Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/20/16
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
745 PM MST TUE JAN 19 2016
.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM WILL BRING A CHANCE OF LIGHT PRECIPITATION
TO MAINLY NORTHERN ARIZONA TONIGHT. HIGH PRESSURE WILL BUILD ACROSS
THE DESERT SOUTHWEST WEDNESDAY CONTINUING INTO THE WEEKEND.
TEMPERATURES A FEW DEGREES ABOVE NORMAL ARE EXPECTED BY LATE IN THE
WEEK.
&&
.DISCUSSION...
A VIGOROUS SHORTWAVE TROUGH WAS PROPAGATING THROUGH NEVADA AND
SOUTHEAST CALIFORNIA EARLY THIS EVENING ON THE LEADING EDGE OF A
120KT JET STREAK. STRONG JET LEVEL DIVERGENCE COMBINED WITH MOIST
(ALBEIT WEAK) H7 FRONTOGENTICAL FORCING HAS ALLOWED A BAND OF
PRECIPITATION TO BE MAINTAINED INTO THE LOWER COLORADO RIVER VALLEY.
THE PAST SEVERAL HRRR ITERATIONS HAVE VERY ACCURATELY DEPICTED THIS
EVOLUTION...AND EVEN CAPTURE THE CURRENT DETERIORATION STAGE SEEN IN
RADAR LOOPS.
EARLIER IN THE EVENING...HAD INCREASED POPS THROUGH RIVERSIDE COUNTY
TO ACCOUNT FOR RADAR TRENDS YIELDING A MODEST CHANCE...THOUGH LOW
QPF EVENT. KEPT ANY PRECIPITATION MENTION EXCLUSIVELY RELEGATED TO
LA PAZ AND UPSLOPE AREAS OF MARICOPA AND GILA COUNTIES FOR THE
REMAINDER OF THE NIGHT (AND SIMILARLY BARELY MEASURING IN THE
BUCKET)...AND PALTRY RADAR TRENDS BEAR THIS TREND OUT.
OTHERWISE...BOTH TEMPERATURES AND DEWPOINTS WERE TRENDING SLIGHTLY
HIGHER THAN FORECAST GIVEN THE INFUSION OF CLOUDS AND
MOISTURE...THOUGH OBSERVATIONAL READINGS SHOULD MODERATE LATER
TONIGHT WITH THE PASSAGE OF THE TROUGH AXIS AND CLOUD SHIELD.
&&
.PREVIOUS DISCUSSION...
/301 PM MST TUE JAN 19 2016/
RIDGING WILL BUILD INTO THE DESERT SOUTHWEST BEHIND THIS TROUGH ON
WEDNESDAY AND REMAIN IN PLACE THROUGH AT LEAST SATURDAY. SATURDAY
NIGHT WILL SEE THE TAIL END OF A WEAK TROUGH MOVE THROUGH SOUTHERN
CALIFORNIA AND ARIZONA. HOWEVER...A NEGLIGIBLE INCREASE IN PRE-
FRONTAL MOISTURE AND LITTLE TO NO NOTEWORTHY ISENTROPIC ASCENT WILL
PRECLUDE WIDESPREAD PRECIP DEVELOPMENT ACROSS THE AREA. NAEFS STILL
MAINTAINS 10 POPS EAST OF PHOENIX AND THIS SEEMS
REASONABLE...OTHERWISE SINGLE DIGIT POPS APPEAR TO BE ALL THAT IS
WARRANTED. WEAK RIDGING WILL RETURN EARLY NEXT WEEK.
AS FOR TEMPERATURES...EXPECT BOTH HIGHS AND LOWS TO BE WITHIN A FEW
DEGREES OF NORMAL THROUGH SATURDAY. WEAK POST-FRONTAL COLD ADVECTION
COULD KNOCK TEMPS BACK INTO THE LOW/MID 60S SUNDAY AND MONDAY BUT
ASIDE FROM THAT...NO MAJOR DEPARTURES FROM NORMAL ARE EXPECTED AT ANY
TIME OVER THE NEXT WEEK.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
VERY LITTLE AVIATION CONCERNS THROUGH WEDNESDAY EVENING...WITH
THICKER MID/HIGH CIGS AOA 10K FT CLEARING BY SUNRISE WEDNESDAY.
VIRGA AND A FEW SPRINKLES REACHING THE SFC MAY BE POSSIBLE THIS
EVENING...BUT LITTLE TO IMPACT OPERATIONS. OTHERWISE...SFC WINDS
WILL REMAIN LIGHT AND FOLLOW TYPICAL DIURNAL DIRECTION TRENDS AROUND
THE PHOENIX AREA...WITH WEST AND NORTH COMPONENTS ACROSS SOUTHEAST
CALIFORNIA.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
A HIGH PRESSURE RIDGE WILL DOMINATE THE AREA THURSDAY AND FRIDAY
BRINGING A SLIGHT WARMING TREND WITH SLIGHTLY ABOVE NORMAL HIGH
TEMPERATURES THROUGH FRIDAY. THEN THE NEXT WEAK SYSTEMS MOVE THROUGH
FRIDAY NIGHT/SATURDAY MORNING AND SUNDAY HELPING TO BRING HIGH
TEMPERATURES BACK TO NEAR NORMAL ON SATURDAY AND SLIGHTLY BELOW
NORMAL SUNDAY ALONG WITH VERY LITTLE CHANCE OF RAIN. EXPECT WINDS TO
BE GENERALLY LIGHT AND FOLLOW USUAL DIURNAL TENDENCIES WITH SOME
AFTERNOON WESTERLY AND NORTHWESTERLY BREEZES ON SUNDAY AFTERNOON IN
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA WITH WIND GUSTS OF ABOUT
15 TO 22 KNOTS. MINIMUM HUMIDITIES WILL RANGE FROM THE MID/UPPER
TEENS TO THE LOW/MID 20S PERCENT RANGE ON ALL DAYS EXCEPT FOR SUNDAY
WHEN THEY WILL TEMPORARILY BUMP UP TO THE UPPER 20S TO MID 30S
PERCENT RANGE. EXPECT GOOD TO EXCELLENT OVERNIGHT RECOVERIES.
&&
.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MO/HIRSCH/LEINS
AVIATION...MO
FIRE WEATHER...SAWTELLE
AS MENTIONED IN PREVIOUS FORECAST DISCUSSIONS...A SLOW MOVING
TRANSIENT RIDGE WILL PASS OVER THE AREA THURSDAY AND FRIDAY
SHIELDING THE AREA FROM SNOW. MODEL AGREEMENT BETWEEN THE ECMWF
AND GFS SOLUTIONS NOT GREAT THIS WEEKEND BUT NOT ENTIRELY
DISSIMILAR EITHER. IN ANY CASE...BOTH INDICATED THAT UNSETTLED
PROGRESSIVE FLOW WILL REDEVELOP WITH SNOW POSSIBLE BOTH SATURDAY
AND SUNDAY. LITTLE DISCERNIBLE DETAIL TO BE GLEANED FROM THE
LATEST FORECAST RUNS AS TIMING AND DEPTH OF TROUGHS DIFFER.
TEMPERATURES THROUGHOUT THE REMAINDER OF THE WEEK WILL BOUNCE UP
AND DOWN A BIT WITH THE PASSAGE OF THE SERIES OF SHALLOW TROUGH
SYSTEMS DESCRIBED PREVIOUSLY. HOWEVER...THOUGH READINGS WILL SHOW
SOME VARIANCE...THEY WILL GENERALLY REMAIN WITHIN A FEW DEGREES OR
MORE OF NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1110 AM MST MON JAN 18 2016
WIDESPREAD VFR UNTIL 00Z-03Z WHEN CONDITIONS DETERIORATE FROM
RAPIDLY LOWER CIGS AS MOIST TROUGH MOVING INTO WRN COLORADO. CIGS
WILL QUICKLY LOWER BELOW ILS BREAKPOINTS AT THE MOUNTAIN TAF
SITES WITH AREAS OF IFR CONDITIONS. WIDESPREAD BLO 3SM -SN BR IS
EXPECTED BETWEEN 06Z-12Z TONIGHT...ALTHOUGH THE SNOW STAY EAST OF
KCNY.
RAPID IMPROVEMENT DURING 12Z-18Z TUESDAY WITH IMPROVING VIS AND
RISING CIGS ARE EXPECTED...ALTHOUGH CIGS MAY LINGER AT KEGE AND
KASE. WIDESPREAD VFR IS EXPECTED BY 15Z-18Z TUESDAY MORNING.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR COZ014.
UT...NONE.
&&
$$
UPDATE...PF
SHORT TERM...EH
LONG TERM...NL
AVIATION...PF
AREA FORECAST DISCUSSION
NWS ALBANY NY
1230 AM EST MON JAN 18 2016
.SYNOPSIS...
A QUICK MOVING...CLIPPER...LOW PRESSURE SYSTEM WILL APPROACH
AND WILL MOVE ACROSS THE REGION TONIGHT BRINGING MAINLY A LIGHT
SNOWFALL TO THE AREA. IN THE WAKE OF THIS SYSTEM...AN ARCTIC
AIRMASS WILL BE USHERED IN ON BRISK AND GUSTY WESTERLY WINDS.
TEMPERATURES MONDAY NIGHT WILL DROP INTO THE SINGLE DIGITS AND
BELOW ZERO ACROSS MUCH OF THE LOCAL AREA. LAKE EFFECT SNOWS WILL
DEVELOP DOWNWIND OF LAKE ONTARIO MONDAY MORNING AND WILL PERSIST
THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1230 AM EST...A FAST MOVING CLIPPER SYSTEM IS HEADED
TOWARDS THE AREA. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS
NOW LOCATED OVER THE WESTERN MOHAWK VALLEY AND ADIRONDACKS AND
HEADING EAST/SOUTHEAST. SOME AREAS OF VERY LIGHT SNOW/SNOW
SHOWERS HAS ALREADY BROKEN OUT ACROSS THE MOHAWK VALLEY AND
WESTERN ADIRONDACKS...CAPITAL REGION AND OVER WESTERN NEW ENGLAND.
HOWEVER...THERE APPEARS TO BE SOME MID LEVEL DRYING AND
SUBSIDENCE...POSSIBLY PARTIALLY DUE TO THE DEEPENING LOW PRESSURE
SYSTEM OFF THE COAST...WHICH HAS BEEN ALLOWING THE SNOW TO REMAIN
VERY LIGHT/LIMITED IN VALLEY AREAS THUS FAR.
THE HEAVIER SNOW SHOWERS ALONG THE FRONT ARE NOW LOCATED ACROSS
THE WESTERN MOHAWK VALLEY AND ADIRONDACKS...AND HAVE BECOME
SOMEWHAT SPOTTY UPON HEADING EAST. STILL EXPECT UP TO A QUICK INCH
FROM THIS BAND AS IT CROSSES THE MOHAWK VALLEY AND WESTERN
ADIRONDACKS WITHIN A QUICK...45-90 MINUTE PERIOD. THEREAFTER...THE
SNOW SHOWERS SHOULD TRANSITION MORE INTO LAKE EFFECT...WITH
GREATEST SNOWFALL THROUGH SUNRISE EXPECTED ACROSS CENTRAL AND
SOUTHERN HERKIMER CO.
FURTHER SOUTH...THE LATEST 3KM HRRR SUGGEST THAT AREAS OF LIGHT
SNOW WITH SOME HEAVIER EMBEDDED BURSTS WILL CONTINUE TO MOVE
ACROSS THE AREA DURING THE OVERNIGHT HOURS /MAINLY AFTER MIDNIGHT/
AS THE CLIPPER SYSTEM MOVES THROUGH. THERE COULD BE A LOCALIZED
SQUALL RIGHT ALONG WITH THE PASSAGE OF THE CLIPPER/S COLD FRONT
OVERNIGHT...WITH A BRIEF BURST OF HEAVY SNOW...GUSTY WINDS AND
LOW VISIBILITY. ANY SQUALL WILL BE VERY SHORT IN DURATION...AND
SHOULD BE LIMITED IMPACT DUE TO IT/S OCCURRING IN THE MIDDLE OF
THE NIGHT. STILL...ANY OVERNIGHT TRAVELERS SHOULD BE AWARE THAT
THE WEATHER WILL BE LESS THAN IDEAL FOR DRIVING LATE TONIGHT.
TOTAL ACCUMS SHOULD MAINLY BE LESS THAN AN INCH IN VALLEY
AREAS...EXCEPT POSSIBLY 1-2 INCHES FROM SARATOGA NORTH TO GLENS
FALLS. HIGHER TERRAIN SHOULD STILL EXPERIENCE 1-2 INCHES.
A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR NORTHERN HERKIMER
AND HAMILTON COUNTIES...WHERE THE BEST QPF IS EXPECTED TO
OCCUR...AND SOME LAKE ENHANCEMENT/UPSLOPE WILL AID IN ALLOWING
SNOWFALL TOTALS OVERNIGHT TO BE AROUND 2-6 INCHES.
ELSEWHERE...GENERALLY UP TO AN INCH OR TWO IS EXPECTED...WITH
LOCALLY UP TO 3 INCHES IN THE HIGH TERRAIN OF WESTERN NEW ENGLAND
WHERE UPSLOPE WILL ALSO AID IN SQUEEZING OUT A LITTLE ADDITIONAL
SNOWFALL AS WELL.
LIGHT WINDS WILL SHIFT TO THE WEST AND INCREASE WITH THE PASSAGE
OF THE ARCTIC BOUNDARY AND MUCH COLDER AIR WILL BEGIN TO BE
USHERED ON THE REGION FOR LATE TONIGHT. THESE WINDS WILL CAUSE
SOME BLOWING OF THE SNOW. TEMPS WILL ONLY SLOWLY FALL OR NEARLY
HOLD STEADY UNTIL THE FRONT PASSES...AND THEN SHOULD REALLY BEGIN
TO FALL FAST BEHIND THE ARCTIC BOUNDARY CLOSER TO DAYBREAK. MINS
AROUND SUNRISE TOMORROW WILL BE IN THE TEENS TO LOWER 20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
TRANSITION TO LAKE EFFECT SNOWS OCCURS IN WAKE OF CLIPPER SYSTEM
AS ARCTIC AIRMASS POURS INTO REGION A BRISK AND GUSTY WESTERLY
WINDS.
HAVE HAD A CHANGE IN HEADLINES...BASED ON EXPECTED TRAJECTORY OF
THE LAKE EFFECT SNOWS WARNING CRITERIA SNOW IS NOT EXPECTED IN
NORTHERN HERKIMER COUNTY SO HAVE DOWNGRADED THE LAKE EFFECT SNOW
WARNING TO A LAKE EFFECT SNOW ADVISORY. KEPT THE TIMING THE
SAME...MONDAY THROUGH TUESDAY.
THE LAKE EFFECT SNOW WARNING REMAINS IN EFFECT FOR SOUTHERN
HERKIMER COUNTY FOR MONDAY THROUGH TUESDAY. THE NEW YORK STATE
THRUWAY WILL BE IMPACTED BY THE LAKE EFFECT SNOWS.
INITIALLY THE FLOW IN THE WAKE OF THE ARCTIC BOUNDARY WILL BE
WESTERLY...HOWEVER IT WILL SHIFT BECOMING MORE NORTHWESTERLY
DURING THE DAY. THIS WILL RESULT IN THE LAKE EFFECT SNOWS BEING
FOCUSED ACROSS CENTRAL NEW YORK INTO THE WESTERN AND CENTRAL MOHAWK
VALLEY AND INTO THE SCHOHARIE VALLEY. HAVE CONFIDENCE FOR WARNING
CRITERIA SNOWFALL IN SOUTHERN HERKIMER COUNTY. AT THIS TIME
FORECASTING 6 TO 12 INCHES WITH THE BULK OF THE SNOW FALLING
MAINLY MONDAY AFTERNOON AND EVENING...HOWEVER THE BRISK AND GUSTY
WINDS WILL CAUSING BLOWING AND DRIFTING OF THE SNOW.
ADVISORY LEVEL SNOWS ARE POSSIBLE ACROSS THE WESTERN PORTIONS OF
SCHOHARIE...MONTGOMERY AND FULTON COUNTIES. HOWEVER...CONFIDENCE
IS NOT HIGH ENOUGH AT THIS TIME TO ISSUE A LAKE EFFECT SNOW
ADVISORY...BUT ONE WILL BE ISSUE IF OUR CONFIDENCE INCREASE. HAVE
MENTION IN THE HAZARDOUS WEATHER OUTLOOK.
THE MUCH COLDER TEMPERATURES ALONG WITH THE BRISK AND GUSTY WINDS
WILL RESULT IN LOW WIND CHILL READINGS...PARTICULARLY MONDAY NIGHT
INTO TUESDAY MORNING JUST IN TIME FOR THE KIDS TO GO BACK TO
SCHOOL. BASED ON THE CURRENT TEMPERATURE AND WIND FORECAST
EXPECTING WIND CHILL READINGS OF 10 DEGREES BELOW ZERO AND COLDER
ARE EXPECTED ACROSS THE HIGHER TERRAIN AND THE MOHAWK VALLEY WITH
A WIND CHILL ADVISORY POSSIBLY BEING NEEDED ACROSS NORTHERN
HERKIMER AND HAMILTON COUNTIES. IN THE VALLEY...WIND CHILL VALUES
OF BELOW ZERO ARE EXPECTED.
TEMPERATURES AROUND 10 DEGREES BELOW NORMAL ARE EXPECTED MONDAY
THROUGH TUESDAY.
WINDS WILL REMAIN BRISK AND GUSTY THROUGH TUESDAY NIGHT. THEY WILL
BE THE STRONGEST DURING THE DAYTIME MONDAY AND TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
SOME LAKE EFFECT SNOW WILL STILL BE ONGOING ACROSS CENTRAL NEW YORK
AT THE START OF THE LONG TERM PERIOD ON WEDNESDAY MORNING. SOME OF
THESE SNOW SHOWERS AND FLURRIES MAY SNEAK THEIR WAY INTO THE WESTERN
MOHAWK VALLEY...OTHERWISE IT LOOKS TO BE MOSTLY TO PARTLY SUNNY AND
COLD ONCE AGAIN ON WEDNESDAY WITH TEMPS REACHING THE MID 20S TO LOW
30S FOR VALLEY AREAS. ANY LAKE EFFECT LOOKS TO DIMINISH IN THE
AFTERNOON HOURS....AS AN APPROACHING WEAK UPPER LEVEL SHORTWAVE WILL
HELP DISRUPT THE FLOW. THIS WEAK SHORTWAVE MAY ALLOW FOR A FEW LIGHT
SNOW SHOWERS ACROSS WESTERN AREAS ON WED NIGHT...OTHERWISE IT LOOKS
TO DRY AND COLD WITH A PARTLY TO MOSTLY CLOUDY SKY. OVERNIGHT LOWS
ON WED NIGHT WILL BE IN THE SINGLE DIGITS AND TEENS.
BEHIND THIS SYSTEM...AN AREA OF HIGH PRESSURE WILL BUILD INTO THE
REGION FOR THURSDAY. THIS HIGH PRESSURE WILL KEEP DRY CONDITIONS IN
PLACE INTO MUCH OF FRIDAY. TEMPERATURES WILL CONTINUE TO BE BELOW
NORMAL WITH HIGHS IN THE 20S...AND OVERNIGHT LOWS IN THE SINGLE
DIGITS AND TEENS.
THERE IS A GREAT AMOUNT OF UNCERTAINTY REGARDING THE FORECAST FOR
FRIDAY NIGHT INTO THE WEEKEND. A STORM SYSTEM THAT WILL BE MOVING
FROM THE MISSISSIPPI VALLEY TOWARDS THE OHIO VALLEY ON FRIDAY LOOKS
TO REDEVELOP OFF THE MID ATLANTIC COAST FOR FRI NIGHT INTO WEEKEND.
AS THIS SYSTEM THEN LIFTS NORTHEAST...THE TRACK OF THIS SYSTEM WILL
DETERMINE HOW MUCH PRECIP REACHES INTO OUR AREA. WITH COLD AIR IN
PLACE...ANY PRECIP WOULD BE IN THE FORM OF SNOW. AT THIS
POINT...AREAS SOUTH AND EAST OF THE CAPITAL REGION HAVE THE HIGHEST
CHANCE OF SEEING SOME ACCUMULATING SNOWFALL...AS THE STORMS TRACKS
OFF THE EASTERN SEABOARD.
MODEL SCENARIOS ARE STILL ALL OVER THE PLACE WITH QPF AMOUNTS...AND
THERE IS A LARGE SPREAD IN THE GEFS MEMBERS AS WELL. THE LATEST 12Z
GFS WOULD SUGGEST LITTLE TO SNOW FALLS IN THE ALBANY AREA...ALTHOUGH
THE 12Z ECMWF/GGEM WOULD HAVE MORE OF AN IMPACT FOR MUCH OF THE CWA.
IN ADDITION...THERE IS ALSO UNCERTAINTY WITH THE EXACT
TIMING/DURATION OF ANY POTENTIAL EVENT AS WELL. WITH THIS EVENT
STILL BEING ALMOST A WEEK AWAY...THIS UNCERTAINTY IS EXPECTED...AND
HOPEFULLY MODEL/ENSEMBLE GUIDANCE WILL HELP NARROW THE WINDOW OF
SOLUTIONS DURING THE UPCOMING WEEK. FOR NOW...WILL GO WITH CHC POPS
FOR SNOW FOR SOUTHERN AREAS...AND SLIGHT CHC FOR FURTHER NORTH.
TEMPS WILL CONTINUE TO BE MAINLY IN THE 20S FOR HIGHS...AND TEENS AT
NIGHT.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
FLYING CONDITIONS ARE CURRENTLY VFR WITH LIGHT WINDS AND BKN-OVC
CIGS AROUND 5-9 KFT. HOWEVER...AN APPROACHING CLIPPER SYSTEM WILL
ALLOW FOR SOME LIGHT SNOW SHOWERS/FLURRIES TO BEGIN WITHIN THE
NEXT FEW HOURS. FLYING CONDITIONS WILL DROP TO MVFR IN THE NEXT
COUPLE OF HOURS AND A PERIOD OF IFR DUE TO VSBYS /AND POSSIBLY
CIGS TOO/ LOOKS TO OCCUR FOR THE LATE NIGHT HOURS WITH A PERIOD OF
LIGHT SNOWFALL. THE EXCEPTION WILL BE AT KPOU WHERE CIGS AND VSBYS
WILL REMAIN VFR. IN ADDITION...WINDS WILL BECOME WESTERLY AND
INCREASE TO AROUND 10 KTS WITH SOME HIGHER GUSTS BY LATE TONIGHT
BEHIND THE ARCTIC COLD FRONT AS WELL. STEADY SNOW SHOULD TAPER OFF
BY AROUND DAYBREAK MONDAY...ALLOWING FLYING CONDITIONS TO RETURN
TO MVFR AND EVENTUALLY VFR CONDITIONS.
MAINLY VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY MONDAY.
CIGS LOOK TO BE BKN-OVC AT 4-6 KFT DUE TO LEFTOVER CLOUDS FROM
LAKE EFFECT SNOW TO THE WEST...BUT ANY OF THE SNOW SHOWER ACTIVITY
LOOKS TO REMAIN MAINLY WEST OF THE REGION. IT WILL CONTINUE TO BE
WINDY...WITH W-NW WINDS AT 10-15 KTS...AND SOME GUSTS UP TO 25 KTS
AT TIMES...ESP FOR KALB/KPSF.
OUTLOOK...
MON NIGHT: LOW OPERATIONAL IMPACT. BRISK. SLIGHT CHANCE OF SHSN.
TUE: MODERATE OPERATIONAL IMPACT. WINDY. SLIGHT CHANCE OF SHSN.
TUE NIGHT: LOW OPERATIONAL IMPACT. BRISK.
WED: NO OPERATIONAL IMPACT. NO SIG WX.
WED NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THU: NO OPERATIONAL IMPACT. NO SIG WX.
THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRI: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
COLDER AIR RETURNS TO THE HSA AND WILL PERSIST THROUGH THE
UPCOMING WEEK. PRECIPITATION TYPE WILL BE SNOW. ICE WILL FORM ON
BODIES OF WATER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST
TUESDAY FOR NYZ032.
WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ032-033.
LAKE EFFECT SNOW WARNING FROM 6 AM THIS MORNING TO 6 PM EST
TUESDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/FRUGIS/KL
SHORT TERM...IAA
LONG TERM...FRUGIS
AVIATION...FRUGIS/11
HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1216 AM EST MON JAN 18 2016
.SYNOPSIS...
A QUICK MOVING...CLIPPER...LOW PRESSURE SYSTEM WILL APPROACH
AND WILL MOVE ACROSS THE REGION TONIGHT BRINGING MAINLY A LIGHT
SNOWFALL TO THE AREA. IN THE WAKE OF THIS SYSTEM...AN ARCTIC
AIRMASS WILL BE USHERED IN ON BRISK AND GUSTY WESTERLY WINDS.
TEMPERATURES MONDAY NIGHT WILL DROP INTO THE SINGLE DIGITS AND
BELOW ZERO ACROSS MUCH OF THE LOCAL AREA. LAKE EFFECT SNOWS WILL
DEVELOP DOWNWIND OF LAKE ONTARIO MONDAY MORNING AND WILL PERSIST
THROUGH TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 932 PM EST...A FAST MOVING CLIPPER SYSTEM IS HEADED TOWARDS
THE AREA FOR TONIGHT. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM
IS NOW LOCATED OVER CENTRAL NY AND WILL BE APPROACHING OUR WESTERN
AREAS VERY SOON. SOME AREAS OF LIGHT SNOW AND SNOW SHOWERS HAS
ALREADY BROKEN OUT ACROSS THE MOHAWK VALLEY AND WESTERN
ADIRONDACKS...AND SOME ADDITIONAL SNOW SHOWERS HAVE ALSO ALREADY
OCCURRED OVER WESTERN NEW ENGLAND AS WELL THANKS TO A DEPARTING
COASTAL WAVE.
THE MOST HEAVIEST SNOW SHOWERS UPSTREAM ARE OVER THE EASTERN END
OF LAKE ONTARIO...AND THESE SNOW SHOWERS...AIDED BY SOME
MOISTURE/INSTABILITY THANKS TO LAKE ONTARIO...WILL BE MOVING INTO
OUR WESTERN ADIRONDACKS OVER THE NEXT FEW HOURS. THESE SNOW
SHOWERS WILL HAVE THE CAPABILITY OF DROPPING A QUICK INCH OR TWO
WITHIN A 60-90 MINUTE PERIOD.
FURTHER SOUTH...THE 01Z 3KM HRRR SUGGEST THAT AREAS OF LIGHT SNOW
WITH SOME HEAVIER EMBEDDED BURSTS WILL CONTINUE TO MOVE ACROSS
THE AREA DURING THE OVERNIGHT HOURS /MAINLY AFTER MIDNIGHT/ AS THE
CLIPPER SYSTEM MOVES THROUGH. THERE COULD BE A LOCALIZED SQUALL
RIGHT ALONG WITH THE PASSAGE OF THE CLIPPER/S COLD FRONT TONIGHT...WITH
A BRIEF BURST OF HEAVY SNOW...GUSTY WINDS AND LOW VISIBILITY. ANY
SQUALL WILL BE VERY SHORT IN DURATION...AND SHOULD BE LIMITED
IMPACT DUE TO IT/S OCCURRING IN THE MIDDLE OF THE NIGHT.
STILL...ANY OVERNIGHT TRAVELERS SHOULD BE AWARE THAT THE WEATHER
WILL BE LESS THAN IDEAL FOR DRIVING LATE TONIGHT.
A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR NORTHERN HERKIMER
AND HAMILTON COUNTIES...WHERE THE BEST QPF IS EXPECTED TO
OCCUR...AND SOME LAKE ENHANCEMENT/UPSLOPE WILL AID IN ALLOWING
SNOWFALL TOTALS OVERNIGHT TO BE AROUND 2-6 INCHES.
ELSEWHERE...GENERALLY UP TO AN INCH OR TWO IS EXPECTED...WITH
LOCALLY UP TO 3 INCHES IN THE HIGH TERRAIN OF WESTERN NEW ENGLAND
WHERE UPSLOPE WILL ALSO AID IN SQUEEZING OUT A LITTLE ADDITIONAL
SNOWFALLAS WELL.
LIGHT WINDS WILL SHIFT TO THE WEST AND INCREASE WITH THE PASSAGE
OF THE ARCTIC BOUNDARY AND MUCH COLDER AIR WILL BEGIN TO BE
USHERED ON THE REGION FOR LATE TONIGHT. THESE WINDS WILL CAUSE
SOME BLOWING OF THE SNOW. TEMPS WILL ONLY SLOWLY FALL OR NEARLY
HOLD STEADY THROUGH THE LATE EVENING...BUT SHOULD REALLY BEGIN TO
FALL FAST BEHIND THE ARCTIC BOUNDARY FOR LATE TONIGHT. MINS AROUND
SUNRISE TOMORROW WILL BE IN THE TEENS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
TRANSITION TO LAKE EFFECT SNOWS OCCURS IN WAKE OF CLIPPER SYSTEM
AS ARCTIC AIRMASS POURS INTO REGION A BRISK AND GUSTY WESTERLY
WINDS.
HAVE HAD A CHANGE IN HEADLINES...BASED ON EXPECTED TRAJECTORY OF
THE LAKE EFFECT SNOWS WARNING CRITERIA SNOW IS NOT EXPECTED IN
NORTHERN HERKIMER COUNTY SO HAVE DOWNGRADED THE LAKE EFFECT SNOW
WARNING TO A LAKE EFFECT SNOW ADVISORY. KEPT THE TIMING THE
SAME...MONDAY THROUGH TUESDAY.
THE LAKE EFFECT SNOW WARNING REMAINS IN EFFECT FOR SOUTHERN
HERKIMER COUNTY FOR MONDAY THROUGH TUESDAY. THE NEW YORK STATE
THRUWAY WILL BE IMPACTED BY THE LAKE EFFECT SNOWS.
INITIALLY THE FLOW IN THE WAKE OF THE ARCTIC BOUNDARY WILL BE
WESTERLY...HOWEVER IT WILL SHIFT BECOMING MORE NORTHWESTERLY
DURING THE DAY. THIS WILL RESULT IN THE LAKE EFFECT SNOWS BEING
FOCUSED ACROSS CENTRAL NEW YORK INTO THE WESTERN AND CENTRAL MOHAWK
VALLEY AND INTO THE SCHOHARIE VALLEY. HAVE CONFIDENCE FOR WARNING
CRITERIA SNOWFALL IN SOUTHERN HERKIMER COUNTY. AT THIS TIME
FORECASTING 6 TO 12 INCHES WITH THE BULK OF THE SNOW FALLING
MAINLY MONDAY AFTERNOON AND EVENING...HOWEVER THE BRISK AND GUSTY
WINDS WILL CAUSING BLOWING AND DRIFTING OF THE SNOW.
ADVISORY LEVEL SNOWS ARE POSSIBLE ACROSS THE WESTERN PORTIONS OF
SCHOHARIE...MONTGOMERY AND FULTON COUNTIES. HOWEVER...CONFIDENCE
IS NOT HIGH ENOUGH AT THIS TIME TO ISSUE A LAKE EFFECT SNOW
ADVISORY...BUT ONE WILL BE ISSUE IF OUR CONFIDENCE INCREASE. HAVE
MENTION IN THE HAZARDOUS WEATHER OUTLOOK.
THE MUCH COLDER TEMPERATURES ALONG WITH THE BRISK AND GUSTY WINDS
WILL RESULT IN LOW WIND CHILL READINGS...PARTICULARLY MONDAY NIGHT
INTO TUESDAY MORNING JUST IN TIME FOR THE KIDS TO GO BACK TO
SCHOOL. BASED ON THE CURRENT TEMPERATURE AND WIND FORECAST
EXPECTING WIND CHILL READINGS OF 10 DEGREES BELOW ZERO AND COLDER
ARE EXPECTED ACROSS THE HIGHER TERRAIN AND THE MOHAWK VALLEY WITH
A WIND CHILL ADVISORY POSSIBLY BEING NEEDED ACROSS NORTHERN
HERKIMER AND HAMILTON COUNTIES. IN THE VALLEY...WIND CHILL VALUES
OF BELOW ZERO ARE EXPECTED.
TEMPERATURES AROUND 10 DEGREES BELOW NORMAL ARE EXPECTED MONDAY
THROUGH TUESDAY.
WINDS WILL REMAIN BRISK AND GUSTY THROUGH TUESDAY NIGHT. THEY WILL
BE THE STRONGEST DURING THE DAYTIME MONDAY AND TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
SOME LAKE EFFECT SNOW WILL STILL BE ONGOING ACROSS CENTRAL NEW YORK
AT THE START OF THE LONG TERM PERIOD ON WEDNESDAY MORNING. SOME OF
THESE SNOW SHOWERS AND FLURRIES MAY SNEAK THEIR WAY INTO THE WESTERN
MOHAWK VALLEY...OTHERWISE IT LOOKS TO BE MOSTLY TO PARTLY SUNNY AND
COLD ONCE AGAIN ON WEDNESDAY WITH TEMPS REACHING THE MID 20S TO LOW
30S FOR VALLEY AREAS. ANY LAKE EFFECT LOOKS TO DIMINISH IN THE
AFTERNOON HOURS....AS AN APPROACHING WEAK UPPER LEVEL SHORTWAVE WILL
HELP DISRUPT THE FLOW. THIS WEAK SHORTWAVE MAY ALLOW FOR A FEW LIGHT
SNOW SHOWERS ACROSS WESTERN AREAS ON WED NIGHT...OTHERWISE IT LOOKS
TO DRY AND COLD WITH A PARTLY TO MOSTLY CLOUDY SKY. OVERNIGHT LOWS
ON WED NIGHT WILL BE IN THE SINGLE DIGITS AND TEENS.
BEHIND THIS SYSTEM...AN AREA OF HIGH PRESSURE WILL BUILD INTO THE
REGION FOR THURSDAY. THIS HIGH PRESSURE WILL KEEP DRY CONDITIONS IN
PLACE INTO MUCH OF FRIDAY. TEMPERATURES WILL CONTINUE TO BE BELOW
NORMAL WITH HIGHS IN THE 20S...AND OVERNIGHT LOWS IN THE SINGLE
DIGITS AND TEENS.
THERE IS A GREAT AMOUNT OF UNCERTAINTY REGARDING THE FORECAST FOR
FRIDAY NIGHT INTO THE WEEKEND. A STORM SYSTEM THAT WILL BE MOVING
FROM THE MISSISSIPPI VALLEY TOWARDS THE OHIO VALLEY ON FRIDAY LOOKS
TO REDEVELOP OFF THE MID ATLANTIC COAST FOR FRI NIGHT INTO WEEKEND.
AS THIS SYSTEM THEN LIFTS NORTHEAST...THE TRACK OF THIS SYSTEM WILL
DETERMINE HOW MUCH PRECIP REACHES INTO OUR AREA. WITH COLD AIR IN
PLACE...ANY PRECIP WOULD BE IN THE FORM OF SNOW. AT THIS
POINT...AREAS SOUTH AND EAST OF THE CAPITAL REGION HAVE THE HIGHEST
CHANCE OF SEEING SOME ACCUMULATING SNOWFALL...AS THE STORMS TRACKS
OFF THE EASTERN SEABOARD.
MODEL SCENARIOS ARE STILL ALL OVER THE PLACE WITH QPF AMOUNTS...AND
THERE IS A LARGE SPREAD IN THE GEFS MEMBERS AS WELL. THE LATEST 12Z
GFS WOULD SUGGEST LITTLE TO SNOW FALLS IN THE ALBANY AREA...ALTHOUGH
THE 12Z ECMWF/GGEM WOULD HAVE MORE OF AN IMPACT FOR MUCH OF THE CWA.
IN ADDITION...THERE IS ALSO UNCERTAINTY WITH THE EXACT
TIMING/DURATION OF ANY POTENTIAL EVENT AS WELL. WITH THIS EVENT
STILL BEING ALMOST A WEEK AWAY...THIS UNCERTAINTY IS EXPECTED...AND
HOPEFULLY MODEL/ENSEMBLE GUIDANCE WILL HELP NARROW THE WINDOW OF
SOLUTIONS DURING THE UPCOMING WEEK. FOR NOW...WILL GO WITH CHC POPS
FOR SNOW FOR SOUTHERN AREAS...AND SLIGHT CHC FOR FURTHER NORTH.
TEMPS WILL CONTINUE TO BE MAINLY IN THE 20S FOR HIGHS...AND TEENS AT
NIGHT.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
FLYING CONDITIONS ARE CURRENTLY VFR WITH LIGHT WINDS AND BKN-OVC
CIGS AROUND 5-9 KFT. HOWEVER...AN APPROACHING CLIPPER SYSTEM WILL
ALLOW FOR SOME LIGHT SNOW SHOWERS/FLURRIES TO BEGIN WITHIN THE
NEXT FEW HOURS. FLYING CONDITIONS WILL DROP TO MVFR IN THE NEXT
COUPLE OF HOURS AND A PERIOD OF IFR DUE TO VSBYS /AND POSSIBLY
CIGS TOO/ LOOKS TO OCCUR FOR THE LATE NIGHT HOURS WITH A PERIOD OF
LIGHT SNOWFALL. THE EXCEPTION WILL BE AT KPOU WHERE CIGS AND VSBYS
WILL REMAIN VFR. IN ADDITION...WINDS WILL BECOME WESTERLY AND
INCREASE TO AROUND 10 KTS WITH SOME HIGHER GUSTS BY LATE TONIGHT
BEHIND THE ARCTIC COLD FRONT AS WELL. STEADY SNOW SHOULD TAPER OFF
BY AROUND DAYBREAK MONDAY...ALLOWING FLYING CONDITIONS TO RETURN
TO MVFR AND EVENTUALLY VFR CONDITIONS.
MAINLY VFR CONDITIONS ARE EXPECTED THROUGHOUT THE DAY MONDAY.
CIGS LOOK TO BE BKN-OVC AT 4-6 KFT DUE TO LEFTOVER CLOUDS FROM
LAKE EFFECT SNOW TO THE WEST...BUT ANY OF THE SNOW SHOWER ACTIVITY
LOOKS TO REMAIN MAINLY WEST OF THE REGION. IT WILL CONTINUE TO BE
WINDY...WITH W-NW WINDS AT 10-15 KTS...AND SOME GUSTS UP TO 25 KTS
AT TIMES...ESP FOR KALB/KPSF.
OUTLOOK...
MON NIGHT: LOW OPERATIONAL IMPACT. BRISK. SLIGHT CHANCE OF SHSN.
TUE: MODERATE OPERATIONAL IMPACT. WINDY. SLIGHT CHANCE OF SHSN.
TUE NIGHT: LOW OPERATIONAL IMPACT. BRISK.
WED: NO OPERATIONAL IMPACT. NO SIG WX.
WED NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THU: NO OPERATIONAL IMPACT. NO SIG WX.
THU NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
FRI: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.HYDROLOGY...
COLDER AIR RETURNS TO THE HSA AND WILL PERSIST THROUGH THE
UPCOMING WEEK. PRECIPITATION TYPE WILL BE SNOW. ICE WILL FORM ON
BODIES OF WATER.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST
TUESDAY FOR NYZ032.
WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ032-033.
LAKE EFFECT SNOW WARNING FROM 6 AM THIS MORNING TO 6 PM EST
TUESDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/FRUGIS
SHORT TERM...IAA
LONG TERM...FRUGIS
AVIATION...FRUGIS/11
HYDROLOGY...IAA
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
249 PM CST MON JAN 18 2016
.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST MON JAN 18 2016
A robust diurnal CU-field developed across central Illinois this
afternoon, mainly along and south of the I-72 corridor. Meanwhile,
a persistent band of low clouds extending from Minnesota into west-
central Illinois tried to push eastward, but generally stayed west
of a Macomb to Jacksonville line. The diurnal clouds will rapidly
dissipate toward sunset: however, the band of clouds further west
will likely persist into the evening. Models have not been picking
up on these clouds at all, with the HRRR 1-hour forecast suggesting
clear skies. Based on satellite loops, think they will inch
eastward into the Illinois River Valley over the next couple of
hours before gradually dissipating later in the evening. Will need
to monitor satellite trends closely to see if they spread further or
persist longer. At this time, will only bring them to a Galesburg
to just west of Springfield line this evening. Elsewhere, skies
will remain mostly clear through the night. Overnight low
temperatures will be in the single digits above zero across most of
the area, but will likely drop a couple degrees below zero across
the far north around Galesburg and Lacon.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 248 PM CST MON JAN 18 2016
Arctic high pressure area will shift east of the CWA Tuesday and
allow a developing weather system in the southern plains to push
east and bring precip back into the area beginning late Tue
afternoon and continuing through Tue night, then ending Wed morning.
Temps thru the period will be cold enough for all snow, so question
will be how much snow and when will heaviest snow occur. The models
have trended slightly slower with the onset of the snow and this
makes sense given the current dryness of the lower layers and the
expected southeast winds tomorrow not bringing any moisture into the
area. So, believe snow will begin over most of the area after 6pm
tomorrow evening, though some light snow may begin in western IL
late tomorrow afternoon. Heaviest snowfall track should be from the
Jacksonville area to southeast IL, tomorrow evening through after
midnight. The main low will be tracking into AR late tomorrow night,
but system should be able to spread enough pcpn north into the area.
Models indicate good isentropic lift with this system with around
3g/kg of moisture being lifted. However, factors limiting the amount
of snowfall will be lack of low level moisture initially, system
will be weakening as it moves east, and system will be moving
through quickly. So snowfall thinking is 3-4 inches in western IL
will be the highest, decreasing to around 3 inches in the southeast,
and 2 to 2.5 inches along I-74. This matches up well with other
offices and thinking of the WWD graphics. Snow will continue into
Wed morning,but only in the east and southeastern parts of the CWA.
1/2 inch will still be possible in the Lawrenceville area before
ending by noon. Advisory will be likely in some part of the CWA, but
given most of the snow will be third period and still some
uncertainty on strength of system, will let overnight shift make
final decision on location of advisory.
A period of dry weather is then expected Wed night through Thursday
as this system pushes east and then next system moves out of the
plains toward the area. All models have finally come to some
agreement on the track of this next system and it appears that most
of the pcpn with it will be south of the CWA. Current forecasts show
that a chance of snow is possible in southeast IL Thur night only.
Otherwise, dry weather can be expected from Fri into Sunday. Then
Sunday night and Monday, models show a clipper system moving across
the northern third of the state. This will bring another shot of
pcpn to the northern/northeaster/and eastern parts of the CWA. P-
type will likely be snow, but with temps being above freezing during
the daytime periods, rain, or a mix of rain and snow is not out of
the question.
Temps will remain cold through Fri night given the continued Arctic
air over the area through tomorrow and then the clouds and pcpn
expected tomorrow night through Wed, and then again being north of
the Thur night/Fri weather system. Over the weekend the pattern will
become somewhat zonal and this should allow temps to warm back up to
normal or just above normal for Sun and Mon.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1150 AM CST MON JAN 18 2016
Diurnal clouds continue to develop across central Illinois late
this morning as per the NAM CU-rule forecast. While forecast
soundings do not have a particularly good handle on the cloud
level, area obs are generally showing around 2500ft. Have
occasionally seen a BKN ceiling: however, think these will be
fleeting and did not include in the TAFs. Have instead gone with
SCT025 at all terminals through the afternoon. Will continue to
monitor a more significant band of VFR clouds stretching from
Minnesota into west-central Illinois to see if they could possibly
shift eastward and impact KSPI. Latest satellite loops are
beginning to show the cloud area shrinking, so do not think they
will get much further eastward. Once any diurnal clouds dissipate
toward sunset, skies will be mostly clear tonight before the next
system begins approaching from the west Tuesday morning. NAM
forecast soundings suggest VFR clouds of 8000 to 10000ft arriving
at KSPI/KDEC after 15/16z...then further northeast to the
remaining TAF sites by early afternoon.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Barnes
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1150 AM CST MON JAN 18 2016
.UPDATE...
ISSUED AT 1050 AM CST MON JAN 18 2016
Very cold weather continues across central Illinois this morning,
with 16z/10am temperatures mainly in the single digits above zero.
Thanks to a ridge of high pressure approaching from the west,
winds are much lighter than they were yesterday...but are still
blowing at around 10mph. This is creating wind-chill values of 5
below to 15 below zero. As temperatures slowly warm and winds
remain light, wind-chills will rise above advisory criteria by
midday. As a result, will allow the Wind Chill Advisory to expire
at 11am. Sunny skies prevail across the area this morning,
although diurnal clouds are beginning to develop along/south of
I-72 and a persistent patch of low clouds extending from
Minnesota southward into west-central Illinois is nudging its way
eastward. Models are not handling this cloud area very well at
all, with the HRRR showing clear skies. Based on satellite loops,
have increased sky cover across the far SW CWA along/southwest of
a Rushville to Jacksonville line to feature a period of partly to
mostly cloudy conditions from late morning into early afternoon.
Current thinking is that these clouds will gradually dissipate as
the day progresses, but will need to keep an eye on their progress
to see how far eastward they spread.
&&
.SHORT TERM...(Today)
ISSUED AT 335 AM CST MON JAN 18 2016
A Wind Chill Advisory will continue across central Illinois and
parts of southeast Illinois this morning. However, even where the
advisory is not in effect, it will still be very cold. Arctic high
pressure will continue to spread across the Midwest today. However,
by midday, it will feel just a touch less cold across most of the
forecast area. The upper level trof axis, and core of the cold air,
will continue to pull away from the area today. This fact, and
decreasing surface winds due to the approach of the surface ridge
axis, will allow Wind Chill values to moderate a bit from the values
seen late yesterday and through the night.
Aside from the cold, the only other weather concern today is the
potential for more clouds by afternoon. An area of low clouds lies
along the surface ridge axis from the upper Midwest into the
northern Plains. The model guidance is not too bullish overall on
these clouds working into the area. However, their current track on
satellite suggests at least the western portion of the forecast area
my be somewhat cloudier later today than current forecast. Have
bumped up sky cover later today to account for this potential, but
the coverage may need to be boosted further if trends persist.
.LONG TERM...(Tonight through Sunday)
ISSUED AT 335 AM CST MON JAN 18 2016
1033 mb Canadian high pressure over eastern KS and western MO and
ridging northward to along the MN and Dakotas border, will drift
east into IL by Tue morning. This will bring another frigid night to
central and southeast IL with fair skies, though lighter WSW winds
tonight will keep wind chills from reaching wind chill advisory
criteria of -15F. Coldest wind chills northern CWA tonight around 10
below zero. Lows tonight range from near zero northern CWA to 4-7F
sw CWA and southeast IL.
Clouds to increase from sw to ne across central IL during the day
Tue ahead of a weather system moving into the Great Plains. 00Z
models have trended a bit quicker spreading chances of light snow
into western/sw CWA Tue afternoon though think drier air will
initially be virga. Increase chances of light snow to 30-50% from
Canton to Springfield west by mid/late Tue afternoon. Highs Tue
range from around 20F northern CWA to near 25F far southern CWA
along and south of highway 50.
A mid level trof to move east into IL by 12Z Wed while weak surface
low pressure moves across northern OK/AR. Increasing isentropic lift
ahead of this feature over IL Tue night to spread snow eastward
across the area during Tue evening and continue overnight Tue night.
The snow to diminish from west to east during Wed morning. Total qpf
around a quarter inch while snow ratios are 12-15:1 and supports a 2-
4 inch snow fall with locally 4-5 inches sw CWA. Mixed precipitation
should stay south of our CWA. A winter weather advisory will likely
be needed across area Tue night into Wed morning for these snowfall
accumulations with slippery roads likely for Wed morning commute.
Temps modify Wed with highs in upper 20s central IL and lower 30s in
southeast IL which is still a bit cooler than normal.
00Z GFS, GEM and ECMWF models show a southern stream storm system
moving across the Gulf Coast/Southeast States Thu/Fri and keeping
brunt of its qpf southeast of central IL and brushing far southeast
IL. This storm system will have more gulf moisture to work with and
heavier qpf expected to still pass south/se of IL. Have chance pops
of light snow southeast IL Thu night and Fri morning while slight
chances central areas and dry over IL river valley. Could see mix
precipitation along and south of highway 50. Models have not been as
consistent with this storm system for past few model runs so less
confidence in forecast late this work week. Highs Thu/Fri in the
upper 20s and lower 30s with mildest readings in southeast IL.
Upper level ridge shifts east toward IL on Saturday and ohio river
valley Sunday and to bring with milder temperatures especially on
Sunday with highs 35-40F. Have small chances of light rain/snow from
Sunday afternoon through Monday due to warm air advection, though
models differ on this solution and amounts of qpf. Stayed close to
consensus for pops and temperatures early next week. CPC 8-14 day
outlook for last week of Jan 25-31 has great than normal chances of
above normal temperatures across the country, with IL having 60-65%
chance of above normal temperatures.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1150 AM CST MON JAN 18 2016
Diurnal clouds continue to develop across central Illinois late
this morning as per the NAM CU-rule forecast. While forecast
soundings do not have a particularly good handle on the cloud
level, area obs are generally showing around 2500ft. Have
occasionally seen a BKN ceiling: however, think these will be
fleeting and did not include in the TAFs. Have instead gone with
SCT025 at all terminals through the afternoon. Will continue to
monitor a more significant band of VFR clouds stretching from
Minnesota into west-central Illinois to see if they could possibly
shift eastward and impact KSPI. Latest satellite loops are
beginning to show the cloud area shrinking, so do not think they
will get much further eastward. Once any diurnal clouds dissipate
toward sunset, skies will be mostly clear tonight before the next
system begins approaching from the west Tuesday morning. NAM
forecast soundings suggest VFR clouds of 8000 to 10000ft arriving
at KSPI/KDEC after 15/16z...then further northeast to the
remaining TAF sites by early afternoon.
&&
.ILX Watches/Warnings/Advisories...
NONE.
&&
$$
UPDATE...Barnes
SHORT TERM...BAK
LONG TERM...07
AVIATION...Barnes
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1050 AM CST MON JAN 18 2016
.UPDATE...
ISSUED AT 1050 AM CST MON JAN 18 2016
Very cold weather continues across central Illinois this morning,
with 16z/10am temperatures mainly in the single digits above zero.
Thanks to a ridge of high pressure approaching from the west,
winds are much lighter than they were yesterday...but are still
blowing at around 10mph. This is creating wind-chill values of 5
below to 15 below zero. As temperatures slowly warm and winds
remain light, wind-chills will rise above advisory criteria by
midday. As a result, will allow the Wind Chill Advisory to expire
at 11am. Sunny skies prevail across the area this morning,
although diurnal clouds are beginning to develop along/south of
I-72 and a persistent patch of low clouds extending from
Minnesota southward into west-central Illinois is nudging its way
eastward. Models are not handling this cloud area very well at
all, with the HRRR showing clear skies. Based on satellite loops,
have increased sky cover across the far SW CWA along/southwest of
a Rushville to Jacksonville line to feature a period of partly to
mostly cloudy conditions from late morning into early afternoon.
Current thinking is that these clouds will gradually dissipate as
the day progresses, but will need to keep an eye on their progress
to see how far eastward they spread.
&&
.SHORT TERM...(Today)
ISSUED AT 335 AM CST MON JAN 18 2016
A Wind Chill Advisory will continue across central Illinois and
parts of southeast Illinois this morning. However, even where the
advisory is not in effect, it will still be very cold. Arctic high
pressure will continue to spread across the Midwest today. However,
by midday, it will feel just a touch less cold across most of the
forecast area. The upper level trof axis, and core of the cold air,
will continue to pull away from the area today. This fact, and
decreasing surface winds due to the approach of the surface ridge
axis, will allow Wind Chill values to moderate a bit from the values
seen late yesterday and through the night.
Aside from the cold, the only other weather concern today is the
potential for more clouds by afternoon. An area of low clouds lies
along the surface ridge axis from the upper Midwest into the
northern Plains. The model guidance is not too bullish overall on
these clouds working into the area. However, their current track on
satellite suggests at least the western portion of the forecast area
my be somewhat cloudier later today than current forecast. Have
bumped up sky cover later today to account for this potential, but
the coverage may need to be boosted further if trends persist.
.LONG TERM...(Tonight through Sunday)
ISSUED AT 335 AM CST MON JAN 18 2016
1033 mb Canadian high pressure over eastern KS and western MO and
ridging northward to along the MN and Dakotas border, will drift
east into IL by Tue morning. This will bring another frigid night to
central and southeast IL with fair skies, though lighter WSW winds
tonight will keep wind chills from reaching wind chill advisory
criteria of -15F. Coldest wind chills northern CWA tonight around 10
below zero. Lows tonight range from near zero northern CWA to 4-7F
sw CWA and southeast IL.
Clouds to increase from sw to ne across central IL during the day
Tue ahead of a weather system moving into the Great Plains. 00Z
models have trended a bit quicker spreading chances of light snow
into western/sw CWA Tue afternoon though think drier air will
initially be virga. Increase chances of light snow to 30-50% from
Canton to Springfield west by mid/late Tue afternoon. Highs Tue
range from around 20F northern CWA to near 25F far southern CWA
along and south of highway 50.
A mid level trof to move east into IL by 12Z Wed while weak surface
low pressure moves across northern OK/AR. Increasing isentropic lift
ahead of this feature over IL Tue night to spread snow eastward
across the area during Tue evening and continue overnight Tue night.
The snow to diminish from west to east during Wed morning. Total qpf
around a quarter inch while snow ratios are 12-15:1 and supports a 2-
4 inch snow fall with locally 4-5 inches sw CWA. Mixed precipitation
should stay south of our CWA. A winter weather advisory will likely
be needed across area Tue night into Wed morning for these snowfall
accumulations with slippery roads likely for Wed morning commute.
Temps modify Wed with highs in upper 20s central IL and lower 30s in
southeast IL which is still a bit cooler than normal.
00Z GFS, GEM and ECMWF models show a southern stream storm system
moving across the Gulf Coast/Southeast States Thu/Fri and keeping
brunt of its qpf southeast of central IL and brushing far southeast
IL. This storm system will have more gulf moisture to work with and
heavier qpf expected to still pass south/se of IL. Have chance pops
of light snow southeast IL Thu night and Fri morning while slight
chances central areas and dry over IL river valley. Could see mix
precipitation along and south of highway 50. Models have not been as
consistent with this storm system for past few model runs so less
confidence in forecast late this work week. Highs Thu/Fri in the
upper 20s and lower 30s with mildest readings in southeast IL.
Upper level ridge shifts east toward IL on Saturday and ohio river
valley Sunday and to bring with milder temperatures especially on
Sunday with highs 35-40F. Have small chances of light rain/snow from
Sunday afternoon through Monday due to warm air advection, though
models differ on this solution and amounts of qpf. Stayed close to
consensus for pops and temperatures early next week. CPC 8-14 day
outlook for last week of Jan 25-31 has great than normal chances of
above normal temperatures across the country, with IL having 60-65%
chance of above normal temperatures.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 546 AM CST MON JAN 18 2016
VFR conditions should prevail across the central Illinois
terminals through the 12Z TAF valid time. The one fly in the
ointment is an area of low clouds streaming southeast from the
upper Midwest and Northern Plains. These clouds are not especially
well handled by the forecast guidance, but satellite extrapolation
suggests at least KPIA and KSPI may be impacted by these clouds.
While this deck is predominantly VFR, some stations beneath these
clouds are reporting MVFR conditions. Northwest winds will trend
light/variable tonight as a ridge of high pressure begins to cross
the area.
&&
.ILX Watches/Warnings/Advisories...
Wind Chill Advisory until 11 AM CST this morning for ILZ027>031-
036>038-040>057-061>063-066.
&&
$$
UPDATE...Barnes
SHORT TERM...BAK
LONG TERM...07
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
315 AM EST MON JAN 18 2016
.UPDATE...
AVIATION AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 342 PM EST SUN JAN 17 2016
COLD ARCTIC HIGH PRESSURE IN THE WAKE OF A FRONT WILL BRING VERY
COLD CONDITIONS TO THE AREA TONIGHT INTO EARLY TUESDAY. THE
COLDEST NIGHT WILL BE TONIGHT WITH WIND CHILLS LIKELY TO APPROACH
15 TO 20 BELOW ACROSS CENTRAL AND NORTHERN PORTIONS OF CENTRAL
INDIANA. DRY WEATHER CAN BE EXPECTED THROUGH TUESDAY UNDER THE
INFLUENCE OF THIS HIGH. A WEAK LOW PRESSURE SYSTEM WILL PUSH
THROUGH THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...WHICH WILL
BRING ANOTHER ROUND OF LIGHT SNOW ACCUMULATIONS TO THE AREA.
ADDITIONAL LIGHT ACCUMULATIONS WILL BE POSSIBLE LATER IN THE WEEK
AS WELL.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1139 PM EST SUN JAN 17 2016
A BAND OF LIGHT SNOW SHOWERS IS EVIDENT ON RADAR SOUTH OF
INDIANAPOLIS. WHILE SATELLITE PRODUCTS ARE NOT PICKING UP ANY
CLOUD COVER...OBSERVATIONS ARE SHOWING THE DEVELOPMENT OF CLOUDS
AROUND 1500-3000 FT. RADAR WILL BE OVERSHOOTING ANY FLURRIES
AROUND THE OUTER EDGES OF THE FORECAST AREA...AND SEE THIS
CURRENTLY OVER LAWRENCEVILLE WHERE FLURRIES ARE BEING REPORTED
BUT NO ECHOES APPARENT ON RADAR. THIS DEVELOPMENT IS LIKELY DUE TO
STEEP LAPSE RATES ACROSS THE AREA. RAP SHOWS THESE LOW LEVEL LAPSE
RATES REMAINING IN THE 8 TO 9C RANGE ACROSS THE AREA THROUGH
AROUND 7-8Z. THUS HAVE ADDED PARTLY CLOUDY SKIES AND SCATTERED
FLURRIES ACROSS THE ENTIRE AREA FOR THE NEXT FEW HOURS AS
DEVELOPMENT OF CLOUDS AND FLURRIES COULD OCCUR ANYWHERE DURING
THIS TIME. STARTING AROUND 8Z IN THE RAP LAPSE RATES RETURN TO
MORE STABLE LEVELS AND SHOULD SEE AN END TO ANY FLURRIES AND
EXPECT ANY CLOUDS TO CLEAR THEN.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 342 PM EST SUN JAN 17 2016
DRY WEATHER WILL PERSIST THROUGH TUESDAY AFTERNOON AS ARCTIC HIGH
SLIDES ACROSS THE AREA. WEAK LOW PRESSURE SYSTEM WILL SLIDE ACROSS
THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...AND LIGHT SNOW
ACCUMULATIONS APPEAR A GOOD POSSIBILITY.
ALL MODEL INDICATIONS POINT TO A SOLID BUT UNSPECTACULAR SYSTEM.
SYNOPTIC SUPPORT IS WEAK BUT SUFFICIENT. MODELS MAY BE OVERDOING
MOISTURE SLIGHTLY AS THERE IS NEVER REALLY A GREAT FETCH OF
POLEWARD MOISTURE TRANSPORT. MESOSCALE SUPPORT MAY COMPENSATE A
BIT HOWEVER...AS THERE IS SOME MIDDLING FRONTOGENESIS AND NONZERO
BUT WEAK EPV WHICH MAY HELP...AS WELL AS SNOW RATIOS WHICH MAY BE
JUST SLIGHTLY ABOVE CLIMATOLOGY FOR THE AREA.
IN ALL...EXPECT A SNOWFALL OF 1 TO 3 INCHES...WITH PERHAPS AN
ISOLATED POCKET OR TWO APPROACHING 4.
CONSENSUS TEMPS APPEARED GENERALLY IN THE BALLPARK...ALTHOUGH DID
BUMP DOWN SLIGHTLY AGAIN OWING TO RECENT THIN SNOW COVER.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 315 AM EST MON JAN 18 2016
A PROGRESSIVE UPPER FLOW WILL CONTINUE THROUGH THE LONG TERM WITH
A SOMEWHAT OF A SPLIT FLOW OVER THE CENTRAL AND EASTERN U.S. EARLY
ON. HIGH PRESSURE WILL MOVE EAST ACROSS THE GREAT LAKES THURSDAY
WHILE A SYSTEM IN SOUTHERN STREAM TRACKS ACROSS SOUTHERN U.S. THURSDAY
AND TO THE CAROLINAS ON FRIDAY. THIS SYSTEM WILL BRING SIGNIFICANT
PRECIPITATION AND POSSIBLE SNOW ACCUMULATIONS OVER THE OHIO VALLEY THURSDAY
NIGHT AND FRIDAY. HOWEVER THERE IS A LOT OF UNCERTAINTY ON HOW FAR NORTH
THIS PRECIPITATION WILL REACH ACROSS INDIANA. MODELS INDICATE LITTLE
OR NO PRECIPITATION ACROSS THE NORTHWEST HALF...WHILE MUCH HEAVIER
AMOUNTS OCCUR IN THE EAST AND SOUTH. WILL CONTINUE WITH A BLEND AND
GO SLIGHT CHANCE POPS ACROSS NORTHWEST HALF AND CHANCE POPS IN THE
SOUTHEAST THURSDAY NIGHT AND FRIDAY. WILL ALSO CONTINUE LOW CHANCE POPS
EAST FRIDAY EVENING...THEN DRY MOST AREAS UNTIL LATE SUNDAY AS
WEAK HIGH PRESSURE MOVES EAST ACROSS OUR REGION.
THE GFS SPREADS MIXED RAIN AND SNOW INTO OUR AREA LATE SUNDAY...WHILE
THE EURO KEEPS US MOSTLY DRY UNTIL AFTER THE LONG TERM PERIOD.
OVERALL MODEL INITIALIZATION SEEMS REASONABLE ON TEMPERATURES. MADE A FEW
TWEAKS...BUT NO SIGNIFICANT CHANGES. MODELS INDICATE TEMPERATURES WILL
MODERATE A LITTLE BY EARLY NEXT WEEK.
&&
.AVIATION /DISCUSSION FOR THE 180900Z KIND TAF UPDATE/...
ISSUED AT 315 AM EST MON JAN 18 2016
MINOR TWEAKS MADE TO KIND TAF TO BETTER MATCH CURRENT CONDITIONS.
NO OTHER CHANGES ARE NEEDED AT THIS TIME.
PREVIOUS AVIATION DISCUSSION FOLLOWS...
VERY STEEP LOW LEVEL LAPSE RATES UNDER STRONG COLD ADVECTION CONTINUES
TO PRODUCE SOME CLOUD COVER AROUND 025...ALONG WITH SOME FLURRIES. SHORT
TERM MODEL GUIDANCE SUGGESTS THE COLD ADVECTION WILL SLACKEN OFF A BIT
OVER THE NEXT FEW HOURS...SO LINGERING CLOUD COVER NEAR THIS LEVEL WILL
EVENTUALLY DISSIPATE. ANY CEILINGS/VISIBILITY RESTRICTIONS SHOULD BE
BRIEF AND LOCALIZED.
ADDITIONAL CLOUD COVER BASED AROUND 025 MAY DEVELOP TOWARDS MIDDAY ON
MONDAY AS LOW LEVEL LAPSE RATES STEEPEN UP AGAIN.
SURFACE WINDS GENERALLY 270-290 DEGREES AT 9-12 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON EST MONDAY FOR INZ021-028>031-
035>049-051>057-065.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...CP
SHORT TERM...NIELD
LONG TERM...JH
AVIATION...JAS/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1147 PM EST SUN JAN 17 2016
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 342 PM EST SUN JAN 17 2016
COLD ARCTIC HIGH PRESSURE IN THE WAKE OF A FRONT WILL BRING VERY
COLD CONDITIONS TO THE AREA TONIGHT INTO EARLY TUESDAY. THE
COLDEST NIGHT WILL BE TONIGHT WITH WIND CHILLS LIKELY TO APPROACH
15 TO 20 BELOW ACROSS CENTRAL AND NORTHERN PORTIONS OF CENTRAL
INDIANA. DRY WEATHER CAN BE EXPECTED THROUGH TUESDAY UNDER THE
INFLUENCE OF THIS HIGH. A WEAK LOW PRESSURE SYSTEM WILL PUSH
THROUGH THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...WHICH WILL
BRING ANOTHER ROUND OF LIGHT SNOW ACCUMULATIONS TO THE AREA.
ADDITIONAL LIGHT ACCUMULATIONS WILL BE POSSIBLE LATER IN THE WEEK
AS WELL.
&&
.NEAR TERM /OVERNIGHT/...
ISSUED AT 1139 PM EST SUN JAN 17 2016
A BAND OF LIGHT SNOW SHOWERS IS EVIDENT ON RADAR SOUTH OF
INDIANAPOLIS. WHILE SATELLITE PRODUCTS ARE NOT PICKING UP ANY
CLOUD COVER...OBSERVATIONS ARE SHOWING THE DEVELOPMENT OF CLOUDS
AROUND 1500-3000 FT. RADAR WILL BE OVERSHOOTING ANY FLURRIES
AROUND THE OUTER EDGES OF THE FORECAST AREA...AND SEE THIS
CURRENTLY OVER LAWRENCEVILLE WHERE FLURRIES ARE BEING REPORTED
BUT NO ECHOES APPARENT ON RADAR. THIS DEVELOPMENT IS LIKELY DUE TO
STEEP LAPSE RATES ACROSS THE AREA. RAP SHOWS THESE LOW LEVEL LAPSE
RATES REMAINING IN THE 8 TO 9C RANGE ACROSS THE AREA THROUGH
AROUND 7-8Z. THUS HAVE ADDED PARTLY CLOUDY SKIES AND SCATTERED
FLURRIES ACROSS THE ENTIRE AREA FOR THE NEXT FEW HOURS AS
DEVELOPMENT OF CLOUDS AND FLURRIES COULD OCCUR ANYWHERE DURING
THIS TIME. STARTING AROUND 8Z IN THE RAP LAPSE RATES RETURN TO
MORE STABLE LEVELS AND SHOULD SEE AN END TO ANY FLURRIES AND
EXPECT ANY CLOUDS TO CLEAR THEN.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 342 PM EST SUN JAN 17 2016
DRY WEATHER WILL PERSIST THROUGH TUESDAY AFTERNOON AS ARCTIC HIGH
SLIDES ACROSS THE AREA. WEAK LOW PRESSURE SYSTEM WILL SLIDE ACROSS
THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY...AND LIGHT SNOW
ACCUMULATIONS APPEAR A GOOD POSSIBILITY.
ALL MODEL INDICATIONS POINT TO A SOLID BUT UNSPECTACULAR SYSTEM.
SYNOPTIC SUPPORT IS WEAK BUT SUFFICIENT. MODELS MAY BE OVERDOING
MOISTURE SLIGHTLY AS THERE IS NEVER REALLY A GREAT FETCH OF
POLEWARD MOISTURE TRANSPORT. MESOSCALE SUPPORT MAY COMPENSATE A
BIT HOWEVER...AS THERE IS SOME MIDDLING FRONTOGENESIS AND NONZERO
BUT WEAK EPV WHICH MAY HELP...AS WELL AS SNOW RATIOS WHICH MAY BE
JUST SLIGHTLY ABOVE CLIMATOLOGY FOR THE AREA.
IN ALL...EXPECT A SNOWFALL OF 1 TO 3 INCHES...WITH PERHAPS AN
ISOLATED POCKET OR TWO APPROACHING 4.
CONSENSUS TEMPS APPEARED GENERALLY IN THE BALLPARK...ALTHOUGH DID
BUMP DOWN SLIGHTLY AGAIN OWING TO RECENT THIN SNOW COVER.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 234 PM EST SUN JAN 17 2016
APPEARS THIS PATTERN OF EVERY OTHER DAY SNOW CHANCES WILL
CONTINUE THROUGH THE EXTENDED PERIOD AS ANOTHER SYSTEM IS
PROJECTED BY THE ENSEMBLES TO MOVE ACROSS THE AREA THURSDAY NIGHT
INTO EARLY FRIDAY. THIS SYSTEM MAY CONTAIN A LITTLE MORE IN THE
WAY OF MOISTURE AND FORCING LOOKS ESPECIALLY DECENT/GOOD ACROSS
THE OHIO RIVER VALLEY AND SURROUNDING REGION. IT IS POSSIBLE AT
LEAST 1 TO 2 INCHES OF SNOW COULD FALL DURING THIS TIME ACROSS
THE SOUTHEAST COUNTIES...OF COURSE THIS IS VERY EARLY IN THE
FORECAST PROCESS TO BE DISCUSSING EXACT SNOWFALL TOTAL AMOUNTS...BUT
HAVE NOTED THAT THIS SYSTEM MAY PRODUCE MORE THAN A FEW TENTHS OF
AN INCH OF SNOW. IN ADDITION THE FOCUS IS MAINLY FOR
BETTER CHANCES (POPS) SOUTH OF THE INTERSTATE 70 CORRIDOR. THEN
DRY WEATHER WILL PREVAIL FOR THE NEXT TWO DAYS BEFORE THE NEXT
SYSTEM APPROACHES THE AREA EARLY NEXT WEEK.
&&
.AVIATION /DISCUSSION FOR THE 180600Z TAFS/...
ISSUED AT 1133 PM EST SUN JAN 17 2016
VERY STEEP LOW LEVEL LAPSE RATES UNDER STRONG COLD ADVECTION CONTINUES
TO PRODUCE SOME CLOUD COVER AROUND 025...ALONG WITH SOME FLURRIES. SHORT
TERM MODEL GUIDANCE SUGGESTS THE COLD ADVECTION WILL SLACKEN OFF A BIT
OVER THE NEXT FEW HOURS...SO LINGERING CLOUD COVER NEAR THIS LEVEL WILL
EVENTUALLY DISSIPATE. ANY CEILINGS/VISIBILITY RESTRICTIONS SHOULD BE
BRIEF AND LOCALIZED.
ADDITIONAL CLOUD COVER BASED AROUND 025 MAY DEVELOP TOWARDS MIDDAY ON
MONDAY AS LOW LEVEL LAPSE RATES STEEPEN UP AGAIN.
SURFACE WINDS GENERALLY 270-290 DEGREES AT 9-12 KTS THROUGH MIDDAY
MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON EST MONDAY FOR INZ021-028>031-
035>049-051>057-065.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...CP
SHORT TERM...NIELD
LONG TERM...SMF
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
535 PM CST TUE JAN 19 2016
...AVIATION UPDATE...
.SYNOPSIS...
ISSUED AT 243 PM CST TUE JAN 19 2016
A SHRTWV TROF ADVECTING THROUGH NW FLOW LEAD TO SNOW ACROSS THE
IOWA AND N MO THIS AFTERNOON. SNOWFALL TOTALS OF 1 TO 4 INCHES
HAVE BEEN REPORTED IN SW IA INTO S CENTRAL IA. THIS FEATURE WILL
MOVE TO THE EAST THROUGH THE REST OF TODAY. AS THE COLUMN BEGINS
TO SATURATE...SNOW WILL OVERSPREAD THE CWA THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 243 PM CST TUE JAN 19 2016
MAIN FORECAST CONCERN FOR THE SHORT TERM IS THE SNOW THIS
AFTERNOON AND INTO THE EVENING. GUIDANCE AND OBSERVATIONAL TRENDS
SUGGESTS THAT HEAVIEST SNOW...4+ INCHES...WILL OCCUR JUST TO THE
SOUTH OF THE CWA. AS A RESULT...UPDATED SNOW TOTALS AND CURRENT
CHANGES TO THE FORECAST WILL RESULT IN THE ADDITION OF MCDONOUGH
COUNTY IN THE WS.Y. THE BEST CHANCE FOR 3+ INCHES WILL BE SOUTH OF
A LINE FROM MACOMB TO KEOSAUQUA.
HIRES GUIDANCE....SPECIFICALLY THE HRRR AND HIRES NMM KEEPS THE
HEAVIEST SNOW TO OUR SOUTH THIS EVENING. THIS LINES UP WITH AN
OMEGA SIGNAL IN THE DGZ AS WELL. IT APPEARS THAT LIGHT SNOW WILL
OVERSPREAD THE AREA FROM WEST TO EAST. NEAR 00Z...AS THE OMEGA
INCREASES ACROSS THE SOUTH...SNOW INTENSITY SHOULD PICK UP. AT
THIS TIME...THE VORT WILL BE QUICKLY MOVING THROUGH LEADING TO A
QUICK END TO THE SNOW FROM WEST TO EAST. THINK THAT MOST OF THE
SNOW WILL BE OVER AOA 06Z WED. A LOOK AT THE FORECAST PLUMES
SUGGESTS THAT THE HIGHEST CONFIDENCE FOR 3+ INCHES WILL BE ACROSS
OUR EXTREME SOUTH. SNOW TOTALS SHOULD RAPIDLY DECREASE AS YOU
MOVE NORTH OF HWY 34 CORRIDOR WITH THE QC SEEING AROUND AN INCH
TOTAL. THIS IS SUPPORTED BY THE HIRES GUIDANCE AND ENSEMBLE
OUTPUT.
PAST THIS..IT LOOKS LIKE SOME OF THE WARMEST TEMPS IN THE PAST
COUPLE OF DAYS WILL BE TOMORROW WITH NO CHANCE OF POPS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 243 PM CST TUE JAN 19 2016
QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA WEDNESDAY
NIGHT THROUGH THURSDAY AS HIGH PRESSURE QUICKLY MOVES THROUGH THE
AREA. TEMPERATURES WILL AVERAGE BELOW NORMAL.
ON THURSDAY NIGHT...MAINLY DRY CONDITIONS ARE EXPECTED AS THE HIGH
MOVES INTO THE OHIO VALLEY. A WEAK DISTURBANCE MOVING THROUGH THE
UPPER MIDWEST MAY BRING SOME FLURRIES OR VERY LIGHT SNOW TO THE
HIGHWAY 20 CORRIDOR WEST OF DUBUQUE.
DRY CONDITIONS WILL THEN BE SEEN ACROSS THE AREA ON FRIDAY AS
ANOTHER HIGH PRESSURE BUILDS INTO THE MIDWEST. TEMPERATURES WILL BE
SLIGHTLY BELOW NORMAL.
FRIDAY NIGHT ON...
THE MODEL CONSENSUS HAS DRY CONDITIONS FRIDAY NIGHT THROUGH SUNDAY
AS HIGH PRESSURE MOVES INTO THE OHIO VALLEY. TEMPERATURES WILL
SLOWLY CLIMB TO ABOVE NORMAL ON SUNDAY. ATTENTION THEN TURNS TO A
POTENTIAL STORM SYSTEM.
SUNDAY NIGHT INTO MONDAY THE MODELS DIVERGE ON THEIR RESPECTIVE
SOLUTIONS. THE ECMWF IS DRY BUT THE GEM AND TO A MUCH LESSER EXTENT
THE GFS SUGGEST A WEAK STORM SYSTEM MOVING THROUGH THE AREA. GIVEN
THE CONSIDERABLE DIFFERENCES...THE MODEL CONSENSUS HAS SLIGHT CHANCE
POPS FOR SUNDAY NIGHT AND MONDAY.
MONDAY NIGHT AND TUESDAY THE MODEL CONSENSUS HAS DRY CONDITIONS AS
HIGH PRESSURE BUILDS INTO THE MIDWEST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 524 PM CST TUE JAN 19 2016
A LIGHT SNOW EVENT WILL OCCUR THIS EVENING...FROM WEST TO EAST
OVER EASTERN IOWA AND NORTHERN ILLINOIS. THIS WILL BRING
VISIBILITIES DOWN TO IFR...AND CIGS TO MVFR FOR A PERIOD THIS
EVENING...LIKELY BETWEEN 00Z AND 04Z...BEFORE LIFTING BACK TO
HIGHER END MVFR LATE THIS EVENING. SNOW SHOULD ACCUMULATE TO A
SMALL AMOUNT UNDER 2 INCHES AT ALL TAF SITES. WHILE THE CONDITIONS
SHOULD IMPROVE AFTER THE SNOW ENDS...THIS WILL BE TEMPORARY...AS
THE LIGHT MOIST FLOW IS LIKELY TO SEE LOW CLOUDS AND AND LIGHT FOG
DEVELOP AGAIN TOWARD MORNING...WHICH WILL THEN LINGER INTO MID DAY
WEDNESDAY. EXPECT IMPROVEMENT TO HIGH END MVFR TO LOWER VFR BY 18Z
WEDNESDAY. WINDS WILL BE LIGHT SOUTH TO EAST DURING THE PERIOD.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LEE-VAN
BUREN.
IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR HANCOCK-
MCDONOUGH.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK-
SCOTLAND.
&&
$$
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...08
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
432 PM MST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 210 PM MST TUE JAN 19 2016
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS RIDGING ACROSS THE
ROCKIES WITH A SHORTWAVE TROUGH TRANSITIONING OUT OF THE PLAINS
TOWARDS THE CENTRAL MISSISSIPPI RIVER VALLEY. ANOTHER SHORTWAVE
TROUGH UPSTREAM OF THE RIDGE IS MOVING INTO THE PACIFIC NORTHWEST
WITH A MUCH STRONGER WEST-EAST ORIENTATED UPPER LEVEL JET OVER
NORTHERN CALIFORNIA. AT THE SURFACE LEE TROUGH HAS DEVELOPED OVER
EAST CENTRAL COLORADO (NEAR FRONT RANGE) AND WARM FRONT IS IN THE
PROCESS OF LIFTING OVER THE NORTHEAST PART OF OUR CWA (FROM KMCK TO
KHLC). PERSISTENT STRATUS IS STILL IN PLACE IN OUR EASTERN CWA WITH
CLOUD SHIELD BREAKING UP IN THE WEST.
THIS EVENING-WEDNESDAY MORNING...MAIN CONCERN WILL FOCUS ON POSSIBLE
DENSE FOG DEVELOPMENT THIS EVENING/OVERNIGHT. MODELS SUPPORT LEE
TROUGH SHIFTING EASTWARD WITH SOUTHERLY FLOW QUICKLY DEVELOPING
AFTER SUNSET. THIS SHOULD HELP ADVECT GOOD BL MOISTURE BACK INTO OUR
CWA AND STRATUS IN THE EAST COULD THEN EXPAND WESTWARD. EARLIER
HRRR/RAP SUPPORTED FOG REDEVELOPING AFTER 00Z THIS EVENING NEAR THE
CO/KS BORDER AND SPREADING EASTWARD. LATEST SREF/NAM/RAP/HRRR NOW
SHOWING STRONGER SIGNAL AFTER MIDNIGHT TONIGHT THROUGH EARLY
WEDNESDAY MORNING WITH MAIN FOG AXIS SHIFTED FURTHER EAST (TOWARD
BACK EDGE OF CURRENT STRATUS DECK). I KEPT FOG COVERAGE/TIMING
SIMILAR TO EARLY GUIDANCE COVER POSSIBILITY...HOWEVER CONFIDENCE AT
THIS POINT IS SIGNIFICANTLY LOWER ON WHERE OR IF DENSE FOG MAY
DEVELOP OVER OUR CWA. (FOG MAY BE A GOOD BET BUT DENSE FOG MAY BE
PATCHY).
WEDNESDAY...TWO SHORTWAVES ARE EXPECTED TO MOVE ACROSS THE ROCKIES
AND OVER OUR CWA WITH THE FIRST (WEAKER) SHORTWAVE MOVING OVER OUR
CWA MIDDAY WEDNESDAY. AS WAS INDICATED IN EARLIER GUIDANCE ON MID
SHIFT THERE IS A SIGNIFICANT DRY LAYER FROM ABOVE THE BL TO 600-
700MB. DESPITE FORCING THIS LOWERS CONFIDENCE IN ANY MEASURABLE
PRECIP DURING THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON THE
SECOND (STRONGER) SHORTWAVE TROUGH DIGS SOUTHEAST AND OVERTAKES THE
FIRST TROUGH WITH A STRONGER UPPER LEVEL JET BEGINNING TO DEVELOP.
BY LATE AFTERNOON THERE IS A WEAK PRECIP SIGNAL IN OUR FAR EASTERN
CWA AND GUIDANCE THERE DOES SHOW SOME MOISTENING OF THE MOISTURE
PROFILE. I KEPT SMALL AREA OF SLIGHT CHANCE POPS IN GRAHAM/NORTON
COUNTIES TO MATCH THIS...BUT CONFIDENCE IS STILL NOT HIGH THAT
THINGS WOULD START THIS EARLY.
OTHER CONCERN FOR WEDNESDAY WILL BE HIGHS. POTENTIAL EXISTS AGAIN
FOR LINGERING STRATUS...HOWEVER WITH TROUGHS MOVING THROUGH THE
REGION THICK/OPAQUE MID-HIGH CLOUD COVER COULD ALSO LIMIT DIURNAL
HEATING. I LOWERED HIGHS IN THE EAST FROM PREVIOUS FORECAST DUE TO
POTENTIAL IMPACTS OF CLOUD COVER. TOUGH CALL AND IF WE WERE TO
CLEAR OUT (MORE LIKELY IN THE WEST) WE COULD SEE HIGHS IN THE
UPPER 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 248 PM MST TUE JAN 19 2016
FORECAST ISSUES WILL BE CHANCE OF PRECIPITATION AND PHASE OF
PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY. SATELLITE SHOWING A
SOMEWHAT AMPLIFIED BUT STILL PROGRESSIVE AND ACTIVE FLOW PATTERN
FROM THE PACIFIC INTO THE WESTERN ATLANTIC. LARGE AND COMPLICATED
UPPER TROUGH IS OVER THE NORTHEAST PACIFIC.
AT JET LEVEL...THE MODELS WERE HAVING A LITTLE TROUBLE WITH THE JET
ALONG THE WEST COAST. AT MID LEVELS...MODELS WERE ALL ABOUT THE SAME
BUT THEY WERE ALSO A LITTLE FAR EAST/FAST WITH THE UPPER TROUGH NOW
COMING ON THE COAST. THE NAM/ECMWF WAS DOING THE BEST ON THE SURFACE
WIND AND PRESSURE FIELD. THE GFS AND CANADIAN WERE DOING THE BEST ON
THE LOW LEVEL THERMAL FIELD WITH MOST MODELS NOT BEING COLD ENOUGH.
WEDNESDAY NIGHT...DEVELOPING PRECIPITATION EVENT IS IN ITS BEGINNING
STAGES. MODELS DIFFERENT ON SPEED...POSITION AND AMPLITUDE OF MID
LEVEL CIRCULATION THAT APPEARS TO BE DEVELOPING ON TOP OF US OR JUST
TO THE EAST OF US. TODAYS MODEL RUNS VERY DIFFERENT THAN 24 HOURS
AGO. BY THE BEGINNING OF THIS PERIOD...MODELS STILL HAVE STRONG
NORTH TO SOUTH JET ON THE WEST SIDE OF THIS UPPER SYSTEM.
THIS COMBINED WITH THE PROBLEM OF THE MODELS INITIALLY HAVING THIS
SYSTEM TOO FAR EAST THIS MORNING...LEADS ME TO BELIEVE THAT WHATEVER
ENDS UP BEING THE SLOWER AND EVEN FURTHER SOUTH SOLUTION WILL END UP
BEING MORE RIGHT. EVEN NOW AM THINKING CURRENT MODEL RUN STILL MAY
BE TOO FAST/FAR NORTH. TROUGH IS ELONGATED AND COMPROMISED OF A
NORTHERN AND SOUTHERN CIRCULATIONS WITHIN THIS TROUGH. PAST
EXPERIENCE HAS SHOWN THIS SETUP IS NOT GREAT FOR A LOT OF
PRECIPITATION.
SAYING ALL THAT...THE FAR EASTERN PORTION OF THE AREA WILL HAVE THE
BEST CHANCE WITH BEST CHANCE OVERALL AT THIS TIME BEING TO THE EAST
OF OUR AREA. THE GRADIENT OF THE CHANCE OF PRECIPITATION WILL BE
REALLY SHARP. PER THE REASONING ABOVE...AM THINKING THAT THE BEST
CHANCE OF PRECIPITATION WILL BE AFTER MIDNIGHT AND THAT IS SUPPORTED
BY THE SREF PROBABILITIES. BEST CHANCE WILL BE VERY LATE IN THE
NIGHT.
THERE IS NOT A LOT OF COLD AIR WITH THIS SYSTEM...AND DEPENDING ON
WHICH MODEL YOU CHOOSE THE CHANGE OVER MAY NOT OCCUR UNTIL LATE
EVENING/AROUND MIDNIGHT WITH THE EASTERN AREAS CHANGING OVER FIRST.
THE PHASE IS REALLY WHERE THERE ARE BIG DIFFERENCES. SOME MODELS
KEEPING TOTALLY DRY OR HAVE JUST ENOUGH MOISTURE IN THE LOW LEVELS
FOR DRIZZLE/FREEZING DRIZZLE. SO A LOT OF UNCERTAINTY WITH THIS
SYSTEM.
THURSDAY/THURSDAY NIGHT...WITH THE PROXIMITY OF THE SYSTEM AND
EXPECTED SLOWNESS...ALONG WITH MID AND UPPER LEVEL LIFT
EXPECTED...EXPECT THE BEST CHANCE OF PRECIPITATION WILL BE IN THE
MORNING AND THEN RAPIDLY DECREASE AND END. IF CURRENT FORECAST PANS
OUT...THE FAR EASTERN PORTION OF THE AREA GETS 1 TO 2 INCHES.
GRADIENT AND DOWNWARD MOTION BEHIND THE SYSTEM WILL CREATE BREEZY TO
WINDY CONDITIONS. THE STRONGEST WINDS ARE AFTER THE SNOW ENDS...AND
WITH TEMPERATURES JUST ABOVE FREEZING...DO NOT EXPECT ANY BLOWING
SNOW PROBLEMS AT THIS TIME. CURRENT HIGH TEMPERATURE FORECAST LOOKS
TO BE IN GOOD SHAPE AND MADE ONLY MINOR ADJUSTMENTS. HOWEVER...IF
MORE SNOW THAN EXPECT IT WILL BE COLDER. LIGHT WINDS AND LITTLE
CLOUD COVER WILL ALLOW OVERNIGHT TEMPERATURES TO DROP A DECENT
AMOUNT.
