Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/14/15
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
600 PM MST TUE JAN 13 2015
.UPDATE...
UPDATED AVIATION SECTION.
&&
.SYNOPSIS...
AN EXITING WEATHER SYSTEM WILL AFFECT EASTERN ARIZONA THROUGH EARLY
WEDNESDAY...KEEPING CHANCES FOR SHOWERS ACROSS HIGHER TERRAIN AREAS
EAST OF PHOENIX. BEHIND THIS SYSTEM...MUCH DRIER AIR AND
LOCALLY BREEZY CONDITIONS WILL FILTER SOUTH INTO THE AREA. HOWEVER
AFTER THIS SYSTEM PASSES...HIGH PRESSURE WILL RETURN WITH SLOWLY
INCREASING TEMPERATURES THROUGH THE WEEKEND.
&&
.DISCUSSION...
A FAIRLY IMPRESSIVE RAIN BAND WITH EMBEDDED MODERATE TO EVEN HEAVY
SHOWERS MOVED OUT OF CENTRAL ARIZONA THIS MORNING INTO THE PHOENIX
AREA LATE IN THE MORNING...AND NOW IS PUSHING INTO THE MOUNTAINS TO
THE EAST. RAINFALL AMOUNTS WERE GENERALLY AROUND A TENTH OF AN
INCH...BUT THERE WERE A FEW LOCALIZED AMOUNTS OF A QUARTER INCH OR
MORE. THE UPPER TROUGH RESPONSIBLE FOR THIS RAIN IS NOW CENTERED
OVER NORTHWEST ARIZONA...BUT THE MAJORITY OF THE VERTICAL ASCENT IS
NOW SITUATED OVER SOUTHEAST ARIZONA NEAR A 120 KT UPPER JET STREAK.
DRY AIR ALOFT CAN BE SEEN ON WATER VAPOR IMAGERY TO THE SOUTH OF THE
UPPER LOW CENTER OVER SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA.
THIS DRY AIR ALONG WITH GRADUALLY INCREASING SUBSIDENT FLOW ALOFT
SHOULD KEEP OUR RAIN CHANCES FOR THE REST OF TODAY MAINLY LIMITED TO
HIGHER TERRAIN AREAS EAST OF PHOENIX. HOWEVER...VISIBLE IMAGERY DOES
SHOW A GOOD AMOUNT OF SUNSHINE TO THE WEST OF PHOENIX AND SOME CU
DEVELOPMENT OVER THE PAST HOUR. MAY SEE A FEW SHOWERS FORM IN THESE
SUNNY AREAS THROUGH THE REST OF THE AFTERNOON...BUT WITH VERY
LIMITED INSTABILITY...ANY DEVELOPMENT SHOULD REMAIN ISOLATED.
THE LATEST HI-RES HRRR AND WRF4KM RUNS SHOWS THE BULK OF THE RAIN
ENDING BY EARLY EVENING. THERE WILL BE A LINGERING CHANCE OF SOME
SHOWERS ACROSS EASTERN ARIZONA DURING THE OVERNIGHT HOURS AS THE
MAIN VORT MAX AND PVA ANOMALY CURRENTLY OVER NORTHWEST ARIZONA
SLIDES SOUTHEASTWARD. NOT WORRIED ABOUT THE CHANCES FOR MUCH SNOW
TONIGHT AS THE SYSTEM IS NOT UNUSUALLY COLD OR DEEP AND
HEIGHTS/THICKNESSES ALOFT INDICATE FREEZING LEVEL REMAINING AOA 7K
FT. THEREFORE...SNOW LEVELS SHOULD REMAIN WELL ABOVE POPULATION
CENTERS/TRANSPORTATION CORRIDORS WITH ONLY A DUSTING ON THE PEAKS OF
SRN GILA COUNTY LATER TONIGHT. AS THE LOW CENTER AND COLD CORE
SHIFTS OVER EAST-CENTRAL ARIZONA DURING THE DAYTIME HOURS
WEDNESDAY...WE SHOULD SEE SOME DIURNALLY FORCED SCT RAIN/SNOW SHOWER
REDEVELOPMENT WITHIN THE COLD CORE...BUT PRIMARILY LIMITED TO THE
WHITE MOUNTAINS OF ERN ARIZONA.
OPERATIONAL AND ENSEMBLE MEMBERS ARE IN VERY GOOD AGREEMENT THAT
STRONGER ZONAL PACIFIC JET ENERGY WILL FORCE A SIGNIFICANT
DOWNSTREAM PATTERN SHIFT OVER THE WESTERN HEMISPHERE DURING THE
LATTER HALF OF THIS WEEK INTO NEXT WEEK...UNLOCKING THE PREVAILING
BLOCKED FLOW INTO A MORE PROGRESSIVE QUASI-ZONAL PATTERN. SHORTWAVE
FEATURES OVER THE CONUS WILL BE EXCLUSIVELY LOW AMPLITUDE AND
RELEGATED TO THE NORTHERN STREAM WITH FLAT RIDGING PREDOMINATING THE
SWRN REGION. AS A RESULT...ENSEMBLE GUIDANCE EXHIBITS VERY LOW
FORECAST SPREAD WITH H5 HEIGHTS OSCILLATING AROUND A 580DM RANGE AND
H8 TEMPERATURES NEAR +10C. BASED ON HISTORICAL BIASES DURING SIMILAR
PATTERN EVOLUTION...HAVE HEDGED TOWARDS THE WARMEST GUIDANCE
PACKAGES YIELDING FORECAST HIGHS AT LEAST 5F ABOVE AVERAGE. EVEN
THIS APPROACH MAY BE CONSERVATIVE GIVEN A DRY ENVIRONMENT AND
POTENTIALLY SEVERAL DAYS OF FULL INSOLATION.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
AS OF 6 PM...01Z...SHOWER ACTIVITY MOSTLY CONFINED TO EASTERN THIRD
OF ARIZONA WITH SOME ISOLATED MODEST CONVECTION OVER SOUTHWEST
MARICOPA COUNTY AND SOUTHERN YAVAPAI COUNTY. DECREASING CLOUDINESS
OVER PHOENIX AREA WILL CONTINUE THIS EVENING...EXCEPT FOR FAR
NORTHERN PORTIONS OF THE METRO AS CLOUDINESS ORIGINATING OVER HIGHER
TERRAIN DRIFT SOUTHEASTWARD. THIS MAY CONTINUE WELL THROUGH THE
EVENING AS ANOTHER EMBEDDED DISTURBANCE ASSOCIATED WITH THE UPPER
LOW MOVES THROUGH. MEANWHILE...EXPECT ISOLATED LOWER DESERT SHOWERS
SOUTH OF PHOENIX METRO TO DIMINISH BY ABOUT 02Z. ANTICIPATE SOME
SCATTERED MID CLOUDS TO LINGER THROUGH THE EVENING. SOME HAZE/MIST
MAY DEVELOP IN SPOTS AFTER 09Z LOWERING VIS BELOW 10SM...POSSIBLY
DOWN TO 5SM. HOWEVER WITH THE UPPER LOW SLOWLY MOVING THROUGH
ANTICIPATE JUST ENOUGH INSTABILITY TO PRECLUDE DENSE FOG
DEVELOPMENT. OTHERWISE EXPECT SURFACE WINDS TO REMAIN LIGHT WITH
LOWER LEVELS TRENDING TOWARD EASTERLY DIRECTIONS AFTER 06Z.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
ANTICIPATE NORTHERLY SURFACE WINDS CONTINUING TO WEAKEN EARLY THIS
EVENING TRENDING TOWARD FAVORED NOCTURNAL PATTERNS BY 06Z IF NOT
SOONER. ANTICIPATE MODERATE NORTHERLY SURFACE WINDS CONTINUING IN
THE LOWER LEVELS ABOVE THE INVERSION OVERNIGHT WITH RESUMPTION OF
NORTHERLY SURFACE WINDS BY 18Z WEDNESDAY...GUSTS REMAINING BELOW 15
KTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
UPPER LEVEL RIDGING WILL TAKE SHAPE ACROSS THE REGION BY FRIDAY AND
REMAIN LARGELY IN PLACE THROUGH EARLY NEXT WEEK. THIS WILL RESULT IN
INCREASED TEMPERATURES WITH DAILY HIGH TEMPERATURES SEVERAL DEGREES
OR MORE ABOVE SEASONAL NORMALS EACH DAY. DESPITE THE PRESENCE OF
HIGH PRESSURE...HUMIDITIES WILL STAY A BIT ELEVATED EACH DAY WITH
MINIMUM RH VALUES MOSTLY BETWEEN 15 AND 25 PERCENT ACROSS THE
DESERTS. WINDS THROUGH THE PERIOD WILL BE LIGHT AND GENERALLY
DIURNAL IN NATURE.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...KUHLMAN/MO
AVIATION...AJ
FIRE WEATHER...CB
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
NWS GRAND JUNCTION CO
616 PM MST TUE JAN 13 2015
.UPDATE...
ISSUED AT 616 PM MST TUE JAN 13 2015
ALLOWED ALL WARNINGS AND ADVISORIES TO EXPIRE AT 6 PM LOCAL TIME.
LIGHT ACCUMULATIONS MAY CONTINUE THIS EVENING OVER THE SWRN SAN
JUAN MOUNTAINS...BUT THE BRUNT OF THE HEAVY SNOW HAS ENDED.
THE OTHER FORECAST QUESTION THAT NEEDS TO BE MONITORED IS FOG
FORMATION. MAY BE SUFFICIENT CLOUD COVER OR WIND CIRCULATION TO
PREVENT WIDESPREAD LOW LYING FOG...BUT THE TREND WILL BE FOR
CLEARING SKIES OVERNIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 253 PM MST TUE JAN 13 2015
UPPER LEVEL LOW HAS JUST DROPPED BELOW THE UTAH STATE LINE INTO
ARIZONA AS MOIST SWLY FLOW CONTINUES TO PUMP MOISTURE INTO THE
REGION. ALONG AND JUST N OF INTERSTATE 70...FLOW HAS TURNED
EASTERLY WITH RADAR SHOWING RETURNS THAT ARE MORE CONVECTIVE IN
NATURE. ALL MODELS CONTINUE TO HIGHLIGHT A RATHER BROAD AREA OF
DEFORMATION THAT APPEARS TO BE PANNING OUT WITH SOME DISTINCT
BANDS OF PRECIP HAVING SET UP OVER THE REGION. UNDER THESE
BANDS...EXPECT PRECIP TO PICK UP SOME BUT COVERAGE LOOKS TO BE
SOMEWHAT LIMITED SO DO NOT ANTICIPATE MUCH OF AN INCREASE TO RAIN
AND SNOW TOTALS. SPEAKING OF...MANY REPORTS OF DECENT SNOWFALL
WITH MONTEZUMA COUNTY REPORTING 6 TO 8 INCHES...LA PLATA COUNTY
CAME IN WITH 6 TO 10 INCHES AND ARCHULETA COUNTY REPORTS 8 TO 12
INCHES IN SOME SPOTS. NAM12 CONTINUES TO SHOW RATHER WIDESPREAD
PRECIP FOR THE SAN JUANS AND AREAS SOUTH THROUGH TONIGHT BUT THIS
LOOKS WAY OVERDONE. HRRR IS MUCH MORE CONSERVATIVE AND ALSO SHIFTS
THE BEST PRECIP SOUTHWARD INTO NEW MEXICO. VISIBLE SATELLITE DOES
SHOW PLUME OF MOISTURE STEADILY DROPPING EAST AND SOUTH SO THINK
HRRR HAS THE BEST HANDLE ON CURRENT SITUATION. FOR THE REMAINDER
OF THE DAY THEN...A FEW MORE INCHES...1 TO 3...FOR THE MOUNTAINS
WITH VALLEYS POSSIBLY SEEING ANOTHER INCH OR TWO. CURRENT HIGHLIGHTS
CONTINUE THROUGH 6PM SO WILL KEEP THEM GOING.
FOR WEDNESDAY...HIGH PRESSURE BUILDS IN WITH LESS CLOUDS UP NORTH
AND MORE DOWN SOUTH WITH CONDITIONS IMPROVING THROUGH THE DAY. ONLY
BIG QUESTION MARK WILL BE FOG AND HOW THICK AND HOW WIDESPREAD IT
WILL BE AS AMPLE MOISTURE WILL REMAIN IN THE ATMOSPHERE DUE TO THE
EVAPORATING SNOWFALL ESPECIALLY SOUTH. TEMPS WILL STAY NEAR
NORMAL THROUGH THE PERIOD WITH A WARMUP TOWARDS THE END OF THE
WEEK.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 253 PM MST TUE JAN 13 2015
A PROGRESSIVE FLOW WILL BRING A SERIES OF RIDGES AND TROUGHS
ACROSS THE CONUS DURING THE LONG TERM PERIOD. FOR THE MOST
PART...OUR FORECAST AREA WILL BE SOUTH OF...OR ON THE SOUTHERN
EDGE AT BEST OF ANY WEATHER ASSOCIATED WITH ANY DISTURBANCE THAT
PASSES. ALSO TIMING WILL REMAIN DIFFICULT FOR THESE FAST MOVING
WAVES.
ON THU AT THE START OF THE PERIOD. THE AREA WILL BE UNDER A
FLATTENING RIDGE THAT WASHES OUT AS IT GETS PUSHED EAST THU NIGHT.
A SHORTWAVE TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST ON
FRIDAY...THEN WILL BRUSH OUR FORECAST AREA FRI NIGHT INTO SAT.
EXCEPT FOR THE LATEST/12Z ECMWF...THE MODELS HAVE INDICATED THAT
THIS WAVE WILL JUST BARELY BRUSH OUR NORTHEAST CORNER...WITH THE
FLOW MAINLY STAYING ZONAL. THE 12Z EC HOWEVER IS MORE AMPLIFIED
THAN EARLIER RUNS WHICH COULD MEAN A BETTER CHANCE OF SNOW...STILL
STAYING MAINLY OVER THE NORTH AND CENTRAL CO MOUNTAINS. WILL KEEP
THE GENERALLY DRY FORECAST FOR NOW BEFORE BUYING OFF ON THIS
STRENGTHENING TREND.
A RIDGE WILL BUILD BEHIND THIS WAVE ON SUN...THEN FLATTEN AGAIN
DURING THE EARLY PART OF THE WORK WEEK AS WAVES MOVES INTO WESTERN
NOAM. EXPECT TEMPERATURES TO RUN JUST A LITTLE ABOVE NORMAL FOR
THE MOST PART. THE MEX AND ECE GUIDANCE NUMBERS SHOW RATHER BIG
DIFFERENCES...WITH THE MEX PROBABLY TOO WARM AND ECE TOO COOL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 616 PM MST TUE JAN 13 2015
LOW CIGS WITH AREAS OF SNOW PERSIST OVER SW COLORADO THIS EVENING.
THESE CONDITIONS WILL IMPROVE TONIGHT AS SNOW COVERAGE CONTINUES
TO DECREASE. TAF SITES IN ERN UTAH AND NW COLORADO WILL BE AT VFR
TONIGHT.
LOCAL FOG MAY LIMIT VISIBILITY ALONG RIVER VALLEYS AND LOW LYING
AREAS LATE TONIGHT. CLOUD COVER OR WIND CIRCULATIONS MAY BE
SUFFICENT TO KEEP TAF SITES FREE FROM FOG...BUT THIS NEEDS TO BE
MONITORED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...PF
SHORT TERM...TGR
LONG TERM...EH
AVIATION...PF
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
900 PM EST TUE JAN 13 2015
.UPDATE (REST OF TONIGHT AND WEDNESDAY)...
02Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A RATHER BENIGN UPPER
LEVEL PATTERN ACROSS THE CONUS THIS EVENING. A WEAK SHORTWAVE IS
CURRENTLY RIDING THE MAINLY ZONAL FLOW TO THE NORTH OF FLORIDA...BUT
WILL HAVE LITTLE IMPACT ON OUR SENSIBLE WEATHER OTHER THAN TO HELP
PROPEL A WEAK FRONTAL SYSTEM SOUTH OF OUR AREA. WV IMAGERY SHOWS
PLENTY OF UPPER LEVEL SOUTHERN STREAM MOISTURE EXTENDING ACROSS THE
GULF OF MEXICO AND FLORIDA PENINSULA. THIS SOUTHERN STREAM ENERGY
WILL KEEP SCT-BKN BANDS OF HIGH LEVEL CIRRUS STREAMING OVER OUR
HEADS THROUGH THE DAY ON WEDNESDAY...AND IN FACT...SHOULD SEE THE
CIRRUS BECOME THICKER DURING WEDNESDAY AS THE JET STRENGTHENS TO OUR
WEST OVER THE NORTHERN GULF COAST.
AS MENTIONED ABOVE...WEAK FRONTAL BOUNDARY AT THE SURFACE WILL BE
PUSHING SOUTH OF THE REGION OVERNIGHT ALLOWING SOME SLIGHTLY DRIER
AIR TO FILTER DOWN FROM THE NORTH. OVERALL TEMPERATURES OVERNIGHT
WILL BE SEASONABLE WITH 50S NORTH OF TAMPA AND INLAND FROM THE I-75
CORRIDOR...AND LOWER 60S CLOSE TO THE COAST FROM PINELLAS COUNTY
SOUTHWARD.
CONDITIONS APPEAR FAVORABLE FOR THE DEVELOPMENT OF FAIRLY WIDESPREAD
LOWER CLOUDS AS THE NIGHT PROGRESSES...AND THERE IS GOOD AGREEMENT
AMONG THE DETERMINISTIC AND STATISTICAL GUIDANCE IN THIS.
SREF/NARRE/MAV GUIDANCE IS ALL POINTING HIGH POTENTIAL FOR CIGS TO
DROP BELOW 1000FT AGL AFTER MIDNIGHT AND LINGERING THROUGH THE FIRST
COUPLE OF DAYLIGHT HOURS ON WEDNESDAY.
FEW SPOTTY SHOWERS THAT DEVELOPED OVER THE INTERIOR SOUTH THIS PAST
AFTERNOON HAVE DISSIPATED WITH THE LOSS OF DIURNAL HEATING AND HAVE
REMOVED ALL MENTION OF SHOWERS IN THE FORECAST FOR THE REST OF THE
EVENING. HAVE ALSO UPDATED THE WX GRIDS TO FOLLOW CLOSELY THE SREF
VIS/FOG PATTERN FOR THE SECOND HALF OF THE NIGHT...AND UPDATED THE
SKY GRIDS TO ACCOUNT FOR THE MORE WIDESPREAD LOWER CLOUDS EXPECTED
BETWEEN 06-15Z. NEW UPDATED FORECASTS HAVE BEEN SENT.
A PLEASANT JANUARY DAY APPEARS IN STORE FOR WEDNESDAY ACROSS THE
REGION. UPPER LEVELS REMAIN ZONAL IN NATURE...WITH A POST FRONTAL
ENVIRONMENT DOWN LOW. THEREFORE WITH NO FOCUS FOR SYNOPTIC SUPPORT
LIFT...THE FORECAST WILL BE RAIN FREE. TEMPERATURES WILL BE
SEASONABLE WITH THE MID 60S TO NEAR 70 NORTH OF I-4...AND IN THE
LOWER TO MIDDLE 70S TRAVELING FURTHER SOUTH. WILL SEE SOME SUN ONCE
THE LOWER MORNING CLOUDS BEGIN TO BREAK UP...HOWEVER SHOULD BE
FILTERED THROUGH HIGH LEVEL CIRRUS WITH THE SUN FADING MORE WITH
TIME AS WE HEAD INTO THE LATER AFTERNOON HOURS.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA
THIS EVENING...AND SHOULD CONTINUE FOR SEVERAL MORE HOURS. AFTER
MIDNIGHT...SETUP APPEARS FAVORABLE FOR THE FORMATION OF WIDESPREAD
LOWER CLOUDS. HAVE BROUGHT ALL TERMINALS DOWN TO MVFR AFTER 06-08Z
WITH TEMPO PERIODS OF IFR FOR THE FEW HOURS SURROUNDING EITHER SIDE
OF DAWN. A FEW SPOTS SEEING CIGS BELOW 500FT IS NOT OUT OF THE
QUESTION...ALTHOUGH CONFIDENCE AT LIFR OR LOWER IS NOT HIGH YET.
WOULD EXPECT CIG RESTRICTIONS TO LINGER FOR MUCH OF THE
MORNING...ALTHOUGH SHOULD SEE MVFR ONLY AFTER 15Z. HAVE GONE A BIT
MORE OPTIMISTIC THAN THE STATISTICAL GUIDANCE IN BRINGING ALL SITES
BACK TO VFR AFTER 17Z.
&&
.MARINE...
MAINLY BENIGN PATTERN WILL CONTINUE WITH WINDS BELOW 15 KNOTS AND
SEAS 3 FEET OR LESS THROUGH THURSDAY NIGHT/EARLY FRIDAY MORNING. ON
FRIDAY...WINDS AND SEAS APPROACH CAUTIONARY LEVELS AS THE GRADIENT
BETWEEN AN EXITING COLD FRONT AND BUILDING HIGH PRESSURE TIGHTENS
ACROSS THE AREA. CONDITIONS WILL IMPROVE SATURDAY WITH WINDS AND
SEAS DIMINISHING BELOW CAUTIONARY CRITERIA...AS THE GRADIENT
LOOSENS. ANOTHER FRONT WILL APPROACH THE AREA LATE IN THE WEEKEND
AND COULD CAUSE CONCERN FOR MARINERS EARLY NEXT WEEK. CONSENSUS
BETWEEN MODEL GUIDANCE IS STRONG THROUGH MUCH OF THE PERIOD...WITH
CONSISTENT RESOLUTION OF THE SYNOPTIC FEATURES AND TIMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 61 72 55 67 / 0 10 10 30
FMY 62 77 58 75 / 0 10 10 20
GIF 59 72 53 69 / 0 10 10 30
SRQ 61 72 55 68 / 0 10 10 30
BKV 56 71 48 64 / 0 10 10 30
SPG 61 71 56 66 / 0 10 10 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION..MROCZKA
MARINE...GARCIA
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 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
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
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 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
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 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 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
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
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 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...UPDATED
NWS JACKSON MS
945 PM CST TUE JAN 13 2015
.UPDATE...
LIGHT DRIZZLE CONTINUES HERE AT THE OFFICE ALONG WITH REDUCED
VISIBILITIES DUE TO VERY LOW CLOUDS. THEREFORE ADDED THE POSSIBILITY
OF DRIZZLE INTO THE WX GRIDS THROUGH 12Z TONIGHT. THIS DRIZZLE COULD
POTENTIALLY CAUSE SOME PROBLEMS IF IT IS STILL AROUND WHEN
TEMPERATURES LOWER TO NEAR FREEZING TONIGHT. THIS IS SOMETHING TO
KEEP AN EYE ON AND AN EAR OUT FOR. AT THIS POINT...DO NOT THINK IT IS
WORRISOME ENOUGH TO ISSUE ANY ADVISORIES OR ANYTHING THOUGH. ONE
OTHER THING FOR THIS UPDATE...LOW TEMPS IN OUR MOST NW COUNTIES
DEPEND LARGELY ON HOW FAR THE EDGE OF THIS STRATUS DECK PROGRESSES
INTO OUR CWA. CURRENTLY THE EDGE APPEARS STATIONARY FOR NOW BUT WILL
VERY SLOWLY PROGRESS INTO THE CWA BY MORNING. TEMPS OVERALL LOOK FINE
FOR NOW. /10/
&&
.AVIATION...
WIDESPREAD MVFR/IFR CIGS WERE STILL BEING OBSERVED THIS EVENING
ALONG WITH SOME VSBY RESTRICTIONS OF 3-5SM OVER CNTRL MS. CIGS WL
LOWER TONIGHT RESULTING IN WIDESPREAD IFR CIGS WITH OCCASIONAL LIFR
CIGS AFTER 06Z. MOST SITES WL ALSO OBSERVE 2-3SM VSBYS AFTER 06Z.
