Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/25/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
909 PM MST THU JAN 22 2015
.SYNOPSIS...AN UPPER LOW WILL DROP SOUTH ALONG THE NEW MEXICO
BORDER THROUGH THIS EVENING GENERATING A FEW SHOWERS ALONG THE
BORDER AND FORCING COLDER ACROSS THE STATE ON NORTHERLY BREEZES.
DRY AND MILDER WEATHER WILL RETURN THIS WEEKEND BEFORE A LOW WEST
OF BAJA DIRECTS MOISTURE NORTH AND BRINGS A THREAT OF SHOWERS TO
SOUTHERN ARIZONA SUNDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...EASTERLY SURFACE FLOW WILL CONTINUE THROUGH TOMORROW
AFTERNOON FOR MOST LOCATIONS. SURFACE GRADIENT WILL RELAX SOME
DURING THE DAY...WHICH WILL ALLOW WINDS TO DIMINISH SOME.
STILL...EXPECT ELEVATED EASTERLY WINDS TO PERSIST OVER THE NEXT
FEW DAYS. THEN FOCUS TURNS TO THE PROGGED CUTOFF LOW OFF WESTERN
BAJA COAST. THIS SYSTEM WILL ADVECT MOISTURE INTO THE AREA BRING
BACK THE POTENTIAL FOR PRECIPITATION EARLY NEXT WEEK. SEE PREV
DISCUSSION FOR FURTHER DETAILS. ALL IN ALL...CURRENT FORECAST IS
IN GOOD SHAPE SO NO UPDATES NEEDED AT THIS TIME.
&&
.AVIATION...VALID THRU 24/06Z.
VFR CONDITIONS WILL PREVAIL IN AND AROUND THE TERMINALS OVER THE
NEXT 24 HOURS. LOWER CEILINGS ARE POSSIBLE EAST OF KDUG AS AN AREA
OF LOW PRESSURE MOVES EAST OF THE AREA. LOW CLOUDS MAY OBSCURE
TERRAIN AT TIMES IN AND AROUND THE CHIRICAHUA MOUNTAINS. EAST
WINDS WILL IMPACT MOST AREAS OVERNIGHT WITH GUSTS AS HIGH AS 25
MPH. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...BRISK EAST WINDS WILL IMPACT MOST AREAS OVERNIGHT.
WIND GUSTS AS HIGH AS 25 MPH WILL BE POSSIBLE. DRY AND STABLE
WEATHER WILL BUILD BACK IN WITH WARMING TEMPERATURES THROUGH THE
WEEKEND.
MOISTURE WILL BE ON THE INCREASE EARLY NEXT WEEK AS LOW PRESSURE OFF
BAJA COAST LIFTS NORTH. SHOWER POTENTIAL WILL BE ON THE
INCREASE...WITH THE BEST CHANCE OVER WESTERN PORTIONS OF PIMA
COUNTY.
&&
.PREV DISCUSSION... /ISSUED 254 PM MST THU JAN 22 2015/
DISCUSSION...PRIMARY CONCERN FOR THE NEXT WEEK IS THE POTENTIAL FOR
SHOWERS...AND POSSIBLY A FEW THUNDERSTORMS...MONDAY AND TUESDAY.
MORE ON THAT IN A MOMENT.
CURRENTLY...VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW
THE LOW CLOUDS AND LIGHT PRECIP ONGOING JUST ALONG THE AZ AND NEW
MEXICO BORDER. IN ADDITION...THE TIGHT PRESSURE GRADIENT IN PLACE
ACROSS SOUTHEAST AZ IS RESULTING IN GUSTY SURFACE WINDS. FOR
TONIGHT...WRF AND HRRR OUTPUT SUGGESTS EASTERLY LOW LEVEL FLOW WILL
CONTINUE THROUGH THE MORNING HOURS. THE RESULTING DOWNSLOPE WINDS
SHOULD KEEP LOW TEMPERATURES A FEW DEGREES HIGHER THAN MOS GUIDANCE
SUGGESTS IN VALLEY LOCATIONS TO THE WEST OF MOUNTAIN RANGES...THIS
INCLUDES LOCATIONS SUCH AS TUCSON AND SAFFORD.
THE UPPER LEVEL PATTERN MOVES INTO A TRANSITIONAL PHASE STARTING
TOMORROW AS THE UPPER LEVEL LOW PRESSURE SYSTEM IN NEW MEXICO SWEEPS
TO THE EAST...AND HIGH PRESSURE BUILDS OVER THE WESTERN U.S.. A
PRONOUNCED SHORT WAVE TROUGH EMBEDDED IN THE UPPER RIDGE DIVES SOUTH
TOWARD ARIZONA TOMORROW MORNING. THIS SHORT WAVE EVENTUALLY DIGS
SOUTHWEST...INTENSIFIES...AND BECOMES CUT OFF FROM THE MAIN PATTERN
JUST OFF THE COAST OF BAJA CALIFORNIA. THIS RESULTS IN AN UPPER
LEVEL REX BLOCK PATTERN WHERE WITH THE INTENSE HIGH PRESSURE RIDGE
EXTENDING OVER THE PACIFIC NORTHWEST AND THE CUT OFF LOW OFF THE
BAJA PENINSULA. THIS PATTERN SHOULD STICK AROUND FOR A FEW DAYS AND
WHILE THE PACIFIC NORTHWEST HEATS UP TO NEAR RECORD LEVELS...THOSE
OF US IN THE SOUTHWEST WILL SEE TEMPERATURES WARM UP A FEW DEGREES
ABOVE AVERAGE. IN ADDITION...MOIST AIR FROM THE PACIFIC WILL BE
TRANSPORTED BY THE LOW PRESSURE SYSTEM INTO SOUTHERN ARIZONA. BY
TUESDAY MORNING...PRECIPITABLE WATER VALUES WILL SKYROCKET TO AROUND
1 INCH...WHICH DOES NOT SEEM HIGH...BUT IS ACTUALLY NEAR THE 99TH
PERCENTILE FOR MID JANUARY.
ONCE THE CUT OFF LOW DISLODGES FROM THE BLOCKING PATTERN ON
MONDAY...IT WILL PUSH NORTH AND BING THE MOISTURE...ALONG WITH
PLENTY OF LIFT...TO SUPPORT PRECIPITATION ACROSS SOUTHEAST ARIZONA.
RIGHT NOW...IT APPEARS THE BEST SHOT FOR PRECIPITATION WILL TAKE
PLACE TUESDAY MORNING THROUGH THE AFTERNOON HOURS. SNOW LEVELS
SHOULD REMAIN FAIRLY HIGH AS THIS SYSTEM WILL BE RELATIVELY WARM FOR
MID JANUARY GIVEN ITS TIME SPENT OFF THE BAJA PENINSULA. RIGHT
NOW...WE ARE THINKING SNOW LEVELS MAY FALL TO AROUND 8000 FEET OR
SO. THEIR SHOULD BE SUFFICIENT COLD AIR ALOFT...AND WARM LOW LEVEL
AIR...TO SUPPORT A LIGHTNING STRIKE OR TWO. THE CURRENT FORECAST
DOES NOT MENTION THUNDERSTORMS AS I AM NOT CONFIDENT ON EXACTLY
WHERE THUNDER IS MOST LIKELY...BUT THE FAVORED AREA IS PIMA COUNTY
TO THE WEST. RAINFALL AMOUNTS ARE STILL UP IN THE AIR...BUT WE COULD
SEE A FEW TENTHS WITH A ISOLATED AMOUNTS NEAR ONE HALF INCH.
FOLLOWING THE EARLY WEEK SYSTEM...THE UPPER PATTERN BECOMES MORE
PROGRESSIVE AND GIVES WAY TO SHORT TERM RIDGING THROUGH MID
WEEK...FOLLOWED BY ANOTHER LOW PRESSURE SYSTEM BY NEXT WEEKEND. THE
ECMWF EVEN SUGGESTS ANOTHER REX BLOCK PATTERN STARTING NEXT
FRIDAY...WHILE THE GFS IS MORE PROGRESSIVE AND BRINGS A TROUGH
THROUGH BY SATURDAY. EITHER WAY...THE LONG TERM FORECAST IS FAIRLY
UNSETTLED AT THIS POINT.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS ALBANY NY
851 PM EST SAT JAN 24 2015
.SYNOPSIS...
BEHIND A DEPARTING COASTAL STORM...SOME LINGERING SNOW
SHOWERS OR PATCHY FREEZING DRIZZLE WILL OCCUR THIS EVENING. A COLD
FRONT WILL MOVE ACROSS THE REGION LATE TONIGHT WITH SOME ADDITIONAL
SNOW SHOWERS...MAINLY FOR NORTHWESTERN PARTS OF THE AREA. AN ARCTIC
AIR MASS MOVING IN BEHIND THIS FRONT WILL ALLOW FOR MUCH COLDER
TEMPERATURES ON SUNDAY. ANOTHER COASTAL STORM WITH ACCUMULATING SNOW
IS POSSIBLE DURING THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
...WINTER WEATHER ADVISORY FOR AREAS OF FREEZING DRIZZLE ISSUED
FOR MOHAWK AND SCHOHARIE VALLEYS...HELDERBERGS...AND EASTERN
CATSKILLS.
AS OF 850 PM EST...IR SATELLITE SHOWS A BROAD AREA OF LOW CLOUDS
SPREADING INTO OUR WESTERN ZONES FROM CENTRAL NY. THE LACK OF ICE
NUCLEI IN SOME AREAS IS ALLOWING FOR SOME FREEZING DRIZZLE IN
SPOTS UPSTREAM...WITH SOME LIGHT SNOW SHOWERS ELSEWHERE.
EVEN THOUGH RADAR DOESN/T SHOW MUCH...ENOUGH REPORTS UPSTREAM...ALONG
WITH COLLABORATION WITH WFO BGM...HAS WARRANTED THE ISSUANCE OF A
SHORT FUSED WSW FOR FREEZING DRIZZLE. WILL ALLOW FOR AREAS OF
FREEZING DRIZZLE AND A CHANCE FOR -SHSN FOR WESTERN AREAS THROUGH
LATE THIS EVENING. WHILE TRACE AMOUNTS ARE EXPECTED...IT WILL BE
ENOUGH TO MAKE SURFACES SLICK...ESP UNTREATED ONES.
THE 3KM HRRR SHOWS THIS ACTIVITY WEAKENING AND DRYING UP AS IT
MOVES FURTHER EASTWARD...AND 00Z KALY SOUNDING WOULD SUGGEST DRY
AIR WOULD PROBABLY WIN OUT. STILL...WILL CONTINUE TO MONITOR AS IT
PROGRESSES FURTHER EASTWARD. WITH COLDER AIR AND DEEPENING
MOISTURE ALOFT ARRIVING AHEAD OF THE NEXT FRONTAL SYSTEM...PTYPE
SHOULD CHANGE TO SNOW SHOWERS EVERYWHERE BY ABOUT MIDNIGHT...SO
-FZDZ CONCERN IS REALLY ONLY FOR NEXT FEW HOURS.
THE COLD FRONT LOCATED TO OUR NORTHWEST ACROSS THE EASTERN GREAT
LAKES ASSOCIATED WITH NORTHERN STREAM ENERGY WILL MOVE
SOUTHEASTWARD INTO THE AREA LATE TONIGHT. SCATTERED SNOW SHOWERS
WILL PRECEDE AND ACCOMPANY THE BOUNDARY AND SHORT WAVE FOR THE
ADIRONDACKS...WITH LITTLE ACTIVITY EXPECTED FURTHER SOUTH AND
EAST.
TEMPERATURES WILL DROP ONLY GRADUALLY TONIGHT AS THE COLD FRONT
APPROACHES...AND MAY WIND UP HOLDING STEADY FOR MANY LOCATIONS IN
THE MID TO UPPER 20S. FAR NORTHWESTERN AREAS MAY FALL LATE
TONIGHT INTO THE TEENS AS THE COLD FRONT PASSES.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
THE PASSAGE OF THE COLD FRONT IS EXPECTED AROUND DAY BREAK ACROSS
THE NORTHWESTERN PORTION OF THE FORECAST AREA AND BEFORE MIDDAY
ACROSS THE SOUTHEAST. HIGHER PRESSURE WILL BEGIN TO BUILD IN BEHIND
THE BOUNDARY DURING THE AFTERNOON. THERE WILL BE LITTLE RECOVERY IN
TEMPERATURES SUNDAY WITH THE COLD AIR ADVECTION IN THE WAKE OF THE
BOUNDARY. IN ADDITION THE BRISK NORTHWESTERLY WINDS WILL MAKE IN
FEEL EVEN COLDER.
HIGH PRESSURE CENTERED TO OUR NORTH WILL PASS OVER THE REGION SUNDAY
NIGHT INTO MONDAY AS AN AREA OF LOW PRESSURE PASSES TO OUR SOUTH IN
ASSOCIATION WITH A VIGOROUS SHORT WAVE. THE SURFACE LOW IS THEN
EXPECTED TO MOVE OFF THE CAROLINA COAST ON MONDAY. HOWEVER ALOFT AN
UPPER LOW IS EXPECTED TO DEVELOP ALONG THE MID ATLANTIC COAST MONDAY
NIGHT AS THE SHORT WAVE ROTATES THROUGH THE BASE OF THE DEEP LONGWAVE
TROUGH OVER THE EASTERN UNITED STATES. THIS WILL RESULT IN FURTHER
DEVELOPMENT/DEEPENING OF THE SURFACE LOW OFF THE MID ATLANTIC COAST.
IT WILL BE COLD AND FAIR SUNDAY NIGHT AS THE RIDGE DOMINATES OUR
WEATHER. LOWS ARE FORECAST TO BE IN THE SINGLE DIGITS WITH BELOW
ZERO READINGS ACROSS THE NORTHWESTERN THIRD OF THE FORECAST AREA.
WINDS WILL BE LIGHT. TEMPERATURES MONDAY ARE EXPECTED TO RUN AROUND
10 DEGREES BELOW NORMAL.
AT THIS TIME IT APPEARS THE FORECAST AREA MAY BE ON THE NORTHERN
EDGE OF THE PRECIPITATION SHIELD MONDAY WITH GREATER AND MORE
WIDESPREAD CHANCES FOR SNOW MONDAY NIGHT AS THE SURFACE LOW
DEEPENS AND IS DRAWN UNDER THE UPPER LOW MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE LONG TERM PERIOD WILL START OFF ACTIVE...ALTHOUGH THE DEGREE OF
IMPACT IS STILL YET TO BE DETERMINED. IN ADDITION...RATHER COLD
WEATHER IS EXPECTED THROUGH THE ENTIRE LONG TERM PERIOD.
AS AN UPPER LEVEL DISTURBANCE DIVES OUT OF THE NORTHERN STREAM
TOWARDS THE EASTERN SEABOARD...A NEW AREA OF LOW PRESSURE WILL
DEVELOP OFF THE COAST AND RAPIDLY DEEPEN ON TUESDAY. THIS IS SHOWN
IN THE 12Z ECMWF...GGEM...GFS...NAM AND MOST MEMBERS OF THE 12Z
GEFS. THE UPPER LEVEL ENERGY WILL BECOME CUT OFF...ALLOWING FOR A
PROLONGED PERIOD OF PRECIP IN THE FORM OF SNOW TO OCCUR ACROSS MUCH
OF NEW ENGLAND. OUR REGION WILL BE ON THE WESTERN FRINGE OF THIS
SYSTEM...ALTHOUGH THE EXACT TRACK IS STILL FAR FROM CERTAIN. WHILE
SOME SNOW LOOKS TO OCCUR ON TUESDAY...AMOUNTS ARE STILL QUITE
UNCERTAIN...WITH THE BEST CHANCE ACROSS EASTERN PARTS OF THE AREA.
WHILE THE 12Z NAM/ECMWF BOTH HAD A LOT OF PRECIP OVER OUR AREA...THE
12Z GGEM/GFS AND 18Z NAM KEPT THE HEAVIER PRECIP TO OUR EAST. AT
THIS POINT...WILL FAVOR AREAS EAST OF THE HUDSON RIVER FOR THE MOST
SNOWFALL AND HIGHEST POPS FOR TUESDAY INTO TUESDAY NIGHT.
STILL...THERE IS POTENTIAL FOR THIS STORM TO TRACK CLOSER TO OUR
AREA AND BRING A SIGNIFICANT SNOWFALL TO THE ENTIRE CWA...AND THE
WITH THE UPPER LEVEL LOW BECOMING CUTOFF...THIS MAKES THE FORECAST
RATHER DIFFICULT AND PARTICULAR UNCERTAIN. WE WILL MENTION THIS
SYSTEM IN OUR HWO. TEMPS WILL CONTINUE TO BELOW NORMAL WITH AN
ARCTIC AIRMASS IN PLACE...WITH HIGHS ONLY IN THE TEENS AND 20S...AND
LOWS BETWEEN -10 AND 5.
BY WEDNESDAY...THE STORM WILL BE MOVING AWAY...BUT IT REMAIN COLD
AND BLUSTERY BEHIND THE SYSTEM. TEMPS WILL CONTINUE TO BE IN THE
TEENS AND 20S FOR WED...WITH SINGLE DIGITS FOR WED NIGHT. NO PRECIP
IS EXPECTED...WITH A PARTLY TO MOSTLY CLEAR SKY.
ANOTHER NORTHERN STREAM CLIPPER SYSTEM LOOK TO IMPACT THE REGION
SOMETIME BETWEEN THURSDAY AFTERNOON AND FRIDAY. A ROUND OF LIGHT
SNOW LOOKS TO SPREAD FROM WEST TO EAST ACROSS THE AREA...WITH SOME
ACCUMULATION POSSIBLE FOR ALL AREAS. TEMPS LOOK A LITTLE WARMER THAN
RECENT DAYS...WITH HIGHS IN THE 20S FOR THURS/FRI. OVERNIGHT LOWS ON
THURS NIGHT WILL BE IN THE MID TEENS TO MID 20S.
COLDER AIR WILL ARRIVE BEHIND THIS NORTHERN STREAM CLIPPER SYSTEM.
MIN ON FRI NIGHT WILL BE IN THE SINGLE DIGITS. IT WILL BE COLD AND
BLUSTERY FOR SATURDAY WITH A PARTLY CLOUDY SKY...AND HIGHS IN THE
TEENS.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS.
THE EXCEPTION WILL BE THIS EVENING...AS LINGERING LOW LEVEL
MOISTURE MAY ALLOW FOR A BRIEF PERIOD OF MVFR MIST/LOW
STRATUS...MAINLY FOR KGFL OR KPSF. OTHERWISE...ENOUGH OF A GRADIENT
THANKS TO AN APPROACHING COLD FRONT LATE TONIGHT SHOULD KEEP
THINGS MIXED ENOUGH TO PREVENT ANY MVFR/IFR LOW CLOUDS FROM
OCCURRING. OTHERWISE CIGS WILL BE BKN-OVC AT AROUND 5-6 KFT FOR
MOST OF THE NIGHT.
THE PASSAGE OF THE FRONT LOOKS TO OCCUR EITHER LATE TONIGHT OR
EARLY SUNDAY MORNING AFTER SUNRISE. THE WIND SHIFT WITH THIS
BOUNDARY WILL BE SUBTLE...DUE TO W-NW FLOW ALREADY IN PLACE BEHIND
THE DEPARTING COASTAL STORM. WINDS WILL BECOME MORE WESTERLY FOR
SUNDAY AT AROUND 10 KTS.
CLOUDS SHOULD DECREASE THROUGH THE DAY ON SUNDAY BEHIND THE ARCTIC
BOUNDARY...BECOMING NEARLY CLEAR IN MOST AREAS BY ABOUT MIDDAY.
LITTLE TO NO PRECIP IS EXPECTED WITH THE PASSAGE OF THE BOUNDARY
FOR VALLEY SITES DUE TO LIMITED MOISTURE.
OUTLOOK...
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
&&
.HYDROLOGY...
NO SIGNIFICANT HYDRO PROBLEMS ARE EXPECTED THROUGH EARLY NEXT WEEK.
THE PRECIPITATION THAT DOES OCCUR WILL BE IN THE FORM OF SNOW.
ICE WILL CONTINUE TO THICKEN ON RIVERS...STREAMS...CREEKS...LAKES
AND OTHER BODIES OF WATER.
THE EAGLE BRIDGE GAGE ON THE HOOSIC RIVER CONTINUES TO BE HAMPERED
BY ICE EFFECTS.
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...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
NYZ038>040-047-048-051-058-063.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...IAA/FRUGIS
SHORT TERM...IAA
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS ALBANY NY
642 PM EST SAT JAN 24 2015
.SYNOPSIS...
BEHIND A DEPARTING COASTAL STORM...SOME LINGERING SNOW
SHOWERS OR PATCHY FREEZING DRIZZLE WILL OCCUR THIS EVENING. A COLD
FRONT WILL MOVE ACROSS THE REGION LATE TONIGHT WITH SOME ADDITIONAL
SNOW SHOWERS...MAINLY FOR NORTHWESTERN PARTS OF THE AREA. AN ARCTIC
AIR MASS MOVING IN BEHIND THIS FRONT WILL ALLOW FOR MUCH COLDER
TEMPERATURES ON SUNDAY. ANOTHER COASTAL STORM WITH ACCUMULATING SNOW
IS POSSIBLE DURING THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 642 PM EST...COASTAL STORM CONTINUE TO DEPART AWAY FROM THE
AREA...AND STEADY SNOWFALL OVER WESTERN NEW ENGLAND HAS ENDED.
BACKEDGE OF THE CLOUDS CAN BE SEEN ON IR SATELLITE IMAGERY...AND
CLEARING SHOULD BE OCCURRING OVER WESTERN NEW ENGLAND SHORTLY.
AT THE SAME TIME...LOW LEVEL MOISTURE HAS BEEN INCREASING OVER
CENTRAL NY AND IS STARTING TO SPREAD TOWARDS THE ADIRONDACKS AND
WESTERN MOHAWK VALLEY. THE LACK OF ICE NUCLEI IN SOME AREAS IS
ALLOWING FOR SOME FREEZING DRIZZLE IN SPOTS UPSTREAM...WITH SOME
LIGHT SNOW SHOWERS ELSEWHERE. WILL CONTINUE TO ALLOW FOR PATCHY
FREEZING DRIZZLE AND A CHANCE FOR -SHSN FOR WESTERN AREAS THROUGH
LATE THIS EVENING. THE 3KM HRRR SHOWS THIS ACTIVITY GENERALLY
DISSIPATING AS IT REACHES OUR AREA...BUT WILL CONTINUE TO MONITOR. IF
FZDZ/FZRA BECOMES MORE WIDESPREAD...AN SPS OR WINTER WEATHER
ADVISORY WILL BE ISSUED.
A COLD FRONT LOCATED TO OUR NORTHWEST ACROSS THE EASTERN GREAT LAKES
ASSOCIATED WITH NORTHERN STREAM ENERGY WILL MOVE SOUTHEASTWARD INTO
THE AREA TONIGHT. SCATTERED SNOW SHOWERS WILL PRECEDE AND ACCOMPANY
THE BOUNDARY AND SHORT WAVE FOR THE ADIRONDACKS...WITH LITTLE
ACTIVITY EXPECTED FURTHER SOUTH AND EAST.
TEMPERATURES WILL DROP ONLY GRADUALLY TONIGHT AS THE COLD FRONT
APPROACHES...AND MAY WIND UP HOLDING STEADY FOR MANY LOCATIONS IN
THE MID TO UPPER 20S. FAR NORTHWESTERN AREAS MAY FALL LATE
TONIGHT INTO THE TEENS AS THE COLD FRONT PASSES.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
THE PASSAGE OF THE COLD FRONT IS EXPECTED AROUND DAY BREAK ACROSS
THE NORTHWESTERN PORTION OF THE FORECAST AREA AND BEFORE MIDDAY
ACROSS THE SOUTHEAST. HIGHER PRESSURE WILL BEGIN TO BUILD IN BEHIND
THE BOUNDARY DURING THE AFTERNOON. THERE WILL BE LITTLE RECOVERY IN
TEMPERATURES SUNDAY WITH THE COLD AIR ADVECTION IN THE WAKE OF THE
BOUNDARY. IN ADDITION THE BRISK NORTHWESTERLY WINDS WILL MAKE IN
FEEL EVEN COLDER.
HIGH PRESSURE CENTERED TO OUR NORTH WILL PASS OVER THE REGION SUNDAY
NIGHT INTO MONDAY AS AN AREA OF LOW PRESSURE PASSES TO OUR SOUTH IN
ASSOCIATION WITH A VIGOROUS SHORT WAVE. THE SURFACE LOW IS THEN
EXPECTED TO MOVE OFF THE CAROLINA COAST ON MONDAY. HOWEVER ALOFT AN
UPPER LOW IS EXPECTED TO DEVELOP ALONG THE MID ATLANTIC COAST MONDAY
NIGHT AS THE SHORT WAVE ROTATES THROUGH THE BASE OF THE DEEP LONGWAVE
TROUGH OVER THE EASTERN UNITED STATES. THIS WILL RESULT IN FURTHER
DEVELOPMENT/DEEPENING OF THE SURFACE LOW OFF THE MID ATLANTIC COAST.
IT WILL BE COLD AND FAIR SUNDAY NIGHT AS THE RIDGE DOMINATES OUR
WEATHER. LOWS ARE FORECAST TO BE IN THE SINGLE DIGITS WITH BELOW
ZERO READINGS ACROSS THE NORTHWESTERN THIRD OF THE FORECAST AREA.
WINDS WILL BE LIGHT. TEMPERATURES MONDAY ARE EXPECTED TO RUN AROUND
10 DEGREES BELOW NORMAL.
AT THIS TIME IT APPEARS THE FORECAST AREA MAY BE ON THE NORTHERN
EDGE OF THE PRECIPITATION SHIELD MONDAY WITH GREATER AND MORE
WIDESPREAD CHANCES FOR SNOW MONDAY NIGHT AS THE SURFACE LOW
DEEPENS AND IS DRAWN UNDER THE UPPER LOW MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE LONG TERM PERIOD WILL START OFF ACTIVE...ALTHOUGH THE DEGREE OF
IMPACT IS STILL YET TO BE DETERMINED. IN ADDITION...RATHER COLD
WEATHER IS EXPECTED THROUGH THE ENTIRE LONG TERM PERIOD.
AS AN UPPER LEVEL DISTURBANCE DIVES OUT OF THE NORTHERN STREAM
TOWARDS THE EASTERN SEABOARD...A NEW AREA OF LOW PRESSURE WILL
DEVELOP OFF THE COAST AND RAPIDLY DEEPEN ON TUESDAY. THIS IS SHOWN
IN THE 12Z ECMWF...GGEM...GFS...NAM AND MOST MEMBERS OF THE 12Z
GEFS. THE UPPER LEVEL ENERGY WILL BECOME CUT OFF...ALLOWING FOR A
PROLONGED PERIOD OF PRECIP IN THE FORM OF SNOW TO OCCUR ACROSS MUCH
OF NEW ENGLAND. OUR REGION WILL BE ON THE WESTERN FRINGE OF THIS
SYSTEM...ALTHOUGH THE EXACT TRACK IS STILL FAR FROM CERTAIN. WHILE
SOME SNOW LOOKS TO OCCUR ON TUESDAY...AMOUNTS ARE STILL QUITE
UNCERTAIN...WITH THE BEST CHANCE ACROSS EASTERN PARTS OF THE AREA.
WHILE THE 12Z NAM/ECMWF BOTH HAD A LOT OF PRECIP OVER OUR AREA...THE
12Z GGEM/GFS AND 18Z NAM KEPT THE HEAVIER PRECIP TO OUR EAST. AT
THIS POINT...WILL FAVOR AREAS EAST OF THE HUDSON RIVER FOR THE MOST
SNOWFALL AND HIGHEST POPS FOR TUESDAY INTO TUESDAY NIGHT.
STILL...THERE IS POTENTIAL FOR THIS STORM TO TRACK CLOSER TO OUR
AREA AND BRING A SIGNIFICANT SNOWFALL TO THE ENTIRE CWA...AND THE
WITH THE UPPER LEVEL LOW BECOMING CUTOFF...THIS MAKES THE FORECAST
RATHER DIFFICULT AND PARTICULAR UNCERTAIN. WE WILL MENTION THIS
SYSTEM IN OUR HWO. TEMPS WILL CONTINUE TO BELOW NORMAL WITH AN
ARCTIC AIRMASS IN PLACE...WITH HIGHS ONLY IN THE TEENS AND 20S...AND
LOWS BETWEEN -10 AND 5.
BY WEDNESDAY...THE STORM WILL BE MOVING AWAY...BUT IT REMAIN COLD
AND BLUSTERY BEHIND THE SYSTEM. TEMPS WILL CONTINUE TO BE IN THE
TEENS AND 20S FOR WED...WITH SINGLE DIGITS FOR WED NIGHT. NO PRECIP
IS EXPECTED...WITH A PARTLY TO MOSTLY CLEAR SKY.
ANOTHER NORTHERN STREAM CLIPPER SYSTEM LOOK TO IMPACT THE REGION
SOMETIME BETWEEN THURSDAY AFTERNOON AND FRIDAY. A ROUND OF LIGHT
SNOW LOOKS TO SPREAD FROM WEST TO EAST ACROSS THE AREA...WITH SOME
ACCUMULATION POSSIBLE FOR ALL AREAS. TEMPS LOOK A LITTLE WARMER THAN
RECENT DAYS...WITH HIGHS IN THE 20S FOR THURS/FRI. OVERNIGHT LOWS ON
THURS NIGHT WILL BE IN THE MID TEENS TO MID 20S.
COLDER AIR WILL ARRIVE BEHIND THIS NORTHERN STREAM CLIPPER SYSTEM.
MIN ON FRI NIGHT WILL BE IN THE SINGLE DIGITS. IT WILL BE COLD AND
BLUSTERY FOR SATURDAY WITH A PARTLY CLOUDY SKY...AND HIGHS IN THE
TEENS.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS.
THE EXCEPTION WILL BE THIS EVENING...AS LINGERING LOW LEVEL
MOISTURE MAY ALLOW FOR A BRIEF PERIOD OF MVFR MIST/LOW
STRATUS...MAINLY FOR KGFL OR KPSF. OTHERWISE...ENOUGH OF A GRADIENT
THANKS TO AN APPROACHING COLD FRONT LATE TONIGHT SHOULD KEEP
THINGS MIXED ENOUGH TO PREVENT ANY MVFR/IFR LOW CLOUDS FROM
OCCURRING. OTHERWISE CIGS WILL BE BKN-OVC AT AROUND 5-6 KFT FOR
MOST OF THE NIGHT.
THE PASSAGE OF THE FRONT LOOKS TO OCCUR EITHER LATE TONIGHT OR
EARLY SUNDAY MORNING AFTER SUNRISE. THE WIND SHIFT WITH THIS
BOUNDARY WILL BE SUBTLE...DUE TO W-NW FLOW ALREADY IN PLACE BEHIND
THE DEPARTING COASTAL STORM. WINDS WILL BECOME MORE WESTERLY FOR
SUNDAY AT AROUND 10 KTS.
CLOUDS SHOULD DECREASE THROUGH THE DAY ON SUNDAY BEHIND THE ARCTIC
BOUNDARY...BECOMING NEARLY CLEAR IN MOST AREAS BY ABOUT MIDDAY.
LITTLE TO NO PRECIP IS EXPECTED WITH THE PASSAGE OF THE BOUNDARY
FOR VALLEY SITES DUE TO LIMITED MOISTURE.
OUTLOOK...
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
&&
.HYDROLOGY...
NO SIGNIFICANT HYDRO PROBLEMS ARE EXPECTED THROUGH EARLY NEXT WEEK.
THE PRECIPITATION THAT DOES OCCUR WILL BE IN THE FORM OF SNOW.
ICE WILL CONTINUE TO THICKEN ON RIVERS...STREAMS...CREEKS...LAKES
AND OTHER BODIES OF WATER.
THE EAGLE BRIDGE GAGE ON THE HOOSIC RIVER CONTINUES TO BE HAMPERED
BY ICE EFFECTS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...IAA/FRUGIS
SHORT TERM...IAA
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
307 PM EST FRI JAN 23 2015
.DISCUSSION...
...STORMS ACROSS THE REGION THIS EVENING INTO EARLY SAT...
...HAZARDOUS BOATING CONDITIONS WILL WORSEN INTO SAT...
CURRENTLY-TONIGHT...AFTERNOON CUMULUS DEVELOPMENT HAS BEEN
SHALLOW AND THE LATEST RAP FORECAST SOUNDINGS ONLY SHOW A LITTLE
CAPE DEVELOPING ACROSS THE FAR NORTH...SO THE CHANCE FOR CELLS
TO FORM IN THE MORE SHEARED LOW LEVEL ENVIRONMENT AHEAD OF PRE
FRONTAL SQUALL LINE LOOKS LOW. BUT THE HRRR DOES SHOW SLIGHT
COVERAGE SO WE WILL HAVE TO WATCH FOR SHOWERS OR STORMS WITH SOME
ROTATION IN THAT AREA UNTIL AROUND SUNSET.
THE LATEST HRRR BRINGS THE SQUALL LINE INTO OUR NORTHERN SECTIONS
JUST AFTER 00Z AND CENTRAL SECTIONS AROUND 06Z. THIS IS A LITTLE
FASTER THAN EXTRAPOLATION BUT THIS PERIOD WILL BE WHEN WIND
PROFILES ARE STRENGTHENING DUE TO INTENSIFYING SURFACE LOW MOVING
NORTH OF THE STATE. SO SOME ACCELERATION IS EXPECTED. SEE NO
REASON TO DIFFER WITH THE MOS CATEGORICAL POPS ACROSS THE NORTH.
THE TRAILING SOUTHERN END OF THE LINE WILL PROBABLY BE SLOW TO
REACH SOUTHERN SECTIONS...SO WE WILL HAVE A WIDE POP RANGE FROM
NORTH TO SOUTH (90 PERCENT TO 20 PERCENT).
THE MAIN QUESTION IS HOW VIGOROUS THE CONVECTION WILL BE TONIGHT
WITH THE PRE FRONTAL LINE. THE MODELS CONTINUE TO SHOW MEAGER CAPE
BUT WITH INCREASING WIND PROFILES THE CELLS WILL BE VERY FAST
MOVING...IN A FLOW THAT BECOMES GRADUALLY MORE UNIDIRECTIONAL.
THEREFORE EXPECT SHOWERS/STORMS WITH STRONG WIND GUSTS. LOCALIZED
DAMAGING WINDS CANNOT BE RULED OUT THOUGH.
SAT...COLD FRONT WILL BE ACROSS OUR NORTHERN SECTIONS AT SUNRISE
THEN IN SOUTH FLORIDA BY AFTERNOON. FRONTAL CONVERGENCE SHOULD BE
WEAKENING AND EXPECT A MORE NARROW BAND OF CONVECTION TO TRAVERSE
THE AREA. LOWEST POPS WILL BE ACROSS THE NORTH (40 PERCENT) AND
HIGHEST IN THE SOUTH (60 PERCENT). THIS WOULD BE IN THE MORNING
HOURS...WITH A SLIGHT CHANCE OF LINGERING SHOWERS IN THE FAR
SOUTH. COLD ADVECTION WILL KICK IN ACROSS THE NORTH EARLY AND BY
AFTERNOON IN THE SOUTH SO HAVE GONE WITH SLIGHTLY COOLER CONSENSUS
TEMPS RATHER THAN THE GFS MOS.
SAT NIGHT... BROAD CYCLONIC FLOW OVER THE SOUTHEAST UNITED STATES.
SURFACE HIGH PRESSURE CENTERED OVER SOUTHEAST TEXAS RIDGES ACROSS
THE GULF OF MEXICO AND FLORIDA. THE RESULTING NORTHWEST SURFACE AND
LOW LEVEL WIND FLOW BRINGS A MUCH COOLER AND DRIER AIR MASS INTO
CENTRAL FLORIDA. OVERNIGHT LOWS MUCH COLDER WITH MINS FORECAST NEAR
40 DEGREES TO LOWER 40S...EXCEPT MIDDLE 40S ALONG THE IMMEDIATE
TREASURE COAST. WHILE WINDS ARE FORECAST TO DIMINISH IN THE
EVENING...THEY MAY STAY NEAR 10 MPH FOR A WHILE DURING THE EVENING.
BORDERLINE WIND CHILL ADVISORY CRITERIA POSSIBLE WITH CURRENT
FORECAST LOWEST WIND CHILL READINGS IN THE UPPER 30S OVER MUCH OF
THE AREA AFTER MIDNIGHT. MUCH DRIER AIR WILL ALSO FILTER DOWN THE
PENINSULA SAT OVERNIGHT.
PREVIOUS EXTENDED DISCUSSION
SUN-THU...COOLER AND DRIER FOR THIS ENTIRE PERIOD WITH A COUPLE OF
REINFORCING FRONTS PUSHING THROUGH THE AREA. WILL CONTINUE TO LEAVE
THE EXTENDED PRECIPITATION FREE OVER LAND. HIGHS MAINLY IN THE
60S...EXCEPT NEAR 70 DEGREES ACROSS THE TREASURE COAST ON MON. LOWS
MAINLY IN THE 40S AND NEAR 50 DEGREES ALONG THE IMMEDIATE TREASURE
COAST.
&&
.AVIATION...
CEILINGS HAVE BEEN VFR THIS AFTERNOON. BUT DURING THE OVERNIGHT
AND MORNING HOURS OF SAT...THAT WILL BE CHANGING AS A PERIOD OF
MVFR/IFR WILL OCCUR WITH BAND OF SHOWERS AND STORMS MOVING ACROSS
THE TERMINALS. GUSTINESS OF SOUTHERLY WINDS SHOULD DIMINISH
TOWARDS SUNSET...BUT STRONG WIND GUSTS WILL OCCUR WITH THE
SHOWERS/STORMS. AS LOW LEVEL WINDS INCREASE DURING THE NIGHT...
EXPECT MOST ALL OF THE TERMINALS TO HAVE LOW LEVEL WIND SHEAR...AND
HAVE ALREADY PUT THAT INTO THE TAFS. POST FRONTAL WINDS ON SAT
WILL BE STRONG AND GUSTY WITH SOME SITES HAVING GUSTS NEAR 30
KNOTS.
&&
.MARINE...
TONIGHT...SOUTHERLY WINDS HAVE STEADILY INCREASED AND WITH SURFACE
LOW MOVING INTO THE FLORIDA PANHANDLE WHILE STRENGTHENING...THE
PRESSURE GRADIENT WILL CONTINUE TO INCREASE. WILL LEAVE CURRENT
HEADLINES IN PLACE WITH ADVISORY STARTING NEARSHORE/GALE WARNING
OFFSHORE THIS EVENING.
SAT-SAT NIGHT...A GALE WARNING WILL CONTINUE UNTIL 21Z/4PM SAT
AFTN OFFSHORE AND NORTH OF SEBASTIAN INLET. SMALL CRAFT ADVISORIES
REMAINING IN PLACE LIKELY EVERYWHERE ELSE THROUGH THIS TIME...AND
RESUMING AFTER 21Z FOR OFFSHORE LEGS. INITIAL SW WINDS VERY EARLY
IN THE PERIOD WILL QUICKLY VEER TO W/WNW BEHIND FRONTAL PASSAGE IN
THE MORNING. WIND SPEEDS WILL GRADUALLY DIMINISH LATE SAT WITH
SEAS SLOWER TO RESPOND. SEAS INITIALLY BUILDING TO 4-6 FT NEAR
SHORE AND 6-8 FT OFFSHORE SLOWLY SUBSIDING TO 3-5 FT NEAR SHORE
AND 5-6 FT OFFSHORE BY DAYBREAK SUN MORNING.
SAT NIGHT...NORTHWEST WINDS 15 TO 20 KNOTS DIMINISH TO AROUND 15
KNOTS LATE OVERNIGHT/SUNRISE SUNDAY MORNING. SEAS 4 TO 7 FEET
SATURDAY EVENING SUBSIDE TO 3 TO 6 FEET DAYBREAK SUNDAY. STILL
HAZARDOUS CONDITIONS WITH AT LEAST A SMALL CRAFT OPERATORS EXERCISE
CAUTION ON THE COASTAL WATERS.
PREVIOUS EXTENDED MARINE DISCUSSION
SUN-TUE...UNSETTLED EXTENDED PERIOD AHEAD. THE PRESSURE GRADIENT
CONTINUES TO EASE ON SUN BUT THIS WILL BE SHORT-LIVED AS ANOTHER
FRONT IS FORECAST TO DROP ACROSS THE AREA SUN OVERNIGHT/MON WITH
WIND SPEEDS INCREASING TO ADVISORY LEVELS ONCE AGAIN. WINDS ARE SLOW
TO DIMINISH AGAIN INTO LATE TUE. SEAS CONTINUE TO SUBSIDE INTO
SUN BUT WILL BUILD BACK UPWARD LATE OVERNIGHT SUN THRU MON BEHIND
LATEST REINFORCING FRONTAL BOUNDARY. SEAS WILL AGAIN SUBSIDE LATE
TUE/TUE OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 62 67 39 64 / 90 40 10 10
MCO 64 68 41 66 / 70 40 10 10
MLB 67 71 41 65 / 50 50 10 10
VRB 68 73 43 66 / 30 60 10 10
LEE 62 64 41 66 / 90 30 10 10
SFB 63 68 41 66 / 80 40 10 10
ORL 64 67 43 67 / 80 40 10 10
FPR 69 74 43 66 / 30 60 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR COASTAL
VOLUSIA-INDIAN RIVER-INLAND VOLUSIA-MARTIN-NORTHERN BREVARD-
NORTHERN LAKE-OKEECHOBEE-ORANGE-OSCEOLA-SEMINOLE-SOUTHERN
BREVARD-SOUTHERN LAKE-ST. LUCIE.
AM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST
SATURDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA
BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM SEBASTIAN
INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM
VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM-
WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM
OFFSHORE.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60
NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO
SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
GALE WARNING FROM 10 PM THIS EVENING TO 4 PM EST SATURDAY FOR
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20
TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE
TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM...LASCODY
LONG TERM....WIMMER
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
344 PM EST FRI JAN 23 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE GULF OF MEXICO ACROSS
THE REGION TONIGHT. THE DEEPENING LOW WILL PULL AWAY TO THE
NORTHEAST SATURDAY...FOLLOWED BY WEAK HIGH PRESSURE FROM THE WEST
SUNDAY. AN AREA OF LOW PRESSURE WILL PASS WELL NORTH OF THE REGION
SUNDAY NIGHT AND EARLY MONDAY...WHICH WILL ALLOW FOR A PAIR OF
TRAILING COLD FRONTS TO SWING THROUGH SUNDAY NIGHT AND AGAIN LATE
MONDAY OR MONDAY NIGHT. HIGH PRESSURE WILL THEN BRING COLDER THAN
NORMAL TEMPERATURES INTO LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
A DEEP UPPER TROUGH DIGGING INTO THE ARKLATEX REGION CONTINUES TO
SUPPORT A DEEPENING SURFACE LOW NOW MOVING OUT OF THE CENTRAL GULF
OF MEXICO INTO SOUTHERN AL. MUCH OF OUR AREA HAS REMAINED UNDER
THE INFLUENCE OF A WEAK WEDGE OF HIGH PRESSURE EXTENDING IN FROM
THE NORTHEAST. A STRONG COASTAL TROUGH HAS PERSISTED JUST OFF THE
SC/GA COAST TODAY. HOWEVER WE ARE SEEING SIGNS OF IT FINALLY
SHIFTING INLAND WITH COASTAL WINDS VEERING TO SE. AS THE 850 MB
LOW LIFTS INTO THE SOUTHERN APPALACHIANS EARLY THIS EVENING A
45-55 KT LOW-LEVEL JET SETS UP ACROSS OUR WATERS. WE EXPECT THE
COASTAL TROUGH TO RAPIDLY SHIFT INLAND BY EARLY THIS EVENING WITH
GUSTY SOUTHERLY WINDS OVERSPREADING THE AREA AS THE SURFACE LOW
MOVES INTO CENTRAL GA/SC.
EARLY THIS AFTERNOON WE HAVE SEEN A NOTICEABLE SPLIT IN THE
PRECIPITATION ASSOCIATED WITH THIS SYSTEM. THE AREA OF HEAVIEST
RAIN HAS BEEN SHIFTING ACROSS NORTHERN FL AND EXTREME SE GA TOWARD
THE ATLANTIC WATERS. A SECOND AREA OF LIGHT TO MODERATE RAIN
EXTENDS FROM OUR INLAND AREAS INTO THE SC MIDLANDS AND CENTRAL
SAVANNAH RIVER AREA PRIMARILY DUE TO ISENTROPIC ASCENT AND MOIST
OVERRUNNING. THE LATEST HRRR AND RUC-13 PICK UP ON THESE SEMI-
DISCRETE AREAS FAIRLY WELL. THE SOUTHERN BATCH WILL MOSTLY MISS
OUR AREA TO THE SOUTH WHILE THE INLAND OVERRUNNING PRECIP WILL
SHIFT FARTHER INLAND AS THE COASTAL TROUGH SHIFTS INLAND AND MOST
AREAS ENTER THE WARM SECTOR.
WE WILL HANG ONTO MODERATE UPPER FORCING THROUGH THE NIGHT AND
ATMOSPHERIC MOISTURE WILL INCREASE STEADILY THIS EVENING. HOWEVER
WE COULD SEE A LULL IN WIDESPREAD RAINFALL FOR A FEW HOURS THIS
EVENING BEFORE THE FORCING RAMPS BACK UP AS THE SURFACE LOW
APPROACHES. THE COLD FRONT WILL PUSH INTO THE AREA FROM THE WEST
LATE TONIGHT WITH A FAIRLY CONTIGUOUS BAND OF SHOWERS AND PERHAPS
AN ELEVATED THUNDERSTORM. WE MAINTAINED CATEGORICAL POPS OVERNIGHT
BUT SIGNIFICANTLY LOWERED OUR STORM-TOTAL QPF SINCE THE BRUNT OF
THE HEAVIEST RAIN LOOKS TO STAY SOUTH.
TEMPERATURES WILL RISE THIS EVENING AS THE COASTAL TROUGH SHIFTS
INLAND...THEN WE EXPECT A SLOW FALL IN TEMPS LATE AS THE COLD
FRONT PUSHES IN FROM THE WEST.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY...A BROAD LARGE SCALE TROUGH WILL COVER MUCH OF THE EASTERN
STATES AS A STRONG AND NEUTRALLY TILTED SHORT WAVE ALONG THE SLOPES
OF THE CENTRAL/SOUTHERN APPALACHIANS AT DAYBREAK SWEEPS QUICKLY EAST
INTO THE ATLANTIC BY 15-18Z. AT THE SURFACE WE FIND A 996 MB
EXTRA-TROPICAL LOW MOVING THROUGH THE DELMARVA AT THE START OF THE
PERIOD BEFORE IT STARTS TO BOMB OUT AS IT LIFTS RAPIDLY TO A
POSITION OFF CAPE COD IN MASSACHUSETTS BY NIGHTFALL. TRAILING FROM
THE LOW WILL BE A STRONG COLD FRONT THAT LOOKS TO BE INTO THE
ATLANTIC BY 12Z THAT TAKES THE DEEP MOISTURE AXIS WITH IT. BUT UNTIL
THE PASSAGE OF THE SHORT WAVE ALOFT WE HAVE HELD ONTO SLIGHT
CHANCE/CHANCE POPS IN GA AND CHANCE/LIKELY POPS FOR A COUPLE HOURS
IN THE MORNING...BEFORE COVERAGE DIMINISHES QUICKLY FROM SW TO NE BY
LATE MORNING AND MIDDAY. LARGE AND STEADY ISALLOBARIC PRESSURE RISES
OF AS MUCH AS 2-3MB/3 HOURS THROUGH 18Z WILL COINCIDE WITH THE BEST
COLD ADVECTION. FOR THE REST OF THE DAY COLD ADVECTION WANES...BUT
DEEP MIXING AND A TIGHT GRADIENT WILL PERSIST. THESE FACTORS SUPPORT
A BREEZY TO WINDY DAY...BUT PROBABLY NOT QUITE TO THE CRITERIA FOR A
WIND ADVISORY WHICH OCCURS WHEN WE HAVE 30 MPH SUSTAINED WINDS FOR
ONE HOUR AND/OR GUSTS OF 40 MPH OR MORE FOR ANY DURATION. CLOUD
COVER WILL ERODE FOR THE LATE MORNING/AFTERNOON FROM WEST/SW TO
EAST/NE AND ONCE INSOLATION DOES DEVELOP IT WILL SPEND MUCH OF ITS
ENERGY EVAPORATING THE PREVIOUS RAINS. THAT ALONG WITH COLD ADVECTION
WILL ACTUALLY PROVIDE THE AREA WITH A ATYPICAL DIURNAL TEMP CURVE AS
TEMPS DROP SEVERAL DEGREES IN THE MORNING BEHIND THE COLD
FRONT...THEN ONLY RISE A FEW DEGREES IN THE AFTERNOON. AS A
RESULT... MUCH OF THE DAYLIGHT HOURS WILL ONLY HAVE TEMPS IN THE
50S.
LAKE WINDS...ANALYSIS OF SOUNDINGS AND GEOSTROPHIC WINDS INDICATE
THAT WHILE WE WILL LIKELY EXPERIENCE WIND GUSTS OF 25 KT OR GREATER
OVER AND NEAR THE SHORELINE OF LAKE MOULTRIE ON SATURDAY...WINDS
WON/T MIX AS MUCH OVER THE BULK OF THE LAKE. AFTER COORDINATION WITH
WFO CAE WE HAVE CHOSEN NOT TO HOIST A LAKE WIND ADVISORY AT THIS
TIME. HOWEVER...WITH STEADY PRESSURE RISES INTO THE AFTERNOON AND
THEN A TIGHT GRADIENT...AN ADVISORY MAY YET BE REQUIRED AT A LATER
TIME.
SATURDAY NIGHT...HIGH PRESSURE FROM THE GULF WILL POKE INTO THE
FORECAST ZONES BEHIND THE LARGE AND INTENSE CYCLONIC CIRCULATION IN
WAKE OF THE STORM SYSTEM OFF NEW ENGLAND. WINDS WILL SHUT OFF
CONSIDERABLY AT SUNSET...AND ALTHOUGH MOST LOCALES WON/T GO
COMPLETELY CALM THERE IS ENOUGH RADIATIONAL COOLING UNDER CLEAR
SKIES TO SUPPORT LOWS IN THE MID AND UPPER 30S FOR ALL BUT THE
SLIGHTLY WARMER IMMEDIATE COAST.
SUNDAY...QUIET CONDITIONS WILL PREVAIL UNDER THE INFLUENCE OF
QUASI-ZONAL FLOW ALOFT AND WEAK RIDGING INITIALLY THAT GIVES WAY TO
A SLIGHTLY MORE CYCLONIC FLOW LATE IN ADVANCE OF LOW PRESSURE IN THE
OHIO VALLEY. THIS LOW WILL BE ORGANIZING IN RESPONSE TO AN
IMPRESSIVE SHORT WAVE DIGGING SE THROUGH THE OHIO...TENNESSEE AND
MISSISSIPPI VALLEYS. CONSIDERABLE SUNSHINE...DOWNSLOPE TRAJECTORIES
OFF THE APPALACHIANS AND THE DRY AIR MASS WILL ALLOW TEMPS TO
MODERATE INTO THE UPPER 50S-LOWER 60S. A RESULTANT SEA BREEZE
HOWEVER HOLDS COASTAL SC COMMUNITIES IN THE MID 50S.
SUNDAY NIGHT AND MONDAY...A VIGOROUS SHORT WAVE WILL SWING RAPIDLY
INTO THE SE SUNDAY NIGHT THEN INTO THE ATLANTIC MONDAY. CO-LOCATED
AT THE SURFACE WE FIND A CLIPPER-TYPE LOW THAT MOVES THROUGH
SOUTHERN VIRGINIA/NORTHERN NC AT NIGHT AND STARTS TO DEEPEN AS IT.
TRAILING FROM THE LOW WILL BE TWO COLD FRONTS...ONE THAT PULLS
THROUGH HERE AFTER MIDNIGHT SUNDAY NIGHT...AND THE SECOND THAT
APPROACHES BY LATE MONDAY. WITH PWATS LESS THAN 1/2 INCH...LITTLE TO
NO CONVERGENCE NOR INSTABILITY THE RISK FOR ANY SHOWERS IS REMOTE
WITH THE COLD FRONTS. WE CAN/T ENTIRELY RULE OUT SOMETHING GIVEN THE
STRONG IMPULSE ALOFT AND STEEP MID LEVEL LAPSE RATES...BUT WE HAVE
MAINTAINED THE IDEA OF A DRY FORECAST. COLD ADVECTION BEHIND THE
FIRST FRONT WILL DROP THE 850 0C ISOTHERM INTO OUR NORTHERN ZONES
LATE SUNDAY NIGHT/EARLY MONDAY. BUT THIS IS NEGATED BY PLENTY OF
INSOLATION MONDAY AND DOWNSLOPE OFF THE MOUNTAINS. THUS TEMPS WILL
ACTUALLY BE NEAR OR EVEN A TAD ABOVE NORMAL. MONDAY WILL BE ANOTHER
BREEZY DAY...MAINLY IN THE 15-20 MPH AND GUSTY RANGE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A DRY COLD FRONT IS EXPECTED TO SHIFT THROUGH THE REGION MONDAY
NIGHT...SETTING UP COOL AND DRY CONDITIONS THROUGH AT LEAST MIDWEEK
WHILE SFC HIGH PRESSURE BUILDS OVER THE SOUTHEAST AND A LARGE MID
LVL TROUGH OF LOW PRESSURE HOLDS OVER THE EASTERN CONUS. IN
GENERAL...HIGH TEMPS WILL RANGE IN THE LOW/MID 50S TUESDAY AND
WEDNESDAY AS THE AREA REMAINS ALONG THE SOUTHERN EDGE OF TROUGH
CENTERED TO OUR NORTH. OVERNIGHT LOWS WILL RANGE IN THE LOW/MID 30S.
TEMPS SHOULD THEN SLOWLY MODIFY OVER THE SOUTHEAST LATE WEEK AS THE
MID/UPPER LVL TROUGH OF LOW PRESSURE BEGINS TO SLIDE OFF THE
ATLANTIC COAST...BUT TEMPS SHOULD REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
KCHS...MAINLY MVFR CONDITIONS THIS AFTERNOON...DROPPING TO IFR
CEILINGS AND OCCASIONALLY VSBYS IN STRATUS AND RAIN. THE HEAVIEST
RAIN IS EXPECTED LATE THIS AFTERNOON THROUGH MID TO LATE EVENING.
COLD FRONT WILL PUSH THROUGH LATE TONIGHT WITH IMPROVING
CONDITIONS BUT INCREASING WINDS OUT OF THE WEST.
KSAV...MAINLY IFR CEILINGS AND/OR VSBYS THROUGH TONIGHT IN RAIN
AND LOW STRATUS THOUGH PERIODS OF LIFR CEILINGS POSSIBLE AS WELL.
THUS FAR THE GUIDANCE HAS BEEN WAY TOO PESSIMISTIC ON FLIGHT
CATEGORY AT BOTH TERMINALS...THOUGH THINGS NOW APPEAR TO BE
CATCHING UP. CONDITIONS IMPROVE AFTER SUNRISE SATURDAY AS CEILINGS
LIFT TO MVFR...RAIN SHIFTS AWAY AND WINDS BECOME GUSTY OUT OF THE
WEST.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL RETURN TO BOTH
TERMINALS SATURDAY AFTERNOON...THEN PERSIST THROUGH WEDNESDAY OF
NEXT WEEK. HOWEVER...WE WILL EXPERIENCE GUSTY WEST-NW WINDS SATURDAY
AFTERNOON UNTIL A LOW PRESSURE SYSTEM SHIFTS FURTHER NORTHEAST AND
AWAY FROM THE AREA AND WINDS DROP OFF BY SUNSET. GUSTY NW WINDS TO
OCCUR AGAIN MONDAY BEHIND A COLD FRONT.
&&
.MARINE...
THE COASTAL TROUGH HAS CONTINUED TO STRENGTHEN THIS AFTERNOON
THOUGH WE ARE FINALLY SEEING SIGNS OF IT SHIFTING INLAND WITH THE
APPROACHING LOW-LEVEL SOUTHERLY JET. BY EARLY EVENING WE EXPECT
WINDS TO SHIFT TO THE SOUTH AND INCREASE DRASTICALLY. ONGOING GALE
WARNING FOR OFFSHORE GA WATERS IS STILL ON TRACK. GIVEN THE WARM
ADVECTION REGIME AND THE COOL WATERS NEAR SHORE...EVEN WITH ROBUST
GEOSTROPHIC WINDS WE DO NOT ANTICIPATE GALE CONDITIONS OUTSIDE OF
THE CURRENT WARNING. HOWEVER...SOLID SMALL CRAFT ADVISORY
CONDITIONS WILL DEVELOP ACROSS THE NEARSHORE WATERS AND CHARLESTON
HARBOR THIS EVENING AND CONTINUE OVERNIGHT.
SATURDAY...DANGEROUS MARINE CONDITIONS WILL BE ONGOING AND
PERSIST THROUGH THE DAY IN RESPONSE TO INTENSIFYING LOW PRESSURE
OFF THE DELMARVA. STEADY ISALLOBARIC PRESSURE RISES INTO THE
AFTERNOON WILL COINCIDE WITH THE BEST COLD ADVECTION. THIS WILL
EASILY SUPPORT SMALL CRAFT ADVISORIES FOR WEST/NW WINDS OF 20-30
KT ACROSS THE 0-20 NM WATERS AND CHARLESTON HARBOR. ACROSS THE
OUTER GA WATERS WE HAVE CONTINUED THE GALE WARNING UNTIL 18Z...BUT
ONCE THAT COMES DOWN WE/LL NEED TO TRANSITION OVER TO A SMALL
CRAFT ADVISORY.
SATURDAY NIGHT...THERE IS ENOUGH IMPROVEMENT IN WINDS/SEAS AS HIGH
PRESSURE BUILDS FROM THE WEST AND THE GRADIENT RELAXES
SOME...ALLOWING FOR ALL ADVISORIES TO COME DOWN EXCEPT FOR AMZ374
WHERE WINDS ARE STILL AS HIGH AS 25 KT AND SEAS OF 6 OR 7 FT.
SUNDAY...THIS LOOKS TO BE THE BETTER OF THE TWO WEEKEND
DAYS...ALTHOUGH WINDS AND SEAS WILL STILL BE SOMEWHAT ELEVATED
BETWEEN A HIGH PRESSURE RIDGE FROM THE GULF ACROSS FLORIDA AND LOW
PRESSURE IN THE OHIO VALLEY. WEST AND SW WINDS WILL BE CAPPED AT 15
OR MAYBE 20 KT AND SEAS 5 FT OR LESS.
SUNDAY NIGHT AND MONDAY...ANY IMPROVEMENT IN MARINE CONDITIONS WILL
HAVE ONLY BEEN TEMPORARY AS A CLIPPER-TYPE LOW MOVES OFF THE
MID-ATLANTIC COAST AND A TRAILING COLD FRONT SWINGS THROUGH LATE
SUNDAY NIGHT. THE PRESSURE PATTERN WILL TIGHTEN AGAIN AROUND THE LOW
TO THE NORTH SUNDAY NIGHT BEFORE IT PULLS OFF TO THE EAST/NE MONDAY.
WINDS AND SEAS WILL AGAIN RISE AND ADDITIONAL SMALL CRAFT ADVISORIES
SEEM LIKELY.
TUESDAY THROUGH WEDNESDAY...FOR THE MOMENT IT LOOKS LIKE WE/LL BE
BELOW ANY ADVISORY CONDITIONS BETWEEN LOW PRESSURE IN THE WESTERN
ATLANTIC AND HIGH PRESSURE DEVELOPING OUT OF THE NORTHERN PLAINS AND
OHIO VALLEY.
&&
.TIDES/COASTAL FLOODING...
DO NOT EXPECT THIS EVENING/S HIGH TIDE TO REACH ADVISORY CRITERIA
AT CHARLESTON NOR SAVANNAH AS THE ANOMALY WOULD NEED TO BE MORE
THAN 1.3 FEET. WINDS BECOMING SOUTHERLY THIS EVENING SHOULD REDUCE
THE SURGE CONSIDERABLY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR AMZ330-350-
352-354.
GALE WARNING UNTIL 1 PM EST SATURDAY FOR AMZ374.
&&
$$
NEAR TERM...JRL
SHORT TERM...33
LONG TERM...DPB
AVIATION...33/JRL
MARINE...33/JRL
TIDES/COASTAL FLOODING...JRL
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
248 PM EST FRI JAN 23 2015
.SYNOPSIS...
RAIN WILL DOMINATE THE REGION AS THE LOW MOVES NORTHEASTWARD AND
ACROSS THE LOW COUNTRY THIS EVENING. THE LOW WILL REACH THE OUTER
BANKS TONIGHT AND FURTHER AWAY FROM THE AREA ON SATURDAY. WEAK
HIGH PRESSURE WILL CONTROL THE AREA SUNDAY WITH ANOTHER FAST
MOVING SYSTEM CROSSING THE REGION SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A SOUTHERN STREAM UPPER TROUGH OVER THE SOUTH CENTRAL US WILL
SWING TOWARD THE CAROLINAS TONIGHT. LOW PRESSURE CURRENTLY ALONG
THE FLORIDA PANHANDLE WILL CONTINUE MOVING NORTHEASTWARD ACROSS
SOUTHEAST GEORGIA AND TOWARD THE LOW COUNTRY OF SOUTH CAROLINA.
STILL A BIT OF UNCERTAINTY IN THE EXACT TRACK OF THE LOW WITH THE
NAM A BIT FURTHER EAST THAN THE GFS. THE WPC PREFERRED TRACK IS
CLOSER TO THE GFS SOLUTION SHOWING IT TRACKING THROUGH THE EASTERN
EDGE OF THE FORECAST AREA. QPF AMOUNTS SO FAR TODAY HAVE BEEN LESS
THAN MODEL GUIDANCE LIKELY DUE TO MOISTURE GETTING CUT OFF WITH
CONVECTION ALONG THE GULF. MODELS SHOW THE HIGHEST PRECIPITABLE
WATER VALUES DURING THE 21Z TO 06Z TIME FRAME AS THE LOW NEARS THE
AREA. INCREASED CONVERGENCE IN THE VICINITY OF THE LOW AND BEST
MOISTURE SUPPORT HIGHEST POPS DURING THIS TIME FRAME. RAINFALL
WILL BEGIN TO DIMINISH DURING THE EARLY MORNING AS THE LOW CENTER
MOVES WELL NORTHEAST OF THE AREA. THE HRRR AND NSSL WRF SIMULATED
REFLECTIVITY MODELS SHOW MOST OF THE PRECIPITATION SHIFTING
NORTHEAST OF THE AREA AFTER 03Z. TEMPERATURES ARE FORECAST TO RISE
IN THE FAR EASTERN MIDLANDS AS THE WARM FRONT CROSSES THE AREA.
IN THE NORTHERN AND WESTERN MIDLANDS...TEMPERATURES FORECAST TO
DROP ONLY A FEW DEGREES OVERNIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
SATURDAY...LOW PRESSURE WILL CONTINUE TRACKING NORTH-NORTHEASTWARD ON
SATURDAY WITH MOISTURE DECREASING ACROSS THE AREA. MODELS DO SHOW
SOME WRAP-AROUND MOISTURE SATURDAY MORNING SO HAVE SHOWN POPS
TAPERING OFF THROUGH THE MORNING FROM SOUTHWEST TO NORTHEAST. MOST
OF THE RAIN SHOULD BE OUT OF THE AREA BY SATURDAY AFTERNOON AS
HIGH PRESSURE RIDGES INTO THE AREA FROM THE WESTERN GULF. CLOUD
COVER WILL DECREASE AS DRIER AIR ADVECTS INTO THE AREA. EXPECT
SLIGHTLY BELOW NORMAL HIGH TEMPERATURES IN THE LOW TO MID 50S.
MAINLY CLEAR SKIES OVERNIGHT WILL ALLOW FOR DECENT RADIATIONAL
COOLING ALTHOUGH LIGHT WINDS ARE FORECAST SO DO NOT EXPECT IDEAL
CONDITIONS. FORECASTING LOWS IN THE LOW TO MID 30S.
SUNDAY...HIGH PRESSURE WILL MOVE THROUGH THE AREA SUNDAY AS A
STACKED LOW PRESSURE SYSTEM APPROACHES FROM THE WEST. THIS FAST
MOVING SYSTEM WILL SWING THROUGH SUNDAY NIGHT. THE BETTER
MOISTURE WILL REMAIN TO OUR NORTH...SO HAVE CONTINUED TO INDICATE
ONLY SLIGHT CHANCE POPS SUNDAY NIGHT IN THE NORTHERNMOST COUNTIES.
INCREASING CLOUDS ON SUNDAY WITH NEAR NORMAL HIGHS TOPPING OUT IN
THE MID TO UPPER 50S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NOT MUCH CHANGE IN THE THINKING FOR THE EXTENDED PERIODS AS MEDIUM
RANGE MODELS CONTINUE TO ADVERTISE A HIGHLY AMPLIFIED 500MB FLOW
PATTERN FEATURING A WESTERN RIDGE AND EASTERN TROUGH.
A LEAD SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW WILL PUSH
EASTWARD OFF THE MID-ATLANTIC COAST LEAVING THE FORECAST AREA WITHIN
A NORTHWESTERLY FLOW REGIME AND COLD ADVECTION. SKIES SHOULD BE
CLEARING THROUGH THE DAY AS DRIER AIR BUILDS INTO THE REGION WITH
HIGH PRESSURE. TEMPERATURES EXPECTED TO BE NEAR TO SLIGHTLY BELOW
NORMAL MONDAY WITH HIGHS GENERALLY IN THE MID 50S.
THE UPPER TROUGH AXIS WILL EXTEND FROM EASTERN CANADA DOWN TO THE
CAROLINAS BY TUESDAY MORNING AND ANOTHER FAST MOVING SHORTWAVE
TROUGH WILL ROTATE THOUGH THE BASE OF THE TROUGH BRINGING A DRY COLD
FRONT THROUGH THE AREA BY TUESDAY EVENING. LITTLE MOISTURE WILL BE
AVAILABLE FOR THE FRONT SO DRY WEATHER IS FORECAST. TEMPERATURES
WILL BE BELOW NORMAL TUE/WED WITH PERSISTENT NORTHERLY LOW LEVEL
FLOW AS A 1033MB SURFACE RIDGE BUILDS OVER THE OHIO VALLEY INTO THE
CAROLINAS MID WEEK. HIGHS GENERALLY EXPECTED IN THE 40S TO LOWER
50S WHILE OVERNIGHT LOWS FALL INTO THE 20S TO NEAR 30 DEGREES.
A FLATTENING UPPER RIDGE WILL SHIFT OVER THE FORECAST AREA ON
THURSDAY IN RESPONSE TO YET ANOTHER FAST MOVING SHORTWAVE TROUGH
MOVING THROUGH THE BROAD NORTHWESTERLY 500MB FLOW. TEMPERATURES
SHOULD REBOUND A BIT BACK TO NEAR NORMAL VALUES ON THURSDAY WITH A
WEAK AND DRY FRONT PUSHING THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY MORNING.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
WIDESPREAD RAIN CONTINUES TO OVERSPREAD THE TERMINALS AS
ISENTROPIC LIFT CONTINUES AHEAD OF AN APPROACHING LOW PRESSURE
SYSTEM. CIGS HAVE FALLEN TO MVFR CATEGORY AND ALL TERMINALS SHOULD
DROP TO IFR CIGS BETWEEN 19Z-22Z...WITH LOWER CONFIDENCE ON VSBYS
BUT WILL CONTINUE MVFR VSBYS IN RAIN THROUGHOUT THE AFTERNOON AND
EVENING.
MODEL TRENDS ARE SHOWING THE WIDESPREAD RAIN PUSHING OUT OF THE
AREA EARLIER...AFTER 03Z OR SO ALTHOUGH THE UPPER SYSTEM WILL
REMAIN TO THE WEST...SO WILL CONTINUE WITH SOME DRIZZLE OVERNIGHT
AND IFR/LIFR CIGS. AFTER THE SURFACE LOW PASSES DURING THE 04Z-06Z
TIME FRAME...NORTHEASTERLY WINDS AROUND 10 MPH WILL SHIFT TO THE
WEST AND INCREASE AS THE PRESSURE GRADIENT STRENGTHENS WITH THE
SURFACE LOW DEEPENING AS IT MOVES AWAY FROM THE REGION. WINDS WILL
PICK UP TO 10 TO 15 MPH WITH GUSTS TO 25-30 MPH AFTER 12Z-14Z.
HAVE CONTINUED THE MENTION OF LOW LEVEL WIND SHEAR THIS AFTERNOON
WITH STRONG WINDS JUST ABOVE THE STABLE BOUNDARY LAYER.
SOME IMPROVEMENT IN CIGS EXPECTED AFTER 15Z SATURDAY BUT WILL OPT
TO KEEP MVFR CIGS GOING THROUGH THE END OF THIS FORECAST.
EXTENDED AVIATION OUTLOOK...POSSIBLE RESTRICTIONS ON MONDAY AS
ANOTHER SYSTEM MOVES THROUGH THE REGION BUT CONFIDENCE IS LOW AT
THIS TIME.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
901 PM CST SAT JAN 24 2015
.UPDATE...
900 PM CST
EVENING UPDATE...
HAVE UPDATED GRIDS TO REFLECT MUCH LOWER SNOWFALL AMOUNTS ON SUNDAY
TO THE NORTH OF INTERSTATE 80 AND ALSO SLOWED ARRIVAL OF
PRECIPITATION MAINLY TO EARLY TO MID SUNDAY MORNING. RADAR...SURFACE
ANALYSIS AND SATELLITE TRENDS SUPPORT THE NEW 00Z GUIDANCE AND
LATEST HIGHER RESOLUTION GUIDANCE ROLLING IN DIGGING THE 500 MB WAVE
FARTHER SOUTHWEST AND ASSOCIATED SURFACE LOW FARTHER SOUTHWEST AND
THEN SOUTH OF THE CWA. NOW LOOKING AT GENERALLY AROUND A FEW TENTHS
TO UP TO AN INCH NORTH OF INTERSTATE 88...ONE TO TWO INCHES BETWEEN
I-88 AND I-80 AND ONE TO THREE INCHES SOUTH OF INTERSTATE 80. IF THE
FARTHER SOUTH TREND BECOMES MORE AGGRESSIVE AS THE SYSTEM APPROACHES
SUNDAY...THEN EVEN THESE AMOUNTS COULD END UP BEING TOO HIGH.
NAM/WRF AND OTHER HIGHER-RES GUIDANCE CONTINUES TO HINT AT LAKE
ENHANCEMENT DURING THE DAY SUNDAY INTO THE AFTERNOON INTO PARTS OF
NORTHEAST IL AND NW IN...BUT UNLESS FRICTIONAL CONVERGENCE CAN
ENHANCE RATES A BIT...THE THERMODYNAMICS AND INVERSION HEIGHTS ARE
VERY MARGINAL TO ACTUALLY ADD MUCH TO SNOW TOTALS.
REGARDING THE MIXED PRECIPITATION IN THE SOUTHERN CWA...THE
SOUTHWARD TREND AND DELAYED TIMING OF THE SYSTEM SHOULD ALLOW FOR
COLDER AIR TO BLEED SOUTHWARD AND SUPPRESS THE MIXING ZONE SOUTHWARD
FROM THE PREVIOUS FORECAST. ANY WINTRY MIX/RAIN SNOW MIX IN THE FAR
SOUTHERN CWA WILL LIKELY TRANSITION TO SNOW BY MID DAY/EARLY
AFTERNOON.
UPDATED ZONES WILL BE SENT SHORTLY.
RC/KREIN
&&
.SHORT TERM...
250 PM CST
THROUGH SUNDAY...
MAIN FORECAST CONCERN WILL BE PASSAGE OF A CLIPPER SYSTEM ACROSS THE
MIDWEST BRINGING ACCUMULATING SNOWFALL AND FOR SOME AREAS A WINTRY
MIX OF PRECIPITATION. CLOUD COVER WILL CONTINUE TO INCREASE THE
REMAINDER OF THE TODAY AS THE LOW DIVES ACROSS THE DAKOTAS INTO
MINNESOTA. MODELS ARE IN DECENT AGREEMENT TRACKING THE SURFACE LOW
ACROSS FAR NE MO LATE TONIGHT INTO DOWNSTATE IL BY SUNDAY AFTERNOON.
1000MB-700MB LAYER MAX WETBULBS ARE UP TO 2C SOUTH OF THE I-80
CORRIDOR THROUGH LATE MORNING/EARLY AFTERNOON SUNDAY...THEN START TO
FALL QUICKLY FROM THE NORTH THROUGH THE AFTERNOON HOURS. WITH THAT
IN MIND...THINK THAT PRECIP WILL BEGIN AS PRIMARILY SNOW NORTH OF
THE I-80 CORRIDOR WITH RAIN/SLEET TO THE SOUTH...EVENTUALLY CHANGING
OVER TO ALL SNOW. MODELS IN GENERAL HAVE THE AXIS OF HIGHEST QPF
SOUTH OF I-80...BUT WITH WARMER TEMPERATURES...IT APPEARS THE
HIGHEST SNOWFALL MAY OCCUR A LITTLE FARTHER NORTH. DID BUMP UP SNOW
TOTALS ACROSS PORTIONS OF THE CHICAGO METRO WHERE MODELS CONTINUE TO
ADVERTISE AN INCREASE IN THE LOW LEVEL LAPSE RATES AS WINDS TURN NE
OFF LAKE MICHIGAN WITH LAKE ENHANCEMENT APPEARING AT LEAST POSSIBLE.
NAM AND REGIONAL GEM GUIDANCE BOTH SHOW A SLIGHT MAX IN THE QPF
VALUES OVER THE AREA AND HAVE BEEN CONSISTENTLY ADVERTISING A BUMP IN
THE LOW LEVEL OMEGA STARTING LATE MORNING INTO THE AFTERNOON.
FORECAST SNOW TOTALS FOR THIS EVENT WILL BE 1-3 INCHES WEST OF A
WAUKEGAN TO STREATOR LINE...AND 2-4 INCHES EAST. WILL HAVE TO
MONITOR THE MESOSCALE BANDING THREAT FOR SOME LOCALLY HIGHER
AMOUNTS. NAM GUIDANCE IN PARTICULAR WAS HINTING AT AN AREA OF LOW
LEVEL FGEN DEVELOPING FOR EAST CENTRAL IL AND NORTHWEST
INDIANA...BUT LAPSE RATES UPSTAIRS ARENT OVERLY IMPRESSIVE IN THE
LATEST MODELS RUNS. ALSO SURFACE LOW SLOWLY FILLING AS IT MOVES
TOWARDS THE OHIO VALLEY WILL ALSO BE A LIMITING FACTOR. WILL ISSUE
AN UPDATED SPS THIS AFTERNOON FOR THE SNOWFALL. AS MENTIONED...STILL
CANNOT RULE OUT SOME LOCALLY HIGHER AMOUNTS THAT MIGHT REQUIRE AN
ADVISORY HOWEVER DONT HAVE MUCH CONFIDENCE WHERE OR EVEN IF THIS
WOULD OCCUR.
WINDS WILL START TO RAMP UP FROM EARLY MORNING ON OUT OF THE
NORTHEAST AS A TIGHT GRADIENT SWEEPS ACROSS THE REGION ON THE BACK
SIDE OF THE LOW. NORTHEAST WINDS ARE EXPECTED TO GUST 30-35 MPH AT
TIMES ACROSS THE AREA. THESE MODERATELY STRONG NORTHEAST WINDS OVER
LAKE MICHIGAN WILL DRIVE 8-11 FOOT WAVES INTO THE NEARSHORE WATERS
AND SOME OF THESE WAVES MAY RESULT IN SOME MINOR LAKE SHORE FLOODING
TO EXPOSED AREAS. IN ADDITION...BLOWING SNOW MAY BECOME A PROBLEM
ESPECIALLY IN OPEN AREAS. WETTER THAN AVERAGE SNOW...PARTICULARLY
SOUTH OF I-80 MAY HELP LIMIT THE BLOWING SNOW SOME.
DEUBELBEISS
&&
.LONG TERM...
SUNDAY NIGHT THROUGH SATURDAY...
250 PM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
AFTERNOON INTO MONDAY NIGHT AND THEN THE POTENTIAL FOR A WINTRY
MIX WEDNESDAY NIGHT.
LIGHT SNOW WILL BE ENDING ACROSS THE SOUTHEAST CWA SUNDAY EVENING
AS NORTHEAST WINDS STEADILY DIMINISH SUNDAY EVENING. LAKE EFFECT
CLOUDS AND PERHAPS A FEW FLURRIES ARE POSSIBLE SUNDAY EVENING. LOWS
BY MONDAY MORNING WILL DIP INTO THE TEENS MOST LOCATIONS BUT AS A
WEAK RIDGE PASSES ACROSS THE AREA AND WINDS BECOME LIGHT OR CALM...
LOWS COULD BE SEVERAL DEGREES COLDER DEPENDING ON CLOUD COVER.
ANOTHER WEAK CLIPPER SYSTEM MOVES SOUTHEAST ACROSS THE WESTERN
LAKES MONDAY AFTERNOON INTO MONDAY NIGHT AS IT SLOWLY BEGINS TO
WEAKEN. MODELS VARY SOME ON TIMING AND PRECIP ARRIVAL. A CONSENSUS
WOULD HAVE THE ARRIVAL DURING MONDAY AFTERNOON. INITIALLY THE
SATURATION IS DEEP ENOUGH THAT PRECIP SHOULD BEGIN AS LIGHT SNOW.
BUT INTO THE EVENING...MID LEVELS BEGIN TO DRY OUT SOME AND PRECIP
COULD TRANSITION MORE TO A LIGHT SNOW MIXED WITH OR JUST FREEZING
DRIZZLE. FAIRLY LOW CONFIDENCE AT THIS POINT...SO MAINTAINED JUST
LIGHT SNOW FOR THE ENTIRE DURATION FOR NOW.
PROGRESSIVE PATTERN BRINGS ANOTHER RIDGE OF HIGH PRESSURE ACROSS
THE REGION TUESDAY NIGHT INTO WEDNESDAY AND THEN ANOTHER STORM
SYSTEM WEDNESDAY NIGHT INTO THURSDAY MORNING. MODELS CURRENTLY IN
DECENT AGREEMENT WITH THE TRACK OF THIS LOW GENERALLY RIGHT ACROSS
THE CWA EARLY THURSDAY MORNING. WITH THIS TRACK...TEMPS LIKELY TO
REMAIN FAIRLY STEADY IN THE LOWER/MID 30S WEDNESDAY NIGHT AND
THERMAL PROFILES WOULD SUGGEST PRECIP WOULD BE MAINLY RAIN OR
PERHAPS FREEZING RAIN...IF SURFACE TEMPS REMAINED BELOW FREEZING.
AND ALSO COULD BE SOME SNOW IF THE LOW WERE TO SPEED UP AND/OR
TRACK FURTHER SOUTH. THUS DID NOT GET TOO SPECIFIC WITH PRECIP
TYPE WEDNESDAY NIGHT INTO THURSDAY BUT A WINTRY MIX IS POSSIBLE.
CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* MVFR OR IFR CIGS LIKELY MOVE BACK IN LATER TONIGHT CONTINUE
THROUGH SUNDAY EVENING
* SNOW DEVELOPS EARLY SUNDAY MORNING THE TAPERS OFF SUNDAY
AFTERNOON...IFR VSBY LIKELY WITH PERIODIC LIFR POSSIBLE
* STRONG NE WINDS DEVELOP SUNDAY MORNING CONTINUE INTO EARLY
SUNDAY EVENING...GUSTS TO 30KT AT TIMES SUNDAY LATE MORNING AND
AFTERNOON
IZZI
//DISCUSSION...UPDATED 00Z...
LOW END MVFR/SPOTTY IFR CIGS SHOULD CLEAR EASTERN TERMINALS SOON
WITH IT LOOKING MORE LIKELY THAT VFR CONDITIONS WILL BE THE RULE
THIS EVENING. OVERNIGHT WINDS WILL TURN NORTHEAST AND SHOULD ALLOW
LOW END MVFR/HIGH END IFR CIGS TO SLOSH BACK SOUTH INTO THE AREA
OVERNIGHT WITH THE WIND SHIFT. SNOW IS STILL EXPECTED TO DEVELOP
AROUND OR JUST PRIOR TO SUNRISE AND CONTINUE THROUGH SUNDAY
MORNING BEFORE TAPERING OFF TO LIGHT NON-ACCUMULATING SNOW OR
FLURRIES DURING THE EARLY/MID AFTERNOON. AS SNOW ENDS CIGS SHOULD
LIFT AND COULD EVEN SCATTER OUT SUNDAY EVENING AS THE SYSTEM PULLS
QUICKLY AWAY FROM THE REGION. OTHER ISSUE IS EXPECTED TO BE THE
STRONG NORTHEAST WINDS THAT WILL DEVELOP SUNDAY MORNING AND
CONTINUE INTO THE AFTERNOON WITH GUSTS OF 25-30KT LOOKING QUITE
LIKELY FROM MID MORNING THROUGH LATE AFTERNOON SUNDAY.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN GENERAL CIG TRENDS THROUGH THE PERIOD BUT
LOWER CONFIDENCE ON PRECISE TIMING OF CATEGORY CHANGES
* MEDIUM-HIGH CONFIDENCE IN WINDS
* MEDIUM CONFIDENCE IN SNOW AND RELATED VSBY TRENDS IN TAFS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SLIGHT CHANCE -SN IN THE AFTERNOON. MVFR POSSIBLE.
TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MAINLY VFR DURING THE DAY THEN CHANCE OF -RASN AND
MVFR/IFR AT NIGHT.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF MVFR CIGS.
IZZI
&&
.MARINE...
127 PM CST
A COLD FRONT WILL BEGIN TO SHIFT SOUTHWARD DOWN LAKE MICHIGAN LATE
THIS AFTERNOON...WITH WINDS EXPECTED TO PICK UP OUT OF THE NORTH
INTO TONIGHT. WINDS OVER THE LAKE WILL THEN CONTINUE TO INCREASE
INTO SUNDAY AS A QUICK MOVING CLIPPER SYSTEM TRACKS SOUTHEASTWARD
ACROSS SOUTHERN ILLINOIS. THIS WILL RESULT IN NORTHEASTERLY WINDS UP
TO 30 KT BY EARLY SUNDAY MORNING ACROSS MOST OF THE LAKE...WITH THE
STRONGEST WINDS EXPECTED ACROSS THE SOUTHERN END OF THE LAKE...WHERE
A FEW GALE FORCE GUSTS TO 35 KT ARE POSSIBLE ON SUNDAY. THIS WILL
RESULT IN WAVES UP TO 10 FEET INTO THE NORTHEAST ILLINOIS SHORES
THROUGH SUNDAY EVENING. THE WINDS WILL QUICKLY ABATE ACROSS THE LAKE
SUNDAY NIGHT AS THE LOW SHIFTS TOWARDS THE EASTERN SEABOARD.
ANOTHER WEAKENING LOW WILL SHIFT SOUTHWARD OVER OR JUST WEST OF THE
LAKE LATE MONDAY AND MONDAY NIGHT. THIS WILL RESULT IN A PERIOD OF
LIGHT SOUTHERLY WINDS OVER THE LAKE DURING THIS PERIOD. LATER IN THE
WEEK ANOTHER LOW IS EXPECTED TO IMPACT THE GREAT LAKES REGION. THIS
SYSTEM STILL HAS THE POTENTIAL TO PRODUCE A PERIOD OF STRONG
SOUTHERLY WINDS WEDNESDAY NIGHT...FOLLOWED BY STRONG NORTHERLY WINDS
THURSDAY INTO FRIDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 AM SUNDAY TO 9 AM MONDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
846 PM CST Sat Jan 24 2015
.UPDATE...
ISSUED AT 846 PM CST SAT JAN 24 2015
Overnite forecast generally on track. 18z models and HRRR indicate
that low-level thermal profile may be conducive for some sleet to
mix with rain prior to 12z in the far NW. Will add wording for
that potential as far east as Peoria.
Still plenty of uncertainty in low-level temperature forecast for
late tonight and Sunday with most models indicate temperatures
near or possibly just above freezing at the surface and warmer
temps around 925 mb through the morning then rapid cooling behind
the expected cliper system during the afternoon and a changeover.
The trend of the solution envelope has also shifted south over the
past few days which if it continues will bring CAA into the
northern counties faster. Still appears that accumulations of an
1"-3" still possible mainly northeast of I-74 with the best
chances of accumulation occuring on elevated and grassy surfaces.
&&
.SHORT TERM...(Tonight)
ISSUED AT 236 PM CST SAT JAN 24 2015
Abundant sunshine occurring across the forecast area this afternoon,
which has allowed temperatures to warm well into the 40s, with some
50 degree readings about to occur in west central Illinois. The
leading edge of the high clouds from our incoming storm system are
about to cross the Mississippi River, and should become more
widespread over our area toward sunset.
Latest surface map shows the low center in central North Dakota. The
12Z models have trended a bit south again with the track, but are in
general agreement with a position in the Quincy area by sunrise
Sunday, and associated warm front extending east across the northern
CWA. With the CWA largely in the warm sector overnight, have shown
only a couple degrees of temperature fall tonight with the entire
area remaining well above freezing. Have updated the alignment and
timing of the PoP`s to focus on the period after midnight, and also
increase them from the west. Higher resolution models start
spreading precipitation in from the west after about 3 am, which
soundings show as rain, although a bit of sleet is hinted at across
the northwest CWA, with a dry wedge between 925 and 850 mb.
&&
.LONG TERM...(Sunday through Saturday)
ISSUED AT 236 PM CST SAT JAN 24 2015
After several days of significant spread and large north/south
swings in the storm track with Sunday`s clipper system, the models
have finally come into better agreement. The current consensus is
kind of a middle ground of the north/south extremes of the past few
days, although it leans more toward the southern tracks that had
been advertised. A more southern track is preferred considering how
much digging the clipper wave still appears to be doing on water
vapor imagery as it is diving into the northern Rockies/Plains.
Would not be surprised to see the ultimate track to be a little
south of the current model consensus, a track which result in an
associated shift of the main snowfall track.
The surface low center should be near the extreme tip of
west-central Illinois at 12Z Sunday, and will quickly race to the
southern tip of Ohio by 06Z Monday. The bulk of the precipitation
with this system should occur during the daylight hours Sunday as a
quick shot of modest isentropic ascent ahead of the wave, and jet
forcing/DPVA as the upper trof axis, swing through.
Measurable precipitation now appears to be a given areawide with
this system, and have boosted PoPs to Categorical (80%+) on Sunday.
The main question is rain versus snow, and how much snow will
accumulate. Temperatures to start the day across most if not all of
the forecast area will be too warm for snow to reach the ground
thanks to the southerly flow ahead of the clipper. Forecast
soundings suggest the low level thermal profile will steadily become
cool enough for a rain to snow transition from northwest to
southeast during the day as cold air wraps in on the north side of
the surface low. The change over should occur around Galesburg near
sunrise, along a Springfield to Champaign line around midday, and
south of I-70 by shortly after sunset. The current track and speed
of change over to snow supports 1-3 inch accumulations along and
north of the I-74 corridor, with an inch or less south of there. Any
lingering snow will quickly come to an end Sunday evening as the
clipper races south/east of the area.
Another wave, much weaker than the first one, will pass north of the
forecast area on Monday. Have started to back down from the already
low snow chances we had over northern portions of the forecast area
with this wave. The lead clipper is expected to develop into a major
east coast storm after it leaves the area, and Monday`s wave is
essentially shearing out into the much stronger system.
A stronger wave coming off the Pacific is expected to move through
the Midwest by Wednesday night and Thursday. At this point, this
system appears warm enough to be mainly a rain producer. Another
system may arrive to start next weekend, but model agreement in the
details is pretty low at this time.
Temperatures through the next week should be at or above normal. The
coolest readings are likely Monday/Tuesday behind the main clipper,
and again Friday/Saturday behind the midweek system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 512 PM CST SAT JAN 24 2015
cliper system continues to dig through the northern plains this
afternoon. Model trends have been to shift the surface track of
the waves surface reflection further south. Current indications
are that a KUIN-KSDF track is setting up for the 12z-00z perios
tomorrow. Given trends of last few runs and the current track of
the wave in water vapor imagery, would not be at all surprised if
track doesn`t end up being even further south. Realitively warm
conditions ahead of the system will give way to rapid CAA behind
the low indicating a change over from a mix of precip to snow by
late morning for KPIA and KBMI, and Midday at KCMI. Closer to the
low track KSPI and KDEC will likely start with a warmer thermal
profile and a period -RA at the precip onset with a changeover
midday to early afternoon. Forecasted model gradient during the
afternoon suggests winds increasing from northeast to 15-20kt and
higher gusts and will be reflected in I-74 sites. Speeds may be a
bit less closer to the low track.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barker
SHORT TERM...Geelhart
LONG TERM...Bak
AVIATION...Barker
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
305 PM CST FRI JAN 23 2015
.SHORT TERM...
TONIGHT AND SATURDAY...
305 PM...NO CONCERNS THROUGH SATURDAY EVENING. LOW CLOUDS CONTINUE
TO ERODE FROM THE NORTH AND THE SOUTHWEST THIS AFTERNOON. THIS
TREND WILL CONTINUE THIS EVENING AS THE BACK EDGE PUSHES EAST.
HOWEVER...AN EXTENSIVE BAND OF MID CLOUDS WILL SPREAD BACK ACROSS
THE AREA THIS EVENING AHEAD OF AN APPROACHING COLD FRONT. VERY
LIMITED MOISTURE WITH THIS FRONT AND NOT EXPECTING ANY PRECIP
THOUGH A SPRINKLE OR FLURRY CAN/T BE COMPLETED RULED OUT...BUT NO
MENTION IN THE FORECAST. CLOUD COVER HELPED HOLD HIGHS TODAY IN
THE LOWER/MID 30S AND WITH SOME PARTIAL CLEARING AT TIMES...EXPECT
LOWS TONIGHT TO DIP INTO THE MID/UPPER 20S...THOUGH SOME
UNCERTAINTY WITH APPROACHING MID CLOUDS AND THEN ANOTHER AREA OF
LOW CLOUDS OVER THE UPPER MIDWEST WHICH WILL BE SPREADING SOUTH
ACROSS THE AREA SATURDAY MORNING. IF THIS CLOUD COVER DOES BECOME
OVERCAST...HIGHS ON SATURDAY WILL LIKELY BE TEMPERED SOME AS
WELL...PERHAPS ONLY IN THE MID 30S. CMS
&&
.LONG TERM...
SATURDAY NIGHT THROUGH FRIDAY...
305 PM...MAIN FORECAST CONCERN IS ACCUMULATING SNOW LATE SATURDAY
NIGHT THROUGH SUNDAY AFTERNOON...WITH POSSIBLE LAKE EFFECT SNOW
SHOWERS SUNDAY NIGHT AND ANOTHER WEAKER CLIPPER SYSTEM MONDAY
NIGHT...FOLLOWED BY MODERATE/MILD TEMPS MIDDLE OF NEXT WEEK.
DECENT AGREEMENT WITH THE TRACK OF THE SURFACE LOW OF THE NEXT
CLIPPER SYSTEM SATURDAY NIGHT INTO SUNDAY WITH THE 12Z GFS A BIT
FURTHER SOUTHWEST OF THE REST OF THE MODELS...WHICH TRACK THE LOW
FROM ROUGHLY MLI TO IND SUNDAY MORNING. THERMAL PROFILES SUGGEST
PRECIP TYPE WILL BE ALL SNOW...BUT INITIALLY COULD BE SOME RAIN
MIXED IN ACROSS THE SOUTHERN CWA. IN ADDITION...SNOW/WATER RATIOS
COULD BE RATHER LOW TO START...YIELDING A WETTER SNOW. BUT AS THE
LOW TRACKS TO THE SOUTHEAST...COLDER AIR WILL SLOWLY SPREAD ACROSS
THE AREA WITH THE SNOW LIKELY BECOMING DRIER BY LATE MORNING AND
INTO THE AFTERNOON. THIS MAKES SNOWFALL AMOUNTS A BIT TRICKY...
ESPECIALLY IF THE TRACK OF THE LOW ENDS UP A LITTLE FURTHER SOUTH
AS THE GFS SUGGESTS...COLDER AIR WOULD ARRIVE SOONER. POSSIBLE
LAKE ENHANCEMENT WITH NORTHEAST FLOW ALSO ADDS TO THE UNCERTAINTY
REGARDING AMOUNTS. THEREFORE...DIDN/T MAKE ANY SIGNIFICANT
CHANGES TO THE GOING FORECAST WITH 2-4 INCHES NORTH OF A SQI/IKK
LINE...1-2 INCHES SOUTH OF THAT LINE. BUT AS IS ALWAYS THE
CASE...MINOR CHANGES IN THE TRACK COULD CAUSE LARGE CHANGES TO THE
FORECAST AS TRENDS EMERGE.
TEMPERATURES BEGIN TO FALL BY MID/LATE SUNDAY AFTERNOON ACROSS THE
NORTH. NORTHEASTERLY WINDS INCREASE WITH GUSTS TO 30 MPH AND
DEPENDING ON HOW DRY THE SNOW BECOMES...THERE COULD BE SOME
BLOWING SNOW BUT AGAIN...ITS TOO EARLY FOR SPECIFICS OR HOW MUCH
OF A PROBLEM THIS COULD BECOME.
THE NORTHEAST AND THEN NORTHERLY WINDS MAY ALLOW SOME LAKE EFFECT
SNOW SHOWERS TO DEVELOP SUNDAY EVENING ACROSS NORTHEAST IL AND
THEN INTO NORTHWEST INDIANA. BUT INVERSION HEIGHTS ARE RATHER
LOW...PERHAPS NO HIGHER THAN 4KFT AND WINDS BEGIN TO TURN BACK
EASTERLY BY MONDAY MORNING. THUS ANY LAKE EFFECT POTENTIAL LOOKS
MINIMAL.
ANOTHER CLIPPER QUICKLY DROPS SOUTHEAST ACROSS THE WESTERN LAKES
MONDAY AFTERNOON INTO MONDAY NIGHT...AS IT BEGINS TO WEAKEN. A
BAND OF LIGHT SNOW IS POSSIBLE WITH THIS FEATURE ESPECIALLY MONDAY
EVENING AND SOME AREAS MAY SEE AN INCH OR TWO DEPENDING ON WHERE
IT TRACKS. HAVE INCLUDED JUST LIGHT QPF AMOUNTS FOR NOW.
HIGH PRESSURE MOVES ACROSS THE AREA TUESDAY AND TUESDAY NIGHT AS
FLOW TURNS BACK SOUTH WEDNESDAY AND TEMPS MODIFY BACK INTO THE 30S
THOUGH WITH AN EXPECTED SNOWPACK BY THEN...LOW CONFIDENCE ON HOW
WARM TEMPS WILL BECOME. ANOTHER CLIPPER SYSTEM MOVES ACROSS THE
LAKES REGION WEDNESDAY NIGHT AND THURSDAY...WITH A CHANCE OF LIGHT
RAIN OR LIGHT SNOW WEDNESDAY NIGHT INTO THURSDAY MORNING. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* MVFR CIGS ARND 1500-1800FT AGL...SLOWLY LIFTING TO ARND 2KFT AGL
AFT 00Z.
* SOUTHWEST WINDS ARND 10-14KT WITH OCCASIONAL GUSTS TO 15-17KT
THRU 00Z.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS MORNING CONTINUED TO SHOW CONSIDERABLE CLOUD
COVER ACROSS THE REGION...WITH SOME CLEARING NOTED ACROSS EASTERN
IOWA. AS THE DAY HAS PROGRESSED SOME THINNING HAS BEGUN TO TAKE
PLACE ACROSS FAR NORTH/NORTHEAST ILLINOIS...AND MAY EVENTUALLY
MAKE IT INTO THE TAF SITES. AT THIS TIME THOUGH HAVE HELD ONTO THE
LOW CLOUDS THRU 00Z...WITH A SLOW IMPROVEMENT TOWARDS 2000-2500FT
AGL AFT 02Z. WINDS WILL CONTINUE TO BE SOUTHWESTERLY WITH SPEEDS
GENERALLY FROM 10-13KT. THRU THE AFTN ON OCCASION GUSTS MAY
OCCUR...AND NOT EXPECTED TO BE VERY FREQUENT WITH SPEEDS UP TO
17KT.
WITH A FRONTAL BOUNDARY SLIDING SOUTHEAST THIS EVENING...THERE IS
THE POTENTIAL FOR A FEW FLURRIES ACROSS ORD/MDW/DPA. ELSEWHERE
SHOULD BE TOO FAR REMOVED FROM THE BETTER MOISTURE TO SEE ANY
FLURRIES. THOUGH HAVE HELD ONTO A DRY FORECAST AS THIS TOO IS A
LOW CONFIDENCE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIGS REMAINING OVC THRU 23Z...MEDIUM
CONFIDENCE IN TIMING OF CIGS LIFTING HIGHER.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
122 PM CST
SOUTHWESTERLY WINDS WILL GRADUALLY WEAKEN TONIGHT...THEN A COLD
FRONT WILL SHIFT OVER THE LAKE ON SATURDAY AS THE PARENT SURFACE LOW
TRACKS ACROSS NORTHERN QUEBEC. THIS WILL SET UP A NORTHERLY FLOW
DOWN THE LAKE LATER SATURDAY. A FAST MOVING STOUT CLIPPER SYSTEM
WILL MOVE SOUTH OF THE LAKE ON SUNDAY MORNING...AND THIS LOOKS TO
SET THE STAGE FOR A PERIOD OF STRONG NORTHEASTERLY WINDS UP AROUND
30 KT OVER THE LAKE. THIS WILL LIKELY PRODUCE HIGH WAVES OVER 5 FEET
ACROSS MUCH OF SOUTHERN END OF LAKE MICHIGAN SUNDAY AND SUNDAY NIGHT.
FOLLOWING THIS SYSTEM...ANOTHER STORM SYSTEM IS EXPECTED TO IMPACT
THE GREAT LAKES REGION FOR THE MIDDLE TO END OF NEXT WEEK. IT
APPEARS THIS COULD PRODUCE SOUTHERLY GALE FORCE WINDS OVER MUCH OF
THE LAKE LATE WEDNESDAY AND WEDNESDAY NIGHT...FOLLOWED BY A PERIOD
OF POTENTIALLY GALE FORCE NORTHERLY WINDS THURSDAY AS THE SYSTEM
PASSES OVER THE EASTERN LAKES.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
248 PM CST Fri Jan 23 2015
.SHORT TERM...(Tonight)
ISSUED AT 247 PM CST FRI JAN 23 2015
Clearing line from the morning stratocumulus deck was unable to make
any further eastward progress, so the clouds decided to dissolve in
place instead. 2 pm visible satellite imagery showing most areas
west of I-55 now mostly sunny, with the clouds rapidly eroding on
the western flank of what`s left. The clear skies won`t last too
long though, as mid-level cloud deck ahead of the next frontal
boundary is already in southeast Iowa. The boundary itself is still
back across eastern Nebraska through the Minneapolis area, and will
be moving through our forecast area between midnight and sunrise.
However, no precipitation is expected with it. Lows across the
forecast area should fall into the upper 20s.
&&
.LONG TERM...(Saturday through Friday)
ISSUED AT 247 PM CST FRI JAN 23 2015
By and large, the forecast period will be dominated by a ridge
west/trof east pattern across North America, a pattern that has been
pretty common of late. The fast moving northwest upper-level flow
that has been over the forecast area has had numerous, mainly weak,
impulses embedded within it traveling over or in our vicinity. Most
of these waves lately, and those expected over the next several
days, have been too weak and/or moisture starved to produce much
precipitation locally. This trend should continue to be the case for
most of the days of this forecast. However, a more significant
clipper system still appears on track to impact the area late
Saturday night into Sunday night. This system is our primary
forecast concern today.
A weak upper/surface trof will move across the area later
tonight/early Saturday, but it is only expected to be accompanied by
an increase in cloud cover. This cloud cover is currently evident
upstream from the Great Lakes into the central Plains.
The timing of the main clipper is pretty well agreed upon, and has
been for a few days now, with the primary precipitation risk
occurring late Saturday night/early Sunday Morning into Sunday
afternoon. However, the track of the system continues to exhibit
considerable model spread, as well as run-to-run variability. The
overall model trend had been toward a more northerly track until
about 24 hours ago, but now the trend is back toward the south. The
northern track would have resulted in minimal precipitation risk for
the forecast area, with the bulk of it falling in the form of rain.
The more southern track, most pronounced in the latest run of the
GFS, would support more widespread precipitation locally, with at
least the northern portion of the forecast area in line for some
accumulating snow. Forecast confidence in the details with this
system remains low considering the variability/inconsistency.
However, given the trends of the past 24 hours, have boosted PoPs
into the Likely category for much of the forecast area on Sunday,
and added some light snow accumulation across the north. If the
models lock into a more southern solution, one that takes the
clipper just south of the forecast area like the current GFS,
temperatures will need to be lowered, PoPs raised, and snow amounts
boosted. For now, will be conservative with the changes until the
ultimate outcome is a little more clear.
For the remainder of the period, mostly quiet weather is expected. A
weak wave is most likely to impact the area Monday and again by
Thursday. However, these disturbances appear too weak to carry
mentionable precipitation at this time. Temperatures through the end
of the next work week should be at or above normal. The coolest
readings are likely Monday/Tuesday behind the main clipper, and
again Friday behind Thursday`s disturbance.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1123 AM CST FRI JAN 23 2015
Main concern in the short term will be with the timing of the
lifting of MVFR ceilings today. Clearing trend is making painfully
slow progress eastward. Have adjusted the timing of the clouds
scattering out based on the RAP model humidity level around 2000
feet, which would bring it to KPIA/KSPI around 23Z and to KCMI
around 01Z or so. This is a faster than a straight timing of the
cloud deck`s movement, as there are some thinning spots starting
to show up west of KPIA hinting at some potential afternoon
erosion, as suggested by the HRRR model. Any clearing will not
last terribly long, as mid and high clouds are already approaching
ahead of a frontal boundary that will be moving through the TAF
sites in the 10-14Z time frame on Saturday. While the front will
be dry, MVFR ceilings are likely to overspread central Illinois
Saturday morning following passage of the front.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Bak
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1202 PM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CIGS ARND 1500-1800FT AGL THRU 00Z...SLOWLY LIFTING TO ARND
2KFT AGL AFT 2Z.
* SOUTHWEST WINDS ARND 10-14KT WITH OCCASIONAL GUSTS TO 15-17KT
THRU 00Z.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS MORNING CONTINUED TO SHOW CONSIDERABLE CLOUD
COVER ACROSS THE REGION...WITH SOME CLEARING NOTED ACROSS EASTERN
IOWA. AS THE DAY HAS PROGRESSED SOME THINNING HAS BEGUN TO TAKE
PLACE ACROSS FAR NORTH/NORTHEAST ILLINOIS...AND MAY EVENTUALLY
MAKE IT INTO THE TAF SITES. AT THIS TIME THOUGH HAVE HELD ONTO THE
LOW CLOUDS THRU 00Z...WITH A SLOW IMPROVEMENT TOWARDS 2000-2500FT
AGL AFT 02Z. WINDS WILL CONTINUE TO BE SOUTHWESTERLY WITH SPEEDS
GENERALLY FROM 10-13KT. THRU THE AFTN ON OCCASION GUSTS MAY
OCCUR...AND NOT EXPECTED TO BE VERY FREQUENT WITH SPEEDS UP TO
17KT.
WITH A FRONTAL BOUNDARY SLIDING SOUTHEAST THIS EVENING...THERE IS
THE POTENTIAL FOR A FEW FLURRIES ACROSS ORD/MDW/DPA. ELSEWHERE
SHOULD BE TOO FAR REMOVED FROM THE BETTER MOISTURE TO SEE ANY
FLURRIES. THOUGH HAVE HELD ONTO A DRY FORECAST AS THIS TOO IS A
LOW CONFIDENCE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS REMAINING OVC THRU 23Z...MEDIUM
CONFIDENCE IN TIMING OF CIGS LIFTING HIGHER THAN 1600FT AGL.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1124 AM CST Fri Jan 23 2015
.UPDATE...
ISSUED AT 959 AM CST FRI JAN 23 2015
Have updated the forecast to slow the clearing trends and lower
the highs as a result. Clearing line is now just crossing the
Illinois/Iowa border. The latest RAP 925 mb humidity, which
appears to match the clouds fairly well, holds off on any
significant clearing in the northwest CWA until around mid
afternoon and not in the eastern CWA until after sunset. Have gone
with highs in the upper 30s over nearly all the forecast area,
except around 40 in west central Illinois where there is likely to
be some sunshine by mid to late afternoon.
&&
.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015
08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb. With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon. HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon. Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day. High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015
Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight. Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.
Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system. Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening. With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature. Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday. Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday. May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.
After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south. Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday. The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1123 AM CST FRI JAN 23 2015
Main concern in the short term will be with the timing of the
lifting of MVFR ceilings today. Clearing trend is making painfully
slow progress eastward. Have adjusted the timing of the clouds
scattering out based on the RAP model humidity level around 2000
feet, which would bring it to KPIA/KSPI around 23Z and to KCMI
around 01Z or so. This is a faster than a straight timing of the
cloud deck`s movement, as there are some thinning spots starting
to show up west of KPIA hinting at some potential afternoon
erosion, as suggested by the HRRR model. Any clearing will not
last terribly long, as mid and high clouds are already approaching
ahead of a frontal boundary that will be moving through the TAF
sites in the 10-14Z time frame on Saturday. While the front will
be dry, MVFR ceilings are likely to overspread central Illinois
Saturday morning following passage of the front.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1007 AM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR CEILINGS AROUND 1500 FT THROUGH THE AFTERNOON.
* WEST-SOUTHWEST WINDS 220-250 DEG 12-15 KT WITH A FEW HIGHER
GUSTS.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
AREA OF MVFR CEILINGS AROUND 1500 FT EXTENDS WEST ACROSS THE
MISSISSIPPI INTO EASTERN IOWA. BACK EDGE MAKING SLOW PROGRESS TO
THE EAST...THOUGH EXPECT SOME EROSION AND ACCELERATION OF THIS
DURING THE DAY WITH MVFR CEILINGS DISSIPATING OR MOVING EAST OF
THE TERMINALS BY EARLY THIS AFTERNOON. VFR CONDITIONS EXPECTED
LATER AFTERNOON THROUGH MOST OF TONIGHT...BEFORE SURFACE TROUGH
MOVES THROUGH DURING PRE-DAWN HOURS AND MVFR CIGS RETURN.
WINDS EXPECTED TO REMAIN WEST-SOUTHWEST 220-250 DEGREES THROUGH
THIS EVENING. SUSTAINED SPEEDS EXPECTED GENERALLY 10-15 KT WITH A
FEW HIGHER GUSTS UNDER 20 KTS. WINDS SHIFT WEST-NORTHWEST 290-310
DEG AFTER TROUGH PASSAGE EARLY SATURDAY MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH IN WIND DIRECTION...LOW IN GUST FREQUENCY.
* LOW IN MVFR CEILING DISSIPATION TIME.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1000 AM CST Fri Jan 23 2015
.UPDATE...
ISSUED AT 959 AM CST FRI JAN 23 2015
Have updated the forecast to slow the clearing trends and lower
the highs as a result. Clearing line is now just crossing the
Illinois/Iowa border. The latest RAP 925 mb humidity, which
appears to match the clouds fairly well, holds off on any
significant clearing in the northwest CWA until around mid
afternoon and not in the eastern CWA until after sunset. Have gone
with highs in the upper 30s over nearly all the forecast area,
except around 40 in west central Illinois where there is likely to
be some sunshine by mid to late afternoon.
&&
.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015
08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb. With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon. HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon. Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day. High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015
Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight. Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.
Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system. Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening. With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature. Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday. Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday. May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.
After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south. Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday. The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 500 AM CST FRI JAN 23 2015
Back edge of MVFR cigs making slow progress into extreme eastern
Iowa this morning and should push into our western TAF areas
between 16 and 18z. Based on the latest movement, it appears
the clouds won`t push east of CMI until after 22z. Forecast
soundings suggest that once the skies clear, we can expect VFR
conditions thru at least the first half of tonight before a
weak frontal boundary tracks thru the region switching our
flow from southwest to northwest and ushering in another batch
of MVFR cigs for Saturday. Surface flow today will increase out
of the southwest at 10 to 15 kts and then diminish some from the
southwest early this evening before switching into the west and
northwest later tonight with speeds of 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
531 AM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CEILINGS AROUND 1500 FT INTO EARLY AFTERNOON.
* WEST-SOUTHWEST WINDS 220-250 DEG 12-15 KT WITH A FEW HIGHER
GUSTS.
RATZER
//DISCUSSION...UPDATED 12Z...
AREA OF MVFR CEILINGS AROUND 1500 FT EXTENDS WEST ACROSS THE
MISSISSIPPI INTO EASTERN IOWA. BACK EDGE MAKING SLOW PROGRESS TO
THE EAST...THOUGH EXPECT SOME EROSION AND ACCELERATION OF THIS
DURING THE DAY WITH MVFR CEILINGS DISSIPATING OR MOVING EAST OF
THE TERMINALS BY EARLY THIS AFTERNOON. VFR CONDITIONS EXPECTED
LATER AFTERNOON THROUGH MOST OF TONIGHT...BEFORE SURFACE TROUGH
MOVES THROUGH DURING PRE-DAWN HOURS AND MVFR CIGS RETURN.
WINDS EXPECTED TO REMAIN WEST-SOUTHWEST 220-250 DEGREES THROUGH
THIS EVENING. SUSTAINED SPEEDS EXPECTED GENERALLY 10-15 KT WITH A
FEW HIGHER GUSTS UNDER 20 KTS. WINDS SHIFT WEST-NORTHWEST 290-310
DEG AFTER TROUGH PASSAGE EARLY SATURDAY MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH IN WIND DIRECTION...LOW IN GUST FREQUENCY.
* MEDIUM IN MVFR CEILING DISSIPATION TIME.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
503 AM CST Fri Jan 23 2015
.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015
08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb. With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon. HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon. Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day. High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015
Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight. Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.
Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system. Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening. With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature. Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday. Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday. May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.
After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south. Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday. The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 500 AM CST FRI JAN 23 2015
Backedge of MVFR cigs making slow progress into extreme eastern
Iowa this morning and should push into our western TAF areas
between 16 and 18z. Based on the latest movement, it appears
the clouds won`t push east of CMI until after 22z. Forecast
soundings suggest that once the skies clear, we can expect VFR
conditions thru at least the first half of tonight before a
weak frontal boundary tracks thru the region switching our
flow from southwest to northwest and ushering in another batch
of MVFR cigs for Saturday. Surface flow today will increase out
of the southwest at 10 to 15 kts and then diminish some from the
southwest early this evening before switching into the west and
northwest later tonight with speeds of 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
306 AM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CEILINGS AROUND 1500 FT LINGERING FRIDAY MORNING...
POSSIBLY LONGER.
* SOUTHWEST WINDS 10-15 KT...WITH A FEW HIGHER GUSTS POSSIBLE
FRIDAY AFTERNOON/EARLY EVENING.
RATZER
//DISCUSSION...UPDATED 06Z...
SURFACE HIGH PRESSURE EXTENDS FROM NORTHERN MISSOURI EAST ACROSS
INDIANA AND OHIO LATE THIS EVENING. WELL TO THE NORTH...AN AREA OF
LOW PRESSURE WAS MOVING SLOWLY EAST INTO ONTARIO. IN BETWEEN...
WEST-SOUTHWESTERLY SURFACE WINDS WILL BE THE RULE ACROSS THE UPPER
MIDWEST AND THE LOCAL TERMINALS THROUGH FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN A BIT DURING THE DAY FRIDAY...PRODUCING SUSTAINED
WINDS IN THE 12-15 KT RANGE WITH A FEW GUSTS IN THE 15-20 KT RANGE
POSSIBLE ESPECIALLY DURING THE LATER AFTERNOON AND EARLY EVENING
HOURS. AN APPROACHING SURFACE TROUGH WILL SHIFT WINDS TO THE WEST-
NORTHWEST BY EARLY SATURDAY MORNING.
SURFACE OBS AND SATELLITE IMAGERY INDICATES AN EXTENSIVE AREA OF
MVFR STRATUS ACROSS THE REGION...WHICH EXTENDS TO THE WEST ACROSS
MUCH OF EASTERN IOWA AND NORTHEAST MISSOURI. CURRENT EXTRAPOLATION
OF THE SLOW EASTWARD MOVEMENT OF THE WESTERN EDGE OF THIS CLOUD
DECK SUGGESTS MVFR CIGS COULD LINGER WELL INTO THE DAY FRIDAY
BEFORE SCATTERING...THOUGH EVENING RAOBS DEPICT THIS CLOUD LAYER
AS BEING FAIRLY SHALLOW AND PERHAPS 1000-2000 FT THICK. THIS
SUGGESTS THAT A FEW HOLES COULD DEVELOP IN THE OVERCAST EARLY THIS
MORNING WITH LARGE SCALE SINKING MOTION ALOFT...AND SOME MODEL
FORECAST SOUNDINGS SUPPORT THIS THOUGH PERHAPS COOL NEAR SFC LAYER
TOO MUCH. RECENT RAP RUNS MAINTAIN WARMER TEMPS BELOW THE STRATUS
AND DO NOT ERODE MOIST LAYER FROM ABOVE. THUS THERE IS SOMEWHAT
LOW CONFIDENCE IN CIG TRENDS THROUGH THIS MORNING. UNTIL THERE ARE
SOME SOLID SATELLITE TRENDS INDICATING EROSION OF THE MVFR DECK...
