Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/12/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
750 PM MST SUN JAN 11 2015
.SYNOPSIS...
UNSETTLED WEATHER WILL CONTINUE TO BE THE STORY THROUGH THE EARLY
PART OF THE WEEK...AS THE LAST TWO IN A SERIES OF FAST MOVING
DISTURBANCES AFFECT THE DESERT SOUTHWEST. SCATTERED SHOWERS WILL
MOVE THROUGH THE AREA INTO THE MORNING HOURS MONDAY...FOLLOWED BY
LINGERING SHOWERS MAINLY ACROSS HIGHER TERRAIN AREAS NORTH AND EAST
OF PHOENIX THROUGH MONDAY AFTERNOON. ANOTHER SYSTEM WILL BRING
CHANCES OF SHOWERS TO EASTERN ARIZONA DURING THE DAYTIME HOURS
TUESDAY. HIGH PRESSURE WILL RETURN TO THE AREA BY MID WEEK WITH DRY
WEATHER AND SLOWLY INCREASING TEMPERATURES EXPECTED FROM WEDNESDAY
INTO NEXT WEEKEND.
&&
.DISCUSSION...
THE PRIMARY PV ANOMALY AND COLD CORE ALOFT HAS MOVED ONSHORE NORTH
OF SAN DIEGO THIS EVENING...WITH A SECONDARY LEAD WAVE/MESO-VORTEX
QUITE EVIDENT IN RADAR AND SATELLITE IMAGERY EJECTING NORTH FROM THE
GULF OF CALIFORNIA. THIS SECONDARY FEATURE APPEARS TO BE IN THE
INITIAL STAGES OF BECOMING ABSORBED BY THE LARGER CIRCULATION
CENTER...HOWEVER ITS PRESENCE IS CREATING ENHANCED UPPER LEVEL
DIFLUENCE AND GREATER OVERALL VORTICITY FORCED ASCENT. PER REGIONAL
MESOANALYSIS...THE LEAD WING OF VORTICITY HAS BEEN ACTING ON A NOSE
OF BETTER LOW LEVEL LAPSE RATES AND FRONTOGENESIS WHILE DEFORMATION
STRUCTURE EXISTS THROUGH SERN CALIFORNIA.
REGIONAL 00Z SOUNDINGS DEPICTING AMPLE MOISTURE AND PWATS BELOW THE
H5 LEVEL (0.7-1.0 INCHES) ALONG WITH RADAR TRENDS SUGGEST PERSISTENT
SHOWERS THROUGHOUT THE OVERNIGHT HOURS. HIGH RESOLUTION MODELS
INCLUDING THE HRRR AND ESPECIALLY 4KM WRF-NMM SEEM TO HAVE THE BEST
SOLUTION BASED ON FORECAST/VERIFIED RADAR REFLECTIVITIES. AS
SUCH...HAVE MADE FURTHER TARGETED INCREASES TO RAINFALL CHANCES
OVERNIGHT...ALBEIT WITH STILL LIGHT ACCUMULATIONS. OTHERWISE WITH
RAINFALL ALREADY REACHING THE SFC AND WETBULBING OCCURRING...HAVE
MADE RATHER SUBSTANTIAL INCREASES TO DEWPOINTS AND RELATIVE
HUMIDITIES OVERNIGHT...WHILE BUMPING UP FORECAST LOWS SLIGHTLY BASED
ON EXTENSIVE THICK CLOUD COVER.
&&
.PREVIOUS DISCUSSION...
/305 PM MST SUN JAN 11 2015/
BY MONDAY MORNING...THE TROUGH IS FORECAST TO BE CENTERED OVER
SOUTH-CENTRAL ARIZONA ALLOWING SHOWERS TO END FOR THE MOST PART
ACROSS SOUTHWEST ARIZONA WITH LINGERING ISOLATED TO SCATTERED
SHOWERS MAINLY FOCUSED OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX THROUGH MONDAY AFTERNOON. WE SHOULD SEE SOME DRYING AND
CLEARING SKIES IN OUR WESTERN AREAS ON MONDAY...BUT SOME MOISTURE
WILL LINGER OVER ARIZONA AS ANOTHER SHORTWAVE TROUGH APPROACHES FROM
OUT OF THE GREAT BASIN. MODELS HAVE FINALLY COME INTO BETTER
AGREEMENT INDICATING THAT THE LAST TROUGH WILL MAINLY BE A GLANCING
BLOW FOR US...MOSTLY AFFECTING NORTHERN AND FAR EASTERN ARIZONA.
SHOWER CHANCES FOR THIS SYSTEM ARE FOCUSED OVER HIGHER TERRAIN AREAS
EAST OF PHOENIX WITH JUST A SLIGHT CHANCE OVER THE EAST VALLEY. THIS
SYSTEM WILL USHER IN MUCH DRIER AIR BEHIND A COLD FRONT...REACHING
OUR WESTERN AREAS BY NOON TUESDAY AND THEN THROUGH THE REST OF THE
AREA BY LATE TUESDAY AFTERNOON. THIS WILL ALSO BRING SOME GUSTY
WINDS DOWN THE LOWER COLORADO RIVER VALLEY STARTING TUESDAY
AFTERNOON AND THEN INTO SOUTH-CENTRAL ARIZONA TUESDAY NIGHT INTO
WEDNESDAY MORNING. MAY SEE SOME WIND GUSTS TO 35 MPH ALONG RIDGETOPS
AND HIGHER PEAKS...BUT NOT ENOUGH TO WORRY ABOUT ANY WIND ADVISORIES.
LOOKING AHEAD TO WEDNESDAY AND BEYOND...RIDGING WILL RETURN TO THE
AREA BUT NOT NEARLY TO THE EXTENT AS WAS SEEN A FEW DAYS AGO. THIS
SHOULD RESULT IN GRADUALLY INCREASING TEMPERATURES AND LITTLE TO NO
CHANCE OF PRECIPITATION ACROSS THE AREA. HIGHS WILL EVENTUALLY CREEP
BACK INTO THE MID 70S BY LATE WEEK/NEXT WEEKEND.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
CLOUDS WILL CONTINUE TO LOWER AND THICKEN EARLY THIS EVENING AHEAD
OF A LOW PRESSURE SYSTEM SLIDING EASTWARD THROUGH SOUTHERN CA/AZ.
SCATTERED SHOWERS ARE EXPECTED TO DEVELOP IN THE PHOENIX AREA
BETWEEN 01Z AND 04Z...CONTINUING THROUGH AROUND 15Z. CIGS WILL
GENERALLY LOWER TO AROUND 7K FT...HOWEVER OCCASIONAL CIGS DOWN TO 5K
FT ARE POSSIBLE IN SHOWERS. IMPROVING CONDITIONS ARE ANTICIPATED
LATE MONDAY MORNING AS THE DEEPER MOISTURE AND SHOWER ACTIVITY
TRANSITION INTO THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX.
OTHERWISE...WINDS WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SCATTERED SHOWERS ASSOCIATED WITH A LOW PRESSURE SYSTEM WILL PERSIST
THROUGH 08-09Z. THEREAFTER...CONDITIONS WILL IMPROVE WITH CLOUDS
BECOMING SCT-BKN THROUGH MONDAY MORNING.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
TUESDAY WILL SEE THE FINAL IN A SERIES OF TROUGHS MOVE THROUGH THE
AREA. LOOKS LIKE THE BEST CHANCE OF PRECIPITATION WILL BE IN THE
MOUNTAINS EAST OF PHOENIX. SHOWERS SHOULD TAPER OFF QUICKLY TUESDAY
NIGHT WITH DRY WEATHER FORECAST WEDNESDAY INTO THE WEEKEND. THERE
COULD ALSO BE SOME LOCALIZED BREEZINESS WITH THE TUESDAY SYSTEM
ESPECIALLY DOWN THE COLORADO RIVER AND ACROSS THE RIDGETOPS EAST OF
PHOENIX. NOTHING HIGH ENOUGH TO WARRANT ANY FIRE WEATHER HEADLINES
THOUGH. AS FOR MOISTURE...HUMIDITIES WILL DROP A BIT FROM MID WEEK
ONWARD YET AFTERNOON READINGS WILL ONLY DROP INTO THE 20-30 PERCENT
RANGE WITH GOOD OVERNIGHT RECOVERIES EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MO/KUHLMAN/LEINS
AVIATION...HIRSCH
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
250 PM MST SAT JAN 10 2015
.SYNOPSIS...
A SERIES OF FAST MOVING WEATHER DISTURBANCES WILL AFFECT THE REGION
THROUGH EARLY NEXT WEEK BRINGING A HIGHER THAN NORMAL CHANCE OF
SHOWERS TO THE AREA. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL
THROUGH SUNDAY BEFORE DROPPING BACK NEAR NORMAL EARLY NEXT WEEK. DRY
CONDITIONS AND SLIGHTLY ABOVE NORMAL TEMPERATURES WILL RETURN TO THE
AREA TUESDAY AND WEDNESDAY...REMAINING IN PLACE THROUGH THE END OF
THE WEEK.
&&
.DISCUSSION...
LATEST RAP ANALYZED THE MID-TROPOSPHERIC TROUGH AND VORT MAX ALONG
THE CO RIVER VALLEY. ORGANIZED ASCENT AHEAD OF THE TROUGH AXIS HAS
PRODUCED WIDESPREAD CLOUDINESS STRETCHING FROM WESTERN MARICOPA
COUNTY NORTHWARD INTO UT. SMALLER VORTICES WITHIN THIS LINE OF
CLOUDS HAVE ALSO SUPPORTED SCATTERED SHOWER ACTIVITY ACROSS WESTERN
AND CENTRAL AZ. VIRGA...SPRINKLES AND EVEN SOME SHOWERS HAVE ALSO
MANAGED TO DEVELOP AS FAR EAST AS THE PHOENIX AREA THIS
AFTERNOON...THOUGH THE AREAL EXTENT OF THE PRECIPITATION WAS NOT
HANDLED WELL BY THE 12Z LOCAL WRFS. HRRR WITH ITS RADAR ASSIMILATION
HAS BEEN A BETTER GUIDANCE OPTION AND SUGGESTS THE ACTIVITY WILL
CONTINUE LIFTING TO THE NORTH AND EAST THROUGH EASTERN MARICOPA AND
GILA COUNTIES LATE THIS AFTERNOON AND EARLY THIS EVENING.
NEXT IN A SERIES OF TROUGHS WILL SLIDE SOUTHEASTWARD TOWARDS THE SAN
DIEGO COAST SUNDAY NIGHT. AHEAD OF THIS SYSTEM...PACIFIC MOISTURE
WILL CONTINUE TO STREAM EASTWARD RESULTING IN MOSTLY CLOUDY SKIES
ACROSS MUCH OF THE AREA. MODEL CONSENSUS SUGGESTS THAT LIGHT
PRECIPITATION WILL AGAIN DEVELOP ACROSS THE LOWER DESERTS SUNDAY
NIGHT AND MONDAY MORNING AHEAD OF THE TROUGH IN THE ASCENDING
REGION. POPS WERE FINE-TUNED BASED ON THE LATEST GUIDANCE...WHICH
EQUATES TO MORE OR LESS ISOLATED-SCATTERED ACTIVITY WITH LOW QPFS.
BY MONDAY AFTERNOON...ECMWF/GFS/NAM-WRF DEPICT STRONG Q DIVERGENCE
AND A BRIEF BUT DISCERNIBLE PERIOD OF SUBSIDENCE AHEAD OF THE NEXT
SYSTEM.
&&
.PREVIOUS DISCUSSION...
FINALLY THE THIRD TROUGH WILL MOVE ONSHORE AND THROUGH ARIZONA
MONDAY NIGHT-TUESDAY. AT THIS POINT IT LOOKS LIKE THE OVER-LAND
TRAJECTORY OF THIS WAVE WILL PRECLUDE WIDESPREAD PRECIP AND ONLY THE
HIGHEST ELEVATIONS NORTH/EAST OF PHOENIX WILL SEE ANY PRECIP WITH
THIS TROUGH. I RETAINED A MENTION OF SHOWERS EAST OF PHOENIX THROUGH
THE DAY TUESDAY BUT CONDITIONS SHOULD DRY OUT QUICKLY TUESDAY NIGHT.
MIXING RATIOS FORECAST TO PLUMMET QUICKLY TUESDAY
NIGHT...EFFECTIVELY ENDING OUT PERIOD OF UNSETTLED WEATHER.
GENERALLY SPEAKING THE MODELS ARE IN DECENT AGREEMENT FROM WEDNESDAY
ONWARD YET THERE ARE SOME SUBTLE DIFFERENCES WITH THE POSITION OF A
NEARBY RIDGE AND THE POSSIBILITY OF A VERY WEAK UPPER LEVEL LOW THAT
COULD DRIFT THROUGH THE AREA LATE NEXT WEEK. ALL MODELS AGREE THAT
BL MIXING RATIOS AND PWATS WILL REMAIN BELOW CLIMO THROUGH THIS
PERIOD...THUS AT THIS POINT THE ONLY FORECAST QUESTIONS ARE CENTERED
ON CLOUD COVER AND TEMPERATURES. SHOULD SEE VARYING AMOUNTS OF HIGH
CLOUDS FROM WEDNESDAY ONWARD BUT NOTHING OF MUCH SIGNIFICANCE.
BLENDED CONSENSUS GUIDANCE SUGGESTS STEADILY INCREASING TEMPERATURES
TUESDAY THROUGH SATURDAY WHICH MATCHES THE INHERITED GRIDS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...AND
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A WEAK LOW PRESSURE SYSTEM WILL BRING ISOLATED SHOWERS TO
SOUTH-CENTRAL ARIZONA INCLUDING THE PHOENIX TERMINALS THROUGH THE
REST OF THE AFTERNOON. AM EXPECTING MOSTLY BROKEN CLOUD DECKS
BETWEEN 7-10K FEET FORMING BY EARLY EVENING AND PERSISTING INTO
SUNDAY. ANOTHER ROUND OF LIGHT SHOWERS IS LIKELY ACROSS SOUTHEAST
CALIFORNIA AFTER SUNRISE SUNDAY...POSSIBLY AFFECTING KIPL AND
KBLH...BUT VFR CONDITIONS WILL PREVAIL. WINDS WILL REMAIN BELOW 10
KTS WITH A PREDOMINANTLY EASTERLY DIRECTION FOR THE PHOENIX AREA AND
MOSTLY VARIABLE WINDS FOR SOUTHEAST CALIFORNIA.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
TWO TROUGHS WILL MOVE THROUGH THE REGION EARLY NEXT WEEK. RAINFALL
AMOUNTS WILL BE LIGHT BUT COULD AFFECT THE LOWER DESERTS AND POINTS
EAST OF THE COLORADO RIVER. SLIGHTLY HIGHER AMOUNTS ARE ANTICIPATED
IN THE MOUNTAINS NORTH/EAST OF PHOENIX. ANOTHER TROUGH WILL MOVE
THROUGH THE AREA ON TUESDAY AND ANY PRECIP SHOULD BE ISOLATED TO THE
MOUNTAINS AROUND GLOBE/HILLTOP/SUNFLOWER. AFTER THAT...DRY WEATHER
AND LOWER HUMIDITIES ARE EXPECTED ACROSS THE AREA. AFTERNOON
HUMIDITIES MONDAY AND TUESDAY WILL ONLY DROP INTO THE 30-50 PERCENT
RANGE WITH SLIGHTLY LOWER VALUES WEDNESDAY THROUGH FRIDAY. OVERNIGHT
RECOVERIES WILL BE GOOD. NO MAJOR WIND EVENTS EXPECTED...GENERALLY
EXPECTING LIGHT DIURNALLY DRIVEN PATTERNS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...KUHLMAN
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1255 PM MST SAT JAN 10 2015
.UPDATE...UPDATED AVIATION DISCUSSION...
&&
.SYNOPSIS...
A SERIES OF FAST MOVING WEATHER DISTURBANCES WILL AFFECT THE REGION
THROUGH EARLY NEXT WEEK BRINGING AN ELEVATED CHANCE OF SHOWERS TO
THE AREA...ESPECIALLY ON MONDAY. TEMPERATURES WILL REMAIN SLIGHTLY
ABOVE NORMAL THROUGH SUNDAY BEFORE DROPPING BACK NEAR NORMAL EARLY
NEXT WEEK. DRY CONDITIONS AND SLIGHTLY ABOVE NORMAL TEMPERATURES
WILL RETURN TO THE AREA TUESDAY AND WEDNESDAY...REMAINING IN PLACE
THROUGH THE END OF THE WEEK.
&&
.DISCUSSION...
SHORT-WAVE TROUGH IN THE MOJAVE DESERT CONTINUES TO LIFT
NORTHEASTWARD THIS MORNING. SCATTERED SHOWERS HAVE DEVELOPED AHEAD
OF THE TROUGH AXIS...MAINLY ACROSS LA PAZ AND WESTERN MARICOPA
COUNTIES. A FEW LIGHTNING STRIKES HAVE ALSO BEEN DETECTED AND ARE
ASSOCIATED WITH AN AREA OF WEAK INSTABILITY AND STRONGER FORCING FOR
ASCENT JUST EAST OF THE VORT MAX. THUNDER WAS ADDED TO THE FORECAST
FOR THIS MORNING FOR THE AFOREMENTIONED AREAS.
LATEST HRRR APPEARS REASONABLE AND INDICATES THAT THE CONVECTION
WILL MAINLY BE FOCUSED ACROSS NORTHERN AND WESTERN MARICOPA COUNTY
THROUGH THE REST OF TODAY AS THE TROUGH LIFTS NORTHEASTWARD AND
WEAKENS. THERE IS ALSO SOME POTENTIAL FOR ISOLATED SHOWERS WORKING
THEIR WAY INTO THE PHOENIX AREA...THOUGH THE GREATEST THREAT WILL BE
FROM THE WEST VALLEY NORTH AND WESTWARD. IN THE PHOENIX
AREA...FORECAST POPS ARE BETWEEN 10 AND 20 PERCENT...WHICH IS
GENERALLY ABOVE THE MEDIAN OF THE GUIDANCE. NO SIGNIFICANT CHANGES
TO THE FORECAST ARE ANTICIPATED. THIS AFTERNOON...THE THREAT OF
PRECIPITATION WILL DECREASE AS SUBSIDENCE INCREASES BEHIND THE
TROUGH.
&&
.PREVIOUS DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY REVEALS A SERIES OF SHORTWAVE
TROUGHS ACROSS THE EASTERN PACIFIC...ALL OF WHICH WILL PLAY A ROLE
IN THE WEATHER ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL ARIZONA
THROUGH EARLY NEXT WEEK. THE FIRST WAS MOVING THROUGH CENTRAL
CALIFORNIA THIS MORNING...WITH A SECONDARY TROUGH NEAR
35N/130W...AND YET ANOTHER THROUGH NEAR 40N/145W. REGIONAL RADAR
MOSAIC INDICATES A FEW VERY LIGHT SHOWERS ACROSS PORTIONS OF
SOUTHEAST CALIFORNIA /GENERALLY ACROSS EASTERN RIVERSIDE AND
NORTHERN IMPERIAL COUNTIES/. SURFACE DEWPOINTS IN THESE AREAS ARE
ONLY IN THE LOWER 40S AND MORE THAN LIKELY THESE ARE ONLY
SPRINKLES/VIRGA/VERY LIGHT RAIN SHOWERS...NOTHING OF TOO MUCH
CONCERN. DEWPOINTS WERE SLIGHTLY LOWER ACROSS ARIZONA WITH READINGS
GENERALLY IN THE MID 30S ACROSS THE PHOENIX AREA AS OF 09Z.
BEST FORCING IS GOING TO BE DISPLACED WELL NORTH OF THE PHOENIX AREA
AND LATEST 00Z-06Z GUIDANCE SUGGESTS ONLY A FEW SPRINKLES OR VERY
LIGHT SHOWERS ACROSS THE DESERTS. THE HIGHER TERRAIN LOCATIONS
STRETCHING FROM WICKENBURG TO SUNFLOWER AND GLOBE/HILLTOP HAVE
SLIGHTLY BETTER CHANCES OF SEEING RAINFALL AT SOME POINT TODAY...BUT
ELSEWHERE IT WILL BE A STRUGGLE. BUFR SOUNDINGS CONFIRM A RELATIVELY
DEEP DRY SUB-CLOUD LAYER AT NEARLY EVERY DESERT SITE TODAY AND POPS
WERE ADJUSTED SLIGHTLY DOWNWARD IN MOST LOCATIONS. PRECIP AMOUNTS
WILL BE LIGHT...GENERALLY A FEW HUNDREDTHS OF AN INCH. WITH SNOW
LEVELS IN THE 7500-8500FT RANGE...MIXED PRECIP IS NOT A CONCERN
ACROSS OUR FORECAST AREA.
LOOKING FORWARD TO TONIGHT AND SUNDAY THERE WILL BE A BRIEF PERIOD
OF POST-FRONTAL SUBSIDENCE WHICH SHOULD RESULT IN A QUIET PERIOD OF
WEATHER EARLY SUNDAY MORNING. HOWEVER THE SECOND TROUGH WILL QUICKLY
APPROACH THE AREA SUNDAY AFTERNOON WITH INCREASING CLOUDS AND PWATS
EXPECTED BEFORE 00Z MONDAY. PREVIOUS MODEL RUNS SUGGESTED THIS
TROUGH WOULD HOLD OFF UNTIL MONDAY MORNING BUT THE MORE PROGRESSIVE
NATURE OF THE WAVE SUGGESTS IT WILL ARRIVE ABOUT 6-12HRS SOONER THAN
I WAS THINKING YESTERDAY. ALSO...BL MIXING RATIOS WILL BE A BIT
HIGHER WITH THIS SECONDARY TROUGH AND THUS PRECIP CHANCES WILL BE
SLIGHTLY HIGHER. POPS WERE INCREASED SOMEWHAT WITH THE MAIN FOCUS IN
THE 06Z-18Z PERIOD MONDAY. STILL THINKING THE BIGGEST IMPACT WILL BE
ON THE MONDAY MORNING COMMUTE ACROSS THE DESERTS BUT NEARLY ALL
ENSEMBLE MEAN QPFS ACROSS THE REGION HAVE DECREASED. MAY END UP
BEING A FEW HUNDREDTHS OF AN INCH OF RAIN AT MOST.
FINALLY THE THIRD TROUGH WILL MOVE ONSHORE AND THROUGH ARIZONA ON
TUESDAY. AT THIS POINT IT LOOKS LIKE THE OVER-LAND TRAJECTORY OF
THIS WAVE WILL PRECLUDE WIDESPREAD PRECIP AND ONLY THE HIGHEST
ELEVATIONS NORTH/EAST OF PHOENIX WILL SEE ANY PRECIP WITH THIS
TROUGH. I RETAINED A MENTION OF SHOWERS EAST OF PHOENIX THROUGH THE
DAY TUESDAY BUT CONDITIONS SHOULD DRY OUT QUICKLY TUESDAY NIGHT.
MIXING RATIOS FORECAST TO PLUMMET QUICKLY TUESDAY
NIGHT...EFFECTIVELY ENDING OUT PERIOD OF UNSETTLED WEATHER.
GENERALLY SPEAKING THE MODELS ARE IN DECENT AGREEMENT FROM WEDNESDAY
ONWARD YET THERE ARE SOME SUBTLE DIFFERENCES WITH THE POSITION OF A
NEARBY RIDGE AND THE POSSIBILITY OF A VERY WEAK UPPER LEVEL LOW THAT
COULD DRIFT THROUGH THE AREA LATE NEXT WEEK. ALL MODELS AGREE THAT
BL MIXING RATIOS AND PWATS WILL REMAIN BELOW CLIMO THROUGH THIS
PERIOD...THUS AT THIS POINT THE ONLY FORECAST QUESTIONS ARE CENTERED
ON CLOUD COVER AND TEMPERATURES. SHOULD SEE VARYING AMOUNTS OF HIGH
CLOUDS FROM WEDNESDAY ONWARD BUT NOTHING OF MUCH SIGNIFICANCE.
BLENDED CONSENSUS GUIDANCE SUGGESTS STEADILY INCREASING TEMPERATURES
TUESDAY THROUGH SATURDAY WHICH MATCHES THE INHERITED GRIDS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...AND
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A WEAK LOW PRESSURE SYSTEM WILL BRING ISOLATED SHOWERS TO
SOUTH-CENTRAL ARIZONA INCLUDING THE PHOENIX TERMINALS THROUGH THE
REST OF THE AFTERNOON. AM EXPECTING MOSTLY BROKEN CLOUD DECKS
BETWEEN 7-10K FEET FORMING BY EARLY EVENING AND PERSISTING INTO
SUNDAY. ANOTHER ROUND OF LIGHT SHOWERS IS LIKELY ACROSS SOUTHEAST
CALIFORNIA AFTER SUNRISE SUNDAY...POSSIBLY AFFECTING KIPL AND
KBLH...BUT VFR CONDITIONS WILL PREVAIL. WINDS WILL REMAIN BELOW 10
KTS WITH A PREDOMINANTLY EASTERLY DIRECTION FOR THE PHOENIX AREA AND
MOSTLY VARIABLE WINDS FOR SOUTHEAST CALIFORNIA.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
TWO TROUGHS WILL MOVE THROUGH THE REGION EARLY NEXT WEEK. RAINFALL
AMOUNTS WILL BE LIGHT BUT COULD AFFECT THE LOWER DESERTS AND POINTS
EAST OF THE COLORADO RIVER. SLIGHTLY HIGHER AMOUNTS ARE ANTICIPATED
IN THE MOUNTAINS NORTH/EAST OF PHOENIX. ANOTHER TROUGH WILL MOVE
THROUGH THE AREA ON TUESDAY AND ANY PRECIP SHOULD BE ISOLATED TO THE
MOUNTAINS AROUND GLOBE/HILLTOP/SUNFLOWER. AFTER THAT...DRY WEATHER
AND LOWER HUMIDITIES ARE EXPECTED ACROSS THE AREA. AFTERNOON
HUMIDITIES MONDAY AND TUESDAY WILL ONLY DROP INTO THE 30-50 PERCENT
RANGE WITH SLIGHTLY LOWER VALUES WEDNESDAY THROUGH FRIDAY. OVERNIGHT
RECOVERIES WILL BE GOOD. NO MAJOR WIND EVENTS EXPECTED...GENERALLY
EXPECTING LIGHT DIURNALLY DRIVEN PATTERNS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...KUHLMAN
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
940 AM MST SAT JAN 10 2015
.SYNOPSIS...
A SERIES OF FAST MOVING WEATHER DISTURBANCES WILL AFFECT THE REGION
THROUGH EARLY NEXT WEEK BRINGING AN ELEVATED CHANCE OF SHOWERS TO
THE AREA...ESPECIALLY ON MONDAY. TEMPERATURES WILL REMAIN SLIGHTLY
ABOVE NORMAL THROUGH SUNDAY BEFORE DROPPING BACK NEAR NORMAL EARLY
NEXT WEEK. DRY CONDITIONS AND SLIGHTLY ABOVE NORMAL TEMPERATURES
WILL RETURN TO THE AREA TUESDAY AND WEDNESDAY...REMAINING IN PLACE
THROUGH THE END OF THE WEEK.
&&
.DISCUSSION...
SHORT-WAVE TROUGH IN THE MOJAVE DESERT CONTINUES TO LIFT
NORTHEASTWARD THIS MORNING. SCATTERED SHOWERS HAVE DEVELOPED AHEAD
OF THE TROUGH AXIS...MAINLY ACROSS LA PAZ AND WESTERN MARICOPA
COUNTIES. A FEW LIGHTNING STRIKES HAVE ALSO BEEN DETECTED AND ARE
ASSOCIATED WITH AN AREA OF WEAK INSTABILITY AND STRONGER FORCING FOR
ASCENT JUST EAST OF THE VORT MAX. THUNDER WAS ADDED TO THE FORECAST
FOR THIS MORNING FOR THE AFOREMENTIONED AREAS.
LATEST HRRR APPEARS REASONABLE AND INDICATES THAT THE CONVECTION
WILL MAINLY BE FOCUSED ACROSS NORTHERN AND WESTERN MARICOPA COUNTY
THROUGH THE REST OF TODAY AS THE TROUGH LIFTS NORTHEASTWARD AND
WEAKENS. THERE IS ALSO SOME POTENTIAL FOR ISOLATED SHOWERS WORKING
THEIR WAY INTO THE PHOENIX AREA...THOUGH THE GREATEST THREAT WILL BE
FROM THE WEST VALLEY NORTH AND WESTWARD. IN THE PHOENIX
AREA...FORECAST POPS ARE BETWEEN 10 AND 20 PERCENT...WHICH IS
GENERALLY ABOVE THE MEDIAN OF THE GUIDANCE. NO SIGNIFICANT CHANGES
TO THE FORECAST ARE ANTICIPATED. THIS AFTERNOON...THE THREAT OF
PRECIPITATION WILL DECREASE AS SUBSIDENCE INCREASES BEHIND THE
TROUGH.
&&
.PREVIOUS DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY REVEALS A SERIES OF SHORTWAVE
TROUGHS ACROSS THE EASTERN PACIFIC...ALL OF WHICH WILL PLAY A ROLE
IN THE WEATHER ACROSS SOUTHEAST CALIFORNIA AND SOUTH-CENTRAL ARIZONA
THROUGH EARLY NEXT WEEK. THE FIRST WAS MOVING THROUGH CENTRAL
CALIFORNIA THIS MORNING...WITH A SECONDARY TROUGH NEAR
35N/130W...AND YET ANOTHER THROUGH NEAR 40N/145W. REGIONAL RADAR
MOSAIC INDICATES A FEW VERY LIGHT SHOWERS ACROSS PORTIONS OF
SOUTHEAST CALIFORNIA /GENERALLY ACROSS EASTERN RIVERSIDE AND
NORTHERN IMPERIAL COUNTIES/. SURFACE DEWPOINTS IN THESE AREAS ARE
ONLY IN THE LOWER 40S AND MORE THAN LIKELY THESE ARE ONLY
SPRINKLES/VIRGA/VERY LIGHT RAIN SHOWERS...NOTHING OF TOO MUCH
CONCERN. DEWPOINTS WERE SLIGHTLY LOWER ACROSS ARIZONA WITH READINGS
GENERALLY IN THE MID 30S ACROSS THE PHOENIX AREA AS OF 09Z.
BEST FORCING IS GOING TO BE DISPLACED WELL NORTH OF THE PHOENIX AREA
AND LATEST 00Z-06Z GUIDANCE SUGGESTS ONLY A FEW SPRINKLES OR VERY
LIGHT SHOWERS ACROSS THE DESERTS. THE HIGHER TERRAIN LOCATIONS
STRETCHING FROM WICKENBURG TO SUNFLOWER AND GLOBE/HILLTOP HAVE
SLIGHTLY BETTER CHANCES OF SEEING RAINFALL AT SOME POINT TODAY...BUT
ELSEWHERE IT WILL BE A STRUGGLE. BUFR SOUNDINGS CONFIRM A RELATIVELY
DEEP DRY SUB-CLOUD LAYER AT NEARLY EVERY DESERT SITE TODAY AND POPS
WERE ADJUSTED SLIGHTLY DOWNWARD IN MOST LOCATIONS. PRECIP AMOUNTS
WILL BE LIGHT...GENERALLY A FEW HUNDREDTHS OF AN INCH. WITH SNOW
LEVELS IN THE 7500-8500FT RANGE...MIXED PRECIP IS NOT A CONCERN
ACROSS OUR FORECAST AREA.
LOOKING FORWARD TO TONIGHT AND SUNDAY THERE WILL BE A BRIEF PERIOD
OF POST-FRONTAL SUBSIDENCE WHICH SHOULD RESULT IN A QUIET PERIOD OF
WEATHER EARLY SUNDAY MORNING. HOWEVER THE SECOND TROUGH WILL QUICKLY
APPROACH THE AREA SUNDAY AFTERNOON WITH INCREASING CLOUDS AND PWATS
EXPECTED BEFORE 00Z MONDAY. PREVIOUS MODEL RUNS SUGGESTED THIS
TROUGH WOULD HOLD OFF UNTIL MONDAY MORNING BUT THE MORE PROGRESSIVE
NATURE OF THE WAVE SUGGESTS IT WILL ARRIVE ABOUT 6-12HRS SOONER THAN
I WAS THINKING YESTERDAY. ALSO...BL MIXING RATIOS WILL BE A BIT
HIGHER WITH THIS SECONDARY TROUGH AND THUS PRECIP CHANCES WILL BE
SLIGHTLY HIGHER. POPS WERE INCREASED SOMEWHAT WITH THE MAIN FOCUS IN
THE 06Z-18Z PERIOD MONDAY. STILL THINKING THE BIGGEST IMPACT WILL BE
ON THE MONDAY MORNING COMMUTE ACROSS THE DESERTS BUT NEARLY ALL
ENSEMBLE MEAN QPFS ACROSS THE REGION HAVE DECREASED. MAY END UP
BEING A FEW HUNDREDTHS OF AN INCH OF RAIN AT MOST.
FINALLY THE THIRD TROUGH WILL MOVE ONSHORE AND THROUGH ARIZONA ON
TUESDAY. AT THIS POINT IT LOOKS LIKE THE OVER-LAND TRAJECTORY OF
THIS WAVE WILL PRECLUDE WIDESPREAD PRECIP AND ONLY THE HIGHEST
ELEVATIONS NORTH/EAST OF PHOENIX WILL SEE ANY PRECIP WITH THIS
TROUGH. I RETAINED A MENTION OF SHOWERS EAST OF PHOENIX THROUGH THE
DAY TUESDAY BUT CONDITIONS SHOULD DRY OUT QUICKLY TUESDAY NIGHT.
MIXING RATIOS FORECAST TO PLUMMET QUICKLY TUESDAY
NIGHT...EFFECTIVELY ENDING OUT PERIOD OF UNSETTLED WEATHER.
GENERALLY SPEAKING THE MODELS ARE IN DECENT AGREEMENT FROM WEDNESDAY
ONWARD YET THERE ARE SOME SUBTLE DIFFERENCES WITH THE POSITION OF A
NEARBY RIDGE AND THE POSSIBILITY OF A VERY WEAK UPPER LEVEL LOW THAT
COULD DRIFT THROUGH THE AREA LATE NEXT WEEK. ALL MODELS AGREE THAT
BL MIXING RATIOS AND PWATS WILL REMAIN BELOW CLIMO THROUGH THIS
PERIOD...THUS AT THIS POINT THE ONLY FORECAST QUESTIONS ARE CENTERED
ON CLOUD COVER AND TEMPERATURES. SHOULD SEE VARYING AMOUNTS OF HIGH
CLOUDS FROM WEDNESDAY ONWARD BUT NOTHING OF MUCH SIGNIFICANCE.
BLENDED CONSENSUS GUIDANCE SUGGESTS STEADILY INCREASING TEMPERATURES
TUESDAY THROUGH SATURDAY WHICH MATCHES THE INHERITED GRIDS.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...AND
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
HIGH CLOUDS GRADUALLY THICKEN AND CIGS EVENTUALLY LOWER TO 8-10KFT
LATER TODAY. ALMOST ALL PRECIPITATION REACHING THE SURFACE WILL BE
RELEGATED TO NORTHERN ARIZONA...HOWEVER EXTENSIVE VIRGA AND A FEW
SPRINKLES WILL BE POSSIBLE LATER THIS MORNING NEAR KBLH...AND NEAR
KPHX/KIWA/KSDL AFTER 20Z THIS AFTERNOON. LOW PRESSURE OVER SOUTHERN
CALIFORNIA WILL FACILITATE LIGHT AND VARIABLE SURFACE WINDS THROUGH
AT LEAST 10Z SUNDAY MORNING.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
TWO TROUGHS WILL MOVE THROUGH THE REGION EARLY NEXT WEEK. RAINFALL
AMOUNTS WILL BE LIGHT BUT COULD AFFECT THE LOWER DESERTS AND POINTS
EAST OF THE COLORADO RIVER. SLIGHTLY HIGHER AMOUNTS ARE ANTICIPATED
IN THE MOUNTAINS NORTH/EAST OF PHOENIX. ANOTHER TROUGH WILL MOVE
THROUGH THE AREA ON TUESDAY AND ANY PRECIP SHOULD BE ISOLATED TO THE
MOUNTAINS AROUND GLOBE/HILLTOP/SUNFLOWER. AFTER THAT...DRY WEATHER
AND LOWER HUMIDITIES ARE EXPECTED ACROSS THE AREA. AFTERNOON
HUMIDITIES MONDAY AND TUESDAY WILL ONLY DROP INTO THE 30-50 PERCENT
RANGE WITH SLIGHTLY LOWER VALUES WEDNESDAY THROUGH FRIDAY. OVERNIGHT
RECOVERIES WILL BE GOOD. NO MAJOR WIND EVENTS EXPECTED...GENERALLY
EXPECTING LIGHT DIURNALLY DRIVEN PATTERNS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...MEYERS
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
820 PM PST Fri Jan 9 2015
.Synopsis...
Weak weather system will bring a slight chance of light showers to
the mountains of Shasta and Plumas counties late Sunday into Monday,
otherwise dry weather through next week. Chance of more widespread
precipitation next weekend.
&&
.Discussion...
Mid to high level clouds associated with elongating upper trough
along the coast will continue to spread across the area tonight as
the feature moves inland. This variable higher cloudiness will
impact fog develop in the Central Valley with visibilities likely to
bounce up and down later tonight into Saturday morning. Local WRF
and HRRR showing a few very light showers possible over the Sierra
Nevada later tonight as the trough moves through.
Another weak trough, near 135W is forecast to move through later
Saturday into early Sunday. Again, similar to the current wave, main
impact will be some mid to high level cloudiness with a slight
chance of light showers over the higher Sierra Nevada.
Strong WAA pumps upper ridge up near 135W Sunday as it progresses
towards the West Coast. Models continue to dig inside slider short
wave along leading edge of ridge across NE portions of California
late Sunday into Monday. Progs showing some light QPF possible over
the mountains of Shasta and Plumas Sunday night into Monday morning.
Dynamics then shift more crest eastward during the day Monday as the
system drops into the Great Basin.
Dry weather modeled through the remainder of the week with above
normal temperatures as high amplitude upper ridge is dominant
synoptic feature for Interior NorCal.
PCH
.Extended Discussion (Tuesday through Friday)
High amplitude upper ridge begins to strengthen over the West Coast
on Tuesday and maintain its intensity through at least Thursday.
Temperatures will be above normal during the extended forecast as
the ridge lingers over the region. The ridge will weaken slightly
Friday into the weekend. The ECMWF and GEM models suggest that
another storm system could begin to creep into Shasta county area
sometime Friday. Although, the slower GFS holds off until late
Saturday into Saturday night. We have steered more toward the ECMWF
and introduced only slight POPs for localized areas in Shasta county
region for Friday.
All models are hinting at a pattern change for late next week and
into the weekend, but models are indifferent on timing and
strength. JClapp
&&
.Aviation...
Mnly VFR conds ovr Intr NorCal nxt 24 hrs exc areas MVFR vsby in
Cntrl Vly in haze/mist with lcl IFR/LIFR poss in fog btwn 10z-18z
Sat.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1019 AM MST SAT JAN 10 2015
.UPDATE...
ISSUED AT 721 AM MST SAT JAN 10 2015
BASED ON LATEST WEB CAMS AND SFC OBS...WILL CANCEL THE DENSE FOG
ADVISORY FOR SOUTHERN EL PASO COUNTY SHORTLY. NORTHWEST WINDS ARE
SPREADING SOUTHWARD ACROSS SOUTHERN EL PASO COUNTY...AND T/TD
SPREADS ARE DROPPING. THERE COULD BE SOME PATCHY DENSE FOG ACROSS
THE FAR SOUTHERN PORTIONS OF THE AREA...BUT THINK THESE
CONDITIONS ARE TOO LOCALIZED TO WARRANT KEEPING THE HIGHLIGHT
GOING. ALSO SEEING SOME PATCHY DENSE FOG ACROSS NORTHERN PORTIONS
OF PUEBLO COUNTY (KPUB INCLUDED) AS STRATUS IS RECEDING EASTWARD.
WILL MENTION THIS THREAT IN THE GRIDS WITH SOME PATCHY DENSE FOG
THROUGH 9 AM...AND IN THE HAZARDOUS WEATHER OUTLOOK BUT CONDITIONS
DO NOT SEEM WIDESPREAD ENOUGH TO WARRANT A HIGHLIGHT. -KT
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 539 AM MST SAT JAN 10 2015
...WARMER TEMPERATURES RETURN TODAY...
CHINOOK STARTING TO BLOW AS NOTED BY WEST WINDS AT KTAD...AND
TEMPERATURES IN THE 30S ALONG THE LOWER EASTERN SLOPES OF PIKES
PEAK...WETS...AND SANGRES. WAVE CLOUDS ARE BLOCKING VIEW OF STRATUS
ACROSS PORTIONS OF EL PASO COUNTY...BUT SUSPECT THAT IT IS
ON ITS WAY OUT ACROSS NORTHERN EL PASO COUNTY BASED ON KAFF AND KMNH
OBSERVATIONS. STILL SOME DENSE FOG ACROSS SOUTHERN EL PASO COUNTY
AS OF 3 AM.
STRATUS WILL CONTINUE TO ERODE FROM WEST TO EAST THIS MORNING ACROSS
NORTHERN PORTIONS OF THE SOUTHEAST PLAINS. SUSPECT THAT DENSE FOG
ADVISORY WILL BE ABLE TO BE DROPPED BY 6 OR 7 AM...BUT HIGH RES
MODELS SEEM TO BE FASTER WITH THE CLEARING THAN WHAT IS OCCURRING SO
WILL HAVE TO SEE HOW THIS PLAYS OUT. EITHER WAY...SHOULD SEE
FOG/STRATUS BURN OFF BY LATE MORNING WITH TEMPERATURES REBOUNDING
INTO THE 40S AND 50S ACROSS THE PLAINS. BOTH HRRR AND WRF KEEP A
POCKET OF COOLER AIR ACROSS THE LOWER ARKANSAS RIVER VALLEY
(AFFECTING KLHX AND KLAA) WHERE WINDS REMAIN FAIRLY LIGHT.
MEANWHILE...WESTERLY WINDS WILL SPREAD DOWN THE LOWER EASTERN SLOPES
AND SHOULD HELP TEMPERATURES WARM INTO THE 50S. FOR THE WESTERN
PORTIONS OF THE FORECAST AREA...VALLEY FOG (ESP ACROSS THE SAN LUIS
VALLEY) SHOULD ERODE BY MID MORNING...AND TEMPERATURES SHOULD
REBOUND TO VALUES SIMILAR TO A DEGREE OR TWO WARMER THAN YESTERDAY.
NEXT SHORTWAVE ACROSS CA WILL WORK IT WAY EASTWARD THROUGH
TONIGHT...SPREADING SOME LIGHT SNOW INTO THE CONTINENTAL DIVIDE
TOWARDS SATURDAY MORNING. FORCING WITH THE SYSTEM IS WEAK...SO NOT
EXPECTING MUCH MORE THAN AN INCH ACROSS THE HIGHER MOUNTAINS BY
EARLY SUNDAY MORNING. REMAINDER OF THE FORECAST AREA WILL REMAIN
DRY. LEE TROFFING SHOULD KEEP TEMPERATURES ON THE MILD SIDE FOR THE
LOWER EASTERN SLOPES/ADJACENT PLAINS TONIGHT. COULD SEE A REPEAT OF
FOG FOR THE SAN LUIS VALLEY...THOUGH WILL BE BATTLING INVADING HIGH
CLOUDINESS WHICH MAY HINDER ITS DEVELOPMENT. SUSPECT THEIR MAY BE A
BRIEF WINDOW DURING THE LATE EVENING THROUGH THE EARLY OVERNIGHT
HOURS WHERE SOME FOG MAY DEVELOP BEFORE THE THICKER HIGH CLOUDS MOVE
IT SO GRIDS WILL CARRY PATCHY FOG FOR NOW. -KT
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 539 AM MST SAT JAN 10 2015
GENERALLY MINOR ADJUSTMENTS NEEDED FROM PREVIOUS METEOROLOGICAL
THINKING AS POPS AND TEMPERATURES CONTINUE TO BE PRIMARY LONGER
TERM METEOROLOGICAL ISSUES.
THE COMBINATION OF A RELATIVELY MINOR UPPER DISTURBANCE(SUPPORTED
BY PV ANALYSIS) WITH A NORTHERLY TO NORTHEASTERLY SURFACE
SURGE(DRIVEN BE A 1045 MB SURFACE HIGH OVER THE DAKOTAS) SUNDAY
NIGHT IS PROJECTED TO ALLOW FOR INCREASING PRECIPITATION
POTENTIAL OVER THE FORECAST DISTRICT...ESPECIALLY OVER HIGHER
TERRAIN LOCATIONS SUCH AS THE CONTINENTAL DIVIDE FROM SUNDAY INTO
MONDAY MORNING. AT THIS TIME LIGHT TO MODERATE SNOW IS ANTICIPATED
OVER PORTIONS OF THE CWFA DURING THIS TIME-FRAME.
THEN...A STRONGER UPPER LEVEL STORM SYSTEM(ONCE AGAIN INDICATED BY
PV ANALYSIS FIELDS) IS EXPECTED TO IMPACT THE CWFA FROM LATER
MONDAY INTO AT LEAST TUESDAY NIGHT AS AN UPPER DISTURBANCE
DEVELOPING OVER NORTHERN UTAH AT 00Z TUESDAY MOVES ACROSS SOUTHERN
COLORADO TUESDAY BEFORE SHIFTING INTO KANSAS BY WEDNESDAY MORNING.
THIS DISTURBANCE IN COMBINATION WITH CONTINUED COOL TO COLD MOIST
ATMOSPHERIC FLOW IS EXPECTED TO PRODUCE ANOTHER ROUND OF UNSETTLED
METEOROLOGICAL CONDITIONS DURING THIS TIME-FRAME.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR
SNOW...POSSIBLY HEAVY AT TIMES...WOULD OCCUR FROM MONDAY NIGHT
INTO TUESDAY NIGHT. WFO PUEBLO WILL CONTINUE TO MONITOR THE
DEVELOPMENT...STRENGTH AND TRACK OF THIS SYSTEM CLOSELY AND ISSUE
WINTER WEATHER HIGHLIGHTS AS WARRANTED.
A RETURN TO WARMER AND DRIER CONDITIONS SHOULD THEN BE NOTED OVER
THE FORECAST DISTRICT FROM LATER WEDNESDAY INTO FRIDAY AS
TRANSITORY UPPER RIDGING IMPACTS SOUTHERN COLORADO.
COOLEST LONGER TERM TEMPERATURES ARE ANTICIPATED FROM MONDAY INTO
WEDNESDAY MORNING WITH WARMEST READINGS PROJECTED THURSDAY AND
FRIDAY. ONCE AGAIN...BASICALLY LOW-GRADE GRADIENT WINDS SHOULD BE
NOTED OVER THE CWFA DURING THE LONGER TERM.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1016 AM MST SAT JAN 10 2015
KALS...LOW STRATUS IS IN THE PROCESS OF DISSIPATING AND SHOULD DO
SO BY 19Z WITH VFR CONDITIONS THROUGH THIS AFTERNOON. FOG AND LOW
STRATUS ARE FORECAST TO REDEVELOP THIS EVENING AND PERSIST INTO
SUNDAY MORNING.
KCOS AND KPUB...VFR CONDITIONS THROUGH THIS AFTERNOON. MID AND
HIGH LEVEL CLOUDS WILL MOVE INTO THE REGION OVERNIGHT. THERE IS
THE POSSIBILITY OF LOW STRATUS AND FOG DEVELOPING AT KPUB AFTER
03Z TONIGHT. MOZLEY
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KT
AVIATION...MOZLEY
AREA FORECAST DISCUSSION
NWS PUEBLO CO
726 AM MST SAT JAN 10 2015
.UPDATE...
ISSUED AT 721 AM MST SAT JAN 10 2015
BASED ON LATEST WEB CAMS AND SFC OBS...WILL CANCEL THE DENSE FOG
ADVISORY FOR SOUTHERN EL PASO COUNTY SHORTLY. NORTHWEST WINDS ARE
SPREADING SOUTHWARD ACROSS SOUTHERN EL PASO COUNTY...AND T/TD
SPREADS ARE DROPPING. THERE COULD BE SOME PATCHY DENSE FOG ACROSS
THE FAR SOUTHERN PORTIONS OF THE AREA...BUT THINK THESE
CONDITIONS ARE TOO LOCALIZED TO WARRANT KEEPING THE HIGHLIGHT
GOING. ALSO SEEING SOME PATCHY DENSE FOG ACROSS NORTHERN PORTIONS
OF PUEBLO COUNTY (KPUB INCLUDED) AS STRATUS IS RECEDING EASTWARD.
WILL MENTION THIS THREAT IN THE GRIDS WITH SOME PATCHY DENSE FOG
THROUGH 9 AM...AND IN THE HAZARDOUS WEATHER OUTLOOK BUT CONDITIONS
DO NOT SEEM WIDESPREAD ENOUGH TO WARRANT A HIGHLIGHT. -KT
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 539 AM MST SAT JAN 10 2015
...WARMER TEMPERATURES RETURN TODAY...
CHINOOK STARTING TO BLOW AS NOTED BY WEST WINDS AT KTAD...AND
TEMPERATURES IN THE 30S ALONG THE LOWER EASTERN SLOPES OF PIKES
PEAK...WETS...AND SANGRES. WAVE CLOUDS ARE BLOCKING VIEW OF STRATUS
ACROSS PORTIONS OF EL PASO COUNTY...BUT SUSPECT THAT IT IS
ON ITS WAY OUT ACROSS NORTHERN EL PASO COUNTY BASED ON KAFF AND KMNH
OBSERVATIONS. STILL SOME DENSE FOG ACROSS SOUTHERN EL PASO COUNTY
AS OF 3 AM.
STRATUS WILL CONTINUE TO ERODE FROM WEST TO EAST THIS MORNING ACROSS
NORTHERN PORTIONS OF THE SOUTHEAST PLAINS. SUSPECT THAT DENSE FOG
ADVISORY WILL BE ABLE TO BE DROPPED BY 6 OR 7 AM...BUT HIGH RES
MODELS SEEM TO BE FASTER WITH THE CLEARING THAN WHAT IS OCCURRING SO
WILL HAVE TO SEE HOW THIS PLAYS OUT. EITHER WAY...SHOULD SEE
FOG/STRATUS BURN OFF BY LATE MORNING WITH TEMPERATURES REBOUNDING
INTO THE 40S AND 50S ACROSS THE PLAINS. BOTH HRRR AND WRF KEEP A
POCKET OF COOLER AIR ACROSS THE LOWER ARKANSAS RIVER VALLEY
(AFFECTING KLHX AND KLAA) WHERE WINDS REMAIN FAIRLY LIGHT.
MEANWHILE...WESTERLY WINDS WILL SPREAD DOWN THE LOWER EASTERN SLOPES
AND SHOULD HELP TEMPERATURES WARM INTO THE 50S. FOR THE WESTERN
PORTIONS OF THE FORECAST AREA...VALLEY FOG (ESP ACROSS THE SAN LUIS
VALLEY) SHOULD ERODE BY MID MORNING...AND TEMPERATURES SHOULD
REBOUND TO VALUES SIMILAR TO A DEGREE OR TWO WARMER THAN YESTERDAY.
NEXT SHORTWAVE ACROSS CA WILL WORK IT WAY EASTWARD THROUGH
TONIGHT...SPREADING SOME LIGHT SNOW INTO THE CONTINENTAL DIVIDE
TOWARDS SATURDAY MORNING. FORCING WITH THE SYSTEM IS WEAK...SO NOT
EXPECTING MUCH MORE THAN AN INCH ACROSS THE HIGHER MOUNTAINS BY
EARLY SUNDAY MORNING. REMAINDER OF THE FORECAST AREA WILL REMAIN
DRY. LEE TROFFING SHOULD KEEP TEMPERATURES ON THE MILD SIDE FOR THE
LOWER EASTERN SLOPES/ADJACENT PLAINS TONIGHT. COULD SEE A REPEAT OF
FOG FOR THE SAN LUIS VALLEY...THOUGH WILL BE BATTLING INVADING HIGH
CLOUDINESS WHICH MAY HINDER ITS DEVELOPMENT. SUSPECT THEIR MAY BE A
BRIEF WINDOW DURING THE LATE EVENING THROUGH THE EARLY OVERNIGHT
HOURS WHERE SOME FOG MAY DEVELOP BEFORE THE THICKER HIGH CLOUDS MOVE
IT SO GRIDS WILL CARRY PATCHY FOG FOR NOW. -KT
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 539 AM MST SAT JAN 10 2015
GENERALLY MINOR ADJUSTMENTS NEEDED FROM PREVIOUS METEOROLOGICAL
THINKING AS POPS AND TEMPERATURES CONTINUE TO BE PRIMARY LONGER
TERM METEOROLOGICAL ISSUES.
THE COMBINATION OF A RELATIVELY MINOR UPPER DISTURBANCE(SUPPORTED
BY PV ANALYSIS) WITH A NORTHERLY TO NORTHEASTERLY SURFACE
SURGE(DRIVEN BE A 1045 MB SURFACE HIGH OVER THE DAKOTAS) SUNDAY
NIGHT IS PROJECTED TO ALLOW FOR INCREASING PRECIPITATION
POTENTIAL OVER THE FORECAST DISTRICT...ESPECIALLY OVER HIGHER
TERRAIN LOCATIONS SUCH AS THE CONTINENTAL DIVIDE FROM SUNDAY INTO
MONDAY MORNING. AT THIS TIME LIGHT TO MODERATE SNOW IS ANTICIPATED
OVER PORTIONS OF THE CWFA DURING THIS TIME-FRAME.
THEN...A STRONGER UPPER LEVEL STORM SYSTEM(ONCE AGAIN INDICATED BY
PV ANALYSIS FIELDS) IS EXPECTED TO IMPACT THE CWFA FROM LATER
MONDAY INTO AT LEAST TUESDAY NIGHT AS AN UPPER DISTURBANCE
DEVELOPING OVER NORTHERN UTAH AT 00Z TUESDAY MOVES ACROSS SOUTHERN
COLORADO TUESDAY BEFORE SHIFTING INTO KANSAS BY WEDNESDAY MORNING.
THIS DISTURBANCE IN COMBINATION WITH CONTINUED COOL TO COLD MOIST
ATMOSPHERIC FLOW IS EXPECTED TO PRODUCE ANOTHER ROUND OF UNSETTLED
METEOROLOGICAL CONDITIONS DURING THIS TIME-FRAME.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR
SNOW...POSSIBLY HEAVY AT TIMES...WOULD OCCUR FROM MONDAY NIGHT
INTO TUESDAY NIGHT. WFO PUEBLO WILL CONTINUE TO MONITOR THE
DEVELOPMENT...STRENGTH AND TRACK OF THIS SYSTEM CLOSELY AND ISSUE
WINTER WEATHER HIGHLIGHTS AS WARRANTED.
A RETURN TO WARMER AND DRIER CONDITIONS SHOULD THEN BE NOTED OVER
THE FORECAST DISTRICT FROM LATER WEDNESDAY INTO FRIDAY AS
TRANSITORY UPPER RIDGING IMPACTS SOUTHERN COLORADO.
COOLEST LONGER TERM TEMPERATURES ARE ANTICIPATED FROM MONDAY INTO
WEDNESDAY MORNING WITH WARMEST READINGS PROJECTED THURSDAY AND
FRIDAY. ONCE AGAIN...BASICALLY LOW-GRADE GRADIENT WINDS SHOULD BE
NOTED OVER THE CWFA DURING THE LONGER TERM.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 539 AM MST SAT JAN 10 2015
LIFR/IFR STRATUS/FOG WILL ERODE FROM WEST TO EAST ACROSS THE I-25
CORRIDOR AS WESTERLY WINDS SPREAD OFF THE MOUNTAINS INTO THE
ADJACENT PLAINS. SHOULD SEE STRATUS CLEAR BOTH KCOS AND KPUB BY 16Z
IF NOT SOONER AT KCOS. MEANWHILE...LIFR CONDITIONS AT KALS SHOULD
BREAK BY 16Z. WINDS WILL BE LIGHT TODAY AT THE TERMINALS WITH VFR
CONDITIONS EXPECTED INTO TONIGHT. COULD SEE SOME IFR CIGS/VIS
RETURN AT KALS LATE THIS EVENING...THOUGH THIS WILL BE DETERMINED BY
THE TIMING OF CLOUDS MOVING IN FROM THE WEST ASSOCIATED WITH A WEAK
WEATHER SYSTEM WHICH WILL BRING SNOW TO THE CONTDVD LATE TONIGHT
INTO SUNDAY. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
539 AM MST SAT JAN 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 539 AM MST SAT JAN 10 2015
...WARMER TEMPERATURES RETURN TODAY...
CHINOOK STARTING TO BLOW AS NOTED BY WEST WINDS AT KTAD...AND
TEMPERATURES IN THE 30S ALONG THE LOWER EASTERN SLOPES OF PIKES
PEAK...WETS...AND SANGRES. WAVE CLOUDS ARE BLOCKING VIEW OF STRATUS
ACROSS PORTIONS OF EL PASO COUNTY...BUT SUSPECT THAT IT IS
ON ITS WAY OUT ACROSS NORTHERN EL PASO COUNTY BASED ON KAFF AND KMNH
OBSERVATIONS. STILL SOME DENSE FOG ACROSS SOUTHERN EL PASO COUNTY
AS OF 3 AM.
STRATUS WILL CONTINUE TO ERODE FROM WEST TO EAST THIS MORNING ACROSS
NORTHERN PORTIONS OF THE SOUTHEAST PLAINS. SUSPECT THAT DENSE FOG
ADVISORY WILL BE ABLE TO BE DROPPED BY 6 OR 7 AM...BUT HIGH RES
MODELS SEEM TO BE FASTER WITH THE CLEARING THAN WHAT IS OCCURRING SO
WILL HAVE TO SEE HOW THIS PLAYS OUT. EITHER WAY...SHOULD SEE
FOG/STRATUS BURN OFF BY LATE MORNING WITH TEMPERATURES REBOUNDING
INTO THE 40S AND 50S ACROSS THE PLAINS. BOTH HRRR AND WRF KEEP A
POCKET OF COOLER AIR ACROSS THE LOWER ARKANSAS RIVER VALLEY
(AFFECTING KLHX AND KLAA) WHERE WINDS REMAIN FAIRLY LIGHT.
MEANWHILE...WESTERLY WINDS WILL SPREAD DOWN THE LOWER EASTERN SLOPES
AND SHOULD HELP TEMPERATURES WARM INTO THE 50S. FOR THE WESTERN
PORTIONS OF THE FORECAST AREA...VALLEY FOG (ESP ACROSS THE SAN LUIS
VALLEY) SHOULD ERODE BY MID MORNING...AND TEMPERATURES SHOULD
REBOUND TO VALUES SIMILAR TO A DEGREE OR TWO WARMER THAN YESTERDAY.
NEXT SHORTWAVE ACROSS CA WILL WORK IT WAY EASTWARD THROUGH
TONIGHT...SPREADING SOME LIGHT SNOW INTO THE CONTINENTAL DIVIDE
TOWARDS SATURDAY MORNING. FORCING WITH THE SYSTEM IS WEAK...SO NOT
EXPECTING MUCH MORE THAN AN INCH ACROSS THE HIGHER MOUNTAINS BY
EARLY SUNDAY MORNING. REMAINDER OF THE FORECAST AREA WILL REMAIN
DRY. LEE TROFFING SHOULD KEEP TEMPERATURES ON THE MILD SIDE FOR THE
LOWER EASTERN SLOPES/ADJACENT PLAINS TONIGHT. COULD SEE A REPEAT OF
FOG FOR THE SAN LUIS VALLEY...THOUGH WILL BE BATTLING INVADING HIGH
CLOUDINESS WHICH MAY HINDER ITS DEVELOPMENT. SUSPECT THEIR MAY BE A
BRIEF WINDOW DURING THE LATE EVENING THROUGH THE EARLY OVERNIGHT
HOURS WHERE SOME FOG MAY DEVELOP BEFORE THE THICKER HIGH CLOUDS MOVE
IT SO GRIDS WILL CARRY PATCHY FOG FOR NOW. -KT
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 539 AM MST SAT JAN 10 2015
GENERALLY MINOR ADJUSTMENTS NEEDED FROM PREVIOUS METEOROLOGICAL
THINKING AS POPS AND TEMPERATURES CONTINUE TO BE PRIMARY LONGER
TERM METEOROLOGICAL ISSUES.
THE COMBINATION OF A RELATIVELY MINOR UPPER DISTURBANCE(SUPPORTED
BY PV ANALYSIS) WITH A NORTHERLY TO NORTHEASTERLY SURFACE
SURGE(DRIVEN BE A 1045 MB SURFACE HIGH OVER THE DAKOTAS) SUNDAY
NIGHT IS PROJECTED TO ALLOW FOR INCREASING PRECIPITATION
POTENTIAL OVER THE FORECAST DISTRICT...ESPECIALLY OVER HIGHER
TERRAIN LOCATIONS SUCH AS THE CONTINENTAL DIVIDE FROM SUNDAY INTO
MONDAY MORNING. AT THIS TIME LIGHT TO MODERATE SNOW IS ANTICIPATED
OVER PORTIONS OF THE CWFA DURING THIS TIME-FRAME.
THEN...A STRONGER UPPER LEVEL STORM SYSTEM(ONCE AGAIN INDICATED BY
PV ANALYSIS FIELDS) IS EXPECTED TO IMPACT THE CWFA FROM LATER
MONDAY INTO AT LEAST TUESDAY NIGHT AS AN UPPER DISTURBANCE
DEVELOPING OVER NORTHERN UTAH AT 00Z TUESDAY MOVES ACROSS SOUTHERN
COLORADO TUESDAY BEFORE SHIFTING INTO KANSAS BY WEDNESDAY MORNING.
THIS DISTURBANCE IN COMBINATION WITH CONTINUED COOL TO COLD MOIST
ATMOSPHERIC FLOW IS EXPECTED TO PRODUCE ANOTHER ROUND OF UNSETTLED
METEOROLOGICAL CONDITIONS DURING THIS TIME-FRAME.
AT THIS TIME...IT APPEARS THAT THE HIGHEST POTENTIAL FOR
SNOW...POSSIBLY HEAVY AT TIMES...WOULD OCCUR FROM MONDAY NIGHT
INTO TUESDAY NIGHT. WFO PUEBLO WILL CONTINUE TO MONITOR THE
DEVELOPMENT...STRENGTH AND TRACK OF THIS SYSTEM CLOSELY AND ISSUE
WINTER WEATHER HIGHLIGHTS AS WARRANTED.
A RETURN TO WARMER AND DRIER CONDITIONS SHOULD THEN BE NOTED OVER
THE FORECAST DISTRICT FROM LATER WEDNESDAY INTO FRIDAY AS
TRANSITORY UPPER RIDGING IMPACTS SOUTHERN COLORADO.
COOLEST LONGER TERM TEMPERATURES ARE ANTICIPATED FROM MONDAY INTO
WEDNESDAY MORNING WITH WARMEST READINGS PROJECTED THURSDAY AND
FRIDAY. ONCE AGAIN...BASICALLY LOW-GRADE GRADIENT WINDS SHOULD BE
NOTED OVER THE CWFA DURING THE LONGER TERM.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 539 AM MST SAT JAN 10 2015
LIFR/IFR STRATUS/FOG WILL ERODE FROM WEST TO EAST ACROSS THE I-25
CORRIDOR AS WESTERLY WINDS SPREAD OFF THE MOUNTAINS INTO THE
ADJACENT PLAINS. SHOULD SEE STRATUS CLEAR BOTH KCOS AND KPUB BY 16Z
IF NOT SOONER AT KCOS. MEANWHILE...LIFR CONDITIONS AT KALS SHOULD
BREAK BY 16Z. WINDS WILL BE LIGHT TODAY AT THE TERMINALS WITH VFR
CONDITIONS EXPECTED INTO TONIGHT. COULD SEE SOME IFR CIGS/VIS
RETURN AT KALS LATE THIS EVENING...THOUGH THIS WILL BE DETERMINED BY
THE TIMING OF CLOUDS MOVING IN FROM THE WEST ASSOCIATED WITH A WEAK
WEATHER SYSTEM WHICH WILL BRING SNOW TO THE CONTDVD LATE TONIGHT
INTO SUNDAY. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM MST THIS MORNING FOR COZ085.
&&
$$
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NWS KEY WEST FL
1027 PM EST SUN JAN 11 2015
.DISCUSSION...
.CURRENTLY...
SURFACE WINDS ALONG THE ISLANDS ARE GENERALLY EASTERLY 10 KNOTS OR
LESS...WHILE CMAN STATIONS ALONG THE REEF ARE RUNNING FROM 13 TO 19
KNOTS. HOWEVER...WINDS IN THE EVENING SOUNDING AND KBYX VWP FOR THE
LOWEST FEW KILOMETERS ARE 20 KNOTS PLUS...SO THERE DOES APPEAR TO BE
SOME BOUNDARY LAYER DECOUPLING. A FEW LOW TOP SHOWERS HAVE BEGUN TO
SPRING UP IN THE FLORIDA STRAITS WELL OUTSIDE THE REEF.
OTHERWISE...FAIRLY CLEAR SKIES OVERHEAD.
.SHORT TERM...
BOTH THE LOCALLY RUN WRF AND THE HRRR MODELS DEVELOP SCATTERED
SHOWERS ALONG A WIND SURGE OVERNIGHT. ALTHOUGH THAT DOES NOT YET
APPEAR TO BE MATERIALIZING...OUTSIDE OF SHOWERS DEVELOPING IN THE
STRAITS...THERE IS STILL SUFFICIENT CONFIDENCE THIS WILL OCCUR.
THEREFORE WILL LEAVE THE CHANCE POPS OVERNIGHT AND NOT SIGNIFICANTLY
ALTER THE MARINE FORECAST. WILL LEAVE THE SMALL CRAFT ADVISORY IN
EFFECT FOR THE EVENING UPDATE.
&&
.MARINE...
A SMALL CRAFT ADVISORY IS IN EFFECT OVERNIGHT FOR THE FLORIDA STRAITS
WATERS OUTSIDE THE REEF...AS WELL AS THE WATERS OF HAWK CHANNEL ALONG
THE MIDDLE AND UPPER KEYS. WINDS NEAR 20 KNOTS ARE EXPECTED OVER
THESE WATERS. WINDS WILL BE DECREASING TO EASTERLY 15 TO 20 KNOTS
TOMORROW AND DOWN TO 10 TO 15 KNOTS BY MONDAY NIGHT. THERE`S A CHANCE
OF SHOWERS AND THUNDERSTORMS OVERNIGHT IN THESE WATERS. IN THE GULF
AND BAY WATERS...WINDS NEAR 15 KNOTS CAN BE EXPECTED
OVERNIGHT...DECREASING MONDAY AND MONDAY EVENING.
&&
.AVIATION...
UNTIL 15Z/12TH...EXPECT SHOWERS TO PROLIFERATE ALONG WITH SEVERAL
MVFR EPISODES AT THE KEY WEST AND MARATHON
TERMINALS...OTHERWISE...VFR CONDITIONS WILL PREVAIL. AWAY FROM
SHOWERS...MOSTLY EAST WINDS WILL INCREASE TO BETWEEN 8 AND 12 KNOTS.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 5 AM EST MONDAY FOR GMZ042-043-052>055-
072>075.
&&
$$
PUBLIC/MARINE.........DEVANAS
AVIATION/NOWCASTS.....APA
DATA COLLECTION.......VICKERY
VISIT US ON THE WEB AT WEATHER.GOV/KEY
FOLLOW US ON FACEBOOK AND TWITTER AT...
WWW.FACEBOOK.COM/NWSKEYWEST
WWW.TWITTER.COM/NWSKEYWEST
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1015 PM EST SUN JAN 11 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 234 PM EST SUN JAN 11 2015
A FRONTAL SYSTEM IS EXPECTED TO PASS OVER THE AREA TONIGHT INTO
MONDAY MORNING. IN THE WAKE OF THIS FRONT...A LARGE HIGH PRESSURE
SYSTEM WILL MOVE INTO THE AREA FOR THE REST OF NEXT WEEK.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 1015 PM EST SUN JAN 11 2015
ANOTHER ROUND OF PRECIPITATION IS MOVING INTO CENTRAL INDIANA AT THE
MOMENT. WIDESPREAD PRECIPITATION WILL CONTINUE INTO THE EARLY
OVERNIGHT AS ISENTROPIC LIFT CONTINUES. THUS CONTINUED CATEGORICAL
POPS THROUGH 08Z. FORCING BEGINS TO WEAKEN AFTER THAT...SO DECREASED
POPS SOME AFTER 08Z.
PRECIPITATION HAS BEEN MAINLY FREEZING RAIN ACROSS MUCH OF THE AREA
WITH WARM TEMPERATURES ALOFT. THIS WARM AIR ALOFT REMAINS IN PLACE
INTO THE EARLY OVERNIGHT SO CONTINUED WITH FREEZING RAIN AS THE MAIN
PRECIPITATION TYPE MOST AREAS. LATEST HI RES MODELS SHOW COLDER AIR
WORKING IN FROM THE NORTHWEST LATER IN THE NIGHT...WHICH WILL BEGIN
TO CHANGE PRECIP INTO SNOW. PREVIOUS FORECAST HAD THIS TREND COVERED
SO DIDN/T CHANGE PRECIPITATION TYPE TREND.
MOST OF THE FORECAST AREA REMAINS AT FREEZING OR BELOW AND THIS
SHOULD CONTINUE. FAR SOUTHERN AREAS HAVE CREPT UP TO ABOVE FREEZING
AND WILL DO SO AT TIMES...ALLOWING PRECIPITATION TO BE RAIN AT
TIMES. HOWEVER...IN THE HILLY TERRAIN...WOULD NOT RULE OUT SOME LOW
LYING AREAS REMAINING BELOW FREEZING AND STILL EXPERIENCING FREEZING
RAIN.
PLENTY OF REPORTS OF ICE FROM AROUND CENTRAL INDIANA SO FAR TONIGHT.
SECONDARY ROADS ARE BECOMING SLICK...AND SOME MAIN ROADS ACROSS THE
NORTH ARE SLICK.
CONDITIONS IN SOME PARTS OF THE NORTHERN ADVISORY AREA HAVE
APPROACHED ICE STORM CRITERIA...BUT BULK OF ADDITIONAL PRECIPITATION
LOOKS TO REMAIN SOUTH OF THESE AREAS. ON THE FAR SOUTHERN END OF THE
ADVISORY...AS MENTIONED ABOVE FEEL THAT ALTHOUGH SOME AREAS WILL BE
RAIN OTHERS COULD STILL EXPERIENCE FREEZING RAIN MAKING ROADS SLICK.
AREAS IN THE ICE STORM WARNING STILL LOOK GOOD TO REACH
CRITERIA...EVEN THOUGH SOME MAIN ROADS MAY NOT FEEL AS MUCH IMPACT.
HOWEVER...EVEN A SLIGHT COOLDOWN COULD CAUSE RAPID ACCRETION ON THE
MAIN ROADS.
GIVEN ALL THE ABOVE DECIDED TO LEAVE HEADLINES AS IS. SOME NORTHERN
AREAS NEAR THE ICE STORM WARNING COUNTIES COULD GET TO ICE STORM
CRITERIA...BUT AM NOT CONFIDENT ENOUGH TO ADD ANY COUNTIES TO THE
WARNING.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 234 PM EST SUN JAN 11 2015
WILL KEEP POPS RATHER HIGH ACROSS THE AREA THROUGH THE MORNING HOURS
ON MONDAY AS THERE STILL SOME LIFT AROUND AT THAT TIME. AS COLD AIR
ADVECTS INTO THE AREA...PRECIPITATION SHOULD TREND TOWARDS ALL SNOW.
ANY ADDITIONAL ACCUMULATIONS OF SNOW OR ICE SHOULD BE LIGHT AS LIFT
TAPERS OFF.
AFTER MONDAY...THE REST OF THE SHORT TERM LOOKS QUIET AS A LARGE
SURFACE HIGH MOVES INTO THE AREA.
QUICK LOOK AT LOW LEVEL THICKNESS PROGS SUGGEST THE GFS MOS MAY BE
TOO WARM WITH THE LOWS MONDAY NIGHT...OTHERWISE THE GUIDANCE LOOKS
GOOD.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EST SUN JAN 11 2015
DRY WEATHER WITH WARMING TEMPERATURES IN STORE FOR THE LONG TERM.
DETERMINISTIC MODELS WAYS APART WITH UPPER SYSTEM NEXT WEEK...BUT
ALL HAVE DEEPER MOISTURE AND QPF WELL TO OUR NORTH.
TEMPERATURES WILL START OFF BELOW NORMAL WITH SURFACE HIGH PRESSURE
FROM THE SOUTHERN PLAINS TO THE OHIO IN THE WAKE OF THE ARCTIC
FRONT. BY WEEKEND THE HIGH PRESSURE RIDGE WILL BE FROM THE
SOUTHEASTERN STATES NORTHEAST ACROSS THE ATLANTIC. THIS WILL DRAW
SOUTHERLY FLOW AND WARMER TEMPERATURES TO CENTRAL INDIANA. 12Z
SUPERBLEND HAS THE RIGHT IDEA REGARDING TRENDS WITH AFTERNOON HIGHS
ONLY IN THE 20S AND 30S ON THURSDAY TO MOSTLY THE 40S BY SUNDAY.
&&
.AVIATION /DISCUSSION FOR 120300Z TAF UPDATE/...
ISSUED AT 916 PM EST SUN JAN 11 2015
STEADY PRECIP FALLING IN THE I-70 CORRIDOR CURRENTLY...FALLING AS
FREEZING RAIN AT KIND. TEMPS HAVE WARMED SLIGHTLY AT KHUF WHERE THEY
HAVE ALTERNATED AS FREEZING RAIN AND RAIN. PRECIP ALSO HAS
TRANSITIONED TO LIGHT RAIN AT KBMG. RAP SURFACE TEMP PLOTS SHOWING
POTENTIAL FOR TEMPS TO REMAIN JUST ABOVE FREEZING AT KBMG FOR THE
NEXT SEVERAL HOURS...BUT SHOULD HOLD IN THE 31-32 RANGE ALONG THE
I-70 CORRIDOR. MADE TWEAKS TO ALL TERMINALS BASED ON CURRENT OBS AND
EXPECTATIONS FOR NEXT FEW HOURS...BUT PREDOMINANT PRECIP TYPE SHOULD
REMAINS FZRA AT KIND AND KHUF.
00Z DISCUSSION FOLLOWS.
VERY POOR FLYING CONDITIONS OVERNIGHT INTO MONDAY MORNING AS
COMPLEX WINTER STORM IMPACTS CENTRAL INDIANA.
PRECIP TYPE AND AIR TEMPERATURE ARE THE CRITICAL FACTORS FOR THE
TERMINALS OVER THE NEXT 6-9 HOURS PARTICULARLY AS PRECIPITATION
OVERSPREADS THE REGION. AIR TEMPS HAD WARMED INTO THE 33 TO 35
RANGE AT KBMG/KHUF/KIND EARLIER BUT AS EVAPORATIVE COLLING
PROCESSES HAVE TAKEN OVER WITH THE MOISTENING OF THE LOWER
LEVELS...HAVE SEEN THOSE TEMPS SLIP BACK TO RIGHT AROUND 32F.
CURRENT RAP/HRRR BOTH HINT AT AIR TEMPS HOVERING IN THAT 30 TO 32
RANGE INTO THE OVERNIGHT AT KHUF AND KIND WHERE HAVE STRONG
CONCERNS THAT FREEZING RAIN WILL BE THE PREDOMINANT PRECIP TYPE
THROUGH 06-08Z. HAVE MAINTAINED A PERIOD OF MODERATE FREEZING RAIN
FOR ABOUT 4 HOURS TO ACCOUNT WHEN HEAVIEST PRECIPITATION IS
EXPECTED TO FALL. AT KLAF...WARMER BOUNDARY LAYER AIR HAS HELPED
SWITCH PRECIP TO FREEZING RAIN AND EXPECT IT TO REMAIN SO THROUGH
THE EVENING BEFORE SLEET BEGINS TO MIX BACK IN AFTER MIDNIGHT.
KBMG MAY END UP BEING THE MOST CHALLENGING OF THE SITES. KBMG IS
REPORTING UP AT THE MOMENT AND 32F...BUT ALL SHORT RANGE MODEL
GUIDANCE BRINGS SLIGHTLY WARMER AIR TEMPERATURES BACK INTO THE
AREA DURING THE EVENING AND EARLY OVERNIGHT. WILL MAINTAIN -FZRA
AS THE PREDOMINANT PRECIP TYPE...BUT HAVE INTRODUCED A TEMPO GROUP
FROM 02-06Z FOR RAIN TO ACCOUNT FOR THE EXPECTED WARMER TEMPS. IFR
AND LOWER CONDITIONS WILL DEVELOP OVERNIGHT AS WELL.
AS COLDER AIR BEGINS TO SPREAD BACK SOUTH LATE TONIGHT AND EARLY
MONDAY...WILL BEGIN TO SEE PL MIX IN AFTER 07-08Z...THEN
EVENTUALLY A CHANGEOVER TO -SN FROM NORTH TO SOUTH BEGINNING
AROUND 09Z AT KLAF...AND SHORTLY AFTER DAYBREAK AT KHUF AND KIND.
SNOW SHOWERS WILL END BY EARLY AFTERNOON AS THE DEEPER MOISTURE
SHIFTS EAST. CEILINGS WILL SLOWLY LIFT BACK UP TO AROUND 1500FT
WITH SOME CLEARING LATE AS DRIER AIR BUILDS IN. IT WILL BECOME
GUSTY AS WELL...WITH NORTHERLY WINDS GUSTING TO 20-25KTS.
EXPECT UPDATES THROUGH THE EVENING AS THIS FLUID WINTER STORM
EVOLVES. CANNOT STRESS ENOUGH THAT ONE DEGREE AND A MATTER OF
MILES CAN MAKE ALL THE DIFFERENCE IN PRECIP TYPE. AS STATED
ABOVE...ICING IS POSSIBLE AT ALL TERMINALS BUT GREATEST CONCERNS
REMAIN AT KHUF AND KIND WHERE POTENTIAL FOR UP TO A QUARTER INCH OF
ICE ACCUM EXISTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 AM TO 1 PM EST MONDAY FOR INZ037-
039>042-045>049-051>057.
ICE STORM WARNING UNTIL 7 AM EST MONDAY FOR INZ037-039>042-
045>049-051>057.
WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR INZ021-028>031-
035-036-038-043-044-060>065-067>072.
&&
$$
SYNOPSIS...JAS
NEAR TERM...50
SHORT TERM...JAS
LONG TERM...NIELD
AVIATION...RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
916 PM EST SUN JAN 11 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 234 PM EST SUN JAN 11 2015
A FRONTAL SYSTEM IS EXPECTED TO PASS OVER THE AREA TONIGHT INTO
MONDAY MORNING. IN THE WAKE OF THIS FRONT...A LARGE HIGH PRESSURE
SYSTEM WILL MOVE INTO THE AREA FOR THE REST OF NEXT WEEK.
&&
.NEAR TERM /REST OF THIS AFTERNOON AND TONIGHT/...
ISSUED AT 234 PM EST SUN JAN 11 2015
RADAR INDICATES LIGHT PRECIPITATION STARTING TO DEVELOP ACROSS THE
AREA AS INITIAL BAND OF LIFT MOVES THROUGH. SURFACE REPORTS INDICATE
PRECIPITATION IS MIXED...RANGING FROM LIGHT SNOW...SLEET...FREEZING
RAIN...AND LIGHT RAIN. STRONGER LIFT IS PROGGED TO BEGIN MOVING INTO
THE AREA AFTER 112200Z...SO EXPECTING PRECIPITATION TO BECOME MORE
WIDESPREAD TOWARDS EVENING. SURFACE WET BULBS ARE HOVERING AROUND 30
DEGREES FOR THE MOST PART...SO SURFACE TEMPERATURES WILL PROBABLY
COOL A FEW DEGREES ONCE THE STEADIER PRECIPITATION STARTS.
WARM ADVECTION ALOFT LOOKED PRETTY STRONG BASED ON THIS MORNING/S
UPPER AIR...SO SUSPECT ONLY ABOUT THE NORTHERN THIRD OF THE FORECAST
AREA WILL SEE ANY PROLONGED PERIODS OF SLEET OR SNOW TONIGHT.
FARTHER SOUTH...APPEARS PRECIPITATION TYPES WILL MAINLY BE FREEZING
RAIN OR RAIN. WHERE SURFACE FREEZING LINE WILL END UP TONIGHT
DIFFICULT TO PREDICT WITH WARM ADVECTION AND EVAPORATIVE
COOLING...BUT PROGGED WET BULBS SUGGESTS THE SOUTHERN THIRD TO HALF
OF THE FORECAST AREA MAY RISE ABOVE FREEZING TONIGHT. PINNING DOWN
EXACTLY WHERE THE FREEZING LINE WILL SET UP WILL COME DOWN TO
NOWCASTING TO SEE HOW TEMPERATURES ACTUALLY BEHAVE ONCE THE STEADIER
PRECIPITATION STARTS.
APPEARS WARM ADVECTION WILL PROBABLY CONTINUE INTO THE EARLY MORNING
HOURS OF MONDAY BEFORE CUTTING OFF...SO PRECIPITATION TYPE TRENDS
MAY TEND TO REVERSE ITSELF AS DAYBREAK APPROACHES.
WILL LET THE CURRENT HEADLINES RIDE AS IS GIVEN THE FACT THAT THE
EVENT IS JUST GETTING STARTED...HOWEVER BASED ON HOW THE WET BULBS
ARE TRENDING...THE MAIN ICE THREAT MAY BE A LITTLE NORTH OF WHAT THE
EARLIER FORECASTS INDICATED...ALONG WITH LOWER SNOW ACCUMULATIONS.
THINK TEMPERATURES WILL HOLD ONCE THE STEADIER PRECIPITATION GETS
GOING.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 234 PM EST SUN JAN 11 2015
WILL KEEP POPS RATHER HIGH ACROSS THE AREA THROUGH THE MORNING HOURS
ON MONDAY AS THERE STILL SOME LIFT AROUND AT THAT TIME. AS COLD AIR
ADVECTS INTO THE AREA...PRECIPITATION SHOULD TREND TOWARDS ALL SNOW.
ANY ADDITIONAL ACCUMULATIONS OF SNOW OR ICE SHOULD BE LIGHT AS LIFT
TAPERS OFF.
AFTER MONDAY...THE REST OF THE SHORT TERM LOOKS QUIET AS A LARGE
SURFACE HIGH MOVES INTO THE AREA.
QUICK LOOK AT LOW LEVEL THICKNESS PROGS SUGGEST THE GFS MOS MAY BE
TOO WARM WITH THE LOWS MONDAY NIGHT...OTHERWISE THE GUIDANCE LOOKS
GOOD.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 224 PM EST SUN JAN 11 2015
DRY WEATHER WITH WARMING TEMPERATURES IN STORE FOR THE LONG TERM.
DETERMINISTIC MODELS WAYS APART WITH UPPER SYSTEM NEXT WEEK...BUT
ALL HAVE DEEPER MOISTURE AND QPF WELL TO OUR NORTH.
TEMPERATURES WILL START OFF BELOW NORMAL WITH SURFACE HIGH PRESSURE
FROM THE SOUTHERN PLAINS TO THE OHIO IN THE WAKE OF THE ARCTIC
FRONT. BY WEEKEND THE HIGH PRESSURE RIDGE WILL BE FROM THE
SOUTHEASTERN STATES NORTHEAST ACROSS THE ATLANTIC. THIS WILL DRAW
SOUTHERLY FLOW AND WARMER TEMPERATURES TO CENTRAL INDIANA. 12Z
SUPERBLEND HAS THE RIGHT IDEA REGARDING TRENDS WITH AFTERNOON HIGHS
ONLY IN THE 20S AND 30S ON THURSDAY TO MOSTLY THE 40S BY SUNDAY.
&&
.AVIATION /DISCUSSION FOR 120300Z TAF UPDATE/...
ISSUED AT 916 PM EST SUN JAN 11 2015
STEADY PRECIP FALLING IN THE I-70 CORRIDOR CURRENTLY...FALLING AS
FREEZING RAIN AT KIND. TEMPS HAVE WARMED SLIGHTLY AT KHUF WHERE THEY
HAVE ALTERNATED AS FREEZING RAIN AND RAIN. PRECIP ALSO HAS
TRANSITIONED TO LIGHT RAIN AT KBMG. RAP SURFACE TEMP PLOTS SHOWING
POTENTIAL FOR TEMPS TO REMAIN JUST ABOVE FREEZING AT KBMG FOR THE
NEXT SEVERAL HOURS...BUT SHOULD HOLD IN THE 31-32 RANGE ALONG THE
I-70 CORRIDOR. MADE TWEAKS TO ALL TERMINALS BASED ON CURRENT OBS AND
EXPECTATIONS FOR NEXT FEW HOURS...BUT PREDOMINANT PRECIP TYPE SHOULD
REMAINS FZRA AT KIND AND KHUF.
00Z DISCUSSION FOLLOWS.
VERY POOR FLYING CONDITIONS OVERNIGHT INTO MONDAY MORNING AS
COMPLEX WINTER STORM IMPACTS CENTRAL INDIANA.
PRECIP TYPE AND AIR TEMPERATURE ARE THE CRITICAL FACTORS FOR THE
TERMINALS OVER THE NEXT 6-9 HOURS PARTICULARLY AS PRECIPITATION
OVERSPREADS THE REGION. AIR TEMPS HAD WARMED INTO THE 33 TO 35
RANGE AT KBMG/KHUF/KIND EARLIER BUT AS EVAPORATIVE COLLING
PROCESSES HAVE TAKEN OVER WITH THE MOISTENING OF THE LOWER
LEVELS...HAVE SEEN THOSE TEMPS SLIP BACK TO RIGHT AROUND 32F.
CURRENT RAP/HRRR BOTH HINT AT AIR TEMPS HOVERING IN THAT 30 TO 32
RANGE INTO THE OVERNIGHT AT KHUF AND KIND WHERE HAVE STRONG
CONCERNS THAT FREEZING RAIN WILL BE THE PREDOMINANT PRECIP TYPE
THROUGH 06-08Z. HAVE MAINTAINED A PERIOD OF MODERATE FREEZING RAIN
FOR ABOUT 4 HOURS TO ACCOUNT WHEN HEAVIEST PRECIPITATION IS
EXPECTED TO FALL. AT KLAF...WARMER BOUNDARY LAYER AIR HAS HELPED
SWITCH PRECIP TO FREEZING RAIN AND EXPECT IT TO REMAIN SO THROUGH
THE EVENING BEFORE SLEET BEGINS TO MIX BACK IN AFTER MIDNIGHT.
KBMG MAY END UP BEING THE MOST CHALLENGING OF THE SITES. KBMG IS
REPORTING UP AT THE MOMENT AND 32F...BUT ALL SHORT RANGE MODEL
GUIDANCE BRINGS SLIGHTLY WARMER AIR TEMPERATURES BACK INTO THE
AREA DURING THE EVENING AND EARLY OVERNIGHT. WILL MAINTAIN -FZRA
AS THE PREDOMINANT PRECIP TYPE...BUT HAVE INTRODUCED A TEMPO GROUP
FROM 02-06Z FOR RAIN TO ACCOUNT FOR THE EXPECTED WARMER TEMPS. IFR
AND LOWER CONDITIONS WILL DEVELOP OVERNIGHT AS WELL.
AS COLDER AIR BEGINS TO SPREAD BACK SOUTH LATE TONIGHT AND EARLY
MONDAY...WILL BEGIN TO SEE PL MIX IN AFTER 07-08Z...THEN
EVENTUALLY A CHANGEOVER TO -SN FROM NORTH TO SOUTH BEGINNING
AROUND 09Z AT KLAF...AND SHORTLY AFTER DAYBREAK AT KHUF AND KIND.
SNOW SHOWERS WILL END BY EARLY AFTERNOON AS THE DEEPER MOISTURE
SHIFTS EAST. CEILINGS WILL SLOWLY LIFT BACK UP TO AROUND 1500FT
WITH SOME CLEARING LATE AS DRIER AIR BUILDS IN. IT WILL BECOME
GUSTY AS WELL...WITH NORTHERLY WINDS GUSTING TO 20-25KTS.
EXPECT UPDATES THROUGH THE EVENING AS THIS FLUID WINTER STORM
EVOLVES. CANNOT STRESS ENOUGH THAT ONE DEGREE AND A MATTER OF
MILES CAN MAKE ALL THE DIFFERENCE IN PRECIP TYPE. AS STATED
ABOVE...ICING IS POSSIBLE AT ALL TERMINALS BUT GREATEST CONCERNS
REMAIN AT KHUF AND KIND WHERE POTENTIAL FOR UP TO A QUARTER INCH OF
ICE ACCUM EXISTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 AM TO 1 PM EST MONDAY FOR INZ037-
039>042-045>049-051>057.
ICE STORM WARNING UNTIL 7 AM EST MONDAY FOR INZ037-039>042-
045>049-051>057.
WINTER WEATHER ADVISORY UNTIL 1 PM EST MONDAY FOR INZ021-028>031-
035-036-038-043-044-060>065-067>072.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM...NIELD
AVIATION...RYAN
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
905 PM EST SUN JAN 11 2015
.SYNOPSIS...
ISSUED AT 438 PM EST SUN JAN 11 2015
A STORM SYSTEM MOVING UP THE OHIO VALLEY TONIGHT WILL COMBINE
WITH A COLD FRONT DROPPING SOUTHEAST ACROSS THE GREAT LAKES WILL
CAUSE SNOW TO OVERSPREAD OUR AREA FROM SOUTH TO NORTH THIS
EVENING. THE SNOW WILL CONTINUE ACROSS THE AREA OVERNIGHT BEFORE
TAPERING OFF FROM NORTHWEST TO SOUTHEAST MONDAY MORNING. SNOW
WILL BE MIXED WITH SLEET AND FREEZING RAIN SOUTH OF ROUTE 24.
TOTAL SNOW ACCUMULATIONS ARE EXPECTED TO BE 2 TO 4 INCHES. LOW
TEMPERATURES WILL BE IN THE UPPER 20S TONIGHT. TEMPERATURES WILL
FALL THROUGH THE AFTERNOON ON MONDAY...REACHING THE SINGLE DIGITS
ABOVE TO SIGNLE DIGITS BELOW ZERO BY TUESDAY MORNING.
&&
.UPDATE...
ISSUED AT 850 PM EST SUN JAN 11 2015
FORECAST LOOKS IN GOOD SHAPE AT THE MOMENT PER LATEST
OBSERVATIONS AND REPORTS. HIRES GUIDANCE SURFACE TEMPS LOOK TO BE A
COUPLE DEGREES TOO COLD ACROSS THE SOUTHEAST WITH RUC13 AND HRRR
SHOWING TEMPERATURES AT 02Z OF 28 TO 29 DEGREES WHERE SFC
OBSERVATIONS ARE 31 TO 33. 01Z RUC WHICH JUST CAME IN IS NOW A
DEGREE WARMER. A CALL TO PORTLAND AWOS AROUND 0130Z INDICATED SNOW
AND 33F WITH THE HIGHER RETURNS THAT MOVED THROUGH THAT AREA. SO
FAR SPOTTER REPORTS INDICATE A TENTH OF AN INCH OR LESS OF ICE IN
THE SOUTH WITH A MIX OF SLEET AND SNOW AT TIMES WITH HEAVIER
RETURNS. LATEST HI RES WARM T LAYER TEMPS HAVE LOWERED TO 0C OR
COLDER BUT GUIDANCE IS WARMING THESE TO BETWEEN 2 AND 2.5C IN THE
FAR SOUTHEAST BY 04-06Z WITH NEXT WAVE OF PCPN IN CENTRAL INDIANA
COMING NORTHEAST. THIS COULD BRING ADDITIONAL FZRA BACK TO THIS
AREA. INTERESTING TO NOTE THAT ONLY MODEL TO REALLY CAPTURE 02Z
SFC TEMPS IN THE SOUTHEAST WAS LOCAL 12KM WRF. THIS MODEL BRINGS
SFC TEMPS UP TO AROUND 33 TO 34 WITH NEXT SURGE OF HEAVIER PCPN.
THIS MAY BE OVERDONE WITH RATHER UNIFORM TEMPS AROUND 31 TO 32
ACROSS CENTRAL INDIANA. REGARDLESS...CURRENT ADVISORY LOOKS ON
TRACK WITH MIX OF PCPN CONTINUING IN THE SOUTH AND SOUTHEAST.
TRANSITION TO SNOW CENTRAL AND NORTH. REPORTS ANYWHERE FROM AN
INCH CENTRAL TO NEAR 3 INCHES IN BERRIEN COUNTY ALONG LAKESHORE.
RADAR MOSAIC SHOWING DRY SLOT TRYING TO FILL IN. HIRES GUIDANCE
WANTS TO SINK FGEN FORCED AREA OF LIGHT SNOW CURRENTLY TO OUR
NORTHWEST SOUTH ACROSS THE AREA OVERNIGHT. THIS SEEMS REASONABLE
AND SHOULD THEN END MONDAY MORNING FROM NORTHWEST TO SOUTHEAST. NO
SIGNIFICANT CHANGES PLANNED TO SNOW AMOUNTS. PREVIOUS UPDATE
INCREASED ICING AMOUNTS TO BETWEEN ONE AND TWO TENTHS AND THIS
ALSO STILL ON TARGET FOR NOW. WILL CONTINUE TO MONITOR HIRES
GUIDANCE TRENDS WITH NEXT BATCH OF HEAVIER PCPN.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 314 PM EST SUN JAN 11 2015
MAIN FOCUS REMAINS SNOW AMOUNTS AND PTYPE INTO TONIGHT/MON AM...
GOOD MOISTURE CONVERGENCE IN 900-700 MB LAYER EXPECTED TO
OVERSPREAD THE AREA LATE AFTN/EVE AS A SHORTWAVE OVER MISSOURI
SHEARS NORTHEAST INTO LOWER LAKES CONFLUENT ZONE. THE RESULTING
FGEN RESPONSE AND SURGE OF MOISTURE IN WARM CONVEYOR BELT (PWATS
> 0.70 INCHES AND 1000-850 MB MIXING RATIOS APPROACHING 4 G/KG
SERN HALF) UNDER THE RIGHT ENTRANCE REGION OF A 150 KT UPPER JET
WILL SUPPORT A MODERATE PCPN EVENT INTO THE EARLY OVERNIGHT.
DEEPER MOISTURE AND HEAVIER PCPN WILL EXIT THE AREA
OVERNIGHT/MONDAY MORNING BUT STILL EXPECT A BAND OF LIGHT SNOW TO
SINK SE THROUGH THE AREA MONDAY MORNING AS A MORE PRONOUNCED
NORTHERN STREAM SHORTWAVE REINVIGORATES FGEN ALONG LINGERING
BAROCLINIC ZONE.
PTYPE EXPECTED TO BE MAINLY SNOW (MAYBE A BRIEF MIX AT ONSET) NW
OF HWY 24 WITH SLEET AND FREEZING RAIN LIKELY MIXING IN TO THE
SOUTHEAST THIS EVENING AS WEAK WARM LAYER ALOFT LIFTS IN. THIS
WARM THERMAL PROFILE WILL LIKELY LIMIT SNOW RATIOS TO NEAR/JUST
BELOW CLIMO...ESPECIALLY SERN ZONES WHERE WINTRY MIX IS EXPECTED.
SNOW TOTALS GRIDDED UP BASED ON RELATIVELY CONSISTENT QPF AND
10-12:1 RATIOS ONCE AGAIN CAME TO BETWEEN 2-4" MOST LOCATIONS.
THERE REMAINS CONCERN FOR MESOBANDING AND LOCALLY HEAVIER AMOUNTS
GIVEN STEEPER LAPSE RATES/REDUCED STATIC STABILITY MODELED JUST
ABOVE THE FRONTAL SLOPE...ALTHOUGH BANDS EXPECTED TO BE TRANSIENT
FOR THE MOST PART KEEPING TOTALS IN CHECK. HEAVIER PRECIP RATES
AND POTENTIAL FOR SOME LIGHT ICING SE OF HWY 24 WARRANTED A
WINTER WX ADVISORY.
&&
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 314 PM EST SUN JAN 11 2015
RATHER BENIGN PATTERN TO PREVAIL FOR MUCH OF THE LONG TERM
PERIOD. FORECAST PERIOD TO BEGIN WITH HIGH PRESSURE BUILDING INTO
THE REGION BRINGING SHALLOW ARCTIC INTRUSION WITH IT. HIGH
PRESSURE CENTER WILL MOVE OVER THE AREA BY TUESDAY
NIGHT...YIELDING CLEAR SKIES LIGHT WINDS...AND WITH SNOW COVER
IDEAL RADIATIONAL COOLING WILL SEND LOWS BELOW ZERO FOR WEDNESDAY
MORNING. REST OF THE WEEK WILL FEATURE GRADUAL WARMING TREND AS
OVERALL PATTERN TRENDS MORE TOWARD A ZONAL FLOW. SPLIT FLOW WILL
HAVE SYSTEM MOVING ACROSS THE US/CANADIAN BORDER WHILE SOUTHERN
STREAM WAVE MOVES THROUGH THE GULF COAST STATES ON
THURSDAY...LEAVING OUR AREA IN BETWEEN AND DRY. MEDIUM RANGE
MODELS INDICATING STRONG JET DYNAMICS STREAMING IN FROM THE
PACIFIC INTO THE WEST COAST THAT WILL INDUCE SOME DOWNSTREAM
RIDGING AND ALSO LEAD TO A FLATTENING OF THE PATTERN AND A BROAD
ZONAL FLOW ACROSS THE CONUS. WARMING TREND WILL ENSUE GOING INTO
THE WEEKEND WITH TEMPS AOA NORMAL BY SATURDAY. MOS GUIDANCE
TRENDING POPS TOWARD CLIMO BY THE END OF THE PERIOD AS ONE WOULD
EXPECT...BUT NOT SEEING INDICATION THAT MODELS ARE CONVERGING
TOWARD A SOLUTION THAT WOULD WARRANT INTRODUCING POPS ATTM SO
WILL MAINTAIN DRY FCST THRU THE PERIOD FOR NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 533 PM EST SUN JAN 11 2015
LITTLE CHANGE TO FORECAST AT THIS POINT FOR TAF SITES. MAY NEED TO
PROLONG PL AT KFWA A FEW MORE HOURS BASED ON LATEST GUIDANCE
SHOWING WARM LAYER ALOFT PUSHING A BIT FARTHER NORTH. WILL ALSO BE
WATCHING OBSERVATIONS CLOSELY FOR INDICATIONS OF ANY FREEZING RAIN
MOVING IN. THIS OCCURRING SOUTH OF FORT WAYNE BUT INCHING FURTHER
NORTH. CHANGEOVER TO SNOW LATER THIS EVENING. KSBN TO REMAIN WELL
IN COLD AIR AND EXPECTING MAINLY SNOW THERE WITH A FEW INCHES OF
ACCUMULATION STILL ON TRACK.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST MONDAY FOR INZ026-027-
032>034.
WINTER WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR INZ020-
022>025.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL NOON EST MONDAY FOR OHZ016-024-025.
LM...SMALL CRAFT ADVISORY FROM 9 AM MONDAY TO 4 AM EST TUESDAY FOR
LMZ043-046.
&&
$$
UPDATE...LASHLEY
SYNOPSIS...MURPHY
SHORT TERM...STEINWEDEL
LONG TERM...JAL
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 QUAD CITIES IA IL
348 PM CST SAT JAN 10 2015
.SYNOPSIS...
ISSUED AT 344 PM CST SAT JAN 10 2015
NOT AS COLD TODAY WITH WARM ADVECTION ON GUSTY SOUTHERLY WINDS AHEAD
OF NEXT COLD FRONT ALLOWING TEMPS TO CLIMB INTO THE UPPER TEENS
NORTH... TO THE UPPER 20S TO AROUND 30 DEGS SOUTH. AFOREMENTIONED
COLD FRONT EXTENDS FROM CENTRAL MN THROUGH CENTRAL NE AT MID AFTN.
UPPER AIR ANALYSIS AND WATER VAPOR SHOWS SPLIT FLOW ACROSS CONUS
WITH DRY AND COLD WEST/NORTHWEST FLOW PREVAILING OVER THE MIDWEST.
100-120+ KT CYCLONICALLY CURVED JET EXTENDS FROM ALBERTA AND
SASKATCHEWAN PROVINCES TO THE GREAT LAKES SHUTTLING COUPLE OF
IMPULSES. MAIN SYSTEM OF INTEREST IS SHORTWAVE TROUGH IN SOUTHERN
STREAM SEEN EJECTING E/NE INTO SOUTHEAST NM AND WEST TX THIS AFTN.
THIS WEAKENING SYSTEM WILL LOOK TO INTERACT WITH FRONT TO BRING LIGHT
SNOW TO PORTIONS OF THE AREA SUNDAY AFTN-EVE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 344 PM CST SAT JAN 10 2015
FRONT TO SAG SOUTHEAST TONIGHT AND WILL BE APPROACHING THE FAR NW
CWA TOWARD 12Z. THIS MEANS NEARLY ALL OF THE CWA WILL RESIDE IN
THE PRE-FRONTAL WARM SECTOR TONIGHT CHARACTERIZED BY SOUTHERLY
WINDS... GUSTY AT TIMES THIS EVENING... AND MUCH WARMER LOWS IN THE
GENERAL RANGE FROM AROUND 10F TO 19F. SKIES LOOK TO GENERALLY BE
PARTLY TO MOSTLY CLOUDY.
SUNDAY...COLD FRONT TO CONTINUE SAGGING SOUTHEAST AND SHOULD BE
ROUGHLY BISECTING CWA FROM SOUTHWEST TO NORTHEAST BY 00Z. WEAKENING
SOUTHERN STREAM SHORTWAVE TROUGH AND ATTENDANT MOISTURE AND PCPN
SHIELD IS SUGGESTED TO PASS MAINLY SOUTHEAST OF CWA SUNDAY AFTN.
HOWEVER... GLANCING BOUT OF FORCING ON NORTH SIDE OF SYSTEM LOOKS TO
INTERACT WITH FRONT FOR DEVELOPMENT OF LIGHT SNOW BY MID TO LATE
AFTERNOON FOCUSING MAINLY IN CORRIDOR BETWEEN IOWA CITY AND GALESBURG
ESPECIALLY NEAR SQI-MLI-MPZ AXIS IN RIBBON OF ENHANCED FRONTOGENETICAL
FORCING AIDED BY RIGHT ENTRANCE REGION OF GREAT LAKES JET. FORCING
LOOKS PRIMARILY JUST OUTSIDE OF DENDRITIC GROWTH ZONE AND THUS
MAINLY LIGHT ACCUMS LESS THAN AN INCH WHICH WILL BE CHEWED SOME BY
TEMPS NEARING THE FREEZING MARK IN SOME AREAS. TEMPS SHOULD BE
WARMEST IN SOUTH/SOUTHEAST CWA AND AROUND THE FREEZING MARK BEING
PRE- FRONTAL WHILE ELSEWHERE GENERALLY 20S FOR HIGHS. DPROG/DT
DOES SHOW SOME SLOWING OF FRONT WHICH COULD RESULT IN SLIGHTLY
WARMER HIGHS MOST AREAS AND ALSO COULD RESULT IN PUSHING PCPN CHCS
A BIT FURTHER NORTHWEST FOR THE AFTN.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 344 PM CST SAT JAN 10 2015
SUNDAY NIGHT...CONTINUING TO SIDE WITH THE 12Z/18Z NAM AND 12Z ECMWF
FOR THE SUNDAY NIGHT ELEVATED FORCING SNOW EVENT AS THE NORTHERN
STREAM UPPER TROF SHEARS TOWARD THE WESTERN GRT LKS...AND THE DEEP
SOUTHERN PLAINS TROF LIFTS EAST-NORTHEASTWARD TOWARD THE OH RVR
VALLEY. THE FORCING AND MOISTURE PLUME PROPAGATION PATHS TAKE THE
BULK OF THE DEEPER SATURATION AND PRECIP AREAS/SEEN NOW ACRS EASTERN
TX/ TO THE EAST AND SOUTHEAST OF THE DVN CWA SUNDAY NIGHT. BUT
300-305K ISENTROPIC LIFT SFC/S WHICH ARE DEPICTING THE PRECIP BAND
CURRENTLY ACRS THE SOUTHERN TX PANHANDLE...ACRS THE SOUTHEASTERN
THIRD OF THE DVN CWA WITH FURTHER DEVELOPMENT AS IT PROPAGATES
NORTHEASTWARD INTO THE AREA SUNDAY EVENING. THE INITIAL ELEVATED/H7
MB/ FRONTOGENETICAL FORCING WING IS DEPICTED BY THE NAM TO SET UP
ALONG A NARROW AXIS GENERALLY DURING THE 6-9 PM CST TIME WINDOW FROM
MT PLEASANT IN SE IA...TO THE EASTERN QUAD CITIES...TO NEAR STERLING
IL WITH AN INCH OF SNOW ACCUM POSSIBLE BEFORE IT SHIFTS EAST. THE 12Z
ECMWF GENERALLY TARGETS THE SOUTHEASTERN HALF OF THE CWA WITH A FEW
TENTHS OF AN INCH OF SNOW...TO 1.5 INCHES FROM 00Z-12Z MON WITH THE
HIGHER AMOUNTS EAST OF THE MS RVR. ISENTROPIC LIFT AND SATURATION
PROGS SUGGEST SOME 2 INCH AMOUNTS POSSIBLE ALONG AND EAST OF A LINE
FROM CARTHAGE IN WEST CENTRAL IL...TO MONMOUTH IL AND TO PRINCETON IL
BY THE TIME THE SNOW DECLINES AND SHIFTS EAST LATE SUNDAY NIGHT/EARLY
MON MORNING. FOR NOW WILL ADJUST HIGH CHC AND LIKELY POPS A BIT
FURTHER TO THE WEST/NORTHWEST...WITH 1 TO 1.5 INCHES ADDITIONAL SNOW
ACCUMS/ON TOP OF SUNDAY AFTERNOON/ ALONG AND EAST OF A LINE FROM
MEMPHIS MO...TO ALEDO IL...TO NORTHWEST OF PRINCETON IL. BUT
ADDITIONAL SHIFTS WILL HAVE TO BE WARY OF AN ENHANCED BAND OF 1+
INCHES POSSIBLE SETTING UP ALONG THE NAM INDICATED BAND FURTHER TO
THE NORTHWEST AS DESCRIBED ABOVE. NORTH WINDS PICKING UP BEHIND THE
SYSTEM/S ASSOCIATED SFC COLD FRONT AFTER MIDNIGHT TO 10-20 MPH/THE
HIGHER VALUES ACRS THE NORTHWESTERN CWA/...WITH TEMP DROP OFF LATE
TO THE FCST LOWS...LARGE THERMAL GRADIENT FROM NW-TO-SE.
MONDAY AND TUESDAY...ROUND OF RE-ENFORCING COLD THIS PERIOD AS A
STRONG 1045+ MB CANADIAN HIGH BUILDS DOWN THE UPPER MIDWEST MON AND
SETTLES OVERHEAD BY TUE. INCOMING RIDGE GRADIENT TO PRODUCE
NORTHERLY SFC WINDS OF 15-20+ MPH ON MON...WILL MIX UP LATE MORNING
MIDDAY HIGHS IN THE TEENS BEFORE COLD ADVECTING AS THE AFTERNOON
PROGRESSES FOR A TEMP DROP-OFF. SFC WINDS TO DECREASE AS MON NIGHT
PROGRESSES INTO EARLY TUE MORNING...THIS TO ALLOW FOR THE PROJECTED
COLD SUB-ZERO LOWS ACRS MUCH OF THE DVN CWA BY TUE MORNING. BUT
EVEN DECREASING WINDS OF 10 MPH OR LESS WILL COMBINE WITH THE FRESHLY
ARRIVED CANADIAN AIR TO PRODUCE WIND CHILLS OF 10 TO 20 BELOW ACRS
AT LEAST THE NORTHWESTERN HALF OF THE DVN CWA LATE MON NIGHT INTO MID
TUE MORNING. SUNSHINE AND LLVL COLD POOL SEEPING OFF TO THE EAST
AMY ALLOW FOR AFTERNOON TEMP RECOVERY BACK INTO THE TEENS TUE.