FRIDAY...STRONG MID/UPPER LEVEL RIDGE BUILDS IN OVER THE AREA.
SURFACE WILL MOVE THROUGH AND TO THE EAST OF THE AREA DURING THE
DAY. SO DO EXPECT RECYCLED COOL AIR. THE EASTERN LOCATIONS WILL BE
THE COLDEST AND OVERALL REDUCED THE HIGH TEMPERATURES A LITTLE.
FRIDAY NIGHT THROUGH TUESDAY...MID AND UPPER RIDGE WILL BE IN PLACE
FROM FRIDAY NIGHT INTO SATURDAY NIGHT SO EXPECT MODERATING
TEMPERATURES AND DRY CONDITIONS. THE INIT WAS REASONABLE WITH THIS
AND MADE NO CHANGES.
A STRONG SHORTWAVE TROUGH...NOT UNLIKE THE ONE THAT WENT THROUGH
THIS MORNING AND SIMILAR ALSO THE SYSTEM EXPECTED WEDNESDAY NIGHT
AND THURSDAY...WILL MOVE THROUGH SUNDAY AND SUNDAY NIGHT. THE INIT
PRODUCED SLIGHT CHANCE POPS DURING THIS PERIOD AND SEEMS REASONABLE.
POSSIBLE THAT THESE CHANCES WILL INCREASE. AFTER THAT RIDGING WILL
MOVE INTO THE AREA AND BRING DRY CONDITIONS AND MODERATING
TEMPERATURES ONCE AGAIN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 424 PM MST TUE JAN 19 2016
VFR CONDITIONS WILL CONTINUE AT KGLD THIS EVENING AND THEN
LOWER TO MVFR OVERNIGHT. CONFIDENCE IN JUST HOW LOW CONDITIONS
COULD DROP AT KGLD IS LOW. THE PREVIOUS FORECAST WAS PESSIMISTIC
BUT THE LATEST HRRR DOES NOT FAVOR FOG DEVELOPMENT AT KGLD. IF
CONDITIONS LOWER OVERNIGHT, THEY SHOULD IMPROVE TO VFR BY MID
MORNING AND CONTINUE THROUGH THE AFTERNOON.
THE LATEST SATELLITE AT KMCK INDICATES CONDITIONS AT KMCK SHOULD
IMPROVE TO VFR SHORTLY. MODELS BRING CONDITIONS BACK DOWN TO MVFR
BY 04Z AND THIS SEEMS REASONABLE BASED ON FAVORABLE BOUNDARY LAYER
RH. CONDITIONS SHOULD IMPROVE BY LATE MORNING WITH VFR FOR THE
REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
AREA FORECAST DISCUSSION
NWS WICHITA KS
1133 PM CST SUN JAN 17 2016
...UPDATED FOR 06Z AVIATION DISCUSSION...
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM CST SUN JAN 17 2016
ELONGATED BAND OF -SHSN PERSISTING ACROSS FORECAST AREA LATE THIS
AFTERNOON...DUE TO PERSISTENT...MOIST...ISENTROPIC UPGLIDE 285-290K
THETA SURFACES...ENHANCED BY WEAK JET STREAK APPARENT IN WATER VAPOR
IMAGERY. 06UTC NAM PROVIDED SOME HINT...AND 17UTC RAP APPEARS TO BE
BEST PREDICTIVE VALUE AT PRESENT. EXPECT POTENTIAL FOR SNOW SHOWERS
TO DIMINISH BY EARLY TO MID-EVENING.
AFTER SNOW CHANCES DIMINISH...MAY FORECAST CONCERN WILL BE OVERNIGHT
TEMPERATURES. CLOUD COVER WILL PERSIST MOST OF THE NIGHT...WHICH
WILL HELP COUNTER RADIATIVE AND ADVECTION COOLING. DUE TO SNOW PACK
ACROSS NORTHEAST KANSAS...TRENDED SLIGHTLY COLDER THAN GUIDANCE
FLINT HILLS INTO NORTH CENTRAL KANSAS DUE TO ADVECTIVE PROCESSES.
TEMPERATURES WILL BE ABLE TO REBOUND ABOVE FREEZING CENTRAL AND
SOUTH CENTRAL KANSAS ON MONDAY...DUE TO RETURN SOUTHERLY FLOW.
SOUTHEAST AND NORTHEAST KANSAS WILL REMAIN UNDER GRIP OF
DEEPER...COLDER AIRMASS...THUS MAX TEMPS ONLY EXPECTED TO REACH MID
TO UPPER 20S. TEMPERATURES MONDAY INTO TUESDAY WILL MODERATE DUE TO
SOUTHERLY FLOW...BUT THEN ANOTHER FAST MOVING SYSTEM WILL DIVE
ACROSS THE PLAINS BRINGING ANOTHER SHOT OF COLDER AIR AND POSSIBLY A
CHANCE OF LIGHT SNOW OR RAIN/SNOW MIX TUESDAY AFTERNOON AND TUESDAY
NIGHT.
ANOTHER FAST MOVING SHORT WAVE DIVES INTO SOUTHERN PLAINS WEDNESDAY
NIGHT INTO TUESDAY. FORECAST MODELS DEEPENED/INTENSIFIED THIS OPEN
WAVE THE PAST FEW RUNS. DETERMINISTIC MODELS ARE SHOWING
VARIABILITY IN TRACK AND DEPTH OF H5/SURFACE LOW...WHICH WILL HAVE
IMPACT ON PRECIPITATION TYPE. GFS IS MORE BULLISH WITH PRECIPITATION
AND EVOLVES WARM AND MOIST CONVEYOR BELT MORE SO THAN ECWMF. GFS
ENSEMBLES ALL OVER THE PLACE WITH H5 EVOLUTION AND EC MEAN ENSEMBLE
LOOKS RATHER ANEMIC. GIVEN UNCERTAINTY...KEPT PRECIPITATION CHANCES
ON THE LOW SIDE AND DID NOT GET TOO SPECIFIC WITH PRECIPITATION
TYPE.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 335 PM CST SUN JAN 17 2016
EXTENDED PART OF THE FORECAST PERIOD INDICATES A WARMING AND DRY
TREND AS H5 RIDGING BUILDS OVER INTERMOUNTAIN WEST FRIDAY AND
SATURDAY.
SF
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1131 PM CST SUN JAN 17 2016
VFR CONDITIONS FORECAST AT ALL SITES THROUGHOUT THE PERIOD. SURFACE
RIDGE AXIS CONTINUES TO MOVE ACROSS THE AREA WITH LIGHT VARIABLE
WINDS AT MOST LOCATIONS AT ONSET. WEAK RETURN FLOW DEVELOPS ON
MON. FOG/STRATUS ALONG WESTERN CORRIDOR IN RETURN OF LOW LEVEL
MOISTURE SEEMS UNLIKELY AT THIS POINT...BUT MAY BE A PROBLEM LATE MON
NIGHT. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 9 31 23 38 / 20 0 0 30
HUTCHINSON 8 32 24 34 / 20 0 0 30
NEWTON 6 30 22 34 / 20 0 0 30
ELDORADO 7 29 22 37 / 20 0 0 40
WINFIELD-KWLD 9 31 23 42 / 20 0 0 30
RUSSELL 8 35 23 32 / 10 0 10 30
GREAT BEND 8 36 24 33 / 10 0 10 20
SALINA 6 31 21 31 / 20 0 10 30
MCPHERSON 8 31 23 33 / 20 0 10 30
COFFEYVILLE 10 29 23 45 / 40 10 0 40
CHANUTE 6 27 20 41 / 30 0 10 40
IOLA 5 26 20 40 / 30 0 0 50
PARSONS-KPPF 6 28 21 43 / 40 0 0 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1048 PM EST TUE JAN 19 2016
.UPDATE...
ISSUED AT 1040 PM EST TUE JAN 19 2016
THE LEADING EDGE OF PRECIPITATION FROM A SYSTEM TO AFFECT THE
REGION LATER TONIGHT AND INTO WEDNESDAY NIGHT HAS MOVED INTO
SOUTHERN IL AND FAR WESTERN KY. THIS PRECIPITATION SHOULD CONTINUE
TO SPREAD EAST OVERNIGHT AND INTO WEDNESDAY MORNING.
THE 18Z NAM AND NOW THE 0Z NAM HAVE POINTED TOWARD HIGHER QPF IN
THE FAR SW COMPARED TO THE PREVIOUS FORECAST. THE 0Z GFS ALSO HAS
QPF THAT SHOULD BE ENTIRELY OR ALMOST ENTIRELY SNOW OF AROUND 0.40
INCHES IN WAYNE COUNTY. WITH SNOW RATIOS EXPECTED TO BE 10 TO 11
TO 1 THAT WOULD PROBABLY PUSH WAYNE COUNTY TO AT OR SLIGHTLY ABOVE
THE 12 HOUR WINTER STORM WARNING CRITERIA OF 4 INCHES. WITH THIS
IN MIND...WAYNE COUNTY HAS BEEN UPGRADED TO A WINTER STORM
WARNING FOR 3 TO 5 INCHES OF SNOW. NEIGHBORING COUNTIES TO WANE
SHOULD PICK UP AMOUNTS IN THE 2 TO 4 INCH RANGE...WITH AMOUNTS
TAPERING OFF FROM THERE TO THE NORTH AND EAST DUE TO DRIER AIR IN
PLACE. SOME OF THE RECENT RAP AND HRRR RUNS SUPPORT THE 0Z NAM AND
0Z GFS TO AN EXTENT ALTHOUGH THE 2Z RAP HAS HIGHER QPF FURTHER
NORTH INTO THE PULASKI TO LAUREL COUNTY CORRIDOR. THE MOST RECENT
HRRR IS SLIGHTLY LIGHTER WITH AM SNOW IN THE SW COUNTIES COMPARED
TO A COUPLE OF EARLIER RUNS...SO OVERALL SOME UNCERTAINTY REMAINS
EVEN WITH THIS SYSTEM. HOWEVER...THERE SEEMS TO BE AN UPWARD TREND
IN QPF AND SNOWFALL FOR THE FAR SW THUS THE WAYNE COUNTY UPGRADE.
AN UPDATED WSW AND HWO HAVE BEEN ISSUED.
AS FOR THE LATE WEEK SYSTEM...THE DISTURBANCES THAT SHOULD INTERACT
OR PHASE TOGETHER FOR THE EASTERN CONUS TROUGH AND LOW PRESSURE
SYSTEM ARE NOW ONSHORE OF THE WESTERN U.S. OR MOVING ONSHORE AT
THIS TIME. AS UPPER AIR NETWORKS BEGIN TO CAPTURE THE STRENGTH OF
THESE SYSTEMS...MODEL RUNS FROM 0Z THIS MORNING AND INTO WEDNESDAY
SHOULD BEGIN TO CLOSE IN WITH MORE OF A CONSENSUS. THIS SYSTEM
WILL CONTINUE TO BE MONITORED AND IS ALSO BEING HIGHLIGHTED IN
WEATHERSTORIES AND HWO.
UPDATE ISSUED AT 810 PM EST TUE JAN 19 2016
OTHER THAN FINE TUNING THE HOURLY TEMPERATURE FORECAST FOR THE
NEXT FEW HOURS...NO CHANGES ARE NEEDED AT THIS TIME. AS THE 0Z
MODEL RUNS COME IN AS WELL AS THE 21Z SREF AND HRRR AND RAP RUNS
WILL BE EVALUATED FOR WHETHER OR NOT QPF AND SNOW AMOUNTS MAY NEED
TO INCREASED ACROSS THE LAKE CUMBERLAND REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 406 PM EST TUE JAN 19 2016
CURRENT CONDITIONS ACROSS THE AREA FEATURE CLOUD COVER ON THE
INCREASE IN WESTERN KENTUCKY ASSOCIATED WITH A DEVELOPING SYSTEM.
MEANWHILE...IN EASTERN KENTUCKY CLOUD COVER IS DISSIPATING AS
NORTHWEST UPSLOPE FLOW DECREASES AS THE CENTER OF THE ARCTIC HIGH
HAS MOVED OVER THE AREA. THUS HAVE CLEARED SKY COVER AND SHUT OFF
THE FLURRIES ACROSS THE AREA AS WELL. AFTER 00Z TONIGHT...SKIES
WILL CLOUD UP AGAIN AS THE NEXT SYSTEM MOVES THROUGH THE
BLUEGRASS. PRECIP WILL BEGIN TO MOVE INTO THE AREA AFTER 08Z.
MODEL TRENDS HAVE KEPT THIS FEATURE WITH A GOOD AMOUNT OF LIFT AND
MOISTURE. TRENDS HAVE ALSO TAKEN THE MOST AMOUNT OF MOISTURE TO
THE SOUTH INTO CENTRAL KY AND THEN INTO TN JUST CLIPPING WETS OF
THE I-75 CORRIDOR. THIS REGION WILL LIKELY SEE THE MOST AMOUNT OF
SNOW FROM THIS FEATURE. SURFACE TEMPS AS THIS FEATURE MOVES IN
WILL JUST BE RECOVERING FROM THE ARCTIC AIR MASS THAT HAS JUST
EVACUATED THE AREA. THUS PRECIP WILL BEGIN AS SNOW FOR THIS
SYSTEM. WARMEST TEMPS THOUGH WILL BE IN THE SOUTH WITH SOUTHERLY
FLOW SETTING UP AHEAD OF THE FRONT. THUS...SNOW RATIOS WILL BE
SLIGHTLY LOWER THAN THE NORTH AS THIS FEATURE MOVES INTO THE AREA.
SNOW WILL CONTINUE ACROSS EASTERN KENTUCKY THROUGH THE DAY AND
BECOME MODERATE TO EVEN HEAVY AT TIMES. HIGH RATIOS TO THE NORTH
WILL MAKE FOR SNOWFALL AMOUNTS IN THE 1 TO 2 INCH RANGE BUT MORE
MOISTURE IN THE SOUTH WILL MAKE FOR 2 TO 3+ AMOUNTS DESPITE THE
LOWER SNOW RATIOS.
THE OTHER CONCERN FOR SNOW AMOUNTS WITH THIS FEATURE WILL BE THE
PROGRESSIVE FLOW AS THIS SYSTEM MOVES THROUGH. AS THE SYSTEM LOSES
A BIT OF MOISTURE MOVING INTO THE AREA...THE DEPTH OF THE MOISTURE
LESSENS QUITE QUICKLY BY WEDNESDAY AFTERNOON AND INTO WEDNESDAY
NIGHT. DUE TO THIS MUCH OF THE SNOW WILL CHANGE OVER TO FREEZING
DRIZZLE HEADING INTO WEDNESDAY EVENING AND WEDNESDAY NIGHT. IN
FACT...A GLAZE OF ICE IS POSSIBLE IN SOME AREAS...ESPECIALLY IN
THE SOUTH...WHERE UP TO 0.05 HUNDREDTHS ARE POSSIBLE. THIS SET UP
MAY ALSO TAKE AWAY FROM SOME OF THE SNOWFALL POTENTIAL IN THE
SOUTH. THUS...WILL KEEP THE WINTER WEATHER ADVISORY OUT FOR THE
ENTIRE AREA FROM TOMORROW MORNING AND THROUGH THURSDAY NIGHT.
HEADING INTO WEDNESDAY NIGHT...THE SYSTEM EXITS THE AREA AS THE
LAST OF THE LOW LEVEL MOISTURE EXITS AS WELL. THIS WILL BRING AN
END TO THE FREEZING DRIZZLE THREAT BEFORE THE NEXT FEATURE BEGINS
TO IMPACT THE AREA MOVING IN FROM THE SOUTH. IN FACT...WE WILL
HAVE A BRIEF BREAK IN THE PRECIP BY THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 406 PM EST TUE JAN 19 2016
COMPLICATED FORECAST IN THE LONG TERM WITH LOTS OF ATTENTION ON A
POSSIBLE MAJOR WINTER STORM IN THE THURSDAY NIGHT THROUGH SATURDAY
TIME RANGE.
AS OUR MIDWEEK WINTER SYSTEM PASSES TO OUR EAST...TEMPERATURES
ALOFT WILL BE ON THE RISE AS A WARM FRONT AT THE SURFACE MOVES UP
THE GREAT VALLEY OF EAST TENNESSEE VALLEY. THIS WILL SEND
PRECIPITATION BACK NORTH INTO THE AREA LATE THURSDAY INTO THURSDAY
NIGHT. THERMAL PROFILE IS TRICKY BUT P-TYPE IS EXPECTED TO BE
MOSTLY RAIN ACROSS THE SOUTH BUT A MIX OF RAIN...SNOW AND FREEZING
RAIN ALONG AND NORTH OF THE HAL ROGERS PARKWAY THURSDAY
NIGHT...AND PROBABLY ALL SNOW OR A MIX OF FREEZING RAIN AND SNOW
FROM I-64 NORTH. FORECAST MODELS THEN DIVERGE INTO FRIDAY BUT THE
PRESENCE OF AN INVERTED TROUGH EXTENDING UP THE GREAT VALLEY OF
EAST TENNESSEE INTO THE CUMBERLAND VALLEY WOULD SUPPORT A SCENARIO
WHERE THE WARM NOSE ALOFT EDGES FURTHER NORTH CAUSING PRECIP TO
MIX WITH OR CHANGE TO RAIN PERHAPS AS FAR NORTH AS THE MOUNTAIN
PARKWAY AND POSSIBLY EVEN I-64. THE NORTHWARD EXTEND TO THE CHANGE
TO RAIN DEPENDS GREATLY ON THE STRENGTH AND TRACK OF THE SURFACE
LOW...WITH WHICH THERE IS JUST A LOT OF UNCERTAINTY DUE TO MODEL
DIFFERENCES SO TRIED TO PAINT WITH A BROAD BRUSH AS FAR AS THE
ACTUAL P-TYPE FORECAST GOES RIGHT NOW THROUGH THE DAY FRIDAY.
SO...WHILE THE ACTUAL WEATHER YOU WILL SEE REMAINS UNCERTAIN
THURSDAY NIGHT AND FRIDAY...PLAN TO BE IMPACTED BY THE WEATHER IN
SOME FORM OR FASHION IF YOU HAVE TRAVEL PLANS AND MONITOR
FORECASTS AS OUR CONFIDENCE IN THE DETAILS IMPROVES OVER THE NEXT
DAY OR SO.
MODELS ARE FAIRLY CONSISTENT THAT COLDER AIR WILL WRAP IN BEHIND
THE DEPARTING SURFACE LOW FRIDAY EVENING CHANGING ALL PRECIP TO
SNOW QUICKLY FROM NORTHWEST TO SOUTHEAST. THE SNOW WILL LIKELY
CONTINUE THROUGH AT LEAST SATURDAY MORNING...AND POSSIBLY EVEN
INTO SATURDAY NIGHT AS THE UPPER LOW IS SLOW TO PIVOT THROUGH. THE
POTENTIAL EXISTS FOR SEVERAL INCHES OF SNOW.
THE REMAINDER OF THE EXTENDED WILL FEATURE WARMING TEMPS...
ALTHOUGH POTENTIAL SNOW COVER WILL HAVE A YET TO BE DETERMINED
INFLUENCE THERE. ANOTHER SYSTEM IS PROGGED TO DEVELOP OVER THE
SOUTHERN PLAINS AND THEN MOVE NORTHEAST SPREADING ANOTHER CHANCE
FOR PRECIPITATION ACROSS THE AREA AS EARLY AS MONDAY. THIS SHOULD
BE RAIN AS IT APPEARS RIGHT NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 735 PM EST TUE JAN 19 2016
VFR WILL CONTINUE FOR ABOUT THE FIRST 6 HOURS TONIGHT. LATER
TONIGHT...A COLD FRONT WILL BRING SNOWFALL TO THE FAR SOUTHWEST BY
09Z...SPREADING ACROSS THE ENTIRE AREA BY 16Z. THIS WILL THEN
RESULT IN DETERIORATION INTO MVFR AND THEN IFR AND POSSIBLY NEAR
OR BELOW AIRPORT MINS AT TIMES FOR VIS IN THE FALLING SNOW AND
AND CIGS DURING SNOW AND AFTER IT DEPARTS AND TAPERS TO DRIZZLE OR
FREEZING DRIZZLE. WINDS WILL BE LIGHT TO NEAR CALM THROUGH THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR KYZ052-060-088-104-106>110-112-113-115-117>120.
WINTER WEATHER ADVISORY FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR KYZ044-050-051-058-059-068-069-079-080-084>087-111-114-116.
WINTER STORM WARNING FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR KYZ083.
&&
$$
UPDATE...JP
SHORT TERM...SHALLENBERGER
LONG TERM...ABE
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
817 PM EST TUE JAN 19 2016
.UPDATE...
ISSUED AT 810 PM EST TUE JAN 19 2016
OTHER THAN FINE TUNING THE HOURLY TEMPERATURE FORECAST FOR THE
NEXT FEW HOURS...NO CHANGES ARE NEEDED AT THIS TIME. AS THE 0Z
MODEL RUNS COME IN AS WELL AS THE 21Z SREF AND HRRR AND RAP RUNS
WILL BE EVALUATED FOR WHETHER OR NOT QPF AND SNOW AMOUNTS MAY NEED
TO INCREASED ACROSS THE LAKE CUMBERLAND REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 406 PM EST TUE JAN 19 2016
CURRENT CONDITIONS ACROSS THE AREA FEATURE CLOUD COVER ON THE
INCREASE IN WESTERN KENTUCKY ASSOCIATED WITH A DEVELOPING SYSTEM.
MEANWHILE...IN EASTERN KENTUCKY CLOUD COVER IS DISSIPATING AS
NORTHWEST UPSLOPE FLOW DECREASES AS THE CENTER OF THE ARCTIC HIGH
HAS MOVED OVER THE AREA. THUS HAVE CLEARED SKY COVER AND SHUT OFF
THE FLURRIES ACROSS THE AREA AS WELL. AFTER 00Z TONIGHT...SKIES
WILL CLOUD UP AGAIN AS THE NEXT SYSTEM MOVES THROUGH THE
BLUEGRASS. PRECIP WILL BEGIN TO MOVE INTO THE AREA AFTER 08Z.
MODEL TRENDS HAVE KEPT THIS FEATURE WITH A GOOD AMOUNT OF LIFT AND
MOISTURE. TRENDS HAVE ALSO TAKEN THE MOST AMOUNT OF MOISTURE TO
THE SOUTH INTO CENTRAL KY AND THEN INTO TN JUST CLIPPING WETS OF
THE I-75 CORRIDOR. THIS REGION WILL LIKELY SEE THE MOST AMOUNT OF
SNOW FROM THIS FEATURE. SURFACE TEMPS AS THIS FEATURE MOVES IN
WILL JUST BE RECOVERING FROM THE ARCTIC AIR MASS THAT HAS JUST
EVACUATED THE AREA. THUS PRECIP WILL BEGIN AS SNOW FOR THIS
SYSTEM. WARMEST TEMPS THOUGH WILL BE IN THE SOUTH WITH SOUTHERLY
FLOW SETTING UP AHEAD OF THE FRONT. THUS...SNOW RATIOS WILL BE
SLIGHTLY LOWER THAN THE NORTH AS THIS FEATURE MOVES INTO THE AREA.
SNOW WILL CONTINUE ACROSS EASTERN KENTUCKY THROUGH THE DAY AND
BECOME MODERATE TO EVEN HEAVY AT TIMES. HIGH RATIOS TO THE NORTH
WILL MAKE FOR SNOWFALL AMOUNTS IN THE 1 TO 2 INCH RANGE BUT MORE
MOISTURE IN THE SOUTH WILL MAKE FOR 2 TO 3+ AMOUNTS DESPITE THE
LOWER SNOW RATIOS.
THE OTHER CONCERN FOR SNOW AMOUNTS WITH THIS FEATURE WILL BE THE
PROGRESSIVE FLOW AS THIS SYSTEM MOVES THROUGH. AS THE SYSTEM LOSES
A BIT OF MOISTURE MOVING INTO THE AREA...THE DEPTH OF THE MOISTURE
LESSENS QUITE QUICKLY BY WEDNESDAY AFTERNOON AND INTO WEDNESDAY
NIGHT. DUE TO THIS MUCH OF THE SNOW WILL CHANGE OVER TO FREEZING
DRIZZLE HEADING INTO WEDNESDAY EVENING AND WEDNESDAY NIGHT. IN
FACT...A GLAZE OF ICE IS POSSIBLE IN SOME AREAS...ESPECIALLY IN
THE SOUTH...WHERE UP TO 0.05 HUNDREDTHS ARE POSSIBLE. THIS SET UP
MAY ALSO TAKE AWAY FROM SOME OF THE SNOWFALL POTENTIAL IN THE
SOUTH. THUS...WILL KEEP THE WINTER WEATHER ADVISORY OUT FOR THE
ENTIRE AREA FROM TOMORROW MORNING AND THROUGH THURSDAY NIGHT.
HEADING INTO WEDNESDAY NIGHT...THE SYSTEM EXITS THE AREA AS THE
LAST OF THE LOW LEVEL MOISTURE EXITS AS WELL. THIS WILL BRING AN
END TO THE FREEZING DRIZZLE THREAT BEFORE THE NEXT FEATURE BEGINS
TO IMPACT THE AREA MOVING IN FROM THE SOUTH. IN FACT...WE WILL
HAVE A BRIEF BREAK IN THE PRECIP BY THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 406 PM EST TUE JAN 19 2016
COMPLICATED FORECAST IN THE LONG TERM WITH LOTS OF ATTENTION ON A
POSSIBLE MAJOR WINTER STORM IN THE THURSDAY NIGHT THROUGH SATURDAY
TIME RANGE.
AS OUR MIDWEEK WINTER SYSTEM PASSES TO OUR EAST...TEMPERATURES
ALOFT WILL BE ON THE RISE AS A WARM FRONT AT THE SURFACE MOVES UP
THE GREAT VALLEY OF EAST TENNESSEE VALLEY. THIS WILL SEND
PRECIPITATION BACK NORTH INTO THE AREA LATE THURSDAY INTO THURSDAY
NIGHT. THERMAL PROFILE IS TRICKY BUT P-TYPE IS EXPECTED TO BE
MOSTLY RAIN ACROSS THE SOUTH BUT A MIX OF RAIN...SNOW AND FREEZING
RAIN ALONG AND NORTH OF THE HAL ROGERS PARKWAY THURSDAY
NIGHT...AND PROBABLY ALL SNOW OR A MIX OF FREEZING RAIN AND SNOW
FROM I-64 NORTH. FORECAST MODELS THEN DIVERGE INTO FRIDAY BUT THE
PRESENCE OF AN INVERTED TROUGH EXTENDING UP THE GREAT VALLEY OF
EAST TENNESSEE INTO THE CUMBERLAND VALLEY WOULD SUPPORT A SCENARIO
WHERE THE WARM NOSE ALOFT EDGES FURTHER NORTH CAUSING PRECIP TO
MIX WITH OR CHANGE TO RAIN PERHAPS AS FAR NORTH AS THE MOUNTAIN
PARKWAY AND POSSIBLY EVEN I-64. THE NORTHWARD EXTEND TO THE CHANGE
TO RAIN DEPENDS GREATLY ON THE STRENGTH AND TRACK OF THE SURFACE
LOW...WITH WHICH THERE IS JUST A LOT OF UNCERTAINTY DUE TO MODEL
DIFFERENCES SO TRIED TO PAINT WITH A BROAD BRUSH AS FAR AS THE
ACTUAL P-TYPE FORECAST GOES RIGHT NOW THROUGH THE DAY FRIDAY.
SO...WHILE THE ACTUAL WEATHER YOU WILL SEE REMAINS UNCERTAIN
THURSDAY NIGHT AND FRIDAY...PLAN TO BE IMPACTED BY THE WEATHER IN
SOME FORM OR FASHION IF YOU HAVE TRAVEL PLANS AND MONITOR
FORECASTS AS OUR CONFIDENCE IN THE DETAILS IMPROVES OVER THE NEXT
DAY OR SO.
MODELS ARE FAIRLY CONSISTENT THAT COLDER AIR WILL WRAP IN BEHIND
THE DEPARTING SURFACE LOW FRIDAY EVENING CHANGING ALL PRECIP TO
SNOW QUICKLY FROM NORTHWEST TO SOUTHEAST. THE SNOW WILL LIKELY
CONTINUE THROUGH AT LEAST SATURDAY MORNING...AND POSSIBLY EVEN
INTO SATURDAY NIGHT AS THE UPPER LOW IS SLOW TO PIVOT THROUGH. THE
POTENTIAL EXISTS FOR SEVERAL INCHES OF SNOW.
THE REMAINDER OF THE EXTENDED WILL FEATURE WARMING TEMPS...
ALTHOUGH POTENTIAL SNOW COVER WILL HAVE A YET TO BE DETERMINED
INFLUENCE THERE. ANOTHER SYSTEM IS PROGGED TO DEVELOP OVER THE
SOUTHERN PLAINS AND THEN MOVE NORTHEAST SPREADING ANOTHER CHANCE
FOR PRECIPITATION ACROSS THE AREA AS EARLY AS MONDAY. THIS SHOULD
BE RAIN AS IT APPEARS RIGHT NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 735 PM EST TUE JAN 19 2016
VFR WILL CONTINUE FOR ABOUT THE FIRST 6 HOURS TONIGHT. LATER
TONIGHT...A COLD FRONT WILL BRING SNOWFALL TO THE FAR SOUTHWEST BY
09Z...SPREADING ACROSS THE ENTIRE AREA BY 16Z. THIS WILL THEN
RESULT IN DETERIORATION INTO MVFR AND THEN IFR AND POSSIBLY NEAR
OR BELOW AIRPORT MINS AT TIMES FOR VIS IN THE FALLING SNOW AND
AND CIGS DURING SNOW AND AFTER IT DEPARTS AND TAPERS TO DRIZZLE OR
FREEZING DRIZZLE. WINDS WILL BE LIGHT TO NEAR CALM THROUGH THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR KYZ052-060-088-104-106>110-112-113-115-117>120.
WINTER WEATHER ADVISORY FROM 4 AM WEDNESDAY TO 7 AM EST THURSDAY
FOR KYZ044-050-051-058-059-068-069-079-080-083>087-111-114-116.
&&
$$
UPDATE...JP
SHORT TERM...SHALLENBERGER
LONG TERM...ABE
AVIATION...JP
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
642 PM CST TUE JAN 19 2016
.UPDATE...
Issued at 642 PM CST TUE JAN 19 2016
Watching very closely the precipitation across SEMO, where light
freezing rain/drizzle has been reported and has caused very
dangerous travel conditions. Issued a SPS, and highlighted it more
strongly in the social media realm. May take a look at the WSW.
Thing is, as the upper system moves closer and precip increases,
precip loading, top down cooling will start to erode the "warm"
layer, or at least suppress it toward the MO/AR border, and
transition precip to mainly sleet and snow early this evening. So
for now, will handle this as a very short term event, and not
complicate the overall message. Will make some minor changes to
the grid forecast in this area. The RAP thermal depictions support
this approach.
CN
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 131 PM CST TUE JAN 19 2016
With 12z model suite painting low end 4 tenths qpf, and high end
6 tenths, and ratios low end 12 to 1, and high end 17 to 1, per
collab with WPC and adjacent WFO`s...have upgraded to warn all
areas for broad 3 to 5 inch expectation.
More specifically, some heavier snow could paint a swath of
locally higher amounts (depending upon the solution)... and
higher liquid to snow ratios in cold low to mid 20s air... could
potentially yield a 6+ inch swath. The main threat area for this
is roughly latitudinally along the Ohio river thru the heart of
the FA and southward toward the AR/TN borders.
On the flip side, if more scant amounts of qpf across our north
occur (visa vi the GFS), and using a less gracious LSR, we could
see lesser 2 to 2.5" totals along the I-64 corridor from Mount
Vernon IL into southwest IN.
In summary, broad 3 to 5 inch totals expected snow/sleet. Some
chance slightly lower 2 inch totals possible north, and higher 6+
inch totals a possibility across south-central ptns. Cant rule out
some hundredths of freezing rain across mainly srn border
counties, but focusing mostly on snow/sleet potential given
consistency of colder/further southern/eastern track.
Factors at play for a little more sleet vs snow include 3 to 6K
foot depth of warm nose ranging from -1C to +2C for at times 3 to
6 hrs of pcpn time period. This skews totals a little toward lower
end of aforementioned ratios, if it plays out.
Adjusted start time of WSW to 00z, given accumulating snows could
be ongoing at 03z for farthest western portions of SEMO/SWIL. End
time maintained at 18Z, but effectively ends at 15Z for all but
farthest southeastern counties...as pcpn shuts off sharply
northwest to southeast thru the morning hours Wednesday.
.LONG TERM...(Thursday through Tuesday)
Issued at 255 PM CST TUE JAN 19 2016
Another messy round of winter weather will follow our mid week
event. Models are in good agreement showing a low pressure system
centered over central Mississippi at 00z Friday. Being on the cold
side of the low along with the expected snow pack across our
region, a majority of the precipitation Thursday into Friday will
be freezing or frozen. Precipitation is expected to start as a mix
of freezing rain, sleet and snow across all but our north and
northwest counties, where precipitation should begin as snow and
remain snow through the event. Models imply temperatures briefly
reaching 33 to 37 degrees across most areas by Thursday afternoon,
which would switch us to rain. However confidence is a bit low on
how much warming we can get, so kept most areas as a mix except
for a portion of west Kentucky and southeast Missouri.
For Thursday night, any areas that begin as a mix will switch to
all snow by midnight as the low moves off to our southeast
overnight. The snow will continue into Friday, tapering off from
west to east Friday afternoon into Friday night. Right now 1 to 3
inches of snow is possible, but amounts are questionable at this
point and will greatly depend on how warm our surface temperatures
can get.
The weekend will be dry as high pressures moves across the Gulf of
Mexico. Temperatures will reach the middle 30s Saturday, and
around 40 degrees Sunday. Another round of precipitation will
return for Monday. Models take a surface low right over the PAH
forecast area late Monday into Monday night. Rain is possible
Monday, then as the low moves overhead and east of us, rain will
mix with and change over to snow Monday night. Rain or snow will
then be possible for Tuesday into Tuesday night, but we will have
to continue to watch the track of the low to see just how warm or
cold we will be for the beginning of the work week.
&&
.AVIATION...
Issued at 537 PM CST TUE JAN 19 2016
Downward progression of ceilings and visibilities from VFR to MVFR
and IFR will take place through 06z for all WFO PAH TAF sites with
the oncoming snow. A very brief, less than an hour period of light sleet
(PL) and freezing rain (ZR) at the onset at KCGI and KPAH, but the
duration and likelihood of these precipitation types should lessen
markedly as the night goes on. Although the moist layer will be
very shallow by noon Wednesday, kept an broken/overcast layer in
place through the afternoon.
&&
.PAH Watches/Warnings/Advisories...
IL...Winter Storm Warning until noon CST Wednesday for ILZ075>078-
080>094.
MO...Winter Storm Warning until noon CST Wednesday for MOZ076-086-087-
100-107>112-114.
IN...Winter Storm Warning until noon CST Wednesday for INZ081-082-
085>088.
KY...Winter Storm Warning until noon CST Wednesday for KYZ001>022.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
959 PM CST TUE JAN 19 2016
.DISCUSSION...
A LINE OF BROKEN CONVECTION HAS DEVELOPED OVER THE LAST COUPLE OF
HRS JUST AHEAD OF A COLD FRONT THAT IS ENTERING THE NWRN ZONES.
00Z KSHV RAOB SHOWS A PRONOUNCED DRY LAYER BETWEEN 850-560
MB...INDICATIVE OF SHOW MID LVL DRY SLOTTING IN THE WAKE OF A
DEPARTING SHORTWAVE TROUGH PER LATEST WV LOOPS. SOME ADDITIONAL
MID/UPPER LVL MOISTURE MOVING INTO THE SRN PLAINS COULD HELP THE
ATMOSPHERE MOISTEN FROM THE TOP DOWN IF IT ARRIVES BEFORE THE
FRONT. OTHERWISE...PRECIP WILL REMAIN SPOTTY AND SCATTERED AT
BEST. RAIN CHANCES MIGHT BE A BIT HIGHER ACROSS SRN AR DURING THE
EARLY MORNING HRS AS VERTICAL ASCENT MIGHT BE SLIGHTLY HIGHER DUE
TO THE PROXIMITY OF A SFC LOW AND THE UPPER TROUGH AXIS.
QUITE A FEW CHANGES WERE MADE IN THE GRIDS DURING THE FIRST 72 HRS
OF THE FCST BASED ON THE LATEST HRRR AND THE 00Z NAM. BIGGEST
CHANGES WERE MADE TO POPS AND TEMPS.
UPDATED PRODUCTS WILL BE SENT SHORTLY. /09/
&&
.PREV DISCUSSION... /ISSUED 540 PM CST TUE JAN 19 2016/
AVIATION...
CONDITIONS TO DETERIORATE OVERNIGHT AS A COLD FRONT MOVES ACROSS
THE AREA. CEILINGS TO BECOME MVFR AHEAD OF THE FRONT FOLLOWED BY
AN INCREASE IN COVERAGE OF RAIN SHOWERS AFTER 20/06Z. WINDS TO
BECOME NORTHWEST 5 TO 10 KNOTS BEHIND THE FRONT ACROSS MOST AREAS
BY DAYBREAK. OTHERWISE...IFR CEILINGS AND VISIBILITIES BETWEEN
20/12Z-20/16Z TO GRADUALLY IMPROVE THROUGHOUT THE DAY. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 47 56 50 62 / 40 20 40 50
MLU 48 57 49 65 / 30 40 40 70
DEQ 39 49 40 53 / 40 10 50 60
TXK 41 50 45 56 / 50 10 50 60
ELD 43 52 44 58 / 50 40 50 70
TYR 41 53 49 60 / 40 10 40 40
GGG 43 54 50 61 / 40 10 40 50
LFK 47 59 54 65 / 30 20 30 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
552 PM EST MON JAN 18 2016
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 410 PM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM THE
ERN LAKES INTO NRN NEW ENGLAND WITH A SHORTWAVE TROUGH EXTENDING NW
TO NEAR LAKE SUPERIOR. AT THE SFC...A LAKES AGGREGATE TROUGH EXTENDED
FROM LAKE HURON INTO SRN LAKE SUPERIOR. MULTIPLE WIND PARALLEL LES
BANDS WITH NW ARCTIC FLOW CONTINUED. 850 MB TEMPS AROUND -23C
PROVIDED PLENTIFUL INSTABILITY WITH LAKE INDUCED CAPES INTO THE
500-750 J/KG. THE MID LEVEL SHRTWV AND ASSOCIATED 700-300 MB QVECTOR
CONV HAS ALSO HELPED BOOST INVERSION/EQUILIBRIUM HEIGHTS THIS
AFTERNOON. VIS LOOP...SFC OBS AND WEB CAMS SUGGEST THE HEAVIER LES
WAS OVER THE ERN CWA...IN CLOSER PROXIMITY TO THE SHRTWV AND
DOWNSTREAM FROM THE LONGEST FETCH.
TONIGHT...THE HIGH RES MODELS SUGGEST THAT LOW LEVEL WINDS WILL VEER
SLIGHTLY IN THE WAKE OF THE SHRTWV...HELPING TO PUSH THE MORE
PROMINENT LES BANDS INTO CNTRL AND WRN ALGER COUNTY. WITH ADDITIONAL
SNOWFALL AMOUNTS IN THE 3 TO 7 INCH RANGE EXPECTED...THE LES WARNING
WAS EXTENDED (TIL 12Z) FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WITH
AN THE ADVY INTO SRN SCHOOLCRAFT ALSO EXTENDED TIL 06Z.
OVER THE WEST...INVERSION HEIGHTS DROP OFF TO AROUND 4K FT THIS
EVENING WHICH SHOULD LIMIT LES INTENSITY WITH ADDITIONAL SNOWFALL
AMOUNTS TO ADVY AMOUNTS IN THE 2 TO 5 INCH RANGE OR LESS. THE
STRONGER LOW LEVEL CONV FROM ONTONAGON EASTWARD SHOULD ALSO SAG TO
THE SOUTH THIS EVENING.
TUE...LES SHOULD CONTINUE TO DIMINISH WITH INVERSION HEIGHTS FALLING
TO 3K-4K FT AND WINDS BACKING ACYC WRLY AS A SFC RIDGE BUILDS FROM
THE UPPER MS VALLEY INTO THE WRN LAKES. TEMPS WILL ALSO MODERATE
WITH HIGHS FROM THE LOWER TEENS WEST TO AROUND 20 EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM EST MON JAN 18 2016
THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT
AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S
CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH
WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY
WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL
BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO
THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING
SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE
SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT
LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW
PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS
SFC WINDS SHIFT TO A MORE S-SW DIRECTION.
A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING
WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE
MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP
WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP
THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY
PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING
ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW
ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR
THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY
FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH
1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE
MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY
OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE
CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE
THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC
LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS
TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A
GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES
THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR
OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C.
LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT
TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO
THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO
EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST
OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS
850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE
ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS.
THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N
CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND
ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE
GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE
IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND
INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 552 PM EST MON JAN 18 2016
AT KIWD...EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT IWD
THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW FOR
IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A RETURN
TO VFR CONDITIONS TUE AFTERNOON AS WINDS BACK TO THE SW.
AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR
CONDITIONS IN LAKE EFFECT SNOW INTO THIS EVENING. EXPECT SOME
IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS DIMINISH.
HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN
PREVAILING IFR CONDITIONS THROUGH TUE AFTERNOON.
AT KSAW...EXPECT MVFR THIS EVENING AS WINDS VEER FROM NW TO NNW AND
SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA. BACKING WINDS LATE
TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST MON JAN 18 2016
EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-25 KTS...HIGHEST
OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED WILL ALSO END EARLY THIS EVENING. WINDS ARE EXPECTED TO
SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE
MOVES OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ014.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ263>266.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 PM EST MON JAN 18 2016
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 410 PM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL LOW FROM THE
ERN LAKES INTO NRN NEW ENGLAND WITH A SHORTWAVE TROUGH EXTENDING NW
TO NEAR LAKE SUPERIOR. AT THE SFC...A LAKES AGGREGATE TROUGH EXTENDED
FROM LAKE HURON INTO SRN LAKE SUPERIOR. MULTIPLE WIND PARALLEL LES
BANDS WITH NW ARCTIC FLOW CONTINUED. 850 MB TEMPS AROUND -23C
PROVIDED PLENTIFUL INSTABILITY WITH LAKE INDUCED CAPES INTO THE
500-750 J/KG. THE MID LEVEL SHRTWV AND ASSOCIATED 700-300 MB QVECTOR
CONV HAS ALSO HELPED BOOST INVERSION/EQUILIBRIUM HEIGHTS THIS
AFTERNOON. VIS LOOP...SFC OBS AND WEB CAMS SUGGEST THE HEAVIER LES
WAS OVER THE ERN CWA...IN CLOSER PROXIMITY TO THE SHRTWV AND
DOWNSTREAM FROM THE LONGEST FETCH.
TONIGHT...THE HIGH RES MODELS SUGGEST THAT LOW LEVEL WINDS WILL VEER
SLIGHTLY IN THE WAKE OF THE SHRTWV...HELPING TO PUSH THE MORE
PROMINENT LES BANDS INTO CNTRL AND WRN ALGER COUNTY. WITH ADDITIONAL
SNOWFALL AMOUNTS IN THE 3 TO 7 INCH RANGE EXPECTED...THE LES WARNING
WAS EXTENDED (TIL 12Z) FOR ALGER AND NRN SCHOOLCRAFT COUNTIES WITH
AN THE ADVY INTO SRN SCHOOLCRAFT ALSO EXTENDED TIL 06Z.
OVER THE WEST...INVERSION HEIGHTS DROP OFF TO AROUND 4K FT THIS
EVENING WHICH SHOULD LIMIT LES INTENSITY WITH ADDITIONAL SNOWFALL
AMOUNTS TO ADVY AMOUNTS IN THE 2 TO 5 INCH RANGE OR LESS. THE
STRONGER LOW LEVEL CONV FROM ONTONAGON EASTWARD SHOULD ALSO SAG TO
THE SOUTH THIS EVENING.
TUE...LES SHOULD CONTINUE TO DIMINISH WITH INVERSION HEIGHTS FALLING
TO 3K-4K FT AND WINDS BACKING ACYC WRLY AS A SFC RIDGE BUILDS FROM
THE UPPER MS VALLEY INTO THE WRN LAKES. TEMPS WILL ALSO MODERATE
WITH HIGHS FROM THE LOWER TEENS WEST TO AROUND 20 EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM EST MON JAN 18 2016
THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT
AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S
CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH
WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY
WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL
BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO
THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING
SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE
SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT
LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW
PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS
SFC WINDS SHIFT TO A MORE S-SW DIRECTION.
A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING
WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE
MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP
WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP
THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY
PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING
ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW
ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR
THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY
FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH
1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE
MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY
OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE
CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE
THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC
LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS
TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A
GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES
THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR
OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C.
LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT
TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO
THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO
EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST
OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS
850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE
ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS.
THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N
CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND
ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE
GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE
IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND
INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 110 PM EST MON JAN 18 2016
AT KIWD...WINDS VEERING MORE NW LATE THIS AFTERNOON WILL LOWER
CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT
SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT
IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW
FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A
RETURN TO VFR CONDITIONS TUE MORNING AS WINDS BACK TO THE SW.
AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR
CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY INTO THIS EVENING.
EXPECT SOME IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS
DIMINISH. HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL
RESULT IN PREVAILING IFR CONDITIONS THROUGH TUE MORNING.
AT KSAW...EXPECT MAINLY CIGS NEAR 3K FT...BORDERLINE MVFR...THIS
AFTERNOON BUT THEN EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS
EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW
BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT
AGAIN TO VFR.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST MON JAN 18 2016
EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-25 KTS...HIGHEST
OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED WILL ALSO END EARLY THIS EVENING. WINDS ARE EXPECTED TO
SLOWLY DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE
MOVES OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ014.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ263>266.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
350 PM EST MON JAN 18 2016
.DISCUSSION...
LAKE EFFECT SNOW SHOWERS WILL HOLD WITH SCATTERED TO NUMEROUS
COVERAGE AND LIGHT TO MODERATE INTENSITY FOR THE REST OF THE
AFTERNOON THROUGH MID EVENING. THE MOST RECENT RAP SOUNDINGS
INDICATE CONVECTIVE DEPTH SETTLING STEADILY BELOW 5000 FT BETWEEN
21Z AND 03Z BUT WITH NEARLY DRY ADIABATIC LAPSE RATE AND HIGH ICE
SUPERSATURATION WITHIN THE CLOUD LAYER FOR HEALTHY GROWTH OF
DENDRITES. THAT BEING SAID...SURFACE DEWPOINT AROUND -10F REPORTED
UPSTREAM OF LAKE MICHIGAN HAS TO BE CONSIDERED A LIMITING FACTOR FOR
LAKE INDUCED CONVECTIVE POTENTIAL THIS FAR EAST. ON THE POSITIVE
SIDE...MID TO LATE AFTERNOON SURFACE OBSERVATIONS ON THIS SIDE OF
THE LAKE CONTINUE TO ADVERTISE GUSTY WEST FLOW WITH A GREATER AMOUNT
OF CONVERGENCE DOWN WIND OF LAKE MICHIGAN THAN WOULD NORMALLY BE
EXPECTED IN WELL MIXED MID AFTERNOON CONDITIONS. THIS WILL KEEP
COVERAGE WITH BETTER INTENSITY FOCUSED GENERALLY ALONG AND SOUTH OF
THE I-96 TO I-94 CORRIDOR. FACTORING IN THE DRY NATURE OF THE ARCTIC
AIR AND STEADILY SHRINKING CONVECTIVE DEPTH...EXPECT ACCUMULATION
LIMITED TO LESS THAN AN INCH EVEN WITH NUMEROUS COVERAGE AND/OR A
STREAMER OF GREATER FOCUSED BANDING AT TIMES BEFORE DIMINISHING
TOWARD MIDNIGHT.
THE UPPER LEVEL TROUGH WILL SWING SOUTH OF LOWER MICHIGAN SHORTLY
AFTER MIDNIGHT AND WILL SHUT DOWN LAKE EFFECT PRODUCTION. STRONG
SUBSIDENCE TRAILING THE UPPER TROUGH AND PRECEDING THE RIDGE AXIS
WILL ALSO SUPPORT A CLEARING TREND MUCH LIKE WHAT OCCURRED EARLY
THIS MORNING. THIS WILL ALLOW ANOTHER ROUND OF SINGLE DIGIT MIN
TEMPS OUTSIDE OF METRO DETROIT AND MAINTAIN WIND CHILL NEAR 10
BELOW AT TIMES THROUGH TUESDAY MORNING. FORECAST CONCERNS WILL THEN
BE REDUCED TO CLOUD AND TEMPERATURE TRENDS DURING THE REST OF
TUESDAY AND TUESDAY NIGHT. BACKING LOW LEVEL FLOW WILL DIRECT
REMAINING LAKE EFFECT CLOUDS MAINLY INTO THE TRI CITIES BEFORE HIGH
PRESSURE BUILDS OVER THE REGION BY EVENING. LIGHTER WIND WILL MAKE
MAX TEMPS IN THE LOWER 20S EASIER TO TAKE COMPARED TO RECENT DAYS.
BENIGN CONDITIONS WILL CONTINUE THROUGH TUESDAY NIGHT AS HIGH CLOUDS
THICKEN AND LOWER IN ADVANCE OF THE NEXT LOW PRESSURE SYSTEM. THE
NEW MODEL PACKAGE IS IN GOOD AGREEMENT HOLDING OFF SNOW UNTIL
WEDNESDAY MORNING...MAINLY AFTER THE MORNING DRIVE...AND THEN
LEAVING UP TO AN INCH OF ACCUMULATION BEFORE ENDING BY MIDNIGHT
WEDNESDAY NIGHT. EXPECT THIS TO BE MOSTLY A MID LEVEL ISENTROPIC
LIFT DRIVEN EVENT AS MODEL DEPICTIONS OF THE 500 MB HEIGHT FIELD
SHOW CONSOLIDATION OF SHORT WAVES IN THE FLOW BUT WITH FRAGMENTED
DYNAMIC SUPPORT IN TERMS OF DCVA. THE LOW LEVEL FRONTAL ZONE IS ALSO
LOCATED WELL SOUTH INTO THE OHIO AND TENNESSEE VALLEYS JUDGING BY
1000-850 MB THICKNESS. THIS DOES NOT PREVENT ADEQUATE MOISTURE FROM
REACHING THIS FAR NORTH AS SPECIFIC HUMIDITY AVERAGES 1-2 G/KG UP TO
700 MB OVER LOWER MICHIGAN. IT DOES INDICATE THE SHALLOW AND STABLE
NATURE OF THE SYSTEM RELATIVE ISENTROPIC LIFT. AS MENTIONED IN THE
PREVIOUS DISCUSSION...MODEL SOUNDINGS DO INDICATE A DEEP ISOTHERMAL
PROFILE WITHIN THE DGZ BELOW 600 MB WHICH WILL GIVE A BOOST TO SNOW
RATIO AND POTENTIAL OVERACHIEVEMENT. THE COLLABORATED QPF ADJUSTMENTS
MADE IN THE PREVIOUS FORECAST CYCLE ARE THUS PRESERVED FOR THIS
PACKAGE.
EXTENDED THURSDAY THROUGH TUESDAY... AS WEDNESDAY`S WAVE OF LOW
PRESSURE EXITS THE REGION...A SLIGHT CHANCE OF SNOW SHOWERS WILL
REMAIN IN THE FORECAST THROUGH EARLY THURSDAY MORNING. BRIEF HIGH
PRESSURE BUILDS OVER THE AREA DURING THE DAY ON THURSDAY. THIS
HIGH PRESSURE IS EXPECTED TO PRODUCE A DECENT DRY DAY WITH MOSTLY
TO PARTLY CLOUDY SKIES OVER THE WHOLE OF SOUTHEAST MICHIGAN. AN
UPPER LEVEL TROUGH SWINGS ACROSS THE NORTHERN THUMB AREAS ON
FRIDAY...GENERATING ANOTHER WEAK SHOT AT SNOW SHOWERS. HIGH
PRESSURE IS ON TAP TO RETURN FOR THE WEEKEND. TEMPERATURE
CONTINUES TO WARM THROUGH THE PERIOD WITH HIGHS EDGING INTO THE
MID 30`S BY SUNDAY OVER SOUTHERN HALF OF THE CWA.
&&
.MARINE...
A SURFACE TROUGH SLOWLY DROPPING THROUGH LAKE HURON WILL MAINTAIN
STRONG WESTERLY WINDS THROUGH THE REMAINDER OF THE AFTERNOON AND
EVENING OVER SOUTHERN LAKE HURON...LAKE ST CLAIR...AND WESTERN LAKE
ERIE. WINDS WILL BE STRONGEST OVER THE SOUTHERN THIRD OF LAKE
HURON...WHERE GUSTS WILL PRIMARILY REMAIN AROUND 30 KNOTS...BUT A
FEW GUSTS TO GALE FORCE ARE POSSIBLE. SMALL CRAFT ADVISORIES REMAIN
IN EFFECT FOR THE NEARSHORE WATERS OF LAKE HURON FROM OUTER SAGINAW
BAY DOWN TO PORT HURON. THE REMAINDER OF THE NEARSHORE WATERS ARE
ICE COVERED AND THEREFORE REMAIN WITHOUT A HEADLINE. WINDS WILL
DECREASE EARLY TONIGHT AS THE SURFACE TROUGH DROPS SOUTHWARD.
IN ADDITION...THE STRONG WINDS AND ARCTIC AIRMASS IN PLACE WILL
CREATE FAVORABLE CONDITIONS FOR FREEZING SPRAY TO DEVELOP OVER LAKE
HURON THROUGH TUESDAY...ESPECIALLY ACROSS THE OPEN WATERS. INTENSITY
LOOKS TO ONLY REMAIN MODERATE HOWEVER.
WINDS WILL REMAIN A LITTLE GUSTY OUT OF THE NORTHWEST ACROSS LAKE
HURON TUESDAY BEFORE HIGH PRESSURE BUILDING INTO THE CENTRAL GREAT
LAKES AND OHIO VALLEY BRINGS LIGHTER WIND CONDITIONS FROM LATE
TUESDAY INTO WEDNESDAY.
&&
.AVIATION...ISSUED 1243 PM EST MON JAN 18 2016
ARCTIC AIRMASS AND SURFACE WIND CONVERGENCE OVER SOUTHERN MICHIGAN
WILL PROMOTE THE SPREAD OF LAKE EFFECT SNOW SHOWERS EASTWARD INTO
THE DETROIT AREA TERMINALS. LATEST SATELLITE AND RADAR FAVORED
SHOWERS OCCURRING ANYTIME AFTER 18Z...WITH POTENTIAL FOR OCCASIONAL
SHOWERS TO AFFECT TERMINALS FROM PTK SOUTH THROUGH THIS EVENINGS.
CEILINGS ARE EXPECTED TO PREVAIL AT VFR ACROSS SOUTHEAST MICHIGAN
THIS AFTERNOON AND EVENING...WITH OCCASIONAL DROPS TO MVFR IN LAKE
EFFECT SHOWERS. CONFIDENCE IN PREVAILING CEILINGS AT 3500 FEET IS
NOT HIGH HOWEVER...AS THERE IS SOME UNCERTAINTY WITH HOW FAR
EASTWARD FROM THE LAKE A 2500 FT CEILING OVER THE WEST SIDE OF THE
STATE WILL PENETRATE. TIGHT SURFACE PRESSURE GRADIENT WILL MAINTAIN
GUSTY WEST WINDS...WITH GUSTS PEAKING AROUND 25 KNOTS THIS
AFTERNOON. HIGH PRESSURE SLOWLY BUILDING INTO THE WESTERN GREAT
LAKES WILL DECREASE POTENTIAL FOR LAKE EFFECT SHOWERS TONIGHT...THEN
BRING DRY VFR CONDITIONS TOMORROW AS IT SETTLES IN OVER THE OHIO
VALLEY AND CENTRAL GREAT LAKES.
FOR DTW...TIGHT SURFACE PRESSURE GRADIENT WILL MAINTAIN STRONG WEST
WIND GUSTS (TO 25 KNOTS) THROUGH EARLY EVENING...WITH DIRECTION AT
250-260 KEEPING WINDS SHY OF CROSSWIND THRESHOLDS. SOME UNCERTAINTY
WITH CEILING HEIGHTS TODAY (NOTE ABOVE)...BUT DO EXPECT TO SEE SOME
DROPS TO MVFR IN OCCASIONAL LAKE EFFECT SNOW SHOWERS THAT WILL
AFFECT THE TERMINAL AND AIRSPACE. SNOW ACCUMULATIONS WILL BE VERY
LIGHT IF WE DO SEE ANY GOOD BURSTS.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING AOB 5000 FT THROUGH LATE TONIGHT.
* HIGH FOR SNOW AS PRECIPITATION TYPE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LHZ421-
441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
DISCUSSION...BT/DE
MARINE.......HLO
AVIATION.....HLO
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
325 PM EST MON JAN 18 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 558 AM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW
JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED
BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN
ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO
ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER
MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS
SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO
NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL
PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST
LOW-LEVEL CONVERGENCE SETS UP.
WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI
BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR
THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO
WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE
MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20
RANGE THIS MORNING.
TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING
SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING.
AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH
INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO
AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY
LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY
AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION
HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE.
ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR
ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN
SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING
AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER
THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG
CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL
SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM
PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR
NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL
CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES
OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING.
TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND
SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT
MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW-
LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY
INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY
SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE
AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED
THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR
GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE
DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH
SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW
FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE
TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND
THEN BACK INTO ERN ALGER AND LUCE COUNTIES.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 PM EST MON JAN 18 2016
THE 500MB RIDGE OVERHEAD ON TUESDAY WILL SLOWLY EXIT E TUESDAY NIGHT
AND WEDNESDAY IN RESPONSE TO THE ELONGATED TROUGH EXTENDING FROM S
CENTRAL CANADA THROUGH W MN AND IA AT 00Z WEDNESDAY. THIS TROUGH
WILL SLIDE ACROSS THE UPPER GREAT LAKES DURING THE DAY
WEDNESDAY...AND TO THE LOWER GREAT LAKES 00-06Z THURSDAY. THIS WILL
BY WHILE THE LARGE SFC HIGH STRETCHING FROM THE UPPER GREAT LAKES TO
THE TIP OF FL AT 00Z WEDNESDAY SLOWLY BECOMES SUPRESSED TO THE SE. LOOKING
SPECIFICALLY AT THE LINGERING LAKE INDUCED TROUGH OVER LAKE
SUPERIOR...IT WILL SLOWLY DEEPEN OVERNIGHT AND INTO THURSDAY. EXPECT
LINGERING LES BANDS TO SHIFT ACROSS THE TIP OF THE KEWEENAW
PENINSULA AND FAR N LUCE COUNTY...AND EVENTUALLY OFFSHORE AS
SFC WINDS SHIFT TO A MORE S-SW DIRECTION.
A SHORTWAVE PUSHING ACROSS THE PACIFIC NORTHWEST WEDNESDAY MORNING
WILL LIVE ACROSS THE PLAINS STATES WEDNESDAY NIGHT WHILE A N WAVE
MOVES ACROSS LAKE SUPERIOR/UPPER MI. BY 00Z THURSDAY THE SFC MAP
WILL SHOW THE NEXT LOW OVER FAR E CO WILL HAVE AN INVERTED TROUGH UP
THROUGH SW MN AND W ONTARIO. THE N LOW WILL BE FAIRLY
PROGRESSIVE...MOVING OVER LAKE SUPERIOR BY 12Z THURSDAY AND EXITING
ACROSS LOWER MI THURSDAY NIGHT...MERGING WITH THE STRONGER LOW
ACROSS TN. THIS WILL BRING THE BEST CHANCE OF WIDESPREAD SNOW FOR
THIS LONG TERM PERIOD...WILL LIKELY BE LATE THURSDAY INTO EARLY
FRIDAY. AT THIS POINT THE GFS IS THE MOST ROBUST WITH THE SNOW WITH
1-4IN CWA WIDE. THE ON THE POSITIVE SIDE THE DGZ IS WITHIN THE
MOISTURE LAYER...BUT INVERSION HEIGHTS LOOK TO FALL PRETTY QUICKLY
OVERNIGHT THURSDAY NIGHT INTO FRIDAY MORNING. FAVORABLE UPSLOPE
CONDITIONS FOR LES DO NOT SEEM TO RETURN TO THE CWA UNTIL LATE
THURSDAY AFTERNOON IN THE FORM OF NW WIND BEHIND THE EXITING SFC
LOW. THEY WILL NOT BE ALL THAT STEADY FOR SIGNIFICANT DOMINANT BANDS
TO DEVELOP AS WINDS SHIFT OUT OF THE N-NNE BY DAYBREAK FRIDAY. A
GENERAL 500MB TROUGH WILL BE SETUP ACROSS THE UPPER GREAT LAKES
THROUGH THE GULF OF MEXICO W THURSDAY-FRIDAY...KEEPING COOLER AIR
OVER THE AREA. 850MB TEMPS WILL REMAIN -7 TO -14C.
LOOK FOR A SIGNIFICANT RIDGE OF HIGH PRESSURE AT 500MB FRIDAY NIGHT
TO EXTEND FROM THE INTERIOR SW UP THROUGH THE PLAINS TO PUSH INTO
THE UPPER GREAT LAKES AS THE S TROUGH DEEPENS TO A LOW AND BEGINS TO
EXIT OFF THE MID ATLANTIC SEABOARD. THIS 500MB LOW WILL PUSH N JUST
OFF THE NEW ENGLAND COAST BY SUNDAY MORNING. WAA WILL RESULT...AS
850MB TEMPS RISE TO -5 TO -10C BY 06Z SATURDAY /WARMEST OFF THE
ECMWF/...AND -1 TO -5C BY 00Z SUNDAY ON SW 850MB WINDS NEARING 35KTS.
THERE ARE SOME DIFFERENCES IN THE HANDLING OF THE 500MB LOW OVER N
CANADA FOR THE END OF THE UPCOMING WEEKEND. WHILE BOTH THE GFS AND
ECMWF SHOW A DEEP TROUGH SWINGING ACROSS MUCH OF THE NATION...THE
GFS IS FARTHER S WITH THIS FEATURE. EXPECT SOME STEADY SNOW TO SLIDE
IN FROM THE S SUNDAY EVENING INTO EARLY MONDAY...BUT TIMING AND
INTENSITY COULD CHANGE SIGNIFICANTLY BETWEEN NOW AND THEN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 110 PM EST MON JAN 18 2016
AT KIWD...WINDS VEERING MORE NW LATE THIS AFTERNOON WILL LOWER
CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT
SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT
IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW
FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A
RETURN TO VFR CONDITIONS TUE MORNING AS WINDS BACK TO THE SW.
AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR
CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY INTO THIS EVENING.
EXPECT SOME IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS
DIMINISH. HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL
RESULT IN PREVAILING IFR CONDITIONS THROUGH TUE MORNING.
AT KSAW...EXPECT MAINLY CIGS NEAR 3K FT...BORDERLINE MVFR...THIS
AFTERNOON BUT THEN EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS
EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW
BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT
AGAIN TO VFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 558 AM EST MON JAN 18 2016
A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED
A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO
LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-
25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY
FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY
DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES
OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR MIZ014.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ263>266.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
111 PM EST MON JAN 18 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 558 AM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW
JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED
BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN
ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO
ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER
MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS
SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO
NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL
PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST
LOW-LEVEL CONVERGENCE SETS UP.
WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI
BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR
THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO
WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE
MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20
RANGE THIS MORNING.
TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING
SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING.
AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH
INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO
AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY
LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY
AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION
HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE.
ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR
ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN
SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING
AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER
THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG
CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL
SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM
PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR
NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL
CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES
OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING.
TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND
SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT
MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW-
LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY
INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY
SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE
AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED
THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR
GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE
DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH
SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW
FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE
TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND
THEN BACK INTO ERN ALGER AND LUCE COUNTIES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 420 AM EST MON JAN 18 2016
...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND...
UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND
MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW
DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT
SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION
BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND
WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL
WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE
RECENT CHILL WITH THIS ARCTIC AIRMASS.
STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A
DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD
LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE
FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2
INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT.
AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK
MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM
MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE
EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT.
APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH
MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE
NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE
EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR
RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE
SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND
GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF
THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT.
SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY
NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A
BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH.
ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO
THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE
OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF
LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO
FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT
HAVE SOME SMALL CHANCE POPS.
HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE
PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING
WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT
AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE
OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL
COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE
EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS
IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF
EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND
WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY
SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO
JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT
SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS
HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR
20S/LOWER 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 110 PM EST MON JAN 18 2016
AT KIWD...WINDS VEERING MORE NW LATE THIS AFTERNOON WILL LOWER
CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT
SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT
IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW
FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS. EXPECT A
RETURN TO VFR CONDITIONS TUE MORNING AS WINDS BACK TO THE SW.
AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR
CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY INTO THIS EVENING.
EXPECT SOME IMPROVEMENT BY LATE EVENING AND OVERNIGHT AS WINDS
DIMINISH. HOWEVER...CONTINUED LAKE EFFECT SNOW SHOWERS WILL STILL
RESULT IN PREVAILING IFR CONDITIONS THROUGH TUE MORNING.
AT KSAW...EXPECT MAINLY CIGS NEAR 3K FT...BORDERLINE MVFR...THIS
AFTERNOON BUT THEN EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS
EVENING AS WINDS VEER FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW
BRUSHES THE AREA. BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT
AGAIN TO VFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 558 AM EST MON JAN 18 2016
A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED
A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO
LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-
25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY
FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY
DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES
OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002-
003-006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-
014-084.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ263>266.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
744 AM EST MON JAN 18 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 558 AM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW
JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED
BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN
ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO
ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER
MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS
SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO
NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL
PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST
LOW-LEVEL CONVERGENCE SETS UP.
WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI
BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR
THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO
WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE
MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20
RANGE THIS MORNING.
TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING
SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING.
AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH
INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO
AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY
LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY
AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION
HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE.
ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR
ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN
SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING
AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER
THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG
CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL
SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM
PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR
NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL
CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES
OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING.
TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND
SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT
MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW-
LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY
INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY
SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE
AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED
THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR
GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE
DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH
SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW
FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE
TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND
THEN BACK INTO ERN ALGER AND LUCE COUNTIES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 420 AM EST MON JAN 18 2016
...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND...
UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND
MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW
DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT
SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION
BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND
WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL
WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE
RECENT CHILL WITH THIS ARCTIC AIRMASS.
STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A
DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD
LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE
FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2
INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT.
AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK
MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM
MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE
EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT.
APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH
MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE
NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE
EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR
RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE
SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND
GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF
THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT.
SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY
NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A
BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH.
ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO
THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE
OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF
LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO
FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT
HAVE SOME SMALL CHANCE POPS.
HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE
PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING
WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT
AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE
OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL
COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE
EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS
IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF
EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND
WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY
SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO
JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT
SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS
HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR
20S/LOWER 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 733 AM EST MON JAN 18 2016
AT KIWD...WINDS VEERING MORE NW LATER THIS AFTERNOON WILL LOWER
CONDITIONS FROM GENERALLY MVFR TO IFR AS MORE PERSISTENT LAKE EFFECT
SNOW MOVES IN. EXPECT IFR VSBY/CISG DURING THE HEAVIER SNOW BANDS AT
IWD THIS EVENING...BUT THEN WINDS BACKING LATE TONIGHT WILL ALLOW
FOR IMPROVEMENT TO MVFR IN LIGHTER LAKE EFFECT SHOWERS.
AT KCMX... GUSTY NW WINDS WILL ALLOW FOR PERSISTENT IFR/LIFR
CONDITIONS IN LAKE EFFECT SNOW AND BLSN TODAY. EXPECT SOME
IMPROVEMENT LATER THIS EVENING AS WINDS DIE DOWN ALTHOUGH CONTINUED
LAKE EFFECT SNOW SHOWERS WILL STILL RESULT IN PREVAILING IFR
CONDITIONS.
AT KSAW...MVFR CONDITIONS WILL IMPROVE TO VFR BY AFTERNOON BUT THEN
EXPECT CONDITIONS TO GO BACK DOWN TO MVFR THIS EVENING AS WINDS VEER
FROM NW TO NNW AND SOME LIGHT LAKE EFFECT SNOW BRUSHES THE AREA.
BACKING WINDS LATE TONIGHT WILL ALLOW IMPROVEMENT AGAIN TO VFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 558 AM EST MON JAN 18 2016
A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED
A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO
LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-
25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY
FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY
DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES
OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002-
003-006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-
014-084.
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
LSZ263>267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
558 AM EST MON JAN 18 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 558 AM EST MON JAN 18 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW
JUST NE OF LAKE HURON. AT THE SFC...NW LOW LEVEL FLOW PREVAILED
BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY TO SRN
ONTARIO. RADAR AND IR LOOP SHOWED WIND PARALLEL MULTI-BAND LES INTO
ALGER...SCHOOLCRAFT AND LUCE COUNTIES AND INTO WRN COUNTIES OF UPPER
MI AS WELL. WITH 850/700 MB TEMPS AROUND -23C/-28C MODEL SOUNDINGS
SHOW LAKE INDUCED CAPES NEAR 500 J/KG AND EQUILIBRIUM HEIGHTS TO
NEAR 10K FT...NOT QUITE AS UNSTABLE AS OVER THE WEEKEND BUT STILL
PLENTY UNSTABLE FOR MODERATE TO POSSIBLY HEAVY LES BANDS WHERE BEST
LOW-LEVEL CONVERGENCE SETS UP.
WITH SINGLE DIGIT BLO ZERO TEMPS FALLING NEAR -10F ALONG THE WI
BORDER EXPECT ADVISORY CRITERIA WIND CHILLS IN -20 TO -30 RANGE NEAR
THE WI BORDER FROM IRONWOOD TO CRYSTAL FALLS INTO MIDDAY TODAY SO
WIND CHILL ADVISORY HEADLINE REMAINS IN EFFECT. EXPECT ENOUGH LAKE
MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY IN THE -10 TO -20
RANGE THIS MORNING.
TODAY...MODELS INDICATE SHRTWV JUST SOUTH OF JAMES BAY WILL SWING
SOUTH ACROSS ERN LAKE SUPERIOR LATER THIS AFTERNOON AND EVENING.
AHEAD OF THIS FEATURE MODELS SUGGEST POTENTIAL FOR ENHANCEMENT WITH
INCREASING Q-VECT CONV OVER ERN LAKE SUPERIOR THIS MORNING INTO
AFTERNOON. CONDITIONS WILL REMAIN FAVORABLE FOR MODERATE TO HEAVY
LES WITH PROBABLY AN UPTICK IN LES INTENSITY BY LATE MORNING/EARLY
AFTERNOON INTO ERN COUNTIES ALONG LAKE SUPERIOR WHERE INVERSION
HEIGHTS REMAIN HIGH AND DENDRITIC SNOW GROWTH STILL FAVORABLE.
ONGOING WARNINGS WILL REMAIN IN EFFECT THROUGH THE DAY FOR
ALGER...LUCE AND NRN SCHOOLCRAFT WITH ADVISORY IN EFFECT FOR SRN
SCHOOLCRAFT. COULD SEE ADDITIONAL SNOW ACCUMULATION INTO WARNING
AREAS APPROACHING A FOOT INTO THIS EVENING. ALTHOUGH CONDITIONS OVER
THE WEST WILL BE LESS FAVORABLE WITH SHORTER FETCH LENGTH...STRONG
CONVERGENCE COULD LEAD TO FORMATION OF STRONGER BANDS AND ADDITIONAL
SNOW ACCUMULATION OF NEAR 10 INCHES INTO THIS EVENING FOR AREAS FROM
PORCUPINE MTNS NE TO NEAR TWIN LAKES. SO WILL CONTINUE WARNING FOR
NRN HOUGHTON AND ONTONAGON COUNTIES THROUGH TODAY. ADVISORIES WILL
CONTINUE FOR SRN HOUGHTON AND KEWEENAW COUNTIES WHERE 3 TO 7 INCHES
OF ADDITIONAL ACCUMULATION IS EXPECTED TODAY INTO THIS EVENING.
TONIGHT...WINDS BRIEFLY SHIFT MORE NORTHERLY THIS EVENING BEHIND
SHORTWAVE AND ASSOC SFC TROUGH PASSAGE WHICH COULD FOCUS LES A BIT
MORE INTO WRN ALGER AND PERHAPS FAR ERN MQT COUNTY WHERE BETTER LOW-
LVL CONVERGENCE SETS UP. WILL LIKELY NEED TO EXTEND A LES ADVISORY
INTO AT LEAST ALGER AND MAYBE NRN SCHOOLCRAFT TONIGHT. NORTHERLY
SHIFT IN WINDS WILL GENERALLY SHIFT HEAVIER LES BANDS OUT OF LUCE
AND SRN SCHOOLCRAFT COUNTIES...SO HEADLINES WILL LIKELY BE DROPPED
THERE AFTER TODAY. LES ADVISORIES MAY BE NEEDED THIS EVENING FOR
GOGEBIC AND ONTONAGON COUNTIES IN WEST BUT ADVISORIES WILL LIKELY BE
DROPPED FOR HOUGHTON AND MAYBE KEWEENAW COUNTIES AS WELL WITH
SHORTENED FETCH ACROSS WATER DUE TO ISLE ROYALE IN DEVELOPING NNW
FLOW. BEHIND TROUGH PASSAGE WINDS WILL AGAIN BACK MORE WNW LATE
TONIGHT SHIFTING MODERATE LES BANDS INTO THE KEWEENAW PENINSULA AND
THEN BACK INTO ERN ALGER AND LUCE COUNTIES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 420 AM EST MON JAN 18 2016
...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND...
UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND
MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW
DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT
SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION
BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND
WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL
WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE
RECENT CHILL WITH THIS ARCTIC AIRMASS.
STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A
DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD
LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE
FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2
INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT.
AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK
MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM
MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE
EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT.
APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH
MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE
NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE
EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR
RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE
SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND
GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF
THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT.
SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY
NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A
BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH.
ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO
THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE
OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF
LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO
FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT
HAVE SOME SMALL CHANCE POPS.
HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE
PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING
WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT
AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE
OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL
COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE
EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS
IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF
EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND
WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY
SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO
JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT
SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS
HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR
20S/LOWER 30S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 353 AM EST MON JAN 18 2016
AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT.
EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY
MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH
THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION.
AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST
PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST
WITH NORTHWEST WINDS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 558 AM EST MON JAN 18 2016
A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR TODAY. HAVE ISSUED
A GALE WARNING TODAY FOR LSZ265-266 WITH GALE FORCE GUSTS INTO
LSZ264. OTHERWISE EXPECT WINDS TO DIMINISH LATER THIS EVENING TO 20-
25 KTS...HIGHEST OVER ERN LAKE SUPERIOR. IN ADDITION...HEAVY
FREEZING SPRAY IS EXPECTED TODAY. WINDS ARE EXPECTED TO SLOWLY
DIMINISH TOWARDS THE MIDDLE OF THE WEEK...AS HIGH PRESSURE MOVES
OVER THE UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002-
003-006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-
014-084.
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
LSZ263>267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 AM EST MON JAN 18 2016
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 408 PM EST SUN JAN 17 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW
JUST TO THE EAST OF LAKE SUPERIOR. AT THE SFC...NW LOW LEVEL FLOW
PREVAILED BTWN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY
TO SRN ONTARIO. RADAR AND VIS LOOP SHOWED MAINLY MULTI-BAND LES WITH
FEW DOMINANT OR COHERENT BANDSAS THE LES INTENSITY HAS DIMINISHED
SLIGHTLY WITH THE VERY DRY ARCTIC AIR UPSTREAM AND THE LAKES
AGGREGATE TROUGH SHIFTING TO THE SOUTH OF UPPER MICHIGAN.
INSTABILITY OVER THE LAKE REMAINED HIGH WITH 850/700 MB TEMPS AROUND
-23C/-30C RESULTING IN LAKE INDUCED CAPES NEAR 1K J/KG AND
EQUILIBRIUM HEIGHTS TO 14K FT.
TONIGHT...EXPECT MODERATE TO OCCASIONALLY HEAVY LES TO CONTINUE FOR
NW FLOW FAVORED LOCATIONS. THE HIGH RES MODELS SUGGEST THAT THE MOST
LOW LEVEL CONV OVER THE WEST WILL FOCUS INTO ONTONAGON COUNTY THIS
EVENING. OVER THE EAST...MORE DOMINANT BANDS COULD OVER A WIDER AREA
FROM FROM ALGER COUNTY INTO LUCE COUNTY. LES INTENSITY SHOULD ALSO
INCREASE WITH A SHRTWV OVER NRN ONTARIO ROTATING TO NEAR ERN LAKE
SUPERIOR BY 12Z. HOWEVER...WINDS WILL ALSO BACK SLIGHTLY IN RESPONSE
TO THE INCOMING SHRTWV. ALTHOUGH SNOWFALL AMOUNTS MAY NOT BE AS HEAVY
AS LAST NIGHT...5 TO 9 INCH AMOUNTS WILL BE POSSIBLE OVER THE EAST.
THE SHORTER FETCH AND SLIGHTLY LOWER INVERSION HEIGHTS OVER THE WEST
SHOULD KEEP AMOUNTS IN THE 2 TO 5 INCH RANGE. ENOUGH OF THE
CONVECTIVE LAYER WILL REACH INTO THE DGZ TO KEEP SLR VALUES AOA 25/1.
THE VERY COLD AIR MOVING INTO INTERIOR LOCATIONS WILL DROP WIND
CHILLS INTO THE -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO
CRYSTAL FALLS TONIGHT WHERE A WIND CHILL ADVY REMAINS IN EFFECT.
EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY
IN THE -10 TO -20 RANGE.
MONDAY...AS THE SHRTWV MOVES IN WITH THE STRONGER FORCING SHIFTING
TO THE SOUTH...WINDS WILL GRADUALY VEER. CONDITIONS WILL REMAIN
FAVORABLE FOR MODERATE TO HEAVY LES...AGAIN HEAVIEST OVER THE EAST
WITH SLIGHTLY HIGHER INVERSION HEIGHTS AND LONGER FETCH LENGTHS.
WARNINGS AND ADVISORIES WILL REMAIN IN EFFECT THROUGH THE DAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 420 AM EST MON JAN 18 2016
...LAKE EFFECT SETTLES DOWN THEN A WARMING TREND BY NEXT WEEKEND...
UPPER LOW AND COLD AIR THAT HAVE BEEN OVER REGION THIS PAST WEEKEND
MOVES TO EASTERN CANADA TUE/WED WHILE AN AMPLIFIED BUT ZONAL FLOW
DEVELOPS ACROSS MUCH OF THE CONUS THE REST OF THE WEEK. SOME LIGHT
SNOW IS POSSIBLE AS SHORTWAVES AND WEAK SFC TROUGHS CROSS THE REGION
BUT THIS WILL BE PRETTY QUIET COMPARED TO THE VERY ACTIVE WEEKEND
WITH SIGNIFICANT LAKE EFFECT FOR PARTS OF UPR MICHIGAN. A GENERAL
WARMING TREND WILL OCCUR THROUGH THE WEEK...AT LEAST COMPARED TO THE
RECENT CHILL WITH THIS ARCTIC AIRMASS.
STARTING OFF ON TUE NW FLOW LAKE EFFECT WILL BE ONGOING BUT IN A
DIMINISHED STATE WITH INVERSIONS FALLING BLO 4KFT. ALL THE CLOUD
LAYER WILL BE WITHIN THE DGZ THOUGH SO KEPT POPS HIGH DUE TO THE
FLUFFY SNOW. EVEN SO...DAYTIME TOTALS ON TUE SHOULD BE LESS THAN 2
INCHES MOST AREAS WITH WEAKENING CONVERGENCE COMPARED TO MON NIGHT.
AS SFC WINDS AND EVENTUALLY WINDS NEAR CLOUD LAYER TOP H925-H9 BACK
MORE SW...SHIFTED HIGHER POPS IN THE AFTN OVER KEWEENAW AND FM
MUNISING EASTWARD...THEN CLOUD LAYER WINDS BACK ENOUGH TO END LAKE
EFFECT EVEN OVER KEWEENAW AND EAST OF MUNISING OVERNIGHT TUE NIGHT.
APPROACHING SHORTWAVE TROUGH OVER THE NORTHERN PLAINS ALONG WITH
MOISTURE ADVECTION AND WEAK LIFT IN MID LEVELS MOVES IN LATE TUE
NIGHT. WHERE LAKE EFFECT SNOW SHOWERS AND CLOUDS ARE NON ISSUE TUE
EVENING MAY SEE TEMPS DROP QUICKLY BLO ZERO BEFORE BECOMING STEADY OR
RISING SOME LATE. SOUNDINGS FM NAM/GFS SHOW DRY AIR BLO 5KFT AS THE
SYSTEM APPROACHES AND THE LIFT ALOFT IS WEAK AS STRONGER LIFT AND
GREATER MOISTENING REMAINS WELL TO THE SOUTH OF UPR MICHIGAN. BOTH OF
THESE FACTORS WILL LIMIT OVERALL CHANCE OF LGT SNOW TUE NIGHT.
SLIGHTLY BETTER CHANCE OF LGT SNOW OR FLURRIES ON WED...ESPECIALLY
NEAR WI BORDER WEST AND OVER THE EAST WITH GREATER SATURATION AND A
BIT STRONGER LIFT. POPS MOST AREAS BLO 20 PCT THOUGH.
ANOTHER SHORTWAVE AND SFC TROUGH MAY MOVE THROUGH WED NIGHT INTO
THU. BLEND OF MODELS SUGGEST GREATER CHANCE OF SNOW INTO THU WOULD BE
OVER LK SUPERIOR CLOSER TO TRACK OF SHORTWAVE TROUGH AND WEAK WAVE OF
LOW PRESSURE. ONSHORE FLOW DEVELOPS BEHIND THE TROUGH THU NIGHT INTO
FRI. H85 TEMPS MARGINALLY COOL FOR LAKE EFFECT AT -14C/-15C...BUT
HAVE SOME SMALL CHANCE POPS.
HEIGHTS ALOFT THEN RISE MORE SUBSTANTIALLY THIS WEEKEND. SFC RIDGE
PASSES ACROSS FRI AFTN/FRI NIGHT...SWITCHING WINDS TO SW AND BRINGING
WARMER AIR OVER UPPER GREAT LAKES BY SAT IN RETURN FLOW. DECENT
AGREEMENT ON DEGREE OF WARMING WITH H85 TEMPS WARMING TO AN AVERAGE
OF -6C BY SAT...COOLEST ON THE GFS. WITH THE WARM AIR ADVECTION WILL
COME A STIFF/GUSTY SW WIND IN TIGHTENING PRESSURE GRADIENT BTWN THE
EXITING RIDGE AND TROUGH CROSSING SCNTRL CANADA. CURRENTLY HAVE WINDS
IN THE 10-20 MPH RANGE FOR SAT OVER LAND BUT THAT MAY BUMP HIGHER IF
EXPECTED MSLP PATTERN HOLDS. GOOD DEAL OF MID-HIGH CLOUDS FOR SAT AND
WARM AIR ADVECTION MAY RESULT IN WIDESPREAD LIGHT SNOW ESPECIALLY
SAT AFTN INTO SAT NIGHT. GFS AND GEM MORE IN FAVOR THAN THE ECMWF SO
JUST RAN WITH SLIGHT CHANCE POPS OF CONSENSUS ATTM. ADDITIONAL LIGHT
SNOW OR SNOW SHOWERS COULD OCCUR SAT NIGHT INTO SUN. MAY SEE HIGHS
HEADING BACK ABOVE NORMAL FOR NEXT WEEKEND WITH READINGS REACHING UPR
20S/LOWER 30S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 353 AM EST MON JAN 18 2016
AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT.
EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY
MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH
THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION.
AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST
PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST
WITH NORTHWEST WINDS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 623 PM EST SUN JAN 17 2016
A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR INTO EARLY
TUESDAY...KEEPING WIND GUSTS BETWEEN 25-30KTS WITH HIGHER GALE FORCE
GUSTS TO 35 KNOTS POSSIBLE OVER EASTERN LAKE SUPERIOR LATE THIS
AFTERNOON INTO TONIGHT. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED TODAY INTO MONDAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH
TOWARDS THE MIDDLE OF NEXT WEEK...AS HIGH PRESSURE MOVES OVER THE
UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002-
003-006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-
014-084.
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
LSZ263>267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
354 AM EST MON JAN 18 2016
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 408 PM EST SUN JAN 17 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW
JUST TO THE EAST OF LAKE SUPERIOR. AT THE SFC...NW LOW LEVEL FLOW
PREVAILED BTWN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY
TO SRN ONTARIO. RADAR AND VIS LOOP SHOWED MAINLY MULTI-BAND LES WITH
FEW DOMINANT OR COHERENT BANDSAS THE LES INTENSITY HAS DIMINISHED
SLIGHTLY WITH THE VERY DRY ARCTIC AIR UPSTREAM AND THE LAKES
AGGREGATE TROUGH SHIFTING TO THE SOUTH OF UPPER MICHIGAN.
INSTABILITIY OVER THE LAKE REMAINED HIGH WITH 850/700 MB TEMPS
AROUND -23C/-30C RESULTING IN LAKE INDUCED CAPES NEAR 1K J/KG AND
EQUILLIBRIUM HEIGHTS TO 14K FT.