THINKING IS IT WILL LINGER UNTIL AT LEAST MID-MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH IN WIND TRENDS.
* MEDIUM-LOW IN TIMING EROSION/DEPARTURE OF MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR/WX NIL THROUGH EVENING. CHANCE SNOW LATE NIGHT.
MVFR CIGS/VIS POSSIBLE.
SUNDAY...RAIN/SNOW MIX...CHANGING TO RAIN DURG THE AFTERNOON.
LINGERING LIGHT SNOW POSSIBLE OVERNIGHT. PERIOD OF IFR CIGS/VIS
LIKELY.
MONDAY...SLIGHT CHANCE SNOW SHOWERS EARLY. MVFR CIGS/VIS POSSIBLE.
VFR/WX NIL OVERNIGHT.
TUESDAY...VFR/WX NIL.
WEDNESDAY...VFR/WX NIL.
KREIN
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
217 AM CST FRI JAN 23 2015
.SHORT TERM...
239 PM CST
TONIGHT...MAIN FOCUS FOR TONIGHT WILL BE ON CLOUD COVER. THIS WILL
ULTIMATELY DRIVE HOW COOL SFC TEMPS CAN BECOME AS WELL.
THIS AFTERNOON VISIBLE IMAGERY SHOWS SOME STEADY THINNING IN THE
CLOUD LAYER ACROSS MUCH OF CENTRAL/NORTHERN WISC...BUT THE CLOUDS
HOLDING TOUGH ACROSS NORTHERN IL/NORTHWEST IN AND POINTS SOUTH.
TEMPS HAVE REMAINED RATHER UNIFORM IN THE LOW 30S WITH A LIGHT
WEST/NORTHWEST WIND. THE SFC RIDGE REMAINS POSITIONED OVER THE
MID-MISSOURI VALLEY...BUT DRIFTING NORTHEAST. CURRENTLY EXPECT TEMPS
TO RADIATE INTO THE LOW/MID 20S BUT LIKELY WITH THE LINGERING CLOUDS
TEMPS MAY END UP REMAINING SEVERAL DEGREES WARMER.
FRIDAY THROUGH SATURDAY...
SFC RIDGE SHUD PROVIDE A P-CLOUDY START TO FRI...HOWEVER AN
APPROACHING BOUNDARY FROM THE NORTHWEST WILL QUICKLY BRING AN
INCREASING PLUME OF MOISTURE/CLOUDS. THE SFC LOW ASSOCIATED WITH THE
BOUNDARY WILL SKIRT THE NORTHERN GREAT LAKES...BUT COULD BRING SOME
FLURRIES TO FAR NORTH/NORTHEAST IL FRI AFTN. HOWEVER MOISTURE ALONG
THE SOUTHERN FLANK APPEARS TO BE MINIMAL...SO EXPECT MAINLY JUST
CLOUDS. THE DEPARTING SFC RIDGE SHUD PROVIDE ENOUGH DRY AIR THRU FRI
EVE TO KEEP PRECIP JUST NORTH OF THE FORECAST AREA.
500MB TROUGH AXIS WILL RESIDE OVER THE GREAT LAKES REGION...ALLOWING
A SERIES OF WEAK LOBES OF VORTICITY TO QUICKLY DIVE SOUTHEAST ACROSS
THE UPPER MIDWEST INTO THE GREAT LAKES REGION. FLOW SAT TURNS
NORTH/NORTHWEST...WHICH APPEARS TO SETUP SOME LAKE EFFECT FOR AREAS
DOWNSTREAM OF LAKE MICHIGAN. FOCUS SAT NGT TURNS TOWARDS A STRONGER
SHORTWAVE POISED TO DROP SOUTH FROM CENTRAL CANADA.
TEMPS FRI/SAT WILL GENERALLY BE IN THE MID 30S...BUT WITH A WEAK
NUDGE OF WARMER AIR SAT TEMPS COULD APPROACH THE UPR 30S...TO
POSSIBLY 40 ALONG THE SOUTHERN CWFA.
BEACHLER
&&
.LONG TERM...
239 PM CST
SUNDAY THROUGH MONDAY...
GUIDANCE CONTINUES TO DEMONSTRATE SPREAD ON THE TRACK OF THE SUN
SHORTWAVE ACROSS THE GREAT LAKES REGION...WITH SOLUTIONS BRINGING
THE LOW OVER EITHER LOWER MICHIGAN TO NORTHERN IL. WEAK NOSE OF
WARM AIR IS POISED TO ADVECT NORTH PRIOR TO SFC LOW
ARRIVAL...WHICH COULD BOOST SFC TEMPS TO ARND 40. THIS WILL LIKELY
MAKE P-TYPE A CHALLENGE. AT THIS TIME GIVEN THE SPREAD AMONGST
SOLUTIONS...HAVE OPTED TO ONLY MAKE MINOR ADJUSTMENTS. WILL
FEATURE RAIN/SNOW SUN...HOWEVER IF THE LOW TRACKS FURTHER SOUTH
THIS COULD SUPPRESS THE WARMER TEMPS AND KEEP PRECIP AS ALL SNOW.
AT THIS TIME THOUGH THIS SOLUTION IS A LOW CONFIDENCE.
ONCE THE LOW SLIDES SOUTH OF THE REGION SUN NGT...FLOW QUICKLY TURNS
NORTHEAST AND FETCH COULD BE LONG ENOUGH TO BRING A PERIOD OF LAKE
EFFECT SNOW TO NORTHEAST IL. DEEP MOISTURE THEN PEELS EAST WITH FLOW
SLOWLY TURNING NORTH/NORTHWESTERLY INTO MON EVE. ROBUST THERMAL
TROUGH TRAILS THE SHORTWAVE MON...WHICH WILL HELP TO KEEP TEMPS IN
THE UPR 20S FOR HIGHS MON.
TUESDAY THROUGH THURSDAY...
WITH THE 500MB FLOW REMAINING GENERALLY FROM THE NORTHWEST
TUE/WED...ANOTHER WEAK SHORTWAVE WILL TRAVERSE THE GREAT LAKES AND
POSSIBLY BRING SOME LIGHT SNOW TUE. THEN SFC RIDGING DEVELOPS
WED/THUR AND SHOULD PROVIDE A PERIOD OF DRY WEATHER FOR THE MIDDLE
OF NEXT WEEK. GUIDANCE SUGGESTS TEMPS SHUD RETURN TO SEASONAL CONDS
TOWARDS THE MIDDLE OF NEXT WEEK.
ENSEMBLES TRANSITION TOWARDS A HIGH AMPLITUDE RIDGE LIFTING INTO
WESTERN CANADA TOWARDS THE END OF NEXT WEEK...SETTING THE STAGE FOR
MUCH COLDER AIR TO SLOWLY SLIDE SOUTHEAST ACROSS THE GREAT LAKES
TOWARDS THE SECOND HALF OF NEXT WEEK.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CEILINGS AROUND 1500 FT LINGERING FRIDAY MORNING...
POSSIBLY LONGER.
* SOUTHWEST WINDS 10-15 KT...WITH A FEW HIGHER GUSTS POSSIBLE
FRIDAY AFTERNOON/EARLY EVENING.
RATZER
//DISCUSSION...UPDATED 06Z...
SURFACE HIGH PRESSURE EXTENDS FROM NORTHERN MISSOURI EAST ACROSS
INDIANA AND OHIO LATE THIS EVENING. WELL TO THE NORTH...AN AREA OF
LOW PRESSURE WAS MOVING SLOWLY EAST INTO ONTARIO. IN BETWEEN...
WEST-SOUTHWESTERLY SURFACE WINDS WILL BE THE RULE ACROSS THE UPPER
MIDWEST AND THE LOCAL TERMINALS THROUGH FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN A BIT DURING THE DAY FRIDAY...PRODUCING SUSTAINED
WINDS IN THE 12-15 KT RANGE WITH A FEW GUSTS IN THE 15-20 KT RANGE
POSSIBLE ESPECIALLY DURING THE LATER AFTERNOON AND EARLY EVENING
HOURS. AN APPROACHING SURFACE TROUGH WILL SHIFT WINDS TO THE WEST-
NORTHWEST BY EARLY SATURDAY MORNING.
SURFACE OBS AND SATELLITE IMAGERY INDICATES AN EXTENSIVE AREA OF
MVFR STRATUS ACROSS THE REGION...WHICH EXTENDS TO THE WEST ACROSS
MUCH OF EASTERN IOWA AND NORTHEAST MISSOURI. CURRENT EXTRAPOLATION
OF THE SLOW EASTWARD MOVEMENT OF THE WESTERN EDGE OF THIS CLOUD
DECK SUGGESTS MVFR CIGS COULD LINGER WELL INTO THE DAY FRIDAY
BEFORE SCATTERING...THOUGH EVENING RAOBS DEPICT THIS CLOUD LAYER
AS BEING FAIRLY SHALLOW AND PERHAPS 1000-2000 FT THICK. THIS
SUGGESTS THAT A FEW HOLES COULD DEVELOP IN THE OVERCAST EARLY THIS
MORNING WITH LARGE SCALE SINKING MOTION ALOFT...AND SOME MODEL
FORECAST SOUNDINGS SUPPORT THIS THOUGH PERHAPS COOL NEAR SFC LAYER
TOO MUCH. RECENT RAP RUNS MAINTAIN WARMER TEMPS BELOW THE STRATUS
AND DO NOT ERODE MOIST LAYER FROM ABOVE. THUS THERE IS SOMEWHAT
LOW CONFIDENCE IN CIG TRENDS THROUGH THIS MORNING. UNTIL THERE ARE
SOME SOLID SATELLITE TRENDS INDICATING EROSION OF THE MVFR DECK...
THINKING IS IT WILL LINGER UNTIL AT LEAST MID-MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN WIND TRENDS.
* MEDIUM-LOW IN TIMING EROSION/DEPARTURE OF MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR/WX NIL THROUGH EVENING. CHANCE SNOW LATE NIGHT.
MVFR CIGS/VIS POSSIBLE.
SUNDAY...RAIN/SNOW MIX...CHANGING TO RAIN DURG THE AFTERNOON.
LINGERING LIGHT SNOW POSSIBLE OVERNIGHT. PERIOD OF IFR CIGS/VIS
LIKELY.
MONDAY...SLIGHT CHANCE SNOW SHOWERS EARLY. MVFR CIGS/VIS POSSIBLE.
VFR/WX NIL OVERNIGHT.
TUESDAY...VFR/WX NIL.
WEDNESDAY...VFR/WX NIL.
KREIN
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1158 PM CST THU JAN 22 2015
.SHORT TERM...
239 PM CST
TONIGHT...MAIN FOCUS FOR TONIGHT WILL BE ON CLOUD COVER. THIS WILL
ULTIMATELY DRIVE HOW COOL SFC TEMPS CAN BECOME AS WELL.
THIS AFTERNOON VISIBLE IMAGERY SHOWS SOME STEADY THINNING IN THE
CLOUD LAYER ACROSS MUCH OF CENTRAL/NORTHERN WISC...BUT THE CLOUDS
HOLDING TOUGH ACROSS NORTHERN IL/NORTHWEST IN AND POINTS SOUTH.
TEMPS HAVE REMAINED RATHER UNIFORM IN THE LOW 30S WITH A LIGHT
WEST/NORTHWEST WIND. THE SFC RIDGE REMAINS POSITIONED OVER THE
MID-MISSOURI VALLEY...BUT DRIFTING NORTHEAST. CURRENTLY EXPECT TEMPS
TO RADIATE INTO THE LOW/MID 20S BUT LIKELY WITH THE LINGERING CLOUDS
TEMPS MAY END UP REMAINING SEVERAL DEGREES WARMER.
FRIDAY THROUGH SATURDAY...
SFC RIDGE SHUD PROVIDE A P-CLOUDY START TO FRI...HOWEVER AN
APPROACHING BOUNDARY FROM THE NORTHWEST WILL QUICKLY BRING AN
INCREASING PLUME OF MOISTURE/CLOUDS. THE SFC LOW ASSOCIATED WITH THE
BOUNDARY WILL SKIRT THE NORTHERN GREAT LAKES...BUT COULD BRING SOME
FLURRIES TO FAR NORTH/NORTHEAST IL FRI AFTN. HOWEVER MOISTURE ALONG
THE SOUTHERN FLANK APPEARS TO BE MINIMAL...SO EXPECT MAINLY JUST
CLOUDS. THE DEPARTING SFC RIDGE SHUD PROVIDE ENOUGH DRY AIR THRU FRI
EVE TO KEEP PRECIP JUST NORTH OF THE FORECAST AREA.
500MB TROUGH AXIS WILL RESIDE OVER THE GREAT LAKES REGION...ALLOWING
A SERIES OF WEAK LOBES OF VORTICITY TO QUICKLY DIVE SOUTHEAST ACROSS
THE UPPER MIDWEST INTO THE GREAT LAKES REGION. FLOW SAT TURNS
NORTH/NORTHWEST...WHICH APPEARS TO SETUP SOME LAKE EFFECT FOR AREAS
DOWNSTREAM OF LAKE MICHIGAN. FOCUS SAT NGT TURNS TOWARDS A STRONGER
SHORTWAVE POISED TO DROP SOUTH FROM CENTRAL CANADA.
TEMPS FRI/SAT WILL GENERALLY BE IN THE MID 30S...BUT WITH A WEAK
NUDGE OF WARMER AIR SAT TEMPS COULD APPROACH THE UPR 30S...TO
POSSIBLY 40 ALONG THE SOUTHERN CWFA.
BEACHLER
&&
.LONG TERM...
239 PM CST
SUNDAY THROUGH MONDAY...
GUIDANCE CONTINUES TO DEMONSTRATE SPREAD ON THE TRACK OF THE SUN
SHORTWAVE ACROSS THE GREAT LAKES REGION...WITH SOLUTIONS BRINGING
THE LOW OVER EITHER LOWER MICHIGAN TO NORTHERN IL. WEAK NOSE OF
WARM AIR IS POISED TO ADVECT NORTH PRIOR TO SFC LOW
ARRIVAL...WHICH COULD BOOST SFC TEMPS TO ARND 40. THIS WILL LIKELY
MAKE P-TYPE A CHALLENGE. AT THIS TIME GIVEN THE SPREAD AMONGST
SOLUTIONS...HAVE OPTED TO ONLY MAKE MINOR ADJUSTMENTS. WILL
FEATURE RAIN/SNOW SUN...HOWEVER IF THE LOW TRACKS FURTHER SOUTH
THIS COULD SUPPRESS THE WARMER TEMPS AND KEEP PRECIP AS ALL SNOW.
AT THIS TIME THOUGH THIS SOLUTION IS A LOW CONFIDENCE.
ONCE THE LOW SLIDES SOUTH OF THE REGION SUN NGT...FLOW QUICKLY TURNS
NORTHEAST AND FETCH COULD BE LONG ENOUGH TO BRING A PERIOD OF LAKE
EFFECT SNOW TO NORTHEAST IL. DEEP MOISTURE THEN PEELS EAST WITH FLOW
SLOWLY TURNING NORTH/NORTHWESTERLY INTO MON EVE. ROBUST THERMAL
TROUGH TRAILS THE SHORTWAVE MON...WHICH WILL HELP TO KEEP TEMPS IN
THE UPR 20S FOR HIGHS MON.
TUESDAY THROUGH THURSDAY...
WITH THE 500MB FLOW REMAINING GENERALLY FROM THE NORTHWEST
TUE/WED...ANOTHER WEAK SHORTWAVE WILL TRAVERSE THE GREAT LAKES AND
POSSIBLY BRING SOME LIGHT SNOW TUE. THEN SFC RIDGING DEVELOPS
WED/THUR AND SHOULD PROVIDE A PERIOD OF DRY WEATHER FOR THE MIDDLE
OF NEXT WEEK. GUIDANCE SUGGESTS TEMPS SHUD RETURN TO SEASONAL CONDS
TOWARDS THE MIDDLE OF NEXT WEEK.
ENSEMBLES TRANSITION TOWARDS A HIGH AMPLITUDE RIDGE LIFTING INTO
WESTERN CANADA TOWARDS THE END OF NEXT WEEK...SETTING THE STAGE FOR
MUCH COLDER AIR TO SLOWLY SLIDE SOUTHEAST ACROSS THE GREAT LAKES
TOWARDS THE SECOND HALF OF NEXT WEEK.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CEILINGS AROUND 1500 FT LINGERING FRIDAY MORNING...
POSSIBLY LONGER.
* SOUTHWEST WINDS 10-15 KT...WITH A FEW HIGHER GUSTS POSSIBLE
FRIDAY AFTERNOON/EARLY EVENING.
RATZER
//DISCUSSION...UPDATED 06Z...
SURFACE HIGH PRESSURE EXTENDS FROM NORTHERN MISSOURI EAST ACROSS
INDIANA AND OHIO LATE THIS EVENING. WELL TO THE NORTH...AN AREA OF
LOW PRESSURE WAS MOVING SLOWLY EAST INTO ONTARIO. IN BETWEEN...
WEST-SOUTHWESTERLY SURFACE WINDS WILL BE THE RULE ACROSS THE UPPER
MIDWEST AND THE LOCAL TERMINALS THROUGH FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN A BIT DURING THE DAY FRIDAY...PRODUCING SUSTAINED
WINDS IN THE 12-15 KT RANGE WITH A FEW GUSTS IN THE 15-20 KT RANGE
POSSIBLE ESPECIALLY DURING THE LATER AFTERNOON AND EARLY EVENING
HOURS. AN APPROACHING SURFACE TROUGH WILL SHIFT WINDS TO THE WEST-
NORTHWEST BY EARLY SATURDAY MORNING.
SURFACE OBS AND SATELLITE IMAGERY INDICATES AN EXTENSIVE AREA OF
MVFR STRATUS ACROSS THE REGION...WHICH EXTENDS TO THE WEST ACROSS
MUCH OF EASTERN IOWA AND NORTHEAST MISSOURI. CURRENT EXTRAPOLATION
OF THE SLOW EASTWARD MOVEMENT OF THE WESTERN EDGE OF THIS CLOUD
DECK SUGGESTS MVFR CIGS COULD LINGER WELL INTO THE DAY FRIDAY
BEFORE SCATTERING...THOUGH EVENING RAOBS DEPICT THIS CLOUD LAYER
AS BEING FAIRLY SHALLOW AND PERHAPS 1000-2000 FT THICK. THIS
SUGGESTS THAT A FEW HOLES COULD DEVELOP IN THE OVERCAST EARLY THIS
MORNING WITH LARGE SCALE SINKING MOTION ALOFT...AND SOME MODEL
FORECAST SOUNDINGS SUPPORT THIS THOUGH PERHAPS COOL NEAR SFC LAYER
TOO MUCH. RECENT RAP RUNS MAINTAIN WARMER TEMPS BELOW THE STRATUS
AND DO NOT ERODE MOIST LAYER FROM ABOVE. THUS THERE IS SOMEWHAT
LOW CONFIDENCE IN CIG TRENDS THROUGH THIS MORNING. UNTIL THERE ARE
SOME SOLID SATELLITE TRENDS INDICATING EROSION OF THE MVFR DECK...
THINKING IS IT WILL LINGER UNTIL AT LEAST MID-MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN WIND TRENDS.
* MEDIUM-LOW IN TIMING EROSION/DEPARTURE OF MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR/WX NIL THROUGH EVENING. CHANCE SNOW LATE NIGHT.
MVFR CIGS/VIS POSSIBLE.
SUNDAY...RAIN/SNOW MIX...CHANGING TO RAIN DURG THE AFTERNOON.
LINGERING LIGHT SNOW POSSIBLE OVERNIGHT. PERIOD OF IFR CIGS/VIS
LIKELY.
MONDAY...SLIGHT CHANCE SNOW SHOWERS EARLY. MVFR CIGS/VIS POSSIBLE.
VFR/WX NIL OVERNIGHT.
TUESDAY...VFR/WX NIL.
WEDNESDAY...VFR/WX NIL.
KREIN
&&
.MARINE...
150 PM CST
WINDS WILL BEGIN TO INCREASE OVER THE OPEN WATERS OUT OF THE
WEST-SOUTHWEST THIS EVENING AS AN AREA OF LOW PRESSURE SHIFTS
SOUTHEASTWARD FROM NORTHERN MANITOBA INTO NORTHWESTERN ONTARIO. THIS
SYSTEM WILL SET UP A STOUT PRESSURE GRADIENT OVER THE LAKE AS HIGH
PRESSURE SETS UP FROM THE PLAINS TO THE OHIO VALLEY. THIS SHOULD
SUPPORT A PERIOD OF GALE FORCE WINDS OVER THE NORTHERN 1/3RD OR SO
OF LAKE MICHIGAN INTO FRIDAY. WIND SPEEDS ACROSS FAR SOUTHERN LAKE
MICHIGAN WILL LIKELY REMAIN LIGHTER DUE TO THE CLOSER PROXIMATE TO
THE SURFACE HIGH. THEREFORE...SMALL CRAFT ADVISORY CONDITIONS ARE NOT
ANTICIPATED FOR THE ILLINOIS AND INDIANA NEAR SHORES. NO CHANGES
HAVE BEEN MADE TO THE TIMING OF THE CURRENT GALE WARNING.
A COLD FRONT...ASSOCIATED WITH THE AFOREMENTIONED SURFACE LOW...WILL
SHIFT ACROSS THE LAKE INTO SATURDAY. THIS WILL SET UP A PERIOD OF
LIGHTER NORTHWESTERLY WINDS. ANOTHER CLIPPER SYSTEM IS EXPECTED TO
APPROACH THE LAKE BY SUNDAY. HOWEVER...THERE CONTINUES TO BE
UNCERTAINTY ON WHERE THIS SYSTEM WILL TRACK. THIS WILL HAVE LARGE
CONSEQUENCES ON THE WIND FORECAST FOR SUNDAY. IF THE SYSTEM TRACKS
TO THE SOUTH OF THE LAKE...THIS COULD LEAD TO A PERIOD OF STOUT EAST
NORTHEASTERLY WINDS DOWN MUCH OF THE LAKE...WHICH COULD PRODUCE
HIGHER WAVES INTO THE ILLINOIS AND INDIANA NEAR SHORES. HOWEVER...A
FARTHER NORTH TRACK WOULD RESULT IN A SHORTER PERIOD OF NORTHERLY
WINDS ON SUNDAY...ESPECIALLY ACROSS THE SOUTHERN END OF LAKE
MICHIGAN. AT THIS TIME...GALE FORCE WINDS ARE NOT ANTICIPATED WITH
THIS SYSTEM. HOWEVER...25 TO 30 KT WINDS ARE POSSIBLE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
109 PM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 400 AM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
REMAIN CLOUDY THIS MORNING BUT A FEW BREAKS IN THE CLOUD COVER
MAY DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL
GENERALLY BE IN THE 30S AND LOWS TONIGHT WILL GENERALLY BE IN THE
20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 23 2015
A WEAK RIDGE OF HIGH PRESSURE WAS NORTH OF THE OHIO RIVER...LIKE
AN INACTIVE COL AREA BETWEEN THE DEVELOPING LOW TO THE SOUTH AND
THE APPROACHING SHORTWAVE TROF AND ASSOCIATED SURFACE TROF TO THE
WEST. AIRCRAFT OBSERVATIONS AND EARLY MORNING REGIONAL SOUNDINGS
SHOWED THE INVERSION DEEPENING FROM NORTHEAST TO SOUTHWEST. GIVEN
THIS INVERSION WITH THE COL AREA IN CLOSE PROXIMITY...THE MODELS
APPEAR TO BE CLEARING SKIES AND IMPROVING CONDITIONS TOO FAST...
ESPECIALLY THE GFS. HAVE GONE MORE PESSIMISTIC WITH IMPROVING
CONDITIONS GIVEN ALL OF THESE FACTORS AS BOTH SBN AND FWA OBS
STILL NEAR 015 OVC. THEREFORE... KEPT MVFR AT BOTH SITES FOR THE
ENTIRE TAF PERIOD AT 17Z. TAFS STILL MAY BE TOO OPTIMISTIC WITH
CEILING IMPROVEMENT TO 020...BUT STILL HOPEFUL OF THIS IMPROVEMENT
GIVEN THE 020 MINIMUM FOR FUEL ALTERNATE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...SKIPPER
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1250 PM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 1250 PM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
LIKELY REMAIN CLOUDY BUT A FEW BREAKS IN THE OVERCAST ARE POSSIBLE.
HIGH TEMPERATURES BE IN THE 30S AND LOWS TONIGHT WILL BE IN THE 20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 631 AM EST FRI JAN 23 2015
MVFR CIGS REMAIN THE ISSUE TODAY. SATELLITE SHOWS EXTENSIVE AND
SOLID CLOUD DECK EXTENDING WEST TO NEAR MS RIVER AT 11Z. SLOW
EROSION WAS NOTED WITH CLEARING WORKING SLOWLY EAST. SEVERAL HIRES
MODEL SOUNDINGS INDICATE INVERSION WILL PERSIST AND LOCK LOW LEVEL
MOISTURE IN THROUGH TONIGHT. OTHER GUIDANCE SUGGEST THIN LAYER OF
MOISTURE TO MIX TODAY WITH WEAK FLOW AND SUBSIDENCE. HAVE TRIED TO
BE A BIT OPTIMISTIC WITH CIGS GRADUALLY RISING AND BECOMING BKN
THIS AFTERNOON. BROUGHT FLIGHT CATEGORY UP TO VFR BY EARLY THIS
EVENING ASSUMING BREAKS DO DEVELOP.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MLR
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
637 AM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 400 AM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
REMAIN CLOUDY THIS MORNING BUT A FEW BREAKS IN THE CLOUD COVER
MAY DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL
GENERALLY BE IN THE 30S AND LOWS TONIGHT WILL GENERALLY BE IN THE
20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 631 AM EST FRI JAN 23 2015
MVFR CIGS REMAIN THE ISSUE TODAY. SATELLITE SHOWS EXTENSIVE AND
SOLID CLOUD DECK EXTENDING WEST TO NEAR MS RIVER AT 11Z. SLOW
EROSION WAS NOTED WITH CLEARING WORKING SLOWLY EAST. SEVERAL HIRES
MODEL SOUNDINGS INDICATE INVERSION WILL PERSIST AND LOCK LOW LEVEL
MOISTURE IN THROUGH TONIGHT. OTHER GUIDANCE SUGGEST THIN LAYER OF
MOISTURE TO MIX TODAY WITH WEAK FLOW AND SUBSIDENCE. HAVE TRIED TO
BE A BIT OPTIMISTIC WITH CIGS GRADUALLY RISING AND BECOMING BKN
THIS AFTERNOON. BROUGHT FLIGHT CATEGORY UP TO VFR BY EARLY THIS
EVENING ASSUMING BREAKS DO DEVELOP.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
406 AM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 400 AM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
REMAIN CLOUDY THIS MORNING BUT A FEW BREAKS IN THE CLOUD COVER
MAY DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL
GENERALLY BE IN THE 30S AND LOWS TONIGHT WILL GENERALLY BE IN THE
20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1232 AM EST FRI JAN 23 2015
LOW CLOUDS REMAIN LOCKED UNDER STRONG INVERSION WITH SURFACE HIGH
PRESSURE OVER THE REGION. DO NOT EXPECT THIS MVFR CLOUD DECK TO
DISSIPATE OVERNIGHT AS SOUTHWEST FLOW ALOFT IS LOCKING INVERSION
IN PLACE AND SATELLITE SHOWS CLOUD DECK EXPANDING. LATEST HIRES
GUIDANCE INDICATES INVERSION TO HOLD THROUGH FRIDAY WITH MOISTURE
TRAPPED OVER OUR AREA. SUBSIDENCE COULD WORK ON THE THIN LAYER
DURING THE DAY BUT WOULD ONLY EXPECT SOME BREAKS TO DEVELOP IN
AFTERNOON VERSUS FULL CLEARING. THUS HAVE KEPT TAFS IN THE MVFR
RANGE FOR THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1132 AM CST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 320 AM CST FRI JAN 23 2015
NORTHWEST FLOW WILL CONTINUE THROUGH THE NEXT ONE TO TWO WEEKS. A
SERIES OF WEATHER SYSTEMS WILL MOVE THROUGH THE AREA OVER THE NEXT
SEVERAL DAYS.
&&
.SHORT TERM /TODAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
A WEAK TROUGH LOOKS TO QUICKLY PUSH THROUGH THE STATE LATE
THIS MORNING AND INTO THE AFTERNOON. THERE IS SOME WEAK 700-500MB
THETA-E ADVECTION AND MID-LEVEL FORCING WITH THIS CLIPPER...BUT
TREMENDOUS AMOUNT OF DRY AIR BELOW 700MB TO THE SURFACE WILL MAKE
IT DIFFICULT FOR ANY PRECIP FALLING THROUGH THIS LAYER TO REACH
THE GROUND. LOWERED POPS AND HAVE ONLY SPRINKLES MENTIONED WITH
THE LOWER CONFIDENCE OF MEASURABLE PRECIP. THE 23.03Z HOPWRF AND
LATEST HRRR HAVE A GOOD HANDLE OF THE VERY LIGHT
PRECIP/REFLECTIVITY TRENDS LATE THIS MORNING INTO THE EARLY
AFTERNOON OVER NORTHERN IOWA.
DECENT WAA AHEAD OF THE WEAK TROUGH TODAY AND WENT WELL ABOVE
GUIDANCE OVER THE CENTRAL TO SOUTH. THE RUC13 HAS A VERY GOOD
HANDLE ON THE MAX TEMPS TREND TODAY AND LEANED TOWARDS THE
23.07Z RUN. THE CLOUD COVER MOVING IN WITH THE SHORTWAVE IS THE
CAVEAT...THE QUESTION REMAINS IF CLOUD DECK WILL MOVE IN QUICK
ENOUGH TO HOLD TEMPS DOWN. LEANED TOWARD THE WAA AND ENOUGH
SUNSHINE EARLY ON IN THE DAY TO PUT TEMPS WELL INTO THE 40S...AND
THUS TWEAKED UP MAX TEMPS OVER THE SOUTHERN HALF OF THE FORECAST.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
TROUGH OF LOW PRESSURE FROM NWRN MN INTO CO WILL MOVE THROUGH THE
AREAS TODAY. SWLY FLOW WILL BRING WARMER AIR TO THE STATE TODAY.
THE COOLING WILL BE SHORT LIVED AS THE NEXT WEATHER DISTURBANCE
WILL MOVE THROUGH SUNDAY INTO SUNDAY EVENING. SOME DISCREPANCY
WITH THE TRACK...HOW FAR SOUTHWEST...ON IT. THE ECMWF IS AMONG THE
FARTHEST WEST...BUT EVEN SO THE TRACK IS FAR ENOUGH TO THE
NORTHEAST THAT MUCH OF IA WILL BE IN THE RAIN AREA...OR REMAIN
DRY WITH ANY FROZEN PRECIP OVER THE FAR NORTHEAST.
A STRONGER SYSTEM WILL MOVE THROUGH MID WEEK. A STRONG PUSH OF
WARM AIR IS EXPECTED AHEAD OF THIS SYSTEM AND WENT WELL ABOVE MOS
FOR HIGHS ON WED. ONCE THE SYSTEM PASSES...A TRANSITION IN THE
PATTERN WILL BEGIN. THE STORM TRACK WILL SHIFT FARTHER TO THE WEST
AND ARCTIC AIR WILL BEGIN TO SPILL INTO THE CENTRAL U.S.
&&
.AVIATION...23/18Z
ISSUED AT 1132 AM CST FRI JAN 23 2015
OVERNIGHT A STRATUS DECK COULD DEVELOP AND MOVING INTO THE
AREA...BUT CONFIDENCE IS RELATIVELY LOW. SATELLITE IMAGERY DEPICTS
SUCH CLOUDS APPROACHING FROM NORTHERN MN BUT ON A TRAJECTORY TO
JUST CLIP NORTHEAST IA. ALL MODEL GUIDANCE INDICATES DEVELOPMENT
OF LOW CLOUDS OVER EASTERN SD AND WESTERN MN TODAY...APPARENTLY
THOSE THAT WOULD FOLLOW THE STEERING FLOW DOWN INTO CENTRAL IOWA
TONIGHT...BUT CURRENTLY SATELLITE AND OBSERVATIONS SHOW CLEAR
SKIES OVER THOSE AREAS. SUSPECT THAT THE MODELS POOR HANDLE ON
CURRENT SNOW COVER MAY BE LEADING TO OVERZEALOUS PREDICTIONS OF
NEAR SURFACE MOISTURE AND CLOUD DEVELOPMENT. HOWEVER...WITH MVFR
CIGS ALREADY IN THE TAFS HAVE MAINTAINED THEM AND WILL WATCH
OBSERVATIONAL TRENDS TO OUR NORTHWEST THIS AFTERNOON AND TONIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS JAN 15
SHORT TERM...PODRAZIK
LONG TERM...MS JAN 15
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
539 AM CST FRI JAN 23 2015
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 320 AM CST FRI JAN 23 2015
A NORTHWEST FLOW WILL CONTINUE THROUGH THE NEXT ONE TO TWO WEEKS.
A SERIES WEATHER SYSTEMS WILL MOVE THROUGH THE AREAS OVER THE NXT
SEVERAL DAYS.
&&
.SHORT TERM /TODAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
A WEAK TROUGH LOOKS TO QUICKLY PUSH THROUGH THE STATE LATE
THIS MORNING AND INTO THE AFTERNOON. THERE IS SOME WEAK 700-500MB
THETA-E ADVECTION AND MID-LEVEL FORCING WITH THIS CLIPPER...BUT
TREMENDOUS AMOUNT OF DRY AIR BELOW 700MB TO THE SURFACE WILL MAKE
IT DIFFICULT FOR ANY PRECIP FALLING THROUGH THIS LAYER TO REACH
THE GROUND. LOWERED POPS AND HAVE ONLY SPRINKLES MENTIONED WITH
THE LOWER CONFIDENCE OF MEASURABLE PRECIP. THE 23.03Z HOPWRF AND
LATEST HRRR HAVE A GOOD HANDLE OF THE VERY LIGHT
PRECIP/REFLECTIVITY TRENDS LATE THIS MORNING INTO THE EARLY
AFTERNOON OVER NORTHERN IOWA.
DECENT WAA AHEAD OF THE WEAK TROUGH TODAY AND WENT WELL ABOVE
GUIDANCE OVER THE CENTRAL TO SOUTH. THE RUC13 HAS A VERY GOOD
HANDLE ON THE MAX TEMPS TREND TODAY AND LEANED TOWARDS THE
23.07Z RUN. THE CLOUD COVER MOVING IN WITH THE SHORTWAVE IS THE
CAVEAT...THE QUESTION REMAINS IF CLOUD DECK WILL MOVE IN QUICK
ENOUGH TO HOLD TEMPS DOWN. LEANED TOWARD THE WAA AND ENOUGH
SUNSHINE EARLY ON IN THE DAY TO PUT TEMPS WELL INTO THE 40S...AND
THUS TWEAKED UP MAX TEMPS OVER THE SOUTHERN HALF OF THE FORECAST.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
TROUGH OF LOW PRESSURE FROM NWRN MN INTO CO WILL MOVE THROUGH THE
AREAS TODAY. SWLY FLOW WILL BRING WARMER AIR TO THE STATE TODAY.
THE COOLING WILL BE SHORT LIVED AS THE NEXT WEATHER DISTURBANCE
WILL MOVE THROUGH SUNDAY INTO SUNDAY EVENING. SOME DISCREPANCY
WITH THE TRACK...HOW FAR SOUTHWEST...ON IT. THE ECMWF IS AMONG THE
FARTHEST WEST...BUT EVEN SO THE TRACK IS FAR ENOUGH TO THE
NORTHEAST THAT MUCH OF IA WILL BE IN THE RAIN AREA...OR REMAIN
DRY WITH ANY FROZEN PRECIP OVER THE FAR NORTHEAST.
A STRONGER SYSTEM WILL MOVE THROUGH MID WEEK. A STRONG PUSH OF
WARM AIR IS EXPECTED AHEAD OF THIS SYSTEM AND WENT WELL ABOVE MOS
FOR HIGHS ON WED. ONCE THE SYSTEM PASSES...A TRANSITION IN THE
PATTERN WILL BEGIN. THE STORM TRACK WILL SHIFT FARTHER TO THE WEST
AND ARCTIC AIR WILL BEGIN TO SPILL INTO THE CENTRAL U.S.
&&
.AVIATION...23/12Z
ISSUED AT 536 AM CST FRI JAN 23 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE FIRST 6-12 HOURS OF THE
TAF PERIOD BEFORE LOW LEVEL MOISTURE ADVECTS BACK INTO THE STATE
LATE THIS EVENING INTO SATURDAY MORNING. SOUNDINGS SUGGESTS
POTENTIAL FOR IFR CIGS BUT KEPT LOWER END OF MVFR CIGS ATTM DUE TO
LOW CONFIDENCE MENTIONING IFR/LIFR CIGS SO LATE IN THE TAF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS JAN 15
SHORT TERM...PODRAZIK
LONG TERM...MS JAN 15
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
344 AM CST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 320 AM CST FRI JAN 23 2015
A NORTHWEST FLOW WILL CONTINUE THROUGH THE NEXT ONE TO TWO WEEKS.
A SERIES WEATHER SYSTEMS WILL MOVE THROUGH THE AREAS OVER THE NXT
SEVERAL DAYS.
&&
.SHORT TERM /TODAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
A WEAK TROUGH LOOKS TO QUICKLY PUSH THROUGH THE STATE LATE
THIS MORNING AND INTO THE AFTERNOON. THERE IS SOME WEAK 700-500MB
THETA-E ADVECTION AND MID-LEVEL FORCING WITH THIS CLIPPER...BUT
TREMENDOUS AMOUNT OF DRY AIR BELOW 700MB TO THE SURFACE WILL MAKE IT
DIFFICULT FOR ANY PRECIP FALLING THROUGH THIS LAYER TO REACH THE
GROUND. LOWERED POPS AND HAVE ONLY SPRINKLES MENTIONED WITH THE
LOWER CONFIDENCE OF MEASURABLE PRECIP. THE 23.03Z HOPWRF AND LATEST
HRRR HAVE A GOOD HANDLE OF THE VERY LIGHT PRECIP/REFLECTIVITY TRENDS
LATE THIS MORNING INTO THE EARLY AFTERNOON OVER NORTHERN IOWA.
DECENT WAA AHEAD OF THE WEAK TROUGH TODAY AND WENT WELL ABOVE
GUIDANCE OVER THE CENTRAL TO SOUTH. THE RUC13 HAS A VERY GOOD HANDLE
ON THE MAX TEMPS TREND TODAY AND LEANED TOWARDS THE 23.07Z RUN. THE
CLOUD COVER MOVING IN WITH THE SHORTWAVE IS THE CAVEAT...THE
QUESTION REMAINS IF CLOUD DECK WILL MOVE IN QUICK ENOUGH TO HOLD
TEMPS DOWN. LEANED TOWARD THE WAA AND ENOUGH SUNSHINE EARLY ON IN
THE DAY TO PUT TEMPS WELL INTO THE 40S...AND THUS TWEAKED UP MAX
TEMPS OVER THE SOUTHERN HALF OF THE FORECAST.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
TROUGH OF LOW PRESSURE FROM NWRN MN INTO CO WILL MOVE THROUGH THE
AREAS TODAY. SWLY FLOW WILL BRING WARMER AIR TO THE STATE TODAY.
THE COOLING WILL BE SHORT LIVED AS THE NEXT WEATHER DISTURBANCE
WILL MOVE THROUGH SUNDAY INTO SUNDAY EVENING. SOME DISCREPANCY
WITH THE TRACK...HOW FAR SOUTHWEST...ON IT. THE ECMWF IS AMONG THE
FARTHEST WEST...BUT EVEN SO THE TRACK IS FAR ENOUGH TO THE
NORTHEAST THAT MUCH OF IA WILL BE IN THE RAIN AREA...OR REMAIN
DRY WITH ANY FROZEN PRECIP OVER THE FAR NORTHEAST.
A STRONGER SYSTEM WILL MOVE THROUGH MID WEEK. A STRONG PUSH OF
WARM AIR IS EXPECTED AHEAD OF THIS SYSTEM AND WENT WELL ABOVE MOS
FOR HIGHS ON WED. ONCE THE SYSTEM PASSES...A TRANSITION IN THE
PATTERN WILL BEGIN. THE STORM TRACK WILL SHIFT FARTHER TO THE WEST
AND ARCTIC AIR WILL BEGIN TO SPILL INTO THE CENTRAL U.S.
&&
.AVIATION...23/00Z
ISSUED AT 551 PM CST THU JAN 22 2015
STRATUS DECK HAS PRETTY MUCH CLEARED OUT OF THE AREA...WITH MAINLY
VFR CONDITIONS EXPECTED INTO FRIDAY. SOUTHERLY WINDS TO PICK UP
FRIDAY...AND BECOME A LITTLE GUSTY. A COLD FRONT TO MOVE THROUGH
FRIDAY EVENING...WITH WINDS SHIFTING AROUND TO THE NORTHWEST AND A
LOW STRATUS DECK TO MOVE IN WITH AT LEAST MVFR CIGS EXPECTED.
POSSIBILITY OF IFR CIGS...BUT UNCERTAINTY STILL HIGH SO HAVE GONE
WITH A MENTION OF LOW MVFR.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MS JAN 15
SHORT TERM...PODRAZIK
LONG TERM...MS JAN 15
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1134 PM CST THU JAN 22 2015
.UPDATE...
ISSUED AT 524 PM CST THU JAN 22 2015
BASED ON THE CURRENT RATE OF THE EASTWARD PROGRESSION OF THE BACK
EDGE OF THE STRATUS IN WESTERN IA...AND TRENDS OF THE HRRR AND RAP
THAT HAD A DECENT HANDLE ON THESE FEATURES...CLEARING WILL LIKELY
TAKE LONGER THAN ORIGINALLY EXPECTED. HAVE UPDATED THE FORECAST
FOR THE CLEARING TO REACH OUR WESTERN FORECAST AREA BORDER AROUND
MIDNIGHT...THEN CROSS THE MS RIVER AROUND 5 AM. THIS WOULD LEAVE
OUR ILLINOIS ZONES UNDER CLOUD COVER THROUGH THE NIGHT. FOR
NOW...HAVE MADE ONLY MINOR TWEAKS TO HOURLY TEMPERATURES...BUT
WILL NEED TO REASSESS FOR POSSIBLE WARMER LOWS WITH THE MORE
PERSISTENT CLOUD COVER.
&&
.SYNOPSIS...
ISSUED AT 346 PM CST THU JAN 22 2015
UPPER LEVEL TROUGH ALONG WITH A STRENGTHENING INVERSION AT 900 MB
TRAPPING THE LOW LEVEL MOISTURE BELOW...DESPITE SURFACE HIGH
PRESSURE OVER THE CWA. THIS HAS RESULTED IN AN EXTENSIVE AREA OF
STRATUS TODAY ACROSS THE CWA. 3 PM TEMPERATURES RANGED FROM THE
UPPER 20S TO MID 30S.
ELSEWHERE...SUBSIDENCE BEHIND THE DEPARTING TROUGH WAS CLEARING
THE SKIES IN WISCONSIN AND ALSO WESTERN IA/WESTERN MN. HOWEVER...THE
CLEARING HAS COME TO A GRINDING HALT IN SOUTHERN WI BUT CONTINUES
TO MAKE SLOW BUT STEADY PROGRESS EASTWARD IN WESTERN IA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 346 PM CST THU JAN 22 2015
FORECAST FOCUS ON CLOUDS AND TEMPERATURES. WARMER ON FRIDAY.
TONIGHT...GRADUAL CLEARING FROM WEST TO EAST AS THE UPPER TROUGH
SHIFTS EAST AND THE FLOW BECOMES ANTI-CYCLONIC. THE SURFACE RIDGE
WILL BE SHIFTING TO OUR SOUTH ALLOWING WINDS TO BACK SOUTHWEST.
TEMPERATURES SHOULDN`T DROP TOO MUCH TONIGHT DUE TO SOUTHWEST WINDS
AND WEAK WARM AIR ADVECTION DEVELOPING. MINIMUM TEMPERATURES ARE
EXPECTED TO BE IN THE LOWER TO MID 20S...WITH THE COOLEST READINGS
IN FAR NW IL WHERE SEVERAL INCHES OF SNOW COVER EXISTS.
FRIDAY...SKIES WILL BE SUNNY IN THE MORNING THEN INCREASING CLOUDS
DURING THE AFTERNOON IN OUR NORTH...AS A WEAK SHORT WAVE DROPS
SOUTHEAST TOWARDS THE AREA IN THE NW FLOW ALOFT. WITH SOUTHWEST SURFACE
WINDS THIS SHOULD BOOST AFTERNOON TEMPERATURES INTO THE UPPER 30S
TO LOWER 40S AT MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CST THU JAN 22 2015
CHANCE OF RAIN/SNOW LATE SAT NGT-SUN...OTHERWISE GENERALLY DRY WITH
TEMP MOSTLY NEAR TO ABOVE NORMAL.
FRIDAY NIGHT... WEAK AND QUICK MOVING UPPER AIR DISTURBANCE TO SWEEP
THROUGH THE GREAT LAKES WITH ATTENDANT SURFACE TROUGH PASSING
ACROSS CWA. WEAK FORCING AND LIMITED MOISTURE SHOULD PRECLUDE MUCH
MORE THAN JUST INCREASING CLOUDS AND POSSIBLY FEW FLURRIES OR PATCHY
DRIZZLE NORTHEAST IA INTO NORTHWEST IL DEPENDING ON ICE INTRODUCTION
AND DEPTH OF MOISTURE. MINIMAL COOLING POST TROUGH COUPLED WITH
CLOUDINESS LENDS SUPPORT FOR STAYING NEAR WARM SIDE OF GUIDANCE ON
LOWS AND GENERALLY IN THE UPPER 20S TO AROUND 30F.
SATURDAY AND SUNDAY... MODELS STILL VARY WITH TRACK OF FAIRLY VIGOROUS
CLIPPER SYSTEM LATE SATURDAY NIGHT ALTHOUGH STARTING TO SEE SOME
TRENDS AND CLUSTERING WITH 12Z MODEL SUITE. MOST NOTABLY THE GEM HAS
TRENDED MUCH FURTHER SOUTH FROM UPPER PENINSULA OF MI TO CENTRAL WI WHICH
IS CLOSER TO TRACK OF UKMET AND OPERATIONAL GFS. THE OPERATIONAL GFS IS
ACTUALLY A LITTLE FURTHER SOUTH OF ENSEMBLE MEAN AND NEARLY ALL OF THE
MEMBERS. MEANWHILE THE ECMWF CONTINUES TO REMAIN THE FURTHEST SOUTH TAKING
THE CLIPPER SYSTEM ACROSS THE CWA. A MORE NORTHEAST TRACK WOULD RESULT
IN TAPERED PCPN CHCS FROM WEST TO EAST WITH RAIN BEING THE MORE DOMINANT
PRECIPITATION TYPE WITH SOME LIGHT SNOW OR FLURRIES POSSIBLE IN
WRAP-AROUND. MEANWHILE A TRACK FURTHER SOUTHWEST SUCH AS SHOWN BY ECMWF
COULD RESULT IN MORE SNOW WITH LIGHT ACCUMULATIONS. WITH THE MAIN SYSTEM
IN QUESTION STILL OFF THE BRITISH COLUMBIA COASTLINE AND NOT WELL SAMPLED
YET BY RAOB NETWORK IT COULD TAKE ANOTHER 12-24 HRS BEFORE THAT OCCURS AND
BEFORE WE START SEEING BETTER MODEL CONSISTENCY WITH THE TRACK. FOR NOW
THOUGH WILL CONTINUE WITH CHANCE OF PCPN OVERNIGHT SATURDAY NIGHT
THROUGH SUNDAY... WITH MAINLY RAIN WITH SOME MIX OF SNOW NORTH TRANSITIONING
TO MIX OR SNOW SUNDAY. FEELING IS A MORE SOUTHERLY TRACK PERHAPS CLOSER
TO ECMWF OR BLENDED WITH GFS REASONABLE. AS PREVIOUS SHIFTS HAVE MENTIONED
THE ORIENTATION OF THE LEFT EXIT REGION OF 150+ KT JET WITH COMPACT
SHORTWAVE TROUGH FAVORS MORE DIGGING OF SYSTEM WHICH FITS CONCEPTUALLY WITH
SYSTEM ENTERING LONGWAVE TROUGH. THIS WOULD SUPPORT MORE SOUTHERLY TRACK
WHICH IS ALSO HINTED BY GFS ENSEMBLE WITH ITS LARGEST STANDARD DEVIATION
IN 500 MB HEIGHTS OVER EASTERN IA/NORTHWEST IL SUNDAY 12Z.
TEMPS SATURDAY AND SUNDAY WILL DEPEND ON TRACK OF CLIPPER SYSTEM... BUT
IN GENERAL MUCH OF THE PERIOD SHOULD BE ABOVE FREEZING AND ABOVE NORMAL
WITH AREA RESIDING IN WARM SECTOR AHEAD OF SYSTEM. EXCEPTION BEING
SUNDAY NIGHT IN WAKE OF DEPARTING SYSTEM AS NORTHERLY WINDS WILL USHER IN
COLDER AIR AND EXPECT LOWS SUNDAY NIGHT TO DIP DOWN WELL INTO THE 20S.
MONDAY THROUGH THURSDAY... MAINLY DRY WITH SOME SUGGESTION OF ANOTHER
CLIPPER SYSTEM AROUND TUESDAY AND POSSIBLY THURSDAY BUT CONFIDENCE ON
TRACK AND IMPACT TOO LOW FOR MENTIONABLE POPS AS IT APPEARS AT THIS TIME.
TEMPS TO TAKE A BIT OF A HIT MONDAY INTO TUESDAY WITH COLDER AIR AND
MAY NEED TO BE LOWERED A BIT MORE CLOSER TO NORMAL WITH ECMWF AND GFS
SHOWING 850 TEMPS AROUND -4C TO -10C FROM WEST TO EAST SUPPORTIVE OF
GRADIENT IN TEMPS AS WELL. ANOTHER ROUND OF MP AIRMASS SHOWN BY GFS AND
ECMWF TO RETURN TO MIDWEST MID-LATE WEEK WHICH SHOULD SEND TEMPS BACK
ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1133 PM CST THU JAN 22 2015
A PERSISTENT DECK OF LOW CLOUDS WITH BASES AROUND 1200 TO 2000 FT
AGL WAS COVERING MOST OF IL AND THE EASTERN HALF OF IA THIS
EVENING...RESULTING IN WIDESPREAD MVFR CONDITIONS. THE BACK EDGE
OF THE CLOUDS OVER CENTRAL IA CONTINUES TO SLOWLY EDGE
EASTWARD...BUT ITS PROGRESS HAS SLOWED SOME THIS EVENING. THE
LATEST FORECASTS HAVE DELAYED THE EXPECTED CLEARING TREND AND
TRANSITION TO VFR CONDITIONS BY SEVERAL HOURS...NOT REACHING CID
UNTIL WELL AFTER MIDNIGHT AND THEN THE MS RIVER SITES CLOSER TO
SUNRISE. VFR CONDITIONS AND INCREASING SOUTHWEST WINDS ARE THEN
EXPECTED FOR THE REMAINDER OF FRIDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...05
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
548 PM CST Sat Jan 24 2015
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Sunday)
Issued at 253 PM CST SAT JAN 24 2015
An upper level trough located across the northern plains this
afternoon will dig southeast into the mid MS river valley by Sunday
Afternoon.
The stronger ascent ahead of this upper level trough will remain
across the northern plains into the Midwest and OH river valley. The
mesoscale models show another area of stronger ascent developing
within the left exit region, ahead of an 80 KT H5 jet max, which
will dig from eastern MT this afternoon, southeast across western
KS, into northeast OK through the night. Both the Advanced Research
and Non-hydrostatic WRF model solutions show an area of light rain
developing across west central KS this evening in the region of the
left exit region of the H5 jet. ATTM, the area of light rain will
move southeast ahead of the H5 jet max and spread southeast across
south central KS into northeast OK through the night. The 12Z GFS
model is the only solution showing the area of steadier light rain
moving across the southern half of the CWA this evening. I will be
leaning more towards the ARW, NMM and HRRR solutions.
Most of the CWA will only see occasional sprinkles or very light
rain showers through the night into the morning hours of Sunday as
the H5 trough axis moves southeast. Forecast soundings continue to
show a drier layer air within the lowest 6,000 feet of the
atmosphere. Overnight lows will be mild with westerly winds of 10 to
20 MPH. Most areas should see overnight lows only dropping into the
upper 30s.
Sunday, as the upper trough amplifies across northern MO, wrap
around rain showers are possible across the northeast and east
central KS. These showers look to be light with only a trace
to 0.01 inch of QPF forecasted. A surface/925mb low will deepen
across northern MO through the day. Northwest winds will increase
through the mid morning hours to 20 to 30 MPH with gusts up to 40
MPH. The southern counties of the CWA may flirt with wind advisory
criteria during the late morning and early afternoon hours. The
low-level CAA will only allow high temperatures to reach the lower
to mid 40s across the eastern half of the CWA, where clouds may
continue through most of the day. The western counties may see some
afternoon insolation which may help highs to reach into the mid to
upper 40s.
.LONG TERM...(Sunday Night through Saturday)
Issued at 253 PM CST SAT JAN 24 2015
Sunday Night through Monday Night ...
By Sunday night, the vertically-stacked surface low and mid-level
low will be situated over the Ohio River Valley with
north-northwesterly flow aloft prevailing across the central U.S. A
narrow ridge of surface high pressure will spill southward into the
forecast area Sunday night into Monday resulting in mostly clear
skies and light winds. As a result, decent radiational cooling will
help drop overnight low temperatures into the mid/upper 20s.
Models show the next surface low positioned over the far northern U.S.
and tracking toward the Great Lakes region through Monday night. An
associated cold front will extend southward across the Northern and
Central Plains Monday morning and is expected to skim southeastward
across the forecast area from late morning through the afternoon
hours. Since this front looks to barely extend far enough south into
the area, there should not be a strong wind shift associated with
this frontal passage. As a result, models show winds gradually
veering from southwest to west-northwest through the day. Soundings
are very dry so don`t even expect much in the way of cloud cover
with this frontal passage. With a thermal ridge in place just west
of the forecast area and decent downslope winds expected, should see
another mild day with high temperatures reaching into the upper 50s
east to middle 60s west. An area of surface high pressure will
advance into the Northern and Central Plains behind the front, with
mostly clear skies and light northwesterly winds resulting in low
temperatures dropping into the low 30s by Tuesday morning.
Tuesday through Saturday Night...
A pattern of benign weather is expected Tuesday through Friday as a
dry forecast remains in place. A wave will push through the area on
Wednesday evening; however, any precipitation associated with this
energy will be to the north of the area. The next mention of
precipitation is Saturday, associated with a shortwave amplifying in
the Rocky Mountains. Two completely different solutions are seen by
the models with the ECMWF proposing energy with this system will
stay well south keeping the area completely dry, while the GFS
solution continues to amplify this wave allowing for a moderate
amount of precipitation. Due to such a robust solution with the
GFS, have put in 20 percent chances for PoPs over the entire area
Saturday, with a chance for both rain and snow. As of right now,
confidence of how this system will play out is low and should
continue to be monitored.
As for temperatures, Tuesday and Wednesday will continue to be above
normal with highs topping out in the upper 50s/lower 60s. A weak
cold front associated with the system on Wednesday will lower
temperatures slightly Thursday and Friday, with highs in the mid 40s
and lows below freezing. Saturday will be even cooler as winds
shift from the north bringing highs back to climatological normals.
&&
.AVIATION...(For the 00Z TAFs through 00Z Sunday Evening)
Issued at 545 PM CST SAT JAN 24 2015
TAF is primarily a wind forecast, with MVFR cigs in the later
period. Initially west winds increase to generally 15-20kts
overnight and into the day Sunday. Winds diminish later in the
afternoon. Showers on radar are more likely virga given dry air in
low levels and will carry VCSH at this time, noting that these
passing virga showers may also bring gusty winds as they pass.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Heller/Hennecke
AVIATION...67
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1044 PM EST SAT JAN 24 2015
.UPDATE...
ISSUED AT 1044 PM EST SAT JAN 24 2015
MOSTLY CLEAR SKIES ARE CURRENTLY BEING SEEN ACROSS EASTERN KENTUCKY
BESIDES SOME SCATTERED HIGHER BASED STRATOCU SKIRTING BY IN THE
NORTH...AS WELL AS THE LAST OF THE LOWER CLOUDS EXITING FAR
SOUTHEASTERN KENTUCKY. THANKS TO THE CLEARING...VALLEYS HAVE DIPPED
INTO THE UPPER 20S IN SPOTS. MID AND HIGH LEVEL CLOUDS WILL BE MOVING
IN AFTER MIDNIGHT...WHICH SHOULD TEMPER THE DROP OFF...HOWEVER HAVE
LOWERED THE COOLER VALLEYS TO AROUND 27 DEGREES GIVEN THE CURRENT
TRENDS. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 711 PM EST SAT JAN 24 2015
A BATCH OF LOW CLOUDS IS CURRENTLY MOVING EAST ACROSS OUR AREA
ASSOCIATED WITH A PASSING SHORT WAVE TROUGH MOVING THROUGH THE OHIO
VALLEY. THE LATEST IR SATELLITE IMAGERY REVEALS A PRETTY DEFINED
BACK EDGE TO THESE CLOUDS...AND THE LATEST RUC DATA SUGGESTS THAT
ONCE THESE EXIT IN THE NEXT FEW HOURS...THAT ADDITIONAL LOW CLOUDS
WILL BE HARDER TO COME BY GIVEN THE WEST TO SOUTHWEST WINDS TO
REMAIN IN PLACE AND A LITTLE SUBSIDENCE TO FOLLOW THE EXITING WAVE.
MID AND HIGH LEVEL CLOUDS WILL LIKELY INCREASE ACROSS THE AREA AFTER
MIDNIGHT OUT AHEAD OF THE NEXT SYSTEM. HAVE LEFT THE LOWS AROUND THE
30 DEGREE MARK IN PLACE FOR NOW...ALTHOUGH WILL HAVE TO KEEP AN EYE
ON SHELTERED VALLEYS THAT MAY DECOUPLE AND TAKE ADVANTAGE OF SOME
EVENTUAL PARTIAL CLEARING. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 415 PM EST SAT JAN 24 2015
CURRENT CONDITIONS ACROSS THE AREA FEATURE SOME EXTENSIVE CLOUD COVER
MOVING SOUTHEAST THROUGH THE AREA ASSOCIATED WITH A WEAK TROUGH. WITH
THIS HAS BEEN SOME LIGHT FLURRY ACTIVITY OR SPRINKLES MAINLY TAKING
AIM OVER THE NORTHEASTERN PORTION OF EASTERN KENTUCKY. WILL KEEP A
MENTION OF FLURRIES AND A POSSIBLE SNOW SHOWER OVER THE AREA AND
ESPECIALLY OVER THE EAST IN MARTIN AND PIKE COUNTY. WITH THIS
FEATURE...CLOUD COVER WILL REMAIN OVER THE AREA THROUGH THIS EVENING
AND THROUGH TONIGHT. THIS HAS KEPT TEMPERATURES SUPPRESSED THROUGH THE
DAY TODAY BUT WITH WINDS OUT OF THE SOUTHWEST REMAINING UP IN MOST
LOCATIONS TONIGHT...WILL LOOK LIKE TEMPS MAY REMAIN STEADY OR SLOWLY
FALL THROUGH THE NIGHT. HOWEVER...SOME CONCERN HERE WILL BE OVER THE
SOUTH WHERE A FEW BREAKS IN THE CLOUD COVER MAY RESULT IN TEMPS
FALLING FURTHER...ESPECIALLY IN THE VALLEYS. AS WELL...SOME CONCERN
FOR PATCHY FOG WAS A POSSIBLE OCCURRENCE TONIGHT WHERE SNOW HAD
FALLEN IN THE NORTH BUT WITH REMAINING CLOUD COVER AND WINDS
SLIGHTLY UP...WILL LIKELY NOT DEVELOP MORE THAN PATCHY INSTANCES IF
AT ALL SO LEFT THIS OUT OF THE FORECAST.
CONCERNING SUNDAY THROUGH MONDAY WITH THE APPROACHING CLIPPER
SYSTEM...MODELS HAVE TRENDED DRY WITH THIS FEATURE AND SLIGHTLY
WARMER BUT WILL STILL SEEM TO BE DEALING WITH SHOWERS FOR SUNDAY AS
THIS FRONT ARRIVES. SOUTHWEST FLOW WILL BRING TEMPERATURES UP INTO
THE 40S DURING THE DAY ON SUNDAY BEFORE THE COLDER AIR MOVES IN
SUNDAY NIGHT. DEALING WITH A CONVECTIVE PROCESS AND THE RIGHT WIND
DIRECTION FOR UPSLOPE FLOW WILL MAKE FOR THE CHANGE OVER TO SNOW BY
LATE SUNDAY NIGHT AND INTO MONDAY...ESPECIALLY IN THE HIGHER
ELEVATIONS. AS THE CASE IN THESE EVENTS...THE DEPTH OF THE MOISTURE
IN THE COLUMN DOES BEGIN TO EXIT COME MONDAY AFTERNOON DURING THE
UPSLOPE PORTION OF THIS EVENT SO SNOWFALL TOTALS WILL BE LIMITED FOR
THE LATE SUNDAY NIGHT THROUGH MONDAY PERIOD. RIGHT NOW THINKING THAT
THE VALLEYS AND THE BLUEGRASS REGION WILL BE UNDER AN INCH TOTAL WITH
MORE THAN AN INCH ABOVE 2000 FEET. WILL MENTION THIS THREAT IN THE
HWO BUT THE OCCURRENCE BEING SUNDAY NIGHT INTO MONDAY MAY REQUIRE SOME
FURTHER CONSIDERATION TO HIGHLIGHT THE IMPACT TO THE MORNING COMMUTE
ON MONDAY.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 PM EST SAT JAN 24 2015
A RATHER ACTIVE PATTERN IS ANTICIPATED THROUGH THE PERIOD. MODELS
WERE IN GENERALLY IN GOOD AGREEMENT AND THE FORECAST WAS KEPT VERY
CLOSE TO THE MODEL CONSENSUS BLEND. AT THE START OF THE
PERIOD...A TROUGH IS EXPECTED TO EXTEND FROM EASTERN CANADA INTO THE
GREAT LAKES REGION AND EASTERN SEABOARD. MEANWHILE A RIDGE IS
EXPECTED TO EXTEND FROM MEXICO NORTH INTO THE ROCKIES. THIS WILL
LEAD TO NW FLOW ALOFT INITIALLY WITH A SERIES OF SHORTWAVES EXPECTED
TO DROP DOWN ACROSS THE LOWER OH VALLEY REGION AND APPALACHIANS. THE
TROUGH AXIS IS EXPECTED TO GRADUALLY MOVE OFF THE EASTERN SEABOARD
BY MIDWEEK...WITH THE RIDGE SHIFTING EAST TO THE PLAINS STATES AND
EVENTUALLY OH VALLEY REGION. HOWEVER...A SHORTWAVE MOVING AROUND THE
RIDGE AND A TROUGH IN THE NORTHERN STREAM WILL BEGIN TO INTERACT
OVER THE PLAINS AT MIDWEEK AND THE RESULTING TROUGH SHOULD DAMPEN
THE RIDGE AND APPROACH THE REGION LATE WED NIGHT. THIS SYSTEM WILL
MOVE ACROSS THE GREAT LAKES AND OH VALLEY REGION ON THU INTO
THURSDAY NIGHT. THE ASSOCIATED SFC LOW IS EXPECTED TO TRACK NORTH OF
THE OH RIVER AND THEN INTO THE NORTHEAST OR MID ATLANTIC STATES.
THIS WOULD BRING THE TRAILING COLD FRONT ACROSS EAST KY ON THU TO THU
EVENING.
FROM FRI INTO SATURDAY..THE MODEL CONSENSUS IS FOR SOME FLATTENING
OF THE FLOW AT LEAST BRIEFLY FROM THE PLAINS INTO THE EASTERN CONUS
THOUGH ANOTHER SHORTWAVE WILL BEGIN TO APPROACH THE AREA LATE IN THE
PERIOD.
THE SHORTWAVES IN NW FLOW SHOULD BRING AT LEAST PERIODS OF CLOUDS OR
PROLONG CLOUDS ACROSS THE REGION WITH THE LOW LEVEL FLOW MAINTAINING
AN UPSLOPE COMPONENT. THERE ARE SOME TIMING DIFFERENCES FOR THE MON
NIGHT TO TUE PERIOD WITH THE 12Z GFS RECENT NAM RUNS ARE ALSO MORE
MOIST THE 12Z ECMWF. SOME LIGHT SNOW OR FLURRIES AS WELL AS SNOW
SHOWERS WILL BE POSSIBLE ESPECIALLY DURING DAYTIME HEATING ON TUE
WHICH WOULD STEEPEN LAPSE RATES. ANY SNOW SHOWERS COULD PRODUCE AT
LEAST SOME LOCALIZED LIGHT AMOUNTS MON NIGHT INTO TUE NIGHT. FOR
POPS DURING THIS PERIOD...WENT A BIT HIGHER THAN THE MODEL BLEND
CLOSER TO PERSISTENCE FROM THE PREVIOUS FORECAST. GENERALLY DRY
WEATHER IS EXPECTED BRIEFLY AT MIDWEEK.
FOR LATE WED NIGHT INTO THU...AT THE ONSET OF THE PRECIPITATION
WETBULBING COULD LEAD TO A MIX WITH SNOW DEPENDING ON HOW QUICKLY IT
ARRIVES. HOWEVER...ANY PRECIPITATION WITH THIS SYSTEM SHOULD REMAIN
AS MOSTLY IF NOT ENTIRELY RAIN UNTIL THE PASSAGE OF THE COLD FRONT.
TEMPERATURES SHOULD AVERAGE BELOW NORMAL FOR TUE INTO WED...BUT THEN
MODERATE TO ABOVE NORMAL ON THU IN BETWEEN SYSTEM UNDER THE
INFLUENCE OF WEAK RIDGING. BEHIND THE SHORTWAVE AND COLD
FRONT...TEMPS SHOULD AGAIN RETURN TO BELOW NORMAL LEVELS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 711 PM EST SAT JAN 24 2015
MVFR STRATOCU DECK LOOKS TO EXIT EAST IN THE NEXT FEW HOURS. VFR
CONDITIONS SHOULD REMAIN IN PLACE GENERALLY THROUGH THE MAJORITY OF
THE REST OF THE FORECAST...ALTHOUGH PRECIPITATION WILL BE THREATENING
WITH LOWERING CEILINGS ONCE AGAIN TOWARDS 00Z MONDAY AS THE NEXT
WEATHER MAKER MOVES IN FROM THE NORTHWEST. WSW WINDS OF 5 TO 10
KTS...WITH A FEW EARLY GUSTS TO AROUND 15 KTS...WILL GENERALLY BACK
TO THE SOUTH SOUTHWEST OVERNIGHT THROUGH SUNDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SHALLENBERGER
LONG TERM...JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
711 PM EST SAT JAN 24 2015
.UPDATE...
ISSUED AT 711 PM EST SAT JAN 24 2015
A BATCH OF LOW CLOUDS IS CURRENTLY MOVING EAST ACROSS OUR AREA
ASSOCIATED WITH A PASSING SHORT WAVE TROUGH MOVING THROUGH THE OHIO
VALLEY. THE LATEST IR SATELLITE IMAGERY REVEALS A PRETTY DEFINED
BACK EDGE TO THESE CLOUDS...AND THE LATEST RUC DATA SUGGESTS THAT
ONCE THESE EXIT IN THE NEXT FEW HOURS...THAT ADDITIONAL LOW CLOUDS
WILL BE HARDER TO COME BY GIVEN THE WEST TO SOUTHWEST WINDS TO
REMAIN IN PLACE AND A LITTLE SUBSIDENCE TO FOLLOW THE EXITING WAVE.
MID AND HIGH LEVEL CLOUDS WILL LIKELY INCREASE ACROSS THE AREA AFTER
MIDNIGHT OUT AHEAD OF THE NEXT SYSTEM. HAVE LEFT THE LOWS AROUND THE
30 DEGREE MARK IN PLACE FOR NOW...ALTHOUGH WILL HAVE TO KEEP AN EYE
ON SHELTERED VALLEYS THAT MAY DECOUPLE AND TAKE ADVANTAGE OF SOME
EVENTUAL PARTIAL CLEARING. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 415 PM EST SAT JAN 24 2015
CURRENT CONDITIONS ACROSS THE AREA FEATURE SOME EXTENSIVE CLOUD COVER
MOVING SOUTHEAST THROUGH THE AREA ASSOCIATED WITH A WEAK TROUGH. WITH
THIS HAS BEEN SOME LIGHT FLURRY ACTIVITY OR SPRINKLES MAINLY TAKING
AIM OVER THE NORTHEASTERN PORTION OF EASTERN KENTUCKY. WILL KEEP A
MENTION OF FLURRIES AND A POSSIBLE SNOW SHOWER OVER THE AREA AND
ESPECIALLY OVER THE EAST IN MARTIN AND PIKE COUNTY. WITH THIS
FEATURE...CLOUD COVER WILL REMAIN OVER THE AREA THROUGH THIS EVENING
AND THROUGH TONIGHT. THIS HAS KEPT TEMPERATURES SUPPRESSED THROUGH THE
DAY TODAY BUT WITH WINDS OUT OF THE SOUTHWEST REMAINING UP IN MOST
LOCATIONS TONIGHT...WILL LOOK LIKE TEMPS MAY REMAIN STEADY OR SLOWLY
FALL THROUGH THE NIGHT. HOWEVER...SOME CONCERN HERE WILL BE OVER THE
SOUTH WHERE A FEW BREAKS IN THE CLOUD COVER MAY RESULT IN TEMPS
FALLING FURTHER...ESPECIALLY IN THE VALLEYS. AS WELL...SOME CONCERN
FOR PATCHY FOG WAS A POSSIBLE OCCURRENCE TONIGHT WHERE SNOW HAD
FALLEN IN THE NORTH BUT WITH REMAINING CLOUD COVER AND WINDS
SLIGHTLY UP...WILL LIKELY NOT DEVELOP MORE THAN PATCHY INSTANCES IF
AT ALL SO LEFT THIS OUT OF THE FORECAST.
CONCERNING SUNDAY THROUGH MONDAY WITH THE APPROACHING CLIPPER
SYSTEM...MODELS HAVE TRENDED DRY WITH THIS FEATURE AND SLIGHTLY
WARMER BUT WILL STILL SEEM TO BE DEALING WITH SHOWERS FOR SUNDAY AS
THIS FRONT ARRIVES. SOUTHWEST FLOW WILL BRING TEMPERATURES UP INTO
THE 40S DURING THE DAY ON SUNDAY BEFORE THE COLDER AIR MOVES IN
SUNDAY NIGHT. DEALING WITH A CONVECTIVE PROCESS AND THE RIGHT WIND
DIRECTION FOR UPSLOPE FLOW WILL MAKE FOR THE CHANGE OVER TO SNOW BY
LATE SUNDAY NIGHT AND INTO MONDAY...ESPECIALLY IN THE HIGHER
ELEVATIONS. AS THE CASE IN THESE EVENTS...THE DEPTH OF THE MOISTURE
IN THE COLUMN DOES BEGIN TO EXIT COME MONDAY AFTERNOON DURING THE
UPSLOPE PORTION OF THIS EVENT SO SNOWFALL TOTALS WILL BE LIMITED FOR
THE LATE SUNDAY NIGHT THROUGH MONDAY PERIOD. RIGHT NOW THINKING THAT
THE VALLEYS AND THE BLUEGRASS REGION WILL BE UNDER AN INCH TOTAL WITH
MORE THAN AN INCH ABOVE 2000 FEET. WILL MENTION THIS THREAT IN THE
HWO BUT THE OCCURRENCE BEING SUNDAY NIGHT INTO MONDAY MAY REQUIRE SOME
FURTHER CONSIDERATION TO HIGHLIGHT THE IMPACT TO THE MORNING COMMUTE
ON MONDAY.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 PM EST SAT JAN 24 2015
A RATHER ACTIVE PATTERN IS ANTICIPATED THROUGH THE PERIOD. MODELS
WERE IN GENERALLY IN GOOD AGREEMENT AND THE FORECAST WAS KEPT VERY
CLOSE TO THE MODEL CONSENSUS BLEND. AT THE START OF THE
PERIOD...A TROUGH IS EXPECTED TO EXTEND FROM EASTERN CANADA INTO THE
GREAT LAKES REGION AND EASTERN SEABOARD. MEANWHILE A RIDGE IS
EXPECTED TO EXTEND FROM MEXICO NORTH INTO THE ROCKIES. THIS WILL
LEAD TO NW FLOW ALOFT INITIALLY WITH A SERIES OF SHORTWAVES EXPECTED
TO DROP DOWN ACROSS THE LOWER OH VALLEY REGION AND APPALACHIANS. THE
TROUGH AXIS IS EXPECTED TO GRADUALLY MOVE OFF THE EASTERN SEABOARD
BY MIDWEEK...WITH THE RIDGE SHIFTING EAST TO THE PLAINS STATES AND
EVENTUALLY OH VALLEY REGION. HOWEVER...A SHORTWAVE MOVING AROUND THE
RIDGE AND A TROUGH IN THE NORTHERN STREAM WILL BEGIN TO INTERACT
OVER THE PLAINS AT MIDWEEK AND THE RESULTING TROUGH SHOULD DAMPEN
THE RIDGE AND APPROACH THE REGION LATE WED NIGHT. THIS SYSTEM WILL
MOVE ACROSS THE GREAT LAKES AND OH VALLEY REGION ON THU INTO
THURSDAY NIGHT. THE ASSOCIATED SFC LOW IS EXPECTED TO TRACK NORTH OF
THE OH RIVER AND THEN INTO THE NORTHEAST OR MID ATLANTIC STATES.
THIS WOULD BRING THE TRAILING COLD FRONT ACROSS EAST KY ON THU TO THU
EVENING.
FROM FRI INTO SATURDAY..THE MODEL CONSENSUS IS FOR SOME FLATTENING
OF THE FLOW AT LEAST BRIEFLY FROM THE PLAINS INTO THE EASTERN CONUS
THOUGH ANOTHER SHORTWAVE WILL BEGIN TO APPROACH THE AREA LATE IN THE
PERIOD.
THE SHORTWAVES IN NW FLOW SHOULD BRING AT LEAST PERIODS OF CLOUDS OR
PROLONG CLOUDS ACROSS THE REGION WITH THE LOW LEVEL FLOW MAINTAINING
AN UPSLOPE COMPONENT. THERE ARE SOME TIMING DIFFERENCES FOR THE MON
NIGHT TO TUE PERIOD WITH THE 12Z GFS RECENT NAM RUNS ARE ALSO MORE
MOIST THE 12Z ECMWF. SOME LIGHT SNOW OR FLURRIES AS WELL AS SNOW
SHOWERS WILL BE POSSIBLE ESPECIALLY DURING DAYTIME HEATING ON TUE
WHICH WOULD STEEPEN LAPSE RATES. ANY SNOW SHOWERS COULD PRODUCE AT
LEAST SOME LOCALIZED LIGHT AMOUNTS MON NIGHT INTO TUE NIGHT. FOR
POPS DURING THIS PERIOD...WENT A BIT HIGHER THAN THE MODEL BLEND
CLOSER TO PERSISTENCE FROM THE PREVIOUS FORECAST. GENERALLY DRY
WEATHER IS EXPECTED BRIEFLY AT MIDWEEK.
FOR LATE WED NIGHT INTO THU...AT THE ONSET OF THE PRECIPITATION
WETBULBING COULD LEAD TO A MIX WITH SNOW DEPENDING ON HOW QUICKLY IT
ARRIVES. HOWEVER...ANY PRECIPITATION WITH THIS SYSTEM SHOULD REMAIN
AS MOSTLY IF NOT ENTIRELY RAIN UNTIL THE PASSAGE OF THE COLD FRONT.
TEMPERATURES SHOULD AVERAGE BELOW NORMAL FOR TUE INTO WED...BUT THEN
MODERATE TO ABOVE NORMAL ON THU IN BETWEEN SYSTEM UNDER THE
INFLUENCE OF WEAK RIDGING. BEHIND THE SHORTWAVE AND COLD
FRONT...TEMPS SHOULD AGAIN RETURN TO BELOW NORMAL LEVELS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 711 PM EST SAT JAN 24 2015
MVFR STRATOCU DECK LOOKS TO EXIT EAST IN THE NEXT FEW HOURS. VFR
CONDITIONS SHOULD REMAIN IN PLACE GENERALLY THROUGH THE MAJORITY OF
THE REST OF THE FORECAST...ALTHOUGH PRECIPITATION WILL BE THREATENING
WITH LOWERING CEILINGS ONCE AGAIN TOWARDS 00Z MONDAY AS THE NEXT
WEATHER MAKER MOVES IN FROM THE NORTHWEST. WSW WINDS OF 5 TO 10
KTS...WITH A FEW EARLY GUSTS TO AROUND 15 KTS...WILL GENERALLY BACK
TO THE SOUTH SOUTHWEST OVERNIGHT THROUGH SUNDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SHALLENBERGER
LONG TERM...JP
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1033 AM CST FRI JAN 23 2015
.DISCUSSION...
KSHV RADAR CONTINUES TO SHOW PATCHY AREAS OF LIGHT RAIN AND
DRIZZLE...POSSIBLY MIXED WITH A FEW SLEET PELLETS/SNOW GRAINS.
THIS IS EXPECTED FOR MUCH OF THE DAY...AS A POSITIVELY TILTED
UPPER TROF MOVES ACROSS TX. WE SHOULD SEE THIS PRECIP TAPER OFF
TODAY...AS THE TROF CONTINUES EWD AND THE MOISTURE SUPPLY BECOMES
CUT OFF. FOR THE UPDATE...THE GRIDS ARE IN GOOD SHAPE FOR THE MOST
PART. HAVE TWEAKED THE SKY GRIDS TO ACCOUNT FOR THE PATCHY
CLEARING ACROSS OUR NWRN AREAS. OTHERWISE...NO OTHER CHANGES ARE
EXPECTED ATTM. /12/
&&
.PREV DISCUSSION... /ISSUED 539 AM CST FRI JAN 23 2015/
AVIATION...
IFR/LIFR CEILINGS WITH -RA TO PERSIST ACROSS AREA TERMINALS
THROUGH 23/18Z WITH GRADUAL IMPROVEMENT TO VFR FROM THE WEST
THROUGH 24/00Z. OTHERWISE...NORTHWEST WINDS 10 KNOTS WITH HIGHER
GUSTS TO GRADUALLY DIMINISH THROUGHOUT THE DAY...BECOMING WEST AT
5 KNOTS OVERNIGHT. /05/
PREV DISCUSSION... /ISSUED 416 AM CST FRI JAN 23 2015/
DISCUSSION...
COLD CORE UPPER TROUGH IS WELL WEST OF THE AREA BUT IT SHOULD MOVE
ACROSS THE CWA THIS EVENING/TONIGHT. DRY SLOTTING IS ALREADY
OCCURRING AND THE MANY OF THE MODELS HAVE NOT HANDLED IT VERY WELL.
THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE PRECIP KEEPING THE
VAST MAJORITY OF IT SE OF A KJSO-KELD LINE. THIS IS SUPPORTED BY
THE LATEST RADAR IMAGES WHICH SHOW THE NEXT ROUND OF RAIN ALONG
THE I-10 CORRIDOR HEADING NEWD TOWARDS THE AREA. SCATTERED AREAS
OF LIGHT RAIN ARE ONGOING THIS MORNING AND WILL LIKELY PERSIST AS
FAR NORTH AS I-30 AS DRIER AIR SLOWLY WORKS IN FROM THE NORTH.
MOST OF THE ATMOSPHERE IS BELOW FREEZING WITH THE EXCEPTION OF THE
LOWEST 2000 FEET OR SO AND SFC TEMPS ARE STILL AROUND 40 DEGREES F.
ANY SNOW THAT MAY BE FALLING WILL MOST LIKELY MELT IN THIS LOWEST
LAYER PRIOR TO REACHING THE SFC. LATEST OBS ARE SHOWING SOME
LOCATIONS IN E TX HAVE COOLED INTO THE MID 30S. THEREFORE...A FEW
FLURRIES CANNOT BE COMPLETELY RULED OUT THIS MORNING...MAINLY
NORTH OF A LINE FROM TYLER AND MARSHALL TX TO MAGNOLIA AR...BUT WITH
SFC TEMPERATURES REMAINING ABOVE FREEZING NO ACCUMULATIONS AND NO
IMPACTS ARE ANTICIPATED. ANY WINTRY PRECIP WILL TRANSITION BACK TO
ALL LIQUID RAIN LATER THIS MORNING AND THE PRECIP SHOULD MOVE EAST
AND OUT OF THE CWA THIS EVENING.
CLEARING SKIES TONIGHT COMBINED WITH COLD AND DRY AIR SHOULD
ALLOW FOR A CHILLY NIGHT TONIGHT/SATURDAY MORNING. OVERNIGHT LOWS
ALONG AND NORTH OF I-20 WILL LIKELY BE NEAR OR BELOW FREEZING. WLY
WINDS AND ABUNDANT SUNSHINE SHOULD LEAD TO A QUICK WARMING TREND
WITH DAYTIME HIGHS ABOVE 60 DEGREES AREAWIDE. NWLY FLOW ALOFT WILL
BRING THE NEXT COLD FRONT INTO THE AREA LATE MONDAY/EARLY TUESDAY.
HARDLY ANY COLD AIR ADVECTION IS EXPECTED WITH THE FRONT SO THE
ONLY REAL EFFECT ON TEMPS WILL BE TO HALT THE WARMING TREND AND
GENERALLY HOLD DAYTIME HIGHS IN THE 60S.
AN UPPER RIDGE WILL BUILD OVER THE REGION KEEPING A PERSISTENCE
FCST IN PLACE FOR MUCH OF NEXT WEEK WITH WARM AND DRY CONDITIONS
EXPECTED. THE RIDGE WILL MOVE EAST LATE NEXT WEEK AND OUR NEXT
RAIN CHANCES WILL LIKELY BE NEXT FRIDAY AND INTO THE WEEKEND AS
THE FLOW ALOFT TRANSITION BACK TO NWLY AND A COLD FRONT MOVES INTO
THE CWA AND BECOMES STATIONARY. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 44 32 57 37 65 / 50 10 0 0 0
MLU 43 32 57 37 64 / 50 30 0 0 0
DEQ 48 28 57 33 62 / 20 0 0 0 0
TXK 46 31 56 36 63 / 40 10 0 0 0
ELD 43 31 57 36 62 / 50 20 0 0 0
TYR 47 33 57 37 65 / 40 10 0 0 0
GGG 45 32 57 36 65 / 40 10 0 0 0
LFK 45 35 59 37 65 / 50 10 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
416 AM CST FRI JAN 23 2015
.DISCUSSION...
COLD CORE UPPER TROUGH IS WELL WEST OF THE AREA BUT IT SHOULD MOVE
ACROSS THE CWA THIS EVENING/TONIGHT. DRY SLOTTING IS ALREADY
OCCURRING AND THE MANY OF THE MODELS HAVE NOT HANDLED IT VERY WELL.
THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE PRECIP KEEPING THE
VAST MAJORITY OF IT SE OF A KJSO-KELD LINE. THIS IS SUPPORTED BY
THE LATEST RADAR IMAGES WHICH SHOW THE NEXT ROUND OF RAIN ALONG
THE I-10 CORRIDOR HEADING NEWD TOWARDS THE AREA. SCATTERED AREAS
OF LIGHT RAIN ARE ONGOING THIS MORNING AND WILL LIKELY PERSIST AS
FAR NORTH AS I-30 AS DRIER AIR SLOWLY WORKS IN FROM THE NORTH.
MOST OF THE ATMOSPHERE IS BELOW FREEZING WITH THE EXCEPTION OF THE
LOWEST 2000 FEET OR SO AND SFC TEMPS ARE STILL AROUND 40 DEGREES F.
ANY SNOW THAT MAY BE FALLING WILL MOST LIKELY MELT IN THIS LOWEST
LAYER PRIOR TO REACHING THE SFC. LATEST OBS ARE SHOWING SOME
LOCATIONS IN E TX HAVE COOLED INTO THE MID 30S. THEREFORE...A FEW
FLURRIES CANNOT BE COMPLETELY RULED OUT THIS MORNING...MAINLY
NORTH OF A LINE FROM TYLER AND MARSHALL TX TO MAGNOLIA AR...BUT WITH
SFC TEMPERATURES REMAINING ABOVE FREEZING NO ACCUMULATIONS AND NO
IMPACTS ARE ANTICIPATED. ANY WINTRY PRECIP WILL TRANSITION BACK TO
ALL LIQUID RAIN LATER THIS MORNING AND THE PRECIP SHOULD MOVE EAST
AND OUT OF THE CWA THIS EVENING.
CLEARING SKIES TONIGHT COMBINED WITH COLD AND DRY AIR SHOULD
ALLOW FOR A CHILLY NIGHT TONIGHT/SATURDAY MORNING. OVERNIGHT LOWS
ALONG AND NORTH OF I-20 WILL LIKELY BE NEAR OR BELOW FREEZING. WLY
WINDS AND ABUNDANT SUNSHINE SHOULD LEAD TO A QUICK WARMING TREND
WITH DAYTIME HIGHS ABOVE 60 DEGREES AREAWIDE. NWLY FLOW ALOFT WILL
BRING THE NEXT COLD FRONT INTO THE AREA LATE MONDAY/EARLY TUESDAY.
HARDLY ANY COLD AIR ADVECTION IS EXPECTED WITH THE FRONT SO THE
ONLY REAL EFFECT ON TEMPS WILL BE TO HALT THE WARMING TREND AND
GENERALLY HOLD DAYTIME HIGHS IN THE 60S.
AN UPPER RIDGE WILL BUILD OVER THE REGION KEEPING A PERSISTENCE
FCST IN PLACE FOR MUCH OF NEXT WEEK WITH WARM AND DRY CONDITIONS
EXPECTED. THE RIDGE WILL MOVE EAST LATE NEXT WEEK AND OUR NEXT
RAIN CHANCES WILL LIKELY BE NEXT FRIDAY AND INTO THE WEEKEND AS
THE FLOW ALOFT TRANSITION BACK TO NWLY AND A COLD FRONT MOVES INTO
THE CWA AND BECOMES STATIONARY. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 44 32 57 37 65 / 50 10 0 0 0
MLU 43 32 57 37 64 / 50 30 0 0 0
DEQ 48 28 57 33 62 / 20 0 0 0 0
TXK 46 31 56 36 63 / 40 10 0 0 0
ELD 43 31 57 36 62 / 50 20 0 0 0
TYR 47 33 57 37 65 / 40 10 0 0 0
GGG 45 32 57 36 65 / 40 10 0 0 0
LFK 45 35 59 37 65 / 50 10 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1146 PM CST THU JAN 22 2015
.AVIATION...GUMBO WEATHER CONTINUES WITH RAIN TAPERING OFF BUT IFR
CIGS ONLY GRADUALLY IMPROVING TO MVFR IN THE COLD WRAP IN THE WAKE
OF THE LOW OUT OVER THE GULF ABOUT TO HEAD EAST OF ACADIANA. COLD
ADVECTION WILL KEEP GUSTY NORTHERLY WINDS THRU FRIDAY. STILL
HOLDING OUT FOR VFR AT BPT AND LCH BY SUNDOWN FRIDAY.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 950 PM CST THU JAN 22 2015/
DISCUSSION...
REGIONAL 88DS SHOW THE BULK OF THE MODERATE/HEAVY RAINS NOW
PUSHING EAST OF THE FORECAST AREA..WITH MAYBE THE LOWER ACADIANA
ZONES STILL SEEING A LITTLE BIT OF HEAVIER PRECIP. ALL THIS WILL
CONTINUE PUSHING EWD ALONG WITH THE SFC LOW OVER THE NRN GULF...
NOW LOCATED SE OF CAMERON. BEHIND THE LARGE AREA OF RAIN REGIONAL
88DS SHOW JUST SPORADIC PATCHY LIGHT RAIN...ALTHOUGH IT CAN
CERTAINLY BE ASSUMED THAT AREAS OF DRIZZLE ARE OCCURRING WITHIN
SUCH AN EXPANSIVE STRATUS OVERCAST NOTED IN SFC OBS ACROSS THE
REGION AHEAD OF THE APPROACHING STORM SYSTEM ALOFT NOW MOVING INTO
WRN TX. BASED ON ALL THIS LOWERED POPS SOMEWHAT FOR THE REMAINDER
OF THE NIGHT...ALTHOUGH RETAINED CATEGORICAL POPS FOR THE SERN
ZONES THROUGH MIDNIGHT. ELSEWHERE JUST MINOR TWEAKS AT MOST TO THE
INHERITED GRIDS/ZONES.
UPDATE OUT SHORTLY.
25
PREV DISCUSSION... /ISSUED 547 PM CST THU JAN 22 2015/
AVIATION...RAIN WITH GUSTY WINDS AND IFR CONDITIONS CAN BE
EXPECTED TO CONTINUE FOR THE WESTERN TERMINALS BPT, LCH AND AEX.
IFR DUE TO VIS AT TIMES AT ARA AND LFT WITH PREDOMINANT MVFR.
ALL THIS DUE TO THE FRONTAL WAVE CURRENTLY APPROACHING THE UPPER
TEXAS COAST WITH A TIGHT GRADIENT PRODUCING GUSTY NORTHEAST WINDS.
RAIN SHOULD TAPER OFF TO VCSH AROUND MID MORNING FRIDAY AND END ABOUT
SUNDOWN FRIDAY WITH VFR AS THE FRONTAL WAVE PULLS UP THE EASTERN
SEABOAARD AND DRY AIR MOVES IN FROM THE NORTHWEST.
SWEENEY
PREV DISCUSSION... /ISSUED 317 PM CST THU JAN 22 2015/
DISCUSSION...
BROAD AREA OF RAIN COVERING OUR ENTIRE COUNTY WARNING AREA THIS
AFTERNOON. TEMPERATURES NOW HOVERING IN THE MID 40S TO LOWER 50S.
OUR 100 PERCENT POP FORECAST LOOKING RIGHT ON THE MONEY...SO A JOB
WELL DONE TO OUR STAFF.
ON THE LARGER CANVAS...IN THE UPPER LEVELS...A TROUGH OF LOW
PRESSURE IS CURRENTLY WORKING ACROSS WEST TEXAS WITH AN ABUNDANCE OF
ENERGY RIDING THROUGH OUR AREA AT THE MOMENT. THIS HAS SPAWNED AN
ELONGATED AREA OF SURFACE LOW PRESSURE OFF THE TEXAS OFFSHORE COASTAL
WATERS FROM BAFFIN BAY TO GALVESTON. MASSIVE AMOUNTS OF GULF
MOISTURE TRAPPED ALONG THE SOUTHEAST TEXAS & LOUISIANA COASTAL
WATERS IN A VERY RICH CONVERGENCE ZONE WHERE LARGE SWATHS OF RAIN
ARE BEING CREATED AND THEN MOVED INLAND.
OBVIOUSLY...THIS IS GOING TO CREATE A VERY GENEROUS AMOUNT OF 1 1/2
TO 2 INCH RAIN AMOUNTS WITH ISOLATED AMOUNTS UP TO THREE INCHES. THE RAIN
WILL BE HERE TO STAY THROUGH THE NIGHT AS OUR HRRR & GFS MODELS
SHOWING OUR NEWLY BORN SURFACE LOW MOVING WEST TO EAST ACROSS OUR
NORTHWEST GULF OF MEXICO THROUGH EARLY MORNING FRIDAY. I RAISED THE
WIND ADVISORY TODAY THROUGH MIDNIGHT FOR I-10 CORRIDOR SOUTH
BECAUSE THIS SURFACE LOW WILL TIGHTEN UP THE WIND FIELD ACROSS OUR
COASTAL AREAS WITH SOME GUSTS AT TIMES FURTHER NORTH AT LEAST
UNTIL MIDNIGHT.
SO...ELEVATED WINDS ARE GOING TO BE A PROBLEM UNTIL MIDNIGHT ALONG
THE COASTAL AREAS AND THE RAINS ARE GOING TO BE THE BIGGEST
PROBLEMS FOR THE ENTIRE AREA OVER THE NEXT 24 HOURS. THE SURFACE
LOW WILL MOVE EAST OF OUR AREA BY NOON FRIDAY...HOWEVER WE WILL
CONTINUE TO EXPECT LIGHT RAIN OR SHOWERS THROUGH THE AFTERNOON
FRIDAY AS THE UPPER LEVEL SYSTEM TRACKS EVEN CLOSER TO US.
RAIN SHOULD EXIT THE ENTIRE AREA BY FRIDAY NIGHT WITH HIGH
PRESSURE BUILDING BACK INTO THE AREA. THE REST OF THE FORECAST
THROUGH DAY SEVEN LOOKS DRY WITH COOL TEMPERATURES THROUGH SUNDAY
MORNING WITH A SLOW WARM-UP FOR THE REST OF NEXT WEEK.
MARINE...
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM FRIDAY AS SOUTHEAST
FLOW THIS AFTERNOON TRANSITIONS TO A NORTHERLY FLOW LATER TONIGHT
WITH THE PASSAGE OF A NORTHWEST GULF SURFACE LOW.
06
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 44 48 37 57 39 / 100 30 20 10 0
KBPT 44 49 37 58 40 / 100 30 10 0 0
KAEX 41 45 34 56 36 / 100 40 20 0 0
KLFT 46 48 38 56 39 / 100 30 20 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: ACADIA...CALCASIEU...EAST CAMERON...IBERIA...
JEFFERSON DAVIS...LAFAYETTE...LOWER ST. MARTIN...ST. MARY...
UPPER ST. MARTIN...VERMILION...WEST CAMERON.
TX...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT
20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA
OUT 20 NM...COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY LA OUT 20 NM...WATERS FROM INTRACOASTAL
CITY TO CAMERON LA FROM 20 TO 60 NM...WATERS FROM CAMERON
LA TO HIGH ISLAND TX FROM 20 TO 60 NM...WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM.
SMALL CRAFT EXERCISE CAUTION UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION
BAY.
&&
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&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1155 PM EST THU JAN 22 2015
.AVIATION...
A REDUCTION IN THE COVERAGE OF STRATUS FROM THE NORTH WILL PROVIDE
POINTS FROM AT LEAST PTK NORTHWARD WITH A PERIOD OF VFR/CLEAR SKY
DURING THE EARLY MORNING PERIOD. A HIGHER DEGREE OF CLOUD COVER MAY
EXIST ACROSS THE DETROIT CORRIDOR AS SOUTHWEST FLOW PROVIDES SOME
RENEWED MOISTURE ADVECTION. THIS PROCESS WILL WORK TOWARD EXPANDING
THE STRATUS BACK NORTHWARD INTO FRIDAY. CONFIDENCE REMAINS ON THE
LOWER SIDE WITH BOTH THE OVERALL COVERAGE AND TIMING ON FRIDAY.
FOR DTW...METRO AIRSPACE CURRENTLY RESIDING ALONG THE FRINGE OF THE
EXISTING MVFR STRATUS DECK. LOWER CONFIDENCE GOING FORWARD GIVEN
RECENT VARIABILITY IN POSITIONING OF THIS CLOUD COVER AS THE FLOW
DEEPENS OUT OF THE SOUTHWEST. RECENT TRENDS WOULD SUGGEST THE
POTENTIAL IS HIGH ENOUGH TO INCLUDE A PERIOD OF VFR EARLY THIS
MORNING.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR CEILING BELOW 5000 FEET TONIGHT AND FRIDAY.
&&
.PREV DISCUSSION...ISSUED 347 PM EST THU JAN 22 2015
SHORT TERM... THROUGH TONIGHT
MAIN FORECAST CHALLENGE IS WITH CLOUD COVER OVERNIGHT. SPLIT FLOW
PATTERN IN PLACE OVER NORTH AMERICA WITH SOUTHEAST MICHIGAN
POSITIONED IN THE POLEWARD ENTRANCE REGION OF A STRONG JET AXIS OVER
THE OHIO VALLEY. THIS WILL PROMOTE ACTIVE SUBSIDENCE THROUGH THE
PERIOD...AS EVIDENCED BY SPRAWLING SURFACE HIGH OVER THE WESTERN
GREAT LAKES. EXTENSIVE STRATUS DECK OVER THE UPPER MIDWEST HAS SHOWN
GOOD SIGNS OF CLEARING OVER WISCONSIN/UPPER MICHIGAN WITH BACK EDGE
OF THE STRATUS WORKING INTO NORTHERN MICHIGAN AND ACROSS LAKE
MICHIGAN. LINEAR EXTRAPOLATION OF THIS CLEARING WOULD WORK IT INTO
SOUTHEAST MICHIGAN AFTER 00Z. HOWEVER...CLIMATOLOGY IS A FACTOR
WORKING AGAINST CLEARING. NAM AND RAP RH PROGS ARE NOT MUCH HELP
HERE AS THEY DID NOT SHOW THE AREA OF CLEARING TO OUR WEST...HOWEVER
THEY DO SHOW POCKETS OF CLEARING OVER THE UPPER MIDWEST OVERNIGHT.
THE UPSHOT IS...TRENDED A BIT MORE OPTIMISTIC WITH CLOUD COVER THAN
PREVIOUS FORECAST...BUT KEPT PARTLY TO MOSTLY CLOUDY SKIES IN ORDER
THAT THE FORECAST NOT BOUNCE AROUND TOO MUCH AS CONFIDENCE IN
CLEARING SKIES IS STILL NOT HIGH.
CLOUD COVER WILL IMPACT LOW TEMPS AS WELL. SIDED WITH THE WARMER MET
MOS. SOME ROOM FOR TEMPS TO DROP BELOW FORECAST LOWS IF CLEARING IS
REALIZED...HOWEVER STILL THINK MAV MOS IS A BIT TOO LOW AS IT IS
UNDERDOING SURFACE DEWPOINTS. ALSO...INCREASING SW GRADIENT FLOW
TOWARD THE END OF THE FORECAST PERIOD SHOULD LIMIT POTENTIAL TEMP
DROP OVER NORTHERN PARTS OF THE FORECAST AREA. THE INCREASED
PRESSURE GRADIENT WILL OCCUR AS AN EXPANSIVE CYCLONE DEEPENS OVER
NORTHERN ONTARIO.
LONG TERM...FRIDAY THROUGH WEDNESDAY
UPPER LEVEL PATTERN BECOMES QUITE COMPLEX TO END THE WEEK. AMPLIFIED
RIDGING OVER THE WESTERN CONUS GET FOLDED OVER IN THE GREAT LAKES
FRIDAY WHICH TRIES TO PINCH OFF THE BASE OF THE TROUGH OVER THE FOUR
CORNERS. ENERGETIC SOUTHERN STREAM KEEPS IT FAIRLY PROGRESSIVE
PREVENTING A TRUE CUTOFF LOW FROM FORMING AS IT TRACKS ACROSS THE
SOUTHERN STATES. INCOMING NORTHERN STREAM ENERGY EVENTUALLY CARVES
OUT ANOTHER DOMINATE TROUGH BY THE END OF THE WEEKEND. AT THE
SFC...HIGH PRESSURE STRUNG OUT FROM THE CENTRAL PLAINS THROUGH THE
OHIO VALLEY AND TO THE EAST COAST ON FRIDAY WILL GET COMPRESSED
BETWEEN NORTHERN STREAM LOW TRACKING THROUGH NORTHERN ONTARIO AND
DEVELOPING SOUTHERN STREAM LOW UNDER THE AFOREMENTIONED PINCHED OFF
TROUGH. THE HIGH WILL MOVE OFF TO THE EAST BY SATURDAY AS THE
SYSTEMS DRAW NEARER EACH OTHER WITH THE ATTEMPTED PHASING OF THE
JETS. OVERALL THIS YIELDS A SOMEWHAT LOWER CONFIDENCE FORECAST AS
SLIGHT DIFFERENCES IN TIMING OF PHASING JETS OR LOCATION OF THE SFC
FEATURES USUALLY LEADS TO JUMPS IN THE FORECAST. LUCKILY IN THIS
CASE...THE PHASING IS ADVERTISED FAR ENOUGH DOWN STREAM TO NEGATE SOME
OF THE TYPICAL CONCERNS.
FOR FRIDAY...WITH HIGH PRESSURE LOCKED AT THE SFC...THE LOW PASSING
THROUGH ONTARIO WILL DROP A COLD FRONT/TROUGH THROUGH LOWER MI IN
THE AFTERNOON. WITH THE HIGH SLIDING TO OUR EAST...WINDS WILL BECOME
SOUTHWESTERLY IN THE MORNING AHEAD OF THE TROUGH AS THE RIDGE AND
TROUGH TIGHTEN THE PRESSURE GRADIENT OVER THE STATE. THESE SW WINDS
WILL BRING THE NOSE OF A THERMAL RIDGE INTO THE AREA THROUGH THE
AFTERNOON. THE WARM AIR WILL STEEPEN THE INVERSION BETWEEN 950-900MB
AS IT WARMS THE LAYER BETWEEN 700 AND 900MB. SO LOOK FOR ELEVATED
WINDS AROUND 15-20MPH WITH GUSTS TO AROUND 25MPH PEAKING IN THE
AFTERNOON. THE STOUT INVERSION WILL PREVENT BETTER MIXING FROM
BRINGING SOME OF THE HIGHER WINDS RIGHT ABOVE THE INVERSION DOWN TO
THE SFC.
THE WEAKENING COLD FRONT WILL ENTER CENTRAL MI AROUND MIDNIGHT WHICH
WILL BRING A CHANCE OF SNOW SHOWERS TO THE SAGINAW VALLEY AND
NORTHERN THUMB. MOISTURE POOLING AHEAD OF THE TROUGH IS DECENT WITH
PWATS INCREASING FROM UNDER 0.2 TO AROUND 0.5 INCHES. THE RIBBON OF
THETA E ALONG THE FRONT IS VERY NARROW WITH A GOOD GRADIENT ON THE
LEAD EDGE INITIALLY...BUT WEAKENING AS IT TRACKS THROUGH SOUTHERN
MI. SEE NO REASON TO DEVIATE FROM THE CHANCE/SLIGHT CHANCE POPS
RIGHT NOW FOR FRIDAY NIGHT. SEVERAL OTHER SMALL WAVES ARE ADVERTISED
TO SHOOT THROUGH THE DEVELOPING NW FLOW KEEPING LOW CHANCE POPS
THROUGH THE DAY SATURDAY. A SECOND...STRONGER COLD FRONT WILL DROP
INTO LOWER MI SATURDAY NIGHT STALLING ACROSS THE AREA AS THE
TRANSITION TO NW FLOW CONTINUES. WITH BL MOISTURE STILL PREVALENT
AND THE FRONT DRAPED ACROSS THE REGION WITH DECENT LAPSE RATES
THROUGH 800MB...WILL HOLD ONTO SOME LOW POP SNOW SHOWER MENTION
THROUGH SAT NIGHT.
CLIPPER DROPS OUT OF MANITOBA AND BEGINS INFLUENCING CONDITIONS
LATE SATURDAY NIGHT THROUGH SUNDAY. THIS SYSTEM COULD BRING IN
ANOTHER SHOT AT ACCUMULATING SNOW SUNDAY INTO EARLY MONDAY MORNING.
COLD AIR ADVECTION BEHIND THE FRONT ON MONDAY IS EXPECTED TO DROP
DAYTIME HIGH`S INTO THE TEENS AND LOW 20`S WITH SINGLE DIGIT
OVERNIGHT LOWS RETURNING FOR BOTH TUESDAY AND WEDNESDAY MORNING.
SCATTERED LIGHT SNOW SHOWERS WILL BE POSSIBLE ON THURSDAY AS ANOTHER
CLIPPER SWINGS THROUGH. TEMPS WARMING INTO THE LOW 30`S DURING THE
DAYLIGHT HOURS FOR THURSDAY AND FRIDAY.
MARINE...
A LOW PRESSURE SYSTEM TRACKING THROUGH CENTRAL CANADA WILL REACH
NORTHERN QUEBEC FRIDAY AFTERNOON. THIS SYSTEM WILL DROP A WEAKENING
COLD FRONT INTO THE REGION FRIDAY. THIS WILL TIGHTEN THE PRESSURE
GRADIENT BETWEEN IT AND THE EXITING SURFACE HIGH ALLOWING WINDS TO
AMPLIFY SOMEWHAT OVER CENTRAL AND NORTHERN LAKE HURON. THOUGH
SUSTAINED WINDS APPEAR TO REACH INTO THE MID 20 KNOT RANGE...WARM
AIR ALOFT AND A STEEP LOW LEVEL INVERSION APPEAR PREVENT STRONGER
GUSTS FROM REACHING THE SURFACE. FEEL FAIRLY CONFIDENT THAT WINDS
WILL GUST AT OR JUST ABOVE 30 KNOTS ACROSS NORTHERN AND CENTRAL LAKE
HURON. THOUGH GALE FORCE GUSTS CANNOT BE RULES OUT
ENTIRELY...CURRENT MODELS AND ANALYSIS SUGGEST WINDS TO THIS
STRENGTH WOULD BE QUITE SPORADIC...AND NOT WIDE SPREAD ENOUGH TO
WARRANT A GALE WARNING OR CONTINUING THE WATCH AT THIS TIME SO THE
WATCH HAS BEEN CANCELLED. EXTENSIVE ICE COVER IN THE LAKE HURON
NEARSHORE ZONES WILL PREVENT ANY WAVES DEVELOPING WITH THE OFFSHORE
FLOW TO AROUND 25 KNOTS...SO SMALL CRAFT ADVISORIES WILL NOT BE
NEEDED AT THIS TIME. COLD NORTHWEST FLOW THIS WEEKEND WILL KEEP
WINDS ELEVATED THROUGH THAT PERIOD...BUT WILL REMAIN BELOW GALE
FORCE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
SHORT TERM...DT
LONG TERM....DRK/DE
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1205 PM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST FRI JAN 23 2015
SHORT TERM CONCERN REMAINS THE THREAT OF FREEZING RAIN/SLEET MOVING
ACROSS THE NORTHERN AND EASTERN CWA MAINLY THROUGH THIS MORNING.
CURRENT RADAR TRENDS INDICATE MODELS MAY BE DOWNPLAYING EXTENT OF
FREEZING RAIN THREAT. WILL FOLLOW A COMBO RAP ISENTROPIC
ANALYSIS (290K/295K LAYERS) AND HRRR TREND FOR POPS THIS AM.
STILL LOOKS THE BEST THREAT REMAINS ALONG AND NORTH OF THE I94
CORRIDOR. WILL LET THE ADV EXPIRE TO THE FAR WEST THROUGH 15Z AND
IN THE EAST BY 18Z. ROAD TEMPERATURE ARE CURRENTLY AROUND 30F IN
THE NORTHERN CWA AND COOLER INTO THE SOUTHERN PORTION OF THE AREA.
SURFACE DEWPTS ARE IN THE LOWER 20S TO THE SOUTH WILL BOTH HELP
AND HINDER FREEZING RAIN THREAT. MAY TAKE SOME TIME TO SATURATE
THE FARTHER SOUTH THE AREA OF PRECIPITATION MOVES THIS MORNING. IF
IT DOES PRECIPITATE...SOME COOLING FROM THE DRIER AIR WILL ENHANCE
THE FREEZING RAIN THREAT ON UNTREATED ROADS/BRIDGES.
TEMPERATURES SHOULD WARM ABOVE FREEZING THROUGH NOON MOST AREAS
ENDING THE FREEZING RAIN THREAT. THIS SYSTEM EXITS TO THE EAST BY
THIS EVENING WITH CLOUDS REMAINING THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 421 AM CST FRI JAN 23 2015
THE LONG TERM BEGINS SATURDAY TRANQUIL AROUND HERE...BUT A STRONG
NOR EASTER WILL BE PUSHING UP THE EAST COAST WHILE A RIDGE BUILDS
UP THE WEST COAST. BOTH WILL IMPACT THE CLIPPER SET TO DIVE INTO
THE UPPER MIDWEST SATURDAY NIGHT. MODELS HAVE TRENDED SHARPER WITH
THE WAVE WHICH RESULTS IN A WESTWARD SHIFT SIMILAR TO WHAT WAS
SEEN WEDNESDAY NIGHT. GIVEN THE SYNOPTIC SET UP...THIS IS THE
PREFERRED TREND. 00Z NAM WAS FLATTEST AND MUCH FURTHER EAST THAN
THE REST OF THE GUIDANCE AND WAS IGNORED. THE GFS/CANADIAN SEEM
LIKE THE BEST COMPROMISE WITH THE ECMWF A BIT TOO FAST AND
CONSIDERABLY LIGHTER WITH ITS PRECIP. 06Z NAM HAS TRENDED FURTHER
WEST CLOSER TO THE 00Z GFS AND CANADIAN. AT THIS STAGE...IT IS
UNLIKELY THE TRACK WILL SHIFT SIGNIFICANTLY EAST...BUT IT COULD
STILL TREND SLIGHTLY WEST.
THE TRACK OF THE LOW WILL PLAY A SIGNIFICANT ROLE IN WHO SEES THE
MOST ACCUMULATION. A GOOD BAND OF SNOW WILL SET UP ALONG AND JUST
EAST OF THE LOW...WITH SOME POTENTIAL FOR DRY SLOTTING ON THE WEST
SIDE. IT WILL BE A QUICK MOVER...SO ONLY EXPECTING ABOUT 6-9 HOURS
OF ACCUMULATING SNOWFALL. A GENERAL 2-4 INCHES APPEAR LIKELY
WITHIN THE HEART OF THE BAND WITH AMOUNTS GRADUALLY TAPERING OFF
TO THE EAST AND QUICKLY TAPERING OFF TO THE WEST. CURRENTLY...THE
HEAVIEST AXIS OF SNOW IS FORECAST TO SET UP FROM NORTHWEST MN TO
EAST CENTRAL MN AND SOUTHWEST WI. FLURRIES MAY PERSIST INTO
SUNDAY MORNING BUT A SURFACE RIDGE AXIS WILL BUILD IN SUNDAY
AFTERNOON.
ANOTHER CLIPPER WILL BRING A BAND OF LIGHT SNOW ACROSS MN SUNDAY
NIGHT AND INTO WISCONSIN BY MONDAY. THIS WILL BE A SLOWER MOVER
SINCE THE FIRST CLIPPER WILL BE DEVELOPING OFF THE EAST COAST. A
PROLONGED PERIOD OF LIGHT SNOW OR FLURRIES COULD DEVELOP OVER THE
EASTERN AREAS DURING THIS TIME. ACCUMULATIONS WILL BE LIGHTER THAN
WITH THE FIRST SYSTEM.
A PATTERN SHIFT WILL TAKE PLACE TUESDAY AND WEDNESDAY WITH THE
RIDGE BUCKLING TO THE NORTHEAST. A SHOT OF WARMTH WILL SURGE INTO
THE UPPER MIDWEST THANKS TO A 50+ KT 850 MB JET BRINGING +10 TO
+13C AIR IN. GUIDANCE IS WAY TOO COLD IN SUCH A PATTERN...AND
NUDGED TEMPS UP SEVERAL DEGREES. MAY CRACK 50+ ACROSS WRN MN AND
MID TO POSSIBLY UPPER 40S FURTHER EAST.
COLD FRONT WILL DROP SOUTH FOR LATE WEEK AS THE PATTERN SHIFTS
TOWARD SOMETHING MORE COMMON DURING THE LAST YEAR. LUCKILY FOR
US...THE COLDEST SURGE OF ARCTIC AIR WILL ROTATE EAST INTO NEW
ENGLAND AND GIVE US A GLANCING BLOW. EVEN WITH THIS...TEMPS WILL
STILL REMAIN NEAR AVERAGE THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1147 AM CST FRI JAN 23 2015
QUIET STARTING OUT THIS AFTERNOON WITH WIDESPREAD VFR CONDITIONS.
TROUGH AXIS ORIENTED SW TO NE THROUGH CENTRAL MN AT THIS TIME WILL
CONTINUE PUSHING SE THROUGH THE DAY. A SIMILARLY ORIENTED BAND OF
MID CLOUDS CONTINUES PUSHING SOUTHEAST AHEAD OF THE TROUGH AXIS.