COLDEST LOWS TUE NIGHT WITH A QUICK TEMP DROP OFF AFTER SUNSET EAST
OF THE MS RVR CLOSER TO PASSING SFC RIDGE CENTER.
WEDNESDAY THROUGH NEXT SATURDAY...LATEST 12Z RUN MEDIUM RANGE MODELS
AND ENSEMBLES SUGGEST THE DVN CWA TO GENERALLY LAY OUT UNDER SPLIT
FLOW REGIME THIS PERIOD IN BETWEEN MORE ACTIVE SOUTHERN STREAM AND
LOW AMPLITUDE DIGGING L/W TROF OUT OF CENTRAL CANADA INTO THE
EASTERN GRT LKS IN THE NORTHERN STREAM. THE AIRMASS WILL STILL LOOK
TO MODIFY...WITH THE LARGER THERMAL JUMP FRI INTO SAT AS CLIPPER IN
THE NORTHERN STREAM SHUTTLE ALONG TO THE NORTH OF THE REGION AND
DRAW WARMER AIR UP FROM THE SOUTHERN PLAINS. LONGER RANGE THERMAL
PROGS BY THE 12Z GFS AND ECMWF SUGGEST TEMPS MAY RECOVER BACK INTO
THE 30S BY FRI...WITH SOME LOWER 40S POSSIBLE SOUTH OF I80 BY SAT
EVEN TAKING INTO ACCOUNT LINGERING SNOW COVER. THE FCST LOOKS DRY
THROUGH THE FIRST HALF OF THE WEEKEND AS WELL...WITH LONG RANGE PROGS
SUGGESTING THE NEXT PRECIP CHANCE NOT COMING UNTIL NEXT SUNDAY NIGHT
OR MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1151 AM CST SAT JAN 10 2015
VFR CONDITIONS EXPECTED THROUGH THE TAF CYCLE WITH MAINLY MID TO
HIGH LEVEL CLOUDINESS AND CIGS AT OR ABOVE 4-6KFT AGL. GUSTY
SOUTHERLY WINDS OF 10-20 KTS EXPECTED REST OF TODAY. THIS EVENING
MAY SEE WINDS DECOUPLE ENOUGH TO RESULT IN WIND SHEAR WITH MODEL
SOUNDINGS SHOWING AROUND 40-45 KTS FROM SOUTHWEST IN THE
1500-2000 FT AGL LAYER WHILE SFC WINDS SOUTHERLY AROUND 10 KTS.
AS RESULT...HAVE GONE AHEAD AND ADDED MENTION OF LLWS AT ALL
SITES THIS EVENING INTO THE OVERNIGHT BEFORE LOW LEVEL JET SHIFTS
EAST. A COLD FRONT WILL SAG INTO THE AREA ON SUNDAY WITH WINDS
BECOMING LIGHT AND VARIABLE NORTHEAST IA AND MAINLY LIGHT SOUTHERLY
ELSEWHERE. RAP MODEL TRYS TO DEVELOP LOWER MVFR AND EVEN SOME IFR
CIGS AHEAD OF FRONT LATE TONIGHT AND SUNDAY MORNING... BUT NOT
CONFIDENT ENOUGH TO MENTION ATTIM DUE TO MODEL BL MOISTURE CONCERNS
BUT WILL CONTINUE TO MONITOR UPSTREAM TRENDS AND PASS ALONG TO NEXT
SHIFT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...05
SHORT TERM...05
LONG TERM...12
AVIATION...05
AREA FORECAST DISCUSSION
NWS DES MOINES IA
344 PM CST SAT JAN 10 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 344 PM CST SAT JAN 10 2015
TEMPERATURES AND CLOUD COVER WERE THE MAIN FORECAST ISSUE FOR
TONIGHT AS SURFACE HIGH PRESSURE MOVES EAST THIS EVENING ALLOWING
FOR A WEAK TROUGH TO PUSH INTO THE STATE OVERNIGHT. FORECAST
SOUNDINGS SUGGEST AN INVERSION DEVELOPING THIS EVENING TRAPPING
LOW LEVEL MOISTURE AND RESULTING IN A STRATUS SHIELD OVER CENTRAL
TO NORTHERN IOWA. PRETTY HIGH RH AT 925MB THIS EVENING AND ALSO
SHOULD BE A LITTLE ADDED MOISTURE WITH THE STRONG WAA TODAY OVER
THE SNOW PACK. INCREASE CLOUD COVER TONIGHT WHICH SHOULD HELP KEEP
OVERNIGHT LOWS UP SLIGHTLY WARMER THAN PREVIOUSLY FORECAST. THE
HOPWRF AND HRRR HAVE CLOUD COVER THROUGH MUCH OF THE NIGHT OVER
THE NORTHERN SECTION OF THE FORECAST AREA.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
ISSUED AT 344 PM CST SAT JAN 10 2015
A FEW MINOR ISSUES IN THE NEAR TERM...WITH MAINLY A DRY AND QUIET
FORECAST THROUGHOUT THE MID/LONG RANGE. SOUTHERN STREAM UPPER
LEVEL TROUGH WILL BE LIFTING OUT OF THE SOUTHERN HIGH PLAINS
INTO THE OHIO VALLEY SUNDAY INTO EARLY MONDAY. ADDITIONALLY A
NORTHERN STREAM TROUGH WILL BE DROPPING THROUGH THE NORTHERN
PLAINS AND INTO THE GREAT LAKES WITH THAT WAVE SOMEWHAT SHEARING
APART AS IT DROPS SOUTH. WAA AND SOME WEAK THETA-E ADVECTION WILL
CREEP INTO THE FAR SOUTHEASTERN CWA WITH THE SOUTHERN STREAM
TROUGH...WHICH WILL BRING A CHANCE FOR SOME LIGHT SNOW TO THE FAR
SOUTHEASTERN CWA SUNDAY NIGHT. NAM SHOWS DEEPER SATURATION KEEPING
THE PRECIP MAINLY VERY LIGHT SNOW...WHILE THE GFS DOES SHOW SOME
QUESTION AS TO THE DEEPER SATURATION AND ICE INTRODUCTION WITH A
POTENTIAL FOR SOME VERY LIGHT FZDZ. OVERALL THE BULK OF THE PRECIP
IS EXPECTED TO STAY TO THE SOUTH AND SOUTHEAST OF THE CWA...SO
ONLY LIGHT ACCUMULATIONS UNDER AN INCH ARE POSSIBLE AND WENT WITH
HIGH CHANCE POPS. A STRONGER COLD FRONT WILL PUSH THROUGH THE CWA
WITH THE NORTHERN STREAM TROUGH AND COULD BRING SOME FLURRIES
SUNDAY NIGHT TO THE REMAINDER OF THE CWA...AND SOME GUSTY WINDS
INTO MONDAY. COLD ARCTIC HIGH PRESSURE TO BUILD INTO THE CWA FOR
MONDAY NIGHT INTO TUESDAY WITH TEMPS FALLING WELL BELOW NORMAL
AGAIN.
NORTHWESTERLY UPPER LEVEL FLOW REMAINS IN PLACE INTO
THURSDAY...WITH THE FLOW FLATTENING OUT SOME TOWARD THE WEEKEND.
THE MAIN PUSH OF SHORTWAVES SHOULD REMAIN TO THE NORTH OF THE
CWA...SO EXPECT DRY CONDITIONS WITH MAINLY AN INCREASE IN CLOUD
COVER. TEMPERATURES WARM ALOFT AS WELL THROUGH THE END OF THE
PERIOD...SO A WARMING TREND IS ON TAP THROUGH THE WEEKEND.
TEMPERATURES ARE EXPECTED TO REBOUND CLOSER TO THE SEASONAL
AVERAGE OR EVEN PUSH ABOVE AVERAGE TOWARD THE END OF THE FORECAST
PERIOD.
&&
.AVIATION...10/18Z
ISSUED AT 1133 AM CST SAT JAN 10 2015
HAVE INTRODUCED MVFR CIGS ACROSS NORTHERN IOWA BY TONIGHT AS AN
INVERSION DEVELOPS THIS EVENING AND LOOKS TO LOCK IN MOISTURE
UNDERNEATH FROM THE WAA TODAY. LOWER CONFIDENCE WITH THE STRATUS
DECK DIMINISHING SUNDAY MORNING AND LOOKS LIKE THE INVERSION
WEAKENS BY AROUND 14Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...BEERENDS
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1207 PM CST SAT JAN 10 2015
.UPDATE...
ISSUED AT 1112 AM CST SAT JAN 10 2015
UPDATED MAINLY TO INCREASE CLOUD COVER TO PTSUNNY TO CLOUDY WITH
VEERING LOW LEVEL JET AND ATTENDANT WAA AND CONVERGENCE LEADING
TO EXPANSION OF 5-6KFT AGL CIGS... WHILE CIRRUS ALSO INCREASING
ATTENDANT TO APPROACHING RIGHT ENTRANCE REGION OF UPPER MIDWEST
JET STREAK. TWEAKED TEMPS SOME BUT RANGE OF MID TEENS TO MID 20S
STILL LOOKS ON TRACK DESPITE INCREASE IN CLOUDS AS THIS IS DUE TO
WAA ON GUSTY SOUTHERLY WINDS.
&&
.SYNOPSIS...
ISSUED AT 305 AM CST SAT JAN 10 2015
HIGH PRESSURE RIDGE EXTENDED FROM KY TO NORTH TX WITH CLEAR SKIES
AND A SOUTHWEST WIND OF 5 TO 10 MPH ACROSS THE DVN CWA. THESE WINDS
HAVE KEPT TEMPERATURES HIGHER THAN FORECAST AND IN FACT WIND CHILL
ADVISORY CRITERIA WAS FINALLY MET AT 2 AM...AND ONLY ALONG AND NORTH
OF HIGHWAY 30. 2 AM READINGS RANGED FROM 9 BELOW AT CEDAR RAPIDS TO
5 ABOVE AT FORT MADISON. AT SOME LOCATIONS TEMPERATURES HAVE ACTUALLY
RISEN IN THE PAST COUPLE OF HOURS.
ELSEWHERE...STRONG LOW LEVEL WARM AIR ADVECTION WAS KICKING IN
ACROSS THE CENTRAL PLAINS AND AN AREA OF LOWER CLOUDS WAS NOTED IN
CENTRAL KS. TEMPERATURES WERE IN THE 20S IN WESTERN KS AND INTO
WEST TX.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CST SAT JAN 10 2015
HEADLINES...HAVE CANCELLED THE WIND CHILL ADVISORY FOR SE IA AND
WESTERN IL BUT KEPT THE REMAINDER OF THE ADVISORY GOING UNTIL 9 AM.
FORECAST FOCUS ON WARMER TEMPERATURES.
TODAY...AFTER A CHILLY START TO THE DAY STRONG 925-850 MB WARM AIR
ADVECTION DEVELOPS. THERE WILL BE PLENTY OF SUNSHINE THIS MORNING
WITH INCREASING MID/HIGH CLOUDS IN THE AFTERNOON. HOWEVER...SOUNDINGS
ARE NOT COMPLETELY SATURATED SO THERE STILL SHOULD BE SOME SUNSHINE.
AFTERNOON TEMPERATURES SHOULD PUSH INTO THE LOWER TO MID 20S...EXCEPT
TEENS IN NW IL. 850 MB WINDS INCREASE TO 40-45 KNOTS BY AFTERNOON
BUT DON`T SEE DEEP MIXING TO BRING DOWN THESE STRONG OF WINDS TO
THE SURFACE. FOR NOW BELIEVE SOUTHWEST WINDS SHOULD GUST TO AROUND
25 MPH ESPECIALLY IN THE AFTERNOON...POSSIBLY TO 30 MPH AT SOME LOCATIONS.
TONIGHT...PARTLY/MOSTLY CLOUDY SKIES ACROSS THE CWA AND WITH SOUTH
WINDS MINIMUM TEMPERATURES WILL FALL INTO THE TEENS AT MOST LOCATIONS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 305 AM CST SAT JAN 10 2015
A WEAK SHORTWAVE IS LOOKING MORE LIKELY TO BRING LIGHT...BUT
MEASURABLE SNOW TO THE PARTS OF THE AREA LATE SUNDAY INTO SUNDAY
NIGHT. THIS IS FOLLOWED BY A FRESH ARCTIC AIRMASS THAT WILL KEEP
BELOW NORMAL TEMPERATURES THROUGH MIDWEEK. A TRANSITION TO A MORE
ZONAL UPPER LEVEL FLOW WILL BRING IN A MORE PACIFIC AIRMASS...
RESULTING IN WARMER TEMPERATURES LATE IN THE WEEK. BEYOND SUNDAY
NIGHT...THE UNFAVORABLE STORM TRACKS IN THE SPLIT FLOW PATTERN WILL
KEEP STORM SYSTEMS WELL NORTH AND SOUTH OF THE REGION...RESULTING IN
A DRY FORECAST.
SUNDAY INTO SUNDAY NIGHT...WARM AIR ADVECTION ON LIGHT SOUTH
SOUTHWEST WINDS AHEAD OF THE APPROACHING FRONT WILL LIKELY BOOST
TEMPERATURES INTO THE 20S CENTRAL AND NORTH...AND POSSIBLY INTO THE
LOWER 30S SOUTH...DESPITE THICKENING HIGH CLOUD COVER. THE LATEST
MODELS...LED BY THE GFS AND ECMWF...CONTINUE TO TREND FURTHER NORTH
WITH PRECIPITATION BREAKING OUT ALONG AND AHEAD OF THIS FRONT AS
UPPER LEVEL FORCING WITH AN APPROACHING SHORTWAVE OVERSPREADS THE
AREA IN THE AFTERNOON. HAVE INCREASED AFTERNOON POPS FOR WHAT
SOUNDINGS INDICATE SHOULD BE ALL LIGHT SNOW WITH UP TO A DUSTING
POSSIBLE IN THE SOUTHEAST IN THE LATE AFTERNOON. THE BEST FORCING
ARRIVES IN THE EVENING...AND WITH INCREASING CONFIDENCE FROM GOOD
RUN TO RUN CONSISTENCY IN THE MODELS...HAVE INCREASED POPS TO LIKELY
ACROSS THE SOUTHEAST...AND HAVE SPREAD CHANCE WORDING INTO E CENTRAL
IA AND NW IL. WHILE MOISTURE WILL BE LIMITED...THE QUICK SHOT OF LIFT
INTO A FAVORABLY COLD LAYER ALOFT LOOKS SUFFICIENT TO MENTION
ACCUMULATIONS UP TO AROUND 1 INCH OVER FAR SOUTHEAST MO...FAR
SOUTHEAST IA AND W CENTRAL IL...WITH MUCH LIGHTER AMOUNTS TO THE
NORTH. COLD AIR ADVECTION SPILLS IN BEHIND THE ARCTIC FRONT THAT
PUSHES THROUGH AND EXITS THE SOUTHEAST AFTER MIDNIGHT...LEADING TO
LOWS FROM AROUND 5 NORTH TO UPPER TEENS IN THE SOUTHEAST BASED ON A
MODEL BLEND. HAVE INTRODUCED FLURRIES FOR THE REMAINDER OF THE
FORECAST AREA FOR OVERNIGHT AS A SECONDARY MID LEVEL WAVE MOVING
INTO THE GREAT LAKES MAY PROVIDE ADDITIONAL WEAK FORCING.
ARCTIC HIGH PRESSURE BUILDS INTO THE REGION TUESDAY INTO
WEDNESDAY...LEADING TO ANOTHER ROUND OF WELL BELOW NORMAL
TEMPERATURES. TUESDAY MORNING WILL BE THE COLDEST PERIOD AS HIGH
PRESSURE...ROUGHLY AROUND 1045 MB...IS SHOWN OVER THE IA/MN BORDER
REGION TOWARD 12Z. IF COMPLETE DECOUPLING OCCURS AND THERE ARE NO
MID OR LEVEL HIGH CLOUDS...PROGGED LOWS FROM AROUND ZERO SOUTH AND
EAST TO THE NEGATIVE SINGLE DIGITS NORTH AND WEST LOOK REASONABLE.
MODEL CONSENSUS INDICATES A POSSIBLE WEAK SHORTWAVE PUSHING THROUGH
AROUND WED NIGHT...BUT SUGGEST LITTLE MORE THAN A WIND SHIFT AT THE
SURFACE...TO KEEP A DRY FORECAST GOING THROUGH THE REST OF THE WEEK.
DAYTIME TEMPERATURES CONTINUE A WARMING TREND...RISING FROM THE
TEENS AND LOWER 20S TUE AND WED...INTO THE UPPER 20S TO LOWER 30S
THU AND FRI WITH MINS POSSIBLY RISING TO NEAR CLIMO...IN THE TEENS
OR WARMER...BY WEEK/S END.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1151 AM CST SAT JAN 10 2015
VFR CONDITIONS EXPECTED THROUGH THE TAF CYCLE WITH MAINLY MID TO
HIGH LEVEL CLOUDINESS AND CIGS AT OR ABOVE 4-6KFT AGL. GUSTY
SOUTHERLY WINDS OF 10-20 KTS EXPECTED REST OF TODAY. THIS EVENING
MAY SEE WINDS DECOUPLE ENOUGH TO RESULT IN WIND SHEAR WITH MODEL
SOUNDINGS SHOWING AROUND 40-45 KTS FROM SOUTHWEST IN THE
1500-2000 FT AGL LAYER WHILE SFC WINDS SOUTHERLY AROUND 10 KTS.
AS RESULT...HAVE GONE AHEAD AND ADDED MENTION OF LLWS AT ALL
SITES THIS EVENING INTO THE OVERNIGHT BEFORE LOW LEVEL JET SHIFTS
EAST. A COLD FRONT WILL SAG INTO THE AREA ON SUNDAY WITH WINDS
BECOMING LIGHT AND VARIABLE NORTHEAST IA AND MAINLY LIGHT SOUTHERLY
ELSEWHERE. RAP MODEL TRYS TO DEVELOP LOWER MVFR AND EVEN SOME IFR
CIGS AHEAD OF FRONT LATE TONIGHT AND SUNDAY MORNING... BUT NOT
CONFIDENT ENOUGH TO MENTION ATTIM DUE TO MODEL BL MOISTURE CONCERNS
BUT WILL CONTINUE TO MONITOR UPSTREAM TRENDS AND PASS ALONG TO NEXT
SHIFT.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...05
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...SHEETS
AVIATION...05
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
340 PM EST SAT JAN 10 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 340 PM EST SAT JAN 10 2015
19Z SFC ANALYSIS SHOWS MODIFIED ARCTIC HIGH PRESSURE OVER EASTERN
KENTUCKY. THIS HAS KEPT THE SKIES CLEAR AND WINDS LIGHT TODAY
THROUGHOUT THE AREA...HELPING TO SEND TEMPERATURES INTO THE UPPER
20S AND LOWER 30S FOR MOST OF THE CWA...DESPITE AN AWFULLY CHILLY
START. READINGS AT 3 PM RANGE FROM 25 DEGREES JUST NORTH OF FLEMING
COUNTY TO 34 DEGREES IN BELL AND HARLAN COUNTIES. DEWPOINTS...
MEANWHILE...ARE GENERALLY IN THE LOW SINGLE DIGITS ABOVE ZERO.
THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH THE RETREAT OF THE DEEP
TROUGH RESPONSIBLE FOR THIS LATEST COLD BLAST TONIGHT AND THE
APPROACHING OF A WEAKER SOUTHERN STREAM TROUGH INTO SUNDAY NIGHT.
HEIGHTS WILL SLOWLY RISE FROM TONIGHT INTO THE DAY SUNDAY THOUGH
MORE ENERGY WILL START TO STREAM IN FROM THE SOUTHERN STREAM LATER
SUNDAY THROUGH SUNDAY NIGHT. WITH THE GOOD MODEL AGREEMENT HAVE
FOLLOWED THE HRRR AND NAM12 MOST CLOSELY FOR THIS SHORT TERM PORTION
OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE ANOTHER CHILLY NIGHT...BUT MILDER THAN
LAST NIGHT...UNDER MOSTLY CLEAR SKIES AND LIGHT WINDS. THIS WILL SET
THE STAGE FOR A DECENT RIDGE TO VALLEY TEMPERATURE DIFFERENCE THROUGH
THE NIGHT. TEMPS WILL REBOUND THROUGH THE DAY SUNDAY EVEN AS CLOUDS
QUICKLY INCREASE AND THICKEN FROM THE WEST. WHILE READINGS ARE
EXPECTED TO RISE ABOVE FREEZING FOR THE ENTIRE CWA BEFORE THE CHANCES
OF LIGHT RAIN MOVE IN...THE DRY AIR IN PLACE MAY RESULT IN A MIXTURE
OF RAIN AND SLEET INITIALLY ALONG AND NORTH OF INTERSTATE 64. IN
ADDITION...THOUGH AIR TEMPERATURE WILL BE A COUPLE OF DEGREES ABOVE
FREEZING...PATCHY FREEZING RAIN WILL BE POSSIBLE DUE TO SUB FREEZING
ROAD TEMPERATURES AND SHADED LOCATIONS. ACCORDINGLY...HAVE ADDED A
TOUCH OF FREEZING RAIN TO THE WX GRIDS FROM LATE SUNDAY AFTERNOON
THROUGH EARLY EVENING. THEREAFTER...RAIN WILL BE THE PCPN TYPE
THROUGH THE REST OF THE NIGHT AS THE FIRST IN A SERIES OF LOW
PRESSURE WAVES RIDES THROUGH THE OHIO VALLEY. TEMPERATURES SHOULD BE
STEADY OR SLOWLY RISE THROUGH THE NIGHT. WILL ISSUE AN SPS TO ADDRESS
THE WINTRY MIX POTENTIAL FOR NORTHERN PARTS OF THE AREA LATE SUNDAY.
ONCE AGAIN USED THE BCCONSSHORT/SUPERBLEND AS A STARTING POINT FOR
THE T...TD...AND WIND GRIDS WITH SOME MODERATE TERRAIN BASED POINT
ADJUSTMENTS FOR LOWS TONIGHT. AS FOR POPS...ENDED UP IN LINE WITH THE
MET MOS THROUGH THE SHORT TERM.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 240 PM EST SAT JAN 10 2015
WHILE CONFIDENCE IS HIGH TO START THE UPCOMING WEEK...CONFIDENCE
FADES AS WE HEAD INTO TUESDAY AND BEYOND AS QUESTIONS SWIRL WITH
JUST HOW FAR SOUTH A FRONTAL BOUNDARY STALLS...WHICH IN TURN WILL
DETERMINE JUST HOW ACTIVE AND WHAT TYPE OF PRECIPITATION WE DEAL
WITH THROUGH THURSDAY.
TO START THE PERIOD...A SHORTWAVE TROUGH WILL BE PUSHING ACROSS THE
AREA MONDAY...YIELDING A DAMP DAY WITH PERIODS OF RAIN AND DRIZZLE.
LIFT AND MOISTURE ARE ALL PRESENT TO SUPPORT CATEGORICAL POPS
THROUGH MOST OF THE DAY. BY MONDAY NIGHT...DEEPER MOISTURE WILL EXIT
TO THE SOUTH AND EAST AS A COLD FRONT PUSHES SOUTH. HOWEVER...MODEL
SOUNDINGS REMAIN SUPPORTIVE OF PERSISTENT PERIOD OF DRIZZLE THROUGH
MONDAY NIGHT AND INTO TUESDAY. AT THE SAME TIME...SHALLOW COLD AIR
WILL BE SPREADING SOUTH BEHIND THE COLD FRONT. THIS WILL SET UP THE
STAGE FOR SOME LIGHT FREEZING RAIN/DRIZZLE INTO TUESDAY MORNING.
FORECAST CONFIDENCE ERODES ON TUESDAY...AS GFS KEEPS THE BOUNDARY
FARTHER NORTH...KEEPING THE THREAT OF PRECIPITATION AROUND FOR MUCH
OF SOUTHEAST KENTUCKY THROUGH THE DAY. ON THE OTHER HAND...THE ECMWF
SINKS THE FRONT SOUTHWARD AND KEEPS THE AREA DRY THROUGH TUESDAY AND
BEYOND. SIMPLY CANNOT DISCOUNT THE GFS SOLUTION...SO WILL KEEP SOME
LOW POPS AROUND THROUGH TUESDAY. AS TEMPERATURES ARE NOT EXPECTED TO
CLIMB PAST FREEZING...ANY PRECIPITATION THAT DOES EXIST COULD POSE
PROBLEMS THROUGH THE DAY. HOWEVER...GFS DOES SHOW SOME MID LEVEL
MOISTURE SPREADING BACK OVERHEAD...POSSIBLY SUPPORTING FEEDER/SEEDER
PROCESSES BY LATE MORNING INTO THE AFTERNOON HOURS. AT THE SAME
TIME...STILL A BIT OF A WARM NOSE ON THE GFS SOUNDINGS THROUGH THE
DAY...SO ANY SEEDER FEEDER PROCESSES COULD JUST INCREASE THE
INTENSITY OF ANY FREEZING RAIN. HOWEVER...ANY SLIGHT CHANGES IN THE
LOWER TEMPERATURE PROFILE ON TUESDAY WOULD SIGNIFICANT ALTER
PRECIPITATION TYPE. THUS...PLANNING TO GO FAIRLY LIBERAL ON THE
PRECIPITATION TYPES THIS FAR OUT AND GO WITH A MIXTURE OF
SLEET/FREEZING RAIN/AND POSSIBLY SOME SNOW ENTERING THE PICTURE ON
TUESDAY.
BY TUESDAY NIGHT INTO THURSDAY...THE QUESTIONS REMAIN ON HOW FAR
NORTH PRECIPITATION CHANCES WILL LAST. THE ECMWF REMAINS LESS
OPTIMISTIC ON ANY PRECIPITATION CHANCES...WHILE THE GFS KEEPS SOME
CHANCES IN SOUTHEAST KENTUCKY THROUGH THURSDAY. GIVEN THE MODELS
DISAGREEMENT HAVE OPTED FOR SOME LOW POPS THROUGH THURSDAY ACROSS
SOUTHEAST KENTUCKY. IF PRECIPITATION OCCURS...THE THREAT FOR
FREEZING DRIZZLE...SNOW...AND RAIN WILL CONTINUE. THUS...THERE IS A
CHANCE FOR A AN EXTENDED PERIOD OF FROZEN PRECIPITATION IN SOUTHEAST
KENTUCKY. ALL MODELS ARE TRENDING DRIER BY LATE THURSDAY INTO NEXT
WEEKEND...SO WILL DRY OUT THE FORECAST FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1250 PM EST SAT JAN 10 2015
HIGH PRESSURE...IN PLACE OVER THE AREA TODAY AND RETREATING TONIGHT
INTO SUNDAY...WILL PROVIDE VFR CONDITIONS ACROSS THE AREA THROUGH
THE BULK OF THE PERIOD. JUST TOWARD THE LAST 6 HOURS...SUNDAY
MORNING...WILL SOME HIGH THEN LOWER CLOUDS START TO MOVE IN FROM THE
WEST. BY 18Z CIGS NEAR MVFR WILL BE ON THE DOORSTEP OF WESTERN PARTS
OF THE FORECAST AREA. UNDER THE HIGH/S INFLUENCE...WINDS WILL BE AT 5
KTS OR LESS FROM THE SOUTH THIS AFTERNOON AND INTO THE NIGHT. THE
WINDS WILL START TO PICK UP FROM THE SOUTH SOUTHWEST DURING THE DAY
SUNDAY WITH SPEEDS OF 5 TO 10 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1244 AM EST SAT JAN 10 2015
.UPDATE...
ISSUED AT 1244 AM EST SAT JAN 10 2015
THE FORECAST REMAINS ON TRACK OVERNIGHT. WILL MERELY FRESHEN UP THE
HOURLY TEMPERATURES AND DEW POINTS...ACCOUNTING FOR THE LATEST TRENDS
IN OBSERVATIONS.
UPDATE ISSUED AT 1055 PM EST FRI JAN 9 2015
HOURLY GRIDS HAVE BEEN FRESHENED UP BASED ON RECENT OBSERVATIONS.
ALTHOUGH WINDS ARE STILL STIRRING A BIT IN SEVERAL AREAS...THE SHORT
TERM GUIDANCE STILL PROJECTS A SLACKENING PRESS GRADIENT OVERNIGHT AS
1038 MB SFC HIGH PRESSURE SETTLES ACROSS NORTHERN KY BY DAWN. THIS
SHOULD LEAD TO TEMPERATURES THAT HAVE NOT DROPPED TOO FAR INTO THE
TEENS AS OF YET TO DROP FAIRLY QUICKLY DURING THE OVERNIGHT
HOURS...AFTER THE MIDNIGHT TO 2 AM PERIOD.
UPDATE ISSUED AT 725 PM EST FRI JAN 9 2015
HIGH PRESSURE AT THE SFC AND ALOFT CONTINUES TO BUILD INTO THE REGION
BEHIND A COLD FRONT. THIS HIGH WILL USHER IN A VERY COLD AIR MASS WITH
PW OF LESS THAN ONE TENTH OF AN INCH. IN ADDITION...THE SFC PRESSURE
GRADIENT WILL DECREASE THROUGHOUT THE EVENING AND INTO THE OVERNIGHT
AND WITH DEW POINTS WELL DOWN INTO THE SINGLE DIGITS IF NOT BELOW
ZERO...A CHILLY NIGHT IS IN STORE. THE FORECAST MIN T IN THE SINGLE
DIGITS ABOVE ZERO APPEAR ON TARGET. THE HOURLY TEMPERATURE HAS BEEN
ADJUSTED BASED ON RECENT OBSERVATIONS. OVERALL..NO SIGNIFICANT
CHANGES WERE MADE ATTM.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 235 PM EST FRI JAN 9 2015
18Z SFC ANALYSIS SHOWS THE NEXT ARCTIC HIGH PRESSURE BUILDING INTO
EASTERN KENTUCKY FROM THE PLAINS. THE COLD FRONT ASSOCIATED WITH THIS
HAS MOVED WELL INTO EASTERN KENTUCKY...LEAVING ITS BAND OF
DISSIPATING CLOUDS AND SNOW BEHIND. JUST A FEW LINGERING FLURRIES
ARE FADING OUT OVER NORTHEASTERN PARTS OF THE FORECAST AREA. THE
SUNSHINE...AND POSITION JUST AHEAD OF THE ARCTIC BOUNDARY...HAS BEEN
ENOUGH FOR MANY LOCATIONS TO MAKE IT TO FREEZING OR A TICK ABOVE
THROUGH FAR SOUTHEAST KENTUCKY...BUT TEMPERATURES ARE NOW ON THE
WAY BACK DOWN. READINGS AT 2 PM RANGE FROM THE MID 20S IN THE
NORTHWEST TO THE LOWER 30S IN THE SOUTHEAST WHILE DEW POINTS ARE IN
THE LOW SINGLE DIGITS NORTH AND NEAR 10 DEGREES IN THE SOUTH. WINDS
THROUGH THE AREA HAVE SWITCHED TO MORE WESTERLY AT 10 TO 15 MPH WITH
A FEW GUSTS TO 25 MPH STILL POSSIBLE...WHILE A BIT MORE BEHIND THE
FRONT THE DIRECTION IS MORE FROM THE NORTHWEST.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM AS THEY
ALL DEPICT THE DEEP TROUGH RESIDENT THROUGH THE GREAT LAKES AND OHIO
VALLEY INTO SATURDAY MORNING. THIS TROUGH THEN SHIFTS OFF TO THE EAST
AND RELAXES ITS GRIP ON THE REGION AS HEIGHTS REBOUND QUICKLY BY
SATURDAY EVENING. ATTENTION WILL THEN TURN TO A DEVELOPING SOUTHERN
STREAM TROUGH MOVING INTO THE SOUTHERN PLAINS BY SUNDAY MORNING AS
THE FLOW TURNS SOUTHWESTERLY OVER KENTUCKY. WITH THE GENERAL MODEL
AGREEMENT HAVE FAVORED THE HIGHER RESOLUTION NAM12 AND HRRR FOR THE
SHORT TERM PORTION OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE BRISK CONDITIONS INTO THE EVENING AS
NORTHWEST WINDS BRING IN COLDER TEMPERATURES. THIS LATEST ARCTIC
SURGE WILL NOT BE QUITE AS COLD AS THE LAST ONE WITH TEMPERATURES
BOTTOMING OUT IN THE MID AND UPPER SINGLE DIGITS BY DAWN SATURDAY.
WITH THE WINDS SETTLING AS THE COLDEST AIR MOVES IN WE WILL BE SPARED
THE WORST OF THE WIND CHILLS...THOUGH...THEY WILL LIKELY DROP TO
NEAR ZERO IN A FEW PLACES TONIGHT. THE CHILLY HIGH PRESSURE WILL
MODERATE THROUGH THE DAY SATURDAY WITH AMPLE SUNSHINE RETURNING
TEMPERATURES INTO THE MIDDLE AND UPPER 20S BY AFTERNOON FOR MOST
PLACES ACROSS EASTERN KENTUCKY. SOME HIGH CLOUDS MAY BUILD INTO THE
REGION LATER SATURDAY NIGHT AS THE RETREATING HIGH SETS THE STAGE FOR
A SMALL TO MODERATE RIDGE/VALLEY TEMPERATURE SPLIT.
AGAIN USED THE BCCONSSHORT/SUPERBLEND AS A STARTING POINT FOR THE
T...TD...AND WIND GRIDS WITH SOME MINOR TERRAIN BASED POINT
ADJUSTMENTS FOR HIGHS AND LOWS. AS FOR POPS...ASIDE FROM SOME
LINGERING SINGLE DIGIT VALUES EARLY THIS EVENING IN THE FAR
EAST...HAVE BASICALLY ZEROED OUT POPS THROUGH SUNDAY MORNING...ALSO
IN LINE WITH MOS GUIDANCE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 230 PM EST FRI JAN 9 2015
SUNDAY SHOULD REMAIN DRY ACROSS THE AREA...BUT A WARM FRONT
ADVANCING NORTHWARD ACROSS THE AREA WILL BRING INCREASING CLOUDS.
DOWNSLOPING SOUTHEAST FLOW OFF THE HIGH TERRAIN WILL ATTEMPT TO KEEP
PRECIPITATION AT BAY THROUGH MOST OF THE DAY...BUT MODELS ARE
BEGINNING TO TREND SLIGHTLY FASTER WITH PRECIPITATION MAKING INTO
SOUTH CENTRAL KENTUCKY BY EARLY EVENING. FORTUNATELY...SURFACE
TEMPERATURES WILL BE MILDER WITH HIGHS INTO THE 40S ON SUNDAY WITH
WITH CLOUDS MOVING ON IN...THEY ARE NOT EXPECTED TO FALL OFF MUCH
INTO THE NIGHT. THUS...AS IT STANDS NOW...WE SHOULD SEE PRIMARILY
RAIN ACROSS THE AREA WITH THE SUBFREEZING TEMPERATURES (AND FREEZING
RAIN THREAT) STAYING JUST TO OUR NORTH. GIVEN THE ABUNDANCE OF DRY
AIR IN PLACE AT THE BEGINNING OF THE PRECIPITATION...WE MAY SEE A
BIT OF SLEET MIX IN INITIALLY BEFORE SEEING JUST RAIN. THE SLEET
THREAT WILL BE PRIMARILY BEFORE MIDNIGHT SUNDAY NIGHT. A SHORTWAVE
TROUGH WILL THEN PUSH ACROSS THE AREA ON MONDAY WITH A COLD FRONT
ADVANCING SOUTHWARD. THIS WILL KEEP PRECIPITATION ONGOING ON MONDAY
WITH THE POSSIBILITY OF RAIN MIXING WITH AND PERHAPS CHANGING TO
SNOW LATE MONDAY. HOWEVER...AS MENTIONED PREVIOUSLY...DEEPER
MOISTURE IS DEPARTING THROUGH THE EVENING HOURS MONDAY...AND WE MAY
LOSE THE ICE IN THE CLOUDS...WHICH WOULD SUPPORT MORE DRIZZLE VERSES
SNOW. REGARDLESS...ANY SNOW SHOULD HAVE VERY LOW IMPACT ON THE AREA
AS SURFACE TEMPERATURES REMAIN ABOVE FREEZING...LIMITING ANY SNOW
ACCUMULATION.
BY MONDAY NIGHT...MOISTURE DEPARTS THE AREA WITH ONLY A SLIGHT
CHANCE OF LINGERING RAIN OR SNOW ACROSS SOUTHEAST KENTUCKY INTO THE
OVERNIGHT HOURS. AFTER A DRY PERIOD ON TUESDAY...A STALLED FRONTAL
BOUNDARY JUST TO OUR SOUTH WILL LIFT BACK NORTH BY TUESDAY NIGHT
INTO WEDNESDAY WITH THE THREAT OF SNOW RETURNING TO THE AREA.
MOISTURE IS RATHER LIMITED...BUT A LIGHT DUSTING OF SNOW MAY BE
POSSIBLE. BETTER CHANCES OF SNOW WILL ARRIVE LATE WEDNESDAY NIGHT
INTO THURSDAY AS A BETTER SHORTWAVE TROUGH PUSHES ACROSS THE
SOUTHERN US. MODELS HAVE TRENDED FARTHER SOUTH WITH THIS SYSTEM
KEEPING EASTERN KENTUCKY ON THE VERY NORTHERN FRINGES OF THIS
SYSTEM. STILL LOTS OF DETAILS TO BE WORKED OUT WITH THIS
SYSTEM...BUT IT LOOKS LIKE ANY PRECIPITATION WOULD BE PRIMARILY
SNOW...ALTHOUGH NOT A LOT OF COLD AIR IN PLACE WITH THIS
SYSTEM...AND PRECIPITATION TYPE MIGHT BE DETERMINED BY PRECIPITATION
INTENSITY...WITH BETTER RATES YIELDING SNOW...AND LIGHTER RATES
BEING MORE RAIN OR DRIZZLE. WE WILL HAVE TO SEE IF THE SOUTHERN
TREND CONTINUES AS THIS COULD SHIFT PRECIPITATION SOUTH OF THE AREA
IF IT CONTINUES. THE WEATHER WILL FINALLY QUIET DOWN BY LATE
THURSDAY WITH A QUIETER...BUT STILL CHILLY END TO THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1244 AM EST SAT JAN 10 2015
HIGH PRESSURE WILL PROVIDE VFR CONDITIONS ACROSS THE AREA THROUGH THE
PERIOD. WNW WINDS OF AROUND 7 KTS...WITH A FEW STRAY GUSTS TO AROUND
15 KTS...WILL LINGER IN THE FAR EAST FOR A COUPLE MORE HOURS...BEFORE
DIMINISHING TO AROUND 5 KTS OR LESS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
103 AM EST SAT JAN 10 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION LATER TONIGHT WITH SOME
SNOW SHOWERS. A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE
REGION ON SATURDAY AND PASS EAST OF THE REGION SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
1 AM UPDATE: FCST HRLY TEMPS WERE UPDATE THRU THE REMAINDER OF THE
LATE NGT TO UNCHGD POSTED LOWS AT 7 AM. OTHERWISE...NO SIG CHGS
WERE NEEDED.
ORGNL DISC: SKIES HAD PARTLY CLEARED OUT THIS AFTERNOON ALLOWING
FOR TEMPS TO WARM SOME. IR SATELLITE IMAGERY SHOWED SOME
ENHANCEMENT BACK ACROSS WESTERN MAINE. THIS IS IN ASSOCIATION
W/THE PRE- FRONTAL BOUNDARY AHEAD OF THE ARCTIC FRONT. THIS
BOUNDARY HAS THE POTENTIAL FOR SETTING OFF SOME SNOW SHOWERS AND
PERHAPS A BRIEF SNOW SQUALL LATER THIS AFTERNOON INTO EARLY
EVENING. THE NAM AND HRRR 3KM MODEL PICK UP ON THIS FEATURE WELL.
SOUNDINGS SUPPORT SB CAPE OF 60-100 JOULES W/850-700MB LAPSE
RATES OF UP TO 7.0 C.KM. MOISTURE IS THERE THROUGH 700MBS. THIS
LENDS CREDENCE TO THE POTENTIAL OF SNOW SQUALL/HEAVY SNOW SHOWER
POTENTIALLY AND THE BTV SNOW SQUALL PARAMETER POINTS TO THIS AS
WELL. THE AREAS TO BE MOST AFFECTED APPEAR TO BE THE NORTH AND
WESTERN AREAS W/ACCUMULATIONS OF LESS THAN AN INCH. ELSEWHERE,
PARTIAL CLEARING AND COOLING DOWN AS THE ARCTIC FRONT MOVES IN
AFTER MIDNIGHT. THE 12Z UA SHOWED A 50 KT JET AT 700MBS IN LINE
W/THE FRONT. WINDS WILL SHIFT TO WEST AND PICK UP OVERNIGHT
W/GUSTS OF 25 MPH ESPECIALLY ACROSS THE NORTHERN AREAS IN
PROXIMITY OF THE 50KT JETLET. TEMPERATURES WILL FALL OFF SHARPLY
BY EARLY SATURDAY MORNING W/READINGS BELOW ZERO ACROSS THE NORTH
AND WEST W/SINGLE NUMBERS IN THE CENTRAL AND DOWNEAST REGIONS.
A COLD DAY ON SATURDAY W/HIGH PRES BRIEFLY BUILDING ACROSS THE
REGION. CLOUDS ARE EXPECTED TO BE BACK ON THE INCREASE SATURDAY
AFTERNOON AHEAD OF ANOTHER DISTURBANCE MOVING ACROSS QUEBEC. THIS
SYSTEM IS FAIRLY WEAK AND STARVED FOR SUBSTANTIAL MOISTURE.
THEREFORE, DECIDED TO STAY W/SLIGHT CHANCE FOR SOME SNOW SHOWERS
MAINLY ACROSS THE WEST AND NW SATURDAY AFTERNOON. DAYTIME
TEMPERATURES WILL STRUGGLE GET OUT OF THE SINGLE NUMBERS ACROSS
THE NORTHERN 1/2 OF THE CWA WHILE CENTRAL AND DOWNEAST WILL SEE
10-15 DEGREES FOR AFTERNOON MAX TEMPS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY/...
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM PORTION
OF THE FORECAST. A HIGH PRESSURE RIDGE WILL BE BUILT INTO SRN AND
ERN MAINE. A UPPER LEVEL LOW OVER NRN QUEBEC...WITH A TROUGH
EXTENDED SOUTH INTO SRN QUEBEC WILL AFFECT NRN MAINE EARLY IN THE
PERIOD. BY SUN MRNG THE TROUGH WILL MOVE EAST...THE HIGH PRESSURE
RIDGE WILL BUILD NORTH INTO CNTRL QUEBEC. A LOW OVER NRN LAKE
MICHIGAN...WITH A WARM FRONT EXTENDING EAST INTO ERN NY...WILL
MOVE EAST BY SUN EVNG. THE WARM FRONT WILL EXTEND INTO CNTRL ME.
THE UPPER LEVEL FLOW WILL KEEP THIS FRONT STATIONARY OVER SRN AND
CNTRL MAINE THROUGH THE END OF THE PERIOD. BY THE END OF THE
PERIOD AN UPPER TROUGH WILL PUSH INTO NW MAINE...TO BEGIN MOVING
THIS FRONT TO THE EAST OF THE AREA.
LOADED A BLEND OF GFS/NAM/GEM/ECMWF FOR HRLY T/DP/WND/SKY/POP.
LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS...ADDED 15 PERCENT
TO WNDS FOR GUSTS OVER LAND...30 PERCENT FOR GUSTS OVER THE
COASTAL WATERS. LOADED HPCGUIDE FOR QPF/ A BLEND OF GFS/ECMWF FOR
LAST 2 PERIODS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A COLD FRONT WILL BE EXTENDED ACROSS THE SE SECTION OF THE
STATE...SW ACROSS THE DOWNEAST COAST...THROUGH THE GULF OF MAINE.
A COLD HIGH PRESSURE RIDGE WILL BE BUILT INTO NW MAINE. BY EARLY
TUES MRNG THE FRONT WILL MOVE EAST OF THE AREA...THE HIGH WILL
BUILD ACROSS THE STATE. THE HIGH WILL SLOWLY RIDGE ACROSS THE
STATE CRESTING WED MRNG. A LOW WILL MOVE SE OUT OF WRN CANADA INTO
THE NRN GREAT LAKE EARLY THURS MRNG...WITH ITS WARM FRONT
EXTENDING TO NW MAINE. THE RIDGE WILL REMAIN ACROSS THE REGION AS
THIS LOW MOVES EAST INTO CNTRL QUEBEC. AT THIS TIME THE GFS AND
ECMWF ARE IN PRETTY GOOD AGREEMENT THAT THE LOW WILL MOVE INTO
EAST CNTRL QUEBEC EARLY FRI MRNG...AND THE COLD FRONT WILL MOVE
INTO NW MAINE AT THIS TIME. A SECOND LOW WILL DEVELOP ALONG THE
COAST OF THE CAROLINAS THURS MRNG...IT WILL MOVE NORTH TOWARD THE
ERN TIP OF NOVA SCOTIA BY FRI EVNG. A RIDGE OF HIGHER PRESSURE
WILL BUILD INTO MAINE...THAT WILL REMAIN THROUGH THE END OF THE
PERIOD.
LOADED THE SUPERBLEND THROUGH THE PERIOD...ADDED 15 PERCENT TO
WNDS FOR GUSTS OVER LAND...30 PERCENT FOR GUSTS OVER THE COASTAL
WATERS. LOADED NAWAVE 4 FOR SEAS IN THE COASTAL WATERS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR CONDITIONS EXPECTED INTO SATURDAY. A BRIEF PERIOD
OF MVFR THIS EVENING MAINLY FOR THE NORTHERN TERMINALS W/SOME SNOW
SHOWERS.
SHORT TERM: A FEW LINGERING SN SHWRS ACROSS NRN MAINE...MVFR
CONDITIONS EARLY NORTH...IMPROVING TO VFR BY NOON. VFR SOUTH. A
FEW SN SHWRS SOUTH SUNDAY...EXPECT CIGS TO REMAIN ABV 3K FT.
&&
.MARINE...
NEAR TERM: DECIDED TO HANG ON TO THE GALE WARNING THROUGH EARLY
EVENING AS GUSTS STILL 35+ KTS. EXPECTING THE WINDS TO DROP OFF
SCA LEVELS LATER THIS EVENING THROUGH THE OVERNIGHT. SEAS ARE
RUNNING VERY HIGH AT 14 TO 16 FT W/A PERIOD OF 10-11 SECONDS.
THESE ARE LARGE WAVES BUT THEY ARE FORECAST TO DROP OFF LATER THIS
EVENING INTO THE OVERNIGHT AS FLOW GOES OFFSHORE AND GRADIENT
FALLS BACK. IT IS MOST PROBABLE THAT THE FULL SCA COULD TRANSITION
TO A SCA FOR HAZARDS SEAS BY SATURDAY MORNING. THE NAM AND GFS
SHOW SUSTAINED WINDS DROPPING OFF BELOW 20 KTS BY SATURDAY
MORNING.
SHORT TERM: AN SCA FOR WNDS AND SEAS WILL BE REQUIRED THROUGH MID
DAY SUNDAY...OTHERWISE WINDS AND SEAS BELOW SCA.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORTON
LONG TERM...NORTON
AVIATION...VJN/NORTON
MARINE...VJN/NORTON
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
849 PM EST SUN JAN 11 2015
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE SOUTH OF THE MID-ATLANTIC
MONDAY. A WEAK COLD FRONT WILL CROSS THE AREA ON MONDAY. HIGH
PRESSURE WILL BUILD NORTH THROUGH MIDWEEK BEFORE LOW PRESSURE
MOVES OFF THE CAROLINA COAST THURSDAY NIGHT. HIGH PRESSURE THEN
PREVAILS INTO NEXT WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE IS WELL OFF THE EAST COAST THIS EVENING AND SFC PRESSURE
HAS BEEN DROPPING THIS EVENING. MOISTURE ADVECTION FROM THE SW HAS
BEEN ONGOING ALOFT AND THE COLUMN CONTINUES TO SATURATE PER THE
00Z IAD RAOB. ECHOS HAVE BEEN OBSERVED ON RADAR AS THE MID- LEVEL
MOISTURE MOVES INTO THE MID ATLANTIC FROM W TO E THIS EVENING. SFC
TEMPS HAVE DROPPED INTO THE LOW TO MID 30S AND UPPER 30S IN THE
CITY CENTERS. A LIGHT SOUTH WIND HAS LED TO DEWPTS SLOWLY CLIMBING
THIS EVENING. WET BULB SFC TEMPS ARE ALL BELOW ZERO THIS EVENING
DUE SUB FREEZING DEWPTS.
PRECIPITATION HAS BEGUN TO REACH THE GROUND ACROSS THE VA AND
POTOMAC HIGHLANDS THIS EVENING. REPORTS OF LIGHT FZRA RAIN HAVE
BEEN OBSERVED IN THIS AREA. RA HAS BEEN OBSERVED AT RAOBS ABOVE 32
DEG. THE FREEZING RAIN ADVISORY START TIME HAS BEEN CHANGED DUE TO
THE EARLIER ONSET OF FZRA AND MANY OBS AT OR BELOW 32 DEGREES.
THIS AREA CONSISTS OF ALONG AND WEST OF THE BLUE RIDGE AS WELL AS
ZONES FROM RAPPAHANNOCK NORTHWARD ALONG THE BLUE RIDGE AND
FREDERICK AND CARROLL COUNTIES IN MD. THE START TIME OF 10PM
CONTINUES FOR EVERYWHERE ELSE.
MAIN CONCERN THIS EVENING IS THE COVERAGE OF PRECIPIATION ON
RADAR AND TEMPERATURES/DEWPTS. HI RES AND DETERMINISTIC MODELS
CONTINUE TO SHOW PRECIPITATION STAYING LIGHT THROUGH MOST OF
TONIGHT AND NOT INTENSIFYING UNTIL THE EARLY MORNING HRS WHEN
MOISTURE ADVECTION FROM THE GULF REALLY INTENSIFIES ACROSS THE SE
US. THE COVERAGE IS EXPECTED TO BE SCATTERED AS SATURATION
CONTINUES TONIGHT AND FILL IN OVERNIGHT. FZRA CONTINUES AS THE
PRECIP TYPE THROUGH THIS EVENT ALTHOUGH SOME SLEET COULD MIX IN AT
ONSET TONIGHT. DEWPTS WILL CONTINUE TO RISE OVERNIGHT. THE LAMP
AND HRRR HAVE DEWPTS SLOWLY RISING COMPARED TO THE MOS AND NAM GUIDANCE
WHICH COULD RESULT IN A PROLONGED PERIOD OF WETBULBING INTO MONDAY
MORNING AND THEREFORE TEMPS COULD POTENTIALLY DROP LOWER. UPDATED
DEWPTS AND TEMPS WITH THIS TREND WITH ICE ACCUMULATION STAYING
LESS THAN A TENTH OF AN INCH FOR MOST AREAS. LOCATIONS NEAR THE
MASON DIXON LINE COULD SEE ISOLATED AMTS BETWEEN A TENTH AND TWO
TENTHS. A BRIEF LOOK AT MD ROAD TEMPS AND THEY HAVE DROPPED INTO
THE LOW 30S THIS EVENING. THE GROUND IS COLD IF NOT FROZEN FROM
PREVIOUS DAYS. UNTREATED SURFACES WILL BE ICY. USE CAUTION WHILE
TRAVELING TONIGHT AND MONDAY.
PREVIOUS DISCUSSION...
THE PRECIP WILL BE ALL RAIN DURING THE AFTERNOON AND BEGIN TO TAPER
OFF FROM WEST TO EAST. A STRONGER LLJ WILL MEAN PLENTY OF FORCING
AND MOISTURE FOR A GENERALLY STEADY RAIN...IN ADDITION TO HELPING
ELIMINATE ANY INVERSION AND THE TEMPERATURES RISE. MID 40S WILL BE
POSSIBLE IN THE SOUTHERN PART OF THE AREA...WITH THE NORTH STUCK IN
THE MID 30S.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
ANOTHER SURGE OF ARCTIC AIR WILL POUR INTO THE MIDDLE ATLANTIC
REGION MONDAY NIGHT. TEMPERATURES WILL DROP INTO THE TEENS IN MOST
AREAS WITH LOWER 20S IN THE BALTIMORE AND WASHINGTON DC METRO.
COLD HIGH PRESSURE WILL BUILD IN FOR TUESDAY AND TEMPERATURES WILL
NOT RISE ALL THAT MUCH DESPITE SUNSHINE. HIGH TEMPERATURES WILL ONLY
REACH THE MIDDLE TO UPPER 20S IN MOST LOCATIONS...PERHAPS LOW 30S
OVER SOUTHERN PORTIONS OF THE AREA. DRIER AIR WILL ALSO FILSTER IN
WITH THE HIGH PRESSURE RIDGE. HAVE REMOVED POPS FOR ALL AREAS
DURING THE DAY. ANOTHER COLD NIGHT EXPECTED TUESDAY NIGHT WITH
LOWS IN THE TEENS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE LONG TERM WILL BEGIN WITH THE MID-ATLANTIC IN A WEAK CAD
SITUATION DUE TO ELONGATED TROUGHING TO OUR NORTH...STRETCHING FROM
THE GREAT LAKES TO NEW ENGLAND...AND A BROAD AREA OF TROUGHING
LOCATED ALONG AND OFF THE SOUTHEAST COAST TO OUR SOUTH. WHILE MOST
OF THE PRECIPITATION ASSOCIATED WITH THE TROUGHING SHOULD STAY TO
OUR SOUTH THROUGH MIDWEEK...A WEAK SHORTWAVE CROSSING THE AREA DURING THE
DAYTIME WEDNESDAY WILL PROVIDE THE BEST CHANCE FOR PRECIP TO REACH
THE CWA. THUS CHANCE POPS MAINLY CONFINED TO THE SOUTHEASTERN SECTOR
OF THE CWA WEDNESDAY THROUGH THURSDAY. COLD AIR IN PLACE AT THE
SURFACE AND LACK OF STRONG WARM NOSE IN THE MID-LEVELS SHOULD ENSURE
THAT ANY PRECIP THAT DOES FALL WILL BE IN THE FORM OF SNOW...WITH
THE EXCEPTION OF THE FAR SOUTHERN PORTION OF THE CWA WHERE TEMPS
SHOULD BE WARM ENOUGH DURING THE DAYTIME THURSDAY TO PRODUCE PLAIN
RAIN. POPS CURRENTLY TOO LOW TO EXPECT ANY ACCUMULATION.
BROAD HIGH PRESSURE WILL BEGIN TO BUILD IN WEDNESDAY NIGHT BEFORE
ENCOMPASSING THE ENTIRE EASTERN CONUS BY FRIDAY NIGHT. UPPER LEVEL
RIDGING DURING THIS SAME TIME WILL LEAD TO PLENTY OF SUNSHINE AND
NEAR NORMAL TEMPS. WEAK SOUTHERLY FLOW WILL BEGIN TO DEVELOP AS THE
HIGH MOVES OFF THE COAST SATURDAY NIGHT AND SUNDAY WILL BRING ABOVE
NORMAL TEMPS IN LIGHT SOUTHERLY FLOW.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
LIGHT PRECIP WILL START THIS EVENING...WITH IFR CONDITIONS
GRADUALLY DEVELOPING BY DAYBREAK. COULD BE LOWER AT TIMES. A
PERIOD OF FZRA IS LIKELY AT THE TERMINALS...BUT TEMPERATURES WILL
BE VERY CLOSE TO FREEZING. IAD/MRB HAVE THE GREATEST CHANCE AT A
PROLONGED PERIOD OF ICING. THE THREAT FOR ICING WILL DECREASE
BETWEEN 12-15Z...WITH RAIN EXPECTED INTO THE AFTERNOON AND
CONTINUED IFR OR LOWER CONDITIONS. DRY NORTHERLY WINDS WILL BE
SLOW TO MOVE INTO THE TERMINALS MONDAY AFTERNOON/EVENING AND
THEREFORE KEPT MVFR CONDITIONS CLOSE TO 00Z TUESDAY. A COLD FRONT
WILL PASS THROUGH LATE IN THE DAY AND SHIFT LIGHT WINDS FROM S TO
NW. WINDS WILL GUST TO AROUND 20KTS MONDAY NIGHT BEHIND THE WIND SHIFT.
VFR CONDITIONS ARE EXPECTED TUESDAY INTO TUESDAY NIGHT. CONFIDENCE
IS LOW IN THE OCCURRENCE OF AVIATION HAZARDS THROUGH THE LONG TERM
PERIOD.
&&
.MARINE...
LIGHT SOUTHERLY WINDS WILL CONTINUE THROUGH TONIGHT AND MOST OF
MONDAY. AS A LOW PRESSURE SYSTEM APPROACHES THE WATER. PRECIPITATION
WILL MOVE IN LATE TONIGHT AND LAST THROUGH MONDAY. A PERIOD OF
FREEZING RAIN IS POSSIBLE...BUT A MAJORITY OF THE EVENT WILL BE
PLAIN RAIN ON THE WATERS. A COLD FRONT WILL MOVE THROUGH LATE IN THE
DAY AND SHIFT WINDS TO THE NW. NW WINDS WILL BECOME GUSTY ON THE
WATERS BEHIND THE FRONT AND A SCA IS IN EFFECT LATE MONDAY NIGHT
INTO TUESDAY. SCA MAY CONTINUE FOR PORTIONS OF THE WATERS INTO
TUESDAY NIGHT.
A SMALL CRAFT ADVISORY MAY ALSO BE NECESSARY INTO THE DAY
WEDNESDAY WITH BREEZY NORTHERLY WINDS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR DCZ001.
MD...FREEZING RAIN ADVISORY UNTIL 1 PM EST MONDAY FOR MDZ003>005-
501-502.
FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR MDZ011-013-
014-016>018-504-506-508.
FREEZING RAIN ADVISORY UNTIL 1 PM EST MONDAY FOR MDZ006-503-
505-507.
VA...FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR VAZ025>031-
040-501-503-504-507-508.
FREEZING RAIN ADVISORY UNTIL 1 PM EST MONDAY FOR VAZ505.
FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR VAZ036>039-
050>057-502-506.
WV...FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR WVZ050-055-
501>506.
FREEZING RAIN ADVISORY UNTIL 1 PM EST MONDAY FOR WVZ051>053.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM MONDAY TO 1 PM EST TUESDAY FOR
ANZ530>543.
&&
$$
SYNOPSIS...KRW
NEAR TERM...ADS/HAS
SHORT TERM...KRW
LONG TERM...CEB
AVIATION...ADS/CEB/KRW/HAS
MARINE...ADS/CEB/KRW/HAS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
334 PM EST SAT JAN 10 2015
.SHORT TERM...TONIGHT
SE MICHIGAN WILL EASE INTO MORE OF A QUASI-ZONAL SLIGHTLY CONFLUENT
MID LEVEL FLOW TONIGHT...BASE OF THE PREDOMINANT CENTRAL CANADIAN
TROUGH DICTATING CONDITIONS RECENTLY FINALLY RELEASING NORTH AND
EAST. A TRANSITION TOWARD LOW LEVEL SOUTH-SOUTHWEST FLOW WILL
INITIATE THE EARLY STAGES OF A PERIOD OF WARM AIR ADVECTION THAT
WILL PERSIST THROUGH THE REMAINDER OF THE WEEKEND. VERY LIMITED
MOISTURE RETURN NOTED UPSTREAM THIS AFTERNOON WITHIN THE ENSUING
BROADENING ISENTROPIC ASCENT TIED TO THIS PROCESS. DESPITE THE
GENERAL WARMING THROUGH THE THERMAL PROFILE...THERE WILL REMAIN SOME
PERPETUATION OF THE ONGOING WEAK LAKE MOISTURE FLUX. THIS WILL
CONTRIBUTE SLIGHTLY TO THE OVERALL MOISTURE QUALITY NORTH OF THE I-
69 CORRIDOR... PROVIDING A WINDOW FOR SOME ADDITIONAL LIGHT SNOW
SHOWER DEVELOPMENT TONIGHT. ELSEWHERE LITTLE MORE THAN
FLURRIES...RECENT NAM AND RAP SOUNDING DATA STILL LEAVE A HEALTHY
DRY LAYER WITHIN THE LOWEST 4000 FT THROUGH THE NIGHT.
EXISTING ENVIRONMENT REMAINS FAVORABLE FOR A GOOD NOCTURNAL COOLING
RESPONSE THIS EVENING...PARTICULARLY SOUTHERN/CENTRAL SECTIONS WHERE
SKIES ARE NOW CLEAR. THIS WILL BRING LOWS IN MANY LOCALES INTO THE
SINGLE DIGITS EARLY TONIGHT. A THICKENING CLOUD DECK AND SOME
INCREASE IN THE SOUTHWEST GRADIENT WILL THEN ALLOW TEMPERATURES TO
RISE GRADUALLY HEADING INTO THE EARLY MORNING PERIOD. TEMPERATURES
BACK INTO LOW-MID TEENS BY DAYBREAK.
&&
.LONG TERM...
THE SQUEEZE PLAY LOOKS TO BE ON LATE TOMORROW/TOMORROW NIGHT AS
UPPER WAVE AND ASSOCIATED MOISTURE OVER TEXAS MAKES A RUN NORTHEAST
TOWARD THE CENTRAL GREAT LAKES. AT THE SAME TIME...ANOTHER STRONG
NORTHERN STREAM TROUGH WILL BE DROPPING SOUTHEAST FROM CENTRAL
CANADA. THE TROUGH AXIS IS DISTINCTLY POSITIVELY TILTED AND WILL ACT
TO SHUNT/SHEAR OUT THE WAVE TO OUR SOUTH. REASONABLE AGREEMENT WITH
SUFFICIENT MOISTURE TRANSPORT SNEAKING ACROSS THE MICHIGAN BORDER TO
SUPPORT SOME LIGHT SNOW...AS 850-700 MB SPECIFIC HUMIDITY OF 3+ G/KG
SEEN REACHING THE M-59 CORRIDOR (REGIONAL GEM/GFS) OR EVEN AS FAR
NORTH AS THE I-69 CORRIDOR (NAM). THERMAL PROFILES ARE NOT IDEAL FOR
HIGH SNOW TO LIQUID RATIOS HOWEVER. FORCING FROM ISENTROPIC ASCENT
PROSPECTIVE IS NOT VERY AGGRESSIVE...AND BEST 850 MB FGEN LOOKS TO
BE OCCURRING AT OR JUST SOUTH OF THE MICHIGAN BORDER. NOT MUCH OF A
SURFACE REFLECTION AS WELL. THIS APPEARS TO BE A 1 TO 2 INCH
SNOWFALL FOR MOST OF SOUTHEAST MICHIGAN (FOCUSED M-59 SOUTH) BY THE
TIME THE SNOW ENDS MONDAY MORNING. 925 MB TEMPS PROGGED TO RISE TO
AROUND -5 C...BUT BOUNDARY LAYER DEPTH WILL FAIL TO REACH THIS
LEVEL...AND A SLOW GRIND INTO THE 20S FOR HIGHS EXPECTED
TOMORROW...WITH TEMPS HOLDING NEARLY STEADY SUNDAY EVENING/NIGHT
WITH THE INCREASE IN MOISTURE AND SNOW. SURPRISINGLY...NORTHERN
STREAM TROUGH LOOKS TO BE PROVIDING ONLY A GLANCING BLOW WITH THE
COLD AIR...AS 850 MB TEMPS PROGGED TO DROP INTO MID NEGATIVE TEENS
(PER 12Z EURO)...WITH DRY AIR/SUBSIDENCE WINNING OUT AT THIS
LEVEL...WITH RH DROPPING BELOW 50 PERCENT. STILL...WITH LONG FETCH
NORTHERLY FLOW DEVELOPING OVER LAKE HURON ON MONDAY...ENOUGH COLD
AIR/INSTABILITY/SATURATION AT THE 925 MB LEVEL TO GENERATE SOME SNOW
SHOWERS...PROBABLY BRUSHING THE LAKE HURON SHORELINE...BUT THE
SHALLOW NATURE IS EXPECTED TO LIMIT THE INTENSITY. LOW LEVEL WINDS
EVEN BECOME LIGHT NORTHEAST/ONSHORE BY MONDAY EVENING...BUT AGAIN
WITH THE AMOUNT OF DRY AIR AROUND AND SHALLOW NATURE...SHOULD LIMIT
ACTIVITY TO SCATTERED LIGHT SNOW SHOWERS...WITH JUST LIGHT
ACCUMULATIONS EXPECTED OVER THE NORTHERN THUMB REGION.
SPLIT FLOW ALOFT AND STABLE COLD ANTICYCLONE AT THE SURFACE WILL
LEAD TO COLD AND DRY WEATHER TUESDAY AND WEDNESDAY. WITH SNOW PACK
AND LIGHT WINDS WE COULD SEE TEMPS TANK PRETTY WELL TUESDAY NIGHT
PROVIDED ENOUGH CLEARING TAKES PLACE. THE COLD AIRMASS BEGINS TO
SCOUR OUT A BIT THURSDAY AS SURFACE PRESSURE GRADIENT TIGHTENS AHEAD
OF INCOMING UPPER TROUGH. FRONTAL PASSAGE LATE THURSDAY COULD LEAD
TO A FEW LIGHT SNOW SHOWERS...BUT IT WILL BE MOISTURE STARVED SO
WILL KEEP POPS OUT FOR NOW. PROGRESSIVE NATURE OF THE TROUGH WILL
ALLOW RISING HEIGHTS AND WARM AIR ADVECTION FRIDAY WITH TEMPERATURES
POSSIBLY FINALLY APPROACHING NORMAL BY NEXT WEEKEND.
&&
.MARINE...
COLD SOUTHWEST FLOW OVER THE CENTRAL GREAT LAKES THIS AFTERNOON
LEADING TO SUSTAINED WINDS OF 20 TO 30 KNOTS OVER LAKE HURON AS THE
AREA IS SANDWICHED IN BETWEEN LOW PRESSURE OVER ONTARIO AND HIGH
PRESSURE ALONG THE OHIO RIVER. A MARGINAL GUST TO GALES REMAIN
POSSIBLE FOR ANOTHER FEW HOURS AND WILL EXTEND HEAVY FREEZING
WARNING INTO THE EVENING...BUT THE HIGH WILL BE SLOWING EXITING
EAST...ALLOWING THE PRESSURE GRADIENT TO RELAX AS WE HEAD INTO
TONIGHT AND ESPECIALLY TOMORROW...AS ANOTHER ARCTIC COLD FRONT
APPROACHES. THIS FRONT WILL SLIDE THROUGH TOMORROW NIGHT INTO
MONDAY...LEADING TO NORTHERLY WINDS OVER LAKE HURON. THE ARCTIC AIR
IN THE WAKE OF THIS FRONT WILL BE MORE SHALLOW...THUS REDUCING
MIXING DEPTHS...WITH GUSTS ONLY UP TO 30 KNOTS EXPECTED DURING
MONDAY. WINDS WILL DECREASE RAPIDLY MONDAY EVENING/NIGHT AS STRONG
HIGH PRESSURE SETTLES OVER THE ENTIRE GREAT LAKES REGION.
&&
.AVIATION...ISSUED 1208 PM EST SAT JAN 10 2015
VERY DRY LOW LEVEL ENVIRONMENT AIDED BY A SHIFT IN WIND DIRECTION TO
SOUTH-SOUTHWEST WILL SUSTAIN A CLEAR SKY BELOW 5000 FT ACROSS ALL
BUT MBS THROUGH THIS EVENING. SOUTHWEST WINDS WILL BE GUSTY AT
TIMES INTO THE 20 KNOT RANGE. MID LEVEL CLOUD WILL INCREASE LATE
THIS EVENING AND EARLY TONIGHT AS WARMER AIR WORKS IN. LOWER LEVELS
REMAIN SUFFICIENTLY DRY AND WILL SUSTAIN A VFR CONDITION THROUGH
THIS TIME. MOISTURE DEPTH MAY IMPROVE ENOUGH TO SUPPORT AN EXPANSION
IN LOWER STRATUS INTO MBS BY LATE TONIGHT. THIS MAY ALSO YIELD A
FEW LIGHT SNOW SHOWERS ACROSS THIS CORRIDOR.
FOR DTW...JUST SOME POCKETS OF HIGH CLOUD THROUGH EARLY EVENING.
UPSTREAM OBSERVATIONS INDICATE THE INBOUND LOWER CLOUD DECK WILL
REMAIN ABOVE 5000 FT AS IT ENTERS THE TERMINAL AIRSPACE AFTER 00Z.
A FEW FLURRIES WITH THIS MOISTURE...NO IMPACT.
//DTW THRESHOLD PROBABILITIES...
* LOW CONFIDENCE IN CEILINGS LOWERING TO 5000 FT LATE TONIGHT AND ON
SUNDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING UNTIL 10 PM EST THIS EVENING FOR
LHZ362-363-462>464.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LHZ421-441.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...MR
LONG TERM....SF/DT
MARINE.......SF
AVIATION.....MR
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
321 PM EST SAT JAN 10 2015
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 320 PM EST SAT JAN 10 2015
A SLIGHT WARM UP IS ON THE WAY FOR THIS COMING WEEK. AS THE WARM
AIR STARTS TO MOVE IN TONIGHT THERE WILL BE A PERIOD OF LIGHT SNOW
SHOWERS...MOSTLY NORTH AND WEST OF GRAND RAPIDS. ANOTHER PERIOD OF
LIGHT SNOW WILL CROSS AREAS NEAR AND SOUTH OF INTERSTATE 96 SUNDAY
NIGHT AS THE COLD AIR ONCE AGAIN TRIES TO PUSH BACK SOUTHWARD. AS
OUR LAST POLAR ORIGIN HIGH OF THIS CURRENT WEATHER PATTERN MOVES
IN MONDAY SKIES WILL BE MOSTLY CLOUDY BUT WILL SEE CLEARING LATE
IN THE DAY. WITH THE HIGH OVERHEAD ON TUESDAY EXPECT MOSTLY SUNNY
SKIES AND VERY COLD TEMPERATURES FOR ONE MORE DAY. LOW WILL BE BELOW
ZERO IN MOST AREAS THAT NIGHT. BEY0ND THAT A SLOW WARM UP BEGINS. BY
NEXT SATURDAY WE MAY HAVE HIGH ABOVE FREEZING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 320 PM EST SAT JAN 10 2015
WE HAVE THE DEPARTING OF THE WEEK LONG COLD PATTERN UNDERWAY AS I
WRITE THIS. THIS WAS THE LONGEST STRING OF DAYS IN A ROW WITH
HIGHS BELOW 20 DEGREES IN GRAND RAPIDS SINCE THE MIDDLE OF
FEBRUARY IN 2007. THIS WILL BE HISTORY ON SUNDAY.
AS THE WARM AIR SURGES IN TONIGHT... EVEN WITH VERY FEEBLE
MOISTURE (PRECIPITABLE WATER SURGES TO A THIRD OF AN INCH/ 75TH
PERCENTILE)...SOME LIGHT SNOW IS EXPECTED WEST OF US-131 AND NORTH
OF GRAND RAPIDS DURING THE EARLY TO MID EVENING. THIS IS SHOWN BY
THE NAM... GFS... ECMWF... HRRR AND RAP MODELS TO VARYING DEGREES.
THERE IS A SURFACE BASED THERMAL BOUNDARY (20 DEGREE HOLLAND / 12AT
GRAND RAPIDS) CURRENTLY LOCATED FROM SOUTH HAVEN TO NEAR GRAND
RAPIDS TO NEAR MOUNT PLEASANT. THIS IS CURRENTLY FOCUSING SNOW
SHOWERS NEAR THE LAKE SHORE AND HELP FOCUS THE SNOW SHOWERS WITH
WARM AIR PUSH TONIGHT. ALSO HELPING THIS EVENT TOO IS THE LIFT
ASSOCIATED WITH THE ENTRANCE REGION TO DEPARTING UPPER LEVEL JET
CORE. THERE IS A 3 HOUR WINDOW WHERE OUR NORTHWEST CWA WILL HAVE
SOLID NEAR SATURATED AIR FROM AROUND 1000 FT AGL TO NEAR 10,000 FT
AGL. GIVEN HOW COLD IT IS...THAT IS MORE THAN ENOUGH TO LEAD TO
LIGHT SNOW SHOWERS.
ONCE THAT IS DONE SUNDAY NIGHT WE GET THE INTERPLAY OF THAT SAME
JET EXIT REGION WITH EXIT REGION OF JET CORE LIFTING NORTHWARD
FROM A SOUTHERN STREAM WAVE. THIS RESULTS IN A COUPLED JET AND THE
PRECIPIABLE WATER SURGES EVEN HIGHER TO NEARLY A HALF INCH WITH IS
ABOUT DOUBLE NORMAL. SO I AM THINKING LIGHT SNOW IS MORE THAN
LIKELY SOUTH OF INTERSTATE 96 SUNDAY NIGHT. IT IS MY EXPERIENCE
THAT THIS SORT OF EVENT NEARLY ALWAYS RESULTS IN MEASURABLE
PRECIPITATION SO I HAVE HIGH CONFIDENCE THERE WILL BE LIGHT SNOW
ALONG THE I-94 CORRIDOR SUNDAY NIGHT.
ONCE THAT IS DONE A JET CORE ON THE NORTHERN STREAM...DIVING DUE
SOUTHEAST FROM THE NORTHERN ARCTIC TOWARD HUDSON BY TUESDAY BRINGS
US OUR LAST SURGE OF VERY COLD AIR FOR TUESDAY. SINCE THE JET CORE
THIS TIME WILL BE WELL NORTH OF MICHIGAN THIS WILL BE SHALLOW COLD
AIR AND WINDS AT THE SURFACE WILL BE NORTHEAST SO WE GET TO SEE
MOSTLY SUNNY SKIES FOR A CHANGE! EVEN SO WITH SNOW ON THE GROUND
OVER MOST OF THE AREA IT WILL BE VERY COLD ONE LAST DAY.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 320 PM EST SAT JAN 10 2015
THE LONG TERM PORTION OF THE FCST LOOKS TO BE VERY QUIET FOR THIS
TIME OF THE YEAR. WE WILL START OFF WITH A COLD MORNING AT THE
BEGINNING OF THE PERIOD...AND THEN MODERATE AT THE END OF THE PERIOD.
WE WILL SEE A VERY COLD MORNING TUE MORNING AND AGAIN ON TUE
NIGHT/WED MORNING. HIGH PRESSURE PROVIDING A LIGHT GRADIENT AND
MAINLY CLEAR SKIES...WILL COMBINE WITH OUR SNOW PACK TO ALLOW MOST
TEMPS TO DROP BELOW ZERO TUE MORNING AND WED MORNING.
SOME MODERATION IN TEMPS WILL TAKE PLACE FOR WED AND THU AS RETURN
FLOW FROM THE WSW WILL SET UP OVER THE AREA. HIGH PRESSURE WILL DROP
SOUTH...AND WE WILL EVENTUALLY SEE A COLD FRONT TRY TO APPROACH THE
AREA FROM THE NW. TOUGH TO TELL HOW FAR SOUTH THIS FRONT WILL MAKE
IT...BUT IT COULD BRING A LOW CHC OF SNOW TO THE NRN PORTION OF THE
AREA ON THU. THE FRONTAL POSITION WILL ALSO DICTATE HOW WARM WE GET.
THE GFS TAKES IT A BIT FURTHER SOUTH WHILE THE EURO HOLDS IT UP
NORTH OF THE AREA.
THE BEST MODERATION IN TEMPS WILL COME AT THE END OF THE PERIOD.
AFTER THE THU SYSTEM MOVES BY...WE WILL GET BACK INTO A RETURN FLOW
PATTERN ONCE AGAIN. A ZONAL FLOW ALOFT WILL KEEP THE COLD AIR AND
WAVES OF LOW PRESSURE FAR ENOUGH NORTH TO KEEP OUR AREA DRY. WE
SHOULD SEE TEMPS AT LEAST GET INTO THE 30S BY NEXT SAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1238 PM EST SAT JAN 10 2015
CONDITIONS ARE RAPIDLY IMPROVING ACROSS THE AREA...ESPECIALLY
ALONG I-94 WHERE THE CLOUDS HAVE CLEARED OUT. SNOW SHOWERS ARE
DIMINISHING FOR THE TIME BEING FURTHER NORTH AT KMKG AND KGRR. WE
EXPECT THE LOW LEVEL CLEARING LINE TO SLOW UP AS IT APPROACHES
KGRR AND KMKG...SO MVFR WILL CONTINUE. HIGH CLOUDS ARE STREAMING IN...AND A
BATCH OF MID CLOUDS NEAR WI/MN WILL ZIP IN AFTER SUNSET. THESE
COMBINED WITH THE LOW CLOUDS WILL ALLOW FOR SOME SNOW BEGINNING
AROUND 22-00Z AT KMKG AND KGRR. THIS SNOW WILL DIMINISH GREATLY AS
THE LOW CLOUDS MOVE OUT AND VFR WILL TAKE OVER BY 06Z TONIGHT AND
CONTINUE THROUGH 18Z SUN WITH ONLY A FEW FLURRIES POSSIBLE.
&&
.MARINE...
ISSUED AT 320 PM EST SAT JAN 10 2015
I WILL ALLOW THE FREEZING SPRAY WARNING TO CONTINUE THROUGH 7 PM
AS WINDS ARE NEAR 25 KNOTS OVER THE WATER AND TEMPERATURES WERE IN
THE TEENS. SEEMS THAT TEMPERATURES WILL RISE INTO THE 20S IN THE
NEAR SHORE THIS EVENING ALLOWING US TO LET THE WARNING EXPIRE ON
TIME. WINDS WILL REMAIN STRONG ENOUGH FOR SMALL CRAFT INTO SUNDAY.
WE WILL HAVE TO WATCH TO SEE HOW MUCH THE ICE GROWS. THANKS TO
GLERL WE KNOW THERE IS ABOUT 22% ICE COVERAGE ON LAKE MICHIGAN NOW
AND THAT IF FORECAST TO INCREASE INTO THE MIDDLE OF NEXT WEEK.
&&
.HYDROLOGY...
ISSUED AT 320 PM EST SAT JAN 10 2015
LITTLE CHANGE SINCE YESTERDAY. CONTINUED THE FLOOD ADVISORY FOR THE
FLAT RIVER NEAR SMYRNA AS IT SHOULD REMAIN ABOVE BANKFULL INTO NEXT
WEEK. A COUPLE RIVERS REMAIN NEAR BUT UNDER BANKFULL AND WILL HAVE
TO BE MONITORED. FREEZE UP ICE JAMS MAY CAUSE FLUCTUATIONS IN RIVER
LEVELS INTO NEXT WEEK... BUT SERIOUS FLOODING IS NOT MUCH OF A
CONCERN UNTIL SNOWMELT AND ICE BREAKUP HAPPENS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LMZ844>849.
SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...CAS
MARINE...WDM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1114 AM CST SAT JAN 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST SAT JAN 10 2015
HIGH PRESSURE THIS MORNING IS ALREADY DOWN INTO THE MID MS/LOWER OH
RIVER VALLEYS. THIS HAS ALLOWED WINDS TO TURN OUT OF THE SW ACROSS
THE ENTIRE AREA OVERNIGHT. THESE SW WINDS REALLY PUT A DAMPER ON
TEMPERATURE DROPS OVERNIGHT...WHICH IN TURN HAS KEPT WIND CHILL
VALUES LARGELY IN THE IN THE -15 TO -20 RANGE...WELL SHORT OF THE
-25 ADVY CRITERIA. UNLESS SOMETHING DRASTIC CHANGES...WILL LIKELY
CANCEL MOST...IF NOT ALL OF THE ADVY WITH THE MORNING FORECAST
UPDATE.
BY THE AFTERNOON...A COLD FRONT CURRENTLY MOVING INTO NW NODAK WILL
BE WORKING ACROSS MN. WAA OUT AHEAD OF THE BOUNDARY WILL HELP SEND
TEMPERATURES BACK INTO THE DOUBLE DIGITS ABOVE ZERO...WITH SOME 20S
LIKELY DOWN ALONG THE I-90 CORRIDOR. FOR THIS FORECAST...STUCK
PRETTY CLOSE TO A RAW MODEL CONSENSUS AND BIAS CORRECTED MODEL
CONSENSUS FORECAST...WHICH HAVE BEEN THE DOMINATE PIECES OF GUIDANCE
OVER THE PAST WEEK IN THE VERIFICATION DEPARTMENT. NO PRECIPITATION
IS EXPECTED WITH THIS BOUNDARY...BUT IT DOES LOOK LIKE THERE WILL BE
ENOUGH MOISTURE ON THE NOSE OF THE LLJ TO GENERATE A FAIRLY
EXTENSIVE BANK OF CLOUDS IN THE 4K-6K FOOT RANGE BY THE AFTERNOON
ALONG AND AHEAD OF THE BOUNDARY...AS SEEN WITH HRRR CLOUD FORECAST.
TONIGHT...SAID BOUNDARY WILL SLIP SE OF THE MPX AREA...WITH LIGHT NW
WINDS OVERSPREADING THE AREA ONCE AGAIN. HOWEVER...CAA LOOKS PRETTY
MINIMAL BEHIND THE FRONT. IN ADDITION...WE LOOK TO HAVE EXTENSIVE
MID/UPPER LEVEL CLOUDS OVERNIGHT...SO TEMPERATURES CERTAINLY WILL
NOT CRASH. A LOOK AT VERIFICATION STATISTICS OVER THE PAST WEEK
SHOWS OUR LOW FORECASTS FOR 24 HOURS OUT HAVE HAD A PRETTY DISTINCT
COLD BIAS OF 3-6 DEGREES. DURING THIS TIME...THE BIAS CORRECTED
CONSENSUS GRIDS AND STRAIGHT RAW MODEL BLEND HAVE PERFORMED BEST FOR
LOWS...SO THIS FORECAST STAYED PRETTY CLOSE TO THOSE NUMBERS...WITH
LOWS TONIGHT CURRENTLY FORECAST TO REMAIN ABOVE -10F ACROSS THE
ENTIRE MPX AREA. WITH THAT SAID...WINDS WILL LIKELY GO CALM FROM SE
MN INTO WRN WI...AND IF THOSE MID/UPPER CLOUDS ARE NOT THERE...THEN
TEMPERATURES COULD EASILY END UP SEVERAL DEGREE COOLER THAN WHAT WE
CURRENTLY HAVE GIVEN THE POTENTIAL FOR STRONG RADIATIONAL COOLING
WITH CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CST SAT JAN 10 2015
NOT MUCH TO TALK ABOUT IN THE LONG TERM PORTION OF THE FORECAST...AS
WEAK RIDGING ALOFT BECOMES PREVALENT. THE MAIN ITEM OF INTEREST WILL
BE THE MODERATING TEMPERATURE TREND THAT WILL ENSUE...WITH READINGS
CLIMBING ABOVE MID JANUARY NORMALS TOWARD THE END OF THE UPCOMING
WEEK.
IN THE WAKE OF THE WEAK TROUGH...LOW LEVEL COLD AIR ADVECTION WILL
KEEP SUNDAY ON THE COOL SIDE OF NORMAL...WITH HIGHS RANGING FROM
THE SINGLE DIGITS /KAXN/ TO THE LOWER TEENS /KMSP-KEAU/. A
REINFORCEMENT OF COLD AIR/HIGH PRESSURE ARRIVES ON SUNDAY NIGHT
AND MONDAY. WIND CHILLS WILL THREATEN THE -25 WIND CHILL CRITERIA
BOTH SUNDAY NIGHT AND MONDAY NIGHT...ALTHOUGH BOTH NIGHTS LOOK
BORDERLINE FOR NEEDING AN ADVISORY.
TUESDAY BRINGS THE EXIT OF THE AFOREMENTIONED HIGH PRESSURE AREA
OFF TO THE SOUTHEAST...WITH WESTERLY FLOW AND WEAK RIDGING
ALLOWING FOR WARMING TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
BY WEDNESDAY...HIGHS IN THE 20S APPEAR ACHIEVABLE...WITH 30S
EXPECTED BY NEXT WEEKEND.
AS FAR AS PRECIPITATION IS CONCERNED...THE NEXT 7 DAYS APPEAR
DRY...WITH LONG RANGE MODELS NOT INDICATING ANY SYSTEMS ENTERING
THE AREA UNTIL AROUND THE 19TH-20TH OF JANUARY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1104 AM CST SAT JAN 10 2015
HIGH CONFIDENCE THAT LOW END VFR CIGS WILL CONTINUE THRU THE AFTN
ACROSS THE SE 1/3 OF MPX CWA. BASICALLY AFFECTING
KMSP/KRNH/KEAU...WITH ONLY SCATTERED CLDS OF 3-4K FOR
KRWF/KSTC/KAXN. AFT 00Z...VFR CONDS WILL PREVAIL WITH LIGHT S/SW
WINDS EARLY BECOMING NW/NNW OVERNIGHT/SUNDAY MORNING. THE NEXT
SYSTEM MOVING QUICKLY SE ACROSS THE NORTHERN PLAINS MAY ALLOW FOR
MVFR CIGS TO DEVELOP AT KAXN BY THE END OF THE TAF PERIOD. BUT
CONFIDENCE REMAINS LOW AT THIS TIME.
KMSP...
HIGH CONFIDENCE OF LOW END VFR CIGS /3.5-4K/ WILL CONTINUE THRU
21Z...THEN VFR CONDS THRU THE EVENING/OVERNIGHT HRS. WINDS WILL
CONTINUE FROM SSE ARND 6-8 KTS EARLY THIS AFTN...VEERING TO THE
SSW/SW BY THE MID/LATE AFTN...AND MORE NW THIS EVENING BUT BLW 7
KTS. CONFIDENCE REMAINS LOW ON MVFR CIGS DEVELOPING SUNDAY AFTN AS
THE NEXT SYSTEM AFFECT THE UPPER MIDWEST. WILL INTRODUCE SCT020
CIGS OF 4K AFT 18Z.
/OUTLOOK FOR KMSP/
SUN AFTN/EVENING...VFR. POSS MVFR CIGS EARLY. WINDS NW AT 5 KTS.
MON...VFR. WINDS N AT 5 KTS.
TUE...VFR. WINDS S AT 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
544 AM CST SAT JAN 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST SAT JAN 10 2015
HIGH PRESSURE THIS MORNING IS ALREADY DOWN INTO THE MID MS/LOWER OH
RIVER VALLEYS. THIS HAS ALLOWED WINDS TO TURN OUT OF THE SW ACROSS
THE ENTIRE AREA OVERNIGHT. THESE SW WINDS REALLY PUT A DAMPER ON
TEMPERATURE DROPS OVERNIGHT...WHICH IN TURN HAS KEPT WIND CHILL
VALUES LARGELY IN THE IN THE -15 TO -20 RANGE...WELL SHORT OF THE
-25 ADVY CRITERIA. UNLESS SOMETHING DRASTIC CHANGES...WILL LIKELY
CANCEL MOST...IF NOT ALL OF THE ADVY WITH THE MORNING FORECAST
UPDATE.
BY THE AFTERNOON...A COLD FRONT CURRENTLY MOVING INTO NW NODAK WILL
BE WORKING ACROSS MN. WAA OUT AHEAD OF THE BOUNDARY WILL HELP SEND
TEMPERATURES BACK INTO THE DOUBLE DIGITS ABOVE ZERO...WITH SOME 20S
LIKELY DOWN ALONG THE I-90 CORRIDOR. FOR THIS FORECAST...STUCK
PRETTY CLOSE TO A RAW MODEL CONSENSUS AND BIAS CORRECTED MODEL
CONSENSUS FORECAST...WHICH HAVE BEEN THE DOMINATE PIECES OF GUIDANCE
OVER THE PAST WEEK IN THE VERIFICATION DEPARTMENT. NO PRECIPITATION
IS EXPECTED WITH THIS BOUNDARY...BUT IT DOES LOOK LIKE THERE WILL BE
ENOUGH MOISTURE ON THE NOSE OF THE LLJ TO GENERATE A FAIRLY
EXTENSIVE BANK OF CLOUDS IN THE 4K-6K FOOT RANGE BY THE AFTERNOON
ALONG AND AHEAD OF THE BOUNDARY...AS SEEN WITH HRRR CLOUD FORECAST.
TONIGHT...SAID BOUNDARY WILL SLIP SE OF THE MPX AREA...WITH LIGHT NW
WINDS OVERSPREADING THE AREA ONCE AGAIN. HOWEVER...CAA LOOKS PRETTY
MINIMAL BEHIND THE FRONT. IN ADDITION...WE LOOK TO HAVE EXTENSIVE
MID/UPPER LEVEL CLOUDS OVERNIGHT...SO TEMPERATURES CERTAINLY WILL
NOT CRASH. A LOOK AT VERIFICATION STATISTICS OVER THE PAST WEEK
SHOWS OUR LOW FORECASTS FOR 24 HOURS OUT HAVE HAD A PRETTY DISTINCT
COLD BIAS OF 3-6 DEGREES. DURING THIS TIME...THE BIAS CORRECTED
CONSENSUS GRIDS AND STRAIGHT RAW MODEL BLEND HAVE PERFORMED BEST FOR
LOWS...SO THIS FORECAST STAYED PRETTY CLOSE TO THOSE NUMBERS...WITH
LOWS TONIGHT CURRENTLY FORECAST TO REMAIN ABOVE -10F ACROSS THE
ENTIRE MPX AREA. WITH THAT SAID...WINDS WILL LIKELY GO CALM FROM SE
MN INTO WRN WI...AND IF THOSE MID/UPPER CLOUDS ARE NOT THERE...THEN
TEMPERATURES COULD EASILY END UP SEVERAL DEGREE COOLER THAN WHAT WE
CURRENTLY HAVE GIVEN THE POTENTIAL FOR STRONG RADIATIONAL COOLING
WITH CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CST SAT JAN 10 2015
NOT MUCH TO TALK ABOUT IN THE LONG TERM PORTION OF THE FORECAST...AS
WEAK RIDGING ALOFT BECOMES PREVALENT. THE MAIN ITEM OF INTEREST WILL
BE THE MODERATING TEMPERATURE TREND THAT WILL ENSUE...WITH READINGS
CLIMBING ABOVE MID JANUARY NORMALS TOWARD THE END OF THE UPCOMING
WEEK.
IN THE WAKE OF THE WEAK TROUGH...LOW LEVEL COLD AIR ADVECTION WILL
KEEP SUNDAY ON THE COOL SIDE OF NORMAL...WITH HIGHS RANGING FROM
THE SINGLE DIGITS /KAXN/ TO THE LOWER TEENS /KMSP-KEAU/. A
REINFORCEMENT OF COLD AIR/HIGH PRESSURE ARRIVES ON SUNDAY NIGHT
AND MONDAY. WIND CHILLS WILL THREATEN THE -25 WIND CHILL CRITERIA
BOTH SUNDAY NIGHT AND MONDAY NIGHT...ALTHOUGH BOTH NIGHTS LOOK
BORDERLINE FOR NEEDING AN ADVISORY.
TUESDAY BRINGS THE EXIT OF THE AFOREMENTIONED HIGH PRESSURE AREA
OFF TO THE SOUTHEAST...WITH WESTERLY FLOW AND WEAK RIDGING
ALLOWING FOR WARMING TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
BY WEDNESDAY...HIGHS IN THE 20S APPEAR ACHIEVABLE...WITH 30S
EXPECTED BY NEXT WEEKEND.
AS FAR AS PRECIPITATION IS CONCERNED...THE NEXT 7 DAYS APPEAR
DRY...WITH LONG RANGE MODELS NOT INDICATING ANY SYSTEMS ENTERING
THE AREA UNTIL AROUND THE 19TH-20TH OF JANUARY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 523 AM CST SAT JAN 10 2015
FOLLOWED THE IDEA OF THE HRRR/RAP/NAM WITH STRATUS DEVELOPING
AHEAD OF A TROUGH THAT WILL BE MOVING ACROSS MN THIS AFTERNOON.
EXPECT THESE CLOUDS TO BE BETWEEN 4K AND 6K FEET...BUT SOME LOW
PROBS FOR MVFR CIGS DO SHOW UP ON THE SREF...SO WILL HAVE TO WATCH
THAT. LOOKS LIKE WI TERMINALS THOUGH WOULD HAVE THE BEST SHOT AT
MVFR CIGS. THE LOW CLOUDS WILL CLEAR OUT BEHIND THE TROUGH...BUT
WILL BE REPLACED BY HIGH CLOUDS SLOWLY DESCENDING INTO THE MID
LEVELS THROUGH THE NIGHT.
KMSP...HRRR HAS BEEN CONSISTENT ALL NIGHT IN DEVELOPING CIGS
AROUND 5K FEET BY THE AFTERNOON...SO BROUGHT IN A CIG AT 4K FT.
SOME CONCERN THESE COULD GET DOWN TO MVFR LEVELS...BUT IF THAT
HAPPENED...NOTHING LOWER THAN 2.5K FEET IS EXPECTED. NO OTHER
ISSUES ARE EXPECTED WITH THE REST OF THE TAF PERIOD OR ELEMENTS.
/OUTLOOK FOR KMSP/
SUN...VFR. WINDS NW AT 5 KTS.
MON...VFR. WINDS N AT 5 KTS.
TUE...VFR. WINDS S AT 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ041>045-
073>078-082>085-091>093.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
408 AM CST SAT JAN 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CST SAT JAN 10 2015
HIGH PRESSURE THIS MORNING IS ALREADY DOWN INTO THE MID MS/LOWER OH
RIVER VALLEYS. THIS HAS ALLOWED WINDS TO TURN OUT OF THE SW ACROSS
THE ENTIRE AREA OVERNIGHT. THESE SW WINDS REALLY PUT A DAMPER ON
TEMPERATURE DROPS OVERNIGHT...WHICH IN TURN HAS KEPT WIND CHILL
VALUES LARGELY IN THE IN THE -15 TO -20 RANGE...WELL SHORT OF THE
-25 ADVY CRITERIA. UNLESS SOMETHING DRASTIC CHANGES...WILL LIKELY
CANCEL MOST...IF NOT ALL OF THE ADVY WITH THE MORNING FORECAST
UPDATE.
BY THE AFTERNOON...A COLD FRONT CURRENTLY MOVING INTO NW NODAK WILL
BE WORKING ACROSS MN. WAA OUT AHEAD OF THE BOUNDARY WILL HELP SEND
TEMPERATURES BACK INTO THE DOUBLE DIGITS ABOVE ZERO...WITH SOME 20S
LIKELY DOWN ALONG THE I-90 CORRIDOR. FOR THIS FORECAST...STUCK
PRETTY CLOSE TO A RAW MODEL CONSENSUS AND BIAS CORRECTED MODEL
CONSENSUS FORECAST...WHICH HAVE BEEN THE DOMINATE PIECES OF GUIDANCE
OVER THE PAST WEEK IN THE VERIFICATION DEPARTMENT. NO PRECIPITATION
IS EXPECTED WITH THIS BOUNDARY...BUT IT DOES LOOK LIKE THERE WILL BE
ENOUGH MOISTURE ON THE NOSE OF THE LLJ TO GENERATE A FAIRLY
EXTENSIVE BANK OF CLOUDS IN THE 4K-6K FOOT RANGE BY THE AFTERNOON
ALONG AND AHEAD OF THE BOUNDARY...AS SEEN WITH HRRR CLOUD FORECAST.
TONIGHT...SAID BOUNDARY WILL SLIP SE OF THE MPX AREA...WITH LIGHT NW
WINDS OVERSPREADING THE AREA ONCE AGAIN. HOWEVER...CAA LOOKS PRETTY
MINIMAL BEHIND THE FRONT. IN ADDITION...WE LOOK TO HAVE EXTENSIVE
MID/UPPER LEVEL CLOUDS OVERNIGHT...SO TEMPERATURES CERTAINLY WILL
NOT CRASH. A LOOK AT VERIFICATION STATISTICS OVER THE PAST WEEK
SHOWS OUR LOW FORECASTS FOR 24 HOURS OUT HAVE HAD A PRETTY DISTINCT
COLD BIAS OF 3-6 DEGREES. DURING THIS TIME...THE BIAS CORRECTED
CONSENSUS GRIDS AND STRAIGHT RAW MODEL BLEND HAVE PERFORMED BEST FOR
LOWS...SO THIS FORECAST STAYED PRETTY CLOSE TO THOSE NUMBERS...WITH
LOWS TONIGHT CURRENTLY FORECAST TO REMAIN ABOVE -10F ACROSS THE
ENTIRE MPX AREA. WITH THAT SAID...WINDS WILL LIKELY GO CALM FROM SE
MN INTO WRN WI...AND IF THOSE MID/UPPER CLOUDS ARE NOT THERE...THEN
TEMPERATURES COULD EASILY END UP SEVERAL DEGREE COOLER THAN WHAT WE
CURRENTLY HAVE GIVEN THE POTENTIAL FOR STRONG RADIATIONAL COOLING
WITH CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CST SAT JAN 10 2015
NOT MUCH TO TALK ABOUT IN THE LONG TERM PORTION OF THE FORECAST...AS
WEAK RIDGING ALOFT BECOMES PREVALENT. THE MAIN ITEM OF INTEREST WILL
BE THE MODERATING TEMPERATURE TREND THAT WILL ENSUE...WITH READINGS
CLIMBING ABOVE MID JANUARY NORMALS TOWARD THE END OF THE UPCOMING
WEEK.
IN THE WAKE OF THE WEAK TROUGH...LOW LEVEL COLD AIR ADVECTION WILL
KEEP SUNDAY ON THE COOL SIDE OF NORMAL...WITH HIGHS RANGING FROM
THE SINGLE DIGITS /KAXN/ TO THE LOWER TEENS /KMSP-KEAU/. A
REINFORCEMENT OF COLD AIR/HIGH PRESSURE ARRIVES ON SUNDAY NIGHT
AND MONDAY. WIND CHILLS WILL THREATEN THE -25 WIND CHILL CRITERIA
BOTH SUNDAY NIGHT AND MONDAY NIGHT...ALTHOUGH BOTH NIGHTS LOOK
BORDERLINE FOR NEEDING AN ADVISORY.
TUESDAY BRINGS THE EXIT OF THE AFOREMENTIONED HIGH PRESSURE AREA
OFF TO THE SOUTHEAST...WITH WESTERLY FLOW AND WEAK RIDGING
ALLOWING FOR WARMING TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
BY WEDNESDAY...HIGHS IN THE 20S APPEAR ACHIEVABLE...WITH 30S
EXPECTED BY NEXT WEEKEND.
AS FAR AS PRECIPITATION IS CONCERNED...THE NEXT 7 DAYS APPEAR
DRY...WITH LONG RANGE MODELS NOT INDICATING ANY SYSTEMS ENTERING
THE AREA UNTIL AROUND THE 19TH-20TH OF JANUARY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1056 PM CST FRI JAN 9 2015
VFR THROUGHOUT THIS FCST PERIOD. WINDS TO REMAIN BELOW 10 KT AS
THEY GRADUALLY BACK FROM WLY TO SLY OVERNIGHT THRU TMRW MRNG
BEFORE GOING LGT/VRBL LATE DAY TMRW THEN NW TMRW EVE. MAINLY CLR
OVERNIGHT WITH SOME HIGH CLOUDS FILTERING IN DURG THE DAY TMRW AND
SOME FEW/SCT MIDLVL STRATOCU NOT AMOUNTING TO MUCH.
KMSP...VFR CONDS THROUGHOUT WITH NO SIGNIFICANT IMPACTS XPCTD.
/OUTLOOK FOR KMSP/
SUN...MVFR/IFR CIGS POSSIBLE WITH FLURRIES. WINDS N AT 5 KTS.
MON...VFR. WINDS N AT 5 KTS.
TUE...VFR. WINDS S AT 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ041>045-
073>078-082>085-091>093.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...LS
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1210 PM CST SAT JAN 10 2015
.UPDATE...
ISSUED AT 1209 PM CST SAT JAN 10 2015
SO FAR TODAY...ONLY MINOR TWEAKS MADE TO INHERITED FORECAST FOR
THIS AFTERNOON. NAMELY...NUDGED UP HIGH TEMPS ANOTHER 1-2 DEGREES
ALL AREAS GIVEN TRENDS SO FAR THIS MORNING...WITH MODEST LOW-LEVEL
WARM AIR ADVECTION ON SOUTHWESTERLY BREEZES SEEMINGLY ON ITS WAY
TO PUSHING MOST AREAS INTO THE 36-40 RANGE...AND MAYBE A GREATER
COVERAGE OF LOW 40S ROUGHLY SOUTHWEST OF AN ELWOOD-BELOIT LINE.
OTHERWISE...A GRADUAL DECREASE IN THE ONGOING GUSTY SOUTHWEST
WINDS WILL CONTINUE TAKING PLACE FROM WEST TO EAST AS THE
AFTERNOON WEARS ON...IN RESPONSE TO THE PRE-FRONTAL TROUGH AXIS
AHEAD OF THE WEAK COLD FRONT THAT WILL BE INVADING NORTHWEST ZONES
BY LATE AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CST SAT JAN 10 2015
WITH A DRY FORECAST...THE FOCUS IS ON TEMPERATURES. TODAY IS SHAPING
UP TO BE A WARMER DAY WITH RISING HEIGHTS IN NORTHWEST FLOW ALOFT AS
THE EASTERN TROUGH LIFTS OUT...WITH FLOW TRANSITIONING MORE ZONAL
TONIGHT AS THE NEXT LOBE OF ENERGY ON THE BACK SIDE OF THE HUDSON
BAY UPPER LOW TRANSLATES SOUTHEAST AND SENDS A COOL FRONTAL BOUNDARY
SOUTH THRU OUR REGION TONIGHT.
WARM AIR ADVECTION HAS ALREADY KICKED IN EARLY THIS MORNING AND
TEMPERATURES HAVE ALREADY RISEN 3-5F...AIDED BY AN INCREASING LLVL
JET. MODELS VARY WITH THE EXTENT OF CLOUD COVER TODAY AND SO FAR
MODELS HAVE INDICATED MORE EXTENSIVE LOW CLOUDS THAN WHAT IS
REALITY ATTM. DO EXPECT SOME CLOUDS AROUND TODAY...BUT CLOUDS
SHOULD BE VARIABLE ENOUGH FOR A MIX OF SUN/CLOUDS AND TEMPS SHOULD
SEE A NICE REBOUND AHEAD OF THE APPROACHING BOUNDARY. HAVE
FOLLOWED CLOSER TO THE RAP FOR TEMPS TODAY WHICH INDICATE HIGHS
RANGING FROM THE MID/UPPER 30S TO THE LOWER 40S. THE NAM IS
HOLDING ONTO TOO MUCH SNOWCOVER VS COOP OBS AND VIS SATELLITE
IMAGERY FROM FRI AFTN...AND INITIALIZED WITH SNOWFALL ACROSS
PRETTY MUCH OUR ENTIRE CWA WITH SNOW DEPTHS IN EXCESS OF 6 INCHES
ACROSS OUR NORTHERN ZONES. GIVEN THE POOR INITIALIZATION...DID NOT
UTILIZE NAM FOR TEMPS.
THE SURFACE COLD FRONTAL BOUNDARY ADVANCES SOUTH THIS EVENING AND
TONIGHT AND IS SLOW TO PROGRESS THRU OUR SOUTHERN CWA. OF
INTEREST IS THAT THE SREF INDICATES HIGH PROBABILITIES FOR VSBYS
RESTRICTIONS THIS EVENING/TONIGHT ACROSS OUR SOUTHERN/SOUTHWEST
ZONES AHEAD OF THE BOUNDARY. THIS AREA COINCIDES WITH HIGHER MODEL
DP PROGS AND MAY BE THE RESULT OF EXPECTED SNOW MELT DUE TO MODEL
SNOWPACK INITIALIZATION. WITH MODEL INCONSISTENCIES IN THE
POTENTIAL FOR THIS...HAVE NOT MENTIONED ANY FOG IN FORECAST AND
THIS WILL NEED TO BE MONITORED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 322 AM CST SAT JAN 10 2015
REALLY HASNT BEEN ANY NOTABLE CHANGES IN THE MODELS LOOKING THROUGH
THE LONG TERM...STILL IN PRETTY GOOD AGREEMENT AT THE START OF THE
PERIOD SUNDAY MORNING. EXPECTING TO SEE GENERALLY ZONAL FLOW IN
PLACE IN THE UPPER LEVELS ACROSS THE REGION...WITH A FEW
DISTURBANCES AFFECTING THE WRN HALF OF THE CONUS...ONE OF WHICH
LOOKS TO BE EMERGING ONTO THE PLAINS OUT OF ERN CO. THIS DISTURBANCE
IS EXPECTED TO MAINLY PASS THROUGH TO OUR S ACROSS KS...WITH MUCH OF
THE MODELS SUPPORTING THE PRECIP-FREE FORECAST. CERTAINLY NOT 100
PERCENT CONFIDENT IN THAT...MAINLY DUE TO THE GFS SPITTING OUT A
LITTLE LIGHT QPF...BUT UNTIL THERE IS MORE MODELS TRENDING THAT WAY
WILL KEEP THE FORECAST AS IS. AT THE SFC...A COLD FRONT WILL HAVE
PUSHED ITS WAY THROUGH A MAJORITY OF THE CWA BY SUNRISE SUNDAY...BUT
WITH THE PARENT HIGH WELL NORTH OF THE AREA...NOT A BIG PUSH OF
STRONGER NORTH WINDS ACCOMPANYING THE FRONT. WILL BE A COLDER AIR
MASS BUILDING IN...AND FORECAST HIGHS CURRENTLY RANGE FROM NEAR 20
IN THE NORTH TO NEAR 30 IN THE SOUTH.
SUNDAY NIGHT AND MONDAY...A STRONGER SHORTWAVE TROUGH ASSOCIATED
WITH LOW PRESSURE NEAR THE HUDSON BAY AREA WILL PUSH SOUTH OUT OF
CENTRAL CANADA AND THROUGH NRN SECTIONS OF THE CONUS /AND EVENTUALLY
EAST/. THE PRIMARY PUSH LOOKS TO COME SUNDAY NIGHT...BRINGING A
REINFORCING SHOT OF NRLY WINDS AND COLDER AIR. WONT BE A BIG SHOT OF
WINDS...WITH SPEEDS JUST TOPPING OUT IN THE 10 TO 15 MPH RANGE. SFC
HIGH PRESSURE WILL STILL BE CENTERED OFF TO THE N/NE OF THE
CWA...BUT CLOSER THAN IT WAS SUNDAY...WITH THE ASSOCIATED RIDGE AXIS
EXTENDING SW THROUGH THE AREA. AT THIS POINT...MONDAY IS FORECAST TO
BE THE COLDEST DAY OF THE LONG TERM PERIOD...WITH HIGHS TOPPING OUT
IN THE MID TEENS NORTH TO NEAR 20 SOUTH. AS FAR AS PRECIPITATION
GOES...THAT SECOND PUSH OF THE FRONT WITH THIS DISTURBANCE LOOKS TO
KEEP THE BETTER CHANCES JUST OFF TO THE S/SE OF THE CWA...BUT WILL
BE SOMETHING FOR UPCOMING SHIFTS TO MONITOR AS IT WOULDNT TAKE A
SIGNIFICANT SHIFT BACK TO THE NW FOR OUR AREA TO POTENTIALLY BE
AFFECTED.