TONIGHT...EXPECT MODERATE TO OCASSIONALLY HEAV LES TO CONTINUE FOR
NW FLOW FAVORED LOCATIONS. THE HIGH RES MODELS SUGGEST THAT THE MOST
FAVORALBE LOW LEVEL CONV OVER THE WEST WILL FOCUS INTO ONTONAGAON
COUNTY THIS EVENING. OVER THE EAST...MORE DOMINANT BANDS COULD OVER
A WIDER AREA FROM FROM ALGER COUNTY INTO LUCE COUNTY. LES INTENSITY
SHOULD ALSO INCREASE WITH A SHRTWV OVER NRN ONTARIO ROTATING TO NEAR
ERN LAKE SUPERIOR BY 12Z. HOWEVER...WINDS WILL ALSO BACK SLIGHTLY IN
RESPONSE TO THE INCOMING SHRTWV. ALTHOUGH SNOWFALL AMOUNTS MAY NOT
BE AS HEAVY AS LAST NIGHT...5 TO 9 INCH AMOUNTS WILL BE POSSIBLE
OVER THE EAST. THE SHORTER FETCH AND SLIGHTLY LOWER INVERSION
HEIGHTS OVER THE WEST SHOULD KEEP AMOUNTS IN THE 2 TO 5 INCH RANGE.
ENOUGH OF THE CONVECTIVE LAYER WILL REACH INTO THE DGZ TO KEEP SLR
VALUES AOA 25/1.
THE VERY COLD AIR MOVING INTO INTERIOR LOCATIONS WILL DROP WIND
CHILLS INTO THE -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO
CRYSTAL FALLS TONIGHT WHERE A WIND CHILL ADVY REMAINS IN EFFECT.
EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY
IN THE -10 TO -20 RANGE.
MONDAY...AS THE SHRTWV MOVES IN WITH THE STRONGER FORCING SHIFTING
TO THE SOUTH...WINDS WILL GRADUALY VEER. CONDITIONS WILL REMAIN
FAVORABLE FOR MODERATE TO HEAVY LES...AGAIN HEAVIEST OVER THE EAST
WITH SLIGHTLY HIGHER INVERSION HEIGHTS AND LONGER FETCH LENGTHS.
WARNINGS AND ADVISORIES WILL REMAIN IN EFFECT THROUGH THE DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 623 PM EST SUN JAN 17 2016
LES WILL DIMINISH MON NIGHT AND TUE AS 850MB TEMPS INCREASE FROM
AROUND -22C AT 00Z TUE TO AROUND -12C BY 18Z TUE WHILE UPPER AND SFC
RIDGING MOVES IN. STILL HAVE TO RESOLVE SOME MESOSCALE FEATURES THAT
MAY LEAD TO BANDS OF MODERATE TO HEAVY SNOW INTO EARLY TUE
MORNING...BUT THE COVERAGE OF HEAVIER SNOW POTENTIAL WILL REDUCE
INTO THE MORNING...LOOKS LIKE IT WILL BE CONFINED TO ALGER AND NRN
SCHOOLCRAFT COUNTIES. BY THE END OF THE DAY TUE WINDS MAY SWITCH OUT
OF THE W-SW BEHIND THE RIDGE AND AHEAD OF A SHORTWAVE. EXPECT ONLY
VERY MINOR SNOWFALL BY THE END OF THE DAY. POSSIBILITY OF A FEW
INCHES MON NIGHT INTO TUE (MAINLY BEFORE NOON TUE) OVER THE ERN NW
WIND FAVORED ZONES AND JUST A COUPLE INCHES OVER THE NWRN AREAS.
MODELS SHOW A SHORTWAVE MOVING THROUGH THE REGION TUE NIGHT INTO
WED...BUT THE TREND IS FOR MODELS TO SHIFT THAT S...WHICH IS ALSO
THE CONSENSUS. WINDS OVER THE LAKES LOOK DISORGANIZED AND 850MB
TEMPS AROUND -14C...SO ANY LAKE EFFECT WILL BE INSIGNIFICANT. MAY
SEE ANOTHER WEAK SHORTWAVE MOVE THROUGH THE AREA WED NIGHT OR
THU...BUT MODELS SHOW LITTLE TO NO QPF WITH THAT. SHOULD SEE LAKE
ENHANCEMENT...POSSIBLE OVER THE KEWEENAW AND FAR NE DEPENDING ON
WIND DIRECTIONS. NOT LOOKING AT SIGNIFICANT AMOUNTS WITH THIS
SHORTWAVE EITHER.
TREND AFTER THAT CONTINUES TO LOOK DRY AND WARMER. COULD SEE HIGHS
AROUND 30 IN SOME SPOTS ON SAT...THEN A BIT COOLER ON SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 353 AM EST MON JAN 18 2016
AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT.
EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY
MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH
THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION.
AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST
PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST
WITH NORTHWEST WINDS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 623 PM EST SUN JAN 17 2016
A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR INTO EARLY
TUESDAY...KEEPING WIND GUSTS BETWEEN 25-30KTS WITH HIGHER GALE FORCE
GUSTS TO 35 KNOTS POSSIBLE OVER EASTERN LAKE SUPERIOR LATE THIS
AFTERNOON INTO TONIGHT. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED TODAY INTO MONDAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH
TOWARDS THE MIDDLE OF NEXT WEEK...AS HIGH PRESSURE MOVES OVER THE
UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ002-
003-006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-
014-084.
WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MIZ009-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
LSZ263>267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ265-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1157 PM EST SUN JAN 17 2016
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 408 PM EST SUN JAN 17 2016
WV IMAGERY AND RAP ANALYSIS INDICATED A COLD MID/UPPER LEVEL LOW
JUST TO THE EAST OF LAKE SUPERIOR. AT THE SFC...NW LOW LEVEL FLOW
PREVAILED BTWN A RIDGE OVER THE PLAINS AND A TROUGH FROM JAMES BAY
TO SRN ONTARIO. RADAR AND VIS LOOP SHOWED MAINLY MULTI-BAND LES WITH
FEW DOMINANT OR COHERENT BANDSAS THE LES INTENSITY HAS DIMINISHED
SLIGHTLY WITH THE VERY DRY ARCTIC AIR UPSTREAM AND THE LAKES
AGGREGATE TROUGH SHIFTING TO THE SOUTH OF UPPER MICHIGAN.
INSTABILITIY OVER THE LAKE REMAINED HIGH WITH 850/700 MB TEMPS
AROUND -23C/-30C RESULTING IN LAKE INDUCED CAPES NEAR 1K J/KG AND
EQUILLIBRIUM HEIGHTS TO 14K FT.
TONIGHT...EXPECT MODERATE TO OCASSIONALLY HEAV LES TO CONTINUE FOR
NW FLOW FAVORED LOCATIONS. THE HIGH RES MODELS SUGGEST THAT THE MOST
FAVORALBE LOW LEVEL CONV OVER THE WEST WILL FOCUS INTO ONTONAGAON
COUNTY THIS EVENING. OVER THE EAST...MORE DOMINANT BANDS COULD OVER
A WIDER AREA FROM FROM ALGER COUNTY INTO LUCE COUNTY. LES INTENSITY
SHOULD ALSO INCREASE WITH A SHRTWV OVER NRN ONTARIO ROTATING TO NEAR
ERN LAKE SUPERIOR BY 12Z. HOWEVER...WINDS WILL ALSO BACK SLIGHTLY IN
RESPONSE TO THE INCOMING SHRTWV. ALTHOUGH SNOWFALL AMOUNTS MAY NOT
BE AS HEAVY AS LAST NIGHT...5 TO 9 INCH AMOUNTS WILL BE POSSIBLE
OVER THE EAST. THE SHORTER FETCH AND SLIGHTLY LOWER INVERSION
HEIGHTS OVER THE WEST SHOULD KEEP AMOUNTS IN THE 2 TO 5 INCH RANGE.
ENOUGH OF THE CONVECTIVE LAYER WILL REACH INTO THE DGZ TO KEEP SLR
VALUES AOA 25/1.
THE VERY COLD AIR MOVING INTO INTERIOR LOCATIONS WILL DROP WIND
CHILLS INTO THE -20 TO -30 RANGE NEAR THE WI BORDER FROM IRONWOOD TO
CRYSTAL FALLS TONIGHT WHERE A WIND CHILL ADVY REMAINS IN EFFECT.
EXPECT ENOUGH LAKE MODERATION FARTHER NORTH FOR WIND CHILLS MAINLY
IN THE -10 TO -20 RANGE.
MONDAY...AS THE SHRTWV MOVES IN WITH THE STRONGER FORCING SHIFTING
TO THE SOUTH...WINDS WILL GRADUALY VEER. CONDITIONS WILL REMAIN
FAVORABLE FOR MODERATE TO HEAVY LES...AGAIN HEAVIEST OVER THE EAST
WITH SLIGHTLY HIGHER INVERSION HEIGHTS AND LONGER FETCH LENGTHS.
WARNINGS AND ADVISORIES WILL REMAIN IN EFFECT THROUGH THE DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 623 PM EST SUN JAN 17 2016
LES WILL DIMINISH MON NIGHT AND TUE AS 850MB TEMPS INCREASE FROM
AROUND -22C AT 00Z TUE TO AROUND -12C BY 18Z TUE WHILE UPPER AND SFC
RIDGING MOVES IN. STILL HAVE TO RESOLVE SOME MESOSCALE FEATURES THAT
MAY LEAD TO BANDS OF MODERATE TO HEAVY SNOW INTO EARLY TUE
MORNING...BUT THE COVERAGE OF HEAVIER SNOW POTENTIAL WILL REDUCE
INTO THE MORNING...LOOKS LIKE IT WILL BE CONFINED TO ALGER AND NRN
SCHOOLCRAFT COUNTIES. BY THE END OF THE DAY TUE WINDS MAY SWITCH OUT
OF THE W-SW BEHIND THE RIDGE AND AHEAD OF A SHORTWAVE. EXPECT ONLY
VERY MINOR SNOWFALL BY THE END OF THE DAY. POSSIBILITY OF A FEW
INCHES MON NIGHT INTO TUE (MAINLY BEFORE NOON TUE) OVER THE ERN NW
WIND FAVORED ZONES AND JUST A COUPLE INCHES OVER THE NWRN AREAS.
MODELS SHOW A SHORTWAVE MOVING THROUGH THE REGION TUE NIGHT INTO
WED...BUT THE TREND IS FOR MODELS TO SHIFT THAT S...WHICH IS ALSO
THE CONSENSUS. WINDS OVER THE LAKES LOOK DISORGANIZED AND 850MB
TEMPS AROUND -14C...SO ANY LAKE EFFECT WILL BE INSIGNIFICANT. MAY
SEE ANOTHER WEAK SHORTWAVE MOVE THROUGH THE AREA WED NIGHT OR
THU...BUT MODELS SHOW LITTLE TO NO QPF WITH THAT. SHOULD SEE LAKE
ENHANCEMENT...POSSIBLE OVER THE KEWEENAW AND FAR NE DEPENDING ON
WIND DIRECTIONS. NOT LOOKING AT SIGNIFICANT AMOUNTS WITH THIS
SHORTWAVE EITHER.
TREND AFTER THAT CONTINUES TO LOOK DRY AND WARMER. COULD SEE HIGHS
AROUND 30 IN SOME SPOTS ON SAT...THEN A BIT COOLER ON SUN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1157 PM EST SUN JAN 17 2016
AT KIWD/KCMX...NW FLOW LAKE EFFECT CONTINUES INTO MONDAY NIGHT.
EXPECT IFR VSBY DURING THE HEAVIER SNOW BANDS AT IWD...BUT WILL STAY
MVFR FOR THE MOST PART. IFR/LIFR VSBY AT CMX WILL CONTINUE THROUGH
THIS FORECAST PERIOD AND THIS WILL BE A VARIABLE CONDITION.
AT KSAW...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE FORECAST
PERIOD WITH THE LAKE EFFECT SNOW SHOWERS STAYING MOSTLY TO THE EAST
WITH NORTHWEST WINDS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 623 PM EST SUN JAN 17 2016
A TIGHT GRADIENT WILL REMAIN ACROSS LAKE SUPERIOR INTO EARLY
TUESDAY...KEEPING WIND GUSTS BETWEEN 25-30KTS WITH HIGHER GALE FORCE
GUSTS TO 35 KNOTS POSSIBLE OVER EASTERN LAKE SUPERIOR LATE THIS
AFTERNOON INTO TONIGHT. IN ADDITION...HEAVY FREEZING SPRAY IS
EXPECTED TODAY INTO MONDAY. WINDS ARE EXPECTED TO SLOWLY DIMINISH
TOWARDS THE MIDDLE OF NEXT WEEK...AS HIGH PRESSURE MOVES OVER THE
UPPER GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST MONDAY FOR MIZ002-003-
006-007-085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST MONDAY FOR MIZ001-014-
084.
WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR MIZ009-010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST MONDAY FOR
LSZ263>267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
908 PM CST TUE JAN 19 2016
.SYNOPSIS...
ISSUED AT 325 PM CST TUE JAN 19 2016
H5 ANALYSIS THIS MORNING HAD A SHORTWAVE TROUGH EXTENDING
FROM THE DAKOTAS INTO WESTERN NEBRASKA AND SRN COLORADO. UPSTREAM OF
THE TROUGH...A LOW AMPLITUDE RIDGE EXTENDED FROM SWRN UTAH...NWD
INTO SRN ALBERTA. WEST OF THE RIDGE...A SHORTWAVE TROUGH WAS PRESENT
OFF THE COAST WASHINGTON STATE...OREGON AND NORTHERN CALIFORNIA.
CURRENT WV IMAGERY...HAS THE SHORTWAVE EXTENDING FROM EASTERN SOUTH
DAKOTA...INTO SOUTH CENTRAL NEBRASKA. FURTHER WEST...A BROAD PLUME
OF PACIFIC MOISTURE WAS NOTED AND EXTENDED FROM CALIFORNIA...EWD
INTO THE INTER MOUNTAIN WEST. A SECONDARY FEED OF MOISTURE EXTENDED
FROM BAJA CALIFORNIA INTO TEXAS AND THE OZARKS. AT THE
SURFACE...LIGHT SNOW IN ASSOCIATION WITH THE SHORTWAVE TROUGH...HAD
EXITED THE FORECAST AREA BY LATE MORNING. SNOW AMOUNTS WERE ON THE
ORDER OF 1 TO 2 INCHES ACROSS THE EASTERN HALF OF THE FORECAST
AREA...WITH SOME LOCALLY HEAVIER AMOUNTS UP TO 3 INCHES IN CUSTER
COUNTY. SEE OMAPNSLBF FOR DETAILS. SKIES WERE GENERALLY CLOUDY THIS
AFTERNOON WITH THE EXCEPTION OF LOCATIONS ALONG AND WEST OF HIGHWAY
61 FROM MERRIMAN TO IMPERIAL. TEMPERATURES THIS AFTERNOON WERE
GENERALLY IN THE 20S TO LOWER 30S.
&&
.UPDATE...
ISSUED AT 908 PM CST TUE JAN 19 2016
BINGO...DENSE FOG HAS FROMED ACROSS NRN NEB. THE RAP MODEL SHOWS
THIS FOG MOVING EAST OVERNIGHT AND LASTING 3 TO 6 HOURS. IT IS
POSSIBLE IT COULD FORM FARTHER SOUTH ACCORDING TO THIS MODEL BUT
THAT REMAINS UNCERTAIN AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 325 PM CST TUE JAN 19 2016
CLEARING CONTINUES TO SPREAD FROM WEST TO EAST ACROSS THE AREA THIS
EVENING. HOWEVER THE DRY AIR ALOFT AND GOOD RADIATIONAL COOLING WILL
QUICKLY COOL THE SFC TO THE DEW POINT. BOTH THE SHREF AND NAM ARE
SUGGESTING SOME FOG TO DEVELOP...AND WITH THE MELTING OF SOME OF THE
LIGHT SNOW FROM THIS MORNING ADDING TO THE BL MOISTURE AND NEAR CALM
WINDS...GROWING CONFIDENCE THIS COULD DEVELOP. UNSURE ON HOW DENSE
IT WILL GET SO NO HEADLINE BUT WILL NEED TO MONITOR THIS CLOSELY.
LOWS WILL BE MILD FOR MID JANUARY IN THE TEENS TO AROUND 20.
TOMORROW THE FOG WILL SLOWLY ERODE AS THE NEXT WAVE EJECTS ONTO THE
PLAINS. MOISTURE IS ON THE INCREASE...HOWEVER A DRY MID LEVEL WILL
HAVE TO BE OVERCOME BEFORE ANYTHING REACHES THE GROUND...THUS EXPECT
THE DAYTIME TO BE DRY. WEAK RIDGING AHEAD OF THE WAVE WILL PUSH SOME
WARM AIR BRIEFLY INTO THE REGION WHICH SHOULD HELP PUSH EARLY HIGHS
INTO THE MID 30S TO LOWER 40S...WARMEST WERE LITTLE TO NO SNOW PACK.
IF CLOUDS THICKEN QUICKLY...HIGHS COULD BE TO OPTIMISTIC.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 325 PM CST TUE JAN 19 2016
MID RANGE...WEDNESDAY NIGHT THROUGH FRIDAY...THE MAIN FORECAST
CHALLENGE IN THE MID RANGE IS SNOWFALL POTENTIAL WITH A SHORTWAVE
SYSTEM PROGGED TO CROSS THE CENTRAL AND SRN PLAINS WEDS NIGHT INTO
THURSDAY. BEGINNING LATE WEDNESDAY AFTERNOON...WITH THE APPROACH OF
AN UPPER LEVEL JET STREAK...A SHORTWAVE TROUGH...WILL DEEPEN AS IT
TRACKS FROM WYOMING INTO KANSAS. LIFT WILL BEGIN TO INCREASE
OVERNIGHT WEDNESDAY NIGHT...NORTH OF THE SHORTWAVE...WHICH CLOSES
OFF AT BOTH THE H7 AND H5 LEVELS AFTER 06Z THURSDAY. CROSS SECTIONS
TAKEN ACROSS THE EASTERN CWA INDICATE PLENTY OF DENDRITIC ZONE
MOISTURE...ALONG WITH A 12 HR PERIOD (06Z-18Z THURSDAY) OF FAVORABLE
LIFT. THIS AREA OF LIFT IS COLLOCATED WITH AN INVERTED SURFACE TROUGH
OF LOW PRESSURE WHICH IS PRESENT ACROSS THE EASTERN CWA...OR MAINLY
ALONG THE HIGHWAY 183 CORRIDOR FROM ANSLEY TO SPRINGVIEW. SREF QPF/S
AS WELL AS THE OPERATIONAL GFS AND NAM SOLNS INDICATE 10 TO 20
HUNDREDTHS OF AN INCH ALONG THIS CORRIDOR...WHICH BASED ON COBB
RATIOS OF 12 TO 1...YIELDS 1 TO 2 INCHES OF SNOW IN THE EASTERN HALF
OF THE CWA. BASED ON THE CROSS SECTIONS...THIS WILL BE A FAIRLY LONG
(12 HRS)...LIGHT INTENSITY EVENT. ATTM FEEL FAIRLY CONFIDENT IN
QPF/S AND ACCUMS...HOWEVER...LAYER PWATS IN THE NAM SOLN ARE RUNNING
A QUARTER TO BRIEFLY A HALF AN INCH DURING THE PERIOD AND THIS IS
CONCERNING. IF THIS VERIFIES...WE COULD BE LOOKING AT MORE SNOW
ACCUMS THAN CURRENT THINKING. WILL CONTINUE TO MONITOR THIS WITH THE
NEXT COUPLE OF FCST CYCLES. PROGRESSING INTO THURSDAY
AFTERNOON...THE UPPER LEVEL LOW WILL TRACK SOUTHEAST INTO THE
OZARKS...AS A RIDGE BEGINS TO BUILD INTO THE INTER MOUNTAIN WEST.
LIFT WILL BEGIN TO WEAKEN QUICKLY BY THURSDAY AFTERNOON IN THE
EAST...WHILE HIGH PRESSURE BUILDS SOUTH FROM THE EASTERN DAKOTAS.
SUBSIDENCE AND DRIER AIR...WILL BRING THE THREAT FOR SNOW TO AN END
DURING THE AFTERNOON HOURS. ON THURSDAY NIGHT...HIGH PRESSURE WILL
BUILD SOUTH INTO EASTERN NEBRASKA. LOW TEMPERATURES WERE TRENDED
DOWNWARD IN THE EAST GIVEN ITS PROXIMITY TO THE TRACK OF THE HIGH
WITH GUIDANCE UNDERCUT 2 TO 5 DEGREES. HIGH PRESSURE WILL TRANSITION
EAST INTO MINNESOTA AND NORTHERN IOWA BY FRIDAY AFTERNOON. WARMER
AIR WILL BEGIN TO PUSH INTO WESTERN NEBRASKA BY AFTERNOON...WITH H85
TEMPS REACHING ABOVE 0C WEST OF HIGHWAY 61. WINDS...ESPECIALLY EAST
OF HIGHWAY 61 WILL BE LIGHT...SO NOT MUCH MIXING WILL TAKE PLACE.
THIS WILL RESULT IN SUB FREEZING HIGHS GENERALLY EAST OF HIGHWAY
83...WHILE LOCATIONS WEST OF THIS ROUTE MAY REACH THE MID 30S TO
LOWER 40S IN THE EASTERN PANHANDLE.
LONG RANGE...FRIDAY NIGHT THROUGH TUESDAY...BEGINNING FRIDAY
NIGHT...RIDGING WILL BUILD EAST OF THE ROCKIES ONTO THE CENTRAL
PLAINS. MUCH WARMER H85 AIR WILL PUSH EAST WITH H85 TEMPS SAT
AFTERNOON OF 4 TO 8C. INHERITED FCST OF 40S TO LOWER 50S SATURDAY
ARE ON TRACK. A PACIFIC COOL FRONT WILL PUSH INTO THE FORECAST
AREA SUNDAY AFTERNOON. HIGHS WILL FALL BACK TO MORE SEASONAL
LEVELS SUNDAY...MONDAY AND TUESDAY. WITH THE FRONTAL
PASSAGE...THERE WILL BE A SMALL THREAT FOR RAIN OR SNOW SHOWERS
SUNDAY...FOLLOWED BY A SLIGHT CHANCE FOR SNOW ON SUNDAY NIGHT.
BEYOND TUESDAY...THE LATEST ECMWF AND GFS SOLNS DEVELOP A ZONAL
FLOW PATTERN NEXT WEEK WITH ARCTIC AIR WELL NORTH OF THE CWA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 534 PM CST TUE JAN 19 2016
THE GENERAL CONSENSUS OF THE RAP...HRRR AND NAM MODELS SUGGESTS A
BANK OF FOG WILL FORM ON THE WRN FLANK OF THE STRATUS CURRENTLY IN
PLACE ACROSS NCNTL NEB. THE FOG LOCATION COULD BE SOMEWHAT WEST
OF HIGHWAY 83. WE WILL HAVE TO WAIT FOR IT TO FORM TO GET A FIX ON
THE LOCATION.
OTHERWISE...A LOW LEVEL JET FORMS TONIGHT WEST OF THE FOG BANK
ALONG HIGHWAY 61 ANGLED TOWARD VALENTINE. THIS SHOULD SCOUR
MOISTURE FROM THE SANDHILLS AND LEAVE A POOL OF TRAPPED MOISTURE
OVER KLBF WEDNESDAY. GIVEN THAT...IFR/MVFR CIGS COULD BE LOCKED IN
ALL DAY OVER KLBF.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST /8 AM MST/ WEDNESDAY FOR
NEZ005>010.
&&
$$
UPDATE...CDC
SYNOPSIS...BUTTLER
SHORT TERM...MASEK
LONG TERM...BUTTLER
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
533 PM CST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 336 PM CST TUE JAN 19 2016
MAIN CONCERN IS FOG POTENTIAL TONIGHT. GENERAL SYNOPTIC PATTERN IS
QUITE PROGRESSIVE AS WE TRANSITION TO A HIGHER AMPLITUDE SCENARIO.
TONIGHT...THE CONCERN GOES TO FOG POTENTIAL TONIGHT AS WIND WILL BE
LIGHT FROM THE SOUTH. THE HRRR IS HITTING THE FOG POTENTIAL A LITTLE
HARD CENTRAL AND WEST. THE SREF IS ALSO HITTING FOG A LITTLE HARD
EVERYWHERE ACROSS THE CWA...ESPECIALLY WEST. I WENT WITH STRONG
WORDING IN THE FORECAST TO AREAS RATHER THAN PATCHY AND EXTENDED THE
FOG MENTION FARTHER EAST THAN THE PREVIOUS FORECAST.
WE MAY SEE A LITTLE SUN WEDNESDAY MORNING BEFORE IT CLOUDS BACK UP
IN ADVANCE OF THE NEXT WAVE QUICKLY APPROACHING. WARM AIR ADVECTION
SHOULD BOOST TEMPERATURES A GOOD 10 DEGREES WARMER ON WEDNESDAY
COMPARED TO TODAY. NOT EXPECTING PRECIP UNTIL PERHAPS BETWEEN 21Z
AND 00Z THURSDAY IN OUR FAR SOUTH...WHERE RAIN/SNOW COULD
OCCUR...BUT THE BETTER CHANCES WILL LIKELY BE TOWARD WEDNESDAY
NIGHT...IN THE LONG TERM FORECAST.
SUPERBLEND TEMPERATURES LOOKED REASONABLE...WHICH LOWERED
TEMPERATURES A BIT FOR WEDNESDAY HIGHS COMPARED TO THE PREVIOUS
FORECAST. THIS SEEMS REASONABLE CONSIDERING LINGERING FOG POTENTIAL
AND INCREASING SKY COVER BY AFTERNOON. BCONSRAW AND NAM12 SOLUTIONS
INDICATE THAT IT MIGHT EVEN BE A BIT COOLER THAN THE MID 30S I HAVE
ADVERTISED IN THE FORECAST....WITH COOLER TEMPERATURES EAST AND
WARMER WEST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 336 PM CST TUE JAN 19 2016
ALOFT: VERY LITTLE CHANGE IN THE PATTERN IS ENVISIONED FOR AT LEAST
THE NEXT WEEK. A MEAN TROF WILL REMAIN OVER THE E PAC WITH THE MEAN
RIDGE OVER WRN N AMERICA. THE FLOW WILL INITIALLY BE MODERATELY
AMPLIFIED BUT WILL DEAMPLIFY TEMPORARILY AS A TROF MOWS DOWN THE
RIDGE FRI-SAT AND EMERGES INTO THE PLAINS SUN-MON. NW FLOW WILL
FOLLOW TUE.
AT 00Z/THU A SHORTWAVE TROF WILL BE MOVING IN AND AMPLIFYING...WITH
A MID-LVL CIRCULATION CLOSING OFF OVER NEB/KS BY 06Z. THIS LOW WILL
DROP SSE THU WITH QUIETER WX TO FOLLOW.
SURFACE: A WEAK COLD FRONT WILL MOVE THRU WED NIGHT. LEE
CYCLOGENESIS WILL BE UNDERWAY WED EVE WITH THE SFC LOW FAR TO THE S
OVER TX. CANADIAN HIGH PRES WILL GRADUALLY BUILD IN THU-FRI. RETURN
FLOW DEVELOPS SAT AS A CLIPPER HEADS E ACROSS SRN CANADA. A NICE
DOWNSLOPE-WARMED AIR MASS WILL OVERTAKE THE REGION...BUT SNOW ON THE
GROUND WILL TEMPER THE WARM-UP. THE NEXT PAC COOL FRONT WILL BE
MAKING ITS WAY THRU THE WRN USA AND WILL ARRIVE HERE LATE SUN. HIGH
PRES WILL MOVE IN MON AND DROP INTO THE SRN PLAINS TUE.
SOME DAILY DETAILS...
WED NIGHT: SNOW WILL BE BLOSSOMING OVER N-CNTRL KS AND EXPANDING N
INTO S-CNTRL NEB.
THU: A SWATH OF SNOW WILL PROBABLY STILL ENCOMPASS MUCH OF THE FCST
AREA THRU THE MORNING...RESULTING IN PERIODS OF SNOW. IT WILL
DIMINISH AND END IN THE AFTERNOON.
CURRENT EXPECTATION IS THAT MOST IF NOT ALL THE ACCUMULATING SNOW
WILL FALL WED NIGHT. WHILE SNOW WILL CONT INTO THU THE LIFT WILL NOT
BE ENOUGH TO RESULT IN MUCH ACCUM.
SNOW RATIOS: THIS IS TOUGH BECAUSE THE MESOSCALE NATURE OF THIS
SYSTEM WILL RESULT IN HIGHLY NON-UNIFORM LIFT. HIGHER UPWARD
VERTICAL MOTION (UVM) WILL RESULT IN HIGHER RATIOS WITHIN THE BAND.
GIVEN THAT THE BAND SHOULD BE TRANSIENT...KEPT RATIOS IN THE 10-12
RANGE.
BASED ON NAM SOUNDINGS...UVM WILL BE FAIRLY GOOD BELOW THE DGZ FROM
I-80 SOUTH. WITH TEMPS WARMER THAN -5C...THIS WILL RESULT IN
SUBSTANTIAL RIMING AND RATIOS CLOSE TO 10:1...IE A WETTER SNOW. N OF
I-80...IF THE NAM IS CORRECT UVM WILL BE WEAK RESULTING IN LESSER
QUALITY/SMALLER FLAKES. THAT TOO SUPPORTS A LOWER RATIO OF 10 OR
LESS.
ACCUMS: THESE RATIOS OFFER 1-2" AND THAT IS THE OFFICIAL FCST AT
THIS POINT...WITH 3-4" POSSIBLE IN A SMALLER AREA WHERE THE BAND IS
MORE PERSISTENT. WE JUST DON`T KNOW WHERE THAT WILL OCCUR.
SNOW ALGORITHMS FROM THE 06Z/12Z 20KM GFS AND 12Z/18Z NAM OFFER 2-4"
ACROSS MUCH OF THE FCST AREA...WITH ISOLATED 6" AMTS POSSIBLE.
THE EC CONTS TO BE ON THE HEAVY SIDE OF THE GUIDANCE DISTRIBUTION
CONSISTENTLY DUMPING ABOUT .50" SOMEWHERE NEAR ROOKS/OSBORNE/
MITCHELL COUNTIES. THAT INCLUDES THE LAST 4 RUNS. HOWEVER...THE 12Z
EC ENSEMBLE MEAN PROBABILITY FOR .50" IN 24 HRS 10% OR LESS. SO THAT
CONSTRAINS ME FROM GETTING OVERLY EXCITED.
WINDS WILL NOT BE A FACTOR WITH THIS EVENT.
FRI: DECREASING CLOUDS AS SUBSIDENT NW FLOW MOVES IN. HIGH TEMPS
PROBABLY COLDER THAN NORMAL.
SAT: TEMPS AT LEAST NORMAL IF NOT ABOVE. SNOW ON THE GROUND IS A
HUGE MITIGATING FACTOR. OTHERWISE...WIDESPREAD HIGHS IN THE 40S AND
50S WOULD BE ON THE TABLE.
SUN-MON: INCREASING CLOUDS. COOLER. POSSIBLY A TOUGH OF LIGHT
PRECIP AS THE FRONT/TROF MOVE IN.
&&
.AVIATION...(FOR THE 00Z KGRI/KEAR TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 533 PM CST TUE JAN 19 2016
THE MAIN AVIATION FORECAST CONCERN IS THE DEVELOPMENT OF FOG
OVERNIGHT. WINDS WILL BE LIGHT THROUGHOUT THE NIGHT...ALLOWING FOG
TO DEVELOP IN THE MOIST...SNOW COVERED BOUNDARY LAYER. HAVE
TRENDED DOWNWARD FROM THE PREVIOUS FORECAST WITH MVFR CONDITIONS
CONTINUED OVERNIGHT TOWARDS MORNING. THE HRRR IS THE MOST
PESSIMISTIC REGARDING CEILINGS AND VISIBILITIES...OTHER GUIDANCE
IS NOT QUITE THAT RESTRICTIVE AS FAR EAST AS KGRI. IF THE HRRR IS
ACCURATE IFR TO LIFR CONDITIONS COULD BE POSSIBLE TOWARDS MORNING.
WILL BE WATCHING FOR LATER FORECASTS AND AMENDING IF NEEDED FOR
LOWER VISIBILITIES/CEILINGS WITH FOG DEVELOPMENT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...BILLINGS WRIGHT
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
945 AM PST MON JAN 18 2016
.SYNOPSIS...A PROGRESSIVE PACIFIC WEATHER PATTERN WILL DIRECT STORMS
MAINLY ACROSS NORTHERN CALIFORNIA AND NEVADA THIS WEEK.
HOWEVER...CONSIDERABLE CLOUDINESS AND EVEN A CHANCE FOR SOME LIGHT
PRECIPITATION WILL MANAGE TO BRUSH THE SOUTHERN GREAT BASIN AND
PARTS OF THE MOJAVE DESERT MONDAY AND TUESDAY.
&&
.UPDATE...JUST SENT OUT AN UPDATE TO MAKE SOME TWEAKS TO CLOUDS AND
POPS FOR TODAY. MAINLY ADJUSTED CLOUD COVER DOWNWARD ACROSS THE
WESTERN MOJAVE DESERT AND DEATH VALLEY AREA THIS MORNING WHERE A DRY
PUNCH IS CLEARLY PUSHING IN AS NOTED ON SATELLITE IMAGERY. THIS WILL
SPREAD EAST LATER THIS MORNING BREAKING UP THE THICKER CLOUD COVER
ACROSS SOUTHERN NEVADA AS WELL.
MADE ONLY MINOR ADJUSTMENTS TO POPS BUT DO THINK THE SOUTHERN EXTENT
OF PRECIP CHANCES ACROSS THE DESERTS INCLUDING LAS VEGAS IS LOOKING
QUITE LOW. MAINTAINED SLIGHT CHANCE FOR LAS VEGAS AS THE REMAINS OF
THE PACIFIC FRONT MOVE THROUGH BUT ADJUSTED TO SPRINKLES WORDING AND
WOULDNT BE SURPRISED TO SEE NOTHING MATERIALIZE AT ALL.
MEANWHILE...CAMS SHOWING SHOWERS BREAKING OUT ACROSS THE NORTHERN
OWENS VALLEY NEAR BISHOP SO THINGS ARE ON TRACK UP THERE.
STRONGER DRY PUNCH PUSHING IN MAY ALSO TRANSLATE TO BREEZY SOUTHWEST
WINDS LATER THIS AFTERNOON FOR MANY OF THE LOWER DESERT CITIES.
-OUTLER-
&&
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT.
CONSIDERABLE MID AND HIGH-LEVEL MOISTURE HAS OVERSPREAD THE REGION
THIS MORNING AS A WAVE PUSHES INTO THE CENTRAL AND SOUTHERN
CALIFORNIA COAST. SOME ENHANCED SOUTHWEST WINDS ARE EXPECTED TO
DEVELOP THIS MORNING ACROSS THE WESTERN MOJAVE DESERT...MAINLY NEAR
FORT IRWIN AND BARSTOW. WINDS ARE EXPECTED TO MAINLY REMAIN BELOW
ADVISORY CRITERIA...WITH A STRAY GUST IN EXCESS OF 40 MPH NEAR FORT
IRWIN. THIS SYSTEM WILL PUSH A NARROW BAND OF ENHANCED LOW TO MID-
LEVEL MOISTURE ACROSS THE REGION TODAY...WHICH CLOUD RESULT IN A FEW
ISOLATED TO SCATTERED SHOWERS WHEN COMBINED WITH NEARBY WEAK
DYNAMICS. THE BEST CHANCES FOR THESE SHOWERS WILL BE ACROSS THE
SIERRA AND SOUTHERN GREAT BASIN...BUT THE LATEST HRRR RUNS HAVE
SHOWN SOME ACTIVITY A BIT FURTHER SOUTH AND I CANNOT COMPLETELY RULE
OUT A FEW STRAY SHOWERS ALONG THE I-15 CORRIDOR. POPS WERE EXPANDED
AS A RESULT.
ANY SHOWER ACTIVITY SHOULD TAPER OFF THIS EVENING WITH QUIET
CONDITIONS EXPECTED OVERNIGHT. ANOTHER WAVE WILL PUSH ACROSS
NORTHERN CALIFORNIA AND NEVADA TUESDAY AFTERNOON THROUGH TUESDAY
NIGHT...WHICH WILL RESULT IN ANOTHER THIN BAND OF ENHANCED MOISTURE
DIRECTED AT THE REGION. DYNAMICS ASSOCIATED WITH THIS SYSTEM ARE
QUITE A BIT FURTHER NORTH...BUT THE MOISTURE LEVELS ARE HIGHER.
THEREFORE...SIMILAR PRECIPITATION CHANCES CAN BE EXPECTED WITH THIS
SECOND SYSTEM COMPARED TO TODAY.
PRECIPITATION AMOUNTS WITH BOTH SYSTEMS SHOULD BE LIGHT...WITH THE
SIERRA SEEING THE HIGHEST ACCUMULATIONS. IN THE SIERRA...0.2-0.4
INCHES OF LIQUID...OR 3-6 INCHES OF SNOW ABOVE 7000 FEET IS EXPECTED
WITH EACH SYSTEM). ELSEWHERE...AMOUNTS (IF ANY) WOULD BE A TRACE TO
0.1 INCH OF LIQUID.
DRIER CONDITIONS WILL RETURN TO THE REGION WEDNESDAY AS A RIDGE
AMPLIFIES OVER THE WESTERN CONUS. TEMPERATURES ARE EXPECTED TO RUN
NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE SHORT TERM.
.LONG TERM...THURSDAY THROUGH MONDAY.
NOT MUCH CHANGE TO THE LONG TERM FROM THIS TIME YESTERDAY. AMPLIFIED
BUT PROGRESSIVE RIDGING WILL BE IN PLACE THURSDAY IN ADVANCE OF THE
NEXT SYSTEM APPROACHING THE WEST COAST BY 00Z SATURDAY. A FEW TIMING
DISCREPANCIES REMAIN WITH THIS NEXT SYSTEM LARGELY OWING TO THE
DIFFERENCES IN THE AMPLITUDE OF THE RIDGING IN THE INTERIOR WEST
WITH THE ECMWF REMAINING SOMEWHAT STRONGER AND LESS PROGRESSIVE WITH
THE EARLY WEEKEND SYSTEM AND THE 00Z CMC SLOWER STILL. NEVERTHELESS,
MODELS CONTINUE TO SUGGEST NOT MUCH PRECIP EXCEPT FOR FAR NORTHERN
PORTIONS OF THE CWA. TIMING OF ONSET OF PRECIP REMAINS LOW
CONFIDENCE WITH ANYWHERE BETWEEN 12Z-18Z FRIDAY (GFS/ECMWF) AND 06Z
SATURDAY (CMC) DEPICTED. IF THE ONSET OF PRECIP IS FASTER...ABOUT A
24-HOUR PERIOD OF SNOW IS LIKELY NEAR THE SIERRA CREST...WHEREAS THE
CMC PROVIDES A MUCH BRIEFER WINDOW (MORE LIKE 12 HOURS). NOT VERY
CONFIDENT DISCUSSING PRECIP TOTALS GIVEN THESE DISCREPANCIES...BUT
THE MORE AGGRESSIVE SOLUTIONS ARE NOT GENERATING IMPRESSIVE
TOTALS DURING THIS TIME.
PRECIP FOR THE SOUTHERN GREAT BASIN IS MORE UNCERTAIN...WITH MODEL
SOLUTIONS CONTINUING TO DIVERGE DURING THIS TIME. THE CMC PRODUCES
LITTLE IF ANY PRECIP FOR THIS AREA AS THE FIRST OF TWO VORT MAXES
PROGRESSES RAPIDLY EASTWARD INTO ID/UT BY 18Z SATURDAY, STAYING TOO
FAR NORTH TO GENERATE SUFFICIENT LIFT FOR PRECIP IN OUR AREA. THE
GFS PROVIDES FAIRLY DECENT AGREEMENT WITH THIS SCENARIO...THOUGH IT
IS SLIGHTLY FARTHER SOUTH...CLIPPING AT LEAST THE FAR NORTHERN CWA.
THE 00Z ECMWF IS DEEPER WITH THIS TROUGH...ENABLING SCATTERED PRECIP
TO BREAK OUT INTO NORTHERN CLARK AND MOHAVE COUNTIES. THE EURO ALSO
KEEPS THIS PRECIP AROUND LONGER GIVEN THE SLOWER PROGRESSION OF THE
TROUGH...THROUGH 06Z SUNDAY. FOR NOW...BROAD-BRUSHED LOW POPS FOR
THE SOUTHERN GREAT BASIN ON SATURDAY. IF PRECIP DOES OCCUR...AMOUNTS
SHOULD BE LIGHT IN THIS AREA.
MODELS DIVERGE FURTHER INTO THE DAY SUNDAY WITH THE 00Z ECMWF
DEVELOPING AN UPSTREAM VORT MAX RAPIDLY PROGRESSING FROM NORTHWEST
TO SOUTHEAST THROUGH THE AREA BY 00Z MONDAY. THE GFS DEVELOPS A
SIMILAR VORT MAX BUT MUCH FARTHER SOUTH (CLIPPING THE FAR SOUTHERN
PARTS OF THE CWA). MEANWHILE, THE CMC DEVELOPS THIS SYSTEM TO THE
NORTHEAST OF THE AREA. GOOD NEWS IS ALL THREE PRODUCE VERY LIGHT
PRECIP AT MOST WITH THIS VORT MAX. AS SUCH...UNTIL MODELS
CONVERGE...KEPT SILENT TO VERY SLIGHT CHANCE POPS IN FOR THE
DAY SUNDAY.
TEMPERATURES WILL BE SLIGHTLY ABOVE AVERAGE THURSDAY THROUGH
SUNDAY...WITH THE WARMEST TEMPS ON FRIDAY AND THE COOLEST TEMPS ON
SUNDAY FOLLOWING THE PASSAGE OF THE WEAK SYSTEMS MOVING THROUGH THIS
WEEKEND.
THEREAFTER, MODELS DEVELOP A HIGH-AMPLITUDE RIDGE ALONG THE WEST
COAST AND DRY CONDITIONS FOR OUR AREA. THE CHARACTERISTICS OF THIS
RIDGE VARY BASED ON MODEL OF CHOICE, BUT ALL SEEM TO AGREE THAT
STRONG NORTHERLY FLOW DEVELOPS IN OUR AREA MONDAY, SUGGESTING THAT
WINDS MAY BLOW RATHER STRONGLY IN THE COLORADO RIVER VALLEY. PLENTY
OF TIME TO DETERMINE IF THIS COMES TO FRUITION. PERHAPS OF MORE
IMPORTANCE, THE SOLUTIONS ARE TRENDING TOWARD A STRONGER SUBTROPICAL
RIDGE IN THE EAST PACIFIC NEXT WEEK, WHICH DOES NOT BODE WELL FOR
A MORE SOUTHERN STORM TRACK ANY TIME SOON.
&&
.AVIATION...FOR MCCARRAN...MAINLY LIGHT WINDS THROUGH MID-DAY
FOLLOWING TYPICAL DIURNAL TRENDS. CIGS WILL LOWER THROUGH THE
DAY...DROPPING TO AROUND 8K FEET BY THIS EVENING. A STRAY SHOWER
CANNOT BE COMPLETELY RULED OUT DURING THE AFTERNOON. THE WIND
FORECAST BECOMES TRICKY THIS AFTERNOON AS THERE COULD BE A BATTLE
BETWEEN EAST/NORTHEAST WINDS AND GUSTY SOUTHWEST WINDS IN THE
VICINITY OF THE TERMINAL. WITH THE POTENTIAL FOR A SHOWER AND
SIGNIFICANT CLOUD COVER...WITH ERR ON THE SIDE OF LIGHTER
EAST/NORTHEAST WINDS FOR THE 12Z TAF. IN REALITY...WINDS COULD FAVOR
EITHER DIRECTION BETWEEN ROUGHLY 19Z-01Z THIS AFTERNOON. QUIET
WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY...WITH ANOTHER VERY
SLIGHT CHANCE OF SHOWERS TUESDAY EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...INCREASING SOUTHWEST WINDS EXPECTED ACROSS THE WESTERN
MOJAVE DESERT THIS MORNING (MAINLY SOUTH OF A KNID-KDRA-KSGU LINE).
TO THE NORTH...LIGHTER WINDS ARE EXPECTED TO FAVOR TYPICAL DIURNAL
TRENDS IN VALLEY LOCATIONS. IT`S UNCLEAR WHETHER THE SOUTHWEST
WINDS WILL MAKE IT INTO THE LAS VEGAS VALLEY...WITH KHND BEING THE
MOST LIKELY LOCATION IF THEY DO. CIGS ARE EXPECTED TO DROP TO 5-8K
FEET AS A WEAK SYSTEM PASSES THROUGH THE REGION. THIS WILL ALSO
BRING A SLIGHT CHANCE OF SHOWERS TO THE REGION...MAINLY NORTH OF LAS
VEGAS...HOWEVER A FEW STRAY SHOWERS TO THE SOUTH CANNOT BE RULED
OUT. QUIET WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY MORNING...WITH
ANOTHER SLIGHT CHANCE OF SHOWERS ACROSS THE REGION TUESDAY.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED.
PLEASE REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
$$
SHORT TERM/AVIATION...WOLCOTT
LONG TERM.............SHAFER
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
300 AM PST MON JAN 18 2016
.SYNOPSIS...A PROGRESSIVE PACIFIC WEATHER PATTERN WILL DIRECT STORMS
MAINLY ACROSS NORTHERN CALIFORNIA AND NEVADA THIS WEEK.
HOWEVER...CONSIDERABLE CLOUDINESS AND EVEN A CHANCE FOR SOME LIGHT
PRECIPITATION WILL MANAGE TO BRUSH THE SOUTHERN GREAT BASIN AND
PARTS OF THE MOJAVE DESERT MONDAY AND TUESDAY.
&&
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT.
CONSIDERABLE MID AND HIGH-LEVEL MOISTURE HAS OVERSPREAD THE REGION
THIS MORNING AS A WAVE PUSHES INTO THE CENTRAL AND SOUTHERN
CALIFORNIA COAST. SOME ENHANCED SOUTHWEST WINDS ARE EXPECTED TO
DEVELOP THIS MORNING ACROSS THE WESTERN MOJAVE DESERT...MAINLY NEAR
FORT IRWIN AND BARSTOW. WINDS ARE EXPECTED TO MAINLY REMAIN BELOW
ADVISORY CRITERIA...WITH A STRAY GUST IN EXCESS OF 40 MPH NEAR FORT
IRWIN. THIS SYSTEM WILL PUSH A NARROW BAND OF ENHANCED LOW TO MID-
LEVEL MOISTURE ACROSS THE REGION TODAY...WHICH CLOUD RESULT IN A FEW
ISOLATED TO SCATTERED SHOWERS WHEN COMBINED WITH NEARBY WEAK
DYNAMICS. THE BEST CHANCES FOR THESE SHOWERS WILL BE ACROSS THE
SIERRA AND SOUTHERN GREAT BASIN...BUT THE LATEST HRRR RUNS HAVE
SHOWN SOME ACTIVITY A BIT FURTHER SOUTH AND I CANNOT COMPLETELY RULE
OUT A FEW STRAY SHOWERS ALONG THE I-15 CORRIDOR. POPS WERE EXPANDED
AS A RESULT.
ANY SHOWER ACTIVITY SHOULD TAPER OFF THIS EVENING WITH QUIET
CONDITIONS EXPECTED OVERNIGHT. ANOTHER WAVE WILL PUSH ACROSS
NORTHERN CALIFORNIA AND NEVADA TUESDAY AFTERNOON THROUGH TUESDAY
NIGHT...WHICH WILL RESULT IN ANOTHER THIN BAND OF ENHANCED MOISTURE
DIRECTED AT THE REGION. DYNAMICS ASSOCIATED WITH THIS SYSTEM ARE
QUITE A BIT FURTHER NORTH...BUT THE MOISTURE LEVELS ARE HIGHER.
THEREFORE...SIMILAR PRECIPITATION CHANCES CAN BE EXPECTED WITH THIS
SECOND SYSTEM COMPARED TO TODAY.
PRECIPITATION AMOUNTS WITH BOTH SYSTEMS SHOULD BE LIGHT...WITH THE
SIERRA SEEING THE HIGHEST ACCUMULATIONS. IN THE SIERRA...0.2-0.4
INCHES OF LIQUID...OR 3-6 INCHES OF SNOW ABOVE 7000 FEET IS EXPECTED
WITH EACH SYSTEM). ELSEWHERE...AMOUNTS (IF ANY) WOULD BE A TRACE TO
0.1 INCH OF LIQUID.
DRIER CONDITIONS WILL RETURN TO THE REGION WEDNESDAY AS A RIDGE
AMPLIFIES OVER THE WESTERN CONUS. TEMPERATURES ARE EXPECTED TO RUN
NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE SHORT TERM.
.LONG TERM...THURSDAY THROUGH MONDAY.
NOT MUCH CHANGE TO THE LONG TERM FROM THIS TIME YESTERDAY. AMPLIFIED
BUT PROGRESSIVE RIDGING WILL BE IN PLACE THURSDAY IN ADVANCE OF THE
NEXT SYSTEM APPROACHING THE WEST COAST BY 00Z SATURDAY. A FEW TIMING
DISCREPANCIES REMAIN WITH THIS NEXT SYSTEM LARGELY OWING TO THE
DIFFERENCES IN THE AMPLITUDE OF THE RIDGING IN THE INTERIOR WEST
WITH THE ECMWF REMAINING SOMEWHAT STRONGER AND LESS PROGRESSIVE WITH
THE EARLY WEEKEND SYSTEM AND THE 00Z CMC SLOWER STILL. NEVERTHELESS,
MODELS CONTINUE TO SUGGEST NOT MUCH PRECIP EXCEPT FOR FAR NORTHERN
PORTIONS OF THE CWA. TIMING OF ONSET OF PRECIP REMAINS LOW
CONFIDENCE WITH ANYWHERE BETWEEN 12Z-18Z FRIDAY (GFS/ECMWF) AND 06Z
SATURDAY (CMC) DEPICTED. IF THE ONSET OF PRECIP IS FASTER...ABOUT A
24-HOUR PERIOD OF SNOW IS LIKELY NEAR THE SIERRA CREST...WHEREAS THE
CMC PROVIDES A MUCH BRIEFER WINDOW (MORE LIKE 12 HOURS). NOT VERY
CONFIDENT DISCUSSING PRECIP TOTALS GIVEN THESE DISCREPANCIES...BUT
THE MORE AGGRESSIVE SOLUTIONS ARE NOT GENERATING IMPRESSIVE
TOTALS DURING THIS TIME.
PRECIP FOR THE SOUTHERN GREAT BASIN IS MORE UNCERTAIN...WITH MODEL
SOLUTIONS CONTINUING TO DIVERGE DURING THIS TIME. THE CMC PRODUCES
LITTLE IF ANY PRECIP FOR THIS AREA AS THE FIRST OF TWO VORT MAXES
PROGRESSES RAPIDLY EASTWARD INTO ID/UT BY 18Z SATURDAY, STAYING TOO
FAR NORTH TO GENERATE SUFFICIENT LIFT FOR PRECIP IN OUR AREA. THE
GFS PROVIDES FAIRLY DECENT AGREEMENT WITH THIS SCENARIO...THOUGH IT
IS SLIGHTLY FARTHER SOUTH...CLIPPING AT LEAST THE FAR NORTHERN CWA.
THE 00Z ECMWF IS DEEPER WITH THIS TROUGH...ENABLING SCATTERED PRECIP
TO BREAK OUT INTO NORTHERN CLARK AND MOHAVE COUNTIES. THE EURO ALSO
KEEPS THIS PRECIP AROUND LONGER GIVEN THE SLOWER PROGRESSION OF THE
TROUGH...THROUGH 06Z SUNDAY. FOR NOW...BROAD-BRUSHED LOW POPS FOR
THE SOUTHERN GREAT BASIN ON SATURDAY. IF PRECIP DOES OCCUR...AMOUNTS
SHOULD BE LIGHT IN THIS AREA.
MODELS DIVERGE FURTHER INTO THE DAY SUNDAY WITH THE 00Z ECMWF
DEVELOPING AN UPSTREAM VORT MAX RAPIDLY PROGRESSING FROM NORTHWEST
TO SOUTHEAST THROUGH THE AREA BY 00Z MONDAY. THE GFS DEVELOPS A
SIMILAR VORT MAX BUT MUCH FARTHER SOUTH (CLIPPING THE FAR SOUTHERN
PARTS OF THE CWA). MEANWHILE, THE CMC DEVELOPS THIS SYSTEM TO THE
NORTHEAST OF THE AREA. GOOD NEWS IS ALL THREE PRODUCE VERY LIGHT
PRECIP AT MOST WITH THIS VORT MAX. AS SUCH...UNTIL MODELS
CONVERGE...KEPT SILENT TO VERY SLIGHT CHANCE POPS IN FOR THE
DAY SUNDAY.
TEMPERATURES WILL BE SLIGHTLY ABOVE AVERAGE THURSDAY THROUGH
SUNDAY...WITH THE WARMEST TEMPS ON FRIDAY AND THE COOLEST TEMPS ON
SUNDAY FOLLOWING THE PASSAGE OF THE WEAK SYSTEMS MOVING THROUGH THIS
WEEKEND.
THEREAFTER, MODELS DEVELOP A HIGH-AMPLITUDE RIDGE ALONG THE WEST
COAST AND DRY CONDITIONS FOR OUR AREA. THE CHARACTERISTICS OF THIS
RIDGE VARY BASED ON MODEL OF CHOICE, BUT ALL SEEM TO AGREE THAT
STRONG NORTHERLY FLOW DEVELOPS IN OUR AREA MONDAY, SUGGESTING THAT
WINDS MAY BLOW RATHER STRONGLY IN THE COLORADO RIVER VALLEY. PLENTY
OF TIME TO DETERMINE IF THIS COMES TO FRUITION. PERHAPS OF MORE
IMPORTANCE, THE SOLUTIONS ARE TRENDING TOWARD A STRONGER SUBTROPICAL
RIDGE IN THE EAST PACIFIC NEXT WEEK, WHICH DOES NOT BODE WELL FOR
A MORE SOUTHERN STORM TRACK ANY TIME SOON.
&&
.AVIATION...FOR MCCARRAN...MAINLY LIGHT WINDS THROUGH MID-DAY
FOLLOWING TYPICAL DIURNAL TRENDS. CIGS WILL LOWER THROUGH THE
DAY...DROPPING TO AROUND 8K FEET BY THIS EVENING. A STRAY SHOWER
CANNOT BE COMPLETELY RULED OUT DURING THE AFTERNOON. THE WIND
FORECAST BECOMES TRICKY THIS AFTERNOON AS THERE COULD BE A BATTLE
BETWEEN EAST/NORTHEAST WINDS AND GUSTY SOUTHWEST WINDS IN THE
VICINITY OF THE TERMINAL. WITH THE POTENTIAL FOR A SHOWER AND
SIGNIFICANT CLOUD COVER...WITH ERR ON THE SIDE OF LIGHTER
EAST/NORTHEAST WINDS FOR THE 12Z TAF. IN REALITY...WINDS COULD FAVOR
EITHER DIRECTION BETWEEN ROUGHLY 19Z-01Z THIS AFTERNOON. QUIET
WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY...WITH ANOTHER VERY
SLIGHT CHANCE OF SHOWERS TUESDAY EVENING.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...INCREASING SOUTHWEST WINDS EXPECTED ACROSS THE WESTERN
MOJAVE DESERT THIS MORNING (MAINLY SOUTH OF A KNID-KDRA-KSGU LINE).
TO THE NORTH...LIGHTER WINDS ARE EXPECTED TO FAVOR TYPICAL DIURNAL
TRENDS IN VALLEY LOCATIONS. IT`S UNCLEAR WHETHER THE SOUTHWEST
WINDS WILL MAKE IT INTO THE LAS VEGAS VALLEY...WITH KHND BEING THE
MOST LIKELY LOCATION IF THEY DO. CIGS ARE EXPECTED TO DROP TO 5-8K
FEET AS A WEAK SYSTEM PASSES THROUGH THE REGION. THIS WILL ALSO
BRING A SLIGHT CHANCE OF SHOWERS TO THE REGION...MAINLY NORTH OF LAS
VEGAS...HOWEVER A FEW STRAY SHOWERS TO THE SOUTH CANNOT BE RULED
OUT. QUIET WEATHER IS EXPECTED OVERNIGHT INTO TUESDAY MORNING...WITH
ANOTHER SLIGHT CHANCE OF SHOWERS ACROSS THE REGION TUESDAY.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED.
PLEASE REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD
OPERATING PROCEDURES.
&&
$$
SHORT TERM/AVIATION...WOLCOTT
LONG TERM.............SHAFER
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
832 PM CST TUE JAN 19 2016
.UPDATE...
ISSUED AT 826 PM CST TUE JAN 19 2016
QUICK UPDATE TO EXPAND THE DENSE FOG ADVISORY INTO
MCKENZIE...DUNN...GRANT AND SIOUX COUNTIES PER OBSERVED TRENDS
0230 UTC.
UPDATE ISSUED AT 721 PM CST TUE JAN 19 2016
WEBCAM AND SURFACE OBSERVATION TRENDS THROUGH 0115 UTC DEPICT
VISIBILITY RAPIDLY FALLING ACROSS NORTHWEST AND INTO CENTRAL NORTH
DAKOTA WITH STRATUS BUILD DOWN. THUS...HAVE ISSUED A DENSE FOG
ADVISORY FOR THESE AREAS THROUGH 16 UTC WEDNESDAY MORNING. THE
SPATIAL COVERAGE OF THE ADVISORY IS FITTED TO CURRENT AREAS WITH
DENSE FOG...EXTRAPOLATED TO VISIBILITY TRENDS IN THE 21-00 UTC
HRRR ITERATIONS. A POTENTIAL EXPANSION OF THE ADVISORY IS
POSSIBLE LATER THIS EVENING.
UPDATE ISSUED AT 637 PM CST TUE JAN 19 2016
GIVEN TRENDS IN THE 21-23 UTC HRRR ITERATION VISIBILITY FORECASTS...EXPANDED
THE MENTION OF FOG TO ALL OF WESTERN AND CENTRAL NORTH DAKOTA
TONIGHT INTO WEDNESDAY MORNING. PATCHY DENSE FOG HAS ALREADY
DEVELOPED ACROSS NORTHWEST NORTH DAKOTA AS OF 00 UTC...AND EXPECT
A SLOW EXPANSION OF FOG WITH STRATUS BUILD DOWN THROUGH THE NIGHT.
A DENSE FOG ADVISORY MAY BE NEEDED.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
LOOKS LIKE THE VERY COLD AIR WILL TAKE AN EXIT FOR AWHILE.
CONCERNS NOW FOR THIS SHORT TERM PERIOD WILL FOCUS ON THE
POTENTIAL FOR FOG TONIGHT. MESOSCALE MODELS HAVE BEEN CONSISTENTLY
FORECASTING A SHALLOW COOL AND MOIST BOUNDARY LAYER FREE OF
CLOUDS ABOVE. HRRR DEVELOPS WIDESPREAD LOW VISIBILITIES THIS
EVENING AND OVERNIGHT.
SATELLITE TRENDS SO FAR TODAY SHOW THE STRATUS LAYER ERODING
IN LOW LEVEL WARM ADVECTION ACROSS WESTERN NORTH DAKOTA. THIS
PROCESS WILL BE DISRUPTED THIS EVENING AS SUNSET APPROACHES.
DURING THE COOLING HOURS IN THE EVENING EXPECT FOG TO FORM IN THE
CLEARING ZONE WITH THE CLOUDS CREEPING BACK WEST. THIS WILL MAKE
MIN TEMPERATURES IN THE CLEARING AREA A CHALLENGE. SO FAR HAVE
ACCEPTED THE CONSSHORT GUIDANCE GIVING LOWER TEENS ACROSS THE
WEST AND SINGLE DIGITS ABOVE ZERO EAST.
ON WEDNESDAY THE NEXT SHORTWAVE IN A SERIES OF SHORTWAVES WILL
BRING AN INCREASE IN MID/HIGH CLOUDS AND BREAK OF THE BOUNDARY LAYER
FOG DURING FORENOON. A SLIGHT CHANCE OF SNOW SEEMS REASONABLE BY
LATE AFTERNOON FAR WEST. HIGH WEDNESDAY IN THE 20S TO MID 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
WEDNESDAY NIGHT THROUGH THURSDAY...COLD AIR ADVECTION AND A CHANCE
OF LIGHT SNOW WILL BEGIN POURING INTO SOUTHWEST NORTH DAKOTA
WEDNESDAY EVENING AS A SURFACE LOW AND ASSOCIATED MID LEVEL
SHORTWAVE SCOOT FROM SOUTHEAST MONTANA INTO SOUTH DAKOTA. THIS WILL
BE FOLLOWED BY ANOTHER SHORTWAVE THURSDAY...AS IT MOVES FROM WEST TO
EAST DURING THE DAY. THERE HAD BEEN SOME CONCERN FOR LIGHT FREEZING
RAIN WEDNESDAY EVENING...BUT THE NAM/SREF/GFS BUFKIT SOUNDINGS
INDICATE THAT IF IT DID DEVELOP...IT WOULD BE BRIEF...WITH A FAIRLY
QUICK TRANSITION TO LIGHT SNOW. NOT SEEING AN EXTENDED PERIOD OF
UPWARD VERTICAL MOTION WITH WITHIN THE SUPERCOOLED WATER DROPLET
REGIME...AND THE TRANSITION TIME FOR ANY GIVEN SOUNDING TO REACH
COLDER/HIGHER LEVELS OF SATURATION IS ACHIEVED FAIRLY QUICKLY
WEDNESDAY NIGHT. THUS...GIVEN THE BRIEF TIME AND ISOLATED COVERAGE
OF LIGHT FREEZING RAIN POTENTIAL...HAVE DECIDED TO STICK WITH THE
GIVEN FORECAST WHICH KEEPS A MENTION OF ONLY LIGHT SNOW. WILL
REVISIT THE SOUNDINGS AGAIN TONIGHT AND WEDNESDAY FOR ANY
SIGNIFICANT CHANGES TO THE ABOVE THINKING. OTHERWISE...CHANCES FOR
LIGHT SNOW WILL EXPAND INTO CENTRAL NORTH DAKOTA THROUGH THE DAY
THURSDAY. SNOWFALL ACCUMULATIONS THROUGH THURSDAY EVENING ARE
FORECAST AROUND A HALF INCH WEST AND CENTRAL...WITH AN ISOLATED SPOT
OF ONE INCH IN THE SOUTHWEST. THE CHANCE OF LIGHT SNOW EXITS THE
SOUTHERN JAMES RIVER VALLEY THURSDAY EVENING. WITH ONGOING COLD AIR
ADVECTION...HIGH TEMPERATURES THURSDAY WILL BE 5 TO 10 DEGREES
COLDER FROM WEDNESDAY...WHICH PUTS HIGHS THURSDAY FROM AROUND 10F
ABOVE IN THE TURTLE MOUNTAINS TO 25F SOUTHWEST.
THURSDAY NIGHT THROUGH SATURDAY...FOLLOWING THE ABOVE SHORTWAVE IS
AN UPPER LEVEL RIDGE WHICH WILL SHIFT FROM THE NORTHERN ROCKIES INTO
THE NORTHERN HIGH PLAINS FRIDAY INTO MOST OF SATURDAY. STRONG LOW
LEVEL WARM AIR ADVECTION FRIDAY AND SATURDAY WILL RESULT IN A
MODERATING TREND ALONG WITH DRY CONDITIONS. HIGHS FRIDAY WILL RANGE
FROM AROUND 20 IN THE JAMES RIVER VALLEY TO 40 WEST. BY SATURDAY
HIGHS WILL RANGE BETWEEN 30F AND 40F ACROSS WESTERN AND CENTRAL
NORTH DAKOTA.
THE WARMING TREND WILL COME TO AN END SATURDAY EVENING...AS A COLD
FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST. THIS LEADS TO A CHANCE OF
SNOW AND COLDER TEMPERATURES SUNDAY. HIGHS SUNDAY THROUGH TUESDAY
ARE NEARLY THE SAME EACH DAY WITH HIGHS IN THE UPPER TEENS IN THE
TURTLE MOUNTAINS TO 20S ELSEWHERE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 826 PM CST TUE JAN 19 2016
WIDESPREAD LIFR/VLIFR CONDITIONS IN FREEZING FOG AND STRATUS
EXPANDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH TONIGHT
AND INTO WEDNESDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST /9 AM MST/ WEDNESDAY FOR
NDZ001-002-009>011-017>023-034>036-042-045>047-050.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...KS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
725 PM CST TUE JAN 19 2016
.UPDATE...
ISSUED AT 721 PM CST TUE JAN 19 2016
WEBCAM AND SURFACE OBSERVATION TRENDS THROUGH 0115 UTC DEPICT
VISIBILITY RAPIDLY FALLING ACROSS NORTHWEST AND INTO CENTRAL NORTH
DAKOTA WITH STRATUS BUILD DOWN. THUS...HAVE ISSUED A DENSE FOG
ADVISORY FOR THESE AREAS THROUGH 16 UTC WEDNESDAY MORNING. THE
SPATIAL COVERAGE OF THE ADVISORY IS FITTED TO CURRENT AREAS WITH
DENSE FOG...EXTRAPOLATED TO VISIBILITY TRENDS IN THE 21-00 UTC
HRRR ITERATIONS. A POTENTIAL EXPANSION OF THE ADVISORY IS
POSSIBLE LATER THIS EVENING.
UPDATE ISSUED AT 637 PM CST TUE JAN 19 2016
GIVEN TRENDS IN THE 21-23 UTC HRRR ITERATION VISIBILITY FORECASTS...EXPANDED
THE MENTION OF FOG TO ALL OF WESTERN AND CENTRAL NORTH DAKOTA
TONIGHT INTO WEDNESDAY MORNING. PATCHY DENSE FOG HAS ALREADY
DEVELOPED ACROSS NORTHWEST NORTH DAKOTA AS OF 00 UTC...AND EXPECT
A SLOW EXPANSION OF FOG WITH STRATUS BUILD DOWN THROUGH THE NIGHT.
A DENSE FOG ADVISORY MAY BE NEEDED.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
LOOKS LIKE THE VERY COLD AIR WILL TAKE AN EXIT FOR AWHILE.
CONCERNS NOW FOR THIS SHORT TERM PERIOD WILL FOCUS ON THE
POTENTIAL FOR FOG TONIGHT. MESOSCALE MODELS HAVE BEEN CONSISTENTLY
FORECASTING A SHALLOW COOL AND MOIST BOUNDARY LAYER FREE OF
CLOUDS ABOVE. HRRR DEVELOPS WIDESPREAD LOW VISIBILITIES THIS
EVENING AND OVERNIGHT.
SATELLITE TRENDS SO FAR TODAY SHOW THE STRATUS LAYER ERODING
IN LOW LEVEL WARM ADVECTION ACROSS WESTERN NORTH DAKOTA. THIS
PROCESS WILL BE DISRUPTED THIS EVENING AS SUNSET APPROACHES.
DURING THE COOLING HOURS IN THE EVENING EXPECT FOG TO FORM IN THE
CLEARING ZONE WITH THE CLOUDS CREEPING BACK WEST. THIS WILL MAKE
MIN TEMPERATURES IN THE CLEARING AREA A CHALLENGE. SO FAR HAVE
ACCEPTED THE CONSSHORT GUIDANCE GIVING LOWER TEENS ACROSS THE
WEST AND SINGLE DIGITS ABOVE ZERO EAST.
ON WEDNESDAY THE NEXT SHORTWAVE IN A SERIES OF SHORTWAVES WILL
BRING AN INCREASE IN MID/HIGH CLOUDS AND BREAK OF THE BOUNDARY LAYER
FOG DURING FORENOON. A SLIGHT CHANCE OF SNOW SEEMS REASONABLE BY
LATE AFTERNOON FAR WEST. HIGH WEDNESDAY IN THE 20S TO MID 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
WEDNESDAY NIGHT THROUGH THURSDAY...COLD AIR ADVECTION AND A CHANCE
OF LIGHT SNOW WILL BEGIN POURING INTO SOUTHWEST NORTH DAKOTA
WEDNESDAY EVENING AS A SURFACE LOW AND ASSOCIATED MID LEVEL
SHORTWAVE SCOOT FROM SOUTHEAST MONTANA INTO SOUTH DAKOTA. THIS WILL
BE FOLLOWED BY ANOTHER SHORTWAVE THURSDAY...AS IT MOVES FROM WEST TO
EAST DURING THE DAY. THERE HAD BEEN SOME CONCERN FOR LIGHT FREEZING
RAIN WEDNESDAY EVENING...BUT THE NAM/SREF/GFS BUFKIT SOUNDINGS
INDICATE THAT IF IT DID DEVELOP...IT WOULD BE BRIEF...WITH A FAIRLY
QUICK TRANSITION TO LIGHT SNOW. NOT SEEING AN EXTENDED PERIOD OF
UPWARD VERTICAL MOTION WITH WITHIN THE SUPERCOOLED WATER DROPLET
REGIME...AND THE TRANSITION TIME FOR ANY GIVEN SOUNDING TO REACH
COLDER/HIGHER LEVELS OF SATURATION IS ACHIEVED FAIRLY QUICKLY
WEDNESDAY NIGHT. THUS...GIVEN THE BRIEF TIME AND ISOLATED COVERAGE
OF LIGHT FREEZING RAIN POTENTIAL...HAVE DECIDED TO STICK WITH THE
GIVEN FORECAST WHICH KEEPS A MENTION OF ONLY LIGHT SNOW. WILL
REVISIT THE SOUNDINGS AGAIN TONIGHT AND WEDNESDAY FOR ANY
SIGNIFICANT CHANGES TO THE ABOVE THINKING. OTHERWISE...CHANCES FOR
LIGHT SNOW WILL EXPAND INTO CENTRAL NORTH DAKOTA THROUGH THE DAY
THURSDAY. SNOWFALL ACCUMULATIONS THROUGH THURSDAY EVENING ARE
FORECAST AROUND A HALF INCH WEST AND CENTRAL...WITH AN ISOLATED SPOT
OF ONE INCH IN THE SOUTHWEST. THE CHANCE OF LIGHT SNOW EXITS THE
SOUTHERN JAMES RIVER VALLEY THURSDAY EVENING. WITH ONGOING COLD AIR
ADVECTION...HIGH TEMPERATURES THURSDAY WILL BE 5 TO 10 DEGREES
COLDER FROM WEDNESDAY...WHICH PUTS HIGHS THURSDAY FROM AROUND 10F
ABOVE IN THE TURTLE MOUNTAINS TO 25F SOUTHWEST.
THURSDAY NIGHT THROUGH SATURDAY...FOLLOWING THE ABOVE SHORTWAVE IS
AN UPPER LEVEL RIDGE WHICH WILL SHIFT FROM THE NORTHERN ROCKIES INTO
THE NORTHERN HIGH PLAINS FRIDAY INTO MOST OF SATURDAY. STRONG LOW
LEVEL WARM AIR ADVECTION FRIDAY AND SATURDAY WILL RESULT IN A
MODERATING TREND ALONG WITH DRY CONDITIONS. HIGHS FRIDAY WILL RANGE
FROM AROUND 20 IN THE JAMES RIVER VALLEY TO 40 WEST. BY SATURDAY
HIGHS WILL RANGE BETWEEN 30F AND 40F ACROSS WESTERN AND CENTRAL
NORTH DAKOTA.
THE WARMING TREND WILL COME TO AN END SATURDAY EVENING...AS A COLD
FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST. THIS LEADS TO A CHANCE OF
SNOW AND COLDER TEMPERATURES SUNDAY. HIGHS SUNDAY THROUGH TUESDAY
ARE NEARLY THE SAME EACH DAY WITH HIGHS IN THE UPPER TEENS IN THE
TURTLE MOUNTAINS TO 20S ELSEWHERE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 721 PM CST TUE JAN 19 2016
WIDESPREAD LIFR/VLIFR CONDITIONS IN FREEZING FOG AND STRATUS
EXPANDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH TONIGHT
AND INTO WEDNESDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST WEDNESDAY FOR NDZ001-002-
009>011-019>023-034>036-046-047-050.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...KS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
840 PM EST TUE JAN 19 2016
.SYNOPSIS...
AN UPPER LEVEL TROUGH ALONG WITH AN UPPER LEVEL DISTURBANCE
WILL COMBINE TO BRING SNOW TO THE AREA WEDNESDAY. HIGH PRESSURE
AND DRY AIR WILL RETURN FOR THURSDAY...UNTIL A LARGE AREA OF LOW
PRESSURE BRINGS ANOTHER WINTER SYSTEM TO THE REGION ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
HIGH CLOUDS ARE SPREADING INTO THE FORECAST AREA THIS
EVENING...AND RADAR ECHOES HAVE EXTENDED INTO SOUTHWEST INDIANA.
SOME OF THESE ECHOES ARE VIRGA...WITH THE INITIAL AREAS OF SNOW
JUST NOW REACHING SOUTHERN ILLINOIS. BASED ON CURRENT TRENDS AND
RECENT HRRR/RAP FORECAST CYCLES...THE TIMING FOR SNOW WAS SPED UP
SLIGHTLY. ALSO...POPS WERE INCREASED TO 100 PERCENT FOR MUCH OF
THE FORECAST AREA.
THE LATEST GUIDANCE SUGGESTS THAT THE CURRENT SNOWFALL FORECAST IS
STILL ON TRACK...FALLING VERY CLOSE TO THE SREF MEAN...AND IN
BETWEEN THE HIGHER NAM AND LOWER RAP SOLUTIONS.
PREVIOUS DISCUSSION >
CURRENTLY MOSTLY CLEAR SKIES WITH SOME PASSING CIRRUS AS THE NEXT
UPPER LEVEL SYSTEM CAN CLEARLY BE SEEN ON VISIBLE OFF TO OUR WEST.
WEDNESDAY MORNING AN UPPER LEVEL TROUGH WILL DIVE SOUTHEAST AND
PUSH INTO OUR FAR WESTERN ZONES BETWEEN 4 AM AND 7 AM. OMEGA
VALUES ON BOTH THE GFS AND NAM SHOW WEAK LIFT MOVING ACROSS THE
AREA RIGHT AROUND 6 AM ALONG WITH ISENTROPIC UPGLIDE COMMENCING.
THINK THE ONSET OF SNOW MIGHT BE DELAYED A BIT AS GFS AND NAM
FORECAST SOUNDINGS SHOW DRY AIR AROUND 750 MB SLOWLY ERODING
WEDNESDAY MORNING. THIS MAKES SENSE AS 12 Z 700 MB ANALYSIS SHOWED
DEWPOINT DEPRESSIONS OF GREATER THAN 20 DEGREES JUST OFF TO OUR
WEST.
LATEST SUITE OF HIGH RES AND GLOBAL MODELS HAVE SHOWN A SLIGHT
INCREASE IN AMOUNTS OF SNOWFALL ACROSS THE AREA BUT AM EXPECTING 1-2
INCHES WITH HIGHER AMOUNTS POSSIBLE ACROSS THE SOUTHWEST OF THE CWA.
THE TIMING OF THE SNOWFALL ALSO LOOKS TO OCCUR DURING THE MORNING
COMMUTE. GIVEN THE POTENTIAL IMPACTS DURING THE MORNING COMMUTE
AND SLIGHTLY HIGHER TOTALS HAVE EXTENDED THE WINTER WEATHER ADVISORY
ONE TIER OF COUNTIES NORTH.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
WEDNESDAY MORNING WILL START OFF WITH SNOW SPREADING ACROSS THE
CWA WITH HIGHER TOTALS FORECASTED ACROSS THE SOUTHERN PARTS OF THE
FORECAST AREA. FORECAST SOUNDINGS ON THE NAM AND GFS THEN SHOW
THE SNOW STARTING TO COME TO AN END WEST TO EAST BETWEEN NOON AND
2 PM. ACROSS OUR FAR EASTERN COUNTIES SNOW SHOULD COME TO AN END
BY 7 PM. FORECAST SOUNDINGS ON BOTH THE GFS AND NAM ALSO SHOW DRY
AIR STARTING TO MOVE IN AT 500 MB AS THE MAIN SHORTWAVE MOVES
OVERHEAD. THE DGZ APPEARS TO BE BETWEEN 550 AND 700 MB. THE
DEWPOINT AND TEMPERATURE LINES ON THE FORECAST SOUNDINGS CONTINUE
TO PULL APART IN THE AFTERNOON. THIS WILL BRING AN END TO THE
SNOW. THE TEMPERATURE PROFILE IS ALSO ISOTHERMAL RIGHT AROUND -10
DEGREES FROM 900 TO 700 MB. A LITTLE COLDER PROFILE WILL KEEP THE
SNOW GOING SLIGHTLY LONGER AS ICE CRYSTALS WILL BE ABLE TO GROW
WHERE AS A SLIGHTLY WARMER PROFILE WOULD FAVOR A QUICKER END TO
THE SNOW AND A POSSIBLE BRIEF PERIOD OF DRIZZLE. FOR NOW HAVE LEFT
THE MENTION OF DRIZZLE OUT AS CONFIDENCE REMAINS LOW.
WEDNESDAY EVENING SNOW WILL COME TO AN END AS A WEAK COLD FRONT
CROSSES THE AREA. SURFACE HIGH PRESSURE WILL THEN MOVE OVERHEAD
THURSDAY MORNING ALLOWING WINDS TO GO CALM. THURSDAY MORNING THE
GFS... EURO AND NAM ALL SHOW A CIRRUS SHIELD MOVING IN FROM THE
SOUTHWEST ALONG WITH SOME LOW CLOUDS LINGERING. GIVEN THE ABOVE...
LOW TEMPERATURES THURSDAY MORNING WILL LIKELY BE A TAD WARMER
THAN WEDNESDAY MORNINGS TEMPS. DURING THE DAY THURSDAY CIRRUS WILL
CONTINUE WITH SURFACE RIDGING WEAKENING ACROSS THE AREA AS THE
NEXT SYSTEM APPROACHES FROM THE WEST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
MAIN FOCUS IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR A
WINTER STORM TO AFFECT THE OHIO VALLEY REGION. THE IMPETUS FOR WHAT
WILL DEVELOP INTO A CLOSED MID LEVEL CIRCULATION EITHER OVER THE TN
VLY OR THE DEEP SOUTH IS STILL OFF THE WEST COAST ATTM...SO CAUTION
MUST BE USED IN THE FORECAST DUE TO THE OSCILLATIONS IN THE POSITION
AND TRACK OF THE MID LEVEL CIRCULATION. MODELS TEND TO HAVE ISSUES
WITH THE CLOSING OFF OF SUCH SYSTEMS...AND GIVEN THAT THE ENERGY IS
STILL OFF THE WEST COAST...THERE WILL BE TIME FOR OSCILLATIONS TO
CONTINUE UNTIL PERHAPS 12Z WEDNESDAY WHEN THE ENERGY WILL BE FULLY
SAMPLED.
THAT BEING SAID...OF THE MAIN OPERATIONAL MODELS FROM THE 01.19.12Z
RUN...THE ECMWF HAS TAKEN A MORE SOUTHERN TRACK ACROSS THE DEEP
SOUTH VERSUS THE OTHER MODELS (NAM...GFS...AND CMC). AS TO NOT JUMP
ON THE PURE 12Z ECMWF SOLUTION...WHICH WOULD BRING A PCPN SHIELD/MID
LEVEL DEFORMATION AXIS ONLY AS FAR NORTH AS THE OHIO RIVER...HAVE
TAKEN A BLEND OF THE 12Z GFS AND THE PREVIOUS 00Z ECMWF WHICH KEEPS
SOME CONTINUITY TO THE GOING FORECAST AND ALLOWS FOR SOME POTENTIAL
FOR A MORE NORTHERN TRACK TO BE A POSSIBLE SOLUTION. THUS...THE
CURRENT FORECAST WILL ALLOW PCPN SHIELD/MID LVL DEFORMATION AXIS
PUSH NORTHWARD TOWARD THE OHIO RIVER THURSDAY NIGHT...ALLOWING IT TO
PIVOT AS FAR NORTH/NORTHWEST AS THE I-71 CORRIDOR...AND THEN ALLOW
IT TO SHIFT EAST FRIDAY NIGHT INTO SATURDAY AS A COASTAL LOW/ENERGY
TRANSFER TAKES PLACE. BASED ON THIS SCENARIO...PCPN SHOULD REMAIN AS
SNOW WITH THE POTENTIAL FOR SIGNIFICANT SNOW ACCUMULATIONS ALONG AND
SOUTHEAST OF THE I-71 CORRIDOR AND PARTICULARY ALONG AND SOUTH OF
THE OHIO RIVER VALLEY. THUS...AT THIS JUNCTURE...4 OR MORE INCHES OF
SNOW MAY BE POSSIBLE ALONG AND SOUTH OF THE I-71 CORRIDOR WITH 6 OR
MORE INCHES POSSIBLE ALONG AND SOUTH OF THE OHIO RIVER. AGAIN...A
TRACK FARTHER SOUTH WOULD ONLY IMPACT LOCATIONS ALONG AND SOUTH OF
THE OHIO RIVER...AND A TRACK FARTHER NORTH WOULD PUSH THE THREAT
TOWARD THE I-71 CORRIDOR. AS THE COASTAL LOW TAKES SHAPE AND MOVES
NEAR AND OFF THE NEW ENGLAND COAST SATURDAY AFTERNOON AND
NIGHT...PCPN WILL TAPER OFF OVER THE REGION AS SURFACE HIGH PRESSURE
BUILDS BACK INTO THE OHIO VALLEY. AS FOR TEMPERATURES...HAVE TAKEN
BLEND OF PREVIOUS FORECAST AND THE 12Z GFS/00Z ECMWF. SOME
ADJUSTMENTS MAY HAVE TO BE MADE TO CURRENT VALUES DEPENDING ON WHERE
AND THE AMOUNT OF SNOW COVER WHICH MAY FALL...WHICH WILL HAVE AN
ALBEDO EFFECT/RADIATIONAL COOLING EFFECT.
FOR SUNDAY INTO MONDAY...HIGH PRESSURE WILL MOVE OFF TO THE EAST AS
THE NEXT LOW PRESSURE SYSTEM AND FRONT MOVE IN FROM THE WEST. THERE
ARE SOME TIMING AND STRENGTH DIFFERENCE AT THIS POINT...SO WILL
BRING A GRADUAL CHANCE OF PCPN FROM WEST TO EAST MONDAY AFTERNOON
INTO MONDAY NIGHT...WITH THE CHANCE CONTINUING INTO TUESDAY AS THE
SYSTEM MOVES THROUGH. TEMPERATURES WILL BE CRITICAL TO PTYPE.
CURRENTLY HAVE RAIN/SNOW FOR NORTHERN AREAS AND RAIN FOR SOUTHERN
AREAS...WITH A CHANGEOVER TO ALL SNOW ON TUESDAY IN THE WAKE OF THE
LOW AND FRONT. A BLEND OF THE TEMPERATURES HAVE BEEN USED WITH HIGHS
IN THE 30S TO AROUND 40 AND LOWS MAINLY IN THE 30S.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE MAJORITY OF THE OVERNIGHT
HOURS...BEFORE SNOW MOVES INTO THE REGION EARLY WEDNESDAY MORNING.
CLOUDS WILL GRADUALLY LOWER AND THICKEN (ESPECIALLY AFTER
MIDNIGHT)...BUT SHOULD REMAIN VFR UNTIL AFTER THE SNOW BEGINS.
ONCE SNOW STARTS...CONDITIONS WILL DETERIORATE RAPIDLY. IFR
VISIBILITIES ARE A CERTAINTY...AS WELL AS MVFR (POSSIBLY IFR)
CEILINGS. WINDS WILL REMAIN VERY LIGHT THROUGH THE ENTIRE FORECAST
PERIOD.
AFTER THE SNOW ENDS...MVFR CEILINGS WILL LIKELY PERSIST THROUGH
THE REST OF THE DAY...AND POSSIBLY INTO THE OVERNIGHT HOURS.
OUTLOOK...MVFR CEILINGS MAY CONTINUE THROUGH WEDNESDAY NIGHT AND
INTO EARLY THURSDAY MORNING. MVFR/IFR CONDITIONS ARE EXPECTED
WITH PRECIPITATION ON FRIDAY INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST WEDNESDAY FOR
OHZ070>072-077>081-088.
KY...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST WEDNESDAY FOR
KYZ089>100.
IN...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST WEDNESDAY FOR
INZ066-073>075-080.
&&
$$
SYNOPSIS...HAINES
NEAR TERM...HAINES/HATZOS
SHORT TERM...HAINES
LONG TERM...HICKMAN
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS Tulsa OK
909 PM CST TUE JAN 19 2016
...UPDATE...
.DISCUSSION...
Precipitation across far eastern OK and northwest AR has been
convection in nature...resulting in pockets of brief moderate
sleet/freezing rain this evening. This has made for very slick
conditions across the region...especially in and around the Fort
Smith area and into parts of Madison county. HRRR trends are for
the heavier precipitation to shift east of the region after
06z...although could see a few more hours of light freezing
drizzle. Will leave the winter weather advisory as is for
now...but it may end of being cancelled a bit earlier than 12z.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 26 40 33 40 / 40 0 40 40
FSM 31 43 34 42 / 70 0 40 60
MLC 31 43 36 44 / 50 0 30 50
BVO 24 39 29 38 / 30 0 40 40
FYV 28 40 31 38 / 80 0 40 60
BYV 26 38 28 36 / 80 0 30 60
MKO 30 40 34 41 / 60 0 40 50
MIO 25 40 30 38 / 60 0 40 50
F10 29 40 34 42 / 50 0 30 40
HHW 35 47 38 48 / 50 0 50 60
&&
.TSA Watches/Warnings/Advisories...
OK...Winter Weather Advisory until 6 AM CST Wednesday for OKZ057-058-
062-063-068-069-072.
AR...Winter Weather Advisory until 6 AM CST Wednesday for ARZ001-002-
010-011-019-020-029.
&&
$$
SHORT TERM...18
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
745 PM CST TUE JAN 19 2016
.DISCUSSION...
LATEST SURFACE ANALYSIS DEPICTS SNOW ACROSS THE NORTHERN HALF OF
MO. FREEZING RAIN AND SOME SLEET OVER SRN MO...SOME FRZ RAIN
ACROSS NRN AR. 00Z OHX SOUNDING REVEALED 850 MB TEMPS THAT WERE
SLIGHTLY WARMER THAN THE MODELS. WET BULB ZERO PROFILES AT THE 850
MB LEVEL SHOWS A RATHER IMPRESSIVE WEDGE OF WARMING ACROSS AR.
PORTIONS OF NRN AR AND SRN MO SHOW FRZ RA WITH TEMPS IN THE LOWER
TO MID 20S...A TESTAMENT AS TO THE DEGREE OF WARM WEDGING THAT IS
ON GOING. SFC LOW IS CURRENTLY LOCATED OVER ERN OK. SLIGHT
INCREASE IN STRENGTH IS EXPECTED WITH THE WARM AIR IN THE 800MB TO
900 MB LEVEL WORKING EASTWARD. THIS WARMER AIR MAY VERY WELL MAKE
IT INTO OUR SOUTHWESTERN COUNTIES PRIOR TO 12Z. THUS...I WILL GO
AHEAD AND INCLUDE MORE IN THE WAY OF SLEET AND FREEZING RAIN
ACROSS OUR SOUTHWESTERN AND SOUTH CENTRAL AREAS.
LATEST HRRR SHOWS PATCHY LIGHT PRECIP MAKING IT ACROSS THE TN
RIVER AND REACHING THE GROUND JUST AFT MIDNIGHT. THE MORE
SIGNIFICANT PRECIP APPEARS TO MAKE IT ACROSS THE TN RIVER RIGHT
AROUND 6 AM. BASED ON THE LATEST 18Z NAM SOUNDINGS...IT STILL
LOOKS LIKE ALL SNOW NORTH OF I-40. BUT...THAT SOUTHWEST AREA IS A
CONCERN AND MORE IN THE WAY OF SLEET AND FREEZING RAIN COULD
FALL. AGAIN...WILL OPT TO MODIFY THE WX GRIDS TO REFLECT THIS
ACROSS SOUTHWEST AND SOUTHCENTRAL AREAS. SFC TEMPS STILL EXPECTED
TO WARM ABOVE FREEZING ACROSS THE SOUTHWEST BY 9AM...AND THEN ALL
BUT THE PLATEAU AREA BY NOON.
UPDATE OUT SHORTLY.
&&
.AVIATION...
18Z TAF DISCUSSION.
SURFACE LOW IN TEXAS WILL MOVE THIS WAY TONIGHT WITH INCREASING
CLOUDS ACROSS THE AREA WITH SNOW STARTING AT CLARKSVILLE AFTER
MIDNIGHT AND AT NASHVILLE BY 11Z. ACCUMULATING SNOW WILL THEN
WORK EASTWARD ACROSS THE MID STATE DURING THE DAY. THERE COULD BE
BRIEF PERIOD OF FREEZING RAIN FROM INTERSTATE 40 NORTHWARD BUT
FROM WHAT I`VE SEEN IT LOOKS LIKE MAINLY A SNOW EVENT BASED ON
FORECAST SOUNDINGS. SHOULD SEE PRECIP TAPER OFF DURING THE
AFTERNOON FROM THE WEST. NEEDLESS TO SAY FLYING CONDITIONS WILL GO
DOWNHILL AFTER MIDNIGHT TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 23 36 30 41 37 / 80 100 20 80 100
CLARKSVILLE 23 35 27 39 33 / 100 90 20 70 90
CROSSVILLE 19 32 28 40 37 / 50 100 20 70 90
COLUMBIA 25 37 33 44 38 / 60 100 20 90 100
LAWRENCEBURG 24 36 33 44 39 / 50 100 20 80 100
WAVERLY 24 37 30 40 34 / 100 90 20 80 90
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
WEDNESDAY FOR BEDFORD-CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-
DAVIDSON-DE KALB-DICKSON-FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-
HUMPHREYS-JACKSON-LAWRENCE-LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-
OVERTON-PERRY-PICKETT-PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-
SUMNER-TROUSDALE-VAN BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON.
&&
$$
SHORT TERM/AVIATION........31
LONG TERM..................21
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
914 PM CST TUE JAN 19 2016
.DISCUSSION...
SFC ANALYSIS AT 03Z SHOWED COLD FRONT STRETCHING FROM N TX THROUGH
W C TX WITH A FEW SHOWERS ALONG IT SE OF THE METROPLEX. BASED ON
LATEST HRRR TRENDS AND 00Z NAM...FRONT SHOULD CONTINUE TO PUSH
SOUTH INTO THE AREA THROUGH THE MORNING. FRONT MAY BE SLOW TO
RETURN NORTH AS A WARM FRONT TOMORROW.
STRONGER SHORT WAVE TROUGH PUSHES BY ON THURSDAY SO THINK THAT
WILL SUPPORT BETTER RAIN CHANCES AND PROBABLY SOME THUNDERSTORMS
GIVEN ENOUGH INSTABILITY. THAT SAID...MAY GET A DRY SLOT TO PUSH
THROUGH AND KICK STORMS EAST.
MAIN CHANGES TO THE FORECAST WERE TO UPDATE T/TD AS WELL AS
POP/WX/QPF FOR ONGOING TRENDS AND NEW MODEL GUIDANCE.
39
&&
.PREV DISCUSSION... /ISSUED 600 PM CST TUE JAN 19 2016/
AVIATION...
VFR CEILINGS THIS EVENING SHOULD GRADUALLY BECOME MVFR BETWEEN
06-09Z AS THE SOUTHERLY FLOW CONTINUES TO DRAW ADDITIONAL LOW
LEVEL MOISTURE IN TO THE AREA AHEAD OF AN APPROACHING COLD FRONT.
OVERNIGHT WINDS WILL BE LIGHT...BUT SHOULD PRODUCE ENOUGH MIXING
IN THE BOUNDARY LAYER TO INHIBIT WIDESPREAD FOG FORMATION.
A WEAK COLD FRONT SHOULD MOVE ACROSS THE WESTERN TERMINALS
BETWEEN 07-09Z AND THE HOUSTON METRO AREA BETWEEN 12-15Z...AND
OFF THE COAST BETWEEN 15-18Z...RESULTING IN A N/NW WIND SHIFT.
ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ALONG AND
AHEAD OF THE FRONT AS IT SAGS SOUTHWARD...SO I CONTINUE TO CARRY A
VCSH MENTION FOR ALL TERMINALS. THE FRONT IS EXPECTED TO REACH THE
COAST...HOWEVER THE NORTH FLOW WILL BE SHORT LIVED AT TERMINALS TO
THE SOUTH OF I-10. WINDS SHOULD BECOME LIGHT AND VARIABLE OVER THE
HOUSTON METRO AREA AND VEER TO THE NORTHEAST AT TERMINALS CLOSER
TO THE COAST BY TOMORROW AFTERNOON. 44
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 45 60 54 65 38 / 30 10 30 40 10
HOUSTON (IAH) 53 66 57 70 41 / 20 30 30 50 10
GALVESTON (GLS) 58 63 59 69 44 / 20 30 10 40 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1206 PM CST MON JAN 18 2016
.AVIATION...
/18Z TAFS/
NO AVIATION CONCERNS ARE EXPECTED IN THE FIRST 12-18 HOURS OF THE
TAF FORECAST WITH VFR CONDITIONS UNDERNEATH DRY NORTHWEST FLOW
ALOFT. A SURFACE RIDGE CENTERED FROM NORTHEAST OKLAHOMA TO THE MID
MISSISSIPPI VALLEY WILL CONTINUE MOVING SLOWLY EAST THROUGH THE
DAY. ALL AIRPORTS SHOULD SEE N/NE WINDS 4-6 KTS VEER SE BY LATE
AFTERNOON OR EARLY EVENING. DFW AIRPORT SHOULD BE ABLE TO GO TO A
SOUTH FLOW BY THEN.
THE BIGGEST CHALLENGE WILL BE THE ARRIVAL OF IFR CIGS INTO ALL THE
AIRPORTS BY...OR SHORTLY AFTER SUNRISE WITH A SHALLOW FRONTAL INVERSION
REMAINING IN PLACE. WARMING TEMPERATURES AND MIXING SHOULD HELP
CIGS RISE INTO THE MVFR CATEGORY BY MIDDAY TUESDAY...BEFORE SCATTERING
IN THE AFTERNOON.
LEE SURFACE CYCLOGENESIS WILL DEEPEN TO OUR NORTHWEST TONIGHT
WITH INCREASING SOUTH WINDS 10-15 KTS BY SUNRISE TUESDAY.
SUSTAINED WIND SPEEDS INCREASE TO BETWEEN 15-20 KTS WITH HIGHER
GUSTS BY MIDDAY TUESDAY.
AN APPROACHING SHORTWAVE DISTURBANCE AND ASSOCIATED COLD FRONT
ARRIVE TUESDAY EVENING WELL BEYOND THIS FORECAST. SHOWER ACTIVITY
ALONG THE FRONT WILL LIKELY OCCUR EAST OF ALL AIRPORTS WHERE
BETTER MOISTURE RESIDES.
05/
&&
.UPDATE...
SUNNY SKIES AND COOL CONDITIONS ARE IN STORE FOR THE REMAINDER OF
THE MLK HOLIDAY. TEMPERATURES THIS MORNING STARTED OUT IN THE
LOWER 20S TO LOWER 30S AND WILL REACH THE 40S TO MID 50S THIS
AFTERNOON. MADE SOME MINOR ADJUSTMENTS TO AFTERNOON HIGHS BASED ON
CURRENT TEMPS AND TRENDS BUT OTHERWISE NO SIGNIFICANT CHANGES WERE
NEEDED TO THE FORECAST.
JLDUNN
&&
.PREV DISCUSSION... /ISSUED 248 AM CST MON JAN 18 2016/
COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH
TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND
NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH
SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT
SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY
PROGRESSIVE.
MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD
COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES
ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE
ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE
TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST
SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT
MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER
THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED
ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE
SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE
METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING.
IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD
REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE...
HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID
50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE
SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE
TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER.
SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY
TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM
INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED
NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW
SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE
A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST
OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH.
WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER
SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS
TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW
PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS
WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR
ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO
DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH
THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE
WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR.
HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S.
A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS
THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL
TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS
A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON
SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID
TO UPPER 60S AREAWIDE.
DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING
WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR
RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE
DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH
POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 43 40 61 38 59 / 0 0 5 20 5
WACO, TX 47 41 64 42 63 / 0 0 0 10 5
PARIS, TX 43 35 55 38 56 / 0 0 10 40 5
DENTON, TX 42 38 60 35 57 / 0 0 5 20 5
MCKINNEY, TX 42 37 58 37 57 / 0 0 5 20 5
DALLAS, TX 44 40 61 39 59 / 0 0 5 20 5
TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5
CORSICANA, TX 47 42 61 44 61 / 0 0 5 20 5
TEMPLE, TX 49 41 66 44 64 / 0 0 0 10 5
MINERAL WELLS, TX 43 36 63 34 61 / 0 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1129 AM CST MON JAN 18 2016
.AVIATION...
VFR CONDITIONS IN PLACE AT KCDS AND WILL REMAIN SO THROUGH THE DAY
AS VFR CLOUD DECK DISSIPATES. KLBB AND KPVW REMAIN UNDER LIFR
CEILINGS WHICH WILL TAKE A BIT LONGER TO BURN OFF. TIMING REMAINS
UNCERTAIN WHEN THIS WILL OCCUR AS WESTERN EDGE HAS QUICKLY
DISSIPATED BUT STARTED TO SLOW DOWN THE FURTHER EAST THE CLEARING
LINE TRIED TO PUSH. CONFIDENCE IS LOW REGARDING WHEN KLBB/KPVW
WILL IMPROVE TO VFR SO TIMING IN THE TAF REMAINS UNCERTAIN. VFR
CONDITIONS WILL LAST THROUGH THE AFTERNOON INTO TONIGHT BUT THERE
IS A CHANCE OF SEEING LIFR CEILINGS DEVELOP AGAIN AT KPVW AND
KLBB. CONFIDENCE IS TOO LOW TO INCLUDE AT THIS TIME BUT THE
POSSIBILITY WILL BE THERE.
JORDAN
&&
.PREV DISCUSSION... /ISSUED 523 AM CST MON JAN 18 2016/
AVIATION...
LIFR TO IFR FOG HAVE PERSISTED AT KLBB AND KPVW RESPECTIVELY. AT
KCDS...VFR FOG HAPPENS ON OCCASION. HOWEVER...LIFR TO IFR CIGS
WERE OCCURRING AT ALL THREE TAF SITES. EXPECT CONDITIONS TO
IMPROVE TO VFR BY LATE MORNING/EARLY AFTERNOON. VFR DECKS WILL
RETURN BY THE EVENING-OVERNIGHT. OTHERWISE...LIGHT AND VARIABLE
WINDS WILL VEER TO THE SOUTH SOUTHWEST THIS AFTERNOON AT 10-12
KTS...BEFORE DECLINING A BIT SHORTLY AFTER SUNSET.
PREV DISCUSSION... /ISSUED 214 AM CST MON JAN 18 2016/
SHORT TERM...
THE COLD FRONT THAT MOVED IN ACROSS THE SOUTH PLAINS AND ROLLING
PLAINS YESTERDAY EVENING...USHERED IN LOW CLOUDS AND AIDED IN THE
DEVELOPMENT OF PATCHY AND AREAS /AND AT TIMES LOCALLY DENSE/ FOG.
JUST FOR PROSPECTIVE...KLBB REPORTED VIS DOWN TO 5SM DUE TO FOG
WHERE AT KPVW IT WAS DOWN TO 3/4SM AT ONE POINT. MOST MODEL
SOLUTIONS SUCH AS THE HRRR AND NAM HINT AT DENSE FOG BEING MORE
PREVALENT NEAR THE TEXAS AND NEW MEXICO BORDER EARLY THIS MORNING
AND SPREADING EASTWARD TO NEAR KLBB BY LATER THIS MORNING. WITH KCVN
AND KCVS REPORTING 1/4SM...THE AFOREMENTIONED MODELS COULD HAVE A
GOOD HANDLE ON THE SITUATION. WE WILL SEE LATER ON IN THE SHIFT IF A
DENSE FREEZING FOG ADVISORY WILL BE REQUIRED. DESPITE THE STRATUS
DECK...TEMPS STILL MANAGED TO CRATER INTO THE 20S PER 08Z
METARS...WHICH SUGGESTS THIS COLD AIRMASS IS A BIT POTENT. BY MID-
LATE MORNING...THE SFC RIDGE RESPONSIBLE FOR DRIVING THE COLD FRONT
AND HENCE PROVIDING THE CAA WILL BE GRADUALLY EXITING THE REGION TO
THE EAST...WHILST SFC LEE TROUGHING BECOMES ESTABLISHED. THIS WILL
LEAD TO SFC WINDS VEERING TO THE S-SW...WHICH IS A WIND COMPONENT
FAVORABLE FOR SCOURING OUT LOW CLOUDS AND FOG. MOST AREAS WILL
THEREFORE SEE THE SUN BY AT LEAST LATE AFTN. TEMPS TODAY WILL WARM
TO AROUND SEASONAL NORMS /50S/ WITH THE EXCEPTION OF THE ROLLING
PLAINS /40S/...WHERE CLOUDS WILL BE SLOWEST TO DEPART. AN AMPLIFIED
UA RIDGE TO OUR WEST WILL BE TRANSLATING TOWARDS THE REGION
TODAY...AND FILTER IN SOME HIGH LEVEL CLOUDINESS BY THIS EVENING-
TONIGHT...MAKING FOR A WARMER NIGHT /30S/.
LONG TERM...
A MILD...DRY...AND PERIODICALLY BREEZY PATTERN SETTING UP THIS
WEEK. SPLIT PROGRESSIVE FLOW OVER THE CONUS THIS WEEK WILL BRING A
SERIES OF SHORT WAVE TROUGHS ACROSS THE PLAINS...MOST NOTABLY
TUESDAY AND AGAIN WEDNESDAY BEFORE LARGER-AMPLITUDE UPPER RIDGING
MOVES FROM THE ROCKIES TO THE PLAINS LATE WEEK INTO NEXT WEEKEND.
OVERALL...WILL FAVOR THE WARMER END OF MOS GUIDANCE...AS THAT END
HAS BEEN SUPERIOR FOR MUCH OF THE LAST SEVERAL MONTHS AND MORE
RECENTLY OVER THE LAST WEEK OR SO. PRECIP CHANCES LOOK NEAR NIL.
THE BEST CHANCE STILL APPEARS TO BE WEDNESDAY NIGHT...BUT THAT
ALSO CONTINUES TO LOOK TO BE EAST OF THE REGION. LOCAL SUPERBLEND
INITIALIZATION HAS BROUGHT SLIGHT CHANCE MENTION BACK TO THE
ROLLING PLAINS...BUT STILL CONSIDER THAT SCENARIO HIGHLY UNLIKELY
AND HAVE KEPT PRECIP MENTION OUT. TEMPS SHOULD BE AT OR ABOVE TO
WELL ABOVE CLIMATOLOGY WITH THE EXCEPTION OF THURSDAY WHEN
AMPLIFICATION OF THE UPPER FLOW WILL ALLOW SOME COLDER AIR TO
SPILL DOWN THE PLAINS. EVEN THEN...TEMPS ARE LIKELY TO ONLY BE A
FEW DEGREES OR SO BELOW NORMS. TEMPS REBOUND QUICKLY WITH THE
RIDGING MOVING OVERHEAD WITH THE WARMEST DAY OF THE WEEK LOOKING
TO BE SATURDAY WITH THE RIDGE AXIS OVERHEAD.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1100 AM CST MON JAN 18 2016
.UPDATE...
SUNNY SKIES AND COOL CONDITIONS ARE IN STORE FOR THE REMAINDER OF
THE MLK HOLIDAY. TEMPERATURES THIS MORNING STARTED OUT IN THE
LOWER 20S TO LOWER 30S AND WILL REACH THE 40S TO MID 50S THIS
AFTERNOON. MADE SOME MINOR ADJUSTMENTS TO AFTERNOON HIGHS BASED ON
CURRENT TEMPS AND TRENDS BUT OTHERWISE NO SIGNIFICANT CHANGES WERE
NEEDED TO THE FORECAST.
JLDUNN
&&
.AVIATION...
/ISSUED 600 AM CST MON JAN 18 2016/
THE ONLY AVIATION WEATHER CONCERN WITH THIS TAF PACKAGE WILL BE
THE POTENTIAL FOR SOME BRIEF MVFR TO IFR CEILINGS THIS MORNING. AS
OF 530 AM...LIFR CEILINGS/VISIBILITY REMAINED OVER THE WEST TEXAS
AND SOUTHERN OKLAHOMA WHERE MOISTURE WAS TRAPPED UNDER THE SHALLOW
FRONTAL INVERSION. THE NAM AND GFS BOTH KEEP THE BEST MOISTURE ON
THE 925 MB SURFACE JUST TO THE NORTH AND WEST OF THE TAF SITES
THROUGH MIDDAY. SO FOR NOW HAVE DECIDED TO JUST MENTION SOME
SCATTERED LOW CLOUDS THROUGH THE MORNING AT ALL NORTH/CENTRAL
TEXAS TERMINALS BUT WILL HAVE TO WATCH CLOUD TRENDS CLOSELY.
OTHERWISE...EXPECT SCATTERED HIGH CLOUDS THIS AFTERNOON AND
EVENING. MVFR CEILINGS WILL BE LIKELY BY SUNRISE TUESDAY AS LOW
LEVEL MOISTURE SURGES NORTHWARD.
A NORTH WIND THIS MORNING WILL TURN TO THE EAST/SOUTHEAST THIS
AFTERNOON AND SOUTH TONIGHT. WIND SPEEDS WILL REMAIN BELOW 10
KNOTS THROUGH TONIGHT BUT WILL INCREASE BETWEEN 13 AND 15 KNOTS BY
SUNRISE TUESDAY.
79
&&
.PREV DISCUSSION... /ISSUED 248 AM CST MON JAN 18 2016/
COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH
TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND
NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH
SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT
SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY
PROGRESSIVE.
MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD
COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES
ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE
ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE
TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST
SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT
MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER
THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED
ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE
SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE
METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING.
IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD
REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE...
HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID
50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE
SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE
TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER.
SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY
TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM
INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED
NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW
SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE
A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST
OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH.
WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER
SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS
TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW
PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS
WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR
ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO
DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH
THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE
WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR.
HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S.
A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS
THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL
TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS
A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON
SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID
TO UPPER 60S AREAWIDE.
DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING
WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR
RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE
DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH
POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 43 40 61 38 59 / 0 0 5 20 5
WACO, TX 47 41 64 42 63 / 0 0 0 10 5
PARIS, TX 43 35 55 38 56 / 0 0 10 40 5
DENTON, TX 42 38 60 35 57 / 0 0 5 20 5
MCKINNEY, TX 42 37 58 37 57 / 0 0 5 20 5
DALLAS, TX 44 40 61 39 59 / 0 0 5 20 5
TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5
CORSICANA, TX 47 42 61 44 61 / 0 0 5 20 5
TEMPLE, TX 49 41 66 44 64 / 0 0 0 10 5
MINERAL WELLS, TX 43 36 63 34 61 / 0 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/82
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
600 AM CST MON JAN 18 2016
.AVIATION...
THE ONLY AVIATION WEATHER CONCERN WITH THIS TAF PACKAGE WILL BE
THE POTENTIAL FOR SOME BRIEF MVFR TO IFR CEILINGS THIS MORNING. AS
OF 530 AM...LIFR CEILINGS/VISIBILITY REMAINED OVER THE WEST TEXAS
AND SOUTHERN OKLAHOMA WHERE MOISTURE WAS TRAPPED UNDER THE SHALLOW
FRONTAL INVERSION. THE NAM AND GFS BOTH KEEP THE BEST MOISTURE ON
THE 925 MB SURFACE JUST TO THE NORTH AND WEST OF THE TAF SITES
THROUGH MIDDAY. SO FOR NOW HAVE DECIDED TO JUST MENTION SOME
SCATTERED LOW CLOUDS THROUGH THE MORNING AT ALL NORTH/CENTRAL
TEXAS TERMINALS BUT WILL HAVE TO WATCH CLOUD TRENDS CLOSELY.
OTHERWISE...EXPECT SCATTERED HIGH CLOUDS THIS AFTERNOON AND
EVENING. MVFR CEILINGS WILL BE LIKELY BY SUNRISE TUESDAY AS LOW
LEVEL MOISTURE SURGES NORTHWARD.
A NORTH WIND THIS MORNING WILL TURN TO THE EAST/SOUTHEAST THIS
AFTERNOON AND SOUTH TONIGHT. WIND SPEEDS WILL REMAIN BELOW 10
KNOTS THROUGH TONIGHT BUT WILL INCREASE BETWEEN 13 AND 15 KNOTS BY
SUNRISE TUESDAY.
79
&&
.PREV DISCUSSION... /ISSUED 248 AM CST MON JAN 18 2016/
COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH
TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND
NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH
SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT
SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY
PROGRESSIVE.
MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD
COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES
ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE
ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE
TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST
SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT
MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER
THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED
ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE
SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE
METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING.
IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD
REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE...
HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID
50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE
SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE
TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER.
SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY
TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM
INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED
NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW
SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE
A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST
OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH.
WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER
SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS
TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW
PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS
WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR
ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO
DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH
THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE
WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR.
HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S.
A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS
THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL
TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS
A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON
SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID
TO UPPER 60S AREAWIDE.
DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING
WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR
RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE
DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH
POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 44 40 61 38 59 / 0 0 5 20 5
WACO, TX 47 41 64 42 63 / 0 0 0 10 5
PARIS, TX 42 35 55 38 56 / 0 0 10 40 5
DENTON, TX 42 38 60 35 57 / 0 0 5 20 5
MCKINNEY, TX 43 37 58 37 57 / 0 0 5 20 5
DALLAS, TX 43 40 61 39 59 / 0 0 5 20 5
TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5
CORSICANA, TX 48 42 61 44 61 / 0 0 5 20 5
TEMPLE, TX 51 41 66 44 64 / 0 0 0 10 5
MINERAL WELLS, TX 44 36 63 34 61 / 0 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/91
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
523 AM CST MON JAN 18 2016
.AVIATION...
LIFR TO IFR FOG HAVE PERSISTED AT KLBB AND KPVW RESPECTIVELY. AT
KCDS...VFR FOG HAPPENS ON OCCASION. HOWEVER...LIFR TO IFR CIGS
WERE OCCURRING AT ALL THREE TAF SITES. EXPECT CONDITIONS TO
IMPROVE TO VFR BY LATE MORNING/EARLY AFTERNOON. VFR DECKS WILL
RETURN BY THE EVENING-OVERNIGHT. OTHERWISE...LIGHT AND VARIABLE
WINDS WILL VEER TO THE SOUTH SOUTHWEST THIS AFTERNOON AT 10-12
KTS...BEFORE DECLINING A BIT SHORTLY AFTER SUNSET.
&&
.PREV DISCUSSION... /ISSUED 214 AM CST MON JAN 18 2016/
SHORT TERM...
THE COLD FRONT THAT MOVED IN ACROSS THE SOUTH PLAINS AND ROLLING
PLAINS YESTERDAY EVENING...USHERED IN LOW CLOUDS AND AIDED IN THE
DEVELOPMENT OF PATCHY AND AREAS /AND AT TIMES LOCALLY DENSE/ FOG.
JUST FOR PROSPECTIVE...KLBB REPORTED VIS DOWN TO 5SM DUE TO FOG
WHERE AT KPVW IT WAS DOWN TO 3/4SM AT ONE POINT. MOST MODEL
SOLUTIONS SUCH AS THE HRRR AND NAM HINT AT DENSE FOG BEING MORE
PREVALENT NEAR THE TEXAS AND NEW MEXICO BORDER EARLY THIS MORNING
AND SPREADING EASTWARD TO NEAR KLBB BY LATER THIS MORNING. WITH KCVN
AND KCVS REPORTING 1/4SM...THE AFOREMENTIONED MODELS COULD HAVE A
GOOD HANDLE ON THE SITUATION. WE WILL SEE LATER ON IN THE SHIFT IF A
DENSE FREEZING FOG ADVISORY WILL BE REQUIRED. DESPITE THE STRATUS
DECK...TEMPS STILL MANAGED TO CRATER INTO THE 20S PER 08Z
METARS...WHICH SUGGESTS THIS COLD AIRMASS IS A BIT POTENT. BY MID-
LATE MORNING...THE SFC RIDGE RESPONSIBLE FOR DRIVING THE COLD FRONT
AND HENCE PROVIDING THE CAA WILL BE GRADUALLY EXITING THE REGION TO
THE EAST...WHILST SFC LEE TROUGHING BECOMES ESTABLISHED. THIS WILL
LEAD TO SFC WINDS VEERING TO THE S-SW...WHICH IS A WIND COMPONENT
FAVORABLE FOR SCOURING OUT LOW CLOUDS AND FOG. MOST AREAS WILL
THEREFORE SEE THE SUN BY AT LEAST LATE AFTN. TEMPS TODAY WILL WARM
TO AROUND SEASONAL NORMS /50S/ WITH THE EXCEPTION OF THE ROLLING
PLAINS /40S/...WHERE CLOUDS WILL BE SLOWEST TO DEPART. AN AMPLIFIED
UA RIDGE TO OUR WEST WILL BE TRANSLATING TOWARDS THE REGION
TODAY...AND FILTER IN SOME HIGH LEVEL CLOUDINESS BY THIS EVENING-
TONIGHT...MAKING FOR A WARMER NIGHT /30S/.
LONG TERM...
A MILD...DRY...AND PERIODICALLY BREEZY PATTERN SETTING UP THIS
WEEK. SPLIT PROGRESSIVE FLOW OVER THE CONUS THIS WEEK WILL BRING A
SERIES OF SHORT WAVE TROUGHS ACROSS THE PLAINS...MOST NOTABLY
TUESDAY AND AGAIN WEDNESDAY BEFORE LARGER-AMPLITUDE UPPER RIDGING
MOVES FROM THE ROCKIES TO THE PLAINS LATE WEEK INTO NEXT WEEKEND.
OVERALL...WILL FAVOR THE WARMER END OF MOS GUIDANCE...AS THAT END
HAS BEEN SUPERIOR FOR MUCH OF THE LAST SEVERAL MONTHS AND MORE
RECENTLY OVER THE LAST WEEK OR SO. PRECIP CHANCES LOOK NEAR NIL.
THE BEST CHANCE STILL APPEARS TO BE WEDNESDAY NIGHT...BUT THAT
ALSO CONTINUES TO LOOK TO BE EAST OF THE REGION. LOCAL SUPERBLEND
INITIALIZATION HAS BROUGHT SLIGHT CHANCE MENTION BACK TO THE
ROLLING PLAINS...BUT STILL CONSIDER THAT SCENARIO HIGHLY UNLIKELY
AND HAVE KEPT PRECIP MENTION OUT. TEMPS SHOULD BE AT OR ABOVE TO
WELL ABOVE CLIMATOLOGY WITH THE EXCEPTION OF THURSDAY WHEN
AMPLIFICATION OF THE UPPER FLOW WILL ALLOW SOME COLDER AIR TO
SPILL DOWN THE PLAINS. EVEN THEN...TEMPS ARE LIKELY TO ONLY BE A
FEW DEGREES OR SO BELOW NORMS. TEMPS REBOUND QUICKLY WITH THE
RIDGING MOVING OVERHEAD WITH THE WARMEST DAY OF THE WEEK LOOKING
TO BE SATURDAY WITH THE RIDGE AXIS OVERHEAD.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
248 AM CST MON JAN 18 2016
.DISCUSSION...
COLD AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS MORNING WITH
TEMPERATURES IN THE MID TO UPPER 20S NORTH OF INTERSTATE 20 AND
NORTH WINDS AROUND 10 MPH. THE COLDER AIR WILL CONTINUE TO PUSH
SOUTH THROUGH THE REMAINDER OF THE AREA LATER THIS MORNING BUT
SHOULD BE SHORT LIVED AS THE UPPER PATTERN REMAINS VERY
PROGRESSIVE.
MAIN CONCERN FOR TODAY WILL BE TEMPERATURES AND POTENTIAL CLOUD
COVER. SATELLITE IMAGERY THIS MORNING SHOWS MOSTLY CLEAR SKIES
ACROSS ALL OF NORTH TEXAS...BUT EXTENSIVE LOW CLOUDS ARE IN PLACE
ACROSS OKLAHOMA AND MUCH OF WEST TEXAS. THIS IS PRIMARILY MOISTURE
TRAPPED WITHIN THE COLD FRONTAL INVERSION. 6Z RUC FORECAST
SOUNDINGS ACROSS THE AREA INDICATE THAT THERE WILL BE SUFFICIENT
MOISTURE FOR CLOUDS TO DEVELOP AS FAR EAST AS THE METROPLEX LATER
THIS MORNING AND THERE IS ALREADY SOME SOUTHWARD DEVELOPMENT NOTED
ON SATELLITE IMAGERY OVER THE LAST FEW HOURS. FOR NOW...WILL HAVE
SOME MORNING CLOUDS IN THE FORECAST MAINLY NORTHWEST OF THE
METROPLEX BUT WILL CONTINUE TO MONITOR THROUGH THE EARLY MORNING.
IF THICKER CLOUDS DO DEVELOP FARTHER SOUTH...TEMPERATURES WOULD
REMAIN IN THE 20S AND 30S FOR MOST OF THE MORNING. OTHERWISE...
HIGHS SHOULD GENERALLY BE IN THE 40S AREAWIDE...WITH LOW TO MID
50S ACROSS OUR FAR SOUTHERN COUNTIES. WINDS WILL BECOME MORE
SOUTHERLY LATE IN THE DAY IN RESPONSE TO AN UPSTREAM SHORTWAVE
TROUGH AND WILL KEEP OVERNIGHT LOWS TONIGHT QUITE A BIT WARMER.
SHORTWAVE RIDGING WILL PASS OVER THE AREA QUICKLY DURING THE DAY
TUESDAY. WITH SOUTHERLY WINDS ESTABLISHED...TEMPERATURES WILL WARM
INTO THE LOW TO MID 60S AREAWIDE. LIMITED MOISTURE WILL BE PULLED
NORTHWARD THROUGH THE DAY TOMORROW AND MAY BE SUFFICIENT FOR A FEW
SHOWERS ALONG ANOTHER COLD FRONT TUESDAY NIGHT. RIGHT NOW WE HAVE
A 20 TO 30 PERCENT CHANCE OF SOME SHOWERS DEVELOPING MAINLY EAST
OF I-35 LATE TUESDAY NIGHT AS THE FRONT MOVES THROUGH.
WEDNESDAY SHOULD BE QUIET ACROSS THE REGION BUT ANOTHER STRONGER
SHORTWAVE WILL BE APPROACHING THE SOUTHERN PLAINS DURING THIS
TIME. A WARM FRONT ASSOCIATED WITH A DEVELOPING AREA OF LOW
PRESSURE WILL MOVE INTO NORTH TEXAS WEDNESDAY NIGHT AND THIS IS
WHEN OUR BEST CHANCES FOR RAIN APPEAR TO BE. THE BEST FORCING FOR
ASCENT WILL ARRIVE LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.
SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM ARE EXPECTED TO
DEVELOP. BEST RAIN CHANCES WILL BE EAST OF INTERSTATE 35 THROUGH
THURSDAY MORNING. A COLD FRONT WILL MOVE THROUGH THE REGION IN THE
WAKE OF THE THURSDAY SYSTEM BRINGING ANOTHER SHOT OF COOLER AIR.
HIGHS ON FRIDAY ARE EXPECT TO BE IN THE 40S AND LOWER 50S.
A QUICK WARMUP IS EXPECTED FOR THE FIRST HALF OF THE WEEKEND AS
THE UPPER PATTERN REMAINS PROGRESSIVE. SHORTWAVE RIDGING WILL
TURN LOW LEVEL WINDS SOUTHWESTERLY BY SATURDAY. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE 50S AND 60S. IF THE PATTERN REMAINS
A LITTLE MORE AMPLIFIED AS SUGGESTED BY THE ECMWF...THEN HIGHS ON
SATURDAY COULD BE MUCH WARMER THAN CURRENTLY FORECAST...WITH MID
TO UPPER 60S AREAWIDE.
DESPITE THE PROGRESSIVE UPPER PATTERN THROUGH THE UPCOMING
WEEK...AS OF NOW THERE APPEARS TO ONLY BE A FEW SMALL CHANCES FOR
RAIN DURING THIS TIME. BEYOND THE CURRENT FORECAST...THE GUIDANCE
DOES BECOME MORE AMPLIFIED ALLOWING A SYSTEM TO DIG FARTHER SOUTH
POSSIBLY INCREASING PRECIPITATION CHANCES INTO EARLY NEXT WEEK.
DUNN
&&
.AVIATION...
/ISSUED 1154 PM CST SUN JAN 17 2016/
A COLD FRONT HAS JUST MOVED THROUGH THE METROPLEX TAF SITES AND
WINDS HAVE INCREASED TO NEAR 15KT WITH HIGHER GUSTS. THESE WINDS
SHOULD DIMINISH SLIGHTLY BUT STILL AVERAGE 10-15KT THROUGH THE
NIGHT. THE WINDS WILL GRADUALLY DIMINISH DURING THE DAY MONDAY AND
POSSIBLY BECOME NEARLY CALM MONDAY AFTERNOON BEFORE EVENTUALLY
RETURNING TO THE SOUTH BY MONDAY EVENING. ONE FORECAST CONCERN IS
THE POTENTIAL FOR MVFR CIGS. MOST OF THESE CLOUDS SHOULD REMAIN
WEST OF THE TAF SITES BUT SINCE THE FRONTAL INVERSION IS VERY
SHARP AND WEAK ISENTROPIC LIFT DOES SET UP BY MORNING...WILL KEEP
A MENTION OF SCT017 IN THE TAFS DURING THE MORNING HOURS AS A
HEDGE. OUTSIDE OF THIS POSSIBILITY...VFR SHOULD PREVAIL WITH JUST
SOME HIGH CLOUDS.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 44 40 61 38 59 / 0 0 5 20 5
WACO, TX 47 41 64 42 63 / 0 0 0 10 5
PARIS, TX 42 35 55 38 56 / 0 0 10 40 5
DENTON, TX 42 38 60 35 57 / 0 0 5 20 5
MCKINNEY, TX 43 37 58 37 57 / 0 0 5 20 5
DALLAS, TX 43 40 61 39 59 / 0 0 5 20 5
TERRELL, TX 45 38 59 40 59 / 0 0 5 30 5
CORSICANA, TX 48 42 61 44 61 / 0 0 5 20 5
TEMPLE, TX 51 41 66 44 64 / 0 0 0 10 5
MINERAL WELLS, TX 44 36 63 34 61 / 0 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
214 AM CST MON JAN 18 2016
.SHORT TERM...
THE COLD FRONT THAT MOVED IN ACROSS THE SOUTH PLAINS AND ROLLING
PLAINS YESTERDAY EVENING...USHERED IN LOW CLOUDS AND AIDED IN THE
DEVELOPMENT OF PATCHY AND AREAS /AND AT TIMES LOCALLY DENSE/ FOG.
JUST FOR PROSPECTIVE...KLBB REPORTED VIS DOWN TO 5SM DUE TO FOG
WHERE AT KPVW IT WAS DOWN TO 3/4SM AT ONE POINT. MOST MODEL
SOLUTIONS SUCH AS THE HRRR AND NAM HINT AT DENSE FOG BEING MORE
PREVALENT NEAR THE TEXAS AND NEW MEXICO BORDER EARLY THIS MORNING
AND SPREADING EASTWARD TO NEAR KLBB BY LATER THIS MORNING. WITH KCVN
AND KCVS REPORTING 1/4SM...THE AFOREMENTIONED MODELS COULD HAVE A
GOOD HANDLE ON THE SITUATION. WE WILL SEE LATER ON IN THE SHIFT IF A
DENSE FREEZING FOG ADVISORY WILL BE REQUIRED. DESPITE THE STRATUS
DECK...TEMPS STILL MANAGED TO CRATER INTO THE 20S PER 08Z
METARS...WHICH SUGGESTS THIS COLD AIRMASS IS A BIT POTENT. BY MID-
LATE MORNING...THE SFC RIDGE RESPONSIBLE FOR DRIVING THE COLD FRONT
AND HENCE PROVIDING THE CAA WILL BE GRADUALLY EXITING THE REGION TO
THE EAST...WHILST SFC LEE TROUGHING BECOMES ESTABLISHED. THIS WILL
LEAD TO SFC WINDS VEERING TO THE S-SW...WHICH IS A WIND COMPONENT
FAVORABLE FOR SCOURING OUT LOW CLOUDS AND FOG. MOST AREAS WILL
THEREFORE SEE THE SUN BY AT LEAST LATE AFTN. TEMPS TODAY WILL WARM
TO AROUND SEASONAL NORMS /50S/ WITH THE EXCEPTION OF THE ROLLING
PLAINS /40S/...WHERE CLOUDS WILL BE SLOWEST TO DEPART. AN AMPLIFIED
UA RIDGE TO OUR WEST WILL BE TRANSLATING TOWARDS THE REGION
TODAY...AND FILTER IN SOME HIGH LEVEL CLOUDINESS BY THIS EVENING-
TONIGHT...MAKING FOR WARMER NIGHT /30S/.
.LONG TERM...
A MILD...DRY...AND PERIODICALLY BREEZY PATTERN SETTING UP THIS
WEEK. SPLIT PROGRESSIVE FLOW OVER THE CONUS THIS WEEK WILL BRING A
SERIES OF SHORT WAVE TROUGHS ACROSS THE PLAINS...MOST NOTABLY
TUESDAY AND AGAIN WEDNESDAY BEFORE LARGER-AMPLITUDE UPPER RIDGING
MOVES FROM THE ROCKIES TO THE PLAINS LATE WEEK INTO NEXT WEEKEND.
OVERALL...WILL FAVOR THE WARMER END OF MOS GUIDANCE...AS THAT END
HAS BEEN SUPERIOR FOR MUCH OF THE LAST SEVERAL MONTHS AND MORE
RECENTLY OVER THE LAST WEEK OR SO. PRECIP CHANCES LOOK NEAR NIL.
THE BEST CHANCE STILL APPEARS TO BE WEDNESDAY NIGHT...BUT THAT
ALSO CONTINUES TO LOOK TO BE EAST OF THE REGION. LOCAL SUPERBLEND
INITIALIZATION HAS BROUGHT SLIGHT CHANCE MENTION BACK TO THE
ROLLING PLAINS...BUT STILL CONSIDER THAT SCENARIO HIGHLY UNLIKELY
AND HAVE KEPT PRECIP MENTION OUT. TEMPS SHOULD BE AT OR ABOVE TO
WELL ABOVE CLIMATOLOGY WITH THE EXCEPTION OF THURSDAY WHEN
AMPLIFICATION OF THE UPPER FLOW WILL ALLOW SOME COLDER AIR TO
SPILL DOWN THE PLAINS. EVEN THEN...TEMPS ARE LIKELY TO ONLY BE A
FEW DEGREES OR SO BELOW NORMS. TEMPS REBOUND QUICKLY WITH THE
RIDGING MOVING OVERHEAD WITH THE WARMEST DAY OF THE WEEK LOOKING
TO BE SATURDAY WITH THE RIDGE AXIS OVERHEAD.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29/07
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1144 PM CST SUN JAN 17 2016
.AVIATION...
POOR FLYING WEATHER EXPECTED OVERNIGHT AND WELL INTO MONDAY MORNING.
LIFR CEILINGS AND VISIBILITIES EXPECTED TO PREVAIL THROUGH AROUND 17Z
MONDAY. IMPROVEMENT TO VFR EXPECTED TO OCCUR BY EARLY AFTERNOON AS
MODERATE SOUTHWEST LOW-LEVEL WINDS ARE MIXED TO THE SURFACE.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 1011 PM CST SUN JAN 17 2016/
UPDATE...PLANT INDUCED SNOW IS PRODUCING ACCUMULATING SNOWFALL NEAR
BORGER WHICH FROM LOOKS OF IT ON VIDEO AND FROM REPORTS MAY BE
APPROACHING 2" IN SOME AREAS. ISSUED A ONE COUNTY WINTER WEATHER
ADVISORY TO HANDLE THIS AS SOME DRIVERS ARE BEING SURPRISED BY
SUDDENLY HITTING LOCALIZED SNOWFALL ACCUMULATIONS ON ROADWAYS. WILL
BE INTERESTING TO SEE IF PLANTS NE OF AMA ALSO ALSO CAUSE A LOCALIZE
BAND LATER TONIGHT. OTHERWISE THE MAIN ISSUE TONIGHT IS FREEZING FOG
ACROSS THE AREA. HRRR FINALLY SEEMS TO BE HANDLING THIS POTENTIAL AND
THIS COMBINED WITH NARRE SUGGEST THE THREAT WILL MAINLY FOCUS ON THE
WRN HALF OF THE PANHANDLE. EXPANDED THE ADVISORY TO INCLUDE ALL WRN
TEXAS PANHANDLE COUNTIES. GOOD CHANCE THIS WILL HAVE TO BE EXPANDED
TO INCLUDE TEXAS COUNTY IN OK PANHANDLE AS WELL LATE TONIGHT. TEMPTED
TO PULL A FEW SE COUNTIES BASED ON HIGH RES MODELS...BUT DECIDED TO
LET IT RIDE THERE FOR NOW AS CONFIDENCE IS NOT HIGH ENOUGH TO REMOVE
COUNTIES JUST YET. OTHERWISE...JUST INCREASED CLOUD COVER TO SHOW
MOST AREAS REMAINING SOLIDLY IN STRATUS AND FOG THROUGH MONDAY
MORNING. EXPECT THIS TO BE SLOW TO ERODE...POSSIBLY LASTING MOST OF
THE MORNING ON MONDAY.
PREV DISCUSSION... /ISSUED 542 PM CST SUN JAN 17 2016/
AVIATION...EXTREMELY SHALLOW ARCTIC AIRMASS HAS PUSHED INTO THE
PANHANDLES AND IS LEADING TO VLIFR CONDITIONS WITH LOW CIGS AND
EVEN SOME FREEZING FOG IN SOUTHERN AREAS. CURRENT THINKING IS THERE
IS NO REASON FOR SIGNIFICANT IMPROVEMENT AS LOW LEVEL WINDS TURN
SOUTHERLY OVERNIGHT LIMITING POTENTIAL OF DRIER AIR TO THE NORTH
MAKING IT INTO THE AREA. WILL HOLD CIG/VSBY CLOSE TO WHAT CURRENT
OBS ARE SHOWING THROUGH MID-LATE MORNING WITH SOME DETERIORATION AT
DHT AND GUY AROUND SUNRISE. CERTAINLY SOME UNCERTAINTY IN HOW LOG IFR
CONDITIONS WILL LINGER ON MON.
PREV DISCUSSION... /ISSUED 335 PM CST SUN JAN 17 2016/
DISCUSSION...
AN ARCTIC COLD FRONT WHICH MOVED THROUGH THE PANHANDLES TODAY HAS
RESULTED IN STRONG COLD AIR ADVECTION IN ITS WAKE. THE SHALLOW COLD
AIR HAS ALSO RESULTED IN CONSIDERABLE LOW CLOUDINESS ALONG WITH
PATCHY OR AREAS OF FREEZING FOG ACROSS MUCH OF THE FORECAST AREA. HI-
RES MODELS AND LOW-RES MODELS HAVING A DIFFICULT TIME WITH THE
FREEZING FOG WHICH MAY BE DUE TO THE SHALLOWNESS OF THE COLD AIR
MASS. VISIBILITIES HAVE TANKED TO A HALF MILE OR LESS ACROSS THE
CENTRAL AND SOUTH CENTRAL TEXAS PANHANDLE AND ALSO THE SOUTHEAST
TEXAS PANHANDLE. HOISTED A FREEZING FOG ADVISORY THIS AFTERNOON
THROUGH TONIGHT WHICH EXPIRES AT 16Z MONDAY. FREEZING FOG ADVISORY
MAY NEED TO BE EXPANDED IN AREA AND MAY NEED TO BE CANCELLED EARLY
SHOULD THE FOG AND LOW CLOUDS LIFT LATER THIS EVENING OR LATE TONIGHT
OR BY MONDAY MORNING. TEMPS FALLING INTO THE TEENS AND 20S OVER MOST
OF THE AREA AND WENT WITH THE COLDER GUIDANCE FOR MINS TONIGHT.
SHALLOW COLD AIR SHOULD BE SHORT-LIVED AS LEE SURFACE TROUGH DEVELOPS
WEST OF THE PANHANDLES AND SOUTHWESTERLY SURFACE FLOW PREVAILS BY
MONDAY. WARMER AND DRY CONDITIONS EXPECTED MONDAY AND ANOTHER COLD
FRONT FORECAST TO PUSH THROUGH THE PANHANDLES TUESDAY. SLIGHTLY
COOLER BEHIND THIS FRONT TUESDAY...BUT CONTINUED NEAR OR ABOVE NORMAL
TEMPS THROUGH THE MIDDLE OF THE WEEK. MEDIUM RANGE MODELS SEEM TO
BACKING OFF SOMEWHAT ON THE WEDNESDAY NIGHT AND THURSDAY UPPER
SYSTEM. ECMWF FORECASTING SHORTWAVE TROUGH TRACKING EAST OUT OF THE
CENTRAL AND SOUTHERN ROCKIES AND INTO THE PANHANDLES BY 00Z
THURSDAY...AND THEN DEVELOPS A CLOSED UPPER LOW OVER THE CENTRAL
PLAINS STATES WEDNESDAY NIGHT. THE ECMWF BRINGS A COLD FRONT THROUGH
THE FORECAST AREA WEDNESDAY NIGHT. THE GFS FORECASTS CLOSED UPPER LOW
MOVING ACROSS THE CENTRAL PLAINS STATES BY 00Z THURSDAY AND THEN
DROPS THE CLOSED UPPER LOW SOUTHEAST INTO MISSOURI BY 18Z THURSDAY.
THE GFS BRINGS THE COLD FRONT INTO THE FORECAST AREA BY 00Z TO 06Z
THURSDAY. BOTH THE GFS AND ECMWF NOW ONLY FORECASTING A BRIEF SHOT OF
PRECIP WEDNESDAY NIGHT MAINLY OVER THE NORTHEASTERN SECTIONS OR
EASTERN SECTIONS OF THE PANHANDLES. BACKED OFF ON THE POPS AND
CONFINED POPS AND SNOW TO THE NORTHEASTERN SECTIONS OF THE FORECAST
AREA. WARMER AND DRIER AGAIN FOR LATE THIS WEEK WITH TEMPS BACK UP
ABOVE NORMAL.
SCHNEIDER
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...FREEZING FOG ADVISORY UNTIL 10 AM CST MONDAY FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF
SMITH...DONLEY...GRAY...HANSFORD...HARTLEY...HUTCHINSON...
MOORE...OLDHAM...POTTER...RANDALL...SHERMAN...WHEELER.
WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: HUTCHINSON.
OK...NONE.
&&
$$
03/06
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1011 PM CST SUN JAN 17 2016
.UPDATE...PLANT INDUCED SNOW IS PRODUCING ACCUMULATING SNOWFALL NEAR
BORGER WHICH FROM LOOKS OF IT ON VIDEO AND FROM REPORTS MAY BE
APPROACHING 2" IN SOME AREAS. ISSUED A ONE COUNTY WINTER WEATHER
ADVISORY TO HANDLE THIS AS SOME DRIVERS ARE BEING SURPRISED BY
SUDDENLY HITTING LOCALIZED SNOWFALL ACCUMULATIONS ON ROADWAYS. WILL
BE INTERESTING TO SEE IF PLANTS NE OF AMA ALSO ALSO CAUSE A LOCALIZE
BAND LATER TONIGHT. OTHERWISE THE MAIN ISSUE TONIGHT IS FREEZING FOG
ACROSS THE AREA. HRRR FINALLY SEEMS TO BE HANDLING THIS POTENTIAL AND
THIS COMBINED WITH NARRE SUGGEST THE THREAT WILL MAINLY FOCUS ON THE
WRN HALF OF THE PANHANDLE. EXPANDED THE ADVISORY TO INCLUDE ALL WRN
TEXAS PANHANDLE COUNTIES. GOOD CHANCE THIS WILL HAVE TO BE EXPANDED
TO INCLUDE TEXAS COUNTY IN OK PANHANDLE AS WELL LATE TONIGHT. TEMPTED
TO PULL A FEW SE COUNTIES BASED ON HIGH RES MODELS...BUT DECIDED TO
LET IT RIDE THERE FOR NOW AS CONFIDENCE IS NOT HIGH ENOUGH TO REMOVE
COUNTIES JUST YET. OTHERWISE...JUST INCREASED CLOUD COVER TO SHOW
MOST AREAS REMAINING SOLIDLY IN STRATUS AND FOG THROUGH MONDAY
MORNING. EXPECT THIS TO BE SLOW TO ERODE...POSSIBLY LASTING MOST OF
THE MORNING ON MONDAY.
&&
.PREV DISCUSSION... /ISSUED 542 PM CST SUN JAN 17 2016/
AVIATION...EXTREMELY SHALLOW ARCTIC AIRMASS HAS PUSHED INTO THE
PANHANDLES AND IS LEADING TO VLIFR CONDITIONS WITH LOW CIGS AND
EVEN SOME FREEZING FOG IN SOUTHERN AREAS. CURRENT THINKING IS THERE
IS NO REASON FOR SIGNIFICANT IMPROVEMENT AS LOW LEVEL WINDS TURN
SOUTHERLY OVERNIGHT LIMITING POTENTIAL OF DRIER AIR TO THE NORTH
MAKING IT INTO THE AREA. WILL HOLD CIG/VSBY CLOSE TO WHAT CURRENT
OBS ARE SHOWING THROUGH MID-LATE MORNING WITH SOME DETERIORATION AT
DHT AND GUY AROUND SUNRISE. CERTAINLY SOME UNCERTAINTY IN HOW LOG IFR
CONDITIONS WILL LINGER ON MON.
PREV DISCUSSION... /ISSUED 335 PM CST SUN JAN 17 2016/
DISCUSSION...
AN ARCTIC COLD FRONT WHICH MOVED THROUGH THE PANHANDLES TODAY HAS
RESULTED IN STRONG COLD AIR ADVECTION IN ITS WAKE. THE SHALLOW COLD
AIR HAS ALSO RESULTED IN CONSIDERABLE LOW CLOUDINESS ALONG WITH
PATCHY OR AREAS OF FREEZING FOG ACROSS MUCH OF THE FORECAST AREA. HI-
RES MODELS AND LOW-RES MODELS HAVING A DIFFICULT TIME WITH THE
FREEZING FOG WHICH MAY BE DUE TO THE SHALLOWNESS OF THE COLD AIR
MASS. VISIBILITIES HAVE TANKED TO A HALF MILE OR LESS ACROSS THE
CENTRAL AND SOUTH CENTRAL TEXAS PANHANDLE AND ALSO THE SOUTHEAST
TEXAS PANHANDLE. HOISTED A FREEZING FOG ADVISORY THIS AFTERNOON
THROUGH TONIGHT WHICH EXPIRES AT 16Z MONDAY. FREEZING FOG ADVISORY
MAY NEED TO BE EXPANDED IN AREA AND MAY NEED TO BE CANCELLED EARLY
SHOULD THE FOG AND LOW CLOUDS LIFT LATER THIS EVENING OR LATE TONIGHT
OR BY MONDAY MORNING. TEMPS FALLING INTO THE TEENS AND 20S OVER MOST
OF THE AREA AND WENT WITH THE COLDER GUIDANCE FOR MINS TONIGHT.
SHALLOW COLD AIR SHOULD BE SHORT-LIVED AS LEE SURFACE TROUGH DEVELOPS
WEST OF THE PANHANDLES AND SOUTHWESTERLY SURFACE FLOW PREVAILS BY
MONDAY. WARMER AND DRY CONDITIONS EXPECTED MONDAY AND ANOTHER COLD
FRONT FORECAST TO PUSH THROUGH THE PANHANDLES TUESDAY. SLIGHTLY
COOLER BEHIND THIS FRONT TUESDAY...BUT CONTINUED NEAR OR ABOVE NORMAL
TEMPS THROUGH THE MIDDLE OF THE WEEK. MEDIUM RANGE MODELS SEEM TO
BACKING OFF SOMEWHAT ON THE WEDNESDAY NIGHT AND THURSDAY UPPER
SYSTEM. ECMWF FORECASTING SHORTWAVE TROUGH TRACKING EAST OUT OF THE
CENTRAL AND SOUTHERN ROCKIES AND INTO THE PANHANDLES BY 00Z
THURSDAY...AND THEN DEVELOPS A CLOSED UPPER LOW OVER THE CENTRAL
PLAINS STATES WEDNESDAY NIGHT. THE ECMWF BRINGS A COLD FRONT THROUGH
THE FORECAST AREA WEDNESDAY NIGHT. THE GFS FORECASTS CLOSED UPPER LOW
MOVING ACROSS THE CENTRAL PLAINS STATES BY 00Z THURSDAY AND THEN
DROPS THE CLOSED UPPER LOW SOUTHEAST INTO MISSOURI BY 18Z THURSDAY.
THE GFS BRINGS THE COLD FRONT INTO THE FORECAST AREA BY 00Z TO 06Z
THURSDAY. BOTH THE GFS AND ECMWF NOW ONLY FORECASTING A BRIEF SHOT OF
PRECIP WEDNESDAY NIGHT MAINLY OVER THE NORTHEASTERN SECTIONS OR
EASTERN SECTIONS OF THE PANHANDLES. BACKED OFF ON THE POPS AND
CONFINED POPS AND SNOW TO THE NORTHEASTERN SECTIONS OF THE FORECAST
AREA. WARMER AND DRIER AGAIN FOR LATE THIS WEEK WITH TEMPS BACK UP
ABOVE NORMAL.
SCHNEIDER
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...FREEZING FOG ADVISORY UNTIL 10 AM CST MONDAY FOR THE FOLLOWING
ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...DALLAM...DEAF
SMITH...DONLEY...GRAY...HANSFORD...HARTLEY...HUTCHINSON...
MOORE...OLDHAM...POTTER...RANDALL...SHERMAN...WHEELER.
WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR THE FOLLOWING
ZONES: HUTCHINSON.
OK...NONE.
&&
$$
MJG
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
423 AM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
THROUGH TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER-
LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE
WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT.
DRY HIGH PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR
THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL
LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH
MOVING INTO THE FORECAST AREA. THE HRRR...ARW AND SPC WRF
INDICATE PRECIPITATION DIMINISHING AS IT MOVES INTO THE FORECAST
AREA FROM THE WEST LATE THIS AFTERNOON INTO THE EVENING. EXPECT
MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE
CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM
PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN
INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT
EXTREME NORTH TO 10 TO 20 PERCENT SOUTH. THE TOP-DOWN METHOD RUN
ON BOTH THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND SNOW
CLOSE TO THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A RAIN
AND SNOW MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED ON
THE WET BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE RIDGE.
FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA. NO
SIGNIFICANT IMPACTS ARE EXPECTED AT THIS TIME BECAUSE OF LIGHT
AMOUNTS AND MARGINAL TEMPERATURES. THE GUIDANCE TEMPERATURES ARE
LIKELY TOO HIGH TODAY BECAUSE OF A COLD START...CLOUDINESS...AND
EVAPORATIVE COOLING POTENTIAL.
MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH
THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE
LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED
A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC
WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. THE NAM MOS DID INDICATE A SMALL POP IN THE SOUTH PART LATE
TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A MID-LEVEL
SHORTWAVE TROUGH. THE GFS AND ECMWF INDICATED A LOWER POP. USED AN
AVERAGE OF THE GUIDANCE AND FORECASTED A SMALL POP IN THE SOUTH
PART. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB TEMPERATURES
ABOVE FREEZING IN THE SOUTH PART DURING THE PRECIPITATION CHANCE
TIME INDICATED BY THE NAM. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST
ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS
ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING
ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE
AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE
DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW
PRESSURE SYSTEM LIFTS NORTHEAST.
MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS
THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY
BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD
COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE
1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF
SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL
MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS
REMAINS A LOW CONFIDENCE FORECAST.
WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY
RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE
EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH MAY HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO
TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS
AFTERNOON INTO THE EVENING. THE ARW AND SPC WRF DISPLAY A
DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE
WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE.
HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR
CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR-
SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH
THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS
AFTERNOON WITH THE AXIS JUST EAST OF THE AREA. USED THE GFS LAMP
FOR THE WIND FORECAST.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
308 AM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
THROUGH TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER-
LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. A WEAK COLD
FRONT WILL MOVE INTO THE AREA LATE TONIGHT. MOISTURE WILL INCREASE
THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST. THE LOW
WILL BE NEAR THE FORECAST AREA FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR
THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL
LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH
MOVING INTO THE FORECAST AREA. THE HRRR...ARW AND SPC WRF
INDICATE PRECIPITATION DIMINISHING AS IT MOVES INTO THE FORECAST
AREA FROM THE WEST LATE THIS AFTERNOON INTO THE EVENING. EXPECT
MUCH OF THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE
CHANCE OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM
PLUS SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN
INCH OR LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT
EXTREME NORTH TO 10 TO 20 PERCENT SOUTH. THE TOP-DOWN METHOD RUN
ON BOTH THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND SNOW
CLOSE TO THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A RAIN
AND SNOW MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED ON
THE WET BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE RIDGE.
FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA. NO
SIGNIFICANT IMPACTS ARE EXPECTED AT THIS TIME BECAUSE OF LIGHT
AMOUNTS AND MARGINAL TEMPERATURES. THE GUIDANCE TEMPERATURES ARE
LIKELY TOO HIGH TODAY BECAUSE OF A COLD START...CLOUDINESS...AND
EVAPORATIVE COOLING POTENTIAL.
MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH
THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE
LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED
A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC
WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. THE NAM MOS DID INDICATE A SMALL POP IN THE SOUTH PART LATE
TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A MID-LEVEL
SHORTWAVE TROUGH. THE GFS AND ECMWF INDICATED A LOWER POP. USED AN
AVERAGE OF THE GUIDANCE AND FORECASTED A SMALL POP IN THE SOUTH
PART. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB TEMPERATURES
ABOVE FREEZING IN THE SOUTH PART DURING THE PRECIPITATION CHANCE
TIME INDICATED BY THE NAM. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
THE LOW WILL MARCH EASTWARD WITH A WARM FRONT MOVING INTO THE
AREA THURSDAY LATE MORNING WITH INCREASING CHANCES OF RAIN THROUGH
THE AFTERNOON. AS THE SYSTEM MOVES INTO THE CENTRAL GULF STATES
THURSDAY NIGHT CHANCES OF RAIN WILL CONTINUE INCREASING. THURSDAY
NIGHT THERE MAY BE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS
THE NORTH AND CENTRAL MIDLANDS. TEMPERATURES MAY BE NEAR FREEZING
ACROSS THE NORTHERN MIDLANDS. THE NAM AND ECMWF MODELS ARE COLDER
THAN THE GFS IN THE 1000 MB TO 850 THICKNESS ACROSS THE NORTH
MIDLANDS FRIDAY. SREF PRECIP TYPE PROBABILITIES FOR FREEZING RAIN
ARE MODERATELY HIGH IN THAT REGION. WILL MENTION A SLIGHT CHANCE
FREEZING RAIN FOR FRIDAY MORNING AT THIS TIME AND LOWER
TEMPERATURES FOR THURSDAY/FRIDAY TIME FRAME DUE TO POSSIBLE WEDGE
DEVELOPMENT IN THAT REGION. CONFIDENCE REMAINS LOW.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. MODELS STILL DIFFER SLIGHTLY WITH THE TRACK OF
THIS SYSTEM AND HAVE CONTINUED TO TREND TOWARD A CONSENSUS WITH
THE LOW MOVING EASTWARD THROUGH THE DAY FRIDAY AND OFFSHORE OF NC
FRIDAY NIGHT. THE SYSTEM WILL THEN TURN NORTHEASTWARD AND MOVE
ALONG THE COAST SATURDAY. AS LOW PRESSURE SYSTEM DEEPENS OFF THE
NC/VA COAST LATE FRIDAY NIGHT...PARTIAL THICKNESS SCHEMES SUGGEST
WINTRY PRECIPITATION POSSIBLE ACROSS THE NORTHERN AND WESTERN
MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH MOISTURE MAY BE
SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE REMAINED WITH THE
POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP AROUND MOISTURE.
UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND DRIER AIR WILL
RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE NEXT LOW
PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA MONDAY
NIGHT.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH MAY HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO
TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS
AFTERNOON INTO THE EVENING. THE ARW AND SPC WRF DISPLAY A
DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE
WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE.
HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR
CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR-
SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH
THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS
AFTERNOON WITH THE AXIS JUST EAST OF THE AREA. USED THE GFS LAMP
FOR THE WIND FORECAST.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
317 AM CST WED JAN 20 2016
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LIGHT SNOW ENDING BY 12 UTC.
KJB
//DISCUSSION...UPDATED 06Z...
A PERIOD OF LIGHT SNOW IS EXPECTED THROUGH JUST PRIOR TO DAYBREAK.
THE SNOW SHOULD BEGIN FALLING OVER THE EASTERN TERMINALS BY AROUND
07 UTC...WITH MAINLY 2 TO 3 SM VISBY LIKELY IN THE SNOW. HOWEVER...A
BRIEF PERIOD OR TWO OF VISIBILITIES UNDER 2 MILES IS POSSIBLE.
OTHERWISE...EXPECT MVFR CIGS TO PERSIST OVER THE AREA THROUGH AT
LEAST EARLY AFTERNOON BEFORE IMPROVING. WINDS DURING THE PERIOD WILL
REMAIN LIGHT...AROUND 5 KT OR LESS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH WITH ALL ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...MAINLY VFR. LIGHT EASTERLY WINDS.
FRIDAY...CHANCE OF LIGHT SNOW AND MVFR/IFR. BREEZY NORTHEAST
WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR. SOUTHWEST WINDS
TURNING NORTHWEST.
MDB
&&
.MARINE...
100 AM CST
SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT
WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY
FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE
SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS
AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE
UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER
NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE
LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT
ADVISORY FOR THE ILLINOIS AND INDIAN NEAR SHORES. HOWEVER...THERE
ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR SHORES DUE TO
THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO BE MONITORED
OVER THE NEXT COUPLE DAYS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
313 AM CST WED JAN 20 2016
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PERIOD OF SNOW WITH IFR VSBY OVERNIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
A PERIOD OF LIGHT SNOW IS EXPECTED THROUGH JUST PRIOR TO DAYBREAK.
THE SNOW SHOULD BEGIN FALLING OVER THE EASTERN TERMINALS BY AROUND
07 UTC...WITH MAINLY 2 TO 3 SM VISBY LIKELY IN THE SNOW. HOWEVER...A
BRIEF PERIOD OR TWO OF VISIBILITIES UNDER 2 MILES IS POSSIBLE.
OTHERWISE...EXPECT MVFR CIGS TO PERSIST OVER THE AREA THROUGH AT
LEAST EARLY AFTERNOON BEFORE IMPROVING. WINDS DURING THE PERIOD WILL
REMAIN LIGHT...AROUND 5 KT OR LESS.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH WITH SNOW AND AT LEAST INTERMITTENT IFR VSBY OVERNIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...MAINLY VFR. LIGHT EASTERLY WINDS.
FRIDAY...CHANCE OF LIGHT SNOW AND MVFR/IFR. BREEZY NORTHEAST
WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR. SOUTHWEST WINDS
TURNING NORTHWEST.
MDB
&&
.MARINE...
100 AM CST
SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT
WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY
FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE
SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS
AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE
UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER
NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE
LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT
ADVISORY FOR THE ILLINOIS AND INDIAN NEAR SHORES. HOWEVER...THERE
ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR SHORES DUE TO
THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO BE MONITORED
OVER THE NEXT COUPLE DAYS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
326 AM EST WED JAN 20 2016
.SYNOPSIS...
ISSUED AT 326 AM EST WED JAN 20 2016
LIGHT SNOW WILL OVERSPREAD THE AREA THROUGH DAYBREAK BEFORE ENDING
WEST TO EAST MID TO LATE MORNING. SNOW ACCUMULATIONS OF AN INCH OR
LESS ARE EXPECTED NORTH OF HIGHWAY 30...WITH ONE TO TWO INCHES
SOUTH. HIGHS THIS AFTERNOON WILL RANGE THROUGH THE LOW 20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM EST WED JAN 20 2016
VIGOROUS NRN STREAM SW DROPPING SEWD THROUGH WRN WI ATTM WILL
MINOR OUT ACRS THE ERN LAKES TONIGHT. LL MSTR FLUX AHD OF THIS SYS
WANES W/NWD EXTENT INTO THE TEETH OF ERODING ARCTIC DOME AND
DELAYING TOP DOWN SATURATION TIMED W/STRONGEST MID LVL BASED
FORCING. HWVR -SN WILL OVERSPREAD MOST AREAS THROUGH
DAYBREAK...ALTHOUGH AMTS XPCD TO REMAIN TRIVIAL OWING TO WANING
MID LVL ASCENT AND OVERALL BRIEF DURATION (INCH OR LESS NORTH OF
30 AND 1-2 INCHES SOUTH) AND OF LTL CONCERN IN LIGHT OF GENERAL
MID TEEN SFC TEMPS. OTRWS SFC RIDGING TO REDVLP IN WAKE OF THIS
SYS OVERNIGHT HWVR CLDS XPCD TO PERSIST UNDERNEATH GROWING
SUBSIDENCE INDUCED THERMAL INVERSION.
&&
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 326 AM EST WED JAN 20 2016
QUIET/SEASONAL WX AND GRADUAL MODERATION ANTICIPATED THURSDAY-
SUNDAY...WITH NEXT DECENT OPPORTUNITY FOR PRECIPITATION EARLY NEXT
WEEK...
PROGRESSIVE FLOW PATTERN WILL PERSIST ALOFT THROUGH THE LONG TERM AS
SEVERAL UPPER LEVEL TROUGHS CREST WEST COAST RIDGE INTO
DOWNSTREAM/BROAD EASTERN CONUS TROUGH. FIRST DIGGING SHORTWAVE STILL
ON TARGET TO CLOSE OFF AND TAKE A MORE SOUTHERLY ROUTE THROUGH THE
SOUTHEAST US/MID ATLANTIC FRIDAY INTO SATURDAY. DEFORMATION PRECIP
SHIELD ON NORTHERN FRINGE WILL LIKELY PASS SOUTH AND EAST OF THE
LOCAL AREA...ALTHOUGH CLOUD CANOPY AND TIGHTENING LOW LEVEL HEIGHT
GRADIENT (INCREASING ENE FLOW) WILL STILL MAKE FOR A SOMEWHAT RAW
FRIDAY-EARLY SATURDAY. CLOUDS SHOULD SCOUR OUT WITH SOME WARMING
INTO SUNDAY AS RIDGING THROUGH THE COLUMN FOLDS IN. THE NEXT UPPER
TROUGH AND POTENTIAL FRONTAL WAVE DEVELOPMENT WILL PROVIDE THE NEXT
CHANCE FOR SNOW AND RAIN BY EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1243 AM EST WED JAN 20 2016
UPSTREAM CONDS ACRS NRN IL QUITE TELLING THIS MORNING AND CONFIRM
LATEST RAP TIME-HEIGHT CROSS SECTIONS INDICATING A SLOW TOP DOWN
SATURATION TAKING PLACE. THUS NO CHOICE BUT TO FOLLOW DAMPENED
RAP/HRRR BLEND W/ONSET OF -SN LTR THIS MORNING. BRIEF PD OF MVFR
RESTRICTION PSBL TIMED W/FINAL SATURATION/WANING ASCENT OVERLAP
YET XPC AN INCH OR LESS AT BOTH TERMINALS. LWR BOUND MVFR CIGS TO
PERSIST INTO AFTN BFR IMPROVING AS SFC TROUGH PASSES THROUGH ALG
W/INCREASING SUBSIDENCE YIELDING VFR CONDS LT PD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$FISHER
SYNOPSIS...T
SHORT TERM...T
LONG TERM...STEINWEDEL
AVIATION...T
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1249 AM EST WED JAN 20 2016
.SYNOPSIS...
ISSUED AT 315 PM EST TUE JAN 19 2016
CLOUDS WILL INCREASE LATER THIS EVENING AHEAD OF A WEAK SYSTEM
THAT WILL SPREAD LIGHT SNOW ACROSS THE REGION LATE TONIGHT AND
WEDNESDAY MORNING. SNOW ACCUMULATIONS SHOULD BE UNDER TWO INCHES
WITH MANY LOCATIONS ONLY SEEING AN INCH OR LESS. TEMPERATURES
WILL SLOWLY WARM OVER THE NEXT SEVERAL DAYS...HEADING BACK TOWARDS
FREEZING BY THE WEEKEND.
&&
.UPDATE...
ISSUED AT 826 PM EST TUE JAN 19 2016
MAIN GRID ADJUSTMENT THIS EVE WAS TO LOWER MINS SEVERAL DEGREES
ACROSS NWRN PORTION OF CWA WHERE LIGHT WINDS AND FRESH SNOW COVER
WERE RESULTING IN A PERIOD OF STRONG RADIATIONAL COOLING. OTRWS
SLOWED TIMING OF APCHG SNOW SHIELD SLIGHTLY... BUT ACCUMS STILL
LOOK GOOD AND LIGHT SNOW STILL EXPECTED ACROSS MOST IF NOT ALL OF
THE CWA DURING THE MORNING COMMUTE TIME WED.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 313 PM EST TUE JAN 19 2016
SW FLOW AHEAD OF THE NEXT SYSTEM HAS PUSHED LAKE EFFECT THREAT
NORTH OF THE AREA. HIGH CLOUDS WERE STREAMING EASTWARD WITH AN
AREA OF LIGHT SNOW EXTENDING FROM NORTHERN IOWA TO WEST OF ST
LOUIS. MODELS HAVE TRENDED SOMEWHAT FASTER WITH ARRIVAL OF PRECIP
BUT WITH DRY AIRMASS IN PLACE THINK THEY HAVE GOTTEN CARRIED AWAY
WITH TIMING (6Z ONSET IN FAR SW). DID A GENERAL AVERAGE OF RUC
POPS AND PREVIOUS FORECAST TO TRY TO NUDGE UPWARD WITH ONSET BUT
KEEP REASONABLE. CONCERNS WITH REGARDS TO NORTHERN EXTENT OF
SNOWFALL AS MAIN FORCING REMAINS US 30 AND SOUTH WITH SFC LOW
PASSING WELL SOUTH OF THE AREA. RADAR TRENDS ACROSS N IOWA SEEM TO
BE WEAKENING AS WELL LEADING TO INCREASING CONCERN.
WITH REGARDS TO QPF/SNOW AMOUNTS...LARGE DENDRITIC GROWTH ZONE WILL
ARRIVE AT THE PEAK WITH A DEPTH OF MORE THAN 10,000 FT. THIS DEPTH
WILL BE NEEDED TO HELP MAKE UP FOR THE LACK OF SATURATION IN THE
SAME LAYER AND ONLY WEAK LIFT. ALL THESE FACTORS LEAD TO A
CONTINUATION OF LOW ACCUMULATIONS WITH LESS THAN AN INCH NORTH OF US
30 AND MAYBE UP TO AN INCH AND HALF SOUTH. WOULD NOT BE SURPRISED TO
SEE MICHIGAN COUNTIES GET LITTLE MORE THAN A FEW TENTHS OF AN INCH.
EVEN WITH THE LIGHT AMOUNTS...THERE MAY BE SOME MORNING TRAVEL
ISSUES GIVEN TIMING OF THE EVENT AND TENDENCIES FOR THESE LIGHT
EVENTS TO CAUSE MORE HEADACHES THAN SOME OF THE BIGGER ONES.
LOOKS LIKE SNOW SHOULD TRANSITION QUICKLY WEST TO EAST...POSSIBLY
BEGINNING TO EXIT THE AREA BY 12Z WEDS IN THE FAR WEST AND GONE BY
18Z EAST. HAVE MADE ONLY MINOR CHANGES TO PREVIOUS FORECAST BEYOND
12Z WITH TIMING ISSUES.
&&
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 313 PM EST TUE JAN 19 2016
OVERALL A QUIET LONG TERM PERIOD FOR MID JANUARY BUT A COUPLE
SYSTEMS TO WATCH.
HIGH PRESSURE WILL BE MOVING IN TO START THE PERIOD WEDNESDAY NIGHT.
WINDS WILL BECOME LIGHT OR CALM AS ANTICYCLONE CENTER DRIFTS INTO
THE AREA OVERNIGHT. WITH CLEARING SKIES AND LIGHT WINDS SHOULD SEE A
GOOD RADIATIONAL RESPONSE. HAVE LOWERED TEMPS A FEW DEGREES TOWARDS
THE LOWER END OF MOS. WOULD BE TEMPTED TO LOWER FURTHER IF MORE
SNOWFALL WAS EXPECTED WEDNESDAY. LIGHT ACCUMS ALONG WITH DEPARTING
COLD POCKET AND WARM AIR ADVECTION ALOFT PRECLUDES ANY ADDITIONAL
LOWERING AT THIS TIME.
NEXT FOCUS IS WITH STRONG CYCLOGENESIS EXPECTED TO TAKE PLACE FROM
THE MID SOUTH TO THE ATLANTIC COAST REGION FRIDAY INTO SATURDAY AS
SPLIT FLOW PHASES AND ENERGY TRANSFERS TO COASTAL LOW DEVELOPMENT.
NORTHERN STREAM SHORT WAVE RESPONSIBLE FOR INFUSING THIS SYSTEM WILL
DROP ACROSS OUR AREA FRIDAY. MODELS STILL HAVE DIFFERENCES ON WHERE
PERTINENT UPPER AIR FEATURES AND SFC LOW WILL TRACK BUT DEEPENING
SYSTEM WILL AID IN INCREASING EAST TO NORTHEAST LOW LEVEL FLOW
LOCALLY WHICH IN TANDEM WITH PASSING SHORT WAVE SHOULD HELP PULL
COLDER AIR AND MORE CLOUDS INTO THE FORECAST AREA FRIDAY. PCPN
CHANCES LOOK SMALL WITH MOISTURE STARVED SHORT WAVE THAT QUICKLY
GETS ABSORBED INTO SOUTHERN WAVE SO KEPT FORECAST DRY DESPITE THE
INCREASING MID LEVEL MOISTURE AND LOW LEVEL COLD AIR ADVECTION. ONCE
SYSTEM WRAPS AND DEEPENS WE WILL SEE SUBSIDENCE WITH INCREASING
SHORT WAVE RIDGING WITH CLEARING SKIES AND MODERATING TEMPS FOR
SATURDAY. AS WITH PREVIOUS SHIFT DID ALLOW A LOW CHANCE FOR LIGHT
SNOW TO CONTINUE IN THE FAR SOUTHEAST WITH ANY NORTHWARD ADJUSTMENT
STILL POSSIBLE.
NEXT DECENT CHANCE FOR PCPN LOCALLY WILL BE MONDAY OR TUESDAY WITH
WHAT APPEARS TO BE A COMPLICATED PARTIALLY PHASED SYSTEM. GFS ON THE
FASTER SIDE WHILE 12Z ECMWF SLOWER WITH MORE PCPN TUESDAY.
EXPECT ADDITIONAL CHANGES IN MODELS SO FEW CHANGES MADE AND
GENERALLY STAYED WITH INHERITED LOW CHANCE POPS FOR THE ENTIRE
PERIOD. COULD STILL BE A RAIN OR SNOW EVENT AS WELL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1243 AM EST WED JAN 20 2016
UPSTREAM CONDS ACRS NRN IL QUITE TELLING THIS MORNING AND CONFIRM
LATEST RAP TIME-HEIGHT CROSS SECTIONS INDICATING A SLOW TOP DOWN
SATURATION TAKING PLACE. THUS NO CHOICE BUT TO FOLLOW DAMPENED
RAP/HRRR BLEND W/ONSET OF -SN LTR THIS MORNING. BRIEF PD OF MVFR
RESTRICTION PSBL TIMED W/FINAL SATURATION/WANING ASCENT OVERLAP
YET XPC AN INCH OR LESS AT BOTH TERMINALS. LWR BOUND MVFR CIGS TO
PERSIST INTO AFTN BFR IMPROVING AS SFC TROUGH PASSES THROUGH ALG
W/INCREASING SUBSIDENCE YIELDING VFR CONDS LT PD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...JT
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...LASHLEY
AVIATION...T
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1138 PM CST TUE JAN 19 2016
...AVIATION UPDATE...
.SYNOPSIS...
ISSUED AT 243 PM CST TUE JAN 19 2016
A SHRTWV TROF ADVECTING THROUGH NW FLOW LEAD TO SNOW ACROSS THE
IOWA AND N MO THIS AFTERNOON. SNOWFALL TOTALS OF 1 TO 4 INCHES
HAVE BEEN REPORTED IN SW IA INTO S CENTRAL IA. THIS FEATURE WILL
MOVE TO THE EAST THROUGH THE REST OF TODAY. AS THE COLUMN BEGINS
TO SATURATE...SNOW WILL OVERSPREAD THE CWA THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 243 PM CST TUE JAN 19 2016
MAIN FORECAST CONCERN FOR THE SHORT TERM IS THE SNOW THIS
AFTERNOON AND INTO THE EVENING. GUIDANCE AND OBSERVATIONAL TRENDS
SUGGESTS THAT HEAVIEST SNOW...4+ INCHES...WILL OCCUR JUST TO THE
SOUTH OF THE CWA. AS A RESULT...UPDATED SNOW TOTALS AND CURRENT
CHANGES TO THE FORECAST WILL RESULT IN THE ADDITION OF MCDONOUGH
COUNTY IN THE WS.Y. THE BEST CHANCE FOR 3+ INCHES WILL BE SOUTH OF
A LINE FROM MACOMB TO KEOSAUQUA.
HIRES GUIDANCE....SPECIFICALLY THE HRRR AND HIRES NMM KEEPS THE
HEAVIEST SNOW TO OUR SOUTH THIS EVENING. THIS LINES UP WITH AN
OMEGA SIGNAL IN THE DGZ AS WELL. IT APPEARS THAT LIGHT SNOW WILL
OVERSPREAD THE AREA FROM WEST TO EAST. NEAR 00Z...AS THE OMEGA
INCREASES ACROSS THE SOUTH...SNOW INTENSITY SHOULD PICK UP. AT
THIS TIME...THE VORT WILL BE QUICKLY MOVING THROUGH LEADING TO A
QUICK END TO THE SNOW FROM WEST TO EAST. THINK THAT MOST OF THE
SNOW WILL BE OVER AOA 06Z WED. A LOOK AT THE FORECAST PLUMES
SUGGESTS THAT THE HIGHEST CONFIDENCE FOR 3+ INCHES WILL BE ACROSS
OUR EXTREME SOUTH. SNOW TOTALS SHOULD RAPIDLY DECREASE AS YOU
MOVE NORTH OF HWY 34 CORRIDOR WITH THE QC SEEING AROUND AN INCH
TOTAL. THIS IS SUPPORTED BY THE HIRES GUIDANCE AND ENSEMBLE
OUTPUT.
PAST THIS..IT LOOKS LIKE SOME OF THE WARMEST TEMPS IN THE PAST
COUPLE OF DAYS WILL BE TOMORROW WITH NO CHANCE OF POPS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 243 PM CST TUE JAN 19 2016
QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA WEDNESDAY
NIGHT THROUGH THURSDAY AS HIGH PRESSURE QUICKLY MOVES THROUGH THE
AREA. TEMPERATURES WILL AVERAGE BELOW NORMAL.
ON THURSDAY NIGHT...MAINLY DRY CONDITIONS ARE EXPECTED AS THE HIGH
MOVES INTO THE OHIO VALLEY. A WEAK DISTURBANCE MOVING THROUGH THE
UPPER MIDWEST MAY BRING SOME FLURRIES OR VERY LIGHT SNOW TO THE
HIGHWAY 20 CORRIDOR WEST OF DUBUQUE.
DRY CONDITIONS WILL THEN BE SEEN ACROSS THE AREA ON FRIDAY AS
ANOTHER HIGH PRESSURE BUILDS INTO THE MIDWEST. TEMPERATURES WILL BE
SLIGHTLY BELOW NORMAL.
FRIDAY NIGHT ON...
THE MODEL CONSENSUS HAS DRY CONDITIONS FRIDAY NIGHT THROUGH SUNDAY
AS HIGH PRESSURE MOVES INTO THE OHIO VALLEY. TEMPERATURES WILL
SLOWLY CLIMB TO ABOVE NORMAL ON SUNDAY. ATTENTION THEN TURNS TO A
POTENTIAL STORM SYSTEM.
SUNDAY NIGHT INTO MONDAY THE MODELS DIVERGE ON THEIR RESPECTIVE
SOLUTIONS. THE ECMWF IS DRY BUT THE GEM AND TO A MUCH LESSER EXTENT
THE GFS SUGGEST A WEAK STORM SYSTEM MOVING THROUGH THE AREA. GIVEN
THE CONSIDERABLE DIFFERENCES...THE MODEL CONSENSUS HAS SLIGHT CHANCE
POPS FOR SUNDAY NIGHT AND MONDAY.
MONDAY NIGHT AND TUESDAY THE MODEL CONSENSUS HAS DRY CONDITIONS AS
HIGH PRESSURE BUILDS INTO THE MIDWEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1134 PM CST TUE JAN 19 2016
LIGHT SNOW WILL END...OR DIMINISH TO NON ACCUMULATING FLURRIES
BETWEEN 05Z AND 07Z THIS EVENING. AS THE SNOW ENDS...MVFR CIGS
WILL LIFT TO VFR FOR A SHORT PERIOD...BEFORE LIKELY DROPPING TO
THE 600 TO 1500 FT RANGE FOR THE EARLY MORNING THROUGH MID MORNING
HOURS WEDNESDAY. THIS WILL BE DUE TO SATURATED LOW LEVELS IN THE
WAKE OF THE EVENING SNOW EVENT AND PERSISTENT LIGHT SOUTHEAST
WIND. I WILL SHOW SOME MODEST IMPROVEMENT DURING THE DAY
WEDNESDAY...BUT DO NOT EXPECT WIDESPREAD VFR THROUGH THE PERIOD.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LEE-VAN
BUREN.
IL...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR HANCOCK-
MCDONOUGH.
MO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARK-
SCOTLAND.
&&
$$
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...08
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
239 AM MST WED JAN 20 2016
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 237 AM MST WED JAN 20 2016
LATEST SATELLITE IMAGERY AND UPPER AIR ANALYSIS SHOWS SEMI ZONAL
FLOW OVER THE CONUS. A LONG BAND OF CLOUD COVER WAS EVIDENT OVER
THE ROCKIES AHEAD OF A SHORT WAVE TROUGH. LOW CLOUDS AND FOG WERE
MOVING NORTH OVER THE TRI-STATE AREA DUE TO INCREASED MOISTURE
ADVECTION FROM THE LOW LEVEL JET. LATEST OBSERVATIONS SHOW
VISIBILITIES UNDER A MILE BEING REPORTED SPORADICALLY UNDER THE LOW
CLOUDS.
TODAY EXPECT THE FOG AND LOW CLOUDS TO PROGRESS NORTHWARD ACROSS THE
ENTIRE AREA. THE WORST OF THE FOG WILL BE EAST OF THE COLORADO
BORDER...WITH THE LOWEST VISIBILITIES OCCURRING DURING THE FIRST
HALF OF THE MORNING. DUE TO CLOUDS REMAINING OVER THE AREA THROUGH
THE DAY...THE FOG MAY LINGER A BIT LONGER THAN NORMAL. LOCATIONS
WHERE VISIBILITIES ARE UNDER A MILE WILL LIKELY HAVE A THIN GLAZE OF
ICE DEVELOP ON EXPOSED SURFACES.