LIGHT FREEZING RAIN HAD FALLEN OUT OF THESE CLOUDS THIS
MORNING...BUT LOW LEVEL DRYING CONTINUES PREVENTING MUCH OF
ANYTHING FROM REACHING THE GROUND. MOST OF THE CWA WILL SEE CLEAR
SKIES FOR MUCH OF THE AFTERNOON...BEFORE A SOLID DECK OF STRATUS
CURRENTLY IN NORTHERN MN MOVES INTO CENTRAL MN BY LATE AFTERNOON
AND PROGRESSES TOWARD THE IOWA BORDER THROUGH THE EVENING. LIGHTER
WINDS AND A MELTING SNOW PACK SUGGEST THE DECK EXPANDING AND
LOWERING OVERNIGHT...WITH SOME FOG A POSSIBILITY.
KMSP...LOW LEVEL DRYING HAS MADE FOR A MORE OPTIMISTIC FORECAST
THIS AFTERNOON...WITH CLEAR SKIES HOLDING TRUE UNTIL THE STRATUS
ABRUPTLY ARRIVES AROUND 5-6PM. CIGS WILL NOT GRADUALLY GO
DOWN...BUT INSTEAD WE`LL HAVE CLEAR SKIES SUDDENLY BECOME OVERCAST
WHEN THE STRATUS DECK ARRIVES.
/OUTLOOK FOR KMSP/
SATURDAY NIGHT...BECOMING MVFR. CHC IFR CIGS/VSBYS -SN MAINLY
AFTER 06Z SUN. 1-3" OF ACCUMULATION POSSIBLE. WIND W 5-10 KTS.
SUNDAY...MVFR WITH -SN/IFR POSSIBLE. WIND NW 10G20 KTS.
MONDAY...VFR. WIND SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ044-045-052-
053.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023-
025-027.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
542 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST FRI JAN 23 2015
SHORT TERM CONCERN REMAINS THE THREAT OF FREEZING RAIN/SLEET MOVING
ACROSS THE NORTHERN AND EASTERN CWA MAINLY THROUGH THIS MORNING.
CURRENT RADAR TRENDS INDICATE MODELS MAY BE DOWNPLAYING EXTENT OF
FREEZING RAIN THREAT. WILL FOLLOW A COMBO RAP ISENTROPIC
ANALYSIS (290K/295K LAYERS) AND HRRR TREND FOR POPS THIS AM.
STILL LOOKS THE BEST THREAT REMAINS ALONG AND NORTH OF THE I94
CORRIDOR. WILL LET THE ADV EXPIRE TO THE FAR WEST THROUGH 15Z AND
IN THE EAST BY 18Z. ROAD TEMPERATURE ARE CURRENTLY AROUND 30F IN
THE NORTHERN CWA AND COOLER INTO THE SOUTHERN PORTION OF THE AREA.
SURFACE DEWPTS ARE IN THE LOWER 20S TO THE SOUTH WILL BOTH HELP
AND HINDER FREEZING RAIN THREAT. MAY TAKE SOME TIME TO SATURATE
THE FARTHER SOUTH THE AREA OF PRECIPITATION MOVES THIS MORNING. IF
IT DOES PRECIPITATE...SOME COOLING FROM THE DRIER AIR WILL ENHANCE
THE FREEZING RAIN THREAT ON UNTREATED ROADS/BRIDGES.
TEMPERATURES SHOULD WARM ABOVE FREEZING THROUGH NOON MOST AREAS
ENDING THE FREEZING RAIN THREAT. THIS SYSTEM EXITS TO THE EAST BY
THIS EVENING WITH CLOUDS REMAINING THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 421 AM CST FRI JAN 23 2015
THE LONG TERM BEGINS SATURDAY TRANQUIL AROUND HERE...BUT A STRONG
NOR EASTER WILL BE PUSHING UP THE EAST COAST WHILE A RIDGE BUILDS
UP THE WEST COAST. BOTH WILL IMPACT THE CLIPPER SET TO DIVE INTO
THE UPPER MIDWEST SATURDAY NIGHT. MODELS HAVE TRENDED SHARPER WITH
THE WAVE WHICH RESULTS IN A WESTWARD SHIFT SIMILAR TO WHAT WAS
SEEN WEDNESDAY NIGHT. GIVEN THE SYNOPTIC SET UP...THIS IS THE
PREFERRED TREND. 00Z NAM WAS FLATTEST AND MUCH FURTHER EAST THAN
THE REST OF THE GUIDANCE AND WAS IGNORED. THE GFS/CANADIAN SEEM
LIKE THE BEST COMPROMISE WITH THE ECMWF A BIT TOO FAST AND
CONSIDERABLY LIGHTER WITH ITS PRECIP. 06Z NAM HAS TRENDED FURTHER
WEST CLOSER TO THE 00Z GFS AND CANADIAN. AT THIS STAGE...IT IS
UNLIKELY THE TRACK WILL SHIFT SIGNIFICANTLY EAST...BUT IT COULD
STILL TREND SLIGHTLY WEST.
THE TRACK OF THE LOW WILL PLAY A SIGNIFICANT ROLE IN WHO SEES THE
MOST ACCUMULATION. A GOOD BAND OF SNOW WILL SET UP ALONG AND JUST
EAST OF THE LOW...WITH SOME POTENTIAL FOR DRY SLOTTING ON THE WEST
SIDE. IT WILL BE A QUICK MOVER...SO ONLY EXPECTING ABOUT 6-9 HOURS
OF ACCUMULATING SNOWFALL. A GENERAL 2-4 INCHES APPEAR LIKELY
WITHIN THE HEART OF THE BAND WITH AMOUNTS GRADUALLY TAPERING OFF
TO THE EAST AND QUICKLY TAPERING OFF TO THE WEST. CURRENTLY...THE
HEAVIEST AXIS OF SNOW IS FORECAST TO SET UP FROM NORTHWEST MN TO
EAST CENTRAL MN AND SOUTHWEST WI. FLURRIES MAY PERSIST INTO
SUNDAY MORNING BUT A SURFACE RIDGE AXIS WILL BUILD IN SUNDAY
AFTERNOON.
ANOTHER CLIPPER WILL BRING A BAND OF LIGHT SNOW ACROSS MN SUNDAY
NIGHT AND INTO WISCONSIN BY MONDAY. THIS WILL BE A SLOWER MOVER
SINCE THE FIRST CLIPPER WILL BE DEVELOPING OFF THE EAST COAST. A
PROLONGED PERIOD OF LIGHT SNOW OR FLURRIES COULD DEVELOP OVER THE
EASTERN AREAS DURING THIS TIME. ACCUMULATIONS WILL BE LIGHTER THAN
WITH THE FIRST SYSTEM.
A PATTERN SHIFT WILL TAKE PLACE TUESDAY AND WEDNESDAY WITH THE
RIDGE BUCKLING TO THE NORTHEAST. A SHOT OF WARMTH WILL SURGE INTO
THE UPPER MIDWEST THANKS TO A 50+ KT 850 MB JET BRINGING +10 TO
+13C AIR IN. GUIDANCE IS WAY TOO COLD IN SUCH A PATTERN...AND
NUDGED TEMPS UP SEVERAL DEGREES. MAY CRACK 50+ ACROSS WRN MN AND
MID TO POSSIBLY UPPER 40S FURTHER EAST.
COLD FRONT WILL DROP SOUTH FOR LATE WEEK AS THE PATTERN SHIFTS
TOWARD SOMETHING MORE COMMON DURING THE LAST YEAR. LUCKILY FOR
US...THE COLDEST SURGE OF ARCTIC AIR WILL ROTATE EAST INTO NEW
ENGLAND AND GIVE US A GLANCING BLOW. EVEN WITH THIS...TEMPS WILL
STILL REMAIN NEAR AVERAGE THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 527 AM CST FRI JAN 23 2015
CURRENT RADAR AND MODEL TRENDS CONTINUE TO DROP BAND OF LIGHT
FREEZING RAIN AND SOME SLEET SOUTHEAST OVER THE NORTHEAST CWA
THROUGH 18Z. BEST CHANCES OF THIS OCCURRING AT KSTC-KRNH AND KEAU
THROUGH 18Z. KMSP WILL BE ON THE EDGE OF THE ACTIVITY...BUT STILL
THREAT REMAINS IN THE 14Z-17Z PERIOD. AREA DROPS SOUTHEAST AND
EXITS BY THE AFTERNOON.
NEXT PROBLEM IS THE MVFR CIG THREAT DEVELOPING LATER THIS
AFTERNOON AND TONIGHT. FOLLOWED A SLOWER SREF PROGRESSION FOR
THIS. SHALLOW RH LAYER ON BUFKIT PROFILES SO THERE IS A CHANCE OF
JUST SCT LOWER CLOUDS INTO THE EVENING. WILL HAVE TO MONITOR CLOUD
TRENDS AS ANY REAL LOW CLOUDS RESIDE ALONG THE MN/CANADIAN BORDER.
HIGHER CONFIDENCE IN LOW END MVFR CIGS DEVELOPING INTO THE
EVENING. SURFACE WINDS SOUTHWEST BECOMING MORE WEST/NORTHWEST WITH
PASSAGE OF SURFACE TROUGH TODAY.
KMSP...
STILL OUR CONFIDENCE IS NOT 100% FOR FREEZING RAIN OR SLEET
OCCURRING AT THE AIRPORT. WE CONTINUE TO THINK THE CHANCE IS HIGH
ENOUGH TO INCLUDE THE FREEZING PRECIP IN THE TAF. ANY PRECIP THAT
DOES OCCUR WILL BE LIGHT AND MAY NOT MEASURE. RUNWAY TEMPERATURES
REMAIN 28-30 WITH AIR TEMPERATURE AROUND 30. SOME SLIGHT UPWARD
TREND IN THESE READING SWILL OCCUR THIS MORNING. BUT WILL BE
CRITICAL WHEN GREATEST PSPN THREAT OCCURS...WHICH REMAINS
14Z-17Z FOR KMSP. CONTINUE TO EXPECT MVFR CIGS DEVELOPING LATER
THIS AFTERNOON BEHIND THE TROUGH PASSAGE. THESE LOWER END MVFR
CIGS SHOULD CONTINUE THROUGH THE NIGHT INTO SATURDAY.
/OUTLOOK FOR KMSP/
SATURDAY NIGHT...BECOMING MVFR. CHC IFR CIGS/VSBYS -SN MAINLY
AFTER 06Z SUN. WIND W 5-10 KTS.
SUNDAY...MVFR WITH -SN/IFR POSSIBLE. WIND NW 10G20 KTS.
MONDAY...VFR. WIND SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ043>045-
049>053-061-063.
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ041-
042-048.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023-
025-027.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
421 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST FRI JAN 23 2015
SHORT TERM CONCERN REMAINS THE THREAT OF FREEZING RAIN/SLEET MOVING
ACROSS THE NORTHERN AND EASTERN CWA MAINLY THROUGH THIS MORNING.
CURRENT RADAR TRENDS INDICATE MODELS MAY BE DOWNPLAYING EXTENT OF
FREEZING RAIN THREAT. WILL FOLLOW A COMBO RAP ISENTROPIC
ANALYSIS (290K/295K LAYERS) AND HRRR TREND FOR POPS THIS AM.
STILL LOOKS THE BEST THREAT REMAINS ALONG AND NORTH OF THE I94
CORRIDOR. WILL LET THE ADV EXPIRE TO THE FAR WEST THROUGH 15Z AND
IN THE EAST BY 18Z. ROAD TEMPERATURE ARE CURRENTLY AROUND 30F IN
THE NORTHERN CWA AND COOLER INTO THE SOUTHERN PORTION OF THE AREA.
SURFACE DEWPTS ARE IN THE LOWER 20S TO THE SOUTH WILL BOTH HELP
AND HINDER FREEZING RAIN THREAT. MAY TAKE SOME TIME TO SATURATE
THE FARTHER SOUTH THE AREA OF PRECIPITATION MOVES THIS MORNING. IF
IT DOES PRECIPITATE...SOME COOLING FROM THE DRIER AIR WILL ENHANCE
THE FREEZING RAIN THREAT ON UNTREATED ROADS/BRIDGES.
TEMPERATURES SHOULD WARM ABOVE FREEZING THROUGH NOON MOST AREAS
ENDING THE FREEZING RAIN THREAT. THIS SYSTEM EXITS TO THE EAST BY
THIS EVENING WITH CLOUDS REMAINING THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 421 AM CST FRI JAN 23 2015
THE LONG TERM BEGINS SATURDAY TRANQUIL AROUND HERE...BUT A STRONG
NOR EASTER WILL BE PUSHING UP THE EAST COAST WHILE A RIDGE BUILDS
UP THE WEST COAST. BOTH WILL IMPACT THE CLIPPER SET TO DIVE INTO
THE UPPER MIDWEST SATURDAY NIGHT. MODELS HAVE TRENDED SHARPER WITH
THE WAVE WHICH RESULTS IN A WESTWARD SHIFT SIMILAR TO WHAT WAS
SEEN WEDNESDAY NIGHT. GIVEN THE SYNOPTIC SET UP...THIS IS THE
PREFERRED TREND. 00Z NAM WAS FLATTEST AND MUCH FURTHER EAST THAN
THE REST OF THE GUIDANCE AND WAS IGNORED. THE GFS/CANADIAN SEEM
LIKE THE BEST COMPROMISE WITH THE ECMWF A BIT TOO FAST AND
CONSIDERABLY LIGHTER WITH ITS PRECIP. 06Z NAM HAS TRENDED FURTHER
WEST CLOSER TO THE 00Z GFS AND CANADIAN. AT THIS STAGE...IT IS
UNLIKELY THE TRACK WILL SHIFT SIGNIFICANTLY EAST...BUT IT COULD
STILL TREND SLIGHTLY WEST.
THE TRACK OF THE LOW WILL PLAY A SIGNIFICANT ROLE IN WHO SEES THE
MOST ACCUMULATION. A GOOD BAND OF SNOW WILL SET UP ALONG AND JUST
EAST OF THE LOW...WITH SOME POTENTIAL FOR DRY SLOTTING ON THE WEST
SIDE. IT WILL BE A QUICK MOVER...SO ONLY EXPECTING ABOUT 6-9 HOURS
OF ACCUMULATING SNOWFALL. A GENERAL 2-4 INCHES APPEAR LIKELY
WITHIN THE HEART OF THE BAND WITH AMOUNTS GRADUALLY TAPERING OFF
TO THE EAST AND QUICKLY TAPERING OFF TO THE WEST. CURRENTLY...THE
HEAVIEST AXIS OF SNOW IS FORECAST TO SET UP FROM NORTHWEST MN TO
EAST CENTRAL MN AND SOUTHWEST WI. FLURRIES MAY PERSIST INTO
SUNDAY MORNING BUT A SURFACE RIDGE AXIS WILL BUILD IN SUNDAY
AFTERNOON.
ANOTHER CLIPPER WILL BRING A BAND OF LIGHT SNOW ACROSS MN SUNDAY
NIGHT AND INTO WISCONSIN BY MONDAY. THIS WILL BE A SLOWER MOVER
SINCE THE FIRST CLIPPER WILL BE DEVELOPING OFF THE EAST COAST. A
PROLONGED PERIOD OF LIGHT SNOW OR FLURRIES COULD DEVELOP OVER THE
EASTERN AREAS DURING THIS TIME. ACCUMULATIONS WILL BE LIGHTER THAN
WITH THE FIRST SYSTEM.
A PATTERN SHIFT WILL TAKE PLACE TUESDAY AND WEDNESDAY WITH THE
RIDGE BUCKLING TO THE NORTHEAST. A SHOT OF WARMTH WILL SURGE INTO
THE UPPER MIDWEST THANKS TO A 50+ KT 850 MB JET BRINGING +10 TO
+13C AIR IN. GUIDANCE IS WAY TOO COLD IN SUCH A PATTERN...AND
NUDGED TEMPS UP SEVERAL DEGREES. MAY CRACK 50+ ACROSS WRN MN AND
MID TO POSSIBLY UPPER 40S FURTHER EAST.
COLD FRONT WILL DROP SOUTH FOR LATE WEEK AS THE PATTERN SHIFTS
TOWARD SOMETHING MORE COMMON DURING THE LAST YEAR. LUCKILY FOR
US...THE COLDEST SURGE OF ARCTIC AIR WILL ROTATE EAST INTO NEW
ENGLAND AND GIVE US A GLANCING BLOW. EVEN WITH THIS...TEMPS WILL
STILL REMAIN NEAR AVERAGE THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1142 PM CST THU JAN 22 2015
VFR TONIGHT...WITH A BAND OF LIGHT FREEZING RAIN OR SLEET COMING
THROUGH BETWEEN 12-18Z THIS MORNING...FOLLOWED BY MVFR CEILINGS IN
THE AFTERNOON AND EVENING. THE PRECIP SHOULD BE LIGHT AND AFFECT
AREAS PRIMARILY NEAR AND NORTH OF THE I-94 CORRIDOR.
UNFORTUNATELY...THAT MEANS MOST TAF SITES /BESIDES KAXN AND KRWF/
HAVE A 1-2 HOUR WINDOW WHERE LIGHT SLEET OR LIGHT FREEZING RAIN IS
POSSIBLE. TEMPS ARE EXPECTED TO GET ABOVE FREEZING BY THE LATE
MORNING AND EARLY AFTERNOON. SO...ANY SLICK SPOTS ON RUNWAYS
SHOULD MELT THIS AFTERNOON. THE MVFR CEILINGS SHOULD ARRIVE BEHIND
THE PRECIP FOR THE 2ND HALF OF THE TAF PERIOD.
KMSP...
WE`RE NOT 100% CONFIDENT IN FREEZING RAIN OR SLEET AT THE
AIRPORT...BUT IF IT MISSES KMSP...IT WILL NOT BE BY MUCH. WE THINK
THE CHANCE IS HIGH ENOUGH TO INCLUDE THE FREEZING PRECIP IN THE
TAF AT THIS POINT. THIS PRECIP...HOWEVER...SHOULD COME AFTER THE
HIGHER TRAFFIC THIS MORNING. THERE WILL DEFINITELY BE MORE STUFF
SHOWING UP ON RADAR TO THE NORTH AND EAST OF THE AIRPORT. KMSP
WILL BE ON THE SOUTHERN END OF THE PRECIP.
/OUTLOOK FOR KMSP/
SATURDAY...VFR. WIND W 5-10 KTS.
SUNDAY...MVFR WITH -SN/IFR POSSIBLE. WIND NW 10G20 KTS.
MONDAY...VFR. WIND SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ043>045-
049>053-061-063.
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ041-
042-048.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023-
025-027.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS JACKSON MS
1040 AM CST FRI JAN 23 2015
.UPDATE...SURFACE ANALYSIS HAD THE LOW JUST SOUTH OF THE FLORIDA
PANHANDLE. THE BACK EDGE OF THE MAIN RAIN SHIELD HAS SHIFTED
SOUTHEAST OF OUR CWA AND WL CONTINUE TO SHIFT FARTHER EAST AS THE
SURFACE LOW LIFTS NORTHEAST THIS AFTERNOON. HOWEVER...LIGHT RAIN AND
LIGHT DRIZZLE WILL CONTINUE OVER OUR CWA AHEAD OF AN APPROACHING
UPPER LEVEL TROUGH THAT WAS NOTED OVER THE SOUTHERN PLAINS THIS
MORNING. WITH THE GUSTY NORTH WIND BENEATH OVERCAST SKIES AND LIGHT
PRECIPITATION THIS AFTERNOON...TEMPERATURES WILL STRUGGLE TO WARM
AND REMAIN NEARLY STATIONARY UNTIL THIS EVENING. TEMPERATURES WILL
RUN IN THE UPPER 30S TO LOWER 40S AT MOST LOCATIONS. POPS ACROSS THE
SOUTHEAST WERE LOWERED WITH THE UPDATE BUT TEMPERATURES WERE ON
TRACK. /22/
&&
.AVIATION...IFR CONDITIONS WILL PREVAIL THROUGH MUCH OF THE DAY WITH
CONTINUED -RA DURING THE DAYTIME HOURS. CEILINGS/VISBYS WILL BEGIN
TO IMPROVE IN THE NORTH TONIGHT...REACHING VFR AT SITES LIKE GLH AND
GWO BY AROUND OR SHORTLY AFTER MIDNIGHT. FARTHER SOUTH CONDITIONS
WILL BE SLOWER TO IMPROVE...REACHING MVFR BY DAYBREAK. HOWEVER MVFR
CEILINGS MAY PERSIST INTO THE MORNING SATURDAY. PRECIP WILL END FROM
WEST TO EAST AROUND MIDNIGHT TONIGHT. PRECIP MAY MIX WITH OR CHANGE
OVER TO -SN AFTER 00Z MAINLY AT NORTHERN TAF SITES...GLH GWO AND
GTR...HOWEVER NO NOTABLE ISSUES ARE EXPECTED AT THE SURFACE. /DL/
&&
.PREV DISCUSSION... /ISSUED 328 AM CST FRI JAN 23 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...STRONG DEEP LAYERED
WARM ADVECTION HAS BEEN RESPONSIBLE OVERNIGHT FOR THE WIDESPREAD
MODERATE TO AT TIMES HEAVY RAIN OVER THE CWA. CURRENT RADAR TRENDS
AND MODEL DATA IN AGREEMENT THAT THE DEEP LAYERED ASCENT WILL SHIFT
EAST TODAY LEAVING BEHIND A RAW...CLOUDY...DRIZZLY DAY FOR THE CWA.
EVEN THOUGH THE AREA IS BEING DRY SLOTTED IN ADVANCE OF THE MID/UPPER
LEVEL COLD CORE...BELIEVE BOUNDARY LAYER COOLING WILL MAINTAIN CLOUD
COVER AND PERIODS OF LIGHT RAIN/DRIZZLE. HRRR OUTPUT IS SHOWING THE
MAJORITY OF THE PRECIP CLEAR OUT OVER THE SE TWO THIRDS...BUT
MAINTAINS A NEAR STEADY BAND OF LIGHT RAIN OVER NW SECTIONS IN CLOSE
PROXIMITY TO THE DEFORMATION ZONE.
AS THE MID/UPPER LEVEL COLD CORE MOVES THROUGH TONIGHT...DEEP
LAYERED COOLING WILL ALLOW FOR RISING THETA SURFACE AND MORE LIGHT
PRECIPITATION. BUFR SOUNDINGS CONTINUE TO SHOW SOME POSSIBILITY OF
LIGHT SNOW MIXING IN WITH THE LIGHT RAIN ALONG THE HIGHWAY 82
CORRIDOR BEFORE ALL THE PRECIPITATION COMES TO AN END AFTER MIDNIGHT.
CLOUDS CLEARING OUT DURING THE MORNING SATURDAY WILL GIVE WAY TO
SUNNY SKIES BY AFTERNOON. MAX TEMPS SHOULD BE MAKE IT INTO THE LOW TO
MID 50S./26/
LONG TERM...SUNDAY THROUGH NEXT WORK WEEK...PRONOUNCED NORTHWEST
FLOW ALOFT WILL EXIST OVER THE REGION SUNDAY THROUGH WEDNESDAY OF
NEXT WEEK...UPSTREAM OF A LONGWAVE TROUGH CENTERED NEAR THE EAST
COAST. THIS PATTERN WILL PROMOTE A FEW CONTINENTAL COLD AIR SURGES
MAINLY EAST OF THE MS RIVER THROUGH THIS TIME...WITH ANY REAL
CHANCES OF PRECIP ASSOCIATED WITH THESE SURGES (AND MOST OF THE
CLOUDS) CONFINED WELL TO OUR NORTH AND EAST. THE GENERAL PATTERN
SUGGESTS 3 TO 4 DAYS OF EFFICIENT DAYTIME MIXING (AND THEREFORE
WARMING) WITH NIGHTS CAPABLE OF GOOD RADIATIONAL COOLING. BLENDED
GUIDANCE TEMPERATURES WERE MAINLY ON THE WARM SIDE OF AVERAGE
(ESPECIALLY ACROSS SOUTHWESTERN ZONES) AND DEVIATIONS FROM THE MAIN
BLEND WERE NOT MAJOR. HOWEVER...I DID TEND TO FOLLOW LATEST
OPERATIONAL EURO IDEA OF TIMING OF COOL AIR SURGES SUNDAY NIGHT AND
AGAIN AROUND TUESDAY NIGHT...AND SUBTLY TRENDING GUIDANCE COOLER (OR
WARMER) BASED ON THE UNDETAILED BLEND. ALL IN ALL...THIS SHOULD BE
DECENT PERIOD OF WEATHER FOR THE REGION CONSIDERING THE CALENDAR
DATE.
BY LATE IN THE WORK WEEK SOUTHERN STREAM ENERGY WILL START MAKING
INROADS TOWARD THE REGION...INCREASING CLOUDS AND GRADUALLY
INCREASING RAIN CHANCES. THE TYPICALLY-SOLID EUROPEAN OPERATIONAL
MODEL STILL IS INSISTENT ON CUTTING OFF A BIG PIECE OF THIS SOUTHERN
STREAM ENERGY NEAR BAJA CALIFORNIA...WHICH WOULD HAVE THE EFFECT OF
CONFINING INCLEMENT WEATHER MOSTLY WEST OF OUR REGION.
HOWEVER...CONSENSUS OF OTHER LONG RANGE MODELS TENDS TO PHASE THIS
ENERGY WITH THIS NORTHERN STREAM...WHICH WOULD ENSURE MUCH MORE
IMPACT IN OUR REGION. THE LATTER CONSENSUS ALSO TENDS TO SUGGESTS
ARRIVAL OF PRECIP COULD COINCIDE WITH A LARGER COLD AIR SURGE INTO
THE SOUTH...AND THAT IS OF COURSE AN INTERESTING PROSPECT. BUT ANY
MEANINGFUL JUXTAPOSITION OF THOSE TWO ELEMENTS WOULD BE BEYOND THE
CURRENT LONG TERM PERIOD SO WE HAVE SOME MORE TIME TO LET MODEL
INCONGRUITIES LESSEN. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 43 34 53 34 / 53 73 8 2
MERIDIAN 46 35 52 31 / 54 70 10 3
VICKSBURG 42 33 54 36 / 73 66 6 2
HATTIESBURG 48 36 55 34 / 54 51 8 2
NATCHEZ 43 34 55 36 / 68 56 7 2
GREENVILLE 41 32 53 35 / 89 51 6 2
GREENWOOD 41 31 53 34 / 81 65 7 2
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
22/DL/26/BB
AREA FORECAST DISCUSSION
NWS JACKSON MS
328 AM CST FRI JAN 23 2015
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...STRONG DEEP LAYERED
WARM ADVECTION HAS BEEN RESPONSIBLE OVERNIGHT FOR THE WIDESPREAD
MODERATE TO AT TIMES HEAVY RAIN OVER THE CWA. CURRENT RADAR TRENDS
AND MODEL DATA IN AGREEMENT THAT THE DEEP LAYERED ASCENT WILL SHIFT
EAST TODAY LEAVING BEHIND A RAW...CLOUDY...DRIZZLY DAY FOR THE CWA.
EVEN THOUGH THE AREA IS BEING DRY SLOTTED IN ADVANCE OF THE MID/UPPER
LEVEL COLD CORE...BELIEVE BOUNDARY LAYER COOLING WILL MAINTAIN CLOUD
COVER AND PERIODS OF LIGHT RAIN/DRIZZLE. HRRR OUTPUT IS SHOWING THE
MAJORITY OF THE PRECIP CLEAR OUT OVER THE SE TWO THIRDS...BUT
MAINTAINS A NEAR STEADY BAND OF LIGHT RAIN OVER NW SECTIONS IN CLOSE
PROXIMITY TO THE DEFORMATION ZONE.
AS THE MID/UPPER LEVEL COLD CORE MOVES THROUGH TONIGHT...DEEP
LAYERED COOLING WILL ALLOW FOR RISING THETA SURFACE AND MORE LIGHT
PRECIPITATION. BUFR SOUNDINGS CONTINUE TO SHOW SOME POSSIBILITY OF
LIGHT SNOW MIXING IN WITH THE LIGHT RAIN ALONG THE HIGHWAY 82
CORRIDOR BEFORE ALL THE PRECIPITATION COMES TO AN END AFTER MIDNIGHT.
CLOUDS CLEEARING OUT DURING THE MORNING SATURDAY WILL GIVE WAY TO
SUNNY SKIES BY AFTERNOON. MAX TEMPS SHOULD BE MAKE IT INTO THE LOW TO
MID 50S./26/
.LONG TERM...SUNDAY THROUGH NEXT WORK WEEK...PRONOUNCED NORTHWEST
FLOW ALOFT WILL EXIST OVER THE REGION SUNDAY THROUGH WEDNESDAY OF
NEXT WEEK...UPSTREAM OF A LONGWAVE TROUGH CENTERED NEAR THE EAST
COAST. THIS PATTERN WILL PROMOTE A FEW CONTINENTAL COLD AIR SURGES
MAINLY EAST OF THE MS RIVER THROUGH THIS TIME...WITH ANY REAL
CHANCES OF PRECIP ASSOCIATED WITH THESE SURGES (AND MOST OF THE
CLOUDS) CONFINED WELL TO OUR NORTH AND EAST. THE GENERAL PATTERN
SUGGESTS 3 TO 4 DAYS OF EFFICIENT DAYTIME MIXING (AND THEREFORE
WARMING) WITH NIGHTS CAPABLE OF GOOD RADIATIONAL COOLING. BLENDED
GUIDANCE TEMPERATURES WERE MAINLY ON THE WARM SIDE OF AVERAGE
(ESPECIALLY ACROSS SOUTHWESTERN ZONES) AND DEVIATIONS FROM THE MAIN
BLEND WERE NOT MAJOR. HOWEVER...I DID TEND TO FOLLOW LATEST
OPERATIONAL EURO IDEA OF TIMING OF COOL AIR SURGES SUNDAY NIGHT AND
AGAIN AROUND TUESDAY NIGHT...AND SUBTLY TRENDING GUIDANCE COOLER (OR
WARMER) BASED ON THE UNDETAILED BLEND. ALL IN ALL...THIS SHOULD BE
DECENT PERIOD OF WEATHER FOR THE REGION CONSIDERING THE CALENDAR
DATE.
BY LATE IN THE WORK WEEK SOUTHERN STREAM ENERGY WILL START MAKING
INROADS TOWARD THE REGION...INCREASING CLOUDS AND GRADUALLY
INCREASING RAIN CHANCES. THE TYPICALLY-SOLID EUROPEAN OPERATIONAL
MODEL STILL IS INSISTENT ON CUTTING OFF A BIG PIECE OF THIS SOUTHERN
STREAM ENERGY NEAR BAJA CALIFORNIA...WHICH WOULD HAVE THE EFFECT OF
CONFINING INCLEMENT WEATHER MOSTLY WEST OF OUR REGION.
HOWEVER...CONSENSUS OF OTHER LONG RANGE MODELS TENDS TO PHASE THIS
ENERGY WITH THIS NORTHERN STREAM...WHICH WOULD ENSURE MUCH MORE
IMPACT IN OUR REGION. THE LATTER CONSENSUS ALSO TENDS TO SUGGESTS
ARRIVAL OF PRECIP COULD COINCIDE WITH A LARGER COLD AIR SURGE INTO
THE SOUTH...AND THAT IS OF COURSE AN INTERESTING PROSPECT. BUT ANY
MEANINGFUL JUXTAPOSITION OF THOSE TWO ELEMENTS WOULD BE BEYOND THE
CURRENT LONG TERM PERIOD SO WE HAVE SOME MORE TIME TO LET MODEL
INCONGRUITIES LESSEN. /BB/
&&
.AVIATION...IFR CIGS AND MVFR VSBYS WILL BE THE RULE THROUGH THE
PERIOD AS AREAS OF LIGHT RAIN AND DRIZZLE CONTINUE OVER THE AREA.
CIGS MAY RISE TO MVFR AFTER 00Z IN THE GLH/GWO AREAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 43 34 53 34 / 55 73 8 2
MERIDIAN 46 35 52 31 / 78 70 10 3
VICKSBURG 42 33 54 36 / 75 66 6 2
HATTIESBURG 48 36 55 34 / 63 51 8 2
NATCHEZ 43 34 55 36 / 69 56 7 2
GREENVILLE 42 32 53 35 / 94 51 6 2
GREENWOOD 41 31 53 34 / 82 65 7 2
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
909 PM CST Sat Jan 24 2015
.UPDATE:
Issued at 835 PM CST Sat Jan 24 2015
The radar was showing relatively weak reflectivities across
southwest IA, northeast KS, and into extreme northwest MO this
evening. Some of this light rain was evaporating before making it
to the ground due to an initially dry surface/boundary layer. This
rain was ahead of an approaching shortwave over southeast SD and a
weaker shortwave over eastern KS. This light rain should spread
into portions of northeast and central MO around midnight per the
latest HRRR model run. The latest NAM model run appears a little
deficient in its QPF tonight across MO. The light rain will spread
southeastward into much of the rest of our forecast area late
tonight/early Sunday morning as the main shortwave amplifies into
an upper level low and the surface low now over northwest IA and
southwest MN drops southeastward to just west of UIN by 12z
Sunday. Low temperatures tonight will be well above normal for
late January due to the lowering and thickening cloud cover along
with southwesterly surface winds for much of our area for most of
the remainder of tonight.
GKS
&&
.SHORT TERM: (Through Late Tonight)
Issued at 322 PM CST Sat Jan 24 2015
Elongated shortwave extending from Saskatchewan southeast into
Montana will dive southeast into Missouri by late tonight. The
associated low level circulation will drive southeast across Iowa
tonight and into extreme northeast Missouri by 12Z. All models are
printing out fairly widespread/light QPF ahead of the shortwave
along and north of the I-44 corridor from the Ozarks north to the
I-70 corridor. Another area of light QPF is showing up over
northern Missouri closer to the low level circulation. GFS and NAM
show a pretty broad area of 850-500mb omega ahead of the shortwave,
and a band of 850mb moisture convergence which sweeps through
Missouri into western Illinois ahead of the 850mb cold front. These
features appear to be the primary drivers for precipitation
tonight. 4KM ARW and NMM WRF members develop a broad area of
simulated reflectivity across the aforementioned parts of the CWFA
and MOS PoPs are likely to categorical in these areas as well.
Given all this, have increased PoPs from I-44 north to Quincy to
likely or better late tonight...with much of southwest Illinois east
of the STL Metro still staying in the high chance category. Kept
temperatures pretty mild in the mid 30s to near 40 with clouds and
southwest flow.
Carney
.LONG TERM: (Sunday through Next Saturday)
Issued at 322 PM CST Sat Jan 24 2015
(Sunday-Tuesday)
Over the last few days the synoptic guidance has been trending a bit
stronger/a bit more southwesterly with Sunday`s clipper system.
12z guidance has also followed this trend, with associated MOS also
indicating a sizeable jump in PoPs as well for the day on Sunday.
It would appear that band of rain that develops overnight will sweep
east into southern/eastern sections of the CWA early Sunday, along
and east of system`s cold front and in area of strong UVV with
initial shot of vorticity with upper system. This area of rain
will be followed by additional pockets of precip sprialling around
the upper low as it works into southern Illinois during the day.
While 850mb temps drop fairly quickly (model consensus indicates
0C isotherm will advect into southern sections of the CWA by
18z), forecast sounding from both NAM and GFS indicate cooling of
low level AMS and the drop of the freezing level to support snow
will be much slower than suggested by 850 mb temps alone. This
makes sense given the strong low level warming that should occur
ahead of the clipper later tonight and into early Sunday. Started
a changeover to snow in our far north by mid morning, with the
changeover dipping into the Ozarks in MO and to near the I70
corridor in IL by 00z Monday. Given how warm we are getting today
and the fact that it appears that the precip will be fairly light
once the changeover to snow occurs, it appears that any
accumulations will be quite minor...generally less than one-half
an inch and primarily near/east of the UIN area.
Precip in the form of light rain and light snow will wind down
across southeast sections of the CWA Sunday evening, with the quick
shot of cold air in the wake of the Clipper dropping temps into the
lower to middle 20s.
All of the 12z guidance indicates a very rapid rebound in temps on
Monday as the upper ridge over the Rockies begins to build into the
Plains. 30s will linger over our eastern counties but 40s seem
likely for areas along and west of the Mississippi...with some
locations in mid MO possibly pushing the 50 degree mark.
Shortwave partially driving Monday`s moderation will drop into the
east coast trof Monday night, with the CAA in the wake of the
shortwave allowing a weak cold front to drop into the mid
Mississippi Valley. However, greatest push of cold air will be well
east of our CWA, so Tuesday`s temps should be in the 40s over
most of the FA.
(Wednesday-Saturday)
Unseasonably warm airmass over the Plains should work its way east
at midweek as the UA pattern over the CONUS becomes progressive and
upper ridge works into the mid-Mississippi Valley. Given the
intensity of the warm air have gone a bit above initialization
numbers with a few locastion in mid MO pushing 60.
Next system in the increasingly active flow regime passes through
the area on Wednesday night. Cold air in the wake of the system
should return temps to more normal levels on Thursday, with temps
dropping a few more degrees on Friday.
While medium range solutions are in very good agreement into
Friday, they diverge considerably heading into the end of the
week. Both GFS and ECMWF develop a cut-off low over the southwestern
U.S. but mid level flow over the central CONUS varies considerably,
with GFS indicating a nearly zonal flow regime from the Rockies
into the east coast while the ECMWF suggests trof deepening over
the eastern half of the country...a much colder solution for our
area by next Saturday (ECMWF 850mb temps are about 10 degrees
colder than those of the GFS). For now have leaned towards the
warmer GFS, with a chance of rain or snow as broad overrunning is
progged across the region.
Truett
&&
.AVIATION: (For the 00z TAFs through 00z Sunday Evening)
Issued at 607 PM CST Sat Jan 24 2015
Mid and high clouds moving in ahead of next weather system. Cigs
to lower to low end vfr between 08z-11z Sunday with rain moving
in. Rain will be on the increase with cigs/vsbys lowering to mvfr.
Then as system slides southeast through region will see winds
pickup and veer to the northwest to north gusting to near 25kts at
times. Will see a bit of a break in activity by mid to late
morning for taf sites along I-70, so kept vcsh mention. Then as
colder air filters in rain to become mixed with snow Sunday
afternoon and evening.
Specifics for KSTL:
Mid and high clouds moving in ahead of next weather system. Cigs
to lower to low end vfr by 11z Sunday with rain moving
in. Rain will be on the increase with cigs/vsbys lowering to mvfr.
Then as system slides southeast through region will see winds
pickup and veer to the north gusting to near 25kts at times. Will
see a bit of a break in activity by mid to late morning for taf
sites along I-70, so kept vcsh mention. Then as colder air filters
in rain to become mixed with snow by 21z Sunday.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
831 PM CST Sat Jan 24 2015
.UPDATE...
Issued at 831 AM CST SAT JAN 24 2015
First round of rain is coming in a bit heavier than previously
thought and has been able to penetrate dry air at the surface. Still,
upstream observations indicate only one or two hundredths of an inch
of rain will fall from this activity, if that. Could see light rain
or sprinkles make it as far east as central MO later this evening.
Temperatures further upstream across Nebraska and the Dakotas are
warmer than many models had indicated. Near-term models such as the
RAP and HRRR seem to have a better grasp on this, so these were used
to update temperatures overnight and into Sunday morning which do not
appear as supportive of snow over northern MO. Still could see a few
flakes across these areas especially after 10 AM or so.
&&
.DISCUSSION...
Issued at 252 PM CST SAT JAN 24 2015
Tonight/Sunday...Confidence remains for chances of light
precipitation to overspread portions of the forecast area tonight
through Sunday. As of early this afternoon, water vapor imagery
showed a shortwave trough over eastern Montana into the western
Dakotas. This upper disturbance will rapidly drop southeastward,
reaching our forecast area by sunrise Sunday, and remain the
catalyst for the uptick in active weather during the next 24 hours.
Initial precipitation may develop in advance of strong PVA over east
central Kansas, sliding into west central Missouri before expanding
in coverage to the east. An additional area may also be initially
focused closer to the surface low pressure in northeast Missouri.
The initial coverage of precipitation prior to 09-12Z may be
somewhat spotty, with all precipitation falling in the form of rain,
per forecast soundings showing a notable warm layer several kft
above the surface. As the upper disturbance moves through with the
remaining area of deep ascent, a broader area of light precipitation
is expected to move through the region beginning Sunday morning. The
best chances will be across the northeast half of the CWA, with
decreasing chances with southwest extent. Upon the cold frontal
passage, colder air will advect into the area. Forecast soundings
show a cold/saturated enough profile to support snow or a mix of
rain/snow over portions of northern and northeastern Missouri during
the day on Sunday. Where snow can occur, considering light/meager
snow rates, relatively warm ground temperatures, and 2m air
temperatures above freezing, little to no accumulation is expected,
with any dusting reserved for grassy, insulated-type surfaces. All
precipitation is expected to exit from west to east by sunset Sunday.
The cooler weather on Sunday will be short-lived as the upper
pattern remains highly amplified, with a large ridge over the
Intermountain West Monday into Tuesday. Warm H85 temperatures on the
order of 10-13C will overspread much of the Central Plains Monday
through Wednesday, yielding afternoon high temperatures well above
seasonal levels for the region. The warmest day for the forecast
area should occur on Wednesday ahead of the next cold front as the
upper pattern begins to break down, with highs in the middle 50s to
lower 60s. Otherwise, cooler weather is expected to through the
remainder of the work week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 530 PM CST SAT JAN 24 2015
Many radar returns over KS/NE are not reaching the ground, and light
showers may not make it into the KC area until after sunrise. Even
then, activity should be scattered and light with few impacts to
airport operations. Any precipitation that makes it as far south and
west as KC is expected to be all rain, with perhaps some snow mixed
in further north toward STJ and IRK.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
DISCUSSION...Blair
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
917 AM CST Fri Jan 23 2015
.UPDATE:
Issued at 911 AM CST Fri Jan 23 2015
In the process of updating forecast to reflect a slower clearing
across the CWA. Will be tweaking sky trends to more closely reflect
14z RUC 925MB RH progs...which suggests clouds will still be
holding tough over the eastern half of the CWA at 18z. However,
think that clearing will make it into our eastern counties by late
afternoon as dry air is advected east by increasing westerly low
level winds.
Truett
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 240 AM CST Fri Jan 23 2015
A low pressure system moving through the southern CONUS will have
very little effect on today`s weather except for an increase in high
level clouds across the southern CWA. Highs in the 40s will be above
average for mid to late January.
Kanofsky
.LONG TERM: (Tonight through Thursday)
Issued at 240 AM CST Fri Jan 23 2015
A storm system centered over western TX, yet having influence well
to its east across much of the deep South, is expected to move to
the east over the next 24 hours and not have much of an impact for
our region. As a result, quiet wx is forecast for tonight.
Intermittent periods of clouds and not a particularly strong cold
front later will yield min temps above normal for this time of year,
with mid-upper 20s.
In this storm system`s wake beginning later tonight, we will see a
resumption of the familiar winter pattern of NW flow and this is
expected to last thru Tuesday of next week. There is really only
one system of any note during this period, and that is a strong
clipper system that has been discussed at length for several days
now. This clipper system is still on track to impact our region
primarily on Sunday. Model diffs continue to exist on the track and
structure, with the NAM the biggest outlier, and least reliable on
Day 3. The EC and GFS solutions are greatly preferred here. They
feature an initial strong disturbance that cuts into northwest MO
thru dawn Sunday, with the energy then splitting in two: the
northern portion tracking almost due east to Cincinnati, OH by early
Sunday evening, and the southern portion continuing to dig
southeastward to Memphis, TN. The initial phase thru dawn on Sunday
has a unified broadscale lift to it across the entire region at some
point, but with all of the moisture of any note on the very backside
of the region of lift. What should be anticipated from this is a
brief shot of pcpn for most locations but will struggle to measure.
Have broad-brushed low PoPs for virtually the entire forecast area.
Pcpn-types are expected to be liquid for this with boundary layer
temps too warm, not being helped out at all from SW winds at the
time. By Sunday daytime, the split in the system will result in the
high PoP/accumulating snow region to extend well to our
northeast--from Chicago, IL to northern OH--with once again a
broad-brushed region of low PoPs extending well to the south where
an invigorated broadscale lift region during mainly the morning and
midday hours will largely be cancelled out by moisture loss.
Boundary layer temps will once again preclude snow in the low PoP
region over us, with only spotty light rain expected. The system
should be gone and well east by nightfall Sunday. Prefer GFS QPF
with a hundredth or two only with EC too high on its values.
A weak front late Monday may result in a threat for light pcpn, but
prefer to wait for another model iteration before adding any
mention, otherwise dry until the middle of next week.
Temps will be primarily a tug of war between above normal and a
return to seasonable values with what few cold air intrusions there
will be.
An even milder period looks on tap for Wednesday and Thursday next
week with an upper level ridge building overhead and S-SW flow at
the surface.
TES
&&
.AVIATION: (For the 12z TAFs through 12z Saturday Morning)
Issued at 537 AM CST Fri Jan 23 2015
Specifics for KUIN: MVFR stratus in place should eventually advect
eastward today, leaving VFR conditions for most of the afternoon
and evening. Some lower clouds may accompany a cold front when it
moves through after 24/06z.
Specifics for KCOU: MVFR stratus has locally cleared out near KCOU
however a lingering batch was located upstream. It may produce
MVFR conditions at KCOU at times until it starts to dissipate.
Thereafter, expect a prolonged period of VFR conditions until a
cold front arrives late tonight after 24/09z. Some lower clouds
may accompany the front.
Specifics for KSTL, KCPS, KSUS: Back edge of MVFR stratus has
been making slow progress eastward, but new westward development
over south central MO does raise some doubts about how quickly the
stratus will clear out. Once it does clear out, though, expect
several hours of VFR conditions before low-end VFR or high-end
MVFR cigs arrive with a cold front after 24/10z.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
552 PM CST SAT JAN 24 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 324 PM CST SAT JAN 24 2015
STRONG SHORTWAVE BRINGING COLDER TEMPERATURES AND A CHANCE FOR RAIN
AND SNOW THROUGH SUNDAY...THEN WARMER TEMPERATURES AGAIN TO START
THE WORK WEEK...REMAIN THE PRIMARY FORECAST CHALLENGES.
STRONG SHORTWAVE WAS NOTED ON WATER VAPOR IMAGERY DIVING THROUGH
EASTERN MONTANA THIS AFTERNOON. RAP ANALYSIS SHOWS 150KT 300MB JET
ACCOMPANYING SHORTWAVE. BOTH FEATURES WILL MOVE TOWARD OUR AREA
LATER THIS EVENING AND PROGRESS TO THE EAST ON SUNDAY. SCATTERED
SHOWERS WERE ALREADY OCCURRING IN WESTERN NEBRASKA CAUSED BY WEAK
VORTICITY LOBE AHEAD OF SHORTWAVE...WITH WING OF WARM ADVECTION
RAIN/SNOW EXTENDING FROM NORTH DAKOTA INTO EASTERN SOUTH DAKOTA
AHEAD OF MAIN SHORTWAVE. COULD SEE ISOLATED SHOWERS/SPRINKLES THIS
EVENING WITH WESTERN NEBRASKA ACTIVITY...BUT MAIN PRECIP CHANCE
WILL COME LATER THIS EVENING WITH NORTHERN PLAINS ACTIVITY. EXPECT
RAIN CHANCES TO INCREASE MARKEDLY BY MIDNIGHT ACROSS ALL OF
EASTERN NEBRASKA AND WESTERN IOWA...WITH LIKELY POPS IN OUR NORTH
WHERE LIFT ASSOCIATED BY MID LEVEL WARM ADVECTION IS MAXIMIZED.
FORECAST SOUNDINGS SUGGEST WARM SURFACE LAYER WILL KEEP PRECIP
LIQUID PAST MIDNIGHT BEFORE LOW LEVEL COLD ADVECTION KICKS
IN...CHANGING RAIN TO SNOW FROM NORTHWEST TO SOUTHEAST. BUT STILL
SURFACE AND BOUNDARY LAYER TEMPERATURES WILL BE SIGNIFICANTLY WARM
TO OFFER DOUBT WHETHER PRECIP WILL CHANGE TO ALL SNOW EXCEPT FOR
NORTHEAST NEBRASKA AND WEST CENTRAL IOWA. WHERE SNOW DOES
FALL...QPF LOOKS TO REMAIN UNDER A TENTH OF AN INCH WITH MELTING
OCCURRING AS WELL. THUS AMOUNTS OF A HALF INCH OR LESS ARE
FORECAST NORTH AND EAST OF THE OMAHA METRO AREA...WITH LITTLE
ACCUMULATION SOUTH AND WEST.
WINDS WILL ALSO KICK UP SIGNIFICANTLY OVERNIGHT...ESPECIALLY IN
NORTHEAST NEBRASKA. UNIDIRECTIONAL NORTHWESTERLY FLOW ACCOMPANIED
BY 50KT 850 JET...ALONG WITH LOW LEVEL INSTABILITY PROMOTING
MIXING OF BOUNDARY LAYER...SUGGEST WINDS OF 30 TO 45 MPH ARE
POSSIBLE BETWEEN MIDNIGHT AND MID SUNDAY MORNING. WILL ISSUE WIND
ADVISORY FOR PARTS OF OUR AREA TO COVER THIS.
PRECIPITATION SHOULD BE ENDING BY NOON SUNDAY...BUT STRONG COLD
ADVECTION WILL PERSIST DURING THE DAY. THUS TEMPERATURES WILL
PROBABLY REMAIN STEADY OF FALL MUCH OF THE DAY. HIGHS ONLY IN THE
30S ARE EXPECTED.
COOLDOWN BEHIND SYSTEM WILL BE BRIEF AS WINDS RETURN TO THE SOUTH OR
SOUTHWEST OVERNIGHT SUNDAY NIGHT AS ANOTHER SHORTWAVE MOVES ACROSS
THE NORTHERN PLAINS. TEMPS MAY RISE OVERNIGHT AFTER AN EVENING
LOW...THEN A WIND SHIFT BEHIND SURFACE TROUGH ASSOCIATED WITH
NORTHERN PLAINS SHORTWAVE WILL OCCUR EARLY MONDAY. GUSTY NORTHWEST
WINDS WILL PROMOTE DECENT MIXING MONDAY AFTERNOON WITH 850
TEMPERATURES IN THE 8-10C RANGE. HIGHS MONDAY AFTERNOON COULD REACH
60 IN OUR SOUTHWEST WITH PLENTY OF 50S ELSEWHERE.
A QUICK SHOT OF HIGH PRESSURE OVERHEAD TUESDAY MORNING WILL MOVE OFF
TO THE EAST...BRINGING SOUTHEASTERLY LOW LEVEL FLOW TUESDAY
AFTERNOON. THIS IS NORMALLY NOT A WARM WIND FOR US...SO TEMPS WILL
BE A GOOD 5 OR 10 DEGREES COOLER TUESDAY AFTERNOON DESPITE A SIMILAR-
TO-MONDAY LOW LEVEL TEMPERATURE PROFILE. STILL SHOULD SEE HIGHS IN
THE 50S MOST AREAS.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 324 PM CST SAT JAN 24 2015
ANOTHER WARM DAY WEDNESDAY WILL BE FOLLOWED BY COOLER TEMPERATURES
THROUGH THE END OF THE WEEK...AND LIKELY SIGNIFICANTLY COLDER BY
NEXT WEEKEND.
UPPER PATTERN WILL BECOME BRIEFLY ZONAL IN THE PLAINS ON WEDNESDAY
AS A PACIFIC SHORTWAVE APPROACHES FROM THE WEST. ANOTHER MILD DAY
WEDNESDAY IS FORECAST AHEAD OF THIS SHORTWAVE WITH SOUTH TO
SOUTHWEST FLOW PUMPING TEMPS BACK INTO THE 50S. SIGNIFICANT COOLING
IS EXPECTED BEHIND THIS WAVE WITH 850 TEMPERATURES DROPPING SOME 20C
BETWEEN WEDNESDAY AND THURSDAY AFTERNOONS. SOME LIGHT PRECIPITATION
IS POSSIBLE...BUT TRACK OF SURFACE LOW WILL BE WELL TO OUR
NORTHEAST. HIGH PRESSURE OVERHEAD THURSDAY WILL KEEP TEMPERATURES
FROM CLIMBING TOO FAR...WITH HIGHS STRUGGLING TO TOP 40. A LITTLE
WARMER FRIDAY AS SOUTH WINDS RETURN BRIEFLY AHEAD OF A STRONG COLD
FRONT DROPPING OUT OF THE NORTHERN PLAINS.
ECMWF AND GFS DIFFER GREATLY FOR FRIDAY NIGHT AND SATURDAY FORECAST.
GFS BRINGS A CLASSIC OVERRUNNING PATTERN TO THE PLAINS WITH
SIGNIFICANT SNOWFALL POSSIBLE. ECMWF KEEPS PRECIPITATION WELL SOUTH
OF OUR AREA AND SLAMS THE PLAINS WITH MINUS 20C 850 AIR. FOR NOW OUR
FORECAST WILL BLEND THESE TWO SCENARIOS WITH COLDER TEMPERATURES AND
A SMALL CHANCE FOR SNOW FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 547 PM CST SAT JAN 24 2015
CLIPPER SYSTEM MOVING ACROSS THE CENTRAL DAKOTAS IS STILL ON TRACK
TO MAKE A QUICK SWEEP ACROSS EASTERN NEBRASKA AND WESTERN IOWA
OVERNIGHT. BETWEEN 01Z AND 03Z EXPECT WINDS TO BECOME NORTHWEST
AND GUSTY...GUSTING 30KT TO 35KT AFTER 08Z. PERIODS OF -SHRA WILL
BEGIN AT KOFK BY 05Z SPREADING INTO KOMA AND KLNK BETWEEN 08Z AND
11Z. SOME SNOW SHOWERS WILL ALSO BE POSSIBLE AT ALL THREE TAF
SITES MAINLY BETWEEN 08Z AND 12Z. MVFR CIGS WILL SPREAD ACROSS AT
ALL THREE TAF SITES BETWEEN 05Z AND 11Z. EXPECT IMPROVEMENT BY MID
AFTERNOON AS DEEPER MOISTURE MOVES OUT OF THE AREA.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR
NEZ011-012-015>018-030>033-042-043-050-065.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...PEARSON
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
731 PM EST SAT JAN 24 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL PASS THROUGH THE REGION THIS EVENING
ASSOCIATED WITH A CANADIAN LOW PRESSURE SYSTEM PASSING WELL TO
THE NORTH. A COASTAL LOW PRESSURE SYSTEM WILL PROVIDE SOME
LINGERING SNOW SHOWERS OVER SOUTHERN VERMONT. COLD AIR ADVECTION
AHEAD OF A POTENTIAL STRONG SYSTEM EARLY NEXT WEEK WILL BRING COLD
OVERNIGHT LOWS AND DAYTIME HIGHS THROUGH NEXT WEEK. A POTENTIALLY
STRONG SYSTEM WILL BRING WIDESPREAD SNOW SHOWERS TO THE AREA
TUESDAY INTO WEDNESDAY NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
AS OF 624 PM EST SATURDAY...FORECAST GENERALLY HOLDING UP WELL,
BUT I DID MAKE SOME MINOR ADJUSTMENTS TO THE FORECAST IN TERMS OF
SKY COVER, POPS AND WEATHER ELEMENTS. I`VE TRIED TO BETTER SHOW
SKY TRENDS EVIDENT IN IR IMAGERY WHICH DEPICT AN AREA OF MOSTLY
CLEAR SKIES SANDWICHED BETWEEN LAYERS OF STRATUS ACROSS THE CT
VALLEY AND AHEAD OF AN ARCTIC FRONT ACROSS NORTHERN NEW YORK AND
THE NORTHERN CHAMPLAIN VALLEY. THAT WILL CONTINE TO FILL IN FROM W
TO E THIS EVENING.
FRANKTOWN ONTARIO RADAR DEPICTS AN AREA OF SNOW SHOWERS ACROSS
EASTERN ONTARIO AHEAD OF THE ARCTIC FRONT, WHICH PER RAP ANALYSES
IS STILL NORTHWEST OF OTTAWA. THESE WILL SPREAD INTO THE ST.
LAWRENCE VALLEY SHORTLY. FOR THAT REASON, I`VE OPTED TO GO WITH
AREAL COVERAGE WORDING. SOME LOWERED VISIBILITIES CAN BE EXPECTED
IN THESE SNOW SHOWERS, THOUGH I`M NOT ANTICIPATING ANY SNOW
SQUALLS AS CONVECTIVE DEPTH IS VERY SHALLOW (GENERALLY UNDER 1 KM
AGL AS PER BUFKIT SOUNDINGS). I`VE TIMED ARCTIC FRONT INTO THE
ST. LAWRENCE VALLEY AROUND MIDNIGHT TO 1 AM AND SWEEP FURTHER
SOUTHEAST ACROSS VERMONT INTO THE OVERNIGHT HOURS. STILL THINK
D-2" OF SNOW ACCUMULATION LOOKS PRETTY GOOD FOR THE OVERNIGHT.
ASIDE FROM MINOR TWEAKS TO TEMPS, I`VE MADE NO OTHER ADJUSTMENTS
TO THE GOING FORECAST.
&&
.SHORT TERM /7 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 342 PM EST SATURDAY...SUNDAY MORNING AN UPPER LEVEL RIDGE
WILL BUILD INTO THE REGION AND SURFACE HIGH PRESSURE WILL MOVE IN
RAPIDLY FROM THE WEST. THIS WILL CONTINUE THE SURGE OF COLD AIR
AND LEAVE THE AREA LOOKING AT MAX TEMPS IN THE MID TO LOW TEENS ON
SUNDAY WITH DRY WEATHER AND PARTLY CLOUDY SKIES. MONDAY THE BROAD
SURFACE HIGH WILL BE FIRMLY ENTRENCHED OVER THE REGION SO MONDAY
WILL BE ANOTHER QUITE COLD DAY UNDER MOSTLY CLEAR SKIES AND LIGHT
AND VARIABLE SURFACE WINDS UNDER SOUTHWEST FLOW ALOFT.
BY MONDAY NIGHT A DEEPENING UPPER LEVEL TROUGH OVER THE GREAT
LAKES WILL COMBINE WITH A DEVELOPING COASTAL SURFACE LOW PRESSURE
SYSTEM AND HAVE THE POTENTIAL TO BE A STRONG COASTAL STORM OFF THE
NEW ENGLAND COAST BY TUESDAY MORNING. THERE IS VERY GOOD
CONSENSUS AMONG MEDIUM RANGED MODELS THAT THE SYSTEM WILL DEVELOP
AND TRACK JUST OFF THE NEW ENGLAND COAST WHICH MEANS THAT
WIDESPREAD PRECIP LOOKS LIKELY FOR MOST OF THE AREA WHERE SOME OF
THE PRECIP WILL FALL AS SNOW. AT THIS POINT WITH THE VARIABLE
NATURE OF THE TRACK AND THE FACT THAT AS OF YESTERDAY THE ECWMF
WAS THE ONLY LONG RANGE MODEL WITH THE SYSTEM I`VE BEEN HESITANT
TO ADD IN FINE SCALE DETAILS TO THE FORECAST CONCERNING SNOWFALL
ACCUMULATION ON THE LEADING EDGE OF THE SYSTEM MONDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 341 PM EST SATURDAY...QUITE A CHANGE FROM 24 HOURS AGO...AS
ECMWF...GFS AND CANADIAN MODELS SHOW A LOW PRESSURE AREA BOMBING
OUT SOUTH OF NEW ENGLAND ON TUESDAY. MODELS SPREAD SNOW FURTHER
WEST INTO VERMONT AND INTO NORTHERN NEW YORK ON TUESDAY.
HOWEVER...MODELS DIFFER AS TO THE TRACK OF THIS LOW. ECMWF APPEARS
TO BE THE OUTLIER ON TUESDAY AS IT HAS THE LOW WEST-SOUTHWEST OF
THE BENCHMARK AT 18Z TUESDAY...WHILE THE OTHER MODELS ARE EAST-
NORTHEAST OF THE BENCHMARK BY 18Z TUESDAY. SNOW AMOUNTS AT THIS
TIME ARE STILL UNCERTAIN...GIVEN DIFFERENCES IN THE TRACK OF THE
LOW. HAVE OPTED TO GO HIGHER THAN THE SUPER-BLEND POPS ON TUESDAY
AND HAVE GONE WITH LIKELY POPS ACROSS ALL OF VERMONT AND THE
CHAMPLAIN VALLEY...AND CHANCE POPS ACROSS THE ADIRONDACKS AND
SAINT LAWRENCE VALLEY IN NORTHERN NEW YORK.
MODELS SHOW SNOW WINDING DOWN TUESDAY NIGHT AS LOW STARTS TO MOVE
NORTHEAST TOWARD NOVA SCOTIA. HOWEVER...HAVE STILL GONE HIGHER
THAN SUPER-BLEND POPS FOR TUESDAY NIGHT.
HIGH PRESSURE TO BUILD INTO THE REGION WEDNESDAY AND WEDNESDAY
NIGHT. A CLIPPER SYSTEM WILL MOVE EAST-SOUTHEAST FROM THE UPPER
MISSISSIPPI VALLEY AND WILL BE OFF THE SOUTHERN NEW ENGLAND COAST
ON FRIDAY. THUS...HAVE GONE WITH CHANCE POPS FOR SNOW FROM
THURSDAY THROUGH FRIDAY. ANOTHER SHOT OF ARCTIC AIR WILL MOVE INTO
THE REGION FRIDAY NIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD
SOUTHEAST FROM THE GREAT LAKES ON SATURDAY...WITH FAIR AND DRY
WEATHER EXPECTED.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
THROUGH 00Z MONDAY...A COLD FRONT APPROACHING FROM SERN ONTARIO
WILL BRING SCATTERED FLURRIES THROUGH THE FIRST HALF OF
TONIGHT...AND THEN PERIODS OF MVFR-IFR SNOW SHOWERS 06-12Z. ONLY
MINOR IMPACTS TO AVIATION GROUND OPERATIONS ANTICIPATED...WITH
SNOW ACCUMULATION AT THE TAF SITES GENERALLY LESS THAN 1 INCH.
SURFACE WINDS GENERALLY LIGHT W-NW...THEN INCREASING TO 10-15 KTS
WITH GUSTS TO 25 KTS TOWARD DAYBREAK AND THROUGH MUCH OF THE DAY
SUNDAY WITH STEEP LAPSE RATES AND STRONG P-GRADIENT BEHIND THE
FRONT. SKIES GENERALLY CLEAR LATE MORNING SUNDAY WITH A RETURN TO
VFR CONDITIONS.
OUTLOOK 00Z MONDAY THROUGH THURSDAY...
00Z MONDAY THROUGH 12Z TUESDAY...GENERALLY VFR WITH HIGH
PRESSURE.
12Z TUESDAY THROUGH 12Z WEDNESDAY...IFR/MVFR IN SNOW FROM
DEEPENING STORM OFF THE NEW ENGLAND COAST.
12Z WEDNESDAY THROUGH 18Z THURSDAY...MAINLY VFR CONDITIONS
EXPECTING AS RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION.
18Z THURSDAY THROUGH 00Z FRIDAY...DEVELOPING IFR/MVFR IN LIGHT
SNOW.
&&
.EQUIPMENT...
AS OF 106 PM EST FRIDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK WILL BE DOWN AT LEAST THROUGH MONDAY JANUARY
26TH. THIS IS DUE TO A PEDESTAL DYNAMIC FAULT. AN ELECTRONICS
TECHNICIAN HAS ORDERED NEW PARTS TO FIX THIS PROBLEM.
HOWEVER...THE NEW PARTS HAVE NOT ARRIVED AS OF THIS TIME AND THE
KTYX RADAR WILL LIKELY NOT BE RESTORED TO SERVICE UNTIL EARLY NEXT
WEEK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DEAL
NEAR TERM...DEAL
SHORT TERM...DEAL/LOCONTO
LONG TERM...WGH
AVIATION...BANACOS/WGH
EQUIPMENT...WGH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
625 PM EST SAT JAN 24 2015
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL PASS THROUGH THE REGION THIS EVENING
ASSOCIATED WITH A CANADIAN LOW PRESSURE SYSTEM PASSING WELL TO
THE NORTH. A COASTAL LOW PRESSURE SYSTEM WILL PROVIDE SOME
LINGERING SNOW SHOWERS OVER SOUTHERN VERMONT. COLD AIR ADVECTION
AHEAD OF A POTENTIAL STRONG SYSTEM EARLY NEXT WEEK WILL BRING COLD
OVERNIGHT LOWS AND DAYTIME HIGHS THROUGH NEXT WEEK. A POTENTIALLY
STRONG SYSTEM WILL BRING WIDESPREAD SNOW SHOWERS TO THE AREA
TUESDAY INTO WEDNESDAY NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
AS OF 624 PM EST SATURDAY...FORECAST GENERALLY HOLDING UP WELL,
BUT I DID MAKE SOME MINOR ADJUSTMENTS TO THE FORECAST IN TERMS OF
SKY COVER, POPS AND WEATHER ELEMENTS. I`VE TRIED TO BETTER SHOW
SKY TRENDS EVIDENT IN IR IMAGERY WHICH DEPICT AN AREA OF MOSTLY
CLEAR SKIES SANDWICHED BETWEEN LAYERS OF STRATUS ACROSS THE CT
VALLEY AND AHEAD OF AN ARCTIC FRONT ACROSS NORTHERN NEW YORK AND
THE NORTHERN CHAMPLAIN VALLEY. THAT WILL CONTINE TO FILL IN FROM W
TO E THIS EVENING.
FRANKTOWN ONTARIO RADAR DEPICTS AN AREA OF SNOW SHOWERS ACROSS
EASTERN ONTARIO AHEAD OF THE ARCTIC FRONT, WHICH PER RAP ANALYSES
IS STILL NORTHWEST OF OTTAWA. THESE WILL SPREAD INTO THE ST.
LAWRENCE VALLEY SHORTLY. FOR THAT REASON, I`VE OPTED TO GO WITH
AREAL COVERAGE WORDING. SOME LOWERED VISIBILITIES CAN BE EXPECTED
IN THESE SNOW SHOWERS, THOUGH I`M NOT ANTICIPATING ANY SNOW
SQUALLS AS CONVECTIVE DEPTH IS VERY SHALLOW (GENERALLY UNDER 1 KM
AGL AS PER BUFKIT SOUNDINGS). I`VE TIMED ARCTIC FRONT INTO THE
ST. LAWRENCE VALLEY AROUND MIDNIGHT TO 1 AM AND SWEEP FURTHER
SOUTHEAST ACROSS VERMONT INTO THE OVERNIGHT HOURS. STILL THINK
D-2" OF SNOW ACCUMULATION LOOKS PRETTY GOOD FOR THE OVERNIGHT.
ASIDE FROM MINOR TWEAKS TO TEMPS, I`VE MADE NO OTHER ADJUSTMENTS
TO THE GOING FORECAST.
&&
.SHORT TERM /7 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 342 PM EST SATURDAY...SUNDAY MORNING AN UPPER LEVEL RIDGE
WILL BUILD INTO THE REGION AND SURFACE HIGH PRESSURE WILL MOVE IN
RAPIDLY FROM THE WEST. THIS WILL CONTINUE THE SURGE OF COLD AIR
AND LEAVE THE AREA LOOKING AT MAX TEMPS IN THE MID TO LOW TEENS ON
SUNDAY WITH DRY WEATHER AND PARTLY CLOUDY SKIES. MONDAY THE BROAD
SURFACE HIGH WILL BE FIRMLY ENTRENCHED OVER THE REGION SO MONDAY
WILL BE ANOTHER QUITE COLD DAY UNDER MOSTLY CLEAR SKIES AND LIGHT
AND VARIABLE SURFACE WINDS UNDER SOUTHWEST FLOW ALOFT.
BY MONDAY NIGHT A DEEPENING UPPER LEVEL TROUGH OVER THE GREAT
LAKES WILL COMBINE WITH A DEVELOPING COASTAL SURFACE LOW PRESSURE
SYSTEM AND HAVE THE POTENTIAL TO BE A STRONG COASTAL STORM OFF THE
NEW ENGLAND COAST BY TUESDAY MORNING. THERE IS VERY GOOD
CONSENSUS AMONG MEDIUM RANGED MODELS THAT THE SYSTEM WILL DEVELOP
AND TRACK JUST OFF THE NEW ENGLAND COAST WHICH MEANS THAT
WIDESPREAD PRECIP LOOKS LIKELY FOR MOST OF THE AREA WHERE SOME OF
THE PRECIP WILL FALL AS SNOW. AT THIS POINT WITH THE VARIABLE
NATURE OF THE TRACK AND THE FACT THAT AS OF YESTERDAY THE ECWMF
WAS THE ONLY LONG RANGE MODEL WITH THE SYSTEM I`VE BEEN HESITANT
TO ADD IN FINE SCALE DETAILS TO THE FORECAST CONCERNING SNOWFALL
ACCUMULATION ON THE LEADING EDGE OF THE SYSTEM MONDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 341 PM EST SATURDAY...QUITE A CHANGE FROM 24 HOURS AGO...AS
ECMWF...GFS AND CANADIAN MODELS SHOW A LOW PRESSURE AREA BOMBING
OUT SOUTH OF NEW ENGLAND ON TUESDAY. MODELS SPREAD SNOW FURTHER
WEST INTO VERMONT AND INTO NORTHERN NEW YORK ON TUESDAY.
HOWEVER...MODELS DIFFER AS TO THE TRACK OF THIS LOW. ECMWF APPEARS
TO BE THE OUTLIER ON TUESDAY AS IT HAS THE LOW WEST-SOUTHWEST OF
THE BENCHMARK AT 18Z TUESDAY...WHILE THE OTHER MODELS ARE EAST-
NORTHEAST OF THE BENCHMARK BY 18Z TUESDAY. SNOW AMOUNTS AT THIS
TIME ARE STILL UNCERTAIN...GIVEN DIFFERENCES IN THE TRACK OF THE
LOW. HAVE OPTED TO GO HIGHER THAN THE SUPER-BLEND POPS ON TUESDAY
AND HAVE GONE WITH LIKELY POPS ACROSS ALL OF VERMONT AND THE
CHAMPLAIN VALLEY...AND CHANCE POPS ACROSS THE ADIRONDACKS AND
SAINT LAWRENCE VALLEY IN NORTHERN NEW YORK.
MODELS SHOW SNOW WINDING DOWN TUESDAY NIGHT AS LOW STARTS TO MOVE
NORTHEAST TOWARD NOVA SCOTIA. HOWEVER...HAVE STILL GONE HIGHER
THAN SUPER-BLEND POPS FOR TUESDAY NIGHT.
HIGH PRESSURE TO BUILD INTO THE REGION WEDNESDAY AND WEDNESDAY
NIGHT. A CLIPPER SYSTEM WILL MOVE EAST-SOUTHEAST FROM THE UPPER
MISSISSIPPI VALLEY AND WILL BE OFF THE SOUTHERN NEW ENGLAND COAST
ON FRIDAY. THUS...HAVE GONE WITH CHANCE POPS FOR SNOW FROM
THURSDAY THROUGH FRIDAY. ANOTHER SHOT OF ARCTIC AIR WILL MOVE INTO
THE REGION FRIDAY NIGHT AND SATURDAY. HIGH PRESSURE WILL BUILD
SOUTHEAST FROM THE GREAT LAKES ON SATURDAY...WITH FAIR AND DRY
WEATHER EXPECTED.
&&
.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
THROUGH 18Z SUNDAY...MAINLY VFR CONDITIONS EXPECTED THROUGH THE
PERIOD...EXCEPT FOR MVFR CEILINGS IN THE SAINT LAWRENCE VALLEY IN
NORTHERN NEW YORK. EXPECTING CEILINGS TO LOWER LATER TODAY AND
TONIGHT AS AN ARCTIC COLD FRONT APPROACHES FROM CANADA. EXPECTING
A PERIOD OF MVFR/IFR CONDITIONS IN SNOW SHOWERS WITH THIS ARCTIC
COLD FRONT FROM 04Z-12Z SUNDAY ACROSS NORTHERN NEW YORK AND FROM
07Z-14Z SUNDAY ACROSS VERMONT. EXPECTING SURFACE WIND GUSTS FROM
THE NORTHWEST AT OR ABOVE 20 KNOTS FROM 06Z-14Z SUNDAY THROUGH
18Z SUNDAY.
OUTLOOK 18Z SUNDAY THROUGH THURSDAY...
18Z SUNDAY THROUGH 12Z TUESDAY...GENERALLY VFR WITH HIGH
PRESSURE.
12Z TUESDAY THROUGH 12Z WEDNESDAY...IFR/MVFR IN SNOW FROM
DEEPENING STORM OFF THE NEW ENGLAND COAST.
12Z WEDNESDAY THROUGH 18Z THURSDAY...MAINLY VFR CONDITIONS
EXPECTING AS RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION.
18Z THURSDAY THROUGH 00Z FRIDAY...DEVELOPING IFR/MVFR IN LIGHT
SNOW.
&&
.EQUIPMENT...
AS OF 106 PM EST FRIDAY...THE KTYX 88D DOPPLER RADAR LOCATED IN
NORTHERN NEW YORK WILL BE DOWN AT LEAST THROUGH MONDAY JANUARY
26TH. THIS IS DUE TO A PEDESTAL DYNAMIC FAULT. AN ELECTRONICS
TECHNICIAN HAS ORDERED NEW PARTS TO FIX THIS PROBLEM.
HOWEVER...THE NEW PARTS HAVE NOT ARRIVED AS OF THIS TIME AND THE
KTYX RADAR WILL LIKELY NOT BE RESTORED TO SERVICE UNTIL EARLY NEXT
WEEK.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DEAL
NEAR TERM...DEAL
SHORT TERM...DEAL/LOCONTO
LONG TERM...WGH
AVIATION...WGH
EQUIPMENT...WGH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 PM EST FRI JAN 23 2015
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK NORTHEAST OVER THE
EASTERN CAROLINA`S TONIGHT AND EARLY SATURDAY. THE MAIN COLD FRONT
WILL PUSH THROUGH OUR REGION SATURDAY. ANOTHER COLD FRONT WILL
APPROACH FROM THE NORTHWEST SUNDAY NIGHT AND EARLY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM FRIDAY...
COLD RAINY WEATHER TONIGHT INTO EARLY SATURDAY...
SURFACE HIGH PRESSURE CONTINUED TO RETREAT OFFSHORE THIS AFTERNOON
AS LOW PRESSURE TRACKED ALONG THE GULF COAST STATES. RAIN BECAME
WIDESPREAD ACROSS THE CAROLINA`S TODAY WITH SOME AREAS REPORTING A
BRIEF MIXTURE OF SLEET AND RAIN AT THE PRECIPIATION ONSET FROM THE
TRIAD TO ROXBORO. THE HIGH TO THE NORTH WAS RETREATING RAPIDLY
OFFSHORE THIS MORNING WHICH QUICKLY CUT OFF ANY SOURCE OF COLD AIR
INTO OUR REGION. INSTEAD... A SOUTHEAST TO SOUTH FLOW INCREASED JUST
ABOVE THE SURFACE WITH RAPIDLY MOISTENING AND WARMING COLUMN OUT IN
ADVANCE OF THE APPROACHING DEEP MID/UPPER TROUGH OVER THE LOWER
MISSISSIPPI VALLEY. AS THIS TROUGH APPROACHES... THEN CROSSES OVER
THE REGION TONIGHT... THE SURFACE LOW CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE WILL TURN NORTHEAST ALONG THE COASTAL PLAIN OF
GA/SC/NC OVERNIGHT. WITH SURFACE TEMPERATURES SAFELY ABOVE FREEZING
AND WITH SATURATION IN PLACE AT THE SURFACE... AND EVEN CONTINUED
WARMING ALOFT... PLAIN RAIN WILL CONTINUE TO BE DOMINATE OVER NC.
THE TEMPERATURES SHOULD BE NEAR THE LOWS ALREADY THIS AFTERNOON (IN
THE MID 30S)... WITH READINGS EXPECTED TO REMAIN STEADY OR SLOWLY
RISE (ESPECIALLY ALONG I-95 OVERNIGHT). THE RELATIVELY FAST MOVEMENT
OF THE LOW PRESSURE (REACHING NEAR ELIZABETH CITY BY 09Z/SAT) SHOULD
COMBINE WITH THE STRONG IN-SITU COLD AIR DAMMING EVENT OVER THE
PIEDMONT TO LIMIT THE WESTWARD OR INLAND PUSH OF THE COASTAL FRONT.
TEMPS OVER THE COASTAL PLAIN MAY WELL RISE TO AROUND 50 LATE
TONIGHT... WHILE READINGS REMAIN IN THE MID 30S OVER THE NW
PIEDMONT.
QPF MAY BE A BIT LESS THAN EARLIER ANTICIPATED AS THE DEEP
CONVECTION CONTINUES TO BE ROLLING ALONG FROM THE GULF TO FLORIDA...
HAVING SOME NEGATIVE IMPACT ON QPF INLAND. JUST HOW MUCH THIS
AFFECTS OUR STORM TOTALS IS OF LOW CONFIDENCE. THE LATEST HRRR AND
THE OPERATIONAL MODELS GENERALLY DEPICT ABOUT 1/3 LESS QPF THAN THE
EARLIER 1-2 INCH FORECAST. WE WILL TREND A BIT LOWER - WHICH WOULD
LESSEN THE RUNOFF POTENTIAL FOR OUR REGION - WHICH WAS NOT
ANTICIPATED TO CREATE MAJOR PROBLEMS EVEN WITH 1-2 INCHES STORM
TOTALS. THE HRRR... WHICH ACTUALLY VERIFIED WELL WITH P-TYPE AND
TIMING TODAY... INDICATES THE MAIN BACK EDGE OF THE LARGE RAIN
SHIELD MAY EDGE INTO THE SW PIEDMONT BY AT LEAST 06Z AND THE REST OF
THE REGION BY 12Z/SAT. HOWEVER... THERE MAY BE ADDITIONAL "FILL IN"
OF ANY DRY HOLES INLAND SC/NC IF/WHEN THE DEEP SOUTH/FLORIDA
CONVECTION DISSIPATES. THE THUNDERSTORM THREAT IS MINIMAL OVER OUR
REGION GIVEN THE TRACK OF THE LOW AROUND OR JUST EAST OF I-95... AS
MOST OF THE REGION WILL REMAIN IN THE CAD REGION. THE HEAVIEST QPF
AROUND 1 TO 1.5 INCHES IS STILL FORECAST OVER AND EAST OF THE
TRIANGLE... WITH AMOUNTS LIKELY 0.50 TO 0.75 IN THE NW. -BADGETT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 230 PM FRIDAY...
THE MAIN RAIN EVENT WILL END BETWEEN 09Z/15Z SW TO NE ACROSS OUR
REGION SATURDAY AS THE STORM BOMBS AS IT MOVES AWAY FROM DELMARVA.
THE TRAILING DEFORMATION BAND OF PRECIPITATION WITH THE MID LEVEL
LOW IS EXPECTED TO WEAKEN AND DISSIPATE AS IT SPREADS EAST FROM
KY/TN/WVA INTO WESTERN VA AND NORTH-CENTRAL NC SATURDAY. IN
ADDITION... THE BOUNDARY LAYER WINDS WILL SHIFT TO THE WNW AND
INCREASE TO 10-20 MPH IN DOWNSLOPE FASHION DURING THE AFTERNOON.
THIS SHOULD LEAD TO SHARP CLEARING FROM OFF THE BLUE RIDGE INTO THE
PIEDMONT DURING THE AFTERNOON. SKIES SHOULD BECOME PARTLY SUNNY DOWN
EAST LATE IN THE AFTERNOON. HIGHS SHOULD RETURN INTO THE 45-55 RANGE
NW TO SE. THE SKIES SHOULD REMAIN MOSTLY CLEAR TO PARTLY CLOUDY
SATURDAY NIGHT. LOWS 30-35 WITH DIMINISHING NW BREEZES IN THE
EVENING.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 235 PM FRIDAY...
SUNDAY: FAIR WEATHER EXPECTED DURING THE DAYTIME HOURS SUNDAY WITH A
FLAT RIDGE OVER OUR AREA...BETWEEN SATURDAY`S DEPARTING SHORT
WAVE...AND THE NEXT SHORT WAVE THAT WILL BE DROPPING SE ACROSS THE
OH VALLEY. FORECAST SOUNDINGS SUGGEST NEAR-NORMAL HIGHS IN THE LOWER
TO MID 50S. SUNDAY NIGHT...THE AFOREMENTIONED SHORT WAVE WILL CROSS
THE MOUNTAINS WHILE THE ASSOC SFC LOW MOVES FROM THE LOWER OH VALLEY
SUNDAY EVENING EWD TO CENTRAL NC BY 12Z MONDAY. A PLUME OF MOISTURE
AND PERHAPS A NARROW BAND OF LIGHT SHOWERS ALONG THE ATTENDANT COLD
FRONT AND INVOF OF THE TRIPLE POINT WILL MOVE ACROSS CENTRAL NC IN
THE PREDAWN HOURS. DESPITE NOTABLE COOLING ALOFT...ALL FORECAST
SOUNDINGS ACROSS CENTRAL NC SHOW LOW LEVELS WARM ENOUGH FOR ALL RAIN
WITH THIS BAND OF SHOWERS...EVEN ACROSS THE TRIAD. LOWS MONDAY
MORNING IN THE MID TO UPPER 30S.
DURING THE DAYTIME MONDAY...THE MID LEVEL TROUGH AXIS IS PROGGED TO
CROSS CENTRAL NC...ALONG WITH THE TRIPLE POINT LOW TAKING OVER AND
STRENGTHENING OFFSHORE OF KHSE. A FEW ADDITIONAL SHOWERS WILL BE
POSSIBLE ACROSS OUR AREA (ESP OUR NORTHERN/NE ZONES) AS THE TROUGH
AXIS MOVES ACROSS...BUT MOISTURE IS MODEST AND CONSENSUS MODEL QPF
FOR THE DAYTIME MONDAY IS WELL UNDER ONE TENTH INCH. WITH THE BL
WIND SHIFT TO N AND THE START OF LOW LEVEL CAA NOT OCCURRING UNTIL
AFTER NOON...BOUNDARY LAYER TEMPS WILL BE WARM ENOUGH SUCH THAN ANY
PRECIP DURING THE DAYTIME MONDAY SHOULD BE ALL RAIN. BY 00Z
TUESDAY...FORECAST SOUNDINGS SUGGEST ENOUGH LOW LEVEL COOLING WILL
HAVE OCCURRED THAT ANY LINGERING SHOWERS ACROSS OUR NE ZONES (INVOF
OF DEEPER MOISTURE UNDER THE TROUGH AXIS) MAY MIX WITH OR CHANGE TO
SNOW SHOWERS. BUT AGAIN...KEEP IN MIND THAT MODEL QPF VALUES ARE
VERY LIGHT...SO PERHAPS ONLY FLURRIES OR VERY LIGHT SNOW SHOWERS
WITH NO ACCUM...IF ANY PRECIP AT ALL. AS ALWAYS THE CASE WITH THESE
SYSTEMS...IT`S A CLOSE TIMING ISSUE BETWEEN ARRIVAL OF COLDER AIR
AND DEPARTURE OF MOISTURE.
MONDAY NIGHT...ANOTHER TRAILING SHORT WAVE IS PROGGED TO DIVE SOUTH
FROM THE GREAT LAKES REGION...REACHING THE MID ATLANTIC REGION BY
TUESDAY MORNING OR AFTERNOON. WHILE THE AIRMASS ACROSS OUR AREA BY
THEN WOULD BE COLD ENOUGH FOR SNOW...THE DEEPEST MOISTURE AND BEST
CHANCE FOR ANY PRECIP APPEARS TO REMAIN TO OUR NORTH AND EAST PER
GFS...OR LITTLE IF ANY MOISTURE AT ALL ACROSS OUR AREA PER ECMWF.
FOR NOW...WILL KEEP POPS LOW ACROSS OUR AREA GIVEN LOW CONFIDENCE.
HIGHS ON TUESDAY WILL BE DEPENDENT ON PRECIP CHANCES...BUT FOR NOW
WILL MAINTAIN LOWER 40S.
FAIR WEATHER WEDNESDAY THROUGH EARLY THURSDAY IN THE WAKE OF THE
DEPARTING TROUGH...BUT TEMPS BELOW NORMAL THANKS TO DEEP N-NW FLOW.
YET ANOTHER SHORT WAVE WILL QUICKLY APPROACH LATE THURSDAY AND MOVE
ACROSS EARLY FRIDAY. RIGHT NOW THE MODELS SUGGEST A DRY TROUGH
PASSAGE THANKS TO ANTECEDENT DRY NW FLOW.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 215 PM FRIDAY...
AVIATION CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE
AFTERNOON AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST
SOUTHEASTERLY TO SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH
LIGHTER EASTERLY WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE
OF LOW LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS THIS
EVENING. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH EARLY SATURDAY. WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY MID TO
LATE MORNING IN THE NW... AND IN THE EAST BY EARLY AFTERNOON... AS
THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC COAST AND AWAY
FROM CENTRAL NC.
VFR CONDITIONS ARE EXPECTED SUNDAY INTO MID NEXT WEEK AS MOST
WEATHER MAKERS SHOULD REMAIN JUST TO OUR NORTH.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...NP
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 PM EST FRI JAN 23 2015
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK NORTHEAST OVER THE
EASTERN CAROLINA`S TONIGHT AND EARLY SATURDAY. THE MAIN COLD FRONT
WILL PUSH THROUGH OUR REGION SATURDAY. ANOTHER COLD FRONT WILL
APPROACH FROM THE NORTHWEST SUNDAY NIGHT AND EARLY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM FRIDAY...
COLD RAINY WEATHER TONIGHT INTO EARLY SATURDAY...
SURFACE HIGH PRESSURE CONTINUED TO RETREAT OFFSHORE THIS AFTERNOON
AS LOW PRESSURE TRACKED ALONG THE GULF COAST STATES. RAIN BECAME
WIDESPREAD ACROSS THE CAROLINA`S TODAY WITH SOME AREAS REPORTING A
BRIEF MIXTURE OF SLEET AND RAIN AT THE PRECIPIATION ONSET FROM THE
TRIAD TO ROXBORO. THE HIGH TO THE NORTH WAS RETREATING RAPIDLY
OFFSHORE THIS MORNING WHICH QUICKLY CUT OFF ANY SOURCE OF COLD AIR
INTO OUR REGION. INSTEAD... A SOUTHEAST TO SOUTH FLOW INCREASED JUST
ABOVE THE SURFACE WITH RAPIDLY MOISTENING AND WARMING COLUMN OUT IN
ADVANCE OF THE APPROACHING DEEP MID/UPPER TROUGH OVER THE LOWER
MISSISSIPPI VALLEY. AS THIS TROUGH APPROACHES... THEN CROSSES OVER
THE REGION TONIGHT... THE SURFACE LOW CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE WILL TURN NORTHEAST ALONG THE COASTAL PLAIN OF
GA/SC/NC OVERNIGHT. WITH SURFACE TEMPERATURES SAFELY ABOVE FREEZING
AND WITH SATURATION IN PLACE AT THE SURFACE... AND EVEN CONTINUED
WARMING ALOFT... PLAIN RAIN WILL CONTINUE TO BE DOMINATE OVER NC.
THE TEMPERATURES SHOULD BE NEAR THE LOWS ALREADY THIS AFTERNOON (IN
THE MID 30S)... WITH READINGS EXPECTED TO REMAIN STEADY OR SLOWLY
RISE (ESPECIALLY ALONG I-95 OVERNIGHT). THE RELATIVELY FAST MOVEMENT
OF THE LOW PRESSURE (REACHING NEAR ELIZABETH CITY BY 09Z/SAT) SHOULD
COMBINE WITH THE STRONG IN-SITU COLD AIR DAMMING EVENT OVER THE
PIEDMONT TO LIMIT THE WESTWARD OR INLAND PUSH OF THE COASTAL FRONT.
TEMPS OVER THE COASTAL PLAIN MAY WELL RISE TO AROUND 50 LATE
TONIGHT... WHILE READINGS REMAIN IN THE MID 30S OVER THE NW
PIEDMONT.
QPF MAY BE A BIT LESS THAN EARLIER ANTICIPATED AS THE DEEP
CONVECTION CONTINUES TO BE ROLLING ALONG FROM THE GULF TO FLORIDA...
HAVING SOME NEGATIVE IMPACT ON QPF INLAND. JUST HOW MUCH THIS
AFFECTS OUR STORM TOTALS IS OF LOW CONFIDENCE. THE LATEST HRRR AND
THE OPERATIONAL MODELS GENERALLY DEPICT ABOUT 1/3 LESS QPF THAN THE
EARLIER 1-2 INCH FORECAST. WE WILL TREND A BIT LOWER - WHICH WOULD
LESSEN THE RUNOFF POTENTIAL FOR OUR REGION - WHICH WAS NOT
ANTICIPATED TO CREATE MAJOR PROBLEMS EVEN WITH 1-2 INCHES STORM
TOTALS. THE HRRR... WHICH ACTUALLY VERIFIED WELL WITH P-TYPE AND
TIMING TODAY... INDICATES THE MAIN BACK EDGE OF THE LARGE RAIN
SHIELD MAY EDGE INTO THE SW PIEDMONT BY AT LEAST 06Z AND THE REST OF
THE REGION BY 12Z/SAT. HOWEVER... THERE MAY BE ADDITIONAL "FILL IN"
OF ANY DRY HOLES INLAND SC/NC IF/WHEN THE DEEP SOUTH/FLORIDA
CONVECTION DISSIPATES. THE THUNDERSTORM THREAT IS MINIMAL OVER OUR
REGION GIVEN THE TRACK OF THE LOW AROUND OR JUST EAST OF I-95... AS
MOST OF THE REGION WILL REMAIN IN THE CAD REGION. THE HEAVIEST QPF
AROUND 1 TO 1.5 INCHES IS STILL FORECAST OVER AND EAST OF THE
TRIANGLE... WITH AMOUNTS LIKELY 0.50 TO 0.75 IN THE NW. -BADGETT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 230 PM FRIDAY...
THE MAIN RAIN EVENT WILL END BETWEEN 09Z/15Z SW TO NE ACROSS OUR
REGION SATURDAY AS THE STORM BOMBS AS IT MOVES AWAY FROM DELMARVA.
THE TRAILING DEFORMATION BAND OF PRECIPITATION WITH THE MID LEVEL
LOW IS EXPECTED TO WEAKEN AND DISSIPATE AS IT SPREADS EAST FROM
KY/TN/WVA INTO WESTERN VA AND NORTH-CENTRAL NC SATURDAY. IN
ADDITION... THE BOUNDARY LAYER WINDS WILL SHIFT TO THE WNW AND
INCREASE TO 10-20 MPH IN DOWNSLOPE FASHION DURING THE AFTERNOON.
THIS SHOULD LEAD TO SHARP CLEARING FROM OFF THE BLUE RIDGE INTO THE
PIEDMONT DURING THE AFTERNOON. SKIES SHOULD BECOME PARTLY SUNNY DOWN
EAST LATE IN THE AFTERNOON. HIGHS SHOULD RETURN INTO THE 45-55 RANGE
NW TO SE. THE SKIES SHOULD REMAIN MOSTLY CLEAR TO PARTLY CLOUDY
SATURDAY NIGHT. LOWS 30-35 WITH DIMINISHING NW BREEZES IN THE
EVENING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 215 PM FRIDAY...
AVIATION CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE
AFTERNOON AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST
SOUTHEASTERLY TO SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH
LIGHTER EASTERLY WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE
OF LOW LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS THIS
EVENING. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH EARLY SATURDAY. WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY MID TO
LATE MORNING IN THE NW... AND IN THE EAST BY EARLY AFTERNOON... AS
THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC COAST AND AWAY
FROM CENTRAL NC.
VFR CONDITIONS ARE EXPECTED SUNDAY INTO MID NEXT WEEK AS MOST
WEATHER MAKERS SHOULD REMAIN JUST TO OUR NORTH.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...MWS
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
900 AM EST FRI JAN 23 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 AM FRIDAY...
THE 12Z/GSO SOUNDING WAS WELL REPRESENTATIVE OF THE CURRENT
TEMPERATURE PROFILE THROUGHOUT THE NORTHWEST PIEDMONT. THIS PROFILE
IS SUPPORTIVE OF BRIEF/NUISANCE LIGHT SNOW/SLEET MIXED WITH THE
RAIN AT PRECIP ONSET THIS MORNING IN THE NW PIEDMONT. HOWEVER...
SURFACE TEMPERATURES ARE WELL INTO THE 30S (ABOVE FREEZING)... AND
THE WET BULB TEMPERATURES ALSO JUST ABOVE FREEZING IN
FORSYTH AND NW GUILFORD INTO PERSON (OUR COLDEST COUNTIES). RADAR
INDICATED PRECIPITATION WAS RAPIDLY DEVELOPING OVER WESTERN NORTH
CAROLINA. THE PRECIPITATION WAS FALLING AS A LIGHT MIXTURE OF
SNOW/SLEET OVER THE NORTHERN MOUNTAINS AND NORTHERN FOOTHILLS...
WITH A LIGHT SNOW/SLEET/RAIN MIXTURE INTO DAVIDSON/FORSYTH COUNTIES.
IT IS ALONG THE LEADING EDGE OF THE PRECIPITATION SHIELD WHERE JUST
ENOUGH COLD DRY AIR WAS IN PLACE OVER NW NC COURTESY OF THE 1028 MB
SURFACE HIGH PRESSURE OVER PA... EXTENDING INTO NC/SC. THIS HIGH IS
RAPIDLY RETREATING AND THIS IS VERY UNFAVORABLE FOR ADDITIONAL COLD
DRY AIR DELIVERY INTO OUR REGION TO SUPPORT ANY SNOW/SLEET
ACCUMULATION IN OUR REGION. THE WARMING ALOFT WILL SWEEP IN FROM THE
SOUTH AND EAST QUICKLY TAKING TEMPERATURES INTO THE 40S AT 5K FEET
THIS AFTERNOON. THIS WILL END ANY SNOW/SLEET... AND KEEP IT AS A
NUISANCE ON THE LEADING EDGE OF THE EXPANDING PRECIP FIELD. ONCE WE
REACH SATURATION IN THE BOUNDARY LAYER... FORECAST WET BULBS ARE TO
REMAIN IN THE 33-35 RANGE TODAY.
THEREFORE... BOTTOM LINE... LIGHT SNOW/SLEET/RAIN MIX AT
PRECIPITATION ONSET IN THE NW AND N PIEDMONT... ROUGHLY WEST AND
NORTH OF A LINE FROM DAVIDSON AND RANDOLPH COUNTIES NE TO PERSON
COUNTY... NO SNOW/SLEET ACCUMULATION EXPECTED. AS THE COLUMN
SATURATES WITH THE PRECIPITATION FALLING FOR 1-3 HOURS... THE
PRECIPITATION WILL BE ALL RAIN WITH TEMPS EXPECTED TO HOLD NEAR THE
WET BULB READINGS IN THE MID 30S THROUGHOUT THE TRIAD REGION. THIS
IS SAFELY ABOVE FREEZING. THEN OVERNIGHT... TEMPS WILL REMAIN STEADY
OF EVEN RISE A FEW DEGREES DUE TO THE OVERWHELMING WARMING ALOFT AND
RAIN. -BADGETT
PREVIOUS DISCUSSION ISSUED AT 300 AM...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE OF LOW LEVEL WIND
SHEAR CONDITIONS AT EASTERN TERMINALS THIS EVENING. PERIODS OF RAIN
AND DRIZZLE...AND LIFR CONDITIONS...WILL CONTINUE OVERNIGHT...AS THE
LOW PRESSURE SYSTEM TRACKS JUST INLAND OF THE COAST OF THE
CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA SUN NIGHT-MON NIGHT...THE LATTER OF WHICH COULD
MIX WITH OR CHANGE TO LIGHT SNOW AS COLDER TEMPERATURES ARRIVE BY
MON EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BADGETT/BLS
SHORT TERM...BLS/MWS
LONG TERM...MWS
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
652 AM EST FRI JAN 23 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE OF LOW LEVEL WIND
SHEAR CONDITIONS AT EASTERN TERMINALS THIS EVENING. PERIODS OF RAIN
AND DRIZZLE...AND LIFR CONDITIONS...WILL CONTINUE OVERNIGHT...AS THE
LOW PRESSURE SYSTEM TRACKS JUST INLAND OF THE COAST OF THE
CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA SUN NIGHT-MON NIGHT...THE LATTER OF WHICH COULD
MIX WITH OR CHANGE TO LIGHT SNOW AS COLDER TEMPERATURES ARRIVE BY
MON EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BLS
SHORT TERM...BLS/MWS
LONG TERM...MWS
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
349 AM EST FRI JAN 23 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A LIKELY PROBABILITY OF LOW
LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS ROUGHLY BETWEEN 22-
04Z. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: SHOWERS WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA LATE SUN NIGHT-MON....AND POSSIBLY AGAIN ON TUE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BLS
SHORT TERM...BLS/MWS
LONG TERM...MWS
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
335 AM EST FRI JAN 22 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 150 PM THURSDAY...
LATE WEEKEND THROUGH NEXT WEEK WILL FEATURE HIGHLY AMPLIFIED MID
LEVEL FLOW AND COOLER TEMPERATURES AFTER A BRIEF PERIOD OF
SUBSIDENCE ON SUNDAY WHICH WILL ALLOW TEMPS TO REACH THE UPPER 40S
AND LOWER 50S. IN THE ENSUING NORTHWEST FLOW REGIME...AN INITIAL
SHORT WAVE WILL BE DIVING SOUTHEAST THROUGH THE OHIO VALLEY SUNDAY
NIGHT...GRAZING NORTH CAROLINA ON MONDAY. THIS WILL BE FOLLOWED
QUICKLY BY ANOTHER REINFORCING IMPULSE ON TUESDAY...BUT DETAILS AND
TIMING ISSUES THROW A LOT OF UNCERTAINTY INTO THE FORECAST AT THIS
POINT. THESE TWO SYSTEMS WILL BE LIMITED TO THE MOISTURE THAT THEY
BRING WITH THEM...WHICH WILL PRODUCE WIDESPREAD CLOUDINESS...BUT
ONLY LOW PRECIP CHANCES AND AT THIS POINT WILL BE LIMITING POPS TO
AROUND 30 PERCENT ACROSS THE NORTHERN TIER. IF SUFFICIENT MOISTURE
WITH THE INITIAL SHORT WAVE ARRIVES SUNDAY NIGHT THERE COULD BE SOME
LIGHT MIXED PRECIP ACROSS THE NORTHERN TIER IN THE PRE-DAWN TO EARLY
MONDAY MORNING BEFORE TEMPERATURES NEAR FREEZING WARM INTO THE UPPER
30S BY MID MORNING. WILL HAVE A SMALL POP FOR RAIN SHOWERS ON MONDAY
AREA-WIDE WITH HIGHS FROM THE MID 40S NORTH TO PERHAPS SOME LOWER
50S SOUTHEAST.
COLD AIR ADVECTION BEHIND THIS SHORT WAVE WILL KICK IN MONDAY NIGHT
AND MINS WILL FALL INTO THE UPPER 20S NORTH TO AROUND FREEZING
SOUTH. THERE IS LESS CONFIDENCE WITH TIMING BUT ALSO LESS POTENTIAL
FOR PRECIP WITH THE SECOND IMPULSE DIGGING TOWARDS THE AREA ON
MONDAY NIGHT AND TUESDAY. AT THIS POINT WILL MAINTAIN ONGOING SLIGHT
CHANCE POPS LIMITED TO MONDAY NIGHT. IF WE GET PRECIP...THERE COULD
BE A CHANGE OVER TO A MIXTURE OF VERY LIGHT RAIN AND SNOW SHOWERS AS
TEMPS FALL BELOW FREEZING MONDAY NIGHT. WILL KEEP POPS OUT OF THE
FORECAST TUESDAY FOR NOW GIVEN INCREASING UNCERTAINTY WITH TIME IN
THE NORTHWEST FLOW PATTERN. TUESDAY HIGHS WILL BE FROM 40 TO 45.
THE UPPER TROF SHIFTS OFFSHORE BY LATE WEDNESDAY...WITH A SLIGHT
WARMUP EXPECTED TOWARDS LATE WEEK AS HEIGHTS INCREASE WITH RIDGING
ALOFT AND PLENTIFUL SUNSHINE ON THURSDAY. HIGHS WEDNESDAY WILL
STRUGGLE TO GET OUT OF THE MID 40S...WARMING TO THE UPPER 40S TO
LOWER 50S THURSDAY...WHICH IS ONLY SLIGHTLY BELOW NORMAL.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A LIKELY PROBABILITY OF LOW
LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS ROUGHLY BETWEEN 22-
04Z. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: SHOWERS WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA LATE SUN NIGHT-MON....AND POSSIBLY AGAIN ON TUE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BLS
SHORT TERM...BLS/MWS
LONG TERM...MLM
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
937 PM CST SAT JAN 24 2015
.UPDATE...
ISSUED AT 931 PM CST SAT JAN 24 2015
AT 914 PM BISMARCK ASOS SURFACE OBS CHANGED TO RAIN FROM SNOW.
DUAL POLE PRODUCTS SUGGEST MIXED PRECIPITATION RAIN AND SNOW AS
THE CORRELATION COEFFICIENT FALLS BELOW 80 IN A NARROW BAND OVER
BISMARCK. ALTHOUGH RAIN...SEE THE VERY END OF THE PRECIPITATION
SHORTLY AS ITS ONLY A BAND ABOUT 10 MILES WIDE. FOR THIS FORECAST
WILL END THE PRECIPITATION SOONER ACROSS THE CENTRAL. WILL
CONTINUE LIGHT SNOW MOST OF THE NIGHT EAST.
UPDATE ISSUED AT 702 PM CST SAT JAN 24 2015
WIND ADVISORY HAS EXPIRED. EMPHASIZED THE EVENING LIGHT SNOW SOUTH
CENTRAL WITH DEFINITE POPS.
UPDATE ISSUED AT 548 PM CST SAT JAN 24 2015
RADAR SHOWS AN AREA OF LIGHT SNOW EXTENDING WEST OF BISMARCK.
BASED ON THIS AND LATEST HRRR RUNS WILL EXTEND THE LIKELY POPS FOR
SNOW WEST THROUGH MORTON COUNTY AND SOUTH TO THE SOUTH DAKOTA
BORDER. WILL LEAVE WIND ADVISORY GOING UNTIL 7 PM AS WINDS CONTINUE
TO GUST OVER 40 MPH AT SAND CREEK RAWS AND HETTINGER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
AN UPPER LEVEL WAVE CONTINUES TO GENERATE AN AREA OF PRECIPITATION
EXTENDING OVER CENTRAL NORTH DAKOTA. THIS ACTIVITY WILL CONTINUE
TO PIVOT EAST THROUGH TONIGHT. WIND ADVISORY CONDITIONS WILL
CONTINUE OVER SOUTHWESTERN NORTH DAKOTA THROUGH THE REMAINDER OF
THE AFTERNOON AS WELL. THE MAIN FORECAST CHALLENGE WILL BE
DETERMINING THE PRECIPITATION TYPE FOR THE NEXT FEW HOURS.
A COOL CANADIAN AIR MASS CONTINUES TO NOSE INTO NORTH CENTRAL NORTH
DAKOTA THIS AFTERNOON. THIS HAS RESULTED IN ALL SNOW BEING REPORTED
OVER NORTH CENTRAL NORTH DAKOTA. HOWEVER...RELATIVELY WARMER
BOUNDARY LAYER AIR IS GENERATING A NARROW PATCH OF FREEZING RAIN
PRIMARILY OVER JAMESTOWN. AS THE CANADIAN AIR MASS NOSES SOUTH...THE
PRECIP TYPE SHOULD CONTINUE TO TRANSITION FROM RAIN/FREEZING RAIN TO
ALL SNOW OVER THE JAMES RIVER VALLEY BY THIS EVENING.
SNOW WILL LIKELY CONTINUE EAST OF HIGHWAY 83 TONIGHT. BY SUNDAY
MORNING...STORM TOTAL SNOW AMOUNTS SHOULD RANGE BETWEEN 1 AND 2
INCHES ALONG AND EAST OF A LINE FROM MINOT TO STEELE TO ELLENDALE.
AREAS WEST OF SAID LINE SHOULD RECEIVE LESS THAN AN INCH OF NEW SNOW.
LOW PRESSURE MOVING ACROSS SASKATCHEWAN WILL GENERATE DRY AND WARM
SOUTHWESTERLY FLOW OVER WESTERN AND CENTRAL NORTH DAKOTA SUNDAY. DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES ARE FORECAST. SUNDAY
AFTERNOON HIGHS SHOULD RANGE FROM THE 30S EAST TO THE UPPER 40S
SOUTHWEST.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
...DRY WITH ABOVE NORMAL TEMPERATURES...
AN UPPER LEVEL RIDGE CURRENTLY OVER THE WEST COAST WILL SLOWLY
SHIFT EAST THROUGH THE NEXT COUPLE OF DAYS AND EVENTUALLY CENTER
ACROSS THE PLAINS TUESDAY. WITH PREDOMINATELY WEST WINDS THIS SETUP
WILL ALLOW FOR WELL ABOVE NORMAL TEMPERATURES THROUGH MIDWEEK.
ZONAL FLOW SHOULD THEN DEVELOP THURSDAY...WITH A TRANSITION TO
COOLER NORTHWEST FLOW BY THE WEEKEND. UPPER 40S ARE LIKELY ACROSS
MOST OF WESTERN AND CENTRAL NORTH DAKOTA MONDAY AND TUESDAY WITH
50S LIKELY ACROSS THE SOUTHWEST. BY THE WEEKEND ARCTIC AIR MAY
MAKE A RETURN TO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 548 PM CST SAT JAN 24 2015
FAST MOVING LOW PRESSURE ACROSS THE EASTERN DAKOTAS WILL MOVE
SOUTHEAST TONIGHT. AN EXTENSIVE AREA OF MVFR TO IFR WILL REMAIN
OVER THE STATE IN ITS WAKE. SNOW WITH OCCASIONAL IFR CONDITIONS WILL
PREVAIL FROM KMOT-KBIS-KJMS THROUGH 06Z THEN SLOWLY IMPROVE BUT
STRATUS AND MVFR WILL PERSIST THROUGH THE NIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...TM
LONG TERM...AJ
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
703 PM CST SAT JAN 24 2015
.UPDATE...
ISSUED AT 702 PM CST SAT JAN 24 2015
WIND ADVISORY HAS EXPIRED. EMPHASIZED THE EVENING LIGHT SNOW SOUTH
CENTRAL WITH DEFINITE POPS.
UPDATE ISSUED AT 548 PM CST SAT JAN 24 2015
RADAR SHOWS AN AREA OF LIGHT SNOW EXTENDING WEST OF BISMARCK.
BASED ON THIS AND LATEST HRRR RUNS WILL EXTEND THE LIKELY POPS FOR
SNOW WEST THROUGH MORTON COUNTY AND SOUTH TO THE SOUTH DAKOTA
BORDER. WILL LEAVE WIND ADVISORY GOING UNTIL 7 PM AS WINDS CONTINUE
TO GUST OVER 40 MPH AT SAND CREEK RAWS AND HETTINGER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
AN UPPER LEVEL WAVE CONTINUES TO GENERATE AN AREA OF PRECIPITATION
EXTENDING OVER CENTRAL NORTH DAKOTA. THIS ACTIVITY WILL CONTINUE
TO PIVOT EAST THROUGH TONIGHT. WIND ADVISORY CONDITIONS WILL
CONTINUE OVER SOUTHWESTERN NORTH DAKOTA THROUGH THE REMAINDER OF
THE AFTERNOON AS WELL. THE MAIN FORECAST CHALLENGE WILL BE
DETERMINING THE PRECIPITATION TYPE FOR THE NEXT FEW HOURS.
A COOL CANADIAN AIR MASS CONTINUES TO NOSE INTO NORTH CENTRAL NORTH
DAKOTA THIS AFTERNOON. THIS HAS RESULTED IN ALL SNOW BEING REPORTED
OVER NORTH CENTRAL NORTH DAKOTA. HOWEVER...RELATIVELY WARMER
BOUNDARY LAYER AIR IS GENERATING A NARROW PATCH OF FREEZING RAIN
PRIMARILY OVER JAMESTOWN. AS THE CANADIAN AIR MASS NOSES SOUTH...THE
PRECIP TYPE SHOULD CONTINUE TO TRANSITION FROM RAIN/FREEZING RAIN TO
ALL SNOW OVER THE JAMES RIVER VALLEY BY THIS EVENING.
SNOW WILL LIKELY CONTINUE EAST OF HIGHWAY 83 TONIGHT. BY SUNDAY
MORNING...STORM TOTAL SNOW AMOUNTS SHOULD RANGE BETWEEN 1 AND 2
INCHES ALONG AND EAST OF A LINE FROM MINOT TO STEELE TO ELLENDALE.
AREAS WEST OF SAID LINE SHOULD RECEIVE LESS THAN AN INCH OF NEW SNOW.
LOW PRESSURE MOVING ACROSS SASKATCHEWAN WILL GENERATE DRY AND WARM
SOUTHWESTERLY FLOW OVER WESTERN AND CENTRAL NORTH DAKOTA SUNDAY. DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES ARE FORECAST. SUNDAY
AFTERNOON HIGHS SHOULD RANGE FROM THE 30S EAST TO THE UPPER 40S
SOUTHWEST.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
...DRY WITH ABOVE NORMAL TEMPERATURES...
AN UPPER LEVEL RIDGE CURRENTLY OVER THE WEST COAST WILL SLOWLY
SHIFT EAST THROUGH THE NEXT COUPLE OF DAYS AND EVENTUALLY CENTER
ACROSS THE PLAINS TUESDAY. WITH PREDOMINATELY WEST WINDS THIS SETUP
WILL ALLOW FOR WELL ABOVE NORMAL TEMPERATURES THROUGH MIDWEEK.
ZONAL FLOW SHOULD THEN DEVELOP THURSDAY...WITH A TRANSITION TO
COOLER NORTHWEST FLOW BY THE WEEKEND. UPPER 40S ARE LIKELY ACROSS
MOST OF WESTERN AND CENTRAL NORTH DAKOTA MONDAY AND TUESDAY WITH
50S LIKELY ACROSS THE SOUTHWEST. BY THE WEEKEND ARCTIC AIR MAY
MAKE A RETURN TO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 548 PM CST SAT JAN 24 2015
FAST MOVING LOW PRESSURE ACROSS THE EASTERN DAKOTAS WILL MOVE
SOUTHEAST TONIGHT. AN EXTENSIVE AREA OF MVFR TO IFR WILL REMAIN
OVER THE STATE IN ITS WAKE. SNOW WITH OCCASIONAL IFR CONDITIONS WILL
PREVAIL FROM KMOT-KBIS-KJMS THROUGH 06Z THEN SLOWLY IMPROVE BUT
STRATUS AND MVFR WILL PERSIST THROUGH THE NIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...TM
LONG TERM...AJ
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
555 PM CST SAT JAN 24 2015
.UPDATE...
ISSUED AT 548 PM CST SAT JAN 24 2015
RADAR SHOWS AN AREA OF LIGHT SNOW EXTENDING WEST OF BISMARCK.
BASED ON THIS AND LATEST HRRR RUNS WILL EXTEND THE LIKELY POPS FOR
SNOW WEST THROUGH MORTON COUNTY AND SOUTH TO THE SOUTH DAKOTA
BORDER. WILL LEAVE WIND ADVISORY GOING UNTIL 7 PM AS WINDS CONTINUE
TO GUST OVER 40 MPH AT SAND CREEK RAWS AND HETTINGER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
AN UPPER LEVEL WAVE CONTINUES TO GENERATE AN AREA OF PRECIPITATION
EXTENDING OVER CENTRAL NORTH DAKOTA. THIS ACTIVITY WILL CONTINUE
TO PIVOT EAST THROUGH TONIGHT. WIND ADVISORY CONDITIONS WILL
CONTINUE OVER SOUTHWESTERN NORTH DAKOTA THROUGH THE REMAINDER OF
THE AFTERNOON AS WELL. THE MAIN FORECAST CHALLENGE WILL BE
DETERMINING THE PRECIPITATION TYPE FOR THE NEXT FEW HOURS.
A COOL CANADIAN AIR MASS CONTINUES TO NOSE INTO NORTH CENTRAL NORTH
DAKOTA THIS AFTERNOON. THIS HAS RESULTED IN ALL SNOW BEING REPORTED
OVER NORTH CENTRAL NORTH DAKOTA. HOWEVER...RELATIVELY WARMER
BOUNDARY LAYER AIR IS GENERATING A NARROW PATCH OF FREEZING RAIN
PRIMARILY OVER JAMESTOWN. AS THE CANADIAN AIR MASS NOSES SOUTH...THE
PRECIP TYPE SHOULD CONTINUE TO TRANSITION FROM RAIN/FREEZING RAIN TO
ALL SNOW OVER THE JAMES RIVER VALLEY BY THIS EVENING.
SNOW WILL LIKELY CONTINUE EAST OF HIGHWAY 83 TONIGHT. BY SUNDAY
MORNING...STORM TOTAL SNOW AMOUNTS SHOULD RANGE BETWEEN 1 AND 2
INCHES ALONG AND EAST OF A LINE FROM MINOT TO STEELE TO ELLENDALE.
AREAS WEST OF SAID LINE SHOULD RECEIVE LESS THAN AN INCH OF NEW SNOW.
