES...14. SNOWING THERE. A 16 DEGREE
DIFFERENCE. THE VERY COLD TEMPERATURES IN PLACE WILL MAKE FOR
HIGHER SNOW/LIQUID RATIOS...RESULTING IN HIGH SNOW TOTALS IN THE
AREAS THAT GET SNOW.
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT DURING THIS
PERIOD...PUSHING THE SURFACE LOW ACROSS MISSISSIPPI AND
ALABAMA...WHICH IS A MORE FAVORABLE TRACK FOR HEAVIES SNOWS ACROSS
KENTUCKY. ALOFT A QUICK MOVING SHORT WAVE IS EXPECTED TO PUSH
ACROSS THE OHIO VALLEY THIS AFTERNOON AND EXIT THIS
EVENING...EFFECTIVELY ENDING LIFT THEN. ISENTROPIC SURFACE SHOW
LITTLE IN THE WAY OF LIFT ACROSS CENTRAL INDIANA...WITH BEST
ISENTROPIC LIFT MUCH FARTHER SOUTH. STILL NOTED IN THE 2-3 G/KG
SPECIFIC HUMIDITY THAT IS AVAILABLE ACROSS SOUTHERN PARTS OF
CENTRAL INDIANA. Q VECTOR ALSO SHOW BEST LIFT AND FORCING WELL
SOUTH OF CENTRAL INDIANA...ACROSS TENNESSEE AND KENTUCKY.
MEANWHILE TIME HEIGHT SECTIONS SHOW GOOD LIFT AND SATURATION
THROUGH THE MORNING HOURS...WITH BEST MOISTURE ACROSS THE SOUTHERN
PARTS OF THE FORECAST AREA.
FORECAST SOUNDINGS ALSO HINT TOWARD DEEP SATURATION WITH BEST DEEP
MOISTURE IN PLACE ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA
ALONG WITH PRECIPITATABLE WATER AMOUNTS NEAR 0.4 INCHES. ALSO
FAVORABLE FOR SNOW IN THE SOUNDINGS IS THE SATURATION IN THE
DENDRITIC GROWTH ZONE OF -10 TO -20. HRRR SUGGESTS BEST MOISTURE
WILL BE CONTAINED TO THE SOUTHERN PARTS OF THE FORECAST AREA.
FINALLY...NAM ALSO SUGGEST A WEAK TROWAL PUSHING ACROSS SOUTHERN
PARTS OF CENTRAL INDIANA THIS AFTERNOON.
THUS...WILL KEEP THE SNOW AMOUNTS IN PLACE ACROSS THE FAR SOUTHERN
COUNTIES...WITH NEAR 6 INCHES EXPECTED. WITH THE CONTINUE DRY
EASTERLY FLOW...LITTLE TO NO SNOW WILL BE EXPECTED ACROSS THE FAR
NORTHERN PARTS OF THE FORECAST AREA...WITH ONLY 1-2 INCHES OR LESS
ALONG THE I-70 CORRIDOR.
GIVEN ALL OF THIS ONGOING FORECAST HAS A GOOD HANDLE ON
THIS...HOWEVER WILL NOT HESITATE TO UPGRADE THE
SULLIVAN...BLOOMINGTON...AND GREENSBURG AREA TO A WARNING SHOULD
SNOW PILE UP QUICKER THAN EXPECTED. WILL USE 100 POPS SOUTH TO
NEAR 0 NORTH...WITH HIGHS COOLER THAN MAVMOS GIVEN THE COLD
NORTHEASTERLY FLOW.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 224 AM EST MON FEB 16 2015
GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THIS PERIOD AND WILL
USE A BLEND MAIN FORECAST CHALLENGE WILL BE TEMPS.
UPPER SHORT WAVE LOOKS TO DEPART THIS EVENING...AND FORCING ENDS
ACROSS THE AREA AS TIME HEIGHTS BEGIN TO SHOW SUBSIDENCE. FAR
ALOFT A FAVORABLE WAVE OF PV MOVES ACROSS CENTRAL
INDIANA...HOWEVER...ALL THE AVAILABLE MOISTURE WILL BE LONG GONE
TO THE EAST BEFORE THIS FEATURE ARRIVES. FORECAST SOUNDINGS
DRY OUT THROUGH THE NIGHT AS COLD AIR ADVECTION IS EXPECTED TO
RESUME IN THE MID LEVELS. BY 12Z TUES...850MB TEMPS FALL TO -13
AND THAT/S NOT ALL. THE COLD AIR ADVECTION WILL CONTINUE INTO
WEDNESDAY...WHEN 850MB TEMPS FALL TO -25C AND RAW NAM NUMERICAL
DATA SPITS OUT A 494 THICKNESS. ALOFT...BROAD CYCLONIC FLOW IS
EXPECTED TO REMAIN IN PLACE ACROSS THE EASTERN PARTS OF CANADA AND
THE UNITED STATES. THIS WILL ALLOW WHAT SEEMS LIKE AN ENDLESS FLOW
OF COLD AIR INTO THE OHIO VALLEY. WE WILL GET NO HELP AT THE
SURFACE AS SURFACE RIDGING LOOKS TO REMAIN WEST OF INDIANA UNTIL
AT LEAST THURSDAY AND BROAD CYCLONIC FLOW LOOKS TO PERSIST.
FURTHERMORE THE FLOW OFF OF LAKE MICHIGAN MAY RESULT IN SOME LAKE
CLOUDS/FLURRIES FROM TIME TO TIME ACROSS THE NORTHEAST PARTS OF
THE FORECAST AREA. THUS WILL TREND HIGHS COLDER THAN
MAVMOS...ESPECIALLY IN THE AREAS THAT RECEIVE NEW SNOW TODAY. WILL
ALSO TREND LOWS COLDER GIVEN THE STRONG COLD AIR ADVECTION.
SO IN SUMMARY...IT/S GONNA BE COLD...IT/S GONNA BE GRAY...AND IT/S
GONNA LAST UNTIL AT LEAST THURSDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 155 PM EST SUN FEB 15 2015
MAIN FOCUS FOR THE EXTENDED WILL BE ON TIMING OF POPS AS WELL AS
TEMPERATURES.
MODELS ARE HAVING TIMING DIFFERENCES WITH WEAK SURFACE SYSTEM THAT
IS EXPECTED TO IMPACT CENTRAL INDIANA NEXT WEEKEND WITH THE 12Z GEM
BEING THE FASTEST...00Z ECMWF THE MIDDLE GROUND AND 12Z GFS THE
FASTEST. THESE DIFFERENCES RESULT FROM FAST NORTHWEST FLOW ALOFT
OVER THE AREA IN BETWEEN THE PERSISTENT WESTERN RIDGE AND
NORTHEASTERN TROUGH. WITH THESE KIND OF DIFFERENCES...PREFER TO PLAY
IT SAFE AND NOT ROCK THE BOAT AND KEEP CHANCE POPS FROM FRIDAY NIGHT
THROUGH SUNDAY. 00Z ECMWF THERMAL PROFILE PROGS SUGGEST SOME RAIN
COULD MIX IN WITH THE SNOW...ESPECIALLY ACROSS OUR SOUTHERN
COUNTIES...HOWEVER THE COLDER 12Z GFS KEEPS IT ALL SNOW. WITH DECENT
SOUTHERLY FLOW ON THE BACK OF THE DEPARTING ARCTIC HIGH...COULD SEE
A MIX. HOWEVER...WILL KEEP IT ALL SNOW FOR NOW UNTIL OR IF THE
EXTENDED MODELS CONTINUE TO TREND WARMER.
LOW LEVEL THERMAL PROGS SUGGEST LATE WEEKEND WARMUP IN THE WAKE OF
THE ARCTIC HIGH. REGIONAL BLEND APPEARS TO BE HANDLING THIS WEEK
WITH TEMPERATURES GETTING CLOSER TO NORMAL BY SATURDAY.
&&
.AVIATION /DISCUSSION FOR THE 160600Z TAFS/...
ISSUED AT 1131 PM EST SUN FEB 15 2015
LIGHT SNOW HAS BEEN DEVELOPING TO THE SOUTH OF THE TAF SITES OVER
THE PAST COUPLE OF HOURS. SHOULD START TO SEE SOME VISIBILITY
RESTRICTIONS IN THE KHUF/KBMG OVER THE NEXT FEW HOURS AS LEADING
EDGE OF SNOW AREA DRIFTS NORTH. SHORT TERM MODELS SUGGEST STRONGER
LIFT WILL BE REACHING KHUF/KBMG AROUND 160900Z...SO EXPECTING MORE
WIDESPREAD IFR/LIFR VISIBILITIES IN THOSE AREA AFTER THAT TIME.
THE KIND TERMINAL SHOULD START TO SEE VISIBILITY RESTRICTIONS IN
SNOW DEVELOPING AROUND 161200Z...WITH WIDESPREAD IFR RESTRICTIONS
SHORTLY AFTER THAT BASED ON TIMING OF BEST LIFT. FINER SCALE MODELS
ARE SUGGESTING HEAVIER SNOW/LIFR RESTRICTIONS MAY REACH KIND AS WELL
FOR A PERIOD AFTER SUNRISE MONDAY. CONFIDENCE IS LOWER HERE...SO
WILL KEEP LIFR RESTRICTIONS OUT OF KIND FOR NOW. THESE CONDITIONS
EXPECTED TO CONTINUE BEYOND 161800Z.
APPEARS THAT THE PRECIPITATION SHIELD WILL REMAIN SOUTH OF KLAF
TERMINAL.
SURFACE WINDS GENERALLY 080-110 DEGREES AT 8-11 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR INZ067>072.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
INZ060>065.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...PUMA
SHORT TERM...PUMA
LONG TERM...MK
AVIATION...JAS
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AREA FORECAST DISCUSSION
NWS GOODLAND KS
208 PM MST MON FEB 16 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 208 PM MST MON FEB 16 2015
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS BROAD TROUGH
ACROSS THE EASTERN US WITH SHORTWAVE ALONG BASE OF TROUGH OVER
COLORADO. AT THE SURFACE LOW PRESSURE REMAINS IN PLACE OVER NORTH
CENTRAL KANSAS...WITH HIGH PRESSURE ACROSS THE NORTHERN ROCKIES
EXTENDING SOUTH TOWARDS NORTHERN COLORADO.
STEEP LOW LEVEL LAPSE RATES AND WEAK INSTABILITY HAVE LED TO
RAIN/SNOW SHOWER DEVELOPMENT THIS AFTERNOON ACROSS THE CWA.
GRAUPEL HAS BEEN OBSERVED WITH SOME OF THIS ACTIVITY. THIS
ACTIVITY WILL MAINLY BE TIED TO DAYTIME HEATING...QUICKLY ENDING
AS LOW LEVELS STABILIZE NEAR SUNSET. THERE WILL BE SOME WEAK
FORCING AROUND THE REGION OVERNIGHT...HOWEVER OTHER THAN MAYBE A
FEW FLURRIES IT DOESNT APPEAR TO BE SUPPORTIVE OF MEASURABLE
PRECIP.
BETTER FORCING IS PROGGED TO MOVE THROUGH THE REGION BY 12Z
TUESDAY AS POSITIVE MID LEVEL VORTICITY ASSOCIATED WITH SHORTWAVE
TROUGH ROTATES INTO THE REGION. THIS WILL RESULT IN SHOWER
REDEVELOPMENT FROM THE NORTH TO THE SOUTH...INCREASING IN COVERAGE
AS LAPSE RATES STEEPEN WITH DAYTIME HEATING. I COULD SEE A
RAIN/SNOW/ICE PELLET MIX AGAIN LIKE TODAY...WITH MINIMAL TO NO
ACCUMULATIONS. UNIDIRECTIONAL GRADIENT AND WINDS ALOFT INCREASE
DURING THE DAY...AND IF WE WERE TO MIX TO 700MB WE COULD SEE
WARNING CRITERIA WINDS MIX TO THE SURFACE. MIXING HEIGHTS APPEAR
TO BE LIMITED DUE TO INCREASING CLOUD COVER...THOUGH THERMAL
PROFILES IN CLEAR SKIES COULD SUPPORT MUCH DEEPER MIXING. FOR NOW
I KEPT GUSTS 45-50MPH. THERE IS A CONCERN THAT SHOWERS COULD HELP
MIX STRONGER WINDS TO THE SURFACE. WINDS COULD ALSO COMBINE WITH
SHOWERS TO REDUCE VISIBILITIES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 141 PM MST MON FEB 16 2015
WITH THE PASSAGE OF THE SHORTWAVE THRU THE CWA ON TUESDAY...THE TRI
STATE REGION WILL TREND INTO A DRY PERIOD FROM TUESDAY NIGHT RIGHT
INTO 12Z FRIDAY. DURING THIS TIMEFRAME...H5 RIDGE WILL FLATTEN SOME
OVER THE WESTERN PORTION OF THE COUNTRY...ALLOWING FOR WNW FLOW OVER
THE AREA. AT THE SURFACE...HIGH PRESSURE SLIDES SOUTH FROM CANADA
SHIFTING EAST THRU THE WEEK...AND A LEE-SIDE TROUGH SETS UP OVER THE
EASTERN SIDE OF THE ROCKIES. INCREASING WAA WILL RESULT AS SOUTHERLY
FLOW TAPS INTO WARMER AIR. FROM FRIDAY ON THRU NEXT MONDAY...
SHORTWAVE WILL PINWHEEL AROUND BROAD UPPER LOW TO THE EAST...SETTING
UP OVER THE ROCKIES. BLOCKING PATTERN OFF THE WEST COAST...AS WELL
AS OVER THE CENTRAL ATLANTIC OCEAN...KEEPS UPPER TROUGH OVER THE
ROCKIES. THIS SYSTEM WILL BE ABLE TO TAP INTO PACIFIC MOISTURE...
FEEDING IT INTO THE REGION FOR THE PERIOD. AT THE SURFACE HIGH
PRESSURE AGAIN BUILDING DOWN FROM CENTRAL CANADA WILL PROVIDE AN
EASTERLY/UPSLOPE FETCH INTO THE REGION. THE RESULT WILL BE CHANCE
POPS FOR -SW THRU THE ENTIRE FRIDAY THRU MONDAY TIMEFRAME WITH LIGHT
SCATTERED AMOUNTS. A WAA TREND FOR THE FIRST HALF OF THE EXTENDED
WILL GIVE WAY TO BELOW NORMAL NUMBERS WITH THE ARRIVAL OF THE COLD
CANADIAN RIDGE. OVERALL HIGHS WILL RANGE FROM THE 40S WEDNESDAY UP
TO NEAR 60F FOR THURS/FRI...THEN DROP DOWN INTO THE 20S TO L30S FOR
THE WEEKEND INTO NEXT MONDAY. OVERNIGHT LOWS WILL SEE BIG DROP AT
THE END OF THE WEEK WITH CANADIAN RIDGE OVER AREA. LOWS WILL RANGE
FROM THE TEENS AND MID 20S THRU FRIDAY NIGHT...THEN DOWN TO THE
TEENS AND SINGLE NUMBERS OVER THE UPCOMING WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 1058 AM MST MON FEB 16 2015
VFR CONDITIONS SHOULD PREVAIL THROUGH TAF PERIOD. TEMPORARY MVFR
POSSIBLY IFR COULD STILL OCCUR THIS AFTERNOON AND AGAIN TUESDAY AS
SHOW SHOWERS DEVELOP AND MOVE ACROSS THE REGION. LIGHT FOG AND
LOW STRATUS MAY ALSO DEVELOP...HOWEVER GUIDANCE MIGHT BE BIASED
FROM SNOW PACK AND IM NOT PARTICULARLY CONFIDENT IN THIS. I ADDED
MVFR CIG CROUP WAS ADDED AT KMCK AS GUIDANCE IS SHOWING 1500 KFT
AGL CLOUD DECK MOVING OVER THE TERMINAL TUESDAY MORNING. STRONGER
WINDS ARE EXPECTED LATE IN THE TAF PERIOD DEVELOPING FROM THE
WEST TO THE EAST. RESULT WILL BE GUSTS AROUND 35 KT AT KGLD...WITH
HIGHER WINDS OUTSIDE THE TAF PERIOD AT KMCK. AFTERNOON WINDS COULD
BE STRONGER THAT THIS AT BOTH TERMINALS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JN
AVIATION...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1122 AM CST MON FEB 16 2015
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 1027 AM CST MON FEB 16 2015
WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
SHORTWAVE TROUGH DROPPING SOUTHWARD ACROSS THE GREAT BASIN REGION.
MEANWHILE, A WESTERLY FLOW ALOFT PREVAILS ACROSS THE WESTERN HIGH
PLAINS. NEAR THE SURFACE, A BROAD AREA OF ARCTIC HIGH PRESSURE HAS
SETTLED ACROSS THE CENTRAL AND WESTERN HIGH PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1120 AM CST MON FEB 16 2015
PREDOMINATELY VFR CONDITIONS ARE EXPECTED TO PREVAIL AT
ALL TAF SITES THROUGH EARLY TUESDAY MORNING. LIGHT NORTHWESTERLY
WINDS WILL PERSIST THROUGH THE PERIOD AS A BROAD AREA OF HIGH
PRESSURE MOVES FURTHER EAST ACROSS THE CENTRAL PLAINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 22 41 19 / 10 10 10 0
GCK 42 20 41 18 / 10 10 10 0
EHA 39 23 42 22 / 10 10 10 0
LBL 40 20 43 20 / 10 10 10 0
HYS 42 22 35 17 / 10 20 20 10
P28 40 23 41 19 / 30 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1028 AM CST MON FEB 16 2015
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 1027 AM CST MON FEB 16 2015
WV IMAGERY AND 12Z UPPER AIR ANALYSIS INDICATE AN UPPER LEVEL
SHORTWAVE TROUGH DROPPING SOUTHWARD ACROSS THE GREAT BASIN REGION.
MEANWHILE, A WESTERLY FLOW ALOFT PREVAILS ACROSS THE WESTERN HIGH
PLAINS. NEAR THE SURFACE, A BROAD AREA OF ARCTIC HIGH PRESSURE HAS
SETTLED ACROSS THE CENTRAL AND WESTERN HIGH PLAINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 500 AM CST MON FEB 16 2015
THE SNOW BAND HAS ALREADY MOVED SOUTHEAST OF THE TERMINALS AND CONDITIONS
ARE VFR NOW. EXPECT VFR TO CONTINUE FOR THE REST OF THE TAF PD. WINDS
WILL BE NORTHWESTERLY TO NORTHERLY AT 5 TO 10 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 22 41 19 / 10 10 10 0
GCK 42 21 41 18 / 10 10 10 0
EHA 39 23 42 22 / 10 10 10 0
LBL 40 21 43 20 / 10 10 10 0
HYS 42 22 35 17 / 10 20 20 10
P28 40 23 41 19 / 30 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
407 AM MST MON FEB 16 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 404 AM MST MON FEB 16 2015
FORECAST CONCERNS WILL BE HIGH TEMPERATURES THROUGH THE PERIOD...CHANCE
OF PRECIPITATION INTO TUESDAY...AND WINDS ON TUESDAY. SATELLITE SHOWING
AN AMPLIFIED PATTERN FROM THE PACIFIC INTO THE WESTERN ATLANTIC. THIS
PATTERN CONSISTS OF A LARGE AND COMPLEX TROUGH OVER MOST OF THE PACIFIC
TO A HIGHLY AMPLIFIED RIDGE ALONG THE WEST COAST OF NORTH AMERICA THEN
TO A BROAD TROUGH OVER THE EASTERN TWO THIRDS OF THE COUNTRY.
NUMEROUS SHORTWAVE TROUGHS WITHIN THIS FLOW. ONE SHORTWAVE THAT
BROUGHT SNOW TO THE AREA HAS MOVED SOUTH AND EAST. ANOTHER
SHORTWAVE TROUGH IS APPROACHING BEHIND THIS TROUGH. AT JET
LEVEL...MODELS STARTED OUT FINE. AT MID LEVELS...THE CANADIAN...
UKMET AND GFS WERE DOING A LITTLE BETTER THAN THE OTHER OUTPUT.
THE SREF WAS DOING THE BEST SO FAR ON THE SURFACE WIND AND
PRESSURE PATTERN. THE ECMWF...GFS...NAM AND CANADIAN WERE DOING
BEST ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...CURRENTLY THERE IS AN AREA OF FOG ENTERING THE
NORTHWEST PORTION OF THE FORECAST AREA. THE SMALL SCALE
GUIDANCE...ESPECIALLY THE HRRR...CATCHES ONTO THIS AND BRINGS AN
AREA OF FOG INTO MOST OF THE WESTERN HALF OF THE AREA THROUGH MID
MORNING. SOME INDICATIONS THAT IT COULD BE DENSE. SO EXPANDED THE
FOG AREA THAT THE EVENING SHIFT PUT INTO THE GRIDS. THIS WILL NEED
TO BE WATCHED CLOSELY.
MAIN JET ENERGY STAYS WELL WEST AND SOUTH OF THE AREA THROUGH THIS
PERIOD. NEW MODEL GUIDANCE HAS TAKEN THE NEXT SHORTWAVE...WHICH
HAS BEEN ADVERTISED FOR A FEW DAYS...FURTHER WEST WHICH HAS ALSO
BEEN THE TREND RECENTLY. BASED ON THE HEIGHT FALLS AND LATEST
RADAR...THIS LOOKS REASONABLE. PRECIPITATION TO THE WEST OF AREA
AT THIS TIME LOOKS TO BRUSH THE FAR WESTERN PORTION OF CHEYENNE
AND KIT CARSON COUNTIES. ONLY MADE MODIFICATIONS TO THE EVENING
SHIFTS DEPICTION OF THIS.
A SECONDARY SHORTWAVE APPROACHES FROM THE NORTH LATE THIS MORNING
AND EARLY THIS AFTERNOON. THETA-E LAPSE RATES AND THE TQ INDEX
WOULD INDICATE THAT THE AIR MASS HAS SOME INSTABILITY AND WILL BE
SUSCEPTIBLE TO THE LIFT THAT WILL BE PRESENT. THIS MATCHES WELL
WITH THE LIGHT QPF GENERATED BY THE MODEL OUTPUT. SO PUT IN SLIGHT
CHANCE TO LOW CHANCE POPS TO CAPTURE THIS. THIS AREA OF PRECIPITATION
ENDS DURING THE EVENING. FAVORABLE THETA-E LAPSE RATES AND WEAK
LIFT REMAIN THROUGH THE NIGHT WITH NOT AS MUCH MOISTURE. SO
INSERTED FLURRIES INTO THE FORECAST AFTER MIDNIGHT.
COMBINATION OF CLOUD COVER AND PRECIPITATION WILL KEEP HIGH TEMPERATURES
ON THE COLD SIDE...BUT WARMER THAN YESTERDAY. SO WENT TOWARD THE COOLER
AND BETTER RECENT PERFORMING GUIDANCE.
TUESDAY/TUESDAY NIGHT...VERY STRONG NORTH TO SOUTH JET MOVES TOWARD
THE AREA DURING THE DAY. MODELS ARE IN MUCH BETTER AGREEMENT AS TO
THIS JETS POSITION THAN THE PREVIOUS FEW DAYS. HOWEVER THE
CANADIAN STILL REMAINS THE FURTHEST WEST. LEFT FRONT QUADRANT OF
THE JET APPROACHES THE WESTERN PORTION OF THE AREA BY LATE
MORNING. THIS JET LEFT FRONT QUADRANT LOOKS TO AFFECT THE ENTIRE
AREA IN THE AFTERNOON.
THETA-E LAPSE RATES AND THE TQ INDEX INDICATE INSTABILITY REMAINS
ALOFT AND THE AIR MASS WILL BE SUSCEPTIBLE TO THE LIFT COMING.
WITH THE STRONG JET AFFECTING THE AREA...PUT IN SLIGHT CHANCE TO
LOW CHANCE POPS TO ACCOUNT FOR THIS.
IT STILL LOOKS LIKE A WINDY DAY. THE QUESTION IS HOW MUCH. LAPSE
RATES THROUGH 700 MB LOOK GOOD WITH LESS FAVORABLE LAPSE RATES
ABOVE THIS. DOWNWARD MOTION IS NOT THAT STRONG PLUS LOOK TO HAVE
CLOUD COVER AS WELL. WILD CARD IN THIS IS THE PRECIPITATION THAT
COULD MIX DOWN THE HIGHER WINDS. MOST MODEL OUTPUT HAS NEAR 40
KNOTS THAT WILL BE MIXED DOWN. HOWEVER...A COUPLE OF THE MODELS
ARE SHOWING WINDS NEAR 50 KNOTS. RIGHT NOW IT LOOKS LIKE WE COULD
GUST TO AROUND 50 MPH. AGAIN THE DAY SHIFT WILL HAVE TO TAKE A
CLOSE LOOK AT THIS.
IT LOOKS LIKE A COLD SURGE MOVES IN EARLY IN THE MORNING. THAT
COMBINED WITH A LOT OF CLOUD COVER THROUGH THE MIDDLE OF THE DAY
WILL MAKE FOR A COLDER DAY. SO TRENDED AGAIN TOWARD THE COOLER AND
RECENT BETTER PERFORMING GUIDANCE IN THIS SCENARIO.
UPPER JET/LEFT FRONT QUADRANT MOVES INTO THE EASTERN PORTION OF
THE AREA BY LATE EVENING AND NEAR THE EASTERN EDGE OR JUST OF THE
AREA BY LATE IN THE NIGHT. RIGHT NOW WILL NOT HAVE MENTION OF ANY
PRECIPITATION BUT WOULD NOT BE SURPRISED THAT SOME FLURRY ACTION
COULD CONTINUE INTO THE EARLY EVENING.
WINDS LOOK LIGHT FOR MOST OF THE NIGHT WITH NOT A LOT OF CLOUD
COVER TO START OUT. MODELS DO INCREASE THE CLOUD COVER IN THE LAST
HALF OF THE NIGHT PROBABLY BECAUSE OF THE JET. THINK WE WILL
PROBABLY DROP QUICKLY BEFORE CLOUD COVER STOPS THE FALL. WENT
COOLER BUT NOT AS COOL AS I COULD HAVE GONE.
WEDNESDAY/WEDNESDAY NIGHT...UPPER JET MOVES EAST OF THE AREA
DURING THE DAY. MODELS DEVELOP A LOT OF MID AND HIGH LEVEL CLOUD
COVER OVER THE AREA INTO THE AFTERNOON. THIS CLOUD COVER HANGS ON
THE LONGEST IN THE EASTERN PORTION OF THE AREA. THERE COULD END UP
BEING QUITE THE GRADIENT. AIR MASS DOES WARM UP. AT THIS TIME WILL
HAVE THE WESTERN PORTION WARMER THAN THE EASTERN PORTION.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 315 AM MST MON FEB 16 2015
APOLOGIZE FOR LATENESS ON THIS LONG TERM AFD...MUCH COLLABORATION
AND GRID EDITING WAS NEEDED FROM THE CR INITIALIZATION PROCEDURE.
FORECAST GUIDANCE AND ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT
FOR THIS EXTENDED FORECAST RUN. HOWEVER...MAJOR CONCERNS REMAIN...
ESPECIALLY FOR POTENTIAL PRECIPITATION OUTCOMES. OVERALL...COLD
TEMPERATURES ARE ASSURED BUT TIMING AND PLACEMENT OF PRECIPITATION
REMAINS A MAJOR QUESTION MARK.
BEGINNING WITH THURSDAY...WARMEST DAY OF THE PERIOD IS FORECAST.
THIS IS DUE TO BRIEF UPPER LEVEL RIDGING...EMPHASIS ON BRIEF. THIS
ALLOWS SOUTHWEST WINDS ALOFT AND A WARM AIR SURGE EAST FROM THE
COLORADO FRONT RANGE. FRIDAY`S TEMPERATURE FORECAST IS COMPLICATED
AS THERE COULD BE RESIDUAL WARMTH. HOWEVER...A LEE CYCLONE MAY
DEVELOP AND WITH COLD AIR SLIDING SOUTH...CYCLONE MAY AID AN EARLIER
COLD AIR ARRIVAL. MAJOR TEMPERATURE BUST POTENTIAL FRIDAY AS THERE
COULD BE PREFRONTAL MIXING INTO WARMER AIR ALOFT OR THE CYCLONE
PULLING COLD AIR IN FASTER. NOT SURE WHICH SOLUTION WINS SO HAVE
LEFT FRIDAYS TEMPERATURES LARGELY UNTOUCHED. NO PRECIPITATION IS
FORECAST THROUGH FRIDAY.
MAJOR CHANGES ARRIVE FRIDAY NIGHT...LASTING INTO AT LEAST NEXT WEEK.
ACCORDING TO OPERATIONAL RUNS AND ENSEMBLES...LARGE TROUGH OF LOW
PRESSURE DEVELOPS IN NORTHWEST FLOW REGIME...PERSISTING OVER THE
WESTERN UNITED STATES. ADDITIONALLY...LARGE RIDGE OF HIGH PRESSURE
BUILDS OVER THE PACIFIC...EXTENDING NORTH TO CANADA AND ALASKA. THIS
PATTERN IS HIGHLY FAVORABLE FOR ANOTHER ARCTIC OUTBREAK. MODELS ARE
LATCHING ON...INDICATING THE ARCTIC SURFACE HIGH SLIDING SOUTH BY
SATURDAY. LATEST WPC GUIDANCE FORECASTS THE SAME SCENARIO. LARGE
DIFFERENCES REMAIN WITH RESPECT TO SURFACE HIGH STRENGTH AND HOW
COLD WE DROP. GFS BRINGS A 1044 MB HIGH WITH MAX/MIN TEMPS IN THE
30S/TEENS SATURDAY AND 20S/NEAR 10 SUNDAY...WARMING MONDAY. THE
SCARIER SOLUTION IS WHAT ECMWF AND GEFS ENSEMBLE MEAN SUGGEST...A
STRONG ARCTIC HIGH SLIDING SOUTH AND STALLING OVER THE HIGH PLAINS
THROUGH MID-WEEK. ECMWF INDICATES A 1058 MB SURFACE HIGH WHILE THE
GEFS ENSEMBLE MEAN BROADCASTS A 1045+ HIGH. ECMWF AND GEFS ENSEMBLE
MEAN DO NOT ADVANCE THE SURFACE HIGH EAST TO THE GREAT LAKES LIKE
THE OPERATIONAL GFS DOES. AS FOR ECE TEMPERATURES...FORECAST CALLS
FOR MAX/MIN TEMPS SATURDAY IN THE 30S/SINGLE DIGITS AND SUNDAY IN
THE TEENS/NEAR 0. MONDAY WARMS TO THE LOW 20S ACCORDING TO EUROPEAN
GUIDANCE...MUCH COOLER THAN THE OPERATIONAL GFS. NEEDLESS TO SAY...
IT WILL BE QUITE COLD/BELOW NORMAL THIS COMING WEEKEND INTO NEXT
WEEK. THIS PATTERN HAS BEEN DEPICTED BY GUIDANCE FOR SEVERAL RUNS SO
CONFIDENCE IN COLDER TEMPERATURES IS HIGH. LATEST SUPERBLEND LOWERED
TEMPERATURES AND IN COLLABORATION WITH NEIGHBORING OFFICES...FURTHER
DOWNWARD ADJUSTMENTS WERE MADE.
NOW...PRECIPITATION CHANCES. GUIDANCE DISAGREEMENT REMAINS FAIRLY
HIGH WITH RESPECT TO SHORTWAVE TROUGHS/UPPER LEVEL DISTURBANCES FOR
ONE TO FEEL CONFIDENT IN PINPOINTING PRECIP CHANCES. MOST GUIDANCE
INDICATES A STRONG PRECIPITATION SIGNAL FRIDAY NIGHT THROUGH
SATURDAY NIGHT IN ASSOCIATION WITH A STRONG SHORTWAVE MOVING IN.
SUPERBLEND INCREASED POPS TO 40 PERCENT FOR THESE DAYS AND SEE NO
REASON TO DEVIATE. SUNDAY AND BEYOND...AM CONCERNED THAT THE ARCTIC
SURFACE HIGH SLIDING SOUTH COULD CONFINE PRECIPITATION ALONG THE
COLORADO FRONT RANGE WITH COLD BUT DRY CONDITIONS FOR THE HIGH
PLAINS. GLANCING AT SOUNDINGS...VERY COLD TEMPERATURES LEAD TO A
VERY LOW DENDRITIC GROWTH LAYER SO IT WOULD BE EASY FOR PRECIP
DEVELOPMENT IN THAT AIR MASS. FOR NOW...LOWERED POPS DUE TO LOW
CONFIDENCE IN THE EVOLUTION OF ANY PRECIPITATION PRODUCING SYSTEM
BEYOND SATURDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1000 PM MST SUN FEB 15 2015
KGLD...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHWEST WINDS
UNDER 10KTS AT TAF ISSUANCE EXPECTED TO CONTINUE THROUGH 19Z
BEFORE INCREASING TO 12KTS FROM 20Z-23Z. AFTER 23Z WINDS SLOWLY
BACK TO THE WEST-SOUTHWEST NEAR 10KTS. CLOUDINESS PRIMARILY MID
AND UPPER LEVELS. WILL HAVE TO WATCH FOR SOME MVFR CLOUDINESS FROM
TAF ISSUANCE THROUGH 15Z PER NAM AND LESSER EXTENT RUC MOISTURE
CROSS-SECTIONS. MODELS ALSO RATHER PERSISTENT IN PRODUCING SOME
FOG/MIST DURING THE SAME TIME PERIOD. WITH KITR RECENTLY DROPPING
TO IFR CIGS WILL BEGIN THE PERIOD WITH A TEMPO GROUP FOR IFR CIGS.
KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT/VARIABLE
WINDS AT TAF ISSUANCE EXPECTED TO BECOME NORTHWEST AROUND 6KTS BY
09Z THEN 13KTS FROM 20Z-22Z BEFORE DECREASING TO 10KTS BY 23Z.
WEST-NORTHWEST WINDS AROUND 7KTS EXPECTED AFTER 05Z. CLOUDINESS
CONFINED TO MID AND UPPER LEVELS THROUGH 19Z BEFORE DECREASING BUT
REMAINING VFR FOR THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...RRH
AVIATION...99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
500 AM CST MON FEB 16 2015
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 500 AM CST MON FEB 16 2015
THE SNOW BAND HAS ALREADY MOVED SOUTHEAST OF THE TERMINALS AND CONDITIONS
ARE VFR NOW. EXPECT VFR TO CONTINUE FOR THE REST OF THE TAF PD. WINDS
WILL BE NORTHWESTERLY TO NORTHERLY AT 5 TO 10 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 22 41 19 / 50 10 10 0
GCK 38 21 41 18 / 10 10 10 0
EHA 38 23 42 22 / 10 10 10 0
LBL 38 21 43 20 / 20 10 10 0
HYS 39 22 35 17 / 10 20 30 10
P28 37 23 41 19 / 100 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
316 AM MST MON FEB 16 2015
.UPDATE...
ISSUED AT 1000 PM MST SUN FEB 15 2015
PRECIPITATION QUICKLY COMING TO AN END FROM NORTH TO SOUTH THIS
EVENING AS MUCH DRIER AIR MOVES IN. FORECAST AREA SHOULD BE CLEAR
OF PRECIP A FEW HOURS AFTER MIDNIGHT. PER MODEL BOUNDARY LAYER RH
AND VISIBILITY FORECASTS HAVE ADDED PATCHY FREEZING FOG TO THE
WESTERN 1/2 OF THE AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 211 PM MST SUN FEB 15 2015
MAIN FOCUS IN THE SHORT TERM CONTINUES TO BE ON SNOW POTENTIAL THIS
AFTERNOON THROUGH MONDAY AS SHORTWAVE TROUGH CURRENTLY OVER WESTERN
COLORADO/NORTHERN NEW MEXICO SLOWLY EJECTS ACROSS THE PLAINS.
MOST 12Z GUIDANCE (NAM/GFS) AND LATEST SHORT RANGE GUIDANCE
(RAP/HRRR) SEEM TO HAVE BETTER HANDLE ON LOCATION/TIMING OF CURRENT
PRECIP OVER COLORADO/WESTERN NEBRASKA AND HAVE SLOWED DOWN ONSET
OVER OUR CWA. WHILE THERE IS WEAK FORCING PRESENT AND LIGHT RETURNS
ON RADAR OVER OUR NORTHERN CWA...THIS HAS STRUGGLED TO OVERCOME A
1500-2000 KFT SUB CLOUD DRY LAYER WITH AVERAGE TD DEPRESSIONS 15-
20F. AS SHORTWAVE FINAL BEGINS TO EJECT EASTWARD STRONGER FORCING
AND BETTER LOW LEVEL MOISTURE RETURN WILL ALLOW FOR INCREASE IN SNOW
COVERAGE FROM THE WEST TO THE EAST. I COULD STILL SEE SOME SNOW
BEFORE THIS...BUT HIGHER CONFIDENCE IS FOR AFTER 00Z. LOOKS LIKE WE
SHOULD HAVE A BAND FORM OVER EASTERN COLORADO AND MOVE TOWARDS THE
I70 CORRIDOR BEFORE SLIDING SOUTH AROUND MIDNIGHT. GUIDANCE IS STILL
SHOWING SOME WEAK FORCING IN THE WEST AND LIGHT PRECIP SIGNAL. NOT A
LOT OF CONFIDENCE IN THIS AS WE APPEAR TO BE ON SUBSIDENT SIDE OF H3
JET. MODELS ARE STILL SHOWING SOME WEAK MID LEVEL VORTICITY AND A
LIGHT PRECIP SIGNAL IN THE WEST...SO I KEPT SLIGHT CHANCE/CHANCE IN
PLACE FOR NOW. BASED ON CURRENT TIMING AND HIGHEST CONFIDENCE IS
APPEARS WE COULD SEE A QUICK INCH (MAYBE A LITTLE MORE) WITH THE
SNOW THIS EVENING...WITH HRRR/RAP POSSIBLY SUPPORTING RATES OF 0.5"
PER HOUR. THE PROGRESSIVE NATURE OF THE BAND WILL BE THE LIMITING
FACTOR ON AMOUNTS...WHERE IF IT LINGERS COULD RESULT IN ISOLATED 2-
3" TOTALS. OTHERWISE I WOULD ONLY ANTICIPATE A DUSTING OF ADDITIONAL
SNOW AFTER MIDNIGHT THROUGH MONDAY IF THERE IS ANY SNOW LINGERING AT
THAT POINT. NOT ANTICIPATING ADVISORY LEVEL SNOWS AT THIS
POINT...AND THREAT FOR THAT SEEMS TO BE VERY NARROW/ISOLATED IN OUR
SW.
WHILE THERE WILL BE A SLIGHT INCREASE IN WINDS DURING THE DAY MONDAY
(10-15 MPH GUSTING 20 MPH) THIS LIKELY WONT BE ENOUGH TO CAUSE
MAJOR DRIFTING OR VISIBILITY REDUCTIONS ON ITS OWN. HIGH TEMPS WILL
BE TRICKY WITH A SLIGHT MODERATION OF TEMPS ALOFT MONDAY...FIGHTING
LIMITED DIURNAL HEATING DUE TO CLOUD COVER. BEST CHANCE FOR BREAKS
IN SKY COVER WILL BE IN THE NORTHEAST...WHERE IF THEY DO SEE SOME
SUNSHINE COULD REACH THE LOWER 40S. IF STRATUS LINGER...MOST WONT
SEE HIGHS OUT OF THE 30S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 315 AM MST MON FEB 16 2015
APOLOGIZE FOR LATENESS ON THIS LONG TERM AFD...MUCH COLLABORATION
AND GRID EDITING WAS NEEDED FROM THE CR INITIALIZATION PROCEDURE.
FORECAST GUIDANCE AND ENSEMBLES HAVE COME INTO MUCH BETTER AGREEMENT
FOR THIS EXTENDED FORECAST RUN. HOWEVER...MAJOR CONCERNS REMAIN...
ESPECIALLY FOR POTENTIAL PRECIPITATION OUTCOMES. OVERALL...COLD
TEMPERATURES ARE ASSURED BUT TIMING AND PLACEMENT OF PRECIPITATION
REMAINS A MAJOR QUESTION MARK.
BEGINNING WITH THURSDAY...WARMEST DAY OF THE PERIOD IS FORECAST.
THIS IS DUE TO BRIEF UPPER LEVEL RIDGING...EMPHASIS ON BRIEF. THIS
ALLOWS SOUTHWEST WINDS ALOFT AND A WARM AIR SURGE EAST FROM THE
COLORADO FRONT RANGE. FRIDAY`S TEMPERATURE FORECAST IS COMPLICATED
AS THERE COULD BE RESIDUAL WARMTH. HOWEVER...A LEE CYCLONE MAY
DEVELOP AND WITH COLD AIR SLIDING SOUTH...CYCLONE MAY AID AN EARLIER
COLD AIR ARRIVAL. MAJOR TEMPERATURE BUST POTENTIAL FRIDAY AS THERE
COULD BE PREFRONTAL MIXING INTO WARMER AIR ALOFT OR THE CYCLONE
PULLING COLD AIR IN FASTER. NOT SURE WHICH SOLUTION WINS SO HAVE
LEFT FRIDAYS TEMPERATURES LARGELY UNTOUCHED. NO PRECIPITATION IS
FORECAST THROUGH FRIDAY.
MAJOR CHANGES ARRIVE FRIDAY NIGHT...LASTING INTO AT LEAST NEXT WEEK.
ACCORDING TO OPERATIONAL RUNS AND ENSEMBLES...LARGE TROUGH OF LOW
PRESSURE DEVELOPS IN NORTHWEST FLOW REGIME...PERSISTING OVER THE
WESTERN UNITED STATES. ADDITIONALLY...LARGE RIDGE OF HIGH PRESSURE
BUILDS OVER THE PACIFIC...EXTENDING NORTH TO CANADA AND ALASKA. THIS
PATTERN IS HIGHLY FAVORABLE FOR ANOTHER ARCTIC OUTBREAK. MODELS ARE
LATCHING ON...INDICATING THE ARCTIC SURFACE HIGH SLIDING SOUTH BY
SATURDAY. LATEST WPC GUIDANCE FORECASTS THE SAME SCENARIO. LARGE
DIFFERENCES REMAIN WITH RESPECT TO SURFACE HIGH STRENGTH AND HOW
COLD WE DROP. GFS BRINGS A 1044 MB HIGH WITH MAX/MIN TEMPS IN THE
30S/TEENS SATURDAY AND 20S/NEAR 10 SUNDAY...WARMING MONDAY. THE
SCARIER SOLUTION IS WHAT ECMWF AND GEFS ENSEMBLE MEAN SUGGEST...A
STRONG ARCTIC HIGH SLIDING SOUTH AND STALLING OVER THE HIGH PLAINS
THROUGH MID-WEEK. ECMWF INDICATES A 1058 MB SURFACE HIGH WHILE THE
GEFS ENSEMBLE MEAN BROADCASTS A 1045+ HIGH. ECMWF AND GEFS ENSEMBLE
MEAN DO NOT ADVANCE THE SURFACE HIGH EAST TO THE GREAT LAKES LIKE
THE OPERATIONAL GFS DOES. AS FOR ECE TEMPERATURES...FORECAST CALLS
FOR MAX/MIN TEMPS SATURDAY IN THE 30S/SINGLE DIGITS AND SUNDAY IN
THE TEENS/NEAR 0. MONDAY WARMS TO THE LOW 20S ACCORDING TO EUROPEAN
GUIDANCE...MUCH COOLER THAN THE OPERATIONAL GFS. NEEDLESS TO SAY...
IT WILL BE QUITE COLD/BELOW NORMAL THIS COMING WEEKEND INTO NEXT
WEEK. THIS PATTERN HAS BEEN DEPICTED BY GUIDANCE FOR SEVERAL RUNS SO
CONFIDENCE IN COLDER TEMPERATURES IS HIGH. LATEST SUPERBLEND LOWERED
TEMPERATURES AND IN COLLABORATION WITH NEIGHBORING OFFICES...FURTHER
DOWNWARD ADJUSTMENTS WERE MADE.
NOW...PRECIPITATION CHANCES. GUIDANCE DISAGREEMENT REMAINS FAIRLY
HIGH WITH RESPECT TO SHORTWAVE TROUGHS/UPPER LEVEL DISTURBANCES FOR
ONE TO FEEL CONFIDENT IN PINPOINTING PRECIP CHANCES. MOST GUIDANCE
INDICATES A STRONG PRECIPITATION SIGNAL FRIDAY NIGHT THROUGH
SATURDAY NIGHT IN ASSOCIATION WITH A STRONG SHORTWAVE MOVING IN.
SUPERBLEND INCREASED POPS TO 40 PERCENT FOR THESE DAYS AND SEE NO
REASON TO DEVIATE. SUNDAY AND BEYOND...AM CONCERNED THAT THE ARCTIC
SURFACE HIGH SLIDING SOUTH COULD CONFINE PRECIPITATION ALONG THE
COLORADO FRONT RANGE WITH COLD BUT DRY CONDITIONS FOR THE HIGH
PLAINS. GLANCING AT SOUNDINGS...VERY COLD TEMPERATURES LEAD TO A
VERY LOW DENDRITIC GROWTH LAYER SO IT WOULD BE EASY FOR PRECIP
DEVELOPMENT IN THAT AIRMASS. FOR NOW...LOWERED POPS DUE TO LOW
CONFIDENCE IN THE EVOLUTION OF ANY PRECIPITATION PRODUCING SYSTEM
BEYOND SATURDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1000 PM MST SUN FEB 15 2015
KGLD...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHWEST WINDS
UNDER 10KTS AT TAF ISSUANCE EXPECTED TO CONTINUE THROUGH 19Z
BEFORE INCREASING TO 12KTS FROM 20Z-23Z. AFTER 23Z WINDS SLOWLY
BACK TO THE WEST-SOUTHWEST NEAR 10KTS. CLOUDINESS PRIMARILY MID
AND UPPER LEVELS. WILL HAVE TO WATCH FOR SOME MVFR CLOUDINESS FROM
TAF ISSUANCE THROUGH 15Z PER NAM AND LESSER EXTENT RUC MOISTURE
CROSS-SECTIONS. MODELS ALSO RATHER PERSISTENT IN PRODUCING SOME
FOG/MIST DURING THE SAME TIME PERIOD. WITH KITR RECENTLY DROPPING
TO IFR CIGS WILL BEGIN THE PERIOD WITH A TEMPO GROUP FOR IFR CIGS.
KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT/VARIABLE
WINDS AT TAF ISSUANCE EXPECTED TO BECOME NORTHWEST AROUND 6KTS BY
09Z THEN 13KTS FROM 20Z-22Z BEFORE DECREASING TO 10KTS BY 23Z.
WEST-NORTHWEST WINDS AROUND 7KTS EXPECTED AFTER 05Z. CLOUDINESS
CONFINED TO MID AND UPPER LEVELS THROUGH 19Z BEFORE DECREASING BUT
REMAINING VFR FOR THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...DR
LONG TERM...RRH
AVIATION...99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
333 AM CST MON FEB 16 2015
...UPDATE TO LONG TERM...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CST MON FEB 16 2015
TUESDAY:
INCREASES POPS NEAR HAYS TUESDAY EVENING AS AN 850-700-HPA WEAK PERTURBATION/BAROCLINIC
ZONE MOVES ACROSS AND COULD PROVIDE THE REGION WITH A SHOWERS/SNOW SHOWERS.
STEEPENING LOW LEVEL LAPSE RATES AND OUTPUT FROM THE ARW CORES AND THE
4 KM NAM GIVE SOME CREDENCE TO THIS. ACTIVITY SHOULD BE FAIRLY LIGHT
IN THE DRY NORTHWESTERLY FLOW ALOFT. TEMPERATURES WILL WARM TO AROUND
40-45F OUTSIDE THIS ACTIVITY ACROSS THE CENTRAL AND SOUTHERN ZONES WITH
COOLER 30S NEAR THE I70 CORRIDOR. OVERNIGHT LOWS WILL BE COLD AND IN
THE UPPER TEENS.
WEDNESDAY:
FAIRLY STRONG NNW FLOW ALOFT WILL CONTINUE ALONG WITH HIGH PRESSURE
ACROSS THE CENTRAL AND NORTHERN PLAINS. THERE WILL BE SOME WEAK LEE
TROUGHING BY WEDNESDAY EVENING AND TEMPERATURES SHOULD MODERATE A FEW
DEGREES - PARTICULARLY ACROSS THE SOUTHWEST ZONES TO MAINLY THE 40S.
NO PRECIPITATION IS EXPECTED.
AND THE REST:
ATTENTION THEN TURNS TO THE WEEKEND. SUPERBLEND STILL HAS CHANCE POPS,
WHICH LOOKS REASONABLE NOW AS THE NEXT WAVE MOVES ACROSS THE CENTRAL
PLAINS. BOTH GFS AND ECMWF SHOW THE CHANCE FOR ACCUMULATING SNOWFALL
WITH THIS NEXT SYSTEM. RIGHT NOW IT IS WAY TOO EARLY TO TELL WHERE AND
HOW MUCH SNOWFALL IS POSSIBLE. ONE THING THAT IS MORE CERTAIN IS MUCH
COOLER TEMPERATURES FOLLOWING A WARM UP. COORDINATED WITH GLD AND TWEAKED
TEMPERATURES SOMEWHAT TO AT LEAST TREND COOLER. TEMPS NOW ARE PROBABLY
WAY TOO WARM AND WILL NEED TO BE ADJUSTED IF THE MODELS CONTINUE AS
ROBUST WITH THIS UPCOMING COLD OUTBREAK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN FEB 15 2015
IFR CEILINGS AND LIFR VISIBILITIES CAN BE EXPECTED WITH A BAND OF
STEADY SNOW WHICH WILL BE CROSSING SOUTHWEST KANSAS THROUGH 12Z
MONDAY. THIS IS BASED ON 04Z SURFACE OBSERVATIONS CURRENTLY IN
THE BAND OF STEADIER SNOWFALL ALONG WITH THE AGREEMENT BETWEEN THE
00Z NAM BUFR SOUNDINGS AND LATEST HRRR. THE NAM AND HRRR ALSO
INDICATED THAT THE BETTER CHANCES FOR THESE LOW IFR/LIFR
CONDITIONS WILL OCCUR AT HYS THROUGH 07Z, GCK BETWEEN 06 AND 08Z,
AND THEN DDC BETWEEN 08Z AND 11Z. OUTSIDE THIS AREA OF STEADY
SNOWFALL MVFR CONDITIONS CAN BE EXPECTED THROUGH LATE MORNING.
AFTER 18Z MONDAY THESE LOW CLOUD ARE FORECAST TO GIVE WAY TO VFR
CONDITIONS AS AN UPPER LEVEL TROUGH THAT WILL BE CROSSES WESTERN
KANSAS. WINDS ACROSS WESTERN KANSAS WILL BE NORTH NORTHWEST AT 10
KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 38 22 41 19 / 20 10 10 0
GCK 38 21 41 18 / 10 10 10 0
EHA 38 23 42 22 / 30 10 10 0
LBL 38 21 43 20 / 20 10 10 0
HYS 39 22 35 17 / 10 20 30 10
P28 37 23 41 19 / 40 10 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
211 AM CST MON FEB 16 2015
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 207 AM CST MON FEB 16 2015
A BAND OF STEADIER SNOWFALL EARLIER THIS MORNING RELATED WELL
WITH A 700MB BAROCLINIC ZONE THAT WAS LOCATED AHEAD OF AN UPPER
LEVEL TROUGH WHICH WAS CROSSING EASTERN COLORADO AS OF 06Z. NAM,
HRRR, AND RAP WERE ALL IN DECENT AGREEMENT WITH THIS BAND OF
STEADIER SNOWFALL CROSSING ALL OF SOUTHWEST AND MOST OF SOUTH
CENTRAL KANSAS BY 12Z MONDAY. SOME LIGHTER SNOWFALL IS STILL
EXPECTED EARLY THIS MORNING SOUTH AND EAST OF A DODGE CITY,
HOWEVER EVEN THIS LIGHT PRECIPITATION IS EXPECTED TO BE ENDING BY
15Z. ADDITIONAL SNOWFALL AMOUNTS EARLY THIS MORNING IN THIS AREA
OF LINGERING SNOWFALL IS EXPECTED TO BE LESS THAN ONE HALF OF AN
INCH. LARGE SCALE SUBSIDENCE IS FORECAST BEHIND THIS UPPER LEVEL
TROUGH AS IT MOVES EAST OF THE AREA EARLY THIS MORNING, HOWEVER
BUFR SOUNDINGS AND EVEN THE HRRR HINT AT SOME LINGERING LOW LEVEL
MOISTURE/STATUS DURING EARLY MORNING HOURS. SOME HIGH LEVEL
MOISTURE/CLOUDS WILL THEN BE POSSIBLE DURING THE AFTERNOON.
CONFIDENCE IS NOT HIGH ON HOW MUCH AFTERNOON CLOUD COVER THERE
WILL BE LATER THIS AFTERNOON, HOWEVER GIVEN THE CURRENT CLOUD
COVER EXPECTED TODAY ALONG WITH THE SNOW THAT FELL DURING THE
OVERNIGHT HOURS WILL UNDERCUT THE COOLER MET GUIDANCE BY SEVERAL
DEGREES. THIS WILL BE CLOSE TO THE PREVIOUS FORECAST FOR HIGHS
TODAY WHICH WILL RANGE FROM THE MID 30S TO NEAR 40.
TONIGHT...CLOUDS WILL BE ON THE INCREASE AS ANOTHER UPPER LEVEL
DISTURBANCE BEGINS TO APPROACH CENTRAL HIGH PLAINS FROM THE
NORTHWEST. A SURFACE BOUNDARY WILL MOVE SOUTH/SOUTHWEST ACROSS
NORTH CENTRAL KANSAS OVERNIGHT WITH SOME INCREASING MOISTURE AND
LIFT DEVELOPING NORTH OF THIS BOUNDARY. THIS MAY GIVE RISE TO A
FEW FLURRIES TOWARDS DAYBREAK. AT THIS TIME GIVEN WHERE THIS
SURFACE BOUNDARY IS EXPECTED TO BE LOCATED TOWARDS 12Z TUESDAY
WILL KEEP A MENTION THE SLIGHT CHANCE FOR LIGHT SNOW GOING ACROSS
MAINLY NORTH CENTRAL KANSAS. WITH THE INCREASING CLOUDS TONIGHT
HAVE DECIDED TO STAY CLOSE TO THE LATEST GUIDANCE WITH
TEMPERATURES FALLING BACK TO AROUND 20 DEGREES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 146 PM CST SUN FEB 15 2015
ANOTHER WEAK SHORTWAVE IS PROGGED TO THE AREA MONDAY NIGHT INTO
TUESDAY INCREASING LIFT ACROSS THE AREA. THIS FEATURE WILL ALSO
PUSH DOWN ANOTHER SHOT OF ARCTIC AIR INTO WESTERN KANSAS. MOSTLY
CLOUDY SKIES ARE ANTICIPATED MONDAY NIGHT WITH A SLIGHT CHANCE OF
LIGHT SNOW ACROSS CENTRAL KANSAS ON TUESDAY. LITTLE TO NO
ACCUMULATION IS EXPECTED WITH THIS SYSTEM. CLOUDS DECREASE IN
COVERAGE TUESDAY NIGHT WITH PARTLY CLOUDY SKIES EXPECTED THROUGH
FRIDAY. THIS IS DUE TO THE UPPER LEVEL RIDGE BUILDING ACROSS THE
WESTERN UNITED STATES. THE NEXT SET OF SHORTWAVES MOVE THROUGH THE
AREA THIS WEEKEND INCREASING CLOUD COVERAGE AS WELL AS INCREASING
THE CHANCE OF PRECIPITATION. HIGHS TUESDAY AND WEDNESDAY LOOK TO
RANGE FROM THE UPPER 30S ACROSS CENTRAL KANSAS TO UPPER 40S ACROSS
FAR SOUTHWESTERN KANSAS WITH LOWS RANGING FROM THE UPPER TEENS
ACROSS CENTRAL KANSAS TO UPPER 20S ACROSS FAR SOUTHWESTERN KANSAS.
HIGHS SLOWLY REACH INTO THE 50S BY FRIDAY AFTERNOON WITH LOWS IN
THE UPPER 20S AND LOWER 30S. COOLER TEMPERATURES ARE EXPECTED THIS
WEEKEND WITH HIGHS IN THE 40S SATURDAY AND UPPER 30S SUNDAY. LOWS
WILL GENERALLY BE IN THE 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN FEB 15 2015
IFR CEILINGS AND LIFR VISIBILITIES CAN BE EXPECTED WITH A BAND OF
STEADY SNOW WHICH WILL BE CROSSING SOUTHWEST KANSAS THROUGH 12Z
MONDAY. THIS IS BASED ON 04Z SURFACE OBSERVATIONS CURRENTLY IN
THE BAND OF STEADIER SNOWFALL ALONG WITH THE AGREEMENT BETWEEN THE
00Z NAM BUFR SOUNDINGS AND LATEST HRRR. THE NAM AND HRRR ALSO
INDICATED THAT THE BETTER CHANCES FOR THESE LOW IFR/LIFR
CONDITIONS WILL OCCUR AT HYS THROUGH 07Z, GCK BETWEEN 06 AND 08Z,
AND THEN DDC BETWEEN 08Z AND 11Z. OUTSIDE THIS AREA OF STEADY
SNOWFALL MVFR CONDITIONS CAN BE EXPECTED THROUGH LATE MORNING.
AFTER 18Z MONDAY THESE LOW CLOUD ARE FORECAST TO GIVE WAY TO VFR
CONDITIONS AS AN UPPER LEVEL TROUGH THAT WILL BE CROSSES WESTERN
KANSAS. WINDS ACROSS WESTERN KANSAS WILL BE NORTH NORTHWEST AT 10
KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 36 21 43 20 / 20 10 10 0
GCK 38 19 42 19 / 10 10 10 0
EHA 38 22 42 22 / 30 10 10 0
LBL 37 21 44 21 / 20 10 10 0
HYS 38 21 38 16 / 10 20 20 0
P28 37 22 42 19 / 40 10 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...HOVORKA_42
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1108 PM CST SUN FEB 15 2015
...UPDATED SYNOPSIS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1105 PM CST SUN FEB 15 2015
AT 00Z MONDAY A 500MB -24C TROUGH WAS LOCATED OVER THE CENTRAL
ROCKIES. 90 TO 110 METER 12HOUR 500MB HEIGHT FALLS WE OBSERVED
JUST EAST OF THIS UPPER TROUGH FROM DENVER TO NORTH PLATTE AND
DODGE CITY. AHEAD OF THIS UPPER TROUGH A 700MB BAROCLINIC ZONE
EXTENDED FROM EXTREME NORTHEAST NEW MEXICO TO NORTHWEST MISSOURI.
THE 850MB COLD FRONT STRETCHED FROM THE PANHANDLE OF TEXAS INTO
SOUTHERN MISSOURI AT 00Z MONDAY. AN AREA OF BETTER 850MB MOISTURE
WAS LOCATED JUST BEHIND THE COLD FRONT AND ANOTHER AREA APPEARING
ACROSS NORTHWEST NEBRASKA BASED ON NORTH PLATTE SOUNDINGS. ACROSS
WESTERN KANSAS EARLIER THIS MORNING THE DODGE CITY SOUNDINGS
INDICATED THAT THE MOIST LAYER WAS LOCATED BETWEEN THE 800MB AND
700MB LEVEL WITH A DECENT DRY LAYER LOCATED NEAR THE SURFACE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 136 PM CST SUN FEB 15 2015
A QUICK HITTING UPPER LEVEL SHORTWAVE TROUGH WILL BE MOVING INTO
WESTERN KANSAS TONIGHT, FROM THE INTERMOUNTAIN WEST, THEN EXIT BY
MORNING. THIS SYSTEM WILL BRING SOME LIGHT ACCUMULATING SNOW TO MOST
OF SOUTHWEST AND SOUTH CENTRAL KANSAS WITH AROUND AN INCH EXPECTED.
ALSO WILL REINFORCE THE COLD AIRMASS INTO KANSAS. NORTHEAST WINDS
WILL BECOME NORTHWEST TOWARDS MORNING AT AROUND 10 MPH WITH
OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S. LIGHT SNOW SHOULD
BEGIN FIRST IN THE I-70 CORRIDOR LATE THIS AFTERNOON AND EARLY
EVENING, THEN DROP SOUTHWARD INTO THE REST OF WESTERN KANSAS BY
AROUND MIDNIGHT TO 3 AM, THEN END BY AROUND 8 TO 10 AM AT MEDICINE
LODGE. MODELS ALL IN FAIRLY GOOD AGREEMENT OF AROUND AN INCH
ACCUMULATIONS WITH SOME 700 MB FRONTOGENESIS AND UPWARD MOTION
WITH THE SHORTWAVE. NEW HPC GUIDANCE ALSO IN LINE WITH CURRENT
FORECAST.
FOR MONDAY, SUBSIDENCE IN BACK OF THE UPPER LEVEL WAVE WILL HELP TO
BREAK OUT A LITTLE SUNSHINE UNDER MOSTLY TO PARTLY CLOUDY SKIES.
LIGHT NORTHWEST WINDS BECOME LIGHT NORTH AROUND 5 TO 10 MPH. HIGHS
WILL BE IN THE MID TO UPPER 30S, WITH THE COOLEST WHERE SOME
RESIDUAL SNOWPACK RESIDES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 146 PM CST SUN FEB 15 2015
ANOTHER WEAK SHORTWAVE IS PROGGED TO THE AREA MONDAY NIGHT INTO
TUESDAY INCREASING LIFT ACROSS THE AREA. THIS FEATURE WILL ALSO
PUSH DOWN ANOTHER SHOT OF ARCTIC AIR INTO WESTERN KANSAS. MOSTLY
CLOUDY SKIES ARE ANTICIPATED MONDAY NIGHT WITH A SLIGHT CHANCE OF
LIGHT SNOW ACROSS CENTRAL KANSAS ON TUESDAY. LITTLE TO NO
ACCUMULATION IS EXPECTED WITH THIS SYSTEM. CLOUDS DECREASE IN
COVERAGE TUESDAY NIGHT WITH PARTLY CLOUDY SKIES EXPECTED THROUGH
FRIDAY. THIS IS DUE TO THE UPPER LEVEL RIDGE BUILDING ACROSS THE
WESTERN UNITED STATES. THE NEXT SET OF SHORTWAVES MOVE THROUGH THE
AREA THIS WEEKEND INCREASING CLOUD COVERAGE AS WELL AS INCREASING
THE CHANCE OF PRECIPITATION. HIGHS TUESDAY AND WEDNESDAY LOOK TO
RANGE FROM THE UPPER 30S ACROSS CENTRAL KANSAS TO UPPER 40S ACROSS
FAR SOUTHWESTERN KANSAS WITH LOWS RANGING FROM THE UPPER TEENS
ACROSS CENTRAL KANSAS TO UPPER 20S ACROSS FAR SOUTHWESTERN KANSAS.
HIGHS SLOWLY REACH INTO THE 50S BY FRIDAY AFTERNOON WITH LOWS IN
THE UPPER 20S AND LOWER 30S. COOLER TEMPERATURES ARE EXPECTED THIS
WEEKEND WITH HIGHS IN THE 40S SATURDAY AND UPPER 30S SUNDAY. LOWS
WILL GENERALLY BE IN THE 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1105 PM CST SUN FEB 15 2015
IFR CEILINGS AND LIFR VISIBILITIES CAN BE EXPECTED WITH A BAND OF
STEADY SNOW WHICH WILL BE CROSSING SOUTHWEST KANSAS THROUGH 12Z
MONDAY. THIS IS BASED ON 04Z SURFACE OBSERVATIONS CURRENTLY IN
THE BAND OF STEADIER SNOWFALL ALONG WITH THE AGREEMENT BETWEEN THE
00Z NAM BUFR SOUNDINGS AND LATEST HRRR. THE NAM AND HRRR ALSO
INDICATED THAT THE BETTER CHANCES FOR THESE LOW IFR/LIFR
CONDITIONS WILL OCCUR AT HYS THROUGH 07Z, GCK BETWEEN 06 AND 08Z,
AND THEN DDC BETWEEN 08Z AND 11Z. OUTSIDE THIS AREA OF STEADY
SNOWFALL MVFR CONDITIONS CAN BE EXPECTED THROUGH LATE MORNING.
AFTER 18Z MONDAY THESE LOW CLOUD ARE FORECAST TO GIVE WAY TO VFR
CONDITIONS AS AN UPPER LEVEL TROUGH THAT WILL BE CROSSES WESTERN
KANSAS. WINDS ACROSS WESTERN KANSAS WILL BE NORTH NORTHWEST AT 10
KNOTS OR LESS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 18 36 23 43 / 90 10 10 10
GCK 19 38 21 42 / 80 10 10 10
EHA 22 38 24 42 / 80 10 10 10
LBL 20 37 24 44 / 80 10 10 10
HYS 15 38 22 38 / 70 10 20 20
P28 17 37 23 42 / 70 30 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...KRUSE
LONG TERM...HOVORKA_42
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1000 PM MST SUN FEB 15 2015
.UPDATE...
ISSUED AT 1000 PM MST SUN FEB 15 2015
PRECIPITATION QUICKLY COMING TO AN END FROM NORTH TO SOUTH THIS
EVENING AS MUCH DRIER AIR MOVES IN. FORECAST AREA SHOULD BE CLEAR
OF PRECIP A FEW HOURS AFTER MIDNIGHT. PER MODEL BOUNDARY LAYER RH
AND VISIBILITY FORECASTS HAVE ADDED PATCHY FREEZING FOG TO THE
WESTERN 1/2 OF THE AREA.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 211 PM MST SUN FEB 15 2015
MAIN FOCUS IN THE SHORT TERM CONTINUES TO BE ON SNOW POTENTIAL THIS
AFTERNOON THROUGH MONDAY AS SHORTWAVE TROUGH CURRENTLY OVER WESTERN
COLORADO/NORTHERN NEW MEXICO SLOWLY EJECTS ACROSS THE PLAINS.
MOST 12Z GUIDANCE (NAM/GFS) AND LATEST SHORT RANGE GUIDANCE
(RAP/HRRR) SEEM TO HAVE BETTER HANDLE ON LOCATION/TIMING OF CURRENT
PRECIP OVER COLORADO/WESTERN NEBRASKA AND HAVE SLOWED DOWN ONSET
OVER OUR CWA. WHILE THERE IS WEAK FORCING PRESENT AND LIGHT RETURNS
ON RADAR OVER OUR NORTHERN CWA...THIS HAS STRUGGLED TO OVERCOME A
1500-2000 KFT SUB CLOUD DRY LAYER WITH AVERAGE TD DEPRESSIONS 15-
20F. AS SHORTWAVE FINAL BEGINS TO EJECT EASTWARD STRONGER FORCING
AND BETTER LOW LEVEL MOISTURE RETURN WILL ALLOW FOR INCREASE IN SNOW
COVERAGE FROM THE WEST TO THE EAST. I COULD STILL SEE SOME SNOW
BEFORE THIS...BUT HIGHER CONFIDENCE IS FOR AFTER 00Z. LOOKS LIKE WE
SHOULD HAVE A BAND FORM OVER EASTERN COLORADO AND MOVE TOWARDS THE
I70 CORRIDOR BEFORE SLIDING SOUTH AROUND MIDNIGHT. GUIDANCE IS STILL
SHOWING SOME WEAK FORCING IN THE WEST AND LIGHT PRECIP SIGNAL. NOT A
LOT OF CONFIDENCE IN THIS AS WE APPEAR TO BE ON SUBSIDENT SIDE OF H3
JET. MODELS ARE STILL SHOWING SOME WEAK MID LEVEL VORTICITY AND A
LIGHT PRECIP SIGNAL IN THE WEST...SO I KEPT SLIGHT CHANCE/CHANCE IN
PLACE FOR NOW. BASED ON CURRENT TIMING AND HIGHEST CONFIDENCE IS
APPEARS WE COULD SEE A QUICK INCH (MAYBE A LITTLE MORE) WITH THE
SNOW THIS EVENING...WITH HRRR/RAP POSSIBLY SUPPORTING RATES OF 0.5"
PER HOUR. THE PROGRESSIVE NATURE OF THE BAND WILL BE THE LIMITING
FACTOR ON AMOUNTS...WHERE IF IT LINGERS COULD RESULT IN ISOLATED 2-
3" TOTALS. OTHERWISE I WOULD ONLY ANTICIPATE A DUSTING OF ADDITIONAL
SNOW AFTER MIDNIGHT THROUGH MONDAY IF THERE IS ANY SNOW LINGERING AT
THAT POINT. NOT ANTICIPATING ADVISORY LEVEL SNOWS AT THIS
POINT...AND THREAT FOR THAT SEEMS TO BE VERY NARROW/ISOLATED IN OUR
SW.
WHILE THERE WILL BE A SLIGHT INCREASE IN WINDS DURING THE DAY MONDAY
(10-15 MPH GUSTING 20 MPH) THIS LIKELY WONT BE ENOUGH TO CAUSE
MAJOR DRIFTING OR VISIBILITY REDUCTIONS ON ITS OWN. HIGH TEMPS WILL
BE TRICKY WITH A SLIGHT MODERATION OF TEMPS ALOFT MONDAY...FIGHTING
LIMITED DIURNAL HEATING DUE TO CLOUD COVER. BEST CHANCE FOR BREAKS
IN SKY COVER WILL BE IN THE NORTHEAST...WHERE IF THEY DO SEE SOME
SUNSHINE COULD REACH THE LOWER 40S. IF STRATUS LINGER...MOST WONT
SEE HIGHS OUT OF THE 30S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 200 PM MST SUN FEB 15 2015
IN THE EXTENDED PERIOD...BOTH THE LATEST GFS AND ECMWF RUNS CONTINUE
TO SHOW H5 RIDGE MEANDERING ALONG OR JUST OFF THE PACIFIC
COAST...WITH BROAD UPPER LOW CIRCULATION OVER MUCH OF THE UNITED
STATES/CANADA. AROUND THIS LOW SEVERAL SHORTWAVES WILL PINWHEEL
SOUTH AND EAST ACROSS THE PLAINS REGION...GIVING THE AREA A CHANCE
FOR LIGHT PRECIPITATION. THE REMNANTS OF THE CURRENT LATE WEEKEND
SYSTEM WILL FINALLY TAPER OFF OVER THE SW PORTION OF THE CWA MONDAY
NIGHT BEFORE SECOND SHORTWAVE DIVES OVER THE REGION ON TUESDAY. DRY
CONDITIONS WILL RETURN TUESDAY NIGHT INTO FRIDAY...BUT A POTENTIAL
PROLONGED SYSTEM COULD AFFECT THE REGION FRIDAY NIGHT ON INTO NEXT
WEEKEND. THIS SYSTEM WILL DIVE OUT OF THE PACIFIC NORTHWEST AS MID
LEVEL FLOW BACKS MORE TOWARDS THE NORTHWEST DURING THIS TIME.
TEMPERATURES IN THE EXTENDED...CAA WILL ARRIVE IN TANDEM WITH THE
SECOND SHORTWAVE DURING THE DAY TUESDAY AND THEN AGAIN OVER THE
UPCOMING WEEKEND WITH THE ARRIVAL OF THE DEEP SHORTWAVE TROUGH.
TUESDAY/S HIGHS WILL ONLY REACH INTO THE 30S BEFORE WARMING SLIGHTLY
IN TO THE 40S TO LOW TO MID 50S BY THURSDAY INTO FRIDAY AHEAD OF
NEXT SYSTEM. THIS WILL BE AIDED BY SURFACE HIGH PRESSURE OFF TO OUR
EAST...AND A LEE-SIDE TROUGH TO OUR WEST THAT WILL SET UP WAA. BY
NEXT WEEKEND... BELOW NORMAL TEMPS WILL SET UPON THE TRI STATE
REGION WITH HIGHS IN THE 30S. OVERNIGHT LOWS WILL RANGE IN THE TEENS
TO L20S.
WINDS IN THE EXTENDED...TUESDAY SEEMS TO BE THE MAIN DAY TO SEE
STRONG WINDS OVER THE AREA AS A JET COINCIDES WITH PASSAGE OF
SHORTWAVE. LATEST BUFKIT SOUNDINGS DO SUGGEST MIXING UP TO 650-700MB
WHERE TUESDAY AFTERNOON HRS COULD HAVE STEADY 30-40MPH WITH GUSTS 50-
55MPH...WHICH WILL COME CLOSE TO HIGH WIND CRITERIA...SO WILL HAVE
TO BE WATCHED. THE OTHER TIMEFRAME FOR POTENTIAL WINDY CONDITIONS
WILL BE OVER NEXT WEEKEND WHERE GUSTS 20-30MPH COULD ACCOMPANY BROAD
SHORTWAVE.
PRECIPITATION IN THE EXTENDED...MAIN P-TYPE WILL BE LIGHT
SNOW/SNOWSHOWERS. HOWEVER...DAYTIME TEMPS ON TUESDAY AND AGAIN WITH
THE SYSTEM OVER NEXT WEEKEND COULD ALLOW FOR SOME LIGHT
RAIN/RAINSHOWERS TO MIX INTO WX SITUATION. GOING FOR OVERALL LIGHT
ACCUM TOTALS IN THE INCH OR SO RANGE WITH LOW QPF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1000 PM MST SUN FEB 15 2015
KGLD...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHWEST WINDS
UNDER 10KTS AT TAF ISSUANCE EXPECTED TO CONTINUE THROUGH 19Z
BEFORE INCREASING TO 12KTS FROM 20Z-23Z. AFTER 23Z WINDS SLOWLY
BACK TO THE WEST-SOUTHWEST NEAR 10KTS. CLOUDINESS PRIMARILY MID
AND UPPER LEVELS. WILL HAVE TO WATCH FOR SOME MVFR CLOUDINESS FROM
TAF ISSUANCE THROUGH 15Z PER NAM AND LESSER EXTENT RUC MOISTURE
CROSS-SECTIONS. MODELS ALSO RATHER PERSISTENT IN PRODUCING SOME
FOG/MIST DURING THE SAME TIME PERIOD. WITH KITR RECENTLY DROPPING
TO IFR CIGS WILL BEGIN THE PERIOD WITH A TEMPO GROUP FOR IFR CIGS.
KMCK...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT/VARIABLE
WINDS AT TAF ISSUANCE EXPECTED TO BECOME NORTHWEST AROUND 6KTS BY
09Z THEN 13KTS FROM 20Z-22Z BEFORE DECREASING TO 10KTS BY 23Z.
WEST-NORTHWEST WINDS AROUND 7KTS EXPECTED AFTER 05Z. CLOUDINESS
CONFINED TO MID AND UPPER LEVELS THROUGH 19Z BEFORE DECREASING BUT
REMAINING VFR FOR THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...99
SHORT TERM...DR
LONG TERM...JN
AVIATION...99
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1230 PM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTH OF
MARITIMES THIS AFTERNOON. HIGH PRESSURE ACROSS THE MIDWEST WILL
BUILD TOWARD THE REGION LATER TONIGHT THROUGH TUESDAY. LOW
PRESSURE WILL PASS SOUTH OF THE AREA TUESDAY. ANOTHER LOW WILL
DEVELOP IN THE GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN IMPACTS WILL CONTINUE TO BE WINDS LEADING TO BLOWING AND
DRIFTING SNOW AND THE DANGEROUS WIND CHILLS THRU MID AFTN.
930 AM UPDATE: WE AGAIN XTNDED THE WNTR WX ADV FOR BLOWING AND
DRIFTING SN TIL 21Z. MANY LCTNS WHO RECEIVED SN FROM THE MOST
RECENT PAST SN EVENT ARE STILL CURRENTLY EXPERIENCING NW WIND
GUSTS IN THE 40 TO 45 MPH RANGE...CREATING DANGEROUS WHITEOUTS ON
ROADWAYS WITH OPEN TERRAIN. WE ALSO XTNDED THE WIND CHILL ADV FOR
THE CNTRL HIGHLANDS AND NW TIL 21Z AS WELL...CANCELLING THE WIND
CHILL ADV FOR ZONE 31 WHERE WIND CHILLS HAVE MODERATED WARMER THAN
20 BELOW.
OTHERWISE...FCST AFTN HI TEMPS AND HRLY TEMPS THRU THE REMAINDER
OF THE AFTN WERE MODIFIED BASED ON RECENT SFC OBS...WHICH
INDICATED TEMPS ALREADY NEAR MANY LCTNS...AND EVEN EXCEEDING AT A
FEW LCTNS. FCST HI TEMPS WERE RAISED ABOUT 2 TO 4 DEG F FROM THE
PREV UPDATE TO REFLECT THIS TREND.
ORGNL DISC: 09Z SURFACE ANALYSIS SHOWED 960MB LOW MOVING ACROSS
THE MARITIMES. VERY STRONG GRADIENT IN PLACE ACROSS THE CWA
W/SUSTAINED WINDS 25 TO 35 MPH AND GUSTS AS HIGH AS 45 MPH. SOME
ELEVATED SITES SUCH AS KFVE(FRENCHVILLE) HAD GUSTS TO 50+ MPH
OVERNIGHT. THE STRONG WINDS WILL CONTINUE INTO THE AFTERNOON AND
THEN GRADUALLY LET UP THIS EVENING INTO THE OVERNIGHT HOURS AS THE
GRADIENT LOOSENS. SOUNDING PROFILES SHOWED GUST POTENTIAL TO 50
MPH AGAIN THIS MORNING INTO EARLY AFTERNOON ESPECIALLY ACROSS
NORTHERN AND EASTERN MAINE(WASHINGTON COUNTY). CENTRAL AND
DOWNEAST AREAS WILL SEE GUSTS HIT 40 MPH AT TIMES W/ANOTHER SURGE
AS SHOWN BY THE SOUNDINGS. THIS WILL LEAD TO BLOWING AND DRIFTING
SNOW W/TRAVEL BEING HAZARDOUS AT TIMES. HANCOCK AND WASHINGTON
COUNTIES WILL EXPERIENCE MUCH OF THIS AND SNOW REMOVAL COULD BE
HAMPERED FOR A TIME. RADAR LOOP SHOWED SOME LIGHT SNOW CONTINUING
WHICH WILL ADD TO THE MIX THIS MORNING. THE SNOW IS FORECAST TO
END BY MID MORNING AS FORCING WEAKENS W/THE LOW LIFTING N. THE
NAM12 AND RAP GUIDANCE WERE DOING A FINE JOB W/THIS SETUP.