LOOKING TO THE TUES/TUES NIGHT TIME FRAME...MODELS ARE IN PRETTY
GOOD AGREEMENT SHOWING A PIECE OF UPPER LEVEL ENERGY DIGGING ITS WAY
SOUTH INTO THE ROCKIES MON/MON NIGHT...AND BY 12Z TUESDAY IS LOCATED
ROUGHLY OVER THE 4 CORNERS REGION. IT CONTINUES TO SHIFT EAST DURING
THE DAY...AND TUESDAY NIGHT MAY SWING CLOSE ENOUGH TO THE SRN
PORTIONS OF THE CWA TO BRING SOME SNOW CHANCES. THERE ARE STILL
PLENTY OF DIFFERENCES TO BE WORKED OUT WITH THE STRENGTH/TIMING/PATH
OF THIS SYSTEM...BUT KEPT POPS ON THE LOW SIDE...AS IN GENERAL THE
BRUNT OF IT SHOULD PASS THROUGH THE SRN PLAINS. NOT CONFIDENT IN HOW
IT WILL EVOLVE SO KEPT POPS CONFINED TO THAT 12HR PERIOD OF 00-12Z
WEDNESDAY. TUESDAY SHOULD SEE A REBOUND IN TEMPS COMPARED TO
MONDAY...AND HIGHS IN THE LOW/MID 20S ARE FORECAST.
WEDNESDAY THROUGH FRIDAY...THE WARMING TREND IN TEMPERATURES LOOKS
TO CONTINUE...WITH DRY CONDITIONS REMAINING IN THE FORECAST...AS
MORE NORTHWESTERLY FLOW DEVELOPS IN THE UPPER LEVELS THANKS TO AT
LEAST BRIEF RIDGING OVER THE WRN CONUS. MODELS ARE IN DECENT
AGREEMENT SHOWING MODERATING TEMPS ALOFT THROUGH THE FINAL 3 DAYS OF
THE PERIOD...WITH THE POTENTIAL OF DOWNSLOPING W/NW WINDS MAINLY
THURSDAY AND FRIDAY. BUMPED UP HIGHS A TOUCH FOR THOSE 2 DAYS FROM
SUPERBLEND GRIDS...WITH TEMPS RANGING FROM UPPER 20S/LOW 30S ON WED
TO LOWER/MID 40S FOR FRIDAY.
&&
.AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1209 PM CST SAT JAN 10 2015
AT LEAST FOR NOW...WILL CONTINUE TO ADVERTISE BOTH VFR/CEILING
THROUGHOUT THE PERIOD AND ALTHOUGH CONFIDENCE REMAINS QUITE HIGH
IN THIS PROSPECT THROUGH AT LEAST THE FIRST 6 HOURS...THERE ARE
SOME QUESTION MARKS REGARDING WHAT HAPPENS THIS EVENING/TONIGHT
BEHIND A WEAK COLD FRONT AS SOME MODELS/GUIDANCE SUGGEST THE
DEVELOPMENT OF A LOW-END MVFR AND MAYBE EVEN IFR CEILING AND/OR
SOME REDUCED VISIBILITY IN AT LEAST LIGHT FOG DEVELOPMENT. DESPITE
THESE POSSIBILITIES...AM STILL A BIT SKEPTICAL THAT THESE LOW
CEILINGS/FOG WILL ACTUALLY MATERIALIZE...AND EVEN IF THEY
DO...THEY WOULD SEEM TO FAVOR AREAS SLIGHTLY SOUTH OF THE
TERMINALS. AS A RESULT OF THIS THINKING...HAVE OPTED TO KEEP IT
VFR FOR NOW...BUT STILL HINTING AT THE SUB-VFR POSSIBILITIES WITH
A MENTION OF LOW-END VFR VISIBILITY AND "SCT010" CLOUDS THROUGH
MUCH OF THE NIGHT INTO SUNDAY MORNING. HOPEFULLY BY THE NEXT TAF
CYCLE FORECASTER CONFIDENCE WILL INCREASE A BIT IN WHETHER OR NOT
SUB-VFR CONDITIONS WARRANT INCLUSION. AS FOR SURFACE
WIND...INITIALLY GUSTY SOUTHWEST WIND RIGHT AWAY THIS AFTERNOON
WILL SLOWLY DECREASE WITHIN A FEW HOURS...AND THEN TRANSITION TO
FAIRLY LIGHT AND NORTHERLY BREEZES BEHIND A WEAK COLD FRONT THIS
EVENING/TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...FAY
LONG TERM...ADP
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
538 AM CST SAT JAN 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CST SAT JAN 10 2015
WITH A DRY FORECAST...THE FOCUS IS ON TEMPERATURES. TODAY IS SHAPING
UP TO BE A WARMER DAY WITH RISING HEIGHTS IN NORTHWEST FLOW ALOFT AS
THE EASTERN TROUGH LIFTS OUT...WITH FLOW TRANSITIONING MORE ZONAL
TONIGHT AS THE NEXT LOBE OF ENERGY ON THE BACK SIDE OF THE HUDSON
BAY UPPER LOW TRANSLATES SOUTHEAST AND SENDS A COOL FRONTAL BOUNDARY
SOUTH THRU OUR REGION TONIGHT.
WARM AIR ADVECTION HAS ALREADY KICKED IN EARLY THIS MORNING AND
TEMPERATURES HAVE ALREADY RISEN 3-5F...AIDED BY AN INCREASING LLVL
JET. MODELS VARY WITH THE EXTENT OF CLOUD COVER TODAY AND SO FAR
MODELS HAVE INDICATED MORE EXTENSIVE LOW CLOUDS THAN WHAT IS
REALITY ATTM. DO EXPECT SOME CLOUDS AROUND TODAY...BUT CLOUDS
SHOULD BE VARIABLE ENOUGH FOR A MIX OF SUN/CLOUDS AND TEMPS SHOULD
SEE A NICE REBOUND AHEAD OF THE APPROACHING BOUNDARY. HAVE
FOLLOWED CLOSER TO THE RAP FOR TEMPS TODAY WHICH INDICATE HIGHS
RANGING FROM THE MID/UPPER 30S TO THE LOWER 40S. THE NAM IS
HOLDING ONTO TOO MUCH SNOWCOVER VS COOP OBS AND VIS SATELLITE
IMAGERY FROM FRI AFTN...AND INITIALIZED WITH SNOWFALL ACROSS
PRETTY MUCH OUR ENTIRE CWA WITH SNOW DEPTHS IN EXCESS OF 6 INCHES
ACROSS OUR NORTHERN ZONES. GIVEN THE POOR INITIALIZATION...DID NOT
UTILIZE NAM FOR TEMPS.
THE SURFACE COLD FRONTAL BOUNDARY ADVANCES SOUTH THIS EVENING AND
TONIGHT AND IS SLOW TO PROGRESS THRU OUR SOUTHERN CWA. OF
INTEREST IS THAT THE SREF INDICATES HIGH PROBABILITIES FOR VSBYS
RESTRICTIONS THIS EVENING/TONIGHT ACROSS OUR SOUTHERN/SOUTHWEST
ZONES AHEAD OF THE BOUNDARY. THIS AREA COINCIDES WITH HIGHER MODEL
DP PROGS AND MAY BE THE RESULT OF EXPECTED SNOW MELT DUE TO MODEL
SNOWPACK INITIALIZATION. WITH MODEL INCONSISTENCIES IN THE
POTENTIAL FOR THIS...HAVE NOT MENTIONED ANY FOG IN FORECAST AND
THIS WILL NEED TO BE MONITORED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 322 AM CST SAT JAN 10 2015
REALLY HASNT BEEN ANY NOTABLE CHANGES IN THE MODELS LOOKING THROUGH
THE LONG TERM...STILL IN PRETTY GOOD AGREEMENT AT THE START OF THE
PERIOD SUNDAY MORNING. EXPECTING TO SEE GENERALLY ZONAL FLOW IN
PLACE IN THE UPPER LEVELS ACROSS THE REGION...WITH A FEW
DISTURBANCES AFFECTING THE WRN HALF OF THE CONUS...ONE OF WHICH
LOOKS TO BE EMERGING ONTO THE PLAINS OUT OF ERN CO. THIS DISTURBANCE
IS EXPECTED TO MAINLY PASS THROUGH TO OUR S ACROSS KS...WITH MUCH OF
THE MODELS SUPPORTING THE PRECIP-FREE FORECAST. CERTAINLY NOT 100
PERCENT CONFIDENT IN THAT...MAINLY DUE TO THE GFS SPITTING OUT A
LITTLE LIGHT QPF...BUT UNTIL THERE IS MORE MODELS TRENDING THAT WAY
WILL KEEP THE FORECAST AS IS. AT THE SFC...A COLD FRONT WILL HAVE
PUSHED ITS WAY THROUGH A MAJORITY OF THE CWA BY SUNRISE SUNDAY...BUT
WITH THE PARENT HIGH WELL NORTH OF THE AREA...NOT A BIG PUSH OF
STRONGER NORTH WINDS ACCOMPANYING THE FRONT. WILL BE A COLDER AIR
MASS BUILDING IN...AND FORECAST HIGHS CURRENTLY RANGE FROM NEAR 20
IN THE NORTH TO NEAR 30 IN THE SOUTH.
SUNDAY NIGHT AND MONDAY...A STRONGER SHORTWAVE TROUGH ASSOCIATED
WITH LOW PRESSURE NEAR THE HUDSON BAY AREA WILL PUSH SOUTH OUT OF
CENTRAL CANADA AND THROUGH NRN SECTIONS OF THE CONUS /AND EVENTUALLY
EAST/. THE PRIMARY PUSH LOOKS TO COME SUNDAY NIGHT...BRINGING A
REINFORCING SHOT OF NRLY WINDS AND COLDER AIR. WONT BE A BIG SHOT OF
WINDS...WITH SPEEDS JUST TOPPING OUT IN THE 10 TO 15 MPH RANGE. SFC
HIGH PRESSURE WILL STILL BE CENTERED OFF TO THE N/NE OF THE
CWA...BUT CLOSER THAN IT WAS SUNDAY...WITH THE ASSOCIATED RIDGE AXIS
EXTENDING SW THROUGH THE AREA. AT THIS POINT...MONDAY IS FORECAST TO
BE THE COLDEST DAY OF THE LONG TERM PERIOD...WITH HIGHS TOPPING OUT
IN THE MID TEENS NORTH TO NEAR 20 SOUTH. AS FAR AS PRECIPITATION
GOES...THAT SECOND PUSH OF THE FRONT WITH THIS DISTURBANCE LOOKS TO
KEEP THE BETTER CHANCES JUST OFF TO THE S/SE OF THE CWA...BUT WILL
BE SOMETHING FOR UPCOMING SHIFTS TO MONITOR AS IT WOULDNT TAKE A
SIGNIFICANT SHIFT BACK TO THE NW FOR OUR AREA TO POTENTIALLY BE
AFFECTED.
LOOKING TO THE TUES/TUES NIGHT TIME FRAME...MODELS ARE IN PRETTY
GOOD AGREEMENT SHOWING A PIECE OF UPPER LEVEL ENERGY DIGGING ITS WAY
SOUTH INTO THE ROCKIES MON/MON NIGHT...AND BY 12Z TUESDAY IS LOCATED
ROUGHLY OVER THE 4 CORNERS REGION. IT CONTINUES TO SHIFT EAST DURING
THE DAY...AND TUESDAY NIGHT MAY SWING CLOSE ENOUGH TO THE SRN
PORTIONS OF THE CWA TO BRING SOME SNOW CHANCES. THERE ARE STILL
PLENTY OF DIFFERENCES TO BE WORKED OUT WITH THE STRENGTH/TIMING/PATH
OF THIS SYSTEM...BUT KEPT POPS ON THE LOW SIDE...AS IN GENERAL THE
BRUNT OF IT SHOULD PASS THROUGH THE SRN PLAINS. NOT CONFIDENT IN HOW
IT WILL EVOLVE SO KEPT POPS CONFINED TO THAT 12HR PERIOD OF 00-12Z
WEDNESDAY. TUESDAY SHOULD SEE A REBOUND IN TEMPS COMPARED TO
MONDAY...AND HIGHS IN THE LOW/MID 20S ARE FORECAST.
WEDNESDAY THROUGH FRIDAY...THE WARMING TREND IN TEMPERATURES LOOKS
TO CONTINUE...WITH DRY CONDITIONS REMAINING IN THE FORECAST...AS
MORE NORTHWESTERLY FLOW DEVELOPS IN THE UPPER LEVELS THANKS TO AT
LEAST BRIEF RIDGING OVER THE WRN CONUS. MODELS ARE IN DECENT
AGREEMENT SHOWING MODERATING TEMPS ALOFT THROUGH THE FINAL 3 DAYS OF
THE PERIOD...WITH THE POTENTIAL OF DOWNSLOPING W/NW WINDS MAINLY
THURSDAY AND FRIDAY. BUMPED UP HIGHS A TOUCH FOR THOSE 2 DAYS FROM
SUPERBLEND GRIDS...WITH TEMPS RANGING FROM UPPER 20S/LOW 30S ON WED
TO LOWER/MID 40S FOR FRIDAY.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 512 AM CST SAT JAN 10 2015
ALTHOUGH SFC WINDS HAVE BEGUN TO INCREASE...A PERIOD OF LLWS IS
FORECAST THIS MORNING AS WINDS RAPIDLY INCREASE ABOVE THE SFC DUE
TO A STRONG LLVL JET. CLOUDS WILL BE VARIABLE TODAY AND PRIMARILY
AT HIGH LEVELS. A COLD FRONTAL BOUNDARY WILL CROSS THE TERMINAL
TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...ADP
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
340 AM CST SAT JAN 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CST SAT JAN 10 2015
WITH A DRY FORECAST...THE FOCUS IS ON TEMPERATURES. TODAY IS SHAPING
UP TO BE A WARMER DAY WITH RISING HEIGHTS IN NORTHWEST FLOW ALOFT AS
THE EASTERN TROUGH LIFTS OUT...WITH FLOW TRANSITIONING MORE ZONAL
TONIGHT AS THE NEXT LOBE OF ENERGY ON THE BACK SIDE OF THE HUDSON
BAY UPPER LOW TRANSLATES SOUTHEAST AND SENDS A COOL FRONTAL BOUNDARY
SOUTH THRU OUR REGION TONIGHT.
WARM AIR ADVECTION HAS ALREADY KICKED IN EARLY THIS MORNING AND
TEMPERATURES HAVE ALREADY RISEN 3-5F...AIDED BY AN INCREASING LLVL
JET. MODELS VARY WITH THE EXTENT OF CLOUD COVER TODAY AND SO FAR
MODELS HAVE INDICATED MORE EXTENSIVE LOW CLOUDS THAN WHAT IS
REALITY ATTM. DO EXPECT SOME CLOUDS AROUND TODAY...BUT CLOUDS
SHOULD BE VARIABLE ENOUGH FOR A MIX OF SUN/CLOUDS AND TEMPS SHOULD
SEE A NICE REBOUND AHEAD OF THE APPROACHING BOUNDARY. HAVE
FOLLOWED CLOSER TO THE RAP FOR TEMPS TODAY WHICH INDICATE HIGHS
RANGING FROM THE MID/UPPER 30S TO THE LOWER 40S. THE NAM IS
HOLDING ONTO TOO MUCH SNOWCOVER VS COOP OBS AND VIS SATELLITE
IMAGERY FROM FRI AFTN...AND INITIALIZED WITH SNOWFALL ACROSS
PRETTY MUCH OUR ENTIRE CWA WITH SNOW DEPTHS IN EXCESS OF 6 INCHES
ACROSS OUR NORTHERN ZONES. GIVEN THE POOR INITIALIZATION...DID NOT
UTILIZE NAM FOR TEMPS.
THE SURFACE COLD FRONTAL BOUNDARY ADVANCES SOUTH THIS EVENING AND
TONIGHT AND IS SLOW TO PROGRESS THRU OUR SOUTHERN CWA. OF
INTEREST IS THAT THE SREF INDICATES HIGH PROBABILITIES FOR VSBYS
RESTRICTIONS THIS EVENING/TONIGHT ACROSS OUR SOUTHERN/SOUTHWEST
ZONES AHEAD OF THE BOUNDARY. THIS AREA COINCIDES WITH HIGHER MODEL
DP PROGS AND MAY BE THE RESULT OF EXPECTED SNOW MELT DUE TO MODEL
SNOWPACK INITIALIZATION. WITH MODEL INCONSISTENCIES IN THE
POTENTIAL FOR THIS...HAVE NOT MENTIONED ANY FOG IN FORECAST AND
THIS WILL NEED TO BE MONITORED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 322 AM CST SAT JAN 10 2015
REALLY HASNT BEEN ANY NOTABLE CHANGES IN THE MODELS LOOKING THROUGH
THE LONG TERM...STILL IN PRETTY GOOD AGREEMENT AT THE START OF THE
PERIOD SUNDAY MORNING. EXPECTING TO SEE GENERALLY ZONAL FLOW IN
PLACE IN THE UPPER LEVELS ACROSS THE REGION...WITH A FEW
DISTURBANCES AFFECTING THE WRN HALF OF THE CONUS...ONE OF WHICH
LOOKS TO BE EMERGING ONTO THE PLAINS OUT OF ERN CO. THIS DISTURBANCE
IS EXPECTED TO MAINLY PASS THROUGH TO OUR S ACROSS KS...WITH MUCH OF
THE MODELS SUPPORTING THE PRECIP-FREE FORECAST. CERTAINLY NOT 100
PERCENT CONFIDENT IN THAT...MAINLY DUE TO THE GFS SPITTING OUT A
LITTLE LIGHT QPF...BUT UNTIL THERE IS MORE MODELS TRENDING THAT WAY
WILL KEEP THE FORECAST AS IS. AT THE SFC...A COLD FRONT WILL HAVE
PUSHED ITS WAY THROUGH A MAJORITY OF THE CWA BY SUNRISE SUNDAY...BUT
WITH THE PARENT HIGH WELL NORTH OF THE AREA...NOT A BIG PUSH OF
STRONGER NORTH WINDS ACCOMPANYING THE FRONT. WILL BE A COLDER AIR
MASS BUILDING IN...AND FORECAST HIGHS CURRENTLY RANGE FROM NEAR 20
IN THE NORTH TO NEAR 30 IN THE SOUTH.
SUNDAY NIGHT AND MONDAY...A STRONGER SHORTWAVE TROUGH ASSOCIATED
WITH LOW PRESSURE NEAR THE HUDSON BAY AREA WILL PUSH SOUTH OUT OF
CENTRAL CANADA AND THROUGH NRN SECTIONS OF THE CONUS /AND EVENTUALLY
EAST/. THE PRIMARY PUSH LOOKS TO COME SUNDAY NIGHT...BRINGING A
REINFORCING SHOT OF NRLY WINDS AND COLDER AIR. WONT BE A BIG SHOT OF
WINDS...WITH SPEEDS JUST TOPPING OUT IN THE 10 TO 15 MPH RANGE. SFC
HIGH PRESSURE WILL STILL BE CENTERED OFF TO THE N/NE OF THE
CWA...BUT CLOSER THAN IT WAS SUNDAY...WITH THE ASSOCIATED RIDGE AXIS
EXTENDING SW THROUGH THE AREA. AT THIS POINT...MONDAY IS FORECAST TO
BE THE COLDEST DAY OF THE LONG TERM PERIOD...WITH HIGHS TOPPING OUT
IN THE MID TEENS NORTH TO NEAR 20 SOUTH. AS FAR AS PRECIPITATION
GOES...THAT SECOND PUSH OF THE FRONT WITH THIS DISTURBANCE LOOKS TO
KEEP THE BETTER CHANCES JUST OFF TO THE S/SE OF THE CWA...BUT WILL
BE SOMETHING FOR UPCOMING SHIFTS TO MONITOR AS IT WOULDNT TAKE A
SIGNIFICANT SHIFT BACK TO THE NW FOR OUR AREA TO POTENTIALLY BE
AFFECTED.
LOOKING TO THE TUES/TUES NIGHT TIME FRAME...MODELS ARE IN PRETTY
GOOD AGREEMENT SHOWING A PIECE OF UPPER LEVEL ENERGY DIGGING ITS WAY
SOUTH INTO THE ROCKIES MON/MON NIGHT...AND BY 12Z TUESDAY IS LOCATED
ROUGHLY OVER THE 4 CORNERS REGION. IT CONTINUES TO SHIFT EAST DURING
THE DAY...AND TUESDAY NIGHT MAY SWING CLOSE ENOUGH TO THE SRN
PORTIONS OF THE CWA TO BRING SOME SNOW CHANCES. THERE ARE STILL
PLENTY OF DIFFERENCES TO BE WORKED OUT WITH THE STRENGTH/TIMING/PATH
OF THIS SYSTEM...BUT KEPT POPS ON THE LOW SIDE...AS IN GENERAL THE
BRUNT OF IT SHOULD PASS THROUGH THE SRN PLAINS. NOT CONFIDENT IN HOW
IT WILL EVOLVE SO KEPT POPS CONFINED TO THAT 12HR PERIOD OF 00-12Z
WEDNESDAY. TUESDAY SHOULD SEE A REBOUND IN TEMPS COMPARED TO
MONDAY...AND HIGHS IN THE LOW/MID 20S ARE FORECAST.
WEDNESDAY THROUGH FRIDAY...THE WARMING TREND IN TEMPERATURES LOOKS
TO CONTINUE...WITH DRY CONDITIONS REMAINING IN THE FORECAST...AS
MORE NORTHWESTERLY FLOW DEVELOPS IN THE UPPER LEVELS THANKS TO AT
LEAST BRIEF RIDGING OVER THE WRN CONUS. MODELS ARE IN DECENT
AGREEMENT SHOWING MODERATING TEMPS ALOFT THROUGH THE FINAL 3 DAYS OF
THE PERIOD...WITH THE POTENTIAL OF DOWNSLOPING W/NW WINDS MAINLY
THURSDAY AND FRIDAY. BUMPED UP HIGHS A TOUCH FOR THOSE 2 DAYS FROM
SUPERBLEND GRIDS...WITH TEMPS RANGING FROM UPPER 20S/LOW 30S ON WED
TO LOWER/MID 40S FOR FRIDAY.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1138 PM CST FRI JAN 9 2015
CLOUDS WILL INCREASE DURING THE OVERNIGHT HOURS AND UPSTREAM CIGS
ARE AT VFR LEVELS. THE LLVL JET STRENGTHENS DURING THE OVERNIGHT
HOURS AND A PERIOD OF LLVL WIND SHEAR IS EXPECTED. MODELS ARE NOT
CONSISTENT ON WHETHER OR NOT THERE MAY BE VSBY RESTRICTIONS
SATURDAY EVENING IN BR AND HAVE NOT INCLUDED IN TAF ATTM.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...ADP
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
453 PM PST SUN JAN 11 2015
.SYNOPSIS...RAIN WILL DIMINISH BUT LOW CLOUDS WILL LINGER OVERNIGHT
ACROSS THE MOJAVE DESERT REGION AS A CIRCULATION MOVES FROM SOUTHERN
NEVADA INTO SOUTHERN ARIZONA. ONE FINAL WEATHER DISTURBANCE WILL
PUSH ACROSS THE SOUTHERN GREAT BASIN INTO UTAH AND ARIZONA MONDAY
BRINGING ADDITIONAL CHANCES FOR PRECIPITATION TO THOSE AREAS. DRY
AND PLEASANT WEATHER WILL RETURN TUESDAY THROUGH THE REST OF THE
WORK WEEK.
&&
.UPDATE...AN AREA OF FAIRLY WIDESPREAD LIGHT RAIN WAS MOVING NORTH
ACROSS SOUTHEAST SAN BERNARDINO COUNTY EARLY THIS EVENING WHICH THE
ECMWF DEPICTED NICELY IN THE 00Z-06Z QPF FIELD. I UPDATED TO RAISE
POPS THERE AND TO INCREASE QPF. -HARRISON-
&&
.PREV DISCUSSION...
320 PM PST SUN JAN 11 2015
.SHORT TERM...TONIGHT THROUGH MONDAY.
THE BROAD CLOUD/PRECIPITATION SHIELD THAT HAS BEEN OVER SOUTHERN
NEVADA AND THE WESTERN MOJAVE DESERT MUCH OF THE DAY WAS BEGINNING
TO SHOW SIGNS OF BREAKING UP SLIGHTLY. WE LIKELY SEE FAIRLY
EXTENSIVE PRECIPITATION BEGIN TO TAPER OFF OVER CENTRAL AND EASTERN
CLARK COUNTY LATE THIS AFTERNOON THROUGH EARLY THIS EVENING AS THE
UPPER LEVEL CIRCULATION OVER SOUTHERN CALIFORNIA BEGINS TO PICK UP A
LITTLE SPEED ON ITS WAY TOWARD SOUTHWEST ARIZONA. THE RAIN OVER THE
AREA FROM BARSTOW TO SOUTHERN SAN BERNARDINO SHOULD ALSO BEGIN TO
DIMINISH IN COVERAGE THROUGH EARLY EVENING. THE LATEST HRRR TRENDS
INDICATE ADDITIONAL RAINFALL AMOUNTS OF 0.10-0.20 CAN BE EXPECTED
BEFORE THE BROAD PRECIPITATION BAND FALLS APART. THE LATEST MODELS
INDICATE THAT THE LOW-MID LEVEL CLOUD COVER WILL BE SLOW TO CLEAR
OUT OVERNIGHT AND WE MAY NOT SEE MUCH CLEARING UNTIL AFTER SUNRISE
MONDAY. THE FOG LOW TEMP/DEWPOINT SPREADS WILL LIKELY RESULT IN
AREAS OF FOG WHERE SOAKING RAINS HAVE OCCURRED ACROSS SAN
BERNARDINO...CLARK AND MOHAVE COUNTIES THOUGH THE LACK OF
RADIATIONAL COOLING SHOULD NOT PRODUCE MUCH IN THE WAY OF DENSE FOG.
THE SHORT WAVE TROUGH CURRENTLY DROPPING INTO THE PACIFIC NORTHWEST
WILL LEAD TO A DRYER NORTHWEST FLOW OVER MUCH OF THE REGION MONDAY
WITH THE EXCEPTION OF EASTERN NEVADA. THIS WILL LEAD TO A CHANCE OF
PRECIPITATION OVER NORTHERN AND EASTERN LINCOLN COUNTY AND NORTHWEST
ARIZONA MONDAY AFTERNOON INTO MONDAY EVENING. WILL LEAVE A SLIGHT
CHANCE IN FOR THE SPRING MOUNTAINS ALSO DUE TO LINGERING MOISTURE
AND OROGRAPHIC EFFECTS. NORTH WINDS WILL INCREASE MONDAY EVENING AS
A COLD FRONT SWEEPS DOWN THROUGH THE MOJAVE DESERT.
.LONG TERM...TUESDAY THROUGH SUNDAY.
THE BACKSIDE OF LOW PRESSURE HANGS OVER THE AREA TUESDAY LEAVING A
SLIGHT CHANCE OF RAIN/HIGHER ELEVATION SNOW OVER PORTIONS OF THE
EASTERN CWA...PRIMARILY DURING THE EARLY MORNING HOURS. GUSTY NORTH
WINDS ARE EXPECTED AREA WIDE BEHIND A COLD FRONT THAT SWEEPS THROUGH
IN THE MORNING. STRONGER WINDS WILL BE CONFINED TO FAVORED AREAS
SUCH AS THE COLORADO RIVER VALLEY BUT WIND SPEEDS SHOULD REMAIN
BELOW ADVISORY LEVELS.
BRIEF RIDGING IS FORECAST WEDNESDAY BEFORE A WEAK UPPER DISTURBANCE
PASSES THROUGH THE NORTHERN GREAT BASIN AND FLATTENS THE RIDGE ON
THURSDAY. WESTERLY FLOW DOMINATES FRIDAY AND SATURDAY WITH
OCCASIONAL MID AND HIGH CLOUDS PASSING ACROSS THE AREA. THE GFS HAS
AN AGGRESSIVE SOLUTION FOR LATE IN THE WEEKEND AS IT BRINGS A STRONG
TROUGH INTO THE SOUTHWEST. IT HAS SUPPORT FROM ABOUT HALF OF THE GFS
ENSEMBLE MEMBERS WITH THE OTHER HALF MORE IN LINE WITH THE DRY ECMWF
AND GEM. CONTINUING TO HIGHLIGHT A DRY FORECAST THROUGH NEXT WEEKEND
UNTIL A CLEARER MODEL TREND IS ESTABLISHED.
NORTH WINDS LINGER IN THE COLORADO RIVER VALLEY THROUGH THURSDAY BUT
STRONGER WINDS BECOME MORE LOCALIZED BY THURSDAY. TEMPERATURES
THROUGH THE WEEK ARE EXPECTED TO BE NEAR TO SLIGHTLY ABOVE NORMAL
FOR THIS TIME OF YEAR.
&&
.AVIATION...FOR MCCARRAN...RAIN WILL TAPER OFF BY EARLY THIS EVENING
AS A STORM OVER SOUTHERN CALIFORNIA HEADS TOWARD SOUTHWEST ARIZONA.
HOWEVER...LOW CLOUDS WILL LINGER OVERNIGHT AND CIGS AROUND 5KFT MAY
PERSIST MUCH OF THE NIGHT BEFORE CLEARING OUT AFTER SUNRISE MONDAY.
WINDS WILL REMAIN LIGHT...GENERALLY UNDER 8 KTS THROUGH THE PERIOD.
THERE MAY BE SOME AREAS OF FOG AROUND THE LAS VEGAS VALLEY OVERNIGHT
BUT THE CHANCE OF DENSE FOG DEVELOPMENT AT THE TERMINAL IS VERY
REMOTE SINCE SKIES ARE NOT EXPECTED TO CLEAR.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A BROAD AREA OF RAIN WILL DISSIPATED THIS EVENING
ACROSS SOUTHEAST CALIFORNIA...FAR SOUTHERN NEVADA AND NORTHWEST
ARIZONA. CLOUD BASES OF TO 3K-6K FEET WILL LINGER OVERNIGHT
AND MOUNTAIN OBSCURATIONS WILL PERSIST. AREAS OF FOG WITH VSBY BELOW
3 STATUE MILES WILL BE POSSIBLE ACROSS THE MOJAVE DESERT REGION
OVERNIGHT. WINDS WILL REMAIN GENERALLY LIGHT THEN INCREASE FROM THE
NORTH OVER THE SOUTHERN GREAT BASIN MONDAY AFTERNOON AS A COLD FRONT
APPROACHES.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT REQUESTED
BUT SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS
THROUGH MONDAY ACCORDING TO STANDARD OPERATING PROCEDURES.
&&
$$
SHORT TERM/AVIATION...ADAIR
LONG TERM.............SALMEN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
320 PM PST SUN JAN 11 2015
.SYNOPSIS...RAIN WILL DIMINISH BUT LOW CLOUDS WILL LINGER OVERNIGHT
ACROSS THE MOJAVE DESERT REGION AS A CIRCULATION MOVES FROM SOUTHERN
NEVADA INTO SOUTHERN ARIZONA. ONE FINAL WEATHER DISTURBANCE WILL
PUSH ACROSS THE SOUTHERN GREAT BASIN INTO UTAH AND ARIZONA MONDAY
BRINGING ADDITIONAL CHANCES FOR PRECIPITATION TO THOSE AREAS. DRY
AND PLEASANT WEATHER WILL RETURN TUESDAY THROUGH THE REST OF THE
WORK WEEK.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY.
THE BROAD CLOUD/PRECIPITATION SHIELD THAT HAS BEEN OVER SOUTHERN
NEVADA AND THE WESTERN MOJAVE DESERT MUCH OF THE DAY WAS BEGINNING
TO SHOW SIGNS OF BREAKING UP SLIGHTLY. WE LIKELY SEE FAIRLY
EXTENSIVE PRECIPITATION BEGIN TO TAPER OFF OVER CENTRAL AND EASTERN
CLARK COUNTY LATE THIS AFTERNOON THROUGH EARLY THIS EVENING AS THE
UPPER LEVEL CIRCULATION OVER SOUTHERN CALIFORNIA BEGINS TO PICK UP A
LITTLE SPEED ON ITS WAY TOWARD SOUTHWEST ARIZONA. THE RAIN OVER THE
AREA FROM BARSTOW TO SOUTHERN SAN BERNARDINO SHOULD ALSO BEGIN TO
DIMINISH IN COVERAGE THROUGH EARLY EVENING. THE LATEST HRRR TRENDS
INDICATE ADDITIONAL RAINFALL AMOUNTS OF 0.10-0.20 CAN BE EXPECTED
BEFORE THE BROAD PRECIPITATION BAND FALLS APART. THE LATEST MODELS
INDICATE THAT THE LOW-MID LEVEL CLOUD COVER WILL BE SLOW TO CLEAR
OUT OVERNIGHT AND WE MAY NOT SEE MUCH CLEARING UNTIL AFTER SUNRISE
MONDAY. THE FOG LOW TEMP/DEWPOINT SPREADS WILL LIKELY RESULT IN
AREAS OF FOG WHERE SOAKING RAINS HAVE OCCURRED ACROSS SAN
BERNARDINO...CLARK AND MOHAVE COUNTIES THOUGH THE LACK OF
RADIATIONAL COOLING SHOULD NOT PRODUCE MUCH IN THE WAY OF DENSE FOG.
THE SHORT WAVE TROUGH CURRENTLY DROPPING INTO THE PACIFIC NORTHWEST
WILL LEAD TO A DRYER NORTHWEST FLOW OVER MUCH OF THE REGION MONDAY
WITH THE EXCEPTION OF EASTERN NEVADA. THIS WILL LEAD TO A CHANCE OF
PRECIPITATION OVER NORTHERN AND EASTERN LINCOLN COUNTY AND NORTHWEST
ARIZONA MONDAY AFTERNOON INTO MONDAY EVENING. WILL LEAVE A SLIGHT
CHANCE IN FOR THE SPRING MOUNTAINS ALSO DUE TO LINGERING MOISTURE
AND OROGRAPHIC EFFECTS. NORTH WINDS WILL INCREASE MONDAY EVENING AS
A COLD FRONT SWEEPS DOWN THROUGH THE MOJAVE DESERT.
.LONG TERM...TUESDAY THROUGH SUNDAY.
THE BACKSIDE OF LOW PRESSURE HANGS OVER THE AREA TUESDAY LEAVING A
SLIGHT CHANCE OF RAIN/HIGHER ELEVATION SNOW OVER PORTIONS OF THE
EASTERN CWA...PRIMARILY DURING THE EARLY MORNING HOURS. GUSTY NORTH
WINDS ARE EXPECTED AREA WIDE BEHIND A COLD FRONT THAT SWEEPS THROUGH
IN THE MORNING. STRONGER WINDS WILL BE CONFINED TO FAVORED AREAS
SUCH AS THE COLORADO RIVER VALLEY BUT WIND SPEEDS SHOULD REMAIN
BELOW ADVISORY LEVELS.
BRIEF RIDGING IS FORECAST WEDNESDAY BEFORE A WEAK UPPER DISTURBANCE
PASSES THROUGH THE NORTHERN GREAT BASIN AND FLATTENS THE RIDGE ON
THURSDAY. WESTERLY FLOW DOMINATES FRIDAY AND SATURDAY WITH
OCCASIONAL MID AND HIGH CLOUDS PASSING ACROSS THE AREA. THE GFS HAS
AN AGGRESSIVE SOLUTION FOR LATE IN THE WEEKEND AS IT BRINGS A STRONG
TROUGH INTO THE SOUTHWEST. IT HAS SUPPORT FROM ABOUT HALF OF THE GFS
ENSEMBLE MEMBERS WITH THE OTHER HALF MORE IN LINE WITH THE DRY ECMWF
AND GEM. CONTINUING TO HIGHLIGHT A DRY FORECAST THROUGH NEXT WEEKEND
UNTIL A CLEARER MODEL TREND IS ESTABLISHED.
NORTH WINDS LINGER IN THE COLORADO RIVER VALLEY THROUGH THURSDAY BUT
STRONGER WINDS BECOME MORE LOCALIZED BY THURSDAY. TEMPERATURES
THROUGH THE WEEK ARE EXPECTED TO BE NEAR TO SLIGHTLY ABOVE NORMAL
FOR THIS TIME OF YEAR.
&&
.AVIATION...FOR MCCARRAN...RAIN WILL TAPER OFF BY EARLY THIS EVENING
AS A STORM OVER SOUTHERN CALIFORNIA HEADS TOWARD SOUTHWEST ARIZONA.
HOWEVER...LOW CLOUDS WILL LINGER OVERNIGHT AND CIGS AROUND 5KFT MAY
PERSIST MUCH OF THE NIGHT BEFORE CLEARING OUT AFTER SUNRISE MONDAY.
WINDS WILL REMAIN LIGHT...GENERALLY UNDER 8 KTS THROUGH THE PERIOD.
THERE MAY BE SOME AREAS OF FOG AROUND THE LAS VEGAS VALLEY OVERNIGHT
BUT THE CHANCE OF DENSE FOG DEVELOPMENT AT THE TERMINAL IS VERY
REMOTE SINCE SKIES ARE NOT EXPECTED TO CLEAR.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A BROAD AREA OF RAIN WILL DISSIPATED THIS EVENING
ACROSS SOUTHEAST CALIFORNIA...FAR SOUTHERN NEVADA AND NORTHWEST
ARIZONA. CLOUD BASES OF TO 3K-6K FEET WILL LINGER OVERNIGHT
AND MOUNTAIN OBSCURATIONS WILL PERSIST. AREAS OF FOG WITH VSBY BELOW
3 STATUE MILES WILL BE POSSIBLE ACROSS THE MOJAVE DESERT REGION
OVERNIGHT. WINDS WILL REMAIN GENERALLY LIGHT THEN INCREASE FROM THE
NORTH OVER THE SOUTHERN GREAT BASIN MONDAY AFTERNOON AS A COLD FRONT
APPROACHES.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT REQUESTED
BUT SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS
THROUGH MONDAY ACCORDING TO STANDARD OPERATING PROCEDURES.
&&
$$
SHORT TERM/AVIATION...ADAIR
LONG TERM.............SALMEN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1238 AM EST SAT JAN 10 2015
.SYNOPSIS...
LAKE EFFECT SNOW SHOWERS WILL CONTINUE ACROSS CENTRAL NEW YORK AND
NORTHEAST PENNSYLVANIA INTO THE EVENING HOURS WITH JUST MINOR
ACCUMULATIONS EXPECTED. ANOTHER SYSTEM WILL APPROACH THE REGION
LATE SUNDAY NIGHT BRINGING LIGHT SNOW INTO THE AREA TO START OFF
THE NEW WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
6 PM UPDATE...
A BAND OF LAKE EFFECT SNOW OFF OF LAKE ERIE WILL BE OVER THE
CENTRAL SOUTHERN TIER AND PORTIONS OF THE SUSQUEHANNA REGION
THROUGH 5Z.
LATEST HRRR REFLECTIVITY PROG HAS A GOOD HANDLE ON BOTH THE ERIE
BAND AND THE ONTARIO BAND CURRENTLY OVER THE NORTH COUNTRY. BASED
ON RADAR TRENDS AND HRRR OUTPUT, WE PROJECT THE ERIE BAND TO DROP
ABOUT AN INCH OR TWO OF SNOW BETWEEN 23Z AND 5Z, BEFORE
DISSIPATING.
IT WILL BE A COLD NIGHT WITH MINIMUMS IN THE SINGLE DIGITS.
1 PM UPDATE...
SFC TROF IS WORKING ITS WAY THRU CWA THIS AFTN WITH A BAND OF SNOW
AND FURTHER FALLING TEMPS ACCOMPANYING IT. MOISTURE FM LK ERIE
SNOWBAND FM THIS MRNG HAS DISCONNECTED ITSELF FM LAKE AND IS CAUSING
MODERATE-HVY SNOW FOR AREAS NORTH OF THE SRN TIER. EXPECT LGT SNOW
SHOWERS TO CONTINUE FOR ALL ZONES FOR THE NEXT SVRL HRS UNTIL BNDRY
PUSHES THRU AND WINDS SETTLE BACK OUT FM THE SW.
FOR TONIGHT CWA WL BE ON FRINGES OF INTENSE LK EFFECT BANDS
STREAMING FM ONTARIO AND ERIE. FLOW LOOKS TO BE ALIGNED FM 260-265
DIRECTION AND THIS MAY BRING SOME SCTD SNOW SHOWERS TO ERN FINGER
LKS LOCALES BUT WL LKLY KEEP LK ONTARIO BAND NORTH OF NRN ONEIDA
CNTY. ANY LITTLE WAFFLING IN THE PLACEMENT OF THE BAND MAY DIP INTO
FAR NRN SXNS OF CNTY HWVR NOT EXPECTING ANYTHING MORE THAN AN INCH
OVRNGT FOR THE SRN TUG HILL PLATEAU.
QUESTION CNTRS ARND HOW FAR INLAND LK ERIE BAND CAN EXTEND. LATEST
HIRES MODELS SUGGEST IT WL PRESS AS FAR EAST AS THE WRN CATS AND
THUS INDICATE CHC POPS INTO OTSEGO CNTY ARND 05Z BFR BRINGING SNOWS
BACK FURTHER TO THE WEST AGAIN. AT MOST MAY SEE A FEW TENTHS OF AN
INCH OF SNOW ACCUMS TONIGHT MAINLY ALONG ROUTE 20 DUE TO LK ERIE
BAND.
WINDS WL RANGE FM 10-15KTS TONIGHT AS PRESSURE GRADIENT RMNS TIGHT.
TEMPS WL BE FALLING INTO THE SINGLE DIGITS TONIGHT. THESE TEMPS
COMBINED WITH STRONG WINDS WL PRODUCE ISOLD WIND CHILL VALUES APPCHG
-15F IN STEUBEN CNTY AND PORTIONS OF THE WRN CATS. HWVR NOT
EXPECTING THESE TO BE LONG ENUF OR WIDESPREAD ENUF TO JUSTIFY
ADVISORY AT THIS TIME.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
3 PM UPDATE...
HIPRES WL BE BUILDING INTO MID-ATLANTIC STATES ON SATURDAY PUSHING
LK BAND FURTHER AND FURTHER NORTH. SECONDARY COLD SURGE OVRNGT WL
HELP DROP TEMPS INTO THE SINGLE DIGITS TONIGHT AND ONLY ALLOW HIGHS
TOMORROW TO RISE INTO THE TEENS. SKIES CLEAR FM SOUTH TO NORTH UNDER
BUILDING SFC HIGH.
QUIET WX IS EXPECTED SAT NGT WITH HIPRES BUILDING OFF THE EAST
COAST. TEMPS WL SLOWLY DROP OFF TOMORROW NGT BFR BEGINNING TO RISE
ACRS THE WEST AFT 06Z. HV GONE WITH NON-DIURNAL TEMP TREND AS WSW H8
FLOW DRAWS IN WRMR H8 TEMPS DRG THE OVRNGT.
SUNDAY WL FEATURE INCREASING CLDS AS WARM ADVECTION INCREASES AHD OF
NEXT SFC BNDRY. CAN SEE LITTLE IN THE WAY OF FRCG MUCH BFR 06Z
MONDAY TO JUSTIFY CHC POPS WITH UPGLIDE INCREASING AFT THIS TIME.
WIDESPREAD LGT SNOW EXPECTED ON MONDAY AS BNDRY WORKS ITS WAY THRU
CWA DRG THE AFTN AND CLASHES WITH WV COMING UP FM THE SRN STREAM.
HOW MUCH OF A SNOW EVENT THIS MAY BE RMNS UP IN THE AIR WITH GFS
BEING FARTHEST OFFSHORE VS OTHER MODELS. NAM/CMC/EURO ALL SHOWING
SOME HINTS OF A COUPLE OF INCHES OF SNOW DRG THE DAY ON MONDAY.
MAXES ON MONDAY WL APPCH FRZG ACRS NEPA AND MAY RESULT IN MIXED PCPN
EVENT DRG THE AFTN HRS BUT STILL PLENTY OF TIME TO NARROW DOWN THE
DETAILS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
230 PM UPDATE...
FAIRLY QUIET PERIOD FORESEEN...WITH ARCTIC HIGH YIELDING COLD
TEMPERATURES EARLY ON...FOLLOWED BY TRENDING TOWARDS CLIMATOLOGY
WEDNESDAY-THURSDAY VIA SOUTHWEST FLOW.
STRONG SURFACE HIGH WILL HAVE DROPPED FROM THE CANADIAN HIGH
PLAINS TO THE UPPER MIDWEST BY MONDAY...AND THEN IT WILL BUILD
OVER OUR REGION MONDAY NIGHT THROUGH TUESDAY NIGHT. BRIEF LAKE
EFFECT SNOW SHOWERS OR FLURRIES WILL BE POSSIBLE DURING THE COLD
AIR ADVECTION MONDAY NIGHT...BUT WITH WINDS QUICKLY VEERING
NORTHERLY AND THUS DECREASING FETCH...ALONG AND SHALLOWNESS AND
DRYNESS OF THE BOUNDARY LAYER...IT WILL BE MINOR AT BEST. LOWS IN
SINGLE DIGITS TO LOW TEENS MONDAY NIGHT AND TUESDAY NIGHT...WITH
FEW SPOTS GETTING BELOW ZERO /ESPECIALLY NORTHERN REACHES OF
ONEIDA AND OTSEGO COUNTIES/. DURING TUESDAY ITSELF...A DRY ARCTIC DAY
WITH HIGHS MAINLY IN THE TEENS. A FLURRY OR TWO STILL POSSIBLE IN
THE FINGER LAKES REGION...IN ONE OF THOSE AIR MASSES WHERE ANY
CLOUD WILL BE PUTTING OUT A FEW DENDRITES /MOST OF WHICH WILL DRY
UP ON THE WAY TO THE GROUND/.
THE HIGH WEAKENS WEDNESDAY-THURSDAY...YET MAINTAINS AT LEAST A
RIDGE...KEEPING OUR WEATHER QUIET. PRIOR RUN OF ECMWF TRIED TO
BRING A COASTAL LOW CLOSE ENOUGH TO POTENTIALLY IMPACT SOME OF THE
REGION TOWARDS THURSDAY...BUT 12Z RUN NOW JOINS THE GFS AND
CANADIAN MODELS IN KEEPING IT WELL OUT TO SEA...WITH DRY RIDGE
STAYING IN CHARGE OF OUR WEATHER. AT THIS TIME WE ARE FIGURING ON
HIGHS IN THE 20S WEDNESDAY...AND NEAR CLIMATOLOGY NEXT THURSDAY.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDS CONT THRU THE PD. LE SNOW BANDS OFF ONTARIO AND ERIE
WILL REMAIN NORTH AND WEST OF THE TAF SITES AS THE FLOW CONTS AND
BECOMES EVEN MORE SWLY AHD OF AN APRCHG WV. GUSTY DAYTIME WINDS ON
SAT WILL BECOME LIGHTER AFT 00Z SUN AS WE STABILIZE.
OUTLOOK...
SUN...MAINLY VFR.
SUN NGT THRU MON NGT...RESTRICTIONS POSSIBLE IN -SN.
TUE-WED...MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVF
NEAR TERM...DJP/PVF
SHORT TERM...KAH/MLJ/PVF
LONG TERM...DGM/MDP
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
955 PM EST SUN JAN 11 2015
.SYNOPSIS...
A COASTAL FRONT WILL MOVE TOWARD THE COAST LATE TONIGHT WITH
SUBTROPICAL AIR SPREADING ONTO THE BEACHES. MUCH COLDER CONDITIONS
WILL PERSIST INLAND AS A WEDGE OF HIGH PRESSURE REMAINS ACROSS THE
INTERIOR CAROLINAS. A WEDGE OF HIGH PRESSURE WILL BUILD DOWN INTO
THE CAROLINAS MONDAY THROUGH WEDNESDAY...PUSHING THE BOUNDARY BACK
OFFSHORE AND CONTINUING UNSETTLED CONDITIONS. A LARGE AREA OF LOW
PRESSURE WILL MOVE WELL OFF THE SOUTHEAST COAST THURSDAY INTO FRIDAY
BEFORE HIGH PRESSURE RETURNS FOR THE WEEKEND WITH A WARMING TREND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 945 PM SUNDAY...THE COASTAL FRONT APPEARS TO HAVE MOVED VERY
LITTLE OVER THE PAST FEW HOURS. WE HAVE BEEN CLOSELY MONITORING
TEMPERATURE AND WIND DIRECTION TRENDS AT THE BALD HEAD ISLAND
MESONET SITE FOR ANY SIGN THE FRONT IS APPROACHING. THEIR CONDITIONS
ARE ALMOST UNCHANGED FROM THOSE BACK AT 630 PM. THIS TREND APPEARS
TO BE ECHOED BY THE NEW 00Z NAM WHICH HAS DELAYED THE COASTAL
FRONT`S ARRIVAL BY 3-4 HOURS...PLACING IT LATE TONIGHT FOR SE NORTH
CAROLINA AND CLOSE TO 12Z/7 AM EST FOR THE GRAND STRAND.
THE OTHER ITEM OF INTEREST IS SOME INTENSELY DRY AIR ACROSS THE
INLAND CAROLINAS. DEWPOINTS REMAIN IN THE 20S WITH SOME TEENS WEST
OF I-95 IN THE DARLINGTON-BENNETTSVILLE REGION. RADAR ECHOES ARE
BEGINNING TO INCREASE ACROSS CENTRAL SOUTH CAROLINA MEANING WE ARE
PROBABLY ONLY A COUPLE HOURS AWAY FROM SHOWERS DEVELOPING ACROSS THE
PEE DEE REGION. AIR TEMPERATURES REMAIN IN THE MID TO UPPER 40S...
AND WITH THESE LOW DEWPOINTS THE WET BULB TEMPERATURE IS AS LOW AS
35-36 DEGREES WEST OF I-95. WITH DEWPOINTS NOT ANTICIPATED TO FALL
ANY FURTHER I THINK WE CAN SAFELY RULE OUT ANY FREEZING RAIN
POTENTIAL AT LEAST IN OUR FORECAST AREA.
PREVIOUS DISCUSSION FROM 645 PM FOLLOWS...
THE COASTAL FRONT APPEARS TO BE LOCATED ABOUT 20 MILES EAST OF CAPE
FEAR BASED ON WIND DIRECTIONS AT BUOYS 41037 AND 41013
(SOUTHEASTERLY) VERSUS WIND DIRECTIONS AT THE BEACHES (NORTHERLY).
ALMOST ALL MODEL GUIDANCE SHOWS THE FRONT MOVING WESTWARD AND
ONSHORE AFTER MIDNIGHT...WITH TEMPERATURES RISING INTO THE UPPER 50S
TO LOWER 60S ACROSS THE CAPE FEAR REGION AND THE SC BEACHES LATE
TONIGHT. ON THE WEST SIDE OF THE COASTAL FRONT EVAPORATIONAL COOLING
IN RATHER DRY AIR SHOULD LOCK IN THE COLD TEMPERATURES WITH READINGS
IN THE UPPER 30S AND 40S EXPECTED. THE THERMAL BOUNDARY AT THE
SURFACE WILL BE INTENSE AND VERY DIFFICULT TO FORECAST ACCURATELY.
DESPITE THE CHALLENGING NATURE OF THIS FORECAST THERE WERE FEW
CHANGES NEEDED TO THE FORECAST. SHOWERS SHOULD STILL DEVELOP ACROSS
SOUTH CAROLINA AND INTERIOR NORTH CAROLINA LATE THIS EVENING...
FINALLY REACHING THE CAPE FEAR AREA LATE TONIGHT. FORECAST POPS
REMAIN AT 100 PERCENT AREA-WIDE. THE LATEST HRRR MODEL RUN
EXPLICITLY DEPICTS THE CONVECTIVE NATURE OF THE RAIN EVEN INLAND.
THIS MAKES SENSE AS SMALL ELEVATED INSTABILITY SHOULD DEVELOP DUE TO
WARM ADVECTION ON SOUTH WINDS JUST ABOVE THE SURFACE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...CHALLENGING FORECAST FOR MON AS A COASTAL
TROUGH ATTEMPTS TO PUSH ONSHORE AND A COOL WEDGE OF HIGH PRESSURE
BEGINS TO ERODE INLAND. AS IS COMMON WITH THESE SETUPS...SUBTLE
CHANGES TO THE POSITIONING/LOCATION OF THE COASTAL FRONT WILL HAVE
BIG IMPLICATIONS IN TERMS OF THE TEMP FORECAST FOR TOMORROW. IT DOES
APPEAR THE COASTAL FRONT WILL PUSH THROUGH AT LEAST OUR COASTAL
ZONES...BRINGING WARMER S-SW FLOW TO THESE LOCATIONS WHILE THE
INLAND ZONES REMAIN UNDER THE WANING INFLUENCE OF COOLER HIGH
PRESSURE. THE END RESULT IS A SHARP GRADIENT FOR HIGH TEMPS ON
MON...RANGING FROM LOW TO MID 60S AT THE BEACHES TO LOW TO MID 50S
WEST OF I-95.
HIGHER CONFIDENCE REGARDING THE PCPN FORECAST AS LKLY/CATEGORICAL
POPS WILL PREVAIL THROUGH THE MORNING/AFTN HOURS. MOIST ISENTROPIC
ASCENT COMBINED WITH AN UPPER DISTURBANCE LIFTING OUT OF THE GULF
WILL GENERATE STRATIFORM RAIN ACROSS THE REGION. MEANWHILE...SHOWERS
WILL DEVELOP IN THE WARMER AIR MASS BEHIND THE COASTAL FRONT. SPC
MENTIONS THE POSSIBILITY OF A FEW ISOLATED TSTMS ALONG THE COAST...
BUT WILL HOLD OFF ON MENTIONING THUNDER OVER OUR LAND ZONES ATTM.
EMBEDDED CONVECTIVE ELEMENTS COULD PRODUCE HEAVIER RAINFALL NEAR AND
BEHIND THE COASTAL TROUGH. AREA WIDE QPF FROM 7AM-7PM TOMORROW
FALLS IN THE 0.5-0.75 IN RANGE.
RAIN CHANCES DIMINISH INTO EARLY TUE AS LOW PRESSURE ALONG THE
TROUGH LIFTS UP THE ATLANTIC COAST. THEN COLD HIGH PRESSURE ONCE
AGAIN WEDGES DOWN THROUGH THE CAROLINAS...USHERING IN MUCH COOLER
AIR FOR TUE. HIGH TEMPS WILL BE IN THE MID/UPPER 40S INLAND TO LOWER
50S AT THE COAST. THESE HIGHS WILL BE REALIZED EARLY IN THE MORNING
AS TEMPS ARE EXPECTED TO FALL DURING THE DAY WITH CONTINUED COLD AIR
ADVECTION. MODEST OVERRUNNING MAY RESULT IN MORE -RA DURING THE
DAY...BUT POPS RAMP UP AGAIN OVERNIGHT AS ANOTHER SHORTWAVE FURTHER
ENHANCES LIFT OVER THE CAROLINAS. AFTER 09Z WED...A BRIEF WINDOW
EMERGES FOR -FZRA/FZDZ OVER OUR FAR NORTHWEST ZONES WEST OF I-95.
THE THREAT APPEARS MARGINAL AT THIS TIME SINCE THE COLD AIR WILL BE
CHASING THE MOISTURE...BUT THE POTENTIAL IS THERE IF SFC TEMPS DROP
BELOW FREEZING WITH ENOUGH MOISTURE STILL IN PLACE TO SUPPORT PCPN.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...COMPLEX AND ACTIVE PATTERN WILL MAINTAIN
PERIODS OF UNSETTLED WEATHER DURING THE LATTER HALF OF THE WEEK
BEFORE IMPROVEMENT DEVELOPS FOR THE UPCOMING WKND.
PERIOD BEGINS INTERESTING AS A WEAK SHORTWAVE WILL BE MOVING
OVERHEAD WEDNESDAY MORNING. AS THIS OCCURS...MID-LEVEL FLOW WILL
BACK INCREASINGLY TO THE SW...HELPING TO ERODE A COLD SURFACE WEDGE.
ALTHOUGH THE COLUMN WILL BE DRYING BY WEDNESDAY MORNING...RESIDUAL
LOW-LEVEL MOISTURE WILL MANIFEST AS OVERCAST LOW CLOUD COVER AND
PERIODS OF DRIZZLE ACROSS MUCH OF THE AREA. THE BIGGEST CONCERN IS
WHETHER LIGHT FREEZING RAIN/DRIZZLE WILL OCCUR FOR A FEW HOURS WELL
INLAND WEDNESDAY MORNING. FORECAST PROFILES SUGGEST A STRONG
INVERSION...COMMON IN A WEDGE SETUP...WITH SURFACE TEMPS IN THE NW
ZONES RIGHT AROUND 31/32 DEGREES. SURFACE WET BULB TEMPS ARE
FORECAST TO BE BELOW 32 ROUGHLY NW OF I-95...BUT THERE IS NO
SATURATION WITHIN THE DENDRITIC GROWTH ZONE (ALTHOUGH WITH A WARM
NOSE OF 6-8C THIS IS SORT OF IRRELEVANT IN THIS CASE).
THUS...-FZRA/FZDZ IS THE ONLY POSSIBLE P-TYPE OTHER THAN R-. LOCAL
TOP DOWN METHODOLOGY GIVES A SMALL STRIP OF R-/-FZRA FROM ABOUT TAR
HEEL...SW TO HARTSVILLE...AND WILL KEEP THIS IN OFFICIAL FORECAST
BUT WITH ONLY A FEW HUNDREDTHS OF AN INCH OF QPF...AT WORST.
WHILE QPF WILL BE MINIMAL...EVEN A BIT OF -FZRA/-FZDZ WOULD CAUSE
SOME IMPACTS WEDNESDAY MORNING SO THIS WILL NEED TO BE MONITORED
CLOSELY. FORTUNATELY...TEMPS BEFORE ANY FREEZING PRECIP WILL BE WARM
AND ACCOMPANIED BY RAIN...SO ROAD IMPACTS ARE EXPECTED TO BE MINIMAL
AT WORST. TEMPS WILL WARM TO ABOVE FREEZING BY LATE MORNING
EVERYWHERE...BUT DRIZZLE AND LOW CLOUDS WILL REMAIN THROUGH THE DAY
WILL TEMPS STRUGGLING ONLY INTO THE UPPER 30S/LOW 40S.
A MORE SIGNIFICANT STORM SYSTEM WILL THEN DEVELOP OFF THE SOUTHEAST
COAST THURSDAY NIGHT INTO FRIDAY. A CLOSED LOW ACROSS THE DESERT SW
WILL EJECT EAST ACROSS THE SOUTHERN TIER...WHILE A NORTHERN STREAM
SHORTWAVE WILL DIVE INTO THE MIDDLE OF THE COUNTRY. GUIDANCE SHOWS
DIFFERENT LEVELS OF PHASING NEAR THE GULF OF MEXICO WITH THESE
FEATURES...BUT EITHER WAY A LARGE LOW PRESSURE SYSTEM IS EXPECTED TO
MOVE UP THE COAST OVERNIGHT THURSDAY INTO FRIDAY. TEMPS ARE FORECAST
TO BE COLD...BUT ABOVE FREEZING...AND AS ISENTROPIC LIFT INCREASES
LATE THURSDAY INTO FRIDAY...A COLD RAIN IS EXPECTED AREA-WIDE. THE
RAIN COULD BE HEAVY...ESPECIALLY NEAR THE COAST...DEPENDING ON HOW
FAR OFFSHORE THE LOW TRACKS...AND CURRENT WPC QPF SHOWS UP TO
ONE-HALF INCH NEAR THE COAST.
AS THE LOW PULLS AWAY LATE FRIDAY...COOL HIGH PRESSURE WILL BUILD
EAST MAINTAINING BELOW NORMAL TEMPERATURES INTO THE WKND.
HOWEVER...THIS HIGH WILL PUSH OFF THE MID-ATLANTIC COAST SATURDAY AS
THE FLOW BECOMES MORE PROGRESSIVE...AND MOST OF THE WKND WILL
FEATURE ABUNDANT SUNSHINE WITH ABOVE NORMAL TEMPERATURES.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...THINGS WILL GO DOWN HILL RATHER RAPIDLY LATER THIS
EVENING AS ISENTROPIC LIFT COMMENCES. PRECIP WILL START OUT
SPORADICALLY AND LIGHT...BUT WILL QUICKLY BECOME STEAD AND
WIDESPREAD JUST AFTER MIDNIGHT. THE STEADY PRECIP WILL QUICKLY LOWER
CEILINGS TO MVFR...BECOMING IFR AN HOUR OR TWO LATER. VISIBILITIES
AS WELL WILL LIKELY LOWER TO IFR TOWARD MORNING. THE WEDGE WILL
LIKELY STAY IN AT THE INLAND TERMINALS FOR MOST OF THE DAY WITH
NORTHEAST WINDS...HOWEVER LOOK FOR THE WARM FRONT TO COME ONSHORE AT
THE COASTAL TERMINALS JUST AFTER DAYBREAK WITH A PRETTY SHARP WIND
SHIFT TO THE SOUTH. RAIN COULD BE HEAVY AT TIMES WITH AN EMBEDDED
SHOWER OR TWO.
EXTENDED OUTLOOK...RAIN AND MVFR/IFR CONDITIONS WILL PREVAIL MON
THROUGH TUE. MVFR/IFR CIGS MAY PERSIST INTO WED AS A COOL WEDGE
REMAINS LOCKED IN PLACE OVER THE CAROLINAS. RAIN/MVFR ON THU. VFR
FRI.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 945 PM SUNDAY...NO MOVEMENT HAS BEEN OBSERVED WITH THE COASTAL
FRONT OVER THE PAST FEW HOURS. RECENT MODEL TRENDS INDICATE THE
BOUNDARY SHOULD STILL MOVE ONSHORE...BUT DELAYED BY ABOUT 3-4 HOURS
FROM PREVIOUS THINKING. NE WINDS WILL VEER E-SE WITH THE PASSAGE OF
THE FRONT...ALSO ACCOMPANIED BY A SUDDEN INCREASE IN TEMPERATURES
AND HUMIDITY. SHOWER ACTIVITY HAS BEEN A LITTLE SLOWER TO DEVELOP
BUT RADAR TRENDS INDICATE SHOWERS ARE EXPANDING ACROSS CENTRAL SOUTH
CAROLINA. PREVIOUS DISCUSSION FROM 645 PM FOLLOWS...
THE COASTAL FRONT APPEARS TO BE LOCATED ABOUT 20 MILES EAST OF CAPE
FEAR...40 MILES EAST OF MYRTLE BEACH...AND 30 MILES EAST OF
GEORGETOWN. THIS IS BASED ON WIND DIRECTIONS AT BUOYS AND BEACH
LOCATIONS REPORTED WITHIN THE PAST HALF HOUR. VIRTUALLY ALL MODEL
GUIDANCE INDICATES THIS BOUNDARY SHOULD PUSH WESTWARD
TONIGHT...REACHING THE BEACHES A FEW HOURS AFTER MIDNIGHT WITH
SOUTHEASTERLY WINDS DEVELOPING. THIS WILL BRING IN A WARMER AND MUCH
MORE HUMID AIRMASS FROM THE GULF STREAM WITH AIR TEMPERATURES AND
DEWPOINTS RISING SIGNIFICANTLY FROM THEIR CURRENT LEVELS. SHOWERS
SHOULD INCREASE IN COVERAGE SOUTH OF CAPE FEAR LATE THIS
EVENING...SPREADING NORTH OF CAPE FEAR AFTER MIDNIGHT.
WITH SEA SURFACE TEMPERATURES IN THE 50S AND EVEN SOME UPPER 40S
ALONG THE SC COAST...SOME SEA FOG MAY DEVELOP AFTER MIDNIGHT AS
HUMID AIR FROM THE GULF STREAM ARRIVES.
SEAS CURRENTLY RANGE FROM 2-4 FEET AND SHOULD BUILD TOWARD 6 FEET
ACROSS OPEN WATERS LATE TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...SMALL CRAFT ADVISORY WILL BE IN EFFECT AT THE
START OF THE PERIOD. SEAS WILL BE RUNNING 5-7 FT WITH S-SW WINDS
20-25 KT IN RESPONSE TO A COASTAL TROUGH/FRONT OVER THE WATERS.
EXPECT SHOWERS/ISO TSTMS THROUGH THE DAY IN ASSOCIATION WITH THIS
FEATURE. THE WINDS WILL VEER AND RELAX A BIT AFTER 18Z...BECOMING
W-NW 10-15 KT...AS THE WAVE OF LOW PRESSURE LIFTS NORTHWARD. THIS
WILL HELP BRING AN END TO SCA CONDITIONS BY MONDAY EVENING AS SEAS
SUBSIDE TO 3-5 FT. COLD HIGH PRESSURE WEDGING DOWN ACROSS THE
CAROLINAS TUE WILL BE ACCOMPANIED BY A NORTHEASTERLY SURGE AS WIND
SPEEDS INCREASE TO 15-25 KT. SEAS WILL ACCORDINGLY BUILD TO 4-6 FT
AFTER 18Z TUE...5-7 FT OVER THE OUTER WATERS OF AMZ250/252...LIKELY
REQUIRING ANOTHER SCA TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...GUSTY NORTH WINDS ON THE PERIPHERY OF A WEDGE
OF HIGH PRESSURE WILL EASE THROUGH WEDNESDAY...FALLING FROM 20-25
KTS EARLY TO 10-15 KTS WEDNESDAY NIGHT. SEAS WILL DROP AS
WELL...FROM 4-7 FT FIRST THING WEDNESDAY...TO 2-4 FT BY THURSDAY
MORNING...AND A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED THE FIRST
HALF OF WEDNESDAY. ALTHOUGH THE WEDGE WILL BREAK DOWN THURSDAY...A
LARGE AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OFF THE SOUTHEAST
COAST AND RACE NORTHEAST INTO FRIDAY...MAINTAINING NORTHERLY WINDS.
THE PLACEMENT OF THIS LOW PRESSURE WILL HAVE SIGNIFICANT IMPACT ON
LOCAL WINDS...BUT EXPECT A STEADY INCREASE IN SPEEDS TO 20 KTS OR
MORE OVERNIGHT THURSDAY INTO FRIDAY BEFORE FALLING AGAIN LATE. SEAS
WILL BUILD ON THE STRONG WINDS BACK TO 3-5 FT...WITH UP TO 6 FT
POSSIBLE...AND ANOTHER SCA MAY BE NEEDED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 PM EST MONDAY
FOR AMZ250-252-254-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...BJR
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
650 PM EST SUN JAN 11 2015
.SYNOPSIS...
A COASTAL TROUGH WILL MOVE ONTO THE COAST LATE TONIGHT WITH
SUBTROPICAL AIR SPREADING ONTO THE BEACHES. MUCH COLDER CONDITIONS
WILL PERSIST INLAND AS A WEDGE OF HIGH PRESSURE REMAINS ACROSS THE
INTERIOR CAROLINAS. A WEDGE OF HIGH PRESSURE WILL BUILD DOWN INTO
THE CAROLINAS MONDAY THROUGH WEDNESDAY...PUSHING THE BOUNDARY BACK
OFFSHORE AND CONTINUING UNSETTLED CONDITIONS. A LARGE AREA OF LOW
PRESSURE WILL MOVE WELL OFF THE SOUTHEAST COAST THURSDAY INTO FRIDAY
BEFORE HIGH PRESSURE RETURNS FOR THE WEEKEND WITH A WARMING TREND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 645 PM SUNDAY...THE COASTAL FRONT APPEARS TO BE LOCATED ABOUT
20 MILES EAST OF CAPE FEAR BASED ON WIND DIRECTIONS AT BUOYS 41037
AND 41013 (SOUTHEASTERLY) VERSUS WIND DIRECTIONS AT THE BEACHES
(NORTHERLY). ALMOST ALL MODEL GUIDANCE SHOWS THE FRONT MOVING
WESTWARD AND ONSHORE AFTER MIDNIGHT...WITH TEMPERATURES RISING INTO
THE UPPER 50S TO LOWER 60S ACROSS THE CAPE FEAR REGION AND THE SC
BEACHES LATE TONIGHT. ON THE WEST SIDE OF THE COASTAL FRONT
EVAPORATIONAL COOLING IN RATHER DRY AIR SHOULD LOCK IN THE COLD
TEMPERATURES WITH READINGS IN THE UPPER 30S AND 40S EXPECTED. THE
THERMAL BOUNDARY AT THE SURFACE WILL BE INTENSE AND VERY DIFFICULT
TO FORECAST ACCURATELY.
DESPITE THE CHALLENGING NATURE OF THIS FORECAST THERE WERE FEW
CHANGES NEEDED TO THE FORECAST. SHOWERS SHOULD STILL DEVELOP ACROSS
SOUTH CAROLINA AND INTERIOR NORTH CAROLINA LATE THIS EVENING...
FINALLY REACHING THE CAPE FEAR AREA LATE TONIGHT. FORECAST POPS
REMAIN AT 100 PERCENT AREA-WIDE. THE LATEST HRRR MODEL RUN
EXPLICITLY DEPICTS THE CONVECTIVE NATURE OF THE RAIN EVEN INLAND.
THIS MAKES SENSE AS SMALL ELEVATED INSTABILITY SHOULD DEVELOP DUE TO
WARM ADVECTION ON SOUTH WINDS JUST ABOVE THE SURFACE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...CHALLENGING FORECAST FOR MON AS A COASTAL
TROUGH ATTEMPTS TO PUSH ONSHORE AND A COOL WEDGE OF HIGH PRESSURE
BEGINS TO ERODE INLAND. AS IS COMMON WITH THESE SETUPS...SUBTLE
CHANGES TO THE POSITIONING/LOCATION OF THE COASTAL FRONT WILL HAVE
BIG IMPLICATIONS IN TERMS OF THE TEMP FORECAST FOR TOMORROW. IT DOES
APPEAR THE COASTAL FRONT WILL PUSH THROUGH AT LEAST OUR COASTAL
ZONES...BRINGING WARMER S-SW FLOW TO THESE LOCATIONS WHILE THE
INLAND ZONES REMAIN UNDER THE WANING INFLUENCE OF COOLER HIGH
PRESSURE. THE END RESULT IS A SHARP GRADIENT FOR HIGH TEMPS ON
MON...RANGING FROM LOW TO MID 60S AT THE BEACHES TO LOW TO MID 50S
WEST OF I-95.
HIGHER CONFIDENCE REGARDING THE PCPN FORECAST AS LKLY/CATEGORICAL
POPS WILL PREVAIL THROUGH THE MORNING/AFTN HOURS. MOIST ISENTROPIC
ASCENT COMBINED WITH AN UPPER DISTURBANCE LIFTING OUT OF THE GULF
WILL GENERATE STRATIFORM RAIN ACROSS THE REGION. MEANWHILE...SHOWERS
WILL DEVELOP IN THE WARMER AIR MASS BEHIND THE COASTAL FRONT. SPC
MENTIONS THE POSSIBILITY OF A FEW ISOLATED TSTMS ALONG THE COAST...
BUT WILL HOLD OFF ON MENTIONING THUNDER OVER OUR LAND ZONES ATTM.
EMBEDDED CONVECTIVE ELEMENTS COULD PRODUCE HEAVIER RAINFALL NEAR AND
BEHIND THE COASTAL TROUGH. AREA WIDE QPF FROM 7AM-7PM TOMORROW
FALLS IN THE 0.5-0.75 IN RANGE.
RAIN CHANCES DIMINISH INTO EARLY TUE AS LOW PRESSURE ALONG THE
TROUGH LIFTS UP THE ATLANTIC COAST. THEN COLD HIGH PRESSURE ONCE
AGAIN WEDGES DOWN THROUGH THE CAROLINAS...USHERING IN MUCH COOLER
AIR FOR TUE. HIGH TEMPS WILL BE IN THE MID/UPPER 40S INLAND TO LOWER
50S AT THE COAST. THESE HIGHS WILL BE REALIZED EARLY IN THE MORNING
AS TEMPS ARE EXPECTED TO FALL DURING THE DAY WITH CONTINUED COLD AIR
ADVECTION. MODEST OVERRUNNING MAY RESULT IN MORE -RA DURING THE
DAY...BUT POPS RAMP UP AGAIN OVERNIGHT AS ANOTHER SHORTWAVE FURTHER
ENHANCES LIFT OVER THE CAROLINAS. AFTER 09Z WED...A BRIEF WINDOW
EMERGES FOR -FZRA/FZDZ OVER OUR FAR NORTHWEST ZONES WEST OF I-95.
THE THREAT APPEARS MARGINAL AT THIS TIME SINCE THE COLD AIR WILL BE
CHASING THE MOISTURE...BUT THE POTENTIAL IS THERE IF SFC TEMPS DROP
BELOW FREEZING WITH ENOUGH MOISTURE STILL IN PLACE TO SUPPORT PCPN.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...COMPLEX AND ACTIVE PATTERN WILL MAINTAIN
PERIODS OF UNSETTLED WEATHER DURING THE LATTER HALF OF THE WEEK
BEFORE IMPROVEMENT DEVELOPS FOR THE UPCOMING WKND.
PERIOD BEGINS INTERESTING AS A WEAK SHORTWAVE WILL BE MOVING
OVERHEAD WEDNESDAY MORNING. AS THIS OCCURS...MID-LEVEL FLOW WILL
BACK INCREASINGLY TO THE SW...HELPING TO ERODE A COLD SURFACE WEDGE.
ALTHOUGH THE COLUMN WILL BE DRYING BY WEDNESDAY MORNING...RESIDUAL
LOW-LEVEL MOISTURE WILL MANIFEST AS OVERCAST LOW CLOUD COVER AND
PERIODS OF DRIZZLE ACROSS MUCH OF THE AREA. THE BIGGEST CONCERN IS
WHETHER LIGHT FREEZING RAIN/DRIZZLE WILL OCCUR FOR A FEW HOURS WELL
INLAND WEDNESDAY MORNING. FORECAST PROFILES SUGGEST A STRONG
INVERSION...COMMON IN A WEDGE SETUP...WITH SURFACE TEMPS IN THE NW
ZONES RIGHT AROUND 31/32 DEGREES. SURFACE WET BULB TEMPS ARE
FORECAST TO BE BELOW 32 ROUGHLY NW OF I-95...BUT THERE IS NO
SATURATION WITHIN THE DENDRITIC GROWTH ZONE (ALTHOUGH WITH A WARM
NOSE OF 6-8C THIS IS SORT OF IRRELEVANT IN THIS CASE).
THUS...-FZRA/FZDZ IS THE ONLY POSSIBLE P-TYPE OTHER THAN R-. LOCAL
TOP DOWN METHODOLOGY GIVES A SMALL STRIP OF R-/-FZRA FROM ABOUT TAR
HEEL...SW TO HARTSVILLE...AND WILL KEEP THIS IN OFFICIAL FORECAST
BUT WITH ONLY A FEW HUNDREDTHS OF AN INCH OF QPF...AT WORST.
WHILE QPF WILL BE MINIMAL...EVEN A BIT OF -FZRA/-FZDZ WOULD CAUSE
SOME IMPACTS WEDNESDAY MORNING SO THIS WILL NEED TO BE MONITORED
CLOSELY. FORTUNATELY...TEMPS BEFORE ANY FREEZING PRECIP WILL BE WARM
AND ACCOMPANIED BY RAIN...SO ROAD IMPACTS ARE EXPECTED TO BE MINIMAL
AT WORST. TEMPS WILL WARM TO ABOVE FREEZING BY LATE MORNING
EVERYWHERE...BUT DRIZZLE AND LOW CLOUDS WILL REMAIN THROUGH THE DAY
WILL TEMPS STRUGGLING ONLY INTO THE UPPER 30S/LOW 40S.
A MORE SIGNIFICANT STORM SYSTEM WILL THEN DEVELOP OFF THE SOUTHEAST
COAST THURSDAY NIGHT INTO FRIDAY. A CLOSED LOW ACROSS THE DESERT SW
WILL EJECT EAST ACROSS THE SOUTHERN TIER...WHILE A NORTHERN STREAM
SHORTWAVE WILL DIVE INTO THE MIDDLE OF THE COUNTRY. GUIDANCE SHOWS
DIFFERENT LEVELS OF PHASING NEAR THE GULF OF MEXICO WITH THESE
FEATURES...BUT EITHER WAY A LARGE LOW PRESSURE SYSTEM IS EXPECTED TO
MOVE UP THE COAST OVERNIGHT THURSDAY INTO FRIDAY. TEMPS ARE FORECAST
TO BE COLD...BUT ABOVE FREEZING...AND AS ISENTROPIC LIFT INCREASES
LATE THURSDAY INTO FRIDAY...A COLD RAIN IS EXPECTED AREA-WIDE. THE
RAIN COULD BE HEAVY...ESPECIALLY NEAR THE COAST...DEPENDING ON HOW
FAR OFFSHORE THE LOW TRACKS...AND CURRENT WPC QPF SHOWS UP TO
ONE-HALF INCH NEAR THE COAST.
AS THE LOW PULLS AWAY LATE FRIDAY...COOL HIGH PRESSURE WILL BUILD
EAST MAINTAINING BELOW NORMAL TEMPERATURES INTO THE WKND.
HOWEVER...THIS HIGH WILL PUSH OFF THE MID-ATLANTIC COAST SATURDAY AS
THE FLOW BECOMES MORE PROGRESSIVE...AND MOST OF THE WKND WILL
FEATURE ABUNDANT SUNSHINE WITH ABOVE NORMAL TEMPERATURES.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...THINGS WILL GO DOWN HILL RATHER RAPIDLY LATER THIS
EVENING AS ISENTROPIC LIFT COMMENCES. PRECIP WILL START OUT
SPORADICALLY AND LIGHT...BUT WILL QUICKLY BECOME STEAD AND
WIDESPREAD JUST AFTER MIDNIGHT. THE STEADY PRECIP WILL QUICKLY LOWER
CEILINGS TO MVFR...BECOMING IFR AN HOUR OR TWO LATER. VISIBILITIES
AS WELL WILL LIKELY LOWER TO IFR TOWARD MORNING. THE WEDGE WILL
LIKELY STAY IN AT THE INLAND TERMINALS FOR MOST OF THE DAY WITH
NORTHEAST WINDS...HOWEVER LOOK FOR THE WARM FRONT TO COME ONSHORE AT
THE COASTAL TERMINALS JUST AFTER DAYBREAK WITH A PRETTY SHARP WIND
SHIFT TO THE SOUTH. RAIN COULD BE HEAVY AT TIMES WITH AN EMBEDDED
SHOWER OR TWO.
EXTENDED OUTLOOK...RAIN AND MVFR/IFR CONDITIONS WILL PREVAIL MON
THROUGH TUE. MVFR/IFR CIGS MAY PERSIST INTO WED AS A COOL WEDGE
REMAINS LOCKED IN PLACE OVER THE CAROLINAS. RAIN/MVFR ON THU. VFR
FRI.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 645 PM SUNDAY...THE COASTAL FRONT APPEARS TO BE LOCATED ABOUT
20 MILES EAST OF CAPE FEAR...40 MILES EAST OF MYRTLE BEACH...AND 30
MILES EAST OF GEORGETOWN. THIS IS BASED ON WIND DIRECTIONS AT BUOYS
AND BEACH LOCATIONS REPORTED WITHIN THE PAST HALF HOUR. VIRTUALLY
ALL MODEL GUIDANCE INDICATES THIS BOUNDARY SHOULD PUSH WESTWARD
TONIGHT...REACHING THE BEACHES A FEW HOURS AFTER MIDNIGHT WITH
SOUTHEASTERLY WINDS DEVELOPING. THIS WILL BRING IN A WARMER AND MUCH
MORE HUMID AIRMASS FROM THE GULF STREAM WITH AIR TEMPERATURES AND
DEWPOINTS RISING SIGNIFICANTLY FROM THEIR CURRENT LEVELS. SHOWERS
SHOULD INCREASE IN COVERAGE SOUTH OF CAPE FEAR LATE THIS
EVENING...SPREADING NORTH OF CAPE FEAR AFTER MIDNIGHT.
WITH SEA SURFACE TEMPERATURES IN THE 50S AND EVEN SOME UPPER 40S
ALONG THE SC COAST...SOME SEA FOG MAY DEVELOP AFTER MIDNIGHT AS
HUMID AIR FROM THE GULF STREAM ARRIVES.
SEAS CURRENTLY RANGE FROM 2-4 FEET AND SHOULD BUILD TOWARD 6 FEET
ACROSS OPEN WATERS LATE TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...SMALL CRAFT ADVISORY WILL BE IN EFFECT AT THE
START OF THE PERIOD. SEAS WILL BE RUNNING 5-7 FT WITH S-SW WINDS
20-25 KT IN RESPONSE TO A COASTAL TROUGH/FRONT OVER THE WATERS.
EXPECT SHOWERS/ISO TSTMS THROUGH THE DAY IN ASSOCIATION WITH THIS
FEATURE. THE WINDS WILL VEER AND RELAX A BIT AFTER 18Z...BECOMING
W-NW 10-15 KT...AS THE WAVE OF LOW PRESSURE LIFTS NORTHWARD. THIS
WILL HELP BRING AN END TO SCA CONDITIONS BY MONDAY EVENING AS SEAS
SUBSIDE TO 3-5 FT. COLD HIGH PRESSURE WEDGING DOWN ACROSS THE
CAROLINAS TUE WILL BE ACCOMPANIED BY A NORTHEASTERLY SURGE AS WIND
SPEEDS INCREASE TO 15-25 KT. SEAS WILL ACCORDINGLY BUILD TO 4-6 FT
AFTER 18Z TUE...5-7 FT OVER THE OUTER WATERS OF AMZ250/252...LIKELY
REQUIRING ANOTHER SCA TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...GUSTY NORTH WINDS ON THE PERIPHERY OF A WEDGE
OF HIGH PRESSURE WILL EASE THROUGH WEDNESDAY...FALLING FROM 20-25
KTS EARLY TO 10-15 KTS WEDNESDAY NIGHT. SEAS WILL DROP AS
WELL...FROM 4-7 FT FIRST THING WEDNESDAY...TO 2-4 FT BY THURSDAY
MORNING...AND A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED THE FIRST
HALF OF WEDNESDAY. ALTHOUGH THE WEDGE WILL BREAK DOWN THURSDAY...A
LARGE AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OFF THE SOUTHEAST
COAST AND RACE NORTHEAST INTO FRIDAY...MAINTAINING NORTHERLY WINDS.
THE PLACEMENT OF THIS LOW PRESSURE WILL HAVE SIGNIFICANT IMPACT ON
LOCAL WINDS...BUT EXPECT A STEADY INCREASE IN SPEEDS TO 20 KTS OR
MORE OVERNIGHT THURSDAY INTO FRIDAY BEFORE FALLING AGAIN LATE. SEAS
WILL BUILD ON THE STRONG WINDS BACK TO 3-5 FT...WITH UP TO 6 FT
POSSIBLE...AND ANOTHER SCA MAY BE NEEDED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 4 PM EST MONDAY
FOR AMZ250-252-254-256.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...BJR
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS BISMARCK ND
301 PM CST SAT JAN 10 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 301 PM CST SAT JAN 10 2015
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD IS SNOW CHANCES
WITH AN APPROACHING SHORTWAVE LATE TONIGHT THROUGH SUNDAY
MORNING...AND WIND CHILLS NORTH TONIGHT THROUGH MIDDAY SUNDAY.
A SHORTWAVE MOVING THROUGH MEAN WRN CANADA UPPER RIDGE CURRENTLY
MOVING FROM BRITISH COLUMBIA INTO ALBERTA...WILL COMBINE WITH A
NORTHERN STREAM SAVE DROPPING SOUTH FROM THE NORTHWEST TERRITORIES
AND MOVE INTO THE NORTHERN PLAINS LATE TONIGHT INTO SUNDAY. MID
LEVEL FORCING WILL PRODUCE A BAND OF LIGHT SNOW SPREADING FROM THE
LEE OF THE CANADIAN ROCKIES INTO EASTERN MONTANA THIS
EVENING...AND THEN ACROSS WESTERN NORTH DAKOTA AND INTO NORTHERN
SOUTH DAKOTA LATE TONIGHT THROUGH SUNDAY MORNING. THE TREND FROM
PREVIOUS RUNS HAS BEEN A LITTLE FARTHER NORTH WITH THE LIGHT
SNOW. HAVE UTILIZED BASICALLY A BLEND OF DETERMINISTIC GUIDANCE
WHICH BRINGS SLIGHT CHANCE TO CHANCE POPS MAINLY WEST AND SOUTH OF
LAKE SAKAKAWEA AND THE MISSOURI RIVER TONIGHT AND INTO THE FAR
SOUTH CENTRAL SUNDAY MORNING. THE LATEST MESOSCALE RAP AND HRRR
CONTINUE TO BRING THE BAND OF LIGHT SNOW EVEN A LITTLE FARTHER
NORTH...LIFTING NORTH AND EAST OF THE MISSOURI. WILL STICK WITH
THE CURRENT BLEND FOR NOW. SNOW AMOUNTS ARE EXPECTED TO BE LIGHT
WITH UNDER A HALF INCH...WITH POSSIBLY A HALF INCH TO AN INCH FROM
THE WEST CENTRAL INTO SOUTHWEST NORTH DAKOTA.
TO THE NORTH AND EAST...TEMPERATURES ARE IN THE SINGLE DIGITS
ABOVE ZERO ALONG THE CANADIAN BORDER...AND SHOULD DROP QUICKLY
THIS EVENING. WINDS WILL NOT BE STRONG BUT A STEADY 5 TO 10 MPH.
THIS WILL PRODUCE ADVISORY CRITERIA WINDS AGAIN LATE THIS EVENING
THROUGH SUNDAY MORNING ALONG THE CANADIAN BORDER. WILL ISSUE
ANOTHER ADVISORY TO COVER THIS.
SUNDAY WILL BRING TEMPERATURES SIMILAR TO TODAY WITH HIGHS FROM
NEAR ZERO NORTHEAST TO THE LOWER TEENS SOUTHWEST AND SOUTH
CENTRAL.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 301 PM CST SAT JAN 10 2015
COLD WITH DANGEROUS WIND CHILLS SUNDAY NIGHT...FOLLOWED BY A WARMING
TREND.
UPPER LEVEL NORTHWEST FLOW AND A LARGE SURFACE ARCTIC HIGH PRESSURE
SYSTEM WILL BE IN PLACE SUNDAY EVENING...WITH THE FORECAST CENTER OF
THE ARCTIC HIGH OVER SOUTHEASTERN SASKATCHEWAN/NORTHWESTERN
NORTH DAKOTA AROUND SUNSET SUNDAY EVENING. THE HIGH CENTER MOVES
SOUTHEAST ACROSS THE STATE SUNDAY NIGHT. BY DAYBREAK MONDAY MORNING
THE HIGH CENTER SHOULD BE OVER THE EASTERN DAKOTAS. NORTHWEST WINDS
SHOULD BE RATHER LIGHT - 5 TO 10 MPH SUNDAY EVENING AND UP TO 5 MPH
LATE SUNDAY NIGHT. LOW TEMPERATURES SHOULD BOTTOM OUT AROUND 15 TO
20 BELOW OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA. THE HIGH
CENTER SHOULD BE NORTH AND EAST OF THE SOUTHWESTERN PORTION OF THE
STATE...AND THERE THE OVERNIGHT LOWS SHOULD BE IN THE 10 TO 15 BELOW
ZERO RANGE. THESE MINIMUM TEMPERATURES COMBINED WITH THE WINDS UP TO
10 MPH AT TIMES WILL COMBINE TO PRODUCE WIND CHILLS IN THE 25 TO 30
BELOW ZERO RANGE (PERHAPS SOME ISOLATED LOCALES REACHING 35 BELOW
ZERO WIND CHILLS) FOR ALL BUT THE FAR SOUTHWESTERN COUNTIES OF NORTH
DAKOTA.
MONDAY AND MONDAY NIGHT: THE ARCTIC HIGH PRESSURE WILL CONTINUE
MOVING SOUTHEAST...AND THE UPPER LEVEL FLOW BEGINS CHANGING FROM
NORTHWEST TO A MORE ZONAL FLOW. LOOKING AT HIGHS MONDAY FROM JUST
ABOVE ZERO IN THE TURTLE MOUNTAINS AND JAMES RIVER VALLEY...TO THE
LOWER TEENS IN THE SOUTHWEST. LOWS WILL STILL BE BELOW ZERO MONDAY
NIGHT AS THE RESIDUAL ARCTIC AIR REMAINS OVER THE REGION.
THE CHANGING WEATHER PATTERN SHOULD BEGIN TO BE FELT ON TUESDAY AS
AN UPPER LEVEL RIDGE BEGINS BUILDING INTO THE WESTERN PLAINS...AND
AS SOUTHERLY SURFACE WINDS BEGIN TO BRING A MILDER PACIFIC AIRMASS
INTO THE REGION. LOOKING AT HIGHS TUESDAY IN THE TEENS AND LOWER 20S.
DRY CONDITIONS WILL CONTINUE AND TEMPERATURES WILL CONTINUE TO
MODERATE THROUGH THE WEEK AS PACIFIC RIDGING CONTINUES TO BUILD.
HIGHS ARE FORECAST TO BE AROUND AVERAGE (20S TO LOWER 30S) ON
WEDNESDAY...AND ABOVE AVERAGE (UPPER 20S TO MID/UPPER 30S) THURSDAY
THROUGH SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 301 PM CST SAT JAN 10 2015
VFR CEILINGS EXPECTED THROUGH THE TAF PERIOD...THOUGH CLOUDS WILL
INCREASE FROM WEST TO EAST ACROSS THE STATE. SMALL CHANCES FOR SNOW
IN/AROUND KDIK EARLY SUNDAY MORNING THROUGH NOON. WILL BRING IN
LOWER VFR CEILINGS AT KDIK AND HOLD OFF ON MVFR CEILINGS AT THIS
TIME.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 10 PM THIS EVENING TO NOON CST SUNDAY
FOR NDZ002>005-011>013.
&&
$$
SHORT TERM...TWH
LONG TERM...JV
AVIATION...AC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
852 PM EST SUN JAN 11 2015
.SYNOPSIS...
LOW PRESSURE SYSTEM AND MOSTLY RAIN TONIGHT. A COLD FRONT MOVES
THROUGH ON MONDAY. WEAK WAVE OF LOW PRESSURE SOUTH POSSIBLE MONDAY
NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
830 PM UPDATE. ALTHOUGH MOST TEMPERATURES REMAIN ABOVE
FREEZING...ENOUGH REPORTS OF LOCAL ICING WHERE GROUND IS STILL COLD
ENOUGH HAS PROMPTED AN EXPANSION OF THE FREEZING RAIN ADVISORY TO
COVER MOST OF THE AREA EXCEPT FOR SOUTHWEST VIRGINIA TIL 1 AM. THE
PREVIOUS FREEZING RAIN ADVISORIES REMAIN AS IS. TEMPERTUERS WILL
FINALLY BE RISING LATER TONIGHT.
PREVIOUS DISCUSSION...
630 PM UPDATE. PRECIP MOVED IN FASTER AND MADE ADJUSTMENTS IN POPS
ACCORDINGLY. ALSO INCLUDED SOME VERY LIGHT ICE PELLETS AND OR
FREEZING RAIN FOR MOST AREAS FOR 2-3 HOURS THIS EVENING...OUTSIDE OF
ADVISORY AREAS AND UP UNTIL FREEZING RAIN ADVISORIES BEGIN FOR THE
OTHER AREAS. ALL IN ALL...SOME SLIPPERY SPOTS POSSIBLE THIS EVENING
AND ADDRESSED IN SPECIAL WEATHER STATEMENT ISSUED EARLIER.
OTHERWISE...OUTSIDE OF ADVISORY AREAS PRECIP SHOULD BE ALL RAIN BY
03Z AS TEMPS BEGIN TO INCH UP AGAIN.
PREVIOUS DISCUSSION...
REMAIN CONCERNED WITH THE MODEL TRENDS OF GETTING WARMER FOR
TONIGHT IN SOUTHEAST OHIO AND EXTREME NORTHWESTERN WV. MET/MAV AND
LAV GUIDANCE ARE WARMER THAN THE FORECAST...BUT THE HRRR STILL SHOWS
WET BULBING CAUSING ISSUES. WITH SUCH LOW DEW POINTS
CURRENTLY...FROZEN GROUND...AND ADVISORIES ALREADY IN PLACE...WILL
HOLD TIGHT...BUT EVENING SHIFT WILL NEED TO MONITOR THIS CLOSELY.
HRRR AND NAM SOUNDINGS SHOWING POTENTIAL PROBLEMS IN THE SOUTHEAST
UPSLOPE AREAS OF THE NORTHERN MOUNTAINS AS WELL. IN THIS REGION
HOWEVER...LAV GUIDANCE IS SHOWING TEMPERATURE HOOVERING RIGHT AROUND
FREEZING AT LWB...WHICH IS NOT NORMALLY THE COLDEST SPOT. WITH
GROUND FROZEN...THINK THAT POCKETS OF FREEZING RAIN A GOOD BET. WILL
ISSUE A FREEZING RAIN ADVISORY OVERNIGHT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
WITH THE FRONTAL BOUNDARY OFF TO THE SOUTHEAST...WILL BE INFLUENCED
BY A DEVELOPING INVERTED SURFACE TROUGH SETTING UP ALONG THE
MOUNTAINS IN COMBINATION WITH A WEAK MID AND UPPER LEVEL WAVE. THE
RESULT IN THE GRIDS IS NOT TOO MUCH OF A CHANGE IN TERMS OF THE
POPS...KEEPING THE LOW END POPS OVER THE MOUNTAINS BEFORE ENDING
WEDNESDAY. LARGELY BASED THE POPS ON LOW-MID LEVEL LAYER
FRONTOGENESIS WHICH IS ON THE WEAKER SIDE...BUT STILL PRESENT WHEN
LOOKING AT THE NAM.
AN OVERRUNNING SITUATION WILL BE PRESENT WITH THE MOISTURE OVER THE
MOUNTAINS AS THE TROUGH SETS UP AND WILL KEEP IT SIMPLE IN THE
WEATHER GRIDS BY USING THE WARM LAYER ALOFT FROM THE NAM. THIS
CREATES BRIEF SLEET/FREEZING RAIN POTENTIAL BEFORE THE COLD AIR
ADVECTION TAKES HOLD AND TRANSITIONS THE WEATHER TYPE TO ALL SNOW
INTO TUESDAY. ALL THE WHILE...POPS WILL BE LOWERING.
NOT SEEING MUCH OF A TEMPERATURE RECOVERY TUESDAY FROM MONDAY NIGHT
GIVEN THE CLOUD COVER AND WEAK COLD AIR ADVECTION WHICH WILL BE HELD
IN CHECK BY THE MOISTURE PUSH FROM THE AFOREMENTIONED SURFACE TROUGH
FROM THE SOUTH. KEEPING IT COLD ENOUGH IN THE FORECAST FOR OFF AND
ON LIGHT SNOW OVER THE MOUNTAINS AFTER THE FULL PRECIPITATION TYPE
TRANSITION TUESDAY AND TUESDAY NIGHT...WITH SOME LOCATIONS CLIMBING
ABOVE FREEZING WEDNESDAY AS 850MB TEMPERATURES MODIFY SLIGHTLY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLDER AIR SWEEPS IN FOR A SEASONABLY COOL EXTENDED. EXPECTING A
MAINLY DRY EXTENDED IS IN THE CARDS.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
00Z MONDAY THRU 00Z TUESDAY...
LOW PRESSURE LIFTS UP ACROSS THE AREA TONIGHT AND MONDAY
MORNING...FOLLOWED BY A COLD FRONT LATER ON MONDAY. FOR
TONIGHT...THE PRECIPITATION WILL BE RAIN FOR MOST OF THE
REGION...BUT SOME SLEET OR FREEZING RAIN IS LIKELY IN THE
SOUTHEAST UPSLOPE AREAS OF POCAHONTAS COUNTY...PARTS OF SOUTHEAST
OHIO AND EXTREME NORTHWESTERN WV. AFTER 12Z...PRECIP WILL BE ALL
RAIN...POSSIBLY CHANGING TO WINTRY MIX OVER SOUTHEAST OHIO AND NWRN
WV AFTER 20Z BEHIND THE COLD FRONT.
LOOK FOR VFR CEILINGS IN SOME LIGHT MIXED PRECIP TO START THE
PERIOD...BECOMING MVFR CEILINGS AND VSBY 06Z TO 12Z...THEN IFR/LIFR
AFTER 12Z...IN WIDESPREAD PRECIP.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIO: TIMING OF LOWERING CEILINGS AND VISIBILITY
RESTRICTIONS COULD VARY.
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 MON 01/12/15
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EST 1HRLY 21 22 23 00 01 02 03 04 05 06 07 08
CRW CONSISTENCY H H H H H H M M M H H M
HTS CONSISTENCY H H H H H M H H H H H M
BKW CONSISTENCY H H H H H H H H H M M M
EKN CONSISTENCY H H H H H H H H H H M M
PKB CONSISTENCY H H H H H H H H L L L M
CKB CONSISTENCY H H H H H H H H L L L M
AFTER 00Z TUESDAY...
IFR POSSIBLE MONDAY NIGHT AND TUESDAY...ESPECIALLY MOUNTAINS
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY UNTIL 1 AM EST MONDAY FOR WVZ005>008-
013>020-024>032-034>040.
FREEZING RAIN ADVISORY UNTIL 6 AM EST MONDAY FOR WVZ009>011.
FREEZING RAIN ADVISORY UNTIL 9 AM EST MONDAY FOR WVZ046-047.
OH...FREEZING RAIN ADVISORY UNTIL 1 AM EST MONDAY FOR OHZ086-087.
FREEZING RAIN ADVISORY UNTIL 6 AM EST MONDAY FOR OHZ075-076-
083>085.
WINTER WEATHER ADVISORY UNTIL 9 AM EST MONDAY FOR OHZ066-067.
KY...FREEZING RAIN ADVISORY UNTIL 1 AM EST MONDAY FOR KYZ101>103-
105.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...RPY/JMV
SHORT TERM...26
LONG TERM...30
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
654 PM EST SUN JAN 11 2015
.SYNOPSIS...
LOW PRESSURE SYSTEM AND MOSTLY RAIN TONIGHT. A COLD FRONT MOVES
THROUGH ON MONDAY. WEAK WAVE OF LOW PRESSURE SOUTH POSSIBLE MONDAY
NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
630 PM UPDATE. PRECIP MOVED IN FASTER AND MADE ADJUSTMENTS IN POPS
ACCORDINGLY. ALSO INCLUDED SOME VERY LIGHT ICE PELLETS AND OR
FREEZING RAIN FOR MOST AREAS FOR 2-3 HOURS THIS EVENING...OUTSIDE OF
ADVISORY AREAS AND UP UNTIL FREEZING RAIN ADVISORIES BEGIN FOR THE
OTHER AREAS. ALL IN ALL...SOME SLIPPERY SPOTS POSSIBLE THIS EVENING
AND ADDRESSED IN SPECIAL WEATHER STATEMENT ISSUED EARLIER.
OTHERWISE...OUTSIDE OF ADVISORY AREAS PRECIP SHOULD BE ALL RAIN BY
03Z AS TEMPS BEGIN TO INCH UP AGAIN.
PREVIOUS DISCUSSION...
REMAIN CONCERNED WITH THE MODEL TRENDS OF GETTING WARMER FOR
TONIGHT IN SOUTHEAST OHIO AND EXTREME NORTHWESTERN WV. MET/MAV AND
LAV GUIDANCE ARE WARMER THAN THE FORECAST...BUT THE HRRR STILL SHOWS
WET BULBING CAUSING ISSUES. WITH SUCH LOW DEW POINTS
CURRENTLY...FROZEN GROUND...AND ADVISORIES ALREADY IN PLACE...WILL
HOLD TIGHT...BUT EVENING SHIFT WILL NEED TO MONITOR THIS CLOSELY.
HRRR AND NAM SOUNDINGS SHOWING POTENTIAL PROBLEMS IN THE SOUTHEAST
UPSLOPE AREAS OF THE NORTHERN MOUNTAINS AS WELL. IN THIS REGION
HOWEVER...LAV GUIDANCE IS SHOWING TEMPERATURE HOOVERING RIGHT AROUND
FREEZING AT LWB...WHICH IS NOT NORMALLY THE COLDEST SPOT. WITH
GROUND FROZEN...THINK THAT POCKETS OF FREEZING RAIN A GOOD BET. WILL
ISSUE A FREEZING RAIN ADVISORY OVERNIGHT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
WITH THE FRONTAL BOUNDARY OFF TO THE SOUTHEAST...WILL BE INFLUENCED
BY A DEVELOPING INVERTED SURFACE TROUGH SETTING UP ALONG THE
MOUNTAINS IN COMBINATION WITH A WEAK MID AND UPPER LEVEL WAVE. THE
RESULT IN THE GRIDS IS NOT TOO MUCH OF A CHANGE IN TERMS OF THE
POPS...KEEPING THE LOW END POPS OVER THE MOUNTAINS BEFORE ENDING
WEDNESDAY. LARGELY BASED THE POPS ON LOW-MID LEVEL LAYER
FRONTOGENESIS WHICH IS ON THE WEAKER SIDE...BUT STILL PRESENT WHEN
LOOKING AT THE NAM.
AN OVERRUNNING SITUATION WILL BE PRESENT WITH THE MOISTURE OVER THE
MOUNTAINS AS THE TROUGH SETS UP AND WILL KEEP IT SIMPLE IN THE
WEATHER GRIDS BY USING THE WARM LAYER ALOFT FROM THE NAM. THIS
CREATES BRIEF SLEET/FREEZING RAIN POTENTIAL BEFORE THE COLD AIR
ADVECTION TAKES HOLD AND TRANSITIONS THE WEATHER TYPE TO ALL SNOW
INTO TUESDAY. ALL THE WHILE...POPS WILL BE LOWERING.
NOT SEEING MUCH OF A TEMPERATURE RECOVERY TUESDAY FROM MONDAY NIGHT
GIVEN THE CLOUD COVER AND WEAK COLD AIR ADVECTION WHICH WILL BE HELD
IN CHECK BY THE MOISTURE PUSH FROM THE AFOREMENTIONED SURFACE TROUGH
FROM THE SOUTH. KEEPING IT COLD ENOUGH IN THE FORECAST FOR OFF AND
ON LIGHT SNOW OVER THE MOUNTAINS AFTER THE FULL PRECIPITATION TYPE
TRANSITION TUESDAY AND TUESDAY NIGHT...WITH SOME LOCATIONS CLIMBING
ABOVE FREEZING WEDNESDAY AS 850MB TEMPERATURES MODIFY SLIGHTLY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLDER AIR SWEEPS IN FOR A SEASONABLY COOL EXTENDED. EXPECTING A
MAINLY DRY EXTENDED IS IN THE CARDS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
00Z MONDAY THRU 00Z TUESDAY...
LOW PRESSURE LIFTS UP ACROSS THE AREA TONIGHT AND MONDAY
MORNING...FOLLOWED BY A COLD FRONT LATER ON MONDAY. FOR
TONIGHT...THE PRECIPITATION WILL BE RAIN FOR MOST OF THE
REGION...BUT SOME SLEET OR FREEZING RAIN IS LIKELY IN THE
SOUTHEAST UPSLOPE AREAS OF POCAHONTAS COUNTY...PARTS OF SOUTHEAST
OHIO AND EXTREME NORTHWESTERN WV. AFTER 12Z...PRECIP WILL BE ALL
RAIN...POSSIBLY CHANGING TO WINTRY MIX OVER SOUTHEAST OHIO AND NWRN
WV AFTER 20Z BEHIND THE COLD FRONT.
LOOK FOR VFR CEILINGS IN SOME LIGHT MIXED PRECIP TO START THE
PERIOD...BECOMING MVFR CEILINGS AND VSBY 06Z TO 12Z...THEN IFR/LIFR
AFTER 12Z...IN WIDESPREAD PRECIP.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIO: TIMING OF LOWERING CEILINGS AND VISIBILITY
RESTRICTIONS COULD VARY.
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 MON
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06
CRW CONSISTENCY H H H H H M M H H H H H
HTS CONSISTENCY H H H H H M M H H H H H
BKW CONSISTENCY H H H H H M M M H H H L
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H M M M H M M M L
CKB CONSISTENCY H H H H H H M M H H H L
AFTER 00Z TUESDAY...
IFR POSSIBLE MONDAY NIGHT AND TUESDAY...ESPECIALLY MOUNTAINS
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY FROM 10 PM THIS EVENING TO 9 AM EST
MONDAY FOR WVZ046-047.
FREEZING RAIN ADVISORY UNTIL 6 AM EST MONDAY FOR WVZ009>011.
OH...WINTER WEATHER ADVISORY UNTIL 9 AM EST MONDAY FOR OHZ066-067.
FREEZING RAIN ADVISORY UNTIL 6 AM EST MONDAY FOR OHZ075-076-
083>085.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...RPY/JMV
SHORT TERM...26
LONG TERM...30
AVIATION...JMV
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
935 PM CST SUN JAN 11 2015
.UPDATE...
MORE WIDESPREAD AREAS OF FOG AND DRIZZLE HAVE DEVELOPED ACROSS THE
REGION AHEAD OF A COLD FRONT CURRENTLY MOVING SOUTH THROUGH
OKLAHOMA. EXPECT THE FOG AND DRIZZLE TO PERSIST TONIGHT ACROSS
ROUGHLY THE EASTERN 2/3RDS OF THE AREA WHERE OVERCAST SKIES WILL
PERSIST AS WELL. CLOUD COVER IS A CHALLENGE TONIGHT BUT NOT
NECESSARILY A HINDRANCE TO THE FORECAST. MOST OF THE MODELS HAVE
THE CURRENT LOW CLOUD COVER STARTING TO ERODE FROM WEST TO EAST
BEGINNING IN THE LAST HOUR...BUT THE WESTERN EDGE OF THE CLOUDS IS
NOT ERODING AND IS EVEN BUILDING WEST SOME. THE HRRR IS THE ONLY
MODEL INDICATING THIS TREND AND IT KEEPS CLOUDY SKIES THROUGH THE
NIGHT. WILL ADJUST THE SKIES TO INDICATE CLOUDY/OVERCAST SKIES
THROUGH THE NIGHT WITH SOME CLEARING IN OUR SOUTHWEST COUNTIES
LATE TONIGHT.
THE COLD FRONT WILL BEGIN MOVING INTO THE REGION LATE TONIGHT WITH
THE COLDER AND DRIER AIR ARRIVING ON MONDAY. THEREFORE...ADJUSTED
DEWPOINTS UP SEVERAL DEGREES OVERNIGHT WITH THE DRYING TREND
BEING DELAYED UNTIL TOMORROW. DUE TO THE HIGHER
DEWPOINTS...INCREASED CLOUD COVER...AND THE SLOWER ARRIVAL OF
COLD AIR ADVECTION...ALSO ADJUSTED OVERNIGHT LOW TEMPS UP TO
VALUES VERY NEAR CURRENT TEMPERATURE READINGS. OVERNIGHT LOWS WILL
TEND TO REMAIN NEARLY STEADY THROUGH THE NIGHT. WITH COLD AIR
ADVECTION COMMENCING TOMORROW...SEVERAL LOCATIONS IN OUR NORTHWEST
WILL BARELY SEE ANY TEMPERATURE CHANGE TONIGHT AND TOMORROW.
WE DO NOT ANTICIPATE WIDESPREAD DENSE FOG TO OCCUR TONIGHT...BUT
THERE COULD BE SEVERAL AREAS THAT FALL BELOW 1 MILE THROUGHOUT THE
NIGHT WITH SOME POSSIBLY FALLING AROUND 1/4 MILE AT TIMES. WILL
NOT ISSUE A DENSE FOG ADVISORY AT THIS TIME.
82/JLD
&&
.AVIATION...
/ISSUED 611 PM CST SUN JAN 11 2015/
CONCERNS...IFR TO LIFR CONDITIONS EXPECTED THROUGH MID MORNING
MONDAY. WIND SHIFT WITH A COLD FRONT AROUND 09Z MONDAY IN THE
METROPLEX... 11Z AT WACO.