LOW PRESSURE MOVING ACROSS SASKATCHEWAN WILL GENERATE DRY AND WARM
SOUTHWESTERLY FLOW OVER WESTERN AND CENTRAL NORTH DAKOTA SUNDAY. DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES ARE FORECAST. SUNDAY
AFTERNOON HIGHS SHOULD RANGE FROM THE 30S EAST TO THE UPPER 40S
SOUTHWEST.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
...DRY WITH ABOVE NORMAL TEMPERATURES...
AN UPPER LEVEL RIDGE CURRENTLY OVER THE WEST COAST WILL SLOWLY
SHIFT EAST THROUGH THE NEXT COUPLE OF DAYS AND EVENTUALLY CENTER
ACROSS THE PLAINS TUESDAY. WITH PREDOMINATELY WEST WINDS THIS SETUP
WILL ALLOW FOR WELL ABOVE NORMAL TEMPERATURES THROUGH MIDWEEK.
ZONAL FLOW SHOULD THEN DEVELOP THURSDAY...WITH A TRANSITION TO
COOLER NORTHWEST FLOW BY THE WEEKEND. UPPER 40S ARE LIKELY ACROSS
MOST OF WESTERN AND CENTRAL NORTH DAKOTA MONDAY AND TUESDAY WITH
50S LIKELY ACROSS THE SOUTHWEST. BY THE WEEKEND ARCTIC AIR MAY
MAKE A RETURN TO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 548 PM CST SAT JAN 24 2015
FAST MOVING LOW PRESSURE ACROSS THE EASTERN DAKOTAS WILL MOVE
SOUTHEAST TONIGHT. AN EXTENSIVE AREA OF MVFR TO IFR WILL REMAIN
OVER THE STATE IN ITS WAKE. SNOW WITH OCCASIONAL IFR CONDITIONS WILL
PREVAIL FROM KMOT-KBIS-KJMS THROUGH 06Z THEN SLOWLY IMPROVE BUT
STRATUS AND MVFR WILL PERSIST THROUGH THE NIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM MST THIS EVENING FOR NDZ031>033-040-041-
043-044.
&&
$$
UPDATE...WAA
SHORT TERM...TM
LONG TERM...AJ
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1245 AM CST FRI JAN 23 2015
.UPDATE...
ISSUED AT 1245 AM CST FRI JAN 23 2015
MID LEVEL S/WV TROUGH MOVING SOUTHEAST ACROSS FAR SOUTH CENTRAL
CANADA WITH ITS ASSOCIATED SFC TROUGH STRETCHED ACROSS
NORTHEASTERN ND SOUTHWEST THROUGH SOUTH CENTRAL NORTH DAKOTA.
ENHANCED FORCING NEAR THE MID LEVEL WAVE DEVELOPING PRECIPITATION
ACROSS THE NORTH CENTRAL AND EASTERN PARTS OF THE STATE EARLY THIS
MORNING...WITH THE HIGHER RADAR RETURNS FROM DEVILS LAKE TO GRAND
FORKS. AIR TEMPERATURES GENERALLY 34-39F WHERE RADAR RETURNS ARE.
HOWEVER...SURFACE/GROUND TEMPERATURES BELOW FREEZING SO ANY
PRECIPITATION THAT IS REACHING THE GROUND WILL FREEZE ON CONTACT.
WITH LACK OF DECENT REFLECTIVITIES OPTED TO HIGHLIGHT THE FREEZING
RAIN POSSIBILITY WITH A SPECIAL WEATHER STATEMENT FOR NOW.
PRECIPITATION WILL CONTINUE SOUTH AND SHOULD EXIT THE LOCAL AREA
BY 12Z.
MAIN UPDATES WERE TO POPS...EXPANDING THEM A BIT BUT LEFT AT
SLIGHT CHANCE...AND BUMPED TEMPS UP A TAD.
UPDATE ISSUED AT 957 PM CST THU JAN 22 2015
QUICK UPDATE FOR POPS BASED ON CURRENT RADAR...KEPT A LITTLE
HIGHER POPS NORTH CENTRAL THROUGH THE EVENING AND INTO THE EARLY
OVERNIGHT HOURS. LATEST RAP SHOWS PRECIP HOLDING ON THROUGH AROUND
06-07 UTC WHICH AGREES WITH CURRENT FORECAST. LATEST HRRR HOLDS
PRECIP TOGETHER A LITTLE LONGER AND DROPS IT FARTHER SOUTH. IF
THIS WOULD HOLD TRUE AND PRECIP DOES NOT EVAPORATE...WE COULD SEE
A FEW FREEZING SPRINKLES OR LIGHT FREEZING RAIN AS REFLECTIVITIES
DROP SOUTH TOWARD GARRISON...HARVEY AND CARRINGTON. THATS A BIG
IF...AND WOULD STILL BE TALKING ABOUT ONLY TRACE AMOUNTS. WILL
KEEP ANY ACCUMULATING PRECIP CONFINED TO THE NORTH CENTRAL FOR NOW
AND PASS ALONG TO THE OVERNIGHT SHIFT.
UPDATE ISSUED AT 842 PM CST THU JAN 22 2015
SHOWERS HAVE INTENSIFIED ACROSS SOUTHWEST MB INTO NORTH CENTRAL
NORTH DAKOTA THIS EVENING AND HAVE BUMPED UP POPS FROM AROUND
SHERWOOD EAST THROUGH BOTTINEAU AND THE TURTLE MOUNTAINS TO
BELCOURT. QUITE A BIT OF DRY AIR BELOW THE PRECIPITATION AND
QUICK MOVEMENT WILL LIKELY YIELD MAINLY TRACE AMOUNTS. A FEW AREAS
COULD SEE A HUNDREDTH OR TWO. WARM FRONT HAS PUSHED INTO NORTHEAST
NORTH DAKOTA THUS TEMPERATURES ARE MAINLY IN THE MID 30S...AND
SHOULD REMAIN STEADY WITH A MODERATE WEST TO SOUTHWEST SURFACE
FLOW. AT THIS TIME IT LOOKS LIKE MAINLY SPRINKLES/RAIN SHOWERS.
WITH A SMALL PROBABILITY OF SOME LIGHT FREEZING RAIN AROUND
MIDNIGHT...BEFORE PRECIP TAPERS OFF AND MOVES EAST.
UPDATE ISSUED AT 605 PM CST THU JAN 22 2015
NO SIGNIFICANT UPDATES TO THE EARLY EVENING FORECAST. SURFACE LOW
TRACKING EAST ACROSS SOUTHERN CANADA. VERY LIGHT PRECIPITATION
EXTENDING FROM BRANDON SOUTHWEST TO WEYBURN AND JUST CLIPPING THE
INTERNATIONAL BORDER FROM CROSBY TO SHERWOOD. CURRENT TEMPERATURES
ARE ABOVE FREEZING AND EXPECTED PRECIPITATION WILL BE MAINLY TRACE
AMOUNTS. AT THIS TIME NO SIGNIFICANT HAZARDS EXPECTED...BUT WILL
MAINTAIN A SLIGHT CHANCE OF A MIX OF RAIN...SNOW AND FREEZING RAIN
ACROSS THE FAR NORTH EARLY THIS EVENING AND THEN DROPPING
SOUTHEAST INTO THE JAMES RIVER VALLEY LATER TONIGHT. UPDATED TEXT
PRODUCTS OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 310 PM CST THU JAN 22 2015
CURRENT SURFACE ANALYSIS PLACES LOW PUSHING THROUGH NORTHERN
MANITOBA WITH HIGH OVER THE GREAT BASIN. UPPER LEVEL ANALYSIS
PLACES RIDGE OVER THE WESTERN CONUS WITH A WEAK SHORTWAVE MOVING
THROUGH SOUTHERN SASKATCHEWAN INTO CENTRAL MONTANA. A FEW LIGHT
SHOWERS HAVE DEVELOPED OVER SOUTHERN SASKATCHEWAN/MANITOBA WITH
THIS SYSTEM.
FOR TONIGHT...AFOREMENTIONED SHORT WAVE MOVES THROUGH THE AREA
WHICH WILL BRING PRECIPITATION CHANCES MAINLY TO NORTHERN INTO
CENTRAL NORTH DAKOTA...THOUGH THE WAVE IS QUITE WEAK SO WILL LEAVE
CHANCES ON THE LOW SIDE. SOUNDING ANALYSIS SUGGESTS MAINLY RAIN
WITH THIS SYSTEM...WHICH COULD LEAD TO SOME FREEZING RAIN IF IT IS
PRECIPITATING WHEN TEMPS DROP BELOW FREEZING. SKIES WILL START
CLEARING IN THE WAKE OF THE WAVE AS IT PASSES THROUGH LATE TONIGHT.
ON FRIDAY...QUIET WEATHER IS EXPECTED AS UPPER RIDGE TO THE WEST
CONTINUES TO BE THE DOMINATE FEATURE AND REGION IS BETWEEN SYSTEM.
TEMPERATURES WILL REMAIN QUITE MILD.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 352 PM CST THU JAN 22 2015
ABOVE NORMAL TEMPERATURES AND SLIGHT CHANCES RAIN...FREEZING RAIN
AND SNOW HIGHLIGHT THE EXTENDED FORECAST.
AN UPPER LEVEL RIDGE ACROSS THE WEST COAST WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK. THIS WILL KEEP THE MAJORITY OF THE ARCTIC
AIR BOTTLED UP AROUND THE HUDSON BAY. FOR OUR AREA TEMPERATURES
WILL GENERALLY RANGE FROM THE 30S ACROSS THE EASTERN JAMES VALLEY
AND UPPER 40S ACROSS WESTERN NORTH DAKOTA. TEMPERATURES IN THE 50S
ARE POSSIBLE EARLY NEXT WEEK.
SEVERAL WEAK CLIPPERS WILL SWING THROUGH THE AREA DURING THE
EXTENDED PERIOD. THE FIRST SUCH CLIPPER IS EXPECTED TO AFFECT THE
AREA SATURDAY INTO SUNDAY...WITH THE OTHER TWO ARRIVING MONDAY AND
THURSDAY.
FOR SATURDAY INTO SUNDAY...LATEST GUIDANCE SEEMS TO HAVE TAKEN A STEP
BACKWARD AS FAR AS CONSISTENCY AND AGREEMENT ARE CONCERNED. THE 12
UTC ECMWF IS MORE PROGRESSIVE AND BULLISH WITH QPF AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. WHEREAS THE GFS AND SREF ARE
SLOWER AND MAINLY DRY. THE NAM INITIALLY KEEPS PRECIP OUT OF THE
AREA AS THE CLIPPER SLIDES ACROSS EASTERN NORTH DAKOTA...BUT THEN
BRINGS SOME WRAP-AROUND PRECIP INTO WESTERN NORTH DAKOTA. DUE TO
THE WIDE RANGE OF MODEL SOLUTIONS CONFIDENCE ON ANY PARTICULAR
SCENARIO IS RATHER LOW. THEREFORE...KEPT PRECIP CHANCES BELOW 25
PERCENT THROUGH SUNDAY. LOOKING AT FORECAST SOUNDING PROFILES IT
WOULD APPEAR THAT THE MOST FAVORED PRECIP TYPE (IF PRECIPITATION
DOES IN FACT FORM) WOULD BE RAIN ACROSS THE MAJORITY OF THE AREA.
WITH COOLER TEMPERATURES ALOFT AND AT THE SURFACE FURTHER EAST...A
MIX OF FREEZING DRIZZLE OR SNOW FLURRIES ARE POSSIBLE ALONG AND
EAST OF HWY 281. WITH QPF AMOUNTS EXPECTED TO BE LIGHT...OR
POTENTIALLY NONEXISTENT DEPENDING ON WHAT GUIDANCE YOU
BELIEVE...IMPACTS SHOULD BE MINIMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1245 AM CST FRI JAN 23 2015
A BAND OF LIGHT PRECIPITATION FROM NEAR MINOT TO GRAND FORKS WILL
DROP SOUTHEAST TONIGHT. AIR TEMPERATURES ARE IN THE MID 30S TO
AROUND 40 DEGREES UNTIL PRECIPITATION PASSES...AND PRECIPITATION IS
VERY LIGHT SO JUST MENTIONED A VCSH AT KMOT THROUGH 09 UTC AND AT
KJMS FROM 07-10 UTC WITH A VFR CEILING AROUND 9000 FEET. OTHERWISE
VFR MID AND HIGH LEVEL CLOUDS THROUGH THE FORECAST PERIOD WITH A
MODERATE WEST TO NORTHWEST FLOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JJS
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
955 PM EST SAT JAN 24 2015
.SYNOPSIS...
A CLIPPER SYSTEM WILL TRACK ACROSS THE REGION SUNDAY INTO SUNDAY
NIGHT...BRINGING ACCUMULATING SNOW ALONG AND NORTH OF INTERSTATE 70.
COLDER WEATHER WILL MOVE IN BEHIND THIS SYSTEM FOR THE BEGINNING
OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDATE FOCUSED MAINLY IN THE CLOUD COVER THIS EVENING, AREAS IN
THE S AND W HAVE BROKEN OUT OF THE LOW CLOUDS FOR A FEW
HOURS...BUT LATEST SATELLITE LOOP SHOWS MID CLOUDS WORKING E
TOWARDS THE AREA...SO SKY SHOULD GO MOSTLY CLOUDY BY MIDNIGHT OR
SHORTLY AFTERWARDS. HAVE CLOUDY SKIES FOR THE NORTH AND
INCREASING CLOUDS IN THE SOUTH.
00Z NAM HAS TRICKLED IN ALONG WITH SOME RAP AND HRRR AND THEY HAVE
TRENDED A LITTLE SLOWER WITH THE ONSET OF THE PCPN TOMORROW. SO
BACKED OFF ON THE PCPN AT THE END OF THE TONIGHT PERIOD.
PREVIOUS LOWS IN THE LOWER 30S STILL LOOK GOOD.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
TRICKY SNOW FORECAST WITH SOME DIGGING OF THE CLIPPER SYSTEM AS IT
ENTERS THE REGION ON SUNDAY...WITH THE ONLY LOCATION TO REMAIN
PREDOMINATELY SNOW BEING THE FAR NW. THE S/WV STILL SHOWING SIGNS
OF AMPLIFICATION AS IT DIGS SOUTH INTO FCST AREA. PRECIP IN MOST
LOCATIONS WILL BEGIN AS RAIN ON SUNDAY MORNING.
HAVE SLOWED ONSET SLIGHTLY...AND DUE TO THE WARM AIR ADVECTION
AND LINGERING PERIOD OF RAIN OR RAIN/SNOW IN ESPECIALLY CENTRAL
OHIO...BEGAN SNOW ADVISORY AT 15Z/10AM. MOST LOCATIONS IN ADVISORY
WILL SEE 3-5 INCHES WITH SOME 6 INCH AMOUNTS...BUT THE TRICK IS IN
THE SURFACE/LOW LEVEL TEMPERATURES.
MODELS ARE SLOWLY PICKING UP ON THE STRENGTH OF THE SYSTEM...AS
WELL AS GFS/ECMWF CONVERGING ON TRACK...WITH NAM WARMER AND SLOWER
WITH A MORE NORTHERLY TRACK. LOOKING AT MODEL SOUNDINGS FOR
KDAY/KILN...CHANGEOVER TO ALL SNOW LIKELY NOT TO OCCUR UNTIL AFTER
7PM SUNDAY...WHICH IS BEHIND THE HEAVIEST PRECIPITATION POTENTIAL.
GREATEST UNCERTAINTY WILL BE IN THE AREA JUST SOUTH OF THE
ADVISORY...WHERE LOW LEVEL THERMAL PROFILES ARE VERY CLOSE TO
FREEZING. EARLIER COLD AIR INTRUSION WILL RESULT IN MORE SNOW
HERE...ALONG WITH HIGHER SNOW TO LIQUID RATIOS. HAVE GENERALLY
GONE WITH SNOW AT ONSET TO BE A 10:1 RATIO...THEN AS THE COLD AIR
DIGS INTO ESPECIALLY THE UPPER GREAT MIAMI VALLEY AND ST. MARYS
BASIN...RATIOS MORE IN THE 14:1 WITH THE COLDER AIR.
HAVE CONTINUED HOURLY TEMPERATURE TACTIC OF A BLEND OF MODEL 2M
TEMPERATURES DURING THE EVENT...AND THEN BELOW MODEL GUIDANCE FOR
SUNDAY NIGHT.
MONDAY HAS THE SYSTEM RETREATING WITH JUST LINGERING SNOW SHOWERS
IN THE EASTERN FCST AREA YIELDING LESS THAN AN INCH OF SNOW TOTAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A WEAK S/WV WILL DROP SOUTHEAST INTO THE REGION MONDAY NIGHT INTO
TUESDAY. MODELS DIFFER WITH ITS PLACEMENT. THE ECMWF IS FARTHER WEST
WHILE THE NAM/GFS ARE FARTHER EAST. HAVE GONE WITH THE LATTER WHICH
KEEPS CONTINUITY. THIS CALLS FOR A CHANCE OF LIGHT SNOW.
HIGH PRESSURE WILL BRIEFLY BUILD INTO THE AREA TUESDAY NIGHT INTO
WEDNESDAY. COLD TEMPERATURES ON TUESDAY WILL MODIFY SOME BY
WEDNESDAY.
FOR THE PERIOD WEDNESDAY NIGHT INTO THURSDAY NIGHT...MODELS ARE IN
FAIRLY DECENT AGREEMENT WITH THE TIMING OF UPCOMING WEATHER SYSTEMS.
A LEAD S/WV FOLLOWED BY A STRONG S/WV WILL MOVE THROUGH THE REGION
DURING THIS TIME FRAME. THIS WILL BE REFLECTED AT THE SURFACE BY LOW
PRESSURE AND A COLD FRONT. PCPN SHOULD ENCROACH THE WEST LATE
WEDNESDAY NIGHT AND SPREAD EAST ON THURSDAY. HOW FAST TEMPERATURES
WARM AHEAD OF THE FRONT BY PCPN ONSET WILL DETERMINE PCPN TYPE.
ALTHOUGH IT IS LOOKING LIKE A GOOD PART OF THE AREA WILL SEE SOME
SLEET/FREEZING RAIN AT THE ONSET...HAVE GONE WITH RAIN/SNOW MIX ATTM
GIVEN HOW FAR OUT IN THE EXTENDED THIS SYSTEM IS (GIVEN THAT IT IS
DIFFICULT TO PINPOINT MIXED PCPN TYPE THIS FAR OUT). THE ENTIRE
REGION WILL LIKELY GO OVER TO ALL RAIN FOR A TIME THURSDAY AFTN
AHEAD OF THE FRONT. IN THE WAKE OF THE SYSTEM THURSDAY NIGHT...WE
SHOULD SEE PCPN MIX WITH THEN CHANGE OVER TO A BRIEF PERIOD OF SNOW
BEFORE ENDING.
FOR FRIDAY INTO FRIDAY NIGHT...HIGH PRESSURE WILL ONCE AGAIN BUILD
INTO THE REGION. TEMPERATURES WILL COOL BACK DOWN TO BELOW SEASONAL
NORMALS.
LONG RANGE MODELS DISAGREE ON HOW FAST A MAJOR WEATHER PATTERN
CHANGE WILL OCCUR OVER THE WEEKEND INTO NEXT WEEK AS MUCH COLDER
ARCTIC AIR PLUNGES SOUTHEAST INTO THE GREAT LAKES AND THE OHIO
VALLEY. HAVE SIDED WITH THE ECMWF ATTM WHICH IS FASTER AND PUSHES AN
ARCTIC FRONT INTO THE REGION DURING THE SATURDAY/SUNDAY TIME FRAME.
WILL FORECAST A CHANCE OF SNOW WITH THIS SYSTEM.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
SERIES OF MVFR DECK CONTINUE TO DROP SE ACROSS THE REGION.
CVG/LUK/ILN HAVE CURRENTLY SCATTERED OUT...BUT CLOUDS IN CENTRAL
INDIANA AREA HEADING BACK IN. IT WILL BE CLOSE IF CVG/LUK SEE MVFR
CIGS LATER THIS EVENING. SATELLITE LOOP LOOKS LIKE THEY WILL WORK
IN FOR A COUPLE OF HOURS BEFORE SCATTERING BACK OUT. FOR THE NRN
TAFS MVFR CIGS SHOULD LINGER ALL NIGHT LONG.
AFT 12Z SUNDAY...THE SRN TAFS WILL SEE LOWERING CIGS AHEAD OF
APPROACHING STORM SYSTEM...REACHING MVFR CONDITIONS BETWEEN
16-18Z. NRN TAFS WHICH WILL HAVE LINGERING MVFR CIGS WILL SEE THEM
FALL TOWARD IFR AS PCPN WORKS IN AROUND 15Z. ANY PCPN SHOULD FALL
AS RAIN AT ALL THE TAFS THRU 21Z.
RAIN WILL CHANGE TO SNOW AT DAY/CMH-LCK AROUND 21Z...DROPPING CIGS
AND VSBYS. THE SRN TAFS PROBABLY WONT SEE THE CHANGE OVER TO SNOW
UNTIL AFT 00Z.
OUTLOOK...MVFR/IFR CIGS AND VSBYS LIKELY SUNDAY NIGHT. MVFR
CIGS WILL LIKELY PERSIST INTO MONDAY. MVFR CIGS AND VSBYS POSSIBLE
AGAIN TUESDAY THEN THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY FROM 10 AM SUNDAY TO 7 AM EST MONDAY
FOR OHZ026-034-035-042>046-051>056.
KY...NONE.
IN...WINTER WEATHER ADVISORY FROM 10 AM SUNDAY TO 7 AM EST MONDAY
FOR INZ050.
&&
$$
SYNOPSIS...JDR
NEAR TERM...SITES
SHORT TERM...JDR
LONG TERM...HICKMAN
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
852 AM EST FRI JAN 23 2015
.SYNOPSIS...
STRENGTHENING LOW PRESSURE ACROSS SOUTHEAST TODAY AND OFF NEW
ENGLAND COAST SATURDAY. CLIPPER LATE SUNDAY/SUNDAY NIGHT. TURNING
COLDER MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
850 AM UPDATE...TWEAKED POPS A BIT...TO INCLUDE A CHANCE ACROSS
THE SOUTH A COUPLE OF HOURS QUICKER BASED ON RADAR TRENDS.
OTHERWISE...NO SIGNIFICANT CHANGES NEEDED AT THIS POINT.
PREVIOUS DISCUSSION BELOW...
ALL ON EYES ON SURFACE LOW TRAVERSING THRU THE SE STATES
TODAY...FOLLOWED BY AN UPPER TROF AXIS CROSSING THE REGION
OVERNIGHT. THERE ARE A NUMBER OF MITIGATING FACTORS THAT WILL KEEP
THE WINTRY EFFECTS FROM THIS MINIMAL. A LACK OF A SURFACE HIGH TO
THE N...MARGINAL COLD AIR ALOFT...AND A PESKY INVERTED SURFACE TROF
OVER THE AREA...ALL POINT TO MORE OF A NUISANCE EVENT.
AS FOR THE NITTY GRITTY DETAILS...
SPED UP POPS A BIT FROM PREVIOUS FORECAST...PRIMARILY USING THE HRRR
TIMING. A RELATIVELY DEEP DOWNSLOPING SSE TO SE FLOW INTO MIDDAY MAY
GIVE TEMPS A SPIKE. HOWEVER...NONE OF THE MODELS ARE SHOWING THIS
EXCEPT HRRR AND RUC. SO KEPT HIGHS IN CHECK BUT STILL A FEW DEGREES
ABOVE GUIDANCE FROM ALONG US119 AND I79 CORRIDOR OVER TO W SLOPES.
THERMAL PROFILES FROM VARIOUS HI RES MODELS INDICATED PRECIP
STARTING AS RAIN OUTSIDE OF THE MOUNTAINS. PRECIP SHOULD START OUT
AS SNOW OR A MIX OF SNOW AND SLEET IN THE MOUNTAINS...WHERE A FEW
INCHES WERE CODED UP FOR LATE THIS AFTERNOON.
THIS EVENING...THE STEADY PRECIP WILL HAVE SHIFTED INTO SE OH AND N
WV WITH SCT COVERAGE IN THE MID LEVEL DRY PUNCH ELSEWHERE. THE
SURFACE LOW WILL BE MAKING A RUN OFF THE TIDEWATER REGION WITH THE
INVERTED SURFACE TROF LINGERING OVER THE AREA. MODEL SOUNDINGS SHOW
A WARM LAYER ALOFT ACROSS THE MOUNTAINS...DEEP ENOUGH FOR THE PRECIP
TO CHANGE TO FREEZING RAIN ACROSS THE ELEVATION ABOVE 3.5KFT...WITH
SOME SLEET EXPECTED OVER THE TYGART AND ESPECIALLY THE GREENBRIER
VALLEY. IT IS EVEN POSSIBLE SNOWSHOE CHANGES TO LIGHT RAIN FOR A
TIME. MEANWHILE...THE CHANGEOVER TO WET SNOW WILL BE OCCURRING
ACROSS NE KY AND SE OH AS THE UPPER TROF AXIS CLOSES IN WITH COOLING
ALOFT. THERE CONTINUES TO BE A DEFORMATION BAND OF SORTS SHOWING UP
ON THE MODELS AS THE UPPER TROF CROSSES. HAVE ORIENTED THE POPS TO
REFLECT THIS THINKING...SLOWLY TRACKING IT E FROM SE OH/NE KY INTO C
WV BY PREDAWN HRS. THIS SHOULD COINCIDE WITH THE CHANGEOVER TO WET
SNOW. HAVE ALLOWED AROUND AN INCH TO FALL ACROSS SE OH/NE KY/W WV
WITH A COATING FURTHER E AS THE OVERALL BAND BEGINS TO WEAKEN.
ACROSS THE MOUNTAINS...PRECIP WILL CHANGE BACK TO SNOW AFTER
MIDNIGHT BUT PRECIP SHOULD BE SPOTTY UNTIL THE UPPER TROF AXIS AND
DEFORMATION BAND MOVES IN TOWARD MORNING.
AFTER COLLABORATION WITH SURROUNDING OFFICES...HAVE HOISTED A WINTER
WEATHER ADVISORY FOR RANDOLPH AND POCAHONTAS. DESPITE NOT REACHING
CRITERIA SNOW WISE...THERE IS EXPECTED TO BE SOME FREEZING RAIN IN
THE HIGHER ELEVATIONS WHICH MAY ACCRUE TO AROUND A TENTH OF AN
INCH. STARTED IT THIS AFTERNOON TO HIT THE INITIAL LIGHT
ACCUMULATION OF SNOW WITH THE ICE THREAT FROM 00 TO 06Z. ENDED IT AT
15Z WHEN THE UPPER TROF IS EXPECTED TO HAVE MOVED THRU.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
MODELS SHOW SYSTEM PULLING OUT EARLY SATURDAY. SOME MARGINAL UPSLOPE
THEN APPEARS POSSIBLE SATURDAY NIGHT AS NORTHWEST WINDS PULL IN SOME
COOLER AIR. 850 MB TEMPERATURES ARE MARGINAL FOR AUTO CONVECTION IN
THE LOWER LEVELS...SO WILL KEEP POPS IN THE CHANCE CATEGORY.
MODELS ARE A BIT FASTER WITH A CLIPPER MOVING THROUGH LATE
SUNDAY/SUNDAY EVENING. BOTH NAM AND GFS ARE SHOWING LOTS OF LIFT
WELL SOUTH OF THE LOW TRACK...BUT CLIPPERS USUALLY STRUGGLE TO
PRODUCE PRECIPITATION SOUTH OF THE LOW. THEREFORE...WILL SHOW A
NORTH SOUTH GRADIENT OF POPS.
COLDER AIR BEHIND THE CLIPPER ON MONDAY IS COLD ENOUGH FOR AUTO
CONVECTIVE CONDITIONS IN THE LOWER LEVELS...SO WILL KEEP HIGH POPS
OF SNOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE TREND THAT WE MENTIONED YESTERDAY REMAINS...THE CLIPPER COMING
EAST THROUGH THE MIDWEST INTO THE UPPER OHIO VALLEY...AT A HIGHER
LATITUDE REMAINS. AS A RESULT...WAS A BIT SLOWER BRINGING IN THE
COLDER AIR LATE SUNDAY NIGHT INTO MONDAY. POPS INCREASE NW TO SE
DURING SUNDAY NIGHT IN THE WAKE OF THE CLIPPER PASSING OUR LONGITUDE.
WE WILL BE CONSISTENT WITH POPS IN THE LIKELY CATEGORY MONDAY INTO
MONDAY EVENING BEFORE WANING FROM WEST TO EAST. AS MOISTURE
THINS...850 TEMPS BECOME COLDER...SO HELD ONTO SOME FLAKES EVEN
INTO TUESDAY EAST OF THE OHIO RIVER.
STILL DRY ON WEDNESDAY. WARMING 850 TEMPS WEDNESDAY NIGHT INTO
THURSDAY. NEXT WESTERN FRONT LONG ABOUT THURSDAY AFTERNOON.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
12Z FRIDAY THRU 12Z SATURDAY...
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH SOUTHWEST TODAY.
CIGS WILL LOWER AS PRECIP MOVES IN FROM THE SW THIS
AFTERNOON...FIRST ACROSS SW VA AND SE WV AFFECTING KBKW BY 18Z
WITH MVFR. PRECIPITATION OVERSPREADS THE REGION TOWARD EVENING
WITH MOST OF REMAINING TERMINALS EXPERIENCING MVFR CIGS IN PRECIP
BY 21Z. MVFR VSBY WILL LAG BEHIND A FEW HRS. EXPECT BULK OF PRECIP
THRU 00Z TO BE LIQUID...SAVE FOR A HR OR TWO OF A MIX FOR KBKW AT
ONSET.
CIGS WILL LOWER INTO IFR LATE THIS AFTERNOON AND EARLY EVENING WITH A
GRADUAL CHANGEOVER TO WET SNOW OVERNIGHT. VSBY WILL FOLLOW SUITE WITH
LOCALIZED VLIFR VSBY. IN THE HIGH TERRAIN A VARIETY OF PRECIP
TYPES CAN BE EXPECTED DEPENDING ON ELEVATION.
LOW LEVEL FLOW WILL BRIEFLY STRENGTHEN OUT OF SSE THIS
MORNING...PROVIDING FOR SOME 15 TO 20 KT GUSTS AT KBKW. OTHERWISE 5
TO 10 KT WINDS OUT OF NE FOR W TERMINALS AND E FOR THE MOUNTAIN
TERMINALS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING LOWERING OF CIGS INTO MVFR OR WORSE
ALONG WITH VSBY MAY VARY A FEW HRS THIS AFTERNOON/EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY H H H H H M M M M M M M
HTS CONSISTENCY H H H H H M M M M M H H
BKW CONSISTENCY H H M L H H H H H H H H
EKN CONSISTENCY H H H H H M H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H M H H M H M
AFTER 12Z SATURDAY...
IFR POSSIBLE EARLY SATURDAY MORNING IN SNOW. IFR POSSIBLE IN SNOW IN
THE HIGHER ELEVATIONS OF THE MOUNTAINS SUNDAY/SUNDAY NIGHT. IFR
POSSIBLE AREA WIDE IN SNOW SHOWERS MONDAY/MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 10 AM EST
SATURDAY FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/RPY/30
NEAR TERM...SL/30
SHORT TERM...RPY
LONG TERM...KTB
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
600 AM EST FRI JAN 23 2015
.SYNOPSIS...
STRENGTHENING LOW PRESSURE ACROSS SOUTHEAST TODAY AND OFF NEW
ENGLAND COAST SATURDAY. CLIPPER LATE SUNDAY/SUNDAY NIGHT. TURNING
COLDER MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE...
NO SIGNIFICANT CHANGES ATTM. DEFORMATION BAND TONIGHT MAY NEED TO
INITIALLY BE MOVED W A BIT IF HI RES MODEL TRENDS CONTINUE.
PREVIOUS DISCUSSION BELOW...
ALL ON EYES ON SURFACE LOW TRAVERSING THRU THE SE STATES
TODAY...FOLLOWED BY AN UPPER TROF AXIS CROSSING THE REGION
OVERNIGHT. THERE ARE A NUMBER OF MITIGATING FACTORS THAT WILL KEEP
THE WINTRY EFFECTS FROM THIS MINIMAL. A LACK OF A SURFACE HIGH TO
THE N...MARGINAL COLD AIR ALOFT...AND A PESKY INVERTED SURFACE TROF
OVER THE AREA...ALL POINT TO MORE OF A NUISANCE EVENT.
AS FOR THE NITTY GRITTY DETAILS...
SPED UP POPS A BIT FROM PREVIOUS FORECAST...PRIMARILY USING THE HRRR
TIMING. A RELATIVELY DEEP DOWNSLOPING SSE TO SE FLOW INTO MIDDAY MAY
GIVE TEMPS A SPIKE. HOWEVER...NONE OF THE MODELS ARE SHOWING THIS
EXCEPT HRRR AND RUC. SO KEPT HIGHS IN CHECK BUT STILL A FEW DEGREES
ABOVE GUIDANCE FROM ALONG US119 AND I79 CORRIDOR OVER TO W SLOPES.
THERMAL PROFILES FROM VARIOUS HI RES MODELS INDICATED PRECIP
STARTING AS RAIN OUTSIDE OF THE MOUNTAINS. PRECIP SHOULD START OUT
AS SNOW OR A MIX OF SNOW AND SLEET IN THE MOUNTAINS...WHERE A FEW
INCHES WERE CODED UP FOR LATE THIS AFTERNOON.
THIS EVENING...THE STEADY PRECIP WILL HAVE SHIFTED INTO SE OH AND N
WV WITH SCT COVERAGE IN THE MID LEVEL DRY PUNCH ELSEWHERE. THE
SURFACE LOW WILL BE MAKING A RUN OFF THE TIDEWATER REGION WITH THE
INVERTED SURFACE TROF LINGERING OVER THE AREA. MODEL SOUNDINGS SHOW
A WARM LAYER ALOFT ACROSS THE MOUNTAINS...DEEP ENOUGH FOR THE PRECIP
TO CHANGE TO FREEZING RAIN ACROSS THE ELEVATION ABOVE 3.5KFT...WITH
SOME SLEET EXPECTED OVER THE TYGART AND ESPECIALLY THE GREENBRIER
VALLEY. IT IS EVEN POSSIBLE SNOWSHOE CHANGES TO LIGHT RAIN FOR A
TIME. MEANWHILE...THE CHANGEOVER TO WET SNOW WILL BE OCCURRING
ACROSS NE KY AND SE OH AS THE UPPER TROF AXIS CLOSES IN WITH COOLING
ALOFT. THERE CONTINUES TO BE A DEFORMATION BAND OF SORTS SHOWING UP
ON THE MODELS AS THE UPPER TROF CROSSES. HAVE ORIENTED THE POPS TO
REFLECT THIS THINKING...SLOWLY TRACKING IT E FROM SE OH/NE KY INTO C
WV BY PREDAWN HRS. THIS SHOULD COINCIDE WITH THE CHANGEOVER TO WET
SNOW. HAVE ALLOWED AROUND AN INCH TO FALL ACROSS SE OH/NE KY/W WV
WITH A COATING FURTHER E AS THE OVERALL BAND BEGINS TO WEAKEN.
ACROSS THE MOUNTAINS...PRECIP WILL CHANGE BACK TO SNOW AFTER
MIDNIGHT BUT PRECIP SHOULD BE SPOTTY UNTIL THE UPPER TROF AXIS AND
DEFORMATION BAND MOVES IN TOWARD MORNING.
AFTER COLLABORATION WITH SURROUNDING OFFICES...HAVE HOISTED A WINTER
WEATHER ADVISORY FOR RANDOLPH AND POCAHONTAS. DESPITE NOT REACHING
CRITERIA SNOW WISE...THERE IS EXPECTED TO BE SOME FREEZING RAIN IN
THE HIGHER ELEVATIONS WHICH MAY ACCRUE TO AROUND A TENTH OF AN
INCH. STARTED IT THIS AFTERNOON TO HIT THE INITIAL LIGHT
ACCUMULATION OF SNOW WITH THE ICE THREAT FROM 00 TO 06Z. ENDED IT AT
15Z WHEN THE UPPER TROF IS EXPECTED TO HAVE MOVED THRU.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
MODELS SHOW SYSTEM PULLING OUT EARLY SATURDAY. SOME MARGINAL UPSLOPE
THEN APPEARS POSSIBLE SATURDAY NIGHT AS NORTHWEST WINDS PULL IN SOME
COOLER AIR. 850 MB TEMPERATURES ARE MARGINAL FOR AUTO CONVECTION IN
THE LOWER LEVELS...SO WILL KEEP POPS IN THE CHANCE CATEGORY.
MODELS ARE A BIT FASTER WITH A CLIPPER MOVING THROUGH LATE
SUNDAY/SUNDAY EVENING. BOTH NAM AND GFS ARE SHOWING LOTS OF LIFT
WELL SOUTH OF THE LOW TRACK...BUT CLIPPERS USUALLY STRUGGLE TO
PRODUCE PRECIPITATION SOUTH OF THE LOW. THEREFORE...WILL SHOW A
NORTH SOUTH GRADIENT OF POPS.
COLDER AIR BEHIND THE CLIPPER ON MONDAY IS COLD ENOUGH FOR AUTO
CONVECTIVE CONDITIONS IN THE LOWER LEVELS...SO WILL KEEP HIGH POPS
OF SNOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE TREND THAT WE MENTIONED YESTERDAY REMAINS...THE CLIPPER COMING
EAST THROUGH THE MIDWEST INTO THE UPPER OHIO VALLEY...AT A HIGHER
LATITUDE REMAINS. AS A RESULT...WAS A BIT SLOWER BRINGING IN THE
COLDER AIR LATE SUNDAY NIGHT INTO MONDAY. POPS INCREASE NW TO SE
DURING SUNDAY NIGHT IN THE WAKE OF THE CLIPPER PASSING OUR LONGITUDE.
WE WILL BE CONSISTENT WITH POPS IN THE LIKELY CATEGORY MONDAY INTO
MONDAY EVENING BEFORE WANING FROM WEST TO EAST. AS MOISTURE
THINS...850 TEMPS BECOME COLDER...SO HELD ONTO SOME FLAKES EVEN
INTO TUESDAY EAST OF THE OHIO RIVER.
STILL DRY ON WEDNESDAY. WARMING 850 TEMPS WEDNESDAY NIGHT INTO
THURSDAY. NEXT WESTERN FRONT LONG ABOUT THURSDAY AFTERNOON.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
12Z FRIDAY THRU 12Z SATURDAY...
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH SOUTHWEST TODAY.
CIGS WILL LOWER AS PRECIP MOVES IN FROM THE SW THIS
AFTERNOON...FIRST ACROSS SW VA AND SE WV AFFECTING KBKW BY 18Z
WITH MVFR. PRECIPITATION OVERSPREADS THE REGION TOWARD EVENING
WITH MOST OF REMAINING TERMINALS EXPERIENCING MVFR CIGS IN PRECIP
BY 21Z. MVFR VSBY WILL LAG BEHIND A FEW HRS. EXPECT BULK OF PRECIP
THRU 00Z TO BE LIQUID...SAVE FOR A HR OR TWO OF A MIX FOR KBKW AT
ONSET.
CIGS WILL LOWER INTO IFR LATE THIS AFTERNOON AND EARLY EVENING WITH A
GRADUAL CHANGEOVER TO WET SNOW OVERNIGHT. VSBY WILL FOLLOW SUITE WITH
LOCALIZED VLIFR VSBY. IN THE HIGH TERRAIN A VARIETY OF PRECIP
TYPES CAN BE EXPECTED DEPENDING ON ELEVATION.
LOW LEVEL FLOW WILL BRIEFLY STRENGTHEN OUT OF SSE THIS
MORNING...PROVIDING FOR SOME 15 TO 20 KT GUSTS AT KBKW. OTHERWISE 5
TO 10 KT WINDS OUT OF NE FOR W TERMINALS AND E FOR THE MOUNTAIN
TERMINALS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING LOWERING OF CIGS INTO MVFR OR WORSE
ALONG WITH VSBY MAY VARY A FEW HRS THIS AFTERNOON/EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H H H H H M M H M
HTS CONSISTENCY H H H H H H H H H M H M
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H M H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z SATURDAY...
IFR POSSIBLE EARLY SATURDAY MORNING IN SNOW. IFR POSSIBLE IN SNOW IN
THE HIGHER ELEVATIONS OF THE MOUNTAINS SUNDAY/SUNDAY NIGHT. IFR
POSSIBLE AREA WIDE IN SNOW SHOWERS MONDAY/MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 10 AM EST
SATURDAY FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...KTB
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
327 AM EST FRI JAN 23 2015
.SYNOPSIS...
STRENGTHENING LOW PRESSURE ACROSS SOUTHEAST TODAY AND OFF NEW
ENGLAND COAST SATURDAY. CLIPPER LATE SUNDAY/SUNDAY NIGHT. TURNING
COLDER MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ALL ON EYES ON SURFACE LOW TRAVERSING THRU THE SE STATES
TODAY...FOLLOWED BY AN UPPER TROF AXIS CROSSING THE REGION
OVERNIGHT. THERE ARE A NUMBER OF MITIGATING FACTORS THAT WILL KEEP
THE WINTRY EFFECTS FROM THIS MINIMAL. A LACK OF A SURFACE HIGH TO
THE N...MARGINAL COLD AIR ALOFT...AND A PESKY INVERTED SURFACE TROF
OVER THE AREA...ALL POINT TO MORE OF A NUISANCE EVENT.
AS FOR THE NITTY GRITTY DETAILS...
SPED UP POPS A BIT FROM PREVIOUS FORECAST...PRIMARILY USING THE HRRR
TIMING. A RELATIVELY DEEP DOWNSLOPING SSE TO SE FLOW INTO MIDDAY MAY
GIVE TEMPS A SPIKE. HOWEVER...NONE OF THE MODELS ARE SHOWING THIS
EXCEPT HRRR AND RUC. SO KEPT HIGHS IN CHECK BUT STILL A FEW DEGREES
ABOVE GUIDANCE FROM ALONG US119 AND I79 CORRIDOR OVER TO W SLOPES.
THERMAL PROFILES FROM VARIOUS HI RES MODELS INDICATED PRECIP
STARTING AS RAIN OUTSIDE OF THE MOUNTAINS. PRECIP SHOULD START OUT
AS SNOW OR A MIX OF SNOW AND SLEET IN THE MOUNTAINS...WHERE A FEW
INCHES WERE CODED UP FOR LATE THIS AFTERNOON.
THIS EVENING...THE STEADY PRECIP WILL HAVE SHIFTED INTO SE OH AND N
WV WITH SCT COVERAGE IN THE MID LEVEL DRY PUNCH ELSEWHERE. THE
SURFACE LOW WILL BE MAKING A RUN OFF THE TIDEWATER REGION WITH THE
INVERTED SURFACE TROF LINGERING OVER THE AREA. MODEL SOUNDINGS SHOW
A WARM LAYER ALOFT ACROSS THE MOUNTAINS...DEEP ENOUGH FOR THE PRECIP
TO CHANGE TO FREEZING RAIN ACROSS THE ELEVATION ABOVE 3.5KFT...WITH
SOME SLEET EXPECTED OVER THE TYGART AND ESPECIALLY THE GREENBRIER
VALLEY. IT IS EVEN POSSIBLE SNOWSHOE CHANGES TO LIGHT RAIN FOR A
TIME. MEANWHILE...THE CHANGEOVER TO WET SNOW WILL BE OCCURRING
ACROSS NE KY AND SE OH AS THE UPPER TROF AXIS CLOSES IN WITH COOLING
ALOFT. THERE CONTINUES TO BE A DEFORMATION BAND OF SORTS SHOWING UP
ON THE MODELS AS THE UPPER TROF CROSSES. HAVE ORIENTED THE POPS TO
REFLECT THIS THINKING...SLOWLY TRACKING IT E FROM SE OH/NE KY INTO C
WV BY PREDAWN HRS. THIS SHOULD COINCIDE WITH THE CHANGEOVER TO WET
SNOW. HAVE ALLOWED AROUND AN INCH TO FALL ACROSS SE OH/NE KY/W WV
WITH A COATING FURTHER E AS THE OVERALL BAND BEGINS TO WEAKEN.
ACROSS THE MOUNTAINS...PRECIP WILL CHANGE BACK TO SNOW AFTER
MIDNIGHT BUT PRECIP SHOULD BE SPOTTY UNTIL THE UPPER TROF AXIS AND
DEFORMATION BAND MOVES IN TOWARD MORNING.
AFTER COLLABORATION WITH SURROUNDING OFFICES...HAVE HOISTED A WINTER
WEATHER ADVISORY FOR RANDOLPH AND POCAHONTAS. DESPITE NOT REACHING
CRITERIA SNOW WISE...THERE IS EXPECTED TO BE SOME FREEZING RAIN IN
THE HIGHER ELEVATIONS WHICH MAY ACCRUE TO AROUND A TENTH OF AN
INCH. STARTED IT THIS AFTERNOON TO HIT THE INITIAL LIGHT
ACCUMULATION OF SNOW WITH THE ICE THREAT FROM 00 TO 06Z. ENDED IT AT
15Z WHEN THE UPPER TROF IS EXPECTED TO HAVE MOVED THRU.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
MODELS SHOW SYSTEM PULLING OUT EARLY SATURDAY. SOME MARGINAL UPSLOPE
THEN APPEARS POSSIBLE SATURDAY NIGHT AS NORTHWEST WINDS PULL IN SOME
COOLER AIR. 850 MB TEMPERATURES ARE MARGINAL FOR AUTO CONVECTION IN
THE LOWER LEVELS...SO WILL KEEP POPS IN THE CHANCE CATEGORY.
MODELS ARE A BIT FASTER WITH A CLIPPER MOVING THROUGH LATE
SUNDAY/SUNDAY EVENING. BOTH NAM AND GFS ARE SHOWING LOTS OF LIFT
WELL SOUTH OF THE LOW TRACK...BUT CLIPPERS USUALLY STRUGGLE TO
PRODUCE PRECIPITATION SOUTH OF THE LOW. THEREFORE...WILL SHOW A
NORTH SOUTH GRADIENT OF POPS.
COLDER AIR BEHIND THE CLIPPER ON MONDAY IS COLD ENOUGH FOR AUTO
CONVECTIVE CONDITIONS IN THE LOWER LEVELS...SO WILL KEEP HIGH POPS
OF SNOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE TREND THAT WE MENTIONED YESTERDAY REMAINS...THE CLIPPER COMING
EAST THROUGH THE MIDWEST INTO THE UPPER OHIO VALLEY...AT A HIGHER
LATITUDE REMAINS. AS A RESULT...WAS A BIT SLOWER BRINGING IN THE
COLDER AIR LATE SUNDAY NIGHT INTO MONDAY. POPS INCREASE NW TO SE
DURING SUNDAY NIGHT IN THE WAKE OF THE CLIPPER PASSING OUR LONGITUDE.
WE WILL BE CONSISTENT WITH POPS IN THE LIKELY CATEGORY MONDAY INTO
MONDAY EVENING BEFORE WANING FROM WEST TO EAST. AS MOISTURE
THINS...850 TEMPS BECOME COLDER...SO HELD ONTO SOME FLAKES EVEN
INTO TUESDAY EAST OF THE OHIO RIVER.
STILL DRY ON WEDNESDAY. WARMING 850 TEMPS WEDNESDAY NIGHT INTO
THURSDAY. NEXT WESTERN FRONT LONG ABOUT THURSDAY AFTERNOON.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
06Z FRIDAY THRU 06Z SATURDAY...
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH SOUTHWEST TODAY.
CIGS WILL LOWER AS PRECIP MOVES IN FROM THE SW THIS
AFTERNOON...FIRST ACROSS SW VA AND SE WV AFFECTING KBKW BY 18Z
WITH MVFR. PRECIPITATION OVERSPREADS THE REGION TOWARD EVENING
WITH MOST OF REMAINING TERMINALS EXPERIENCING MVFR CIGS IN PRECIP
BY 21Z. MVFR VSBY WILL LAG BEHIND A FEW HRS. EXPECT BULK OF PRECIP
THRU 00Z TO BE LIQUID...SAVE FOR A HR OR TWO OF A MIX FOR KBKW AT
ONSET.
CIGS WILL LOWER INTO IFR TONIGHT WITH A GRADUAL CHANGEOVER TO WET
SNOW. VSBY WILL FOLLOW SUITE WITH LOCALIZED VLIFR VSBY. IN THE
HIGH TERRAIN A VARIETY OF PRECIP TYPES CAN BE EXPECTED THIS
EVENING DEPENDING ON ELEVATION.
LOW LEVEL FLOW WILL BRIEFLY STRENGTHEN OUT OF SSE THIS
MORNING...PROVIDING FOR SOME 15 TO 20 KT GUSTS AT KBKW. OTHERWISE 5
TO 10 KT WINDS OUT OF NE FOR W TERMINALS AND E FOR THE MOUNTAIN
TERMINALS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING LOWERING OF CIGS INTO MVFR OR WORSE
ALONG WITH VSBY MAY VARY A FEW HRS THIS AFTERNOON/EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 01/23/15
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H M H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H M H H H H H H H H
PKB CONSISTENCY H H H M M H H H H H H H
CKB CONSISTENCY M M M H H H H H H H H H
AFTER 06Z SATURDAY...
IFR POSSIBLE EARLY SATURDAY MORNING IN SNOW. IFR POSSIBLE IN SNOW IN
THE HIGHER ELEVATIONS OF THE MOUNTAINS SUNDAY/SUNDAY NIGHT. IFR
POSSIBLE AREA WIDE IN SNOW SHOWERS MONDAY/MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 10 AM EST
SATURDAY FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...KTB
AVIATION...30
AREA FORECAST DISCUSSION
NWS TULSA OK
1118 PM CST THU JAN 22 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. CEILINGS
IN THE 5-10 THOUSAND FEET RANGE WILL PREVAIL THROUGH TONIGHT
ACROSS SE OK AND WC AR.
&&
.PREV DISCUSSION... /ISSUED 806 PM CST THU JAN 22 2015/
UPDATE...
POPS HAVE BEEN REDUCED IN THE SOUTH FOR TONIGHT. SEE DISCUSSION BELOW...
DISCUSSION...
THE LATEST SHORT RANGE DATA...INCLUDING THE HRRR AND RAP...SUGGEST
PRECIP SHOULD REMAIN TO OUR SOUTH AND EAST TONIGHT. THE WARM
CONVEYOR PRECIP HAS SHIFTED EAST...AND THE MAIN UPPER SYSTEM IS
STILL OUT AROUND THE BIG BEND REGION AND IS NOT GAINING ANY
LATITUDE. HAVE THUS PULLED BACK ON PRECIP CHANCES TONIGHT. THE 18Z
GFS IS THE ONLY SOLUTION THAT HAS PRECIP NORTH OF THE RED
RIVER...SO I HAVE LEFT SLIGHT CHANCES OR LOW END CHANCE POPS IN
THE FAR SOUTHEAST.
LACY
PREV DISCUSSION... /ISSUED 516 PM CST THU JAN 22 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. CEILINGS
IN THE 5-10 THOUSAND FEET RANGE WILL PREVAIL THROUGH TONIGHT
ACROSS SE OK AND WC AR.
PREV DISCUSSION... /ISSUED 300 PM CST THU JAN 22 2015/
DISCUSSION...
A LONGWAVE UPPER TROUGH WILL TRAVERSE THE SOUTHERN PLAINS OVERNIGHT
TONIGHT. RELATED PRECIPITATION IS EXPECTED TO REMAIN CONFINED TO FAR
SOUTHEAST OKLAHOMA AND WEST CENTRAL ARKANSAS. WITH TEMPERATURES
ACROSS THIS AREA FALLING FROM NEAR 40 THIS AFTERNOON TO THE LOW TO
MID 30S TONIGHT... SOME SNOWFALL WILL BE POSSIBLE... MAINLY AFTER
MIDNIGHT. LITTLE IF ANY ACCUMULATION IS EXPECTED. ALL PRECIPITATION
CHANCES WILL END BY MID MORNING FRIDAY AS THE UPPER TROUGH CONTINUES
EASTWARD.
ANOTHER SUSTAINED WARMING TREND WILL BEGIN SATURDAY... LASTING
THROUGH AT LEAST THURSDAY. DAILY MAX AND MIN TEMPERATURES WILL
EVENTUALLY RUN 10 TO 15 DEGREES ABOVE SEASONAL AVERAGES AS UPPER
RIDGING BUILDS ACROSS THE SOUTHERN PLAINS DURING THE UPCOMING WEEK.
FROM SUNDAY ON... AFTERNOON HIGHS IN THE 60S WILL BE COMMON ACROSS
THE FORECAST AREA... WITH SOME 70S POSSIBLE BY MID WEEK. OVERNIGHT
LOWS ARE EXPECTED TO REMAIN ABOVE FREEZING AREAWIDE... WHILE SLOWLY
INCREASING DURING THE MIDDLE OF THE WEEK. PRECIPITATION CHANCES WILL
BE MINIMAL THROUGHOUT THE NEXT 7 DAYS OR SO.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 25 49 31 57 / 0 0 0 0
FSM 35 48 29 54 / 10 10 0 0
MLC 33 48 29 56 / 10 10 0 0
BVO 25 49 27 56 / 0 0 0 0
FYV 30 45 26 51 / 0 0 0 0
BYV 29 45 28 50 / 0 0 0 0
MKO 31 47 30 55 / 0 0 0 0
MIO 27 47 29 52 / 0 0 0 0
F10 32 48 31 56 / 0 0 0 0
HHW 34 49 29 57 / 20 20 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS PORTLAND OR
223 PM PST FRI JAN 23 2015
.SYNOPSIS...A WARM FRONT WILL CONTINUE TO MIGRATE NORTH TONIGHT AS
HIGH PRESSURE ALOFT STRENGTHENS. THE UPPER RIDGE CONTINUES TO BUILD
OVER THE WEEKEND AND WILL RESULT IN UNSEASONABLY WARM TEMPERATURES
FOR THE COAST AND HIGHER TERRAIN INTO EARLY NEXT WEEK. INLAND VALLEYS
WILL BE TRAPPED UNDER STRONG INVERSIONS WITH COOLER TEMPERATURES AND
PERSISTENT FOG AND LOW CLOUDS. A FEW LIGHT SHOWERS APPEAR POSSIBLE
TOWARDS THE MIDDLE OF NEXT WEEK...BUT DRY WEATHER WILL LIKELY RETURN
LATER IN THE WEEK.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...KRTX DUAL-POL DOPPLER RADAR AT
21Z SHOWED A BROAD AREA OF GENERALLY LIGHT PRECIP ACROSS SW WA AND
MOST OF NW OREGON WEST OF THE CASCADES. LATEST RADAR TREND IN THE
PAST HOUR HAS SHOWN A DISTINCT BACK EDGE TO THE PRECIP ALONG THE
COAST. RAINFALL RATES AT KAST HAVE DIMINISHED TO A FEW HUNDREDTHS PER
HOUR...VERSUS THE .10 TO .15 PER HOUR LATE THIS MORNING. WATER VAPOR
IMAGERY WITH NAM AND GFS 500 MB HEIGHTS OVERLAYED INDICATES A 590+DM
500 MB HIGH PRES CENTER AROUND 30N 137W WITH THE 576 DM HEIGHT
CONTOUR PUSHING INTO SWRN WA.
NESDIS OPERATIONAL BLENDED TOTAL PRECIPITABLE WATER (TPW) IMAGERY AT
19Z SHOWED A GRADUAL DECREASE IN OVERALL TPW SINCE EARLIER THIS
MORNING. THE 19Z DATA SHOWED A SMALL AREA OF 1.25 INCH OR SO TPW OVER
EXTREME NW OREGON AND INTO SW WA. THE 12Z GFS AND NAM ISENTROPIC
ANALYSIS ALONG THE 290K SURFACE SHOWS THE BEST LIFT FOCUSED OVER SW
WA AND THE N OREGON COASTAL AREAS THROUGH 00Z SAT. BEST ISENTROPIC
LIFT THIS AFTERNOON LOOKS TO BE CONFINED TO INLAND ARAS N OF A
NEWPORT-TO-ALBANY LINE. THE 19Z HRRR RUN ALSO SHOWED THE PRECIP BAND
MOVING E OF THE CASCADES BY LATE AFTERNOON. DESPITE THE RATHER MOIST
AIR MASS ASSOCIATED WITH THE WARM FRONT...THE BULK OF THE PRECIP WILL
BE HEADED FOR WA. GFS 6-HR QPF FORECAST SHOWS AROUND A QUARTER INCH
FOR SW WA AND FAR NW OREGON WITH LITTLE TO NOTHING SOUTH OF KSLE.
PATTERN CHANGES RATHER DRAMATICALLY OVER THE WEEKEND...MORE TOWARD A
LATE-SPRING OR EARLY SUMMER REGIME INSTEAD OF WINTER. STRONG UPPER
LEVEL RIDGING WILL ASSERT ITSELF ACROSS THE REGION THIS WEEKEND.
OPTED TO REMOVE THE SAT AM POPS OVER THE N AS THE LATEST ECMWF AND
GFS SHOW THE PRECIP SHIELD SHOVED FURTHER N INTO WA. BY 18Z SAT THE
579 DM CONTOUR IS INTO SW WA. THE AIR MASS ALOFT WILL BE UNSEASONABLY
WARM FOR THIS TIME OF YEAR. THE 00Z NAEFS 850 MB TEMP JUMPS TO THE
99TH PERCENTILE 12Z SAT...THEN REACHES ALL-TIME MAX VALUES 06Z SUN
THROUGH MON. ANOTHER WAY TO LOOK AT IT IS BY THE STANDARDIZED
ANOMALY. 850 TEMPS ARE FORECAST TO BE 3-4 STANDARD DEVIATIONS ABOVE
NORMAL 18Z SAT THROUGH MON. THE ECMWF HAS BEEN VERY CONSISTENT IN
BRINGING 850 MB TEMPS UP TO +10 DEG C ACROSS THE WILLAMETTE VALLEY
SATURDAY...THEN +18 DEG C SUNDAY. TO GIVE AN IDEA OF HOW WARM THIS
AIR MASS IS... 850 MB TEMPS FORECAST BY NEARLY ALL MODELS SUNDAY ARE
WARMER THAN THE AVERAGE 850 MB TEMPERATURE IN AUGUST. GRANTED LOW SUN
ANGLE WILL LIMIT TEMPERATURES...BUT DO NOT BE SURPRISED IF AREAS IS
THE OREGON COAST RANGE AND CASCADE FOOTHILLS HIT 70 DEGREES. THE NAMM
MODEL SOUNDING FOR KPDX VALID SUN MORNING INDICATES 60-65 DEG AT
2000-2500 FT. INTERIOR VALLEY MAX TEMP FORECASTS WILL BE TRICKY.
SITES SUCH AS KPDX SHOULD HAVE A BETTER CHANCE OF CLEARING COMPARED
TO KSLE AND KEUG. IF THIS PATTERN OCCURED JUST A MONTH LATER...IN MID
TO LATE FEBRUARY...INTERIOR VALLEYS WOULD STAND A MUCH BETTER CHANCE
OF AT LEAST PARTIALLY MIXING OUT THE LOW-LEVEL INVERSIONS AND
REACHING AT LEAST 60 DEG.
THE STRONG UPPER LEVEL RIDGE WILL LIKELY RESULT IN A BUILDING COOL
POOL IN THE WILLAMETTE VALLEY. THIS SHOULD GENERATE A MESOSCALE HIGH
PRESSURE SYSTEM INLAND...AND KEEP LIGHT OFFSHORE FLOW ALONG THE COAST
SUNDAY WITH THE END RESULT BEING MAX TEMPS IN THE MID TO UPPER 60S.
IT IS PRETTY SAFE TO SAY AT LEAST A COUPLE MAX TEMP RECORDS WILL
FALL. 850MB TEMPS DIP JUST A BIT MON...BUT SHOULD STILL SEE PLENTY OF
60S IN THE OREGON COAST RANGE AND CASCADE FOOTHILLS. ONE OTHER
CONCERN WILL BE AIR QUALITY FOR THE INTERIOR CENTRAL AND SRN VALLEYS
DUE TO THE IMPENDING STRONG VALLEY INVERSIONS. WEISHAAR
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY...VALLEY FOG AND LOW CLOUDS
LOOK TO STICK AROUND THROUGH EARLY TUESDAY. HOWEVER...AS THE FLOW
PATTERN BECOMES MORE SOUTHERLY ON TUESDAY WE CAN EXPECT TO SEE AN
INCREASE IN MOISTURE FROM THE SOUTH. BUMPED UP THE POPS SLIGHTLY TO
ACCOUNT FOR A CHANCE OF SOME SCATTERED SHOWERS. A WEAK FRONT LOOKS
TO MOVE THROUGH ON LATE TUESDAY/EARLY WEDNESDAY AND IS THE MOST
PROMISING CHANCE OF RAIN IN THE UPCOMING WEEK...BUT DETAILS ARE
STILL A BIT SKETCHY. THE UPPER LEVEL RIDGE LOOKS TO REBUILD LATE
NEXT WEEK BRINGING THE RETURN OF VALLEY FOG AND LOW CLOUDS...AND
BENIGN CONDITIONS. AFTERNOON TEMPERATURES THROUGH THE EXTENDED
FORECAST WILL CONTINUE TO BE UNSEASONABLY WARM AT MOST LOCATIONS. /64
&&
.AVIATION...CURRENTLY MVFR/IFR CIGS AND VIS ALONG THE
COAST...WHILE INLAND SITES ARE PRIMARILY VFR. CIGS AND VIS OVER THE
NORTH OR/SOUTH WA COAST WILL LIKELY LOWER TO IFR OVERNIGHT
TONIGHT AS RAIN CONTINUES ALONG THE COAST AND MOISTURE CONTINUES
TO BE PUSHED ONSHORE. THE CENTRAL OR COAST...THOUGH...WILL LIKELY
BOUNCE BETWEEN MVFR/IFR OVERNIGHT AS MOST OF THE MOISTURE REMAINS
TO THE NORTH. INLAND SITES WILL SEE CIGS AND VIS LOWER TO MVFR/IFR
TONIGHT WITH FOG DEVELOPING EARLY SATURDAY IN THE SOUTH AND
CENTRAL WILLAMETTE VALLEY. PATCHY FOG IS POSSIBLE IN THE NORTH
WILLAMETTE VALLEY...BUT MAINLY IN AREAS PROTECTED FROM THE WIND SUCH
AS KHIO. MODELS ARE SUGGESTING THAT STRATUS SHOULD LIFT TO VFR BY
LATE MORNING OR EARLY AFTERNOON ACROSS THE AREA...BUT THERE IS A
CHANCE IF KEUG SEES ANY CLEARING TONIGHT THAT DENSE FOG COULD
DEVELOP...KEEPING THIS SITE MVFR/IFR ALL DAY SATURDAY.
KPDX AND APPROACHES...VFR CONDITIONS EXPECTED TO CONTINUE INTO THE
OVERNIGHT HOURS...THOUGH VISUAL APPROACHES WILL LIKELY BECOME
LIMITED AS CIGS LOWER TO AROUND 030 TO 040 AFTER 01Z THIS
EVENING. CIGS CONTINUE TO LOWER EARLY SATURDAY...FALLING TO AROUND
025 AFTER 12Z...WITH MVFR VIS AS WELL. CONDITIONS EXPECTED TO
IMPROVE TO VFR BY 19Z SATURDAY. -MCCOY
&&
.MARINE...WARM FRONT HAS MOVED ONSHORE...AND GUSTY SOUTHERLY WINDS
ARE OCCURRING OVER THE WATERS. WINDS AROUND 20 TO 25 KTS GUSTING
TO 30 KTS ARE BEING OBSERVED AT BUOY 29. GUSTY WINDS OVER THE
WATERS COULD EXTEND INTO SATURDAY AFTERNOON AS A LOW PRESSURE
CENTER REMAINS WELL NORTHWEST OF THE REGION. MODELS ARE NOT IN
GOOD AGREEMENT ON THE TIMING THAT WINDS WILL WEAKEN...BUT GFS AND
NAM ARE LEANING TOWARDS WINDS PERSISTING UNTIL SATURDAY
AFTERNOON SO EXTENDED SMALL CRAFT ADVISORY FOR WINDS OVER THE
NORTHERN OUTER WATERS TO INCLUDE SATURDAY AFTERNOON.
SEAS ARE CURRENTLY AROUND 10 FT AND WILL CONTINUE TO INCREASE...
PEAKING AROUND 13 FT LATER THIS EVENING. SEAS WILL REMAIN AROUND
10 TO 12 FT THROUGH SUNDAY BEFORE DROPPING BELOW 10 FT LATE
SUNDAY OR EARLY MONDAY. -MCCOY
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST SATURDAY FOR
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
TO 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST SUNDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT
60 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST THIS EVENING FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
OUT 10 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST THIS AFTERNOON
FOR WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST SATURDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
741 PM EST SAT JAN 24 2015
.SYNOPSIS...
ANOTHER WEAK UPPER TROF WILL BRING COLDER AIR TO CENTRAL PA
TONIGHT...ALONG WITH SNOW SHOWERS FOR WESTERN AND NORTHERN
SECTIONS. AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF
PENNSYLVANIA SUNDAY NIGHT WITH ANOTHER WEAKER CLIPPER TAKING THE
SAME PATH MONDAY NIGHT AND EARLY TUESDAY. HIGH PRESSURE WILL BUILD
OVER THE REGION MID WEEK...FOLLOWED BY ANOTHER CLIPPER LATE
THURSDAY.
&&
.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
730 PM UPDATE...
FZRA HAS BEEN FALLING AT KBFD FOR A WHILE. CONSIDERING THAT
ROUGHLY SIMILAR CONDITIONS EXISTS ACROSS MOST OF THE NRN TIER AND
ALLEGHENIES/LAURELS...THE FZRA ADVY HAS BEEN EXPANDED IN
COLLABORATION WITH NEIGHBORING OFFICES. AGAIN...LITTLE
ACCUMULATIONS IS EXPECTED ON ROADS DUE TO RECENT TREATMENTS. BUT
SIDEWALKS AND BRIDGES/OVERPASSES MAY BECOME SLIPPERY.
AGAIN...THESE CONDITIONS ARE NOT EXPECTED TO LAST FOR MUCH MORE
THAN A FEW MORE HOURS. FORCING/LIFT FROM THE SHORTWAVE TROUGH NOW
MOVING INTO NY SHOULD WANE AS IT PUSHES STEADILY EASTWARD.
DOWNSLOPE DRYING TO THE SE OF THE RIDGES SHOULD HELP TO REDUCE THE
POSSIBILITY OF ICING THERE. WILL ALSO ISSUE AN SPS TO HIGHLIGHT
POSS FZDZ IN THE RIDGE AND VALLEY REGION...AS DEWPOINT SPREADS ARE
STILL AOB 5F. IPT/SEG/MDT/ETC. ARE VERY MUCH DRIER AND SHOULD
CONTINUE TO BE SO AS THE WINDS STAY OUT OF THE WEST. THIS WILL
KEEP CIGS HIGHER AND HELP TO EVAPORATE ANY DZ AS IT TRIES TO FALL
FROM SO HIGH.
530 PM UPDATE...
MANY OBS OF FREEZING FOG AND FREEZING DRIZZLE OVER NW PA AND WRN
NY AS MOISTURE IS CARRIED IN WHILE A SHORT WAVE TROUGH SWINGS
ACROSS THE LOWER GREAT LAKES. THIS PATCH OF FZDZ SHOULD NOT LAST
MORE THAN A FEW HOURS JUDGING BY RAP BUFKIT SOUNDINGS WHICH HAVE
THE COLUMN COOLING ENOUGH AT BFD TO MAKE SURE IT IS ALL SNOW. WILL
RUN A FZRA ADVY THRU 06Z TO COVER THIS HAZARD.
PREV...
A PARADE OF NORTHERN STREAM SHORTWAVES WILL MAINTAIN AN ACTIVE
WINTRY PATTERN OVER CENTRAL PA FOR THE FORESEEABLE FUTURE.
AS OUR EARLY WEEKEND STORM CONTINUES TO SCOOT OFFSHORE...A WEAKER
UPPER LEVEL TROF WILL SPREAD ADDITIONAL SNOW SHOWERS AND LIGHT
ACCUMS INTO THE WEST TONIGHT...GENERALLY ALONG AND WEST OF THE
ALLEGHENY FRONT. THE 5H SHEAR AXIS ASSOCIATED THIS THIS UPPER TROF
WILL BE ALIGNED FROM NORTHWEST TO SOUTHEAST FROM LAKE SUPERIOR TO
THE DEL MARVA PENINSULA BY 12Z SUNDAY...WHILE A VIGOROUS UPPER
TROF DROPS THROUGH THE UPPER MIDWEST TO THE MID MISSISSIPPI
VALLEY.
PASSAGE OF SHORTWAVE THIS EVENING SHOULD PRODUCE -SHSN ACROSS THE
ALLEGHENY PLATEAU WITH A SMALL ACCUM OF AN INCH OR LESS. LATE
TONIGHT...SHORTWAVE PASSES EAST OF THE STATE...CAUSING -SHSN TO
TAPER OFF OVR THE NW MTNS. HOWEVER...RESIDUAL UPSLOPE FLOW INTO
THE LAURELS WILL KEEP THE -SHSN GOING DOWN THERE. A DOWNSLOPING
WEST WIND SHOULD RESULT IN NOTHING MORE THAN FLURRIES EAST OF THE
MTNS TONIGHT. WIDESPREAD STRATOCU SHOULD HOLD READINGS UP TONIGHT
WITH LOWS IN THE 20S.
&&
.SHORT TERM /7 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
LITTLE CHANGE FROM PREVIOUS EXPECTED ON SUNDAY. SOME LIGHT
OROGRAPHIC SNOW MAY BE ONGOING SUNDAY MORNING ACROSS THE LAUREL
HIGHLANDS. WILL CONTINUE TO FOCUS ON THE APPROACHING POTENT
CLIPPER WHICH PROMISES TO BRING ANOTHER LIGHT TO LOCALLY MODERATE
SNOW ACCUMULATION. THIS TIME IT`S THE LAURELS MOST SHARPLY FOCUSED
IN ITS CROSS HAIRS FOR SUNDAY NIGHT INTO MONDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
CLIPPER WILL BRING SOME SNOW TO THE AREA LATE SUNDAY AFT INTO
MONDAY MORNING. ENERGY WILL QUICKLY TRANSFER TO THE COASTAL LOW
DURING THE DAY ON MONDAY. EXPECT THE HEAVIEST SNOW ACROSS THE
SOUTH CENTRAL PART OF THE STATE...GIVEN NW TO SE WARM FRONT.
THUS LAUREL HIGHLANS WILL LIKELY SEE HIGHEST AMTS.
DID EDGE POPS AND AMTS UP A LITTLE ACROSS THE SE...TO FIT
IN BETTER WITH LWX.
ALSO DID UP POPS ON TUESDAY. CONCERN IS THAT INVERTED
TROUGH COULD KEEP SNOW ACROSS THE WEST INTO TUE...AND COASTAL
STORM THAT DEEPENS EXTREMELY FAST MAY WRAP SNOW AROUND TO THE
WEST SIDE...A CONCERN FOR THE EAST AND SE. BLOCKING HIGH TO THE
NORTH.
STILL A LITTLE EARLY FOR AN ADVISORY ACROSS THE SOUTH.
TIGHT TEMP GRADIENT BETWEEN NY AND MD...SOME ADJUSTMENTS TO
TEMPS MONDAY INTO TUE.
WED STILL LOOKS LIKE A DRY DAY.
ANOTHER FRONTAL SYSTEM FOR LATE THU.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
DECK OF LOWER STRATUS ASSOCIATED WITH SHORTWAVE TROF ROTATING
THROUGH BEHIND DEPARTING STORM NOW OVERSPREADING THE REGION WITH
MVFR TO LIFR CONDITIONS. DOWNSLOPING MAY BE ENOUGH TO KEEP
SOUTHEAST AIRFIELDS IN VFR CONDITIONS...BUT ELSEWHERE LOOK FOR
RESTRICTIONS IN CIGS MUCH OF THE OVERNIGHT.
SOME FREEZING DRIZZLE IS NOW BEING PRODUCED OVER THE NORTHWEST
AIRFIELDS...WITH KBFD REPORTING INTERMITTENT -FZRA. THESE
CONDITIONS LIKELY THROUGH 04Z-06Z.
AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF PENNSYLVANIA SUNDAY
NIGHT INTO MONDAY...BRINGING ANOTHER ROUND OF SNOW WITH IFR
CONDITIONS TO THE REGION. THIS WILL LIKELY IMPACT MOST TAF SITES
AFTER 00Z TOMORROW...BUT SOME AFFECTS POSSIBLE KJST AND KAOO
BEFORE THIS TIME...WHICH IS REFLECTED IN THE TAFS. EXPECT A
PROLONGED PERIOD OF RESTRICTIONS INTO MON NIGHT.
OUTLOOK...
SUN...MVFR TO IFR IN THE WESTERN AND NORTHERN MOUNTAINS...VFR
ELSEWHERE.
SUN NITE...SNOW RAPIDLY OVERSPREADING FROM SW TO NE...BRINGING IFR
CONDITIONS TO THE ENTIRE REGION OVERNIGHT.
MON...WIDESPREAD IFR/MVFR IN SNOW...GRADUAL IMPROVEMENT OVERNIGHT.
TUE...AREAS MVFR IN SHSN WEST...AND ANY LINGERING SNOW IN THE EAST.
WED...NO SIG WEATHER EXPECTED.
THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM
THE WEST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 1 AM EST SUNDAY FOR PAZ004>006-
010>012-017-018-024-033-037-041-042.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR
LONG TERM...MARTIN
AVIATION...JUNG
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
723 PM EST SAT JAN 24 2015
.SYNOPSIS...
ANOTHER WEAK UPPER TROF WILL BRING COLDER AIR TO CENTRAL PA
TONIGHT...ALONG WITH SNOW SHOWERS FOR WESTERN AND NORTHERN
SECTIONS. AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF
PENNSYLVANIA SUNDAY NIGHT WITH ANOTHER WEAKER CLIPPER TAKING THE
SAME PATH MONDAY NIGHT AND EARLY TUESDAY. HIGH PRESSURE WILL BUILD
OVER THE REGION MID WEEK...FOLLOWED BY ANOTHER CLIPPER LATE
THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
530 PM UPDATE...
MANY OBS OF FREEZING FOG AND FREEZING DRIZZLE OVER NW PA AND WRN
NY AS MOISTURE IS CARRIED IN WHILE A SHORT WAVE TROUGH SWINGS
ACROSS THE LOWER GREAT LAKES. THIS PATCH OF FZDZ SHOULD NOT LAST
MORE THAN A FEW HOURS JUDGING BY RAP BUFKIT SOUNDINGS WHICH HAVE
THE COLUMN COOLING ENOUGH AT BFD TO MAKE SURE IT IS ALL SNOW. WILL
RUN A FZRA ADVY THRU 06Z TO COVER THIS HAZARD.
PREV...
A PARADE OF NORTHERN STREAM SHORTWAVES WILL MAINTAIN AN ACTIVE
WINTRY PATTERN OVER CENTRAL PA FOR THE FORESEEABLE FUTURE.
AS OUR EARLY WEEKEND STORM CONTINUES TO SCOOT OFFSHORE...A WEAKER
UPPER LEVEL TROF WILL SPREAD ADDITIONAL SNOW SHOWERS AND LIGHT
ACCUMS INTO THE WEST TONIGHT...GENERALLY ALONG AND WEST OF THE
ALLEGHENY FRONT. THE 5H SHEAR AXIS ASSOCIATED THIS THIS UPPER TROF
WILL BE ALIGNED FROM NORTHWEST TO SOUTHEAST FROM LAKE SUPERIOR TO
THE DEL MARVA PENINSULA BY 12Z SUNDAY...WHILE A VIGOROUS UPPER
TROF DROPS THROUGH THE UPPER MIDWEST TO THE MID MISSISSIPPI
VALLEY.
PASSAGE OF SHORTWAVE THIS EVENING SHOULD PRODUCE -SHSN ACROSS THE
ALLEGHENY PLATEAU WITH A SMALL ACCUM OF AN INCH OR LESS. LATE
TONIGHT...SHORTWAVE PASSES EAST OF THE STATE...CAUSING -SHSN TO
TAPER OFF OVR THE NW MTNS. HOWEVER...RESIDUAL UPSLOPE FLOW INTO
THE LAURELS WILL KEEP THE -SHSN GOING DOWN THERE. A DOWNSLOPING
WEST WIND SHOULD RESULT IN NOTHING MORE THAN FLURRIES EAST OF THE
MTNS TONIGHT. WIDESPREAD STRATOCU SHOULD HOLD READINGS UP TONIGHT
WITH LOWS IN THE 20S.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
LITTLE CHANGE FROM PREVIOUS EXPECTED ON SUNDAY. SOME LIGHT
OROGRAPHIC SNOW MAY BE ONGOING SUNDAY MORNING ACROSS THE LAUREL
HIGHLANDS. WILL CONTINUE TO FOCUS ON THE APPROACHING POTENT
CLIPPER WHICH PROMISES TO BRING ANOTHER LIGHT TO LOCALLY MODERATE
SNOW ACCUMULATION. THIS TIME IT`S THE LAURELS MOST SHARPLY FOCUSED
IN ITS CROSS HAIRS FOR SUNDAY NIGHT INTO MONDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
CLIPPER WILL BRING SOME SNOW TO THE AREA LATE SUNDAY AFT INTO
MONDAY MORNING. ENERGY WILL QUICKLY TRANSFER TO THE COASTAL LOW
DURING THE DAY ON MONDAY. EXPECT THE HEAVIEST SNOW ACROSS THE
SOUTH CENTRAL PART OF THE STATE...GIVEN NW TO SE WARM FRONT.
THUS LAUREL HIGHLANS WILL LIKELY SEE HIGHEST AMTS.
DID EDGE POPS AND AMTS UP A LITTLE ACROSS THE SE...TO FIT
IN BETTER WITH LWX.
ALSO DID UP POPS ON TUESDAY. CONCERN IS THAT INVERTED
TROUGH COULD KEEP SNOW ACROSS THE WEST INTO TUE...AND COASTAL
STORM THAT DEEPENS EXTREMELY FAST MAY WRAP SNOW AROUND TO THE
WEST SIDE...A CONCERN FOR THE EAST AND SE. BLOCKING HIGH TO THE
NORTH.
STILL A LITTLE EARLY FOR AN ADVISORY ACROSS THE SOUTH.
TIGHT TEMP GRADIENT BETWEEN NY AND MD...SOME ADJUSTMENTS TO
TEMPS MONDAY INTO TUE.
WED STILL LOOKS LIKE A DRY DAY.
ANOTHER FRONTAL SYSTEM FOR LATE THU.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
DECK OF LOWER STRATUS ASSOCIATED WITH SHORTWAVE TROF ROTATING
THROUGH BEHIND DEPARTING STORM NOW OVERSPREADING THE REGION WITH
MVFR TO LIFR CONDITIONS. DOWNSLOPING MAY BE ENOUGH TO KEEP
SOUTHEAST AIRFIELDS IN VFR CONDITIONS...BUT ELSEWHERE LOOK FOR
RESTRICTIONS IN CIGS MUCH OF THE OVERNIGHT.
SOME FREEZING DRIZZLE IS NOW BEING PRODUCED OVER THE NORTHWEST
AIRFIELDS...WITH KBFD REPORTING INTERMITTENT -FZRA. THESE
CONDITIONS LIKELY THROUGH 04Z-06Z.
AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF PENNSYLVANIA SUNDAY
NIGHT INTO MONDAY...BRINGING ANOTHER ROUND OF SNOW WITH IFR
CONDITIONS TO THE REGION. THIS WILL LIKELY IMPACT MOST TAF SITES
AFTER 00Z TOMORROW...BUT SOME AFFECTS POSSIBLE KJST AND KAOO
BEFORE THIS TIME...WHICH IS REFLECTED IN THE TAFS. EXPECT A
PROLONGED PERIOD OF RESTRICTIONS INTO MON NIGHT.
OUTLOOK...
SUN...MVFR TO IFR IN THE WESTERN AND NORTHERN MOUNTAINS...VFR
ELSEWHERE.
SUN NITE...SNOW RAPIDLY OVERSPREADING FROM SW TO NE...BRINGING IFR
CONDITIONS TO THE ENTIRE REGION OVERNIGHT.
MON...WIDESPREAD IFR/MVFR IN SNOW...GRADUAL IMPROVEMENT OVERNIGHT.
TUE...AREAS MVFR IN SHSN WEST...AND ANY LINGERING SNOW IN THE EAST.
WED...NO SIG WEATHER EXPECTED.
THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM
THE WEST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 1 AM EST SUNDAY FOR PAZ004>006-
010-011.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR
LONG TERM...MARTIN
AVIATION...JUNG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1024 PM EST SAT JAN 24 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD BACK INTO THE REGION ON SUNDAY...BEFORE
ANOTHER LOW PRESSURE AREA AND TRAILING UPPER LEVEL DISTURBANCE MOVE
THROUGH MONDAY AND TUESDAY. HIGH PRESSURE RETURNS DURING THE LATTER
HALF OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1020 PM EST...WINDS HAVE SUDDENLY COME UP STRONGLY BEHIND THE
PASSING APPALACHIANS WAVE...WITH BOONE TO WEST JEFFERSON GUSTING 40
TO 50 KT...AND SOME HIGHER PEAKS FROM MT MITCHELL TO GRANDFATHER
STARTING TO SHOW SOLID ADVISORY VALUES. THE LATEST RAP RUNS HAVE NW
WINDS INCREASING FURTHER THROUGH 06Z...SO A WIND ADVISORY WILL BE
ISSUED FOR THE NRN THREE COUNTIES UNTIL 6 AM...WHEN THE GRADIENT
SHOULD HAVE SLACKENED.
OTHERWISE...A BRIEF PERIOD OF RESIDUAL NW FLOW MOISTURE BEHIND A
SHORTWAVE CROSSING THE APPALACHIANS WILL PEAK AROUND 06Z. ISOLD
LIGHT SNOW SHOWERS OR PATCHY FREEZING DRIZZLE WILL BE POSSIBLE...BUT
CHANCES LOOK TOO SMALL THIS FAR SOUTH OF THE BETTER MOISTURE TO
FEATURE ANY SNOW/ICE AMOUNTS. THE OTHER CONCERN WILL BE FOR VERY
PATCHY BLACK ICE IN LOCATIONS WHERE WET ROADS MIGHT HAVE LINGERED
INTO THE EVENING HOURS FROM EARLY DAY PRECIPITATION. ALTHOUGH THIS
COULD BE A MINOR CONCERN FROM THE NC MTNS TO PARTS OF THE NW
PIEDMONT...THERE APPEARS TO HAVE BEEN JUST ENOUGH DRYING THIS
AFTN/EVENING TO NOT REQUIRE AN SPS. EXPECT OVERNIGHT LOWS AROUND
NORMAL.
SHORT WAVE RIDGING WILL DEVELOP OVER THE AREA SUNDAY AHEAD OF A
STRONG CLIPPER SYSTEM MOVING INTO THE MID MISSISSIPPI VALLEY. LOW
LEVEL FLOW WILL BECOME SLY AHEAD OF THE ASSOCIATED SFC LOW. AFTER
CLEARING SKIES ACROSS THE MTNS DURING THE MORNING AS LOW LEVEL
MOISTURE DEPARTS...CLOUDS MOVE BACK IN IN THE DEVELOPING WAA
PATTERN. ISOLATED SHRA MAY ALSO DEVELOP ACROSS THE MTNS VERY LATE IN
THE DAY AS DEEP MOISTURE INCREASES...BUT NO SIGNIFICANT QPF IS
EXPECTED. CLOUDS WILL INCREASE LATE IN THE DAY OUTSIDE OF THE
MTNS...BUT MOSTLY SUNNY SKIES WILL PREVAIL FOR THE BULK OF THE DAY.
HIGHS WILL BE A FEW DEGREES ABOVE NORMAL ACROSS THE CWFA.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM SATURDAY...THE POTENT CLIPPER SYSTEM WILL CROSS THE
CWFA SUNDAY NIGHT THRU MONDAY MORNING PER LATEST CONSENSUS. GUIDANCE
CONTINUES TO BE IN GOOD AGREEMENT ON THE TIMING. BEST Q-VECTOR
CONVERGENCE LOOKS TO BE AROUND 00-06Z MON...SHIFTING EAST BY 12Z.
STEEP LOW-MID LVL LAPSE RATES AND DECENT MOISTURE SHUD RESULT IN
GOOD COVERAGE OF PRECIP ACRS THE HIGH TERRAIN OVERNIGHT...WITH SOME
ACTIVITY BEING ABLE TO DEVELOP EAST OF THE MTNS. WITH MID LVL
THICKNESSES CRASHING...COUPLED WITH WEAK SBCAPE (UP TO 150
J/KG)...MAY SEE CONVECTIVE SNOW SHWRS ACRS THE MTNS. IN THE LWR
ELEVATIONS...ALL INDICATIONS ARE THAT THE SFC-BASED WARM LAYER WILL
PROBABLY JUST BE TOO WARM. IF THE BEST FORCING IS ABLE TO OCCUR
DURING THE WEE MORNING HOURS...CANNOT RULE OUT SPOTTY SNOW SHWRS
ACRS NE GA AND THE WRN UPSTATE. BASED ON CURRENT TIMING...IT LOOKS
LIKE THE NC FOOTHILLS AND PIEDMONT HAVE A BETTER SHOT AT SEEING A FEW
FLAKES...BUT EVEN THERE...NOT EXPECTING ANY WIDESPREAD ACCUMS. EVEN
IN THE MTNS...ACCUMS MAY STRUGGLE TO REACH ADVISORY CRITERIA...AS
LLVL FLOW WILL BE OUT OF THE WEST-SOUTHWEST OVERNIGHT. FOR TEMPS...I
WENT CLOSE TO THE MOS CONSENSUS...MAINLY IN THE UPR 20S TO MID 30S
MTNS AND UPR 30S-40 PIEDMONT.
AS THE MID LVL LOW PASSES TO THE EAST MONDAY MORNING...LLVL FLOW
WILL VEER TO NWLY...BUT NEVER GETS ALL THAT STRONG. SO ONLY LIGHT
ADDITIONAL NW FLOW SNOW ACCUMS ARE EXPECTED ALONG THE TN LINE DURING
THE DAY. EAST OF THE MTNS...FCST SNDGS SHOW LINGERING LLVL MOISTURE
WITHIN WEAK NW FLOW...BUT FORCING SHUD WANE FOR ANY PRECIP. TEMPS
WILL WARM INTO THE MID 30S TO LWR 40S IN THE MTNS...AND UPR 40S TO
LWR 50S ACRS THE PIEDMONT.
MONDAY NIGHT AND TUESDAY...ANOTHER SHORTWAVE WILL DIVE SOUTHEAST
ACRS THE OHIO VALLEY...AND REINFORCE NWLY FLOW ATOP THE CWFA. IN
FACT...THE 12Z NAM AND GFS AGREE ON BETTER OVERALL NW FLOW SETUP
ACRS THE SOUTHERN APPALACHIANS...ESPECIALLY AROUND MIDDAY TUESDAY.
ON THE PLAN VIEW...THE 925-850 MB FLOW ALSO SEEMS TO COME OFF THE
GREAT LAKES TO THE NC MTNS. SO MAY SEE DIURNALLY-ENHANCED CONVECTIVE
SNOW SHWRS DEVELOPING ACRS ERN KY/TN...THEN INTO THE NC
MTNS...PRODUCING A QUICK 1-2" OF SNOW. I WILL PLAN TO ADD A MENTION
OF SNOW ACCUM IN THE HWO ALONG THE TN BORDER FOR TUESDAY.
OTHERWISE...EXPECT GENERALLY MOSTLY CLEAR SKIES AND BELOW NORMAL
TEMPS ACRS THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM SAT...THE PERSISTENT DEEP TROUGH OVER THE ERN SEABOARD
WILL FINALLY MOVE OFF THE EAST COAST WEDNESDAY ALLOWING A SHORT RIDGE
AND HIGH PRESSURE TO BUILD ACROSS THE CWFA. COLD ADVECTION AND MOIST
NW FLOW WILL CONTINUE TUE NIGHT INTO WED...WITH POPS ACCORDINGLY
CONTINUED NEAR THE TENN BORDER. DRY AND SETTLED WEATHER RETURN
BRIEFLY BEFORE THE NEXT CLIPPER MOVES IN LATE THURSDAY. THE CLIPPER
WILL HAVE ABSORBED A WEAK WAVE IN THE SRN STREAM AND IS PROGGED TO
PUSH A WEAK COLD FRONT INTO THE DEEP SOUTH AND CAROLINAS THU NIGHT.
CHC POPS FOR THE UPSLOPE AREAS OF THE MTNS WILL BE ADVERTISED...IN
ADDITION TO SCHC POPS IN THE PIEDMONT AFFORDED BY THE PRESENCE OF
SOME LLVL FORCING. HIGH PRESSURE RETURNS IN THE WAKE OF THE FRONT AS
THE UPPER FLOW BECOMES MORE ZONAL. REGARDING FURTHER EVOLUTION...THE
24/12Z RUNS OF THE GFS AND EC DIVERGE BY THE WEEKEND. EC BRINGS
ANOTHER CLIPPER INTO THE CENTRAL APPALACHIANS BY SATURDAY NIGHT WITH
AN ERN TROUGH DEVELOPING AFTERWARD. GFS IS A BIT MORE ACTIVE WITH THE
SRN STREAM DURING THE SAME PERIOD...SHOWING RETURN FLOW OVER THE HIGH
WHICH DEVELOPS INTO A WEDGE. BOTH MODELS KEEP US DRY THRU SATURDAY
HOWEVER. TEMPS WILL REMAIN IN A SEASONABLE RANGE THRU THE FCST
PERIOD...STARTING OFF A COUPLE DEGREES BELOW NORMALS...BUT WARMING
WED-THU PRIOR TO THE FROPA AND A SUBSEQUENT RETURN OF READINGS A BIT
BELOW NORMAL.
&&
.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
AT KCLT...ANTICIPATE WINDS REMAINING JUST N OF W THROUGH MUCH OF THE
NIGHTTIME HOURS...BEFORE TURNING SW AROUND DAYBREAK AND THEN BACKING
TO SRLY THROUGH SUNDAY. LITTLE MORE THAN INCREASING HIGH CLOUDS IS
EXPECTED AHEAD OF THE NEXT APPROACHING CLIPPER THROUGH SUNDAY AFTN.
ELSEWHERE...NW FLOW MOISTURE PEAKING AROUND 06Z TONIGHT COULD
PRODUCE SOME MVFR TO LOWER VFR CLOUDS NEAR THE SPINE OF THE SRN
APPALACHIANS...BUT THESE LOWER CLOUDS ARE NOT EXPECTED TO REACH THE
AIRFIELD AT KAVL. OTHERWISE...ANTICIPATE GRADUALLY INCREASING HIGHER
LEVEL CLOUDS THROUGH SUNDAY AHEAD OF THE NEXT APPROACHING CLIPPER
SYSTEM. FLOW WILL STEADILY BACK FROM WSW TO SW TO SRLY THROUGH
SUNDAY...EXCEPT NW AT KAVL EARLY BECOMING SRLY MORE ABRUPTLY AROUND
MIDDAY SUNDAY.
OUTLOOK...A SERIES OF CLIPPER SYSTEMS WILL BRING SNOW CHANCES MAINLY
TO THE MOUNTAINS EARLY IN THE WEEK. ANY RESTRICTIONS AND SNOW
SHOWERS WOULD BE POSSIBLE AT KAVL...WITH MAINLY VFR CONDITIONS
LIKELY ELSEWHERE.
CONFIDENCE TABLE...
03-09Z 09-15Z 15-21Z 21-00Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND ADVISORY UNTIL 6 AM EST SUNDAY FOR NCZ033-049-050.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...HG/RWH
SHORT TERM...ARK
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
100 AM EST FRI JAN 23 2015
.SYNOPSIS...
A DEVELOPING AREA OF LOW PRESSURE WILL TRACK ALONG THE GULF AND
SOUTH ATLANTIC COASTS THROUGH FRIDAY NIGHT...BEFORE MOVING UP THE
EAST COAST OVER THE WEEKEND. THE LOW WILL BRING WIDESPREAD
PRECIPITATION OVER OUR AREA FRIDAY INTO SATURDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN ON SUNDAY...BEFORE A COLDER LOW PRESSURE SYSTEM
AFFECTS THE FORECAST AREA SUNDAY NIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1255 AM...A BAND OF LIGHT PRECIP CONTINUES TO OOZE NORTH
ACROSS CENTRAL GEORGIA...AND WILL MAKE A RUN AT THE LOWER SC AND
NORTHEAST GEORGIA PIEDMONT OVER THE NEXT COUPLE OF HOURS. AT THIS
HOUR...SURFACE WET BULB TEMPS ARE WELL ABOVE FREEZING ACROSS THE
SOUTHERN HALF OF THE AREA...UPPER 30S TO LOWER 40S. THUS...ONLY RAIN
WITH PERHAPS A SLEET PELLET OR TWO MIXED IN IS EXPECTED ACROSS MUCH
OF THE UPSTATE AND NORTHEAST GEORGIA. P-TYPE SHOULD BECOME MORE
INTERESTING AS PRECIP MOVES INTO THE MOUNTAINS AND FAR NC NORTHERN
PIEDMONT/FOOTHILL AREAS LATER THIS MORNING...BUT THIS WON/T OCCUR
FOR SEVERAL MORE HOURS.
AS OF 945 PM EST...THE LEADING EDGE OF LIGHT PRECIPITATION FALLING
FROM MID LEVEL CLOUD BASES IS APPROACHING THE CWFA FROM THE SW LATE
THIS EVENING...AND THE ONSET OF POP HAS BEEN ACCELERATED FOR THE
NIGHTTIME HOURS. NO CHANGES WILL BE MADE TO THE ADVISORY AREA SINCE
THE LATEST RAP AND INCOMING 00Z NAM PROFILES LOOK VERY SIMILAR TO
THE PREVIOUS MODEL RUNS.
OTHERWISE...WATER VAPOR IMAGERY CONTINUES TO SHOW THE MAIN DRIVING
UPPER LOW MOVING INTO W TX LATE THIS EVENING...WITH SFC DEVELOPMENT
CONTINUING ALONG THE WRN GULF COAST AHEAD OF THIS FEATURE. DEEPER
LAYER MOISTURE AND RAPIDLY INCREASING ISENTROPIC LIFT WILL START
SPREADING INTO THE EXTREME SW SECTIONS 09Z TO 12Z...SPREADING
CATEGORICAL LIGHT TO MODERATE PRECIPITATION COVERAGE ACROSS THE
REGION THROUGH MIDDAY. MEANWHILE...1030 MB SFC HIGH PRES CONTINUES
TO LAY OVER TO THE N OF THE AREA...WITH CHILLY LOW LEVEL
THICKNESSES AND DRIER AIR PARKED ACROSS WRN NC. MODEL PROFILES FROM
ASHEVILLE TO W OF HICKORY TO NEAR BOONE SUPPORT SNOW AT ONSET
OVERNIGHT...WITH WET BULB PROFILES ISOTHERMAL NEAR ZERO. SOME DEGREE
OF WARM NOSING IS EXPECTED TO DEVELOP FRI MORNING...WITH A STEADY
TRANSITION TO SLEET THROUGH MID MORNING AND THEN BRIEF FREEZING RAIN
LINGERING ACROSS THE NRN BLUE RIDGE INTO THE AFTERNOON. PROFILES
SUPPORT MAINLY LIQUID ACROSS SC...NE GA...AND THE NC
PIEDMONT...ALTHOUGH BRIEF SLEET AT THE ONSET WILL BE POSSIBLE JUST
ABOUT ANYWHERE.
THE TRANSIENT NATURE OF THE WINTRY PTYPES ACROSS THE NC MTNS WILL
LIKELY WORK TO KEEP ANY ONE PTYPE FROM REACHING WARNING CRITERIA.
THE CURRENT ADVISORY SUITE REMAINS WELL PLACED...WITH LIGHT SNOW AND
ICE ACCUMULATIONS FRI...WITH A TRANSITION TO ADDITIONAL LIGHT NW
FLOW SNOW ACCUMULATIONS INTO FRI NIGHT. WILL KEEP TEMPS NEAR RAW
MODEL VALUES...WITH A BRIEFLY GUSTY NE FLOW POSSIBLE EAST OF THE
MTNS AS A BARRIER JET FORMS DESPITE THE WEAK DAMMING HIGH POSITION.
PRECIP RATES WILL LIKELY START TO SLACKEN FROM THE SW VERY LATE IN
THE DAY AS WEAK MID LEVEL DRYING BEGINS TO WORK BACK IN.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
AS OF 230 PM THURSDAY...THE SHORT TERM PICKS UP AT 00Z
SATURDAY...WITH MODELS IN GOOD AGREEMENT ON THE SFC LOW CENTERED
INVOF TALLAHASSEE FL...WITH A SHARP H5 TROF AXIS ACRS THE LWR MS
VALLEY. FRIDAY EVENING LOOKS LIKE A CONTINUED TRANSITION TO ALMOST
ALL RAIN ACRS THE CWFA...AS LLVL FLOW TURNS FROM SE TO SW...AND A
DRY SLOT PUNCHES INTO THE SRN APPALACHIANS FROM THE SW. TEMPS MAY BE
ABLE TO HOLD AROUND 30-32 ALONG THE ERN SLOPES OF THE NRN NC BLUE
RIDGE. HOWEVER...ADDITIONAL ICE ACCUMS SHUD BE VERY LIGHT...WITHIN A
LULL IN PRECIP. BY 12Z SAT...A DEFORMATION ZONE WITHIN THE MID LVL
TROF WILL ENTER THE NC MTNS...BRINGING FALLING MID LVL HEIGHTS (AND
SNOW LEVELS)...WHILE INCREASING THE POP. TAKING A BLEND OF THE
NAM/SREF WITH THE WPC QPF (THROWING OUT THE GFS)...I GET 1-2" OF
ADDITIONAL SNOW ACCUM MAINLY ABOVE 3500 FT SATURDAY MORNING. THE
DEFORMATION ZONE WILL TRANSLATE EAST QUICKLY...WITH POPS TAPERING
OFF BY MIDDAY. BY SATURDAY AFTN...NWLY 850 MB FLOW WILL
INCREASE...KEEPING A SLGT CHC TO LOW-END CHC OF SNOW SHWRS ALONG THE
TN/NC BORDER. GRADUAL CLEARING IS EXPECTED EAST OF THE MTNS. TEMPS
WILL HOVER IN THE 30S ACRS THE AREA FRIDAY NIGHT TO NEAR 40 IN THE
UPR SAVANNAH VALLEY...THEN WARM LITTLE ABOVE 3500 FT...BUT INTO THE
MID-UPR 40S ACRS THE PIEDMONT ON SATURDAY.
SATURDAY NIGHT AND SUNDAY...A BROAD H5 TROF WILL LINGER IN WAKE OF
THE SATURDAY TROF PASSAGE. THE CWFA WILL BE IN BETWEEN A NOREASTER
AFFECTING THE MID ATLANTIC/NEW ENGLAND...AND A CLIPPER THAT WILL BE
DIVING INTO THE WRN GREAT LAKES. ANOTHER VORT MAX WILL CROSS THE NC
MTNS SATURDAY NIGHT WITHIN THE LONGWAVE TROF. IT WILL HAVE LITTLE
MOISTURE TO WORK WITH...BUT THE NAM AND GFS BOTH SHOW A HUNDREDTH OR
TWO OF QPF RESPONSE ALONG THE TN/NC NWLY FLOW UPSLOPE AREAS. I
BUMPED UP POPS BACK TO CHC SATURDAY NIGHT FROM MADISON TO AVERY
COUNTY FOR SNOW SHWRS. LITTLE OR NO ACCUMS ARE EXPECTED. THE LLVL
FLOW WILL BACK TO W-SWLY ON SUNDAY...AND GUIDANCE IN GOOD AGREEMENT
ON A DRY DAY ACRS THE CWFA AHEAD OF THE APPROACHING CLIPPER SYSTEM.
TAKING A MODEL BLEND...I GET NEAR NORMAL TEMPS UNDER PARTLY CLOUDY
SKIES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM THU...LONGWAVE TROUGH PERSISTS OVER THE ERN CONUS THRU
THE MOST OF THE MEDIUM RANGE. THE UPPER PATTERN IS INITIALLY LOCKED
IN PLACE BY A REX BLOCK OVER THE WEST COAST...WHICH BREAKS DOWN
MONDAY. GLOBAL MODELS DIFFER IN HOW THE PATTERN SUBSEQUENTLY EVOLVES
OVER THE WEST BUT AGREE RIDGING WILL OCCUR OVER THE EAST BY WED
NIGHT. WHILE THE ERN TROUGH REMAINS IN PLACE...A SERIES OF CLIPPER-
LIKE SHORTWAVES WILL MOVE ACROSS OUR AREA. MEAN NWLY FLOW WILL
CONTINUE...SUGGESTING A CONTINUED FOCUS FOR PRECIP CHANCES ALONG THE
WRN FACING SLOPES OF THE NC MTNS. THE PASSING SHORTWAVES APPEAR
CAPABLE OF FORCING VERY LIGHT PRECIP OVER THE PIEDMONT...MAINLY THE
NC SIDE. DOWNSLOPING WILL BE WORKING AGAINST SAID FORCING AND ONLY
LOW POPS AND QPF WILL BE ADVERTISED THERE. IN THE MTNS...BLENDED QPF
FROM THE GLOBAL MODELS AND AN EXPECTATION OF PREDOMINANTLY SNOW AS A
PTYPE SUGGEST TOTALS GENERALLY 1-2 INCHES IN THE 12 HR PERIODS
SUNDAY NIGHT AND MONDAY. THIS MAY WARRANT A WINTER WX ADVY.
THE 22/12Z GFS CONTINUES TO EXHIBIT A COUPLE OF KEY DIFFERENCES FROM
THE CORRESPONDING GEM OR EC. THE FIRST IS IN THE WELL DEFINED
SHORTWAVE CROSSING THE AREA MONDAY...WHICH DOES NOT COME AS FAR SOUTH
ON THE GFS PROGS AND IS FOLLOWED BY A SECONDARY CHANNELED AREA OF
VORT. THE EC DEPICTS A MORE BROAD TROUGH WITH DISTINCT EDDIES DARTING
THROUGH WITHIN. THE EC BRINGS ANOTHER WAVE OF LIGHT QPF INTO THE AREA
TUESDAY AS A RESULT...WHEN TEMPS HAVE COOLED TO BECOME A LITTLE MORE
SUPPORTIVE OF WINTRY PRECIP. THE GEM LOOKS MORE LIKE THE EC THAN THE
GFS BUT DOES NOT RESPOND WITH QPF TUE. RUN-TO-RUN CONSISTENCY IS NOT
THAT GREAT FOR ANY OF THE MODELS WITH THE SMALLER SCALE WAVES AND
ASSOCIATED QPF. WITH THIS PACKAGE THE PIEDMONT POPS HAVE BEEN
EXPANDED SLIGHTLY THRU EARLY TUE ON ACCOUNT OF CONTINUED HINTS AT
PRECIP.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AT KCLT...MID-LEVEL CIGS WILL CONTINUE TO FILL IN AND GRADUALLY
LOWER...AS MOISTURE AND RISING MOTION INCREASE IN ADVANCE OF
DEVELOPING GULF COASTAL STORM SYSTEM. RAIN CHANCES WILL INCREASE BY
12Z. BY LATE MORNING...RAIN SHOULD BE ONGOING...WITH LOWERING CIGS
AND VISBY EXPECTED IN SATURATING LOW LEVEL AIR MASS. IFR CIGS AND AT
LEAST PERIODIC IFR VISBY CAN BE EXPECTED BY NOON...IF NOT A LITTLE
SOONER. ONCE CONDITIONS DETERIORATE...THEY WILL BE SLOW TO
RECOVER...AS A HYBRID COLD AIR DAMMING EVENT BECOMES ESTABLISHED
ACROSS THE REGION. RAIN IS EXPECTED TO BEGIN DIMINISHING BY THE END
OF THE PERIOD...BUT CIGS AND VISBY SHOULD REMAIN LOW IN PERSISTENT
COOL WEDGE. NE WINDS WILL PERSIST THROUGH THE PERIOD...GENERALLY
LIGHT EARLY THIS MORNING...BUT INCREASING TO 8-12 KTS BY AFTERNOON.
ELSEWHERE...CIGS AND PRECIP CHANCES WILL GRADUALLY INCREASE THROUGH
THE OVERNIGHT HOURS...WITH RAIN EXPECTED TO BEGIN IN EARNEST BY
AROUND SUNRISE AT MOST TERMINALS (A COUPLE OF HOURS LATER AT KHKY).
LOWERING CIGS AND VISBY ARE EXPECTED IN SATURATING LOW LEVEL AIR
MASS. IFR CIGS AND AT LEAST PERIODIC IFR VISBY CAN BE EXPECTED BY
LATE-MORNING AT MOST TERMINALS...IF NOT A LITTLE SOONER. ONCE
CONDITIONS DETERIORATE...THEY WILL BE SLOW TO RECOVER...AS A HYBRID
COLD AIR DAMMING EVENT BECOMES ESTABLISHED ACROSS THE REGION. RAIN
IS EXPECTED TO BEGIN DIMINISHING BY THE END OF THE PERIOD...BUT CIGS
AND VISBY SHOULD REMAIN LOW IN PERSISTENT COOL WEDGE. NE WINDS WILL
PERSIST THROUGH THE PERIOD (PRIMARILY SE AT KAVL)...GENERALLY LIGHT
EARLY THIS MORNING...BUT INCREASING TO 8-12 KTS BY AFTERNOON.
OUTLOOK...WHILE PRECIPITATION IS EXPECTED TO DIMINISH...
RESTRICTIONS SHOULD CONTINUE LATE FRIDAY NIGHT BEFORE DIMINISHING
FROM THE SW ON SAT. A SERIES OF CLIPPER SYSTEMS WILL BRING SNOW
CHANCES TO THE AREA EARLY IN THE WEEK...MAINLY TO THE MTNS NORTH AND
WEST OF KAVL.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% MED 63% MED 77% HIGH 81%
KGSP HIGH 100% HIGH 85% HIGH 85% HIGH 83%
KAVL HIGH 100% MED 71% HIGH 85% HIGH 83%
KHKY HIGH 100% MED 67% HIGH 81% MED 73%
KGMU HIGH 100% HIGH 85% HIGH 92% HIGH 83%
KAND HIGH 100% MED 75% MED 74% HIGH 83%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO NOON EST
SATURDAY FOR NCZ033-048>052-058-059-062>064-501-503-505.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG/JDL
SHORT TERM...ARK
LONG TERM...WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
753 PM CST SAT JAN 24 2015
.UPDATE...
NO CHANGES NEEDED THIS EVENING AS LOW TEMPERATURES REMAIN ON TRACK
UNDER CLEAR SKIES.
TVT
&&
.PREV DISCUSSION... /ISSUED 541 PM CST SAT JAN 24 2015/
UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION BELOW.
PREV DISCUSSION... /ISSUED 310 PM CST SAT JAN 24 2015/
DISCUSSION...21Z SURFACE ANALYSIS PLACES A 1028 MB RIDGE OF HIGH
PRESSURE OVER SOUTHERN TEXAS THIS AFTERNOON. THIS RIDGE OF HIGH
PRESSURE EXTENDS INTO THE LOWER MISSISSIPPI VALLEY THIS AFTERNOON
AND IS BRINGING SUNNY SKIES AND TEMPERATURES IN THE 50S AT MANY
LOCATIONS. RAIN CHANCES SUNDAY/SUNDAY NIGHT AND AGAIN FOR
WEDNESDAY NIGHT/THURSDAY IS THE FOCUS IN THIS AFTERNOON/S
FORECAST.
HIGH PRESSURE WILL GRADUALLY WEAKEN LATER TONIGHT AS A COLD FRONT
OVER THE UPPER MIDWEST DROPS SOUTH INTO THE MIDDLE/LOWER
MISSISSIPPI VALLEY/S BY SUNDAY. THIS FRONT ALONG WITH A CLOSED
UPPER LEVEL LOW WILL BRING CHANCES FOR RAIN SHOWERS TO THE MID
SOUTH WITH THE BEST CHANCES OCCURRING MAINLY ALONG AND NORTH OF
I-40 WHERE BETTER FORCING WILL EXIST. PRECIPITATION IS EXPECTED TO
TAPER OFF SUNDAY EVENING WITH HIGH PRESSURE RETURNING BACK TO THE
FORECAST AREA THROUGH NEXT WEDNESDAY. A TIGHT PRESSURE GRADIENT
WILL PRODUCE GUSTY NORTHWEST WINDS ACROSS THE AREA SUNDAY NIGHT.
LONG TERM MODELS INDICATE THE NEXT CHANCE FOR RAIN WILL COME
WEDNESDAY NIGHT INTO THURSDAY AS ANOTHER FRONT MOVES THROUGH THE
REGION. WENT WITH LOW END SLIGHT CHANCE POPS FOR THIS TIME FRAME
AS THERE ARE SOME SLIGHT DIFFERENCES IN AMOUNT OF MOISTURE
BETWEEN THE GFS/ECMWF LONG TERM MODELS.
CJC
.AVIATION...
00Z TAFS
VFR AND LIGHT SOUTHWEST WINDS TO PREVAIL AREAWIDE THIS EVENING.
LATEST HRRR AND NAM SOUNDINGS SHOWED A LOWER POTENTIAL FOR IFR
CIGS AT TUP. IF WINDS COMPLETELY DECOUPLE THERE... MAY SEE SOME
GROUND FOG LATE OVERNIGHT.
UPPER LEVEL WAVE ARRIVES SUNDAY. VFR SHOULD PREVAIL MOST AREAS...
OWING TO INITIALLY DRY LAYER BELOW FL150.
PWB
&&
.AVIATION...
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
541 PM CST SAT JAN 24 2015
.UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION... /ISSUED 310 PM CST SAT JAN 24 2015/
DISCUSSION...21Z SURFACE ANALYSIS PLACES A 1028 MB RIDGE OF HIGH
PRESSURE OVER SOUTHERN TEXAS THIS AFTERNOON. THIS RIDGE OF HIGH
PRESSURE EXTENDS INTO THE LOWER MISSISSIPPI VALLEY THIS AFTERNOON
AND IS BRINGING SUNNY SKIES AND TEMPERATURES IN THE 50S AT MANY
LOCATIONS. RAIN CHANCES SUNDAY/SUNDAY NIGHT AND AGAIN FOR
WEDNESDAY NIGHT/THURSDAY IS THE FOCUS IN THIS AFTERNOON/S
FORECAST.
HIGH PRESSURE WILL GRADUALLY WEAKEN LATER TONIGHT AS A COLD FRONT
OVER THE UPPER MIDWEST DROPS SOUTH INTO THE MIDDLE/LOWER
MISSISSIPPI VALLEY/S BY SUNDAY. THIS FRONT ALONG WITH A CLOSED
UPPER LEVEL LOW WILL BRING CHANCES FOR RAIN SHOWERS TO THE MID
SOUTH WITH THE BEST CHANCES OCCURRING MAINLY ALONG AND NORTH OF
I-40 WHERE BETTER FORCING WILL EXIST. PRECIPITATION IS EXPECTED TO
TAPER OFF SUNDAY EVENING WITH HIGH PRESSURE RETURNING BACK TO THE
FORECAST AREA THROUGH NEXT WEDNESDAY. A TIGHT PRESSURE GRADIENT
WILL PRODUCE GUSTY NORTHWEST WINDS ACROSS THE AREA SUNDAY NIGHT.
LONG TERM MODELS INDICATE THE NEXT CHANCE FOR RAIN WILL COME
WEDNESDAY NIGHT INTO THURSDAY AS ANOTHER FRONT MOVES THROUGH THE
REGION. WENT WITH LOW END SLIGHT CHANCE POPS FOR THIS TIME FRAME
AS THERE ARE SOME SLIGHT DIFFERENCES IN AMOUNT OF MOISTURE
BETWEEN THE GFS/ECMWF LONG TERM MODELS.
CJC
&&
.AVIATION...
00Z TAFS
VFR AND LIGHT SOUTHWEST WINDS TO PREVAIL AREAWIDE THIS EVENING.
LATEST HRRR AND NAM SOUNDINGS SHOWED A LOWER POTENTIAL FOR IFR
CIGS AT TUP. IF WINDS COMPLETELY DECOUPLE THERE... MAY SEE SOME
GROUND FOG LATE OVERNIGHT.
UPPER LEVEL WAVE ARRIVES SUNDAY. VFR SHOULD PREVAIL MOST AREAS...
OWING TO INITIALLY DRY LAYER BELOW FL150.
PWB
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1129 PM CST THU JAN 22 2015
.UPDATE...
06Z AVIATION UPDATE.
&&
.AVIATION...