VERY COLD TEMPERATURES AND THE CONTINUED WINDY CONDITIONS WILL
LEAD TO DANGEROUS WIND CHILLS TODAY AND AGAIN TONIGHT. WE COULD
ACTUALLY BE SEEING WIND CHILL HEADLINES FOR THE ENTIRE REGION BY
TONIGHT INTO TUESDAY MORNING. STAYED PRETTY CLOSE TO THE DAYCREW`S
ASSESSMENT IN THE TEMPERATURES W/SINGLE NUMBERS ALL THE WAY TO
THE COAST. BELOW ZERO TEMPERATURES OVERNIGHT FOR THE ENTIRE CWA
W/THE NORTHERN AREAS POSSIBLY SEEING 15 TO 20 BELOW ESPECIALLY IN
SHELTERED LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE MID ATLANTIC REGION
EARLY TUESDAY AND THEN TO THE SOUTH OF NOVA SCOTIA TUESDAY NIGHT.
THIS SYSTEM COULD CLIP DOWN EAST MAINE...MAINLY THE COAST WITH A
LITTLE LIGHT SNOW ON TUESDAY BUT AT THIS TIME LITTLE IF ANY
ACCUMULATION IS EXPECTED. OTHERWISE TUESDAY IS SHAPING UP AS
ANOTHER UNSEASONABLY COLD BUT DRY DAY WITH HIGHS GENERALLY IN THE
TEENS MOST AREAS. EXPECT PARTLY TO MOSTLY CLOUDY SKIES TUESDAY
NIGHT. THE NEXT CHANCE FOR SNOW WILL COME LATER WEDNESDAY AS A
NORLUN TROF TYPE FEATURE DEVELOPS IN THE WAKE OF THE DEPARTING
LOW. AT THIS POINT IT APPEARS THE BEST CHANCE FOR SNOW WILL BE
ACROSS THE SOUTHWEST PORTION OF THE FA THROUGH THE DAY WEDNESDAY.
ANY SNOW ACCUMULATIONS THROUGH THE DAY WEDNESDAY SHOULD BE ON THE
LIGHT SIDE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WEDNESDAY NIGHTS AND THURSDAY`S WEATHER WILL BE FOCUSED ON THE
DEVELOPMENT AND PLACEMENT OF A NORLUN TROF TYPE FEATURE AND WEAK
AREA OF LOW PRESSURE THAT IS EXPECTED TO TAKE SHAPE ALONG THE
MAINE MID COAST. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE
PLACEMENT OF THESE FEATURES FOR WEDNESDAY NIGHT AND THURSDAY.
DECIDED TO RAISE POPS TO CATEGORICAL ACROSS THE ENTIRE AREA
WEDNESDAY NIGHT AND INTO THURSDAY AS JUST ABOUT ALL AREAS SHOULD
SEE SOME SNOW. AT THIS TIME IT LOOKS LIKE GENERALLY LIGHT SNOW
ACCUMULATIONS ARE EXPECTED. THIS SYSTEM WILL MOVE AWAY THURSDAY
NIGHT WITH CONTINUED UNSEASONABLY COLD AND MAINLY DRY CONDITIONS
THURSDAY NIGHT AND FRIDAY WITH NOTHING MORE THAN A FEW SNOW
SHOWERS ACROSS NORTHERN AREAS. LOOKING AHEAD...ANOTHER SYSTEM MAY
MAKE A RUN AT THE AREA LATER SATURDAY INTO SUNDAY WITH A CHANCE
FOR MORE SNOW.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
NEAR TERM: IFR ACROSS THE NORTHERN TERMINALS THROUGH MIDDAY AND
THEN MVFR ESPECIALLY W/VSBYS AND BLOWING SNOW. CONDITIONS LOOK TO
IMPROVE TO VFR THIS EVENING INTO THE OVERNIGHT PERIOD. KBGR AND
KBHB SHOULD SEE VFR RIGHT INTO TONIGHT. TURBULENCE WILL BE A
CONCERN TODAY W/GUSTS HITTING 35-40KT ESPECIALLY THE NORTHERN
TERMINALS.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY
NIGHT. VFR EXPECTED MOST OF WEDNESDAY. SNOW WILL DEVELOP WEDNESDAY
NIGHT AND CONTINUE INTO THURSDAY WITH IFR CONDITIONS LIKELY.
CONDITIONS WILL IMPROVE TO VFR THURSDAY NIGHT AND FRIDAY.
&&
.MARINE...
NEAR TERM: AFTER COORDINATING W/GYX, DECIDED TO LOWER THE STORM
WARNING TO A GALE WARNING. GUST POTENTIAL OF 40-45 KT EXPECTED
EARLY TODAY. SUSTAINED WINDS OF 30-35 KT INTO EARLY TONIGHT. IT
DOES LOOK AS THOUGH THE CONDITIONS WILL TRANSITION TO SCA AFTER
MIDNIGHT. HEAVY FREEZING SPRAY EXPECTED RIGHT INTO THE AFTERNOON
AND THE WARNING WAS EXTENDED THROUGH 7 PM. CONDITIONS WILL IMPROVE
LATER IN THE EVENING AS THE WINDS DROP OFF. LOOKS LIKE MODERATE
FREEZING SPRAY BY LATE EVENING INTO THE OVERNIGHT HOURS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS TUESDAY THROUGH WEDNESDAY. SCA CONDITIONS ARE THEN POSSIBLE
AGAIN BY THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MEZ002-005-006-011-017-030-032.
WIND CHILL ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MEZ001-
003-004-010.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
ANZ050>052.
GALE WARNING UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...VJN/DUDA
MARINE...VJN/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1004 AM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTH OF
MARITIMES TODAY. HIGH PRESSURE ACROSS THE MIDWEST WILL BUILD
TOWARD THE REGION LATER TONIGHT THROUGH TUESDAY. LOW PRESSURE WILL
PASS SOUTH OF THE AREA TUESDAY. ANOTHER LOW WILL DEVELOP IN THE
GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN IMPACTS WILL BE WINDS LEADING TO BLOWING AND DRIFTING
SNOW AND THE DANGEROUS WIND CHILLS.
930 AM UPDATE: WE XTNDED THE WNTR WX ADV FOR BLOWING AND DRIFTING
SN TIL 18Z. MANY LCTNS WHO RECEIVED SN FROM THE MOST RECENT PAST
SN EVENT ARE CURRENTLY EXPERIENCING NW WIND GUSTS IN THE 40 TO 45
MPH RANGE...CREATING DANGEROUS WHITEOUTS ON ROADWAYS WITH OPEN
TERRAIN. OTHERWISE...WE XTNDED THE WIND CHILL ADV FOR THE CNTRL
HIGHLANDS AND NW TIL 18Z AS WELL...CANCELLING THE WIND CHILL ADV
FOR ZONES 15...16 AND 17 WHERE WIND CHILLS SHOULD MODERATE TO A
LITTLE WARMER THAN 20 BELOW. OTHERWISE...FCST HRLY CLD CVR AND
TEMPS WERE MODIFIED BASED ON RECENT SAT IMAGERY AND SFC OBS.
ORGNL DISC: 09Z SURFACE ANALYSIS SHOWED 960MB LOW MOVING ACROSS
THE MARITIMES. VERY STRONG GRADIENT IN PLACE ACROSS THE CWA
W/SUSTAINED WINDS 25 TO 35 MPH AND GUSTS AS HIGH AS 45 MPH. SOME
ELEVATED SITES SUCH AS KFVE(FRENCHVILLE) HAD GUSTS TO 50+ MPH
OVERNIGHT. THE STRONG WINDS WILL CONTINUE INTO THE AFTERNOON AND
THEN GRADUALLY LET UP THIS EVENING INTO THE OVERNIGHT HOURS AS THE
GRADIENT LOOSENS. SOUNDING PROFILES SHOWED GUST POTENTIAL TO 50
MPH AGAIN THIS MORNING INTO EARLY AFTERNOON ESPECIALLY ACROSS
NORTHERN AND EASTERN MAINE(WASHINGTON COUNTY). CENTRAL AND
DOWNEAST AREAS WILL SEE GUSTS HIT 40 MPH AT TIMES W/ANOTHER SURGE
AS SHOWN BY THE SOUNDINGS. THIS WILL LEAD TO BLOWING AND DRIFTING
SNOW W/TRAVEL BEING HAZARDOUS AT TIMES. HANCOCK AND WASHINGTON
COUNTIES WILL EXPERIENCE MUCH OF THIS AND SNOW REMOVAL COULD BE
HAMPERED FOR A TIME. RADAR LOOP SHOWED SOME LIGHT SNOW CONTINUING
WHICH WILL ADD TO THE MIX THIS MORNING. THE SNOW IS FORECAST TO
END BY MID MORNING AS FORCING WEAKENS W/THE LOW LIFTING N. THE
NAM12 AND RAP GUIDANCE WERE DOING A FINE JOB W/THIS SETUP.
VERY COLD TEMPERATURES AND THE CONTINUED WINDY CONDITIONS WILL
LEAD TO DANGEROUS WIND CHILLS TODAY AND AGAIN TONIGHT. WE COULD
ACTUALLY BE SEEING WIND CHILL HEADLINES FOR THE ENTIRE REGION BY
TONIGHT INTO TUESDAY MORNING. STAYED PRETTY CLOSE TO THE DAYCREW`S
ASSESSMENT IN THE TEMPERATURES W/SINGLE NUMBERS ALL THE WAY TO
THE COAST. BELOW ZERO TEMPERATURES OVERNIGHT FOR THE ENTIRE CWA
W/THE NORTHERN AREAS POSSIBLY SEEING 15 TO 20 BELOW ESPECIALLY IN
SHELTERED LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE MID ATLANTIC REGION
EARLY TUESDAY AND THEN TO THE SOUTH OF NOVA SCOTIA TUESDAY NIGHT.
THIS SYSTEM COULD CLIP DOWN EAST MAINE...MAINLY THE COAST WITH A
LITTLE LIGHT SNOW ON TUESDAY BUT AT THIS TIME LITTLE IF ANY
ACCUMULATION IS EXPECTED. OTHERWISE TUESDAY IS SHAPING UP AS
ANOTHER UNSEASONABLY COLD BUT DRY DAY WITH HIGHS GENERALLY IN THE
TEENS MOST AREAS. EXPECT PARTLY TO MOSTLY CLOUDY SKIES TUESDAY
NIGHT. THE NEXT CHANCE FOR SNOW WILL COME LATER WEDNESDAY AS A
NORLUN TROF TYPE FEATURE DEVELOPS IN THE WAKE OF THE DEPARTING
LOW. AT THIS POINT IT APPEARS THE BEST CHANCE FOR SNOW WILL BE
ACROSS THE SOUTHWEST PORTION OF THE FA THROUGH THE DAY WEDNESDAY.
ANY SNOW ACCUMULATIONS THROUGH THE DAY WEDNESDAY SHOULD BE ON THE
LIGHT SIDE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WEDNESDAY NIGHTS AND THURSDAY`S WEATHER WILL BE FOCUSED ON THE
DEVELOPMENT AND PLACEMENT OF A NORLUN TROF TYPE FEATURE AND WEAK
AREA OF LOW PRESSURE THAT IS EXPECTED TO TAKE SHAPE ALONG THE
MAINE MID COAST. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE
PLACEMENT OF THESE FEATURES FOR WEDNESDAY NIGHT AND THURSDAY.
DECIDED TO RAISE POPS TO CATEGORICAL ACROSS THE ENTIRE AREA
WEDNESDAY NIGHT AND INTO THURSDAY AS JUST ABOUT ALL AREAS SHOULD
SEE SOME SNOW. AT THIS TIME IT LOOKS LIKE GENERALLY LIGHT SNOW
ACCUMULATIONS ARE EXPECTED. THIS SYSTEM WILL MOVE AWAY THURSDAY
NIGHT WITH CONTINUED UNSEASONABLY COLD AND MAINLY DRY CONDITIONS
THURSDAY NIGHT AND FRIDAY WITH NOTHING MORE THAN A FEW SNOW
SHOWERS ACROSS NORTHERN AREAS. LOOKING AHEAD...ANOTHER SYSTEM MAY
MAKE A RUN AT THE AREA LATER SATURDAY INTO SUNDAY WITH A CHANCE
FOR MORE SNOW.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR ACROSS THE NORTHERN TERMINALS THROUGH MIDDAY AND
THEN MVFR ESPECIALLY W/VSBYS AND BLOWING SNOW. CONDITIONS LOOK TO
IMPROVE TO VFR THIS EVENING INTO THE OVERNIGHT PERIOD. KBGR AND
KBHB SHOULD SEE VFR RIGHT INTO TONIGHT. TURBULENCE WILL BE A
CONCERN TODAY W/GUSTS HITTING 35-40KT ESPECIALLY THE NORTHERN
TERMINALS.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY
NIGHT. VFR EXPECTED MOST OF WEDNESDAY. SNOW WILL DEVELOP WEDNESDAY
NIGHT AND CONTINUE INTO THURSDAY WITH IFR CONDITIONS LIKELY.
CONDITIONS WILL IMPROVE TO VFR THURSDAY NIGHT AND FRIDAY.
&&
.MARINE...
NEAR TERM: AFTER COORDINATING W/GYX, DECIDED TO LOWER THE STORM
WARNING TO A GALE WARNING. GUST POTENTIAL OF 40-45 KT EXPECTED
EARLY TODAY. SUSTAINED WINDS OF 30-35 KT INTO EARLY TONIGHT. IT
DOES LOOK AS THOUGH THE CONDITIONS WILL TRANSITION TO SCA AFTER
MIDNIGHT. HEAVY FREEZING SPRAY EXPECTED RIGHT INTO THE AFTERNOON
AND THE WARNING WAS EXTENDED THROUGH 7 PM. CONDITIONS WILL IMPROVE
LATER IN THE EVENING AS THE WINDS DROP OFF. LOOKS LIKE MODERATE
FREEZING SPRAY BY LATE EVENING INTO THE OVERNIGHT HOURS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS TUESDAY THROUGH WEDNESDAY. SCA CONDITIONS ARE THEN POSSIBLE
AGAIN BY THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MEZ002-005-006-011-017-030-032.
WIND CHILL ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MEZ001-
003-004-010-031.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
ANZ050>052.
GALE WARNING UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...VJN/DUDA
MARINE...VJN/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
612 AM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL CONTINUE TO LIFT NORTH OF
MARITIMES TODAY. HIGH PRESSURE ACROSS THE MIDWEST WILL BUILD
TOWARD THE REGION LATER TONIGHT THROUGH TUESDAY. LOW PRESSURE WILL
PASS SOUTH OF THE AREA TUESDAY. ANOTHER LOW WILL DEVELOP IN THE
GULF OF MAINE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE MAIN IMPACTS WILL BE WINDS LEADING TO BLOWING AND DRIFTING
SNOW AND THE DANGEROUS WIND CHILLS.
610 AM UPDATE: ADJUSTED THE POPS TO LOWER THE PERCENTAGES AND MOVE
THE PLACEMENT FURTHER E AS DEPICTED ON RADAR. SOME MINOR
ADJUSTMENTS WERE MADE TO THE WINDS/GUSTS INITIALLY TO LINE UP
W/THE LAST 3HRS. STILL GETTING GUSTS OF 50+ MPH ACROSS FAR
NORTHERN MAINE ESPECIALLY IN THE ST. JOHN VALLEY. KFVE HAD A PEAK
GUST TO 52 KTS AT 523 AM. WIND CHILL READINGS ARE DROPPING AND
SOME SOME SITES ARE WELL IN THE ADVISORY RANGE W/SOME SITES
HOVERING NEAR WARNING CRITERIA. ATTM, WILL KEEP THE HEADLINES
WHERE THEY ARE AND LET THE DAYCREW RE-ASSESS THE SITUATION.
09Z SURFACE ANALYSIS SHOWED 960MB LOW MOVING ACROSS THE
MARITIMES. VERY STRONG GRADIENT IN PLACE ACROSS THE CWA
W/SUSTAINED WINDS 25 TO 35 MPH AND GUSTS AS HIGH AS 45 MPH. SOME
ELEVATED SITES SUCH AS KFVE(FRENCHVILLE) HAD GUSTS TO 50+ MPH
OVERNIGHT. THE STRONG WINDS WILL CONTINUE INTO THE AFTERNOON AND
THEN GRADUALLY LET UP THIS EVENING INTO THE OVERNIGHT HOURS AS THE
GRADIENT LOOSENS. SOUNDING PROFILES SHOWED GUST POTENTIAL TO 50
MPH AGAIN THIS MORNING INTO EARLY AFTERNOON ESPECIALLY ACROSS
NORTHERN AND EASTERN MAINE(WASHINGTON COUNTY). CENTRAL AND
DOWNEAST AREAS WILL SEE GUSTS HIT 40 MPH AT TIMES W/ANOTHER SURGE
AS SHOWN BY THE SOUNDINGS. THIS WILL LEAD TO BLOWING AND DRIFTING
SNOW W/TRAVEL BEING HAZARDOUS AT TIMES. HANCOCK AND WASHINGTON
COUNTIES WILL EXPERIENCE MUCH OF THIS AND SNOW REMOVAL COULD BE
HAMPERED FOR A TIME. RADAR LOOP SHOWED SOME LIGHT SNOW CONTINUING
WHICH WILL ADD TO THE MIX THIS MORNING. THE SNOW IS FORECAST TO
END BY MID MORNING AS FORCING WEAKENS W/THE LOW LIFTING N. THE
NAM12 AND RAP GUIDANCE WERE DOING A FINE JOB W/THIS SETUP.
VERY COLD TEMPERATURES AND THE CONTINUED WINDY CONDITIONS WILL
LEAD TO DANGEROUS WIND CHILLS TODAY AND AGAIN TONIGHT. WE COULD
ACTUALLY BE SEEING WIND CHILL HEADLINES FOR THE ENTIRE REGION BY
TONIGHT INTO TUESDAY MORNING. STAYED PRETTY CLOSE TO THE DAYCREW`S
ASSESSMENT IN THE TEMPERATURES W/SINGLE NUMBERS ALL THE WAY TO
THE COAST. BELOW ZERO TEMPERATURES OVERNIGHT FOR THE ENTIRE CWA
W/THE NORTHERN AREAS POSSIBLY SEEING 15 TO 20 BELOW ESPECIALLY IN
SHELTERED LOCATIONS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE MID ATLANTIC REGION
EARLY TUESDAY AND THEN TO THE SOUTH OF NOVA SCOTIA TUESDAY NIGHT.
THIS SYSTEM COULD CLIP DOWN EAST MAINE...MAINLY THE COAST WITH A
LITTLE LIGHT SNOW ON TUESDAY BUT AT THIS TIME LITTLE IF ANY
ACCUMULATION IS EXPECTED. OTHERWISE TUESDAY IS SHAPING UP AS
ANOTHER UNSEASONABLY COLD BUT DRY DAY WITH HIGHS GENERALLY IN THE
TEENS MOST AREAS. EXPECT PARTLY TO MOSTLY CLOUDY SKIES TUESDAY
NIGHT. THE NEXT CHANCE FOR SNOW WILL COME LATER WEDNESDAY AS A
NORLUN TROF TYPE FEATURE DEVELOPS IN THE WAKE OF THE DEPARTING
LOW. AT THIS POINT IT APPEARS THE BEST CHANCE FOR SNOW WILL BE
ACROSS THE SOUTHWEST PORTION OF THE FA THROUGH THE DAY WEDNESDAY.
ANY SNOW ACCUMULATIONS THROUGH THE DAY WEDNESDAY SHOULD BE ON THE
LIGHT SIDE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WEDNESDAY NIGHTS AND THURSDAYS WEATHER WILL BE FOCUSED ON THE
DEVELOPMENT AND PLACEMENT OF A NORLUN TROF TYPE FEATURE AND WEAK
AREA OF LOW PRESSURE THAT IS EXPECTED TO TAKE SHAPE ALONG THE
MAINE MID COAST. MODELS ARE IN VERY GOOD AGREEMENT REGARDING THE
PLACEMENT OF THESE FEATURES FOR WEDNESDAY NIGHT AND THURSDAY.
DECIDED TO RAISE POPS TO CATEGORICAL ACROSS THE ENTIRE AREA
WEDNESDAY NIGHT AND INTO THURSDAY AS JUST ABOUT ALL AREAS SHOULD
SEE SOME SNOW. AT THIS TIME IT LOOKS LIKE GENERALLY LIGHT SNOW
ACCUMULATIONS ARE EXPECTED. THIS SYSTEM WILL MOVE AWAY THURSDAY
NIGHT WITH CONTINUED UNSEASONABLY COLD AND MAINLY DRY CONDITIONS
THURSDAY NIGHT AND FRIDAY WITH NOTHING MORE THAN A FEW SNOW
SHOWERS ACROSS NORTHERN AREAS. LOOKING AHEAD...ANOTHER SYSTEM MAY
MAKE A RUN AT THE AREA LATER SATURDAY INTO SUNDAY WITH A CHANCE
FOR MORE SNOW.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR ACROSS THE NORTHERN TERMINALS THROUGH MIDDAY AND
THEN MVFR ESPECIALLY W/VSBYS AND BLOWING SNOW. CONDITIONS LOOK TO
IMPROVE TO VFR THIS EVENING INTO THE OVERNIGHT PERIOD. KBGR AND
KBHB SHOULD SEE VFR RIGHT INTO TONIGHT. TURBULENCE WILL BE A
CONCERN TODAY W/GUSTS HITTING 35-40KT ESPECIALLY THE NORTHERN
TERMINALS.
SHORT TERM: VFR CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY
NIGHT. VFR EXPECTED MOST OF WEDNESDAY. SNOW WILL DEVELOP WEDNESDAY
NIGHT AND CONTINUE INTO THURSDAY WITH IFR CONDITIONS LIKELY.
CONDITIONS WILL IMPROVE TO VFR THURSDAY NIGHT AND FRIDAY.
&&
.MARINE...
NEAR TERM: AFTER COORDINATING W/GYX, DECIDED TO LOWER THE STORM
WARNING TO A GALE WARNING. GUST POTENTIAL OF 40-45 KT EXPECTED
EARLY TODAY. SUSTAINED WINDS OF 30-35 KT INTO EARLY TONIGHT. IT
DOES LOOK AS THOUGH THE CONDITIONS WILL TRANSITION TO SCA AFTER
MIDNIGHT. HEAVY FREEZING SPRAY EXPECTED RIGHT INTO THE AFTERNOON
AND THE WARNING WAS EXTENDED THROUGH 7 PM. CONDITIONS WILL IMPROVE
LATER IN THE EVENING AS THE WINDS DROP OFF. LOOKS LIKE MODERATE
FREEZING SPRAY BY LATE EVENING INTO THE OVERNIGHT HOURS.
SHORT TERM: WIND/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY
LEVELS TUESDAY THROUGH WEDNESDAY. SCA CONDITIONS ARE THEN POSSIBLE
AGAIN BY THURSDAY. LIGHT FREEZING SPRAY IS EXPECTED TUESDAY
THROUGH WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MEZ002-005-006-011-017-030-032.
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MEZ001-
003-004-010-015-016-029-031.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
ANZ050>052.
GALE WARNING UNTIL 1 AM EST TUESDAY FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1229 AM EST MON FEB 16 2015
.SYNOPSIS...
AN INTENSE AREA OF LOW PRESSURE WILL LIFT NORTH OF NOVA SCOTIA
OVERNIGHT. HIGH PRESSURE ACROSS THE MIDWEST WILL BUILD TOWARD THE
REGION THROUGH TUESDAY MORNING. LOW PRESSURE WILL PASS SOUTH OF
THE AREA TUESDAY. ANOTHER LOW WILL DEVELOP IN THE GULF OF MAINE
WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1220 AM UPDATE: HEADLINES WILL REMAIN IN PLACE AS IS FOR THIS
UPDATE. WRAP AROUND SNOW OCCURRING ACROSS NORTHERN AND EASTERN
MAINE AND W/THE STRONG WIND GUSTS, WIDESPREAD BLOWING AND DRIFTING
OCCURRING. THE 03Z RUN OF THE RAP AND NAM12 APPEARED TO HAVE A
GOOD HANDLE ON THE PRECIP SHIELD. 04Z SURFACE ANALYSIS SHOWED
TIGHT PRES GRADIENT AS INTENSE LOW PRESSLOWLY LIFT NORTH ACROSS
THE MARITIMES. IR SATELLITE IMAGERY HAD SOME EHHANCEMENT ROTATING
BACK ACROSS NORTHERN AND EASTERN MAINE AND BOTH THE NAM AND RAP
SHOW THE PRECIP ASSOCIATED W/THE ENHANCEMENT GRADUALLY LIFTING
NORTH THROUGH THE MORNING AND WEAKENING.
THEREFORE, ADJUSTED THE POPS ACROSS THE NORTHERN AND EASTERN AREAS
TO 80% AND EXPECT ANOTHER INCH OR SO OF SNOW BEFORE IT WINDS DOWN.
WINDS WERE SLIGHTLY ADJUSTED BASED ON THE OBS. 50+ MPH GUST AT
KFVE ABOUT AND HOUR AGO.
WINDS WILL CONTINUE TONIGHT AS THE LOW MOVES INTO THE MARITIMES
WITH GUSTS OVER 40 MPH THROUGH THE NIGHT AND DURING MONDAY. WITH
THE ARCTIC AIR IN PLACE...THIS MEANS THAT ALL OF THE FORECAST AREA
WILL EVENTUALLY NEED WIND CHILL ADVISORIES AS SNOW ENDS. HIGHS ON
MONDAY WILL BE MOSTLY IN THE SINGLE DIGITS AND THE WIND CHILL
ADVISORIES MAY BE IN PLACE ALL DAY. THE WINDS WILL ALSO CAUSE
CONTINUED DRIFTING THROUGH TONIGHT AND MONDAY. REDUCED
VISIBILITIES DUE TO BLOWING SNOW SHOULD NOT BE A FACTOR ONCE THE
SNOW ENDS TONIGHT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
THE SHORT TERM WILL CONT TO BE BRISK MON EVE AS THE BACK SIDE PRES
GRAD CONTS TO RETREAT FROM THE REGION WITH DEEP LOW PRES MOVG NE
THRU THE NRN CAN MARITIMES. WE WILL LIKELY NEED WIND CHILL HDLNS
THRU MOST OF THE NGT. ANY LEFT OVR CLDNSS AND FLURRIES SHOULD
EXIT ERN PTNS OF THE FA BY LATE MON NGT...AND THEN WINDS SHOULD
SUBSIDE...SPCLY OVR THE NW BY DAYBREAK TUE...ALLOWING FOR A PD OF
RADIATIONAL COOLING AND A SHALLOW ARCTIC SFC BASE INVSN. WE
THEREFORE LOWER FCST LOWS OVR NW VLYS ABOUT 5 OR SO DEG F OVR MON
NGT.
TUE WILL BEGIN FAIR...THEN THE FIRST OF TWO S/WV IMPULSES BRINGS
INCREASING CLDNSS BY TUE AFTN AND A CHC OF LGT SN TO MSLY DOWNEAST AREAS
BY TUE EVE. AFT A BREAK LATE TUE NGT AND WED MORN...THE
SECOND...STRONGER S/WV WILL BRING A BETTER CHC OF SN TO THE REGION
BEGINNING OVR THE SW PTN OF THE FA WED AFTN. TEMPS WILL MODERATE
SOME FROM TUE AFTN THRU WED...BUT STILL SIG BLO AVG FOR THIS TM OF
SEASON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LOW PRES IN THE GULF OF MAINE WED EVENING WILL LIFT NORTH WED NIGHT
AND THU. IN THE WAKE OF THE LOW HIGH PRES WILL SLOWLY BUILD TOWARD
THE REGION FROM THE WEST AND WILL CREST ACROSS THE AREA AROUND 12Z
SAT. THE NEXT SYSTEM MOVES IN FROM THE WEST SAT NIGHT AND SUN.
ALOFT A DEEP UPPER TROUGH MOVES THROUGH NEW ENGLAND LATE IN THE
WEEK WITH A BROAD TROUGH ALOFT TO REMAIN ENTRENCHED ACROSS THE
EAST FOR THE FORESEEABLE FUTURE.
AS FAR AS THE SENSIBLE WEATHER GOES...SNOW WILL LIKELY BE MOVING
NORTH ACROSS THE AREA WED NIGHT AND MAY CONTINUE INTO THU MORNING
ACROSS THE CROWN OF MAINE. AT THIS TIME IT DOES NOT LOOK TO BE A
MAJOR SNOW PRODUCER...BUT A FEW INCHES OF SNOW ARE POSSIBLE.
DID GO HIGHER THAN THE MODEL CONSENSUS POPS. IN THE WAKE OF THE
LOW IT WILL REMAIN QUITE COLD THROUGH THE END OF THE WEEK WITH
TEMPERATURES AVERAGING ABOUT 15 DEGREES BELOW SEASONAL AVERAGES.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEKEND WITH
SOME MODEST MODERATION OF THE AIR MASS SUNDAY. THE HEMISPHERE
MODELS...CFSV2...CIPS ANALOGS...AND CPC 8-14 DAY ALL INDICATE A
COLDER THAN NORMAL PATTERN PERSISTING THROUGH THE END OF THE
MONTH. THIS WILL END UP AS EITHER THE COLDEST OR ONE OF THE
COLDEST FEBRUARIES ON RECORD FOR MANY AREAS IN NORTHERN AND
EASTERN MAINE.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
NEAR TERM: VFR AT BGR WITH STRONG NW WINDS GUSTING OVER 40 MPH.
ELSEWHERE...IFR CONDITIONS AT BHB WILL END THIS EVENING AND VFR
CONDITIONS WILL COMMENCE. MVFR TEMPO IFR WILL OCCUR AT FVE. IFR
CONDITIONS AT CAR/PQI/HUL WILL END LATER TONIGHT AND GIVE WAY TO
VFR. STRONG NW WINDS GUSTING OVER 40 MPH WILL CONTINUE AT THESE
SITES.
SHORT TERM: GALE CONDITIONS WITH MDT FZG SPY WILL STILL BE IN
PROGRESS MON EVE...WITH WINDS SUBSIDING TO SCA AND FZG SPY TO LGT
INTENSITY BY TUES MORN...WITH A PD OF NO HDLNS XPCTD LATE TUE INTO WED
MORN. SEAS COULD INCREASE TO SCA IN SWELL BY WED EVE. WE WENT
ABOUT 1 TO 2 FT ABV WW3 WV GUIDANCE FOR FCST WV HTS THRU THIS PTN
OF THE FCST.
&&
.MARINE...
NEAR TERM: STORM CONDITIONS AND HEAVY FREEZING SPRAY ARE EXPECTED
THROUGH TONIGHT. HEAVY FREEZING SPRAY CONTINUES MONDAY
MORNING...BUT THE STORM WARNING WILL GIVE WAY TO A GALE WARNING.
SHORT TERM: VFR XPCTD MON NGT INTO TUE MORN...THEN MVFR/IFR CLGS AND
OCNLY VSBYS IN LGT SN XPCTD TUE AFTN THRU WED...MSLY FROM KHUL SWRD
TO KBHB WITH VFR OR MVFR FOR NRN TAF SITES.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MEZ002-005-006-011-016-017-029-030-032.
WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR MEZ001-
003-004-010-015-031.
MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 11 AM EST THIS MORNING FOR
ANZ050>052.
STORM WARNING UNTIL 7 AM EST THIS MORNING FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
658 PM EST TUE FEB 17 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE FEB 17 2015
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER SW HUDSON BAY DOWNSTREAM OF HI AMPLITUDE RDG ALONG THE
W COAST. H5/H7/H85 TEMPS UNDER THE CORE OF THE COLDEST AIR ARND NW
ONTARIO/NE MANITOBA ARE AS LO AS -46C/-33C/-30C RESPECTIVELY.
DESPITE CONSIDERABLE ICE COVER ON LK SUP...ESPECIALLY OVER THE W...
AND THE APRCH OF A WEAK SHRTWV RDG/SOME DNVA...SOME LES CONTINUES IN
THE SN BELTS IMPACTED BY THE COLD NW LLVL FLOW LEFT IN THE WAKE OF A
DISTURBANCE WHICH PASSED LAST NGT. THE MOST OPEN WATER IS LOCATED
OVER THE SCENTRAL PART OF THE LK...SO THE MORE NMRS SN SHOWERS ARE
MOVING INTO THE E HALF OF ALGER COUNTY. LOOKING UPSTREAM...THERE IS
A SHRTWV DIGGING SSEWD THRU MANITOBA. DESPITE PWAT UNDER 0.10
INCH...THERE IS A LARGE AREA OF CLD COVER AND SOME LIGHT SN UNDER
THE DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV WITH 00Z-12Z H5
HGT FALLS AOA 100M AND SOME FAIRLY DEEP MSTR THRU H7 DEPICTED ON THE
12Z YPL ROAB.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON GOING HEADLINES...LES
COVERAGE/AMOUNTS AND TEMPS/LO WIND CHILLS.
TNGT...DIGGING MANITOBA SHRTWV IS PROGGED TO TRACK SSEWD THRU MN AND
INTO WI...WITH DPVA/DEEP LYR QVECTOR CNVGC ON THE CYC SIDE OF THE
TRACK OF THIS FEATURE IMPACTING UPR MI. MODEL FCST SDNGS SHOW DCRSG
STABILITY/DEEPENING MSTR LATE TODAY OVER THE W AND THEN ESPECIALLY
NEAR THE WI BORDER CLOSER TO THE TRACK OF THE DISTURBANCE INTO THE
OVERNGT. WITH THE SHRTWV PASSAGE...THERE WL ALSO BE A REINFORCING
COLD FROPA/WSHFT TO THE NNW THAT IS FCST TO DRAG H85 TEMPS AS LO AS -
30C OVER THE W BY 12Z WED. EARLIER IN THE SEASON...THIS SETUP WOULD
HAVE PRESENTED AN OPPORTUNITY FOR SOME SGNFT LES. BUT CONSIDERABLE
ICE COVER OVER LK SUP AND ABSENCE OF DGZ WITH INFLUX OF BITTERLY
COLD AIR WL GREATLY LIMIT SN TOTALS. THE BEST CHC FOR SOME HEAVIER
LES WL BE IN ALGER COUNTY...WHICH WL BE DOWNWIND OF THE MORE OPEN
WATERS OVER SCENTRAL LK SUP AND IN AREA OF ENHANCED LLVL LAND BREEZE
TYPE CNVGC EXACERBATED BY THE ICE COVER ON LK SUP. BUT WSHFT FM THE
WNW TO NNW IN THE WAKE OF THE COLD FROPA WL SHIFT THE FOCUS FOR THE
MORE NMRS SN SHOWERS FM THE E HALF OF THE COUNTY TO AREAS ARND OR
JUST W OF MUNISING. ALTHOUGH THE DOWNSLOPE NATURE OF THE NW FLOW WL
LIMIT POPS OVER THE SCENTRAL...WL CARRY SOME SCHC/CHC POPS IN THAT
AREA TO ACCOUNT FOR THE PERIOD OF DEEPER HI RH AND DYNAMIC FORCING.
SINCE THE PRES GRADIENT WL TIGHTEN IN THE WAKE OF THE SHRWV
PASSAGE/COLD FROPA...H925 WINDS ARE FCST TO INCRS TO 20-25 KTS
OVERNGT. ALSO...GROWING ICE COVER ON LK SUP WL LIMIT MODERATION OF
THE INCOMING ARCTIC AIRMASS. THESE FACTORS WL RESULT IN AT LEAST
MARGINAL WIND CHILL ADVY CONDITIONS OVER MUCH OF THE W HALF OF UPR
MI AS THE H85 TEMP TUMBLES TOWARD -30C TOWARD 12Z. ALTHOUGH WIND
SPEEDS MAY BE MARGINAL FOR THE ADVY CRITERIA... OPTED TO MAINTAIN
THE GOING HEADLINES AND ADD BARAGA/MARQUETTE COUNTIES TO THE
HEADLINE.
WED...ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE
OF THE SHRTWV PASSAGE WL TEND TO SUPPRESS LINGERING SN SHOWERS
DOWNWIND OF LK SUP AND END THE PCPN COMPLETELY OVER THE SCENTRAL
DURING THE MRNG. AS THE FLOW BACKS A BIT TO THE NW AGAIN...ALGER
COUNTY WL REMAIN THE FOCUS FOR THE MORE NMRS AND HEAVIER SN
SHOWERS...ESPECIALLY IN THE MRNG. MAINTAINED WINTER WX HEADLINE FOR
ALGER COUNTY TNGT THRU WED AND WED NGT /SEE LONG TERM DISCUSSION.
WITH H85 TEMPS REMAINING NOT FAR FM -30C...EXPECT MAX TEMPS TO
STRUGGLE TO REACH ZERO...ESPCIALLY OVER THE NW HALF WHERE THE WIND
CHILL HEADLINE WL RUN UNTIL 18Z.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 PM EST TUE FEB 17 2015
THE OVERALL PATTERN WILL CONTINUE TO BE DOMINATED BY A MID/UPPER
LEVEL RIDGE FROM THE ERN PACIFIC INTO WRN CANADA AND A TROUGH FROM
HUDSON BAY INTO THE CENTRAL AND ERN CONUS. THIS WILL ALLOW ADDITIONAL
BOUTS OF COLD AIR TO MOVE INTO THE WRN LAKES INTO NEXT WEEK WITH
TEMPERATURES REMAINING WELL BELOW NORMAL.
WED NIGHT...THE MAIN FCST ISSUE CONTINUES TO BE THE VERY COLD AIR.
ALTHOUGH WINDS WILL GENERALLY BE LESS THAN 10 MPH...WITH AIR TEMPS
FALLING INTO THE -10 TO -20 RANGE...WIND CHILL VALUES COULD AGAIN
DROP INTO THE -20 TO -30 RANGE EVEN WITH THE WINDS ONLY AROUND 5 MPH.
THE HIGH RES MODELS WERE RELATIVELY CONSISTENT IN FOCUSING LES INTO
ALGER COUNTY DOWNSTREAM OF THE REMAINING OPEN PATCH OF WATER IN THE
DEEPEST PORTION OF LAKE SUPERIOR. FAVORABLE LOW LEVEL CONV IN THE
NARROW OPEN AREA COULD PRODUCE A HEAVIER SNOW BAND WITH ADDITIONAL
SNOW AMOUNTS IN THE 1 TO 4 INCH RANGE ARE EXPECTED.
HOWEVER...CONFIDENCE IS LOW GIVEN THE CHANGING/INCREASING AMOUNTS OF
ICE COVER.
THU AND THU NIGHT...THE ARCTIC HIGH WILL BUILD INTO THE AREA WITH
MAINLY LIGHT WINDS. EXPECT ENOUGH CLEARING FOR TEMPS TO DROP OFF
INTO THE -15 TO 25 RANGE WITH SOME LOCAL READINGS POSSIBLY DOWN TO
AROUND -30F. HOWEVER...MAINLY LIGHT/CALM WINDS SHOULD PREVAIL. ANY
REMAINING LES INTO ALGER COUNTY WILL DIMINISH AND LIFT OFFSHORE AS
WINDS BECOME SW BY EVENING.
FRI INTO FRI NIGHT...A TROUGH MOVING TOWARD THE WRN LAKES WILL
RESULT IN A BROAD WAA PATTERN THROUGH THE REGION. THE MODELS WERE IN
RELATIVELY GOOD AGREEMENT THAT DEEP LAYER ISENTROPIC ASCENT AHEAD
THIS FEATURES WILL PRODUCE SOME LIGHT SNOW. FOR NOW...POPS WERE LEFT
IN THE CHANCE RANGE...BUT WOULD EXPECT THAT IF THE TRENDS HOLD UP A
HIGHER POP LOW QPF/SNOW EVENT WILL DEVELOP WITH OVERALL SNOW AMOUNTS
OF AN INCH OR TWO. THE INCREASING SW FLOW OFF OF LAKE MICHIGAN COULD
BRING A SNOW BAND INTO THE FAR SE CWA BUT WITH THE EXTENSIVE ICE
THAT HAS DEVELOPED OVER NRN LAKE MI...CONFIDENCE IS LOW THAT IT WILL
BRING SIGNIFICANT ADDITIONAL SNOW AMOUNTS.
SAT-TUE...ANOTHER BATCH OF ARCTIC AIR WILL SLIDE INTO THE AREA BY
SUN WITH TEMPS FROM ZERO TO 10 BELOW SAT NIGHT AND IN THE SINGLE
DIGITS SUN. NW WINDS COULD BRING SOME LIGHT SNOW SHOWERS TO THE AREA
FROM ANY REMAINING GAPS IN THE ICE COVER...MAINLY OVER THE EAST
HALF. FCST UNCERTAINTY IS HIGHER BY TUE...AS THE 00Z/12Z ECMWF
REMAINED SIGNIFICANTLY MORE AGGRESSIVE WITH THE NEXT SHRTWV AND
AMOUNT OF COLD MOVING IN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 658 PM EST TUE FEB 17 2015
DESPITE THE CONSIDERABLE ICE COVER OVER WESTERN LAKE
SUPERIOR...THERE CONTINUES TO BE ENOUGH LATENT MOISTURE AND HEAT
FLUXES TO GENERATE SOME LAKE EFFECT SNOW SHOWERS WHICH CONTINUE TO
IMPACT KIWD AND KCMX EARLY IN THE FORECAST. IN ADDITION...WEAK
FORCING ASSOCIATED WITH NEXT IN A SERIES OF SHORT WAVES SLIDING
DOWN THE BACKSIDE OF THE RIDGE WILL HELP INCREASE CLOUD COVER AND
SNOW COVERAGE OVER THE NEXT SEVERAL HOURS. THIS SNOWFALL...WHILE
LIGHT...WILL COMBINE WITH WINDS GRADUALLY VEERING MORE TO THE NW
BEHIND A COLD FRONT...WHICH WILL RESULT IN PERIODS OF IFR/LOW END
MVFR VISIBILITIES AT KCMX AND KIWD OVERNIGHT. SUBSIDENCE MOVING IN
BEHIND THE SHORT WAVE TO BRING A RESPITE TO THE SNOWFALL LATE IN THE
FORECAST. AT KSAW...A BRIEF PERIOD OF VFR TO OCCUR EARLY IN THE
FORECAST WITH THE SNOW AND CLOUD COVER RETURNING BY
MIDNIGHT. CIGS TO THEN STAY MVFR THROUGH THE FORECAST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE FEB 17 2015
WINDS WILL BE MAINLY 30 KTS OR LESS THE REST OF THE WEEK INTO NEXT
WEEKEND. THERE MAY BE A FEW GALE FORCE GUSTS IN THE VCNTY OF STRONG
BAND OF LAKE EFFECT SNOW OVER SCENTRAL LK SUPERIOR LATE TONIGHT
THROUGH WED NIGHT. HEAVY FREEZING SPRAY COULD DEVELOP IN THE LIMITED
OPEN WATER OF SCENTRAL LK SUPERIOR ON WED NIGHT. ICE COVERAGE WILL
CONTINUE TO EXPAND THROUGH THE WEEK AS ARCTIC AIRMASS SETTLES OVER
THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ006.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ TO 1 PM EST /NOON
CST/ WEDNESDAY FOR MIZ001>005-009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...RJT
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
109 AM CST Mon Feb 16 2015
.UPDATE:
Issued at 1253 AM CST Mon Feb 16 2015
Persistent mesoscale band of snow that has deposited 5 to 8 inches
of snow just north of Interstate 70 late this afternoon into this
evening is finally starting to weaken a bit as the main event gets
underway to the south and southwest. Forecast in really good shape
with convective elements feeding northeast from Oklahoma and
southeast Kansas into southern Missouri. Drawing a line from the
northern edge of this new development to our southwest suggests
that locations along and south of the I-44 (MO)/I-70 (IL) will see
moderate and at times heavy snow for most of the overnight hours
into early Monday morning. Could be a "minimum" of snowfall
between the first band and the heavier snowfall to the south,
generally along the Missouri River from Jefferson City to
Washington Missouri. Even in this minimum area believe storm
totals will be nearly 5 inches by the time all is said and done.
For locations to the north where the band was persistent, expect
a strip of 6 to 10 inches (locally more) from near Columbia
Missouri to Brighton Illinois. Along and south of I-44/I-70
Missouri/Illinois should see widespread amounts of 6 to 10 inches,
with locally higher amounts, especially if some of those
convective elements move across the eastern Ozarks.
Expect to have an update out by 2 am.
Issued at 1005 PM CST Sun Feb 15 2015
Band of snow settling across the I-70 corridor currently was a
couple tiers of counties further to the north earlier this evening
where 3 to 5" of snow has fallen already...roughly from a Paris to
Bowling Green MO line and into Hillsboro IL.
One inch per hour and...at times...greater than that...rates can
be found with this band which will now affect the COU/JEF and STL
metro areas for the next several hours.
In the meantime...moisture rich region over the southern Plains
and into southern MO is developing abundant pcpn currently and
this will begin to affect our southern counties into SE MO and far
S IL late tonight and continue thru Monday morning.
While pcpn types have been a bit more complicated than originally
anticipated due to high layer of warm air aloft...about 8kft...
which has given an initial p-type of sleet or snow pellets for
areas near and south of I-70...the models show a suppression of
this layer to the south with time...and should be south of our
region by 12z Monday morning yielding all snow for types. What
will result though...is lower SLRs for southeast MO and far
southern IL until late tonight. But these snow amounts should be
made up once the pcpn becomes all dendritic snow with decent pcpn
amounts expected to persist there beyond 12z.
The Warning was expanded north to where the band initially set up
to the north and enough forecast snow leftover to yield 6" or so
there, with the main thrust of snow accums still expected to come
for areas further south to justify continuing the warnings there.
TES
&&
.SHORT TERM: (Tonight through Monday Night)
Issued at 255 PM CST Sun Feb 15 2015
All data continues to show a winter storm impacting the area tonight
into Sunday, and the 12z model guidance generally is close to the
previous 00z/06z runs adding to the event confidence. That said
there is still significant uncertainty on aspects of the forecast,
namely where the frontogenetical band will set-up and the snow it
will produce before 06z, and the northern edge of snow thereafter.
The overall scenario has changed little since the previous forecast.
Radar currently shows that the initial snow band is trying to
develop from near KSTJ-KMBY-KSET-KSLO in response to strong mid
level frontogenetical forcing and weak warm advection. I have not
seen any snow reports thus far so we are still in the saturation
process due to dry antecedant low levels. Fronotogenetical forcing
and low level warm advection will ramp-up through the remainder of
this afternoon and especially this evening and the expectation is
that this evolving band will intensify producing moderate snowfall
between the 00-06z period. A blend of available short-term
guidance from the RAP, HRRR and deterministic guidance suggests
the band will become established just north of I-70 and become
more west-east oriented producing ~3 inches by 06z.
After 06z conditions begin to change due to the short-wave digging
southeastward into the central Plains. The response appears to be a
southward shift in the mid level frontogenesis and warm advection
supporting this northern band, and increasing large scale ascent
with a vort max head of trof and the backbuilding ULJ. Thus after
06z the primary forcing and ascent shifts southward along and south
of I-70. This would suggest that the northern snow band will fade
while a new and much larger swath of snow spreads/develops across
the southern half of MO/IL. This will place the I-70 corridor on the
northern part of the snow shield and could play havoc with amounts
along the I-70 corridor where the greatest uncertainty in the
forecast resides. Large scale ascent with the migrating short wave
trof and mid level frontogenesis will keep the heart of the snow band
focused south of I-70 across southern MO and southern IL on Sunday
morning with Columbia-St. Louis-Vandalia IL still on the northern
periphery of the deformation snow shield. By mid-late afternoon the
forcing will exit to the east of the area in association with the
migrating short wave trof, bringing and end to the snowfall.
Despite the very cold temperatures and dry nature of the snow, the
sounding profiles continue to show a shallow dendritic growth zone
with much larger profiles supporting columns and plates within the
lift zone. This suggests snow ratios closer to 13-15:1.
The new forecast is not far from the previous one but is a bit lower
in snow totals along I-70 with 5-7 inches due to the uncertainties
discussed, but still looking at 8+ southeast MO into southern IL.
This forecast will need to be further refined this evening in
anticipation of the northern frontogenetic snow band.
No changes needed to the previously issued winter storm watch and
advisories.
Glass
.LONG TERM: (Tuesday through Next Sunday)
Issued at 255 PM CST Sun Feb 15 2015
A cold front wil move southeastward through our forecast area on
Tuesday as a broad positively tilted upper level trough gradually
deepens over the region. There may be some post fronal light snow
Tuesday and Tuesday night, mainly across central and southeast MO
and southwest IL. A secondary cold front will drop southeastward
through our area late Tuesday night and Wednesday morning. Very
cold air is expected to invade our forecast area behind this second
front as a strong surface ridge bulds southeastward into MO from the
northern Plains. The models drop the -24 degree C 850 mb isotherm
southward to near STL on Wednesday. Temperatures on Wednesday and
Wednesday night should be close to 30 degrees below normal due to
this very cold air mass along with snow cover across most of the
forecast area from the recent winter storm. A warming trend should
begin Thursday night due to rising upper level heights along with
surface winds becoming southerly as the surface ridge shifts east of
our area. There may be some light snow Thursday night and Friday,
mainly across southeast MO and southwest IL, due to low-mid level
warm air advection. There will be a better chance of more
significant precipitation Friday night through Sunday as a cold
front sags southward into the area and a southern stream shortwave
approaches. Precipitation type will be in question along and ahead
of the cold front, but should be all snow by Saturday night or
Sunday as another cold air mass drops southward through our area
behind the front.
GKS
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1137 PM CST Sun Feb 15 2015
Band of moderate to occasionally heavy snow just north of I-70
will continue to sink slowly south through the night.
Additionally, sleet and snow will fill in across southeast
Missouri as well. Lighter snow will continue across northern
Missouri and west central Illinois ending toward daybreak. IFR
flight conditions will likely prevail across most of the area
while precipitation continues. Expect improving conditions over
northeast Missouri and west central Illinois as snow tapers off
and finally ends later tonight. Snow will taper off and end from
west to east across central and eastern Missouri into southwest
Illinois from mid morning into early afternoon. Flight conditions
will improve during the morning, but still think that MVFR
ceilings will hang around for most of the day. May see ceilings
scatter out during the evening, but guidance does keep the lower
atmosphere pretty moist so confidence in clearing sky is low.
Specifics for KSTL:
The band of moderate to occasionally heavy snow has been flirting
with the 10nm range ring to the north of Lambert for much of the
evening. However, it should continue to progress slowly south, and
areas of snow will continue to move in from the west and southwest
through the remainder of the night as well. Expect that IFR
conditions will prevail with visibilities near or just above
airport minimums. Think there will be breaks in the heavier snow,
but am not confident in how long/how much improvement there will
be during these breaks. Heavier snow should be tapering off after
12Z and ending completely sometime between 17Z and 20Z. Still
think MVFR ceilings will continue to prevail after the snow ends. May
see ceilings scatter out during the evening, but guidance does
keep the lower atmosphere pretty moist so confidence in clearing
sky is low.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until 6 PM CST this evening FOR Audrain MO-
Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-
Gasconade MO-Iron MO-Jefferson MO-Lincoln MO-Madison MO-
Moniteau MO-Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls
MO-Reynolds MO-St. Charles MO-St. Francois MO-St. Louis
City MO-St. Louis MO-Ste. Genevieve MO-Warren MO-Washington
MO.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Marion
MO-Shelby MO.
IL...WINTER STORM WARNING until 6 PM CST this evening FOR Bond IL-
Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Randolph IL-St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 PM CST this evening FOR Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1157 PM CST Sun Feb 15 2015
.UPDATE:
Issued at 1005 PM CST Sun Feb 15 2015
Band of snow settling across the I-70 corridor currently was a
couple tiers of counties further to the north earlier this evening
where 3 to 5" of snow has fallen already...roughly from a Paris to
Bowling Green MO line and into Hillsboro IL.
One inch per hour and...at times...greater than that...rates can
be found with this band which will now affect the COU/JEF and STL
metro areas for the next several hours.
In the meantime...moisture rich region over the southern Plains
and into southern MO is developing abundant pcpn currently and
this will begin to affect our southern counties into SE MO and far
S IL late tonight and continue thru Monday morning.
While pcpn types have been a bit more complicated than originally
anticipated due to high layer of warm air aloft...about 8kft...
which has given an initial p-type of sleet or snow pellets for
areas near and south of I-70...the models show a suppression of
this layer to the south with time...and should be south of our
region by 12z Monday morning yielding all snow for types. What
will result though...is lower SLRs for southeast MO and far
southern IL until late tonight. But these snow amounts should be
made up once the pcpn becomes all dendritic snow with decent pcpn
amounts expected to persist there beyond 12z.
The Warning was expanded north to where the band initially set up
to the north and enough forecast snow leftover to yield 6" or so
there, with the main thrust of snow accums still expected to come
for areas further south to justify continuing the warnings there.
TES
&&
.SHORT TERM: (Tonight through Monday Night)
Issued at 255 PM CST Sun Feb 15 2015
All data continues to show a winter storm impacting the area tonight
into Sunday, and the 12z model guidance generally is close to the
previous 00z/06z runs adding to the event confidence. That said
there is still significant uncertainty on aspects of the forecast,
namely where the frontogenetical band will set-up and the snow it
will produce before 06z, and the northern edge of snow thereafter.
The overall scenario has changed little since the previous forecast.
Radar currently shows that the initial snow band is trying to
develop from near KSTJ-KMBY-KSET-KSLO in response to strong mid
level frontogenetical forcing and weak warm advection. I have not
seen any snow reports thus far so we are still in the saturation
process due to dry antecedant low levels. Fronotogenetical forcing
and low level warm advection will ramp-up through the remainder of
this afternoon and especially this evening and the expectation is
that this evolving band will intensify producing moderate snowfall
between the 00-06z period. A blend of available short-term
guidance from the RAP, HRRR and deterministic guidance suggests
the band will become established just north of I-70 and become
more west-east oriented producing ~3 inches by 06z.
After 06z conditions begin to change due to the short-wave digging
southeastward into the central Plains. The response appears to be a
southward shift in the mid level frontogenesis and warm advection
supporting this northern band, and increasing large scale ascent
with a vort max head of trof and the backbuilding ULJ. Thus after
06z the primary forcing and ascent shifts southward along and south
of I-70. This would suggest that the northern snow band will fade
while a new and much larger swath of snow spreads/develops across
the southern half of MO/IL. This will place the I-70 corridor on the
northern part of the snow shield and could play havoc with amounts
along the I-70 corridor where the greatest uncertainty in the
forecast resides. Large scale ascent with the migrating short wave
trof and mid level frontogenesis will keep the heart of the snow band
focused south of I-70 across southern MO and southern IL on Sunday
morning with Columbia-St. Louis-Vandalia IL still on the northern
periphery of the deformation snow shield. By mid-late afternoon the
forcing will exit to the east of the area in association with the
migrating short wave trof, bringing and end to the snowfall.
Despite the very cold temperatures and dry nature of the snow, the
sounding profiles continue to show a shallow dendritic growth zone
with much larger profiles supporting columns and plates within the
lift zone. This suggests snow ratios closer to 13-15:1.
The new forecast is not far from the previous one but is a bit lower
in snow totals along I-70 with 5-7 inches due to the uncertainties
discussed, but still looking at 8+ southeast MO into southern IL.
This forecast will need to be further refined this evening in
anticipation of the northern frontogenetic snow band.
No changes needed to the previously issued winter storm watch and
advisories.
Glass
.LONG TERM: (Tuesday through Next Sunday)
Issued at 255 PM CST Sun Feb 15 2015
A cold front wil move southeastward through our forecast area on
Tuesday as a broad positively tilted upper level trough gradually
deepens over the region. There may be some post fronal light snow
Tuesday and Tuesday night, mainly across central and southeast MO
and southwest IL. A secondary cold front will drop southeastward
through our area late Tuesday night and Wednesday morning. Very
cold air is expected to invade our forecast area behind this second
front as a strong surface ridge bulds southeastward into MO from the
northern Plains. The models drop the -24 degree C 850 mb isotherm
southward to near STL on Wednesday. Temperatures on Wednesday and
Wednesday night should be close to 30 degrees below normal due to
this very cold air mass along with snow cover across most of the
forecast area from the recent winter storm. A warming trend should
begin Thursday night due to rising upper level heights along with
surface winds becoming southerly as the surface ridge shifts east of
our area. There may be some light snow Thursday night and Friday,
mainly across southeast MO and southwest IL, due to low-mid level
warm air advection. There will be a better chance of more
significant precipitation Friday night through Sunday as a cold
front sags southward into the area and a southern stream shortwave
approaches. Precipitation type will be in question along and ahead
of the cold front, but should be all snow by Saturday night or
Sunday as another cold air mass drops southward through our area
behind the front.
GKS
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1137 PM CST Sun Feb 15 2015
Band of moderate to occasionally heavy snow just north of I-70
will continue to sink slowly south through the night.
Additionally, sleet and snow will fill in across southeast
Missouri as well. Lighter snow will continue across northern
Missouri and west central Illinois ending toward daybreak. IFR
flight conditions will likely prevail across most of the area
while precipitation continues. Expect improving conditions over
northeast Missouri and west central Illinois as snow tapers off
and finally ends later tonight. Snow will taper off and end from
west to east across central and eastern Missouri into southwest
Illinois from mid morning into early afternoon. Flight conditions
will improve during the morning, but still think that MVFR
ceilings will hang around for most of the day. May see ceilings
scatter out during the evening, but guidance does keep the lower
atmosphere pretty moist so confidence in clearing sky is low.
Specifics for KSTL:
The band of moderate to occasionally heavy snow has been flirting
with the 10nm range ring to the north of Lambert for much of the
evening. However, it should continue to progress slowly south, and
areas of snow will continue to move in from the west and southwest
through the remainder of the night as well. Expect that IFR
conditions will prevail with visibilities near or just above
airport minimums. Think there will be breaks in the heavier snow,
but am not confident in how long/how much improvement there will
be during these breaks. Heavier snow should be tapering off after
12Z and ending completely sometime between 17Z and 20Z. Still
think MVFR ceilings will continue to prevail after the snow ends. May
see ceilings scatter out during the evening, but guidance does
keep the lower atmosphere pretty moist so confidence in clearing
sky is low.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until 6 PM CST Monday FOR Audrain MO-Boone
MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
Iron MO-Jefferson MO-Lincoln MO-Madison MO-Moniteau MO-
Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Reynolds
MO-St. Charles MO-St. Francois MO-St. Louis City MO-St.
Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Marion MO-
Shelby MO.
IL...WINTER STORM WARNING until 6 PM CST Monday FOR Bond IL-Calhoun
IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Randolph IL-
St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1022 PM CST Sun Feb 15 2015
.UPDATE:
Issued at 1005 PM CST Sun Feb 15 2015
Band of snow settling across the I-70 corridor currently was a
couple tiers of counties further to the north earlier this evening
where 3 to 5" of snow has fallen already...roughly from a Paris to
Bowling Green MO line and into Hillsboro IL.
One inch per hour and...at times...greater than that...rates can
be found with this band which will now affect the COU/JEF and STL
metro areas for the next several hours.
In the meantime...moisture rich region over the southern Plains
and into southern MO is developing abundant pcpn currently and
this will begin to affect our southern counties into SE MO and far
S IL late tonight and continue thru Monday morning.
While pcpn types have been a bit more complicated than originally
anticipated due to high layer of warm air aloft...about 8kft...
which has given an initial p-type of sleet or snow pellets for
areas near and south of I-70...the models show a suppression of
this layer to the south with time...and should be south of our
region by 12z Monday morning yielding all snow for types. What
will result though...is lower SLRs for southeast MO and far
southern IL until late tonight. But these snow amounts should be
made up once the pcpn becomes all dendritic snow with decent pcpn
amounts expected to persist there beyond 12z.
The Warning was expanded north to where the band initially set up
to the north and enough forecast snow leftover to yield 6" or so
there, with the main thrust of snow accums still expected to come
for areas further south to justify continuing the warnings there.
TES
&&
.SHORT TERM: (Tonight through Monday Night)
Issued at 255 PM CST Sun Feb 15 2015
All data continues to show a winter storm impacting the area tonight
into Sunday, and the 12z model guidance generally is close to the
previous 00z/06z runs adding to the event confidence. That said
there is still significant uncertainty on aspects of the forecast,
namely where the frontogenetical band will set-up and the snow it
will produce before 06z, and the northern edge of snow thereafter.
The overall scenario has changed little since the previous forecast.
Radar currently shows that the initial snow band is trying to
develop from near KSTJ-KMBY-KSET-KSLO in response to strong mid
level frontogenetical forcing and weak warm advection. I have not
seen any snow reports thus far so we are still in the saturation
process due to dry antecedant low levels. Fronotogenetical forcing
and low level warm advection will ramp-up through the remainder of
this afternoon and especially this evening and the expectation is
that this evolving band will intensify producing moderate snowfall
between the 00-06z period. A blend of available short-term
guidance from the RAP, HRRR and deterministic guidance suggests
the band will become established just north of I-70 and become
more west-east oriented producing ~3 inches by 06z.
After 06z conditions begin to change due to the short-wave digging
southeastward into the central Plains. The response appears to be a
southward shift in the mid level frontogenesis and warm advection
supporting this northern band, and increasing large scale ascent
with a vort max head of trof and the backbuilding ULJ. Thus after
06z the primary forcing and ascent shifts southward along and south
of I-70. This would suggest that the northern snow band will fade
while a new and much larger swath of snow spreads/develops across
the southern half of MO/IL. This will place the I-70 corridor on the
northern part of the snow shield and could play havoc with amounts
along the I-70 corridor where the greatest uncertainty in the
forecast resides. Large scale ascent with the migrating short wave
trof and mid level frontogenesis will keep the heart of the snow band
focused south of I-70 across southern MO and southern IL on Sunday
morning with Columbia-St. Louis-Vandalia IL still on the northern
periphery of the deformation snow shield. By mid-late afternoon the
forcing will exit to the east of the area in association with the
migrating short wave trof, bringing and end to the snowfall.
Despite the very cold temperatures and dry nature of the snow, the
sounding profiles continue to show a shallow dendritic growth zone
with much larger profiles supporting columns and plates within the
lift zone. This suggests snow ratios closer to 13-15:1.
The new forecast is not far from the previous one but is a bit lower
in snow totals along I-70 with 5-7 inches due to the uncertainties
discussed, but still looking at 8+ southeast MO into southern IL.
This forecast will need to be further refined this evening in
anticipation of the northern frontogenetic snow band.
No changes needed to the previously issued winter storm watch and
advisories.
Glass
.LONG TERM: (Tuesday through Next Sunday)
Issued at 255 PM CST Sun Feb 15 2015
A cold front wil move southeastward through our forecast area on
Tuesday as a broad positively tilted upper level trough gradually
deepens over the region. There may be some post fronal light snow
Tuesday and Tuesday night, mainly across central and southeast MO
and southwest IL. A secondary cold front will drop southeastward
through our area late Tuesday night and Wednesday morning. Very
cold air is expected to invade our forecast area behind this second
front as a strong surface ridge bulds southeastward into MO from the
northern Plains. The models drop the -24 degree C 850 mb isotherm
southward to near STL on Wednesday. Temperatures on Wednesday and
Wednesday night should be close to 30 degrees below normal due to
this very cold air mass along with snow cover across most of the
forecast area from the recent winter storm. A warming trend should
begin Thursday night due to rising upper level heights along with
surface winds becoming southerly as the surface ridge shifts east of
our area. There may be some light snow Thursday night and Friday,
mainly across southeast MO and southwest IL, due to low-mid level
warm air advection. There will be a better chance of more
significant precipitation Friday night through Sunday as a cold
front sags southward into the area and a southern stream shortwave
approaches. Precipitation type will be in question along and ahead
of the cold front, but should be all snow by Saturday night or
Sunday as another cold air mass drops southward through our area
behind the front.
GKS
&&
.AVIATION: (For the 00z TAFs through 00z Monday Evening)
Issued at 546 PM CST Sun Feb 15 2015
Band of snow stretching from north of KCOU...north of KSTL...to
around KSLO will continue to increase in coverage this evening
while moving east-southeast. Some showery precipitation south of
the band is being reported as a snow pellets or even some sleet.
IFR conditions with vsbys at or below 1SM are being reported with
the band with mostly VFR vsbys to the north and south of the band.
Another area of snow will develop along and south of the I-70
corridor between 03Z and 09Z tonight which will bring moderate to
heavy snow to these areas as well. Expect IFR conditions to
prevail with visibilities at or below 1SM and ceilings at or below
700 FT. Snow will end from west to east Monday morning into the
early afternoon. As the snow tapers off, expect flight conditions
to improve to MVFR with ceilings most likely hanging between 1000-1900FT.
Specifics for KSTL:
Band of moderate to heavy snow is just north of the STL metro area,
but are seeing increasing radar returns over the past hour in the
vicinity of the terminal. Still think there will be some light
snow or snow grains for the first hour or two and then there the
snow should increase in intensity. Timing on this increasing
intensity is uncertain, but it looks like it should be before 03Z.
Once heavier snow begins, expect IFR vsbys to prevail with
ceilings lowering to IFR as well. Should see snow begin lightening
up overnight with light snow and mvfr conditions continuing into
the late morning or early afternoon. Even after the snow ends, it
looks like ceilings should stay between 1000-1900FT.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER STORM WARNING until 6 PM CST Monday FOR Audrain MO-Boone
MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
Iron MO-Jefferson MO-Lincoln MO-Madison MO-Moniteau MO-
Monroe MO-Montgomery MO-Osage MO-Pike MO-Ralls MO-Reynolds
MO-St. Charles MO-St. Francois MO-St. Louis City MO-St.
Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Marion MO-
Shelby MO.
IL...WINTER STORM WARNING until 6 PM CST Monday FOR Bond IL-Calhoun
IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-Macoupin IL-
Madison IL-Marion IL-Monroe IL-Montgomery IL-Randolph IL-
St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 PM CST Monday FOR Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
855 PM MST TUE FEB 17 2015
.UPDATE...
NW FLOW AGAIN OVER THE REGION BUT NOT NEARLY AS UNSTABLE AS LAST
NIGHT. WE DO HAVE SOME CONVERGENCE/UPSLOPE IN THE BIG HORNS
REGION...BUT DOES NOT SEEM TO BE GENERATING MUCH IF ANY MEASURABLE
PRECIPITATION AT THIS TIME. TWEAKED A FEW ELEMENTS...OTHERWISE
FORECAST IN GOOD SHAPE. BT
&&
.SHORT TERM...VALID FOR WED AND THU...
AN AREA OF LIGHT SNOW SHOWERS STILL HANGING ON FROM ROUNDUP TO
FORT SMITH TO SHERIDAN. AREA RESPONDING TO A WEAK BAROCLINIC ZONE
AND JET DYNAMICS. HRRR LINGERS THIS ACTIVITY THROUGH THE EVENING.
ADDED SOME LOW POPS TONIGHT AS MOISTURE LOOKS RATHER LIMITED. WARM
AIR ALOFT OVERNIGHT WILL CAUSE ACTIVITY TO SHIFT EAST AND BECOME
MORE FLURRIES...SO ADDED LATE TONIGHT INTO WEDNESDAY.
WARMER TEMPERATURES IN STORE FOR WEDNESDAY AS THE RIDGE TO THE
WEST SHIFTS EAST AND FLATTENS OUT. DOWNSLOPE FLOW WILL DRY US OUT
AND ALLOW HIGHS TO REACH THE UPPER 40S TO LOWER 50S OVER WESTERN
AND CENTRAL ZONES. THE EAST WILL BE A LITTLE COOLER AS THE SURFACE
TROUGH DOES NOT QUITE CLEAR THE STATE. WINDS WILL PICK UP OVER THE
WEST WEDNESDAY AFTERNOON AND NIGHT. 700MB WINDS REACH 45KTS AND
LOCAL GUIDANCE TOOLS INDICATE WINDS SHOULD STAY BELOW HIGHLIGHT
CRITERIA...SO LEFT WIND HIGHLIGHTS ON THE SIDELINE. THAT BEING
SAID...SHOULD BE WINDY AND MAINTAINED STRONG WIND GUSTS MENTIONED
IN THE GRIDS.
THE SURFACE TROUGH WILL SLIDE INTO THE DAKOTAS WEDNESDAY NIGHT
AND THURSDAY AND ALLOW ALL LOCATIONS TO EXPERIENCE ABOVE SEASONAL
TEMPERATURES. WEAK ENERGY SLIPS ACROSS THE AREA...BUT WILL BE
STARVED FOR MOISTURE DURING THE DAY. DEEPER MOISTURES FLOWS INTO
THE FORECAST AREA THURSDAY NIGHT BEHIND THE INITIAL WAVE...SO KEPT
POPS IN THEN. TWH
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
AN UPPER LEVEL TROUGH WILL MOVE SOUTH ACROSS IDAHO INTO UTAH
FRIDAY. AS IT DOES...IT WILL DROP ANOTHER COLD FRONT ACROSS OUR
FORECAST AREA USHERING IN GUSTY NORTHERLY WINDS. THIS WILL RESULT
IN AN UNSTABLE NORTH TO NORTHWEST FLOW ALOFT DURING THE DAY AND
CONTINUING THROUGH SATURDAY. SCATTERED RAIN AND SNOW SHOWERS
FRIDAY WILL CHANGE TO ALL SNOW FRIDAY EVENING/NIGHT. THE MOST
FAVORED AREAS FOR ACCUMULATING SNOW WILL BE THE MOUNTAIN
LOCATIONS...AS WELL AS THE BEARTOOTH/ABSAROKA FOOTHILLS. THIS
INITIAL COLD FRONT WILL NOT BE TOO COLD WITH THE COLDER AIR THOUGH
BEING ACROSS OUR FAR EASTERN AREAS. HOWEVER...A SECONDARY SHOT OF
COLD AIR MOVES SOUTH AND FURTHER WEST LATE IN THE DAY SATURDAY
INTO SUNDAY BRINGING ANOTHER CHANCE FOR LIGHT SNOW TO THE FORECAST
AREA. TEMPERATURES FRIDAY WILL BE AT OR SLIGHTLY ABOVE NORMAL
BEFORE DROPPING BELOW NORMAL SATURDAY AND SUNDAY.
HIGH PRESSURE RIDGING BUILDS BACK ACROSS THE FORECAST AREA MONDAY
BRINGING WARMER TEMPERATURES. HOWEVER...THIS LOOKS TO BE SHORT-
LIVED AS ANOTHER DISTURBANCE WILL MOVE SOUTHEAST OUT OF CANADA
ALONG WITH A COLD FRONT LATE TUESDAY/TUESDAY NIGHT BRINGING
ANOTHER CHANCE FOR SNOW ALONG WITH COLDER TEMPERATURES. HOOLEY
&&
.AVIATION...
LIGHT SNOW SHOWERS WILL CONTINUE THROUGH 06Z ACROSS THE CENTRAL
AND SOUTHERN AREAS...MAINLY IMPACTING KSHR WHERE OCCASIONAL MVFR
CONDITIONS WILL BE POSSIBLE. THE MOUNTAINS AND FOOTHILLS AREAS
WILL BE OBSCURED AT TIMES ESPECIALLY ACROSS THE BIG HORN
MOUNTAINS. ELSEWHERE...VFR CONDITIONS WILL PREVAIL THROUGH THIS
EVENING AND OVERNIGHT HOURS. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 020/048 033/056 033/046 027/032 014/032 021/043 027/045
10/B 01/N 23/O 44/S 21/B 12/O 22/O
LVM 024/053 035/054 034/043 025/035 013/033 020/043 029/048
00/N 01/N 24/O 46/S 32/S 12/O 22/R
HDN 017/042 026/053 028/045 025/031 012/031 017/041 024/043
21/E 01/B 23/O 44/S 21/B 12/S 22/O
MLS 007/030 019/045 025/040 020/025 007/027 017/038 019/038
11/M 11/B 23/O 32/S 21/B 12/S 22/S
4BQ 009/031 021/048 026/043 022/029 009/028 016/041 021/040
11/M 01/B 23/O 33/S 21/B 02/S 22/O
BHK 903/024 013/039 024/037 015/020 002/023 013/035 016/034
01/B 12/W 23/O 32/S 10/U 02/S 22/S
SHR 015/041 024/052 026/041 022/029 009/027 011/040 022/042
20/B 01/B 24/O 45/S 32/S 12/S 22/O
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
300 PM CST MON FEB 16 2015
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 300 PM CST MON FEB 16 2015
THE PRIMARY FORECAST CONCERN IS POTENTIAL FOR A BAND OF ACCUMULATING
SNOW ACROSS PARTS OF EASTERN NEBRASKA TONIGHT.
UPPER AIR CHARTS FROM 12Z HAD THE FOLLOWING MAIN FEATURES. A STRONG
JETSTREAM WAS NOTED AT 300 MB FROM ALBERTA INTO UTAH...WITH A
COUPLE OF JET SEGMENTS OF OVER 130 KNOTS. A STRONGER JET SEGMENT
OF AROUND 170 KNOTS WAS OVER PENNSYLVANIA. A BROAD AREA OF 12 HOUR
HEIGHT FALLS OF 50 METERS OR MORE AT 500 MB EXTENDED FROM UTAH TO
IOWA AND FROM SOUTH DAKOTA TO TEXAS. A STRONG RIDGE WAS LOCATED
FROM OFF THE CALIFORNIA COAST UP INTO THE YUKON. WINDS WERE
GENERALLY FROM THE NORTHWEST IN THE LOWER AND MIDDLE TROPOSPHERE
FROM OUR AREA NORTHWEST INTO CANADA. PREVIOUSLY MENTIONED 500 MB
RIDGE TO OUR WEST WILL BUILD EAST AND THEN FLATTEN THROUGH
THURSDAY...WHILE A CLOSED LOW FORMS AND DROPS SOUTHEAST ACROSS
ONTARIO AND INTO THE EASTERN GREAT LAKES REGION.
A FAST MOVING SHORTWAVE IN COMBINATION WITH A COMPACT LOW PRESSURE
CENTER SHOULD BRING A BAND OF LIGHT SNOW TO THE REGION TONIGHT.
THE EXACT PLACEMENT OF THIS BAND IS SOMEWHAT UNCERTAIN...BUT THE
LATEST MODEL CONSENSUS (USING A BLEND OF 12Z NAM...18Z NAM...19Z
13 KM RAP ...18Z HRRR AND 15Z SREF MEAN) PLACES THE AXIS FROM
PARTS OF NORTH CENTRAL NEBRASKA INTO NORTHEAST KANSAS. BEST
POTENTIAL IS LIKELY JUST NORTH AND NORTHEAST OF THE TRACK OF THE
SURFACE LOW PRESSURE CENTER. SOUNDINGS...MID LEVEL FRONTOGENESIS
AND IMPRESSIVE 700 MB OMEGA VALUES IN THE DENDRITIC GROWTH ZONE
FROM THE NAM SUGGEST THE ATMOSPHERE MAY PRODUCE SOME AMOUNTS OVER
ONE INCH IN PARTS OF CENTRAL OR SOUTHEAST NEBRASKA DOWN INTO
NORTHEAST KANSAS. BUT WE HAVE MAX AMOUNTS AROUND ONE INCH FOR NOW
AND WILL MENTION THE LOCALIZED POTENTIAL FOR HIGHER AMOUNTS IN THE
HWO. THAT SYSTEM SHOULD PUSH QUICKLY SOUTH OUT OF OUR AREA BY
ABOUT SUNRISE...BUT SOME ISOLATED TO SCATTERED SNOW SHOWERS MAY
OCCUR INTO THE AFTERNOON HOURS. AFTER THAT...SNOW CHANCES SEEM LOW
FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUT A SLIGHT CHANCE
OF SNOW WILL RETURN BY THURSDAY.
COLD CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH FROM ALBERTA
AND SASKATCHEWAN THROUGH WEDNESDAY. WIND CHILLS MAY REACH NEAR
ADVISORY VALUES IN THE NORTH AND NORTHEAST PARTS OF THE FORECAST
AREA LATE TUESDAY NIGHT AND WEDNESDAY MORNING...BUT WILL NOT ISSUE
AN ADVISORY AT THIS POINT. THEN AS THE RIDGE MOVES OFF TO THE
SOUTHEAST AND SOUTHERLY RETURN FLOW DEVELOPS...TEMPERATURES WILL
MODERATE A BIT.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 300 PM CST MON FEB 16 2015
500 MB RIDGE WILL DEVELOP AGAIN FROM THE EASTERN PACIFIC UP INTO
THE YUKON FROM THURSDAY NIGHT INTO SUNDAY. LATEST RUNS OF THE
GFS... ECMWF AND CANADIAN MODELS AGREE ON THE GENERAL LARGE SCALE
FEATURES INTO SUNDAY. DETAILS START TO DIVERGE EARLY NEXT
WEEK...AND CONFIDENCE FALLS TO BELOW NORMAL BY THAT TIME. HAD TO
INCLUDE SOME LOW POPS FOR LIGHT SNOW CHANCES MUCH OF THIS PERIOD.
FRIDAY LOOKS LIKE THE WARMEST DAY...WHEN WE SHOULD SEE HIGHS IN
THE 40S WEST AND 30S EAST. LOWS WILL BE MOSTLY IN THE TEENS...BUT
UPPER TEENS TO MID 20S FOR FRIDAY NIGHT.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1150 AM CST MON FEB 16 2015
AREA WILL REMAIN UNDER THE INFLUENCE OF BROAD NORTHWEST FLOW WITH
TIMING OF SHORT WAVE ENERGY THE MAIN CHALLENGE. WIDESPREAD VFR
CIGS AOB FL050 EXPECTED TO PREVAIL THROUGH THE PERIOD. KLNK COULD
SEE SOME MVFR CIGS AND VSBY AFTER 09Z AS WEAK UPPER WAVE TRIGGERS
SOME LIGHT SNOW POTENTIAL.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...FOBERT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1030 PM EST TUE FEB 17 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL MOVE EAST ACROSS THE REGION WEDNESDAY
AFTERNOON AND EARLY EVENING. DANGEROUSLY COLD AIR WILL SURGE INTO
THE REGION WEDNESDAY NIGHT... LASTING INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1010 PM TUESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE TONIGHT THROUGH 1000 AM
WEDNESDAY...