OTHERWISE AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA
TODAY. DUE TO THE WEAK LIFT AND MOST OF THE MOISTURE REMAINING
ABOVE 700MB...DO NOT ANTICIPATE ANY PRECIPITATION OCCURRING DURING
THE DAY.
TONIGHT A SECOND UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE
AREA...CLOSING OFF FROM THE REST OF THE UPPER LEVEL FLOW OVER THE
NORTHEAST HALF OF THE AREA. THE MAJORITY OF THE VORTICITY WILL BE
WITH THE FIRST SHORT WAVE TROUGH...AHEAD OF THIS SECOND ONE. THIS
WILL LEAD TO LITTLE OR NO MID/UPPER LEVEL LIFT WITH THIS TROUGH AS
IT MOVES THROUGH. HOWEVER WEAK LOW LEVEL FRONTOGENESIS...IN THE
FIRST KILOMETER ABOVE GROUND WHERE THE ENVIRONMENT WILL BE
SATURATED...WILL LEAD TO SOME SNOW DEVELOPING AFTER MIDNIGHT OVER
THE NORTHEAST QUADRANT OF THE AREA. THIS AREA OF SNOWFALL WILL
GRADUALLY MOVE EAST WITH THE PARENT TROUGH.
MEANWHILE ANOTHER AREA OF LIFT/LOW LEVEL FRONTOGENESIS WILL DEVELOP
OVER THE NORTHWEST QUADRANT OF THE AREA BEHIND THE CLOSED LOW. THE
FRONTOGENESIS IN THIS PART OF THE AREA IS STRONGER THAN TO THE EAST
AND THE WEAK LIFT WITH IT IS DEEPER. IN ADDITION THE HIGH-RESOLUTION
MODELS ARE INDICATING A BETTER SHOT OF SNOW DEVELOPING THERE THAN
OVER THE EAST. WITH THIS IN MIND WILL HAVE THE BETTER CHANCES FOR
SNOWFALL OVER THE NORTHWEST PART OF THE AREA.
A COLD FRONT WILL ALSO MOVE THROUGH THE AREA WITH THE SECOND UPPER
LEVEL TROUGH AND AHEAD OF THE SNOWFALL. BEHIND THE FRONT WINDS WILL
INCREASE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 237 AM MST WED JAN 20 2016
THURSDAY MORNING THE LIGHT SNOW WILL CONTINUE OVER BOTH THE
NORTHEAST AND NORTHWEST QUADRANTS OF THE AREA...GRADUALLY MOVING
EAST THROUGH THE MORNING. BY THE EARLY AFTERNOON THE WEAK LIFT WILL
END CAUSING ANY LINGERING SNOW TO END AS WELL. TOTAL SNOWFALL FOR
TONIGHT AND THURSDAY WILL BE LESS THAN AN INCH.
IN ADDITION TO THE SNOW NORTH WINDS WILL BE WINDY...WITH GUSTS UP TO
40 MPH OVER THE WEST HALF OF THE AREA. TO THE EAST THE WINDS WILL
NOT BE AS STRONG DUE TO A WEAKER LOW LEVEL JET OVERHEAD. THE WINDS
WILL LEAD TO BLOWING SNOW WHICH MAY REDUCE VISIBILITIES SOME.
THE BLOWING SNOW WILL END DURING THE AFTERNOON. BEHIND THE SNOW
CLOUDS WILL BEGIN TO CLEAR AS DRIER AIR MOVES INTO THE AREA FROM THE
WEST.
THURSDAY NIGHT WINDS WILL QUICKLY DECLINE DURING THE EVENING.
MEANWHILE CLOUDS WILL CONTINUE TO CLEAR FROM WEST TO EAST. WITH A
COOLER AIR MASS IN PLACE TEMPERATURES WILL FALL INTO THE TEENS.
THIS WILL LEAD TO WIND CHILLS IN THE SINGLE DIGITS BY SUNRISE.
FRIDAY/FRIDAY NIGHT WILL BE UNEVENTFUL AS DRIER AIR REMAINS IN PLACE
AS A LONG WAVE RIDGE MOVES OVERHEAD. TEMPERATURES WILL WARM TO NEAR
NORMAL.
SATURDAY...UPPER RIDGE AXIS MOVES OVER THE AREA DURING THE DAY
AHEAD OF A BROAD UPPER TROUGH WHOSE AXIS MOVES ASHORE BY SUNSET.
FLOW ALOFT SHIFTS TO THE SOUTHWEST AS A RESULT AND CONTINUES THROUGH
THE NIGHT. SOME HIGH CLOUDINESS EXPECTED DURING THE DAY...DECREASING
SOME OVERNIGHT. NO PRECIPITATION EXPECTED. AFTERNOON
TEMPERATURES PEAK IN THE MID 40S TO MID 50S (EAST TO WEST) WITH
OVERNIGHT LOWS IN THE LOW TO MID 20S.
SUNDAY...LONG RANGE MODELS IN BETTER AGREEMENT (COMPARED TO 24 HOURS
AGO) BRINGING BASE OF UPPER TROUGH INTO THE AREA BY DAYS END THEN
INTO THE MIDWEST OVERNIGHT. COLD FRONT MOVES THROUGH AS WELL WITH
NORTHERLY SURFACE WINDS. MODELS DISAGREE ON EXTENT OF COLD AIR WITH
THE ECMWF SEVERAL DEGREES COLDER AT 850MB WHEN COMPARED TO THE GFS.
CURRENT FORECAST HIGHS IN THE MID TO UPPER 40S WOULD FAVOR THE GFS
SOLUTION. NORTH WINDS CONTINUE OVERNIGHT WITH LOW TEMPERATURES IN
THE LOW TO MID 20S. AS FAR AS PRECIPITATION CHANCES...WILL KEEP SOME
SLIGHT CHANCE POPS GOING FOR THE DAY...INCREASING JUST A BIT
OVERNIGHT.
MONDAY...SUNDAYS WEATHER SYSTEM MOVES AWAY FROM THE AREA BUT THE
FORECAST AREA IS CAUGHT IN NORTHWEST FLOW ALOFT ALLOWING MORE
WEATHER SYSTEMS TO MOVE INTO THE AREA. CURRENTLY HAVE A DRY FORECAST
BUT WOULDNT BE SURPRISED IF WE HAVE SOME SPOTTY LIGHT PRECIP. MAY
SEE BREEZY NORTHWEST WINDS DURING THE DAY AS WELL. AFTERNOON
TEMPERATURES A BIT COOLER AND JUST BELOW NORMAL WITH UPPER 30S TO
LOW 40S. LOOKING AT SOME DECREASING CLOUDINESS OVERNIGHT WITH LOW
TEMPERATURES IN THE MID TEENS TO LOW 20S.
TUESDAY...SUNSHINE RETURNS TO THE AREA AS HIGH AMPLITUDE RIDGE AXIS
MOVES SLOWLY TOWARD THE AREA DURING THE DAY. RIDGE AXIS BREAKS DOWN
PRETTY QUICKLY OVERNIGHT WITH SOME INCREASE IN HIGH CLOUDS EXPECTED.
AFTERNOON TEMPERATURES WARM BACK INTO THE LOW TO MID 40S WITH
OVERNIGHT LOWS AGAIN IN THE MID TEENS TO LOW 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1023 PM MST TUE JAN 19 2016
VFR CONDITIONS WILL CONTINUE BRIEFLY AT KGLD AND KMCK AND THEN
DETERIORATE TO MVFR AND LOWER, ESPECIALLY AT KMCK. THE HRRR KEEPS
KGLD AT VFR WHILE THE NAM BRINGS SOME LOWER CONDITIONS. CONDITIONS
SHOULD IMPROVE RATHER EARLY WEDNESDAY MORNING EVEN AT KMCK. SOME
MID LEVEL CLOUDS REMAIN IN RESPONSE TO THE NEXT SHORTWAVE THAT
COMES THROUGH WEDNESDAY AFTERNOON. CLOUDS DECREASE BRIEFLY
WEDNESDAY EVENING IN A BRIEF LULL BEFORE THE NEXT SHORTWAVE
AFFECTS THE AREA.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...99/JTL
AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1038 PM MST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 210 PM MST TUE JAN 19 2016
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS RIDGING ACROSS THE
ROCKIES WITH A SHORTWAVE TROUGH TRANSITIONING OUT OF THE PLAINS
TOWARDS THE CENTRAL MISSISSIPPI RIVER VALLEY. ANOTHER SHORTWAVE
TROUGH UPSTREAM OF THE RIDGE IS MOVING INTO THE PACIFIC NORTHWEST
WITH A MUCH STRONGER WEST-EAST ORIENTATED UPPER LEVEL JET OVER
NORTHERN CALIFORNIA. AT THE SURFACE LEE TROUGH HAS DEVELOPED OVER
EAST CENTRAL COLORADO (NEAR FRONT RANGE) AND WARM FRONT IS IN THE
PROCESS OF LIFTING OVER THE NORTHEAST PART OF OUR CWA (FROM KMCK TO
KHLC). PERSISTENT STRATUS IS STILL IN PLACE IN OUR EASTERN CWA WITH
CLOUD SHIELD BREAKING UP IN THE WEST.
THIS EVENING-WEDNESDAY MORNING...MAIN CONCERN WILL FOCUS ON POSSIBLE
DENSE FOG DEVELOPMENT THIS EVENING/OVERNIGHT. MODELS SUPPORT LEE
TROUGH SHIFTING EASTWARD WITH SOUTHERLY FLOW QUICKLY DEVELOPING
AFTER SUNSET. THIS SHOULD HELP ADVECT GOOD BL MOISTURE BACK INTO OUR
CWA AND STRATUS IN THE EAST COULD THEN EXPAND WESTWARD. EARLIER
HRRR/RAP SUPPORTED FOG REDEVELOPING AFTER 00Z THIS EVENING NEAR THE
CO/KS BORDER AND SPREADING EASTWARD. LATEST SREF/NAM/RAP/HRRR NOW
SHOWING STRONGER SIGNAL AFTER MIDNIGHT TONIGHT THROUGH EARLY
WEDNESDAY MORNING WITH MAIN FOG AXIS SHIFTED FURTHER EAST (TOWARD
BACK EDGE OF CURRENT STRATUS DECK). I KEPT FOG COVERAGE/TIMING
SIMILAR TO EARLY GUIDANCE COVER POSSIBILITY...HOWEVER CONFIDENCE AT
THIS POINT IS SIGNIFICANTLY LOWER ON WHERE OR IF DENSE FOG MAY
DEVELOP OVER OUR CWA. (FOG MAY BE A GOOD BET BUT DENSE FOG MAY BE
PATCHY).
WEDNESDAY...TWO SHORTWAVES ARE EXPECTED TO MOVE ACROSS THE ROCKIES
AND OVER OUR CWA WITH THE FIRST (WEAKER) SHORTWAVE MOVING OVER OUR
CWA MIDDAY WEDNESDAY. AS WAS INDICATED IN EARLIER GUIDANCE ON MID
SHIFT THERE IS A SIGNIFICANT DRY LAYER FROM ABOVE THE BL TO 600-
700MB. DESPITE FORCING THIS LOWERS CONFIDENCE IN ANY MEASURABLE
PRECIP DURING THE DAY WEDNESDAY. BY LATE WEDNESDAY AFTERNOON THE
SECOND (STRONGER) SHORTWAVE TROUGH DIGS SOUTHEAST AND OVERTAKES THE
FIRST TROUGH WITH A STRONGER UPPER LEVEL JET BEGINNING TO DEVELOP.
BY LATE AFTERNOON THERE IS A WEAK PRECIP SIGNAL IN OUR FAR EASTERN
CWA AND GUIDANCE THERE DOES SHOW SOME MOISTENING OF THE MOISTURE
PROFILE. I KEPT SMALL AREA OF SLIGHT CHANCE POPS IN GRAHAM/NORTON
COUNTIES TO MATCH THIS...BUT CONFIDENCE IS STILL NOT HIGH THAT
THINGS WOULD START THIS EARLY.
OTHER CONCERN FOR WEDNESDAY WILL BE HIGHS. POTENTIAL EXISTS AGAIN
FOR LINGERING STRATUS...HOWEVER WITH TROUGHS MOVING THROUGH THE
REGION THICK/OPAQUE MID-HIGH CLOUD COVER COULD ALSO LIMIT DIURNAL
HEATING. I LOWERED HIGHS IN THE EAST FROM PREVIOUS FORECAST DUE TO
POTENTIAL IMPACTS OF CLOUD COVER. TOUGH CALL AND IF WE WERE TO
CLEAR OUT (MORE LIKELY IN THE WEST) WE COULD SEE HIGHS IN THE
UPPER 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 248 PM MST TUE JAN 19 2016
FORECAST ISSUES WILL BE CHANCE OF PRECIPITATION AND PHASE OF
PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY. SATELLITE SHOWING A
SOMEWHAT AMPLIFIED BUT STILL PROGRESSIVE AND ACTIVE FLOW PATTERN
FROM THE PACIFIC INTO THE WESTERN ATLANTIC. LARGE AND COMPLICATED
UPPER TROUGH IS OVER THE NORTHEAST PACIFIC.
AT JET LEVEL...THE MODELS WERE HAVING A LITTLE TROUBLE WITH THE JET
ALONG THE WEST COAST. AT MID LEVELS...MODELS WERE ALL ABOUT THE SAME
BUT THEY WERE ALSO A LITTLE FAR EAST/FAST WITH THE UPPER TROUGH NOW
COMING ON THE COAST. THE NAM/ECMWF WAS DOING THE BEST ON THE SURFACE
WIND AND PRESSURE FIELD. THE GFS AND CANADIAN WERE DOING THE BEST ON
THE LOW LEVEL THERMAL FIELD WITH MOST MODELS NOT BEING COLD ENOUGH.
WEDNESDAY NIGHT...DEVELOPING PRECIPITATION EVENT IS IN ITS BEGINNING
STAGES. MODELS DIFFERENT ON SPEED...POSITION AND AMPLITUDE OF MID
LEVEL CIRCULATION THAT APPEARS TO BE DEVELOPING ON TOP OF US OR JUST
TO THE EAST OF US. TODAYS MODEL RUNS VERY DIFFERENT THAN 24 HOURS
AGO. BY THE BEGINNING OF THIS PERIOD...MODELS STILL HAVE STRONG
NORTH TO SOUTH JET ON THE WEST SIDE OF THIS UPPER SYSTEM.
THIS COMBINED WITH THE PROBLEM OF THE MODELS INITIALLY HAVING THIS
SYSTEM TOO FAR EAST THIS MORNING...LEADS ME TO BELIEVE THAT WHATEVER
ENDS UP BEING THE SLOWER AND EVEN FURTHER SOUTH SOLUTION WILL END UP
BEING MORE RIGHT. EVEN NOW AM THINKING CURRENT MODEL RUN STILL MAY
BE TOO FAST/FAR NORTH. TROUGH IS ELONGATED AND COMPROMISED OF A
NORTHERN AND SOUTHERN CIRCULATIONS WITHIN THIS TROUGH. PAST
EXPERIENCE HAS SHOWN THIS SETUP IS NOT GREAT FOR A LOT OF
PRECIPITATION.
SAYING ALL THAT...THE FAR EASTERN PORTION OF THE AREA WILL HAVE THE
BEST CHANCE WITH BEST CHANCE OVERALL AT THIS TIME BEING TO THE EAST
OF OUR AREA. THE GRADIENT OF THE CHANCE OF PRECIPITATION WILL BE
REALLY SHARP. PER THE REASONING ABOVE...AM THINKING THAT THE BEST
CHANCE OF PRECIPITATION WILL BE AFTER MIDNIGHT AND THAT IS SUPPORTED
BY THE SREF PROBABILITIES. BEST CHANCE WILL BE VERY LATE IN THE
NIGHT.
THERE IS NOT A LOT OF COLD AIR WITH THIS SYSTEM...AND DEPENDING ON
WHICH MODEL YOU CHOOSE THE CHANGE OVER MAY NOT OCCUR UNTIL LATE
EVENING/AROUND MIDNIGHT WITH THE EASTERN AREAS CHANGING OVER FIRST.
THE PHASE IS REALLY WHERE THERE ARE BIG DIFFERENCES. SOME MODELS
KEEPING TOTALLY DRY OR HAVE JUST ENOUGH MOISTURE IN THE LOW LEVELS
FOR DRIZZLE/FREEZING DRIZZLE. SO A LOT OF UNCERTAINTY WITH THIS
SYSTEM.
THURSDAY/THURSDAY NIGHT...WITH THE PROXIMITY OF THE SYSTEM AND
EXPECTED SLOWNESS...ALONG WITH MID AND UPPER LEVEL LIFT
EXPECTED...EXPECT THE BEST CHANCE OF PRECIPITATION WILL BE IN THE
MORNING AND THEN RAPIDLY DECREASE AND END. IF CURRENT FORECAST PANS
OUT...THE FAR EASTERN PORTION OF THE AREA GETS 1 TO 2 INCHES.
GRADIENT AND DOWNWARD MOTION BEHIND THE SYSTEM WILL CREATE BREEZY TO
WINDY CONDITIONS. THE STRONGEST WINDS ARE AFTER THE SNOW ENDS...AND
WITH TEMPERATURES JUST ABOVE FREEZING...DO NOT EXPECT ANY BLOWING
SNOW PROBLEMS AT THIS TIME. CURRENT HIGH TEMPERATURE FORECAST LOOKS
TO BE IN GOOD SHAPE AND MADE ONLY MINOR ADJUSTMENTS. HOWEVER...IF
MORE SNOW THAN EXPECT IT WILL BE COLDER. LIGHT WINDS AND LITTLE
CLOUD COVER WILL ALLOW OVERNIGHT TEMPERATURES TO DROP A DECENT
AMOUNT.
FRIDAY...STRONG MID/UPPER LEVEL RIDGE BUILDS IN OVER THE AREA.
SURFACE WILL MOVE THROUGH AND TO THE EAST OF THE AREA DURING THE
DAY. SO DO EXPECT RECYCLED COOL AIR. THE EASTERN LOCATIONS WILL BE
THE COLDEST AND OVERALL REDUCED THE HIGH TEMPERATURES A LITTLE.
FRIDAY NIGHT THROUGH TUESDAY...MID AND UPPER RIDGE WILL BE IN PLACE
FROM FRIDAY NIGHT INTO SATURDAY NIGHT SO EXPECT MODERATING
TEMPERATURES AND DRY CONDITIONS. THE INIT WAS REASONABLE WITH THIS
AND MADE NO CHANGES.
A STRONG SHORTWAVE TROUGH...NOT UNLIKE THE ONE THAT WENT THROUGH
THIS MORNING AND SIMILAR ALSO THE SYSTEM EXPECTED WEDNESDAY NIGHT
AND THURSDAY...WILL MOVE THROUGH SUNDAY AND SUNDAY NIGHT. THE INIT
PRODUCED SLIGHT CHANCE POPS DURING THIS PERIOD AND SEEMS REASONABLE.
POSSIBLE THAT THESE CHANCES WILL INCREASE. AFTER THAT RIDGING WILL
MOVE INTO THE AREA AND BRING DRY CONDITIONS AND MODERATING
TEMPERATURES ONCE AGAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1023 PM MST TUE JAN 19 2016
VFR CONDITIONS WILL CONTINUE BRIEFLY AT KGLD AND KMCK AND THEN
DETERIORATE TO MVFR AND LOWER, ESPECIALLY AT KMCK. THE HRRR KEEPS
KGLD AT VFR WHILE THE NAM BRINGS SOME LOWER CONDITIONS. CONDITIONS
SHOULD IMPROVE RATHER EARLY WEDNESDAY MORNING EVEN AT KMCK. SOME
MID LEVEL CLOUDS REMAIN IN RESPONSE TO THE NEXT SHORTWAVE THAT
COMES THROUGH WEDNESDAY AFTERNOON. CLOUDS DECREASE BRIEFLY
WEDNESDAY EVENING IN A BRIEF LULL BEFORE THE NEXT SHORTWAVE
AFFECTS THE AREA.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
AREA FORECAST DISCUSSION
NWS JACKSON KY
222 AM EST WED JAN 20 2016
.UPDATE...
ISSUED AT 222 AM EST WED JAN 20 2016
SNOW JUST NOW BEGINNING ITS PUSH INTO CENTRAL KENTUCKY...WITH
PERHAPS SOME FLURRIES MAKING INTO THE CUMBERLAND PLATEAU. HAVE
SLOWED DOWN THE ONSET OF PRECIPITATION A BIT FOR A FEW MORE HOURS.
LOOKS LIKE AFTER 4 AM...WE SHOULD START TO SEE BETTER COVERAGE. A
LITTLE CONCERNED THE DRY AIR AND SOUTHEAST DOWNSLOPING FLOW
CURRENTLY IN PLACE MAY LIMIT THE INITIAL PUSH OF PRECIPITATION
INTO EASTERN KENTUCKY. THIS COMBINED WITH WHAT MODELS ARE
PORTRAYING AS SNOW RATIOS POSSIBLY UNDER 10 IN THE SOUTH MAY LIMIT
OVERALL SNOWFALL POTENTIAL. HAVE CHOPPED DOWN SNOWFALL TOTALS A
BIT TO MORE IN THE 1 TO 2 INCH RANGE GIVEN THE SOMEWHAT
UNFAVORABLE CONDITIONS AT THE ONSET. THE OTHER THING TO CONSIDER
IS THE BEST OMEGA STILL DOESN`T COINCIDE WITH THE DENDRITIC GROWTH
ZONE...WHICH IS PROBABLY WHY THE SNOW RATIOS ARE COMING IN LOWER.
REGARDLESS...WE SHOULD STILL BE CLOSE TO ADVISORY CRITERIA ON THE
SNOWFALL...BUT IT WILL BE A CHALLENGE TO REACH THE 4 INCHES FOR A
WARNING IN WAYNE COUNTY. REGARDLESS...BEING WE WILL GET CLOSE...AND
TO AVOID CONFUSION...WILL LEAVE HEADLINES UNCHANGED.
UPDATE ISSUED AT 1040 PM EST TUE JAN 19 2016
THE LEADING EDGE OF PRECIPITATION FROM A SYSTEM TO AFFECT THE
REGION LATER TONIGHT AND INTO WEDNESDAY NIGHT HAS MOVED INTO
SOUTHERN IL AND FAR WESTERN KY. THIS PRECIPITATION SHOULD CONTINUE
TO SPREAD EAST OVERNIGHT AND INTO WEDNESDAY MORNING.
THE 18Z NAM AND NOW THE 0Z NAM HAVE POINTED TOWARD HIGHER QPF IN
THE FAR SW COMPARED TO THE PREVIOUS FORECAST. THE 0Z GFS ALSO HAS
QPF THAT SHOULD BE ENTIRELY OR ALMOST ENTIRELY SNOW OF AROUND 0.40
INCHES IN WAYNE COUNTY. WITH SNOW RATIOS EXPECTED TO BE 10 TO 11
TO 1 THAT WOULD PROBABLY PUSH WAYNE COUNTY TO AT OR SLIGHTLY ABOVE
THE 12 HOUR WINTER STORM WARNING CRITERIA OF 4 INCHES. WITH THIS
IN MIND...WAYNE COUNTY HAS BEEN UPGRADED TO A WINTER STORM
WARNING FOR 3 TO 5 INCHES OF SNOW. NEIGHBORING COUNTIES TO WANE
SHOULD PICK UP AMOUNTS IN THE 2 TO 4 INCH RANGE...WITH AMOUNTS
TAPERING OFF FROM THERE TO THE NORTH AND EAST DUE TO DRIER AIR IN
PLACE. SOME OF THE RECENT RAP AND HRRR RUNS SUPPORT THE 0Z NAM AND
0Z GFS TO AN EXTENT ALTHOUGH THE 2Z RAP HAS HIGHER QPF FURTHER
NORTH INTO THE PULASKI TO LAUREL COUNTY CORRIDOR. THE MOST RECENT
HRRR IS SLIGHTLY LIGHTER WITH AM SNOW IN THE SW COUNTIES COMPARED
TO A COUPLE OF EARLIER RUNS...SO OVERALL SOME UNCERTAINTY REMAINS
EVEN WITH THIS SYSTEM. HOWEVER...THERE SEEMS TO BE AN UPWARD TREND
IN QPF AND SNOWFALL FOR THE FAR SW THUS THE WAYNE COUNTY UPGRADE.
AN UPDATED WSW AND HWO HAVE BEEN ISSUED.
AS FOR THE LATE WEEK SYSTEM...THE DISTURBANCES THAT SHOULD INTERACT
OR PHASE TOGETHER FOR THE EASTERN CONUS TROUGH AND LOW PRESSURE
SYSTEM ARE NOW ONSHORE OF THE WESTERN U.S. OR MOVING ONSHORE AT
THIS TIME. AS UPPER AIR NETWORKS BEGIN TO CAPTURE THE STRENGTH OF
THESE SYSTEMS...MODEL RUNS FROM 0Z THIS MORNING AND INTO WEDNESDAY
SHOULD BEGIN TO CLOSE IN WITH MORE OF A CONSENSUS. THIS SYSTEM
WILL CONTINUE TO BE MONITORED AND IS ALSO BEING HIGHLIGHTED IN
WEATHER STORIES AND HWO.
UPDATE ISSUED AT 810 PM EST TUE JAN 19 2016
OTHER THAN FINE TUNING THE HOURLY TEMPERATURE FORECAST FOR THE
NEXT FEW HOURS...NO CHANGES ARE NEEDED AT THIS TIME. AS THE 0Z
MODEL RUNS COME IN AS WELL AS THE 21Z SREF AND HRRR AND RAP RUNS
WILL BE EVALUATED FOR WHETHER OR NOT QPF AND SNOW AMOUNTS MAY NEED
TO INCREASED ACROSS THE LAKE CUMBERLAND REGION.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 406 PM EST TUE JAN 19 2016
CURRENT CONDITIONS ACROSS THE AREA FEATURE CLOUD COVER ON THE
INCREASE IN WESTERN KENTUCKY ASSOCIATED WITH A DEVELOPING SYSTEM.
MEANWHILE...IN EASTERN KENTUCKY CLOUD COVER IS DISSIPATING AS
NORTHWEST UPSLOPE FLOW DECREASES AS THE CENTER OF THE ARCTIC HIGH
HAS MOVED OVER THE AREA. THUS HAVE CLEARED SKY COVER AND SHUT OFF
THE FLURRIES ACROSS THE AREA AS WELL. AFTER 00Z TONIGHT...SKIES
WILL CLOUD UP AGAIN AS THE NEXT SYSTEM MOVES THROUGH THE
BLUEGRASS. PRECIP WILL BEGIN TO MOVE INTO THE AREA AFTER 08Z.
MODEL TRENDS HAVE KEPT THIS FEATURE WITH A GOOD AMOUNT OF LIFT AND
MOISTURE. TRENDS HAVE ALSO TAKEN THE MOST AMOUNT OF MOISTURE TO
THE SOUTH INTO CENTRAL KY AND THEN INTO TN JUST CLIPPING WETS OF
THE I-75 CORRIDOR. THIS REGION WILL LIKELY SEE THE MOST AMOUNT OF
SNOW FROM THIS FEATURE. SURFACE TEMPS AS THIS FEATURE MOVES IN
WILL JUST BE RECOVERING FROM THE ARCTIC AIR MASS THAT HAS JUST
EVACUATED THE AREA. THUS PRECIP WILL BEGIN AS SNOW FOR THIS
SYSTEM. WARMEST TEMPS THOUGH WILL BE IN THE SOUTH WITH SOUTHERLY
FLOW SETTING UP AHEAD OF THE FRONT. THUS...SNOW RATIOS WILL BE
SLIGHTLY LOWER THAN THE NORTH AS THIS FEATURE MOVES INTO THE AREA.
SNOW WILL CONTINUE ACROSS EASTERN KENTUCKY THROUGH THE DAY AND
BECOME MODERATE TO EVEN HEAVY AT TIMES. HIGH RATIOS TO THE NORTH
WILL MAKE FOR SNOWFALL AMOUNTS IN THE 1 TO 2 INCH RANGE BUT MORE
MOISTURE IN THE SOUTH WILL MAKE FOR 2 TO 3+ AMOUNTS DESPITE THE
LOWER SNOW RATIOS.
THE OTHER CONCERN FOR SNOW AMOUNTS WITH THIS FEATURE WILL BE THE
PROGRESSIVE FLOW AS THIS SYSTEM MOVES THROUGH. AS THE SYSTEM LOSES
A BIT OF MOISTURE MOVING INTO THE AREA...THE DEPTH OF THE MOISTURE
LESSENS QUITE QUICKLY BY WEDNESDAY AFTERNOON AND INTO WEDNESDAY
NIGHT. DUE TO THIS MUCH OF THE SNOW WILL CHANGE OVER TO FREEZING
DRIZZLE HEADING INTO WEDNESDAY EVENING AND WEDNESDAY NIGHT. IN
FACT...A GLAZE OF ICE IS POSSIBLE IN SOME AREAS...ESPECIALLY IN
THE SOUTH...WHERE UP TO 0.05 HUNDREDTHS ARE POSSIBLE. THIS SET UP
MAY ALSO TAKE AWAY FROM SOME OF THE SNOWFALL POTENTIAL IN THE
SOUTH. THUS...WILL KEEP THE WINTER WEATHER ADVISORY OUT FOR THE
ENTIRE AREA FROM TOMORROW MORNING AND THROUGH THURSDAY NIGHT.
HEADING INTO WEDNESDAY NIGHT...THE SYSTEM EXITS THE AREA AS THE
LAST OF THE LOW LEVEL MOISTURE EXITS AS WELL. THIS WILL BRING AN
END TO THE FREEZING DRIZZLE THREAT BEFORE THE NEXT FEATURE BEGINS
TO IMPACT THE AREA MOVING IN FROM THE SOUTH. IN FACT...WE WILL
HAVE A BRIEF BREAK IN THE PRECIP BY THURSDAY MORNING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 406 PM EST TUE JAN 19 2016
COMPLICATED FORECAST IN THE LONG TERM WITH LOTS OF ATTENTION ON A
POSSIBLE MAJOR WINTER STORM IN THE THURSDAY NIGHT THROUGH SATURDAY
TIME RANGE.
AS OUR MIDWEEK WINTER SYSTEM PASSES TO OUR EAST...TEMPERATURES
ALOFT WILL BE ON THE RISE AS A WARM FRONT AT THE SURFACE MOVES UP
THE GREAT VALLEY OF EAST TENNESSEE VALLEY. THIS WILL SEND
PRECIPITATION BACK NORTH INTO THE AREA LATE THURSDAY INTO THURSDAY
NIGHT. THERMAL PROFILE IS TRICKY BUT P-TYPE IS EXPECTED TO BE
MOSTLY RAIN ACROSS THE SOUTH BUT A MIX OF RAIN...SNOW AND FREEZING
RAIN ALONG AND NORTH OF THE HAL ROGERS PARKWAY THURSDAY
NIGHT...AND PROBABLY ALL SNOW OR A MIX OF FREEZING RAIN AND SNOW
FROM I-64 NORTH. FORECAST MODELS THEN DIVERGE INTO FRIDAY BUT THE
PRESENCE OF AN INVERTED TROUGH EXTENDING UP THE GREAT VALLEY OF
EAST TENNESSEE INTO THE CUMBERLAND VALLEY WOULD SUPPORT A SCENARIO
WHERE THE WARM NOSE ALOFT EDGES FURTHER NORTH CAUSING PRECIP TO
MIX WITH OR CHANGE TO RAIN PERHAPS AS FAR NORTH AS THE MOUNTAIN
PARKWAY AND POSSIBLY EVEN I-64. THE NORTHWARD EXTEND TO THE CHANGE
TO RAIN DEPENDS GREATLY ON THE STRENGTH AND TRACK OF THE SURFACE
LOW...WITH WHICH THERE IS JUST A LOT OF UNCERTAINTY DUE TO MODEL
DIFFERENCES SO TRIED TO PAINT WITH A BROAD BRUSH AS FAR AS THE
ACTUAL P-TYPE FORECAST GOES RIGHT NOW THROUGH THE DAY FRIDAY.
SO...WHILE THE ACTUAL WEATHER YOU WILL SEE REMAINS UNCERTAIN
THURSDAY NIGHT AND FRIDAY...PLAN TO BE IMPACTED BY THE WEATHER IN
SOME FORM OR FASHION IF YOU HAVE TRAVEL PLANS AND MONITOR
FORECASTS AS OUR CONFIDENCE IN THE DETAILS IMPROVES OVER THE NEXT
DAY OR SO.
MODELS ARE FAIRLY CONSISTENT THAT COLDER AIR WILL WRAP IN BEHIND
THE DEPARTING SURFACE LOW FRIDAY EVENING CHANGING ALL PRECIP TO
SNOW QUICKLY FROM NORTHWEST TO SOUTHEAST. THE SNOW WILL LIKELY
CONTINUE THROUGH AT LEAST SATURDAY MORNING...AND POSSIBLY EVEN
INTO SATURDAY NIGHT AS THE UPPER LOW IS SLOW TO PIVOT THROUGH. THE
POTENTIAL EXISTS FOR SEVERAL INCHES OF SNOW.
THE REMAINDER OF THE EXTENDED WILL FEATURE WARMING TEMPS...
ALTHOUGH POTENTIAL SNOW COVER WILL HAVE A YET TO BE DETERMINED
INFLUENCE THERE. ANOTHER SYSTEM IS PROGGED TO DEVELOP OVER THE
SOUTHERN PLAINS AND THEN MOVE NORTHEAST SPREADING ANOTHER CHANCE
FOR PRECIPITATION ACROSS THE AREA AS EARLY AS MONDAY. THIS SHOULD
BE RAIN AS IT APPEARS RIGHT NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 222 AM EST WED JAN 20 2016
VFR WILL CONTINUE FOR THE NEXT 2 TO 4 HOURS. BY LATE TONIGHT...A
WEATHER DISTURBANCE WILL BRING SNOWFALL TO THE FAR SOUTHWEST BY
09Z...SPREADING ACROSS THE ENTIRE AREA BY 16Z. THIS WILL THEN
RESULT IN DETERIORATION INTO MVFR AND THEN IFR AND POSSIBLY NEAR
OR BELOW AIRPORT MINS AT TIMES FOR VIS IN THE FALLING SNOW AND AND
CIGS DURING SNOW AND AFTER IT DEPARTS AND TAPERS TO DRIZZLE OR
FREEZING DRIZZLE. WINDS WILL BE LIGHT TO NEAR CALM THROUGH THE
PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 7 AM EST
THURSDAY FOR KYZ052-060-088-104-106>110-112-113-115-117>120.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR KYZ044-050-
051-058-059-068-069-079-080-084>087-111-114-116.
WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR KYZ083.
&&
$$
UPDATE...KAS
SHORT TERM...SHALLENBERGER
LONG TERM...ABE
AVIATION...KAS
AREA FORECAST DISCUSSION
National Weather Service Paducah KY
1118 PM CST TUE JAN 19 2016
.UPDATE...
Issued at 642 PM CST TUE JAN 19 2016
Watching very closely the precipitation across SEMO, where light
freezing rain/drizzle has been reported and has caused very
dangerous travel conditions. Issued a SPS, and highlighted it more
strongly in the social media realm. May take a look at the WSW.
Thing is, as the upper system moves closer and precip increases,
precip loading, top down cooling will start to erode the "warm"
layer, or at least suppress it toward the MO/AR border, and
transition precip to mainly sleet and snow early this evening. So
for now, will handle this as a very short term event, and not
complicate the overall message. Will make some minor changes to
the grid forecast in this area. The RAP thermal depictions support
this approach.
CN
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 131 PM CST TUE JAN 19 2016
With 12z model suite painting low end 4 tenths qpf, and high end
6 tenths, and ratios low end 12 to 1, and high end 17 to 1, per
collab with WPC and adjacent WFO`s...have upgraded to warn all
areas for broad 3 to 5 inch expectation.
More specifically, some heavier snow could paint a swath of
locally higher amounts (depending upon the solution)... and
higher liquid to snow ratios in cold low to mid 20s air... could
potentially yield a 6+ inch swath. The main threat area for this
is roughly latitudinally along the Ohio river thru the heart of
the FA and southward toward the AR/TN borders.
On the flip side, if more scant amounts of qpf across our north
occur (visa vi the GFS), and using a less gracious LSR, we could
see lesser 2 to 2.5" totals along the I-64 corridor from Mount
Vernon IL into southwest IN.
In summary, broad 3 to 5 inch totals expected snow/sleet. Some
chance slightly lower 2 inch totals possible north, and higher 6+
inch totals a possibility across south-central ptns. Cant rule out
some hundredths of freezing rain across mainly srn border
counties, but focusing mostly on snow/sleet potential given
consistency of colder/further southern/eastern track.
Factors at play for a little more sleet vs snow include 3 to 6K
foot depth of warm nose ranging from -1C to +2C for at times 3 to
6 hrs of pcpn time period. This skews totals a little toward lower
end of aforementioned ratios, if it plays out.
Adjusted start time of WSW to 00z, given accumulating snows could
be ongoing at 03z for farthest western portions of SEMO/SWIL. End
time maintained at 18Z, but effectively ends at 15Z for all but
farthest southeastern counties...as pcpn shuts off sharply
northwest to southeast thru the morning hours Wednesday.
.LONG TERM...(Thursday through Tuesday)
Issued at 255 PM CST TUE JAN 19 2016
Another messy round of winter weather will follow our mid week
event. Models are in good agreement showing a low pressure system
centered over central Mississippi at 00z Friday. Being on the cold
side of the low along with the expected snow pack across our
region, a majority of the precipitation Thursday into Friday will
be freezing or frozen. Precipitation is expected to start as a mix
of freezing rain, sleet and snow across all but our north and
northwest counties, where precipitation should begin as snow and
remain snow through the event. Models imply temperatures briefly
reaching 33 to 37 degrees across most areas by Thursday afternoon,
which would switch us to rain. However confidence is a bit low on
how much warming we can get, so kept most areas as a mix except
for a portion of west Kentucky and southeast Missouri.
For Thursday night, any areas that begin as a mix will switch to
all snow by midnight as the low moves off to our southeast
overnight. The snow will continue into Friday, tapering off from
west to east Friday afternoon into Friday night. Right now 1 to 3
inches of snow is possible, but amounts are questionable at this
point and will greatly depend on how warm our surface temperatures
can get.
The weekend will be dry as high pressures moves across the Gulf of
Mexico. Temperatures will reach the middle 30s Saturday, and
around 40 degrees Sunday. Another round of precipitation will
return for Monday. Models take a surface low right over the PAH
forecast area late Monday into Monday night. Rain is possible
Monday, then as the low moves overhead and east of us, rain will
mix with and change over to snow Monday night. Rain or snow will
then be possible for Tuesday into Tuesday night, but we will have
to continue to watch the track of the low to see just how warm or
cold we will be for the beginning of the work week.
&&
.AVIATION...
Issued at 1118 PM CST TUE JAN 19 2016
Trends across Southern Illinois and into Southeast Missouri
finally closing in on lower visibilities and ceilings with
increased snowfall. May still be 1-2 hours fast at KPAH and KOWB,
but model guidance still suggesting a sharp increase in snowfall
after midnight, lowering ceilings and visibilities through
daybreak.
Made slight timing changes for lower ceilings at KCGI and KPAH,
but continued downward trend toward IFR conditions between 06-12z
Wednesday.
&&
.PAH Watches/Warnings/Advisories...
IL...Winter Storm Warning until noon CST Wednesday for ILZ075>078-
080>094.
MO...Winter Storm Warning until noon CST Wednesday for MOZ076-086-087-
100-107>112-114.
IN...Winter Storm Warning until noon CST Wednesday for INZ081-082-
085>088.
KY...Winter Storm Warning until noon CST Wednesday for KYZ001>022.
&&
$$
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1137 PM CST TUE JAN 19 2016
.AVIATION...
SCATTERED SHOWERS WILL ACCOMPANY AN EASTWARD MOVING COLD FRONT
DURING THE OVERNIGHT HOURS. SOUTHEAST WINDS AROUND 5 TO 10 KNOTS
AHEAD OF THE FRONT TO BECOME NORTHWEST BEHIND THE FRONT. CEILINGS
TO BECOME IFR AROUND DAYBREAK ACROSS AREA TERMINALS WITH LITTLE
IMPROVEMENT THROUGH 20/18Z. OTHERWISE...VFR CONDITIONS TO PREVAIL
THROUGH 21/00Z WITH MVFR/IFR CEILINGS POSSIBLE THEREAFTER. /05/
&&
.PREV DISCUSSION... /ISSUED 959 PM CST TUE JAN 19 2016/
DISCUSSION...
A LINE OF BROKEN CONVECTION HAS DEVELOPED OVER THE LAST COUPLE OF
HRS JUST AHEAD OF A COLD FRONT THAT IS ENTERING THE NWRN ZONES.
00Z KSHV RAOB SHOWS A PRONOUNCED DRY LAYER BETWEEN 850-560
MB...INDICATIVE OF SHOW MID LVL DRY SLOTTING IN THE WAKE OF A
DEPARTING SHORTWAVE TROUGH PER LATEST WV LOOPS. SOME ADDITIONAL
MID/UPPER LVL MOISTURE MOVING INTO THE SRN PLAINS COULD HELP THE
ATMOSPHERE MOISTEN FROM THE TOP DOWN IF IT ARRIVES BEFORE THE
FRONT. OTHERWISE...PRECIP WILL REMAIN SPOTTY AND SCATTERED AT
BEST. RAIN CHANCES MIGHT BE A BIT HIGHER ACROSS SRN AR DURING THE
EARLY MORNING HRS AS VERTICAL ASCENT MIGHT BE SLIGHTLY HIGHER DUE
TO THE PROXIMITY OF A SFC LOW AND THE UPPER TROUGH AXIS.
QUITE A FEW CHANGES WERE MADE IN THE GRIDS DURING THE FIRST 72 HRS
OF THE FCST BASED ON THE LATEST HRRR AND THE 00Z NAM. BIGGEST
CHANGES WERE MADE TO POPS AND TEMPS.
UPDATED PRODUCTS WILL BE SENT SHORTLY. /09/
PREV DISCUSSION... /ISSUED 540 PM CST TUE JAN 19 2016/
AVIATION...
CONDITIONS TO DETERIORATE OVERNIGHT AS A COLD FRONT MOVES ACROSS
THE AREA. CEILINGS TO BECOME MVFR AHEAD OF THE FRONT FOLLOWED BY
AN INCREASE IN COVERAGE OF RAIN SHOWERS AFTER 20/06Z. WINDS TO
BECOME NORTHWEST 5 TO 10 KNOTS BEHIND THE FRONT ACROSS MOST AREAS
BY DAYBREAK. OTHERWISE...IFR CEILINGS AND VISIBILITIES BETWEEN
20/12Z-20/16Z TO GRADUALLY IMPROVE THROUGHOUT THE DAY. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 47 56 50 62 / 40 20 40 50
MLU 48 57 49 65 / 30 40 40 70
DEQ 39 49 40 53 / 40 10 50 60
TXK 41 50 45 56 / 50 10 50 60
ELD 43 52 44 58 / 50 40 50 70
TYR 41 53 49 60 / 40 10 40 40
GGG 43 54 50 61 / 40 10 40 50
LFK 47 59 54 65 / 30 20 30 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
05/05/05
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1203 AM EST WED JAN 20 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 354 PM EST TUE JAN 19 2016
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SHRTWV RDG
STRETCHING FM NW ONTARIO IN MN WITHIN NW FLOW ALF ON WRN FLANK OF
DEPARTING UPR LO OVER SE CANADA. ASSOCIATED SFC HI PRES RDG
STRETCHES FM NW ONTARIO THRU THE UPR MS RIVER VALLEY AND TOWARD THE
OH RIVER VALLEY. NW FLOW OF COLD AIR...WITH H925 TEMPS ARND -15C
OVER THE UPR LKS...IN ADVANCE OF THIS SLOWLY APRCHG RDG IS STILL
CAUSING SOME LES...BUT BANDS ARE WEAKER/MORE DISORGANIZED WITH
STRONG SUBSIDENCE ASSOCIATED WITH THE APRCHG RDG LOWERING INVRN BASE
TOWARD 3-4K FT AGL PER MQT VWP. LLVL WINDS ARE BEGINNING TO BACK AS
WELL AHEAD OF THE APRCHG SFC RDG...SO BANDS ARE SHIFTING/LIMITING
RESIDENCE TIME. PLENTY OF LO CLDS LINGER UNDER THE LOWERING INVRN
DESPITE DRY NATURE OF THE NEAR SFC LYR UPSTREAM /WHERE SFC DEWPTS
ARE AOB -20F OVER MUCH OF NRN MN...BUT SOME BREAKS ARE BEGINNING TO
SHOW UP OVER THE FAR W NEAR IWD CLOSER TO THE INCOMING SFC HI PRES/
DRY LLVL AIR AND OVER THE SCENTRL WHERE NW FLOW IS DOWNSLOPING.
THERE IS ANOTHER SHRTWV STRETCHING FM SASKATCHEWAN INTO THE NRN
PLAINS THAT IS DIGGING SEWD...AND SOME HI/MID CLDS AHEAD OF THIS
DISTURBANCE ARE SPREADING INTO MN.
MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON LINGERING LES TRENDS/
LO CLDS AND IMPACT ON TEMPS.
TNGT...SFC HI PRES RDG AXIS IS FCST TO SHIFT SLOWLY TO THE E AND
STRETCH FM THE UPR OH VALLEY INTO UPR MI AT 12Z WED. AS THE LLVL
WINDS CONTINUE TO BACK TOWARD THE WSW...ANY LINGERING SN SHOWERS
OVER THE NRN KEWEENAW AND NEAR LK SUP E OF GRAND MARAIS SHOULD LIFT
OUT INTO LK SUP. SINCE THE WINDS WL SHIFT OFFSHORE AND THE INVRN
BASE WL LOWER WITH MORE ACYC LLVL FLOW...EXPECT THE BULK OF THE LO
CLDS TO SHIFT OVER THE LK AS WELL. ALTHOUGH THE SETUP SEEMS
FAVORABLE FOR VERY LO TEMPS WITH LGT OFFSHORE WINDS...MID/HI CLDS ON
THE NRN FRINGES OF SHRTWV DIGGING TO THE SE ARE FCST TO MOVE OVER
THE CWA AND LIMIT THE DIURNAL TEMP FALL. SO ALTHOUGH THERE MAY BE
SOME SUB ZERO MIN TEMPS OVER THE INTERIOR...WIDESPREAD MIN TEMPS
UNDER -10F AS OBSVD THIS MRNG OVER NRN MN ARE NOT LIKELY.
WED...LARGE SCALE QVECTOR DVGC AHEAD OF SHRTWV RDG AND UNDER SFC RDG
AXIS WL MAINTAIN MAINLY DRY WX FOR MOST OF THE CWA...WITH ANY SN
SHOWERS OVER LK SUP NEAR LK INDUCED TROF FCST TO LINGER OVER THE N
HALF OF THE LK. DURING THE DAY...MANY OF THE MODELS SHOW SOME MSTR
RETURN OVER MAINLY THE WRN CWA IN THE SW FLOW BTWN THE SFC RDG
SHIFTING SLOWLY TO THE E AND A SHRTWV APRCHG LATE IN THE DAY FM THE
NW. BUT SINCE ANY FORCING AND LLVL MSTR INFLOW WL BE MINIMAL...OPTED
TO RETAIN ONLY SCHC POPS OVER THE WRN CWA WHERE THE MOISTENING IS
FCST TO BE A BIT MORE ROBUST. EXPECT A SOMEWHAT WARMER AFTN WITH H85
TEMPS REBOUNDING TO ARND -12C BY 00Z THU.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 446 PM EST TUE JAN 19 2016
BY 00Z THURSDAY THE SFC HIGH WILL HAVE SLIPPED TO IL-OH...WITH A
WEAK RIDGE/LAKE INDUCED LOW SLOWLY DEEPENING ACROSS LAKE SUPERIOR AS
THE RIDGE EXITS. THE NEXT IN A SERIES OF SHORTWAVES WILL ASSIST IN
THE LIGHT SNOW SHOWER POTENTIAL WEDNESDAY NIGHT...TRACKING FROM SW
ONTARIO AT 00Z TO FAR N LAKE HURON BY DAYBREAK THURSDAY. THE MAIN
IMPACT WILL BE TO INCREASE NW FLOW ACROSS THE KEWEENAW PENINSULA
BEHIND THE WEAK SFC-500MB TROUGH AND ENHANCING LIGHT SNOW SHOWERS
THERE. 850MB TEMPS WILL BE AROUND -11C. NOT EXPECTING ADVISORY
SNOW AMOUNTS AT THIS TIME.
THE NEXT SFC HIGH SITUATED OVER MANITOBA AND N DAKOTA THURSDAY WILL
PUSH ACROSS MN AND W LAKE SUPERIOR ON FRIDAY...BUT WILL ONLY SLOWLY
BREAK DOWN THE LINGERING WEAK TROUGH OVER E LAKE SUPERIOR/E UPPER MI
BY FRIDAY NIGHT. SFC WINDS WILL SHIFT OUT OF THE N THURSDAY NIGHT
THROUGH FRIDAY AND 850MB TEMPS WILL FALL TO -12 TO -14C...BUT WITH
LIMITED MOISTURE...EXPECT SNOWFALL LESS THAN 2IN.
ANOTHER DRY PERIOD IS EXPECTED FRIDAY NIGHT THROUGH SATURDAY NIGHT
AS ANOTHER AREA OF HIGH PRESSURE SHIFTS ACROSS THE REGION. BY
SATURDAY MORNING ...THE NEXT LOW WILL BET SET UP ACROSS S CENTRAL
CANADA WHILE MUCH OF THE ATTENTION WILL BE ON THE TRACK AND TIMING
OF THE LOW OFF THE MID ATLANTIC COAST. UPPER MI WILL REMAIN IN
BETWEEN SYSTEMS UNTIL THE CANADIAN LOW SHIFTS ACROSS ONTARIO SUNDAY
AND THE EASTERN LOW MOVES OFF THE NEW ENGLAND STATES. THE TROUGH
LOOKS TO CROSS UPPER MI LATE SUNDAY NIGHT/MONDAY MORNING. THE GFS
AND ECMWF ARE OVER 12HRS ON TIMING WHEN THE NEXT SWATH OF SNOW WILL
CROSS UPPER MI SUNDAY AFTERNOON-MONDAY...WITH DIFFERENCES IN THE
TIMING OF THE NEXT LONGWAVE TROUGH MOVING ACROSS THE CENTRAL PLAINS
AND GREAT LAKES STATES. MODERATE TO HIGH CONFIDENCE EXISTS IN THE
ONGOING FORECAST FOR UPPER MI UNTIL SUNDAY. OTHERWISE THE CONSENSUS
FOR MONDAY-TUESDAY WOULD BE FOR AT LEAST SOME COOLER WITH 850MB
TEMPS FALLING AGAIN TO -10 TO -12C.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1203 AM EST WED JAN 20 2016
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT SAW. LAKE EFFECT
MVFR DECK AT CMX WILL GO AWAY WITH SW WINDS KEEPING THEM
OFFSHORE...THEN MVFR CONDITIONS RETURN BY LATE WED EVENING. AT
IWD...VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE PERIOD. THERE
WILL BE TIMES WHEN HIGH END MVFR DECK COMES INTO IWD WED MORNING AND
AGAIN WED AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 PM EST TUE JAN 19 2016
WITH A RELATIVELY WEAK PRES GRADIENT EXPECTED OVER THE UPPER LAKES
MOST OF THIS COMING FORECAST PERIOD...WINDS WILL REMAIN UNDER 25 KTS
MOST OF THE TIME. THE BEST CHANCE FOR SW WINDS UP TO 30 KTS WILL BE
ON SAT...WHEN A SHARPER GRADIENT BETWEEN HI PRES STRETCHING FROM NEW
ENGLAND INTO THE MID MS RIVER VALLEY AND A LO PRES TROF APPROACHING
FROM THE NW MAY SUPPORT THE STRONGER WINDS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1145 PM CST TUE JAN 19 2016
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 336 PM CST TUE JAN 19 2016
MAIN CONCERN IS FOG POTENTIAL TONIGHT. GENERAL SYNOPTIC PATTERN IS
QUITE PROGRESSIVE AS WE TRANSITION TO A HIGHER AMPLITUDE SCENARIO.
TONIGHT...THE CONCERN GOES TO FOG POTENTIAL TONIGHT AS WIND WILL BE
LIGHT FROM THE SOUTH. THE HRRR IS HITTING THE FOG POTENTIAL A LITTLE
HARD CENTRAL AND WEST. THE SREF IS ALSO HITTING FOG A LITTLE HARD
EVERYWHERE ACROSS THE CWA...ESPECIALLY WEST. I WENT WITH STRONG
WORDING IN THE FORECAST TO AREAS RATHER THAN PATCHY AND EXTENDED THE
FOG MENTION FARTHER EAST THAN THE PREVIOUS FORECAST.
WE MAY SEE A LITTLE SUN WEDNESDAY MORNING BEFORE IT CLOUDS BACK UP
IN ADVANCE OF THE NEXT WAVE QUICKLY APPROACHING. WARM AIR ADVECTION
SHOULD BOOST TEMPERATURES A GOOD 10 DEGREES WARMER ON WEDNESDAY
COMPARED TO TODAY. NOT EXPECTING PRECIP UNTIL PERHAPS BETWEEN 21Z
AND 00Z THURSDAY IN OUR FAR SOUTH...WHERE RAIN/SNOW COULD
OCCUR...BUT THE BETTER CHANCES WILL LIKELY BE TOWARD WEDNESDAY
NIGHT...IN THE LONG TERM FORECAST.
SUPERBLEND TEMPERATURES LOOKED REASONABLE...WHICH LOWERED
TEMPERATURES A BIT FOR WEDNESDAY HIGHS COMPARED TO THE PREVIOUS
FORECAST. THIS SEEMS REASONABLE CONSIDERING LINGERING FOG POTENTIAL
AND INCREASING SKY COVER BY AFTERNOON. BCONSRAW AND NAM12 SOLUTIONS
INDICATE THAT IT MIGHT EVEN BE A BIT COOLER THAN THE MID 30S I HAVE
ADVERTISED IN THE FORECAST....WITH COOLER TEMPERATURES EAST AND
WARMER WEST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 336 PM CST TUE JAN 19 2016
ALOFT: VERY LITTLE CHANGE IN THE PATTERN IS ENVISIONED FOR AT LEAST
THE NEXT WEEK. A MEAN TROF WILL REMAIN OVER THE E PAC WITH THE MEAN
RIDGE OVER WRN N AMERICA. THE FLOW WILL INITIALLY BE MODERATELY
AMPLIFIED BUT WILL DEAMPLIFY TEMPORARILY AS A TROF MOWS DOWN THE
RIDGE FRI-SAT AND EMERGES INTO THE PLAINS SUN-MON. NW FLOW WILL
FOLLOW TUE.
AT 00Z/THU A SHORTWAVE TROF WILL BE MOVING IN AND AMPLIFYING...WITH
A MID-LVL CIRCULATION CLOSING OFF OVER NEB/KS BY 06Z. THIS LOW WILL
DROP SSE THU WITH QUIETER WX TO FOLLOW.
SURFACE: A WEAK COLD FRONT WILL MOVE THRU WED NIGHT. LEE
CYCLOGENESIS WILL BE UNDERWAY WED EVE WITH THE SFC LOW FAR TO THE S
OVER TX. CANADIAN HIGH PRES WILL GRADUALLY BUILD IN THU-FRI. RETURN
FLOW DEVELOPS SAT AS A CLIPPER HEADS E ACROSS SRN CANADA. A NICE
DOWNSLOPE-WARMED AIR MASS WILL OVERTAKE THE REGION...BUT SNOW ON THE
GROUND WILL TEMPER THE WARM-UP. THE NEXT PAC COOL FRONT WILL BE
MAKING ITS WAY THRU THE WRN USA AND WILL ARRIVE HERE LATE SUN. HIGH
PRES WILL MOVE IN MON AND DROP INTO THE SRN PLAINS TUE.
SOME DAILY DETAILS...
WED NIGHT: SNOW WILL BE BLOSSOMING OVER N-CNTRL KS AND EXPANDING N
INTO S-CNTRL NEB.
THU: A SWATH OF SNOW WILL PROBABLY STILL ENCOMPASS MUCH OF THE FCST
AREA THRU THE MORNING...RESULTING IN PERIODS OF SNOW. IT WILL
DIMINISH AND END IN THE AFTERNOON.
CURRENT EXPECTATION IS THAT MOST IF NOT ALL THE ACCUMULATING SNOW
WILL FALL WED NIGHT. WHILE SNOW WILL CONT INTO THU THE LIFT WILL NOT
BE ENOUGH TO RESULT IN MUCH ACCUM.
SNOW RATIOS: THIS IS TOUGH BECAUSE THE MESOSCALE NATURE OF THIS
SYSTEM WILL RESULT IN HIGHLY NON-UNIFORM LIFT. HIGHER UPWARD
VERTICAL MOTION (UVM) WILL RESULT IN HIGHER RATIOS WITHIN THE BAND.
GIVEN THAT THE BAND SHOULD BE TRANSIENT...KEPT RATIOS IN THE 10-12
RANGE.
BASED ON NAM SOUNDINGS...UVM WILL BE FAIRLY GOOD BELOW THE DGZ FROM
I-80 SOUTH. WITH TEMPS WARMER THAN -5C...THIS WILL RESULT IN
SUBSTANTIAL RIMING AND RATIOS CLOSE TO 10:1...IE A WETTER SNOW. N OF
I-80...IF THE NAM IS CORRECT UVM WILL BE WEAK RESULTING IN LESSER
QUALITY/SMALLER FLAKES. THAT TOO SUPPORTS A LOWER RATIO OF 10 OR
LESS.
ACCUMS: THESE RATIOS OFFER 1-2" AND THAT IS THE OFFICIAL FCST AT
THIS POINT...WITH 3-4" POSSIBLE IN A SMALLER AREA WHERE THE BAND IS
MORE PERSISTENT. WE JUST DON`T KNOW WHERE THAT WILL OCCUR.
SNOW ALGORITHMS FROM THE 06Z/12Z 20KM GFS AND 12Z/18Z NAM OFFER 2-4"
ACROSS MUCH OF THE FCST AREA...WITH ISOLATED 6" AMTS POSSIBLE.
THE EC CONTS TO BE ON THE HEAVY SIDE OF THE GUIDANCE DISTRIBUTION
CONSISTENTLY DUMPING ABOUT .50" SOMEWHERE NEAR ROOKS/OSBORNE/
MITCHELL COUNTIES. THAT INCLUDES THE LAST 4 RUNS. HOWEVER...THE 12Z
EC ENSEMBLE MEAN PROBABILITY FOR .50" IN 24 HRS 10% OR LESS. SO THAT
CONSTRAINS ME FROM GETTING OVERLY EXCITED.
WINDS WILL NOT BE A FACTOR WITH THIS EVENT.
FRI: DECREASING CLOUDS AS SUBSIDENT NW FLOW MOVES IN. HIGH TEMPS
PROBABLY COLDER THAN NORMAL.
SAT: TEMPS AT LEAST NORMAL IF NOT ABOVE. SNOW ON THE GROUND IS A
HUGE MITIGATING FACTOR. OTHERWISE...WIDESPREAD HIGHS IN THE 40S AND
50S WOULD BE ON THE TABLE.
SUN-MON: INCREASING CLOUDS. COOLER. POSSIBLY A TOUGH OF LIGHT
PRECIP AS THE FRONT/TROF MOVE IN.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1135 PM CST TUE JAN 19 2016
PRIMARY FORECAST CONCERN REVOLVES AROUND FOG AND STRATUS
POTENTIAL...ESPECIALLY THROUGH THE MORNING HOURS. WIDE SWATH OF
MVFR CEILINGS CONTINUES TO AFFECT BOTH TERMINAL AREAS...THOUGH
THEY ARE ON THE WRN FRINGES OF THE CLOUD COVER. CONFIDENCE IN THE
TIMING OF ANY IMPROVEMENTS OF CEILINGS DUE TO MOVEMENT OF THE
STRATUS IS NOT HIGH...AS EVEN JUST A FEW HOURS
OUT...MODELS/GUIDANCE CONTINUE TO SHOW NOTABLE DIFFERENCES. AS FAR
AS WINDS GO...NO SIGNIFICANT CHANGES EXPECTED THROUGH THE
PERIOD...REMAINING S/SERLY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...ADP
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1122 PM CST TUE JAN 19 2016
.SYNOPSIS...
ISSUED AT 325 PM CST TUE JAN 19 2016
H5 ANALYSIS THIS MORNING HAD A SHORTWAVE TROUGH EXTENDING
FROM THE DAKOTAS INTO WESTERN NEBRASKA AND SRN COLORADO. UPSTREAM OF
THE TROUGH...A LOW AMPLITUDE RIDGE EXTENDED FROM SWRN UTAH...NWD
INTO SRN ALBERTA. WEST OF THE RIDGE...A SHORTWAVE TROUGH WAS PRESENT
OFF THE COAST WASHINGTON STATE...OREGON AND NORTHERN CALIFORNIA.
CURRENT WV IMAGERY...HAS THE SHORTWAVE EXTENDING FROM EASTERN SOUTH
DAKOTA...INTO SOUTH CENTRAL NEBRASKA. FURTHER WEST...A BROAD PLUME
OF PACIFIC MOISTURE WAS NOTED AND EXTENDED FROM CALIFORNIA...EWD
INTO THE INTER MOUNTAIN WEST. A SECONDARY FEED OF MOISTURE EXTENDED
FROM BAJA CALIFORNIA INTO TEXAS AND THE OZARKS. AT THE
SURFACE...LIGHT SNOW IN ASSOCIATION WITH THE SHORTWAVE TROUGH...HAD
EXITED THE FORECAST AREA BY LATE MORNING. SNOW AMOUNTS WERE ON THE
ORDER OF 1 TO 2 INCHES ACROSS THE EASTERN HALF OF THE FORECAST
AREA...WITH SOME LOCALLY HEAVIER AMOUNTS UP TO 3 INCHES IN CUSTER
COUNTY. SEE OMAPNSLBF FOR DETAILS. SKIES WERE GENERALLY CLOUDY THIS
AFTERNOON WITH THE EXCEPTION OF LOCATIONS ALONG AND WEST OF HIGHWAY
61 FROM MERRIMAN TO IMPERIAL. TEMPERATURES THIS AFTERNOON WERE
GENERALLY IN THE 20S TO LOWER 30S.
&&
.UPDATE...
ISSUED AT 908 PM CST TUE JAN 19 2016
BINGO...DENSE FOG HAS FROMED ACROSS NRN NEB. THE RAP MODEL SHOWS
THIS FOG MOVING EAST OVERNIGHT AND LASTING 3 TO 6 HOURS. IT IS
POSSIBLE IT COULD FORM FARTHER SOUTH ACCORDING TO THIS MODEL BUT
THAT REMAINS UNCERTAIN AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 325 PM CST TUE JAN 19 2016
CLEARING CONTINUES TO SPREAD FROM WEST TO EAST ACROSS THE AREA THIS
EVENING. HOWEVER THE DRY AIR ALOFT AND GOOD RADIATIONAL COOLING WILL
QUICKLY COOL THE SFC TO THE DEW POINT. BOTH THE SHREF AND NAM ARE
SUGGESTING SOME FOG TO DEVELOP...AND WITH THE MELTING OF SOME OF THE
LIGHT SNOW FROM THIS MORNING ADDING TO THE BL MOISTURE AND NEAR CALM
WINDS...GROWING CONFIDENCE THIS COULD DEVELOP. UNSURE ON HOW DENSE
IT WILL GET SO NO HEADLINE BUT WILL NEED TO MONITOR THIS CLOSELY.
LOWS WILL BE MILD FOR MID JANUARY IN THE TEENS TO AROUND 20.
TOMORROW THE FOG WILL SLOWLY ERODE AS THE NEXT WAVE EJECTS ONTO THE
PLAINS. MOISTURE IS ON THE INCREASE...HOWEVER A DRY MID LEVEL WILL
HAVE TO BE OVERCOME BEFORE ANYTHING REACHES THE GROUND...THUS EXPECT
THE DAYTIME TO BE DRY. WEAK RIDGING AHEAD OF THE WAVE WILL PUSH SOME
WARM AIR BRIEFLY INTO THE REGION WHICH SHOULD HELP PUSH EARLY HIGHS
INTO THE MID 30S TO LOWER 40S...WARMEST WERE LITTLE TO NO SNOW PACK.
IF CLOUDS THICKEN QUICKLY...HIGHS COULD BE TO OPTIMISTIC.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 325 PM CST TUE JAN 19 2016
MID RANGE...WEDNESDAY NIGHT THROUGH FRIDAY...THE MAIN FORECAST
CHALLENGE IN THE MID RANGE IS SNOWFALL POTENTIAL WITH A SHORTWAVE
SYSTEM PROGGED TO CROSS THE CENTRAL AND SRN PLAINS WEDS NIGHT INTO
THURSDAY. BEGINNING LATE WEDNESDAY AFTERNOON...WITH THE APPROACH OF
AN UPPER LEVEL JET STREAK...A SHORTWAVE TROUGH...WILL DEEPEN AS IT
TRACKS FROM WYOMING INTO KANSAS. LIFT WILL BEGIN TO INCREASE
OVERNIGHT WEDNESDAY NIGHT...NORTH OF THE SHORTWAVE...WHICH CLOSES
OFF AT BOTH THE H7 AND H5 LEVELS AFTER 06Z THURSDAY. CROSS SECTIONS
TAKEN ACROSS THE EASTERN CWA INDICATE PLENTY OF DENDRITIC ZONE
MOISTURE...ALONG WITH A 12 HR PERIOD (06Z-18Z THURSDAY) OF FAVORABLE
LIFT. THIS AREA OF LIFT IS COLLOCATED WITH AN INVERTED SURFACE TROUGH
OF LOW PRESSURE WHICH IS PRESENT ACROSS THE EASTERN CWA...OR MAINLY
ALONG THE HIGHWAY 183 CORRIDOR FROM ANSLEY TO SPRINGVIEW. SREF QPF/S
AS WELL AS THE OPERATIONAL GFS AND NAM SOLNS INDICATE 10 TO 20
HUNDREDTHS OF AN INCH ALONG THIS CORRIDOR...WHICH BASED ON COBB
RATIOS OF 12 TO 1...YIELDS 1 TO 2 INCHES OF SNOW IN THE EASTERN HALF
OF THE CWA. BASED ON THE CROSS SECTIONS...THIS WILL BE A FAIRLY LONG
(12 HRS)...LIGHT INTENSITY EVENT. ATTM FEEL FAIRLY CONFIDENT IN
QPF/S AND ACCUMS...HOWEVER...LAYER PWATS IN THE NAM SOLN ARE RUNNING
A QUARTER TO BRIEFLY A HALF AN INCH DURING THE PERIOD AND THIS IS
CONCERNING. IF THIS VERIFIES...WE COULD BE LOOKING AT MORE SNOW
ACCUMS THAN CURRENT THINKING. WILL CONTINUE TO MONITOR THIS WITH THE
NEXT COUPLE OF FCST CYCLES. PROGRESSING INTO THURSDAY
AFTERNOON...THE UPPER LEVEL LOW WILL TRACK SOUTHEAST INTO THE
OZARKS...AS A RIDGE BEGINS TO BUILD INTO THE INTER MOUNTAIN WEST.
LIFT WILL BEGIN TO WEAKEN QUICKLY BY THURSDAY AFTERNOON IN THE
EAST...WHILE HIGH PRESSURE BUILDS SOUTH FROM THE EASTERN DAKOTAS.
SUBSIDENCE AND DRIER AIR...WILL BRING THE THREAT FOR SNOW TO AN END
DURING THE AFTERNOON HOURS. ON THURSDAY NIGHT...HIGH PRESSURE WILL
BUILD SOUTH INTO EASTERN NEBRASKA. LOW TEMPERATURES WERE TRENDED
DOWNWARD IN THE EAST GIVEN ITS PROXIMITY TO THE TRACK OF THE HIGH
WITH GUIDANCE UNDERCUT 2 TO 5 DEGREES. HIGH PRESSURE WILL TRANSITION
EAST INTO MINNESOTA AND NORTHERN IOWA BY FRIDAY AFTERNOON. WARMER
AIR WILL BEGIN TO PUSH INTO WESTERN NEBRASKA BY AFTERNOON...WITH H85
TEMPS REACHING ABOVE 0C WEST OF HIGHWAY 61. WINDS...ESPECIALLY EAST
OF HIGHWAY 61 WILL BE LIGHT...SO NOT MUCH MIXING WILL TAKE PLACE.
THIS WILL RESULT IN SUB FREEZING HIGHS GENERALLY EAST OF HIGHWAY
83...WHILE LOCATIONS WEST OF THIS ROUTE MAY REACH THE MID 30S TO
LOWER 40S IN THE EASTERN PANHANDLE.
LONG RANGE...FRIDAY NIGHT THROUGH TUESDAY...BEGINNING FRIDAY
NIGHT...RIDGING WILL BUILD EAST OF THE ROCKIES ONTO THE CENTRAL
PLAINS. MUCH WARMER H85 AIR WILL PUSH EAST WITH H85 TEMPS SAT
AFTERNOON OF 4 TO 8C. INHERITED FCST OF 40S TO LOWER 50S SATURDAY
ARE ON TRACK. A PACIFIC COOL FRONT WILL PUSH INTO THE FORECAST
AREA SUNDAY AFTERNOON. HIGHS WILL FALL BACK TO MORE SEASONAL
LEVELS SUNDAY...MONDAY AND TUESDAY. WITH THE FRONTAL
PASSAGE...THERE WILL BE A SMALL THREAT FOR RAIN OR SNOW SHOWERS
SUNDAY...FOLLOWED BY A SLIGHT CHANCE FOR SNOW ON SUNDAY NIGHT.
BEYOND TUESDAY...THE LATEST ECMWF AND GFS SOLNS DEVELOP A ZONAL
FLOW PATTERN NEXT WEEK WITH ARCTIC AIR WELL NORTH OF THE CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1122 PM CST TUE JAN 19 2016
THE MVFR/LOCAL IFR CIGS HAVE MOVE RAPIDLY EAST. IT IS QUITE
LIKELY VFR WOULD PREVAIL ALL AREAS FROM 15Z WEDNESDAY ONWARD.
SOME TIME WEDNESDAY EVENING...MVFR CIGS WILL DEVELOP FROM NORTH TO
SOUTH ASSOCIATED WITH A STRONG COLD FRONT. SNOW MAY BE UNDERWAY
ACROSS SHERIDAN COUNTY LATE WEDNESDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST /8 AM MST/ WEDNESDAY FOR
NEZ005>010.
&&
$$
UPDATE...CDC
SYNOPSIS...BUTTLER
SHORT TERM...MASEK
LONG TERM...BUTTLER
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1231 AM CST WED JAN 20 2016
.UPDATE...
ISSUED AT 1230 AM CST WED JAN 20 2016
VISIBILITIES HAVE LOWERED TO 1/4 MILE OVER NORTHWESTERN AND NORTH
CENTRAL NORTH DAKOTA WITHIN THE BOUNDARIES OF THE DENSE FOG
ADVISORY. OTHER AREAS...MAINLY SOUTH CENTRAL NORTH DAKOTA...HAVE
REDUCED VISIBILITIES OF 1/2 TO 2 MILES OR MORE BUT EXPECT
DETERIORATING VISIBILITIES THERE AS WELL. CURRENT DENSE FOG ADVISORY
LOOKS VALID FOR THE MORNING HOURS. ONLY OTHER CONCERN WAS
TEMPERATURES...AS TEMPERATURES IN THE NORTHWEST HAVE LOWERED MORE
THAN EXPECTED...AND HAD TO ADJUST LOWS TO AROUND ZERO OR BELOW IN A
LARGE AREA MAINLY EXTENDING FROM CROSBY TO BEULAH/HAZEN. CONFIDENCE
IS LOW REGARDING HOURLY TEMPERATURE TRENDS...AS SOME AREAS TEMPS ARE
GOING DOWN AND OTHER AREAS (JAMES VALLEY) WITH SOUTH WINDS AND
TEMPERATURES ARE FAIRLY STEADY. SHORT TERM MODELS DO NOT HAVE THIS
DETAIL IN THEIR OUTPUTS.
UPDATE ISSUED AT 826 PM CST TUE JAN 19 2016
QUICK UPDATE TO EXPAND THE DENSE FOG ADVISORY INTO
MCKENZIE...DUNN...GRANT AND SIOUX COUNTIES PER OBSERVED TRENDS
0230 UTC.
UPDATE ISSUED AT 721 PM CST TUE JAN 19 2016
WEBCAM AND SURFACE OBSERVATION TRENDS THROUGH 0115 UTC DEPICT
VISIBILITY RAPIDLY FALLING ACROSS NORTHWEST AND INTO CENTRAL NORTH
DAKOTA WITH STRATUS BUILD DOWN. THUS...HAVE ISSUED A DENSE FOG
ADVISORY FOR THESE AREAS THROUGH 16 UTC WEDNESDAY MORNING. THE
SPATIAL COVERAGE OF THE ADVISORY IS FITTED TO CURRENT AREAS WITH
DENSE FOG...EXTRAPOLATED TO VISIBILITY TRENDS IN THE 21-00 UTC
HRRR ITERATIONS. A POTENTIAL EXPANSION OF THE ADVISORY IS
POSSIBLE LATER THIS EVENING.
UPDATE ISSUED AT 637 PM CST TUE JAN 19 2016
GIVEN TRENDS IN THE 21-23 UTC HRRR ITERATION VISIBILITY FORECASTS...EXPANDED
THE MENTION OF FOG TO ALL OF WESTERN AND CENTRAL NORTH DAKOTA
TONIGHT INTO WEDNESDAY MORNING. PATCHY DENSE FOG HAS ALREADY
DEVELOPED ACROSS NORTHWEST NORTH DAKOTA AS OF 00 UTC...AND EXPECT
A SLOW EXPANSION OF FOG WITH STRATUS BUILD DOWN THROUGH THE NIGHT.
A DENSE FOG ADVISORY MAY BE NEEDED.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
LOOKS LIKE THE VERY COLD AIR WILL TAKE AN EXIT FOR AWHILE.
CONCERNS NOW FOR THIS SHORT TERM PERIOD WILL FOCUS ON THE
POTENTIAL FOR FOG TONIGHT. MESOSCALE MODELS HAVE BEEN CONSISTENTLY
FORECASTING A SHALLOW COOL AND MOIST BOUNDARY LAYER FREE OF
CLOUDS ABOVE. HRRR DEVELOPS WIDESPREAD LOW VISIBILITIES THIS
EVENING AND OVERNIGHT.
SATELLITE TRENDS SO FAR TODAY SHOW THE STRATUS LAYER ERODING
IN LOW LEVEL WARM ADVECTION ACROSS WESTERN NORTH DAKOTA. THIS
PROCESS WILL BE DISRUPTED THIS EVENING AS SUNSET APPROACHES.
DURING THE COOLING HOURS IN THE EVENING EXPECT FOG TO FORM IN THE
CLEARING ZONE WITH THE CLOUDS CREEPING BACK WEST. THIS WILL MAKE
MIN TEMPERATURES IN THE CLEARING AREA A CHALLENGE. SO FAR HAVE
ACCEPTED THE CONSSHORT GUIDANCE GIVING LOWER TEENS ACROSS THE
WEST AND SINGLE DIGITS ABOVE ZERO EAST.
ON WEDNESDAY THE NEXT SHORTWAVE IN A SERIES OF SHORTWAVES WILL
BRING AN INCREASE IN MID/HIGH CLOUDS AND BREAK OF THE BOUNDARY LAYER
FOG DURING FORENOON. A SLIGHT CHANCE OF SNOW SEEMS REASONABLE BY
LATE AFTERNOON FAR WEST. HIGH WEDNESDAY IN THE 20S TO MID 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 229 PM CST TUE JAN 19 2016
WEDNESDAY NIGHT THROUGH THURSDAY...COLD AIR ADVECTION AND A CHANCE
OF LIGHT SNOW WILL BEGIN POURING INTO SOUTHWEST NORTH DAKOTA
WEDNESDAY EVENING AS A SURFACE LOW AND ASSOCIATED MID LEVEL
SHORTWAVE SCOOT FROM SOUTHEAST MONTANA INTO SOUTH DAKOTA. THIS WILL
BE FOLLOWED BY ANOTHER SHORTWAVE THURSDAY...AS IT MOVES FROM WEST TO
EAST DURING THE DAY. THERE HAD BEEN SOME CONCERN FOR LIGHT FREEZING
RAIN WEDNESDAY EVENING...BUT THE NAM/SREF/GFS BUFKIT SOUNDINGS
INDICATE THAT IF IT DID DEVELOP...IT WOULD BE BRIEF...WITH A FAIRLY
QUICK TRANSITION TO LIGHT SNOW. NOT SEEING AN EXTENDED PERIOD OF
UPWARD VERTICAL MOTION WITH WITHIN THE SUPERCOOLED WATER DROPLET
REGIME...AND THE TRANSITION TIME FOR ANY GIVEN SOUNDING TO REACH
COLDER/HIGHER LEVELS OF SATURATION IS ACHIEVED FAIRLY QUICKLY
WEDNESDAY NIGHT. THUS...GIVEN THE BRIEF TIME AND ISOLATED COVERAGE
OF LIGHT FREEZING RAIN POTENTIAL...HAVE DECIDED TO STICK WITH THE
GIVEN FORECAST WHICH KEEPS A MENTION OF ONLY LIGHT SNOW. WILL
REVISIT THE SOUNDINGS AGAIN TONIGHT AND WEDNESDAY FOR ANY
SIGNIFICANT CHANGES TO THE ABOVE THINKING. OTHERWISE...CHANCES FOR
LIGHT SNOW WILL EXPAND INTO CENTRAL NORTH DAKOTA THROUGH THE DAY
THURSDAY. SNOWFALL ACCUMULATIONS THROUGH THURSDAY EVENING ARE
FORECAST AROUND A HALF INCH WEST AND CENTRAL...WITH AN ISOLATED SPOT
OF ONE INCH IN THE SOUTHWEST. THE CHANCE OF LIGHT SNOW EXITS THE
SOUTHERN JAMES RIVER VALLEY THURSDAY EVENING. WITH ONGOING COLD AIR
ADVECTION...HIGH TEMPERATURES THURSDAY WILL BE 5 TO 10 DEGREES
COLDER FROM WEDNESDAY...WHICH PUTS HIGHS THURSDAY FROM AROUND 10F
ABOVE IN THE TURTLE MOUNTAINS TO 25F SOUTHWEST.
THURSDAY NIGHT THROUGH SATURDAY...FOLLOWING THE ABOVE SHORTWAVE IS
AN UPPER LEVEL RIDGE WHICH WILL SHIFT FROM THE NORTHERN ROCKIES INTO
THE NORTHERN HIGH PLAINS FRIDAY INTO MOST OF SATURDAY. STRONG LOW
LEVEL WARM AIR ADVECTION FRIDAY AND SATURDAY WILL RESULT IN A
MODERATING TREND ALONG WITH DRY CONDITIONS. HIGHS FRIDAY WILL RANGE
FROM AROUND 20 IN THE JAMES RIVER VALLEY TO 40 WEST. BY SATURDAY
HIGHS WILL RANGE BETWEEN 30F AND 40F ACROSS WESTERN AND CENTRAL
NORTH DAKOTA.
THE WARMING TREND WILL COME TO AN END SATURDAY EVENING...AS A COLD
FRONT SWEEPS FROM NORTHWEST TO SOUTHEAST. THIS LEADS TO A CHANCE OF
SNOW AND COLDER TEMPERATURES SUNDAY. HIGHS SUNDAY THROUGH TUESDAY
ARE NEARLY THE SAME EACH DAY WITH HIGHS IN THE UPPER TEENS IN THE
TURTLE MOUNTAINS TO 20S ELSEWHERE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1230 AM CST WED JAN 20 2016
WIDESPREAD LIFR/VLIFR CONDITIONS IN FOG AND STRATUS EXPANDING ACROSS
WESTERN AND CENTRAL NORTH DAKOTA THROUGH WEDNESDAY MORNING. AFTER A
BRIEF RETURN TO VFR CONDITIONS AT SOME LOCATIONS WEDNESDAY
AFTERNOON...EXPECT MVFR CONDITIONS AGAIN WEDNESDAY EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM CST /9 AM MST/ THIS MORNING FOR
NDZ001-002-009>011-017>023-034>036-042-045>047-050.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...KS
AVIATION...JV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 AM EST WED JAN 20 2016
.SYNOPSIS...
AN UPPER LEVEL TROUGH ALONG WITH AN UPPER LEVEL DISTURBANCE
WILL COMBINE TO BRING SNOW TO THE AREA WEDNESDAY. HIGH PRESSURE
AND DRY AIR WILL RETURN FOR THURSDAY...UNTIL A LARGE AREA OF LOW
PRESSURE BRINGS ANOTHER WINTER SYSTEM TO THE REGION ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HIGH CLOUDS ARE SPREADING INTO THE FORECAST AREA THIS
EVENING...AND RADAR ECHOES HAVE EXTENDED INTO SOUTHWEST INDIANA.
SOME OF THESE ECHOES ARE VIRGA...WITH THE INITIAL AREAS OF SNOW
JUST NOW REACHING SOUTHERN ILLINOIS. BASED ON CURRENT TRENDS AND
RECENT HRRR/RAP FORECAST CYCLES...THE TIMING FOR SNOW WAS SPED UP
SLIGHTLY. ALSO...POPS WERE INCREASED TO 100 PERCENT FOR MUCH OF
THE FORECAST AREA.
THE LATEST GUIDANCE SUGGESTS THAT THE CURRENT SNOWFALL FORECAST IS
STILL ON TRACK...FALLING VERY CLOSE TO THE SREF MEAN...AND IN
BETWEEN THE HIGHER NAM AND LOWER RAP SOLUTIONS.
PREVIOUS DISCUSSION >
CURRENTLY MOSTLY CLEAR SKIES WITH SOME PASSING CIRRUS AS THE NEXT
UPPER LEVEL SYSTEM CAN CLEARLY BE SEEN ON VISIBLE OFF TO OUR WEST.
WEDNESDAY MORNING AN UPPER LEVEL TROUGH WILL DIVE SOUTHEAST AND
PUSH INTO OUR FAR WESTERN ZONES BETWEEN 4 AM AND 7 AM. OMEGA
VALUES ON BOTH THE GFS AND NAM SHOW WEAK LIFT MOVING ACROSS THE
AREA RIGHT AROUND 6 AM ALONG WITH ISENTROPIC UPGLIDE COMMENCING.
THINK THE ONSET OF SNOW MIGHT BE DELAYED A BIT AS GFS AND NAM
FORECAST SOUNDINGS SHOW DRY AIR AROUND 750 MB SLOWLY ERODING
WEDNESDAY MORNING. THIS MAKES SENSE AS 12 Z 700 MB ANALYSIS SHOWED
DEWPOINT DEPRESSIONS OF GREATER THAN 20 DEGREES JUST OFF TO OUR
WEST.
LATEST SUITE OF HIGH RES AND GLOBAL MODELS HAVE SHOWN A SLIGHT
INCREASE IN AMOUNTS OF SNOWFALL ACROSS THE AREA BUT AM EXPECTING 1-2
INCHES WITH HIGHER AMOUNTS POSSIBLE ACROSS THE SOUTHWEST OF THE CWA.
THE TIMING OF THE SNOWFALL ALSO LOOKS TO OCCUR DURING THE MORNING
COMMUTE. GIVEN THE POTENTIAL IMPACTS DURING THE MORNING COMMUTE
AND SLIGHTLY HIGHER TOTALS HAVE EXTENDED THE WINTER WEATHER ADVISORY
ONE TIER OF COUNTIES NORTH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
WEDNESDAY MORNING WILL START OFF WITH SNOW SPREADING ACROSS THE
CWA WITH HIGHER TOTALS FORECASTED ACROSS THE SOUTHERN PARTS OF THE
FORECAST AREA. FORECAST SOUNDINGS ON THE NAM AND GFS THEN SHOW
THE SNOW STARTING TO COME TO AN END WEST TO EAST BETWEEN NOON AND
2 PM. ACROSS OUR FAR EASTERN COUNTIES SNOW SHOULD COME TO AN END
BY 7 PM. FORECAST SOUNDINGS ON BOTH THE GFS AND NAM ALSO SHOW DRY
AIR STARTING TO MOVE IN AT 500 MB AS THE MAIN SHORTWAVE MOVES
OVERHEAD. THE DGZ APPEARS TO BE BETWEEN 550 AND 700 MB. THE
DEWPOINT AND TEMPERATURE LINES ON THE FORECAST SOUNDINGS CONTINUE
TO PULL APART IN THE AFTERNOON. THIS WILL BRING AN END TO THE
SNOW. THE TEMPERATURE PROFILE IS ALSO ISOTHERMAL RIGHT AROUND -10
DEGREES FROM 900 TO 700 MB. A LITTLE COLDER PROFILE WILL KEEP THE
SNOW GOING SLIGHTLY LONGER AS ICE CRYSTALS WILL BE ABLE TO GROW
WHERE AS A SLIGHTLY WARMER PROFILE WOULD FAVOR A QUICKER END TO
THE SNOW AND A POSSIBLE BRIEF PERIOD OF DRIZZLE. FOR NOW HAVE LEFT
THE MENTION OF DRIZZLE OUT AS CONFIDENCE REMAINS LOW.
WEDNESDAY EVENING SNOW WILL COME TO AN END AS A WEAK COLD FRONT
CROSSES THE AREA. SURFACE HIGH PRESSURE WILL THEN MOVE OVERHEAD
THURSDAY MORNING ALLOWING WINDS TO GO CALM. THURSDAY MORNING THE
GFS... EURO AND NAM ALL SHOW A CIRRUS SHIELD MOVING IN FROM THE
SOUTHWEST ALONG WITH SOME LOW CLOUDS LINGERING. GIVEN THE ABOVE...
LOW TEMPERATURES THURSDAY MORNING WILL LIKELY BE A TAD WARMER
THAN WEDNESDAY MORNINGS TEMPS. DURING THE DAY THURSDAY CIRRUS WILL
CONTINUE WITH SURFACE RIDGING WEAKENING ACROSS THE AREA AS THE
NEXT SYSTEM APPROACHES FROM THE WEST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
MAIN FOCUS IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR A
WINTER STORM TO AFFECT THE OHIO VALLEY REGION. THE IMPETUS FOR WHAT
WILL DEVELOP INTO A CLOSED MID LEVEL CIRCULATION EITHER OVER THE TN
VLY OR THE DEEP SOUTH IS STILL OFF THE WEST COAST ATTM...SO CAUTION
MUST BE USED IN THE FORECAST DUE TO THE OSCILLATIONS IN THE POSITION
AND TRACK OF THE MID LEVEL CIRCULATION. MODELS TEND TO HAVE ISSUES
WITH THE CLOSING OFF OF SUCH SYSTEMS...AND GIVEN THAT THE ENERGY IS
STILL OFF THE WEST COAST...THERE WILL BE TIME FOR OSCILLATIONS TO
CONTINUE UNTIL PERHAPS 12Z WEDNESDAY WHEN THE ENERGY WILL BE FULLY
SAMPLED.
THAT BEING SAID...OF THE MAIN OPERATIONAL MODELS FROM THE 01.19.12Z
RUN...THE ECMWF HAS TAKEN A MORE SOUTHERN TRACK ACROSS THE DEEP
SOUTH VERSUS THE OTHER MODELS (NAM...GFS...AND CMC). AS TO NOT JUMP
ON THE PURE 12Z ECMWF SOLUTION...WHICH WOULD BRING A PCPN SHIELD/MID
LEVEL DEFORMATION AXIS ONLY AS FAR NORTH AS THE OHIO RIVER...HAVE
TAKEN A BLEND OF THE 12Z GFS AND THE PREVIOUS 00Z ECMWF WHICH KEEPS
SOME CONTINUITY TO THE GOING FORECAST AND ALLOWS FOR SOME POTENTIAL
FOR A MORE NORTHERN TRACK TO BE A POSSIBLE SOLUTION. THUS...THE
CURRENT FORECAST WILL ALLOW PCPN SHIELD/MID LVL DEFORMATION AXIS
PUSH NORTHWARD TOWARD THE OHIO RIVER THURSDAY NIGHT...ALLOWING IT TO
PIVOT AS FAR NORTH/NORTHWEST AS THE I-71 CORRIDOR...AND THEN ALLOW
IT TO SHIFT EAST FRIDAY NIGHT INTO SATURDAY AS A COASTAL LOW/ENERGY
TRANSFER TAKES PLACE. BASED ON THIS SCENARIO...PCPN SHOULD REMAIN AS
SNOW WITH THE POTENTIAL FOR SIGNIFICANT SNOW ACCUMULATIONS ALONG AND
SOUTHEAST OF THE I-71 CORRIDOR AND PARTICULARY ALONG AND SOUTH OF
THE OHIO RIVER VALLEY. THUS...AT THIS JUNCTURE...4 OR MORE INCHES OF
SNOW MAY BE POSSIBLE ALONG AND SOUTH OF THE I-71 CORRIDOR WITH 6 OR
MORE INCHES POSSIBLE ALONG AND SOUTH OF THE OHIO RIVER. AGAIN...A
TRACK FARTHER SOUTH WOULD ONLY IMPACT LOCATIONS ALONG AND SOUTH OF
THE OHIO RIVER...AND A TRACK FARTHER NORTH WOULD PUSH THE THREAT
TOWARD THE I-71 CORRIDOR. AS THE COASTAL LOW TAKES SHAPE AND MOVES
NEAR AND OFF THE NEW ENGLAND COAST SATURDAY AFTERNOON AND
NIGHT...PCPN WILL TAPER OFF OVER THE REGION AS SURFACE HIGH PRESSURE
BUILDS BACK INTO THE OHIO VALLEY. AS FOR TEMPERATURES...HAVE TAKEN
BLEND OF PREVIOUS FORECAST AND THE 12Z GFS/00Z ECMWF. SOME
ADJUSTMENTS MAY HAVE TO BE MADE TO CURRENT VALUES DEPENDING ON WHERE
AND THE AMOUNT OF SNOW COVER WHICH MAY FALL...WHICH WILL HAVE AN
ALBEDO EFFECT/RADIATIONAL COOLING EFFECT.
FOR SUNDAY INTO MONDAY...HIGH PRESSURE WILL MOVE OFF TO THE EAST AS
THE NEXT LOW PRESSURE SYSTEM AND FRONT MOVE IN FROM THE WEST. THERE
ARE SOME TIMING AND STRENGTH DIFFERENCE AT THIS POINT...SO WILL
BRING A GRADUAL CHANCE OF PCPN FROM WEST TO EAST MONDAY AFTERNOON
INTO MONDAY NIGHT...WITH THE CHANCE CONTINUING INTO TUESDAY AS THE
SYSTEM MOVES THROUGH. TEMPERATURES WILL BE CRITICAL TO PTYPE.
CURRENTLY HAVE RAIN/SNOW FOR NORTHERN AREAS AND RAIN FOR SOUTHERN
AREAS...WITH A CHANGEOVER TO ALL SNOW ON TUESDAY IN THE WAKE OF THE
LOW AND FRONT. A BLEND OF THE TEMPERATURES HAVE BEEN USED WITH HIGHS
IN THE 30S TO AROUND 40 AND LOWS MAINLY IN THE 30S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
FAST MOVING STORM SYSTEM WILL BRING SNOW TO THE TAFS MAINLY
BETWEEN 10Z-18Z TODAY. WHEN THE SNOW ARRIVES...VSBYS WILL DROP TO
IFR...WITH MVFR CIGS EXPECTED.
BEHIND THE SNOW...MODELS ARE HOLDING LOW LEVEL MOISTURE AND IFR
CIGS PAST 00Z. NAM IS MOST ENTRENCHED WITH LOWS...HOLDING THEM ALL
THE WAY THROUGH 30 HOURS. OTHER MODELS ARE NOT QUITE AS
PESSIMISTIC...BUT WILL LEAN TOWARDS THE NAM...AS IT SEEMS THAT
THE LOW CLOUDS ARE SOMETIMES HARD TO GET OUT OF THE REGION THIS
TIME OF THE YEAR.
OUTLOOK...MVFR/IFR CONDITIONS ARE EXPECTED WITH PRECIPITATION ON
FRIDAY INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM
EST THIS EVENING FOR OHZ070>072-077>081-088.
KY...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM
EST THIS EVENING FOR KYZ089>100.
IN...WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 7 PM
EST THIS EVENING FOR INZ066-073>075-080.
&&
$$
SYNOPSIS...HAINES
NEAR TERM...HAINES/HATZOS
SHORT TERM...HAINES
LONG TERM...HICKMAN
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS Tulsa OK
1139 PM CST TUE JAN 19 2016
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Areas of freezing drizzle continue over portions of NE OK and NW
AR late this evening. The heavier precipitation will begin to
shift east of the region around 08z. Low clouds/fog however will
continue overnight and likely persist through much of the day
Wednesday as surface winds slowly return to the southeast.
&&
.PREV DISCUSSION... /ISSUED 909 PM CST TUE JAN 19 2016/
..UPDATE...
DISCUSSION...
Precipitation across far eastern OK and northwest AR has been
convection in nature...resulting in pockets of brief moderate
sleet/freezing rain this evening. This has made for very slick
conditions across the region...especially in and around the Fort
Smith area and into parts of Madison county. HRRR trends are for
the heavier precipitation to shift east of the region after
06z...although could see a few more hours of light freezing
drizzle. Will leave the winter weather advisory as is for
now...but it may end of being cancelled a bit earlier than 12z.
&&
.TSA Watches/Warnings/Advisories...
OK...Winter Weather Advisory until 6 AM CST Wednesday for OKZ057-058-
062-063-068-069-072.
AR...Winter Weather Advisory until 6 AM CST Wednesday for ARZ001-002-
010-011-019-020-029.
&&
$$
AVIATION...12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1154 PM CST TUE JAN 19 2016
.UPDATE...
FOR 06Z AVIATION DISCUSSION.
&&
.DISCUSSION...
LATEST SURFACE ANALYSIS DEPICTS SNOW ACROSS THE NORTHERN HALF OF
MO. FREEZING RAIN AND SOME SLEET OVER SRN MO...SOME FRZ RAIN
ACROSS NRN AR. 00Z OHX SOUNDING REVEALED 850 MB TEMPS THAT WERE
SLIGHTLY WARMER THAN THE MODELS. WET BULB ZERO PROFILES AT THE 850
MB LEVEL SHOWS A RATHER IMPRESSIVE WEDGE OF WARMING ACROSS AR.
PORTIONS OF NRN AR AND SRN MO SHOW FRZ RA WITH TEMPS IN THE LOWER
TO MID 20S...A TESTAMENT AS TO THE DEGREE OF WARM WEDGING THAT IS
ON GOING. SFC LOW IS CURRENTLY LOCATED OVER ERN OK. SLIGHT
INCREASE IN STRENGTH IS EXPECTED WITH THE WARM AIR IN THE 800MB TO
900 MB LEVEL WORKING EASTWARD. THIS WARMER AIR MAY VERY WELL MAKE
IT INTO OUR SOUTHWESTERN COUNTIES PRIOR TO 12Z. THUS...I WILL GO
AHEAD AND INCLUDE MORE IN THE WAY OF SLEET AND FREEZING RAIN
ACROSS OUR SOUTHWESTERN AND SOUTH CENTRAL AREAS.
LATEST HRRR SHOWS PATCHY LIGHT PRECIP MAKING IT ACROSS THE TN
RIVER AND REACHING THE GROUND JUST AFT MIDNIGHT. THE MORE
SIGNIFICANT PRECIP APPEARS TO MAKE IT ACROSS THE TN RIVER RIGHT
AROUND 6 AM. BASED ON THE LATEST 18Z NAM SOUNDINGS...IT STILL
LOOKS LIKE ALL SNOW NORTH OF I-40. BUT...THAT SOUTHWEST AREA IS A
CONCERN AND MORE IN THE WAY OF SLEET AND FREEZING RAIN COULD
FALL. AGAIN...WILL OPT TO MODIFY THE WX GRIDS TO REFLECT THIS
ACROSS SOUTHWEST AND SOUTH CENTRAL AREAS. SFC TEMPS STILL EXPECTED
TO WARM ABOVE FREEZING ACROSS THE SOUTHWEST BY 9AM...AND THEN ALL
BUT THE PLATEAU AREA BY NOON.
UPDATE OUT SHORTLY.
&&
.AVIATION...
06Z TAF DISCUSSION.
COMPLICATED AVIATION WX FORECAST SCENARIO WITH POTENTIAL ICING CONCERNS
DUE TO FROZEN PCPN DEVELOPMENT CONTINUES. LATEST SHORT RANGE MODEL
CONSENSUS CONTINUING TO SHOW THAT ORGANIZED FROZEN PCPN DEVELOPMENT BEGINS
BY 20/08Z...LASTING CKV/BNA THRU 20/18Z...WITH CONTINUANCE OF FROZEN PCPN
IMPACTING CSV THRU 21/00ZZ. BEST ICING WINDOW PER FREEZING RAIN POTENTIAL
CKV/BNA 20/13Z-20/18Z AND CSV 20/18Z-20/24Z. CKV/BNA SHOULD EXPERIENCE A
TRANSITION TO LIGHT RAIN 20/18Z-21/00Z. MOST OF MOISTURE EXPECTED TO MOVE
EAST OF MID STATE 21/00Z-21/06Z...BUT A WEAK DISTURBANCE IN NWLY FLOW ALOFT
BEFORE SUBTLE UPPER LEVEL RIDGING INFLUENCES BUILD INTO THE MID STATE MIGHT
RESULT IN LIGHT FREEZING DRIZZLE BNA/CKV 21/02Z-21/06Z. CURRENT VFR CEILINGS
ARE EXPECTED TO LOWER TO STRATUS MVFR CEILINGS 20/07Z CKV-20/12Z CSV.
CEILINGS WILL EVENTUALLY LOWER INTO IFR/LIFR THRESHOLDS 20/18Z-21/06Z.
EXPECT PCPN TO RESULT IN LOWERING CURRENT VFR VSBYS TO IFR 20/12Z-20/18Z
WITH SOME IMPROVEMENT TO MVFR VSBYS CKV/BNA 20/18Z-21/06Z.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM CST WEDNESDAY FOR BEDFORD-
CANNON-CHEATHAM-CLAY-COFFEE-CUMBERLAND-DAVIDSON-DE KALB-DICKSON-
FENTRESS-GILES-GRUNDY-HICKMAN-HOUSTON-HUMPHREYS-JACKSON-LAWRENCE-
LEWIS-MACON-MARSHALL-MAURY-MONTGOMERY-OVERTON-PERRY-PICKETT-
PUTNAM-ROBERTSON-RUTHERFORD-SMITH-STEWART-SUMNER-TROUSDALE-VAN
BUREN-WARREN-WAYNE-WHITE-WILLIAMSON-WILSON.
&&
$$
SHORT TERM/AVIATION........31
LONG TERM..................21
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1203 AM CST WED JAN 20 2016
.AVIATION...
NO SIGNIFICANT CHANGES TO PREVIOUS TAF PACKAGE. A WEAK COLD FRONT
IS STILL ON TAP TO CROSS THE FORECAST AREA DURING THE EARLY
MORNING HOURS. THE FRONT SHOULD MOVE ACROSS THE WESTERN TERMINALS
BETWEEN 08-10Z AND THE HOUSTON METRO AREA BETWEEN 11-14Z...AND
OFF THE COAST BETWEEN 15-18Z...RESULTING IN A N/NW WIND SHIFT.
ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ALONG AND
AHEAD OF THE FRONT AS IT SAGS SOUTHWARD. VFR CONDITIONS POSSIBLE
TOMORROW AFTERNOON TO THE NORTH OF I-10 BEHIND THE
FRONT...HOWEVER MVFR CIGS LIKELY TO REMAIN IN PLACE BETWEEN
HOUSTON METRO AREA AND THE COAST.
THE FRONT SHOULD STALL OUT NEAR THE COAST TOMORROW AFTERNOON
BEFORE IT BEGINS TO MOVE INLAND AS A WARM FRONT. MVFR/IFR CIG
CONDITIONS AND AREAS OF FOG LIKELY TOMORROW NIGHT BETWEEN CONROE
AND THE COAST. 44
&&
.PREV DISCUSSION... /ISSUED 914 PM CST TUE JAN 19 2016/
DISCUSSION...
SFC ANALYSIS AT 03Z SHOWED COLD FRONT STRETCHING FROM N TX THROUGH
W C TX WITH A FEW SHOWERS ALONG IT SE OF THE METROPLEX. BASED ON
LATEST HRRR TRENDS AND 00Z NAM...FRONT SHOULD CONTINUE TO PUSH
SOUTH INTO THE AREA THROUGH THE MORNING. FRONT MAY BE SLOW TO
RETURN NORTH AS A WARM FRONT TOMORROW.
STRONGER SHORT WAVE TROUGH PUSHES BY ON THURSDAY SO THINK THAT
WILL SUPPORT BETTER RAIN CHANCES AND PROBABLY SOME THUNDERSTORMS
GIVEN ENOUGH INSTABILITY. THAT SAID...MAY GET A DRY SLOT TO PUSH
THROUGH AND KICK STORMS EAST.
MAIN CHANGES TO THE FORECAST WERE TO UPDATE T/TD AS WELL AS
POP/WX/QPF FOR ONGOING TRENDS AND NEW MODEL GUIDANCE.
39
PREV DISCUSSION... /ISSUED 600 PM CST TUE JAN 19 2016/
AVIATION...
VFR CEILINGS THIS EVENING SHOULD GRADUALLY BECOME MVFR BETWEEN
06-09Z AS THE SOUTHERLY FLOW CONTINUES TO DRAW ADDITIONAL LOW
LEVEL MOISTURE IN TO THE AREA AHEAD OF AN APPROACHING COLD FRONT.
OVERNIGHT WINDS WILL BE LIGHT...BUT SHOULD PRODUCE ENOUGH MIXING
IN THE BOUNDARY LAYER TO INHIBIT WIDESPREAD FOG FORMATION.
A WEAK COLD FRONT SHOULD MOVE ACROSS THE WESTERN TERMINALS
BETWEEN 07-09Z AND THE HOUSTON METRO AREA BETWEEN 12-15Z...AND
OFF THE COAST BETWEEN 15-18Z...RESULTING IN A N/NW WIND SHIFT.
ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO DEVELOP ALONG AND
AHEAD OF THE FRONT AS IT SAGS SOUTHWARD...SO I CONTINUE TO CARRY A
VCSH MENTION FOR ALL TERMINALS. THE FRONT IS EXPECTED TO REACH THE
COAST...HOWEVER THE NORTH FLOW WILL BE SHORT LIVED AT TERMINALS TO
THE SOUTH OF I-10. WINDS SHOULD BECOME LIGHT AND VARIABLE OVER THE
HOUSTON METRO AREA AND VEER TO THE NORTHEAST AT TERMINALS CLOSER
TO THE COAST BY TOMORROW AFTERNOON. 44
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 45 60 54 65 38 / 30 10 30 40 10
HOUSTON (IAH) 53 66 57 70 41 / 20 30 30 50 10
GALVESTON (GLS) 58 63 59 69 44 / 20 30 10 40 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AVIATION/MARINE...44
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1058 AM EST WED JAN 20 2016
...HEAVY BAND OF PRECIP CURRENTLY PUSHING ACROSS FAR NORTH
GEORGIA COULD PRODUCE SOME LOCALLY HIGHER ICE ACCUMULATIONS TO
NEAR A QUARTER INCH WITHIN THE CURRENT WINTER STORM WARNING
AREA...
.UPDATE...
IMPRESSIVE BAND OF HEAVIER PRECIP IMPINGING INTO NW CWA WITH SOME
LIGHT MORE ISOLATED RETURNS AHEAD OF ASSOCIATED DISTURBANCE. SO
FAR HAVE HAD SOME REPORTS OF FZRA AND SLEET BUT MAINLY IN FAR
NORTH AND MAIN CONCERN OF IMPACTFUL ACCUMULATIONS WILL BE WITH
APPROACHING BAND AS EVAP COOLING MECHANISM HAS SHOWN SOME SFC TEMP
DROPS OF 2-3 DEG. GIVEN THE STILL LOW DWPTS ACROSS THE FAR
NORTHERN TIER WITH VALUES STILL IN UPPER TEENS TO LOW 20S AT SOME
SPOTS...COULD SEE SOME ISOLATED HIGHER ICE ACCUMULATIONS AROUND
0.25 INCHES. ALSO THE HRRR SO FAR LOOKS TO HAVE DECENT HOLD ON
TRENDS WITH P-TYPE AND HAVE ADJUSTED POPS AND WINTER GRIDS
ACCORDINGLY. HRRR PROGGED WETBULB TEMPS KEEP THE NE HIGHER
ELEVATIONS AROUND 30 DEG THROUGH THE AFTERNOON ALONG WITH A
TRANSITION FROM INITIAL MIXED P-TYPE TO PRIMARILY SNOW SO HAVE
INCREASED THE LOWER BOUND SNOW AMOUNTS TO NEAR HALF AN INCH
SLIGHTLY FARTHER SOUTHEAST TO NEAR GAINESVILLE AND EASTWARD. AS
FAR AS NEAR THE METRO...OVERNIGHT TEMPS WERE THANKFULLY ABOUT 4
DEGREES WARMER THAN FCST SO TRENDS HAVE BEEN TO RISE TO 34-36
DEGREES FROM THE WEST. ALL IN ALL HAVE NOT ADJUSTED ANY EXTENT OR
TIMING TO THE CURRENT ADVISORY AND WARNING AREAS. PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
.PREV DISCUSSION... /ISSUED 652 AM EST WED JAN 20 2016/
PREV DISCUSSION... /ISSUED 437 AM EST WED JAN 20 2016/
.SHORT TERM /TODAY THROUGH THURSDAY/...
SHORT TERM FORECAST CONTINUES TO BE A CHALLENGE WITH IMPACTFUL
WINTRY PRECIPITATION EXPECTED ACROSS NORTH GEORGIA. UPPER LEVEL
DISTURBANCE WILL INTERACT WITH COLD AND DRY CONDITIONS ACROSS THE
AREA TO PRODUCE A WINTRY MIX OVER PORTIONS OF NORTH GEORGIA.
ALTHOUGH MODELS HAVE SLOWED THE ONSET TIMING SLIGHTLY BY AN HOUR OR
SO...CONSENSUS IS THAT PRECIPITATION WILL BEGIN AS SNOW THIS
MORNING...THEN TRANSITION TO FREEZING RAIN/SLEET AND THEN TRANSITION
TO ALL SNOW IN THE NE MOUNTAINS BY THE AFTERNOON. ACCUMULATING
WINTRY MIX IS EXPECTED AS FAR SOUTH AS PORTIONS OF THE NORTHERN
ATLANTA SUBURBS...BUT STILL COULD SEE SOME NON-ACCUMULATING MIX AS
FAR SOUTH AS I-20. ALREADY SEEING SOME LIGHT RETURNS ON RADAR ACROSS
AL/NORTHERN GEORGIA...BUT SO FAR NOTHING REACHING THE GROUND.
MODELS CONTINUE TO SUGGEST THIS TO BE AN OVERALL LOW QPF
EVENT...WITH LIQUID EQUIVALENT ONLY A QUARTER INCH OR LESS. WPC WWD
GUIDANCE HAS BACKED OFF SOMEWHAT ON SNOWFALL TOTALS...BUT HAS SPREAD
THE ACCUMULATING FREEZING RAIN AMOUNTS FARTHER SOUTH. GIVEN THE
TIMING OF THE PRECIPITATION ONSET AND THE EXPECTED WARMING
TEMPERATURES /PARTICULARLY ACROSS THE METRO AREA/ HAVE OPTED NOT TO
DEVIATE TOO FAR FROM THE PREVIOUS SNOW/ICE AMOUNTS PREVIOUSLY
FORECAST...A LITTLE MORE CONSERVATIVE IN AREAL COVERAGE THAN THE WWD
ICE GRID.
THE WINTER STORM WARNING AND THE WINTER WEATHER ADVISORY CONTINUE
WITH NO CHANGES MADE TO THE TIMING OR AREA. STILL ANTICIPATE UP TO 2-
2.5 INCHES OF SNOW IN THE WSW /PARTICULARLY IN THE NE GA MOUNTAINS/
AND UP TO A TENTH OF AN INCH OF ICE. IN THE ADVISORY AREA UP TO 1
INCH OF SNOW AND A TENTH OF AN INCH OF ICE CAN BE EXPECTED. WITH
COLD ANTECEDENT CONDITIONS...IMPACTS ARE EXPECTED AT ONSET OF THE
PRECIPITATION. HAVE ALSO CONTINUED THE SPECIAL WEATHER STATEMENT FOR
SEVERAL COUNTIES JUST SOUTH OF THE ADVISORY AREA TO INDICATE
POTENTIAL FOR WINTRY PRECIPITATION MIXED WITH RAIN.
THERE REMAINS SEVERAL UNCERTAINTIES WITH THE FORECAST THAT WILL NEED
TO BE MONITORED AS THE EVENT UNFOLDS. THE WEAKENING RIDGE AND
EROSION OF THE ASSOCIATED LOW LEVEL INVERSION WILL PLAY A KEY ROLE
IN DURATION OF WINTER PRECIP. THERMODYNAMIC TRENDS WILL STILL NEED
TO BE WATCHED FOR WETBULBING/EVAPORATIVE COOLING EFFECTS AND IF IT
DELAYS THE TRANSITION TO OTHER P-TYPES. LINGERING FREEZING
TEMPERATURES INTO THE OVERNIGHT HOURS COULD ALLOW FROZEN PRECIP TO
CONTINUE AND INCREASE BLACK ICE THREAT.
STAY TUNED AS THE FORECAST CONTINUES TO EVOLVE AS THE EVENT UNFOLDS.
ALTHOUGH THE PRECIPITATION POTENTIAL DIMINISHES SOMEWHAT
OVERNIGHT...ALL RAIN WILL RETURN TO THE AREA THURSDAY AND INTO THE
INITIAL EXTENDED FORECAST PERIODS. ANTICIPATE THAT BY MID MORNING
THURSDAY ALL OF NORTH AND CENTRAL GEORGIA SHOULD BE SEEING ABOVE-
FREEZING TEMPERATURES.
31
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
SOUTHERN STREAM LOW MOVING INTO THE LOWER MS VALLEY AT THE START
OF THE PERIOD...TRACKING THROUGH THE TN VALLEY AND THEN OFF THE
MID ATLANTIC COAST BY SATURDAY MORNING. EXPECTING ALL LIQUID
PRECIP UNTIL FRIDAY NIGHT AS WRAP AROUND MOISTURE SPREADS INTO THE
FORECAST AREA. PARTIAL THICKNESS VALUES WOULD SUPPORT SNOW FOR THE
FAR NORTH AND A MIX OF RAIN AND SNOW FOR THE REMAINDER OF NORTH.
FOR NOW...HAVE KEPT LIGHT ACCUMULATIONS CONFINED TO THE FAR NORTH
SINCE ACTUAL QPF IS STILL QUESTIONABLE. SOME LIGHT WRAP AROUND SNOW
IS POSSIBLE SATURDAY FOR THE EXTREME NORTH AS THE LOW CONTINUES TO
MOVE NORTHEAST. SUNDAY LOOKS DRY BUT THE NEXT LOW IS MOVING INTO
THE MID MS VALLEY BY MONDAY...BRINGING MOISTURE BACK INTO THE
FORECAST AREA. PRECIPITATION SHOULD SPREAD ACROSS NORTH AND
CENTRAL GEORGIA MONDAY AND TUESDAY. LOOKING FOR ALL RAIN MONDAY
AND TUESDAY...HOWEVER LEADING INTO TUESDAY NIGHT THERE IS ANOTHER
CHANCE FOR SOME FREEZING OR FROZEN PRECIP ACROSS FAR NORTH
GEORGIA.
41
&&
.AVIATION...
12Z UPDATE...
VFR CONDITIONS THIS MORNING WILL DEGRADE TO MVFR AT THE NORTHERN
TAF SITES BY LATE AFTERNOON WITH -SHRA BEGINNING. -DZ EXPECTED
OVERNIGHT AND CIGS WILL DEGRADE TO IFR. AS -RA RETURNS THURSDAY
MORNING CIGS WILL REMAIN IFR. SE WINDS WILL BECOME SW 18-21Z /OR
POSSIBLY LATER/ THEN SHIFT BACK TO THE E-SE BY THIS
EVENING/OVERNIGHT. SPEEDS GENERALLY 7KT OR LESS. AT SOUTHERN TAF
SITES CIGS WILL DEGRADE TO MVFR BY 10-11Z THURSDAY.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON PRECIPITATION TIMING. HIGH CONFIDENCE ON ALL OTHER
ELEMENTS.
31
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 41 33 43 38 / 40 30 70 90
ATLANTA 42 37 47 42 / 40 40 70 90
BLAIRSVILLE 35 31 45 36 / 80 40 70 90
CARTERSVILLE 38 33 46 40 / 70 40 70 90
COLUMBUS 50 43 59 49 / 20 40 60 90
GAINESVILLE 35 32 42 37 / 60 40 70 90
MACON 50 40 54 45 / 20 30 50 70
ROME 37 34 46 41 / 80 40 80 90
PEACHTREE CITY 44 35 49 43 / 40 40 70 90
VIDALIA 54 41 57 47 / 5 10 30 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR THE FOLLOWING
ZONES: CATOOSA...CHATTOOGA...DADE...DAWSON...FANNIN...GILMER...
GORDON...LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...WALKER...
WHITE...WHITFIELD.
WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR THE
FOLLOWING ZONES: BANKS...BARTOW...CHEROKEE...FLOYD...FORSYTH...
HALL.
&&
$$
SHORT TERM...31/BAKER
LONG TERM....41
AVIATION...31
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1030 AM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL
DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST.
THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH
PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR
THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL
LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH
MOVING INTO THE FORECAST AREA. THE LATEST HRRR INDICATES
PRECIPITATION DIMINISHING AS IT MOVES INTO THE AREA FROM THE WEST
LATE THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF THE FORECAST
AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE
PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE
DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE
GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO
10 TO 20 PERCENT SOUTH LATER THIS AFTERNOON. THE TOP-DOWN METHOD
RUN ON BOTH THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND
SNOW CLOSE TO THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A
RAIN AND SNOW MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED
ON THE WET BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE
RIDGE. FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA.
NO SIGNIFICANT IMPACTS ARE EXPECTED BECAUSE OF LIGHT AMOUNTS AND
MARGINAL TEMPERATURES. LOWERED AFTERNOON HIGHS A BIT DUE TO A
COLD START...CLOUDINESS...AND THE EVAPORATIVE COOLING POTENTIAL.
MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH
THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE
LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED
A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC
WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. THE PREVIOUS NAM MOS INDICATED A 40 PERCENT POP IN THE
SOUTH PART LATE TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A
MID-LEVEL SHORTWAVE TROUGH...WITH THE LATEST NAM MOS INDICATING
MUCH LOWER POPS. WILL KEEP A SMALL POP IN THE SOUTH PART FOR
TONIGHT. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB TEMPERATURES
ABOVE FREEZING IN THE SOUTH PART DURING THE PRECIPITATION CHANCE
TIME INDICATED BY THE NAM. USED THE GUIDANCE CONSENSUS FOR THE
TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST
ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS
ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING
ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE
AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE
DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW
PRESSURE SYSTEM LIFTS NORTHEAST.
MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS
THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY
BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD
COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE
1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF
SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL
MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS
REMAINS A LOW CONFIDENCE FORECAST.
WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY
RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE
EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON
INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS
AFTERNOON INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A
DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE
WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE.
HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR
CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR-
SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH
THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS
AFTERNOON WITH THE AXIS JUST EAST OF THE AREA.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
623 AM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
THROUGH TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER-
LEVEL DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE
WILL INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE
WEST. THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT.
DRY HIGH PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE SURFACE RIDGE IN THE FORECAST AREA THIS MORNING WILL BE NEAR
THE COAST THIS AFTERNOON. THE RIDGE AND H85 WESTERLY FLOW WILL
LIMIT MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH
MOVING INTO THE FORECAST AREA. THE HRRR...ARW AND SPC WRF
INDICATE PRECIPITATION DIMINISHING AS IT MOVES INTO THE AREA
FROM THE WEST LATE THIS AFTERNOON INTO THE EVENING. EXPECT MUCH OF
THE FORECAST AREA WILL HAVE A PERIOD OF SPRINKLES BUT THE CHANCE
OF MEASURABLE PRECIPITATION SHOULD BE LOW. THE GFS AND NAM PLUS
SREF GUIDANCE DISPLAY PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR
LESS. THE GUIDANCE CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME
NORTH TO 10 TO 20 PERCENT SOUTH. THE TOP-DOWN METHOD RUN ON BOTH
THE NAM AND GFS CONFINE PATCHES OF MIXING RAIN AND SNOW CLOSE TO
THE NORTH CAROLINA BORDER. HOWEVER...WE INCLUDED A RAIN AND SNOW
MIX FARTHER SOUTH THAN INDICATED BY THE MODELS BASED ON THE WET
BULB POTENTIAL COOLING ASSOCIATED WITH THE SURFACE RIDGE.
FORECASTED SNOW POSSIBLE JUST NORTH AND WEST OF COLUMBIA. NO
SIGNIFICANT IMPACTS ARE EXPECTED BECAUSE OF LIGHT AMOUNTS AND
MARGINAL TEMPERATURES. THE GUIDANCE TEMPERATURES ARE LIKELY TOO
HIGH TODAY BECAUSE OF A COLD START...CLOUDINESS...AND THE EVAPORATIVE
COOLING POTENTIAL.
MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL SHORTWAVE TROUGH
THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS INDICATE
LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE. FORECASTED
A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND SPC
WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. THE NAM MOS DID INDICATE A 40 PERCENT POP IN THE SOUTH PART
LATE TONIGHT ASSOCIATED WITH THE FRONT AND AHEAD OF A MID-LEVEL
SHORTWAVE TROUGH. THE GFS AND ECMWF MOS INDICATED A LOWER POP.
USED AN AVERAGE OF THE GUIDANCE AND FORECASTED A SMALL POP IN THE
SOUTH PART. BOTH THE NAM AND GFS HAVE SURFACE WET-BULB
TEMPERATURES ABOVE FREEZING IN THE SOUTH PART DURING THE
PRECIPITATION CHANCE TIME INDICATED BY THE NAM. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST
ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS
ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING
ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE
AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE
DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW
PRESSURE SYSTEM LIFTS NORTHEAST.
MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS
THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY
BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD
COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE
1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF
SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL
MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS
REMAINS A LOW CONFIDENCE FORECAST.
WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY
RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE
EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON
INTO TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS
AFTERNOON INTO THE EVENING. THE ARW...HRRR...AND SPC WRF DISPLAY
A DIMINISHING AREA OF PRECIPITATION MOVING INTO THE AREA FROM THE
WEST DURING THAT TIME ASSOCIATED WITH THE UPPER-LEVEL FEATURE.
HOWEVER...ALL THE GFS AND NAM MOS PLUS SREF GUIDANCE INDICATE VFR
CONDITIONS AND BELIEVE THIS IS REASONABLE BASED ON THE DRY NEAR-
SURFACE LAYER ASSOCIATED WITH THE RIDGE. WINDS WILL BE LIGHT WITH
THE RIDGE AXIS NEAR THE AREA...BUT BE MAINLY SOUTHWEST THIS
AFTERNOON WITH THE AXIS JUST EAST OF THE AREA. USED THE GFS LAMP
FOR THE WIND FORECAST.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY THROUGH SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1003 AM CST WED JAN 20 2016
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* LINGERING LIGHT SNOW/FLURRIES OVER THE NEXT 1-2 HOURS.
* MVFR CIGS REDEVELOPING.
KJB/RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
THE ACCUMULATING SNOW HAS COME TO AN END. HOWEVER...A FEW
LINGERING FLURRIES COULD LINGER FOR THE NEXT FEW HOURS...BUT NO
IMPACTS ARE EXPECTED. OTHERWISE...IT APPEARS THAT A PERIOD OF VFR
CIGS OF 4-6 KFT AGL WILL BE THE RULE FOR THE NEXT FEW
HOURS...BEFORE SOME LOWER MVFR CIGS REDEVELOP OVER THE AREA BY
LATE MORNING. THESE LOWER CIGS COULD HANG ACROSS MUCH OF THE AREA
THROUGH THE DAY.
THERE IS A SMALL CHANCE OF SOME FOG DEVELOPMENT LATE
TONIGHT...PARTICULARLY AT KRFD AND KDPA. HOWEVER...THERE IS
UNCERTAINTY DUE TO THE POSSIBILITY OF CLOUD COVER. THEREFORE...I
HAVE LEFT THE MENTION OUT OF THE TAFS AT THIS TIME.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH WITH SNOW TRENDS.
* MEDIUM WITH CEILING TRENDS.
KJB/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS.
FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY
NORTHEAST WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR.
TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
KJB
&&
.MARINE...
100 AM CST
SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT
WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY
FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE
SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS
AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE
UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER
NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE
LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT
ADVISORY FOR THE ILLINOIS AND INDIANA NEAR SHORES.
HOWEVER...THERE ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR
SHORES DUE TO THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO
BE MONITORED OVER THE NEXT COUPLE DAYS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
813 AM CST WED JAN 20 2016
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LINGERING LIGHT SNOW OVER THE NEXT 1-2 HOURS...LOWEST VIS IN THE
3-5SM RANGE.
* MVFR CIGS REDEVELOPING BY LATE MORNING AND CONTINUING INTO THE
AFTERNOON.
KJB/RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
THE ACCUMULATING SNOW HAS COME TO AN END. HOWEVER...A FEW
LINGERING FLURRIES COULD LINGER FOR THE NEXT FEW HOURS...BUT NO
IMPACTS ARE EXPECTED. OTHERWISE...IT APPEARS THAT A PERIOD OF VFR
CIGS OF 4-6 KFT AGL WILL BE THE RULE FOR THE NEXT FEW
HOURS...BEFORE SOME LOWER MVFR CIGS REDEVELOP OVER THE AREA BY
LATE MORNING. THESE LOWER CIGS COULD HANG ACROSS MUCH OF THE AREA
THROUGH THE DAY.
THERE IS A SMALL CHANCE OF SOME FOG DEVELOPMENT LATE
TONIGHT...PARTICULARLY AT KRFD AND KDPA. HOWEVER...THERE IS
UNCERTAINTY DUE TO THE POSSIBILITY OF CLOUD COVER. THEREFORE...I
HAVE LEFT THE MENTION OUT OF THE TAFS AT THIS TIME.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH WITH SNOW TRENDS.
* MEDIUM WITH CEILING TRENDS.
KJB/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS.
FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY
NORTHEAST WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR.
TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
KJB
&&
.MARINE...
100 AM CST
SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT
WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY
FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE
SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS
AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE
UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER
NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE
LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT
ADVISORY FOR THE ILLINOIS AND INDIANA NEAR SHORES.
HOWEVER...THERE ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR
SHORES DUE TO THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO
BE MONITORED OVER THE NEXT COUPLE DAYS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
510 AM CST WED JAN 20 2016
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CIGS REDEVELOPING BY LATE MORNING AND CONTINUING INTO THE
AFTERNOON.
KJB
//DISCUSSION...UPDATED 12Z...
THE ACCUMULATING SNOW HAS COME TO AN END. HOWEVER...A FEW
LINGERING FLURRIES COULD LINGER FOR THE NEXT FEW HOURS...BUT NO
IMPACTS ARE EXPECTED. OTHERWISE...IT APPEARS THAT A PERIOD OF VFR
CIGS OF 4-6 KFT AGL WILL BE THE RULE FOR THE NEXT FEW
HOURS...BEFORE SOME LOWER MVFR CIGS REDEVELOP OVER THE AREA BY
LATE MORNING. THESE LOWER CIGS COULD HANG ACROSS MUCH OF THE AREA
THROUGH THE DAY.
THERE IS A SMALL CHANCE OF SOME FOG DEVELOPMENT LATE
TONIGHT...PARTICULARLY AT KRFD AND KDPA. HOWEVER...THERE IS
UNCERTAINTY DUE TO THE POSSIBILITY OF CLOUD COVER. THEREFORE...I
HAVE LEFT THE MENTION OUT OF THE TAFS AT THIS TIME.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
HIGH FOR ALL ELEMENTS.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS.
FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY
NORTHEAST WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR.
TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
KJB
&&
.MARINE...
100 AM CST
SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT
WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY
FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE
SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS
AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE
UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER
NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE
LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT
ADVISORY FOR THE ILLINOIS AND INDIANA NEAR SHORES.
HOWEVER...THERE ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR
SHORES DUE TO THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO
BE MONITORED OVER THE NEXT COUPLE DAYS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS GOODLAND KS
308 AM MST WED JAN 20 2016
.UPDATE...
ISSUED AT 307 AM MST WED JAN 20 2016
LATEST OBSERVATIONS/TRENDS INDICATE THE FREEZING FOG WILL BE EAST
OF THE COLORADO BORDER. HAVE SHIFTED THE COVERAGE OF FOG IN THE
FORECAST FURTHER EAST AS A RESULT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 237 AM MST WED JAN 20 2016
LATEST SATELLITE IMAGERY AND UPPER AIR ANALYSIS SHOWS SEMI ZONAL
FLOW OVER THE CONUS. A LONG BAND OF CLOUD COVER WAS EVIDENT OVER
THE ROCKIES AHEAD OF A SHORT WAVE TROUGH. LOW CLOUDS AND FOG WERE
MOVING NORTH OVER THE TRI-STATE AREA DUE TO INCREASED MOISTURE
ADVECTION FROM THE LOW LEVEL JET. LATEST OBSERVATIONS SHOW
VISIBILITIES UNDER A MILE BEING REPORTED SPORADICALLY UNDER THE LOW
CLOUDS.
TODAY EXPECT THE FOG AND LOW CLOUDS TO PROGRESS NORTHWARD ACROSS THE
ENTIRE AREA. THE WORST OF THE FOG WILL BE EAST OF THE COLORADO
BORDER...WITH THE LOWEST VISIBILITIES OCCURRING DURING THE FIRST
HALF OF THE MORNING. DUE TO CLOUDS REMAINING OVER THE AREA THROUGH
THE DAY...THE FOG MAY LINGER A BIT LONGER THAN NORMAL. LOCATIONS
WHERE VISIBILITIES ARE UNDER A MILE WILL LIKELY HAVE A THIN GLAZE OF
ICE DEVELOP ON EXPOSED SURFACES.
OTHERWISE AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE ACROSS THE AREA
TODAY. DUE TO THE WEAK LIFT AND MOST OF THE MOISTURE REMAINING
ABOVE 700MB...DO NOT ANTICIPATE ANY PRECIPITATION OCCURRING DURING
THE DAY.
TONIGHT A SECOND UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE
AREA...CLOSING OFF FROM THE REST OF THE UPPER LEVEL FLOW OVER THE
NORTHEAST HALF OF THE AREA. THE MAJORITY OF THE VORTICITY WILL BE
WITH THE FIRST SHORT WAVE TROUGH...AHEAD OF THIS SECOND ONE. THIS
WILL LEAD TO LITTLE OR NO MID/UPPER LEVEL LIFT WITH THIS TROUGH AS
IT MOVES THROUGH. HOWEVER WEAK LOW LEVEL FRONTOGENESIS...IN THE
FIRST KILOMETER ABOVE GROUND WHERE THE ENVIRONMENT WILL BE
SATURATED...WILL LEAD TO SOME SNOW DEVELOPING AFTER MIDNIGHT OVER
THE NORTHEAST QUADRANT OF THE AREA. THIS AREA OF SNOWFALL WILL
GRADUALLY MOVE EAST WITH THE PARENT TROUGH.
MEANWHILE ANOTHER AREA OF LIFT/LOW LEVEL FRONTOGENESIS WILL DEVELOP
OVER THE NORTHWEST QUADRANT OF THE AREA BEHIND THE CLOSED LOW. THE
FRONTOGENESIS IN THIS PART OF THE AREA IS STRONGER THAN TO THE EAST
AND THE WEAK LIFT WITH IT IS DEEPER. IN ADDITION THE HIGH-RESOLUTION
MODELS ARE INDICATING A BETTER SHOT OF SNOW DEVELOPING THERE THAN
OVER THE EAST. WITH THIS IN MIND WILL HAVE THE BETTER CHANCES FOR
SNOWFALL OVER THE NORTHWEST PART OF THE AREA.
A COLD FRONT WILL ALSO MOVE THROUGH THE AREA WITH THE SECOND UPPER
LEVEL TROUGH AND AHEAD OF THE SNOWFALL. BEHIND THE FRONT WINDS WILL
INCREASE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 237 AM MST WED JAN 20 2016
THURSDAY MORNING THE LIGHT SNOW WILL CONTINUE OVER BOTH THE
NORTHEAST AND NORTHWEST QUADRANTS OF THE AREA...GRADUALLY MOVING
EAST THROUGH THE MORNING. BY THE EARLY AFTERNOON THE WEAK LIFT WILL
END CAUSING ANY LINGERING SNOW TO END AS WELL. TOTAL SNOWFALL FOR
TONIGHT AND THURSDAY WILL BE LESS THAN AN INCH.
IN ADDITION TO THE SNOW NORTH WINDS WILL BE WINDY...WITH GUSTS UP TO
40 MPH OVER THE WEST HALF OF THE AREA. TO THE EAST THE WINDS WILL
NOT BE AS STRONG DUE TO A WEAKER LOW LEVEL JET OVERHEAD. THE WINDS
WILL LEAD TO BLOWING SNOW WHICH MAY REDUCE VISIBILITIES SOME.
THE BLOWING SNOW WILL END DURING THE AFTERNOON. BEHIND THE SNOW
CLOUDS WILL BEGIN TO CLEAR AS DRIER AIR MOVES INTO THE AREA FROM THE
WEST.
THURSDAY NIGHT WINDS WILL QUICKLY DECLINE DURING THE EVENING.
MEANWHILE CLOUDS WILL CONTINUE TO CLEAR FROM WEST TO EAST. WITH A
COOLER AIR MASS IN PLACE TEMPERATURES WILL FALL INTO THE TEENS.
THIS WILL LEAD TO WIND CHILLS IN THE SINGLE DIGITS BY SUNRISE.
FRIDAY/FRIDAY NIGHT WILL BE UNEVENTFUL AS DRIER AIR REMAINS IN PLACE
AS A LONG WAVE RIDGE MOVES OVERHEAD. TEMPERATURES WILL WARM TO NEAR
NORMAL.
SATURDAY...UPPER RIDGE AXIS MOVES OVER THE AREA DURING THE DAY
AHEAD OF A BROAD UPPER TROUGH WHOSE AXIS MOVES ASHORE BY SUNSET.
FLOW ALOFT SHIFTS TO THE SOUTHWEST AS A RESULT AND CONTINUES THROUGH
THE NIGHT. SOME HIGH CLOUDINESS EXPECTED DURING THE DAY...DECREASING
SOME OVERNIGHT. NO PRECIPITATION EXPECTED. AFTERNOON
TEMPERATURES PEAK IN THE MID 40S TO MID 50S (EAST TO WEST) WITH
OVERNIGHT LOWS IN THE LOW TO MID 20S.
SUNDAY...LONG RANGE MODELS IN BETTER AGREEMENT (COMPARED TO 24 HOURS
AGO) BRINGING BASE OF UPPER TROUGH INTO THE AREA BY DAYS END THEN
INTO THE MIDWEST OVERNIGHT. COLD FRONT MOVES THROUGH AS WELL WITH
NORTHERLY SURFACE WINDS. MODELS DISAGREE ON EXTENT OF COLD AIR WITH
THE ECMWF SEVERAL DEGREES COLDER AT 850MB WHEN COMPARED TO THE GFS.
CURRENT FORECAST HIGHS IN THE MID TO UPPER 40S WOULD FAVOR THE GFS
SOLUTION. NORTH WINDS CONTINUE OVERNIGHT WITH LOW TEMPERATURES IN
THE LOW TO MID 20S. AS FAR AS PRECIPITATION CHANCES...WILL KEEP SOME
SLIGHT CHANCE POPS GOING FOR THE DAY...INCREASING JUST A BIT
OVERNIGHT.
MONDAY...SUNDAYS WEATHER SYSTEM MOVES AWAY FROM THE AREA BUT THE
FORECAST AREA IS CAUGHT IN NORTHWEST FLOW ALOFT ALLOWING MORE
WEATHER SYSTEMS TO MOVE INTO THE AREA. CURRENTLY HAVE A DRY FORECAST
BUT WOULDNT BE SURPRISED IF WE HAVE SOME SPOTTY LIGHT PRECIP. MAY
SEE BREEZY NORTHWEST WINDS DURING THE DAY AS WELL. AFTERNOON
TEMPERATURES A BIT COOLER AND JUST BELOW NORMAL WITH UPPER 30S TO
LOW 40S. LOOKING AT SOME DECREASING CLOUDINESS OVERNIGHT WITH LOW
TEMPERATURES IN THE MID TEENS TO LOW 20S.
TUESDAY...SUNSHINE RETURNS TO THE AREA AS HIGH AMPLITUDE RIDGE AXIS
MOVES SLOWLY TOWARD THE AREA DURING THE DAY. RIDGE AXIS BREAKS DOWN
PRETTY QUICKLY OVERNIGHT WITH SOME INCREASE IN HIGH CLOUDS EXPECTED.
AFTERNOON TEMPERATURES WARM BACK INTO THE LOW TO MID 40S WITH
OVERNIGHT LOWS AGAIN IN THE MID TEENS TO LOW 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1023 PM MST TUE JAN 19 2016
VFR CONDITIONS WILL CONTINUE BRIEFLY AT KGLD AND KMCK AND THEN
DETERIORATE TO MVFR AND LOWER, ESPECIALLY AT KMCK. THE HRRR KEEPS
KGLD AT VFR WHILE THE NAM BRINGS SOME LOWER CONDITIONS. CONDITIONS
SHOULD IMPROVE RATHER EARLY WEDNESDAY MORNING EVEN AT KMCK. SOME
MID LEVEL CLOUDS REMAIN IN RESPONSE TO THE NEXT SHORTWAVE THAT
COMES THROUGH WEDNESDAY AFTERNOON. CLOUDS DECREASE BRIEFLY
WEDNESDAY EVENING IN A BRIEF LULL BEFORE THE NEXT SHORTWAVE
AFFECTS THE AREA.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...JTL
LONG TERM...99/JTL
AVIATION...FS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1041 AM EST WED JAN 20 2016
.SYNOPSIS...
A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS
AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY
INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE
REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING
MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT
SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL
SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY
EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE
FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS.
P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT
RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN
RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD
OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND
COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL
MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT
BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES
THIS AFTN BEFORE THICKER CLDNS ARRIVES.
ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD
BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW
TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS
FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH.
HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE
IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE
SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY
EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S.
WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE
LEANED TOWARD THE COOLER MET NUMBERS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE
FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND
DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL
UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW
AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO
BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE
SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF
THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT
BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL
TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH
CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION
OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES.
FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A
TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A
SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY
MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS
THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION
FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND
WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND
EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF
THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE
NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF
THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH
RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN.
FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF
LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF
THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD
FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN
SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE
POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES
OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN
RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT
OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH
FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR
NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN
PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND
LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN.
AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS
CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND
THERMODYNAMIC PROFILES CHANGE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES
SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE
WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A
GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE
CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE
CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW
FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN
SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND
MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH
DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE
MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S
BY MON.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID AFTN TODAY.
BUT...CLOUDS WILL INCREASE AND LWR QUICKLY...AS AN UPR LEVEL
SYSTEM MOVES TOWARDS THE REGION. THAT UPR LEVEL SYSTEM WILL THEN
CROSS THE REGION LATE THIS AFTN INTO EARLY TNGT...BRINGING A CHC
FOR SOME LIGHT SNOW. MAINLY VFR CIGS ARE STILL EXPECTED AS THE
LIGHT SNOW MOVES THRU. HOWEVER...MVFR CIGS WILL BE POSSIBLE...ESPLY
AT RIC/SBY/PHF. NW WINDS EARLY TODAY...WILL SHIFT TO THE W THEN SW
LATE THIS MORNG INTO EARLY TNGT...THEN BACK AGAIN TO THE NW OVRNGT
TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES WILL PASS OVER THE
AREA ON THU. A STRONG WINTER STORM WILL THEN AFFECT THE REGION
LATE THU NGT INTO THE WEEKEND.
&&
.MARINE...
SCA CONDITIONS WILL CONTINUE UNTIL 10 AM THIS MORNG OVR ALL WTRS
EXCEPT THE RIVERS...DUE TO RATHER STRONG NW WINDS STILL OCCURRING
AS HI PRES BLDS JUST TO THE W OF THE WTRS. THE HI WILL BLD RIGHT
OVR THE WTRS EARLY THIS AFTN...THEN WEAKEN AS AN UPR LEVEL SYSTEM
SLIDES ACRS THE AREA AND OFF THE CST LATE THIS AFTN INTO EARLY
TNGT. WINDS WILL BECOME WSW THIS AFTN THRU EARLY TNGT...THEN BECOME
NW AGAIN LATE TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES BLDS
INTO AND OVR THE AREA DURING THU.
ATTENTION THEN TURNS TO A POTENT STORM SYSTEM SET TO IMPACT THE
REGION FRI INTO SUN. INCREASINGLY POOR BOATING CONDITIONS ANTICIPATED
BY LATER FRI THRU THE WEEKEND. NNW WINDS VEER AROUND TO THE NNE
EARLY FRI...THEN INCREASE FRI AFTN/EVENG...AS LO PRES LIFTS ALONG
THE SE CST AND HI PRES BLDS INTO CANADA. THE SFC LOW LIFTS OFF THE
MID-ATLC CST FRI NIGHT INTO SAT...LIFTING AWAY FM THE CST SAT THRU
SUN. STRONG SCA WINDS EXPECTED LATER FRI INTO SUN...WITH GALE
FORCE WINDS POSSIBLE OVR THE CSTL WTRS AND CHES BAY LATE FRI NGT
INTO SUN...AS FLO TURNS FM NE TO NNW. SEAS WILL ALSO BLD QUICKLY
REACHING AS HIGH AS 8-12+ FT SAT.
&&
.TIDES/COASTAL FLOODING...
ISSUED LOW WATER ADVISORY FOR ALL MARINE ZNS EXCEPT THE
RIVERS...CURRITUCK SND...AND NC CSTL WTRS FM 9 AM THIS MORNG UNTIL
2 PM...DUE TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN
LOWER LOW WATER.
TIDAL ANOMALIES ARE FORECAST TO REACH 1.5 TO 2.0 FEET LATE FRI
INTO SAT...AS LO PRES IMPACTS THE REGION. COMBINATION OF STRONG
ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES REACHING
MHHW WILL PUSH CSTL AREAS OF THE ERN SHORE TOWARD MINOR FLOODING
THRESHOLDS. STRONG NW WINDS BEHIND THE DEPARTING SYSTEM WILL
POTENTIALLY FAVOR MINOR FLOODING OF THE CHESAPEAKE BAY SIDE OF THE
LOWER EASTERN SHORE.
WITH GALE CONDITIONS POSSIBLE LATE FRI NGT INTO SAT AND SEAS
BUILDING TO 5 TO 12 FT...BEACH EROSION AND GENERAL SHORELINE
EROSION IS EXPECTED ESPECIALLY ALONG THE LOWER BAY AND PORTIONS OF
THE CST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...LOW WATER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
ANZ630>632-634-650-652-654-656.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...ALB/ESS
SHORT TERM...ESS
LONG TERM...MAS
AVIATION...TMG
MARINE...TMG
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1102 AM EST WED JAN 20 2016
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 315 AM EST WED JAN 20 2016
AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY.
TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL
MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT
CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS
WEEKEND OR EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1102 AM EST WED JAN 20 2016
I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW.
THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING
REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E
DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW
AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE
STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E
DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION.
REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE
ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES
EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES
WITH FLURRIES.
UPDATE ISSUED AT 551 AM EST WED JAN 20 2016
CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY
GIVEN CURRENT TRENDS:
A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS
SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF
SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6
HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN
TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST
WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE
CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND
GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT
THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE
CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE
EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR
LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD
EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO
WHITEHALL.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES
ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN
INCH OF SNOW.
THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG
COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME
ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND
INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER
TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS
PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN
EFFECT UNTIL 18Z THIS AFTN.
TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW
LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI
TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH
THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A
CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT
IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN
NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS
COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF
SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK.
THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S.
UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST
TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL
AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE
GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT
LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST
NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN
TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE
FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN
INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO
MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN
A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT
THIS EARLY STAGE.
THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING
THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW.
RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF
THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A
CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS
SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE.
FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING
INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE
REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY
TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING
RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR
TRENDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1156 PM EST TUE JAN 19 2016
SNOW WILL BE ON THE INCREASE OVERNIGHT WITH WIDESPREAD IFR
CONDITIONS DEVELOPING BY 12Z WEDNESDAY. EXPECT IFR AND SOME AREAS
OF LIFR WEDNESDAY MORNING WITH CONDITIONS SLOWLY IMPROVING TO
MVFR DURING THE AFTERNOON. WINDS WILL WEST SOUTHWEST AOB 10
KNOTS.
&&
.MARINE...
ISSUED AT 315 AM EST WED JAN 20 2016
WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND
FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF
THE NEARSHORE WATERS.
&&
.HYDROLOGY...
ISSUED AT 324 PM EST TUE JAN 19 2016
WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING...
HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER
AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY
IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO
WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE
REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ050-
056-064.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...HOVING
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
603 AM EST WED JAN 20 2016
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 315 AM EST WED JAN 20 2016
AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY.
TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL
MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT
CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS
WEEKEND OR EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 551 AM EST WED JAN 20 2016
CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY
GIVEN CURRENT TRENDS:
A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS
SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF
SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6
HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN
TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST
WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE
CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND
GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT
THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE
CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE
EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR
LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD
EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO
WHITEHALL.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES
ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN
INCH OF SNOW.
THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG
COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME
ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND
INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER
TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS
PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN
EFFECT UNTIL 18Z THIS AFTN.
TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW
LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI
TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH
THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A
CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT
IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN
NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS
COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF
SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK.
THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S.
UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST
TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL
AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE
GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT
LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST
NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN
TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE
FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN
INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO
MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN
A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT
THIS EARLY STAGE.
THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING
THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW.
RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF
THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A
CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS
SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE.
FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING
INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE
REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY
TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING
RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR
TRENDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1156 PM EST TUE JAN 19 2016
SNOW WILL BE ON THE INCREASE OVERNIGHT WITH WIDESPREAD IFR
CONDITIONS DEVELOPING BY 12Z WEDNESDAY. EXPECT IFR AND SOME AREAS
OF LIFR WEDNESDAY MORNING WITH CONDITIONS SLOWLY IMPROVING TO
MVFR DURING THE AFTERNOON. WINDS WILL WEST SOUTHWEST AOB 10
KNOTS.
&&
.MARINE...
ISSUED AT 315 AM EST WED JAN 20 2016
WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND
FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF
THE NEARSHORE WATERS.
&&
.HYDROLOGY...
ISSUED AT 324 PM EST TUE JAN 19 2016
WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING...
HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER
AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY
IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO
WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE
REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ050-
056-064.
LM...NONE.
&&
$$
UPDATE...HOVING
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...HOVING
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1046 AM EST WED JAN 20 2016
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE WILL CROSS THE CAROLINAS
TODAY. ANOTHER LOW IS EXPECTED TO DEVELOP TO OUR WEST ON THURSDAY
AND SPREAD PRECIPITATION ACROSS THE AREA THURSDAY NIGHT AND FRIDAY
AS IT MOVES ACROSS THE REGION. THE SYSTEM WILL EVENTUALLY MOVE OFF
THE MID ATLANTIC COAST OVER THE WEEKEND WITH DRIER HIGH PRESSURE
SPREADING BACK OVER THE REGION IN ITS WAKE ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM EST...EVEN VERY LIGHT RETURNS ON RADAR HAVE BEEN
REMARKABLY EFFICIENT AT PRODUCING A SLIPPERY DUSTING OF SNOW DESPITE
THE DRY SUB CLOUD AIR. BOTH THE LATEST RAP AND 12Z NAM ARE NOW
PRESENTING MORE ISENTROPIC UPGLIDE THROUGH A NARROW WINDOW THIS
AFTERNOON...AND WET BULB PROFILES SUPPORT MAINLY SNOW UNTIL MID
LEVELS DRY OUT THIS EVENING. GIVEN THE UPTICK IN QPF AND ASSOCIATED
COLD/SLIPPERY ROADWAYS IMPACT...HAVE EXPANDED THE ADVISORY INTO
STEPHENS COUNTY IN NE GA...THE UPSTATE MOUNTAINS...AND THE NC
FOOTHILLS AND NW PIEDMONT. WILL ALSO UPGRADE GRAHAM COUNTY TO A
WARNING WITH 3 TO 5 INCH SNOW TOTALS QUITE WIDESPREAD AS THE HEAVIER
RATES MOVES IN WITH THE REFLECTIVE BAND TO THE WEST.
THE UPPER SUPPORT WITH THE PASSING WAVE AND THE LOWER LEVEL
ISENTROPIC LIFT SHUT OFF QUICKLY TOWARD EVENING. MOISTURE LINGERS AT
LOW LEVELS...BUT MID LEVELS DRY OUT TO WARRANT A POSSIBLE SWITCHOVER
FROM WEST TO EAST OF LIGHT FREEZING RAIN OR FREEZING DRIZZLE. BLACK
ICE CONDITIONS WILL REMAIN A PROBLEM OVERNIGHT IN ANY AREAS
RECEIVING ACCUMULATING SNOW GIVEN MINS IN THE 20S AND LOWER 30S.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AS OF 340 AM WEDNESDAY...LATEST IR SATELLITE IMAGES INDICATED THAT
THE SYSTEM THAT WILL IMPACT THE REGION LATE THIS WEEK WAS OVER THE
PACIFIC NORTHWEST. THE FORECAST WILL BE AIDED BY GENERALLY GOOD SHORT
RANGE MODEL AGREEMENT...AND DETAILED TEMPERATURE FIELDS FROM THE
NAM12. I WILL USE A BLEND OF THE SYNOPTIC FEATURES OF THE GFS AND
ECMWF FROM THURSDAY THROUGH SATURDAY. HOWEVER...ON FRIDAY...I WILL
BLEND IN LLVL THERMAL DETAILS FROM THE NAM12...BANKING ON THE BETTER
HANDLING OF COLD AIR DAMMING.
THURSDAY...0Z RUN OF THE GFS AND ECMWF HAVE TRENDED SLOWER WITH THE
ONSET OF WARM FRONT ASSOCIATED PRECIP. THIS FORECAST PACKAGE WILL
FEATURE SLOWER INCREASE OF POPS FRONT SW TO NE...DECREASING QPF. BY
LATE THURSDAY AFTERNOON...I WILL FORECAST LIKELY POPS ACROSS THE
UPPER SAVANNAH RIVER VALLEY TO THE EXTREME WESTERN NC MTNS...SCHC
OVER THE NC PIEDMONT AND FOOTHILLS. HIGH TEMPERATURES WILL GENERALLY
RANGE IN THE MID 40S.
BY 12Z FRIDAY...THE CENTER OF A WELL ORGANIZED LOW PRESSURE SYSTEM
IS FORECAST OVER NRN MS/AL...WITH GFS FASTER NEAR THE TN/AL/GA STATE
INTERSECTION. IT IS IMPORTANT TO NOTE THAT THE SFC HIGH WILL LIKELY
START TO RIDGE SW ACROSS THE MID ATLANTIC STATES AND ALONG THE EAST
FACING SLOPES OF THE SOUTHERN APPALACHIANS. THE PATTERN SUPPORTS
DEEP ISENTROPIC LIFT ALONG WITH IDEAL UPSLOPE FLOW. THE COMBINATION
OF DEEP MOISTURE AND DEEP LLVL LIFT WILL SUPPORT NEAR 100 PERCENT BY
THE PRE DAWN HOURS FRIDAY. COLD AIR DAMMING WILL SURGE ACROSS THE
FOOTHILLS AND PIEDMONT...SUPPORTED BY GUSTY NE WINDS. FREEZING
TEMPERATURES ARE EXPECTED TO SPREAD SW ACROSS THE EAST FACING
SLOPES...UPPER FRENCH BROAD VALLEY...AND EAST ACROSS THE I-40
CORRIDOR. GENERALLY...H85 WAA WILL SUPPORT RAINFALL THURSDAY
EVENING. HOWEVER...THE HEART OF THE CAD WILL ERODE THE WARM NOSE AND
SHOULD YIELD AN IMPRESSIVE ROUND OF SLEET ACROSS THE NC FOOTHILLS
DURING THE LATE NIGHT HOURS THURSDAY NIGHT. SURGING COLD AIR SHOULD
PROVIDE COLD THERMAL PROFILES...SUPPORTING A PERIOD OF FOOTHILL SNOW
DURING THE PRE DAWN HOURS FRI.
AFTER SUNRISE FRIDAY...THE LOW CENTER IS FORECAST TO LIFT NE ACROSS
NRN GA...PROVIDING A DEEPER WARM NOSE ACROSS THE WESTERN CAROLINAS
AND NE GA. HOWEVER...THE BL ACROSS THE NC ZONES WILL MAINTAIN
REINFORCING CAA. A CLASSIC FREEZING RAIN PROFILE DEVELOPS NORTH THE
NC/SC LINE DURING THE EARLY DAYLIGHT HOURS. THE FREEZING RAIN LINE
WILL LIFT NORTH ACROSS THE NRN FOOTHILLS AND NRN NC MTNS BY MID DAY.
THE PEAK H5 Q-VECTOR CONVERGENCE WILL CROSS OVER THE FORECAST AREA
ON FRI...PEAKING AROUND 18Z. THE ADDED FORCING SHOULD RESULT IN A
PERIOD OF MODERATE FZRA ACROSS THE I-40 CORRIDOR FRIDAY AFTERNOON.
BY 0Z SAT...DAMAGING FREEZING RAIN IS EXPECTED ACROSS THE UNIFOUR
EAST ACROSS THE UPPER I-77 CORRIDOR...NORTH OF LAKE NORMAN.
FRIDAY NIGHT...THE LOW CENTER WILL REACH THE OUTER BANKS OF NC AS
THE CENTER OF A CLOSED H5 LOW TRACKS OVER THE SOUTHERN APPALACHIANS.
GRADUALLY...H85 WINDS WILL INCREASE FROM THE NW...RESULTING IN CAA
ACROSS THE REGION. A WINTRY MIX AND RAIN WILL TRANSITION TO SNOW
FROM WEST TO EAST FRIDAY NIGHT. ACCUMULATING SNOWFALL SHOULD INCREASE
FRIDAY EVENING...THEN REMAINING STEADY OVER THE TN BORDER COUNTIES
THROUGH SAT. STORM TOTAL SNOWFALL IS FORECAST TO RANGE FROM NEARLY A
FOOT OVER THE HIGHEST ELEVATIONS OF AVERY COUNTY...TO 5 TO 8 INCHES
ACROSS THE BLUE RIDGE...WITH SEVERAL INCHES ACROSS THE I-40
CORRIDOR.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 410 AM WEDNESDAY...SUNDAY AND MONDAY...N-S SFC HIGH PRESSURE
WILL SLIDE EAST ACROSS THE REGION UNDER THE AXIS OF A PASSING H5 L/W
RIDGE. CONDITIONS WILL REMAIN DRY WITH TEMPS RETURNING TO SEASONABLE
VALUES. A COLD FRONT IS FORECAST TO PASS OVER THE MTNS MON
NIGHT...PASSING SLOWLY EAST ON TUESDAY. THERMAL PROFILES WILL RESULT
IN LIGHT RAIN TO SWITCH TO SNOW ACROSS THE MTNS AND NC FOOTHILLS
EARLY TUESDAY MORNING. SHORTLY AFTER SUNRISE TUESDAY...PRECIP WILL
FALL AS RAIN ACROSS THE REGION. HIGH TEMPERATURE ON TUESDAY IS
FORECAST TO RANGE IN THE 40S ACROSS THE MTNS TO LOW TO MID 50S EAST.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT AND ELSEWHERE...LOWERING VFR CIGS WILL CONTINUE THROUGH THE
AFTERNOON...WITH MVFR LIKELY UNDER ANY BETTER SNOW SHOWERS..STARTING
AT KAVL FIRST. EXPECT THE SNOW POTENTIAL WINDOW TO START UP
MOMENTARILY AT KAVL AND THEN SPREAD EAST THROUGH THE AFTN...REACHING
KCLT MAINLY 20Z TO 00Z. THE WESTERLY FLOW ABOVE THE SFC IS NOT AS
FAVORABLE FOR PRECIP ACROSS UPSTATE SC...SO A VCSH REMAINS MORE
APPROPRIATE FOR KGSP/KGMU/KAND. CONDITIONS WILL IMPROVE AFTER 23Z.
WIND SHOULD COME AROUND TO SW THIS EVENING...AND EVENTUALLY NW OR N
AND LIGHT OVERNIGHT.
OUTLOOK...THURSDAY MIGHT BE A BRIEF BREAK IN THE ACTION. A STRONGER
STORM SYSTEM WILL ARRIVE FROM THE WEST THURSDAY NIGHT AND FRIDAY...
WITH WIDESPREAD RESTRICTIONS AND WINTRY PRECIPITATION POSSIBLE...
ESPECIALLY FROM KAVL TO KHKY. THE SYSTEM COULD LINGER INTO
SATURDAY...WITH WINTRY PTYPES POSSIBLY PERSISTING AS WELL.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-12Z
KCLT HIGH 100% HIGH 98% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 96% HIGH 100% HIGH 100%
KAVL HIGH 98% MED 70% MED 64% MED 74%
KHKY HIGH 100% MED 73% HIGH 96% HIGH 100%
KGMU HIGH 100% HIGH 93% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 88% HIGH 94% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLET HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK:
WWW.WEATHER.GOV/GSP/AVIATION
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR GAZ010-017-
018.
NC...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR NCZ033-
035>037-048>053-056-057-059-062>065-068-069-501>510.
WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NCZ058.
SC...WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR SCZ001>003.
&&
$$
SYNOPSIS...DEO
NEAR TERM...HG/PM
SHORT TERM...NED
LONG TERM...NED
AVIATION...HG/PM
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1045 AM MST WED JAN 20 2016
.UPDATE...
ISSUED AT 929 AM MST WED JAN 20 2016
12Z NAM AND LATEST HRRR HAVE COME IN WITH HEAVIER SNOW OVER THE
CENTRAL MOUNTAINS TODAY AND TONIGHT...WITH UP TO 8 INCHES OVER
HIGHER WEST FACING SLOPES OF THE SAWATCH RANGE AND A FEW POCKETS
OF 6 OVER THE NORTHERN LA GARITAS. WILL THUS HOIST A WINTER
WEATHER ADVISORY FOR THESE AREAS FOR TODAY INTO THIS EVENING.
OUTSIDE OF THE ADVISORY AREAS...HAVE BOOSTED POPS AND SNOW AMOUNTS
SLIGHTLY AROUND LEADVILLE...WHILE KEEPING FORECAST FOR AREAS
FARTHER EAST UNCHANGED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM MST WED JAN 20 2016
ONE DISTURBANCE WILL BE MOVING ACRS THE AREA THIS MORNING...WITH
ANOTHER ONE ENTERING WRN CO AROUND MIDDAY AND MOVING ACRS THE AREA
THROUGH TONIGHT.
THE FIRST DISTURBANCE WL BRING SOME SNOW TO THE CONTDVD THIS
MORNING...WITH A LULL IN ACTIVITY BY LATE MORNING AND EARLY
AFTERNOON. THEN AS THE NEXT DISTURBANCE APPROACHES THIS AFTERNOON
AND THEN MOVES ACRS THE AREA TONIGHT...THE SNOW WL INCREASE AGAIN
ALONG THE CONTDVD. SOME OF THE ERN MTNS COULD SEE SOME LIGHT SNOW
THIS MORNING ASSOCIATED WITH THIS FIRST DISTURBANCE...BUT THE SERN
PLAINS IS EXPECTED TO BE DRY.
TONIGHT...AS THE NEXT DISTURBANCE MOVES ACRS THE AREA...THERE WL
PROBABLY BE THE CHANCE FOR SOME LIGHT SNOW ACRS THE SAN LUIS VALLEY
FOR A FEW HOURS...AND ACRS THE ERN MTNS. THE CHANCE FOR PCPN WL
THEN SPREAD TO THE SERN PLAINS. OVERNIGHT...PCPN CHANCES ARE
EXPECTED TO DECREASE OR END FROM NW TO SE ACRS THE FORECAST AREA AS
THE DISTURBANCE MOVES SOUTHEASTWARD ACRS THE AREA. HOWEVER...
FAVORABLE NWRLY FLOW WL PROBABLY KEEP SOME LIGHT SNOW GOING OVR THE
CENTRAL MTNS.
MOST OF THE MTNS AREA TONIGHT WL JUST SEE SOME LIGHT
ACCUMULATIONS...HOWEVER THE CENTRAL MTNS WL PROBABLY SEE UP TO SIX
INCHES OF ACCUMULATION...WITH THE HIGHEST AMOUNTS MAINLY BEING NORTH
OF COTTONWOOD PASS.
WITH THE FRONT EXPECTED TO HOLD OFF MOVING INTO THE SERN PLAINS
UNTIL THIS EVENING...THE WESTERLY FLOW AND MIXING TODAY SHOULD WARM
TEMPS INTO THE UPPER 40S TO LOWER 50S ACRS THE SERN PLAINS WHICH IS
ABOVE AVERAGE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 425 AM MST WED JAN 20 2016
NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM
WITH PRIMARY METEOROLOGICAL CONCERNS BEING TEMPERATURES...POPS AND
GUSTY WINDS AT TIMES.
INITIAL DISTURBANCE IS EXPECTED TO BE DEPARTING THE FORECAST
DISTRICT THURSDAY...ALLOWING FOR ISOLATED SHOWER POTENTIAL OVER
EASTERN SECTIONS AND THE CENTRAL MOUNTAINS...PRIMARILY DURING THE
MORNING HOURS. IN ADDITION...GUSTY WINDS ARE ANTICIPATED OVER
SEVERAL LOCATIONS FROM THURSDAY INTO THURSDAY NIGHT AS THE SYSTEM
PULLS EAST OF THE CWA.
A DRY UPPER RIDGING TO ZONAL/SOUTHWESTERLY UPPER PATTERN IS STILL
EXPECTED TO DEVELOP OVER THE FORECAST DISTRICT FROM THURSDAY NIGHT
INTO SATURDAY...ALLOWING FOR GENERALLY DRY AND WARMER CONDITIONS
IN COMBINATION WITH GUSTY WINDS AT TIMES.
NEXT UPPER DISTURBANCE IN COMBINATION WITH NORTH TO NORTHEASTERLY
SURFACE SURGES ARE STILL EXPECTED TO IMPACT THE FORECAST DISTRICT
FROM LATER THIS WEEKEND INTO EARLY NEXT WEEK ALLOWING FOR A RETURN
OF COOLER CONDITIONS AND INCREASED PRECIPITATION CHANCES. AT THIS
TIME...IT APPEARS THAT LOCATIONS SUCH AS THE I-25 CORRIDOR AND
PORTIONS OF THE EASTERN PLAINS WILL HAVE THE HIGHEST POTENTIAL OF
RECEIVING MEASURABLE PRECIPITATION DURING THE LATER MONDAY INTO
TUESDAY TIME-FRAME.
WARMEST TEMPERATURES DURING THE LONGER TERM SHOULD BE NOTED
SATURDAY...WITH COOLEST READINGS EXPECTED THURSDAY AND THEN AGAIN
BY NEXT MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1037 AM MST WED JAN 20 2016
AT KALS...WEB CAMS SUGGEST BRIEF PERIOD OF FOG BEGINNING TO
DISSIPATE ALREADY...AND WILL KEEP ONLY TEMPO IFR CONDITIONS 18Z-
19Z BEFORE CIGS/VIS BECOME VFR AGAIN. FOR THE AFTERNOON AND
TONIGHT...PREVAILING CONDITIONS WILL BE VFR...BUT WILL CARRY A
VCSH MENTION INTO THE EVENING AS A FEW -SHSN MOVE OFF THE HIGHER
TERRAIN AND ACROSS THE VALLEY.
AT KCOS AND KPUB...VFR CONDITIONS TODAY AND TONIGHT...BUT WILL
CARRY A VCSH MENTION INTO THE EVENING AS A FEW -SHSN DEVELOP AS
UPPER TROUGH MOVES OVER THE REGION.
MOUNTAINS...ESPECIALLY ALONG THE CONTINENTAL DIVIDE...WILL SEE A
PERIOD OF IFR/LIFR CIGS/VIS IN SNOW DEVELOP THIS AFTERNOON AND
CONTINUE THROUGH THE EVENING. SOME SLOW CLEARING THEN AFTER 06Z-
08Z...ESPECIALLY FROM KMYP SOUTHWARD.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ058-
060-066.
&&
$$
UPDATE...PETERSEN
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
936 AM MST WED JAN 20 2016
.UPDATE...
ISSUED AT 929 AM MST WED JAN 20 2016
12Z NAM AND LATEST HRRR HAVE COME IN WITH HEAVIER SNOW OVER THE
CENTRAL MOUNTAINS TODAY AND TONIGHT...WITH UP TO 8 INCHES OVER
HIGHER WEST FACING SLOPES OF THE SAWATCH RANGE AND A FEW POCKETS
OF 6 OVER THE NORTHERN LA GARITAS. WILL THUS HOIST A WINTER
WEATHER ADVISORY FOR THESE AREAS FOR TODAY INTO THIS EVENING.
OUTSIDE OF THE ADVISORY AREAS...HAVE BOOSTED POPS AND SNOW AMOUNTS
SLIGHTLY AROUND LEADVILLE...WHILE KEEPING FORECAST FOR AREAS
FARTHER EAST UNCHANGED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 425 AM MST WED JAN 20 2016
ONE DISTURBANCE WILL BE MOVING ACRS THE AREA THIS MORNING...WITH
ANOTHER ONE ENTERING WRN CO AROUND MIDDAY AND MOVING ACRS THE AREA
THROUGH TONIGHT.
THE FIRST DISTURBANCE WL BRING SOME SNOW TO THE CONTDVD THIS
MORNING...WITH A LULL IN ACTIVITY BY LATE MORNING AND EARLY
AFTERNOON. THEN AS THE NEXT DISTURBANCE APPROACHES THIS AFTERNOON
AND THEN MOVES ACRS THE AREA TONIGHT...THE SNOW WL INCREASE AGAIN
ALONG THE CONTDVD. SOME OF THE ERN MTNS COULD SEE SOME LIGHT SNOW
THIS MORNING ASSOCIATED WITH THIS FIRST DISTURBANCE...BUT THE SERN
PLAINS IS EXPECTED TO BE DRY.
TONIGHT...AS THE NEXT DISTURBANCE MOVES ACRS THE AREA...THERE WL
PROBABLY BE THE CHANCE FOR SOME LIGHT SNOW ACRS THE SAN LUIS VALLEY
FOR A FEW HOURS...AND ACRS THE ERN MTNS. THE CHANCE FOR PCPN WL
THEN SPREAD TO THE SERN PLAINS. OVERNIGHT...PCPN CHANCES ARE
EXPECTED TO DECREASE OR END FROM NW TO SE ACRS THE FORECAST AREA AS
THE DISTURBANCE MOVES SOUTHEASTWARD ACRS THE AREA. HOWEVER...
FAVORABLE NWRLY FLOW WL PROBABLY KEEP SOME LIGHT SNOW GOING OVR THE
CENTRAL MTNS.
MOST OF THE MTNS AREA TONIGHT WL JUST SEE SOME LIGHT
ACCUMULATIONS...HOWEVER THE CENTRAL MTNS WL PROBABLY SEE UP TO SIX
INCHES OF ACCUMULATION...WITH THE HIGHEST AMOUNTS MAINLY BEING NORTH
OF COTTONWOOD PASS.
WITH THE FRONT EXPECTED TO HOLD OFF MOVING INTO THE SERN PLAINS
UNTIL THIS EVENING...THE WESTERLY FLOW AND MIXING TODAY SHOULD WARM
TEMPS INTO THE UPPER 40S TO LOWER 50S ACRS THE SERN PLAINS WHICH IS
ABOVE AVERAGE.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 425 AM MST WED JAN 20 2016
NOT MANY METEOROLOGICAL ADJUSTMENTS NEEDED DURING THE LONGER TERM
WITH PRIMARY METEOROLOGICAL CONCERNS BEING TEMPERATURES...POPS AND
GUSTY WINDS AT TIMES.
INITIAL DISTURBANCE IS EXPECTED TO BE DEPARTING THE FORECAST
DISTRICT THURSDAY...ALLOWING FOR ISOLATED SHOWER POTENTIAL OVER
EASTERN SECTIONS AND THE CENTRAL MOUNTAINS...PRIMARILY DURING THE
MORNING HOURS. IN ADDITION...GUSTY WINDS ARE ANTICIPATED OVER
SEVERAL LOCATIONS FROM THURSDAY INTO THURSDAY NIGHT AS THE SYSTEM
PULLS EAST OF THE CWA.
A DRY UPPER RIDGING TO ZONAL/SOUTHWESTERLY UPPER PATTERN IS STILL
EXPECTED TO DEVELOP OVER THE FORECAST DISTRICT FROM THURSDAY NIGHT
INTO SATURDAY...ALLOWING FOR GENERALLY DRY AND WARMER CONDITIONS
IN COMBINATION WITH GUSTY WINDS AT TIMES.
NEXT UPPER DISTURBANCE IN COMBINATION WITH NORTH TO NORTHEASTERLY
SURFACE SURGES ARE STILL EXPECTED TO IMPACT THE FORECAST DISTRICT
FROM LATER THIS WEEKEND INTO EARLY NEXT WEEK ALLOWING FOR A RETURN
OF COOLER CONDITIONS AND INCREASED PRECIPITATION CHANCES. AT THIS
TIME...IT APPEARS THAT LOCATIONS SUCH AS THE I-25 CORRIDOR AND
PORTIONS OF THE EASTERN PLAINS WILL HAVE THE HIGHEST POTENTIAL OF
RECEIVING MEASURABLE PRECIPITATION DURING THE LATER MONDAY INTO
TUESDAY TIME-FRAME.
WARMEST TEMPERATURES DURING THE LONGER TERM SHOULD BE NOTED
SATURDAY...WITH COOLEST READINGS EXPECTED THURSDAY AND THEN AGAIN
BY NEXT MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 425 AM MST WED JAN 20 2016
KCOS AND KPUB SHOULD SEE VFR CONDITIONS TODAY WITH THE POTENTIAL FOR
SOME GUSTY WEST TO NW WINDS THIS AFTERNOON. AS A FRONT MOVES THRU
THESE LOCATIONS THIS EVENING...THE WINDS WL BE NW TO N AND GUSTY.
THE COULD BE A FEW SNOW SHOWERS IN THE VCNTY OF THE TERMINALS THIS
EVENING WHICH COULD BRING LOWER CIGS FOR A BRIEF PERIOD.
KALS SHOULD HAVE VFR CONDITIONS THRU THE PERIOD...ALTHOUGH THERE WL
BE THE POTENTIAL FOR SOME SNOW SHOWERS IN THE VCNTY THIS EVENING
WHICH COULD BRING A BRIEF PERIOD OF LOWER CIGS. AS A DISTURBANCE
PASSES THE ARE TONIGHT...WINDS ARE EXPECTED TO BECOME NORTHWESTERLY
AND COULD BE BREEZY FOR A FEW HOURS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ058-
060-066.
&&
$$
UPDATE...PETERSEN
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
547 PM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL
DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST.
THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH
PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
UPDATE...RADAR...SURFACE OBS...AND PUBLIC REPORTS INDICATE AREA
OF LIGHT RAIN AND LIGHT SLEET MIX INTO THE CSRA AND CENTRAL
MIDLANDS. NO ACCUMULATION EXPECTED AS SURFACE TEMPS WILL
REMAIN WELL ABOVE FREEZING. LATEST HIGH RESOLUTION MODELS SUGGEST
THE PRECIPITATION AREA WILL DECREASE IN COVERAGE AS IT MOVES EAST
ACROSS OUR FORECAST AREA (FA) THROUGH EARLY THIS EVENING.
FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS
INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE.
FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND
SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT.
OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40
SOUTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
UPDATED...THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT
IMPACTS INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR
FREEZING RAIN LATE THURSDAY NIGHT THROUGH FRIDAY. WILL POST WINTER
STORM WATCH...
THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER- MID
MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF
THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES
AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN
LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF
MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC
COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES
LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT
THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT
DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z
FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH.
PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER
DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS
THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST
MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE
SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN
INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED
TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL
BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER
GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH
PRECIPITATION.
THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW
OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE
TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER
MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH
FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL
CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO
VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE
OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC
INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO
FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS
FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY
RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE
REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL
PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS
TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE.
COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL
SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A
TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN
SOUTH CAROLINA BY 00Z SATURDAY.
RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND
PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE
NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON
FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS
THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS
THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT
FRIDAY AFTERNOON.
THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID
ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN
ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME
LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS
FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW
LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR
LANCASTER/CHESTERFIELD IF NEEDED.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE
ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT
WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO
THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY
ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS
EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE
LIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A LIGHT RAIN AND SLEET MIXTURE EXPECTED IN THE NEAR TERM. NO SLEET
ACCUMULATION DUE TO TEMPERATURES WELL ABOVE FREEZING. CLOUD BASES
ARE ABOVE VFR LEVEL. PRECIPITATION EXPECTED TO DIMINISH EARLY THIS
EVENING...WITH MID LEVEL CLOUDINESS REMAINING IN PLACE. LIGHT WINDS.
LIGHT RAIN POSSIBLE THURSDAY...BUT CLOUD BASES ARE EXPECTED TO
REMAIN ABOVE VFR LEVEL THRU 18Z.
EXTENDED AVIATION OUTLOOK....PRECIPITATION AND WIDESPREAD IFR TO
MVFR CONDITIONS THURSDAY NIGHT THROUGH SATURDAY.
BREEZY CONDITIONS POSSIBLE SATURDAY/SATURDAY NIGHT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
EVENING FOR SCZ015-016.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
532 PM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL
DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST.
THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH
PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
UPDATE...RADAR AND SURFACE OBS INDICATE AREA OF LIGHT RAIN AND
LIGHT SNOW ACROSS THE UPSTATE SC AND N GA...MOVING EAST. LATEST
HIGH RESOLUTION MODELS SUGGEST THE PRECIPITATION AREA WILL
DECREASE IN COVERAGE AS IT MOVES EAST INTO OUR FORECAST AREA (FA)
LATE THIS AFTERNOON AND EARLY EVENING. HOWEVER...CHANCE OF
PRECIPITATION IN THE VERY NEAR TERM APPEARS VERY HIGH AT LEAST
ACROSS THE NORTHERN FA. LATEST GUIDANCE AND TRENDS SUGGEST THE
NORTHERN FA COULD SEE A MIX OF LIGHT RAIN...LIGHT SNOW...OR SLEET
IN THE NEAR TERM. NO ACCUMULATION EXPECTED AS SURFACE TEMPS WILL
REMAIN WELL ABOVE FREEZING.
FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS
INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE.
FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND
SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT.
OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40
SOUTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
...UPDATED...THREAT FOR WINTRY PRECIPITATION WITH SIGNIFICANT
IMPACTS INCREASING ACROSS THE NORTHERN MIDLANDS MAINLY FOR
FREEZING RAIN LATE THURSDAY NIGHT THROUGH FRIDAY. WILL POST WINTER
STORM WATCH...
THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER- MID
MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF
THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES
AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN
LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF
MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC
COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES
LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT
THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT
DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z
FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH.
PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER
DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS
THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST
MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE
SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN
INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED
TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL
BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER
GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH
PRECIPITATION.
THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW
OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE
TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER
MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH
FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL
CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO
VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE
OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC
INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO
FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS
FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY
RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE
REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL
PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS
TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE.
COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL
SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A
TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN
SOUTH CAROLINA BY 00Z SATURDAY.
RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND
PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE
NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON
FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS
THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS
THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT
FRIDAY AFTERNOON.
THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID
ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN
ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME
LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS
FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW
LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR
LANCASTER/CHESTERFIELD IF NEEDED.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE
ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT
WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO
THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY
ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS
EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE
LIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO
TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON
INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA
OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME
ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE
DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO
MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS
AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER
SUNRISE THURSDAY MORNING.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH
SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WINTER STORM WATCH FROM LATE THURSDAY NIGHT THROUGH SATURDAY
EVENING FOR SCZ015-016.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
406 PM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL
DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST.
THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH
PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
UPDATE...RADAR AND SURFACE OBS INDICATE AREA OF LIGHT RAIN AND
LIGHT SNOW ACROSS THE UPSTATE SC AND N GA...MOVING EAST. LATEST
HIGH RESOLUTION MODELS SUGGEST THE PRECIPITATION AREA WILL
DECREASE IN COVERAGE AS IT MOVES EAST INTO OUR FORECAST AREA (FA)
LATE THIS AFTERNOON AND EARLY EVENING. HOWEVER...CHANCE OF
PRECIPITATION IN THE VERY NEAR TERM APPEARS VERY HIGH AT LEAST
ACROSS THE NORTHERN FA. LATEST GUIDANCE AND TRENDS SUGGEST THE
NORTHERN FA COULD SEE A MIX OF LIGHT RAIN...LIGHT SNOW...OR SLEET
IN THE NEAR TERM. NO ACCUMULATION EXPECTED AS SURFACE TEMPS WILL
REMAIN WELL ABOVE FREEZING.
FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS
INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE.
FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND
SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT.
OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40
SOUTH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER-MID
MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF
THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES
AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN
LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF
MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC
COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES
LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT
THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT
DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z
FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH.
PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER
DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS
THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST
MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE
SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN
INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED
TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL
BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER
GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH
PRECIPITATION.
THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW
OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE
TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER
MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH
FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL
CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO
VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE
OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC
INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO
FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS
FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY
RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE
REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL
PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS
TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE.
COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL
SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A
TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN
SOUTH CAROLINA BY 00Z SATURDAY.
RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND
PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE
NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON
FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS
THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS
THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT
FRIDAY AFTERNOON.
THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID
ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN
ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME
LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS
FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW
LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR
LANCASTER/CHESTERFIELD IF NEEDED.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE
ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT
WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO
THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY
ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS
EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE
LIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO
TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON
INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA
OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME
ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE
DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO
MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS
AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER
SUNRISE THURSDAY MORNING.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH
SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
307 PM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL
DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST.
THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH
PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
REST OF THE AFTERNOON...THE SURFACE RIDGE IS CURRENTLY CENTERED OVER
THE COASTAL PLAIN OF THE CAROLINAS. THE RIDGE WILL HELP LIMIT
MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO
THE FORECAST AREA. THE LATEST HRRR INDICATES PRECIPITATION
DIMINISHING AS IT MOVES INTO THE AREA FROM THE WEST THIS AFTERNOON
INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A
PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION
SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY
PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE
CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20
PERCENT SOUTH LATER THIS AFTERNOON. THE TOP-DOWN METHOD RUN ON BOTH
THE NAM AND GFS NOW INDICATING PATCHES OF LIGHT RAIN ACROSS THE
NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA WITH LOW CHANCE
POPS. GIVEN THE POTENTIAL FOR EVAPORATIVE COOLING WITH THE CURRENT
LOW DEWPOINTS...CANNOT RULE OUT A BRIEF MIX OF SOME SNOW WITH THE
RAIN ACROSS PORTIONS IN THE EXTREME NORTH LATER THIS AFTERNOON...BUT
NO ACCUMULATIONS ARE EXPECTED.
FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS
INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE.
FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND
SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT.
OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40
SOUTH.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
THURSDAY...A STRONG STORM SYSTEM WILL DEVELOP OVER THE LOWER-MID
MISSISSIPPI VALLEY AS AN UPPER TROUGH DEEPENS ACROSS THE MIDDLE OF
THE COUNTRY. A WARM FRONT WILL DEVELOP ALONG THE GULF COAST STATES
AS THE FORMATION OF A SURFACE LOW OCCURS OVER EAST TEXAS/NORTHERN
LOUISIANA AND STRENGTHENING SOUTHERLY 850MB FLOW OFF THE GULF OF
MEXICO INCREASES MOISTURE ACROSS THE FORECAST AREA. ATMOSPHERIC
COLUMN WILL INITIALLY BE QUITE DRY ON THURSDAY WITH PWAT VALUES
LESS THAN A HALF INCH WITH SIGNIFICANT DRY AIR ABOVE 5000FT BUT
THE MOISTURE WILL INCREASE THROUGH THE DAY AS ISENTROPIC LIFT
DEVELOPS NORTH OF THE WARM FRONT AND SATURATES THE COLUMN. BY 00Z
FRIDAY THE PWAT VALUES WILL BE JUST UNDER 1 INCH.
PRECIPITATION ASSOCIATED WITH ISENTROPIC LIFT AND MAYBE A WEAK UPPER
DISTURBANCE IN THE SOUTHWESTERLY FLOW WILL LEAD TO INCREASING POPS
THROUGH THE DAY FROM SOUTHWEST TO NORTHEAST...ALTHOUGH THE LATEST
MODEL RUNS HAVE TRENDED A BIT SLOWER WITH THE ONSET. THERE MAY BE
SOME DIABATIC COOLING EFFECTS FROM PRECIPITATION FALLING INTO AN
INITIALLY DRY AIRMASS...FORECAST SURFACE WETBULB TEMPS ARE EXPECTED
TO BE ABOVE FREEZING...YIELDING LIQUID RAINFALL. TEMPERATURES WILL
BE SLOW TO RISE ON THURSDAY AND WILL LEAN TOWARDS THE COOLER
GUIDANCE GIVEN CLOUD COVER AND SOME DIABATIC COOLING WITH
PRECIPITATION.
THURSDAY NIGHT AND FRIDAY...SIGNIFICANT DEEPENING OF THE SURFACE LOW
OVER THE MISSISSIPPI VALLEY WILL OCCUR IN RESPONSE TO A NEGATIVE
TILTING OF THE UPPER TROUGH AS IT TRANSITIONS INTO A CLOSED LOW OVER
MS/AL. ISENTROPIC LIFT WILL STRENGTHEN OVER THE REGION THROUGH
FRIDAY MORNING AS THE WARM FRONT SLOWLY LIFTS NORTHWARD AND WILL
CARRY CATEGORICAL POPS. CONFLUENT 500MB FLOW OVER THE EASTERN OHIO
VALLEY AND NORTHEAST WILL RESULT IN A STRENGTHENING SURFACE RIDGE
OVER THE MID ATLANTIC AND COLD AIR DAMMING WILL DEVELOP ACROSS VA/NC
INTO THE NORTHERN PORTION OF THE FORECAST AREA THURSDAY NIGHT INTO
FRIDAY. WETBULB TEMPERATURES DROP ACROSS THE NORTHERN MIDLANDS
FALLING BELOW FREEZING BY EARLY FRIDAY MORNING. THIS WILL LIKELY
RESULT IN A PERIOD OF FREEZING RAIN IN THE NORTHERN MIDLANDS. THERE
REMAIN SOME DIFFERENCES AMONG THE GUIDANCE ON LOW LEVEL THERMAL
PROFILES WITH THE NAM/CANADIAN BEING COLDER THAN THE GFS WHICH LEADS
TO SOME UNCERTAINTY AS TO HOW FAR SOUTH THE FREEZING RAIN MAY BE.
COMPLEX STORM SYSTEM EVOLUTION ON FRIDAY SHOWS THE INITIAL
SURFACE LOW LIFTING NORTHEASTWARD INTO EASTERN TENNESSEE WITH A
TRANSITION TO A COASTAL LOW DEVELOPING SOMEWHERE OVER EASTERN
SOUTH CAROLINA BY 00Z SATURDAY.
RELATIVELY STEADY TEMPERATURES THURSDAY NIGHT WITH CLOUDS AND
PRECIPITATION ALTHOUGH TEMPERATURES WILL LIKELY FALL ACROSS THE
NORTHERN MIDLANDS. EXPECT A STRONG GRADIENT IN TEMPERATURES ON
FRIDAY AS SURFACE LOW APPROACHES AND WARM ADVECTION OCCURS ACROSS
THE SOUTHERN PART OF THE AREA WHILE THE WEDGE HOLDS STRONG ACROSS
THE NORTH...THOUGH TEMPERATURES UP NORTH SHOULD ALSO RISE A BIT
FRIDAY AFTERNOON.
THIS LOOKS TO BE A POTENTIALLY SIGNIFICANT QPF EVENT WITH LIQUID
ACCUMULATIONS OF A 0.50-1.00 INCH WITH ACCUMULATING FREEZING RAIN
ACROSS PARTS OF THE NORTHERN MIDLANDS COUNTIES. WILL INCLUDE SOME
LIGHT ICE ACCUMULATION ACROSS THE NORTHERN MIDLANDS WITH THIS
FORECAST ISSUANCE BUT WILL HOLD OFF ON ANY HEADLINES AND ALLOW
LATER SHIFTS TO VIEW NEW DATA AND ISSUE A WATCH FOR
LANCASTER/CHESTERFIELD IF NEEDED.
FRIDAY NIGHT AND SATURDAY...SURFACE LOW DEEPENS AND MOVES UP THE
COAST TO NEAR NORFOLK BY 12Z SATURDAY WHILE THE CLOSED UPPER LOW
SLOWLY MOVES OVER THE SOUTHERN APPALACHIANS BY SATURDAY MORNING. MID
LEVEL DRY SLOT FORECAST TO MOVE OVER THE FORECAST AREA FRIDAY NIGHT
INTO EARLY SATURDAY WHICH WILL RESULT IN MUCH LOWER POPS FRIDAY
NIGHT.
THE UPPER LOW WILL DRIFT EAST ACROSS THE CAROLINAS ON SATURDAY WITH
THE CORE OF THE COLD AIR ALOFT MOVING OVER THE FORECAST AREA WITH
500MB TEMPS AS COLD AS -26C TO -27C. THE AMOUNT OF MOISTURE
ASSOCIATED WITH THE UPPER LOW IS THE MAIN UNCERTAINTY AT THIS POINT
WITH THE NAM/CANADIAN SHOWING MUCH MORE SHALLOW MOISTURE COMPARED TO
THE GFS/ECMWF. CANNOT RULE OUT SOME RAIN/SNOW MIX ON SATURDAY
ACROSS THE AREA BUT POPS WILL BE LOW AND LIQUID ACCUMULATION IS
EXPECTED TO BE LIGHT...BUT ANY ACCUMULATION IS EXPECTED TO BE
LIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO
TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON
INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA
OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME
ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE
DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO
MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS
AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER
SUNRISE THURSDAY MORNING.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH
SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
200 PM EST WED JAN 20 2016
.SYNOPSIS...
THE SURFACE PRESSURE RIDGE WILL REMAIN NEAR THE FORECAST AREA
TODAY AND HELP LIMIT MOISTURE ASSOCIATED WITH AN UPPER- LEVEL
DISTURBANCE MOVING INTO THE AREA THIS AFTERNOON. MOISTURE WILL
INCREASE THURSDAY AHEAD OF LOW PRESSURE APPROACHING FROM THE WEST.
THE LOW WILL CROSS THE AREA FRIDAY INTO FRIDAY NIGHT. DRY HIGH
PRESSURE WILL RETURN FOR SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
REST OF THE AFTERNOON...THE SURFACE RIDGE IS CURRENTLY CENTERED OVER
THE COASTAL PLAIN OF THE CAROLINAS. THE RIDGE WILL HELP LIMIT
MOISTURE ASSOCIATED WITH THE MID-LEVEL SHORTWAVE TROUGH MOVING INTO
THE FORECAST AREA. THE LATEST HRRR INDICATES PRECIPITATION
DIMINISHING AS IT MOVES INTO THE AREA FROM THE WEST THIS AFTERNOON
INTO THE EVENING. EXPECT MUCH OF THE FORECAST AREA WILL HAVE A
PERIOD OF SPRINKLES BUT THE CHANCE OF MEASURABLE PRECIPITATION
SHOULD BE LOW. THE GFS AND NAM PLUS SREF GUIDANCE DISPLAY
PRECIPITATION AMOUNTS OF 0.01 OF AN INCH OR LESS. THE GUIDANCE
CONSENSUS SUPPORTS POPS NEAR 30 PERCENT EXTREME NORTH TO 10 TO 20
PERCENT SOUTH LATER THIS AFTERNOON. THE TOP-DOWN METHOD RUN ON BOTH
THE NAM AND GFS NOW INDICATING PATCHES OF LIGHT RAIN ACROSS THE
NORTHERN AND WESTERN PORTIONS OF THE FORECAST AREA WITH LOW CHANCE
POPS. GIVEN THE POTENTIAL FOR EVAPORATIVE COOLING WITH THE CURRENT
LOW DEWPOINTS...CANNOT RULE OUT A BRIEF MIX OF SOME SNOW WITH THE
RAIN ACROSS PORTIONS IN THE EXTREME NORTH LATER THIS AFTERNOON...BUT
NO ACCUMULATIONS ARE EXPECTED.
FOR TONIGHT...MOISTURE WILL FURTHER DIMINISH BEHIND THE MID-LEVEL
SHORTWAVE TROUGH THIS EVENING. THE NAM AND GFS TIME-HEIGHT DISPLAYS
INDICATE LINGERING LOW-LEVEL MOISTURE BELOW THE SNOW-GROWTH ZONE.
FORECASTED A SLIGHT RAIN CHANCE IN THE EVENING BASED ON THE HRRR AND
SPC WRF. LITTLE CONVERGENCE WILL BE ASSOCIATED WITH THE COLD FRONT
LATE. WILL KEEP A LOW CHANCE POP MAINLY IN THE CSRA LATE TONIGHT.
OVERNIGHT LOWS RANGING FROM NEAR 30 EXTREME NORTH TO NEAR 40
SOUTH.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
LOW PRESSURE OVER TEXAS THURSDAY MORNING WILL LIFT NORTHEAST
ACROSS THE LOWER MS RIVER VALLEY THROUGH THURSDAY NIGHT. ITS
ASSOCIATED WARM FROM WILL REMAIN SOUTH OF THE CSRA. INCREASING
ISENTROPIC LIFT AHEAD OF THE WARM FRONT WILL SPREAD RAIN INTO THE
AREA...MAINLY AFFECTING THE CSRA AND WESTERN MIDLANDS DURING THE
DAY WITH RAIN CHANCES INCREASING THURSDAY NIGHT AS THE LOW
PRESSURE SYSTEM LIFTS NORTHEAST.
MODELS INDICATE WEAK IN-SITU COLD AIR DAMMING DEVELOPING ACROSS
THE NORTH AND CENTRAL MIDLANDS THURSDAY NIGHT. TEMPERATURES MAY
BE NEAR FREEZING ACROSS PORTIONS OF LANCASTER AND CHESTERFIELD
COUNTIES. THE NAM AND ECMWF MODELS ARE COLDER THAN THE GFS IN THE
1000 MB TO 850 THICKNESS ACROSS THE NORTH MIDLANDS FRIDAY. SREF
SHOW LOW PROBABILITIES FOR FREEZING RAIN IN THAT REGION. WILL
MENTION A SLIGHT CHANCE FREEZING RAIN FOR FRIDAY MORNING. THIS
REMAINS A LOW CONFIDENCE FORECAST.
WENT NEAR GUIDANCE CONSENSUS FOR HIGH TEMPERATURES ON THURSDAY
RANGING FROM THE MID 40S NORTH TO AROUND 50 SOUTH. LOWS ARE
EXPECTED TO BE IN THE LOWER 30S NORTH TO THE MID 40S SOUTH.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODELS ARE IN FAIRLY GOOD AGREEMENT AND CONTINUE TO COME TOWARD A
CONSENSUS WITH THE LOW PRESSURE SYSTEM CROSSING THE AREA FRIDAY
THROUGH SATURDAY. THE GFS IS SLIGHTLY FASTER THAN THE ECMWF.
THE STORM SYSTEM WILL TRACK ACROSS THE REGION FRIDAY PROVIDING
WIDESPREAD PRECIPITATION. THE AREA OF LOW PRESSURE SHOULD MOVE
EAST OF THE MIDLANDS FRIDAY NIGHT THEN TURN NORTHEASTWARD AND
MOVE ALONG TO THE MID ATLANTIC COAST SATURDAY. AS LOW PRESSURE
SYSTEM DEEPENS OFF THE NC/VA COAST LATE FRIDAY NIGHT...PARTIAL
THICKNESS SCHEMES SUGGEST WINTRY PRECIPITATION POSSIBLE ACROSS THE
NORTHERN AND WESTERN MIDLANDS AS WELL AS THE PIEDMONT...ALTHOUGH
MOISTURE MAY BE SHALLOW. ALTHOUGH QPF VALUES WILL BE LOW HAVE
REMAINED WITH THE POTENTIAL RAIN/SNOW MIXTURE ASSOCIATED WITH WRAP
AROUND MOISTURE. UNCERTAINTY REMAINS QUITE HIGH. HIGH PRESSURE AND
DRIER AIR WILL RETURN TO THE REGION FOR SUNDAY AND MONDAY WITH THE
NEXT LOW PRESSURE SYSTEM WILL PUSH A COLD FRONT TOWARD THE AREA
MONDAY NIGHT.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. THE DRY SURFACE
PRESSURE RIDGE WILL CONTINUE TO EXTEND INTO THE AREA. A MID-LEVEL
SHORTWAVE TROUGH WILL HELP SUPPORT VFR CEILINGS THIS AFTERNOON INTO
TONIGHT. THERE MAY ALSO BE A PERIOD OF SPRINKLES LATE THIS AFTERNOON
INTO THE EVENING. THE HRRR CONTINUES TO DISPLAY A DIMINISHING AREA
OF PRECIPITATION MOVING INTO THE AREA FROM THE WEST DURING THAT TIME
ASSOCIATED WITH THE UPPER-LEVEL FEATURE. A FEW SPRINKLES POSSIBLE
DURING THE OVERNIGHT HOURS IN THE CSRA BUT NOT ENOUGH CONFIDENCE TO
MENTION AT THIS TIME. WINDS WILL BE MAINLY LIGHT AND VARIABLE THIS
AFTERNOON THROUGH TONIGHT...BECOMING LIGHT FROM THE EAST AFTER
SUNRISE THURSDAY MORNING.
EXTENDED AVIATION OUTLOOK....A LOW PRESSURE SYSTEM MAY BRING
WIDESPREAD MVFR OR IFR CONDITIONS THURSDAY AFTERNOON THROUGH
SATURDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
104 PM EST WED JAN 20 2016
.PREV DISCUSSION... /ISSUED 1058 AM EST WED JAN 20 2016/
.UPDATE...
IMPRESSIVE BAND OF HEAVIER PRECIP IMPINGING INTO NW CWA WITH SOME
LIGHT MORE ISOLATED RETURNS AHEAD OF ASSOCIATED DISTURBANCE. SO
FAR HAVE HAD SOME REPORTS OF FZRA AND SLEET BUT MAINLY IN FAR
NORTH AND MAIN CONCERN OF IMPACTFUL ACCUMULATIONS WILL BE WITH
APPROACHING BAND AS EVAP COOLING MECHANISM HAS SHOWN SOME SFC TEMP
DROPS OF 2-3 DEG. GIVEN THE STILL LOW DWPTS ACROSS THE FAR
NORTHERN TIER WITH VALUES STILL IN UPPER TEENS TO LOW 20S AT SOME
SPOTS...COULD SEE SOME ISOLATED HIGHER ICE ACCUMULATIONS AROUND
0.25 INCHES. ALSO THE HRRR SO FAR LOOKS TO HAVE DECENT HOLD ON
TRENDS WITH P-TYPE AND HAVE ADJUSTED POPS AND WINTER GRIDS
ACCORDINGLY. HRRR PROGGED WETBULB TEMPS KEEP THE NE HIGHER
ELEVATIONS AROUND 30 DEG THROUGH THE AFTERNOON ALONG WITH A
TRANSITION FROM INITIAL MIXED P-TYPE TO PRIMARILY SNOW SO HAVE
INCREASED THE LOWER BOUND SNOW AMOUNTS TO NEAR HALF AN INCH
SLIGHTLY FARTHER SOUTHEAST TO NEAR GAINESVILLE AND EASTWARD. AS
FAR AS NEAR THE METRO...OVERNIGHT TEMPS WERE THANKFULLY ABOUT 4
DEGREES WARMER THAN FCST SO TRENDS HAVE BEEN TO RISE TO 34-36
DEGREES FROM THE WEST. ALL IN ALL HAVE NOT ADJUSTED ANY EXTENT OR
TIMING TO THE CURRENT ADVISORY AND WARNING AREAS. PREVIOUS
DISCUSSION FOLLOWS...
BAKER
&&
PREV DISCUSSION... /ISSUED 652 AM EST WED JAN 20 2016/
PREV DISCUSSION... /ISSUED 437 AM EST WED JAN 20 2016/
.SHORT TERM /TODAY THROUGH THURSDAY/...
SHORT TERM FORECAST CONTINUES TO BE A CHALLENGE WITH IMPACTFUL
WINTRY PRECIPITATION EXPECTED ACROSS NORTH GEORGIA. UPPER LEVEL
DISTURBANCE WILL INTERACT WITH COLD AND DRY CONDITIONS ACROSS THE
AREA TO PRODUCE A WINTRY MIX OVER PORTIONS OF NORTH GEORGIA.
ALTHOUGH MODELS HAVE SLOWED THE ONSET TIMING SLIGHTLY BY AN HOUR OR
SO...CONSENSUS IS THAT PRECIPITATION WILL BEGIN AS SNOW THIS
MORNING...THEN TRANSITION TO FREEZING RAIN/SLEET AND THEN TRANSITION
TO ALL SNOW IN THE NE MOUNTAINS BY THE AFTERNOON. ACCUMULATING
WINTRY MIX IS EXPECTED AS FAR SOUTH AS PORTIONS OF THE NORTHERN
ATLANTA SUBURBS...BUT STILL COULD SEE SOME NON-ACCUMULATING MIX AS
FAR SOUTH AS I-20. ALREADY SEEING SOME LIGHT RETURNS ON RADAR ACROSS
AL/NORTHERN GEORGIA...BUT SO FAR NOTHING REACHING THE GROUND.
MODELS CONTINUE TO SUGGEST THIS TO BE AN OVERALL LOW QPF
EVENT...WITH LIQUID EQUIVALENT ONLY A QUARTER INCH OR LESS. WPC WWD
GUIDANCE HAS BACKED OFF SOMEWHAT ON SNOWFALL TOTALS...BUT HAS SPREAD
THE ACCUMULATING FREEZING RAIN AMOUNTS FARTHER SOUTH. GIVEN THE
TIMING OF THE PRECIPITATION ONSET AND THE EXPECTED WARMING
TEMPERATURES /PARTICULARLY ACROSS THE METRO AREA/ HAVE OPTED NOT TO
DEVIATE TOO FAR FROM THE PREVIOUS SNOW/ICE AMOUNTS PREVIOUSLY
FORECAST...A LITTLE MORE CONSERVATIVE IN AREAL COVERAGE THAN THE WWD
ICE GRID.
THE WINTER STORM WARNING AND THE WINTER WEATHER ADVISORY CONTINUE
WITH NO CHANGES MADE TO THE TIMING OR AREA. STILL ANTICIPATE UP TO 2-
2.5 INCHES OF SNOW IN THE WSW /PARTICULARLY IN THE NE GA MOUNTAINS/
AND UP TO A TENTH OF AN INCH OF ICE. IN THE ADVISORY AREA UP TO 1
INCH OF SNOW AND A TENTH OF AN INCH OF ICE CAN BE EXPECTED. WITH
COLD ANTECEDENT CONDITIONS...IMPACTS ARE EXPECTED AT ONSET OF THE
PRECIPITATION. HAVE ALSO CONTINUED THE SPECIAL WEATHER STATEMENT FOR
SEVERAL COUNTIES JUST SOUTH OF THE ADVISORY AREA TO INDICATE
POTENTIAL FOR WINTRY PRECIPITATION MIXED WITH RAIN.
THERE REMAINS SEVERAL UNCERTAINTIES WITH THE FORECAST THAT WILL NEED
TO BE MONITORED AS THE EVENT UNFOLDS. THE WEAKENING RIDGE AND
EROSION OF THE ASSOCIATED LOW LEVEL INVERSION WILL PLAY A KEY ROLE
IN DURATION OF WINTER PRECIP. THERMODYNAMIC TRENDS WILL STILL NEED
TO BE WATCHED FOR WETBULBING/EVAPORATIVE COOLING EFFECTS AND IF IT
DELAYS THE TRANSITION TO OTHER P-TYPES. LINGERING FREEZING
TEMPERATURES INTO THE OVERNIGHT HOURS COULD ALLOW FROZEN PRECIP TO
CONTINUE AND INCREASE BLACK ICE THREAT.
STAY TUNED AS THE FORECAST CONTINUES TO EVOLVE AS THE EVENT UNFOLDS.
ALTHOUGH THE PRECIPITATION POTENTIAL DIMINISHES SOMEWHAT
OVERNIGHT...ALL RAIN WILL RETURN TO THE AREA THURSDAY AND INTO THE
INITIAL EXTENDED FORECAST PERIODS. ANTICIPATE THAT BY MID MORNING
THURSDAY ALL OF NORTH AND CENTRAL GEORGIA SHOULD BE SEEING ABOVE-
FREEZING TEMPERATURES.
31
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
SOUTHERN STREAM LOW MOVING INTO THE LOWER MS VALLEY AT THE START
OF THE PERIOD...TRACKING THROUGH THE TN VALLEY AND THEN OFF THE
MID ATLANTIC COAST BY SATURDAY MORNING. EXPECTING ALL LIQUID
PRECIP UNTIL FRIDAY NIGHT AS WRAP AROUND MOISTURE SPREADS INTO THE
FORECAST AREA. PARTIAL THICKNESS VALUES WOULD SUPPORT SNOW FOR THE
FAR NORTH AND A MIX OF RAIN AND SNOW FOR THE REMAINDER OF NORTH.
FOR NOW...HAVE KEPT LIGHT ACCUMULATIONS CONFINED TO THE FAR NORTH
SINCE ACTUAL QPF IS STILL QUESTIONABLE. SOME LIGHT WRAP AROUND SNOW
IS POSSIBLE SATURDAY FOR THE EXTREME NORTH AS THE LOW CONTINUES TO
MOVE NORTHEAST. SUNDAY LOOKS DRY BUT THE NEXT LOW IS MOVING INTO
THE MID MS VALLEY BY MONDAY...BRINGING MOISTURE BACK INTO THE
FORECAST AREA. PRECIPITATION SHOULD SPREAD ACROSS NORTH AND
CENTRAL GEORGIA MONDAY AND TUESDAY. LOOKING FOR ALL RAIN MONDAY
AND TUESDAY...HOWEVER LEADING INTO TUESDAY NIGHT THERE IS ANOTHER
CHANCE FOR SOME FREEZING OR FROZEN PRECIP ACROSS FAR NORTH
GEORGIA.
41
&&
.AVIATION...
18Z UPDATE...
INITIAL VFR CONDITIONS SHOULD DEGRADE TO MVFR CIGS BEHIND AREA OF
PRECIP PUSHING EASTWARD THEN IFR CIGS WITH VSBYS IN MVFR/IFR RANGE
AFTER ABOUT 08Z TONIGHT WITH LITTLE TO NO IMPROVEMENT FOR THURSDAY
AFTERNOON. COULD HAVE LINGERING -DZ OVERNIGHT THEN BETTER CHANCE
FOR WIDESPREAD -RA OR -SHRA AGAIN THURSDAY. ANY WINTRY PRECIP
POTENTIAL SHOULD STAY NORTH OF THE TAF SITES INTO THIS EVENING.
WINDS COULD SEE SSW SHIFT IN INITIAL 3-4 HRS THEN BACK TO SE/E
THRU REST OF PERIOD. MAGNITUDES 7-8 KTS BECOMING LIGHT TO CALM
OVERNIGHT AND UNDER 7 KTS FOR THURSDAY.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON ALL ELEMENTS.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 41 33 43 38 / 70 70 70 90
ATLANTA 42 37 47 42 / 80 70 70 90
BLAIRSVILLE 35 31 45 36 / 90 40 70 90
CARTERSVILLE 38 33 46 40 / 90 50 70 90
COLUMBUS 50 43 59 49 / 60 70 60 90
GAINESVILLE 35 32 42 37 / 90 60 70 90
MACON 50 40 54 45 / 40 50 50 70
ROME 37 34 46 41 / 90 30 80 90
PEACHTREE CITY 44 35 49 43 / 70 70 70 90
VIDALIA 54 41 57 47 / 20 20 30 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 AM EST THURSDAY FOR THE FOLLOWING
ZONES: CATOOSA...CHATTOOGA...DADE...DAWSON...FANNIN...GILMER...
GORDON...LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...WALKER...
WHITE...WHITFIELD.
WINTER WEATHER ADVISORY UNTIL 1 AM EST THURSDAY FOR THE
FOLLOWING ZONES: BANKS...BARTOW...CHEROKEE...FLOYD...FORSYTH...
HALL.
&&
$$
SHORT TERM...31/BAKER
LONG TERM....41
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
133 PM CST WED JAN 20 2016
.UPDATE...
1051 AM CST
FOR MORNING UPDATE...
SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR
NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE
OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO
AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE
BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT
ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN
DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED
DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY
CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR
NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO
SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22
WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH
PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE
WINDY/COLD OF THE PAST FEW DAYS.
RATZER
&&
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
133 PM CST
THURSDAY NIGHT THROUGH WEDNESDAY...
MAIN CONCERN FOR THE LONGER TERM FORECAST PERIOD REMAINS THE CHANCES
FOR LAKE EFFECT SNOW FRIDAY THROUGH FRIDAY NIGHT.
IN THE MEAN TIME...THURSDAY NIGHT SHOULD START OUT THE LONG TERM
FORECAST PERIOD RELATIVELY QUIET AS THE REGION WILL BE BETWEEN A
LARGE AREA OF HIGH PRESSURE EXTENDING FROM THE NORTHERN PLAINS
THROUGH THE GREAT LAKES AND A DEEPENING LOW PRESSURE SYSTEM MOVES
THROUGH THE LOWER MISSISSIPPI VALLEY. WINDS WILL BEGIN TO SET UP
NELY...LEADING INTO THE PERIOD OF LAKE EFFECT SNOW EXPECTED FOR
FRIDAY. BY MIDDAY FRIDAY...THE HIGH WILL EXTEND FROM THE UPPER
GREAT LAKES THROUGH THE SOUTH HIGH PLAINS WHILE LOW PRESSURE DEEPENS
OVER THE SERN CONUS. A RELATIVE WEAKNESS IN THE PRESSURE GRADIENT IS
EXPECTED TO DEVELOP ACROSS LOWER MICHIGAN...LAKE MICHIGAN AND INTO
NRN ILLINOIS. WHILE THE GENERAL PATTERN WILL BE CONDUCIVE FOR LAKE
EFFECT SNOW FOR NERN IL...POSSIBLY EXTENDING INTO FAR NWRN INDIANA
ARND GYY...THE GREATEST LAKE INDUCED INSTABILITY SHOULD BE DURG THE
DAYTIME HOURS ON FRIDAY WHEN INVERSION HEIGHTS WILL BE ARND 5KFT AND
SFC TO 850MB DELTA-T SHOULD BE ARND 13C UNDER NELY WINDS. WHILE THE
LONGER TERM GUIDANCE MAY LACK THE RESOLUTION OF THE SHORT TERM
GUIDANCE...THE GFS/ECMWF ALSO INDICATE A CONVERGENCE BAND OVER THE
SWRN PORTION OF LAKE MICHIGAN...FURTHER AIDING CONFIDENCE IN AT
LEAST SOME LAKE EFFECT SNOW ACCUMULATION. WEAK CONVERGENCE IS
EXPECTED TO CONTINUE INTO FRIDAY NIGHT...BUT THE FOCUS SHOULD SHIFT
A LITTLE NORTH INTO SERN WISCONSIN. ALSO...LOW LEVEL INVERSION
HEIGHTS AND INSTABILITY SHOULD DIMINISH THROUGH THE NIGHT...PER
LATEST MODEL SOUNDINGS...SO EXPECT THE LAKE EFFECT SNOW POTENTIAL TO
END BY SATURDAY MORNING. GIVEN WEAK FORCING AND MARGINAL LOW LEVEL
INSTABILITY ALONG WITH A PROGRESSIVE CONVERGENCE ZONE...SNOW
ACCUMULATIONS SHOULD BE LIGHT...GENERALLY UNDER AN INCH.
FOR THE REMAINDER OF THE WEEKEND...THE AREA OF HIGH PRESSURE SHOULD
MOVE ACROSS THE REGION...SETTLING INTO THE OHIO VALLEY SUNDAY NIGHT.
EXPECT AMPLE SUNSHINE AND HIGHS IN THE LOWER 30S FOR SATURDAY AND
THE MIDDLE 30S SUNDAY. RELATIVELY MILD CONDITIONS SHOULD CONTINUE
INTO MONDAY AS BROAD...DIFFUSE LOW PRESSURE ASSOCIATED WITH A
SOUTHERN STREAM SHORTWAVE...REACHES THE MIDDLE MISSISSIPPI
VALLEY...WITH A ZONE OF BROAD WARM/MOIST ADVECTION AHEAD OF THE WEAK
LOW. THIS SYSTEM SHOULD BRING THE NEXT CHANCE OF PCPN...STARTING
OUT AS A MIX OF RAIN AND SNOW SHOWERS MONDAY WITH SOME LINGERING
LIGHT SNOW SHOWERS POSSIBLE INTO MONDAY NIGHT OR TUESDAY. CURRENT
INDICATORS SUGGEST WEAK SFC FORCING AND MODERATE ISENTROPIC LIFT
AHEAD OF AN ASSOCIATED COLD FRONT...SO...PCPN AMOUNTS SHOULD BE
RELATIVELY LIGHT.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CEILINGS TODAY...POSSIBLY PERSISTING INTO TONIGHT.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
WHILE VFR CEILINGS CONTINUE TO MOVE ACROSS THE
TERMINALS...DIURNALLY DRIVEN MVFR CEILINGS HAVE DEVELOPED TODAY.
HAVE HIGHER CONFIDENCE WITH THESE LOWER CEILINGS TO REMAIN
OVERHEAD THIS AFTERNOON OR AT LEAST CONTINUE TO PERIODICALLY MOVE
ACROSS THE TERMINALS BUT CONFIDENCE LOWERS INTO THIS EVENING WITH
SOME POTENTIAL FOR THEM TO REMAIN. AT THIS TIME...LIKELY SCENARIO
WILL BE FOR THEM TO SCATTER EARLY THIS EVENING. HOWEVER...ONCE
AGAIN WEATHER PATTERN TONIGHT COULD ALLOW FOR REDEVELOPMENT
OVERNIGHT. ALSO...HAVE LEFT OUT ANY FOG MENTION TONIGHT BUT THERE
WILL BE POTENTIAL FOR AT LEAST SOME ISOLATED MVFR VIS/FOG TO
DEVELOP. HIGH PRESSURE OVERHEAD THROUGH THE PERIOD WILL ALLOW FOR
MAINLY LIGHT AND VARIABLE WINDS BUT WHEN THE WINDS DO HOLD ONTO A
DIRECTION...WILL LIKELY BE SOME LIGHT WESTERLY COMPONENT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH WITH WIND SPEED/DIRECTION.
* MEDIUM HIGH WITH CEILINGS THIS AFTERNOON...LOW MEDIUM THIS
EVENING/TONIGHT.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS.
FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY
NORTHEAST WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR.
TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
KJB
&&
.MARINE...
106 PM CST
RELATIVELY QUIET WEATHER EXPECTED ACROSS LAKE MICHIGAN OVER THE
NEXT SEVERAL DAYS...WITH THE ONLY PERIOD OF NOTE BEING FRIDAY AND
FRIDAY NIGHT AS WINDS TURN NORTH-NORTHEAST AND INCREASE INTO THE
20-25 KT RANGE PARTICULARLY ON THE SOUTHERN HALF OR SO OF THE
LAKE. THIS WILL BE IN RESPONSE TO AN AREA OF LOW PRESSURE WHICH
WILL DEVELOP ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY...WHICH IS FORECAST TO DEEPEN AND MOVE NORTHEAST ACROSS THE
GULF STATES/LOWER TENNESSEE VALLEY FRIDAY BEFORE REDEVELOPING
ALONG THE MID-ATLANTIC COAST ON SATURRDAY AND MOVING NORTHEAST OFF
THE NEW ENGLAND COAST ON SUNDAY. WINDS ON LAKE MICHIGAN LOOK TO
INCREASE FRIDAY AFTERNOON...THEN WEAKEN LATE FRIDAY NIGHT/EARLY
SATURDAY AS A RIDGE OF HIGH PRESSURE MOVES OVER THE
WESTERN/NORTHERN LAKES. OTHERWISE...LONGER RANGE MODEL GUIDANCE
INDICATES ANOTHER WEAKER LOW PRESSURE SYSTEM MAY DEVELOP OVER THE
SOUTH-CENTRAL PLAINS SUNDAY NIGHT...MOVING TO THE GREAT LAKES
REGION BY LATE MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
107 PM CST WED JAN 20 2016
.UPDATE...
1051 AM CST
FOR MORNING UPDATE...
SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR
NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE
OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO
AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE
BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT
ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN
DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED
DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY
CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR
NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO
SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22
WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH
PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE
WINDY/COLD OF THE PAST FEW DAYS.
RATZER
&&
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CEILINGS TODAY...POSSIBLY PERSISTING INTO TONIGHT.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
WHILE VFR CEILINGS CONTINUE TO MOVE ACROSS THE
TERMINALS...DIURNALLY DRIVEN MVFR CEILINGS HAVE DEVELOPED TODAY.
HAVE HIGHER CONFIDENCE WITH THESE LOWER CEILINGS TO REMAIN
OVERHEAD THIS AFTERNOON OR AT LEAST CONTINUE TO PERIODICALLY MOVE
ACROSS THE TERMINALS BUT CONFIDENCE LOWERS INTO THIS EVENING WITH
SOME POTENTIAL FOR THEM TO REMAIN. AT THIS TIME...LIKELY SCENARIO
WILL BE FOR THEM TO SCATTER EARLY THIS EVENING. HOWEVER...ONCE
AGAIN WEATHER PATTERN TONIGHT COULD ALLOW FOR REDEVELOPMENT
OVERNIGHT. ALSO...HAVE LEFT OUT ANY FOG MENTION TONIGHT BUT THERE
WILL BE POTENTIAL FOR AT LEAST SOME ISOLATED MVFR VIS/FOG TO
DEVELOP. HIGH PRESSURE OVERHEAD THROUGH THE PERIOD WILL ALLOW FOR
MAINLY LIGHT AND VARIABLE WINDS BUT WHEN THE WINDS DO HOLD ONTO A
DIRECTION...WILL LIKELY BE SOME LIGHT WESTERLY COMPONENT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH WITH WIND SPEED/DIRECTION.
* MEDIUM HIGH WITH CEILINGS THIS AFTERNOON...LOW MEDIUM THIS
EVENING/TONIGHT.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS.
FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY
NORTHEAST WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR.
TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
KJB
&&
.MARINE...
106 PM CST
RELATIVELY QUIET WEATHER EXPECTED ACROSS LAKE MICHIGAN OVER THE
NEXT SEVERAL DAYS...WITH THE ONLY PERIOD OF NOTE BEING FRIDAY AND
FRIDAY NIGHT AS WINDS TURN NORTH-NORTHEAST AND INCREASE INTO THE
20-25 KT RANGE PARTICULARLY ON THE SOUTHERN HALF OR SO OF THE
LAKE. THIS WILL BE IN RESPONSE TO AN AREA OF LOW PRESSURE WHICH
WILL DEVELOP ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI
VALLEY...WHICH IS FORECAST TO DEEPEN AND MOVE NORTHEAST ACROSS THE
GULF STATES/LOWER TENNESSEE VALLEY FRIDAY BEFORE REDEVELOPING
ALONG THE MID-ATLANTIC COAST ON SATURRDAY AND MOVING NORTHEAST OFF
THE NEW ENGLAND COAST ON SUNDAY. WINDS ON LAKE MICHIGAN LOOK TO
INCREASE FRIDAY AFTERNOON...THEN WEAKEN LATE FRIDAY NIGHT/EARLY
SATURDAY AS A RIDGE OF HIGH PRESSURE MOVES OVER THE
WESTERN/NORTHERN LAKES. OTHERWISE...LONGER RANGE MODEL GUIDANCE
INDICATES ANOTHER WEAKER LOW PRESSURE SYSTEM MAY DEVELOP OVER THE
SOUTH-CENTRAL PLAINS SUNDAY NIGHT...MOVING TO THE GREAT LAKES
REGION BY LATE MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1154 AM CST WED JAN 20 2016
.UPDATE...
1051 AM CST
FOR MORNING UPDATE...
SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR
NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE
OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO
AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE
BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT
ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN
DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED
DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY
CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR
NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO
SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22
WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH
PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE
WINDY/COLD OF THE PAST FEW DAYS.
RATZER
&&
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CEILINGS TODAY...POSSIBLY PERSISTING INTO TONIGHT.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
WHILE VFR CEILINGS CONTINUE TO MOVE ACROSS THE
TERMINALS...DIURNALLY DRIVEN MVFR CEILINGS HAVE DEVELOPED TODAY.
HAVE HIGHER CONFIDENCE WITH THESE LOWER CEILINGS TO REMAIN
OVERHEAD THIS AFTERNOON OR AT LEAST CONTINUE TO PERIODICALLY MOVE
ACROSS THE TERMINALS BUT CONFIDENCE LOWERS INTO THIS EVENING WITH
SOME POTENTIAL FOR THEM TO REMAIN. AT THIS TIME...LIKELY SCENARIO
WILL BE FOR THEM TO SCATTER EARLY THIS EVENING. HOWEVER...ONCE
AGAIN WEATHER PATTERN TONIGHT COULD ALLOW FOR REDEVELOPMENT
OVERNIGHT. ALSO...HAVE LEFT OUT ANY FOG MENTION TONIGHT BUT THERE
WILL BE POTENTIAL FOR AT LEAST SOME ISOLATED MVFR VIS/FOG TO
DEVELOP. HIGH PRESSURE OVERHEAD THROUGH THE PERIOD WILL ALLOW FOR
MAINLY LIGHT AND VARIABLE WINDS BUT WHEN THE WINDS DO HOLD ONTO A
DIRECTION...WILL LIKELY BE SOME LIGHT WESTERLY COMPONENT.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH WITH WIND SPEED/DIRECTION.
* MEDIUM HIGH WITH CEILINGS THIS AFTERNOON...LOW MEDIUM THIS
EVENING/TONIGHT.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS.
FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY
NORTHEAST WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR.
TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
KJB
&&
.MARINE...
100 AM CST
SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT
WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY
FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE
SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS
AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE
UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER
NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE
LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT
ADVISORY FOR THE ILLINOIS AND INDIANA NEAR SHORES.
HOWEVER...THERE ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR
SHORES DUE TO THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO
BE MONITORED OVER THE NEXT COUPLE DAYS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1051 AM CST WED JAN 20 2016
.UPDATE...
1051 AM CST
FOR MORNING UPDATE...
SECONDARY VORT/MID-LEVEL SHORT WAVE TROUGH MOVE ACROSS FAR
NORTHEAST IL/SOUTHERN LAKE MICHIGAN THROUGH LATE MORNING WILL MOVE
OFF TO THE EAST THIS AFTERNOON...BRINING ANY LINGERING FLURRIES TO
AN END IN THE NEXT HOUR OR TWO. RISING HEIGHTS AND SUBSIDENCE
BEHIND DEPARTING SHORT WAVE WILL HELP THIN CLOUD COVER SOMEWHAT
ESPECIALLY OVER WEST/SOUTH PARTS OF THE CWA AS IS CURRENTLY SEEN
DEVELOPING IN VIS SATELLITE IMAGERY...THOUGH LOW STRATOCU NOTED
DEVELOPING UPSTREAM WHICH WILL LIKELY MAINTAIN PARTLY SUNNY
CONDITIONS AT BEST AND PERHAPS MORE MOSTLY CLOUDY ACROSS FAR
NORTHEAST IL WHERE MORE EXTENSIVE CLOUD COVER EXISTS UPSTREAM INTO
SOUTHERN WI. OTHERWISE...TEMPS ON TRACK FOR AFTERNOON HIGHS 19-22
WHICH WITH LIGHT/VARIABLE WINDS UNDER DEVELOPING SURFACE HIGH
PRESSURE SHOULD MAKE IT FEEL A WHOLE LOT BETTER THAN THE
WINDY/COLD OF THE PAST FEW DAYS.
RATZER
&&
.SHORT TERM...
313 AM CST
THROUGH THURSDAY...
PRIMARY CONCERN IN THE SHORT TERM IS ESCORTING THE SNOW OUT OF THE
CWA IN THE GRIDS EARLY THIS MORNING. BACK EDGE OF THE LIGHTLY
ACCUMULATING SNOW IS MAKING STEADY PROGRESS EAST AND SHOULD SEE AN
END TO THREAT OF ACCUMULATIONS BY 10-11Z IN CHICAGO AREA AND BY
12Z OVER NW INDIANA. WHILE MOST OF THE SNOW SHOULD END JUST PRIOR
TO RUSH HOUR...RADAR AND SURFACE OBS UPSTREAM DO INDICATE A SOME
SCATTERED LINGERING FLURRIES NORTHWEST BACK TO THE TROUGH AXIS
OVER SOUTHERN WISCONSIN/NE IA AND SE MN. HAVE ADDED SOME FLURRIES
INTO THROUGH 15Z...THOUGH RAP RH PROGS SUGGEST THAT FLURRIES COULD
POTENTIALLY EVEN LINGER A BIT LONGER BUT WILL LET DAY SHIFT EXTEND
THE MENTION IF NEEDED. ONCE FLURRIES END SHOULD REMAIN CLOUDY
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD WITH ONLY SMALL
DIURNAL SWINGS IN TEMPS. GIVEN THE EXPECTED CLOUD COVER AND WEAK
THERMAL ADVECTION HAVE LEANED TOWARD THE COOLER SIDE OF GUIDANCE
FOR HIGH TEMPS AND TOWARD THE WARMER SIDE OF GUIDANCE FOR LOW
TEMPS.
IZZI
&&
.LONG TERM...
313 AM CST
THURSDAY NIGHT THROUGH TUESDAY...
ABOUT THE ONLY THING TO TALK ABOUT IN THE LONG TERM IS THE LAKE
EFFECT POTENTIAL ON FRIDAY INTO FRIDAY EVENING.
OVERALL...CONTINUES TO LOOK LIKE A MARGINAL SET-UP AT BEST.
POWERFUL AND DEEPENING SOUTHERN STREAM CYCLONE TRACKING ACROSS THE
SOUTHEASTERN CONUS WILL RESULT IN AN INCREASING NORTH-NORTHEAST
FLOW DOWN THE FULL FETCH OF THE LAKE. DESPITE THE FAVORABLE WIND
DIRECTION AND THE FACT THAT MOST OF THE MODELS DO ATTEMPT TO SPIT
OUT SOME QPF...MOST OTHER FACTORS LOOK EITHER MARGINAL OR
UNFAVORABLE FOR LAKE EFFECT. STRONG SOUTHERN STORM SYSTEM IS NOT
PHASED WITH THE POLAR JET...SO WHILE IT IS TRACKING EAST MID-UPPER
LEVEL HEIGHTS ARE ALREADY RISING FRIDAY IN OUR NECK OF THE WOODS
AS NORTHERN STREAM SHORTWAVE RIDGING BUILDS EAST. THE RISING
HEIGHTS WILL ACT TO RE-ENFORCE SUBSIDENCE/FRONTAL INVERSION WHICH
IS PROGGED TO PEAK AROUND 5KFT AGL. AMBIENT TEMPS AT THE LAKE
INDUCED EQUILIBRIUM LEVEL ARE ONLY FORECAST TO BE IN THE -10 TO
-12C RANGE...SO ITS QUESTIONABLE IF ICE NUCLEI WILL EVEN BE
PRESENT FOR SNOW AND MORE LIKELY THAN NOT ANYTHING THAT FALLS
COULD BE LIGHT SNOW GRAIN SHOWERS. WHAT INSTABILITY THAT DOES
EXIST BELOW THE SHALLOW INVERSION IS ALSO WEAK AND NOT FAVORABLE
FOR LAKE EFFECT. GIVEN THE PERPONDERANCE OF THE EVIDENCE AGAINST
MEANINGFUL LAKE EFFECT SNOW HAVE MAINTAINED JUST LOW CHANCE POPS
FOR SOME LIGHT SNOW SHOWERS OR FLURRIES.
AFTER EXTENDED PERIOD OF CLOUD COVER LOOK FOR CLOUDINESS TO
GRADUALLY BREAK UP FOR A TIME OVER THE WEEKEND BRIEFLY. THE SLOW
MODERATION IN TEMPS WILL ALSO CONTINUE THROUGH THE WEEKEND...TO
THE POINT WE SHOULD BE A BIT ABOVE SEASONAL NORMS BY THE
WEEKEND...PARTICULARLY NIGHTTIME LOWS. WHILE DETAILS VARY IN HOW
IT EVOLVES...BOTH GFS AND ECMWF SUGGEST A SYSTEM WILL AFFECT THE
REGION EARLY NEXT WEEK. A BIT TOO FAR OUT AT THIS POINT TO PIN
DOWN P-TYPE AS IT DOES LOOK LIKE WE COULD END UP ON EITHER SIDE OF
THE RAIN/SNOW LINE DEPENDING ON EVENTUAL TRACK/INTENSITY OF THE
SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* LINGERING LIGHT SNOW/FLURRIES OVER THE NEXT 1-2 HOURS.
* MVFR CIGS REDEVELOPING.
KJB/RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
THE ACCUMULATING SNOW HAS COME TO AN END. HOWEVER...A FEW
LINGERING FLURRIES COULD LINGER FOR THE NEXT FEW HOURS...BUT NO
IMPACTS ARE EXPECTED. OTHERWISE...IT APPEARS THAT A PERIOD OF VFR
CIGS OF 4-6 KFT AGL WILL BE THE RULE FOR THE NEXT FEW
HOURS...BEFORE SOME LOWER MVFR CIGS REDEVELOP OVER THE AREA BY
LATE MORNING. THESE LOWER CIGS COULD HANG ACROSS MUCH OF THE AREA
THROUGH THE DAY.
THERE IS A SMALL CHANCE OF SOME FOG DEVELOPMENT LATE
TONIGHT...PARTICULARLY AT KRFD AND KDPA. HOWEVER...THERE IS
UNCERTAINTY DUE TO THE POSSIBILITY OF CLOUD COVER. THEREFORE...I
HAVE LEFT THE MENTION OUT OF THE TAFS AT THIS TIME.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH WITH SNOW TRENDS.
* MEDIUM WITH CEILING TRENDS.
KJB/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...MAINLY VFR. LIGHT NORTH- NORTHEASTERLY WINDS.
FRIDAY...SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND MVFR/IFR. BREEZY
NORTHEAST WINDS.
SATURDAY...VFR. NORTH-NORTHEAST WINDS TURNING SOUTHWEST.
SUNDAY...VFR. SOUTHWEST WINDS.
MONDAY...CHANCE OF RAIN OR SNOW AND MVFR/IFR.
TUESDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
KJB
&&
.MARINE...
100 AM CST
SURFACE HIGH PRESSURE WILL CONTINUE TO RESULT IN GENERALLY LIGHT
WESTERLY FLOW OVER THE LAKE THROUGH THURSDAY. HOWEVER...BY
FRIDAY...AN AREA OF LOW PRESSURE IS EXPECTED TO TRACK FROM THE
SOUTHERN MISSISSIPPI VALLEY EASTWARD OVER THE SOUTHEASTERN CONUS
AS A SURFACE RIDGE OF HIGH PRESSURE BUILDS SOUTHWARD OVER THE
UPPER GREAT LAKES. THIS LOOKS TO RESULT IN A PERIOD OF STRONGER
NORTHERLY WINDS...ESPECIALLY OVER THE SOUTHERN END OF THE
LAKE. THIS COULD RESULT IN THE NEED FOR ANOTHER SMALL CRAFT
ADVISORY FOR THE ILLINOIS AND INDIANA NEAR SHORES.
HOWEVER...THERE ARE UNCERTAINTIES ON WAVE HEIGHTS ALONG THE NEAR
SHORES DUE TO THE RECENT BUILD UP OF ICE. ICE TRENDS WILL NEED TO
BE MONITORED OVER THE NEXT COUPLE DAYS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION...CORRECTED
NWS GOODLAND KS
231 PM MST WED JAN 20 2016
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
WV IMAGERY AND RAP H5/H7 ANALYSIS SHOWS TWO SHORTWAVE TROUGHS
IMPACTING THE CENTRAL ROCKIES AND PLAINS. THE STRONGER CLOSED CENTER
JUST EAST OF OUR CWA OVER NORTH CENTRAL KANSAS AND HAS DEEPENED
THROUGH MIDDAY. THE SECOND IS ENTERING EASTERN COLORADO. BETWEEN
THESE FEATURES THERE IS A SHORTWAVE RIDGE AND REGION OF
DRY/SUBSIDENT AIR APPARENT ON WV IMAGERY. AT THE SURFACE...A SURFACE
TROUGH IS IN PLACE OVER EASTERN COLORADO AND WHERE SKIES HAVE
CLEARED TEMPS HAVE WARMED IN TO THE 40S/50S. OVER OUR CWA (EAST OF
TROUGH AXIS) EXTENSIVE CLOUD COVER HAS SIGNIFICANTLY LIMITED HEATING
AND SEVERAL UPDATES TO HIGH TEMPS WERE WARRANTED EARLIER TODAY.
THIS AFTERNOON-THURSDAY...FOCUS CONTINUES TO BE ON POTENTIAL FOR
SNOW ACROSS OUR CWA. RADAR IS SHOWING SIGNS OF INCREASE IN
REFLECTIVITY IN OUR EASTERN CWA AND HILL CITY HAS STARTED TO REPORT
LIGHT SNOW. THIS CORRELATES WITH OF STRONG VORTICITY NEAR CLOSED LOW
CENTER AND BETTER MID LEVEL MOISTURE IS BEGINNING TO FILL IT. TREND
WILL BE FOR THIS CENTER TO ROTATE NORTH AND EAST TONIGHT BEFORE
SLIDING WELL EAST OF OUR CWA. AN ELEVATED BAROCLINIC ZONE/REGION OF
WEAK FRONTOGENESIS WILL DEVELOP AS THESE SHORTWAVE INTERACT AND PLACE
THE NORTHERN HALF OF OUR CWA IN A FAVORABLE LOCATION FOR POSSIBLE
LIGHT SNOW DEVELOPMENT BY THURSDAY MORNING. THE LIMITING FACTOR WILL
BE MOISTURE ADVECTION AS BOTH SHORTWAVE WILL TEND TO CUT OFF GULF
MOISTURE AND MODELS HAVE GENERALLY LIMITED QPF OVER OUR CWA
ACCORDINGLY. IN THE MEAN TIME...THE DRY/SUBSIDENT REGION BETWEEN
FEATURES MAY LIMIT ANY SNOW DEVELOPMENT IN OUR SOUTH.
I FAVORED THE EASTERN/NORTHEAST PART OF OUR CWA TONIGHT AND
THURSDAY MORNING FOR HIGHEST POPS. SNOW TOTALS SHOULD GENERALLY
RANGE 0.5-1" THOUGH IF THE EASTERN SHORTWAVE WERE TO REMAIN CLOSER
TO OUR CWA WE MAY HAVE A ROW OF COUNTIES RECEIVE AROUND 2" WHEN ALL
IS SAID AND DONE. ALL SNOWFALL SHOULD QUICKLY DISSIPATE/TRANSITION
EASTWARD AS THE RESULTING COMBINED TROUGH SHIFTS EAST AND RIDGING
BUILDS INTO OUR CWA THURSDAY AFTERNOON.
MODELS CONTINUE TO SHOW STRONGER BL WINDS DEVELOPING ON BACK SIDE OF
UPPER LOW AS THE TWO SHORTWAVES MERGE AND POST FRONTAL PRESSURE
GRADIENT INCREASES. LOCATION OF STRONGEST WINDS ACTUALLY CORRELATES
WITH MOST LIKELY LOCATION OF DRY SLOT DEVELOPMENT AND ABOVE
FREEZING TEMPERATURES DURING THE DAY THURSDAY. MIXING MAY BE LIMITED
IN LOCATIONS WITH CLOUD COVER/SNOW AND BL WINDS ARE LESS TO THE
NORTHEAST WHERE SNOWFALL IS MOST LIKELY. SINCE STRONGEST WINDS ARE
UNLIKELY TO BE LOCATED WITH BETTER SNOW CHANCES AND ACCUMULATIONS
ARE LIGHT I DID NOT SEE THE NEED TO KEEP BLOWING SNOW IN THE
FORECAST. AT MOST WE MAY SEE A BRIEF PERIOD OF DRIFTING SNOW AS SNOW
WINDS DOWN BEFORE TEMPS INCREASE TO FREEZING (OR WARMER). ANY
DRIFTING WOULD BE MINOR CONSIDERING AMOUNTS WE ARE DEALING WITH AS
WELL AS PEAK GUSTS IN THE REGION OF BETTER LIGHT SNOW ACCUMULATIONS
20-25 MPH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
THERE ARE A COUPLE OF FORECAST CONCERNS IN THE LONG TERM PERIOD.
FIRST IS THE TEMPERATURE GRADIENT ACROSS THE FORECAST AREA
THROUGH THE END OF THE WEEK AND INTO THE WEEKEND AS COOLER AIR
MOVES EAST AND WARMER DOWNSLOPING CONDITIONS OCCUR OVER THE WEST.
SECOND IS THE POSSIBILITY AND TYPE OF PRECIPITATION LATE SUNDAY
THROUGH EARLY MONDAY MORNING AS THE WARM AND DRY PATTERN
TRANSITIONS BRIEFLY BACK TO A COOLER AND MORE ACTIVE PATTERN AS A
SERIES OF DISTURBANCES MOVES ACROSS THE REGION LATE IN THE WEEKEND
THROUGH EARLY NEXT WEEK.
THE UPPER RIDGE MOVES EAST OVER THE HIGH PLAINS ON THURSDAY NIGHT
THROUGH FRIDAY NIGHT AND CONTINUES OVER THE EASTERN PLAINS STATES
ON SATURDAY. THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE MOVES
INTO THE PLAINS STATES BY FRIDAY...WITH A LEE TROUGH DEEPENING
ALONG THE FRONT RANGE IN RESPONSE TO THE FLATTENING UPPER FLOW AS
AS SEVERAL SHORT WAVE TROUGHS MOVE THROUGH THE UPPER FLOW
SATURDAY NIGHT AHEAD OF THE NEXT MAIN UPPER TROUGH AXIS. THIS WILL
KEEP THE COOLER AIR OVER THE FAR EASTERN SECTIONS OF THE FORECAST
AREA AS THE WESTERN SECTIONS WARM UP. THE THURSDAY NIGHT THROUGH
SATURDAY NIGHT TIME PERIOD WILL STAY DRY AS A RESULT. HOWEVER...THE
TEMPERATURE GRADIENT ACROSS MY FORECAST AREA IS USUALLY MORE
DRAMATIC THAN DEPICTED BY ANY MODEL SOLUTIONS AND HAVE THEREFORE
TRIED TO GO TOWARDS THE WARM END OF GUIDANCE OVER THE WEST AND
TOWARDS THE COOL END OF GUIDANCE OVER THE EAST TO MAKE THE
GRADIENT MORE DRAMATIC. ANY RELUCTANCE OF LOW CLOUD COVER TO
DISSIPATE OVER THE EASTERN SECTIONS...AS HAS BEEN THE CASE OVER
RECENT DAYS...WILL ALSO ACT TO INCREASE THE TEMPERATURE GRADIENT.
A SURFACE LOW CONSOLIDATES OVER THE NORTHERN PANHANDLE REGION ON
SUNDAY...LIFTING INTO MISSOURI BY MONDAY MORNING ALONG THE
FRONTAL BOUNDARY EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN
PLAINS AS THE MAIN UPPER TROUGH AXIS MOVES EAST OF THE ROCKIES BY
SUNDAY AFTERNOON. A DEEPER AND BROADER UPPER TROUGH IS EVENTUALLY
CARVED OUT OVER MUCH OF THE UNITED STATES EAST OF THE ROCKIES BY
MONDAY NIGHT AS ANOTHER RIDGE MOVES INTO PLACE OVER THE WEST
COAST. THIS WILL OPEN THE DOOR TO COLDER AIR DIVING SOUTH INTO THE
PLAINS STATES ON MONDAY. WITH THE TRACK OF THE SURFACE LOW
REMAINING WELL SOUTH OF THE FORECAST AREA AND LITTLE MOISTURE TO
WORK WITH...EXPECT ONLY A SLIGHT CHANCE OF LIGHT RAIN OR SNOW
LATE SUNDAY TRANSITIONING TO ALL SNOW SUNDAY EVENING...WITH
MINIMAL ACCUMULATIONS POSSIBLE MAINLY ACROSS SOUTHERN NEBRASKA AND
EASTERN COLORADO.
THE UPPER WEST COAST RIDGE FLATTENS AND MOVES EAST OVER THE
MOUNTAINOUS WEST BETWEEN SUNDAY AND WEDNESDAY WITH ANOTHER LEE
TROUGH DEEPENING ALONG THE FRONT RANGE. WESTERLY NEAR SURFACE
FLOW WILL PRODUCE DRYING CONDITIONS AND WARMING TEMPERATURES
AGAIN OVER THE FORECAST AREA ON TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1026 AM MST WED JAN 20 2016
BASED ON RECENT TRENDS WITH OBS AND SUPPORTED BY SHORT RANGE
GUIDANCE IFR CIGS/VIS SHOULD IMPROVE TO VFR DURING THE EARLY PART
OF THE TAF PERIOD. A COLD FRONT WILL MOVE THROUGH THE REGION LATE
THIS EVENING WITH WINDS SHIFTING TO THE NORTHWEST AND INCREASING
THROUGH THE NIGHT. STRATUS WILL ONCE AGAIN DEVELOP BEHIND THIS
FRONT LATE TONIGHT AND THURSDAY MORNING...AND THERE COULD BE A FEW
SNOW SHOWERS AROUND THE REGION. THERE IS STILL ENOUGH UNCERTAINTY
IN SNOW COVERAGE I WAS MOST COMFORTABLE LIMITING MENTION TO VCSH
THURSDAY MORNING AT KMCK WHERE BETTER CHANCES ARE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
219 PM MST WED JAN 20 2016
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
WV IMAGERY AND RAP H5/H7 ANALYSIS SHOWS TWO SHORTWAVE TROUGHS
IMPACTING THE CENTRAL ROCKIES AND PLAINS. THE STRONGER CLOSED CENTER
JUST EAST OF OUR CWA OVER NORTH CENTRAL KANSAS AND HAS DEEPENED
THROUGH MIDDAY. THE SECOND IS ENTERING EASTERN COLORADO. BETWEEN
THESE FEATURES THERE IS A SHORTWAVE RIDGE AND REGION OF
DRY/SUBSIDENT AIR APPARENT ON WV IMAGERY. AT THE SURFACE...A SURFACE
TROUGH IS IN PLACE OVER EASTERN COLORADO AND WHERE SKIES HAVE
CLEARED TEMPS HAVE WARMED IN TO THE 40S/50S. OVER OUR CWA (EAST OF
TROUGH AXIS) EXTENSIVE CLOUD COVER HAS SIGNIFICANTLY LIMITED HEATING
AND SEVERAL UPDATES TO HIGH TEMPS WERE WARRANTED EARLIER TODAY.
THIS AFTERNOON-THURSDAY...FOCUS CONTINUES TO BE ON POTENTIAL FOR
SNOW ACROSS OUR CWA. RADAR IS SHOWING SIGNS OF INCREASE IN
REFLECTIVITY IN OUR EASTERN CWA AND HILL CITY HAS STARTED TO REPORT
LIGHT SNOW. THIS CORRELATES WITH OF STRONG VORTICITY NEAR CLOSED LOW
CENTER AND BETTER MID LEVEL MOISTURE IS BEGINNING TO FILL IT. TREND
WILL BE FOR THIS CENTER TO ROTATE NORTH AND EAST TONIGHT BEFORE
SLIDING WELL EAST OF OUR CWA. AN ELEVATED BAROCLINIC ZONE/REGION OF
WEAK FRONTOGENESIS WILL DEVELOP AS THESE SHORTWAVE INTERACT AND PLACE
THE NORTHERN HALF OF OUR CWA IN A FAVORABLE LOCATION FOR POSSIBLE
LIGHT SNOW DEVELOPMENT BY THURSDAY MORNING. THE LIMITING FACTOR WILL
BE MOISTURE ADVECTION AS BOTH SHORTWAVE WILL TEND TO CUT OFF GULF
MOISTURE AND MODELS HAVE GENERALLY LIMITED QPF OVER OUR CWA
ACCORDINGLY. IN THE MEAN TIME...THE DRY/SUBSIDENT REGION BETWEEN
FEATURES MAY LIMIT ANY SNOW DEVELOPMENT IN OUR SOUTH.
I FAVORED THE EASTERN/NORTHEAST PART OF OUR CWA TONIGHT AND
THURSDAY MORNING FOR HIGHEST POPS. SNOW TOTALS SHOULD GENERALLY
RANGE 0.5-1" THOUGH IF THE EASTERN SHORTWAVE WERE TO REMAIN CLOSER
TO OUR CWA WE MAY HAVE A ROW OF COUNTIES RECEIVE AROUND 2" WHEN ALL
IS SAID AND DONE. ALL SNOWFALL SHOULD QUICKLY DISSIPATE/TRANSITION
EASTWARD AND THE RESULTING COMBINED TROUGH SHIFTS EAST AND RIDING
BUILDS INTO OUR CWA THURSDAY.
MODELS CONTINUE TO SHOW STRONGER BL WINDS DEVELOPING ON BACK SIDE OF
UPPER LOW AS THE TWO SHORTWAVES MERGE AND POST FRONTAL PRESSURE
GRADIENT INCREASES. LOCATION OF STRONGEST WINDS ACTUALLY CORRELATES
WITH MOST LIKELY LOCATION OF DRY SLOT DEVELOPMENT AND ABOVE
FREEZING TEMPERATURES DURING THE DAY THURSDAY. MIXING MAY BE LIMITED
IN LOCATIONS WITH CLOUD COVER/SNOW AND BL WINDS ARE LESS TO THE
NORTHEAST WHERE SNOWFALL IS MOST LIKELY. SINCE STRONGEST WINDS ARE
UNLIKELY TO BE LOCATED WITH BETTER SNOW CHANCES AND ACCUMULATIONS
ARE LIGHT I DID NOT SEE THE NEED TO KEEP BLOWING SNOW IN THE
FORECAST. AT MOST WE MAY SEE A BRIEF PERIOD OF DRIFTING SNOW AS SNOW
WINDS DOWN BEFORE TEMPS INCREASE TO FREEZING (OR WARMER). ANY
DRIFTING WOULD BE MINOR AS WELL WITH PEAK GUSTS IN THE REGION OF
BETTER LIGHT SNOW ACCUMULATIONS 20-25 MPH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 132 PM MST WED JAN 20 2016
THERE ARE A COUPLE OF FORECAST CONCERNS IN THE LONG TERM PERIOD.
FIRST IS THE TEMPERATURE GRADIENT ACROSS THE FORECAST AREA
THROUGH THE END OF THE WEEK AND INTO THE WEEKEND AS COOLER AIR
MOVES EAST AND WARMER DOWNSLOPING CONDITIONS OCCUR OVER THE WEST.
SECOND IS THE POSSIBILITY AND TYPE OF PRECIPITATION LATE SUNDAY
THROUGH EARLY MONDAY MORNING AS THE WARM AND DRY PATTERN
TRANSITIONS BRIEFLY BACK TO A COOLER AND MORE ACTIVE PATTERN AS A
SERIES OF DISTURBANCES MOVES ACROSS THE REGION LATE IN THE WEEKEND
THROUGH EARLY NEXT WEEK.
THE UPPER RIDGE MOVES EAST OVER THE HIGH PLAINS ON THURSDAY NIGHT
THROUGH FRIDAY NIGHT AND CONTINUES OVER THE EASTERN PLAINS STATES
ON SATURDAY. THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE MOVES
INTO THE PLAINS STATES BY FRIDAY...WITH A LEE TROUGH DEEPENING
ALONG THE FRONT RANGE IN RESPONSE TO THE FLATTENING UPPER FLOW AS
AS SEVERAL SHORT WAVE TROUGHS MOVE THROUGH THE UPPER FLOW
SATURDAY NIGHT AHEAD OF THE NEXT MAIN UPPER TROUGH AXIS. THIS WILL
KEEP THE COOLER AIR OVER THE FAR EASTERN SECTIONS OF THE FORECAST
AREA AS THE WESTERN SECTIONS WARM UP. THE THURSDAY NIGHT THROUGH
SATURDAY NIGHT TIME PERIOD WILL STAY DRY AS A RESULT. HOWEVER...THE
TEMPERATURE GRADIENT ACROSS MY FORECAST AREA IS USUALLY MORE
DRAMATIC THAN DEPICTED BY ANY MODEL SOLUTIONS AND HAVE THEREFORE
TRIED TO GO TOWARDS THE WARM END OF GUIDANCE OVER THE WEST AND
TOWARDS THE COOL END OF GUIDANCE OVER THE EAST TO MAKE THE
GRADIENT MORE DRAMATIC. ANY RELUCTANCE OF LOW CLOUD COVER TO
DISSIPATE OVER THE EASTERN SECTIONS...AS HAS BEEN THE CASE OVER
RECENT DAYS...WILL ALSO ACT TO INCREASE THE TEMPERATURE GRADIENT.
A SURFACE LOW CONSOLIDATES OVER THE NORTHERN PANHANDLE REGION ON
SUNDAY...LIFTING INTO MISSOURI BY MONDAY MORNING ALONG THE
FRONTAL BOUNDARY EXTENDING FROM THE GREAT LAKES INTO THE SOUTHERN
PLAINS AS THE MAIN UPPER TROUGH AXIS MOVES EAST OF THE ROCKIES BY
SUNDAY AFTERNOON. A DEEPER AND BROADER UPPER TROUGH IS EVENTUALLY
CARVED OUT OVER MUCH OF THE UNITED STATES EAST OF THE ROCKIES BY
MONDAY NIGHT AS ANOTHER RIDGE MOVES INTO PLACE OVER THE WEST
COAST. THIS WILL OPEN THE DOOR TO COLDER AIR DIVING SOUTH INTO THE
PLAINS STATES ON MONDAY. WITH THE TRACK OF THE SURFACE LOW
REMAINING WELL SOUTH OF THE FORECAST AREA AND LITTLE MOISTURE TO
WORK WITH...EXPECT ONLY A SLIGHT CHANCE OF LIGHT RAIN OR SNOW
LATE SUNDAY TRANSITIONING TO ALL SNOW SUNDAY EVENING...WITH
MINIMAL ACCUMULATIONS POSSIBLE MAINLY ACROSS SOUTHERN NEBRASKA AND
EASTERN COLORADO.
THE UPPER WEST COAST RIDGE FLATTENS AND MOVES EAST OVER THE
MOUNTAINOUS WEST BETWEEN SUNDAY AND WEDNESDAY WITH ANOTHER LEE
TROUGH DEEPENING ALONG THE FRONT RANGE. WESTERLY NEAR SURFACE
FLOW WILL PRODUCE DRYING CONDITIONS AND WARMING TEMPERATURES
AGAIN OVER THE FORECAST AREA ON TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1026 AM MST WED JAN 20 2016
BASED ON RECENT TRENDS WITH OBS AND SUPPORTED BY SHORT RANGE
GUIDANCE IFR CIGS/VIS SHOULD IMPROVE TO VFR DURING THE EARLY PART
OF THE TAF PERIOD. A COLD FRONT WILL MOVE THROUGH THE REGION LATE
THIS EVENING WITH WINDS SHIFTING TO THE NORTHWEST AND INCREASING
THROUGH THE NIGHT. STRATUS WILL ONCE AGAIN DEVELOP BEHIND THIS
FRONT LATE TONIGHT AND THURSDAY MORNING...AND THERE COULD BE A FEW
SNOW SHOWERS AROUND THE REGION. THERE IS STILL ENOUGH UNCERTAINTY
IN SNOW COVERAGE I WAS MOST COMFORTABLE LIMITING MENTION TO VCSH
THURSDAY MORNING AT KMCK WHERE BETTER CHANCES ARE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
316 PM EST WED JAN 20 2016
.SYNOPSIS...
A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS
AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY
INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE
REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING
MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT
SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL
SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY
EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE
FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS.
P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT
RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN
RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD
OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND
COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL
MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT
BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES
THIS AFTN BEFORE THICKER CLDNS ARRIVES.
ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD
BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW
TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS
FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH.
HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE
IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE
SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY
EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S.
WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE
LEANED TOWARD THE COOLER MET NUMBERS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE
FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND
DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL
UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW
AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO
BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE
SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF
THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT
BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL
TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH
CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION
OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES.
FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A
TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A
SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY
MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS
THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION
FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND
WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND
EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF
THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE
NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF
THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH
RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN.
FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF
LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF
THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD
FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN
SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE
POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES
OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN
RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT
OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH
FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR
NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN
PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND
LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN.
AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS
CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND
THERMODYNAMIC PROFILES CHANGE.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES
SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE
WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A
GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE
CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE
CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW
FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN
SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND
MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH
DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE
MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S
BY MON.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID TO LATE AFTN
TODAY. HOWEVER...CLOUDS WILL INCREASE AND LOWER QUICKLY FROM WEST
TO EAST AS AN UPPER LEVEL SYSTEM SWINGS THROUGH THE REGION THIS
EVENING. THIS SYSTEM WILL BRING A QUICK ROUND OF LIGHT SNOW TO ALL
TAF SITES FROM ROUGHLY 20/2300Z TO 21/0800Z. CONDITIONS DROP TO
MVFR WITH CIGS AROUND 2500FT AGL AND VISIBILITIES AROUND 3-4SM IN
-SN. LIGHT AND VARIABLE WINDS THIS AFTN WILL SHIFT TO THE NW AFTER
MIDNIGHT TONIGHT INTO THURSDAY MORNING BEHIND THE PASSING SYSTEM.
WINDS EXPECTED TO GUST UP TO 15-20KT ALONG CHES BAY AND THE
ATLANTIC COAST AS STRONGER WINDS MIX DOWN OVER THE WATERS. HIGH
PRESSURE PASSES OVER THE AREA ON THURSDAY. A STRONG WINTER STORM
WILL THEN AFFECT THE REGION LATE THU NIGHT INTO THE WEEKEND.
RAPIDLY DETERIORATING CONDITIONS DUE TO LOW CIG/VIS RESTRICTIONS
SHOULD BE ANTICIPATED BEGINNING FRIDAY AFTN.
&&
.MARINE...
AN ACTIVE WEATHER PATTERN WILL PREVAIL IN THE MARINE AREA FOR THE
NEXT SEVERAL DAYS. A WELL ADVERTISED STORM SYSTEM WILL PRODUCE ROUGH
CONDITIONS BEGINNING FRIDAY NIGHT.
IN THE MEANTIME...A WEAK LOW PRESSURE SYSTEM WILL MOVE THROUGH
OVERNIGHT. BEHIND IT NW WINDS WILL TEMPORARILY INCREASE. A SCA IS IN
EFFECT FOR THE CHESAPEAKE BAY AND CURRITUCK SOUND LATE TONIGHT
THROUGH MID MORNING THURSDAY.
HIGH PRESSURE BUILDS OVER THE WATERS THURSDAY AND THURSDAY NIGHT. A
DEVELOPING STORM SYSTEM OVER THE SOUTHERN STATES WILL EVENTUALLY
DEVELOP A LOW PRESSURE SYSTEM ON THE NORTH CAROLINA COAST. THIS
LOW WILL INTENSIFY FRIDAY EVENING. NE WINDS INCREASE RAPIDLY
AROUND 00Z FRIDAY EVENING. THE LOW MOVES TO OFF THE MD/VA COAST
SATURDAY. STRONG SCA TO GALE FORCE WINDS CAN BE EXPECTED AFTER
MIDNIGHT FRIDAY NIGHT INTO SATURDAY MORNING WITH GUSTS OVER 40
KNOTS EXPECTED IN THE BAY AND COASTAL WATERS. SOLID SCA WINDS
CONTINUES INTO SUNDAY. SEAS IN THE COASTAL WATERS WILL REMAIN 5
FT OR HIGHER THROUGH MONDAY MORNING.
THE PRESSURE PATTERN WEAKENS EARLY NEXT WEEK WITH QUIET MARINE
WEATHER DURING MUCH OF NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORY EXTENDED THROUGH LATE THURSDAY AFTN FOR ALL
MARINE ZONES EXCEPT CURRITUCK SOUND...AND NC COASTAL WATERS DUE
TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN LOWER LOW
WATER. ADDED THE UPPER AND LOWER JAMES RIVER SINCE THE JAMESTOWN
BUOY HAS BEEN MEASURING BLOWOUT TIDES BTWN 1-2 FT BELOW MLLW.
TIDAL ANOMALIES ARE FORECAST TO INCREASE TO 1.5 TO 2.0 FT LATE
FRI INTO SAT...AS LO PRES IMPACTS THE REGION. THE COMBINATION OF
STRONG ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES
REACHING MHHW WILL PUSH COASTAL AREAS OF THE MD/VA EASTERN SHORE
AND SRN CHES BAY TOWARD MINOR FLOODING THRESHOLDS. STRONG NW
WINDS BEHIND THE DEPARTING SYSTEM WILL POTENTIALLY FAVOR MINOR
FLOODING OF THE CHESAPEAKE BAY SIDE OF THE LOWER EASTERN SHORE.
GALE CONDITIONS POSSIBLE LATE FRI NIGHT INTO SAT WITH SEAS
BUILDING TO 5 TO 12 FT COULD RESULT IN BEACH AND GENERAL SHORELINE
EROSION...ESPECIALLY FROM CHES BAY NWD ALONG THE ATLANTIC COAST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH SUNDAY MORNING
FOR MDZ021>023.
NC...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH SUNDAY MORNING
FOR NCZ012.
VA...WINTER STORM WATCH FROM FRIDAY MORNING THROUGH SUNDAY MORNING
FOR VAZ048-060>062-064>069-075>090-092-509>522.
MARINE...LOW WATER ADVISORY UNTIL 3 PM EST THURSDAY FOR ANZ650-652-654-
656.
LOW WATER ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ630>632-634-
637-638.
SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EST THURSDAY FOR
ANZ630>634.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...ALB/ESS
SHORT TERM...ESS
LONG TERM...MAS
AVIATION...BMD/TMG
MARINE...LSA
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
118 PM EST WED JAN 20 2016
.SYNOPSIS...
A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS
AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY
INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE
REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING
MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT
SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL
SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY
EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE
FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS.
P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT
RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN
RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD
OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND
COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL
MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT
BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES
THIS AFTN BEFORE THICKER CLDNS ARRIVES.
ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD
BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW
TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS
FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH.
HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE
IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE
SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY
EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S.
WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE
LEANED TOWARD THE COOLER MET NUMBERS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE
FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND
DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL
UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW
AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO
BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE
SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF
THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT
BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL
TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH
CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION
OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES.
FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A
TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A
SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY
MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS
THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION
FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND
WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND
EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF
THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE
NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF
THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH
RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN.
FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF
LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF
THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD
FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN
SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE
POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES
OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN
RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT
OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH
FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR
NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN
PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND
LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN.
AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS
CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND
THERMODYNAMIC PROFILES CHANGE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES
SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE
WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A
GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE
CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE
CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW
FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN
SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND
MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH
DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE
MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S
BY MON.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID TO LATE AFTN
TODAY. HOWEVER...CLOUDS WILL INCREASE AND LOWER QUICKLY FROM WEST
TO EAST AS AN UPPER LEVEL SYSTEM SWINGS THROUGH THE REGION THIS
EVENING. THIS SYSTEM WILL BRING A QUICK ROUND OF LIGHT SNOW TO ALL
TAF SITES FROM ROUGHLY 20/2300Z TO 21/0800Z. CONDITIONS DROP TO
MVFR WITH CIGS AROUND 2500FT AGL AND VISIBILITIES AROUND 3-4SM IN
-SN. LIGHT AND VARIABLE WINDS THIS AFTN WILL SHIFT TO THE NW AFTER
MIDNIGHT TONIGHT INTO THURSDAY MORNING BEHIND THE PASSING SYSTEM.
WINDS EXPECTED TO GUST UP TO 15-20KT ALONG CHES BAY AND THE
ATLANTIC COAST AS STRONGER WINDS MIX DOWN OVER THE WATERS. HIGH
PRESSURE PASSES OVER THE AREA ON THURSDAY. A STRONG WINTER STORM
WILL THEN AFFECT THE REGION LATE THU NIGHT INTO THE WEEKEND.
RAPIDLY DETERIORATING CONDITIONS DUE TO LOW CIG/VIS RESTRICTIONS
SHOULD BE ANTICIPATED BEGINNING FRIDAY AFTN.
&&
.MARINE...
UPDATE...
SCA FLAGS ISSUED FOR CHES BAY AND CURRITUCK SOUND AFTER MIDNIGHT
TONIGHT INTO MID-THURSDAY MORNING AS NW WINDS INCREASE TO 15-20KT
BEHIND A SHORTWAVE PASSING THROUGH THE REGION THIS EVENING. WINDS
ALSO 15-20KT OVER ALL COASTAL WATERS BUT NOT STRONG ENOUGH TO
SUPPORT 25KT GUST CRITERIA FOR SCA FLAGS.
PREVIOUS DISCUSSION...
HIGH PRESSURE WILL BUILD RIGHT OVER THE WATERS THIS AFTN...THEN
WEAKEN AS AN UPPER LEVEL SYSTEM SLIDES ACROSS THE AREA AND OFF
THE COAST THIS EVENING. WINDS WILL BECOME WSW THIS AFTN THRU
EARLY TONIGHT...THEN BECOME NW AGAIN LATE TONIGHT INTO THU MORNING
BEHIND THE SYSTEM. HIGH PRES BUILDS INTO AND OVER THE AREA DURING
THU.
ATTENTION THEN TURNS TO A POTENT STORM SYSTEM SET TO IMPACT THE
REGION FRI INTO SUN. INCREASINGLY POOR BOATING CONDITIONS
ANTICIPATED BY LATER FRI THRU THE WEEKEND. NNW WINDS VEER AROUND
TO THE NNE EARLY FRI...THEN INCREASE FRI AFTN/EVENING...AS LOW
PRESSURE LIFTS ALONG THE SE COAST AND HIGH PRESSURE BUILDS INTO
CANADA. THE SFC LOW LIFTS OFF THE MID ATLANTIC COAST FRI NIGHT
INTO SAT...LIFTING AWAY FROM THE COAST SAT THRU SUN. STRONG SCA
WINDS EXPECTED LATER FRI INTO SUN...WITH GALE FORCE WINDS POSSIBLE
OVR THE COASTAL WATERS AND CHES BAY LATE FRI NIGHT INTO SUN...AS
FLOW TURNS FROM NE TO NNW. SEAS WILL ALSO BUILD QUICKLY REACHING
AS HIGH AS 8-12 FT SAT.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORY EXTENDED THROUGH LATE THURSDAY AFTN FOR ALL
MARINE ZONES EXCEPT CURRITUCK SOUND...AND NC COASTAL WATERS DUE
TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN LOWER LOW
WATER. ADDED THE UPPER AND LOWER JAMES RIVER SINCE THE JAMESTOWN
BUOY HAS BEEN MEASURING BLOWOUT TIDES BTWN 1-2 FT BELOW MLLW.
TIDAL ANOMALIES ARE FORECAST TO INCREASE TO 1.5 TO 2.0 FT LATE
FRI INTO SAT...AS LO PRES IMPACTS THE REGION. THE COMBINATION OF
STRONG ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES
REACHING MHHW WILL PUSH COASTAL AREAS OF THE MD/VA EASTERN SHORE
AND SRN CHES BAY TOWARD MINOR FLOODING THRESHOLDS. STRONG NW
WINDS BEHIND THE DEPARTING SYSTEM WILL POTENTIALLY FAVOR MINOR
FLOODING OF THE CHESAPEAKE BAY SIDE OF THE LOWER EASTERN SHORE.
GALE CONDITIONS POSSIBLE LATE FRI NIGHT INTO SAT WITH SEAS
BUILDING TO 5 TO 12 FT COULD RESULT IN BEACH AND GENERAL SHORELINE
EROSION...ESPECIALLY FROM CHES BAY NWD ALONG THE ATLANTIC COAST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...LOW WATER ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ630>632-634-
637-638.
SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EST THURSDAY FOR
ANZ630>634.
LOW WATER ADVISORY UNTIL 3 PM EST THURSDAY FOR ANZ650-652-654-
656.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...ALB/ESS
SHORT TERM...ESS
LONG TERM...MAS
AVIATION...BMD/TMG
MARINE...BMD/TMG
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1232 PM EST WED JAN 20 2016
.SYNOPSIS...
A WEAK UPPER LEVEL SYSTEM PASSES ACROSS THE AREA LATE THIS
AFTERNOON THROUGH THIS EVENING. HIGH PRESSURE RETURNS THURSDAY
INTO THURSDAY NIGHT. A STRONG LOW PRESSURE SYSTEM WILL AFFECT THE
REGION FRIDAY INTO SUNDAY. HIGH PRESSURE RETURNS FOR EARLY NEXT
WEEK.
&&
.NEAR TERM /THROUGH THURSDAY/...
FIRST ORDER OF BUSINESS IS ELONGATED/WK TROUGH SFC-ALOFT CROSSING
MTNS ATTM. HI PRES INVOF FA LT THIS MRNG CONTG TO WEAKEN AS THAT
SYS APPROACHES THROUGH MID AFTN. LO LVLS RMN QUITE DRY...MDL
SOUNDINGS INDICATE SLO SATURATION ABV 5-7KFT INTO LT AFTN/EARLY
EVE. LATEST RUC HAS PD OF WK UVM ACCOMPANYING MOISTURE THROUGH THE
FA...21Z/20-00Z/21 WRN PORTION...23Z/20-04Z/21 CNTRL-E PORTIONS.
P-TYPE WILL NOT BE AN ISSUE...INSTEAD ITS QPF. GIVEN ONLY SLGT
RECOVERY TO DEWPTS AND LIMITED SATURATION BLO 5KFT...XPCG SN
RATIOS TO BE 15-20%. MENTIONING LGT SN...AND GIVEN ONLY BRIEF PD
OF ACTUAL PCPN OCCURRING...LGT ACCUMS (1/2" OR LESS) XPCTD. GROUND
COLD SO SHOULD NOT BE DIFFICULT TO HAVE ROADS COATED QUICKLY. WILL
MONITOR PCPN TRENDS EARLY/MID AFTN FOR PSBL NEED FOR AN (IMPACT
BASED) ADVISORY THIS EVE. TEMPS REBOUND INTO THE L30S MOST PLACES
THIS AFTN BEFORE THICKER CLDNS ARRIVES.
ONCE THIS TROUGH EXITS LT THIS EVE/OVRNGT...SFC PRES WILL BUILD
BACK INTO THE AREA. THE CLOUDS WILL CLEAR QUICKLY AND SHOULD ALLOW
TEMPERATURES TO DROP INTO THE LOW TO MID 20S. THE MOS GUIDANCE IS
FAIRLY WELL CLUSTERED TONIGHT SO DID NOT DEVIATE MUCH.
HIGH PRESSURE WILL REMAIN IN PLACE ON THURSDAY WITH SOME INCREASE
IN HIGH CLOUDS LATE IN THE DAY AS THE STORM SYSTEM OVER THE
SOUTHERN PLAINS BEGINS TO ORGANIZE. BUT WITH A MOSTLY SUNNY DAY
EXPECTED...TEMPERATURES SHOULD WARM INTO THE MID TO UPPER 30S.
WITH THE MAV NUMBERS HAVING BEEN RUNNING ON THE WARM SIDE HAVE
LEANED TOWARD THE COOLER MET NUMBERS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
THE MODELS CONTINUE TO ADVERTISE A MAJOR STORM SYSTEM FOR THE
FRIDAY INTO THE WEEKEND TIME PERIOD. HOWEVER...THE TRACK AND
DETAILS OF WHERE THE COLD AND WARM AIR RESIDE ARE STILL
UNCERTAIN...WHICH LEADS TO SOME DIFFICULT IN NAILING DOWN SNOW
AREAS AND AMOUNTS. AS OF THE 00Z MODEL RUNS...THE GFS CONTINUES TO
BE FASTER THAN THE ECMWF AND NAM MODELS...BUT ALL MODELS ARE
SLOWER THAN LAST NIGHTS RUNS. SO HAVE AGAIN SLOWED THE ONSET OF
THE PCPN...BUT NOT NEARLY AS MUCH AS THE NAM/ECMWF SOLUTIONS. BUT
BY FRIDAY NIGHT...THE MODELS ALL AGREE THAT THE SFC LOW WILL
TRANSFER FROM THE OHIO VALLEY TO NEAR THE NORTHEASTERN NORTH
CAROLINA COAST. BUT THEY DIFFER BY ABOUT 100 MILES ON THE LOCATION
OF THE LOW WHICH IMPACTS HOW FAR NORTH AND WEST THE WARM AIR GOES.
FOR NOW...THE GFS HAS BEEN THE MODEL OF CHOICE SO HAVE GONE A
TOUCH FURTHER NORTH AND WEST WITH THE WARM AIR. THIS SETS UP A
SITUATION WHERE MUCH OF THE AREA BEGINS AS SNOW FRIDAY
MORNING...AS THE PCPN SPREADS ACROSS THE AREA FROM SW TO NE. AS
THE WARM AIR BEGINS TO LIFT NORTHWARD ALOFT WILL SEE A TRANSITION
FROM SNOW THROUGH A WINTRY MIX AND THEN TO ALL RAIN IN THE SE AND
WILL WATCH THAT TRANSITION LINE HEAD NE FRIDAY AFTERNOON AND
EVENING. EVENTUALLY...THIS SHOULD HAVE THE TRANSITIONS LINE NW OF
THE I-85 CORRIDOR/WEST OF RICHMOND AND THROUGH MUCH OF THE
NORTHERN NECK AND LOWER MD EASTERN SHORE COUNTIES. THE TREND OF
THE MODELS OVER THE LAST DAY OR SO HAS BEEN TO BE COLDER WITH EACH
RUN SO WHERE THIS TRANSITION LINE ENDS UP IS STILL UNCERTAIN.
FOR PCPN AMOUNTS...THE CURRENT THINKING IS THAT 1 - 2 INCHES OF
LIQUID PCPN ARE POSSIBLE THROUGH FRIDAY NIGHT WITH THE HEAVIEST OF
THAT IN THE EASTERN HALF OF THE REGION WHERE MUCH OF THIS WOULD
FALL AS RAIN. BUT TO THE NWRN PART OF THE AREA WHERE THE PCPN
SHOULD BE EITHER FROZEN OR A MIX...SUBSTANTIAL AMOUNTS ARE
POSSIBLE. INITIAL GUIDANCE FROM WPC HAS AMOUNTS OF 12 - 15 INCHES
OF SNOW OVER THE MOST NW PART OF THE CWA WITH 8 - 10 INCHES IN
RICHMOND VICINITY. CURRENT THINKING IS THOSE AMOUNTS...WHILE NOT
OUT OF THE REALM OF POSSIBILITY MAY BE A LITTLE HIGH THROUGH
FRIDAY NIGHT AS THE HEAVIER PCPN SHOULD BE FURTHER EAST. SO FOR
NOW HAVE LEANED MORE TOWARD 8 - 12 IN THE NORTHERN AND WESTERN
PORTIONS OF THE AREA AND 4 - 8 ACROSS THE RICHMOND METRO AREAS AND
LESS SOUTH AND EAST AS THE WARM AIR CHANGES THE PCPN TO RAIN.
AGAIN...THERE IS STILL MUCH UNCERTAIN AND AS THE EVENT GETS
CLOSER...THE TOTALS COULD EASILY CHANGE AS THE STORM TRACK AND
THERMODYNAMIC PROFILES CHANGE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
LONG TERM PERIOD STARTS OFF SAT WITH THE AFOREMENTIONED LO PRES
SYSTM STRENGTHENING OFF THE MID ATLC CST. MAIN FORECAST CHANGE
WITH THIS UPDATE WAS TO INCREASE POPS BOTH SAT AND SAT NGT WITH A
GOOD DEAL OF PCPN LIKELY ON THE BACK SIDE OF THE LO. PTYPE
CONTINUES TO APPEAR TO BE SNOW OVER THE PIEDMONT...RAIN NR THE
CST...AND A RAIN/SNOW MIX IN BETWEEN. A LOT WILL DEPEND ON HOW
FAST LO-LEVEL THICKNESSES CRASH BEHIND THE DEPARTING LO. PCPN
SHOULD END FM W TO E SAT NGT. DRY CONDS EXPECTED THEN FOR SUN AND
MON WITH SFC HI PRES OVER THE AREA. TEMPS WILL RISE A LITTLE EACH
DAY...WITH HIGHS RANGING FM THE MID 30S OVER THE PIEDMONT TO THE
MID/UPR 40S NR THE CST SAT...INCREASING TO THE MID 40S TO LWR 50S
BY MON.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE THRU AT LEAST MID AFTN TODAY.
BUT...CLOUDS WILL INCREASE AND LWR QUICKLY...AS AN UPR LEVEL
SYSTEM MOVES TOWARDS THE REGION. THAT UPR LEVEL SYSTEM WILL THEN
CROSS THE REGION LATE THIS AFTN INTO EARLY TNGT...BRINGING A CHC
FOR SOME LIGHT SNOW. MAINLY VFR CIGS ARE STILL EXPECTED AS THE
LIGHT SNOW MOVES THRU. HOWEVER...MVFR CIGS WILL BE POSSIBLE...ESPLY
AT RIC/SBY/PHF. NW WINDS EARLY TODAY...WILL SHIFT TO THE W THEN SW
LATE THIS MORNG INTO EARLY TNGT...THEN BACK AGAIN TO THE NW OVRNGT
TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES WILL PASS OVER THE
AREA ON THU. A STRONG WINTER STORM WILL THEN AFFECT THE REGION
LATE THU NGT INTO THE WEEKEND.
&&
.MARINE...
SCA CONDITIONS WILL CONTINUE UNTIL 10 AM THIS MORNG OVR ALL WTRS
EXCEPT THE RIVERS...DUE TO RATHER STRONG NW WINDS STILL OCCURRING
AS HI PRES BLDS JUST TO THE W OF THE WTRS. THE HI WILL BLD RIGHT
OVR THE WTRS EARLY THIS AFTN...THEN WEAKEN AS AN UPR LEVEL SYSTEM
SLIDES ACRS THE AREA AND OFF THE CST LATE THIS AFTN INTO EARLY
TNGT. WINDS WILL BECOME WSW THIS AFTN THRU EARLY TNGT...THEN BECOME
NW AGAIN LATE TNGT INTO THU MORNG BEHIND THE SYSTEM. HI PRES BLDS
INTO AND OVR THE AREA DURING THU.
ATTENTION THEN TURNS TO A POTENT STORM SYSTEM SET TO IMPACT THE
REGION FRI INTO SUN. INCREASINGLY POOR BOATING CONDITIONS ANTICIPATED
BY LATER FRI THRU THE WEEKEND. NNW WINDS VEER AROUND TO THE NNE
EARLY FRI...THEN INCREASE FRI AFTN/EVENG...AS LO PRES LIFTS ALONG
THE SE CST AND HI PRES BLDS INTO CANADA. THE SFC LOW LIFTS OFF THE
MID-ATLC CST FRI NIGHT INTO SAT...LIFTING AWAY FM THE CST SAT THRU
SUN. STRONG SCA WINDS EXPECTED LATER FRI INTO SUN...WITH GALE
FORCE WINDS POSSIBLE OVR THE CSTL WTRS AND CHES BAY LATE FRI NGT
INTO SUN...AS FLO TURNS FM NE TO NNW. SEAS WILL ALSO BLD QUICKLY
REACHING AS HIGH AS 8-12+ FT SAT.
&&
.TIDES/COASTAL FLOODING...
LOW WATER ADVISORY EXTENDED THROUGH LATE THURSDAY AFTN FOR ALL
MARINE ZONES EXCEPT CURRITUCK SOUND...AND NC COASTAL WATERS DUE
TO WATER LEVELS EXPECTED TO REACH 1 TO 1.5 BELOW MEAN LOWER LOW
WATER. ADDED THE UPPER AND LOWER JAMES RIVER SINCE THE JAMESTOWN
BUOY HAS BEEN MEASURING BLOWOUT TIDES BTWN 1-2 FT BELOW MLLW.
TIDAL ANOMALIES ARE FORECAST TO INCREASE TO 1.5 TO 2.0 FT LATE
FRI INTO SAT...AS LO PRES IMPACTS THE REGION. THE COMBINATION OF
STRONG ONSHORE FLOW IN ADVANCE OF THE SYSTEM AND ASTRO TIDES
REACHING MHHW WILL PUSH COASTAL AREAS OF THE MD/VA EASTERN SHORE
AND SRN CHES BAY TOWARD MINOR FLOODING THRESHOLDS. STRONG NW
WINDS BEHIND THE DEPARTING SYSTEM WILL POTENTIALLY FAVOR MINOR
FLOODING OF THE CHESAPEAKE BAY SIDE OF THE LOWER EASTERN SHORE.
GALE CONDITIONS POSSIBLE LATE FRI NIGHT INTO SAT WITH SEAS
BUILDING TO 5 TO 12 FT COULD RESULT IN BEACH AND GENERAL SHORELINE
EROSION...ESPECIALLY FROM CHES BAY NWD ALONG THE ATLANTIC COAST.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...LOW WATER ADVISORY UNTIL 7 PM EST THURSDAY FOR ANZ630>632-634-
637-638.
SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EST THURSDAY FOR
ANZ630>634.
LOW WATER ADVISORY UNTIL 3 PM EST THURSDAY FOR ANZ650-652-654-
656.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...ALB/ESS
SHORT TERM...ESS
LONG TERM...MAS
AVIATION...TMG
MARINE...TMG
TIDES/COASTAL FLOODING...BMD
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
150 PM EST WED JAN 20 2016
LATEST UPDATE...
HYDRO
.SYNOPSIS...
ISSUED AT 315 AM EST WED JAN 20 2016
AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY.
TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL
MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT
CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS
WEEKEND OR EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1233 PM EST WED JAN 20 2016
THE MESO-SCALE HEAVY SNOW BAND AS MOVES SOMEWHAT TO THE SOUTH AND
IS NOW MOSTLY BETWEEN MUSKEGON AND GRAND HAVEN. DUAL POLE RADAR
SHOWS STORM TOTALS BETWEEN 3 TO 4 INCHES HAS FALLEN IN THAT AREA.
SINCE THE LATEST MODEL DATA SUGGESTS THE BAND WILL NOT START
MOVING ON SHORE UNTIL AROUND 3 PM... I EXTENDED THE ADVIOSRY TILL
4 PM.
UPDATE ISSUED AT 1102 AM EST WED JAN 20 2016
I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW.
THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING
REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E
DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW
AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE
STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E
DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION.
REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE
ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES
EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES
WITH FLURRIES.
UPDATE ISSUED AT 551 AM EST WED JAN 20 2016
CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY
GIVEN CURRENT TRENDS:
A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS
SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF
SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6
HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN
TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST
WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE
CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND
GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT
THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE
CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE
EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR
LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD
EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO
WHITEHALL.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES
ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN
INCH OF SNOW.
THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG
COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME
ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND
INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER
TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS
PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN
EFFECT UNTIL 18Z THIS AFTN.
TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW
LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI
TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH
THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A
CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT
IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN
NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS
COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF
SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK.
THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S.
UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST
TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL
AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE
GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT
LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST
NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN
TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE
FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN
INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO
MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN
A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT
THIS EARLY STAGE.
THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING
THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW.
RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF
THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A
CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS
SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE.
FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING
INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE
REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY
TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING
RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR
TRENDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1243 PM EST WED JAN 20 2016
LIGHT SNOW WILL GRADUALLY DIMINISH AT MKG THIS AFTERNOON. SLIGHTLY
WARMER AND MORE MOIST AIR WILL MOVE ACROSS LOWER MICHIGAN TONIGHT
LEADING TO MVFR CIGS.
&&
.MARINE...
ISSUED AT 315 AM EST WED JAN 20 2016
WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND
FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF
THE NEARSHORE WATERS.
&&
.HYDROLOGY...
ISSUED AT 150 PM EST WED JAN 20 2016
ICE JAMS HAVE FORMED IN SPOTS ALONG SEVERAL RIVERS. A GENERAL RISE
IN RIVER LEVELS WITH OCCASIONAL DOWNWARD FLUCTUATIONS HAS BEEN
OCCURRING IN SPOTS SUCH AS IONIA... EAGLE... SMYRNA... AND
SCOTTVILLE. IONIA HAS SUPASSED BANKFULL THIS AFTERNOON AND THE
OTHER THREE ARE CONTENDERS THE NEXT FEW DAYS.
WITH BELOW-FREEZING WEATHER CONTINUING THROUGH THE REMAINDER OF
THE WEEK... LITTLE CHANGE IN THE ICE JAMS IS EXPECTED... AND
RIVER LEVELS SH0ULD REMAIN ELEVATED UPSTREAM OF THE JAMS.
SIGNIFICANT FLOODING IS NOT AN IMMEDIATE CONCERN. NEVERTHELESS...
ICE JAMS CAN CAUSE RELATIVELY RAPID CHANGES IN RIVER LEVELS
UPSTREAM AND DOWNSTREAM OF THE JAM WITH LITTLE ADVANCE NOTICE.
CONTINUE TO MONITOR FUTURE FORECASTS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ050-
056-064.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...HOVING
AVIATION...04
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1246 PM EST WED JAN 20 2016
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 315 AM EST WED JAN 20 2016
AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY.
TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL
MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT
CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS
WEEKEND OR EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1233 PM EST WED JAN 20 2016
THE MESO-SCALE HEAVY SNOW BAND AS MOVES SOMEWHAT TO THE SOUTH AND
IS NOW MOSTLY BETWEEN MUSKEGON AND GRAND HAVEN. DUAL POLE RADAR
SHOWS STORM TOTALS BETWEEN 3 TO 4 INCHES HAS FALLEN IN THAT AREA.
SINCE THE LATEST MODEL DATA SUGGESTS THE BAND WILL NOT START
MOVING ON SHORE UNTIL AROUND 3 PM... I EXTENDED THE ADVIOSRY TILL
4 PM.
UPDATE ISSUED AT 1102 AM EST WED JAN 20 2016
I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW.
THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING
REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E
DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW
AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE
STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E
DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION.
REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE
ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES
EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES
WITH FLURRIES.
UPDATE ISSUED AT 551 AM EST WED JAN 20 2016
CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY
GIVEN CURRENT TRENDS:
A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS
SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF
SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6
HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN
TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST
WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE
CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND
GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT
THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE
CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE
EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR
LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD
EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO
WHITEHALL.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES
ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN
INCH OF SNOW.
THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG
COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME
ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND
INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER
TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS
PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN
EFFECT UNTIL 18Z THIS AFTN.
TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW
LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI
TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH
THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A
CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT
IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN
NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS
COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF
SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK.
THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S.
UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST
TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL
AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE
GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT
LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST
NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN
TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE
FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN
INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO
MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN
A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT
THIS EARLY STAGE.
THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING
THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW.
RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF
THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A
CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS
SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE.
FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING
INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE
REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY
TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING
RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR
TRENDS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1243 PM EST WED JAN 20 2016
LIGHT SNOW WILL GRADUALLY DIMINISH AT MKG THIS AFTERNOON. SLIGHTLY
WARMER AND MORE MOIST AIR WILL MOVE ACROSS LOWER MICHIGAN TONIGHT
LEADING TO MVFR CIGS.
&&
.MARINE...
ISSUED AT 315 AM EST WED JAN 20 2016
WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND
FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF
THE NEARSHORE WATERS.
&&
.HYDROLOGY...
ISSUED AT 324 PM EST TUE JAN 19 2016
WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING...
HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER
AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY
IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO
WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE
REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ050-
056-064.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...HOVING
AVIATION...04
HYDROLOGY...WDM
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1237 PM EST WED JAN 20 2016
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 315 AM EST WED JAN 20 2016
AN UPPER LEVEL DISTURBANCE WILL BRING MORE LIGHT SNOW TODAY.
TEMPERATURES WILL REMAIN SEASONABLY COLD TODAY BEFORE A GRADUAL
MODERATING TREND OF TEMPERATURES OCCURS LATE THIS WEEK. THE NEXT
CHANCE FOR ACCUMULATING SNOW WILL NOT COME UNTIL VERY LATE THIS
WEEKEND OR EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1233 PM EST WED JAN 20 2016
THE MESO-SCALE HEAVY SNOW BAND AS MOVES SOMEWHAT TO THE SOUTH AND
IS NOW MOSTLY BETWEEN MUSKEGON AND GRAND HAVEN. DUAL POLE RADAR
SHOWS STORM TOTALS BETWEEN 3 TO 4 INCHES HAS FALLEN IN THAT AREA.
SINCE THE LATEST MODEL DATA SUGGESTS THE BAND WILL NOT START
MOVING ON SHORE UNTIL AROUND 3 PM... I EXTENDED THE ADVIOSRY TILL
4 PM.
UPDATE ISSUED AT 1102 AM EST WED JAN 20 2016
I PLAN TO KEEP OUR WINTER WEATHER ADVISORY GOING AS IS FOR NOW.
THE LATEST MODEL DATA SHOWS THE AREA OF STRONG MESO-SCALE FORCING
REMAINING LARGELY STATIONARY TILL 18Z. THE AREA THAT THETA-E
DECREASE WITH HEIGHT BETWEEN 1000 MB AND 925 MB IS RATHER NARROW
AND DOES NOT MOVE UNTIL AFTER 18Z. THE 88D RADAR SHOWS THE
STRONGEST RADAR RETURNS OVER THE AREA WITH THE GREATEST THETA-E
DECREASING WITH HEIGHT AND IN TURN THE GREATEST VERTICAL MOTION.
REPORTS SO FAR SHOW 1 TO 2 INCHES HAS FALLEN... I COULD SEE
ANOTHER INCH OR SO FALL THERE BEFORE THE BAND WEAKENS AND MOVES
EAST MID TO LATE AFTERNOON. ELSEWHERE EXPECT MOSTLY CLOUDY SKIES
WITH FLURRIES.
UPDATE ISSUED AT 551 AM EST WED JAN 20 2016
CURRENTLY CONSIDERING A WINTER STORM WARNING FOR MUSKEGON COUNTY
GIVEN CURRENT TRENDS:
A DOMINANT LAKE EFFECT BAND IS ONGOING AT THIS TIME ACROSS
SOUTHERN MUSKEGON COUNTY. HRRR SFC WIND FIELDS AND SIM REF
SUGGESTS THIS BAND MAY MIGRATE EAST SOMEWHAT OVER THE NEXT 3 TO 6
HOURS BUT LARGELY BE IMPACTING THE SAME AREAS...NAMELY GRAND HAVEN
TO WHITEHALL. LAND BASED OBS ARE SHOWING SSE WINDS ALONG THE COAST
WHILE WSW WINDS ARE COMING OFF THE LAKE. THIS WILL CONTINUE
CREATING LOW LEVEL CONVERGENCE AND MAY KEEP THIS MATURE BAND
GOING FOR SEVERAL HOURS. MOISTURE DEPTH STAYS AT OR ABOVE 10K FT
THROUGH 18Z. HRRR GUIDANCE SUGGESTS IT MAY NOT MOVE OUT OF THE
CURRENT AREA UNTIL 18Z OR SO. SNOWFALL RATES OF 1"-2" PER HOUR ARE
EXPECTED WITHIN THIS BAND WITH VISIBILITIES TO A QUARTER MILE OR
LESS AND POOR TRAVEL. ADDITIONAL SNOWFALL OF 3"-6" OR MORE COULD
EASILY BE ACHIEVED IN THE HARDEST HIT AREAS...FROM GRAND HAVEN TO
WHITEHALL.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
LIGHT SNOW IS ANTICIPATED TODAY AS AN UPPER LEVEL SYSTEM MOVES
ACROSS LWR MI. MOST OF OUR FCST AREA WILL ONLY RECEIVE LESS THAN AN
INCH OF SNOW.
THE EXCEPTION TO THIS IS FROM ALLEGAN COUNTY NORTHWARD TO MKG
COUNTY WHERE SW FLOW LAKE ENHANCEMENT WILL OCCUR ALONG WITH SOME
ENHANCED LIFT. SNOW SHOULD GRADUALLY INCREASE IN COVERAGE AND
INTENSITY DURING THE EARLY TO MID MORNING HOURS THERE AS THE UPPER
TROF AXIS APPROACHES. 2 TO 4 INCHES OF SNOW IS ANTICIPATED ACROSS
PORTIONS OF THOSE COUNTIES WHERE THE WINTER WX ADVISORY REMAINS IN
EFFECT UNTIL 18Z THIS AFTN.
TRANQUIL WX IS ANTICIPATED TONIGHT THROUGH FRIDAY WITH JUST A FEW
LINGERING FLURRIES OR VERY LIGHT SNOW SHOWERS NEAR LAKE MI
TONIGHT. TEMPS WILL UNDERGO A GRADUAL MODERATING TREND AND REACH
THE MIDDLE 20S THURSDAY AND AROUND 30 DEGREES ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM EST WED JAN 20 2016
OUR MAIN FOCUS FOR THE EXTENDED FORECAST CONTINUES TO CENTER ON A
CHANCE FOR LIGHT SNOW PRIMARILY FROM SUNDAY NIGHT INTO MONDAY NIGHT
IN ASSOCIATION WITH A WEAK SURFACE LOW. THIS SNOW WILL BE WETTER IN
NATURE COMPARED TO RECENT EVENTS. SOME LAKE EFFECT SNOW SHOWERS
COULD FOLLOW FOR TUESDAY. RIGHT NOW IT SEEMS THAT A FEW INCHES OF
SNOW COULD FALL FOR THE EARLY PORTION OF NEXT WEEK.
THE SYSTEM OF INTEREST WILL NOT EVEN MAKE IT TO THE WESTERN U.S.
UNTIL THE WEEKEND...LEAVING SOME ROOM FOR ERROR IN THE FORECAST
TRACK UNTIL IT GETS BETTER SAMPLED BY THE UPPER AIR NETWORK AS WELL
AS AMDAR. NEVERTHELESS...DECENT AGREEMENT IS SHOWN BY THE
GFS/ECMWF/GEM IN BRINGING THE SUBTROPICAL JET INTO THE LOWER GREAT
LAKES REGION BY THE END OF THE WEEKEND. THE ECMWF IS THE FURTHEST
NORTH WITH THE JET AND HENCE THE SFC LOW THAT IS GENERATED IS SHOWN
TO TRACK ACROSS NORTHERN LOWER MI ON MONDAY. THE GFS AND GEM ARE
FURTHER SOUTH. EVEN SO...EITHER OF THESE SOLUTIONS SUPPORTS AN
INCREASED RISK FOR LIGHT SNOW TO IMPACT LOWER MI MAINLY MONDAY INTO
MONDAY NIGHT. OUR BLEND OF MEDIUM RANGE GUIDANCE SUPPORTS LESS THAN
A 50/50 SHOT AT THIS SNOW...BUT I THINK IT MAY BE UNDERDONE EVEN AT
THIS EARLY STAGE.
THE TRACK OF THE LOW (WEAK AS IT MAY BE) AND THE CORRESPONDING
THERMAL PROFILES WILL DETERMINE IF ANY RAIN MIXES IN WITH THE SNOW.
RIGHT NOW I AM NOT SEEING MUCH SUPPORT FOR LIQUID PRECIP...THOUGH IF
THE ECMWF TRENDS FURTHER NORTH THEN WE MAY HAVE TO INTRODUCE A
CHANCE FOR A RAIN/SNOW MIX ON MONDAY. ACCUMULATION WISE...THIS
SYSTEM COULD SUPPORT 1"-3" OF SNOW FOR OUR AREA IF TRENDS CONTINUE.
FOR TUESDAY...MODELS SUPPORT CYCLONIC FLOW AND H850 TEMPS FALLING
INTO THE -10C TO -14C RANGE ALONG WITH POTENTIALLY DEEP MOISTURE
REMAINING IN PLACE ON THE BACK SIDE OF THE LOW. THIS IS ESPECIALLY
TRUE WITH THE GFS SOLUTION. THUS THERE APPEARS TO BE AN INCREASING
RISK FOR LAKE EFFECT SNOW SHOWERS BY THAT TIME. WE WILL MONITOR
TRENDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1156 PM EST TUE JAN 19 2016
SNOW WILL BE ON THE INCREASE OVERNIGHT WITH WIDESPREAD IFR
CONDITIONS DEVELOPING BY 12Z WEDNESDAY. EXPECT IFR AND SOME AREAS
OF LIFR WEDNESDAY MORNING WITH CONDITIONS SLOWLY IMPROVING TO
MVFR DURING THE AFTERNOON. WINDS WILL WEST SOUTHWEST AOB 10
KNOTS.
&&
.MARINE...
ISSUED AT 315 AM EST WED JAN 20 2016
WINDS/WAVE ACTION WILL REMAIN QUITE MINIMAL THROUGH FRIDAY AND
FAIRLY EXTENSIVE ICE BUILDUP CONTINUES TO DEVELOP OVER PORTIONS OF
THE NEARSHORE WATERS.
&&
.HYDROLOGY...
ISSUED AT 324 PM EST TUE JAN 19 2016
WIDESPREAD ICE FORMATION ON AREA RIVERS... WITH SOME ICE JAMMING...
HAS CAUSED RIVER LEVEL FLUCTUATIONS AT MANY SITES. THE GRAND RIVER
AT ROBINSON TOWNSHIP HAS DROPPED BELOW FLOOD STAGE AND THE ADVISORY
IS CANCELED. A FEW RIVERS ARE APPROACHING BANKFULL THIS AFTERNOON SO
WILL HAVE TO BE CLOSELY MONITORED. TEMPERATURES BELOW FREEZING THE
REST OF THIS WEEK SHOULD INCREASE ICE COVERAGE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ050-
056-064.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...HOVING
AVIATION...OSTUNO
HYDROLOGY...WDM
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
357 PM CST WED JAN 20 2016
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
BIGGEST FORECAST ISSUE WILL BE SNOW AMOUNTS FOR TONIGHT.
SNOW HAS BEGUN A BIT EARLIER THAN ANTICIPATED IN OUR SOUTH IN
ADVANCE OF THE LONG-AWAITED APPROACHING WAVE WITHIN PROGRESSIVE
FLOW. BACKED UP THE START TIME OF THE ADVISORY FOR OUR KANSAS
COUNTIES TO INCLUDE THIS AFTERNOON. ALSO INCREASED SNOW AMOUNTS A
BIT IN OUR SOUTH...WHICH REQUIRED THE ADDITION OF A FEW COUNTIES ON
THE WESTERN EDGE OF THE WINTER WEATHER ADVISORY...TO INCLUDE
WEBSTER...SMITH...AND OSBORNE COUNTIES. EXPECTING A RATHER TYPICAL
13:1 RATIO FOR LIQUID TO SNOW.
FORECAST IS LARGELY ON TRACK FROM THE PREVIOUS FORECAST TONIGHT WITH
MINOR CHANGES MADE IN GENERAL. SNOWFALL MAY NOT FOLLOW A SMOOTH
TRANSITION FROM HEAVIER TO LIGHTER AMOUNTS FROM SOUTH TO NORTH...AS
WE COULD GET A FEW CONVECTIVE BANDS TO MOVE THROUGH...AS INDICATED
BY SHORT TERM MODELS SUCH AS HRRR AND RAP.
ANOTHER ISSUE MAY COME LATE THURSDAY AFTERNOON WHEN WE COULD LOSE
SATURATION IN THE DENDRITIC GROWTH ZONE BEFORE ALL OF THE LIGHT
LINGERING PRECIPITATION EXITS. IF THIS OCCURS...THEN WE COULD GET
SOME FREEZING DRIZZLE DEVELOP LATE AFTERNOON THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 356 PM CST WED JAN 20 2016
HAZARDOUS WX POTENTIAL: NOTHING SIGNIFICANT FORESEEN AT THIS TIME.
ALOFT: SOME TEMPORARY PROGRESSION OF THE LONGWAVES WILL OCCUR AS THE
PERSISTENT E PAC TROF MOVES ONSHORE SAT AND INTO THE CNTRL USA SUN-
MON. THIS TROF WILL SHIFT INTO THE ERN USA BEYOND MON. THEN IT`S
BACK TO THE PATTERN DOMINATING THE PAST 2 WEEKS...WITH THE E PAC
TROF/WRN N AMERICA RIDGE REDEVELOPING.
SURFACE: CANADIAN HIGH PRES WILL CREST OVER THE FCST AREA THU NIGHT
INTO FRI. SAT THE FCST AREA WILL BE IN THE WARM SECTOR OF A CLIPPER
TRACKING ACROSS SRN CANADA. LEE CYCLOGENESIS WILL ENSUE SAT NIGHT
WITH THE APPROACH OF THE UPR TROF. A PAC COLD FRONT WILL SLIP THRU
SUN AS THIS LOW CONTS TO ORGANIZE OVER OK/KS. WPC HAS THIS LOW OVER
CNTRL MO AT 12Z/MON WHICH IS CLOSE TO THE 06Z/12Z GFS AND THE
00Z/12Z GEM. INTERESTINGLY...THE 12Z GFS ENSEMBLE MEAN IS ON THE
SLOW END OF THE GUIDANCE SPREAD (OVER ERN KS/OK) WHILE THE 00Z/12Z
EC AND THE 00Z ENSEMBLE MEAN ARE ON THE FASTER END OVER IA.
HIGH PRES OVERTAKES THE REGION MON AND SINKS INTO THE SRN PLAINS TUE-
WED. DOWNSLOPE-WARMED AIR SHOULD FLOOD THE PLAINS AS A COUPLE
CLIPPERS TRACK N OF THE FCST AREA.
SOME DAILY DETAILS...
THU NIGHT: A LITTLE LIGHT SNOW OR FRZG DRZL COULD LINGER INTO THE
EVENING HRS MAINLY HWY 81. CONFIDENCE IS LOW. OTHERWISE CLOUDY. KEPT
LOW TEMPS A LITTLE ABOVE NORMAL.
FRI: LOTS OF UNCERTAINTY ON DEPARTURE OF THE LOW CLOUDS...BUT THE
THERMAL TROF SHIFTING E IS A GOOD SIGN. HIGH TEMPS ARE LOW
CONFIDENCE. THE SNOW THAT FALLS TONIGHT WILL BE A PLAYER.
SAT: INCREASING/DESCENDING MULTI-LAYERED CLOUDS...ESPECIALLY IN THE
AFTERNOON. IT`S LOOKING VERY MILD...BUT AGAIN SNOW COVER A
MITIGATING FACTOR.
SUN: THE FCST IS CURRENTLY DRY...BUT IT`S POSSIBLE SOME LIGHT PRECIP
COULD BREAK OUT IN THE AFTERNOON. NOT EXACTLY SURE ON PRECIP TYPE AS
WETBULB COOLING COULD BE AN ISSUE IN THE INITIALLY DRY AIR BELOW 10K
FT.
THE LAST 2 RUNS OF THE OP MODELS ARE ALL OVER THE PLACE WITH VERY
LIGHT QPF AND AMTS SUN NIGHT. THE 12Z GFS ENSEMBLE DOES HAVE A 30%
PROBABILITY FOR .10" IN 24 HRS OVER S-CNTRL NEB. THE 12Z EC ENSEMBLE
IS SIMILAR. SO THERE COULD BE A TOUCH OF LIGHT WINTRY PRECIP.
MON: A LITTLE LIGHT SNOW COULD LINGER INTO THE MORNING. COLD SECTOR
WITH THERMAL TROF PASSING THRU. COLDER AND PROBABLY M/CLOUDY.
THE-WED: DRY AND QUIET WITH TEMPS MODERATING.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1158 AM CST WED JAN 20 2016
CEILINGS AND VISIBILITY WILL CONTINUE TO BE QUITE VARIABLE AT THE
BEGINNING OF THE FORECAST AS AN AREA OF STRATUS PUSHES NORTH. LOW
CONFIDENCE FOR THE TIMING OF THE RETURN OF STRATUS/SNOW AS ANOTHER
WINTER SYSTEM COMES INTO PLAY. A TEMPORARY WINDOW OF MVFR
CONDITIONS IS EXPECTED THIS LATE AFTERNOON/EARLY EVENING BEFORE
CONDITIONS DETIORATE ONCE AGAIN.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR NEZ085>087.
KS...WINTER WEATHER ADVISORY UNTIL NOON CST THURSDAY FOR KSZ006-007-
018-019.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...HALBLAUB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1153 AM CST WED JAN 20 2016
.AVIATION.../18Z TAF CYCLE/
LIFR/IFR AND MVFR CONDITIONS PERSIST ACROSS THE REGION AS OF 1745Z
WITH LOW STRATUS CEILINGS REMAINING INTACT UNDERNEATH A STRONG
INVERSION. KAUS IS ON THE EDGE OF THE STRATUS DECK BUT CONTINUED
MVFR CIGS WILL CONTINUE TO MOVE IN FROM THE SOUTH THROUGH THE
AFTERNOON. KSAT/KSSF/KDRT ARE NOT EXPECTED TO IMPROVE MUCH FURTHER
THAN CURRENT CONDITIONS THROUGH THE AFTERNOON AS WELL. NAM BUFR
SOUNDINGS ALONG WITH LAMP GUIDANCE AND HRRR OUTPUT ALL SUPPORT
WORSENING FLIGHT CATEGORIES THIS EVENING STARTING NEAR OR AFTER 04Z.
EXPECT IFR/LIFR CONDITIONS AT ALL SITES WITH SOME POSSIBLE/LIKELY
POCKETS OF VLIFR WITH VISIBILITY RESTRICTIONS OCCURRING DOWN TO 1/2
SM AT TIMES DUE TO LOW CLOUDS/FOG. LOW LEVEL SATURATION MAY EVEN BE
GREAT ENOUGH FOR -DZ TO OCCUR AS WELL. CIGS/VIS WILL REMAIN LOW
THROUGH THURSDAY MORNING TILL 15-18Z BEFORE A CLEARING FRONT MOVES
THROUGH. CONDITIONS SHOULD RAPIDLY IMPROVE WITH THE PASSAGE OF THE
FRONT THURSDAY AFTERNOON /21Z/ TO VFR. SURFACE WINDS WILL BE WEAK
THIS AFTN AND OVERNIGHT AT 10 KT OR LESS FROM THE NORTH AND BECOMING
EAST TO SOUTHEAST AHEAD OF THE FRONT. WINDS WILL REALLY INCREASE
ALONG AND BEHIND THE FRONT TO THE WNW AT 15-20 WITH GUSTS TO 30 KT
THURSDAY AFTN. WILL PLACE MORE FOCUS ON WINDS IN SUBSEQUENT TAF
ISSUANCES.
&&
.PREV DISCUSSION... /ISSUED 1043 AM CST WED JAN 20 2016/
UPDATE...
THE COLD FRONT HAS MOVED SOUTH OF OUR CWA AND IN ITS WAKE LEFT
CLOUDY SKIES OVER SOUTH CENTRAL TEXAS. SURFACE WIND ARE LIGHT FROM
THE NORTH. THIS COMBINATION IS KEEPING TEMPERATURES DOWN AND WE
HAVE LOWERED THE HIGHS FOR TODAY. THE REST OF THE FORECAST LOOKS
TO BE IN GOOD SHAPE AND HAVE ONLY ADJUSTED HOURLY GRIDS TO ACCOUNT
FOR OBSERVATIONAL TRENDS.
PREV DISCUSSION... /ISSUED 427 AM CST WED JAN 20 2016/
SHORT TERM (TODAY THROUGH THURSDAY)...
THE LEADING EDGE OF A WEAK COLD FRONT EXTENDING FROM A SURFACE
LOW PRESSURE SYSTEM OVER SW ARKANSAS HAS ENTERED THE I-35 CORRIDOR
AND WILL CONTINUE TO PUSH TOWARDS THE GULF COAST OVER THE NEXT FEW
HOURS. ALTHOUGH THIS HAS RESULTED IN A NORTHERLY WIND SHIFT...COLD
AIR ADVECTION AT H850-925 IS WEAK AS THE TEMPERATURE GRADIENT IS
BECOMING NEARLY PARALLEL TO THE WIND. SHOWERS ASSOCIATED WITH THE
FRONT AND A WEAK SHORTWAVE BRIEFLY FORMED OVER WILLIAMSON COUNTY
AND EAST TOWARDS COLLEGE STATION AND ARE ATTEMPTING TO REFORM IN
FAYETTE COUNTY EAST OF LA GRANGE. HOWEVER...THE SURFACE POTENTIAL
TEMPERATURE AND ASSOCIATED DENSITY GRADIENT CONTINUES TO WEAKEN
WHICH SHOULD ALLOW FOR ONLY VERY ISOLATED SHOWERS. PATCHY FOG MAY
DEVELOP AHEAD OF THE FRONT IN THE COASTAL PLAINS OVER THE NEXT FEW
HOURS AND IN THE RIO GRANDE PLAINS THROUGH MID-MORNING WHERE THE
BOUNDARY WILL BE MOST DIFFUSE AND EVENTUALLY BECOME STATIONARY.
MODELS ARE GENERALLY IN GOOD AGREEMENT THAT THE FRONT WILL STALL
ALONG THE RIO GRANDE PLAINS INTO SOUTH TEXAS AND THE UPPER GULF
COAST. SW-NE ORIENTED ISENTROPIC ASCENT WILL SET UP OVER SOUTH
CENTRAL TEXAS TODAY TO CAUSE MOSTLY CLOUDY TO OVERCAST SKIES THAT
WILL LIMIT DAYTIME HEATING...THOUGH LOW LEVEL WARM AIR ADVECTION
SHOULD ALLOW HIGHS TO REACH THE MID TO UPPER 60S OVER THE SOUTHERN
ZONES...WHILE STRUGGLING TO REACH 60 DEGREES OVER OUR NORTHERN
ZONES. THIS WEAKLY DEFINED WARM FRONTAL BOUNDARY WILL PROGRESS TO
THE NORTHEAST WEDNESDAY EVENING AS ANOTHER SURFACE LOW DEVELOPS
OVER NORTH TEXAS IN RESPONSE TO A DIGGING AND INTENSIFYING UPPER
LEVEL TROUGH. THIS WILL KEEP THE REGION IN THE WARM SECTOR OF THE
SURFACE LOW AND ALLOW FOR MOSTLY CLOUDY SKIES AND POSSIBLY SOME
PATCHY ADVECTION FOG THAT WILL KEEP LOWS IN THE 40S AND 50S.
THE SURFACE LOW AND UPPER LEVEL TROUGH IN THE EURO CONTINUES TO
TRACK FURTHER SW THAN THE GFS...WHICH DEPICTS A DEEPER SYSTEM
FURTHER TO THE NE AND KEEPS MOST PRECIP OUT OF OUR AREA. EXTENDED
HI-RES MODEL RUNS AND THE NAM ARE CLOSER TO THE GFS...AND ALL
MODELS TAKE A COLD FRONT THROUGH THE REGION BY 18Z THURSDAY...SO
HAVE CONTINUED TO KEEP PRECIP CHANCES LOW AND CONFINED TO OUR
NE COUNTIES. MOST MODELS SHOW THERE IS A SMALL AMOUNT OF SURFACE
BASED INSTABILITY...SO ISOLATED THUNDERSTORMS WOULD BE POSSIBLE
SHOULD THE TRACK OF THE SYSTEM SIMULATED BY THE EURO VERIFY.
HOWEVER...ELEVATED FIRE WEATHER CONDITIONS IN THE RIO GRANDE
PLAINS ARE A GREATER CONCERN ON THURSDAY AFTERNOON AS MIN RH
VALUES IN THE LOWER 20S AND WINDS SUSTAINED TO 25 KNOTS AND
GUSTING ABOVE 30 KNOTS PERSIST BEHIND THE FRONT. THE HIGH
TEMPERATURE FORECAST...AND ASSOCIATED RH FORECAST...IS FAIRLY
TRICKY ON THURSDAY AS STRONG COLD AIR ADVECTION WILL BE GOING
AGAINST THE EFFECTS OF DAYTIME RADIATIONAL HEATING AND DOWNSLOPING
WINDS. IT CURRENTLY LOOKS LIKE THE COLD AIR ADVECTION WILL WIN OUT
OVER OUR NORTHERN ZONES WHERE HIGHS WILL BE IN THE LOWER TO MID
60S WHILE THE LATTER EFFECTS MAY WIN OUT OVER OUR SOUTHERN ZONES
AND RIO GRANDE PLAINS WHERE HIGHS WILL BE IN THE LOWER 70S.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
STRONG 15-20 KNOT WIND GUSTS WILL CONTINUE THURSDAY NIGHT INTO
FRIDAY AS THE REGION REMAINS ON THE BACKSIDE OF A DEEPENING
CYCLONE OVER THE LOWER MISSISSIPPI VALLEY. THIS STRONGER N-NW FLOW
WILL KEEP HIGHS IN THE LOWER 50S OVER OUR NORTHERN AND EASTERN
ZONES...WHILE REMAINING IN THE LOWER 60S OVER THE RIO GRANDE
PLAINS WHERE THESE EFFECTS WILL BE WEAKER. CALM WINDS AND HIGH
PRESSURE OVERNIGHT FRIDAY INTO SATURDAY WILL ALLOW FOR LOWS IN
THE UPPER 20S IN THE HILL COUNTRY WITH A LIGHT FREEZE FOR MOST
AREAS ALONG AND NORTH OF HIGHWAY 90/INTERSTATE 10. SOUTHERLY WINDS
RETURN ON SATURDAY WITH WARMER THAN NORMAL TEMPERATURES IN THE
UPPER 60S AND LOWER 70S RETURNING ON SUNDAY AS UPPER LEVEL RIDGING
TAKES PLACE AHEAD OF OUR NEXT COLD FRONT THAT MOVES THROUGH ON
MONDAY. LOW MOISTURE LEVELS AND WEAK DYNAMIC FORCING WITH THIS
FRONT MAKES SHOWERS UNLIKELY ON MONDAY...WITH SLIGHTLY COOLER
THAN NORMAL TEMPERATURES AND DRY AIR MOVING IN FOR TUESDAY BEHIND
THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 52 66 39 53 32 / 20 20 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 51 67 37 53 30 / 20 20 0 0 0
NEW BRAUNFELS MUNI AIRPORT 52 69 38 56 31 / 10 20 0 0 0
BURNET MUNI AIRPORT 49 62 35 52 30 / 10 20 0 0 0
DEL RIO INTL AIRPORT 46 69 37 62 34 / - 0 0 0 0
GEORGETOWN MUNI AIRPORT 50 63 37 51 29 / 20 20 0 0 0
HONDO MUNI AIRPORT 49 70 37 60 30 / - 10 0 0 0
SAN MARCOS MUNI AIRPORT 52 67 38 55 31 / 10 20 0 0 0
LA GRANGE - FAYETTE REGIONAL 56 68 39 54 32 / 20 30 - 0 0
SAN ANTONIO INTL AIRPORT 53 70 39 58 33 / 10 10 0 0 0
STINSON MUNI AIRPORT 53 71 39 59 33 / 10 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...ALLEN
SYNOPTIC/GRIDS...05
AREA FORECAST DISCUSSION
NWS SEATTLE WA
258 PM PST WED JAN 20 2016
.SYNOPSIS...A SLOW MOVING FRONTAL SYSTEM WILL BRING RAIN TO WESTERN
WASHINGTON TONIGHT THROUGH FRIDAY MORNING. THE FRONT WILL MOVE EAST
FRIDAY AFTERNOON WITH RAIN CHANGING TO SCATTERED SHOWERS. AN UPPER
LEVEL LOW OVER OREGON WILL BRUSH THE AREA WITH A LITTLE RAIN ON
SATURDAY. AN UPPER LEVEL RIDGE JUST OFFSHORE WILL BRING DRIER
WEATHER SUNDAY AND MONDAY BUT A FEW SHOWERS MAY STILL BE AROUND.
ANOTHER FRONTAL SYSTEM SHOULD REACH THE AREA MONDAY NIGHT OR TUESDAY.
&&
.SHORT TERM...HIGH CLOUDS FROM AN APPROACHING WET FRONTAL SYSTEM
HAVE MOVED OVER W WA THIS AFTERNOON. RAIN IS NOT FAR BEHIND AS RADAR
IS PICKING UP A BAND OF RAIN TO THE SW HEADED TOWARD THE S WA COAST.
THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THE ADVANCING RAIN...
BRINGING IT TO THE CENTRAL COAST AROUND 01Z/5 PM AND TO PUGET SOUND
AROUND 04Z/8 PM.
THE WARM FRONT FROM THIS SYSTEM WILL BRING STRONG WARM ADVECTION
WITH 40-60 KT S-SW WINDS ALOFT FROM 925MB-850MB TO W WA LATER
TONIGHT AND THURSDAY. THIS STRONG S-SW FLOW WILL CONTINUE THURSDAY
NIGHT AS THE SLOW MOVING COLD FRONT APPROACHES. THIS WILL PRODUCE
HEAVY RAIN OVER THE OLYMPICS AND N CASCADES TONIGHT THROUGH THURSDAY
NIGHT. THE SYSTEM WILL WEAKEN FRIDAY MORNING AS THE COLD FRONT MOVES
INLAND.
TOTAL PRECIP OVER THE AREA TONIGHT THROUGH FRIDAY MORNING
WILL BE AROUND 3-6 INCHES OVER THE OLYMPICS AND N CASCADES WITH 0.50-
1.00 OVER THE INTERIOR LOWLANDS. SNOW LEVELS WILL RISE TO NEARLY
7500 FEET BY MIDDAY THURSDAY.
WEAK AND COOL EASTERLY FLOW THROUGH THE CASCADE PASSES SHOULD ALLOW
SEVERAL INCHES OF LIGHT SNOW TO FALL TONIGHT INTO THURSDAY
MORNING...BUT THE STRONG WARMING ALOFT WILL PROBABLY OVERWHELM THE
COOL EAST LOW LEVEL FLOW FOR A CHANGE OVER TO RAIN BEFORE MIDDAY
THURSDAY.
WINDY CONDITIONS WILL DEVELOP OVER MAINLY THE COAST AND N INTERIOR
TONIGHT AND THURSDAY AS THE SYSTEM MOVES OVER THE AREA.
THE COLD FRONT WILL FINALLY BE PUSHED INLAND FRIDAY MORNING ALLOWING
THE RAIN TO TAPER OFF WITH A CHANGE TO SHOWERS IN THE AFTERNOON. A
WEAK UPPER LEVEL RIDGE WILL MOVE OVER THE AREA FRIDAY AFTERNOON FOR
A LITTLE DRYING.
THE LAST COUPLE OF MODEL RUNS HAVE CHANGED FOR SATURDAY. THE LATEST
SOLUTIONS NOW FORM A CLOSED LOW W OF THE N CA COAST ON FRIDAY...THEN
SWING IT NE TO ABOUT THE CENTRAL OREGON COAST SATURDAY MORNING.
INCREASING S FLOW ALOFT AHEAD OF THE LOW NOW SPREADS LIGHT RAIN
NORTHWARD ACROSS W WA SATURDAY MORNING. THE 18Z GFS IS EVEN A LITTLE
FASTER THAN THE 12Z GFS SO LIGHT RAIN MIGHT EVEN MAKE IT UP TO PUGET
SOUND A LITTLE BEFORE SUNRISE. RAIN WILL DIMINISH SATURDAY EVENING
AS THE SYSTEM MOVES E. KAM
.LONG TERM...MODEL SOLUTIONS ARE STILL EVOLVING FROM RUN-TO-RUN IN
THE EXTENDED PERIOD. AN UPPER LEVEL RIDGE JUST OFFSHORE SATURDAY
EVENING WILL EVENTUALLY MOVE OVER W WA MONDAY MORNING. THE 12Z GFS
WAS DRIER DURING THIS PERIOD...BUT NOW THE 18Z RUN HAS SHIFTED BACK
TO A PREVIOUS SOLUTION WHERE A SHORTWAVE TROUGH PUSHES THROUGH THE
RIDGE THEN BRINGS SOME SHOWERS TO THE AREA. FOR NOW...WITH LOW
CONFIDENCE IN THE MODEL SOLUTIONS I WILL KEEP A BROADBRUSH CHANCE OF
SHOWERS SUNDAY AND MONDAY.
MODELS HAVE BEEN BRINGING ANOTHER FRONTAL SYSTEM TO THE AREA EARLY
NEXT WEEK. EARLIER RUNS HAD IT ON MONDAY WHILE THE 18Z GFS HOLDS OFF
UNTIL MONDAY NIGHT AND TUESDAY. ANOTHER FRONTAL SYSTEM MAY ARRIVE
LATE WEDNESDAY. KAM
&&
.AVIATION...SOUTHWESTERLY FLOW ALOFT WILL CONTINUE TONIGHT AND
THURSDAY AS A FRONT STALLS NEAR THE COAST. SURFACE GRADIENTS WILL
BECOME INCREASINGLY SOUTHEASTERLY. THE AIR MASS IS STABLE WITH
INCREASING MOISTURE ALL LEVELS. RAIN WILL BEGIN ON THE COAST AROUND
01Z AND SPREAD INLAND BY 04Z OR SO.
CONDITIONS ARE GOOD VFR OVER MOST OF THE AREA EXCEPT FOR A PATCH
OF MVFR CEILINGS AROUND THE STRAIT OF JUAN DE FUCA. CEILINGS WILL
LOWER TONIGHT AS THE FRONT APPROACHES AND BY THE TIME RAIN BEGINS
THEY WILL BE 3-5K FT. SEVERAL HOURS OF MVFR CEILINGS ARE LIKELY
LATE TONIGHT AND THURSDAY MORNING.
KSEA...DISCUSSION ABOVE APPLIES. SOUTHEAST WIND 5-10 KT WILL
BECOME MORE EASTERLY TONIGHT...THEN SOUTHEAST 10-15 KT AFTER 12Z
THURSDAY. CHB
&&
.MARINE...A STRONG FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND THEN SLOWLY MOVE INLAND TONIGHT AND THURSDAY. GALE
WARNINGS ARE IN EFFECT FOR THE COAST..THE CENTRAL AND EASTERN
STRAIT...AND THE NORTHERN INLAND WATERS. SMALL CRAFT ADVISORIES
ARE IN EFFECT FOR THE REMAINING WATERS.
WINDS WILL EASE THURSDAY NIGHT AND ARE LIKELY TO REMAIN BELOW 20
KT FRIDAY AND SATURDAY. ANOTHER FRONT MAY APPROACH THE COAST
SUNDAY. CHB
&&
.HYDROLOGY...ANOTHER 3 TO 6 INCHES OF PRECIPITATION WILL FALL OVER
THE OLYMPICS AND NORTH CASCADES TONIGHT THROUGH THURSDAY
NIGHT...WITH THE SNOW LEVEL RISING TO 6500 TO 7500 FT. THIS WILL
PUSH THE SKOKOMISH RIVER BACK ABOVE FLOOD STAGE AGAIN PROBABLY
SOMETIME THURSDAY MORNING. THE ONLY REAL QUESTION IS WHETHER OR NOT
IT WILL REACH ITS MAJOR FLOOD STAGE. THE FLOOD WATCH WILL REMAIN IN
EFFECT.
OTHER WESTERN WASHINGTON RIVERS FLOWING OFF THE OLYMPICS AND THE
NORTH CASCADES WILL ALSO RISE SIGNIFICANTLY. HOWEVER NORTHWEST RIVER
FORECAST CENTER GUIDANCE SHOWS MOST OF THESE RIVERS...THE SATSOP...
ELWHA...DUNGENESS...SKAGIT...AND STILLAGUAMISH...CRESTING AT MOST
WITH AROUND 70 PERCENT OF THE DISCHARGE NEEDED TO REACH FLOOD STAGE.
SO THE THREAT ON THESE RIVERS LOOKS PRETTY LOW. THE GUIDANCE FOR THE
NOOKSACK SHOWS IT GETTING CLOSEST TO FLOOD STAGE...THE SOUTH FORK
NOOKSACK SPECIFICALLY...BUT STILL LESS THAN 80 PERCENT OF THE
DISCHARGE CORRESPONDING TO FLOOD STAGE.
WITH FLOODING NOT EXPECTED ON ANY RIVERS OTHER THAN THE SKOKOMISH...
THE FLOOD POTENTIAL OUTLOOK WILL BE ALLOWED TO EXPIRE THIS
AFTERNOON. OTHERWISE...RIVER FLOODING IS NOT EXPECTED THE NEXT 7
DAYS. KAM
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WATCH FROM THIS EVENING THROUGH LATE FRIDAY NIGHT FOR HOOD
CANAL AREA-LOWER CHEHALIS VALLEY AREA-OLYMPICS.
PZ...SMALL CRAFT ADVISORY COAST UNTIL 4 PM PST THIS AFTERNOON.
GALE WARNING COAST...CENTRAL AND E STRAIT AND NORTH INLAND
WATERS FROM 4 PM THIS AFTERNOON TO 7 PM PST THURSDAY.
SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 7 PM PST THURSDAY FOR
GRAYS HARBOR BAR.
SMALL CRAFT ADVISORY UNTIL 4 PM PST THURSDAY FOR PUGET SOUND
AND HOOD CANAL-WEST ENTRANCE U.S. WATERS STRAIT OF JUAN DE FUCA.
SMALL CRAFT ADVISORY UNTIL 7 PM PST THURSDAY FOR ADMIRALTY INLET.
&&
$$
WWW.WEATHER.GOV/SEATTLE
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS PORTLAND OR
257 PM PST WED JAN 20 2016
.SYNOPSIS...A WARM FRONT WILL MOVE ONTO THE COAST LATE THIS
AFTERNOON AND INLAND TONIGHT...AND SNOW LEVELS WILL RISE WELL ABOVE
THE CASCADE PASSES. THE TRAILING COLD FRONT WILL MOVE INLAND THURSDAY
NIGHT AND FRIDAY. A LOW WILL APPROACH FROM THE SOUTHWEST FRIDAY NIGHT
AND SATURDAY FOR MORE RAIN AND CASCADE SNOW. SNOW LEVELS WILL LOWER
BACK DOWN TO NEAR THE CASCADE PASSES OVER THE
WEEKEND. THE PROGRESSIVE WEATHER PATTERN WILL CONTINUE PERIODS OF
RAIN AND CASCADE SNOW INTO NEXT WEEK.
&&
.SHORT TERM...RAIN SHOWERS HAS ENDED TO THE NORTH...BUT THE NEXT BAND
OF RAIN ASSOCIATED WITH A WARM FRONT IS JUST BEGINNING TO REACH THE
CENTRAL OREGON COAST. A LARGE HIGH CLOUD SHIELD IS MAKING IT
DIFFICULT TO SEE ON SATELLITE IMAGERY WHERE THE ACTUAL FRONT IS THIS
AFTERNOON. THE OFFSHORE BUOYS SHOW SE WINDAND DECREASING PRESSURE
SUGGESTING THE FRONT IS STILL QUITE A WAYS OFFSHORE. THERE HAS BEEN A
SMALL AREA OF LIGHTNING STRIKES AROUND 42N 130 W THAT MAY BE
ASSOCIATED WITH A FRONTAL BOUNDARY OR A LOW CENTER...BUT IT IS HARD
TO CURRENTLY TELL.
THE TALE END OF THIS WARM FRONT WILL BRUSH OVER THE REGION LATE THIS
AFTERNOON THROUGH LATE TONIGHT. RAIN WILL MOSTLY BE NORTH OF
SALEM...AND ACROSS THE HIGHER TERRAIN...WITH AROUND 0.5 INCH OF RAIN
FOR FOR THE NORTHERN CASCADES AND NORTHERN COAST RANGE...AND 0.05 TO
0.15 INCH FOR THE INTERIOR LOW LANDS NORTH OF SALEM. EXPECT VERY
LITTLE MEASURABLE RAIN...LESS THAN 0.05 INCH FOR NON-COASTAL AREAS
SOUTH OF SALEM. SNOW LEVELS WILL RAPIDLY RISE THIS EVENING WITH THE
PASSAGE OF THE WARM FRONT AND BE AROUND 7000 FEET LATE TONIGHT. THE
HIGHER VALLEYS IN THE SOUTH WASHINGTON CASCADES WILL HAVE A SLIGHT
CHANCE FOR FREEZING RAIN TONIGHT AND EARLY THURSDAY.
A BUILDING UPPER LEVEL RIDGE OVER THE PACIFIC NW WILL SLOW THE
PROGRESS OF THE COLD FRONT WHICH IS CURRENTLY BETWEEN 130W AND
140W...AND THE FRONT SHOULD STALL JUST OFF OF THE OREGON AND
WASHINGTON COAST THURSDAY. THE COAST WILL LIKELY SEE CONTINUOUS RAIN
BETWEEN THE WARM AND COLD FRONT...BUT MOST INTERIOR AREAS WILL HAVE
A BREAK IN THE RAIN LATE THURSDAY MORNING THROUGH EARLY
FRIDAY....BEFORE THE COLD FRONT MOVE INLAND THURSDAY NIGHT AND FRIDAY
MORNING.
THE FRONT WILL SPLIT OFFSHORE BEFORE IT PUSHES INLAND SENDING THE
HEAVIEST RAINFALL SOUTH OF OREGON...BUT STILL EXPECT A FEW HOURS OF
HEAVY RAIN WITH THE FRONT PASSAGE EARLY FRIDAY MORNING FOR THE COAST
AND COAST RANGE AND MID MORNING TO EARLY AFTERNOON EAST OF THE COAST
RANGE.SNOW LEVELS WILL REMAIN HIGH...ABOVE 7000 FEET. THE COAST AND
COAST RANGE WILL SEE THE MOST RAIN WHERE 0.75 TO 1.25 INCHES OF RAIN
IS EXPECTED THURSDAY EVENING THROUGH FRIDAY MORNING. OTHER AREAS CAN
EXPECT 0.35 TO 0.70 INCHES OF RAIN.
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL SHORT WAVE DEEPENING SOUTH
OF THE ALEUTIAN ISLANDS NEAR 46N 161W. THIS TROUGH WILL SPLIT FROM
THE PARENT UPPER LEVEL TROUGH AS IT MOVES SW ACROSS THE PACIFIC ON
THURSDAY AND FORM A CUT OFF LOW OFFSHORE OF NORTHERN CALIFORNIA
FRIDAY AFTERNOON. THE LOW WILL THEN SEND A WARM FRONT ACROSS NW
OREGON AND SW WASHINGTON FRIDAY NIGHT AND SATURDAY AS THE LOW MOVES
INLAND NEAR THE OREGON/CALIFORNIA BORDER...FOR MORE RAIN AND CASCADE
SNOW. SNOW LEVELS WILL BE AROUND 4500 FEET. TJ
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY. LITTLE CHANGE
TO THE FORECAST AS MODELS REMAIN IN REASONABLY GOOD AGREEMENT
THROUGH THE PERIOD. UPPER TROUGH SLIDES EAST OF THE CASCADES BY LATE
SATURDAY NIGHT WITH RESIDUAL SHOWERS TAPERING OFF AS SHORTWAVE
RIDGING BUILDS OVER THE REGION IN BETWEEN SYSTEMS. MODELS SUGGEST
THE NEXT DISTURBANCE MAY SPLIT OFFSHORE AS IT APPROACHES OVERNIGHT
SUNDAY...PERHAPS BRINGING SOME LIGHT RAIN AT TIMES...PARTICULARLY IN
SW WASHINGTON...BUT IN LIMITED AMOUNTS. MONDAY MAY BE DRY AS UPPER
LEVEL RIDGE AXIS MOVES OVER THE AREA...BUT THE NEXT FRONT WILL
ARRIVE TUESDAY FOR ANOTHER ROUND OF PRECIPITATION. THIS WILL BE IN
THE FORM OF RAIN FOR MOST LOCATIONS AS SNOW LEVELS WILL RISE ABOVE
6000 FEET BY LATE MONDAY BEFORE THE BULK OF THE MOISTURE ARRIVES.
&&
.AVIATION...A WARM FRONT TO LIFT NORTH THROUGH THE REGION LATER
THIS AFTERNOON AND EVENING. THIS WILL BRING INCREASING LIGHT RAIN
AND LOWERING CIGS...ALTHOUGH CONDITIONS SHOULD REMAIN MOSTLY VFR
WITH CIG HEIGHTS AT 4 TO 5 KFT. LIGHT RAIN TO CONTINUE
OVERNIGHT...MAINLY FOR THE COAST AND NORTHERN INTERIOR. CIGS IN
THESE AREAS MAY DROP DOWN TO AROUND 3 KFT BETWEEN 06Z AND 12Z THU.
INLAND AREAS FROM ROUGHLY KSLE SOUTH EXPECTED TO BE MOSTLY DRY
OVERNIGHT AND REMAIN VFR.
HAVE WIND SHEAR CONCERNS AFTER 12Z FOR KTTD AND KPDX AS SURFACE
FLOW WILL BE EASTERLY FROM THE GORGE WHILE FLOW ALOFT WILL
INCREASE FRONT THE SOUTH.
KPDX AND APPROACHES...LIGHT RAIN BEGINS AND CIGS LOWER TO AROUND 5
KFT THIS EVENING AS WARM FRONT MOVES THROUGH THE REGION. LIGHT
RAIN WILL LIKELY CONTINUE MUCH OF THE NIGHT...WITH CIGS LOWERING
FURTHER TO AROUND 3 TO 4 KFT. EXPECT LITTLE CHANGE THROUGH THE DAY
THU. EAST FLOW WILL INCREASE AFTER 09Z THU AND BRING LLWS
CONCERNS FROM ABOUT 12Z THEREAFTER. PYLE
&&
.MARINE...STRONG OCCLUDING LOW PRES NEAR 50N/145W THIS AFTERNOON.
THIS SYSTEM WILL BRING A WARM FRONT THROUGH THE WATERS LATER THIS
AFTERNOON AND THIS EVENING. GUSTY SOUTHERLY WINDS TO INCREASE THIS
EVENING AS WELL...WITH GUSTS 40 TO 45 KT EXPECTED OVER THE OUTER
WATERS WHERE A GALE WARNING IS NOW IN EFFECT. THE PRES GRADIENT TO
REMAIN FAIRLY OFFSHORE...SO THINK WINDS WILL NOT BE QUITE AS
STRONG OVER THE NEAR SHORE WATERS. THINK A SMALL CRAFT ADVISORY
WILL BE SUFFICIENT. THE STRONG SOUTHERLY WINDS TO CONTINUE THROUGH
THU. A TRAILING COLD FRONT TO MOVE THROUGH THE WATERS LATE THU
NIGHT INTO EARLY FRI MORNING. EXPECT WINDS TO SWITCH TO
SOUTHWESTERLY AND DROP OFF CONSIDERABLY BEHIND THE FRONTAL
PASSAGE. ANOTHER LOW PRES SYSTEM TO APPROACH THE S OREGON COAST
FRI NIGHT INTO SAT...BUT CURRENTLY EXPECT THIS SYSTEM WILL NOT
HAVE MUCH IMPACT FOR THE S WASHINGTON AND N OREGON COASTAL WATERS.
HIGH PRES BUILDS OVER THE WATERS FOR THE LATE WEEKEND AND EARLY
NEXT WEEK.
SEAS HAVE CONTINUED TO BE A FOOT OR TWO LOWER THAN GUIDANCE...BUT
REMAIN IN THE LOW TEENS. WILL SEE SEAS INCREASE LATER THIS
AFTERNOON AND THIS EVENING AS WINDS PICK UP...BUILDING INTO THE
MID TEENS TONIGHT AND LIKELY PEAKING IN THE UPPER TEENS LATE
THURSDAY. SEAS SUBSIDE BACK TO THE MID TEENS BY FRIDAY AND LOOK TO
FALL BELOW 10 FT SOMETIME THIS WEEKEND. PYLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...GALE WARNING UNTIL 10 PM PST THURSDAY FOR WATERS FROM CAPE
SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-WATERS
FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST THURSDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR
OUT 10 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 PM PST
THURSDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE
OR OUT 10 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM PST
THURSDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
[top]
Area Forecast Discussion
National Weather Service Spokane WA
242 PM PST WED JAN 20 2016
.SYNOPSIS...
A slow moving frontal system will bring locally heavy snow to the
Cascades and the Methow Valley tonight into Thursday. The front
will gradually move through eastern Washington and north Idaho on
Friday bringing light rain. Saturday will also feature the
potential for rain and mountain snow. High pressure should produce
mainly dry conditions Sunday and Monday before more valley rain
and mountain snow returns Tuesday.
&&
.DISCUSSION...
...HEAVY MOUNTAIN SNOW AND WINTRY MIX EAST SLOPES OF CASCADES
TONIGHT THROUGH FRIDAY MORNING...
Tonight through Friday morning: Satellite imagery shows the next
weather system knocking on our doorstep. The upper level low
pressure circulation is located out at 50N 135W in the Gulf of
Alaska. This low pressure system is tapping into a sub-tropical
moisture plume that extends out to the Hawaiian Islands. The
upper level trough will continue to dig as it approaches the
region. This will act to orient the moisture plume more
meridionally more along the western coast line. The warm front
currently pushing its way into northwest OR with light rain being
observed on radar along the coast. This front is progged to reach
the northern Cascades between 8:00 and 10:00 PM this evening based
off the latest HRRR guidance. Much of the region will see at least
a chance for some light precipitation as the front crosses eastern
WA and into the ID Panhandle overnight.
A southeasterly pressure gradient will strengthen overnight. This
will result in some downsloping off of the Northeast Blue Mtns and
off of the higher terrain in the ID Panhandle. I anticipate that
that this will act to hinder much precipitation from actually
reaching the ground across the Palouse, into the Lewiston-
Clarkston Vly and up on the Camas Prairie. Generally only some
light precipitation is anticipated with the warm front across much
of eastern WA and in the ID Panhandle.
Areas that will benefit from the easterly gradient will be the
East Slopes of the Northern Cascades. The combination of moist
isentropic ascent and orographics should keep these areas wet.
Snow levels are going to be very tricky with this system.
Valleys that saw some sun across this area this afternoon should
have a difficult time cooling back down below freezing overnight.
Higher clouds are already moving in and this should act to keep
this warmer air from radiating completely away. However, the
Okanogan Valley and Methow Valley continue to see low clouds,
which has kept their temperatures down in the low 30s. These
locations will see a better chance for accumulating snow;
although, I am not as confidence about the Okanogan Valley. I
think surface temperatures will be too warm for much of the
Wenatchee Area for snow to stick, especially right along the
Columbia River. I also think that Wenatchee River Valley, Entiat
River Valley and communities along Lake Chelan will have a
difficult time seeing snow accumulate. The Winter Storm Watch will
be upgraded to a Warning for heavy snow, but will largely only
includes locations below 3000 feet south of Lake Chelan. The upper
reaches of the Methow Valley will also see a good chance for heavy
snow accumulations. The warning will run from tonight and continue
into Friday morning until the cold front passes through. I also
kept a possibility for freezing rain in the east slopes of the
northern Cascades and colder pockets in the Wenatchee Area. My
confidence is low since way did see some warming today, but cannot
completely rule it out. /SVH
Friday: The frontal system hung up along the Cascades Thursday and
Thursday night will finally be shoved eastward on Friday. There
will be a good deal of deep layer moisture accompanying the front
as it moves through eastern Washington and north Idaho, but not a
lot of large scale forcing. The models hardly depict a surface low
with the weak 500mb shortwave trough...an indication of weak
forcing. So despite an abundance of moisture, precipitation
amounts will be relatively light compared to some of our recent
storm systems. Snow levels will be high Friday and Friday night
with lowland communities region-wide receiving rain. One area of
exception could be the Methow Valley where the NAM and GFS depict
a bit of cooler air trapped along the Cascades which could
contribute to light snow accumulations Friday morning.
Saturday and Sunday: Saturday has the potential to be cool and wet
as a weakening upper low moves into Oregon and falls apart. The
GFS and Canadian models sustain a weak deformation band Saturday
into Saturday night which produces a tenth to a quarter of an inch
or precipitation for eastern Washington and north Idaho. The NAM
and ECMWF split this feature suggesting lower precipitation
chances for our region Saturday. This system bears watching since
snow levels will be marginal for accumulations in the lee of the
Cascades into portions of Washington and Idaho near the Canadian
border. However, given the daytime arrival of precipitation, snow
may struggle to accumulate on roads. There is good model agreement
that Sunday will be drier with orographic snow showers mainly
limited to the mountains of the Idaho Panhandle. The sun may even
make an appearance Sunday along the east slopes of the Cascades
into portions of the Columbia Basin. /GKoch
Sunday night through Wednesday...Models are in good agreement of
an upper level ridge over the region Sunday night through Monday
night. This should result in dry conditions with areas of low
clouds and patchy fog in the valleys and Columbia Basin. The ridge
moves east on Tuesday allowing a weak short wave trough to pass
through the Inland NW bringing with it a chance for light rain and
snow. GFS Ensembles show quite a bit of spread regarding the
timing of this wave and would not be surprised to see the timing
delayed until Tuesday night or Wednesday. Models then show a
milder and wetter system for next Wednesday or Thursday. Near to
slightly above normal temperatures are expected in the extended
forecast period. JW
&&
.AVIATION...
18Z TAFS: The main aviation concern for the rest of today will be
fog and low stratus. Satellite imagery shows much of these low
clouds banked up along the periphery of the upper Columbia Basin.
This will continue to impact the KGEG, KSFF and KCOE TAF sites
as well as extend up the Okanogan Valley and valleys across NE WA
and into the ID Panhandle with IFR/MVFR conditions. KPUW should
see improving cigs through the morning and is expected to scatter
out in the afternoon. Easterly winds are also expected to scatter
out the Spokane/Coeur d`Alene corridor this evening. The focus
will then shift across the east slopes of the Cascades for
tonight. A warm front will increase precip chances at KEAT after
08Z. This precip is expected to begin as snow and should be very
wet with surface temps right around freezing. A warm tongue moving
in aloft will then increase the possibility for freezing rain
early Thursday morning, but there is uncertainty if surface temps
will be below freezing. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 34 42 36 42 33 39 / 20 50 20 60 40 50
Coeur d`Alene 33 41 35 42 33 39 / 10 50 20 70 50 50
Pullman 35 46 38 46 34 40 / 10 20 10 60 40 50
Lewiston 36 51 41 50 37 44 / 10 20 10 30 30 50
Colville 32 39 34 40 33 37 / 30 80 50 60 40 40
Sandpoint 32 38 35 40 33 38 / 20 60 20 80 60 50
Kellogg 31 40 36 40 31 36 / 10 40 20 70 60 60
Moses Lake 34 43 34 44 32 40 / 30 50 30 40 20 50
Wenatchee 34 39 35 42 31 37 / 90 90 80 90 20 50
Omak 32 36 33 39 29 35 / 70 100 80 90 20 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Winter Storm Warning from 10 PM this evening to 10 AM PST Friday
for East Slopes Northern Cascades.
&&
$$
AREA FORECAST DISCUSSION
NWS SEATTLE WA
840 AM PST WED JAN 20 2016
.SYNOPSIS...AN UPPER LEVEL RIDGE WILL BRING DRIER WEATHER TO WESTERN
WASHINGTON TODAY WITH A FEW SUN BREAKS. A FRONTAL SYSTEM WILL MOVE
SLOWLY ACROSS THE REGION TONIGHT THROUGH THURSDAY NIGHT...FOR A
PERIOD OF WET WEATHER. THE FRONT WILL MOVE EAST FRIDAY...AND A WEAK
UPPER LEVEL TROUGH WILL BE OVER THE AREA THIS WEEKEND. ANOTHER FRONT
SHOULD ARRIVE EARLY NEXT WEEK.
&&
.SHORT TERM...A WEAK UPPER LEVEL RIDGE CENTERED JUST OFFSHORE AT
16Z/8 AM THIS MORNING WILL MOVE OVER W WA THIS AFTERNOON. AS
EXPECTED SOME RESIDUAL SHOWERS REMAIN OVER THE AREA. HRRR AND 12Z
GFS AGREE THAT THE SHOWERS SHOULD DISSIPATE BY AROUND MIDDAY.
THE LEADING EDGE OF AN APPROACHING WET FRONTAL SYSTEM WAS JUST
OFFSHORE THIS MORNING WITH THE COLD FRONT OUT ALONG 135W. WITH THE
LEADING EDGE OF THE HIGHER CLOUDS WAS JUST 60 NM OFFSHORE THIS
MORNING SO ANY SUN BREAKS OVER W WA ARE GOING TO HAVE TO HAPPEN
BETWEEN NOW AND MIDDAY...SINCE THE OVERCAST HIGH CLOUDS WILL
PROBABLY COVER W WA EARLY THIS AFTERNOON. MODELS AGREE THAT LIGHT
RAIN WILL SPREAD OVER THE COAST LATE THIS AFTERNOON THEN SPREAD NE
ACROSS ALL OF W WA BY 06Z/10 PM.
THE WARM FRONT FROM THIS SYSTEM WILL BRING STRONG WARM ADVECTION
WITH 40-60 KT S-SW WINDS ALOFT FROM 925MB-850MB TO W WA. THIS WILL
PRODUCE HEAVY RAIN OVER THE OLYMPICS AND N CASCADES TONIGHT THROUGH
THURSDAY NIGHT. THE WARM FRONT LOOKS LIKE IT GRADUALLY WEAKENS ON
THURSDAY...BUT STRONG LOW LEVEL WINDS AHEAD OF THE OFFSHORE COLD
FRONT WILL KEEP THE RAIN GOING THURSDAY NIGHT INTO EARLY FRIDAY
MORNING. TOTAL PRECIP OVER THE AREA TONIGHT THROUGH FRIDAY MORNING
WILL BE AROUND 3-6 INCHES OVER THE OLYMPICS AND N CASCADES WITH 0.50-
1.00 OVER THE INTERIOR LOWLANDS. SNOW LEVELS WILL RISE TO AROUND
7000 FEET BY MIDDAY THURSDAY.
WEAK AND COOL EASTERLY FLOW THROUGH THE CASCADE PASSES SHOULD ALLOW
A FEW INCHES OF LIGHT SNOW TO FALL INTO THURSDAY MORNING...BUT THE
STRONG WARMING ALOFT WILL PROBABLY OVERWHELM THE COOL EAST LOW LEVEL
FLOW FOR A CHANGE OVER TO RAIN BEFORE MIDDAY THURSDAY.
THE COLD FRONT WILL FINALLY BE PUSHED INLAND FRIDAY MORNING ALLOWING
THE RAIN TO TAPER OFF. A WEAK UPPER LEVEL RIDGE WILL MOVE OVER THE
AREA FRIDAY AFTERNOON FOR GRADUAL DRYING. KAM
.LONG TERM...PREVIOUS DISCUSSION FROM THE 236 AM AFD...AN UPPER
TROUGH WILL BE CENTERED OVER THE NORTHERN CALIFORNIA OFFSHORE WATERS
FRIDAY NIGHT AND LIFT NORTHEAST ACROSS THE PACIFIC NORTHWEST
SATURDAY AND SATURDAY NIGHT. IT SHOULD BRING SOME SHOWERS TO THE
FORECAST AREA BUT NOTHING SIGNIFICANT. THE SNOW LEVEL WILL BE 3000
TO 4000 FT. DRIER WEATHER IS LIKELY SUNDAY AND MONDAY AS AN UPPER
RIDGE PROGRESSES SLOWLY ACROSS THE REGION.
MODELS ARE IN FAIRLY GOOD AGREEMENT THAT ANOTHER FRONTAL SYSTEM
WILL BRING THE NEXT ROUND OF STEADY WIDESPREAD PRECIPITATION
MONDAY NIGHT AND TUESDAY...PROBABLY WITH SNOW LEVELS AGAIN
CLIMBING TO AROUND 6000 FT. MCDONNAL
&&
.AVIATION...WESTERLY FLOW ALOFT WILL TURN SOUTHWESTERLY LATE THIS
AFTERNOON AS A FRONT APPROACHES THE COAST. SURFACE GRADIENTS WILL
BECOME INCREASINGLY SOUTHEASTERLY. THE AIR MASS IS MOIST AND STABLE.
IT WILL DRY SOMEWHAT THIS AFTERNOON THEN BECOME INCREASINGLY MOIST
FROM THE WEST TONIGHT AS THE FRONT MOVES ONTO THE COAST.
CONDITIONS ARE QUITE VARIABLE ACROSS THE AREA THIS MORNING WITH
MAINLY MVFR CEILINGS AND SOME IFR CEILINGS IN THE INTERIOR VALLEYS.
EXPECT THE LOWER LEVELS TO DRY OUT MIDDAY AS LOW LEVEL PRESSURE
GRADIENTS BECOMING INCREASINGLY OFFSHORE. PRECIPITATION WILL MOVE IN
FROM THE WEST THIS EVENING...BUT WITH EASTERLY PRES GRADIENTS
CEILINGS AND VISIBILITY WILL START AS VFR THIS EVENING...THEN
GRADUALLY DETERIORATE ON THE OLYMPIC PENINSULA OVERNIGHT WHILE
STAYING MAINLY VFR IN THE INTERIOR.
KSEA...SEVERAL CLOUD LAYERS BELOW 4K FT THIS MORNING INCLUDING
ONE BELOW 1K FT. CONDITIONS WILL IMPROVE TO GOOD VFR AROUND
20Z. CEILINGS WILL GRADUALLY FALL TO OVC035 LATE TONIGHT WITH -RA.
WINDS WILL BE SOUTH 4-8 KT THIS MORNING AND WILL TURN TO THE EAST OR
NORTHEAST 4-7 KT AFTER ABOUT 20Z. CHB
&&
.MARINE...A STRONG FRONT WILL MOVE INTO THE COASTAL WATERS THIS
EVENING AND THEN SLOWLY MOVE INLAND TONIGHT AND THURSDAY. GALE
WARNINGS ARE IN EFFECT FOR THE COAST AND THE CENTRAL AND EASTERN
STRAIT. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE REMAINING
WATERS EXCEPT PUGET SOUND AND HOOD CANAL.
SEAS WILL BUILD TONIGHT AND THURSDAY...BUT THE HIGHEST SEAS ON THE
ORDER OF 17 TO 19 FEET FROM THE SOUTHWEST WILL REMAIN OVER THE OUTER
WATERS AND WILL BE RELATIVELY SHORT PERIOD IN NATURE - REDUCING THE
THREAT FOR SIGNIFICANT BEACH EROSION ON THE COASTLINE.
A WEAKER SYSTEM WILL MOVE THROUGH THE WATERS FRIDAY OR FRIDAY NIGHT.
A STRONGER SYSTEM WILL MOVE BY WELL TO THE SOUTH OF THE WATERS ON
SATURDAY. CHB
&&
.HYDROLOGY...ANOTHER 3 TO 6 INCHES OF PRECIPITATION WILL FALL OVER
THE OLYMPICS TONIGHT THROUGH THURSDAY NIGHT...WITH THE SNOW LEVEL
RISING TO 6500 TO 7500 FT. THIS WILL CAUSE THE SKOKOMISH RIVER --
WHICH ONLY FELL BELOW FLOOD STAGE TUESDAY MORNING -- TO FLOOD
AGAIN. IT WILL PROBABLY BEGIN THURSDAY MORNING...AND THE ONLY
REAL QUESTION IS WHETHER OR NOT IT WILL REACH ITS MAJOR FLOOD
STAGE. THE FLOOD WATCH WILL BE UPDATED EARLY THIS MORNING.
OTHER WESTERN WASHINGTON RIVERS FLOWING OFF THE OLYMPICS AND THE
NORTH CASCADES WILL ALSO RISE SIGNIFICANTLY. HOWEVER NORTHWEST
RIVER FORECAST CENTER GUIDANCE SHOWS MOST OF THESE RIVERS -- THE
SATSOP... ELWHA...DUNGENESS...SKAGIT...AND STILLAGUAMISH --
CRESTING AT MOST WITH AROUND 70 PERCENT OF THE DISCHARGE NEEDED TO
REACH FLOOD STAGE. SO THE THREAT ON THESE RIVERS LOOKS PRETTY LOW.
THE GUIDANCE FOR THE NOOKSACK SHOWS IT GETTING CLOSEST TO FLOOD
STAGE -- THE SOUTH FORK NOOKSACK SPECIFICALLY -- BUT STILL LESS
THAN 80 PERCENT OF THE DISCHARGE CORRESPONDING TO FLOOD STAGE.
AND IT IS WORTH NOTING THAT THE NOOKSACK DID NOT FLOOD DURING
EITHER OF THE WESTERN WASHINGTON FLOODING EPISODES IN NOVEMBER AND
DECEMBER. BOTTOM LINE IS I WILL UPDATE THE FLOOD POTENTIAL OUTLOOK
TO STATE THAT FLOODING IS UNLIKELY ON RIVERS OTHER THAN THE
SKOKOMISH.
OTHERWISE...RIVER FLOODING IS NOT EXPECTED THE NEXT 7 DAYS.
MCDONNAL
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...FLOOD WATCH FROM THIS EVENING THROUGH LATE FRIDAY NIGHT FOR HOOD
CANAL AREA-LOWER CHEHALIS VALLEY AREA-OLYMPICS.
PZ...SMALL CRAFT ADVISORY COAST UNTIL 4 PM PST THIS AFTERNOON.
GALE WARNING COAST...CENTRAL AND E STRAIT FROM 4 PM THIS
AFTERNOON TO 7 PM PST THURSDAY.
SMALL CRAFT ADVISORY FOR ROUGH BAR UNTIL 7 PM PST THURSDAY FOR
GRAYS HARBOR BAR.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 7 PM PST THURSDAY
FOR ADMIRALTY INLET-NORTHERN INLAND WATERS INCLUDING THE
SAN JUAN ISLANDS.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 7 PM PST
THURSDAY FOR WEST ENTRANCE U.S. WATERS STRAIT OF JUAN DE
FUCA.
&&
$$
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