CEILINGS ARE SLOWLY FALLING THIS EVENING...AND WILL CONTINUE TO DO
SO AS PRECIP WORKS ITS WAY INTO THE REGION FROM THE SOUTH. MVFR
CEILINGS SHOULD IMPACT KBNA AND KCSV FIRST AROUND 9Z TO 11Z...THEN
KCKV BY 11Z AS RAIN CHANCES MOVE IN. THERE IS A CHANCE FOR SOME
SLEET DURING THE EARLY ONSET OF RAIN CHANCES BEFORE 12Z AS WELL. SOME
GUIDANCE SUGGESTS THAT EVEN IFR CEILINGS WILL MOVE INTO ALL
TERMINALS BY LATE MORNING AS THE RAIN IS OVER MIDDLE TN...AND EVEN
LIFR AT KCSV BY LATE MORNING. KEPT KBNA AT LOW MVFR TOMORROW WITH
KCKV AT IFR AND KCSV NEAR LIFR FOR THE AFTERNOON. IT LOOKS LIKE
CEILINGS MAY COME UP A BIT DURING THE EVENING AS PRECIP MOVES OUT
OF THE REGION FROM WEST TO EAST...BUT SHOULD REMAIN BELOW VFR
UNTIL OVERNIGHT AND INTO SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 843 PM CST THU JAN 22 2015/
UPDATE...
LATEST SURFACE OBSERVATIONS SHOW TEMPERATURES IN THE UPPER 30S TO
AROUND 40 ACROSS THE FORECAST AREA WITH DEWPOINTS IN THE MID 20S
TO LOWER 30S. THESE TEMPS ARE ALREADY AT FORECAST LOWS ACROSS THE
SOUTH...AND HAVE GONE AHEAD AND LOWERED MINS FOR TONIGHT AREAWIDE
CLOSER TO OUR SUPERMODEL BLEND. RADAR IMAGERY SHOWS LIGHT TO
MODERATE RAIN CONTINUES JUST TO OUR SOUTH ACROSS NORTHERN
MS/AL...AND THERE HAVE BEEN SEVERAL REPORTS OF SLEET MIXING IN
WITH THE RAIN AT TIMES WHERE PRECIP HAS BEEN HEAVIER. BASED ON
THESE REPORTS ALONG WITH HRRR AND A LOOK AT LATEST FORECAST
SOUNDINGS...WILL ADD A CHANCE OF SLEET TO ZONES FOR TONIGHT AS
DRY AIR IN THE LOWER TROPOSPHERE MAY ALLOW FOR BRIEF PERIODS OF
SLEET...ESPECIALLY ACROSS THE COOLER NORTHERN ZONES. NO SLEET
ACCUM IS EXPECTED DUE TO ABOVE FREEZING TEMPS. THERMO PROFILES IN
THE NORTHWEST MID STATE ARE VERY CLOSE TO BEING A RAIN/SNOW MIX
FOR A BRIEF TIME FRIDAY MORNING PER 00Z NAM...BUT EXPECTED LIGHT
NATURE OF PRECIP SHOULD KEEP EVERYTHING RAIN/POSSIBLE SLEET.
REST OF FORECAST FOR THE FRIDAY/FRIDAY NIGHT PERIOD REMAINS
GENERALLY ON TRACK...WITH RAIN CONTINUING AREAWIDE INTO THE
AFTERNOON BEFORE A BRIEF LULL IN PRECIPITATION. MORE RAIN THEN
MOVES IN FRIDAY EVENING AS UPPER TROUGH AXIS MOVES ACROSS...WITH
CAA ALOFT ALLOWING FOR THE RAIN TO MIX WITH AND EVENTUALLY
CHANGEOVER TO SNOW FRIDAY NIGHT BEFORE ENDING SATURDAY MORNING. A
LOOK AT LATEST COBB SNOW TOTALS FOR THE NAM AND GFS CONTINUE TO
SUGGEST A DUSTING TO HALF INCH OF SNOW POSSIBLE FOR MUCH OF THE
MID STATE FRIDAY NIGHT...WITH HIGHEST AMOUNTS IN THE HIGHER
ELEVATIONS OF THE HIGHLAND RIM AND ON THE CUMBERLAND PLATEAU. ANY
SNOW WOULD MAINLY ACCUMULATE ON GRASSY AREAS AND ELEVATED SURFACES
DUE TO THE LOW SNOW RATIOS EXPECTED AND TEMPERATURES REMAINING
NEAR/ABOVE FREEZING...SO NO SIGNIFICANT IMPACTS TO TRAVEL ARE
ANTICIPATED WITH THIS EVENT. ANY SNOW THAT CAN ACCUMULATE WILL
MELT QUICKLY SATURDAY MORNING AS TEMPERATURES WARM WELL INTO THE
40S.
SHAMBURGER
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
06
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1020 PM CST THU JAN 22 2015
.DISCUSSION...SEE AVIATION DISCUSSION FOR 06Z TAFS. ALSO ADJUSTED
POPS FOR INCREASED ACTIVITY AND GOING AREAL COVERAGE RATHER THAN
CHANCE/SLIGHT CHANCE.
&&
.AVIATION...MVFR CONDITIONS WILL CONTINUE OVERNIGHT ALONG WITH AREAS
OF LIGHT RAIN. HAVE A TEMPO GROUP IN EACH TAF TO ADDRESS SLIGHTLY
HEAVIER RAINFALL LATER TONIGHT INTO EARLY FRI MORNING IN RESPONSE TO
THE UPPER LOW SWINGING ACROSS THE REGION. CONDITIONS WILL IMPROVE TO
VFR LEVELS THROUGH MID MORNING ON FRI FROM WEST TO EAST. MOD NLY
WINDS WITH GUSTS TO AROUND 25KT TONIGHT WILL CONTINUE INTO FRI
MORNING THEN WILL SUBSIDE BY FRI AFTERNOON. SHOULD SEE LIGHT
MAINLY NORTHERLY WINDS AFTER 24/00Z.
&&
.PREV DISCUSSION... /ISSUED 842 PM CST THU JAN 22 2015/
DISCUSSION...AREAS OF LIGHT TO MODERATE RAINFALL HAVE DEVELOPED
IN THE PAST HOUR NEAR THE SOUTHERN COASTAL COUNTIES. HRRR 4 KM HAS
BEEN FLUCTUATING A BIT WITH RAIN OVER THE AREA FROM THE LAST
COUPLE OF RUNS. LATEST RUN IS SHOWING SOME RAIN CONTINUING INTO
THE OVERNIGHT HOURS. THUS...AM GOING TO KEEP THE CHANCE POPS GOING
FOR TONIGHT. HOWEVER...AM GOING TO LOWER THEM JUST A TAD OVER THE
VICTORIA AREA TO 40 POPS. OTHERWISE...GFE FORECAST MONITOR IS
SHOWING TEMPERATURES AND DEW POINTS MUCH IN LINE WITH CURRENT
FORECAST (GREEN). AS A RESULT...WILL KEEP ON-GOING FORECAST GOING
CONCERNING TEMPS/WINDS/DEW POINTS SINCE FORECAST OVERALL IS IN
REALLY GOOD SHAPE.
MARINE...SCA SEEMS TO BE WORKING FINE. WILL LOWER POPS JUST A BIT
OVER THE GULF WATERS...AS EXPECT AREAS OF RAIN TO MAINLY STAY
INLAND. STILL CHANCE POPS FOR THE NEARSHORE AND BAYS. SEAS ALREADY
NEAR 10 FEET AT BOY019...AS IT SHOWS IN FORECAST. THUS...NO
OTHER CHANGES NEEDED AT THIS TIME BESIDES THE SLIGHT POP ADJUSTMENT.
PREV DISCUSSION... /ISSUED 521 PM CST THU JAN 22 2015/
DISCUSSION...SEE AVIATION DISCUSSION BELOW FOR THE 00Z TAFS.
AVIATION...MVFR CONDITIONS ARE EXPECTED TO PREVAIL OVERNIGHT
ALONG WITH ADDITIONAL -RA AS AN UPPER LEVEL LOW SWINGS ACROSS TX.
CONDITIONS ARE FCST TO IMPROVE AROUND MID MORNING FRI AS THE UPPER
LOW EXITS THE REGION AND DRIER AIR BEGINS TO FILTER INTO S TX. LRD
IS EXPECTED TO IMPROVE TO VFR INITIALLY THEN IMPROVING CONDITIONS
WILL SPREAD EAST THROUGH THE DAY.
PREV DISCUSSION... /ISSUED 253 PM CST THU JAN 22 2015/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...COLD FRONT HAS
PUSHED OFF THE MIDDLE TEXAS COAST WITH A COLD AIRMASS ALREADY
SETTLED INTO THE REGION WITH COLD AIR ADVECTION CONTINUING THROUGH
THE NIGHT AS BREEZY/WINDY NORTHERLY WINDS PERSIST. AREAS OF LIGHT
RAIN CONTINUE TO DRIFT ACROSS INLAND AREAS AS OF MID AFTERNOON BUT
SHOULD GRADUALLY DISSIPATE EARLY THIS EVENING. ADDITIONAL RAIN
/MAINLY LIGHT/ IS PROG TO DEVELOP OVERNIGHT AS MUCH OF THE CWA
BECOMES PLACED IN THE RRQ OF A 110KT H25 JET STREAK AND A MID
LEVEL TROUGH AXIS APPROACHES THE REGION. RAIN CHANCES WILL
DECREASE EARLY FRIDAY AS MID LEVEL TROUGH BEGINS TO SHIFT EAST AND
LLVL MOISTURE DECREASES. GRADUAL CLEARING MAY OCCUR FROM NW TO SE
TOMORROW AFTERNOON...BUT OVERALL AM EXPECTING A MOSTLY CLOUDY DAY.
CONTINUED COLD AIR ADVECTION AND CLOUD COVER WILL KEEP DAYTIME
TEMPS WELL BELOW NORMAL WITH SOME LOCATIONS ACROSS NE ZONES
STRUGGLING TO GET OUT OF THE 40S. SURFACE RIDGE AXIS EXTENDS INTO
S TX FRIDAY NIGHT RESULTING IN DRY LOW LEVEL AIRMASS AND LIGHT
WINDS...ALLOWING FOR STRONG RADIATIONAL COOLING WITH TEMPS
AREAWIDE LIKELY TO FALL INTO THE 30S.
LONG TERM...(SATURDAY THROUGH THURSDAY)...TROUGH AXIS WILL BE EAST
OF THE AREA ON SATURDAY...WITH DRIER AIR FILTERING INTO SOUTH TEXAS.
WINDS WILL ALSO BE RELAXING AS PRESSURE GRADIENT WEAKENS. COOLEST
DAY OF THE EXTENDED WILL SATURDAY BEHIND DEPARTING TROUGH. HIGHS
WILL ONLY BE IN THE LOWER/MIDDLE 60S. WARMING TREND WILL THEN
COMMENCE ON SUNDAY. UPPER LEVEL RIDGE WILL REMAIN THE MAIN WEATHER
FEATURE ACROSS SOUTH TEXAS FOR THE UPCOMING WEEK. THIS WILL LEAD TO
QUIET WEATHER OVER THE AREA AND TEMPERATURES ABOVE NORMAL FOR THE
END OF JANUARY. HIGHS WILL GENERALLY BE IN THE LOWER TO MIDDLE 70S
OVER INLAND LOCATIONS...WITH MID/UPPER 60S ALONG THE IMMEDIATE
COAST.
MARINE...AS OF MID AFTERNOON A COLD FRONT WAS MOVING EAST ACROSS
THE OFFSHORE WATERS WITH A STRONG OFFSHORE FLOW AND HAZARDOUS
SEAS DEVELOPING IN ITS WAKE. SMALL CRAFT ADVISORIES ARE IN EFFECT
FOR ALL MARINE AREAS TONIGHT INTO FRIDAY. CONDITIONS WILL
GRADUALLY IMPROVE FRIDAY NIGHT WITH PLEASANT MARINE CONDITIONS
CURRENTLY EXPECTED OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 45 52 34 64 43 / 30 20 10 0 10
VICTORIA 43 50 34 62 39 / 30 30 10 0 10
LAREDO 43 55 37 65 42 / 30 10 0 0 0
ALICE 44 53 35 65 41 / 30 20 0 0 10
ROCKPORT 45 53 39 62 45 / 30 20 10 0 10
COTULLA 42 56 34 64 41 / 40 20 0 0 0
KINGSVILLE 45 54 35 66 42 / 30 20 0 0 10
NAVY CORPUS 46 52 38 62 47 / 30 20 10 0 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST FRIDAY NIGHT FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST FRIDAY FOR THE FOLLOWING
ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR.
&&
$$
TE/81...AVIATION
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
837 PM CST SAT JAN 24 2015
.UPDATE...
00Z NAM CONTINUES THE TREND OF TAKING THE CLIPPER FARTHER SOUTH.
NAM HAS LESS SNOW...SO WILL TRIM FORECAST AMOUNTS EVEN
MORE...ALTHOUGH NOT QUITE AS MUCH AS THE LATEST HRRR WHICH KEEPS
ALMOST ALL SNOW SOUTH OF THE ILLINOIS BORDER. ALSO WITH NORTHEAST
WINDS EXPECT SOME LIGHT LAKE EFFECT SNOW SUNDAY. INVERSION LOWERS
TO 25 HUNDRED FEET SUNDAY AFTERNOON...SO LITTLE IN THE WAY OF
ACCUMULATIONS.
&&
.AVIATION/06Z TAFS/...
EXPECT MVFR CIGS/VSBYS SPREAD SOUTHEAST WITH AN AREA OF LIGHT SNOW
FROM THE UPSTREAM CLIPPER TYPE LOW. THE LOW SHOULD TRACK ACROSS
CENTRAL IOWA TO CENTRAL/SOUTHERN ILLINOIS SUNDAY MORNING. SOME
POCKETS OF IFR CONDITIONS EXPECTED. WEST WINDS WILL GRADUALLY
WEAKEN INTO TONIGHT...THEN BECOME GUSTY OUT OF THE NORTHEAST BY
12Z SUNDAY. THESE WINDS WILL LINGER ON SUNDAY...WITH GUSTS TO 25
KNOTS POSSIBLE. ALSO WITH NORTHEAST WINDS EXPECT SOME LIGHT LAKE
EFFECT SNOW SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 331 PM CST SAT JAN 24 2015/
TONIGHT AND SUNDAY...FORECAST CONFIDENCE IS HIGH.
EXPECT MIDDLE TO HIGH CLOUDS TO FILL BACK IN ACROSS THE FAR WESTERN
COUNTIES THAT HAVE SEEN SOME CLEARING THIS AFTERNOON. LOW CLOUDS
WILL THEN FILL IN THIS AREA LATER TONIGHT INTO SUNDAY. LOW CLOUDS
SHOULD REMAIN ACROSS THE REST OF THE AREA INTO SUNDAY.
MODELS ARE FINALLY IN DECENT AGREEMENT WITH THE TRACK OF THE SURFACE
LOW AND 500 MB SHORTWAVE TROUGH ACROSS THE REGION. THEY BRING IT
SOUTHEASTWARD FROM SOUTHWEST MINNESOTA TO FAR NORTHEAST MISSOURI
TONIGHT...THEN INTO CENTRAL KENTUCKY ON SUNDAY. THE BULK OF THE 500
MB SHORTWAVE TROUGH MISSES THE AREA TO THE SOUTHWEST DURING THIS
TIME.
ENOUGH LOW LEVEL Q VECTOR CONVERGENCE CROSSES THE AREA TO CONTINUE
THE HIGHER END POPS FOR LIGHT SNOW LATER TONIGHT INTO SUNDAY
MORNING. LOWERED SNOWFALL AMOUNTS A BIT ACROSS THE AREA...WITH THE
BEST UPWARD VERTICAL MOTION TO THE SOUTHWEST.
AMOUNTS OF 1/2 INCH TOWARD SHEBOYGAN...TO AROUND 1 INCH IN
MADISON/MILWAUKEE/KENOSHA...TO AROUND 2 INCHES IN DARLINGTON ARE
EXPECTED. NO LAKE ENHANCEMENT IS EXPECTED...AS DELTA T VALUES ARE
NOT FAVORABLE SUNDAY...WITH VERY DRY AIR ABOVE THE INVERSION
DEVELOPING DURING THE AFTERNOON. TEMPERATURES TONIGHT WILL DROP INTO
THE 20S IN MOST OF THE AREA...WITH NEARLY STEADY TEMPERATURES ON
SUNDAY.
SHORT TERM...SUNDAY NIGHT THROUGH TUESDAY.
SUNDAY NIGHT...FORECAST CONFIDENCE HIGH
THE 12Z 12KM NAM HAS DONE AWAY WITH THE LAKE-EFFECT POTENTIAL WITH
ONSHORE 1000-900MB CONVERGENCE DISSIPATING RAPIDLY EARLY SUNDAY
EVENING AS GRADIENT EASES WITH CLIPPER LOW MOVING AWAY TO THE
SOUTHEAST AND WEAK RIDGE OF HIGH PRESSURE BUILDING IN. 925 MB DIP TO
THEIR LOWEST POINT AROUND 06Z...THEN STEADY OUT AND BEGIN TO RISE
TOWARDS MORNING WITH DEVELOPING SW FLOW AHEAD OF NEXT SHORT WAVE.
SHOULD SEE LOWS OF 10 TO 15 AROUND MIDNIGHT...THEN REMAIN STEADY.
LAKESHORE LOCATIONS WILL SEE READINGS HOLD UP HIGHER WITH RELATIVELY
WARMER ONSHORE FLOW.
MONDAY AND MONDAY NIGHT...FORECAST CONFIDENCE MEDIUM
WARM AIR ADVECTION AHEAD OF NEXT SHORT WAVE IN THE NWLY FLOW BRINGS
SLIGHT CHANCES TO NWRN PORTIONS OF CWA MONDAY MORNING...AND
OVERSPREADS ALL OF SRN WI MONDAY AFTERNOON. TRACK OF WAVE AND
SURFACE LOW KEEP BETTER FORCING...DEEP LAYER Q-VECTOR
CONVERGENCE/FRONTOGENETIC RESPONSE...AND DEEP MOISTURE TO THE
NORTHEAST.
INITIAL PCPN SHOULD BE ALL LIGHT SNOW WITH A SATURATED DENDRITE
GROWTH ZONE...TOUGH AMOUNTS WILL BE LIMITED BY DRY AIR BELOW 5K
FT...THEN MID-LEVELS DRY OUT WITH THE LOWER LAYERS SATURATING...BUT
OUT OF THE DENDRITE GROWTH ZONE. EXPECT A TRANSITION TO FREEZING
RAIN WHEN CRYSTALS ARE LOST. NOT MUCH ICE ACCUMULATION WITH PCPN
DIMINISHING AS LOW SHEARS OUT AND IS ABSORBED BY DEEPENING EAST
COAST LOW...AND COLUMN DRIES EARLY MONDAY EVENING.
TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE HIGH.
A DRY PERIOD AS HIGH PRESSURE MOVES ACROSS THE REGION. LITTLE IN THE
WAY OF TEMPERATURE ADVECTION AS 925-850 MB BAROCLINIC ZONES REMAIN
PARALLEL TO THE FLOW. LOOKING FOR HIGHS IN THE MID 30S AND LOWS IN
THE LOW 20S WITH TEENS IN THE FAR NORTH.
LONG TERM...WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM
NEXT SYSTEM TO AFFECT REGION MOVES IN WEDNESDAY NIGHT AND THURSDAY
AS A NORTHERN STREAM SHORT WAVE MERGES WITH A WAVE THAT TRACKS FROM
THE SRN CALIFORNIA COAST TO THE CENTRAL PLAINS. MODELS IN VERY GOOD
AGREEMENT IN TAKING A BROAD LEE TROUGH IN THE PLAINS AND CONSOLIDATE
IT INTO A RAPIDLY DEEPENING SURFACE LOW OVER NRN HALF OF IL BY
THURSDAY MORNING. THERMAL STRUCTURE INDICATES SRN CWA WILL SEE A
RAIN SNOW MIX WITH MAINLY LIGHT SNOW NORTHERN HALF. QPF AMOUNTS ARE
LOW WITH QPF MAX STAYING SOUTH CLOSER TOT HE LOW CENTER.
MODELS DIFFER ON WHETHER OR NOT TO BRING A SHORT WAVE INTO THE
REGION SATURDAY. 12Z ECMWF BRINGS A WAVE IN SATURDAY
AFTERNOON/EVENING FOLLOWED BY SOME OF THE COLDEST AIR OF THE SEASON
WHILE GFS KEEPS THE WAVE OVER SRN CANADA AND DELAYS INTRUSION OF
ARCTIC AIR.
AVIATION/00Z TAFS/...
EXPECT IFR CEILINGS TO SPREAD EAST ACROSS TAF SITES BY EARLY THIS
EVENING. THESE CEILINGS WILL LINGER TONIGHT INTO SUNDAY...BECOMING
MVFR LATER IN THE DAY. WEST WINDS WILL GRADUALLY WEAKEN INTO
TONIGHT...THEN BECOME GUSTY OUT OF THE NORTHEAST BY 12Z SUNDAY.
THESE WINDS WILL LINGER ON SUNDAY...WITH GUSTS TO 25 KNOTS POSSIBLE.
LIGHT SNOW WITH 1 MILE VISIBILITIES WILL SPREAD INTO MADISON BY 09Z
SUNDAY...AND THE EASTERN SITES BY 11Z SUNDAY. THE LIGHT SNOW WILL
LINGER THROUGH MOST OF THE MORNING...ENDING BETWEEN 16Z TO 18Z
SUNDAY. SNOWFALL RATES OF 0.1 TO 0.2 INCHES PER HOUR ARE EXPECTED.
TOTAL AMOUNTS OF AROUND 1 INCH ARE EXPECTED.
MARINE...
SMALL CRAFT ADVISORY CONTINUES LATER TONIGHT INTO SUNDAY EVENING
ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN. A TIGHT PRESSURE
GRADIENT WILL DEVELOP DURING THIS TIME...RESULTING IN GUSTY
NORTHEAST WINDS. GUSTS TO 30 KNOTS ARE POSSIBLE AT TIMES...WITH HIGH
WAVES OF 4 TO 6 FEET. FREEZING SPRAY IS ANTICIPATED WITH THE
EXPECTED WINDS AND WAVES.
GUSTY WINDS...HIGH WAVES AND SOME FREEZING SPRAY ARE POSSIBLE
THURSDAY INTO THURSDAY NIGHT...AS LOW PRESSURE PASSES BY TO THE
SOUTH OF THE AREA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 3 AM SUNDAY TO MIDNIGHT CST SUNDAY
NIGHT FOR LMZ644>646.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM CST SUNDAY
FOR LMZ643.
&&
$$
UPDATE...HENTZ
TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD
SUNDAY NIGHT THROUGH SATURDAY...REM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
513 PM CST SAT JAN 24 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 250 PM CST SAT JAN 24 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SOUTHWARD
MOVING ARCTIC COLD FRONT REACHING THE U.P. BORDER EARLY THIS
AFTERNOON. BEHIND THIS FRONT IS A VERY COLD/DRY AIRMASS AS EVIDENT
BY TEMPS ONLY IN THE SINGLE DIGITS AND DEWPOINTS BELOW ZERO OVER ONTARIO.
THE FRONT IS MAINLY INACTIVE AT THE MOMENT. WEAK SHORTWAVE ACTIVITY
COMBINED WITH UPPER DIVERGENCE IS CONTRIBUTING TO SCATTERED SNOW
SHOWERS AND FLURRIES THAT ARE MOVING ACROSS NORTHWEST AND
NORTH-CENTRAL WISCONSIN. EXPECTATION IS THAT THESE LIGHT SNOW
SHOWERS WILL GRADUALLY DROP SOUTH INTO CENTRAL AND EAST-CENTRAL
WISCONSIN LATER THIS AFTERNOON. FARTHER WEST...A CLIPPER SYSTEM IS
DROPPING SOUTHEAST ACROSS THE NORTHERN PLAINS WITH A DECENT SWATH OF
SNOW OCCURRING OVER NORTH DAKOTA. SNOWFALL POTENTIAL ALONG THE
FRONT AND FROM THE CLIPPER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...AN ARCTIC COLD FRONT WILL BE DROPPING SOUTH ACROSS THE
AREA THIS EVENING WHILE A CLIPPER TRACKS SOUTHEAST ACROSS THE
CENTRAL PLAINS AND INTO THE CENTRAL MISSISSIPPI VALLEY. PERHAPS
COULD SEE A FEW FLURRIES ALONG THE FRONT OVER FAR NORTHERN WISCONSIN
EARLY THIS EVENING...BUT ANTICIPATING BETTER CHANCES OF SNOW TO
OCCUR ALONG THE FRONT AS IT MOVES INTO CENTRAL WISCONSIN AND THE FOX
VALLEY BY MID-EVENING. GUIDANCE IS INDICATING DECENT MID-LEVEL FGEN
DEVELOPING ALONG THE FRONT IN ADDITION TO INCREASING LARGE SCALE
FORCING AHEAD OF THE SHORTWAVE. AS A RESULT...KEPT LOW CHANCE
POPS IN THE FORECAST THERE. STILL ANTICIPATING A GLANCING BLOW FROM
THE CLIPPER SYSTEM AFTER MIDNIGHT...THOUGH THE LATEST RUNS OF
MESOMODELS SUGGEST THE SNOW WILL MISS THE FORECAST AREA ENTIRELY.
AREAS FROM WISC RAPIDS TO WAUTOMA COULD SEE UP TO A HALF INCH...BUT
AMOUNTS WILL BE LESS FARTHER NORTH. WITH THE PASSAGE OF THE
FRONT...NORTHEAST WINDS WILL BECOME GUSTY OVER THE FOX VALLEY AND
LAKESHORE. WOULD NOT BE SURPRISED TO SEE A FEW GUSTS UP TO 30 MPH.
LOWS FALLING INTO THE UPPER SINGLE DIGITS IN THE FAR NORTH...TO THE
LOWER 20S IN THE SOUTH.
SUNDAY...A SMALL CHANCE OF SNOW WILL LINGER FROM WAUTOMA TO
MANITOWOC EARLY IN THE MORNING...BUT ANY SNOW SHOULD BE DEPARTING
QUICKLY AS THE CLIPPER MOVES TOWARDS THE OHIO VALLEY. MEANWHILE
ARCTIC HIGH PRESSURE WILL BE BUILDING SOUTHEAST OVER LAKE SUPERIOR.
THIS ARCTIC HIGH WILL BRING A VERY DRY AIRMASS INTO THE NORTHERN
PART OF THE STATE (DEWPOINTS OVER ONTARIO ARE BELOW 0F). EVEN
THOUGH TEMPS WILL BE UNSTABLE OVER LAKE SUPERIOR AND
MICHIGAN...EXPECT THIS DRY AIR TO ERODE THE CLOUD COVER AS LAKE
EFFECT STREAMERS BECOME RETREAT CLOSER TO THE SHORELINES. THINK ITS
POSSIBLE TO SEE SOME SUN IN THE AFTERNOON AS A RESULT. TEMPS WILL
FALL BACK INTO THE MIDDLE TEENS TO LOWER 20S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 250 PM CST SAT JAN 24 2015
WEAKENING CLIPPER SYSTEM SHOULD BRING LIGHT SNOW FOR
MONDAY THROUGH MONDAY EVENING. AN INCH OR LESS LIKELY IN MOST PLACES.
A BETTER CHANCE OF ACCUMULATING SNOW WEDNESDAY NIGHT AND THURSDAY
AS A CLIPPER SYSTEM AND ONE MOVING EAST FROM THE CENTRAL PLAINS
PHASE JUST TO OUR SOUTH. SHOULD BE ABLE TO GET A FEW INCHES DESPITE
MEAGER MOISTURE. VERY COLD AIR LOOKS LIKELY EARLY NEXT WEEK. SUBZERO
HIGH TEMPERATURES AND WIND CHILLS OF 30 BELOW POSSIBLE NEXT MONDAY
AND TUESDAY IF GFS AND ECMWF FORECASTS ARE CORRECT.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 511 PM CST SAT JAN 24 2015
COLD FRONT WL DROP SWD ACRS THE REST OF THE AREA THIS
EVENING...FOLLOWED BY SOME SHSN AND FLURRIES...AND MVFR CIGS. FLOW
ACRS LAKES MICHIGAN/SUPERIOR WL KEEP MVFR CIGS IN PLACE FOR A
WHILE...BUT INCOMING AIR MASS IS VERY DRY...SO EXPECT CLDS TO
DISSIPATE TOMORROW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
457 PM CST FRI JAN 23 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
TROUGH MOVING TO THE EAST-SOUTHEAST OVER FAR NORTHWEST WISCONSIN AND
THE WESTERN UPPER PENINSULA. AHEAD OF THIS SHORTWAVE...A MID AND
UPPER LEVEL FRONT COMBINED WILL MID-LEVEL LAPSE RATES OF 6.5-7.0
C/KM ARE CONTRIBUTING TO A BAND OF LIGHT PRECIP. SURFACE OBS AND A
FEW REPORTS INDICATE THAT THE PTYPE IS MAINLY SNOW...OCCASIONALLY
MIXED WITH SLEET. THE LEADING EDGE OF THIS PRECIP BAND IS
FIGHTING DRY AIR...BUT PRECIP IS REACHING THE GROUND FROM MEDFORD TO
MARINETTE. THIS BAND OF PRECIP WILL CONTINUE TO MOVE SOUTHEAST AND
CLEAR THE FORECAST AREA EARLY THIS EVENING. EXPECTING LITTLE TO NO
ACCUMULATION WITH ANY SNOW...BUT IT WILL LIKELY BRIEFLY DROP
VSBYS TO 2SM IN SPOTS. BEHIND THE SHORTWAVE...AN AREA OF CLEARING
IS MOVING SOUTHEAST OVER CENTRAL MINNESOTA TO THE FAR WESTERN UPPER
PENINSULA. THEN ANOTHER AREA OF STRATUS OVER NORTHERN MINNESOTA IS
DIVING SOUTHEAST AND WILL REACH N-C WISCONSIN BETWEEN 21Z-00Z.
PRECIP AND SKY TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE SHORTWAVE AND MID-LEVEL FRONT WILL BE MOVING
SOUTHEAST ACROSS NORTHEAST AND EAST-CENTRAL WISCONSIN EARLY IN THE
EVENING. LEFT A SLIGHT CHANCE OF LIGHT SNOW IN THE FORECAST UNTIL
7PM WHEN THINK ANY PRECIP WILL HAVE EXITED THE AREA. BEHIND THE
FRONT...SKIES WILL EVENTUALLY BECOME MOSTLY CLEAR OR PARTLY CLOUDY
FOR A PERIOD THIS EVENING BEFORE LOW STRATUS OVER NORTHERN MINNESOTA
SPREADS SOUTHEAST ACROSS NORTHERN WISCONSIN. MODELS APPEAR TO BE
TOO AGGRESSIVE WITH LOW LEVEL MOISTURE...SO SLOWED DOWN THE ARRIVAL
OF THIS STRATUS. BUT ONCE IT MOVES IN...THINK OVERCAST CONDITIONS
WILL STICK AROUND FOR THE REST OF THE NIGHT. THE PREVIOUS FORECAST
INCLUDED A CHANCE OF FLURRIES AND FREEZING DRIZZLE IN THE SNOWBELT.
BUT LOOKING AT PROGGED SOUNDINGS...MOISTURE DEPTH IS SHALLOW BELOW
850MB SO AM SKEPTICAL THAT PRECIP WILL OCCUR. BUT DOES NOT TAKE
MUCH THIS TIME OF THE YEAR...SO LEFT IN THE FORECAST TO MATCH UP
WITH SURROUNDING OFFICES. LOWS IN THE MIDDLE TO UPPER 20S.
SATURDAY...SHALLOW ARCTIC COLD FRONT WILL BE DROPPING SOUTH ACROSS
LAKE SUPERIOR TO THE U.P. BORDER DURING THE AFTERNOON. AHEAD OF
THIS BOUNDARY...THE LOW STRATUS WILL BE HARD TO REMOVE ESPECIALLY
WITH MID AND HIGH CLOUDS MOVING OVERHEAD AHEAD OF THE NEXT CLIPPER.
PRECIPITATION AHEAD OF THE SHORTWAVE SHOULD REMAIN WELL WEST OF THE
REGION THROUGH THE AFTERNOON. MAY SEE A FEW FLURRIES OR VERY PATCHY
FREEZING DRIZZLE ACROSS N-C WISCONSIN WITH NW WINDS IN PLACE...BUT
NOT EXPECTING ANY ACCUMULATIONS. HIGH TEMPS MAINLY IN THE LOWER TO
MIDDLE 30S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
MEAN FLOW ALOFT IS EXPECTED TO REMAIN FROM THE NORTHWEST LATE THIS
WEEKEND AND THROUGHOUT THE UPCOMING WEEK. THE MAIN FOCUS OF THIS
FORECAST IS ON SATURDAY NIGHT THROUGH MONDAY NIGHT AS A COUPLE OF
CLIPPER SYSTEMS IMPACT THE AREA. THE AXIS OF HEAVIEST SNOW WITH
THE SATURDAY NIGHT/SUNDAY SYSTEM WILL BE TO OUR SOUTHWEST...CLOSER
TO THE SURFACE LOW AND BETTER UPPER LEVEL SUPPORT. THE 12Z GFS
ONLY HAD SMALL QPF IN PARTS OF MARATHON COUNTY AND WOOD COUNTY
06Z-12Z SUNDAY...OTHER MODELS GENERALLY HAD QPF ACROSS MOST OR ALL
OF THE FORECAST AREA. KEPT CLOSE TO WHAT SURROUNDING OFFICES HAD
ALONG OUR BORDERS AND WHAT THE MAJORITY OF THE MODELS HAD FOR POPS
AND QPF. THIS RESULTED IN A SMALLER CHANGE TO FORECAST SNOW
TOTALS THAN WPC GUIDANCE...WHICH HAD LESS THAN AN INCH EVEN IN
CENTRAL WISCONSIN...WOULD SUGGEST.
SNOW TOTALS ARE EVEN MORE UNCERTAIN WITH THE NEXT SYSTEM THAT IS
EXPECTED TO BRING SNOW TO THE AREA MONDAY INTO MONDAY NIGHT. WENT
NO HIGHER THAN CHANCE POPS WITH THE SYSTEM. ONCE IT DEPARTS THERE
COULD BE SOME LAKE EFFECT SNOW SHOWERS IN FAR NORTH CENTRAL
WISCONSIN ON TUESDAY. ANOTHER SYSTEM MAY IMPACT THE AREA ON
WEDNESDAY NIGHT/THURSDAY...BUT FORECASTER CONFIDENCE THIS FAR OUT
IS RATHER POOR.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 455 PM CST FRI JAN 23 2015
NO REAL CHG TO FCST REASONING FM PREVIOUS ISSUANCE. MVFR CIGS
STILL WIDESPREAD BACK TO THE NW...AND EXPECT THESE TO OVERSPREAD
THE AREA THIS EVENING. ONCE IN PLACE...THEY WL PROBABLY LINGER
THROUGH AT LEAST TOMORROW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......SKOWRONSKI
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
TROUGH MOVING TO THE EAST-SOUTHEAST OVER FAR NORTHWEST WISCONSIN AND
THE WESTERN UPPER PENINSULA. AHEAD OF THIS SHORTWAVE...A MID AND
UPPER LEVEL FRONT COMBINED WILL MID-LEVEL LAPSE RATES OF 6.5-7.0
C/KM ARE CONTRIBUTING TO A BAND OF LIGHT PRECIP. SURFACE OBS AND A
FEW REPORTS INDICATE THAT THE PTYPE IS MAINLY SNOW...OCCASIONALLY
MIXED WITH SLEET. THE LEADING EDGE OF THIS PRECIP BAND IS
FIGHTING DRY AIR...BUT PRECIP IS REACHING THE GROUND FROM MEDFORD TO
MARINETTE. THIS BAND OF PRECIP WILL CONTINUE TO MOVE SOUTHEAST AND
CLEAR THE FORECAST AREA EARLY THIS EVENING. EXPECTING LITTLE TO NO
ACCUMULATION WITH ANY SNOW...BUT IT WILL LIKELY BRIEFLY DROP
VSBYS TO 2SM IN SPOTS. BEHIND THE SHORTWAVE...AN AREA OF CLEARING
IS MOVING SOUTHEAST OVER CENTRAL MINNESOTA TO THE FAR WESTERN UPPER
PENINSULA. THEN ANOTHER AREA OF STRATUS OVER NORTHERN MINNESOTA IS
DIVING SOUTHEAST AND WILL REACH N-C WISCONSIN BETWEEN 21Z-00Z.
PRECIP AND SKY TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE SHORTWAVE AND MID-LEVEL FRONT WILL BE MOVING
SOUTHEAST ACROSS NORTHEAST AND EAST-CENTRAL WISCONSIN EARLY IN THE
EVENING. LEFT A SLIGHT CHANCE OF LIGHT SNOW IN THE FORECAST UNTIL
7PM WHEN THINK ANY PRECIP WILL HAVE EXITED THE AREA. BEHIND THE
FRONT...SKIES WILL EVENTUALLY BECOME MOSTLY CLEAR OR PARTLY CLOUDY
FOR A PERIOD THIS EVENING BEFORE LOW STRATUS OVER NORTHERN MINNESOTA
SPREADS SOUTHEAST ACROSS NORTHERN WISCONSIN. MODELS APPEAR TO BE
TOO AGGRESSIVE WITH LOW LEVEL MOISTURE...SO SLOWED DOWN THE ARRIVAL
OF THIS STRATUS. BUT ONCE IT MOVES IN...THINK OVERCAST CONDITIONS
WILL STICK AROUND FOR THE REST OF THE NIGHT. THE PREVIOUS FORECAST
INCLUDED A CHANCE OF FLURRIES AND FREEZING DRIZZLE IN THE SNOWBELT.
BUT LOOKING AT PROGGED SOUNDINGS...MOISTURE DEPTH IS SHALLOW BELOW
850MB SO AM SKEPTICAL THAT PRECIP WILL OCCUR. BUT DOES NOT TAKE
MUCH THIS TIME OF THE YEAR...SO LEFT IN THE FORECAST TO MATCH UP
WITH SURROUNDING OFFICES. LOWS IN THE MIDDLE TO UPPER 20S.
SATURDAY...SHALLOW ARCTIC COLD FRONT WILL BE DROPPING SOUTH ACROSS
LAKE SUPERIOR TO THE U.P. BORDER DURING THE AFTERNOON. AHEAD OF
THIS BOUNDARY...THE LOW STRATUS WILL BE HARD TO REMOVE ESPECIALLY
WITH MID AND HIGH CLOUDS MOVING OVERHEAD AHEAD OF THE NEXT CLIPPER.
PRECIPITATION AHEAD OF THE SHORTWAVE SHOULD REMAIN WELL WEST OF THE
REGION THROUGH THE AFTERNOON. MAY SEE A FEW FLURRIES OR VERY PATCHY
FREEZING DRIZZLE ACROSS N-C WISCONSIN WITH NW WINDS IN PLACE...BUT
NOT EXPECTING ANY ACCUMULATIONS. HIGH TEMPS MAINLY IN THE LOWER TO
MIDDLE 30S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
MEAN FLOW ALOFT IS EXPECTED TO REMAIN FROM THE NORTHWEST LATE THIS
WEEKEND AND THROUGHOUT THE UPCOMING WEEK. THE MAIN FOCUS OF THIS
FORECAST IS ON SATURDAY NIGHT THROUGH MONDAY NIGHT AS A COUPLE OF
CLIPPER SYSTEMS IMPACT THE AREA. THE AXIS OF HEAVIEST SNOW WITH
THE SATURDAY NIGHT/SUNDAY SYSTEM WILL BE TO OUR SOUTHWEST...CLOSER
TO THE SURFACE LOW AND BETTER UPPER LEVEL SUPPORT. THE 12Z GFS
ONLY HAD SMALL QPF IN PARTS OF MARATHON COUNTY AND WOOD COUNTY
06Z-12Z SUNDAY...OTHER MODELS GENERALLY HAD QPF ACROSS MOST OR ALL
OF THE FORECAST AREA. KEPT CLOSE TO WHAT SURROUNDING OFFICES HAD
ALONG OUR BORDERS AND WHAT THE MAJORITY OF THE MODELS HAD FOR POPS
AND QPF. THIS RESULTED IN A SMALLER CHANGE TO FORECAST SNOW
TOTALS THAN WPC GUIDANCE...WHICH HAD LESS THAN AN INCH EVEN IN
CENTRAL WISCONSIN...WOULD SUGGEST.
SNOW TOTALS ARE EVEN MORE UNCERTAIN WITH THE NEXT SYSTEM THAT IS
EXPECTED TO BRING SNOW TO THE AREA MONDAY INTO MONDAY NIGHT. WENT
NO HIGHER THAN CHANCE POPS WITH THE SYSTEM. ONCE IT DEPARTS THERE
COULD BE SOME LAKE EFFECT SNOW SHOWERS IN FAR NORTH CENTRAL
WISCONSIN ON TUESDAY. ANOTHER SYSTEM MAY IMPACT THE AREA ON
WEDNESDAY NIGHT/THURSDAY...BUT FORECASTER CONFIDENCE THIS FAR OUT
IS RATHER POOR.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1127 AM CST FRI JAN 23 2015
A BAND OF LIGHT SNOW...POSSIBLY MIXED WITH SLEET...WILL BE MOVING
ACROSS CENTRAL AND NORTHEAST WISCONSIN THIS AFTERNOON. VSBYS MAY
BRIEFLY FALL TO MVFR BUT AM NOT CONFIDENT TO INCLUDE IN TAFS AT THE
MOMENT. ANY LIGHT PRECIP WILL HAVE EXITED THE TAFS SITES BY
00Z...THEN MVFR STRATUS IS EXPECTED TO MOVE SOUTHEAST ACROSS THE TAF
SITES THIS EVENING. SOME UNCERTAINTY IN REGARDS TO HOW SOON THIS
STRATUS WILL ARRIVE AS THE LATEST MODEL RUNS ARE QUITE AGGRESSIVE
WITH THE FORWARD MOTION OF THE STRATUS WHICH DOES NOT QUITE MATCH
OBSERVATIONS. WILL INCLUDE A SHORT PERIOD OF SCT CONDITIONS BEFORE
THE MVFR STRATUS ARRIVES. ONCE IT DOES...BKN TO OVC CONDITIONS ARE
EXPECTED TO REMAIN THROUGH THE DURATION OF THE FORECAST.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 AM CST FRI JAN 23 2015
.UPDATE...
ISSUED AT 1145 AM CST FRI JAN 23 2015
DESPITE A WIDE SWATH OF WEAK ECHOES ON RADAR...VERY LITTLE IS REACHING
THE GROUND GIVEN VERY DRY NEAR SURFACE LAYER AND CLOUD BASES GENERALLY
5000 FT AGL OR HIGHER. A FEW FLURRIES HAVE BEEN REPORTED ACROSS
NORTHERN WI IN COLDER AIR MASS. FARTHER SOUTH ACROSS THE FORECAST
AREA...COULD STILL SEE SOME LIGHT DRIZZLE/RAIN THIS AFTERNOON...BUT
RISING AIR/GROUND TEMPERATURES TO ABOVE 32 DEGREES WILL LIMIT
FREEZING POTENTIAL. ALL SAID...WILL ALLOW WINTER WEATHER ADVISORY
TO EXPIRE AT NOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS FOR THE EARLY PART OF THE FORECAST IS ON THE
POTENTIAL FOR FREEZING RAIN AND SLEET THIS MORNING.
CURRENTLY...A NORTHEAST TO SOUTHWEST ORIENTED MID LEVEL SHORT WAVE
TROUGH IS DROPPING SOUTH INTO NORTHERN MINNESOTA WITH A BAND OF
LIGHT PRECIPITATION OUT AHEAD OF IT. AT THE SURFACE/LOW LEVELS...A
NORTH TO SOUTH ORIENTED WARM FRONT IS ADVANCING SOUTHEASTWARD AS
WELL ACROSS MINNESOTA WITH THIS WARM LAYER CAUSING SOME
PRECIPITATION TYPE ISSUES IN NORTHERN MINNESOTA. EVEN THOUGH
SURFACE TEMPERATURES HAVE CLIMBED ABOVE FREEZING...ROAD
TEMPERATURES ARE STILL BELOW FREEZING AND IS CAUSING SOME ICY
CONDITIONS. SIMILAR CONDITIONS ARE NOTED LOCALLY WITH ROAD SENSORS
SAYING ROAD TEMPERATURES ARE CURRENTLY IN THE UPPER 20S TO AROUND
30.
THE QUESTION LOCALLY IS WITH HOW MUCH OF THIS PRECIPITATION WILL
MAKE IT DOWN HERE AND HOW FAR SOUTHEAST WILL THE WARM LAYER MAKE
IT. 23.07Z RAP SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER IN THE
LOWEST 5-6KFT OF THE PROFILE IN MOST SITES FROM POINTS SOUTH OF
SOUTHEAST MINNESOTA GOING EAST THROUGH CENTRAL WISCONSIN. FURTHER
NORTH...HOWEVER...TOWARD NORTH CENTRAL WISCONSIN THE POTENTIAL IS
THERE FOR DEEPER SATURATION AND A HIGHER CHANCE FOR PRECIPITATION.
THE WARM LAYER APPEARS TO CREEP UP TOWARD 1 TO 3C ABOVE
FREEZING...SO THERE WILL LIKELY BE SOME MELTING OF ANY ICE/SNOW
THAT TRIES TO FALL THROUGH THE COLUMN. THE WARMER PART OF THE WARM
NOSE APPEARS TO DROP DOWN FROM FAR NORTHWEST WISCONSIN DOWN TO
SOUTHEAST MINNESOTA/NORTH CENTRAL IOWA THIS MORNING...SO THE MAIN
PRECIPITATION TYPE THERE WOULD BE RAIN...IF IT PRECIPITATES. SAY
THAT IT DOES OCCUR...THE QUESTION BECOMES WHAT ROAD TEMPERATURES
WILL DO THROUGH THE MORNING.
OVERALL CONFIDENCE IS HIGHEST IN TAYLOR COUNTY THAT SOME ISSUES
WILL OCCUR WITH FREEZING RAIN/SLEET...SO WILL ADD THEM TO THE
ADVISORY. SHOULD THE PRECIPITATION MAKE IT FURTHER SOUTH...THEN A
SOUTHWARD EXPANSION TO THE ADVISORY MAY BE NEEDED...BUT CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO DO THAT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SNOW AMOUNTS ON
SATURDAY NIGHT INTO SUNDAY AS A LOW PRESSURE SYSTEM DROPS DOWN
FROM SOUTHERN CANADA. CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BE
MOVING THROUGH IN THE SATURDAY NIGHT/SUNDAY TIME FRAME...BUT
CONFIDENCE IS RATHER LOW WITH THE TRACK OF THE SYSTEM. THE 23.00Z
ECMWF IS THE FURTHEST SOUTH WITH THE LEAST AMOUNT OF SNOW...THE
23.00Z NAM IS THE SLOWEST AND HAS THE NARROWEST BAND MOVING
THROUGH WEST CENTRAL WISCONSIN AND THE 23.00Z GFS IS SOMEWHERE IN
BETWEEN THESE TWO WITH THE MOST WIDESPREAD AND HEAVIEST SNOW. AT
THIS POINT...CAN ONLY TAKE THE MIDDLE OF THE ROAD WHICH ENDS UP
BEING CLOSE TO THE GFS PATH WITH LESS QPF. STILL...WITH SNOW
RATIOS OF AROUND 13:1 AND QPF OF AROUND A QUARTER OF AN
INCH...COULD SEE SOME 2 TO 4 INCH SNOWS FROM THIS QUICK MOVING
SYSTEM. INCREASED THE PRECIPITATION CHANCES FOR THE EVENT SINCE
IT IS LOOKING LIKE MOST OF THE REGION WILL SEE SOME SNOW...IT IS
JUST A MATTER OF HOW MUCH.
BEYOND THIS...ONLY MADE SOME ADJUSTMENTS TO THE WEDNESDAY HIGH
TEMPERATURE FORECAST FOR WHAT APPEARS TO BE A STRONG SOUTHERLY
FLOW DAY WITH A WARM AIR MASS MOVING IN FROM THE SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1145 AM CST FRI JAN 23 2015
VFR CONDITIONS EXPECTED AT BOTH TAF AIRFIELDS THROUGH THE
AFTERNOON. MAY EVEN SEE A FEW HOURS OF FULL SUN LATE AFTERNOON/
EARLY EVENING AS BACK EDGE OF MID-CLOUD DECK ACROSS CENTRAL MN IS
EXPECTED TO MOVE THROUGH UPPER MS RIVER VALLEY BEFORE THE NEXT
BATCH OF LOW STRATUS DROPS SOUTH FROM NORTHERN MN. DELAYED ONSET
OF THESE LOWER CEILINGS UNTIL 24.01Z AT KSRT AND 24.02Z AT KLSE.
THEREAFTER...MVFR/IFR CEILINGS WILL BE THE RULE THROUGH THE REST
OF THE TAF PERIOD. SOUTHWEST WIND WILL GRADUALLY DECREASE AND
SHIFT TO THE NORTHWEST BY THIS EVENING AND INTO THE OVERNIGHT.
LOOKING AHEAD...IFR CHANCES AND LIGHT SNOW INCREASE AT KRST/KLSE
AFTER 25.00Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
540 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS FOR THE EARLY PART OF THE FORECAST IS ON THE
POTENTIAL FOR FREEZING RAIN AND SLEET THIS MORNING.
CURRENTLY...A NORTHEAST TO SOUTHWEST ORIENTED MID LEVEL SHORT WAVE
TROUGH IS DROPPING SOUTH INTO NORTHERN MINNESOTA WITH A BAND OF
LIGHT PRECIPITATION OUT AHEAD OF IT. AT THE SURFACE/LOW LEVELS...A
NORTH TO SOUTH ORIENTED WARM FRONT IS ADVANCING SOUTHEASTWARD AS
WELL ACROSS MINNESOTA WITH THIS WARM LAYER CAUSING SOME
PRECIPITATION TYPE ISSUES IN NORTHERN MINNESOTA. EVEN THOUGH
SURFACE TEMPERATURES HAVE CLIMBED ABOVE FREEZING...ROAD
TEMPERATURES ARE STILL BELOW FREEZING AND IS CAUSING SOME ICY
CONDITIONS. SIMILAR CONDITIONS ARE NOTED LOCALLY WITH ROAD SENSORS
SAYING ROAD TEMPERATURES ARE CURRENTLY IN THE UPPER 20S TO AROUND
30.
THE QUESTION LOCALLY IS WITH HOW MUCH OF THIS PRECIPITATION WILL
MAKE IT DOWN HERE AND HOW FAR SOUTHEAST WILL THE WARM LAYER MAKE
IT. 23.07Z RAP SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER IN THE
LOWEST 5-6KFT OF THE PROFILE IN MOST SITES FROM POINTS SOUTH OF
SOUTHEAST MINNESOTA GOING EAST THROUGH CENTRAL WISCONSIN. FURTHER
NORTH...HOWEVER...TOWARD NORTH CENTRAL WISCONSIN THE POTENTIAL IS
THERE FOR DEEPER SATURATION AND A HIGHER CHANCE FOR PRECIPITATION.
THE WARM LAYER APPEARS TO CREEP UP TOWARD 1 TO 3C ABOVE
FREEZING...SO THERE WILL LIKELY BE SOME MELTING OF ANY ICE/SNOW
THAT TRIES TO FALL THROUGH THE COLUMN. THE WARMER PART OF THE WARM
NOSE APPEARS TO DROP DOWN FROM FAR NORTHWEST WISCONSIN DOWN TO
SOUTHEAST MINNESOTA/NORTH CENTRAL IOWA THIS MORNING...SO THE MAIN
PRECIPITATION TYPE THERE WOULD BE RAIN...IF IT PRECIPITATES. SAY
THAT IT DOES OCCUR...THE QUESTION BECOMES WHAT ROAD TEMPERATURES
WILL DO THROUGH THE MORNING.
OVERALL CONFIDENCE IS HIGHEST IN TAYLOR COUNTY THAT SOME ISSUES
WILL OCCUR WITH FREEZING RAIN/SLEET...SO WILL ADD THEM TO THE
ADVISORY. SHOULD THE PRECIPITATION MAKE IT FURTHER SOUTH...THEN A
SOUTHWARD EXPANSION TO THE ADVISORY MAY BE NEEDED...BUT CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO DO THAT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SNOW AMOUNTS ON
SATURDAY NIGHT INTO SUNDAY AS A LOW PRESSURE SYSTEM DROPS DOWN
FROM SOUTHERN CANADA. CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BE
MOVING THROUGH IN THE SATURDAY NIGHT/SUNDAY TIME FRAME...BUT
CONFIDENCE IS RATHER LOW WITH THE TRACK OF THE SYSTEM. THE 23.00Z
ECMWF IS THE FURTHEST SOUTH WITH THE LEAST AMOUNT OF SNOW...THE
23.00Z NAM IS THE SLOWEST AND HAS THE NARROWEST BAND MOVING
THROUGH WEST CENTRAL WISCONSIN AND THE 23.00Z GFS IS SOMEWHERE IN
BETWEEN THESE TWO WITH THE MOST WIDESPREAD AND HEAVIEST SNOW. AT
THIS POINT...CAN ONLY TAKE THE MIDDLE OF THE ROAD WHICH ENDS UP
BEING CLOSE TO THE GFS PATH WITH LESS QPF. STILL...WITH SNOW
RATIOS OF AROUND 13:1 AND QPF OF AROUND A QUARTER OF AN
INCH...COULD SEE SOME 2 TO 4 INCH SNOWS FROM THIS QUICK MOVING
SYSTEM. INCREASED THE PRECIPITATION CHANCES FOR THE EVENT SINCE
IT IS LOOKING LIKE MOST OF THE REGION WILL SEE SOME SNOW...IT IS
JUST A MATTER OF HOW MUCH.
BEYOND THIS...ONLY MADE SOME ADJUSTMENTS TO THE WEDNESDAY HIGH
TEMPERATURE FORECAST FOR WHAT APPEARS TO BE A STRONG SOUTHERLY
FLOW DAY WITH A WARM AIR MASS MOVING IN FROM THE SOUTH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 540 AM CST FRI JAN 23 2015
INCREASING SOUTHWEST LOW LEVEL FLOW HAS FINALLY PUSHED THE MVFR
CLOUD DECK EAST AND OUT OF THE TAF SITES. GENERALLY GOOD VFR
CONDITIONS EXPECTED TODAY...WITH MODERATE SOUTHWEST WINDS OF 10-
20KTS. A COLD FRONT WILL DROP SOUTH ACROSS THE AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. LOW LEVEL MOISTURE WILL ONCE AGAIN
INCREASE ACROSS THE AREA BEHIND THIS FRONT. MVFR CLOUD DECKS TO MOVE
INTO THE TAF SITES VERY LATE THIS AFTERNOON...THEN PERSIST THRU
TONIGHT. WITH DIURNAL COOLING...CLOUD HGTS EXPECTED TO DROP TO IFR
AT KRST BY MID EVENING. NORTHWEST WINDS 10-15KT ALSO SPREAD ACROSS
THE AREA BEHIND THE FRONT FOR TONIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
340 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS FOR THE EARLY PART OF THE FORECAST IS ON THE
POTENTIAL FOR FREEZING RAIN AND SLEET THIS MORNING.
CURRENTLY...A NORTHEAST TO SOUTHWEST ORIENTED MID LEVEL SHORT WAVE
TROUGH IS DROPPING SOUTH INTO NORTHERN MINNESOTA WITH A BAND OF
LIGHT PRECIPITATION OUT AHEAD OF IT. AT THE SURFACE/LOW LEVELS...A
NORTH TO SOUTH ORIENTED WARM FRONT IS ADVANCING SOUTHEASTWARD AS
WELL ACROSS MINNESOTA WITH THIS WARM LAYER CAUSING SOME
PRECIPITATION TYPE ISSUES IN NORTHERN MINNESOTA. EVEN THOUGH
SURFACE TEMPERATURES HAVE CLIMBED ABOVE FREEZING...ROAD
TEMPERATURES ARE STILL BELOW FREEZING AND IS CAUSING SOME ICY
CONDITIONS. SIMILAR CONDITIONS ARE NOTED LOCALLY WITH ROAD SENSORS
SAYING ROAD TEMPERATURES ARE CURRENTLY IN THE UPPER 20S TO AROUND
30.
THE QUESTION LOCALLY IS WITH HOW MUCH OF THIS PRECIPITATION WILL
MAKE IT DOWN HERE AND HOW FAR SOUTHEAST WILL THE WARM LAYER MAKE
IT. 23.07Z RAP SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER IN THE
LOWEST 5-6KFT OF THE PROFILE IN MOST SITES FROM POINTS SOUTH OF
SOUTHEAST MINNESOTA GOING EAST THROUGH CENTRAL WISCONSIN. FURTHER
NORTH...HOWEVER...TOWARD NORTH CENTRAL WISCONSIN THE POTENTIAL IS
THERE FOR DEEPER SATURATION AND A HIGHER CHANCE FOR PRECIPITATION.
THE WARM LAYER APPEARS TO CREEP UP TOWARD 1 TO 3C ABOVE
FREEZING...SO THERE WILL LIKELY BE SOME MELTING OF ANY ICE/SNOW
THAT TRIES TO FALL THROUGH THE COLUMN. THE WARMER PART OF THE WARM
NOSE APPEARS TO DROP DOWN FROM FAR NORTHWEST WISCONSIN DOWN TO
SOUTHEAST MINNESOTA/NORTH CENTRAL IOWA THIS MORNING...SO THE MAIN
PRECIPITATION TYPE THERE WOULD BE RAIN...IF IT PRECIPITATES. SAY
THAT IT DOES OCCUR...THE QUESTION BECOMES WHAT ROAD TEMPERATURES
WILL DO THROUGH THE MORNING.
OVERALL CONFIDENCE IS HIGHEST IN TAYLOR COUNTY THAT SOME ISSUES
WILL OCCUR WITH FREEZING RAIN/SLEET...SO WILL ADD THEM TO THE
ADVISORY. SHOULD THE PRECIPITATION MAKE IT FURTHER SOUTH...THEN A
SOUTHWARD EXPANSION TO THE ADVISORY MAY BE NEEDED...BUT CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO DO THAT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SNOW AMOUNTS ON
SATURDAY NIGHT INTO SUNDAY AS A LOW PRESSURE SYSTEM DROPS DOWN
FROM SOUTHERN CANADA. CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BE
MOVING THROUGH IN THE SATURDAY NIGHT/SUNDAY TIME FRAME...BUT
CONFIDENCE IS RATHER LOW WITH THE TRACK OF THE SYSTEM. THE 23.00Z
ECMWF IS THE FURTHEST SOUTH WITH THE LEAST AMOUNT OF SNOW...THE
23.00Z NAM IS THE SLOWEST AND HAS THE NARROWEST BAND MOVING
THROUGH WEST CENTRAL WISCONSIN AND THE 23.00Z GFS IS SOMEWHERE IN
BETWEEN THESE TWO WITH THE MOST WIDESPREAD AND HEAVIEST SNOW. AT
THIS POINT...CAN ONLY TAKE THE MIDDLE OF THE ROAD WHICH ENDS UP
BEING CLOSE TO THE GFS PATH WITH LESS QPF. STILL...WITH SNOW
RATIOS OF AROUND 13:1 AND QPF OF AROUND A QUARTER OF AN
INCH...COULD SEE SOME 2 TO 4 INCH SNOWS FROM THIS QUICK MOVING
SYSTEM. INCREASED THE PRECIPITATION CHANCES FOR THE EVENT SINCE
IT IS LOOKING LIKE MOST OF THE REGION WILL SEE SOME SNOW...IT IS
JUST A MATTER OF HOW MUCH.
BEYOND THIS...ONLY MADE SOME ADJUSTMENTS TO THE WEDNESDAY HIGH
TEMPERATURE FORECAST FOR WHAT APPEARS TO BE A STRONG SOUTHERLY
FLOW DAY WITH A WARM AIR MASS MOVING IN FROM THE SOUTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1118 PM CST THU JAN 22 2015
BREEZY SOUTH TO SOUTHWEST WINDS ARE HELPING TO PUSH THE
PERSISTENT IFR/MVFR STRATUS DECK OFF TO THE EAST. RST SHOULD CLEAR
WITHIN THE NEXT 1-2 HRS WITH LSE IN 3-4 HRS. VFR CONDITIONS SHOULD
THEN PREVAIL UNTIL LATE AFTERNOON WHEN A COLD FRONT ARRIVES. ANY
PRECIPITATION ASSOCIATED WITH THIS FRONT SHOULD STAY TO THE NORTH.
HOWEVER...PLAN ON ANOTHER LOW STRATUS DECK TO MOVE IN BEHIND THE
FRONT. CEILINGS SHOULD START OFF MVFR...THEN FALL TO IFR AT RST
DURING THE EVENING...AIDED BY COOLING TEMPERATURES. THIS STRATUS
DECK WILL LIKELY REMAIN IN PLACE THROUGH SATURDAY.
REGARDING THE WINDS...A TIGHT PRESSURE GRADIENT IN PLACE WILL KEEP
A 10-20 KT BREEZE GOING UNTIL THE COLD FRONT ARRIVES. GUSTS OF
20-30 KT ARE ALSO POSSIBLE EARLY THIS MORNING AT RST WITH A
STRONGER WIND CORE COMING THROUGH ALOFT. EXPECT THE WINDS TO SWING
AROUND TO THE WEST AND EVENTUALLY NORTHWEST WITH THE PASSAGE OF
THE COLD FRONT. SPEEDS SHOULD DIMINISH SLIGHTLY LATE IN THE
EVENING WITH LOSS OF DAYTIME HEATING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS ALBANY NY
1234 AM EST SUN JAN 25 2015
.SYNOPSIS...
BEHIND A DEPARTING COASTAL STORM...SOME LINGERING SNOW
SHOWERS OR PATCHY FREEZING DRIZZLE WILL OCCUR THIS EVENING. A COLD
FRONT WILL MOVE ACROSS THE REGION LATE TONIGHT WITH SOME ADDITIONAL
SNOW SHOWERS...MAINLY FOR NORTHWESTERN PARTS OF THE AREA. AN ARCTIC
AIR MASS MOVING IN BEHIND THIS FRONT WILL ALLOW FOR MUCH COLDER
TEMPERATURES ON SUNDAY. ANOTHER COASTAL STORM WITH ACCUMULATING SNOW
IS POSSIBLE DURING THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1225 AM EST...SNOW SHOWERS WERE MOVING ACROSS THE WESTERN
PORTION OF THE FA. THESE SNOW SHOWERS WILL TEND TO WEAKEN AS THEY
MOVE FARTHER EAST INTO DRIER AIR.
THE 3KM HRRR SHOWS THIS ACTIVITY WEAKENING AND DRYING UP AS IT
MOVES FURTHER EASTWARD...AND 00Z KALY SOUNDING WOULD SUGGEST DRY
AIR WOULD PROBABLY WIN OUT. STILL...WILL CONTINUE TO MONITOR AS IT
PROGRESSES FURTHER EASTWARD. WITH COLDER AIR AND DEEPENING
MOISTURE ALOFT ARRIVING AHEAD OF THE NEXT FRONTAL SYSTEM...PTYPE
WILL BE SNOW SHOWERS.
THE COLD FRONT LOCATED TO OUR NORTHWEST ACROSS THE EASTERN GREAT
LAKES ASSOCIATED WITH NORTHERN STREAM ENERGY WILL MOVE
SOUTHEASTWARD INTO THE AREA LATE TONIGHT. SCATTERED SNOW SHOWERS
WILL PRECEDE AND ACCOMPANY THE BOUNDARY AND SHORT WAVE FOR THE
ADIRONDACKS...WITH LITTLE ACTIVITY EXPECTED FURTHER SOUTH AND
EAST.
TEMPERATURES WILL DROP ONLY GRADUALLY TONIGHT AS THE COLD FRONT
APPROACHES...AND MAY WIND UP HOLDING STEADY FOR MANY LOCATIONS IN
THE MID TO UPPER 20S. FAR NORTHWESTERN AREAS MAY FALL LATE
TONIGHT INTO THE TEENS AS THE COLD FRONT PASSES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
THE PASSAGE OF THE COLD FRONT IS EXPECTED AROUND DAY BREAK ACROSS
THE NORTHWESTERN PORTION OF THE FORECAST AREA AND BEFORE MIDDAY
ACROSS THE SOUTHEAST. HIGHER PRESSURE WILL BEGIN TO BUILD IN BEHIND
THE BOUNDARY DURING THE AFTERNOON. THERE WILL BE LITTLE RECOVERY IN
TEMPERATURES SUNDAY WITH THE COLD AIR ADVECTION IN THE WAKE OF THE
BOUNDARY. IN ADDITION THE BRISK NORTHWESTERLY WINDS WILL MAKE IN
FEEL EVEN COLDER.
HIGH PRESSURE CENTERED TO OUR NORTH WILL PASS OVER THE REGION SUNDAY
NIGHT INTO MONDAY AS AN AREA OF LOW PRESSURE PASSES TO OUR SOUTH IN
ASSOCIATION WITH A VIGOROUS SHORT WAVE. THE SURFACE LOW IS THEN
EXPECTED TO MOVE OFF THE CAROLINA COAST ON MONDAY. HOWEVER ALOFT AN
UPPER LOW IS EXPECTED TO DEVELOP ALONG THE MID ATLANTIC COAST MONDAY
NIGHT AS THE SHORT WAVE ROTATES THROUGH THE BASE OF THE DEEP LONGWAVE
TROUGH OVER THE EASTERN UNITED STATES. THIS WILL RESULT IN FURTHER
DEVELOPMENT/DEEPENING OF THE SURFACE LOW OFF THE MID ATLANTIC COAST.
IT WILL BE COLD AND FAIR SUNDAY NIGHT AS THE RIDGE DOMINATES OUR
WEATHER. LOWS ARE FORECAST TO BE IN THE SINGLE DIGITS WITH BELOW
ZERO READINGS ACROSS THE NORTHWESTERN THIRD OF THE FORECAST AREA.
WINDS WILL BE LIGHT. TEMPERATURES MONDAY ARE EXPECTED TO RUN AROUND
10 DEGREES BELOW NORMAL.
AT THIS TIME IT APPEARS THE FORECAST AREA MAY BE ON THE NORTHERN
EDGE OF THE PRECIPITATION SHIELD MONDAY WITH GREATER AND MORE
WIDESPREAD CHANCES FOR SNOW MONDAY NIGHT AS THE SURFACE LOW
DEEPENS AND IS DRAWN UNDER THE UPPER LOW MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE LONG TERM PERIOD WILL START OFF ACTIVE...ALTHOUGH THE DEGREE OF
IMPACT IS STILL YET TO BE DETERMINED. IN ADDITION...RATHER COLD
WEATHER IS EXPECTED THROUGH THE ENTIRE LONG TERM PERIOD.
AS AN UPPER LEVEL DISTURBANCE DIVES OUT OF THE NORTHERN STREAM
TOWARDS THE EASTERN SEABOARD...A NEW AREA OF LOW PRESSURE WILL
DEVELOP OFF THE COAST AND RAPIDLY DEEPEN ON TUESDAY. THIS IS SHOWN
IN THE 12Z ECMWF...GGEM...GFS...NAM AND MOST MEMBERS OF THE 12Z
GEFS. THE UPPER LEVEL ENERGY WILL BECOME CUT OFF...ALLOWING FOR A
PROLONGED PERIOD OF PRECIP IN THE FORM OF SNOW TO OCCUR ACROSS MUCH
OF NEW ENGLAND. OUR REGION WILL BE ON THE WESTERN FRINGE OF THIS
SYSTEM...ALTHOUGH THE EXACT TRACK IS STILL FAR FROM CERTAIN. WHILE
SOME SNOW LOOKS TO OCCUR ON TUESDAY...AMOUNTS ARE STILL QUITE
UNCERTAIN...WITH THE BEST CHANCE ACROSS EASTERN PARTS OF THE AREA.
WHILE THE 12Z NAM/ECMWF BOTH HAD A LOT OF PRECIP OVER OUR AREA...THE
12Z GGEM/GFS AND 18Z NAM KEPT THE HEAVIER PRECIP TO OUR EAST. AT
THIS POINT...WILL FAVOR AREAS EAST OF THE HUDSON RIVER FOR THE MOST
SNOWFALL AND HIGHEST POPS FOR TUESDAY INTO TUESDAY NIGHT.
STILL...THERE IS POTENTIAL FOR THIS STORM TO TRACK CLOSER TO OUR
AREA AND BRING A SIGNIFICANT SNOWFALL TO THE ENTIRE CWA...AND THE
WITH THE UPPER LEVEL LOW BECOMING CUTOFF...THIS MAKES THE FORECAST
RATHER DIFFICULT AND PARTICULAR UNCERTAIN. WE WILL MENTION THIS
SYSTEM IN OUR HWO. TEMPS WILL CONTINUE TO BELOW NORMAL WITH AN
ARCTIC AIRMASS IN PLACE...WITH HIGHS ONLY IN THE TEENS AND 20S...AND
LOWS BETWEEN -10 AND 5.
BY WEDNESDAY...THE STORM WILL BE MOVING AWAY...BUT IT REMAIN COLD
AND BLUSTERY BEHIND THE SYSTEM. TEMPS WILL CONTINUE TO BE IN THE
TEENS AND 20S FOR WED...WITH SINGLE DIGITS FOR WED NIGHT. NO PRECIP
IS EXPECTED...WITH A PARTLY TO MOSTLY CLEAR SKY.
ANOTHER NORTHERN STREAM CLIPPER SYSTEM LOOK TO IMPACT THE REGION
SOMETIME BETWEEN THURSDAY AFTERNOON AND FRIDAY. A ROUND OF LIGHT
SNOW LOOKS TO SPREAD FROM WEST TO EAST ACROSS THE AREA...WITH SOME
ACCUMULATION POSSIBLE FOR ALL AREAS. TEMPS LOOK A LITTLE WARMER THAN
RECENT DAYS...WITH HIGHS IN THE 20S FOR THURS/FRI. OVERNIGHT LOWS ON
THURS NIGHT WILL BE IN THE MID TEENS TO MID 20S.
COLDER AIR WILL ARRIVE BEHIND THIS NORTHERN STREAM CLIPPER SYSTEM.
MIN ON FRI NIGHT WILL BE IN THE SINGLE DIGITS. IT WILL BE COLD AND
BLUSTERY FOR SATURDAY WITH A PARTLY CLOUDY SKY...AND HIGHS IN THE
TEENS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AN ARCTIC COLD FRONT WILL APPROACH FROM THE NORTHWEST TOWARD
DAYBREAK...AND PASS ACROSS THE TAF SITES SUNDAY MORNING. HIGH
PRESSURE WILL THEN BUILD ACROSS THE TAF SITES FROM THE NORTH FOR
LATER SUNDAY AND SUNDAY NIGHT.
ABUNDANT LOW LEVEL MOISTURE POOLING AHEAD OF THE INCOMING FRONT HAS
RESULTED IN AREAS OF MVFR CIGS...WITH EVEN SOME ISOLATED IFR CIGS
AT KPSF. WE EXPECT MAINLY MVFR CIGS TO PERSIST AT ALL TAF SITES
EXCEPT KPOU UNTIL THE FRONT PASSES BETWEEN 11Z-13Z/SUN.
ALSO...SOME SNOW SHOWERS/FLURRIES MAY REACH KGFL/KALB/KPSF...ESP AS
THE FRONT PASSES THROUGH. THIS COULD CREATE BRIEF REDUCTIONS OF
VSBYS INTO THE MVFR/IFR RANGE.
ONCE THE FRONT PASSES...VFR CONDITIONS ARE THEN EXPECTED THROUGH
AT LEAST 06Z/MON.
WEST WINDS WILL CONTINUE THROUGH DAYBREAK AT 5-10 KT...BUT MAY
OCCASIONALLY GUST INTO THE 15-20 KT RANGE AT KALB AND KPSF. AS THE
FRONT PASSES...WINDS WILL VEER SLIGHTLY INTO THE NORTHWEST TO
NORTH...AND INCREASE TO 10-15 KT FOR LATER SUNDAY MORNING INTO THE
AFTERNOON...WITH SOME GUSTS POSSIBLY REACHING INTO THE 20-25 KT
RANGE AT KALB AND KPSF. WINDS WILL DECREASE TO LESS THAN 8 KT
SHORTLY AFTER SUNSET.
OUTLOOK...
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
&&
.HYDROLOGY...
NO SIGNIFICANT HYDRO PROBLEMS ARE EXPECTED THROUGH EARLY NEXT WEEK.
THE PRECIPITATION THAT DOES OCCUR WILL BE IN THE FORM OF SNOW.
ICE WILL CONTINUE TO THICKEN ON RIVERS...STREAMS...CREEKS...LAKES
AND OTHER BODIES OF WATER.
THE EAGLE BRIDGE GAGE ON THE HOOSIC RIVER CONTINUES TO BE HAMPERED
BY ICE EFFECTS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/11
NEAR TERM...IAA/FRUGIS/11
SHORT TERM...IAA
LONG TERM...FRUGIS
AVIATION...FRUGIS/KL
HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1226 AM EST SUN JAN 25 2015
.SYNOPSIS...
BEHIND A DEPARTING COASTAL STORM...SOME LINGERING SNOW
SHOWERS OR PATCHY FREEZING DRIZZLE WILL OCCUR THIS EVENING. A COLD
FRONT WILL MOVE ACROSS THE REGION LATE TONIGHT WITH SOME ADDITIONAL
SNOW SHOWERS...MAINLY FOR NORTHWESTERN PARTS OF THE AREA. AN ARCTIC
AIR MASS MOVING IN BEHIND THIS FRONT WILL ALLOW FOR MUCH COLDER
TEMPERATURES ON SUNDAY. ANOTHER COASTAL STORM WITH ACCUMULATING SNOW
IS POSSIBLE DURING THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1225 AM EST...SNOW SHOWERS WERE MOVING ACROSS THE WESTERN
PORTION OF THE FA. THESE SNOW SHOWERS WILL TEND TO WEAKEN AS THEY
MOVE FARTHER EAST INTO DRIER AIR.
THE 3KM HRRR SHOWS THIS ACTIVITY WEAKENING AND DRYING UP AS IT
MOVES FURTHER EASTWARD...AND 00Z KALY SOUNDING WOULD SUGGEST DRY
AIR WOULD PROBABLY WIN OUT. STILL...WILL CONTINUE TO MONITOR AS IT
PROGRESSES FURTHER EASTWARD. WITH COLDER AIR AND DEEPENING
MOISTURE ALOFT ARRIVING AHEAD OF THE NEXT FRONTAL SYSTEM...PTYPE
WILL BE SNOW SHOWERS.
THE COLD FRONT LOCATED TO OUR NORTHWEST ACROSS THE EASTERN GREAT
LAKES ASSOCIATED WITH NORTHERN STREAM ENERGY WILL MOVE
SOUTHEASTWARD INTO THE AREA LATE TONIGHT. SCATTERED SNOW SHOWERS
WILL PRECEDE AND ACCOMPANY THE BOUNDARY AND SHORT WAVE FOR THE
ADIRONDACKS...WITH LITTLE ACTIVITY EXPECTED FURTHER SOUTH AND
EAST.
TEMPERATURES WILL DROP ONLY GRADUALLY TONIGHT AS THE COLD FRONT
APPROACHES...AND MAY WIND UP HOLDING STEADY FOR MANY LOCATIONS IN
THE MID TO UPPER 20S. FAR NORTHWESTERN AREAS MAY FALL LATE
TONIGHT INTO THE TEENS AS THE COLD FRONT PASSES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
THE PASSAGE OF THE COLD FRONT IS EXPECTED AROUND DAY BREAK ACROSS
THE NORTHWESTERN PORTION OF THE FORECAST AREA AND BEFORE MIDDAY
ACROSS THE SOUTHEAST. HIGHER PRESSURE WILL BEGIN TO BUILD IN BEHIND
THE BOUNDARY DURING THE AFTERNOON. THERE WILL BE LITTLE RECOVERY IN
TEMPERATURES SUNDAY WITH THE COLD AIR ADVECTION IN THE WAKE OF THE
BOUNDARY. IN ADDITION THE BRISK NORTHWESTERLY WINDS WILL MAKE IN
FEEL EVEN COLDER.
HIGH PRESSURE CENTERED TO OUR NORTH WILL PASS OVER THE REGION SUNDAY
NIGHT INTO MONDAY AS AN AREA OF LOW PRESSURE PASSES TO OUR SOUTH IN
ASSOCIATION WITH A VIGOROUS SHORT WAVE. THE SURFACE LOW IS THEN
EXPECTED TO MOVE OFF THE CAROLINA COAST ON MONDAY. HOWEVER ALOFT AN
UPPER LOW IS EXPECTED TO DEVELOP ALONG THE MID ATLANTIC COAST MONDAY
NIGHT AS THE SHORT WAVE ROTATES THROUGH THE BASE OF THE DEEP LONGWAVE
TROUGH OVER THE EASTERN UNITED STATES. THIS WILL RESULT IN FURTHER
DEVELOPMENT/DEEPENING OF THE SURFACE LOW OFF THE MID ATLANTIC COAST.
IT WILL BE COLD AND FAIR SUNDAY NIGHT AS THE RIDGE DOMINATES OUR
WEATHER. LOWS ARE FORECAST TO BE IN THE SINGLE DIGITS WITH BELOW
ZERO READINGS ACROSS THE NORTHWESTERN THIRD OF THE FORECAST AREA.
WINDS WILL BE LIGHT. TEMPERATURES MONDAY ARE EXPECTED TO RUN AROUND
10 DEGREES BELOW NORMAL.
AT THIS TIME IT APPEARS THE FORECAST AREA MAY BE ON THE NORTHERN
EDGE OF THE PRECIPITATION SHIELD MONDAY WITH GREATER AND MORE
WIDESPREAD CHANCES FOR SNOW MONDAY NIGHT AS THE SURFACE LOW
DEEPENS AND IS DRAWN UNDER THE UPPER LOW MONDAY NIGHT.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE LONG TERM PERIOD WILL START OFF ACTIVE...ALTHOUGH THE DEGREE OF
IMPACT IS STILL YET TO BE DETERMINED. IN ADDITION...RATHER COLD
WEATHER IS EXPECTED THROUGH THE ENTIRE LONG TERM PERIOD.
AS AN UPPER LEVEL DISTURBANCE DIVES OUT OF THE NORTHERN STREAM
TOWARDS THE EASTERN SEABOARD...A NEW AREA OF LOW PRESSURE WILL
DEVELOP OFF THE COAST AND RAPIDLY DEEPEN ON TUESDAY. THIS IS SHOWN
IN THE 12Z ECMWF...GGEM...GFS...NAM AND MOST MEMBERS OF THE 12Z
GEFS. THE UPPER LEVEL ENERGY WILL BECOME CUT OFF...ALLOWING FOR A
PROLONGED PERIOD OF PRECIP IN THE FORM OF SNOW TO OCCUR ACROSS MUCH
OF NEW ENGLAND. OUR REGION WILL BE ON THE WESTERN FRINGE OF THIS
SYSTEM...ALTHOUGH THE EXACT TRACK IS STILL FAR FROM CERTAIN. WHILE
SOME SNOW LOOKS TO OCCUR ON TUESDAY...AMOUNTS ARE STILL QUITE
UNCERTAIN...WITH THE BEST CHANCE ACROSS EASTERN PARTS OF THE AREA.
WHILE THE 12Z NAM/ECMWF BOTH HAD A LOT OF PRECIP OVER OUR AREA...THE
12Z GGEM/GFS AND 18Z NAM KEPT THE HEAVIER PRECIP TO OUR EAST. AT
THIS POINT...WILL FAVOR AREAS EAST OF THE HUDSON RIVER FOR THE MOST
SNOWFALL AND HIGHEST POPS FOR TUESDAY INTO TUESDAY NIGHT.
STILL...THERE IS POTENTIAL FOR THIS STORM TO TRACK CLOSER TO OUR
AREA AND BRING A SIGNIFICANT SNOWFALL TO THE ENTIRE CWA...AND THE
WITH THE UPPER LEVEL LOW BECOMING CUTOFF...THIS MAKES THE FORECAST
RATHER DIFFICULT AND PARTICULAR UNCERTAIN. WE WILL MENTION THIS
SYSTEM IN OUR HWO. TEMPS WILL CONTINUE TO BELOW NORMAL WITH AN
ARCTIC AIRMASS IN PLACE...WITH HIGHS ONLY IN THE TEENS AND 20S...AND
LOWS BETWEEN -10 AND 5.
BY WEDNESDAY...THE STORM WILL BE MOVING AWAY...BUT IT REMAIN COLD
AND BLUSTERY BEHIND THE SYSTEM. TEMPS WILL CONTINUE TO BE IN THE
TEENS AND 20S FOR WED...WITH SINGLE DIGITS FOR WED NIGHT. NO PRECIP
IS EXPECTED...WITH A PARTLY TO MOSTLY CLEAR SKY.
ANOTHER NORTHERN STREAM CLIPPER SYSTEM LOOK TO IMPACT THE REGION
SOMETIME BETWEEN THURSDAY AFTERNOON AND FRIDAY. A ROUND OF LIGHT
SNOW LOOKS TO SPREAD FROM WEST TO EAST ACROSS THE AREA...WITH SOME
ACCUMULATION POSSIBLE FOR ALL AREAS. TEMPS LOOK A LITTLE WARMER THAN
RECENT DAYS...WITH HIGHS IN THE 20S FOR THURS/FRI. OVERNIGHT LOWS ON
THURS NIGHT WILL BE IN THE MID TEENS TO MID 20S.
COLDER AIR WILL ARRIVE BEHIND THIS NORTHERN STREAM CLIPPER SYSTEM.
MIN ON FRI NIGHT WILL BE IN THE SINGLE DIGITS. IT WILL BE COLD AND
BLUSTERY FOR SATURDAY WITH A PARTLY CLOUDY SKY...AND HIGHS IN THE
TEENS.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS.
THE EXCEPTION WILL BE THIS EVENING...AS LINGERING LOW LEVEL
MOISTURE MAY ALLOW FOR A BRIEF PERIOD OF MVFR MIST/LOW
STRATUS...MAINLY FOR KGFL OR KPSF. OTHERWISE...ENOUGH OF A GRADIENT
THANKS TO AN APPROACHING COLD FRONT LATE TONIGHT SHOULD KEEP
THINGS MIXED ENOUGH TO PREVENT ANY MVFR/IFR LOW CLOUDS FROM
OCCURRING. OTHERWISE CIGS WILL BE BKN-OVC AT AROUND 5-6 KFT FOR
MOST OF THE NIGHT.
THE PASSAGE OF THE FRONT LOOKS TO OCCUR EITHER LATE TONIGHT OR
EARLY SUNDAY MORNING AFTER SUNRISE. THE WIND SHIFT WITH THIS
BOUNDARY WILL BE SUBTLE...DUE TO W-NW FLOW ALREADY IN PLACE BEHIND
THE DEPARTING COASTAL STORM. WINDS WILL BECOME MORE WESTERLY FOR
SUNDAY AT AROUND 10 KTS.
CLOUDS SHOULD DECREASE THROUGH THE DAY ON SUNDAY BEHIND THE ARCTIC
BOUNDARY...BECOMING NEARLY CLEAR IN MOST AREAS BY ABOUT MIDDAY.
LITTLE TO NO PRECIP IS EXPECTED WITH THE PASSAGE OF THE BOUNDARY
FOR VALLEY SITES DUE TO LIMITED MOISTURE.
OUTLOOK...
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SN.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
THURSDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SN.
&&
.HYDROLOGY...
NO SIGNIFICANT HYDRO PROBLEMS ARE EXPECTED THROUGH EARLY NEXT WEEK.
THE PRECIPITATION THAT DOES OCCUR WILL BE IN THE FORM OF SNOW.
ICE WILL CONTINUE TO THICKEN ON RIVERS...STREAMS...CREEKS...LAKES
AND OTHER BODIES OF WATER.
THE EAGLE BRIDGE GAGE ON THE HOOSIC RIVER CONTINUES TO BE HAMPERED
BY ICE EFFECTS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/11
NEAR TERM...IAA/FRUGIS/11
SHORT TERM...IAA
LONG TERM...FRUGIS
AVIATION...FRUGIS
HYDROLOGY...IAA
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1142 PM CST SAT JAN 24 2015
.UPDATE...
900 PM CST
EVENING UPDATE...
HAVE UPDATED GRIDS TO REFLECT MUCH LOWER SNOWFALL AMOUNTS ON SUNDAY
TO THE NORTH OF INTERSTATE 80 AND ALSO SLOWED ARRIVAL OF
PRECIPITATION MAINLY TO EARLY TO MID SUNDAY MORNING. RADAR...SURFACE
ANALYSIS AND SATELLITE TRENDS SUPPORT THE NEW 00Z GUIDANCE AND
LATEST HIGHER RESOLUTION GUIDANCE ROLLING IN DIGGING THE 500 MB WAVE
FARTHER SOUTHWEST AND ASSOCIATED SURFACE LOW FARTHER SOUTHWEST AND
THEN SOUTH OF THE CWA. NOW LOOKING AT GENERALLY AROUND A FEW TENTHS
TO UP TO AN INCH NORTH OF INTERSTATE 88...ONE TO TWO INCHES BETWEEN
I-88 AND I-80 AND ONE TO THREE INCHES SOUTH OF INTERSTATE 80. IF THE
FARTHER SOUTH TREND BECOMES MORE AGGRESSIVE AS THE SYSTEM APPROACHES
SUNDAY...THEN EVEN THESE AMOUNTS COULD END UP BEING TOO HIGH.
NAM/WRF AND OTHER HIGHER-RES GUIDANCE CONTINUES TO HINT AT LAKE
ENHANCEMENT DURING THE DAY SUNDAY INTO THE AFTERNOON INTO PARTS OF
NORTHEAST IL AND NW IN...BUT UNLESS FRICTIONAL CONVERGENCE CAN
ENHANCE RATES A BIT...THE THERMODYNAMICS AND INVERSION HEIGHTS ARE
VERY MARGINAL TO ACTUALLY ADD MUCH TO SNOW TOTALS.
REGARDING THE MIXED PRECIPITATION IN THE SOUTHERN CWA...THE
SOUTHWARD TREND AND DELAYED TIMING OF THE SYSTEM SHOULD ALLOW FOR
COLDER AIR TO BLEED SOUTHWARD AND SUPPRESS THE MIXING ZONE SOUTHWARD
FROM THE PREVIOUS FORECAST. ANY WINTRY MIX/RAIN SNOW MIX IN THE FAR
SOUTHERN CWA WILL LIKELY TRANSITION TO SNOW BY MID DAY/EARLY
AFTERNOON.
UPDATED ZONES WILL BE SENT SHORTLY.
RC/KREIN
&&
.SHORT TERM...
250 PM CST
THROUGH SUNDAY...
MAIN FORECAST CONCERN WILL BE PASSAGE OF A CLIPPER SYSTEM ACROSS THE
MIDWEST BRINGING ACCUMULATING SNOWFALL AND FOR SOME AREAS A WINTRY
MIX OF PRECIPITATION. CLOUD COVER WILL CONTINUE TO INCREASE THE
REMAINDER OF THE TODAY AS THE LOW DIVES ACROSS THE DAKOTAS INTO
MINNESOTA. MODELS ARE IN DECENT AGREEMENT TRACKING THE SURFACE LOW
ACROSS FAR NE MO LATE TONIGHT INTO DOWNSTATE IL BY SUNDAY AFTERNOON.
1000MB-700MB LAYER MAX WETBULBS ARE UP TO 2C SOUTH OF THE I-80
CORRIDOR THROUGH LATE MORNING/EARLY AFTERNOON SUNDAY...THEN START TO
FALL QUICKLY FROM THE NORTH THROUGH THE AFTERNOON HOURS. WITH THAT
IN MIND...THINK THAT PRECIP WILL BEGIN AS PRIMARILY SNOW NORTH OF
THE I-80 CORRIDOR WITH RAIN/SLEET TO THE SOUTH...EVENTUALLY CHANGING
OVER TO ALL SNOW. MODELS IN GENERAL HAVE THE AXIS OF HIGHEST QPF
SOUTH OF I-80...BUT WITH WARMER TEMPERATURES...IT APPEARS THE
HIGHEST SNOWFALL MAY OCCUR A LITTLE FARTHER NORTH. DID BUMP UP SNOW
TOTALS ACROSS PORTIONS OF THE CHICAGO METRO WHERE MODELS CONTINUE TO
ADVERTISE AN INCREASE IN THE LOW LEVEL LAPSE RATES AS WINDS TURN NE
OFF LAKE MICHIGAN WITH LAKE ENHANCEMENT APPEARING AT LEAST POSSIBLE.
NAM AND REGIONAL GEM GUIDANCE BOTH SHOW A SLIGHT MAX IN THE QPF
VALUES OVER THE AREA AND HAVE BEEN CONSISTENTLY ADVERTISING A BUMP IN
THE LOW LEVEL OMEGA STARTING LATE MORNING INTO THE AFTERNOON.
FORECAST SNOW TOTALS FOR THIS EVENT WILL BE 1-3 INCHES WEST OF A
WAUKEGAN TO STREATOR LINE...AND 2-4 INCHES EAST. WILL HAVE TO
MONITOR THE MESOSCALE BANDING THREAT FOR SOME LOCALLY HIGHER
AMOUNTS. NAM GUIDANCE IN PARTICULAR WAS HINTING AT AN AREA OF LOW
LEVEL FGEN DEVELOPING FOR EAST CENTRAL IL AND NORTHWEST
INDIANA...BUT LAPSE RATES UPSTAIRS ARENT OVERLY IMPRESSIVE IN THE
LATEST MODELS RUNS. ALSO SURFACE LOW SLOWLY FILLING AS IT MOVES
TOWARDS THE OHIO VALLEY WILL ALSO BE A LIMITING FACTOR. WILL ISSUE
AN UPDATED SPS THIS AFTERNOON FOR THE SNOWFALL. AS MENTIONED...STILL
CANNOT RULE OUT SOME LOCALLY HIGHER AMOUNTS THAT MIGHT REQUIRE AN
ADVISORY HOWEVER DONT HAVE MUCH CONFIDENCE WHERE OR EVEN IF THIS
WOULD OCCUR.
WINDS WILL START TO RAMP UP FROM EARLY MORNING ON OUT OF THE
NORTHEAST AS A TIGHT GRADIENT SWEEPS ACROSS THE REGION ON THE BACK
SIDE OF THE LOW. NORTHEAST WINDS ARE EXPECTED TO GUST 30-35 MPH AT
TIMES ACROSS THE AREA. THESE MODERATELY STRONG NORTHEAST WINDS OVER
LAKE MICHIGAN WILL DRIVE 8-11 FOOT WAVES INTO THE NEARSHORE WATERS
AND SOME OF THESE WAVES MAY RESULT IN SOME MINOR LAKE SHORE FLOODING
TO EXPOSED AREAS. IN ADDITION...BLOWING SNOW MAY BECOME A PROBLEM
ESPECIALLY IN OPEN AREAS. WETTER THAN AVERAGE SNOW...PARTICULARLY
SOUTH OF I-80 MAY HELP LIMIT THE BLOWING SNOW SOME.
DEUBELBEISS
&&
.LONG TERM...
SUNDAY NIGHT THROUGH SATURDAY...
250 PM...FORECAST CONCERNS INCLUDE A CHANCE OF LIGHT SNOW MONDAY
AFTERNOON INTO MONDAY NIGHT AND THEN THE POTENTIAL FOR A WINTRY
MIX WEDNESDAY NIGHT.
LIGHT SNOW WILL BE ENDING ACROSS THE SOUTHEAST CWA SUNDAY EVENING
AS NORTHEAST WINDS STEADILY DIMINISH SUNDAY EVENING. LAKE EFFECT
CLOUDS AND PERHAPS A FEW FLURRIES ARE POSSIBLE SUNDAY EVENING. LOWS
BY MONDAY MORNING WILL DIP INTO THE TEENS MOST LOCATIONS BUT AS A
WEAK RIDGE PASSES ACROSS THE AREA AND WINDS BECOME LIGHT OR CALM...
LOWS COULD BE SEVERAL DEGREES COLDER DEPENDING ON CLOUD COVER.
ANOTHER WEAK CLIPPER SYSTEM MOVES SOUTHEAST ACROSS THE WESTERN
LAKES MONDAY AFTERNOON INTO MONDAY NIGHT AS IT SLOWLY BEGINS TO
WEAKEN. MODELS VARY SOME ON TIMING AND PRECIP ARRIVAL. A CONSENSUS
WOULD HAVE THE ARRIVAL DURING MONDAY AFTERNOON. INITIALLY THE
SATURATION IS DEEP ENOUGH THAT PRECIP SHOULD BEGIN AS LIGHT SNOW.
BUT INTO THE EVENING...MID LEVELS BEGIN TO DRY OUT SOME AND PRECIP
COULD TRANSITION MORE TO A LIGHT SNOW MIXED WITH OR JUST FREEZING
DRIZZLE. FAIRLY LOW CONFIDENCE AT THIS POINT...SO MAINTAINED JUST
LIGHT SNOW FOR THE ENTIRE DURATION FOR NOW.
PROGRESSIVE PATTERN BRINGS ANOTHER RIDGE OF HIGH PRESSURE ACROSS
THE REGION TUESDAY NIGHT INTO WEDNESDAY AND THEN ANOTHER STORM
SYSTEM WEDNESDAY NIGHT INTO THURSDAY MORNING. MODELS CURRENTLY IN
DECENT AGREEMENT WITH THE TRACK OF THIS LOW GENERALLY RIGHT ACROSS
THE CWA EARLY THURSDAY MORNING. WITH THIS TRACK...TEMPS LIKELY TO
REMAIN FAIRLY STEADY IN THE LOWER/MID 30S WEDNESDAY NIGHT AND
THERMAL PROFILES WOULD SUGGEST PRECIP WOULD BE MAINLY RAIN OR
PERHAPS FREEZING RAIN...IF SURFACE TEMPS REMAINED BELOW FREEZING.
AND ALSO COULD BE SOME SNOW IF THE LOW WERE TO SPEED UP AND/OR
TRACK FURTHER SOUTH. THUS DID NOT GET TOO SPECIFIC WITH PRECIP
TYPE WEDNESDAY NIGHT INTO THURSDAY BUT A WINTRY MIX IS POSSIBLE.
CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR/PATCHY IFR CIGS DEVELOPING PRE-DAWN.
* NORTHEAST WINDS INCREASING QUICKLY TOWARD SUNRISE...AND GUST
NEAR 30 KT AT TIMES LATE MORNING AND AFTERNOON.
* SNOW DEVELOPING EARLY-MID MORNING...WITH MVFR VSBY LIKELY AND
IFR AND SOME ACCUMULATION PROBABLE THROUGH MIDDAY BEFORE
TAPERING TO LIGHT SNOW SHOWERS OR FLURRIES EARLY THIS AFTERNOON.
* MVFR CIGS THIS AFTERNOON INTO THIS EVENING.
RATZER
//DISCUSSION...UPDATED 06Z...
LOW PRESSURE OVER CENTRAL IOWA WILL MOVE SOUTHEAST ACROSS
NORTHEAST MISSOURI AND INTO SOUTHERN ILLINOIS TODAY. NORTHEAST
WINDS WILL INCREASE QUICKLY TOWARD MORNING AS THE SURFACE PRESSURE
GRADIENT TIGHTENS IN RESPONSE TO THE RAPIDLY MOVING LOW PRESSURE
SYSTEM...MAKING FOR WINDY CONDITIONS WITH SUSTAINED SPEEDS 15-20
KT AND GUSTS 25-30 KT DURING THE LATE MORNING AND AFTERNOON HOURS.
WINDS WILL GRADUALLY DIMINISH TONIGHT AS WEAK HIGH PRESSURE
APPROACHES BY MONDAY MORNING.
AN EXTENSIVE AREA OF MVFR AND PATCHY IFR STRATUS OVER
MICHIGAN/WISCONSIN AND LAKE MICHIGAN IS EXPECTED TO SPREAD BACK
ACROSS THE TERMINALS EARLY THIS MORNING AS NORTHEAST WINDS
INCREASE. SNOW CURRENTLY DEPICTED BY RADAR RETURNS OVER SOUTHERN
MINNESOTA AND NORTHERN IOWA WILL SPREAD SOUTHEAST INTO THE REGION
THIS MORNING...WITH THE BULK OF THE HEAVIER SNOW EXPECTED OFF TO
THE SOUTHWEST OF THE TERMINALS. STILL...THE MID-MORNING THROUGH
NOON HOURS SHOULD SEE THE GREATEST PROBABILITY OF MINOR
ACCUMULATIONS AND MVFR/IFR VISIBILITY IN LIGHT SNOW. SNOW SHOULD
TAPER TO LIGHT SNOW SHOWERS AND FLURRIES THIS AFTERNOON.
MVFR STRATOCU LOOKS TO LINGER INTO TONIGHT...THOUGH SHOULD BECOME
THINNER WITH TIME AS DRIER AIR IS DRAWN IN FROM THE NORTHEAST.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM IN CIG TRENDS EARLY THIS MORNING AND IN SNOW
TIMING/IMPACT.
* HIGH IN WIND TRENDS.
* MEDIUM IN CIGS BEYOND THIS EVENING.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SLIGHT CHANCE -SN IN THE AFTERNOON. MVFR POSSIBLE.
TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MAINLY VFR DURING THE DAY THEN CHANCE OF -RASN AND
MVFR/IFR AT NIGHT.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF MVFR CIGS.
IZZI
&&
.MARINE...
127 PM CST
A COLD FRONT WILL BEGIN TO SHIFT SOUTHWARD DOWN LAKE MICHIGAN LATE
THIS AFTERNOON...WITH WINDS EXPECTED TO PICK UP OUT OF THE NORTH
INTO TONIGHT. WINDS OVER THE LAKE WILL THEN CONTINUE TO INCREASE
INTO SUNDAY AS A QUICK MOVING CLIPPER SYSTEM TRACKS SOUTHEASTWARD
ACROSS SOUTHERN ILLINOIS. THIS WILL RESULT IN NORTHEASTERLY WINDS UP
TO 30 KT BY EARLY SUNDAY MORNING ACROSS MOST OF THE LAKE...WITH THE
STRONGEST WINDS EXPECTED ACROSS THE SOUTHERN END OF THE LAKE...WHERE
A FEW GALE FORCE GUSTS TO 35 KT ARE POSSIBLE ON SUNDAY. THIS WILL
RESULT IN WAVES UP TO 10 FEET INTO THE NORTHEAST ILLINOIS SHORES
THROUGH SUNDAY EVENING. THE WINDS WILL QUICKLY ABATE ACROSS THE LAKE
SUNDAY NIGHT AS THE LOW SHIFTS TOWARDS THE EASTERN SEABOARD.
ANOTHER WEAKENING LOW WILL SHIFT SOUTHWARD OVER OR JUST WEST OF THE
LAKE LATE MONDAY AND MONDAY NIGHT. THIS WILL RESULT IN A PERIOD OF
LIGHT SOUTHERLY WINDS OVER THE LAKE DURING THIS PERIOD. LATER IN THE
WEEK ANOTHER LOW IS EXPECTED TO IMPACT THE GREAT LAKES REGION. THIS
SYSTEM STILL HAS THE POTENTIAL TO PRODUCE A PERIOD OF STRONG
SOUTHERLY WINDS WEDNESDAY NIGHT...FOLLOWED BY STRONG NORTHERLY WINDS
THURSDAY INTO FRIDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 AM SUNDAY TO 9 AM MONDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1105 PM CST Sat Jan 24 2015
.UPDATE...
ISSUED AT 846 PM CST SAT JAN 24 2015
Overnite forecast generally on track. 18z models and HRRR indicate
that low-level thermal profile may be conducive for some sleet to
mix with rain prior to 12z in the far NW. Will add wording for
that potential as far east as Peoria.
Still plenty of uncertainty in low-level temperature forecast for
late tonight and Sunday with most models indicate temperatures
near or possibly just above freezing at the surface and warmer
temps around 925 mb through the morning then rapid cooling behind
the expected cliper system during the afternoon and a changeover.
The trend of the solution envelope has also shifted south over the
past few days which if it continues will bring CAA into the
northern counties faster. Still appears that accumulations of an
1"-3" still possible mainly northeast of I-74 with the best
chances of accumulation occurring on elevated and grassy surfaces.
&&
.SHORT TERM...(Tonight)
ISSUED AT 236 PM CST SAT JAN 24 2015
Abundant sunshine occurring across the forecast area this afternoon,
which has allowed temperatures to warm well into the 40s, with some
50 degree readings about to occur in west central Illinois. The
leading edge of the high clouds from our incoming storm system are
about to cross the Mississippi River, and should become more
widespread over our area toward sunset.
Latest surface map shows the low center in central North Dakota. The
12Z models have trended a bit south again with the track, but are in
general agreement with a position in the Quincy area by sunrise
Sunday, and associated warm front extending east across the northern
CWA. With the CWA largely in the warm sector overnight, have shown
only a couple degrees of temperature fall tonight with the entire
area remaining well above freezing. Have updated the alignment and
timing of the PoP`s to focus on the period after midnight, and also
increase them from the west. Higher resolution models start
spreading precipitation in from the west after about 3 am, which
soundings show as rain, although a bit of sleet is hinted at across
the northwest CWA, with a dry wedge between 925 and 850 mb.
&&
.LONG TERM...(Sunday through Saturday)
ISSUED AT 236 PM CST SAT JAN 24 2015
After several days of significant spread and large north/south
swings in the storm track with Sunday`s clipper system, the models
have finally come into better agreement. The current consensus is
kind of a middle ground of the north/south extremes of the past few
days, although it leans more toward the southern tracks that had
been advertised. A more southern track is preferred considering how
much digging the clipper wave still appears to be doing on water
vapor imagery as it is diving into the northern Rockies/Plains.
Would not be surprised to see the ultimate track to be a little
south of the current model consensus, a track which result in an
associated shift of the main snowfall track.
The surface low center should be near the extreme tip of
west-central Illinois at 12Z Sunday, and will quickly race to the
southern tip of Ohio by 06Z Monday. The bulk of the precipitation
with this system should occur during the daylight hours Sunday as a
quick shot of modest isentropic ascent ahead of the wave, and jet
forcing/DPVA as the upper trof axis, swing through.
Measurable precipitation now appears to be a given areawide with
this system, and have boosted PoPs to Categorical (80%+) on Sunday.
The main question is rain versus snow, and how much snow will
accumulate. Temperatures to start the day across most if not all of
the forecast area will be too warm for snow to reach the ground
thanks to the southerly flow ahead of the clipper. Forecast
soundings suggest the low level thermal profile will steadily become
cool enough for a rain to snow transition from northwest to
southeast during the day as cold air wraps in on the north side of
the surface low. The change over should occur around Galesburg near
sunrise, along a Springfield to Champaign line around midday, and
south of I-70 by shortly after sunset. The current track and speed
of change over to snow supports 1-3 inch accumulations along and
north of the I-74 corridor, with an inch or less south of there. Any
lingering snow will quickly come to an end Sunday evening as the
clipper races south/east of the area.
Another wave, much weaker than the first one, will pass north of the
forecast area on Monday. Have started to back down from the already
low snow chances we had over northern portions of the forecast area
with this wave. The lead clipper is expected to develop into a major
east coast storm after it leaves the area, and Monday`s wave is
essentially shearing out into the much stronger system.
A stronger wave coming off the Pacific is expected to move through
the Midwest by Wednesday night and Thursday. At this point, this
system appears warm enough to be mainly a rain producer. Another
system may arrive to start next weekend, but model agreement in the
details is pretty low at this time.
Temperatures through the next week should be at or above normal. The
coolest readings are likely Monday/Tuesday behind the main clipper,
and again Friday/Saturday behind the midweek system.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1105 PM CST SAT JAN 24 2015
Low-level thermal profiles still a challenge as the 00z models
continue to be on the warm side of the current forecast despite
the low tracking a bit further south. Latest water vapor imagery
and upstream observations suggest that the southward trend in the
forecast envelope may continue. However one impact of the further
south trajectory may be to delay post-system low-level CAA. Cold
air remains bottled up over eastern North Dakota, Minnesota, and
northern Wisconsin and is not yet being funneled into the storm.
Will delay switchover of precip from liquid to frozen and confine
a period of possible sleet to KPIA and KBMI.
Gusty north winds still look likely after storm passage Sunday
afternoon as forecasted gradient tightens.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barker
SHORT TERM...Geelhart
LONG TERM...Bak
AVIATION...Barker
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
440 AM EST SUN JAN 25 2015
.SYNOPSIS...
ISSUED AT 430 AM EST SUN JAN 25 2015
AN AREA OF LOW PRESSURE WILL MOVE FROM SOUTHERN IOWA THIS MORNING
TO SOUTHWEST INDIANA BY MID AFTERNOON AND THEN THROUGH KENTUCKY
TONIGHT. THIS CLIPPER SYSTEM WILL SPREAD ACCUMULATING SNOW OVER
PARTS OF NORTH CENTRAL AND NORTHERN INDIANA AND NORTHWEST OHIO
TODAY WITH RAIN SOUTH OF THIS AREA. HIGH TEMPERATURES WILL
OCCUR THIS MORNING WITH READINGS RANGING FROM THE LOWER 20S NORTH
TO UPPER 30S SOUTH. EXPECT FALLING TEMPERATURES DURING THE DAY.
LOWS TONIGHT WILL BE VERY COLD WITH SINGLE DIGITS ACROSS THE NORTH
AND TEENS SOUTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EST SUN JAN 25 2015
CHALLENGING SHORT TERM FORECAST AS PCPN TYPE IN QUESTION EARLY TODAY
AND SNOWFALL AMOUNTS WILL DEPEND ON TIMING OF CHANGEOVER TO ALL
SNOW. 00Z MODELS GENERALLY IN GOOD AGREEMENT SYNOPTICALLY WITH
ALMOST ALL SOLUTIONS TAKING SURFACE LOW SOUTHEAST FROM IA THIS
MORNING TO NEAR KEVV BY EARLY AFTERNOON...THEN EAST ACROSS NORTHERN
KENTUCKY TONIGHT. PRECIPITATION WILL SPREAD EAST ACROSS THE LOCAL
AREA TODAY AHEAD AND NORTH OF THE LOW.
STRONG MERIDIONAL JET DIVING SOUTH THROUGH THE PLAINS WILL DRIVE
CLIPPER SYSTEM SOUTHEAST TODAY. LOW LEVEL NORTHEAST FLOW WILL
INCREASE AND THIS WILL BRING COLDER AIR SOUTH HELPING ERODE WARM
LAYER ALOFT AND CHANGE PCPN OVER TO ALL SNOW FROM NORTH TO SOUTH.
THERE IS A BIT OF A CONCERN THOUGH AS MOST HIRES GUIDANCE HAS BEEN
ANYWHERE FROM 2 TO 5 DEGREES TOO WARM WITH SFC TEMPS EARLY THIS
MORNING ACROSS LOWER MICHIGAN. AS OF 08Z THOUGH WE ARE FINALLY
STARTING TO SEE A THERMAL RESPONSE IN SFC OBS WITH TEMPS DROPPING A
FEW DEGREES. THIS IS ENCOURAGING BUT STILL CONCERNED THAT MODELS ARE
A FEW HOURS TOO FAST BRINGING THE COLDER AIR SOUTH WHICH IN TURN
COULD DELAY CHANGEOVER IN FAR SOUTH UNTIL MID AFTERNOON.
HRRR...RUC AND LAMP GUIDANCE HAVE BEEN PLAYING CATCHUP ALL NIGHT.
HAVE MANUALLY ADJUSTED HOURLY SFC TEMPS WITH SLIGHTLY SLOWER COOLING
THAN RUC GUIDANCE SUGGESTS. DO EXPECT COLDER AIR TO QUICKLY MOVE SOUTH
ONCE CLIPPER GETS CLOSER AND PRESSURE GRADIENT TIGHTENS LATER THIS
MORNING.
MEANWHILE...LACK OF LOW CLOUDS ALONG WITH LIGHT WINDS IN THE WESTERN
CWA HAS ALLOWED SFC TEMPS THERE TO DROP TO AROUND FREEZING WITH SOME
FOG DEVELOPMENT. DO EXPECT TEMPS HERE TO RISE ABOVE FREEZING AHEAD
OF PCPN ARRIVAL WITH SFC TEMPS ACROSS CENTRAL ILLINOIS IN THE MID TO
UPPER 30S EARLY THIS MORNING. THIS COMBINED WITH 1000-850MB WARM
TONGUE OF 2 TO 4C DEPICTED BY HIRES GUIDANCE SUGGEST A MIX OF RAIN
AND SNOW UNTIL WARM LAYER IS FULLY ERODED. TOP DOWN METHOD ACTUALLY
DEPICTS A FEW HOURS OF JUST RAIN ACROSS THE EXTREME SOUTHERN CWA
LATE MORNING INTO EARLY AFTERNOON BEFORE FULLY CHANGING OVER TO
SNOW.
THE FARTHER SOUTH TRACK OF CLIPPER HAS ALSO MEANT A SOUTHWARD SHIFT
IN STRONGEST FORCING AND HEAVIEST PCPN AXIS. STRONGEST FGEN FORCING
AND BANDING POTENTIAL NOW LOOKS TO BE JUST SOUTH OF OUR AREA. THIS
COMBINED WITH MIXED PCPN AND DELAYED CHANGEOVER TO SNOW HAS LED TO
DECREASED SNOW AMOUNTS OVER THE ENTIRE AREA. MODEL QPF NOW GENERALLY
AROUND A QUARTER INCH SOUTH OF THE US24 CORRIDOR. MIXING RATIOS OF 3
TO 4 G/KG AND PWATS AROUND 0.5 INCHES STILL A CONCERN...ESPECIALLY
IF ANY BANDING DEVELOPS. STILL EXPECT A SWATH OF 2 TO 4 INCHES
ACROSS THE FAR SOUTH AND THE HIGHER END AMOUNTS SOUTHEAST WHERE
PIVOT POINT AND SNOW THIS EVENING TAKE ADVANTAGE OF SLIGHTLY BETTER
RATIOS. ISOLATED AMOUNTS OF 5 INCHES NOT OUT OF QUESTION IF BANDING
CLIPS THIS AREA. WITH THIS BEING MID WINTER AND EXPECTATION OF A WET
2 TO 4 INCHES WITH LOW IMPACTS FOR TRAVEL HAVE OPTED TO NOT ISSUE
ANY ADVISORY AT THIS TIME. WILL HIGHLIGHT SNOWFALL IN AN SPS AND
HWO.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 439 AM EST SUN JAN 25 2015
NEXT CLIPPER-TYPE SYSTEM TO POTENTIALLY IMPACT THE AREA WILL ARRIVE
ON MONDAY NIGHT. FORCING MECHANISM IS REALLY MORE ACCURATELY
DESCRIBED AS JUST A THIN RIBBON OF CYCLONIC SHEAR VORTICITY ON THE
UPWIND SIDE OF DEEPENING EAST COAST TROUGH. AS SUCH...FORCING FOR
ASCENT IS PRETTY MINUSCULE AND RESIDENT AIRMASS...AT LEAST IN THE
MIDLEVELS...IS VERY DRY. WEAK 285K ISENTROPIC ASCENT AND SUBTLE LOW
LEVEL MOISTURE ADVECTION MAY GENERATE SOME VERY LIGHT SNOW BUT
LITTLE TO NO ACCUMULATION IS EXPECTED. PREFERENCE STILL LIES WITH
THE DRIER/FURTHER SOUTHWEST CANADIAN AND EUROPEAN SOLUTIONS.
ACTUALLY AM A LITTLE CONCERNED ABOUT POTENTIAL FOR FREEZING DRIZZLE.
NAM AND GFS FORECAST SOUNDINGS INDICATE DEEP ENOUGH SATURATION TO
SUPPORT ICE NUCLEATION BUT JUST BARELY AND AM CONCERNED THEY ARE
OVERDOING THE EXTENT OF LOW LEVEL MOISTURE AND ASCENT. WILL HOLD OFF
ON INCLUDING IN THE FORECAST FOR NOW GIVEN THE HIGHER PROBABILITY
THAT ANY PRECIPITATION THAT DOES MANAGE TO OCCUR WILL DO SO IN AN
ENVIRONMENT ADEQUATELY SATURATED TO SUPPORT ICE NUCLEI AND OTHER
LOCATIONS WILL SIMPLY REMAIN DRY. SOMETHING TO KEEP AN EYE ON THOUGH.
MORE IMPRESSIVE WAVE IS SET TO PLOW OVER THE WEST COAST RIDGE ON
WEDNESDAY. THIS ACTUALLY FORCES DOWNSTREAM HEIGHT RISES LOCALLY WITH
A BRIEF RETURN TO SOUTHWEST FLOW AND WARMER TEMPERATURES. SHORTWAVE
WILL THEN ENTER OUR REGION ON THURSDAY WITH THE NEXT DECENT CHANCE
OF PRECIP. NEEDLESS TO SAY....FORECAST CONFIDENCE IN EXACT TRACK IS
LOW AND THIS WILL HAVE A LARGE IMPACT ON THERMAL PROFILES AND QPF
TOTALS. CURRENTLY APPEARS THE BEST CHANCE FOR SIGNIFICANT SNOW WILL
REMAIN OVER CENTRAL MICHIGAN WITH MORE OF A MIX ACROSS NORTHERN
INDIANA AND OHIO. THIS WILL UNDOUBTEDLY CHANGE AS WE GET CLOSER
THOUGH.