TONIGHT:
A WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT
THROUGH 10 AM WEDNESDAY MORNING AS MANY ROADS (ESPECIALLY UNTREATED
SECONDARY ROADS) HAVE OR WILL REFREEZE TONIGHT WITH WHATS LEFT OF
ICE/SNOW/SLEET MELT ON THEM OR REMAIN SLEET/SNOW/ICE COVERED.
THE MAIN MID AND HIGH CLOUD SHIELD IS GENERALLY PUSHING OFF TO THE
NORTH AND EAST OF THE AREA THIS EVENING. HOWEVER... WITH THE MAIN
DEEP TROUGH AXIS TO THE WEST OF THE REGION AND ANOTHER EMBEDDED S/W
LOCATED OVER OK/TX SHIFTING EAST/NORTHEASTWARD EXPECT WE WILL STILL
SEE SOME MID AND HIGH CLOUDS MOVE ACROSS THE REGION OVERNIGHT. BOTH
THE HRRR AND NAM HAVE PICKED UP ON THE FACT THAT DEWPOINTS HAVE
REMAINED HIGHER THAN EXPECTED ACROSS THE AREA THIS EVENING. BOTH THE
NAM AND HRRR SHOW SOME SORT OF WEAK BOUNDARY DROPPING SOUTHWARD OUT
OF VA LATE THIS EVENING INTO THE OVERNIGHT (SHOWN MAINLY IN
DEWPOINT FIELDS). HOWEVER... BOTH THE NAM AND HRRR SHOW THIS WEAK
BOUNDARY STALLING AS IT TRIES TO PUSH INTO SOUTHERN PORTIONS OF THE
AREA... WITH POCKETS OF DENSE FOG AND LOW CLOUDS DEVELOPING ACROSS
THE SOUTHERN PIEDMONT AND SANDHILLS. IN FACT SOME IFR TO AT TIMES
LIFR FOG HAS DEVELOPED ACROSS THE SOUTHERN PIEDMONT ALREADY.
THUS... WE PLAN ON RAISING LOW TEMPS ACROSS SOUTHERN PORTIONS OF THE
AREA THIS EVENING AND PARTS OF THE COASTAL PLAIN. GIVEN WE ALREADY
HAVE A WINTER WEATHER ADVISORY FOR BLACK ICE OUT FOR THE ENTIRE
AREA... DO NOT PLAN ON ISSUING ANY ADDITIONAL HEADLINES FOR
THE POSSIBILITY OF SOME POCKETS OF FREEZING FOG. EXPECT LOW TEMPS TO
RANGE FROM THE UPPER TEENS NORTH TO THE MID TO UPPER 20S SOUTH.
WEDNESDAY:
IT APPEARS THAT A VERY BRIEF WINDOW OF TIME FOR SOME MODERATION IN
TEMPERATURES WILL OCCUR WEDNESDAY BEFORE THE BOTTOM LITERALLY
FALLS OUT. HOWEVER... STRONG HEIGHT FALLS OUT AHEAD OF THE
APPROACHING LEAD VORTICY MAXIMUM WILL QUICKLY LEAD TO INCREASING
CLOUDINESS AND WILL SHUT DOWN THE WARMING IN THE PIEDMONT. JUST AS
WITH THE ARCTIC FRONT THAT PASSED THROUGH THE REGION LAST
WEEKEND... THERE IS A CHANCE OF SHOWERS WITH THIS FRONT. THE BEST
CHANCE OF SHOWERS APPEARS TO THE FOR THE NORTHERN AREAS OF THE
PIEDMONT... FROM THE TRIAD TO THE TRIANGLE AREAS... BETWEEN NOON
AND 500 PM. A SHORT PERIOD OF LIFT ALONG WITH STEEPENING LAPSE
RATES BETWEEN THE SURFACE AND H7 AND MOISTENING FROM THE SURFACE
THROUGH THE -15/-20C LEVEL JUSTIFIES GOOD CHANCES OF SHOWERS IN
THESE AREAS. SATURATION AND LIFT WILL BE LESS TO THE SOUTH AND
EAST WHERE ONLY SLIGHT CHANCES WILL BE FORECAST. THE TEMPERATURE
PROFILES SUGGEST SNOW SHOWERS AS THE MAIN PRECIPITATION TYPE.
HOWEVER... THE BOUNDARY LAYER SHOULD REVEAL TEMPERATURES
APPROACHING 40 BRIEFLY BEFORE THE FRONTAL PASSAGE. THEREFORE...
SNOW ACCUMULATIONS ARE NOT ANTICIPATED OTHER THAN POSSIBLY A LIGHT
DUSTING (UNDER A HALF INCH) IN HEAVIER BUT BRIEF SHOWERS... AND
CONFINED TO THE NORTHERN PIEDMONT AS MENTIONED BEFORE. HIGHS MID
30S NW TO MID 40S SE... FALLING LATE AFTERNOON IN THE NW.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
AS OF 337 PM TUESDAY...
...PREPARE FOR DANGEROUS LIFE THREATENING COLD...
NW WINDS 15-25 MPH WILL GUST TO 35-40 MPH WEDNESDAY NIGHT WITH
RAPIDLY CLEARING EXPECTED. VERY INTENSE COLD AIR ADVECTION WILL
LEAD TO LOWS OF 5-15 NW TO SE BY THURSDAY MORNING.
WIND CHILL ADVISORIES WILL LIKELY BE NEEDED WEDNESDAY NIGHT AND
THURSDAY WHEN WIND CHILL INDICES SHOULD RANGE BETWEEN ZERO AND 15
BELOW ZERO.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...
...POTENTIALLY HISTORIC ARCTIC AIR MASS WILL CONTINUE TO BE IN
PLACE WITH RECORD LOW/LOW MAXIMUM TEMPERATURES EXPECTED
THURSDAY...THURSDAY NIGHT...FRIDAY AND POSSIBLY FRIDAY NIGHT...
THIS COLD WAVE SHOULD RIVAL THE COLD WAVES THAT HAVE OCCURRED IN
FEBRUARY... POTENTLY SETTING MONTHLY COLD RECORDS AS WELL.
THURSDAY THROUGH FRIDAY NIGHT: THIS PART OF THE FORECAST IS EXPECTED
TO BE DRY WITH RECORD SETTING TEMPERATURES. THE UPPER LEVEL HIGH
WILL REMAIN OVER SOUTHERN ONTARIO AND NEW ENGLAND...WITH THE TROUGH
EXTENDING SOUTH THROUGH THE MID-ATLANTIC...SLOWLY PROGRESSING
EASTWARD OFF THE COAST. MEANWHILE AT THE SURFACE...THE COASTAL LOW
WILL CONTINUE ITS NORTHEAST TREK AS THE ARCTIC HIGH BUILDS INTO THE
REGION. SUBSIDENCE UNDER THE NW FLOW AS THE HIGH BUILDS IN WILL KEEP
CENTRAL NC DRY...BUT BITTER COLD. THE TIGHT PRESSURE GRADIENT
BETWEEN THE EXITING LOW AND APPROACHING HIGH WILL RESULT IN FAIRLY
DESCENT WINDS IN THE 10-20 MPH RANGE ON THURSDAY. THE WINDS WILL
ABATE THURSDAY NIGHT AS THE HIGH MOVES OVER THE AREA...WITH
GENERALLY LIGHT AND VARIABLE WINDS THROUGH FRIDAY NIGHT.
TEMPERATURES: WITH HIGHS ON THURSDAY ALREADY AS LOW AS THE MID TEENS
IN THE NORTH TO MID 20S SOUTH...THE WIND MAY STILL PRODUCE WIND
CHILLS BELOW ZERO FOR MUCH OF THE DAY THURSDAY. THURSDAY NIGHT
LOWS SHOULD DIP TO BETWEEN 0 AND 5 NW TO NEAR 10 SE. SOME SUB-ZERO
READINGS WILL BE POSSIBLE IN THE PIEDMONT WHERE THE ICE/SNOW PACK
REMAINS. FAIRLY HIGH CONFIDENCE THAT HIGHS ON FRIDAY WILL REMAIN
BELOW FREEZING...MID 20S NORTH TO UPPER 20S SOUTH. LOWS SHOULD
REBOUND SLIGHTLY ON FRIDAY NIGHT...MAINLY IN THE 10-15 DEGREE
RANGE BUT STILL CLOSE TO RECORD VALUES (SEE CLIMATE SECTION
BELOW).
SATURDAY AND SUNDAY: THERE IS SLIGHTLY BETTER AGREEMENT BETWEEN THE
MODELS FOR THE WEEKEND...HOWEVER CONFIDENCE IS STILL LOW ON HOW MUCH
AND WHAT TYPE OF PRECIPITATION WE WILL SEE AND WHEN IT WILL OCCUR.
THERE IS A CHANCE THAT A COLD AIR WEDGE WILL SET UP OVER THE NC
PIEDMONT ON SATURDAY...AND WITH AN APPROACHING LOW PRESSURE SYSTEM
FROM THE WEST...EXPECT BEST CHANCES FOR PRECIP TO BE ACROSS THE NW
ON SATURDAY...WITH THE SANDHILLS LIKELY REMAINING DRY. FREEZING
RAIN AND/OR SLEET MAY OCCUR IF THE PRECIPIATION CAN SNEAK INTO
THE NW PIEDMONT BEFORE THE ARCTIC AIR RETREATS. THIS IS BECOMING
AN INCREASING POSSIBILITY. WE WILL HAVE TO KEEP WATCHING THIS ONE
FOR ICING POTENTIAL.
AS OF THE LATEST MODEL RUNS...SUNDAY AND SUNDAY NIGHT LOOK TO BE
THE WETTEST AS THE COLD FRONT APPROACHES AND MOVES THROUGH NC.
RAIN IS PREFERRED... BUT MODELS MAY BE BLOWING AWAY THE EXTENSIVE
COLD AIR TOO SOON. TEMPS WILL BE DIFFICULT TO FORECAST GIVEN THE
UNCERTAINTY OF THE WEDGES EXISTENCE AND HOW LONG/WHERE IT WILL
LINGER. BOTH MODELS AGREE THAT THE COLD FRONT WILL BE MOST OF THE
WAY THROUGH CENTRAL NC BY 12Z MONDAY. FOR NOW...EXPECT HIGHS IN
THE 30S NORTHWEST TO MID 40S SOUTHEAST ON SATURDAY...INCREASING
INTO THE 40S AND 50S ON SUNDAY.
MONDAY AND TUESDAY: THE PRECIPITATION SHOULD MOVE OUT OF THE AREA
WITH THE FRONT ON MONDAY...WITH HIGH PRESSURE BUILDING INTO THE
REGION BEHIND IT. COOLER TEMPERATURES WILL RETURN EARLY NEXT WEEK
WITH HIGHS MAINLY IN THE LOW TO MID 40S AND LOWS IN THE MID 30S TO
AROUND 30 DEGREES.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 PM TUESDAY...
24-HOUR TAF PERIOD: SOME GUIDANCE SUGGEST MVFR CEILINGS AND/OR
VISIBILITIES COULD DEVELOP ACROSS THE AREA BETWEEN 06 TO 12Z OWING
TO COOLING EFFECT AND LOW-LEVEL MOISTURE ASSOCIATED WITH THE
LEFTOVER ICE/SNOW ON GROUND. HOWEVER...CONFIDENCE IS TOO LOW TO
INCLUDE AT THIS TIME.
CEILINGS WILL LOWER TO LOW END VFR TO MVFR IN ADVANCE OF AN ARCTIC
COLD FRONTAL PASSAGE AND VIGOROUS UPPER LEVEL DISTURBANCE THROUGH
THE AREA BETWEEN 18Z WED TO 00Z THU. A BROKEN BAND OF SHALLOW
CONVECTION IS EXPECTED TO ACCOMPANY THE FRONT. THE ATMOSPHERE
REMAINS SUFFICIENTLY COLD ALOFT THAT ANY PRECIP WILL FALL AS SNOW
SHOWERS ACROSS MOST OF THE AREA. A BRIEF 1 TO 2 HOUR OF IFR CEILINGS
AND RESTRICTIONS WILL BE POSSIBLE WITH THE STRONGER CONVECTION.
LOOKING AHEAD: EXPECT VFR CONDITIONS TO RETURN WEDNESDAY NIGHT WITH
BREEZY WEST-NORTHWESTERLY WINDS OF 20 TO 25KTS ON THURSDAY. ANOTHER
UPPER LEVEL DISTURBANCE MOVING THROUGH THE AREA COULD BRING A PERIOD
OF MVFR CEILINGS ON THURSDAY. THE NEXT STORM SYSTEM WILL APPROACH
THE AREA ON LATE FRIDAY NIGHT AND INTO SATURDAY...BRINGING
WIDESPREAD SUB-VFR CONDITIONS TO THE AREA...ALONG WITH THE POTENTIAL
FOR SOME WINTRY PRECIPITATION ACROSS THE NORTHWEST AND CENTRAL
PIEDMONT ON SATURDAY...WITH EVENTUAL CHANGEOVER TO RAIN BY SUNDAY.
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...RAH
SHORT TERM...BADGETT
LONG TERM...KC
AVIATION...CBL
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1002 PM EST TUE FEB 17 2015
.SYNOPSIS...
ANOTHER ARCTIC FRONT WILL CROSS THE AREA FROM WEST TO EAST THIS
EVENING INTO WEDNESDAY. ARCTIC HIGH PRESSURE WILL BE OVERHEAD BY
FRIDAY MORNING. THE NEXT COLD FRONT WILL DROP ACROSS THE GREAT
LAKES ON SATURDAY. A WAVE OF LOW PRESSURE MAY DEVELOP ON THE
FRONT.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
ENHANCED AREA OF SNOWFALL CONTINUES TO MOVE TO THE EAST NORTHEAST
ONTO LAKE ERIE THIS EVENING. RUC MODEL INDICATES THIS TREND WILL
CONTINUE. HOWEVER WE WILL NEED TO MONITOR NE OHIO INTO NW PA FOR A
BAND OF SLIGHTLY HEAVIER SNOWFALL. FORTUNATELY THIS AREA OF OF
STEADY LIGHT SNOW SHOULD KEEP MOVING AND LIMIT AMOUNTS. STILL
LOOKS LIKE AROUND AN INCH WILL BE THE HIGH SIDE FOR ACCUMULATIONS.
THESE HEAVIER AMOUNTS WILL LIKELY BE CLOSER TO THE
LAKESHORE...ESPECIALLY NEAR TOLEDO AND ACROSS EXTREME NE OHIO INTO
NW PA.
TEMPERATURES CONTINUE TO WARM SLIGHTLY AHEAD OF THE ARCTIC
BOUNDARY THIS EVENING. THE BOUNDARY WAS LOCATED FROM NEAR THE
THUMB OF MICHIGAN SOUTHWEST TO NEAR THE INDIANA/OHIO BORDER AS OF
03Z. THIS BOUNDARY WILL CONTINUE EASTWARD THROUGH THE OVERNIGHT
WITH TEMPERATURES DROPPING BACK INTO THE SINGLE DIGITS. THIS WILL
ALLOW WIND CHILL TEMPERATURES TO DIP TO AROUND 10 DEGREES BELOW
ZERO AROUND SUNRISE. SO IT WILL BE A CLOSE CALL FOR THE NEED OF A
WIND CHILL ADVISORY.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
THE FLOW WILL BE SOUTHWEST WEDNESDAY MORNING WITH PLENTY OF
MOISTURE AROUND...SO WILL KEEP CHANCE POPS. GOING WITH LIKELY FOR
THE SNOW BELT IN THE AFTERNOON AS THE FLOW BECOMES WNW WEDNESDAY
AFTERNOON. CONTINUING CHANCE POPS EVERYWHERE ELSE AS THE UPPER TROF
MOVES THROUGH.
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE SNOW BELT HAS THE
BEST CHANCE FOR SNOW WITH LOW POP CHANCES EVERYWHERE ELSE DECREASING
WITH TIME AS THE AIRMASS DRIES OUT AND THE HIGH STARTS BUILDING IN
FROM THE WEST. ON THE EDGE ABOUT THE AMOUNTS IN THE SNOW BELT. THE
NW FLOW IS USUALLY NOT THAT GOOD FOR SIGNIFICANT SNOWFALL AMOUNTS
EXCEPT OVER INLAND NW PA. HOWEVER...WITH THE AIRMASS SO DRY AND LAKE
ERIE FROZEN WE WILL NEED HELP FROM OTHER LAKES...EVEN FOR NW PA. WILL
CONTINUE TO MONITOR THIS THREAT.
DRY FRIDAY AND THEN A CHANCE OF SNOW FRIDAY NIGHT AS THE NEXT SYSTEM
APPROACHES. AT THIS TIME THE TIMING IS IN QUESTION BUT WILL NOT PUT
ANY RESOLUTION IN UNTIL THE TRENDS BECOME CLEARER.
THE MAIN THREAT WITH THIS NEXT SURGE OF COLD AIR WILL BE WIND
CHILLS. AT THIS TIME IT SEEMS LIKE A WIND CHILL ADVISORY WILL BE
GOOD ENOUGH. THE THREAT FOR NEEDING THIS HEADLINE WILL START
WEDNESDAY EVE AND LAST INTO FRIDAY MORNING. DID NOT ISSUE A
HEADLINE YET AS SOME QUESTIONS TO THE TIMING OF THE TEMPERATURE
DECREASE ETC. AT THIS TIME NOT THINKING WE WILL GET INTO WIND
CHILL WARNING CRITERIA OVER THE ENTIRE AREA...JUST SOME LOCATIONS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE MODELS CONTINUE TO JUMP BACK AND FORTH WITH INCONSISTENCY ON
TIMING THE PASSAGE OF THE ARCTIC FRONT SAT NIGHT AND THE STRENGTH OF
A POSSIBLE LOW ALONG THE FRONT. NOW THE GFS IS SHOWING MORE OF A LOW
AND SLOWER FRONTAL PASSAGE TIMING. WILL CONTINUE TO AVERAGE THE
MODELS FOR THE FORECAST WITH MAINLY LAKE EFFECT BY LATE SUN/SUN
NIGHT.
HIGH PRESSURE EXPECTED TO BE OVER THE AREA FOR DRY CONDITIONS ON
MON. ECMWF AGAIN DIGS SHARPER TROUGH WITH NEXT SYSTEM FOR TUE WITH
STRONGER LOW. ONCE AGAIN...QUESTION THIS SO WILL SIDE A LITTLE MORE
WITH GFS WHICH STILL BRINGS MOISTURE AND ANOTHER THREAT FOR SNOW
INTO THE AREA WITH LESS WARMING.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
SCATTERED SNOW SHOWERS SEEN UPSTREAM ACROSS NRN INDIANA AND LOWER
MICHIGAN WILL SPREAD EAST OVERNIGHT. VISIBILITIES WILL BRIEFLY DROP
TO MVFR AT MOST SITES WITH THE CHANCE OF SEEING SOME IFR SNOW
SHOWERS...ESPECIALLY AT CLE/ERI. A BREAK IN THE SNOW SHOWERS IS
EXPECTED LATE TONIGHT INTO WEDNESDAY MORNING BEFORE PICKING UP
AGAIN AHEAD OF THE ARCTIC COLD FRONT THAT WILL PUSH SOUTH ACROSS
THE AREA WEDNESDAY EVENING. WESTERLY WINDS WILL INCREASE AHEAD OF
THE FRONT ACROSS NW/NRN OHIO WITH GUSTS OF 20-25 KNOTS. WINDS WILL
SHIFT TO THE NW WITH THE FRONTAL PASSAGE ON WEDNESDAY EVENING.
CEILINGS WILL START OFF VFR AND DROP TO MVFR IN SNOW SHOWERS.
.OUTLOOK...NON VFR LINGERING INTO WEDNESDAY EVENING THEN MAINLY
SNOWBELT THU. NON VFR CONDITIONS RETURN FRIDAY NIGHT AND CONTINUE
INTO SUNDAY.
&&
.MARINE...
THE NEXT ARCTIC FRONT WILL GRADUALLY TURN SW WINDS TO NW LATE
TONIGHT THRU WED NIGHT. A TROUGH HANGING BACK INTO THE EASTERN LAKES
WILL KEEP THE FLOW DISRUPTED ENOUGH TO KEEP SPEEDS MOSTLY IN A 10 TO
20 KNOT RANGE UNTIL THU WHEN 15 TO 25 KNOTS MAY BE MORE COMMON. HIGH
PRESSURE CROSSES OH ON FRI TO PRODUCE A LIGHT FLOW THEN WINDS BACK
TO THE SSW FOR FRI NIGHT INTO SAT AHEAD OF THE NEXT ARCTIC FRONT
THAT SHOULD CROSS THE LAKE SAT NIGHT VEERING THE WINDS BACK TO NW AT
10 TO 20 KNOTS FOR SUN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...MULLEN
SHORT TERM...KIELTYKA
LONG TERM...ADAMS
AVIATION...KEC
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
955 PM EST TUE FEB 17 2015
.SYNOPSIS...
ARCTIC FRONT CROSSES WEDNESDAY. ARCTIC HIGH PRESSURE THURSDAY NIGHT
INTO FRIDAY. LOW PRESSURE TRACKING UP THE OHIO VALLEY WILL MAKE
FOR A METEOROLOGICAL MESS THIS WEEKEND. COLDER AGAIN BY MONDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
UPDATE...
SOME CHANGES TO DISCUSS. FIRST...KNOCKED THE FRONT END OF THE POPS
BACK A FEW HOURS. MODELS IN THE SHORT TERM ARE NOT PLAYING NICELY
RIGHT NOW WITH THE HRRR MUCH LATER THAN THE LATEST 00Z RUN OF THE
NAM. RAP ALSO FALLS ON THE LATER SIDE OF THE THINGS WITH THE HRRR.
START OF THE SNOW OVER THE WESTERN ZONES LOOKS TO BE MORE OF A 09Z
TO 12Z THING AS OPPOSED TO 06Z. NEXT...REPOPULATED THE
TEMPERATURES OVERNIGHT WITH A MODEST DROP THINKING TEMPERATURES
ARE ONLY GOING TO FALL 3 TO 7 DEGREES FROM CURRENT VALUES. KEPT
BUT REWORKED THE NON DIURNAL TREND FOR WEDNESDAY AFTERNOON THANKS
TO THE COLD FRONT PASSAGE. ALSO BUMPED THE WIND GUSTS UP WITH THE
FRONT AS WELL.
PREVIOUS DISCUSSION...
MODELS ARE IN GOOD AGREEMENT WITH ARCTIC COLD FRONT CROSSING
SOUTHEAST OH AROUND 12Z...RUSHING EAST INTO THE EASTERN MOUNTAINS
INTO THE EVENING HOURS. NAM BUFKIT SOUNDINGS ...TOGETHER WITH
HIGH PROBABILITIES FROM THE SREF MODEL SUGGEST 1 TO 3 INCHES OF
SNOW CAN OCCUR ACROSS THE LOWLANDS THROUGH THE WEDNESDAY
AFTERNOON...AND 2 TO 4 ACROSS THE EASTERN MOUNTAINS THROUGH
WEDNESDAY EVENING. THE GFS AND ECMWF MODELS ARE IN GOOD AGREEMENT
WITH THE TIMING OF PCPN IN THEIR QPF FIELDS. TEMPERATURES WILL
BE LOW ENOUGH FOR ALL PCPN TO FALL AS SNOW. THEREFORE...ISSUED A
WINTER WEATHER ADVISORY FOR SNOW FOR MOST OF THE AREA...EXCEPT FOR
THE EXTREME NORTHERN TIER OF COUNTIES SOUTHEAST OH AND WV
LOWLANDS PER COORDINATION WITH NEIGHBORING OFFICES.
WENT WITH A BLEND OF THE BIAS CORRECTED SREF AND NAM FOR
TEMPERATURES THROUGH THE PERIOD.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
ANOTHER ARCTIC FRONT WILL BE KNOCKING ON OUR DOOR EARLY WEDNESDAY
MORNING. ITS A QUICK MOVING FEATURE THAT WILL CROSS CWA FROM 12Z-18Z
WEDNESDAY. IT LOOKS VERY SIMILAR TO THE FRONT LAST
WEEKEND...ALTHOUGH WINDS DO NOT LOOK AS STRONG. THIS MEANS WE CAN
EXPECT ANOTHER ROUND OF SNOW SQUALLS WEDNESDAY...TAPERING OFF
WEDNESDAY EVENING INTO THE OVERNIGHT. ALSO EXPECT VERY SIMILAR SNOW
FALL AMOUNTS...WITH A GENERAL 1-2 INCHES ACROSS THE
LOWLANDS...EXCEPT SOME CLOSER TO 3 WHERE MORE PERSISTENT SQUALLS
TRACK. THE HIGHER ELEVATIONS OF WV SHOULD BE GENERALLY 2-4...WITH
THE POTENTIAL FOR UP TO 6 AT HIGHEST ELEVATIONS. THAT MAKES THIS
ANOTHER BORDERLINE ADVISORY EVENT ACROSS THE LOWLANDS...AND WILL
MENTION IN THE HWO. LIGHT SNOW SHOWERS AND FLURRIES EXPECTED TO
LINGER THROUGH MOST OF THE NIGHT...AND INTO THURSDAY IN THE
MOUNTAINS.
VERY COLD AIR POURS IN BEHIND THE FRONT...AND HAVE A NON DIURNAL
TREND WEDNESDAY AFTERNOON. NOT MUCH RECOVERY ON THURSDAY...AND
TRENDED TOWARD THE COLDER MAV...ENDING UP WITH MOSTLY SINGLE
DIGITS...EXCEPT STAYING BELOW 0 IN THE MOUNTAINS. STILL ENOUGH WIND
WEDNESDAY NIGHT INTO THURSDAY TO PRODUCE LOW WIND CHILL VALUES. WILL
CONTINUE MENTION OF POSSIBLE ADVISORY IN HWO.
HIGH PRESSURE BEGINS MOVING IN FROM THE WEST LATER THURSDAY...AND
WHILE THIS WILL CAUSE THE WINDS TO SLACKEN...IT WILL ALSO START
BREAKING UP THE CLOUDS. THIS SETS THE STAGE FOR THE COLDEST NIGHT SO
FAR THIS SEASON THURSDAY NIGHT. THE COMBINATION OF PLENTY OF SNOW ON
THE GROUND...AND CLEAR SKIES WILL CREATE IDEAL RADIATIONAL COOLING.
HAVE EVERYONE DROPPING BELOW 0 THURSDAY NIGHT.
THE HIGH MOVES TO THE EAST FRIDAY...WITH WARM AIR ADVECTION STARTING
AHEAD OF THE NEXT SYSTEM. STILL A GOOD AMOUNT OF SUNSHINE FRIDAY AS
WELL...BUT WILL BE ANOTHER CHILLY DAY WITH HIGHS IN THE TEENS AND
LOW 20S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
RIGOROUS FCST PROCESS FOR THIS PERIOD...WHICH STARTS WITH ARCTIC
HIGH PRESSURE EXITING. H85 TEMPERATURES SKYROCKET FROM -25C FRI
MORNING TO -12C FRI EVENING TO START THIS PERIOD...TO -2C 12Z SAT
EVENTUALLY TO 5C SUN ON 60-70 KT SW FEED. THIS HAPPENS AS HEIGHTS
RISE DRAMATICALLY ON RAPID EXODUS OF DEEP UPPER LEVEL TROUGH...WHICH
ALSO ALLOWS LOW PRESSURE TO TRACK UP THE OHIO VALLEY. THE GULF
ACTUALLY BECOMES WIDE OPEN ON ACCOUNT OF THE GRADIENT BETWEEN THE
ARCTIC HIGH PASSING BERMUDA AND THE LOW TRACKING UP THE OHIO VALLEY.
THIS SPELLS TWO THINGS...SNOW TO SLEET AND FREEZING RAIN CREATING
HAZARDOUS TRAVEL OVERNIGHT FRI NT INTO SAT...AND THEN POTENTIALLY
HEAVY RAINFALL SAT INTO SUN.
GIVEN THE OTHER MODELS ARE COMING IN LINE WITH THE GFS...RELIED
LARGELY ON THE GFS / WPC FOR TEMPERATURES DURING THE WEEKEND
SYSTEM...THOUGH ALSO BLENDED IN THE BIAS CORRECTED ECMWF FOR PEAK
TEMPERATURES ON SUN...AND THEN THE GFS FOR TEMPERATURES IN THE WARM
NOSE ALOFT. THIS SPELLS SNOW OVERSPREADING THE AREA FRI
NT...TRANSITIONING TO SLEET AND THEN FREEZING RAIN SAT...AND THEN
PLAIN RAIN SAT AFTERNOON AND EVENING. THE MIXED PRECIPITATION IS
LIKELY TO HOLD ON IN THE NRN WV MOUNTAINS EVEN INTO SUN...WHEN THE
COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM TURNS THE FLOW TO
THE W AND FINALLY SCOURS OUT THE OLD LOW LEVEL COLD AIR. MIXED
PRECIPITATION MAY ALSO HANG ON ALONG WRN FRINGES OF THE FCST AREA IF
THE SFC LOW DOES NOT TRACK TOO FAR W OF THE OHIO RIVER.
MODELS GENERATE 1 TO 3 INCHES TOTAL LIQUID PRECIPITATION
WHICH...WITH THE SNOW COVER...DEW POINTS ABOVE FREEZING AND
WIND...COULD LEAD TO WATER ISSUES SAT NT INTO SUN. DEW POINTS WILL
BE HIGHEST ACROSS THE S...WHERE THERE WAS THE MOST SNOW...PEAKING IN
THE 40 TO 45F RANGE SUN JUST AHEAD OF THE COLD FRONT. THIS IS WHERE
THE GFS SOLN IS THE MOST WORRISOME. IT IS NOT ONLY THE WETTEST ONE
WITH THE 3 INCH LIQUID TOTAL...BUT IT PLACES THAT MAXIMUM TOTAL IN
AN AXIS ACROSS THE S.
THE PRECIPITATION SWITCHES BACK TO FREEZING RAIN...SLEET AND THEN
SNOW IN AN ANAFRONT MANNER SUN NT...WINDING DOWN AS SNOW SHOWERS MON
INTO MON NT. COLD HIGH PRESSURE PASSES QUICKLY OVERNIGHT MON NT.
THE GFS AND ECMWF ARE AT ODDS WITH THE SWD PROGRESS OF THE NEXT
ARCTIC FRONT TUE DAY 7...THE GFS SOLN BEING THE COLDEST.
WILL INTRODUCE HIGHLIGHTS FOR WINTER AND WATER THREATS IN THE HWO.
HIGHS AND LOWS INCLUDING THE WEEKEND SYSTEM ARE CLOSE TO WPC.
EMPLOYED THE GFS FOR DAY 7 NT...THE LOWEST AVAILABLE GUIDANCE BUT
STILL HIGHER THAN ISC...THIS DEPENDS UPON THE TIMING AND PROGRESS OF
THAT LAST FRONT.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
VFR TONIGHT.
SNOW ARRIVES WITH THE NEXT ARCTIC COLD FRONT AFTER 10Z WEDNESDAY.
VISIBILITIES DROP TO IFR NO LATER THAN AN HOUR AFTER SNOWFALL
STARTS. EXPECT OBSERVATIONS TO BOUNCE BETWEEN LIFR AND IFR IN THE
SNOWFALL AS INTENSITIES FLUCTUATE. TERMINALS ACROSS THE WEST WILL
IMPROVE AFTER 20Z...WHILE EASTERN TERMINALS MAY NOT IMPROVE BY 00Z
THURSDAY.
WINDS VEER BEHIND THE COLD FRONT TO 20 TO 25 KNOT GUSTS OUT OF
THE WEST TO THE WEST NORTHWEST.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...
FORECAST CONFIDENCE: HIGH TONIGHT. MEDIUM AFTER 10Z WEDNESDAY.
ALTERNATE SCENARIOS: THE ONSET AND INTENSITY OF SNOW MAY VARY
ALONG THE FRONT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 02/18/15
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08
CRW CONSISTENCY H H H H H H M H H H H M
HTS CONSISTENCY H H H H H H H H M L H H
BKW CONSISTENCY H H H H H H M H M H H M
EKN CONSISTENCY H H H H H H H H H M M M
PKB CONSISTENCY H H H H H H H H H M H H
CKB CONSISTENCY H H H H H H H H H H M H
AFTER 00Z THURSDAY...
IFR POSSIBLE AGAIN IN SNOW SHOWERS WITH ARCTIC FRONT WEDNESDAY
AFTERNOON AND EVENING...MAINLY OVER HIGHER ELEVATIONS. IFR POSSIBLE
IN MIXED WINTRY PRECIPITATION AND RAIN THIS WEEKEND.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 7 AM TO 7 PM EST WEDNESDAY FOR
WVZ015>018-024>030-033>039-046-047.
WIND CHILL WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY MORNING
FOR WVZ033>038-046-047.
WINTER WEATHER ADVISORY FROM 1 AM TO 1 PM EST WEDNESDAY FOR
WVZ005>009-013-014.
OH...WINTER WEATHER ADVISORY FROM 1 AM TO 1 PM EST WEDNESDAY FOR
OHZ075-083>087.
KY...WINTER WEATHER ADVISORY FROM 1 AM TO 1 PM EST WEDNESDAY FOR
KYZ101>103-105.
VA...WINTER WEATHER ADVISORY FROM 7 AM TO 7 PM EST WEDNESDAY FOR
VAZ003-004.
WIND CHILL WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY MORNING
FOR VAZ003-004.
&&
$$
SYNOPSIS...ARJ/TRM/JMV
NEAR TERM...ARJ/26
SHORT TERM...JMV
LONG TERM...TRM
AVIATION...26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
524 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC OBS AND WEB CAMS INDICATE LIGHT SNOW HAS OVERSPREAD PORTIONS
OF SOMERSET...BEDFORD AND FULTON COUNTIES AS OF 22Z. LIGHT SNOW
WILL MARCH NORTHWARD OVERNIGHT...AS SFC WAVE PASSES SOUTH OF PA.
LATEST 4KM NAM AND HRRR SUGGESTS THE SNOW WILL GET TO ARND I-80
BY 03Z...THEN REACH IT/S NORTHERNMOST EXTENT ACROSS THE N MTNS BY
MIDNIGHT.
BEST 850-700MB FRONTOGENETIC FORCING IN MDLS SUGGESTS THE AXIS OF
HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD BORDER...WITH PERHAPS FAR
SRN LANCASTER-YORK COUNTIES PICKING UP SLIGHTLY HIGHER AMOUNTS AS
THE BEST WARM ADVECTION/FRONTOGENESIS MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER...LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL. BLENDED MDL QPF CONTINUES TO INDICATE ONLY ARND 0.20
INCHES ACROSS THE S TIER...WITH ALMOST NOTHING OVR THE N MTNS.
HOWEVER...AN EXAMINATION OF MDL TIME SECTIONS INDICATES NEARLY ALL
LIFT WITHIN THE CLOUD LAYER FALLS WITHIN THE DENDRITIC GROWTH
ZONE...IMPLYING A HIGH SNOW/WATER RATIO OF CLOSE TO 20 TO 1.
THEREFORE...SNOW TOTALS OF NR 4 INCHES STILL SEEM PROBABLE ALONG
THE MD BORDER.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 4 INCHES
OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE LESSER AMOUNTS OF
AROUND AN INCH ARE ANTICIPATED ALONG INTERSTATE 80 AND PERHAPS
A DUSTING OVR THE N MTNS.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
STILL VFR...BUT EXPECT CONDITIONS TO DO DOWN FAST ONCE SNOW
STARTS...GIVEN THE DRY AIRMASS.
MINOR ADJUSTMENTS MADE TO 21Z TAFS.
EARLIER DISCUSSION BELOW.
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ024>028-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...GARTNER
AVIATION...LA CORTE/MARTIN
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
433 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND
MOVING INTO NORTHERN WV-WESTERN VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS BETWEEN ABOUT
20-23Z POTENTIALLY IMPACTING THE EVENING COMMUTE.
LOOKING AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM
SUGGESTS THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD
BORDER...WITH PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP
SLIGHTLY HIGHER AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS
MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-4 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
STILL VFR...BUT EXPECT CONDITIONS TO DO DOWN FAST ONCE SNOW
STARTS...GIVEN THE DRY AIRMASS.
MINOR ADJUSTMENTS MADE TO 21Z TAFS.
EARLIER DISCUSSION BELOW.
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ024>028-
033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...GARTNER
AVIATION...LA CORTE/MARTIN
CLIMATE...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
352 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND
MOVING INTO NORTHERN WV-WESTERN VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS BETWEEN ABOUT
20-23Z POTENTIALLY IMPACTING THE EVENING COMMUTE.
LOOKING AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM
SUGGESTS THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD
BORDER...WITH PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP
SLIGHTLY HIGHER AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS
MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-4 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR PAZ024>028-033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...GARTNER/DEFLITCH
AVIATION...LA CORTE
CLIMATE...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
206 PM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /THROUGH TONIGHT/...
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND
MOVING INTO NORTHERN WV-WESTERN VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS BETWEEN ABOUT
20-23Z POTENTIALLY IMPACTING THE EVENING COMMUTE.
LOOKING AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM
SUGGESTS THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD
BORDER...WITH PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP
SLIGHTLY HIGHER AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS
MOVES THROUGH OVERNIGHT.
SREF/GEFS SUPPORT CONFINING QPF OF HALF INCH OR MORE SOUTH OF THE
BORDER LEADING TO A HIGH CONFIDENCE OF A MAINLY LIGHT-MODERATE
SNOWFALL.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-4 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
PRECIP WILL BE TAPERING OFF IN THE HOURS JUST AFTER MIDNIGHT OVER
MY SWRN ZONES WITH MOST OF THE SNOW HAVING ENDED EVEN IN THE EAST
BY AROUND SUNRISE.
OVERNIGHT LOWS WILL AVERAGE IN THE SINGLE DIGITS...TO PERHAPS THE
LOWER TEENS OVER THE SE.
&&
.SHORT TERM /TUESDAY/...
THE BROAD AREA OF WEAK TO MDT ASCENT ASSOCIATED WITH THE COUPLED
UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY MORNING
FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...ALLOWING FOR SOME PARTIAL CLEARING IN THE AFTERNOON.
I FOLLOWED MOS POPS MOST CLOSELY LEADING TO A MAINLY DRY DAY FCST
FOR MOST AREAS. THINKING IS THAT ANY LINGERING LIGHT SNOW SHOWERS
WILL BE CONFINED TO WESTERN HIGHER ELEVATIONS.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10 DEG COMPARED
TO TODAY`S HIGHS. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15-20 DEG BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR WITH NO SIG WX CONDITIONS THROUGH LATE AFTERNOON.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST OVERNIGHT
WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2 OF THE
AIRSPACE LATER THIS AFTERNOON AND OVERNIGHT. SNOW WILL BE QUICK-
HITTING AND END BY 12-15Z TUESDAY FROM WEST TO EAST. HIGHEST
CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND OF HIGH
RES MDLS FOR TIMING WITH SNOW ONSET 21-00Z SPREADING FROM SW TO
NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
SAT...MVFR WITH SNOW SHOWERS ASSOC WITH AN APPROACHING COLD FRONT.
&&
.CLIMATE...
MOST OF THE FORECAST AREA WAS ZERO OR COLDER LAST NIGHT WITH
CHANDLER`S VALLEY BEING THE COLDEST COMING IN AT -32.
HARRISBURG AND WILLIAMSPORT BOTH TIED THEIR RECORD LOWS FOR THE
DATE. HARRISBURG WAS 0 AND WILLIAMSPORT WAS -5.
RECORD LOWS/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905
STATE COLLEGE.........-8/1904
YORK..................-7/1963
ALTOONA...............-2/2004
BRADFORD..............-23/1943
CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943
LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR PAZ024>028-033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE
CLIMATE...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1042 AM EST MON FEB 16 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF THE REGION TONIGHT AND EARLY
TUESDAY FOLLOWED BY ANOTHER BLAST OF ARCTIC AIR THAT WILL MOVE
INTO THE REGION FOR THE MID TO LATE WEEK PERIOD.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER LOW AND THE CORE OF COLDEST AIR WILL BE LIFTING OUT OF THE
AREA EARLY TODAY.
COLDEST TEMP SO FAR WAS -32 AT CHANDLER`S VALLEY.
SATELLITE LOOP SHOWS CLOUDS CONTINUING TO INCREASE OVER THE REGION
WITH SURFACE OBS SHOWING THE NEAREST SNOW HITTING THE GROUND FROM
SOUTHERN OHIO DOWN INTO CENTRAL WEST VA.
LATEST HRRR HAS LIGHT SNOW OVERSPREADING SWRN AREAS DURING THE
LATTER HALF OF THE AFTERNOON INTO THE EVENING. THE EVENING COMMUTE
COULD BECOME SLIPPERY OVER MY SWRN ZONES WITH SNOW EXPECTED TO
BEGIN IN THE 21-00Z/4-7PM TIMEFRAME.
I NUDGED SNOW AMOUNTS DOWN A BIT TO FIT LATEST GUIDANCE. LOOKING
AT THE BEST LAYER FRONTOGENETIC FORCING FROM THE NEW NAM SUGGESTS
THE AXIS OF HEAVIEST SNOW WILL BE SOUTH OF THE PA-MD BORDER...WITH
PERHAPS FAR SRN LANCASTER-YORK COUNTIES PICKING UP SLIGHTLY HIGHER
AMOUNTS AS THE BEST WARM ADVECTION/FRONTOGENESIS MOVES THROUGH
OVERNIGHT.
WILL CONTINUE THE WINTER WEATHER ADVISORY WITH NO PLANNED CHANGES
AT THIS POINT IN TIME...FOR THE SOUTHERN 2 LAYERS OF COUNTIES IN
OUR CWA. THE SOUTHERN TIER IS EXPECTED TO SEE BETWEEN 2 AND 5
INCHES OF SNOW BY THE MORNING COMMUTE TUESDAY...WHILE COUNTY-
LAYER WITHIN THE RT 22/322 CORRIDOR SHOULD SEE MORE ALONG THE
LINES OF 1-3 INCHES. LESSER AMOUNTS OF AROUND 1-2 INCHES ARE
ANTICIPATED TO FALL RIGHT ALONG INTERSTATE 80...WITH AN INCH OR
LESS ACROSS THE MTNS OF NRN PENN.
HIGH TEMPS TODAY WILL REBOUND TO NEAR 10 ACROSS THE NORTHERN
MOUNTAINS...AND REACH THE MID TO UPPER TEENS IN FAR S-CENT AND
SOUTHEASTERN PA.
&&
.SHORT TERM /TUESDAY/...
THE BROAD AREA OF WEAK TO MDT DEEP-LAYER UVVEL ASSOCIATED WITH THE
COUPLED UPPER JET WILL SCOOT QUICKLY EAST OF THE REGION TUESDAY
MORNING FOLLOWED BY WEST-SOUTHWESTERLY FLOW IN THE LOW TO MID
LEVELS...WITH PARTIAL CLEARING IN THE AFTERNOON.
TEMPS DURING THE DAY TUESDAY WILL WARM BY ANOTHER 10F /COMPARED
TO TODAY`S HIGHS/. IT`S PRETTY AMAZING THAT EVEN AFTER THE
UPCOMING 2 DAYS OF MODERATING TEMPS...HIGHS TUESDAY WILL STILL BE
15 DEG F BELOW NORMAL FOR THE DATE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
VERY COLD AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST
THE UPCOMING WORK-WEEK AS A STRONG UPPER LEVEL RIDGE REMAINS OVER
THE WESTERN U.S. AND CONTINUES TO DIRECT POLAR AIR INTO THE
EASTERN U.S. VIA PERSISTENT TROUGH.
SHORT WAVE ENERGY IS FORECAST TO CROSS THE INTO THE PAC LATE IN
THE WEEK AND DIG INTO THE FOUR CORNERS REGION AS THE UPPER RIDGE
REBUILDS NWD INTO WRN CANADA. THIS WILL SHIFT THE UPPER TROF AXIS
NOW COVERING THE EASTERN U.S. - WESTWARD. THIS IN TURN WILL LEAD
TO A FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST NEXT WEEKEND
AND A MODERATION AWAY FROM THE BITTER COLD IN THE CURRENT PATTERN.
PRIOR TO THIS LATE WEEK...LARGE SCALE FLOW MODIFICATION WE`LL HAVE
TO DEAL WITH ONE MORE ARCTIC BLAST...THE LEADING EDGE OF WHICH
WILL PUSH ACROSS THE STATE DURING THE DAY WEDNESDAY. SOMEWHAT
SIMILAR TO SATURDAY...WE SEE A WELL-DEFINED AREA OF STEEP 850-500
MB LAPSE RATES AROUND...OR IN EXCESS OF 7C/KM THAT WILL MOVE
ACROSS THE WESTERN MTNS DURING THE EARLY TO MID AFTERNOON...AND
THROUGH THE SUSQ VALLEY EARLY WED EVENING. ALTHOUGH LIKELY NOT AS
EXTENSIVE AND CONSISTENTLY INTENSE OF A LINE THAT WE SAW SATURDAY
/COMPLETE WITH FEW FLASHES OF LIGHTNING IN SOME LOCATIONS/...THE
SQUALLS ASSOCIATED WITH THIS RIBBON OF INSTABILITY WED WILL LIKELY
COME IN THE FORM ONE OR TWO LINES...AND DUMP A QUICK .5 TO 1.5
INCHES OF SNOW - GREATLY IMPACTING TRAVEL FOR A SHORT PERIOD.
BEHIND THIS SYSTEM YET ANOTHER SURGE OF EXTREMELY COLD AIR WILL
SURGE ACROSS THE STATE FOR THE SECOND HALF OF THE WEEK.
SIMILAR...EXTREMELY COLD TEMPS AT 850 MB ARE FORECAST TO MOVE OVER
THE STATE THURSDAY AND FRIDAY /AND COULD BE EVEN A FEW DEG C LOWER
THAN THOSE ASSOCIATED WITH THIS PAST SUNDAY-MONDAY ARCTIC
AIRMASS/. 03Z SREF SHOWS MEAN 850 TEMPS OF -25 TO -28C COVERING
ALL OF CENTRAL PENN WHICH IS ABOUT -3 SIGMA. HIGH TEMPS THURSDAY
MAY STAY A FEW-SVRL DEG F BELOW ZERO AGAIN ACROSS THE NRN
MTNS...AND HOLD IN THE SINGLE DIGITS TO LOWER TEENS ACROSS THE
REST OF CENTRAL AND SRN PENN...BEFORE MODERATING BY 5-7 DEG
FRIDAY. MORNING LOWS THURSDAY AND FRIDAY COULD RIVAL THOSE OF
SUNDAY AND MONDAY MORNING.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES NEXT SUNDAY...HOWEVER...HOLD THE POTENTIAL TO RISE
ABOVE THE FREEZING MARK OVER A GOOD PART OF CENTRAL PA AS THE
EARLIER MENTIONED MODERATION IN THE UPPER FLOW IS FORECAST TO
ARRIVE. THE NEXT SHORTWAVE TROF IS ALSO CURRENTLY TIMED FOR NEXT
WEEKEND...LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE
OVER SRN PA AND SNOW OVER THEN NORTH.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
VFR WITH NO SIG WX CONDITIONS THROUGH THE AFTERNOON. INCR MID-HIGH
CLOUDS AOA 12KFT AGL. WINDS FROM 280-320 WILL CONTINUE TO
DIMINISH BCMG LGT AND VRB AS SFC HIGH PRESSURE DRIFTS OVER THE
AIRSPACE.
LOW PRESSURE MOVING NEWD FROM AL OFF THE MID ATLC COAST
BTWN 00-12Z TUE WILL SPREAD SNOW AND IFR CONDS ACROSS THE SRN 1/2
OF THE AIRSPACE LATER THIS AFTERNOON INTO THE OVERNIGHT. SNOW
WILL BE QUICK- HITTING AND END BY 15-18Z TUE FROM WEST TO EAST.
HIGHEST CONFIDENCE IN IFR IS OVER THE SRN AIRFIELDS. USED A BLEND
OF HIGH RES MDLS FOR TIMING WITH -SN ONSET 21-00Z SPREADING FROM
SW TO NE.
OUTLOOK...
WED-THU...MVFR/IFR -SHSN WRN 1/3. VFR/MVFR -SHSN CENTRAL/ERN 2/3
FRI...BCMG VFR. NO SIG WX.
&&
.CLIMATE...
RECORD LOW TEMPERATURES FOR 2/16 IN JEOPARDY AT MANY SITES.
CHANDLER VALLEY COOP REPORTED -32F AT 0645 AM. TO PUT THE EXTREME
COLD INTO PERSPECTIVE...THE PA STATE RECORD LOW IS -42F AT
SMETHPORT ON 1/5/1904.
RECORD LOW/YEAR
HARRISBURG.............0/1905
WILLIAMSPORT..........-5/1905 STATE COLLEGE.........-8/1904
YORK..................-7/1963 ALTOONA...............-2/2004
BRADFORD..............-23/1943 CLEARFIELD............-6/1930
JOHNSTOWN.............-10/1943 LANCASTER.............+2/1987
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR PAZ024>028-033>036-056-057-059-063>066.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE/STEINBUGL
CLIMATE...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
106 PM EST MON FEB 16 2015
.SYNOPSIS...
A MOIST LOW PRESSURE SYSTEM WITH WIDESPREAD WINTRY PRECIPITATION
WILL TRACK ACROSS THE CAROLINAS TONIGHT AND MOVE OFF THE MID
ATLANTIC COAST TUESDAY MORNING. IN ITS WAKE...AN ARCTIC COLD FRONT
WILL SWEEP THROUGH FROM THE NORTH WEDNESDAY. VERY COLD HIGH
PRESSURE WILL THEN BUILD IN AND PERSIST THROUGH FRIDAY...BEFORE A
MOIST SURFACE BOUNDARY MOVES INTO THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 1255 PM EST...THE UPPER LEVEL SHORTWAVE MOVING FROM THE SRN
PLAINS TO THE MID MS RIVER VALLEY TODAY WILL DAMPEN AS IT MOVES
EASTWARD ACROSS THE APPALACHIANS LATER TONIGHT. THE ASSOCIATED SFC
LOW CENTER MOVING ACROSS THE DEEP SOUTH SHOULD TRACK FROM THE
CENTRAL AL/GA BORDER AT 00Z THIS EVENING...TO NW OF AUGUSTA GA BY
06Z...TO OFF THE OUTER BANKS OF NC BY 12Z TUE. AHEAD OF THIS
LOW...PRECIPITATION IS RAPIDLY FILLING IN FROM THE WEST THIS
AFTN...AND THERMAL PROFILES ARE QUICKLY WET BULBING DOWN TO SUPPORT
MAINLY SNOW/SLEET SHORTLY AFTER ONSET. THE DEEPER FORCING WILL REACH
THE FORECAST AREA FROM THE W STEADILY THROUGH THE LATE AFTN
HOURS...MAXIMIZING 00Z TO 03Z AS THE BEST SRLY JET TRAVERSES THE
REGION. THE LATEST RAP RUN HAS REGAINED IT/S THERMAL SANITY
SOMEWHAT...WITH SUBFREEZING SFC TEMPS NOW LARGELY LOCKED IN ALONG
AND NW OF INTERSTATE 85 UNTIL MID TO LATE EVENING. THE MAIN
EXCEPTION WILL BE IN WRN/SRN UPSTATE SECTIONS AS WELL AS NE GA
OUTSIDE OF THE MTNS...WHERE THE SREF MEAN/GEFS ALSO SUPPORT EARLIER
WARMING OF SFC TEMPS. THIS WILL MAKE FOR A VERY SHARP ICE ACCUM
GRADIENT IN THE SRN TIER...BUT THE CURRENT HAZARD SUITE SEEMS TO
HAVE THIS FAIRLY WELL PLACED.
LOCATIONS NW OF INTERSTATE 40 LOOK TO BE MORE SOLIDLY SNOW
THROUGHOUT THE VAST MAJORITY OF THE EVENT...WITH SOME SLEET ONLY
MIXING IN AT TIMES EARLY AND LATE...AND ANY FZRA WINDOW FAIRLY
BRIEF. NRN BLUE RIDGE AREA SNOW ACCUMS HAVE BEEN BOOSTED SLIGHTLY.
EXPECT SOME DRY SLOTTING TO ARRIVE AT MID LEVELS CIRCA 06Z TO
09Z...WITH POPS TRENDING DOWN WEST TO EAST LATE TONIGHT. NW FLOW
MOISTURE WILL DIMISH ALONG THE SPINE OF THE SRN APPALACHIANS TUE
MORNING...WITH LOW LEVEL FLOW BACKING AHEAD OF THE FALLING HEIGHTS
TO THE W AS A DEEP CENTRAL CONUS TROUGH TRANSITIONS EWD. MELTING IS
LIKELY IN THE SRN MTNS AND ACROSS THE FOOTHILLS/PIEDMONT TUE
AFTN...TEMPS REBOUNDING ABOVE FREEZING IN WEAK WESTERLY DOWNSLOPE
FLOW.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...THE 00Z MODELS ARE IN VERY GOOD AGREEMENT ON
THE BACK EDGE OF THE PRECIP SHIELD PRETTY MUCH COMPLETELY EXITED OFF
TO THE EAST BY 12Z TUESDAY...EXCEPT FOR SOME LINGER NW FLOW CHCS FOR
TUESDAY MORNING. OTHERWISE...TUESDAY LOOKS LIKE A COLD DAY...WITH
PERSISTENT 850 MB CAA ALL DAY. TEMPS DO REBOUND FROM SUN-MON
READINGS...BUT STILL 10-15 DEG BELOW NORMAL (20S TO UPR 30S MTNS AND
MAINLY LWR-MID 40S PIEDMONT).
TUESDAY NIGHT THRU WEDNESDAY NIGHT...ANOTHER PIECE OF THE POLAR
VORTEX WILL DIG INTO THE GREAT LAKES...AND BRING TWO SHOTS OF
REINFORCING ARCTIC AIR. THE FIRST WILL BE WEDNESDAY MORNING...WITH
STRONG CAA AND SOME LLVL MOISTURE FOR NW FLOW SNOW SHWR ACTIVITY.
THE SECOND (STRONGER) FRONT WILL CROSS THE AREA WEDNESDAY NIGHT. THE
MAIN CONCERN WITH THE FIRST FRONT WILL BE SNOW ALONG THE TN BORDER.
GUIDANCE HAS TRENDED A LITTLE WETTER...BUT LIKE THE LAST FEW FRONTS
OF THIS NATURE...THE TIME INTERVAL IS RATHER SHORT...AND GENERALLY
SUB-ADV ACCUMS ARE EXPECTED. I DID BUMP UP POP FOR WEDNESDAY IN THE
NC MTNS. THE OP MODELS AGREE ON STEEP LLVL LAPSE RATES ACRS THE
PIEDMONT WITH AT LEAST A SLGT CHC OF A FEW SHWRS BREAKING
CONTAINMENT FROM THE TN LINE WED AFTN. I INTRODUCED A SLGT CHC OF
SNOW SHWRS ACRS THE NC PIEDMONT. NO ACCUMS EXPECTED...BUT AN ISOLD
DUSTING LOOKS POSSIBLE. TEMPS WEDNESDAY WILL BE 2-3 CATEGORIES
COLDER THAN TUESDAY. WITH THE SECOND FRONT WEDNESDAY NIGHT...THE
BIGGER CONCERN WILL BE WIND CHILLS. THE 850 MB TEMPS PLUMMET TO -17
TO -24C ACRS MOST OF THE CWFA. WITH STILL DECENT WINDS OF 30-40 KTS
AT 850 MB AND CAA...SHUD SEE GUSTY WINDS LINGERING OVERNIGHT IN THE
MTNS AND A LIGHT WIND ACRS THE PIEDMONT. THIS COUPLED WITH LIKELY
RECORD LOW TEMPS THURSDAY MORNING WILL RESULT IN SOLID WIND CHILL
ADV CRITERIA ACRS NEARLY THE ENTIRE CWFA...AND WIND CHILL WARNING
ACRS ALL THE NC MTNS ABOVE 3500 FT. WILL HIGHLIGHT DANGEROUS WIND
CHILLS IN THE HWO. FOR THE DAILY RECORD LOWS FOR THURSDAY SEE
CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...ONLY A FEW CHANGES WERE MADE THE PREVIOUS FCST
AS GUIDANCE CONTINUES TO SHOW UNCERTAINTY WITH THE EVOLUTION OF THE
SRN STREAM SFC BNDRY AND DEGREE/PLACEMENT OF SFC CYCLOGENESIS. THERE
SHOULD BE A GOOD AMOUNT OF GOM MOISTURE FLUX AFT THU BUT AGAIN...AN
AGREEABLE AREA OF LIKELY PRECIP REMAINS TO BE WORKED OUT.
WITH A VERY COLD START TO THE DAY THU AND A CA HIGH CENTER WORKING
ACROSS TN...MAX TEMPS WILL RECOVER ONLY NOMINALLY EVEN WITH VERY
GOOD INSOL. RECORD LOW MAXES ARE STILL FCST/D BY A FEW DEGREES. THU
NIGHT AND FRI WILL REMAIN QUITE COLD AS THE SFC HIGH SHIFTS EAST
ACROSS SRN VA AND ENABLES GOOD RAD COOLING AND A SLOWLY VEERING FLOW.
THUS...MINS AND MAXES WILL AGAIN APPROACH AND POSSIBLY BREAK RECORD
LEVELS. SEE THE CLIMATE SECTION OF THIS AFD FOR THE ACTUAL RECORD
VALUES. VERY COLD WIND CHILLS WILL DEVELOP THU NIGHT ACROSS THE
FCST AREA...WITH THE NC MTNS LIKELY REACHING WARNING/ADV CRITERIA
THROUGH DAYBREAK.
THE PATTERN REMAINS ACTIVE FRI THROUGH THE WEEKEND. HOWEVER...MORE
UNCERTAINTY ARISES...WITH THE OP MODELS CONTINUING TO SHOW DISPARATE
HANDLINGS WRT THE SRN BNDRY AND INTERACTIONS WITH ULVL S/W ENERGY.
THE LATEST TREND HAS BEEN FOR A SLOWER ADVANCEMENT EAST WITH
MEASURABLE PRECIP FRI AS A STUBBORN CA HIGH PERSISTS OVER THE
CAROLINAS. THE ECMWF HAS MORE RIDGING ALOFT AND THIS KEEPS IT/S SFC
BNDRY MORE NORTH AND WEST THAN THE GFS THROUGH THE PERIOD. SO...POPS
WERE ADJ DOWN A LITTLE ACCOUNT FOR HIGHER UNCERTAINTY MAINLY ACROSS
THE SRN ZONES. PRECIP SHOULD BE MAINLY DIURNAL RAIN/SNOW...WITH SOME
LOW SNOW ACCUMS POSSIBLE OUTSIDE THE MTNS FRI NIGHT AND AGAIN
NON/MTN -SNSH POSSIBLE SAT NIGHT OVER THE NRN ZONES. MAX TEMPS
SHOULD WARM 8-10 DEGREES BOTH SAT AND SUN...YET STILL A COUPLE
DEGREES BELOW NORMAL SUN AFTERNOON.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AT KCLT...RADAR SHOWS THE LIGHT VIRGA/PRECIP SHIELD JUST WEST OF
KGSP AT ISSUANCE TIME...WITH A LIGHT SN/PL ONSET LIKELY BY 21Z AT
KCLT. EXPECT MVFR CIGS TO QUICKLY SET UP...WITH A STEADY TRANSITION
TO FZRA FOR THE BULK OF THE PRECIP EVENT TONIGHT. ICE ACCUMULATIONS
OF ONE QUARTER TO ONE THIRD INCH TONIGHT WILL POSE MAJOR DEICING
ISSUES FOR THE AIRFIELD WITH MIN TEMPS BELOW FREEZING UNTIL MID
MORNING TUE. EXPECT IFR TO LIFR CIGS DURING THE HEAVIEST
PRECIP...WITH ONLY SLOW RECOVERY THROUGH TUE MORNING. ESE WINDS
EARLY WILL QUICKLY TOGGLE NE AS THE PRECIPITATION GETS
STARTED...WITH MORE LIGHT N TO NW FLOW ON TUE AS CIGS SLOWLY LIFT
AND SCATTER.
ELSEWHERE...THE LEADING EDGE OF THE PRECIP SHIELD WAS FROM KAVL TO
KGSP TO KAND AT ISSUANCE TIME...WITH MAINLY SNOW/SLEET AT ONSET.
KAND WILL TRANSITION TO RAIN THE QUICKEST THIS EVENING...WHILE
KGSP/KGMU GET MORE LOCKED IN WITH FZRA FOR MUCH OF THE LATE
DAY/EVENING HOURS. KAVL WILL SEE MORE SNOW/SLEET FOR A LONGER
PERIOD...BEFORE THE FZRA WINDOW OPENS THERE LATE EVENING. KHKY WILL
ALSO SEE A MUCH LONGER SNOW/SLEET WINDOW...WITH LARGER ACCUMS
POSSIBLE THAN AT THE OTHER SITES...AND SLIGHTLY LESS FZRA. ALL
TOLD...MOST OF THE SITES WILL HAVE SIGNIFICANT DEICING
ISSUES...ASIDE FROM POSSIBLY KAND WHERE RAIN IS MORE LIKELY. EXPECT
CIGS TO TRANSITION DOWN QUICKLY THROUGH MVFR LATE TODAY...WITH IFR
TO LIFR LIKELY DURING THE PERIOD OF HEAVIEST PRECIPITATION THIS
EVENING/OVERNIGHT. SLOW LIFTING AND SCATTERING IS EXPECTED THROUGH
TUE MORNING.
OUTLOOK...A WEAK WAVE WILL MOVE THROUGH THE REGION ON WED...BUT
CONDITIONS LOOK TO BE MAINLY VFR. VERY COLD WEATHER WILL RETURN
THROUGH LATE WEEK.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 74% HIGH 100% HIGH 100% HIGH 100%
KHKY MED 77% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
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
&&
.CLIMATE...
RECORD MINIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 9 1958
CLT 8 1958
AVL 7 1958
RECORD LOW MAXIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 30 1900
CLT 34 1958
AVL 25 1958
RECORD MINIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 13 1903
CLT 13 1896
AVL 10 1979
RECORD LOW MAXIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 34 1947
CLT 32 1947
AVL 26 1979
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR GAZ010-017.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR GAZ018.
NC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR NCZ033-035>037-
048>053-056>059-062>065-068>072-082-501>510.
SC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR SCZ001>003-
005>009.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ004-010-
012>014.
&&
$$
SYNOPSIS...DEO
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...SBK
AVIATION...HG
CLIMATE...
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1027 AM EST MON FEB 16 2015
.SYNOPSIS...
A MOIST LOW PRESSURE SYSTEM WILL TRACK THROUGH THE SOUTHEAST STATES
TODAY SPREADING WINTRY PRECIPITATION ACROSS THE FORECAST AREA INTO
EARLY TUESDAY. IN ITS WAKE...AN ARCTIC COLD FRONT WILL SWEEP THROUGH
FROM THE NORTH WEDNESDAY. COLD HIGH PRESSURE WILL THEN BUILD IN AND
PERSIST THROUGH FRIDAY...BEFORE A MOIST SURFACE BOUNDARY MOVES INTO
THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 AM EST...THE SFC LOW CENTER WAS ANAYLYZED OVER THE LOWER
MS RIVER VALLEY...WITH A LARGE PRECIPITATION SHIELD EXTENDING NWD
ACROSS THE MID SOUTH INTO THE OH VALLEY. A BROAD AREA OF HEAVY ICING
HAS DEVELOPED ACROSS WRN AND CENTRAL TN AND THIS WILL CONTINUE TO
MOVE EASTWARD TOWARD/INTO THE SRN APPALACHIANS THROUGH EARLY AFTN.
THE MAIN POINTS OF CONCERN FOR THE FORECAST INCLUDE...SLIGHTLY MORE
BREAKS IN CLOUDS ACROSS THE FORECAST AREA THIS MORNING ALLOWING
TEMPS TO RUN A FEW DEGREES ABOVE GUIDANCE...AND ALSO THE LATEST RAP
MODEL TRENDS OF QUICKLY WARMING SFC WET BULB TEMPERATURES ABOVE
FREEZING ACROSS THE SRN HALF BY THE TIME THE HEAVIER PRECIPITATION
ARRIVES LATE AFTN/EVENING. THE LATEST NAM AND GFS ARE MUCH COLDER
WITH SFC WET BULBS AND THE SREF MEAN IS A COMPROMISE...WITH THE MAIN
WARMING OVER THE NE GA FOOTHILLS/PIEDMONT AND WRN SC UPSTATE. THE
ONE CERTAINTY IS THAT QPF SHOULD BE SUFFICIENT FOR SIGNIFICANT
WINTRY PRECIP IN ANY AREAS WHERE THE PROFILES SUPPORT WINTER TYPES.
WILL THUS SHARPEN UP THE GRADIENT OF SNOW AND ICE ACCUMS ACROSS THE
FORECAST AREA...WITH MOSTLY COLD RAIN NOW EXPECTED FROM TOCCOA TO
ANDERSON TO LAURENS TO CHESTER...BUT WITH A VERY SHARP TRANSITION TO
SIGNIFICANT ICING FROM THE GA MTNS TO GREENVILLE/SPARTANBURG TO ROCK
HILL/CHARLOTTE/MONROE. NRN BLUE RIDGE AREA SNOW TOTALS HAVE BEEN
INCREASED SLIGHTLY AS WELL...BUT AGAIN SOME SLEET WILL MIX IN AT
TIMES TO SLIGHTLY CURB TOTALS BELOW WHAT QPF INDICATES. WILL
CONTINUE TO FOLLOW 4 KM WRF AND HRRR CONSENSUS ON ARRIVAL TIMES
ACROSS THE REGION.
DRY SLOTTING IS EXPECTED AT MID LEVELS FROM THE SW OVERNIGHT...AND
THE HEAVIER PRECIP SHOULD CUT OFF FAIRLY RAPIDLY. HOWEVER...COLD AIR
WILL QUICKLY RETURN FROM THE NW TO PRODUCE A TRANSITION BACK OVER TO
SNOW FOR ANY NW FLOW PRECIPITATIO THROUGH DAYBREAK. NO CHANGES IN THE
WARNING/ADVISORY PRODUCTS HAVE BEEN MADE...BUT THE GRADIENT AMONG
ALL SNOW/ICE ACCUMS HAS BEEN SHARPENED.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...THE 00Z MODELS ARE IN VERY GOOD AGREEMENT ON
THE BACK EDGE OF THE PRECIP SHIELD PRETTY MUCH COMPLETELY EXITED OFF
TO THE EAST BY 12Z TUESDAY...EXCEPT FOR SOME LINGER NW FLOW CHCS FOR
TUESDAY MORNING. OTHERWISE...TUESDAY LOOKS LIKE A COLD DAY...WITH
PERSISTENT 850 MB CAA ALL DAY. TEMPS DO REBOUND FROM SUN-MON
READINGS...BUT STILL 10-15 DEG BELOW NORMAL (20S TO UPR 30S MTNS AND
MAINLY LWR-MID 40S PIEDMONT).
TUESDAY NIGHT THRU WEDNESDAY NIGHT...ANOTHER PIECE OF THE POLAR
VORTEX WILL DIG INTO THE GREAT LAKES...AND BRING TWO SHOTS OF
REINFORCING ARCTIC AIR. THE FIRST WILL BE WEDNESDAY MORNING...WITH
STRONG CAA AND SOME LLVL MOISTURE FOR NW FLOW SNOW SHWR ACTIVITY.
THE SECOND (STRONGER) FRONT WILL CROSS THE AREA WEDNESDAY NIGHT. THE
MAIN CONCERN WITH THE FIRST FRONT WILL BE SNOW ALONG THE TN BORDER.
GUIDANCE HAS TRENDED A LITTLE WETTER...BUT LIKE THE LAST FEW FRONTS
OF THIS NATURE...THE TIME INTERVAL IS RATHER SHORT...AND GENERALLY
SUB-ADV ACCUMS ARE EXPECTED. I DID BUMP UP POP FOR WEDNESDAY IN THE
NC MTNS. THE OP MODELS AGREE ON STEEP LLVL LAPSE RATES ACRS THE
PIEDMONT WITH AT LEAST A SLGT CHC OF A FEW SHWRS BREAKING
CONTAINMENT FROM THE TN LINE WED AFTN. I INTRODUCED A SLGT CHC OF
SNOW SHWRS ACRS THE NC PIEDMONT. NO ACCUMS EXPECTED...BUT AN ISOLD
DUSTING LOOKS POSSIBLE. TEMPS WEDNESDAY WILL BE 2-3 CATEGORIES
COLDER THAN TUESDAY. WITH THE SECOND FRONT WEDNESDAY NIGHT...THE
BIGGER CONCERN WILL BE WIND CHILLS. THE 850 MB TEMPS PLUMMET TO -17
TO -24C ACRS MOST OF THE CWFA. WITH STILL DECENT WINDS OF 30-40 KTS
AT 850 MB AND CAA...SHUD SEE GUSTY WINDS LINGERING OVERNIGHT IN THE
MTNS AND A LIGHT WIND ACRS THE PIEDMONT. THIS COUPLED WITH LIKELY
RECORD LOW TEMPS THURSDAY MORNING WILL RESULT IN SOLID WIND CHILL
ADV CRITERIA ACRS NEARLY THE ENTIRE CWFA...AND WIND CHILL WARNING
ACRS ALL THE NC MTNS ABOVE 3500 FT. WILL HIGHLIGHT DANGEROUS WIND
CHILLS IN THE HWO. FOR THE DAILY RECORD LOWS FOR THURSDAY SEE
CLIMATE SECTION BELOW.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 255 AM MONDAY...ONLY A FEW CHANGES WERE MADE THE PREVIOUS FCST
AS GUIDANCE CONTINUES TO SHOW UNCERTAINTY WITH THE EVOLUTION OF THE
SRN STREAM SFC BNDRY AND DEGREE/PLACEMENT OF SFC CYCLOGENESIS. THERE
SHOULD BE A GOOD AMOUNT OF GOM MOISTURE FLUX AFT THU BUT AGAIN...AN
AGREEABLE AREA OF LIKELY PRECIP REMAINS TO BE WORKED OUT.
WITH A VERY COLD START TO THE DAY THU AND A CA HIGH CENTER WORKING
ACROSS TN...MAX TEMPS WILL RECOVER ONLY NOMINALLY EVEN WITH VERY
GOOD INSOL. RECORD LOW MAXES ARE STILL FCST/D BY A FEW DEGREES. THU
NIGHT AND FRI WILL REMAIN QUITE COLD AS THE SFC HIGH SHIFTS EAST
ACROSS SRN VA AND ENABLES GOOD RAD COOLING AND A SLOWLY VEERING FLOW.
THUS...MINS AND MAXES WILL AGAIN APPROACH AND POSSIBLY BREAK RECORD
LEVELS. SEE THE CLIMATE SECTION OF THIS AFD FOR THE ACTUAL RECORD
VALUES. VERY COLD WIND CHILLS WILL DEVELOP THU NIGHT ACROSS THE
FCST AREA...WITH THE NC MTNS LIKELY REACHING WARNING/ADV CRITERIA
THROUGH DAYBREAK.
THE PATTERN REMAINS ACTIVE FRI THROUGH THE WEEKEND. HOWEVER...MORE
UNCERTAINTY ARISES...WITH THE OP MODELS CONTINUING TO SHOW DISPARATE
HANDLINGS WRT THE SRN BNDRY AND INTERACTIONS WITH ULVL S/W ENERGY.
THE LATEST TREND HAS BEEN FOR A SLOWER ADVANCEMENT EAST WITH
MEASURABLE PRECIP FRI AS A STUBBORN CA HIGH PERSISTS OVER THE
CAROLINAS. THE ECMWF HAS MORE RIDGING ALOFT AND THIS KEEPS IT/S SFC
BNDRY MORE NORTH AND WEST THAN THE GFS THROUGH THE PERIOD. SO...POPS
WERE ADJ DOWN A LITTLE ACCOUNT FOR HIGHER UNCERTAINTY MAINLY ACROSS
THE SRN ZONES. PRECIP SHOULD BE MAINLY DIURNAL RAIN/SNOW...WITH SOME
LOW SNOW ACCUMS POSSIBLE OUTSIDE THE MTNS FRI NIGHT AND AGAIN
NON/MTN -SNSH POSSIBLE SAT NIGHT OVER THE NRN ZONES. MAX TEMPS
SHOULD WARM 8-10 DEGREES BOTH SAT AND SUN...YET STILL A COUPLE
DEGREES BELOW NORMAL SUN AFTERNOON.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL CONTINUE THROUGH THIS AFTERNOON WITH
WINDS FROM THE ESE TO SE. BASED ON LATEST GUIDANCE AND FORECAST
SOUNDINGS...FZRA/SN/IP SHOULD DEVELOP AROUND 21Z...WITH FZRA
INCREASING THROUGH THE EVENING. PRECIP RATES SHOULD DROP OFF SHARPLY
BETWEEN 06Z TO 09Z. VSBY AND CIGS SHOULD DECREASE TO IFR THIS
EVENING AS THE PRECIP RATES INCREASE. TEMPERATURES DURING THE
PRECIPITATION SHOULD LINGER JUST BELOW FREEZING. IT APPEARS THAT BY
12Z THE TERMINAL WILL RECEIVE AROUND TWO TENTHS OF AN INCH OF SLEET
WITH BETWEEN TWO TO THREE TENTHS OF AN INCH OF FZRA. DEICING WILL
BECOME A BIG ISSUE EARLY TUESDAY. WINDS ARE FORECAST TO BECOME NORTH
BY 9Z.
ELSEWHERE...MODELS ARE IN GOOD AGREEMENT WITH THE PLACEMENT AND
TIMING OF THE MAJOR FEATURES OF THE NEAR TERM FORECAST. IT APPEARS
THAT PRECIP WILL BEGIN AT KAVL AROUND 17Z TO 18Z...THEN REACHING THE
WESTERN CAROLINA TERMINALS BETWEEN 21Z TO 22Z. KAVL WILL HAVE THE
COLDER THERMAL PROFILES...KEEPING A MIX OF SN/IP THROUGH THIS
AFTERNOON...THEN MIXING WITH FZRA THROUGH THE EVENING HOURS. VIS AND
CIGS WILL FALL TO MVFR BY 21Z...REACHING LIFR BY 4Z. EAST OF THE
MTNS...PRECIP WILL FAVOR FZRA...WITH PERIODS OF SN/IP AT KHKY...AND
RA AT KAND. ALL SITES WILL SEE IFR TO LIFR CONDITIONS BY THIS
EVENING. WINDS WILL VEER FROM ENE THIS MORNING TO SOUTHEAST BY THIS
AFTERNOON...KAVL FAVORING A SE DIRECTION. KAVL WINDS ARE FORECAST TO
BECOME NORTH BY 9Z.
OUTLOOK...CONDITIONS WILL IMPROVE TO VFR BY WEDNESDAY AND THEN
CONTINUE THURSDAY...BUT BECOMING VERY COLD.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-12Z
KCLT HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL MED 74% HIGH 100% HIGH 100% HIGH 100%
KHKY MED 77% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
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
&&
.CLIMATE...
RECORD MINIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 9 1958
CLT 8 1958
AVL 7 1958
RECORD LOW MAXIMUM TEMPERATURES FOR THURSDAY...FEBRUARY 19TH...
GSP 30 1900
CLT 34 1958
AVL 25 1958
RECORD MINIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 13 1903
CLT 13 1896
AVL 10 1979
RECORD LOW MAXIMUM TEMPERATURES FOR FRIDAY...FEBRUARY 20TH...
GSP 34 1947
CLT 32 1947
AVL 26 1979
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR GAZ010-017.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR GAZ018.
NC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR NCZ033-048>053-
058-059-062>065-501-503-505-507-509.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR NCZ035>037-056-
057-068>072-082-502-504-506-508-510.
SC...WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR SCZ001>003.
WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR SCZ005>009.
WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR SCZ004-010-
012>014.
&&
$$
SYNOPSIS...SBK
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...SBK
AVIATION...HG/NED
CLIMATE...
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
937 PM CST TUE FEB 17 2015
.UPDATE...LATEST HRRR CONTINUES TO BRING A BAND OF REFLECTIVITY
ACROSS MAINLY NORTHERN MIDDLE TENNESSEE AND THE PLATEAU
OVERNIGHT. BEST ESTIMATES FOR TIMING ARE CKV AROUND 08Z, BNA
AROUND 09Z, AND CSV AROUND 11Z. ENHANCES ECHOES WITHIN THE LARGER
BAND SUGGEST THE HRRR IS HONING IN ON SOME CONVECTIVE POTENTIAL,
SO BRIEF PERIODS OF HEAVIER SNOW ARE POSSIBLE, ESPECIALLY NORTH OF
I-40. HAVE ALREADY MADE SOME ADJUSTMENTS TO THE GRIDS BASED ON
EARLIER RUNS OF THE HRRR AND WILL SEND OUT AN UPDATE SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 542 PM CST TUE FEB 17 2015/
UPDATE...FOR 00Z AVIATION.
AVIATION...00Z TAF DISCUSSION.
SOME MVFR IS BEING EXPERIENCED AT KCSV...OTHERWISE VFR FOR SEVERAL
MORE HOURS. A CLIPPER WILL BRING IN MVFR TO IFR CIGS AND SNOW
AFTER 06Z TONIGHT FOR ALL OF OUR TERMINALS. SOME MVFR VIS
IS LIKELY AS WELL BY SUNRISE WITH THE SNOW. SNOW ACCUMULATIONS
ARE POSSIBLE AS WELL FOR ALL TERMINALS.
LIGHT SOUTHERLY TO SOUTHWESTERLY OVERNIGHT WINDS WILL KICK UP
WEDNESDAY MORNING AFTER 12Z. WINDS WILL SHIFT AND NW GUSTS OF
20-25 KTS WILL BE LIKELY BEHIND THE FRONT.
UNGER
PREV DISCUSSION... /ISSUED 520 PM CST TUE FEB 17 2015/
UPDATE...FOR ADDITIONAL INFORMATION.
DISCUSSION...
I WANTED TO ADD A COUPLE OF ADDITIONAL WORDS TO THE DISCUSSION
AFTER DRIVING IN THIS AFTERNOON. WHILE WE DID EXPERIENCE COPIOUS
SUNSHINE TODAY...MANY TREES AND POWER LINES ARE STILL COATED IN
ICE. MANY ARE STILL WITH ONE QUARTER OF AN INCH BUT MANY WITH EVEN
MORE. TEMPERATURES WILL FALL OFF RAPIDLY TONIGHT...MOST INTO THE
TEENS...AND PUT A HALT TO ANY MELTING THAT HAS STARTED. THE
DOWNSIDE...WINDS ARE EXPECTED TO INCREASE BEHIND TONIGHT`S
CLIPPER. GUSTS OF AT LEAST 20-25 MPH WILL LIKELY BEGIN AFTER 6 AM
WEDNESDAY MORNING...AND WHILE THAT WILL DROP WIND CHILLS INTO THE
SINGLE DIGITS...MORE CONCERNING IS THE INTERACTION THAT THE WIND
WILL HAVE WITH THE ICE THAT IS STILL COATING MANY TREES AND POWER
LINES ACROSS MIDDLE TN. I DON`T WANT TO DRAW ANY CONCLUSIONS AS TO
WHAT KIND OF AFFECT THIS WILL HAVE...BUT SOME POWER INTERRUPTIONS
COULD BE EXPERIENCED... ESPECIALLY IN THOSE AREAS THAT SAW THE
HIGHEST ICE ACCUMULATIONS ON MONDAY. PLEASE HEED POWER COMPANY
INSTRUCTIONS ABOUT NOT GOING ANYWHERE NEAR DOWNED POWER LINES IF
YOU DO ENCOUNTER ANY TOMORROW MORNING.
THE REST OF THE FORECAST IS INTACT FOR THE REMAINDER OF THE
EVENING.
UNGER
PREV DISCUSSION... /ISSUED 354 PM CST TUE FEB 17 2015/
DISCUSSION...AFTERNOON TEMPERATURES WERE IN THE 20S. EVEN WITH
THOSE FREEZING TEMPS...SUNSHINE WAS HELPING MELT A LOT OF THE ICE
ON AREA ROADS AND OTHER SURFACES. UNFORTUNATELY...ANY LEFTOVER
MOISTURE WILL QUICKLY REFREEZE TONIGHT. IN ADDITION TO THAT TRAVEL
ISSUE...WE ARE EXPECTING SOME ACCUMULATING SNOW LATE TONIGHT INTO
WEDNESDAY MORNING AS A CLIPPER SYSTEM COMES DOWN INTO THE AREA. THE
LEADING PIECE OF ENERGY WITH THIS SYSTEM WAS OVER NE/KE..MOVING
INTO MO THIS AFTERNOON. THERE WILL BRING A SLIGHT CHANCE FOR THAT
SNOW REACHING OUR NW COUNTIES AFTER 10 PM...BUT MOST OF THE ACTION
WILL OCCUR BETWEEN 3 AM AND 10 AM. THIS EVENT WILL BE RELATIVELY
LIGHT IN TERMS OF LIQUID EQUIVALENT PRECIPITATION...BUT THIS EVENT
WILL BE ALL SNOW. ALSO...THE COLD ATMOSPHERE WILL GIVE US A SNOW TO
LIQUID RATIO AROUND 16 TO 1. OUR FORECAST IS A MODEL BLEND...AND
THE MODELS ARE IN PRETTY GOOD AGREEMENT. INTERESTINGLY...THIS
CLIPPER SYSTEM WILL BRING UNSTABLE CONDITIONS. FORECAST SOUNDINGS
SHOW UP TO 150 J/KG OF CAPE AND TOTAL TOTALS OF 55+ AROUND 12Z. WE
ALREADY SEE SOME LIGHTNING SHOWING UP OVER KS. THIS INSTABILITY
COULD BRING SOME LOCALIZED ENHANCED BURSTS OF SNOW...ESPECIALLY
FOR THE NORTH HALF OF THE AREA. WE EXPECT THE MAIN BATCH OF SNOW
TO BE GONE BY NOON...BUT STRONG COLD ADVECTION AND INSTABILITY
WILL KEEP SOME SCATTERED SNOW SHOWERS GOING INTO THE AFTERNOON.
SOME LOCALIZED ACCUMS CANNOT BE RULED OUT WITH THESE LINGERING
SNOW SHOWERS...BUT CONFIDENCE AND COVERAGE IS TOO LIMITED TO KEEP
THE ADVISORY GOING BEYOND NOON.
IN ADDITION TO SNOW...THIS CLIPPER SYSTEM WILL BRING MORE COLD AIR
AND GUSTY WINDS. TEMPS WILL BE ONLY IN THE 20S TOMORROW...AND
BRISK WINDS WILL DROP WIND CHILLS INTO THE SINGLE DIGITS. FOR
TOMORROW NIGHT...FRIGID CONDITIONS ARE EXPECTED WITH TEMPS
DROPPING BELOW ZERO OVER MUCH OF THE AREA. WE ARE NOT HIGHLY
CONFIDENT ON THE EXACT LOWS FOR WEDNESDAY NIGHT...SINCE THERE ARE
CLOUD AND WIND ISSUES TO DEAL WITH. BUT IT SEEMS THE MODELS ARE
NOT PICKING UP ON THE INFLUENCE OF GOOD SNOW COVER JUST TO OUR
NORTH...AND POSSIBLE LIGHT SNOW COVER THAT WILL SPREAD OVER MID
TN. WITH A WIND FETCH ACROSS A WIDESPREAD SNOW PACK...RECORD
SETTING LOW TEMPERATURES ARE A GOOD BET AROUND DAYBREAK THURSDAY.
OUR CURRENT BNA LOW TEMP RECORD IS 5 DEGREES FOR FEB 19. THIS AIR
MASS IS SO COLD THAT HIGHS MAY ONLY REACH THE TEENS ON THURSDAY
EVEN WITH SOME SUNSHINE. THIS WOULD ALSO BE RECORD SHATTERING WITH
OUR RECORD LOWEST MAX TEMP FOR THE DATE OF 26.
THE COLD AIR WILL REMAIN THURSDAY NIGHT WITH LOWS VARYING FROM
SINGLE DIGITS BELOW ZERO IN OUR NORTHEAST TO AROUND 15 ABOVE IN
THE SOUTHWEST.
BY FRIDAY...THE ARCTIC HIGH PRESSURE WILL BE MOVING OFF TO THE
EAST...AND RETURN FLOW WILL DEVELOP AHEAD OF THE NEXT MAJOR LOW
PRESSURE SYSTEM. THIS WILL SET US UP FOR A VERY MESSY SITUATION
GOING INTO THE WEEKEND. WIDESPREAD WARM ADVECTION PRECIPITATION
WILL INCREASE OVER THE REGION FRIDAY. FORECAST SOUNDINGS SHOW
PRECIP STARTING AS LIGHT SNOW FRIDAY...WITH SOME ACCUMULATIONS
POSSIBLE. THEN...FRIDAY NIGHT THROUGH SATURDAY MORNING...WARMER
AIR WILL BRING A TRANSITION THROUGH SLEET AND FREEZING RAIN...AND
EVENTUALLY TO ALL LIQUID RAIN BY MIDDAY SATURDAY. ICE BUILDUP MAY
OCCUR FRIDAY NIGHT...ESPECIALLY IN OUR SOUTHERN COUNTIES...AND TRAVEL
MAY BECOME QUITE HAZARDOUS UNTIL TEMPS WARM ABOVE FREEZING ON
SATURDAY. FOLLOWING THE CHANGE TO RAIN...THE RAIN COULD BE
MODERATE TO HEAVY...WITH POSSIBLY AN INCH OF RAIN. THE RAIN WILL
TAPER OFF SUNDAY INTO SUNDAY NIGHT...WITH A LITTLE SNOW POSSIBLE
ON THE BACK EDGE. COLD AND DRY TO START THE NEW WORK WEEK.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR TNZ005>011-
023>034-056>066-075-077>080-093>095.
&&
$$
ROSE
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
343 PM CST MON FEB 16 2015
.DISCUSSION...
LIGHT RAIN CONTINUES ACROSS OUR SOUTHEAST COUNTIES THIS AFTERNOON
BUT SHOULD MOVE OUT OF THE REGION BY SUNSET. TEMPERATURES IN THIS
AREA HAVE STAYED ABOVE FREEZING AND EXPECT ALL RAIN TO REMAIN IN
LIQUID FORM THROUGH THE REMAINDER OF THE AFTERNOON HOURS. A
RELATIVELY DRY EVENING AND NIGHT IS EXPECTED BUT THERE STILL
REMAINS A LOW CHANCE FOR LIGHT SNOW OR SNOW FLURRIES OVER THE
REGION LATE TONIGHT AND TUESDAY MORNING.
BROAD UPPER LEVEL TROUGHING CONTINUES ACROSS THE REGION THIS
AFTERNOON. A DISTURBANCE...CURRENTLY MOVING ACROSS UTAH...WILL
CONTINUE SOUTHEAST INTO WEST TEXAS LATE TONIGHT AND THEN MOVE
ACROSS NORTH TEXAS DURING THE DAY ON TUESDAY. THIS DISTURBANCE IS
EXPECTED TO GENERATE ENOUGH MID LEVEL LIFT TO PRODUCE SNOW ACROSS
WEST TEXAS TONIGHT WITH POSSIBLY A BAND OF LIGHT SNOW OCCURRING
ACROSS THE WESTERN COUNTIES OF NORTH TEXAS. FORECAST SOUNDINGS
CONTINUE TO INDICATE THE LOWER LEVELS OF THE ATMOSPHERE WILL
REMAIN DRY MAKING IT DIFFICULT FOR MUCH OF THE SNOW TO REACH THE
GROUND. THE FURTHER EAST YOU GO...THE DEEPER THE DRY LAYER AT THE
SURFACE. WILL KEEP A SLIGHT CHANCE FOR SNOW ALONG AND WEST OF A
LINE FROM BRIDGEPORT TO WEATHERFORD TO KILLEEN OVERNIGHT TONIGHT
AND TUESDAY MORNING. DO NOT THINK ALL OF THIS AREA WILL SEE
SNOW...BUT AM NOT SURE EXACTLY WHERE THE BAND OF SNOW WILL OCCUR.
MOST OF THE HI-RES GUIDANCE SUGGESTS IT MAY OCCUR NEAR OR NORTH OF
I-20. A TRACE OF SNOW ACCUMULATION MAY OCCUR ON GRASS UNDERNEATH
THE SNOW BAND BUT NO IMPACTS ARE EXPECTED FROM ANY SNOW THAT DOES
FALL. EAST OF THIS AREA...WILL KEEP A MENTION FOR FLURRIES WITH A
LESS THAN 20 POP.
DURING THE AFTERNOON AND EARLY EVENING HOURS OF TUESDAY...BOTH THE
TEXAS TECH WRF AND NAM SUGGEST SOME LIGHT RAIN OR DRIZZLE MAY
OCCUR IN OUR NORTHWEST AND/OR NORTH COUNTIES AS THE DISTURBANCE
EXITS THE REGION...BUT THINK WITH THE NEAR-SURFACE DRY LAYER IT
WILL STILL BE DIFFICULT FOR ANY PRECIP TO REACH THE GROUND. IF
ANYTHING DOES REACH THE GROUND...SOUNDINGS INDICATE IT WOULD
REMAIN AS LIQUID RAIN OR DRIZZLE. FOR NOW...WILL KEEP A 10 POP BUT
NOT MENTION ANY RAIN OR DRIZZLE IN THE WORDED FORECAST.
FOR THE REMAINDER OF THE WORK WEEK...WE WILL REMAIN UNDER
NORTHWEST FLOW ALOFT WITH A LARGE UPPER LEVEL TROUGH SLOWLY MOVING
EAST OVER THE EASTERN HALF OF THE CONUS. A WEAK FRONT WILL MOVE
INTO AT LEAST THE EASTERN HALF OF THE CWA ON WEDNESDAY BUT IT WILL
HARDLY BE NOTICED EXCEPT FOR A WIND SHIFT TO THE NORTH.
TEMPERATURES WILL STEADILY WARM THROUGH FRIDAY. RAIN CHANCES
RETURN TO THE FORECAST ON THURSDAY NIGHT AND FRIDAY AS WARM AIR
ADVECTION ALLOWS FOR SOME LIGHT RAIN OVER MAINLY THE EASTERN HALF
OF THE CWA.
BEGINNING ON FRIDAY...A POSITIVELY-TILTED AND NEARLY ZONAL TROUGH
WILL BEGIN TO DEVELOP ALONG THE WEST COAST. AS THIS DEVELOPS...IT
WILL SEND A STRONGER COLD FRONT INTO THE REGION THIS WEEKEND. THE
GEM AND ECMWF ARE IN FAIRLY GOOD AGREEMENT THAT THE FRONT WILL
ARRIVE SATURDAY AND SATURDAY NIGHT WHILE THE GFS STALLS THE FRONT
JUST NORTH OF THE AREA. HOWEVER...IN PREVIOUS MODEL RUNS THE GFS
BROUGHT THE FRONT THROUGH THE AREA THIS WEEKEND. THIS FORECAST
WILL LEAN MORE TOWARDS THE CONSENSUS OF THE ECMWF AND GEM WITH THE
FRONT ARRIVING ON SATURDAY. THERE WILL BE A CHANCE FOR RAIN AND
ISOLATED THUNDERSTORMS WITH THE FRONT ON SATURDAY AND SATURDAY
NIGHT. DEPENDING ON WHAT THE UPPER LEVEL PATTERN EVENTUALLY
EVOLVES INTO...THERE COULD BE LINGERING PRECIP CHANCES THROUGH
THE REMAINDER OF THE WEEKEND AND INTO EARLY NEXT WEEK. THE ECMWF
SOUNDINGS SUGGEST THAT THE ATMOSPHERIC PROFILES WILL BE COLD ENOUGH
FOR POSSIBLY SOME SNOW. WILL MENTION A RAIN/SNOW MIX ACROSS THE
NORTHERN HALF OF THE REGION SUNDAY NIGHT AND MONDAY BUT THIS
POTENTIAL EVENT IS STILL 6-8 DAYS OUT AND THERE ARE LIKELY TO BE
CHANGES TO THE FORECAST BEFORE THEN.
82/JLD
&&
.AVIATION...
/ISSUED 1252 PM CST MON FEB 16 2015/
FOR THE 18Z TAFS...MVFR CIGS ARE EXPECTED TO REMAIN IN PLACE
THROUGH THIS EVENING. ON AND OFF LIGHT RAINFALL WILL CONTINUE
AROUND CENTRAL TEXAS THROUGH THE MID-AFTERNOON HOURS...WITH
TEMPERATURES HOVERING AROUND OR JUST ABOVE FREEZING FOR WACO.
A SUFFICIENT AMOUNT OF LOW-LEVEL DRY AIR SEEMS TO HAVE ADVECTED
ACROSS NORTH TEXAS TO PREVENT ANY PRECIPITATION FROM REDEVELOPING
OVER DFW AREA AIRPORTS. A WEAK UPPER LEVEL DISTURBANCE OVER FAR
WEST TEXAS WILL MOVE NORTHEAST THROUGH THIS AFTERNOON PROVIDING
PERSISTENT LIFT OVER CENTRAL TEXAS FOR ON AND OFF LIGHT RAIN. FOR
THE WACO TAF...THE CURRENT TEMPERATURE WAS 33 DEGREES...AND THE
TEMPERATURE IS UNLIKELY TO CHANGE SIGNIFICANTLY OVER THE NEXT FEW
HOURS. AS A RESULT...HAVE SIMPLY LEFT A MENTION OF LIGHT RAIN IN
THE FORECAST WITH MVFR CIGS THROUGH THIS AFTERNOON FOR KACT.
LEFT MVFR CIGS IN PLACE WITH NO MENTION OF PRECIPITATION ACROSS
ALL OF THE DFW AREA TAF SITES THROUGH THIS EVENING. LINGERED MVFR
CIGS IN PLACE LONGER THAN THE PREVIOUS FORECAST DUE TO THE LATEST
FORECAST SOUNDINGS FROM THE HRRR WHICH SEEMS TO BE HANDLING
CURRENT CONDITIONS FAIRLY ACCURATELY. DRY AIR ADVECTION AND MID-
LEVEL SUBSIDENCE ARE EXPECTED ACROSS THE ENTIRE REGION THIS
EVENING...WHICH SHOULD ALLOW LOW CLOUDS TO SCATTER OUT JUST
LEAVING VFR CLOUDS IN PLACE.
A SECOND UPPER LEVEL DISTURBANCE WILL SPREAD LIFT OVER THE REGION
EARLY TOMORROW MORNING. THE LIFT IS FAIRLY STRONG WITH THIS
DISTURBANCE...HOWEVER THE LOW-LEVEL ATMOSPHERE IS EXPECTED TO
REMAIN QUITE DRY. AS A RESULT...THINK THAT WE WILL HAVE SNOW
GENERATED FROM CLOUDS BASED AT NEAR THE 700 MB LEVEL...OR 9000 FT
AGL. BELOW THE 700 MB LEVEL...DRY AIR IS EXPECTED TO PREVENT MOST
OF THIS SNOW FROM REACHING THE GROUND. AS A RESULT...LEFT SNOW OUT
OF THE FORECAST FOR TOMORROW MORNING FOR ALL AREA TAF SITES. WILL
CONTINUE TO WATCH LOW-LEVEL MOISTURE PROFILES CLOSELY
OVERNIGHT...HOWEVER ALL MODEL GUIDANCE INDICATES THIS DRY AIR WILL
BE IN PLACE...SO DO NOT SEE MUCH MORE THAN FLURRIES MAKING IT
THROUGH 8-9000 FEET OF DRY AIR BELOW THE SNOW GENERATING CLOUDS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 27 50 32 57 33 / 10 10 5 0 0
WACO, TX 27 49 31 61 34 / 10 10 5 0 0
PARIS, TX 22 46 27 50 26 / 10 10 10 0 0
DENTON, TX 26 51 30 56 31 / 10 10 10 0 0
MCKINNEY, TX 26 49 29 53 29 / 10 10 10 0 0
DALLAS, TX 29 50 34 57 34 / 10 10 5 0 0
TERRELL, TX 28 48 32 56 30 / 10 10 5 0 0
CORSICANA, TX 28 48 32 58 33 / 10 10 5 0 0
TEMPLE, TX 29 50 32 63 35 / 10 10 5 0 0
MINERAL WELLS, TX 29 51 31 59 32 / 20 20 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/82
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
316 PM CST MON FEB 16 2015
.SHORT TERM /NOW THROUGH TUESDAY NIGHT/...A STRONG COLD FRONT
EXTENDING CURRENTLY FROM NEAR RIO GRANDE CITY TO NEAR BAFFIN BAY
WITH A PRE FRONTAL TROUGH AHEAD OF THE FRONT...ACROSS THE UPPER
PORTIONS OF THE RIO GRANDE VALLEY. WEST TO SOUTHWEST WINDS BETWEEN
2 TO 4K FEET MIXING DOWN TO THE SURFACE ALONG WITH FULL SUNSHINE HAS
ALLOWED TEMPERATURES TO SPIKE INTO THE LOW TO MID 80S ACROSS THE
VALLEY. BASED ON THE LATEST NAM/RAP AND HRRR DATA...THE STRONG FRONT
IS EXPECTED TO MOVE THROUGH MCALLEN AND HARLINGEN BETWEEN 4 AND 5
PM...BROWNSVILLE BETWEEN 5 AND 6 PM AND OFF THE LOWER TEXAS COAST
AROUND 7 PM. A DRASTIC CHANGE TO TEMPERATURES...BREEZY NORTH
WINDS...INCREASING LOW CLOUDINESS AND A POSSIBLE LIGHT SHOWER WILL
ACCOMPANY THE SHARP FROPA. TEMPERATURES WILL CONTINUE TO DROP
THROUGH THE EVENING WITH OVERNIGHT LOW TEMPERATURES IN THE 40S UNDER
MOSTLY CLOUDY SKIES. A MID TO UPPER LEVEL DISTURBANCE WILL MOVE
OVERHEAD TONIGHT. THIS FEATURE WILL SUPPORT ISOLATED TO SCATTERED
SHOWERS ACROSS THE REGION TONIGHT AND MAY LINGER ALONG THE COAST
INTO THE GULF WATERS TUESDAY MORNING.
SURFACE HIGH PRESSURE WILL BUILD ACROSS DEEP SOUTH TEXAS ON TUESDAY.
SKIES WILL GRADUALLY CLEAR BY TUESDAY AFTERNOON WITH TEMPERATURES
REMAINING WELL BELOW NORMAL. HIGH TEMPERATURES ON TUESDAY WILL BE IN
THE MID TO UPPER 50S WITH A FEW 60S POSSIBLE ACROSS THE WESTERN AREA
WITH MODERATE NORTH TO NORTHEAST WINDS. SURFACE HIGH PRESSURE
SETTLES ACROSS THE AREA TUESDAY NIGHT. CLEAR SKIES...DRY AIR AND
LIGHT WINDS WILL ALLOW FOR GOOD RADIATIONAL COOLING TUESDAY NIGHT.
OVERNIGHT LOW TEMPERATURES TUESDAY NIGHT EXPECTED TO FALL INTO THE
UPPER 30S ACROSS THE NORTHERN RANCHLANDS...LOWER 40S ACROSS THE RIO
GRANDE VALLEY AND THE MID 40S ALONG THE BEACHES.
.LONG TERM /WEDNESDAY THROUGH MONDAY/...500 MB RIDGING WILL
BUILD OVER DEEP SOUTH TX STARTING WEDNESDAY CONTINUING INTO FRIDAY
WHICH WILL ALLOW THE 1000-500 MB THICKNESSES TO INCREASE WITH A
PERSISTENT S-SE SURFACE FLOW BRINGING IN STEADY WAA AT THE LOW
LEVELS. THIS WILL ALLOW TEMPS TO STEADILY INCREASE THROUGH THE END
OF THIS WEEK. AS THE WEEKEND APPROACHES THE 500 MB RIDGE WILL BE
ERODED STEADILY AS A SERIES OF STRONG SHORT WAVES CARVE OUT A
BROAD 500 MB TROUGH OVER THE NORTHERN HALF OF THE LOWER 48 STATES.
AS THIS 500 MB TROFFING DEEPENS A COLD FRONT WILL BE PUSHED
TOWARDS DEEP SOUTH TX ON SUN.
THE ECMWF AND GFS ARE IN GOOD AGREEMENT IN THE OVERALL PLACEMENT
OF THE 500 MB FEATURES THROUGH FRI. THE MODELS THEN START TO
DIVERGE STEADILY FROM SAT THROUGH MON WITH THE ECMWF DIGGING A
DEEPER 500 MB TROUGH AXIS OVER THE LOWER 48 STATES VERSUS THE GFS.
THE GFS KEEPS THE 500 MB TROUGH AXIS MORE ELONGATED FROM THE WEST
COAST UP THROUGH THE GREAT LAKES WHICH KEEPS THE COLD FRONT FROM
PUSHING THROUGH THE RGV.
MOISTURE ADVECTION AHEAD OF THIS NEXT POTENTIAL FROPA IS NOT THE
GREATEST IN THE WORLD SO WILL HOLD THE POPS AROUND 20 % LATE IN
THE FORECAST PERIOD UNTIL THE MODELS RESOLVE THEMSELVES A BIT
BETTER.
WILL LEAN MORE TOWARDS THE ECMWF SOLUTION THROUGH DAY 7 FOR TEMPS.
OVERALL CONFIDENCE IN THE FORECAST IS PRETTY GOOD THROUGH FRI THEN
STARTS TO DROP FOR THE SAT THROUGH MON PERIOD DUE TO THE ECMWF AND
GFS DIVERGENCE LATE IN THE PERIOD.
&&
.MARINE...NOW THROUGH TUESDAY NIGHT...LIGHT SOUTH TO SOUTHWEST WINDS
WILL CONTINUE ALONG THE LOWER TEXAS COASTAL FOR THE NEXT FEW HOURS.
A STRONG COLD FRONT WILL MOVE FROM NORTH TO SOUTH ACROSS THE MARINE
AREA. WINDS WILL QUICKLY SHIFT TO THE NORTH TO NORTHWEST WITH GUSTY
WINDS. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE LOWER
TEXAS COASTAL WINDS DUE TO VERY STRONG WINDS WITH ROUGH SEAS ON THE
GULF. MARINE CONDITIONS GRADUALLY IMPROVE TUESDAY EVENING INTO
WEDNESDAY AS HIGH PRESSURE SETTLES ACROSS THE AREA.
WEDNESDAY THROUGH SATURDAY...A MODERATE TO STRONG S-SE WINDS WILL
PREVAIL IN THE LONGER RANGE MARINE FORECAST PERIOD AS BROAD
SURFACE RIDGING REMAINS IN PLACE OVER THE GULF OF MEX. THE PGF
TIGHTENS UP ENOUGH FROM LATE THURS THROUGH SATURDAY TO POSSIBLY
RESULT IN SOME SCA FOR THE GULF WATERS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 48 56 45 66 / 30 20 0 0
BROWNSVILLE 47 57 44 67 / 30 20 0 0
HARLINGEN 46 57 42 67 / 30 20 0 0
MCALLEN 47 60 42 68 / 20 10 0 0
RIO GRANDE CITY 47 60 41 69 / 20 10 0 0
SOUTH PADRE ISLAND 51 56 52 64 / 40 30 0 0
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 3 AM CST TUESDAY FOR GMZ130-
132-135.
SMALL CRAFT ADVISORY UNTIL 6 PM CST TUESDAY FOR GMZ150-155-170-
175.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...63
LONG TERM...60
GRAPHICAST/UPPER AIR...65
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1252 PM CST MON FEB 16 2015
.AVIATION...
FOR THE 18Z TAFS...MVFR CIGS ARE EXPECTED TO REMAIN IN PLACE
THROUGH THIS EVENING. ON AND OFF LIGHT RAINFALL WILL CONTINUE
AROUND CENTRAL TEXAS THROUGH THE MID-AFTERNOON HOURS...WITH
TEMPERATURES HOVERING AROUND OR JUST ABOVE FREEZING FOR WACO.
A SUFFICIENT AMOUNT OF LOW-LEVEL DRY AIR SEEMS TO HAVE ADVECTED
ACROSS NORTH TEXAS TO PREVENT ANY PRECIPITATION FROM REDEVELOPING
OVER DFW AREA AIRPORTS. A WEAK UPPER LEVEL DISTURBANCE OVER FAR
WEST TEXAS WILL MOVE NORTHEAST THROUGH THIS AFTERNOON PROVIDING
PERSISTENT LIFT OVER CENTRAL TEXAS FOR ON AND OFF LIGHT RAIN. FOR
THE WACO TAF...THE CURRENT TEMPERATURE WAS 33 DEGREES...AND THE
TEMPERATURE IS UNLIKELY TO CHANGE SIGNIFICANTLY OVER THE NEXT FEW
HOURS. AS A RESULT...HAVE SIMPLY LEFT A MENTION OF LIGHT RAIN IN
THE FORECAST WITH MVFR CIGS THROUGH THIS AFTERNOON FOR KACT.
LEFT MVFR CIGS IN PLACE WITH NO MENTION OF PRECIPITATION ACROSS
ALL OF THE DFW AREA TAF SITES THROUGH THIS EVENING. LINGERED MVFR
CIGS IN PLACE LONGER THAN THE PREVIOUS FORECAST DUE TO THE LATEST
FORECAST SOUNDINGS FROM THE HRRR WHICH SEEMS TO BE HANDLING
CURRENT CONDITIONS FAIRLY ACCURATELY. DRY AIR ADVECTION AND MID-
LEVEL SUBSIDENCE ARE EXPECTED ACROSS THE ENTIRE REGION THIS
EVENING...WHICH SHOULD ALLOW LOW CLOUDS TO SCATTER OUT JUST
LEAVING VFR CLOUDS IN PLACE.
A SECOND UPPER LEVEL DISTURBANCE WILL SPREAD LIFT OVER THE REGION
EARLY TOMORROW MORNING. THE LIFT IS FAIRLY STRONG WITH THIS
DISTURBANCE...HOWEVER THE LOW-LEVEL ATMOSPHERE IS EXPECTED TO
REMAIN QUITE DRY. AS A RESULT...THINK THAT WE WILL HAVE SNOW
GENERATED FROM CLOUDS BASED AT NEAR THE 700 MB LEVEL...OR 9000 FT
AGL. BELOW THE 700 MB LEVEL...DRY AIR IS EXPECTED TO PREVENT MOST
OF THIS SNOW FROM REACHING THE GROUND. AS A RESULT...LEFT SNOW OUT
OF THE FORECAST FOR TOMORROW MORNING FOR ALL AREA TAF SITES. WILL
CONTINUE TO WATCH LOW-LEVEL MOISTURE PROFILES CLOSELY
OVERNIGHT...HOWEVER ALL MODEL GUIDANCE INDICATES THIS DRY AIR WILL
BE IN PLACE...SO DO NOT SEE MUCH MORE THAN FLURRIES MAKING IT
THROUGH 8-9000 FEET OF DRY AIR BELOW THE SNOW GENERATING CLOUDS.
CAVANAUGH
&&
.UPDATE...
THE COLD FRONT HAS PUSHED WELL SOUTH OF THE REGION BUT A MIXTURE
OF LIGHT RAIN AND LIGHT FREEZING RAIN/DRIZZLE...OCCASIONALLY WITH
A FEW SLEET PELLETS...CONTINUES SOUTH OF A LINE FROM CISCO TO
DALLAS TO PARIS. TEMPERATURES SOUTH OF INTERSTATE 20 AND WEST OF
INTERSTATE 35 ARE WHERE THE FREEZING RAIN/DRIZZLE IS OCCURRING. A
VERY THIN GLAZE OF ICE MAY FORM ON METAL SURFACES AND POSSIBLY
TREE LEAVES...BUT ACCUMULATIONS OF ICE ON ROADWAYS ARE NOT
EXPECTED AND THUS WE DO NOT EXPECT ANY IMPACTS TO TRAVEL. THE
RAIN/DRIZZLE WILL CONTINUE THROUGH THE AFTERNOON HOURS...ENDING
FROM WEST TO EAST BY THIS EVENING. NEW MODEL DATA THIS MORNING
SUGGESTS A NEW BAND OF PRECIPITATION WILL FORM SOUTH OF INTERSTATE
20 AROUND MIDDAY DUE TO FORCING ALONG THE 850 MB FRONT AS A
SHEARED SHORTWAVE...CURRENTLY OVER WEST TEXAS...MOVES ACROSS NORTH
TEXAS. THIS NEXT WAVE OF PRECIPITATION MAY ALREADY BE TAKING SHAPE
FROM HAMILTON WEST TOWARDS OZONA. THROUGH AT LEAST THE EARLY
AFTERNOON HOURS...FREEZING RAIN/DRIZZLE WILL STILL BE POSSIBLE
WITH THIS ADDITIONAL PRECIPITATION UNTIL TEMPERATURES WARM NEAR
AND ABOVE FREEZING. HAVE KEPT HIGH POPS ACROSS THE SOUTHERN HALF
OF THE CWA FOR THIS REASON EVEN THOUGH THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD AND ANY ADDITIONAL ACCUMULATIONS LESS
THAN 0.02 INCHES OF LIQUID/MELTED PRECIPITATION.
OTHERWISE...EXPECT CLOUD COVER TO THIN AND THEN EVENTUALLY BREAK
UP ACROSS OUR WESTERN AND NORTHWESTERN COUNTIES THIS AFTERNOON
WHILE THE REST OF THE REGION REMAINS MOSTLY CLOUDY. HAVE LOWERED
TEMPERATURES THIS AFTERNOON A FEW DEGREES IN MOST PLACES BASED ON
CURRENT TEMPS AND EXPECTED CLOUD TRENDS FOR THE REMAINDER OF THE
DAY.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 30 48 34 55 34 / 10 10 5 0 0
WACO, TX 30 48 32 60 35 / 10 10 5 0 0
PARIS, TX 26 46 29 48 27 / 10 10 5 0 0
DENTON, TX 29 48 30 54 30 / 10 10 5 0 0
MCKINNEY, TX 28 48 30 52 30 / 10 10 5 0 0
DALLAS, TX 31 48 35 55 34 / 10 10 5 0 0
TERRELL, TX 29 47 31 54 31 / 10 10 5 0 0
CORSICANA, TX 29 47 33 58 33 / 10 10 5 0 0
TEMPLE, TX 31 48 32 61 35 / 10 10 5 0 0
MINERAL WELLS, TX 29 49 31 58 33 / 20 20 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1116 AM CST MON FEB 16 2015
.UPDATE...
THE COLD FRONT HAS PUSHED WELL SOUTH OF THE REGION BUT A MIXTURE
OF LIGHT RAIN AND LIGHT FREEZING RAIN/DRIZZLE...OCCASIONALLY WITH
A FEW SLEET PELLETS...CONTINUES SOUTH OF A LINE FROM CISCO TO
DALLAS TO PARIS. TEMPERATURES SOUTH OF INTERSTATE 20 AND WEST OF
INTERSTATE 35 ARE WHERE THE FREEZING RAIN/DRIZZLE IS OCCURRING. A
VERY THIN GLAZE OF ICE MAY FORM ON METAL SURFACES AND POSSIBLY
TREE LEAVES...BUT ACCUMULATIONS OF ICE ON ROADWAYS ARE NOT
EXPECTED AND THUS WE DO NOT EXPECT ANY IMPACTS TO TRAVEL. THE
RAIN/DRIZZLE WILL CONTINUE THROUGH THE AFTERNOON HOURS...ENDING
FROM WEST TO EAST BY THIS EVENING. NEW MODEL DATA THIS MORNING
SUGGESTS A NEW BAND OF PRECIPITATION WILL FORM SOUTH OF INTERSTATE
20 AROUND MIDDAY DUE TO FORCING ALONG THE 850 MB FRONT AS A
SHEARED SHORTWAVE...CURRENTLY OVER WEST TEXAS...MOVES ACROSS NORTH
TEXAS. THIS NEXT WAVE OF PRECIPITATION MAY ALREADY BE TAKING SHAPE
FROM HAMILTON WEST TOWARDS OZONA. THROUGH AT LEAST THE EARLY
AFTERNOON HOURS...FREEZING RAIN/DRIZZLE WILL STILL BE POSSIBLE
WITH THIS ADDITIONAL PRECIPITATION UNTIL TEMPERATURES WARM NEAR
AND ABOVE FREEZING. HAVE KEPT HIGH POPS ACROSS THE SOUTHERN HALF
OF THE CWA FOR THIS REASON EVEN THOUGH THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD AND ANY ADDITIONAL ACCUMULATIONS LESS
THAN 0.02 INCHES OF LIQUID/MELTED PRECIPITATION.
OTHERWISE...EXPECT CLOUD COVER TO THIN AND THEN EVENTUALLY BREAK
UP ACROSS OUR WESTERN AND NORTHWESTERN COUNTIES THIS AFTERNOON
WHILE THE REST OF THE REGION REMAINS MOSTLY CLOUDY. HAVE LOWERED
TEMPERATURES THIS AFTERNOON A FEW DEGREES IN MOST PLACES BASED ON
CURRENT TEMPS AND EXPECTED CLOUD TRENDS FOR THE REMAINDER OF THE
DAY.
82/JLD
&&
.AVIATION...
/ISSUED 932 AM CST MON FEB 16 2015/
THE DFW AREA TAFS REMAIN UNCHANGED FROM THEIR 12Z ISSUANCE.
UPDATED THE WACO (KACT) TAF TO INCLUDE A TEMPO GROUP FOR FREEZING
RAIN FROM 16 TO 17Z. THE 1530Z TEMPERATURE AT WACO WAS 34 DEGREES
WITH ONGOING LIGHT RAIN OVER MUCH OF MCLENNAN COUNTY. TEMPERATURES
ARE EXPECTED TO FALL TO 30 TO 32 DEGREES BEFORE DRIER AIR MOVES IN
AND PRECIPITATION DISSIPATES LATER THIS MORNING.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
BAND OF LIGHT TO MODERATE RAIN HAS PUSHED EAST OF TAF SITES AND
EXPECT JUST SOME LIGHT DRIZZLE TO BE THE PRIMARY PRECIPITATE THIS
MORNING. WHILE TEMPERATURES AT AFW/FTW/DFW ARE NOW 33...ANY
DRIZZLE THAT DOES FALL WOULD HAVE THE POTENTIAL TO FREEZE ON
CONTACT TO AIRPLANE SURFACES. THAT IS BECAUSE DRIZZLE DROPLETS
WOULD LIKELY BE SUPER-COOLED...SO EVEN IF AIR TEMPERATURE STAYS
AT 33...LIGHT ICING MAY BE AN ISSUE THIS MORNING THAT REQUIRES
SOME DEICING OPERATIONS. SINCE TEMPERATURES ARE EXPECTED TO REMAIN
VERY NEAR FREEZING...AND DRIZZLE WILL BE VERY LIGHT...WE DO NOT
EXPECT THE IMPACTS WITH FREEZING DRIZZLE TO BE ON THE ORDER OF
WHAT OCCURRED AT DFW A WEEK AND A HALF AGO. THE THREAT FOR DRIZZLE
AND/OR FREEZING DRIZZLE IS EXPECTED TO END AT THE LATEST BY
16Z/10AM AT METROPLEX TAF SITES WITH BAND OF PRECIP SHIFTING
SOUTHEAST. WACO WILL LIKELY CONTEND WITH LIGHT RAIN IN THE AREA
THROUGH EARLY AFTERNOON BUT TEMPS WILL BE TOO WARM THERE FOR ANY
IMPACTS.
OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING AND INTO EARLY
AFTERNOON AT METROPLEX TAF SITES. AT WACO IFR IS EXPECTED FOR A
FEW MORE HOURS...BEFORE THEY LIFT TO MVFR AS THE FRONTAL LAYER
DEEPENS. CIGS SHOULD LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
EXPECT OVERCAST SKIES TONIGHT NEAR FL100...WITH VIRGA LIKELY FROM
SNOW FALLING ALOFT. THE LOW LEVELS LOOK TOO DRY FOR SNOW TO REACH
THE SURFACE AT TAF SITES...ALTHOUGH A STRAY SNOWFLAKE WOULD BE
POSSIBLE. WILL NOT MENTION THIS POSSIBILITY IN TAFS. VFR WILL
PREVAIL OVERNIGHT AND TOMORROW MORNING WITH LIGHT N/NW WINDS.
TR.92
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 37 30 48 34 55 / 20 10 10 5 0
WACO, TX 35 30 48 32 60 / 80 10 10 5 0
PARIS, TX 37 26 46 29 48 / 20 10 10 5 0
DENTON, TX 36 29 48 30 54 / 10 10 10 5 0
MCKINNEY, TX 35 28 48 30 52 / 10 10 10 5 0
DALLAS, TX 38 31 48 35 55 / 20 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 30 10 10 5 0
CORSICANA, TX 38 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 36 31 48 32 61 / 80 10 10 5 0
MINERAL WELLS, TX 36 29 49 31 58 / 10 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/82
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
932 AM CST MON FEB 16 2015
.AVIATION...
THE DFW AREA TAFS REMAIN UNCHANGED FROM THEIR 12Z ISSUANCE.
UPDATED THE WACO (KACT) TAF TO INCLUDE A TEMPO GROUP FOR FREEZING
RAIN FROM 16 TO 17Z. THE 1530Z TEMPERATURE AT WACO WAS 34 DEGREES
WITH ONGOING LIGHT RAIN OVER MUCH OF MCLENNAN COUNTY. TEMPERATURES
ARE EXPECTED TO FALL TO 30 TO 32 DEGREES BEFORE DRIER AIR MOVES IN
AND PRECIPITATION DISSIPATES LATER THIS MORNING.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
BAND OF LIGHT TO MODERATE RAIN HAS PUSHED EAST OF TAF SITES AND
EXPECT JUST SOME LIGHT DRIZZLE TO BE THE PRIMARY PRECIPITATE THIS
MORNING. WHILE TEMPERATURES AT AFW/FTW/DFW ARE NOW 33...ANY
DRIZZLE THAT DOES FALL WOULD HAVE THE POTENTIAL TO FREEZE ON
CONTACT TO AIRPLANE SURFACES. THAT IS BECAUSE DRIZZLE DROPLETS
WOULD LIKELY BE SUPER-COOLED...SO EVEN IF AIR TEMPERATURE STAYS
AT 33...LIGHT ICING MAY BE AN ISSUE THIS MORNING THAT REQUIRES
SOME DEICING OPERATIONS. SINCE TEMPERATURES ARE EXPECTED TO REMAIN
VERY NEAR FREEZING...AND DRIZZLE WILL BE VERY LIGHT...WE DO NOT
EXPECT THE IMPACTS WITH FREEZING DRIZZLE TO BE ON THE ORDER OF
WHAT OCCURRED AT DFW A WEEK AND A HALF AGO. THE THREAT FOR DRIZZLE
AND/OR FREEZING DRIZZLE IS EXPECTED TO END AT THE LATEST BY
16Z/10AM AT METROPLEX TAF SITES WITH BAND OF PRECIP SHIFTING
SOUTHEAST. WACO WILL LIKELY CONTEND WITH LIGHT RAIN IN THE AREA
THROUGH EARLY AFTERNOON BUT TEMPS WILL BE TOO WARM THERE FOR ANY
IMPACTS.
OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING AND INTO EARLY
AFTERNOON AT METROPLEX TAF SITES. AT WACO IFR IS EXPECTED FOR A
FEW MORE HOURS...BEFORE THEY LIFT TO MVFR AS THE FRONTAL LAYER
DEEPENS. CIGS SHOULD LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
EXPECT OVERCAST SKIES TONIGHT NEAR FL100...WITH VIRGA LIKELY FROM
SNOW FALLING ALOFT. THE LOW LEVELS LOOK TOO DRY FOR SNOW TO REACH
THE SURFACE AT TAF SITES...ALTHOUGH A STRAY SNOWFLAKE WOULD BE
POSSIBLE. WILL NOT MENTION THIS POSSIBILITY IN TAFS. VFR WILL
PREVAIL OVERNIGHT AND TOMORROW MORNING WITH LIGHT N/NW WINDS.
TR.92
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 39 30 48 34 55 / 40 10 10 5 0
WACO, TX 41 30 48 32 60 / 50 10 10 5 0
PARIS, TX 36 26 46 29 48 / 70 10 10 5 0
DENTON, TX 37 29 48 30 54 / 30 10 10 5 0
MCKINNEY, TX 38 28 48 30 52 / 50 10 10 5 0
DALLAS, TX 41 31 48 35 55 / 50 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 60 10 10 5 0
CORSICANA, TX 40 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 41 31 48 32 61 / 50 10 10 5 0
MINERAL WELLS, TX 40 29 49 31 58 / 30 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
538 AM CST MON FEB 16 2015
.AVIATION...
BAND OF LIGHT TO MODERATE RAIN HAS PUSHED EAST OF TAF SITES AND
EXPECT JUST SOME LIGHT DRIZZLE TO BE THE PRIMARY PRECIPITATE THIS
MORNING. WHILE TEMPERATURES AT AFW/FTW/DFW ARE NOW 33...ANY
DRIZZLE THAT DOES FALL WOULD HAVE THE POTENTIAL TO FREEZE ON
CONTACT TO AIRPLANE SURFACES. THAT IS BECAUSE DRIZZLE DROPLETS
WOULD LIKELY BE SUPER-COOLED...SO EVEN IF AIR TEMPERATURE STAYS
AT 33...LIGHT ICING MAY BE AN ISSUE THIS MORNING THAT REQUIRES
SOME DEICING OPERATIONS. SINCE TEMPERATURES ARE EXPECTED TO REMAIN
VERY NEAR FREEZING...AND DRIZZLE WILL BE VERY LIGHT...WE DO NOT
EXPECT THE IMPACTS WITH FREEZING DRIZZLE TO BE ON THE ORDER OF
WHAT OCCURRED AT DFW A WEEK AND A HALF AGO. THE THREAT FOR DRIZZLE
AND/OR FREEZING DRIZZLE IS EXPECTED TO END AT THE LATEST BY
16Z/10AM AT METROPLEX TAF SITES WITH BAND OF PRECIP SHIFTING
SOUTHEAST. WACO WILL LIKELY CONTEND WITH LIGHT RAIN IN THE AREA
THROUGH EARLY AFTERNOON BUT TEMPS WILL BE TOO WARM THERE FOR ANY
IMPACTS.
OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING AND INTO EARLY
AFTERNOON AT METROPLEX TAF SITES. AT WACO IFR IS EXPECTED FOR A
FEW MORE HOURS...BEFORE THEY LIFT TO MVFR AS THE FRONTAL LAYER
DEEPENS. CIGS SHOULD LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
EXPECT OVERCAST SKIES TONIGHT NEAR FL100...WITH VIRGA LIKELY FROM
SNOW FALLING ALOFT. THE LOW LEVELS LOOK TOO DRY FOR SNOW TO REACH
THE SURFACE AT TAF SITES...ALTHOUGH A STRAY SNOWFLAKE WOULD BE
POSSIBLE. WILL NOT MENTION THIS POSSIBILITY IN TAFS. VFR WILL
PREVAIL OVERNIGHT AND TOMORROW MORNING WITH LIGHT N/NW WINDS.
TR.92
&&
.PREV DISCUSSION... /ISSUED 353 AM CST MON FEB 16 2015/
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 40 30 48 34 55 / 40 10 10 5 0
WACO, TX 41 30 48 32 60 / 50 10 10 5 0
PARIS, TX 36 26 46 29 48 / 70 10 10 5 0
DENTON, TX 37 29 48 30 54 / 30 10 10 5 0
MCKINNEY, TX 38 28 48 30 52 / 50 10 10 5 0
DALLAS, TX 41 31 48 35 55 / 50 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 60 10 10 5 0
CORSICANA, TX 40 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 41 31 48 32 61 / 50 10 10 5 0
MINERAL WELLS, TX 40 29 49 31 58 / 30 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ091-
092-100>102-115-116-129.
&&
$$
/
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
531 AM CST MON FEB 16 2015
.DISCUSSION...
SEE AVIATION FOR 12Z TAF ISSUANCE.
&&
.AVIATION...
COLD FRONT CURRENTLY PUSHING SOUTHWARDS QUICKER THAN EXPECTED.
FRONT IS APPROACHING CALDWELL AND NOT THAT FAR AWAY FROM COLLEGE
STATION AT THIS TIME. HAVE GONE AHEAD AND BUMPED UP FRONTAL
PASSAGE TIMING IN TAFS BY A COUPLE OF HOURS. THE HRRR HAS
PERFORMED POORLY THIS MORNING WHILE THE TEXAS TECH WRF INITIALIZED
WELL AND IS BRINGING A THIN LINE OF SHOWERS THROUGH THE AREA WITH
THE FRONT. FORECAST SOUNDINGS SHOWING THE POSSIBILITY OF THUNDER
BUT CURRENT OBS SHOWING MOST OF THE THUNDER REMAINING NORTH OF THE
FRONT. SO FOR NOW HAVE LEFT MENTION OF THUNDER OUT OF TAFS. MOST
SITES SHOULD REMAIN BORDERLINE IFR TO MVFR TODAY AFTER THE FRONTAL
PASSAGE. 23
&&
.PREV DISCUSSION... /ISSUED 343 AM CST MON FEB 16 2015/
DISCUSSION...
AT 3 AM...A STRONG COLD FRONT EXTENDED FROM NEAR SULPHUR SPRINGS
TO CORSICANA TO BROWNWOOD. THE FRONT WILL MAKE STEADY PROGRESS
SOUTH AND SHOULD REACH COLLEGE STATION BETWEEN 6-7 AM...HOUSTON
BETWEEN 10-11 AM AND CLEAR THE COAST BETWEEN NOON AND 1 PM. HIGH
TEMPERATURES WILL OCCUR THIS MORNING WITH A QUICK 15 TO 20 DEGREE
TEMPERATURE DROP BEHIND THE FRONT. PW VALUES WILL INCREASE TO
BETWEEN 1.3 AND 1.5 INCHES...BUT JET DYNAMICS NOT TOO IMPRESSIVE
SO OTHER THAN STRONG LOW LEVEL CONVERGENCE...NOT TOO MANY OTHER
PARAMETERS ARE IN PLACE TO GENERATE PRECIP. THAT SAID...THE
CONVERGENCE SHOULD BE ENOUGH TO GENERATE A LINE OF SHOWERS AND
ISOLATED THUNDERSTORMS WITH THE FRONT BUT THE QUICK MOVEMENT OF
THE FRONT WILL YIELD MEAGER RAINFALL AMOUNTS. WINDS WILL INCREASE
RAPIDLY BEHIND THE FRONT AS WELL...BUT SUSTAINED WIND SPEEDS WILL
REMAIN BELOW ADVISORY CRITERIA EXCEPT ALONG THE IMMEDIATE COAST. A
WIND ADVISORY WILL LIKELY BE ISSUED FOR THE COASTAL COUNTIES LATE
THIS AFTERNOON AS SUSTAINED WINDS WILL LIKELY REACH THE 25 MPH
THRESHOLD. FCST SOUNDINGS FOR TONIGHT SHOW A SATURATED LAYER TO
AROUND 850 MB WITH DRY AIR ABOVE THIS LAYER. THIS TYPE OF SOUNDING
GENERALLY INDICATES SOME POTENTIAL FOR VERY LIGHT RAIN OR DRIZZLE
SO WILL CARRY LOW END RAIN CHANCES THROUGH THE OVERNIGHT HOURS.
THE AIR MASS BEHIND THE FRONT IS VERY COLD AND WITH LOWER 20S
OVER OKLAHOMA FILTERING TO THE SOUTH. FEEL MIN TEMPS TONIGHT WILL
BE ON THE COLD SIDE. TRENDED A BIT COLDER THAN GUIDANCE AND A
LIGHT FREEZE WILL BE POSSIBLE NORTH OF A BRENHAM TO CONROE TO
CLEVELAND LINE. LINGERING CLOUD COVER WILL PREVAIL FOR MOST OF
TUESDAY WITH SOME THINNING OF THE CLOUD SHIELD DURING THE
AFTERNOON. HIGH PRESSURE WILL SETTLE OVER THE STATE TUES NIGHT AND
WEDNESDAY. THIS FEATURE WILL BRING CLEAR SKIES AND COLD
TEMPERATURES. A WARM UP BEGINS ON THURSDAY WITH MUCH WARMER TEMPS
EXPECTED FRI-SUN AS THE SURFACE HIGH SHIFTS EAST AND ONSHORE WINDS
RETURN. MOISTURE LEVELS ALSO INCREASE AS PW VALUES RISE TO 1.30
INCHES. FCST SOUNDINGS STILL SHOW A LARGE AMOUNT OF DRY AIR ABOVE
700 MB SO WILL STAY WITH VERY LOW END RAIN CHANCES FOR NEXT
WEEKEND. 43
MARINE...
SOUTHERLY WINDS HAVE REMAINED ABOVE SCEC CRITERIA IN THE OFFSHORE
ZONES THIS MORNING THANKS TO A RELATIVELY TIGHT PRESSURE GRADIENT. A
COLD FRONT IS PROGGED TO PUSH OFF THE COAST THIS AFTERNOON AROUND
1PM. STRONG NORTHWEST TO NORTH WINDS CAN BE EXPECTED IN ITS WAKE
WITH ADVISORY CRITERIA EASILY BEING MET. SOME GUSTS COULD APPROACH
GALE FORCE. WINDS WILL THEN FALL BELOW SCA CRITERIA TUESDAY MORNING
AROUND SUNRISE AS HIGH PRESSURE MOVES IN FROM THE NORTH. 23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 61 32 50 34 59 / 60 20 10 10 0
HOUSTON (IAH) 68 38 50 36 60 / 60 20 20 10 0
GALVESTON (GLS) 68 43 52 43 56 / 70 20 20 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA
BAY.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 AM CST
TUESDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO
THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL NOON CST TODAY FOR THE
FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO
FREEPORT 20 TO 60 NM.
&&
$$
DISCUSSION...43
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
353 AM CST MON FEB 16 2015
.DISCUSSION...
COLD FRONT CONTINUES TO MOVE THROUGH NORTH TEXAS THIS MORNING AND
IS CURRENTLY ALONG A LINE FROM NEAR TYLER TO CORSICANA TO KILLEEN.
TEMPERATURES HAVE FALLEN INTO THE 30S BEHIND THE FRONT WITH GUSTY
NORTHWEST WINDS. THE FREEZING LINE IS LOCATED FROM GAINESVILLE TO
MINERAL WELLS TO COMANCHE AND WILL SLOWLY ADVANCE EASTWARD THROUGH
THE EARLY MORNING HOURS. IT SHOULD BE LOCATED ACROSS THE NORTHWEST
PARTS OF THE METROPLEX BY SUNRISE. A LARGE AREA OF PRECIPITATION
IS ONGOING ALONG THE FRONTAL BOUNDARY ITSELF AND THIS IS PRIMARILY
RAIN. THE ONLY EXCEPTION HAS BEEN SOME SLEET OR SMALL HAIL WITH
THE STRONGER CONVECTIVE ELEMENTS BEHIND THE FRONT.
THE LEAD SHORTWAVE IN THE TROUGH OVER THE ROCKIES IS IN THE
PROCESS OF EJECTING EASTWARD ACROSS THE PLAINS THIS MORNING. THIS
WILL ALLOW THE COLD FRONT TO CONTINUE RACING SOUTHWARD
TODAY...TAKING THE PRECIPITATION WITH IT. MOST OF THE
PRECIPITATION WILL BE OUT OF THE AREA BY THE AFTERNOON HOURS. OUR
MAIN CONCERN IN THE IMMEDIATE SHORT TERM IS THE POTENTIAL FOR SOME
FREEZING DRIZZLE ACROSS THE NORTHWEST COUNTIES. LATEST HIGH
RESOLUTION GUIDANCE INDICATES AN AREA OF ISENTROPIC ASCENT IN THE
700-500MB LAYER THROUGH EARLY MORNING. THIS IS ASSOCIATED WITH THE
SHORTWAVE TROUGH MOVING THROUGH THE SOUTHERN PLAINS AND THE LIFT
ITSELF WILL LIKELY ONLY PERSIST FOR A FEW HOURS. RUC SOUNDINGS
ACROSS THE WESTERN COUNTIES SHOW SATURATED CONDITIONS DURING THIS
TIME ALTHOUGH DRYING WILL BEGIN TO OCCUR QUICKLY AFTER 12Z. WITH
WEAK ASCENT THROUGH A SATURATED LAYER...AREAS OF DRIZZLE ARE
LIKELY TO OCCUR. TEMPERATURES ARE ALREADY A FEW DEGREES COOLER
THAN PREVIOUSLY ANTICIPATED AND ARE LIKELY TO REMAIN 28 TO 30
DEGREES THROUGH 14Z ACROSS THE NORTHWEST PART OF THE CWA. THIS
SHOULD BE SUFFICIENT FOR SOME LIGHT ICING TO OCCUR MAINLY ON
BRIDGES OVER THE NEXT SEVERAL HOURS. WE HAVE ALREADY RECEIVED ONE
REPORT OF MINOR ICING ON BRIDGES IN MONTAGUE COUNTY. WE WENT AHEAD
AND ISSUED A FREEZING RAIN ADVISORY THROUGH MID MORNING MAINLY FOR
THESE MINOR ICE ACCUMULATIONS ON BRIDGES. MAIN ROADS SHOULD
CONTINUE TO BE FINE AS GROUND TEMPERATURES HAVE BEEN VERY WARM AND
ARE LIKELY TO MELT ANY LIGHT PRECIPITATION.
WITH PRECIPITATION COMING TO AN END LATER TODAY...THERE WILL BE
SOME CLEARING TO THE WEST. IT WILL BE A COLD DAY WITH HIGHS IN THE
30S AND 40S AREAWIDE AND GUSTY NORTHWEST WINDS KEEPING WIND CHILLS
IN THE 20S THROUGHOUT THE DAY. THE MAIN TROUGH OVER THE ROCKIES
WILL ACTUALLY CROSS THE AREA LATE TONIGHT INTO TUESDAY MORNING.
SKIES ARE EXPECTED TO BECOME CLOUDY AGAIN TONIGHT AND FORCING FROM
THIS TROUGH WILL ACTUALLY BE STRONGER...HOWEVER SIGNIFICANT DRYING
WILL HAVE ALREADY OCCURRED BELOW 700MB. IT WILL BE TOUGH TO GET ANY
ADDITIONAL PRECIPITATION LATE TONIGHT INTO EARLY TUESDAY BUT GIVEN
THE STRONG ASCENT WE WILL KEEP SOME 20 POPS FOR LIGHT SNOW MAINLY
ACROSS THE WESTERN COUNTIES. FLURRIES WILL BE POSSIBLE FARTHER TO
THE EAST INTO EARLY TUESDAY MORNING. NO SNOW ACCUMULATIONS ARE
EXPECTED.
TEMPERATURES ARE EXPECTED TO WARM THROUGH THE END OF THE WEEK WITH
HIGHS AGAIN NEAR 70 BY FRIDAY. ANOTHER STRONG SHORTWAVE WILL MOVE
INTO THE WESTERN U.S. BY THIS TIME AND LOW LEVEL MOISTURE WILL
BEGIN TO BE PULLED NORTHWARD IN RESPONSE. ANOTHER STRONG COLD
FRONT IS EXPECTED TO MOVE THROUGH NEXT WEEKEND...MOST LIKELY ON
SATURDAY WITH SCATTERED SHOWERS POSSIBLE LATE FRIDAY INTO EARLY
SUNDAY.
DUNN
&&
.AVIATION...
/ISSUED 154 AM CST MON FEB 16 2015/
WATCHING THE TEMPERATURE TRENDS UNFOLD UPSTREAM AND HAVE DECIDED
THAT THE FREEZING LINE WILL PROBABLY MAKE IT TO AFW BY 13Z/7AM.
RIGHT NOW BELIEVE THAT DFW WILL FALL TO 33 DEGREES BUT OBVIOUSLY
ANOTHER DEGREE DROP IS POSSIBLE AND WITHIN THE RANGE OF ERROR.
THIS IS IMPORTANT BECAUSE A LOW LEVEL TROUGH AXIS WILL MOVE
THROUGH THE METROPLEX AROUND MID-MORNING AND ALL INDICATIONS ARE
THAT THIS SUBTLE LIFT WILL PRODUCE SOME DRIZZLE. HAVE INDICATED A
PERIOD OF FREEZING DRIZZLE AT AFW FROM 13-15Z. THE DRIZZLE AT DFW
SHOULD STAY LIQUID...BUT THE PERIOD OF TIME TO BE CONCERNED ABOUT
IS FROM 13-15Z/7-9AM. ONCE THE TROUGH AXIS MOVES THROUGH THE
DRIZZLE WILL END...AND THERE IS RATHER HIGH CONFIDENCE THAT ANY OF
THIS LIGHT PRECIP WILL SHIFT EAST OF THE METROPLEX TAF SITES BY
15-16Z. THE UNCERTAINTY IS THE EXACT TEMPERATURE THIS MORNING.
HAVE ADDED VCTS TO AFW/FTW TAFS FROM 9Z-11Z FOR CLUSTER OF STORMS
THAT IS MOVING INTO REGION FROM THE WEST. THESE CELLS SHOULD STAY
NORTH AND NORTHWEST OF TAF SITES AND GRADUALLY WEAKEN OVER THE NEXT
FEW HOURS...BUT THEY WILL GET A LITTLE TOO CLOSE FOR COMFORT. WILL
MONITOR AND SEE IF I NEED TO ADD VCTS TO DFW AS WELL.
OTHERWISE IFR CIGS SHOULD PREVAIL THROUGH EARLY MORNING...LIFTING
TO MVFR BY MID-LATE MORNING AS FRONTAL LAYER DEEPENS. CIGS SHOULD
LIFT FURTHER TO VFR BY MID-LATE AFTERNOON.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 40 30 48 34 55 / 40 10 10 5 0
WACO, TX 41 30 48 32 60 / 50 10 10 5 0
PARIS, TX 36 26 46 29 48 / 70 10 10 5 0
DENTON, TX 37 29 48 30 54 / 30 10 10 5 0
MCKINNEY, TX 38 28 48 30 52 / 50 10 10 5 0
DALLAS, TX 41 31 48 35 55 / 50 10 10 5 0
TERRELL, TX 37 29 47 31 54 / 60 10 10 5 0
CORSICANA, TX 40 29 47 33 58 / 70 10 10 5 0
TEMPLE, TX 41 31 48 32 61 / 50 10 10 5 0
MINERAL WELLS, TX 40 29 49 31 58 / 30 20 20 5 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 10 AM CST THIS MORNING FOR TXZ091-
092-100>102-115-116-129.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1142 PM CST Sun Feb 15 2015
.AVIATION...
/06Z TAFS/
MVFR CIGS have moved into KABI. Cold front should be through KSJT
before 06Z, so will start with northeast winds at KSJT, and MVFR
CIGS, although the 1500 foot ceilings may lag behind the front
somewhat. Should arrive at KBBD between now and 07Z/1AM, so have
not started with MVFR CIGS there. The front is moving faster than
earlier anticipated, so have sped up the timing of the arrival of
these low clouds at KSOA and KJCT as well. Expect the MVFR
conditions to prevail through 18Z at most sites, and have
continued the trend to VFR conditions after that time at all
sites. Gusty northeast winds behind the front should persist
through 18Z as well, then diminish slowly through 06Z tomorrow
night, while remaining northeast. 20
&&
.PREV DISCUSSION... /ISSUED 938 PM CST Sun Feb 15 2015/
UPDATE...
The strong cold front has advanced south and at 915 PM extended
from the northern border of Sterling County to the northern border
of Brown county. The latest RUC13 takes this front south to a
Brownwood to Grape Creek line by Midnight, and has the front
reaching the I-10 corridor by 5-6 AM Monday. Temperatures behind
the front have already dropped into the mid 30s in our northern
counties. The showers have moved east of our counties, while
freezing drizzle has developed farther north in southwestern
Oklahoma, where temperatures have dropped below freezing. We could
have some light rain or drizzle, changing to light freezing rain
or drizzle overnight across the Big Country and roughly the
northern third of our area, where temperatures drop to or below
freezing. However, confidence is low that this will be persistent
or widespread enough to cause travel problems. Having mentioned
this, cannot rule out possibility of a little ice on elevated
surfaces and a few slick spots may develop on a few bridges and
overpasses. The latest NAM and RUC moisten the boundary layer
tonight, but are short of saturation across the area of concern
in our northern counties.
With the above considerations, not planning to issue a Winter Weather
Advisory for our northern counties at this time. However, we will
monitor the situation closely and may need to add an advisory if
conditions or expectations change. For now, will update the
forecast to reflect a little faster timing with the front, and to
adjust temperatures and winds accordingly.
19
PREV DISCUSSION... /ISSUED 722 PM CST Sun Feb 15 2015/
UPDATE...
Strong cold front has advanced south into our northern counties
and was just north of Sweetwater and Abilene at 715 PM. This
front is making a little faster progress than previously
expected, and the RUC model appears to have the best handle
on the southward progression of this front tonight. Temperatures
behind the front have already dropped into the upper 30s to lower
40s. Rain showers are occurring across the area north of I-20 and
east of an Aspermont to Abilene line. This is where we have the
highest PoPs tonight. Will have a possibility of light rain or
freezing rain across our northern counties by late tonight, as
surface temperatures drop to or just below the freezing mark.
Forecast has been updated for tonight mainly for winds based on
the RUC, and have adjusted temperatures, winds and dewpoints to
bring in line with current/recent trends in the northern part of
our area.
19
PREV DISCUSSION... /ISSUED 555 PM CST Sun Feb 15 2015/
AVIATION...
/00Z TAFS/
A strong cold front continues to move south into the area this
evening. The front is expected to make it to KABI by 02Z/8PM or
03Z/9PM this evening. Behind it, CIGS are expected to quickly
deteriorate into the MVFR category to around 1500 feet. In
addition, at the KABI terminal, -SHRA or -DZ is expected to
develop after 05Z/11PM tonight, continuing intermittently through
most of the overnight hours. Expect the precipitation to end by
early tomorrow morning, leaving MVFR CIGS behind through most of
the morning before they start to lift for the afternoon hours
tomorrow. Similar conditions expected farther south, minus the
precipitation. The front should be through KSJT and KBBD by
09Z/3AM or 10Z/4AM tonight, possibly a little earlier, and will
check the timing of the front with the next TAF forecast issuance
if the front speeds up. KSOA and KJCT can expect the front an hour
or two later. While there may be some isolated precipitation at
the southern 4 sites, do not think there will be enough to mention
in the TAFs at this time. CIGS should lift at the other sites by
18Z/12PM tomorrow as well. 20
PREV DISCUSSION... /ISSUED 251 PM CST Sun Feb 15 2015/
SHORT TERM...
(Tonight and Tomorrow)
An upper low over the central Baja Peninsula early this afternoon
will weaken as it moves to the east and is sheared into the
southwestern flow aloft of a broad upper trough positioned over
the central CONUS. A cold front associated with the large upper
trough was moving south through the northern Panhandle early this
afternoon and will enter the Big Country late this evening. By
midnight the front should be along the Interstate 20 corridor.
Temperatures for tonight will be slow to drop with temperatures
just reaching the freezing mark over the Big Country around
sunrise. Temperatures will warm quickly after sunrise over the Big
Country with only a few hours of freezing temperatures expected.
Consequently, any light rain and freezing rain mix over the Big
Country will be short-lived and will at most affect only elevated
surfaces for a few hours.
For the remainder of the forecast area south of the Big Country,
morning lows will range from the mid 30s over the central CWA and
the 40s along the Interstate 10 corridor, with any precipitation
falling being in the liquid state. The cold front will push
completely through the forecast area before noon. Rain chances
will end from north to south during the day tomorrow with
afternoon highs reaching the mid 40s over the Big Country and the
upper 40s to around 50 over the southern CWA.
15
LONG TERM...
(Monday night through Sunday)
The shortwave trough currently located over British Columbia will
dive south over the next 24-36 hours, bringing another chance
for light precipitation to the area Monday night into Tuesday
morning. Lift associated with this system does not appear all that
favorable for a significant precipitation event. However, with
additional mesoscale forcing, there should be enough ascent to
generate light precipitation across the area, mainly beginning
after midnight. Point soundings indicate cooling aloft, eroding
the warm nose by the onset of precipitation. The question is how
much dry air will need to be moistened in the lowest few
kilometers. The GFS soundings indicate that significant moistening
will need to take place, while the NAM keeps the boundary layer
nearly saturated. The latter seems to represent an observed bias
with the NAM.
Either way, after midnight, light snow (possibly mixed with some
light sleet) will be possible across much of the CWA, with light
rain confined to the northwest Hill Country. This trend is
expected to continue into Tuesday morning, with precipitation
coming to an end by midday. Accumulations are expected to be minor
(at best) with this system. A dusting of snow is possible, mainly
north of a Sterling City to Cross Plains line, with little to no
accumulations elsewhere. Temperatures are forecast to drop into
the upper 20s, but limited QPF will zap any potential for heavier
snow.
Skies will clear as we move into Tuesday afternoon/evening. Expect
afternoon temperatures to warm into the upper 40s with winds
becoming light from the west/southwest. These light winds, dry
air, and clear skies will allow temperatures to fall into the
upper 20s and lower 30s by Wednesday morning. These cold
temperatures will be a distant memory by the afternoon, as
temperatures rebound back into the lower 60s across most of West
Central TX. The warming trend will continue on Thursday, with
highs in the mid/upper 60s.
We continue to monitor a pattern change heading into the weekend.
The West Coast ridges persists, but the ridge axis shifts back
to the west as a potent trough digs south along the Great Divide.
The flow aloft becomes briefly quasi-zonal by Friday, backing to
the southwest over the weekend as the aforementioned trough digs
toward the Four Corners. This is setting the stage for another
dump of cold air across the Plains. Just how cold remains in
question, but there is good agreement in the medium range models
that a cold front will move across the area by Sunday.
Ahead of this front, the models are developing light QPF across
central TX in response to warm advection and an open gulf. Broad
isentropic ascent is expected across the region Friday and
Saturday. Low PoPs were maintained for Saturday, but may need to
added for some areas on Friday if the latest trends hold. The 12z
ECMWF is much more aggressive with the weekend cold front compared
to the GFS/DGEX, but all of these models develop some QPF across
the area at some point with this system. We`ll continue to monitor
this system as the models zero in on a favored solution.
Johnson
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 75 32 42 27 49 / 40 50 20 30 20
San Angelo 75 36 48 28 50 / 20 20 20 20 20
Junction 71 48 48 31 51 / 20 20 20 20 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
850 PM CST TUE FEB 17 2015
.UPDATE...
AS MENTIONED IN THE AFTN DISCUSSION...A MID LEVEL TROF WILL PLOW
SOUTH ACROSS THE WESTERN GREAT LAKES OVERNIGHT. IR IMAGERY SHOWS
CLOUD TOPS COOLING IN RESPONSE TO THE FORCING. THE LOW LEVELS ARE
ALREADY EXHIBITING COLD AIR ADVECTION...RESULTING IN STEEPENING
LAPSE RATES. THIS SHOULD ALL TRANSLATE INTO SOME SCATTERED LIGHT
SNOW SHOWERS. NOT EXPECTING ANY REAL ACCUMS WITH PRECIPITABLE
WATER VALUES RUNNING LESS THAN .10 INCH. THE SNOW SHOWER THREAT
SHOULD DIMINISH OR END BY SUNRISE WEDNESDAY. LOWS OVERNIGHT SHOULD
DROP TO AROUND ZERO BY SUNRISE. NO CHANGE TO THE WIND CHILL
ADVISORY...WHICH JUST COVERS THE FAR WESTERN TIER OF OUR COUNTIES
WEST OF MADISON.
&&
.AVIATION/06Z TAFS/...
LIGHT SNOW SHOWERS ARE POSSIBLE THROUGH THE NIGHT AS A STRONG MID
LEVEL TROF/SHORT WAVE DIGS ACROSS THE WESTERN GREAT LAKES AND LOW
LEVEL COLD AIR ADVECTION STEEPENS LAPSE RATES. CONDITIONS SHOULD
GENERALLY STAY VFR THROUGH THE PERIOD. HOWEVER...THERE COULD BE A
BRIEF PERIOD OF MVFR CIGS AS A SECONDARY COLD FRONT SWEEPS THROUGH
AFTER MIDNIGHT. BUT...IMPROVING CONDITIONS WOULD RETURN SHORTLY
AFTER SUNRISE. WINDS WILL BE FAIRLY STEADY OUT OF THE NORTHWEST AT
10 TO 15 MPH.
&&
.PREV DISCUSSION... /ISSUED 310 PM CST TUE FEB 17 2015/
TONIGHT AND WEDNESDAY...CONFIDENCE - HIGH.
A POTENT 500MB SHORTWAVE TROUGH WILL SWING THROUGH THE REGION LATER
TONIGHT...WITH THE VORTICITY MAXIMA JUST TO OUR SOUTHWEST. THIS
SYSTEM WILL BE COINCIDENT WITH DECENT LOW LEVEL MOISTURE ADVECTION
AND GOOD 850MB COLD AIR ADVECTION. RAP BUFKIT SOUNDINGS INDICATE LOW
LEVEL LAPSE RATES WILL STEEPEN NEARLY DRY ADIABATICALLY THIS
EVENING. WEAK ISENTROPIC OMEGA WILL LIMIT SNOW AMOUNTS TONIGHT TO
BETWEEN A FEW TENTHS UP TO A HALF INCH ACROSS THE CWA.
THE BIG STORY WILL BE THE SINKING TEMPERATURES. 850MB TEMPERATURES
WILL REACH NEAR -28C OVER THE WESTERN HALF OF OUR CWA BY 18Z
WEDNESDAY. GUSTY NORTHWEST WINDS WILL KEEP WIND CHILLS DOWN...WITH
VALUES NEAR -20 FOR OUR FAR WESTERN TIER OF COUNTIES. WITH THE
INCREASE IN WIND SPEEDS AND GOOD COLD AIR ADVECTION...ISSUED A WIND
CHILL ADVISORY FOR SAUK...IOWA...AND LAFAYETTE COUNTIES BETWEEN 9Z
TO 16Z WED. TEMPERATURES WILL STAY COLD FOR WEDNESDAY WITH HIGHS
REACHING ONLY INTO THE SINGLE DIGITS ABOVE ZERO.
WEDNESDAY NIGHT THROUGH FRIDAY...CONFIDENCE - HIGH.
ARCTIC COLD AIR WILL REMAIN ENTRENCHED OVER THE REGION THROUGH
THURSDAY NIGHT. 925H TEMPS FALL TO AROUND -25C WED NGT. HOWEVER
MIXY BOUNDARY LAYER AND POSSIBLE SOME LINGERING STRATUS WILL PREVENT
TEMPERATURE FREE FALL OVERNIGHT. NEVER THE LESS...STILL EXPECT
OVERNIGHT LOWS TO DIP TO BETWEEN -5 AND -12 CAUSING WIND CHILLS TO
DROP TO BETWEEN 20 AND 30 BELOW. A WIND CHILL ADVISORY WILL LIKELY
BE ISSUED ON WEDNESDAY FOR THIS PERIOD.
AN EVEN COLDER NIGHT LIES AHEAD FOR THURSDAY NIGHT AS LESS WIND AND
CLOUDS ARE EXPECTED. OVERNIGHT LOWS MAY DIP TO AS COLD AS -16 IN
LOW AREAS OF THE EASTERN CWA AWAY FROM THE SHORE. MORE QUESTIONABLE
HOWEVER WHETHER A WIND CHILL ADVISORY WILL BE NEEDED AS HIGH
PRESSURE RIDGE PASSING ACROSS SRN WI WILL RESULT IN DECOUPLING AND
LIGHT SFC WINDS OVERNIGHT.
CLOUDS WILL ALSO BEGIN TO INCREASE LATE IN THE NIGHT DUE TO UPSTREAM
STRONG WARM AIR ADVECTION. WEAK LAYER Q-VECTOR CONVERGENCE CLIPS
SRN WI WITH BETTER FORCING REMAINING TO THE NORTH. NEVER THE
LESS...WITH COLD DOME IN PLACE AND VIGOROUS WARM AIR
ADVECTION...WOULD NOT BE SURPRISED TO SEE MORE WIDESPREAD -SN
OVERSPREAD SRN WI ON FRI. HOWEVER FOR NOW DUE TO UNCERTAINTY WRT
STRENGTH OF LIFT AND COLUMN MOISTURE...WL KEEP POPS IN THE CHANCE
CATEGORY FOR NOW.
FRIDAY NIGHT THROUGH SATURDAY NIGHT...CONFIDENCE - MEDIUM.
SLOWER EASTWARD PROGRESS OF SHORT WAVE TROF ACROSS WI FRIDAY NIGHT
SO WL CONTINUE SMALL POPS FOR -SN AS COLUMN MOISTURE EXTENDS TO
ABOUT 10K FT. TEMPORARY ZONAL TO SOUTHWEST FLOW ALOFT EARLY IN THE
WEEKEND WILL ALLOW AREA OF STRENGTHENING LOW PRESSURE ALONG
BAROCLINIC ZONE TO MOVE FROM THE SOUTHERN PLAINS INTO THE TN AND OH
VALLEY REGION ON SAT. ECMWF HAS BEEN TRENDING FARTHER SOUTH WITH
THE AFFECTS FROM THIS SYSTEM WHILE THE GFS HAS BEEN EDGING FARTHER
NORTH. ECMWF AND GFS CONVERGING ON SIMILAR SOLUTION WHICH KEEPS
SNOW SHIELD FROM THIS SYSTEM SOUTH OF SRN WI...MORE IN LINE WITH
LATEST CMC. WINDS MAY BRIEFLY TURN TO THE NORTHEAST AFTER TROUGH
PASSAGE FRIDAY NIGHT WHICH MAY BRING SOME LIGHT LAKE EFFECT TO THE
SOUTHEAST.
SUNDAY THROUGH TUESDAY...CONFIDENCE - MEDIUM.
SHARPENING SHORT-WAVE TROF OVER ERN CONUS ASSOCIATED WITH ABOVE
SYSTEM WILL RESULT IN NORTHWEST STEERING FLOW AND COLDER TEMPS
RETURNING FOR SUNDAY AND LASTING INTO THE FIRST DAYS OF THE WEEK OF
THE 23RD. BOTH ECMWF AND GFS SHOW VIGOROUS SHORT WAVE TROF MOVING
SOUTHEAST AND AFFECTING THE WESTERN GTLAKES IN THE MON NGT/TUE
PERIOD. TEMPERATURES EARLY NEXT WEEK DO NOT LOOK TO BE AS COLD AS
WHAT IS EXPECTED THE NEXT SEVERAL DAYS...HOWEVER WILL REMAIN BELOW
NORMAL FOR LATE FEBRUARY.
AVIATION/00Z TAFS/...
500MB SHORTWAVE TROUGH WILL MOVE THROUGH THE REGION LATER
TONIGHT...SPARKING CHANCES OF LIGHT SNOW. A QUICK BURST OF MODERATE
SNOW IS POSSIBLE DUE TO THE STRENGTH OF THE POSITIVE VORTICITY
ADVECTION ASSOCIATED WITH THIS SHORTWAVE. IN GENERAL...VFR
CONDITIONS WILL PERSIST UNTIL THE LATE EVENING HOURS WHEN THE
SHORTWAVE TROUGH MOVES IN ABOUT 03Z TONIGHT. MVFR CONDITIONS WILL
BECOME MORE COMMON AS LIGHT SNOW DEVELOPS. WINDS WILL STAY FROM THE
NORTHWEST THROUGH THE EVENING AND OVERNIGHT HOURS. GUSTY WINDS OF UP
TO 25KTS ARE POSSIBLE TOMORROW AFTERNOON AS THE PRESSURE GRADIENT
TIGHTENS.
MARINE...
THE POTENTIAL FOR HIGHER WAVES ALONG THE NEARSHORE WILL INCREASE DUE
TO STRENGTHENING NORTHWEST WINDS...WITH GUSTS UP TO 25KTS DURING THE
DAY WEDNESDAY...ALONG WITH SOME BREAKS IN THE ICE ALONG THE LAKE MI
SHORE. DECIDED TO ISSUE A SMALL CRAFT ADVISORY IN EFFECT FROM 15Z
WED TO 00Z THURS DUE TO THE INCREASE IN WINDS. SOME LIGHT SNOW IS
ALSO A POTENTIAL LATER TONIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 3 AM TO 10 AM CST WEDNESDAY FOR WIZ056-
062-067.
LM...SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM CST WEDNESDAY FOR
LMZ643>646.
&&
$$
UPDATE...DAVIS
TONIGHT/WEDNESDAY AND AVIATION/MARINE...JTS
WEDNESDAY NIGHT THROUGH TUESDAY...MBK
AREA FORECAST DISCUSSION
NWS ALBANY NY
434 AM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 434 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS BELOW ZERO...AND
SOME SPOTS IN THE ADIRONDACKS CLOSE TO -20 DEGREES F.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 07Z
3KM HRRR SHOWS A BAND OF SNOW SHOWERS STILL BACK OVER CNY NEAR THE
SYRACUSE AREA BY 5 PM. WILL START TO RAISE POPS FOR WESTERN AREAS
FOR THE LATE AFTN/EARLY EVENING IN CASE THIS SPEEDS UP...BUT MOST
AREAS WON/T SEE ANY SNOW UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND CHILLS
WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS APPEAR
LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
RIDGING AT THE SURFACE WILL WEAKEN OVERNIGHT AS A LOW PRESSURE
SYSTEM APPROACHES FROM THE GREAT LAKES REGION. CIRRUS CLOUDS WILL
STREAM IN THROUGH THE EARLY MORNING OURS ALONG WITH SOME MID LEVEL
CLOUDS AHEAD OF THE APPROACHING SYSTEM. OVERALL CLOUDS WILL THICKEN
AND LOWER TODAY AS THE SYSTEM MOVES INTO THE REGION BRINGING CHANCE
OF SNOW SHOWERS TO THE AREA...MAINLY FOR AFTER 00Z/THU. KEEPING VFR
CONDITIONS WITH VCSH UNTIL COVERAGE OF SNOW SHOWERS CAN BE
DETERMINED...THEY MAY STAY JUST SCATTERED. INDICATING SCATTERED
CLOUDS AT AROUND 1500 FEET AFTER 00Z WITH THE POSSIBILITY OF A
CEILING DEVELOPING AT THAT LEVEL IF THE COVERAGE OF SNOW SHOWERS IS
GREATER THAN SCATTERED. WINDS CALM TO LIGHT AND VARIABLE THROUGH THE
PERIOD.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS MIAMI FL
430 AM EST WED FEB 18 2015
...COLD BLAST TO IMPACT SOUTH FLORIDA THROUGH FRI MORNING...
HIGHLIGHTS...
* WIND CHILL ADVISORY ISSUED FOR AREAS NORTH OF AN EVERGLADES CITY
TO BOCA LINE LATE TONIGHT-THU MORNING
* FREEZE WATCH ISSUED FOR GLADES, HENDRY, INTERIOR COLLIER
COUNTIES LATE THU NIGHT-FRI MORNING
* HIGH RISK OF RIP CURRENTS GULF BEACHES THROUGH THURSDAY
* SMALL CRAFT ADVISORY ALL LOCAL GULF AND ATLANTIC WATERS
.DISCUSSION...
A COLD FRONT WILL EXIT THE SOUTHERN TIP OF THE PENINSULA THIS
MORNING, USHERING IN A COLD AND DRY AIRMASS. TEMPS ARE ALREADY
BELOW FREEZING ACROSS THE WESTERN FLORIDA PANHANDLE. SO COLD AIR
ADVECTION WILL BE IN FULL FORCE TODAY WITH A LESS THAN 10F DEGREE
DIURNAL. THIS HOLDS HIGHS IN THE 60S MOST AREAS...EXCEPT AROUND
70F SOUTHEAST.
ANOTHER COLD FRONT OF ARCTIC ORIGIN...NOW LOCATED FROM OKLAHOMA TO
THE OHIO VALLEY...WILL SWEEP ACROSS THE STATE TONIGHT INTO EARLY
THURSDAY. EXTREMELY DRY MODIFIED ARCTIC AIR WILL POUR DOWN THE
PENINSULA WITH DEWPOINTS FORECAST TO PLUMMET INTO THE 20S...AND
POSSIBLY EVEN THE TEENS...VERY RARE FOR SOUTH FL. THICKNESS
PROFILES AND H85 OFF BOTH THE GFS AND ECMWF SUGGEST COLD WEATHER
IMPACTS WITH A FREEZE POSSIBLE ON THE COLDEST NIGHT...THU NIGHT.
HAVE ISSUED A FREEZE WATCH FOR GLADES, HENDRY, AND INTERIOR
COLLIER COUNTIES LATE THU NIGHT-EARLY FRI MORNING. GUIDANCE
SUGGESTS TEMPS DROPPING TO NEAR FREEZING ACROSS THESE LOCALES WITH
MID-UPPER 30S ELSEWHERE EXCEPT LOWER 40S ALONG THE IMMEDIATE SE
FL COAST. THERE WAS SOME THOUGHT TO LOWER TEMPS A TAD COMPARED TO
GUIDANCE AS MOS CAN SOMETIMES BE TOO WARM WITH SHALLOW COLD
AIRMASSES. HOWEVER, GIVEN THE SURFACE HIGH POSITION WITH PERHAPS
ENOUGH WIND MIXING AND THE UNCERTAINTY IN NORTHEASTERLY WIND
MODERATION TOWARDS FRI MORNING...DECIDED TO STAY CLOSE TO
GFS/ECMWF NUMBERS.
ANOTHER FACTOR WILL BE WIND CHILLS BOTH TONIGHT AND THU NIGHT AS
A BREEZE LOOKS TO PREVAIL EACH NIGHT. WINDS WILL BE SLIGHTLY
HIGHER TONIGHT COMPARED TO THU NIGHT...BUT BOTH NIGHTS WILL SEE
LOW WIND CHILLS. A WIND CHILL ADVISORY FOR SOUTH FL IS ISSUED WHEN
WIND CHILLS ARE FORECAST TO FALL TO AT OR BELOW 35F DEGREES FOR 3+
HOURS...AND THIS IS FORECAST TO OCCUR LATE TONIGHT-EARLY THU
ACROSS PALM BEACH, INTERIOR RURAL BROWARD, COLLIER, GLADES AND
HENDRY COUNTIES. SO A WIND CHILL ADVISORY HAS BEEN ISSUED FOR
THESE AREAS. ANOTHER WIND CHILL ADVISORY WILL BE NEEDED FOR THU
NIGHT-FRI MORNING...AND LIKELY EXPANDED TO COVER MORE OF SOUTH
FL...BUT THIS WILL BE ISSUED TOMORROW.
AFTER A RECORD OR NEAR RECORD COLD MORNING FRIDAY (SEE CLIMATE
SECTION BELOW), TEMPERATURES WILL QUICKLY MODERATE BY THIS
UPCOMING WEEKEND AS THE HIGH SHIFTS INTO THE ATLANTIC WITH A
RETURN TO A SE WIND FLOW...SENDING TEMPS BACK INTO THE 70S BY
SATURDAY AND SOME 80-DEGREE READINGS EARLY NEXT WEEK. GFS/ECMWF
SHOW ANOTHER COLD FRONT OF VARYING STRENGTH BY NEXT TUE OR WED.
/GREGORIA
&&
.MARINE...
DETERIORATING CONDITIONS AS NW WINDS INCREASE BEHIND A COLD FRONT.
SEAS WILL RAPIDLY BUILD...ESPECIALLY ACROSS THE GULF STREAM AND
OFFSHORE GULF WATERS. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR
ALL LOCAL GULF AND ATLANTIC WATERS EFFECTIVE THROUGH EARLY FRIDAY
MORNING.
&&
.AVIATION...
LATEST HRRR CONTINUES TO DEPICT ENHANCEMENT OF SHOWERS AND
THUNDERSTORMS CURRENTLY ACROSS THE GULF WATERS AND EXTREME
SOUTHERN FLORIDA TIP. THIS ACTIVITY SHOULD CONTINUE TO PUSH TO THE
NORTHEAST THROUGH THE MORNING AND AFFECT THE EAST COAST
SITES...PRIMARILY KFXE AND SOUTHWARD. LEFT OUT ANY MENTION OF
THUNDER FOR NOW AS IT LOOKS LIKE THUNDER SHOULD REMAIN ISOLATED.
WILL AMEND AS NECESSARY. FROPA SHOULD OCCUR AT KAPF AND KPBI OVER
THE NEXT FEW HOURS AND AROUND 10Z-12Z AT THE REMAINDER OF THE EAST
COAST SITES. GUSTY NORTHWESTERLY WINDS SHOULD THEN PREVAIL BEHIND
THE FRONT AT ALL SITES THROUGH THE AFTERNOON BEFORE SUBSIDING
SLIGHTLY AFTER 00Z. /CD
&&
.FIRE WEATHER...
RELATIVE HUMIDITIES WILL BE TAKING A DIVE TODAY AND ESPECIALLY ON
THURSDAY AS A MODIFIED ARCTIC AIRMASS SWEEPS DOWN THE PENINSULA.
THIS WILL SEND EXTREMELY LOW DEWPOINT AIR INTO SOUTH
FLORIDA...INTO THE TEENS AND 20S BY THU AFTERNOON. MIN RELATIVE
HUMIDITIES ARE FORECAST TO FALL INTO THE 30S THIS AFTERNOON AND
20S EVERYWHERE THU AFTERNOON. A BREEZE NW WIND WILL PREVAIL AS
WELL EACH DAY. HOWEVER, ERC VALUES WILL BE BORDERLINE AT BEST. AS
SUCH, HAVE NOT ISSUED A FIRE WEATHER WATCH DUE TO THE ERC
CONSTRAINT ON RED FLAG CONDITIONS. /GREGORIA
&&
.CLIMATE...
RECORD LOWS ARE POSSIBLE FRIDAY MORNING. HERE ARE THE RECORD LOWS
FOR FEB. 20TH:
WEST PALM BEACH 42F (1920 AND 1958)
FT. LAUDERDALE 40F (1958 AND 1960)
MIAMI 42F (1972)
NAPLES 39F (1960)
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 69 39 56 36 / 50 0 0 0
FORT LAUDERDALE 71 44 57 41 / 50 0 0 0
MIAMI 73 44 58 41 / 50 0 0 0
NAPLES 66 44 58 38 / 30 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR
FLZ063-066-070.
WIND CHILL ADVISORY FROM 2 AM TO 9 AM EST THURSDAY FOR FLZ063-
066>071-168.
HIGH RIP CURRENT RISK FROM 7 AM EST THIS MORNING THROUGH
THURSDAY AFTERNOON FOR FLZ069.
AM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 1 AM EST FRIDAY
FOR AMZ650-651-670-671.
GM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 1 AM EST FRIDAY
FOR GMZ656-657-676.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
106 AM EST WED FEB 18 2015
.AVIATION...
LATEST HRRR CONTINUES TO DEPICT ENHANCEMENT OF SHOWERS AND
THUNDERSTORMS CURRENTLY ACROSS THE GULF WATERS AND EXTREME
SOUTHERN FLORIDA TIP. THIS ACTIVITY SHOULD CONTINUE TO PUSH TO THE
NORTHEAST THROUGH THE MORNING AND AFFECT THE EAST COAST
SITES...PRIMARILY KFXE AND SOUTHWARD. LEFT OUT ANY MENTION OF
THUNDER FOR NOW AS IT LOOKS LIKE THUNDER SHOULD REMAIN ISOLATED.
WILL AMEND AS NECESSARY. FROPA SHOULD OCCUR AT KAPF AND KPBI OVER
THE NEXT FEW HOURS AND AROUND 10Z-12Z AT THE REMAINDER OF THE EAST
COAST SITES. GUSTY NORTHWESTERLY WINDS SHOULD THEN PREVAIL BEHIND
THE FRONT AT ALL SITES THROUGH THE AFTERNOON BEFORE SUBSIDING
SLIGHTLY AFTER 00Z.
&&
.PREV DISCUSSION... /ISSUED 948 PM EST TUE FEB 17 2015/
UPDATE...
THE 00Z SOUNDING INDICATED INCREASING INSTABILITY WITH 500 HPA
TEMPERATURES DECREASING AND THE STABILITY INDICES DECREASING
ALTHOUGH THE MID LEVEL LAPSE RATES HAVE NOT SIGNIFICANTLY
DECREASED. BUT THE OVERALL ENVIRONMENT IS STILL SUPPORTIVE OF
THUNDERSTORMS WITH A FEW STRONG GUSTS. CURRENTLY MOST OF THE
THUNDERSTORM ACTIVITY IS IN THE EASTERN GULF TO THE WEST OF THE
FLORIDA KEYS. THE EARLIER GUIDANCE INDICATED THE JET STREAM
DIPPING SOUTHWARD INTO THE FLORIDA PENINSULA TONIGHT WITH THE 00Z
SOUNDING INDICATING WINDS OVER 100 KNOTS ABOVE 200 MB AND WINDS
AROUND 60 KNOTS HAVE DESCENDED TO BELOW 500 MB.
A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH 12Z WEDNESDAY MORNING
FOR THE OFF SHORE ATLANTIC WATERS TO THE EAST OF PALM BEACH
COUNTY WITH REGIONAL WIND OBSERVATIONS INDICATING WINDS IN THE 20
TO 25 KNOT RANGE ARE LIKELY OCCURRING IN THE OFF SHORE WATERS. A
SMALL CRAFT ADVISORY WILL LIKELY BE ISSUED ON WEDNESDAY FOR ALL
REGIONAL GULF AND ATLANTIC WATERS FOR WEDNESDAY WITH INCREASING
WINDS AND HAZARDOUS SEAS EXPECTED AFTER THE FRONTAL PASSAGE ON
WEDNESDAY.
60
PREV DISCUSSION... /ISSUED 509 PM EST TUE FEB 17 2015/
DISCUSSION...
A COLD FRONT CONTINUES TO MOVE INTO THE FLORIDA PENINSULA WITH
EXTENSIVE CLOUD COVER INTO SOUTH CENTRAL FLORIDA AND ADJACENT GULF
AND ATLANTIC WATERS ALTHOUGH LIGHTNING ACTIVITY HAS BEEN ONLY
ISOLATED AND THUS FAR MAINLY LIMITED TO THE EASTERN GULF.
FOR TONIGHT...THE COLD FRONT WILL CONTINUE TO MOVE SOUTH ACROSS
THE FLORIDA PENINSULA AND ADJACENT WATERS WITH CHANCES OF SHOWERS
INCREASING LATE THIS EVENING AND OVERNIGHT. THE MOST COVERAGE OF
SHOWERS IS EXPECTED AFTER MIDNIGHT. WHILE THUNDERSTORM ACTIVITY
HAS SO FAR BEEN LIMITED THIS AFTERNOON...THE POTENTIAL WILL
INCREASE TONIGHT AS THE GUIDANCE INDICATES THE JET STREAM WILL
PASS ACROSS THE FLORIDA PENINSULA TONIGHT INTO WEDNESDAY. FORECAST
SOUNDINGS INDICATE 250 HPA WINDS REACHING IN EXCESS OF 100 KNOTS
AROUND 06Z WEDNESDAY. THIS COMBINED WITH INCREASING INSTABILITYAND
MID-LEVEL TEMPERATURES DECREASING SHOULD RESULT IN SOME
THUNDERSTORM ACTIVITY. FORECAST SOUNDINGS ALSO INDICATE WINDS
INCREASING TO THE LOWER LEVELS OVER NIGHT. THEREFORE WITH ANY
THUNDERSTORM ACTIVITY THERE COULD BE GUSTY WINDS TO NEAR 50 MPH
POSSIBLE WITH A STRONGER THUNDERSTORM.
GUIDANCE CONSISTENTLY INDICATES THE FRONT CLEARING THE REGION
ON WEDNESDAY WITH HIGH PRESSURE...INCREASING WINDS AND SIGNIFICANT COLD
AIR ADVECTION DOWN THE FLORIDA PENINSULA AS THE DAY PROGRESSES.
IN ADDITION WEDNESDAY NIGHT INTO THURSDAY MORNING A SECONDARY DRY
COLD FRONT IS FORECAST TO PASS ACROSS THE FLORIDA PENINSULA WITH
COLD AIR OF ARCTIC ORIGIN COMING DOWN THE FLORIDA PENINSULA. THE
LATEST TEMPERATURE GUIDANCE HAS BEEN VERY CONSISTENT WITH THIS
SCENARIO AND HAS BEEN WELL ADVERTISED THE LAST COUPLE OF DAYS WITH
LITTLE CHANGE IN THE FORECAST. THE COLDEST TEMPERATURE AND WIND
CHILL IMPACTS ARE EXPECTED ON WEDNESDAY NIGHT INTO THURSDAY AND
THURSDAY NIGHT INTO FRIDAY. ON WEDNESDAY NIGHT INTO
THURSDAY...STRONG WINDS ARE FORECAST ACROSS THE REGIONAL WATERS
AND THE WINDS WILL NOT LIKELY COMPLETELY DE-COUPLE OVER LAND OVER
NIGHT AS USUAL. THUS WIND CHILLS COULD BE NEAR 30 IN THE NORTHERN
INTERIOR AND POSSIBLY NEAR THE MID 30`S IN THE INTERIOR PORTIONS
OF THE NAPLES AND ATLANTIC METRO AREAS. THURSDAY NIGHT INTO
FRIDAY...REGIONAL WINDS ARE FORECAST TO DECREASE BUT TEMPERATURES
ARE FORECAST TO LOWER TO NEAR FREEZING IN THE NORTHERN INTERIOR
WEST OF LAKE OKEECHOBEE AND COULD DROP TO NEAR 40 OR UPPER 30S IN
PORTIONS OF THE NAPLES AND ATLANTIC COAST METRO AREAS. A FREEZE
WATCH MAY BE NEED FOR PORTIONS OF THE INTERIOR FOR EARLY FRIDAY
MORNING. ANY WATCHES OR WARNINGS FOR WEDNESDAY NIGHT OR THURSDAY
NIGHT WILL BE CONSIDERED DURING THE NIGHT SHIFT TONIGHT.
MARINE...
WITH THE FRONTAL PASSAGE TONIGHT DISCUSSED AT LENGTH
ABOVE...WINDS AND SEAS WILL BUILD ACROSS THE REGIONAL WATERS
TONIGHT INTO WEDNESDAY MORNING WITH SMALL CRAFT ADVISORIES LIKELY
TO BE ISSUED FOR THE LOCAL GULF AND ATLANTIC WATERS FOR WEDNESDAY MORNING.
HAZARDOUS SEAS ARE FORECAST TO BUILD ACROSS THE GULF AND ATLANTIC
WATERS STARTING AROUND 12Z WEDNESDAY AND PERSISTING THROUGH
THURSDAY NIGHT WITH CONDITIONS SLOWLY IMPROVING THEREAFTER.
FIRE WEATHER...
A STRONG COLD FRONT WILL BE MOVING THROUGH SOUTH FLORIDA LATE
TONIGHT INTO EARLY WEDNESDAY MORNING. THIS FRONT WILL BRING IN MUCH
DRIER AIR TO SOUTH FLORIDA STARTING WEDNESDAY AFTERNOON THROUGH
FRIDAY. THE RELATIVE HUMIDITY ON WEDNESDAY AFTERNOON WILL BE FALLING
INTO THE MID TO UPPER 30S FOR A COUPLE OF HOURS. HOWEVER...THE
RELATIVE HUMIDITY ON THURSDAY WILL FALL INTO THE LOWER TO MID 20S.
THE 20 FOOT WINDS WILL ALSO BE AROUND 15 MPH WITH THE ERC IN THE MID
20S. THIS WILL PUT SOUTH FLORIDA CLOSE TO THE FIRE DANGER CONDITIONS
ON THURSDAY. THEREFORE...IF THE FORECAST TREND CONDITIONS IN LATER
MODEL GUIDANCE THEN FIRE WEATHER HEADLINES WILL MORE LIKELY BE
NEEDED FOR THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 69 40 60 39 / 30 0 0 0
FORT LAUDERDALE 71 45 60 43 / 50 0 0 0
MIAMI 72 47 62 43 / 50 0 0 0
NAPLES 64 45 59 40 / 30 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR AMZ670.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
122 AM CST WED FEB 18 2015
.SHORT TERM...
320 PM CST
TONIGHT THROUGH THURSDAY...
MAIN CONCERN IS WITH BITTERLY COLD TEMPERATURES AND WIND CHILLS AS
NEAR RECORD COLD AIR MASS FOR MID TO LATE FEBRUARY IMPACTS THE AREA.
IN ADDITION...EXPECTING FAIRLY WIDESPREAD SNOW SHOWERS LATE TONIGHT
INTO WEDNESDAY MORNING.
MORNING RAOBS SHOWED HEART OF COLD AIR MASS...WITH 850 MB TEMPS OF
ABOUT -25 TO -30C FROM KINL UP TO HUDSON BAY. STRONG PV ANOMALY ON
LEADING EDGE OF THIS AIR MASS IS NOTED ON W/V IMAGERY FROM EASTERN
DAKOTAS INTO WESTERN ONTARIO AND THIS WILL MOVE OVER THE AREA
TONIGHT INTO EARLY THURSDAY. IN NEAR TERM...WILL CONTINUE TO SEE
OCCASIONAL FLURRIES...WITH LINGERING SNOW SHOWERS EXITING NW
INDIANA. FORCING FROM UPPER WAVE/PV ANOMALY AND STEEPENING OF
LAPSE RATES SHOULD RESULT IN FAIRLY WIDESPREAD SCATTERED SNOW
SHOWERS PIVOTING SOUTHEASTWARD FROM AROUND MIDNIGHT TONIGHT
THROUGH EARLY THURSDAY MORNING. SIMILAR TO PREVIOUS OCCURRENCES
WITHIN THE PAST WEEK...NOT ALL AREAS WILL SEE ACCUMULATIONS...BUT
WOULDNT BE SURPRISED IF HEAVIER SNOW SQUALLS ARE EMBEDDED WITHIN
SCATTERED SNOW SHOWER ACTIVITY...YIELDING LOCALLY 1/2 INCH TO 1
INCH ACCUMS AND SIGNIFICANTLY REDUCED VISIBILITY. COLD ADVECTION
SHOULD FORCE TEMPERATURES DOWN TO ROUGHLY 0 TO +6 RANGE BY
DAYBREAK WEDNESDAY.
TEMPERATURE TRENDS ARE TRICKY ON WEDNESDAY BECAUSE OF HOW ANOMALOUS
AIR MASS IS. MINUS MID TO UPPER 20S CELSIUS AIR MASS AT 850 MB PROGGED BY
LATE IN THE DAY IS AMONGST THE COLDEST OBSERVED AT ILX/DVN IN THE
MONTH OF FEBRUARY...AND ESPECIALLY THIS LATE IN THE MONTH. HAVE
SHOWN A VERY MINIMAL RECOVERY FROM MORNING LOWS INTO MID DAY/HIGHS
MID TO HIGH POSITIVE SINGLE DIGITS/FOLLOWED BY A FALL IN THE
AFTERNOON..BUT THIS VERY WELL COULD BE OVERDONE. BEST FORCING WILL
BE OFF TO EAST...BUT DEEP UPPER TROUGH REMAINING OVERHEAD AND STEEP
LOW LEVEL LAPSE RATES SHOULD KEEP AT LEAST ISOLATED SNOW SHOWERS AND
FLURRIES AROUND INTO EARLY WEDNESDAY AFTERNOON. STRONG LOW LEVEL
COLD ADVECTION WILL CONTINUE THROUGH WEDNESDAY NIGHT...WITH 925 MB
TEMPS IN THE MID MINUS 20S CELSIUS BY EARLY THURSDAY. THUS DESPITE HIGH
PRESSURE REMAINING WELL NORTHWEST AND PRECLUDING RADIATIONAL
COOLING...SUBZERO LOWS ARE EXPECTED CWA WIDE...AND RELATIVELY
UNIFORM RANGING FROM MID MINUS SINGLE DIGITS TO AROUND 10 BELOW.
EVEN DOWNTOWN CHICAGO SHOULD FALL TO SEVERAL DEGREES BELOW ZERO.
WILL NEED A WIND CHILL ADVISORY FOR THE ENTIRE CWA WEDNESDAY
EVENING/NIGHT THROUGH THURSDAY MORNING...WITH LOWEST VALUES
RANGING FROM 20 TO 30 BELOW ZERO.
THERMAL TROUGH WILL ONLY SLOWLY DEPART TO THE NORTHEAST ON
THURSDAY...SO AFTER BITTERLY COLD START TO DAY...CONTINUE TO
FORECAST RECORD/NEAR RECORD LOW HIGH TEMPERATURES IN THE LOW TO MID
POSITIVE SINGLE DIGITS. SEE CLIMATE SECTION FOR ADDITIONAL DETAILS.
REGARDING LAKE EFFECT POTENTIAL ON WEDNESDAY INTO WEDNESDAY
NIGHT...GUIDANCE CONTINUES TO FOCUS MAINLY EAST OF PORTER COUNTY
WITH WNW BOUNDARY LAYER FLOW. HOWEVER...WITH EXTREME COLD AIR MASS
OVER RELATIVELY MILD LAKE WATERS...COULD STILL SEE SOME MINOR
ACCUMULATIONS IN NORTHEAST PORTER COUNTY IN LIGHT MULTI-BAND SNOW
SHOWERS.
RC
&&
.LONG TERM...
355 PM CST
THURSDAY NIGHT THROUGH TUESDAY...
NO REAL END IN SIGHT TO THE COLD PATTERN...THOUGH THERE WILL BE
SOME MODERATION AT THE BEGINNING OF THE WEEKEND. THURSDAY NIGHT`S
LOWS WILL DEPEND ON HOW QUICKLY CLOUD COVER INCREASES FROM THE
WEST AND SOUTHWEST. ARCTIC HIGH WILL BE OVERHEAD FOR PART OF THE
NIGHT BEFORE SLIDING SOUTHEAST BY DAYBREAK. THERE WILL BE SLOW
WARM ADVECTION ALOFT...BUT ASSUMING SKIES REMAIN MOSTLY
CLEAR/PARTLY CLOUDY THROUGH AT LEAST PART OF
OVERNIGHT...RADIATIONAL COOLING WILL ENABLE SUBZERO LOWS CWA WIDE
AGAIN. COLDEST SPOTS IN NORTHERN IL COULD FALL TO 10 BELOW OR
SLIGHTLY LOWER. MUCH LIGHTER WINDS SHOULD PRECLUDE NEED FOR
ANOTHER WIND CHILL ADVISORY THURSDAY NIGHT.
ON FRIDAY INTO SATURDAY...BIT OF A COMPLEX SETUP WITH MODEL
VARIANCE REGARDING HANDLING MULTIPLE MID LEVEL SHORTWAVES. SOME 12Z
GUIDANCE BROUGHT ACROSS LEAD NORTHERN STREAM WAVE/CLIPPER ON
FRIDAY...FOR WHICH SLIGHT CHANCE TO LOW CHANCE (IN FAR) NORTH POPS
WERE CONTINUED. GFS OPERATIONAL/GEFS AND EUROPEAN ENSEMBLE THEN
INDICATE POTENTIAL FOR MORE WIDESPREAD PRECIPITATION FROM MID LEVEL
WAVE AND ASSOCIATED SURFACE LOW MOVING FROM SOUTHERN PLAINS TO
OHIO VALLEY ON SATURDAY INTO SUNDAY. DESPITE DRIER TREND TODAY
FROM OPERATIONAL ECMWF...OP GFS/GEFS MEAN AND INDIVIDUAL
MEMBERS/ECMWF ENSEMBLE MEAN AND SOME INDIVIDUAL MEMBERS/ALL HAVE
TRACK MORE FAVORABLE FOR WIDESPREAD SNOW AREA WIDE. FOR NOW HAVE
HIGHEST CHANCE POPS SOUTH OF INTERSTATE 80...BUT THIS PERIOD WILL
NEED TO BE WATCHED FOR HOW WELL VARIOUS SHORT WAVES
INTERACT/PHASE. HIGHS WILL MODERATE FROM NEAR/AROUND 20 ON FRIDAY
TO UPPER 20S/LOW 30S ON SATURDAY...THEN COOL BACK WELL BELOW
NORMAL FOR THE REST OF THE EXTENDED. 12Z OPERATIONAL ECMWF SHOWED
ANOTHER SHOT OF EXTREME COLD BEYOND DAY 7...WHICH ANYONE THAT IS
GROWING TIRED OF THE VERY COLD WEATHER CAN ONLY HOPE DOESNT COME
TO FRUITION.
RC
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE RECORD LOW
MAXIMUM TEMPERATURES.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE AT ALMOST ANYTIME
THROUGH WEDNESDAY.
* BEST SHOT OF MORE SUBSTANTIAL SHSN APPEARS TO BE DURING THE
PREDAWN HOURS THROUGH EARLY MORNING WEDNESDAY.
* GUSTY NORTHWEST WINDS DEVELOP WEDNESDAY MORNING AND CONTINUE
THROUGH AFTERNOON.
KJB
//DISCUSSION...UPDATED 06Z...
PERIODS OF LIGHT SNOW SHOWERS AND FLURRIES ARE EXPECTED TO MOVE
ACROSS THE AREA OVER THE NEXT COUPLE HOURS. ALTHOUGH MOST OF THESE
WILL RESULT IN VERY MINIMAL VISIBILITY RESTRICTIONS...A FEW HEAVIER
SNOW SHOWERS COULD SET UP DURING THE PREDAWN HOURS...POSSIBLY
RESULTING IN A COUPLE SHORT PERIODS OF LOW END MVFR TO IFR
VISIBILITIES. SOME MINOR ACCUMULATIONS UP TO A HALF INCH ARE
POSSIBLE THROUGH EARLY MORNING.
WINDS THROUGH THE DAY WILL BE OUT OF THE NORTHWEST. EXPECT THESE
NORTHWEST WINDS TO BECOME GUSTY...UP TO AROUND 25 KT...BY LATE
MORNING AND INTO THE AFTERNOON BEFORE ABATING BY EARLY EVENING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN TIMING OF BEST CHANCE OF MORE SUBSTANTIAL
SNOW SHOWER THREAT.
* FAIRLY HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...VFR. MODERATELY STRONG SOUTH WINDS. BECOMING MVFR AT
NIGHT WITH SNOW/IFR POSSIBLE.
SATURDAY...MVFR CIGS POSSIBLE. CHANCE OF MVFR AND -SN.
SUNDAY...MVFR CIGS POSSIBLE.
MONDAY...PRIMARILY VFR.
IZZI
&&
.MARINE...
117 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS IS STILL EXPECTED TO DEVELOP
ACROSS THE LAKE TODAY INTO TONIGHT. THE SURFACE PRESSURE GRADIENT
WILL TIGHTEN IN THE WAKE OF A SURFACE LOW...CURRENTLY SHIFTING
EASTWARD OVER THE UPPER GREAT LAKES REGION...AND AHEAD OF AN
ARCTIC SURFACE HIGH SHIFTING OVER THE NORTHERN PLAINS. IT APPEARS
THESE STRONG NORTHWEST WINDS WILL RANGE BETWEEN 30 KT AND SOME LOW
END 35 KT GALES...ESPECIALLY ACROSS THE SOUTHERN HALF OF LAKE
MICHIGAN. THE CURRENT HEADLINES FOR GALES AND FREEZING SPRAY
APPEAR TO BE ON TARGET...SO NO CHANGES ARE PLANNED AT THIS TIME.
HOWEVER...WE WILL NEED TO WATCH FOR THE POSSIBILITY OF A TIME
EXTENSION OF THE GALE/FREEZING SPRAY HEADLINE THROUGH THE NIGHT
TONIGHT...AS FORECAST GUIDANCE SUGGESTS THAT THE WINDS COULD
REMAIN ELEVATED THROUGH EARLY THURSDAY MORNING AS THE COLD ARCTIC
AIR MASS CONTINUES TO FILTER OVER THE LAKE.
WINDS WILL EASE FOR A PERIOD LATER THURSDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE BEGINS TO SHIFT OVER THE WESTERN LAKES REGION.
HOWEVER...IT APPEARS THAT WINDS WILL QUICKLY PICK UP OUT OF THE
SOUTH BY FRIDAY AS ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN
CANADA. THIS LOOKS TO RESULT IN 30 KT SOUTHERLY WINDS AND MORE
FREEZING SPRAY LAKE-WIDE ON FRIDAY.
ANOTHER STORM SYSTEM LOOKS TO DEVELOP AND SHIFT SOUTH OF THE LAKE ON
SUNDAY. DEPENDING ON THE ACTUAL STRENGTHEN OF THIS SYSTEM...IT COULD
RESULT IN A PERIOD OF STRONG NORTHERLY WINDS DOWN THE LAKE.
HOWEVER...UNCERTAINTY IS STILL SOMEWHAT HIGH WITH THIS SYSTEM.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878...6 AM WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...6 AM
WEDNESDAY TO 9 PM WEDNESDAY.
GALE WARNING...LMZ745...9 AM WEDNESDAY TO 6 PM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744...9 AM
WEDNESDAY TO 6 PM WEDNESDAY.
&&
$$
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
1134 PM CST Tue Feb 17 2015
.UPDATE...
ISSUED AT 903 PM CST TUE FEB 17 2015
Light snow is moving into the area this evening and will continue
during the overnight hours. Very difficult to see all of it on
radar given how shallow the clouds are and that all radars are
overshooting it out in northeast MO and west central IL. So, based
on observations, it appears most of the light snow will be along
and south of I-74. So will be making adjustments to pop/wx grids
to accommodate expected location of snowfall. Short term models:
HRRR seems too fast with pushing the snow through. First glance at
the NAM looks ok and keeps snow going in the east and southeast
overnight. Clouds and winds look fine, but will be making some
minor adjustments to low temps. Update will be out shortly.
&&
.SHORT TERM...(Tonight)
ISSUED AT 320 PM CST TUE FEB 17 2015
Slightly complicated forecast in the short term as the long wave
trof rotates around and through the region tonight, with a couple
shortwaves on satellite imagery. HRRR and RUC/RAPP both producing
more qpf with prev runs and clearly picking up on some snow showers
out to the west. NAM/GFS picking up on it, but mainly concentrating
on wave to the south. As a result, two additions to tonights
forecast...one with the southwest CWA in a line from roughly
Jacksonville to Springfield to Paris...potential for a few tenths of
snowfall. Up to an inch possible, but better chances will be to the
south, where the second change to the forecast is with the more
southerly wave...an inch/inch and a half are possible. Behind the
snow as morning approaches, the northwesterly winds will continue to
increase. Temperatures will mainly run slightly off the normal
diurnal curve as the cold air mass moves southward into the region.
By early morning hours, wind chills will drop to -10 to -15F NW of
the Illinois River Valley.
&&
.LONG TERM...(Wednesday through Tuesday)
ISSUED AT 320 PM CST TUE FEB 17 2015
Another reinforcing push of cold air will move into central Illinois
behind another pressure trough early Wednesday. Very cold arctic air
will result in highs only in the single digits with brisk northwest
winds 15-20 mph and gusts to around 30 mph. Went below MOS guidance
for highs Wed due to extreme variation from climatology and due to
snow cover over portions of the forecast area. As a result, wind
chill values will be below -15 F for much of the area northwest of
the Illinois River and have issued a wind chill advisory from 5 a.m.
to noon. Wind chill temperatures should be just above wind chill
criteria...-10 F or so for the afternoon, but still very cold. Winds
will settle down somewhat overnight Wednesday night causing
temperatures to drop below zero throughout central IL, but wind
chills look to drop to around -15 to -20 F and may need another wind
chill advisory.
Deep upper level trof shifts east of IL Thu night and Friday while
arctic high pressure also drifts east of IL across the Ohio river
valley Thu night and Fri morning. Temps will be slow to climb on
Friday due to mostly cloudy skies with highs in the low to mid 20s.
Have small chances of light snow Friday afternoon as moist warm
advection affects the region.
Extended models coming to better agreement on track of southern
stream storm system this weekend, with track of low passing the
southern tip of Illinois Saturday. Looks cold enough for mainly
light snow, though continue with a mix over southeast IL on Sat.
Have just slight chance of light snow Sunday and then dry across
area by Sunday evening. Highs in the low to mid 30s Sat cool off
again early next week on Sunday and Monday behind this storm
system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1134 PM CST TUE FEB 17 2015
Mainly MVFR and some IFR conditions occurring currently as a
couple of narrow bands of moderate snow moves across the TAF
sites. They have passed PIA and will pass SPI and BMI and DEC in
the next 1-2 hrs. Could be 2 more hours before CMI sees the
moderate snow pass. During the passage, vis and cigs drop to
IFR/LIFR levels, but for only a brief period. So TEMPO groups for
next 1-2 hours will have IFR type conditions with very poor vis
with snow. Once this passes, conditions will improve to VFR with
possible breaks in the clouds. So going to have broken clouds.
Believe more CU/SC will develop tomorrow and become broken across
the area. With the broken clouds, flurries will be possible, so
have included them at all sites for most of the day tomorrow. Cigs
will remain low and broken tomorrow evening. Winds will be
northwesterly through the period, but have seen brief gusty
north winds with snow band, but this will be very brief, so will
not add to TAFs. Northwest winds will become gusty again tomorrow
with gusts up to 27kts. Then winds decrease during the evening
after 00z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 5 AM to Noon CST Wednesday FOR
ILZ027>029-036-040.
&&
$$
UPDATE...Auten
SHORT TERM...HJS
LONG TERM...Onton
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS DES MOINES IA
312 AM CST WED FEB 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY BEFORE
GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO THE
REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM -18C TO
-23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY COLDER.
ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING WITH THE
NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE NORTHEAST NEAR OR
SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO NOT EXPECT MUCH OF A
WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF FOR MAX
TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY. THIS RESULTED
IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND LITTLE CHANGE
ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO REACH
WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/06Z
ISSUED AT 1130 PM CST TUE FEB 17 2015
WIND SURGE IS MAKING ITS WAY ACROSS NORTHWEST IOWA AND WILL PASS
THROUGH THE TERMINALS WITHIN THE NEXT FEW HOURS...BRINGING
STRONGER NORTHWEST WINDS THROUGH THE MORNING HOURS. A NARROW BAND
OF MVFR CIGS AND ISOLD SW- WILL ACCOMPANY THE SURGE...MAINLY AT
FOD AND ALO...BUT ANY LOW CIGS/VSBYS WILL BE AOA FL020/3SM AND
LAST ONLY AN HOUR OR TWO AT MOST. THEREAFTER...EXPECT MOSTLY CLEAR
SKIES WITH WINDS GRADUALLY DIMINISHING ON WED AFTERNOON.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-
CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-EMMET-
FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-
UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1240 AM EST WED FEB 18 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE FEB 17 2015
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER SW HUDSON BAY DOWNSTREAM OF HI AMPLITUDE RDG ALONG THE
W COAST. H5/H7/H85 TEMPS UNDER THE CORE OF THE COLDEST AIR ARND NW
ONTARIO/NE MANITOBA ARE AS LO AS -46C/-33C/-30C RESPECTIVELY.
DESPITE CONSIDERABLE ICE COVER ON LK SUP...ESPECIALLY OVER THE W...
AND THE APRCH OF A WEAK SHRTWV RDG/SOME DNVA...SOME LES CONTINUES IN
THE SN BELTS IMPACTED BY THE COLD NW LLVL FLOW LEFT IN THE WAKE OF A
DISTURBANCE WHICH PASSED LAST NGT. THE MOST OPEN WATER IS LOCATED
OVER THE SCENTRAL PART OF THE LK...SO THE MORE NMRS SN SHOWERS ARE
MOVING INTO THE E HALF OF ALGER COUNTY. LOOKING UPSTREAM...THERE IS
A SHRTWV DIGGING SSEWD THRU MANITOBA. DESPITE PWAT UNDER 0.10
INCH...THERE IS A LARGE AREA OF CLD COVER AND SOME LIGHT SN UNDER
THE DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS SHRTWV WITH 00Z-12Z H5
HGT FALLS AOA 100M AND SOME FAIRLY DEEP MSTR THRU H7 DEPICTED ON THE
12Z YPL ROAB.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON GOING HEADLINES...LES
COVERAGE/AMOUNTS AND TEMPS/LO WIND CHILLS.
TNGT...DIGGING MANITOBA SHRTWV IS PROGGED TO TRACK SSEWD THRU MN AND
INTO WI...WITH DPVA/DEEP LYR QVECTOR CNVGC ON THE CYC SIDE OF THE
TRACK OF THIS FEATURE IMPACTING UPR MI. MODEL FCST SDNGS SHOW DCRSG
STABILITY/DEEPENING MSTR LATE TODAY OVER THE W AND THEN ESPECIALLY
NEAR THE WI BORDER CLOSER TO THE TRACK OF THE DISTURBANCE INTO THE
OVERNGT. WITH THE SHRTWV PASSAGE...THERE WL ALSO BE A REINFORCING
COLD FROPA/WSHFT TO THE NNW THAT IS FCST TO DRAG H85 TEMPS AS LO AS -
30C OVER THE W BY 12Z WED. EARLIER IN THE SEASON...THIS SETUP WOULD
HAVE PRESENTED AN OPPORTUNITY FOR SOME SGNFT LES. BUT CONSIDERABLE
ICE COVER OVER LK SUP AND ABSENCE OF DGZ WITH INFLUX OF BITTERLY
COLD AIR WL GREATLY LIMIT SN TOTALS. THE BEST CHC FOR SOME HEAVIER
LES WL BE IN ALGER COUNTY...WHICH WL BE DOWNWIND OF THE MORE OPEN
WATERS OVER SCENTRAL LK SUP AND IN AREA OF ENHANCED LLVL LAND BREEZE
TYPE CNVGC EXACERBATED BY THE ICE COVER ON LK SUP. BUT WSHFT FM THE
WNW TO NNW IN THE WAKE OF THE COLD FROPA WL SHIFT THE FOCUS FOR THE
MORE NMRS SN SHOWERS FM THE E HALF OF THE COUNTY TO AREAS ARND OR
JUST W OF MUNISING. ALTHOUGH THE DOWNSLOPE NATURE OF THE NW FLOW WL
LIMIT POPS OVER THE SCENTRAL...WL CARRY SOME SCHC/CHC POPS IN THAT
AREA TO ACCOUNT FOR THE PERIOD OF DEEPER HI RH AND DYNAMIC FORCING.
SINCE THE PRES GRADIENT WL TIGHTEN IN THE WAKE OF THE SHRWV
PASSAGE/COLD FROPA...H925 WINDS ARE FCST TO INCRS TO 20-25 KTS
OVERNGT. ALSO...GROWING ICE COVER ON LK SUP WL LIMIT MODERATION OF
THE INCOMING ARCTIC AIRMASS. THESE FACTORS WL RESULT IN AT LEAST
MARGINAL WIND CHILL ADVY CONDITIONS OVER MUCH OF THE W HALF OF UPR
MI AS THE H85 TEMP TUMBLES TOWARD -30C TOWARD 12Z. ALTHOUGH WIND
SPEEDS MAY BE MARGINAL FOR THE ADVY CRITERIA... OPTED TO MAINTAIN
THE GOING HEADLINES AND ADD BARAGA/MARQUETTE COUNTIES TO THE
HEADLINE.
WED...ARRIVAL OF DNVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE
OF THE SHRTWV PASSAGE WL TEND TO SUPPRESS LINGERING SN SHOWERS
DOWNWIND OF LK SUP AND END THE PCPN COMPLETELY OVER THE SCENTRAL
DURING THE MRNG. AS THE FLOW BACKS A BIT TO THE NW AGAIN...ALGER
COUNTY WL REMAIN THE FOCUS FOR THE MORE NMRS AND HEAVIER SN
SHOWERS...ESPECIALLY IN THE MRNG. MAINTAINED WINTER WX HEADLINE FOR
ALGER COUNTY TNGT THRU WED AND WED NGT /SEE LONG TERM DISCUSSION.
WITH H85 TEMPS REMAINING NOT FAR FM -30C...EXPECT MAX TEMPS TO
STRUGGLE TO REACH ZERO...ESPCIALLY OVER THE NW HALF WHERE THE WIND
CHILL HEADLINE WL RUN UNTIL 18Z.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 440 PM EST TUE FEB 17 2015
THE OVERALL PATTERN WILL CONTINUE TO BE DOMINATED BY A MID/UPPER
LEVEL RIDGE FROM THE ERN PACIFIC INTO WRN CANADA AND A TROUGH FROM
HUDSON BAY INTO THE CENTRAL AND ERN CONUS. THIS WILL ALLOW ADDITIONAL
BOUTS OF COLD AIR TO MOVE INTO THE WRN LAKES INTO NEXT WEEK WITH
TEMPERATURES REMAINING WELL BELOW NORMAL.
WED NIGHT...THE MAIN FCST ISSUE CONTINUES TO BE THE VERY COLD AIR.
ALTHOUGH WINDS WILL GENERALLY BE LESS THAN 10 MPH...WITH AIR TEMPS
FALLING INTO THE -10 TO -20 RANGE...WIND CHILL VALUES COULD AGAIN
DROP INTO THE -20 TO -30 RANGE EVEN WITH THE WINDS ONLY AROUND 5 MPH.
THE HIGH RES MODELS WERE RELATIVELY CONSISTENT IN FOCUSING LES INTO
ALGER COUNTY DOWNSTREAM OF THE REMAINING OPEN PATCH OF WATER IN THE
DEEPEST PORTION OF LAKE SUPERIOR. FAVORABLE LOW LEVEL CONV IN THE
NARROW OPEN AREA COULD PRODUCE A HEAVIER SNOW BAND WITH ADDITIONAL
SNOW AMOUNTS IN THE 1 TO 4 INCH RANGE ARE EXPECTED.
HOWEVER...CONFIDENCE IS LOW GIVEN THE CHANGING/INCREASING AMOUNTS OF
ICE COVER.
THU AND THU NIGHT...THE ARCTIC HIGH WILL BUILD INTO THE AREA WITH
MAINLY LIGHT WINDS. EXPECT ENOUGH CLEARING FOR TEMPS TO DROP OFF
INTO THE -15 TO 25 RANGE WITH SOME LOCAL READINGS POSSIBLY DOWN TO
AROUND -30F. HOWEVER...MAINLY LIGHT/CALM WINDS SHOULD PREVAIL. ANY
REMAINING LES INTO ALGER COUNTY WILL DIMINISH AND LIFT OFFSHORE AS
WINDS BECOME SW BY EVENING.
FRI INTO FRI NIGHT...A TROUGH MOVING TOWARD THE WRN LAKES WILL
RESULT IN A BROAD WAA PATTERN THROUGH THE REGION. THE MODELS WERE IN
RELATIVELY GOOD AGREEMENT THAT DEEP LAYER ISENTROPIC ASCENT AHEAD
THIS FEATURES WILL PRODUCE SOME LIGHT SNOW. FOR NOW...POPS WERE LEFT
IN THE CHANCE RANGE...BUT WOULD EXPECT THAT IF THE TRENDS HOLD UP A
HIGHER POP LOW QPF/SNOW EVENT WILL DEVELOP WITH OVERALL SNOW AMOUNTS
OF AN INCH OR TWO. THE INCREASING SW FLOW OFF OF LAKE MICHIGAN COULD
BRING A SNOW BAND INTO THE FAR SE CWA BUT WITH THE EXTENSIVE ICE
THAT HAS DEVELOPED OVER NRN LAKE MI...CONFIDENCE IS LOW THAT IT WILL
BRING SIGNIFICANT ADDITIONAL SNOW AMOUNTS.
SAT-TUE...ANOTHER BATCH OF ARCTIC AIR WILL SLIDE INTO THE AREA BY
SUN WITH TEMPS FROM ZERO TO 10 BELOW SAT NIGHT AND IN THE SINGLE
DIGITS SUN. NW WINDS COULD BRING SOME LIGHT SNOW SHOWERS TO THE AREA
FROM ANY REMAINING GAPS IN THE ICE COVER...MAINLY OVER THE EAST
HALF. FCST UNCERTAINTY IS HIGHER BY TUE...AS THE 00Z/12Z ECMWF
REMAINED SIGNIFICANTLY MORE AGGRESSIVE WITH THE NEXT SHRTWV AND
AMOUNT OF COLD MOVING IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1239 AM EST WED FEB 18 2015
LAKE EFFECT SNOW BANDS CONTINUE OVER WESTERN LAKE SUPERIOR AND HAVE
OCCASIONALLY PRODUCED IFR CONDITIONS AT BOTH KCMX AND KIWD LATE THIS
EVENING. COLDER AIR TO MOVE INTO HE WESTERN U.P. OVERNIGHT AS ANOTHER
SURGE OF ARCTIC AIR ARRIVES WITH THE PASSAGE OF 5H TROF AXIS. THIS
WILL KEEP LES GOING FOR A WHILE WITH IFR/LOW END MVFR CONDITIONS
CONTINUING THROUGH THE NIGHT WITH IMPROVEMENT EXPECTED BY DAYBREAK AS
SUBSIDENCE STRENGTHENS. LES TO GRADUALLY END DURING THE DAYTIME HOURS
WITH CIGS IMPROVING. AT KSAW...NW FLOW NOT AS CONDUCIVE TO LOWER CIGS
AND VISIBILITIES THERE SO EXPECT MVFR CONDITIONS TO PREVAIL THERE
THROUGH THE FORECAST. THERE IS SOME CONCERN THAT SOME BLOWING AND
DRIFTING SNOW MAY PRODUCE IFR VISIBILITIES THERE DURING THE DAY AS
WINDS PICK UP A BIT AND BECOME GUSTY AT TIMES BUT HAVE LEFT THIS OUT
OF THE FORECAST AT THIS TIME. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE FEB 17 2015
WINDS WILL BE MAINLY 30 KTS OR LESS THE REST OF THE WEEK INTO NEXT
WEEKEND. THERE MAY BE A FEW GALE FORCE GUSTS IN THE VCNTY OF STRONG
BAND OF LAKE EFFECT SNOW OVER SCENTRAL LK SUPERIOR LATE TONIGHT
THROUGH WED NIGHT. HEAVY FREEZING SPRAY COULD DEVELOP IN THE LIMITED
OPEN WATER OF SCENTRAL LK SUPERIOR ON WED NIGHT. ICE COVERAGE WILL
CONTINUE TO EXPAND THROUGH THE WEEK AS ARCTIC AIRMASS SETTLES OVER
THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR MIZ006.
WIND CHILL ADVISORY FROM 4 AM EST /3 AM CST/ EARLY THIS MORNING
TO 1 PM EST /NOON CST/ THIS AFTERNOON FOR MIZ001>005-
009>011-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...RJT
MARINE...KC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 305 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT THROUGH
10 AM THIS MORNING...
LOTS TO CONCERN OURSELVES WITH OVER THE NEXT 48 HOURS... AND BEYOND.
FIRST... AS EARLIER INDICATED BY THE HRRR AND OTHER GUIDANCE... AN
AREA OF FREEZING FOG HAS FORMED OVER THE FAR SE PIEDMONT AND INTO
THE SANDHILLS... WHERE DEWPOINTS REMAIN ELEVATED WITH CALM AIR IN
PLACE. BASED ON THE LIMITED COVERAGE AREA AND BORDERLINE
VISIBILITIES... WILL CONTINUE TO ADDRESS THIS WITH SPECIAL WEATHER
STATEMENTS AND MONITOR THE FOG... WHICH THE HRRR SHOWS HOLDING AS A
SMALL AREA WHICH DRIFTS EAST THROUGH SUNRISE. SECOND... LINGERING
WET ROADS FROM LAST NIGHT`S WINTRY WEATHER HAS REFROZEN INTO AREAS
OF BLACK ICE... DESPITE SOME SUBLIMATION ESPECIALLY IN THE NW CWA
WHERE DEWPOINTS ARE FALLING EARLY THIS MORNING. WILL LEAVE THE
WINTER WEATHER ADVISORY FOR BLACK ICE IN EFFECT FOR THE ENTIRE CWA
THROUGH 10 AM... HOWEVER BASED ON PROJECTED HOURLY TEMPS... PORTIONS
OF THE NW PIEDMONT MAY NOT SURPASS THE FREEZING MARK UNTIL CLOSER TO
11 AM OR NOON... AND THUS THE ADVISORY MAY NEED TO BE EXTENDED
FORWARD IN TIME BY AN HOUR OR TWO. FINALLY... FAIR SKIES THIS
MORNING WILL GIVE WAY TO A QUICK INCREASE IN CLOUDS BY MIDDAY... AS
THE CLIPPER FRONT AND ASSOCIATED VORTICITY MAX NOW CROSSING THE OH
VALLEY AND MIDSOUTH ARE PROJECTED TO SWING THROUGH CENTRAL NC THIS
AFTERNOON. WITH A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD
OF AND WITH THE FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF
7-8 C/KM... SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND
BUFR SOUNDINGS SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP
THROUGH THE -20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME...
EXPECT A BRIEF WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE
ACROSS THE NORTH HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW
SHOWER MIX ACROSS THE SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE
FREEZING FOR MUCH OF THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH
TAPERING TO SLIGHT CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT
GIVEN THE FAST MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING
A CONVECTIVE CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER
RATES... AND WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF
INCH OF SNOW IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE
MID 30S NORTH TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY
FOR NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 305 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT THROUGH
10 AM THIS MORNING...
LOTS TO CONCERN OURSELVES WITH OVER THE NEXT 48 HOURS... AND BEYOND.
FIRST... AS EARLIER INDICATED BY THE HRRR AND OTHER GUIDANCE... AN
AREA OF FREEZING FOG HAS FORMED OVER THE FAR SE PIEDMONT AND INTO
THE SANDHILLS... WHERE DEWPOINTS REMAIN ELEVATED WITH CALM AIR IN
PLACE. BASED ON THE LIMITED COVERAGE AREA AND BORDERLINE
VISIBILITIES... WILL CONTINUE TO ADDRESS THIS WITH SPECIAL WEATHER
STATEMENTS AND MONITOR THE FOG... WHICH THE HRRR SHOWS HOLDING AS A
SMALL AREA WHICH DRIFTS EAST THROUGH SUNRISE. SECOND... LINGERING
WET ROADS FROM LAST NIGHT`S WINTRY WEATHER HAS REFROZEN INTO AREAS
OF BLACK ICE... DESPITE SOME SUBLIMATION ESPECIALLY IN THE NW CWA
WHERE DEWPOINTS ARE FALLING EARLY THIS MORNING. WILL LEAVE THE
WINTER WEATHER ADVISORY FOR BLACK ICE IN EFFECT FOR THE ENTIRE CWA
THROUGH 10 AM... HOWEVER BASED ON PROJECTED HOURLY TEMPS... PORTIONS
OF THE NW PIEDMONT MAY NOT SURPASS THE FREEZING MARK UNTIL CLOSER TO
11 AM OR NOON... AND THUS THE ADVISORY MAY NEED TO BE EXTENDED
FORWARD IN TIME BY AN HOUR OR TWO. FINALLY... FAIR SKIES THIS
MORNING WILL GIVE WAY TO A QUICK INCREASE IN CLOUDS BY MIDDAY... AS
THE CLIPPER FRONT AND ASSOCIATED VORTICITY MAX NOW CROSSING THE OH
VALLEY AND MIDSOUTH ARE PROJECTED TO SWING THROUGH CENTRAL NC THIS
AFTERNOON. WITH A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD
OF AND WITH THE FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF
7-8 C/KM... SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND
BUFR SOUNDINGS SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP
THROUGH THE -20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME...
EXPECT A BRIEF WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE
ACROSS THE NORTH HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW
SHOWER MIX ACROSS THE SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE
FREEZING FOR MUCH OF THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH
TAPERING TO SLIGHT CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT
GIVEN THE FAST MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING
A CONVECTIVE CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER
RATES... AND WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF
INCH OF SNOW IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE
MID 30S NORTH TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /WEDNESDAY NIGHT/...
AS OF 337 PM TUESDAY...
PREPARE FOR DANGEROUS LIFE THREATENING COLD.
NW WINDS 15-25 MPH WILL GUST TO 35-40 MPH WEDNESDAY NIGHT WITH
RAPIDLY CLEARING EXPECTED. VERY INTENSE COLD AIR ADVECTION WILL
LEAD TO LOWS OF 5-15 NW TO SE BY THURSDAY MORNING.
WIND CHILL ADVISORIES WILL LIKELY BE NEEDED WEDNESDAY NIGHT AND
THURSDAY WHEN WIND CHILL INDICES SHOULD RANGE BETWEEN ZERO AND 15
BELOW ZERO.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...BADGETT
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1010 PM TUESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE TONIGHT THROUGH 1000 AM
WEDNESDAY...
TONIGHT:
A WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT
THROUGH 10 AM WEDNESDAY MORNING AS MANY ROADS (ESPECIALLY UNTREATED
SECONDARY ROADS) HAVE OR WILL REFREEZE TONIGHT WITH WHATS LEFT OF
ICE/SNOW/SLEET MELT ON THEM OR REMAIN SLEET/SNOW/ICE COVERED.
THE MAIN MID AND HIGH CLOUD SHIELD IS GENERALLY PUSHING OFF TO THE
NORTH AND EAST OF THE AREA THIS EVENING. HOWEVER... WITH THE MAIN
DEEP TROUGH AXIS TO THE WEST OF THE REGION AND ANOTHER EMBEDDED S/W
LOCATED OVER OK/TX SHIFTING EAST/NORTHEASTWARD EXPECT WE WILL STILL
SEE SOME MID AND HIGH CLOUDS MOVE ACROSS THE REGION OVERNIGHT. BOTH
THE HRRR AND NAM HAVE PICKED UP ON THE FACT THAT DEWPOINTS HAVE
REMAINED HIGHER THAN EXPECTED ACROSS THE AREA THIS EVENING. BOTH THE
NAM AND HRRR SHOW SOME SORT OF WEAK BOUNDARY DROPPING SOUTHWARD OUT
OF VA LATE THIS EVENING INTO THE OVERNIGHT (SHOWN MAINLY IN
DEWPOINT FIELDS). HOWEVER... BOTH THE NAM AND HRRR SHOW THIS WEAK
BOUNDARY STALLING AS IT TRIES TO PUSH INTO SOUTHERN PORTIONS OF THE
AREA... WITH POCKETS OF DENSE FOG AND LOW CLOUDS DEVELOPING ACROSS
THE SOUTHERN PIEDMONT AND SANDHILLS. IN FACT SOME IFR TO AT TIMES
LIFR FOG HAS DEVELOPED ACROSS THE SOUTHERN PIEDMONT ALREADY.
THUS... WE PLAN ON RAISING LOW TEMPS ACROSS SOUTHERN PORTIONS OF THE
AREA THIS EVENING AND PARTS OF THE COASTAL PLAIN. GIVEN WE ALREADY
HAVE A WINTER WEATHER ADVISORY FOR BLACK ICE OUT FOR THE ENTIRE
AREA... DO NOT PLAN ON ISSUING ANY ADDITIONAL HEADLINES FOR
THE POSSIBILITY OF SOME POCKETS OF FREEZING FOG. EXPECT LOW TEMPS TO
RANGE FROM THE UPPER TEENS NORTH TO THE MID TO UPPER 20S SOUTH.
WEDNESDAY:
IT APPEARS THAT A VERY BRIEF WINDOW OF TIME FOR SOME MODERATION IN
TEMPERATURES WILL OCCUR WEDNESDAY BEFORE THE BOTTOM LITERALLY
FALLS OUT. HOWEVER... STRONG HEIGHT FALLS OUT AHEAD OF THE
APPROACHING LEAD VORTICITY MAXIMUM WILL QUICKLY LEAD TO INCREASING
CLOUDINESS AND WILL SHUT DOWN THE WARMING IN THE PIEDMONT. JUST AS
WITH THE ARCTIC FRONT THAT PASSED THROUGH THE REGION LAST
WEEKEND... THERE IS A CHANCE OF SHOWERS WITH THIS FRONT. THE BEST
CHANCE OF SHOWERS APPEARS TO THE FOR THE NORTHERN AREAS OF THE
PIEDMONT... FROM THE TRIAD TO THE TRIANGLE AREAS... BETWEEN NOON
AND 500 PM. A SHORT PERIOD OF LIFT ALONG WITH STEEPENING LAPSE
RATES BETWEEN THE SURFACE AND H7 AND MOISTENING FROM THE SURFACE
THROUGH THE -15/-20C LEVEL JUSTIFIES GOOD CHANCES OF SHOWERS IN
THESE AREAS. SATURATION AND LIFT WILL BE LESS TO THE SOUTH AND
EAST WHERE ONLY SLIGHT CHANCES WILL BE FORECAST. THE TEMPERATURE
PROFILES SUGGEST SNOW SHOWERS AS THE MAIN PRECIPITATION TYPE.
HOWEVER... THE BOUNDARY LAYER SHOULD REVEAL TEMPERATURES
APPROACHING 40 BRIEFLY BEFORE THE FRONTAL PASSAGE. THEREFORE...
SNOW ACCUMULATIONS ARE NOT ANTICIPATED OTHER THAN POSSIBLY A LIGHT
DUSTING (UNDER A HALF INCH) IN HEAVIER BUT BRIEF SHOWERS... AND
CONFINED TO THE NORTHERN PIEDMONT AS MENTIONED BEFORE. HIGHS MID
30S NW TO MID 40S SE... FALLING LATE AFTERNOON IN THE NW.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
AS OF 337 PM TUESDAY...
...PREPARE FOR DANGEROUS LIFE THREATENING COLD...
NW WINDS 15-25 MPH WILL GUST TO 35-40 MPH WEDNESDAY NIGHT WITH
RAPIDLY CLEARING EXPECTED. VERY INTENSE COLD AIR ADVECTION WILL
LEAD TO LOWS OF 5-15 NW TO SE BY THURSDAY MORNING.
WIND CHILL ADVISORIES WILL LIKELY BE NEEDED WEDNESDAY NIGHT AND
THURSDAY WHEN WIND CHILL INDICES SHOULD RANGE BETWEEN ZERO AND 15
BELOW ZERO.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...RAH
SHORT TERM...BADGETT
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1235 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 1010 PM TUESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE TONIGHT THROUGH 1000 AM
WEDNESDAY...
TONIGHT:
A WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT
THROUGH 10 AM WEDNESDAY MORNING AS MANY ROADS (ESPECIALLY UNTREATED
SECONDARY ROADS) HAVE OR WILL REFREEZE TONIGHT WITH WHATS LEFT OF
ICE/SNOW/SLEET MELT ON THEM OR REMAIN SLEET/SNOW/ICE COVERED.
THE MAIN MID AND HIGH CLOUD SHIELD IS GENERALLY PUSHING OFF TO THE
NORTH AND EAST OF THE AREA THIS EVENING. HOWEVER... WITH THE MAIN
DEEP TROUGH AXIS TO THE WEST OF THE REGION AND ANOTHER EMBEDDED S/W
LOCATED OVER OK/TX SHIFTING EAST/NORTHEASTWARD EXPECT WE WILL STILL
SEE SOME MID AND HIGH CLOUDS MOVE ACROSS THE REGION OVERNIGHT. BOTH
THE HRRR AND NAM HAVE PICKED UP ON THE FACT THAT DEWPOINTS HAVE
REMAINED HIGHER THAN EXPECTED ACROSS THE AREA THIS EVENING. BOTH THE
NAM AND HRRR SHOW SOME SORT OF WEAK BOUNDARY DROPPING SOUTHWARD OUT
OF VA LATE THIS EVENING INTO THE OVERNIGHT (SHOWN MAINLY IN
DEWPOINT FIELDS). HOWEVER... BOTH THE NAM AND HRRR SHOW THIS WEAK
BOUNDARY STALLING AS IT TRIES TO PUSH INTO SOUTHERN PORTIONS OF THE
AREA... WITH POCKETS OF DENSE FOG AND LOW CLOUDS DEVELOPING ACROSS
THE SOUTHERN PIEDMONT AND SANDHILLS. IN FACT SOME IFR TO AT TIMES
LIFR FOG HAS DEVELOPED ACROSS THE SOUTHERN PIEDMONT ALREADY.
THUS... WE PLAN ON RAISING LOW TEMPS ACROSS SOUTHERN PORTIONS OF THE
AREA THIS EVENING AND PARTS OF THE COASTAL PLAIN. GIVEN WE ALREADY
HAVE A WINTER WEATHER ADVISORY FOR BLACK ICE OUT FOR THE ENTIRE
AREA... DO NOT PLAN ON ISSUING ANY ADDITIONAL HEADLINES FOR
THE POSSIBILITY OF SOME POCKETS OF FREEZING FOG. EXPECT LOW TEMPS TO
RANGE FROM THE UPPER TEENS NORTH TO THE MID TO UPPER 20S SOUTH.
WEDNESDAY:
IT APPEARS THAT A VERY BRIEF WINDOW OF TIME FOR SOME MODERATION IN
TEMPERATURES WILL OCCUR WEDNESDAY BEFORE THE BOTTOM LITERALLY
FALLS OUT. HOWEVER... STRONG HEIGHT FALLS OUT AHEAD OF THE
APPROACHING LEAD VORTICITY MAXIMUM WILL QUICKLY LEAD TO INCREASING
CLOUDINESS AND WILL SHUT DOWN THE WARMING IN THE PIEDMONT. JUST AS
WITH THE ARCTIC FRONT THAT PASSED THROUGH THE REGION LAST
WEEKEND... THERE IS A CHANCE OF SHOWERS WITH THIS FRONT. THE BEST
CHANCE OF SHOWERS APPEARS TO THE FOR THE NORTHERN AREAS OF THE
PIEDMONT... FROM THE TRIAD TO THE TRIANGLE AREAS... BETWEEN NOON
AND 500 PM. A SHORT PERIOD OF LIFT ALONG WITH STEEPENING LAPSE
RATES BETWEEN THE SURFACE AND H7 AND MOISTENING FROM THE SURFACE
THROUGH THE -15/-20C LEVEL JUSTIFIES GOOD CHANCES OF SHOWERS IN
THESE AREAS. SATURATION AND LIFT WILL BE LESS TO THE SOUTH AND
EAST WHERE ONLY SLIGHT CHANCES WILL BE FORECAST. THE TEMPERATURE
PROFILES SUGGEST SNOW SHOWERS AS THE MAIN PRECIPITATION TYPE.
HOWEVER... THE BOUNDARY LAYER SHOULD REVEAL TEMPERATURES
APPROACHING 40 BRIEFLY BEFORE THE FRONTAL PASSAGE. THEREFORE...
SNOW ACCUMULATIONS ARE NOT ANTICIPATED OTHER THAN POSSIBLY A LIGHT
DUSTING (UNDER A HALF INCH) IN HEAVIER BUT BRIEF SHOWERS... AND
CONFINED TO THE NORTHERN PIEDMONT AS MENTIONED BEFORE. HIGHS MID
30S NW TO MID 40S SE... FALLING LATE AFTERNOON IN THE NW.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
AS OF 337 PM TUESDAY...
...PREPARE FOR DANGEROUS LIFE THREATENING COLD...
NW WINDS 15-25 MPH WILL GUST TO 35-40 MPH WEDNESDAY NIGHT WITH
RAPIDLY CLEARING EXPECTED. VERY INTENSE COLD AIR ADVECTION WILL
LEAD TO LOWS OF 5-15 NW TO SE BY THURSDAY MORNING.
WIND CHILL ADVISORIES WILL LIKELY BE NEEDED WEDNESDAY NIGHT AND
THURSDAY WHEN WIND CHILL INDICES SHOULD RANGE BETWEEN ZERO AND 15
BELOW ZERO.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 300 PM TUESDAY...
...POTENTIALLY HISTORIC ARCTIC AIR MASS WILL CONTINUE TO BE IN
PLACE WITH RECORD LOW/LOW MAXIMUM TEMPERATURES EXPECTED
THURSDAY...THURSDAY NIGHT...FRIDAY AND POSSIBLY FRIDAY NIGHT...
THIS COLD WAVE SHOULD RIVAL THE COLD WAVES THAT HAVE OCCURRED IN
FEBRUARY... POTENTLY SETTING MONTHLY COLD RECORDS AS WELL.
THURSDAY THROUGH FRIDAY NIGHT: THIS PART OF THE FORECAST IS EXPECTED
TO BE DRY WITH RECORD SETTING TEMPERATURES. THE UPPER LEVEL HIGH
WILL REMAIN OVER SOUTHERN ONTARIO AND NEW ENGLAND...WITH THE TROUGH
EXTENDING SOUTH THROUGH THE MID-ATLANTIC...SLOWLY PROGRESSING
EASTWARD OFF THE COAST. MEANWHILE AT THE SURFACE...THE COASTAL LOW
WILL CONTINUE ITS NORTHEAST TREK AS THE ARCTIC HIGH BUILDS INTO THE
REGION. SUBSIDENCE UNDER THE NW FLOW AS THE HIGH BUILDS IN WILL KEEP
CENTRAL NC DRY...BUT BITTER COLD. THE TIGHT PRESSURE GRADIENT
BETWEEN THE EXITING LOW AND APPROACHING HIGH WILL RESULT IN FAIRLY
DESCENT WINDS IN THE 10-20 MPH RANGE ON THURSDAY. THE WINDS WILL
ABATE THURSDAY NIGHT AS THE HIGH MOVES OVER THE AREA...WITH
GENERALLY LIGHT AND VARIABLE WINDS THROUGH FRIDAY NIGHT.
TEMPERATURES: WITH HIGHS ON THURSDAY ALREADY AS LOW AS THE MID TEENS
IN THE NORTH TO MID 20S SOUTH...THE WIND MAY STILL PRODUCE WIND
CHILLS BELOW ZERO FOR MUCH OF THE DAY THURSDAY. THURSDAY NIGHT
LOWS SHOULD DIP TO BETWEEN 0 AND 5 NW TO NEAR 10 SE. SOME SUB-ZERO
READINGS WILL BE POSSIBLE IN THE PIEDMONT WHERE THE ICE/SNOW PACK
REMAINS. FAIRLY HIGH CONFIDENCE THAT HIGHS ON FRIDAY WILL REMAIN
BELOW FREEZING...MID 20S NORTH TO UPPER 20S SOUTH. LOWS SHOULD
REBOUND SLIGHTLY ON FRIDAY NIGHT...MAINLY IN THE 10-15 DEGREE
RANGE BUT STILL CLOSE TO RECORD VALUES (SEE CLIMATE SECTION
BELOW).
SATURDAY AND SUNDAY: THERE IS SLIGHTLY BETTER AGREEMENT BETWEEN THE
MODELS FOR THE WEEKEND...HOWEVER CONFIDENCE IS STILL LOW ON HOW MUCH
AND WHAT TYPE OF PRECIPITATION WE WILL SEE AND WHEN IT WILL OCCUR.
THERE IS A CHANCE THAT A COLD AIR WEDGE WILL SET UP OVER THE NC
PIEDMONT ON SATURDAY...AND WITH AN APPROACHING LOW PRESSURE SYSTEM
FROM THE WEST...EXPECT BEST CHANCES FOR PRECIP TO BE ACROSS THE NW
ON SATURDAY...WITH THE SANDHILLS LIKELY REMAINING DRY. FREEZING
RAIN AND/OR SLEET MAY OCCUR IF THE PRECIPIATION CAN SNEAK INTO
THE NW PIEDMONT BEFORE THE ARCTIC AIR RETREATS. THIS IS BECOMING
AN INCREASING POSSIBILITY. WE WILL HAVE TO KEEP WATCHING THIS ONE
FOR ICING POTENTIAL.
AS OF THE LATEST MODEL RUNS...SUNDAY AND SUNDAY NIGHT LOOK TO BE
THE WETTEST AS THE COLD FRONT APPROACHES AND MOVES THROUGH NC.
RAIN IS PREFERRED... BUT MODELS MAY BE BLOWING AWAY THE EXTENSIVE
COLD AIR TOO SOON. TEMPS WILL BE DIFFICULT TO FORECAST GIVEN THE
UNCERTAINTY OF THE WEDGES EXISTENCE AND HOW LONG/WHERE IT WILL
LINGER. BOTH MODELS AGREE THAT THE COLD FRONT WILL BE MOST OF THE
WAY THROUGH CENTRAL NC BY 12Z MONDAY. FOR NOW...EXPECT HIGHS IN
THE 30S NORTHWEST TO MID 40S SOUTHEAST ON SATURDAY...INCREASING
INTO THE 40S AND 50S ON SUNDAY.
MONDAY AND TUESDAY: THE PRECIPITATION SHOULD MOVE OUT OF THE AREA
WITH THE FRONT ON MONDAY...WITH HIGH PRESSURE BUILDING INTO THE
REGION BEHIND IT. COOLER TEMPERATURES WILL RETURN EARLY NEXT WEEK
WITH HIGHS MAINLY IN THE LOW TO MID 40S AND LOWS IN THE MID 30S TO
AROUND 30 DEGREES.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1235 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING (BEFORE DAYBREAK)... A PERIOD OF MVFR CIGS AND
SCATTERED SNOW SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING...
AND STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF
VALID PERIOD.
AREAS OF MVFR FOG HAVE DEVELOPED OVER THE SOUTHERN SECTIONS OF
CENTRAL NC IN THE LAST FEW HOURS. LATEST GUIDANCE SUPPORTS A PERIOD
OF IFR/LIFR FOG AT FAY EARLY THIS MORNING. VFR CONDITIONS ELSEWHERE
THIS MORNING. A CLIPPER COLD FRONT WILL SWEEP ACROSS THE AREA THIS
AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT INT/GSO...
20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD (LIKELY AROUND
2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS IS EXPECTED WITH
FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL INCREASE IN THE FEW
HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN STRONG AND GUSTY AS THEY
SHIFT TO NW BEHIND THE FRONT... LASTING THROUGH 06Z. VFR CIGS/VSBYS
ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 06Z EARLY THU MORNING: BRISK AND OCCASIONALLY GUSTY
NW SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE
EXPECTED TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE
BUILDING IN. ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW
WILL BRING LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN
THE NW EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR
CONDITIONS AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM
FRONT TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...RAH
SHORT TERM...BADGETT
LONG TERM...KC
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1215 AM EST WED FEB 18 2015
.SYNOPSIS...
ANOTHER ARCTIC FRONT WILL CROSS THE AREA FROM WEST TO EAST THIS
EVENING INTO WEDNESDAY. ARCTIC HIGH PRESSURE WILL BE OVERHEAD BY
FRIDAY MORNING. THE NEXT COLD FRONT WILL DROP ACROSS THE GREAT
LAKES ON SATURDAY. A WAVE OF LOW PRESSURE MAY DEVELOP ON THE
FRONT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ENHANCED AREA OF SNOWFALL CONTINUES TO MOVE TO THE EAST NORTHEAST
ONTO LAKE ERIE THIS EVENING. RUC MODEL INDICATES THIS TREND WILL
CONTINUE. HOWEVER WE WILL NEED TO MONITOR NE OHIO INTO NW PA FOR A
BAND OF SLIGHTLY HEAVIER SNOWFALL. FORTUNATELY THIS AREA OF OF
STEADY LIGHT SNOW SHOULD KEEP MOVING AND LIMIT AMOUNTS. STILL
LOOKS LIKE AROUND AN INCH WILL BE THE HIGH SIDE FOR ACCUMULATIONS.
THESE HEAVIER AMOUNTS WILL LIKELY BE CLOSER TO THE
LAKESHORE...ESPECIALLY NEAR TOLEDO AND ACROSS EXTREME NE OHIO INTO
NW PA.
TEMPERATURES CONTINUE TO WARM SLIGHTLY AHEAD OF THE ARCTIC
BOUNDARY THIS EVENING. THE BOUNDARY WAS LOCATED FROM NEAR THE
THUMB OF MICHIGAN SOUTHWEST TO NEAR THE INDIANA/OHIO BORDER AS OF
03Z. THIS BOUNDARY WILL CONTINUE EASTWARD THROUGH THE OVERNIGHT
WITH TEMPERATURES DROPPING BACK INTO THE SINGLE DIGITS. THIS WILL
ALLOW WIND CHILL TEMPERATURES TO DIP TO AROUND 10 DEGREES BELOW
ZERO AROUND SUNRISE. SO IT WILL BE A CLOSE CALL FOR THE NEED OF A
WIND CHILL ADVISORY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
THE FLOW WILL BE SOUTHWEST WEDNESDAY MORNING WITH PLENTY OF
MOISTURE AROUND...SO WILL KEEP CHANCE POPS. GOING WITH LIKELY FOR
THE SNOW BELT IN THE AFTERNOON AS THE FLOW BECOMES WNW WEDNESDAY
AFTERNOON. CONTINUING CHANCE POPS EVERYWHERE ELSE AS THE UPPER TROF
MOVES THROUGH.
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE SNOW BELT HAS THE
BEST CHANCE FOR SNOW WITH LOW POP CHANCES EVERYWHERE ELSE DECREASING
WITH TIME AS THE AIRMASS DRIES OUT AND THE HIGH STARTS BUILDING IN
FROM THE WEST. ON THE EDGE ABOUT THE AMOUNTS IN THE SNOW BELT. THE
NW FLOW IS USUALLY NOT THAT GOOD FOR SIGNIFICANT SNOWFALL AMOUNTS
EXCEPT OVER INLAND NW PA. HOWEVER...WITH THE AIRMASS SO DRY AND LAKE
ERIE FROZEN WE WILL NEED HELP FROM OTHER LAKES...EVEN FOR NW PA. WILL
CONTINUE TO MONITOR THIS THREAT.