SATELLITE IMAGERY SHOWS THAT BACK EDGE OF THE LOW CLOUDS EXTENDED
FROM JUST EAST OF KSPS /WICHITA FALLS/ TO JUST WEST OF KMKN
/COMANCHE/ AT 2330Z. THIS IS ABOUT AS FAR EAST AS THE CLEARING
LINE WILL MOVE AS IT WILL MOVE BACK TO THE WEST THIS EVENING. IFR
CONDITIONS PREVAIL AT THE METROPLEX TAF SITES WITH SOME LOCATIONS
REPORTING SOME 3-6SM BR AT TAF ISSUANCE TIME. EXPECT THE CEILINGS
TO LOWER INTO THE LIFR CATEGORY BY 04Z...AND THE FOG WILL REDUCE
VISIBILITIES TO 1 MILE OR LESS OVERNIGHT. A COLD FRONT THAT IS
CURRENTLY EXTENDS FROM SOUTHEASTERN NEBRASKA SOUTHWEST INTO THE
SOUTHEASTERN COLORADO WILL MOVE SOUTHEAST TONIGHT... APPROACHING
THE METROPLEX AROUND 09Z AND INTO WACO AROUND 11Z.
CEILINGS/VISIBILITIES SHOULD IMPROVE A LITTLE WITH FRONTAL
PASSAGE. NORTH WINDS WILL INCREASE TO 15 TO 20 KNOTS BY 15Z AND
CEILINGS SHOULD IMPROVE INTO THE LOWER END OF THE MVFR CATEGORY.
58
&&
.PREV DISCUSSION... /ISSUED 302 PM CST SUN JAN 11 2015/
THE SHORTWAVE TROUGH THAT BROUGHT RAIN TO MOST OF THE AREA LAST
NIGHT WAS LOCATED OVER SOUTHWEST MISSOURI EARLY THIS AFTERNOON PER
WATER VAPOR SATELLITE IMAGERY. EARLY AFTERNOON VISIBLE SATELLITE
IMAGERY SHOWED A DECK OF LOW STRATUS CLOUDS OVER MOST OF THE
CWA...WITH A SHARP CUT-OFF TO CLEAR SKIES APPROXIMATELY ALONG A
WICHITA FALLS TO POSSUM KINGDOM LAKE LINE. THIS CLEARING LINE WAS
MAKING SLOW PROGRESS TO THE EAST...BUT THIS CLEARING WILL LIKELY
ONLY MAKE IT TO MINERAL WELLS BEFORE SUNSET. AS A RESULT...MOST OF
NORTH AND CENTRAL TEXAS WILL SEE TEMPERATURES HOLD STEADY IN THE
UPPER 30S TO LOW 40S THROUGH THIS EVENING.
FOR TONIGHT THROUGH WEDNESDAY...WATER VAPOR SATELLITE IMAGERY
OBSERVED SHORTWAVE TROUGHS ALONG THE CO/WY BORDER...AND JUST OFF
SHORE THE SOUTHERN CALIFORNIA COAST. A STRONGER UPPER TROUGH WAS
LOCATED OFF THE OREGON COAST...EXTENDING NORTHWEST OVER THE FAR
NORTHEAST PACIFIC OCEAN. THESE FEATURES ARE EXPECTED TO HAVE SOME
IMPACT ON OUR LOCAL AREA FORECAST THROUGH WEDNESDAY
THE CO/WY TROUGH IS EXPECTED TO MOVE EAST OVER THE CENTRAL PLAINS
TONIGHT SENDING A COLD FRONT SOUTH ACROSS THE SOUTH PLAINS. THIS
COLD FRONT IS EXPECTED TO MOVE ACROSS THE CWA BEFORE SUNRISE
TOMORROW MORNING. DUE TO THE UPPER LEVEL LIFT/SUPPORT REMAINING SO
FAR NORTH OF TEXAS...DO NOT EXPECT MUCH IN THE WAY OF RAIN CHANCES
ALONG THIS FRONT. LOW-LEVEL MOISTURE ALREADY IN PLACE WILL BE
LIFTED BY THE FRONT AS IT MOVES THROUGH...SO THINK THAT THERE WILL
BE A CHANCE FOR SPRINKLES OR DRIZZLE JUST ABOUT ANYWHERE ACROSS
NORTH AND CENTRAL TEXAS TOMORROW MORNING ALONG AND BEHIND THE
FRONT. HAVE A MIXTURE OF SPRINKLES AND PATCHY FOG IN THE FORECAST
TO ACCOUNT FOR THIS LOW-LEVEL MOISTURE LIFTING OVER THE FRONT
TOMORROW MORNING.
CHANCES FOR LIGHT RAIN DIMINISH BY LATE MORNING AS STRONGER NORTH
WINDS SEND SOME SLIGHTLY DRIER AIR INTO THE REGION. NORTH WINDS
ARE EXPECTED TO PICK UP TO 15 TO 20 MPH BY NOON TOMORROW. WIND
GUSTS ARE EXPECTED TO BE AS HIGH AS 25 TO 30 MPH AT TIMES.
TEMPERATURES ARE EXPECTED TO REMAIN COOL BEHIND THE FRONT...BUT
THE AIRMASS MOVING IN BEHIND THE FRONT DOES NOT LOOK ARCTIC IN
NATURE...SO A DRAMATIC COOL DOWN IS NOT EXPECTED AT THIS TIME.
THE SOUTHERN CALIFORNIA TROUGH IS EXPECTED TO MOVE OVER NORTH
TEXAS MONDAY NIGHT. AT THIS TIME MODEL GUIDANCE INDICATES THAT
THERE WILL NOT BE ENOUGH MOISTURE IN PLACE FOR ANY SIGNIFICANT
RAIN CHANCES ASSOCIATED WITH THIS SECONDARY TROUGH TOMORROW NIGHT.
HOWEVER WE WILL HAVE TO ASSESS THE LOW-LEVEL MOISTURE PROFILES
MONDAY EVENING TO SEE HOW MUCH DRY AIR HAS ADVECTED INTO THE
REGION AFTER BREEZY NORTH WINDS MONDAY AFTERNOON. AS LONG AS LOW-
LEVELS ARE NOT SATURATED...RAIN CHANCES SHOULD REMAIN NEAR ZERO
MONDAY NIGHT AS THIS TROUGH MOVES OVERHEAD. IF WE ARE
SATURATED...DRIZZLE WOULD BE MORE LIKELY. DRIZZLE IS USUALLY NOT
A BIG DEAL...HOWEVER TEMPERATURES ARE EXPECTED TO FALL BELOW
FREEZING BY TUESDAY MORNING FOR A LARGE PORTION OF THE CWA.
FREEZING DRIZZLE COULD BE AN ISSUE IF WE DO NOT DRY OUT ENOUGH
MONDAY AFTERNOON. AT THIS TIME THINK THAT WE WILL REMAIN DRY
ENOUGH TO AVOID FREEZING DRIZZLE CONCERNS MONDAY NIGHT/TUESDAY
MORNING.
THE OREGON UPPER TROUGH IS EXPECTED TO MOVE OVER THE SOUTHERN
PLAINS FROM TUESDAY NIGHT INTO WEDNESDAY. AT THIS TIME GUIDANCE HAS
CONTINUED ITS TREND ADVERTISING A WEAKER...STRONGLY POSITIVELY
TILTED...TROUGH MOVING OVER THE AREA. WITH LIMITED MOISTURE TO
WORK WITH...THE ADVERTISED WEAK LIFT ASSOCIATED WITH THIS TROUGH
LOOKS UNLIKELY TO PRODUCE ANY SIGNIFICANT PRECIPITATION ACROSS
NORTH AND CENTRAL TEXAS. HOWEVER...THIS TROUGH LOOKS STRONG RIGHT
NOW ON WATER VAPOR SATELLITE IMAGERY...SO WE WILL HAVE TO MONITOR
THIS TROUGH OVER THE NEXT 48 HOURS AND MAKE SURE IT DOES WEAKEN AS
IT APPROACHES. ANY PRECIPITATION ALONG THE RED RIVER ON TUESDAY
NIGHT INTO WEDNESDAY MORNING LOOKS LIKE IT WOULD BE SNOW...OR A
RAIN/SNOW MIX. NO ACCUMULATIONS ARE EXPECTED AS THIS
TIME...HOWEVER STRONGER LIFT COULD EASILY RESULT IN SOME MINOR
ACCUMULATIONS OF SNOW ACROSS THE NORTHERN COUNTIES OF THE CWA.
HAVE A 20 PERCENT CHANCE OF LIGHT RAIN ACROSS THE ENTIRE CWA ON
WEDNESDAY AS THE TROUGH MOVES EAST OVER THE AREA.
BEHIND THE MID-WEEK TROUGH...MOST MODEL GUIDANCE INDICATES THAT
WEAK RIDGING...OR POSSIBLY JUST ZONAL FLOW...TAKES SHAPE OVER THE
SOUTHERN PLAINS FOR LATE THIS WEEK INTO THE WEEKEND. AS A
RESULT...HAVE A DRY FORECAST IN PLACE WITH TEMPERATURES WARMING
EACH DAY DUE TO THE EXPECTATION FOR A RETURN TO PERSISTENT
SOUTHERLY WINDS BY LATE THIS WEEK. MODEL GUIDANCE DOES HINT AT THE
POTENTIAL FOR A LARGE UPPER TROUGH TO AFFECT THE REGION EITHER
LATE SUNDAY OR INTO EARLY NEXT WEEK. DID NOT PLACE ANY MENTION OF
POPS IN THE FORECAST AT THIS TIME FOR THIS SYSTEM AS MOST GUIDANCE
DELAYS ITS PASSAGE OVER THE REGION UNTIL EARLY NEXT WEEK.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 39 42 30 38 31 / 10 10 10 10 10
WACO, TX 41 44 32 42 32 / 10 10 10 10 20
PARIS, TX 36 41 31 38 29 / 10 10 10 10 10
DENTON, TX 39 42 28 37 28 / 10 10 10 10 20
MCKINNEY, TX 39 42 29 38 29 / 10 10 10 10 10
DALLAS, TX 40 42 31 39 32 / 10 10 10 10 10
TERRELL, TX 41 44 32 39 31 / 10 10 10 10 10
CORSICANA, TX 42 44 33 42 32 / 10 10 10 10 10
TEMPLE, TX 42 47 33 43 32 / 10 10 10 10 20
MINERAL WELLS, TX 39 41 28 38 28 / 10 10 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/82
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
209 PM CST SAT JAN 10 2015
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 209 PM CST SAT JAN 10 2015
NORTHWEST FLOW ALOFT CONTINUES ACROSS THE REGION PER LATEST WATER
VAPOR/500 MB RAP ANALYSIS. A WEAK MID-LEVEL WAVE/SURFACE TROUGH
WITHIN THIS FLOW WAS DROPPING INTO THE DAKOTAS/MN THIS AFTERNOON
WITH DECENT WING OF 285-290K ISENTROPIC LIFT/WAA OUT AHEAD OF IT
INTO OUR AREA. THIS HAS RESULTED IN WIDESPREAD EXPANSION OF
ALTOCUMULUS/STRATOCUMULUS THROUGH THE DAY. NO SNOW FLURRY ACTIVITY
YET PER SURFACE OBSERVATIONS...BUT RADAR PICKING UP ON VIRGA AROUND
3KFT...SO EXPECTING AT LEAST A FEW FLURRIES GOING THROUGH THE REST
OF THIS AFTERNOON. OTHERWISE...TEMPERATURES ACROSS THE AREA THIS
AFTERNOON WERE IN THE SINGLE DIGITS/TEENS ABOVE ZERO.
LOOK FOR THE MID-LEVEL WAVE/SURFACE TROUGH TO CONTINUE SLIPPING
SOUTHEAST INTO THE REGION THIS EVENING...AND THEN EAST OF THE AREA
AROUND MIDNIGHT. WILL KEEP MENTION OF FLURRIES IN THROUGH THE
EVENING HOURS...MAINLY NORTHEAST OF I-94 BUT THEN DROPPED THEM AFTER
MIDNIGHT WITH FORCING EXITING THE AREA. OTHERWISE...LOOKS LIKE
SUBSTANTIAL MID-LEVEL CLOUD COVER WILL LINGER THROUGH THE OVERNIGHT
HOURS. AS A RESULT...TEMPERATURES ONLY EXPECTED TO DROP INTO THE
SINGLE DIGITS BELOW TO NEAR 10 ABOVE.
FOR SUNDAY AFTERNOON/EVENING...LOOKING AT ANOTHER WEAK MID-LEVEL
TROUGH DROPPING ACROSS THE REGION. NAM INDICATING DECENT AMOUNT OF
850-500MB FRONTOGENESIS WITH THE TROUGH AS IT DROPS SOUTHEAST ACROSS
THE AREA. BASED ON THIS SIGNAL...ADDED MENTION OF FLURRIES AS NAM
BUFKIT SOUNDINGS SHOWING ALMOST TOTAL COLUMN SATURATION. PLAN ON
HIGHS MOSTLY IN THE TEENS...WITH A FEW LOWER 20S ACROSS NORTHEAST IA
INTO FAR SOUTHWEST WI. NORTHWEST WINDS AND A PUSH OF ARCTIC AIR
OVERSPREAD THE AREA OVERNIGHT WITH LOWS DIPPING DOWN INTO THE SINGLE
DIGITS ABOVE AND BELOW ZERO. COMBINED WITH NORTHWEST WINDS AROUND 10
MPH...LOOKING FOR WIND CHILL VALUES IN THE TEENS TO NEAR 20 BELOW
ACROSS PARTS OF SOUTHEAST MN INTO NORTH CENTRAL WI.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 209 PM CST SAT JAN 10 2015
COLD START TO THE NEW WORK WEEK AS MODIFIED ARCTIC AIRMASS MOVES
ACROSS THE REGION. PLAN ON HIGHS MONDAY AND TUESDAY IN THE SINGLE
DIGITS/TEENS ABOVE ZERO WITH LOWS MONDAY NIGHT IN THE SINGLE DIGITS
ABOVE AND BELOW ZERO.
LOOKING AT A SLOW WARMING TREND THEN FOR WEDNESDAY THROUGH SATURDAY
AS FLOW ACROSS THE CONUS BECOMES MORE HIGH ZONAL. THIS WILL TAP MORE
PACIFIC ORIGIN AIR INTO THE REGION WITH ARCTIC AIR RETREATING BACK
NORTH OF THE CANADIAN BORDER. MODEL CONSENSUS PRODUCES HIGH
TEMPERATURES WEDNESDAY IN THE TEENS TO LOWER 20S...THEN MODERATING
INTO THE UPPER 20S TO LOWER 30S BY FRIDAY AND SATURDAY. INCREASE IN
MID-LEVEL HEIGHTS/RIDGING KEEPS ANY WEATHER WELL NORTH OF THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1104 AM CST SAT JAN 10 2015
VFR CEILINGS HAVE DEVELOPED OVER THE AREA AS MOISTURE RETURNS FROM
THE SOUTHWEST AHEAD OF WEAK COLD FRONT/SURFACE TROUGH APPROACHING
FROM THE WEST. BASED ON THE 10.12Z NAM...LOOKS LIKE VFR CEILINGS
IN THE 5 TO 6K FEET RANGE WILL STICK AROUND INTO THE EARLY EVENING
BEFORE MOVING EAST OF THE AREA. MID LEVEL CLOUDS WILL STILL BE
OVER THE AREA FOR A HIGHER VFR CEILING FOR MUCH OF THE NIGHT. THE
WEAK COLD FRONT/SURFACE TROUGH SHOULD COME THROUGH OVERNIGHT
SWINGING THE WINDS AROUND TO THE NORTH/NORTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM....DAS
LONG TERM.....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1141 AM MST SAT JAN 10 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 340 AM MST SAT JAN 10 2015
COMPARED TO RECENT MORNINGS...TODAY WILL SEE A BENIGN START.
WINDS HAVE BEEN BREEZY OVERNIGHT ACROSS THE WIND CORRIDOR...WITH
GUSTS PEAKING AT AROUND 40-45 MPH. THESE WINDS COMBINED WITH A
THICK MID-LEVEL CLOUD CANOPY HAS NOT DONE THE ANTICIPATED FOG
DEVELOPMENT ANY FAVORS. HRRR SUPPORTS THIS IDEA...SO HAVE REMOVED
IT FROM THE MORNING FORECAST. OTHERWISE...HAVE SEEN THE
DEVELOPMENT OF A LEE WAVE CLOUD SINCE LAST EVENING AS MID- LEVEL
MOISTURE HAS STREAMED IN FROM THE PACNW. GOES PROVING GROUND
SYNTHETIC IMAGERY DID AN EXCELLENT JOB IN CAPTURING THIS FTR AND
SHOWS IT STICKING AROUND THRU A LARGE CHUNK OF TODAY. LLVL
GRADIENTS WILL SLOWLY DECREASE TODAY AS WELL WHICH WILL CUT GUSTS
IN THE WIND CORRIDOR DOWN TO AROUND 25-30 MPH BY SUNSET.
TEMPERATURES WILL BE NOTICEABLY WARMER TODAY AS H7 TEMPERATURES
HOVER BETWEEN 0 AND -2C. THIS WILL RESULT IN HIGHS CLIMBING AT
LEAST INTO THE 30S...WITH EVEN SOME LOW/MID 40S IN THE SOUTHEAST
WYOMING PLAINS AND SRN NEBRASKA PANHANDLE. NW FLOW WILL BACK TO
MORE ZONAL TODAY PRODUCING A FAVORABLE OROGRAPHIC COMPONENT INTO
THE WEST SLOPES OF THE SIERRA MADRE RANGES. DID ADD SOME SNOW
CHANCES AS A RESULT...THOUGH ANY ACCUMULATIONS WOULD BE VERY
LIGHT. BY TONIGHT MODELS ARE CONSISTENT IN TRACKING WK SHORTWAVE
ENERGY EAST THRU THE CWFA TONIGHT. WILL CONTINUE WITH SNOW
CHANCES OVR THE MOUNTAINS TONIGHT AND HAVE EVEN SPREAD THEM
FARTHER DOWN THE WEST SLOPE...FROM BAGGS TO CRESTON JCT.
NEXT COLD FRONT DROPS SOUTH ON SUNDAY. HIGH TEMPERATURES WILL
DEPEND UPON TIMING OF THE FRONT. ALTHOUGH MODELS THINK THAT HIGHS
WILL BE REACHED LATE MORNING OR MIDDAY FOR AREAS NORTH OF HIGHWAY
26. WILL SEE SOME LIGHT SNOW ASSOCIATED WITH THE FRONT AND LLVL
UPSLOPE IN ITS WAKE DEVELOP BY SUNDAY AFTERNOON. THE NAM EVEN
SUGGESTS ATMOSPHERIC STABILITY WILL WEAKEN ENOUGH FOR NW-SE
ORIENTED SNOW BAND DEVELOPMENT DURING THE AFTERNOON HOURS. FOR
NOW...EXPECT THIS ACTIVITY TO BE LIGHT...BUT MAY SEE BRIEF HEAVIER
SNOW RATES SHOULD THESE BANDS MATERIALIZE. LLVL WIND FLOW TURNS
FROM THE NORTHEAST SUNDAY TO SOUTHEAST SUNDAY NT. THIS WILL SET
UP A FAVORABLE FOG SET-UP MAINLY FOR AREAS ALONG THE EXTREME
SOUTHEAST PLAINS. HAVE ADDED FOG MENTION LATE SUNDAY NT AND EARLY
MONDAY MORNING. THERE MAY EVEN BE SOME FZDZ MIXED IN FOR EARLY
MONDAY MORNING...BUT IT LOOKS LESS FAVORABLE THAN THE LAST EVENT.
SNOW CHANCES WILL LESSEN AND BE CONFINED WEST OF I25 ON MONDAY AS
SOUTHEAST LLVL WINDS WEAKEN OROGRAPHIC INFLUENCE. TEMPS WILL BE
THE COOLEST ON MONDAY IN THE POST FRONTAL AIR MASS...BUT NOT ALL
THAT COLD WITH 30S TO NR 40F FOR HIGHS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 340 AM MST SAT JAN 10 2015
RELATIVELY QUIET IN THE LONG RANGE WITH THE ONLY FORECAST CONCERN
BEING THE UPPER LEVEL TROUGH PUSHING SOUTH OF THE REGION ON
TUESDAY. ALL MODELS SHOW THIS PACIFIC TROUGH MOVING SOUTHEAST
RAPIDLY...WELL SOUTH OF THE FORECAST AREA...SO EXPECT LIMITED
IMPACTS OVER SOUTHEAST WYOMING AND WESTERN NEBRASKA. THE GFS AND
ECMWF GENERALLY SHOW LIGHT PRECIP ALONG AND SOUTH OF I80 TUESDAY
AND TUESDAY NIGHT AS THE TROUGH SLIDES EAST OF THE
SOUTHERN/CENTRAL ROCKY MOUNTAINS. THE GEM IS MUCH FURTHER NORTH
AND A BIT MORE AGGRESSIVE...SHOWING ACCUMULATING SNOWFALL ACROSS
THE AREA. KEPT POP BETWEEN 4O TO 60 PERCENT ACROSS THE MOUNTAINS
AND GENERALLY 15 TO 20 PERCENT OVER THE LOWER ELEVATIONS FROM
RAWLINS...TO LARAMIE AND CHEYENNE EAST OF THE LARAMIE RANGE. KEPT
POP BELOW 10 PERCENT ACROSS WESTERN NEBRASKA. IN EITHER
CASE...TEMPERATURES WILL BE BELOW NORMAL AND IN THE 20S AND LOW
30S FOR HIGHS.
DRY NORTHWEST FLOW IS EXPECTED BY THE PACIFIC TROUGH THURSDAY WITH
SLOWLY MODIFYING TEMPERATURES. HIGHS BACK INTO THE UPPER 30S TO
MID 40S ARE EXPECTED BY THURSDAY. TEMPERATURES NEAR 50 ARE
POSSIBLE BY LATE NEXT WEEK AS THE UPPER LEVEL PATTERN BECOMES MORE
ZONAL. NO MAJOR WIND CONCERNS ARE ANTICIPATED THROUGH THE MIDDLE
OF NEXT WEEK WITH WINDS POSSIBLY INCREASING INTO FRIDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1133 AM MST SAT JAN 10 2015
WYOMING AERODROMES...VFR PREVAILS...WITH PERIODIC MVFR AT
RAWLINS IN SNOW SHOWERS ALONG WITH MOUNTAIN OBSCUREMENT THROUGH
01Z. FROM 10Z TO 15Z AT RAWLINS...IFR IN LOW CLOUDS AND FOG
PREVAIL...WITH VFR AT LARAMIE AND CHEYENNE. SNOWY...SIERRA MADRE
AND NORTHERN LARAMIE RANGES MOSTLY OBSCURED. AFTER 15Z...VFR
PREVAILS AT ALL WYOMING TAF SITES.
NEBRASKA AERODROMES...VFR PREVAILS THROUGH 06Z. FROM 06Z TO 15Z...
OCCASIONAL IFR AND MVFR IN FOG AND LOW CLOUDS. AFTER 15Z...
VFR AND OCCASIONAL MVFR PREVAIL.
&&
.FIRE WEATHER...
ISSUED AT 340 AM MST SAT JAN 10 2015
COOL TEMPERATURES...SOMEWHAT UNSETTLED CONDITIONS AND SNOW COVERED
FUELS WILL KEEP ANY FIRE WEATHER CONCERNS AT BAY THROUGH THE
WEEKEND AND UPCOMING WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CAH
LONG TERM...TJT
AVIATION...RUBIN
FIRE WEATHER...CAH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
341 AM MST SAT JAN 10 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 340 AM MST SAT JAN 10 2015
COMPARED TO RECENT MORNINGS...TODAY WILL SEE A BENIGN START.
WINDS HAVE BEEN BREEZY OVERNIGHT ACROSS THE WIND CORRIDOR...WITH
GUSTS PEAKING AT AROUND 40-45 MPH. THESE WINDS COMBINED WITH A
THICK MID-LEVEL CLOUD CANOPY HAS NOT DONE THE ANTICIPATED FOG
DEVELOPMENT ANY FAVORS. HRRR SUPPORTS THIS IDEA...SO HAVE REMOVED
IT FROM THE MORNING FORECAST. OTHERWISE...HAVE SEEN THE
DEVELOPMENT OF A LEE WAVE CLOUD SINCE LAST EVENING AS MID- LEVEL
MOISTURE HAS STREAMED IN FROM THE PACNW. GOES PROVING GROUND
SYNTHETIC IMAGERY DID AN EXCELLENT JOB IN CAPTURING THIS FTR AND
SHOWS IT STICKING AROUND THRU A LARGE CHUNK OF TODAY. LLVL
GRADIENTS WILL SLOWLY DECREASE TODAY AS WELL WHICH WILL CUT GUSTS
IN THE WIND CORRIDOR DOWN TO AROUND 25-30 MPH BY SUNSET.
TEMPERATURES WILL BE NOTICEABLY WARMER TODAY AS H7 TEMPERATURES
HOVER BETWEEN 0 AND -2C. THIS WILL RESULT IN HIGHS CLIMBING AT
LEAST INTO THE 30S...WITH EVEN SOME LOW/MID 40S IN THE SOUTHEAST
WYOMING PLAINS AND SRN NEBRASKA PANHANDLE. NW FLOW WILL BACK TO
MORE ZONAL TODAY PRODUCING A FAVORABLE OROGRAPHIC COMPONENT INTO
THE WEST SLOPES OF THE SIERRA MADRE RANGES. DID ADD SOME SNOW
CHANCES AS A RESULT...THOUGH ANY ACCUMULATIONS WOULD BE VERY
LIGHT. BY TONIGHT MODELS ARE CONSISTENT IN TRACKING WK SHORTWAVE
ENERGY EAST THRU THE CWFA TONIGHT. WILL CONTINUE WITH SNOW
CHANCES OVR THE MOUNTAINS TONIGHT AND HAVE EVEN SPREAD THEM
FARTHER DOWN THE WEST SLOPE...FROM BAGGS TO CRESTON JCT.
NEXT COLD FRONT DROPS SOUTH ON SUNDAY. HIGH TEMPERATURES WILL
DEPEND UPON TIMING OF THE FRONT. ALTHOUGH MODELS THINK THAT HIGHS
WILL BE REACHED LATE MORNING OR MIDDAY FOR AREAS NORTH OF HIGHWAY
26. WILL SEE SOME LIGHT SNOW ASSOCIATED WITH THE FRONT AND LLVL
UPSLOPE IN ITS WAKE DEVELOP BY SUNDAY AFTERNOON. THE NAM EVEN
SUGGESTS ATMOSPHERIC STABILITY WILL WEAKEN ENOUGH FOR NW-SE
ORIENTED SNOW BAND DEVELOPMENT DURING THE AFTERNOON HOURS. FOR
NOW...EXPECT THIS ACTIVITY TO BE LIGHT...BUT MAY SEE BRIEF HEAVIER
SNOW RATES SHOULD THESE BANDS MATERIALIZE. LLVL WIND FLOW TURNS
FROM THE NORTHEAST SUNDAY TO SOUTHEAST SUNDAY NT. THIS WILL SET
UP A FAVORABLE FOG SET-UP MAINLY FOR AREAS ALONG THE EXTREME
SOUTHEAST PLAINS. HAVE ADDED FOG MENTION LATE SUNDAY NT AND EARLY
MONDAY MORNING. THERE MAY EVEN BE SOME FZDZ MIXED IN FOR EARLY
MONDAY MORNING...BUT IT LOOKS LESS FAVORABLE THAN THE LAST EVENT.
SNOW CHANCES WILL LESSEN AND BE CONFINED WEST OF I25 ON MONDAY AS
SOUTHEAST LLVL WINDS WEAKEN OROGRAPHIC INFLUENCE. TEMPS WILL BE
THE COOLEST ON MONDAY IN THE POST FRONTAL AIR MASS...BUT NOT ALL
THAT COLD WITH 30S TO NR 40F FOR HIGHS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY NIGHT)
ISSUED AT 340 AM MST SAT JAN 10 2015
RELATIVELY QUIET IN THE LONG RANGE WITH THE ONLY FORECAST CONCERN
BEING THE UPPER LEVEL TROUGH PUSHING SOUTH OF THE REGION ON
TUESDAY. ALL MODELS SHOW THIS PACIFIC TROUGH MOVING SOUTHEAST
RAPIDLY...WELL SOUTH OF THE FORECAST AREA...SO EXPECT LIMITED
IMPACTS OVER SOUTHEAST WYOMING AND WESTERN NEBRASKA. THE GFS AND
ECMWF GENERALLY SHOW LIGHT PRECIP ALONG AND SOUTH OF I80 TUESDAY
AND TUESDAY NIGHT AS THE TROUGH SLIDES EAST OF THE
SOUTHERN/CENTRAL ROCKY MOUNTAINS. THE GEM IS MUCH FURTHER NORTH
AND A BIT MORE AGGRESSIVE...SHOWING ACCUMULATING SNOWFALL ACROSS
THE AREA. KEPT POP BETWEEN 4O TO 60 PERCENT ACROSS THE MOUNTAINS
AND GENERALLY 15 TO 20 PERCENT OVER THE LOWER ELEVATIONS FROM
RAWLINS...TO LARAMIE AND CHEYENNE EAST OF THE LARAMIE RANGE. KEPT
POP BELOW 10 PERCENT ACROSS WESTERN NEBRASKA. IN EITHER
CASE...TEMPERATURES WILL BE BELOW NORMAL AND IN THE 20S AND LOW
30S FOR HIGHS.
DRY NORTHWEST FLOW IS EXPECTED BY THE PACIFIC TROUGH THURSDAY WITH
SLOWLY MODIFYING TEMPERATURES. HIGHS BACK INTO THE UPPER 30S TO
MID 40S ARE EXPECTED BY THURSDAY. TEMPERATURES NEAR 50 ARE
POSSIBLE BY LATE NEXT WEEK AS THE UPPER LEVEL PATTERN BECOMES MORE
ZONAL. NO MAJOR WIND CONCERNS ARE ANTICIPATED THROUGH THE MIDDLE
OF NEXT WEEK WITH WINDS POSSIBLY INCREASING INTO FRIDAY MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH SUNDAY MORNING)
ISSUED AT 347 AM MST SAT JAN 10 2015
GENERALLY VFR CONDITIONS ACROSS MOST TERMINALS TODAY. CURRENTLY
MONITORING THE POTENTIAL FOR FOG ACROSS SOUTHEAST WYOMING...BUT
NOT MUCH HAS DEVELOPED EARLY THIS MORNING. EAST OF KCYS...VIS DOWN
TO 5 MILES AT TIMES NEAR PINE BLUFFS. BUT WITH A WESTERLY WIND AT
KCYS...DO NOT EXPECT FOG TO FORM AT THIS TIME. FOR WESTERN
NEBRASKA...THERE IS A CHANCE OF FOG FOR KSNY THIS MORNING BUT
CONFIDENCE IS PRETTY LOW AT THIS TIME. BREEZY CONDITIONS ARE
EXPECTED TODAY OVER SOUTHEAST WYOMING...ESPECIALLY FROM AROUND
INTERSTATE 25 AND AREAS TO THE WEST.
&&
.FIRE WEATHER...
ISSUED AT 340 AM MST SAT JAN 10 2015
COOL TEMPERATURES...SOMEWHAT UNSETTLED CONDITIONS AND SNOW COVERED
FUELS WILL KEEP ANY FIRE WEATHER CONCERNS AT BAY THROUGH THE
WEEKEND AND UPCOMING WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CAH
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...CAH
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1010 PM MST SUN JAN 11 2015
...UPDATED AVIATION...
.SYNOPSIS...
UNSETTLED WEATHER WILL CONTINUE TO BE THE STORY THROUGH THE EARLY
PART OF THE WEEK...AS THE LAST TWO IN A SERIES OF FAST MOVING
DISTURBANCES AFFECT THE DESERT SOUTHWEST. SCATTERED SHOWERS WILL
MOVE THROUGH THE AREA INTO THE MORNING HOURS MONDAY...FOLLOWED BY
LINGERING SHOWERS MAINLY ACROSS HIGHER TERRAIN AREAS NORTH AND EAST
OF PHOENIX THROUGH MONDAY AFTERNOON. ANOTHER SYSTEM WILL BRING
CHANCES OF SHOWERS TO EASTERN ARIZONA DURING THE DAYTIME HOURS
TUESDAY. HIGH PRESSURE WILL RETURN TO THE AREA BY MID WEEK WITH DRY
WEATHER AND SLOWLY INCREASING TEMPERATURES EXPECTED FROM WEDNESDAY
INTO NEXT WEEKEND.
&&
.DISCUSSION...
THE PRIMARY PV ANOMALY AND COLD CORE ALOFT HAS MOVED ONSHORE NORTH
OF SAN DIEGO THIS EVENING...WITH A SECONDARY LEAD WAVE/MESO-VORTEX
QUITE EVIDENT IN RADAR AND SATELLITE IMAGERY EJECTING NORTH FROM THE
GULF OF CALIFORNIA. THIS SECONDARY FEATURE APPEARS TO BE IN THE
INITIAL STAGES OF BECOMING ABSORBED BY THE LARGER CIRCULATION
CENTER...HOWEVER ITS PRESENCE IS CREATING ENHANCED UPPER LEVEL
DIFLUENCE AND GREATER OVERALL VORTICITY FORCED ASCENT. PER REGIONAL
MESOANALYSIS...THE LEAD WING OF VORTICITY HAS BEEN ACTING ON A NOSE
OF BETTER LOW LEVEL LAPSE RATES AND FRONTOGENESIS WHILE DEFORMATION
STRUCTURE EXISTS THROUGH SERN CALIFORNIA.
REGIONAL 00Z SOUNDINGS DEPICTING AMPLE MOISTURE AND PWATS BELOW THE
H5 LEVEL (0.7-1.0 INCHES) ALONG WITH RADAR TRENDS SUGGEST PERSISTENT
SHOWERS THROUGHOUT THE OVERNIGHT HOURS. HIGH RESOLUTION MODELS
INCLUDING THE HRRR AND ESPECIALLY 4KM WRF-NMM SEEM TO HAVE THE BEST
SOLUTION BASED ON FORECAST/VERIFIED RADAR REFLECTIVITIES. AS
SUCH...HAVE MADE FURTHER TARGETED INCREASES TO RAINFALL CHANCES
OVERNIGHT...ALBEIT WITH STILL LIGHT ACCUMULATIONS. OTHERWISE WITH
RAINFALL ALREADY REACHING THE SFC AND WETBULBING OCCURRING...HAVE
MADE RATHER SUBSTANTIAL INCREASES TO DEWPOINTS AND RELATIVE
HUMIDITIES OVERNIGHT...WHILE BUMPING UP FORECAST LOWS SLIGHTLY BASED
ON EXTENSIVE THICK CLOUD COVER.
&&
.PREVIOUS DISCUSSION...
/305 PM MST SUN JAN 11 2015/
BY MONDAY MORNING...THE TROUGH IS FORECAST TO BE CENTERED OVER
SOUTH-CENTRAL ARIZONA ALLOWING SHOWERS TO END FOR THE MOST PART
ACROSS SOUTHWEST ARIZONA WITH LINGERING ISOLATED TO SCATTERED
SHOWERS MAINLY FOCUSED OVER THE HIGHER TERRAIN NORTH AND EAST OF
PHOENIX THROUGH MONDAY AFTERNOON. WE SHOULD SEE SOME DRYING AND
CLEARING SKIES IN OUR WESTERN AREAS ON MONDAY...BUT SOME MOISTURE
WILL LINGER OVER ARIZONA AS ANOTHER SHORTWAVE TROUGH APPROACHES FROM
OUT OF THE GREAT BASIN. MODELS HAVE FINALLY COME INTO BETTER
AGREEMENT INDICATING THAT THE LAST TROUGH WILL MAINLY BE A GLANCING
BLOW FOR US...MOSTLY AFFECTING NORTHERN AND FAR EASTERN ARIZONA.
SHOWER CHANCES FOR THIS SYSTEM ARE FOCUSED OVER HIGHER TERRAIN AREAS
EAST OF PHOENIX WITH JUST A SLIGHT CHANCE OVER THE EAST VALLEY. THIS
SYSTEM WILL USHER IN MUCH DRIER AIR BEHIND A COLD FRONT...REACHING
OUR WESTERN AREAS BY NOON TUESDAY AND THEN THROUGH THE REST OF THE
AREA BY LATE TUESDAY AFTERNOON. THIS WILL ALSO BRING SOME GUSTY
WINDS DOWN THE LOWER COLORADO RIVER VALLEY STARTING TUESDAY
AFTERNOON AND THEN INTO SOUTH-CENTRAL ARIZONA TUESDAY NIGHT INTO
WEDNESDAY MORNING. MAY SEE SOME WIND GUSTS TO 35 MPH ALONG RIDGETOPS
AND HIGHER PEAKS...BUT NOT ENOUGH TO WORRY ABOUT ANY WIND ADVISORIES.
LOOKING AHEAD TO WEDNESDAY AND BEYOND...RIDGING WILL RETURN TO THE
AREA BUT NOT NEARLY TO THE EXTENT AS WAS SEEN A FEW DAYS AGO. THIS
SHOULD RESULT IN GRADUALLY INCREASING TEMPERATURES AND LITTLE TO NO
CHANCE OF PRECIPITATION ACROSS THE AREA. HIGHS WILL EVENTUALLY CREEP
BACK INTO THE MID 70S BY LATE WEEK/NEXT WEEKEND.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
NUMEROUS SHOWERS WILL IMPACT TERMINAL SITES THROUGH MONDAY MORNING
WITH CIGS FALLING INTO A 4K-6K FT RANGE. THERE IS A SMALL CHANCE
MVFR VSBY/CIGS COULD BRIEFLY DEVELOP IN PERSISTENT RAINFALL AROUND
12Z...HOWEVER AREAL AND TEMPORAL COVERAGE PRECLUDES A MENTION IN
THIS TAF PACKAGE. WHILE RAIN SHOULD CLEAR EAST AFTER SUNRISE...CIGS
BELOW 6K FT MAY PERSIST INTO THE AFTERNOON. SFC WINDS WILL BE QUITE
VARIABLE...THOUGH UNDER 8 KT WITH DIRECTIONS DICTATED BY
SHOWERS...HOWEVER GENERALLY FAVORING AN EASTERLY DIRECTION UNTIL
MONDAY AFTERNOON THEN WESTERLY THEREAFTER.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
SCT SHOWERS WILL GRADUALLY DISSIPATE BY SUNRISE MONDAY
MORNING...HOWEVER LOWERING CIGS BELOW 6K FT WILL LINGER INTO EARLY
MONDAY AFTERNOON. WHILE CLOUDS WILL PERSIST...SOME LIGHT FOG MAY
ALSO BE POSSIBLE WITH MOISTURE TRAPPED NEAR THE SFC. DID NOT INCLUDE
ANY MVFR VSBY AT THIS TIME. CONDITIONS SHOULD CLEAR BY SUNSET MONDAY
AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
TUESDAY WILL SEE THE FINAL IN A SERIES OF TROUGHS MOVE THROUGH THE
AREA. LOOKS LIKE THE BEST CHANCE OF PRECIPITATION WILL BE IN THE
MOUNTAINS EAST OF PHOENIX. SHOWERS SHOULD TAPER OFF QUICKLY TUESDAY
NIGHT WITH DRY WEATHER FORECAST WEDNESDAY INTO THE WEEKEND. THERE
COULD ALSO BE SOME LOCALIZED BREEZINESS WITH THE TUESDAY SYSTEM
ESPECIALLY DOWN THE COLORADO RIVER AND ACROSS THE RIDGETOPS EAST OF
PHOENIX. NOTHING HIGH ENOUGH TO WARRANT ANY FIRE WEATHER HEADLINES
THOUGH. AS FOR MOISTURE...HUMIDITIES WILL DROP A BIT FROM MID WEEK
ONWARD YET AFTERNOON READINGS WILL ONLY DROP INTO THE 20-30 PERCENT
RANGE WITH GOOD OVERNIGHT RECOVERIES EXPECTED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MO/KUHLMAN/LEINS
AVIATION...MO
FIRE WEATHER...LEINS
AREA FORECAST DISCUSSION
NWS TUCSON AZ
917 PM MST SUN JAN 11 2015
.SYNOPSIS...A PACIFIC SYSTEM WILL BRING A CHANCE OF SHOWERS MAINLY
TONIGHT INTO MONDAY. ANOTHER SYSTEM WILL CONTINUE VALLEY RAIN AND
MOUNTAIN SNOW ESPECIALLY NORTHEAST OF TUCSON MONDAY NIGHT AND
TUESDAY. EXPECT DRY CONDITIONS WEDNESDAY THROUGH SATURDAY. DAYTIME
TEMPERATURES WILL AVERAGE A FEW DEGREES ABOVE NORMAL DURING THE
UPCOMING WEEK.
&&
.DISCUSSION...WATER VAPOR IMAGERY AND 12/00Z UPPER-AIR PLOTS SHOW A
SHORTWAVE TROUGH OVER SOUTHERN CALIFORNIA AND HEADED EASTWARD
THROUGH SOUTHERN ARIZONA TONIGHT THROUGH EARLY MONDAY. THIS EVENINGS
KTWC SOUNDING INDICATED A PRECIPITABLE WATER VALUE OF 0.72 INCHES...
WHICH IS 187% OF NORMAL FOR THIS TIME OF YEAR. SATELLITE DERIVED
BLENDED TOTAL PRECIPITABLE WATER PRODUCT SHOWS AN AREA OF AROUND 1
INCH VALUES OVER SOUTHERN CALIFORNIA...NORTHERN BAJA AND EXTREME
SOUTHWESTERN ARIZONA WHICH IS COINCIDENT WITH THE LATEST RADAR
MOSAIC LOOP THAT SHOWS ISOLATED TO SCATTERED SHOWERS BETWEEN PALM
SPRINGS TO BLYTHE AND EASTWARD ACROSS CENTRAL MARICOPA COUNTY AND
THE NORTHERN SECTIONS OF THE PHOENIX METRO AREA.
CLOSER TO HOME...ISOLATED SHOWERS WILL CONTINUE TO MOVE NORTHEAST
ACROSS CENTRAL AND EASTERN PORTIONS OF PIMA COUNTY IN THE NEAR TERM.
AS THE AFOREMENTIONED LOW CONTINUES TO MOVE EAST OVERNIGHT...EXPECT
SHOWERS TO INCREASE FROM WEST TO EAST WITH THE BEST CHANCE OF
PRECIPITATION OCCURRING LATE TONIGHT AND EARLY MONDAY. RAINFALL
AMOUNTS WILL REMAIN VERY LIGHT...GENERALLY LESS THAN A TENTH OF AN
INCH FOR MOST LOCATIONS. THE LATEST HRRR IS INDICATING THAT THE BULK
OF THE PRECIPITATION WILL LIFT TO THE NORTHEAST ACROSS THE MOGOLLON
RIM AND AREAS FARTHER NORTH TONIGHT...WHILE ISOLATED TO SCATTERED
SHOWERS WILL OCCUR OVER MY FORECAST AREA. HOWEVER...WITH THE LOW
STILL TO OUR WEST AND EXPECTED TO MOVE OVERHEAD...ANY FORCING
ASSOCIATED WITH THIS SYSTEM...ALONG WITH HIGH MOISTURE CONTENT IN
THE ATMOSPHERE FOR THIS TIME OF YEAR WILL HELP TO GENERATE SCATTERED
TO LOCALLY NUMEROUS SHOWERS OVERNIGHT AND EARLY MONDAY. THAT
SAID...WILL MAINTAIN THE POP FORECAST THAT SHOWS A SIGNIFICANT
INCREASE IN SHOWERS MAINLY AFTER MIDNIGHT AND CONTINUING INTO EARLY
MONDAY.
AS OF 04Z (9 PM MST)...TEMPERATURES ACROSS THE REGION RANGED FROM
THE UPPER 40S AT SAFFORD TO 60 DEGS AT THE TUCSON INTL AIRPORT.
THESE READINGS SEEM TO BE ON TRACK WITH THE EXPECTED OVERNIGHT LOW
TEMPS...SO NO CHANGES ARE PLANNED AT THIS TIME...BUT WILL CONTINUE
TO MONITOR.
FOR DETAILS REGARDING THE FORECAST BEYOND MONDAY...PLEASE REFER TO
THE PREVIOUS DISCUSSION BELOW.
&&
.AVIATION...VALID THRU 13/06Z.
A DISTURBANCE OVER SOUTHERN CALIFORNIA THIS EVENING WILL MOVE EAST
THROUGH SOUTHERN ARIZONA AND NORTHERN SONORA TONIGHT AND EARLY
MONDAY...THEN MOVE EAST OF THE AREA BY MONDAY EVENING. SHOWERS WILL
CONTINUE TO DEVELOP WEST OF KTUS THIS EVENING THEN OVERSPREAD MUCH
OF THE AREA TONIGHT INTO MONDAY MORNING. SHOWERS WILL START TO
DECREASE FROM WEST-TO-EAST MONDAY AFTERNOON. AREAS OF MVFR
CONDITIONS WITH MOUNTAIN OBSCURATIONS WILL OCCUR...ESPECIALLY LATE
TONIGHT INTO MONDAY MORNING. OTHERWISE...CEILINGS WILL LOWER TO
AROUND 4-8K FT AGL AFTER 12/06Z AND CONTINUE INTO MONDAY. SURFACE
WIND WILL GENERALLY BE LESS THAN 10 KTS. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A DISTURBANCE MOVING EASTWARD FROM SOUTHERN
CALIFORNIA INTO ARIZONA WILL BRING A GOOD CHANCE OF SHOWERS TONIGHT
INTO MONDAY. THIS DISTURBANCE WILL MOVE EAST OF THE AREA MONDAY
EVENING...BUT ANOTHER LOW PRESSURE SYSTEM WILL BRING A CHANCE OF
SHOWERS NORTHEAST OF TUCSON MONDAY NIGHT AND TUESDAY. DRY CONDITIONS
WILL THEN PREVAIL WEDNESDAY THROUGH SUNDAY. EXPECT LIGHT TERRAIN
DRIVEN WINDS THROUGH TUESDAY...THEN 20-FOOT WINDS WILL BE GENERALLY
FROM THE EAST AT 5 TO 15 MPH WITH OCCASIONALLY STRONGER SPEEDS
WEDNESDAY THROUGH FRIDAY.
&&
.PREV DISCUSSION...A SHORTWAVE TROUGH WILL BRING A GOOD SHOT OF
PRECIPITATION...WITH MOST GUIDANCE HINTING AT BEST ACCUMULATIONS
TUCSON NORTHWARD TONIGHT AND EARLY MONDAY. HAVE UNDERCUT GUIDANCE
WITH RESPECT TO QPF MAINLY FOR CONSISTENCY AND LOW CONFIDENCE IN
THIS SYSTEM BEING A EFFICIENT PRECIP PRODUCER. NEVERTHELESS...WILL
LIKELY SEE GOOD COVERAGE IN MEASURABLE PRECIP ACROSS THE AREA. SNOW
LEVELS WILL REMAIN ABOVE 7500-8000 FT THROUGH THE EVENT WHICH SHOULD
KEEP SNOW ACCUMULATIONS DOWN BELOW ADVISORY FOR MOST OF THE
MOUNTAINS...TO INCLUDE THE CATALINA`S.
THE SECOND TROUGH WILL LIKELY BRING SLIGHTLY COOLER AIR...THOUGH
DON`T SEE MUCH IN THE WAY OF LOWERING OF THE SNOW LEVELS AT THIS
TIME. STILL...COOLER AIR AND ADDITIONAL PRECIP WILL ADD TO SNOW
ACCUMULATIONS...WHICH COULD BRING ACCUMULATIONS UP TO NEAR ADVISORY
LEVELS FOR A FEW LOCATIONS IN THE WHITE MOUNTAINS MONDAY NIGHT INTO
TUESDAY. HOWEVER...AT THIS TIME THINGS LOOK TOO LOCALIZED AND
BORDERLINE TO WARRANT ANY HEADLINES.
AS THINGS CLEAR OUT WEDNESDAY...SURFACE RIDGING WILL BUILD OVER WEST
TEXAS WHICH WILL ALLOW FOR A TIGHTENING OF THE PRESSURE GRADIENT
OVER THE EASTERN HALF OF THE FORECAST AREA. THIS WILL RESULT IN SOME
LOW END BREEZINESS WEDNESDAY NIGHT INTO FRIDAY...ESPECIALLY IN THE
EASTERLY FLOW PRONE AREAS. OTHERWISE...FAIRLY BENIGN PATTERN IN
PLACE THROUGH NEXT WEEKEND.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
CURRENT DISCUSSION...MOLLERE
PREVIOUS DISCUSSION...MEADOWS
FIRE WEATHER/AVIATION...FRANCIS
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NWS KEY WEST FL
330 AM EST MON JAN 12 2015
.DISCUSSION...
SCATTERED SHOWERS DEVELOPED RELATIVELY QUICKLY LATE LAST EVENING AND
CONTINUE TO PERCOLATE OVER THE NEAR AND OFFSHORE ATLANTIC WATERS.
MORE RECENTLY...A CONCENTRATED AREA OF STRONGER SHOWERS WITH A FEW
THUNDERSTORMS HAS FAVORED THE ATLANTIC WATERS WELL SOUTH OF THE DRY
TORTUGAS. UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES IN THE
KEYS ARE IN THE MIDDLE 70S. MODERATE EASTERLY BREEZES ARE BLOWING
...WITH FRESH TO STRONGER SURGES MAINTAINED OVER THE STRAITS AND
EASTERN HALF OF THE SERVICE AREA.
MIMIC IMAGERY OF TOTAL PRECIPITABLE WATERS SHOWS THE ISOLATED TO
SCATTERED SHOWERS ARE CONCENTRATED ALONG THE WESTERN PERIPHERY OF
DEEPER MOISTURE PULLING ACROSS THE KEYS AND SURROUNDING WATERS. LOCAL
AND NEIGHBORING DOPPLER RADAR IMAGERY SHOWS THERE IS CONTINUED
DEVELOPMENT UPSTREAM IN THIS MORE MOIST AIRMASS...BUT REMAIN WEAKER
AND MORE SEPARATED THAT THE INITIAL DEVELOPMENT.
A MID TO UPPER LEVEL TROUGH CURRENTLY IN THE WEST/CENTRAL GULF OF
MEXICO IS EXPECTED TO DAMPEN WHILE LIFTING NORTHEASTERLY TODAY. THIS
WILL MERGE WITH A MORE BROAD TROUGH IN THE NORTHEAST BEFORE EJECTING
FURTHER INTO THE ATLANTIC. LOW SURFACE PRESSURE WILL REPLACE THE
HIGH CURRENTLY LINGERING ALONG THE MID ATLANTIC COAST...AND WILL
BROADEN AND ELONGATE DOWN THE EASTERN SEABOARD BY TONIGHT AND
EXTEND INTO THE EASTERN GULF OF MEXICO. THIS WEAK PRESSURE PATTERN
WILL MEANDER NEAR SOUTH FLORIDA AND THE FLORIDA KEYS AT LEAST INTO
THURSDAY. THEN A FRONT IS PUSHED THROUGH THE REGION BY EARLY FRIDAY
THANKS TO EXPANDING AND STRENGTHENING HIGH PRESSURE ACROSS THE DEEP
SOUTH.
ASIDE FROM ADJUSTING TEMPERATURES UP BY A DEGREE OR TWO FOR THE NEXT
COUPLE OVERNIGHT PERIODS...THERE IS NO GLARING REASON TO ADJUST OUR
NEAR TERM FORECAST FAR FROM WHAT WE HAVE BEEN ADVERTISING THE LAST
FEW FORECAST CYCLES. DECIDED TO KEEP OUR PROBABILITY OF MEASURABLE
PRECIPITATION CLOSE TO THE LATEST GFS NUMERICAL MOS. THE ECMWF SEEMS
A BIT GENEROUS TONIGHT. ALSO...KEPT A SLIGHT CHANCE OF THUNDER TODAY
AND TONIGHT AS LOW AMPLITUDE MID LEVEL ENERGY SLIDES THROUGH THE
AREA. THE OVERALL PROBABILITY OF PRECIPITATION SLIDES BACK TO A
SLIGHT CHANCE TUESDAY AND REMAINS THAT WAY THROUGH THE END OF THE
WEEK THANKS TO A MODERATE EASTERLY BREEZE OVERLAID BY NEARLY ZONAL
MID LEVELS. TOOK THE MENTION OF PRECIPITATION OUT OF THE FORECAST FOR
FRIDAY NIGHT AND SATURDAY ON THE BACK SIDE OF THE FRONT...AND THEN
BROUGHT A SLIGHT CHANCE BACK IN FOR SATURDAY NIGHT ONWARD AS OUR FLOW
DEEPENS ONCE AGAIN FROM THE EAST WITH REBOUNDING MOISTURE.
&&
.MARINE...
THE LOCAL HRRR AND WRF ARE SHOWING HIGHER WINDS FAVORING THE STRAITS
AND EASTERN HALF OF THE NEARSHORE ATLANTIC WATERS AT LEAST THROUGH
MID-MORNING BEFORE TAPERING OFF OVERALL ACROSS THE SERVICE AREA.
DECIDED TO LEAVE THE ADVISORY IN PLACE THROUGH LATE MORNING THERE AND
ALLOW THE MORNING SHIFT TO RE-EVALUATE THE WIND FIELD BEFORE LOWERING
ANY OF THOSE HEADLINES. EXPECT MORE MODERATE EAST TO NORTHEAST
BREEZES THROUGH LATE THURSDAY BEFORE A FRONT BACKS THE WINDS TO THE
NORTH AND ACCELERATES THEM EARLY FRIDAY MORNING. IT IS POSSIBLE THAT
ADVISORY CONDITIONS FOR SMALL CRAFT COULD REDEVELOP LATE THIS WEEK...BUT
IS LIKELY THAT AT LEAST CAUTIONARY HEADLINES FOR SMALL CRAFT ARE ON TAP
FOR THEN.
&&
.AVIATION...12TH/06Z...VFR WILL PREVAIL AT THE EYW AND MTH
TERMINALS. THERE IS CONSIDERABLE UNCERTAINTY WITH RESPECT TO TODAY`S
CHANCE FOR PRECIPITATION AT BOTH TERMINALS. THE INGREDIENTS NECESSARY
FOR CONVECTION ARE AVAILABLE. HOWEVER...TRIGGERS FOR INITIATION
APPEAR LESS PROBABLE THROUGHOUT THE FORECAST PERIOD. FOR NOW...NO
MENTION OF PRECIPITATION AT THE TERMINALS.
&&
.CLIMATE...JANUARY 12TH...ON THIS DATE IN FLORIDA KEYS CLIMATE
HISTORY...IN 1886...THE TEMPERATURE DROPPED TO 41F IN KEY
WEST...SETTING THE DAILY RECORD. THIS ALSO TIES THE COLDEST
TEMPERATURE EVER RECORDED IN KEY WEST. TEMPERATURE RECORDS IN KEY
WEST DATE BACK TO 1872.
&&
.PRELIM POINT TEMPS/POPS...
KEY WEST 80 72 80 71 / 40 40 20 10
MARATHON 80 72 79 71 / 40 40 20 10
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY FOR GMZ042-043-052>055-072>075.
&&
$$
PUBLIC/MARINE.........04
AVIATION/NOWCASTS.....CLR
DATA COLLECTION.......FLING
VISIT US ON THE WEB AT WEATHER.GOV/KEY
FOLLOW US ON FACEBOOK AND TWITTER AT...
WWW.FACEBOOK.COM/NWSKEYWEST
WWW.TWITTER.COM/NWSKEYWEST
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
342 AM CST Mon Jan 12 2015
.SHORT TERM...(Today)
ISSUED AT 341 AM CST MON JAN 12 2015
No changes planned to the winter weather advisory with the 4 am
package. We will just clear out the western counties as precip ends
and conditions warrant as the morning progresses. The back edge of
the precip is becoming more diffuse, but another trailing band of
snow is still approaching from SE Iowa and N Missouri. Forecast
soundings show we will be losing our ice crystals aloft this
morning, which could cause the light snow to change to freezing
drizzle. Over the next 3-5 hours, we could see a few tenths of an
inch of snow accumulate from the band of snow from Jacksonville to
Bloomington progressing east. The dual pol radar images show the
precip change to all snow clearly, with the leading edge of snow
from Springfield to northwest Champaign county at 09z/3am. Just
ahead of the change-over from rain to snow, there have been reports
of freezing rain and sleet from Champaign to Taylorville, so some
light glazing will still be possible before the rain changes to
completely to snow.
Areas southeast of I-70 could see temps hold just above freezing
until sunrise, and then remain hovering just above freezing until
later morning behind the cold front. So precip would just change
from rain to snow. The main freezing conditions in that area would
be due to the frozen ground freezing rain on untreated surfaces.
Falling temps are expected this afternoon across the board, as NW
winds of 15 gusting to 25 mph usher our next wave of unseasonably
cold air. The HRRR is advertising a rapid clearing of clouds this
morning from NW to SE, which seems a little ahead of satellite
trends. We will delay clearing until later morning in the west, then
progress to all but the far southeast this afternoon.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 341 AM CST MON JAN 12 2015
Tonight the weather quiets down again with high pressure building
back into the Midwest and controls the weather through the week.
Roughly mid week as a synoptic wave digs into the desert SW, flow
over the eastern half of the country moves from more zonal to a more
amplified pattern. Northwesterly flow over the region will move a
short wave through the region as well... and although the models are
currently dry under the surface ridge...will need to watch the
strength of the wave and its persistence for some flurry potential
Wednesday afternoon/evening. Other than that...temps this week
starting out below normal but slowly warming through the end of the
week as more southwesterly flow at the sfc maintains WAA through the
forecast. Next system is starting to have some issues with
consistency for the weekend. Prev GFS originated the system out of
the SW, a result of the bigger wave from earlier in the week. The
most recent ECMWF is weaker with the southern stream/wave...and
instead, develops the sfc system from a shortwave moving across the
nrn tier of the country. With perpetual waa ahead of the system,
have maintained the precip for Sun night and into Monday for rain.
But, with the details so divergent at this point, keeping the
forecast conservative. A more northerly stream system may end up
with more of a precip type decision as the time approaches. A
little too early to call and expect some variability.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1105 PM CST SUN JAN 11 2015
LIFR to occasional VLIFR cigs/vsbys will prevail thru the early
morning hours over most of our forecast area with an improving
trend setting in around 12z across the PIA area and by 16z in CMI
with VFR conditions expected for the remainder of the forecast
period. Surface temperatures have been about a degree warmer than
what we expected over central IL and points southeast where mostly
rain has occurred. However, as a cold front slips across the area,
it appears the precip will transition over to some light freezing
rain or drizzle and then light snow before all the precip shifts
off to the east of the TAF sites by 15z Monday. Some rather low
vsbys expected at times for the next 3-5 hours with fog mixed in
with the occasional precip with mostly snow now expected over BMI
and PIA, and a wintry mix over in CMI and rain changing over to
some light freezing drizzle and then light snow before ending
Monday morning. Surface winds will remain light south to southwest
but are still expected to shift into the north around 06z at PIA
and by 09z over in CMI. North winds of 12 to 17 kts are expected
on Monday with a few gusts around 23 kts at times, especially
during the afternoon. Look for north winds of 10 to 15 kts thru
Monday evening.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 9 AM CST this morning FOR
ILZ042>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...HJS
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1218 AM EST MON JAN 12 2015
.SYNOPSIS...
ISSUED AT 438 PM EST SUN JAN 11 2015
A STORM SYSTEM MOVING UP THE OHIO VALLEY TONIGHT WILL COMBINE
WITH A COLD FRONT DROPPING SOUTHEAST ACROSS THE GREAT LAKES WILL
CAUSE SNOW TO OVERSPREAD OUR AREA FROM SOUTH TO NORTH THIS
EVENING. THE SNOW WILL CONTINUE ACROSS THE AREA OVERNIGHT BEFORE
TAPERING OFF FROM NORTHWEST TO SOUTHEAST MONDAY MORNING. SNOW
WILL BE MIXED WITH SLEET AND FREEZING RAIN SOUTH OF ROUTE 24.
TOTAL SNOW ACCUMULATIONS ARE EXPECTED TO BE 2 TO 4 INCHES. LOW
TEMPERATURES WILL BE IN THE UPPER 20S TONIGHT. TEMPERATURES WILL
FALL THROUGH THE AFTERNOON ON MONDAY...REACHING THE SINGLE DIGITS
ABOVE TO SINGLE DIGITS BELOW ZERO BY TUESDAY MORNING.
&&
.UPDATE...
ISSUED AT 850 PM EST SUN JAN 11 2015
FORECAST LOOKS IN GOOD SHAPE AT THE MOMENT PER LATEST
OBSERVATIONS AND REPORTS. HIRES GUIDANCE SURFACE TEMPS LOOK TO BE A
COUPLE DEGREES TOO COLD ACROSS THE SOUTHEAST WITH RUC13 AND HRRR
SHOWING TEMPERATURES AT 02Z OF 28 TO 29 DEGREES WHERE SFC
OBSERVATIONS ARE 31 TO 33. 01Z RUC WHICH JUST CAME IN IS NOW A
DEGREE WARMER. A CALL TO PORTLAND AWOS AROUND 0130Z INDICATED SNOW
AND 33F WITH THE HIGHER RETURNS THAT MOVED THROUGH THAT AREA. SO
FAR SPOTTER REPORTS INDICATE A TENTH OF AN INCH OR LESS OF ICE IN
THE SOUTH WITH A MIX OF SLEET AND SNOW AT TIMES WITH HEAVIER
RETURNS. LATEST HI RES WARM T LAYER TEMPS HAVE LOWERED TO 0C OR
COLDER BUT GUIDANCE IS WARMING THESE TO BETWEEN 2 AND 2.5C IN THE
FAR SOUTHEAST BY 04-06Z WITH NEXT WAVE OF PCPN IN CENTRAL INDIANA
COMING NORTHEAST. THIS COULD BRING ADDITIONAL FZRA BACK TO THIS
AREA. INTERESTING TO NOTE THAT ONLY MODEL TO REALLY CAPTURE 02Z
SFC TEMPS IN THE SOUTHEAST WAS LOCAL 12KM WRF. THIS MODEL BRINGS
SFC TEMPS UP TO AROUND 33 TO 34 WITH NEXT SURGE OF HEAVIER PCPN.
THIS MAY BE OVERDONE WITH RATHER UNIFORM TEMPS AROUND 31 TO 32
ACROSS CENTRAL INDIANA. REGARDLESS...CURRENT ADVISORY LOOKS ON
TRACK WITH MIX OF PCPN CONTINUING IN THE SOUTH AND SOUTHEAST.
TRANSITION TO SNOW CENTRAL AND NORTH. REPORTS ANYWHERE FROM AN
INCH CENTRAL TO NEAR 3 INCHES IN BERRIEN COUNTY ALONG LAKESHORE.
RADAR MOSAIC SHOWING DRY SLOT TRYING TO FILL IN. HIRES GUIDANCE
WANTS TO SINK FGEN FORCED AREA OF LIGHT SNOW CURRENTLY TO OUR
NORTHWEST SOUTH ACROSS THE AREA OVERNIGHT. THIS SEEMS REASONABLE
AND SHOULD THEN END MONDAY MORNING FROM NORTHWEST TO SOUTHEAST. NO
SIGNIFICANT CHANGES PLANNED TO SNOW AMOUNTS. PREVIOUS UPDATE
INCREASED ICING AMOUNTS TO BETWEEN ONE AND TWO TENTHS AND THIS
ALSO STILL ON TARGET FOR NOW. WILL CONTINUE TO MONITOR HIRES
GUIDANCE TRENDS WITH NEXT BATCH OF HEAVIER PCPN.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 314 PM EST SUN JAN 11 2015
MAIN FOCUS REMAINS SNOW AMOUNTS AND PTYPE INTO TONIGHT/MON AM...
GOOD MOISTURE CONVERGENCE IN 900-700 MB LAYER EXPECTED TO
OVERSPREAD THE AREA LATE AFTN/EVE AS A SHORTWAVE OVER MISSOURI
SHEARS NORTHEAST INTO LOWER LAKES CONFLUENT ZONE. THE RESULTING
FGEN RESPONSE AND SURGE OF MOISTURE IN WARM CONVEYOR BELT (PWATS
> 0.70 INCHES AND 1000-850 MB MIXING RATIOS APPROACHING 4 G/KG
SERN HALF) UNDER THE RIGHT ENTRANCE REGION OF A 150 KT UPPER JET
WILL SUPPORT A MODERATE PCPN EVENT INTO THE EARLY OVERNIGHT.
DEEPER MOISTURE AND HEAVIER PCPN WILL EXIT THE AREA
OVERNIGHT/MONDAY MORNING BUT STILL EXPECT A BAND OF LIGHT SNOW TO
SINK SE THROUGH THE AREA MONDAY MORNING AS A MORE PRONOUNCED
NORTHERN STREAM SHORTWAVE REINVIGORATES FGEN ALONG LINGERING
BAROCLINIC ZONE.
PTYPE EXPECTED TO BE MAINLY SNOW (MAYBE A BRIEF MIX AT ONSET) NW
OF HWY 24 WITH SLEET AND FREEZING RAIN LIKELY MIXING IN TO THE
SOUTHEAST THIS EVENING AS WEAK WARM LAYER ALOFT LIFTS IN. THIS
WARM THERMAL PROFILE WILL LIKELY LIMIT SNOW RATIOS TO NEAR/JUST
BELOW CLIMO...ESPECIALLY SERN ZONES WHERE WINTRY MIX IS EXPECTED.
SNOW TOTALS GRIDDED UP BASED ON RELATIVELY CONSISTENT QPF AND
10-12:1 RATIOS ONCE AGAIN CAME TO BETWEEN 2-4" MOST LOCATIONS.
THERE REMAINS CONCERN FOR MESOBANDING AND LOCALLY HEAVIER AMOUNTS
GIVEN STEEPER LAPSE RATES/REDUCED STATIC STABILITY MODELED JUST
ABOVE THE FRONTAL SLOPE...ALTHOUGH BANDS EXPECTED TO BE TRANSIENT
FOR THE MOST PART KEEPING TOTALS IN CHECK. HEAVIER PRECIP RATES
AND POTENTIAL FOR SOME LIGHT ICING SE OF HWY 24 WARRANTED A
WINTER WX ADVISORY.
&&
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 314 PM EST SUN JAN 11 2015
RATHER BENIGN PATTERN TO PREVAIL FOR MUCH OF THE LONG TERM
PERIOD. FORECAST PERIOD TO BEGIN WITH HIGH PRESSURE BUILDING INTO
THE REGION BRINGING SHALLOW ARCTIC INTRUSION WITH IT. HIGH
PRESSURE CENTER WILL MOVE OVER THE AREA BY TUESDAY
NIGHT...YIELDING CLEAR SKIES LIGHT WINDS...AND WITH SNOW COVER
IDEAL RADIATIONAL COOLING WILL SEND LOWS BELOW ZERO FOR WEDNESDAY
MORNING. REST OF THE WEEK WILL FEATURE GRADUAL WARMING TREND AS
OVERALL PATTERN TRENDS MORE TOWARD A ZONAL FLOW. SPLIT FLOW WILL
HAVE SYSTEM MOVING ACROSS THE US/CANADIAN BORDER WHILE SOUTHERN
STREAM WAVE MOVES THROUGH THE GULF COAST STATES ON
THURSDAY...LEAVING OUR AREA IN BETWEEN AND DRY. MEDIUM RANGE
MODELS INDICATING STRONG JET DYNAMICS STREAMING IN FROM THE
PACIFIC INTO THE WEST COAST THAT WILL INDUCE SOME DOWNSTREAM
RIDGING AND ALSO LEAD TO A FLATTENING OF THE PATTERN AND A BROAD
ZONAL FLOW ACROSS THE CONUS. WARMING TREND WILL ENSUE GOING INTO
THE WEEKEND WITH TEMPS AOA NORMAL BY SATURDAY. MOS GUIDANCE
TRENDING POPS TOWARD CLIMO BY THE END OF THE PERIOD AS ONE WOULD
EXPECT...BUT NOT SEEING INDICATION THAT MODELS ARE CONVERGING
TOWARD A SOLUTION THAT WOULD WARRANT INTRODUCING POPS ATTM SO
WILL MAINTAIN DRY FCST THRU THE PERIOD FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1213 AM EST MON JAN 12 2015
-SN WITH IFR CONDITIONS SHOULD CONT ACROSS NRN INDIANA OVERNIGHT
AS A SHRTWV MOVES EAST FROM MO. SFC CDFNT ASSOCIATED WITH A NRN
STREAM TROF DROPPING INTO THE UPR GRTLKS SHOULD ALSO MOVE THROUGH
NRN INDIANA THIS MORNING... WITH DRIER NORTHERLY FLOW IN ITS WAKE
BRINGING -SN TO AN END. MVFR LOW CLOUDS SHOULD PERSIST THROUGH
THE DAY AS MOISTURE REMAINS TRAPPED BENEATH A LOW LEVEL INVERSION...
WITH CIGS CLEARING OUT TONIGHT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR INZ026-027-
032>034.
WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR INZ020-
022>025.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR OHZ016-024-025.
LM...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 4 AM EST TUESDAY
FOR LMZ043-046.
&&
$$
UPDATE...LASHLEY
SYNOPSIS...MURPHY
SHORT TERM...STEINWEDEL
LONG TERM...JAL
AVIATION...JT
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 MARQUETTE MI
501 AM EST MON JAN 12 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST MON JAN 12 2015
WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROF EXTENDING FROM SRN HUDSON
BAY TO MN...AND LATEST RUC ANALYSIS SHOWS 850MB THERMAL TROF WITH
TEMPS OF -20 TO -28C APPROACHING NW LAKE SUPERIOR ATTM. AT THE
SFC...ASSOCIATED COLD FRONT EXTENDS FROM NEAR KIWD E TO NEAR
WHITEFISH PT. DESPITE APPROACHING SHORTWAVE TROF AND FAIRLY DECENT
DEEP LAYER FORCING PER QVECTORS...LES OVER LAKE SUPERIOR HAS NOT
SHOWN MUCH CHANGE IN INTENSITY OVERNIGHT. LACK OF MUCH REFLECTIVITY
AOA 28DBZ SUGGESTS SNOW IS MOSTLY LIGHT TO OCCASIONALLY MDT.
WITH DEEP LAYER FORCING THRU ABOUT MID MORNING AND INCREASING
OVERWATER INSTABILITY...EXPECT SOME UPTICK IN LES OVER THE NEXT
SEVERAL HRS. THIS INCREASE SHOULD BE MORE APPARENT OVER FAR WRN
UPPER MI (GOGEBIC/ONTONAGON COUNTIES) AS SHARPER LOW-LEVEL
CONVERGENCE DEVELOPS THERE FOR A SHORT TIME...AND THEN ALSO OVER
NCNTRL UPPER MI (MARQUETTE/ALGER COUNTIES) WHERE A MORE CONVERGENT
NRLY FLOW DEVELOPS. LONGER FETCH AND DEEPER DGZ WILL ULTIMATELY LEAD
TO GREATEST SNOW ACCUMULATIONS IN NCNTRL UPPER MI...ROUGHLY IN THE
AREA BTWN NEGAUNEE AND MUNISING WHERE SNOW ACCUMULATIONS OF 2-4
INCHES WILL BE PAINTED TODAY. 2-3 INCHES ARE POSSIBLE FROM KIWD TO
THE PORCUPINE MTNS. OTHERWISE...SNOW ACCUMULATIONS ACROSS THE REST
OF THE FCST AREA NEAR LAKE SUPERIOR SHOULD BE ON THE ORDER OF AN
INCH OR TWO TODAY. THIS AFTN...STRONG DEEP LAYER QVECTOR DIVERGENCE
IN THE WAKE OF SHORTWAVE AND CORRESPONDING LOWERING OF INVERSION
COMBINED WITH INCREASINGLY ANTICYCLONIC 925MB FLOW AHEAD OF STRONG
ARCTIC HIGH PRES BUILDING INTO THE PLAINS/UPPER MISSISSIPPI VALLEY
WILL LEAD TO DIMINISHING LES COVERAGE/INTENSITY. BRIEF SHOT OF
ARCTIC AIR WILL LEAD TO A COLDER DAY TODAY. EXPECT HIGHS IN THE 5 TO
15 RANGE...COLDEST W.
CENTER OF ARCTIC HIGH PRES WILL MOVE INTO THE WRN GREAT LAKES
TONIGHT. MODERATING 850MB TEMPS AND BACKING WINDS WILL BRING AN END
TO ANY LINGERING LIGHT LES OVER NW UPPER MI EARLY THIS EVENING. LAST
OF THE LES OVER NCNTRL UPPER MI SHOULD SHIFT OFFSHORE BY 06Z.
CLEARING SKIES/DRY COLUMN AND CALM WIND FOR MUCH OF THE AREA FOR
MOST...IF NOT ALL...OF THE NIGHT WILL LEAD TO EXCELLENT RADIATIONAL
COOLING. FAVORED THE LOWEST GUIDANCE WHICH IS THE GLOBAL GEM BIAS
CORRECTED. AS IT HAS FOR THE LAST FEW DAYS...IT SHOWS MINS AS LOW AS
THE LOW TO MID -20S IN THE INTERIOR W HALF TONIGHT. THIS MATCHES UP
FAIRLY WELL WITH CURRENT UPSTREAM TEMPS ACROSS SRN SASKATCHEWAN/SRN
MANITOBA. WOULD NOT BE SURPRISED TO SEE THE COLDEST OF THE
TRADITIONAL COLD SPOTS BOTTOM OUT AROUND -25F TONIGHT. THE ONLY AREA
THAT MIGHT NOT SEE TEMPS FALL BLO ZERO TONIGHT IS OVER THE TIP OF
THE KEWEENAW.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 456 AM EST MON JAN 12 2015
GENERALLY GOOD AGREEMENT FM THE MODELS IN LARGER SCALE PATTERN
EVOLUTION INTO NEXT WEEKEND AS DEEP TROUGH OVER EASTERN CANADA AND
GREAT LAKES SLOWLY UNRAVELS LEADING TO ZONAL FLOW AND TEMPS NUDGING
TOWARD NORMAL OR EVEN SLIGHTLY ABOVE. THAT IS THE LONG AND SHORT OF
IT...BUT DETAILS ARE MUDDLED AND MAINLY HAVE TO DO WITH SOUTHERN
EXTENT OF SERIES OF SHORTWAVES/SFC TROUGHS LATE THIS WEEK AS THE
PATTERN TRIES TO BECOME MORE ZONAL. STILL LOOKS LIKE A PRETTY GOOD
BET THAT TEMPS WILL EXCEED 30 DEGREES IN SOME PART OF THE CWA
THURSDAY INTO SATURDAY. NEXT SATURDAY IS A GOOD CANIDATE FOR THAT
WARM DAY AS IT APPEARS STRONGER SFC LOW TRACKS NORTH OF UPR
MICHIGAN...PLACING THE AREA IN A MORE DEVELOPED WARM SECTOR. WARM IS
RELATIVE AT THIS POINT. MIXING TO 925-900MB SUPPORTS HIGHS WELL INTO
THE 30S. THAT WOULD BE A PROVERBIAL HEAT WAVE COMPARED TO THE CHILL
THAT HAS BEEN OVER THE UPPER GREAT LAKES SINCE JUST BEFORE THE NEW
YEAR BEGAN.
FORECASTED PATTERN HOLDS MINIMAL CHANCE FOR MUCH IN WAY OF HIGH
IMPACT WEATHER. AFTER A DAY WITH A COLD START BUT PLENTY OF SUNSHINE
ON TUESDAY...COULD BE SOME WIDESPREAD LGT SNOW OVER THE AREA TUESDAY
NIGHT WEST/CENTRAL INTO WEDNESDAY MORNING EAST DUE TO SHORTWAVE
TROUGH AND ASSOCIATED MID- LEVEL WARM AIR ADVECTION. NAM AND GFS SHOW
MOST QPF AS THEY ARE MOST SATURATED BLO H85...BUT STILL ONLY LOOKING
AT LESS THAN 2 INCHES OF SNOW DUE TO LIMITED MOISTURE AND NOT EVEN 6
HOURS OF STEADY SNOW. EXCEPTION MAY BE OVER THE NORTHERN KEWEENAW AS
H9 TEMPS ARE ALREADY -14C WITH AN ONSHORE WSW FLOW AS BETTER FORCING
CROSSES THE AREA. MIGHT SEE LAKE ENHANCEMENT AT LEAST BRIEFLY BEFORE
WINDS VEER NORTHWEST ON WEDNESDAY MORNING. STEADILY VEERING WINDS
SHOULD KEEP CAP ON AMOUNTS VIA LAKE ENHANCEMENT. TEMPS TUESDAY NIGHT
INTO WEDNESDAY MORNING TRICKY WITH NON-DIURNAL CURVE EXPECTED DUE TO
INCREASING CLOUDS LATER AT NIGHT AS THE SYSTEM MOVES THROUGH. ONLY A
WEAK COLD FRONT PASSAGE ON WEDNESDAY...MAINLY AFFECTING THE KEWEENAW.
SOUNDINGS EVEN THERE THOUGH LOOK LESS FAVORABLE AS DAY WEARS ON WITH
DRYING ABOVE H875 AND INVERSIONS LESS THAN 5KFT. KEPT CHANCES GOING
SINCE DELTA T/S WILL BE ABOVE 15C...BUT NEGATIVE FACTORS SHOULD
HAMPER ADDITIONAL LAKE EFFECT SNOW SHOWERS. TEENS TO LOW 20S FOR
HIGHS ON WEDNESDAY.
NW FLOW ALOFT RESULTS IN ANOTHER SHORTWAVE AND SFC TROUGH CROSSING
LK SUPERIOR AND MAINLY NORTHERN UPR MICHIGAN ON WEDNESDAY NIGHT.
STRONGER FORCING AND GREATEST CHANCES FOR SNOW WILL BE OVER NORTHERN
ONTARIO CLOSER TO DEEPENING SFC LOW TRACKING TOWARD JAMES BAY. SETUP
OVER CWA SIMILAR TO TUE NIGHT WITH BEST MOISTENING/LIFT OCCURRING
ALOFT ROUGHLY H85-H6. SLIGHT CHANCES ALL AREAS...BUT ONLY CARRIED
CHANCE POPS ON KEWEENAW DUE TO HIGHER 1000-850MB RH WITH ONSHORE
WSW-W WINDS PROVIDING POSSIBLE ADDITIONAL MOISTURE. WARMING TREND
BEGINS TO BE NOTED WITH MINS WED NIGHT MOSTLY 10 ABOVE OR HIGHER
OVER ALL CWA. LAST WEEK IT WAS A STRUGGLE TO REACH 10 ABOVE FOR A
HIGH TEMPERATURE. SFC LOW CONTINUES EASTWARD AND A SW-W WIND SHOULD
STAY IN PLACE OVER UPR MICHIGAN. SMALL CHANCES ESPECIALLY NORTH AND
EAST BUT DRYING TREND SHOULD WIN OUT BY AFTN. SOUNDINGS SHOW MIXING
TO H925...WHICH ALLOWS MOST AREAS TO REACH WELL INTO THE 20S AND
SOME SPOTS TO POSSIBLY CRACK 30 DEGREES.
MODELS HAVE STEADILY TRENDED TO LESS AND LESS COLD AIR INTRUSION FOR
COLD FRONT PASSAGE ON THU NIGHT INTO FRIDAY. H925/H85 TEMPS AT 12Z
FRIDAY STILL COOLER OFF GFS AT -10C/-8C BUT ECMWF IS REALLY TRENDING
WARMER WITH VALUES ONLY -4C/-6C. GEM-NH LOOKS LIKE THE WARMER ECMWF.
ALTHOUGH LES LOOKS UNLIKELY...GFS/ECMWF/GEM-NH INDICATE SHORTWAVE
DROPPING THROUGH IN WNW FLOW ALOFT ALONG WITH SOME FORCING AND
MOISTURE ALONG COLD FRONT THAT ATTEMPTS TO DROP SOUTHWARD TOWARD
UPR MICHIGAN. LOW CHANCE POPS...NOT SURE ON THE TIMING AS MODELS
DIFFER...SEEM REASONABLE OVER THE NORTH CWA DUE TO THESE SIGNALS.
AS ALLUDED TO BEFORE...MODEL DIFFERENCES CONTINUE INTO NEXT WEEKEND
WITH REGARD TO HOW FAR SOUTH ANOTHER LOW PRESSURE TROUGH CROSSES THE
AREA. EARLIER RUNS OF ECMWF WERE MORE AGGRESSIVE IN A FARTHER SOUTH
TRACK TO LOW BUT LATEST RUNS ARE MORE LIKE THE GFS AND GEM-NH WITH
SFC LOW AND MOST PRECIP STAYING NORTH OF UPR MICHIGAN OR AT LEAST
DELAYED INTO UPR GREAT LAKES. DID NOT STRAY TOO MUCH FM CONSENSUS
GUIDANCE FOR NEXT WEEKEND...BUT WITH THE TREND FM ECMWF...HEADED
TOWARD WARMER TEMPS INTO THE 30S MOST AREAS ON SATURDAY WITH
EXPECTATION THAT CWA WILL BE WITHIN WARM SECTOR MOST OF THE DAY.
INTERESTING THAT MEX GUIDANCE /EXTENDED GFS MOS NUMBERS/ CHECKS
IN AT 33-40F FOR NEXT SATURDAY OVER THE CWA. CLIMO IN THE LOW-MID
20S...SO THAT IS A DECENT DEPARTURE FM AVERAGE AT A POINT IN MOS
WHERE THERE IS USUALLY A BIAS BACK TOWARD CLIMO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1222 AM EST MON JAN 12 2015
CMX...AS WINDS VEER TO THE NNW BEHIND A COLD FRONT AND MORE
FAVORABLE INSTABILITY DEVELOPS WITH AN UPPER LEVEL DISTURBANCE
MOVING IN...EXPECT LOWER END MVFR CIGS AND VSBY DROPPING TO IFR LATE
IN THE NIGHT. CONDITIONS ARE THEN EXPECTED TO REMAIN MAINLY IN THE
MVFR RANGE THROUGH THE REST OF THE FCST PERIOD. EVEN THOUGH THE LES
WILL TAPER OFF...A LOWERING INVERSION IS EXPECTED TO KEEP CIGS IN
THE MVFR RANGE THIS EVENING.
IWD...VFR CONDITIONS WILL PERSIST UNTIL VEERING WINDS TO NNW
PUSH LAKE EFFECT SNOW SHOWERS INTO THE AREA AROUND/AFTER 08Z.
LOOK FOR NEAR IFR CEILING/VIS TO LINGER THROUGH 18Z TODAY.
IMPROVEMENT IS EXPECTED THIS AFTERNOON AS DRY AIR AND ANTICYCLONIC
UPSTREAM FLOW DEVELOPS.
SAW...WITH WINDS SHIFTING TO THE N...-SHSN WILL MOVE IN OFF LAKE
SUPERIOR...AND IFR CONDITIONS ARE EXPECTED BY DAYBREAK AS BETTER
CONVERGENCE SETS UP ON MAINLY N FLOW OFF LAKE SUPERIOR BEHIND THE
PASSING COLD FRONT. WITH DRIER AIR MOVING IN DURING THE AFTERNON AND
BACKING WINDS...CONDITIONS SHOULD IMPROVE TO MVFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 456 AM EST MON JAN 12 2015
TYPICALLY STRONG WINDS FOR WINTER EXPECTED MUCH OF THIS LAST WEEK OF
THE SHIPPING SEASON. NORTH WINDS TO 30 KTS THIS MORNING DIMINISH TO
LESS THAN 20 KTS BRIEFLY TONIGHT. WITH A SURGE OF ARCTIC AIR AND
BUILDING WAVES...EXPECT A PERIOD OF HEAVY FREEZING SPRAY OVER MUCH
OF THE LAKE IN LINE WITH GOING WARNINGS. WINDS RAMP UP TO 30 KTS FM
THE WEST OR SOUTHWEST TUESDAY AND TUESDAY NIGHT AHEAD OF AN COLD
FRONT. STRONGEST WINDS OVER WESTERN LK SUPERIOR...AND CANNOT COUNT
OUT A PERIOD OF GALES BTWN ISLE ROYALE AND THE KEWEENAW LATE
TUESDAY. ADDITIONAL HEAVY FREEZING SPRAY IS POSSIBLE OVER WESTERN LK
SUPERIOR DURING THIS TIME. COLD FRONT SLIDES OVER THE LAKE ON
WEDNESDAY AND WINDS SETTLE DOWN TO LESS THAN 25 KTS BY WEDNESDAY
AFTN. LULL IS BRIEF AS WEST WINDS INCREASE TO 25-30 KTS BY THURSDAY
MORNING OUT AHEAD OF ANOTHER COLD FRONT THAT DROPS OVER LK SUPERIOR
ON FRIDAY. THOUGH WINDS DIMINISH TO LESS THAN 25 KTS LATER ON
FRIDAY...WINDS INCREASE AGAIN BY NEXT SATURDAY FM THE SOUTH OUT OF
AN APPROACHING LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ248>251-265>267.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR LSZ162.
HEAVY FREEZING SPRAY WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
LSZ243-244-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR LSZ241-242-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
346 AM EST MON JAN 12 2015
.SHORT TERM...TODAY AND TONIGHT
AFTER A LULL IN THE SNOW SHORTLY AFTER MIDNIGHT...TRENDS IN THE
RADAR AND SFC OBS ARE SHOWING A REINTENSIFICATION OF SNOWFALL ACROSS
NRN INDIANA INTO SE MI. THIS IS THE RESULT OF A RENEWED
STRENGTHENING OF SOME MID TROPOSPHERIC FRONTAL FORCING /IN THE 800-
700MB LAYER/ AND WILL TARGET LOCALS SOUTH OF A SANDUSKY TO OWOSSO
LINE EARLY THIS MORNING. THE FRONTAL CIRCULATION WILL ADVANCE TO THE
EAST DURING THE COURSE OF THE MORNING AS THE UPPER JET SUPPORT
SLIDES EAST OF THE STATE. THE CURRENT NAM AND SEVERAL HI RES
SOLUTIONS SUGGEST THE FORCING WILL WEAKEN AS IT HEADS EAST OF METRO
DETROIT BETWEEN 12Z AND 15Z THIS MORNING. SNOWFALL INTENSITY WILL
FLUCTUATE DURING THE MORNING AS THE STRENGTH OF THE MID LEVEL LIFT
VARIES. IN LIGHT OF THE FORCING AND PROJECTED NEAR TERM QPF
AMOUNTS...ADDITIONAL SNOWFALL ACCUMS BETWEEN A HALF INCH AND INCH
THROUGH DAYBREAK STILL SEEM REASONABLE. BASED ON REPORTS PRIOR TO
MIDNIGHT...THIS SHOULD LEAD TO TOTAL SNOWFALL SOUTH OF A BAD AXE TO
SAGINAW LINE OF 1 TO 3 INCHES. THE HIGHER TOTALS WILL OCCUR ACROSS
THE NRN DETROIT SUBURBS WHERE FORCING WAS A LITTLE MORE PERSISTENT
OVERNIGHT. THERE IS A SECONDARY REGION OF RADAR RETURNS PUSHING
SOUTH ACROSS NRN LOWER MI...OCCURRING ALONG THE 600-500MB PORTION OF
THE FRONT. THE FORCING IS EXPECTED TO WEAKEN AS IT ENTERS THE
SAGINAW VALLEY AND THUMB EARLY THIS MORNING. UPSTREAM RETURNS
HOWEVER SUPPORT AT LEAST CHANCE POPS ACROSS THE NRN THIRD OF THE
FORECAST AREA THIS MORNING. UNTREATED ROADS WILL BE VERY SLICK THIS
MORNING AS THIS SNOW HAS A HIGH WATER CONTENT. WITH TEMPS IN THE
UPPER 20S...ROAD TREATMENTS SHOULD PROVE HIGHLY EFFECTIVE.
WHILE THE COLD FRONT WILL MOVE EAST OF THE AREA EARLY THIS
MORNING...THE PUSH OF ARCTIC AIR WILL NOT ARRIVE INTO SE MI UNTIL
THIS AFTERNOON UNDER STRENGTHENING NORTHERLY WINDS. THIS WILL
SUPPORT MORNING HIGHS /MID 20S TO LOW 30S/...WITH FALLING TEMPS
DURING THE AFTERNOON. WHILE THE MID LEVEL TROUGH AXIS NOW
APPROACHING LAKE SUPERIOR WILL NOT TRAVERSE SE MI UNTIL THIS
EVENING...LARGE SCALE SUBSIDENCE WITHIN THE DESCENDING BRANCH OF THE
MID TROP FRONT WILL LEAD TO SUBSTANTIAL MID LEVEL DRYING THIS
AFTERNOON. THIS WILL KEEP CONDITIONS PRECIP FREE OUTSIDE OF SOME
LAKE EFFECT SNOW SHOWERS OVER THE THUMB REGION UNDER NORTHERLY FLOW.
THE NAM AND 4KM WRF NMM SHOW A DOMINATE LAKE BAND DEVELOPING OVER
THE SRN LAKE HURON BASIN THIS EVENING. THE COLD AIR ADVECTION WILL
BE SHALLOW...SUPPORTING EQUILIBRIUM LEVELS ONLY TO 5K FT.
HOWEVER...STEEP LOW LEVEL LAPSE RATES WITH TEMPS OF -16 TO -18C NEAR
THE NEAR THE TOP OF THE MIXED LAYER COULD LEAD TO SOME GOOD SNOWFALL
RATES. A GRADUAL BACKING OF THE FLOW TO THE NNE AIDED BY A LAND
BREEZE PUSH OFF ONTARIO MAY BRING THIS BAND INTO THE ERN THUMB AND
PORT HURON. WILL KEEP ANY ACCUMS MINOR ATTM /AN INCH OR TWO IN PORT
HURON/. LAKE STRATO CU SHOULD PUSH INTO PORTIONS OF FLINT AND METRO
DETROIT TONIGHT. NAM AND RUC SOUNDINGS SHOW GOOD SUPERSATURATION
WITH RESPECT TO ICE AROUND -16C. THIS MAY BE SUPPORTIVE OF SOME
FLURRIES/LIGHT SNOW SHOWERS OUT OF THE STRATO CU. REGIONS THAT SEE
THE CLOUDS TONIGHT WILL HAVE MIN TEMPS HOLD IN THE SINGLE
DIGITS...WHILE LOCALS ACROSS THE WRN HALF OF THE FORECAST AREA
SHOULD DECOUPLE ENOUGH TO SUPPORT SUB ZERO MINS.
&&
.LONG TERM...TUESDAY THROUGH SUNDAY
STRONG SURFACE HIGH PRESSURE WILL REMAIN SPRAWLED OVER THE GREAT
LAKES TUESDAY AND TUESDAY NIGHT. THIS WILL BRING QUIET WEATHER TO
THE AREA AS LAKE EFFECT POTENTIAL OFF LAKE HURON LOOKS TO DECREASE
BY SUNRISE. THIS WILL OCCUR AS INVERSION HEIGHTS/CONVECTIVE DEPTHS
DECREASE AS THE HIGH SETTLES IN...AND AS WINDS TURN MORE EASTERLY
DECREASING THE FETCH. THE DAY SHOULD START OUT WITH PLENTY OF
STRATUS LOCKED UNDER THE INVERSION STRETCHING FROM THE THUMB DOWN TO
THE DETROIT AREA. THIS LAYER SHOULD MIX OUT LATER IN THE AFTERNOON
HOWEVER PER LATEST FORECAST SOUNDINGS FROM NAM/GFS. UPSTREAM
OBSERVATIONS DEPICT A VERY DRY AND COLD AIRMASS UNDER THE RIDGE OVER
CANADA AND THE NORTHERN PLAINS (CURRENT DEWPOINTS -20 TO -30
F...WITH MAX TEMPS YESTERDAY BETWEEN -5 AND 15 F). THE AIRMASS
SHOULD MODIFY SOME AS IT CROSSES THE STILL UNFROZEN GREAT
LAKES...AND EXPECTING MAX TEMPS TUESDAY TO REACH THE MID TEENS. IT
IS POSSIBLE IF WE GET ENOUGH SUNSHINE WE COULD OVERACHIEVE...BUT
WILL LEAN THE FORECAST ON THE PESSIMISTIC SIDE GIVEN HIGH POTENTIAL
FOR LAKE STRATUS DURING THE EARLY PART OF THE DAY. MINS OVERNIGHT
WILL BECOME VERY COLD AS EXCELLENT RADIATIONAL COOLING CONDITIONS SET
UP UNDER THE RIDGE CENTER...WITH CLEAR SKIES...LIGHT/CALM
WINDS...FRESH SNOW...AND A VERY DRY AIRMASS. CONTINUED TREND FROM
INHERITED FORECAST WITH MIN TEMPS BELOW MOS GUIDANCE...FROM NEAR
ZERO TO ABOUT 7 BELOW.
WEAK UPPER SHORTWAVE WILL CLIP ACROSS MICHIGAN WEDNESDAY AS IT
PIVOTS AROUND THE UPPER VORTEX CENTERED NORTH OF HUDSON BAY. SURFACE
REFLECTION LOOKS VERY WEAK...AND WILL ONLY MAKE A SMALL RIPPLE IN
THE SURFACE HIGH STILL EXTENDING FROM THE CENTRAL PLAINS UP THROUGH
THE OHIO VALLEY. FRONTAL BOUNDARY WILL WASH OUT AS IT CROSSES
MICHIGAN WITH THIS SYSTEM...BUT FORCING LOOKS TOO WEAK TO OVERCOME
VERY DRY AIRMASS THAT WILL PRECEDE IT. THE RIDGE AXIS WILL GET
PUSHED TO OUR SOUTH AND EAST WEDNESDAY NIGHT AND THURSDAY AS ANOTHER
CLIPPER SYSTEM IS GUIDED ACROSS ONTARIO AROUND THE VORTEX NORTH OF
HUDSON BAY. PRECIPITATION ASSOCIATED WITH THIS SYSTEM LOOKS TO
REMAIN WELL TO OUR NORTH.
BY FRIDAY MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH ANOTHER
RIDGE OF SURFACE HIGH PRESSURE ENCOMPASSING THE GREAT LAKES...BUT
DIFFER WITH THE AMPLIFICATION OF THE UPSTREAM PATTERN OVER THE
WESTERN U.S. AND CANADA. THIS RESULTS IN SOME UNCERTAINTY WITH THE
FORECAST AS WE HEAD INTO THE WEEKEND AND EARLY NEXT WEEK AS MODEL
SOLUTIONS DIFFER GREATLY IN TIMING THE ARRIVAL OF GULF OF ALASKA
ENERGY INTO THE GREAT LAKES. 00Z EURO/GEM CURRENTLY HAVE THE
STRONGEST CONSENSUS AT 144 HOURS...BUT RUN TO RUN CONSISTENCY IN THE
EURO HAS NOT BEEN STRONG. BOTH THESE SOLUTIONS TRACK SURFACE LOW
PRESSURE INTO THE GREAT LAKES ON SATURDAY...BUT WITH ENOUGH OF A
NORTHERLY TRACK TO KEEP MOST PRECIPITATION OUT OF SOUTHEAST MICHIGAN
SO THE FORECAST REMAINS DRY. ADDITIONAL ENERGY LOOKS TO
FOLLOW...POSSIBLY SETTING US UP IN A MORE ACTIVE PATTERN FOR EARLY
NEXT WEEK. TEMPERATURES DO LOOK TO MODERATE FRIDAY AND THROUGH THE
WEEKEND AS ARCTIC CLIPPERS STOP DIVING THROUGH THE AREA. EXPECTING
MAX TEMPS TO WARM BACK CLOSER TO FREEZING.
&&
.MARINE...
GUSTY WINDS WILL DEVELOP OVER LAKE HURON TODAY IN THE WAKE OF AN
EARLY MORNING COLD FRONT. NORTHWESTERLY WIND GUSTS TO 30 KNOTS WILL
BE POSSIBLE OVER ALL BUT INNER SAGINAW BAY. WAVE HEIGHTS WILL ALSO
INCREASE TO AS HIGH AS 7 FEET OVER ICE FREE AREAS THIS AFTERNOON AND
EARLY TONIGHT AS THE FETCH INCREASES. THE COMBINATION OF GUSTY
WINDS...LARGE WAVES...AND COLD TEMPERATURES WILL ALSO CREATE AREAS
OF HEAVY FREEZING SPRAY OVER CENTRAL AND SOUTHERN LAKE
HURON...ESPECIALLY OVER THE OPEN WATERS AND OFF THE TIP OF THE
THUMB. STRONG HIGH PRESSURE BUILDING INTO THE GREAT LAKES TONIGHT
WILL ALLOW FOR A GRADUAL DECREASE IN WINDS AND WAVES TONIGHT. THE
HIGH WILL THEN BRING VERY LIGHT WINDS AS IT SETTLES OVERHEAD ON
TUESDAY.
&&
.AVIATION...ISSUED 1157 PM EST SUN JAN 11 2015
THE AREA OF SNOW COVERING FNT AND PTK AT PRESS TIME WILL SETTLE
SOUTHWARD DURING THE EARLY MORNING AND MERGE WITH A SECOND ROUND OF
SNOW HAVING GREATER INTENSITY FOR THE DTW AREA LATER IN THE NIGHT.
THE EXCEPTION WILL BE MBS ON THE NORTHERN FRINGE OF THE PATTERN.
RESTRICTION WILL BE IFR CLOSER TO 1 MILE. THERE COULD ALSO BE SOME
DROPS INTO LIFR BUT BRIEF ENOUGH TO MONITOR TRENDS BEFORE ADDING
THAT TO THE FORECAST. THE SECOND ROUND OF SNOW WILL LAST THROUGH
ABOUT MID MORNING BEFORE EXITING EASTWARD WITH THE PASSAGE OF THE
ASSOCIATED COLD FRONT. INCREASING NORTH WIND WILL THEN HELP LIFT
CEILING TO VFR DURING THE AFTERNOON INTO MONDAY EVENING.
FOR DTW... ANOTHER ROUND OF SNOW IS EXPECTED TO FILL IN OVER THE
TERMINAL DURING THE EARLY MORNING AND LEAVE ABOUT 1 INCH OF
ADDITIONAL ACCUMULATION BETWEEN 4 AM AND 8 AM. THIS WILL BE A
HEAVIER/WETTER SNOW COMPARED TO RECENT DAYS. A RETURN TO VFR IS
EXPECTED DURING THE AFTERNOON BUT WITH CEILING BELOW 5000 FEET.
//DTW THRESHOLD PROBABILITIES...
* HIGH POTENTIAL FOR CEILING BELOW 5000 FEET THROUGH THE DAY.
* HIGH POTENTIAL FOR SNOW AS PRECIPITATION TYPE.
* LOW POTENTIAL FOR VISIBILITY BELOW 1/2 MILE OR CEILING BELOW 200
FEET.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST
TUESDAY FOR LHZ363-421-441-462>464.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 AM EST TUESDAY FOR
LHZ421-441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...SC
LONG TERM....HLO
MARINE.......HLO
AVIATION.....BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
351 AM CST Mon Jan 12 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 319 AM CST Mon Jan 12 2015
Difficult decision to make this morning regarding the advisory.
Short-range guidance is pretty persistent in redeveloping a band of
light precipitation between I-70 and I-44 in Missouri extending
through the STL Metro area northeast into Illinois between 11Z and
13Z this morning. RAP and NAM are showing some pretty stout
frontogenesis along this corridor during this time period and
various iterations of the WRF model and the HRRR show simulated
light reflectivity in this area. Have therefore increased PoPs to
likely in this area through 14-15Z this morning. Wind has already
swung around to the north along and north of the I-70 corridor and
cooler air is filtering south. The freezing line stretches from
just north of Columbia to Pittsfield at this time, but the north
wind should push it south over the next few hours...and it looks
likely to reach the area in question between 12-13Z Forecast
soundings show little if any ice crystals in the column, but
saturated conditions with temperatures between 0 and -4C there
should be plenty of supercooled water. Ground temperatures are
right at freezing and have had numerous reports of patchy ice on
untreated surfaces last evening and overnight. I`m afraid that
between the cold ground temps and the cold air filtering into the
area the morning rush hour will be slippery. Additionally, rain
overnight may have washed chemicals off the roads which will only
add to the potential for a light glaze. Additionally, MODOT road
condition map is reporting partial coverage across parts of our
southern CWFA, so there`s obviously a little bit of glazing
occurring down there as well. With all this in mind, I cannot in
good conscience let the current advisory expire at 600 AM along and
south of the I-70 corridor across eastern Missouri and Illinois.
Further north/west, the precipitation should be ending pretty
quickly over the next 2-3 hours as drier air filters in behind the
cold front. Will allow the advisory to expire on time from Columbia
to Pittsfield.
Carney
.LONG TERM: (Tonight through Sunday)
Issued at 350 AM CST Mon Jan 12 2015
Weather should be (thankfully) quieter after we get rid of today`s
precip. Another Arctic high will build across the Midwest tonight
and Tuesday. The upper level trof preceding the high doesn`t
amplify the flow enough over the eastern CONUS to allow the ridge
axis to dig much further south than central Illinois or northern
Missouri before the high starts to weaken. Not to say that it won`t
be cold...lows Tuesday morning will range from near zero in
northeast MO to the low and mid teens across the eastern Ozarks.
Northerly flow will continue on Tuesday which will keep temperatures
down in the teens and 20s. A shortwave will ripple overhead
Wednesday which will turn the winds aloft to the west-southwest.
NAM kicks out a little light QPF with the wave, but the GFS is dry.
Low levels should stay very dry, so any precip that does form should
be very light. Should be cold enough for any precip that does form
to be snow, so have added some scattered flurries to the forecast.
Forecast for Thursday through Sunday remains dry at this time, with
an impressive warming trend Friday and Saturday. The lingering high
pressure system will moderate with light west wind on Thursday, and
the GFS and ECMWF have been very consistent in developing warm
southerly flow Friday and continuing into Saturday. GFS is warmer
than than the ECMWF, but have trended a bit toward the warmer
solution and increased temperatures a few degrees over ensemble
guidance. Should be some welcome relief with temperatures well into
the 40s across the area and even around 50 in across parts of
central and eastern Missouri.
Carney
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1021 PM CST Sun Jan 11 2015
Areas of light rain and drizzle continue to move northeastward
through COU and the St Louis metro area this evening. As the surface
temperature falls to the freezing mark it will transition to freezing
drizzle late tonight in COU and towards morning in the St Louis
metro area before ending. The sw-ne band of light snow across
northern portions of MO and IL will drop southeastward through UIN
late tonight along an approaching cold front. The models show this
band of mainly snow weakening before it impacts COU and the St
Louis area. Mainly an IFR cloud ceiling should continue late
tonight into early Monday morning. The light surface wind will
become n-nwly just after 06z tonight in UIN and COU, and around
09z in the St Louis metro area after fropa, then the surface wind
will become relatively strong and gusty Monday morning as the
surface pressure gradient tightens as the strong arctic surface
high over the northern Plains builds southeastward into our area.
The strengthening surface wind will lead to dissipating fog and
improving visibilities. The sky will clear out from northwest to
southeast late Monday morning and afternoon as colder and drier
air advects into the region.
Specifics for KSTL: Periods of light rain and drizzle will
continue late tonight along with fog and cloud ceilings below
1000 feet. There may be a brief period of freezing drizzle towards
morning as the surface temperature falls to the freezing mark. The
ceiling height should rise into the VFR catagory Monday afternoon.
Weak sely surface wind will become n-nwly late tonight, then
strengthen and become gusty Monday morning.
GKS
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 31 14 23 14 / 60 5 5 0
Quincy 19 3 18 8 / 10 0 0 0
Columbia 26 8 22 14 / 20 0 0 5
Jefferson City 30 10 23 13 / 40 0 0 5
Salem 32 18 24 13 / 50 5 0 5
Farmington 33 16 25 14 / 50 5 5 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Callaway
MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-Iron MO-
Jefferson MO-Lincoln MO-Madison MO-Montgomery MO-Osage MO-
Reynolds MO-St. Charles MO-St. Francois MO-St. Louis City
MO-St. Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 AM CST early this morning FOR
Audrain MO-Boone MO-Knox MO-Lewis MO-Marion MO-Moniteau MO-
Monroe MO-Pike MO-Ralls MO-Shelby MO.
IL...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Bond IL-
Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Randolph IL-St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 AM CST early this morning FOR
Adams IL-Brown IL-Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
319 AM CST Mon Jan 12 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 319 AM CST Mon Jan 12 2015
Difficult decision to make this morning regarding the advisory.
Short-range guidance is pretty persistent in redeveloping a band of
light precipitation between I-70 and I-44 in Missouri extending
through the STL Metro area northeast into Illinois between 11Z and
13Z this morning. RAP and NAM are showing some pretty stout
frontogenesis along this corridor during this time period and
various iterations of the WRF model and the HRRR show simulated
light reflectivity in this area. Have therefore increased PoPs to
likely in this area through 14-15Z this morning. Wind has already
swung around to the north along and north of the I-70 corridor and
cooler air is filtering south. The freezing line stretches from
just north of Columbia to Pittsfield at this time, but the north
wind should push it south over the next few hours...and it looks
likely to reach the area in question between 12-13Z Forecast
soundings show little if any ice crystals in the column, but
saturated conditions with temperatures between 0 and -4C there
should be plenty of supercooled water. Ground temperatures are
right at freezing and have had numerous reports of patchy ice on
untreated surfaces last evening and overnight. I`m afraid that
between the cold ground temps and the cold air filtering into the
area the morning rush hour will be slippery. Additionally, rain
overnight may have washed chemicals off the roads which will only
add to the potential for a light glaze. Additionally, MODOT road
condition map is reporting partial coverage across parts of our
southern CWFA, so there`s obviously a little bit of glazing
occurring down there as well. With all this in mind, I cannot in
good conscience let the current advisory expire at 600 AM along and
south of the I-70 corridor across eastern Missouri and Illinois.
Further north/west, the precipitation should be ending pretty
quickly over the next 2-3 hours as drier air filters in behind the
cold front. Will allow the advisory to expire on time from Columbia
to Pittsfield.
Carney
.LONG TERM: (Monday through Next Sunday)
Issued at 230 PM CST Sun Jan 11 2015
Monday will be marked by gusty northerly winds and good cold air
advection as the Arctic front continues its southward surge.
Temperatures should fall through the morning then steady out or
slow their fall in the afternoon. There might be some light
lingering snow or patchy freezing drizzle across parts of east
central/southeast MO and southern IL in the morning. Clouds will
gradually decrease from north to south during the day.
Arctic high pressure settles southward through the upper and mid
MS Valley Monday night into Wedensday bringing another round of
well below average temperatures. The period appears to be dry
however. A shortwave trof will move from the Plains across the
lower and mid MS valley Wednesday-Wednesday night but this is
expected to just bring an increase in clouds with any precipitation
further south.
Heights aloft rise in the wake of this upper trof during the later
part of the week. The flow aloft becomes much flatter compared to
what we have seen in quite some time. Temperatures should respond
accordingly with a nice moderation to above normal by the end of
the week and into next weekend.
Glass
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1021 PM CST Sun Jan 11 2015
Areas of light rain and drizzle continue to move northeastward
through COU and the St Louis metro area this evening. As the surface
temperature falls to the freezing mark it will transition to freezing
drizzle late tonight in COU and towards morning in the St Louis
metro area before ending. The sw-ne band of light snow across
northern portions of MO and IL will drop southeastward through UIN
late tonight along an approaching cold front. The models show this
band of mainly snow weakening before it impacts COU and the St
Louis area. Mainly an IFR cloud ceiling should continue late
tonight into early Monday morning. The light surface wind will
become n-nwly just after 06z tonight in UIN and COU, and around
09z in the St Louis metro area after fropa, then the surface wind
will become relatively strong and gusty Monday morning as the
surface pressure gradient tightens as the strong arctic surface
high over the northern Plains builds southeastward into our area.
The strengthening surface wind will lead to dissipating fog and
improving visibilities. The sky will clear out from northwest to
southeast late Monday morning and afternoon as colder and drier
air advects into the region.
Specifics for KSTL: Periods of light rain and drizzle will
continue late tonight along with fog and cloud ceilings below
1000 feet. There may be a brief period of freezing drizzle towards
morning as the surface temperature falls to the freezing mark. The
ceiling height should rise into the VFR catagory Monday afternoon.
Weak sely surface wind will become n-nwly late tonight, then
strengthen and become gusty Monday morning.
GKS
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 31 14 23 14 / 60 5 5 0
Quincy 19 3 18 8 / 10 0 0 0
Columbia 26 8 22 14 / 20 0 0 5
Jefferson City 30 10 23 13 / 40 0 0 5
Salem 32 18 24 13 / 50 5 0 5
Farmington 33 16 25 14 / 50 5 5 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Callaway
MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-Iron MO-
Jefferson MO-Lincoln MO-Madison MO-Montgomery MO-Osage MO-
Reynolds MO-St. Charles MO-St. Francois MO-St. Louis City
MO-St. Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 AM CST early this morning FOR
Audrain MO-Boone MO-Knox MO-Lewis MO-Marion MO-Moniteau MO-
Monroe MO-Pike MO-Ralls MO-Shelby MO.
IL...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Bond IL-
Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Randolph IL-St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 AM CST early this morning FOR
Adams IL-Brown IL-Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1145 PM PST SUN JAN 11 2015
.SYNOPSIS...RAIN WILL DIMINISH BUT LOW CLOUDS WILL LINGER OVERNIGHT
ACROSS THE MOJAVE DESERT REGION AS A CIRCULATION MOVES FROM SOUTHERN
NEVADA INTO SOUTHERN ARIZONA. ONE FINAL WEATHER DISTURBANCE WILL
PUSH ACROSS THE SOUTHERN GREAT BASIN INTO UTAH AND ARIZONA MONDAY
BRINGING ADDITIONAL CHANCES FOR PRECIPITATION TO THOSE AREAS. DRY
AND PLEASANT WEATHER WILL RETURN TUESDAY THROUGH THE REST OF THE
WORK WEEK.
&&
.UPDATE...QUICK UPDATE TO ADD SOME FOG OVER NORTHWEST SAN BERNARDINO
COUNTY. WE CONTINUE TO MONITOR PATCHY FOG ELSEWHERE. VISIBILITY HAS
GENERALLY REMAINED ABOVE 4 MILES UP TO THIS POINT THIS EVENING.
&&
.PREV UPDATE...
840 PM PST SUN JAN 11 2015
.UPDATE...LIGHT RAIN SHOWERS CONTINUE TO DIMINISH THIS EVENING AND
AND AREAS OF FOG BEGINNING TO DEVELOP IN A FEW AREAS THAT SAW RAIN
TODAY. HAVE UPDATED SKY/POP/WX/QPF GRIDS TO REFLECT THE LATEST
TRENDS AND SHORT RANGE GUIDANCE THROUGH 12Z. OVER THE NEXT FEW HOURS
PRECIPITATION SHOULD CONTINUE TO MOVE EAST INTO ARIZONA. WILL
CONTINUE TO MONITOR THE POSSIBILITY FOR FOG IN THE LAS VEGAS VALLEY.
CLEARING HAS OCCURRED OVER THE NORTHWESTERN THIRD TO HALF OF THE
FORECAST AREA...BUT THERE IS STILL CONSIDERABLE LOW-MID LEVEL
CLOUDINESS WHICH MAY INHIBIT WIDESPREAD FOG IN THE VALLEY.
&&
.AVIATION...FOR MCCARRAN...SHOWERS HAVE ALL BUT ENDED OVER THE LAS
VEGAS VALLEY AND GIGS HAVE BEGUN TO IMPROVE WITH CIGS AROUND 6-9KFT
LIKELY THROUGH MUCH OF THE NIGHT. CONDITIONS WILL CONTINUE TO
IMPROVE AFTER SUNRISE. WINDS WILL REMAIN LIGHT...GENERALLY UNDER 8
KTS THROUGH THE PERIOD. THERE MAY BE SOME AREAS OF FOG AROUND THE
LAS VEGAS VALLEY OVERNIGHT BUT THE CHANCE OF DENSE FOG DEVELOPMENT
AT THE TERMINAL IS VERY REMOTE SINCE SKIES ARE NOT LIKELY TO
CLEAR FULLY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A BROAD AREA OF RAIN CONTINUES TO DISSIPATE THIS
EVENING AS IT MOVES INTO ARIZONA. CLOUD BASES OF TO 5K-9K FEET WILL
LINGER OVERNIGHT AND MOUNTAIN OBSCURATIONS WILL PERSIST. CIGS MAY
LOWER TO AROUND 3K FEET IN/NEAR SHOWER ACTIVITY. AREAS OF FOG WITH
VSBY BELOW 3SM WILL BE POSSIBLE ACROSS THE MOJAVE DESERT REGION
OVERNIGHT. WINDS WILL REMAIN GENERALLY LIGHT THEN INCREASE FROM THE
NORTH OVER THE SOUTHERN GREAT BASIN MONDAY AFTERNOON AS A COLD FRONT
APPROACHES.
&&
.PREV UPDATE...
ISSUED 453 PM PST SUN JAN 11 2015
.UPDATE...AN AREA OF FAIRLY WIDESPREAD LIGHT RAIN WAS MOVING NORTH
ACROSS SOUTHEAST SAN BERNARDINO COUNTY EARLY THIS EVENING WHICH THE
ECMWF DEPICTED NICELY IN THE 00Z-06Z QPF FIELD. I UPDATED TO RAISE
POPS THERE AND TO INCREASE QPF. -HARRISON-
&&
.PREV DISCUSSION...
320 PM PST SUN JAN 11 2015
.SHORT TERM...TONIGHT THROUGH MONDAY.
THE BROAD CLOUD/PRECIPITATION SHIELD THAT HAS BEEN OVER SOUTHERN
NEVADA AND THE WESTERN MOJAVE DESERT MUCH OF THE DAY WAS BEGINNING
TO SHOW SIGNS OF BREAKING UP SLIGHTLY. WE LIKELY SEE FAIRLY
EXTENSIVE PRECIPITATION BEGIN TO TAPER OFF OVER CENTRAL AND EASTERN
CLARK COUNTY LATE THIS AFTERNOON THROUGH EARLY THIS EVENING AS THE
UPPER LEVEL CIRCULATION OVER SOUTHERN CALIFORNIA BEGINS TO PICK UP A
LITTLE SPEED ON ITS WAY TOWARD SOUTHWEST ARIZONA. THE RAIN OVER THE
AREA FROM BARSTOW TO SOUTHERN SAN BERNARDINO SHOULD ALSO BEGIN TO
DIMINISH IN COVERAGE THROUGH EARLY EVENING. THE LATEST HRRR TRENDS
INDICATE ADDITIONAL RAINFALL AMOUNTS OF 0.10-0.20 CAN BE EXPECTED
BEFORE THE BROAD PRECIPITATION BAND FALLS APART. THE LATEST MODELS
INDICATE THAT THE LOW-MID LEVEL CLOUD COVER WILL BE SLOW TO CLEAR
OUT OVERNIGHT AND WE MAY NOT SEE MUCH CLEARING UNTIL AFTER SUNRISE
MONDAY. THE FOG LOW TEMP/DEW POINT SPREADS WILL LIKELY RESULT IN
AREAS OF FOG WHERE SOAKING RAINS HAVE OCCURRED ACROSS SAN
BERNARDINO...CLARK AND MOHAVE COUNTIES THOUGH THE LACK OF
RADIATIONAL COOLING SHOULD NOT PRODUCE MUCH IN THE WAY OF DENSE FOG.
THE SHORT WAVE TROUGH CURRENTLY DROPPING INTO THE PACIFIC NORTHWEST
WILL LEAD TO A DRYER NORTHWEST FLOW OVER MUCH OF THE REGION MONDAY
WITH THE EXCEPTION OF EASTERN NEVADA. THIS WILL LEAD TO A CHANCE OF
PRECIPITATION OVER NORTHERN AND EASTERN LINCOLN COUNTY AND NORTHWEST
ARIZONA MONDAY AFTERNOON INTO MONDAY EVENING. WILL LEAVE A SLIGHT
CHANCE IN FOR THE SPRING MOUNTAINS ALSO DUE TO LINGERING MOISTURE
AND OROGRAPHIC EFFECTS. NORTH WINDS WILL INCREASE MONDAY EVENING AS
A COLD FRONT SWEEPS DOWN THROUGH THE MOJAVE DESERT.
.LONG TERM...TUESDAY THROUGH SUNDAY.
THE BACKSIDE OF LOW PRESSURE HANGS OVER THE AREA TUESDAY LEAVING A
SLIGHT CHANCE OF RAIN/HIGHER ELEVATION SNOW OVER PORTIONS OF THE
EASTERN CWA...PRIMARILY DURING THE EARLY MORNING HOURS. GUSTY NORTH
WINDS ARE EXPECTED AREA WIDE BEHIND A COLD FRONT THAT SWEEPS THROUGH
IN THE MORNING. STRONGER WINDS WILL BE CONFINED TO FAVORED AREAS
SUCH AS THE COLORADO RIVER VALLEY BUT WIND SPEEDS SHOULD REMAIN
BELOW ADVISORY LEVELS.
BRIEF RIDGING IS FORECAST WEDNESDAY BEFORE A WEAK UPPER DISTURBANCE
PASSES THROUGH THE NORTHERN GREAT BASIN AND FLATTENS THE RIDGE ON
THURSDAY. WESTERLY FLOW DOMINATES FRIDAY AND SATURDAY WITH
OCCASIONAL MID AND HIGH CLOUDS PASSING ACROSS THE AREA. THE GFS HAS
AN AGGRESSIVE SOLUTION FOR LATE IN THE WEEKEND AS IT BRINGS A STRONG
TROUGH INTO THE SOUTHWEST. IT HAS SUPPORT FROM ABOUT HALF OF THE GFS
ENSEMBLE MEMBERS WITH THE OTHER HALF MORE IN LINE WITH THE DRY ECMWF
AND GEM. CONTINUING TO HIGHLIGHT A DRY FORECAST THROUGH NEXT WEEKEND
UNTIL A CLEARER MODEL TREND IS ESTABLISHED.
NORTH WINDS LINGER IN THE COLORADO RIVER VALLEY THROUGH THURSDAY BUT
STRONGER WINDS BECOME MORE LOCALIZED BY THURSDAY. TEMPERATURES
THROUGH THE WEEK ARE EXPECTED TO BE NEAR TO SLIGHTLY ABOVE NORMAL
FOR THIS TIME OF YEAR.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT REQUESTED
BUT SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS
THROUGH MONDAY ACCORDING TO STANDARD OPERATING PROCEDURES.
&&
$$
UPDATE/AVIATION...WOLCOTT
SHORT TERM........ADAIR
LONG TERM.........SALMEN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
840 PM PST SUN JAN 11 2015
.SYNOPSIS...RAIN WILL DIMINISH BUT LOW CLOUDS WILL LINGER OVERNIGHT
ACROSS THE MOJAVE DESERT REGION AS A CIRCULATION MOVES FROM SOUTHERN
NEVADA INTO SOUTHERN ARIZONA. ONE FINAL WEATHER DISTURBANCE WILL
PUSH ACROSS THE SOUTHERN GREAT BASIN INTO UTAH AND ARIZONA MONDAY
BRINGING ADDITIONAL CHANCES FOR PRECIPITATION TO THOSE AREAS. DRY
AND PLEASANT WEATHER WILL RETURN TUESDAY THROUGH THE REST OF THE
WORK WEEK.
&&
.UPDATE...LIGHT RAIN SHOWERS CONTINUE TO DIMINISH THIS EVENING AND
AND AREAS OF FOG BEGINNING TO DEVELOP IN A FEW AREAS THAT SAW RAIN
TODAY. HAVE UPDATED SKY/POP/WX/QPF GRIDS TO REFLECT THE LATEST
TRENDS AND SHORT RANGE GUIDANCE THROUGH 12Z. OVER THE NEXT FEW HOURS
PRECIPITATION SHOULD CONTINUE TO MOVE EAST INTO ARIZONA. WILL
CONTINUE TO MONITOR THE POSSIBILITY FOR FOG IN THE LAS VEGAS VALLEY.
CLEARING HAS OCCURRED OVER THE NORTHWESTERN THIRD TO HALF OF THE
FORECAST AREA...BUT THERE IS STILL CONSIDERABLE LOW-MID LEVEL
CLOUDINESS WHICH MAY INHIBIT WIDESPREAD FOG IN THE VALLEY.
&&
.AVIATION...FOR MCCARRAN...SHOWERS HAVE ALL BUT ENDED OVER THE LAS
VEGAS VALLEY AND GIGS HAVE BEGUN TO IMPROVE WITH CIGS AROUND 6-9KFT
LIKELY THROUGH MUCH OF THE NIGHT. CONDITIONS WILL CONTINUE TO
IMPROVE AFTER SUNRISE. WINDS WILL REMAIN LIGHT...GENERALLY UNDER 8
KTS THROUGH THE PERIOD. THERE MAY BE SOME AREAS OF FOG AROUND THE
LAS VEGAS VALLEY OVERNIGHT BUT THE CHANCE OF DENSE FOG DEVELOPMENT
AT THE TERMINAL IS VERY REMOTE SINCE SKIES ARE NOT LIKELY TO
CLEAR FULLY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A BROAD AREA OF RAIN CONTINUES TO DISSIPATE THIS
EVENING AS IT MOVES INTO ARIZONA. CLOUD BASES OF TO 5K-9K FEET WILL
LINGER OVERNIGHT AND MOUNTAIN OBSCURATIONS WILL PERSIST. CIGS MAY
LOWER TO AROUND 3K FEET IN/NEAR SHOWER ACTIVITY. AREAS OF FOG WITH
VSBY BELOW 3SM WILL BE POSSIBLE ACROSS THE MOJAVE DESERT REGION
OVERNIGHT. WINDS WILL REMAIN GENERALLY LIGHT THEN INCREASE FROM THE
NORTH OVER THE SOUTHERN GREAT BASIN MONDAY AFTERNOON AS A COLD FRONT
APPROACHES.
&&
.PREV UPDATE...
ISSUED 453 PM PST SUN JAN 11 2015
.UPDATE...AN AREA OF FAIRLY WIDESPREAD LIGHT RAIN WAS MOVING NORTH
ACROSS SOUTHEAST SAN BERNARDINO COUNTY EARLY THIS EVENING WHICH THE
ECMWF DEPICTED NICELY IN THE 00Z-06Z QPF FIELD. I UPDATED TO RAISE
POPS THERE AND TO INCREASE QPF. -HARRISON-
&&
.PREV DISCUSSION...
320 PM PST SUN JAN 11 2015
.SHORT TERM...TONIGHT THROUGH MONDAY.
THE BROAD CLOUD/PRECIPITATION SHIELD THAT HAS BEEN OVER SOUTHERN
NEVADA AND THE WESTERN MOJAVE DESERT MUCH OF THE DAY WAS BEGINNING
TO SHOW SIGNS OF BREAKING UP SLIGHTLY. WE LIKELY SEE FAIRLY
EXTENSIVE PRECIPITATION BEGIN TO TAPER OFF OVER CENTRAL AND EASTERN
CLARK COUNTY LATE THIS AFTERNOON THROUGH EARLY THIS EVENING AS THE
UPPER LEVEL CIRCULATION OVER SOUTHERN CALIFORNIA BEGINS TO PICK UP A
LITTLE SPEED ON ITS WAY TOWARD SOUTHWEST ARIZONA. THE RAIN OVER THE
AREA FROM BARSTOW TO SOUTHERN SAN BERNARDINO SHOULD ALSO BEGIN TO
DIMINISH IN COVERAGE THROUGH EARLY EVENING. THE LATEST HRRR TRENDS
INDICATE ADDITIONAL RAINFALL AMOUNTS OF 0.10-0.20 CAN BE EXPECTED
BEFORE THE BROAD PRECIPITATION BAND FALLS APART. THE LATEST MODELS
INDICATE THAT THE LOW-MID LEVEL CLOUD COVER WILL BE SLOW TO CLEAR
OUT OVERNIGHT AND WE MAY NOT SEE MUCH CLEARING UNTIL AFTER SUNRISE
MONDAY. THE FOG LOW TEMP/DEW POINT SPREADS WILL LIKELY RESULT IN
AREAS OF FOG WHERE SOAKING RAINS HAVE OCCURRED ACROSS SAN
BERNARDINO...CLARK AND MOHAVE COUNTIES THOUGH THE LACK OF
RADIATIONAL COOLING SHOULD NOT PRODUCE MUCH IN THE WAY OF DENSE FOG.
THE SHORT WAVE TROUGH CURRENTLY DROPPING INTO THE PACIFIC NORTHWEST
WILL LEAD TO A DRYER NORTHWEST FLOW OVER MUCH OF THE REGION MONDAY
WITH THE EXCEPTION OF EASTERN NEVADA. THIS WILL LEAD TO A CHANCE OF
PRECIPITATION OVER NORTHERN AND EASTERN LINCOLN COUNTY AND NORTHWEST
ARIZONA MONDAY AFTERNOON INTO MONDAY EVENING. WILL LEAVE A SLIGHT
CHANCE IN FOR THE SPRING MOUNTAINS ALSO DUE TO LINGERING MOISTURE
AND OROGRAPHIC EFFECTS. NORTH WINDS WILL INCREASE MONDAY EVENING AS
A COLD FRONT SWEEPS DOWN THROUGH THE MOJAVE DESERT.
.LONG TERM...TUESDAY THROUGH SUNDAY.
THE BACKSIDE OF LOW PRESSURE HANGS OVER THE AREA TUESDAY LEAVING A
SLIGHT CHANCE OF RAIN/HIGHER ELEVATION SNOW OVER PORTIONS OF THE
EASTERN CWA...PRIMARILY DURING THE EARLY MORNING HOURS. GUSTY NORTH
WINDS ARE EXPECTED AREA WIDE BEHIND A COLD FRONT THAT SWEEPS THROUGH
IN THE MORNING. STRONGER WINDS WILL BE CONFINED TO FAVORED AREAS
SUCH AS THE COLORADO RIVER VALLEY BUT WIND SPEEDS SHOULD REMAIN
BELOW ADVISORY LEVELS.
BRIEF RIDGING IS FORECAST WEDNESDAY BEFORE A WEAK UPPER DISTURBANCE
PASSES THROUGH THE NORTHERN GREAT BASIN AND FLATTENS THE RIDGE ON
THURSDAY. WESTERLY FLOW DOMINATES FRIDAY AND SATURDAY WITH
OCCASIONAL MID AND HIGH CLOUDS PASSING ACROSS THE AREA. THE GFS HAS
AN AGGRESSIVE SOLUTION FOR LATE IN THE WEEKEND AS IT BRINGS A STRONG
TROUGH INTO THE SOUTHWEST. IT HAS SUPPORT FROM ABOUT HALF OF THE GFS
ENSEMBLE MEMBERS WITH THE OTHER HALF MORE IN LINE WITH THE DRY ECMWF
AND GEM. CONTINUING TO HIGHLIGHT A DRY FORECAST THROUGH NEXT WEEKEND
UNTIL A CLEARER MODEL TREND IS ESTABLISHED.
NORTH WINDS LINGER IN THE COLORADO RIVER VALLEY THROUGH THURSDAY BUT
STRONGER WINDS BECOME MORE LOCALIZED BY THURSDAY. TEMPERATURES
THROUGH THE WEEK ARE EXPECTED TO BE NEAR TO SLIGHTLY ABOVE NORMAL
FOR THIS TIME OF YEAR.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT REQUESTED
BUT SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS
THROUGH MONDAY ACCORDING TO STANDARD OPERATING PROCEDURES.
&&
$$
UPDATE/AVIATION...WOLCOTT
SHORT TERM........ADAIR
LONG TERM.........SALMEN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BUFFALO NY
350 AM EST MON JAN 12 2015
.SYNOPSIS...
A WAVE OF LOW PRESSURE EXTENDING FROM THE GREAT LAKES TO THE OHIO
VALLEY WILL SLIDE TO THE ATLANTIC COASTLINE TODAY WHICH WILL BRING A
WIDESPREAD SNOWFALL TO THE REGION. SNOW WILL TAPER OFF LATE TODAY
WITH A BRIEF PERIOD OF LIGHT LAKE EFFECT SNOW SOUTH OF LAKE ONTARIO
TONIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY WITH FAIR
WEATHER AND MODERATING TEMPERATURES THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A COMPLEX SYSTEM WILL BRING PERIODS OF SNOW TO THE REGION TODAY.
THERE WILL BE SEVERAL RATHER SUBTLE FEATURES WHICH CONTRIBUTE TO
LIFT WITH THIS SYSTEM...WHICH WILL RESULT IN VARIABLE SNOWFALL
RATES. WILL TRY TO BREAK THESE DOWN...BUT IN A GENERAL SENSE
EXPECT A TOTAL OF 2 TO 4 INCHES THROUGH TODAY IN MOST
AREAS...EXCEPT LESSER AMOUNTS OF 1 TO 3 INCHES IN THE GENESEE
VALLEY.
AN INITIAL BAND OF SNOW LIFTED ACROSS THE REGION DURING THE EARLY
MORNING HOURS...WITH THIS MOSTLY DUE TO MID-LEVEL WARM AIR ADVECTION
AND FAVORABLE JET DYNAMICS. THIS AXIS WILL CONTINUE TO LIFT TO THE
NORTHEAST INTO THE EASTERN LAKE ONTARIO REGION THROUGH
DAYBREAK...WITH SNOW TEMPORARILY TAPERING OFF IN ITS WAKE. SNOW WILL
MAINTAIN A BIT BETTER NORTHEAST OF LAKE ERIE WHERE RADAR SHOWS SOME
MODEST LAKE ENHANCEMENT. THE NEXT ROUND WILL COME WITH THE SURFACE
TROUGH AND THE WIND SHIFT ASSOCIATED WITH IT. THIS NORTHWESTERLY
WIND SHIFT WILL ENHANCE SURFACE CONVERGENCE AND BRING ANOTHER ROUND
OF STEADIER SNOWS IN AREAS WEST OF ROCHESTER AROUND DAYBREAK AND MID
TO LATE MORNING EAST OF ROCHESTER. STEADIEST SNOWS WITH THIS
WILL BE ACROSS HIGHER TERRAN EAST OF THE LAKES (CHAUTAUQUA
RIDGE/BOSTON HILLS/TUG HILL) DUE TO OROGRAPHIC LIFT. THIS SAID...WE
ARE STILL LOOKING AT A COUPLE INCHES IN A FOUR HOUR PERIOD. SNOW
WILL TAPER OFF FROM NW-SE THIS AFTERNOON WITH THE EXIT OF THE WEAK
TROUGH OF LOW PRESSURE.
MODEL GUIDANCE APPEARS TO HAVE A GOOD HANDLE ON THIS SYNOPTIC
SYSTEM...WITH THE HRRR PROBABLY DOING THE BEST JOB OF CAPTURING
THESE MULTIPLE FEATURES AND VARIABLE SNOW INTENSITY. NEAR FREEZING
SURFACE TEMPERATURES HAS LEAD TO SNOW RATIOS AROUND 10:1 AND GIVEN
EXPECTED QPF THIS SHOULD KEEP MOST AREAS BELOW ADVISORY
CRITERIA...ESPECIALLY CONSIDERING THE LENGTH OF THE EVENT AND MODEST
SNOWFALL RATES.
A COLD FRONT WILL DROP ACROSS THE REGION LATE THIS AFTERNOON AND
EARLY EVENING. THIS IS LIKELY TO BRING SNOW SHOWERS TO THE EASTERN
LAKE ONTARIO REGION...AND EVENTUALLY SOME LIGHT LAKE EFFECT SNOW
SOUTH OF LAKE ONTARIO TONIGHT. THE COLD AIR WILL BE SHALLOW WITH THE
COLDEST AIR OF AROUND -20C BENEATH 850MB. LOW EQUILIBRIUM LEVELS
BUT AMPLE DENDRITIC SNOW GROWTH SHOULD LEAD TO LIGHT LAKE EFFECT
SNOWS SOUTH OF LAKE ONTARIO WHICH WILL BE AIDED BY UPSLOPING.
ACCUMULATIONS SHOULD BE LIGHT...ONLY AN INCH OR TWO IN MOST
AREAS...BUT SNOW MAY BE PERSISTENT FOR MUCH OF THE NIGHT WITH
DISORGANIZED MULTIPLE BANDS.
THE FRONT WILL USHER IN MUCH COLDER AIR...BUT WITH PERSISTENT CLOUD
COVER EXPECT AREAS SOUTH OF LAKE ONTARIO TO BE WARMER THAN MOST
GUIDANCE. THE COLDEST TEMPERATURES WILL BE EAST OF LAKE ONTARIO
WHERE SKIES SHOULD CLEAR WITHOUT LAKE MOISTURE. THIS WILL ALLOW FOR
BETTER RADIATIONAL COOLING WITH LOWS WELL BELOW ZERO AND WIND CHILLS
APPROACHING 20 BELOW.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
TUESDAY A BROAD AREA OF SURFACE HIGH PRESSURE WILL BE ADVANCING
EASTWARD ACROSS THE GREAT LAKES REGION. AHEAD OF THIS FEATURE...ON A
NORTHERLY FLOW...THERE LIKELY WILL BE ENOUGH LOW LEVEL MOISTURE
WITHIN AN ARCTIC AIRMASS TO GENERATE LAKE EFFECT SNOW SHOWERS OFF
LAKE ONTARIO...WITH ACTIVITY ALSO POSSIBLY BRUSHING THE EASTERN LAKE
ERIE SHORELINE OF THE SOUTHERN TIER ON A NORTH-NORTHEASTERLY WIND.
DUE TO THE SHALLOWNESS OF THE MOISTURE...AND ONLY FAIR LAKE
INSTABILITY PARAMETERS...SNOWFALL TUESDAY MORNING WILL ONLY BE AN
ADDITIONAL HALF INCH NEAR THE SOUTHERN LAKE ONTARIO SHORELINE.
OTHERWISE A COLD START TO THE DAY AS -14C 850 HPA AIR FLOWS OVER THE
REGION. WITHIN THE DRY...ARCTIC AIRMASS SKIES WILL BECOME MOSTLY
SUNNY BY AFTERNOON...AFTER WANING LAKE EFFECT ACTIVITY DIMINISHING.
HIGHS WILL STRUGGLE TO REACH DOUBLE DIGITS AS THE LIGHT NORTHERLY
FLOW REPLENISHES THE COLD SURFACE AIR.
CLEAR AND COLD TUESDAY NIGHT AS SURFACE HIGH PRESSURE DRAWS CLOSER.
LIGHT WINDS AND GOOD RADIATIONAL COOLING WILL ALLOW MOST AREAS TO
DROP TO ZERO...AND INTO THE NEGATIVE TEENS/-20F ACROSS THE NORTH
COUNTRY WHERE A DEEP AND YET FRESH SNOWPACK ENHANCES THE RADIATIONAL
COOLING. BECAUSE OF THE LIGHT WINDS...WIND CHILL HEADLINES ARE NOT
LIKELY.
SUNNY AND DRY WEDNESDAY WITH THE SURFACE HIGH PRESSURE OVERHEAD.
LIGHT SOUTHERLY WINDS AGAIN WILL ALLOW FOR OVERNIGHT LOWS TO QUICKLY
DROP...INTO THE SINGLE DIGITS SOUTH OF LAKE ONTARIO...AND NEAR ZERO
EAST OF LAKE ONTARIO.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A QUIET WEATHER PATTERN IS EXPECTED TO CLOSE OUT THE WORK WEEK.
TEMPERATURES WILL MODERATE TO NEAR NORMAL VALUES BY THURSDAY AS
SURFACE HIGH PRESSURE SLIDES EASTWARD AND BRINGS LIGHT SOUTHERLY
WINDS BACK ACROSS THE AREA. A COLD FRONT LOOKS TO PASS THE AREA ON
FRIDAY...HOWEVER THE BULK OF THE MOISTURE WILL REMAIN WELL TO OUR
NORTH...BOTH LIMITING THE SYNOPTIC SNOW POSSIBILITY FRIDAY...AND
LAKE EFFECT ACTIVITY INTO THE START OF THE WEEKEND. LOOKING TOWARD
NEXT WEEK...GLOBAL MODELS ARE IN FAIR AGREEMENT THAT THERE WONT BE
MUCH COLD AIR AROUND. OVERALL TEMPERATURES LOOKS AVERAGE TO SLIGHTLY
ABOVE AVERAGE...WITH A FEW CHANCES FOR SOME SOUTHERN STREAM WAVES TO
BRING SOME LIGHT PRECIPITATION AT TIMES.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
IT IS A VERY DIFFICULT FORECAST THROUGH 18Z TODAY...WITH NUMEROUS
FEATURES TO CONTEND WITH. EXPECT CONDITIONS TO VARY BETWEEN IFR/MVFR
IN BETWEEN ROUNDS OF STEADIER SNOWS. IN GENERAL...THE FIRST WAVE
WILL LIFT NORTHEAST OF THE AREA SHORTLY AFTER 09Z...BUT ANOTHER
ROUND WILL FOLLOW BETWEEN 12Z AND 18Z WITH A WEAK TROUGH OF LOW
PRESSURE AND THE ASSOCIATED WIND SHIFT. THERE WILL ALSO BE MODEST
LAKE ENHANCEMENT WHICH WILL LOCALLY LOWER VSBY AT BUF/IAG/ART. IN
GENERAL VSBY SHOULD AVERAGE BETWEEN 1SM AND 3SM DURING THIS
TIME...WITH BRIEFLY LOWER CONDITIONS TO 1/2SM POSSIBLE WITH THE WIND
SHIFT.
EXPECT IMPROVING CONDITIONS THIS AFTERNOON AS THIS WAVE EXITS
EAST...BUT THIS WILL PROBABLY BE SHORT LIVED. A COLD FRONT WILL DROP
SOUTHWARD ACROSS THE REGION LATE THIS AFTERNOON AND EARLY EVENING.
THIS WILL BRING A LOW INVERSION WITH COLDER TEMPERATURES LIKELY TO
TRAP LAKE MOISTURE BENEATH IT. THERE ALSO WILL BE AMPLE FLOW TO
GENERATE SOME LIGHT SNOW SHOWERS SOUTH OF LAKE ONTARIO. THIS IS
LIKELY TO RESULT IN IFR CONDITIONS AT BUF/IAG/ROC...AND POSSIBLY JHW
FOR MOST OF TONIGHT.
OUTLOOK...
TUESDAY THROUGH FRIDAY...MAINLY VFR.
&&
.MARINE...
A COLD FRONT WILL DROP SOUTH ACROSS THE LOWER LAKES LATE THIS
AFTERNOON...FOLLOWED BY A BRIEF SURGE OF MODERATE NORTHWESTERLY TO
NORTHERLY WINDS WHICH WILL PRODUCE SMALL CRAFT ADVISORY LEVEL
CONDITIONS ON BOTH LAKES MONDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
INTO THE GREAT LAKES BY TUESDAY MORNING ALONG WITH DIMINISHING WINDS
AND WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 4 AM EST
TUESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 4 AM
EST TUESDAY FOR LOZ030.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
TUESDAY FOR LOZ042>045.
&&
$$
SYNOPSIS...HITCHCOCK/JJR
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1241 AM EST MON JAN 12 2015
.SYNOPSIS...
A COASTAL FRONT WILL MOVE TOWARD THE COAST LATE TONIGHT WITH
SUBTROPICAL AIR SPREADING ONTO THE BEACHES. MUCH COLDER CONDITIONS
WILL PERSIST INLAND AS A WEDGE OF HIGH PRESSURE REMAINS ACROSS THE
INTERIOR CAROLINAS. A WEDGE OF HIGH PRESSURE WILL BUILD DOWN INTO
THE CAROLINAS MONDAY THROUGH WEDNESDAY...PUSHING THE BOUNDARY BACK
OFFSHORE AND CONTINUING UNSETTLED CONDITIONS. A LARGE AREA OF LOW
PRESSURE WILL MOVE WELL OFF THE SOUTHEAST COAST THURSDAY INTO FRIDAY
BEFORE HIGH PRESSURE RETURNS FOR THE WEEKEND WITH A WARMING TREND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 12:35 AM MONDAY...THE COASTAL FRONT APPEARS TO HAVE MOVED
VERY LITTLE OVER THE PAST FEW HOURS. WE HAVE BEEN CLOSELY
MONITORING TEMPERATURE AND WIND DIRECTION TRENDS AT THE BALD HEAD
ISLAND MESONET SITE FOR ANY SIGN THE FRONT IS APPROACHING. THEIR
CONDITIONS ARE ALMOST UNCHANGED FROM THOSE BACK AT 630 PM. THIS
TREND APPEARS TO BE ECHOED BY THE NEW 00Z NAM WHICH HAS DELAYED
THE COASTAL FRONT`S ARRIVAL BY 3-4 HOURS...PLACING IT LATE TONIGHT
FOR SE NORTH CAROLINA AND CLOSE TO 12Z/7 AM EST FOR THE GRAND
STRAND.
THE OTHER ITEM OF INTEREST IS SOME INTENSELY DRY AIR ACROSS THE
INLAND CAROLINAS. DEWPOINTS REMAIN IN THE 20S WITH SOME TEENS WEST
OF I-95 IN THE DARLINGTON-BENNETTSVILLE REGION. RADAR ECHOES ARE
BEGINNING TO INCREASE ACROSS CENTRAL SOUTH CAROLINA MEANING WE ARE
PROBABLY ONLY A COUPLE HOURS AWAY FROM SHOWERS DEVELOPING ACROSS THE
PEE DEE REGION. AIR TEMPERATURES REMAIN IN THE MID TO UPPER 40S...
AND WITH THESE LOW DEWPOINTS THE WET BULB TEMPERATURE IS AS LOW AS
35-36 DEGREES WEST OF I-95. WITH DEWPOINTS NOT ANTICIPATED TO FALL
ANY FURTHER I THINK WE CAN SAFELY RULE OUT ANY FREEZING RAIN
POTENTIAL AT LEAST IN OUR FORECAST AREA.
PREVIOUS DISCUSSION FROM 645 PM FOLLOWS...
THE COASTAL FRONT APPEARS TO BE LOCATED ABOUT 20 MILES EAST OF CAPE
FEAR BASED ON WIND DIRECTIONS AT BUOYS 41037 AND 41013
(SOUTHEASTERLY) VERSUS WIND DIRECTIONS AT THE BEACHES (NORTHERLY).
ALMOST ALL MODEL GUIDANCE SHOWS THE FRONT MOVING WESTWARD AND
ONSHORE AFTER MIDNIGHT...WITH TEMPERATURES RISING INTO THE UPPER 50S
TO LOWER 60S ACROSS THE CAPE FEAR REGION AND THE SC BEACHES LATE
TONIGHT. ON THE WEST SIDE OF THE COASTAL FRONT EVAPORATIONAL COOLING
IN RATHER DRY AIR SHOULD LOCK IN THE COLD TEMPERATURES WITH READINGS
IN THE UPPER 30S AND 40S EXPECTED. THE THERMAL BOUNDARY AT THE
SURFACE WILL BE INTENSE AND VERY DIFFICULT TO FORECAST ACCURATELY.
DESPITE THE CHALLENGING NATURE OF THIS FORECAST THERE WERE FEW
CHANGES NEEDED TO THE FORECAST. SHOWERS SHOULD STILL DEVELOP ACROSS
SOUTH CAROLINA AND INTERIOR NORTH CAROLINA LATE THIS EVENING...
FINALLY REACHING THE CAPE FEAR AREA LATE TONIGHT. FORECAST POPS
REMAIN AT 100 PERCENT AREA-WIDE. THE LATEST HRRR MODEL RUN
EXPLICITLY DEPICTS THE CONVECTIVE NATURE OF THE RAIN EVEN INLAND.
THIS MAKES SENSE AS SMALL ELEVATED INSTABILITY SHOULD DEVELOP DUE TO
WARM ADVECTION ON SOUTH WINDS JUST ABOVE THE SURFACE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...CHALLENGING FORECAST FOR MON AS A COASTAL
TROUGH ATTEMPTS TO PUSH ONSHORE AND A COOL WEDGE OF HIGH PRESSURE
BEGINS TO ERODE INLAND. AS IS COMMON WITH THESE SETUPS...SUBTLE
CHANGES TO THE POSITIONING/LOCATION OF THE COASTAL FRONT WILL HAVE
BIG IMPLICATIONS IN TERMS OF THE TEMP FORECAST FOR TOMORROW. IT DOES
APPEAR THE COASTAL FRONT WILL PUSH THROUGH AT LEAST OUR COASTAL
ZONES...BRINGING WARMER S-SW FLOW TO THESE LOCATIONS WHILE THE
INLAND ZONES REMAIN UNDER THE WANING INFLUENCE OF COOLER HIGH
PRESSURE. THE END RESULT IS A SHARP GRADIENT FOR HIGH TEMPS ON
MON...RANGING FROM LOW TO MID 60S AT THE BEACHES TO LOW TO MID 50S
WEST OF I-95.
HIGHER CONFIDENCE REGARDING THE PCPN FORECAST AS LKLY/CATEGORICAL
POPS WILL PREVAIL THROUGH THE MORNING/AFTN HOURS. MOIST ISENTROPIC
ASCENT COMBINED WITH AN UPPER DISTURBANCE LIFTING OUT OF THE GULF
WILL GENERATE STRATIFORM RAIN ACROSS THE REGION. MEANWHILE...SHOWERS
WILL DEVELOP IN THE WARMER AIR MASS BEHIND THE COASTAL FRONT. SPC
MENTIONS THE POSSIBILITY OF A FEW ISOLATED TSTMS ALONG THE COAST...
BUT WILL HOLD OFF ON MENTIONING THUNDER OVER OUR LAND ZONES ATTM.
EMBEDDED CONVECTIVE ELEMENTS COULD PRODUCE HEAVIER RAINFALL NEAR AND
BEHIND THE COASTAL TROUGH. AREA WIDE QPF FROM 7AM-7PM TOMORROW
FALLS IN THE 0.5-0.75 IN RANGE.
RAIN CHANCES DIMINISH INTO EARLY TUE AS LOW PRESSURE ALONG THE
TROUGH LIFTS UP THE ATLANTIC COAST. THEN COLD HIGH PRESSURE ONCE
AGAIN WEDGES DOWN THROUGH THE CAROLINAS...USHERING IN MUCH COOLER
AIR FOR TUE. HIGH TEMPS WILL BE IN THE MID/UPPER 40S INLAND TO LOWER
50S AT THE COAST. THESE HIGHS WILL BE REALIZED EARLY IN THE MORNING
AS TEMPS ARE EXPECTED TO FALL DURING THE DAY WITH CONTINUED COLD AIR
ADVECTION. MODEST OVERRUNNING MAY RESULT IN MORE -RA DURING THE
DAY...BUT POPS RAMP UP AGAIN OVERNIGHT AS ANOTHER SHORTWAVE FURTHER
ENHANCES LIFT OVER THE CAROLINAS. AFTER 09Z WED...A BRIEF WINDOW
EMERGES FOR -FZRA/FZDZ OVER OUR FAR NORTHWEST ZONES WEST OF I-95.
THE THREAT APPEARS MARGINAL AT THIS TIME SINCE THE COLD AIR WILL BE
CHASING THE MOISTURE...BUT THE POTENTIAL IS THERE IF SFC TEMPS DROP
BELOW FREEZING WITH ENOUGH MOISTURE STILL IN PLACE TO SUPPORT PCPN.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...COMPLEX AND ACTIVE PATTERN WILL MAINTAIN
PERIODS OF UNSETTLED WEATHER DURING THE LATTER HALF OF THE WEEK
BEFORE IMPROVEMENT DEVELOPS FOR THE UPCOMING WKND.
PERIOD BEGINS INTERESTING AS A WEAK SHORTWAVE WILL BE MOVING
OVERHEAD WEDNESDAY MORNING. AS THIS OCCURS...MID-LEVEL FLOW WILL
BACK INCREASINGLY TO THE SW...HELPING TO ERODE A COLD SURFACE WEDGE.
ALTHOUGH THE COLUMN WILL BE DRYING BY WEDNESDAY MORNING...RESIDUAL
LOW-LEVEL MOISTURE WILL MANIFEST AS OVERCAST LOW CLOUD COVER AND
PERIODS OF DRIZZLE ACROSS MUCH OF THE AREA. THE BIGGEST CONCERN IS
WHETHER LIGHT FREEZING RAIN/DRIZZLE WILL OCCUR FOR A FEW HOURS WELL
INLAND WEDNESDAY MORNING. FORECAST PROFILES SUGGEST A STRONG
INVERSION...COMMON IN A WEDGE SETUP...WITH SURFACE TEMPS IN THE NW
ZONES RIGHT AROUND 31/32 DEGREES. SURFACE WET BULB TEMPS ARE
FORECAST TO BE BELOW 32 ROUGHLY NW OF I-95...BUT THERE IS NO
SATURATION WITHIN THE DENDRITIC GROWTH ZONE (ALTHOUGH WITH A WARM
NOSE OF 6-8C THIS IS SORT OF IRRELEVANT IN THIS CASE).
THUS...-FZRA/FZDZ IS THE ONLY POSSIBLE P-TYPE OTHER THAN R-. LOCAL
TOP DOWN METHODOLOGY GIVES A SMALL STRIP OF R-/-FZRA FROM ABOUT TAR
HEEL...SW TO HARTSVILLE...AND WILL KEEP THIS IN OFFICIAL FORECAST
BUT WITH ONLY A FEW HUNDREDTHS OF AN INCH OF QPF...AT WORST.
WHILE QPF WILL BE MINIMAL...EVEN A BIT OF -FZRA/-FZDZ WOULD CAUSE
SOME IMPACTS WEDNESDAY MORNING SO THIS WILL NEED TO BE MONITORED
CLOSELY. FORTUNATELY...TEMPS BEFORE ANY FREEZING PRECIP WILL BE WARM
AND ACCOMPANIED BY RAIN...SO ROAD IMPACTS ARE EXPECTED TO BE MINIMAL
AT WORST. TEMPS WILL WARM TO ABOVE FREEZING BY LATE MORNING
EVERYWHERE...BUT DRIZZLE AND LOW CLOUDS WILL REMAIN THROUGH THE DAY
WILL TEMPS STRUGGLING ONLY INTO THE UPPER 30S/LOW 40S.
A MORE SIGNIFICANT STORM SYSTEM WILL THEN DEVELOP OFF THE SOUTHEAST
COAST THURSDAY NIGHT INTO FRIDAY. A CLOSED LOW ACROSS THE DESERT SW
WILL EJECT EAST ACROSS THE SOUTHERN TIER...WHILE A NORTHERN STREAM
SHORTWAVE WILL DIVE INTO THE MIDDLE OF THE COUNTRY. GUIDANCE SHOWS
DIFFERENT LEVELS OF PHASING NEAR THE GULF OF MEXICO WITH THESE
FEATURES...BUT EITHER WAY A LARGE LOW PRESSURE SYSTEM IS EXPECTED TO
MOVE UP THE COAST OVERNIGHT THURSDAY INTO FRIDAY. TEMPS ARE FORECAST
TO BE COLD...BUT ABOVE FREEZING...AND AS ISENTROPIC LIFT INCREASES
LATE THURSDAY INTO FRIDAY...A COLD RAIN IS EXPECTED AREA-WIDE. THE
RAIN COULD BE HEAVY...ESPECIALLY NEAR THE COAST...DEPENDING ON HOW
FAR OFFSHORE THE LOW TRACKS...AND CURRENT WPC QPF SHOWS UP TO
ONE-HALF INCH NEAR THE COAST.
AS THE LOW PULLS AWAY LATE FRIDAY...COOL HIGH PRESSURE WILL BUILD
EAST MAINTAINING BELOW NORMAL TEMPERATURES INTO THE WKND.
HOWEVER...THIS HIGH WILL PUSH OFF THE MID-ATLANTIC COAST SATURDAY AS
THE FLOW BECOMES MORE PROGRESSIVE...AND MOST OF THE WKND WILL
FEATURE ABUNDANT SUNSHINE WITH ABOVE NORMAL TEMPERATURES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...DETERIORATING CONDITIONS ARE EXPECTED OVER THE NEXT FEW
HOURS AS RAIN BECOMES WIDESPREAD. THE STEADY PRECIP WILL QUICKLY
LOWER CEILINGS TO MVFR...BECOMING IFR AN HOUR OR TWO LATER.
VISIBILITIES AS WELL WILL LIKELY LOWER TO IFR TOWARD MORNING. THE
WEDGE WILL LIKELY STAY IN AT THE INLAND TERMINALS FOR MOST OF THE
DAY WITH NORTHEAST WINDS...HOWEVER LOOK FOR THE WARM FRONT TO COME
ONSHORE AT THE COASTAL TERMINALS JUST AFTER DAYBREAK WITH A PRETTY
SHARP WIND SHIFT TO THE SOUTH. RAIN COULD BE HEAVY AT TIMES WITH AN
EMBEDDED SHOWER OR TWO. MOST OF THE DEEP MOISTURE MOVES OUT BY
00Z...HOWEVER LOW LEVEL MOISTURE WILL REMAIN WITH POSSIBLE LIFR
VISIBILITIES.
EXTENDED OUTLOOK...RAIN AND MVFR/IFR CONDITIONS WILL PREVAIL
POSSIBLY THROUGH WED AS A COOL WEDGE REMAINS LOCKED IN PLACE OVER
THE CAROLINAS. RAIN/MVFR ON THU. VFR FRI AND SAT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:35 AM MONDAY...NO MOVEMENT HAS BEEN OBSERVED WITH THE
COASTAL FRONT OVER THE PAST FEW HOURS. RECENT MODEL TRENDS
INDICATE THE BOUNDARY SHOULD STILL MOVE ONSHORE...BUT DELAYED BY
ABOUT 3-4 HOURS FROM PREVIOUS THINKING. NE WINDS WILL VEER E-SE
WITH THE PASSAGE OF THE FRONT...ALSO ACCOMPANIED BY A SUDDEN
INCREASE IN TEMPERATURES AND HUMIDITY. SHOWER ACTIVITY HAS BEEN A
LITTLE SLOWER TO DEVELOP BUT RADAR TRENDS INDICATE SHOWERS ARE
EXPANDING ACROSS CENTRAL SOUTH CAROLINA. PREVIOUS DISCUSSION FROM
645 PM FOLLOWS...
THE COASTAL FRONT APPEARS TO BE LOCATED ABOUT 20 MILES EAST OF CAPE
FEAR...40 MILES EAST OF MYRTLE BEACH...AND 30 MILES EAST OF
GEORGETOWN. THIS IS BASED ON WIND DIRECTIONS AT BUOYS AND BEACH
LOCATIONS REPORTED WITHIN THE PAST HALF HOUR. VIRTUALLY ALL MODEL
GUIDANCE INDICATES THIS BOUNDARY SHOULD PUSH WESTWARD
TONIGHT...REACHING THE BEACHES A FEW HOURS AFTER MIDNIGHT WITH
SOUTHEASTERLY WINDS DEVELOPING. THIS WILL BRING IN A WARMER AND MUCH
MORE HUMID AIRMASS FROM THE GULF STREAM WITH AIR TEMPERATURES AND
DEWPOINTS RISING SIGNIFICANTLY FROM THEIR CURRENT LEVELS. SHOWERS
SHOULD INCREASE IN COVERAGE SOUTH OF CAPE FEAR LATE THIS
EVENING...SPREADING NORTH OF CAPE FEAR AFTER MIDNIGHT.
WITH SEA SURFACE TEMPERATURES IN THE 50S AND EVEN SOME UPPER 40S
ALONG THE SC COAST...SOME SEA FOG MAY DEVELOP AFTER MIDNIGHT AS
HUMID AIR FROM THE GULF STREAM ARRIVES.
SEAS CURRENTLY RANGE FROM 2-4 FEET AND SHOULD BUILD TOWARD 6 FEET
ACROSS OPEN WATERS LATE TONIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...SMALL CRAFT ADVISORY WILL BE IN EFFECT AT THE
START OF THE PERIOD. SEAS WILL BE RUNNING 5-7 FT WITH S-SW WINDS
20-25 KT IN RESPONSE TO A COASTAL TROUGH/FRONT OVER THE WATERS.
EXPECT SHOWERS/ISO TSTMS THROUGH THE DAY IN ASSOCIATION WITH THIS
FEATURE. THE WINDS WILL VEER AND RELAX A BIT AFTER 18Z...BECOMING
W-NW 10-15 KT...AS THE WAVE OF LOW PRESSURE LIFTS NORTHWARD. THIS
WILL HELP BRING AN END TO SCA CONDITIONS BY MONDAY EVENING AS SEAS
SUBSIDE TO 3-5 FT. COLD HIGH PRESSURE WEDGING DOWN ACROSS THE
CAROLINAS TUE WILL BE ACCOMPANIED BY A NORTHEASTERLY SURGE AS WIND
SPEEDS INCREASE TO 15-25 KT. SEAS WILL ACCORDINGLY BUILD TO 4-6 FT
AFTER 18Z TUE...5-7 FT OVER THE OUTER WATERS OF AMZ250/252...LIKELY
REQUIRING ANOTHER SCA TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...GUSTY NORTH WINDS ON THE PERIPHERY OF A WEDGE
OF HIGH PRESSURE WILL EASE THROUGH WEDNESDAY...FALLING FROM 20-25
KTS EARLY TO 10-15 KTS WEDNESDAY NIGHT. SEAS WILL DROP AS
WELL...FROM 4-7 FT FIRST THING WEDNESDAY...TO 2-4 FT BY THURSDAY
MORNING...AND A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED THE FIRST
HALF OF WEDNESDAY. ALTHOUGH THE WEDGE WILL BREAK DOWN THURSDAY...A
LARGE AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OFF THE SOUTHEAST
COAST AND RACE NORTHEAST INTO FRIDAY...MAINTAINING NORTHERLY WINDS.
THE PLACEMENT OF THIS LOW PRESSURE WILL HAVE SIGNIFICANT IMPACT ON
LOCAL WINDS...BUT EXPECT A STEADY INCREASE IN SPEEDS TO 20 KTS OR
MORE OVERNIGHT THURSDAY INTO FRIDAY BEFORE FALLING AGAIN LATE. SEAS
WILL BUILD ON THE STRONG WINDS BACK TO 3-5 FT...WITH UP TO 6 FT
POSSIBLE...AND ANOTHER SCA MAY BE NEEDED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR AMZ250-
252-254-256.
&&
$$
SYNOPSIS...JDW
NEAR TERM...REK/RJD/TRA
SHORT TERM...BJR
LONG TERM...JDW
AVIATION...DL
MARINE...REK/RJD/TRA/JDW/BJR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
101 AM EST MON JAN 12 2015
.SYNOPSIS...
LOW PRESSURE SYSTEM AND MOSTLY RAIN TONIGHT. A COLD FRONT MOVES
THROUGH ON MONDAY. WEAK WAVE OF LOW PRESSURE SOUTH POSSIBLE MONDAY
NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
100 AM UPDATE...ALLOWED SOUTHERN PORTIONS OF FREEZING RAIN
ADVISORY TO EXPIRE AS TEMPS ARE 34 AN HIGHER NOW. EXTENDED
NORTHERN PORTIONS TO MATCH UP WITH 6 AM EXPIRATION TIME IN SE OHIO
COUNTIES AS TEMPS ARE STILL IN THAT 32-33 RANGE.
PREVIOUS DISCUSSION...
630 PM UPDATE. PRECIP MOVED IN FASTER AND MADE ADJUSTMENTS IN POPS
ACCORDINGLY. ALSO INCLUDED SOME VERY LIGHT ICE PELLETS AND OR
FREEZING RAIN FOR MOST AREAS FOR 2-3 HOURS THIS EVENING...OUTSIDE OF
ADVISORY AREAS AND UP UNTIL FREEZING RAIN ADVISORIES BEGIN FOR THE
OTHER AREAS. ALL IN ALL...SOME SLIPPERY SPOTS POSSIBLE THIS EVENING
AND ADDRESSED IN SPECIAL WEATHER STATEMENT ISSUED EARLIER.
OTHERWISE...OUTSIDE OF ADVISORY AREAS PRECIP SHOULD BE ALL RAIN BY
03Z AS TEMPS BEGIN TO INCH UP AGAIN.
PREVIOUS DISCUSSION...
REMAIN CONCERNED WITH THE MODEL TRENDS OF GETTING WARMER FOR
TONIGHT IN SOUTHEAST OHIO AND EXTREME NORTHWESTERN WV. MET/MAV AND
LAV GUIDANCE ARE WARMER THAN THE FORECAST...BUT THE HRRR STILL SHOWS
WET BULBING CAUSING ISSUES. WITH SUCH LOW DEW POINTS
CURRENTLY...FROZEN GROUND...AND ADVISORIES ALREADY IN PLACE...WILL
HOLD TIGHT...BUT EVENING SHIFT WILL NEED TO MONITOR THIS CLOSELY.
HRRR AND NAM SOUNDINGS SHOWING POTENTIAL PROBLEMS IN THE SOUTHEAST
UPSLOPE AREAS OF THE NORTHERN MOUNTAINS AS WELL. IN THIS REGION
HOWEVER...LAV GUIDANCE IS SHOWING TEMPERATURE HOOVERING RIGHT AROUND
FREEZING AT LWB...WHICH IS NOT NORMALLY THE COLDEST SPOT. WITH
GROUND FROZEN...THINK THAT POCKETS OF FREEZING RAIN A GOOD BET. WILL
ISSUE A FREEZING RAIN ADVISORY OVERNIGHT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
WITH THE FRONTAL BOUNDARY OFF TO THE SOUTHEAST...WILL BE INFLUENCED
BY A DEVELOPING INVERTED SURFACE TROUGH SETTING UP ALONG THE
MOUNTAINS IN COMBINATION WITH A WEAK MID AND UPPER LEVEL WAVE. THE
RESULT IN THE GRIDS IS NOT TOO MUCH OF A CHANGE IN TERMS OF THE
POPS...KEEPING THE LOW END POPS OVER THE MOUNTAINS BEFORE ENDING
WEDNESDAY. LARGELY BASED THE POPS ON LOW-MID LEVEL LAYER
FRONTOGENESIS WHICH IS ON THE WEAKER SIDE...BUT STILL PRESENT WHEN
LOOKING AT THE NAM.
AN OVERRUNNING SITUATION WILL BE PRESENT WITH THE MOISTURE OVER THE
MOUNTAINS AS THE TROUGH SETS UP AND WILL KEEP IT SIMPLE IN THE
WEATHER GRIDS BY USING THE WARM LAYER ALOFT FROM THE NAM. THIS
CREATES BRIEF SLEET/FREEZING RAIN POTENTIAL BEFORE THE COLD AIR
ADVECTION TAKES HOLD AND TRANSITIONS THE WEATHER TYPE TO ALL SNOW
INTO TUESDAY. ALL THE WHILE...POPS WILL BE LOWERING.
NOT SEEING MUCH OF A TEMPERATURE RECOVERY TUESDAY FROM MONDAY NIGHT
GIVEN THE CLOUD COVER AND WEAK COLD AIR ADVECTION WHICH WILL BE HELD
IN CHECK BY THE MOISTURE PUSH FROM THE AFOREMENTIONED SURFACE TROUGH
FROM THE SOUTH. KEEPING IT COLD ENOUGH IN THE FORECAST FOR OFF AND
ON LIGHT SNOW OVER THE MOUNTAINS AFTER THE FULL PRECIPITATION TYPE
TRANSITION TUESDAY AND TUESDAY NIGHT...WITH SOME LOCATIONS CLIMBING
ABOVE FREEZING WEDNESDAY AS 850MB TEMPERATURES MODIFY SLIGHTLY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLDER AIR SWEEPS IN FOR A SEASONABLY COOL EXTENDED. EXPECTING A
MAINLY DRY EXTENDED IS IN THE CARDS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MIX OF VFR AND MVFR AS AREA OF RAIN MOVES NORTH. SOME SLEET STILL
POSSIBLE ACROSS NORTHERN CWA...AND SURFACE TEMPS NEAR OR JUST
BELOW FREEZING SO PATCHES OF FREEZING RAIN ALSO POSSIBLE. TEMPS
SHOULD WARM ABOVE FREEZING THROUGH THE REMAINDER OF THE
NIGHT...WITH PRECIP BECOMING RAIN AT TAF SITES. CEILINGS WILL DROP
THROUGH THE DAY AS A COLD FRONT MOVES THROUGH. HAVE IFR IN RAIN
AND LOW CLOUDS WITH THE FRONT...WITH LOWER CIGS LINGERING BEHIND
THE FRONT AS WELL. AS COLD AIR WORKS IN ALOFT...RAIN WILL CHANGE
TO SNOW OR SLEET BEHIND THE FRONT. LIGHT AND VARIABLE WINDS AHEAD
OF THE FRONT FOR THE LOWLANDS WITH MORE CONSISTENT SOUTHERLY FLOW
IN THE MOUNTAINS. WINDS WILL BECOME NW BEHIND THE FRONT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING OF LOWERING CEILINGS AND VISIBILITY
RESTRICTIONS COULD VARY.
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 MON 01/12/15
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H H H H H H H H M M H
HTS CONSISTENCY H H H H H H H H M M M H
BKW CONSISTENCY M M M M M M M M M H M H
EKN CONSISTENCY H H H M H H M H H H L L
PKB CONSISTENCY M M M H H H L L L M M H
CKB CONSISTENCY M M M H H H M L L L L L
AFTER 06Z TUESDAY...
IFR POSSIBLE INTO TUESDAY...ESPECIALLY ACROSS THE MOUNTAINOUS COUNTIES.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
WVZ007>011-016>020-028>032-038>040.
FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR WVZ046-
047.
OH...FREEZING RAIN ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
OHZ075-076-083>086.
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR OHZ066-
067.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...RPY/MZ
SHORT TERM...26
LONG TERM...30
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1242 AM EST MON JAN 12 2015
.SYNOPSIS...
LOW PRESSURE SYSTEM AND MOSTLY RAIN TONIGHT. A COLD FRONT MOVES
THROUGH ON MONDAY. WEAK WAVE OF LOW PRESSURE SOUTH POSSIBLE MONDAY
NIGHT INTO TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
830 PM UPDATE. ALTHOUGH MOST TEMPERATURES REMAIN ABOVE
FREEZING...ENOUGH REPORTS OF LOCAL ICING WHERE GROUND IS STILL COLD
ENOUGH HAS PROMPTED AN EXPANSION OF THE FREEZING RAIN ADVISORY TO
COVER MOST OF THE AREA EXCEPT FOR SOUTHWEST VIRGINIA TIL 1 AM. THE
PREVIOUS FREEZING RAIN ADVISORIES REMAIN AS IS. TEMPERATURES WILL
FINALLY BE RISING LATER TONIGHT.
PREVIOUS DISCUSSION...
630 PM UPDATE. PRECIP MOVED IN FASTER AND MADE ADJUSTMENTS IN POPS
ACCORDINGLY. ALSO INCLUDED SOME VERY LIGHT ICE PELLETS AND OR
FREEZING RAIN FOR MOST AREAS FOR 2-3 HOURS THIS EVENING...OUTSIDE OF
ADVISORY AREAS AND UP UNTIL FREEZING RAIN ADVISORIES BEGIN FOR THE
OTHER AREAS. ALL IN ALL...SOME SLIPPERY SPOTS POSSIBLE THIS EVENING
AND ADDRESSED IN SPECIAL WEATHER STATEMENT ISSUED EARLIER.
OTHERWISE...OUTSIDE OF ADVISORY AREAS PRECIP SHOULD BE ALL RAIN BY
03Z AS TEMPS BEGIN TO INCH UP AGAIN.
PREVIOUS DISCUSSION...
REMAIN CONCERNED WITH THE MODEL TRENDS OF GETTING WARMER FOR
TONIGHT IN SOUTHEAST OHIO AND EXTREME NORTHWESTERN WV. MET/MAV AND
LAV GUIDANCE ARE WARMER THAN THE FORECAST...BUT THE HRRR STILL SHOWS
WET BULBING CAUSING ISSUES. WITH SUCH LOW DEW POINTS
CURRENTLY...FROZEN GROUND...AND ADVISORIES ALREADY IN PLACE...WILL
HOLD TIGHT...BUT EVENING SHIFT WILL NEED TO MONITOR THIS CLOSELY.
HRRR AND NAM SOUNDINGS SHOWING POTENTIAL PROBLEMS IN THE SOUTHEAST
UPSLOPE AREAS OF THE NORTHERN MOUNTAINS AS WELL. IN THIS REGION
HOWEVER...LAV GUIDANCE IS SHOWING TEMPERATURE HOOVERING RIGHT AROUND
FREEZING AT LWB...WHICH IS NOT NORMALLY THE COLDEST SPOT. WITH
GROUND FROZEN...THINK THAT POCKETS OF FREEZING RAIN A GOOD BET. WILL
ISSUE A FREEZING RAIN ADVISORY OVERNIGHT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
WITH THE FRONTAL BOUNDARY OFF TO THE SOUTHEAST...WILL BE INFLUENCED
BY A DEVELOPING INVERTED SURFACE TROUGH SETTING UP ALONG THE
MOUNTAINS IN COMBINATION WITH A WEAK MID AND UPPER LEVEL WAVE. THE
RESULT IN THE GRIDS IS NOT TOO MUCH OF A CHANGE IN TERMS OF THE
POPS...KEEPING THE LOW END POPS OVER THE MOUNTAINS BEFORE ENDING
WEDNESDAY. LARGELY BASED THE POPS ON LOW-MID LEVEL LAYER
FRONTOGENESIS WHICH IS ON THE WEAKER SIDE...BUT STILL PRESENT WHEN
LOOKING AT THE NAM.
AN OVERRUNNING SITUATION WILL BE PRESENT WITH THE MOISTURE OVER THE
MOUNTAINS AS THE TROUGH SETS UP AND WILL KEEP IT SIMPLE IN THE
WEATHER GRIDS BY USING THE WARM LAYER ALOFT FROM THE NAM. THIS
CREATES BRIEF SLEET/FREEZING RAIN POTENTIAL BEFORE THE COLD AIR
ADVECTION TAKES HOLD AND TRANSITIONS THE WEATHER TYPE TO ALL SNOW
INTO TUESDAY. ALL THE WHILE...POPS WILL BE LOWERING.
NOT SEEING MUCH OF A TEMPERATURE RECOVERY TUESDAY FROM MONDAY NIGHT
GIVEN THE CLOUD COVER AND WEAK COLD AIR ADVECTION WHICH WILL BE HELD
IN CHECK BY THE MOISTURE PUSH FROM THE AFOREMENTIONED SURFACE TROUGH
FROM THE SOUTH. KEEPING IT COLD ENOUGH IN THE FORECAST FOR OFF AND
ON LIGHT SNOW OVER THE MOUNTAINS AFTER THE FULL PRECIPITATION TYPE
TRANSITION TUESDAY AND TUESDAY NIGHT...WITH SOME LOCATIONS CLIMBING
ABOVE FREEZING WEDNESDAY AS 850MB TEMPERATURES MODIFY SLIGHTLY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLDER AIR SWEEPS IN FOR A SEASONABLY COOL EXTENDED. EXPECTING A
MAINLY DRY EXTENDED IS IN THE CARDS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MIX OF VFR AND MVFR AS AREA OF RAIN MOVES NORTH. SOME SLEET STILL
POSSIBLE ACROSS NORTHERN CWA...AND SURFACE TEMPS NEAR OR JUST
BELOW FREEZING SO PATCHES OF FREEZING RAIN ALSO POSSIBLE. TEMPS
SHOULD WARM ABOVE FREEZING THROUGH THE REMAINDER OF THE
NIGHT...WITH PRECIP BECOMING RAIN AT TAF SITES. CEILINGS WILL DROP
THROUGH THE DAY AS A COLD FRONT MOVES THROUGH. HAVE IFR IN RAIN
AND LOW CLOUDS WITH THE FRONT...WITH LOWER CIGS LINGERING BEHIND
THE FRONT AS WELL. AS COLD AIR WORKS IN ALOFT...RAIN WILL CHANGE
TO SNOW OR SLEET BEHIND THE FRONT. LIGHT AND VARIABLE WINDS AHEAD
OF THE FRONT FOR THE LOWLANDS WITH MORE CONSISTENT SOUTHERLY FLOW
IN THE MOUNTAINS. WINDS WILL BECOME NW BEHIND THE FRONT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING OF LOWERING CEILINGS AND VISIBILITY
RESTRICTIONS COULD VARY.
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 MON 01/12/15
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H H H H H H H H M M H
HTS CONSISTENCY H H H H H H H H M M M H
BKW CONSISTENCY M M M M M M M M M H M H
EKN CONSISTENCY H H H M H H M H H H L L
PKB CONSISTENCY M M M H H H L L L M M H
CKB CONSISTENCY M M M H H H M L L L L L
AFTER 06Z TUESDAY...
IFR POSSIBLE INTO TUESDAY...ESPECIALLY ACROSS THE MOUNTAINOUS COUNTIES.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FREEZING RAIN ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR
WVZ005>008-013>020-024>032-034>040.
FREEZING RAIN ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
WVZ009>011.
FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR WVZ046-
047.
OH...FREEZING RAIN ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR
OHZ086-087.
FREEZING RAIN ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
OHZ075-076-083>085.
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR OHZ066-
067.
KY...FREEZING RAIN ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR
KYZ101>103-105.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...RPY/JMV
SHORT TERM...26
LONG TERM...30
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS PORTLAND OR
844 PM PST SUN JAN 11 2015
.SYNOPSIS...A WEAK FRONT WILL CONTINUE LIGHT RAIN AND MOUNTAIN SNOW
ACROSS NW OREGON TONIGHT. SOME RESIDUAL SHOWERS WILL LINGER THROUGH
MONDAY IN NORTHWEST FLOW BEHIND THE SYSTEM. AN UPPER RIDGE WILL BUILD
MONDAY NIGHT AND TUESDAY FOR DRY BUT STABLE CONDITIONS THROUGH AT
LEAST WEDNESDAY. DRY WEATHER WITH AREAS OF VALLEY FOG IS EXPECTED
DURING THIS TIME AS WELL AS GUSTY EAST WINDS THROUGH THE GORGE AND
PARTS OF THE NORTHERN WILLAMETTE VALLEY. AN UPPER TROUGH WILL REPLACE
THE RIDGE WEDNESDAY WITH RAIN RETURNING LATE IN THE WEEK.
&&
.SHORT TERM...TONIGHT THROUGH WEDNESDAY...RAINFALL FROM A WEAK WARM
FRONT...ASSISTED BY A 90-100 KT NWLY JET...HAS BEEN DECREASING OVER
THE COUPLE OF HOURS ACROSS THE AREA. NCEP WRF AND HRRR PCPN FIELDS
INDICATE MOST OF THE RAIN OVERNIGHT WILL BE FOCUSED IN THE SOUTHERN
HALF OF THE FORECAST AREA. HOWEVER BASED ON CURRENT OBS AND RADAR
TRENDS IT APPEARS THE FOCUS IS FURTHER SOUTH THAN MODELS INDICATE SO
HAVE ADJUSTED POPS AND QPF ACCORDINGLY. SNOW LEVELS WILL HOVER
AROUND 4000 TO 4500 FEET WITH 1 TO 3 INCHES OF NEW SNOW POSSIBLE FOR
THE CASCADE PASSES...ESPECIALLY THE WILLAMETTE PASS. LAST DAYLIGHT
IMAGES FROM CAM ABOVE 5000 FEET SHOW ENOUGH SNOW TO COMPLETELY COVER
BARE GROUND. SO MAYBE AROUND ONE INCH HAS FALLEN SO FAR.
SHOWERS WILL DECREASE LATER TONIGHT THROUGH MONDAY MORNING AS THE
FRONT AND TRAILING JET MOVES SOUTHEAST...THEN END MONDAY NIGHT AS AN
UPPER RIDGE BUILDS OVER THE PACIFIC NW. VALLEY FOG SHOULD FORM IN
LATE MONDAY NIGHT AND TUESDAY MORNING. EAST WINDS WILL DEVELOP
TUESDAY AND HELP CLEAR THE FOG ALONG THE COAST...AND AREAS OF THE
NORTHERN WILLAMETTE VALLEY NEAR THE ENTRANCE OF THE COLUMBIA RIVER
GORGE. HOWEVER THE CENTRAL AND SOUTH WILLAMETTE VALLEY AREAS WILL
ONCE AGAIN BE UNDER VERY STABLE CONDITIONS FOR A FEW DAYS. THE RIDGE
WILL HOLD TUESDAY NIGHT AND WEDNESDAY WITH ANOTHER NIGHT OF FOG
INLAND...AND CLEAR SKIES FOR THE COAST.
THE MODELS ARE COMING IN BETTER AGREEMENT THAT AN UPPER TROUGH WILL
MOVE INTO THE NE PACIFIC WEDNESDAY AND PUSH THE UPPER RIDGE EASTWARD
WEDNESDAY AFTERNOON AND EVENING. TJ /MH
.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY NIGHT...AN UPPER TROUGH
WILL REPLACE THE UPPER RIDGE WEDNESDAY NIGHT AND THE MODELS SUGGEST
THAT A WEAK FRONT MAY PRODUCE SOME DRIZZLE OR RAIN FOR NW OREGON AND
SW WASHINGTON LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. A STRONGER
FRONT THEN WILL MOVE THROUGH THURSDAY NIGHT OR FRIDAY. MODELS
FORECAST THAT THIS FRONT WILL HAVE A TAP INTO SUBTROPICAL MOISTURE
WITH WATER VAPOR TRANSPORT AIMED TOWARDS OREGON. WAVES DEVELOPING
ALONG THE FRONT MAY MAINTAIN RAIN OVER THE REGION THROUGH NEXT
WEEKEND. IF THIS PANS OUT THE REGION COULD GET SEVERAL OF INCHES OF
RAIN THURSDAY NIGHT THROUGH SATURDAY NIGHT. SNOW LEVELS WILL BE
HIGH...ABOVE 5000 FEET AND ABOVE THE CASCADE PASSES. THERE MAY BE A
BREAK IN RAIN SUNDAY AND EARLY NEXT WEEK. TJ
&&
.AVIATION...RAIN HAS MOSTLY CLEARED THE AREA THIS EVENING ALTHOUGH
MVFR TO LOW VFR CLOUDS REMAIN. MODELS ARE FAVORING FOG AND IFR
STRATUS FORMATION IN THE HIO AND LOWER COLUMBIA AREAS AS WELL AS
THE CENTRAL AND SOUTH WILLAMETTE VALLEY OVERNIGHT AND INTO MONDAY
MORNING. ELSEWHERE...COULD SEE SOME MVFR FOG AND CIGS DURING THE
SAME TIME PERIOD. THE ONLY LOCATION WHICH SHOULD NOT SEE ANY FOG IS
EAST OF PDX TOWARD THE GORGE WHERE EASTERLY WINDS WILL CONTINUE
AND PRECLUDE FOG...BUT SOME MVFR STRATUS MAY DEVELOP MONDAY EVEN
THERE. COAST AND NORTH VALLEY SHOULD IMPROVE TO VFR MONDAY
MORNING WITH CENTRAL AND SOUTH VALLEY AS WELL AS LOWER COLUMBIA
TAKING A BIT LONGER AND POTENTIALLY STAYING UNDER MVFR CIGS AND BR
FOR MOST OF THE DAY AS HIGH PRESSURE MOVES BACK INTO THE AREA.
KPDX AND APPROACHES...CIGS LIKELY LOWER TO LOW MVFR TONIGHT WITH
ABUNDANT LOW LEVEL MOISTURE...BUT DO NOT EXPECT DENSE FOG.
CONDITIONS SHOULD IMPROVE TO VFR BY LATE MONDAY MORNING. BOWEN
&&
.MARINE...VERY MINOR TWEAKS TO NEAR-TERM WINDS AND SEAS THIS
EVENING BUT IN GENERAL FORECAST APPEARS TO BE WELL ON TRACK.
PREVIOUS DISCUSSION FOLLOWS. BOWEN
WINDS HAVE INCREASED A BIT THIS AFTERNOON WITH AN APPROACHING
FRONTAL SYSTEM...BUT GENERALLY NW AROUND 15 KT WITH SOME GUSTS TO
20 KT. WIND SPEEDS WILL DECREASE AGAIN EARLY MON AS HIGH PRES
RETURNS TO THE WATERS. OFFSHORE WIND PATTERN WILL DEVELOP MON
AFTERNOON AND CONTINUES THROUGH AT LEAST WED. SEAS REMAIN AROUND
4-6 FT TODAY AND BELOW 10 FT THROUGH THIS TIME.
FORECAST MODELS SUGGEST A WEAK SYSTEM WILL MOVE THROUGH
WED...WITH WIND 20 KT OR LESS. HOWEVER...CONFIDENCE CONTINUES TO
INCREASE THAT GALE FORCE GUSTS WILL DEVELOP ON THU AS A STRONGER
FRONTAL SYSTEM APPROACHES THE WATERS. SEAS LIKELY BUILD INTO THE
MID TEENS FOR THIS PERIOD. UNCERTAINTY FOR FRI AND BEYOND HOWEVER
STILL REMAINS SIGNIFICANT. ONE FORECAST MODEL CONTINUES TO DEPICT
A STRONG LOW NEAR 135W AND GIVEN THE RUN TO RUN CONSISTENCY AND
GENERAL SUPPORT FROM OTHER GUIDANCE...TRENDED THE FORECAST
TOWARDS STRONGER WIND AND BUILDING SEAS FOR THE WEEKEND. WHILE
SOME DETAILS STILL NEED TO BE RESOLVED...IT APPEARS THAT A MORE
ACTIVE PATTERN CAN BE EXPECTED FOR THE END OF THE WEEK AND NEXT
WEEKEND. CULLEN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
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 FORT WORTH TX
1147 PM CST SUN JAN 11 2015
.AVIATION...
CONCERNS...IFR TO LIFR CONDITIONS EXPECTED THROUGH MIDDAY MONDAY.
WIND SHIFT TO THE NORTH AROUND 09Z IN THE METROPLEX...AROUND 11Z
AT WACO.
SATELLITE IMAGERY AT 05Z SHOWS THAT AREAS FROM CHILDRESS /KCDS/
TO GRAHAM /KRPH/ TO BROWNWOOD /KBWD/ EASTWARD REMAIN UNDER LOW
CLOUDS AND THESE CLOUDS CONTINUE TO SLOWLY WORK THEIR WAY
WESTWARD. EXPECT LIFR CONDITIONS WITH CEILINGS BELOW 500 FEET AND
VISIBILITIES AROUND 1 MILE OR LESS WITH FOG AND DRIZZLE TO
PREVAIL AT THE METROPLEX TAF SITES THROUGH MID MORNING. A PRE-
FRONTAL TROUGH THAT EXTENDED FROM SOUTHEASTERN KANSAS THROUGH
SOUTHWESTERN OKLAHAOMA INTO EAST CENTRAL NEW MEXICO AT 05Z WILL
CONTINUE TO MOVE SOUTHEAST. THIS BOUNDARY SHOULD MOVE THROUGH THE
METROPLEX AROUND 09Z AND THROUGH WACO AROUND 11Z. WINDS WILL
SHIFT TO THE NORTH NORTHEAST AT 7 TO 9 KNOTS AS THIS BOUNDARY
PASSES AND VISIBILITIES SHOULD IMPROVE SLIGHTLY. THE ACTUAL COLD
FRONT CURRENTLY /AS OF 05Z/ EXTENDS FROM NORTHEASTERN KANSAS
SOUTHWEST INTO SOUTHEAST COLORADO. THIS FRONT WILL MOVE THROUGH
THE METROPLEX BY 15Z AND THROUGH WACO 16-17Z. WINDS WILL BECOME
MORE NORTHERLY AND SPEEDS WILL INCREASE TO AROUND 15 KNOTS WITH
THE TRUE FRONTAL PASSAGE. EXPECT CEILINGS TO RISE INTO THE
500-900 FEET RANGE WITH THIS BOUNDARY AND ANY REMAINING FOG
SHOULD DISPERSE. CEILINGS SHOULD IMPROVE INTO THE LOWER END OF
MVFR BY 19-20Z AND UP TO AROUND 2000 FEET LATE AFTERNOON /22Z/.
VFR CEILINGS ARE EXPECTED AFTER 13/07Z AS INDICATED IN THE
EXTENDED PORTION OF THE KDFW TAF.
58
&&
.UPDATE...
MORE WIDESPREAD AREAS OF FOG AND DRIZZLE HAVE DEVELOPED ACROSS THE
REGION AHEAD OF A COLD FRONT CURRENTLY MOVING SOUTH THROUGH
OKLAHOMA. EXPECT THE FOG AND DRIZZLE TO PERSIST TONIGHT ACROSS
ROUGHLY THE EASTERN 2/3RDS OF THE AREA WHERE OVERCAST SKIES WILL
PERSIST AS WELL. CLOUD COVER IS A CHALLENGE TONIGHT BUT NOT
NECESSARILY A HINDRANCE TO THE FORECAST. MOST OF THE MODELS HAVE
THE CURRENT LOW CLOUD COVER STARTING TO ERODE FROM WEST TO EAST
BEGINNING IN THE LAST HOUR...BUT THE WESTERN EDGE OF THE CLOUDS IS
NOT ERODING AND IS EVEN BUILDING WEST SOME. THE HRRR IS THE ONLY
MODEL INDICATING THIS TREND AND IT KEEPS CLOUDY SKIES THROUGH THE
NIGHT. WILL ADJUST THE SKIES TO INDICATE CLOUDY/OVERCAST SKIES
THROUGH THE NIGHT WITH SOME CLEARING IN OUR SOUTHWEST COUNTIES
LATE TONIGHT.
THE COLD FRONT WILL BEGIN MOVING INTO THE REGION LATE TONIGHT WITH
THE COLDER AND DRIER AIR ARRIVING ON MONDAY. THEREFORE...ADJUSTED
DEWPOINTS UP SEVERAL DEGREES OVERNIGHT WITH THE DRYING TREND
BEING DELAYED UNTIL TOMORROW. DUE TO THE HIGHER
DEWPOINTS...INCREASED CLOUD COVER...AND THE SLOWER ARRIVAL OF
COLD AIR ADVECTION...ALSO ADJUSTED OVERNIGHT LOW TEMPS UP TO
VALUES VERY NEAR CURRENT TEMPERATURE READINGS. OVERNIGHT LOWS WILL
TEND TO REMAIN NEARLY STEADY THROUGH THE NIGHT. WITH COLD AIR
ADVECTION COMMENCING TOMORROW...SEVERAL LOCATIONS IN OUR NORTHWEST
WILL BARELY SEE ANY TEMPERATURE CHANGE TONIGHT AND TOMORROW.
WE DO NOT ANTICIPATE WIDESPREAD DENSE FOG TO OCCUR TONIGHT...BUT
THERE COULD BE SEVERAL AREAS THAT FALL BELOW 1 MILE THROUGHOUT THE
NIGHT WITH SOME POSSIBLY FALLING AROUND 1/4 MILE AT TIMES. WILL
NOT ISSUE A DENSE FOG ADVISORY AT THIS TIME.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 302 PM CST SUN JAN 11 2015/
THE SHORTWAVE TROUGH THAT BROUGHT RAIN TO MOST OF THE AREA LAST
NIGHT WAS LOCATED OVER SOUTHWEST MISSOURI EARLY THIS AFTERNOON PER
WATER VAPOR SATELLITE IMAGERY. EARLY AFTERNOON VISIBLE SATELLITE
IMAGERY SHOWED A DECK OF LOW STRATUS CLOUDS OVER MOST OF THE
CWA...WITH A SHARP CUT-OFF TO CLEAR SKIES APPROXIMATELY ALONG A
WICHITA FALLS TO POSSUM KINGDOM LAKE LINE. THIS CLEARING LINE WAS
MAKING SLOW PROGRESS TO THE EAST...BUT THIS CLEARING WILL LIKELY
ONLY MAKE IT TO MINERAL WELLS BEFORE SUNSET. AS A RESULT...MOST OF
NORTH AND CENTRAL TEXAS WILL SEE TEMPERATURES HOLD STEADY IN THE
UPPER 30S TO LOW 40S THROUGH THIS EVENING.
FOR TONIGHT THROUGH WEDNESDAY...WATER VAPOR SATELLITE IMAGERY
OBSERVED SHORTWAVE TROUGHS ALONG THE CO/WY BORDER...AND JUST OFF
SHORE THE SOUTHERN CALIFORNIA COAST. A STRONGER UPPER TROUGH WAS
LOCATED OFF THE OREGON COAST...EXTENDING NORTHWEST OVER THE FAR
NORTHEAST PACIFIC OCEAN. THESE FEATURES ARE EXPECTED TO HAVE SOME
IMPACT ON OUR LOCAL AREA FORECAST THROUGH WEDNESDAY
THE CO/WY TROUGH IS EXPECTED TO MOVE EAST OVER THE CENTRAL PLAINS
TONIGHT SENDING A COLD FRONT SOUTH ACROSS THE SOUTH PLAINS. THIS
COLD FRONT IS EXPECTED TO MOVE ACROSS THE CWA BEFORE SUNRISE
TOMORROW MORNING. DUE TO THE UPPER LEVEL LIFT/SUPPORT REMAINING SO
FAR NORTH OF TEXAS...DO NOT EXPECT MUCH IN THE WAY OF RAIN CHANCES
ALONG THIS FRONT. LOW-LEVEL MOISTURE ALREADY IN PLACE WILL BE
LIFTED BY THE FRONT AS IT MOVES THROUGH...SO THINK THAT THERE WILL
BE A CHANCE FOR SPRINKLES OR DRIZZLE JUST ABOUT ANYWHERE ACROSS
NORTH AND CENTRAL TEXAS TOMORROW MORNING ALONG AND BEHIND THE
FRONT. HAVE A MIXTURE OF SPRINKLES AND PATCHY FOG IN THE FORECAST
TO ACCOUNT FOR THIS LOW-LEVEL MOISTURE LIFTING OVER THE FRONT
TOMORROW MORNING.
CHANCES FOR LIGHT RAIN DIMINISH BY LATE MORNING AS STRONGER NORTH
WINDS SEND SOME SLIGHTLY DRIER AIR INTO THE REGION. NORTH WINDS
ARE EXPECTED TO PICK UP TO 15 TO 20 MPH BY NOON TOMORROW. WIND
GUSTS ARE EXPECTED TO BE AS HIGH AS 25 TO 30 MPH AT TIMES.
TEMPERATURES ARE EXPECTED TO REMAIN COOL BEHIND THE FRONT...BUT
THE AIRMASS MOVING IN BEHIND THE FRONT DOES NOT LOOK ARCTIC IN
NATURE...SO A DRAMATIC COOL DOWN IS NOT EXPECTED AT THIS TIME.
THE SOUTHERN CALIFORNIA TROUGH IS EXPECTED TO MOVE OVER NORTH
TEXAS MONDAY NIGHT. AT THIS TIME MODEL GUIDANCE INDICATES THAT
THERE WILL NOT BE ENOUGH MOISTURE IN PLACE FOR ANY SIGNIFICANT
RAIN CHANCES ASSOCIATED WITH THIS SECONDARY TROUGH TOMORROW NIGHT.
HOWEVER WE WILL HAVE TO ASSESS THE LOW-LEVEL MOISTURE PROFILES
MONDAY EVENING TO SEE HOW MUCH DRY AIR HAS ADVECTED INTO THE
REGION AFTER BREEZY NORTH WINDS MONDAY AFTERNOON. AS LONG AS LOW-
LEVELS ARE NOT SATURATED...RAIN CHANCES SHOULD REMAIN NEAR ZERO
MONDAY NIGHT AS THIS TROUGH MOVES OVERHEAD. IF WE ARE
SATURATED...DRIZZLE WOULD BE MORE LIKELY. DRIZZLE IS USUALLY NOT
A BIG DEAL...HOWEVER TEMPERATURES ARE EXPECTED TO FALL BELOW
FREEZING BY TUESDAY MORNING FOR A LARGE PORTION OF THE CWA.
FREEZING DRIZZLE COULD BE AN ISSUE IF WE DO NOT DRY OUT ENOUGH
MONDAY AFTERNOON. AT THIS TIME THINK THAT WE WILL REMAIN DRY
ENOUGH TO AVOID FREEZING DRIZZLE CONCERNS MONDAY NIGHT/TUESDAY
MORNING.
THE OREGON UPPER TROUGH IS EXPECTED TO MOVE OVER THE SOUTHERN
PLAINS FROM TUESDAY NIGHT INTO WEDNESDAY. AT THIS TIME GUIDANCE HAS
CONTINUED ITS TREND ADVERTISING A WEAKER...STRONGLY POSITIVELY
TILTED...TROUGH MOVING OVER THE AREA. WITH LIMITED MOISTURE TO
WORK WITH...THE ADVERTISED WEAK LIFT ASSOCIATED WITH THIS TROUGH
LOOKS UNLIKELY TO PRODUCE ANY SIGNIFICANT PRECIPITATION ACROSS
NORTH AND CENTRAL TEXAS. HOWEVER...THIS TROUGH LOOKS STRONG RIGHT
NOW ON WATER VAPOR SATELLITE IMAGERY...SO WE WILL HAVE TO MONITOR
THIS TROUGH OVER THE NEXT 48 HOURS AND MAKE SURE IT DOES WEAKEN AS
IT APPROACHES. ANY PRECIPITATION ALONG THE RED RIVER ON TUESDAY
NIGHT INTO WEDNESDAY MORNING LOOKS LIKE IT WOULD BE SNOW...OR A
RAIN/SNOW MIX. NO ACCUMULATIONS ARE EXPECTED AS THIS
TIME...HOWEVER STRONGER LIFT COULD EASILY RESULT IN SOME MINOR
ACCUMULATIONS OF SNOW ACROSS THE NORTHERN COUNTIES OF THE CWA.
HAVE A 20 PERCENT CHANCE OF LIGHT RAIN ACROSS THE ENTIRE CWA ON
WEDNESDAY AS THE TROUGH MOVES EAST OVER THE AREA.
BEHIND THE MID-WEEK TROUGH...MOST MODEL GUIDANCE INDICATES THAT
WEAK RIDGING...OR POSSIBLY JUST ZONAL FLOW...TAKES SHAPE OVER THE
SOUTHERN PLAINS FOR LATE THIS WEEK INTO THE WEEKEND. AS A
RESULT...HAVE A DRY FORECAST IN PLACE WITH TEMPERATURES WARMING
EACH DAY DUE TO THE EXPECTATION FOR A RETURN TO PERSISTENT
SOUTHERLY WINDS BY LATE THIS WEEK. MODEL GUIDANCE DOES HINT AT THE
POTENTIAL FOR A LARGE UPPER TROUGH TO AFFECT THE REGION EITHER
LATE SUNDAY OR INTO EARLY NEXT WEEK. DID NOT PLACE ANY MENTION OF
POPS IN THE FORECAST AT THIS TIME FOR THIS SYSTEM AS MOST GUIDANCE
DELAYS ITS PASSAGE OVER THE REGION UNTIL EARLY NEXT WEEK.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 39 42 30 38 31 / 10 10 10 10 10
WACO, TX 41 44 32 42 32 / 10 10 10 10 20
PARIS, TX 36 41 31 38 29 / 10 10 10 10 10
DENTON, TX 39 42 28 37 28 / 10 10 10 10 20
MCKINNEY, TX 39 42 29 38 29 / 10 10 10 10 10
DALLAS, TX 40 42 31 39 32 / 10 10 10 10 10
TERRELL, TX 41 44 32 39 31 / 10 10 10 10 10
CORSICANA, TX 42 44 33 42 32 / 10 10 10 10 10
TEMPLE, TX 42 47 33 43 32 / 10 10 10 10 20
MINERAL WELLS, TX 39 41 28 38 28 / 10 10 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/82
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1023 PM MST SUN JAN 11 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 256 PM MST SUN JAN 11 2015
TONIGHT...OUR MIDNIGHT SHIFT SHORT TERM FORECASTER SET THE PLATE
WELL WITH RESPECT TO OUR SHORT TERM FORECAST FOR THE NEXT FEW
DAYS. NEXT ARCTIC TYPE COLD FRONT PLOWING SOUTH ACROSS OUR
NORTHERN COUNTIES AT EARLY AFTERNOON WITH TEMPERATURES ONLY IN THE
UPPER TEENS TO MID 20S AT CHADRON AND ALLIANCE...AND IN THE MID TO
UPPER 30S SOUTH OF THE FRONT. BRISK NORTH WINDS ALREADY EVIDENT
ACROSS THE NEBRASKA PANHANDLE AND OVER FAR EASTERN WYOMING WILL
CONTINUE THE COLD AIR ADVECTION AND FALLING AFTERNOON
TEMPERATURES.
WITH WEAK SHORTWAVE TROUGH MOVING OVERHEAD...NEARLY SATURATED LOW
AND MID LEVELS AND DECENT SYNOPTIC...MESOSCALE AND UPSLOPE
LIFT...WE WILL HAVE 50 TO 100 PERCENT POPS FOR SNOW THIS EVENING
OVER MOST LOCATIONS...ESPECIALLY THE UPSLOPE FAVORED AREAS FROM
WHEATLAND TO CHEYENNE. UPWARD VERTICAL MOTION DECREASES AFTER
MIDNIGHT...SO EXPECT A CORRESPONDING DECREASE IN AREAL SNOW
COVERAGE.
MONDAY...AREAL SNOW COVERAGE WILL DECREASE AS UPWARD VERTICAL
MOTION WANES...THOUGH OROGRAPHIC TYPE SNOWS WILL CONTINUE OVER OUR
SNOWY AND SIERRA MADRE RANGES WITH SOUTHWEST FLOW ALOFT AHEAD OF
THE NEXT SHORTWAVE TROUGH ALOFT. CONTINUED COLD IN THE ARCTIC
AIRMASS...ESPECIALLY EAST OF INTERSTATE 25 WITH TEMPERATURES
HOLDING BELOW FREEZING.
MONDAY NIGHT...NAM...GFS AND ECMWF CONTINUING THE SIMILAR TREND
FROM THE MODEL RUNS SATURDAY MORNING...WITH THE NAM FURTHER NORTH
WITH THE APPROACHING POSITIVELY TILTED SHORTWAVE TROUGH ALOFT OVER
WESTERN COLORADO...WITH THE GFS AND ECMWF FURTHER SOUTH.
WIDESPREAD OROGRAPHIC SNOWS WILL CONTINUE OVER THE SNOWY AND
SIERRA MADRE RANGES IN ADVANCE OF THE TROUGH ALOFT...WITH SOME UVV
NOTED AND MOIST ATMOSPHERIC COLUMN...WILL SEE A CHANCE OF SNOW
OUTSIDE OF THE MOUNTAINS WEST OF INTERSTATE 25.
TUESDAY...AFOREMENTIONED TROUGH ALOFT MOVES ACROSS CENTRAL AND
SOUTHERN COLORADO WITH THE DEEPER MOISTURE AND BEST UPWARD
VERTICAL MOTION SOUTH OF WYOMING...THOUGH WILL STILL SEE
OROGRAPHIC SNOWS OVER OUR SNOWY AND SIERRA MADRE RANGES AND
SCATTERED SNOW SHOWERS ELSEWHERE WEST OF INTERSTATE 25...DRY
ELSEWHERE. CONTINUED COLD WITH THICK CLOUD COVER AND A SLOWLY
MODERATING ARCTIC TYPE AIRMASS. WE ARE STILL THINKING TOTAL
SNOWFALL THROUGH TUESDAY OF 1 TO 3 INCHES AT LOWER
ELEVATIONS...WITH 4 TO 7 INCHES OVER THE MOUNTAINS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 256 PM MST SUN JAN 11 2015
A DRY AND WARMER PERIOD AHEAD WITH BREEZY TO LOCALLY WINDY
CONDITIONS RETURNING FOR THE SECOND HALF OF NEXT WEEK. NW FLOW
WILL PREVAIL WED AND WED NT BEHIND SHORTWAVE ENERGY DIVING INTO
THE SRN PLAINS. WED WILL BE BREEZY WITH WIND GUSTS OF 15-25 MPH
RETURNING. HIGHEST VALUES IN SE WY. WED WILL BE THE LAST COOLISH
DAY WITH HIGHS RISING INTO THE 30S. TRANSITORY RIDGE WILL PASS
OVERHEAD ON THURSDAY AHEAD OF SHARP AND MOISTURE STARVED SHORTWAVE
DIVING SE FROM THE PACNW. WAA AND INCREASING LLVL GRADIENTS AHEAD
OF THIS SYSTEM WILL WARM THURSDAYS HIGHS WELL INTO THE 30S
WEST...WITH SOLIDLY INTO THE 40S ON THE ERN PLAINS. H7 WIND PROGS
BEGIN TO TICK UP TO 30-40 KNOTS ON THURSDAY AS WELL...SO WIND
GUSTS OF 35-45 MPH CAN BE EXPECTED IN THE TYPICALLY WINDY AREAS OF
SE WYOMING. SHORTWAVE ENERGY DIVES THRU THE CWA THU NT...WITH
ZONAL FLOW RETURNING FOR FRI-SAT. DEPENING ON THE TRAJECTORY OF
THE SHORTWAVE...MAY SEE A BORA WIND EVENT EARLY FRIDAY
MORNING...WITH STRONG SUBSIDENCE IN THE WAKE OF FROPA ON FRIDAY.
H7 WINDS CONTINUE TO INCREASE TO 50-60 KNOTS EARLY FRIDAY AND
FRIDAY. HAVE INCREASED WIND SPEEDS AS A RESULT. WILL MORE THAN
LIKELY NEED WIND HIGHLIGHTS FOR THIS PERIOD IN TIME. 40-50 KNOT
H7 WINDS WILL PERSIST FRI NT AND SAT AS WELL. SO MAY SEE GUSTS
STAY UP ACROSS THE FAVORED WIND CORRIDOR FRI NT AND SAT.
FORTUNATELY WARMER TEMPS WILL CONTINUE FOR THE ERN PLAINS ON FRI-
SAT WITH HIGHS REACHING CLIMBING INTO THE 40S TO NR 50.
SIGNIFICANT MODEL DIFFERENCES EMERGE FOR THE LATTER HALF OF NEXT
WEEKEND WITH THE EURO SHOWING A STRONG ZONAL JET WHILE THE GFS
SHOWS TROUGHING INTO THE WRN CONUS. IN EITHER CASE DRY CONDITIONS
WILL CONTINUE WITH ABOVE NORMAL TEMPS AND BREEZY CONDITIONS
CONTINUING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1020 PM MST SUN JAN 11 2015
LATEST HRRR GUIDANCE USED IN THE 06Z TAFS THIS EVENING. SHOULD SEE
A SOLID IFR/LIFR EVENT FOR KCYS IN NORTHEAST UPSLOPE FLOW AS WELL
AS OUR SOUTHERN NEBRASKA PANHANDLE AIRPORTS. PROLONGED EVENT
EXPECTED AS THE FRONT STALLS OVER THE AREA AND UPSLOPING WINDS
CONTINUE. EXPECT THIS TO LAST THROUGH TUESDAY BEFORE WEST WINDS
RETURN TO SCOUR OUT THE LOW LEVEL MOISTURE.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MST SUN JAN 11 2015
FORECASTED HUMIDITIES AND WINDS SUGGEST MINIMAL ISSUES.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM...CAH
AVIATION...GCC
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1027 AM EST MON JAN 12 2015
.SYNOPSIS...
A PRESSURE TROUGH WILL REMAIN ALONG THE COAST TODAY. A COLD FRONT
APPROACHING FROM THE NORTHWEST WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE FRONT WILL BE NEAR THE COAST TUESDAY THROUGH TUESDAY
NIGHT. THE FRONT WILL SHIFT FARTHER OFFSHORE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...RADAR SHOWS AREA OF RAIN WITH A FEW EMBEDDED THUNDERSTORMS
MOVING INTO OUR CWA FROM THE SOUTH. THIS APPEARS TO BE ASSOCIATED
WITH A SHORT WAVE APPROACHING THE REGION. THE HRRR HAS CAPTURED
THIS TREND AND SHOWS WIDE SPREAD RAIN MOVING THROUGH THE CWA
THROUGH THE AFTERNOON. WILL LEAN TOWARD THIS SOLUTION AND HAVE
ADJUSTED POPS TO REFLECT THIS...80 TO 100 PERCENT WITH HIGHEST
VALUES TO THE EAST. TEMPERATURES WILL BE STEADY TO SLOWLY RISING
INTO THE LOWER TO MID 40S NORTH AND LOWER TO MID 50S SOUTH.
TONIGHT...MODELS SHOW MOISTURE MORE SHALLOW BEHIND THE MID- LEVEL
SHORTWAVE TROUGH. A COLD FRONT CONTINUES TO APPROACH FROM THE
NORTHWEST BUT APPEARS TO STAY OUT OF THE AREA UNTIL TUESDAY. POPS
WILL DECREASE OVERNIGHT INTO THE 20-40 PERCENT RANGE. FOG MAY BE
AN ISSUE WITH HIGH LOW-LEVEL MOISTURE AND THE DRYING ALOFT.
TEMPERATURES WILL BE NEARLY STEADY OVERNIGHT FALLING ONLY A COUPLE
OF DEGREES. LIGHT WIND WILL CONTINUE AHEAD OF THE FRONT.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
COOLING WILL OCCUR BEHIND THE COLD FRONT TUESDAY. ISENTROPIC LIFT
PLUS ANOTHER IN THE SERIES OF MID-LEVEL SHORTWAVE TROUGHS IN THE
ACTIVE SOUTHERN STREAM MAY BRING RAIN. THE GUIDANCE CONSENSUS
SUPPORTS POPS OF 40 TO 50 PERCENT. THE TEMPERATURE GUIDANCE IS
LIKELY TOO WARM BUT STILL BELIEVE IT WILL BE WARM ENOUGH FOR ALL
LIQUID PRECIPITATION. THE NAM AND GFS ARE IN AGREEMENT KEEPING
SURFACE WET-BULB TEMPERATURES ABOVE FREEZING THROUGH THE DAY.
THE PRECIPITATION MAY CONTINUE TUESDAY NIGHT INTO EARLY WEDNESDAY
ASSOCIATED WITH CONTINUED WEAK ISENTROPIC LIFT AND ANOTHER IN THE
SERIES OF MID-LEVEL SHORTWAVE TROUGHS. FURTHER COOLING WILL
OCCUR TUESDAY NIGHT AND BOTH THE GFS AND NAM INDICATE WET-BULB
TEMPERATURES FALLING BELOW FREEZING IN THE NORTH PART OF THE
FORECAST AREA. THIS AREA INCLUDES THE COUNTIES OF NEWBERRY...
FAIRFIELD...KERSHAW...LANCASTER...AND CHESTERFIELD. THE MODELS ARE
IN AGREEMENT INDICATING SHALLOW MOISTURE AND WEAK LIFT WITH JUST
LIGHT PRECIPITATION AMOUNTS OF LESS THAN ONE-TENTH OF AN INCH. WE
CONTINUED THE FORECAST OF A CHANCE OF LIGHT FREEZING RAIN OR
DRIZZLE IN THE NORTH PART FOR LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING CLOSE TO THE TIMING OF THE NAM AND GFS FREEZING WET-BULB
TEMPERATURES AND THE SREF GUIDANCE.
LATER WEDNESDAY MORNING THE PRECIPITATION CHANCE WILL LIKELY
FURTHER DIMINISH. THE MODELS HAVE SHOWN SOME CONSISTENCY WITH THE
AREA UNDER MID-LEVEL SHORTWAVE RIDGING WITH LITTLE OR NO
ISENTROPIC LIFT DURING MUCH OF THE DAY. HOWEVER...MODEL TIME SECTIONS
SHOW HIGH LOW-LEVEL MOISTURE CONTINUING ACROSS THE AREA WEDNESDAY
AND WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE SOUTHERN STREAM WILL LIKELY REMAIN ACTIVE THURSDAY. THE ECMWF
WAS MOVE PRONOUNCED MOVING DEEPER MOISTURE INTO THE AREA. THE GFS
MOS HAD A POP NEAR 20 PERCENT AT COLUMBIA COMPARED TO THE ECMWF
POP OF ABOUT 60 PERCENT. WE FORECASTED CHANCE POPS. ONCE AGAIN...
PRECIPITATION TYPE WILL BE A CONCERN BUT FOR NOW BASED ON THE
LATEST GFS THERE APPEARS TO BE JUST ENOUGH WARMING IN THE LOWEST
LAYERS FOR ALL LIQUID PRECIPITATION. THE GFS AND ECMWF DISPLAY DRY
RIDGING DOMINATING SATURDAY. THE ECMWF MAINTAINED DRY CONDITIONS
SUNDAY...BUT THE GFS HAD SOME INCREASE IN MOISTURE. STILL...THE
GFS MOS HAD POPS OF ONLY AROUND 20 PERCENT SUNDAY.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
IFR/POSSIBLE LIFR RESTRICTIONS EXPECTED FOR THE TAF SITES FOR MUCH
OF THE PERIOD.
REGIONAL RADAR CONTINUES TO SHOW AREAS OF LIGHT TO MODERATE RAIN
ACROSS THE SOUTHEAST. CIGS HAVE DROPPED INTO IFR/LIFR LEVELS AND DO
NOT EXPECT MUCH IN THE WAY OF IMPROVEMENT THROUGH THE TAF PERIOD.
STRONG INVERSION EARLY THIS MORNING WITH LIGHT WINDS AT THE SURFACE
BUT WITH S WINDS AROUND 20 TO 25 KTS AT 2KFT. LIGHTNING DETECTION
PROGRAM SHOWING ISOLATED LIGHTNING IN THE AREA THAT MAY BRIEFLY
AFFECT THE TAF SITES OVER THE NEXT FEW HOURS...BUT NOT ENOUGH
CONFIDENCE TO MENTION TSRA IN THE TAFS AT THIS TIME. WINDS THROUGH
THE PERIOD WILL BE GENERALLY NORTHEASTERLY AT 6 KNOTS OR LESS...BUT
MAY GO LIGHT AND VARIABLE AT TIMES.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE TUESDAY THROUGH
FRIDAY AS SERIES OF SYSTEMS CROSS THE REGION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
855 AM EST MON JAN 12 2015
.SYNOPSIS...
A WEDGE OF HIGH PRESSURE WILL PREVAIL INLAND THIS MORNING WITH A
WEAKENING WARM FRONT NEAR THE COAST. THE FRONT WILL DISSIPATE AND
SHIFT NORTHEAST OF THE AREA TONIGHT BEFORE ANOTHER AREA OF HIGH
PRESSURE BUILDS FROM THE NORTH THROUGH THE MIDDLE OF THE WEEK. LOW
PRESSURE WILL THEN MOVE NORTHEAST OFF THE COAST THURSDAY...FOLLOWED
BY DRY HIGH PRESSURE THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
12/13Z OBSERVATIONS INDICATE THE COASTAL FRONT IS ALIGNED ALONG
THE GEORGIA AND FAR SOUTHERN SOUTH CAROLINA COAST WHERE WINDS
REMAIN BACKED NORTH TO NORTHWEST...THEN BENDS INLAND SLIGHTLY
NEAR KIAWAH INTO DOWNTOWN CHARLESTON...AWENDAW AND MCCLELLANVILLE
WHERE TEMPERATURES HAVE WARMED INTO THE LOWER 60S. INLAND...COLD
AIR DAMMING IS FIRMLY IN PLACE AND WILL MOVE LITTLE TODAY AS
INCOMING RAIN WORKS WITH LINGERING DRY AIR TO REINFORCE DIABATIC
EFFECTS. PINNING DOWN HOURLY TEMPERATURES IS PROVING TO BE NEARLY
IMPOSSIBLE AS SUBTLE DIFFERENCES IN PRECIPITATION INTENSITY...
LOCATION AND TIMING WILL PLAY HAVOC THROUGH THE DAY. INCOMING H3R
AND RAP DATA SUGGEST TEMPERATURES ACROSS INTERIOR SOUTHEAST
GEORGIA MAY BE A FEW DEGREES TOO WARM AND THE LATEST UPDATE HAS
LOWERED THEM BY SEVERAL DEGREES. HIGHS WILL RANGE FROM THE LOWER-
MID-MID 50S ROUGHLY WEST OF A HARLEYVILLE-SPRINGFIELD-GLENNVILLE
LINE WITH UPPER 50S-LOWER 60S EAST OF THERE TO THE COAST. THE
WARMEST CONDITIONS TODAY WILL BE FOUND ON THE UPPER CHARLESTON
COUNTY COAST AND POSSIBLY COASTAL MCINTOSH COUNTIES WHERE A FEW
UPPER 60S COULD OCCUR. THERE IS OBVIOUSLY A BIG BUST POTENTIAL
HERE IN SOME LOCATIONS AND UPDATES WILL BE NEEDED THROUGH THE
DAY.
LDS NETWORK CONTINUES TO PING OCCASIONAL LIGHTNING STRIKES
AND SOME ELEVATED INSTABILITY EXPECTED TO LINGER THROUGH THE
DAY...A SLIGHT CHANCE OF TSTMS HAS BEEN MAINTAINED. VISIBILITIES
HAVE BEEN AN IMPROVING TREND OVER THE PAST HOUR AS RAIN FILLS IN
FROM THE SOUTH. THE FOG REMAINS QUITE DENSE IN THE STATESBORO-
SYLVANIA AND ALLENDALE AREAS PER RECENT OBSERVATIONS/WEBCAMS...BUT
CONDITIONS WILL IMPROVE THERE OVER THE NEXT HOUR AS RAIN MOVES IN
FROM THE SOUTH.
POPS HAVE BEEN INCREASED TO 100 PERCENT ALL AREAS FOR THE NEXT
SEVERAL HOURS WITH GRIDDED POPS DIMINISHING ACROSS THE SOUTH
THROUGH THE DAY AS SHORTWAVE ENERGY EXITS...LEAVING ONLY WEAK
ISENTROPIC ASSENT IN ITS WAKE. ADDITIONAL QPF THROUGH SUNSET
LOOKS TO AVERAGE 1/2 TO 1 INCH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...RAIN CHANCES WILL BE DIMINISHING FROM SOUTHWEST TO
NORTHEAST THIS EVENING AS THE SHORTWAVE TROUGH SHIFTS OFFSHORE
ALONG WITH THE DEEPER MOISTURE. HOWEVER...ABUNDANT LOW-LEVEL
MOISTURE WILL REMAIN IN PLACE AND BECOME TRAPPED BENEATH THE
NOCTURNAL INVERSION LEADING TO ABUNDANT LOW CLOUDS AND FOG. SOME
OF THE FOG COULD BECOME DENSE AND A DENSE FOG ADVISORY MAY BE
ISSUED LATER TODAY. LOWS MAINLY IN THE MID TO UPPER 40S.
TUESDAY...COLD AIR DAMMING TO THE LEE OF THE APPALACHIANS WILL
DEVELOP AS SURFACE HIGH PRESSURE SHIFTING FROM THE GREAT LAKES
REGION INTO NEW ENGLAND WEDGES SOUTHWARD ACROSS THE MID-ATLANTIC AND
THE CAROLINAS. DEEPENING MOISTURE PROFILES...THE PASSAGE OF SEVERAL
DISTURBANCES ALOFT AND WEAK ISENTROPIC ASCENT WILL SUPPORT A CHANCE
OF RAIN AND DRIZZLE ACROSS THE AREA...ESPECIALLY IN THE AFTERNOON.
ANY PRECIPITATION INTO THE WEDGE WILL ALLOW FOR SIGNIFICANT COOLING
AS DIABATIC EFFECTS TAKE PLACE...STRENGTHENING THE WEDGE FURTHER AND
MAKING FOR A DIFFICULT TEMPERATURE FORECAST. OVERALL...EXPECT A
FAIRLY LARGE HIGH TEMPERATURE GRADIENT ACROSS THE AREA...WITH LOWER
50 FAR NORTHWEST CLOSER TO THE CORE OF THE WEDGE AND MID 60S ACROSS
PARTS OF THE GEORGIA COAST.
TUESDAY NIGHT...THE WEDGE WILL REMAIN FIRMLY IN PLACE...WITH THE
CONTINUATION OF UNSETTLED CONDITIONS. DEEP MOISTURE...ISENTROPIC
ASCENT AND A PASSING MID-LEVEL SHORT WAVE TROUGH WILL SUPPORT
MORE RAIN AND DRIZZLE. THE FORECAST SHOWS PROBABILITIES IN THE
CHANCE CATEGORY FOR MOST AREAS...BUT LIKELY ALONG PARTS OF THE
COAST. LOWS WILL RANGE FROM THE UPPER 30S IN INLAND SOUTHEAST SOUTH
CAROLINA TO THE LOWER 40S CLOSER TO THE COAST AND IN SOUTHEAST
GEORGIA.
WEDNESDAY AND WEDNESDAY NIGHT...THE PARENT HIGH WILL GRADUALLY SHIFT
OFF THE NEW ENGLAND COAST...BUT THE WEDGE WILL LINGER AS EVIDENCED
BY NORTHERLY FLOW AT THE SURFACE AND THE CONTINUED PRESENCE OF
ABUNDANT LOW LEVEL MOISTURE. WITH SOME OF THE DEEPER MOISTURE
STRIPPED AWAY ALOFT AND A LACK OF ANY SIGNIFICANT FORCING
MECHANISM...ONLY EXPECT RAIN CHANCES TO BE IN THE 20-30 PERCENT
RANGE WITH MORE DRIZZLE POSSIBLE AS WELL. TEMPERATURES WILL NOT
CLIMB OUT OF THE UPPER 40S OR LOWER 50S DURING THE DAY...WITH LOWS
IN THE UPPER 30S TO LOWER 40S.
THURSDAY...A MID AND UPPER LEVEL TROUGH WILL SHIFT EAST OF THE
MISSISSIPPI VALLEY...INDUCING CYCLOGENESIS OVER THE NORTHERN GULF OF
MEXICO. THE RESULTING SURFACE LOW WILL THEN TRANSITION INTO THE
SOUTHWEST ATLANTIC LATER IN THE DAY. DEEP MOISTURE AND FORCING FOR
ASCENT ASSOCIATED WITH A POTENT UPPER JET MOVING ALONG THE BASE OF
THE TROUGH WILL SUPPORT GOOD CHANCES FOR RAIN ACROSS THE AREA. THE
REMNANT SURFACE WEDGE WILL LIMIT HIGHS TO THE UPPER 40S AND LOWER
50S ACROSS THE AREA ONCE AGAIN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
MODELS START OFF IN REASONABLE AGREEMENT...BUT THEN SOME SIGNIFICANT
DIFFERENCES BEGIN TO DEVELOP OVER THE WEEKEND WITH RESPECT TO THE
OVERALL SYNOPTIC PATTERN. DESPITE ANY DIFFERENCES...CONDITIONS
APPEAR TO BE MUCH LESS UNSETTLED IN THE LONG TERM PERIOD.
A STRONG MID AND UPPER LEVEL TROUGH WILL CROSS THE REGION THURSDAY
NIGHT THEN SHIFT OFFSHORE ON FRIDAY. THIS WILL FINALLY SCOUR OUT ANY
LINGERING WEDGE AS SURFACE HIGH PRESSURE REBUILDS FROM THE SOUTHERN
PLAINS AND NORTHERN GULF COAST. MODELS THEN BEGIN TO DIFFER WITH THE
PLACEMENT OF THE HIGH INTO EARLY NEXT WEEK...WITH THE GFS SHIFTING IT
INTO ATLANTIC OVER THE WEEKEND WHILE A COASTAL TROUGH FORMS JUST
OFFSHORE...WHEREAS THE ECMWF IS MUCH SLOWER IN TRANSITIONING IT
OFFSHORE. EITHER WAY...OTHER THAN SOME SHOWERS WITH THE PASSING
UPPER TROUGH THURSDAY NIGHT PREFER TO MAINTAIN A RAIN-FREE FORECAST
THROUGH THE WEEKEND. THE POTENTIAL FOR SOME SHOWERS TO AFFECT THE
AREA COULD INCREASE BY EARLY NEXT WEEK. AS FOR TEMPERATURES...THEY
WILL BEGIN MODERATING LATE WEEK...THEN BECOME ABOVE NORMAL THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
SIGNIFICANT FLIGHT RESTRICTIONS ARE POSSIBLE AT BOTH TERMINALS
THROUGH 12Z TUESDAY DUE TO ABUNDANT MOISTURE IN THE LOW LEVELS OF
THE ATMOSPHERE. THE TAF/S INDICATE PREVAILING LIFR CEILINGS...BUT
VISIBILITIES WILL ALSO BE MVFR OR LOWER THROUGH TONIGHT DUE TO FOG
AND/OR RAIN. AS FOR RAIN CHANCES...THEY APPEAR BEST THROUGH EARLY
EVENING...BUT EVEN LATER TONIGHT AREAS OF DRIZZLE ARE EXPECTED.
EXTENDED AVIATION OUTLOOK...HIGH CONFIDENCE IN FLIGHT RESTRICTIONS
THROUGH THURSDAY DUE TO A SURFACE WEDGE OF HIGH PRESSURE KEEPING
ABUNDANT LOW-LEVEL MOISTURE IN PLACE OVER THE TERMINALS. CEILINGS
AND TO A LESSER EXTENT VISIBILITIES COULD LOWER TO LIFR LEVELS AT
TIMES...MAINLY AT NIGHT. LIGHT RAIN AND DRIZZLE WILL ALSO IMPACT THE
TERMINALS AT TIMES THROUGH THURSDAY. VFR CONDITIONS SHOULD RETURN
FRIDAY.
&&
.MARINE...
TODAY AND TONIGHT...A WARM FRONT NEAR THE COAST WILL WEAKEN AND
SHIFT OFFSHORE TONIGHT ALLOWING FOR VEERING WINDS TO THE SOUTH
TODAY AND NORTHWEST TONIGHT. SPEEDS WILL MAINLY BE 10-15 KT OR
LESS WITH SOME HIGHER GUSTS OVER THE EASTERN PORTIONS OF THE
CHARLESTON COUNTY WATERS AND OFFSHORE GEORGIA WATERS. SEAS WILL
REMAIN ELEVATED ENOUGH TO MAINTAIN A SMALL CRAFT ADVISORY FOR THE
CHARLESTON COUNTY WATERS UNTIL LATE AFTERNOON AND THE GEORGIA
OFFSHORE WATERS THROUGH THE PERIOD. IN ADDITION...THE WARM AND
HUMID AIR MASS OVER THE COOL NEARSHORE WATERS COULD LEAD TO SOME
DENSE SEA FOG.
TUESDAY...NORTHEAST WINDS WILL GRADUALLY INCREASE AS THE PRESSURE
GRADIENT STEADILY INTENSIFIES IN RESPONSE TO A DEVELOPING INLAND
WEDGE. NORTH WINDS OF 10-15 KT IN THE MORNING...WILL BECOMING
NORTHEAST 15-20 KT IN THE AFTERNOON. SPEEDS WILL FURTHER INCREASE TO
20-25 KT OVER THE GEORGIA OFFSHORE WATERS AND THE CHARLESTON COUNTY
WATERS DURING THE EVENING HOURS. A FAVORABLE NORTHEAST FETCH WILL
SUPPORT BUILDING SEAS...WHICH SHOULD REACH 5-7 FT ACROSS THE
CHARLESTON COUNTY AND OUTER GEORGIA WATERS...AND 4-6 FT ACROSS MOST
OF THE OTHER NEAR SHORE ZONES BY LATE TUESDAY NIGHT.
WEDNESDAY...SEAS WILL BEGIN TO SUBSIDE AS WINDS TURN NORTH AND
DIMINISH SOME AS LOW PRESSURE DEVELOPS WELL TO THE SOUTH AND
SOUTHEAST OF THE LOCAL MARINE AREA. WINDS WILL BE ELEVATED TO START
THE DAY...BUT SHOULD DIMINISH TO AROUND 15 KT OR LESS WEDNESDAY
NIGHT. SEAS WILL SUBSIDE TO 3-4 FT IN THE NEARSHORE WATERS AND 4-6
FT IN THE OFFSHORE WATERS WEDNESDAY NIGHT.
THURSDAY THROUGH FRIDAY NIGHT...NORTH TO NORTHWEST WINDS WILL
PREVAIL AND REMAIN SOMEWHAT ELEVATED IN THE 15-20 KT RANGE AT TIMES.
SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH THE
PERIOD...EXCEPT OVER THE GEORGIA OFFSHORE WATERS WHERE SEAS WILL
REMAIN AT OR ABOVE 6 FT.
SATURDAY...WINDS SHOULD SHIFT A BIT MORE ONSHORE WITH SPEEDS
LOWERING TO 15 KT OR LESS. SEAS SHOULD ALSO FINALLY SUBSIDE BELOW
SMALL CRAFT ADVISORY LEVELS IN THE OUTER GEORGIA WATERS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ350.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
549 AM EST MON JAN 12 2015
.SYNOPSIS...
A PRESSURE TROUGH WILL REMAIN ALONG THE COAST TODAY. A COLD FRONT
APPROACHING FROM THE NORTHWEST WILL MOVE THROUGH THE FORECAST AREA
TONIGHT. THE FRONT WILL BE NEAR THE COAST TUESDAY THROUGH TUESDAY
NIGHT. THE FRONT WILL SHIFT FARTHER OFFSHORE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
TODAY...UPPER-LEVEL LIFT AHEAD OF THE MID-LEVEL SHORTWAVE TROUGH
AND ISENTROPIC UPGLIDE OVER THE WEDGE RIDGE SUPPORT RAIN TODAY.
THE 00Z SPC WRF DISPLAYED MUCH OF THE MORE SIGNIFICANT RAIN MAINLY
EAST OF THE FORECAST AREA FOR MUCH OF THE DAY. THE 07Z HRRR
DISPLAYED CONSIDERABLE COVERAGE DURING MOST OF THE DAY. WE LEANED
TOWARD THE HRRR BASED ON THE SHORTWAVE TROUGH EVIDENT ON WATER
VAPOR IMAGERY UPSTREAM ALTHOUGH THIS FEATURE MAY HAVE LIMITED
MOISTURE WHEN IT AFFECTS THE FORECAST AREA BECAUSE OF PREVIOUS
CONVECTION. EVEN IF THE WRF VERIFIES BELIEVE ISENTROPIC LIFT WILL
RESULT IN AT LEAST OCCASIONAL LIGHT RAIN OR DRIZZLE FOR MUCH OF TODAY.
THERE MAY ALSO BE A FEW ELEVATED THUNDERSTORMS BECAUSE OF THE
INCREASE IN MOISTURE AND INSTABILITY THAT HAS OCCURRED AHEAD OF
THE SHORTWAVE TROUGH AND THE STRONG LOW-LEVEL JET ABOVE THE STRONG
SURFACE-BASED INVERSION. THE NAM KEEPS THE TOTALS TOTAL NEAR 50
THROUGH TODAY. SOME LOCATIONS HAVE ALREADY EXPERIENCED A
THUNDERSTORM EARLY THIS MORNING. AN AVERAGE OF THE GFS AND NAM
SUPPORTS RAINFALL TODAY GENERALLY AROUND .2 OF AN INCH IN THE
WEST TO .8 OF AN INCH IN THE EAST. LOCALLY HIGHER AMOUNTS MAY
OCCUR IN HEAVIER SHOWERS OR THUNDERSTORMS. THE NAM SURFACE-BASED
LI PATTERN SUGGESTS THE WEDGE PATTERN WILL HOLD THROUGH TODAY. WE
USED THE COOLER MET MOS TEMPERATURES.
TONIGHT...MOISTURE SHOULD BE MORE SHALLOW BEHIND THE MID-LEVEL
SHORTWAVE TROUGH. CONVERGENCE ASSOCIATED WITH THE COLD FRONT
MOVING INTO THE AREA MAY HELP SUPPORT RAIN BUT THE CHANCE SHOULD
BE LIMITED BECAUSE OF SHALLOW MOISTURE. WE USED THE MET MOS POPS
WHICH WERE AROUND 30 PERCENT. THE MAV AND ECMWF MOS POPS WERE
LOWER. FOG MAY BE AN ISSUE WITH HIGH LOW-LEVEL MOISTURE AND THE
DRYING ALOFT. SOME WIND BEHIND THE COLD FRONT MAY HELP DIMINISH
SOME OF THE FOG LATER TONIGHT. CLOUDINESS AND MIXING LATE SHOULD
HELP HOLD UP TEMPERATURES. USED THE GUIDANCE CONSENSUS WITH LOWS
NEAR 40 NORTH TO THE MIDDLE 40S SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
COOLING WILL OCCUR BEHIND THE COLD FRONT TUESDAY. ISENTROPIC LIFT
PLUS ANOTHER IN THE SERIES OF MID-LEVEL SHORTWAVE TROUGHS IN THE
ACTIVE SOUTHERN STREAM MAY BRING RAIN. THE GUIDANCE CONSENSUS
SUPPORTS POPS OF 40 TO 50 PERCENT. THE TEMPERATURE GUIDANCE IS
LIKELY TOO WARM BUT STILL BELIEVE IT WILL BE WARM ENOUGH FOR ALL
LIQUID PRECIPITATION. THE NAM AND GFS ARE IN AGREEMENT KEEPING
SURFACE WET-BULB TEMPERATURES ABOVE FREEZING THROUGH THE DAY.
THE PRECIPITATION MAY CONTINUE TUESDAY NIGHT INTO EARLY WEDNESDAY
ASSOCIATED WITH CONTINUED WEAK ISENTROPIC LIFT AND ANOTHER IN THE
SERIES OF MID-LEVEL SHORTWAVE TROUGHS. FURTHER COOLING WILL
OCCUR TUESDAY NIGHT AND BOTH THE GFS AND NAM INDICATE WET-BULB
TEMPERATURES FALLING BELOW FREEZING IN THE NORTH PART OF THE
FORECAST AREA. THIS AREA INCLUDES THE COUNTIES OF NEWBERRY...
FAIRFIELD...KERSHAW...LANCASTER...AND CHESTERFIELD. THE MODELS ARE
IN AGREEMENT INDICATING SHALLOW MOISTURE AND WEAK LIFT WITH JUST
LIGHT PRECIPITATION AMOUNTS OF LESS THAN ONE-TENTH OF AN INCH. WE
CONTINUED THE FORECAST OF A CHANCE OF LIGHT FREEZING RAIN OR
DRIZZLE IN THE NORTH PART FOR LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING CLOSE TO THE TIMING OF THE NAM AND GFS FREEZING WET-BULB
TEMPERATURES AND THE SREF GUIDANCE.
LATER WEDNESDAY MORNING THE PRECIPITATION CHANCE WILL LIKELY
FURTHER DIMINISH. THE MODELS HAVE SHOWN SOME CONSISTENCY WITH THE
AREA UNDER MID-LEVEL SHORTWAVE RIDGING WITH LITTLE OR NO
ISENTROPIC LIFT DURING MUCH OF THE DAY. HOWEVER...MODEL TIME SECTIONS
SHOW HIGH LOW-LEVEL MOISTURE CONTINUING ACROSS THE AREA WEDNESDAY
AND WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE SOUTHERN STREAM WILL LIKELY REMAIN ACTIVE THURSDAY. THE ECMWF
WAS MOVE PRONOUNCED MOVING DEEPER MOISTURE INTO THE AREA. THE GFS
MOS HAD A POP NEAR 20 PERCENT AT COLUMBIA COMPARED TO THE ECMWF
POP OF ABOUT 60 PERCENT. WE FORECASTED CHANCE POPS. ONCE AGAIN...
PRECIPITATION TYPE WILL BE A CONCERN BUT FOR NOW BASED ON THE
LATEST GFS THERE APPEARS TO BE JUST ENOUGH WARMING IN THE LOWEST
LAYERS FOR ALL LIQUID PRECIPITATION. THE GFS AND ECMWF DISPLAY DRY
RIDGING DOMINATING SATURDAY. THE ECMWF MAINTAINED DRY CONDITIONS
SUNDAY...BUT THE GFS HAD SOME INCREASE IN MOISTURE. STILL...THE
GFS MOS HAD POPS OF ONLY AROUND 20 PERCENT SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
IFR/POSSIBLE LIFR RESTRICTIONS EXPECTED FOR THE TAF SITES FOR MUCH
OF THE PERIOD.
REGIONAL RADAR CONTINUES TO SHOW AREAS OF LIGHT TO MODERATE RAIN
ACROSS THE SOUTHEAST. CIGS HAVE DROPPED INTO IFR/LIFR LEVELS AND DO
NOT EXPECT MUCH IN THE WAY OF IMPROVEMENT THROUGH THE TAF PERIOD.
STRONG INVERSION EARLY THIS MORNING WITH LIGHT WINDS AT THE SURFACE
BUT WITH S WINDS AROUND 20 TO 25 KTS AT 2KFT. LIGHTNING DETECTION
PROGRAM SHOWING ISOLATED LIGHTNING IN THE AREA THAT MAY BRIEFLY
AFFECT THE TAF SITES OVER THE NEXT FEW HOURS...BUT NOT ENOUGH
CONFIDENCE TO MENTION TSRA IN THE TAFS AT THIS TIME. WINDS THROUGH
THE PERIOD WILL BE GENERALLY NORTHEASTERLY AT 6 KNOTS OR LESS...BUT
MAY GO LIGHT AND VARIABLE AT TIMES.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE TUESDAY THROUGH
FRIDAY AS SERIES OF SYSTEMS CROSS THE REGION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
607 AM CST MON JAN 12 2015
.SHORT TERM...
312 AM CST
THROUGH TONIGHT...
THE MAIN FOCUS WILL BE WORKING PRECIP OUT OF THE AREA THIS
MORNING FOLLOWED BY LAKE EFFECT SNOW SHOWER POTENTIAL THIS AFTERNOON
THROUGH TONIGHT. WATER VAPOR IMAGERY SHOWS A PRIMARY UPPER LEVEL
TROUGH AXIS MOVING SOUTHEAST ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY. ANOTHER SMALLER SCALE UPPER TROUGH IS MOVING EAST INTO
NORTHERN ILLINOIS. AT THE SURFACE...A COLD FRONT IS MOVING ACROSS
THE CWA. RADAR MOSAIC SHOWS PRECIPITATION STEADILY MOVING
NORTHEASTWARD WITH THE BACK EDGE MAKING GRADUAL SOUTHEAST PROGRESS.
SOUTHEAST PROGRESS WILL LIKELY INCREASE IN SPEED THROUGH THE MORNING
AS EACH OF THE UPPER TROUGHS CONTINUE EAST AND SOUTHEAST. IT ALSO
APPEARS THAT THE MAIN FRONTOGENETICAL BAND ON THE NORTHERN EDGE WILL
BE WEAKENING OVER THE NEXT FEW HOURS ALLOWING PRECIP TO DECREASE IN
COVERAGE ACROSS CENTRAL AREAS. MOST OF THE SOUTHERN CWA HAS CHANGED
OVER TO SNOW BUT SOUTHERN PORTIONS OF THE ADVISORY AREA ARE PROBABLY
STILL SEEING A MIX. WILL HOLD ONTO THE ADVISORY FOR NOW GIVEN THAT
PRECIP WILL STILL BE FALLING FOR A FEW HOURS BUT AM THINKING IT MAY
BE ABLE TO BE CANCELLED A LITTLE EARLY. THE PASSAGE OF THE INITIAL
UPPER TROUGH AND SURFACE COLD FRONT WILL ALLOW COLDER AIR TO SPREAD
ACROSS THE AREA THROUGH THE AFTERNOON...WITH THE MAIN TROUGH AXIS
BRINGING A BETTER PUSH LATE IN THE DAY. WILL LIKELY SEE A SITUATION
WHERE MANY AREAS SEE THEIR DAYTIME HIGH TEMP THIS
MORNING...ESPECIALLY SOUTH AND EAST...WITH NORTHWEST AREAS POSSIBLY
WARMING A FEW DEGREES THIS AFTERNOON. EXPECT AFTERNOON TEMPERATURES
IN THE LOWER TEENS NORTHWEST TO AROUND 20 SOUTHEAST.
LAKE EFFECT AND TEMPS TONIGHT...WITH STRONG HIGH PRESSURE MOVING
INTO THE UPPER MISSISSIPPI RIVER VALLEY...WINDS WILL TURN NORTHERLY
BEHIND THE PASSING COLD FRONT. THIS WILL SET UP A LONG FETCH DOWN
LAKE MICHIGAN LEADING TO CONVERGENCE AS THERMAL PARAMETERS BECOME
MORE FAVORABLE FOR LAKE EFFECT. LAKE TO H85 DELTA T`S INCREASE TO
-17 TO -18C LATE THIS AFTERNOON. EQUILIBRIUM LEVELS PEAK AROUND 6500
FT LATE THIS AFTERNOON AND EARLY THIS EVENING THEN LOWER TO AROUND
4000 FT INTO THE EARLY OVERNIGHT. WINDS WILL START OUT DUE NORTH
THEN STEADILY SHIFT NORTHEAST THROUGH THE EVENING THEN EAST
OVERNIGHT. HAVE SEEN LAKE EFFECT SNOW SHOWERS SET UP WITH LESS
FAVORABLE PARAMETERS IN LONG FETCH SITUATIONS THIS SEASON BUT THE
STEADY SHIFT TO NORTHEAST WINDS AND SHORTENING OF THE FETCH WILL
LIKELY LIMIT THE DURATION. COVERAGE WILL ALSO BE SOMEWHAT UNCERTAIN.
TIMING WILL BE A BIT TRICKY BUT EXPECT THAT AT LEAST A LOOSELY
ORGANIZED BAND OR BANDS TO DEVELOP LATER THIS MORNING ACROSS THE
EASTERN PART OF THE LAKE WITH BETTER ORGANIZATION INTO THE
AFTERNOON. PORTER COUNTY MAY BE AFFECTED BY LATE MORNING WITH
INCREASING CHANCES THROUGH THE AFTERNOON AS CONVERGENCE FOCUSES AND
THERMAL PARAMETERS IMPROVE. LAKE COUNTY INDIANA WILL BE FAVORED BY
EVENING IF NOT A LITTLE SOONER AS WINDS START TO COME AROUND. THE
BAND SHOULD STEADILY SHIFT WESTWARD THROUGH THE EVENING AFFECTING
EASTERN COOK COUNTY EARLY TO MID EVENING. THE FETCH SHORTENS BEYOND
THAT SO COVERAGE AND INTENSITY SHOULD QUICKLY DROP OFF. A POTENTIAL
WILD CARD WOULD BE IF A MESO LOW CAN DEVELOP WHICH COULD ACT TO
PROLONG ACTIVITY SOMEWHAT BUT INVERSION HEIGHTS WILL BE FALLING AS
HIGH PRESSURE BUILDS IN SO ACTIVITY WOULD LIKELY BE MINIMAL
OVERNIGHT IF THIS DID OCCUR. WILL GO AHEAD AND INCREASE POPS TO LOW
END LIKELY LATE THIS AFTERNOON AND EARLY THIS EVENING...PRIMARILY
ALONG THE COOK/LAKE INDIANA BORDER AND MUCH OF NORTHERN LAKE
COUNTY...WITH HIGH CHANCE FOR SURROUNDING AREAS. WITH SOME
UNCERTAINTY ABOUT COVERAGE AND INTENSITY AM HESITANT TO RAISE BEYOND
THAT AT THE MOMENT. GIVEN THE UNCERTAINTY IN COVERAGE CONFIDENCE IN
SNOW AMOUNTS IS LIMITED BUT THE PROGRESSIVE EAST TO WEST MOVEMENT OF
ANY ACTIVITY AND LIMITED INVERSION HEIGHTS WOULD LIKELY LIMIT
ACCUMULATIONS. WINDS WILL WEAKEN OVERNIGHT BUT MAY NOT COMPLETELY
DROP OFF...BUT WESTERN AREAS WILL LIKELY FALL TO AROUND 0 WITH AREAS
TO THE EAST SEEING TEMPS IN THE SINGLE DIGITS...WITH WARMER READINGS
IN THE IMMEDIATE CHICAGO METRO AND POINTS NORTH THANKS TO FLOW OFF
THE LAKE.
MDB
&&
.LONG TERM...
312 AM CST
TUESDAY THROUGH SUNDAY...
TUESDAY THROUGH THURSDAY...HIGH PRESSURE WILL BE STRETCHED ACROSS
THE GREAT LAKES AND ST. LAWRENCE VALLEY BY TUESDAY. A MUCH FLATTER
UPPER FLOW WILL BE IN PLACE ALLOWING MID LEVEL TEMPS TO MODIFY BUT
WINDS WILL BE LIGHT LIMITING MIXING. WILL CONTINUE WITH HIGHS IN THE
MID TO UPPER TEENS. THE CENTER OF THE HIGH WILL SHIFT EAST TUESDAY
NIGHT BUT A RIDGE AXIS WILL REMAIN ACROSS THE AREA ALLOWING FOR A
DECOUPLING OF WINDS SETTING UP STRONG RADIATIONAL COOLING POTENTIAL.
AN UPPER LEVEL TROUGH WILL BE MOVING ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY AND MAY SPREAD HIGHER LEVEL CLOUD COVER IN LATE WHICH
MAY LIMIT MAXIMUM COOLING POTENTIAL. AT THIS POINT WILL STICK WITH
LOWS MOSTLY IN THE SINGLE DIGITS BELOW ZERO WITH A STEADY OR WARMING
TREND OVERNIGHT POSSIBLE. A SLOWER PROGRESSION OF THE UPPER TROUGH
TO THE NORTHWEST COULD LEAD TO SLIGHTLY COLDER TEMPS OVERNIGHT WITH
A LONGER COOLING PERIOD. THE UPPER TROUGH PASSES WEDNESDAY AND WILL
PROBABLY ONLY RESULT IN AN INCREASE IN CLOUD COVER GIVEN THE
RESIDUAL LOW LEVEL DRY AIR FROM THE DEPARTING SURFACE HIGH. MILDER
LOW/MID LEVEL TEMPS SHOULD ALLOW FOR A DECENT RECOVERY OF TEMPS INTO
THE UPPER TEENS TO NEAR 20. ANOTHER SYSTEM WILL MOVE ACROSS SOUTHERN
CANADA THURSDAY BRINGING ADDITIONAL MODIFICATION OF LOW AND MID
LEVEL TEMPS WITH A STEADIER SOUTHWEST LOW LEVEL FLOW SUPPORTING MID
20S FOR HIGHS. PRECIP FROM THIS SYSTEM LOOKS TO STAY NORTH BUT HAVE
SEEN THESE NORTHERN SYSTEMS HAVE A TENDENCY TO TRACK FURTHER SOUTH
IN RECENT WEEKS SO WILL NEED TO WATCH THAT POTENTIAL IN THE COMING
DAYS.
FRIDAY THROUGH SUNDAY...WESTERN UPPER RIDGING WILL SPREAD
EASTWARD BUT DE-AMPLIFY LATE IN THE WEEK. THIS WILL EVOLVE INTO A
MORE ZONAL FLOW PATTERN INTO THE WEEKEND BUT THE NORTHERN PORTION
OF THE FLOW WILL BE ACTIVE. THE MAIN BAROCLINIC ZONE LOOKS TO
REMAIN TO THE NORTH KEEPING THE LOCAL AREA ON THE SOUTHERN FRINGE
OF ANY SYSTEMS INTO THE WEEKEND. MEDIUM RANGE GUIDANCE IS NOT IN
GREAT AGREEMENT BUT DOES POINT TOWARDS SOME AMPLIFICATION OF THE
FLOW EARLY NEXT WEEK. A MILDER PERIOD WILL RESULT FROM THE MORE
ZONAL PATTERN WITH HIGHS IN THE 30S FRIDAY THROUGH SUNDAY.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* GUSTY NORTH WINDS WITH MAX GUSTS ARND 20 KT FROM MID MORNING
THROUGH THE AFTERNOON.
* WINDS BECOME NORTHEAST THIS EVENING.
* MVFR CIGS EXPECTED THIS EVENING AND OVERNIGHT WITH A CHANCE OF
LAKE EFFECT SNOW THIS EVENING.
JEE
//DISCUSSION...UPDATED 12Z...
A COLD FRONT HAS MOVED THROUGH ALL OF THE TERMINALS WITH NORTH
WINDS ARND 10 KT. CIGS HAVE ALSO COME UP TO VFR AND WILL REMAIN
VFR THROUGH THIS AFTN FOR ALL SITES EXCEPT GYY. WINDS START
GUSTING BY MID MORNING WITH MAX GUSTS ARND 20 KT. A BAND OF LAKE
EFFECT SNOW IS EXPECTED TO DEVELOP OVER NORTHWEST INDIANA THIS
AFTERNOON AND THEN SWING WEST AS WINDS TURN NORTHEAST. GARY HAS
THE BEST CHANCE AT SEEING SNOW. THINKING VSBY WILL BE MVFR TO IFR
IN THE SNOW BUT HAVE MEDIUM-LOW CONFIDENCE IN VSBYS SO ONLY WENT
WITH MVFR IN THE TAF. MVFR CIGS ARE EXPECTED REGARDLESS IF IT
SNOWS OR NOT.
STILL HAVE MEDIUM CONFIDENCE ABOUT SNOW MAKING IT TO MDW AND ORD
SO KEPT A PROB30 IN THE TAF. MVFR CIGS ARE EXPECTED REGARDLESS OF
SNOWFALL AT MDW AND ORD AS WELL. THINKING THE MVFR CIGS WILL NOT
REACH DPA. GUSTS SUBSIDE IN THE EVENING AND WINDS TURN NORTHEAST
THIS EVENING AND THEN EAST BY TUESDAY MORNING.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN LAKE EFFECT SNOW OCCURRING THIS
EVENING...HIGH CONFIDENCE IN MVFR CIGS.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
JEE
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. LIGHT AND VARIABLE WINDS BECOMING SOUTHWEST.
WEDNESDAY AND THURSDAY...VFR. WEST TO SOUTHWEST WINDS.
FRIDAY AND SATURDAY...VFR. SOUTHWEST WINDS.
SUNDAY...SLIGHT CHANCE OF RAIN OVERNIGHT. EAST WINDS.
JEE
&&
.MARINE...
217 AM CST
SMALL CRAFT ADVISORY...ONLY CHANGE MADE TO THE SMALL CRAFT IS
EXTENDING IT TO MID TUESDAY MORNING ALONG THE IL NSH WATERS. ICE
COVERAGE WAS NOT SOLID SO THINKING HIGH WAVES FROM THE ONSHORE FLOW
WILL REACH THE IL NSH WATERS. THE WAVES WILL BE HAZARDOUS TO SMALL
CRAFT SO EXTENDED THE IL SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
WAVES.
A WEAK SURFACE TROUGH IS OVER THE LAKE EARLY THIS MORNING WITH A
COLD FRONT STRETCHING FROM NORTH CENTRAL MICHIGAN THROUGH WAUKEGAN
IL. THE COLD FRONT WILL CONTINUE SOUTHEAST WITH NORTHWEST WINDS
BECOMING NORTH AND INCREASING TO 30 KT BY LATE THIS MORNING. WINDS
DIMINISH AND VARY FROM NORTH TO NORTHEAST THIS EVENING AND BECOME
MORE CHAOTIC AS HIGH PRESSURE MOVES OVERHEAD TONIGHT. BY TUESDAY
MORNING EXPECTING EAST WINDS OVER THE SOUTHERN HALF OF THE LAKE AND
NORTHWEST WINDS OVER THE NORTHERN HALF. THE HIGH SLOWLY SHIFTS SOUTH
ALLOWING WINDS TO BECOME SOUTHWEST ACROSS THE LAKE TUESDAY NIGHT.
THE PRESSURE GRADIENT TIGHTENS OVER THE NORTHERN END OF THE LAKE
TOMORROW NIGHT AND WINDS INCREASE TO 15 TO 25 KT. WINDS DIMINISH
AND BECOME WEST WEDNESDAY.
ANOTHER LOW PASSES OVER ONTARIO WEDNESDAY NIGHT INTO THURSDAY WITH
SOUTHWEST TO WEST WINDS INCREASING TO 15 TO 25 KT WEDNESDAY NIGHT.
HIGH PRESSURE FOLLOWS THE LOW FRIDAY ALLOWING WEST WINDS TO DIMINISH
AND THEN BECOME SOUTH BEHIND THE HIGH LATE FRIDAY. THE NEXT LOW
MOVES OVER SOUTHERN MANITOBA FRIDAY NIGHT AND INCREASES THE PRESSURE
GRADIENT OVER THE LAKE. SOUTHWEST WINDS INCREASE TO 15 TO 25 KT AND
THEN DIMINISH SATURDAY NIGHT AS THE LOW MOVES OVER QUEBEC.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ033-ILZ039 UNTIL 9 AM MONDAY.
IN...WINTER WEATHER ADVISORY...INZ010-INZ011-INZ019 UNTIL 9 AM MONDAY.
LM...SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 AM TUESDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 4 AM TUESDAY.
&&
$$
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
[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
556 AM CST Mon Jan 12 2015
.SHORT TERM...(Today)
ISSUED AT 341 AM CST MON JAN 12 2015
No changes planned to the winter weather advisory with the 4 am
package. We will just clear out the western counties as precip ends
and conditions warrant as the morning progresses. The back edge of
the precip is becoming more diffuse, but another trailing band of
snow is still approaching from SE Iowa and N Missouri. Forecast
soundings show we will be losing our ice crystals aloft this
morning, which could cause the light snow to change to freezing
drizzle. Over the next 3-5 hours, we could see a few tenths of an
inch of snow accumulate from the band of snow from Jacksonville to
Bloomington progressing east. The dual pol radar images show the
precip change to all snow clearly, with the leading edge of snow
from Springfield to northwest Champaign county at 09z/3am. Just
ahead of the change-over from rain to snow, there have been reports
of freezing rain and sleet from Champaign to Taylorville, so some
light glazing will still be possible before the rain changes to
completely to snow.
Areas southeast of I-70 could see temps hold just above freezing
until sunrise, and then remain hovering just above freezing until
later morning behind the cold front. So precip would just change
from rain to snow. The main freezing conditions in that area would
be due to the frozen ground freezing rain on untreated surfaces.
Falling temps are expected this afternoon across the board, as NW
winds of 15 gusting to 25 mph usher our next wave of unseasonably
cold air. The HRRR is advertising a rapid clearing of clouds this
morning from NW to SE, which seems a little ahead of satellite
trends. We will delay clearing until later morning in the west, then
progress to all but the far southeast this afternoon.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 341 AM CST MON JAN 12 2015
Tonight the weather quiets down again with high pressure building
back into the Midwest and controls the weather through the week.
Roughly mid week as a synoptic wave digs into the desert SW, flow
over the eastern half of the country moves from more zonal to a more
amplified pattern. Northwesterly flow over the region will move a
short wave through the region as well... and although the models are
currently dry under the surface ridge...will need to watch the
strength of the wave and its persistence for some flurry potential
Wednesday afternoon/evening. Other than that...temps this week
starting out below normal but slowly warming through the end of the
week as more southwesterly flow at the sfc maintains WAA through the
forecast. Next system is starting to have some issues with
consistency for the weekend. Prev GFS originated the system out of
the SW, a result of the bigger wave from earlier in the week. The
most recent ECMWF is weaker with the southern stream/wave...and
instead, develops the sfc system from a shortwave moving across the
nrn tier of the country. With perpetual waa ahead of the system,
have maintained the precip for Sun night and into Monday for rain.
But, with the details so divergent at this point, keeping the
forecast conservative. A more northerly stream system may end up
with more of a precip type decision as the time approaches. A
little too early to call and expect some variability.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 556 AM CST MON JAN 12 2015
The change of precip from rain to snow has reached all terminal
sites, with light snow continuing at CMI through 14z or so. SPI
and BMI will see snow diminish through 13z. LIFR cigs and MVFR fog
will linger at BMI and near CMI for only an hour or two before
dry air aloft mixes down and conditions improve to MVFR and then
VFR by mid-day. SPI and DEC will see clouds lift from IFR to VFR
by late morning as well, with PIA already seeing VFR conditions.
VFR conditions will then continue for the remainder of the
forecast period. Surface winds have become north behind the cold
front, and will increase to 13-16kt sustained and gusts to around
23-24kt, especially during the afternoon. Wind gusts will diminish
after 00z/6pm today, but speeds will linger between 10 to 15 kts thru 06z
before diminishing to less than 10kt.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY until 9 AM CST this morning FOR
ILZ042>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Shimon
LONG TERM...HJS
AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
513 AM CST MON JAN 12 2015
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CST MON JAN 12 2015
SURFACE HIGH PRESSURE ACROSS THE DAKOTAS AND MONTANA THIS
MORNING WILL CONTINUE TO SLIDE SOUTH TODAY, WEAKENING THE SURFACE
WIND FIELD WITH TIME AND CONTINUING TO PROVIDE WEAKENING BOUNDARY
LAYER COLD ADVECTION. THE SNOW OVER EASTERN COLORADO WILL TAPER
TO AND END THIS MORNING WHILE THE VARIABLE AREAS OF STRATUS OVER
THE AREA WILL BE THE MAIN FOCUS FOR THE VERY NEAR TERM.
TEMPERATURES WILL NOT EXCEED THE 20S TODAY WITH THE COLD AIRMASS
MOVING INTO THE REGION. THE 3 KM RESOLUTION RAPID REFRESH AND 13
KM RAPID REFRESH HAVE BEEN THE DOMINANT MODELS THE LAST COUPLE OF
DAYS, AND THIS MAY CONTINUE TO BE THE TREND TODAY AS WELL AND WERE
FOLLOWED FOR THE REST OF TODAY. CLEARING SKIES ARE NOT LIKELY
BASED ON THE NAM`S RELATIVE HUMIDITY FIELDS TONIGHT. SURFACE WINDS
SHOULD BECOME MORE EASTERLY WITH TIME INTO THE EVENING. LARGE
UNCERTAINTY EXISTS WITH RESPECT TO OVERNIGHT TEMPERATURES AS
CLOUD COVER MAY PLAY A LARGE ROLE BETWEEN LOW SINGLE DIGITS AND
TEENS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 353 AM CST MON JAN 12 2015
NAM AND GFS CONTINUES TO INDICATE IMPROVING ISENTROPIC LIFT ON
TUESDAY ACROSS WESTERN KANSAS IN THE 800MB TO 600MB LEVEL. THIS
AREA OF LIFT AND MOISTURE IS SHIFTED FROM SOUTHWEST KANSAS AT 12Z
TUESDAY TO NORTH CENTRAL AND CENTRAL KANSAS BY LATE DAY AS AN
UPPER LEVEL TROUGH APPROACHES THE CENTRAL HIGH PLAINS FROM THE
NORTHWEST. BELOW THE 800MB LEVEL DRIER AIR IS FORECAST TO BE
PRESENT WHEN COMPARING THE NEW ,00Z MONDAY, NAM/GFS MODELS WITH
PREVIOUS MODEL RUNS. BASED ON THIS THE SNOW CHANCES FOR TUESDAY
CURRENTLY APPEAR LESS FAVORABLE AND THE ONSET, IF IT DOES
DEVELOP, WILL BE LATER THAN WHAT WAS ANTICIPATED YESTERDAY. SINCE
CONFIDENCE IS NOT HIGH ENOUGH TO TOTALLY REMOVE PRECIPITATION
CHANCES LATE DAY WILL THEREFORE CONTINUE WITH SLIGHT CHANCE FOR
LIGHT SNOW BUT FOLLOW THE PREVIOUS FORECAST IN LOWERING THE
CHANCES FOR THIS TO OCCUR.
THE BETTER OPPORTUNITY FOR PRECIPITATION STILL APPEARS TO BE
TUESDAY NIGHT AS THE UPPER LEVEL TROUGH CROSSES WESTERN KANSAS.
700MB FRONTOGENESIS NOT AS PRONOUNCED AS LAST NIGHT AND THE UPPER
LEVEL WAVE IS MORE PROGRESSIVE. DURATION AND SNOWFALL WILL BE
LOWER THAN PREVIOUSLY THOUGHT, HOWEVER LIGHT SNOW STILL IS
ANTICIPATED AT SOME POINT DURING THE OVERNIGHT HOURS.
THE UPPER LEVEL TROUGH WILL MOVE INTO EASTERN KANSAS DURING THE
DAY ON WEDNESDAY WITH CLEARING SKIES EXPECTED AS SUBSIDENCE
DEVELOPS BEHIND THIS UPPER LEVEL SYSTEM. GIVEN THAT THIS SYSTEM
NOW IS MORE PROGRESSIVE AND LESS SNOWFALL ANTICIPATED WILL RAISE
HIGHS A FEW DEGREES. A WARMING TREND IS THEN EXPECTED THROUGH THE
REST OF THE WORK WEEK AS DOWN SLOPE FLOW IMPROVES AS AN UPPER
RIDGE AXIS MOVES ACROSS THE ROCKIES AND OUT INTO THE WESTERN HIGH
PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 511 AM CST MON JAN 12 2015
BASED ON NAM BUFR SOUNDINGS DRIER AIR BELOW THE 850MB LEVEL WILL
FILTER INTO WESTERN KANSAS LATER THIS MORNING AS AN SURFACE HIGH
RIDGE AXIS BUILDS INTO THE AREA FROM THE NORTH. GIVEN THE LATEST
SURFACE OBSERVATION TRENDS THIS IS A REASONABLE SOLUTION SO WILL
FOLLOW THE LATEST HRRR AND RAISE CEILINGS INTO THE 2000 TO 3000FT
AGL RANGE BETWEEN 13Z AND 15Z MONDAY AT DDC AND GCK. MVFR CEILINGS
WILL THEN IMPROVE INTO THE 3500 TO 5000FT AGL AFTER 18Z. GUSTY
NORTH WINDS WILL DECREASE BY 18Z MONDAY TO AROUND 10 KNOTS, AND
THEN BEGIN TO GRADUALLY VEER TO THE EAST LATE TODAY AND EARLY
TONIGHT AS THE SURFACE RIDGE AXIS MOVES SOUTHEAST ACROSS WESTERN
KANSAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 21 10 28 17 / 0 0 20 40
GCK 23 10 28 17 / 0 10 20 30
EHA 24 14 33 19 / 10 10 20 40
LBL 25 12 31 18 / 0 10 20 40
HYS 21 6 26 15 / 0 0 20 30
P28 25 10 29 19 / 0 0 10 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RUSSELL
LONG TERM...BURGERT
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1026 AM EST MON JAN 12 2015
.UPDATE...
SNOW IS WINDING DOWN ACROSS FAR SE LOWER MI AS THE FGEN BAND PULLS
FURTHER EAST. DRY AIR IS NOW WORKING INTO THE AREA AND WILL
CONTINUE TO DO SO THROUGH THE DAY. DEWPOINTS IN NORTHERN LOWER
HAVE FALLEN TO AROUND 10F AND FURTHER WEST IN WI ARE -5F OR LOWER.
THIS IS THE AIRMASS WITHIN THE STRONG +1040MB HIGH PRESSURE
SYSTEM THAT WILL ADVECT OVER THE AREA NOW THROUGH THE OVERNIGHT.
MINOR ADJUSTMENTS TO POPS TO CLEAR THE LAST OF THE SNOW OUT.
ATTENTION THEN TURNS TO JUST HOW LOW TEMPS GET TONIGHT AND HOW FAR
THE LAKE EFFECT CLOUDS OFF LAKE HURON CAN MAKE IT INLAND.
&&
.AVIATION...ISSUED 600 AM EST MON JAN 12 2015
BY 12Z...SNOW WILL DIMINISH TO FLURRIES AT PTK WHILE FNT AND MBS
REMAIN FREE OF SNOW. THE PASSAGE OF A SECONDARY COLD FRONT LATE THIS
MORNING INTO EARLY AFTERNOON WILL BACK THE WINDS TOWARD THE NNW.
GUSTS WILL INCREASE TO 20 KNOTS THIS AFTERNOON AS ARCTIC AIR FILTERS
IN FROM THE NORTH. UPSTREAM OBS AND MODEL SOUNDINGS SUGGEST THERE
WILL BE A GOOD DEGREE OF VARIABILITY IN CEILING HEIGHTS LATER THIS
MORNING AND AFTERNOON. THE ARCTIC AIR FUNNELING INTO THE AREA WILL
BE SHALLOW WHICH WILL FOSTER THE DEVELOPMENT OF A LOW LEVEL
INVERSION. THIS SUPPORTS HOLDING ONTO HIGH MVFR AND/OR LOW VFR
CEILINGS UNTIL THIS WHEN WHEN DRY AIR ADVECTION PROVIDES A CLEARING
TREND.
FOR DTW...THE SNOW WILL DIMINISH BETWEEN 12Z AND 15Z BEFORE ENDING
BY 16Z. ADDITIONAL ACCUMULATIONS AFTER 12Z SHOULD BE LESS THAN A
HALF INCH.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING BELOW 5000 FEET THIS MORNING AND AFTERNOON. LOW
TONIGHT.
&&
.PREV DISCUSSION...ISSUED 346 AM EST MON JAN 12 2015
SHORT TERM...TODAY AND TONIGHT
AFTER A LULL IN THE SNOW SHORTLY AFTER MIDNIGHT...TRENDS IN THE
RADAR AND SFC OBS ARE SHOWING A REINTENSIFICATION OF SNOWFALL ACROSS
NRN INDIANA INTO SE MI. THIS IS THE RESULT OF A RENEWED
STRENGTHENING OF SOME MID TROPOSPHERIC FRONTAL FORCING /IN THE 800-
700MB LAYER/ AND WILL TARGET LOCALS SOUTH OF A SANDUSKY TO OWOSSO
LINE EARLY THIS MORNING. THE FRONTAL CIRCULATION WILL ADVANCE TO THE
EAST DURING THE COURSE OF THE MORNING AS THE UPPER JET SUPPORT
SLIDES EAST OF THE STATE. THE CURRENT NAM AND SEVERAL HI RES
SOLUTIONS SUGGEST THE FORCING WILL WEAKEN AS IT HEADS EAST OF METRO
DETROIT BETWEEN 12Z AND 15Z THIS MORNING. SNOWFALL INTENSITY WILL
FLUCTUATE DURING THE MORNING AS THE STRENGTH OF THE MID LEVEL LIFT
VARIES. IN LIGHT OF THE FORCING AND PROJECTED NEAR TERM QPF
AMOUNTS...ADDITIONAL SNOWFALL ACCUMS BETWEEN A HALF INCH AND INCH
THROUGH DAYBREAK STILL SEEM REASONABLE. BASED ON REPORTS PRIOR TO
MIDNIGHT...THIS SHOULD LEAD TO TOTAL SNOWFALL SOUTH OF A BAD AXE TO
SAGINAW LINE OF 1 TO 3 INCHES. THE HIGHER TOTALS WILL OCCUR ACROSS
THE NRN DETROIT SUBURBS WHERE FORCING WAS A LITTLE MORE PERSISTENT
OVERNIGHT. THERE IS A SECONDARY REGION OF RADAR RETURNS PUSHING
SOUTH ACROSS NRN LOWER MI...OCCURRING ALONG THE 600-500MB PORTION OF
THE FRONT. THE FORCING IS EXPECTED TO WEAKEN AS IT ENTERS THE
SAGINAW VALLEY AND THUMB EARLY THIS MORNING. UPSTREAM RETURNS
HOWEVER SUPPORT AT LEAST CHANCE POPS ACROSS THE NRN THIRD OF THE
FORECAST AREA THIS MORNING. UNTREATED ROADS WILL BE VERY SLICK THIS
MORNING AS THIS SNOW HAS A HIGH WATER CONTENT. WITH TEMPS IN THE
UPPER 20S...ROAD TREATMENTS SHOULD PROVE HIGHLY EFFECTIVE.
WHILE THE COLD FRONT WILL MOVE EAST OF THE AREA EARLY THIS
MORNING...THE PUSH OF ARCTIC AIR WILL NOT ARRIVE INTO SE MI UNTIL
THIS AFTERNOON UNDER STRENGTHENING NORTHERLY WINDS. THIS WILL
SUPPORT MORNING HIGHS /MID 20S TO LOW 30S/...WITH FALLING TEMPS
DURING THE AFTERNOON. WHILE THE MID LEVEL TROUGH AXIS NOW
APPROACHING LAKE SUPERIOR WILL NOT TRAVERSE SE MI UNTIL THIS
EVENING...LARGE SCALE SUBSIDENCE WITHIN THE DESCENDING BRANCH OF THE
MID TROP FRONT WILL LEAD TO SUBSTANTIAL MID LEVEL DRYING THIS
AFTERNOON. THIS WILL KEEP CONDITIONS PRECIP FREE OUTSIDE OF SOME
LAKE EFFECT SNOW SHOWERS OVER THE THUMB REGION UNDER NORTHERLY FLOW.
THE NAM AND 4KM WRF NMM SHOW A DOMINATE LAKE BAND DEVELOPING OVER
THE SRN LAKE HURON BASIN THIS EVENING. THE COLD AIR ADVECTION WILL
BE SHALLOW...SUPPORTING EQUILIBRIUM LEVELS ONLY TO 5K FT.
HOWEVER...STEEP LOW LEVEL LAPSE RATES WITH TEMPS OF -16 TO -18C NEAR
THE NEAR THE TOP OF THE MIXED LAYER COULD LEAD TO SOME GOOD SNOWFALL
RATES. A GRADUAL BACKING OF THE FLOW TO THE NNE AIDED BY A LAND
BREEZE PUSH OFF ONTARIO MAY BRING THIS BAND INTO THE ERN THUMB AND
PORT HURON. WILL KEEP ANY ACCUMS MINOR ATTM /AN INCH OR TWO IN PORT
HURON/. LAKE STRATO CU SHOULD PUSH INTO PORTIONS OF FLINT AND METRO
DETROIT TONIGHT. NAM AND RUC SOUNDINGS SHOW GOOD SUPERSATURATION
WITH RESPECT TO ICE AROUND -16C. THIS MAY BE SUPPORTIVE OF SOME
FLURRIES/LIGHT SNOW SHOWERS OUT OF THE STRATO CU. REGIONS THAT SEE
THE CLOUDS TONIGHT WILL HAVE MIN TEMPS HOLD IN THE SINGLE
DIGITS...WHILE LOCALS ACROSS THE WRN HALF OF THE FORECAST AREA
SHOULD DECOUPLE ENOUGH TO SUPPORT SUB ZERO MINS.
LONG TERM...TUESDAY THROUGH SUNDAY
STRONG SURFACE HIGH PRESSURE WILL REMAIN SPRAWLED OVER THE GREAT
LAKES TUESDAY AND TUESDAY NIGHT. THIS WILL BRING QUIET WEATHER TO
THE AREA AS LAKE EFFECT POTENTIAL OFF LAKE HURON LOOKS TO DECREASE
BY SUNRISE. THIS WILL OCCUR AS INVERSION HEIGHTS/CONVECTIVE DEPTHS
DECREASE AS THE HIGH SETTLES IN...AND AS WINDS TURN MORE EASTERLY
DECREASING THE FETCH. THE DAY SHOULD START OUT WITH PLENTY OF
STRATUS LOCKED UNDER THE INVERSION STRETCHING FROM THE THUMB DOWN TO
THE DETROIT AREA. THIS LAYER SHOULD MIX OUT LATER IN THE AFTERNOON
HOWEVER PER LATEST FORECAST SOUNDINGS FROM NAM/GFS. UPSTREAM
OBSERVATIONS DEPICT A VERY DRY AND COLD AIRMASS UNDER THE RIDGE OVER
CANADA AND THE NORTHERN PLAINS (CURRENT DEWPOINTS -20 TO -30
F...WITH MAX TEMPS YESTERDAY BETWEEN -5 AND 15 F). THE AIRMASS
SHOULD MODIFY SOME AS IT CROSSES THE STILL UNFROZEN GREAT
LAKES...AND EXPECTING MAX TEMPS TUESDAY TO REACH THE MID TEENS. IT
IS POSSIBLE IF WE GET ENOUGH SUNSHINE WE COULD OVERACHIEVE...BUT
WILL LEAN THE FORECAST ON THE PESSIMISTIC SIDE GIVEN HIGH POTENTIAL
FOR LAKE STRATUS DURING THE EARLY PART OF THE DAY. MINS OVERNIGHT
WILL BECOME VERY COLD AS EXCELLENT RADIATIONAL COOLING CONDITIONS SET
UP UNDER THE RIDGE CENTER...WITH CLEAR SKIES...LIGHT/CALM
WINDS...FRESH SNOW...AND A VERY DRY AIRMASS. CONTINUED TREND FROM
INHERITED FORECAST WITH MIN TEMPS BELOW MOS GUIDANCE...FROM NEAR
ZERO TO ABOUT 7 BELOW.
WEAK UPPER SHORTWAVE WILL CLIP ACROSS MICHIGAN WEDNESDAY AS IT
PIVOTS AROUND THE UPPER VORTEX CENTERED NORTH OF HUDSON BAY. SURFACE
REFLECTION LOOKS VERY WEAK...AND WILL ONLY MAKE A SMALL RIPPLE IN
THE SURFACE HIGH STILL EXTENDING FROM THE CENTRAL PLAINS UP THROUGH
THE OHIO VALLEY. FRONTAL BOUNDARY WILL WASH OUT AS IT CROSSES
MICHIGAN WITH THIS SYSTEM...BUT FORCING LOOKS TOO WEAK TO OVERCOME
VERY DRY AIRMASS THAT WILL PRECEDE IT. THE RIDGE AXIS WILL GET
PUSHED TO OUR SOUTH AND EAST WEDNESDAY NIGHT AND THURSDAY AS ANOTHER
CLIPPER SYSTEM IS GUIDED ACROSS ONTARIO AROUND THE VORTEX NORTH OF
HUDSON BAY. PRECIPITATION ASSOCIATED WITH THIS SYSTEM LOOKS TO
REMAIN WELL TO OUR NORTH.
BY FRIDAY MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH ANOTHER
RIDGE OF SURFACE HIGH PRESSURE ENCOMPASSING THE GREAT LAKES...BUT
DIFFER WITH THE AMPLIFICATION OF THE UPSTREAM PATTERN OVER THE
WESTERN U.S. AND CANADA. THIS RESULTS IN SOME UNCERTAINTY WITH THE
FORECAST AS WE HEAD INTO THE WEEKEND AND EARLY NEXT WEEK AS MODEL
SOLUTIONS DIFFER GREATLY IN TIMING THE ARRIVAL OF GULF OF ALASKA
ENERGY INTO THE GREAT LAKES. 00Z EURO/GEM CURRENTLY HAVE THE
STRONGEST CONSENSUS AT 144 HOURS...BUT RUN TO RUN CONSISTENCY IN THE
EURO HAS NOT BEEN STRONG. BOTH THESE SOLUTIONS TRACK SURFACE LOW
PRESSURE INTO THE GREAT LAKES ON SATURDAY...BUT WITH ENOUGH OF A
NORTHERLY TRACK TO KEEP MOST PRECIPITATION OUT OF SOUTHEAST MICHIGAN
SO THE FORECAST REMAINS DRY. ADDITIONAL ENERGY LOOKS TO
FOLLOW...POSSIBLY SETTING US UP IN A MORE ACTIVE PATTERN FOR EARLY
NEXT WEEK. TEMPERATURES DO LOOK TO MODERATE FRIDAY AND THROUGH THE
WEEKEND AS ARCTIC CLIPPERS STOP DIVING THROUGH THE AREA. EXPECTING
MAX TEMPS TO WARM BACK CLOSER TO FREEZING.
MARINE...
GUSTY WINDS WILL DEVELOP OVER LAKE HURON TODAY IN THE WAKE OF AN
EARLY MORNING COLD FRONT. NORTHWESTERLY WIND GUSTS TO 30 KNOTS WILL
BE POSSIBLE OVER ALL BUT INNER SAGINAW BAY. WAVE HEIGHTS WILL ALSO
INCREASE TO AS HIGH AS 7 FEET OVER ICE FREE AREAS THIS AFTERNOON AND
EARLY TONIGHT AS THE FETCH INCREASES. THE COMBINATION OF GUSTY
WINDS...LARGE WAVES...AND COLD TEMPERATURES WILL ALSO CREATE AREAS
OF HEAVY FREEZING SPRAY OVER CENTRAL AND SOUTHERN LAKE
HURON...ESPECIALLY OVER THE OPEN WATERS AND OFF THE TIP OF THE
THUMB. STRONG HIGH PRESSURE BUILDING INTO THE GREAT LAKES TONIGHT
WILL ALLOW FOR A GRADUAL DECREASE IN WINDS AND WAVES TONIGHT. THE
HIGH WILL THEN BRING VERY LIGHT WINDS AS IT SETTLES OVERHEAD ON
TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST
TUESDAY FOR LHZ363-421-441-462>464.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR LHZ421-441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......DRK
AVIATION.....SC
SHORT TERM...SC
LONG TERM....HLO
MARINE.......HLO
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
636 AM EST MON JAN 12 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST MON JAN 12 2015
WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROF EXTENDING FROM SRN HUDSON
BAY TO MN...AND LATEST RUC ANALYSIS SHOWS 850MB THERMAL TROF WITH
TEMPS OF -20 TO -28C APPROACHING NW LAKE SUPERIOR ATTM. AT THE
SFC...ASSOCIATED COLD FRONT EXTENDS FROM NEAR KIWD E TO NEAR
WHITEFISH PT. DESPITE APPROACHING SHORTWAVE TROF AND FAIRLY DECENT
DEEP LAYER FORCING PER QVECTORS...LES OVER LAKE SUPERIOR HAS NOT
SHOWN MUCH CHANGE IN INTENSITY OVERNIGHT. LACK OF MUCH REFLECTIVITY
AOA 28DBZ SUGGESTS SNOW IS MOSTLY LIGHT TO OCCASIONALLY MDT.
WITH DEEP LAYER FORCING THRU ABOUT MID MORNING AND INCREASING
OVERWATER INSTABILITY...EXPECT SOME UPTICK IN LES OVER THE NEXT
SEVERAL HRS. THIS INCREASE SHOULD BE MORE APPARENT OVER FAR WRN
UPPER MI (GOGEBIC/ONTONAGON COUNTIES) AS SHARPER LOW-LEVEL
CONVERGENCE DEVELOPS THERE FOR A SHORT TIME...AND THEN ALSO OVER
NCNTRL UPPER MI (MARQUETTE/ALGER COUNTIES) WHERE A MORE CONVERGENT
NRLY FLOW DEVELOPS. LONGER FETCH AND DEEPER DGZ WILL ULTIMATELY LEAD
TO GREATEST SNOW ACCUMULATIONS IN NCNTRL UPPER MI...ROUGHLY IN THE
AREA BTWN NEGAUNEE AND MUNISING WHERE SNOW ACCUMULATIONS OF 2-4
INCHES WILL BE PAINTED TODAY. 2-3 INCHES ARE POSSIBLE FROM KIWD TO
THE PORCUPINE MTNS. OTHERWISE...SNOW ACCUMULATIONS ACROSS THE REST
OF THE FCST AREA NEAR LAKE SUPERIOR SHOULD BE ON THE ORDER OF AN
INCH OR TWO TODAY. THIS AFTN...STRONG DEEP LAYER QVECTOR DIVERGENCE
IN THE WAKE OF SHORTWAVE AND CORRESPONDING LOWERING OF INVERSION
COMBINED WITH INCREASINGLY ANTICYCLONIC 925MB FLOW AHEAD OF STRONG
ARCTIC HIGH PRES BUILDING INTO THE PLAINS/UPPER MISSISSIPPI VALLEY
WILL LEAD TO DIMINISHING LES COVERAGE/INTENSITY. BRIEF SHOT OF
ARCTIC AIR WILL LEAD TO A COLDER DAY TODAY. EXPECT HIGHS IN THE 5 TO
15 RANGE...COLDEST W.
CENTER OF ARCTIC HIGH PRES WILL MOVE INTO THE WRN GREAT LAKES
TONIGHT. MODERATING 850MB TEMPS AND BACKING WINDS WILL BRING AN END
TO ANY LINGERING LIGHT LES OVER NW UPPER MI EARLY THIS EVENING. LAST
OF THE LES OVER NCNTRL UPPER MI SHOULD SHIFT OFFSHORE BY 06Z.
CLEARING SKIES/DRY COLUMN AND CALM WIND FOR MUCH OF THE AREA FOR
MOST...IF NOT ALL...OF THE NIGHT WILL LEAD TO EXCELLENT RADIATIONAL
COOLING. FAVORED THE LOWEST GUIDANCE WHICH IS THE GLOBAL GEM BIAS
CORRECTED. AS IT HAS FOR THE LAST FEW DAYS...IT SHOWS MINS AS LOW AS
THE LOW TO MID -20S IN THE INTERIOR W HALF TONIGHT. THIS MATCHES UP
FAIRLY WELL WITH CURRENT UPSTREAM TEMPS ACROSS SRN SASKATCHEWAN/SRN
MANITOBA. WOULD NOT BE SURPRISED TO SEE THE COLDEST OF THE
TRADITIONAL COLD SPOTS BOTTOM OUT AROUND -25F TONIGHT. THE ONLY AREA
THAT MIGHT NOT SEE TEMPS FALL BLO ZERO TONIGHT IS OVER THE TIP OF
THE KEWEENAW.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 456 AM EST MON JAN 12 2015
GENERALLY GOOD AGREEMENT FM THE MODELS IN LARGER SCALE PATTERN
EVOLUTION INTO NEXT WEEKEND AS DEEP TROUGH OVER EASTERN CANADA AND
GREAT LAKES SLOWLY UNRAVELS LEADING TO ZONAL FLOW AND TEMPS NUDGING
TOWARD NORMAL OR EVEN SLIGHTLY ABOVE. THAT IS THE LONG AND SHORT OF
IT...BUT DETAILS ARE MUDDLED AND MAINLY HAVE TO DO WITH SOUTHERN
EXTENT OF SERIES OF SHORTWAVES/SFC TROUGHS LATE THIS WEEK AS THE
PATTERN TRIES TO BECOME MORE ZONAL. STILL LOOKS LIKE A PRETTY GOOD
BET THAT TEMPS WILL EXCEED 30 DEGREES IN SOME PART OF THE CWA
THURSDAY INTO SATURDAY. NEXT SATURDAY IS A GOOD CANIDATE FOR THAT
WARM DAY AS IT APPEARS STRONGER SFC LOW TRACKS NORTH OF UPR
MICHIGAN...PLACING THE AREA IN A MORE DEVELOPED WARM SECTOR. WARM IS
RELATIVE AT THIS POINT. MIXING TO 925-900MB SUPPORTS HIGHS WELL INTO
THE 30S. THAT WOULD BE A PROVERBIAL HEAT WAVE COMPARED TO THE CHILL
THAT HAS BEEN OVER THE UPPER GREAT LAKES SINCE JUST BEFORE THE NEW
YEAR BEGAN.
FORECASTED PATTERN HOLDS MINIMAL CHANCE FOR MUCH IN WAY OF HIGH
IMPACT WEATHER. AFTER A DAY WITH A COLD START BUT PLENTY OF SUNSHINE
ON TUESDAY...COULD BE SOME WIDESPREAD LGT SNOW OVER THE AREA TUESDAY
NIGHT WEST/CENTRAL INTO WEDNESDAY MORNING EAST DUE TO SHORTWAVE
TROUGH AND ASSOCIATED MID- LEVEL WARM AIR ADVECTION. NAM AND GFS SHOW
MOST QPF AS THEY ARE MOST SATURATED BLO H85...BUT STILL ONLY LOOKING
AT LESS THAN 2 INCHES OF SNOW DUE TO LIMITED MOISTURE AND NOT EVEN 6
HOURS OF STEADY SNOW. EXCEPTION MAY BE OVER THE NORTHERN KEWEENAW AS
H9 TEMPS ARE ALREADY -14C WITH AN ONSHORE WSW FLOW AS BETTER FORCING
CROSSES THE AREA. MIGHT SEE LAKE ENHANCEMENT AT LEAST BRIEFLY BEFORE
WINDS VEER NORTHWEST ON WEDNESDAY MORNING. STEADILY VEERING WINDS
SHOULD KEEP CAP ON AMOUNTS VIA LAKE ENHANCEMENT. TEMPS TUESDAY NIGHT
INTO WEDNESDAY MORNING TRICKY WITH NON-DIURNAL CURVE EXPECTED DUE TO
INCREASING CLOUDS LATER AT NIGHT AS THE SYSTEM MOVES THROUGH. ONLY A
WEAK COLD FRONT PASSAGE ON WEDNESDAY...MAINLY AFFECTING THE KEWEENAW.
SOUNDINGS EVEN THERE THOUGH LOOK LESS FAVORABLE AS DAY WEARS ON WITH
DRYING ABOVE H875 AND INVERSIONS LESS THAN 5KFT. KEPT CHANCES GOING
SINCE DELTA T/S WILL BE ABOVE 15C...BUT NEGATIVE FACTORS SHOULD
HAMPER ADDITIONAL LAKE EFFECT SNOW SHOWERS. TEENS TO LOW 20S FOR
HIGHS ON WEDNESDAY.
NW FLOW ALOFT RESULTS IN ANOTHER SHORTWAVE AND SFC TROUGH CROSSING
LK SUPERIOR AND MAINLY NORTHERN UPR MICHIGAN ON WEDNESDAY NIGHT.
STRONGER FORCING AND GREATEST CHANCES FOR SNOW WILL BE OVER NORTHERN
ONTARIO CLOSER TO DEEPENING SFC LOW TRACKING TOWARD JAMES BAY. SETUP
OVER CWA SIMILAR TO TUE NIGHT WITH BEST MOISTENING/LIFT OCCURRING
ALOFT ROUGHLY H85-H6. SLIGHT CHANCES ALL AREAS...BUT ONLY CARRIED
CHANCE POPS ON KEWEENAW DUE TO HIGHER 1000-850MB RH WITH ONSHORE
WSW-W WINDS PROVIDING POSSIBLE ADDITIONAL MOISTURE. WARMING TREND
BEGINS TO BE NOTED WITH MINS WED NIGHT MOSTLY 10 ABOVE OR HIGHER
OVER ALL CWA. LAST WEEK IT WAS A STRUGGLE TO REACH 10 ABOVE FOR A
HIGH TEMPERATURE. SFC LOW CONTINUES EASTWARD AND A SW-W WIND SHOULD
STAY IN PLACE OVER UPR MICHIGAN. SMALL CHANCES ESPECIALLY NORTH AND
EAST BUT DRYING TREND SHOULD WIN OUT BY AFTN. SOUNDINGS SHOW MIXING
TO H925...WHICH ALLOWS MOST AREAS TO REACH WELL INTO THE 20S AND
SOME SPOTS TO POSSIBLY CRACK 30 DEGREES.
MODELS HAVE STEADILY TRENDED TO LESS AND LESS COLD AIR INTRUSION FOR
COLD FRONT PASSAGE ON THU NIGHT INTO FRIDAY. H925/H85 TEMPS AT 12Z
FRIDAY STILL COOLER OFF GFS AT -10C/-8C BUT ECMWF IS REALLY TRENDING
WARMER WITH VALUES ONLY -4C/-6C. GEM-NH LOOKS LIKE THE WARMER ECMWF.
ALTHOUGH LES LOOKS UNLIKELY...GFS/ECMWF/GEM-NH INDICATE SHORTWAVE
DROPPING THROUGH IN WNW FLOW ALOFT ALONG WITH SOME FORCING AND
MOISTURE ALONG COLD FRONT THAT ATTEMPTS TO DROP SOUTHWARD TOWARD
UPR MICHIGAN. LOW CHANCE POPS...NOT SURE ON THE TIMING AS MODELS
DIFFER...SEEM REASONABLE OVER THE NORTH CWA DUE TO THESE SIGNALS.
AS ALLUDED TO BEFORE...MODEL DIFFERENCES CONTINUE INTO NEXT WEEKEND
WITH REGARD TO HOW FAR SOUTH ANOTHER LOW PRESSURE TROUGH CROSSES THE
AREA. EARLIER RUNS OF ECMWF WERE MORE AGGRESSIVE IN A FARTHER SOUTH
TRACK TO LOW BUT LATEST RUNS ARE MORE LIKE THE GFS AND GEM-NH WITH
SFC LOW AND MOST PRECIP STAYING NORTH OF UPR MICHIGAN OR AT LEAST
DELAYED INTO UPR GREAT LAKES. DID NOT STRAY TOO MUCH FM CONSENSUS
GUIDANCE FOR NEXT WEEKEND...BUT WITH THE TREND FM ECMWF...HEADED
TOWARD WARMER TEMPS INTO THE 30S MOST AREAS ON SATURDAY WITH
EXPECTATION THAT CWA WILL BE WITHIN WARM SECTOR MOST OF THE DAY.
INTERESTING THAT MEX GUIDANCE /EXTENDED GFS MOS NUMBERS/ CHECKS
IN AT 33-40F FOR NEXT SATURDAY OVER THE CWA. CLIMO IN THE LOW-MID
20S...SO THAT IS A DECENT DEPARTURE FM AVERAGE AT A POINT IN MOS
WHERE THERE IS USUALLY A BIAS BACK TOWARD CLIMO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 636 AM EST MON JAN 12 2015
IN THE WAKE OF A COLD FRONT THAT HAS PASSED...LAKE EFFECT SNOW WILL
CONTINUE OFF LAKE SUPERIOR TODAY. THIS MORNING....EXPECT IFR
CONDITIONS ALONG WITH PERIODS OF MVFR AT KIWD/KCMX/KSAW. IFR SHOULD
BE MORE FREQUENT AT KIWD/KSAW WHERE A MORE DIRECT UPSLOPE FLOW WILL
SUPPORT HEAVIER/MORE PERSISTENT SNOW SHOWERS THAN AT KCMX.
CONDITIONS WILL IMPROVE TO MVFR DURING THE AFTN AS SUBSIDENCE
INCREASES AND LOW-LEVEL FLOW BECOMES MORE ANTICYCLONIC WITH APPROACH
OF STRONG HIGH PRES. AS THE HIGH MOVES INTO THE WRN GREAT LAKES
REGION TONIGHT...WINDS WILL BACK AND DIMINISHING LAKE EFFECT WILL
SHIFT OFFSHORE...RESULTING IN IMPROVEMENT TO VFR AT ALL TERMINALS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 456 AM EST MON JAN 12 2015
TYPICALLY STRONG WINDS FOR WINTER EXPECTED MUCH OF THIS LAST WEEK OF
THE SHIPPING SEASON. NORTH WINDS TO 30 KTS THIS MORNING DIMINISH TO
LESS THAN 20 KTS BRIEFLY TONIGHT. WITH A SURGE OF ARCTIC AIR AND
BUILDING WAVES...EXPECT A PERIOD OF HEAVY FREEZING SPRAY OVER MUCH
OF THE LAKE IN LINE WITH GOING WARNINGS. WINDS RAMP UP TO 30 KTS FM
THE WEST OR SOUTHWEST TUESDAY AND TUESDAY NIGHT AHEAD OF AN COLD
FRONT. STRONGEST WINDS OVER WESTERN LK SUPERIOR...AND CANNOT COUNT
OUT A PERIOD OF GALES BTWN ISLE ROYALE AND THE KEWEENAW LATE
TUESDAY. ADDITIONAL HEAVY FREEZING SPRAY IS POSSIBLE OVER WESTERN LK
SUPERIOR DURING THIS TIME. COLD FRONT SLIDES OVER THE LAKE ON
WEDNESDAY AND WINDS SETTLE DOWN TO LESS THAN 25 KTS BY WEDNESDAY
AFTN. LULL IS BRIEF AS WEST WINDS INCREASE TO 25-30 KTS BY THURSDAY
MORNING OUT AHEAD OF ANOTHER COLD FRONT THAT DROPS OVER LK SUPERIOR
ON FRIDAY. THOUGH WINDS DIMINISH TO LESS THAN 25 KTS LATER ON
FRIDAY...WINDS INCREASE AGAIN BY NEXT SATURDAY FM THE SOUTH OUT OF
AN APPROACHING LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ248>251-265>267.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR LSZ162.
HEAVY FREEZING SPRAY WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
LSZ243-244-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR LSZ241-242-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
600 AM EST MON JAN 12 2015
.AVIATION...
BY 12Z...SNOW WILL DIMINISH TO FLURRIES AT PTK WHILE FNT AND MBS
REMAIN FREE OF SNOW. THE PASSAGE OF A SECONDARY COLD FRONT LATE THIS
MORNING INTO EARLY AFTERNOON WILL BACK THE WINDS TOWARD THE NNW.
GUSTS WILL INCREASE TO 20 KNOTS THIS AFTERNOON AS ARCTIC AIR FILTERS
IN FROM THE NORTH. UPSTREAM OBS AND MODEL SOUNDINGS SUGGEST THERE
WILL BE A GOOD DEGREE OF VARIABILITY IN CEILING HEIGHTS LATER THIS
MORNING AND AFTERNOON. THE ARCTIC AIR FUNNELING INTO THE AREA WILL
BE SHALLOW WHICH WILL FOSTER THE DEVELOPMENT OF A LOW LEVEL
INVERSION. THIS SUPPORTS HOLDING ONTO HIGH MVFR AND/OR LOW VFR
CEILINGS UNTIL THIS WHEN WHEN DRY AIR ADVECTION PROVIDES A CLEARING
TREND.
FOR DTW...THE SNOW WILL DIMINISH BETWEEN 12Z AND 15Z BEFORE ENDING
BY 16Z. ADDITIONAL ACCUMULATIONS AFTER 12Z SHOULD BE LESS THAN A
HALF INCH.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING BELOW 5000 FEET THIS MORNING AND AFTERNOON. LOW
TONIGHT.
&&
.PREV DISCUSSION...ISSUED 346 AM EST MON JAN 12 2015
SHORT TERM...TODAY AND TONIGHT
AFTER A LULL IN THE SNOW SHORTLY AFTER MIDNIGHT...TRENDS IN THE
RADAR AND SFC OBS ARE SHOWING A REINTENSIFICATION OF SNOWFALL ACROSS
NRN INDIANA INTO SE MI. THIS IS THE RESULT OF A RENEWED
STRENGTHENING OF SOME MID TROPOSPHERIC FRONTAL FORCING /IN THE 800-
700MB LAYER/ AND WILL TARGET LOCALS SOUTH OF A SANDUSKY TO OWOSSO
LINE EARLY THIS MORNING. THE FRONTAL CIRCULATION WILL ADVANCE TO THE
EAST DURING THE COURSE OF THE MORNING AS THE UPPER JET SUPPORT
SLIDES EAST OF THE STATE. THE CURRENT NAM AND SEVERAL HI RES
SOLUTIONS SUGGEST THE FORCING WILL WEAKEN AS IT HEADS EAST OF METRO
DETROIT BETWEEN 12Z AND 15Z THIS MORNING. SNOWFALL INTENSITY WILL
FLUCTUATE DURING THE MORNING AS THE STRENGTH OF THE MID LEVEL LIFT
VARIES. IN LIGHT OF THE FORCING AND PROJECTED NEAR TERM QPF
AMOUNTS...ADDITIONAL SNOWFALL ACCUMS BETWEEN A HALF INCH AND INCH
THROUGH DAYBREAK STILL SEEM REASONABLE. BASED ON REPORTS PRIOR TO
MIDNIGHT...THIS SHOULD LEAD TO TOTAL SNOWFALL SOUTH OF A BAD AXE TO
SAGINAW LINE OF 1 TO 3 INCHES. THE HIGHER TOTALS WILL OCCUR ACROSS
THE NRN DETROIT SUBURBS WHERE FORCING WAS A LITTLE MORE PERSISTENT
OVERNIGHT. THERE IS A SECONDARY REGION OF RADAR RETURNS PUSHING
SOUTH ACROSS NRN LOWER MI...OCCURRING ALONG THE 600-500MB PORTION OF
THE FRONT. THE FORCING IS EXPECTED TO WEAKEN AS IT ENTERS THE
SAGINAW VALLEY AND THUMB EARLY THIS MORNING. UPSTREAM RETURNS
HOWEVER SUPPORT AT LEAST CHANCE POPS ACROSS THE NRN THIRD OF THE
FORECAST AREA THIS MORNING. UNTREATED ROADS WILL BE VERY SLICK THIS
MORNING AS THIS SNOW HAS A HIGH WATER CONTENT. WITH TEMPS IN THE
UPPER 20S...ROAD TREATMENTS SHOULD PROVE HIGHLY EFFECTIVE.
WHILE THE COLD FRONT WILL MOVE EAST OF THE AREA EARLY THIS
MORNING...THE PUSH OF ARCTIC AIR WILL NOT ARRIVE INTO SE MI UNTIL
THIS AFTERNOON UNDER STRENGTHENING NORTHERLY WINDS. THIS WILL
SUPPORT MORNING HIGHS /MID 20S TO LOW 30S/...WITH FALLING TEMPS
DURING THE AFTERNOON. WHILE THE MID LEVEL TROUGH AXIS NOW
APPROACHING LAKE SUPERIOR WILL NOT TRAVERSE SE MI UNTIL THIS
EVENING...LARGE SCALE SUBSIDENCE WITHIN THE DESCENDING BRANCH OF THE
MID TROP FRONT WILL LEAD TO SUBSTANTIAL MID LEVEL DRYING THIS
AFTERNOON. THIS WILL KEEP CONDITIONS PRECIP FREE OUTSIDE OF SOME
LAKE EFFECT SNOW SHOWERS OVER THE THUMB REGION UNDER NORTHERLY FLOW.
THE NAM AND 4KM WRF NMM SHOW A DOMINATE LAKE BAND DEVELOPING OVER
THE SRN LAKE HURON BASIN THIS EVENING. THE COLD AIR ADVECTION WILL
BE SHALLOW...SUPPORTING EQUILIBRIUM LEVELS ONLY TO 5K FT.
HOWEVER...STEEP LOW LEVEL LAPSE RATES WITH TEMPS OF -16 TO -18C NEAR
THE NEAR THE TOP OF THE MIXED LAYER COULD LEAD TO SOME GOOD SNOWFALL
RATES. A GRADUAL BACKING OF THE FLOW TO THE NNE AIDED BY A LAND
BREEZE PUSH OFF ONTARIO MAY BRING THIS BAND INTO THE ERN THUMB AND
PORT HURON. WILL KEEP ANY ACCUMS MINOR ATTM /AN INCH OR TWO IN PORT
HURON/. LAKE STRATO CU SHOULD PUSH INTO PORTIONS OF FLINT AND METRO
DETROIT TONIGHT. NAM AND RUC SOUNDINGS SHOW GOOD SUPERSATURATION
WITH RESPECT TO ICE AROUND -16C. THIS MAY BE SUPPORTIVE OF SOME
FLURRIES/LIGHT SNOW SHOWERS OUT OF THE STRATO CU. REGIONS THAT SEE
THE CLOUDS TONIGHT WILL HAVE MIN TEMPS HOLD IN THE SINGLE
DIGITS...WHILE LOCALS ACROSS THE WRN HALF OF THE FORECAST AREA
SHOULD DECOUPLE ENOUGH TO SUPPORT SUB ZERO MINS.
LONG TERM...TUESDAY THROUGH SUNDAY
STRONG SURFACE HIGH PRESSURE WILL REMAIN SPRAWLED OVER THE GREAT
LAKES TUESDAY AND TUESDAY NIGHT. THIS WILL BRING QUIET WEATHER TO
THE AREA AS LAKE EFFECT POTENTIAL OFF LAKE HURON LOOKS TO DECREASE
BY SUNRISE. THIS WILL OCCUR AS INVERSION HEIGHTS/CONVECTIVE DEPTHS
DECREASE AS THE HIGH SETTLES IN...AND AS WINDS TURN MORE EASTERLY
DECREASING THE FETCH. THE DAY SHOULD START OUT WITH PLENTY OF
STRATUS LOCKED UNDER THE INVERSION STRETCHING FROM THE THUMB DOWN TO
THE DETROIT AREA. THIS LAYER SHOULD MIX OUT LATER IN THE AFTERNOON
HOWEVER PER LATEST FORECAST SOUNDINGS FROM NAM/GFS. UPSTREAM
OBSERVATIONS DEPICT A VERY DRY AND COLD AIRMASS UNDER THE RIDGE OVER
CANADA AND THE NORTHERN PLAINS (CURRENT DEWPOINTS -20 TO -30
F...WITH MAX TEMPS YESTERDAY BETWEEN -5 AND 15 F). THE AIRMASS
SHOULD MODIFY SOME AS IT CROSSES THE STILL UNFROZEN GREAT
LAKES...AND EXPECTING MAX TEMPS TUESDAY TO REACH THE MID TEENS. IT
IS POSSIBLE IF WE GET ENOUGH SUNSHINE WE COULD OVERACHIEVE...BUT
WILL LEAN THE FORECAST ON THE PESSIMISTIC SIDE GIVEN HIGH POTENTIAL
FOR LAKE STRATUS DURING THE EARLY PART OF THE DAY. MINS OVERNIGHT
WILL BECOME VERY COLD AS EXCELLENT RADIATIONAL COOLING CONDITIONS SET
UP UNDER THE RIDGE CENTER...WITH CLEAR SKIES...LIGHT/CALM
WINDS...FRESH SNOW...AND A VERY DRY AIRMASS. CONTINUED TREND FROM
INHERITED FORECAST WITH MIN TEMPS BELOW MOS GUIDANCE...FROM NEAR
ZERO TO ABOUT 7 BELOW.
WEAK UPPER SHORTWAVE WILL CLIP ACROSS MICHIGAN WEDNESDAY AS IT
PIVOTS AROUND THE UPPER VORTEX CENTERED NORTH OF HUDSON BAY. SURFACE
REFLECTION LOOKS VERY WEAK...AND WILL ONLY MAKE A SMALL RIPPLE IN
THE SURFACE HIGH STILL EXTENDING FROM THE CENTRAL PLAINS UP THROUGH
THE OHIO VALLEY. FRONTAL BOUNDARY WILL WASH OUT AS IT CROSSES
MICHIGAN WITH THIS SYSTEM...BUT FORCING LOOKS TOO WEAK TO OVERCOME
VERY DRY AIRMASS THAT WILL PRECEDE IT. THE RIDGE AXIS WILL GET
PUSHED TO OUR SOUTH AND EAST WEDNESDAY NIGHT AND THURSDAY AS ANOTHER
CLIPPER SYSTEM IS GUIDED ACROSS ONTARIO AROUND THE VORTEX NORTH OF
HUDSON BAY. PRECIPITATION ASSOCIATED WITH THIS SYSTEM LOOKS TO
REMAIN WELL TO OUR NORTH.
BY FRIDAY MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH ANOTHER
RIDGE OF SURFACE HIGH PRESSURE ENCOMPASSING THE GREAT LAKES...BUT
DIFFER WITH THE AMPLIFICATION OF THE UPSTREAM PATTERN OVER THE
WESTERN U.S. AND CANADA. THIS RESULTS IN SOME UNCERTAINTY WITH THE
FORECAST AS WE HEAD INTO THE WEEKEND AND EARLY NEXT WEEK AS MODEL
SOLUTIONS DIFFER GREATLY IN TIMING THE ARRIVAL OF GULF OF ALASKA
ENERGY INTO THE GREAT LAKES. 00Z EURO/GEM CURRENTLY HAVE THE
STRONGEST CONSENSUS AT 144 HOURS...BUT RUN TO RUN CONSISTENCY IN THE
EURO HAS NOT BEEN STRONG. BOTH THESE SOLUTIONS TRACK SURFACE LOW
PRESSURE INTO THE GREAT LAKES ON SATURDAY...BUT WITH ENOUGH OF A
NORTHERLY TRACK TO KEEP MOST PRECIPITATION OUT OF SOUTHEAST MICHIGAN
SO THE FORECAST REMAINS DRY. ADDITIONAL ENERGY LOOKS TO
FOLLOW...POSSIBLY SETTING US UP IN A MORE ACTIVE PATTERN FOR EARLY
NEXT WEEK. TEMPERATURES DO LOOK TO MODERATE FRIDAY AND THROUGH THE
WEEKEND AS ARCTIC CLIPPERS STOP DIVING THROUGH THE AREA. EXPECTING
MAX TEMPS TO WARM BACK CLOSER TO FREEZING.
MARINE...
GUSTY WINDS WILL DEVELOP OVER LAKE HURON TODAY IN THE WAKE OF AN
EARLY MORNING COLD FRONT. NORTHWESTERLY WIND GUSTS TO 30 KNOTS WILL
BE POSSIBLE OVER ALL BUT INNER SAGINAW BAY. WAVE HEIGHTS WILL ALSO
INCREASE TO AS HIGH AS 7 FEET OVER ICE FREE AREAS THIS AFTERNOON AND
EARLY TONIGHT AS THE FETCH INCREASES. THE COMBINATION OF GUSTY
WINDS...LARGE WAVES...AND COLD TEMPERATURES WILL ALSO CREATE AREAS
OF HEAVY FREEZING SPRAY OVER CENTRAL AND SOUTHERN LAKE
HURON...ESPECIALLY OVER THE OPEN WATERS AND OFF THE TIP OF THE
THUMB. STRONG HIGH PRESSURE BUILDING INTO THE GREAT LAKES TONIGHT
WILL ALLOW FOR A GRADUAL DECREASE IN WINDS AND WAVES TONIGHT. THE
HIGH WILL THEN BRING VERY LIGHT WINDS AS IT SETTLES OVERHEAD ON
TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST
TUESDAY FOR LHZ363-421-441-462>464.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR LHZ421-441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
SHORT TERM...SC
LONG TERM....HLO
MARINE.......HLO
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BUFFALO NY
648 AM EST MON JAN 12 2015
.SYNOPSIS...
A WAVE OF LOW PRESSURE EXTENDING FROM THE GREAT LAKES TO THE OHIO
VALLEY WILL SLIDE TO THE ATLANTIC COASTLINE TODAY WHICH WILL BRING A
WIDESPREAD SNOWFALL TO THE REGION. SNOW WILL TAPER OFF LATE TODAY
WITH A BRIEF PERIOD OF LIGHT LAKE EFFECT SNOW SOUTH OF LAKE ONTARIO
TONIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION TUESDAY WITH FAIR
WEATHER AND MODERATING TEMPERATURES THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A COMPLEX SYSTEM WILL BRING LIGHT SNOW TO THE REGION TODAY. THERE
WILL BE SEVERAL RATHER SUBTLE FEATURES WHICH CONTRIBUTE TO LIFT
WITH THIS SYSTEM...WHICH WILL RESULT IN VARIABLE SNOWFALL RATES.
WILL TRY TO BREAK THESE DOWN...BUT IN A GENERAL SENSE EXPECT A
TOTAL OF 2 TO 4 INCHES THROUGH TODAY IN MOST AREAS...EXCEPT LESSER
AMOUNTS OF 1 TO 3 INCHES IN THE GENESEE VALLEY.
AN INITIAL BAND OF SNOW LIFTED ACROSS THE REGION DURING THE EARLY
MORNING HOURS...WITH THIS NOW EXITING INTO NEW ENGLAND. SNOW HAS
TEMPORARILY TAPERED OFF BEHIND THIS. THE NEXT ROUND WILL COME
WITH THE SURFACE TROUGH AND ASSOCIATED WIND SHIFT. THE SHIFT TO
NORTHWEST WINDS WILL ENHANCE SURFACE CONVERGENCE AND BRING
ANOTHER ROUND OF STEADIER SNOWS TO THE REGION. AT 630 AM...THIS
AREA CAN BE SEEN ON RADAR ENTERING WESTERN NEW YORK. THE STEADIEST
SNOWS WITH THIS WILL BE ACROSS HIGHER TERRAN EAST OF THE LAKES
(CHAUTAUQUA RIDGE/BOSTON HILLS/TUG HILL) DUE TO OROGRAPHIC LIFT.
THIS SAID...WE ARE STILL LOOKING AT A COUPLE INCHES IN A FOUR HOUR
PERIOD. SNOW WILL TAPER OFF FROM NW-SE THIS AFTERNOON WITH THE
EXIT OF THE WEAK TROUGH OF LOW PRESSURE.
MODEL GUIDANCE APPEARS TO HAVE A GOOD HANDLE ON THIS SYNOPTIC
SYSTEM...WITH THE HRRR PROBABLY DOING THE BEST JOB OF CAPTURING
THESE COMPLEX FEATURES AND VARIABLE SNOW INTENSITY. NEAR FREEZING
SURFACE TEMPERATURES HAS LEAD TO SNOW RATIOS AROUND 10:1 AND GIVEN
QPF THIS SHOULD KEEP MOST AREAS BELOW ADVISORY CRITERIA...ESPECIALLY
CONSIDERING THE LENGTH OF THE EVENT AND MODEST SNOWFALL RATES.
A COLD FRONT WILL DROP ACROSS THE REGION LATE THIS AFTERNOON AND
EARLY EVENING. THIS IS LIKELY TO BRING SNOW SHOWERS TO THE EASTERN
LAKE ONTARIO REGION...AND EVENTUALLY SOME LIGHT LAKE EFFECT SNOW
SOUTH OF LAKE ONTARIO TONIGHT. THE COLD AIR WILL BE SHALLOW WITH
THE COLDEST AIR OF AROUND -20C BENEATH 850MB. LOW EQUILIBRIUM
LEVELS BUT AMPLE DENDRITIC SNOW GROWTH SHOULD LEAD TO LIGHT LAKE
EFFECT SNOWS SOUTH OF LAKE ONTARIO WHICH WILL BE AIDED BY
UPSLOPING. ACCUMULATIONS SHOULD BE LIGHT...ONLY AN INCH OR TWO IN
MOST AREAS...BUT SNOW MAY BE PERSISTENT FOR MUCH OF THE NIGHT WITH
DISORGANIZED MULTIPLE BANDS.
THE FRONT WILL USHER IN MUCH COLDER AIR...BUT PERSISTENT CLOUD
COVER SHOULD HAVE AREAS SOUTH OF LAKE ONTARIO WARMER THAN MOST
GUIDANCE. THE COLDEST TEMPERATURES WILL BE EAST OF LAKE ONTARIO
WHERE SKIES SHOULD CLEAR WITHOUT LAKE MOISTURE. THIS WILL ALLOW
FOR BETTER RADIATIONAL COOLING WITH LOWS WELL BELOW ZERO AND WIND
CHILLS APPROACHING 20 BELOW.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
TUESDAY A BROAD AREA OF SURFACE HIGH PRESSURE WILL BE ADVANCING
EASTWARD ACROSS THE GREAT LAKES REGION. AHEAD OF THIS FEATURE...ON A
NORTHERLY FLOW...THERE LIKELY WILL BE ENOUGH LOW LEVEL MOISTURE
WITHIN AN ARCTIC AIRMASS TO GENERATE LAKE EFFECT SNOW SHOWERS OFF
LAKE ONTARIO...WITH ACTIVITY ALSO POSSIBLY BRUSHING THE EASTERN LAKE
ERIE SHORELINE OF THE SOUTHERN TIER ON A NORTH-NORTHEASTERLY WIND.
DUE TO THE SHALLOWNESS OF THE MOISTURE...AND ONLY FAIR LAKE
INSTABILITY PARAMETERS...SNOWFALL TUESDAY MORNING WILL ONLY BE AN
ADDITIONAL HALF INCH NEAR THE SOUTHERN LAKE ONTARIO SHORELINE.
OTHERWISE A COLD START TO THE DAY AS -14C 850 HPA AIR FLOWS OVER THE
REGION. WITHIN THE DRY...ARCTIC AIRMASS SKIES WILL BECOME MOSTLY
SUNNY BY AFTERNOON...AFTER WANING LAKE EFFECT ACTIVITY DIMINISHING.
HIGHS WILL STRUGGLE TO REACH DOUBLE DIGITS AS THE LIGHT NORTHERLY
FLOW REPLENISHES THE COLD SURFACE AIR.
CLEAR AND COLD TUESDAY NIGHT AS SURFACE HIGH PRESSURE DRAWS CLOSER.
LIGHT WINDS AND GOOD RADIATIONAL COOLING WILL ALLOW MOST AREAS TO
DROP TO ZERO...AND INTO THE NEGATIVE TEENS/-20F ACROSS THE NORTH
COUNTRY WHERE A DEEP AND YET FRESH SNOWPACK ENHANCES THE RADIATIONAL
COOLING. BECAUSE OF THE LIGHT WINDS...WIND CHILL HEADLINES ARE NOT
LIKELY.
SUNNY AND DRY WEDNESDAY WITH THE SURFACE HIGH PRESSURE OVERHEAD.
LIGHT SOUTHERLY WINDS AGAIN WILL ALLOW FOR OVERNIGHT LOWS TO QUICKLY
DROP...INTO THE SINGLE DIGITS SOUTH OF LAKE ONTARIO...AND NEAR ZERO
EAST OF LAKE ONTARIO.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A QUIET WEATHER PATTERN IS EXPECTED TO CLOSE OUT THE WORK WEEK.
TEMPERATURES WILL MODERATE TO NEAR NORMAL VALUES BY THURSDAY AS
SURFACE HIGH PRESSURE SLIDES EASTWARD AND BRINGS LIGHT SOUTHERLY
WINDS BACK ACROSS THE AREA. A COLD FRONT LOOKS TO PASS THE AREA ON
FRIDAY...HOWEVER THE BULK OF THE MOISTURE WILL REMAIN WELL TO OUR
NORTH...BOTH LIMITING THE SYNOPTIC SNOW POSSIBILITY FRIDAY...AND
LAKE EFFECT ACTIVITY INTO THE START OF THE WEEKEND. LOOKING TOWARD
NEXT WEEK...GLOBAL MODELS ARE IN FAIR AGREEMENT THAT THERE WONT BE
MUCH COLD AIR AROUND. OVERALL TEMPERATURES LOOKS AVERAGE TO SLIGHTLY
ABOVE AVERAGE...WITH A FEW CHANCES FOR SOME SOUTHERN STREAM WAVES TO
BRING SOME LIGHT PRECIPITATION AT TIMES.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
IT IS A VERY DIFFICULT FORECAST THIS MORNING...WITH SEVERAL
FEATURES TO CONTEND WITH. EXPECT CONDITIONS TO VARY BETWEEN
IFR/MVFR IN BETWEEN ROUNDS OF STEADIER SNOWS. IN GENERAL...A WEAK
SURFACE TROUGH WILL CROSS THE REGION THIS MORNING AND BRING
STEADIER SNOWS AND A SHIFT TO NORTHWESTERLY WINDS. VSBY SHOULD
AVERAGE 1 TO 3 SM IN SNOW...WITH MOSTLY IFR CIGS.
EXPECT IMPROVING CONDITIONS THIS AFTERNOON AS THIS WAVE EXITS
EAST...BUT THIS WILL PROBABLY BE SHORT LIVED. A COLD FRONT WILL DROP
SOUTHWARD ACROSS THE REGION LATE THIS AFTERNOON AND EARLY EVENING.
THIS WILL BRING A LOW INVERSION WITH COLDER TEMPERATURES LIKELY TO
TRAP LAKE MOISTURE BENEATH IT. THERE ALSO WILL BE AMPLE NORTHERLY FLOW
TO GENERATE SOME LIGHT SNOW SHOWERS SOUTH OF LAKE ONTARIO. WHILE
MIXING MAY INITIALLY PREVENT LOW CLOUDS FROM FORMING THIS
EVENING...EXPECT AN IFR CLOUD DECK TO DEVELOP LATE EVENING AND
LAST THROUGH AT LEAST 12Z TUESDAY.
OUTLOOK...
TUESDAY...IFR CIGS EARLY SOUTH OF LAKE ONTARIO...IMPROVING IN THE AFTERNOON.
TUESDAY NIGHT THROUGH FRIDAY...MAINLY VFR.
&&
.MARINE...
A COLD FRONT WILL DROP SOUTH ACROSS THE LOWER LAKES LATE THIS
AFTERNOON...FOLLOWED BY A BRIEF SURGE OF MODERATE NORTHWESTERLY TO
NORTHERLY WINDS WHICH WILL PRODUCE SMALL CRAFT ADVISORY LEVEL
CONDITIONS ON BOTH LAKES MONDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
INTO THE GREAT LAKES BY TUESDAY MORNING ALONG WITH DIMINISHING WINDS
AND WAVES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 4 AM EST
TUESDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 4 AM
EST TUESDAY FOR LOZ030.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 7 AM EST
TUESDAY FOR LOZ042>045.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...CHURCH/THOMAS
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1040 AM EST MON JAN 12 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL TRACK NORTHEAST OVER THE
EASTERN CAROLINAS AND MID ATLANTIC COAST THROUGH TONIGHT. A SERIES
OF UPPER LEVEL DISTURBANCES WILL MAINTAIN AN UNSETTLED WEATHER
PATTERN OVER THE CAROLINAS THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1040 AM MONDAY...
THE SHIELD OF RAIN THAT MOVED ACROSS CENTRAL NC DURING THIS
MORNING`S COMMUTE HAS MOVED EAST OF I-95...AS THE ASSOC LOW-MID
LEVEL MESO-VORT IS NOW LIFTING UP ACROSS NE NC ATTM (PER 88D). FOR
THE REST OF THIS MORNING...THE RAIN WILL BE MORE PATCHY IN NATURE
ACROSS THE TRIANGLE AND TRIAD REGIONS...WITH SYNOPTIC SCALE LIFT
WEAKENING IN THE WAKE OF THE AFOREMENTIONED DEPARTING VORT FEATURE.
MEANWHILE... WE`RE KEEPING OUR EYES ON THE ANOTHER LOW-LEVEL WAVE
AND AREA OF RAIN LIFTING NE ACROSS ERN GA AND SRN SC...BASICALLY
LIFTING NE UP ALONG THE STATIONARY SFC BOUNDARY THAT`S PRESENTLY
STRETCHING FROM COASTAL SC NWD ALONG THE NC HWY 17 CORRIDOR. CURRENT
HIRES NEAR-TERM GUIDANCE SUGGESTS THIS RAIN WILL MOVE UP INTO E-
CNTRAL AND ERN NC BY MID-DAY OR EARLY AFTERNOON...BASICALLY CATCHING
UP TO AND FILLING IN BEHIND THE RAIN THAT`S PRESENTLY FALLING EAST
OF I-95. AS SUCH...LOOK FOR A WET AFTERNOON ACROSS THE ERN HALF OF
OUR CWA...MAINLY EAST OF THE US-1 CORRIDOR...BUT ESP ALONG THE I-95
CORRIDOR AND EWD. WHILE SOME THUNDER CAN`T BE RULED OUT EARLY THIS
AFTERNOON ALONG THE SRN I-95 CORRIDOR WHEN THE RAIN SHIELD FIRST
MOVES UP IN THE SE NC...THE LATEST MESO-ANALYSIS AND HRRR SUGGEST
THE BEST LAPSE RATES AND INSTABILITY SHOULD REMAIN ALONG OR JUST OFF
THE COAST...WILL MONITOR. WHILE THE BULK OF THE RAIN...AND HEAVIEST
RAIN SHOULD REMAIN EAST OF US-1...LIGHT RAIN OR PATCHY DRIZZLE WILL
STILL BE POSSIBLE WEST OF US-1 THROUGH THE DAY. TEMPS WILL VARY
QUITE A BIT FROM NW TO SE: COOLEST NW (HIGHS ONLY REACHING THE LOW
40S)...AND WARMEST SE NEAR THE SFC WAVE AND BOUNDARY (MID-50S).
TONIGHT...A NEARLY SATURATED AIR MASS WILL REMAIN IN PLACE THOUGH
PRECIP WILL BE CONFINED TO MAINLY DRIZZLE AND SPOTS OF LIGHT RAIN AS
LIFT THROUGH THE COLUMN RATHER WEAK. A COLD FRONT ASSOCIATED WITH A
S/W CROSSING THE GREAT LAKES INTO SOUTHERN NEW ENGLAND WILL DRAG A
COLD FRONT TOWARD CENTRAL NC THIS EVENING AND INTO OUR NORTHERN
COUNTIES AFTER MIDNIGHT. CONVERGENCE ALONG THIS BOUNDARY MAY ENHANCE
THE SPOTTY LIGHT RAIN OR DRIZZLE COVERAGE OVERNIGHT. TEMPS THIS
EVENING WILL BE JUST A FEW DEGREES COOLER THAN AFTERNOON TEMPS. THE
PASSAGE OF THE COLD FRONT ACROSS THE NORTH SHOULD CAUSE TEMPS TO
COOL DURING THE PRE-DAWN HOURS. MIN TEMPS MID 30S ACROSS THE FAR
NORTH TO THE LOWER 40S FAR SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 320 AM MONDAY...
TUESDAY THROUGH WEDNESDAY: A REINFORCING SHOT OF COLD DRY AIR IN THE
LOW LEVELS WILL ARRIVE ON TUESDAY AS A STRONG ~1040 MB SURFACE
BUILDS SOUTHWARD FROM THE EASTERN GREAT LAKES AND NORTHEASTERN U.S.
OUR DAYTIME HIGH TEMPS WILL LIKELY OCCUR AROUND DAYBREAK FOR MOST IF
NOT ALL OF CENTRAL NC... WITH TEMPS FALLING THROUGHOUT THE DAY.
MEANWHILE A WEAK SOUTHERN STREAM S/W DISTURBANCE ALOFT WILL APPROACH
THE AREA FROM THE WEST-SOUTHWEST ON TUESDAY AND MOVE ACROSS THE
REGION ON TUESDAY NIGHT/WEDNESDAY MORNING. SOME LIGHT RAIN AND/OR
DRIZZLE MAY DEVELOP ACROSS THE AREA ON TUESDAY AFTERNOON IN RESPONSE
TO THE APPROACHING DISTURBANCE. THE BEST CHANCE OF PRECIP THOUGH
APPEARS TO BE LATE TUESDAY EVENING INTO EARLY WEDNESDAY MORNING...
WITH THE HIGHEST CHANCES ACROSS THE COASTAL PLAIN AND SOUTHERN
SANDHILLS.
GIVEN THE STRONG HIGH TO THE NORTH OF THE AREA AND LIGHT PRECIP...
WE MAY HAVE SOME PROBLEMS WITH LIGHT FREEZING RAIN AND/OR FREEZING
DRIZZLE ACROSS PORTIONS OF THE AREA FROM LATE TUESDAY THROUGH
WEDNESDAY MORNING (AS WE DO NOT HAVE SATURATION ALOFT ABOVE
-10C)... MAYBE EVEN INTO EARLY WEDNESDAY AFTERNOON. IN ADDITION...
PARTIAL THICKNESS VALUES DO INDICATE THE POSSIBILITY OF SOME SLEET
MIXING IN ACROSS THE FAR NORTHERN PIEDMONT EARLY WEDNESDAY MORNING.
THIS APPEARS POSSIBLE WITH THE LATEST GFS SOUNDING SHOWING THE
LOWEST 3-4 KFT OF THE ATMO BELOW FREEZING ALONG WITH A COLD NOES OF
AROUND -6 TO -7 DEGREES C EARLY WEDNESDAY MORNING ACROSS THE FAR
NORTHERN PIEDMONT. HOWEVER... WILL OMIT FROM THE FORECAST AT THIS
TIME AND FOCUS THE P-TYPE ON FREEZING RAIN/DRIZZLE ACROSS THESE
AREAS (MOST IMPACTFUL FOR THIS EVENT).
WHILE PRECIP AMOUNTS ARE EXPECTED TO BE LIGHT... GENERALLY LESS THAN
A TENTH OF AN INCH... TEMPS ARE EXPECTED TO FALL INTO THE UPPER 20S
TO AROUND 30 ACROSS THE PIEDMONT AND PORTIONS OF THE NORTHERN AND
CENTRAL COASTAL PLAIN ON WEDNESDAY MORNING. THIS WILL LIKELY SET THE
STAGE FOR SOME LIGHT ICE ACCRUAL ACROSS THE AFOREMENTIONED AREA.
DESPITE THE LOW PRECIP AMOUNTS... ONLY A FEW HUNDREDTHS OF ICE
ACCRUAL COULD CAUSE SOME SIGNIFICANT TRAVEL PROBLEMS FOR WEDNESDAY
MORNING... DESPITE THE LOW PRECIP TOTALS... ESPECIALLY ON ELEVATED
SURFACES SUCH AS BRIDGES AND OVERPASSES. HOWEVER... ALL WILL HINGE
ON THE PRECIP... AS WE MAY NOT SEE MUCH... IF ANYTHING WEST OF LINE
FROM ASHEBORO TO BURLINGTON. THUS... CONFIDENCE IS INCREASING THAT
WE MAY NEED A WINTER WX ADVISORY OVER PORTIONS OF THE PIEDMONT (IF
NOT ALL) AND NORTHERN AND CENTRAL COASTAL PLAIN FOR LATE TUESDAY
EVENING INTO WEDNESDAY MORNING... THOUGH HOW FAR WEST TO TAKE AN
ADVISORY IS STILL VERY UP IN THE AIR. STAY TUNED FOR LATER FORECASTS.
AS MENTIONED ABOVE HIGHS FOR THE DAYLIGHT HOURS ON TUESDAY WILL
OCCUR EARLY IN THE DAY... LIKELY NEAR DAYBREAK. THUS... WILL GO WITH
HIGH TEMPS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTH...
AND LIKELY FALLING THROUGH THE DAY. LOWS WEDNESDAY MORNING ARE
EXPECTED TO RANGE FROM THE UPPER 20S IN THE HEART OF THE COLD AIR
DAMMING WEDGE TO THE LOWER 30S SOUTH AND EAST. HIGHS ON WEDNESDAY
ARE EXPECTED TO BE IN THE MID TO UPPER 30S... WITH LOCATIONS ACROSS
THE NORTHEAST PIEDMONT LINGERING BELOW FREEZING THE LONGEST GIVEN
THE PRECIP SHOULD END IN AN WEST TO EAST FASHION ON WEDNESDAY.
HOWEVER... WE SHOULD REMAIN LOCKED INTO THE CAD AIRMASS.
WEDNESDAY NIGHT: BEST MOISTURE AND LIFT IS EXPECTED TO PUSH JUST TO
THE EAST OF THE AREA BY WEDNESDAY NIGHT... WITH MAYBE SOME LINGERING
LIGHT RAIN AND OR DRIZZLE ACROSS THE COASTAL PLAIN. THE MAIN SURFACE
HIGH TO THE NORTH SHOULD BEGIN TO SHIFT EASTWARD. THUS... WILL KEEP
ANY MENTION OF PRECIP ACROSS THE COASTAL PLAIN AS A COLD RAIN.
EXPECT LOWS WILL RANGE FROM 30/LOWER 30S NORTHWEST TO THE MID 30S SE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...
A POSITIVE TILT TROUGH WILL APPROACH CENTRAL NC FROM THE WEST THU
AND EXIT THE REGION BY EARLY FRIDAY. MEDIUM RANGE GUIDANCE STILL
OFFER VARYING SOLUTIONS REGARDING THE PRECIP SHIELD ASSOCIATED WITH
THIS SYSTEM WITH THE GFS SUPPRESSED TO THE SOUTH OF OUR REGION AND
ECMWF DEPICTING THE NORTHERN EDGE OF THE PRECIP OVER THE SOUTH AND
EAST SECTIONS OF OUR FORECAST AREA. THE MORE NORTHERN EXTENT OF THE
ECMWF PRECIP LIKELY DUE TO THE TROUGH BEING SLIGHTLY MORE AMPLIFIED
COMPARED TO THE GFS. FOR NOW...WILL MAINTAIN CHANCE POPS ACROSS THE
SOUTH AND EAST AND SLIGHT CHANCE POPS ACROSS THE NW. EXTENSIVE CLOUD
COVER AND COOL NLY LOW LEVEL FLOW WILL KEEP HIGH TEMPS SEVERAL
DEGREES BELOW NORMAL. HIGHS THU MID-UPPER 40S.
A S/W RIDGE WILL BUILD INTO OUR REGION BEHIND THE EXITING TROUGH
FRIDAY AND CROSS THE REGION SATURDAY. THIS WEATHER SYSTEM WILL
INITIATE A DRY WEATHER REGIME WITH MODERATING TEMPERATURES. BY
SATURDAY...EXPECT HIGH TEMPS CLOSER TO NORMAL FOR MID JANUARY WITH
HIGHS RANGING FROM UPPER 40S TO AROUND 50 NORTH TO THE LOWER 50S
SOUTH. THE WARMING TREND CONTINUES INTO SUNDAY AS WLY FLOW
DOMINATES. AFTERNOON TEMPS HAVE THE POTENTIAL TO REACH WELL INTO THE
50S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 1255 AM MONDAY...
AVIATION CONDITIONS WILL DETERIORATE ACROSS CENTRAL NC THROUGH 10Z
AS AN AREA OF RAIN MOISTENS THE INITIALLY DRY SUB CLOUD LAYER.
CEILINGS WILL LOWER TO IFR/LIFR ACROSS CENTRAL NC BY 08Z-10Z ALONG
WITH WIDESPREAD RAIN LIMITING THE VISIBILITY 2SM-4SM. THERE WILL BE
POCKETS OF 1SM IN MODERATE/HEAVY RAIN BETWEEN 09Z-15Z.
A LOW LEVEL JET ABOVE THE COOL STABLE AIR MASS AT THE SURFACE IS
FORECAST TO STRENGTHEN OVERNIGHT THROUGH THE DAYLIGHT HOURS THIS
MORNING. THE MODELS DIFFER BY AS MUCH AS 10-15 KTS ON THE STRENGTH
OF THE JET WITH THE NAM MODEL GUIDANCE STRONGER THAN THE GFS. PER
ANALYSIS OFF THE CLAYTON NC WIND PROFILER (WHICH IS DEPICTING WINDS
IN THE 1500-2500FT AGL LAYER 20-25KTS AT 05Z)...THE STRONGER NAM MAY
BE CORRECT. THUS WILL CONTINUE TO MENTION LLWS CONDITIONS BEGINNING
AROUND 09Z AT KRDU...KFAY AND KRWI...PERSISTING UNTIL MID DAY.
THE WIDESPREAD RAIN WILL DIMINISH FROM TEH SW THIS AFTERNOON THOUGH
THE LOW CLOUDS AND AREAS OF DRIZZLE WILL PERSIST. ADVERSE AVIATION
CONDITIONS WITH LOW CLOUDS AND AREAS OF MVFR/IFR FOG/DRIZZLE WILL
OCCUR TONIGHT THROUGH TUESDAY MORNING.
A COLD FRONT WILL MOVE SOUTHWARD ACROSS THE REGION LATE TONIGHT AND
TUESDAY MORNING. THE COLDER AIR BEHIND THIS SYSTEM INTERACTING WITH
THE AVAILABLE MOISTURE MAY CAUSE A PERIOD OF FREEZING DRIZZLE OR
FREEZING LIGHT RAIN TUESDAY NIGHT INTO EARLY WEDNESDAY...LEADING TO
A LIGHT GLAZE ON EXPOSED OBJECTS.
THE ADVERSE AVIATION CONDITIONS OF LOW CLOUDS AND PERSISTENT
DRIZZLE/LIGHT RAIN WILL PERSIST WEDNESDAY AND POSSIBLY INTO
THURSDAY. IMPROVING CONDITIONS ANTICIPATED BY FRIDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...NP/WSS
SHORT TERM...BSD
LONG TERM...WSS
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1012 AM EST MON JAN 12 2015
.SYNOPSIS...
RAIN WILL CONTINUE ACROSS THE CAROLINAS AS A COASTAL FRONT PUSHES
WESTWARD OVER THE COAST WITH SUBTROPICAL AIR SPREADING ONTO THE
BEACHES. COOLER CONDITIONS WILL PERSIST INLAND AS A WEDGE OF
HIGH PRESSURE REMAINS ACROSS THE INTERIOR CAROLINAS. STRONG HIGH
PRESSURE WILL BUILD DOWN INTO THE CAROLINAS LATE MONDAY THROUGH
WEDNESDAY REINFORCING THE WEDGE ACROSS THE CAROLINAS. LOW PRESSURE
WILL DEEPEN OFF THE SOUTHEAST COAST THURSDAY INTO FRIDAY BEFORE
DRIER HIGH PRESSURE RETURNS FOR THE WEEKEND WITH SUNNIER AND
WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM MONDAY...A COASTAL FRONT BISECTS OUR CWA THIS MORNING
WITH TEMPS IN THE MID 60S AT THE BEACHES...AND UPPER 40S/LOWER 50S
FURTHER INLAND TOWARD I-95. THE WARM AND HUMID AIR MASS BEHIND THE
FRONT HAS SUPPORTED SHOWERS AND ISOLATED TSTMS ALONG THE COAST.
ANOTHER ROUND OF SHOWERS IS ALREADY BEGINNING TO FILL IN OVER THE
PEE DEE REGION...AND THE HRRR SHOWS THE WAVE OF MOISTURE AND LOW
PRESSURE OVER THE CHS AREA MOVING INTO OUR CWA OVER THE NEXT COUPLE
HOURS. HAVE MAINTAINED CATEGORICAL POPS THROUGH THE AFTN HOURS AS
SHOWERS AND PERHAPS ISOLATED TSTMS WILL PERSIST FOR MUCH OF THE
DAY. THE FOCUS FOR HEAVIER RAINFALL THIS AFTERNOON SHOULD SHIFT
TOWARD THE COAST...WHERE AN ADDITIONAL HALF INCH OR MORE OF RAIN
IS EXPECTED.
POPS WANE INTO TONIGHT FROM SOUTHWEST TO NORTHEAST AS DRIER HIGH
PRESSURE EXPANDS INTO THE CAROLINAS FROM THE NORTHWEST. THIS WILL
FORCE THE WARM FRONT BACK OFFSHORE AS COOLER AIR FILTERS INTO THE
REGION OVERNIGHT. FORECAST LOWS RANGE FROM LOW TO MID 40S INLAND
TO UPPER 40S AT THE BEACHES.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM MONDAY...STRONG HIGH PRESSURE WILL BUILD DOWN FROM
THE NORTH THROUGH MID WEEK HELPING TO REINFORCE THE WEDGE IN PLACE
ACROSS THE CAROLINAS AND CREATING CLOUDY DAMP AND COOL WEATHER
TUES INTO WED. SHALLOW COOL NE WINDS NEAR THE SFC WILL BE OVERRUN
BY SW WINDS ALOFT HELPING TO LOCK IN LOW CLOUDS AND KEEP CHC OF
RAIN IN THE FORECAST. A SHORTWAVE WILL RIDE ACROSS THE CAROLINAS
OVERNIGHT TUES FURTHER ENHANCING LIFT AND INCREASING THE CHC OF
RAIN. OVERALL EXPECT CLOUDY AND COOL WEATHER WITH INTERMITTENT
RAIN THROUGHOUT THE PERIOD AS WEDGE HOLDS ON ACROSS THE AREA. KEPT
SOME FZ RAIN IN FORECAST FOR A FEW HOURS EARLY WED MORNING AS
TEMPS REMAIN BELOW FREEZING ACROSS THE EXTREME WESTERN REACHES OF
LOCAL FORECAST AREA...WEST OF I95 FOR A FEW HOURS AROUND DAYBREAK.
SHORTWAVE WILL BE MOVING OFF TO THE EAST AT THIS TIME SO RAIN
CHANCES WILL DIMINISH THROUGH THE MORNING HOURS...LEAVING MORE IN
THE WAY OF LOW CLOUDS AND DRIZZLE FOR WED INTO WED NIGHT.
COLD AIR ADVECTION AND CLOUD COVER WILL KEEP TEMPS BELOW NORMAL
THROUGH MID WEEK. HIGH TEMPS WILL STRUGGLE TO MAKE IT OUT OF THE
40S WITH SLIGHTLY WARMER TEMPS CLOSER TO THE COAST. OVERNIGHT
TEMPS WILL BE DOWN IN THE 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...MID TO UPPER TROUGH WILL DIG DOWN FROM THE
GREAT LAKES AS IT MOVES EAST PHASING WITH SOUTHERN STREAM
SHORTWAVE. AS THIS SYSTEM MOVES EAST IT MAY ACT TO DEEPEN LOW
PRESSURE OVER THE SOUTHEAST. THE LATEST MODEL RUNS KEEP LOW
PRESSURE WELL SOUTH AND OFF SHORE. THEREFORE EXPECT BEST CHC OF
PCP TO REMAIN SOUTH OR OVER THE WATERS TO THE EAST...BUT EXPECT
LOW CLOUDS AND LOWER END PCP TO REMAIN OVER FORECAST AREA THROUGH
THURS.
ONCE THIS SYSTEM MOVES EAST THURS NIGHT INTO FRI...DEEP DRY N-NW
FLOW WILL DEVELOP. THIS WILL HELP TO SCOUR OUT ANY LOW CLOUDS AND
PCP PRESENT LEAVING DRIER SUNNIER WEATHER FOR FRI INTO SAT AS HIGH
PRESSURE MOVES OVER THE AREA FROM THE WEST. AIR MASS WILL MODIFY
BY THE WEEKEND AS COOLER NORTHERLY WINDS ON FRI LIGHTEN AND CAA
COMES TO END. COOLER NORTHERLY FLOW ON FRI WILL BE OFFSET BY
INCREASING SUNSHINE ALLOWING TEMPS TO MAKE IT INTO THE 50S MOST
PLACES. SATURDAY WILL BE THE SUNNIEST AND WARMEST DAY WHICH MAY
EXTEND INTO SUNDAY. MODELS ARE HINTING AT ANOTHER WEDGE POSSIBLY
SETTING UP SUN INTO MON BUT FOR NOW...WILL MAINTAIN A SUNNY...DRY
AND WARM FORECAST FOR SUN INTO MONDAY BUT CLOUDS MAY RETURN
ESPECIALLY BY MONDAY.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...A FRONT WILL LIE BETWEEN THE INLAND AND COASTAL
TERMINALS TODAY. LOWEST PREDOMINATE CONDITIONS...LIFR/IFR...WILL BE
WEST OF THE FRONT AT THE INLAND TERMINALS. ON THE EAST SIDE OF THE
FRONT AT THE COASTAL TERMINALS PREDOMINATE MVFR CONDITIONS WILL
DEVELOP...WITH TEMPO IFR POSSIBLE IN CONVECTIVE SHOWERS. FLIGHT
CONDITIONS SHOULD LOWER LATER THIS AFTERNOON TO LIFR/IFR AT THE
COASTAL TERMINALS AS THE FRONT MOVES BACK OFFSHORE.
THUNDERSTORMS WILL BE ISOLATED EARLY TODAY...THUS CONFIDENCE IS LOW
ANY ONE TERMINAL WILL BE AFFECTED. EVEN IF A THUNDERSTORM DOES
OCCUR...DUE TO A VERY RAPID MOVEMENT WOULD EXPECT ONLY VERY BRIEF
VCTS. MAY BE A BRIEF LULL IN CONVECTIVE PRECIPITATION BY 16-18Z.
THE BEST CHANCE OF THUNDERSTORMS SHOULD BE THIS AFTERNOON AT THE
COASTAL TERMINALS WHEN THE BEST LIFT OCCURS AS THE FRONT MOVES BACK
OFFSHORE. AFTER FROPA LIFR/IFR WILL AFFECT THE COASTAL TERMINALS.
THIS EVENING AND OVERNIGHT LIFR BECOMING IFR WITH ONLY A SLIGHT
CHANCE OF ANY IMPROVEMENT TO LOW MVFR.
EXTENDED OUTLOOK...RAIN AND MVFR/IFR CONDITIONS WILL PREVAIL
POSSIBLY THROUGH WED AS A COOL WEDGE REMAINS LOCKED IN PLACE OVER
THE CAROLINAS. RAIN/MVFR ON THU. VFR FRI AND SAT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM MONDAY...THE SMALL CRAFT ADVISORY REMAINS IN EFFECT
THROUGH MIDNIGHT TONIGHT. FRYING PAN SHOALS BUOY 41013 IS CURRENTLY
REPORTING SEAS AROUND 7 FT...WITH SEAS AT BUOY 41108 RUNNING
AROUND 5 FT. HAVE KEPT SEAS IN THE 4 TO 6 FT RANGE THROUGH TODAY
AS SOUTH WINDS 15-20 KT PERSIST OVER THE WATERS. MORE SHOWERS AND
ISOLATED TSTMS CAN BE EXPECTED THIS AFTERNOON AS A WAVE OF LOW
PRESSURE DEVELOPS ALONG THE COASTAL FRONT AND MOVES NORTHWARD.
AFTER MIDNIGHT...HIGH PRESSURE EXPANDING INTO THE CAROLINAS FROM
THE NORTHWEST WILL SHIFT WINDS TO THE NORTHWEST. THIS OFFSHORE
FLOW SHOULD ALLOW SEAS TO RELAX BELOW SCA CRITERIA.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM MONDAY...STRONG HIGH PRESSURE WILL BUILD DOWN FROM
THE NORTH AS COASTAL TROUGH SHIFTS OFF TO THE EAST. THIS WILL
LEAVE STRONGER N-NE WINDS THROUGH MUCH OF THE PERIOD. WINDS WILL
INCREASE FROM 10 TO 15 KT EARLY TUES UP TO 15 TO 25 KTS IN COOL
NORTHERLY SURGE THROUGH LATE TUES INTO WED ENHANCED BY SHORTWAVE
MOVING THROUGH. THEREFORE SEAS DOWN AROUND 3 TO 5 FT EARLY ON
TUES WILL JUMP BACK UP REACHING UP TO 5 TO 7 FT TUES NIGHT WITH
SCA CONDITIONS BACK IN THE FORECAST.
WINDS AND SEAS WILL DIMINISH THROUGH WED AS GRADIENT RELAXES
LEAVING NORTHERLY WINDS AROUND 10 TO 15 KTS AND SEAS DOWN BELOW
SCA THRESHOLDS BY LATE WED INTO THURS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...A SHORTWAVE MOVING IN FROM THE WEST WILL
DEEPEN LOW PRESSURE OVER THE WATERS OF THE SOUTHEAST. THIS SHOULD
HELP TO SHARPEN THE NORTHERLY FLOW INCREASING UP TO 15 TO 20 KTS
LATE THURS INTO FRI AS IT RIDES OFF TO THE EAST LEAVING A DEEP
COOL NORTHERLY FLOW OVER THE WATERS. SEAS AROUND 3 TO 5 FT MAY
SHOOT UP OVER SCA THRESHOLDS THURS NIGHT INTO FRI BEFORE RELAXING
AGAIN HEADING INTO THE WEEKEND AS GRADIENT RELAXES LEAVING NE
WINDS AROUND 10 TO 15 KTS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...BJR
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
MARINE...BJR/RGZ
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
556 AM CST MON JAN 12 2015
.UPDATE...
UPDATED TO ISSUE A DENSE FOG ADVISORY FOR THE SW HALF OF THE CWA.
&&
.DISCUSSION...
UPDATED TO INCLUDE DENSE FOG ADVISORY FOR THE SW HALF OF THE CWA.
LATEST HRRR WHICH SHOWED CLEARING NOW SHOWS VSBY 1/2 MILE OR LESS
THROUGH 15Z. THIS MATCHES UP WELL WITH THE DETERIORATING TREND
WITH THE LATEST OBS, NEW ZONES OUT BY 600 AM. 43
&&
.PREV DISCUSSION... /ISSUED 519 AM CST MON JAN 12 2015/
DISCUSSION...
SEE THE 12Z AVIATION DISCUSSION BELOW.
40
AVIATION...
LIFR CONDITIONS SHOULD SLOWLY LIFT LATER THIS MORNING TO IFR...
AND THEN POSSIBLY MVFR BY MID AFTERNOON. THERE IS SOME INDICATION
THAT THERE WILL BE A BREAK IN THE CEILINGS LATE THIS AFTERNOON...
ESPECIALLY TOWARD THE COAST. HOWEVER...MOST MODEL DATA SHOWS AT
LEAST MVFR CONDITIONS ARE LIKELY AFTER 03Z.
40
PREV DISCUSSION... /ISSUED 413 AM CST MON JAN 12 2015/
DISCUSSION...
AT 3 AM...A WEAK AND RATHER DIFFUSE COLD FRONT EXTENDED FROM ABOUT
LITTLE ROCK TO TYLER TO LUBBOCK. THE LEADING EDGE OF THE COOLER
AIR WILL LAG BEHIND THE FRONT BY SEVERAL HOURS AND WINDS WILL NOT
INCREASE UNTIL EARLY AFTN. YESTERDAYS RAINFALL HAS LEFT THE GROUND
SATURATED AND FOG IS FAIRLY COMMON ACROSS THE AREA. W-NW WINDS
DEVELOPED OVERNIGHT AND THIS SEEMED TO HELP LIFT THE FOG INTO A
LOW CIG. VISIBILITIES HAVE IMPROVED TO 2 TO 4 MILES SO HAVE
CANCELED THE DENSE FOG ADVISORY. WILL WATCH TRENDS SINCE THE
GROUND IS SO WET BUT FEEL THE WEST WIND WILL KEEP VSBYS ABOVE THE
1/4 MILE CRITERIA FOR A DENSE FOG ADVISORY. TEMPS AND SKY COVER
ARE A BIT TRICKY FOR THIS AFTN. THE GFS IS WARMER AND THE GFS
SOUNDINGS SHOW SOME PARTIAL CLEARING THIS AFTN. THE NAM...HRRR AND
RAP KEEP A LOW OVERCAST IN PLACE AND TEMPS ON THE COOL SIDE. FCST
SOUNDINGS SHOW A STRONG INVERSION WITH MSTR TRAPPED BENEATH SO
DON`T THINK THERE WILL BE ENOUGH MIXING TO CLEAR SKIES OUT. WILL
LEAN TOWARD THE RAP/HRRR FOR SKY COVER AND A NAM/ECMWF BLEND FOR
TEMPS.
A STRONG S/WV WILL CROSS THE SOUTHERN PLAINS WED/THURSDAY. WINDS
ALOFT WILL BECOME SW AS EARLY AS TUESDAY AND WEAK ISENTROPIC
UPGLIDE COMMENCE ON TUESDAY. MSTR LEVELS BEGIN TO SLOWLY INCREASE
AND PEAK NEAR 1.00 ON WEDNESDAY AFTN. MSTR LEVELS LOOK SUFFICIENT
FOR SOME LIGHT PRECIP NEAR THE COAST BUT TOO DRY FOR MUCH RAIN
FURTHER INLAND. THE S/WV TROUGH AXIS WILL BE EAST OF SE TX BY
THURSDAY. A CONFLUENT UPPER FLOW AND SUBSIDENCE SHOULD YIELD
CLEARING SKIES ON THURSDAY WITH A BIT OF A WARMING TREND. TEMPS
WILL TREND WARMER THROUGH NEXT WEEKEND WITH HIGHS NEAR 70 BY NEXT
SUNDAY. 43
MARINE...
PATCHY DENSE FOG WAS STILL AROUND GALVESTON BAY AND OFF GALVESTON
ISLAND AT 330 AM. BECAUSE OF THE OBSERVATIONS AND THE FACT THAT
MODEL GUIDANCE AND THE HRRR MODEL STILL FORECAST THE POSSIBILITY FOR
DENSE FOG...KEPT THE DENSE FOG ADVISORY IN PLACE THROUGH 9 AM.
A WEAK COLD FRONT IS STILL FORECAST TO PUSH OFF THE COAST...ALTHOUGH
THE FRONT WAS HARD TO LOCATE IN THE MODEL DATA. HIGH PRESSURE WILL
THEN BUILD OVERHEAD THROUGH THE REMAINDER OF THE WORK WEEK.
40
CLIMATE...
YESTERDAY WAS THE 15TH CONSECUTIVE DAY WITH A DAILY AVERAGE
TEMPERATURE BELOW NORMAL. THE AVG DAILY TEMPERATURE AT HOUSTON DURING
THIS 15 DAY PERIOD HAS BEEN 44.0 DEGREES OR THE 8TH COOLEST 12/28
THRU 01/11. THE COOLEST SUCH PERIOD WAS BACK IN 2009-10 WITH AN
AVERAGE TEMP OF 41.0 DEGREES. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 51 40 47 37 45 / 10 10 10 10 20
HOUSTON (IAH) 53 44 50 39 47 / 10 10 10 10 20
GALVESTON (GLS) 54 46 51 44 48 / 10 10 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
519 AM CST MON JAN 12 2015
.DISCUSSION...
SEE THE 12Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
LIFR CONDITIONS SHOULD SLOWLY LIFT LATER THIS MORNING TO IFR...
AND THEN POSSIBLY MVFR BY MID AFTERNOON. THERE IS SOME INDICATION
THAT THERE WILL BE A BREAK IN THE CEILINGS LATE THIS AFTERNOON...
ESPECIALLY TOWARD THE COAST. HOWEVER...MOST MODEL DATA SHOWS AT
LEAST MVFR CONDITIONS ARE LIKELY AFTER 03Z.
40
&&
.PREV DISCUSSION... /ISSUED 413 AM CST MON JAN 12 2015/
DISCUSSION...
AT 3 AM...A WEAK AND RATHER DIFFUSE COLD FRONT EXTENDED FROM ABOUT
LITTLE ROCK TO TYLER TO LUBBOCK. THE LEADING EDGE OF THE COOLER
AIR WILL LAG BEHIND THE FRONT BY SEVERAL HOURS AND WINDS WILL NOT
INCREASE UNTIL EARLY AFTN. YESTERDAYS RAINFALL HAS LEFT THE GROUND
SATURATED AND FOG IS FAIRLY COMMON ACROSS THE AREA. W-NW WINDS
DEVELOPED OVERNIGHT AND THIS SEEMED TO HELP LIFT THE FOG INTO A
LOW CIG. VISIBILITIES HAVE IMPROVED TO 2 TO 4 MILES SO HAVE
CANCELED THE DENSE FOG ADVISORY. WILL WATCH TRENDS SINCE THE
GROUND IS SO WET BUT FEEL THE WEST WIND WILL KEEP VSBYS ABOVE THE
1/4 MILE CRITERIA FOR A DENSE FOG ADVISORY. TEMPS AND SKY COVER
ARE A BIT TRICKY FOR THIS AFTN. THE GFS IS WARMER AND THE GFS
SOUNDINGS SHOW SOME PARTIAL CLEARING THIS AFTN. THE NAM...HRRR AND
RAP KEEP A LOW OVERCAST IN PLACE AND TEMPS ON THE COOL SIDE. FCST
SOUNDINGS SHOW A STRONG INVERSION WITH MSTR TRAPPED BENEATH SO
DON`T THINK THERE WILL BE ENOUGH MIXING TO CLEAR SKIES OUT. WILL
LEAN TOWARD THE RAP/HRRR FOR SKY COVER AND A NAM/ECMWF BLEND FOR
TEMPS.
A STRONG S/WV WILL CROSS THE SOUTHERN PLAINS WED/THURSDAY. WINDS
ALOFT WILL BECOME SW AS EARLY AS TUESDAY AND WEAK ISENTROPIC
UPGLIDE COMMENCE ON TUESDAY. MSTR LEVELS BEGIN TO SLOWLY INCREASE
AND PEAK NEAR 1.00 ON WEDNESDAY AFTN. MSTR LEVELS LOOK SUFFICIENT
FOR SOME LIGHT PRECIP NEAR THE COAST BUT TOO DRY FOR MUCH RAIN
FURTHER INLAND. THE S/WV TROUGH AXIS WILL BE EAST OF SE TX BY
THURSDAY. A CONFLUENT UPPER FLOW AND SUBSIDENCE SHOULD YIELD
CLEARING SKIES ON THURSDAY WITH A BIT OF A WARMING TREND. TEMPS
WILL TREND WARMER THROUGH NEXT WEEKEND WITH HIGHS NEAR 70 BY NEXT
SUNDAY. 43
MARINE...
PATCHY DENSE FOG WAS STILL AROUND GALVESTON BAY AND OFF GALVESTON
ISLAND AT 330 AM. BECAUSE OF THE OBSERVATIONS AND THE FACT THAT
MODEL GUIDANCE AND THE HRRR MODEL STILL FORECAST THE POSSIBILITY FOR
DENSE FOG...KEPT THE DENSE FOG ADVISORY IN PLACE THROUGH 9 AM.
A WEAK COLD FRONT IS STILL FORECAST TO PUSH OFF THE COAST...ALTHOUGH
THE FRONT WAS HARD TO LOCATE IN THE MODEL DATA. HIGH PRESSURE WILL
THEN BUILD OVERHEAD THROUGH THE REMAINDER OF THE WORK WEEK.
40
CLIMATE...
YESTERDAY WAS THE 15TH CONSECUTIVE DAY WITH A DAILY AVERAGE
TEMPERATURE BELOW NORMAL. THE AVG DAILY TEMPERATURE AT HOUSTON DURING
THIS 15 DAY PERIOD HAS BEEN 44.0 DEGREES OR THE 8TH COOLEST 12/28
THRU 01/11. THE COOLEST SUCH PERIOD WAS BACK IN 2009-10 WITH AN
AVERAGE TEMP OF 41.0 DEGREES. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 51 40 47 37 45 / 10 10 10 10 20
HOUSTON (IAH) 53 44 50 39 47 / 10 10 10 10 20
GALVESTON (GLS) 54 46 51 44 48 / 10 10 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: GALVESTON BAY...WATERS FROM HIGH ISLAND TO FREEPORT
OUT 20 NM.
&&
$$
DISCUSSION...43
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
413 AM CST MON JAN 12 2015
.DISCUSSION...
AT 3 AM...A WEAK AND RATHER DIFFUSE COLD FRONT EXTENDED FROM ABOUT
LITTLE ROCK TO TYLER TO LUBBOCK. THE LEADING EDGE OF THE COOLER
AIR WILL LAG BEHIND THE FRONT BY SEVERAL HOURS AND WINDS WILL NOT
INCREASE UNTIL EARLY AFTN. YESTERDAYS RAINFALL HAS LEFT THE GROUND
SATURATED AND FOG IS FAIRLY COMMON ACROSS THE AREA. W-NW WINDS
DEVELOPED OVERNIGHT AND THIS SEEMED TO HELP LIFT THE FOG INTO A
LOW CIG. VISIBILITIES HAVE IMPROVED TO 2 TO 4 MILES SO HAVE
CANCELED THE DENSE FOG ADVISORY. WILL WATCH TRENDS SINCE THE
GROUND IS SO WET BUT FEEL THE WEST WIND WILL KEEP VSBYS ABOVE THE
1/4 MILE CRITERIA FOR A DENSE FOG ADVISORY. TEMPS AND SKY COVER
ARE A BIT TRICKY FOR THIS AFTN. THE GFS IS WARMER AND THE GFS
SOUNDINGS SHOW SOME PARTIAL CLEARING THIS AFTN. THE NAM...HRRR AND
RAP KEEP A LOW OVERCAST IN PLACE AND TEMPS ON THE COOL SIDE. FCST
SOUNDINGS SHOW A STRONG INVERSION WITH MSTR TRAPPED BENEATH SO
DON`T THINK THERE WILL BE ENOUGH MIXING TO CLEAR SKIES OUT. WILL
LEAN TOWARD THE RAP/HRRR FOR SKY COVER AND A NAM/ECMWF BLEND FOR
TEMPS.
A STRONG S/WV WILL CROSS THE SOUTHERN PLAINS WED/THURSDAY. WINDS
ALOFT WILL BECOME SW AS EARLY AS TUESDAY AND WEAK ISENTROPIC
UPGLIDE COMMENCE ON TUESDAY. MSTR LEVELS BEGIN TO SLOWLY INCREASE
AND PEAK NEAR 1.00 ON WEDNESDAY AFTN. MSTR LEVELS LOOK SUFFICIENT
FOR SOME LIGHT PRECIP NEAR THE COAST BUT TOO DRY FOR MUCH RAIN
FURTHER INLAND. THE S/WV TROUGH AXIS WILL BE EAST OF SE TX BY
THURSDAY. A CONFLUENT UPPER FLOW AND SUBSIDENCE SHOULD YIELD
CLEARING SKIES ON THURSDAY WITH A BIT OF A WARMING TREND. TEMPS
WILL TREND WARMER THROUGH NEXT WEEKEND WITH HIGHS NEAR 70 BY NEXT
SUNDAY. 43
&&
.MARINE...
PATCHY DENSE FOG WAS STILL AROUND GALVESTON BAY AND OFF GALVESTON
ISLAND AT 330 AM. BECAUSE OF THE OBSERVATIONS AND THE FACT THAT
MODEL GUIDANCE AND THE HRRR MODEL STILL FORECAST THE POSSIBILITY FOR
DENSE FOG...KEPT THE DENSE FOG ADVISORY IN PLACE THROUGH 9 AM.
A WEAK COLD FRONT IS STILL FORECAST TO PUSH OFF THE COAST...ALTHOUGH
THE FRONT WAS HARD TO LOCATE IN THE MODEL DATA. HIGH PRESSURE WILL
THEN BUILD OVERHEAD THROUGH THE REMAINDER OF THE WORK WEEK.
40
&&
.CLIMATE...
YESTERDAY WAS THE 15TH CONSECUTIVE DAY WITH A DAILY AVERAGE
TEMPERATURE BELOW NORMAL. THE AVG DAILY TEMPERATURE AT HOUSTON DURING
THIS 15 DAY PERIOD HAS BEEN 44.0 DEGREES OR THE 8TH COOLEST 12/28
THRU 01/11. THE COOLEST SUCH PERIOD WAS BACK IN 2009-10 WITH AN
AVERAGE TEMP OF 41.0 DEGREES. 43
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 51 40 47 37 45 / 10 10 10 10 20
HOUSTON (IAH) 53 44 50 39 47 / 10 10 10 10 20
GALVESTON (GLS) 54 46 51 44 48 / 10 10 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: GALVESTON BAY...WATERS FROM HIGH ISLAND TO FREEPORT
OUT 20 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
406 AM CST MON JAN 12 2015
.SHORT TERM (TODAY THROUGH TUESDAY)...MAIN FORECAST CHALLENGES
FOR TODAY ARE DURATION OF FOGGY CONDITIONS AND WHAT IMPACT FOG WILL
HAVE ON MAX TEMPS. AREAS OF DENSE FOG ARE IMPACTING MOST OF THE
CWA AS OF WRITING /BEGINNING TO DEVELOP VCNTY OF LAREDO/ AND FOG
IS PROG TO CONTINUE TO PERSIST THROUGH AT LEAST MID MORNING. A COLD
FRONT IS PROG TO SLIDE SOUTH ACROSS THE REGION TODAY WITH FOG
LIKELY PERSISTING WELL INTO THE MORNING UNTIL INITIAL WIDESPREAD
PUSH OF NORTHERLY WINDS OCCURS. BIG QUESTION IS WHETHER OR NOT
FOG MIXES OUT COMPLETELY OR SIMPLY TRANSITIONS TO A STRATUS SHIELD
ABOUT 1 KFT OFF THE SURFACE. I AM LEANING TOWARDS A RATHER CLOUDY
DAY ACROSS MOST OF THE AREA /SUNNIER ALONG RIO GRANDE/ DUE TO
MARGINAL WAA AT H85 OVER EXPECTED ARRIVAL OF SHALLOW DENSE AIRMASS
THIS AFTERNOON. AS A RESULT...I HAVE GONE ONE TO TWO CATEGORIES
BELOW GUIDANCE ACROSS EASTERN 2/3 OF THE CWA FOR TODAY/S MAX
TEMPS...BUT POTENTIAL EXISTS FOR A LARGE FORECAST BUST IF
FOG/STRATUS MIXES OUT ALTOGETHER. SHOULD BE NOTED THAT THE LATEST
RUNS OF THE RAP KEEP TEMPS STEADY IN THE 40S THE ENTIRE DAY FOR
ALL BUT THE RIO GRANDE ALONG WITH THICK STRATUS. MOVING BEYOND
TODAY...CLOUD COVER SHOULD CONTINUE TONIGHT AS H5 S/W TROUGH
MOVES EAST OUT OF COAHUILA MX AND A 125 H25 JET STREAK NOSES INTO
THE REGION. THE OVERALL MOISTURE COLUMN WILL BE RATHER
DRY...HOWEVER...AND THUS NO PRECIP IS EXPECTED AT THIS TIME FOR
TONIGHT. MID LEVEL DISTURBANCE KICKS EAST ON TUESDAY WITH WAA
PERSISTING ACROSS SHALLOW COLD AIRMASS. THUS...CONTINUED
CLOUDINESS AND COLDER CONDITIONS EXPECTED WITH MAX TEMPS 15 TO 20
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)...TUESDAY NIGHT THROUGH
WEDNESDAY RAIN CHANCES RETURN WITH ANOTHER UPPER LVL DISTURBANCE
POSITIONED OVER THE NORTHERN MEXICO BORDER TO THE WEST OF THE
STATE. DISTURBANCE OPENS TO A TROUGH AND MOVES EAST OF THE REGION
ON THURSDAY...BRINGING DRIER AIR INTO THE REGION...AND ENDING RAIN
CHANCES. WELL BELOW NORMAL TEMPERATURES CONTINUE THROUGH
WEDNESDAY...BUT A GRADUAL WARMING TREND TAKES OVER FOR THE LATTER
HALF OF THE WEEK. MODERATE OFFSHORE FLOW PERSISTS THROUGH THE MID
WEEK...BECOMING LIGHT ON THURSDAY NIGHT. ONSHORE FLOW FINALLY
RETURNS THEN ON FRIDAY AND WARMER AIR AND MOISTURE RETURN TO THE
REGION. MODELS DIVERGE ON SOLUTIONS FOR THE EXTENDED PERIOD...WITH
THE GFS BRINGING THE NEXT DEEP TROUGH AND UPPER LVL DISTURBANCE
SOUTH DURING THE BEGINNING OF NEXT WEEK...WHILE THE ECMWF KEEPS
RIDGING OVER THE WESTERN AND CENTRAL CONUS DURING THE SAME TIME.
WILL CONTINUE TO MONITOR FOR WHICH WAY SOLUTIONS TREND. EVEN
SO...THIS WEEKEND LOOKS TO BE THE MOST PLEASANT DAYS SOUTH TEXAS
HAS SEEN LATELY...WITH TEMPERATURES WARMING TO THE UPPER 60S TO
LOWER 70S IN THE AFTERNOONS.
&&
.MARINE...DENSE FOG POSSIBLE THROUGH MID MORNING ACROSS AREA BAYS
AND NEARSHORE WATERS. WEAK NW FLOW THIS MORNING WILL STRENGTHEN
THIS AFTERNOON AS A COLD FRONT SLIDES SOUTH ACROSS THE AREA.
NORTHERLY FLOW WILL INTENSIFY TONIGHT AND A SMALL CRAFT ADVISORY
IS IN EFFECT FOR THE NEAR AND OFFSHORE WATERS. WIND SPEEDS WILL
DECREASE IN INTENSITY SLIGHTLY THROUGH THE DAY TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 56 43 50 43 49 / 10 10 10 20 30
VICTORIA 54 40 49 40 46 / 10 10 10 20 20
LAREDO 64 43 50 42 49 / 10 10 10 20 20
ALICE 56 41 49 41 48 / 10 10 10 20 30
ROCKPORT 55 42 50 44 48 / 10 10 10 20 30
COTULLA 61 40 50 40 48 / 10 10 10 20 20
KINGSVILLE 58 42 50 43 49 / 10 10 10 20 30
NAVY CORPUS 56 43 50 46 50 / 10 10 10 30 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
FOLLOWING ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...
JIM WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...
NUECES...REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
GM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 9 AM CST TUESDAY
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.
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING
ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR...
COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...
COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL
OUT 20 NM.
&&
$$
RH/79...SHORT TERM
LK/84...LONG TERM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
315 AM MST MON JAN 12 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM MST MON JAN 12 2015
OVERNIGHT WATER VAPOR LOOP DEPICTED A SPLIT FLOW IN THE MID/UPPER
LEVELS WITH NORTHERN STREAM TROUGHS AFFECTING THE UPPER MIDWEST
AND NORTHERN GREAT BASIN...AND SOUTHERN STREAM TROUGH MOVING
ACROSS THE DESERT SOUTHWEST. WEAK ISENTROPIC LIFT OVER A STALLED
SURFACE BOUNDARY FROM NORTHWEST THROUGH SOUTH CENTRAL WY TO ALONG
THE CO FRONT RANGE WAS PRODUCING EXTENSIVE LOW CLOUD CEILINGS AND
OCCASIONAL LIGHT SNOW OVER MUCH OF THE CWFA. SNOW ACCUMULATIONS
HAVE BEEN AVERAGING AROUND AN INCH OR LESS. TEMPERATURES WERE
MOSTLY IN THE TEENS AND 20S. WINDS WERE VARIABLE LESS THAN 10 KT.
THE LATEST NUMERICAL MODEL DATA MAINTAINS THE SPLIT FLOW PATTERN
THROUGHOUT THE SHORT TERM PERIOD. SOUTHWEST CONUS TROUGH WEAKENS
AS IT TRACKS ACROSS WEST TX/NORTHERN MX DURING THE NEXT 24 HOURS
WITH THE GREAT BASIN TROUGH DEEPENING AS IT PROGRESSES SOUTH
TOWARD THE FOUR CORNERS REGION. THE NORTHERN STREAM FLOW WILL
REMAIN ACTIVE WITH A COUPLE OF SHORTWAVE TROUGHS MOVING SOUTHEAST
FROM SOUTHERN CANADA INTO THE UPPER MIDWEST AND NORTHEAST CONUS.
RATHER STRONG CANADIAN SURFACE RIDGE BUILDS SOUTH AND EAST THROUGH
THE GREAT PLAINS AND MIDWEST DURING THE NEXT 24 HOURS...WHILE THE
SURFACE FRONT REMAINS PARKED ALONG THE FRONT RANGE. ISENTROPIC
LIFT AND ADEQUATE MOISTURE ALOFT WILL KEEP CHANCES FOR LIGHT SNOW
IN THE FORECAST. THERE WILL BE AREAS OF FOG ALONG THE I-80
CORRIDOR THIS MORNING...BECOMING PATCHY THIS AFTERNOON. LIGHT
UPSLOPE SOUTHEASTERLY FLOW WILL MAINTAIN THE LOW CLOUDS THROUGHOUT
THE DAY. HIGH TEMPERATURES TODAY WILL RANGE FROM THE 20S AND 30S
ALONG AND WEST OF THE LARAMIE RANGE TO THE TEENS EAST. HIGHER
CHANCES FOR SNOW WILL OCCUR WEST OF THE LARAMIE RANGE
TONIGHT...WITH PATCHY FOG DEVELOPING FROM THE SOUTHERN LARAMIE
RANGE EAST INTO FAR SOUTHWEST NE. AS THE NEXT TROUGH PASSES SOUTH
OF THE CWFA TUESDAY...LIGHT SNOW WILL CONTINUE TO FALL OVER MUCH
OF SOUTHEAST WY. SNOW WILL TAPER OFF OVER THE SNOWY AND SIERRA
MADRE RANGES TUESDAY EVENING. 36 HOUR SNOW ACCUMULATIONS WILL
RANGE FROM 1 TO 2 INCHES LOWER ELEVATIONS TO 3 TO 6 INCHES OVER
THE MOUNTAINS. TEMPERATURES TUESDAY THROUGH WEDNESDAY WILL
GRADUALLY MODERATE AS INCREASING WESTERLY WINDS PUSH THE SURFACE
BOUNDARY EAST INTO THE PLAINS. THE PRESSURE GRADIENT WILL BE
FAIRLY WEAK...THUS WINDS WILL NOT BE AS STRONG BUT BREEZY AT TIMES
DURING DAYLIGHT HOURS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 AM MST MON JAN 12 2015
A MILD START TO THE EXTENDED FORECAST PERIOD WITH CONTINUED DRY
QUASI-ZONAL FLOW ALOFT. GFS AND ECMWF BOTH SUGGEST H7 TEMPS AROUND
+2 TO +4 DEG ALONG AND EAST OF THE LARAMIE RANGE ON THU AND FRI
WITH GOOD WESTERLY LOW LEVEL DOWNSLOPE TO DRIVE TEMPS HIGHER.
THINKING IT WILL BE WELL ABOVE NORMAL EARLY IN THE PERIOD WITH
LATEST MOS READINGS IN THE 50-55 DEG F RANGE FOR CHEYENNE THROUGH
SAT. TRENDED WARMER...BUT STILL UNCERCUT MOS BY A FEW DEGREES WITH
LINGERING SNOWPACK. THE GFS BRINGS A RATHER POTENT...BUT MOISTURE
STARVED SHORTWAVE INTO EASTERN WY ON THU NIGHT AND FRI. THE ECMWF
ALSO HINTS AT A WAVE WITH RIPPLES IN THE FLOW...BUT NOT NEARLY AS
PRONOUNCED. A SURFACE LOW IS LIKELY TO TRANSLATE TO THE NORTHEAST
OF THE CWA AT THE SAME TIME...SETTING UP STRONG HEIGHT GRADIENTS.
A GAP WIND EVENT COULD BEGIN AS EARLY AS 06Z FRI FOR ARL/BRX AS
THE H85 CAG-CPR GRADIENT APPROACHES 60 METERS IN THE PRESENCE OF
50 TO 60 KT H75 FLOW AND EXCELLENT SUBSIDENCE IN THE WAKE OF A
PASSING SHORTWAVE. SOME HINT AT A SHOT OF WEAK CAA ON FRI NIGHT
WITH SUBSIDENCE TRYING TO MOVE ONTO THE PLAINS. AGREE WITH PREVIOUS
SHIFTS THAT A BORA EVENT WILL BE POSSIBLE. EXPECT WIND HEADLINES
WILL BE NECESSARY IN THE FUTURE. STILL MAJOR DIFFERENCES BETWEEN
THE GFS AND ECMWF CONCERNING THE EVOLUTION OF A STORM SYSTEM MOVING
INTO THE PACIFIC NORTHWEST THIS WEEKEND. THE GFS TRIES TO DIG THIS
ENERGY INTO THE 4 CORNERS REGION ON SUNDAY WITH WIDESPREAD PCPN
DEVELOPING OVER THE CWA BY MONDAY MORNING. THE ECMWF IS CONSIDERABLY
DRIER AS IT HOLDS ONTO A PROGRESSIVE PATTERN...WITH A NUISANCE
CLIPPER-TYPE SYSTEM MOVING ACROSS THE NORTHERN TIER OF THE U.S.
DECIDED TO BUMP UP POPS ACROSS THE BOARD ON SUN NIGHT AND MON GIVEN
CONSISTENT HINTS AT INCREASING PRECIP CHANCES LATE IN THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1020 PM MST SUN JAN 11 2015
LATEST HRRR GUIDANCE USED IN THE 06Z TAFS THIS EVENING. SHOULD SEE
A SOLID IFR/LIFR EVENT FOR KCYS IN NORTHEAST UPSLOPE FLOW AS WELL
AS OUR SOUTHERN NEBRASKA PANHANDLE AIRPORTS. PROLONGED EVENT
EXPECTED AS THE FRONT STALLS OVER THE AREA AND UPSLOPING WINDS
CONTINUE. EXPECT THIS TO LAST THROUGH TUESDAY BEFORE WEST WINDS
RETURN TO SCOUR OUT THE LOW LEVEL MOISTURE.
&&
.FIRE WEATHER...
ISSUED AT 232 AM MST MON JAN 12 2015
COOLER THAN NORMAL TEMPERATURES...HIGH RELATIVE HUMIDITIES AND
NON-CRITICAL FUELS WILL KEEP FIRE WEATHER CONCERNS NEGLIGIBLE THROUGH
MIDWEEK. THERE WILL BE CHANCES FOR SNOW DURING THE NEXT 24 TO 36 HOURS.
WINDS WILL BE BREEZY AT TIMES...ESPECIALLY DURING DAYLIGHT HOURS.
EXPECT WARMER AND DRY CONDITIONS FOR THE LATTER PART OF THIS WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...MAJ
AREA FORECAST DISCUSSION
NWS PUEBLO CO
337 PM MST MON JAN 12 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 238 PM MST MON JAN 12 2015
CURRENTLY...DENSE FOG AND FREEZING DRIZZLE CONTINUE ACROSS EL
PASO COUNTY...FORCED BY WEAK E-SE UPSLOPE FLOW AND AIDED BY A
FAIRLY DEEP FRESH SNOW COVER...ESPECIALLY OVER THE EASTERN HALF OF
THE COUNTY. GIVEN LATEST HRRR PROG OF LOW LEVEL E-SE WINDS
CONTINUING THROUGH THE EVENING...WILL EXTEND TIME OF WINTER WX ADV
INTO MID EVENING. NOT EXPECTING MUCH MORE IN THE WAY OF ICE
ACCUMULATION...BUT WITH MOST OBSERVATION SITES STILL REPORTING
FZDZ...WILL HOLD OFF ON CONVERTING TO A DENSE FOG ADVISORY FOR
NOW...THOUGH ONE MAY BEE NEEDED LATER TONIGHT. ELSEWHERE...WEAK
TROUGH WAS PRODUCING SOME LIGHT SNOW OVER THE EASTERN
PLAINS...WHILE MOUNTAINS HAVE SEEN ONLY A FEW FLURRIES AS MUCH OF
THE AREA IS CURRENTLY BETWEEN WAVES.
OVERNIGHT...UPPER LOW WILL DROP SOUTH THROUGH GREAT BASIN...TAKING
A TRACK SLIGHTLY TO THE WEST OF YESTERDAY`S MODEL SOLUTIONS.
EXPECT SNOW TO BREAK OUT THIS EVENING OVER THE SOUTHWEST MOUNTAINS
THEN SPREAD NORTHWARD THROUGH THE LA GARITAS AND SAWATCH RANGE
BY MIDNIGHT. KEPT THE WARNING IN PLACE FOR THE SAN JUANS...AND
CHANGED WATCH TO AN ADVISORY FARTHER NORTH. EASTERN MOUNTAINS WILL
SEE OCCASIONAL FLURRIES THROUGH THE NIGHT...THEN A STEADIER LIGHT
SNOW BEGINS TOWARD MORNING AS UPWARD MOTION GRADUALLY STRENGTHENS.
ONCE BAND OF SNOW ON THE PLAINS EXITS THE AREA THIS
EVENING...SUSPECT LOWER ELEVATIONS WILL SEE ONLY SOME SOME
FLURRIES/FOG/-FZDZ OVERNIGHT...AS SHALLOW UPSLOPE FLOW WILL BE THE
MAIN MECHANISM DRIVING CLOUDS/PRECIP. NAM HINTS AT SOME DRYING
AFTER 06Z AS LOW/MID LEVEL FLOW TAKES ON A VERY SLIGHT SW
COMPONENT...THOUGH DOUBTFUL IT WILL BE ENOUGH TO SCOUR OUT CLOUDS
AND FOG...THOUGH VISIBILITY MIGHT IMPROVE MARGINALLY. GIVEN
AMOUNT OF CLOUD COVER...NUDGED LOW TEMPS UP SLIGHTLY...ESPECIALLY
EASTERN PLAINS.
TUESDAY...UPPER TROUGH CONTINUES TO DROP SOUTH OR SLIGHTLY
SOUTHWEST INTO ARIZONA...WITH TRACK A LITTLE LESS FAVORABLE FOR
HEAVY SNOW OVER THE EASTERN MOUNTAINS AND PLAINS. CONTINENTAL
DIVIDE WILL STILL SEE PERIODS OF MODERATE/HEAVY SNOW THROUGH THE
DAY AS MOIST S-SW FLOW CONTINUES...WITH LIGHTER AND LESS STEADY
SNOW OVER THE REMAINING MOUNTAINS AND WESTERN VALLEYS. EASTERN
MOUNTAINS WILL SEE SOME LIGHT SNOW THROUGH THE DAY...POSSIBLY
BECOMING A LITTLE HEAVIER LATE IN THE AFTERNOON AS SURFACE THROUGH
700 MB FLOW BECOMES MORE UPSLOPE IN RESPONSE TO FALLING PRESSURE
OVER NWRN NM. I-25 CORRIDOR AND PLAINS MAY STAY DRY MUCH OF THE
DAY...WITH SNOW DEVELOPING LATE IN THE AFTERNOON...ESPECIALLY
FROM SOUTH OF PUEBLO TO THE NM BORDER. MAX TEMPS TO GO NOWHERE
ONCE AGAIN WITH CLOUDS AND SNOW.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 238 PM MST MON JAN 12 2015
TUESDAY NIGHT AND WEDNESDAY...MODELS ARE IN FAIRLY GOOD AGREEMENT ON
TIMING AND LOCATION OF THE UPPER TROUGH THROUGH WED. TUE NIGHT THE
UPPER LOW DROPS SOUTH NEAR THE 4 CORNERS AND CONTINUES DUE SOUTH
INTO S-SE ARIZONA. WED MORNING THIS UPPER LOW WEAKENS AND SLIDES TO
THE EAST ACROSS SOUTHERN NEW MEXICO. THE EC...GFS AND NAM MODELS ARE
ALL INDICATING THIS PATH...WHICH IS A LITTLE TOO FAR SOUTH FOR ANY
LONG-LASTING SIGNIFICANT SNOWFALL EVENT...IF IT HOLDS TOGETHER.
THEREFORE...FINE TUNED THE POP GRIDS SLIGHTLY TO SHOW WIDESPREAD
AREAL COVERAGE OF PCPN TUE NIGHT BEFORE MIDNIGHT...THEN THE FOCUS OF
THE SNOW WILL SHIFT TO THE SOUTH AS THE LOW PULLS SOUTH AND PCPN
BEGINS TAPERING OFF ACROSS THE NORTH. WED MORNING ISOLATED TO LOW
END SCATTERED POPS ARE FORECAST FOR THE SOUTHERN MTS...THEN PCPN
ENDS AND CLOUDS START TO DIMINISH FROM NORTH TO SOUTH THROUGH THE
AFTERNOON. LOOK FOR A COLD NIGHT TUE WITH LOWS IN THE TEENS TO
SINGLE DIGITS...THEN SLIGHTLY WARMER ON WED AS CONDITIONS BEGIN TO
IMPROVE.
WEDNESDAY NIGHT THROUGH SATURDAY...HIGH PRESSURE OVER THE DESERT SW
WILL HELP TO SHUNT MUCH OF THE ACTIVITY NORTH OF COLORADO...KEEPING
THE FORECAST AREA DRY WITH GRADUAL WARMING. TWO DISTURBANCES WILL
CROSS THE NORTHERN ROCKIES...ONE THU NIGHT AND THE OTHER ON
SAT...BUT AT THIS TIME THEY LOOK TOO FAR NORTH TO AFFECT THE CWA.
LOOK FOR COOL NIGHTS WITH AFTN MAX TEMPS IN THE 40S AND 50S FOR THE
PLAINS...30S TO AROUND 40F FOR THE HIGH VALLEYS.
SUNDAY AND MONDAY...ANOTHER STRONGER DISTURBANCE MOVES INTO THE PAC
NW ON SUNDAY. BOTH THE GFS AND EC STILL PAINT DRY WESTERLY FLOW
ALOFT FOR THE STATE BOTH DAYS...BUT THE EXTENDED PROCEDURE KEEPS
WANTING TO INCLUDE ISOLATED POPS FOR THE CENT MTS
INITIALLY...SPREADING TO ALL OF THE MTS FOR MON. AT THIS TIME...SEE
NO STRONG REASON TO STRAY FAR FROM THE PROCEDURE SINCE A SLIGHT
CHANGE IN COURSE FOR THE WEEKEND DISTURBANCE COULD CERTAINLY BROUGHT
ISOLATED SNOW TO OUR MTS. MOORE
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 238 PM MST MON JAN 12 2015
AT KALS...MVFR CIGS ALREADY RETURNING LATE THIS AFTERNOON AND
WILL CONTINUE OVERNIGHT AND THROUGH THE DAY TUESDAY. MAY SEE SOME
FLURRIES AFTER 04Z...THEN A BETTER CHANCE OF SNOW SHOWERS AND
PERIODS OF IFR VISIBILITY 14Z-23Z.
AT KCOS...HAD HOPED SOME LIGHT SNOW WOULD HELP LIFT FOG THIS
AFTERNOON...BUT WITH MAIN AREA OF SNOW NOW WELL EAST OF THE
TERMINAL...EXPECT LIFR CONDITIONS TO PERSIST ALL NIGHT. SOME VERY
LIGHT FZDZ WILL PERSIST THROUGH 02Z-04Z...THOUGH THINK ICE
ACCUMULATIONS WILL BE MINOR. MODEL SOLUTIONS HINT AT SOME DRYING
AND A SUBTLE INCREASE IN VISIBILITY AFTER 06Z-09Z...THOUGH SUSPECT
CONDITIONS WILL STILL STAY LIFR THROUGH THE NIGHT AND INTO THE
MORNING TUES. LIGHT SNOW AND A NORTHEAST WIND WILL DEVELOP TUES
AFTER 16Z-18Z...WHICH SHOULD IMPROVE VIS/CIGS INTO THE IFR
CATEGORY BY MID AFTERNOON.
AT KPUB...AFTER SOME BRIEF MVFR CIGS THIS AFTERNOON...EXPECT CIGS
TO DROP BACK BELOW BKN010 AFTER 00Z...WITH SOME MVFR VIS IN FOG
AND FLURRIES THROUGH THE NIGHT. ON TUE...MVFR CIGS WILL CONTINUE
THROUGH THE DAY...WITH PERIODS OF IFR CIGS/VIS BECOMING MORE
LIKELY IN THE AFTERNOON AS LIGHT SNOW DEVELOPS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING FOR COZ084-
085.
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 11 PM MST
TUESDAY FOR COZ058-060-061-064-066.
WINTER STORM WARNING UNTIL 5 PM MST TUESDAY FOR COZ068.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
401 PM EST MON JAN 12 2015
.SHORT TERM (TONIGHT THROUGH TUESDAY)...SCT-WIDESPREAD SHRA AND
TSTMS ONGOING ACROSS CEN FL ASSOC W S/WV TROUGH MVG ACROSS THE REGION.
THUS FAR COASTAL AREAS FROM TAMPA BAY SOUTH HAVE MISSED OUT AS ALL
THE ACTIVITY HAS REMAINED INLAND SOUTH AND ACROSS THE NORTH. THAT
SAID...THE OUTFLOW BOUNDARY FROM MORNING GULF STORMS HAS BEEN
DRIFTING SE AND HAS GENERATED NEW ACTIVITY ACROSS TAMPA BAY AREA
IN THE LAST HOUR. THIS BOUNDARY IS EXPECTED TO CONTINUE TO FOCUS NEW
DEVELOPMENT AS LARGE SCALE LIFT (SEEN IN H7-H3 Q-VECTORS) ASSOC W/ S/WV
MOVES ACROSS THE REGION AND THE LATEST HRRR SUPPORTS THIS. GIVEN
THIS...HIGH SCT TO LIKELY POPS ARE IN ORDER TONIGHT FAVORING SRN HALF.
LINGERING BOUNDARY AND MOISTURE WILL BE ADEQUATE FOR ISOLD TO SCT
POPS FAVORING SRN AREAS ON TUE BEFORE DRIER AIR FINALLY ARRIVES.
OTHERWISE MAIN ISSUE OVERNIGHT WILL BE FOR POTENTIAL WHICH WILL BE
GREATEST ACROSS NRN AREAS AND NEARSHORE WATERS. DENSE FOG
ADVISORIES MAY BE REQUIRED...ESP FOR WATERS ONCE RAIN DECREASES
ALLOWING BETTER SEA FOG DEVELOPMENT. TEMPS WILL REMAIN WARM AND
WELL ABOVE CLIMO...ESP WRT LOWS. DIURNAL RANGES WILL REMAIN
RELATIVELY SMALL.
&&
.LONG TERM (TUESDAY NIGHT - MONDAY)... AT THE START OF THE LONG
TERM PERIOD...A COUPLE OF SHORTWAVE TROUGHS WILL BE SWINGING
THROUGH THE SOUTHERN CONUS...WITH THE SOUTHERN STREAM OF THE UPPER
LEVEL JET POSITIONED ACROSS TEXAS AND THE NORTHERN GULF OF MEXICO.
AT THE SURFACE...THE REMNANTS OF A WEAK FRONTAL BOUNDARY WELL
EXTEND ACROSS SOUTHERN FLORIDA TRAILING BEHIND A SOMEWHAT
DISORGANIZED AREA OF LOW PRESSURE NORTH OF THE BAHAMAS. THIS WILL
LEAVE BEHIND A MESSY AND STILL SLIGHTLY MOIST ENVIRONMENT OVER THE
FORECAST AREA...WITH A FEW LINGERING SHOWERS POSSIBLE TUESDAY
NIGHT AND INTO WEDNESDAY.
WEDNESDAY NIGHT AND THURSDAY...AS THE NEXT SHORTWAVE ROTATES
THROUGH THE SOUTHERN MISSISSIPPI RIVER VALLEY...A SECONDARY COLD
FRONT WILL PUSH THROUGH THE FLORIDA PENINSULA BRINGING ANOTHER ROUND
OF SHOWERS TO THE AREA ALONG WITH A SLIGHT CHANCE OF THUNDERSTORMS.
MUCH COOLER AND DRIER AIR WILL FILL IN BEHIND THE COLD FRONT WITH
SKIES BECOMING INCREASING CLEAR AS SURFACE HIGH PRESSURE SETS UP
NORTH OF FLORIDA FRIDAY AND SATURDAY. ALTHOUGH THE PUSH OF COLD AIR
BEHIND THE FRONT WILL NOT BE ENOUGH TO PRODUCE FREEZING
TEMPERATURES...THERE WILL AT LEAST BE A BREAK FROM THE ABOVE NORMAL
TEMPERATURES...WITH HIGHS IN THE 60S ON FRIDAY AND LOWS DROPPING
INTO THE 40S ACROSS MOST OF THE FORECAST AREA SATURDAY MORNING. AS
HIGH PRESSURE GETS REINFORCED FROM THE NORTHWEST DURING THE SECOND
HALF OF THE WEEKEND...TEMPERATURES WILL REBOUND TO NEAR NORMAL
SUNDAY AND MONDAY UNDER LIGHT EAST-NORTHEAST FLOW.
&&
.AVIATION...RAIN AREAS WILL PRODUCE IFR-MVFR CONDITIONS THIS AFTN
AND EVEN AT TIME WITH IFR-LIFR CONDITIONS BECOMING MORE WIDESPREAD
ESP NORTH OF I-4 OVERNIGHT. IF ANYTHING...TAFS MAY BE OPTIMISTIC
IN SOME AREAS OVERNIGHT...BUT GIVEN UNCERTAINTY DID NOT WANT TO GO
TOO LOW ATTM.
&&
.MARINE...MAIN ISSUE WILL BE SEA FOG WHICH IS EXPECTED TO DEVELOP
MORE READILY ONCE SHRA MOVE OUT OF THE AREA. DENSE FOG ADVISORIES
MAY BE REQUIRED ESP ACROSS NEARSHORE WATERS FROM TPA NORTHWARD.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 65 75 62 73 / 40 20 20 10
FMY 66 80 64 78 / 70 30 20 10
GIF 64 79 61 73 / 70 30 20 10
SRQ 64 74 61 74 / 70 20 20 10
BKV 61 75 57 73 / 40 20 20 10
SPG 65 74 62 72 / 50 20 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SHORT TERM/AVIATION/FIRE WEATHER...88/GITTINGER
LONG TERM...18/FLEMING
MARINE...05/CARLISLE
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
1136 AM EST MON JAN 12 2015
.UPDATE...BKN LINE OF TSTMS OFF THE COAST IS TRAINING TO THE NE
TOWARD THE NATURE COAST. THESE STORMS ARE ASSOC W/ LEADING EDGE OF
A WEAKENING MID-UPR LEVEL SHORT WAVE TROUGH WHICH WILL MOVE ACROSS
THE REGION LATER TODAY. MORNING SOUNDING SHOWS ABUNDANT MOISTURE
AND A GENERALLY UNSTABLE PROFILE ALTHOUGH THERE IS A WEAK H5 WARM
NOSE ASSOC W/ A THERMAL TROUGH AHEAD OF THE S/WV. THE S/WV IS FORECAST
BRING LARGE SCALE LIFT SEEN IN Q-VECTOR FIELDS AS WELL AS SOME
MODESTLY COOLER MID LEVEL TEMPS WIPING THIS WEAK INVERSION OUT
THIS AFTN. SHIELD OF CIRRUS WILL LIMIT HEATING SOMEWHAT AND WOULD
BE MORE CONCERNING FOR RAINFALL POTENTIAL IF UPR ENERGY WAS NOT A
FACTOR IN CONVECTIVE POTENTIAL. THAT SAID LATEST HRRR DOES SHOW
BETTER CONVECTIVE CELLS DEVELOPING MORE ACROSS CEN AND ERN
PENINSULA LIKELY DUE TO INFLUENCE OF THE CLOUD DECK. ONE CAVEAT TO
NOTE IS THE THE HI-RES MODELS DO NOT HAVE HANDLE ON CURRENT
CONVECTION OFFSHORE AND IT WILL BE INTERESTING TO SEE IF THIS AREA
BEGINS SHIFTING MORE EAST RATHER THAN NE AS STEERING VEERS THIS
AFTERNOON.
FOR THE UPDATE...RAISED POPS TO 70 EVERYWHERE AND ALSO INCLUDED
80 POPS ACROSS NRN NATURE COAST WHERE TRAINING STORMS ARE MOST
LIKELY TO HAVE IMPACT. ALSO INCREASED SKY TO OVC AREA WIDE.
&&
.PREV DISCUSSION... /ISSUED 251 AM EST MON JAN 12 2015/
SHORT TERM (TODAY - TUESDAY)...
WEAK SURFACE BOUNDARY HAS BEEN LIFTING NORTHWARD ACROSS THE REGION
OVERNIGHT WITH A FEW SHOWERS OCCURRING AHEAD OF IT. THERE WAS EVEN
SOME LIGHTNING FOR A TIME OUT OVER THE GULF WATERS WEST OF THE
NATURE COAST. BEHIND THE DEPARTING BOUNDARY...SKIES ARE MOSTLY
CLOUDY BUT LITTLE TO NO RAIN IS FALLING.
SOME AREAS WILL SEE LOW CLOUDS AND FOG FOR A FEW HOURS THIS MORNING
IN VERY MOIST LOW-LEVEL AIRMASS. MEANWHILE A LARGE AREA OF CLOUDS...
SHOWERS...AND EVEN SOME THUNDERSTORMS ARE ADVANCING EASTWARD ACROSS
THE CENTRAL GULF. THE UPPER-LEVEL DISTURBANCE RESPONSIBLE FOR THIS
WEATHER WILL REACH THE FLORIDA PENINSULA THIS AFTERNOON THEN EXIT
INTO THE ATLANTIC THIS EVENING. THIS SHORT-WAVE TROUGH IS FAIRLY
ROBUST AND HAS LOTS OF MOISTURE TO WORK WITH. EXPECT SHOWERS AND
SOME THUNDERSTORMS TO APPROACH THE COAST THIS MORNING...THEN BECOME
MORE NUMEROUS WITH AFTERNOON HEATING OVER THE INTERIOR. THE TIMING
OF THE SHORT-WAVE WILL DETERMINE WHO SEES MOST OF THE RAIN TODAY...
BUT IT APPEARS OUR COASTAL LOCATIONS COULD BE ON THE VERY EDGE OF
THE HEAVIER RAINS LATER THIS AFTERNOON AS THE SHORT-WAVE CROSSES THE
STATE. THIS WOULD PUT HIGHER RAIN CHANCES INLAND...WHERE WE COULD
SEE A QUARTER TO PERHAPS A HALF INCH OF RAINFALL TODAY.
AFTER DOING SOME EXTENSIVE ANALYSIS OF VARIOUS MODEL FORECAST
SOUNDINGS FOR TODAY...I CAME TO THE CONCLUSION THAT STRONG
THUNDERSTORMS ARE NOT ALL THAT LIKELY. THE ONLY MODEL SHOWING
MARGINALLY SUFFICIENT CAPE AND SHEAR IN PLACE IS THE NAM. IT WAS
ALSO THE MOST ROBUST MODEL YESTERDAY. THE NAM HAS TRENDED WEAKER
SINCE YESTERDAY...AND APPEARS TO BE SLOWLY COMING IN LINE WITH THE
REST OF THE GLOBAL MODELS SHOWING WEAKER LAPSE RATES ALOFT.
THE UPPER-LEVEL DISTURBANCE MOVES AWAY TONIGHT AND TAKES MOST OF THE
RAIN WITH IT. LOTS OF MOISTURE WILL BE LEFT OVER SO LOW CLOUDS AND
FOG ARE LIKELY AGAIN. SOME SHOWERS COULD LINGER THROUGH THE EARLY
EVENING HOURS AS WELL.
ANOTHER WEAK IMPULSE MOVES ACROSS THE REGION ON TUESDAY...BUT THIS
ONE WILL NOT HAVE AS MUCH VIGOR AS ITS PREDECESSOR. STILL...THERE
WILL BE ENOUGH MOISTURE FOR AT LEAST A FEW SHOWERS...AND SKIES WILL
RANGE FROM PARTLY TO MOSTLY CLOUDY ALL DAY.
TEMPERATURES WILL RUN 5 TO 10 DEGREES ABOVE NORMAL THROUGH TUESDAY.
LONG TERM (TUESDAY NIGHT-SUNDAY)...
AN U/L RIDGE WILL PERSIST ALONG THE WEST COAST OF THE U.S. WITH A
MEAN TROUGH EXTENDING FROM THE UPPER MISSISSIPPI VALLEY TO THE FOUR
CORNERS REGION. PATTERN CHANGE EVOLVING AS S/W ENERGY IN THE BASE
OF THE TROUGH OVER THE DESERT SOUTHWEST EJECTS ACROSS THE SOUTHERN
PLAINS WEDNESDAY...COMING IN PHASE WITH A NORTHERN STREAM
DISTURBANCE. THE COMBINED U/L TROUGH WILL APPROACH THE EASTERN
SEABOARD LATE THURSDAY AND THURSDAY NIGHT. IN ITS WAKE ZONAL FLOW
WILL DEVELOP ACROSS THE CONUS WITH A WEAK FAST MOVING DISTURBANCE
TRACKING FROM THE ROCKIES TO THE OHIO RIVER VALLEY FRIDAY AND
SATURDAY. ON SUNDAY...U/L ENERGY WILL DIG OVER THE INTERMOUNTAIN
WEST INDUCING RIDGING DOWNSTREAM WITH THE SUBTROPICAL RIDGE OVER THE
CARIBBEAN NOSING NORTH OVER THE GULF OF MEXICO AND FLORIDA.
AT THE SURFACE...HIGH PRESSURE WILL EXTEND FROM THE NORTHEAST U.S.
TO THE CENTRAL PLAINS WEDNESDAY WITH A FRONTAL BOUNDARY ACROSS THE
CENTRAL FLORIDA PENINSULA AND NORTHERN GULF COAST. AN U/L TROUGH
AND ASSOCIATED S/W DISTURBANCE WILL OVERRUN THE FRONT ON THURSDAY
WITH INCREASING SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE GULF
OF MEXICO...PUSHING EAST OVER WEST CENTRAL AND SOUTHWEST FLORIDA
LATE THURSDAY AND THURSDAY NIGHT. THE FRONTAL BOUNDARY WILL PUSH
SOUTH OF THE REGION THURSDAY NIGHT AS SURFACE HIGH PRESSURE BUILDS
OVER THE LOWER MISSISSIPPI VALLEY AND FLORIDA WITH DRIER COOLER AIR
ADVECTING ACROSS THE FORECAST AREA ON BREEZY NORTH WINDS. THE
SURFACE HIGH WILL MOVE TO THE MID ATLANTIC COAST SUNDAY WITH
BOUNDARY LAYER WINDS ACROSS THE FLORIDA PENINSULA VEERING TO THE
EAST. THIS WILL BEGIN TO MODIFY THE AIRMASS OVER THE FORECAST AREA
WITH A SLIGHT INCREASE IN LOW LEVEL MOISTURE AND MODERATING
TEMPERATURES.
AVIATION...
MVFR AND IFR CEILINGS ARE EXPECTED AT AREA TERMINALS THROUGH THE
MORNING HOURS WITH SOME IMPROVEMENT DURING THE AFTERNOON. SHOWERS
AND EVEN A FEW THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON...BUT
CONFIDENCE IN TIMING AND EXTENT TOO LOW FOR MORE THAN JUST VCTS.
MORE LOW CLOUDS AND FOG IS EXPECTED TONIGHT.
MARINE...
AN UPPER-LEVEL DISTURBANCE WILL BRING SHOWER AND THUNDERSTORM
CHANCES TO THE WATERS TODAY. OTHERWISE GENERALLY BENIGN CONDITIONS
ARE EXPECTED UNTIL A COLD FRONT MOVES APPROACHES OUR WATERS LATE
THURSDAY AND MOVES THROUGH OUR WATERS THURSDAY NIGHT. GUSTY WINDS
AND ROUGH SEAS ARE POSSIBLE THURSDAY NIGHT AND FRIDAY.
FIRE WEATHER...
HIGH HUMIDITY WILL BE WITH US FOR A FEW DAYS. SMOKE DISPERSIONS WILL
BE ON THE POOR SIDE TODAY...OTHERWISE NO SIGNIFICANT FIRE WEATHER
ISSUES EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 77 64 75 64 / 70 30 20 20
FMY 80 65 80 65 / 60 30 20 20
GIF 78 62 77 62 / 70 50 30 10
SRQ 76 62 75 63 / 70 30 20 10
BKV 77 58 76 61 / 70 40 20 20
SPG 76 64 74 64 / 70 30 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION/FIRE WEATHER...88/GITTINGER
MARINE...74/WYNN
DECISION SUPPORT...18/FLEMING
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 AM CST MON JAN 12 2015
.SHORT TERM...
312 AM CST
THROUGH TONIGHT...
THE MAIN FOCUS WILL BE WORKING PRECIP OUT OF THE AREA THIS
MORNING FOLLOWED BY LAKE EFFECT SNOW SHOWER POTENTIAL THIS AFTERNOON
THROUGH TONIGHT. WATER VAPOR IMAGERY SHOWS A PRIMARY UPPER LEVEL
TROUGH AXIS MOVING SOUTHEAST ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY. ANOTHER SMALLER SCALE UPPER TROUGH IS MOVING EAST INTO
NORTHERN ILLINOIS. AT THE SURFACE...A COLD FRONT IS MOVING ACROSS
THE CWA. RADAR MOSAIC SHOWS PRECIPITATION STEADILY MOVING
NORTHEASTWARD WITH THE BACK EDGE MAKING GRADUAL SOUTHEAST PROGRESS.
SOUTHEAST PROGRESS WILL LIKELY INCREASE IN SPEED THROUGH THE MORNING
AS EACH OF THE UPPER TROUGHS CONTINUE EAST AND SOUTHEAST. IT ALSO
APPEARS THAT THE MAIN FRONTOGENETICAL BAND ON THE NORTHERN EDGE WILL
BE WEAKENING OVER THE NEXT FEW HOURS ALLOWING PRECIP TO DECREASE IN
COVERAGE ACROSS CENTRAL AREAS. MOST OF THE SOUTHERN CWA HAS CHANGED
OVER TO SNOW BUT SOUTHERN PORTIONS OF THE ADVISORY AREA ARE PROBABLY
STILL SEEING A MIX. WILL HOLD ONTO THE ADVISORY FOR NOW GIVEN THAT
PRECIP WILL STILL BE FALLING FOR A FEW HOURS BUT AM THINKING IT MAY
BE ABLE TO BE CANCELLED A LITTLE EARLY. THE PASSAGE OF THE INITIAL
UPPER TROUGH AND SURFACE COLD FRONT WILL ALLOW COLDER AIR TO SPREAD
ACROSS THE AREA THROUGH THE AFTERNOON...WITH THE MAIN TROUGH AXIS
BRINGING A BETTER PUSH LATE IN THE DAY. WILL LIKELY SEE A SITUATION
WHERE MANY AREAS SEE THEIR DAYTIME HIGH TEMP THIS
MORNING...ESPECIALLY SOUTH AND EAST...WITH NORTHWEST AREAS POSSIBLY
WARMING A FEW DEGREES THIS AFTERNOON. EXPECT AFTERNOON TEMPERATURES
IN THE LOWER TEENS NORTHWEST TO AROUND 20 SOUTHEAST.
LAKE EFFECT AND TEMPS TONIGHT...WITH STRONG HIGH PRESSURE MOVING
INTO THE UPPER MISSISSIPPI RIVER VALLEY...WINDS WILL TURN NORTHERLY
BEHIND THE PASSING COLD FRONT. THIS WILL SET UP A LONG FETCH DOWN
LAKE MICHIGAN LEADING TO CONVERGENCE AS THERMAL PARAMETERS BECOME
MORE FAVORABLE FOR LAKE EFFECT. LAKE TO H85 DELTA T`S INCREASE TO
-17 TO -18C LATE THIS AFTERNOON. EQUILIBRIUM LEVELS PEAK AROUND 6500
FT LATE THIS AFTERNOON AND EARLY THIS EVENING THEN LOWER TO AROUND
4000 FT INTO THE EARLY OVERNIGHT. WINDS WILL START OUT DUE NORTH
THEN STEADILY SHIFT NORTHEAST THROUGH THE EVENING THEN EAST
OVERNIGHT. HAVE SEEN LAKE EFFECT SNOW SHOWERS SET UP WITH LESS
FAVORABLE PARAMETERS IN LONG FETCH SITUATIONS THIS SEASON BUT THE
STEADY SHIFT TO NORTHEAST WINDS AND SHORTENING OF THE FETCH WILL
LIKELY LIMIT THE DURATION. COVERAGE WILL ALSO BE SOMEWHAT UNCERTAIN.
TIMING WILL BE A BIT TRICKY BUT EXPECT THAT AT LEAST A LOOSELY
ORGANIZED BAND OR BANDS TO DEVELOP LATER THIS MORNING ACROSS THE
EASTERN PART OF THE LAKE WITH BETTER ORGANIZATION INTO THE
AFTERNOON. PORTER COUNTY MAY BE AFFECTED BY LATE MORNING WITH
INCREASING CHANCES THROUGH THE AFTERNOON AS CONVERGENCE FOCUSES AND
THERMAL PARAMETERS IMPROVE. LAKE COUNTY INDIANA WILL BE FAVORED BY
EVENING IF NOT A LITTLE SOONER AS WINDS START TO COME AROUND. THE
BAND SHOULD STEADILY SHIFT WESTWARD THROUGH THE EVENING AFFECTING
EASTERN COOK COUNTY EARLY TO MID EVENING. THE FETCH SHORTENS BEYOND
THAT SO COVERAGE AND INTENSITY SHOULD QUICKLY DROP OFF. A POTENTIAL
WILD CARD WOULD BE IF A MESO LOW CAN DEVELOP WHICH COULD ACT TO
PROLONG ACTIVITY SOMEWHAT BUT INVERSION HEIGHTS WILL BE FALLING AS
HIGH PRESSURE BUILDS IN SO ACTIVITY WOULD LIKELY BE MINIMAL
OVERNIGHT IF THIS DID OCCUR. WILL GO AHEAD AND INCREASE POPS TO LOW
END LIKELY LATE THIS AFTERNOON AND EARLY THIS EVENING...PRIMARILY
ALONG THE COOK/LAKE INDIANA BORDER AND MUCH OF NORTHERN LAKE
COUNTY...WITH HIGH CHANCE FOR SURROUNDING AREAS. WITH SOME
UNCERTAINTY ABOUT COVERAGE AND INTENSITY AM HESITANT TO RAISE BEYOND
THAT AT THE MOMENT. GIVEN THE UNCERTAINTY IN COVERAGE CONFIDENCE IN
SNOW AMOUNTS IS LIMITED BUT THE PROGRESSIVE EAST TO WEST MOVEMENT OF
ANY ACTIVITY AND LIMITED INVERSION HEIGHTS WOULD LIKELY LIMIT
ACCUMULATIONS. WINDS WILL WEAKEN OVERNIGHT BUT MAY NOT COMPLETELY
DROP OFF...BUT WESTERN AREAS WILL LIKELY FALL TO AROUND 0 WITH AREAS
TO THE EAST SEEING TEMPS IN THE SINGLE DIGITS...WITH WARMER READINGS
IN THE IMMEDIATE CHICAGO METRO AND POINTS NORTH THANKS TO FLOW OFF
THE LAKE.
MDB
&&
.LONG TERM...
312 AM CST
TUESDAY THROUGH SUNDAY...
TUESDAY THROUGH THURSDAY...HIGH PRESSURE WILL BE STRETCHED ACROSS
THE GREAT LAKES AND ST. LAWRENCE VALLEY BY TUESDAY. A MUCH FLATTER
UPPER FLOW WILL BE IN PLACE ALLOWING MID LEVEL TEMPS TO MODIFY BUT
WINDS WILL BE LIGHT LIMITING MIXING. WILL CONTINUE WITH HIGHS IN THE
MID TO UPPER TEENS. THE CENTER OF THE HIGH WILL SHIFT EAST TUESDAY
NIGHT BUT A RIDGE AXIS WILL REMAIN ACROSS THE AREA ALLOWING FOR A
DECOUPLING OF WINDS SETTING UP STRONG RADIATIONAL COOLING POTENTIAL.
AN UPPER LEVEL TROUGH WILL BE MOVING ACROSS THE UPPER MISSISSIPPI
RIVER VALLEY AND MAY SPREAD HIGHER LEVEL CLOUD COVER IN LATE WHICH
MAY LIMIT MAXIMUM COOLING POTENTIAL. AT THIS POINT WILL STICK WITH
LOWS MOSTLY IN THE SINGLE DIGITS BELOW ZERO WITH A STEADY OR WARMING
TREND OVERNIGHT POSSIBLE. A SLOWER PROGRESSION OF THE UPPER TROUGH
TO THE NORTHWEST COULD LEAD TO SLIGHTLY COLDER TEMPS OVERNIGHT WITH
A LONGER COOLING PERIOD. THE UPPER TROUGH PASSES WEDNESDAY AND WILL
PROBABLY ONLY RESULT IN AN INCREASE IN CLOUD COVER GIVEN THE
RESIDUAL LOW LEVEL DRY AIR FROM THE DEPARTING SURFACE HIGH. MILDER
LOW/MID LEVEL TEMPS SHOULD ALLOW FOR A DECENT RECOVERY OF TEMPS INTO
THE UPPER TEENS TO NEAR 20. ANOTHER SYSTEM WILL MOVE ACROSS SOUTHERN
CANADA THURSDAY BRINGING ADDITIONAL MODIFICATION OF LOW AND MID
LEVEL TEMPS WITH A STEADIER SOUTHWEST LOW LEVEL FLOW SUPPORTING MID
20S FOR HIGHS. PRECIP FROM THIS SYSTEM LOOKS TO STAY NORTH BUT HAVE
SEEN THESE NORTHERN SYSTEMS HAVE A TENDENCY TO TRACK FURTHER SOUTH
IN RECENT WEEKS SO WILL NEED TO WATCH THAT POTENTIAL IN THE COMING
DAYS.
FRIDAY THROUGH SUNDAY...WESTERN UPPER RIDGING WILL SPREAD
EASTWARD BUT DE-AMPLIFY LATE IN THE WEEK. THIS WILL EVOLVE INTO A
MORE ZONAL FLOW PATTERN INTO THE WEEKEND BUT THE NORTHERN PORTION
OF THE FLOW WILL BE ACTIVE. THE MAIN BAROCLINIC ZONE LOOKS TO
REMAIN TO THE NORTH KEEPING THE LOCAL AREA ON THE SOUTHERN FRINGE
OF ANY SYSTEMS INTO THE WEEKEND. MEDIUM RANGE GUIDANCE IS NOT IN
GREAT AGREEMENT BUT DOES POINT TOWARDS SOME AMPLIFICATION OF THE
FLOW EARLY NEXT WEEK. A MILDER PERIOD WILL RESULT FROM THE MORE
ZONAL PATTERN WITH HIGHS IN THE 30S FRIDAY THROUGH SUNDAY.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* GUSTY NORTH WINDS WITH SUSTAINED WINDS AROUND 15 KT AND MAX
GUSTS ARND 20-23 KT THROUGH THE AFTERNOON. WINDS TURNING
NORTHEAST THIS EVENING THAN EAST TUESDAY.
* MVFR CIGS RETURNING LATER THIS AFTERNOON AND OVERNIGHT.
* CHANCE OF LAKE EFFECT SNOW THIS EVENING.
KMD
//DISCUSSION...UPDATED 18Z...
MVFR CIGS FROM EARLIER THIS MORNING ARE PUSHING SOUTH AND EAST OF
THE AREA THIS MORNING...CURRENTLY ALONG A LINE FROM KGYY TO KIKK
AND TERMINALS SOUTHEAST. MVFR CLOUDS ARE ALSO OVER THE LAKE AND
SHOULD START TO PROGRESS INLAND THROUGH THE AFTERNOON...QUITE
POSSIBLY SOONER THEN THE CURRENT TAFS INDICATE FOR KORD AND KMDW.
MEANWHILE...BREEZY NORTH WINDS CONTINUE TODAY AND MAY CREATE
DRIFTING SNOW...ESPECIALLY ON EAST- WEST RUNWAY CONFIGURATIONS.
LAKE EFFECT SNOW SHOWERS ARE EXPECTED IN NORTHWEST INDIANA THIS
AFTERNOON AND SHIFTING INTO NORTHEAST ILLINOIS THIS EVENING
OVERNIGHT. LOOKS LIKE FLURRIES OR VERY LIGHT SNOW SHOWERS UNTIL
LATER THIS EVENING AND POSSIBLY OVERNIGHT AS NE WIND ORIENTATION
AND BETTER LOW LEVEL LAPSE RATES OCCUR IN THE COLDER AIR
MASS...BUT DON`T EXPECT SHOWERS EVERYWHERE. LOW CONFIDENCE ON
WHERE SNOW SHOWERS WILL OCCUR AND TIMING...BUT ACCUMULATIONS
SHOULD GENERALLY BE A DUSTING WHERE ANY SNOW FALLS WITH HIGHER
AMOUNTS POSSIBLE IN LAKE COUNTY ILLINOIS CLOSER TO KUGN. HANDLED
WITH WITH 6SM -SHSN WITH TEMPO FOR 5SM AS IT WILL LIKELY BE
FLURRIES INITIALLY WITH A BETTER CHANCE FOR SHOWERS LATER IN THE
EVENING...BUT AGAIN CONFIDENCE IS LOW ON SPECIFIC TERMINAL IMPACTS.
KMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH IN WIND TRENDS.
* HIGH IN MVFR CIGS...BUT LOW-MEDIUM ON TIMING OF ARRIVAL AND CLEARING.
* MEDIUM IN LAKE EFFECT SNOW OCCURRING THIS EVENING AND ITS
ASSOCIATED IMPACTS.
KMD
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR. LIGHT AND VARIABLE WINDS BECOMING SOUTHWEST.
WEDNESDAY AND THURSDAY...VFR. WEST TO SOUTHWEST WINDS.
FRIDAY AND SATURDAY...VFR. SOUTHWEST WINDS.
SUNDAY...SLIGHT CHANCE OF RAIN OVERNIGHT. EAST WINDS.
JEE
&&
.MARINE...
217 AM CST
SMALL CRAFT ADVISORY...ONLY CHANGE MADE TO THE SMALL CRAFT IS
EXTENDING IT TO MID TUESDAY MORNING ALONG THE IL NSH WATERS. ICE
COVERAGE WAS NOT SOLID SO THINKING HIGH WAVES FROM THE ONSHORE FLOW
WILL REACH THE IL NSH WATERS. THE WAVES WILL BE HAZARDOUS TO SMALL
CRAFT SO EXTENDED THE IL SMALL CRAFT ADVISORY TO ACCOUNT FOR THE
WAVES.
A WEAK SURFACE TROUGH IS OVER THE LAKE EARLY THIS MORNING WITH A
COLD FRONT STRETCHING FROM NORTH CENTRAL MICHIGAN THROUGH WAUKEGAN
IL. THE COLD FRONT WILL CONTINUE SOUTHEAST WITH NORTHWEST WINDS
BECOMING NORTH AND INCREASING TO 30 KT BY LATE THIS MORNING. WINDS
DIMINISH AND VARY FROM NORTH TO NORTHEAST THIS EVENING AND BECOME
MORE CHAOTIC AS HIGH PRESSURE MOVES OVERHEAD TONIGHT. BY TUESDAY
MORNING EXPECTING EAST WINDS OVER THE SOUTHERN HALF OF THE LAKE AND
NORTHWEST WINDS OVER THE NORTHERN HALF. THE HIGH SLOWLY SHIFTS SOUTH
ALLOWING WINDS TO BECOME SOUTHWEST ACROSS THE LAKE TUESDAY NIGHT.
THE PRESSURE GRADIENT TIGHTENS OVER THE NORTHERN END OF THE LAKE
TOMORROW NIGHT AND WINDS INCREASE TO 15 TO 25 KT. WINDS DIMINISH
AND BECOME WEST WEDNESDAY.
ANOTHER LOW PASSES OVER ONTARIO WEDNESDAY NIGHT INTO THURSDAY WITH
SOUTHWEST TO WEST WINDS INCREASING TO 15 TO 25 KT WEDNESDAY NIGHT.
HIGH PRESSURE FOLLOWS THE LOW FRIDAY ALLOWING WEST WINDS TO DIMINISH
AND THEN BECOME SOUTH BEHIND THE HIGH LATE FRIDAY. THE NEXT LOW
MOVES OVER SOUTHERN MANITOBA FRIDAY NIGHT AND INCREASES THE PRESSURE
GRADIENT OVER THE LAKE. SOUTHWEST WINDS INCREASE TO 15 TO 25 KT AND
THEN DIMINISH SATURDAY NIGHT AS THE LOW MOVES OVER QUEBEC.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 4 AM TUESDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 AM TUESDAY.
&&
$$
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
1149 AM CST Mon Jan 12 2015
.UPDATE...
ISSUED AT 1040 AM CST MON JAN 12 2015
Winter weather advisory was allowed to expire at 9 am from Lincoln
south as light precipitation has ended over central IL. Could
still see some flurries over southeast IL into midday. Some
blowing snow is also possible the rest of today from I-72 north
where 1-3 inches of snow fell last night and have brisk northerly
winds gusting 20-30 mph. Temperatures will continue to fall as
polar air mass moves in behind a cold front that is moving into nw
KY late this morning. Temps currently range from upper teens nw of
IL river by Galesburg to mid 30s far se at Lawrence county. Have
made some adjustments to temps today as mercury levels by sunset/5
pm will drop into the teens across central IL and 20s over
southeast IL. Wind chills will lower to between zero and 5 below
zero over nw counties from I-55 nw by sunset. Low clouds have
pushed se to a Champaign to Taylorville line at late morning and
will continue to decrease this afternoon over southeast IL. Strong
1048 mb arctic high pressure over eastern ND will settle into IA
by dawn Tue and fair but bitter cold back into central/se IL.
&&
.SHORT TERM...(Today)
ISSUED AT 341 AM CST MON JAN 12 2015
No changes planned to the winter weather advisory with the 4 am
package. We will just clear out the western counties as precip ends
and conditions warrant as the morning progresses. The back edge of
the precip is becoming more diffuse, but another trailing band of
snow is still approaching from SE Iowa and N Missouri. Forecast
soundings show we will be losing our ice crystals aloft this
morning, which could cause the light snow to change to freezing
drizzle. Over the next 3-5 hours, we could see a few tenths of an
inch of snow accumulate from the band of snow from Jacksonville to
Bloomington progressing east. The dual pol radar images show the
precip change to all snow clearly, with the leading edge of snow
from Springfield to northwest Champaign county at 09z/3am. Just
ahead of the change-over from rain to snow, there have been reports
of freezing rain and sleet from Champaign to Taylorville, so some
light glazing will still be possible before the rain changes to
completely to snow.
Areas southeast of I-70 could see temps hold just above freezing
until sunrise, and then remain hovering just above freezing until
later morning behind the cold front. So precip would just change
from rain to snow. The main freezing conditions in that area would
be due to the frozen ground freezing rain on untreated surfaces.
Falling temps are expected this afternoon across the board, as NW
winds of 15 gusting to 25 mph usher our next wave of unseasonably
cold air. The HRRR is advertising a rapid clearing of clouds this
morning from NW to SE, which seems a little ahead of satellite
trends. We will delay clearing until later morning in the west, then
progress to all but the far southeast this afternoon.
&&
.LONG TERM...(Tonight through Sunday)
ISSUED AT 341 AM CST MON JAN 12 2015
Tonight the weather quiets down again with high pressure building
back into the Midwest and controls the weather through the week.
Roughly mid week as a synoptic wave digs into the desert SW, flow
over the eastern half of the country moves from more zonal to a more
amplified pattern. Northwesterly flow over the region will move a
short wave through the region as well... and although the models are
currently dry under the surface ridge...will need to watch the
strength of the wave and its persistence for some flurry potential
Wednesday afternoon/evening. Other than that...temps this week
starting out below normal but slowly warming through the end of the
week as more southwesterly flow at the sfc maintains WAA through the
forecast. Next system is starting to have some issues with
consistency for the weekend. Prev GFS originated the system out of
the SW, a result of the bigger wave from earlier in the week. The
most recent ECMWF is weaker with the southern stream/wave...and
instead, develops the sfc system from a shortwave moving across the
nrn tier of the country. With perpetual waa ahead of the system,
have maintained the precip for Sun night and into Monday for rain.
But, with the details so divergent at this point, keeping the
forecast conservative. A more northerly stream system may end up
with more of a precip type decision as the time approaches. A
little too early to call and expect some variability.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1145 AM CST MON JAN 12 2015
MVFR clouds have shifted se of the central IL airports by late
morning with the clearing line se of Taylorville to Danville line.
However some lake effect clouds around 2k ft off Lake MI from
gusty NNE winds 15-25 kts drifting south toward Champaign and
Vermilion cuonties could affect CMI from into mid afternoon. These
gusty winds will cause some blowing snow at times especially at
BMI and CMI where vsbys could briefly be reduced to MVFR. Winds veer
NNE and eventually NE and diminish to around 10 kts or less during
the night and models show low clouds drifting sw toward I-74 by
overnight from southern Lake MI. Think these low clouds will scatter
out during overnight as they move inland toward I-74 airports and
have scattered 2500 ft with BMI and ne having best chance of
seeing broken ceiling. Fair weather expected into Tuesday as
scattered cirrus clouds arrive Tue morning. This due to strong
1049 mb arctic high pressure near the Dakotas/MN border that
drifts into the Great Lakes and northern IL by 18z/noon Tue.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...07
SHORT TERM...Shimon
LONG TERM...HJS
AVIATION...07
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1254 PM EST MON JAN 12 2015
.AVIATION...
WITH THE LAST OF THE SNOW EXITING SOUTHERN MICHIGAN...ATTENTION
TURNS TO MVFR CIGS AND GUSTY WINDS FOR THE AFTERNOON. ARCTIC AIR
FILLING IN BEHIND THE EXITING SYSTEM HAS BROUGHT NW WINDS GUSTING UP
TO 20 KNOTS TO THE AREA. OBSERVATIONS ARE SHOWING CIGS TO BE QUITE
VARIABLE ACROSS THE REGION BUT GENERALLY COMING IN AS MVFR. AS DRIER
AIR WORKS INTO THE AREA THROUGH THE EVENING...THE CLOUDS WILL BECOME
VFR THEN SCATTER OUT. HIGH PRESSURE BUILDING INTO THE REGION WILL
PROVIDE FOR MOSTLY CLEAR SKIES ON TUESDAY.
FOR DTW...WINDS WILL BE ELEVATED THIS AFTERNOON GUSTING TO 20 KNOTS
OUT OF 350 DEGREES. QUESTION COMES INTO PLAY FOR TONIGHT AS TO
WHETHER MOISTURE ADVECTING INTO THE THUMB OFF LAKE HURON WILL MAKE
IT FAR ENOUGH SOUTH TO RESULT IN ANOTHER ROUND OF MVFR CIGS. AT THIS
POINT WILL CONTINUE THE MVFR MENTION OVERNIGHT BUT WILL MONITOR
TRENDS IN OBS THROUGH THE EVENING.
//DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CEILING BELOW 5000 FEET THROUGH INTO THIS EVENING. LOW
TONIGHT.
&&
.PREV DISCUSSION...ISSUED 1026 AM EST MON JAN 12 2015
UPDATE...
SNOW IS WINDING DOWN ACROSS FAR SE LOWER MI AS THE FGEN BAND PULLS
FURTHER EAST. DRY AIR IS NOW WORKING INTO THE AREA AND WILL
CONTINUE TO DO SO THROUGH THE DAY. DEWPOINTS IN NORTHERN LOWER
HAVE FALLEN TO AROUND 10F AND FURTHER WEST IN WI ARE -5F OR LOWER.
THIS IS THE AIRMASS WITHIN THE STRONG +1040MB HIGH PRESSURE
SYSTEM THAT WILL ADVECT OVER THE AREA NOW THROUGH THE OVERNIGHT.
MINOR ADJUSTMENTS TO POPS TO CLEAR THE LAST OF THE SNOW OUT.
ATTENTION THEN TURNS TO JUST HOW LOW TEMPS GET TONIGHT AND HOW FAR
THE LAKE EFFECT CLOUDS OFF LAKE HURON CAN MAKE IT INLAND.
PREV DISCUSSION...ISSUED 346 AM EST MON JAN 12 2015
SHORT TERM...TODAY AND TONIGHT
AFTER A LULL IN THE SNOW SHORTLY AFTER MIDNIGHT...TRENDS IN THE
RADAR AND SFC OBS ARE SHOWING A REINTENSIFICATION OF SNOWFALL ACROSS
NRN INDIANA INTO SE MI. THIS IS THE RESULT OF A RENEWED
STRENGTHENING OF SOME MID TROPOSPHERIC FRONTAL FORCING /IN THE 800-
700MB LAYER/ AND WILL TARGET LOCALS SOUTH OF A SANDUSKY TO OWOSSO
LINE EARLY THIS MORNING. THE FRONTAL CIRCULATION WILL ADVANCE TO THE
EAST DURING THE COURSE OF THE MORNING AS THE UPPER JET SUPPORT
SLIDES EAST OF THE STATE. THE CURRENT NAM AND SEVERAL HI RES
SOLUTIONS SUGGEST THE FORCING WILL WEAKEN AS IT HEADS EAST OF METRO
DETROIT BETWEEN 12Z AND 15Z THIS MORNING. SNOWFALL INTENSITY WILL
FLUCTUATE DURING THE MORNING AS THE STRENGTH OF THE MID LEVEL LIFT
VARIES. IN LIGHT OF THE FORCING AND PROJECTED NEAR TERM QPF
AMOUNTS...ADDITIONAL SNOWFALL ACCUMS BETWEEN A HALF INCH AND INCH
THROUGH DAYBREAK STILL SEEM REASONABLE. BASED ON REPORTS PRIOR TO
MIDNIGHT...THIS SHOULD LEAD TO TOTAL SNOWFALL SOUTH OF A BAD AXE TO
SAGINAW LINE OF 1 TO 3 INCHES. THE HIGHER TOTALS WILL OCCUR ACROSS
THE NRN DETROIT SUBURBS WHERE FORCING WAS A LITTLE MORE PERSISTENT
OVERNIGHT. THERE IS A SECONDARY REGION OF RADAR RETURNS PUSHING
SOUTH ACROSS NRN LOWER MI...OCCURRING ALONG THE 600-500MB PORTION OF
THE FRONT. THE FORCING IS EXPECTED TO WEAKEN AS IT ENTERS THE
SAGINAW VALLEY AND THUMB EARLY THIS MORNING. UPSTREAM RETURNS
HOWEVER SUPPORT AT LEAST CHANCE POPS ACROSS THE NRN THIRD OF THE
FORECAST AREA THIS MORNING. UNTREATED ROADS WILL BE VERY SLICK THIS
MORNING AS THIS SNOW HAS A HIGH WATER CONTENT. WITH TEMPS IN THE
UPPER 20S...ROAD TREATMENTS SHOULD PROVE HIGHLY EFFECTIVE.
WHILE THE COLD FRONT WILL MOVE EAST OF THE AREA EARLY THIS
MORNING...THE PUSH OF ARCTIC AIR WILL NOT ARRIVE INTO SE MI UNTIL
THIS AFTERNOON UNDER STRENGTHENING NORTHERLY WINDS. THIS WILL
SUPPORT MORNING HIGHS /MID 20S TO LOW 30S/...WITH FALLING TEMPS
DURING THE AFTERNOON. WHILE THE MID LEVEL TROUGH AXIS NOW
APPROACHING LAKE SUPERIOR WILL NOT TRAVERSE SE MI UNTIL THIS
EVENING...LARGE SCALE SUBSIDENCE WITHIN THE DESCENDING BRANCH OF THE
MID TROP FRONT WILL LEAD TO SUBSTANTIAL MID LEVEL DRYING THIS
AFTERNOON. THIS WILL KEEP CONDITIONS PRECIP FREE OUTSIDE OF SOME
LAKE EFFECT SNOW SHOWERS OVER THE THUMB REGION UNDER NORTHERLY FLOW.
THE NAM AND 4KM WRF NMM SHOW A DOMINATE LAKE BAND DEVELOPING OVER
THE SRN LAKE HURON BASIN THIS EVENING. THE COLD AIR ADVECTION WILL
BE SHALLOW...SUPPORTING EQUILIBRIUM LEVELS ONLY TO 5K FT.
HOWEVER...STEEP LOW LEVEL LAPSE RATES WITH TEMPS OF -16 TO -18C NEAR
THE NEAR THE TOP OF THE MIXED LAYER COULD LEAD TO SOME GOOD SNOWFALL
RATES. A GRADUAL BACKING OF THE FLOW TO THE NNE AIDED BY A LAND
BREEZE PUSH OFF ONTARIO MAY BRING THIS BAND INTO THE ERN THUMB AND
PORT HURON. WILL KEEP ANY ACCUMS MINOR ATTM /AN INCH OR TWO IN PORT
HURON/. LAKE STRATO CU SHOULD PUSH INTO PORTIONS OF FLINT AND METRO
DETROIT TONIGHT. NAM AND RUC SOUNDINGS SHOW GOOD SUPERSATURATION
WITH RESPECT TO ICE AROUND -16C. THIS MAY BE SUPPORTIVE OF SOME
FLURRIES/LIGHT SNOW SHOWERS OUT OF THE STRATO CU. REGIONS THAT SEE
THE CLOUDS TONIGHT WILL HAVE MIN TEMPS HOLD IN THE SINGLE
DIGITS...WHILE LOCALS ACROSS THE WRN HALF OF THE FORECAST AREA
SHOULD DECOUPLE ENOUGH TO SUPPORT SUB ZERO MINS.
LONG TERM...TUESDAY THROUGH SUNDAY
STRONG SURFACE HIGH PRESSURE WILL REMAIN SPRAWLED OVER THE GREAT
LAKES TUESDAY AND TUESDAY NIGHT. THIS WILL BRING QUIET WEATHER TO
THE AREA AS LAKE EFFECT POTENTIAL OFF LAKE HURON LOOKS TO DECREASE
BY SUNRISE. THIS WILL OCCUR AS INVERSION HEIGHTS/CONVECTIVE DEPTHS
DECREASE AS THE HIGH SETTLES IN...AND AS WINDS TURN MORE EASTERLY
DECREASING THE FETCH. THE DAY SHOULD START OUT WITH PLENTY OF
STRATUS LOCKED UNDER THE INVERSION STRETCHING FROM THE THUMB DOWN TO
THE DETROIT AREA. THIS LAYER SHOULD MIX OUT LATER IN THE AFTERNOON
HOWEVER PER LATEST FORECAST SOUNDINGS FROM NAM/GFS. UPSTREAM
OBSERVATIONS DEPICT A VERY DRY AND COLD AIRMASS UNDER THE RIDGE OVER
CANADA AND THE NORTHERN PLAINS (CURRENT DEWPOINTS -20 TO -30
F...WITH MAX TEMPS YESTERDAY BETWEEN -5 AND 15 F). THE AIRMASS
SHOULD MODIFY SOME AS IT CROSSES THE STILL UNFROZEN GREAT
LAKES...AND EXPECTING MAX TEMPS TUESDAY TO REACH THE MID TEENS. IT
IS POSSIBLE IF WE GET ENOUGH SUNSHINE WE COULD OVERACHIEVE...BUT
WILL LEAN THE FORECAST ON THE PESSIMISTIC SIDE GIVEN HIGH POTENTIAL
FOR LAKE STRATUS DURING THE EARLY PART OF THE DAY. MINS OVERNIGHT
WILL BECOME VERY COLD AS EXCELLENT RADIATIONAL COOLING CONDITIONS SET
UP UNDER THE RIDGE CENTER...WITH CLEAR SKIES...LIGHT/CALM
WINDS...FRESH SNOW...AND A VERY DRY AIRMASS. CONTINUED TREND FROM
INHERITED FORECAST WITH MIN TEMPS BELOW MOS GUIDANCE...FROM NEAR
ZERO TO ABOUT 7 BELOW.
WEAK UPPER SHORTWAVE WILL CLIP ACROSS MICHIGAN WEDNESDAY AS IT
PIVOTS AROUND THE UPPER VORTEX CENTERED NORTH OF HUDSON BAY. SURFACE
REFLECTION LOOKS VERY WEAK...AND WILL ONLY MAKE A SMALL RIPPLE IN
THE SURFACE HIGH STILL EXTENDING FROM THE CENTRAL PLAINS UP THROUGH
THE OHIO VALLEY. FRONTAL BOUNDARY WILL WASH OUT AS IT CROSSES
MICHIGAN WITH THIS SYSTEM...BUT FORCING LOOKS TOO WEAK TO OVERCOME
VERY DRY AIRMASS THAT WILL PRECEDE IT. THE RIDGE AXIS WILL GET
PUSHED TO OUR SOUTH AND EAST WEDNESDAY NIGHT AND THURSDAY AS ANOTHER
CLIPPER SYSTEM IS GUIDED ACROSS ONTARIO AROUND THE VORTEX NORTH OF
HUDSON BAY. PRECIPITATION ASSOCIATED WITH THIS SYSTEM LOOKS TO
REMAIN WELL TO OUR NORTH.
BY FRIDAY MEDIUM-RANGE MODELS ARE IN GOOD AGREEMENT WITH ANOTHER
RIDGE OF SURFACE HIGH PRESSURE ENCOMPASSING THE GREAT LAKES...BUT
DIFFER WITH THE AMPLIFICATION OF THE UPSTREAM PATTERN OVER THE
WESTERN U.S. AND CANADA. THIS RESULTS IN SOME UNCERTAINTY WITH THE
FORECAST AS WE HEAD INTO THE WEEKEND AND EARLY NEXT WEEK AS MODEL
SOLUTIONS DIFFER GREATLY IN TIMING THE ARRIVAL OF GULF OF ALASKA
ENERGY INTO THE GREAT LAKES. 00Z EURO/GEM CURRENTLY HAVE THE
STRONGEST CONSENSUS AT 144 HOURS...BUT RUN TO RUN CONSISTENCY IN THE
EURO HAS NOT BEEN STRONG. BOTH THESE SOLUTIONS TRACK SURFACE LOW
PRESSURE INTO THE GREAT LAKES ON SATURDAY...BUT WITH ENOUGH OF A
NORTHERLY TRACK TO KEEP MOST PRECIPITATION OUT OF SOUTHEAST MICHIGAN
SO THE FORECAST REMAINS DRY. ADDITIONAL ENERGY LOOKS TO
FOLLOW...POSSIBLY SETTING US UP IN A MORE ACTIVE PATTERN FOR EARLY
NEXT WEEK. TEMPERATURES DO LOOK TO MODERATE FRIDAY AND THROUGH THE
WEEKEND AS ARCTIC CLIPPERS STOP DIVING THROUGH THE AREA. EXPECTING
MAX TEMPS TO WARM BACK CLOSER TO FREEZING.
MARINE...
GUSTY WINDS WILL DEVELOP OVER LAKE HURON TODAY IN THE WAKE OF AN
EARLY MORNING COLD FRONT. NORTHWESTERLY WIND GUSTS TO 30 KNOTS WILL
BE POSSIBLE OVER ALL BUT INNER SAGINAW BAY. WAVE HEIGHTS WILL ALSO
INCREASE TO AS HIGH AS 7 FEET OVER ICE FREE AREAS THIS AFTERNOON AND
EARLY TONIGHT AS THE FETCH INCREASES. THE COMBINATION OF GUSTY
WINDS...LARGE WAVES...AND COLD TEMPERATURES WILL ALSO CREATE AREAS
OF HEAVY FREEZING SPRAY OVER CENTRAL AND SOUTHERN LAKE
HURON...ESPECIALLY OVER THE OPEN WATERS AND OFF THE TIP OF THE
THUMB. STRONG HIGH PRESSURE BUILDING INTO THE GREAT LAKES TONIGHT
WILL ALLOW FOR A GRADUAL DECREASE IN WINDS AND WAVES TONIGHT. THE
HIGH WILL THEN BRING VERY LIGHT WINDS AS IT SETTLES OVERHEAD ON
TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST TUESDAY FOR LHZ363-421-
441-462>464.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR LHZ421-441>443.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DRK
UPDATE.......DRK
SHORT TERM...SC
LONG TERM....HLO
MARINE.......HLO
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1245 PM EST MON JAN 12 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST MON JAN 12 2015
WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROF EXTENDING FROM SRN HUDSON
BAY TO MN...AND LATEST RUC ANALYSIS SHOWS 850MB THERMAL TROF WITH
TEMPS OF -20 TO -28C APPROACHING NW LAKE SUPERIOR ATTM. AT THE
SFC...ASSOCIATED COLD FRONT EXTENDS FROM NEAR KIWD E TO NEAR
WHITEFISH PT. DESPITE APPROACHING SHORTWAVE TROF AND FAIRLY DECENT
DEEP LAYER FORCING PER QVECTORS...LES OVER LAKE SUPERIOR HAS NOT
SHOWN MUCH CHANGE IN INTENSITY OVERNIGHT. LACK OF MUCH REFLECTIVITY
AOA 28DBZ SUGGESTS SNOW IS MOSTLY LIGHT TO OCCASIONALLY MDT.
WITH DEEP LAYER FORCING THRU ABOUT MID MORNING AND INCREASING
OVERWATER INSTABILITY...EXPECT SOME UPTICK IN LES OVER THE NEXT
SEVERAL HRS. THIS INCREASE SHOULD BE MORE APPARENT OVER FAR WRN
UPPER MI (GOGEBIC/ONTONAGON COUNTIES) AS SHARPER LOW-LEVEL
CONVERGENCE DEVELOPS THERE FOR A SHORT TIME...AND THEN ALSO OVER
NCNTRL UPPER MI (MARQUETTE/ALGER COUNTIES) WHERE A MORE CONVERGENT
NRLY FLOW DEVELOPS. LONGER FETCH AND DEEPER DGZ WILL ULTIMATELY LEAD
TO GREATEST SNOW ACCUMULATIONS IN NCNTRL UPPER MI...ROUGHLY IN THE
AREA BTWN NEGAUNEE AND MUNISING WHERE SNOW ACCUMULATIONS OF 2-4
INCHES WILL BE PAINTED TODAY. 2-3 INCHES ARE POSSIBLE FROM KIWD TO
THE PORCUPINE MTNS. OTHERWISE...SNOW ACCUMULATIONS ACROSS THE REST
OF THE FCST AREA NEAR LAKE SUPERIOR SHOULD BE ON THE ORDER OF AN
INCH OR TWO TODAY. THIS AFTN...STRONG DEEP LAYER QVECTOR DIVERGENCE
IN THE WAKE OF SHORTWAVE AND CORRESPONDING LOWERING OF INVERSION
COMBINED WITH INCREASINGLY ANTICYCLONIC 925MB FLOW AHEAD OF STRONG
ARCTIC HIGH PRES BUILDING INTO THE PLAINS/UPPER MISSISSIPPI VALLEY
WILL LEAD TO DIMINISHING LES COVERAGE/INTENSITY. BRIEF SHOT OF
ARCTIC AIR WILL LEAD TO A COLDER DAY TODAY. EXPECT HIGHS IN THE 5 TO
15 RANGE...COLDEST W.
CENTER OF ARCTIC HIGH PRES WILL MOVE INTO THE WRN GREAT LAKES
TONIGHT. MODERATING 850MB TEMPS AND BACKING WINDS WILL BRING AN END
TO ANY LINGERING LIGHT LES OVER NW UPPER MI EARLY THIS EVENING. LAST
OF THE LES OVER NCNTRL UPPER MI SHOULD SHIFT OFFSHORE BY 06Z.
CLEARING SKIES/DRY COLUMN AND CALM WIND FOR MUCH OF THE AREA FOR
MOST...IF NOT ALL...OF THE NIGHT WILL LEAD TO EXCELLENT RADIATIONAL
COOLING. FAVORED THE LOWEST GUIDANCE WHICH IS THE GLOBAL GEM BIAS
CORRECTED. AS IT HAS FOR THE LAST FEW DAYS...IT SHOWS MINS AS LOW AS
THE LOW TO MID -20S IN THE INTERIOR W HALF TONIGHT. THIS MATCHES UP
FAIRLY WELL WITH CURRENT UPSTREAM TEMPS ACROSS SRN SASKATCHEWAN/SRN
MANITOBA. WOULD NOT BE SURPRISED TO SEE THE COLDEST OF THE
TRADITIONAL COLD SPOTS BOTTOM OUT AROUND -25F TONIGHT. THE ONLY AREA
THAT MIGHT NOT SEE TEMPS FALL BLO ZERO TONIGHT IS OVER THE TIP OF
THE KEWEENAW.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 456 AM EST MON JAN 12 2015
GENERALLY GOOD AGREEMENT FM THE MODELS IN LARGER SCALE PATTERN
EVOLUTION INTO NEXT WEEKEND AS DEEP TROUGH OVER EASTERN CANADA AND
GREAT LAKES SLOWLY UNRAVELS LEADING TO ZONAL FLOW AND TEMPS NUDGING
TOWARD NORMAL OR EVEN SLIGHTLY ABOVE. THAT IS THE LONG AND SHORT OF
IT...BUT DETAILS ARE MUDDLED AND MAINLY HAVE TO DO WITH SOUTHERN
EXTENT OF SERIES OF SHORTWAVES/SFC TROUGHS LATE THIS WEEK AS THE
PATTERN TRIES TO BECOME MORE ZONAL. STILL LOOKS LIKE A PRETTY GOOD
BET THAT TEMPS WILL EXCEED 30 DEGREES IN SOME PART OF THE CWA
THURSDAY INTO SATURDAY. NEXT SATURDAY IS A GOOD CANIDATE FOR THAT
WARM DAY AS IT APPEARS STRONGER SFC LOW TRACKS NORTH OF UPR
MICHIGAN...PLACING THE AREA IN A MORE DEVELOPED WARM SECTOR. WARM IS
RELATIVE AT THIS POINT. MIXING TO 925-900MB SUPPORTS HIGHS WELL INTO
THE 30S. THAT WOULD BE A PROVERBIAL HEAT WAVE COMPARED TO THE CHILL
THAT HAS BEEN OVER THE UPPER GREAT LAKES SINCE JUST BEFORE THE NEW
YEAR BEGAN.
FORECASTED PATTERN HOLDS MINIMAL CHANCE FOR MUCH IN WAY OF HIGH
IMPACT WEATHER. AFTER A DAY WITH A COLD START BUT PLENTY OF SUNSHINE
ON TUESDAY...COULD BE SOME WIDESPREAD LGT SNOW OVER THE AREA TUESDAY
NIGHT WEST/CENTRAL INTO WEDNESDAY MORNING EAST DUE TO SHORTWAVE
TROUGH AND ASSOCIATED MID- LEVEL WARM AIR ADVECTION. NAM AND GFS SHOW
MOST QPF AS THEY ARE MOST SATURATED BLO H85...BUT STILL ONLY LOOKING
AT LESS THAN 2 INCHES OF SNOW DUE TO LIMITED MOISTURE AND NOT EVEN 6
HOURS OF STEADY SNOW. EXCEPTION MAY BE OVER THE NORTHERN KEWEENAW AS
H9 TEMPS ARE ALREADY -14C WITH AN ONSHORE WSW FLOW AS BETTER FORCING
CROSSES THE AREA. MIGHT SEE LAKE ENHANCEMENT AT LEAST BRIEFLY BEFORE
WINDS VEER NORTHWEST ON WEDNESDAY MORNING. STEADILY VEERING WINDS
SHOULD KEEP CAP ON AMOUNTS VIA LAKE ENHANCEMENT. TEMPS TUESDAY NIGHT
INTO WEDNESDAY MORNING TRICKY WITH NON-DIURNAL CURVE EXPECTED DUE TO
INCREASING CLOUDS LATER AT NIGHT AS THE SYSTEM MOVES THROUGH. ONLY A
WEAK COLD FRONT PASSAGE ON WEDNESDAY...MAINLY AFFECTING THE KEWEENAW.
SOUNDINGS EVEN THERE THOUGH LOOK LESS FAVORABLE AS DAY WEARS ON WITH
DRYING ABOVE H875 AND INVERSIONS LESS THAN 5KFT. KEPT CHANCES GOING
SINCE DELTA T/S WILL BE ABOVE 15C...BUT NEGATIVE FACTORS SHOULD
HAMPER ADDITIONAL LAKE EFFECT SNOW SHOWERS. TEENS TO LOW 20S FOR
HIGHS ON WEDNESDAY.
NW FLOW ALOFT RESULTS IN ANOTHER SHORTWAVE AND SFC TROUGH CROSSING
LK SUPERIOR AND MAINLY NORTHERN UPR MICHIGAN ON WEDNESDAY NIGHT.
STRONGER FORCING AND GREATEST CHANCES FOR SNOW WILL BE OVER NORTHERN
ONTARIO CLOSER TO DEEPENING SFC LOW TRACKING TOWARD JAMES BAY. SETUP
OVER CWA SIMILAR TO TUE NIGHT WITH BEST MOISTENING/LIFT OCCURRING
ALOFT ROUGHLY H85-H6. SLIGHT CHANCES ALL AREAS...BUT ONLY CARRIED
CHANCE POPS ON KEWEENAW DUE TO HIGHER 1000-850MB RH WITH ONSHORE
WSW-W WINDS PROVIDING POSSIBLE ADDITIONAL MOISTURE. WARMING TREND
BEGINS TO BE NOTED WITH MINS WED NIGHT MOSTLY 10 ABOVE OR HIGHER
OVER ALL CWA. LAST WEEK IT WAS A STRUGGLE TO REACH 10 ABOVE FOR A
HIGH TEMPERATURE. SFC LOW CONTINUES EASTWARD AND A SW-W WIND SHOULD
STAY IN PLACE OVER UPR MICHIGAN. SMALL CHANCES ESPECIALLY NORTH AND
EAST BUT DRYING TREND SHOULD WIN OUT BY AFTN. SOUNDINGS SHOW MIXING
TO H925...WHICH ALLOWS MOST AREAS TO REACH WELL INTO THE 20S AND
SOME SPOTS TO POSSIBLY CRACK 30 DEGREES.
MODELS HAVE STEADILY TRENDED TO LESS AND LESS COLD AIR INTRUSION FOR
COLD FRONT PASSAGE ON THU NIGHT INTO FRIDAY. H925/H85 TEMPS AT 12Z
FRIDAY STILL COOLER OFF GFS AT -10C/-8C BUT ECMWF IS REALLY TRENDING
WARMER WITH VALUES ONLY -4C/-6C. GEM-NH LOOKS LIKE THE WARMER ECMWF.
ALTHOUGH LES LOOKS UNLIKELY...GFS/ECMWF/GEM-NH INDICATE SHORTWAVE
DROPPING THROUGH IN WNW FLOW ALOFT ALONG WITH SOME FORCING AND
MOISTURE ALONG COLD FRONT THAT ATTEMPTS TO DROP SOUTHWARD TOWARD
UPR MICHIGAN. LOW CHANCE POPS...NOT SURE ON THE TIMING AS MODELS
DIFFER...SEEM REASONABLE OVER THE NORTH CWA DUE TO THESE SIGNALS.
AS ALLUDED TO BEFORE...MODEL DIFFERENCES CONTINUE INTO NEXT WEEKEND
WITH REGARD TO HOW FAR SOUTH ANOTHER LOW PRESSURE TROUGH CROSSES THE
AREA. EARLIER RUNS OF ECMWF WERE MORE AGGRESSIVE IN A FARTHER SOUTH
TRACK TO LOW BUT LATEST RUNS ARE MORE LIKE THE GFS AND GEM-NH WITH
SFC LOW AND MOST PRECIP STAYING NORTH OF UPR MICHIGAN OR AT LEAST
DELAYED INTO UPR GREAT LAKES. DID NOT STRAY TOO MUCH FM CONSENSUS
GUIDANCE FOR NEXT WEEKEND...BUT WITH THE TREND FM ECMWF...HEADED
TOWARD WARMER TEMPS INTO THE 30S MOST AREAS ON SATURDAY WITH
EXPECTATION THAT CWA WILL BE WITHIN WARM SECTOR MOST OF THE DAY.
INTERESTING THAT MEX GUIDANCE /EXTENDED GFS MOS NUMBERS/ CHECKS
IN AT 33-40F FOR NEXT SATURDAY OVER THE CWA. CLIMO IN THE LOW-MID
20S...SO THAT IS A DECENT DEPARTURE FM AVERAGE AT A POINT IN MOS
WHERE THERE IS USUALLY A BIAS BACK TOWARD CLIMO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1245 PM EST MON JAN 12 2015
SURFACE RIDGING AND DRIER AIR PUSHING INTO THE U.P. WILL ALLOW LAKE
EFFECT SNOW SHOWERS TO DIMINISH. MVFR CIGS AND VSBYS WILL CONTINUE
THROUGH THE AFTERNOON BEFORE SKIES CLEAR THIS EVENING. EXPECT VFR
CONDITIONS THEREAFTER THROUGH TOMORROW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 456 AM EST MON JAN 12 2015
TYPICALLY STRONG WINDS FOR WINTER EXPECTED MUCH OF THIS LAST WEEK OF
THE SHIPPING SEASON. NORTH WINDS TO 30 KTS THIS MORNING DIMINISH TO
LESS THAN 20 KTS BRIEFLY TONIGHT. WITH A SURGE OF ARCTIC AIR AND
BUILDING WAVES...EXPECT A PERIOD OF HEAVY FREEZING SPRAY OVER MUCH
OF THE LAKE IN LINE WITH GOING WARNINGS. WINDS RAMP UP TO 30 KTS FM
THE WEST OR SOUTHWEST TUESDAY AND TUESDAY NIGHT AHEAD OF AN COLD
FRONT. STRONGEST WINDS OVER WESTERN LK SUPERIOR...AND CANNOT COUNT
OUT A PERIOD OF GALES BTWN ISLE ROYALE AND THE KEWEENAW LATE
TUESDAY. ADDITIONAL HEAVY FREEZING SPRAY IS POSSIBLE OVER WESTERN LK
SUPERIOR DURING THIS TIME. COLD FRONT SLIDES OVER THE LAKE ON
WEDNESDAY AND WINDS SETTLE DOWN TO LESS THAN 25 KTS BY WEDNESDAY
AFTN. LULL IS BRIEF AS WEST WINDS INCREASE TO 25-30 KTS BY THURSDAY
MORNING OUT AHEAD OF ANOTHER COLD FRONT THAT DROPS OVER LK SUPERIOR
ON FRIDAY. THOUGH WINDS DIMINISH TO LESS THAN 25 KTS LATER ON
FRIDAY...WINDS INCREASE AGAIN BY NEXT SATURDAY FM THE SOUTH OUT OF
AN APPROACHING LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ248>251-265>267.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR LSZ162.
HEAVY FREEZING SPRAY WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
LSZ243-244-264.
HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THIS
AFTERNOON FOR LSZ241-242-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1105 AM CST Mon Jan 12 2015
.UPDATE:
Issued at 742 AM CST Mon Jan 12 2015
Will be allowing all headlines to expire at 9 AM. Only some
lingering patchy drizzle or flurries expected across eastern
Ozarks to southwest Illinois for the next few hours. Clearing line
rapidly moving southeast into mid Missouri at this time and cloud
trends have been updated to account for this faster clearing.
CVKING
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 319 AM CST Mon Jan 12 2015
Difficult decision to make this morning regarding the advisory.
Short-range guidance is pretty persistent in redeveloping a band of
light precipitation between I-70 and I-44 in Missouri extending
through the STL Metro area northeast into Illinois between 11Z and
13Z this morning. RAP and NAM are showing some pretty stout
frontogenesis along this corridor during this time period and
various iterations of the WRF model and the HRRR show simulated
light reflectivity in this area. Have therefore increased PoPs to
likely in this area through 14-15Z this morning. Wind has already
swung around to the north along and north of the I-70 corridor and
cooler air is filtering south. The freezing line stretches from
just north of Columbia to Pittsfield at this time, but the north
wind should push it south over the next few hours...and it looks
likely to reach the area in question between 12-13Z Forecast
soundings show little if any ice crystals in the column, but
saturated conditions with temperatures between 0 and -4C there
should be plenty of supercooled water. Ground temperatures are
right at freezing and have had numerous reports of patchy ice on
untreated surfaces last evening and overnight. I`m afraid that
between the cold ground temps and the cold air filtering into the
area the morning rush hour will be slippery. Additionally, rain
overnight may have washed chemicals off the roads which will only
add to the potential for a light glaze. Additionally, MODOT road
condition map is reporting partial coverage across parts of our
southern CWFA, so there`s obviously a little bit of glazing
occurring down there as well. With all this in mind, I cannot in
good conscience let the current advisory expire at 600 AM along and
south of the I-70 corridor across eastern Missouri and Illinois.
Further north/west, the precipitation should be ending pretty
quickly over the next 2-3 hours as drier air filters in behind the
cold front. Will allow the advisory to expire on time from Columbia
to Pittsfield.
Carney
.LONG TERM: (Tonight through Sunday)
Issued at 350 AM CST Mon Jan 12 2015
Weather should be (thankfully) quieter after we get rid of today`s
precip. Another Arctic high will build across the Midwest tonight
and Tuesday. The upper level trof preceding the high doesn`t
amplify the flow enough over the eastern CONUS to allow the ridge
axis to dig much further south than central Illinois or northern
Missouri before the high starts to weaken. Not to say that it won`t
be cold...lows Tuesday morning will range from near zero in
northeast MO to the low and mid teens across the eastern Ozarks.
Northerly flow will continue on Tuesday which will keep temperatures
down in the teens and 20s. A shortwave will ripple overhead
Wednesday which will turn the winds aloft to the west-southwest.
NAM kicks out a little light QPF with the wave, but the GFS is dry.
Low levels should stay very dry, so any precip that does form should
be very light. Should be cold enough for any precip that does form
to be snow, so have added some scattered flurries to the forecast.
Forecast for Thursday through Sunday remains dry at this time, with
an impressive warming trend Friday and Saturday. The lingering high
pressure system will moderate with light west wind on Thursday, and
the GFS and ECMWF have been very consistent in developing warm
southerly flow Friday and continuing into Saturday. GFS is warmer
than than the ECMWF, but have trended a bit toward the warmer
solution and increased temperatures a few degrees over ensemble
guidance. Should be some welcome relief with temperatures well into
the 40s across the area and even around 50 in across parts of
central and eastern Missouri.
Carney
&&
.AVIATION: (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1057 AM CST Mon Jan 12 2015
Specifics for KCOU, KUIN: VFR through the period with northerly
winds subsiding overnight and becoming northeasterly towards the
end of the TAF period.
Specifics for KSTL, KSUS, KCPS: An MVFR cloud deck was located
overhead at TAF issuance, but the back edge was knocking on the
terminals` doorsteps. Expect clearing within 1-2 hours. Gusty
northerly winds will subside overnight and veer around the south
side of a high pressure center over the Great Lakes, becoming
northeasterly towards the end of the TAF period.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
747 AM CST Mon Jan 12 2015
.UPDATE:
Issued at 742 AM CST Mon Jan 12 2015
Will be allowing all headlines to expire at 9 AM. Only some
lingering patchy drizzle or flurries expected across eastern
Ozarks to southwest Illinois for the next few hours. Clearing line
rapidly moving southeast into mid Missouri at this time and cloud
trends have been updated to account for this faster clearing.
CVKING
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 319 AM CST Mon Jan 12 2015
Difficult decision to make this morning regarding the advisory.
Short-range guidance is pretty persistent in redeveloping a band of
light precipitation between I-70 and I-44 in Missouri extending
through the STL Metro area northeast into Illinois between 11Z and
13Z this morning. RAP and NAM are showing some pretty stout
frontogenesis along this corridor during this time period and
various iterations of the WRF model and the HRRR show simulated
light reflectivity in this area. Have therefore increased PoPs to
likely in this area through 14-15Z this morning. Wind has already
swung around to the north along and north of the I-70 corridor and
cooler air is filtering south. The freezing line stretches from
just north of Columbia to Pittsfield at this time, but the north
wind should push it south over the next few hours...and it looks
likely to reach the area in question between 12-13Z Forecast
soundings show little if any ice crystals in the column, but
saturated conditions with temperatures between 0 and -4C there
should be plenty of supercooled water. Ground temperatures are
right at freezing and have had numerous reports of patchy ice on
untreated surfaces last evening and overnight. I`m afraid that
between the cold ground temps and the cold air filtering into the
area the morning rush hour will be slippery. Additionally, rain
overnight may have washed chemicals off the roads which will only
add to the potential for a light glaze. Additionally, MODOT road
condition map is reporting partial coverage across parts of our
southern CWFA, so there`s obviously a little bit of glazing
occurring down there as well. With all this in mind, I cannot in
good conscience let the current advisory expire at 600 AM along and
south of the I-70 corridor across eastern Missouri and Illinois.
Further north/west, the precipitation should be ending pretty
quickly over the next 2-3 hours as drier air filters in behind the
cold front. Will allow the advisory to expire on time from Columbia
to Pittsfield.
Carney
.LONG TERM: (Tonight through Sunday)
Issued at 350 AM CST Mon Jan 12 2015
Weather should be (thankfully) quieter after we get rid of today`s
precip. Another Arctic high will build across the Midwest tonight
and Tuesday. The upper level trof preceding the high doesn`t
amplify the flow enough over the eastern CONUS to allow the ridge
axis to dig much further south than central Illinois or northern
Missouri before the high starts to weaken. Not to say that it won`t
be cold...lows Tuesday morning will range from near zero in
northeast MO to the low and mid teens across the eastern Ozarks.
Northerly flow will continue on Tuesday which will keep temperatures
down in the teens and 20s. A shortwave will ripple overhead
Wednesday which will turn the winds aloft to the west-southwest.
NAM kicks out a little light QPF with the wave, but the GFS is dry.
Low levels should stay very dry, so any precip that does form should
be very light. Should be cold enough for any precip that does form
to be snow, so have added some scattered flurries to the forecast.
Forecast for Thursday through Sunday remains dry at this time, with
an impressive warming trend Friday and Saturday. The lingering high
pressure system will moderate with light west wind on Thursday, and
the GFS and ECMWF have been very consistent in developing warm
southerly flow Friday and continuing into Saturday. GFS is warmer
than than the ECMWF, but have trended a bit toward the warmer
solution and increased temperatures a few degrees over ensemble
guidance. Should be some welcome relief with temperatures well into
the 40s across the area and even around 50 in across parts of
central and eastern Missouri.
Carney
&&
.AVIATION: (For the 12z TAFs through 12z Tuesday Morning)
Issued at 501 AM CST Mon Jan 12 2015
Temperatures are starting to fall below zero as colder air rushes
into the area behind the departing storm system. Some lingering
drizzle and light snow will cause some concern for a few hours in
St. Louis. Trend should be for lifting ceiling and scattering by
evening as high pressure moves into the area. North wind will
increase this morning and become gusty to 25kts.
Specifics for KSTL:
Some light drizzle and flurries are expected for the next few
hours. Temperatures should drop below freezing in the next two
hours which could mean refreezing of moisture on runways. The rest
of the day should feature improving conditions in ceiling and an
eventual scattering/clearing this evening. North wind will
increase and gust to 25kt today as cold high pressure builds into
the region.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Callaway
MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-Iron MO-
Jefferson MO-Lincoln MO-Madison MO-Montgomery MO-Osage MO-
Reynolds MO-St. Charles MO-St. Francois MO-St. Louis City
MO-St. Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
IL...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Bond IL-
Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Randolph IL-St. Clair IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
505 AM CST Mon Jan 12 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 319 AM CST Mon Jan 12 2015
Difficult decision to make this morning regarding the advisory.
Short-range guidance is pretty persistent in redeveloping a band of
light precipitation between I-70 and I-44 in Missouri extending
through the STL Metro area northeast into Illinois between 11Z and
13Z this morning. RAP and NAM are showing some pretty stout
frontogenesis along this corridor during this time period and
various iterations of the WRF model and the HRRR show simulated
light reflectivity in this area. Have therefore increased PoPs to
likely in this area through 14-15Z this morning. Wind has already
swung around to the north along and north of the I-70 corridor and
cooler air is filtering south. The freezing line stretches from
just north of Columbia to Pittsfield at this time, but the north
wind should push it south over the next few hours...and it looks
likely to reach the area in question between 12-13Z Forecast
soundings show little if any ice crystals in the column, but
saturated conditions with temperatures between 0 and -4C there
should be plenty of supercooled water. Ground temperatures are
right at freezing and have had numerous reports of patchy ice on
untreated surfaces last evening and overnight. I`m afraid that
between the cold ground temps and the cold air filtering into the
area the morning rush hour will be slippery. Additionally, rain
overnight may have washed chemicals off the roads which will only
add to the potential for a light glaze. Additionally, MODOT road
condition map is reporting partial coverage across parts of our
southern CWFA, so there`s obviously a little bit of glazing
occurring down there as well. With all this in mind, I cannot in
good conscience let the current advisory expire at 600 AM along and
south of the I-70 corridor across eastern Missouri and Illinois.
Further north/west, the precipitation should be ending pretty
quickly over the next 2-3 hours as drier air filters in behind the
cold front. Will allow the advisory to expire on time from Columbia
to Pittsfield.
Carney
.LONG TERM: (Tonight through Sunday)
Issued at 350 AM CST Mon Jan 12 2015
Weather should be (thankfully) quieter after we get rid of today`s
precip. Another Arctic high will build across the Midwest tonight
and Tuesday. The upper level trof preceding the high doesn`t
amplify the flow enough over the eastern CONUS to allow the ridge
axis to dig much further south than central Illinois or northern
Missouri before the high starts to weaken. Not to say that it won`t
be cold...lows Tuesday morning will range from near zero in
northeast MO to the low and mid teens across the eastern Ozarks.
Northerly flow will continue on Tuesday which will keep temperatures
down in the teens and 20s. A shortwave will ripple overhead
Wednesday which will turn the winds aloft to the west-southwest.
NAM kicks out a little light QPF with the wave, but the GFS is dry.
Low levels should stay very dry, so any precip that does form should
be very light. Should be cold enough for any precip that does form
to be snow, so have added some scattered flurries to the forecast.
Forecast for Thursday through Sunday remains dry at this time, with
an impressive warming trend Friday and Saturday. The lingering high
pressure system will moderate with light west wind on Thursday, and
the GFS and ECMWF have been very consistent in developing warm
southerly flow Friday and continuing into Saturday. GFS is warmer
than than the ECMWF, but have trended a bit toward the warmer
solution and increased temperatures a few degrees over ensemble
guidance. Should be some welcome relief with temperatures well into
the 40s across the area and even around 50 in across parts of
central and eastern Missouri.
Carney
&&
.AVIATION: (For the 12z TAFs through 12z Tuesday Morning)
Issued at 501 AM CST Mon Jan 12 2015
Temperatures are starting to fall below zero as colder air rushes
into the area behind the departing storm system. Some lingering
drizzle and light snow will cause some concern for a few hours in
St. Louis. Trend should be for lifting ceiling and scattering by
evening as high pressure moves into the area. North wind will
increase this morning and become gusty to 25kts.
Specifics for KSTL:
Some light drizzle and flurries are expected for the next few
hours. Temperatures should drop below freezing in the next two
hours which could mean refreezing of moisture on runways. The rest
of the day should feature improving conditions in ceiling and an
eventual scattering/clearing this evening. North wind will
increase and gust to 25kt today as cold high pressure builds into
the region.
CVKING
&&
.PRELIMINARY POINT TEMPS/POPS:
Saint Louis 31 14 23 14 / 60 5 5 0
Quincy 19 3 18 8 / 10 0 0 0
Columbia 26 8 22 14 / 20 0 0 5
Jefferson City 30 10 23 13 / 40 0 0 5
Salem 32 18 24 13 / 50 5 0 5
Farmington 33 16 25 14 / 50 5 5 5
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Callaway
MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-Iron MO-
Jefferson MO-Lincoln MO-Madison MO-Montgomery MO-Osage MO-
Reynolds MO-St. Charles MO-St. Francois MO-St. Louis City
MO-St. Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.
WINTER WEATHER ADVISORY until 6 AM CST early this morning FOR
Audrain MO-Boone MO-Knox MO-Lewis MO-Marion MO-Moniteau MO-
Monroe MO-Pike MO-Ralls MO-Shelby MO.
IL...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Bond IL-
Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
Randolph IL-St. Clair IL-Washington IL.
WINTER WEATHER ADVISORY until 6 AM CST early this morning FOR
Adams IL-Brown IL-Pike IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
558 PM EST MON JAN 12 2015
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL LIFT NORTH OF THE AREA THROUGH THIS
EVENING AND IN ITS WAKE STRONG HIGH PRESSURE WILL BUILD ACROSS THE
AREA...REINFORCING THE CHILLY WEDGE LATER TONIGHT AND TUESDAY AND
THROUGH WEDNESDAY. AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE
AREA TUESDAY NIGHT AND WEDNESDAY...IT WILL ENHANCE THE LIFT AND
BRING A PERIOD OF LIGHT RAIN. AS TEMPERATURES FALL TO OR JUST
BELOW FREEZING LATE TUESDAY NIGHT...THIS RAIN MAY FREEZE ON
CONTACT WITH THE GROUND FOR PORTIONS OF OUR AREA. AT THIS TIME...
THE RISK IS HIGHEST ALONG AND NORTH OF A LINE FROM FLORENCE TO
WHITEVILLE LATE TUESDAY NIGHT AND WEDNESDAY MORNING. IF LATER
FORECASTS CONTINUE TO SHOW THIS SCENARIO...A WINTER WEATHER
ADVISORY WILL BE ISSUED FOR PORTIONS OF THE EASTERN CAROLINAS LATE
TONIGHT. LOW PRESSURE WILL DEEPEN OFF THE SOUTHEAST COAST THURSDAY
INTO FRIDAY BEFORE DRIER HIGH PRESSURE RETURNS FOR THE WEEKEND
WITH SUNNIER AND WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...AN AREA OF LOW PRESSURE IS CURRENTLY WORKING
ITS WAY NORTHWARD OFF THE CAROLINA COAST. THE LATEST RADAR TRENDS
AND HRRR RUNS SUGGEST THE SQUALL LINE ASSOCIATED WITH THIS FEATURE
WILL REMAIN JUST OFFSHORE. HOWEVER...PCPN WILL PERSIST INTO THIS
EVENING AS THE COASTAL FRONT REMAINS DRAPED ALONG OUR COAST. EXPECT
SHOWERS...POTENTIALLY HEAVY AT TIMES OVER THE CAPE FEAR REGION...AND
MORE LIGHT STRATIFORM RAIN INLAND WITHIN THE COOLER AIR MASS. AS THE
LOW TRACKS NORTH OF CAPE FEAR...WINDS WILL SWING AROUND TO THE
NORTHWEST AND HIGH PRESSURE NEAR THE GREAT LAKES WILL BEGIN BUILDING
SOUTHWARD INTO THE CAROLINAS. POPS WILL DECREASE FAIRLY RAPIDLY
AFTER MIDNIGHT FROM WEST TO EAST AS FCST SOUNDINGS DEPICT MID-LEVEL
DRYING. HOWEVER...PERIODS OF DRIZZLE AND PATCHY DENSE FOG WILL
DEVELOP OVERNIGHT AS THE 1000-700 MB LAYER REMAINS QUITE SATURATED.
GUIDANCE IS IN FAIRLY GOOD AGREEMENT FOR LOWS TONIGHT...GENERALLY
LOW TO MID 40S WITH UPPER 40S CLOSER TO THE BEACHES. STRONG COLD AIR
ADVECTION WILL CONTINUE THROUGH THE END OF THE PERIOD...WITH TEMPS
LIKELY FALLING THROUGH SUNRISE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...INCREASING PROSPECTS FOR FREEZING RAIN LATE
TUE NIGHT AND WED MORNING ALONG AND NORTH OF A LINE FROM FLO TO
CPC. SOUTH OF THE AFOREMENTIONED LINE...THE PRECIPITATION TYPE IS
EXPECTED TO BE RAIN. OTHERWISE LOW CLOUDS AND CHILLY TEMPS ARE
EXPECTED AS A STRONG SUBSIDENCE INVERSION LOCKS IN LOW-LEVEL
MOISTURE.
ARCTIC HIGH PRESSURE WILL ASSERT ITSELF THIS PERIOD AS THE CENTER
MOVES ACROSS THE GREAT LAKES AND NORTHEAST U.S. TUE AND WED. THIS
WILL ALLOW A STRONG WEDGE TO REASSERT ITSELF ACROSS THE CAROLINAS.
A MID-LEVEL SHORTWAVE WILL ENHANCE THE LIFT ACROSS THE AREA TUE
NIGHT AND WED AND THIS WILL BRING ANOTHER ROUND OF RAINFALL.
ADDITIONAL PRECIPITATION AMOUNTS DURING THIS TIME WILL NOT BE
ESPECIALLY HEAVY...AND MUCH OF THE RAIN WILL FALL WITH TEMPS ABOVE
THE FREEZING MARK. HOWEVER...IT ONLY TAKES A SMALL AMOUNT OF
ICE/GLAZE ON ROADWAYS TO CAUSE VERY DANGEROUS DRIVING CONDITIONS.
AT THIS TIME WE ARE FORECASTING LESS THAN A TENTH OF AN INCH OF
ICE WHERE FREEZING RAIN DOES OCCUR. WE WILL HOWEVER CONTINUE TO
MONITOR AS THE WEDGE IS TRENDING STRONGER AND THE MODELS COLDER
THAN 24 HOURS AGO. WINTER WEATHER ADVISORIES WILL LIKELY BE
REQUIRED FOR PORTIONS OF THE AREA WITH UPCOMING FORECASTS.
HIGHS TUE WILL BE IN THE 40S WITH PERHAPS SOME LOWER 50S ACROSS
COASTAL SOUTH CAROLINA AS MORNING TEMPS HOLD STEADY OR RISE NO
MORE THAN A DEGREE OR TWO THROUGH THE AFTERNOON AS BRISK NE WINDS
MAKE IT FEEL VERY WINTER-LIKE. TEMPS TUE EVE WILL BE ABOVE
FREEZING...BUT LOWS ARE EXPECTED TO DROP TO OR JUST BELOW
FREEZING FROM FLO TO CPC NORTHWARD...LATE TUE NIGHT...WITH MID 30S
AT THE COAST. TEMPS WILL STRUGGLE THROUGH THE 30S ON WED AND IT
MAY TAKE SOME NORTHERN AREAS A GOOD PART OF THE MORNING TO RISE
ABOVE FREEZING. SOME LOWER 40S ARE POSSIBLE ALONG THE SOUTH SANTEE
RIVER AREA AND THE IMMEDIATE COAST.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...PHASING PIECES OF ENERGY OVERHEAD LATE
THURSDAY WILL DRIVE CYCLOGENESIS WELL OFF THE SOUTHEAST COAST LATE
THURSDAY INTO FRIDAY. GUIDANCE CONTINUES TO INDICATE MOST OF THE
PRECIP ASSOCIATED WITH THIS DEVELOPING LOW PRESSURE WILL REMAIN
OFFSHORE...AND WILL CARRY ONLY CHC POP THURSDAY BEFORE RAMPING DOWN
QUICKLY FRIDAY MORNING. THEREAFTER...HIGH PRESSURE BUILDS INTO THE
MID-ATLANTIC AND SHIFTS OFFSHORE DURING THE WKND. THIS OCCURS AT THE
SAME TIME THAT MID-LEVEL FLOW FLATTENS...AND THIS SHOULD BRING A
PERIOD OF MUCH NICER WEATHER WITH SUNSHINE AND TEMPS RECOVERING TO
ABOVE CLIMO VALUES FOR THE WKND. RETURN FLOW ON SUNDAY MAY PUMP
ENOUGH MOISTURE INTO THE REGION TO SPAWN A FEW SHOWERS LATE
SUNDAY/SUNDAY NIGHT AHEAD OF THE NEXT COLD FRONT...BUT WILL MAINTAIN
INHERITED SILENT POP FOR NOW WITH COOLER AND DRY CONDITIONS FOR
MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SUNDAY/...
AS OF 00Z...MOST OF THE PRECIP HAS MOVED OUT OF THE REGION...WITH
SOME LINGERING RAIN AT ILM THAT WILL LAST ANOTHER HOUR OR TWO.
BEHIND IT...WEDGE SETTING BACK UP WITH NORTHWEST FLOW COMMENCING.
CEILINGS AND VIS WILL LIKELY GO DOWN TO IFR/LIFR IN ONLY A FEW HOURS
AT ALL LOCATIONS...INLAND WILL BE THE WORST. A NORTHERLY GRADIENT
WILL INCREASE TOWARD MORNING WHICH WILL PROBABLY BRING VISIBILITIES
UP BUT CEILINGS WILL LIKELY REMAIN IFR. TUESDAY...WINDS WILL
CONTINUE TO VEER TO THE NORTHEAST WITH IFR CEILINGS CONTINUING.
EXTENDED OUTLOOK...RAIN AND MVFR/IFR CONDITIONS WILL PREVAIL
POSSIBLY THROUGH WED AS A COOL WEDGE REMAINS LOCKED IN PLACE OVER
THE CAROLINAS. RAIN/MVFR ON THU. VFR FRI AND SAT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...A SMALL CRAFT ADVISORY REMAINS IN EFFECT
FOR OUR COASTAL WATERS. EXPECT SEAS TO REMAIN IN THE 4-6 FT RANGE
THROUGH THIS EVENING...POTENTIALLY HIGHER ACROSS THE OUTER
PORTIONS OF AMZ250/252. AN AREA OF LOW PRESSURE HAS DEVELOPED
ALONG THE COASTAL FRONT AND IS MOVING NORTHWARD OVER THE WATERS.
THUS MORE SHOWERS AND ISOLATED TSTMS ARE EXPECTED THROUGH THIS
EVENING. SOUTH WINDS 15-20 KT WILL VEER TO THE SOUTHWEST 10-15 KT
TONIGHT...AND THEN NORTHWEST AROUND 10 KT AFTER MIDNIGHT. THIS
OFFSHORE FLOW SHOULD ALLOW SEAS TO BRIEFLY SUBSIDE BELOW SCA
CRITERIA...BUT REMAIN IN THE 3-5 FT RANGE. THE GRADIENT WILL
TIGHTEN EARLY TUE MORNING AS HIGH PRESSURE WEDGES INTO THE
CAROLINAS...PRODUCING NORTH WINDS AROUND 15 KT BY THE END OF THE
PERIOD.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED
FOR MUCH OF THE PERIOD AS ARCTIC HIGH PRESSURE ASSERTS ITSELF
SOUTHWARD ACROSS THE AREA. THIS WILL DRAMATICALLY TIGHTEN THE
PRESSURE GRADIENT AS A NE SURGE BRINGS ANOTHER LENGTHY PERIOD OF
SMALL CRAFT ADVISORY CONDITIONS. THE WIND DIRECTION WILL BE NE
THROUGH THE PERIOD...UP TO AROUND 25 KT WITH GUSTS AROUND 30 KT.
SEAS WILL BE UP TO 6 TO 9 FT. THE WORST OF THE MARINE CONDITIONS
ARE EXPECTED TO DEVELOP LATER TUE MORNING THROUGH TUE NIGHT.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...LOW PRESSURE DEVELOPING OFFSHORE ON
THURSDAY WILL CAUSE A SLOWLY TIGHTENING GRADIENT...WITH NORTHERLY
WINDS INCREASING TO 15-20 KTS THURSDAY NIGHT INTO FRIDAY. AS THIS
LOW PULLS AWAY DURING FRIDAY...HIGH PRESSURE WILL RIDGE TOWARDS
THE AREA FROM THE SOUTHWEST. WINDS WILL EASE TO LESS THAN 10 KTS
DURING SATURDAY WHILE MAINTAINING A NORTHERLY DIRECTION...BEFORE
BECOMING LIGHT AND VARIABLE AT THE END OF THE PERIOD. HIGHEST SEAS
WILL BE LATE THURSDAY AND MUCH OF FRIDAY DURING THE HIGHEST
WINDS...WITH 3-5 FT WAVE HEIGHTS EXPECTED...HIGHEST RIGHT ALONG
THE 20 NM BOUNDARY. SEAS WILL DROP QUICKLY ON SATURDAY TO 2-3 FT
THANKS TO THE DECREASING WINDS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...BJR
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
326 PM EST MON JAN 12 2015
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL LIFT NORTH OF THE AREA THROUGH THIS
EVENING AND IN ITS WAKE STRONG HIGH PRESSURE WILL BUILD ACROSS THE
AREA...REINFORCING THE CHILLY WEDGE LATER TONIGHT AND TUESDAY AND
THROUGH WEDNESDAY. AS AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE
AREA TUESDAY NIGHT AND WEDNESDAY...IT WILL ENHANCE THE LIFT AND
BRING A PERIOD OF LIGHT RAIN. AS TEMPERATURES FALL TO OR JUST
BELOW FREEZING LATE TUESDAY NIGHT...THIS RAIN MAY FREEZE ON
CONTACT WITH THE GROUND FOR PORTIONS OF OUR AREA. AT THIS TIME...
THE RISK IS HIGHEST ALONG AND NORTH OF A LINE FROM FLORENCE TO
WHITEVILLE LATE TUESDAY NIGHT AND WEDNESDAY MORNING. IF LATER
FORECASTS CONTINUE TO SHOW THIS SCENARIO...A WINTER WEATHER
ADVISORY WILL BE ISSUED FOR PORTIONS OF THE EASTERN CAROLINAS LATE
TONIGHT. LOW PRESSURE WILL DEEPEN OFF THE SOUTHEAST COAST THURSDAY
INTO FRIDAY BEFORE DRIER HIGH PRESSURE RETURNS FOR THE WEEKEND
WITH SUNNIER AND WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...AN AREA OF LOW PRESSURE IS CURRENTLY WORKING
ITS WAY NORTHWARD OFF THE CAROLINA COAST. THE LATEST RADAR TRENDS
AND HRRR RUNS SUGGEST THE SQUALL LINE ASSOCIATED WITH THIS FEATURE
WILL REMAIN JUST OFFSHORE. HOWEVER...PCPN WILL PERSIST INTO THIS
EVENING AS THE COASTAL FRONT REMAINS DRAPED ALONG OUR COAST. EXPECT
SHOWERS...POTENTIALLY HEAVY AT TIMES OVER THE CAPE FEAR REGION...AND
MORE LIGHT STRATIFORM RAIN INLAND WITHIN THE COOLER AIR MASS. AS THE
LOW TRACKS NORTH OF CAPE FEAR...WINDS WILL SWING AROUND TO THE
NORTHWEST AND HIGH PRESSURE NEAR THE GREAT LAKES WILL BEGIN BUILDING
SOUTHWARD INTO THE CAROLINAS. POPS WILL DECREASE FAIRLY RAPIDLY
AFTER MIDNIGHT FROM WEST TO EAST AS FCST SOUNDINGS DEPICT MID-LEVEL
DRYING. HOWEVER...PERIODS OF DRIZZLE AND PATCHY DENSE FOG WILL
DEVELOP OVERNIGHT AS THE 1000-700 MB LAYER REMAINS QUITE SATURATED.
GUIDANCE IS IN FAIRLY GOOD AGREEMENT FOR LOWS TONIGHT...GENERALLY
LOW TO MID 40S WITH UPPER 40S CLOSER TO THE BEACHES. STRONG COLD AIR
ADVECTION WILL CONTINUE THROUGH THE END OF THE PERIOD...WITH TEMPS
LIKELY FALLING THROUGH SUNRISE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...INCREASING PROSPECTS FOR FREEZING RAIN LATE
TUE NIGHT AND WED MORNING ALONG AND NORTH OF A LINE FROM FLO TO
CPC. SOUTH OF THE AFOREMENTIONED LINE...THE PRECIPITATION TYPE IS
EXPECTED TO BE RAIN. OTHERWISE LOW CLOUDS AND CHILLY TEMPS ARE
EXPECTED AS A STRONG SUBSIDENCE INVERSION LOCKS IN LOW-LEVEL
MOISTURE.
ARCTIC HIGH PRESSURE WILL ASSERT ITSELF THIS PERIOD AS THE CENTER
MOVES ACROSS THE GREAT LAKES AND NORTHEAST U.S. TUE AND WED. THIS
WILL ALLOW A STRONG WEDGE TO REASSERT ITSELF ACROSS THE CAROLINAS.
A MID-LEVEL SHORTWAVE WILL ENHANCE THE LIFT ACROSS THE AREA TUE
NIGHT AND WED AND THIS WILL BRING ANOTHER ROUND OF RAINFALL.
ADDITIONAL PRECIPITATION AMOUNTS DURING THIS TIME WILL NOT BE
ESPECIALLY HEAVY...AND MUCH OF THE RAIN WILL FALL WITH TEMPS ABOVE
THE FREEZING MARK. HOWEVER...IT ONLY TAKES A SMALL AMOUNT OF
ICE/GLAZE ON ROADWAYS TO CAUSE VERY DANGEROUS DRIVING CONDITIONS.
AT THIS TIME WE ARE FORECASTING LESS THAN A TENTH OF AN INCH OF
ICE WHERE FREEZING RAIN DOES OCCUR. WE WILL HOWEVER CONTINUE TO
MONITOR AS THE WEDGE IS TRENDING STRONGER AND THE MODELS COLDER
THAN 24 HOURS AGO. WINTER WEATHER ADVISORIES WILL LIKELY BE
REQUIRED FOR PORTIONS OF THE AREA WITH UPCOMING FORECASTS.
HIGHS TUE WILL BE IN THE 40S WITH PERHAPS SOME LOWER 50S ACROSS
COASTAL SOUTH CAROLINA AS MORNING TEMPS HOLD STEADY OR RISE NO
MORE THAN A DEGREE OR TWO THROUGH THE AFTERNOON AS BRISK NE WINDS
MAKE IT FEEL VERY WINTER-LIKE. TEMPS TUE EVE WILL BE ABOVE
FREEZING...BUT LOWS ARE EXPECTED TO DROP TO OR JUST BELOW
FREEZING FROM FLO TO CPC NORTHWARD...LATE TUE NIGHT...WITH MID 30S
AT THE COAST. TEMPS WILL STRUGGLE THROUGH THE 30S ON WED AND IT
MAY TAKE SOME NORTHERN AREAS A GOOD PART OF THE MORNING TO RISE
ABOVE FREEZING. SOME LOWER 40S ARE POSSIBLE ALONG THE SOUTH SANTEE
RIVER AREA AND THE IMMEDIATE COAST.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...PHASING PIECES OF ENERGY OVERHEAD LATE
THURSDAY WILL DRIVE CYCLOGENESIS WELL OFF THE SOUTHEAST COAST LATE
THURSDAY INTO FRIDAY. GUIDANCE CONTINUES TO INDICATE MOST OF THE
PRECIP ASSOCIATED WITH THIS DEVELOPING LOW PRESSURE WILL REMAIN
OFFSHORE...AND WILL CARRY ONLY CHC POP THURSDAY BEFORE RAMPING DOWN
QUICKLY FRIDAY MORNING. THEREAFTER...HIGH PRESSURE BUILDS INTO THE
MID-ATLANTIC AND SHIFTS OFFSHORE DURING THE WKND. THIS OCCURS AT THE
SAME TIME THAT MID-LEVEL FLOW FLATTENS...AND THIS SHOULD BRING A
PERIOD OF MUCH NICER WEATHER WITH SUNSHINE AND TEMPS RECOVERING TO
ABOVE CLIMO VALUES FOR THE WKND. RETURN FLOW ON SUNDAY MAY PUMP
ENOUGH MOISTURE INTO THE REGION TO SPAWN A FEW SHOWERS LATE
SUNDAY/SUNDAY NIGHT AHEAD OF THE NEXT COLD FRONT...BUT WILL MAINTAIN
INHERITED SILENT POP FOR NOW WITH COOLER AND DRY CONDITIONS FOR
MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...THE COASTAL FRONT REMAINS DRAPED ACROSS THE CWA
BETWEEN THE INLAND AND COASTAL TERMINALS. THE LOWEST PREDOMINATE
CONDITIONS...LIFR/IFR...ARE STILL WEST OF THE FRONT AT KFLO/KLBT.
AT THE COAST...EXPECT MAINLY MVFR CONDITIONS WITH TEMPO IFR AS
SHOWERS MOVE OVERHEAD. CONDITIONS WILL DETERIORATE TONIGHT AS THE
FRONT MOVES BACK OFFSHORE. LOOK FOR IFR/LIFR CIGS WITH PERIODS OF
DRIZZLE AND MVFR/IFR VSBYS TONIGHT ACROSS THE AREA. WINDS WILL
SHIFT TO THE NORTHWEST AND THEN NORTH OVERNIGHT INTO TUE
MORNING...BECOMING 10-15 KT DURING THE DAY. HAVE CARRIED IFR CIGS
THROUGH THE END OF THE PERIOD AT THE COAST...WHILE THE INLAND
TERMINALS MAY SEE A SLIGHT IMPROVEMENT IN CIGS BY LATE MORNING.
EXTENDED OUTLOOK...RAIN AND MVFR/IFR CONDITIONS WILL PREVAIL
POSSIBLY THROUGH WED AS A COOL WEDGE REMAINS LOCKED IN PLACE OVER
THE CAROLINAS. RAIN/MVFR ON THU. VFR FRI AND SAT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...A SMALL CRAFT ADVISORY REMAINS IN EFFECT
FOR OUR COASTAL WATERS. EXPECT SEAS TO REMAIN IN THE 4-6 FT RANGE
THROUGH THIS EVENING...POTENTIALLY HIGHER ACROSS THE OUTER
PORTIONS OF AMZ250/252. AN AREA OF LOW PRESSURE HAS DEVELOPED
ALONG THE COASTAL FRONT AND IS MOVING NORTHWARD OVER THE WATERS.
THUS MORE SHOWERS AND ISOLATED TSTMS ARE EXPECTED THROUGH THIS
EVENING. SOUTH WINDS 15-20 KT WILL VEER TO THE SOUTHWEST 10-15 KT
TONIGHT...AND THEN NORTHWEST AROUND 10 KT AFTER MIDNIGHT. THIS
OFFSHORE FLOW SHOULD ALLOW SEAS TO BRIEFLY SUBSIDE BELOW SCA
CRITERIA...BUT REMAIN IN THE 3-5 FT RANGE. THE GRADIENT WILL
TIGHTEN EARLY TUE MORNING AS HIGH PRESSURE WEDGES INTO THE
CAROLINAS...PRODUCING NORTH WINDS AROUND 15 KT BY THE END OF THE
PERIOD.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED
FOR MUCH OF THE PERIOD AS ARCTIC HIGH PRESSURE ASSERTS ITSELF
SOUTHWARD ACROSS THE AREA. THIS WILL DRAMATICALLY TIGHTEN THE
PRESSURE GRADIENT AS A NE SURGE BRINGS ANOTHER LENGTHY PERIOD OF
SMALL CRAFT ADVISORY CONDITIONS. THE WIND DIRECTION WILL BE NE
THROUGH THE PERIOD...UP TO AROUND 25 KT WITH GUSTS AROUND 30 KT.
SEAS WILL BE UP TO 6 TO 9 FT. THE WORST OF THE MARINE CONDITIONS
ARE EXPECTED TO DEVELOP LATER TUE MORNING THROUGH TUE NIGHT.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...LOW PRESSURE DEVELOPING OFFSHORE ON
THURSDAY WILL CAUSE A SLOWLY TIGHTENING GRADIENT...WITH NORTHERLY
WINDS INCREASING TO 15-20 KTS THURSDAY NIGHT INTO FRIDAY. AS THIS
LOW PULLS AWAY DURING FRIDAY...HIGH PRESSURE WILL RIDGE TOWARDS
THE AREA FROM THE SOUTHWEST. WINDS WILL EASE TO LESS THAN 10 KTS
DURING SATURDAY WHILE MAINTAINING A NORTHERLY DIRECTION...BEFORE
BECOMING LIGHT AND VARIABLE AT THE END OF THE PERIOD. HIGHEST SEAS
WILL BE LATE THURSDAY AND MUCH OF FRIDAY DURING THE HIGHEST
WINDS...WITH 3-5 FT WAVE HEIGHTS EXPECTED...HIGHEST RIGHT ALONG
THE 20 NM BOUNDARY. SEAS WILL DROP QUICKLY ON SATURDAY TO 2-3 FT
THANKS TO THE DECREASING WINDS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...BJR
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
254 PM EST MON JAN 12 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL TRACK NORTHEAST OVER THE
EASTERN CAROLINAS AND MID ATLANTIC COAST THROUGH TONIGHT. A SERIES
OF UPPER LEVEL DISTURBANCES WILL MAINTAIN AN UNSETTLED WEATHER
PATTERN OVER THE CAROLINAS THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1040 AM MONDAY...
THE SHIELD OF RAIN THAT MOVED ACROSS CENTRAL NC DURING THIS
MORNING`S COMMUTE HAS MOVED EAST OF I-95...AS THE ASSOC LOW-MID
LEVEL MESO-VORT IS NOW LIFTING UP ACROSS NE NC ATTM (PER 88D). FOR
THE REST OF THIS MORNING...THE RAIN WILL BE MORE PATCHY IN NATURE
ACROSS THE TRIANGLE AND TRIAD REGIONS...WITH SYNOPTIC SCALE LIFT
WEAKENING IN THE WAKE OF THE AFOREMENTIONED DEPARTING VORT FEATURE.
MEANWHILE... WE`RE KEEPING OUR EYES ON THE ANOTHER LOW-LEVEL WAVE
AND AREA OF RAIN LIFTING NE ACROSS ERN GA AND SRN SC...BASICALLY
LIFTING NE UP ALONG THE STATIONARY SFC BOUNDARY THAT`S PRESENTLY
STRETCHING FROM COASTAL SC NWD ALONG THE NC HWY 17 CORRIDOR. CURRENT
HIRES NEAR-TERM GUIDANCE SUGGESTS THIS RAIN WILL MOVE UP INTO E-
CENTRAL AND ERN NC BY MID-DAY OR EARLY AFTERNOON...BASICALLY CATCHING
UP TO AND FILLING IN BEHIND THE RAIN THAT`S PRESENTLY FALLING EAST
OF I-95. AS SUCH...LOOK FOR A WET AFTERNOON ACROSS THE ERN HALF OF
OUR CWA...MAINLY EAST OF THE US-1 CORRIDOR...BUT ESP ALONG THE I-95
CORRIDOR AND EWD. WHILE SOME THUNDER CAN`T BE RULED OUT EARLY THIS
AFTERNOON ALONG THE SRN I-95 CORRIDOR WHEN THE RAIN SHIELD FIRST
MOVES UP IN THE SE NC...THE LATEST MESO-ANALYSIS AND HRRR SUGGEST
THE BEST LAPSE RATES AND INSTABILITY SHOULD REMAIN ALONG OR JUST OFF
THE COAST...WILL MONITOR. WHILE THE BULK OF THE RAIN...AND HEAVIEST
RAIN SHOULD REMAIN EAST OF US-1...LIGHT RAIN OR PATCHY DRIZZLE WILL
STILL BE POSSIBLE WEST OF US-1 THROUGH THE DAY. TEMPS WILL VARY
QUITE A BIT FROM NW TO SE: COOLEST NW (HIGHS ONLY REACHING THE LOW
40S)...AND WARMEST SE NEAR THE SFC WAVE AND BOUNDARY (MID-50S).
TONIGHT...A NEARLY SATURATED AIR MASS WILL REMAIN IN PLACE THOUGH
PRECIP WILL BE CONFINED TO MAINLY DRIZZLE AND SPOTS OF LIGHT RAIN AS
LIFT THROUGH THE COLUMN RATHER WEAK. A COLD FRONT ASSOCIATED WITH A
S/W CROSSING THE GREAT LAKES INTO SOUTHERN NEW ENGLAND WILL DRAG A
COLD FRONT TOWARD CENTRAL NC THIS EVENING AND INTO OUR NORTHERN
COUNTIES AFTER MIDNIGHT. CONVERGENCE ALONG THIS BOUNDARY MAY ENHANCE
THE SPOTTY LIGHT RAIN OR DRIZZLE COVERAGE OVERNIGHT. TEMPS THIS
EVENING WILL BE JUST A FEW DEGREES COOLER THAN AFTERNOON TEMPS. THE
PASSAGE OF THE COLD FRONT ACROSS THE NORTH SHOULD CAUSE TEMPS TO
COOL DURING THE PRE-DAWN HOURS. MIN TEMPS MID 30S ACROSS THE FAR
NORTH TO THE LOWER 40S FAR SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...
TUESDAY:
A 1045 MB HIGH OVER THE GREAT LAKES WILL WEAKEN SLIGHTLY AS IT
SLIDES EASTWARD OVER NORTHERN NEW YORK STATE. THIS HIGH IS STRONG
ENOUGH AND IN A GOOD LOCATION FOR A CLASSICAL COLD AIR DAMMING
SCENARIO TO BEGIN TO SET UP OVER CENTRAL NORTH CAROLINA AS A WEDGE
FRONT BEGINS TO BUILD INTO THE AREA FROM THE NORTH. LOW LEVEL
MOISTURE REMAINS VERY HIGH BUT THE UPPER LEVELS WILL DRY OUT AND A
PERIOD DURING THE MORNING OF ISENTROPIC DOWNGLIDE WILL HELP KEEP
PRECIPITATION POTENTIAL DOWN ALTHOUGH SOME LIGHT DRIZZLE CANNOT BE
RULED OUT. WITH COLD AIR DIVING IN FROM THE NORTH...EXPECT HIGHS TO
OCCUR ON MIDNIGHT TUESDAY MORNING WITH UPPER 30S TO LOW 40S NW TO
SE. TEMPS WILL THEN STEADILY DROP THROUGHOUT THE DAY AND EVENTUALLY
TO VALUES BELOW FREEZING FROM NORTH TO SOUTH BEGINNING AFTER OOZ
WEDNESDAY.
TUESDAY NIGHT AND WEDNESDAY MORNING:
AFTER 00Z WEDNESDAY ISENTROPIC LIFT BEGINS TO INCREASE UP TO 850 MB
OR SO AND THEN BY 12Z EVEN FURTHER WITH MAXIMUM OMEGA AT 750 MB AND
WEAKER LIFT UP TO 600MB. DURING THIS TIME A WAVE OF LOW PRESSURE
MOVES UP THE SOUTHEAST COAST SUPPLYING SOME MOISTURE TO THE AREA
WHICH WILL BE MOST PREVALENT IN THE SOUTHEASTERN COUNTIES OF THE
CWA. THERE IS NOT MUCH CONFIDENCE IN THE FORECAST WITH REGARD TO
PRECIPIATION AMOUNTS AND THE NORTHWARD EXTENT OF THE PRECIPIATION.
THE NAM IS CURRENTLY THE MOST BULLISH ON QPF AS IT HAS SOME
INCREASED TROUGHING INLAND WHICH HELPS TO PRODUCE MORE QPF IN THE
MODEL. THE GFS AND ECMWF OFFER MUCH DRIER SOLUTIONS AT THIS TIME.
FOR THE CURRENT FORECAST PACKAGE WILL HAVE 1-2 TENTHS OF AN INCH OF
LIQUID ACROSS THE SOUTH TUESDAY NIGHT INTO WEDNESDAY WITH ONLY A
COUPLE OF HUNDREDTHS OF AN INCH IN THE NORTHWEST PIEDMONT.
WITH THE PRECIPIATION FORECAST IN PLACE...THE NEXT QUESTION WILL BE
WITH REGARD TO TEMPERATURES AND THE SOUTHWARD MARCH OF FREEZING
CONDITIONS. FREEZING TEMPS WILL BEGIN TO ENTER NORTHERN COUNTIES
AROUND 00Z WEDNESDAY AND SLOWLY WORK SOUTHWARD REACHING THE SOUTHERN
COUNTIES BY 9-12Z. WETBULB TEMPERATURES ALSO REACH THE FREEZING MARK
IN MOST COUNTIES WITH THE POSSIBILITY OF THE EXTREME SOUTHERN TIER
REMAINING ABOVE FREEZING BUT EVEN THE 12Z RUN OF THE ECMWF...WHICH
HAD BEEN WARMER...HAS COME IN WITH FREEZING WETBULB TEMPS THROUGH
THE SOUTHERN BOUNDARY OF THE CWA.
PHASING OF THE PRECIPITATION AND FREEZING TEMPERATURE FORECASTS
SHOWS THAT THE MOST LIKELY AREA TO HAVE ANY IMPACTS IN REGARDS TO
FREEZING RAIN WOULD BE THE SOUTHEASTERN COUNTIES WITH A POTENTIAL
SWEET SPOT FOR THE MOST ACCUMULATION OF ICE OCCURRING ROUGHLY ALONG
THE I-95 CORRIDOR BETWEEN FAYETTEVILLE AND ROCKY MOUNT. WITH WEAK
RAIN RATES AND LIMITED TIME BELOW FREEZING...ICE ACCRUAL VALUES
SHOULD BE AT MOST A FEW HUNDREDTHS OF AN INCH WITH CLOSER TO 0.05
INCHES IN THE AFOREMENTIONED SWEET SPOT.
HOW CONFIDENT IS THE FORECAST? WITH MODELS TRENDING COLDER...THERE
IS INCREASING CONFIDENCE THAT WE WILL GET TEMPERATURES LOW ENOUGH TO
SUPPORT FREEZING RAIN. THAT BEING SAID...THE PRECIPIATION FORECAST
REMAINS THE LARGEST VARIABLE. A SHIFT IN TRACK OF THE OFFSHORE LOW
COULD RESULT IN A CHANGE IN QPF VALUES ONE WAY OR THE OTHER AS WELL
AS THE DISTRIBUTION OF PRECIPIATION. ALSO A CHANGE IN THE AMOUNT OF
TIME THAT FREEZING TEMPERATURE AND PRECIPIATION COMBINE WOULD ALSO
AFFECT ICE ACCRUAL VALUES AND ULTIMATELY IMPACTS. FURTHER DETAILS
WILL BEGIN TO EMERGE AS SOME OF THE HIGHER RESOLUTION MODELS BEGIN
TO PICK UP THE SYSTEM.
WEDNESDAY AFTERNOON/NIGHT:
AFTER 18Z WEDNESDAY THE TEMPERATURES WILL RETURN TO ABOVE FREEZING
LEVELS AND PRECIPITATION FOR THE MOST PART WILL MOVE OFF TO THE EAST
WITH THE EXCEPTION OF EASTERN COUNTIES THAT COULD SEE SOME LINGERING
LIGHT RAIN OR DRIZZLE INTO WEDNESDAY NIGHT. HIGHS WEDNESDAY IN THE
MID TO UPPER 30S WITH LOWS IN THE LOW TO MID 30S WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...
A POSITIVE TILT TROUGH WILL APPROACH CENTRAL NC FROM THE WEST THU
AND EXIT THE REGION BY EARLY FRIDAY. MEDIUM RANGE GUIDANCE STILL
OFFER VARYING SOLUTIONS REGARDING THE PRECIP SHIELD ASSOCIATED WITH
THIS SYSTEM WITH THE GFS SUPPRESSED TO THE SOUTH OF OUR REGION AND
ECMWF DEPICTING THE NORTHERN EDGE OF THE PRECIP OVER THE SOUTH AND
EAST SECTIONS OF OUR FORECAST AREA. THE MORE NORTHERN EXTENT OF THE
ECMWF PRECIP LIKELY DUE TO THE TROUGH BEING SLIGHTLY MORE AMPLIFIED
COMPARED TO THE GFS. FOR NOW...WILL MAINTAIN CHANCE POPS ACROSS THE
SOUTH AND EAST AND SLIGHT CHANCE POPS ACROSS THE NW. EXTENSIVE CLOUD
COVER AND COOL NLY LOW LEVEL FLOW WILL KEEP HIGH TEMPS SEVERAL
DEGREES BELOW NORMAL. HIGHS THU MID-UPPER 40S.
A S/W RIDGE WILL BUILD INTO OUR REGION BEHIND THE EXITING TROUGH
FRIDAY AND CROSS THE REGION SATURDAY. THIS WEATHER SYSTEM WILL
INITIATE A DRY WEATHER REGIME WITH MODERATING TEMPERATURES. BY
SATURDAY...EXPECT HIGH TEMPS CLOSER TO NORMAL FOR MID JANUARY WITH
HIGHS RANGING FROM UPPER 40S TO AROUND 50 NORTH TO THE LOWER 50S
SOUTH. THE WARMING TREND CONTINUES INTO SUNDAY AS WLY FLOW
DOMINATES. AFTERNOON TEMPS HAVE THE POTENTIAL TO REACH WELL INTO THE
50S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1250 PM MONDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: CONTINUED IFR/LIFR CONDITIONS
AT ALL SITES... AND LOW LEVEL WIND SHEAR AT RDU/RWI/FAY NEXT 5 HOURS.
IFR/LIFR AVIATION CONDITIONS WILL PERSIST AT ALL CENTRAL NC TAF
SITES THROUGH EARLY AFTERNOON TUESDAY. A DEEPLY MOIST AND UNSETTLED
PATTERN IS IN PLACE WITH DISTURBANCES PASSING ALOFT... KEEPING A
GOOD CHANCE OF LIGHT RAIN OR DRIZZLE INTO EARLY THIS EVENING... WITH
THE BEST RAIN COVERAGE AFFECTING RDU/RWI/FAY AS A LOW PRESSURE AREA
TRACKS TO THE NE OVER COASTAL NC. WIDESPREAD IFR/LIFR FOG WILL
REMAIN PREVALENT AT ALL SITES THROUGH THIS EVENING... WITH LIGHT AND
VARIABLE WINDS. A COLD FRONT NOW OVER THE OH VALLEY WILL PUSH
SOUTHEAST THROUGH NC LATE TONIGHT... MAINLY BETWEEN 05Z AND 09Z...
AND WITH ITS PASSAGE THE SURFACE WINDS WILL SHIFT AROUND TO NORTH
THEN NORTHEAST... SUSTAINED NEAR 7-12 KTS WITH SOME GUSTS POSSIBLE
LATE TONIGHT INTO TUE MORNING. PATCHY DRIZZLE IS EXPECTED JUST
BEHIND THE FRONT LATE TONIGHT THROUGH THE END OF THE TAF VALID
PERIOD... WITH CIGS LIKELY TO REMAIN IFR/LIFR.
LOOKING BEYOND 18Z TUE: POOR AVIATION CONDITIONS WILL DOMINATE
THROUGH AT LEAST WED... WITH VERY MOIST AIR HOLDING IN PLACE FROM
THE SURFACE UP THROUGH THE LOWEST 7-10 THOUSAND FT... YIELDING
MAINLY IFR/LIFR CIGS. ANY PRECIP SHOULD BE VERY LIGHT THROUGH TUE
AFTERNOON... THEN A PASSING DISTURBANCE MAY BRING A BETTER CHANCE OF
SUB-VFR VSBYS IN RAIN AT FAY/RWI TUE NIGHT/WED MORNING. FAY/RWI MAY
SEE ANOTHER RAIN CHANCE EARLY THU WITH ANOTHER PASSING DISTURBANCE.
IMPROVEMENT TO VFR IS EXPECTED THU NIGHT AS A MID LEVEL TROUGH MOVES
OVERHEAD AND TO OUR EAST... THEN VFR CONDITIONS SHOULD DOMINATE
FRI/SAT AS HIGH PRESSURE NOSES IN FROM THE SW. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...NP/WSS
SHORT TERM...ELLIS
LONG TERM...WSS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
112 PM EST MON JAN 12 2015
.SYNOPSIS...
RAIN WILL CONTINUE ACROSS THE CAROLINAS AS A COASTAL FRONT PUSHES
WESTWARD OVER THE COAST WITH SUBTROPICAL AIR SPREADING ONTO THE
BEACHES. COOLER CONDITIONS WILL PERSIST INLAND AS A WEDGE OF
HIGH PRESSURE REMAINS ACROSS THE INTERIOR CAROLINAS. STRONG HIGH
PRESSURE WILL BUILD DOWN INTO THE CAROLINAS LATE MONDAY THROUGH
WEDNESDAY REINFORCING THE WEDGE ACROSS THE CAROLINAS. LOW PRESSURE
WILL DEEPEN OFF THE SOUTHEAST COAST THURSDAY INTO FRIDAY BEFORE
DRIER HIGH PRESSURE RETURNS FOR THE WEEKEND WITH SUNNIER AND
WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM MONDAY...THE COASTAL FRONT CONTINUES TO BISECT OUR
CWA THIS AFTERNOON...HAVING JUST REACHED CONWAY AND WHITEVILLE
BASED ON THE LATEST SURFACE OBS. THE RADAR DEPICTS WIDESPREAD RAIN
SHOWERS WITH A FEW ISOLATED TSTMS...ALTHOUGH THE LIGHTNING INLAND
HAS SUBSIDED SOMEWHAT AS THE PCPN IS NOW TAKING ON A MORE STRATIFORM
APPEARANCE ON RADAR. WILL CARRY CATEGORICAL POPS THROUGH THE AFTN
HOURS AS A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT AND MOVES
NORTHEAST UP THE CAROLINA COAST. THE HRRR CONTINUES TO DEPICT THE
EVOLUTION OF PCPN TODAY FAIRLY WELL...SO HAVE ADVERTISED THE
HEAVIEST RAIN OVER THE CAPE FEAR REGION INTO THIS EVENING. ADDITIONAL
RAINFALL AROUND ONE HALF INCH IS EXPECTED THROUGH TONIGHT. THERE
IS THE POSSIBILITY FOR LOCALIZED MINOR FLOODING...ESPECIALLY IN
AREAS THAT RECEIVED HEAVIER PCPN EARLIER...LIKE WEST OF I-95 OR
ALONG THE GRAND STRAND.
AS THE LOW TRACKS NORTH OF CAPE FEAR...WINDS WILL SWING AROUND TO
THE NORTHWEST AND HIGH PRESSURE NEAR THE GREAT LAKES WILL BEGIN
BUILDING SOUTHWARD INTO THE CAROLINAS. POPS DECREASE AFTER
MIDNIGHT AS FCST SOUNDINGS DEPICT MID-LEVEL DRYING. HOWEVER...
PERIODS OF DRIZZLE AND PATCHY FOG WILL PERSIST OVERNIGHT AS THE
1000-700 MB LAYER REMAINS SATURATED. GUIDANCE REMAINS IN FAIRLY
GOOD AGREEMENT FOR LOWS TONIGHT...GENERALLY LOW TO MID 40S WITH
UPPER 40S CLOSER TO THE BEACHES.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM MONDAY...STRONG HIGH PRESSURE WILL BUILD DOWN FROM
THE NORTH THROUGH MID WEEK HELPING TO REINFORCE THE WEDGE IN PLACE
ACROSS THE CAROLINAS AND CREATING CLOUDY DAMP AND COOL WEATHER
TUES INTO WED. SHALLOW COOL NE WINDS NEAR THE SFC WILL BE OVERRUN
BY SW WINDS ALOFT HELPING TO LOCK IN LOW CLOUDS AND KEEP CHC OF
RAIN IN THE FORECAST. A SHORTWAVE WILL RIDE ACROSS THE CAROLINAS
OVERNIGHT TUES FURTHER ENHANCING LIFT AND INCREASING THE CHC OF
RAIN. OVERALL EXPECT CLOUDY AND COOL WEATHER WITH INTERMITTENT
RAIN THROUGHOUT THE PERIOD AS WEDGE HOLDS ON ACROSS THE AREA. KEPT
SOME FZ RAIN IN FORECAST FOR A FEW HOURS EARLY WED MORNING AS
TEMPS REMAIN BELOW FREEZING ACROSS THE EXTREME WESTERN REACHES OF
LOCAL FORECAST AREA...WEST OF I95 FOR A FEW HOURS AROUND DAYBREAK.
SHORTWAVE WILL BE MOVING OFF TO THE EAST AT THIS TIME SO RAIN
CHANCES WILL DIMINISH THROUGH THE MORNING HOURS...LEAVING MORE IN
THE WAY OF LOW CLOUDS AND DRIZZLE FOR WED INTO WED NIGHT.
COLD AIR ADVECTION AND CLOUD COVER WILL KEEP TEMPS BELOW NORMAL
THROUGH MID WEEK. HIGH TEMPS WILL STRUGGLE TO MAKE IT OUT OF THE
40S WITH SLIGHTLY WARMER TEMPS CLOSER TO THE COAST. OVERNIGHT
TEMPS WILL BE DOWN IN THE 30S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 330 AM MONDAY...MID TO UPPER TROUGH WILL DIG DOWN FROM THE
GREAT LAKES AS IT MOVES EAST PHASING WITH SOUTHERN STREAM
SHORTWAVE. AS THIS SYSTEM MOVES EAST IT MAY ACT TO DEEPEN LOW
PRESSURE OVER THE SOUTHEAST. THE LATEST MODEL RUNS KEEP LOW
PRESSURE WELL SOUTH AND OFF SHORE. THEREFORE EXPECT BEST CHC OF
PCP TO REMAIN SOUTH OR OVER THE WATERS TO THE EAST...BUT EXPECT
LOW CLOUDS AND LOWER END PCP TO REMAIN OVER FORECAST AREA THROUGH
THURS.
ONCE THIS SYSTEM MOVES EAST THURS NIGHT INTO FRI...DEEP DRY N-NW
FLOW WILL DEVELOP. THIS WILL HELP TO SCOUR OUT ANY LOW CLOUDS AND
PCP PRESENT LEAVING DRIER SUNNIER WEATHER FOR FRI INTO SAT AS HIGH
PRESSURE MOVES OVER THE AREA FROM THE WEST. AIR MASS WILL MODIFY
BY THE WEEKEND AS COOLER NORTHERLY WINDS ON FRI LIGHTEN AND CAA
COMES TO END. COOLER NORTHERLY FLOW ON FRI WILL BE OFFSET BY
INCREASING SUNSHINE ALLOWING TEMPS TO MAKE IT INTO THE 50S MOST
PLACES. SATURDAY WILL BE THE SUNNIEST AND WARMEST DAY WHICH MAY
EXTEND INTO SUNDAY. MODELS ARE HINTING AT ANOTHER WEDGE POSSIBLY
SETTING UP SUN INTO MON BUT FOR NOW...WILL MAINTAIN A SUNNY...DRY
AND WARM FORECAST FOR SUN INTO MONDAY BUT CLOUDS MAY RETURN
ESPECIALLY BY MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...THE COASTAL FRONT REMAINS DRAPED ACROSS THE CWA
BETWEEN THE INLAND AND COASTAL TERMINALS. THE LOWEST PREDOMINATE
CONDITIONS...LIFR/IFR...ARE STILL WEST OF THE FRONT AT KFLO/KLBT.
AT THE COAST...EXPECT MAINLY MVFR CONDITIONS WITH TEMPO IFR AS
SHOWERS MOVE OVERHEAD. CONDITIONS WILL DETERIORATE TONIGHT AS THE
FRONT MOVES BACK OFFSHORE. LOOK FOR IFR/LIFR CIGS WITH PERIODS OF
DRIZZLE AND MVFR/IFR VSBYS TONIGHT ACROSS THE AREA. WINDS WILL
SHIFT TO THE NORTHWEST AND THEN NORTH OVERNIGHT INTO TUE
MORNING...BECOMING 10-15 KT DURING THE DAY. HAVE CARRIED IFR CIGS
THROUGH THE END OF THE PERIOD AT THE COAST...WHILE THE INLAND
TERMINALS MAY SEE A SLIGHT IMPROVEMENT IN CIGS BY LATE MORNING.
EXTENDED OUTLOOK...RAIN AND MVFR/IFR CONDITIONS WILL PREVAIL
POSSIBLY THROUGH WED AS A COOL WEDGE REMAINS LOCKED IN PLACE OVER
THE CAROLINAS. RAIN/MVFR ON THU. VFR FRI AND SAT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM MONDAY...SMALL CRAFT CONDITIONS REMAIN IN PLACE OVER
THE WATERS WITH SEAS RUNNING IN THE 4-7 FT RANGE. SEAS HAVE CLIMBED
ABOVE 5 FT AT BUOY 41108...AND FRYING PAN BUOY 41013 CONTINUES TO
REPORT 7 FT SEAS. SOUTH WINDS 15-20 KT WILL PERSIST THIS AFTERNOON...
BECOMING SOUTHWEST 10-15 KT THIS EVENING. EXPECT MORE SHOWERS AND
POSSIBLY AN ISOLATED TSTM OVER THE WATERS TODAY AS A WAVE OF LOW
PRESSURE RIDES UP THE COASTAL FRONT. HIGH PRESSURE WILL BUILD INTO
THE CAROLINAS LATE TONIGHT...SHIFTING THE WINDS AROUND TO THE
NORTHWEST AND ALLOWING SEAS TO DROP BELOW SCA CRITERIA...GENERALLY
3 TO 5 FT. AS HIGH PRESSURE BEGINS WEDGING DOWN THROUGH THE CAROLINAS
EARLY TUE...NORTH WINDS WILL STRENGTHEN TO AROUND 15 KT BY THE END
OF THE PERIOD.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM MONDAY...STRONG HIGH PRESSURE WILL BUILD DOWN FROM
THE NORTH AS COASTAL TROUGH SHIFTS OFF TO THE EAST. THIS WILL
LEAVE STRONGER N-NE WINDS THROUGH MUCH OF THE PERIOD. WINDS WILL
INCREASE FROM 10 TO 15 KT EARLY TUES UP TO 15 TO 25 KTS IN COOL
NORTHERLY SURGE THROUGH LATE TUES INTO WED ENHANCED BY SHORTWAVE
MOVING THROUGH. THEREFORE SEAS DOWN AROUND 3 TO 5 FT EARLY ON
TUES WILL JUMP BACK UP REACHING UP TO 5 TO 7 FT TUES NIGHT WITH
SCA CONDITIONS BACK IN THE FORECAST.
WINDS AND SEAS WILL DIMINISH THROUGH WED AS GRADIENT RELAXES
LEAVING NORTHERLY WINDS AROUND 10 TO 15 KTS AND SEAS DOWN BELOW
SCA THRESHOLDS BY LATE WED INTO THURS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 AM MONDAY...A SHORTWAVE MOVING IN FROM THE WEST WILL
DEEPEN LOW PRESSURE OVER THE WATERS OF THE SOUTHEAST. THIS SHOULD
HELP TO SHARPEN THE NORTHERLY FLOW INCREASING UP TO 15 TO 20 KTS
LATE THURS INTO FRI AS IT RIDES OFF TO THE EAST LEAVING A DEEP
COOL NORTHERLY FLOW OVER THE WATERS. SEAS AROUND 3 TO 5 FT MAY
SHOOT UP OVER SCA THRESHOLDS THURS NIGHT INTO FRI BEFORE RELAXING
AGAIN HEADING INTO THE WEEKEND AS GRADIENT RELAXES LEAVING NE
WINDS AROUND 10 TO 15 KTS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...RGZ
NEAR TERM...BJR
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR/BJR
MARINE...RGZ/BJR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1250 PM EST MON JAN 12 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL TRACK NORTHEAST OVER THE
EASTERN CAROLINAS AND MID ATLANTIC COAST THROUGH TONIGHT. A SERIES
OF UPPER LEVEL DISTURBANCES WILL MAINTAIN AN UNSETTLED WEATHER
PATTERN OVER THE CAROLINAS THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1040 AM MONDAY...
THE SHIELD OF RAIN THAT MOVED ACROSS CENTRAL NC DURING THIS
MORNING`S COMMUTE HAS MOVED EAST OF I-95...AS THE ASSOC LOW-MID
LEVEL MESO-VORT IS NOW LIFTING UP ACROSS NE NC ATTM (PER 88D). FOR
THE REST OF THIS MORNING...THE RAIN WILL BE MORE PATCHY IN NATURE
ACROSS THE TRIANGLE AND TRIAD REGIONS...WITH SYNOPTIC SCALE LIFT
WEAKENING IN THE WAKE OF THE AFOREMENTIONED DEPARTING VORT FEATURE.
MEANWHILE... WE`RE KEEPING OUR EYES ON THE ANOTHER LOW-LEVEL WAVE
AND AREA OF RAIN LIFTING NE ACROSS ERN GA AND SRN SC...BASICALLY
LIFTING NE UP ALONG THE STATIONARY SFC BOUNDARY THAT`S PRESENTLY
STRETCHING FROM COASTAL SC NWD ALONG THE NC HWY 17 CORRIDOR. CURRENT
HIRES NEAR-TERM GUIDANCE SUGGESTS THIS RAIN WILL MOVE UP INTO E-
CENTRAL AND ERN NC BY MID-DAY OR EARLY AFTERNOON...BASICALLY CATCHING
UP TO AND FILLING IN BEHIND THE RAIN THAT`S PRESENTLY FALLING EAST
OF I-95. AS SUCH...LOOK FOR A WET AFTERNOON ACROSS THE ERN HALF OF
OUR CWA...MAINLY EAST OF THE US-1 CORRIDOR...BUT ESP ALONG THE I-95
CORRIDOR AND EWD. WHILE SOME THUNDER CAN`T BE RULED OUT EARLY THIS
AFTERNOON ALONG THE SRN I-95 CORRIDOR WHEN THE RAIN SHIELD FIRST
MOVES UP IN THE SE NC...THE LATEST MESO-ANALYSIS AND HRRR SUGGEST
THE BEST LAPSE RATES AND INSTABILITY SHOULD REMAIN ALONG OR JUST OFF
THE COAST...WILL MONITOR. WHILE THE BULK OF THE RAIN...AND HEAVIEST
RAIN SHOULD REMAIN EAST OF US-1...LIGHT RAIN OR PATCHY DRIZZLE WILL
STILL BE POSSIBLE WEST OF US-1 THROUGH THE DAY. TEMPS WILL VARY
QUITE A BIT FROM NW TO SE: COOLEST NW (HIGHS ONLY REACHING THE LOW
40S)...AND WARMEST SE NEAR THE SFC WAVE AND BOUNDARY (MID-50S).
TONIGHT...A NEARLY SATURATED AIR MASS WILL REMAIN IN PLACE THOUGH
PRECIP WILL BE CONFINED TO MAINLY DRIZZLE AND SPOTS OF LIGHT RAIN AS
LIFT THROUGH THE COLUMN RATHER WEAK. A COLD FRONT ASSOCIATED WITH A
S/W CROSSING THE GREAT LAKES INTO SOUTHERN NEW ENGLAND WILL DRAG A
COLD FRONT TOWARD CENTRAL NC THIS EVENING AND INTO OUR NORTHERN
COUNTIES AFTER MIDNIGHT. CONVERGENCE ALONG THIS BOUNDARY MAY ENHANCE
THE SPOTTY LIGHT RAIN OR DRIZZLE COVERAGE OVERNIGHT. TEMPS THIS
EVENING WILL BE JUST A FEW DEGREES COOLER THAN AFTERNOON TEMPS. THE
PASSAGE OF THE COLD FRONT ACROSS THE NORTH SHOULD CAUSE TEMPS TO
COOL DURING THE PRE-DAWN HOURS. MIN TEMPS MID 30S ACROSS THE FAR
NORTH TO THE LOWER 40S FAR SOUTH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 320 AM MONDAY...
TUESDAY THROUGH WEDNESDAY: A REINFORCING SHOT OF COLD DRY AIR IN THE
LOW LEVELS WILL ARRIVE ON TUESDAY AS A STRONG ~1040 MB SURFACE
BUILDS SOUTHWARD FROM THE EASTERN GREAT LAKES AND NORTHEASTERN U.S.
OUR DAYTIME HIGH TEMPS WILL LIKELY OCCUR AROUND DAYBREAK FOR MOST IF
NOT ALL OF CENTRAL NC... WITH TEMPS FALLING THROUGHOUT THE DAY.
MEANWHILE A WEAK SOUTHERN STREAM S/W DISTURBANCE ALOFT WILL APPROACH
THE AREA FROM THE WEST-SOUTHWEST ON TUESDAY AND MOVE ACROSS THE
REGION ON TUESDAY NIGHT/WEDNESDAY MORNING. SOME LIGHT RAIN AND/OR
DRIZZLE MAY DEVELOP ACROSS THE AREA ON TUESDAY AFTERNOON IN RESPONSE
TO THE APPROACHING DISTURBANCE. THE BEST CHANCE OF PRECIP THOUGH
APPEARS TO BE LATE TUESDAY EVENING INTO EARLY WEDNESDAY MORNING...
WITH THE HIGHEST CHANCES ACROSS THE COASTAL PLAIN AND SOUTHERN
SANDHILLS.
GIVEN THE STRONG HIGH TO THE NORTH OF THE AREA AND LIGHT PRECIP...
WE MAY HAVE SOME PROBLEMS WITH LIGHT FREEZING RAIN AND/OR FREEZING
DRIZZLE ACROSS PORTIONS OF THE AREA FROM LATE TUESDAY THROUGH
WEDNESDAY MORNING (AS WE DO NOT HAVE SATURATION ALOFT ABOVE
-10C)... MAYBE EVEN INTO EARLY WEDNESDAY AFTERNOON. IN ADDITION...
PARTIAL THICKNESS VALUES DO INDICATE THE POSSIBILITY OF SOME SLEET
MIXING IN ACROSS THE FAR NORTHERN PIEDMONT EARLY WEDNESDAY MORNING.
THIS APPEARS POSSIBLE WITH THE LATEST GFS SOUNDING SHOWING THE
LOWEST 3-4 KFT OF THE ATMO BELOW FREEZING ALONG WITH A COLD NOES OF
AROUND -6 TO -7 DEGREES C EARLY WEDNESDAY MORNING ACROSS THE FAR
NORTHERN PIEDMONT. HOWEVER... WILL OMIT FROM THE FORECAST AT THIS
TIME AND FOCUS THE P-TYPE ON FREEZING RAIN/DRIZZLE ACROSS THESE
AREAS (MOST IMPACTFUL FOR THIS EVENT).
WHILE PRECIP AMOUNTS ARE EXPECTED TO BE LIGHT... GENERALLY LESS THAN
A TENTH OF AN INCH... TEMPS ARE EXPECTED TO FALL INTO THE UPPER 20S
TO AROUND 30 ACROSS THE PIEDMONT AND PORTIONS OF THE NORTHERN AND
CENTRAL COASTAL PLAIN ON WEDNESDAY MORNING. THIS WILL LIKELY SET THE
STAGE FOR SOME LIGHT ICE ACCRUAL ACROSS THE AFOREMENTIONED AREA.
DESPITE THE LOW PRECIP AMOUNTS... ONLY A FEW HUNDREDTHS OF ICE
ACCRUAL COULD CAUSE SOME SIGNIFICANT TRAVEL PROBLEMS FOR WEDNESDAY
MORNING... DESPITE THE LOW PRECIP TOTALS... ESPECIALLY ON ELEVATED
SURFACES SUCH AS BRIDGES AND OVERPASSES. HOWEVER... ALL WILL HINGE
ON THE PRECIP... AS WE MAY NOT SEE MUCH... IF ANYTHING WEST OF LINE
FROM ASHEBORO TO BURLINGTON. THUS... CONFIDENCE IS INCREASING THAT
WE MAY NEED A WINTER WX ADVISORY OVER PORTIONS OF THE PIEDMONT (IF
NOT ALL) AND NORTHERN AND CENTRAL COASTAL PLAIN FOR LATE TUESDAY
EVENING INTO WEDNESDAY MORNING... THOUGH HOW FAR WEST TO TAKE AN
ADVISORY IS STILL VERY UP IN THE AIR. STAY TUNED FOR LATER FORECASTS.
AS MENTIONED ABOVE HIGHS FOR THE DAYLIGHT HOURS ON TUESDAY WILL
OCCUR EARLY IN THE DAY... LIKELY NEAR DAYBREAK. THUS... WILL GO WITH
HIGH TEMPS RANGING FROM THE MID 30S NORTH TO THE MID 40S SOUTH...
AND LIKELY FALLING THROUGH THE DAY. LOWS WEDNESDAY MORNING ARE
EXPECTED TO RANGE FROM THE UPPER 20S IN THE HEART OF THE COLD AIR
DAMMING WEDGE TO THE LOWER 30S SOUTH AND EAST. HIGHS ON WEDNESDAY
ARE EXPECTED TO BE IN THE MID TO UPPER 30S... WITH LOCATIONS ACROSS
THE NORTHEAST PIEDMONT LINGERING BELOW FREEZING THE LONGEST GIVEN
THE PRECIP SHOULD END IN AN WEST TO EAST FASHION ON WEDNESDAY.
HOWEVER... WE SHOULD REMAIN LOCKED INTO THE CAD AIRMASS.
WEDNESDAY NIGHT: BEST MOISTURE AND LIFT IS EXPECTED TO PUSH JUST TO
THE EAST OF THE AREA BY WEDNESDAY NIGHT... WITH MAYBE SOME LINGERING
LIGHT RAIN AND OR DRIZZLE ACROSS THE COASTAL PLAIN. THE MAIN SURFACE
HIGH TO THE NORTH SHOULD BEGIN TO SHIFT EASTWARD. THUS... WILL KEEP
ANY MENTION OF PRECIP ACROSS THE COASTAL PLAIN AS A COLD RAIN.
EXPECT LOWS WILL RANGE FROM 30/LOWER 30S NORTHWEST TO THE MID 30S SE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...
A POSITIVE TILT TROUGH WILL APPROACH CENTRAL NC FROM THE WEST THU
AND EXIT THE REGION BY EARLY FRIDAY. MEDIUM RANGE GUIDANCE STILL
OFFER VARYING SOLUTIONS REGARDING THE PRECIP SHIELD ASSOCIATED WITH
THIS SYSTEM WITH THE GFS SUPPRESSED TO THE SOUTH OF OUR REGION AND
ECMWF DEPICTING THE NORTHERN EDGE OF THE PRECIP OVER THE SOUTH AND
EAST SECTIONS OF OUR FORECAST AREA. THE MORE NORTHERN EXTENT OF THE
ECMWF PRECIP LIKELY DUE TO THE TROUGH BEING SLIGHTLY MORE AMPLIFIED
COMPARED TO THE GFS. FOR NOW...WILL MAINTAIN CHANCE POPS ACROSS THE
SOUTH AND EAST AND SLIGHT CHANCE POPS ACROSS THE NW. EXTENSIVE CLOUD
COVER AND COOL NLY LOW LEVEL FLOW WILL KEEP HIGH TEMPS SEVERAL
DEGREES BELOW NORMAL. HIGHS THU MID-UPPER 40S.
A S/W RIDGE WILL BUILD INTO OUR REGION BEHIND THE EXITING TROUGH
FRIDAY AND CROSS THE REGION SATURDAY. THIS WEATHER SYSTEM WILL
INITIATE A DRY WEATHER REGIME WITH MODERATING TEMPERATURES. BY
SATURDAY...EXPECT HIGH TEMPS CLOSER TO NORMAL FOR MID JANUARY WITH
HIGHS RANGING FROM UPPER 40S TO AROUND 50 NORTH TO THE LOWER 50S
SOUTH. THE WARMING TREND CONTINUES INTO SUNDAY AS WLY FLOW
DOMINATES. AFTERNOON TEMPS HAVE THE POTENTIAL TO REACH WELL INTO THE
50S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1250 PM MONDAY...
PRIMARY AVIATION CONCERNS NEXT 24 HRS: CONTINUED IFR/LIFR CONDITIONS
AT ALL SITES... AND LOW LEVEL WIND SHEAR AT RDU/RWI/FAY NEXT 5 HOURS.
IFR/LIFR AVIATION CONDITIONS WILL PERSIST AT ALL CENTRAL NC TAF
SITES THROUGH EARLY AFTERNOON TUESDAY. A DEEPLY MOIST AND UNSETTLED
PATTERN IS IN PLACE WITH DISTURBANCES PASSING ALOFT... KEEPING A
GOOD CHANCE OF LIGHT RAIN OR DRIZZLE INTO EARLY THIS EVENING... WITH
THE BEST RAIN COVERAGE AFFECTING RDU/RWI/FAY AS A LOW PRESSURE AREA
TRACKS TO THE NE OVER COASTAL NC. WIDESPREAD IFR/LIFR FOG WILL
REMAIN PREVALENT AT ALL SITES THROUGH THIS EVENING... WITH LIGHT AND
VARIABLE WINDS. A COLD FRONT NOW OVER THE OH VALLEY WILL PUSH
SOUTHEAST THROUGH NC LATE TONIGHT... MAINLY BETWEEN 05Z AND 09Z...
AND WITH ITS PASSAGE THE SURFACE WINDS WILL SHIFT AROUND TO NORTH
THEN NORTHEAST... SUSTAINED NEAR 7-12 KTS WITH SOME GUSTS POSSIBLE
LATE TONIGHT INTO TUE MORNING. PATCHY DRIZZLE IS EXPECTED JUST
BEHIND THE FRONT LATE TONIGHT THROUGH THE END OF THE TAF VALID
PERIOD... WITH CIGS LIKELY TO REMAIN IFR/LIFR.
LOOKING BEYOND 18Z TUE: POOR AVIATION CONDITIONS WILL DOMINATE
THROUGH AT LEAST WED... WITH VERY MOIST AIR HOLDING IN PLACE FROM
THE SURFACE UP THROUGH THE LOWEST 7-10 THOUSAND FT... YIELDING
MAINLY IFR/LIFR CIGS. ANY PRECIP SHOULD BE VERY LIGHT THROUGH TUE
AFTERNOON... THEN A PASSING DISTURBANCE MAY BRING A BETTER CHANCE OF
SUB-VFR VSBYS IN RAIN AT FAY/RWI TUE NIGHT/WED MORNING. FAY/RWI MAY
SEE ANOTHER RAIN CHANCE EARLY THU WITH ANOTHER PASSING DISTURBANCE.
IMPROVEMENT TO VFR IS EXPECTED THU NIGHT AS A MID LEVEL TROUGH MOVES
OVERHEAD AND TO OUR EAST... THEN VFR CONDITIONS SHOULD DOMINATE
FRI/SAT AS HIGH PRESSURE NOSES IN FROM THE SW. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...NP/WSS
SHORT TERM...BSD
LONG TERM...WSS
AVIATION...HARTFIELD
Area Forecast Discussion
National Weather Service Spokane WA
236 PM PST MON JAN 12 2015
.SYNOPSIS...
High pressure will build over the Inland Northwest tonight and
linger through Wednesday. This will result in dry conditions with
sun in the mountains...and fog and low clouds in the valleys. Another
wet and relatively mild weather pattern is projected to return by
Thursday night and Friday, with mountain snow and valley rain or
snow.
&&
.DISCUSSION...
Tonight through Tuesday night...A weak shortwave trough will
continue to drop southeast of the forecast area tonight. Some very
light precipitation will linger over the southeast zones in
favorable upslope flow. The main forecast concern will be the
return of widespread fog and low stratus to the lower elevations
overnight as a ridge of high pressure replaces the exiting trough.
We may see the fog lift into low stratus for some locations
Tuesday but most valleys will probably say goodbye to sunshine for
a while. There may be a reprieve for the northeast valleys Tuesday
afternoon in light northeast downsloping winds. The Palouse and
Lewis-Clark valley may also break out of the fog/stratus if
easterly gradient winds are strong enough Tuesday. There could
also be a brief snow shower over extreme northeast WA and the
northern panhandle of Idaho Tuesday as a very weak shortwave
impulse rolls through the ridge. This may act to clear some of the
fog briefly but it is likely to return Tuesday night. Temperatures
for the fog clogged valleys will have very small diurnal ranges
while the mountains manage to warm above the strengthening
inversions. /Kelch
Wednesday and Wednesday night...A strong surface inversion will
remain in place as high pressure lingers over the region...then
shifts to the east as the pattern begins to change. This will
result in a continuation of low clouds and fog across the region
and temperatures on the cool side. On the flip side the mountains
will remain sunny and on the warm side of average.
Thursday through Friday night...The pattern is expected to become
more active beginning Thursday and lasting into the weekend.
Models are in decent agreement bringing a warm front through the
region Thursday night. Southwest flow will tap into deeper Pacific
moisture and result in high confidence that just about all
locations will get measurable precipitation. The heaviest
precipitation in this kind of pattern is usually along the crest
of the Cascades...the northeast and Panhandle mountains...and
this case is no different. Snow type will begin as rain south of
I-90 and snow north...as the warm air advects into the region
Thursday night and Friday snow levels will increase with snow
north of Highway 2 and rain south of Highway 2. We have put in a
few hours worth of freezing precipitation for the Wenatchee valley
up to Leavenworth...along the Columbia River and east in the the
deep basin. Model guidance is showing the possibility early Friday
evening. However the cold air that is in place in these areas is
not very deep and should mix out with the southerly winds and warm
air advection. As such confidence in any freezing precipitation is
low, but worth mentioning for the time being.
Snow amounts will range from a trace to a few tenths in the lower
elevations...To 2-3 inches for the mountain valleys...4-8 inches
for the northeast and Panhandle mountains and possibly up to a
foot near the Cascade crest. A cold front will follow Friday
afternoon and result in a drying trend for the west...while up-
sloping flow keeps higher pops in the eastern mountains.
Saturday and Saturday night...This is where the models begin to
diverge by quite a bit with models about 6-12 hours slower. With
no ridging in place the thinking is that faster would be better.
The consensus leans in this direction and that`s the way this
forecast leans. As such we expect another period of moderate to
heavy precipitation. Snow levels will again be on the increase
with rain below 3000feet and snow above 3000 feet. There will also
be a decent chance of snow for the northern valleys, but these
valleys will likely turn over to rain by Saturday evening. Tobin
Sunday and Monday...Not much sign that the wet weather will
come to an end...as swift southwest flow will likely remain
entrenched over the Inland NW. Models in better agreement than
yesterday for this period as all now are showing a consolidated
flow regime vs. the split flow advertised by the GFS yesterday.
Given the fairly robust westerly winds through the middle
atmosphere we`re fairly confident there will be a well-defined
rain shadow...with low chances for precipitation over the western
Columbia Basin and significantly higher precipitation chances
along the Cascade Crest and over the Idaho Panhandle. There are
hints that the Sunday system could be accompanied by another
atmospheric river...so a significant amount of precipitation could
occur...especially where orographic ascent is maximized (Cascade
Crest and ID Panhandle). Looks like snow levels will be high
enough that any significant snow should be reserved for mountain
locations (3k feet or higher near Canadian border and to 4-5k feet
along and south of I90). The treat of precipitation will begin to
wane as a compact shortwave trough pushes a cold front over the
Cascades and into southern Alberta. The question is when will this
happen. Both the GFS and Canadian suggest this will happen during
the afternoon...while the ECMWF waits until the evening or
overnight hours. The passage of the front will likely be
accompanied by breezy conditions as well with 850 mb winds peaking
around 40 knots. By Sunday night and Monday...the chances for
precipitation will begin to shrink and turn more showery as drier
air moves in behind the front. Despite the drying...atmospheric
lapse rates plummet...especially over northeast Washington and
north Idaho as 500 mb temps plunge below -30C. The ECMWF keeps
this colder air well to the west. fx
&&
.AVIATION...
18Z TAFS: A transition period between an active weather system
impacting the southeastern TAF sites with occasional light rain
and snow will transition back to a high pressure dominated low
level inversion scenario over the next 24 hours. The KPUW TAf site
will be especially troublesome with LIFR conditions. The weak
westerly gradient with a very moist low level air mass is
conducive to long lasting LIFR conditions. HRRR model and GFS
moisture fields suggest some improvement this afternoon but this
is a low confidence forecast until the gradient turns decidedly
easterly...not expected in the next 24 hours. KGEG TAF should
remain VFR through the morning benefiting from dry air advecting
in from the northeast but will probably deteriorate to IFR or LIFR
conditions late this afternoon and more likely tonight as high
pressure becomes established. KMWH will probably remain VFR until
tonight when IFR conditions will return. KEAT visibility has
improved and ceilings has lifted to IFR and should continue to
improve this afternoon before deteriorating again tonight. Most
of the Columbia Basin will be cloaked with IFR or low MVFR stratus
by 12Z Tuesday. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 25 33 24 34 26 34 / 10 10 10 10 0 10
Coeur d`Alene 26 34 22 35 26 36 / 10 10 10 10 0 10
Pullman 29 35 25 36 29 39 / 10 10 0 0 0 10
Lewiston 31 38 28 41 32 43 / 10 10 0 0 0 10
Colville 20 31 20 32 24 30 / 10 10 10 10 0 20
Sandpoint 21 33 21 32 25 35 / 10 10 10 10 0 10
Kellogg 26 34 23 35 27 35 / 20 10 0 0 0 10
Moses Lake 27 34 26 36 27 36 / 10 0 0 0 0 10
Wenatchee 28 34 27 35 29 35 / 10 10 10 10 0 20
Omak 21 31 22 32 27 31 / 10 10 10 10 10 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS PORTLAND OR
230 PM PST MON JAN 12 2015
.SYNOPSIS...AN UPPER RIDGE OF HIGH PRES WILL BUILD IN TONIGHT AND
TUESDAY FOR DRY BUT STABLE CONDITIONS THAT WILL LAST THROUGH WED.
THE WEATHER PATTERN WILL BECOME MORE ACTIVE LATE IN THE WEEK AND
THIS WEEKEND AS A SERIES OF INCREASINGLY WET SYSTEMS BEGINS TO MOVE
IN OFF THE PACIFIC.
&&
.SHORT TERM...RADAR AND SURFACE OBSERVATIONS INDICATED MOST OF THE
SHOWERS HAD TAPERED OFF BY EARLY THIS AFTERNOON...THE LAST FEW
REMAINING IN THE OREGON CASCADES AND IN THE FAR S. EXPECT SHOWERS TO
COME TO AN END EARLY EVENING AS LOW LEVEL FLOW TRANSITIONS OVER TO
OFFSHORE. MODELS THEN REMAIN CONSISTENT IN SHOWING THE UPPER
RIDGE...SEEN NEAR 135W THIS AFTERNOON...SHIFTING INLAND OVER THE
PACIFIC NW FOR TUE AND WED. SURFACE HIGH SHIFTS E OF THE CASCADES
FOR OFFSHORE FLOW IN THAT TIME FRAME...WITH THE PEAK OFFSHORE
GRADIENTS THROUGH THE GORGE OCCURRING AROUND WED MORNING IN THE NAM.
WITH THE RIDGE ALOFT SHIFTING INLAND EXPECT ANOTHER STRONG LOW LEVEL
SUBSIDENCE INVERSION TO SET UP FOR TUE THROUGH WED. THIS INFERS
WIDESPREAD LOW CLOUDS AND FOG IN THE INLAND VALLEYS...EXCEPT FOR
AREAS IMMEDIATELY DOWNSTREAM OF THE GORGE.
MODELS ALSO REMAIN IN REASONABLY GOOD AGREEMENT SHOWING A SHORTWAVE
LIFTING UP INTO THE REGION AND INTO THE RIDGE WED NIGHT. FIRST
SYSTEMS INTO A RIDGE GENERALLY TEND TO BE ON THE WEAK SIDE...SO WILL
KEEP CHANCE FOR RAIN CONFINED TO CHANCE CATEGORY OR LESS WED NIGHT.
BY THU TREND IN THE MODELS IS FOR THE UPER RIDGE TO FLATTEN AND
SHIFT INLAND. THIS ALLOW A MORE PROGRESSIVE LOOKING PATTERN TO SET
UP...WITH THE NEXT POTENTIALLY WETTER SYSTEM APPROACHING THU AND THU
NIGHT. AS A RESULT OF GOOD AGREEMENT IN MODELS...WILL BUMP UP POPS S
LITTLE FOR THU.
.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY. FORECAST MODELS REMAIN
IN FAIR AGREEMENT WITH BRINGING A STRONGER FRONTAL SYSTEM ACROSS THE
FORECAST AREA LATE THURSDAY NIGHT INTO FRIDAY. THIS SYSTEM LOOKS TO
BRING SIGNIFICANT RAINFALL TO THE REGION WITH A TAP INTO SOME
SUBTROPICAL MOISTURE THAT WILL TAKE AIM AT THE PACIFIC NORTHWEST.
SNOW LEVELS WILL BE STARTING OFF QUITE HIGH SO WITH ONLY MODEST COLD
AIR ENTERING THE REGION BEFORE THE PRECIPITATION TAPERS
OFF...SUSPECT THAT ACCUMULATING SNOW WILL BE LARGELY LIMITED TO
LOCATIONS WELL ABOVE THE CASCADE PASSES...ABOUT 5500 FT OR SO. A
SERIES OF UPPER LEVEL WAVES MAY BRING CONTINUED RAIN THROUGH MUCH OF
THE WEEKEND...WITH THE POTENTIAL FOR RAINFALL TOTALS ON THE ORDER OF
SEVERAL INCHES FOR THE THURSDAY NIGHT THROUGH SUNDAY NIGHT PERIOD.
THERE MAY BE A FEW BRIEF BREAKS IN THE RAIN OVER THE WEEKEND BETWEEN
EACH IMPULSE ROTATING THROUGH...BUT GIVEN SLIGHT MODEL DIFFERENCES
DID NOT ATTEMPT TO TIME THESE AND INSTEAD MAINTAINED CHANCE TO
LIKELY POPS THROUGH THE WEEKEND. THE FRONTAL SYSTEM WILL NOT BE
PARTICULARLY COOL...AND EXPECT BOTH MAX AND MIN TEMPERATURES TO RUN
SEVERAL DEGREES ABOVE SEASONAL NORMALS THROUGH THE EXTENDED PERIOD.
CULLEN
&&
.AVIATION...PORTIONS OF THE CENTRAL AND SOUTHERN INTERIOR VALLEY
HAVE BEEN SLOW TO CLEAR THIS AFTERNOON. AS SUCH...EXPECT TO SEE A
MIXTURE OF IFR TO VFR CONDITIONS THROUGH TONIGHT...WITH POCKETS OF
LIFR CIGS. COASTAL AREAS AND AREAS NORTH OF KSLE CAN EXPECT TO SEE
MAINLY VFR CONDITIONS THROUGH TONIGHT...WITH POCKETS OF MVFR CIGS.
ABUNDANT LOW-LEVEL MOISTURE AND LIGHT WINDS WILL LEAD TO THE
DEVELOPMENT OF FOG AND LOW LEVEL STRATUS LATE TONIGHT. EXPECT
CONDITIONS IN THE INTERIOR VALLEY TO DETERIORATE TOWARDS IFR TO
LIFR AROUND MIDNIGHT AND CONTINUE THROUGH AT LEAST LATE TUE
MORNING. HOWEVER...DECENT OFFSHORE FLOW WILL LIKELY KEEP MVFR TO
VFR CONDITION ALONG THE COAST THROUGH TUE MORNING. CONDITIONS
ACROSS THE REGION LOOK TO GRADUALLY IMPROVE TOWARDS VFR BY TUE
AFTERNOON.
KPDX AND APPROACHES...VFR CONDITIONS CONTINUE THROUGH THIS
EVENING. HOWEVER...ABUNDANT LOW-LEVEL MOISTURE AND LIGHT WINDS
WILL CREATE CONDITIONS PRIME FOR FOG DEVELOPMENT LATE TONIGHT
WITH IFR CIGS AND VIS POSSIBLE BY MIDNIGHT. /64
&&
.MARINE...HIGH PRES WILL CONTINUE TO BUILD OVER THE WATERS TODAY
AND REMAIN IN PLACE THROUGH WED. OFFSHORE FLOW WILL DEVELOP ACROSS
THE REGION BY TUE MORNING. WINDS WILL VEER TO THE SE TO S ON WED
AS A WEAK WEATHER SYSTEM MOVES ACROSS THE WATERS BRINGING WITH IT
THE POTENTIAL FOR SMALL CRAFT ADVISORY WINDS BY LATE WED.
HOWEVER...SEAS LOOK TO REMAIN BELOW 10 FT.
A MUCH STRONGER FRONTAL SYSTEM LOOKS TO MOVE ACROSS THE WATERS ON
THU...WITH GALE FORCE GUSTS OVER THE OUTER WATERS POSSIBLE BY THU
AFTERNOON. SEAS WILL GRADUALLY CLIMB TO THE LOW TEENS BY LATE THU.
ANOTHER SYSTEM LOOKS TO MOVE ACROSS THE WATERS LATE FRI...FOLLOWED
BY A WEAKER SYSTEM ON SUN. HOWEVER...CONFIDENCE CONTINUE TO REMAIN
LOW AT THE MOMENT DUE TO LARGE MODEL DIFFERENCES. /64
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
Area Forecast Discussion
National Weather Service Spokane WA
1005 AM PST MON JAN 12 2015
.SYNOPSIS...
A weak system will move by the Pacific Northwest tonight into
Monday morning, with a threat of light snow. However clouds will
be the more dominant weather condition. High pressure returns for
the new work week, with dry but mostly cloudy conditions. Another
wet and relatively mild weather pattern is projected to return by
next weekend, with mountain snow and valley rain or snow.
&&
.DISCUSSION...
Minor update this morning to add some low end PoPs to the upper
Columbia basin southeast into the Palouse for a weak impulse
slowly sliding southeast across the area. Very light returns seen
on radar for this feature but enough for some flurries. Fog
coverage was also extended for a few more hours in portions of
the Palouse as webcams show it is not budging in the Pullman and
Uniontown areas. /Kelch
&&
.AVIATION...
8Z TAFS: A transition period between an active weather system
impacting the southeastern TAF sites with occasional light rain
and snow will transition back to a high pressure dominated low
level inversion scenario over the next 24 hours. The KPUW TAf site
will be especially troublesome with LIFR conditions. The weak
westerly gradient with a very moist low level air mass is
conducive to long lasting LIFR conditions. HRRR model and GFS
moisture fields suggest some improvement this afternoon but this
is a low confidence forecast until the gradient turns decidedly
easterly...not expected in the next 24 hours. KGEG TAF should
remain VFR through the morning benefiting from dry air advecting
in from the northeast but will probably deteriorate to IFR or LIFR
conditions late this afternoon and more likely tonight as high
pressure becomes established. KMWH will probably remain VFR until
tonight when IFR conditions will return. KEAT visibility has
improved and ceilings has lifted to IFR and should continue to
improve this afternoon before deteriorating again tonight. Most
of the Columbia Basin will be cloaked with IFR or low MVFR stratus
by 12Z Tuesday. /EK
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 32 26 33 26 33 27 / 20 10 10 10 10 0
Coeur d`Alene 34 27 35 24 34 27 / 20 10 10 10 10 0
Pullman 34 30 37 27 37 30 / 40 10 10 0 0 0
Lewiston 40 32 40 30 39 33 / 40 10 10 0 0 0
Colville 30 21 30 23 31 25 / 10 10 10 10 10 0
Sandpoint 33 25 34 23 33 26 / 10 10 10 10 10 0
Kellogg 34 27 35 24 34 28 / 20 20 10 0 0 0
Moses Lake 37 27 34 29 34 28 / 10 10 0 0 0 0
Wenatchee 38 29 34 30 34 30 / 10 10 10 10 10 0
Omak 35 24 31 26 31 28 / 10 10 10 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$