AFTER A COLD START ON MONDAY...TEMPERATURES WILL QUICKLY RETURN TO
VALUES AT OR ABOVE NORMAL FOR THE MIDWEEK PERIOD. COOLER TEMPS
EXPECTED AFTER THURSDAY`S WAVE BUT MUCH COLDER CONDITIONS STILL
APPEAR POSSIBLE EARLY NEXT WEEK AFTER A THIRD WAVE/ARCTIC FRONT
PASSES OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1236 AM EST SUN JAN 25 2015
MVFR CIGS WERE ACROSS THE TAF SITES AT ISSUANCE BUT CONDITIONS
WERE HIGHLY VARIABLE WITH MUCH OF WEST CENTRAL AND NORTHWEST
INDIANA BEING VFR. AN AREA OF LOCAL VIS BELOW 1SM BR WAS
DEVELOPING AROUND KVPZ. HIRES GUIDANCE ACTUALLY CAPTURES THIS
SMALL AREA AND EXPANDS IT EAST TOWARD KSBN OVERNIGHT. WILL HAVE TO
MONITOR BUT DID INTRODUCE MVFR VIS TO KSBN. CLIPPER SYSTEM TO
DIVE EVEN FURTHER SOUTH NOW WITH SFC LOW MOVING OVER KEVV TODAY.
HEAVIER SNOWFALL WILL BE SOUTH OF TERMINALS BUT STILL EXPECT TO
SEE LIGHT SNOW FROM LATE MORNING TO EARLY EVENING WITH IFR AT KSBN
AND LIFR STILL POSSIBLE AT KFWA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
349 AM CST SUN JAN 25 2015
...UPDATED SHORT TERM DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CST SUN JAN 25 2015
A 500 MILLIBAR SHORTWAVE TROUGH WAS MOVING SOUTHEAST OVER THE
CENTRAL PLAINS EARLY THIS MORNING. AT THE SURFACE, AN ASSOCIATED LOW
PRESSURE SYSTEM WAS ALSO TRACKING SOUTHEAST OVER SOUTHERN IOWA. THE
UPPER WAVE WAS MOVING INTO OKLAHOMA EARLY THIS MORNING AS LIGHT
PRECIPITATION THAT WAS OVER THE AREA EARLIER IN THE NIGHT HAD MOVED
INTO EASTERN OKLAHOMA AND CLOUDS WERE DIMINISHING OVER WESTERN
KANSAS.
FAIRLY STRONG WINDS ALOFT WERE ALSO MOVING SOUTHEAST OVER THE AREA
IN THE WAKE OF THE SHORTWAVE. THE KDDC VWP WAS SHOWING 50-55 KNOT
WINDS OFF THE SURFACE WHICH IS IN GOOD AGREEMENT WITH 850 MILLIBAR
WIND PROGS FROM THE RUC13 AND HRRR. THESE MODELS SHOW A BROAD AREA
OF 50-60 KNOT WINDS OVER SOUTHWEST KANSAS EARLY THIS MORNING WHICH
MAKES SENSE GIVEN THE NUMEROUS REPORTS OF 25-30 KNOT WINDS REPORTS
FROM AREA AWOS`S. THE MODELS SHOW THE AREA OF STRONGER WINDS GRADUALLY
PROPAGATING SOUTHWARD INTO OKLAHOMA BY MID/LATE MORNING. WE SHOULD
SEE THE STRONG WINDS CONTINUING THROUGH MUCH OF THE DAY. THERE COULD
BE A SMALL WINDOW OF OPPORTUNITY FOR 50+ KNOT WIND GUSTS AROUND
MEDICINE LODGE LATER THIS MORNING BUT THE STRONGEST WINDS SHOULD
BE SOUTH OF SOUTHWEST KANSAS BY THE TIME THE BOUNDARY LAYER BEGINS
TO MIX OUT. WINDS IN THE LOWER ATMOSPHERE WILL GRADUALLY WEAKEN DURING
THE AFTERNOON HOURS. WE SHOULD SEE WINDS DROP OFF FAIRLY QUICKLY TOWARD
SUNSET AS THE BOUNDARY LAYER DECOUPLES.
THE MODELS ARE SHOWING A COOLER DAY FOR SOUTHWEST KANSAS THAN WAS
PREVIOUSLY THOUGHT. 850 MILLIBAR TEMPERATURES THIS AFTERNOON WILL BE
COOLER THAN SATURDAY BY SOME 4-8 DEGREES CELSIUS. THIS WILL TRANSLATE
TO HIGHS RANGING FROM AROUND 50 AT HAYS TO THE MID/UPPER 50S FROM
DODGE CITY WEST TO THE COLORADO LINE. SURFACE WINDS TONIGHT WILL
GRADUALLY SWITCH TO THE WEST AND COULD INCREASE AGAIN TO AROUND
10-12 KNOTS. THIS COULD KEEP LOW TEMPERATURES HELD UP IN THE LOWER
TO MIDDLE 30S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 308 AM CST SUN JAN 25 2015
UPPER LEVEL RIDGING WILL PERSIST OVER THE ROCKIES MONDAY AND
TUESDAY BEFORE A SHORTWAVE TROUGH FLATTENS OUT THE RIDGE ON
WEDNESDAY AND PROGRESSES ACROSS THE PLAINS. THIS ENTIRE PERIOD
WILL BE CHARACTERIZED BY WARM TEMPERATURES WITH VARYING WIND
DIRECTIONS FROM DAY TO DAY IN RESPONSE TO SUBTLE CHANGES IN THE
SURFACE PRESSURE FIELD. HIGHS OUGHT TO REACH INTO THE UPPER 60S TO
LOWER 70S. A COLD FRONT WILL PASS ACROSS WESTERN KANSAS WEDNESDAY
AFTERNOON IN THE WAKE OF THIS SHORTWAVE TROUGH, WITH COOLER
TEMPERATURES RETURNING FOR WEDNESDAY NIGHT THROUGH THE REMAINDER
OF THE WEEK AS SURFACE HIGH PRESSURE BUILDS IN.
THERE IS A LOT OF UNCERTAINTY IN THE FORECAST AFTER FRIDAY AS THE
VARIOUS MODELS ARE EXHIBITING LOTS OF VARIABILITY WITH RESPECT TO
THE AMPLITUDE OF AN UPPER LEVEL LOW OVER BAJA. COLD AIR CONTINUES
TO BE DELIVERED INTO THE MIDWEST AND GREAT LAKES REGIONS. IF THE
SOUTHWESTERN SYSTEM PROGRESSES FAR ENOUGH EAST AND INTERACTS WITH
THE WESTERN AND SOUTHERN EDGE OF THE COLD DOME, THEN SNOW WOULD BE
POSSIBLE. THE OVERALL TREND IN THE MODELS OVER THE PAST FEW RUNS
HAS BEEN FOR A STRONGER SYSTEM OVER THE DESERT SOUTHWEST AND BAJA.
BUT IT IS VERY UNCERTAIN JUST HOW FAR NORTHEAST ANY PRECIPITATION
WOULD OCCUR AND JUST HOW COLD IT WILL BE OVER WESTERN KANSAS. FOR
NOW, THERE IS FAIRLY HIGH CONFIDENCE IN A CHANGE TO COOLER OR COLDER
TEMPERATURES FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1131 PM CST SAT JAN 24 2015
A FEW LINGERING LIGHT SHOWERS OR SPRINKLES ACROSS SOUTHWEST KANSAS
WILL QUICKLY MOVE OUT OF THE AREA DURING THE FIRST FEW HOURS OF
THIS TAF PERIOD. GUSTY NORTHWEST WINDS WILL CONTINUE ACROSS THE
AREA OVERNIGHT AND WILL INCREASE TO AROUND 25-30 KNOTS WITH GUSTS
TO 40 KNOTS AT TIME BY MID TO LATE MORNING SUNDAY. WINDS WILL
DIMINISH RAPIDLY TOWARD SUNSET ON SUNDAY
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 56 34 70 35 / 0 0 0 0
GCK 57 34 71 35 / 0 0 0 0
EHA 55 37 69 35 / 0 0 0 0
LBL 57 33 69 35 / 0 0 0 0
HYS 50 31 70 36 / 0 0 0 0
P28 54 31 70 37 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...FINCH
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1127 PM CST Sat Jan 24 2015
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Sunday)
Issued at 253 PM CST SAT JAN 24 2015
An upper level trough located across the northern plains this
afternoon will dig southeast into the mid MS river valley by Sunday
Afternoon.
The stronger ascent ahead of this upper level trough will remain
across the northern plains into the Midwest and OH river valley. The
mesoscale models show another area of stronger ascent developing
within the left exit region, ahead of an 80 KT H5 jet max, which
will dig from eastern MT this afternoon, southeast across western
KS, into northeast OK through the night. Both the Advanced Research
and Non-hydrostatic WRF model solutions show an area of light rain
developing across west central KS this evening in the region of the
left exit region of the H5 jet. ATTM, the area of light rain will
move southeast ahead of the H5 jet max and spread southeast across
south central KS into northeast OK through the night. The 12Z GFS
model is the only solution showing the area of steadier light rain
moving across the southern half of the CWA this evening. I will be
leaning more towards the ARW, NMM and HRRR solutions.
Most of the CWA will only see occasional sprinkles or very light
rain showers through the night into the morning hours of Sunday as
the H5 trough axis moves southeast. Forecast soundings continue to
show a drier layer air within the lowest 6,000 feet of the
atmosphere. Overnight lows will be mild with westerly winds of 10 to
20 MPH. Most areas should see overnight lows only dropping into the
upper 30s.
Sunday, as the upper trough amplifies across northern MO, wrap
around rain showers are possible across the northeast and east
central KS. These showers look to be light with only a trace
to 0.01 inch of QPF forecasted. A surface/925mb low will deepen
across northern MO through the day. Northwest winds will increase
through the mid morning hours to 20 to 30 MPH with gusts up to 40
MPH. The southern counties of the CWA may flirt with wind advisory
criteria during the late morning and early afternoon hours. The
low-level CAA will only allow high temperatures to reach the lower
to mid 40s across the eastern half of the CWA, where clouds may
continue through most of the day. The western counties may see some
afternoon insolation which may help highs to reach into the mid to
upper 40s.
.LONG TERM...(Sunday Night through Saturday)
Issued at 253 PM CST SAT JAN 24 2015
Sunday Night through Monday Night ...
By Sunday night, the vertically-stacked surface low and mid-level
low will be situated over the Ohio River Valley with
north-northwesterly flow aloft prevailing across the central U.S. A
narrow ridge of surface high pressure will spill southward into the
forecast area Sunday night into Monday resulting in mostly clear
skies and light winds. As a result, decent radiational cooling will
help drop overnight low temperatures into the mid/upper 20s.
Models show the next surface low positioned over the far northern U.S.
and tracking toward the Great Lakes region through Monday night. An
associated cold front will extend southward across the Northern and
Central Plains Monday morning and is expected to skim southeastward
across the forecast area from late morning through the afternoon
hours. Since this front looks to barely extend far enough south into
the area, there should not be a strong wind shift associated with
this frontal passage. As a result, models show winds gradually
veering from southwest to west-northwest through the day. Soundings
are very dry so don`t even expect much in the way of cloud cover
with this frontal passage. With a thermal ridge in place just west
of the forecast area and decent downslope winds expected, should see
another mild day with high temperatures reaching into the upper 50s
east to middle 60s west. An area of surface high pressure will
advance into the Northern and Central Plains behind the front, with
mostly clear skies and light northwesterly winds resulting in low
temperatures dropping into the low 30s by Tuesday morning.
Tuesday through Saturday Night...
A pattern of benign weather is expected Tuesday through Friday as a
dry forecast remains in place. A wave will push through the area on
Wednesday evening; however, any precipitation associated with this
energy will be to the north of the area. The next mention of
precipitation is Saturday, associated with a shortwave amplifying in
the Rocky Mountains. Two completely different solutions are seen by
the models with the ECMWF proposing energy with this system will
stay well south keeping the area completely dry, while the GFS
solution continues to amplify this wave allowing for a moderate
amount of precipitation. Due to such a robust solution with the
GFS, have put in 20 percent chances for PoPs over the entire area
Saturday, with a chance for both rain and snow. As of right now,
confidence of how this system will play out is low and should
continue to be monitored.
As for temperatures, Tuesday and Wednesday will continue to be above
normal with highs topping out in the upper 50s/lower 60s. A weak
cold front associated with the system on Wednesday will lower
temperatures slightly Thursday and Friday, with highs in the mid 40s
and lows below freezing. Saturday will be even cooler as winds
shift from the north bringing highs back to climatological normals.
&&
.AVIATION...(For the 06Z TAFs through 06Z Sunday Night)
Issued at 1124 PM CST SAT JAN 24 2015
With hit and miss light rain showers near terminals will continue
with VCSH for the first half of the forecast period. Winds pick up
gusts in the next few hours and continue through the morning into
the afternoon, before diminishing toward sunset.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Heller/Hennecke
AVIATION...67
AREA FORECAST DISCUSSION
NWS JACKSON KY
113 AM EST SUN JAN 25 2015
.UPDATE...
ISSUED AT 111 AM EST SUN JAN 25 2015
IR SATELLITE SHOWING SOME MAINLY HIGH CLOUDS BEGINNING TO MOVE INTO
PORTIONS OF EASTERN KENTUCKY THIS HOUR. THERE HAVE ALSO CONTINUED TO
BE SOME SCATTERED MID LEVEL CLOUDS ACROSS THE FAR NORTH AND FAR EAST
TONIGHT. OTHERWISE WE ARE SEEING SOME PATCHY VALLEY FOG TONIGHT UNDER
MOSTLY CLEAR SKIES COMBINED WITH SNOW SEEN YESTERDAY. FRESHENED UP
GRID BASED ON LATEST OBS AND TRENDS WITH NO MAJOR UPDATES NEEDED.
UPDATE ISSUED AT 1044 PM EST SAT JAN 24 2015
MOSTLY CLEAR SKIES ARE CURRENTLY BEING SEEN ACROSS EASTERN KENTUCKY
BESIDES SOME SCATTERED HIGHER BASED STRATOCU SKIRTING BY IN THE
NORTH...AS WELL AS THE LAST OF THE LOWER CLOUDS EXITING FAR
SOUTHEASTERN KENTUCKY. THANKS TO THE CLEARING...VALLEYS HAVE DIPPED
INTO THE UPPER 20S IN SPOTS. MID AND HIGH LEVEL CLOUDS WILL BE MOVING
IN AFTER MIDNIGHT...WHICH SHOULD TEMPER THE DROP OFF...HOWEVER HAVE
LOWERED THE COOLER VALLEYS TO AROUND 27 DEGREES GIVEN THE CURRENT
TRENDS. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 711 PM EST SAT JAN 24 2015
A BATCH OF LOW CLOUDS IS CURRENTLY MOVING EAST ACROSS OUR AREA
ASSOCIATED WITH A PASSING SHORT WAVE TROUGH MOVING THROUGH THE OHIO
VALLEY. THE LATEST IR SATELLITE IMAGERY REVEALS A PRETTY DEFINED
BACK EDGE TO THESE CLOUDS...AND THE LATEST RUC DATA SUGGESTS THAT
ONCE THESE EXIT IN THE NEXT FEW HOURS...THAT ADDITIONAL LOW CLOUDS
WILL BE HARDER TO COME BY GIVEN THE WEST TO SOUTHWEST WINDS TO
REMAIN IN PLACE AND A LITTLE SUBSIDENCE TO FOLLOW THE EXITING WAVE.
MID AND HIGH LEVEL CLOUDS WILL LIKELY INCREASE ACROSS THE AREA AFTER
MIDNIGHT OUT AHEAD OF THE NEXT SYSTEM. HAVE LEFT THE LOWS AROUND THE
30 DEGREE MARK IN PLACE FOR NOW...ALTHOUGH WILL HAVE TO KEEP AN EYE
ON SHELTERED VALLEYS THAT MAY DECOUPLE AND TAKE ADVANTAGE OF SOME
EVENTUAL PARTIAL CLEARING. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 415 PM EST SAT JAN 24 2015
CURRENT CONDITIONS ACROSS THE AREA FEATURE SOME EXTENSIVE CLOUD COVER
MOVING SOUTHEAST THROUGH THE AREA ASSOCIATED WITH A WEAK TROUGH. WITH
THIS HAS BEEN SOME LIGHT FLURRY ACTIVITY OR SPRINKLES MAINLY TAKING
AIM OVER THE NORTHEASTERN PORTION OF EASTERN KENTUCKY. WILL KEEP A
MENTION OF FLURRIES AND A POSSIBLE SNOW SHOWER OVER THE AREA AND
ESPECIALLY OVER THE EAST IN MARTIN AND PIKE COUNTY. WITH THIS
FEATURE...CLOUD COVER WILL REMAIN OVER THE AREA THROUGH THIS EVENING
AND THROUGH TONIGHT. THIS HAS KEPT TEMPERATURES SUPPRESSED THROUGH THE
DAY TODAY BUT WITH WINDS OUT OF THE SOUTHWEST REMAINING UP IN MOST
LOCATIONS TONIGHT...WILL LOOK LIKE TEMPS MAY REMAIN STEADY OR SLOWLY
FALL THROUGH THE NIGHT. HOWEVER...SOME CONCERN HERE WILL BE OVER THE
SOUTH WHERE A FEW BREAKS IN THE CLOUD COVER MAY RESULT IN TEMPS
FALLING FURTHER...ESPECIALLY IN THE VALLEYS. AS WELL...SOME CONCERN
FOR PATCHY FOG WAS A POSSIBLE OCCURRENCE TONIGHT WHERE SNOW HAD
FALLEN IN THE NORTH BUT WITH REMAINING CLOUD COVER AND WINDS
SLIGHTLY UP...WILL LIKELY NOT DEVELOP MORE THAN PATCHY INSTANCES IF
AT ALL SO LEFT THIS OUT OF THE FORECAST.
CONCERNING SUNDAY THROUGH MONDAY WITH THE APPROACHING CLIPPER
SYSTEM...MODELS HAVE TRENDED DRY WITH THIS FEATURE AND SLIGHTLY
WARMER BUT WILL STILL SEEM TO BE DEALING WITH SHOWERS FOR SUNDAY AS
THIS FRONT ARRIVES. SOUTHWEST FLOW WILL BRING TEMPERATURES UP INTO
THE 40S DURING THE DAY ON SUNDAY BEFORE THE COLDER AIR MOVES IN
SUNDAY NIGHT. DEALING WITH A CONVECTIVE PROCESS AND THE RIGHT WIND
DIRECTION FOR UPSLOPE FLOW WILL MAKE FOR THE CHANGE OVER TO SNOW BY
LATE SUNDAY NIGHT AND INTO MONDAY...ESPECIALLY IN THE HIGHER
ELEVATIONS. AS THE CASE IN THESE EVENTS...THE DEPTH OF THE MOISTURE
IN THE COLUMN DOES BEGIN TO EXIT COME MONDAY AFTERNOON DURING THE
UPSLOPE PORTION OF THIS EVENT SO SNOWFALL TOTALS WILL BE LIMITED FOR
THE LATE SUNDAY NIGHT THROUGH MONDAY PERIOD. RIGHT NOW THINKING THAT
THE VALLEYS AND THE BLUEGRASS REGION WILL BE UNDER AN INCH TOTAL WITH
MORE THAN AN INCH ABOVE 2000 FEET. WILL MENTION THIS THREAT IN THE
HWO BUT THE OCCURRENCE BEING SUNDAY NIGHT INTO MONDAY MAY REQUIRE SOME
FURTHER CONSIDERATION TO HIGHLIGHT THE IMPACT TO THE MORNING COMMUTE
ON MONDAY.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 PM EST SAT JAN 24 2015
A RATHER ACTIVE PATTERN IS ANTICIPATED THROUGH THE PERIOD. MODELS
WERE IN GENERALLY IN GOOD AGREEMENT AND THE FORECAST WAS KEPT VERY
CLOSE TO THE MODEL CONSENSUS BLEND. AT THE START OF THE
PERIOD...A TROUGH IS EXPECTED TO EXTEND FROM EASTERN CANADA INTO THE
GREAT LAKES REGION AND EASTERN SEABOARD. MEANWHILE A RIDGE IS
EXPECTED TO EXTEND FROM MEXICO NORTH INTO THE ROCKIES. THIS WILL
LEAD TO NW FLOW ALOFT INITIALLY WITH A SERIES OF SHORTWAVES EXPECTED
TO DROP DOWN ACROSS THE LOWER OH VALLEY REGION AND APPALACHIANS. THE
TROUGH AXIS IS EXPECTED TO GRADUALLY MOVE OFF THE EASTERN SEABOARD
BY MIDWEEK...WITH THE RIDGE SHIFTING EAST TO THE PLAINS STATES AND
EVENTUALLY OH VALLEY REGION. HOWEVER...A SHORTWAVE MOVING AROUND THE
RIDGE AND A TROUGH IN THE NORTHERN STREAM WILL BEGIN TO INTERACT
OVER THE PLAINS AT MIDWEEK AND THE RESULTING TROUGH SHOULD DAMPEN
THE RIDGE AND APPROACH THE REGION LATE WED NIGHT. THIS SYSTEM WILL
MOVE ACROSS THE GREAT LAKES AND OH VALLEY REGION ON THU INTO
THURSDAY NIGHT. THE ASSOCIATED SFC LOW IS EXPECTED TO TRACK NORTH OF
THE OH RIVER AND THEN INTO THE NORTHEAST OR MID ATLANTIC STATES.
THIS WOULD BRING THE TRAILING COLD FRONT ACROSS EAST KY ON THU TO THU
EVENING.
FROM FRI INTO SATURDAY..THE MODEL CONSENSUS IS FOR SOME FLATTENING
OF THE FLOW AT LEAST BRIEFLY FROM THE PLAINS INTO THE EASTERN CONUS
THOUGH ANOTHER SHORTWAVE WILL BEGIN TO APPROACH THE AREA LATE IN THE
PERIOD.
THE SHORTWAVES IN NW FLOW SHOULD BRING AT LEAST PERIODS OF CLOUDS OR
PROLONG CLOUDS ACROSS THE REGION WITH THE LOW LEVEL FLOW MAINTAINING
AN UPSLOPE COMPONENT. THERE ARE SOME TIMING DIFFERENCES FOR THE MON
NIGHT TO TUE PERIOD WITH THE 12Z GFS RECENT NAM RUNS ARE ALSO MORE
MOIST THE 12Z ECMWF. SOME LIGHT SNOW OR FLURRIES AS WELL AS SNOW
SHOWERS WILL BE POSSIBLE ESPECIALLY DURING DAYTIME HEATING ON TUE
WHICH WOULD STEEPEN LAPSE RATES. ANY SNOW SHOWERS COULD PRODUCE AT
LEAST SOME LOCALIZED LIGHT AMOUNTS MON NIGHT INTO TUE NIGHT. FOR
POPS DURING THIS PERIOD...WENT A BIT HIGHER THAN THE MODEL BLEND
CLOSER TO PERSISTENCE FROM THE PREVIOUS FORECAST. GENERALLY DRY
WEATHER IS EXPECTED BRIEFLY AT MIDWEEK.
FOR LATE WED NIGHT INTO THU...AT THE ONSET OF THE PRECIPITATION
WETBULBING COULD LEAD TO A MIX WITH SNOW DEPENDING ON HOW QUICKLY IT
ARRIVES. HOWEVER...ANY PRECIPITATION WITH THIS SYSTEM SHOULD REMAIN
AS MOSTLY IF NOT ENTIRELY RAIN UNTIL THE PASSAGE OF THE COLD FRONT.
TEMPERATURES SHOULD AVERAGE BELOW NORMAL FOR TUE INTO WED...BUT THEN
MODERATE TO ABOVE NORMAL ON THU IN BETWEEN SYSTEM UNDER THE
INFLUENCE OF WEAK RIDGING. BEHIND THE SHORTWAVE AND COLD
FRONT...TEMPS SHOULD AGAIN RETURN TO BELOW NORMAL LEVELS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM EST SUN JAN 25 2015
MOST SITES ARE SEEING GENERALLY VFR CONDITIONS TONIGHT...BUT MOSTLY
CLEAR SKIES COUPLED WITH SNOW SEEN YESTERDAY IS ALLOWING FOR A SOME
PATCHY FOG MAINLY IN VALLEY LOCATIONS. THAT SAID WE ARE SEEING SOME
SITES WITH VIS RUNNING AT OR NEAR MVFR CONDITIONS TONIGHT. RIGHT NOW
WILL KEEP TAF SITES AT VFR...BUT WOULD NOT BE SURPRISED IF WE SEE
SOME BRIEF LOWERING TO MVFR VIS. SYM AND SJS HAVE SEEN SCT TO BKN MID
LEVEL CLOUD DECK STILL STREAMING ACROSS THOSE SITES THIS HOUR. MOST
OF THIS WILL CONTINUE TO MOVE SOUTH AND EAST OUT OF EASTERN KENTUCKY.
OTHERWISE MOST SITES WILL SEE INCREASING HIGH CLOUDS OVERNIGHT AHEAD
OF NEXT SHORTWAVE AND SURFACE LOW DROPPING SOUTHEAST INTO THE REGION
SUNDAY. PRECIP WILL SPREAD INTO THE REGION SUNDAY AFTERNOON WITH CIGS
CONTINUING TO LOWER AS WE MOVE INTO SUNDAY NIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...SHALLENBERGER
LONG TERM...JP
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
1233 AM EST SUN JAN 25 2015
.UPDATE...
ISSUED AT 1044 PM EST SAT JAN 24 2015
MOSTLY CLEAR SKIES ARE CURRENTLY BEING SEEN ACROSS EASTERN KENTUCKY
BESIDES SOME SCATTERED HIGHER BASED STRATOCU SKIRTING BY IN THE
NORTH...AS WELL AS THE LAST OF THE LOWER CLOUDS EXITING FAR
SOUTHEASTERN KENTUCKY. THANKS TO THE CLEARING...VALLEYS HAVE DIPPED
INTO THE UPPER 20S IN SPOTS. MID AND HIGH LEVEL CLOUDS WILL BE MOVING
IN AFTER MIDNIGHT...WHICH SHOULD TEMPER THE DROP OFF...HOWEVER HAVE
LOWERED THE COOLER VALLEYS TO AROUND 27 DEGREES GIVEN THE CURRENT
TRENDS. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 711 PM EST SAT JAN 24 2015
A BATCH OF LOW CLOUDS IS CURRENTLY MOVING EAST ACROSS OUR AREA
ASSOCIATED WITH A PASSING SHORT WAVE TROUGH MOVING THROUGH THE OHIO
VALLEY. THE LATEST IR SATELLITE IMAGERY REVEALS A PRETTY DEFINED
BACK EDGE TO THESE CLOUDS...AND THE LATEST RUC DATA SUGGESTS THAT
ONCE THESE EXIT IN THE NEXT FEW HOURS...THAT ADDITIONAL LOW CLOUDS
WILL BE HARDER TO COME BY GIVEN THE WEST TO SOUTHWEST WINDS TO
REMAIN IN PLACE AND A LITTLE SUBSIDENCE TO FOLLOW THE EXITING WAVE.
MID AND HIGH LEVEL CLOUDS WILL LIKELY INCREASE ACROSS THE AREA AFTER
MIDNIGHT OUT AHEAD OF THE NEXT SYSTEM. HAVE LEFT THE LOWS AROUND THE
30 DEGREE MARK IN PLACE FOR NOW...ALTHOUGH WILL HAVE TO KEEP AN EYE
ON SHELTERED VALLEYS THAT MAY DECOUPLE AND TAKE ADVANTAGE OF SOME
EVENTUAL PARTIAL CLEARING. UPDATES HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 415 PM EST SAT JAN 24 2015
CURRENT CONDITIONS ACROSS THE AREA FEATURE SOME EXTENSIVE CLOUD COVER
MOVING SOUTHEAST THROUGH THE AREA ASSOCIATED WITH A WEAK TROUGH. WITH
THIS HAS BEEN SOME LIGHT FLURRY ACTIVITY OR SPRINKLES MAINLY TAKING
AIM OVER THE NORTHEASTERN PORTION OF EASTERN KENTUCKY. WILL KEEP A
MENTION OF FLURRIES AND A POSSIBLE SNOW SHOWER OVER THE AREA AND
ESPECIALLY OVER THE EAST IN MARTIN AND PIKE COUNTY. WITH THIS
FEATURE...CLOUD COVER WILL REMAIN OVER THE AREA THROUGH THIS EVENING
AND THROUGH TONIGHT. THIS HAS KEPT TEMPERATURES SUPPRESSED THROUGH THE
DAY TODAY BUT WITH WINDS OUT OF THE SOUTHWEST REMAINING UP IN MOST
LOCATIONS TONIGHT...WILL LOOK LIKE TEMPS MAY REMAIN STEADY OR SLOWLY
FALL THROUGH THE NIGHT. HOWEVER...SOME CONCERN HERE WILL BE OVER THE
SOUTH WHERE A FEW BREAKS IN THE CLOUD COVER MAY RESULT IN TEMPS
FALLING FURTHER...ESPECIALLY IN THE VALLEYS. AS WELL...SOME CONCERN
FOR PATCHY FOG WAS A POSSIBLE OCCURRENCE TONIGHT WHERE SNOW HAD
FALLEN IN THE NORTH BUT WITH REMAINING CLOUD COVER AND WINDS
SLIGHTLY UP...WILL LIKELY NOT DEVELOP MORE THAN PATCHY INSTANCES IF
AT ALL SO LEFT THIS OUT OF THE FORECAST.
CONCERNING SUNDAY THROUGH MONDAY WITH THE APPROACHING CLIPPER
SYSTEM...MODELS HAVE TRENDED DRY WITH THIS FEATURE AND SLIGHTLY
WARMER BUT WILL STILL SEEM TO BE DEALING WITH SHOWERS FOR SUNDAY AS
THIS FRONT ARRIVES. SOUTHWEST FLOW WILL BRING TEMPERATURES UP INTO
THE 40S DURING THE DAY ON SUNDAY BEFORE THE COLDER AIR MOVES IN
SUNDAY NIGHT. DEALING WITH A CONVECTIVE PROCESS AND THE RIGHT WIND
DIRECTION FOR UPSLOPE FLOW WILL MAKE FOR THE CHANGE OVER TO SNOW BY
LATE SUNDAY NIGHT AND INTO MONDAY...ESPECIALLY IN THE HIGHER
ELEVATIONS. AS THE CASE IN THESE EVENTS...THE DEPTH OF THE MOISTURE
IN THE COLUMN DOES BEGIN TO EXIT COME MONDAY AFTERNOON DURING THE
UPSLOPE PORTION OF THIS EVENT SO SNOWFALL TOTALS WILL BE LIMITED FOR
THE LATE SUNDAY NIGHT THROUGH MONDAY PERIOD. RIGHT NOW THINKING THAT
THE VALLEYS AND THE BLUEGRASS REGION WILL BE UNDER AN INCH TOTAL WITH
MORE THAN AN INCH ABOVE 2000 FEET. WILL MENTION THIS THREAT IN THE
HWO BUT THE OCCURRENCE BEING SUNDAY NIGHT INTO MONDAY MAY REQUIRE SOME
FURTHER CONSIDERATION TO HIGHLIGHT THE IMPACT TO THE MORNING COMMUTE
ON MONDAY.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 PM EST SAT JAN 24 2015
A RATHER ACTIVE PATTERN IS ANTICIPATED THROUGH THE PERIOD. MODELS
WERE IN GENERALLY IN GOOD AGREEMENT AND THE FORECAST WAS KEPT VERY
CLOSE TO THE MODEL CONSENSUS BLEND. AT THE START OF THE
PERIOD...A TROUGH IS EXPECTED TO EXTEND FROM EASTERN CANADA INTO THE
GREAT LAKES REGION AND EASTERN SEABOARD. MEANWHILE A RIDGE IS
EXPECTED TO EXTEND FROM MEXICO NORTH INTO THE ROCKIES. THIS WILL
LEAD TO NW FLOW ALOFT INITIALLY WITH A SERIES OF SHORTWAVES EXPECTED
TO DROP DOWN ACROSS THE LOWER OH VALLEY REGION AND APPALACHIANS. THE
TROUGH AXIS IS EXPECTED TO GRADUALLY MOVE OFF THE EASTERN SEABOARD
BY MIDWEEK...WITH THE RIDGE SHIFTING EAST TO THE PLAINS STATES AND
EVENTUALLY OH VALLEY REGION. HOWEVER...A SHORTWAVE MOVING AROUND THE
RIDGE AND A TROUGH IN THE NORTHERN STREAM WILL BEGIN TO INTERACT
OVER THE PLAINS AT MIDWEEK AND THE RESULTING TROUGH SHOULD DAMPEN
THE RIDGE AND APPROACH THE REGION LATE WED NIGHT. THIS SYSTEM WILL
MOVE ACROSS THE GREAT LAKES AND OH VALLEY REGION ON THU INTO
THURSDAY NIGHT. THE ASSOCIATED SFC LOW IS EXPECTED TO TRACK NORTH OF
THE OH RIVER AND THEN INTO THE NORTHEAST OR MID ATLANTIC STATES.
THIS WOULD BRING THE TRAILING COLD FRONT ACROSS EAST KY ON THU TO THU
EVENING.
FROM FRI INTO SATURDAY..THE MODEL CONSENSUS IS FOR SOME FLATTENING
OF THE FLOW AT LEAST BRIEFLY FROM THE PLAINS INTO THE EASTERN CONUS
THOUGH ANOTHER SHORTWAVE WILL BEGIN TO APPROACH THE AREA LATE IN THE
PERIOD.
THE SHORTWAVES IN NW FLOW SHOULD BRING AT LEAST PERIODS OF CLOUDS OR
PROLONG CLOUDS ACROSS THE REGION WITH THE LOW LEVEL FLOW MAINTAINING
AN UPSLOPE COMPONENT. THERE ARE SOME TIMING DIFFERENCES FOR THE MON
NIGHT TO TUE PERIOD WITH THE 12Z GFS RECENT NAM RUNS ARE ALSO MORE
MOIST THE 12Z ECMWF. SOME LIGHT SNOW OR FLURRIES AS WELL AS SNOW
SHOWERS WILL BE POSSIBLE ESPECIALLY DURING DAYTIME HEATING ON TUE
WHICH WOULD STEEPEN LAPSE RATES. ANY SNOW SHOWERS COULD PRODUCE AT
LEAST SOME LOCALIZED LIGHT AMOUNTS MON NIGHT INTO TUE NIGHT. FOR
POPS DURING THIS PERIOD...WENT A BIT HIGHER THAN THE MODEL BLEND
CLOSER TO PERSISTENCE FROM THE PREVIOUS FORECAST. GENERALLY DRY
WEATHER IS EXPECTED BRIEFLY AT MIDWEEK.
FOR LATE WED NIGHT INTO THU...AT THE ONSET OF THE PRECIPITATION
WETBULBING COULD LEAD TO A MIX WITH SNOW DEPENDING ON HOW QUICKLY IT
ARRIVES. HOWEVER...ANY PRECIPITATION WITH THIS SYSTEM SHOULD REMAIN
AS MOSTLY IF NOT ENTIRELY RAIN UNTIL THE PASSAGE OF THE COLD FRONT.
TEMPERATURES SHOULD AVERAGE BELOW NORMAL FOR TUE INTO WED...BUT THEN
MODERATE TO ABOVE NORMAL ON THU IN BETWEEN SYSTEM UNDER THE
INFLUENCE OF WEAK RIDGING. BEHIND THE SHORTWAVE AND COLD
FRONT...TEMPS SHOULD AGAIN RETURN TO BELOW NORMAL LEVELS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1232 AM EST SUN JAN 25 2015
MOST SITES ARE SEEING GENERALLY VFR CONDITIONS TONIGHT...BUT MOSTLY
CLEAR SKIES COUPLED WITH SNOW SEEN YESTERDAY IS ALLOWING FOR A SOME
PATCHY FOG MAINLY IN VALLEY LOCATIONS. THAT SAID WE ARE SEEING SOME
SITES WITH VIS RUNNING AT OR NEAR MVFR CONDITIONS TONIGHT. RIGHT NOW
WILL KEEP TAF SITES AT VFR...BUT WOULD NOT BE SURPRISED IF WE SEE
SOME BRIEF LOWERING TO MVFR VIS. SYM AND SJS HAVE SEEN SCT TO BKN MID
LEVEL CLOUD DECK STILL STREAMING ACROSS THOSE SITES THIS HOUR. MOST
OF THIS WILL CONTINUE TO MOVE SOUTH AND EAST OUT OF EASTERN KENTUCKY.
OTHERWISE MOST SITES WILL SEE INCREASING HIGH CLOUDS OVERNIGHT AHEAD
OF NEXT SHORTWAVE AND SURFACE LOW DROPPING SOUTHEAST INTO THE REGION
SUNDAY. PRECIP WILL SPREAD INTO THE REGION SUNDAY AFTERNOON WITH CIGS
CONTINUING TO LOWER AS WE MOVE INTO SUNDAY NIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...SHALLENBERGER
LONG TERM...JP
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
352 AM EST SUN JAN 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EST SUN JAN 25 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
DOMINTING THE GREAT LKS BTWN HI AMPLITUDE RDG ALONG THE W COAST AND
A DEEP UPR TROF IN ERN NAMERICA CENTERED OVER NRN QUEBEC. SFC HI
PRES UNDER THIS NW FLOW IS BLDG SE THRU NW ONTARIO...WITH A COLD NNE
FLOW ON ITS SRN FLANK ADVECTING H85 TEMPS AS LO AS -15C OVER LK SUP
EARLY THIS MRNG. THE INFUSION OF THIS VERY COLD AIR OVER THE
RELATIVELY WARM LK SUP WATERS IS RESULTING IN SOME LK EFFECT SN
SHOWERS ACROSS MAINLY NCENTRAL UPR MI...WHERE THE LLVL FLOW IS
PRESENTING A MORE SGNFT UPSLOPE WIND COMPONENT. DESPITE FVRBL SN
GROWTH MICROPHYSICS WITH THE DGZ WITHIN MUCH OF THE CONVECTIVE
LYR...HI STABILITY/DRYNESS OF INCOMING AIRMASS PER THE 00Z YPL
RAOB...WHERE THE 00Z PWAT WAS ONLY 0.05 INCH AND THE SUBSIDENCE
INVRN WAS LOCATED NEAR H9 /MQT VWP INDICATES THE INVRN BASE HERE IS
NEAR 3K FT AGL/...AS WELL AS THE LARGER SCALE ACYC FLOW THAT IS
MINIMIZING LLVL CNVGC IS TENDING TO LIMIT THE INTENSITY OF THE LES.
OVER THE E...SKIES HAVE BEGUN TO CLEAR AT NEWBERRY WITH MINIMAL
OVERWATER TRAJECTORY AND SOME DOWNSLOPING OF THE LLVL NE FLOW OFF
ONTARIO...WHERE SFC DEWPTS EARLY THIS MRNG ARE AS LO AS -20 TO -25F
TO THE N OF LK SUP. LOOKING FARTHER UPSTREAM...A FAIRLY STRONG
SHRTWV IS MOVING THRU WRN CANADA OVER TOP THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE LES TRENDS ASSOCIATED WITH
THE COLD NE LLVL FLOW THAT WL PERSIST INTO THIS AFTN. FOCUS FOR TNGT
SHIFTS TO LO TEMPS AND SN CHCS LATE OVER THE W ASSOCIATED WITH
DISTURBANCE NOW TRACKING THRU WRN CANADA.
TODAY...SFC HI PRES CENTER IS FCST TO DRIFT SLOWLY TO THE SE OVER
FAR NE LK SUP BY 00Z MON. LLVL NE FLOW WL PERSIST THRU THIS
MRNG...BUT THEN WEAKEN AS THE HI CENTER MOVES CLOSER AND SFC RDG
AXIS EXTENDING TO THE SW MOVES OVHD BY 00Z. WITH THE -15C H85
ISOTHERM OVER CENTRAL LK SUP AND THE DGZ IN THE 1-3K FT LYR
ENCOMPASSING MUCH OF THE CONVECTIVE LYR...SOME FLUFFY LES WL PERSIST
IN THE NE SN BELTS OVER MAINLY THE NCENTRAL. DESPITE THE PRESENCE OF
THE DGZ AND SUFFICIENT CHILL OF THE AIRMASS...INVRN BASE NEAR 3K FT
AGL AND ACYC NATURE OF THE H925 FLOW WL CONTINUE TO LIMIT ADDITIONAL
SN ACCUMS TO AN INCH OR LESS. DURING THE AFTN WHEN THE WINDS/UPSLOPE
FORCING DIMINISH FURTHER AND THE SFC RDG AXIS BECOMES MORE
PRONOUNCED...THE LES SHOULD TEND TO DIMINISH EVEN FURTHER. THE ERN
CWA SHOULD BE MOSUNNY WITH DOWNSLOPE FLOW/MINIMAL OVERWATER
TRAJECTORY OF THE DRY AIRMASS. NEAR THE WI BORDER...SOME BREAKS IN
THE SC OVC ARE LIKELY BY MID/LATE AFTN WITH THE CLOSER APRCH OF THE
SFC RDG AXIS. BUT EVEN WHERE THE SUN COMES OUT...HI TEMPS WL BE HARD
PRESSED TO RISE OUT OF THE TEENS PER OBSVD HI TEMPS IN ONTARIO YDAY.
TNGT...AS THE SFC RDG AXIS SHIFTS TO THE E AND THE SHRTWV NOW OVER
WRN CANADA DIGS THRU SCENTRAL CANADA TOWARD THE UPR LKS...THE LLVL
FLOW WL TURN TO THE SSW. FCST SDNGS INDICATE ANY LINGERING LO CLDS
WL DSPT OR SHIFT OUT INTO LK SUP AND GIVE WAY TO A PERIOD OF MOCLR
CONDITIONS BEFORE CLDS ASSOCIATED WITH ISENTROPIC ASCENT AHEAD OF
THE APRCHG CLIPPER SHRTWV INVADE THE AREA NW TO SE. COMBINATION OF
EARLIER ARRIVING CLDS/STRENGTHENING SSW WIND WL TEND TO LIMIT THE
DIURNAL TEMP FALL OVER THE W. BUT OVER THE E...EXPECT TEMPS TO FALL
TOWARD THE LO END OF GUIDANCE BEFORE THE LATER ARRIVAL OF HI CLDS
AND STRENGTHENING FLOW OFF LK MI TENDS TO STOP THE TEMP FALL. THE
BULK OF THE MODELS ARE STILL HINTING THE LEADING EDGE OF THE WAA SN
WL REACH THE WRN CWA BY 12Z MON...SO RETAINED SOME CHC POPS THERE
LATE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM EST SUN JAN 25 2015
EXPECT NO SIGNIFICANT PATTERN CHANGES THROUGH THE PERIOD...AS A
500MB TROUGH LINGERS ACROSS EASTERN CANADA AND MUCH OF THE EAST HALF
OF THE U.S. THE MAIN EXCEPTION WILL BE TUESDAY THROUGH WEDNESDAY AS
THE RIDGE ACROSS THE WEST MOVES ACROSS THE PLAINS AND GREAT LAKES
REGION. BY 00Z THURSDAY 850MB TEMPS SHOULD WARM TO -4 TO -1C
/WARMEST OFF THE 24/12Z ECMWF/. SFC TEMPS TOPPING OUT NEAR FREEZING
WILL BE THE RESULT WEDNESDAY AFTERNOON. THE WARM SPELL WILL BE SHORT
LIVED AS COLDER AIR SET UP OVER N CENTRAL CANADA SHIFTS SINKS ACROSS
HUDSON BAY ON FRIDAY...AND SURGE ACROSS ONTARIO AND INTO THE UPPER
GREAT LAKES FROM SATURDAY THROUGH THE START OF THE NEXT WORK WEEK.
THE EXACT TIMING...SATURDAY OR LATER SATURDAY NIGHT...IS STILL IN
QUESTION. THE 25/00Z IS A LITTLE SLOWER TO PUSH THE COLD AIR DOWN.
GIVEN THAT THIS IS OVER 150HRS OUT...WILL GO WITH A BLENDED SOLUTION
FOR NOW.
AS FOR SOME OF THE SPECIFICS...WE WILL START 12Z MONDAY WITH THE
NEXT LOW KNOCKING ON THE DOOR /SET UP ACROSS SE MANITOBA THROUGH N
MN/. THE CANADIAN AND ECMWF ARE ON THE SW END OF THE LOW TRACK
ENVELOPE...WHILE THE NAM AND GFS ARE FARTHER TO THE NE AND TRACK IT
OVER W LAKE SUPERIR BY 00Z TUESDAY. EITHER WAY THE ROUGHLY 150 MILE
DIFFERNECE IN PLACMENT OF THE LOW DOES MAKE A DIFFERENCE IN THE WIND
FIELDS...BUT BOTH INDICATE SNOW FOR WESTERN AND AT LEAST MOST OF
CENTRAL UPPER MI. THIS SW TREND IN THE BETTER FORCING OCCURRED WITH
THE LAST SIGNIFICANT CLIPPER SYSTEM TOO...SO WE WILL SEE IF THIS
CONTINUES. WILL KEEP THE LIKELY POPS IN THE W ONLY.
BEHIND THE LOW A SFC RIDGE WILL SLIDE ACROSS UPPER MI FROM THE
W...AS THE NEXT LOW ORGANIZES ACROSS THE PLAINS STATES
TUESDAY/WEDNESAY. EXPECT THIS LOW /EXTENDING FROM ND ALL THE WAY
THROUGH N TX AT 18Z WEDNESDAY TO PUSH ACROSS FAR S LAKE MI BY
DAYBREAK THURSDAY. THERE IS AMAZING CONSISTANCY WITH THE TRACK AND
STRENGTH OF THIS LOW FOR THIS 108HR FCST. THE INVERTED TROUGH WILL
EXTEND ALL THE WAY THROUGH N LAKE SUPERIOR 00-12Z THURSDAY. THIS
WILL BE THE FOCUS FOR SNOW...ASSISTED BY THE NEXT ELONGATED
SHORTWAVE SWINGING IN FROM THE NW. AT THIS POINT THE GFS IS HINTING
IN 3-5IN OF SNOW FROM 00Z THURSDAY THROUGH 00Z FRIDAY...BEFORE THE
INVERSION HEIGHTS START DROPPING BELOW 5KFT AS STRONG HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1225 AM EST SUN JAN 25 2015
A MOIST NE LOW-LVL WIND DIRECTION OVER THE AREA SHOULD MAINTAIN MVFR
CIGS THROUGH MUCH OF THE PD FOR ALL TAF SITES. NE WIND DIRECTION WILL
FAVOR MAINLY KSAW FOR LIGHT LAKE EFFECT SNOW SHOWERS INTO SUNDAY BUT
DO NOT EXPECT MUCH VSBY RESTRICTION FROM -SHSN. EXPECT WINDS TO GO
VARIABLE AT KIWD AND KCMX LATE SUNDAY AND AT KSAW TOWARD SUN EVENING
WITH IMPROVEMENT TO VFR CONDITIONS AS HIGH PRES BUILDS IN FM NW OF
LAKE SUPERIOR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 352 AM EST SUN JAN 25 2015
N TO NE WINDS UP TO 20-25 KTS THIS MORNING WILL DIMINISH THIS
AFTERNOON WITH ARRIVAL OF A HI PRES RIDGE. AS THE HI SHIFTS TO THE E
AND A LO PRES APPROACHES FROM THE NW TONIGHT AND MON...EXPECT
INCREASING S WINDS UP TO 25-30 KTS ON MON...STRONGEST OVER THE E
HALF OF THE LAKE. WINDS WILL THEN DIMINISH TO UNDER 20 KTS ON TUE
AND TUE NIGHT AS THE WEAKENING LO SLIDES TO THE SE AND A TRAILING HI
PRES RIDGE MOVES THRU THE UPPER LAKES. LIGHT S WINDS IN THE WAKE OF
THE DEPARTING HI ON WED WILL GIVE WAY STRENGTHENING N WINDS UP TO 25-
30 KTS ON THU FOLLOWING THE PASSAGE OF A LO PRES THRU THE LOWER
LAKES. THE ARRIVAL OF MUCH COLDER AIR AND INCREASING WAVES WILL
LIKELY RESULT IN SOME HEAVY FREEZING SPRAY BY LATE THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1142 PM CST Sat Jan 24 2015
.UPDATE:
Issued at 1133 PM CST Sat Jan 24 2015
Updated lows as clouds and southwest winds have kept temperatures
from dropping as much. Lows to be in the mid 30s to mid 40s.
Byrd
Issued at 835 PM CST Sat Jan 24 2015
The radar was showing relatively weak reflectivities across
southwest IA, northeast KS, and into extreme northwest MO this
evening. Some of this light rain was evaporating before making it
to the ground due to an initially dry surface/boundary layer. This
rain was ahead of an approaching shortwave over southeast SD and a
weaker shortwave over eastern KS. This light rain should spread
into portions of northeast and central MO around midnight per the
latest HRRR model run. The latest NAM model run appears a little
deficient in its QPF tonight across MO. The light rain will spread
southeastward into much of the rest of our forecast area late
tonight/early Sunday morning as the main shortwave amplifies into
an upper level low and the surface low now over northwest IA and
southwest MN drops southeastward to just west of UIN by 12z
Sunday. Low temperatures tonight will be well above normal for
late January due to the lowering and thickening cloud cover along
with southwesterly surface winds for much of our area for most of
the remainder of tonight.
GKS
&&
.SHORT TERM: (Through Late Tonight)
Issued at 322 PM CST Sat Jan 24 2015
Elongated shortwave extending from Saskatchewan southeast into
Montana will dive southeast into Missouri by late tonight. The
associated low level circulation will drive southeast across Iowa
tonight and into extreme northeast Missouri by 12Z. All models are
printing out fairly widespread/light QPF ahead of the shortwave
along and north of the I-44 corridor from the Ozarks north to the
I-70 corridor. Another area of light QPF is showing up over
northern Missouri closer to the low level circulation. GFS and NAM
show a pretty broad area of 850-500mb omega ahead of the shortwave,
and a band of 850mb moisture convergence which sweeps through
Missouri into western Illinois ahead of the 850mb cold front. These
features appear to be the primary drivers for precipitation
tonight. 4KM ARW and NMM WRF members develop a broad area of
simulated reflectivity across the aforementioned parts of the CWFA
and MOS PoPs are likely to categorical in these areas as well.
Given all this, have increased PoPs from I-44 north to Quincy to
likely or better late tonight...with much of southwest Illinois east
of the STL Metro still staying in the high chance category. Kept
temperatures pretty mild in the mid 30s to near 40 with clouds and
southwest flow.
Carney
.LONG TERM: (Sunday through Next Saturday)
Issued at 322 PM CST Sat Jan 24 2015
(Sunday-Tuesday)
Over the last few days the synoptic guidance has been trending a bit
stronger/a bit more southwesterly with Sunday`s clipper system.
12z guidance has also followed this trend, with associated MOS also
indicating a sizeable jump in PoPs as well for the day on Sunday.
It would appear that band of rain that develops overnight will sweep
east into southern/eastern sections of the CWA early Sunday, along
and east of system`s cold front and in area of strong UVV with
initial shot of vorticity with upper system. This area of rain
will be followed by additional pockets of precip sprialling around
the upper low as it works into southern Illinois during the day.
While 850mb temps drop fairly quickly (model consensus indicates
0C isotherm will advect into southern sections of the CWA by
18z), forecast sounding from both NAM and GFS indicate cooling of
low level AMS and the drop of the freezing level to support snow
will be much slower than suggested by 850 mb temps alone. This
makes sense given the strong low level warming that should occur
ahead of the clipper later tonight and into early Sunday. Started
a changeover to snow in our far north by mid morning, with the
changeover dipping into the Ozarks in MO and to near the I70
corridor in IL by 00z Monday. Given how warm we are getting today
and the fact that it appears that the precip will be fairly light
once the changeover to snow occurs, it appears that any
accumulations will be quite minor...generally less than one-half
an inch and primarily near/east of the UIN area.
Precip in the form of light rain and light snow will wind down
across southeast sections of the CWA Sunday evening, with the quick
shot of cold air in the wake of the Clipper dropping temps into the
lower to middle 20s.
All of the 12z guidance indicates a very rapid rebound in temps on
Monday as the upper ridge over the Rockies begins to build into the
Plains. 30s will linger over our eastern counties but 40s seem
likely for areas along and west of the Mississippi...with some
locations in mid MO possibly pushing the 50 degree mark.
Shortwave partially driving Monday`s moderation will drop into the
east coast trof Monday night, with the CAA in the wake of the
shortwave allowing a weak cold front to drop into the mid
Mississippi Valley. However, greatest push of cold air will be well
east of our CWA, so Tuesday`s temps should be in the 40s over
most of the FA.
(Wednesday-Saturday)
Unseasonably warm airmass over the Plains should work its way east
at midweek as the UA pattern over the CONUS becomes progressive and
upper ridge works into the mid-Mississippi Valley. Given the
intensity of the warm air have gone a bit above initialization
numbers with a few locastion in mid MO pushing 60.
Next system in the increasingly active flow regime passes through
the area on Wednesday night. Cold air in the wake of the system
should return temps to more normal levels on Thursday, with temps
dropping a few more degrees on Friday.
While medium range solutions are in very good agreement into
Friday, they diverge considerably heading into the end of the
week. Both GFS and ECMWF develop a cut-off low over the southwestern
U.S. but mid level flow over the central CONUS varies considerably,
with GFS indicating a nearly zonal flow regime from the Rockies
into the east coast while the ECMWF suggests trof deepening over
the eastern half of the country...a much colder solution for our
area by next Saturday (ECMWF 850mb temps are about 10 degrees
colder than those of the GFS). For now have leaned towards the
warmer GFS, with a chance of rain or snow as broad overrunning is
progged across the region.
Truett
&&
.AVIATION: (For the 06z TAFs through 06z Sunday Night)
Issued at 1133 PM CST Sat Jan 24 2015
Surface low over south central Iowa to continue tracking southeast
through forecast area during forecast period. Cigs to gradually
lower as system approaches with MVFR cigs/vsbys expected with
onset of main area of rain...between 11z and 14z Sunday. Will see
dry slot move into KCOU and metro area tafs by mid morning, so
kept vcsh mention. As for KUIN, they will remain mvfr and actually
lower to ifr as they are closer to track of surface low, lifting
back to mvfr by this evening. Then as colder air filters in this
afternoon, rain to pickup and become mixed with snow before coming
to an end this evening. Cigs to remain mvfr through rest of
forecast period. As for winds, southwest winds to veer to the west
then north and become gusty to around 25kts at times. North winds
to diminish by this evening but remain around 10 kts.
Specifics for KSTL:
Surface low over south central Iowa to continue tracking southeast
through forecast area during forecast period. Cigs to gradually
lower as system approaches with MVFR cigs/vsbys expected with
onset of main area of rain...by 14z Sunday. Will see
dry slot move into metro area tafs by 17z Sunday, so kept vcsh mention.
Then as colder air filters in this afternoon, rain to pickup and
become mixed with snow before coming to an end this evening. Cigs
to remain mvfr through rest of forecast period. As for winds,
southwest winds to veer to the west then north and become gusty to
around 25kts at times by 21z Sunday. North winds to diminish by this
evening but remain around 10 kts.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1137 PM CST Sat Jan 24 2015
.UPDATE...
Issued at 831 AM CST SAT JAN 24 2015
First round of rain is coming in a bit heavier than previously
thought and has been able to penetrate dry air at the surface. Still,
upstream observations indicate only one or two hundredths of an inch
of rain will fall from this activity, if that. Could see light rain
or sprinkles make it as far east as central MO later this evening.
Temperatures further upstream across Nebraska and the Dakotas are
warmer than many models had indicated. Near-term models such as the
RAP and HRRR seem to have a better grasp on this, so these were used
to update temperatures overnight and into Sunday morning which do not
appear as supportive of snow over northern MO. Still could see a few
flakes across these areas especially after 10 AM or so.
&&
.DISCUSSION...
Issued at 252 PM CST SAT JAN 24 2015
Tonight/Sunday...Confidence remains for chances of light
precipitation to overspread portions of the forecast area tonight
through Sunday. As of early this afternoon, water vapor imagery
showed a shortwave trough over eastern Montana into the western
Dakotas. This upper disturbance will rapidly drop southeastward,
reaching our forecast area by sunrise Sunday, and remain the
catalyst for the uptick in active weather during the next 24 hours.
Initial precipitation may develop in advance of strong PVA over east
central Kansas, sliding into west central Missouri before expanding
in coverage to the east. An additional area may also be initially
focused closer to the surface low pressure in northeast Missouri.
The initial coverage of precipitation prior to 09-12Z may be
somewhat spotty, with all precipitation falling in the form of rain,
per forecast soundings showing a notable warm layer several kft
above the surface. As the upper disturbance moves through with the
remaining area of deep ascent, a broader area of light precipitation
is expected to move through the region beginning Sunday morning. The
best chances will be across the northeast half of the CWA, with
decreasing chances with southwest extent. Upon the cold frontal
passage, colder air will advect into the area. Forecast soundings
show a cold/saturated enough profile to support snow or a mix of
rain/snow over portions of northern and northeastern Missouri during
the day on Sunday. Where snow can occur, considering light/meager
snow rates, relatively warm ground temperatures, and 2m air
temperatures above freezing, little to no accumulation is expected,
with any dusting reserved for grassy, insulated-type surfaces. All
precipitation is expected to exit from west to east by sunset Sunday.
The cooler weather on Sunday will be short-lived as the upper
pattern remains highly amplified, with a large ridge over the
Intermountain West Monday into Tuesday. Warm H85 temperatures on the
order of 10-13C will overspread much of the Central Plains Monday
through Wednesday, yielding afternoon high temperatures well above
seasonal levels for the region. The warmest day for the forecast
area should occur on Wednesday ahead of the next cold front as the
upper pattern begins to break down, with highs in the middle 50s to
lower 60s. Otherwise, cooler weather is expected to through the
remainder of the work week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1136 PM CST SAT JAN 24 2015
First round of rain moving through the region will taper off over the
next few hours. Ceilings and visibilities remain well into VFR so the
only significant impacts will be runway wetting. A lull is expected
later tonight followed by another round of lighter rain Sunday
morning, especially across northern and northeast MO. Could see a few
snowflakes Sunday afternoon toward IRK. Bigger concern will be winds
which could gust higher than 30kts at times Sunday morning.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Hawblitzel
DISCUSSION...Blair
AVIATION...Hawblitzel
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1144 PM CST SAT JAN 24 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 324 PM CST SAT JAN 24 2015
STRONG SHORTWAVE BRINGING COLDER TEMPERATURES AND A CHANCE FOR RAIN
AND SNOW THROUGH SUNDAY...THEN WARMER TEMPERATURES AGAIN TO START
THE WORK WEEK...REMAIN THE PRIMARY FORECAST CHALLENGES.
STRONG SHORTWAVE WAS NOTED ON WATER VAPOR IMAGERY DIVING THROUGH
EASTERN MONTANA THIS AFTERNOON. RAP ANALYSIS SHOWS 150KT 300MB JET
ACCOMPANYING SHORTWAVE. BOTH FEATURES WILL MOVE TOWARD OUR AREA
LATER THIS EVENING AND PROGRESS TO THE EAST ON SUNDAY. SCATTERED
SHOWERS WERE ALREADY OCCURRING IN WESTERN NEBRASKA CAUSED BY WEAK
VORTICITY LOBE AHEAD OF SHORTWAVE...WITH WING OF WARM ADVECTION
RAIN/SNOW EXTENDING FROM NORTH DAKOTA INTO EASTERN SOUTH DAKOTA
AHEAD OF MAIN SHORTWAVE. COULD SEE ISOLATED SHOWERS/SPRINKLES THIS
EVENING WITH WESTERN NEBRASKA ACTIVITY...BUT MAIN PRECIP CHANCE
WILL COME LATER THIS EVENING WITH NORTHERN PLAINS ACTIVITY. EXPECT
RAIN CHANCES TO INCREASE MARKEDLY BY MIDNIGHT ACROSS ALL OF
EASTERN NEBRASKA AND WESTERN IOWA...WITH LIKELY POPS IN OUR NORTH
WHERE LIFT ASSOCIATED BY MID LEVEL WARM ADVECTION IS MAXIMIZED.
FORECAST SOUNDINGS SUGGEST WARM SURFACE LAYER WILL KEEP PRECIP
LIQUID PAST MIDNIGHT BEFORE LOW LEVEL COLD ADVECTION KICKS
IN...CHANGING RAIN TO SNOW FROM NORTHWEST TO SOUTHEAST. BUT STILL
SURFACE AND BOUNDARY LAYER TEMPERATURES WILL BE SIGNIFICANTLY WARM
TO OFFER DOUBT WHETHER PRECIP WILL CHANGE TO ALL SNOW EXCEPT FOR
NORTHEAST NEBRASKA AND WEST CENTRAL IOWA. WHERE SNOW DOES
FALL...QPF LOOKS TO REMAIN UNDER A TENTH OF AN INCH WITH MELTING
OCCURRING AS WELL. THUS AMOUNTS OF A HALF INCH OR LESS ARE
FORECAST NORTH AND EAST OF THE OMAHA METRO AREA...WITH LITTLE
ACCUMULATION SOUTH AND WEST.
WINDS WILL ALSO KICK UP SIGNIFICANTLY OVERNIGHT...ESPECIALLY IN
NORTHEAST NEBRASKA. UNIDIRECTIONAL NORTHWESTERLY FLOW ACCOMPANIED
BY 50KT 850 JET...ALONG WITH LOW LEVEL INSTABILITY PROMOTING
MIXING OF BOUNDARY LAYER...SUGGEST WINDS OF 30 TO 45 MPH ARE
POSSIBLE BETWEEN MIDNIGHT AND MID SUNDAY MORNING. WILL ISSUE WIND
ADVISORY FOR PARTS OF OUR AREA TO COVER THIS.
PRECIPITATION SHOULD BE ENDING BY NOON SUNDAY...BUT STRONG COLD
ADVECTION WILL PERSIST DURING THE DAY. THUS TEMPERATURES WILL
PROBABLY REMAIN STEADY OF FALL MUCH OF THE DAY. HIGHS ONLY IN THE
30S ARE EXPECTED.
COOLDOWN BEHIND SYSTEM WILL BE BRIEF AS WINDS RETURN TO THE SOUTH OR
SOUTHWEST OVERNIGHT SUNDAY NIGHT AS ANOTHER SHORTWAVE MOVES ACROSS
THE NORTHERN PLAINS. TEMPS MAY RISE OVERNIGHT AFTER AN EVENING
LOW...THEN A WIND SHIFT BEHIND SURFACE TROUGH ASSOCIATED WITH
NORTHERN PLAINS SHORTWAVE WILL OCCUR EARLY MONDAY. GUSTY NORTHWEST
WINDS WILL PROMOTE DECENT MIXING MONDAY AFTERNOON WITH 850
TEMPERATURES IN THE 8-10C RANGE. HIGHS MONDAY AFTERNOON COULD REACH
60 IN OUR SOUTHWEST WITH PLENTY OF 50S ELSEWHERE.
A QUICK SHOT OF HIGH PRESSURE OVERHEAD TUESDAY MORNING WILL MOVE OFF
TO THE EAST...BRINGING SOUTHEASTERLY LOW LEVEL FLOW TUESDAY
AFTERNOON. THIS IS NORMALLY NOT A WARM WIND FOR US...SO TEMPS WILL
BE A GOOD 5 OR 10 DEGREES COOLER TUESDAY AFTERNOON DESPITE A SIMILAR-
TO-MONDAY LOW LEVEL TEMPERATURE PROFILE. STILL SHOULD SEE HIGHS IN
THE 50S MOST AREAS.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 324 PM CST SAT JAN 24 2015
ANOTHER WARM DAY WEDNESDAY WILL BE FOLLOWED BY COOLER TEMPERATURES
THROUGH THE END OF THE WEEK...AND LIKELY SIGNIFICANTLY COLDER BY
NEXT WEEKEND.
UPPER PATTERN WILL BECOME BRIEFLY ZONAL IN THE PLAINS ON WEDNESDAY
AS A PACIFIC SHORTWAVE APPROACHES FROM THE WEST. ANOTHER MILD DAY
WEDNESDAY IS FORECAST AHEAD OF THIS SHORTWAVE WITH SOUTH TO
SOUTHWEST FLOW PUMPING TEMPS BACK INTO THE 50S. SIGNIFICANT COOLING
IS EXPECTED BEHIND THIS WAVE WITH 850 TEMPERATURES DROPPING SOME 20C
BETWEEN WEDNESDAY AND THURSDAY AFTERNOONS. SOME LIGHT PRECIPITATION
IS POSSIBLE...BUT TRACK OF SURFACE LOW WILL BE WELL TO OUR
NORTHEAST. HIGH PRESSURE OVERHEAD THURSDAY WILL KEEP TEMPERATURES
FROM CLIMBING TOO FAR...WITH HIGHS STRUGGLING TO TOP 40. A LITTLE
WARMER FRIDAY AS SOUTH WINDS RETURN BRIEFLY AHEAD OF A STRONG COLD
FRONT DROPPING OUT OF THE NORTHERN PLAINS.
ECMWF AND GFS DIFFER GREATLY FOR FRIDAY NIGHT AND SATURDAY FORECAST.
GFS BRINGS A CLASSIC OVERRUNNING PATTERN TO THE PLAINS WITH
SIGNIFICANT SNOWFALL POSSIBLE. ECMWF KEEPS PRECIPITATION WELL SOUTH
OF OUR AREA AND SLAMS THE PLAINS WITH MINUS 20C 850 AIR. FOR NOW OUR
FORECAST WILL BLEND THESE TWO SCENARIOS WITH COLDER TEMPERATURES AND
A SMALL CHANCE FOR SNOW FRIDAY NIGHT AND SATURDAY.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1140 PM CST SAT JAN 24 2015
LITTLE CHANGE FROM THE PREVIOUS FORECAST. EXPECT VERY WINDY
CONDITIONS THROUGH MID SUNDAY MORNING. CEILINGS ARE BEGINNING TO
FALL ACROSS THE AREA. FOR NOW HAVE MVFR CONDITIONS DOMINATING THIS
FORECAST BUT WOULDN/T BE SURPRISED TO SEE IFR CEILINGS FROM 10-14Z
AT OFK AND OMA. ALSO CAN/T RULE OUT A LIGHT RAIN/SNOW OVERNIGHT
BUT DON/T THINK THESE SHOULD LIMIT VISIBILITY MUCH. BUT THE MAIN
STORY SHOULD BE THE WIND AND LOW CEILING POTENTIAL.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 9 AM CST SUNDAY FOR NEZ011-012-015>018-
030>033-042>044-050-051-065-066-078.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...PEARSON
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1257 AM CST SUN JAN 25 2015
.UPDATE...
ISSUED AT 1257 AM CST SUN JAN 25 2015
AREAS OF PRECIPITATION PERSIST EARLY THIS MORNING ALONG TO EAST OF
AN INVERTED SFC TROUGH STRETCHING FROM EASTERN SOUTH DAKOTA BACK
NORTH-NORTHWEST ACROSS CENTRAL NORTH DAKOTA INTO SOUTHEASTERN
SASKATCHEWAN. EXPANDED POPS TO BETTER REFLECT LATEST RADAR IMAGERY
AND HIGH RES GUIDANCE (HRRR/NAM/RAP)...AND WILL MENTION SOME LOW
POPS 12-15Z SOUTH CENTRAL. PRECIPITATION WILL DIMINISH WITH TIME
THIS MORNING NORTH TO SOUTH AS THE SURFACE TROUGH WASHES OUT AND
FORCING ALOFT DECREASES.
LOW STRATUS CONTINUES TO PUSH SOUTH INTO THE REGION FROM SOUTH
CENTRAL CANADA. LATEST RAP/NAM MAINTAINS THE STRATUS DECK FOR MUCH
OF THE AREA THIS MORNING...THEN ERODES WEST TO EAST DURING THE
AFTERNOON AS OUR WINDS BECOME SOUTHWESTERLY. INCREASED SKY COVER A
BIT TO BETTER REFLECT LATEST MODEL OUTPUT INCLUDING THE
RAP/NAM/HRRR.
WAA TODAY WITH A FEW MODELS GENERATING LIGHT QPF ALONG THE WARM
FRONT. WHILE MOST AREAS LOOK TO REMAIN DRY...OPTED TO THROUGH IN A
SLIGHT CHANCE OF MAINLY LIGHT RAIN AS THE FRONT PUSHES EASTWARD
DURING THE AFTERNOON AND EARLY EVENING.
UPDATE ISSUED AT 931 PM CST SAT JAN 24 2015
AT 914 PM BISMARCK ASOS SURFACE OBS CHANGED TO RAIN FROM SNOW.
DUAL POLE PRODUCTS SUGGEST MIXED PRECIPITATION RAIN AND SNOW AS
THE CORRELATION COEFFICIENT FALLS BELOW 80 IN A NARROW BAND OVER
BISMARCK. ALTHOUGH RAIN...SEE THE VERY END OF THE PRECIPITATION
SHORTLY AS ITS ONLY A BAND ABOUT 10 MILES WIDE. FOR THIS FORECAST
WILL END THE PRECIPITATION SOONER ACROSS THE CENTRAL. WILL
CONTINUE LIGHT SNOW MOST OF THE NIGHT EAST.
UPDATE ISSUED AT 702 PM CST SAT JAN 24 2015
WIND ADVISORY HAS EXPIRED. EMPHASIZED THE EVENING LIGHT SNOW SOUTH
CENTRAL WITH DEFINITE POPS.
UPDATE ISSUED AT 548 PM CST SAT JAN 24 2015
RADAR SHOWS AN AREA OF LIGHT SNOW EXTENDING WEST OF BISMARCK.
BASED ON THIS AND LATEST HRRR RUNS WILL EXTEND THE LIKELY POPS FOR
SNOW WEST THROUGH MORTON COUNTY AND SOUTH TO THE SOUTH DAKOTA
BORDER. WILL LEAVE WIND ADVISORY GOING UNTIL 7 PM AS WINDS CONTINUE
TO GUST OVER 40 MPH AT SAND CREEK RAWS AND HETTINGER.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
AN UPPER LEVEL WAVE CONTINUES TO GENERATE AN AREA OF PRECIPITATION
EXTENDING OVER CENTRAL NORTH DAKOTA. THIS ACTIVITY WILL CONTINUE
TO PIVOT EAST THROUGH TONIGHT. WIND ADVISORY CONDITIONS WILL
CONTINUE OVER SOUTHWESTERN NORTH DAKOTA THROUGH THE REMAINDER OF
THE AFTERNOON AS WELL. THE MAIN FORECAST CHALLENGE WILL BE
DETERMINING THE PRECIPITATION TYPE FOR THE NEXT FEW HOURS.
A COOL CANADIAN AIR MASS CONTINUES TO NOSE INTO NORTH CENTRAL NORTH
DAKOTA THIS AFTERNOON. THIS HAS RESULTED IN ALL SNOW BEING REPORTED
OVER NORTH CENTRAL NORTH DAKOTA. HOWEVER...RELATIVELY WARMER
BOUNDARY LAYER AIR IS GENERATING A NARROW PATCH OF FREEZING RAIN
PRIMARILY OVER JAMESTOWN. AS THE CANADIAN AIR MASS NOSES SOUTH...THE
PRECIP TYPE SHOULD CONTINUE TO TRANSITION FROM RAIN/FREEZING RAIN TO
ALL SNOW OVER THE JAMES RIVER VALLEY BY THIS EVENING.
SNOW WILL LIKELY CONTINUE EAST OF HIGHWAY 83 TONIGHT. BY SUNDAY
MORNING...STORM TOTAL SNOW AMOUNTS SHOULD RANGE BETWEEN 1 AND 2
INCHES ALONG AND EAST OF A LINE FROM MINOT TO STEELE TO ELLENDALE.
AREAS WEST OF SAID LINE SHOULD RECEIVE LESS THAN AN INCH OF NEW SNOW.
LOW PRESSURE MOVING ACROSS SASKATCHEWAN WILL GENERATE DRY AND WARM
SOUTHWESTERLY FLOW OVER WESTERN AND CENTRAL NORTH DAKOTA SUNDAY. DRY
CONDITIONS AND ABOVE NORMAL TEMPERATURES ARE FORECAST. SUNDAY
AFTERNOON HIGHS SHOULD RANGE FROM THE 30S EAST TO THE UPPER 40S
SOUTHWEST.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 245 PM CST SAT JAN 24 2015
...DRY WITH ABOVE NORMAL TEMPERATURES...
AN UPPER LEVEL RIDGE CURRENTLY OVER THE WEST COAST WILL SLOWLY
SHIFT EAST THROUGH THE NEXT COUPLE OF DAYS AND EVENTUALLY CENTER
ACROSS THE PLAINS TUESDAY. WITH PREDOMINATELY WEST WINDS THIS SETUP
WILL ALLOW FOR WELL ABOVE NORMAL TEMPERATURES THROUGH MIDWEEK.
ZONAL FLOW SHOULD THEN DEVELOP THURSDAY...WITH A TRANSITION TO
COOLER NORTHWEST FLOW BY THE WEEKEND. UPPER 40S ARE LIKELY ACROSS
MOST OF WESTERN AND CENTRAL NORTH DAKOTA MONDAY AND TUESDAY WITH
50S LIKELY ACROSS THE SOUTHWEST. BY THE WEEKEND ARCTIC AIR MAY
MAKE A RETURN TO THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1257 AM CST SUN JAN 25 2015
FAST MOVING LOW PRESSURE ACROSS THE EASTERN DAKOTAS WILL MOVE
SOUTHEAST TONIGHT. AN EXTENSIVE AREA OF MVFR TO IFR STRATUS WILL
REMAIN OVER THE STATE IN ITS WAKE. SNOW WITH OCCASIONAL IFR
CONDITIONS WILL PREVAIL FROM KMOT-KBIS-KJMS THROUGH 09-12Z THEN
SLOWLY IMPROVE BUT MVFR STRATUS WITH POCKETS OF IFR WILL PERSIST
THROUGH THE MORNING. CONDITIONS IMPROVE WEST TO EAST DURING THE
AFTERNOON...WITH LATEST MODELS NOW INDICATING ANOTHER LOW STRATUS
FIELD MOVING INTO WESTERN NORTH DAKOTA LATE SUNDAY INTO SUNDAY
EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...TM
LONG TERM...AJ
AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1132 PM CST SAT JAN 24 2015
.UPDATE...
ISSUED AT 1133 PM CST SAT JAN 24 2015
CURRENT RADAR SHOWS BEST REFLECTIVITIES ALONG ROUGHLY A BOTTINEAU
TO RUGBY TO HARVEY TO STEELE LINE...WITH LESSER RETURNS OVER MOST
OF SOUTHEASTERN ND. WE ARE GETTING GROUND TRUTH IN THE SOUTHWEST
BUT NORTHERN VALLEY ECHOES ARE CLOUDS ONLY...AS NORTHEAST FLOW IS
KEEPING BNDRY LYR DRY. 02Z RUC NICELY DEPICTS THE EASTWARD EXTENT
OF THE SNOW...WHICH IS BEING HAMPERED BY THE NE FLOW. HAVE UPDATED
POPS WITH RUC GUIDANCE AND MADE SOME ADJUSTMENTS IN THE SRN
VALLEY...WHERE RUC WAS A BIT LOW WITH POPS. CONTINUE TO EXPECT
MOST OF NORTHEASTERN QUARTER OF CWA TO RECEIVE LITTLE IF NO
SNOWFALL TONIGHT...AND ONE TO TWO INCHES IN PORTIONS OF EAST
CNTRL AND SOUTHEASTERN ND.
UPDATE ISSUED AT 655 PM CST SAT JAN 24 2015
CURRENT FORECAST LOOKS ON TRACK...LIGHT SNOW FALLING OVER WEST
CENTRAL AND SOUTHWESTERN PORTIONS OF CWA...WITH SOME OBS OF RAIN
IN CNTRL ND EARLIER ON...WHICH HAS NOW CHANGED TO SNOW. MAIN
ISSUE TO WATCH TONIGHT IS EASTWARD EXTENT OF SNOW...AS CURRENT POP
GRIDS KEEP LIKELIES JUST WEST OF GRAND FORKS AND DO BRING IT IN TO
THE FARGO AREA. WILL HOLD OFF ON ANY ADJUSTMENTS UNTIL 00Z NAM
COMES IN AS FCST IN PRETTY GOOD SHAPE RIGHT NOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 253 PM CST SAT JAN 24 2015
MAIN FORECAST CHALLENGE WILL BE THE BAND OF PCPN MOVING THROUGH
THE AREA LATE THIS AFTERNOON/TONIGHT. 12Z MODEL RUNS CONTINUED TO
PUSH BACK WESTWARD WHERE THIS BAND WILL FALL AND IT APPEARS THAT
SOME OF THE 18Z GUIDANCE MAY BE EVEN LIGHTER WITH THE EXPECTED
AMOUNTS. AS OF MID AFTERNOON MOST OF THE LIGHT PCPN WAS FALLING
BETWEEN KMOT AND KJMS AND WAS SLIDING SE. SOME OF THIS LIGHT PCPN
DID EXTEND INTO THE FAR WESTERN FA. LOOKING AT SFC TEMPS...THEY
WERE 30F AT KDVL AND 32F AT KJMS AND 37F AT GWINNER. SFC OBS WERE
REPORTING LIGHT SNOW AT CARRINGTON AND FZDZ/LIGHT SNOW AT KJMS
WITH THE WARMEST SFC AIR AT GWINNER (ALTHOUGH NO PCPN YET). WITH
THE CONTINUED COOL ADVECTION LATE THIS AFTERNOON AND TONIGHT ANY
MIX ACROSS THE SW FA WILL BE BRIEF. 18Z NAM COMING IN EVEN WEAKER
WITH EXPECTED SNOW AMOUNTS...WITH LESS THAN INCH ACROSS THE WEST
AND A DUSTING CLOSER TO THE RED RIVER VALLEY. ALL SAID THIS EVENT
IS MUCH WEAKER AND FURTHER WEST THAN EXPECTED. WILL KEEP SOME
MINIMAL CHANCES FOR LIGHT SNOW ACROSS MAINLY THE SOUTH ON SUNDAY
MORNING BEFORE THE SYSTEM EXITS OFF TO THE SE. ANOTHER WEAK LIGHT
SNOW PRODUCING SYSTEM WILL AFFECT THE NORTHEAST FA BEGINNING SUN
NIGHT. AS THE SFC LOW PASSES TO THE NORTH AND EAST...PRETTY DECENT
WARMING OCCURS AGAIN. THEREFORE COULD EASILY SEE RISING TEMPS
SUNDAY NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 253 PM CST SAT JAN 24 2015
WILL LINGER THE LIGHT SNOW CHANCES IN THE NORTHEAST FA ON MONDAY.
WEST TO NW WINDS CONTINUE ON MONDAY WITH VERY MILD AIR MOVING BACK
IN. KEPT HIGHS ON MONDAY ABOVE GUIDANCE TEMPS. STAYS QUIET MON
NIGHT INTO TUE. MUCH LIGHTER SFC WINDS ON TUE MAY KEEP TEMPS DOWN
A LITTLE BUT MORE LIKELY WILL DEPEND ON CLOUD COVER. EITHER WAY
WILL STICK WITH MILD TEMPS INTO TUE.
FOR TUE NIGHT THROUGH SAT...THE BEGINNING OF THE EXTENDED WILL START
OUT WARM WITH TEMPS ABOVE NORMAL. THERE COULD BE SOME LIGHT SNOW WED
NIGHT BEHIND A COOL FRONT...THEN AGAIN TOWARDS THE END OF NEXT WEEK.
A MORE SIGNIFICANT COLD FRONT IS PROGGED BY NEXT SAT...THAT COULD
MEAN AN END TO THE MILD TEMPS WE HAVE SEEN RECENTLY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1133 PM CST SAT JAN 24 2015
NORTHEAST FLOW SET UP AT DVL AND CIGS HAVE RISEN INTO UPPER MVFR
RANGE...WITH ALL OTHER SITES IN THE VALLEY AND NORTHWEST MN VFR.
WILL LIKELY SEE SOME FLURRIES OR LIGHT SNOW AT DVL...MORE LIKELY
AT FAR...THAT COULD BRING VSBYS INTO THE 3 SM TO 5 SM RANGE. OTHER
THAN THAT...LOW VFR DECK WILL PERSIST THROUGH EARLY SUN AFTN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...GODON
LONG TERM...GODON/DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1006 PM CST SAT JAN 24 2015
.UPDATE...
ISSUED AT 1006 PM CST SAT JAN 24 2015
CURRENT RADAR SHOWS BEST REFLECTIVITIES ALONG ROUGHLY A BOTTINEAU
TO RUGBY TO HARVEY TO STEELE LINE...WITH LESSER RETURNS OVER MOST
OF SOUTHEASTERN ND. WE ARE GETTING GROUND TRUTH IN THE SOUTHWEST
BUT NORTHERN VALLEY ECHOES ARE CLOUDS ONLY...AS NORTHEAST FLOW IS
KEEPING BNDRY LYR DRY. 02Z RUC NICELY DEPICTS THE EASTWARD EXTENT
OF THE SNOW...WHICH IS BEING HAMPERED BY THE NE FLOW. HAVE UPDATED
POPS WITH RUC GUIDANCE AND MADE SOME ADJUSTMENTS IN THE SRN
VALLEY...WHERE RUC WAS A BIT LOW WITH POPS. CONTINUE TO EXPECT
MOST OF NORTHEASTERN QUARTER OF CWA TO RECEIVE LITTLE IF NO
SNOWFALL TONIGHT...AND ONE TO TWO INCHES IN PORTIONS OF EAST
CNTRL AND SOUTHEASTERN ND.
UPDATE ISSUED AT 655 PM CST SAT JAN 24 2015
CURRENT FORECAST LOOKS ON TRACK...LIGHT SNOW FALLING OVER WEST
CENTRAL AND SOUTHWESTERN PORTIONS OF CWA...WITH SOME OBS OF RAIN
IN CNTRL ND EARLIER ON...WHICH HAS NOW CHANGED TO SNOW. MAIN
ISSUE TO WATCH TONIGHT IS EASTWARD EXTENT OF SNOW...AS CURRENT POP
GRIDS KEEP LIKELIES JUST WEST OF GRAND FORKS AND DO BRING IT IN TO
THE FARGO AREA. WILL HOLD OFF ON ANY ADJUSTMENTS UNTIL 00Z NAM
COMES IN AS FCST IN PRETTY GOOD SHAPE RIGHT NOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 253 PM CST SAT JAN 24 2015
MAIN FORECAST CHALLENGE WILL BE THE BAND OF PCPN MOVING THROUGH
THE AREA LATE THIS AFTERNOON/TONIGHT. 12Z MODEL RUNS CONTINUED TO
PUSH BACK WESTWARD WHERE THIS BAND WILL FALL AND IT APPEARS THAT
SOME OF THE 18Z GUIDANCE MAY BE EVEN LIGHTER WITH THE EXPECTED
AMOUNTS. AS OF MID AFTERNOON MOST OF THE LIGHT PCPN WAS FALLING
BETWEEN KMOT AND KJMS AND WAS SLIDING SE. SOME OF THIS LIGHT PCPN
DID EXTEND INTO THE FAR WESTERN FA. LOOKING AT SFC TEMPS...THEY
WERE 30F AT KDVL AND 32F AT KJMS AND 37F AT GWINNER. SFC OBS WERE
REPORTING LIGHT SNOW AT CARRINGTON AND FZDZ/LIGHT SNOW AT KJMS
WITH THE WARMEST SFC AIR AT GWINNER (ALTHOUGH NO PCPN YET). WITH
THE CONTINUED COOL ADVECTION LATE THIS AFTERNOON AND TONIGHT ANY
MIX ACROSS THE SW FA WILL BE BRIEF. 18Z NAM COMING IN EVEN WEAKER
WITH EXPECTED SNOW AMOUNTS...WITH LESS THAN INCH ACROSS THE WEST
AND A DUSTING CLOSER TO THE RED RIVER VALLEY. ALL SAID THIS EVENT
IS MUCH WEAKER AND FURTHER WEST THAN EXPECTED. WILL KEEP SOME
MINIMAL CHANCES FOR LIGHT SNOW ACROSS MAINLY THE SOUTH ON SUNDAY
MORNING BEFORE THE SYSTEM EXITS OFF TO THE SE. ANOTHER WEAK LIGHT
SNOW PRODUCING SYSTEM WILL AFFECT THE NORTHEAST FA BEGINNING SUN
NIGHT. AS THE SFC LOW PASSES TO THE NORTH AND EAST...PRETTY DECENT
WARMING OCCURS AGAIN. THEREFORE COULD EASILY SEE RISING TEMPS
SUNDAY NIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 253 PM CST SAT JAN 24 2015
WILL LINGER THE LIGHT SNOW CHANCES IN THE NORTHEAST FA ON MONDAY.
WEST TO NW WINDS CONTINUE ON MONDAY WITH VERY MILD AIR MOVING BACK
IN. KEPT HIGHS ON MONDAY ABOVE GUIDANCE TEMPS. STAYS QUIET MON
NIGHT INTO TUE. MUCH LIGHTER SFC WINDS ON TUE MAY KEEP TEMPS DOWN
A LITTLE BUT MORE LIKELY WILL DEPEND ON CLOUD COVER. EITHER WAY
WILL STICK WITH MILD TEMPS INTO TUE.
FOR TUE NIGHT THROUGH SAT...THE BEGINNING OF THE EXTENDED WILL START
OUT WARM WITH TEMPS ABOVE NORMAL. THERE COULD BE SOME LIGHT SNOW WED
NIGHT BEHIND A COOL FRONT...THEN AGAIN TOWARDS THE END OF NEXT WEEK.
A MORE SIGNIFICANT COLD FRONT IS PROGGED BY NEXT SAT...THAT COULD
MEAN AN END TO THE MILD TEMPS WE HAVE SEEN RECENTLY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 655 PM CST SAT JAN 24 2015
NORTHEAST FLOW WILL HELP KEEP CIGS MVFR AT BJI AND TVF...AND
EVENTUALLY GFK. MAIN ISSUE WILL BE MVFR CIGS...INTERMITTENTLY
IFR...WITH LIGHT SNOW OVER FAR/DVL TONIGHT. CLIPPER SYSTEM WILL
MOVE INTO MO BY 12Z AND MOST PRECIP ON NORTH EDGE SHOULD CLEAR THE
SRN RRV BY MID MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...SPEICHER
SHORT TERM...GODON
LONG TERM...GODON/DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1244 AM EST SUN JAN 25 2015
.SYNOPSIS...
AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF PENNSYLVANIA SUNDAY
NIGHT WITH ANOTHER WEAKER CLIPPER TAKING THE SAME PATH MONDAY
NIGHT AND EARLY TUESDAY. HIGH PRESSURE WILL BUILD OVER THE REGION
MID WEEK...FOLLOWED BY ANOTHER CLIPPER LATE THURSDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
HAVE CANCELLED THE FREEZING RAIN ADVISORY FROM CLEARFIELD CO
NORTHWARD...WHERE ARRIVAL OF DEEPER MOISTURE HAS CHANGED PRECIP TO
-SHSN. HOWEVER...LATEST NAM AND RAP SOUNDINGS INDICATE CLOUD TOP
TEMPS WILL REMAIN ABV -10C ACROSS THE LAURELS...SO ANTICIPATE A
CONTINUATION OF THE -FZRA/FZDZ DOWN THERE FOR MOST OF THE NIGHT.
A CALL TO SOMERSET CO PENNDOT AT 05Z CONFIRMS THAT ROADS ARE ICY
DOWN THERE.
THE SNOW SHOWERS IN THE N/W SHOULD ONLY AMOUNT TO AN INCH OR SO
OVERNIGHT. UNDER OVERCAST SKIES...TEMPS WILL NOT DROP MUCH THRU
THE NIGHT. WINDS WILL BE GUSTY AS THE GRADIENT REMAINS TIGHT.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM MONDAY/...
LITTLE CHANGE FROM PREVIOUS EXPECTED ON SUNDAY. SOME LIGHT
OROGRAPHIC SNOW MAY BE ONGOING SUNDAY MORNING ACROSS THE LAUREL
HIGHLANDS. WILL CONTINUE TO FOCUS ON THE APPROACHING POTENT
CLIPPER WHICH PROMISES TO BRING ANOTHER LIGHT TO LOCALLY MODERATE
SNOW ACCUMULATION. THIS TIME IT IS THE LAURELS AND SC MOUNTAINS
MOST SHARPLY FOCUSED IN ITS CROSS HAIRS FOR SUNDAY NIGHT INTO
MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
CLIPPER WILL BRING SOME SNOW TO THE AREA LATE SUNDAY AFT INTO
MONDAY MORNING. ENERGY WILL QUICKLY TRANSFER TO THE COASTAL LOW
DURING THE DAY ON MONDAY. EXPECT THE HEAVIEST SNOW ACROSS THE
SOUTH CENTRAL PART OF THE STATE...GIVEN NW TO SE WARM FRONT.
THUS LAUREL HIGHLANS WILL LIKELY SEE HIGHEST AMTS.
DID EDGE POPS AND AMTS UP A LITTLE ACROSS THE SE...TO FIT
IN BETTER WITH LWX.
ALSO DID UP POPS ON TUESDAY. CONCERN IS THAT INVERTED
TROUGH COULD KEEP SNOW ACROSS THE WEST INTO TUE...AND COASTAL
STORM THAT DEEPENS EXTREMELY FAST MAY WRAP SNOW AROUND TO THE
WEST SIDE...A CONCERN FOR THE EAST AND SE. BLOCKING HIGH TO THE
NORTH.
STILL A LITTLE EARLY FOR AN ADVISORY ACROSS THE SOUTH.
TIGHT TEMP GRADIENT BETWEEN NY AND MD...SOME ADJUSTMENTS TO
TEMPS MONDAY INTO TUE.
WED STILL LOOKS LIKE A DRY DAY.
ANOTHER FRONTAL SYSTEM FOR LATE THU.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
DECK OF LOWER STRATUS ASSOCIATED WITH SHORTWAVE TROF ROTATING
THROUGH BEHIND DEPARTING STORM NOW OVERSPREADING THE REGION WITH
MVFR TO LIFR CONDITIONS. DOWNSLOPING MAY BE ENOUGH TO KEEP
SOUTHEAST AIRFIELDS IN VFR CONDITIONS...BUT ELSEWHERE LOOK FOR
RESTRICTIONS IN CIGS MUCH OF THE OVERNIGHT.
SOME FREEZING DRIZZLE IS NOW BEING PRODUCED OVER THE NORTHWEST
AIRFIELDS...WITH KBFD REPORTING INTERMITTENT -FZRA. THESE
CONDITIONS LIKELY THROUGH 04Z-06Z.
AN ALBERTA CLIPPER WILL TRACK JUST SOUTH OF PENNSYLVANIA SUNDAY
NIGHT INTO MONDAY...BRINGING ANOTHER ROUND OF SNOW WITH IFR
CONDITIONS TO THE REGION. THIS WILL LIKELY IMPACT MOST TAF SITES
AFTER 00Z TOMORROW...BUT SOME AFFECTS POSSIBLE KJST AND KAOO
BEFORE THIS TIME...WHICH IS REFLECTED IN THE TAFS. EXPECT A
PROLONGED PERIOD OF RESTRICTIONS INTO MON NIGHT.
OUTLOOK...
SUN...MVFR TO IFR IN THE WESTERN AND NORTHERN MOUNTAINS...VFR
ELSEWHERE.
SUN NITE...SNOW RAPIDLY OVERSPREADING FROM SW TO NE...BRINGING IFR
CONDITIONS TO THE ENTIRE REGION OVERNIGHT.
MON...WIDESPREAD IFR/MVFR IN SNOW...GRADUAL IMPROVEMENT OVERNIGHT.
TUE...AREAS MVFR IN SHSN WEST...AND ANY LINGERING SNOW IN THE EAST.
WED...NO SIG WEATHER EXPECTED.
THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM
THE WEST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
PAZ024-033.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO/FITZGERALD
SHORT TERM...DEVOIR
LONG TERM...MARTIN
AVIATION...JUNG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1252 AM EST SUN JAN 25 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD BACK INTO THE REGION TODAY...BEFORE ANOTHER
LOW PRESSURE AREA AND TRAILING UPPER LEVEL DISTURBANCE MOVE THROUGH
MONDAY AND TUESDAY. HIGH PRESSURE RETURNS DURING THE LATTER HALF OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1245 AM...STRATOCU ASSOCIATED WITH VERY SHALLOW W/NW FLOW
MOISTURE IS ALREADY MAKING ITS RETREAT INTO SW VIRGINIA AND SE
KENTUCKY. SKY COVER HAS BEEN REDUCED SUBSTANTIALLY ACROSS THE TENN
BORDER COUNTIES FOR THE DURATION OF THE EARLY MORNING. OTHERWISE...
MIN TEMPS SHOULD AVERAGE AROUND NORMAL IN MOST LOCATIONS...ALTHOUGH
PERSISTENT MIXING IN THE MAJOR MTN VALLEYS MAY ACTUALLY YIELD ABOVE
CLIMO MINS. WINDS CONTINUE TO GUST TO 30-40 KTS ACROSS THE NRN
MTNS...MAINLY IN EXPOSED LOCATIONS. HOWEVER...WINDS ARE PROBABLY AT
OR NEAR THEIR PEAK...AS THE FLOW IS ALREADY BACKING IN RESPONSE TO
THE NEXT MAJOR VORT MAX DROPPING OUT OF THE NORTHERN PLAINS. THE
ADVISORY WILL BE ALLOWED TO CONTINUE FOR NOW...BUT THE PLAN IS TO
DROP IT BY 4 AM.
AS OF 1020 PM EST...WINDS HAVE SUDDENLY COME UP STRONGLY BEHIND THE
PASSING APPALACHIANS WAVE...WITH BOONE TO WEST JEFFERSON GUSTING 40
TO 50 KT...AND SOME HIGHER PEAKS FROM MT MITCHELL TO GRANDFATHER
STARTING TO SHOW SOLID ADVISORY VALUES. THE LATEST RAP RUNS HAVE NW
WINDS INCREASING FURTHER THROUGH 06Z...SO A WIND ADVISORY WILL BE
ISSUED FOR THE NRN THREE COUNTIES UNTIL 6 AM...WHEN THE GRADIENT
SHOULD HAVE SLACKENED.
OTHERWISE...A BRIEF PERIOD OF RESIDUAL NW FLOW MOISTURE BEHIND A
SHORTWAVE CROSSING THE APPALACHIANS WILL PEAK AROUND 06Z. ISOLD
LIGHT SNOW SHOWERS OR PATCHY FREEZING DRIZZLE WILL BE POSSIBLE...BUT
CHANCES LOOK TOO SMALL THIS FAR SOUTH OF THE BETTER MOISTURE TO
FEATURE ANY SNOW/ICE AMOUNTS. THE OTHER CONCERN WILL BE FOR VERY
PATCHY BLACK ICE IN LOCATIONS WHERE WET ROADS MIGHT HAVE LINGERED
INTO THE EVENING HOURS FROM EARLY DAY PRECIPITATION. ALTHOUGH THIS
COULD BE A MINOR CONCERN FROM THE NC MTNS TO PARTS OF THE NW
PIEDMONT...THERE APPEARS TO HAVE BEEN JUST ENOUGH DRYING THIS
AFTN/EVENING TO NOT REQUIRE AN SPS. EXPECT OVERNIGHT LOWS AROUND
NORMAL.
SHORT WAVE RIDGING WILL DEVELOP OVER THE AREA SUNDAY AHEAD OF A
STRONG CLIPPER SYSTEM MOVING INTO THE MID MISSISSIPPI VALLEY. LOW
LEVEL FLOW WILL BECOME SLY AHEAD OF THE ASSOCIATED SFC LOW. AFTER
CLEARING SKIES ACROSS THE MTNS DURING THE MORNING AS LOW LEVEL
MOISTURE DEPARTS...CLOUDS MOVE BACK IN IN THE DEVELOPING WAA
PATTERN. ISOLATED SHRA MAY ALSO DEVELOP ACROSS THE MTNS VERY LATE IN
THE DAY AS DEEP MOISTURE INCREASES...BUT NO SIGNIFICANT QPF IS
EXPECTED. CLOUDS WILL INCREASE LATE IN THE DAY OUTSIDE OF THE
MTNS...BUT MOSTLY SUNNY SKIES WILL PREVAIL FOR THE BULK OF THE DAY.
HIGHS WILL BE A FEW DEGREES ABOVE NORMAL ACROSS THE CWFA.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AS OF 230 PM SATURDAY...THE POTENT CLIPPER SYSTEM WILL CROSS THE
CWFA SUNDAY NIGHT THRU MONDAY MORNING PER LATEST CONSENSUS. GUIDANCE
CONTINUES TO BE IN GOOD AGREEMENT ON THE TIMING. BEST Q-VECTOR
CONVERGENCE LOOKS TO BE AROUND 00-06Z MON...SHIFTING EAST BY 12Z.
STEEP LOW-MID LVL LAPSE RATES AND DECENT MOISTURE SHUD RESULT IN
GOOD COVERAGE OF PRECIP ACRS THE HIGH TERRAIN OVERNIGHT...WITH SOME
ACTIVITY BEING ABLE TO DEVELOP EAST OF THE MTNS. WITH MID LVL
THICKNESSES CRASHING...COUPLED WITH WEAK SBCAPE (UP TO 150
J/KG)...MAY SEE CONVECTIVE SNOW SHWRS ACRS THE MTNS. IN THE LWR
ELEVATIONS...ALL INDICATIONS ARE THAT THE SFC-BASED WARM LAYER WILL
PROBABLY JUST BE TOO WARM. IF THE BEST FORCING IS ABLE TO OCCUR
DURING THE WEE MORNING HOURS...CANNOT RULE OUT SPOTTY SNOW SHWRS
ACRS NE GA AND THE WRN UPSTATE. BASED ON CURRENT TIMING...IT LOOKS
LIKE THE NC FOOTHILLS AND PIEDMONT HAVE A BETTER SHOT AT SEEING A FEW
FLAKES...BUT EVEN THERE...NOT EXPECTING ANY WIDESPREAD ACCUMS. EVEN
IN THE MTNS...ACCUMS MAY STRUGGLE TO REACH ADVISORY CRITERIA...AS
LLVL FLOW WILL BE OUT OF THE WEST-SOUTHWEST OVERNIGHT. FOR TEMPS...I
WENT CLOSE TO THE MOS CONSENSUS...MAINLY IN THE UPR 20S TO MID 30S
MTNS AND UPR 30S-40 PIEDMONT.
AS THE MID LVL LOW PASSES TO THE EAST MONDAY MORNING...LLVL FLOW
WILL VEER TO NWLY...BUT NEVER GETS ALL THAT STRONG. SO ONLY LIGHT
ADDITIONAL NW FLOW SNOW ACCUMS ARE EXPECTED ALONG THE TN LINE DURING
THE DAY. EAST OF THE MTNS...FCST SNDGS SHOW LINGERING LLVL MOISTURE
WITHIN WEAK NW FLOW...BUT FORCING SHUD WANE FOR ANY PRECIP. TEMPS
WILL WARM INTO THE MID 30S TO LWR 40S IN THE MTNS...AND UPR 40S TO
LWR 50S ACRS THE PIEDMONT.
MONDAY NIGHT AND TUESDAY...ANOTHER SHORTWAVE WILL DIVE SOUTHEAST
ACRS THE OHIO VALLEY...AND REINFORCE NWLY FLOW ATOP THE CWFA. IN
FACT...THE 12Z NAM AND GFS AGREE ON BETTER OVERALL NW FLOW SETUP
ACRS THE SOUTHERN APPALACHIANS...ESPECIALLY AROUND MIDDAY TUESDAY.
ON THE PLAN VIEW...THE 925-850 MB FLOW ALSO SEEMS TO COME OFF THE
GREAT LAKES TO THE NC MTNS. SO MAY SEE DIURNALLY-ENHANCED CONVECTIVE
SNOW SHWRS DEVELOPING ACRS ERN KY/TN...THEN INTO THE NC
MTNS...PRODUCING A QUICK 1-2" OF SNOW. I WILL PLAN TO ADD A MENTION
OF SNOW ACCUM IN THE HWO ALONG THE TN BORDER FOR TUESDAY.
OTHERWISE...EXPECT GENERALLY MOSTLY CLEAR SKIES AND BELOW NORMAL
TEMPS ACRS THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM SAT...THE PERSISTENT DEEP TROUGH OVER THE ERN SEABOARD
WILL FINALLY MOVE OFF THE EAST COAST WEDNESDAY ALLOWING A SHORT RIDGE
AND HIGH PRESSURE TO BUILD ACROSS THE CWFA. COLD ADVECTION AND MOIST
NW FLOW WILL CONTINUE TUE NIGHT INTO WED...WITH POPS ACCORDINGLY
CONTINUED NEAR THE TENN BORDER. DRY AND SETTLED WEATHER RETURN
BRIEFLY BEFORE THE NEXT CLIPPER MOVES IN LATE THURSDAY. THE CLIPPER
WILL HAVE ABSORBED A WEAK WAVE IN THE SRN STREAM AND IS PROGGED TO
PUSH A WEAK COLD FRONT INTO THE DEEP SOUTH AND CAROLINAS THU NIGHT.
CHC POPS FOR THE UPSLOPE AREAS OF THE MTNS WILL BE ADVERTISED...IN
ADDITION TO SCHC POPS IN THE PIEDMONT AFFORDED BY THE PRESENCE OF
SOME LLVL FORCING. HIGH PRESSURE RETURNS IN THE WAKE OF THE FRONT AS
THE UPPER FLOW BECOMES MORE ZONAL. REGARDING FURTHER EVOLUTION...THE
24/12Z RUNS OF THE GFS AND EC DIVERGE BY THE WEEKEND. EC BRINGS
ANOTHER CLIPPER INTO THE CENTRAL APPALACHIANS BY SATURDAY NIGHT WITH
AN ERN TROUGH DEVELOPING AFTERWARD. GFS IS A BIT MORE ACTIVE WITH THE
SRN STREAM DURING THE SAME PERIOD...SHOWING RETURN FLOW OVER THE HIGH
WHICH DEVELOPS INTO A WEDGE. BOTH MODELS KEEP US DRY THRU SATURDAY
HOWEVER. TEMPS WILL REMAIN IN A SEASONABLE RANGE THRU THE FCST
PERIOD...STARTING OFF A COUPLE DEGREES BELOW NORMALS...BUT WARMING
WED-THU PRIOR TO THE FROPA AND A SUBSEQUENT RETURN OF READINGS A BIT
BELOW NORMAL.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS THROUGH THE PERIOD...
ALTHOUGH SOME VALLEY FOG MAY OCCUR IN THE MTNS WEST OF KAVL LATER
THIS MORNING. LIGHT WSW WINDS ARE EXPECTED TO PERSIST THOUGH THE
OVERNIGHT (NW AT KAVL)...BECOMING SOUTH AT 5-10 KTS DURING THE
AFTERNOON...AHEAD OF THE NEXT COLD FRONT/UPPER AIR DISTURBANCE. VFR
CIGS BETWEEN 050-100 ARE EXPECTED TO OVERSPREAD THE AREA QUICKLY
DURING THE EVENING IN ADVANCE OF THIS SYSTEM. PRECIP CHANCES WILL
ALSO INCREASE BY THE END OF THE PERIOD...MAINLY ACROSS THE MTNS...
BUT WILL WITHHOLD THIS MENTION UNTIL CONFIDENCE IN TIMING INCREASES.
OUTLOOK...A SERIES OF CLIPPER SYSTEMS WILL BRING PERIODIC CHANCES
FOR SNOW SHOWERS...MAINLY TO THE MOUNTAINS THROUGH THE WEEK. MOST OF
THESE SNOW SHOWERS WILL REMAIN WEST AND NORTH OF KAVL...BUT BRIEF
PERIODS OF RESTRICTIONS AND SNOW SHOWERS CANNOT BE RULED OUT THERE.
OTHERWISE...MAINLY VFR CONDITIONS ARE EXPECTED.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 94%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 97%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NCZ033-049-
050.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...HG/JDL/RWH
SHORT TERM...ARK
LONG TERM...WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1039 PM CST SAT JAN 24 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 250 PM CST SAT JAN 24 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SOUTHWARD
MOVING ARCTIC COLD FRONT REACHING THE U.P. BORDER EARLY THIS
AFTERNOON. BEHIND THIS FRONT IS A VERY COLD/DRY AIRMASS AS EVIDENT
BY TEMPS ONLY IN THE SINGLE DIGITS AND DEWPOINTS BELOW ZERO OVER ONTARIO.
THE FRONT IS MAINLY INACTIVE AT THE MOMENT. WEAK SHORTWAVE ACTIVITY
COMBINED WITH UPPER DIVERGENCE IS CONTRIBUTING TO SCATTERED SNOW
SHOWERS AND FLURRIES THAT ARE MOVING ACROSS NORTHWEST AND
NORTH-CENTRAL WISCONSIN. EXPECTATION IS THAT THESE LIGHT SNOW
SHOWERS WILL GRADUALLY DROP SOUTH INTO CENTRAL AND EAST-CENTRAL
WISCONSIN LATER THIS AFTERNOON. FARTHER WEST...A CLIPPER SYSTEM IS
DROPPING SOUTHEAST ACROSS THE NORTHERN PLAINS WITH A DECENT SWATH OF
SNOW OCCURRING OVER NORTH DAKOTA. SNOWFALL POTENTIAL ALONG THE
FRONT AND FROM THE CLIPPER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...AN ARCTIC COLD FRONT WILL BE DROPPING SOUTH ACROSS THE
AREA THIS EVENING WHILE A CLIPPER TRACKS SOUTHEAST ACROSS THE
CENTRAL PLAINS AND INTO THE CENTRAL MISSISSIPPI VALLEY. PERHAPS
COULD SEE A FEW FLURRIES ALONG THE FRONT OVER FAR NORTHERN WISCONSIN
EARLY THIS EVENING...BUT ANTICIPATING BETTER CHANCES OF SNOW TO
OCCUR ALONG THE FRONT AS IT MOVES INTO CENTRAL WISCONSIN AND THE FOX
VALLEY BY MID-EVENING. GUIDANCE IS INDICATING DECENT MID-LEVEL FGEN
DEVELOPING ALONG THE FRONT IN ADDITION TO INCREASING LARGE SCALE
FORCING AHEAD OF THE SHORTWAVE. AS A RESULT...KEPT LOW CHANCE
POPS IN THE FORECAST THERE. STILL ANTICIPATING A GLANCING BLOW FROM
THE CLIPPER SYSTEM AFTER MIDNIGHT...THOUGH THE LATEST RUNS OF
MESOMODELS SUGGEST THE SNOW WILL MISS THE FORECAST AREA ENTIRELY.
AREAS FROM WISC RAPIDS TO WAUTOMA COULD SEE UP TO A HALF INCH...BUT
AMOUNTS WILL BE LESS FARTHER NORTH. WITH THE PASSAGE OF THE
FRONT...NORTHEAST WINDS WILL BECOME GUSTY OVER THE FOX VALLEY AND
LAKESHORE. WOULD NOT BE SURPRISED TO SEE A FEW GUSTS UP TO 30 MPH.
LOWS FALLING INTO THE UPPER SINGLE DIGITS IN THE FAR NORTH...TO THE
LOWER 20S IN THE SOUTH.
SUNDAY...A SMALL CHANCE OF SNOW WILL LINGER FROM WAUTOMA TO
MANITOWOC EARLY IN THE MORNING...BUT ANY SNOW SHOULD BE DEPARTING
QUICKLY AS THE CLIPPER MOVES TOWARDS THE OHIO VALLEY. MEANWHILE
ARCTIC HIGH PRESSURE WILL BE BUILDING SOUTHEAST OVER LAKE SUPERIOR.
THIS ARCTIC HIGH WILL BRING A VERY DRY AIRMASS INTO THE NORTHERN
PART OF THE STATE (DEWPOINTS OVER ONTARIO ARE BELOW 0F). EVEN
THOUGH TEMPS WILL BE UNSTABLE OVER LAKE SUPERIOR AND
MICHIGAN...EXPECT THIS DRY AIR TO ERODE THE CLOUD COVER AS LAKE
EFFECT STREAMERS BECOME RETREAT CLOSER TO THE SHORELINES. THINK ITS
POSSIBLE TO SEE SOME SUN IN THE AFTERNOON AS A RESULT. TEMPS WILL
FALL BACK INTO THE MIDDLE TEENS TO LOWER 20S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 250 PM CST SAT JAN 24 2015
WEAKENING CLIPPER SYSTEM SHOULD BRING LIGHT SNOW FOR
MONDAY THROUGH MONDAY EVENING. AN INCH OR LESS LIKELY IN MOST PLACES.
A BETTER CHANCE OF ACCUMULATING SNOW WEDNESDAY NIGHT AND THURSDAY
AS A CLIPPER SYSTEM AND ONE MOVING EAST FROM THE CENTRAL PLAINS
PHASE JUST TO OUR SOUTH. SHOULD BE ABLE TO GET A FEW INCHES DESPITE
MEAGER MOISTURE. VERY COLD AIR LOOKS LIKELY EARLY NEXT WEEK. SUBZERO
HIGH TEMPERATURES AND WIND CHILLS OF 30 BELOW POSSIBLE NEXT MONDAY
AND TUESDAY IF GFS AND ECMWF FORECASTS ARE CORRECT.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1037 PM CST SAT JAN 24 2015
COLD FRONT WL FINISH DROPPING SWD ACRS AREA OVERNIGHT. THE FRONT
WL BE FOLLOWED BY MAINLY FLURRIES...BUT A FEW SHSN POSSIBLE S OF
AUW AND NEAR MTW. FLOW ACRS LAKES MICHIGAN/SUPERIOR WL KEEP MVFR
CIGS IN PLACE FOR A WHILE...BUT INCOMING AIR MASS IS VERY DRY...SO
STILL EXPECT CLDS TO DISSIPATE TOMORROW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
813 AM CST SUN JAN 25 2015
.SHORT TERM...
329 AM CST
THROUGH TONIGHT...
HAVE FURTHERED THE DIMINISHING SNOWFALL TREND IN THE FORECAST FOR
TODAY...MAINLY NORTH OF INTERSTATE 80. ACROSS THE ENTIRE AREA THIS
LOOKS TO BE A MAINLY LOW IMPACT...NUISANCE TYPE SNOW...WITH SOME
COMMUNITIES IN THE NORTH QUITE POSSIBLY NOT SEEING ANY
ACCUMULATION. HAVE CONTINUED A SPECIAL WEATHER STATEMENT FOR AREAS
ALONG AND SOUTH OF I-80.
SATELLITE IMAGERY THIS MORNING DEPICTS THE CLOSED UPPER CIRCULATION
ACROSS WESTERN IA WITH AN AREA OF COOLING CLOUD TOPS IN ADVANCE OF
THIS MOVING INTO NORTHWEST IL. THIS IS CORRELATING WITH MAINLY LIGHT
RAIN OR RAIN/SNOW MIX IN THE SMALL WINDOW OF DEEPER MOIST
ADVECTION AHEAD OF THE LOW. SIMPLE EXTRAPOLATION OF THE CURRENT
AREA OF PRECIP IN IOWA AND THE DEVELOPING DEFORMATION ON THE
BACKSIDE CLEARLY INDICATE THE SOUTHERN CWA IS MORE SUPPORTED FOR
PRECIPITATION THAN THE NORTH. AT THE SURFACE...TEMPERATURES ARE
AROUND OR JUST ABOVE FREEZING ACROSS MUCH OF THE FORECAST AREA. A
DEVELOPING COLD FRONT IS ADVANCING SOUTHWARD INTO NORTHERN IL WITH
DEW POINTS IN THE MID TO UPPER 20S NORTH OF THIS FEATURE...ANOTHER
HINDRANCE OF APPRECIABLE PRECIPITATION IN NORTHERN AREAS OF THE
FORECAST AREA.
SHORT RANGE GUIDANCE LIKE ITS LONG RANGE COUNTERPARTS THE PAST
SEVERAL DAYS SHOW A FAIR AMOUNT OF DISCREPANCY...NAMELY ON COVERAGE
OF PRECIP TODAY AND PRECIP TYPE IN THE SOUTHERN CWA THIS
MORNING...BUT THEY LEND SUPPORT TO THE OBSERVATIONAL TRENDS. AS
THE AREA OF RAIN ASSOCIATED WITH ELEVATED ISENTROPIC ASCENT MOVES
INTO THE SOUTHERN FORECAST AREA...PROFILES SUPPORT A PERIOD OF
RAIN OR MIX INITIALLY...AND SOME LOCATIONS MIGHT HAVE AIR
TEMPERATURES RIGHT AT FREEZING. WOULD EXPECT ANY FREEZING RAIN
THREAT TO BE SHORT LIVED AS PROFILES TREND TOWARD SNOW. MESOSCALE
CONVERGENCE AND BAROCLINIC FORCING FOR INDUCED LIFT WOULD BECOME
MORE FAVORED JUST TO THE NORTHEAST OF THE CLOSED 850MB
CIRCULATION AS IT PIVOTS MORE EASTWARD. THAT IS FAVORED ACROSS
THE SOUTHERN TIER OR TWO OF COUNTIES LATER THIS MORNING INTO
EARLY AFTERNOON. PROFILES ARE MILD FOR IDEAL SNOW GROWTH...AND
MAYBE EVEN FOR SNOW AT ALL DOWN TOWARD GIBSON CITY FOR MUCH OF THE
MORNING. HAVE SNOW TOTALS AROUND ONE TO TWO INCHES FROM PERU TO
RENSSELAER AND SOUTHWARD FOR TODAY...WITH SNOW DEPARTING NEAR OR
SOON AFTER SUNDOWN.