DRY FRIDAY AND THEN A CHANCE OF SNOW FRIDAY NIGHT AS THE NEXT SYSTEM
APPROACHES. AT THIS TIME THE TIMING IS IN QUESTION BUT WILL NOT PUT
ANY RESOLUTION IN UNTIL THE TRENDS BECOME CLEARER.
THE MAIN THREAT WITH THIS NEXT SURGE OF COLD AIR WILL BE WIND
CHILLS. AT THIS TIME IT SEEMS LIKE A WIND CHILL ADVISORY WILL BE
GOOD ENOUGH. THE THREAT FOR NEEDING THIS HEADLINE WILL START
WEDNESDAY EVE AND LAST INTO FRIDAY MORNING. DID NOT ISSUE A
HEADLINE YET AS SOME QUESTIONS TO THE TIMING OF THE TEMPERATURE
DECREASE ETC. AT THIS TIME NOT THINKING WE WILL GET INTO WIND
CHILL WARNING CRITERIA OVER THE ENTIRE AREA...JUST SOME LOCATIONS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE MODELS CONTINUE TO JUMP BACK AND FORTH WITH INCONSISTENCY ON
TIMING THE PASSAGE OF THE ARCTIC FRONT SAT NIGHT AND THE STRENGTH OF
A POSSIBLE LOW ALONG THE FRONT. NOW THE GFS IS SHOWING MORE OF A LOW
AND SLOWER FRONTAL PASSAGE TIMING. WILL CONTINUE TO AVERAGE THE
MODELS FOR THE FORECAST WITH MAINLY LAKE EFFECT BY LATE SUN/SUN
NIGHT.
HIGH PRESSURE EXPECTED TO BE OVER THE AREA FOR DRY CONDITIONS ON
MON. ECMWF AGAIN DIGS SHARPER TROUGH WITH NEXT SYSTEM FOR TUE WITH
STRONGER LOW. ONCE AGAIN...QUESTION THIS SO WILL SIDE A LITTLE MORE
WITH GFS WHICH STILL BRINGS MOISTURE AND ANOTHER THREAT FOR SNOW
INTO THE AREA WITH LESS WARMING.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
SCATTERED SNOW SHOWERS ACROSS NORTH CENTRAL OHIO CONTINUE TO MOVE
EAST TOWARDS NORTHWEST PENNSYLVANIA. VISIBILITIES IN SNOW RANGE FROM
MVFR TO BRIEF IFR...ESPECIALLY FARTHER TO THE NORTH. SNOW WILL
DIMINISH MOST AREAS BY 10Z AND CEILINGS MAY EVEN LIFT ABOVE 4K FEET
FOR A PERIOD OF TIME ON WEDNESDAY MORNING. A TROUGH DEEPENS OVER THE
AREA ON WEDNESDAY AFTERNOON WITH AN ARCTIC FRONT MOVING THROUGH
BRINGING A GOOD BURST OF SNOW TO MOST TAF SITES WEDNESDAY AFTERNOON
INTO WEDNESDAY EVENING. THE SNOW WILL LAST LONGEST WHERE BETTER
MOISTURE IS AVAILABLE AT THE EASTERN TAF SITES. BROUGHT IFR
VISIBILITIES INTO ALL SITES AS THE FRONT COMES THROUGH BUT COULD
DROP TO A HALF MILE OR LESS FOR A SHORT PERIOD. WESTERLY WINDS
WILL INCREASE AHEAD OF THE FRONT WITH GUSTS OF 20-25
KNOTS...SHIFTING TO NORTHWEST WITH THE FRONTAL PASSAGE.
.OUTLOOK...NON VFR LINGERING INTO WEDNESDAY EVENING THEN MAINLY
SNOWBELT THU. NON VFR CONDITIONS RETURN FRIDAY NIGHT AND CONTINUE
INTO SUNDAY.
&&
.MARINE...
THE NEXT ARCTIC FRONT WILL GRADUALLY TURN SW WINDS TO NW LATE
TONIGHT THRU WED NIGHT. A TROUGH HANGING BACK INTO THE EASTERN LAKES
WILL KEEP THE FLOW DISRUPTED ENOUGH TO KEEP SPEEDS MOSTLY IN A 10 TO
20 KNOT RANGE UNTIL THU WHEN 15 TO 25 KNOTS MAY BE MORE COMMON. HIGH
PRESSURE CROSSES OH ON FRI TO PRODUCE A LIGHT FLOW THEN WINDS BACK
TO THE SSW FOR FRI NIGHT INTO SAT AHEAD OF THE NEXT ARCTIC FRONT
THAT SHOULD CROSS THE LAKE SAT NIGHT VEERING THE WINDS BACK TO NW AT
10 TO 20 KNOTS FOR SUN.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...MULLEN
SHORT TERM...KIELTYKA
LONG TERM...ADAMS
AVIATION...KEC
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1135 PM CST TUE FEB 17 2015
.UPDATE...FOR 06Z AVIATION.
&&
.AVIATION...06Z TAF DISCUSSION.
MAINLY VFR CONDITIONS AT ISSUANCE BUT CIGS ARE GOING TO START
FALLING OVER THE NEXT FEW HOURS AS A CLIPPER MOVES INTO THE AREA.
SNOWS WILL LIKELY DROP VIS FOR A FEW HOURS HOURS AROUND SUNRISE TO
AT LEAST MVFR. FLURRIES COULD LINGER AT KCSV INTO THE EARLY
AFTERNOON HOURS...BUT SNOWS SHOULD END AT KCKV AND KBNA BY 14-15Z.
BEHIND THE FRONT WINDS WILL PICK UP. BY 12Z GUSTS WILL BEGIN AT
KCKV...AND SPREAD ACROSS THE MID-STATE. NW GUSTS OF 20-25 KTS ARE
LIKELY.
UNGER
&&
.PREV DISCUSSION... /ISSUED 937 PM CST TUE FEB 17 2015/
UPDATE...LATEST HRRR CONTINUES TO BRING A BAND OF REFLECTIVITY
ACROSS MAINLY NORTHERN MIDDLE TENNESSEE AND THE PLATEAU
OVERNIGHT. BEST ESTIMATES FOR TIMING ARE CKV AROUND 08Z, BNA
AROUND 09Z, AND CSV AROUND 11Z. ENHANCES ECHOES WITHIN THE LARGER
BAND SUGGEST THE HRRR IS HONING IN ON SOME CONVECTIVE POTENTIAL,
SO BRIEF PERIODS OF HEAVIER SNOW ARE POSSIBLE, ESPECIALLY NORTH OF
I-40. HAVE ALREADY MADE SOME ADJUSTMENTS TO THE GRIDS BASED ON
EARLIER RUNS OF THE HRRR AND WILL SEND OUT AN UPDATE SHORTLY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR TNZ005>011-
023>034-056>066-075-077>080-093>095.
&&
$$
27
AREA FORECAST DISCUSSION
NWS ALBANY NY
916 AM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND CHILLS
WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS APPEAR
LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
CIRRUS CLOUDS WILL STREAM IN THROUGH THE DAY ALONG WITH SOME MID
LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL CLOUDS WILL
THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE COLD FRONT MOVES
INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS TO THE AREA...MAINLY
AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH VCSH UNTIL AROUND
06Z...WHEN MANY AREAS SHOULD SEE SOME INTERMITTENT SNOW OR SNOW
SHOWERS. MVFR CEILINGS AND VISIBILITIES SHOULD ACCOMPANY THE SNOW.
WINDS CALM TO LIGHT AND VARIABLE THROUGH THE PERIOD.
OUTLOOK... WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT-SUN:
MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
630 AM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 630 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS BELOW ZERO...AND
SOME SPOTS IN THE ADIRONDACKS CLOSE TO -20 DEGREES F.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND CHILLS
WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS APPEAR
LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
CIRRUS CLOUDS WILL STREAM IN THROUGH THE DAY ALONG WITH SOME MID
LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL CLOUDS WILL
THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE COLD FRONT MOVES
INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS TO THE AREA...MAINLY
AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH VCSH UNTIL AROUND
06Z...WHEN MANY AREAS SHOULD SEE SOME INTERMITTENT SNOW OR SNOW
SHOWERS. MVFR CEILINGS AND VISIBILITIES SHOULD ACCOMPANY THE SNOW.
WINDS CALM TO LIGHT AND VARIABLE THROUGH THE PERIOD.
OUTLOOK... WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT-SUN:
MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
ISSUED BY NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
956 AM EST WED FEB 18 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH THE REGION ALONG A COLD FRONT THIS
EVENING. BY THURSDAY, HIGH PRESSURE WILL BEGIN TO DIVE SOUTHEAST
INTO THE CENTRAL UNITED STATES REACHING THE EAST COAST ON FRIDAY.
LOW PRESSURE WILL TRACK NORTHEAST FROM THE SOUTHERN PLAINS UP THE
APPALACHIANS THIS WEEKEND. ANOTHER AREA OF ARCTIC HIGH PRESSURE
WILL DIVE SOUTHEAST TOWARD THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 14Z...SUNNY WITH ALL AREAS NOW ABOVE ZERO AND GENERALLY TEENS
TO LOW 20S. LIGHT NORTH FLOW WILL BECOME LIGHT SLY THIS AFTERNOON
AHEAD OF A COLD FRONT CURRENTLY OVER THE OHIO VALLEY. MAX TEMPS
MID 20S FOR ERN PA AND NRN NJ...LOW 30S FOR CNTRL/SRN NJ. LIGHT
FLOW/LACK OF MIXING MIGHT LIMIT TEMPS A BIT...BUT THE FULL
SUNSHINE WILL AT LEAST CAUSE MELTING OF THE SNOWPACK ACROSS THE
AREA (SEEN IN VISIBLE IMAGERY). WILL MANTAIN ABOVE AVG CONFIDENCE
FOR FCST TODAY.
SNOW SHOWERS OR FLURRIES WILL DEVELOP OVER EASTERN PA VERY LATE IN
THE DAY IN ASSOCIATION WITH LOW LEVEL CONVERGENCE AHEAD OF THE ARCTIC
COLD FRONT AND THE 500 MB PVA WITH THE APPROACHING 500MB TROUGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
BRIEF SNOW SHOWERS/WEAKENING SQUALL EXPECTED TO CROSS THE CWA THIS
EVENING. STILL ON TRACK FOR THE 1-2 INCHES IN FAR NWRN SECTIONS OF
THE CWA/POCONOS TO 0.5 TO 1 INCH ALONG THE DELAWARE RIVER/BAY TO
0.5 INCH ALONG THE SHORE.
WILL REISSUE/UPDATE SPS AT NOON.
PREVIOUS...
MODELS SUGGEST DECENT SNOW GROWTH WITH ANY OF THE MEASURABLE WATER
EQUIVALENT SNOW THAT SPREADS EWD THROUGH THE REGION. NAM MAY HAVE
A WET BIAS FOR TONIGHT BUT THERE IS LIKELY TO BE GENERAL DUSTINGS
TO SPOTTY 2-3 INCH SNOWS. 50 50 BLENDED 00Z/18 GFS/NAM MOS GUIDANCE
IS APPLIED EXCEPT I THOUGHT THE TEMPS WOULD RUN COLDER NEAR DAYBREAK
THURSDAY SO I BLENDED IN THE ECMWF 12Z THURSDAY TEMPS. LIGHT SOUTH
WIND BECOMES NW GUSTY 25 TO 30 MPH AFTER MIDNIGHT.
NO ADVY ATTM BUT AN SPS WAS ISSUED FOR EASTERN PA TO COVER THE
ONSET OF ACCUMULATIVE SLIPPERY TRAVEL SNOWS AND VERY RAPIDLY
CHANGING TRAVEL CONDITIONS. THE 10Z RAP AND 07Z HRRR HAVE IT TO
VARYING DEGREES.
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THURSDAY THROUGH FRIDAY NIGHT: THE ARCTIC FRONT WILL BE EAST OF THE
REGION WITH A FRESH SHOT OF COLD AIR COMING INTO THE REGION. LOW
TEMPERATURES FRIDAY MORNING LIKELY WILL BE AROUND 0 FOR MOST OF THE
REGION AIDED IN PART BY SNOWCOVER. DID GO A FEW DEGREES UNDER
MAV/MET TO ACCOUNT FOR THIS, THESE GUIDANCE SETS HAVE BEEN TO WARM
WITH LOW TEMPERATURES RECENTLY. WITH STRONG NORTHWEST WINDS BEHIND
THE FRONT, WIND CHILLS COULD BE AROUND -25 FRIDAY MORNING FOR THE
NORTHWEST PART OF THE CWA. A WIND CHILL WATCH HAS BEEN ISSUED FOR
THIS POSSIBILITY. WIND CHILLS WILL STILL BE DANGEROUSLY COLD ACROSS
THE ENTIRE REGION WITH PEAK VALUES FROM -15 TO -20. BE PREPARED TO
BUNDLE UP AND TAKE PLENTY OF PRECAUTIONS IF YOU HAVE TO BE OUT
LATE THURSDAY INTO FRIDAY. IN TERMS OF GUSTS, THE GFS IS A LITTLE
MORE ROBUST THAN THE NAM. THIS FORECAST TOOK A MIDDLE GROUND
APPROACH BETWEEN BUFKIT ANALYSIS FROM BOTH MODELS WHICH SHOW GUSTS
UP TO AND AROUND 30 MPH. STEEP LAPSE RATES MAY LEAD TO SOME PATCHY
FLURRIES ON THURSDAY.
SATURDAY AND SUNDAY: MODEL GUIDANCE HAS COME TO CONSENSUS THAT LOW
PRESSURE WILL FORM OVER THE SOUTHERN PLAINS AND HEAD NORTHEAST UP
THE APPALACHIANS BETWEEN TWO HIGH PRESSURE SYSTEMS. THE LACK OF A FIRM
HIGH PRESSURE SOURCE TO OUR NORTH MAKES THIS CUTTER TRACK POSSIBLE.
OVERRUNNING CLOUDS AND LIGHT PRECIPITATION IN ADVANCE OF A WARM FRONT WILL
MOVE NORTH SATURDAY WITH THE HIGHEST CHANCES OF PRECIPITATION FROM
LATE SATURDAY NIGHT THROUGH SUNDAY. A MIXTURE OF SNOW, ICE AND RAIN
IS LIKELY TO DEVELOP QUICKLY CHANGING TO RAIN ACROSS MOST OF THE
REGION, PERHAPS STAYING A MIX LONGER INTO SUNDAY ACROSS THE POCONOS.
PERIODS OF RAIN MAY THEN END AS SOME SNOW ON THE BACKEND, MOST
LIKELY FLURRIES BY SUNDAY NIGHT. A NON-DIURNAL TEMPERATURE TREND WAS
USED WITH THE CONSENSUS THAT TEMPERATURES RISE SATURDAY NIGHT FROM
AROUND 30 INTO THE 40`S ON SUNDAY. THE GFS IS WARMER THAN THE
CURRENT FORECAST BUT GIVEN A DECENT SNOWCOVER IN PLACE, STILL THINK
LOW LEVEL COLD AIR CAN PUT SOME FIGHT. SOME LIGHT ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE WITH THE HIGHEST ACCUMULATIONS WELL NORTH
AND WEST OF OUR REGION. ALSO, DID TREND HIGHER THAN ENSEMBLE
GUIDANCE ON THE WINDS AS WELL.
MONDAY AND TUESDAY: ANOTHER COLD FRONT MOVES THROUGH MONDAY MORNING.
THIS COLD SHOT DOES NOT LOOK AS IMPRESSIVE AS THE PAST FEW BUT DID
TREND TEMPERATURES A FEW DEGREES COOLER THAN THE ENSEMBLE GUIDANCE.
FOR NOW, WILL JUST CARY A LINGERING CHANCE FOR SOME LIGHT SNOW ACROSS
THE REGION WITH THE ECMWF BEING SLOWER TO CLEAR THE FRONTAL BOUNDARY.
THERE IS POTENTIAL FOR ANOTHER WAVE OF LOW PRESSURE TO FORM ALONG
THE BOUNDARY TO OUR SOUTH AS SHOWN ON THE CMC MODEL AND TO SOME
EXTENT THE ECMWF BY THE END OF THE PERIOD. FOR NOW, WILL LEAVE OUT
OF FORECAST.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR/SUNNY THIS MORNING. SCT CLOUDS AOA 15000 FT WITH SCT
CLOUDS NEAR 4000 FT MOVING IN FROM THE WEST THIS AFTN. THEN CIGS
NEAR 4000 FT ARRIVE LATE IN THE DAY OR EVENING. LIGHT WIND.
CONFIDENCE: ABOVE AVERAGE.
TONIGHT... VFR CIGS NEAR 4000 FT WITH BRIEF PERIODS OF IFR OR MVFR
CONDS IN SNOW SHOWERS FOR A 6 HOUR PERIOD MAINLY BETWEEN 00Z AND 06Z/19
BECOMING VFR SCT CLOUDS AOA 4000 FT TOWARD 09Z THURSDAY MORNING.
SNOWFALL FROM A DUSTING THAT COULD BE BLOWN OFF MOST PAVEMENTS BY
THE WEST NORTHWEST WIND GUSTS TO 25-30 KT THAT DEVELOPS AFTER
05Z/19, BUT SOME AMOUNTS RANGING UP TO 1-2 INCHES...POSSIBLY KRDG
TO KMPO. CONFIDENCE: AVERAGE.
OUTLOOK...
THURSDAY: VFR, NORTHWEST WIND GUSTS UP TO 30 KNOTS.
THURSDAY NIGHT THROUGH FRIDAY NIGHT: VFR.
SATURDAY AND SATURDAY NIGHT: CONDITIONS DETERIORATING TO MVFR/IFR
SATURDAY NIGHT WITH A MIX OF RAIN, SNOW AND FREEZING RAIN CHANGING
TO RAIN.
SUNDAY: VFR AND IFR IN RAIN.
&&
.MARINE...
**SINCE MUCH OF DELAWARE BAY IS COVERED BY ICE WE BEGIN ADDING
PHRASING "ON ICE FREE WATERS" FOR THE FIRST FOUR PERIODS OF THE
FORECAST**
TODAY...SCA HAZ SEAS FOR ALL THE ATLC WATERS UNTIL 5 PM EST. THIS
SWELL IS A RESULT OF YESTERDAYS STORM. FOR THE BAY SUB SCA
CONDITIONS CONTINUE TODAY IN A LIGHT WIND REGIME.
TONIGHT...GLW STARTS AT MIDNIGHT FOR DELAWARE BAY AND ANZ453-55.
REMAINING GALE FOR OTHER NNJ WATERS BEGINS 10 AM THURSDAY. THE
GALE IS A LOW ENDER .. MOSTLY 34-40 KT GUSTS.
OUTLOOK...
THURSDAY AND FRIDAY: NORTHWEST WIND GUSTS AROUND 35 KNOTS THROUGHOUT
MOST OF THIS PERIOD, DIMINISHING SOME FRIDAY AFTERNOON. FREEZING
SPRAY SOME MODERATE TO HEAVY IN ICE FREE AREAS. GALE WARNING.
LOW WATER AT LOW TIDES MAY BE A SERIOUS MARINE NAVIGATION HAZARD.
FRIDAY NIGHT AND SATURDAY: SUB SCA SEAS AND WINDS.
SATURDAY NIGHT AND SUNDAY: SEAS BUILDING TO SCA CRITERIA, SOUTHERLY
SCA GUSTS.
&&
.CLIMATE...
RECORD LOW TEMPERATURES ARE ANTICIPATED THIS THURSDAY AND OR FRIDAY
MORNING WHEN WE NOW THINK THE COLDEST DAYS OF THE WINTER SHOULD
OCCUR. THIS BECAUSE MINUS 25C 850 MB AIR IS MORE MODELED TO
OVERSPREAD MORE OF OUR AREA AND SIT HERE FOR 12 HOURS. EVEN
SATURDAY MAY HAVE RECORD COLD NEAR MIDNIGHT BEFORE TEMPS START
RISING AHEAD OF THE NEXT ARCTIC COLD FRONT.
WE`RE TALKING THE COLDEST AT PHILADELPHIA SINCE JAN 19, 1994 WHEN
IT WAS 5 BELOW. IT WILL PROBABLY BE EASIER TO GET BELOW ZERO LATE
THIS WEEK DUE TO THE SOUTHWARD SNOW COVER INCREASE.
ADDITIONALLY FOR THE URBAN CENTERS AND THAT WILL FOCUS ON PHL...IF
THE LOW IS ZERO OR COLDER THIS WILL BE COLDEST LOW TEMPERATURE
AT PHL - SO LATE IN THE SEASON!
THOSE RECORDS LISTED BELOW...
(POR = PERIOD OF RECORD BEGINS)
POR 2/19 2/20 2/21
1874 KACY 4-1903 0-1966 3-1968
1872 KPHL 3-1903 1-1979 6-1968
1894 KILG 2-1936 5-1978 6 1968 AND 1934
1922 KABE 0-1936 -2 1936 0-1936
1865 KTTN 2 1903,1936 6 -1936 6-1893
1948 KGED 11-1993 0-1979 8-1959
1869 KRDG - 2 1903 -3 1903 -2 1978,1903
1901 KMPO -10 1903 -18 1993 -8 1993
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR PAZ054-055-060>062.
WIND CHILL ADVISORY FROM 4 AM TO 7 PM EST THURSDAY FOR PAZ054-
055.
NJ...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR NJZ001-007.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 10 AM THURSDAY TO 1 PM EST FRIDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS
AFTERNOON FOR ANZ450>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST FRIDAY FOR
ANZ453>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST FRIDAY FOR
ANZ430-431.
&&
$$
UPDATE...JACKSON
PREVIOUS...DRAG/GAINES/658
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
658 AM EST WED FEB 18 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK THROUGH THE REGION ALONG A COLD FRONT TODAY.
BY THURSDAY, HIGH PRESSURE WILL BEGIN TO DIVE SOUTHEAST INTO THE CENTRAL
UNITED STATES REACHING THE EAST COAST ON FRIDAY. LOW PRESSURE WILL
TRACK NORTHEAST FROM THE SOUTHERN PLAINS UP THE APPALACHIANS THIS
WEEKEND. ANOTHER AREA OF ARCTIC HIGH PRESSURE WILL DIVE SOUTHEAST
TOWARD THE REGION BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
**THE STERLING OFFICE WILL BE BACKING US UP BEGINNING 8 AM TODAY AS WE
SHIFT FROM AWIPS 1 TO AWIPS2**
WE PRESUME WE WILL BE UP AND RUNNING SOMETIME LATE THIS EVENING.
TODAY...NICE AND SUNNY. STILL A LITTLE COLD BUT INCREASING SUN
ANGLE ALREADY MELTING SNOWS. LIGHT WIND THROUGH EARLY AFTERNOON.
50 50 BLENDED 00Z/18 GFS/NAM MOS GUIDANCE EXCEPT FCST THE WARMER
00Z/18 NAM MOS. MY CONCERN...LIGHT WIND AND LACK OF MIXING MIGHT
PREVENT REACHING THE FCST VALUES. FOR NOW THOUGH: ABOVE AVG
CONFIDENCE IN THIS PART OF THE FCST.
SNOW SHOWERS OR FLURRIES WILL DEVELOP OVER EASTERN PA VERY LATE IN
THE DAY IN ASSOCIATION WITH LOW LEVEL CONVERGENCE AHEAD OF THE ARCTIC
COLD FRONT AND THE 500 MB PVA WITH THE APPROACHING 500MB TROUGH.
06Z NAM AND GFS REVIEWED. NO CHANGE IN PHILOSOPHY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
MODELS SUGGEST DECENT SNOW GROWTH WITH ANY OF THE MEASURABLE WATER
EQUIVALENT SNOW THAT SPREADS EWD THROUGH THE REGION. NAM MAY HAVE
A WET BIAS FOR TONIGHT BUT THERE IS LIKELY TO BE GENERAL DUSTINGS
TO SPOTTY 2-3 INCH SNOWS. 50 50 BLENDED 00Z/18 GFS/NAM MOS GUIDANCE
IS APPLIED EXCEPT I THOUGHT THE TEMPS WOULD RUN COLDER NEAR DAYBREAK
THURSDAY SO I BLENDED IN THE ECMWF 12Z THURSDAY TEMPS. LIGHT SOUTH
WIND BECOMES NW GUSTY 25 TO 30 MPH AFTER MIDNIGHT.
NO ADVY ATTM BUT AN SPS WAS ISSUED FOR EASTERN PA TO COVER THE
ONSET OF ACCUMULATIVE SLIPPERY TRAVEL SNOWS AND VERY RAPIDLY
CHANGING TRAVEL CONDITIONS. THE 10Z RAP AND 07Z HRRR HAVE IT TO
VARYING DEGREES.
CONFIDENCE: ABOVE AVERAGE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THURSDAY THROUGH FRIDAY NIGHT: THE ARCTIC FRONT WILL BE EAST OF THE
REGION WITH A FRESH SHOT OF COLD AIR COMING INTO THE REGION. LOW
TEMPERATURES FRIDAY MORNING LIKELY WILL BE AROUND 0 FOR MOST OF THE
REGION AIDED IN PART BY SNOWCOVER. DID GO A FEW DEGREES UNDER
MAV/MET TO ACCOUNT FOR THIS, THESE GUIDANCE SETS HAVE BEEN TO WARM
WITH LOW TEMPERATURES RECENTLY. WITH STRONG NORTHWEST WINDS BEHIND
THE FRONT, WIND CHILLS COULD BE AROUND -25 FRIDAY MORNING FOR THE
NORTHWEST PART OF THE CWA. A WIND CHILL WATCH HAS BEEN ISSUED FOR
THIS POSSIBILITY. WIND CHILLS WILL STILL BE DANGEROUSLY COLD ACROSS
THE ENTIRE REGION WITH PEAK VALUES FROM -15 TO -20. BE PREPARED TO
BUNDLE UP AND TAKE PLENTY OF PRECAUTIONS IF YOU HAVE TO BE OUT
LATE THURSDAY INTO FRIDAY. IN TERMS OF GUSTS, THE GFS IS A LITTLE
MORE ROBUST THAN THE NAM. THIS FORECAST TOOK A MIDDLE GROUND
APPROACH BETWEEN BUFKIT ANALYSIS FROM BOTH MODELS WHICH SHOW GUSTS
UP TO AND AROUND 30 MPH. STEEP LAPSE RATES MAY LEAD TO SOME PATCHY
FLURRIES ON THURSDAY.
SATURDAY AND SUNDAY: MODEL GUIDANCE HAS COME TO CONSENSUS THAT LOW
PRESSURE WILL FORM OVER THE SOUTHERN PLAINS AND HEAD NORTHEAST UP
THE APPALACHIANS BETWEEN TWO HIGH PRESSURE SYSTEMS. THE LACK OF A FIRM
HIGH PRESSURE SOURCE TO OUR NORTH MAKES THIS CUTTER TRACK POSSIBLE.
OVERRUNNING CLOUDS AND LIGHT PRECIPITATION IN ADVANCE OF A WARM FRONT WILL
MOVE NORTH SATURDAY WITH THE HIGHEST CHANCES OF PRECIPITATION FROM
LATE SATURDAY NIGHT THROUGH SUNDAY. A MIXTURE OF SNOW, ICE AND RAIN
IS LIKELY TO DEVELOP QUICKLY CHANGING TO RAIN ACROSS MOST OF THE
REGION, PERHAPS STAYING A MIX LONGER INTO SUNDAY ACROSS THE POCONOS.
PERIODS OF RAIN MAY THEN END AS SOME SNOW ON THE BACKEND, MOST
LIKELY FLURRIES BY SUNDAY NIGHT. A NON-DIURNAL TEMPERATURE TREND WAS
USED WITH THE CONSENSUS THAT TEMPERATURES RISE SATURDAY NIGHT FROM
AROUND 30 INTO THE 40`S ON SUNDAY. THE GFS IS WARMER THAN THE
CURRENT FORECAST BUT GIVEN A DECENT SNOWCOVER IN PLACE, STILL THINK
LOW LEVEL COLD AIR CAN PUT SOME FIGHT. SOME LIGHT ICE AND SNOW
ACCUMULATIONS ARE POSSIBLE WITH THE HIGHEST ACCUMULATIONS WELL NORTH
AND WEST OF OUR REGION. ALSO, DID TREND HIGHER THAN ENSEMBLE
GUIDANCE ON THE WINDS AS WELL.
MONDAY AND TUESDAY: ANOTHER COLD FRONT MOVES THROUGH MONDAY MORNING.
THIS COLD SHOT DOES NOT LOOK AS IMPRESSIVE AS THE PAST FEW BUT DID
TREND TEMPERATURES A FEW DEGREES COOLER THAN THE ENSEMBLE GUIDANCE.
FOR NOW, WILL JUST CARY A LINGERING CHANCE FOR SOME LIGHT SNOW ACROSS
THE REGION WITH THE ECMWF BEING SLOWER TO CLEAR THE FRONTAL BOUNDARY.
THERE IS POTENTIAL FOR ANOTHER WAVE OF LOW PRESSURE TO FORM ALONG
THE BOUNDARY TO OUR SOUTH AS SHOWN ON THE CMC MODEL AND TO SOME
EXTENT THE ECMWF BY THE END OF THE PERIOD. FOR NOW, WILL LEAVE OUT
OF FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR SCT CLOUDS AOA 15000 FT WITH SCT CLOUDS NEAR 4000 FT
DEVELOPING MIDDAY OR AFTN. THEN CIGS NEAR 4000 FT ARRIVE LATE IN
THE DAY OR EVENING. LIGHT WIND. CONFIDENCE: ABOVE AVERAGE.
TONIGHT... VFR CIGS NEAR 4000 FT WITH BRIEF PERIODS OF IFR OR MVFR
CONDS IN SNOW SHOWERS FOR A 6 HOUR PERIOD MAINLY BETWEEN 00Z AND 06Z/19
BECOMING VFR SCT CLOUDS AOA 4000 FT TOWARD 09Z THURSDAY MORNING.
SNOWFALL FROM A DUSTING THAT COULD BE BLOWN OFF MOST PAVEMENTS BY
THE WEST NORTHWEST WIND GUSTS TO 25-30 KT THAT DEVELOPS AFTER
05Z/19, BUT SOME AMOUNTS RANGING UP TO 1-2 INCHES...POSSIBLY KRDG
TO KMPO. CONFIDENCE: AVERAGE.
OUTLOOK...
THURSDAY: VFR, NORTHWEST WIND GUSTS UP TO 30 KNOTS.
THURSDAY NIGHT THROUGH FRIDAY NIGHT: VFR.
SATURDAY AND SATURDAY NIGHT: CONDITIONS DETERIORATING TO MVFR/IFR
SATURDAY NIGHT WITH A MIX OF RAIN, SNOW AND FREEZING RAIN CHANGING
TO RAIN.
SUNDAY: VFR AND IFR IN RAIN.
&&
.MARINE...
**SINCE MUCH OF DELAWARE BAY IS COVERED BY ICE WE BEGIN ADDING
PHRASING "ON ICE FREE WATERS" FOR THE FIRST FOUR PERIODS OF THE
FORECAST**
THIS INFO BEING HAND EDITED WILL NOT TRANSFER TO THE AUTOMATED POINT
AND CLICK POINT DATA.
ALSO ADDED A PHRASE ABOUT THE ICE IN THE MWW AND THE SYNOPSIS.
TODAY...EXTENDED THE SCA HAZ SEAS FOR ALL THE ATLC WATERS THROUGH 5
PM EST. THIS SWELL IS A RESULT OF YESTERDAYS STORM. FOR THE BAY
SUB SCA CONDITIONS CONTINUE TODAY IN A LIGHT WIND REGIME.
TONIGHT...WE STARTED THE GLW AROUND 06Z FOR DELAWARE BAY AND ANZ453-55.
WE DELAYED THE REMAINING GALE WARNING CONVERSION FOR OTHER NNJ WATERS
UNTIL DAYLIGHT THURSDAY. THE GALE IS A LOW ENDER .. MOSTLY 34-40 KT
GUSTS.
OUTLOOK...
THURSDAY AND FRIDAY: NORTHWEST WIND GUSTS AROUND 35 KNOTS THROUGHOUT
MOST OF THIS PERIOD, DIMINISHING SOME FRIDAY AFTERNOON. FREEZING
SPRAY SOME MODERATE TO HEAVY IN ICE FREE AREAS. GALE WARNING.
LOW WATER AT LOW TIDES MAY BE A SERIOUS MARINE NAVIGATION HAZARD.
FRIDAY NIGHT AND SATURDAY: SUB SCA SEAS AND WINDS.
SATURDAY NIGHT AND SUNDAY: SEAS BUILDING TO SCA CRITERIA, SOUTHERLY
SCA GUSTS.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORIES WILL PROBABLY BE NEEDED FOR LOW TIDE CYCLES
THURSDAY AND FRIDAY MORNING FOR THE ATLC COASTS AND EVENTUALLY
SPS`S FOR THE TIDAL DEL RIVER FOR ALL THURSDAY AND FRIDAY LOW
WATER TIDE CYCLES - DESPITE ANY ICE LIMITATIONS TO MARINE NAVIGATION.
&&
.CLIMATE...
RECORD LOW TEMPERATURES ARE ANTICIPATED THIS THURSDAY AND OR FRIDAY
MORNING WHEN WE NOW THINK THE COLDEST DAYS OF THE WINTER SHOULD
OCCUR. THIS BECAUSE MINUS 25C 850 MB AIR IS MORE MODELED TO
OVERSPREAD MORE OF OUR AREA AND SIT HERE FOR 12 HOURS. EVEN
SATURDAY MAY HAVE RECORD COLD NEAR MIDNIGHT BEFORE TEMPS START
RISING AHEAD OF THE NEXT ARCTIC COLD FRONT.
WE`RE TALKING THE COLDEST AT PHILADELPHIA SINCE JAN 19, 1994 WHEN
IT WAS 5 BELOW. IT WILL PROBABLY BE EASIER TO GET BELOW ZERO LATE
THIS WEEK DUE TO THE SOUTHWARD SNOW COVER INCREASE.
ADDITIONALLY FOR THE URBAN CENTERS AND THAT WILL FOCUS ON PHL...IF
THE LOW IS ZERO OR COLDER THIS WILL BE COLDEST LOW TEMPERATURE
AT PHL - SO LATE IN THE SEASON!
THOSE RECORDS LISTED BELOW...
(POR = PERIOD OF RECORD BEGINS)
POR 2/19 2/20 2/21
1874 KACY 4-1903 0-1966 3-1968
1872 KPHL 3-1903 1-1979 6-1968
1894 KILG 2-1936 5-1978 6 1968 AND 1934
1922 KABE 0-1936 -2 1936 0-1936
1865 KTTN 2 1903,1936 6 -1936 6-1893
1948 AGED 11-1993 0-1979 8-1959
1869 KRDG - 2 1903 -3 1903 -2 1978,1903
1901 KMPO -10 1903 -18 1993 -8 1993
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR PAZ054-055-060>062.
WIND CHILL ADVISORY FROM 4 AM TO 7 PM EST THURSDAY FOR PAZ054-
055.
NJ...WIND CHILL WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING
FOR NJZ001-007.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING FROM 10 AM THURSDAY TO 1 PM EST FRIDAY FOR
ANZ450>452.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EST THIS
AFTERNOON FOR ANZ450>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 1 PM EST FRIDAY FOR
ANZ453>455.
GALE WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST FRIDAY FOR
ANZ430-431.
&&
$$
SYNOPSIS...GAINES
NEAR TERM...DRAG 658
SHORT TERM...DRAG
LONG TERM...GAINES
AVIATION...DRAG/GAINES 658
MARINE...DRAG/GAINES 658
TIDES/COASTAL FLOODING...658
CLIMATE...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
813 AM CST WED FEB 18 2015
.SHORT TERM...
315 AM CST
THROUGH THURSDAY...
A MASSIVE UPPER LOW/TROUGH CENTERED OVER
NORTHERN ONTARIO CONTINUES TO BE SPREAD ACROSS MOST OF NORTH
AMERICA. AN EMBEDDED SHORTWAVE IS TRACKING SOUTHEAST ACROSS SOUTHERN
WISCONSIN/NORTHERN IOWA AND WILL CROSS THE LOCAL AREA THROUGH THE
MORNING. WATER VAPOR SHOWS SHARP RIDGING OVER THE WEST COAST
EXTENDING WELL INTO THE YUKON/NUNAVUT WITH A STRAIGHT NORTH/SOUTH
TRAJECTORY DOWN THE WEST FLANK OF THE BIG TROUGH INTO THE PLAINS.
EVENING UPPER AIR ANALYSIS SHOWS H85 TEMPS OF -28C INTO NORTHERN
MINNESOTA BEHIND THE APPROACHING SHORTWAVE AND ON TRACK TO WORK INTO
THE LOCAL AREA LATER TODAY. AT THE SURFACE...A BROAD AREA OF LOW
PRESSURE STRETCHES FROM WESTERN QUEBEC SOUTHWEST TO LAKE HURON WITH
A SECONDARY LOW CIRCULATION OVER LOWER MICHIGAN. A COLD FRONT
EXTENDS SOUTHWEST FROM THE CENTRAL WISCONSIN ACROSS IOWA AND WILL
CROSS THE AREA THIS MORNING. THE LARGER SCALE ASCENT AND THE INFLUX
OF COLD AIR IS DRIVING AREAS OF LIGHT SNOW WITH SOME EMBEDDED SNOW
SHOWERS. THIS ACTIVITY WILL WORK ACROSS THE AREA THROUGH MID
MORNING. OVERALL IT WILL REMAIN LIGHT BUT DO EXPECT MORE INTENSE
RETURNS TO BE EMBEDDED WITHIN THE BROADER AREA OF LIGHT
SNOW...ESPECIALLY AFTER DAYBREAK. A FEW TENTHS OF ACCUMULATION IS
POSSIBLE WITH THE MORE PERSISTENT SHOWERS WITH AROUND A HALF INCH
NOT OUT OF THE QUESTION GIVEN THAT THE SNOW WILL BE FLUFFY BUT MANY
AREAS MAY SEE LITTLE MORE THAN A DUSTING. CONTINUED COLD
ADVECTION/CYCLONIC FLOW WILL SUPPORT FLURRIES OR SOME LIGHT SNOW
THROUGH THE REST OF THE DAY ONCE THE MAIN WAVE HAS DEPARTED. LAKE
EFFECT SNOW SHOWERS WILL BE OCCURRING EAST OF LAKE MICHIGAN AND WILL
LIKELY PERIODICALLY AFFECT PORTIONS OF PORTER COUNTY. FAR NORTHEAST
SECTIONS ARE MOST FAVORED FOR LIGHT ACCUMULATION...POSSIBLY AROUND
AN INCH.
COLD ADVECTION WILL PERSIST THROUGH THE DAY. HIGH TEMPS WILL BE A
LITTLE TRICKY GIVEN THAT THERE WILL PROBABLY BE AT LEAST SOME BREAKS
OF SUNSHINE FROM LATE MORNING THROUGH THE AFTERNOON. THE CORE OF THE
COLDEST AIR DOES NOT ARRIVE UNTIL THIS EVENING SO THERE SHOULD BE AT
LEAST SOME MODEST RECOVERY FROM MORNING TEMPS BEFORE THEY LEVEL OFF
AND PROBABLY FALL SOMEWHAT DURING THE AFTERNOON. THIS WILL PUT HIGHS
IN THE SINGLE DIGITS FOR MOST AREAS THOUGH THE SOUTHEAST THIRD OF
THE AREA MAY SEE READINGS OF 10 OR JUST ABOVE. HIGH PRESSURE WILL BE
SPREADING INTO THE MISSISSIPPI RIVER VALLEY THROUGH TONIGHT KEEPING
THE LOCAL AREA IN THE PRESSURE GRADIENT BETWEEN IT AND LOW PRESSURE
TO THE EAST. THIS WILL KEEP A STEADY NORTHWEST BREEZE IN PLACE
KEEPING TEMPS FROM RADIATING OUT BUT LOWS WILL STILL BE BITTERLY
COLD IN THE -4 TO -10 OR SO RANGE. WIND CHILLS WILL BE PUSHED TO -20
TO -30 SO WILL ISSUE A WIND CHILL ADVISORY FROM THIS EVENING THROUGH
MUCH OF THURSDAY MORNING. THE BIG UPPER TROUGH WILL SHIFT EAST
THURSDAY ALLOWING FOR SOME WARMING OF THE MID LEVELS BY LATE DAY.
THE SURFACE HIGH WILL BE OVERHEAD BY AFTERNOON SO WEAK MIXING WILL
NOT BE ABLE TO TAKE ADVANTAGE OF THE WARMING ALOFT. THIS WILL LIKELY
KEEP HIGHS IN THE MID SINGLE DIGITS BUT THE WILD CARD WILL BE THE
SUN WHICH IS QUITE STRONG AND WITH AN OLD SNOW PACK MAY BE ABLE TO
PROVIDE AN EXTRA FEW DEGREES OVER FORECAST HIGHS. REGARDLESS IT WILL
BE COLD AND 3 OF THE 4 RECORD TEMPS OUTLINED BELOW WILL BE IN
JEOPARDY THURSDAY. WINDS WILL BE MUCH LIGHTER THURSDAY NIGHT
ALLOWING FOR BETTER RADIATIONAL COOLING BUT MID/HIGH CLOUDS WILL BE
APPROACHING FROM THE WEST WHICH COULD ALLOW FOR SOME WARMING LATE.
SOME NORTHERN AREAS MAY NEED A WIND CHILL ADVISORY WITH WIND CHILLS
IN THE LOWER MINUS 20S.
MDB
&&
.LONG TERM...
315 AM CST
FRIDAY THROUGH TUESDAY...
THE UPPER FLOW WILL BE FLATTENING FRIDAY AS
THE BIG TROUGH CONTINUES EAST AND A WEAK UPPER TROUGH WORKS
SOUTHEAST INTO THE NORTHERN PLAINS. WARM ADVECTION WILL CONTINUE
ALOFT AND WITH THE SURFACE HIGH SHIFTING EAST SOUTHERLY FLOW WILL
DEVELOP AT THE SURFACE LEADING TO A MODERATION OF TEMPS. THE WARM
ADVECTION IN ADVANCE OF THE UPPER TROUGH/CLIPPER WILL BRING
INCREASED CLOUD COVER AND MAYBE SOME LIGHT SNOW SO WILL CARRY LOW
POPS FRIDAY. THINGS BECOME MORE INTERESTING AND COMPLEX FRIDAY NIGHT
AND SATURDAY AS A LARGER SCALE TROUGH DIGS INTO THE DESERT
SOUTHWEST. THIS WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS TEXAS
WITH AN INVERTED TROUGH/WARM FRONT DEVELOPING TO THE NORTHEAST. THE
SFC LOW WILL LIFT NORTHEAST COMBINING WITH AN OPEN GULF TO BRING A
GOOD PUSH OF MOISTURE NORTHEAST WITH IT. THE SIGNAL FOR THIS SYSTEM
HAS BEEN IN PLACE FOR SEVERAL DAYS BUT TRACK/STRENGTH DETAILS HAVE
BEEN INCONSISTENT. TYPICALLY A FURTHER SOUTH TRACK WOULD BE FAVORED
COMING OUT OF SUCH A STRONG ARCTIC BLAST BUT WITH THE INITIAL
TROUGH/CLIPPER AND DE-AMPLIFICATION OF THE UPPER FLOW BEFORE THE
MAIN TROUGH DRIVING THIS SYSTEM COMES INTO PLAY THE MID LEVEL
THERMAL GRADIENT WILL BE ABLE TO BE PUSHED BACK TOWARD THE AREA. IT
SEEMS THAT GUIDANCE MAY CONTINUE TO FAVOR A NORTHWARD TREND...WHICH
HAS BEEN THE TREND WITH MOST OF THESE SOUTHERN SYSTEMS THIS WINTER.
THIS WILL BE SOMETHING TO WATCH AND FOR NOW SOUTHEAST AREAS WILL BE
AT GREATEST RISK TO HAVE PRECIP FALL SO WILL CONTINUE WITH HIGHEST
POPS IN THESE AREAS. TEMP DETAILS WILL ALSO DEPEND ON THE TRACK BUT
LOWER 30S LOOK GOOD FOR NOW...WITH PRECIP TYPE POSSIBLY BECOMING AN
ISSUE.
COLDER AIR WILL SPREAD IN BEHIND THIS SYSTEM AS CANADIAN HIGH
PRESSURE ONCE AGAIN MOVES INTO THE CENTRAL U.S. SEVERAL UPPER
TROUGHS/CLIPPERS LOOK TO CROSS THE REGION EARLY NEXT WEEK CARVING
OUT ANOTHER BIG UPPER TROUGH SO THE MILDER AIR OF FRIDAY/SATURDAY
WILL BE SHORT LIVED WITH COLDER THAN NORMAL ARCTIC AIR EXPECTED TO
TAKE OVER FOR MUCH OF NEXT WEEK. IN OTHER WORDS THE CONDITIONS OF
THE RECENT FEW DAYS LOOK TO BE REPEATED TEMP AND PRECIP WISE WITH
BOUTS OF LIGHT SNOW WITH EACH PASSING WAVE.
MDB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE RECORD LOW
MAXIMUM TEMPERATURES.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE AT ALMOST ANYTIME
TODAY.
* POSSIBILITY FOR A BRIEF WINDOW OF MVFR CEILINGS THIS MORNING.
* GUSTY NORTHWEST WINDS THROUGH AFTERNOON.
RODRIGUEZ/KJB
//DISCUSSION...UPDATED 12Z...
A FEW LIGHT SNOW SHOWERS AND FLURRIES WILL IMPACT THE TERMINALS
EARLY THIS MORNING AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE
AREA. A FEW BRIEF PERIODS OF VISIBILITY RESTRICTS DOWN AROUND 2 TO 3
MILES IS POSSIBLE WITH THESE SNOW SHOWERS. HOWEVER...THIS WOULD BE
SHORT LIVED EARLY THIS MORNING. CIGS WILL ALSO LIKELY FALL DOWN
AROUND 2000 TO 2500 FEET FOR A PERIOD THIS MORNING WITH SOME OF
THESE SNOW SHOWERS. A FEW LINGERING FLURRIES ARE POSSIBLE
THEREAFTER...BUT NO REAL IMPACT IS EXPECTED. OTHERWISE...EXPECT
WINDS TO BECOME GUSTY UP TO AROUND 25 KT OUT OF THE NORTHWEST BY
LATE MORNING AND INTO THE AFTERNOON BEFORE ABATING BY EARLY
EVENING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM CONFIDENCE IN TIMING OF SNOW SHOWER ACTIVITY.
* LOW MEDIUM CONFIDENCE OF BRIEF WINDOW OF MVFR CEILINGS.
* FAIRLY HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS.
RODRIGUEZ/KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. LIGHT AND VARIABLE WINDS.
FRIDAY...CHANCE OF SN WITH IFR POSSIBLE. MODERATELY STRONG SOUTH
WINDS.
SATURDAY...CHANCE OF MVFR/IFR AND SN.
SUNDAY...MVFR CIGS POSSIBLE. SLIGHT CHANCE OF -SN EARLY.
MONDAY...PRIMARILY VFR.
TUESDAY...SLIGHT CHANCE OF SNOW SHOWERS WITH MVFR TO IFR
POSSIBLE.
KJB
&&
.MARINE...
117 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS IS STILL EXPECTED TO DEVELOP
ACROSS THE LAKE TODAY INTO TONIGHT. THE SURFACE PRESSURE GRADIENT
WILL TIGHTEN IN THE WAKE OF A SURFACE LOW...CURRENTLY SHIFTING
EASTWARD OVER THE UPPER GREAT LAKES REGION...AND AHEAD OF AN
ARCTIC SURFACE HIGH SHIFTING OVER THE NORTHERN PLAINS. IT APPEARS
THESE STRONG NORTHWEST WINDS WILL RANGE BETWEEN 30 KT AND SOME LOW
END 35 KT GALES...ESPECIALLY ACROSS THE SOUTHERN HALF OF LAKE
MICHIGAN. THE CURRENT HEADLINES FOR GALES AND FREEZING SPRAY
APPEAR TO BE ON TARGET...SO NO CHANGES ARE PLANNED AT THIS TIME.
HOWEVER...WE WILL NEED TO WATCH FOR THE POSSIBILITY OF A TIME
EXTENSION OF THE GALE/FREEZING SPRAY HEADLINE THROUGH THE NIGHT
TONIGHT...AS FORECAST GUIDANCE SUGGESTS THAT THE WINDS COULD
REMAIN ELEVATED THROUGH EARLY THURSDAY MORNING AS THE COLD ARCTIC
AIR MASS CONTINUES TO FILTER OVER THE LAKE.
WINDS WILL EASE FOR A PERIOD LATER THURSDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE BEGINS TO SHIFT OVER THE WESTERN LAKES REGION.
HOWEVER...IT APPEARS THAT WINDS WILL QUICKLY PICK UP OUT OF THE
SOUTH BY FRIDAY AS ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN
CANADA. THIS LOOKS TO RESULT IN 30 KT SOUTHERLY WINDS AND MORE
FREEZING SPRAY LAKE-WIDE ON FRIDAY.
ANOTHER STORM SYSTEM LOOKS TO DEVELOP AND SHIFT SOUTH OF THE LAKE ON
SUNDAY. DEPENDING ON THE ACTUAL STRENGTHEN OF THIS SYSTEM...IT COULD
RESULT IN A PERIOD OF STRONG NORTHERLY WINDS DOWN THE LAKE.
HOWEVER...UNCERTAINTY IS STILL SOMEWHAT HIGH WITH THIS SYSTEM.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO NOON
THURSDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO NOON THURSDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM
WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO BURNS HARBOR UNTIL
9 AM THURSDAY.
GALE WARNING...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 6 PM WEDNESDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
605 AM CST Wed Feb 18 2015
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 600 AM CST WED FEB 18 2015
Shortwave energy aloft will keep clouds/flurries around today.
Cloud heights are generally low VFR, with MVFR clouds and brief
MVFR visibility in light snow around BMI and CMI. HRRR guidance
points toward a lowering of clouds heights in general this
afternoon, with 1500-2500 FT in most areas and scattered flurries.
The bulk of the upper energy should depart to the east by this
evening, leaving clearing skies later tonight.
Northwest winds will increase this morning into the 14-18kt range,
with gusts to 30kt at times today. The strong winds will cause
blowing and drifting of the fluffy snow that fell last night,
creating slippery travel surfaces today. Wind gusts will diminish
tonight as the pressure gradient weakens, but sustained winds will
remain in the 10-15kt range through the evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS DES MOINES IA
542 AM CST WED FEB 18 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY
BEFORE GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO
THE REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM
-18C TO -23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY
COLDER. ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING
WITH THE NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE
NORTHEAST NEAR OR SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO
NOT EXPECT MUCH OF A WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF
FOR MAX TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY.
THIS RESULTED IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND
LITTLE CHANGE ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO
REACH WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/12Z
ISSUED AT 526 AM CST WED FEB 18 2015
STRONG CAA WILL CONTINUE THROUGH THE AFTERNOON. HAVE VFR CIGS/VIS
MENTIONED DURING ENTIRE TAF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-
CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-EMMET-
FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-
UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1046 AM EST Wed Feb 18 2015
...Forecast Update...
Issued at 1045 AM EST Wed Feb 18 2015
NW-SE oriented snow squalls continue to move through central and
east-central KY this morning. These squalls are moving off to the
east at 25-30 MPH and will affect the Bluegrass region of central KY
for the remainder of the morning.
Latest runs from the HRRR suggest that more NW-SE oriented finger
bands of snow squalls are expected to redevelop across the region.
Based on the last few runs of the HRRR, it appears that the best
coverage of snow showers/squalls would generally be along and east
of the I-65 corridor. Based on those trends, have increased PoPs and
cloud cover east of I-65 for the afternoon hours. While we will be
running high chance PoPs, it really is more based on expected
coverage. Some areas will see snow showers, others may escape with
only flurries. Within these squalls an additional 1 to perhaps as
much as 2 inches could be seen...especially if a band sets up over a
particular area.
We will keep the Winter Weather Advisory going through the afternoon
for the entire area. Temperatures will continue to fall with
readings mainly in the teens with a fall into single digits by the
evening. With the loss of heating and the trough axis aloft heading
to the east, we expect to see the snow shower/squall activity drop
off rapidly after sunset.
Based on upstream observations, it appears we will go more clear
tonight resulting in temperatures falling well below zero
overnight. Current thinking is that our current forecast minimums
are too warm and that further downward adjustments will be needed.
We will continue to look at the full 12Z guidance before making
major adjustments. In addition, current wind forecasts combined
with colder temperatures may necessitate an upgrade of the wind
chill advisory to a wind chill warning. Will be collaborating with
surrounding offices on this during the afternoon.
Update issued at 938 AM EST Wed Feb 18 2015
Pretty decent snow squall moving eastward through the central part
of the forecast area. The squall is just west of US 27/127 and will
continue to move east at 25-30 MPH. The squall is producing heavy
snow, winds up to 25-30 MPH and reducing visibilities down below 1/4
of a mile. This will impact the Frankfort and Lexington areas in
the next hour. One half to one inch of snowfall is expected with
this squall. Although, it is very difficult to measure the exact
snowfall as the 25-30 MPH winds are really whipping the snow around.
Update issued at 819 AM EST Wed Feb 18 2015
Surface cold front is currently pushing through the I-65 corridor at
the moment and will continue eastward toward the I-75 corridor this
morning. Current tracking suggests that it will clear our forecast
area by 16-17Z. A few snow showers will trail behind the cold
front, but the bulk of snow will still occur out ahead of the front.
Northwest winds of 15-20 MPH with gusts up to 25 MPH will be common
as we continue into the morning hours. We will see a brief lull in
the snow shower activity, but we expect snow showers and heavier
snow squalls to redevelop this afternoon. These squalls will have
the potential to lay down some additional localized accumulations.
Temperatures will continue to fall through the afternoon, so the
warmest temperatures of the day have already occurred.
.SHORT TERM (Now through Thursday)...
Issued at 318 AM EST Wed Feb 18 2015
...Bitter cold temperatures and wind chills...
An area of light to moderate snow will cross the region early this
morning, exiting to the east by late morning. Accumulations around
an inch to as much as 2 inches still look reasonable, so will keep
the Winter Weather Advisory going.
A cold front crossing the area early this morning will usher in
gusty west winds and very cold air. Winds of 10 to 20 mph will gust
to 20 to 30 mph. The CAA behind the front will cause temperatures
to fall this afternoon. The combination of very cold temperatures
and brisk winds will lead to wind chills at or below -10 by mid
afternoon, so will hoist a Wind Chill Advisory.
This afternoon we`ll have strong cold air advection aloft and partly
to mostly cloudy skies, leading to weak instability. We`ll have
high RH below 700 hPa, much of it in temperatures very conducive to
snowflake growth. Also, we`ll be beneath upper level cyclonic flow
and SPC`s snow squall parameter is expected to be around 3, which is
very supportive of snow showers. As a result, scattered snow
showers are expected throughout the area this afternoon, and could
put down additional local accumulations. In addition to the snow
showers, those biting winds on top of the new fluffy snow from this
morning (plus the pre-existing snow pack from Monday) will lead to
blowing snow, especially in rural areas. As a result, will keep the
Winter Weather Advisory going through the afternoon for the
combination of falling snow, blowing snow, and dangerous wind chills.
Any snow showers this afternoon should end quickly this evening as
the sun sets and the upper trof axis is well east of here.
With the deep snowpack in place, reinforced by new snow this morning
and possibly this afternoon, temperatures tonight will be extremely
cold. Kept the forecast we`ve had going for the past few days, and,
after seeing some of the amazing numbers on the Kentucky Mesonet for
yesterday morning`s lows, ran a tool we have that takes local cold
spots into account when determining the low temperature forecast.
The tool gave lows as low as -20 in a few locations for Thursday
morning. Decided to temper the numbers just a bit, keeping them in
the -9 to -17 range (there may be scattered clouds in the area, plus
some wind), but suffice to say that it will be a cold night. Winds
near 10 mph will continue to give us extremely cold wind chills,
possibly meeting warning criteria. If widespread warning criteria
look likely, the Wind Chill Advisory may need to be upgraded.
Tomorrow the arctic high that is giving us all this cold air will
move right into the Ohio Valley. For now we will aim for highs in
the single digits, though some locations...especially those in the
Blue Grass that have the deepest snow cover...may be lucky to get
above zero. West winds of 10 to 15 mph will continue to provide
advisory level wind chills...possibly warning level in the morning.
For the past couple of days the GFS has been advertising slightly
deeper moisture than most other models Thursday afternoon, and has
been consistent in generating some extremely light QPF. As a nod to
the model`s insistence, will add in some scattered flurries Thursday
afternoon over the Blue Grass. It doesn`t take much to squeeze a
few snowflakes out of air this cold.
For now, will allow the Wind Chill Advisory to expire Thursday
evening since winds Thursday night go nearly calm. Nevertheless,
even a tiny breeze will result in very cold wind chills in this
frigid air. Future shifts will continue to assess if an advisory
will be needed for Thursday night into Friday.
Thanks to IND, JKL, and ILN for coord.
.LONG TERM (Thursday night through Tuesday)...
Issued at 300 AM EST Wed Feb 18 2015
...Record Cold Friday Morning Then Potential Weekend Wintry Mess...
Thursday night is shaping up to be the second consecutive night of
record cold for central Kentucky and southern Indiana as a very
anomalous Arctic airmass takes over the Ohio Valley. Synoptically,
the deep upper trough will be anchored over the Great Lakes and
Northeast US while the Arctic high advances from the central Plains
eastward, centering itself over eastern Kentucky by 12z Friday
morning. 850 mb temperatures are expected to be in the -22 to -25C
range, which would be a record for ILN upper air sounding
climatology. NAEFS standardized anomalies consistently show -4 to
-5SD from Wed 18z to Fri 18z, an impressive 48 hour stretch. Helping
to reach these extreme temperatures will be the recent snowpack and
lighter winds and overall mostly clear skies. However, high level
clouds are likely to spread east across the area after midnight,
which could limit the radiational cooling, especially west of I-65.
Overall though, confidence is high that we`ll see lows -10 to -15F
with isolated -20F readings not out of the question for the rural,
typical cold spots of central/eastern Kentucky. Given these extreme
low temperatures, although winds are expected to be less than 10
mph, even light winds will create dangerous wind chills of -20 to
-25 overnight into Friday morning.
Weekend Storm System:
A wintry mix mess is looking likely for much of the region beginning
Friday late afternoon through Saturday. The upper level pattern will
transition to zonal to slightly southwesterly as a western CONUS
trough digs. Pieces of energy will eject out into the southern
Plains resulting in a surface low developing across northern Texas
by Friday evening.
Increasing moist southerly flow ahead of the surface low and
increasing isentropic lift should lead to precipitation breaking out
across Tennessee and southern Kentucky as early as mid afternoon.
Thermal profiles suggest this would be all snow and could produce
quick minor accumulations Friday late afternoon, possibly during the
afternoon commute for areas along the KY/TN border.
During the evening hours, the surface low begins to intensify and
lift toward the region. Precipitation will increase and spread
northward. A low-level jet between 700 and 900 mb will bring a warm
nose of air northward during the evening hours, expected to reach
north central Kentucky by late evening or early overnight. Right now
soundings show this warm layer being on the order of +1 to +3C
during the overnight hours, then steadily increasing Saturday
morning. North of the KY parkways, precipitation could remain as
snow for several hours before mixing with sleet then going over to a
period of freezing rain early Saturday morning. After sunrise
Saturday, most of the area is expected to be near to slightly above
freezing. The exception is across southern Indiana where
temperatures may remain cold enough to support more of a wintry mix
during the morning hours Saturday.
Saturday afternoon through Saturday night the surface low tracks
through Kentucky and precipitation is expected to continue as mainly
rain as the low levels should be sufficiently warm. Precipitation
begins to exit late Saturday night or Sunday morning, which could be
a rain/snow to snow changeover as colder air wraps behind the
system.
Model Preferences / Trends:
A time-trend analysis has shown slight warming in the thermal
profiles over the last 4 cycles, though nothing too significant at
this point. Additionally, the models seem to be a bit more amplified
and slower compared to the past runs. It is noted that the GEM was a
fast outlier while the GFS was similarly on the slower side of the
spread. The forecast was weighted toward the 18.00z ECMWF which
seems to be a good compromise at this point given the large model
spread in timing. The 18.00z guidance as a whole trended back toward
a stronger surface system, which would likely bring warmer air
northward into the region. Overall, confidence in storm track and
timing is average.
Sensible Weather and Impacts:
Overall, a wintry mess is looking more likely across the area Friday
afternoon through Saturday afternoon. The initial snow could
accumulate around 2 inches across the area before changing over to a
wintry mix of sleet and freezing rain. We`ll have to watch for ice
accumulations across southern into central Kentucky where it could
total up to 0.1", causing additional impacts. If the low level
temperatures end up colder or climb slower than forecast, then there
would be a longer period of freezing rain. Something to watch. Then
finally we`ll deal with the liquid part of the event, which is
expected to be on the order of 0.5" or more. On top of a frozen
ground and new snow/sleet/freezing rain, this may cause some
localized hydrology issues for area creeks and streams.
Finally, despite surface temperatures warming above freezing
Saturday, road temperatures will be much slower to respond given the
recent cold snap this week. This could result in additional icy and
slick roadways, or at least further into the day Saturday.
Sunday - Tuesday:
In the wake of the weekend system, a reinforcing shot of Arctic air
is advertised by the 18.00z deterministic and ensemble guidance.
This supports a continuation of below normal temperatures with
northwest flow aloft. A model consensus of highs in the upper 20s to
mid 30s and overnight lows in the teens looks reasonable at this
time.
&&
.AVIATION (12Z TAF Update)...
Issued at 630 AM EST Wed Feb 18 2015
An area of light to moderate snow will cross the terminals during
the first few hours of the TAF period. These snows will bring MVFR
ceilings and visibilities.
A cold front is crossing central Kentucky at the time of this
writing and will take winds from southwest to west, with gusts to
around 20 knots this morning. We should get a break from the snow
for a few hours during the mid to late morning hours.
This afternoon scattered snow showers will develop. The showers
should be spaced out enough to stick with VCSH in the TAFs for now.
More definitive cig/vsby can be ascertained closer to the time the
showers begin to form. Individual showers will reduce ceilings and
visibilities, but only briefly. West winds will continue, and will
gust to around 25 knots.
This evening skies will become partly cloudy and winds will relax
but continue to come in from the west as a long ridge of high
pressure builds into the Mississippi Valley.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
IN...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR INZ076>079-083-084-089>092.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR INZ076>079-083-084-089>092.
&&
$$
Update.........MJ
Short Term.....13
Long Term......ZBT
Aviation.......13
AREA FORECAST DISCUSSION
NWS RALEIGH NC
955 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY COLD
TEMPERATURES. &&
.NEAR TERM /TODAY/...
AS OF 955 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE WILL BE ALLOWED TO EXPIRE
AT 1000 AM...
...A SPECIAL WEATHER STATEMENT WILL BE ISSUED AS CAUTION ON AREA
ROADS IS STILL ADVISED...
THE TEMPERATURES WERE RISING WITH THE MORNING SUNSHINE AND MOST
AREAS WILL BE ABOVE FREEZING BETWEEN 1100 AM AND NOON. WE WILL ALLOW
THE WINTER WEATHER ADVISORY TO EXPIRE. HOWEVER... EXTREME CAUTION IS
STILL ADVISED THROUGHOUT THE DAY WITH THE MELTING PROCESS ADDING TO
THE SLIPPERINESS.
THEN... EXPECT A QUICK INCREASE IN CLOUDINESS IN THE WESTERN
PIEDMONT BY EARLY AFTERNOON. THE CLIPPER FRONT AND ASSOCIATED
VORTICITY MAX NOW CROSSING THE TN VALLEY AND MIDSOUTH WILL SHIFT
ACROSS THE APPALACHIANS BY EARLY AFTERNOON... THEN OUT OVER THE
PIEDMONT DURING THE MID TO LATE AFTERNOON.
A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD OF AND WITH THE
FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF 7-8 C/KM...
SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND BUFR SOUNDINGS
SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP THROUGH THE -
20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME... EXPECT A BRIEF
WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE ACROSS THE NORTH
HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW SHOWER MIX ACROSS THE
SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE FREEZING FOR MUCH OF
THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH TAPERING TO SLIGHT
CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT GIVEN THE FAST
MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING A CONVECTIVE
CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER RATES... AND
WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF INCH OF SNOW
IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE MID 30S NORTH
TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY
FOR NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$ SYNOPSIS...BADGETT/HARTFIELD
NEAR TERM...BADGETT/HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
640 AM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH FRIDAY... BRINGING NEAR RECORD LOW TEMPERATURES
AND VERY LOW WIND CHILLS. ANOTHER STORM SYSTEM WILL APPROACH FROM
THE WEST EARLY SATURDAY.
&&
.NEAR TERM /TODAY/...
AS OF 305 AM WEDNESDAY...
...WINTER WEATHER ADVISORY FOR BLACK ICE REMAINS IN EFFECT THROUGH
10 AM THIS MORNING...
LOTS TO CONCERN OURSELVES WITH OVER THE NEXT 48 HOURS... AND BEYOND.
FIRST... AS EARLIER INDICATED BY THE HRRR AND OTHER GUIDANCE... AN
AREA OF FREEZING FOG HAS FORMED OVER THE FAR SE PIEDMONT AND INTO
THE SANDHILLS... WHERE DEWPOINTS REMAIN ELEVATED WITH CALM AIR IN
PLACE. BASED ON THE LIMITED COVERAGE AREA AND BORDERLINE
VISIBILITIES... WILL CONTINUE TO ADDRESS THIS WITH SPECIAL WEATHER
STATEMENTS AND MONITOR THE FOG... WHICH THE HRRR SHOWS HOLDING AS A
SMALL AREA WHICH DRIFTS EAST THROUGH SUNRISE. SECOND... LINGERING
WET ROADS FROM LAST NIGHT`S WINTRY WEATHER HAS REFROZEN INTO AREAS
OF BLACK ICE... DESPITE SOME SUBLIMATION ESPECIALLY IN THE NW CWA
WHERE DEWPOINTS ARE FALLING EARLY THIS MORNING. WILL LEAVE THE
WINTER WEATHER ADVISORY FOR BLACK ICE IN EFFECT FOR THE ENTIRE CWA
THROUGH 10 AM... HOWEVER BASED ON PROJECTED HOURLY TEMPS... PORTIONS
OF THE NW PIEDMONT MAY NOT SURPASS THE FREEZING MARK UNTIL CLOSER TO
11 AM OR NOON... AND THUS THE ADVISORY MAY NEED TO BE EXTENDED
FORWARD IN TIME BY AN HOUR OR TWO. FINALLY... FAIR SKIES THIS
MORNING WILL GIVE WAY TO A QUICK INCREASE IN CLOUDS BY MIDDAY... AS
THE CLIPPER FRONT AND ASSOCIATED VORTICITY MAX NOW CROSSING THE OH
VALLEY AND MIDSOUTH ARE PROJECTED TO SWING THROUGH CENTRAL NC THIS
AFTERNOON. WITH A SHOT OF LOW LEVEL MOIST UPGLIDE AT 275-280K AHEAD
OF AND WITH THE FRONT... STEEP LOW LEVEL (925-700 MB) LAPSE RATES OF
7-8 C/KM... SURFACE WET BULB TEMPS NOT MUCH ABOVE FREEZING... AND
BUFR SOUNDINGS SHOWING GOOD SATURATION FROM JUST OFF THE SURFACE UP
THROUGH THE -20C LEVEL... ALL FOCUSED ON THE 17Z-01Z TIME FRAME...
EXPECT A BRIEF WINDOW OF SNOW SHOWERS WITH THE GREATEST COVERAGE
ACROSS THE NORTH HALF... AND A LOWER RISK OF A RAIN SHOWER/SNOW
SHOWER MIX ACROSS THE SOUTH WHERE SURFACE WET BULBS SHOULD GO ABOVE
FREEZING FOR MUCH OF THE DAY. WILL STICK WITH GOOD CHANCE POPS NORTH
TAPERING TO SLIGHT CHANCE POPS SOUTH. QPF SHOULD BE QUITE LIGHT
GIVEN THE FAST MOVEMENT... BUT WITH THE STEEP LAPSE RATES SUGGESTING
A CONVECTIVE CONTRIBUTION... WE COULD SEE A SHORT PERIOD OF HEAVIER
RATES... AND WOULDN`T BE AT ALL SURPRISED TO SEE A DUSTING TO A HALF
INCH OF SNOW IN SOME SPOTS ACROSS THE NORTHERN CWA. HIGHS FROM THE
MID 30S NORTH TO LOWER 40S SOUTH. -GIH
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY
FOR NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1017 AM EST WED FEB 18 2015
.SYNOPSIS...
AN ARCTIC FRONT AND POTENT UPPER LEVEL DISTURBANCE WILL BRING
SNOW SHOWERS OR EVEN A FEW HOUR PERIOD OF STEADIER SNOW TO THE
AREA TODAY INTO TONIGHT...WITH THE POTENTIAL FOR AN EXTENSIVE
NORTH-SOUTH BAND OF INTENSE...DANGEROUS SNOW SQUALLS MARCHING
ACROSS CENTRAL PENNSYLVANIA AND THE SUSQUEHANNA VALLEY LATER THIS
AFTERNOON AND EVENING. BITTER COLD TEMPERATURES AND SUBZERO WIND
CHILLS ARE EXPECTED TONIGHT...RIGHT INTO FRIDAY MORNING.
A GRADUAL WARM-UP WILL OCCUR THIS COMING WEEKEND...BUT WITH IT
WILL COME A BOUT OF WINTRY WEATHER AS LOW PRESSURE ORGANIZES AND
MOVES NORTHEAST FROM THE MID MISSISSIPPI VALLEY TO THE EASTERN
GREAT LAKES REGION.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
CLEARING SKIES AND CALM WINDS GREET US THIS MORNING AS ONLY MID TO
HIGH LEVEL CLOUDS REMAIN OVER MOST OF PA. CLOUDS WILL THICKEN
FROM THE WEST AS THE MORNING CONTINUES WITH INCREASING CHANCES OF
LIGHT SNOW SHOWERS FROM THE WEST CENTRAL MOUNTAINS TO THE
NORTHWEST MTNS. LIGHT SNOW HAS BEGUN IN THE NORTHWEST AND OVER THE
LAURELS...AND PRECIPITATION CHANCES WILL INCREASE AS THE DAY
CONTINUES.
THE SITUATION FOR TODAY LOOKING QUITE SIMILAR IN MANY WAYS TO
WHAT WE EXPERIENCED IN TERMS OF SNOW SQUALLS WITH THE LAST ARCTIC
FRONT ON SATURDAY.
LATEST...SHORT TERM MODELS AND 12Z OPERATIONAL GUIDANCE...ALONG
WITH HIGH RES MODELS CONTINUE TO SHOW THE AMPLIFYING UPPER TROUGH
TAKING ON A SLIGHT NEG TILT AS IT SWINGS THROUGH THE GLAKES AND
UPPER OHIO RIVER VALLEY...WITH RAPIDLY ERODING STABILITY
ACCOMPANYING THE FRONT AS IT ENTERS THE REGION.
A SIGNIFICANT AND RATHER STG SHORTWAVE WILL MOVE NE UP THE OHIO
RIVER VALLEY. THIS FEATURE WILL ALSO ACT TO ENHANCE LLVL
CONVERGENCE AND DEEP LAYER INSTABILITY ALONG AND JUST AHEAD OF
THE CFROPA. A HIGHLY UNUSUAL /AND ANOMALOUS/ NORTH-SOUTH RIBBON OF
MIXED LAYER CAPE OF 50-150 J/KG WILL FORM JUST AHEAD OF THE ARCTIC
BOUNDARY THIS AFTERNOON NEAR THE ALLEGHENY FRONT. LATEST HRRR IS
CURRENTLY SLOWING THE WAVES PROGRESS AND BREAKING APART THE LINE
AS IT MOVES EASTWARD. LATEST NAM12 SNOW SQUALL PARAMETERS SHOWING
ISALLOBARIC EFFECTS ON OVERALL WIND SPEED. FRONTAL PASSAGE STILL
PROGGED AROUND 00Z.
THE LINE OF SQUALLS IS EXPECTED TO BE NEAR A KELZ TO KUNV AND
KAOO LINE BETWEEN 21-00Z...THEN OVER THE SUSQ VALLEY AROUND
00-02Z. BRIEF PERIODS OF SUB 1/4SM SQUALLS ARE POSSIBLE AT THE
HEIGHT OF THE SYSTEM AS IT PUSHES EAST ACROSS THE REGION THIS
AFTERNOON AND EARLY THIS EVENING.
FOLLOWING THIS FRONT...MID AND UPPER FLOW WILL BE NEARLY PARALLEL
SUPPORTING ANAFRONT-LIKE PRECIP IN THE FORM OF A FEW TO SVRL HOUR
PERIOD OF LIGHT TO MDT SNOW -MAINLY ACROSS THE NW HALF OF THE
STATE.
MOST PLACES ACROSS CENTRAL PENN SHOULD SEE 1-2 INCHES OVER THE
NEXT 24 HOURS...WITH THE MTNS OF NRN PENN PICKING UP 2-3 INCHES
AND THE LAURELS SEE AS MUCH AS 3-5 INCHES BY EARLY THURSDAY
MORNING. A WINTER WEATHER ADVISORY WAS ISSUED FOR THE LAURELS /AND
COLLABORATED WITH SURROUNDING WFOS/ FROM NOON TODAY TO MIDNIGHT
TONIGHT.
THE CLEARING SKIES SHOULD HELP TO WARM TEMPS THIS
AFTERNOON...THOUGH THE REMAINING HIGH CLOUDS WILL REDUCE INCOMING
RADIATION. STILL EXPECT TEMPS IN THE LOWER TO MID TEENS ACROSS
THE WEST AND THE LOW- MID 20S ACROSS THE CENTRAL AND SERN PENN
VALLEYS...BEFORE FALLING STEADILY IN THE WAKE OF THE ARCTIC FRONT.
AS THE ARCTIC FRONT DROPS THROUGH THIS EVENING EXPECT GUSTY
NORTHWEST FLOW DEVELOPING LATER TODAY AND TONIGHT AND WIND CHILLS
WILL BECOME A FACTOR.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
WIND CHILL WARNINGS TONIGHT...BEGINNING AT MIDNIGHT FOR ALL OF
THE WESTERN AND NRN MTNS...WHILE WIND CHILL ADVISORIES WERE ISSUED
ELSEWHERE. THESE WIND CHILL PRODUCTS CONTINUE RIGHT THROUGH 15Z
FRIDAY AS THE COLD AIR MASS WILL MOVE OVER AND SIT OVER THE REGION
THROUGH FRIDAY.
LOWS TONIGHT WILL RANGE FROM -5 TO -10F ACROSS THE NW MTNS...TO
THE SINGLE DIGITS ABOVE ZERO IN THE SE.
HIGHS THURSDAY WILL STRUGGLE TO CLIMB ABOVE ZERO IN THE NW MTNS
/AND STAY JUST IN THE SINGLE DIGITS TO TEENS ELSEWHERE/ WITH
CONTINUED GUSTY NW WINDS UP TO 30-35 MPH AND OCNL FLURRIES AND
BANDS OF SNOW SHOWERS. THE SNOW SHOWERS COULD ADD ANOTHER COATING
TO 1/2 INCH IN THE CENTRAL RIDGE AND VALLEY REGION...AND 1-2
INCHES ACROSS THE ALLEGHENIES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF COVERING THE CONUS EAST
OF THE ROCKIES AT THE START OF THE LONG TERM PERIOD IS FORECAST
TO SHIFT EAST AND TRANSITION THE UPPER FLOW TO A ZONAL PATTERN BY
THE WEEKEND. CORE OF ARCTIC AIR ALOFT IS FORECAST TO DROP INTO NRN
PA THURSDAY AFTN/EVE...SUPPORTING THE SHIFT IN THE UPPER FLOW. IN
RESPONSE TO ADDITIONAL COLD AIR/ENERGY DROPPING SOUTH ALONG THE
FRONT RANGE OVER THE WEEKEND...THE UPPER FLOW OVER THE EAST IS
FORECAST TO TURN SWRLY INTO NEXT WEEK. AS A RESULT...VERY COLD
AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE REST
OF THE WORK-WEEK.
THE FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY HOLD THE POTENTIAL TO RISE ABOVE THE FREEZING
MARK OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED
MODERATION IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT
SHORTWAVE TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE
MID MISS VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY...
LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN
PA AND SNOW OVER THEN NORTH.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL FROPA...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING BELOW NORMAL...BUT NOT AS FAR BELOW AS IN
RECENT DAYS.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
MAINLY VFR CONDS THIS MORNING...THOUGH IFR FROM SNOWFALL HAS
OVERTAKEN BFD...AND THE LIGHT WINDS AND HZ IS CAUSING MVFR VSBYS
AT LNS. ANY PREDOMINATELY VFR CONDITIONS WILL TREND TO THE
DOWNSIDE WITH HIGH CONFIDENCE IN IFR/MVFR BY THE AFTERNOON OVER
THE WRN AND CNTRL TAFS...CORRESPONDING TO AN UPTICK IN SHSN
COVERAGE AND INTENSITY AS AN ARCTIC FRONT MOVES THROUGH THE
AIRSPACE. SHSN SHOULD EVENTUALLY REACH INTO THE ERN AIRFIELDS WITH
MVFR/IFR RESTRICTIONS EXPECTED LATE THIS AFTN INTO EARLY EVENING.
LLVL INSTABILITY WITH STEEP LAPSE RATES SUGGESTS A BAND OF BRIEFLY
INTENSE SNOW SQUALLS WILL ACCOMPANY THE ARCTIC FROPA WHICH MAY
RESULT IN RAPID DROP IN VISBYS AOB 1/2SM. HAVE INCLUDED 1HR TEMPO
OF 1/4 TO 1/2SM VISBYS BASED ON THE LATEST HRRR. SFC WINDS
INITIALLY FROM 200-230 DEGREES WILL SHIFT TO 270-300 BEHIND THE
FRONT WITH GUSTS 15-25MPH. PROLONGED IFR EXPECTED AT BFD/JST WITH
COLD NW UPSLOPE FLOW SHSN CONTINUING TONIGHT.
OUTLOOK...
THU...MVFR/IFR -SHSN WRN 1/3. MAINLY VFR CENTRAL AND ERN TAFS.
FRI...BCMG VFR. NO SIG WX.
SAT-SUN...MVFR/IFR LKLY WITH MIXED PCPN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ004>006-010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/CERU
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1024 AM EST WED FEB 18 2015
.SYNOPSIS...
ARCTIC COLD FRONT PLOWS THROUGH OUR AREA THIS AFTERNOON. RECORD
AND DANGEROUSLY COLD TEMPERATURES WILL BE FOUND TONIGHT THROUGH
FRIDAY. ANOTHER STORM SYSTEM ARRIVES THIS WEEKEND WITH A WINTER
WEATHER THREAT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM EST WEDNESDAY...
STRONG ARCTIC FRONT STILL ON TRACK TO CROSS THE MOUNTAINS EARLY
THIS AFTERNOON AND OUT EAST LATE IN THE DAY. VERY DYNAMIC SETUP
WITH VERY COLD AIR ALOFT ROTATING THROUGH THE 5H TROUGH WITH A
PASSING VORT AXIS ALONG THE BOUNDARY VERY SIMILAR TO A CONVECTIVE
SCENARIO IN THE SPRING. PROVIDED SOME HEATING/MOISTENING OF THE
BOUNDARY LAYER PER SW FLOW JUST AHEAD OF THE BOUNDARY ESPCLY BLUE
RIDGE EAST EXPECT SHALLOW CONVECTION TO DEVELOP OFF THE RIDGES
EARLY THIS AFTERNOON BEFORE SWEEPING EAST IN BROKEN BAND FASHION
LATER ON. LATEST SPC DAY1 OUTLOOK HAS GENERAL THUNDER OVER MUCH OF
THE CENTRAL/EAST SO INCLUDED THUNDER GIVEN SMALL FORECAST CAPE
AND SOME HEAVIER SNOW SQUALLS PER HRRR UNDER SUCH STRONG SURFACE-
7H LAPSES OFF FORECAST SOUNDINGS. THIS COULD TRANSLATE SOME
STRONGER WINDS TO THE GROUND WITHIN ANY OF THE HEAVIER SNOW
SHOWERS WITH A QUICK INCH OR TWO OF SNOW POSSIBLE.
THUS WENT AHEAD AND INCLUDED SOME THUNDER/GUSTY WIND MENTION
WHILE EXTENDING THE WESTERN WINTER WEATHER ADVISORY EAST TO THE
BLUE RIDGE TO COVER MORE IMPACT RELATED SNOWFALL WHICH MAY ONLY
LAST AN HOUR OR TWO RIGHT AHEAD OF THE FRONT. SOME OF THIS
CONVECTION LIKELY TO HEAD EAST INTO THE WARMER BOUNDARY LAYER
WHERE PLAN TO COVER WITH STATEMENTS FOR NOW PENDING LATER
COVERAGE. OTRW BUMPED UP POPS AND ROLLED POSSIBLE WIND ADVISORY
GUSTS INTO THE WINTER WEATHER ADVISORY. RAISED HIGH TEMPS A NOTCH
IN THE FAR WEST GIVEN CURRENT OBS AND OUT EAST WHERE THINK A
BETTER SHOT AT RECOVERY WITH SOME SPOTS PERHAPS NEAR 40 IF THE
FRONT DOES SLOW UP SOME.
PREVIOUS DISCUSSION AS OF 345 AM EST WEDNESDAY...
NOT MUCH OF BREAK FROM OLD MAN WINTER. ARCTIC FRONT UPSTREAM
ACROSS THE OHIO VALLEY WILL SHIFT EAST ACROSS US TODAY. WILL BE
DEALING FIRST WITH SNOW SHOWERS AND BLOWING SNOW. HIGH-RES MODELS
SEEMED TO HAVE A DECENT HANDLE ON UPSTREAM OBS. INSTABILITY
ACTUALLY INCREASES AT TIMES THROUGH THIS AFTERNOON ENOUGH THAT
SNOW SQUALLS WILL OCCUR. CANNOT RULE OUT THUNDER...BUT ITS
MARGINAL. SITUATION LOOKS SOMEWHAT SIMILAR TO WHAT WE HAD LAST
WEEKEND. THIS DEEPENING TROUGH TO PUSH ARCTIC AIR EAST BY THIS
EVENING. SNOW SHOWERS WILL BE MOST PREVALENT OVER THE MOUNTAINS
BUT AS THE AFTERNOON MOVES ON...EXPECT STREAMERS OF SNOW TO REACH
INTO THE PIEDMONT...WITH SOME AXIS OF FRONTOGENESIS OCCURRING THIS
EVENING ACROSS THE PIEDMONT WITH EPV ALSO IN PLACE...WHICH MAY
LEAD TO MORE COVERAGE EAST OF OUR AREA.
AS FAR AS TOTAL SNOWFALL...THROUGH MIDNIGHT TONIGHT WILL LIKELY
SEE 1 TO 3 INCHES IN THE MOUNTAINS...WITH UP TO 6 INCHES IN WRN
GREENBRIER AND HIGHER TERRAIN OF SW VA/NW NC. AS SUCH HAVE
EXTENDED THE WINTER WX ADVISORY TIL MIDNIGHT TONIGHT. AFTER THAT
THE WIND CHILL WARNING PRODUCT WILL INCLUDE ANY ADDITIONAL
ACCUMULATIONS THAT OCCUR INTO THURSDAY.
TEMPERATURES THIS MORNING WILL START TO RISE AHEAD OF THE FRONT
WITH HIGHS IN THE LOWER TO MID 30S SOUTHEAST TO TEENS/20S WEST.
TEMPS SHOULD FALL TO THE TEENS IN THE WEST BY EVENING WITH UPPER
20S EAST. ARCTIC AIR LAGS BEHIND THE ACTUAL FRONT SOME...SO A
DELAY IS EXPECTED IN THE PIEDMONT.
WINDS SHOULD BEGIN TO INCREASE WITH THE SNOW SHOWERS AND FRONT
TODAY. MODELS HAVE NEAR ADVISORY LEVEL GUSTS IN THE NC MTNS...BUT
NOT SEEING AS LOW OF AN INVERSION...SO SHOULD KEEP WINDS UNDER 50
MPH GUSTS.
AT MIDNIGHT...WIND CHILLS SHOULD START TO REACH INTO ADVISORY
LEVELS IN THE MOUNTAINS BUT QUICKLY DROP TO 20 BELOW BY
MORNING...WHILE THE PIEDMONT AND FOOTHILLS DROP TO 0 TO 10 BELOW
ZERO BY THURSDAY MORNING. PER COLLABORATION WITH NEIGHBORING NWS
OFFICES WE DECIDED TO RUN THE WIND CHILL HEADLINES THROUGH FRIDAY
MORNING...AS THURSDAY WILL NOT SEE TOO MUCH OF A WARMUP.
WILL DROP THE WINTER WX ADVISORY FOR BLACK ICE IN NC BY 7AM.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 AM EST WEDNESDAY...
A CLOSED UPPER LEVEL LOW WILL TRACK ACROSS PENNSYLVANIA THURSDAY.
THIS SYSTEM WILL BRING LIGHT UPSLOPE SNOW SHOWERS TO WESTERN SLOPES
WITH CLOUDS SPREADING EAST INTO THE PIEDMONT. CLOUDS AND LIGHT SNOW
IS THE LEAST OF OUR WORRIES AS AN ARCTIC AIRMASS WILL KEEP THE
REGION COLD WITH SINGLE DIGITS ACROSS THE MOUNTAINS AND MID TO UPPER
TEENS EAST DURING THE DAY THURSDAY. STRONG WINDS WILL ALSO BLOW
ACROSS THE AREA THURSDAY WITH A TIGHT PRESSURE GRADIENT FROM THE LOW
TO THE NORTH AND HIGH PRESSURE ENTERING THE OHIO VALLEY. THE
COMBINATION OF VERY COLD TEMPERATURES AND STRONG WINDS WILL KEEP
WIND CHILL VALUES BELOW ZERO FOR MUCH OF THE DAY. THE PIEDMONT WIND
CHILLS MAY GO ABOVE ZERO THURSDAY AFTERNOON FOR A FEW HOURS ONLY TO
DROP BACK DOWN THURSDAY NIGHT. FOR SIMPLICITY SAKE AND IMPACT FROM
THIS HISTORIC EVENT...WE WILL CONTINUE WITH WIND CHILL WARNINGS
ALONG AND WEST OF THE BLUE RIDGE AND ADVISORIES EAST OF THE BLUE
RIDGE INTO FRIDAY MORNING. IF HIGH PRESSURE BUILDS IN OVER THE AREA
ALLOWING WINDS TO DECOUPLE...WE COULD DOWN GRADE HEADLINES LATER. NO
MATTER HOW YOU LOOK AT IT...WIND OR NO WIND...IT WILL BE A BITTER
COLD PERIOD INTO THURSDAY INTO FRIDAY MORNING.
HIGH PRESSURE TRACKS ACROSS THE REGION FRIDAY. WITH A DRY AIRMASS
AND ABUNDANT SUNSHINE...TEMPERATURES WILL SEEMS MILD WITH HIGHS IN
THE 20S. HIGH PRESSURE SLIDES OFF THE VIRGINIA AND NORTH CAROLINA
COAST FRIDAY NIGHT...ALLOWING A WARM FRONT TO TRACK NORTH ACROSS THE
TENNESSEE-SOUTHERN OHIO VALLEYS. CLOUDS SHOULD HOLD OFF FRIDAY
EVENING AND WITH GOOD RADIATIONAL COOLING...SEND TEMPERATURES DOWN
INTO THE SINGLE DIGITS ACROSS MOUNTAIN VALLEYS AND POINTS EAST OF
THE BLUE RIDGE. WARM AIR WORKING IN ALOFT WILL KEEP RIDGES
TEMPERATURES 10F WARMER THAN EVERYONE ELSE.
ISENTROPIC LIFT AND SHORT WAVES ALONG THE WARM FRONT WILL PUSH
MOISTURE IN ACROSS SOUTHWESTERN VIRGINIA LATE FRIDAY NIGHT...THEN
OVER SPREAD THE REGION DURING THE DAY SATURDAY. PRECIPITATION LIKELY
TO START AS SNOW...THEN TRANSITION TO SLEET BEFORE BECOMING ALL RAIN
BY LATE IN THE AFTERNOON. PRECIPITATION FALLING INTO EXITING RIDGE
WILL CREATE AN INSITU WEDGE. MODELS ARE KEEPING TEMPERATURES IN A
30F-33F RANGE ALONG THE BLUE RIDGE AND NORTH OF HWY 460 INTO
SATURDAY AFTERNOON. THESE AREAS WILL KEEP SNOW LONGER UNLESS WARM
NOSES IS STRONGER AND IN THAT CASE...SLEET INTO THE AFTERNOON. FOR
NOW...KEEPING P-TYPE AS RAIN/SNOW. WARMER AIR OVER TAKE THE FORECAST
AREA SATURDAY NIGHT FOR ALL P-TYPE TO BE RAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 315 AM EST WEDNESDAY...
INSITU WEDGE WILL ERODE OVERNIGHT AS LOW PRESSURE TRACKS INTO THE
OHIO VALLEY. PRECIPITATION INTENSITY WILL WANE OVERNIGHT AS THE WARM
FRONT TRACKS NORTH AND WE AWAIT THE COLD FRONTAL PASSAGE SUNDAY
AFTERNOON. P-TYPE SHOULD BE ALL LIQUID (RAIN/DRIZZLE) BY LATE
SATURDAY NIGHT INTO SUNDAY. THE FRONT CROSSES THE MOUNTAINS SUNDAY
AFTERNOON...THEN THE PIEDMONT EARLY IN THE EVENING. TEMPERATURES
WILL GET A BOOST AHEAD OF THE COLD FRONT WITH UPPER 40S TO LOWER 50S
FORECASTED FOR SUNDAY. TEMPERATURES DROP BACK INTO THE 20S SUNDAY
NIGHT WITH SCATTERED MOUNTAIN SNOW SHOWERS INTO THE DAY MONDAY.
TEMPERATURES MONDAY AND TUESDAY WILL RUN BELOW NORMAL.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM EST WEDNESDAY...
EXPECTING A BAND OF MODERATE SNOW SHOWERS/SNOW SQUALLS TO
ACCOMPANY AN ARCTIC FRONT TODAY...REACHING BLF/LWB IN THE 15-17Z
TIME FRAME...BCB/ROA 17-19Z...AND LYH/DAN 19-21Z. HAVE TEMPO
GROUPS FOR POTENTIAL STRONG WIND GUSTS AND LOWER VSBYS/CIGS AT ALL
SITES. EXPECT TO RETURN TO VFR EAST OF THE MTNS BY EVENING WITH
SNOW SHOWERS PERSISTING AT BLF/LWB INTO THE EVENING TAPERING OFF
OVERNIGHT...BUT CIGS STAYING MVFR. WINDS WILL BE SOUTHWEST AND
LIGHT THIS MORNING INCREASING AND VEERING TO THE WEST WITH THE
SNOW SHOWERS AND BEHIND THE FRONT. GUSTS TO 25 TO 35 KTS NOT OUT
OF THE QUESTION.
UPSLOPE MVFR TO CONTINUE INTO THURSDAY IN SE WV...WITH VFR EAST.
WIDESPREAD VFR RETURNS FOR ALL LOCATIONS THURSDAY NIGHT INTO
FRIDAY UNDER DRY/ARCTIC HIGH PRESSURE. CLOUDS WILL INCREASE
FRIDAY NIGHT BUT LIKELY STILL VFR.
ANOTHER COMPLEX STORM SYSTEM WILL AFFECT THE AREA SATURDAY INTO
SUNDAY WITH SUB VFR CONDITIONS AND A MIX OF WINTER WEATHER.
&&
.CLIMATE...
LOW MAXIMUM (COLDEST HIGH) TEMPERATURE RECORDS FOR THURSDAY (FEB 19).
ROA 28/1958
LYH 25/1903
DAN 20/1979
BLF 20/1960
LWB 28/2006
RNK 10/1958
LOW MINIMUM (COLDEST LOWS) TEMPERATURE RECORDS FOR THURSDAY AND FRIDAY.
2/19 2/20
ROA 7/1979 9/1979
LYH 8/1903 7/1896
DAN 11/1973 10/1979
BLF 3/1993 8/1960
LWB 3/2006 6/1979
RNK -2/1958 2/1972
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VAZ011>014-016>020-022>024-032.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ007-009>020.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007-
009-010-015.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ022>024-032>035-043>047-058-059.
NC...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NCZ003-
019-020.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ001-002-018.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-
002-018.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ003>006-019-020.
WV...WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR WVZ042>044-507-508.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
WVZ042>044-507-508.
&&
$$
SYNOPSIS...JH/PH
NEAR TERM...JH/WP
SHORT TERM...RCS
LONG TERM...KK
AVIATION...AMS/JH/WP
CLIMATE...PH
AREA FORECAST DISCUSSION
NWS ALBANY NY
301 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
AS OF 1235 PM EST...WE ACTUALLY NEEDED TO RAISE TEMPERATURES SEVERAL
DEGREES AS MOST AREAS WERE ALREADY APPROACHING THE PREVIOUSLY
ADVERTISED HIGHS. THIS MEAN HIGHS SHOULD REACH THE UPPER 20S TO NEAR
30 WELL SOUTH OF THE CAPITAL REGION...MID 20S LOCALLY IN THE CAPITAL
REGION...CLOSER TO 20 FURTHER NORTH. WITH LITTLE OR NO WIND...THIS
WILL MAKE THE COLD EASEIR TO TAKE TODAY.
ALSO...SLOWED DOWN THE ARRIVAL OF CLOUDS AND SNOW SHOWERS JUST A
LITTLE HAS THE DRY AIR HOLDS TIGHT.
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/HWJIV
SHORT TERM...HWJIV
LONG TERM...IRL
AVIATION...HWJIV/NAS
HYDROLOGY...FRUGIS/HWJIV
AREA FORECAST DISCUSSION
NWS ALBANY NY
1235 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
AS OF 1235 PM EST...WE ACTUALLY NEEDED TO RAISE TEMPERATURES SEVERAL
DEGREES AS MOST AREAS WERE ALREADY APPROACHING THE PREVIOUSLY
ADVERTISED HIGHS. THIS MEAN HIGHS SHOULD REACH THE UPPER 20S TO NEAR
30 WELL SOUTH OF THE CAPITAL REGION...MID 20S LOCALLY IN THE CAPITAL
REGION...CLOSER TO 20 FURTHER NORTH. WITH LITTLE OR NO WIND...THIS
WILL MAKE THE COLD EASEIR TO TAKE TODAY.
ALSO...SLOWED DOWN THE ARRIVAL OF CLOUDS AND SNOW SHOWERS JUST A
LITTLE HAS THE DRY AIR HOLDS TIGHT.
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/HWJIV/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...11/NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1234 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/HWJIV/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...11/NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1211 PM EST WED FEB 18 2015
.SYNOPSIS...
CLOUDS WILL INCREASE THROUGH THE DAY AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THIS FRONT WILL BRING SOME SNOW
SHOWERS AND SNOW SQUALLS TO THE REGION THIS EVENING INTO TONIGHT.
BITTER COLD TEMPERATURES...ALONG WITH A FEW ADDITIONAL SNOW
SHOWERS...WILL BE IN PLACE ACROSS THE REGION FOR THURSDAY INTO
FRIDAY. ANOTHER STORM SYSTEM WILL IMPACT THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM EST...A STRONG SHORTWAVE AND ASSOCIATED SFC COLD
FRONT IS SITUATED UPSTREAM OF THE REGION OVER THE GREAT LAKES.
SOME MID AND HIGH LEVEL CLOUDS HAVE STARTED TO MOVE INTO OUR
AREA...BUT THE MAJORITY OF THESE CLOUDS HAVE BEEN RATHER THIN.
WITH A DEEP SNOWPACK AND LIGHT WINDS IN PLACE...TEMPS HAVE BEEN
VERY COLD SO FAR THIS MORNING...WITH MOST AREAS ONLY IN THE SINGLE
DIGITS TO SLIGHTLY BELOW ZERO.
CLOUDS WILL CONTINUE TO LOWER AND THICKEN THROUGHOUT THE DAY AS
THE ARCTIC FRONT CONTINUES TO MOVE EASTWARD TOWARDS THE AREA. MOST
AREAS LOOK TO BE MOSTLY CLOUDY BY AFTERNOON. IT SHOULD STAY DRY
ACROSS THE REGION THROUGH THE EARLY EVENING...AS THE LATEST 09Z
3KM HRRR SHOWS A BAND OF HEAVY SNOW SHOWERS STILL BACK OVER CNY
BETWEEN THE FINGER LAKES AND THE SYRACUSE AREA BY ABOUT 5-6 PM.
WILL START TO RAISE POPS FOR WESTERN AREAS FOR THE LATE AFTN/EARLY
EVENING IN CASE THIS SPEEDS UP...BUT MOST AREAS WON/T SEE ANY SNOW
UNTIL TONIGHT.
HIGH TEMPS TODAY WILL BE A LITTLE WARMER THAN TUESDAY...BUT STILL
BELOW NORMAL...WITH TEMPS RANGING FROM THE MID TEENS IN THE
ADIRONDACKS TO THE MID 20S IN THE HUDSON VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE ARCTIC COLD FRONT WILL BE PASSING FROM WEST TO EAST ACROSS THE
REGION TONIGHT. THE FRONT WILL BE SLOWED IN ITS PROGRESS...AS A
WEAK WAVE OF LOW PRESSURE DEVELOPS ALONG THE COLD/OCCLUDED
BOUNDARY. THE 00Z WFO BTV 4KM WRF SHOWS AN AREA OF SNOW SHOWERS
AND EMBEDDED SQUALLS IMPACTING THE REGION FROM WEST TO EAST DURING
THE OVERNIGHT HOURS. THE 00Z/06Z NAM ALSO SUGGESTS THIS WILL
OCCUR...ALTHOUGH THERE ARE SOME SLIGHT DIFFERENCES IN THE TIMING
DUE TO THE SLOW NATURE OF THE FRONTAL BOUNDARY. HAVE RAISED POPS
TO LIKELY FOR A FEW HOURS IN MOST LOCATIONS...WITH A LIGHT
ACCUMULATION OF 1-3 INCHES EXPECTED TONIGHT INTO THURSDAY
MORNING...WITH THE HIGHEST AMOUNTS FOR THE HIGHER ELEVATIONS. ALTHOUGH
QPF AMOUNTS ARE LIGHT...RATIOS ARE EXPECTED TO BE RATHER HIGH...AS
THE NAM BUFKIT SOUNDING SHOWS GOOD LIFT /OMEGA/ THROUGH THE
OPTIMAL DENDRITIC SNOW GROWTH LAYER. TEMPS LOOK TO COOL OFF
QUICKLY BEHIND THE BOUNDARY...WITH MINS LOWEST FOR WESTERN AREAS
/ZERO TO 5/ AND HIGHEST FOR EASTERN/SOUTHERN AREAS /GENERALLY 10
TO 15/.
WIDESPREAD SNOW SHOWERS WILL BE ONGOING THURSDAY MORNING...BUT
WILL BE TAPERING OFF BY MIDDAY FOR MOST AREAS...AS THE FRONT
CONTINUES TO PUSH EASTWARD...AND THE WAVE ON THE BOUNDARY RE-
DEVELOPS AND RAPIDLY STRENGTHENS OFF THE EASTERN NEW ENGLAND
COAST. TEMPS WON/T RISE TOO MUCH ON THURSDAY WITH THE STRONG COLD
AIR ADVECTION IN PLACE...AS 850 HPA TEMPS FALL TO -20 TO -25
DEGREES C. HIGHS WILL ONLY REACH THE SINGLE DIGITS TO MID TEENS.
SOME ADDITIONAL UPSLOPE SNOW MAY OCCUR WITH IN THE NW FLOW FOR
THE HIGH TERRAIN AREAS OF WESTERN NEW ENGLAND...AND SOME LAKE
ENHANCED SNOW SHOWERS COULD ALSO BE OCCURRING INTO THE MOHAWK
VALLEY/SCHOHARIE COUNTY THANKS TO THE FLOW MOVING ACROSS LAKE
ONTARIO. SOME ADDITIONAL ACCUMULATION OF AN INCH OR TWO IS
POSSIBLE FOR THESE AREAS.
WINDS WILL BE STARTING TO PICK UP BY THURSDAY AFTERNOON THANKS TO
THE INCREASING PRESSURE GRADIENT...AND WILL BE GUSTING 20-30 MPH
AT TIMES. THIS LOOK TO CONTINUE INTO THURSDAY NIGHT AS WELL...AND
TEMPS WILL BE FALLING TO ZERO TO -15 DEGREES F FOR LOW TEMPS FOR
THURSDAY NIGHT. WITH THE STRONG WINDS AND COLD TEMPS...WIND
CHILLS WILL CERTAINLY BE AN ISSUE. ADVISORY LEVEL WIND CHILLS
APPEAR LIKELY FOR MOST AREAS...AND A FEW SPOTS IN THE
ADIRONDACKS/CATSKILLS COULD POTENTIALLY REACH WARNING LEVELS AS
WELL. WILL CONTINUE TO HIGHLIGHT THESE THREATS IN THE HWO
STATEMENT. OUTSIDE OF THE BRUTALLY COLD TEMPS...SOME LINGERING
HIGH TERRAIN SNOW SHOWERS/FLURRIES ARE POSSIBLE...ALTHOUGH NOT
MUCH ADDITIONAL ACCUMULATION IS EXPECTED.
BITTER COLD TEMPS AND LOW WIND CHILL WILL REMAIN IN PLACE FOR
FRIDAY...ALTHOUGH WINDS WILL START TO REDUCE BY LATER IN THE DAY.
OUTSIDE A FEW FLURRIES/SNOW SHOWERS FOR THE WESTERN
ADIRONDACKS...NO PRECIP IS EXPECTED. MAX TEMPS WILL ONLY REACH THE
SINGLE DIGITS TO LOW TEENS...WITH A FEW SPOTS IN THE HIGH TERRAIN
REMAINING BELOW ZERO.
ANOTHER BITTER COLD NIGHT IS EXPECTED FOR FRIDAY NIGHT...BUT WIND
CHILLS WON/T BE AN ADDITIONAL CONCERN THANKS TO A LIGHT TO CALM
WINDS. STILL...TEMPS WILL BE VERY COLD...WITH MOST AREAS BELOW
ZERO ONCE AGAIN...AND SOME HIGH TERRAIN LOCATIONS -10 TO -20
DEGREES F. IT SHOULD REMAIN DRY...WITH A PARTLY TO MOSTLY CLEAR
SKY...AS HIGH PRESSURE SLIDES BY TO THE SOUTH OF THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
APPROACHING UPPER ENERGY WILL RESULT IN THICKENING CLOUDS AND SLOWLY
INCREASING COVERAGE OF LIGHT SNOW. WARM ADVECTION WILL INCREASE...
AS WILL ISENTROPIC LIFT. SO HIGHS SATURDAY IN THE UPPER TEENS TO MID
20S...WITH JUST CHANCES FOR LIGHT SNOW IN THE AFTERNOON.
COVERAGE OF PRECIPITATION WILL INCREASE SATURDAY NIGHT INTO
SUNDAY...AS WILL WARM ADVECTION AND ISENTROPIC LIFT. LOW LEVEL JET
ENERGY WILL SPREAD NORTH AND EAST...ENHANCING THE WARM ADVECTION...
ESPECIALLY SUNDAY. THERE ARE SOME CONFLICTS COMPARING DETERMINISTIC
GUIDANCE AND ENSEMBLE GUIDANCE. DETERMINISTIC GUIDANCE SUGGESTS A
PRECIPITATION TRANSITION TO MIXED PRECIPITATION OR COLD RAIN FOR THE
MUCH OF THE FORECAST AREA SUNDAY...WHILE ENSEMBLE MEAN THERMAL
PROFILES SUGGEST THE DETERMINISTIC GUIDANCE IS ON THE WARMER SIDE OF
THE ENSEMBLE RANGE.
THE MEAN EASTERN NORTH AMERICAN UPPER TROUGH WILL HAVE TO RETROGRADE
QUITE A BIT FOR ENOUGH WARM AIR TO FLOOD THE EASTERN U.S. TO BRING
RAIN DURING AN OTHERWISE SNOWY AND COLD WINTER. THERE IS STILL LOTS
OF TIME TO WATCH THE DEVELOPMENT OF THIS SYSTEM...AND UNTIL THERE
ARE CLEAR SIGNALS FOR MIXED PRECIPITATION OR COLD RAIN...WILL
INDICATE SNOW IN MOST AREAS THROUGH SUNDAY...WITH THE EXCEPTION OF
PARTS OF THE EASTERN CATSKILLS...MID HUDSON VALLEY AND NW CT...WHERE
RAIN AND SNOW WILL BE INDICATED. HIGHS SUNDAY AROUND 30 TO THE MID
30S...MID TO UPPER 20S NORTHERN AREAS.
ONCE THE SYSTEM EXITS SUNDAY NIGHT...ANOTHER PUSH OF VERY COLD AIR
SPILLS INTO THE REGION...WITH MUCH BELOW NORMAL TEMPERATURES. HIGHS
MONDAY IN THE TEENS TO LOWER 20S...SOME UPPER SINGLE NUMBERS IN THE
SOUTHERN ADIRONDACKS. HIGHS TUESDAY IN THE MID TEENS TO LOWER 20S.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
CIRRUS CLOUDS HAVE ALREADY STREAMED ACRS THE TAF SITES ALONG WITH
SOME MID LEVEL CLOUDS AHEAD OF AN APPROACHING COLD FRONT. OVERALL
CLOUDS WILL THICKEN AND LOWER THIS AFTERNOON AND EVENING AS THE
COLD FRONT MOVES INTO THE REGION BRINGING CHANCE OF SNOW SHOWERS
TO THE AREA...MAINLY AFTER 00Z/THU. KEEPING VFR CONDITIONS WITH
VCSH UNTIL AROUND 06Z...WHEN MANY AREAS SHOULD SEE SOME
INTERMITTENT SNOW OR SNOW SHOWERS. MVFR CEILINGS AND VISIBILITIES
SHOULD ACCOMPANY THE SNOW LOWERING TO IFR CONDITIONS THURSDAY
MORNING. WINDS CALM TO LIGHT AND VARIABLE THROUGH 06Z AND THEN
BCMG NORTHWEST 10-14KTS THURSDAY MORNING.
OUTLOOK...
WED NIGHT-THU: MODERATE OPERATIONAL IMPACT. CHC -SHSN.
THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SAT-SUN: MODERATE OPERATIONAL IMPACT. CHC SN.
&&
.HYDROLOGY...
ICE WILL CONTINUE TO THICKEN ON AREA RIVERS...STREAMS...LAKES...AND
PONDS...AS CONTINUED BELOW NORMAL TEMPERATURES REMAIN IN PLACE
THROUGH THE REMAINDER OF THE WEEK. TEMPERATURES LOOK TO STAY BELOW
FREEZING THROUGH SATURDAY.
ANY PRECIP...ALL IN THE FORM OF SNOW...WILL BE FAIRLY LIGHT OVER
THE NEXT FEW DAYS. SOME SNOW SHOWERS ARE POSSIBLE BETWEEN TODAY
AND TOMORROW...BUT THIS WILL HAVE LITTLE TO NO IMMEDIATE IMPACT ON
AREA WATERWAYS. SOME GAGES WILL EXPERIENCE ICE EFFECTS...AND SOME
ERRONEOUS DATA MAY BE SEEN FROM TIME TO TIME.
A STORM SYSTEM WILL IMPACT THE REGION OVER THE WEEKEND WITH SOME
ADDITIONAL PRECIPITATION...MAINLY ON SUNDAY. IT IS STILL UNCLEAR
IN WHAT FORM THIS PRECIP WILL BE /RAIN...SNOW...OR MIXED
PRECIPITATION/ AND EXACT AMOUNTS ARE STILL FAR FROM CERTAIN. WE
WILL NEED TO MONITOR THE POTENTIAL FOR HOW THIS STORM MAY IMPACT
THE HYDROLOGIC AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/11
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...11/NAS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1147 AM CST WED FEB 18 2015
.SHORT TERM...
315 AM CST
THROUGH THURSDAY...
A MASSIVE UPPER LOW/TROUGH CENTERED OVER
NORTHERN ONTARIO CONTINUES TO BE SPREAD ACROSS MOST OF NORTH
AMERICA. AN EMBEDDED SHORTWAVE IS TRACKING SOUTHEAST ACROSS SOUTHERN
WISCONSIN/NORTHERN IOWA AND WILL CROSS THE LOCAL AREA THROUGH THE
MORNING. WATER VAPOR SHOWS SHARP RIDGING OVER THE WEST COAST
EXTENDING WELL INTO THE YUKON/NUNAVUT WITH A STRAIGHT NORTH/SOUTH
TRAJECTORY DOWN THE WEST FLANK OF THE BIG TROUGH INTO THE PLAINS.
EVENING UPPER AIR ANALYSIS SHOWS H85 TEMPS OF -28C INTO NORTHERN
MINNESOTA BEHIND THE APPROACHING SHORTWAVE AND ON TRACK TO WORK INTO
THE LOCAL AREA LATER TODAY. AT THE SURFACE...A BROAD AREA OF LOW
PRESSURE STRETCHES FROM WESTERN QUEBEC SOUTHWEST TO LAKE HURON WITH
A SECONDARY LOW CIRCULATION OVER LOWER MICHIGAN. A COLD FRONT
EXTENDS SOUTHWEST FROM THE CENTRAL WISCONSIN ACROSS IOWA AND WILL
CROSS THE AREA THIS MORNING. THE LARGER SCALE ASCENT AND THE INFLUX
OF COLD AIR IS DRIVING AREAS OF LIGHT SNOW WITH SOME EMBEDDED SNOW
SHOWERS. THIS ACTIVITY WILL WORK ACROSS THE AREA THROUGH MID
MORNING. OVERALL IT WILL REMAIN LIGHT BUT DO EXPECT MORE INTENSE
RETURNS TO BE EMBEDDED WITHIN THE BROADER AREA OF LIGHT
SNOW...ESPECIALLY AFTER DAYBREAK. A FEW TENTHS OF ACCUMULATION IS
POSSIBLE WITH THE MORE PERSISTENT SHOWERS WITH AROUND A HALF INCH
NOT OUT OF THE QUESTION GIVEN THAT THE SNOW WILL BE FLUFFY BUT MANY
AREAS MAY SEE LITTLE MORE THAN A DUSTING. CONTINUED COLD
ADVECTION/CYCLONIC FLOW WILL SUPPORT FLURRIES OR SOME LIGHT SNOW
THROUGH THE REST OF THE DAY ONCE THE MAIN WAVE HAS DEPARTED. LAKE
EFFECT SNOW SHOWERS WILL BE OCCURRING EAST OF LAKE MICHIGAN AND WILL
LIKELY PERIODICALLY AFFECT PORTIONS OF PORTER COUNTY. FAR NORTHEAST
SECTIONS ARE MOST FAVORED FOR LIGHT ACCUMULATION...POSSIBLY AROUND
AN INCH.
COLD ADVECTION WILL PERSIST THROUGH THE DAY. HIGH TEMPS WILL BE A
LITTLE TRICKY GIVEN THAT THERE WILL PROBABLY BE AT LEAST SOME BREAKS
OF SUNSHINE FROM LATE MORNING THROUGH THE AFTERNOON. THE CORE OF THE
COLDEST AIR DOES NOT ARRIVE UNTIL THIS EVENING SO THERE SHOULD BE AT
LEAST SOME MODEST RECOVERY FROM MORNING TEMPS BEFORE THEY LEVEL OFF
AND PROBABLY FALL SOMEWHAT DURING THE AFTERNOON. THIS WILL PUT HIGHS
IN THE SINGLE DIGITS FOR MOST AREAS THOUGH THE SOUTHEAST THIRD OF
THE AREA MAY SEE READINGS OF 10 OR JUST ABOVE. HIGH PRESSURE WILL BE
SPREADING INTO THE MISSISSIPPI RIVER VALLEY THROUGH TONIGHT KEEPING
THE LOCAL AREA IN THE PRESSURE GRADIENT BETWEEN IT AND LOW PRESSURE
TO THE EAST. THIS WILL KEEP A STEADY NORTHWEST BREEZE IN PLACE
KEEPING TEMPS FROM RADIATING OUT BUT LOWS WILL STILL BE BITTERLY
COLD IN THE -4 TO -10 OR SO RANGE. WIND CHILLS WILL BE PUSHED TO -20
TO -30 SO WILL ISSUE A WIND CHILL ADVISORY FROM THIS EVENING THROUGH
MUCH OF THURSDAY MORNING. THE BIG UPPER TROUGH WILL SHIFT EAST
THURSDAY ALLOWING FOR SOME WARMING OF THE MID LEVELS BY LATE DAY.
THE SURFACE HIGH WILL BE OVERHEAD BY AFTERNOON SO WEAK MIXING WILL
NOT BE ABLE TO TAKE ADVANTAGE OF THE WARMING ALOFT. THIS WILL LIKELY
KEEP HIGHS IN THE MID SINGLE DIGITS BUT THE WILD CARD WILL BE THE
SUN WHICH IS QUITE STRONG AND WITH AN OLD SNOW PACK MAY BE ABLE TO
PROVIDE AN EXTRA FEW DEGREES OVER FORECAST HIGHS. REGARDLESS IT WILL
BE COLD AND 3 OF THE 4 RECORD TEMPS OUTLINED BELOW WILL BE IN
JEOPARDY THURSDAY. WINDS WILL BE MUCH LIGHTER THURSDAY NIGHT
ALLOWING FOR BETTER RADIATIONAL COOLING BUT MID/HIGH CLOUDS WILL BE
APPROACHING FROM THE WEST WHICH COULD ALLOW FOR SOME WARMING LATE.
SOME NORTHERN AREAS MAY NEED A WIND CHILL ADVISORY WITH WIND CHILLS
IN THE LOWER MINUS 20S.
MDB
&&
.LONG TERM...
315 AM CST
FRIDAY THROUGH TUESDAY...
THE UPPER FLOW WILL BE FLATTENING FRIDAY AS
THE BIG TROUGH CONTINUES EAST AND A WEAK UPPER TROUGH WORKS
SOUTHEAST INTO THE NORTHERN PLAINS. WARM ADVECTION WILL CONTINUE
ALOFT AND WITH THE SURFACE HIGH SHIFTING EAST SOUTHERLY FLOW WILL
DEVELOP AT THE SURFACE LEADING TO A MODERATION OF TEMPS. THE WARM
ADVECTION IN ADVANCE OF THE UPPER TROUGH/CLIPPER WILL BRING
INCREASED CLOUD COVER AND MAYBE SOME LIGHT SNOW SO WILL CARRY LOW
POPS FRIDAY. THINGS BECOME MORE INTERESTING AND COMPLEX FRIDAY NIGHT
AND SATURDAY AS A LARGER SCALE TROUGH DIGS INTO THE DESERT
SOUTHWEST. THIS WILL TRIGGER SURFACE LOW DEVELOPMENT ACROSS TEXAS
WITH AN INVERTED TROUGH/WARM FRONT DEVELOPING TO THE NORTHEAST. THE
SFC LOW WILL LIFT NORTHEAST COMBINING WITH AN OPEN GULF TO BRING A
GOOD PUSH OF MOISTURE NORTHEAST WITH IT. THE SIGNAL FOR THIS SYSTEM
HAS BEEN IN PLACE FOR SEVERAL DAYS BUT TRACK/STRENGTH DETAILS HAVE
BEEN INCONSISTENT. TYPICALLY A FURTHER SOUTH TRACK WOULD BE FAVORED
COMING OUT OF SUCH A STRONG ARCTIC BLAST BUT WITH THE INITIAL
TROUGH/CLIPPER AND DE-AMPLIFICATION OF THE UPPER FLOW BEFORE THE
MAIN TROUGH DRIVING THIS SYSTEM COMES INTO PLAY THE MID LEVEL
THERMAL GRADIENT WILL BE ABLE TO BE PUSHED BACK TOWARD THE AREA. IT
SEEMS THAT GUIDANCE MAY CONTINUE TO FAVOR A NORTHWARD TREND...WHICH
HAS BEEN THE TREND WITH MOST OF THESE SOUTHERN SYSTEMS THIS WINTER.
THIS WILL BE SOMETHING TO WATCH AND FOR NOW SOUTHEAST AREAS WILL BE
AT GREATEST RISK TO HAVE PRECIP FALL SO WILL CONTINUE WITH HIGHEST
POPS IN THESE AREAS. TEMP DETAILS WILL ALSO DEPEND ON THE TRACK BUT
LOWER 30S LOOK GOOD FOR NOW...WITH PRECIP TYPE POSSIBLY BECOMING AN
ISSUE.
COLDER AIR WILL SPREAD IN BEHIND THIS SYSTEM AS CANADIAN HIGH
PRESSURE ONCE AGAIN MOVES INTO THE CENTRAL U.S. SEVERAL UPPER
TROUGHS/CLIPPERS LOOK TO CROSS THE REGION EARLY NEXT WEEK CARVING
OUT ANOTHER BIG UPPER TROUGH SO THE MILDER AIR OF FRIDAY/SATURDAY
WILL BE SHORT LIVED WITH COLDER THAN NORMAL ARCTIC AIR EXPECTED TO
TAKE OVER FOR MUCH OF NEXT WEEK. IN OTHER WORDS THE CONDITIONS OF
THE RECENT FEW DAYS LOOK TO BE REPEATED TEMP AND PRECIP WISE WITH
BOUTS OF LIGHT SNOW WITH EACH PASSING WAVE.
MDB
&&
.CLIMATE...
WHILE THE COLDEST AIR ALOFT ARRIVES WEDNESDAY...THE COLDEST SURFACE
TEMPERATURES MAY RESULT ON THURSDAY FEBRUARY 19TH...WHICH RIGHT NOW
APPEARS COULD JEOPARDIZE SOME RECORDS...ESPECIALLY THE RECORD LOW
MAXIMUM TEMPERATURES.
FEB 19TH
RECORD LOW RECORD LOW MAX
CHICAGO -7 (1936) 9 (1936)
ROCKFORD -16 (1979) 7 (1959)
MTF/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* FLURRIES OR BRIEF LIGHT SNOW SHOWERS POSSIBLE THROUGH THIS
AFTERNOON.
* MVFR CEILINGS POSSIBLE EARLY THIS AFTERNOON.
* GUSTY NORTHWEST WINDS THROUGH THE AFTERNOON.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
FLURRIES AND LIGHT SNOW SHOWERS CONTINUE ACROSS THE AREA EARLY
THIS AFTERNOON AND WILL LIKELY PERSIST THROUGH THE
AFTERNOON...PERIODICALLY MOVING OVER THE TERMINALS. IF THIS WERE
TO OCCUR...EXPECT ANY SNOW TO BE LIGHT AND BRIEF. CURRENT MVFR
CEILINGS IN PLACE SHOULD NOT LAST LONG THIS AFTERNOON...BUT BECOME
VFR. THESE CLOUDS WILL THEN DIMINISH AS WELL AS THE WINDS LATER
THIS EVENING...BUT WITH A STEADY NORTHWEST WIND CONTINUING TONIGHT
INTO THURSDAY MORNING.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE WITH FLURRIES/SNOW SHOWERS.
* HIGH CONFIDENCE WITH MVFR CEILINGS AND DURATION.
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR. LIGHT AND VARIABLE WINDS.
FRIDAY...CHANCE OF SN WITH IFR POSSIBLE. MODERATELY STRONG SOUTH
WINDS.
SATURDAY...CHANCE OF MVFR/IFR AND SN.
SUNDAY...MVFR CIGS POSSIBLE. SLIGHT CHANCE OF -SN EARLY.
MONDAY...PRIMARILY VFR.
TUESDAY...SLIGHT CHANCE OF SNOW SHOWERS WITH MVFR TO IFR
POSSIBLE.
KJB
&&
.MARINE...
117 AM CST
A PERIOD OF STRONG NORTHWESTERLY WINDS IS STILL EXPECTED TO DEVELOP
ACROSS THE LAKE TODAY INTO TONIGHT. THE SURFACE PRESSURE GRADIENT
WILL TIGHTEN IN THE WAKE OF A SURFACE LOW...CURRENTLY SHIFTING
EASTWARD OVER THE UPPER GREAT LAKES REGION...AND AHEAD OF AN
ARCTIC SURFACE HIGH SHIFTING OVER THE NORTHERN PLAINS. IT APPEARS
THESE STRONG NORTHWEST WINDS WILL RANGE BETWEEN 30 KT AND SOME LOW
END 35 KT GALES...ESPECIALLY ACROSS THE SOUTHERN HALF OF LAKE
MICHIGAN. THE CURRENT HEADLINES FOR GALES AND FREEZING SPRAY
APPEAR TO BE ON TARGET...SO NO CHANGES ARE PLANNED AT THIS TIME.
HOWEVER...WE WILL NEED TO WATCH FOR THE POSSIBILITY OF A TIME
EXTENSION OF THE GALE/FREEZING SPRAY HEADLINE THROUGH THE NIGHT
TONIGHT...AS FORECAST GUIDANCE SUGGESTS THAT THE WINDS COULD
REMAIN ELEVATED THROUGH EARLY THURSDAY MORNING AS THE COLD ARCTIC
AIR MASS CONTINUES TO FILTER OVER THE LAKE.
WINDS WILL EASE FOR A PERIOD LATER THURSDAY AS THE SURFACE RIDGE OF
HIGH PRESSURE BEGINS TO SHIFT OVER THE WESTERN LAKES REGION.
HOWEVER...IT APPEARS THAT WINDS WILL QUICKLY PICK UP OUT OF THE
SOUTH BY FRIDAY AS ANOTHER CLIPPER SYSTEM TRACKS ACROSS SOUTHERN
CANADA. THIS LOOKS TO RESULT IN 30 KT SOUTHERLY WINDS AND MORE
FREEZING SPRAY LAKE-WIDE ON FRIDAY.
ANOTHER STORM SYSTEM LOOKS TO DEVELOP AND SHIFT SOUTH OF THE LAKE ON
SUNDAY. DEPENDING ON THE ACTUAL STRENGTHEN OF THIS SYSTEM...IT COULD
RESULT IN A PERIOD OF STRONG NORTHERLY WINDS DOWN THE LAKE.
HOWEVER...UNCERTAINTY IS STILL SOMEWHAT HIGH WITH THIS SYSTEM.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...6 PM WEDNESDAY TO NOON
THURSDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...6 PM
WEDNESDAY TO NOON THURSDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM
WEDNESDAY.
HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ567-LMZ669-LMZ671-
LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-
LMZ876-LMZ878 UNTIL 9 PM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO BURNS HARBOR UNTIL
9 AM THURSDAY.
GALE WARNING...NEARSHORE BURNS HARBOR TO MICHIGAN CITY IN UNTIL 6 PM WEDNESDAY.
&&
$$
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
1147 AM CST Wed Feb 18 2015
.UPDATE...
ISSUED AT 1031 AM CST WED FEB 18 2015
Bitterly cold airmass settling into the Midwest as a low pressure
system moves out through the eastern Great Lakes. Pressure
gradient is increasing across the region as high pressure from the
Plains edges eastward. Increased pressure gradient resulting in
brisk NW sustained winds and 28-30kt winds aloft mixing down into
the higher gusts this morning. Deep synoptic trof over the Central
and Eastern CONUS this morning maintaining some cyclonic flow
aloft and a little bit of associated instability keeping some cu
development/possible flurries over the region for the afternoon.
No major changes anticipated in the forecast at this point but
will be making some small adjustments to freshen for the current
trends in a brief clearing of the sky and temps.
&&
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1138 AM CST WED FEB 18 2015
Blustery and flurries through the afternoon with northwesterly
winds gusting to 30kts. Although many of the sites are currently
reporting VFR cigs, the MVFR cigs below 3kft are spreading as the
clouds develop. Have opted to start the TAF pd in MVFR as it will
be quickly. Same clouds present a bit of an issue for the
overnight hours. Whether or not that moisture is going to get
trapped as the sun sets this afternoon. Cold arctic high pressure
moving in with signif dwpt drops at the sfc...but lower dwpts not
here just yet. DVN sounding inversion this morning close to the
height of the developing deck. Instead of choosing for SKC or
OVC...have placed the cloud deck closer to the trof axis, and
deeper into the higher dwpts in CMI...clear for PIA to get out
from under todays clouds...and scattering down the middle.
Transition zone between up under the cloud deck and the clear
skies may present a narrow vis reduction as well if the dry air
advection slows too much after sunset.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...HJS
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1147 AM CST Wed Feb 18 2015
.UPDATE...
ISSUED AT 1031 AM CST WED FEB 18 2015
Bitterly cold airmass settling into the Midwest as a low pressure
system moves out through the eastern Great Lakes. Pressure
gradient is increasing across the region as high pressure from the
Plains edges eastward. Increased pressure gradient resulting in
brisk NW sustained winds and 28-30kt winds aloft mixing down into
the higher gusts this morning. Deep synoptic trof over the Central
and Eastern CONUS this morning maintaining some cyclonic flow
aloft and a little bit of associated instability keeping some cu
development/possible flurries over the region for the afternoon.
No major changes anticipated in the forecast at this point but
will be making some small adjustments to freshen for the current
trends in a brief clearing of the sky and temps.
&&
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1138 AM CST WED FEB 18 2015
Blustery and flurries through the afternoon with northwesterly
winds gusting to 30kts. Although many of the sites are currently
reporting VFR cigs, the MVFR cigs below 3kft are spreading as the
clouds develop. Have opted to start the TAF pd in MVFR as it will
be quickly. Same clouds present a bit of an issue for the
overnight hours. Whether or not that moisture is going to get
trapped as the sun sets this afternoon. Cold arctic high pressure
moving in with signif dwpt drops at the sfc...but lower dwpts not
here just yet. DVN sounding inversion this morning close to the
height of the developing deck. Instead of choosing for SKC or
OVC...have placed the cloud deck closer to the trof axis, and
deeper into the higher dwpts in CMI...clear for PIA to get out
from under todays clouds...and scattering down the middle.
Transition zone between up under the cloud deck and the clear
skies may present a narrow vis reduction as well if the dry air
advection slows too much after sunset.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...HJS
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1041 AM CST Wed Feb 18 2015
.UPDATE...
ISSUED AT 1031 AM CST WED FEB 18 2015
Bitterly cold airmass settling into the Midwest as a low pressure
system moves out through the eastern Great Lakes. Pressure
gradient is increasing across the region as high pressure from the
Plains edges eastward. Increased pressure gradient resulting in
brisk NW sustained winds and 28-30kt winds aloft mixing down into
the higher gusts this morning. Deep synoptic trof over the Central
and Eastern CONUS this morning maintaining some cyclonic flow
aloft and a little bit of associated instability keeping some cu
development/possible flurries over the region for the afternoon.
No major changes anticipated in the forecast at this point but
will be making some small adjustments to freshen for the current
trends in a brief clearing of the sky and temps.
&&
.SHORT TERM...(Today)
ISSUED AT 329 AM CST WED FEB 18 2015
A compact shortwave that produced accumulating snows in our
southeast counties early this morning will depart to the southeast
by 5 am, leaving 1 to 2 inches of fluffy accumulation in its wake.
Additional lobes of energy in the strong NW flow aloft will likely
trigger flurries across the area today, but little additional
accumulation is expected. Any clearing that develops will likely see
some clouds reform, which could produce light snow in the strong cold
advection regime.
Northwest winds will increase into the 15 to 20 mph range with gusts
to 35 mph at times. That will cause blowing and drifting of the
fluffy snow that fell last night. Travel will be slippery today
across the area as a result.
Temps will struggle to climb much today, with a diurnal swing of
less than 5 degrees in many areas. Daytime highs will likely remain
in the single digits in northern areas and around 10 in the south.
The combo of wind and cold temps will put wind chills into advisory
levels this morning, and possibly through the afternoon as well.
Even if sustained winds don`t increase enough to produce wind chill
advisory criteria in some of our area, the gusts to 30+ mph will
push wind chills much colder from time to time. Therefore, since
bitter cold wind chills were expected tonight and Thursday as well,
and after collaboration with surrounding offices, we decided to
expand our current wind chill advisory for this morning to include
all of our counties and we extended it in time to include tonight
and Thursday morning.
&&
.LONG TERM...(Tonight through Tuesday)
ISSUED AT 329 AM CST WED FEB 18 2015
Wind chill advisory continues tonight through Thu morning across
central and southeast IL for wind chills of 15 to 25 below zero. A
few spots in the north and east will be flirting with wind chill
warning criteria of 25 below zero overnight until mid Thu morning.
Lows tonight in the single digits below zero as 850 temps down to
-25 to -27C. Highs Thu even a bit colder than today, only in the
upper single digits, to near 10F from Springfield sw despite mostly
sunny skies. Arctic high pressure over western Canada drops down
into IL by sunset Thu and this to lighten winds Thu & Thu night.
Another bitter cold night Thu night with lows ranging from 5 above
to 5 below zero with coldest readings in southeast IL and near IN
border.
Arctic high pressure drifts east across the Ohio river valley and
into the mid Atlantic states Friday while increasing warm air
advection and isentropic lift into central IL to develop chances of
light snow especially by Friday afternoon with mostly cloudy skies.
Highs Friday 20-25F with coldest readings in east central IL.
Extended models now showing surface low pressure lifting ne from the
southern plains across the Ohio river this weekend though timing
differences still exist with GFS model slower and linger more
precipitation over IL Sunday. Will stay close to guidance pops this
weekend which increases Sat and Sat night with likely pops in
southeast IL where a mixture of freezing rain, sleet, snow and even
rain occurs Sat and Sat evening. Also added chance of sleet with the
snow Friday night over southeast IL with freezing rain chances south
of highway 50 in southern IL. Storm system will tap into the Gulf of
Mexico and have ample moisture to work with and qpf amounts in
southeast IL are half to 1 inch with far southeast IL near
Lawrenceville over 1 inch. Storm system bears watching with snow
accumulations likely over central IL especially se of the IL river.
Sat has mildest highs in the 30s, then colder air ushers back into
the region early next week.
The Climate Prediction Center (CPC) Day 8-14 Outlook from Feb
25-Mar 3 continues greater than 60% chance of below normal
temperatures across IL. So winter cold looks to continue the next
two weeks.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 600 AM CST WED FEB 18 2015
Shortwave energy aloft will keep clouds/flurries around today.
Cloud heights are generally low VFR, with MVFR clouds and brief
MVFR visibility in light snow around BMI and CMI. HRRR guidance
points toward a lowering of clouds heights in general this
afternoon, with 1500-2500 FT in most areas and scattered flurries.
The bulk of the upper energy should depart to the east by this
evening, leaving clearing skies later tonight.
Northwest winds will increase this morning into the 14-18kt range,
with gusts to 30kt at times today. The strong winds will cause
blowing and drifting of the fluffy snow that fell last night,
creating slippery travel surfaces today. Wind gusts will diminish
tonight as the pressure gradient weakens, but sustained winds will
remain in the 10-15kt range through the evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until Noon CST Thursday FOR ILZ027>031-
036>038-040>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Shimon
LONG TERM...07
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
340 PM EST WED FEB 18 2015
.SYNOPSIS...
ISSUED AT 425 AM EST WED FEB 18 2015
PERIODS OF LAKE EFFECT SNOW...HEAVIEST ACROSS FAR NORTH-CENTRAL
INDIANA AND SOUTHWEST LOWER MICHIGAN...WILL CREATE HAZARDOUS
DRIVING CONDITIONS TODAY...TONIGHT AND THURSDAY. AFTERNOON HIGH
TEMPERATURES WILL ONLY REACH THE TEENS. LOWS TONIGHT WILL RANGE
FROM A FEW DEGREES ABOVE ZERO NEAR LAKE MICHIGAN TO ZERO TO TEN
BELOW ZERO AWAY FROM THE LAKE. DANGEROUS WIND CHILLS ARE ALSO
EXPECTED BY LATER TODAY THROUGH FRIDAY MORNING...GENERALLY
RANGING BETWEEN 10 BELOW AND 25 BELOW ZERO. SNOW CHANCES RETURN
TO THE ENTIRE AREA LATER THIS WEEKEND AS A POTENTIAL WINTER STORM
MOVES INTO THE OHIO VALLEY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 336 PM EST WED FEB 18 2015
ELONGATED SFC TROUGH LEFTOVER FM EARLIER MESOVORT THAT DISSIPATED
THROUGH WRN LWR MI STILL SUSTAINING AN INTENSE BAND OF LK EFFECT
SNOW FM SERN LAGRANGE NWWD THROUGH WRN ST JOE. WWD OF THIS PRIMARY
BAND...LESS INTENSE MULTIBANDS CONT TO DVLP W/SOMEWHAT GREATER
ORGANIZATION NOTED ACRS WRN CASS SEWD THROUGH ERN ELKHART.
OUTSIDE THESE AREAS...DRY ENTRAINMENT TAKING ITS TOLL ON DIURNAL
ENHANCEMENT TRYING TO DVLP SOUTH OF HIGHWAY 30 AND SUSPECT LTL IF
ANYTHING WILL MATERIALIZE NOW PRIOR TO SUNSET AND LOSS OF LIMITED
DIURNAL HEATING.
OF NOTE GOING FWD IS XPCD REDVLPMNT OF PRIMARY SINGLE BAND AS CLD
LYR FLW VEERS OVERNIGHT AND LL THERMAL TROUGH MAXIMIZES. BASED ON
EARLY MORNING DVLPMNT/EVOLUTION AND IN LIGHT OF 12Z NAM/CONCURRENT
LTR RUC TRENDS...ANOTHER INTENSE SINGLE BAND XPCD TO DVLP TWD 06Z
ALG THE ERN SHORELINE OF WRN LWR MI AND THEN SHIFT SWD INTO NW IN BY
DAYBREAK THU BFR STALLING OUT NW-SE NORTH OF THE HIGHWAY 30 CORRIDOR
BFR BREAKING UP TWD THU EVENING. WILL ADJUST HIGHLITES TO ADD A
BUFFER STRIP OF SNOW/BLWG SNOW ADVISORY COUNTIES...KOSCIUSKO EAST
THROUGH STEUBEN/DEKALB TO ALIGN W/SRN EXTENT OF LIGHT SNOW SHOWERS
AND MORE SIG GRADIENT FLW THROUGH 03Z.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 336 PM EST WED FEB 18 2015
...WEEKEND SYSTEM TO BRING POTENTIAL MIXED PRECIPIATION...
FORECAST PERIOD BEGINS WITH DIMINISHING LES AS INITIAL SETUP AT 00Z
FRI WITH 3-4KFT INVERSION HEIGHTS AND DELTA T OF 25-30C AND SLIGHTLY
VEERING NW FLOW OF 290-330 UNDER THE INVERSION WILL QUICKLY
DISSIPATE AS SURFACE RIDGE AXIS SHIFTS EASTWARD OVER THE AREA.
MODELS OFFERING VARYING SOLUTIONS ON TIMING AND PLACEMENT OF SYSTEMS
ARRIVING THIS WEEKEND. WEAK NORTHERN STREAM CLIPPER WILL APPROACH
THE GREAT LAKES REGION FRIDAY AND OFFER LITTLE MORE THAN
SLIGHT/CHANCE POPS DURING THE DAY FRIDAY. SOUTHERN STREAM SYSTEM
WILL THEN MOVE UP INTO THE TN/OH VALLEY ON SATURDAY. MODELS CONTINUE
TO TREND MORE TOWARDS THE NW WITH TRACK OF SFC LOW WITH GEM MOST
AGGRESSIVE ON PRECIP WITH OVER 1.5 INCHES...ECMWF AND GFS LOWER BUT
STILL RESPECTABLE. WITH TRENDS POINTING TOWARD HIGHER CONFIDENCE IN
CHANCES FOR MEASURABLE PRECIP...HAVE INCREASED POPS SUBSTANTIALLY
SATURDAY AFTERNOON AND NIGHT WITH CAT POPS SE SAT NGT. AS FOR PTYPE
AND AMOUNTS...FURTHER NORTH TRACK WILL INTRODUCE GREATER MIX
POTENTIAL SAT AFTN/EVE ESPECIALLY S/SE PORTIONS AS HIGHS MAY CLIMB
ABOVE FREEZING SAT AFTERNOON AND POSSIBLY HOLD INTO THE EVENING.
FOR NOW HAVE WENT WITH RAIN OR SNOW SATURDAY AFTERNOON WITH LIKELY
NEED TO EXPAND INTO PARTS OF SAT NGT IN LATER FORECASTS. COULD
BECOME QUITE MESSY FOR MUCH OF THE WEEKEND SO STAY TUNED FOR LATER
UPDATES.
FEW CHANGES TO PERIODS BEYOND THE WEEKEND WITH EFFECTS OF THE
WEEKEND SYSTEM POSSIBLY DICTATING AMOUNT/SPEED OF COLD AIR RETURN TO
THE REGION AND IMPACTS IN TERMS OF LAKE EFFECT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1237 PM EST WED FEB 18 2015
LK EFFECT SNOW IMPACTING KSBN AND W/APPRECIABLE UPTICK IN GRADIENT FLW
XPC LIFR CONDS TO PERSIST THROUGH THIS AFTN BFR ABATING SOMEWHAT
LT THIS AFTN AND EVENING. HWVR SECONDARY INTENSE SINGLE BAND
DVLPMNT XPCD TO REFOCUS WWD OF CURRENT BAND LT TONIGHT AND CARRY
SWD THROUGH THU AM. HAVE BASICALLY THINGS DOWN W/HEAVY SNOW LIKELY
AT THE TERMINAL ALTHOUGH 18Z FCST TIMING IS LIKELY TOO OPTIMISTIC
AND WILL NEED TO BE BUMPED BACK MORE TWD 09Z.
KFWA ATTM REMAINS OUTSIDE ANY POTENTIAL LK EFFECT IMPACTS. HWVR
INCREASINGLY MOIST AND UNSTABLE BNDRY LYR XPCD ON THU AS LL
THERMAL TROUGH MAXIMIZES AND GREATER CLD LYR VEERING OCCURS OVR
THE LAKE. THIS SHLD RESULT IN A PD OF MVFR OR PERHAPS IFR CONDS AT
KFWA JUST AFT 18Z THU. WILL ADDRESS IN LTR FCSTS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ THURSDAY FOR
INZ007>009-012>018-020-022>027-032>034.
WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ THURSDAY FOR
INZ003>006.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
INZ007>009-016.
MI...WIND CHILL ADVISORY UNTIL NOON EST THURSDAY FOR MIZ080-081.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ079.
WINTER STORM WARNING UNTIL 7 PM EST THURSDAY FOR MIZ077-078.
OH...WIND CHILL ADVISORY UNTIL NOON EST THURSDAY FOR OHZ001-002-004-
005-015-016-024-025.
LM...NONE.
&&
$$
SYNOPSIS...STEINWEDEL
SHORT TERM...T
LONG TERM...FISHER
AVIATION...T
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
1211 PM CST WED FEB 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY
BEFORE GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO
THE REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM
-18C TO -23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY
COLDER. ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING
WITH THE NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE
NORTHEAST NEAR OR SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO
NOT EXPECT MUCH OF A WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF
FOR MAX TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY.
THIS RESULTED IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND
LITTLE CHANGE ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO
REACH WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/18Z
ISSUED AT 1118 AM CST WED FEB 18 2015
HIGH PRESSURE WILL KEEP CONDITIONS PRIMARILY VFR THROUGH PERIOD.
WILL SEE MVFR CEILINGS EARLY IN PERIOD AT EASTERN SITES
KMCW/KALO/KOTM BEFORE PUSHING EAST. NORTHWESTERLY WINDS WILL BE
STRONG AND GUSTY THROUGH 00Z...WITH GUSTS UP TO 30KTS POSSIBLE AT
TIMES. WINDS WILL DECREASE AND BECOME MORE NORTHERLY AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1121 AM CST WED FEB 18 2015
.SHORT TERM /TODAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
ARCTIC FRONT WILL CONTINUE TO PUSH SOUTH AND SHOULD
EXIT THE STATE BY 12Z AT THE LATEST. WELL ADVERTISED COLD SNAP IS
HERE AND THE STRONG CAA LOOKS TO PERSIST THROUGHOUT THE DAY
BEFORE GRADUALLY RELAXING PAST 21Z AS THE SURFACE HIGH BUILDS INTO
THE REGION. MIXING TO AROUND 925 TO 900MB WHERE TEMPS RANGE FROM
-18C TO -23C DEPICTED BY THE HIRES ARW/NMM...WITH THE NMM SLIGHTLY
COLDER. ECMWF IS WARMEST WRT TO MAX TEMPS TODAY DESPITE AGREEING
WITH THE NAM/GFS ON 925MB TEMPS. THE LATEST HRRR KEEPS THE
NORTHEAST NEAR OR SLIGHTLY BELOW ZERO THROUGH 20Z AND CERTAINLY DO
NOT EXPECT MUCH OF A WARMUP B/T 20-00Z. LEANED TOWARD THE RAP/SREF
FOR MAX TEMPS...ESPECIALLY ACROSS THE NORTHEAST TO EAST TODAY.
THIS RESULTED IN SLIGHTLY LOWERING MAX TEMPS IN THE NORTHEAST AND
LITTLE CHANGE ELSEWHERE.
POTENTIAL FOR A FEW AREAS ACROSS THE NORTH FROM MCW TO ALO TO
REACH WIND CHILL WARNING CRITERIA (-30F) FOR A SHORT STINT THIS
MORNING...BUT LOOKS TO BE BORDERLINE AND NOT TO LAST MUCH LONGER
THAN 3 HOURS AND FELT THE CURRENT WIND CHILL ADVISORY WAS SUFFICE.
WIND CHILL ADVISORY CRITERIA IS STILL BEING MET PAST 18Z TODAY AND
MAY NEED TO EXTEND THE ADVISORY ACROSS THE NORTHEAST.
.LONG TERM /TONIGHT THROUGH TUESDAY/...
ISSUED AT 311 AM CST WED FEB 18 2015
MAIN CHALLENGES THROUGH THE PERIOD WILL INCLUDE IMMEDIATE COLD
TEMPERATURES...BRIEF WARMING INTO THE EARLY PORTION OF THE WEEKEND
AND CONTINUATION OF LARGE SCALE H500 ANCHOR LOW THROUGH THE
REMAINDER OF THE EXTENDED WITH A FEW WRINKLES ALONG THE WAY. AS
SURFACE RIDGE AXIS SETTLES INTO THE AREA TONIGHT/EARLY THURSDAY WITH
CLEAR SKIES...TEMPERATURES WILL DROP SIGNIFICANTLY OVER THE
REGION...ESPECIALLY THE COLD PRONE AREAS NEAR US HIGHWAY 20 AND THE
IOWA RIVER VALLEY. HAVE LOWERED MINS THERE TONIGHT WITH EXPECTATION
THAT WITH LINGERING SNOW COVER TEMPS WILL BOTTOM TO NEAR 15 BELOW AT
KALO BY MORNING. DURING THE DAY THURSDAY TEMPERATURES WILL RECOVER
WEST AS WARM AIR ADVECTION INCREASES. MOST OF THE MODELS CONTINUE TO
SHOW A QUICK HIT OF LIGHT SNOW AS THE WARM FRONT PROGRESSES EAST
THURSDAY NIGHT AND FRIDAY. ISENTROPIC LIFT OVER A DEVELOPING
H850/H700 FRONT ALOFT FOCUSES THE LIGHT SNOW JUST EAST OF THE
BOUNDARY. HAVE INCREASED POP TO HIGH CHANCE/LOW LIKELY CAT FOR NOW
WITH ROUGHLY A HALF INCH TO INCH OF LIGHT SNOW DURING THE EVENT.
THOUGH MOST OF THE SNOW WILL FALL OVERNIGHT...TRAVEL MAY BE IMPACTED
FROM I80 EAST FRIDAY MORNING DUE TO A LIGHT DUSTING OF VERY POWDERY
SNOW ON AREA ROADS. INCREASING SOUTH WINDS MAY CAUSE SOME MINOR
BLOWING SNOW FRIDAY MORNING. BY LATE DAY FRIDAY MILDER AIR WILL MOVE
ACROSS THE REGION LIFTING AFTERNOON HIGHS INTO THE MID 20S EAST TO
MID 30S WEST AS H850 TEMPS RECOVER TO -4C EAST TO NEAR 0C SOUTHWEST.
ALSO OF NOTE BY LATE FRIDAY...THE EURO HAS A WAVE OVER THE ROCKIES
DIGGING SOUTH TOWARD THE OK PANHANDLE THEN MOVING EAST. THIS INDUCES
SFC LOW DEVELOPMENT OVER TEXAS WHICH THEN MOVES EAST NORTHEAST. BOTH
THE EURO/GEM ARE TRENDING SOUTH WITH THIS SYSTEM WHILE THE GFS IS
CURRENTLY FARTHER NORTH TAKING THE NORTHERN PRECIPITATION SHIELD
INTO SOUTHERN IOWA. THOUGH SOME UNCERTAINTY REMAINS...THE
PREDOMINANT STREAM THIS SEASON HAS REMAINED THE SOUTHERN STREAM AND
FAVOR THE MORE SOUTHERN SOLUTIONS AT THIS TIME...THAT AND THE
ADVERTISED COLD FRONT THAT WILL MOVE SOUTH OF THE AREA SATURDAY AS
ANOTHER ARCTIC HIGH OVER MANITOBA CANADA SLOWLY DRIFTS SOUTH INTO
IOWA BY MONDAY. THIS SHOULD HELP SUPPRESS THE STORM TRACK TO SOUTH
OF THE STATE. THE ADVANCING HIGH WILL RESULT IN MUCH COLDER
CONDITIONS BY SUNDAY NIGHT WITH SUB ZERO LOWS ONCE AGAIN AND HIGHS
RECOVERING ONLY INTO THE UPPER TEENS TO LOWER 20S ON MONDAY. WITH
THE PARENT ANCHOR LOW OVER HUDSON BAY CANADA AND PLENTY OF UPSTREAM
ENERGY... AND CROSS POLAR FLOW...THERE WILL BE YET ANOTHER
VIGOROUS SHORT WAVE CLIPPER WILL RACING SOUTHEAST TOWARD THE
GREAT LAKES TUESDAY. DESPITE SOME TIMING DIFFERENCES IN THE MODELS
WITH THE GFS BEING ITS USUAL QUICK SELF...THE END RESULT WILL
LIKELY BE THE SAME. ANOTHER EXCEPTIONALLY COLD AIRMASS WILL ARRIVE
BY LATE IN THE EXTENDED PERIOD WITH THE LOWEST THICKNESS VALUES
RANGING FROM 486DM TO 492DM OVER WI/MN/MI BY MIDDAY TUESDAY.
THOUGH THE COLDEST AIR LOOKS TO BE JUST EAST OF IOWA...I SUSPECT
DOUBLE DIGIT BELOW ZERO OVERNIGHT LOWS ONCE AGAIN OVER PORTIONS OF
THE FORECAST AREA BY DAY 7 NIGHT IF THE CURRENT PROGS HOLD. BOTTOM
LINE...BETWEEN TODAY AND NEXT TUESDAY WE SHOULD EXPERIENCE A TOTAL
OF 3 ARCTIC INTRUSIONS FROM THE CENTRAL PLAINS AND GREAT
LAKES...EAST ALL THE WAY TO NEW ENGLAND. EXPECT MORE WIND AND
BITTER COLD.
&&
.AVIATION...18/18Z
ISSUED AT 1118 AM CST WED FEB 18 2015
HIGH PRESSURE WILL KEEP CONDITIONS PRIMARILY VFR THROUGH PERIOD.
WILL SEE MVFR CEILINGS EARLY IN PERIOD AT EASTERN SITES
KMCW/KALO/KOTM BEFORE PUSHING EAST. NORTHWESTERLY WINDS WILL BE
STRONG AND GUSTY THROUGH 00Z...WITH GUSTS UP TO 30KTS POSSIBLE AT
TIMES. WINDS WILL DECREASE AND BECOME MORE NORTHERLY AFTER 00Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-
CASS-CERRO GORDO-CLARKE-CRAWFORD-DALLAS-DAVIS-DECATUR-EMMET-
FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
JASPER-KOSSUTH-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-MONROE-PALO
ALTO-POCAHONTAS-POLK-POWESHIEK-RINGGOLD-SAC-STORY-TAMA-TAYLOR-
UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...REV
AVIATION...AWB
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
208 PM EST Wed Feb 18 2015
...Forecast Update...
Issued at 208 PM EST Wed Feb 18 2015
Just did a quick update to upgrade the Wind Chill Advisory to a Wind
Chill Warning for late this afternoon and tonight. Based on the
latest forecast data, overnight wind chill readings are likely to
drop into the -25 to -30 degree range. Updated Winter Weather
Bulletins are out.
Remainder of the forecast remains on track. Plenty of NW to SE
moving bands of snow showers and squalls continue to move across the
region. We expect this activity to continue through sunset then
rapidly diminish. Temperatures remain in the low teens but will
drop into the single digits late this afternoon and evening.
Update issued at 1045 AM EST Wed Feb 18 2015
NW-SE oriented snow squalls continue to move through central and
east-central KY this morning. These squalls are moving off to the
east at 25-30 MPH and will affect the Bluegrass region of central KY
for the remainder of the morning.
Latest runs from the HRRR suggest that more NW-SE oriented finger
bands of snow squalls are expected to redevelop across the region.
Based on the last few runs of the HRRR, it appears that the best
coverage of snow showers/squalls would generally be along and east
of the I-65 corridor. Based on those trends, have increased PoPs and
cloud cover east of I-65 for the afternoon hours. While we will be
running high chance PoPs, it really is more based on expected
coverage. Some areas will see snow showers, others may escape with
only flurries. Within these squalls an additional 1 to perhaps as
much as 2 inches could be seen...especially if a band sets up over a
particular area.
We will keep the Winter Weather Advisory going through the afternoon
for the entire area. Temperatures will continue to fall with
readings mainly in the teens with a fall into single digits by the
evening. With the loss of heating and the trough axis aloft heading
to the east, we expect to see the snow shower/squall activity drop
off rapidly after sunset.
Based on upstream observations, it appears we will go more clear
tonight resulting in temperatures falling well below zero
overnight. Current thinking is that our current forecast minimums
are too warm and that further downward adjustments will be needed.
We will continue to look at the full 12Z guidance before making
major adjustments. In addition, current wind forecasts combined
with colder temperatures may necessitate an upgrade of the wind
chill advisory to a wind chill warning. Will be collaborating with
surrounding offices on this during the afternoon.
Update issued at 938 AM EST Wed Feb 18 2015
Pretty decent snow squall moving eastward through the central part
of the forecast area. The squall is just west of US 27/127 and will
continue to move east at 25-30 MPH. The squall is producing heavy
snow, winds up to 25-30 MPH and reducing visibilities down below 1/4
of a mile. This will impact the Frankfort and Lexington areas in
the next hour. One half to one inch of snowfall is expected with
this squall. Although, it is very difficult to measure the exact
snowfall as the 25-30 MPH winds are really whipping the snow around.
Update issued at 819 AM EST Wed Feb 18 2015
Surface cold front is currently pushing through the I-65 corridor at
the moment and will continue eastward toward the I-75 corridor this
morning. Current tracking suggests that it will clear our forecast
area by 16-17Z. A few snow showers will trail behind the cold
front, but the bulk of snow will still occur out ahead of the front.
Northwest winds of 15-20 MPH with gusts up to 25 MPH will be common
as we continue into the morning hours. We will see a brief lull in
the snow shower activity, but we expect snow showers and heavier
snow squalls to redevelop this afternoon. These squalls will have
the potential to lay down some additional localized accumulations.
Temperatures will continue to fall through the afternoon, so the
warmest temperatures of the day have already occurred.
.SHORT TERM (Now through Thursday)...
Issued at 318 AM EST Wed Feb 18 2015
...Bitter cold temperatures and wind chills...
An area of light to moderate snow will cross the region early this
morning, exiting to the east by late morning. Accumulations around
an inch to as much as 2 inches still look reasonable, so will keep
the Winter Weather Advisory going.
A cold front crossing the area early this morning will usher in
gusty west winds and very cold air. Winds of 10 to 20 mph will gust
to 20 to 30 mph. The CAA behind the front will cause temperatures
to fall this afternoon. The combination of very cold temperatures
and brisk winds will lead to wind chills at or below -10 by mid
afternoon, so will hoist a Wind Chill Advisory.
This afternoon we`ll have strong cold air advection aloft and partly
to mostly cloudy skies, leading to weak instability. We`ll have
high RH below 700 hPa, much of it in temperatures very conducive to
snowflake growth. Also, we`ll be beneath upper level cyclonic flow
and SPC`s snow squall parameter is expected to be around 3, which is
very supportive of snow showers. As a result, scattered snow
showers are expected throughout the area this afternoon, and could
put down additional local accumulations. In addition to the snow
showers, those biting winds on top of the new fluffy snow from this
morning (plus the pre-existing snow pack from Monday) will lead to
blowing snow, especially in rural areas. As a result, will keep the
Winter Weather Advisory going through the afternoon for the
combination of falling snow, blowing snow, and dangerous wind chills.
Any snow showers this afternoon should end quickly this evening as
the sun sets and the upper trof axis is well east of here.
With the deep snowpack in place, reinforced by new snow this morning
and possibly this afternoon, temperatures tonight will be extremely
cold. Kept the forecast we`ve had going for the past few days, and,
after seeing some of the amazing numbers on the Kentucky Mesonet for
yesterday morning`s lows, ran a tool we have that takes local cold
spots into account when determining the low temperature forecast.
The tool gave lows as low as -20 in a few locations for Thursday
morning. Decided to temper the numbers just a bit, keeping them in
the -9 to -17 range (there may be scattered clouds in the area, plus
some wind), but suffice to say that it will be a cold night. Winds
near 10 mph will continue to give us extremely cold wind chills,
possibly meeting warning criteria. If widespread warning criteria
look likely, the Wind Chill Advisory may need to be upgraded.
Tomorrow the arctic high that is giving us all this cold air will
move right into the Ohio Valley. For now we will aim for highs in
the single digits, though some locations...especially those in the
Blue Grass that have the deepest snow cover...may be lucky to get
above zero. West winds of 10 to 15 mph will continue to provide
advisory level wind chills...possibly warning level in the morning.
For the past couple of days the GFS has been advertising slightly
deeper moisture than most other models Thursday afternoon, and has
been consistent in generating some extremely light QPF. As a nod to
the model`s insistence, will add in some scattered flurries Thursday
afternoon over the Blue Grass. It doesn`t take much to squeeze a
few snowflakes out of air this cold.
For now, will allow the Wind Chill Advisory to expire Thursday
evening since winds Thursday night go nearly calm. Nevertheless,
even a tiny breeze will result in very cold wind chills in this
frigid air. Future shifts will continue to assess if an advisory
will be needed for Thursday night into Friday.
Thanks to IND, JKL, and ILN for coord.
.LONG TERM (Thursday night through Tuesday)...
Issued at 300 AM EST Wed Feb 18 2015
...Record Cold Friday Morning Then Potential Weekend Wintry Mess...
Thursday night is shaping up to be the second consecutive night of
record cold for central Kentucky and southern Indiana as a very
anomalous Arctic airmass takes over the Ohio Valley. Synoptically,
the deep upper trough will be anchored over the Great Lakes and
Northeast US while the Arctic high advances from the central Plains
eastward, centering itself over eastern Kentucky by 12z Friday
morning. 850 mb temperatures are expected to be in the -22 to -25C
range, which would be a record for ILN upper air sounding
climatology. NAEFS standardized anomalies consistently show -4 to
-5SD from Wed 18z to Fri 18z, an impressive 48 hour stretch. Helping
to reach these extreme temperatures will be the recent snowpack and
lighter winds and overall mostly clear skies. However, high level
clouds are likely to spread east across the area after midnight,
which could limit the radiational cooling, especially west of I-65.
Overall though, confidence is high that we`ll see lows -10 to -15F
with isolated -20F readings not out of the question for the rural,
typical cold spots of central/eastern Kentucky. Given these extreme
low temperatures, although winds are expected to be less than 10
mph, even light winds will create dangerous wind chills of -20 to
-25 overnight into Friday morning.
Weekend Storm System:
A wintry mix mess is looking likely for much of the region beginning
Friday late afternoon through Saturday. The upper level pattern will
transition to zonal to slightly southwesterly as a western CONUS
trough digs. Pieces of energy will eject out into the southern
Plains resulting in a surface low developing across northern Texas
by Friday evening.
Increasing moist southerly flow ahead of the surface low and
increasing isentropic lift should lead to precipitation breaking out
across Tennessee and southern Kentucky as early as mid afternoon.
Thermal profiles suggest this would be all snow and could produce
quick minor accumulations Friday late afternoon, possibly during the
afternoon commute for areas along the KY/TN border.
During the evening hours, the surface low begins to intensify and
lift toward the region. Precipitation will increase and spread
northward. A low-level jet between 700 and 900 mb will bring a warm
nose of air northward during the evening hours, expected to reach
north central Kentucky by late evening or early overnight. Right now
soundings show this warm layer being on the order of +1 to +3C
during the overnight hours, then steadily increasing Saturday
morning. North of the KY parkways, precipitation could remain as
snow for several hours before mixing with sleet then going over to a
period of freezing rain early Saturday morning. After sunrise
Saturday, most of the area is expected to be near to slightly above
freezing. The exception is across southern Indiana where
temperatures may remain cold enough to support more of a wintry mix
during the morning hours Saturday.
Saturday afternoon through Saturday night the surface low tracks
through Kentucky and precipitation is expected to continue as mainly
rain as the low levels should be sufficiently warm. Precipitation
begins to exit late Saturday night or Sunday morning, which could be
a rain/snow to snow changeover as colder air wraps behind the
system.
Model Preferences / Trends:
A time-trend analysis has shown slight warming in the thermal
profiles over the last 4 cycles, though nothing too significant at
this point. Additionally, the models seem to be a bit more amplified
and slower compared to the past runs. It is noted that the GEM was a
fast outlier while the GFS was similarly on the slower side of the
spread. The forecast was weighted toward the 18.00z ECMWF which
seems to be a good compromise at this point given the large model
spread in timing. The 18.00z guidance as a whole trended back toward
a stronger surface system, which would likely bring warmer air
northward into the region. Overall, confidence in storm track and
timing is average.
Sensible Weather and Impacts:
Overall, a wintry mess is looking more likely across the area Friday
afternoon through Saturday afternoon. The initial snow could
accumulate around 2 inches across the area before changing over to a
wintry mix of sleet and freezing rain. We`ll have to watch for ice
accumulations across southern into central Kentucky where it could
total up to 0.1", causing additional impacts. If the low level
temperatures end up colder or climb slower than forecast, then there
would be a longer period of freezing rain. Something to watch. Then
finally we`ll deal with the liquid part of the event, which is
expected to be on the order of 0.5" or more. On top of a frozen
ground and new snow/sleet/freezing rain, this may cause some
localized hydrology issues for area creeks and streams.
Finally, despite surface temperatures warming above freezing
Saturday, road temperatures will be much slower to respond given the
recent cold snap this week. This could result in additional icy and
slick roadways, or at least further into the day Saturday.
Sunday - Tuesday:
In the wake of the weekend system, a reinforcing shot of Arctic air
is advertised by the 18.00z deterministic and ensemble guidance.
This supports a continuation of below normal temperatures with
northwest flow aloft. A model consensus of highs in the upper 20s to
mid 30s and overnight lows in the teens looks reasonable at this
time.
&&
.AVIATION (18Z TAF Update)...
Issued at 1208 PM EST Wed Feb 18 2015
Surface cold front has passed through the region and in its wake we
have numerous snow showers and snow squalls mainly out in central
Kentucky. Latest high resolution guidance suggests that more snow
showers and squalls will develop later this afternoon. Its
difficult to pinpoint if any particular squall would affect the
airports. For now plan on keeping light snow and blowing snow in at
KSDF and KLEX through the afternoon and snow showers within the
vicinity down at KBWG. Surface winds this afternoon will be out of
the northwest (290 deg mainly) with sustained speeds of 12-15kts
and gusts of around 24-27kts. The blowing snow may result in some
MVFR vsbys at times. Ceilings are generally expected to remain in
the MVFR range, but most likely will see it fluctuate between
MVFR/VFR.
After 19/00Z, we should see marked improvement at the terminals as
the snow shower activity ends. We expect mostly clear skies to
develop, though the models are trying to hold on to some low-level
moisture across the Bluegrass region overnight which may result in a
low cloud deck hanging around. Surface winds will remain elevated
this evening but are expected to slacken toward Thursday morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL WARNING until Noon EST /11 AM CST/ Thursday FOR
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL ADVISORY from Noon EST /11 AM CST/ Thursday to 7 AM
EST /6 AM CST/ Friday FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
IN...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR INZ076>079-083-084-089>092.
WIND CHILL WARNING until Noon EST /11 AM CST/ Thursday FOR
INZ076>079-083-084-089>092.
WIND CHILL ADVISORY from Noon EST /11 AM CST/ Thursday to 7 AM
EST /6 AM CST/ Friday FOR INZ076>079-083-084-089>092.
&&
$$
Update.........MJ
Short Term.....13
Long Term......ZBT
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1209 PM EST Wed Feb 18 2015
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1045 AM EST Wed Feb 18 2015
NW-SE oriented snow squalls continue to move through central and
east-central KY this morning. These squalls are moving off to the
east at 25-30 MPH and will affect the Bluegrass region of central KY
for the remainder of the morning.
Latest runs from the HRRR suggest that more NW-SE oriented finger
bands of snow squalls are expected to redevelop across the region.
Based on the last few runs of the HRRR, it appears that the best
coverage of snow showers/squalls would generally be along and east
of the I-65 corridor. Based on those trends, have increased PoPs and
cloud cover east of I-65 for the afternoon hours. While we will be
running high chance PoPs, it really is more based on expected
coverage. Some areas will see snow showers, others may escape with
only flurries. Within these squalls an additional 1 to perhaps as
much as 2 inches could be seen...especially if a band sets up over a
particular area.
We will keep the Winter Weather Advisory going through the afternoon
for the entire area. Temperatures will continue to fall with
readings mainly in the teens with a fall into single digits by the
evening. With the loss of heating and the trough axis aloft heading
to the east, we expect to see the snow shower/squall activity drop
off rapidly after sunset.
Based on upstream observations, it appears we will go more clear
tonight resulting in temperatures falling well below zero
overnight. Current thinking is that our current forecast minimums
are too warm and that further downward adjustments will be needed.
We will continue to look at the full 12Z guidance before making
major adjustments. In addition, current wind forecasts combined
with colder temperatures may necessitate an upgrade of the wind
chill advisory to a wind chill warning. Will be collaborating with
surrounding offices on this during the afternoon.
Update issued at 938 AM EST Wed Feb 18 2015
Pretty decent snow squall moving eastward through the central part
of the forecast area. The squall is just west of US 27/127 and will
continue to move east at 25-30 MPH. The squall is producing heavy
snow, winds up to 25-30 MPH and reducing visibilities down below 1/4
of a mile. This will impact the Frankfort and Lexington areas in
the next hour. One half to one inch of snowfall is expected with
this squall. Although, it is very difficult to measure the exact
snowfall as the 25-30 MPH winds are really whipping the snow around.
Update issued at 819 AM EST Wed Feb 18 2015
Surface cold front is currently pushing through the I-65 corridor at
the moment and will continue eastward toward the I-75 corridor this
morning. Current tracking suggests that it will clear our forecast
area by 16-17Z. A few snow showers will trail behind the cold
front, but the bulk of snow will still occur out ahead of the front.
Northwest winds of 15-20 MPH with gusts up to 25 MPH will be common
as we continue into the morning hours. We will see a brief lull in
the snow shower activity, but we expect snow showers and heavier
snow squalls to redevelop this afternoon. These squalls will have
the potential to lay down some additional localized accumulations.
Temperatures will continue to fall through the afternoon, so the
warmest temperatures of the day have already occurred.
.SHORT TERM (Now through Thursday)...
Issued at 318 AM EST Wed Feb 18 2015
...Bitter cold temperatures and wind chills...
An area of light to moderate snow will cross the region early this
morning, exiting to the east by late morning. Accumulations around
an inch to as much as 2 inches still look reasonable, so will keep
the Winter Weather Advisory going.
A cold front crossing the area early this morning will usher in
gusty west winds and very cold air. Winds of 10 to 20 mph will gust
to 20 to 30 mph. The CAA behind the front will cause temperatures
to fall this afternoon. The combination of very cold temperatures
and brisk winds will lead to wind chills at or below -10 by mid
afternoon, so will hoist a Wind Chill Advisory.
This afternoon we`ll have strong cold air advection aloft and partly
to mostly cloudy skies, leading to weak instability. We`ll have
high RH below 700 hPa, much of it in temperatures very conducive to
snowflake growth. Also, we`ll be beneath upper level cyclonic flow
and SPC`s snow squall parameter is expected to be around 3, which is
very supportive of snow showers. As a result, scattered snow
showers are expected throughout the area this afternoon, and could
put down additional local accumulations. In addition to the snow
showers, those biting winds on top of the new fluffy snow from this
morning (plus the pre-existing snow pack from Monday) will lead to
blowing snow, especially in rural areas. As a result, will keep the
Winter Weather Advisory going through the afternoon for the
combination of falling snow, blowing snow, and dangerous wind chills.
Any snow showers this afternoon should end quickly this evening as
the sun sets and the upper trof axis is well east of here.
With the deep snowpack in place, reinforced by new snow this morning
and possibly this afternoon, temperatures tonight will be extremely
cold. Kept the forecast we`ve had going for the past few days, and,
after seeing some of the amazing numbers on the Kentucky Mesonet for
yesterday morning`s lows, ran a tool we have that takes local cold
spots into account when determining the low temperature forecast.
The tool gave lows as low as -20 in a few locations for Thursday
morning. Decided to temper the numbers just a bit, keeping them in
the -9 to -17 range (there may be scattered clouds in the area, plus
some wind), but suffice to say that it will be a cold night. Winds
near 10 mph will continue to give us extremely cold wind chills,
possibly meeting warning criteria. If widespread warning criteria
look likely, the Wind Chill Advisory may need to be upgraded.
Tomorrow the arctic high that is giving us all this cold air will
move right into the Ohio Valley. For now we will aim for highs in
the single digits, though some locations...especially those in the
Blue Grass that have the deepest snow cover...may be lucky to get
above zero. West winds of 10 to 15 mph will continue to provide
advisory level wind chills...possibly warning level in the morning.
For the past couple of days the GFS has been advertising slightly
deeper moisture than most other models Thursday afternoon, and has
been consistent in generating some extremely light QPF. As a nod to
the model`s insistence, will add in some scattered flurries Thursday
afternoon over the Blue Grass. It doesn`t take much to squeeze a
few snowflakes out of air this cold.
For now, will allow the Wind Chill Advisory to expire Thursday
evening since winds Thursday night go nearly calm. Nevertheless,
even a tiny breeze will result in very cold wind chills in this
frigid air. Future shifts will continue to assess if an advisory
will be needed for Thursday night into Friday.
Thanks to IND, JKL, and ILN for coord.
.LONG TERM (Thursday night through Tuesday)...
Issued at 300 AM EST Wed Feb 18 2015
...Record Cold Friday Morning Then Potential Weekend Wintry Mess...
Thursday night is shaping up to be the second consecutive night of
record cold for central Kentucky and southern Indiana as a very
anomalous Arctic airmass takes over the Ohio Valley. Synoptically,
the deep upper trough will be anchored over the Great Lakes and
Northeast US while the Arctic high advances from the central Plains
eastward, centering itself over eastern Kentucky by 12z Friday
morning. 850 mb temperatures are expected to be in the -22 to -25C
range, which would be a record for ILN upper air sounding
climatology. NAEFS standardized anomalies consistently show -4 to
-5SD from Wed 18z to Fri 18z, an impressive 48 hour stretch. Helping
to reach these extreme temperatures will be the recent snowpack and
lighter winds and overall mostly clear skies. However, high level
clouds are likely to spread east across the area after midnight,
which could limit the radiational cooling, especially west of I-65.
Overall though, confidence is high that we`ll see lows -10 to -15F
with isolated -20F readings not out of the question for the rural,
typical cold spots of central/eastern Kentucky. Given these extreme
low temperatures, although winds are expected to be less than 10
mph, even light winds will create dangerous wind chills of -20 to
-25 overnight into Friday morning.
Weekend Storm System:
A wintry mix mess is looking likely for much of the region beginning
Friday late afternoon through Saturday. The upper level pattern will
transition to zonal to slightly southwesterly as a western CONUS
trough digs. Pieces of energy will eject out into the southern
Plains resulting in a surface low developing across northern Texas
by Friday evening.
Increasing moist southerly flow ahead of the surface low and
increasing isentropic lift should lead to precipitation breaking out
across Tennessee and southern Kentucky as early as mid afternoon.
Thermal profiles suggest this would be all snow and could produce
quick minor accumulations Friday late afternoon, possibly during the
afternoon commute for areas along the KY/TN border.
During the evening hours, the surface low begins to intensify and
lift toward the region. Precipitation will increase and spread
northward. A low-level jet between 700 and 900 mb will bring a warm
nose of air northward during the evening hours, expected to reach
north central Kentucky by late evening or early overnight. Right now
soundings show this warm layer being on the order of +1 to +3C
during the overnight hours, then steadily increasing Saturday
morning. North of the KY parkways, precipitation could remain as
snow for several hours before mixing with sleet then going over to a
period of freezing rain early Saturday morning. After sunrise
Saturday, most of the area is expected to be near to slightly above
freezing. The exception is across southern Indiana where
temperatures may remain cold enough to support more of a wintry mix
during the morning hours Saturday.
Saturday afternoon through Saturday night the surface low tracks
through Kentucky and precipitation is expected to continue as mainly
rain as the low levels should be sufficiently warm. Precipitation
begins to exit late Saturday night or Sunday morning, which could be
a rain/snow to snow changeover as colder air wraps behind the
system.
Model Preferences / Trends:
A time-trend analysis has shown slight warming in the thermal
profiles over the last 4 cycles, though nothing too significant at
this point. Additionally, the models seem to be a bit more amplified
and slower compared to the past runs. It is noted that the GEM was a
fast outlier while the GFS was similarly on the slower side of the
spread. The forecast was weighted toward the 18.00z ECMWF which
seems to be a good compromise at this point given the large model
spread in timing. The 18.00z guidance as a whole trended back toward
a stronger surface system, which would likely bring warmer air
northward into the region. Overall, confidence in storm track and
timing is average.
Sensible Weather and Impacts:
Overall, a wintry mess is looking more likely across the area Friday
afternoon through Saturday afternoon. The initial snow could
accumulate around 2 inches across the area before changing over to a
wintry mix of sleet and freezing rain. We`ll have to watch for ice
accumulations across southern into central Kentucky where it could
total up to 0.1", causing additional impacts. If the low level
temperatures end up colder or climb slower than forecast, then there
would be a longer period of freezing rain. Something to watch. Then
finally we`ll deal with the liquid part of the event, which is
expected to be on the order of 0.5" or more. On top of a frozen
ground and new snow/sleet/freezing rain, this may cause some
localized hydrology issues for area creeks and streams.
Finally, despite surface temperatures warming above freezing
Saturday, road temperatures will be much slower to respond given the
recent cold snap this week. This could result in additional icy and
slick roadways, or at least further into the day Saturday.
Sunday - Tuesday:
In the wake of the weekend system, a reinforcing shot of Arctic air
is advertised by the 18.00z deterministic and ensemble guidance.
This supports a continuation of below normal temperatures with
northwest flow aloft. A model consensus of highs in the upper 20s to
mid 30s and overnight lows in the teens looks reasonable at this
time.
&&
.AVIATION (18Z TAF Update)...
Issued at 1208 PM EST Wed Feb 18 2015
Surface cold front has passed through the region and in its wake we
have numerous snow showers and snow squalls mainly out in central
Kentucky. Latest high resolution guidance suggests that more snow
showers and squalls will develop later this afternoon. Its
difficult to pinpoint if any particular squall would affect the
airports. For now plan on keeping light snow and blowing snow in at
KSDF and KLEX through the afternoon and snow showers within the
vicinity down at KBWG. Surface winds this afternoon will be out of
the northwest (290 deg mainly) with sustained speeds of 12-15kts
and gusts of around 24-27kts. The blowing snow may result in some
MVFR vsbys at times. Ceilings are generally expected to remain in
the MVFR range, but most likely will see it fluctuate between
MVFR/VFR.
After 19/00Z, we should see marked improvement at the terminals as
the snow shower activity ends. We expect mostly clear skies to
develop, though the models are trying to hold on to some low-level
moisture across the Bluegrass region overnight which may result in a
low cloud deck hanging around. Surface winds will remain elevated
this evening but are expected to slacken toward Thursday morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR KYZ023>043-045>049-053>057-061>067-070>078-081-082.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR KYZ023>043-045>049-053>057-
061>067-070>078-081-082.
IN...WINTER WEATHER ADVISORY until 7 PM EST /6 PM CST/ this evening
FOR INZ076>079-083-084-089>092.
WIND CHILL ADVISORY from 4 PM EST /3 PM CST/ this afternoon to 7
PM EST /6 PM CST/ Thursday FOR INZ076>079-083-084-089>092.
&&
$$
Update.........MJ
Short Term.....13
Long Term......ZBT
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
411 PM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS
EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT
THROUGH THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY
COLD TEMPERATURES.
&&
.NEAR TERM/TONIGHT/...
AS OF 341 PM WEDNESDAY...
...A WINTER WEATHER ADVISORY FOR BLACK ICE WILL BE ISSUED OVER THE
NORTHWESTERN AND NORTHERN PIEDMONT AND COASTAL PLAIN FOR TONIGHT...
...WIND CHILL ADVISORIES IN EFFECT FOR DANGEROUS LIFE THREATENING
WIND CHILLS TONIGHT THROUGH FRIDAY MORNING....
A WINTER WEATHER ADVISORY WILL BE ISSUED FOR A GOOD PORTION OF THE
PIEDMONT... ROUGHLY ALONG THE I-40/85 CORRIDOR REGION FROM THE TRIAD
TO THE TRIANGLE... THEN THE COASTAL PLAIN I-95 CORRIDOR (GOLDSBORO
NORTHWARD TO THE VA BORDER). THIS ADVISORY WILL BE FOR AREAS THAT
STILL HAVE SIGNIFICANT ICE THAT WILL REFREEZE QUICKLY THIS EVENING.
ANY MELTWATER THAT IS RUNNING ACROSS ANY SURFACES EARLY THIS
EVENING WILL FLASH FREEZE. THIS INCLUDES PARKING LOTS... SIDE
WALKS... STREETS... AND ROADS. MANY OF THE URBAN NEIGHBORHOODS OF
THE PIEDMONT STILL HAVE SIGNIFICANT ICE COVER ON THE STREETS/ROADS
THAT ARE PROTECTED FROM THE SUN. EVAPORATION IN THE EXTREME COLD DRY
AIR SHOULD HELP DRY UP MOST BLACK ICE BEFORE 900 AM THURSDAY WHEN
THE ADVISORY WILL END.
NOW TO THE ACTUAL WEATHER FALLING FROM THE SKY...
A BURST OF SNOW OR BRIEF SNOW SHOWERS WILL MOVE QUICKLY FROM
WEST TO EAST ACROSS THE REGION BETWEEN 300 AND 700 PM AND EXITING
THE NE ZONES AROUND 700 PM. ALTHOUGH THE SNOW SHOWERS WILL LAST LESS
THAN AN HOUR A QUICK DUSTING OR COATING MAY RESULT GIVEN THE
CONVECTIVE NATURE OF THE REFLECTIVITY RETURNS CURRENTLY PRODUCING
LESS THAN 0.3 OF AN INCH OF SNOW (PER REPORTS FROM THE TRIAD
REGION). THESE SNOW SHOWERS WILL QUICKLY COOL THE SURFACE
TEMPERATURES DUE TO EVAPORATIVE COOLING DOWN TO FREEZING.
THIS MAY LEAD TO A FEW SLICK SPOTS (NEW SLICK SPOTS) MAINLY ON
ELEVATED SURFACES. MOST OF THIS CONCERN WILL REMAIN NORTH AND
WEST OF FAYETTEVILLE AND GOLDSBORO... ALTHOUGH A BRIEF FLURRY IS
POSSIBLE THERE AS WELL.
AS FOR THE COLD WAVE... THE ACTUAL ARCTIC FRONT WAS PUSHING INTO THE
FOOTHILLS AS OF MID AFTERNOON. THE LEADING EDGE WILL SURGE EAST
ACROSS THE REGION EARLY TO MID EVENING. FORCING OUT AHEAD OF THE
FRONT HAS LED TO THE BANDS OF CONVECTIVE SNOW SHOWERS THAT WILL
AFFECT THE REGION THROUGH EARLY EVENING... WITH ONLY A FEW FLURRIES
EXPECTED BEHIND THE FRONT. WIND GUSTS TO 45 MPH WILL BE LIKELY
WITH THE SNOW SHOWERS AND THE PASSAGE OF THE FRONT. THE ARCTIC AIR
IS LAGGING THE FRONT BY A FEW HOURS BUT THE BOTTOM WILL BEGIN TO
FALL OUT AS THE EVENING GOES ON.
WE EXPECT THAT THE MOS GUIDANCE TEMPERATURES WILL NOT BE COLD ENOUGH
WITH OUR LOWS TONIGHT AND WITH HIGHS ON THURSDAY. LOWS BY DAYBREAK
SHOULD BE 5-10 IN THE NW RANGING TO AROUND 15 IN FAYETTEVILLE AND
GOLDSBORO. COMBINED WITH WINDS 15-25 MPH... MINIMUM WIND CHILLS WILL
RANGE BETWEEN 0 TO NEARLY 15 BELOW DURING MUCH OF THURSDAY MORNING.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 411 PM WEDNESDAY...
...COLD WAVE CONTINUES...
COMBINED WITH WINDS 15-25 MPH... MINIMUM WIND CHILLS WILL RANGE
BETWEEN 0 TO NEARLY 15 BELOW DURING MUCH OF THURSDAY MORNING. WITH
THE CAA CONTINUING ON THURSDAY TEMPERATURES WILL STRUGGLE TO REACH
10-15 NW AND 20 IN THE SE.
THURSDAY NIGHT... WE WILL GO WITH LOWS OF 0-5... WITH SOME AREAS IN
THE NORTH CENTRAL PIEDMONT LIKELY DIPPING TO NEAR 5 BELOW. WIND
CHILL READINGS WILL NOT BE AS BAD... BUT ACTUAL TEMPERATURES WILL
CREATE DANGEROUS TO LIFE THREATENING COLD NONETHELESS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WINTER WEATHER ADVISORY FOR THE PIEDMONT AND COASTAL PLAIN THROUGH
900 AM THURSDAY.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
341 PM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS
EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT
THROUGH THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY
COLD TEMPERATURES.
&&
.NEAR TERM/TONIGHT/...
AS OF 341 PM WEDNESDAY...
...A WINTER WEATHER ADVISORY FOR BLACK ICE WILL BE ISSUED OVER THE
NORTHWESTERN AND NORTHERN PIEDMONT AND COASTAL PLAIN FOR TONIGHT...
...WIND CHILL ADVISORIES IN EFFECT FOR DANGEROUS LIFE THREATENING
WIND CHILLS TONIGHT THROUGH FRIDAY MORNING....
A WINTER WEATHER ADVISORY WILL BE ISSUED FOR A GOOD PORTION OF THE
PIEDMONT... ROUGHLY ALONG THE I-40/85 CORRIDOR REGION FROM THE TRIAD
TO THE TRIANGLE... THEN THE COASTAL PLAIN I-95 CORRIDOR (GOLDSBORO
NORTHWARD TO THE VA BORDER). THIS ADVISORY WILL BE FOR AREAS THAT
STILL HAVE SIGNIFICANT ICE THAT WILL REFREEZE QUICKLY THIS EVENING.
ANY MELTWATER THAT IS RUNNING ACROSS ANY SURFACES EARLY THIS
EVENING WILL FLASH FREEZE. THIS INCLUDES PARKING LOTS... SIDE
WALKS... STREETS... AND ROADS. MANY OF THE URBAN NEIGHBORHOODS OF
THE PIEDMONT STILL HAVE SIGNIFICANT ICE COVER ON THE STREETS/ROADS
THAT ARE PROTECTED FROM THE SUN. EVAPORATION IN THE EXTREME COLD DRY
AIR SHOULD HELP DRY UP MOST BLACK ICE BEFORE 900 AM THURSDAY WHEN
THE ADVISORY WILL END.
NOW TO THE ACTUAL WEATHER FALLING FROM THE SKY...
A BURST OF SNOW OR BRIEF SNOW SHOWERS WILL MOVE QUICKLY FROM
WEST TO EAST ACROSS THE REGION BETWEEN 300 AND 700 PM AND EXITING
THE NE ZONES AROUND 700 PM. ALTHOUGH THE SNOW SHOWERS WILL LAST LESS
THAN AN HOUR A QUICK DUSTING OR COATING MAY RESULT GIVEN THE
CONVECTIVE NATURE OF THE REFLECTIVITY RETURNS CURRENTLY PRODUCING
LESS THAN 0.3 OF AN INCH OF SNOW (PER REPORTS FROM THE TRIAD
REGION). THESE SNOW SHOWERS WILL QUICKLY COOL THE SURFACE
TEMPERATURES DUE TO EVAPORATIVE COOLING DOWN TO FREEZING.
THIS MAY LEAD TO A FEW SLICK SPOTS (NEW SLICK SPOTS) MAINLY ON
ELEVATED SURFACES. MOST OF THIS CONCERN WILL REMAIN NORTH AND
WEST OF FAYETTEVILLE AND GOLDSBORO... ALTHOUGH A BRIEF FLURRY IS
POSSIBLE THERE AS WELL.
AS FOR THE COLD WAVE... THE ACTUAL ARCTIC FRONT WAS PUSHING INTO THE
FOOTHILLS AS OF MID AFTERNOON. THE LEADING EDGE WILL SURGE EAST
ACROSS THE REGION EARLY TO MID EVENING. FORCING OUT AHEAD OF THE
FRONT HAS LED TO THE BANDS OF CONVECTIVE SNOW SHOWERS THAT WILL
AFFECT THE REGION THROUGH EARLY EVENING... WITH ONLY A FEW FLURRIES
EXPECTED BEHIND THE FRONT. WIND GUSTS TO 45 MPH WILL BE LIKELY
WITH THE SNOW SHOWERS AND THE PASSAGE OF THE FRONT. THE ARCTIC AIR
IS LAGGING THE FRONT BY A FEW HOURS BUT THE BOTTOM WILL BEGIN TO
FALL OUT AS THE EVENING GOES ON.
WE EXPECT THAT THE MOS GUIDANCE TEMPERATURES WILL NOT BE COLD ENOUGH
WITH OUR LOWS TONIGHT AND WITH HIGHS ON THURSDAY. LOWS BY DAYBREAK
SHOULD BE 5-10 IN THE NW RANGING TO AROUND 15 IN FAYETTEVILLE AND
GOLDSBORO. COMBINED WITH WINDS 15-25 MPH... MINIMUM WIND CHILLS WILL
RANGE BETWEEN 0 TO NEARLY 15 BELOW DURING MUCH OF THURSDAY MORNING.
WITH THE CAA CONTINUING ON THURSDAY TEMPERATURES WILL STRUGGLE TO
REACH 10-15 NW AND 20 IN THE SE.
THURSDAY NIGHT... WE WILL GO WITH LOWS OF 0-5... WITH SOME AREAS IN
THE NORTH CENTRAL PIEDMONT LIKELY DIPPING TO NEAR 5 BELOW. WIND
CHILL READINGS WILL NOT BE AS BAD... BUT ACTUAL TEMPERATURES
WILL CREATE DANGEROUS TO LIFE THREATENING COLD NONETHELESS.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
WINTER WEATHER ADVISORY FOR THE PIEDMONT AND COASTAL PLAIN THROUGH
900 AM THURSDAY.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1205 PM EST WED FEB 18 2015
.SYNOPSIS...AN ARCTIC COLD FRONT WILL CROSS THE AREA THIS AFTERNOON
THROUGH EARLY EVENING. FRIGID HIGH PRESSURE WILL BUILD OVER THE AREA
THIS EVENING THROUGH EARLY SATURDAY... BRINGING DANGEROUSLY COLD
TEMPERATURES.
&&
.NEAR TERM /TODAY/...
AS OF 1205 PM WEDNESDAY...
...A SPECIAL WEATHER STATEMENT CONTINUES FOR PATCHY RESIDUAL ICE ON
AREA ROADS THIS AFTERNOON... CAUTION ON AREA ROADS IS STILL
ADVISED...
ALSO... A COUPLE OF BANDS OF SNOW SHOWERS WILL BE HANDLED BY SPECIAL
WEATHER STATEMENTS THIS AFTERNOON AS THE WARMER TEMPERATURES SHOULD
PREVENT ANY ADDITIONAL ACCUMULATIONS ON THE ROADS. THE MAIN WEATHER
HAZARD FROM THE SNOW SHOWERS WILL LIKELY BE THE GUSTY WIND TO NEAR
40 MPH AS THE FRONT COMES THROUGH. A QUICK BURST OF LOW VISIBILITIES
WITH THE SNOW SHOWERS WILL OCCUR. THE SHOWERS SHOULD ONLY LAST 15-20
MINUTES AT ANY ONE LOCATION FURTHER LIMITING THE ACCUMULATION
POTENTIAL.
THE TEMPERATURES WERE RISING NICELY OUT AHEAD OF THE ARCTIC FRONT
APPROACHING FROM THE WEST. NOON READINGS WERE ALREADY IN THE MID TO
UPPER 30S. THE ONLY THING HOLDING THE SANDHILLS AND SOUTHERN
PIEDMONT BACK WAS THE RESIDUAL LOW CLOUDS AND FOG... FROM THE
WIDESPREAD DENSE FOG EARLIER TODAY. THESE WILL BE LIFTING OUT TO THE
NE BY EARLY TO MID AFTERNOON. EXPECT TEMPERATURES TO CONTINUE TO
WARM IN ADVANCE OF THE BOUNDARY DRIVEN BY INCREASING SOUTHWESTERLY
FLOW AT 15-20 MPH. HIGHS GENERALLY IN THE LOWER TO MID 40S
EXPECTED... EXCEPT 30S HOLDING ON FROM THE NW PART OF THE TRIAD TO
NEAR ROXBORO. TEMPERATURES WILL BEGIN TO FALL RAPIDLY WITH THE WIND
SHIFT TO THE WNW BEHIND THE FRONT.
THE ACTUAL FRONT WAS PUSHING INTO THE MOUNTAINS AT NOON. THE LEADING
EDGE WAS LOCATED ALONG THE BLUE RIDGE AS NOTED BY THE BANDS OF SNOW
SHOWERS EXTENDING FROM JUST WEST OF HICKORY TO JUST WEST OF MOUNT
AIRY... MOVING EAST. THIS FRONT WILL SURGE OFF THE MOUNTAINS
REACHING THE TRIAD REGION BETWEEN 100 AND 300 PM... THEN THE
TRIANGLE BETWEEN 300 AND 500 PM. THIS IS THE TARGET AREA FOR A BAND
OR TWO OF SNOW SHOWERS THIS AFTERNOON ALONG AND JUST BEHIND THE
FRONT. WINDS WILL BECOME STRONG AND GUSTY AS THE FRONT MOVES
THROUGH. AGAIN... ACCOMPANIED BY A QUICK BURST OF SNOW SHOWERS THAT
ARE NOT EXPECTED TO CAUSE ANY ADDITIONAL TRAVEL HAZARDS.
LOOK FOR THE SPECIAL WEATHER STATEMENTS TO HANDLE THIS ARCTIC FRONT
AND SNOW SHOWERS THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 330 AM WEDNESDAY...
CONFIDENCE IN DANGEROUSLY COLD WEATHER IS INCREASING. BRISK AND
GUSTY WINDS ARE A NEAR CERTAINTY BEHIND THIS ARCTIC FRONT... WITH
THE MOMENTUM OF THE COLD DENSE AIR AND TIGHT MSLP GRADIENT. EXPECT
SUSTAINED WINDS FROM THE NW AROUND 15-25 MPH GUSTING AS HIGH AS 30-
35 MPH TONIGHT. WINDS SHOULD ABATE A BIT THU/THU NIGHT AS THE
INITIAL COLD SURGE WANES... HOWEVER THE MSLP GRADIENT REMAINS TIGHT
ENOUGH TO SUPPORT SUSTAINED NW WINDS OF AROUND 15 MPH GUSTING TO
AROUND 25 MPH THU INTO THU NIGHT. MEANWHILE... RECORD-BUSTING COLD
TEMPERATURES ARE ALSO IMMINENT... WITH MODEL THICKNESSES... BUFR
SOUNDING THERMAL STRUCTURE... STATISTICAL GUIDANCE... AND UPSTREAM
CURRENT CONDITIONS ALL SUPPORTING VERY COLD READINGS. EXPECT LOWS
TONIGHT OF 7-15... HIGHS ONLY 15-23 THU... AND LOWS THU NIGHT OF 1
BELOW TO 7 ABOVE. THESE TEMPS AND WINDS TOGETHER WILL GENERATE SOME
OF THE LOWEST WIND CHILL READINGS WE`VE SEEN IN MANY YEARS...
DROPPING BELOW 0F NEAR OR SHORTLY AFTER MIDNIGHT. WILL POST A WIND
CHILL ADVISORY FOR ALL OF CENTRAL NC STARTING AT MIDNIGHT. WHILE
WIND CHILL VALUES ARE EXPECTED TO INCH ABOVE THE 0F MARK BETWEEN
ABOUT 12 NOON AND 5 PM THU... READINGS ARE LIKELY TO DIVE DOWN WELL
BELOW ZERO ONCE AGAIN AFTER 5 PM THU... STAYING DANGEROUSLY LOW
(EVEN APPROACHING -10F) THROUGH MID MORNING FRI. SINCE THU`S TIME
FRAME OF ABOVE-ZERO WIND CHILLS WILL BE SO SHORT... AND SINCE WE`D
STILL LIKE EVERYONE TO TAKE PROPER PRECAUTIONS AND NOT BE COMPLACENT
DURING THE DAYTIME AS WIND CHILLS WILL STILL BE VERY COLD... HAVE
OPTED TO TAKE THE UNUSUAL STEP (IN THIS UNUSUAL WEATHER SITUATION)
OF EXTENDING THE WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT ALL THE
WAY THROUGH FRI MORNING. EXPECT MOSTLY CLEAR SKIES THROUGH THIS
PERIOD... ALTHOUGH FLAT BROKEN STRATOCU THU MAINLY IN THE AFTERNOON
SHOULD BRING MOSTLY CLOUDY SKIES FOR A FEW HOURS. -GIH
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
THE LONG TERM BEGINS WITH A POSITIVELY TILTED UPPER LEVEL TROUGH
EXTENDING DOWN THE EAST COAST WITH A STRONG SURFACE HIGH CENTERED
OVER THE OHIO VALLEY. THIS WILL KEEP CENTRAL NC ROOTED IN THE COLD
AIR ADVECTION REGIME WITH NORTHERLY SFC FLOW AND NWLY FLOW ALOFT.
VERY COLD AND DRY AIRMASS WITH HIGHS ONLY IN THE LOW TO MID 20S. THE
SFC HIGH DRIFTS EAST AND SETS UP OVER EASTERN NC FRIDAY NIGHT WHICH
WILL TURN WINDS AROUND TO SOUTHERLY RETURN FLOW. THIS WILL NOT BE IN
TIME TO HELP TEMPS ALL THAT MUCH AS LOWS WILL BE IN THE MID TEENS.
STILL THIS IS WARMER THAN PREVIOUS NIGHTS. BACK TO WEST...AN
INVERTED TROUGH EXTENDING INTO THE TENNESSEE VALLEY FROM A PARENT
LOW OVER NORTH TEXAS WILL BE PRODUCING AN AREA OF STRONG LOW LEVEL
CONVERGENCE AND PRECIPITATION THAT IS THE PRECURSOR TO OUR NEXT
SYSTEM. INCREASING CLOUDS CAN BE EXPECTED AHEAD OF THIS SYSTEM LATE
FRIDAY NIGHT INTO SATURDAY MORNING.
OVERALL...MODELS HAVE COME INTO BETTER AGREEMENT WITH REGARD TO THE
EVOLUTION OF THE SYSTEM APPROACHING FROM THE WEST ON SATURDAY. THERE
STILL ARE FINER DIFFERENCES THAT MAY MATTER CONSIDERABLY IN HOW THE
FINAL SCENARIO PLAYS OUT. FIRST...THE EUROPEAN HAS PICKED UP THE LOW
PRESSURE WEST OF THE MOUNTAINS THAT THE GFS WAS SHOWING YESTERDAY. A
MUCH STRONGER WAVE IN THE UPPER LEVEL PATTERN OVER TEXAS IN THE GFS
IS PRODUCING A MUCH STRONGER LOW AND IS SLOWER WITH ITS PROGRESSION
UP THE BACK OF THE COLD FRONT. THIS WILL NOT MATTER IN REGARDS TO
POTENTIAL WINTER P-TYPE ON SATURDAY AS MUCH AS IT WILL FOR THE
TIMING OF THE ADVANCEMENT OF THE COLD FRONT THROUGH THE STATE ON
SUNDAY WHICH IS FASTER IN THE ECMWF. ANOTHER COMPROMISE THE MODELS
HAVE MADE IS WITH THE IN-SITU DAMMING SCENARIO AS THE SFC HIGH MOVES
OUT TO SEA. BOTH MODELS ARE NOW PRODUCING A WEDGE FRONT BUT IT IS
MUCH WEAKER IN THE GFS THEN PRIOR RUNS AND THE HIGH PUSHES FURTHER
OUT TO SEA FASTER THAN PREVIOUS RUNS AND THUS BOTH MODELS LOSE THE
WEDGE QUICKLY LATE SATURDAY AFTERNOON/EVENING. BECAUSE OF THIS...THE
OOZ RUN OF THE GFS HAS TRENDED A BIT WARMER AS ISENTROPIC LIFT WILL
BE LESS PRONOUNCED EARLIER IN THE DAY.
THE UPSHOT IN THE FORECAST SOUNDINGS IS A REAL GRAB BAG OF POTENTIAL
PRECIPITATION TYPES FOR THE TRIAD WITH APPRECIABLE DIFFERENCES
BETWEEN THE THERMAL PROFILES EVEN BETWEEN KGSO AND KINT. THE GENERAL
TREND WILL BE A GREATER LIKELIHOOD OF SNOW NORTH AND WEST AND LESS
SO APPROACHING GREENSBORO AND POINTS SOUTH AND EAST WHERE SLEET AND
EVEN FREEZING RAIN COULD BE MORE LIKELY. VERY EARLY FOR THESE
DETAILS TO BE IRONED OUT SO WE WILL CALL IT WINTERY MIX FOR NOW.
PRECIPITATION DOES LOOK CONFINED TO THE TRIAD HOWEVER AND POINTS
EAST OF HIGHWAY 1 SHOULD REMAIN DRY FOR MUCH OF THE DAY ON SATURDAY.
HIGHS GENERALLY IN THE LOWER 40S. EXPECT A NON-DIURNAL TEMPERATURE
CURVE FOR SATURDAY NIGHT WITH TEMPERATURES BEGINNING TO WARM
CONSIDERABLY AFTER 00Z SUNDAY AS WARM AIR ADVECTION AHEAD OF THE
COLD FRONT BEGINS. LOWS IN THE MID TO UPPER 30S OCCURRING EARLY IN
THE EVENING.
RAIN ASSOCIATED WITH THE COLD FRONT WILL MOVE IN FOR SUNDAY.
CONFIDENCE IN THIS BEING ALL LIQUID IS HIGH CONSIDERING THE
OVERNIGHT RISE IN TEMPERATURES WHICH WILL CONTINUE ON SUNDAY AND THE
LOSS OF SATURATION ALOFT IN THE ICE NUCLEATION ZONE. IN
FACT...TEMPERATURES WARM SO MUCH IN THE LOW LEVELS THAT INSTABILITY
CREEPS IN BY LATE SUNDAY AFTERNOON/EARLY EVENING AND LOW AND MID
LEVEL LAPSE RATES INCREASE. RISES ARE MINIMAL BUT WOULD NOT RULE OUT
THE CHANCE FOR A HEAVY CONVECTIVE SHOWER OR ISOLATED THUNDERSTORM.
HIGHS IN THE MID TO UPPER 50S. PRECIPITATION IS EXPECTED TO END
AFTER 6Z MONDAY. TOTAL QPF AMOUNTS ARE VERY UNCERTAIN AT THIS TIME
BUT EXPECT MORE IN THE TRIAD THAN POINTS EAST. LOWS IN THE MID TO
UPPER 30S.
COLDER AND DRIER BEHIND THE FRONT WITH NORTHEASTERLY SFC FLOW ON
MONDAY WITH HIGHS IN THE MID 40S AND LOWS MONDAY NIGHT IN THE UPPER
20S. DRY FOR TUESDAY AS WELL AS LOW PRESSURE MOVES INTO THE GREAT
LAKES REGION. HIGHS IN THE MID TO UPPER 40S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 640 AM WEDNESDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: SUB-VFR CIGS/VSBYS AT FAY
EARLY THIS MORNING... A PERIOD OF MVFR CIGS AND SCATTERED SNOW
SHOWERS TODAY FROM MID AFTERNOON TO EARLY EVENING... AND
STRONG/GUSTY WINDS THIS AFTERNOON THROUGH THE END OF THE TAF VALID
PERIOD.
AN AREA OF IFR-LIFR FOG OVER THE SOUTHERN SECTIONS OF CENTRAL NC...
INCLUDING FAY... WILL DRIFT SLOWLY EASTWARD OVER THE NEXT FEW
HOURS... ACCORDING TO THE LATEST HRRR GUIDANCE. MAINLY VFR
CONDITIONS ELSEWHERE THIS MORNING... EXCEPT FOR A CLUSTER OF MVFR
CLOUDS AT GSO PRIOR TO 14Z. A CLIPPER COLD FRONT WILL SWEEP ACROSS
THE AREA THIS AFTERNOON/EARLY EVENING... AT APPROXIMATELY 18Z-20Z AT
INT/GSO... 20Z-22Z AT RDU... AND 22Z-00Z AT FAY. A SHORT PERIOD
(LIKELY AROUND 2-3 HRS AT MOST) OF MVFR CIGS/VSBYS IN SNOW SHOWERS
IS EXPECTED WITH FRONTAL PASSAGE. SURFACE WINDS FROM THE SW WILL
INCREASE IN THE FEW HOURS BEFORE FRONTAL PASSAGE... THEN REMAIN
STRONG AND GUSTY AS THEY SHIFT TO NW BEHIND THE FRONT... LASTING
THROUGH 06Z. VFR CIGS/VSBYS ARE EXPECTED AFTER FRONTAL PASSAGE.
LOOKING BEYOND 12Z THU MORNING: BRISK AND OCCASIONALLY GUSTY NW
SURFACE WINDS WILL PERSIST THROUGH THU. VFR CONDITIONS ARE EXPECTED
TO DOMINATE THROUGH FRI NIGHT WITH FRIGID HIGH PRESSURE BUILDING IN.
ANOTHER STORM SYSTEM APPROACHING FROM THE WEST AND SW WILL BRING
LIKELY SUB-VFR CONDITIONS WITH PRECIPITATION STARTING IN THE NW
EARLY SAT MORNING BEFORE SPREADING AREAWIDE SAT. SUB-VFR CONDITIONS
AND STRONG/SHIFTING WINDS WILL LAST THROUGH SUN AS A WARM FRONT
TRACKS NORTHWARD THROUGH THE REGION. -GIH
&&
.CLIMATE...
THE FOLLOWING ARE RECORD LOW AND LOW MAXIMUM TEMPERATURES FOR
FEBRUARY 19TH...AND 20TH...FOR GSO...RDU...AND FAY...
RECORD LOWS
GSO RDU FAY
FEBRUARY 19: 12 IN 1979 11 IN 1979 8 IN 1958
FEBRUARY 20: 14 IN 1934 13 IN 1979 12 IN 1958
FEBRUARY 21: 13 IN 1959 8 IN 1896 16 IN 1958
RECORD LOW MAXIMUMS
GSO RDU FAY
FEBRUARY 19: 32 IN 1958 31 IN 1903 26 IN 1979
FEBRUARY 20: 29 IN 1947 32 IN 1947 37 IN 1972
&&
.RAH WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM
MIDNIGHT TONIGHT TO 9 AM EST FRIDAY FOR NCZ007>011-021>028-038>043-
073>078-083>086-088-089.
&&
$$ SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...HARTFIELD
CLIMATE...RAH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
359 PM EST WED FEB 18 2015
.SYNOPSIS...
AN ARCTIC FRONT AND POTENT UPPER LEVEL DISTURBANCE WILL BRING
SNOW SHOWERS OR EVEN A FEW HOUR PERIOD OF STEADIER SNOW TO THE
THIS AFTERNOON AND TONIGHT...WITH THE POTENTIAL FOR AN EXTENSIVE
NORTH- SOUTH BAND OF INTENSE...DANGEROUS SNOW SQUALLS MARCHING
ACROSS CENTRAL PENNSYLVANIA AND THE SUSQUEHANNA VALLEY THROUGH THE
LATE AFTERNOON AND EARLY EVENING. BITTER COLD TEMPERATURES AND
SUBZERO WIND CHILLS ARE EXPECTED TONIGHT...THROUGH THURSDAY AND INTO
FRIDAY MORNING.
A GRADUAL WARM-UP WILL OCCUR THIS COMING WEEKEND...BUT WITH IT
WILL COME A BOUT OF WINTRY WEATHER AS LOW PRESSURE ORGANIZES AND
MOVES NORTHEAST FROM THE MID MISSISSIPPI VALLEY TO THE EASTERN
GREAT LAKES REGION.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
LATEST RADAR HAS BANDS OF INCREASED SNOWFALL MOVING THROUGH THE
CENTRAL MOUNTAINS AND SLOWLY PROGRESSING EASTWARD. THE LATEST
SHORT TERM HI RES MODELS AND 18Z OPERATIONAL GUIDANCE...CONTINUE
TO SHOW THE AMPLIFYING UPPER TROUGH AND A SIGNIFICANT AND RATHER
STG SHORTWAVE MOVE THROUGH CENTRAL PA THIS AFTERNOON AND SWING
THROUGH THE EASTERN HALF OF PA THIS EVENING. THIS FEATURE WILL
ALSO ACT TO ENHANCE LLVL CONVERGENCE AND DEEP LAYER INSTABILITY
ALONG AND JUST AHEAD OF THE CFROPA. A HIGHLY UNUSUAL /AND
ANOMALOUS/ NORTH- SOUTH RIBBON OF MIXED LAYER CAPE OF 50-150 J/KG
IS FORMING JUST AHEAD OF THE ARCTIC BOUNDARY THIS AFTERNOON NEAR
THE ALLEGHENY FRONT. LATEST HRRR IS CURRENTLY SLOWING THE WAVES
PROGRESS AND BREAKING APART THE LINE AS IT MOVES EASTWARD. LATEST
NAM12 SNOW SQUALL PARAMETERS SHOWING ISALLOBARIC EFFECTS ON
OVERALL WIND SPEED. FRONTAL PASSAGE STILL PROGGED AROUND 00Z.
FOLLOWING THIS FRONT...MID AND UPPER FLOW WILL BE NEARLY PARALLEL
SUPPORTING ANAFRONT-LIKE PRECIP IN THE FORM OF A FEW TO SVRL HOUR
PERIOD OF LIGHT TO MDT SNOW -MAINLY ACROSS THE NW HALF OF THE
STATE.
MOST PLACES ACROSS CENTRAL PENN SHOULD SEE 1-2 INCHES OVER THE
NEXT 24 HOURS...WITH THE MTNS OF NRN PENN PICKING UP 2-3 INCHES
AND THE LAURELS SEE AS MUCH AS 3-5 INCHES BY EARLY THURSDAY
MORNING. A WINTER WEATHER ADVISORY CONTINUES FOR THE LAURELS TO
MIDNIGHT TONIGHT.
AS THE ARCTIC FRONT DROPS THROUGH THIS EVENING EXPECT GUSTY
NORTHWEST FLOW DEVELOPING LATE TODAY AND TONIGHT AND WIND CHILLS
WILL BECOME A FACTOR.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
WIND CHILL WARNINGS TONIGHT...BEGINNING AT MIDNIGHT FOR ALL OF
THE WESTERN AND NRN MTNS...WHILE WIND CHILL ADVISORIES WERE ISSUED
ELSEWHERE. THESE WIND CHILL PRODUCTS CONTINUE RIGHT THROUGH 15Z
FRIDAY AS THE COLD AIR MASS WILL MOVE OVER AND SIT OVER THE REGION
THROUGH FRIDAY.
LOWS TONIGHT BE AROUND -5 TO -10F ACROSS THE NW MTNS...TO THE
SINGLE DIGITS ABOVE ZERO THROUGH CENTRAL PA...TO NEAR 10F IN THE
SE.
HIGHS THURSDAY WILL STRUGGLE TO CLIMB ABOVE ZERO IN THE NW MTNS
/AND STAY JUST IN THE SINGLE DIGITS TO TEENS ELSEWHERE/ WITH
CONTINUED GUSTY NW WINDS UP TO 30-35 MPH AND OCNL FLURRIES AND
BANDS OF SNOW SHOWERS. THE SNOW SHOWERS COULD ADD ANOTHER COATING
TO 1/2 INCH IN THE CENTRAL RIDGE AND VALLEY REGION...AND ANOTHER
INCH POSSIBLE IN THE ALLEGHANIES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF COVERING THE CONUS EAST
OF THE ROCKIES AT THE START OF THE LONG TERM PERIOD IS FORECAST
TO SHIFT EAST AND TRANSITION THE UPPER FLOW TO A ZONAL PATTERN BY
THE WEEKEND. CORE OF ARCTIC AIR ALOFT IS FORECAST TO DROP INTO NRN
PA THURSDAY AFTN/EVE...SUPPORTING THE SHIFT IN THE UPPER FLOW. IN
RESPONSE TO ADDITIONAL COLD AIR/ENERGY DROPPING SOUTH ALONG THE
FRONT RANGE OVER THE WEEKEND...THE UPPER FLOW OVER THE EAST IS
FORECAST TO TURN SWRLY INTO NEXT WEEK. AS A RESULT...VERY COLD
AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE REST
OF THE WORK-WEEK.
THE FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY LOOK TO RISE WELL ABOVE THE FREEZING MARK
OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED MODERATION
IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT SHORTWAVE
TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE MID MISS
VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY... LEADING TO
THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN PA AND SNOW
OVER THEN NORTH. LATEST RUNS OF MDM RANGE GUIDANCE NOW DEVELOPS A
SFC LOW ALONG THE FRONT...POSSIBLY MOVING ACROSS PA. HAVE
INCREASED POPS...QPF AND POTENTIAL FOR A MESSY WINTER WEATHER
EVENT MAINLY DURING THE DAY SUNDAY.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL SYSTEM...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING BELOW NORMAL...BUT NOT AS FAR BELOW AS IN
RECENT DAYS. SCATTERED SNOW SHOWERS WILL TAPER OFF THROUGH EARLY
TUESDAY...THEN INCREASE OVER THE MTNS WEDNESDAY AS ANOTHER PUSH OF
ARCTIC AIR ARRIVES A SHORTWAVE ON WED.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
IFR AND LOWER CIGS AND VSBYS FROM FROM THE BEFORE MENTIONED TROUGH
AND ASSOCIATED SNOW SQUALLS AND SHOWERS WILL CONTINUE THROUGH 00Z. SHSN
SHOULD EVENTUALLY REACH INTO THE ERN AIRFIELDS WITH MVFR/IFR
RESTRICTIONS EXPECTED BETWEEN 21Z TO 00Z. INTENSE SNOW SQUALLS
WILL ACCOMPANY THE ARCTIC FROPA AND IS RESULTING IN RAPID DROP IN
VISBYS AOB 1/2SM. HAVE INCLUDED 1HR TEMPO OF 1/4 TO 1/2SM VISBYS
BASED ON THE LATEST HRRR AND NAM. SFC WINDS INITIALLY FROM
200-230 DEGREES WILL SHIFT TO 270-300 BEHIND THE FRONT WITH GUSTS
15-25MPH. PROLONGED IFR EXPECTED AT BFD/JST WITH COLD NW UPSLOPE
FLOW SHSN CONTINUING TONIGHT.
CONDITIONS WILL SLOWLY IMPROVE LATE TONIGHT INTO TOMORROW
MORNING...WITH VSBYS LIFTING BETWEEN 02Z TO 06Z...AT ALL TAF
SITES AND CIGS SLOWLY LIFTING TOWARDS MORNING.
OUTLOOK...
THU...MVFR/IFR -SHSN WRN 1/3. MAINLY VFR CENTRAL AND ERN TAFS.
FRI...BCMG VFR. NO SIG WX.
SAT-SUN...MVFR/IFR LKLY WITH MIXED PCPN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ004>006-010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/CERU
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
347 PM EST WED FEB 18 2015
.SYNOPSIS...
AN ARCTIC FRONT AND POTENT UPPER LEVEL DISTURBANCE WILL BRING
SNOW SHOWERS OR EVEN A FEW HOUR PERIOD OF STEADIER SNOW TO THE
THIS AFTERNOON AND TONIGHT...WITH THE POTENTIAL FOR AN EXTENSIVE
NORTH- SOUTH BAND OF INTENSE...DANGEROUS SNOW SQUALLS MARCHING
ACROSS CENTRAL PENNSYLVANIA AND THE SUSQUEHANNA VALLEY THROUGH THE
LATE AFTERNOON AND EARLY EVENING. BITTER COLD TEMPERATURES AND
SUBZERO WIND CHILLS ARE EXPECTED TONIGHT...THROUGH THURSDAY AND INTO
FRIDAY MORNING.
A GRADUAL WARM-UP WILL OCCUR THIS COMING WEEKEND...BUT WITH IT
WILL COME A BOUT OF WINTRY WEATHER AS LOW PRESSURE ORGANIZES AND
MOVES NORTHEAST FROM THE MID MISSISSIPPI VALLEY TO THE EASTERN
GREAT LAKES REGION.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
LATEST RADAR HAS BANDS OF INCREASED SNOWFALL MOVING THROUGH THE
CENTRAL MOUNTAINS AND SLOWLY PROGRESSING EASTWARD. THE LATEST
SHORT TERM HI RES MODELS AND 18Z OPERATIONAL GUIDANCE...CONTINUE
TO SHOW THE AMPLIFYING UPPER TROUGH AND A SIGNIFICANT AND RATHER
STG SHORTWAVE MOVE THROUGH CENTRAL PA THIS AFTERNOON AND SWING
THROUGH THE EASTERN HALF OF PA THIS EVENING. THIS FEATURE WILL
ALSO ACT TO ENHANCE LLVL CONVERGENCE AND DEEP LAYER INSTABILITY
ALONG AND JUST AHEAD OF THE CFROPA. A HIGHLY UNUSUAL /AND
ANOMALOUS/ NORTH- SOUTH RIBBON OF MIXED LAYER CAPE OF 50-150 J/KG
IS FORMING JUST AHEAD OF THE ARCTIC BOUNDARY THIS AFTERNOON NEAR
THE ALLEGHENY FRONT. LATEST HRRR IS CURRENTLY SLOWING THE WAVES
PROGRESS AND BREAKING APART THE LINE AS IT MOVES EASTWARD. LATEST
NAM12 SNOW SQUALL PARAMETERS SHOWING ISALLOBARIC EFFECTS ON
OVERALL WIND SPEED. FRONTAL PASSAGE STILL PROGGED AROUND 00Z.
FOLLOWING THIS FRONT...MID AND UPPER FLOW WILL BE NEARLY PARALLEL
SUPPORTING ANAFRONT-LIKE PRECIP IN THE FORM OF A FEW TO SVRL HOUR
PERIOD OF LIGHT TO MDT SNOW -MAINLY ACROSS THE NW HALF OF THE
STATE.
MOST PLACES ACROSS CENTRAL PENN SHOULD SEE 1-2 INCHES OVER THE
NEXT 24 HOURS...WITH THE MTNS OF NRN PENN PICKING UP 2-3 INCHES
AND THE LAURELS SEE AS MUCH AS 3-5 INCHES BY EARLY THURSDAY
MORNING. A WINTER WEATHER ADVISORY CONTINUES FOR THE LAURELS TO
MIDNIGHT TONIGHT.
AS THE ARCTIC FRONT DROPS THROUGH THIS EVENING EXPECT GUSTY
NORTHWEST FLOW DEVELOPING LATE TODAY AND TONIGHT AND WIND CHILLS
WILL BECOME A FACTOR.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
WIND CHILL WARNINGS TONIGHT...BEGINNING AT MIDNIGHT FOR ALL OF
THE WESTERN AND NRN MTNS...WHILE WIND CHILL ADVISORIES WERE ISSUED
ELSEWHERE. THESE WIND CHILL PRODUCTS CONTINUE RIGHT THROUGH 15Z
FRIDAY AS THE COLD AIR MASS WILL MOVE OVER AND SIT OVER THE REGION
THROUGH FRIDAY.
LOWS TONIGHT BE AROUND -5 TO -10F ACROSS THE NW MTNS...TO THE
SINGLE DIGITS ABOVE ZERO THROUGH CENTRAL PA...TO NEAR 10F IN THE
SE.
HIGHS THURSDAY WILL STRUGGLE TO CLIMB ABOVE ZERO IN THE NW MTNS
/AND STAY JUST IN THE SINGLE DIGITS TO TEENS ELSEWHERE/ WITH
CONTINUED GUSTY NW WINDS UP TO 30-35 MPH AND OCNL FLURRIES AND
BANDS OF SNOW SHOWERS. THE SNOW SHOWERS COULD ADD ANOTHER COATING
TO 1/2 INCH IN THE CENTRAL RIDGE AND VALLEY REGION...AND ANOTHER
INCH POSSIBLE IN THE ALLEGHANIES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
AXIS OF LONGITUDINALLY BROAD UPPER TROF COVERING THE CONUS EAST
OF THE ROCKIES AT THE START OF THE LONG TERM PERIOD IS FORECAST
TO SHIFT EAST AND TRANSITION THE UPPER FLOW TO A ZONAL PATTERN BY
THE WEEKEND. CORE OF ARCTIC AIR ALOFT IS FORECAST TO DROP INTO NRN
PA THURSDAY AFTN/EVE...SUPPORTING THE SHIFT IN THE UPPER FLOW. IN
RESPONSE TO ADDITIONAL COLD AIR/ENERGY DROPPING SOUTH ALONG THE
FRONT RANGE OVER THE WEEKEND...THE UPPER FLOW OVER THE EAST IS
FORECAST TO TURN SWRLY INTO NEXT WEEK. AS A RESULT...VERY COLD
AIR WILL CONTINUE TO IMPACT THE REGION THROUGH AT LEAST THE REST
OF THE WORK-WEEK.
THE FLATTENING OF THE UPPER FLOW OVER THE NORTHEAST THIS COMING
WEEKEND WILL LEAD TO A MODERATION AWAY FROM THE BITTER COLD WE
HAVE EXPERIENCED IN THE CURRENT PATTERN.
THE CENTER OF THIS NEXT ARCTIC HIGH MAY SLIDE JUST SOUTH OF THE
REGION THEN OFF THE MID ATLANTIC COAST - PER THE 00Z EC...WHILE
THE GEFS WOULD SUGGEST A LITTLE MORE IN THE WAY OF LLVL COLD AIR
DAMMING OVER THE CWA...PRECEDING INCREASING MOISTURE AND A WINTRY
MIX OR SNOW SPREADING IN FROM THE SW...THEN ANOTHER PUSH OF
ARCTIC AIR FOR LATE SUNDAY AND MONDAY.
TEMPERATURES SUNDAY HOLD THE POTENTIAL TO RISE ABOVE THE FREEZING
MARK OVER A GOOD PART OF CENTRAL PA AS THE EARLIER MENTIONED
MODERATION IN THE UPPER FLOW IS FORECAST TO ARRIVE. THE NEXT
SHORTWAVE TROF/SFC FRONT IS ALSO CURRENTLY TIMED TO MOVE FROM THE
MID MISS VALLEY TO ERN GLAKES REGION THIS SATURDAY AND SUNDAY...
LEADING TO THE POSSIBILITY OF SNOW OR RAIN FOR A CHANGE OVER SRN
PA AND SNOW OVER THEN NORTH.
AS HIGH PRESSURE MOVES ACROSS THE REGION NEXT MONDAY AND TUESDAY
BEHIND SUNDAY`S POTENTIAL FROPA...DRY WEATHER IS EXPECTED WITH
TEMPS AGAIN RETURNING BELOW NORMAL...BUT NOT AS FAR BELOW AS IN
RECENT DAYS.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
IFR AND LOWER CIGS AND VSBYS FROM FROM THE BEFORE MENTIONED TROUGH
AND ASSOCIATED SNOW SQUALLS AND SHOWERS WILL CONTINUE THROUGH 00Z. SHSN
SHOULD EVENTUALLY REACH INTO THE ERN AIRFIELDS WITH MVFR/IFR
RESTRICTIONS EXPECTED BETWEEN 21Z TO 00Z. INTENSE SNOW SQUALLS
WILL ACCOMPANY THE ARCTIC FROPA AND IS RESULTING IN RAPID DROP IN
VISBYS AOB 1/2SM. HAVE INCLUDED 1HR TEMPO OF 1/4 TO 1/2SM VISBYS
BASED ON THE LATEST HRRR AND NAM. SFC WINDS INITIALLY FROM
200-230 DEGREES WILL SHIFT TO 270-300 BEHIND THE FRONT WITH GUSTS
15-25MPH. PROLONGED IFR EXPECTED AT BFD/JST WITH COLD NW UPSLOPE
FLOW SHSN CONTINUING TONIGHT.
CONDITIONS WILL SLOWLY IMPROVE LATE TONIGHT INTO TOMORROW
MORNING...WITH VSBYS LIFTING BETWEEN 02Z TO 06Z...AT ALL TAF
SITES AND CIGS SLOWLY LIFTING TOWARDS MORNING.
OUTLOOK...
THU...MVFR/IFR -SHSN WRN 1/3. MAINLY VFR CENTRAL AND ERN TAFS.
FRI...BCMG VFR. NO SIG WX.
SAT-SUN...MVFR/IFR LKLY WITH MIXED PCPN.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ004>006-010>012-017-018-024-033-037-041-042.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR PAZ019-025>028-034>036-045-046-049>053-056>059-063>066.
WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT/CERU
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...CERU/STEINBUGL
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1209 PM EST WED FEB 18 2015
.SYNOPSIS...
ARCTIC COLD FRONT PLOWS THROUGH OUR AREA THIS AFTERNOON. RECORD
AND DANGEROUSLY COLD TEMPERATURES WILL BE FOUND TONIGHT THROUGH
FRIDAY. ANOTHER STORM SYSTEM ARRIVES THIS WEEKEND WITH A WINTER
WEATHER THREAT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM EST WEDNESDAY...
STRONG ARCTIC FRONT STILL ON TRACK TO CROSS THE MOUNTAINS EARLY
THIS AFTERNOON AND OUT EAST LATE IN THE DAY. VERY DYNAMIC SETUP
WITH VERY COLD AIR ALOFT ROTATING THROUGH THE 5H TROUGH WITH A
PASSING VORT AXIS ALONG THE BOUNDARY VERY SIMILAR TO A CONVECTIVE
SCENARIO IN THE SPRING. PROVIDED SOME HEATING/MOISTENING OF THE
BOUNDARY LAYER PER SW FLOW JUST AHEAD OF THE BOUNDARY ESPCLY BLUE
RIDGE EAST EXPECT SHALLOW CONVECTION TO DEVELOP OFF THE RIDGES
EARLY THIS AFTERNOON BEFORE SWEEPING EAST IN BROKEN BAND FASHION
LATER ON. LATEST SPC DAY1 OUTLOOK HAS GENERAL THUNDER OVER MUCH OF
THE CENTRAL/EAST SO INCLUDED THUNDER GIVEN SMALL FORECAST CAPE
AND SOME HEAVIER SNOW SQUALLS PER HRRR UNDER SUCH STRONG SURFACE-
7H LAPSES OFF FORECAST SOUNDINGS. THIS COULD TRANSLATE SOME
STRONGER WINDS TO THE GROUND WITHIN ANY OF THE HEAVIER SNOW
SHOWERS WITH A QUICK INCH OR TWO OF SNOW POSSIBLE.
THUS WENT AHEAD AND INCLUDED SOME THUNDER/GUSTY WIND MENTION
WHILE EXTENDING THE WESTERN WINTER WEATHER ADVISORY EAST TO THE
BLUE RIDGE TO COVER MORE IMPACT RELATED SNOWFALL WHICH MAY ONLY
LAST AN HOUR OR TWO RIGHT AHEAD OF THE FRONT. SOME OF THIS
CONVECTION LIKELY TO HEAD EAST INTO THE WARMER BOUNDARY LAYER
WHERE PLAN TO COVER WITH STATEMENTS FOR NOW PENDING LATER
COVERAGE. OTRW BUMPED UP POPS AND ROLLED POSSIBLE WIND ADVISORY
GUSTS INTO THE WINTER WEATHER ADVISORY. RAISED HIGH TEMPS A NOTCH
IN THE FAR WEST GIVEN CURRENT OBS AND OUT EAST WHERE THINK A
BETTER SHOT AT RECOVERY WITH SOME SPOTS PERHAPS NEAR 40 IF THE
FRONT DOES SLOW UP SOME.
PREVIOUS DISCUSSION AS OF 345 AM EST WEDNESDAY...
NOT MUCH OF BREAK FROM OLD MAN WINTER. ARCTIC FRONT UPSTREAM
ACROSS THE OHIO VALLEY WILL SHIFT EAST ACROSS US TODAY. WILL BE
DEALING FIRST WITH SNOW SHOWERS AND BLOWING SNOW. HIGH-RES MODELS
SEEMED TO HAVE A DECENT HANDLE ON UPSTREAM OBS. INSTABILITY
ACTUALLY INCREASES AT TIMES THROUGH THIS AFTERNOON ENOUGH THAT
SNOW SQUALLS WILL OCCUR. CANNOT RULE OUT THUNDER...BUT ITS
MARGINAL. SITUATION LOOKS SOMEWHAT SIMILAR TO WHAT WE HAD LAST
WEEKEND. THIS DEEPENING TROUGH TO PUSH ARCTIC AIR EAST BY THIS
EVENING. SNOW SHOWERS WILL BE MOST PREVALENT OVER THE MOUNTAINS
BUT AS THE AFTERNOON MOVES ON...EXPECT STREAMERS OF SNOW TO REACH
INTO THE PIEDMONT...WITH SOME AXIS OF FRONTOGENESIS OCCURRING THIS
EVENING ACROSS THE PIEDMONT WITH EPV ALSO IN PLACE...WHICH MAY
LEAD TO MORE COVERAGE EAST OF OUR AREA.
AS FAR AS TOTAL SNOWFALL...THROUGH MIDNIGHT TONIGHT WILL LIKELY
SEE 1 TO 3 INCHES IN THE MOUNTAINS...WITH UP TO 6 INCHES IN WRN
GREENBRIER AND HIGHER TERRAIN OF SW VA/NW NC. AS SUCH HAVE
EXTENDED THE WINTER WX ADVISORY TIL MIDNIGHT TONIGHT. AFTER THAT
THE WIND CHILL WARNING PRODUCT WILL INCLUDE ANY ADDITIONAL
ACCUMULATIONS THAT OCCUR INTO THURSDAY.
TEMPERATURES THIS MORNING WILL START TO RISE AHEAD OF THE FRONT
WITH HIGHS IN THE LOWER TO MID 30S SOUTHEAST TO TEENS/20S WEST.
TEMPS SHOULD FALL TO THE TEENS IN THE WEST BY EVENING WITH UPPER
20S EAST. ARCTIC AIR LAGS BEHIND THE ACTUAL FRONT SOME...SO A
DELAY IS EXPECTED IN THE PIEDMONT.
WINDS SHOULD BEGIN TO INCREASE WITH THE SNOW SHOWERS AND FRONT
TODAY. MODELS HAVE NEAR ADVISORY LEVEL GUSTS IN THE NC MTNS...BUT
NOT SEEING AS LOW OF AN INVERSION...SO SHOULD KEEP WINDS UNDER 50
MPH GUSTS.
AT MIDNIGHT...WIND CHILLS SHOULD START TO REACH INTO ADVISORY
LEVELS IN THE MOUNTAINS BUT QUICKLY DROP TO 20 BELOW BY
MORNING...WHILE THE PIEDMONT AND FOOTHILLS DROP TO 0 TO 10 BELOW
ZERO BY THURSDAY MORNING. PER COLLABORATION WITH NEIGHBORING NWS
OFFICES WE DECIDED TO RUN THE WIND CHILL HEADLINES THROUGH FRIDAY
MORNING...AS THURSDAY WILL NOT SEE TOO MUCH OF A WARMUP.
WILL DROP THE WINTER WX ADVISORY FOR BLACK ICE IN NC BY 7AM.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 AM EST WEDNESDAY...
A CLOSED UPPER LEVEL LOW WILL TRACK ACROSS PENNSYLVANIA THURSDAY.
THIS SYSTEM WILL BRING LIGHT UPSLOPE SNOW SHOWERS TO WESTERN SLOPES
WITH CLOUDS SPREADING EAST INTO THE PIEDMONT. CLOUDS AND LIGHT SNOW
IS THE LEAST OF OUR WORRIES AS AN ARCTIC AIRMASS WILL KEEP THE
REGION COLD WITH SINGLE DIGITS ACROSS THE MOUNTAINS AND MID TO UPPER
TEENS EAST DURING THE DAY THURSDAY. STRONG WINDS WILL ALSO BLOW
ACROSS THE AREA THURSDAY WITH A TIGHT PRESSURE GRADIENT FROM THE LOW
TO THE NORTH AND HIGH PRESSURE ENTERING THE OHIO VALLEY. THE
COMBINATION OF VERY COLD TEMPERATURES AND STRONG WINDS WILL KEEP
WIND CHILL VALUES BELOW ZERO FOR MUCH OF THE DAY. THE PIEDMONT WIND
CHILLS MAY GO ABOVE ZERO THURSDAY AFTERNOON FOR A FEW HOURS ONLY TO
DROP BACK DOWN THURSDAY NIGHT. FOR SIMPLICITY SAKE AND IMPACT FROM
THIS HISTORIC EVENT...WE WILL CONTINUE WITH WIND CHILL WARNINGS
ALONG AND WEST OF THE BLUE RIDGE AND ADVISORIES EAST OF THE BLUE
RIDGE INTO FRIDAY MORNING. IF HIGH PRESSURE BUILDS IN OVER THE AREA
ALLOWING WINDS TO DECOUPLE...WE COULD DOWN GRADE HEADLINES LATER. NO
MATTER HOW YOU LOOK AT IT...WIND OR NO WIND...IT WILL BE A BITTER
COLD PERIOD INTO THURSDAY INTO FRIDAY MORNING.
HIGH PRESSURE TRACKS ACROSS THE REGION FRIDAY. WITH A DRY AIRMASS
AND ABUNDANT SUNSHINE...TEMPERATURES WILL SEEMS MILD WITH HIGHS IN
THE 20S. HIGH PRESSURE SLIDES OFF THE VIRGINIA AND NORTH CAROLINA
COAST FRIDAY NIGHT...ALLOWING A WARM FRONT TO TRACK NORTH ACROSS THE
TENNESSEE-SOUTHERN OHIO VALLEYS. CLOUDS SHOULD HOLD OFF FRIDAY
EVENING AND WITH GOOD RADIATIONAL COOLING...SEND TEMPERATURES DOWN
INTO THE SINGLE DIGITS ACROSS MOUNTAIN VALLEYS AND POINTS EAST OF
THE BLUE RIDGE. WARM AIR WORKING IN ALOFT WILL KEEP RIDGES
TEMPERATURES 10F WARMER THAN EVERYONE ELSE.
ISENTROPIC LIFT AND SHORT WAVES ALONG THE WARM FRONT WILL PUSH
MOISTURE IN ACROSS SOUTHWESTERN VIRGINIA LATE FRIDAY NIGHT...THEN
OVER SPREAD THE REGION DURING THE DAY SATURDAY. PRECIPITATION LIKELY
TO START AS SNOW...THEN TRANSITION TO SLEET BEFORE BECOMING ALL RAIN
BY LATE IN THE AFTERNOON. PRECIPITATION FALLING INTO EXITING RIDGE
WILL CREATE AN INSITU WEDGE. MODELS ARE KEEPING TEMPERATURES IN A
30F-33F RANGE ALONG THE BLUE RIDGE AND NORTH OF HWY 460 INTO
SATURDAY AFTERNOON. THESE AREAS WILL KEEP SNOW LONGER UNLESS WARM
NOSES IS STRONGER AND IN THAT CASE...SLEET INTO THE AFTERNOON. FOR
NOW...KEEPING P-TYPE AS RAIN/SNOW. WARMER AIR OVER TAKE THE FORECAST
AREA SATURDAY NIGHT FOR ALL P-TYPE TO BE RAIN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 315 AM EST WEDNESDAY...
INSITU WEDGE WILL ERODE OVERNIGHT AS LOW PRESSURE TRACKS INTO THE
OHIO VALLEY. PRECIPITATION INTENSITY WILL WANE OVERNIGHT AS THE WARM
FRONT TRACKS NORTH AND WE AWAIT THE COLD FRONTAL PASSAGE SUNDAY
AFTERNOON. P-TYPE SHOULD BE ALL LIQUID (RAIN/DRIZZLE) BY LATE
SATURDAY NIGHT INTO SUNDAY. THE FRONT CROSSES THE MOUNTAINS SUNDAY
AFTERNOON...THEN THE PIEDMONT EARLY IN THE EVENING. TEMPERATURES
WILL GET A BOOST AHEAD OF THE COLD FRONT WITH UPPER 40S TO LOWER 50S
FORECASTED FOR SUNDAY. TEMPERATURES DROP BACK INTO THE 20S SUNDAY
NIGHT WITH SCATTERED MOUNTAIN SNOW SHOWERS INTO THE DAY MONDAY.
TEMPERATURES MONDAY AND TUESDAY WILL RUN BELOW NORMAL.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1158 AM EST WEDNESDAY...
MVFR TO IFR CONDITIONS IN LOW CIGS AND SNOW SHOWERS TO PERSIST AT
KBLF/KLWB THROUGH THE AFTERNOON. MAIN BAND OF MODERATE SNOW
SHOWERS/SNOW SQUALLS TO ACCOMPANY AN ARCTIC FRONT ACROSS THE BLUE
RIDGE INCLUDING KBCB/KROA BY 18Z/1PM...REACHING...AND KLYH/KDAN
19-21Z. KEPT TEMPO GROUPS FOR POTENTIAL STRONG WIND GUSTS AND
LOWER VSBYS/CIGS AT ALL SITES. EXPECT TO RETURN TO VFR EAST OF THE
MTNS BY EVENING WITH SNOW SHOWERS PERSISTING AT KBLF/KLWB INTO
THE EVENING TAPERING OFF OVERNIGHT...BUT CIGS STAYING MVFR. WINDS
WILL BE INCREASING AND VEERING TO THE WEST WITH THE SNOW SHOWERS
AND BEHIND THE FRONT. GUSTS TO 25 TO 40 KTS NOT OUT OF THE
QUESTION ESPCLY WITHIN THE HEAVIER BAND OF SNOW SHOWERS.
UPSLOPE MVFR TO CONTINUE INTO THURSDAY IN SOUTHEAST WEST VA...WITH
VFR EAST.
WIDESPREAD VFR RETURNS FOR ALL LOCATIONS THURSDAY NIGHT INTO
FRIDAY UNDER DRY/ARCTIC HIGH PRESSURE. CLOUDS WILL INCREASE
FRIDAY NIGHT BUT LIKELY STILL VFR.
ANOTHER COMPLEX STORM SYSTEM WILL AFFECT THE AREA SATURDAY INTO
SUNDAY WITH SUB VFR CONDITIONS AND A MIX OF WINTER WEATHER.
IMPROVING CONDITIONS SHOULD TAKE SHAPE SUNDAY NIGHT WITH A RETURN
TO VFR MOST SITES MONDAY EXCLUDING SOUTHEAST WEST VA WHERE MVFR
CIGS AND FLURRIES MAY PERSIST.
&&
.CLIMATE...
LOW MAXIMUM (COLDEST HIGH) TEMPERATURE RECORDS FOR THURSDAY (FEB 19).
ROA 28/1958
LYH 25/1903
DAN 20/1979
BLF 20/1960
LWB 28/2006
RNK 10/1958
LOW MINIMUM (COLDEST LOWS) TEMPERATURE RECORDS FOR THURSDAY AND FRIDAY.
2/19 2/20
ROA 7/1979 9/1979
LYH 8/1903 7/1896
DAN 11/1973 10/1979
BLF 3/1993 8/1960
LWB 3/2006 6/1979
RNK -2/1958 2/1972
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
VAZ011>014-016>020-022>024-032.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ007-009>020.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ007-
009-010-015.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR VAZ022>024-032>035-043>047-058-059.
NC...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR NCZ003-
019-020.
WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ001-002-018.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NCZ001-
002-018.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR NCZ003>006-019-020.
WV...WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 10 AM EST FRIDAY
FOR WVZ042>044-507-508.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
WVZ042>044-507-508.
&&
$$
SYNOPSIS...JH/PH
NEAR TERM...JH/WP
SHORT TERM...RCS
LONG TERM...KK
AVIATION...AMS/JH/WP
CLIMATE...PH