MODELS CONTINUE TO SUGGEST SLOW IMPROVEMENT FROM THE NW WEDNESDAY
MORNING. /22/
&&
.PREV DISCUSSION... /ISSUED 413 PM CST TUE JAN 13 2015/
DISCUSSION...
TONIGHT THROUGH THURSDAY...
THE PRIMARY FORECAST CONCERN FOR TONIGHT INTO WEDNESDAY IS THE
CONTINUED COLD ADVECTION PATTERN AND ASSOCIATED LOW STRATUS. A FEW
BREAKS ARE SHOWING UP ON LATEST SATELLITE IMAGERY OVER THE DELTA
REGION...BUT GUIDANCE INDICATES THAT THE STRATUS DECK WILL RE-
SOLIDIFY IN NNE LOW LEVEL FLOW AND PERSIST THROUGH TONIGHT FOR MOST
OF THE ARKLAMISS. HAVE TRENDED THE FORECAST MORE PESSIMISTIC AND
SIMILAR TO THE HRRR GUIDANCE WHICH HAS BEEN SUPERIOR TODAY TO THE
OPTIMISTIC SREF. IT DOES LOOK LIKE THE LOW LEVEL COLD ADVECTION
PATTERN WILL SHUT DOWN WEDNESDAY MORNING AND THIS SHOULD ALLOW FOR
CLEARING.
ATTENTION WILL THEN TURN TO THE SHORTWAVE TROUGH SHEARING EASTWARD
ACROSS THE SOUTHERN PLAINS. THIS LOW AMPLITUDE WAVE WILL CAUSE JUST
ENOUGH BACKING OF THE LOW/MID LEVEL FLOW AND WARM ADVECTION TO
GENERATE LIGHT TO MODERATE RAIN...MAINLY AFFECTING THE HIGHWAY 84
CORRIDOR. MODELS HAVE BEEN TRENDING A LITTLE MORE BULLISH WITH QPF
AND EVEN SUGGEST SOME QUARTER TO HALF INCH RAINFALL AMOUNTS WILL BE
POSSIBLE FROM WED NIGHT INTO THURSDAY IN THE HATTISBURG AREA. HAVE
INCREASED MODEL BLEND GUIDANCE POPS SOME BASED ON THESE TRENDS...AND
ITS POSSIBLE THE RAIN CHANCES WILL HAVE TO BE INCREASED SOME MORE AS
GET CLOSER IN TIME. GUIDANCE THERMAL PROFILES CONTINUE TO SUGGEST AN
ALL RAIN EVENT. /EC/
THURSDAY NIGHT THROUGH MONDAY...GENERALLY DRY CONDITIONS AND
SEASONABLE TEMPERATURES WILL PREVAIL THROUGH THE EXTENDED PORTION OF
THE FORECAST.
SURFACE HIGH PRESSURE WILL SET UP SHOP OVER THE EASTERN QUARTER OF
THE COUNTRY THROUGH THE WEEKEND WITH A WEAKENING SUBTROPICAL JET
REMAINING FAIRLY ZONAL OVERHEAD. THU NIGHT/FRI MORNING WILL LIKELY BE
THE COOLEST PERIOD THROUGH THE LONG TERM AS THE SURFACE RIDGE IS
EXPECTED TO BE DIRECTLY OVER THE AREA. EASTERN PORTIONS OF THE CWA
MAY EEK OUT A RATHER COLD FRI NIGHT AS WELL AS THE RIDGE AXIS LINGERS
OVER THOSE AREAS A BIT LATER. WEAK RETURN FLOW WILL COMMENCE ON
SATURDAY...WITH TEMPS TRENDING SLIGHTLY ABOVE NORMAL FROM THE LATE
WEEKEND INTO EARLY NEXT WEEK. A BIT OF MODEL DISAGREEMENT EMERGES AT
THE END OF THE FORECAST AS THE GFS DEVELOPS A DEEPER UPPER TROUGH
OVER THE ATLANTIC COAST SUNDAY INTO MONDAY. THIS WOULD BRING A BIGGER
PUSH OF DRIER AIR THAN SUGGESTED BY THE EURO...WHICH ESSENTIALLY
MAINTAINS SOUTHERLY LOW LEVEL FLOW INTO MONDAY. WILL COMPROMISE AND
SHOW LOW END POPS MAINLY OVER THE WEST ON MONDAY. /DL/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 30 47 34 48 / 5 4 22 16
MERIDIAN 31 49 35 48 / 6 3 16 21
VICKSBURG 29 44 34 48 / 5 4 22 14
HATTIESBURG 35 52 39 50 / 5 7 41 30
NATCHEZ 30 46 34 48 / 5 6 39 21
GREENVILLE 27 41 31 46 / 4 3 10 9
GREENWOOD 27 44 31 46 / 4 2 8 9
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
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 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 BURLINGTON VT
930 PM EST TUE JAN 13 2015
.SYNOPSIS...
STRONG ARCTIC HIGH PRESSURE OVER THE NORTH COUNTRY TODAY WILL
CONTINUE TO PROVIDE CLEAR SKIES, LIGHT WINDS AND BELOW NORMAL
TEMPERATURES TO THE REGION THROUGH WEDNESDAY NIGHT. MILDER
TEMPERATURES RETURN FOR THURSDAY AS THE HIGH DRIFTS OFF THE
ATLANTIC SEABOARD, BUT ANOTHER ARCTIC FRONT WILL BRING THE COLD
BACK FRIDAY ALONG WITH THE CHANCE FOR SOME LIGHT SNOW SHOWERS.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 930 PM EST TUESDAY...MODEST ADJUSTMENTS TO LOWER MINIMUM
TEMPERATURES ACROSS PORTIONS OF THE FORECAST AREA OVERNIGHT AND TO
DEPICT SHALLOW NATURE OF ARCTIC AIR INDICATING MUCH WARMER
TEMPERATURES ACROSS THE HIGHER SUMMITS. LATEST ANALYSIS PLACES
LARGE 1042 MB SFC HIGH NEARLY ATOP THE FORECAST AREA INTO SRN
QE/ON AS OF 9 PM WITH CLEAR SKIES AND LIGHT TERRAIN-DRIVEN
DRAINAGE WINDS GENERALLY LESS THAN 5 KTS. OPTIMAL RADIATIVE
EFFECTS CONTINUE AND SOME OF THE COLDER SPOTS ACROSS THE SLV AND
NE KINGDOM ALREADY APPPROACHING -20F AT THIS EARLY HOUR. AS A
MATTER OF COURSE THIS PREDICATED A BROAD ADJUSTMENT DOWNWARD OF
TEMPERATURES IN MANY LOCALES OVERNIGHT. 01Z RAP DATA APPEARED TO
HAVE THE BEST HANDLE ON CURRENT SITUATION...BUT ADMITTEDLY ALL
MODELS ARE STRUGGLING WITH THE MESO/MICROSCALE PROCESSES UNDER
SUCH CONDITIONS. FASCINATING TO SEE THE SHALLOW DEPTH OF THE
ARCTIC AIR...WITH SUMMIT TEMPERATURES REMAINING IN THE POSITIVE
SINGLE DIGITS INTO THE TEENS. WHITEFACE SUMMIT CURRENTLY +16F.
REST OF FORECAST IN GREAT SHAPE SHOWING CLEAR SKIES AND NIL POPS
INTO TOMORROW MORNING. HAVE A GREAT NIGHT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 307 PM EST TUESDAY...AS THE HIGH BEGINS TO DRIFT EAST OFF
THE ATLANTIC SEABOARD THE AIRMASS MODIFIES WEDNESDAY, SO AFTER A
FRIGID START TO THE DAY TEMPS WILL REBOUND INTO THE MID TEENS OVER
THE NORTHERN VALLEYS TO THE LOWER 20S SOUTH UNDER SUNNY SKIES.
ANOTHER CHILLY AND CLEAR NIGHT IS IN STORE FOR THE NORTH COUNTRY
WEDNESDAY NIGHT, BUT RETURN SOUTHERLY FLOW WILL ALLOW FOR
CONTINUED MODERATION IN TEMPS WITH LOWS GENERALLY IN THE SINGLE
DIGITS ABOVE AND BELOW ZERO.
TEMPS TREND BACK TO NORMAL FOR THURSDAY AS SOUTHERLY FLOW
INCREASES FURTHER AHEAD OF AN APPROACHING ARCTIC FRONT (YES,
ANOTHER ONE) TRACKING NORTH OF THE BORDER FROM ONTARIO TO QUEBEC.
WE`LL SEE A GENERAL INCREASE IN CLOUD COVER THROUGH THE DAY BUT
CONDITIONS WILL REMAIN DRY UNTIL THE FRONT SHIFTS INTO THE REGION
THURSDAY NIGHT. LATEST GUIDANCE HAS THE FRONT RIGHT ON THE
DOORSTEP OF THE BTV CWA LATE THURSDAY NIGHT INTO EARLY FRIDAY
MORNING SO THE MIN TEMP FORECAST IS RATHER TRICKY RIGHT NOW.
THINKING SINGLE DIGITS WEST TO TEENS EAST WITH ONLY A CHANCE OF
SNOW SHOWERS AS RH PROFILES ARE RATHER DRY. MAYBE WE`LL SEE A
DUSTING TO AN INCH, SIGH.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 247 PM EST TUESDAY...UPPER LEVEL TROUGH WILL MOVE ACROSS
THE NORTH COUNTRY...PROVIDING THE CHANCE FOR SNOW SHOWERS,
ESPECIALLY OVER THE HIGHER TERRAIN AS MOISTURE WILL BE SOMEWHAT
LACKING. BEHIND THIS TROUGH, COLDER AIR WILL FILTER IN ON
NORTHWEST FLOW...BRINGING MAX TEMPS ON FRIDAY IN THE TEENS TO MID
20S DOWN TO SINGLE DIGITS ON EITHER SIDE OF ZERO FOR FRIDAY NIGHT
AS SURFACE HIGH PRESSURE SLIDES OVER THE REGION...CRESTING EARLY
SATURDAY MORNING.
RETURN FLOW THROUGHOUT THE DAY SATURDAY, AS THE SURFACE HIGH
SLIDES INTO THE ATLANTIC, WILL WARM TEMPERATURES INTO THE UPPER
TEENS TO NEAR 30. AT 500MB, AN OPEN WAVE WILL APPROACH...REFLECTED
AT THE SURFACE AS CLIPPER TYPE LOW. BULK OF THE MOISTURE OF THIS
SYSTEM WILL REMAIN IN QUEBEC SATURDAY NIGHT, AS THE SURFACE LOW
TRACKS SOUTH OF JAMES BAY. SOUTHERLY FLOW AND WAA CONTINUES MONDAY
WITH TEMPERATURES REACHING ABOVE FREEZING AND NEARING 40 IN SOME
AREAS SUNDAY. ANOTHER SHOT OF COLD AIR WILL SPREAD ACROSS THE AREA
AS N/NW FLOW DEVELOPS MONDAY, BEHIND THE CLIPPER TYPE LOW.
SOUTHERN STREAM UPPER LEVEL ENERGY LOOKS TO INTERACT WITH
NORTHERN STREAM...POSSIBLY DEVELOPING A COASTAL SURFACE LOW WHICH
COULD KEEP CHANCE FOR SNOW SHOWERS ACROSS THE NORTH COUNTRY INTO
THE WORK WEEK. CONFIDENCE LOW ON EVOLUTION AND TRACK OF THIS
SYSTEM AS THERE IS MUCH MODEL DISAGREEMENT. THEREFORE WENT WITH
SLIGHT CHANCE POPS MONDAY ONWARD.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 00Z THURSDAY...VFR EXPECTED AT ALL TAF SITES THROUGH THE
PERIOD. CLEAR SKIES AND LIGHT AND LOCALLY VARIABLE WINDS PERSIST
THROUGH WEDNESDAY MORNING...WITH WINDS TURNING LIGHT SOUTHERLY
(5-10 KNOTS) FROM LATE WEDNESDAY MORNING AND INTO THE AFTERNOON.
OUTLOOK 00Z THURSDAY THROUGH SUNDAY...
00Z THURSDAY-00Z FRIDAY...VFR UNDER HIGH PRESSURE.
00Z FRIDAY-00Z SATURDAY...MAINLY VFR ALTHOUGH A PERIOD OF
MVFR/IFR POSSIBLE IN LIGHT SNOW SHOWERS WITH NEXT COLD FRONTAL
PASSAGE.
00Z SATURDAY-00Z SUNDAY...HIGH PRESSURE WITH VFR CONDITIONS.
00Z SUNDAY ONWARD...VFR WITH MVFR/IFR WITHIN SCATTERED SNOW
SHOWERS.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...LAHIFF
NEAR TERM...JMG
SHORT TERM...LAHIFF
LONG TERM...KGM
AVIATION...KGM/MUCCILLI
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 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
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
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 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 TULSA OK
938 PM CST TUE JAN 13 2015
...UPDATE...
.DISCUSSION...
UPDATED FORECAST THIS EVENING TO INCLUDE SOME LOW CHANCE POPS
ACROSS NORTHEAST OKLAHOMA LATE TONIGHT INTO THE DAY WEDNESDAY.
LOCAL WRF AND HRRR HINTING AT THE POTENTIAL FOR WIDELY SCATTERED
AREAS OF LIGHT SNOW/SLEET DURING THIS TIME. LATEST 00Z NAM ALSO
DEVELOPS SOME LIGHT PRECIP DURING THE DAY WEDNESDAY NORTH OF
INTERSTATE 44 AS MAIN UPPER LEVEL JET STREAK SHIFTS INTO THE
REGION. ANY SNOW ACCUMULATIONS WOULD BE LIGHT AND FAIRLY
LOCALIZED WITH NO WIDESPREAD IMPACTS. THIS WILL CONTINUE TO BE
MONITORED AS ADDITIONAL DATA BECOMES AVAILABLE.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...12
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 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 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
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 THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
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.
&&
$$
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 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 PHOENIX AZ
950 PM MST TUE JAN 13 2015
.SYNOPSIS...
AN EXITING WEATHER SYSTEM WILL AFFECT EASTERN ARIZONA THROUGH EARLY
WEDNESDAY...KEEPING CHANCES FOR SHOWERS ACROSS HIGHER TERRAIN AREAS
EAST OF PHOENIX. BEHIND THIS SYSTEM...MUCH DRIER AIR AND
LOCALLY BREEZY CONDITIONS WILL FILTER SOUTH INTO THE AREA. HOWEVER
AFTER THIS SYSTEM PASSES...HIGH PRESSURE WILL RETURN WITH SLOWLY
INCREASING TEMPERATURES THROUGH THE WEEKEND.
&&
.DISCUSSION...
UPPER LOW CENTERED OVER THE COLORADO PLATEAU THIS EVENING. CLOUDS
AND SHOWERS ARE CURRENTLY LIMITED TO ROUGHLY THE NORTHEAST HALF OF
ARIZONA. SHOWER ACTIVITY HAS PRETTY MUCH ENDED OVER OUR FORECAST
AREA AS DRIER AIR MOVES IN. MADE SOME UPDATES TO DECREASE THE POPS
SIGNIFICANTLY THE REST OF THE NIGHT...REMOVING SLIGHT CHANCES FROM
PHOENIX AREA. OF NOTE...RAP AND HRRR APPEAR TO HAVE OVERDONE THE
PRECIP OVER MARICOPA COUNTY FOR THIS EVENING...ESPECIALLY THE HRRR.
HELD ON TO SLIGHT CHANCE OVER SOUTHERN GILA COUNTY AND FAR NORTHEAST
MARICOPA COUNTY DUE TO CLOSE PROXIMITY OF THE UPPER LOW CENTER AND
THE PASSAGE OF AT LEAST ONE MORE VORT LOBE PER LATEST MODELS. ALSO
HELD ON TO SLIGHT CHANCES THERE FOR DAY TIME WEDNESDAY DUE TO
INSTABILITY ASSOCIATED WITH PASSAGE OF UPPER LOW CENTER. MODELS
AGREE IT WILL BE ONLY AREA IN OUR CWA FOR QPF. MADE ANOTHER
ADJUSTMENT TO THE FORECASTS FOR TONIGHT AND WEDNESDAY MORNING TO ADD
MENTION OF PATCHY FOG FOR SOUTH-CENTRAL ARIZONA SINCE A NUMBER OF
PLACES HAD MORE THAN TWO-TENTHS OF AN INCH OF PRECIP...SKIES WILL BE
MOSTLY CLEAR...AND WINDS WILL BE LIGHT. HOWEVER...LARGE SCALE
SUBSIDENCE WILL NOT BE UNDERWAY YET AND THERE MAY BE JUST ENOUGH
MIXING TO PRECLUDE FOG DEVELOPMENT. THUS ANTICIPATE THAT IT WILL
MOSTLY BE HAZE WITH VISIBILITY ABOVE 3 MILES BUT ISOLATED
SPOTS...EVEN IN PHOENIX METRO...THAT WILL HAVE LOWER VIS.
OTHERWISE...ANTICIPATE COLDER TEMPS TONIGHT/WEDNESDAY MORNING
FOLLOWED BY SOME CUMULUS DEVELOPMENT DURING THE DAY BUT WITH ANY
PRECIP CONFINED TO THE HIGHER MOUNTAINS.
&&
.PREVIOUS DISCUSSION ISSUED 202 PM MST/102 PM PST...
A FAIRLY IMPRESSIVE RAIN BAND WITH EMBEDDED MODERATE TO EVEN HEAVY
SHOWERS MOVED OUT OF CENTRAL ARIZONA THIS MORNING INTO THE PHOENIX
AREA LATE IN THE MORNING...AND NOW IS PUSHING INTO THE MOUNTAINS TO
THE EAST. RAINFALL AMOUNTS WERE GENERALLY AROUND A TENTH OF AN
INCH...BUT THERE WERE A FEW LOCALIZED AMOUNTS OF A QUARTER INCH OR
MORE. THE UPPER TROUGH RESPONSIBLE FOR THIS RAIN IS NOW CENTERED
OVER NORTHWEST ARIZONA...BUT THE MAJORITY OF THE VERTICAL ASCENT IS
NOW SITUATED OVER SOUTHEAST ARIZONA NEAR A 120 KT UPPER JET STREAK.
DRY AIR ALOFT CAN BE SEEN ON WATER VAPOR IMAGERY TO THE SOUTH OF THE
UPPER LOW CENTER OVER SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA.
THIS DRY AIR ALONG WITH GRADUALLY INCREASING SUBSIDENT FLOW ALOFT
SHOULD KEEP OUR RAIN CHANCES FOR THE REST OF TODAY MAINLY LIMITED TO
HIGHER TERRAIN AREAS EAST OF PHOENIX. HOWEVER...VISIBLE IMAGERY DOES
SHOW A GOOD AMOUNT OF SUNSHINE TO THE WEST OF PHOENIX AND SOME CU
DEVELOPMENT OVER THE PAST HOUR. MAY SEE A FEW SHOWERS FORM IN THESE
SUNNY AREAS THROUGH THE REST OF THE AFTERNOON...BUT WITH VERY
LIMITED INSTABILITY...ANY DEVELOPMENT SHOULD REMAIN ISOLATED.
THE LATEST HI-RES HRRR AND WRF4KM RUNS SHOWS THE BULK OF THE RAIN
ENDING BY EARLY EVENING. THERE WILL BE A LINGERING CHANCE OF SOME
SHOWERS ACROSS EASTERN ARIZONA DURING THE OVERNIGHT HOURS AS THE
MAIN VORT MAX AND PVA ANOMALY CURRENTLY OVER NORTHWEST ARIZONA
SLIDES SOUTHEASTWARD. NOT WORRIED ABOUT THE CHANCES FOR MUCH SNOW
TONIGHT AS THE SYSTEM IS NOT UNUSUALLY COLD OR DEEP AND
HEIGHTS/THICKNESSES ALOFT INDICATE FREEZING LEVEL REMAINING AOA 7K
FT. THEREFORE...SNOW LEVELS SHOULD REMAIN WELL ABOVE POPULATION
CENTERS/TRANSPORTATION CORRIDORS WITH ONLY A DUSTING ON THE PEAKS OF
SRN GILA COUNTY LATER TONIGHT. AS THE LOW CENTER AND COLD CORE
SHIFTS OVER EAST-CENTRAL ARIZONA DURING THE DAYTIME HOURS
WEDNESDAY...WE SHOULD SEE SOME DIURNALLY FORCED SCT RAIN/SNOW SHOWER
REDEVELOPMENT WITHIN THE COLD CORE...BUT PRIMARILY LIMITED TO THE
WHITE MOUNTAINS OF ERN ARIZONA.
OPERATIONAL AND ENSEMBLE MEMBERS ARE IN VERY GOOD AGREEMENT THAT
STRONGER ZONAL PACIFIC JET ENERGY WILL FORCE A SIGNIFICANT
DOWNSTREAM PATTERN SHIFT OVER THE WESTERN HEMISPHERE DURING THE
LATTER HALF OF THIS WEEK INTO NEXT WEEK...UNLOCKING THE PREVAILING
BLOCKED FLOW INTO A MORE PROGRESSIVE QUASI-ZONAL PATTERN. SHORTWAVE
FEATURES OVER THE CONUS WILL BE EXCLUSIVELY LOW AMPLITUDE AND
RELEGATED TO THE NORTHERN STREAM WITH FLAT RIDGING PREDOMINATING THE
SWRN REGION. AS A RESULT...ENSEMBLE GUIDANCE EXHIBITS VERY LOW
FORECAST SPREAD WITH H5 HEIGHTS OSCILLATING AROUND A 580DM RANGE AND
H8 TEMPERATURES NEAR +10C. BASED ON HISTORICAL BIASES DURING SIMILAR
PATTERN EVOLUTION...HAVE HEDGED TOWARDS THE WARMEST GUIDANCE
PACKAGES YIELDING FORECAST HIGHS AT LEAST 5F ABOVE AVERAGE. EVEN
THIS APPROACH MAY BE CONSERVATIVE GIVEN A DRY ENVIRONMENT AND
POTENTIALLY SEVERAL DAYS OF FULL INSOLATION.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
THE UPPER LOW...CENTERED OVER COLORADO PLATEAU AS OF 04Z...WILL
SLOWLY MOVE SOUTH-SOUTHEASTWARD. HOWEVER SHOWERS AND CEILINGS PRETTY
MUCH DONE FOR THE NIGHT AS DRIER AIR HAS STARTED TO MOVE IN...EXCEPT
POSSIBLY NEAR HIGHER MOUNTAINS AND FOOTHILLS MAINLY NORTH AND EAST
OF PHOENIX AREA. ANTICIPATE HIGHER MOUNTAIN TOPS TO BE OBSCURED.
LINGERING LOW LEVEL MOISTURE...MOSTLY CLEAR SKIES...AND LIGHT WINDS
MAY LEAD TO AREAS OF HAZE/MIST AFTER 08Z LOWERING VISIBILITIES BELOW
10SM AND POSSIBLY BELOW 5SM. SOME ISOLATED SPOTS COULD DIP BELOW
3SM. IF THIS OCCURS...SLANT VISIBILITIES WILL ALSO BE REDUCED EVEN
IF SURFACE VIS IS AOA 6SM. THIS SCENARIO MAY VERY WELL NOT
MATERIALIZE DUE TO LACK OF STRONG DISTINCT SUBSIDENCE. SURFACE
WINDS WILL REMAIN LIGHT WITH LOWER LEVEL WINDS TRENDING TOWARD
EASTERLY DIRECTIONS OVERNIGHT. THERE MAY BE SOME CUMULUS
REDEVELOPMENT DURING THE DAY WEDNESDAY BUT EXPECT ANY CEILINGS TO BE
OVER HIGHER TERRAIN WELL EAST OF PHOENIX AREA.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
EXPECT NORTHERLY SURFACE WINDS TO CONTINUE TRANSITIONING TO FAVORED
NOCTURNAL DIRECTIONS 06Z. ANTICIPATE MODERATE NORTHERLY
SURFACE WINDS CONTINUING IN THE LOWER LEVELS ABOVE THE INVERSION
OVERNIGHT WITH RESUMPTION OF NORTHERLY SURFACE WINDS BY 18Z
WEDNESDAY...GUSTS REMAINING BELOW 15 KTS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
UPPER LEVEL RIDGING WILL TAKE SHAPE ACROSS THE REGION BY FRIDAY AND
REMAIN LARGELY IN PLACE THROUGH EARLY NEXT WEEK. THIS WILL RESULT IN
INCREASED TEMPERATURES WITH DAILY HIGH TEMPERATURES SEVERAL DEGREES
OR MORE ABOVE SEASONAL NORMALS EACH DAY. DESPITE THE PRESENCE OF
HIGH PRESSURE...HUMIDITIES WILL STAY A BIT ELEVATED EACH DAY WITH
MINIMUM RH VALUES MOSTLY BETWEEN 15 AND 25 PERCENT ACROSS THE
DESERTS. WINDS THROUGH THE PERIOD WILL BE LIGHT AND GENERALLY
DIURNAL IN NATURE.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...KUHLMAN/MO
AVIATION...AJ
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
913 PM MST TUE JAN 13 2015
.UPDATE...
ISSUED AT 912 PM MST TUE JAN 13 2015
UPPER CLOSED LOW IS SINKING INTO CENTRAL AZ. WEAK JET STREAK ON
THE NNE SIDE OF THE LOW SINKS THROUGH UTAH OVERNIGHT. THIS IS
PRODUCING SOME DEFORMATION OVER THE CENTRAL FORECAST AREA THIS
EVENING WITH MILD CONVECTIVE CELLS AND SHOWERS POPPING MAINLY
OVER THE CENTRAL CWA HIGHER TERRAIN. OTHERWISE LIGHT SHOWERS WILL
CONTINUE OVER THE SOUTHERN ZONES TONIGHT WHERE THE DEEPER MOISTURE
LINGERS. FOG MAY BE A CONCERN ESPECIALLY ALONG THE SLOPES OF THE
SOUTHERN AND CENTRAL MTNS INTO WEDNESDAY MORNING. EXPECT MILD LOW
TEMPERATURES TONIGHT FOR THE SOUTHERN AND CENTRAL ZONES BUT COLDER
THAN NORMAL ACROSS THE DRIER NORTH.
UPDATE ISSUED AT 616 PM MST TUE JAN 13 2015
ALLOWED ALL WARNINGS AND ADVISORIES TO EXPIRE AT 6 PM LOCAL TIME.
LIGHT ACCUMULATIONS MAY CONTINUE THIS EVENING OVER THE SWRN SAN
JUAN MOUNTAINS...BUT THE BRUNT OF THE HEAVY SNOW HAS ENDED.
THE OTHER FORECAST QUESTION THAT NEEDS TO BE MONITORED IS FOG
FORMATION. MAY BE SUFFICIENT CLOUD COVER OR WIND CIRCULATION TO
PREVENT WIDESPREAD LOW LYING FOG...BUT THE TREND WILL BE FOR
CLEARING SKIES OVERNIGHT.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 253 PM MST TUE JAN 13 2015
UPPER LEVEL LOW HAS JUST DROPPED BELOW THE UTAH STATE LINE INTO
ARIZONA AS MOIST SWLY FLOW CONTINUES TO PUMP MOISTURE INTO THE
REGION. ALONG AND JUST N OF INTERSTATE 70...FLOW HAS TURNED
EASTERLY WITH RADAR SHOWING RETURNS THAT ARE MORE CONVECTIVE IN
NATURE. ALL MODELS CONTINUE TO HIGHLIGHT A RATHER BROAD AREA OF
DEFORMATION THAT APPEARS TO BE PANNING OUT WITH SOME DISTINCT
BANDS OF PRECIP HAVING SET UP OVER THE REGION. UNDER THESE
BANDS...EXPECT PRECIP TO PICK UP SOME BUT COVERAGE LOOKS TO BE
SOMEWHAT LIMITED SO DO NOT ANTICIPATE MUCH OF AN INCREASE TO RAIN
AND SNOW TOTALS. SPEAKING OF...MANY REPORTS OF DECENT SNOWFALL
WITH MONTEZUMA COUNTY REPORTING 6 TO 8 INCHES...LA PLATA COUNTY
CAME IN WITH 6 TO 10 INCHES AND ARCHULETA COUNTY REPORTS 8 TO 12
INCHES IN SOME SPOTS. NAM12 CONTINUES TO SHOW RATHER WIDESPREAD
PRECIP FOR THE SAN JUANS AND AREAS SOUTH THROUGH TONIGHT BUT THIS
LOOKS WAY OVERDONE. HRRR IS MUCH MORE CONSERVATIVE AND ALSO SHIFTS
THE BEST PRECIP SOUTHWARD INTO NEW MEXICO. VISIBLE SATELLITE DOES
SHOW PLUME OF MOISTURE STEADILY DROPPING EAST AND SOUTH SO THINK
HRRR HAS THE BEST HANDLE ON CURRENT SITUATION. FOR THE REMAINDER
OF THE DAY THEN...A FEW MORE INCHES...1 TO 3...FOR THE MOUNTAINS
WITH VALLEYS POSSIBLY SEEING ANOTHER INCH OR TWO. CURRENT HIGHLIGHTS
CONTINUE THROUGH 6PM SO WILL KEEP THEM GOING.
FOR WEDNESDAY...HIGH PRESSURE BUILDS IN WITH LESS CLOUDS UP NORTH
AND MORE DOWN SOUTH WITH CONDITIONS IMPROVING THROUGH THE DAY. ONLY
BIG QUESTION MARK WILL BE FOG AND HOW THICK AND HOW WIDESPREAD IT
WILL BE AS AMPLE MOISTURE WILL REMAIN IN THE ATMOSPHERE DUE TO THE
EVAPORATING SNOWFALL ESPECIALLY SOUTH. TEMPS WILL STAY NEAR
NORMAL THROUGH THE PERIOD WITH A WARMUP TOWARDS THE END OF THE
WEEK.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 253 PM MST TUE JAN 13 2015
A PROGRESSIVE FLOW WILL BRING A SERIES OF RIDGES AND TROUGHS
ACROSS THE CONUS DURING THE LONG TERM PERIOD. FOR THE MOST
PART...OUR FORECAST AREA WILL BE SOUTH OF...OR ON THE SOUTHERN
EDGE AT BEST OF ANY WEATHER ASSOCIATED WITH ANY DISTURBANCE THAT
PASSES. ALSO TIMING WILL REMAIN DIFFICULT FOR THESE FAST MOVING
WAVES.
ON THU AT THE START OF THE PERIOD. THE AREA WILL BE UNDER A
FLATTENING RIDGE THAT WASHES OUT AS IT GETS PUSHED EAST THU NIGHT.
A SHORTWAVE TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST ON
FRIDAY...THEN WILL BRUSH OUR FORECAST AREA FRI NIGHT INTO SAT.
EXCEPT FOR THE LATEST/12Z ECMWF...THE MODELS HAVE INDICATED THAT
THIS WAVE WILL JUST BARELY BRUSH OUR NORTHEAST CORNER...WITH THE
FLOW MAINLY STAYING ZONAL. THE 12Z EC HOWEVER IS MORE AMPLIFIED
THAN EARLIER RUNS WHICH COULD MEAN A BETTER CHANCE OF SNOW...STILL
STAYING MAINLY OVER THE NORTH AND CENTRAL CO MOUNTAINS. WILL KEEP
THE GENERALLY DRY FORECAST FOR NOW BEFORE BUYING OFF ON THIS
STRENGTHENING TREND.
A RIDGE WILL BUILD BEHIND THIS WAVE ON SUN...THEN FLATTEN AGAIN
DURING THE EARLY PART OF THE WORK WEEK AS WAVES MOVES INTO WESTERN
NOAM. EXPECT TEMPERATURES TO RUN JUST A LITTLE ABOVE NORMAL FOR
THE MOST PART. THE MEX AND ECE GUIDANCE NUMBERS SHOW RATHER BIG
DIFFERENCES...WITH THE MEX PROBABLY TOO WARM AND ECE TOO COOL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED
AT 912 PM MST TUE JAN 13 2015
LOW CIGS WITH AREAS OF SNOW PERSIST FROM THE I-70 CORRIDOR
SOUTHWARD. THESE CONDITIONS WILL IMPROVE TONIGHT AS SHOWER COVERAGE
CONTINUES TO DECREASE. TAF SITES IN ERN UTAH AND NW COLORADO WILL
BE AT VFR TONIGHT...THOUGH KDRO CIGS MAY BE AT OR BELOW ILS
APPROACH HEIGHT AT TIMES THROUGH 15Z.
LOCAL FOG MAY LIMIT VISIBILITY ALONG RIVER VALLEYS AND LOW LYING
AREAS LATE TONIGHT. CLOUD COVER OR WIND CIRCULATIONS MAY BE
SUFFICIENT TO KEEP TAF SITES FREE FROM FOG...BUT THIS NEEDS TO BE
MONITORED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JOE
SHORT TERM...TGR
LONG TERM...EH
AVIATION...PF/JOE
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1255 AM EST WED JAN 14 2015
.SYNOPSIS...
COLD HIGH PRESSURE WILL EXTEND SOUTH INLAND FROM THE COAST
THROUGH WEDNESDAY AS WEAK LOW PRESSURE DEVELOPS AND LIFTS
NORTHEAST WELL OFFSHORE. HIGH PRESSURE WILL GRADUALLY BUILD IN
FROM THE WEST LATE IN THE WEEK AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1250 AM WEDNESDAY...LIGHT PRECIPITATION SHIELD CONTINUES TO
LIFT NORTHEAST ACROSS THE CENTRAL AND NORTHERN COASTAL PLAINS AND
SOUND COUNTIES. TEMPERATURES HAVE DROPPED TO 32 DEGREES AT
KPGV...KISO AND KDPL...BUT THE REMAIN OF THE REGION REMAINS AT 34
DEGREES OR HIGHER. SURFACE OBSERVATIONS HAVE INDICATED SOME LIGHT
FREEZING RAIN/SLEET AT THESE LOCATIONS. SOME CHANGES MADE TO THE
FORECAST IN TERMS OF TIMING AND EXTENT OF PRECIPITATION PER LATEST
3KM HRRR AND 4KM NSSL WRF MODELS...WHICH SHOW BULK OF THE
PRECIPITATION SHOULD DIMINISH OVER THE WINTER WEATHER ADVISORY
AREA OVER THE NEXT FEW HOURS...WITH ADDITIONAL PRECIPITATION LATE
TONIGHT BEING CONFINED TO NEAR THE COAST WHERE TEMPERATURES ARE IN
THE UPPER 30S TO MID 40S. WILL MAKE NO CHANGES TO THE ADVISORY AT
THIS TIME HOWEVER...AS FAR WESTERN AREAS MAY SEE SOME ADDITIONAL
LIGHT FREEZING RAIN/SLEET THROUGH 08Z OR SO AND WILL CONTINUE TO
MONITOR.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TODAY/...
AS OF 245 PM TUESDAY...WIDESPREAD PRECIP WILL TAPER OF AND END
FROM SW TO NE WED MORN INTO EARLY AFTN. WILL CONT WINTER WX
ADVISORY INLAND THRU LATE MORN AS TEMPS WILL STRUGGLE TO RISE
GIVEN PERSISTENT NRLY FLOW AND CLOUDS. DURING AFTN PATCHY LIGHT
RAIN OR DRIZZLE WILL BE POSS ESPCLY NE SECTIONS. HIGHS MAINLY
MID/UPR 30S INLAND TO NEAR 50 CAPE HAT. WITH WEAK LOW OFFSHORE
NRLY WINDS WILL REMAIN GUSTY ALONG THE COAST.
&&
.LONG TERM /TONIGHT THROUGH TUESDAY/...
AS OF 250 PM TUE...LOW PRESSURE WELL OFFSHORE WILL CONTINUE TO PUSH
NE WED NIGHT WITH LIGHT RAIN/DRIZZLE TAPERING OFF FROM WEST TO
EAST. LINGERING MOISTURE ON ROADWAYS COULD LEAD RE-FREEZING AND
ICY SPOTS WED NIGHT INTO THURSDAY MORNING. WILL CONTINUE SC PRECIP
FOR THU...BUT OVERALL EXPECT LIMITED COVERAGE. LOW LEVEL THICKNESS
VALUES AND CLOUDS SUPPORT HIGHS IN THE 40S THU. SHORTWAVE WILL
MOVE THROUGH THE REGION THU NIGHT...PUSHING OFF THE SE COAST EARLY
FRIDAY WITH SKIES GRADUALLY CLEARING. SFC HIGH WILL BUILD IN FROM
THE WEST THU NIGHT THROUGH THE WEEKEND...WITH AREA DRYING OUT AND
GRADUAL WARM UP. BY SAT/SUN HIGHS IN THE MID 50S TO AROUND 60.
HIGH PRESSURE WILL MOVE OFF THE COAST SAT NIGHT SUNDAY. NEXT
FRONTAL SYSTEM IS EXPECTED TO MOVE THROUGH THE AREA LATE SUN.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
SHORT TERM /THROUGH 06Z THURSDAY/...
AS OF 1250 AM WEDNESDAY...IFR CEILINGS AT ALL TAF SITES WITH LIGHT
PRECIPITATION OCCURRING. THIS PRECIPITATION SHOULD GRADUALLY END
OVER THE NEXT SEVERAL HOURS...BUT IFR CEILINGS WILL PREVAIL
THROUGH THE DAY ALONG WITH MODERATE NORTHERLY WINDS. EXPECT SOME
PATCHES OF FOG TO RETURN BY TONIGHT ACCOMPANIED BY CEILINGS AROUND
500-700 FEET OR SO.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 PM TUE...SUB-VFR CONDITIONS EXPECTED TO PERSIST WEDNESDAY
NIGHT THEN GRADUALLY IMPROVE TO VFR THROUGH THE DAY THU WITH CIGS
LIFTING. HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST THU
NIGHT INTO THE WEEKEND...WITH PRED VFR CONDITIONS.
&&
.MARINE...
SHORT TERM /THROUGH WEDNESDAY/...
AS OF 1255 AM WEDNESDAY...GUSTY NORTH WINDS CONTINUE ON THE
COASTAL WATERS AND SOUNDS AND NO CHANGES TO THE CURRENT ADVISORIES
AS DUCK IS GUSTING TO 32 KNOTS AND CAPE LOOKOUT TO 25 KNOTS AT
THIS TIME. ALSO PICKING UP 27 KNOT WINDS ON THE ALBEMARLE SOUND.
SEAS CONTINUE IN THE 9 TO 11 FOOT RANGE.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 250 PM TUE...GUSTY NLY WINDS 15-25KT WILL CONTINUE WED
NIGHT THEN GRADUALLY TAPERING OFF AS LOW PRESSURE WELL OFFSHORE
CONTINUES TO MOVE NE. ELEVATED SEAS 5-9FT CONTINUE WED NIGHT
SUBSIDING TO 4-7FT THU AFTERNOON. MAIN CHANGE TO FORECAST WAS TO
END SCA EARLIER THAN PREVIOUS FORECAST BASED ON LATEST
GUIDANCE...WITH SEAS SUBSIDING BELOW 6FT THURSDAY NIGHT. SFC HIGH
PRESSURE WILL GRADUALLY BUILD INTO THE WATERS FROM THE WEST THU
NIGHT THROUGH THE WEEKEND. NWLY WINDS 10-20KT THU NIGHT INTO
FRI...BECOMING SE 10KT OR LESS SAT AFTERNOON. HIGH PRESSURE WILL
MOVE OFFSHORE SAT NIGHT...WITH SWLY FLOW 10-20KT DEVELOPING ACROSS
THE WATERS SUN.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NCZ029-044-045-079-080-090>093-098.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ130-
131-135.
SMALL CRAFT ADVISORY UNTIL 1 AM EST FRIDAY FOR AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...RF
NEAR TERM...CTC
SHORT TERM...RF
LONG TERM...CQD
AVIATION...CTC/CQD
MARINE...CTC/CQD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1234 AM EST WED JAN 14 2015
.SYNOPSIS...
FREEZING LIGHT RAIN AND PATCHY ICY SURFACES ARE POSSIBLE OVERNIGHT
AND EARLY WEDNESDAY FOR PARTS OF INTERIOR SOUTHEAST NORTH
CAROLINA AND NORTHEAST SOUTH CAROLINA. DESPITE A COLD DAY ON
WEDNESDAY...A SLOW WARMING SHOULD MELT ANY ICE THAT FORMS BY LATE
MORNING. WEAK HIGH PRESSURE WILL BRING A DRYING TREND THURSDAY. A
GULF OF MEXICO DISTURBANCE COULD BRING PATCHY LIGHT RAIN EARLY ON
FRIDAY. FAIR AND MILDER CONDITIONS ARE EXPECTED THIS WEEKEND
BEFORE A COLD FRONT MOVES THROUGH SUNDAY NIGHT. BUILDING HIGH
PRESSURE FROM THE NORTH WILL BRING A COOLING TREND EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 12:30 AM WEDNESDAY...CONTINUED WITH NO CHANGES NEEDED FOR
THE CURRENT WINTER WX ADVISORY IN EFFECT FOR MUCH OF THE INLAND
PORTIONS OF THE ILM CWA.
THE FA IS STILL LOOKING AT A STRATUS TYPE LIGHT PCPN EVENT...WITH
THE POSSIBILITY OF FREEZING RAIN AND/OR DRIZZLE OCCURRING...IF
ENOUGH COLD AIR GETS FUNNELED SOUTHWARD BEFORE THE PCPN EVENT ENDS
COME MID TO LATE WED MORNING.
ONCE AGAIN...THE LATEST SFC TEMP/DEWPT READINGS ACROSS THE FA
WERE UPDATED INTO THE CURRENT FORECAST SCHEME...AND APPLIED TO THE
LATEST HOURLY RUC MODEL. THE RESULTS STILL KEEP THE SOUTHERNMOST
EXTENT OF THE SFC 32 DEGREE TEMP ISOTHERM AND LOW 30S DEWPOINTS
OCCURRING BETWEEN 4AM-8AM WED. AT 1ST LOOK...THE LATEST 00Z MODEL
DATA GUIDANCE INDICATES THAT SFC DEWPOINTS ARE PROGGED NOT TO DROP
INTO THE 20S BUT STAY AT 30 DEGREES OR HIGHER IN THE ADVISORY
AREA. THIS IS NOT ENOUGH TO FORCE A CHANGE IN THE CONFIGURATION OF
THE FREEZING RAIN ADV AT THIS TIME. BUT...IF ADDITIONAL 00Z
MODELS INDICATE A MILDER ATM PROFILE OR COLUMN IN THE LOWER
LEVELS...THEN A CHANGE WOULD LIKELY BE DEEMED NECESSARY.
ON A SIDE NOTE...THE 21Z SREF MODEL DATA CONTINUES TO ILLUSTRATE
THAT BLADEN AND/OR ROBESON COUNTIES HAVE THE HIGHEST PROBABILITY
TO OBSERVE MEASURABLE FREEZING RAIN WITHIN THE ILM CWA DURING THIS
EVENT.
DUE TO MORE OF A STRATUS TYPE EVENT...THE LATEST QPF ACROSS THE FA
WAS LOWERED TO ROUGHLY BETWEEN 0.1 TO 0.5 INCHES. HOWEVER...STILL
LOOKING AT SEVERAL ONE-HUNDREDTHS OF AN INCH TO LESS THAN ONE TENTH
OF AN INCH OF TOTAL ICE ACCUMULATION POSSIBLE WITHIN THE FREEZING
RAIN ADVISORY AREA. THEREFORE...THE CURRENT WWA LOOKS AOK WITH NO
NEEDED UPDATES FOR RE-CONFIGURATION.
PREVIOUS DISCUSSION....................................
AS OF 3 PM TUESDAY...A VERY LIGHT FREEZING RAIN SETUP STILL
APPEARS TO TAKE SHAPE TOWARDS THE VERY END OF THE PERIOD BUT SOME
NAGGING UNCERTAINTIES REMAIN. HIGH PRESSURE WILL PROGRESS EAST
TONIGHT MOVING FROM GREAT LAKES TO NEW ENGLAND STATES, WITH RIDGE
AXIS DEVELOPING INTO THE CAROLINAS. RIGHT AWAY THIS LEADS TO THE
FIRST FORECAST UNCERTAINTY AND THAT IS HOW COOL AND DRY THIS
AIRMASS BECOMES LOCALLY BY DAYBREAK WEDNESDAY AS THE CORE OF THE
AIRMASS REMAINS WELL TO OUR NORTH AND DEWPOINTS SEEMINGLY THE
LIMITING FACTOR. NOT PRESENT ARE THE VERY LOW DEWPOINTS OFTEN
ASSOCIATED WITH ARCTIC AIR AND FREEZING RAIN EVENTS, THE FORMER
SERVING AS A CONSTANT SOURCE OF LOWER DEWPOINTS AND THUS WETBULBS
TO SUPPORT THE LATTER. RATHER OVERNIGHT DEWPOINTS JUST A FEW
DEGREES F LAZILY OOZE INTO FAR NORTHWESTERN ZONES FOR A SETUP
ABOUT AS MARGINAL AS CAN BE. THE STRENGTH AND DEPTH OF THE WARM
NOSE (MAXING OUT AT 8-9C AT A HEIGHT OF 3500FT WITHIN AN ABOVE-
FREEZING LAYER SPANNING 2000FT- 9000FT) WILL PRECLUDE ANY PTYPES
OTHER THAN RAIN AND FREEZING RAIN. ANOTHER POINT OF UNCERTAINTY IS
MODEL QPF. BOTH GFS AND WRF SHOWING ALMOST AS MUCH AS 0.25 OVER
PART OF THE AREA BUT GIVEN OVERALL WEAK FORCING AND DRY MID AND
UPPER LEVELS THIS MAY BE HARD TO COME BY. THIS IDEA SUPPORTED BY
THE LATEST/15Z SREF WHICH SHOWS PROBS OF .25" STRUGGLING TO MAX
OUT AT 50 PERCENT OVER A SMALL PART OF THE REGION. LASTLY THE AREA
MOST FAVORED FOR FZRA MAY BORDER WHERE THE HIGHEST PRECIP OCCURS
AND ANY TINY ADJUSTMENT OF THAT BATTLE LINE COULD HAVE BIG
IMPLICATIONS FOR THE FORECAST. TOP-DOWN METHODOLOGY WITH A SLIGHT
HAT TIP TO THE SREF PTYPE ALGORITHM ACTUALLY CALLED FOR NO CHANGES
TO THE CURRENT ADVISORY WHERE SEEMINGLY UP TO JUST A FEW HUNDREDTH
OF AN INCH TO AT WORST ABOUT A TENTH OF AN INCH OF FREEZING RAIN
MAY OCCUR. WITH THE COOL AIR SO SLOW TO ARRIVE DO NOT EXPECT ANY
APPRECIABLE SUB-FREEZING TEMPS TIL 09Z. NON- ELEVATED SURFACES
LIKELY ABOVE FREEZING AND WILL HAVE TROUBLE ACCRETING MUCH ICE AT
ALL. THERE WAS SEEMINGLY LITTLE VALUE OR INCENTIVE TO TRIM THE
ADVISORY AS ITS IT QUITE UNDESIRABLE TO HAVE TO RE-RAISE ONE BUT
DO SUSPECT THAT EVENING SHIFT MAY BE ABLE TO REMOVE A SMALL PART
OF THE SOUTHERN PERIPHERY OF THE ADVISORY...ROUGHLY LINING UP WITH
WPC`S 40-50% LINE OF 0.01" OR MORE OF FZRA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...EARLY WEDNESDAY LINGERING ICE/-FZRA COULD
POSE COMMUTE HAZARDS BUT BY MIDDAY...DESPITE A COLD DAY
OVERALL...MELTING OF ANY ICE IS ANTICIPATED AS TEMPERATURES RISE
ABOVE FREEZING. THE PROBABILITY OF PCPN WILL WANE FROM SW TO NE
ACROSS NE SC AND SE NC THROUGH MORNING...LIKELY ENDING AS PATCHY
BUT CHILLY LIGHT RAIN OVER SE NC APPROACHING AFTERNOON. NO CHANGES
TO ENDING TIME OR THE GEOGRAPHY OF THE FZRA ADVISORY ON
WEDNESDAY...AND NOON EXPIRATION WAS RETAINED.
DRYING TREND THURSDAY AS WEAK HIGH SETS IN ACCOMPANIED BY MID-LVL
SUBSIDENCE. THE PROGRESSIVE PATTERN USHERS APPROACH OF AN UPPER
TROUGH LATE THURSDAY...HELPING TO LIFT AN IMPULSE OUT OF THE
NORTHERN GULF OF MEXICO LATE THU/EARLY FRI AND A SLIGHT CHANCE OF
PCPN. DURING THE PEAK OF MOISTURE LATE THU/EARLY FRI...TEMPS AT
THIS TIME APPEAR TO WARM TO SUPPORT FROZEN PCPN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...A DEEP LONG-WAVE TROUGH WILL BE EAST OF THE
FORECAST AREA BY THE START OF THE PERIOD. HIGH PRESSURE...SURFACE
AND ALOFT...WILL MOVE INTO THE EASTERN CAROLINAS FROM THE WEST ON
FRI. A LARGE N-S RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS THE AREA
ON SAT...MOVING OFFSHORE SAT NIGHT AND SUN. STILL SOME UNCERTAINTY
WITH REGARDS TO THE DEVELOPMENT OF A COASTAL TROUGH AND A WAVE OF
LOW PRESSURE MOVING UP THE COAST LATE IN THE WEEKEND. IF THIS TROUGH
DOES DEVELOP...THERE MAY BE A PERIOD OF SHOWERS ALONG THE COAST AND
OFFSHORE SUN. A COLD FRONT WILL SWEEP ACROSS THE AREA SUN NIGHT/
EARLY MONDAY. STILL UNCLEAR GIVEN MODEL SPREAD WHETHER ANY SHOWERS
WILL ACCOMPANY THE COLD FRONT. COOL HIGH PRESSURE WILL BUILD DOWN
THE EAST COAST ON TUE.
THE FORECAST PERIOD WILL LARGELY BE DRY...AND AT THIS TIME...NO
RAINFALL IS FORECAST EXCEPT FOR POSSIBLY THE IMMEDIATE COAST LATER
IN THE WEEKEND. A GOOD DEAL OF SUNSHINE WILL HELP TO FINALLY BRING
ABOVE NORMAL TEMPS TO THE REGION. TEMPS WILL WARM EACH DAY WITH SUN
BEING THE WARMEST...UPPER 50S AND LOWER 60S. TEMPS WILL THEN FALL
BACK MON AND TUE OF NEXT WEEK...BUT NO COOLER THAN NORMAL FOR MID
JANUARY. LOWS FRI NIGHT MAY DIP BELOW FREEZING INLAND LATE...
OTHERWISE WE DO NOT EXPECT FREEZING TEMPS OVER THE WEEKEND.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...IFR/LIFR IS OCCURRING EARLY THIS MORNING WITH LIGHT
RAIN/DRIZZLE/BR. AT KLBT CIGS ARE HOVERING AROUND 1K. THE RAIN IS
CURRENTLY ABATING...BUT SATELLITE IMAGES SHOW AN UPPER IMPULSE
APPROACHING FROM THE WEST. LIGHT DRIZZLE AND/OR LIGHT RAIN WILL
CONTINUE TO BE LIKELY THROUGH SUNRISE. WITH COLD AIR ADVECTION
TEMPERATURES WILL FALL TO NEAR FREEZING AT KLBT 09-10Z. LIGHT
FREEZING DRIZZLE AND/OR POSSIBLY LIGHT FREEZING RAIN WILL BE
POSSIBLE AT KLBT...ESPECIALLY ON ELEVATED SURFACES...UNTIL THE
TEMPERATURE WARMS ABOVE FREEZING AROUND 13Z.
PRECIPITATION SHOULD SHORTLY AFTER SUNRISE. IFR/LIFR CIGS WILL
SLOWLY LIFT DURING THE DAY. HIGH PRESSURE BUILDING IN SHOULD ALLOW
FOR CIGS TO LIFT TO MVFR AT KFLO/KLBT IN THE LATE MORNING/EARLY
AFTERNOON. CIGS AT KCRE/KMYR SHOULD ALSO REACH TEMPO MVFR LEVELS IN
THE EARLY AFTERNOON. AT KILM NEAREST THE OFFSHORE LOW IFR CIGS
APPEAR MOST LIKELY TO PERSIST INTO THE AFTERNOON.
EXTENDED OUTLOOK...MVFR/IFR CIGS WILL PREVAIL THROUGH THU MORNING AS
A COLD WEDGE OF HIGH PRESSURE REMAINS IN PLACE. VFR THU AFTN-SUN.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 AM WEDNESDAY...SMALL CRAFT ADVISORY REMAINS IN EFFECT.
FORECAST REMAINS UNCHANGED FOR THE EARLY MORNING HOURS. PREVIOUS
DISCUSSIONS FOLLOW:
CURRENT/LATEST WINDS AND SIGNIFICANT SEAS CONDITIONS REPORTED
ACROSS THE LOCAL WATERS...AND JUST OFFSHORE IE. FRYING PAN SHOALS
BUOY...ARE RUNNING SLIGHTLY HIGHER THAN THE LATEST WAVEWATCH 3
WIND AND SEAS FCST. AS A RESULT...THE OVERNIGHT WIND AND SEAS FCST
WAS TWEAKED GIVEN THESE LATEST TRENDS. THIS KEEPS THE ILM WATERS
WITHIN A STRONG SCA OVERNIGHT. ONCE THE LOW BEGINS ITS
AMPLIFICATION/INTENSIFICATION OFFSHORE AND ENE OF CAPE FEAR...WIND
DIRECTIONS WILL BACK FROM NE TO NNE OR DUE N...AT SPEEDS OF 20 TO
25 KT WITH G30 KT. THIS BACKING WILL HELP CUT DOWN SIGNIFICANT
SEAS ESPECIALLY NEARSHORE GIVEN THE REDUCED FETCH FOR WHICH TO
BUILD SEAS ACROSS THE ILM LOCAL WATERS. MUCH OF THIS BACKING WILL
LIKELY OCCUR AFTER THIS NEAR TERM PERIOD. AS A RESULT...HAVE
TWEAKED SIGNIFICANT SEAS A FOOT TO POSSIBLY 2 HIGHER DURING THE
OVERNIGHT PERIOD. AVERAGE PERIODS WILL RUN 4.0 TO 5.0 SECONDS.
PREVIOUS DISCUSSION............................
AS OF 3 PM TUESDAY...FRYING PAN SHOALS BUOY ALREADY UP TO 9 FT
DESPITE WINDS HAVING PRETTY MUCH LEVELED OFF. DOMINANT PERIOD OF 8
SECONDS SUGGESTING THAT NORTHEASTERLY SWELL ENERGY TEAMING UP WITH
THE AGITATED WINDS TO BLAME. THE PINCHED GRADIENT AND FETCH WILL NOT
CHANGE MUCH THROUGH THE PERIOD AND A SMALL INCREASE IN SEAS WILL
LARGELY OCCUR OUTSIDE OF THE FORECAST ZONES IN THE LARGELY
COAST-PARALLEL FLOW. SOLID SMALL CRAFT ADVISORY THUS CONTINUES
THROUGH THE PERIOD AND BEYOND. LOW PRESSURE DEVELOPS WELL OFF THE
COAST LATE IN THE PERIOD AND IT MAY ADD A FEW KTS OF WIND BUT THE
OVERALL POOR ALIGNMENT OF FLOW IN THE VERTICAL, OR EVEN THE LACK OF
MUCH WIND ABOVE THE SURFACE LAYER AT ALL FOR THAT MATTER, SHOULD
PRECLUDE GALES.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...UNFRIENDLY MARINE ENVIRONMENT TO KICK OFF WED
WITH LINGERING SEA-HEIGHTS OF 5-7 FEET AWAY FROM SHORE. AS WINDS
BECOME NW AND AND ABATE MORE IN EARNEST...ADVISORIES WILL LIKELY
BE DROPPED SOMETIME LATE THURSDAY NIGHT AS A COASTAL LOW PULLS
AWAY FROM THE 0-20 NM WATERS...AND SEA HEIGHT DAMPEN. NW WINDS
WILL HOLD THROUGH FRIDAY AS HIGH PRESSURE EDGES IN FROM THE WEST
BUT BELOW ADVISORY LEVELS. MODERATE N AND NW CHOP WILL EASE FRIDAY
ACCOMPANIED BY E WAVE 2-3 FEET RUNNING IN 9-10 SECONDS INTERVALS.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...HIGH PRESSURE WILL PUSH EASTWARD AND ACROSS
THE WATERS FRI WITH A LARGE RIDGE OF HIGH PRESSURE EXTENDING
ACROSS THE WATERS SAT. THIS RIDGE WILL THEN PULL OFFSHORE SAT
NIGHT AND SUN WITH A COASTAL TROUGH POSSIBLY DEVELOPING IN ITS
WAKE. CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA
DURING THIS PERIOD. WIND SPEEDS WILL BE UP TO 15 TO 20 KT
FRI...OTHERWISE 10 TO 15 KT OR LESS. SEAS WILL BE 3 TO 5 FT
FRI...OTHERWISE 2 TO 4 FT THROUGH THE WEEKEND. THE WIND DIRECTION
WILL BE N FRI...VEERING TO NE FRI NIGHT...E TO SE SAT...AND S TO
SW ON SUN AS HIGH PRESSURE MOVES PROGRESSIVELY OFFSHORE. LOW
PRESSURE MAY DEVELOP ON THE TROUGH LATE SAT AND IF THE LOW DOES
DEVELOP...A TIGHTER PRESSURE GRADIENT WILL BE REALIZED...RESULTING
IN HIGHER WINDS AND POSSIBLY SEAS BY THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR SCZ017-023-024-
032-033-053.
NC...FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR NCZ087-096-099-
105.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ250-252-
254-256.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/REK/MBB
SHORT TERM...MJC
LONG TERM...RJD
AVIATION...MRR
MARINE...DCH/REK/RJD/MBB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1146 PM EST TUE JAN 13 2015
.SYNOPSIS...
FREEZING LIGHT RAIN AND PATCHY ICY SURFACES ARE POSSIBLE LATE
TONIGHT AND EARLY WEDNESDAY FOR PARTS OF INTERIOR SOUTHEAST NORTH
CAROLINA AND NORTHEAST SOUTH CAROLINA. DESPITE A COLD DAY ON
WEDNESDAY...A SLOW WARMING SHOULD MELT ANY ICE THAT FORMS BY LATE
MORNING. WEAK HIGH PRESSURE WILL BRING A DRYING TREND THURSDAY.
A GULF OF MEXICO DISTURBANCE COULD BRING PATCHY LIGHT RAIN EARLY
ON FRIDAY. FAIR AND MILDER CONDITIONS ARE EXPECTED THIS WEEKEND
BEFORE A COLD FRONT MOVES THROUGH SUNDAY NIGHT. BUILDING HIGH
PRESSURE FROM THE NORTH WILL BRING A COOLING TREND EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 1115 PM TUESDAY...CONTINUED WITH NO CHANGES NEEDED FOR THE
CURRENT WINTER WX ADVISORY IN EFFECT FOR MUCH OF THE INLAND
PORTIONS OF THE ILM CWA.
THE FA IS STILL LOOKING AT A STRATUS TYPE LIGHT PCPN EVENT...WITH
THE POSSIBILITY OF FREEZING RAIN AND/OR DRIZZLE OCCURRING...IF
ENOUGH COLD AIR GETS FUNNELED SOUTHWARD BEFORE THE PCPN EVENT ENDS
COME MID TO LATE WED MORNING.
ONCE AGAIN...THE LATEST SFC TEMP/DEWPT READINGS ACROSS THE FA
WERE UPDATED INTO THE CURRENT FORECAST SCHEME...AND APPLIED TO THE
LATEST HOURLY RUC MODEL. THE RESULTS STILL KEEP THE SOUTHERNMOST
EXTENT OF THE SFC 32 DEGREE TEMP ISOTHERM AND LOW 30S DEWPOINTS
OCCURRING BETWEEN 4AM-8AM WED. AT 1ST LOOK...THE LATEST 00Z MODEL
DATA GUIDANCE INDICATES THAT SFC DEWPOINTS ARE PROGGED NOT TO DROP
INTO THE 20S BUT STAY AT 30 DEGREES OR HIGHER IN THE ADVISORY
AREA. THIS IS NOT ENOUGH TO FORCE A CHANGE IN THE CONFIGURATION OF
THE FREEZING RAIN ADV AT THIS TIME. BUT...IF ADDITIONAL 00Z
MODELS INDICATE A MILDER ATM PROFILE OR COLUMN IN THE LOWER
LEVELS...THEN A CHANGE WOULD LIKELY BE DEEMED NECESSARY.
ON A SIDE NOTE...THE 21Z SREF MODEL DATA CONTINUES TO ILLUSTRATE
THAT BLADEN AND/OR ROBESON COUNTIES HAVE THE HIGHEST PROBABILITY
TO OBSERVE MEASURABLE FREEZING RAIN WITHIN THE ILM CWA DURING THIS
EVENT.
DUE TO MORE OF A STRATUS TYPE EVENT...THE LATEST QPF ACROSS THE FA
WAS LOWERED TO ROUGHLY BETWEEN 0.1 TO 0.5 INCHES. HOWEVER...STILL
LOOKING AT SEVERAL ONE-HUNDREDTHS OF AN INCH TO LESS THAN ONE TENTH
OF AN INCH OF TOTAL ICE ACCUMULATION POSSIBLE WITHIN THE FREEZING
RAIN ADVISORY AREA. THEREFORE...THE CURRENT WWA LOOKS AOK WITH NO
NEEDED UPDATES FOR RE-CONFIGURATION.
PREVIOUS DISCUSSION................................................
AS OF 3 PM TUESDAY...A VERY LIGHT FREEZING RAIN SETUP STILL
APPEARS TO TAKE SHAPE TOWARDS THE VERY END OF THE PERIOD BUT SOME
NAGGING UNCERTAINTIES REMAIN. HIGH PRESSURE WILL PROGRESS EAST
TONIGHT MOVING FROM GREAT LAKES TO NEW ENGLAND STATES, WITH RIDGE
AXIS DEVELOPING INTO THE CAROLINAS. RIGHT AWAY THIS LEADS TO THE
FIRST FORECAST UNCERTAINTY AND THAT IS HOW COOL AND DRY THIS
AIRMASS BECOMES LOCALLY BY DAYBREAK WEDNESDAY AS THE CORE OF THE
AIRMASS REMAINS WELL TO OUR NORTH AND DEWPOINTS SEEMINGLY THE
LIMITING FACTOR. NOT PRESENT ARE THE VERY LOW DEWPOINTS OFTEN
ASSOCIATED WITH ARCTIC AIR AND FREEZING RAIN EVENTS, THE FORMER
SERVING AS A CONSTANT SOURCE OF LOWER DEWPOINTS AND THUS WETBULBS
TO SUPPORT THE LATTER. RATHER OVERNIGHT DEWPOINTS JUST A FEW
DEGREES F LAZILY OOZE INTO FAR NORTHWESTERN ZONES FOR A SETUP
ABOUT AS MARGINAL AS CAN BE. THE STRENGTH AND DEPTH OF THE WARM
NOSE (MAXING OUT AT 8-9C AT A HEIGHT OF 3500FT WITHIN AN ABOVE-
FREEZING LAYER SPANNING 2000FT- 9000FT) WILL PRECLUDE ANY PTYPES
OTHER THAN RAIN AND FREEZING RAIN. ANOTHER POINT OF UNCERTAINTY IS
MODEL QPF. BOTH GFS AND WRF SHOWING ALMOST AS MUCH AS 0.25 OVER
PART OF THE AREA BUT GIVEN OVERALL WEAK FORCING AND DRY MID AND
UPPER LEVELS THIS MAY BE HARD TO COME BY. THIS IDEA SUPPORTED BY
THE LATEST/15Z SREF WHICH SHOWS PROBS OF .25" STRUGGLING TO MAX
OUT AT 50 PERCENT OVER A SMALL PART OF THE REGION. LASTLY THE AREA
MOST FAVORED FOR FZRA MAY BORDER WHERE THE HIGHEST PRECIP OCCURS
AND ANY TINY ADJUSTMENT OF THAT BATTLE LINE COULD HAVE BIG
IMPLICATIONS FOR THE FORECAST. TOP-DOWN METHODOLOGY WITH A SLIGHT
HAT TIP TO THE SREF PTYPE ALGORITHM ACTUALLY CALLED FOR NO CHANGES
TO THE CURRENT ADVISORY WHERE SEEMINGLY UP TO JUST A FEW HUNDREDTH
OF AN INCH TO AT WORST ABOUT A TENTH OF AN INCH OF FREEZING RAIN
MAY OCCUR. WITH THE COOL AIR SO SLOW TO ARRIVE DO NOT EXPECT ANY
APPRECIABLE SUB-FREEZING TEMPS TIL 09Z. NON- ELEVATED SURFACES
LIKELY ABOVE FREEZING AND WILL HAVE TROUBLE ACCRETING MUCH ICE AT
ALL. THERE WAS SEEMINGLY LITTLE VALUE OR INCENTIVE TO TRIM THE
ADVISORY AS ITS IT QUITE UNDESIRABLE TO HAVE TO RE-RAISE ONE BUT
DO SUSPECT THAT EVENING SHIFT MAY BE ABLE TO REMOVE A SMALL PART
OF THE SOUTHERN PERIPHERY OF THE ADVISORY...ROUGHLY LINING UP WITH
WPC`S 40-50% LINE OF 0.01" OR MORE OF FZRA.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...EARLY WEDNESDAY LINGERING ICE/-FZRA COULD
POSE COMMUTE HAZARDS BUT BY MIDDAY...DESPITE A COLD DAY
OVERALL...MELTING OF ANY ICE IS ANTICIPATED AS TEMPERATURES RISE
ABOVE FREEZING. THE PROBABILITY OF PCPN WILL WANE FROM SW TO NE
ACROSS NE SC AND SE NC THROUGH MORNING...LIKELY ENDING AS PATCHY
BUT CHILLY LIGHT RAIN OVER SE NC APPROACHING AFTERNOON. NO CHANGES
TO ENDING TIME OR THE GEOGRAPHY OF THE FZRA ADVISORY ON
WEDNESDAY...AND NOON EXPIRATION WAS RETAINED.
DRYING TREND THURSDAY AS WEAK HIGH SETS IN ACCOMPANIED BY MID-LVL
SUBSIDENCE. THE PROGRESSIVE PATTERN USHERS APPROACH OF AN UPPER
TROUGH LATE THURSDAY...HELPING TO LIFT AN IMPULSE OUT OF THE
NORTHERN GULF OF MEXICO LATE THU/EARLY FRI AND A SLIGHT CHANCE OF
PCPN. DURING THE PEAK OF MOISTURE LATE THU/EARLY FRI...TEMPS AT
THIS TIME APPEAR TO WARM TO SUPPORT FROZEN PCPN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...A DEEP LONG-WAVE TROUGH WILL BE EAST OF THE
FORECAST AREA BY THE START OF THE PERIOD. HIGH PRESSURE...SURFACE
AND ALOFT...WILL MOVE INTO THE EASTERN CAROLINAS FROM THE WEST ON
FRI. A LARGE N-S RIDGE OF HIGH PRESSURE WILL EXTEND ACROSS THE AREA
ON SAT...MOVING OFFSHORE SAT NIGHT AND SUN. STILL SOME UNCERTAINTY
WITH REGARDS TO THE DEVELOPMENT OF A COASTAL TROUGH AND A WAVE OF
LOW PRESSURE MOVING UP THE COAST LATE IN THE WEEKEND. IF THIS TROUGH
DOES DEVELOP...THERE MAY BE A PERIOD OF SHOWERS ALONG THE COAST AND
OFFSHORE SUN. A COLD FRONT WILL SWEEP ACROSS THE AREA SUN NIGHT/
EARLY MONDAY. STILL UNCLEAR GIVEN MODEL SPREAD WHETHER ANY SHOWERS
WILL ACCOMPANY THE COLD FRONT. COOL HIGH PRESSURE WILL BUILD DOWN
THE EAST COAST ON TUE.
THE FORECAST PERIOD WILL LARGELY BE DRY...AND AT THIS TIME...NO
RAINFALL IS FORECAST EXCEPT FOR POSSIBLY THE IMMEDIATE COAST LATER
IN THE WEEKEND. A GOOD DEAL OF SUNSHINE WILL HELP TO FINALLY BRING
ABOVE NORMAL TEMPS TO THE REGION. TEMPS WILL WARM EACH DAY WITH SUN
BEING THE WARMEST...UPPER 50S AND LOWER 60S. TEMPS WILL THEN FALL
BACK MON AND TUE OF NEXT WEEK...BUT NO COOLER THAN NORMAL FOR MID
JANUARY. LOWS FRI NIGHT MAY DIP BELOW FREEZING INLAND LATE...
OTHERWISE WE DO NOT EXPECT FREEZING TEMPS OVER THE WEEKEND.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 00Z...MOSTLY IFR CIGS ARE OCCURRING THIS EVENING WITH LIGHT
RAIN BREAKING OUT FROM KFLO/KLBT. OCCASIONALLY CIGS ARE LOW MVFR AT
KLBT/KFLO. TEMPO MVFR CIGS SHOULD BECOME LESS LIKELY AS THE LOW
LEVELS BECOME MORE SATURATED FROM LIGHT RAIN/DRIZZLE THROUGH THE
OVERNIGHT HOURS. WITH COLD AIR ADVECTION TEMPERATURES WILL REACH
FREEZING AT KLBT 09-10Z. LIGHT FREEZING RAIN OR DRIZZLE/MAYBE FROZEN
PRECIPITATION WILL BE POSSIBLE ESPECIALLY ON ELEVATED SURFACES UNTIL
THE TEMPERATURE WARMS ABOVE FREEZING AROUND 13Z.
PRECIPITATION SHOULD END AROUND SUNRISE. IFR/LIFR CIGS WILL SLOWLY
LIFT WEDNESDAY. HIGH PRESSURE BUILDING IN AT KFLO/KLBT SHOULD
ALLOW CIGS TO IMPROVE TO MVFR IN THE LATE MORNING AFTERNOON. CIGS
AT KCRE/KMYR SHOULD ALSO REACH TEMPO MVFR LEVELS IN THE AFTERNOON.
AT KILM NEAREST THE OFFSHORE LOW IFR CIGS APPEAR MOST LIKELY TO
PERSIST INTO THE AFTERNOON.
EXTENDED OUTLOOK...MVFR/IFR CIGS WILL PREVAIL THROUGH THU MORNING AS
A COLD WEDGE OF HIGH PRESSURE REMAINS IN PLACE. VFR THU AFTN-SUN.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 PM TUESDAY...CURRENT/LATEST WINDS AND SIGNIFICANT SEAS
CONDITIONS REPORTED ACROSS THE LOCAL WATERS...AND JUST OFFSHORE
IE. FRYING PAN SHOALS BUOY...ARE RUNNING SLIGHTLY HIGHER THAN THE
LATEST WAVEWATCH 3 WIND AND SEAS FCST. AS A RESULT...THE OVERNIGHT
WIND AND SEAS FCST WAS TWEAKED GIVEN THESE LATEST TRENDS. THIS
KEEPS THE ILM WATERS WITHIN A STRONG SCA OVERNIGHT. ONCE THE LOW
BEGINS ITS AMPLIFICATION/INTENSIFICATION OFFSHORE AND ENE OF CAPE
FEAR...WIND DIRECTIONS WILL BACK FROM NE TO NNE OR DUE N...AT
SPEEDS OF 20 TO 25 KT WITH G30 KT. THIS BACKING WILL HELP CUT DOWN
SIGNIFICANT SEAS ESPECIALLY NEARSHORE GIVEN THE REDUCED FETCH FOR
WHICH TO BUILD SEAS ACROSS THE ILM LOCAL WATERS. MUCH OF THIS
BACKING WILL LIKELY OCCUR AFTER THIS NEAR TERM PERIOD. AS A
RESULT...HAVE TWEAKED SIGNIFICANT SEAS A FOOT TO POSSIBLY 2 HIER
DURING THE OVERNITE PERIOD. AVERAGE PERIODS WILL RUN 4.0 TO 5.0
SECONDS.
PREVIOUS DISCUSSION.....................................
AS OF 3 PM TUESDAY...FRYING PAN SHOALS BUOY ALREADY UP TO 9 FT
DESPITE WINDS HAVING PRETTY MUCH LEVELED OFF. DOMINANT PERIOD OF 8
SECONDS SUGGESTING THAT NORTHEASTERLY SWELL ENERGY TEAMING UP WITH
THE AGITATED WINDS TO BLAME. THE PINCHED GRADIENT AND FETCH WILL NOT
CHANGE MUCH THROUGH THE PERIOD AND A SMALL INCREASE IN SEAS WILL
LARGELY OCCUR OUTSIDE OF THE FORECAST ZONES IN THE LARGELY
COAST-PARALLEL FLOW. SOLID SMALL CRAFT ADVISORY THUS CONTINUES
THROUGH THE PERIOD AND BEYOND. LOW PRESSURE DEVELOPS WELL OFF THE
COAST LATE IN THE PERIOD AND IT MAY ADD A FEW KTS OF WIND BUT THE
OVERALL POOR ALIGNMENT OF FLOW IN THE VERTICAL, OR EVEN THE LACK OF
MUCH WIND ABOVE THE SURFACE LAYER AT ALL FOR THAT MATTER, SHOULD
PRECLUDE GALES.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...UNFRIENDLY MARINE ENVIRONMENT TO KICK OFF WED
WITH LINGERING SEA-HEIGHTS OF 5-7 FEET AWAY FROM SHORE. AS WINDS
BECOME NW AND AND ABATE MORE IN EARNEST...ADVISORIES WILL LIKELY
BE DROPPED SOMETIME LATE THURSDAY NIGHT AS A COASTAL LOW PULLS
AWAY FROM THE 0-20 NM WATERS...AND SEA HEIGHT DAMPEN. NW WINDS
WILL HOLD THROUGH FRIDAY AS HIGH PRESSURE EDGES IN FROM THE WEST
BUT BELOW ADVISORY LEVELS. MODERATE N AND NW CHOP WILL EASE FRIDAY
ACCOMPANIED BY E WAVE 2-3 FEET RUNNING IN 9-10 SECONDS INTERVALS.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...HIGH PRESSURE WILL PUSH EASTWARD AND ACROSS
THE WATERS FRI WITH A LARGE RIDGE OF HIGH PRESSURE EXTENDING
ACROSS THE WATERS SAT. THIS RIDGE WILL THEN PULL OFFSHORE SAT
NIGHT AND SUN WITH A COASTAL TROUGH POSSIBLY DEVELOPING IN ITS
WAKE. CONDITIONS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA
DURING THIS PERIOD. WIND SPEEDS WILL BE UP TO 15 TO 20 KT
FRI...OTHERWISE 10 TO 15 KT OR LESS. SEAS WILL BE 3 TO 5 FT
FRI...OTHERWISE 2 TO 4 FT THROUGH THE WEEKEND. THE WIND DIRECTION
WILL BE N FRI...VEERING TO NE FRI NIGHT...E TO SE SAT...AND S TO
SW ON SUN AS HIGH PRESSURE MOVES PROGRESSIVELY OFFSHORE. LOW
PRESSURE MAY DEVELOP ON THE TROUGH LATE SAT AND IF THE LOW DOES
DEVELOP...A TIGHTER PRESSURE GRADIENT WILL BE REALIZED...RESULTING
IN HIGHER WINDS AND POSSIBLY SEAS BY THE END OF THE PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY UNTIL NOON EST WEDNESDAY FOR SCZ017-023-
024-032-033-053.
NC...FREEZING RAIN ADVISORY UNTIL NOON EST WEDNESDAY FOR NCZ087-096-
099-105.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR
AMZ250-252-254-256.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/MBB
SHORT TERM...MJC
LONG TERM...RJD
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS TULSA OK
1152 PM CST TUE JAN 13 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
MID CLOUDS...CURRENTLY JUST WEST OF A BVO/TUL/MLC LINE WILL
SLOWLY SPREAD EAST OVERNIGHT INTO WEDNESDAY MORNING. STILL COULD
SEE AREAS OF LIGHT SNOW SPREAD ACROSS NORTHEAST OKLAHOMA INTO THE
DAY WEDNESDAY WITH A LIMITED/PROB30 CHANCE FOR MVFR CONDITIONS AT
BVO. OTHERWISE...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH
THE FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 938 PM CST TUE JAN 13 2015/
..UPDATE...
DISCUSSION...
UPDATED FORECAST THIS EVENING TO INCLUDE SOME LOW CHANCE POPS
ACROSS NORTHEAST OKLAHOMA LATE TONIGHT INTO THE DAY WEDNESDAY.
LOCAL WRF AND HRRR HINTING AT THE POTENTIAL FOR WIDELY SCATTERED
AREAS OF LIGHT SNOW/SLEET DURING THIS TIME. LATEST 00Z NAM ALSO
DEVELOPS SOME LIGHT PRECIP DURING THE DAY WEDNESDAY NORTH OF
INTERSTATE 44 AS MAIN UPPER LEVEL JET STREAK SHIFTS INTO THE
REGION. ANY SNOW ACCUMULATIONS WOULD BE LIGHT AND FAIRLY
LOCALIZED WITH NO WIDESPREAD IMPACTS. THIS WILL CONTINUE TO BE
MONITORED AS ADDITIONAL DATA BECOMES AVAILABLE.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...12
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
300 AM EST WED JAN 14 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE STRETCHED FROM THE MID MISSISSIPPI
VALLEY TO THE NEW ENGLAND STATES WILL MAINTAIN CONTROL OF OUR
LOCAL WEATHER THROUGH MUCH OF THURSDAY. A VIGOROUS UPPER LEVEL
DISTURBANCE AND ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST FROM THE
GREAT LAKES AND CROSS THE STATE THURSDAY NIGHT AND EARLY
FRIDAY. THIS RELATIVELY MOISTURE STARVED SYSTEM WILL BE ACCOMPANIED
BY SOME SNOW SHOWERS AND FOLLOWED BY ANOTHER SHOT OF COLDER AIR
FOR FRIDAY AND ON INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
HIGH CLOUDS CONTINUE TO SPREAD NORTH AND GRADUALLY THICKEN-UP
ACROSS THE SOUTHERN HALF OF PENN...WHILE MAINLY CLEAR SKIES ACROSS
THE NORTHERN MTNS HAVE ALLOWED TEMPS TO DROP TO FRIGID LEVELS OF
5-10 BELOW ZERO IN SOME RURAL VALLEY LOCATIONS OF ELK...MCKEAN AND
POTTER COUNTIES. SCHOOL/MESO OBS FROM THAT AREA SHOW A -14F INVOF
MT JEWETT IN SOUTHERN MCKEAN COUNTY...AND -11F IN THE CITY OF
BRADFORD.
TEMPS SHOULD FALL UP TO ANOTHER FEW DEG F ACROSS THE NRN
TIER...WHILE THE INCREASING CLOUDS FURTHER SOUTH LEVEL OFF THE
TEMPS.
THE SOUTHERN THIRD OF THE STATE SHOULD SEE TEMPS HOLDING STEADY IN
THE MID TO UPPER TEENS...OR FALL JUST A FEW DEG F UNDER THE
THICKEST CLOUD COVER.
WILL BE CLOSELY MONITORING THE PROGRESSION OF THE NRN EDGE OF
LIGHT SNOW MAKING IT/S WAY NNE ALONG THE I-95 CORRIDOR /AND NOW
OVERSPREADING THE D.C. AREA. 00Z HI RES ARW AND NMM...ALONG WITH
THE 07Z HRRR AND RAP PRECIP DEPICTION IS ALREADY TOO FAR SOUTH BY
NEARLY 50 NM /AND BARELY BRUSHES THE DC AREAS WITH ANY MEASURABLE
SNOW THIS MORNING/.
00Z 12KM NAM AND 03Z SREF ARE THE FURTHER NORTH WITH THE LEADING
EDGE OF THE LIGHT SNOW AND APPEAR TO BE MORE ON TARGET WITH ITS
PRESENT LOCATION. ANOMALOUS EASTERLY 925 MB FLOW SHOULD HELP TO
MAINTAIN SOME VERY LIGHT SNOW AS IT APPROACHES THE MASON DIXON
LINE AROUND OR SHORTLY AFTER DAYBREAK.
WILL MAKE JUST SOME MINOR ADJUSTMENTS TO THE ALREADY VERY LIGHT
QPF/SNOW FORECAST FOR OUR EXTREME SE CWA...NEAR AND TO THE SOUTH
OF STATE RT 30 FROM YORK TO LANCASTER.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM THURSDAY/...
RATHER THICK MID-LEVEL CLOUDS WILL LIKELY BE AFFECTING AT LEAST
THE SOUTHERN PORTION OF THE FORECAST AREA TO START THE DAY TODAY.
SOME LIGHT SNOW AND A DUSTING IS POSSIBLE TO THE SOUTH OF A KTHV
TO KLNS LINE LATE THIS MORNING AS THE AXIS OF STRONGEST EASTERLY
LLVL FLOW AND A FEW EAST/WEST BANDS OF WEAK 850-700 MB
FRONTOGENESIS AND UVVEL BRUSHES THAT AREA.
AS THE SFC LOW OFFSHORE STARTS TO BECOME BETTER ORGANIZED ALONG
THE FRONTAL ZONE...GEOSTROPHIC FLOW SHOULD TURN BACK MORE TO THE
NORTH ONCE AGAIN AND FORCE THE CLOUDS BACK OUT OF THE AREA FROM NW
TO SE.
IT WILL REMAIN COLD TODAY AND HIGHS IN THE 20S WILL BE WELL BELOW
NORMAL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A BROADENING LONGWAVE TROF OVER THE EASTERN HALF OF THE CONUS WILL
LEAD TO COLD AND GENERALLY DRY WEATHER ACROSS THE REGION THROUGH THE
REMAINDER OF THE WEEK. UPPER FLOW IS FORECAST TO BECOME ZONAL FOR
A SHORT PERIOD OVER THE WEEKEND BEFORE ANOTHER TROF REDEVELOPS
FROM THE OHIO VALLEY EASTWARD NEXT WEEK.
THE PATTERN THROUGH THIS WEEK SHOULD SEE SEVERAL WEAK AND MAINLY
DRY SHORTWAVES IN THE NRN STREAM THAT COULD BRING A SLIGHT CHANCE
OF LIGHT PCPN...MAINLY FRIDAY AFTN IN THE NW MTNS...AND LATE THIS
UPCOMING WEEKEND. CONSIDERING THE PHASE SHIFT AND INCONSISTENCIES
OF THE ENSEMBLES...HAVE LEFT ONLY CHANCE POPS. TEMPS SHOULD SEE A
GENERAL RISE AS THE WEEK CONTINUES INTO THE WEEKEND...WITH HIGHS
CLIMBING INTO THE 40S ALONG THE SOUTHERN TIER POSSIBLE BY LATE IN
THE WEEKEND.
THE RENEWED TROFFING WILL SEND TEMPS BACK DOWN NEXT WEEK...BUT
AT THIS POINT NOT LOOKING AS COLD AS THIS WEEK. CHANCES OF PCPN
REMAIN LOW FOR NEXT WEEK AS WELL WITH LITTLE TO NO ROOM FOR
AMPLIFICATION OF SHORTWAVE ENERGY.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
A WEAK SHORTWAVE LIFTING NEWD FROM THE TN VALLEY/CENTRAL
APPALACHIANS WILL CROSS THE SOUTHERN MID-ATLANTIC STATES EARLY
TODAY. THE ENERGY IS EXPECTED TO INVIGORATE AN AREA OF LOW
PRESSURE EAST OF THE NC OUTER BANKS WHICH IS THEN FORECAST TO
EXIT NORTHEAST WELL OFF THE EAST COAST. WHILE THE BULK OF THE
PRECIPITATION WITH THIS SYSTEM IS FORECAST TO REMAIN S/E OF THE
AIRSPACE...SOME LOWER CIGS ARE A GOOD BET...AT LEAST AOB 5KFT OVER
THE SOUTH-CENTRAL/SE TERMINALS. HIGHEST CONFIDENCE IN POTENTIAL
IFR CONDITIONS WOULD BE AT JST GIVEN UPSLOPE FLOW AND SUPPORT FROM
GUIDANCE. RESTRICTIONS ARE STILL A TOUGH CALL TOWARD THE SERN
AIRFIELDS MDT/LNS -- AND FOR NOW WILL GO WITH LOW VFR CIGS BLW
5KFT AND MONITOR CIG TRENDS TO THE SOUTH. CONFIDENCE IS EVEN LOWER
IN LIGHT SNOW POTENTIAL AS PRECIPITATION AREA CURRENTLY MOVG NWD
ACRS CENTRAL VA INTO SRN MD CONTINUES TO LIFT NEWD THIS MORNING.
OUTLOOK...
THU...VFR/NO SIG WX.
FRI...MVFR CIGS/-SHSN POSSIBLE N/W. VFR ELSEWHERE. NW WIND GUSTS
20-30KTS.
SAT..VFR/NO SIG WX.
SUN...IFR RESTRICTIONS POSSIBLE WITH CHANCE OF SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/LA CORTE
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
309 AM CST WED JAN 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CST WED JAN 14 2015
NOT A LOT GOING ON TODAY AND TONIGHT AS A NORTHWEST FLOW ALOFT
CONTINUES TO DOMINATE THE AREAS WEATHER. THE REMAINING STRATUS
ACROSS OUR FORECAST AREA EARLY THIS MORNING WILL EXIT...ONLY TO BE
REPLACED BY MID AND HIGH LEVEL CLOUDS MOVING IN FROM THE NORTHWEST.
BUT TODAY WILL MARK THE BEGINNING OF A WARMING TREND...WITH HIGHS
FINALLY CLOSER TO SEASONAL NORMALS WITH 20S ALONG AND EAST OF THE
JAMES RIVER VALLEY...AND LOWER 30S IN OUR SOUTH CENTRAL SD ZONES.
TONIGHT...A SURFACE TROUGH OF LOW PRESSURE WILL MOVE THROUGH. AHEAD
OF THE TROUGH...TEMPERATURES WILL LIKELY BE COOLER THAN READINGS
BEHIND THE TROUGH. THEREFORE TEMPERATURES MAY STEADY OUT OR EVEN
SLIGHTLY RISE AFTER MIDNIGHT FOR MANY LOCATIONS. BECAUSE OF THIS...
LOWS SHOULD BOTTOM OUT IN THE MID TEENS TO LOWER 20S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 308 AM CST WED JAN 14 2015
EXTENDED CONTINUES TO APPEAR RELATIVELY MILD FOR THIS TIME OF YEAR
WITH WEST TO NORTHWEST FLOW PREVAILING ACROSS THE PLAINS. WITH WEST
TO NORTHWEST FLOW PREVAILING...DO NOT THINK LOW LYING STRATUS WILL
BE AN ISSUE...BUT MODELS SUGGESTING THAT A FAIR AMOUNT OF MID AND
UPPER LEVEL CLOUDS WILL BE AROUND LATE THIS WEEK INTO THIS WEEKEND.
RAISED CLOUD COVER. MIXING TO 925 HPA ALONE WOULD SUGGEST WARMER
TEMPERATURES THAT THE CURRENT FORECAST...HOWEVER...WITH FAIRLY DEEP
SNOWCOVER UPSTREAM...WAS NOT OVERLY AGGRESSIVE IN RAISING
TEMPERATURES.
ON FRIDAY...MODELS SHOW WINDS INCREASING ACROSS THE EASTERN THIRD
AHEAD OF A TROUGH APPROACHING FROM THE WEST. WITH STRONG SOUTHWEST
FLOW ALOFT...SOUTHWEST MINNESOTA MAY BE ABLE TO WARM MORE THAN THEY
WOULD OTHERWISE.
SURFACE TROUGH PASSES TO THE NORTH OF THE FORECAST AREA FRIDAY
NIGHT. COLD FRONT MOVES THROUGH THE AREA LATE IN THE OVERNIGHT
PERIOD...WITH LITTLE IN THE WAY OF COLD AIR BEHIND THE FRONT.
HOWEVER...THE PRESSURE GRADIENT IS QUITE STRONG BEHIND THE FRONT
WITH 40-45 KNOTS AT 925 HPA PREVAILING THROUGH THE DAY ON SATURDAY.
HAVE INCREASED WINDS FAIRLY SUBSTANTIALLY DURING THE DAY ON
SATURDAY...AS IT LOOKS LIKE A SOLID WIND ADVISORY.
WINDS ARE SLOW TO SUBSIDE SATURDAY NIGHT...BUT WITH LACK OF COLD AIR
ADVECTION WAS UNSURE HOW LONG TO KEEP THEM STRONG. FOR NOW...SIDED
CLOSE TO CONS MOS NUMBERS THROUGH THE EVENING HOURS.
LOOKS LIKE A SLIGHT COOL DOWN ON SUNDAY INTO MONDAY BUT TEMPERATURES
STILL REMAIN ABOVE NORMAL. MODELS ARE IN REMARKABLY GOOD AGREEMENT
ON OPEN WAVE TRANSLATING FROM THE PACIFIC NORTHWEST EASTWARD INTO
THE PLAINS. THIS WAVE WOULD AFFECT THE FORECAST AREA MONDAY NIGHT
INTO TUESDAY. WITH GOOD AGREEMENT IN TERMS OF PLACEMENT AND
TIMING...INCREASED POPS OVER INITIAL GUIDANCE MONDAY NIGHT INTO
TUESDAY. PRECIPITATION TYPE WITH THIS SYSTEM COULD BE A LITTLE
TRICKY ACROSS THE SOUTHERN EDGE OF THE FORECAST AREA WITH
TEMPERATURES AT OR SLIGHTLY ABOVE FREEZING. FOR NOW...LEFT PRECIP
TYPE AS RAIN OR SNOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1044 PM CST TUE JAN 13 2015
AREA OF MVFR STRATUS WILL MOVE ACROSS THE AREA TONIGHT. USED THE
RAP AND HRRR FOR TIMING...AS BOTH MATCH CURRENT OBS PRETTY WELL.
EXPECT A RETURN TO VFR FROM NORTHWEST TO SOUTHEAST LATER TONIGHT
INTO THE MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1046 PM CST TUE JAN 13 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 332 PM CST TUE JAN 13 2015
LIFT ASSOCIATED WITH THE SHORT WAVE...SOME INSTABILITY ALOFT...AND
LIFT LARGELY IN THE DENDRITIC ZONE WILL CONTINUE TO TRIGGER SNOW
SHOWERS OVER THE NORTHERN COUNTIES LATE THIS AFTERNOON WITH ACTIVITY
PASSING INTO THE NORTHEAST AND EAST CENTRAL AREA...THAT IS SOUTHWEST
MN TO THE IA GREAT LAKES...THIS EVENING BEFORE PASSING EAST
SOUTHEAST OF THE AREA DURING THE NIGHT. VISIBILITIES HAVE LOWERED TO
AS LOW AS A QUARTER MILE THIS AFTERNOON AND THIS COULD CONTINUE FOR
SEVERAL HOURS. ACCUMULATIONS WILL BE LIMITED BY DURATION AND STILL
DO NOT EXPECT MORE THAN AN INCH ANYWHERE...THOUGH WE WILL HAVE TO
WATCH THE FAR NORTHEAST INCLUDING MARSHALL MN AREA AROUND SUNSET.
LITTLE OR NOTHING IS EXPECTED SOUTH OF INTERSTATE 90 EXCEPT PERHAPS
IN NORTHWEST IA DOWN TO SPENCER FOR THE EVENING.
AS THE WAVE PASSES...THE SEMI STIFF SOUTHERLY SURFACE FLOW WILL EASE
AND START TO TURN MORE WESTERLY TONIGHT. CLOUD COVER PRESENTS SOME
PROBLEMS WITH MODELS INDICATING SOME LOW LEVEL MOISTURE BANDS BEHIND
THE WAVE. ENOUGH CLEARING SHOULD OCCUR SO THAT WITH THE LIGHT
WINDS...WE WILL HAVE A LITTLE SURFACE TEMPERATURE DROP TONIGHT...
THOUGH OF COURSE LOWS WILL BE MUCH WARMER THAN THOSE LAST
NIGHT...MAINLY 5 TO 10 ABOVE ZERO EXCEPT 10 TO 15 SOUTHWEST. DO NOT
EXPECT ANY FOG...IT IS THE KIND OF PATTERN WHERE WE MIGHT EXPECT A
LITTLE AS THE WINDS GOT LIGHT IF WE HAD GOTTEN ABOVE FREEZING TODAY.
WEDNESDAY WILL BE UNEVENTFUL...WITH STILL SOME QUESTIONS ON CLOUD
COVER...BUT DO NOT EXPECT EITHER CLEAR OR SOLID OVERCAST.
TEMPERATURES LOOK IN LINE WITH WHAT WE HAVE BEEN GOING FOR WITH 20S
NORTH AND EAST TO LOWER 30S SOUTHWEST. WINDS WILL BE LIGHTER THAN
TODAY...PEAKING AT AROUND 10 MPH WITH SOME SORT OF WESTERLY
COMPONENT...AND IN VIEW OF RECENT COLD IT SHOULD FEEL PLEASANT FOR
ANYONE WHO DID NOT JUST FLY IN FROM FLORIDA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 332 PM CST TUE JAN 13 2015
PROLONGED PERIOD OF MUCH MILDER TEMPERATURES AND DRY WEATHER IS
EXPECTED THROUGH THE BULK MIDDLE AND LONG RANGE. PREDOMINATELY
NORTHWEST UPPER LEVEL FLOW WILL REIGN. WHILE A FEW WEAK SHORTWAVES
TRACK INTO THE NORTHERN PLAINS... WE ARE NOT EXPECTING ANY
PRECIPITATION THROUGH MONDAY.
THE FIRST WEAK SHORTWAVE DROPS ALONG THE NORTHWEST FLOW ON WEDNESDAY
NIGHT AND THURSDAY MORNING. MID AND HIGH CLOUDS WILL BLANKET THE
REGION WEDNESDAY EVENING THEN CLEAR OUT FROM WEST TO EAST OVERNIGHT.
925 MB TEMPERATURES WILL BE MILD AT AROUND 0 TO +3C THURSDAY
MORNING...BUT COOL SLIGHTLY THURSDAY AFTERNOON. WEST TO NORTHWEST
WINDS LOW LEVEL WINDS SHOULD MIX DOWN SOME MUCH WARMER TEMPERATURES
IN THE 30S...WITH THE LOWER 40S IN THE LOWER BRULE. A LITTLE MORE
UNCERTAINTY ARRIVES ON FRIDAY MORNING AS ANOTHER WEAK AND FAST
MOVING SHORTWAVE DIVES SOUTHEAST. MODELS VARY IN THE STRENGTH AND
TRACK OF THIS FEATURE...BUT ONLY IMPACT WILL BE SOME PASSING HIGH
CLOUDS. TEMPERATURES SHOULD REMAIN MILD WITH SIMILAR READINGS TO
THURSDAY.
BEHIND THE WAVE...WINDY CONDITIONS DEVELOP FRIDAY NIGHT AND
SATURDAY. MIXY CONDITIONS AND WARM LOW AND MID LEVELS WILL RESULT IN
EVEN MILDER TEMPERATURES ON SATURDAY. HIGHS WILL IMPROVE A FEW MORE
DEGREES IN OUR NORTHEAST...REACHING THE MID 30S TO LOWER 40S
AREAWIDE. A MORE SUBSTANTIAL TROUGH BREAKS DOWN THE RIDGE EARLY NEXT
WEEK. THIS LOOKS LIKE THE BEST SHOT FOR ANY PRECIPITATION DURING THE
FORECAST PERIOD...WITH THE BEST CHANCES MONDAY NIGHT INTO TUESDAY.
WILL GO WITH LOW END CHANCES OF SNOW FOR NOW...PERHAPS MIXING WITH
RAIN IN THE FAR SOUTH. TEMPERATURES REMAIN ABOVE NORMAL EARLY NEXT
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1044 PM CST TUE JAN 13 2015
AREA OF MVFR STRATUS WILL MOVE ACROSS THE AREA TONIGHT. USED THE
RAP AND HRRR FOR TIMING...AS BOTH MATCH CURRENT OBS PRETTY WELL.
EXPECT A RETURN TO VFR FROM NORTHWEST TO SOUTHEAST LATER TONIGHT
INTO THE MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1004 PM MST TUE JAN 13 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 233 PM MST TUE JAN 13 2015
WEATHER CONDITIONS WILL BE TRANSITIONING TO SLIGHTLY WARMER TEMPS AND
LESS LOW CLOUD COVER THROUGH WED. WATER VAPOR IMAGERY SHOWS AN
UPPER LOW SPINNING ACROSS NORTHERN ARIZONA WITH LARGE SCALE ASCENT
ACROSS SOUTHWESTERN COLORADO. LOW CLOUDS HAVE BEEN PERSISTENT OVER
MUCH OF THE CWA...HOWEVER BEGINNING TO SEE SOME RAISING CIGS AS
THE LLVLS ARE STARTING TO DRY. SFC PRESSURES ARE RISING AND A COLD
FRONT IS MOVING OVER THE SOUTHERN ZONES RIGHT NOW WITH CHEYENNE
GETTING NORTHERLY WIND GUSTS TO 30 MPH. LLVL RH PROGS AND
SOUNDINGS INDICATE THAT LOW CLOUDS WILL CONTINUE TO CLEAR THROUGH
THE EVENING AND EARLY NIGHT. ADDED SOME PATCHY FOG OVER PORTIONS
OF CARBON COUNTY AS WINDS ARE REALLY LIGHT AND RUC SOUNDINGS
SHOULD A GOOD LLVL INVERSION AND SATURATION. IT WILL BE ANOTHER
CHILLY NIGHT ESPECIALLY WITH CLEARING SKIES.
HEIGHTS ALOFT RISE ON WED WITH LIGHT WESTERLY SFC WINDS OVER MUCH
OF THE REGION. STARTING TO GET SOME WEAK PRESSURE FALLS TO THE
EAST OF THE LARAMIE RANGE HOWEVER THE CAG-CPR GRADIENT REMAINS
BELOW 30 METERS. TEMPS WILL MODERATE SOME COMPARED TO TODAY (5-10
DEGREES WARMER) HOWEVER THE PRONOUNCED DOWNSLOPING AND WARMING
WILL NOT ARRIVE UNTIL THURS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 233 PM MST TUE JAN 13 2015
WEDNESDAY NIGHT/THURSDAY...NORTH NORTHWEST FLOW ALOFT TRANSITIONS TO
NORTHWEST. MILD WEATHER ENTHUSIASTS WILL ENJOY THURSDAY AS DOWNSLOPE
WARMING AND A MODERATING AIRMASS HELPS HIGH TEMPERATURES TO SOAR
WELL INTO THE 40S AND LOWER 50S EAST OF I-25 AND 30S WEST OF I-25.
FRIDAY...FLOW ALOFT BACKS EVEN MORE TO WEST...INDUCING EVEN MORE
DOWNSLOPE WARMING AND WITH PROGGED THICKNESSES AND 700 MB
TEMPERATURES...WE EXPECT MAXIMUM TEMPERATURES TO SOAR WELL INTO THE
40S TO MID 50S AT LOWER ELEVATIONS ASSUMING MIDDLE AND HIGH CLOUD
OPACITY...THICKNESS...IS MINIMAL. OUR WIND PRONE LOCATIONS MAY BE
NEAR HIGH WIND CRITERIA BASED ON THE PROGGED LOW AND MID LEVEL
GRADIENTS.
SATURDAY...POTENT ALBERTA CLIPPER SHORTWAVE TROUGH ALOFT SWEEPS
ACROSS THE NORTHERN PLAINS STATES WITH THE ASSOCIATED COLD FRONT
SLIDING ACROSS OUR COUNTIES EARLY IN THE DAY...USHERING IN WINDY
CONDITIONS ALONG WITH HIGH TEMPERATURES BACK INTO THE 30S TO MID 40S
AT LOWER ELEVATIONS. COULD SEE A FEW LOCATIONS NEAR HIGH WIND
CRITERIA IN THE FEW HOURS AFTER COLD FRONTAL PASSAGE DUE TO A BORA
EVENT.
SUNDAY...THE ROLLER COASTER CONTINUES WITH THE FLOW ALOFT TURNING
WEST NORTHWEST...INDUCING MORE SURFACE LEE TROUGHING AND AIDING
WARMING TEMPERATURES INTO THE 40S AND LOWER 50S AT LOWER ELEVATIONS.
MONDAY...ANOTHER FAST MOVING SHORTWAVE TROUGH ALOFT SWEEPS ACROSS
THE NORTHERN ROCKIES SENDING ANOTHER COLD FRONT INTO OUR COUNTIES IN
THE AFTERNOON AND PRODUCING A COOLING TREND. WILL SEE SCATTERED
OROGRAPHIC SNOWS OVER THE SNOWY AND SIERRA MADRE RANGES...DRY
ELSEWHERE.
TUESDAY...WINDY AND COLD WITH A FEW MOUNTAIN SNOW SHOWERS...AS A
BROAD TROUGH ALOFT PREVAILS OVER THE NORTHERN PLAINS STATES SENDING
REINFORCING COLD AIR SOUTHWARD ACROSS OUR COUNTIES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1001 PM MST TUE JAN 13 2015
LATEST 11-3.9U SATELLITE IMAGERY SHOWING LOW CLOUDS FILLING IN
OVER CARBON COUNTY LATE THIS EVENING. DO BELIEVE THERE IS A CHANCE
FOR KRWL TO GO DOWN ONCE AGAIN OVERNIGHT IN NORTHEAST FLOW.
CONCERNS FOR KLAR AS WELL...BUT CONFIDENCE IS NOT THERE FOR THEM
TO GO DOWN AS THEY STAY IN A NORTHEAST DOWNSLOPE WIND FLOW.
ELSEWHERE...VFR CONDITIONS SHOULD PREVAIL.
&&
.FIRE WEATHER...
ISSUED AT 233 PM MST TUE JAN 13 2015
NO CRITICAL FIRE WEATHER CONDITIONS OVER THE NEXT FEW DAYS.
WIDESPREAD SNOW COVER REMAINS ON THE GROUND. TEMPERATURES WILL
WARM TO AROUND NORMAL BY THURSDAY...HOWEVER MINIMUM AFTERNOON
HUMIDITY VALUES WILL STILL BE ABOVE 30 PERCENT.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...RUBIN
AVIATION...GCC
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
324 AM MST WED JAN 14 2015
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 320 AM MST WED JAN 14 2015
NLY FLOW ALOFT WILL BE OVER THE AREA TODAY THRU TONIGHT. SOME
LINGERING LOW LVL MOISTURE WILL CONTINUE TO AFFECT THE HIGHER
TERRAIN AND ALONG THE FRONT RANGE THIS MORNING HOWEVER DO NOT EXPECT
ANY PCPN. ALSO THERE MAY BE SOME FOG IN THE HIGHER VALLEYS AND IN
THE FOOTHILLS WITH PATCHY AREAS OVER THE PLAINS. AS FOR HIGHS 850-
700 MB TEMPS RISE A DEGREE OR TWO FM TUE SO EXPECT HIGHS MAINLY IN
THE 30S OVER NERN CO.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 320 AM MST WED JAN 14 2015
MODELS HAVE AN UPPER RIDGE WITH WEAK ZONAL FLOW FOR THE CWA ON
THURSDAY. THERE IS A FLATTER UPPER RIDGE AROUND ON FRIDAY. AN
UPPER TROUGH MOVES ACROSS FRIDAY NIGHT. THE SYNOPTIC SCALE ENERGY
IS NEUTRAL TO WEAK DOWNWARD THURSDAY THROUGH FRIDAY NIGHT. THE
BOUNDARY LAYER FLOW THROUGH THE FOUR PERIODS IS MOSTLY DOWNSLOPING.
MOISTURE IS QUITE SPARSE THURSDAY THROUGH FRIDAY...WITH SOME
INCREASE FRIDAY NIGHT...MOSTLY OVER THE MOUNTAINS. THE QPF FIELDS
HAVE NO MEASURABLE PRECIPITATION OVER THE CWA THURSDAY THROUGH
FRIDAY...THEN A TAD OVER THE MOUNTAINS FRIDAY NIGHT. NO POPS
THROUGH FRIDAY EVENING...THEN A TAD IN THE MOUNTAINS OVERNIGHT. IT
IS PRETTY DRY. FOR TEMPERATURES...THURSDAY`S HIGHS ARE UP 3-7 C
FROM WEDNESDAY`S. FRIDAY`S HIGHS ARE UP ANOTHER 1.0-2.5 C FROM
THURSDAY`S. FOR THE LATER DAYS...SATURDAY THROUGH TUESDAY...THERE
IS NORTHWESTERLY FLOW ALOFT ON SATURDAY WITH AN UPPER RIDGE TO THE
WEST. THE RIDGE MOVES ACROSS COLORADO SUNDAY WITH ZONAL FLOW
SUNDAY AND MONDAY. THERE IS ANOTHER WEAK UPPER TROUGH MONDAY NIGHT
INTO TUESDAY. THE MOISTURE IS NOT GREAT WITH THE TROUGH. A COLD
FRONT MOVES IN TUESDAY. NOT MUCH IN THE WAY OF POPS...AND ONLY FOR
THE MOUNTAINS...NOTHING FOR THE PLAINS. TEMPERATURES WILL BE ABOVE
SEASONAL NORMALS SUNDAY AND MONDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 320 AM MST WED JAN 14 2015
CEILINGS IN THE 3000-3500 FT RANGE CONTINUE EARLY THIS MORNING.
BASED ON STRATUS BREAKOUT PROGRAM THEY MAY LINGER THRU ABOUT 14Z.
MEANWHILE LATEST HRRR WANTS TO DVLP SOME FOG BY 13Z WITH IT
LINGERING THRU THE EARLY AFTN HOURS WHILE THE RAP HAS NOTHING. AT
THIS POINT FOG LOOKS UNLIKELY SO WILL NOT MENTION IT IN THE TAF.
FOR THIS AFTN THRU TONIGHT WILL KEEP CONDITIONS VFR. AS FOR WINDS
THEY WILL BE LIGHT SSE THIS MORNING AND THEN BECOME LIGHT NELY BY
EARLY AFTN. FOR TONIGHT THEY SHOULD GRADUALLY BECOME DRAINAGE
DURING THE EARLY EVENING HOURS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM...RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
608 AM EST WED JAN 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 359 AM EST WED JAN 14 2015
COLD CONDITIONS WILL PERSIST UNDER THE INFLUENCE OF SURFACE HIGH
PRESSURE THROUGH TONIGHT BEFORE A STEADY WARM UP BEGINS FOR THE
LATTER PORTION OF THE WEEK AND INTO THE WEEKEND WITH ARCTIC AIR
MODERATING SIGNIFICANTLY ACROSS THE AREA.
&&
.NEAR TERM /TODAY/...
ISSUED AT 359 AM EST WED JAN 14 2015
TEMPERATURES ARE THE ONLY MAJOR FORECAST VARIABLE TODAY AS WHILE A
VERY WEAK UPPER WAVE PASSES TO OUR NORTH...DRY MID LEVEL AIR AND A
NEAR TOTAL LACK OF LIFT ASSOCIATED WITH THE WAVE WILL PREVENT ANY
PRECIPITATION FROM OCCURRING.
TEMPERATURES ARE TRICKY AS SOME LOW LEVEL CLOUD HAS BUILT BACK
INTO CENTRAL INDIANA OVERNIGHT AND HIGH LEVEL CLOUD WILL BE ON THE
INCREASE LATER IN THE DAY.
HOWEVER...WITH SOME MINOR ADJUSTMENTS NORTH WHERE TEMPERATURES
WILL BE STARTING THE DAY NEAR OR BELOW ZERO...BLEND OF AVAILABLE
GUIDANCE PROVIDES AN ADEQUATE STARTING POINT...WITH THE MID TO
UPPER TEENS ACROSS THE NORTH AND LOW TO MID 20S ACROSS THE SOUTH.
APPARENT TEMPERATURES WILL BE COLD THROUGH THE MORNING BUT WELL
ABOVE ADVISORY CRITERIA.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 359 AM EST WED JAN 14 2015
DRY WEATHER WILL PERSIST THROUGH THE SHORT TERM AS DRY MID LEVELS
WILL CONTINUE TO INHIBIT PRECIPITATION CHANCES EVEN WITH A WEAK
WAVE PASSING NEAR THE AREA THURSDAY. THIS LEAVES TEMPERATURES
AGAIN AS THE ONLY MAJOR FORECAST VARIABLE.
CANNOT PARTICULARLY QUIBBLE WITH MODEL CONSENSUS EXCEPT ACROSS THE
NORTH WHERE SOME LINGERING SNOW COVER PERSISTS. HAVE GENERALLY
TIGHTENED THE FORECAST TEMP GRADIENT ACROSS THE AREA A BIT.
APPARENT TEMPERATURES WILL AGAIN APPROACH OR BRIEFLY GO BELOW ZERO
ACROSS THE NORTH TONIGHT INTO THURSDAY MORNING...BUT REMAIN AGAIN
WELL ABOVE ADVISORY CRITERIA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 253 AM EST WED JAN 14 2015
DRY WEATHER IS EXPECTED DURING THIS PERIOD ALONG WITH MODERATING
TEMPERATURES. GFS AND ECMWF AGREE THAT A QUICK MOVING SHORT WAVE
WILL PUSH THROUGH THE GREAT LAKES ON SATURDAY NIGHT AND
SUNDAY...HOWEVER THIS SYSTEM LOOKS TO REMAIN RATHER MOISTURE
STARVED AS BEST FORCING REMAINS WELL NORTH OF CENTRAL INDIANA.
NORTHWEST FLOW PERSISTS ON SUNDAY NIGHT INTO MONDAY IN THE WAKE OF
THE PASSING SHORT WAVE...CONTINUING THE FLOW OF DRY...BUT MILD
PACIFIC AIR.
&&
.AVIATION /DISCUSSION FOR THE 141200 TAFS/...
ISSUED AT 609 AM EST WED JAN 14 2015
SCT MVFR CIGS AT HUF AND BMG WILL LINGER FOR A COUPLE OF HOURS
THIS MORNING BEFORE A RETURN TO VFR CONDITIONS.
SATELLITE SHOWS THE MVFR CIGS OVER SOUTHERN INDIANA. RUC INDICATES
THESE CLOUDS WILL ADVECT EAST AS HIGH PRESSURE TO THE NORTHWEST
SLOWLY BUILDS ACROSS CENTRAL INDIANA. SOME HIGHER
CLOUDS...VFR...OVR THE MISSISSIPPI RIVER VALLEY AREA EXPECTED TO
ADVECT ACRS THE TAF SITES LATER THIS MORNING.
FORECAST SOUNDINGS DRY OUT OVERNIGHT AS WEAK SUBSIDENCE
RESUMES...FORECAST SOUNDINGS DRY OUT AND CONDITIONS REMAIN VFR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM...PUMA
AVIATION...JP
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 CLEVELAND OH
711 AM EST WED JAN 14 2015
.SYNOPSIS...
HIGH PRESSURE ACROSS THE REGION WILL STAY IN PLACE THROUGH
THURSDAY. A COLD FRONT WILL SINK SOUTH ACROSS THE GREAT LAKES
THURSDAY NIGHT INTO FRIDAY...THEN RETREAT BACK NORTH AS A WARM
FRONT ON SATURDAY. LOW PRESSURE WILL MOVE ACROSS THE NORTHERN
LAKES AND TAKE A COLD FRONT ACROSS THE LOCAL AREA SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PESKY STRATUS AND FLURRIES CONTINUE THIS MORNING ACROSS NW OHIO.
THE STRATUS HAS BEEN DRIFTING FOR 24 HRS NOW...SHRINKING AND
EXPANDING DIURNALLY. SO THIS MORNING IT IS OVER TOL/FDY. IT IS
ENTIRELY POSSIBLE THAT LOCATIONS COULD GET A COATING OF DRY
SNOW THIS MORNING. ALL OTHERS WILL BE DRY. FORECAST WILL LEAN
TOWARD SOME BREAKS THIS AFTERNOON/PARTLY CLOUDY...BUT STRATUS MAY
VERY WELL STILL BE LINGERING IN THE AREA OR DRIFT EAST AGAIN. HAVE
MADE MINOR SKY GRID MODIFICATIONS WITH THIS EARLY MORNING UPDATE
TO ACCOUNT FOR AN EASTWARD DRIFT. PATCHY FOG HAS BECOME MORE
WIDESPREAD OVER THE LAST COUPLE OF HOURS. HAVE ADDED THAT TO THE
FORECAST FOR FIRST THING THIS MORNING. ANOTHER AREA OF STRATUS
WILL HUG THE SOUTHEAST BORDER SO EXPECT A CLOUDY PERIOD WITH
BREAKS LATER. WITH HIGH PRESSURE OVERHEAD WINDS WILL BE LIGHT.
COLD TO START WITH A NUMBER OF SUB- ZERO READINGS. SEE NO REASON
TO STRAY FAR FROM GUIDANCE TODAY WHICH GIVES TEENS WEST TO LOWER
20S EAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT WILL BE THE LAST SUPER COLD NIGHT WITH TEMPERATURES
MODIFYING THROUGH THE END OF THE WEEK. THE HIGH WILL STILL BE
OVERHEAD/CENTERED TO OUR EAST BUT EXPECT A FEW CLOUDS WITH A
MINOR SHORTWAVE MOVING ACROSS THE REGION. WINDS WILL BE LIGHT FROM
THE SOUTHWEST. WITH THAT WILL ONLY TAKE LOWS INTO THE POSITIVE
SINGLE DIGITS.
EVEN WITH THE SOUTHWEST FLOW THURSDAY WE DO NOT GET A BIG PUSH OF
WARM AIR...MID/UPPER 20S WILL BE ALL WE CAN DO BUT THIS IS AN
IMPROVEMENT ON THE RECENT PAST. LOW PRESSURE WILL TRACK ACROSS
SOUTHERN CANADA...THE NORTHERN LAKES...AND INTO QUEBEC. THE BEST
PUSH WITH THE COLD FRONT WILL STAY TO OUR NORTH AND WE WILL SEE IN
INCREASE IN CLOUDS AND SOME SNOW SHOWERS TOWARD FRIDAY
MORNING...MORE SO WHEN THE FLOW COMES AROUND TO THE WEST-
NORTHWEST. GFS IS STILL A LITTLE MORE AGGRESSIVE WITH COLDER AIR.
WITH A LAKE THAT IS INCREASINGLY ICE COVERED AND LIMITED
ENVIRONMENTAL MOISTURE NOT TOO CONCERNED ABOUT DECENT LAKE EFFECT.
WILL CONTINUE TO GO WITH A CHANCE OF SNOW SHOWERS FOR NE OH/NW PA.
RIDGE MOVES IN QUICKLY FRIDAY AFTERNOON AND ANY PRECIP WOULD BE
COMING TO AN END. WITH THE COLD AIR ADVECTION FRIDAY MAY SEE TEMPS
JUST HOLD STEADY IN THE LOWER 20S/AROUND 20. SO CHILLY AGAIN
FRIDAY NIGHT ESPECIALLY ACROSS THE EAST...BUT WESTERN AREAS WILL
BE BETTER OFF WITH THE APPROACH OF A WARM FRONT AND SOUTHERLY
FLOW. GENERALLY TEENS WITH SOME SINGLE DIGITS FOR NW PA.
THE WARM FRONT LIFTS NORTH ACROSS THE AREA ON SATURDAY AND
TEMPERATURES WILL WARM...ENOUGH TO GET US ABOVE AVERAGE. WILL GO
WITH UPPER 30S/AROUND 40 AFTER THE COOL START. LOW PRESSURE WILL
BE MOVING ACROSS THE NORTHERN LAKES SATURDAY NIGHT...BUT THE LOCAL
AREA WILL STILL BE IN THE WARM SECTOR SO TEMPERATURES WILL ONLY
FALL BACK TO AROUND FREEZING.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY. ALL THE MODELS ARE IN
AGREEMENT...EXCEPT THE ECMWF IS DRIER WITH THIS FEATURE. NONE THE
LESS IT WILL BE A LIGHT SNOW EVENT WITH CHANCE POPS AT THIS
TIME...THEY MIGHT NEED TO BE RAISED. SOME SNOW COULD LINGER OVER THE
SNOW BELT SUNDAY NIGHT IN THE NORTHWEST FLOW WITH A LAKE AND 850 MB
TEMPERATURE DIFFERENCE OF 13C. THE POPS MAY HAVE TO BE RAISED AS THE
TRENDS BECOME CLEARER. DRY MONDAY WITH A RIDGE ACROSS THE AREA AND
THEN ANOTHER LOW WILL BE APPROACHING THE AREA FOR TUESDAY. SOME
TIMING ISSUES AT THIS TIME...WILL KEEP TUESDAY DRY AND CONTINUE THE
CHANCE TUESDAY NIGHT. USED A BLEND OF GUIDANCE FOR THE TEMPERATURE
FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A RIDGE WILL BE BUILDING INTO THE AREA TODAY AND THEN IT WILL
SHIFT SOUTH THURSDAY. STRATUS DEVELOPED OVER NW OHIO AND IT WILL
BE SOMEWHAT SLOW TO BURNOFF. THE HRRR AND RUC MODELS MOVES LOW
CLOUDS FROM WEST TO EAST...NONE OF THE OTHER MODELS DO THIS. THIS
SEEMS REASONABLE...SO WENT ALONG WITH IT. THE LOW CLOUDS WILL
DECREASE SLOWLY FROM THE WEST STARTING LATE THIS AFTERNOON. SOME
MID CLOUDS WILL BE OVER THE AREA TONIGHT ASSOCIATED WITH A WEAK
TROF ALOFT.
.OUTLOOK...NON VFR POSSIBLE ACROSS NE OH/NW PA THURSDAY NIGHT INTO
FRIDAY AND AGAIN LATE SATURDAY NIGHT INTO SUNDAY.
&&
.MARINE...
AT THIS TIME NOT EXPECTING GALE FORCE WINDS THROUGH THE PERIOD...IT
COULD BE CLOSE AT TIMES AS SEVERAL WEATHER SYSTEMS WILL MOVE THROUGH.
A RIDGE WILL BE BUILDING ACROSS THE LAKE TODAY AND THEN IT WILL
SHIFT EAST TONIGHT AND A WEAK FRONT WILL MOVE THROUGH THURSDAY
NIGHT. SUSTAINED WINDS OF 30 KNOTS ARE LIKELY AND THEN A RIDGE WILL
BUILD IN QUICKLY BY LATE FRIDAY. STRONG SOUTHWEST WINDS WILL DEVELOP
ON SATURDAY IN THE WARM ADVECTION...HOWEVER...THEY WILL NOT MIX DOWN
TOTALLY. A COLD FRONT WILL MOVE THROUGH ON SUNDAY WITH WINDS BELOW
GALE FORCE. THIS WILL HAVE TO BE WATCHED. NOT MUCH WIND ON MONDAY AS
A RIDGE WILL BRIEFLY MOVE ACROSS THE LAKE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
657 AM EST WED JAN 14 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE STRETCHED FROM THE MID MISSISSIPPI
VALLEY TO THE NEW ENGLAND STATES WILL MAINTAIN CONTROL OF OUR
LOCAL WEATHER THROUGH MUCH OF THURSDAY. A VIGOROUS UPPER LEVEL
DISTURBANCE AND ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST FROM THE
GREAT LAKES AND CROSS THE STATE THURSDAY NIGHT AND EARLY
FRIDAY. THIS RELATIVELY MOISTURE STARVED SYSTEM WILL BE ACCOMPANIED
BY SOME SNOW SHOWERS AND FOLLOWED BY ANOTHER SHOT OF COLDER AIR
FOR FRIDAY AND ON INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A RELATIVELY THICK SHIELD OF MID AND HIGH CLOUDS COVERS ALL BUT
THE NW MTNS OF PA EARLY TODAY AS A RELATIVELY WEAK AND FAST
MOVING UPPER TROUGH HEADS ENE ACROSS THE CENTRAL APPALACHIANS.
A SHALLOW LAYER OF MOIST AND ANOMALOUS EASTERLY FLOW OFF THE
ATLANTIC WAS COMBINING WITH A BROAD AREA OF MODERATELY STRONG
850-700 MB FGEN AND UVVEL OVER THE MID ATLANTIC PIEDMONT REGION...
TO PRODUCE A BLOSSOMING AREA OF WINTRY PRECIP /FALLING MAINLY AS
PERIODS OF LIGHT SNOW ALONG AND JUST TO THE NW OF I95 IN NRN VA
AND MD/.
WHILE CLOUDS ACROSS SOUTHERN PENN KEEP MIN TEMPS IN THE TEENS
THERE...MAINLY CLEAR SKIES...VERY DRY TEMPS AND ESSENTIALLY CALM
AIR WILL LEAD TO FRIGID TEMPS IN THE -5 TO -15F RANGE NEAR AND TO
THE WEST OF KBFD THROUGH SUNRISE.
00Z HI RES ARW AND NMM...ALONG WITH THE 07Z HRRR AND RAP PRECIP
DEPICTION IS ALREADY TOO FAR SOUTH BY NEARLY 50 NM /AND BARELY
BRUSHES THE DC AREAS WITH ANY MEASURABLE SNOW THIS MORNING/.
00Z 12KM NAM AND 03Z SREF ARE THE FURTHER NORTH WITH THE LEADING
EDGE OF THE LIGHT SNOW AND APPEAR TO BE MORE ON TARGET WITH ITS
PRESENT LOCATION. ANOMALOUS EASTERLY 925 MB FLOW SHOULD HELP TO
MAINTAIN SOME VERY LIGHT SNOW AS IT APPROACHES THE MASON DIXON
LINE AROUND OR SHORTLY AFTER DAYBREAK.
RATHER THICK MID-LEVEL CLOUDS WILL LIKELY BE AFFECTING AT LEAST
THE SOUTHERN PORTION OF THE FORECAST AREA TO START THE DAY TODAY.
SOME LIGHT SNOW AND A DUSTING IS POSSIBLE TO THE SOUTH OF A KTHV
TO KLNS LINE LATE THIS MORNING AS THE AXIS OF STRONGEST EASTERLY
LLVL FLOW AND A FEW EAST/WEST BANDS OF WEAK 850-700 MB
FRONTOGENESIS AND UVVEL BRUSHES THAT AREA.
MADE SOME MINOR TWEAKS TO CLOUDS/TEMPS/POPS...AND LIGHT SNOW
AMOUNTS ACROSS THE FAR SE ZONES TODAY. ANY LIGHT SNOW ACCUM TO THE
SOUTH OF A KTHV TO KLNS LINE SHOULD BE LIMITED TO UNDER 0.5 OF AN
INCH.
AND WILL MAKE JUST SOME MINOR ADJUSTMENTS TO THE ALREADY
VERY LIGHT QPF/SNOW FORECAST FOR OUR EXTREME SE CWA...NEAR AND TO
THE SOUTH OF STATE RT 30 FROM YORK TO LANCASTER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
AS THE SFC LOW LOCATED OFFSHORE STARTS TO BECOME BETTER ORGANIZED
ALONG THE FRONTAL ZONE...GEOSTROPHIC FLOW SHOULD TURN BACK MORE TO
THE NORTH ONCE AGAIN AND FORCE THE CLOUDS BACK OUT OF THE AREA
FROM NW TO SE LATE TODAY.
RIDGE OF HIGH PRESSURE WILL SLIDE EAST FROM THE OHIO VALLEY AND
CROSS OUR FCST AREA LATE TONIGHT AND EARLY THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A BROADENING LONGWAVE TROF OVER THE EASTERN HALF OF THE CONUS WILL
LEAD TO COLD AND GENERALLY DRY WEATHER ACROSS THE REGION THROUGH THE
REMAINDER OF THE WEEK. UPPER FLOW IS FORECAST TO BECOME ZONAL FOR
A SHORT PERIOD OVER THE WEEKEND BEFORE ANOTHER TROF REDEVELOPS
FROM THE OHIO VALLEY EASTWARD NEXT WEEK.
THE PATTERN THROUGH THIS WEEK SHOULD SEE SEVERAL WEAK AND MAINLY
DRY SHORTWAVES IN THE NRN STREAM THAT COULD BRING A SLIGHT CHANCE
OF LIGHT PCPN...MAINLY FRIDAY AFTN IN THE NW MTNS...AND LATE THIS
UPCOMING WEEKEND. CONSIDERING THE PHASE SHIFT AND INCONSISTENCIES
OF THE ENSEMBLES...HAVE LEFT ONLY CHANCE POPS. TEMPS SHOULD SEE A
GENERAL RISE AS THE WEEK CONTINUES INTO THE WEEKEND...WITH HIGHS
CLIMBING INTO THE 40S ALONG THE SOUTHERN TIER POSSIBLE BY LATE IN
THE WEEKEND.
THE RENEWED TROFFING WILL SEND TEMPS BACK DOWN NEXT WEEK...BUT
AT THIS POINT NOT LOOKING AS COLD AS THIS WEEK. CHANCES OF PCPN
REMAIN LOW FOR NEXT WEEK AS WELL WITH LITTLE TO NO ROOM FOR
AMPLIFICATION OF SHORTWAVE ENERGY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
IN THE WAKE OF A WEAK SHORTWAVE EXITING THE SOUTHERN MID ATLANTIC
STATES THIS MORNING...AN EXPANSIVE AREA OF LOW CLOUDS WILL MOVE
INTO THE AIRSPACE FROM THE SW. MEDIUM-HIGH CONFIDENCE IN WDSPRD
LOW END VFR TO MVFR CIGS DEVELOPING BY AFTN AND LASTING THROUGH
TONIGHT. LOW LEVEL MSTR ASCENDING THE SW MTNS VIA WEAK UPSLOPE
FLOW SUGGESTS IFR IS POSSIBLE AT JST...WITH FCST SOUNDINGS
INDICATING FAVORABLE SET-UP FOR -FZDZ. LOW CLOUDS SHOULD GET
TRAPPED BENEATH INVERSION AND MAINTAIN LOW/REDUCED CIGS OVERNIGHT
INTO THURSDAY MORNING.
OUTLOOK...
THU...VFR/NO SIG WX.
FRI...MVFR CIGS/-SHSN POSSIBLE N/W. VFR ELSEWHERE. NW WIND GUSTS
20-30KTS.
SAT..VFR/NO SIG WX.
SUN...IFR RESTRICTIONS POSSIBLE WITH CHANCE OF SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
546 AM EST WED JAN 14 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE STRETCHED FROM THE MID MISSISSIPPI
VALLEY TO THE NEW ENGLAND STATES WILL MAINTAIN CONTROL OF OUR
LOCAL WEATHER THROUGH MUCH OF THURSDAY. A VIGOROUS UPPER LEVEL
DISTURBANCE AND ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST FROM THE
GREAT LAKES AND CROSS THE STATE THURSDAY NIGHT AND EARLY
FRIDAY. THIS RELATIVELY MOISTURE STARVED SYSTEM WILL BE ACCOMPANIED
BY SOME SNOW SHOWERS AND FOLLOWED BY ANOTHER SHOT OF COLDER AIR
FOR FRIDAY AND ON INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A RELATIVELY THICK SHIELD OF MID AND HIGH CLOUDS COVERS ALL BUT
THE NW MTNS OF BENN EARLY TODAY AS A RELATIVELY WEAK AND FAST
MOVING UPPER TROUGH HEADS ENE ACROSS THE CENTRAL APPALACHIANS.
A SHALLOW LAYER OF MOIST AND ANOMALOUS EASTERLY FLOW OFF THE
ATLANTIC WAS COMBINING WITH A BROAD AREA OF MODERATELY STRONG
850-700 MB FGEN AND UVVEL OVER THE MID ATLANTIC PIEDMONT REGION...
TO PRODUCE A BLOSSOMING AREA OF WINTRY PRECIP /FALLING MAINLY AS
PERIODS OF LIGHT SNOW ALONG AND JUST TO THE NW OF I95 IN NRN VA
AND MD/.
WHILE CLOUDS ACROSS SOUTHERN PENN KEEP MIN TEMPS IN THE TEENS
THERE...MAINLY CLEAR SKIES...VERY DRY TEMPS AND ESSENTIALLY CALM
AIR WILL LEAD TO FRIGID TEMPS IN THE -5 TO -15F RANGE NEAR AND TO
THE WEST OF KBFD THROUGH SUNRISE.
00Z HI RES ARW AND NMM...ALONG WITH THE 07Z HRRR AND RAP PRECIP
DEPICTION IS ALREADY TOO FAR SOUTH BY NEARLY 50 NM /AND BARELY
BRUSHES THE DC AREAS WITH ANY MEASURABLE SNOW THIS MORNING/.
00Z 12KM NAM AND 03Z SREF ARE THE FURTHER NORTH WITH THE LEADING
EDGE OF THE LIGHT SNOW AND APPEAR TO BE MORE ON TARGET WITH ITS
PRESENT LOCATION. ANOMALOUS EASTERLY 925 MB FLOW SHOULD HELP TO
MAINTAIN SOME VERY LIGHT SNOW AS IT APPROACHES THE MASON DIXON
LINE AROUND OR SHORTLY AFTER DAYBREAK.
RATHER THICK MID-LEVEL CLOUDS WILL LIKELY BE AFFECTING AT LEAST
THE SOUTHERN PORTION OF THE FORECAST AREA TO START THE DAY TODAY.
SOME LIGHT SNOW AND A DUSTING IS POSSIBLE TO THE SOUTH OF A KTHV
TO KLNS LINE LATE THIS MORNING AS THE AXIS OF STRONGEST EASTERLY
LLVL FLOW AND A FEW EAST/WEST BANDS OF WEAK 850-700 MB
FRONTOGENESIS AND UVVEL BRUSHES THAT AREA.
MADE SOME MINOR TWEAKS TO CLOUDS/TEMPS/POPS...AND LIGHT SNOW
AMOUNTS ACROSS THE FAR SE ZONES TODAY. ANY LIGHT SNOW ACCUM TO THE
SOUTH OF A KTHV TO KLNS LINE SHOULD BE LIMITED TO UNDER 0.5 OF AN
INCH.
AND WILL MAKE JUST SOME MINOR ADJUSTMENTS TO THE ALREADY
VERY LIGHT QPF/SNOW FORECAST FOR OUR EXTREME SE CWA...NEAR AND TO
THE SOUTH OF STATE RT 30 FROM YORK TO LANCASTER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
AS THE SFC LOW LOCATED OFFSHORE STARTS TO BECOME BETTER ORGANIZED
ALONG THE FRONTAL ZONE...GEOSTROPHIC FLOW SHOULD TURN BACK MORE TO
THE NORTH ONCE AGAIN AND FORCE THE CLOUDS BACK OUT OF THE AREA
FROM NW TO SE LATE TODAY.
RIDGE OF HIGH PRESSURE WILL SLIDE EAST FROM THE OHIO VALLEY AND
CROSS OUR FCST AREA LATE TONIGHT AND EARLY THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A BROADENING LONGWAVE TROF OVER THE EASTERN HALF OF THE CONUS WILL
LEAD TO COLD AND GENERALLY DRY WEATHER ACROSS THE REGION THROUGH THE
REMAINDER OF THE WEEK. UPPER FLOW IS FORECAST TO BECOME ZONAL FOR
A SHORT PERIOD OVER THE WEEKEND BEFORE ANOTHER TROF REDEVELOPS
FROM THE OHIO VALLEY EASTWARD NEXT WEEK.
THE PATTERN THROUGH THIS WEEK SHOULD SEE SEVERAL WEAK AND MAINLY
DRY SHORTWAVES IN THE NRN STREAM THAT COULD BRING A SLIGHT CHANCE
OF LIGHT PCPN...MAINLY FRIDAY AFTN IN THE NW MTNS...AND LATE THIS
UPCOMING WEEKEND. CONSIDERING THE PHASE SHIFT AND INCONSISTENCIES
OF THE ENSEMBLES...HAVE LEFT ONLY CHANCE POPS. TEMPS SHOULD SEE A
GENERAL RISE AS THE WEEK CONTINUES INTO THE WEEKEND...WITH HIGHS
CLIMBING INTO THE 40S ALONG THE SOUTHERN TIER POSSIBLE BY LATE IN
THE WEEKEND.
THE RENEWED TROFFING WILL SEND TEMPS BACK DOWN NEXT WEEK...BUT
AT THIS POINT NOT LOOKING AS COLD AS THIS WEEK. CHANCES OF PCPN
REMAIN LOW FOR NEXT WEEK AS WELL WITH LITTLE TO NO ROOM FOR
AMPLIFICATION OF SHORTWAVE ENERGY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
14/09Z UPDATE...MVFR CIGS HAS DEVELOPED ON NRN PERIPHERY OF
WINTRY PCPN ZONE CURRENTLY EXPANDING NEWD BTWN THE I-81 AND I-95
CORRIDORS. AMENDED MDT/LNS TO LOWER CIGS WHICH SHOULD PERSIST
THROUGH AT LEAST MIDDAY. OBS TRENDS SUGGEST JST WILL BE THE NEXT
SITE TO DROP TO MVFR AS LOW CIGS SHIFT NWD FROM THE NRN WV/MD
PNHDL. EXTRAPOLATION OF RADAR TRENDS NOW SUGGESTS -SN MAY CLIP
MDT/LNS WITH BETTER CHANCE AT LNS VS. MDT.
14/06Z...A WEAK SHORTWAVE LIFTING NEWD FROM THE TN VALLEY/CENTRAL
APPALACHIANS WILL CROSS THE SOUTHERN MID-ATLANTIC STATES EARLY
TODAY. THE ENERGY IS EXPECTED TO INVIGORATE AN AREA OF LOW
PRESSURE EAST OF THE NC OUTER BANKS WHICH IS THEN FORECAST TO EXIT
NORTHEAST WELL OFF THE EAST COAST. WHILE THE BULK OF THE
PRECIPITATION WITH THIS SYSTEM IS FORECAST TO REMAIN S/E OF THE
AIRSPACE...SOME LOWER CIGS ARE A GOOD BET...AT LEAST AOB 5KFT OVER
THE SOUTH-CENTRAL/SE TERMINALS. HIGHEST CONFIDENCE IN POTENTIAL
IFR CONDITIONS WOULD BE AT JST GIVEN UPSLOPE FLOW AND SUPPORT FROM
GUIDANCE.
OUTLOOK...
THU...VFR/NO SIG WX.
FRI...MVFR CIGS/-SHSN POSSIBLE N/W. VFR ELSEWHERE. NW WIND GUSTS
20-30KTS.
SAT..VFR/NO SIG WX.
SUN...IFR RESTRICTIONS POSSIBLE WITH CHANCE OF SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
509 AM EST WED JAN 14 2015
.SYNOPSIS...
A LARGE AREA OF HIGH PRESSURE STRETCHED FROM THE MID MISSISSIPPI
VALLEY TO THE NEW ENGLAND STATES WILL MAINTAIN CONTROL OF OUR
LOCAL WEATHER THROUGH MUCH OF THURSDAY. A VIGOROUS UPPER LEVEL
DISTURBANCE AND ASSOCIATED COLD FRONT WILL PUSH SOUTHEAST FROM THE
GREAT LAKES AND CROSS THE STATE THURSDAY NIGHT AND EARLY
FRIDAY. THIS RELATIVELY MOISTURE STARVED SYSTEM WILL BE ACCOMPANIED
BY SOME SNOW SHOWERS AND FOLLOWED BY ANOTHER SHOT OF COLDER AIR
FOR FRIDAY AND ON INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
HIGH CLOUDS CONTINUE TO SPREAD NORTH AND GRADUALLY THICKEN-UP
ACROSS THE SOUTHERN HALF OF PENN...WHILE MAINLY CLEAR SKIES ACROSS
THE NORTHERN MTNS HAVE ALLOWED TEMPS TO DROP TO FRIGID LEVELS OF
5-10 BELOW ZERO IN SOME RURAL VALLEY LOCATIONS OF ELK...MCKEAN AND
POTTER COUNTIES. SCHOOL/MESO OBS FROM THAT AREA SHOW A -14F INVOF
MT JEWETT IN SOUTHERN MCKEAN COUNTY...AND -11F IN THE CITY OF
BRADFORD.
TEMPS SHOULD FALL UP TO ANOTHER FEW DEG F ACROSS THE NRN
TIER...WHILE THE INCREASING CLOUDS FURTHER SOUTH LEVEL OFF THE
TEMPS.
THE SOUTHERN THIRD OF THE STATE SHOULD SEE TEMPS HOLDING STEADY IN
THE MID TO UPPER TEENS...OR FALL JUST A FEW DEG F UNDER THE
THICKEST CLOUD COVER.
WILL BE CLOSELY MONITORING THE PROGRESSION OF THE NRN EDGE OF
LIGHT SNOW MAKING IT/S WAY NNE ALONG THE I-95 CORRIDOR /AND NOW
OVERSPREADING THE D.C. AREA. 00Z HI RES ARW AND NMM...ALONG WITH
THE 07Z HRRR AND RAP PRECIP DEPICTION IS ALREADY TOO FAR SOUTH BY
NEARLY 50 NM /AND BARELY BRUSHES THE DC AREAS WITH ANY MEASURABLE
SNOW THIS MORNING/.
00Z 12KM NAM AND 03Z SREF ARE THE FURTHER NORTH WITH THE LEADING
EDGE OF THE LIGHT SNOW AND APPEAR TO BE MORE ON TARGET WITH ITS
PRESENT LOCATION. ANOMALOUS EASTERLY 925 MB FLOW SHOULD HELP TO
MAINTAIN SOME VERY LIGHT SNOW AS IT APPROACHES THE MASON DIXON
LINE AROUND OR SHORTLY AFTER DAYBREAK.
WILL MAKE JUST SOME MINOR ADJUSTMENTS TO THE ALREADY VERY LIGHT
QPF/SNOW FORECAST FOR OUR EXTREME SE CWA...NEAR AND TO THE SOUTH
OF STATE RT 30 FROM YORK TO LANCASTER.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM THURSDAY/...
RATHER THICK MID-LEVEL CLOUDS WILL LIKELY BE AFFECTING AT LEAST
THE SOUTHERN PORTION OF THE FORECAST AREA TO START THE DAY TODAY.
SOME LIGHT SNOW AND A DUSTING IS POSSIBLE TO THE SOUTH OF A KTHV
TO KLNS LINE LATE THIS MORNING AS THE AXIS OF STRONGEST EASTERLY
LLVL FLOW AND A FEW EAST/WEST BANDS OF WEAK 850-700 MB
FRONTOGENESIS AND UVVEL BRUSHES THAT AREA.
AS THE SFC LOW OFFSHORE STARTS TO BECOME BETTER ORGANIZED ALONG
THE FRONTAL ZONE...GEOSTROPHIC FLOW SHOULD TURN BACK MORE TO THE
NORTH ONCE AGAIN AND FORCE THE CLOUDS BACK OUT OF THE AREA FROM NW
TO SE.
IT WILL REMAIN COLD TODAY AND HIGHS IN THE 20S WILL BE WELL BELOW
NORMAL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A BROADENING LONGWAVE TROF OVER THE EASTERN HALF OF THE CONUS WILL
LEAD TO COLD AND GENERALLY DRY WEATHER ACROSS THE REGION THROUGH THE
REMAINDER OF THE WEEK. UPPER FLOW IS FORECAST TO BECOME ZONAL FOR
A SHORT PERIOD OVER THE WEEKEND BEFORE ANOTHER TROF REDEVELOPS
FROM THE OHIO VALLEY EASTWARD NEXT WEEK.
THE PATTERN THROUGH THIS WEEK SHOULD SEE SEVERAL WEAK AND MAINLY
DRY SHORTWAVES IN THE NRN STREAM THAT COULD BRING A SLIGHT CHANCE
OF LIGHT PCPN...MAINLY FRIDAY AFTN IN THE NW MTNS...AND LATE THIS
UPCOMING WEEKEND. CONSIDERING THE PHASE SHIFT AND INCONSISTENCIES
OF THE ENSEMBLES...HAVE LEFT ONLY CHANCE POPS. TEMPS SHOULD SEE A
GENERAL RISE AS THE WEEK CONTINUES INTO THE WEEKEND...WITH HIGHS
CLIMBING INTO THE 40S ALONG THE SOUTHERN TIER POSSIBLE BY LATE IN
THE WEEKEND.
THE RENEWED TROFFING WILL SEND TEMPS BACK DOWN NEXT WEEK...BUT
AT THIS POINT NOT LOOKING AS COLD AS THIS WEEK. CHANCES OF PCPN
REMAIN LOW FOR NEXT WEEK AS WELL WITH LITTLE TO NO ROOM FOR
AMPLIFICATION OF SHORTWAVE ENERGY.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
14/09Z UPDATE...MVFR CIGS HAS DEVELOPED ON NRN PERIPHERY OF
WINTRY PCPN ZONE CURRENTLY EXPANDING NEWD BTWN THE I-81 AND I-95
CORRIDORS. AMENDED MDT/LNS TO LOWER CIGS WHICH SHOULD PERSIST
THROUGH AT LEAST MIDDAY. OBS TRENDS SUGGEST JST WILL BE THE NEXT
SITE TO DROP TO MVFR AS LOW CIGS SHIFT NWD FROM THE NRN WV/MD
PNHDL. EXTRAPOLATION OF RADAR TRENDS NOW SUGGESTS -SN MAY CLIP
MDT/LNS WITH BETTER CHANCE AT LNS VS. MDT.
14/06Z...A WEAK SHORTWAVE LIFTING NEWD FROM THE TN VALLEY/CENTRAL
APPALACHIANS WILL CROSS THE SOUTHERN MID-ATLANTIC STATES EARLY
TODAY. THE ENERGY IS EXPECTED TO INVIGORATE AN AREA OF LOW
PRESSURE EAST OF THE NC OUTER BANKS WHICH IS THEN FORECAST TO EXIT
NORTHEAST WELL OFF THE EAST COAST. WHILE THE BULK OF THE
PRECIPITATION WITH THIS SYSTEM IS FORECAST TO REMAIN S/E OF THE
AIRSPACE...SOME LOWER CIGS ARE A GOOD BET...AT LEAST AOB 5KFT OVER
THE SOUTH-CENTRAL/SE TERMINALS. HIGHEST CONFIDENCE IN POTENTIAL
IFR CONDITIONS WOULD BE AT JST GIVEN UPSLOPE FLOW AND SUPPORT FROM
GUIDANCE.
OUTLOOK...
THU...VFR/NO SIG WX.
FRI...MVFR CIGS/-SHSN POSSIBLE N/W. VFR ELSEWHERE. NW WIND GUSTS
20-30KTS.
SAT..VFR/NO SIG WX.
SUN...IFR RESTRICTIONS POSSIBLE WITH CHANCE OF SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...DEVOIR/LAMBERT
SHORT TERM...LA CORTE/LAMBERT
LONG TERM...LAMBERT/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
605 AM CST WED JAN 14 2015
.DISCUSSION...
12Z TAF DISCUSSION IN AVIATION SECTION BELOW.
&&
.AVIATION...
TOUGH START FOR THE TAF THIS MORNING. CIGS HAVE SCT TO VFR ACROSS
A LOT OF THE AREA WITH AN OVC 6000-8000FT CEILING. MVFR CIGS HAVE
FILLED BACK IN OVER KGLS AND KSGR. IT LOOKS LIKE THIS MIGHT BE THE
EXTENT AT WHICH DRIER AIR AROUND 925MB HAS MOVED INTO THE REGION
MIXING OUT THE MVFR CIGS. INITIAL THOUGHTS HAVE BEEN THAT NAM/HRRR
WAS ON RIGHT TRACK WITH PESSIMISTIC MVFR CIGS WITH DZ/RA BUT THINK
RAP/GFS HAS BEEN BETTER SHOWING THE DRIER AIR AT 925MB. CHANGED
TAF TO THIS THINKING OF THE RAP WITH VFR FOR THE NEXT 5-8HRS WITH
MVFR CIGS DEVELOPING AGAIN. WITH KSGR BECOMING MVFR AGAIN...MAY
SEE MVFR CIGS COME BACK TO KIAH/KHOU SOONER THAN EXPECTED. STILL
THINK IT WILL TAKE ISENTROPIC LIFT OVER THE FRONTAL BOUNDARY SOME
TIME FOR DZ TO DEVELOP. SHORT WAVE TROUGH SHOULD MOVE OVER THE
AREA SO THINK FORECAST IS ON TRACK WITH RA TONIGHT WITH MVFR CIGS.
MODELS DO BRING IN DRIER AIR ON THUR SO HOPEFULLY SEE CEILINGS
LIFT WITH IF ANYTHING SOME HIGH CLOUDS FOR THUR AFTERNOON.
39
&&
.PREV DISCUSSION... /ISSUED 423 AM CST WED JAN 14 2015/
DISCUSSION...
AN ACTIVE SUBTROPICAL JET WILL HELP KEEP CHANCES OF RAIN ACROSS SE
TEXAS THROUGH THURSDAY. AN UPPER TROUGH OVER THE SOUTHERN PLAINS
AND SOUTHERN ROCKIES WILL SHEAR OUT AS IT MOVES EASTWARD...BUT
SHORTWAVE TROUGHS MOVING ALONG THE UPPER FLOW WILL HELP PROVIDE
CHANCES FOR RAIN INTO THURSDAY MORNING.
HOWEVER...THE UNSEASONABLY COOL DAYTIME CONDITIONS WILL PERSIST
FOR ANOTHER DAY. HIGH PRESSURE AT THE SURFACE WILL KEEP NORTHERLY
WINDS IN PLACE WHILE THE CLOUD COVER WILL KEEP THE DIURNAL
TEMPERATURE RANGE UNDER 10 DEGREES BETWEEN TODAY AND TONIGHT. THE
PASSAGE OF THE SHORTWAVE TROUGH ACROSS THE AREA WILL SCATTER OUT
THE CLOUD DECK...ALTHOUGH HIGH CLOUDINESS MAY LINGER DUE TO THE
POSITION OF THE SUBTROPICAL JET. STILL FELT THAT ENOUGH SUN WILL
OCCUR TO HELP BRING HIGH TEMPERATURES ON THURSDAY INTO THE 50S.
THIS WILL MEAN THAT THURSDAY WILL BE THE FIRST DAY WITH THE HIGH
TEMPERATURES ABOVE THE 40S SINCE THE 7TH.
DRIER CONDITIONS ARE EXPECTED INTO THE WEEKEND AS THE UPPER
TROUGH MOVES EAST OF THE AREA AND A RIDGE BUILDS OVER THE WESTERN
PART OF THE COUNTRY. THIS WILL ALSO MEAN A WARMING TREND WITH
DAYTIME HIGHS INTO THE 60S OVER THE WEEKEND. THE MODELS DIFFER A
BIT ON THE EVOLUTION OF A SHORTWAVE TROUGH MOVING THROUGH THE
SOUTHERN PLAINS SATURDAY NIGHT AND SUNDAY. A COLD FRONT SHOULD
ALSO MOVE THROUGH SE TEXAS. HOWEVER...THE CONSENSUS IS FOR RAIN
CHANCES TO REMAIN LOW AHEAD OF THE FRONT. HIGH PRESSURE WILL THEN
KEEP DRY CONDITIONS IN PLACE THROUGH TUESDAY.
40
MARINE...
HIGH PRESSURE WILL REMAIN OVER THE PLAINS THE NEXT COUPLE OF DAYS
WHICH WILL SUPPORT NORTHERLY OFFSHORE WINDS. WINDS DO WEAKEN OVER
THE UPPER TX COAST FRI INTO SAT AS AN AREA OF LOW PRESSURE FORMS IN
THE PLAINS. SW WINDS DEVELOP SAT INTO SUN AHEAD OF THE NEXT COLD
FRONT. GFS AND ECMWF HAVE THE FRONT PUSHING OFF THE COAST SAT NIGHT
INTO SUN MORNING. GFS IS A BIT SLOWER THAN THE ECMWF BUT NOT BY
MUCH. GFS IS ALSO STRONGER WITH WINDS BEHIND THE FRONT. FORECAST
WINDS WERE INCREASED A BIT BEHIND THE FRONT. HIGH PRESSURE THEN
BUILDS OVER THE AREA FOR EARLY NEXT WEEK. WINDS BEHIND THE FRONT MAY
BE STRONG ENOUGH FOR SCA/SCEC TO POSSIBLY BE NEEDED.
39
AVIATION...
RIGHT NOW THERE IS A MIX OF MVFR/VFR CIGS WITH MAINLY AN OVC 8000FT
CEILING. DO THINK MVFR CIGS WILL DEVELOP BACK AGAIN AS ISENTROPIC
LIFT INCREASES OVER THE FRONT DURING THE LATE MORNING. RADAR SHOWS
SOME ISO AREAS OF DZ WITH SHRA OFF THE COAST SO AT LEAST SOME LIFT
IS OCCURRING. LATEST NAM/HRRR CONTINUE WITH RA DEVELOPING OVER THE
AREA. RAP/GFS/ECMWF KEEP MORE OF THE PRECIP OFFSHORE AND JUST
INLAND. MAY NEED TO REVISIT HOW WIDESPREAD -RA/DZ WILL BE FOR 12Z
TAF. LIKELY TO CONTINUE TO MENTION MVFR CIGS THROUGH MUCH OF THE TAF
PERIOD. MODELS DO INCREASE RA OVER THE AREA WED NIGHT INTO THUR
MORNING AS SHORT WAVE TROUGH ROTATES THROUGH. IN WAKE OF THE
SHORTWAVE THERE MAY BE...WAIT FOR IT...CLEARING!
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 43 36 53 34 58 / 20 30 10 0 0
HOUSTON (IAH) 45 38 53 36 58 / 20 50 10 0 0
GALVESTON (GLS) 46 41 52 43 55 / 30 60 30 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...40
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
513 AM CST WED JAN 14 2015
.AVIATION...
MOST OF THE AREA IS UNDER MVFR CONDITIONS WITH IFR PRIMARILY WEST
OF I-35 INTO THE HILL COUNTRY. AUS/SAT/SSF COULD ALSO TOUCH IFR
CIGS EARLY THIS MORNING WITH A COMBINATION OF SLIGHTLY LOWER
CEILINGS AND/OR LOWERING VSBY DUE TO LIGHT DRIZZLE FALLING IN
PORTIONS OF THE AREA. RADAR IS SHOWING WAVES OF VERY LIGHT PRECIP
BUT MOST METAR SITES ARE NOT REPORTING ANY DRIZZLE. THIS TOO WILL
BE FAIRLY SPOTTY THROUGH THE MORNING. THE ISENTROPIC LIFT WILL
CONTINUE AS MID LEVEL WINDS INCREASE WITH THE APROACH OF UPPER
LEVEL SYSTEM TO THE WEST. WILL LIKELY SEE A REPEAT OF YESTERDAY
WITH SOME SITES GOING UP TO VFR BY LATE IN THE AFTERNOON. HAVE DRT
HITTING THE VFR FIRST AROUND 23Z, FOLLOWED BY AUS/SAT/SSF SHORTLY
AFTER 00Z TONIGHT. HRRR SHOWS SOME VFR WORKING IN FROM THE
NORTHEAST BY EARLY AFTERNOON WITH GFS MOS SHOWING THE CIGS RISING
BY THE EVENING. NAM IS MUCH MORE PESSIMISTIC WITH IFR AND EVEN
LIFR MUCH OF THE DAY TODAY. WENT MORE WITH THE GFS/HRRR SOLUTION. WHILE
TODAY WILL BE CHALLENGING...ALL THE MODELS SHOW BIG IMPROVEMENTS
ON THURSDAY AS WAVE MOVES EAST ALLOWING FOR OVERALL CLOUDCOVER TO
DECREASE DRASTICALLY BY THU AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 319 AM CST WED JAN 14 2015/
SHORT TERM (TODAY THROUGH THURSDAY)...
GOES-WEST WATER VAPOR CHANNEL SHOWS AN UPPER LEVEL LOW SYSTEM OVER
NORTHERN ARIZONA. THIS SYSTEM IS FORECAST TO PUSH TO THE SOUTHEAST
THROUGHOUT THE DAY AND BECOME AN OPEN-WAVE THIS EVENING. UPPER
LEVEL MOISTURE ASSOCIATED WITH THE OPEN-WAVE WILL MOVE ACROSS THE
AREA THIS MORNING AND CONTINUE THROUGH LATE TONIGHT. AT THE
SURFACE...A SHALLOW COOL LAYER REMAINS WITH NORTHERLY WINDS IN CONTROL.
EXPECT MOSTLY CLOUDY TO CLOUDY SKIES WITH LIGHT RAIN/DRIZZLE
ACROSS MUCH OF THE AREA AS PULSES OF UPPER LEVEL MOISTURE AND
ISENTROPIC LIFT PREVAILS. A BIT COOLER THIS MORNING...ESPECIALLY
OVER THE HILL COUNTRY WITH LOWER 30S AND UPPER 30S ELSEWHERE.
TODAY`S HIGHS WILL REACH THE LOWER TO MID 40S DUE TO THE CLOUD COVERAGE.
RAIN CHANCES COME TO AN END BY NOON THURSDAY ACROSS MUCH OF THE
AREA AS THE UPPER LEVEL WAVE PUSHES TO EAST-SOUTHEAST...LEAVING
BEHIND A ZONAL FLOW ALOFT THROUGH THE WEEKEND.
LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)...
CLOUDS WILL NOT DISAPPEAR COMPLETELY FOR THE LATTER PART OF THE
WEEK AS MID TO UPPER LEVEL MOISTURE ARRIVES FROM THE WEST.
HOWEVER...A WARMING TREND IS IN STORE FOR FRIDAY INTO THE UPCOMING
WEEKEND AS SURFACE SOUTHERLY FLOW RETURNS. HIGHS ARE FORECAST TO
REACH MID 60S BOTH SATURDAY AND SUNDAY. A DRY PACIFIC FRONT IS
EXPECTED TO PUSH ACROSS THE AREA SATURDAY. IT MAY BRING SUNDAY`S
HIGHS DOWN A DEGREE OR TWO FROM THOSE OBSERVED SATURDAY. BY
MONDAY...SOUTHERLY FLOW RESUMES AND BRINGS HIGHS BACK TO THE LOWER 60S.
CAN`T RULE OUT FEW PASSING SHOWERS MONDAY AS AN UPPER LEVEL SHORT
WAVE RUSHES OVER THE REGION. NEXT RAIN CHANCES COULD COME MID WEEK AS
AN UPPER LEVEL DISTURBANCE PUSHES ACROSS THE AREA AND A SURFACE
LOW DEVELOPS ACROSS THE NORTHWEST GULF OF MEXICO.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 43 37 54 34 62 / 20 10 - 0 0
AUSTIN BERGSTROM INTL AIRPORT 43 36 54 31 61 / 20 20 - 0 0
NEW BRAUNFELS MUNI AIRPORT 44 38 54 34 62 / 20 20 - 0 0
BURNET MUNI AIRPORT 41 31 53 31 61 / 20 - - 0 0
DEL RIO INTL AIRPORT 48 38 56 37 62 / 20 - - 0 0
GEORGETOWN MUNI AIRPORT 42 32 52 31 61 / 20 - - 0 0
HONDO MUNI AIRPORT 46 38 57 33 62 / 20 - - 0 0
SAN MARCOS MUNI AIRPORT 44 37 53 33 61 / 20 20 - 0 0
LA GRANGE - FAYETTE REGIONAL 44 38 54 34 60 / 20 30 10 - 0
SAN ANTONIO INTL AIRPORT 45 38 56 35 62 / 20 10 - 0 0
STINSON MUNI AIRPORT 45 39 56 36 62 / 20 10 - 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...09
SYNOPTIC/GRIDS...17
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
311 AM MST WED JAN 14 2015
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 310 AM MST WED JAN 14 2015
PATCHY FOG AND WIDESPREAD LOW STRATUS ARE STILL AN ISSUE EARLY THIS
MORNING PER WEB CAMS AND 11-3.9 MICROMETER SATELLITE IMAGERY. MAINLY
CONCERNED ABOUT AREAS ALONG AND WEST OF THE LARAMIE RANGE...ALTHOUGH
INCREASING LOW-LEVEL MOISTURE HAS ALLOWED SOME OF THIS TO CREEP INTO
CHEYENNE IN THE LAST HOUR. ADDED AREAS OF DENSE FOG TO THE GRIDS FOR
THE INTERSTATE 80 SUMMIT AS WEAK UPSLOPE COMBINED WITH GOOD BOUNDARY
LAYER MOISTURE IS CONTRIBUTING TO VISIBILITY REDUCTIONS DOWN TO LESS
THAN A HALF MILE. SINCE THIS APPEARS TO BE CONFINED PRIMARILY TO THE
HIGHEST ELEVATIONS ALONG INTERSTATE 80...DECIDED AGAINST A DENSE FOG
ADVISORY ATTM. GFS/NAM BUFKIT SOUNDINGS SUGGEST ENOUGH DRYING IN THE
LOW LEVELS TO HELP SCATTER THINGS OUT BY AROUND 15Z...BUT WOULD NOT
BE SURPRISED TO SEE CLOUDS LINGER THROUGH THE AFTERNOON FOR WESTERN
AREAS. INCREASED CLOUD COVER FOR TODAY TO COMPENSATE FOR THE STRATUS
AND POTENTIAL FOR A FEW CIRRUS LATER ON. MIGHT SEE A REPEAT OF THIS
TONIGHT IN SOUTHWEST CARBON COUNTY BASED ON FORECAST SOUNDINGS...SO
ADDED PATCHY FOG DURING THAT TIME AS WELL. NO CONCERNS ELSEWHERE.
HEIGHT RISES WITH UPPER-LEVEL RIDGING OVER THE NEXT 24-48 HOURS WILL
SIGNAL A TRANSITION TO A MUCH WARMER AND DRIER WEATHER PATTERN THRU
THE END OF THE WEEK. 700-300 MILLIBAR MOISTURE FIELDS ARE RATHER DRY
AND SUBSIDENCE ALOFT SHOULD ELIMINATE ANY POTENTIAL FOR PRECIP OVER
THE NEXT FEW DAYS. AFTER A RELATIVELY COOL DAY TODAY...EXCELLENT LOW
LEVEL DOWNSLOPE WILL BECOME ESTABLISHED ON THU AND FRI. H7 TEMPS ARE
PROGGED IN THE +2 TO +4 DEG C RANGE OVER THE PLAINS AND MOS GUIDANCE
IS SHOWING MAX TEMPERATURES WELL INTO THE 50S. SHOULD BE WELL ABOVE
SEASONAL NORMALS WITH A FEW NEAR RECORD HIGHS POSSIBLE BY THE END OF
THE WEEK. PRESSURE FALLS ALREADY OBSERVED FROM CENTRAL MT INTO PARTS
OF NORTHEAST WY ARE EXPECTED TO EXPAND THROUGH THE REST OF THE WEEK
IN RESPONSE TO MID LEVEL ENERGY EMANATING FROM THE NEXT LARGE SCALE
SHORTWAVE CURRENTLY OFF THE PACIFIC COAST. THIS WILL STRENGTHEN LOW
LEVEL GRADIENTS...AND ULTIMATELY LEAD TO AN UPTICK IN WINDS FOR THU
AND FRI. MAY BE A LITTLE GUSTY TODAY FOR THE WIND PRONE AREAS...BUT
THE H85 CAG-CPR GRADIENT ONLY TOPS OUT AROUND 20 METERS AT 21Z. DO
NOT EXPECT ANYTHING MUCH MORE THAN 30-40 MPH.
BIGGER CONCERNS FOR LATE THU NIGHT THROUGH FRI. THE NAM H85 CAG-CPR
GRADIENT INCREASES TO 50-60 METERS BY 06Z FRI AND REMAINS HIGH INTO
THE AFTERNOON AND EVENING. THIS RESULTS IN A BELT OF 50 TO 60 KT H75
FLOW OVER THE PRIMARY WIND CORRIDOR OF SOUTHEAST WY. THE MODELS SHOW
STRONG SUBSIDENCE IN THE 700-500 MILLIBAR LAYER...SO A MARGINAL HIGH
WIND EVENT FOR THE GAP AREAS LOOKS PROBABLE. DID NOT ISSUE ANY WIND
HEADLINES THIS MORNING AS WE ARE STILL 4TH TO 5TH PERIOD...BUT LATER
SHIFTS WILL MORE THAN LIKELY NEED TO HOIST WATCHES FOR THE ARLINGTON
AND BORDEAUX AREAS. DO NOT THINK THIS WILL SPREAD INTO THE PLAINS IN
THE SHORT TERM...BUT A LITTLE CONCERNED THAT THE GFS SHOWS FAVORABLE
DOWNWARD MOTION SPREADING INTO CENTRAL LARAMIE COUNTY BY 18Z WITH 50
KT AVAILABLE UPSTAIRS. ALWAYS TOUGH TO HIT WARNING CRITERIA WITH LOW
LEVEL WARM ADVECTION...BUT WILL CERTAINLY NEED TO WATCH THOSE ZONES
JUST EAST OF THE LARAMIE RANGE ON FRI AFTERNOON FOR STRONG CHINOOK
WINDS APPROACHING 60 MPH.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 300 AM MST WED JAN 14 2015
THERE ARE MINOR DIFFERENCES WITH THE 00Z/06Z MEDIUM RANGE DETERMINISTIC
MODEL GUIDANCE...THEREFORE A BLEND OF OPERATIONAL GFS/ECMWF/GEM WILL
BE APPLIED. PROGRESSIVE FLOW WEST TO EAST FLOW ALOFT WILL DOMINATE
THE LONG TERM. SHORTWAVE TROUGH WILL TRACK EAST FROM THE PACIFIC
NORTHWEST FRIDAY NIGHT ACROSS THE FRONT RANGE AND NORTH/CENTRAL GREAT
PLAINS SATURDAY. ACCOMPANYING PACIFIC COLD FRONT AND MID/UPPER LEVEL
MOISTURE WILL PRODUCE INCREASING CLOUDS FRIDAY NIGHT AND SATURDAY
MORNING. LIGHT RAIN/SNOW WILL IMPACT NORTHEAST WY/WESTERN SD.
ISOLATED LIGHT OROGRAPHIC SNOW SHOWERS MAY DEVELOP OVER THE SOUTH
CENTRAL WY MOUNTAINS. ALBEIT COOLER COMPARED TO FRIDAY...DOWNSLOPE
WEST-NORTHWEST WINDS WILL TEMPERATURES TO RISE INTO THE 40S OVER
THE SOUTHEAST WY PLAINS AND SOUTHERN NE PANHANDLE SATURDAY AFTERNOON.
STRONG WESTERLY WINDS WITH GUSTS TO 60 MPH WILL BE POSSIBLE FOR WIND
PRONE AREAS OF SOUTHEAST WY PRIOR TO FROPA SATURDAY MORNING...THEN
DIMINISH TO 25-40 MPH ALONG AND EAST OF THE LARAMIE RANGE DURING
THE AFTERNOON.
UPPER RIDGE OVER THE INTERMOUNTAIN WEST FLATTENS SOMEWHAT SUNDAY AS
SHORTWAVE ENERGY PASSES EAST ALONG THE U.S.-CANADIAN BORDER. RESULTING
NEAR ZONAL FLOW ALOFT AND DOWNSLOPE FLOW LEE OF THE LARAMIE RANGE
WILL PROVIDE ABOVE NORMAL TEMPERATURES IN THE 40S. LIGHT OROGRAPHIC
SNOW SHOWERS WILL BE POSSIBLE OVER THE SIERRA MADRE/MEDICINE BOW
RANGES. ANOTHER UPPER TROUGH TRACKS EAST ACROSS THE PACIFIC NORTHWEST
MONDAY MORNING THEN SOUTHEAST THROUGH WY MONDAY NIGHT. THIS SYSTEM
WILL BE ACCOMPANIED BY A COLD FRONT. MID/UPPER LEVEL DYNAMICS AND
MOISTURE APPEAR MORE ORGANIZED FOR SOME LIGHT PRECIPITATION OVER
SOUTH/EAST CENTRAL WY AND NORTHERN NE PANHANDLE. WEST-NORTHWEST
DOWNSLOPE WILL KEEP SOUTHEAST WY AND SOUTHERN NE PANHANDLE DRY. IT
WILL BE BREEZY MONDAY AND MONDAY NIGHT PRIOR TO AND AFTER FROPA.
LIGHT SNOW WILL GRADUALLY END DURING THE DAY TUESDAY FOLLOWING THE
PASSAGE OF THE UPPER TROUGH. IT WILL TURN COOLER TUESDAY WITH HIGH
TEMPERATURES CLOSER TO SEASONAL NORMALS IN THE 20S AND 30S. BREEZY
NORTHWEST WINDS WILL PREVAIL AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 230 AM MST WED JAN 14 2015
PER LATEST HRRR MODEL GUIDANCE...MVFR TO LIFR CIGS WILL LINGER THIS
MORNING WEST OF THE LARAMIE RANGE. OCCASIONAL MVFR CIGS WILL OCCUR
FROM LARAMIE TO CHEYENNE AS WELL. VSBYS MAY BRIEFLY DROP TO MVFR AT
RAWLINS AND SARATOGA...WITH IFR TO LIFR VSBYS OVER THE SOUTHERN
LARAMIE RANGE. ELSEWHERE...EXPECT VFR CONDITIONS THROUGH THE FORECAST
PERIOD. LIGHT AND VARIABLE WINDS EARLY THIS MORNING WILL BECOME
SOUTHWESTERLY 10-15 KT...WITH GUSTS TO 20 KT LATE THIS MORNING ALONG
AND WEST OF THE LARAMIE RANGE.
&&
.FIRE WEATHER...
ISSUED AT 230 AM MST WED JAN 14 2015
NO FIRE WEATHER CONCERNS. WITH SNOW STILL ON THE GROUND ACROSS MUCH
OF THE AREA...OVERALL CONDITIONS WILL NOT SUPPORT NOTABLE FIRE GROWTH
OVER THE NEXT FEW DAYS. MUCH WARMER TEMPERATURES ARE EXPECTED BY LATE
IN THE WEEK...WITH WINDY CONDITIONS ALONG AND WEST OF THE LARAMIE
RANGE. AFTERNOON RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE 25 PERCENT
THROUGH THE END OF THE WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...CLH
LONG TERM...MAJ
AVIATION...MAJ
FIRE WEATHER...CLH