AS FOR AREAS NORTH OF INTERSTATE 80...SHOULD SEE A GRADUAL INCREASE
IN LIGHT SNOW AREAWIDE BY MID-MORNING. DRY CORRIDOR NEAR 850MB
SEEN ON EARLY MORNING AMDAR SOUNDINGS OVER CHICAGO SHOULD LIMIT
INTENSITY OF ANY SNOW IN THE NORTHERN FORECAST AREA...AS WILL JUST
LESS FORCING. AREAS OF NORTHEAST ILLINOIS STILL LOOK TO HAVE
ONSHORE FLOW BEHIND THE COLD FRONT...BUT FORECAST INVERSION
HEIGHTS AS WELL AS ADAPTED ONES FROM THE 00Z GRB RAOB LAST
EVE...INDICATE VERY MARGINAL DEPTH OF CONVECTIVE CLOUDS. THUS NOT
EXPECTING MUCH IF ANY ENHANCEMENT TO ALREADY MINIMAL SYNOPTIC
FORCING OVER NORTHEAST IL. COULD SEE SOME DISORGANIZED LIGHT SNOW
OR FLURRIES LATE THIS AFTERNOON INTO THIS EVENING AS PROFILES OF
THE LAKE INDUCED STRATOCU COOL INTO THE ICE INITIATION LAYER...BUT
THIS SHOULD NOT BE A BIG DEAL.
AREAWIDE THE NORTHEAST WINDS WILL INCREASE TO 30 MPH AND MAYBE EVEN
A LITTLE HIGHER JUST OF THE LAKE. WITH MINIMAL SNOW NORTH NOT
EXPECTING ANY BLOWING SNOW ISSUES...AND SOUTH THE LOW SNOW-TO-
LIQUID RATIOS SHOULD SUPPRESS MUCH FOR BLOWING ISSUES...THOUGH
COULD LEAD TO MORE REDUCED VISIBILITY DURING THE TIME OF FALLING
SNOW THIS AFTERNOON.
MTF
&&
.LONG TERM...
329 AM CST
MONDAY THROUGH SATURDAY...
THE DISTURBED FLOW PATTERN WILL TURN MORE NORTHWESTERLY MONDAY AND
TUESDAY AS A MAJOR SYSTEM IS EXPECTED TO DEVELOP OFF THE NORTHEAST
COAST. GIVEN THIS POSSIBLY LEADING TO A SLOWER PATTERN...AS WELL
AS THE TREND OF TODAYS SYSTEM...IT IS QUITE CONCEIVABLE THAT THE
NEXT DISTURBANCE FOR MONDAY AFTERNOON AND NIGHT TRENDS WEST AS
WELL...WHICH THE EC HAS HAD IN ITS SOLUTION FOR THREE CONSECUTIVE
RUNS. THIS SYSTEM THOUGH IS NOT AS STRONG AS TODAYS AS IT IS MORE
OF A SHEARED AREA OF VORTICITY ALONG THE LINGERING BAROCLINIC
ZONE. FORCING FOR PRECIP LOOKS PRETTY LIGHT ONCE AGAIN MONDAY
AFTERNOON AND NIGHT BUT ENOUGH TO GO A LITTLE HIGHER ON POPS FOR
NORTHERN PARTS OF THE FORECAST AREA. RIGHT NOW GUIDANCE IS IN
DECENT AGREEMENT WITH SATURATING DEEP ENOUGH FOR PRECIP TYPE TO BE
LIGHT SNOW IF IT CAN OCCUR...BUT NEED TO KEEP AN EYE OUT FOR SOME
FREEZING DRIZZLE POTENTIAL IN THESE LIGHT ASCENT SITUATIONS.
A SLOW MODERATION LOOKS TO OCCUR TUESDAY INTO WEDNESDAY AND THIS
COULD BE VERY MINIMAL DEPENDING ON CLOUD COVER WHICH REMAINS A BIG
QUESTION MARK. HAVE LEANED MORE CLOUDY TUESDAY BUT STILL THINK
WITH A WESTERLY PUSH WEDNESDAY WOULD HAVE SUN POTENTIAL. LONG
RANGE GUIDANCE INDICATES A PACIFIC SYSTEM TO BE THE NEXT ONE TO
POSSIBLY BRING PRECIPITATION TO THE AREA WEDNESDAY NIGHT INTO
THURSDAY. CONTINUE POPS DURING THIS TIME FRAME AND AT THIS POINT
PROFILES ARE NEAR THE BORDER FOR RAIN OR SNOW...SO DID NOT GET TOO
FANCY WITH THE FORECAST PRECIPITATION TYPE. BEHIND THIS SYSTEM IT
SEEMS FAVORED FOR TEMPERATURES TO COOL SOME DURING THE LATTER
HALF OF THE WEEK...TO SLIGHTLY BELOW NORMAL VALUES. OBVIOUSLY ANY
FRESH SNOW COVER WOULD HELP LEAN THAT MORE TOWARD BELOW NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LIGHT SNOW THROUGH THIS AFTERNOON...MIXING WITH LIGHT RAIN/SLEET
THIS MORNING WITH IFR VIS POSSIBLE.
* IFR CIGS LIFTING TO MVFR THIS AFTERNOON...THEN SCATTERING OUT
TONIGHT.
* STRONG/GUSTY NORTHEAST WINDS THRU MID EVENING. CMS
//DISCUSSION...UPDATED 14Z...
LOW PRESSURE OVER NORTHEAST MISSOURI WILL MOVE ACROSS THE OHIO
VALLEY TONIGHT. NORTHEAST WINDS WILL REMAIN STRONG AND GUSTY THRU
THIS EVENING WITH GUSTS IN THE MID/UPPER 20KT RANGE. HEAVIEST
PRECIP SHOULD REMAIN ALONG AND SOUTH OF I-80 WITH LIGHTER AMOUNTS
NORTH. MANY AREAS REPORTING LIGHT SNOW BUT STILL SOME MIXED RAIN
AT MDW AND GYY...WHICH SHOULD TRANSITION TO SNOW BY LATE MORNING.
CMS
PREVIOUS 12Z DISCUSSION...
WEAK COLD FRONTAL BOUNDARY HAS SAGGED INTO NORTHEAST ILLINOIS
EARLY THIS MORNING...WITH IFR/LIFR CIGS NOTED IN THE VICINITY OF
THE FRONTAL BOUNDARY. EXPECT THE LIFR CIGS TO BE SOMEWHAT SHORT-
LIVED HOWEVER...AS WINDS RAMP UP FROM THE NORTHEAST.
RADAR CLEARLY SHOWS CIRCULATION WITH ALBERTA CLIPPER DROPPING
SOUTHEAST ACROSS IA...WITH EXPANSION OF WEAK RETURNS OVER NORTHERN
ILLINOIS AND A FEW REPORTS OF LIGHT SNOW BEGINNING TO REACH THE
GROUND. HIGH-RES HRRR HAS BEEN FAIRLY CONSISTENT IN BRINING NORTH
EDGE OF MORE ORGANIZED SNOW BAND ACROSS THE TERMINALS THIS MORNING
INTO MIDDAY/EARLY AFTERNOON...AND IS EXPECTED TO PRODUCE A PERIOD
OF LIGHT ACCUMULATING SNOW WITH OCCASIONAL IFR VSBYS. SNOW SHOULD
TAPER OFF TO LIGHT SNOW SHOWERS/FLURRIES THIS AFTERNOON WITH CIGS
RISING TO MVFR.
AS INDICATED ABOVE...STRONG/GUSTY NORTHEAST WINDS ARE ALREADY
RAMPING UP EARLY THIS MORNING WITH GUSTS 20-30 KT ALREAD ACROSS
FAR NORTHERN IL. 040-060 DEG WINDS NEAR 20 KT WITH GUSTS NEAR 30
KT ARE EXPECTED TO CONTIUNE INTO THE AFTERNOON BEFORE SLOW DECLINE
IN WIND SPEEDS AND A GRADUAL BACKING TO THE NORTH OCCURS. WINDS
WILL DIMINISH MORE QUICKLY TONIGHT...AS A WEAK HIGH PRESSURE RIDGE
BUILDS IN FROM THE NORTHWEST. THIS SHOULD ALLOW LOWER CLOUDS TO
SCATTER OUT OVERNIGHT.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH FOR LIGHT SNOW...MEDIUM FOR INTENSITY AND MIXED PRECIP.
* HIGH FOR CIGS THRU THIS AFTERNOON...THEN MEDIUM FOR THE REST OF
THE PERIOD.
* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...CHANCE LIGHT SNOW/MVFR.
TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MAINLY VFR DURING THE DAY THEN CHANCE OF -RASN AND
MVFR/IFR AT NIGHT.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF MVFR CIGS.
SATURDAY...CHANCE OF LIGHT SNOW/MVFR.
RATZER
&&
.MARINE...
137 AM CST
MAIN MARINE FORECAST FOCUS CONTINUES TO BE A PERIOD OF STRONG
NORTHEAST WINDS ACROSS THE SOUTHERN 2/3 OR SO OF LAKE MICHIGAN
THROUGH THIS EVENING.
A COLD FRONT HAS PUSHED SOUTH ACROSS MUCH OF LAKE MICHIGAN SINCE
SATURDAY MORNING...WITH COLD HIGH PRESSURE SPREADING ACROSS
MANITOBA...WESTERN ONTARIO AND THE NORTHERN LAKES. EARLY THIS
MORNING AN AREA OF LOW PRESSURE WAS OVER IOWA...AND THIS LOW WILL
MOVE QUICKLY SOUTHEAST TO THE LOWER OHIO VALLEY BY THIS EVENING.
THIS LOW AND THE HIGH PRESSURE TO THE NORTH OF THE LAKES WILL
COMBINE TO RAPIDLY TIGHTEN THE SURFACE PRESSURE GRADIENT ACROSS THE
LAKE THIS MORNING...WITH NORTH-NORTHEAST WINDS INCREASING TO 25-30
KT. RECENT OBSERVATION PLATFORMS ALONG THE WEST SHORE OF THE LAKE
HAVE BEEN GUSTING 26-27 KTS BEHIND THE COLD FRONT AS FAR SOUTH AS
MILWAUKEE. THESE STRONGER WINDS WILL CONTINUE TO DEVELOP SOUTHWARD
DOWN THE REMAINDER OF THE LAKE THIS MORNING. FORECAST SOUNDINGS
INDICATE WINDS TO 30 KT WILL BE PREVALENT THROUGH THE DAY...WITH A
FEW GALE FORCE GUSTS TO 35 KT POSSIBLE. WINDS WILL REMAIN GUSTY INTO
THE EVENING HOURS ACROSS THE FAR SOUTHERN PORTION OF THE LAKE...BUT
WILL DIMINISH RAPIDLY FROM THE NORTH AS A WEAK RIDGE OF HIGH
PRESSURE SPREADS IN BEHIND THE QUICK MOVING LOW WHICH MOVE TO THE
CAROLINA COAST BY MONDAY MORNING.
THE WEAK RIDGE WILL MOVE QUICKLY SOUTHEAST OF THE LAKE MONDAY...
WITH WINDS BRIEFLY BECOMING SOUTHERLY AND INCREASING BACK AROUND 20
KT OR SO AHEAD OF ANOTHER LOW PRESSURE SYSTEM WHICH WILL DROP
SOUTHEAST ACROSS THE LAKE MONDAY NIGHT...WHILE FILLING. WEAK
GRADIENT CONDITIONS WILL THEN LINGER ACROSS THE LAKE TUESDAY AND
TUESDAY NIGHT AS THE TROUGH FILLS AND A WEAK RIDGE MOVES ACROSS THE
REGION. INDICATIONS ARE THAT ANOTHER LOW WILL DEVELOP ACROSS THE
PLAINS MID-WEEK...AND WILL APPROACH THE LAKE FROM THE WEST LATE
WEDNESDAY. THIS MAY RESULT IN A BRIEF PERIOD OF ENHANCED
EAST-SOUTHEAST WINDS LATE WEDNESDAY OR WEDNESDAY NIGHT...WITH A
PERIOD OF GUSTY NORTHERLY WINDS POSSIBLE THURSDAY AS THE LOW MOVES
EAST OF THE LAKE.
FOR THE IL/NORTHWEST INDIANA NEARSHORE AREA...SMALL CRAFT ADVISORY
IS IN EFFECT FROM 6 AM CST THIS MORNING AS WINDS/WAVES QUICKLY
INCREASE AND BUILD. ADVISORY HEADLINE WILL REMAIN IN EFFECT THROUGH
MID-MORNING MONDAY...AS WAVES SLOWLY SUBSIDE BELOW 4 FT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 AM MONDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
549 AM CST SUN JAN 25 2015
.SHORT TERM...
329 AM CST
THROUGH TONIGHT...
HAVE FURTHERED THE DIMINISHING SNOWFALL TREND IN THE FORECAST FOR
TODAY...MAINLY NORTH OF INTERSTATE 80. ACROSS THE ENTIRE AREA THIS
LOOKS TO BE A MAINLY LOW IMPACT...NUISANCE TYPE SNOW...WITH SOME
COMMUNITIES IN THE NORTH QUITE POSSIBLY NOT SEEING ANY
ACCUMULATION. HAVE CONTINUED A SPECIAL WEATHER STATEMENT FOR AREAS
ALONG AND SOUTH OF I-80.
SATELLITE IMAGERY THIS MORNING DEPICTS THE CLOSED UPPER CIRCULATION
ACROSS WESTERN IA WITH AN AREA OF COOLING CLOUD TOPS IN ADVANCE OF
THIS MOVING INTO NORTHWEST IL. THIS IS CORRELATING WITH MAINLY LIGHT
RAIN OR RAIN/SNOW MIX IN THE SMALL WINDOW OF DEEPER MOIST
ADVECTION AHEAD OF THE LOW. SIMPLE EXTRAPOLATION OF THE CURRENT
AREA OF PRECIP IN IOWA AND THE DEVELOPING DEFORMATION ON THE
BACKSIDE CLEARLY INDICATE THE SOUTHERN CWA IS MORE SUPPORTED FOR
PRECIPITATION THAN THE NORTH. AT THE SURFACE...TEMPERATURES ARE
AROUND OR JUST ABOVE FREEZING ACROSS MUCH OF THE FORECAST AREA. A
DEVELOPING COLD FRONT IS ADVANCING SOUTHWARD INTO NORTHERN IL WITH
DEW POINTS IN THE MID TO UPPER 20S NORTH OF THIS FEATURE...ANOTHER
HINDRANCE OF APPRECIABLE PRECIPITATION IN NORTHERN AREAS OF THE
FORECAST AREA.
SHORT RANGE GUIDANCE LIKE ITS LONG RANGE COUNTERPARTS THE PAST
SEVERAL DAYS SHOW A FAIR AMOUNT OF DISCREPANCY...NAMELY ON COVERAGE
OF PRECIP TODAY AND PRECIP TYPE IN THE SOUTHERN CWA THIS
MORNING...BUT THEY LEND SUPPORT TO THE OBSERVATIONAL TRENDS. AS
THE AREA OF RAIN ASSOCIATED WITH ELEVATED ISENTROPIC ASCENT MOVES
INTO THE SOUTHERN FORECAST AREA...PROFILES SUPPORT A PERIOD OF
RAIN OR MIX INITIALLY...AND SOME LOCATIONS MIGHT HAVE AIR
TEMPERATURES RIGHT AT FREEZING. WOULD EXPECT ANY FREEZING RAIN
THREAT TO BE SHORT LIVED AS PROFILES TREND TOWARD SNOW. MESOSCALE
CONVERGENCE AND BAROCLINIC FORCING FOR INDUCED LIFT WOULD BECOME
MORE FAVORED JUST TO THE NORTHEAST OF THE CLOSED 850MB
CIRCULATION AS IT PIVOTS MORE EASTWARD. THAT IS FAVORED ACROSS
THE SOUTHERN TIER OR TWO OF COUNTIES LATER THIS MORNING INTO
EARLY AFTERNOON. PROFILES ARE MILD FOR IDEAL SNOW GROWTH...AND
MAYBE EVEN FOR SNOW AT ALL DOWN TOWARD GIBSON CITY FOR MUCH OF THE
MORNING. HAVE SNOW TOTALS AROUND ONE TO TWO INCHES FROM PERU TO
RENSSELAER AND SOUTHWARD FOR TODAY...WITH SNOW DEPARTING NEAR OR
SOON AFTER SUNDOWN.
AS FOR AREAS NORTH OF INTERSTATE 80...SHOULD SEE A GRADUAL INCREASE
IN LIGHT SNOW AREAWIDE BY MID-MORNING. DRY CORRIDOR NEAR 850MB
SEEN ON EARLY MORNING AMDAR SOUNDINGS OVER CHICAGO SHOULD LIMIT
INTENSITY OF ANY SNOW IN THE NORTHERN FORECAST AREA...AS WILL JUST
LESS FORCING. AREAS OF NORTHEAST ILLINOIS STILL LOOK TO HAVE
ONSHORE FLOW BEHIND THE COLD FRONT...BUT FORECAST INVERSION
HEIGHTS AS WELL AS ADAPTED ONES FROM THE 00Z GRB RAOB LAST
EVE...INDICATE VERY MARGINAL DEPTH OF CONVECTIVE CLOUDS. THUS NOT
EXPECTING MUCH IF ANY ENHANCEMENT TO ALREADY MINIMAL SYNOPTIC
FORCING OVER NORTHEAST IL. COULD SEE SOME DISORGANIZED LIGHT SNOW
OR FLURRIES LATE THIS AFTERNOON INTO THIS EVENING AS PROFILES OF
THE LAKE INDUCED STRATOCU COOL INTO THE ICE INITIATION LAYER...BUT
THIS SHOULD NOT BE A BIG DEAL.
AREAWIDE THE NORTHEAST WINDS WILL INCREASE TO 30 MPH AND MAYBE EVEN
A LITTLE HIGHER JUST OF THE LAKE. WITH MINIMAL SNOW NORTH NOT
EXPECTING ANY BLOWING SNOW ISSUES...AND SOUTH THE LOW SNOW-TO-
LIQUID RATIOS SHOULD SUPPRESS MUCH FOR BLOWING ISSUES...THOUGH
COULD LEAD TO MORE REDUCED VISIBILITY DURING THE TIME OF FALLING
SNOW THIS AFTERNOON.
MTF
&&
.LONG TERM...
329 AM CST
MONDAY THROUGH SATURDAY...
THE DISTURBED FLOW PATTERN WILL TURN MORE NORTHWESTERLY MONDAY AND
TUESDAY AS A MAJOR SYSTEM IS EXPECTED TO DEVELOP OFF THE NORTHEAST
COAST. GIVEN THIS POSSIBLY LEADING TO A SLOWER PATTERN...AS WELL
AS THE TREND OF TODAYS SYSTEM...IT IS QUITE CONCEIVABLE THAT THE
NEXT DISTURBANCE FOR MONDAY AFTERNOON AND NIGHT TRENDS WEST AS
WELL...WHICH THE EC HAS HAD IN ITS SOLUTION FOR THREE CONSECUTIVE
RUNS. THIS SYSTEM THOUGH IS NOT AS STRONG AS TODAYS AS IT IS MORE
OF A SHEARED AREA OF VORTICITY ALONG THE LINGERING BAROCLINIC
ZONE. FORCING FOR PRECIP LOOKS PRETTY LIGHT ONCE AGAIN MONDAY
AFTERNOON AND NIGHT BUT ENOUGH TO GO A LITTLE HIGHER ON POPS FOR
NORTHERN PARTS OF THE FORECAST AREA. RIGHT NOW GUIDANCE IS IN
DECENT AGREEMENT WITH SATURATING DEEP ENOUGH FOR PRECIP TYPE TO BE
LIGHT SNOW IF IT CAN OCCUR...BUT NEED TO KEEP AN EYE OUT FOR SOME
FREEZING DRIZZLE POTENTIAL IN THESE LIGHT ASCENT SITUATIONS.
A SLOW MODERATION LOOKS TO OCCUR TUESDAY INTO WEDNESDAY AND THIS
COULD BE VERY MINIMAL DEPENDING ON CLOUD COVER WHICH REMAINS A BIG
QUESTION MARK. HAVE LEANED MORE CLOUDY TUESDAY BUT STILL THINK
WITH A WESTERLY PUSH WEDNESDAY WOULD HAVE SUN POTENTIAL. LONG
RANGE GUIDANCE INDICATES A PACIFIC SYSTEM TO BE THE NEXT ONE TO
POSSIBLY BRING PRECIPITATION TO THE AREA WEDNESDAY NIGHT INTO
THURSDAY. CONTINUE POPS DURING THIS TIME FRAME AND AT THIS POINT
PROFILES ARE NEAR THE BORDER FOR RAIN OR SNOW...SO DID NOT GET TOO
FANCY WITH THE FORECAST PRECIPITATION TYPE. BEHIND THIS SYSTEM IT
SEEMS FAVORED FOR TEMPERATURES TO COOL SOME DURING THE LATTER
HALF OF THE WEEK...TO SLIGHTLY BELOW NORMAL VALUES. OBVIOUSLY ANY
FRESH SNOW COVER WOULD HELP LEAN THAT MORE TOWARD BELOW NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* IFR CIGS EARLY WITH LIGHT SNOW DEVELOPING THIS MORNING. CIGS MAY
ACTUALLY COME UP A BIT WITH THE SNOW...THOUGH VSBYS MVFR/OCNL
IFR ARE PROBABLE WITH SOME LIGHT ACCUMULATION. SNOW EXPECTED TO
TAPER OFF TO LIGHT SHSN/FLURRIES BY EARLY AFTERNOON.
* MVFR CIGS EXPECTED THIS AFTERNOON AND THIS EVENING.
* STRONG GUSTY NORTHEAST WINDS AROUND 30 KT AT TIMES. WINDS SLOWLY
DIMINISH THROUGH THIS EVENING.
RATZER
//DISCUSSION...UPDATED 12Z...
WEAK COLD FRONTAL BOUNDARY HAS SAGGED INTO NORTHEAST ILLINOIS
EARLY THIS MORNING...WITH IFR/LIFR CIGS NOTED IN THE VICINITY OF
THE FRONTAL BOUNDARY. EXPECT THE LIFR CIGS TO BE SOMEWHAT SHORT-
LIVED HOWEVER...AS WINDS RAMP UP FROM THE NORTHEAST.
RADAR CLEARLY SHOWS CIRCULATION WITH ALBERTA CLIPPER DROPPING
SOUTHEAST ACROSS IA...WITH EXPANSION OF WEAK RETURNS OVER NORTHERN
ILLINOIS AND A FEW REPORTS OF LIGHT SNOW BEGINNING TO REACH THE
GROUND. HIGH-RES HRRR HAS BEEN FAIRLY CONSISTENT IN BRINING NORTH
EDGE OF MORE ORGANIZED SNOW BAND ACROSS THE TERMINALS THIS MORNING
INTO MIDDAY/EARLY AFTERNOON...AND IS EXPECTED TO PRODUCE A PERIOD
OF LIGHT ACCUMULATING SNOW WITH OCCASIONAL IFR VSBYS. SNOW SHOULD
TAPER OFF TO LIGHT SNOW SHOWERS/FLURRIES THIS AFTERNOON WITH CIGS
RISING TO MVFR.
AS INDICATED ABOVE...STRONG/GUSTY NORTHEAST WINDS ARE ALREADY
RAMPING UP EARLY THIS MORNING WITH GUSTS 20-30 KT ALREAD ACROSS
FAR NORTHERN IL. 040-060 DEG WINDS NEAR 20 KT WITH GUSTS NEAR 30
KT ARE EXPECTED TO CONTIUNE INTO THE AFTERNOON BEFORE SLOW DECLINE
IN WIND SPEEDS AND A GRADUAL BACKING TO THE NORTH OCCURS. WINDS
WILL DIMINISH MORE QUICKLY TONIGHT...AS A WEAK HIGH PRESSURE RIDGE
BUILDS IN FROM THE NORTHWEST. THIS SHOULD ALLOW LOWER CLOUDS TO
SCATTER OUT OVERNIGHT.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH IN WIND TRENDS.
* MEDIUM-HIGH IN SNOW TIMING...MEDIUM IN DETAILS OF CIG/VSBY
THROUGH MID-DAY.
* MEDIUM-LOW IN TIMING OF SCATTERING MVFR CIGS TONIGHT.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...CHANCE LIGHT SNOW/MVFR.
TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MAINLY VFR DURING THE DAY THEN CHANCE OF -RASN AND
MVFR/IFR AT NIGHT.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF MVFR CIGS.
SATURDAY...CHANCE OF LIGHT SNOW/MVFR.
RATZER
&&
.MARINE...
137 AM CST
MAIN MARINE FORECAST FOCUS CONTINUES TO BE A PERIOD OF STRONG
NORTHEAST WINDS ACROSS THE SOUTHERN 2/3 OR SO OF LAKE MICHIGAN
THROUGH THIS EVENING.
A COLD FRONT HAS PUSHED SOUTH ACROSS MUCH OF LAKE MICHIGAN SINCE
SATURDAY MORNING...WITH COLD HIGH PRESSURE SPREADING ACROSS
MANITOBA...WESTERN ONTARIO AND THE NORTHERN LAKES. EARLY THIS
MORNING AN AREA OF LOW PRESSURE WAS OVER IOWA...AND THIS LOW WILL
MOVE QUICKLY SOUTHEAST TO THE LOWER OHIO VALLEY BY THIS EVENING.
THIS LOW AND THE HIGH PRESSURE TO THE NORTH OF THE LAKES WILL
COMBINE TO RAPIDLY TIGHTEN THE SURFACE PRESSURE GRADIENT ACROSS THE
LAKE THIS MORNING...WITH NORTH-NORTHEAST WINDS INCREASING TO 25-30
KT. RECENT OBSERVATION PLATFORMS ALONG THE WEST SHORE OF THE LAKE
HAVE BEEN GUSTING 26-27 KTS BEHIND THE COLD FRONT AS FAR SOUTH AS
MILWAUKEE. THESE STRONGER WINDS WILL CONTINUE TO DEVELOP SOUTHWARD
DOWN THE REMAINDER OF THE LAKE THIS MORNING. FORECAST SOUNDINGS
INDICATE WINDS TO 30 KT WILL BE PREVALENT THROUGH THE DAY...WITH A
FEW GALE FORCE GUSTS TO 35 KT POSSIBLE. WINDS WILL REMAIN GUSTY INTO
THE EVENING HOURS ACROSS THE FAR SOUTHERN PORTION OF THE LAKE...BUT
WILL DIMINISH RAPIDLY FROM THE NORTH AS A WEAK RIDGE OF HIGH
PRESSURE SPREADS IN BEHIND THE QUICK MOVING LOW WHICH MOVE TO THE
CAROLINA COAST BY MONDAY MORNING.
THE WEAK RIDGE WILL MOVE QUICKLY SOUTHEAST OF THE LAKE MONDAY...
WITH WINDS BRIEFLY BECOMING SOUTHERLY AND INCREASING BACK AROUND 20
KT OR SO AHEAD OF ANOTHER LOW PRESSURE SYSTEM WHICH WILL DROP
SOUTHEAST ACROSS THE LAKE MONDAY NIGHT...WHILE FILLING. WEAK
GRADIENT CONDITIONS WILL THEN LINGER ACROSS THE LAKE TUESDAY AND
TUESDAY NIGHT AS THE TROUGH FILLS AND A WEAK RIDGE MOVES ACROSS THE
REGION. INDICATIONS ARE THAT ANOTHER LOW WILL DEVELOP ACROSS THE
PLAINS MID-WEEK...AND WILL APPROACH THE LAKE FROM THE WEST LATE
WEDNESDAY. THIS MAY RESULT IN A BRIEF PERIOD OF ENHANCED
EAST-SOUTHEAST WINDS LATE WEDNESDAY OR WEDNESDAY NIGHT...WITH A
PERIOD OF GUSTY NORTHERLY WINDS POSSIBLE THURSDAY AS THE LOW MOVES
EAST OF THE LAKE.
FOR THE IL/NORTHWEST INDIANA NEARSHORE AREA...SMALL CRAFT ADVISORY
IS IN EFFECT FROM 6 AM CST THIS MORNING AS WINDS/WAVES QUICKLY
INCREASE AND BUILD. ADVISORY HEADLINE WILL REMAIN IN EFFECT THROUGH
MID-MORNING MONDAY...AS WAVES SLOWLY SUBSIDE BELOW 4 FT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 9 AM MONDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 9 AM MONDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
636 AM EST SUN JAN 25 2015
.SYNOPSIS...
ISSUED AT 430 AM EST SUN JAN 25 2015
AN AREA OF LOW PRESSURE WILL MOVE FROM SOUTHERN IOWA THIS MORNING
TO SOUTHWEST INDIANA BY MID AFTERNOON AND THEN THROUGH KENTUCKY
TONIGHT. THIS CLIPPER SYSTEM WILL SPREAD ACCUMULATING SNOW OVER
PARTS OF NORTH CENTRAL AND NORTHERN INDIANA AND NORTHWEST OHIO
TODAY WITH RAIN SOUTH OF THIS AREA. HIGH TEMPERATURES WILL
OCCUR THIS MORNING WITH READINGS RANGING FROM THE LOWER 20S NORTH
TO UPPER 30S SOUTH. EXPECT FALLING TEMPERATURES DURING THE DAY.
LOWS TONIGHT WILL BE VERY COLD WITH SINGLE DIGITS ACROSS THE NORTH
AND TEENS SOUTH.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EST SUN JAN 25 2015
CHALLENGING SHORT TERM FORECAST AS PCPN TYPE IN QUESTION EARLY TODAY
AND SNOWFALL AMOUNTS WILL DEPEND ON TIMING OF CHANGEOVER TO ALL
SNOW. 00Z MODELS GENERALLY IN GOOD AGREEMENT SYNOPTICALLY WITH
ALMOST ALL SOLUTIONS TAKING SURFACE LOW SOUTHEAST FROM IA THIS
MORNING TO NEAR KEVV BY EARLY AFTERNOON...THEN EAST ACROSS NORTHERN
KENTUCKY TONIGHT. PRECIPITATION WILL SPREAD EAST ACROSS THE LOCAL
AREA TODAY AHEAD AND NORTH OF THE LOW.
STRONG MERIDIONAL JET DIVING SOUTH THROUGH THE PLAINS WILL DRIVE
CLIPPER SYSTEM SOUTHEAST TODAY. LOW LEVEL NORTHEAST FLOW WILL
INCREASE AND THIS WILL BRING COLDER AIR SOUTH HELPING ERODE WARM
LAYER ALOFT AND CHANGE PCPN OVER TO ALL SNOW FROM NORTH TO SOUTH.
THERE IS A BIT OF A CONCERN THOUGH AS MOST HIRES GUIDANCE HAS BEEN
ANYWHERE FROM 2 TO 5 DEGREES TOO WARM WITH SFC TEMPS EARLY THIS
MORNING ACROSS LOWER MICHIGAN. AS OF 08Z THOUGH WE ARE FINALLY
STARTING TO SEE A THERMAL RESPONSE IN SFC OBS WITH TEMPS DROPPING A
FEW DEGREES. THIS IS ENCOURAGING BUT STILL CONCERNED THAT MODELS ARE
A FEW HOURS TOO FAST BRINGING THE COLDER AIR SOUTH WHICH IN TURN
COULD DELAY CHANGEOVER IN FAR SOUTH UNTIL MID AFTERNOON.
HRRR...RUC AND LAMP GUIDANCE HAVE BEEN PLAYING CATCHUP ALL NIGHT.
HAVE MANUALLY ADJUSTED HOURLY SFC TEMPS WITH SLIGHTLY SLOWER COOLING
THAN RUC GUIDANCE SUGGESTS. DO EXPECT COLDER AIR TO QUICKLY MOVE SOUTH
ONCE CLIPPER GETS CLOSER AND PRESSURE GRADIENT TIGHTENS LATER THIS
MORNING.
MEANWHILE...LACK OF LOW CLOUDS ALONG WITH LIGHT WINDS IN THE WESTERN
CWA HAS ALLOWED SFC TEMPS THERE TO DROP TO AROUND FREEZING WITH SOME
FOG DEVELOPMENT. DO EXPECT TEMPS HERE TO RISE ABOVE FREEZING AHEAD
OF PCPN ARRIVAL WITH SFC TEMPS ACROSS CENTRAL ILLINOIS IN THE MID TO
UPPER 30S EARLY THIS MORNING. THIS COMBINED WITH 1000-850MB WARM
TONGUE OF 2 TO 4C DEPICTED BY HIRES GUIDANCE SUGGEST A MIX OF RAIN
AND SNOW UNTIL WARM LAYER IS FULLY ERODED. TOP DOWN METHOD ACTUALLY
DEPICTS A FEW HOURS OF JUST RAIN ACROSS THE EXTREME SOUTHERN CWA
LATE MORNING INTO EARLY AFTERNOON BEFORE FULLY CHANGING OVER TO
SNOW.
THE FARTHER SOUTH TRACK OF CLIPPER HAS ALSO MEANT A SOUTHWARD SHIFT
IN STRONGEST FORCING AND HEAVIEST PCPN AXIS. STRONGEST FGEN FORCING
AND BANDING POTENTIAL NOW LOOKS TO BE JUST SOUTH OF OUR AREA. THIS
COMBINED WITH MIXED PCPN AND DELAYED CHANGEOVER TO SNOW HAS LED TO
DECREASED SNOW AMOUNTS OVER THE ENTIRE AREA. MODEL QPF NOW GENERALLY
AROUND A QUARTER INCH SOUTH OF THE US24 CORRIDOR. MIXING RATIOS OF 3
TO 4 G/KG AND PWATS AROUND 0.5 INCHES STILL A CONCERN...ESPECIALLY
IF ANY BANDING DEVELOPS. STILL EXPECT A SWATH OF 2 TO 4 INCHES
ACROSS THE FAR SOUTH AND THE HIGHER END AMOUNTS SOUTHEAST WHERE
PIVOT POINT AND SNOW THIS EVENING TAKE ADVANTAGE OF SLIGHTLY BETTER
RATIOS. ISOLATED AMOUNTS OF 5 INCHES NOT OUT OF QUESTION IF BANDING
CLIPS THIS AREA. WITH THIS BEING MID WINTER AND EXPECTATION OF A WET
2 TO 4 INCHES WITH LOW IMPACTS FOR TRAVEL HAVE OPTED TO NOT ISSUE
ANY ADVISORY AT THIS TIME. WILL HIGHLIGHT SNOWFALL IN AN SPS AND
HWO.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 439 AM EST SUN JAN 25 2015
NEXT CLIPPER-TYPE SYSTEM TO POTENTIALLY IMPACT THE AREA WILL ARRIVE
ON MONDAY NIGHT. FORCING MECHANISM IS REALLY MORE ACCURATELY
DESCRIBED AS JUST A THIN RIBBON OF CYCLONIC SHEAR VORTICITY ON THE
UPWIND SIDE OF DEEPENING EAST COAST TROUGH. AS SUCH...FORCING FOR
ASCENT IS PRETTY MINUSCULE AND RESIDENT AIRMASS...AT LEAST IN THE
MIDLEVELS...IS VERY DRY. WEAK 285K ISENTROPIC ASCENT AND SUBTLE LOW
LEVEL MOISTURE ADVECTION MAY GENERATE SOME VERY LIGHT SNOW BUT
LITTLE TO NO ACCUMULATION IS EXPECTED. PREFERENCE STILL LIES WITH
THE DRIER/FURTHER SOUTHWEST CANADIAN AND EUROPEAN SOLUTIONS.
ACTUALLY AM A LITTLE CONCERNED ABOUT POTENTIAL FOR FREEZING DRIZZLE.
NAM AND GFS FORECAST SOUNDINGS INDICATE DEEP ENOUGH SATURATION TO
SUPPORT ICE NUCLEATION BUT JUST BARELY AND AM CONCERNED THEY ARE
OVERDOING THE EXTENT OF LOW LEVEL MOISTURE AND ASCENT. WILL HOLD OFF
ON INCLUDING IN THE FORECAST FOR NOW GIVEN THE HIGHER PROBABILITY
THAT ANY PRECIPITATION THAT DOES MANAGE TO OCCUR WILL DO SO IN AN
ENVIRONMENT ADEQUATELY SATURATED TO SUPPORT ICE NUCLEI AND OTHER
LOCATIONS WILL SIMPLY REMAIN DRY. SOMETHING TO KEEP AN EYE ON THOUGH.
MORE IMPRESSIVE WAVE IS SET TO PLOW OVER THE WEST COAST RIDGE ON
WEDNESDAY. THIS ACTUALLY FORCES DOWNSTREAM HEIGHT RISES LOCALLY WITH
A BRIEF RETURN TO SOUTHWEST FLOW AND WARMER TEMPERATURES. SHORTWAVE
WILL THEN ENTER OUR REGION ON THURSDAY WITH THE NEXT DECENT CHANCE
OF PRECIP. NEEDLESS TO SAY....FORECAST CONFIDENCE IN EXACT TRACK IS
LOW AND THIS WILL HAVE A LARGE IMPACT ON THERMAL PROFILES AND QPF
TOTALS. CURRENTLY APPEARS THE BEST CHANCE FOR SIGNIFICANT SNOW WILL
REMAIN OVER CENTRAL MICHIGAN WITH MORE OF A MIX ACROSS NORTHERN
INDIANA AND OHIO. THIS WILL UNDOUBTEDLY CHANGE AS WE GET CLOSER
THOUGH.
AFTER A COLD START ON MONDAY...TEMPERATURES WILL QUICKLY RETURN TO
VALUES AT OR ABOVE NORMAL FOR THE MIDWEEK PERIOD. COOLER TEMPS
EXPECTED AFTER THURSDAY`S WAVE BUT MUCH COLDER CONDITIONS STILL
APPEAR POSSIBLE EARLY NEXT WEEK AFTER A THIRD WAVE/ARCTIC FRONT
PASSES OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 632 AM EST SUN JAN 25 2015
NOT MUCH CHANGE IN THINKING FOR LATEST TAF PACKAGE. MVFR AND IFR
CONDITIONS WERE DEVELOPING ACROSS THE REGION AND EXPECT TERMINALS
TO DROP THROUGH THE MORNING. LIGHT SNOW WILL SPREAD ACROSS TAF
SITES MID TO LATE MORNING. KSBN REMAINS ON NORTHERN FRINGE OF PCPN
SHIELD WHILE KFWA DEEPER INTO PCPN. COULD BE A BRIEF PERIOD OF
RAIN OR SLEET TO MIX WITH SNOW AT KFWA BUT EXPECT TO BE SHORT
DURATION IF AT ALL. NORTHEAST WINDS WILL INCREASE TODAY WITH 10 TO 20
KNOTS EXPECTED. PCPN TO DIMINISH LATE AFTERNOON AT KSBN AND EARLY
EVENING AT KFWA WITH PARTIAL CLEARING POSSIBLE OVERNIGHT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
552 AM CST SUN JAN 25 2015
...UPDATED FOR AVIATION DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CST SUN JAN 25 2015
A 500 MILLIBAR SHORTWAVE TROUGH WAS MOVING SOUTHEAST OVER THE
CENTRAL PLAINS EARLY THIS MORNING. AT THE SURFACE, AN ASSOCIATED LOW
PRESSURE SYSTEM WAS ALSO TRACKING SOUTHEAST OVER SOUTHERN IOWA. THE
UPPER WAVE WAS MOVING INTO OKLAHOMA EARLY THIS MORNING AS LIGHT
PRECIPITATION THAT WAS OVER THE AREA EARLIER IN THE NIGHT HAD MOVED
INTO EASTERN OKLAHOMA AND CLOUDS WERE DIMINISHING OVER WESTERN
KANSAS.
FAIRLY STRONG WINDS ALOFT WERE ALSO MOVING SOUTHEAST OVER THE AREA
IN THE WAKE OF THE SHORTWAVE. THE KDDC VWP WAS SHOWING 50-55 KNOT
WINDS OFF THE SURFACE WHICH IS IN GOOD AGREEMENT WITH 850 MILLIBAR
WIND PROGS FROM THE RUC13 AND HRRR. THESE MODELS SHOW A BROAD AREA
OF 50-60 KNOT WINDS OVER SOUTHWEST KANSAS EARLY THIS MORNING WHICH
MAKES SENSE GIVEN THE NUMEROUS REPORTS OF 25-30 KNOT WINDS REPORTS
FROM AREA AWOS`S. THE MODELS SHOW THE AREA OF STRONGER WINDS GRADUALLY
PROPAGATING SOUTHWARD INTO OKLAHOMA BY MID/LATE MORNING. WE SHOULD
SEE THE STRONG WINDS CONTINUING THROUGH MUCH OF THE DAY. THERE COULD
BE A SMALL WINDOW OF OPPORTUNITY FOR 50+ KNOT WIND GUSTS AROUND
MEDICINE LODGE LATER THIS MORNING BUT THE STRONGEST WINDS SHOULD
BE SOUTH OF SOUTHWEST KANSAS BY THE TIME THE BOUNDARY LAYER BEGINS
TO MIX OUT. WINDS IN THE LOWER ATMOSPHERE WILL GRADUALLY WEAKEN DURING
THE AFTERNOON HOURS. WE SHOULD SEE WINDS DROP OFF FAIRLY QUICKLY TOWARD
SUNSET AS THE BOUNDARY LAYER DECOUPLES.
THE MODELS ARE SHOWING A COOLER DAY FOR SOUTHWEST KANSAS THAN WAS
PREVIOUSLY THOUGHT. 850 MILLIBAR TEMPERATURES THIS AFTERNOON WILL BE
COOLER THAN SATURDAY BY SOME 4-8 DEGREES CELSIUS. THIS WILL TRANSLATE
TO HIGHS RANGING FROM AROUND 50 AT HAYS TO THE MID/UPPER 50S FROM
DODGE CITY WEST TO THE COLORADO LINE. SURFACE WINDS TONIGHT WILL
GRADUALLY SWITCH TO THE WEST AND COULD INCREASE AGAIN TO AROUND
10-12 KNOTS. THIS COULD KEEP LOW TEMPERATURES HELD UP IN THE LOWER
TO MIDDLE 30S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 308 AM CST SUN JAN 25 2015
UPPER LEVEL RIDGING WILL PERSIST OVER THE ROCKIES MONDAY AND
TUESDAY BEFORE A SHORTWAVE TROUGH FLATTENS OUT THE RIDGE ON
WEDNESDAY AND PROGRESSES ACROSS THE PLAINS. THIS ENTIRE PERIOD
WILL BE CHARACTERIZED BY WARM TEMPERATURES WITH VARYING WIND
DIRECTIONS FROM DAY TO DAY IN RESPONSE TO SUBTLE CHANGES IN THE
SURFACE PRESSURE FIELD. HIGHS OUGHT TO REACH INTO THE UPPER 60S TO
LOWER 70S. A COLD FRONT WILL PASS ACROSS WESTERN KANSAS WEDNESDAY
AFTERNOON IN THE WAKE OF THIS SHORTWAVE TROUGH, WITH COOLER
TEMPERATURES RETURNING FOR WEDNESDAY NIGHT THROUGH THE REMAINDER
OF THE WEEK AS SURFACE HIGH PRESSURE BUILDS IN.
THERE IS A LOT OF UNCERTAINTY IN THE FORECAST AFTER FRIDAY AS THE
VARIOUS MODELS ARE EXHIBITING LOTS OF VARIABILITY WITH RESPECT TO
THE AMPLITUDE OF AN UPPER LEVEL LOW OVER BAJA. COLD AIR CONTINUES
TO BE DELIVERED INTO THE MIDWEST AND GREAT LAKES REGIONS. IF THE
SOUTHWESTERN SYSTEM PROGRESSES FAR ENOUGH EAST AND INTERACTS WITH
THE WESTERN AND SOUTHERN EDGE OF THE COLD DOME, THEN SNOW WOULD BE
POSSIBLE. THE OVERALL TREND IN THE MODELS OVER THE PAST FEW RUNS
HAS BEEN FOR A STRONGER SYSTEM OVER THE DESERT SOUTHWEST AND BAJA.
BUT IT IS VERY UNCERTAIN JUST HOW FAR NORTHEAST ANY PRECIPITATION
WOULD OCCUR AND JUST HOW COLD IT WILL BE OVER WESTERN KANSAS. FOR
NOW, THERE IS FAIRLY HIGH CONFIDENCE IN A CHANGE TO COOLER OR COLDER
TEMPERATURES FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 548 AM CST SUN JAN 25 2015
EXPECT NORTH-NORTHWEST WINDS TO INCREASE TO 25KTS BY 17Z AND
PERSIST THROUGH 22Z AS WEAK SURFACE HIGH PRESSURE BUILDS INTO
WESTERN KANSAS. WINDS WILL DROP OFF QUICKLY BY 00Z. VFR CONDITIONS
CAN BE EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 56 34 70 35 / 0 0 0 0
GCK 57 34 71 35 / 0 0 0 0
EHA 55 37 69 35 / 0 0 0 0
LBL 57 33 69 35 / 0 0 0 0
HYS 50 31 70 36 / 0 0 0 0
P28 54 31 70 37 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...FINCH
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
628 AM EST SUN JAN 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EST SUN JAN 25 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
DOMINTING THE GREAT LKS BTWN HI AMPLITUDE RDG ALONG THE W COAST AND
A DEEP UPR TROF IN ERN NAMERICA CENTERED OVER NRN QUEBEC. SFC HI
PRES UNDER THIS NW FLOW IS BLDG SE THRU NW ONTARIO...WITH A COLD NNE
FLOW ON ITS SRN FLANK ADVECTING H85 TEMPS AS LO AS -15C OVER LK SUP
EARLY THIS MRNG. THE INFUSION OF THIS VERY COLD AIR OVER THE
RELATIVELY WARM LK SUP WATERS IS RESULTING IN SOME LK EFFECT SN
SHOWERS ACROSS MAINLY NCENTRAL UPR MI...WHERE THE LLVL FLOW IS
PRESENTING A MORE SGNFT UPSLOPE WIND COMPONENT. DESPITE FVRBL SN
GROWTH MICROPHYSICS WITH THE DGZ WITHIN MUCH OF THE CONVECTIVE
LYR...HI STABILITY/DRYNESS OF INCOMING AIRMASS PER THE 00Z YPL
RAOB...WHERE THE 00Z PWAT WAS ONLY 0.05 INCH AND THE SUBSIDENCE
INVRN WAS LOCATED NEAR H9 /MQT VWP INDICATES THE INVRN BASE HERE IS
NEAR 3K FT AGL/...AS WELL AS THE LARGER SCALE ACYC FLOW THAT IS
MINIMIZING LLVL CNVGC IS TENDING TO LIMIT THE INTENSITY OF THE LES.
OVER THE E...SKIES HAVE BEGUN TO CLEAR AT NEWBERRY WITH MINIMAL
OVERWATER TRAJECTORY AND SOME DOWNSLOPING OF THE LLVL NE FLOW OFF
ONTARIO...WHERE SFC DEWPTS EARLY THIS MRNG ARE AS LO AS -20 TO -25F
TO THE N OF LK SUP. LOOKING FARTHER UPSTREAM...A FAIRLY STRONG
SHRTWV IS MOVING THRU WRN CANADA OVER TOP THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE LES TRENDS ASSOCIATED WITH
THE COLD NE LLVL FLOW THAT WL PERSIST INTO THIS AFTN. FOCUS FOR TNGT
SHIFTS TO LO TEMPS AND SN CHCS LATE OVER THE W ASSOCIATED WITH
DISTURBANCE NOW TRACKING THRU WRN CANADA.
TODAY...SFC HI PRES CENTER IS FCST TO DRIFT SLOWLY TO THE SE OVER
FAR NE LK SUP BY 00Z MON. LLVL NE FLOW WL PERSIST THRU THIS
MRNG...BUT THEN WEAKEN AS THE HI CENTER MOVES CLOSER AND SFC RDG
AXIS EXTENDING TO THE SW MOVES OVHD BY 00Z. WITH THE -15C H85
ISOTHERM OVER CENTRAL LK SUP AND THE DGZ IN THE 1-3K FT LYR
ENCOMPASSING MUCH OF THE CONVECTIVE LYR...SOME FLUFFY LES WL PERSIST
IN THE NE SN BELTS OVER MAINLY THE NCENTRAL. DESPITE THE PRESENCE OF
THE DGZ AND SUFFICIENT CHILL OF THE AIRMASS...INVRN BASE NEAR 3K FT
AGL AND ACYC NATURE OF THE H925 FLOW WL CONTINUE TO LIMIT ADDITIONAL
SN ACCUMS TO AN INCH OR LESS. DURING THE AFTN WHEN THE WINDS/UPSLOPE
FORCING DIMINISH FURTHER AND THE SFC RDG AXIS BECOMES MORE
PRONOUNCED...THE LES SHOULD TEND TO DIMINISH EVEN FURTHER. THE ERN
CWA SHOULD BE MOSUNNY WITH DOWNSLOPE FLOW/MINIMAL OVERWATER
TRAJECTORY OF THE DRY AIRMASS. NEAR THE WI BORDER...SOME BREAKS IN
THE SC OVC ARE LIKELY BY MID/LATE AFTN WITH THE CLOSER APRCH OF THE
SFC RDG AXIS. BUT EVEN WHERE THE SUN COMES OUT...HI TEMPS WL BE HARD
PRESSED TO RISE OUT OF THE TEENS PER OBSVD HI TEMPS IN ONTARIO YDAY.
TNGT...AS THE SFC RDG AXIS SHIFTS TO THE E AND THE SHRTWV NOW OVER
WRN CANADA DIGS THRU SCENTRAL CANADA TOWARD THE UPR LKS...THE LLVL
FLOW WL TURN TO THE SSW. FCST SDNGS INDICATE ANY LINGERING LO CLDS
WL DSPT OR SHIFT OUT INTO LK SUP AND GIVE WAY TO A PERIOD OF MOCLR
CONDITIONS BEFORE CLDS ASSOCIATED WITH ISENTROPIC ASCENT AHEAD OF
THE APRCHG CLIPPER SHRTWV INVADE THE AREA NW TO SE. COMBINATION OF
EARLIER ARRIVING CLDS/STRENGTHENING SSW WIND WL TEND TO LIMIT THE
DIURNAL TEMP FALL OVER THE W. BUT OVER THE E...EXPECT TEMPS TO FALL
TOWARD THE LO END OF GUIDANCE BEFORE THE LATER ARRIVAL OF HI CLDS
AND STRENGTHENING FLOW OFF LK MI TENDS TO STOP THE TEMP FALL. THE
BULK OF THE MODELS ARE STILL HINTING THE LEADING EDGE OF THE WAA SN
WL REACH THE WRN CWA BY 12Z MON...SO RETAINED SOME CHC POPS THERE
LATE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM EST SUN JAN 25 2015
EXPECT NO SIGNIFICANT PATTERN CHANGES THROUGH THE PERIOD...AS A
500MB TROUGH LINGERS ACROSS EASTERN CANADA AND MUCH OF THE EAST HALF
OF THE U.S. THE MAIN EXCEPTION WILL BE TUESDAY THROUGH WEDNESDAY AS
THE RIDGE ACROSS THE WEST MOVES ACROSS THE PLAINS AND GREAT LAKES
REGION. BY 00Z THURSDAY 850MB TEMPS SHOULD WARM TO -4 TO -1C
/WARMEST OFF THE 24/12Z ECMWF/. SFC TEMPS TOPPING OUT NEAR FREEZING
WILL BE THE RESULT WEDNESDAY AFTERNOON. THE WARM SPELL WILL BE SHORT
LIVED AS COLDER AIR SET UP OVER N CENTRAL CANADA SHIFTS SINKS ACROSS
HUDSON BAY ON FRIDAY...AND SURGE ACROSS ONTARIO AND INTO THE UPPER
GREAT LAKES FROM SATURDAY THROUGH THE START OF THE NEXT WORK WEEK.
THE EXACT TIMING...SATURDAY OR LATER SATURDAY NIGHT...IS STILL IN
QUESTION. THE 25/00Z IS A LITTLE SLOWER TO PUSH THE COLD AIR DOWN.
GIVEN THAT THIS IS OVER 150HRS OUT...WILL GO WITH A BLENDED SOLUTION
FOR NOW.
AS FOR SOME OF THE SPECIFICS...WE WILL START 12Z MONDAY WITH THE
NEXT LOW KNOCKING ON THE DOOR /SET UP ACROSS SE MANITOBA THROUGH N
MN/. THE CANADIAN AND ECMWF ARE ON THE SW END OF THE LOW TRACK
ENVELOPE...WHILE THE NAM AND GFS ARE FARTHER TO THE NE AND TRACK IT
OVER W LAKE SUPERIR BY 00Z TUESDAY. EITHER WAY THE ROUGHLY 150 MILE
DIFFERNECE IN PLACMENT OF THE LOW DOES MAKE A DIFFERENCE IN THE WIND
FIELDS...BUT BOTH INDICATE SNOW FOR WESTERN AND AT LEAST MOST OF
CENTRAL UPPER MI. THIS SW TREND IN THE BETTER FORCING OCCURRED WITH
THE LAST SIGNIFICANT CLIPPER SYSTEM TOO...SO WE WILL SEE IF THIS
CONTINUES. WILL KEEP THE LIKELY POPS IN THE W ONLY.
BEHIND THE LOW A SFC RIDGE WILL SLIDE ACROSS UPPER MI FROM THE
W...AS THE NEXT LOW ORGANIZES ACROSS THE PLAINS STATES
TUESDAY/WEDNESAY. EXPECT THIS LOW /EXTENDING FROM ND ALL THE WAY
THROUGH N TX AT 18Z WEDNESDAY TO PUSH ACROSS FAR S LAKE MI BY
DAYBREAK THURSDAY. THERE IS AMAZING CONSISTANCY WITH THE TRACK AND
STRENGTH OF THIS LOW FOR THIS 108HR FCST. THE INVERTED TROUGH WILL
EXTEND ALL THE WAY THROUGH N LAKE SUPERIOR 00-12Z THURSDAY. THIS
WILL BE THE FOCUS FOR SNOW...ASSISTED BY THE NEXT ELONGATED
SHORTWAVE SWINGING IN FROM THE NW. AT THIS POINT THE GFS IS HINTING
IN 3-5IN OF SNOW FROM 00Z THURSDAY THROUGH 00Z FRIDAY...BEFORE THE
INVERSION HEIGHTS START DROPPING BELOW 5KFT AS STRONG HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 628 AM EST SUN JAN 25 2015
A MOIST NE FLOW TO THE S OF HI PRES IN NW ONTARIO AND UNDER LO
SUBSIDENCE INVRN WL RESULT IN MVFR CIGS AT ALL 3 TAF SITES INTO THIS
AFTN. AS THE HI PRES RDG MOVES INTO UPR MI LATER TODAY...THE LO CLDS
WL DISSIPATE AND GIVE WAY TO VFR CONDITIONS. BUT MID/HI CLDS WL
MOVE IN TNGT WITH RETURNING MSTR IN THE S FLOW AHEAD OF ANOTHER LO
PRES MOVING SEWD THRU SCENTRAL CANADA. SOME -SN/MVFR CONDITIONS IN
ADVANCE OF THIS DISTURBANCE WL ARRIVE LATE AT IWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 352 AM EST SUN JAN 25 2015
N TO NE WINDS UP TO 20-25 KTS THIS MORNING WILL DIMINISH THIS
AFTERNOON WITH ARRIVAL OF A HI PRES RIDGE. AS THE HI SHIFTS TO THE E
AND A LO PRES APPROACHES FROM THE NW TONIGHT AND MON...EXPECT
INCREASING S WINDS UP TO 25-30 KTS ON MON...STRONGEST OVER THE E
HALF OF THE LAKE. WINDS WILL THEN DIMINISH TO UNDER 20 KTS ON TUE
AND TUE NIGHT AS THE WEAKENING LO SLIDES TO THE SE AND A TRAILING HI
PRES RIDGE MOVES THRU THE UPPER LAKES. LIGHT S WINDS IN THE WAKE OF
THE DEPARTING HI ON WED WILL GIVE WAY STRENGTHENING N WINDS UP TO 25-
30 KTS ON THU FOLLOWING THE PASSAGE OF A LO PRES THRU THE LOWER
LAKES. THE ARRIVAL OF MUCH COLDER AIR AND INCREASING WAVES WILL
LIKELY RESULT IN SOME HEAVY FREEZING SPRAY BY LATE THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
400 AM MST SUN JAN 25 2015
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 1257 AM MST SUN JAN 25 2015
A WELL-DEFINED MID LEVEL SHORTWAVE CONTINUES TO DIVE QUICKLY ACROSS
THE CENTRAL PLAINS EARLY THIS MORNING. THIS SYSTEM WAS RESPONSIBLE
FOR SCATTERED RAIN AND/OR SNOW SHOWERS ACROSS MUCH OF SOUTHEAST WY
AND THE WESTERN NE PANHANDLE LAST EVENING. HOWEVER...LATEST TRENDS
IN RADAR/SAT IMAGERY INDICATE THIS ACTIVITY HAS GREATLY DIMINISHED
IN COVERAGE AS OF 08Z OWING TO INCREASING SUBSIDENCE IN THE WAKE OF
THE DEPARTING WAVE. WE ARE STILL SEEING A FEW WEAK ECHOS FROM KCYS
ALONG THE WY/NE STATE LINE NEAR SCOTTSBLUFF...BUT POTENTIAL FOR ANY
MEASURABLE PCPN IS UNLIKELY WITH DRYING LOW LEVELS AND LARGER SCALE
SINKING MOTION OVERSPREADING THE AREA. LLVL GRADIENTS STAY ELEVATED
TODAY WITH AROUND 50 METERS BETWEEN CAG-CPR AT H85. FAST NORTHWEST
FLOW ALOFT PERSISTS WITH A 130 KT H25 JET OVER EASTERN MT/WY...SO
THE WIND PRONE AREAS WILL UNDOUBTEDLY BE QUITE WINDY. A FEW WYDOT
SENSORS NEAR ARLINGTON HAVE RECORDED WINDS NEAR 50 MPH IN THE LAST
COUPLE OF HOURS...BUT DO NOT EXPECT WARNING CRITERIA GUSTS AS THE
MODELS SUGGEST WEAKENING FLOW ALOFT WITH TIME. A PRETTY UNEVENTFUL
SHORT TERM PERIOD ASIDE FROM BREEZY CONDITIONS TODAY. GFS/NAM/ECM
ARE IN EXCELLENT AGREEMENT WITH BROAD UPPER-LEVEL RIDGING BECOMING
ESTABLISHED ON MON/TUE. H7 TEMPS ARE PROGGED TO BE AROUND 5-7 DEG C
AT 00Z TUE. NO REAL CONCERNS ABOUT CIRRUS EITHER WITH FAIRLY DRY RH
PROGS BETWEEN H2-H3 PER THE GFS. ADIABATIC WARMING IS LIKELY WITH
GOOD SUBSIDENCE AND WESTERLY LLVL DOWNSLOPE...SO TEND TO FAVOR THE
WARMER MOS WITH HIGHS AROUND 65 F OVER THE PLAINS. COULD SEE A FEW
RECORDS THREATENED EARLY IN THE WORK WEEK. PCPN CHANCES WILL BE ON
THE INCREASE OVER THE FAR SOUTHWEST ON TUE NIGHT AHEAD OF A STRONG
SHORTWAVE LIFTING ACROSS CENTRAL UTAH.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MST SUN JAN 25 2015
UPPER RIDGE THAT GAVE US THE WARM TEMPERATURES STILL FORECAST TO
MOVE INTO EASTERN NEBRASKA WEDNESDAY MORNING. SHORTWAVE TROUGH
MOVES THROUGH WYOMING WEDNESDAY AFTERNOON FOR A RETURN OF COLDER
TEMPERATURES AND MOUNTAIN SNOW. BY WEDNESDAY AFTERNOON...GFS 700MB
TEMPERATURES FALL TO -6C...DOWN FROM +4C TUESDAY AFTERNOON.
GOING TO BE WINDY WITH THE ASSOCIATED COLD FRONT MOVING THROUGH
WEDNESDAY. GFS 700MB WINDS 45 TO 50KTS...SO LIKELY TO SEE WIND
HEADLINES FOR THE WIND PRONE AREAS. ABOUT .3 TO .4 INCHES QPF FOR
THE MOUNTAINS OUT WEST WITH THIS SYSTEM...SO COULD SEE ADVISORY
LEVEL SNOW AMOUNTS FOR THE SNOWY AND SIERRA MADRE RANGES.
ANOTHER WEAK SYSTEM FOR FRIDAY THAT WILL BRING SOME MORE LIGHT
SNOW AMOUNTS FOR THE MOUNTAINS. MOST EVERYWHERE ELSE SHOULD STAY
DRY WITH THIS SYSTEM.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 357 AM MST SUN JAN 25 2015
LATEST HRRR GUIDANCE FOR THE 12Z TAFS. LATEST 11-3.9U SATELLITE
IMAGERY SHOWS WIDESPREAD STRATUS OUT BY KRWL THIS MORNING. HRRR
SHOWS THE POTENTIAL FOR THIS STRATUS TO HANG IN AROUND KRWL FOR
MOST OF THE DAY. SOME BREAK UP BY MID MORNING SHOWN...SO WENT
SCT008 AFTER 15Z. VFR CONDITIONS ELSEWHERE.
&&
.FIRE WEATHER...
ISSUED AT 1257 AM MST SUN JAN 25 2015
NO MAJOR FIRE WEATHER CONCERNS. WARM TEMPERATURES AND LOCALLY BREEZY
CONDITIONS ARE LIKELY THROUGH MONDAY AFTERNOON. ALL PARAMETERS ARE
EXPECTED TO BE WELL BELOW CRITICAL THRESHOLDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...CLH
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
105 PM EST SUN JAN 25 2015
.SYNOPSIS...
A STRONG COLD FRONT WILL CONTINUE TO PUSH SOUTHEAST THROUGH OUR
REGION TODAY, REACHING A LATE DAY POSITION FROM THE DELMARVA WEST
INTO LOW PRESSURE OVER THE LOWER OHIO VALLEY. THAT LOW WILL REACH
THE NORTH CAROLINA COAST MONDAY MORNING THEN TURN NORTH NORTHEAST,
INTENSIFYING VERY RAPIDLY AS IT NEARS CAPE COD TUESDAY. HIGH
PRESSURE FOLLOWS BY LATE WEDNESDAY, THEN ANOTHER LOW WILL
REDEVELOP ON THE NEXT COLD FRONTAL PASSAGE OFF THE MID ATLANTIC
COAST LATE THURSDAY AND FRIDAY. HIGH PRESSURE FOLLOWS SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THE 12:30 PM UPDATE, WE HAVE INCREASED TEMPERATURES FROM PHL
SOUTH AHEAD OF A COLD FRONT ALONG WITH CLOUD COVER FOR THE
REMAINDER OF THE AFTERNOON. THIS CLOUD COVER SHOULD KEEP THE
TEMPERATURES IN CHECK FROM WARMING TO MUCH MORE AS THE DAY GOES
ON. THE LATEST RAP AND HRRR HOLD OFF ANY PRECIPITATION TILL THIS
EVENING, THIS FORECAST UPDATE TAKES OUT AMY MENTION OF
PRECIPITATION TILL THIS EVENING.
OTHERWISE, AS THE LOW PRESSURE FROM YESTERDAY PULLS FARTHER TO
OUR NORTHEAST AN ARCTIC-TYPE COLD FRONT PUSHES THROUGH OUR REGION
FROM LATE MORNING AND THROUGH THIS AFTERNOON. WATER VAPOR IMAGERY
THIS MORNING SHOWS ONE TROUGH AXIS TO OUR NORTHEAST WHILE ANOTHER
SHORTWAVE AXIS PUSHES THROUGH THE GREAT LAKES...THIS IS DRIVING
THE ARCTIC FRONT TODAY. WAY BACK ACROSS THE NORTHERN PLAINS IS THE
ENERGY THAT WILL BE THE DRIVING FORCE FOR THE CLIPPER SYSTEM LATE
TONIGHT AND THEN THE MUCH LARGER COASTAL NOR`EASTER EXPECTED ON
MONDAY- TUESDAY.
OVERALL A MAINLY DRY AND TRANQUIL DAY IS EXPECTED ACROSS THE
REGION. THE AFOREMENTIONED FRONT WILL SLIP THROUGH THE REGION BY
THIS AFTERNOON USHERING IN A COOLER AIRMASS. THE MORNING STRATOCU
SHOULD LIFT AND MIX OUT A LITTLE AS THE DAY WEARS ON. DECENT
DOWNSLOPING COMPONENT SHOULD ALLOW HIGHS TO REACH AROUND 40F THIS
AFTERNOON, SLIGHTLY WARMER SOUTH AND EAST OF PHILLY, AHEAD OF THE
FRONTAL PASSAGE. BEHIND THE FRONT WEAK MID-LEVEL WARM AIR
ADVECTION OCCURS TO OUR SOUTHWEST AS MORE MOISTURE AND CLOUDS
ADVECT IN BEGINNING LATER THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
BROAD SCALE SURFACE LOW PRESSURE, RIDING ALONG THE SAGGING COLD
FRONT LATER THIS EVENING, WILL PASS TO OUR SOUTH TONIGHT. HIGH
PRESSURE TO OUR NORTH WITH WEAK MID-LEVEL RIDGING WILL ALLOW FOR THE
MID-LEVEL SHORTWAVE DRIVING THE SURFACE LOW TO DEEPEN AND TAKE MORE
OF A NEGATIVE TILT TONIGHT. STRENGTHENING WAA, IN RESPONSE TO THIS
PROCESS, WILL OCCUR ACROSS OUR REGION AS A LIGHT SNOW SHOULD BREAK
OUT FROM WEST-EAST. ONSET TIMING IS STILL A BIT OF A QUESTION BUT A
MAJORITY OF THE HI-RES GUIDANCE IS SHOWING THE INCREASING CHANCES
DURING THE LATE EVENING. PTYPE SHOULD NOT BE MUCH OF AN ISSUE EXCEPT
ACROSS OUR EXTREME SOUTHERN ZONES AS LOW-LEVEL TEMPERATURES STRUGGLE
TO TRANSITION COLDER (BELOW 0C) JUST AHEAD OF THE APPROACHING
LOW...WAA SHOULD KEEP A RAIN/SNOW MIX SOUTH OF DOVER WHILE NORTHWARD
IS ALL SNOW.
DECENT CONVERGENCE ACROSS OUR CENTRAL ZONES LATE TONIGHT, BOTH
THERMALLY AND DYNAMICALLY. GUIDANCE IS PAINTING A NOSE OF A TENTH OF
LIQUID FROM A PHL/ABE LINE WEST SO THIS IS WHERE WE SHOULD SEE
SLIGHTLY HIGHER SNOW AMOUNTS...ON THE ORDER OF 1-2" IN AND AROUND
PHILLY, 2-3" FARTHER WEST TOWARDS RDG...MESOSCALE BANDING POTENTIAL
ALSO EXISTS ALBEIT NOT NEARLY AS ROBUST AS SATURDAY MORNING.
EVEN THOUGH THIS SNOW WILL AFFECT THE MONDAY MORNING COMMUTE WE DID
NOT WANT TO ADD TO ANY CONFUSION WITH MULTIPLE WINTER WEATHER
HEADLINES DEALING WITH THE SAME EVENT...JUST TWO DIFFERENT PIECES OF
ENERGY. GIVEN WE ARE EXPECTING A MUCH MORE IMPACTFUL STORM BEGINNING
LATER ON MONDAY...SEE LONG TERM DISCO...WE DECIDED TO FORGO AN
ADVISORY BUT MAKE MENTION OF THE EARLY MORNING SNOWFALL IN THE
HWO/WSW PRODUCTS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
**MAJOR DISRUPTIVE SNOWSTORM POTENTIAL LATE MONDAY INTO TUESDAY
MORNING PHILLY AREA NEWD TO NEW ENGLAND...WINTER STORM WATCH IN
PLACE FOR MOST OF THE FORECAST AREA**
**BLIZZARD WATCH HAS BEEN ISSUED FOR MONMOUTH, OCEAN, AND
MIDDLESEX COUNTIES**
500 MB: A STRONG SHORT WAVE MONDAY MORNING OVER THE CENTRAL APPALACHIANS
INTENSIFIES INTO A CLOSED LOW SOUTH OF LONG ISLAND TUESDAY. RIDGING
IN THE WAKE OF ITS MARITIMES DEPARTURE FOLLOWS TO THE EAST COAST
WEDNESDAY. A SOUTHEASTWARD MOVING SHORT WAVE REACHES THE MID
ATLANTIC COAST FRIDAY WITH A TEMPORARILY FLATTENED WESTERLY FLOW
NEXT WEEKEND.
TEMPERATURES (ENERGY USE): BELOW NORMAL MONDAY THROUGH THURSDAY,
POSSIBLY 5 TO 10 DEGREES BELOW MON-WED; NEAR NORMAL FRI, CHILLING
AGAIN SATURDAY.
FORECAST BASIS: UNLESS OTHERWISE NOTED WITHIN THE DAILIES. THIS
FORECAST IS A 50 50 BLEND OF THE 00Z/25 MAV/MET FOR MONDAY-TUESDAY.
THE 00Z/25 MEX MOS WAS APPLIED TUESDAY NIGHT AND WEDNESDAY. THE 05Z/25
WPC D4-8 ELEMENTS OF DEWPOINTS/WIND/SKY/POP/MAX-MIN TEMPS WERE NOT USED
FOR THE LONGER RANGE DUE TO FOCUS ON THE POTENTIALLY VERY HIGH IMPACT
STORM FOR MONDAY NIGHT.
THEREFORE...THERE WAS NO UPDATE OF THE FORECAST BEYOND WEDNESDAY
IN THE EARLY ISSUANCE TODAY.
THE DAILIES...
MONDAY-TUESDAY...WSA IN DIFFERING SEGMENTS TO BE REFINED WHEN
WATCHES CONVERT TO WARNINGS AND OR ADVISORIES.
MODEL DISAGREEMENT FOR THE 00Z/25 CYCLE WITH THE NAM THE MAIN OUTLIER
RIGHT NOW. THE UKMET IS LARGE BUT A FASTER DEPARTURE THAN THE ECMWF.
THE 00Z/06ZNAM WAS ACCEPTABLE THROUGH MIDDAY MONDAY AND THEREAFTER
DID NOT RELY ON THE NAM FOR ITS QPF...INSTEAD THIS FORECAST IS
BASED HEAVILY ON NCEP QPF/SNOWFALL AS WELL AS THE 00Z/25 ECMWF
AND GFS BLEND.
MONDAY: SEVERAL INCHES OF SNOW EXPECTED BUT AN ADVISORY NOT ISSUED
SINCE WE DID NOT WISH TO DRAW ATTENTION AWAY FROM THE POTENTIALLY
VERY HIGH IMPACT EVENT FOR MONDAY NIGHT. TOO WARM FOR MUCH ACCUMULATION
FAR SNJ AND MUCH OF THE DELMARVA. THE ARCTIC FRONT AND ITS SLOWLY
DEEPENING BOUNDARY LAYER COLD IS CRUCIAL FOR THE LIFT OF THE SELY
850MB FLOW AND A GENERAL SNOW IN EASTERN PA/MUCH OF NJ. COMMUTES
IMPACTED. HIGH CONFIDENCE.
MONDAY NIGHT INTO TUESDAY MORNING...UNCERTAINTY ON AMOUNTS ETC ALL
HINGING ON INTENSITY AND TRACK OF A COASTAL STORM. OVERALL, THIS
LOOKS LIKE A MAJOR STORM FOR US AND POTENTIAL FOR BLIZZARD CONDITIONS
IN NE NJ. OUR FORECAST AMOUNTS ARE PROBABLY CONSERVATIVE.
BANDING IN THE COMMA HEAD WITH A BENT BACK FRONT ALOFT LOOKS TO BE
A MAJOR PLAYER...GENERATING SNOWFALL RATES MONDAY NIGHT POSSIBLY
IN EXCESS OF AN INCH AN HOUR ACROSS NJ AND PORTIONS OF E PA. IF
THE 00Z/06Z NAM MASS FIELDS ALOFT ARE CORRECT THEN ALL THIS HEAVY SNOW
WOULD MISS TO THE EAST.
THOSE WITH TRAVEL PLANS IN E PA AND NJ ESPECIALLY FOR MONDAY NIGHT
AND TUESDAY SHOULD BE AWARE THAT THOSE PLANS MAY NEED MAJOR
ALTERATION/CANCELLATION. BE PREPARED WITH ALTERNATE PLANS. "IF"
CONFIDENCE IS VERY HIGH, WE MAY CONVERT TO WARNINGS LATE TODAY.
WATCHES DO NOT MEAN A DONE DEAL BUT DO PAY ATTENTION. A DRIER
MORE POWDERY SNOW WILL BE EASIER TO ACCUMULATE IN THE COLDER
AIRMASS THAN JUST WHAT OCCURRED EARLY SATURDAY. WIND WILL BECOME A
FACTOR IN BLOWING/DRIFTING, MAINLY IN NJ/DEL.
TUE NIGHT THRU WED NIGHT... HIGH PRESSURE WILL DOMINATE DURING THIS
PERIOD WITH FAIR BUT COLD WEATHER EXPECTED.
THU INTO FRI...THIS FORECAST WAS NOT UPDATED ON THIS MID SHIFT.
MODELS ARE SHOWING ANOTHER CLIPPER TYPE SYSTEM APPROACHING FROM
THE WEST AFTER THE MID WEEK PERIOD. TEMPERATURES WILL HAVE BEGUN
TO MODERATE BY THE TIME THE PRECIP ARRIVES...SO SOME RAIN/SNOW
LINE ISSUES WILL OCCUR. MOSTLY USED CHC POPS FOR NOW. TEMPS WILL
STILL BE BELOW NORMAL...BUT NOT AS COLD AS WED.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR CIGS AOA 4000 FT. STRATOCU DECK WILL REMAIN IN PLACE
MOST OF THE DAY UNDER WESTERLY WINDS WITH A FEW GUSTS POSSIBLE TO
NEAR 20 KT.
TONIGHT...MVFR/IFR IN AREAS OF SNOW. TIMING IS STILL A BIT SUSPECT
BUT LIGHT SNOW SHOULD OVERSPREAD FROM THE WEST-EAST BY LATE TONIGHT.
MINIMAL RAIN/SNOW MIXING EXPECTED VCNTY KMIV TOWARD 12Z MONDAY.
EXPECT SOME LIGHT ACCUMULATIONS THROUGH EARLY MONDAY MORNING...AROUND
1-2 INCHES PHL/ILG/TTN/PNE, MAYBE 2-3 INCHES RDG/ABE.
OUTLOOK...
MON AND MON NIGHT...IFR/LIFR SOUTH AND MVFR OR INTERMITTENT IFR
NORTH IN SNOW OR PERIODS OF SNOW. N-NE WINDS GUSTING 20-30 KT AT
TIMES WITH 35 KT GUSTS POSSIBLE VCNTY KACY. VERY HIGH CONFIDENCE.
PLOWABLE AMOUNTS AND POTENTIAL FOR AIRPORT CLOSURES AT NIGHT INTO
EARLY TUESDAY DEPENDENT ON SNOW AMOUNTS AND RATE OF FALL AS WELL
AS DRIFTING.
TUE...IFR PROBABLE EARLY IN COMMA HEAD BENT BACK BANDING OF THE BIG
NOREASTER THEN PROBABLY BECOMING VFR BY LATE IN THE DAY. NORTHWEST
WINDS GUSTING 20-30KT, EXCEPT POSSIBLY STRONGER VCNTY KACY.
AVERAGE CONFIDENCE.
TUESDAY NIGHT-WED: MOSTLY VFR. N-NW WINDS. HIGH CONFIDENCE:
THURSDAY: CONDITIONS MAY DEGRADE IN A PERIOD OF PCPN DURING THE
AFTERNOON OR NIGHT.
&&
.MARINE...
REST OF TODAY...WE REMOVED THE SCA FROM THE OCEAN FRONT AS WINDS AND
SEAS HAVE FALLEN BELOW THRESHOLDS.
TONIGHT...SUB-SCA EXPECTED. LOW PRESSURE WILL MOVE BY TO OUR SOUTH
LATE AS WINDS VEER TOWARDS THE NORTH-NORTHEAST. SEAS BEGIN TO BUILD
ACROSS THE SOUTHERN WATERS LATE AS DO THE WINDS. GALE WARNINGS/STORM
WATCHES IN PLACE STARTING MONDAY AFTERNOON.
OUTLOOK...
MONDAY INTO TUESDAY...MOSTLY GALE CONDITIONS ON THE WATERS BUT POCKETS
OF STORM FORCE GUSTS. HAVE FORECAST WHERE THE STORM FORCE 50 KT GUSTS
OVER THE NJ WATER WHERE THEY ARE MOST LIKELY TO OCCUR, BUT WITH THE
UNDERSTANDING THAT ISOLATED STORM FORCE GUSTS MAY OCCUR IN THE
DELAWARE WATERS AS WELL. THE HEADLINES ARE THE MOST LIKELY WORST
CASE SCENARIO.
TUESDAY AFTERNOON THROUGH THURSDAY...MAINLY SCA CONDITIONS WITH
AREAS OF FREEZING SPRAY EXPECTED.
&&
.TIDES/COASTAL FLOODING...
ANOTHER NORTHEASTER IS EXPECTED TO AFFECT THE COASTAL WATERS OF
DELAWARE AND NEW JERSEY FROM MONDAY NIGHT INTO TUESDAY. MINOR TO
POSSIBLY MODERATE TIDAL FLOODING SHOULD OCCUR AROUND THE TIMES OF
HIGH TIDE, MAINLY THE MIDNIGHT TUESDAY MORNING HIGH TIDE CYCLE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR PAZ054-055-060>062-070-071-101>106.
NJ...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR NJZ001-007>010-015>019-027.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR NJZ021>025.
BLIZZARD WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING
FOR NJZ012>014-020-026.
DE...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR DEZ001.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR DEZ002>004.
MD...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR MDZ008.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR MDZ012-015-019-020.
MARINE...STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING FOR
ANZ450>453.
GALE WARNING FROM 11 AM MONDAY TO 11 AM EST TUESDAY FOR ANZ431-
454-455.
GALE WARNING FROM 5 PM MONDAY TO 11 AM EST TUESDAY FOR ANZ430.
&&
$$
SYNOPSIS...DRAG/KLINE
NEAR TERM...GAINES/HEAVENER/KLINE
SHORT TERM...HEAVENER
LONG TERM...DRAG/KLINE
AVIATION...DRAG/HEAVENER/KLINE
MARINE...DRAG/HEAVENER/KLINE
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1233 PM EST SUN JAN 25 2015
.SYNOPSIS...
A STRONG COLD FRONT WILL CONTINUE TO PUSH SOUTHEAST THROUGH OUR
REGION TODAY, REACHING A LATE DAY POSITION FROM THE DELMARVA WEST
INTO LOW PRESSURE OVER THE LOWER OHIO VALLEY. THAT LOW WILL REACH
THE NORTH CAROLINA COAST MONDAY MORNING THEN TURN NORTH NORTHEAST,
INTENSIFYING VERY RAPIDLY AS IT NEARS CAPE COD TUESDAY. HIGH
PRESSURE FOLLOWS BY LATE WEDNESDAY, THEN ANOTHER LOW WILL
REDEVELOP ON THE NEXT COLD FRONTAL PASSAGE OFF THE MID ATLANTIC
COAST LATE THURSDAY AND FRIDAY. HIGH PRESSURE FOLLOWS SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THE 12:30 PM UPDATE, WE HAVE INCREASED TEMPERATURES FROM PHL
SOUTH AHEAD OF A COLD FRONT ALONG WITH CLOUD COVER FOR THE
REMAINDER OF THE AFTERNOON. THIS CLOUD COVER SHOULD KEEP THE
TEMPERATURES IN CHECK FROM WARMING TO MUCH MORE AS THE DAY GOES
ON. THE LATEST RAP AND HRRR HOLD OFF ANY PRECIPITATION TILL THIS
EVENING, THIS FORECAST UPDATE TAKES OUT AMY MENTION OF
PRECIPITATION TILL THIS EVENING.
OTHERWISE, AS THE LOW PRESSURE FROM YESTERDAY PULLS FARTHER TO
OUR NORTHEAST AN ARCTIC-TYPE COLD FRONT PUSHES THROUGH OUR REGION
FROM LATE MORNING AND THROUGH THIS AFTERNOON. WATER VAPOR IMAGERY
THIS MORNING SHOWS ONE TROUGH AXIS TO OUR NORTHEAST WHILE ANOTHER
SHORTWAVE AXIS PUSHES THROUGH THE GREAT LAKES...THIS IS DRIVING
THE ARCTIC FRONT TODAY. WAY BACK ACROSS THE NORTHERN PLAINS IS THE
ENERGY THAT WILL BE THE DRIVING FORCE FOR THE CLIPPER SYSTEM LATE
TONIGHT AND THEN THE MUCH LARGER COASTAL NOR`EASTER EXPECTED ON
MONDAY- TUESDAY.
OVERALL A MAINLY DRY AND TRANQUIL DAY IS EXPECTED ACROSS THE
REGION. THE AFOREMENTIONED FRONT WILL SLIP THROUGH THE REGION BY
THIS AFTERNOON USHERING IN A COOLER AIRMASS. THE MORNING STRATOCU
SHOULD LIFT AND MIX OUT A LITTLE AS THE DAY WEARS ON. DECENT
DOWNSLOPING COMPONENT SHOULD ALLOW HIGHS TO REACH AROUND 40F THIS
AFTERNOON, SLIGHTLY WARMER SOUTH AND EAST OF PHILLY, AHEAD OF THE
FRONTAL PASSAGE. BEHIND THE FRONT WEAK MID-LEVEL WARM AIR
ADVECTION OCCURS TO OUR SOUTHWEST AS MORE MOISTURE AND CLOUDS
ADVECT IN BEGINNING LATER THIS EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
BROAD SCALE SURFACE LOW PRESSURE, RIDING ALONG THE SAGGING COLD
FRONT LATER THIS EVENING, WILL PASS TO OUR SOUTH TONIGHT. HIGH
PRESSURE TO OUR NORTH WITH WEAK MID-LEVEL RIDGING WILL ALLOW FOR THE
MID-LEVEL SHORTWAVE DRIVING THE SURFACE LOW TO DEEPEN AND TAKE MORE
OF A NEGATIVE TILT TONIGHT. STRENGTHENING WAA, IN RESPONSE TO THIS
PROCESS, WILL OCCUR ACROSS OUR REGION AS A LIGHT SNOW SHOULD BREAK
OUT FROM WEST-EAST. ONSET TIMING IS STILL A BIT OF A QUESTION BUT A
MAJORITY OF THE HI-RES GUIDANCE IS SHOWING THE INCREASING CHANCES
DURING THE LATE EVENING. PTYPE SHOULD NOT BE MUCH OF AN ISSUE EXCEPT
ACROSS OUR EXTREME SOUTHERN ZONES AS LOW-LEVEL TEMPERATURES STRUGGLE
TO TRANSITION COLDER (BELOW 0C) JUST AHEAD OF THE APPROACHING
LOW...WAA SHOULD KEEP A RAIN/SNOW MIX SOUTH OF DOVER WHILE NORTHWARD
IS ALL SNOW.
DECENT CONVERGENCE ACROSS OUR CENTRAL ZONES LATE TONIGHT, BOTH
THERMALLY AND DYNAMICALLY. GUIDANCE IS PAINTING A NOSE OF A TENTH OF
LIQUID FROM A PHL/ABE LINE WEST SO THIS IS WHERE WE SHOULD SEE
SLIGHTLY HIGHER SNOW AMOUNTS...ON THE ORDER OF 1-2" IN AND AROUND
PHILLY, 2-3" FARTHER WEST TOWARDS RDG...MESOSCALE BANDING POTENTIAL
ALSO EXISTS ALBEIT NOT NEARLY AS ROBUST AS SATURDAY MORNING.
EVEN THOUGH THIS SNOW WILL AFFECT THE MONDAY MORNING COMMUTE WE DID
NOT WANT TO ADD TO ANY CONFUSION WITH MULTIPLE WINTER WEATHER
HEADLINES DEALING WITH THE SAME EVENT...JUST TWO DIFFERENT PIECES OF
ENERGY. GIVEN WE ARE EXPECTING A MUCH MORE IMPACTFUL STORM BEGINNING
LATER ON MONDAY...SEE LONG TERM DISCO...WE DECIDED TO FORGO AN
ADVISORY BUT MAKE MENTION OF THE EARLY MORNING SNOWFALL IN THE
HWO/WSW PRODUCTS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
**MAJOR DISRUPTIVE SNOWSTORM POTENTIAL LATE MONDAY INTO TUESDAY
MORNING PHILLY AREA NEWD TO NEW ENGLAND...WINTER STORM WATCH IN
PLACE FOR MOST OF THE FORECAST AREA**
**BLIZZARD WATCH HAS BEEN ISSUED FOR MONMOUTH, OCEAN, AND
MIDDLESEX COUNTIES**
500 MB: A STRONG SHORT WAVE MONDAY MORNING OVER THE CENTRAL APPALACHIANS
INTENSIFIES INTO A CLOSED LOW SOUTH OF LONG ISLAND TUESDAY. RIDGING
IN THE WAKE OF ITS MARITIMES DEPARTURE FOLLOWS TO THE EAST COAST
WEDNESDAY. A SOUTHEASTWARD MOVING SHORT WAVE REACHES THE MID
ATLANTIC COAST FRIDAY WITH A TEMPORARILY FLATTENED WESTERLY FLOW
NEXT WEEKEND.
TEMPERATURES (ENERGY USE): BELOW NORMAL MONDAY THROUGH THURSDAY,
POSSIBLY 5 TO 10 DEGREES BELOW MON-WED; NEAR NORMAL FRI, CHILLING
AGAIN SATURDAY.
FORECAST BASIS: UNLESS OTHERWISE NOTED WITHIN THE DAILIES. THIS
FORECAST IS A 50 50 BLEND OF THE 00Z/25 MAV/MET FOR MONDAY-TUESDAY.
THE 00Z/25 MEX MOS WAS APPLIED TUESDAY NIGHT AND WEDNESDAY. THE 05Z/25
WPC D4-8 ELEMENTS OF DEWPOINTS/WIND/SKY/POP/MAX-MIN TEMPS WERE NOT USED
FOR THE LONGER RANGE DUE TO FOCUS ON THE POTENTIALLY VERY HIGH IMPACT
STORM FOR MONDAY NIGHT.
THEREFORE...THERE WAS NO UPDATE OF THE FORECAST BEYOND WEDNESDAY
IN THE EARLY ISSUANCE TODAY.
THE DAILIES...
MONDAY-TUESDAY...WSA IN DIFFERING SEGMENTS TO BE REFINED WHEN
WATCHES CONVERT TO WARNINGS AND OR ADVISORIES.
MONMOUTH AND OCEAN COUNTIES OF NE NJ ARE SEPARATED AS WINTER STORM
WATCH, BUT READY TO TO CONVERT TO A BLIZZARD WARNING IF THREE
SUCCESSIVE RUNS OF THE ECMWF OPERATIONAL AND ENSEMBLE SOLUTIONS
ARE CORRECT.
MODEL DISAGREEMENT FOR THE 00Z/25 CYCLE WITH THE NAM THE MAIN OUTLIER
RIGHT NOW. THE UKMET IS LARGE BUT A FASTER DEPARTURE THAN THE ECMWF.
THE 00Z/06ZNAM WAS ACCEPTABLE THROUGH MIDDAY MONDAY AND THEREAFTER
DID NOT RELY ON THE NAM FOR ITS QPF...INSTEAD THIS FORECAST IS
BASED HEAVILY ON NCEP QPF/SNOWFALL AS WELL AS THE 00Z/25 ECMWF
AND GFS BLEND.
MONDAY: SEVERAL INCHES OF SNOW EXPECTED BUT AN ADVISORY NOT ISSUED
SINCE WE DID NOT WISH TO DRAW ATTENTION AWAY FROM THE POTENTIALLY
VERY HIGH IMPACT EVENT FOR MONDAY NIGHT. TOO WARM FOR MUCH ACCUMULATION
FAR SNJ AND MUCH OF THE DELMARVA. THE ARCTIC FRONT AND ITS SLOWLY
DEEPENING BOUNDARY LAYER COLD IS CRUCIAL FOR THE LIFT OF THE SELY
850MB FLOW AND A GENERAL SNOW IN EASTERN PA/MUCH OF NJ. COMMUTES
IMPACTED. HIGH CONFIDENCE.
MONDAY NIGHT INTO TUESDAY MORNING...UNCERTAINTY ON AMOUNTS ETC ALL
HINGING ON INTENSITY AND TRACK OF A COASTAL STORM. OVERALL, THIS
LOOKS LIKE A MAJOR STORM FOR US AND POTENTIAL FOR BLIZZARD CONDITIONS
IN NE NJ. OUR FORECAST AMOUNTS ARE PROBABLY CONSERVATIVE.
BANDING IN THE COMMA HEAD WITH A BENT BACK FRONT ALOFT LOOKS TO BE
A MAJOR PLAYER...GENERATING SNOWFALL RATES MONDAY NIGHT POSSIBLY
IN EXCESS OF AN INCH AN HOUR ACROSS NJ AND PORTIONS OF E PA. IF
THE 00Z/06Z NAM MASS FIELDS ALOFT ARE CORRECT THEN ALL THIS HEAVY SNOW
WOULD MISS TO THE EAST.
THOSE WITH TRAVEL PLANS IN E PA AND NJ ESPECIALLY FOR MONDAY NIGHT
AND TUESDAY SHOULD BE AWARE THAT THOSE PLANS MAY NEED MAJOR
ALTERATION/CANCELLATION. BE PREPARED WITH ALTERNATE PLANS. "IF"
CONFIDENCE IS VERY HIGH, WE MAY CONVERT TO WARNINGS LATE TODAY.
WATCHES DO NOT MEAN A DONE DEAL BUT DO PAY ATTENTION. A DRIER
MORE POWDERY SNOW WILL BE EASIER TO ACCUMULATE IN THE COLDER
AIRMASS THAN JUST WHAT OCCURRED EARLY SATURDAY. WIND WILL BECOME A
FACTOR IN BLOWING/DRIFTING, MAINLY IN NJ/DEL.
TUE NIGHT THRU WED NIGHT... HIGH PRESSURE WILL DOMINATE DURING THIS
PERIOD WITH FAIR BUT COLD WEATHER EXPECTED.
THU INTO FRI...THIS FORECAST WAS NOT UPDATED ON THIS MID SHIFT.
MODELS ARE SHOWING ANOTHER CLIPPER TYPE SYSTEM APPROACHING FROM
THE WEST AFTER THE MID WEEK PERIOD. TEMPERATURES WILL HAVE BEGUN
TO MODERATE BY THE TIME THE PRECIP ARRIVES...SO SOME RAIN/SNOW
LINE ISSUES WILL OCCUR. MOSTLY USED CHC POPS FOR NOW. TEMPS WILL
STILL BE BELOW NORMAL...BUT NOT AS COLD AS WED.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR CIGS AOA 4000 FT. STRATOCU DECK WILL REMAIN IN PLACE
MOST OF THE DAY UNDER WESTERLY WINDS WITH SOME GUSTS EXPECTED TO
NEAR 20 KT WITH THE CFP LATER THIS MORNING.
TONIGHT...MVFR/IFR IN AREAS OF SNOW. TIMING IS STILL A BIT SUSPECT
BUT LIGHT SNOW SHOULD OVERSPREAD FROM THE WEST-EAST BY LATE TONIGHT.
MINIMAL RAIN/SNOW MIXING EXPECTED VCNTY KMIV TOWARD 12Z MONDAY.
EXPECT SOME LIGHT ACCUMULATIONS THROUGH EARLY MONDAY MORNING...AROUND
1-2 INCHES PHL/ILG/TTN/PNE, MAYBE 2-3 INCHES RDG/ABE.
OUTLOOK...
MON AND MON NIGHT...IFR/LIFR SOUTH AND MVFR OR INTERMITTENT IFR
NORTH IN SNOW OR PERIODS OF SNOW. N-NE WINDS GUSTING 20-30 KT AT
TIMES WITH 35 KT GUSTS POSSIBLE VCNTY KACY. VERY HIGH CONFIDENCE.
PLOWABLE AMOUNTS AND POTENTIAL FOR AIRPORT CLOSURES AT NIGHT INTO
EARLY TUESDAY DEPENDENT ON SNOW AMOUNTS AND RATE OF FALL AS WELL
AS DRIFTING.
TUE...IFR PROBABLE EARLY IN COMMA HEAD BENT BACK BANDING OF THE BIG
NOREASTER THEN PROBABLY BECOMING VFR BY LATE IN THE DAY. NORTHWEST
WINDS GUSTING 20-30KT, EXCEPT POSSIBLY STRONGER VCNTY KACY.
AVERAGE CONFIDENCE.
TUESDAY NIGHT-WED: MOSTLY VFR. N-NW WINDS. HIGH CONFIDENCE:
THURSDAY: CONDITIONS MAY DEGRADE IN A PERIOD OF PCPN DURING THE
AFTERNOON OR NIGHT.
&&
.MARINE...
TODAY...WE REMOVED THE SCA ON THE BAY AS WINDS AND SEAS ARE BELOW
THRESHOLDS. THE OCEAN FRONT CONTINUES TO GO THROUGH 18Z TODAY THOUGH
IT IS POSSIBLE THAT OUR SOUTHERN WATERS MAY BE PULLED SOONER AS SEAS
CONTINUE TO SUBSIDE THROUGHOUT THE MORNING.
TONIGHT...SUB-SCA EXPECTED. LOW PRESSURE WILL MOVE BY TO OUR SOUTH
LATE AS WINDS VEER TOWARDS THE NORTH-NORTHEAST. SEAS BEGIN TO BUILD
ACROSS THE SOUTHERN WATERS LATE AS DO THE WINDS. GALE WARNINGS/STORM
WATCHES IN PLACE STARTING MONDAY AFTERNOON.
OUTLOOK...
MONDAY INTO TUESDAY...MOSTLY GALE CONDITIONS ON THE WATERS BUT POCKETS
OF STORM FORCE GUSTS. HAVE FORECAST WHERE THE STORM FORCE 50 KT GUSTS
OVER THE NJ WATER WHERE THEY ARE MOST LIKELY TO OCCUR, BUT WITH THE
UNDERSTANDING THAT ISOLATED STORM FORCE GUSTS MAY OCCUR IN THE
DELAWARE WATERS AS WELL. THE HEADLINES ARE THE MOST LIKELY WORST
CASE SCENARIO.
TUESDAY AFTERNOON THROUGH THURSDAY...MAINLY SCA CONDITIONS WITH
AREAS OF FREEZING SPRAY EXPECTED.
&&
.TIDES/COASTAL FLOODING...
ANOTHER NORTHEASTER IS EXPECTED TO AFFECT THE COASTAL WATERS OF
DELAWARE AND NEW JERSEY FROM MONDAY NIGHT INTO TUESDAY. MINOR TO
POSSIBLY MODERATE TIDAL FLOODING SHOULD OCCUR AROUND THE TIMES OF
HIGH TIDE, MAINLY THE MIDNIGHT TUESDAY MORNING HIGH TIDE CYCLE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR PAZ054-055-060>062-070-071-101>106.
NJ...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR NJZ001-007>010-015>019-027.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR NJZ021>025.
BLIZZARD WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING
FOR NJZ012>014-020-026.
DE...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR DEZ001.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR DEZ002>004.
MD...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR MDZ008.
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR MDZ012-015-019-020.
MARINE...STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING FOR
ANZ450>453.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ450>455.
GALE WARNING FROM 11 AM MONDAY TO 11 AM EST TUESDAY FOR ANZ431-
454-455.
GALE WARNING FROM 5 PM MONDAY TO 11 AM EST TUESDAY FOR ANZ430.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...GAINES/HEAVENER/KLINE
SHORT TERM...HEAVENER
LONG TERM...DRAG/KLINE
AVIATION...DRAG/HEAVENER
MARINE...DRAG/HEAVENER
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
409 PM CST SUN JAN 25 2015
.SHORT TERM...
206 PM CST
TONIGHT THROUGH MONDAY NIGHT...
COOL AIR HAS STRUGGLED TO SLIDE SOUTH THIS AFTERNOON...HOWEVER TEMPS
ARE BEGINNING TO FALL INTO THE UPR 20S ACROSS FAR NORTHEAST IL.
ACROSS THE CENTRAL/SOUTHERN CWFA TEMPS REMAIN IN THE LOW 30S WITH
DEW POINT DEPRESSIONS NOT MUCH MORE THAN 1 TO 2 DEGREES. NORTH OF
I-80 PRECIP IS MAINLY FLURRIES...WITH A RAIN/SNOW MIX SLOWLY
CHANGING TO ALL SNOW LATER THIS AFTERNOON ACROSS THE SOUTHERN CWFA.
THE SHORTWAVE THAT BROUGHT THE LIGHT SNOW CONTINUES TO SLIDE EAST
ACROSS SOUTHERN IL...AND WILL STEADILY BRING AN END TO THE PRECIP
ACROSS THE FORECAST AREA THIS EVENING FROM NORTHWEST TO SOUTHEAST.
WINDS WILL GRADUALLY DIMINISH AS WELL AS THE PRESSURE GRADIENT
RELAXES.
SFC RIDGE CENTERED TO THE NORTH THIS AFTERNOON...WILL SAG SOUTH AND
EXPAND TO COVER A PORTION OF THE WESTERN GREAT LAKES/MISSOURI VALLEY
OVERNIGHT. WHILE SOME EROSION TO THE CLOUDS IS PROBABLE NORTH OF THE
FORECAST AREA...EXPECT SOME DECREASE IN CLOUDS CLOSER TO DAYBREAK
MON. CURRENTLY EXPECT OVERNIGHT LOWS TO DIP INTO THE MID/UPR
TEENS...HOWEVER THIS WILL LIKELY NOT OCCUR UNTIL CLOSER TO DAYBREAK
MON.
THE BRIEF BREAK IN CLOUDS MON MORNING WILL QUICKLY GIVE WAY TO THE
NEXT CLIPPER SYSTEM ARRIVING MON AFTN/EVE. GUIDANCE HAS MAINTAINED A
PROGRESSIVE LOOK TO THIS NEXT WAVE...HOWEVER OPERATIONAL SOLUTIONS
ARE EQUALLY BULLISH ON EROSION OF MOISTURE WITHIN THE LOWEST FEW
LAYERS OF THE ATMOS LATE MON NGT. HAVE SOME CONCERN ABOUT P-TYPE MON
AFTN/EVE. AT THE ONSET MOISTURE WILL QUICKLY SATURATE THRU THE -10
DEG C LAYER AND TOUCH THE FAVORED DGZ...HOWEVER THE DEPTH OF THE
MOISTURE BECOMES MORE SHALLOW MON EVE. ALONG WITH THE LACK OF GOOD
LIFT AND SHALLOW MOISTURE...IT IS LOOKING MORE LIKELY THAT PRECIP
MAY BE A MIX OF FREEZING DRIZZLE/LGT-SNOW.
A WEAK THERMAL RIDGE TRIES TO PUSH OVERHEAD MON AFTN...AS LLVL FLOW
TURNS SOUTHWESTERLY. TEMPS SHUD HOVER ARND FREEZING...HOWEVER THIS
WILL HINGE ON CLOUD COVER ARRIVAL AND DEVELOPMENT OF PRECIP. IF THIS
IS DELAYED...TEMPS COULD PUSH A FEW DEGREES WARMER MON EARLY AFTN.
HEIGHTS SLOWLY INCREASE MON NGT...WITH THE MOISTURE PEELING EAST
ALONG WITH THE WEAKENING SHORTWAVE. AT THIS TIME HAVE MAINTAINED A
MENTION OF LGT SNOW OR PATCHY FREEZING DRIZZLE MON NGT...BUT COULD
END UP WITH A DRY PERIOD.
BEACHLER
&&
.LONG TERM...
206 PM CST
TUESDAY THROUGH SUNDAY...
TOWARDS THE MIDDLE OF THE WEEK ENSEMBLES MAINTAIN A HIGH CONFIDENCE
IN THE TROUGH ALONG THE SOUTHEAST CONUS WEAKENING WITH RIDGING
EXPANDING EAST ACROSS THE CENTRAL PLAINS. THIS SHUD PLACE THE BULK
OF THE REGION INTO A WEAK SFC RIDGE TUE/WED. WED AFTN THE SFC RIDGE
QUICKLY SLIDES SOUTHEAST...WHICH COULD ALLOW SOME WARM AIR TO ADVECT
NORTHEAST INTO THE CWFA AND PUSH SFC TEMPS CLOSE TO 40 DEG.
WITH A QUASI-ZONAL SETUP WED NGT/THUR...GUIDANCE SUGGESTS A ROBUST
MID-LVL VORT WILL QUICKLY SLIDE EAST FROM THE ROCKIES TOWARDS THE
PLAINS WED EVE. GUIDANCE THEN FURTHER STRENGTHENS THIS WAVE AND
LIFTS NORTHEAST ACROSS THE FORECAST AREA THUR. SOUNDINGS SUGGESTS
THAT PRECIP COULD START AS MAINLY RAIN WITH THIS SYSTEM...THEN
DYNAMICALLY COOL OVERNIGHT INTO THUR AND TRANSITION PRECIP OVER TO
LGT SNOW.
A RELATIVELY ACTIVE PATTERN CONTINUES TOWARDS THE END OF THE WEEK
INTO EARLY NEXT WEEKEND...WITH TEMPS GENERALLY IN THE UPR 20S/LOW
30S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* MVFR CIGS UNTIL EARLY EVENING
* STRONG/GUSTY NORTHEAST WINDS UNTIL EARLY EVENING
* LIGHT SNOW LATE MONDAY AFTERNOON
IZZI
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE NEAR STL WILL SLOWLY TRACK EAST ACROSS THE OHIO
VALLEY THIS AFTERNOON INTO TONIGHT. AS IT DOES...LIGHT SNOW WILL
SLOWLY TAPER OFF TO FLURRIES. NORTHEAST WINDS OFF THE LAKE MAY
ALLOW SOME LIGHT SNOW SHOWERS TO CONTINUE NEAR THE LAKE BUT NOT
EXPECTING ANYTHING SIGNIFICANT. HAVE MAINTAINED MENTION OF VFR
LIGHT SNOW THROUGH EARLY EVENING THOUGH CONFIDENCE REGARDING END
TIME IS FAIRLY LOW. VISIBILITIES AND CIGS ARE SLOWLY TRENDING UP
AND THIS WILL CONTINUE THRU THE AFTERNOON WITH PREVAILING MVFR
EXPECTED. NORTHEAST WINDS WILL REMAIN STRONG AND GUSTY WITH GUSTS
INTO THE MID/UPPER 20 KT RANGE THROUGH LATE AFTERNOON WITH A SLOW
RELAXING OF THE SPEEDS/GUSTS THRU THE EVENING. A RIDGE AXIS WILL
MOVE ACROSS THE AREA TOWARD DAYBREAK WITH WINDS BECOMING LIGHT AND
VARIABLE AND THEN SWITCHING TO SOUTHERLY MID/LATE MONDAY MORNING.
A WEAK CLIPPER SYSTEM WILL MOVE SOUTHEAST ACROSS THE WESTERN LAKES
MONDAY AFTERNOON INTO MONDAY NIGHT AND WHILE THIS FEATURE HAS BEEN
CONSISTENT FOR A FEW DAYS...IT HAS LIMITED MOISTURE. HOWEVER...
THERE COULD BE A PERIOD OF LIGHT SNOW BY MID/LATE AFTERNOON ACROSS
NORTHERN IL THAT CONTINUES INTO MONDAY EVENING. THE CLOUD LAYERS
APPEAR DEEP ENOUGH FOR LIGHT SNOW BUT AS THE MID LEVELS DRY OUT IN
THE EVENING...PRECIP COULD TRANSITION TO LIGHT FREEZING DRIZZLE.
STILL SOME UNCERTAINTY HOW THIS PLAYS OUT...BUT OPTED TO INCLUDE A
PROB30 IN THE 30HR ORD TAF. CMS
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM FOR LIGHT SNOW MONDAY AFTERNOON...LOW FOR ASSOCIATED
CIGS/VIS.
* HIGH CONFIDENCE IN REMAINING FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...CHANCE LIGHT SNOW/MVFR.
TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MAINLY VFR DURING THE DAY THEN CHANCE OF -RASN AND
MVFR/IFR AT NIGHT.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF MVFR CIGS.
SATURDAY...CHANCE OF LIGHT SNOW/MVFR.
RATZER
&&
.MARINE...
131 PM CST
A QUICK MOVING CLIPPER SYSTEM...CURRENTLY CENTERED ACROSS SOUTHERN
ILLINOIS...WILL RAPIDLY SHIFT EASTWARD TOWARDS THE ATLANTIC COAST
BY MONDAY MORNING. NORTHEASTERLY WINDS OF 30-35 KT CONTINUE ACROSS
THE SOUTHERN 1/3RD OF LAKE MICHIGAN...AND THESE WINDS LOOK TO
CONTINUE FOR THE NEXT FEW HOURS...BEFORE A DIMINISHING TREND BEGINS
EARLY THIS EVENING. ANOTHER WEAKENING LOW WILL SHIFT SOUTHWARD JUST
WEST OF THE LAKE LATE MONDAY AND MONDAY NIGHT. THIS WILL RESULT IN A
PERIOD OF SOUTHERLY WINDS OVER THE LAKE DURING THIS PERIOD. LATER IN
THE WEEK ANOTHER LOW IS EXPECTED TO IMPACT THE GREAT LAKES REGION.
THIS SYSTEM STILL HAS THE POTENTIAL TO PRODUCE A PERIOD OF STRONG
SOUTHERLY WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT...FOLLOWED BY A
PERIOD OF STRONG NORTHERLY WINDS THURSDAY INTO EARLY FRIDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ673-LMZ675-LMZ740-LMZ741-LMZ742-LMZ743-
LMZ744-LMZ745-LMZ777-LMZ779-LMZ874-LMZ876-LMZ878 UNTIL 6 PM
SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 9 AM MONDAY.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
240 PM CST Sun Jan 25 2015
.SHORT TERM...(Tonight)
ISSUED AT 239 PM CST SUN JAN 25 2015
Area of low pressure which has brought our precipitation was
centered near Carbondale early this afternoon. Rain/snow transition
line has been struggling to move any further south, and in fact
areas from Macomb to Bloomington which had switched over were
starting to mix with rain again. Temperatures have been above
freezing over most of the snow area and accumulations have been
minor and slushy, but some more substantial 1-2 inch totals have
occurred north of Galesburg where temperatures are now below
freezing. The deformation band of snow has been weakening some the
last few hours, and there is a substantial hole in the precip over
the central 2/3 of the forecast area.
The RAP model shows a further weakening of the the deformation band
over the next few hours, and actually has the entire CWA dry by 6
pm. Have some concerns that may be too quick across the southeast,
as the upper wave continues to dig across southeast Missouri, and
have lingered some likely PoP`s down there slightly beyond that time
frame, but reduced PoP`s to below 20% by 9 pm.
Overnight, models are trying to show some substantial clearing over
most of the forecast area beginning late evening. While there is
some breakup of the clouds upstream across Wisconsin, it is not
completely clear up there and the north/northeast flow is not
especially conducive to rapid clearing. Have gone with partly cloudy
skies overnight across the northwest half of the forecast area, but
clouds will already been increasing ahead of the next clipper which
will be dropping southeast into northern Minnesota overnight.
&&
.LONG TERM...(Monday through Sunday)
ISSUED AT 239 PM CST SUN JAN 25 2015
A couple of cooler days are on tap across central and southeast
Illinois in the wake of today`s clipper. There is still a chance we
may see a few snow flakes or sprinkles on Monday as a shearing
upper-level wave, currently diving across the Canadian Prairies,
passes through the Great Lakes region and parts of the Midwest.
However, looking at forecast soundings, there will be a very small
window of opportunity where ice crystals will be present, suggesting
the chance of measurable precipitation is quite low. So, for now,
will only carry a chance of flurries Monday across the northern
portion of the forecast area as the very sheared wave passes to our
north. It is definitely possible that we will see nothing at all, or
perhaps some light drizzle or freezing drizzle (depending on surface
temperatures) due to the paucity of ice crystals.
Temperatures will warm heading into midweek as the persistent
amplified upper-level flow briefly turns more zonal, and a system
approaches from the Pacific coast. This system will mainly pose a
rain threat as it moves through Wednesday night into Thursday. A
brief period of snow is not out of the question later Thursday as
cold air filters in behind the system, but forecast soundings
currently suggest the moisture depth will be too shallow to support
precipitation (no ice crystals) by the time the thermal profile
would support snow.
Another cool down is expected in the wake of the midweek system, but
temperatures should still be near normal for late January. The
eastern North American mean trof that has been in place will try to
reestablish itself by the weekend. A clipper type wave in the
returning northwest upper-level flow may bring a chance of snow to
the area over the weekend. However, the current storm track keeps
the best snow chances to our north, and have only included a slight
chance of snow at this time.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1128 AM CST SUN JAN 25 2015
Several challenges with this TAF set. Widespread precipitation
north of a KIJX-KDNV line has been changing from rain to snow.
Radar data indicates the transition line is just south of KBMI to
about 30SW KPIA, although a bit of mixed precipitation has also
been reported near KCMI. Still seeing temperatures in the upper
30s to lower 40s from KSPI-KCMI so the transition is still a
couple hours away. High-resolution model data suggests some
erosion in the precip shield as the afternoon goes on, as a
surface low travels through the southern tip of the state, so most
of the TAF sites should see the precip end by 00Z. Strong
northeast winds kicking in on the north flank of the low
circulation, so winds 25-30 knots will be spreading over the TAF
sites over the next couple hours and persist much of the evening.
IFR/LIFR conditions will be occurring as the snow moves through.
Some improvement expected this evening, but have largely kept MVFR
ceilings at all TAF sites through the night, as the wind flow does
not favor rapid clearing. Did scatter out KPIA for a time after
06Z, as suggested by a narrow clear slot on the RAP model. Winds
to turn more southwesterly Monday morning ahead of a storm system
which will pass to our north.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Bak
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1158 AM CST SUN JAN 25 2015
.SHORT TERM...
329 AM CST
THROUGH TONIGHT...
HAVE FURTHERED THE DIMINISHING SNOWFALL TREND IN THE FORECAST FOR
TODAY...MAINLY NORTH OF INTERSTATE 80. ACROSS THE ENTIRE AREA THIS
LOOKS TO BE A MAINLY LOW IMPACT...NUISANCE TYPE SNOW...WITH SOME
COMMUNITIES IN THE NORTH QUITE POSSIBLY NOT SEEING ANY
ACCUMULATION. HAVE CONTINUED A SPECIAL WEATHER STATEMENT FOR AREAS
ALONG AND SOUTH OF I-80.
SATELLITE IMAGERY THIS MORNING DEPICTS THE CLOSED UPPER CIRCULATION
ACROSS WESTERN IA WITH AN AREA OF COOLING CLOUD TOPS IN ADVANCE OF
THIS MOVING INTO NORTHWEST IL. THIS IS CORRELATING WITH MAINLY LIGHT
RAIN OR RAIN/SNOW MIX IN THE SMALL WINDOW OF DEEPER MOIST
ADVECTION AHEAD OF THE LOW. SIMPLE EXTRAPOLATION OF THE CURRENT
AREA OF PRECIP IN IOWA AND THE DEVELOPING DEFORMATION ON THE
BACKSIDE CLEARLY INDICATE THE SOUTHERN CWA IS MORE SUPPORTED FOR
PRECIPITATION THAN THE NORTH. AT THE SURFACE...TEMPERATURES ARE
AROUND OR JUST ABOVE FREEZING ACROSS MUCH OF THE FORECAST AREA. A
DEVELOPING COLD FRONT IS ADVANCING SOUTHWARD INTO NORTHERN IL WITH
DEW POINTS IN THE MID TO UPPER 20S NORTH OF THIS FEATURE...ANOTHER
HINDRANCE OF APPRECIABLE PRECIPITATION IN NORTHERN AREAS OF THE
FORECAST AREA.
SHORT RANGE GUIDANCE LIKE ITS LONG RANGE COUNTERPARTS THE PAST
SEVERAL DAYS SHOW A FAIR AMOUNT OF DISCREPANCY...NAMELY ON COVERAGE
OF PRECIP TODAY AND PRECIP TYPE IN THE SOUTHERN CWA THIS
MORNING...BUT THEY LEND SUPPORT TO THE OBSERVATIONAL TRENDS. AS
THE AREA OF RAIN ASSOCIATED WITH ELEVATED ISENTROPIC ASCENT MOVES
INTO THE SOUTHERN FORECAST AREA...PROFILES SUPPORT A PERIOD OF
RAIN OR MIX INITIALLY...AND SOME LOCATIONS MIGHT HAVE AIR
TEMPERATURES RIGHT AT FREEZING. WOULD EXPECT ANY FREEZING RAIN
THREAT TO BE SHORT LIVED AS PROFILES TREND TOWARD SNOW. MESOSCALE
CONVERGENCE AND BAROCLINIC FORCING FOR INDUCED LIFT WOULD BECOME
MORE FAVORED JUST TO THE NORTHEAST OF THE CLOSED 850MB
CIRCULATION AS IT PIVOTS MORE EASTWARD. THAT IS FAVORED ACROSS
THE SOUTHERN TIER OR TWO OF COUNTIES LATER THIS MORNING INTO
EARLY AFTERNOON. PROFILES ARE MILD FOR IDEAL SNOW GROWTH...AND
MAYBE EVEN FOR SNOW AT ALL DOWN TOWARD GIBSON CITY FOR MUCH OF THE
MORNING. HAVE SNOW TOTALS AROUND ONE TO TWO INCHES FROM PERU TO
RENSSELAER AND SOUTHWARD FOR TODAY...WITH SNOW DEPARTING NEAR OR
SOON AFTER SUNDOWN.
AS FOR AREAS NORTH OF INTERSTATE 80...SHOULD SEE A GRADUAL INCREASE
IN LIGHT SNOW AREAWIDE BY MID-MORNING. DRY CORRIDOR NEAR 850MB
SEEN ON EARLY MORNING AMDAR SOUNDINGS OVER CHICAGO SHOULD LIMIT
INTENSITY OF ANY SNOW IN THE NORTHERN FORECAST AREA...AS WILL JUST
LESS FORCING. AREAS OF NORTHEAST ILLINOIS STILL LOOK TO HAVE
ONSHORE FLOW BEHIND THE COLD FRONT...BUT FORECAST INVERSION
HEIGHTS AS WELL AS ADAPTED ONES FROM THE 00Z GRB RAOB LAST
EVE...INDICATE VERY MARGINAL DEPTH OF CONVECTIVE CLOUDS. THUS NOT
EXPECTING MUCH IF ANY ENHANCEMENT TO ALREADY MINIMAL SYNOPTIC
FORCING OVER NORTHEAST IL. COULD SEE SOME DISORGANIZED LIGHT SNOW
OR FLURRIES LATE THIS AFTERNOON INTO THIS EVENING AS PROFILES OF
THE LAKE INDUCED STRATOCU COOL INTO THE ICE INITIATION LAYER...BUT
THIS SHOULD NOT BE A BIG DEAL.
AREAWIDE THE NORTHEAST WINDS WILL INCREASE TO 30 MPH AND MAYBE EVEN
A LITTLE HIGHER JUST OF THE LAKE. WITH MINIMAL SNOW NORTH NOT
EXPECTING ANY BLOWING SNOW ISSUES...AND SOUTH THE LOW SNOW-TO-
LIQUID RATIOS SHOULD SUPPRESS MUCH FOR BLOWING ISSUES...THOUGH
COULD LEAD TO MORE REDUCED VISIBILITY DURING THE TIME OF FALLING
SNOW THIS AFTERNOON.
MTF
&&
.LONG TERM...
329 AM CST
MONDAY THROUGH SATURDAY...
THE DISTURBED FLOW PATTERN WILL TURN MORE NORTHWESTERLY MONDAY AND
TUESDAY AS A MAJOR SYSTEM IS EXPECTED TO DEVELOP OFF THE NORTHEAST
COAST. GIVEN THIS POSSIBLY LEADING TO A SLOWER PATTERN...AS WELL
AS THE TREND OF TODAYS SYSTEM...IT IS QUITE CONCEIVABLE THAT THE
NEXT DISTURBANCE FOR MONDAY AFTERNOON AND NIGHT TRENDS WEST AS
WELL...WHICH THE EC HAS HAD IN ITS SOLUTION FOR THREE CONSECUTIVE
RUNS. THIS SYSTEM THOUGH IS NOT AS STRONG AS TODAYS AS IT IS MORE
OF A SHEARED AREA OF VORTICITY ALONG THE LINGERING BAROCLINIC
ZONE. FORCING FOR PRECIP LOOKS PRETTY LIGHT ONCE AGAIN MONDAY
AFTERNOON AND NIGHT BUT ENOUGH TO GO A LITTLE HIGHER ON POPS FOR
NORTHERN PARTS OF THE FORECAST AREA. RIGHT NOW GUIDANCE IS IN
DECENT AGREEMENT WITH SATURATING DEEP ENOUGH FOR PRECIP TYPE TO BE
LIGHT SNOW IF IT CAN OCCUR...BUT NEED TO KEEP AN EYE OUT FOR SOME
FREEZING DRIZZLE POTENTIAL IN THESE LIGHT ASCENT SITUATIONS.
A SLOW MODERATION LOOKS TO OCCUR TUESDAY INTO WEDNESDAY AND THIS
COULD BE VERY MINIMAL DEPENDING ON CLOUD COVER WHICH REMAINS A BIG
QUESTION MARK. HAVE LEANED MORE CLOUDY TUESDAY BUT STILL THINK
WITH A WESTERLY PUSH WEDNESDAY WOULD HAVE SUN POTENTIAL. LONG
RANGE GUIDANCE INDICATES A PACIFIC SYSTEM TO BE THE NEXT ONE TO
POSSIBLY BRING PRECIPITATION TO THE AREA WEDNESDAY NIGHT INTO
THURSDAY. CONTINUE POPS DURING THIS TIME FRAME AND AT THIS POINT
PROFILES ARE NEAR THE BORDER FOR RAIN OR SNOW...SO DID NOT GET TOO
FANCY WITH THE FORECAST PRECIPITATION TYPE. BEHIND THIS SYSTEM IT
SEEMS FAVORED FOR TEMPERATURES TO COOL SOME DURING THE LATTER
HALF OF THE WEEK...TO SLIGHTLY BELOW NORMAL VALUES. OBVIOUSLY ANY
FRESH SNOW COVER WOULD HELP LEAN THAT MORE TOWARD BELOW NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT SNOW TAPERING TO FLURRIES THIS AFTERNOON.
* MVFR CIGS LIFTING THIS AFTERNOON THEN SCATTERING OUT TONIGHT.
* STRONG/GUSTY NORTHEAST WINDS THRU MID EVENING.
* LIGHT SNOW LATE MONDAY AFTERNOON. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE NEAR STL WILL SLOWLY TRACK EAST ACROSS THE OHIO
VALLEY THIS AFTERNOON INTO TONIGHT. AS IT DOES...LIGHT SNOW WILL
SLOWLY TAPER OFF TO FLURRIES. NORTHEAST WINDS OFF THE LAKE MAY
ALLOW SOME LIGHT SNOW SHOWERS TO CONTINUE NEAR THE LAKE BUT NOT
EXPECTING ANYTHING SIGNIFICANT. HAVE MAINTAINED MENTION OF VFR
LIGHT SNOW THROUGH EARLY EVENING THOUGH CONFIDENCE REGARDING END
TIME IS FAIRLY LOW. VISIBILITIES AND CIGS ARE SLOWLY TRENDING UP
AND THIS WILL CONTINUE THRU THE AFTERNOON WITH PREVAILING MVFR
EXPECTED. NORTHEAST WINDS WILL REMAIN STRONG AND GUSTY WITH GUSTS
INTO THE MID/UPPER 20 KT RANGE THROUGH LATE AFTERNOON WITH A SLOW
RELAXING OF THE SPEEDS/GUSTS THRU THE EVENING. A RIDGE AXIS WILL
MOVE ACROSS THE AREA TOWARD DAYBREAK WITH WINDS BECOMING LIGHT AND
VARIABLE AND THEN SWITCHING TO SOUTHERLY MID/LATE MONDAY MORNING.
A WEAK CLIPPER SYSTEM WILL MOVE SOUTHEAST ACROSS THE WESTERN LAKES
MONDAY AFTERNOON INTO MONDAY NIGHT AND WHILE THIS FEATURE HAS BEEN
CONSISTENT FOR A FEW DAYS...IT HAS LIMITED MOISTURE. HOWEVER...
THERE COULD BE A PERIOD OF LIGHT SNOW BY MID/LATE AFTERNOON ACROSS
NORTHERN IL THAT CONTINUES INTO MONDAY EVENING. THE CLOUD LAYERS
APPEAR DEEP ENOUGH FOR LIGHT SNOW BUT AS THE MID LEVELS DRY OUT IN
THE EVENING...PRECIP COULD TRANSITION TO LIGHT FREEZING DRIZZLE.
STILL SOME UNCERTAINTY HOW THIS PLAYS OUT...BUT OPTED TO INCLUDE A
PROB30 IN THE 30HR ORD TAF. CMS
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR LIGHT SNOW TAPERING TO FLURRIES THIS AFTERNOON...LOW
FOR SPECIFIC TIMING AND ASSOCIATED CIGS/VIS.
* MEDIUM FOR CIGS THRU THE PERIOD.
* HIGH FOR WINDS THRU THE PERIOD.
* MEDIUM FOR LIGHT SNOW MONDAY AFTERNOON...LOW FOR ASSOCIATED
CIGS/VIS. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...CHANCE LIGHT SNOW/MVFR.
TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MAINLY VFR DURING THE DAY THEN CHANCE OF -RASN AND
MVFR/IFR AT NIGHT.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF MVFR CIGS.
SATURDAY...CHANCE OF LIGHT SNOW/MVFR.
RATZER
&&
.MARINE...
137 AM CST
MAIN MARINE FORECAST FOCUS CONTINUES TO BE A PERIOD OF STRONG
NORTHEAST WINDS ACROSS THE SOUTHERN 2/3 OR SO OF LAKE MICHIGAN
THROUGH THIS EVENING.
A COLD FRONT HAS PUSHED SOUTH ACROSS MUCH OF LAKE MICHIGAN SINCE
SATURDAY MORNING...WITH COLD HIGH PRESSURE SPREADING ACROSS
MANITOBA...WESTERN ONTARIO AND THE NORTHERN LAKES. EARLY THIS
MORNING AN AREA OF LOW PRESSURE WAS OVER IOWA...AND THIS LOW WILL
MOVE QUICKLY SOUTHEAST TO THE LOWER OHIO VALLEY BY THIS EVENING.
THIS LOW AND THE HIGH PRESSURE TO THE NORTH OF THE LAKES WILL
COMBINE TO RAPIDLY TIGHTEN THE SURFACE PRESSURE GRADIENT ACROSS THE
LAKE THIS MORNING...WITH NORTH-NORTHEAST WINDS INCREASING TO 25-30
KT. RECENT OBSERVATION PLATFORMS ALONG THE WEST SHORE OF THE LAKE
HAVE BEEN GUSTING 26-27 KTS BEHIND THE COLD FRONT AS FAR SOUTH AS
MILWAUKEE. THESE STRONGER WINDS WILL CONTINUE TO DEVELOP SOUTHWARD
DOWN THE REMAINDER OF THE LAKE THIS MORNING. FORECAST SOUNDINGS
INDICATE WINDS TO 30 KT WILL BE PREVALENT THROUGH THE DAY...WITH A
FEW GALE FORCE GUSTS TO 35 KT POSSIBLE. WINDS WILL REMAIN GUSTY INTO
THE EVENING HOURS ACROSS THE FAR SOUTHERN PORTION OF THE LAKE...BUT
WILL DIMINISH RAPIDLY FROM THE NORTH AS A WEAK RIDGE OF HIGH
PRESSURE SPREADS IN BEHIND THE QUICK MOVING LOW WHICH MOVE TO THE
CAROLINA COAST BY MONDAY MORNING.
THE WEAK RIDGE WILL MOVE QUICKLY SOUTHEAST OF THE LAKE MONDAY...
WITH WINDS BRIEFLY BECOMING SOUTHERLY AND INCREASING BACK AROUND 20
KT OR SO AHEAD OF ANOTHER LOW PRESSURE SYSTEM WHICH WILL DROP
SOUTHEAST ACROSS THE LAKE MONDAY NIGHT...WHILE FILLING. WEAK
GRADIENT CONDITIONS WILL THEN LINGER ACROSS THE LAKE TUESDAY AND
TUESDAY NIGHT AS THE TROUGH FILLS AND A WEAK RIDGE MOVES ACROSS THE
REGION. INDICATIONS ARE THAT ANOTHER LOW WILL DEVELOP ACROSS THE
PLAINS MID-WEEK...AND WILL APPROACH THE LAKE FROM THE WEST LATE
WEDNESDAY. THIS MAY RESULT IN A BRIEF PERIOD OF ENHANCED
EAST-SOUTHEAST WINDS LATE WEDNESDAY OR WEDNESDAY NIGHT...WITH A
PERIOD OF GUSTY NORTHERLY WINDS POSSIBLE THURSDAY AS THE LOW MOVES
EAST OF THE LAKE.
FOR THE IL/NORTHWEST INDIANA NEARSHORE AREA...SMALL CRAFT ADVISORY
IS IN EFFECT FROM 6 AM CST THIS MORNING AS WINDS/WAVES QUICKLY
INCREASE AND BUILD. ADVISORY HEADLINE WILL REMAIN IN EFFECT THROUGH
MID-MORNING MONDAY...AS WAVES SLOWLY SUBSIDE BELOW 4 FT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-
LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 6 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 PM SUNDAY TO 9 AM MONDAY.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1128 AM CST Sun Jan 25 2015
.UPDATE...
ISSUED AT 1015 AM CST SUN JAN 25 2015
Surface low located just northwest of St. Louis late this morning.
Widespread precipitation continues over our northern CWA in the
deformation zone, with dual-pol radar data from showing the
rain/snow line roughly along a Canton to Lexington line, although
some mixed precipitation is showing up in the latest observation
from Champaign. Freezing level will continue to lower as the low
tracks toward Carbondale by midday, bringing the rain/snow line
closer to Springfield by early afternoon, where temperatures are
still currently in the lower 40s.
Will need to watch snow rates across the north closely. Already
have had 1 inch reported just northeast of Galesburg where light
to moderate snow continues. NOAA Satellite Analysis Branch shows
this area on the periphery of an area of enhanced snow production
over the next few hours, although drier air is being advected in
from the northeast where dew points in north central Illinois are
down to the low-mid 20s.
Have sent some updated zones/grids to update the precipitation and
transition trends, and to tweak the hourly temperatures especially
across the northern CWA.
&&
.SHORT TERM...(Today)
ISSUED AT 453 AM CST SUN JAN 25 2015
3am surface analysis has low pressure centered over southern Iowa
with the latest 3 hourly surface pressure falls suggesting a
continued southeast movement to the low this morning. Not a lot
of cold air associated with this particular storm system as surface
temperatures across Iowa, southern Minnesota and southeast South
Dakota were still above freezing after the low shifted away from
there area.
By 12z, the low is forecast by most models to be just west-southwest
of Quincy. Temperatures ahead of the low continue to slowly rise
early this morning with readings ranging from the mid 30s over far
eastern Illinois to the middle 40s over southwest Illinois. With the
low expected to push to near Lawrenceville by late this afternoon,
we expect the warmest temperatures across the north this morning
with steady or slowly falling temperatures this afternoon as winds
turn into the northeast and increase to between 15 and 25 mph with
gusts up to 30 mph at times.
The high resolution short term forecast soundings continue to show
temperatures at the surface too warm to support much in the way of
snow until later this morning across the north, and not until later
this afternoon over central through east central Illinois. Further
south, any changeover looks to hold off until the low shifts to
the south of the area this evening. Am a bit concerned with our
northern counties...roughly along and north of I-74...later this
morning and especially this afternoon when the low shifts further
to our southwest, surface winds up to 900 mb switch into the northeast
with soundings showing 30-40 kts around 900 mb. That may be enough
to bring surface temps down sufficiently for a brief period of time
for a period of moderate snowfall before soundings indicate we lose
the ice crystals in the upper layers of the clouds. However, except
for the NAM, which once again appears to have initialized too cold
in the lower levels of the atmosphere, all other forecast soundings
indicate surface temperatures should stay above freezing during the
daylight hours. Highest totals, in the 1 to 2 inch range will be
along and north of the I-74 corridor with lighter accumulations
to the south.
&&
.LONG TERM...(Tonight through Saturday)
ISSUED AT 453 AM CST SUN JAN 25 2015
Surface low pressure between Evansville and Louisville KY at sunset
and then into eastern KY by midnight tonight. Have increase chances
of mixed precipitation to likely over southeast IL during first half
of evening, as light rain changes to light snow before diminishing
during late evening. Snowfall amounts in southeast IL should be less
than a half inch. Gusty NNE winds linger during the evening before
diminishing overnight as low pressure pulls away from IL with weak
ridging into IL by dawn Monday. Lows tonight in the upper teens to
near 20F north and mid 20s south of I-70 in southeast IL.
Another clipper low pressure system will dive quickly southeast into
the upper MS river valley by sunset Monday, though this time best
chances of light snow to be NE of central IL Monday afternoon and
Monday night. Carried slight chances of light snow and flurries over
northern and NE counties Monday afternoon into Monday night. Highs
Monday range from lower 30s from Bloomington and Champaign NE to
near 40F from Jacksonville SW.
1025 mb surface high pressure drifts over IL Tue night and into the
eastern Ohio river valley Wed while upper level ridge noses into IL.
This to bring quiet weather with temps moderating again with highs
in the mid 30s to lower 40s Tue and 40s Wed and near 50F from
Jacksonville SW.
Low pressure off the Pacific northwest moves east into IL and Ohio
river valley Wed night and Thu returning a chance of mainly light
rain, though could be a mix of light snow northern counties before
ending. Highs Thu around 40F northern areas and mid 40s in southeast
IL. Cooler highs in the mid to upper 30s Friday which is close to
normal for late January. Extended models dig an upper level trof
over the Great Lakes and eastern states next weekend bringing
chances of light snow showers especially NE areas. Temps also cool
some more Sat night and Sunday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1128 AM CST SUN JAN 25 2015
Several challenges with this TAF set. Widespread precipitation
north of a KIJX-KDNV line has been changing from rain to snow.
Radar data indicates the transition line is just south of KBMI to
about 30SW KPIA, although a bit of mixed precipitation has also
been reported near KCMI. Still seeing temperatures in the upper
30s to lower 40s from KSPI-KCMI so the transition is still a
couple hours away. High-resolution model data suggests some
erosion in the precip shield as the afternoon goes on, as a
surface low travels through the southern tip of the state, so most
of the TAF sites should see the precip end by 00Z. Strong
northeast winds kicking in on the north flank of the low
circulation, so winds 25-30 knots will be spreading over the TAF
sites over the next couple hours and persist much of the evening.
IFR/LIFR conditions will be occurring as the snow moves through.
Some improvement expected this evening, but have largely kept MVFR
ceilings at all TAF sites through the night, as the wind flow does
not favor rapid clearing. Did scatter out KPIA for a time after
06Z, as suggested by a narrow clear slot on the RAP model. Winds
to turn more southwesterly Monday morning ahead of a storm system
which will pass to our north.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Smith
LONG TERM...07
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST SUN JAN 25 2015
.SHORT TERM...
329 AM CST
THROUGH TONIGHT...
HAVE FURTHERED THE DIMINISHING SNOWFALL TREND IN THE FORECAST FOR
TODAY...MAINLY NORTH OF INTERSTATE 80. ACROSS THE ENTIRE AREA THIS
LOOKS TO BE A MAINLY LOW IMPACT...NUISANCE TYPE SNOW...WITH SOME
COMMUNITIES IN THE NORTH QUITE POSSIBLY NOT SEEING ANY
ACCUMULATION. HAVE CONTINUED A SPECIAL WEATHER STATEMENT FOR AREAS
ALONG AND SOUTH OF I-80.
SATELLITE IMAGERY THIS MORNING DEPICTS THE CLOSED UPPER CIRCULATION
ACROSS WESTERN IA WITH AN AREA OF COOLING CLOUD TOPS IN ADVANCE OF
THIS MOVING INTO NORTHWEST IL. THIS IS CORRELATING WITH MAINLY LIGHT
RAIN OR RAIN/SNOW MIX IN THE SMALL WINDOW OF DEEPER MOIST
ADVECTION AHEAD OF THE LOW. SIMPLE EXTRAPOLATION OF THE CURRENT
AREA OF PRECIP IN IOWA AND THE DEVELOPING DEFORMATION ON THE
BACKSIDE CLEARLY INDICATE THE SOUTHERN CWA IS MORE SUPPORTED FOR
PRECIPITATION THAN THE NORTH. AT THE SURFACE...TEMPERATURES ARE
AROUND OR JUST ABOVE FREEZING ACROSS MUCH OF THE FORECAST AREA. A
DEVELOPING COLD FRONT IS ADVANCING SOUTHWARD INTO NORTHERN IL WITH
DEW POINTS IN THE MID TO UPPER 20S NORTH OF THIS FEATURE...ANOTHER
HINDRANCE OF APPRECIABLE PRECIPITATION IN NORTHERN AREAS OF THE
FORECAST AREA.
SHORT RANGE GUIDANCE LIKE ITS LONG RANGE COUNTERPARTS THE PAST
SEVERAL DAYS SHOW A FAIR AMOUNT OF DISCREPANCY...NAMELY ON COVERAGE
OF PRECIP TODAY AND PRECIP TYPE IN THE SOUTHERN CWA THIS
MORNING...BUT THEY LEND SUPPORT TO THE OBSERVATIONAL TRENDS. AS
THE AREA OF RAIN ASSOCIATED WITH ELEVATED ISENTROPIC ASCENT MOVES
INTO THE SOUTHERN FORECAST AREA...PROFILES SUPPORT A PERIOD OF
RAIN OR MIX INITIALLY...AND SOME LOCATIONS MIGHT HAVE AIR
TEMPERATURES RIGHT AT FREEZING. WOULD EXPECT ANY FREEZING RAIN
THREAT TO BE SHORT LIVED AS PROFILES TREND TOWARD SNOW. MESOSCALE
CONVERGENCE AND BAROCLINIC FORCING FOR INDUCED LIFT WOULD BECOME
MORE FAVORED JUST TO THE NORTHEAST OF THE CLOSED 850MB
CIRCULATION AS IT PIVOTS MORE EASTWARD. THAT IS FAVORED ACROSS
THE SOUTHERN TIER OR TWO OF COUNTIES LATER THIS MORNING INTO
EARLY AFTERNOON. PROFILES ARE MILD FOR IDEAL SNOW GROWTH...AND
MAYBE EVEN FOR SNOW AT ALL DOWN TOWARD GIBSON CITY FOR MUCH OF THE
MORNING. HAVE SNOW TOTALS AROUND ONE TO TWO INCHES FROM PERU TO
RENSSELAER AND SOUTHWARD FOR TODAY...WITH SNOW DEPARTING NEAR OR
SOON AFTER SUNDOWN.
AS FOR AREAS NORTH OF INTERSTATE 80...SHOULD SEE A GRADUAL INCREASE
IN LIGHT SNOW AREAWIDE BY MID-MORNING. DRY CORRIDOR NEAR 850MB
SEEN ON EARLY MORNING AMDAR SOUNDINGS OVER CHICAGO SHOULD LIMIT
INTENSITY OF ANY SNOW IN THE NORTHERN FORECAST AREA...AS WILL JUST
LESS FORCING. AREAS OF NORTHEAST ILLINOIS STILL LOOK TO HAVE
ONSHORE FLOW BEHIND THE COLD FRONT...BUT FORECAST INVERSION
HEIGHTS AS WELL AS ADAPTED ONES FROM THE 00Z GRB RAOB LAST
EVE...INDICATE VERY MARGINAL DEPTH OF CONVECTIVE CLOUDS. THUS NOT
EXPECTING MUCH IF ANY ENHANCEMENT TO ALREADY MINIMAL SYNOPTIC
FORCING OVER NORTHEAST IL. COULD SEE SOME DISORGANIZED LIGHT SNOW
OR FLURRIES LATE THIS AFTERNOON INTO THIS EVENING AS PROFILES OF
THE LAKE INDUCED STRATOCU COOL INTO THE ICE INITIATION LAYER...BUT
THIS SHOULD NOT BE A BIG DEAL.
AREAWIDE THE NORTHEAST WINDS WILL INCREASE TO 30 MPH AND MAYBE EVEN
A LITTLE HIGHER JUST OF THE LAKE. WITH MINIMAL SNOW NORTH NOT
EXPECTING ANY BLOWING SNOW ISSUES...AND SOUTH THE LOW SNOW-TO-
LIQUID RATIOS SHOULD SUPPRESS MUCH FOR BLOWING ISSUES...THOUGH
COULD LEAD TO MORE REDUCED VISIBILITY DURING THE TIME OF FALLING
SNOW THIS AFTERNOON.
MTF
&&
.LONG TERM...
329 AM CST
MONDAY THROUGH SATURDAY...
THE DISTURBED FLOW PATTERN WILL TURN MORE NORTHWESTERLY MONDAY AND
TUESDAY AS A MAJOR SYSTEM IS EXPECTED TO DEVELOP OFF THE NORTHEAST
COAST. GIVEN THIS POSSIBLY LEADING TO A SLOWER PATTERN...AS WELL
AS THE TREND OF TODAYS SYSTEM...IT IS QUITE CONCEIVABLE THAT THE
NEXT DISTURBANCE FOR MONDAY AFTERNOON AND NIGHT TRENDS WEST AS
WELL...WHICH THE EC HAS HAD IN ITS SOLUTION FOR THREE CONSECUTIVE
RUNS. THIS SYSTEM THOUGH IS NOT AS STRONG AS TODAYS AS IT IS MORE
OF A SHEARED AREA OF VORTICITY ALONG THE LINGERING BAROCLINIC
ZONE. FORCING FOR PRECIP LOOKS PRETTY LIGHT ONCE AGAIN MONDAY
AFTERNOON AND NIGHT BUT ENOUGH TO GO A LITTLE HIGHER ON POPS FOR
NORTHERN PARTS OF THE FORECAST AREA. RIGHT NOW GUIDANCE IS IN
DECENT AGREEMENT WITH SATURATING DEEP ENOUGH FOR PRECIP TYPE TO BE
LIGHT SNOW IF IT CAN OCCUR...BUT NEED TO KEEP AN EYE OUT FOR SOME
FREEZING DRIZZLE POTENTIAL IN THESE LIGHT ASCENT SITUATIONS.
A SLOW MODERATION LOOKS TO OCCUR TUESDAY INTO WEDNESDAY AND THIS
COULD BE VERY MINIMAL DEPENDING ON CLOUD COVER WHICH REMAINS A BIG
QUESTION MARK. HAVE LEANED MORE CLOUDY TUESDAY BUT STILL THINK
WITH A WESTERLY PUSH WEDNESDAY WOULD HAVE SUN POTENTIAL. LONG
RANGE GUIDANCE INDICATES A PACIFIC SYSTEM TO BE THE NEXT ONE TO
POSSIBLY BRING PRECIPITATION TO THE AREA WEDNESDAY NIGHT INTO
THURSDAY. CONTINUE POPS DURING THIS TIME FRAME AND AT THIS POINT
PROFILES ARE NEAR THE BORDER FOR RAIN OR SNOW...SO DID NOT GET TOO
FANCY WITH THE FORECAST PRECIPITATION TYPE. BEHIND THIS SYSTEM IT
SEEMS FAVORED FOR TEMPERATURES TO COOL SOME DURING THE LATTER
HALF OF THE WEEK...TO SLIGHTLY BELOW NORMAL VALUES. OBVIOUSLY ANY
FRESH SNOW COVER WOULD HELP LEAN THAT MORE TOWARD BELOW NORMAL.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* LIGHT SNOW THROUGH THIS AFTERNOON.
* IFR CIGS LIFTING TO MVFR BY THIS AFTERNOON...THEN SCATTERING OUT
TONIGHT.
* STRONG/GUSTY NORTHEAST WINDS THRU MID EVENING. CMS
//DISCUSSION...UPDATED 14Z...
LOW PRESSURE OVER NORTHEAST MISSOURI WILL MOVE ACROSS THE OHIO
VALLEY TONIGHT. NORTHEAST WINDS WILL REMAIN STRONG AND GUSTY THRU
THIS EVENING WITH GUSTS IN THE MID/UPPER 20KT RANGE. HEAVIEST
PRECIP SHOULD REMAIN ALONG AND SOUTH OF I-80 WITH LIGHTER AMOUNTS
NORTH. MANY AREAS REPORTING LIGHT SNOW BUT STILL SOME MIXED RAIN
AT MDW AND GYY...WHICH SHOULD TRANSITION TO SNOW BY LATE MORNING.
CMS
PREVIOUS 12Z DISCUSSION...
WEAK COLD FRONTAL BOUNDARY HAS SAGGED INTO NORTHEAST ILLINOIS
EARLY THIS MORNING...WITH IFR/LIFR CIGS NOTED IN THE VICINITY OF
THE FRONTAL BOUNDARY. EXPECT THE LIFR CIGS TO BE SOMEWHAT SHORT-
LIVED HOWEVER...AS WINDS RAMP UP FROM THE NORTHEAST.
RADAR CLEARLY SHOWS CIRCULATION WITH ALBERTA CLIPPER DROPPING
SOUTHEAST ACROSS IA...WITH EXPANSION OF WEAK RETURNS OVER NORTHERN
ILLINOIS AND A FEW REPORTS OF LIGHT SNOW BEGINNING TO REACH THE
GROUND. HIGH-RES HRRR HAS BEEN FAIRLY CONSISTENT IN BRINING NORTH
EDGE OF MORE ORGANIZED SNOW BAND ACROSS THE TERMINALS THIS MORNING
INTO MIDDAY/EARLY AFTERNOON...AND IS EXPECTED TO PRODUCE A PERIOD
OF LIGHT ACCUMULATING SNOW WITH OCCASIONAL IFR VSBYS. SNOW SHOULD
TAPER OFF TO LIGHT SNOW SHOWERS/FLURRIES THIS AFTERNOON WITH CIGS
RISING TO MVFR.
AS INDICATED ABOVE...STRONG/GUSTY NORTHEAST WINDS ARE ALREADY
RAMPING UP EARLY THIS MORNING WITH GUSTS 20-30 KT ALREAD ACROSS
FAR NORTHERN IL. 040-060 DEG WINDS NEAR 20 KT WITH GUSTS NEAR 30
KT ARE EXPECTED TO CONTIUNE INTO THE AFTERNOON BEFORE SLOW DECLINE
IN WIND SPEEDS AND A GRADUAL BACKING TO THE NORTH OCCURS. WINDS
WILL DIMINISH MORE QUICKLY TONIGHT...AS A WEAK HIGH PRESSURE RIDGE
BUILDS IN FROM THE NORTHWEST. THIS SHOULD ALLOW LOWER CLOUDS TO
SCATTER OUT OVERNIGHT.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH FOR LIGHT SNOW...MEDIUM FOR DURATION/END TIME THIS
AFTERNOON OR EARLY THIS EVENING.
* HIGH FOR CIGS THRU THIS AFTERNOON...THEN MEDIUM FOR THE REST OF
THE PERIOD.
* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...CHANCE LIGHT SNOW/MVFR.
TUESDAY...MVFR CIGS POSSIBLE.
WEDNESDAY...MAINLY VFR DURING THE DAY THEN CHANCE OF -RASN AND
MVFR/IFR AT NIGHT.
THURSDAY...CHANCE OF SNOW. MVFR/IFR POSSIBLE.
FRIDAY...CHANCE OF MVFR CIGS.
SATURDAY...CHANCE OF LIGHT SNOW/MVFR.
RATZER
&&
.MARINE...
137 AM CST
MAIN MARINE FORECAST FOCUS CONTINUES TO BE A PERIOD OF STRONG
NORTHEAST WINDS ACROSS THE SOUTHERN 2/3 OR SO OF LAKE MICHIGAN
THROUGH THIS EVENING.
A COLD FRONT HAS PUSHED SOUTH ACROSS MUCH OF LAKE MICHIGAN SINCE
SATURDAY MORNING...WITH COLD HIGH PRESSURE SPREADING ACROSS
MANITOBA...WESTERN ONTARIO AND THE NORTHERN LAKES. EARLY THIS
MORNING AN AREA OF LOW PRESSURE WAS OVER IOWA...AND THIS LOW WILL
MOVE QUICKLY SOUTHEAST TO THE LOWER OHIO VALLEY BY THIS EVENING.
THIS LOW AND THE HIGH PRESSURE TO THE NORTH OF THE LAKES WILL
COMBINE TO RAPIDLY TIGHTEN THE SURFACE PRESSURE GRADIENT ACROSS THE
LAKE THIS MORNING...WITH NORTH-NORTHEAST WINDS INCREASING TO 25-30
KT. RECENT OBSERVATION PLATFORMS ALONG THE WEST SHORE OF THE LAKE
HAVE BEEN GUSTING 26-27 KTS BEHIND THE COLD FRONT AS FAR SOUTH AS
MILWAUKEE. THESE STRONGER WINDS WILL CONTINUE TO DEVELOP SOUTHWARD
DOWN THE REMAINDER OF THE LAKE THIS MORNING. FORECAST SOUNDINGS
INDICATE WINDS TO 30 KT WILL BE PREVALENT THROUGH THE DAY...WITH A
FEW GALE FORCE GUSTS TO 35 KT POSSIBLE. WINDS WILL REMAIN GUSTY INTO
THE EVENING HOURS ACROSS THE FAR SOUTHERN PORTION OF THE LAKE...BUT
WILL DIMINISH RAPIDLY FROM THE NORTH AS A WEAK RIDGE OF HIGH
PRESSURE SPREADS IN BEHIND THE QUICK MOVING LOW WHICH MOVE TO THE
CAROLINA COAST BY MONDAY MORNING.
THE WEAK RIDGE WILL MOVE QUICKLY SOUTHEAST OF THE LAKE MONDAY...
WITH WINDS BRIEFLY BECOMING SOUTHERLY AND INCREASING BACK AROUND 20
KT OR SO AHEAD OF ANOTHER LOW PRESSURE SYSTEM WHICH WILL DROP
SOUTHEAST ACROSS THE LAKE MONDAY NIGHT...WHILE FILLING. WEAK
GRADIENT CONDITIONS WILL THEN LINGER ACROSS THE LAKE TUESDAY AND
TUESDAY NIGHT AS THE TROUGH FILLS AND A WEAK RIDGE MOVES ACROSS THE
REGION. INDICATIONS ARE THAT ANOTHER LOW WILL DEVELOP ACROSS THE
PLAINS MID-WEEK...AND WILL APPROACH THE LAKE FROM THE WEST LATE
WEDNESDAY. THIS MAY RESULT IN A BRIEF PERIOD OF ENHANCED
EAST-SOUTHEAST WINDS LATE WEDNESDAY OR WEDNESDAY NIGHT...WITH A
PERIOD OF GUSTY NORTHERLY WINDS POSSIBLE THURSDAY AS THE LOW MOVES
EAST OF THE LAKE.
FOR THE IL/NORTHWEST INDIANA NEARSHORE AREA...SMALL CRAFT ADVISORY
IS IN EFFECT FROM 6 AM CST THIS MORNING AS WINDS/WAVES QUICKLY
INCREASE AND BUILD. ADVISORY HEADLINE WILL REMAIN IN EFFECT THROUGH
MID-MORNING MONDAY...AS WAVES SLOWLY SUBSIDE BELOW 4 FT.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741-
LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872-
LMZ874-LMZ876-LMZ878 UNTIL 6 PM SUNDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...6 PM SUNDAY TO 9 AM MONDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
335 PM EST SUN JAN 25 2015
.SYNOPSIS...
ISSUED AT 331 PM EST SUN JAN 25 2015
A LOW PRESSURE SYSTEM MOVING SOUTH OF THE REGION WILL CONTINUE TO
BRING SNOW TO THE FORECAST AREA THROUGH LATE TONIGHT. WINDS
GUSTING UP TO 30 MPH WILL CAUSE SNOW TO BLOW AND
DRIFT...ESPECIALLY IN THE SOUTHEAST. OTHERWISE...LOW TEMPERATURES
WILL DROP INTO THE SINGLE DIGITS AND TEENS TONIGHT. MONDAY WILL BE
QUIET...WITH PARTLY TO MOSTLY CLOUDY SKIES AND HIGHS IN THE 20S.
&&
.UPDATE...
ISSUED AT 106 PM EST SUN JAN 25 2015
HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW.
EXPECT SNOWFALL AMOUNTS OF 2 TO 5 INCHES COMBINED WITH BLOWING AND
DRIFTING SNOW. MUCH COLDER AIR WAS SPREADING ACROSS THE AREA FROM
THE NORTHEAST. SUSTAINED WINDS HAD INCREASED BEHIND THE FRONT TO
AROUND 20 MPH WITH SOME GUSTS OVER 30 MPH. THE LATEST NCEP HI/RES
SUPPORT BASICALLY 2 TO 5 INCHES OF SNOW OVER AREAS EAST AND SOUTH
OF FT WAYNE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EST SUN JAN 25 2015
CHALLENGING SHORT TERM FORECAST AS PCPN TYPE IN QUESTION EARLY TODAY
AND SNOWFALL AMOUNTS WILL DEPEND ON TIMING OF CHANGEOVER TO ALL
SNOW. 00Z MODELS GENERALLY IN GOOD AGREEMENT SYNOPTICALLY WITH
ALMOST ALL SOLUTIONS TAKING SURFACE LOW SOUTHEAST FROM IA THIS
MORNING TO NEAR KEVV BY EARLY AFTERNOON...THEN EAST ACROSS NORTHERN
KENTUCKY TONIGHT. PRECIPITATION WILL SPREAD EAST ACROSS THE LOCAL
AREA TODAY AHEAD AND NORTH OF THE LOW.
STRONG MERIDIONAL JET DIVING SOUTH THROUGH THE PLAINS WILL DRIVE
CLIPPER SYSTEM SOUTHEAST TODAY. LOW LEVEL NORTHEAST FLOW WILL
INCREASE AND THIS WILL BRING COLDER AIR SOUTH HELPING ERODE WARM
LAYER ALOFT AND CHANGE PCPN OVER TO ALL SNOW FROM NORTH TO SOUTH.
THERE IS A BIT OF A CONCERN THOUGH AS MOST HIRES GUIDANCE HAS BEEN
ANYWHERE FROM 2 TO 5 DEGREES TOO WARM WITH SFC TEMPS EARLY THIS
MORNING ACROSS LOWER MICHIGAN. AS OF 08Z THOUGH WE ARE FINALLY
STARTING TO SEE A THERMAL RESPONSE IN SFC OBS WITH TEMPS DROPPING A
FEW DEGREES. THIS IS ENCOURAGING BUT STILL CONCERNED THAT MODELS ARE
A FEW HOURS TOO FAST BRINGING THE COLDER AIR SOUTH WHICH IN TURN
COULD DELAY CHANGEOVER IN FAR SOUTH UNTIL MID AFTERNOON.
HRRR...RUC AND LAMP GUIDANCE HAVE BEEN PLAYING CATCHUP ALL NIGHT.
HAVE MANUALLY ADJUSTED HOURLY SFC TEMPS WITH SLIGHTLY SLOWER COOLING
THAN RUC GUIDANCE SUGGESTS. DO EXPECT COLDER AIR TO QUICKLY MOVE SOUTH
ONCE CLIPPER GETS CLOSER AND PRESSURE GRADIENT TIGHTENS LATER THIS
MORNING.
MEANWHILE...LACK OF LOW CLOUDS ALONG WITH LIGHT WINDS IN THE WESTERN
CWA HAS ALLOWED SFC TEMPS THERE TO DROP TO AROUND FREEZING WITH SOME
FOG DEVELOPMENT. DO EXPECT TEMPS HERE TO RISE ABOVE FREEZING AHEAD
OF PCPN ARRIVAL WITH SFC TEMPS ACROSS CENTRAL ILLINOIS IN THE MID TO
UPPER 30S EARLY THIS MORNING. THIS COMBINED WITH 1000-850MB WARM
TONGUE OF 2 TO 4C DEPICTED BY HIRES GUIDANCE SUGGEST A MIX OF RAIN
AND SNOW UNTIL WARM LAYER IS FULLY ERODED. TOP DOWN METHOD ACTUALLY
DEPICTS A FEW HOURS OF JUST RAIN ACROSS THE EXTREME SOUTHERN CWA
LATE MORNING INTO EARLY AFTERNOON BEFORE FULLY CHANGING OVER TO
SNOW.
THE FARTHER SOUTH TRACK OF CLIPPER HAS ALSO MEANT A SOUTHWARD SHIFT
IN STRONGEST FORCING AND HEAVIEST PCPN AXIS. STRONGEST FGEN FORCING
AND BANDING POTENTIAL NOW LOOKS TO BE JUST SOUTH OF OUR AREA. THIS
COMBINED WITH MIXED PCPN AND DELAYED CHANGEOVER TO SNOW HAS LED TO
DECREASED SNOW AMOUNTS OVER THE ENTIRE AREA. MODEL QPF NOW GENERALLY
AROUND A QUARTER INCH SOUTH OF THE US24 CORRIDOR. MIXING RATIOS OF 3
TO 4 G/KG AND PWATS AROUND 0.5 INCHES STILL A CONCERN...ESPECIALLY
IF ANY BANDING DEVELOPS. STILL EXPECT A SWATH OF 2 TO 4 INCHES
ACROSS THE FAR SOUTH AND THE HIGHER END AMOUNTS SOUTHEAST WHERE
PIVOT POINT AND SNOW THIS EVENING TAKE ADVANTAGE OF SLIGHTLY BETTER
RATIOS. ISOLATED AMOUNTS OF 5 INCHES NOT OUT OF QUESTION IF BANDING
CLIPS THIS AREA. WITH THIS BEING MID WINTER AND EXPECTATION OF A WET
2 TO 4 INCHES WITH LOW IMPACTS FOR TRAVEL HAVE OPTED TO NOT ISSUE
ANY ADVISORY AT THIS TIME. WILL HIGHLIGHT SNOWFALL IN AN SPS AND
HWO.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 439 AM EST SUN JAN 25 2015
NEXT CLIPPER-TYPE SYSTEM TO POTENTIALLY IMPACT THE AREA WILL ARRIVE
ON MONDAY NIGHT. FORCING MECHANISM IS REALLY MORE ACCURATELY
DESCRIBED AS JUST A THIN RIBBON OF CYCLONIC SHEAR VORTICITY ON THE
UPWIND SIDE OF DEEPENING EAST COAST TROUGH. AS SUCH...FORCING FOR
ASCENT IS PRETTY MINUSCULE AND RESIDENT AIRMASS...AT LEAST IN THE
MIDLEVELS...IS VERY DRY. WEAK 285K ISENTROPIC ASCENT AND SUBTLE LOW
LEVEL MOISTURE ADVECTION MAY GENERATE SOME VERY LIGHT SNOW BUT
LITTLE TO NO ACCUMULATION IS EXPECTED. PREFERENCE STILL LIES WITH
THE DRIER/FURTHER SOUTHWEST CANADIAN AND EUROPEAN SOLUTIONS.
ACTUALLY AM A LITTLE CONCERNED ABOUT POTENTIAL FOR FREEZING DRIZZLE.
NAM AND GFS FORECAST SOUNDINGS INDICATE DEEP ENOUGH SATURATION TO
SUPPORT ICE NUCLEATION BUT JUST BARELY AND AM CONCERNED THEY ARE
OVERDOING THE EXTENT OF LOW LEVEL MOISTURE AND ASCENT. WILL HOLD OFF
ON INCLUDING IN THE FORECAST FOR NOW GIVEN THE HIGHER PROBABILITY
THAT ANY PRECIPITATION THAT DOES MANAGE TO OCCUR WILL DO SO IN AN
ENVIRONMENT ADEQUATELY SATURATED TO SUPPORT ICE NUCLEI AND OTHER
LOCATIONS WILL SIMPLY REMAIN DRY. SOMETHING TO KEEP AN EYE ON THOUGH.
MORE IMPRESSIVE WAVE IS SET TO PLOW OVER THE WEST COAST RIDGE ON
WEDNESDAY. THIS ACTUALLY FORCES DOWNSTREAM HEIGHT RISES LOCALLY WITH
A BRIEF RETURN TO SOUTHWEST FLOW AND WARMER TEMPERATURES. SHORTWAVE
WILL THEN ENTER OUR REGION ON THURSDAY WITH THE NEXT DECENT CHANCE
OF PRECIP. NEEDLESS TO SAY....FORECAST CONFIDENCE IN EXACT TRACK IS
LOW AND THIS WILL HAVE A LARGE IMPACT ON THERMAL PROFILES AND QPF
TOTALS. CURRENTLY APPEARS THE BEST CHANCE FOR SIGNIFICANT SNOW WILL
REMAIN OVER CENTRAL MICHIGAN WITH MORE OF A MIX ACROSS NORTHERN
INDIANA AND OHIO. THIS WILL UNDOUBTEDLY CHANGE AS WE GET CLOSER
THOUGH.
AFTER A COLD START ON MONDAY...TEMPERATURES WILL QUICKLY RETURN TO
VALUES AT OR ABOVE NORMAL FOR THE MIDWEEK PERIOD. COOLER TEMPS
EXPECTED AFTER THURSDAY`S WAVE BUT MUCH COLDER CONDITIONS STILL
APPEAR POSSIBLE EARLY NEXT WEEK AFTER A THIRD WAVE/ARCTIC FRONT
PASSES OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 106 PM EST SUN JAN 25 2015
THE PRECIPITATION HAS BECOME ALL SNOW AT BOTH TERMINALS WITH
STRONG COLD AIR ADVECTION FROM THE NORTHEAST. HAVE ADDED THE
MENTION OF BLOWING SNOW AT FT WAYNE WITH STRONGER WINDS EXPECTED.
OTHERWISE...HAVE MADE SOME MINOR ADJUSTMENTS TO THE TIMING OF THE
SNOW AND THE IMPROVEMENT TO VFR CONDITIONS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR INZ026-
027-032>034.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR OHZ015-
016-024-025.
LM...NONE.
&&
$$
UPDATE...SKIPPER
SYNOPSIS...MCD
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...SKIPPER
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
132 PM EST SUN JAN 25 2015
.SYNOPSIS...
ISSUED AT 430 AM EST SUN JAN 25 2015
AN AREA OF LOW PRESSURE WILL MOVE FROM SOUTHERN IOWA THIS MORNING
TO SOUTHWEST INDIANA BY MID AFTERNOON AND THEN THROUGH KENTUCKY
TONIGHT. THIS CLIPPER SYSTEM WILL SPREAD ACCUMULATING SNOW OVER
PARTS OF NORTH CENTRAL AND NORTHERN INDIANA AND NORTHWEST OHIO
TODAY WITH RAIN SOUTH OF THIS AREA. HIGH TEMPERATURES WILL
OCCUR THIS MORNING WITH READINGS RANGING FROM THE LOWER 20S NORTH
TO UPPER 30S SOUTH. EXPECT FALLING TEMPERATURES DURING THE DAY.
LOWS TONIGHT WILL BE VERY COLD WITH SINGLE DIGITS ACROSS THE NORTH
AND TEENS SOUTH.
&&
.UPDATE...
ISSUED AT 106 PM EST SUN JAN 25 2015
HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW.
EXPECT SNOWFALL AMOUNTS OF 2 TO 5 INCHES COMBINED WITH BLOWING AND
DRIFTING SNOW. MUCH COLDER AIR WAS SPREADING ACROSS THE AREA FROM
THE NORTHEAST. SUSTAINED WINDS HAD INCREASED BEHIND THE FRONT TO
AROUND 20 MPH WITH SOME GUSTS OVER 30 MPH. THE LATEST NCEP HI/RES
SUPPORT BASICALLY 2 TO 5 INCHES OF SNOW OVER AREAS EAST AND SOUTH
OF FT WAYNE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 439 AM EST SUN JAN 25 2015
CHALLENGING SHORT TERM FORECAST AS PCPN TYPE IN QUESTION EARLY TODAY
AND SNOWFALL AMOUNTS WILL DEPEND ON TIMING OF CHANGEOVER TO ALL
SNOW. 00Z MODELS GENERALLY IN GOOD AGREEMENT SYNOPTICALLY WITH
ALMOST ALL SOLUTIONS TAKING SURFACE LOW SOUTHEAST FROM IA THIS
MORNING TO NEAR KEVV BY EARLY AFTERNOON...THEN EAST ACROSS NORTHERN
KENTUCKY TONIGHT. PRECIPITATION WILL SPREAD EAST ACROSS THE LOCAL
AREA TODAY AHEAD AND NORTH OF THE LOW.
STRONG MERIDIONAL JET DIVING SOUTH THROUGH THE PLAINS WILL DRIVE
CLIPPER SYSTEM SOUTHEAST TODAY. LOW LEVEL NORTHEAST FLOW WILL
INCREASE AND THIS WILL BRING COLDER AIR SOUTH HELPING ERODE WARM
LAYER ALOFT AND CHANGE PCPN OVER TO ALL SNOW FROM NORTH TO SOUTH.
THERE IS A BIT OF A CONCERN THOUGH AS MOST HIRES GUIDANCE HAS BEEN
ANYWHERE FROM 2 TO 5 DEGREES TOO WARM WITH SFC TEMPS EARLY THIS
MORNING ACROSS LOWER MICHIGAN. AS OF 08Z THOUGH WE ARE FINALLY
STARTING TO SEE A THERMAL RESPONSE IN SFC OBS WITH TEMPS DROPPING A
FEW DEGREES. THIS IS ENCOURAGING BUT STILL CONCERNED THAT MODELS ARE
A FEW HOURS TOO FAST BRINGING THE COLDER AIR SOUTH WHICH IN TURN
COULD DELAY CHANGEOVER IN FAR SOUTH UNTIL MID AFTERNOON.
HRRR...RUC AND LAMP GUIDANCE HAVE BEEN PLAYING CATCHUP ALL NIGHT.
HAVE MANUALLY ADJUSTED HOURLY SFC TEMPS WITH SLIGHTLY SLOWER COOLING
THAN RUC GUIDANCE SUGGESTS. DO EXPECT COLDER AIR TO QUICKLY MOVE SOUTH
ONCE CLIPPER GETS CLOSER AND PRESSURE GRADIENT TIGHTENS LATER THIS
MORNING.
MEANWHILE...LACK OF LOW CLOUDS ALONG WITH LIGHT WINDS IN THE WESTERN
CWA HAS ALLOWED SFC TEMPS THERE TO DROP TO AROUND FREEZING WITH SOME
FOG DEVELOPMENT. DO EXPECT TEMPS HERE TO RISE ABOVE FREEZING AHEAD
OF PCPN ARRIVAL WITH SFC TEMPS ACROSS CENTRAL ILLINOIS IN THE MID TO
UPPER 30S EARLY THIS MORNING. THIS COMBINED WITH 1000-850MB WARM
TONGUE OF 2 TO 4C DEPICTED BY HIRES GUIDANCE SUGGEST A MIX OF RAIN
AND SNOW UNTIL WARM LAYER IS FULLY ERODED. TOP DOWN METHOD ACTUALLY
DEPICTS A FEW HOURS OF JUST RAIN ACROSS THE EXTREME SOUTHERN CWA
LATE MORNING INTO EARLY AFTERNOON BEFORE FULLY CHANGING OVER TO
SNOW.
THE FARTHER SOUTH TRACK OF CLIPPER HAS ALSO MEANT A SOUTHWARD SHIFT
IN STRONGEST FORCING AND HEAVIEST PCPN AXIS. STRONGEST FGEN FORCING
AND BANDING POTENTIAL NOW LOOKS TO BE JUST SOUTH OF OUR AREA. THIS
COMBINED WITH MIXED PCPN AND DELAYED CHANGEOVER TO SNOW HAS LED TO
DECREASED SNOW AMOUNTS OVER THE ENTIRE AREA. MODEL QPF NOW GENERALLY
AROUND A QUARTER INCH SOUTH OF THE US24 CORRIDOR. MIXING RATIOS OF 3
TO 4 G/KG AND PWATS AROUND 0.5 INCHES STILL A CONCERN...ESPECIALLY
IF ANY BANDING DEVELOPS. STILL EXPECT A SWATH OF 2 TO 4 INCHES
ACROSS THE FAR SOUTH AND THE HIGHER END AMOUNTS SOUTHEAST WHERE
PIVOT POINT AND SNOW THIS EVENING TAKE ADVANTAGE OF SLIGHTLY BETTER
RATIOS. ISOLATED AMOUNTS OF 5 INCHES NOT OUT OF QUESTION IF BANDING
CLIPS THIS AREA. WITH THIS BEING MID WINTER AND EXPECTATION OF A WET
2 TO 4 INCHES WITH LOW IMPACTS FOR TRAVEL HAVE OPTED TO NOT ISSUE
ANY ADVISORY AT THIS TIME. WILL HIGHLIGHT SNOWFALL IN AN SPS AND
HWO.
&&
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 439 AM EST SUN JAN 25 2015
NEXT CLIPPER-TYPE SYSTEM TO POTENTIALLY IMPACT THE AREA WILL ARRIVE
ON MONDAY NIGHT. FORCING MECHANISM IS REALLY MORE ACCURATELY
DESCRIBED AS JUST A THIN RIBBON OF CYCLONIC SHEAR VORTICITY ON THE
UPWIND SIDE OF DEEPENING EAST COAST TROUGH. AS SUCH...FORCING FOR
ASCENT IS PRETTY MINUSCULE AND RESIDENT AIRMASS...AT LEAST IN THE
MIDLEVELS...IS VERY DRY. WEAK 285K ISENTROPIC ASCENT AND SUBTLE LOW
LEVEL MOISTURE ADVECTION MAY GENERATE SOME VERY LIGHT SNOW BUT
LITTLE TO NO ACCUMULATION IS EXPECTED. PREFERENCE STILL LIES WITH
THE DRIER/FURTHER SOUTHWEST CANADIAN AND EUROPEAN SOLUTIONS.
ACTUALLY AM A LITTLE CONCERNED ABOUT POTENTIAL FOR FREEZING DRIZZLE.
NAM AND GFS FORECAST SOUNDINGS INDICATE DEEP ENOUGH SATURATION TO
SUPPORT ICE NUCLEATION BUT JUST BARELY AND AM CONCERNED THEY ARE
OVERDOING THE EXTENT OF LOW LEVEL MOISTURE AND ASCENT. WILL HOLD OFF
ON INCLUDING IN THE FORECAST FOR NOW GIVEN THE HIGHER PROBABILITY
THAT ANY PRECIPITATION THAT DOES MANAGE TO OCCUR WILL DO SO IN AN
ENVIRONMENT ADEQUATELY SATURATED TO SUPPORT ICE NUCLEI AND OTHER
LOCATIONS WILL SIMPLY REMAIN DRY. SOMETHING TO KEEP AN EYE ON THOUGH.
MORE IMPRESSIVE WAVE IS SET TO PLOW OVER THE WEST COAST RIDGE ON
WEDNESDAY. THIS ACTUALLY FORCES DOWNSTREAM HEIGHT RISES LOCALLY WITH
A BRIEF RETURN TO SOUTHWEST FLOW AND WARMER TEMPERATURES. SHORTWAVE
WILL THEN ENTER OUR REGION ON THURSDAY WITH THE NEXT DECENT CHANCE
OF PRECIP. NEEDLESS TO SAY....FORECAST CONFIDENCE IN EXACT TRACK IS
LOW AND THIS WILL HAVE A LARGE IMPACT ON THERMAL PROFILES AND QPF
TOTALS. CURRENTLY APPEARS THE BEST CHANCE FOR SIGNIFICANT SNOW WILL
REMAIN OVER CENTRAL MICHIGAN WITH MORE OF A MIX ACROSS NORTHERN
INDIANA AND OHIO. THIS WILL UNDOUBTEDLY CHANGE AS WE GET CLOSER
THOUGH.
AFTER A COLD START ON MONDAY...TEMPERATURES WILL QUICKLY RETURN TO
VALUES AT OR ABOVE NORMAL FOR THE MIDWEEK PERIOD. COOLER TEMPS
EXPECTED AFTER THURSDAY`S WAVE BUT MUCH COLDER CONDITIONS STILL
APPEAR POSSIBLE EARLY NEXT WEEK AFTER A THIRD WAVE/ARCTIC FRONT
PASSES OVER THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 106 PM EST SUN JAN 25 2015
THE PRECIPITATION HAS BECOME ALL SNOW AT BOTH TERMINALS WITH
STRONG COLD AIR ADVECTION FROM THE NORTHEAST. HAVE ADDED THE
MENTION OF BLOWING SNOW AT FT WAYNE WITH STRONGER WINDS EXPECTED.
OTHERWISE...HAVE MADE SOME MINOR ADJUSTMENTS TO THE TIMING OF THE
SNOW AND THE IMPROVEMENT TO VFR CONDITIONS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR INZ026-
027-032>034.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR OHZ015-
016-024-025.
LM...NONE.
&&
$$
UPDATE...SKIPPER
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...SKIPPER
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AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1113 AM CST SUN JAN 25 2015
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CST SUN JAN 25 2015
A 500 MILLIBAR SHORTWAVE TROUGH WAS MOVING SOUTHEAST OVER THE
CENTRAL PLAINS EARLY THIS MORNING. AT THE SURFACE, AN ASSOCIATED LOW
PRESSURE SYSTEM WAS ALSO TRACKING SOUTHEAST OVER SOUTHERN IOWA. THE
UPPER WAVE WAS MOVING INTO OKLAHOMA EARLY THIS MORNING AS LIGHT
PRECIPITATION THAT WAS OVER THE AREA EARLIER IN THE NIGHT HAD MOVED
INTO EASTERN OKLAHOMA AND CLOUDS WERE DIMINISHING OVER WESTERN
KANSAS.
FAIRLY STRONG WINDS ALOFT WERE ALSO MOVING SOUTHEAST OVER THE AREA
IN THE WAKE OF THE SHORTWAVE. THE KDDC VWP WAS SHOWING 50-55 KNOT
WINDS OFF THE SURFACE WHICH IS IN GOOD AGREEMENT WITH 850 MILLIBAR
WIND PROGS FROM THE RUC13 AND HRRR. THESE MODELS SHOW A BROAD AREA
OF 50-60 KNOT WINDS OVER SOUTHWEST KANSAS EARLY THIS MORNING WHICH
MAKES SENSE GIVEN THE NUMEROUS REPORTS OF 25-30 KNOT WINDS REPORTS
FROM AREA AWOS`S. THE MODELS SHOW THE AREA OF STRONGER WINDS GRADUALLY
PROPAGATING SOUTHWARD INTO OKLAHOMA BY MID/LATE MORNING. WE SHOULD
SEE THE STRONG WINDS CONTINUING THROUGH MUCH OF THE DAY. THERE COULD
BE A SMALL WINDOW OF OPPORTUNITY FOR 50+ KNOT WIND GUSTS AROUND
MEDICINE LODGE LATER THIS MORNING BUT THE STRONGEST WINDS SHOULD
BE SOUTH OF SOUTHWEST KANSAS BY THE TIME THE BOUNDARY LAYER BEGINS
TO MIX OUT. WINDS IN THE LOWER ATMOSPHERE WILL GRADUALLY WEAKEN DURING
THE AFTERNOON HOURS. WE SHOULD SEE WINDS DROP OFF FAIRLY QUICKLY TOWARD
SUNSET AS THE BOUNDARY LAYER DECOUPLES.
THE MODELS ARE SHOWING A COOLER DAY FOR SOUTHWEST KANSAS THAN WAS
PREVIOUSLY THOUGHT. 850 MILLIBAR TEMPERATURES THIS AFTERNOON WILL BE
COOLER THAN SATURDAY BY SOME 4-8 DEGREES CELSIUS. THIS WILL TRANSLATE
TO HIGHS RANGING FROM AROUND 50 AT HAYS TO THE MID/UPPER 50S FROM
DODGE CITY WEST TO THE COLORADO LINE. SURFACE WINDS TONIGHT WILL
GRADUALLY SWITCH TO THE WEST AND COULD INCREASE AGAIN TO AROUND
10-12 KNOTS. THIS COULD KEEP LOW TEMPERATURES HELD UP IN THE LOWER
TO MIDDLE 30S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 308 AM CST SUN JAN 25 2015
UPPER LEVEL RIDGING WILL PERSIST OVER THE ROCKIES MONDAY AND
TUESDAY BEFORE A SHORTWAVE TROUGH FLATTENS OUT THE RIDGE ON
WEDNESDAY AND PROGRESSES ACROSS THE PLAINS. THIS ENTIRE PERIOD
WILL BE CHARACTERIZED BY WARM TEMPERATURES WITH VARYING WIND
DIRECTIONS FROM DAY TO DAY IN RESPONSE TO SUBTLE CHANGES IN THE
SURFACE PRESSURE FIELD. HIGHS OUGHT TO REACH INTO THE UPPER 60S TO
LOWER 70S. A COLD FRONT WILL PASS ACROSS WESTERN KANSAS WEDNESDAY
AFTERNOON IN THE WAKE OF THIS SHORTWAVE TROUGH, WITH COOLER
TEMPERATURES RETURNING FOR WEDNESDAY NIGHT THROUGH THE REMAINDER
OF THE WEEK AS SURFACE HIGH PRESSURE BUILDS IN.
THERE IS A LOT OF UNCERTAINTY IN THE FORECAST AFTER FRIDAY AS THE
VARIOUS MODELS ARE EXHIBITING LOTS OF VARIABILITY WITH RESPECT TO
THE AMPLITUDE OF AN UPPER LEVEL LOW OVER BAJA. COLD AIR CONTINUES
TO BE DELIVERED INTO THE MIDWEST AND GREAT LAKES REGIONS. IF THE
SOUTHWESTERN SYSTEM PROGRESSES FAR ENOUGH EAST AND INTERACTS WITH
THE WESTERN AND SOUTHERN EDGE OF THE COLD DOME, THEN SNOW WOULD BE
POSSIBLE. THE OVERALL TREND IN THE MODELS OVER THE PAST FEW RUNS
HAS BEEN FOR A STRONGER SYSTEM OVER THE DESERT SOUTHWEST AND BAJA.
BUT IT IS VERY UNCERTAIN JUST HOW FAR NORTHEAST ANY PRECIPITATION
WOULD OCCUR AND JUST HOW COLD IT WILL BE OVER WESTERN KANSAS. FOR
NOW, THERE IS FAIRLY HIGH CONFIDENCE IN A CHANGE TO COOLER OR COLDER
TEMPERATURES FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1111 AM CST SUN JAN 25 2015
VFR CONDITIONS EXPECTED THROUGH TAF PD AS DRY ATMOSPHERE CONTINUES.
NORTHWESTERLY WINDS 22-30 KT WITH DECREASE NNW 8-12 KT BY 00Z. WINDS
WILL INCREASE WNW/NW AGAIN 10-20 KT BY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 56 34 70 35 / 0 0 0 0
GCK 57 34 71 35 / 0 0 0 0
EHA 55 37 69 35 / 0 0 0 0
LBL 57 33 69 35 / 0 0 0 0
HYS 50 31 70 36 / 0 0 0 0
P28 54 31 70 37 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GERARD
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
325 PM EST SUN JAN 25 2015
.SYNOPSIS...
LOW PRESSURE WILL BRING WIDESPREAD SNOW LATER TODAY THROUGH
MONDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
LATEST WV IMAGERY SHOWS MID LEVEL LOW CENTER JUST OVER WESTERN KY
NOW SHIFTING EAST AS THE ASSOCIATED JET MAX SITS RIGHT OVER OR
EAST OF THE TROUGH AXIS. THE HRRR HAS BEEN HANDLING THINGS WELL SO
FAR TODAY AND OPTED TO MAKE MINOR CHANGES TO AMOUNTS AND LOCATIONS
OF MORE INTENSE SNOW THIS EVENING BASED ON LATEST RUNS.
OVERALL...VERY LITTLE CHANGE WAS NEEDED TO THE PREVIOUS FORECAST
AS LATEST RUNS HELD GOOD CONTINUITY. TEMPERATURES IN THE LOWER
LEVELS ARE SLIGHTLY WARMER SOUTH OF INTERSTATE 70 AND
CONSEQUENTLY THE CHANGEOVER TO SNOW MAY NOT BE UNTIL WELL AFTER
MIDNIGHT...SO AMOUNTS MAY NOT BE QUITE AS HIGH ACROSS THE SOUTHERN
FRINGE OF THE FORECAST AREA. TO THE NORTH WHERE PRECIPITATION WILL
BE ALL SNOW...ACCUMULATIONS ARE STILL EXPECTED TO RANGE FROM 4-6
INCHES THROUGH MONDAY WITH THE GREATEST AMOUNTS FROM PITTSBURGH
NORTH TO INTERSTATE 80 WHERE MODELS SHOW THE BEST DYNAMICS. THE
MOST INTENSE SNOWFALL RATES AREA EXPECTED TO OCCUR FROM EARLY THIS
EVENING UNTIL SHORTLY AFTER MIDNIGHT. THE WINTER WEATHER ADVISORY
WHICH COVERS THE ENTIRE FORECAST AREA WAS LEFT UNCHANGED. SNOW
WILL CONTINUE THROUGH MUCH OF MONDAY AS MOISTURE WRAPS AROUND THE
LOW AND ASSOCIATED INVERTED TROUGH SHIFTS NORTHEAST OVER THE REGION.;
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
UNSETTLED CONDITIONS WILL CONTINUE UNTIL HIGH PRESSURE BUILDS IN
BY WEDNESDAY MORNING. UNTIL THEN...SCATTERED SNOW SHOWERS WILL
PERSIST UNDER NORTHWESTERLY FLOW ALOFT AND A SUFFICIENTLY
DEEP BOUNDARY LAYER. TEMPERATURES WILL FALL TO APPROXIMATELY 10
DEGREES BELOW CLIMO NORMALS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
WEDNESDAY AND WEDNESDAY NIGHT MAY BE THE ONLY DRY 24 HOUR PERIOD
FOR THE ENTIRE FORECAST AREA THROUGH THE SEVEN DAY FORECAST. HIGH
PRESSURE WILL MOVE ACROSS THE REGION ON WEDNESDAY...AND SHOULD
ALLOW FOR ONE PARTLY/MOSTLY SUNNY DAY.
FAST MOVING CLIPPER SYSTEM WILL BRING ANOTHER ROUND OF SNOW
THURSDAY INTO THURSDAY NIGHT WITH A WINTRY MIX POSSIBLE ALONG AND
SOUTH OF I-70. BUMPED UP POPS TO LIKELY FOR THIS SYSTEM. UPPER
LEVEL TROUGH WILL REMAIN IN PLACE INTO NEXT WEEKEND WITH WELL
BELOW NORMAL TEMPERATURES. SOME IMPORTANT TIMING DIFFERENCES FOR
NEXT WEEKEND WITH NEXT CLIPPER AND DELIVERY OF EVEN COLDER ARCTIC
AIR INTO THE UPPER OHO VALLEY. WPC PROGS LOOKS TO BE A GOOD
COMPROMISE WITH A CHANCE OF SNOW SHOWERS LATER SATURDAY THROUGH
SUNDAY.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
THERE ARE A MIX OF MVFR/IFR CIGS IN ADVANCE OF THE LOW PRESSURE
SYSTEM THAT WILL MOVE INTO THE REGION THIS AFTERNOON/EVENING. AS
WIDESPREAD SNOW ARRIVES...ALL SITES WILL BECOME IFR AND EVENTUALLY
LIFR. FKL/DUJ ARE THE ONLY SITES THAT MAY NOT DROP TO LIFR IF
HEAVIER SNOW REMAINS TO THE SOUTH. ALSO EXPECT ZZV/MGW TO HAVE A
MIX OF RAIN/SNOW BEFORE CHANGING TO ALL SNOW. INTERMITTENT VLIFR
IN HEAVIER SNOW BANDS IS ALSO POSSIBLE...BUT DO NOT HAVE
CONFIDENCE FOR TIMING/LOCATION TO INCLUDE IN 18Z TAFS. SNOW WILL
CONTINUE...BUT IS EXPECTED TO EASE UP IN INTENSITY...BY MONDAY
MORNING.
.OUTLOOK.../MONDAY THROUGH FRIDAY/...
RESTRICTIONS IN SNOW WILL CONTINUE MONDAY AFTERNOON INTO TUESDAY.
NEXT WIDESPREAD RESTRICTIONS THURSDAY AFTERNOON INTO FRIDAY WITH A
CLIPPER SYSTEM.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR MDZ001.
OH...WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR OHZ039>041-
048>050-057>059-068-069.
PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR PAZ007>009-
013>016-020>023-029-031-073>076.
WV...WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR WVZ001>004-
012-021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
245 PM EST SUN JAN 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EST SUN JAN 25 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
DOMINTING THE GREAT LKS BTWN HI AMPLITUDE RDG ALONG THE W COAST AND
A DEEP UPR TROF IN ERN NAMERICA CENTERED OVER NRN QUEBEC. SFC HI
PRES UNDER THIS NW FLOW IS BLDG SE THRU NW ONTARIO...WITH A COLD NNE
FLOW ON ITS SRN FLANK ADVECTING H85 TEMPS AS LO AS -15C OVER LK SUP
EARLY THIS MRNG. THE INFUSION OF THIS VERY COLD AIR OVER THE
RELATIVELY WARM LK SUP WATERS IS RESULTING IN SOME LK EFFECT SN
SHOWERS ACROSS MAINLY NCENTRAL UPR MI...WHERE THE LLVL FLOW IS
PRESENTING A MORE SGNFT UPSLOPE WIND COMPONENT. DESPITE FVRBL SN
GROWTH MICROPHYSICS WITH THE DGZ WITHIN MUCH OF THE CONVECTIVE
LYR...HI STABILITY/DRYNESS OF INCOMING AIRMASS PER THE 00Z YPL
RAOB...WHERE THE 00Z PWAT WAS ONLY 0.05 INCH AND THE SUBSIDENCE
INVRN WAS LOCATED NEAR H9 /MQT VWP INDICATES THE INVRN BASE HERE IS
NEAR 3K FT AGL/...AS WELL AS THE LARGER SCALE ACYC FLOW THAT IS
MINIMIZING LLVL CNVGC IS TENDING TO LIMIT THE INTENSITY OF THE LES.
OVER THE E...SKIES HAVE BEGUN TO CLEAR AT NEWBERRY WITH MINIMAL
OVERWATER TRAJECTORY AND SOME DOWNSLOPING OF THE LLVL NE FLOW OFF
ONTARIO...WHERE SFC DEWPTS EARLY THIS MRNG ARE AS LO AS -20 TO -25F
TO THE N OF LK SUP. LOOKING FARTHER UPSTREAM...A FAIRLY STRONG
SHRTWV IS MOVING THRU WRN CANADA OVER TOP THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE LES TRENDS ASSOCIATED WITH
THE COLD NE LLVL FLOW THAT WL PERSIST INTO THIS AFTN. FOCUS FOR TNGT
SHIFTS TO LO TEMPS AND SN CHCS LATE OVER THE W ASSOCIATED WITH
DISTURBANCE NOW TRACKING THRU WRN CANADA.
TODAY...SFC HI PRES CENTER IS FCST TO DRIFT SLOWLY TO THE SE OVER
FAR NE LK SUP BY 00Z MON. LLVL NE FLOW WL PERSIST THRU THIS
MRNG...BUT THEN WEAKEN AS THE HI CENTER MOVES CLOSER AND SFC RDG
AXIS EXTENDING TO THE SW MOVES OVHD BY 00Z. WITH THE -15C H85
ISOTHERM OVER CENTRAL LK SUP AND THE DGZ IN THE 1-3K FT LYR
ENCOMPASSING MUCH OF THE CONVECTIVE LYR...SOME FLUFFY LES WL PERSIST
IN THE NE SN BELTS OVER MAINLY THE NCENTRAL. DESPITE THE PRESENCE OF
THE DGZ AND SUFFICIENT CHILL OF THE AIRMASS...INVRN BASE NEAR 3K FT
AGL AND ACYC NATURE OF THE H925 FLOW WL CONTINUE TO LIMIT ADDITIONAL
SN ACCUMS TO AN INCH OR LESS. DURING THE AFTN WHEN THE WINDS/UPSLOPE
FORCING DIMINISH FURTHER AND THE SFC RDG AXIS BECOMES MORE
PRONOUNCED...THE LES SHOULD TEND TO DIMINISH EVEN FURTHER. THE ERN
CWA SHOULD BE MOSUNNY WITH DOWNSLOPE FLOW/MINIMAL OVERWATER
TRAJECTORY OF THE DRY AIRMASS. NEAR THE WI BORDER...SOME BREAKS IN
THE SC OVC ARE LIKELY BY MID/LATE AFTN WITH THE CLOSER APRCH OF THE
SFC RDG AXIS. BUT EVEN WHERE THE SUN COMES OUT...HI TEMPS WL BE HARD
PRESSED TO RISE OUT OF THE TEENS PER OBSVD HI TEMPS IN ONTARIO YDAY.
TNGT...AS THE SFC RDG AXIS SHIFTS TO THE E AND THE SHRTWV NOW OVER
WRN CANADA DIGS THRU SCENTRAL CANADA TOWARD THE UPR LKS...THE LLVL
FLOW WL TURN TO THE SSW. FCST SDNGS INDICATE ANY LINGERING LO CLDS
WL DSPT OR SHIFT OUT INTO LK SUP AND GIVE WAY TO A PERIOD OF MOCLR
CONDITIONS BEFORE CLDS ASSOCIATED WITH ISENTROPIC ASCENT AHEAD OF
THE APRCHG CLIPPER SHRTWV INVADE THE AREA NW TO SE. COMBINATION OF
EARLIER ARRIVING CLDS/STRENGTHENING SSW WIND WL TEND TO LIMIT THE
DIURNAL TEMP FALL OVER THE W. BUT OVER THE E...EXPECT TEMPS TO FALL
TOWARD THE LO END OF GUIDANCE BEFORE THE LATER ARRIVAL OF HI CLDS
AND STRENGTHENING FLOW OFF LK MI TENDS TO STOP THE TEMP FALL. THE
BULK OF THE MODELS ARE STILL HINTING THE LEADING EDGE OF THE WAA SN
WL REACH THE WRN CWA BY 12Z MON...SO RETAINED SOME CHC POPS THERE
LATE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 244 PM EST SUN JAN 25 2015
NAM SHOWS A DEEP 500 MB TROUGH OVER THE EASTERN U.S. WITH A STRONG
RIDGE OVER THE ROCKIES 00Z TUE. THIS RIDGE WEAKENS AS IT MOVES INTO
THE PLAINS ON TUE. NAM...GFS AND ECMWF SHOW 850-500 MB Q-VECTOR
CONVERGENCE MOVING INTO UPPER MICHIGAN ON WED.
WILL CONTINUE WITH CHANCE POPS FOR MON NIGHT AS A WEAK SYSTEM MOVES
THROUGH. THE MOISTURE FROM THIS SYSTEM DEPARTS ON TUE AND SHOULD BE
DRY FOR TUE NIGHT. ON WED...POPS WILL SLOWLY MOVE SOUTH ACROSS THE
CWA WITH CHANCE POPS ACROSS THE NORTHERN CWA BY LATE WED AFTERNOON.
DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST OVERALL.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB TROUGH OVER THE UPPER
GREAT LAKES 12Z THU WITH AN ALBERTA CLIPPER SYSTEM TO THE SOUTH OF
THE AREA. THIS CLIPPER WILL BRING IN SOME COLDER AIR ON FRI WITH
MORE UPPER TROUGHING FOR SAT WITH ANOTHER CLIPPER MOVING THROUGH THE
AREA. THIS CLIPPER HELPS TO CARVE OUT A BROAD AND DEEP 500 MB TROUGH
OVER THE EASTERN U.S. ON SUN. TEMPERATURES WILL FALL AND STAY BELOW
NORMAL FOR THIS FORECAST PERIOD. HAVE CHANCE POPS FOR WED NIGHT WITH
PASSAGE OF AN ALBERTA CLIPPER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1248 PM EST SUN JAN 25 2015
WEAKENING NORTHEASTERLY FLOW FROM A HIGH NEAR THUNDER BAY WILL LEAD
TO GRADUALLY DIMINISHING LAKE EFFECT CLOUDS AND SNOW SHOWERS AT
KCMX/KSAW THIS AFTERNOON AND EARLY EVENING. EXPECT THEIR CONDITIONS
TO BE PRIMARILY MVFR UNTIL THE HIGH SHIFTS EAST AND WINDS INCREASE
OUT OF THE SOUTH...LEADING TO CEILINGS RISING TO VFR. AT
KIWD...THEY HAVE SCATTERED OUT OVER THE LAST HOUR...BUT SATELLITE
AND WEBCAMS INDICATE BROKEN CLOUDS JUST UP STREAM. THUS...HAVE
STUCK WITH A MORE PESSIMISTIC MVFR CEILING TO START THE PERIOD
BEFORE ALSO TRENDING TO VFR.
A CLIPPER SYSTEM CURRENTLY OVER THE CANADIAN ROCKIES WILL QUICKLY
DROP SOUTHEAST ACROSS THE AREA LATE TONIGHT AND MONDAY. THIS WILL
LEAD TO GRADUALLY LOWERING CEILINGS AHEAD OF THE SYSTEM AND THEN SNOW
MOVING IN AT KIWD LATE TONIGHT AND KCMX/KSAW TOMORROW MORNING. THE
IFR VISIBILITIES WILL AFFECT KIWD LATE TONIGHT AND THEN KCMX TOWARDS
MID MORNING. HAVE HELD OFF ON LOWERING VISIBILITIES BELOW MVFR AT
KSAW DUE TO THE LATE ARRIVAL AND EXPECTED WEAKENING OF THE SNOW
HEADING INTO THE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 352 AM EST SUN JAN 25 2015
N TO NE WINDS UP TO 20-25 KTS THIS MORNING WILL DIMINISH THIS
AFTERNOON WITH ARRIVAL OF A HI PRES RIDGE. AS THE HI SHIFTS TO THE E
AND A LO PRES APPROACHES FROM THE NW TONIGHT AND MON...EXPECT
INCREASING S WINDS UP TO 25-30 KTS ON MON...STRONGEST OVER THE E
HALF OF THE LAKE. WINDS WILL THEN DIMINISH TO UNDER 20 KTS ON TUE
AND TUE NIGHT AS THE WEAKENING LO SLIDES TO THE SE AND A TRAILING HI
PRES RIDGE MOVES THRU THE UPPER LAKES. LIGHT S WINDS IN THE WAKE OF
THE DEPARTING HI ON WED WILL GIVE WAY STRENGTHENING N WINDS UP TO 25-
30 KTS ON THU FOLLOWING THE PASSAGE OF A LO PRES THRU THE LOWER
LAKES. THE ARRIVAL OF MUCH COLDER AIR AND INCREASING WAVES WILL
LIKELY RESULT IN SOME HEAVY FREEZING SPRAY BY LATE THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...07
AVIATION...SRF
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1249 PM EST SUN JAN 25 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM EST SUN JAN 25 2015
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT
DOMINTING THE GREAT LKS BTWN HI AMPLITUDE RDG ALONG THE W COAST AND
A DEEP UPR TROF IN ERN NAMERICA CENTERED OVER NRN QUEBEC. SFC HI
PRES UNDER THIS NW FLOW IS BLDG SE THRU NW ONTARIO...WITH A COLD NNE
FLOW ON ITS SRN FLANK ADVECTING H85 TEMPS AS LO AS -15C OVER LK SUP
EARLY THIS MRNG. THE INFUSION OF THIS VERY COLD AIR OVER THE
RELATIVELY WARM LK SUP WATERS IS RESULTING IN SOME LK EFFECT SN
SHOWERS ACROSS MAINLY NCENTRAL UPR MI...WHERE THE LLVL FLOW IS
PRESENTING A MORE SGNFT UPSLOPE WIND COMPONENT. DESPITE FVRBL SN
GROWTH MICROPHYSICS WITH THE DGZ WITHIN MUCH OF THE CONVECTIVE
LYR...HI STABILITY/DRYNESS OF INCOMING AIRMASS PER THE 00Z YPL
RAOB...WHERE THE 00Z PWAT WAS ONLY 0.05 INCH AND THE SUBSIDENCE
INVRN WAS LOCATED NEAR H9 /MQT VWP INDICATES THE INVRN BASE HERE IS
NEAR 3K FT AGL/...AS WELL AS THE LARGER SCALE ACYC FLOW THAT IS
MINIMIZING LLVL CNVGC IS TENDING TO LIMIT THE INTENSITY OF THE LES.
OVER THE E...SKIES HAVE BEGUN TO CLEAR AT NEWBERRY WITH MINIMAL
OVERWATER TRAJECTORY AND SOME DOWNSLOPING OF THE LLVL NE FLOW OFF
ONTARIO...WHERE SFC DEWPTS EARLY THIS MRNG ARE AS LO AS -20 TO -25F
TO THE N OF LK SUP. LOOKING FARTHER UPSTREAM...A FAIRLY STRONG
SHRTWV IS MOVING THRU WRN CANADA OVER TOP THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE LES TRENDS ASSOCIATED WITH
THE COLD NE LLVL FLOW THAT WL PERSIST INTO THIS AFTN. FOCUS FOR TNGT
SHIFTS TO LO TEMPS AND SN CHCS LATE OVER THE W ASSOCIATED WITH
DISTURBANCE NOW TRACKING THRU WRN CANADA.
TODAY...SFC HI PRES CENTER IS FCST TO DRIFT SLOWLY TO THE SE OVER
FAR NE LK SUP BY 00Z MON. LLVL NE FLOW WL PERSIST THRU THIS
MRNG...BUT THEN WEAKEN AS THE HI CENTER MOVES CLOSER AND SFC RDG
AXIS EXTENDING TO THE SW MOVES OVHD BY 00Z. WITH THE -15C H85
ISOTHERM OVER CENTRAL LK SUP AND THE DGZ IN THE 1-3K FT LYR
ENCOMPASSING MUCH OF THE CONVECTIVE LYR...SOME FLUFFY LES WL PERSIST
IN THE NE SN BELTS OVER MAINLY THE NCENTRAL. DESPITE THE PRESENCE OF
THE DGZ AND SUFFICIENT CHILL OF THE AIRMASS...INVRN BASE NEAR 3K FT
AGL AND ACYC NATURE OF THE H925 FLOW WL CONTINUE TO LIMIT ADDITIONAL
SN ACCUMS TO AN INCH OR LESS. DURING THE AFTN WHEN THE WINDS/UPSLOPE
FORCING DIMINISH FURTHER AND THE SFC RDG AXIS BECOMES MORE
PRONOUNCED...THE LES SHOULD TEND TO DIMINISH EVEN FURTHER. THE ERN
CWA SHOULD BE MOSUNNY WITH DOWNSLOPE FLOW/MINIMAL OVERWATER
TRAJECTORY OF THE DRY AIRMASS. NEAR THE WI BORDER...SOME BREAKS IN
THE SC OVC ARE LIKELY BY MID/LATE AFTN WITH THE CLOSER APRCH OF THE
SFC RDG AXIS. BUT EVEN WHERE THE SUN COMES OUT...HI TEMPS WL BE HARD
PRESSED TO RISE OUT OF THE TEENS PER OBSVD HI TEMPS IN ONTARIO YDAY.
TNGT...AS THE SFC RDG AXIS SHIFTS TO THE E AND THE SHRTWV NOW OVER
WRN CANADA DIGS THRU SCENTRAL CANADA TOWARD THE UPR LKS...THE LLVL
FLOW WL TURN TO THE SSW. FCST SDNGS INDICATE ANY LINGERING LO CLDS
WL DSPT OR SHIFT OUT INTO LK SUP AND GIVE WAY TO A PERIOD OF MOCLR
CONDITIONS BEFORE CLDS ASSOCIATED WITH ISENTROPIC ASCENT AHEAD OF
THE APRCHG CLIPPER SHRTWV INVADE THE AREA NW TO SE. COMBINATION OF
EARLIER ARRIVING CLDS/STRENGTHENING SSW WIND WL TEND TO LIMIT THE
DIURNAL TEMP FALL OVER THE W. BUT OVER THE E...EXPECT TEMPS TO FALL
TOWARD THE LO END OF GUIDANCE BEFORE THE LATER ARRIVAL OF HI CLDS
AND STRENGTHENING FLOW OFF LK MI TENDS TO STOP THE TEMP FALL. THE
BULK OF THE MODELS ARE STILL HINTING THE LEADING EDGE OF THE WAA SN
WL REACH THE WRN CWA BY 12Z MON...SO RETAINED SOME CHC POPS THERE
LATE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 340 AM EST SUN JAN 25 2015
EXPECT NO SIGNIFICANT PATTERN CHANGES THROUGH THE PERIOD...AS A
500MB TROUGH LINGERS ACROSS EASTERN CANADA AND MUCH OF THE EAST HALF
OF THE U.S. THE MAIN EXCEPTION WILL BE TUESDAY THROUGH WEDNESDAY AS
THE RIDGE ACROSS THE WEST MOVES ACROSS THE PLAINS AND GREAT LAKES
REGION. BY 00Z THURSDAY 850MB TEMPS SHOULD WARM TO -4 TO -1C
/WARMEST OFF THE 24/12Z ECMWF/. SFC TEMPS TOPPING OUT NEAR FREEZING
WILL BE THE RESULT WEDNESDAY AFTERNOON. THE WARM SPELL WILL BE SHORT
LIVED AS COLDER AIR SET UP OVER N CENTRAL CANADA SHIFTS SINKS ACROSS
HUDSON BAY ON FRIDAY...AND SURGE ACROSS ONTARIO AND INTO THE UPPER
GREAT LAKES FROM SATURDAY THROUGH THE START OF THE NEXT WORK WEEK.
THE EXACT TIMING...SATURDAY OR LATER SATURDAY NIGHT...IS STILL IN
QUESTION. THE 25/00Z IS A LITTLE SLOWER TO PUSH THE COLD AIR DOWN.
GIVEN THAT THIS IS OVER 150HRS OUT...WILL GO WITH A BLENDED SOLUTION
FOR NOW.
AS FOR SOME OF THE SPECIFICS...WE WILL START 12Z MONDAY WITH THE
NEXT LOW KNOCKING ON THE DOOR /SET UP ACROSS SE MANITOBA THROUGH N
MN/. THE CANADIAN AND ECMWF ARE ON THE SW END OF THE LOW TRACK
ENVELOPE...WHILE THE NAM AND GFS ARE FARTHER TO THE NE AND TRACK IT
OVER W LAKE SUPERIR BY 00Z TUESDAY. EITHER WAY THE ROUGHLY 150 MILE
DIFFERNECE IN PLACMENT OF THE LOW DOES MAKE A DIFFERENCE IN THE WIND
FIELDS...BUT BOTH INDICATE SNOW FOR WESTERN AND AT LEAST MOST OF
CENTRAL UPPER MI. THIS SW TREND IN THE BETTER FORCING OCCURRED WITH
THE LAST SIGNIFICANT CLIPPER SYSTEM TOO...SO WE WILL SEE IF THIS
CONTINUES. WILL KEEP THE LIKELY POPS IN THE W ONLY.
BEHIND THE LOW A SFC RIDGE WILL SLIDE ACROSS UPPER MI FROM THE
W...AS THE NEXT LOW ORGANIZES ACROSS THE PLAINS STATES
TUESDAY/WEDNESAY. EXPECT THIS LOW /EXTENDING FROM ND ALL THE WAY
THROUGH N TX AT 18Z WEDNESDAY TO PUSH ACROSS FAR S LAKE MI BY
DAYBREAK THURSDAY. THERE IS AMAZING CONSISTANCY WITH THE TRACK AND
STRENGTH OF THIS LOW FOR THIS 108HR FCST. THE INVERTED TROUGH WILL
EXTEND ALL THE WAY THROUGH N LAKE SUPERIOR 00-12Z THURSDAY. THIS
WILL BE THE FOCUS FOR SNOW...ASSISTED BY THE NEXT ELONGATED
SHORTWAVE SWINGING IN FROM THE NW. AT THIS POINT THE GFS IS HINTING
IN 3-5IN OF SNOW FROM 00Z THURSDAY THROUGH 00Z FRIDAY...BEFORE THE
INVERSION HEIGHTS START DROPPING BELOW 5KFT AS STRONG HIGH PRESSURE
BEGINS TO BUILD IN FROM THE NW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1248 PM EST SUN JAN 25 2015
WEAKENING NORTHEASTERLY FLOW FROM A HIGH NEAR THUNDER BAY WILL LEAD
TO GRADUALLY DIMINISHING LAKE EFFECT CLOUDS AND SNOW SHOWERS AT
KCMX/KSAW THIS AFTERNOON AND EARLY EVENING. EXPECT THEIR CONDITIONS
TO BE PRIMARILY MVFR UNTIL THE HIGH SHIFTS EAST AND WINDS INCREASE
OUT OF THE SOUTH...LEADING TO CEILINGS RISING TO VFR. AT
KIWD...THEY HAVE SCATTERED OUT OVER THE LAST HOUR...BUT SATELLITE
AND WEBCAMS INDICATE BROKEN CLOUDS JUST UP STREAM. THUS...HAVE
STUCK WITH A MORE PESSIMISTIC MVFR CEILING TO START THE PERIOD
BEFORE ALSO TRENDING TO VFR.
A CLIPPER SYSTEM CURRENTLY OVER THE CANADIAN ROCKIES WILL QUICKLY
DROP SOUTHEAST ACROSS THE AREA LATE TONIGHT AND MONDAY. THIS WILL
LEAD TO GRADUALLY LOWERING CEILINGS AHEAD OF THE SYSTEM AND THEN SNOW
MOVING IN AT KIWD LATE TONIGHT AND KCMX/KSAW TOMORROW MORNING. THE
IFR VISIBILITIES WILL AFFECT KIWD LATE TONIGHT AND THEN KCMX TOWARDS
MID MORNING. HAVE HELD OFF ON LOWERING VISIBILITIES BELOW MVFR AT
KSAW DUE TO THE LATE ARRIVAL AND EXPECTED WEAKENING OF THE SNOW
HEADING INTO THE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 352 AM EST SUN JAN 25 2015
N TO NE WINDS UP TO 20-25 KTS THIS MORNING WILL DIMINISH THIS
AFTERNOON WITH ARRIVAL OF A HI PRES RIDGE. AS THE HI SHIFTS TO THE E
AND A LO PRES APPROACHES FROM THE NW TONIGHT AND MON...EXPECT
INCREASING S WINDS UP TO 25-30 KTS ON MON...STRONGEST OVER THE E
HALF OF THE LAKE. WINDS WILL THEN DIMINISH TO UNDER 20 KTS ON TUE
AND TUE NIGHT AS THE WEAKENING LO SLIDES TO THE SE AND A TRAILING HI
PRES RIDGE MOVES THRU THE UPPER LAKES. LIGHT S WINDS IN THE WAKE OF
THE DEPARTING HI ON WED WILL GIVE WAY STRENGTHENING N WINDS UP TO 25-
30 KTS ON THU FOLLOWING THE PASSAGE OF A LO PRES THRU THE LOWER
LAKES. THE ARRIVAL OF MUCH COLDER AIR AND INCREASING WAVES WILL
LIKELY RESULT IN SOME HEAVY FREEZING SPRAY BY LATE THU.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...SRF
MARINE...KC
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
344 PM CST Sun Jan 25 2015
.SHORT TERM: (Through Late Tonight)
Issued at 323 PM CST Sun Jan 25 2015
Precip over the CWA should be winding down over the next few hours
as upper level impulse works its way SE into the Ohio Valley.
Deformation zone that was so well defined this morning over IA and
n IL certainly falling apart as the afternoon progresses, and have
used a combination of regional radar and HRRR for PoP/weather
trends heading into the early evening. It would appear that the NW
edge of the precip (now all snow) will be near a KCOU-KILX line
by 00z, with the precip dropping southeast and exiting
SE sections of the CWA no later than 06z. Surface obs trends this
afternoon indicate that rain begins mixing with snow @ 36-37 and
is all snow at 34 or colder, and will use this for ptypes for the
rest of the afternoon and into the early evening. Given warm
ground and the light intensity of the precip once it goes to all
snow, accumulations should continue to be very minor.
Other question for tonight is how much clearing will occur as the
storm exits and a narrow ridge of high pressure works into the
region. Over the last few hours have seen a wedge of clearing
wrapping around the surface low from S WI into NE IA. Some of this
clearing may reach our area, but there is also a lot of additional
low cloud to our north that will advect our way as well, so for
now have only gone with partial clearing during the late evening
and overnight hours.
Truett
.LONG TERM: (Monday through Next Sunday)
Issued at 323 PM CST Sun Jan 25 2015
(Monday-Wednesday)
Overall, going forecast heading into midweek still looks pretty
good, so this package will include generally minor adjustments and
tweaks to these trends.
Fast moving shortwave in northwest flow will zip into the region on
Monday, with WAA in advance of this feature rapidly shutting down
the CAA occuring overnight in the wake of today`s clipper. 12z
synoptic runs are suggesting a fairly strong N-S warm front will be
located near or just west of STL by late Monday afternoon and have
attempted to reflect this in max temp forecast, allowing highs to
rebound into the middle 50s over mid MO while keeping highs in the
30s over our S IL counties. This temp trend also seems to be
supported by the model RH progs which suggest a fairly thick mid
deck sweeping from W to E across the area in the zone of WAA during
the day, with the most clouds over our eastern counties during the
afternoon. Some 12z guidance is even trying to kick out some
light QPF near and east of the Mississippi River in the zone of
strongest WAA. Have continued dry forecast for now, but will need
to keep an eye on this as there has been some very subtle suggestions
of this for several days.
The cold air advection behind Monday`s shortwave will try to dip
into the area Monday night, but with the longwave trof working into
the east coast during this time the main thrust of this cooler air
will be east of our area. Model consensus of thermal profiles over
the region support highs in the 40s over most of the CWA by Tuesday
as weak surface ridge drops into the Mississippi Valley.
Warmup still appears to be on schedule for Wednesday, and main
question is how much of the warming will be able to translate to the
surface. Forecast soundings are suggesting a large inversion, with
low level mixing up to 900-950mb. Surface/low level winds...while
strong...are going to primarily be southerly rather than the
southwest direction that normally gives us our biggest warmups.
Also some doubt to how much cloud cover there will be, as GFS
suggests some mid clouds working into the area during the afternoon
while NAM suggests lots of sunshine. Due to the above uncertainty
will keep highs about where they are now...ranging from the mid 40s
in our far eastern counties to near 60 in the far western tip of our
CWA.
(Thursday-Sunday)
Shortwave that works across the region Wednesday night and early
Thursday appears to be the first of several chunks of energy that
will be deepening long wave trof over the eastern U.S. heading into
the weekend, while cutoff low forms over the southwestern U.S.
Medium range solutions are in very broad agreement in developing
this split flow pattern, and in general this should mean temps
trending back towards more wintry levels after the mid-week warmup.
Will continue some slight chance PoPs on Wednesday night/Thursday
for eastern parts of the FA in advance of aforementioned shortwave,
with slight chance PoPs also continuing for parts of the FA on
Saturday and Saturday night as there is agreement in the medium
range models that WAA, a bit of shortwave energy, and a frontal
boundary will be passing through the area at that time.
Guidance is in reasonable agreement with their thermal profiles
through Saturday, but much like yesterday the operational ECMWF
continues to be deepest with the upper trof and much colder than the
GFS by the end of the period (it`s intesting to note that last
nights ECMWF-based MOS had over a 40 degree difference between the
warm and cold members for Sunday`s highs (58 vs 16). For now, will
lean towards MOS averages for temp trends on Sunday...which will be
in the 30s. This seems to be a reasonable compromise at this point,
with additional adjustments occurring as specific trends become less
muddled.
Truett
&&
.AVIATION: (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1142 AM CST Sun Jan 25 2015
Low pressure centered just to the east-southeast of St. Louis will
continue moving east-southeast through tonight. Light rain falling
across much of the area will continue into the afternoon, changing
to light snow before ending early this evening. MVFR conditions
south of the I-70 corridor are expected to fall to IFR this
afternoon. IFR flight conditions are expected to continue to
prevail at least into the early evening, with improving ceilings
and visibilities as the precipitation comes to and end and the low
moves further east. Some guidance suggests that the low clouds
will scatter out overnight, however am siding with more pessimistic
models at this time as there is a lot of MVFR and even IFR up
across the Dakotas, Iowa, Minnesota, and Wisconsin. One other
feature of note, wind will be increasing substantially later this
afternoon as the low pulls away. Expect north-northwest wind
sustained between 15 to 20 kts with gusts potentially up to 30 kts.
Specifics for KSTL:
Expect IFR ceilings and at times IFR visibilities in light
rain/drizzle this afternoon. Wind will increase to the northwest
later sustained between 15 and 20 kts with gusts between 25 and
30 kts. Still expecting a little snow late this afternoon or early
this evening. Confidence in the exact timing of the snow is not
especially high though. Did not want to change the current 23Z
transition time for the 18Z TAF because of this, but an hour on
either side of 23Z still seems like the most likely. Snow should
end quickly this evening with ceilings between 1000-2000 FT
persisting through Monday morning.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1150 AM CST SUN JAN 25 2015
.DISCUSSION...
UPPER SHORTWAVE MOVING TOWARD THE MID STATE THIS AFTERNOON. AS
THE SFC LOW AND FRONTAL BOUNDARY DESCENDS UPON THE MID STATE...WAA
OUT AHEAD OF THE BOUNDARY IS PUSHING TEMPS UPWARD AND THEY ARE
ALREADY APPROACHING MAX TEMPS FOR TODAY...WEST OF PLATEAU. WILL
THEREFORE ELECT TO RAISE MAX TEMPS A FEW DEGREES.
OTHERWISE...RADAR SHOWING LEADING EDGE OF THE RAIN SHOWER ACTIVITY
NOW INTO OUR WESTERNMOST COUNTIES. HRRR CONCURS WITH THIS BUT DEF
POPS WILL NEED TO BE TRIMMED BACK TO LIKELY FOR OUR CENTRAL AREAS.
THE TIMING APPEARS TO BE A LITTLE SLOWER. BUT...CERTAINLY BY
00Z...THE DEEPER MOISTURE WILL BE UPON US.
NO OTHER CHANGES NEEDED...STILL SEEING SOME GUSTS...PARTICULARLY
OUTAHEAD OF THE LEADING EDGE OF PRECIP WHERE MORE IN THE WAY OF
SUBSIDENCE EXISTS.
UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 1136 AM CST SUN JAN 25 2015/
AVIATION 18Z DISCUSSION...
UPPER LEVEL SHORTWAVE TO MOVE ACROSS KY DURING THE TAF PD. THIS
WILL PRODUCE RAIN SHOWER ACTIVITY ACROSS THE MID STATE BEGINNING
A LITTLE LATER THIS AFTERNOON AND CONTINUING INTO TONIGHT. OF
FURTHER CONSEQUENCE...FREEZING LEVELS WILL DROP TO SUFFICIENT SNOW
LEVELS AND WE WILL SEE THE TAIL END OF THE PRECIPITATION SWITCH TO
SNOW BETWEEN 08Z AND 12Z. THE LIGHT SNOW WILL
CONTINUE...ESPECIALLY NEAR CSV...FROM 12Z THRU 16Z.
AS FOR CIGS AND VSBYS...IFR LEVEL CIGS ARE EXPECTED TO BEGIN
BETWEEN 21Z AND 00Z. THE LOW CIGS WILL CONT THRU THE TAF PD.
VSBYS NOT LOOKING TOO BAD. REDUCTIONS DUE TO SNOWFALL SHOULD
MINIMAL GIVEN THE EXPECTED LIGHT NATURE OF THE SNOW.
PREV DISCUSSION... /ISSUED 548 AM CST SUN JAN 25 2015/
UPDATE...FOR 12Z AVIATION FORECASTS.
AVIATION...A FAST-MOVING LOW PRESSURE AREA WILL PUSH INTO EXTREME
SOUTHERN ILLINOIS BY 18Z, BRINGING MVFR CONDITIONS TO CKV BY 17Z
AND TO BNA BY 19Z. AS THE LOW PUSHES SOUTHEASTWARD INTO KENTUCKY
DURING THE AFTERNOON, EXPECT MVFR CONDITIONS TO DEVELOP AT CSV BY
22Z. CONDITIONS WILL DETERIORATE TO IFR AT ALL TERMINALS LATE THIS
AFTERNOON AND EVENING, WITH LIFR AT CSV BY 02Z. SFC WINDS WILL
BECOME GUSTY AND SWITCH FROM SOUTH, TO WEST, TO NORTHWEST, AS THE
LOW PRESSURE AREA PASSES ACROSS KENTUCKY LATER TODAY AND TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 54 33 39 32 / 70 60 20 10
CLARKSVILLE 53 30 40 32 / 90 70 10 10
CROSSVILLE 50 32 37 28 / 30 80 50 20
COLUMBIA 54 33 41 32 / 70 60 10 10
LAWRENCEBURG 55 33 41 32 / 60 60 10 10
WAVERLY 53 32 41 31 / 90 60 10 05
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1124 AM CST SUN JAN 25 2015
.AVIATION...
GENERALLY CLEAR SKY EXPECTED WITH ONLY HIGH CLOUDS FORESEEN. SURFACE
WINDS ARE NOW BEING FORECAST TO BE OF LESSER SPEEDS THAN PREVIOUSLY
THOUGHT...DUE TO DETERIORATION OF SURFACE PRESSURE GRADIENT CURRENTLY
UNDERWAY ACROSS WESTERN PART OF FORECAST AREA. RUC 850 MB WIND
ANALYSIS ALSO DEPICTING A DECREASE IN WIND SPEEDS. THUS...GUSTS IN
THE 20 TO 25 KT RANGE WILL BE FORECAST FOR ONLY KGUY AND KAMA...WITH
CESSATION OF SAME BEGINNING AROUND 23Z TODAY. LIGHT WESTERLY SURFACE
WINDS EXPECTED OVERNIHGT WITH NO VISIBILITY RESTRICTIONS EXPECTED.
VFR FORECAST CONTINUES NEXT 24 HOURS.
COCKRELL
&&
.PREV DISCUSSION... /ISSUED 540 AM CST SUN JAN 25 2015/
AVIATION...12Z TAFS
VFR CONDITIONS WILL PREVAIL. WINDS WILL GET GUSTY FROM THE NW TODAY
AND THEN DIE BACK DOWN AROUND SUNSET.
SIMPSON
PREV DISCUSSION... /ISSUED 420 AM CST SUN JAN 25 2015/
SHORT TERM...TODAY AND TONIGHT
A COLD FRONT THAT PUSHED THROUGH THE TEXAS/OKLAHOMA PANHANDLES LAST
NIGHT WILL CONTINUE TO MOVE SOUTHWARD TODAY. COLD AIR ASSOCIATED WITH
AN UPPER LEVEL DISTURBANCE OVER WESTERN MISSOURI WILL REMAIN NORTH OF
THE AREA SO THIS FRONT WILL HAVE LITTLE EFFECT ON THE TEMPERATURES
ACROSS THE AREA TODAY. MEANWHILE DRY NORTHWEST UPPER FLOW WILL
MAINTAIN A STRETCH OF DRY AND MILD CONDITIONS OVER THE AREA. HIGH
TEMPERATURES WILL BE A LITTLE WARMER TODAY DUE TO THE DIMINISHING
SNOW COVER...WITH HIGHS IN THE 50S TO AROUND 60 DEGREES. HOWEVER A
LOW-LEVEL JET OVER CENTRAL KANSAS/OKLAHOMA WILL LEAD TO BREEZY
NORTHWEST WINDS THAT CAN MAKE IT FEEL A BIT CHILLIER. THE STRONGEST
WINDS ARE EXPECTED TO BE OVER THE EASTERN OKLAHOMA AND NORTHEAST
TEXAS PANHANDLE...CLOSER TO THIS JET. WINDS WILL DIMINISH BY AROUND
SUNSET WHILE BACKING A BIT TO THE WEST. OVERNIGHT LOWS WILL BE
MILDER...RANGING FROM THE MID 20S IN THE NORTHWEST TO THE MID 30S IN
THE SOUTHEAST TEXAS PANHANDLE.
LONG TERM...MONDAY THROUGH SATURDAY
THE WARMING TREND WILL CONTINUE INTO THE FIRST PART OF THE EXTENDED
FORECAST AS AN AMPLIFIED UPPER-LEVEL RIDGE MOVES OVER THE ROCKIES TO
THE SOUTHERN PLAINS. DOWNSLOPING SOUTHWEST WINDS WILL PUSH
TEMPERATURES WELL INTO THE 60S AND EVEN LOW 70S MONDAY THROUGH
WEDNESDAY. HOWEVER THE RIDGE WILL START TO FLATTEN TUESDAY AS AN
UPPER-LEVEL DISTURBANCE LIFTS NORTHEAST OUT OF THE BAJA PENINSULA.
THIS SYSTEM WILL ALSO SEND A COLD FRONT THROUGH THE AREA WEDNESDAY
EVENING...COOLING HIGH TEMPERATURES BACK INTO THE 50S FOR THURSDAY.
THE UPPER PATTERN BECOMES MORE ACTIVE TOWARD THE END OF THE WEEK AS
ANOTHER UPPER LOW DEEPENS OVER BAJA CALIFORNIA. HOWEVER MUCH UNCERTAINTY
EXITS IN THE TRACK OF THIS SYSTEM ALONG WITH EVENTUAL PRECIP TYPE.
THE GFS CONTINUES TO GENERATE A LOT OF QPF ACROSS THE AREA AS
ISENTROPIC LIFT INCREASES ALONG WITH AN INFLUX OF LOW-LEVEL
MOISTURE. THE GFS ALSO TRACKS THIS UPPER LOW A LITTLE FURTHER TO THE
EAST THAN THE ECMWF. WHILE THIS SYSTEM HAS ITS ORIGINS IN THE
PACIFIC AND WITH THE COLD AIR WELL NORTH OF THE AREA INITIALLY...PRECIP
TYPE WILL START OUT AS RAIN FRIDAY. CAN SEE A RAIN SNOW MIX FRIDAY
EVENING AS TEMPERATURES COOL OFF TO NEAR THE FREEZING MARK. THE GFS
ALSO SUGGESTS MORE IN THE WAY OF WINTRY PRECIPITATION SATURDAY AS
IT BRINGS THE SOUTHERN FRINGES OF THE COLD AIR OVER THE GREAT LAKES
AREA FURTHER SOUTH THAN THE ECMWF.
PRECIP SHOULD END SUNDAY HOWEVER THIS UPPER LOW WILL EVENTUALLY LIFT
NORTHEAST INTO THE FOUR CORNERS REGION THE FOLLOWING WEEK. THIS IS
BEYOND THE SCOPE OF THIS FORECAST PACKAGE BUT BEARS WATCHING AS THIS
CAN BRING ANOTHER CHANCE OF PRECIPITATION TO THE AREA THEN.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
03/20
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 253 PM CST SUN JAN 25 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH
PRESSURE BUILDING SOUTHWARD OVER LAKE SUPERIOR EARLY THIS
AFTERNOON. A FEW POCKETS OF STRATO-CU REMAIN OVER THE FORECAST
AREA...BUT MAJORITY OF LOCATIONS HAVE CLEARED OUT. WILL SEE A SHORT
PERIOD OF MOSTLY CLEAR SKIES THIS AFTERNOON...THEN AN AREA OF
THINNING ALTO-CUMULUS WILL MOVE SOUTHEAST ACROSS NORTHERN
WISCONSIN. LOOKING FARTHER UPSTREAM...THE NEXT CLIPPER SYSTEM IS
MOVING SOUTHEAST INTO THE LAKE WINNIPEG REGION...AND POISED TO
ARRIVE LATE TONIGHT INTO MONDAY MORNING. SNOWFALL POTENTIAL WITH
THIS SYSTEM IS THE MAIN FORECAST CONCERN.
TONIGHT...LINGERING AREAS OF STRATO-CU OVER CENTRAL AND NORTHEAST
WISCONSIN WILL BE FADING BY SUNSET AS INCOMING ARCTIC HIGH AND VERY
DRY AIR OVERWHELM THE LOW LEVEL MOISTURE. POCKET OF MID-CLOUDS WILL
BE MOVING ACROSS THE FORECAST AREA AT THE START OF THE EVENING BUT
THINKING THESE CLOUDS WILL THIN/DIMINISH AS SUBSIDENCE INCREASES.
IF THIS OCCURS...THIS WILL LEAVE A FEW HOUR WINDOW FOR GOOD
RADIATIONAL COOLING OVER N-C WISCONSIN UNTIL CLOUDS INCREASE AGAIN
LATE IN THE EVENING. WILL DROP LOW TEMPS ACROSS N-C WISCONSIN AND
THEN SHOW RISING TEMPS AFTER MIDNIGHT. THE NEXT ALBERTA CLIPPER
WILL MAKE QUICK PROGRESS TONIGHT AND REACH THE BOUNDARY WATERS OF
NORTHERN MINNESOTA BY 12Z MON. WARM ADVECTION AHEAD OF THE CLIPPER
WILL CAUSE MID AND HIGH CLOUDS TO LOWER OVERNIGHT...WITH A CHANCE OF
SNOW ARRIVING OVER N-C WISCONSIN BETWEEN 09-12Z. UNCERTAINTY IS
RATHER HIGH WITH LOW TEMPS ACROSS N-C WISCONSIN...BUT WENT BELOW
GUIDANCE WITH LOWS RANGING FROM THE LOWER SINGLE DIGITS ABOVE ZERO
NORTH TO AROUND 10 ABOVE SOUTH.
MONDAY...LOW PRESSURE WILL CONTINUE TO MOVE SOUTHEAST AND WEAKEN AS
IT MOVES INTO NORTHWEST WISCONSIN BY 00Z. DECENT MID-LEVEL FGEN WILL
ACCOMPANY THE WARM ADVECTION OVER CENTRAL WISCONSIN DURING THE
MORNING BUT WILL GRADUALLY WEAKEN AS IT MOVES INTO EASTERN WISCONSIN
IN THE AFTERNOON. WITH SNOW RATIOS AROUND 15 TO 1...NORTH-CENTRAL
AND CENTRAL WISCONSIN COULD SEE AROUND 2 INCHES OF ACCUMULATION BY
THE END OF THE DAY WHILE EASTERN WISCONSIN SHOULD SEE AROUND AN INCH
OR LESS. THE SNOW MAY ALSO MIX WITH FREEZING DRIZZLE OVER CENTRAL
WISCONSIN BY LATE IN THE AFTERNOON AS MID-LEVEL MOISTURE BEGINS TO
PEEL OUT. WILL INCREASE PRECIP CHANCES SUBSTANTIALLY. HIGHS
RETURNING TO THE 20S AS WINDS SHIFT TO THE SOUTH.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 253 PM CST SUN JAN 25 2015
NORTHWEST UPPER FLOW WILL CONTINUE THOUGH AT LEAST
THE END OF THIS WEEK. WEAK CLIPPER SYSTEMS WILL MOVE THROUGH
MONDAY NIGHT AND AGAIN WEDNESDAY NIGHT AND THURSDAY AND AGAIN
SATURDAY. THE MIDWEEK CLIPPER SYSTEM PROBABLY HAS THE BEST CHANCE
OF PRODUCING MORE THAN AN INCH OR TWO OF SNOW DEPENDING ON HOW
MUCH PHASING THERE IS WITH SOUTHERN STREAM JET ENERGY PASSING BY
TO THE SOUTH.
THERE IS ALSO LIMITED MOISTURE WITH ALL THREE SYSTEMS SO DO NOT
EXPECT ANY BIG SNOWS THIS WEEK. UPPER HEIGHTS BUILD THROUGH MID
WEEK DESPITE THE FLOW BEING NORTHWEST. THIS SHOULD RESULT IN ABOVE
NORMAL TEMPERATURES. COLDER AIR WILL ARRIVE LATER THIS WEEK WITH
THE POSSIBILITY OF REAL ARCTIC AIR SUNDAY OR MONDAY OF THE
FOLLOWING WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1124 AM CST SUN JAN 25 2015
LOW STRATUS AND FLURRY ACTIVITY AS BEEN PERSISTENT SO FAR THIS
MORNING...BUT DRY AIR FROM THE LARGE ARCTIC AIR IS STARTING TO MAKE
INROADS OVER NORTHERN LAKE MICHIGAN. BREAKS IN THE CLOUDS ARE ALSO
DEVELOPING OVER NORTHERN WISCONSIN. ANTICIPATE THESE TRENDS TO
CONTINUE THIS AFTERNOON AS THE ARCTIC HIGH MOVES SOUTH OVER LAKE
SUPERIOR...AND SKY CONDITIONS TO TURN VFR BY MID TO LATE AFTERNOON.
GUSTY NORTHEAST WINDS WILL ALSO DIMINISH LATER THIS AFTERNOON AS
WELL.
AFTER A PERIOD OF PARTLY CLOUDY AND VFR CONDITIONS...EXPECT MID AND
HIGH CLOUDS TO INCREASE AGAIN LATER THIS EVENING AHEAD OF THE NEXT
CLIPPER. SNOW FROM THE CLIPPER TO ARRIVE MONDAY MORNING OVER
NORTH-CENTRAL WISCONSIN...WHICH WILL DROP VSBYS TO IFR AND CIGS TO
AT LEAST LOW MVFR. THE SNOW IS EXPECTED TO REACH EASTERN WISCONSIN
AROUND MIDDAY. AN INCH OR TWO WILL BE POSSIBLE BY LATE MONDAY
AFTERNOON.
MPC.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC