Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/07/15
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1017 AM MST SAT DEC 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM MST SAT DEC 5 2015
AN UPPER LEVEL TROF WILL BE MOVING ACROSS THE STATE TODAY. THIS
SYSTEM WILL BRING SOME SNOW TO THE CONTDVD THRU THE DAY...WITH THE
BEST CHANCES BEING OVER THE CENTRAL MTNS. SNOW ACCUMULATIONS ALONG
THE CONTDVD WILL BE LIGHT...WITH MAYBE 2-3 INCHES OVR THE CENTRAL
MTNS. PCPN WILL SPREAD EASTWARD TODAY...WITH LIGHT SNOW
ACCUMULATIONS EXPECTED OVER THE EASTERN MTNS...MAINLY THIS
AFTERNOON. BY LATE MORNING A COLD FRONT WILL MOVE INTO EL PASO
COUNTY AND THEN CONTINUE SOUTHWARD THRU THE PLAINS THRU THE EARLY
AFTERNOON...BRINGING GUSTY NORTHERLY WINDS TO THE AREA. THE FORECAST
MODELS HAVE BEEN CONSISTENT IN BRINGING PCPN TO EL PASO AND TELLER
COUNTIES LATE THIS MORNING AND THIS AFTERNOON. THE NAM AND HRRR ALSO
SHOW THE POTENTIAL FOR SOME ISOLD PCPN ALONG THE I-25 CORRIDOR OVR
PUEBLO...HUERFANO AND WRN LAS ANIMAS COUNTIES. LOOKS LIKE LITTLE
CHANCE FOR PCPN OVR THE FAR SERN PLAINS. TEMPS WILL BE COOLER
TODAY...BUT HIGHS SHOULD GENERALLY STILL BE A LITTLE ABOVE AVERAGE.
THE UPR TROF MOVES OUT OF THE STATE IN THE EARLY EVENING HOURS...AND
BY LATE EVENING PCPN CHANCES SHOULD END WITH CLEARING SKIES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM MST SAT DEC 5 2015
OVERALL...IT STILL APPEARS THAT A MILD AND RELATIVELY DRY METEOROLOGICAL
PATTERN SHOULD BE NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT
DURING THE BALANCE OF THE LONGER TERM...ALTHOUGH INCREASING
PRECIPITATION CHANCES ARE ANTICIPATED BY LATER IN THE WEEK AS A
SYSTEM IMPACTS THE REGION.
MAIN METEOROLOGICAL ISSUES DURING THE LONGER TERM WILL BE
TEMPERATURES...THE POTENTIAL FOR GUSTY WINDS AT TIMES AND
POPS(ESPECIALLY BY LATER IN THE WEEK).
THE DRY UPPER RIDGING PATTERN OF SUNDAY WILL TRANSITION TO A DRY
ZONAL TO NORTHWESTERLY UPPER FLOW PATTERN FROM SUNDAY NIGHT INTO
AT LEAST WEDNESDAY EVENING.
THEN...AN UPPER SYSTEM APPROACHING THE FORECAST DISTRICT BY LATE
WEEK WILL BRING THE POTENTIAL FOR UNSETTLED METEOROLOGICAL
CONDITIONS BY LATER NEXT WEEK(ESPECIALLY OVER PORTIONS OF THE
CENTRAL AND WESTERN MOUNTAINS).
IN ADDITION...VARYING DEGREES OF EASTERN COLORADO SURFACE LEE-SIDE
TROUGHING IS ANTICIPATED FROM SUNDAY INTO FRIDAY WITH THE
POTENTIAL FOR A NORTHERLY SURGE MOVING ACROSS EASTERN SECTIONS
DURING FRIDAY EVENING/NIGHT.
THE HIGHEST POTENTIAL FOR STRONGER GRADIENT WINDS DURING THE
LONGER TERM SHOULD BE NOTED FROM THURSDAY INTO NEXT WEEKEND.
IN REGARDS TO TEMPERATURES...GENERALLY ABOVE SEASONAL EARLY TO
MID-DECEMBER TEMPERATURES ARE PROJECTED FROM SUNDAY INTO FRIDAY
WITH COOLER TEMPERATURES ANTICIPATED BY NEXT SATURDAY. AT THIS
TIME...IT APPEARS THAT THE WARMEST CONDITIONS DURING THE LONGER
TERM SHOULD BE REALIZED FROM MONDAY INTO WEDNESDAY...WITH COOLEST
READINGS EXPECTED BY FRIDAY AND ESPECIALLY NEXT SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1005 AM MST SAT DEC 5 2015
A COOL FRONT WILL MOVE ACROSS KPUB AND KPUB AT THIS TIME. WINDS
WILL TAKE ON A NORTHERLY COMPONENT AND MAY BE A BIT GUSTY AT
TIMES. A FEW ISOLATED SHOWERS WILL ALSO BE POSSIBLE. WINDS WILL
BECOME LIGHT NORTHWESTERLY BY SUNSET. OVERALL...EXPECT VFR
CONDITIONS AT KPUB AND KCOS...BUT THERE MAY BE A VERY BRIEF PD OF
MVFR IF ANY HEAVY SNOW SHOWER DEVELOPS.
AT KALS...VFR CONDITIONS ARE ANTICIPATED.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AVIATION...HODANISH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
458 AM MST SAT DEC 5 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM MST SAT DEC 5 2015
AN UPPER LEVEL TROF WILL BE MOVING ACROSS THE STATE TODAY. THIS
SYSTEM WILL BRING SOME SNOW TO THE CONTDVD THRU THE DAY...WITH THE
BEST CHANCES BEING OVER THE CENTRAL MTNS. SNOW ACCUMULATIONS ALONG
THE CONTDVD WILL BE LIGHT...WITH MAYBE 2-3 INCHES OVR THE CENTRAL
MTNS. PCPN WILL SPREAD EASTWARD TODAY...WITH LIGHT SNOW
ACCUMULATIONS EXPECTED OVER THE EASTERN MTNS...MAINLY THIS
AFTERNOON. BY LATE MORNING A COLD FRONT WILL MOVE INTO EL PASO
COUNTY AND THEN CONTINUE SOUTHWARD THRU THE PLAINS THRU THE EARLY
AFTERNOON...BRINGING GUSTY NORTHERLY WINDS TO THE AREA. THE FORECAST
MODELS HAVE BEEN CONSISTENT IN BRINGING PCPN TO EL PASO AND TELLER
COUNTIES LATE THIS MORNING AND THIS AFTERNOON. THE NAM AND HRRR ALSO
SHOW THE POTENTIAL FOR SOME ISOLD PCPN ALONG THE I-25 CORRIDOR OVR
PUEBLO...HUERFANO AND WRN LAS ANIMAS COUNTIES. LOOKS LIKE LITTLE
CHANCE FOR PCPN OVR THE FAR SERN PLAINS. TEMPS WILL BE COOLER
TODAY...BUT HIGHS SHOULD GENERALLY STILL BE A LITTLE ABOVE AVERAGE.
THE UPR TROF MOVES OUT OF THE STATE IN THE EARLY EVENING HOURS...AND
BY LATE EVENING PCPN CHANCES SHOULD END WITH CLEARING SKIES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 458 AM MST SAT DEC 5 2015
OVERALL...IT STILL APPEARS THAT A MILD AND RELATIVELY DRY METEOROLOGICAL
PATTERN SHOULD BE NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT
DURING THE BALANCE OF THE LONGER TERM...ALTHOUGH INCREASING
PRECIPITATION CHANCES ARE ANTICIPATED BY LATER IN THE WEEK AS A
SYSTEM IMPACTS THE REGION.
MAIN METEOROLOGICAL ISSUES DURING THE LONGER TERM WILL BE
TEMPERATURES...THE POTENTIAL FOR GUSTY WINDS AT TIMES AND
POPS(ESPECIALLY BY LATER IN THE WEEK).
THE DRY UPPER RIDGING PATTERN OF SUNDAY WILL TRANSITION TO A DRY
ZONAL TO NORTHWESTERLY UPPER FLOW PATTERN FROM SUNDAY NIGHT INTO
AT LEAST WEDNESDAY EVENING.
THEN...AN UPPER SYSTEM APPROACHING THE FORECAST DISTRICT BY LATE
WEEK WILL BRING THE POTENTIAL FOR UNSETTLED METEOROLOGICAL
CONDITIONS BY LATER NEXT WEEK(ESPECIALLY OVER PORTIONS OF THE
CENTRAL AND WESTERN MOUNTAINS).
IN ADDITION...VARYING DEGREES OF EASTERN COLORADO SURFACE LEE-SIDE
TROUGHING IS ANTICIPATED FROM SUNDAY INTO FRIDAY WITH THE
POTENTIAL FOR A NORTHERLY SURGE MOVING ACROSS EASTERN SECTIONS
DURING FRIDAY EVENING/NIGHT.
THE HIGHEST POTENTIAL FOR STRONGER GRADIENT WINDS DURING THE
LONGER TERM SHOULD BE NOTED FROM THURSDAY INTO NEXT WEEKEND.
IN REGARDS TO TEMPERATURES...GENERALLY ABOVE SEASONAL EARLY TO
MID-DECEMBER TEMPERATURES ARE PROJECTED FROM SUNDAY INTO FRIDAY
WITH COOLER TEMPERATURES ANTICIPATED BY NEXT SATURDAY. AT THIS
TIME...IT APPEARS THAT THE WARMEST CONDITIONS DURING THE LONGER
TERM SHOULD BE REALIZED FROM MONDAY INTO WEDNESDAY...WITH COOLEST
READINGS EXPECTED BY FRIDAY AND ESPECIALLY NEXT SATURDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 458 AM MST SAT DEC 5 2015
VFR CONDITIONS ARE EXPECTED AT KALS AND KPUB TODAY. KPUB MAY SEE
SOME SHOWERS IN THE VCNTY THIS AFTERNOON BUT CHANCES ARE TOO LOW TO
INCLUDE IN THE TAF. KCOS WILL SEE CIGS LOWER AND THERE WILL BE THE
CHANCE FOR SOME PCPN IN THE AREA BY AROUND 18Z AND CONTINUING INTO
THE EARLY EVENING HOURS. IT IS POSSIBLE THAT PCPN AT KCOS COULD
CAUSE BRIEF MVFR CONDITIONS THIS AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
455 AM EST SAT DEC 5 2015
.DISCUSSION...
...WINDY WITH ROUGH SURF AND HAZARDOUS BOATING CONDITIONS THIS
WEEKEND...
TODAY-TONIGHT...
H30-H20 JET STREAK LIFTING OFF THE SE SEABOARD WILL PULL A DEEP HI
PRES RIDGE ACRS THE ERN CONUS. THE BASE OF THE RIDGE WILL INTERACT
WITH A WEAK FRONTAL TROF OVER S FL AND THE NRN BAHAMAS TO GENERATE A
BRISK NE FLOW ACRS CENTRAL FL. THE USAF 915HZ PROFILER HAS BEEN
MEASURING 25-30KT WINDS THRU THE H100-H85 LYR...BACKING TO THE W/SW
THRU THE H85-H70 LYR. THIS INDICATES INCREASED POTENTIAL FOR
ISENTROPIC LIFT...CONFIRMED BY LATEST RUC ANALYSIS.
FRONTAL MOISTURE BAND HAS PUSHED INTO S FL WITH PWAT VALUES ARND
2.1" AT KMFL/KEYW. MOISTURE PROFILE DECREASES NWD AS AN H85-H50
CYCLONE OVER THE DEEP SOUTH HAS BEGUN TO PUSH DRIER MID LVL AIR INTO
CENTRAL FL. PWATS DECREASE TO ARND 1.5" AT KXMR/KTBW...THEN TO ARND
1.0" AT KJAX. RADAR HAS BEEN DETECTING BANDS OF LIGHT SHRAS PUSHING
ONSHORE FROM SEBASTIAN INLET SWD....BUT NONE ARE MAKING IT INTO THE
INTERIOR.
AS THE JET STREAK LIFTS OUT OF THE AREA...IT WILL KEEP THE S HALF OF
THE PENINSULA UNDER ITS ASCENDING RIGHT REAR QUAD. MEANWHILE...THE
MID LVL ISENTROPIC LIFT AND ENHANCED LOW LVL CONVERGENCE IN THE
VCNTY OF THE FRONT WILL PROVIDE SUFFICIENT DYNAMIC SUPPORT TO KEEP
50/60 POPS IN FOR THE TREASURE COAST AND LAKE OKEECHOBEE AREA. POPS
DECREASING TO 30-40PCT FROM BREVARD/OSCEOLA COUNTY NWD TO REFLECT
THE DECREASING MOISTURE. DRY MID LVL AIR WILL ADVECT ACRS THE CWA
OVERNIGHT AS THE TROF OVER THE DEEP S DRIFTS OFF THE CAROLINA
COAST... POPS DROPPING TO 30PCT TREASURE COAST...AOB 20PCT
ELSEWHERE. PRECIP PRIMARILY WILL BE IN THE FORM OF BRIEF LOW TOPPED
SHRAS. LOW RAINFALL POTENTIAL WITH 24HR QPF BTWN 0.10"-0.25" ALONG
THE TREASURE COAST...AOB 0.10" ELSEWHERE.
NO SIG CHANGE IN AIRMASS WITH THE PERSISTENT NE FLOW...TEMPS NOT
EXPECTED TO DEVIATE MORE THAN A DEG OR TWO FROM FRI. AFTN MAXES IN
THE M/U70S WITH A FEW SPOTS TOUCHING 80F...MIN TEMPS MIN TEMPS
L/M60S INTERIOR AND U60S/L70S ALONG THE COAST. COASTAL COUNTIES NOT
EXPECTED TO SEE TEMPS FLUCTUATE BY MORE THAN 10F.
SUN-TUE...PROGRESSIVE SPLIT FLOW FLOW PATTERN CONTINUES OVER THE
CONUS WITH SHORT WAVE TROUGHS IN THE NORTHERN STREAM REMAINING WELL
NORTH OF FL A WEAKER SRN BRANCH IS BECOMING BETTER ESTABLISHED...
BUT HAS LITTLE IN THE WAY OF DISCRETE DISTURBANCES POISED TO IMPACT
THE STATE.
AN AMPLIFIED TROUGH PUSHES THROUGH THE MS VLY SUN...THE OH VLY MON
AND OFFSHORE THE EASTERN SEABOARD TUE. THIS WILL INDUCE SFC WAVE
DEVELOPMENT OFFSHORE THE CAROLINAS LATE MON...WHICH UNDERGOES FAIRLY
RAPID INTENSIFICATION WELL OFFSHORE THE MID ATLC/NERN CONUS AS IT
MOVES ENE. THE GFS/ECM ARE IN RESPECTABLE AGREEMENT WITH LOCATION/
INTENSITY OF THE LOW AND ITS IMPACTS ON FL. STRONG ONSHORE WINDS
SUNDAY WILL GRADUALLY EASE AND BACK TO NRLY SUN NIGHT-EARLY MON AS
AN INVERTED TROUGH FORMS OFF THE FL EAST COAST. AS THE LOW LIFTS
QUICKLY NEWD...HIGH PRES AND BRIEF SHOT OF COOLER/DRIER AIR WILL
POUR SWD INTO FL FROM LATE MON INTO TUE....BEFORE WINDS VEERING TO
ONSHORE TUE AFTN-EVENING START TO SLOWLY MODIFY THE LOCAL AIR MASS.
BREEZY TO WINDY CONDITIONS START TO EASE MON AND EVEN MORESO TUE.
PRECIP REGIME WILL CONSIST OF FAST-MOVING LOW TOPPED SHOWERS...
MOSTLY LIGHT...WITH RAIN CHCS RETREATING TWD THE COAST/SEAWARD AS
WINDS BACK FOR A TIME. MAX TEMPS IN THE U70S-NEAR 80F SUN WITH
MINS MAINLY IN THE M-U60S...SOME L70S ALONG THE BARRIER ISLANDS.
M-U70S FOR HIGHS MON (SOME L70S COASTAL VOLUSIA). INLAND MINS DROP
INTO THE M-U50S MONDAY NIGHT AS BACKING WINDS WILL SUPPORT STEADY
COOL AIR ADVECTION. HOWEVER BLYR WINDS AVG 360DEG...WHICH IS ABOUT
15-20 DEGREES OF ONSHORE COMPONENT. THIS WILL RESULT IN A SHARP TEMP
GRADIENT FOR MAINLAND VS BARRIER ISLANDS OF THE COASTAL COS.
SLIGHTLY COOLER OVERALL FOR TUE...L-M70S NORTH...M-U70S SOUTH FOR
MAXES. MINS M-U50S INLAND...WITH SOME L50S FAR NORTH...GENERALLY
L-M60S OR THE COAST.
WED-FRI...WEAK HIGH PRES RIDGE AXIS WILL SETTLE ACROSS SRN MS/AL/GA
AND NRNMOST FL WED-WED NIGHT...WHICH WILL KEEP CTRL FL IN A LIGHT
ONSHORE FLOW REGIME WITH GENERALLY DRY CONDITIONS SAVE FOR A SLIGHT
CHANCE OF SHOWERS FOR THE LAKE O/TREASURE COAST REGION. BY THU...AS
WAS THE CASE 24HRS AGO...THE GLOBAL MODELS SHOW VERY DIVERGENT SOLNS
W/R/T A MID LEVEL SHORT WAVE TROUGH IN THE SRN STREAM IMPACTING FL
LATE NEXT WEEK. THE ECM IS MUCH FASTER WITH THIS FEATURE...BRINGING
A FAST-MOVING FLAT/POS TILT FEATURE ACROSS THE STATE THU NIGHT...
WHICH KEEPS MOST IF NOT ALL OF THE PRECIP SOUTH/EAST OF CTRL FL.
AT THE SAME TIME THE ECM HAS THE TROUGH OVER CTRL/SOUTH FL...THE GFS
IS LAGGING THIS FEATURE WELL TO THE WEST (JUST OFFSHORE THE SOUTH TX
COAST) BEFORE SHEARING IT OUT FRI-FRI NIGHT AS IT KICKS ENE-WD OVER
THE GOMEX AND OVER FL BY FRIDAY NIGHT.
HENCE...THE ECM POINTS TO CONT`D DRY WX FOR THU-FRI...WHILE THE GFS
SLOWLY INCREASES RAIN CHCS...ESPECIALLY FRI OVER THE SRN CWA. AS IS
THE CASE WITH FAST/ZONAL FLOW...SPECIFIC MODEL-ADVERTISED DETAILS IN
THE XTD RANGE (DAYS 5-7) WHICH HAVE ALREADY SHOWN CHANGES FROM FRI
AM ARE VERY LIKELY TO CONTINUE HAVING CONTINUITY PROBLEMS. THUS...THE
CURRENT FCST COMMITS TO NEITHER SOLUTION AND PAINTS SMALL RAIN CHCS
FOR BOTH DAYS. TEMPS WILL REMAIN ABOVE AVERAGE THROUGH THE PERIOD.
EARLY DECEMBER NORMAL MAXES FOR ECFL ARE L70S NORTH AND M-U70S SOUTH
WITH MINS IN THE L-M50S,,,EXCEPT U50S ALONG THE MARTIN COUNTY COAST.
&&
.AVIATION...THRU 06/12Z.
SFC WNDS: THRU 05/15Z...N/NE 7-12KTS...OCNL G20KTS CSTL SITES N OF
KVRB. BTWN 05/15Z-06/03Z...E/NE ARND 15-20KTS WITH G22-25KTS. AFT
06/03Z...N/NE 10-13KTS...OCNL G22KTS COASTAL SITES.
VSBY/WX/CIGS: THRU 05/14Z...N OF KISM-KDAB PREVAILING CIGS BTWN
FL006-009...S OF KISM-KMLB PREVAILING CIGS BTWN FL060-080 WITH BRIEF
ISOLD MVFR SHRAS. BTWN 05/14Z-05/24Z...PREVAILING CIGS BTWN
FL040-060...MVFR -SHRAS LIKELY BTWN KVRB-KSUA...CHC MVFR -SHRAS
ELSEWHERE. AFT 06/00Z...PREVAILING CIGS BTWN FL040-060...CHC MVFR
SHRAS BTWN KVRB-KSUA...SLGT CHC MVFR -SHRAS ELSEWHERE.
&&
.MARINE...
TODAY-TONIGHT...HAZARDOUS BOATING CONDITIONS TO CONTINUE. A LARGE
HI PRES RIDGE BLANKETING THE ERN CONUS WILL INTERACT WITH A FRONTAL
TROF OVER S FL TO GENERATE A FRESH TO STRONG NE BREEZE OVER THE
LCL ATLC. DATA BUOYS MEASURING 5-8FT SEAS NEARSHORE AND 9-12FT
OFFSHORE WITH DOMINANT PDS BTWN 8-9SEC. GUSTS NEAR GALE FORCE
EXPECTED OVER THE OFFSHORE WATERS. NO CHANGES TO THE CURRENT SCA.
SUN-MON...STOUT ONSHORE (NE-ENE) WINDS WILL PREVAIL AGAIN SUNDAY
BEFORE RELENTING SUNDAY EVENING/OVERNIGHT AS AN INVERTED TROUGH
DEVELOPS EAST OF FL. LOW SPINNING UP WELL TO THE NE WILL RESULT
IN BRIEF INCREASE IN NRLY WINDS MON/MON NIGHT WHICH COULD BRIEFLY
KICK WINDS BACK UP TO AROUND 20KT. AT THE VERY LEAST...EXPECT
CAUTIONARY CONDITIONS TO CONTINUE ONCE THE SCA EXPIRES.
TUE-WED...WINDS SLACKEN FROM 10-15KT TO AOB 10KT AS THEY VEER FROM
NE TO E. CONSEQUENTLY...SEAS WILL SUBSIDE TO 3-4FT IN A SMALL
LINGERING SWELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 76 67 76 65 / 40 20 30 30
MCO 80 66 79 65 / 30 20 20 20
MLB 79 73 79 69 / 40 20 30 30
VRB 78 74 79 69 / 50 30 40 40
LEE 78 62 78 61 / 30 10 20 10
SFB 78 65 78 64 / 30 20 20 20
ORL 79 66 79 64 / 30 20 20 20
FPR 79 73 79 70 / 60 30 40 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR COASTAL VOLUSIA COUNTY-INDIAN RIVER-MARTIN-
NORTHERN BREVARD COUNTY-SOUTHERN BREVARD COUNTY-ST. LUCIE.
HIGH SURF ADVISORY UNTIL 4 PM EST SUNDAY FOR COASTAL VOLUSIA
COUNTY-INDIAN RIVER-MARTIN-NORTHERN BREVARD COUNTY-SOUTHERN
BREVARD COUNTY-ST. LUCIE.
AM...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 0-20 NM-FLAGLER BEACH TO
VOLUSIA-BREVARD COUNTY LINE 20-60 NM-SEBASTIAN INLET TO
JUPITER INLET 0-20 NM-SEBASTIAN INLET TO JUPITER INLET 20-
60 NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 0-20
NM-VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 20-60 NM.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX....CRISTALDI
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1031 PM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
WEAKEN AS A TROUGH INTENSIFIES OFF THE COAST TONIGHT. THE LOW
PRESSURE WILL MOVE NORTHEASTWARD AND FARTHER AWAY FROM THE
FORECAST AREA MONDAY. MUCH OF THE MOISTURE WITH THE COASTAL SYSTEM
WILL REMAIN EAST OF THE FORECAST AREA. PRESSURE RIDGING WILL BE
IN THE REGION TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WATER VAPOR IMAGERY THIS EVENING SHOWS AN UPPER TROUGH MOVING
EAST ACROSS THE OHIO VALLEY WITH SOUTHWESTERLY 500MB FLOW OVER
THE FORECAST AREA. SURFACE HIGH PRESSURE CENTERED OVER THE MID
ATLANTIC CONTINUES TO RIDGE INTO THE CAROLINAS WHILE A WEAK
INVERTED TROUGH WAS TAKING SHAPE JUST OFF THE COAST. LATEST RADAR
IMAGERY LOOP SHOWS SOME LIGHT SHOWERS OCCURRING ALONG THE COAST
BUT LITTLE IF ANY IS REACHING THE SURFACE WITH NO SURFACE
OBSERVATIONS REPORTING ANY PRECIPITATION.
UPWARD VERTICAL MOTION INCREASES LATER TONIGHT OVER THE FORECAST
AREA ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF AN UPPER JET
ROUNDING THE BASE OF THE UPPER TROUGH...INDUCING CYCLOGENESIS OFF
THE COAST. MOST OF THE MODEL GUIDANCE SUITE IS SHOWING SHOWERS
DEVELOP ALONG THE COASTAL PLAIN AND REACHING INTO THE EASTERN
MIDLANDS AFTER 06Z AND THEN SLOWLY SHIFTING NORTHWARD WITH TIME.
WILL CONTINUE TO CARRY THE STRONG GRADIENT IN POPS WITH LOW
LIKELY POPS FAR EAST TO DRY IN THE WEST. MORE CLOUDS IN THE EAST
SHOULD HELP HOLD UP TEMPERATURES TONIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
MOISTURE ASSOCIATED WITH THE COASTAL TROUGH SHOULD BE MAINLY
CONFINED TO THE EAST PART OF THE FORECAST AREA EARLY MONDAY. THE
MODELS INDICATE UPPER-LEVEL LIFT ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF THE H25 JET SHIFTING EAST OF THE FORECAST AREA
EARLY. LEANED TOWARD THE SREF MEAN FOR THE POP FORECAST WHICH WAS
CLOSE TO NAM AND GFS MOS. THE NAM...GFS...ECMWF...AND SREF MEAN
INDICATE RAIN AMOUNTS OF 0.25 OF AN INCH OR LESS. THE MODELS SHOW
MOISTURE DIMINISHING MONDAY AFTERNOON AS THE SYSTEM SHIFTS
FARTHER NORTHEASTWARD. THE PRESSURE RIDGE MOVING INTO THE FORECAST
AREA IN THE WAKE OF THE COASTAL SYSTEM SHOULD EXTEND THROUGH THE
FORECAST AREA TUESDAY AND TUESDAY NIGHT. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST EXCEPT STRONG NET
RADIATIONAL COOLING FAVORS THE COOLER GUIDANCE TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY SURFACE RIDGING DOMINATING DURING MUCH
OF THE MEDIUM-RANGE PERIOD. THE MODELS DEPICT JUST A GLANCING
BRUSH OF THE NEXT TROUGH PROGGED TO MOVE ACROSS THE NORTHEAST PART
OF THE NATION WEDNESDAY NIGHT. THE MODELS SHOW MOST OF THE LIFT
ASSOCIATED WITH A WARM FRONT REMAINING NORTH OF THE FORECAST AREA
FRIDAY AND SATURDAY. THE MODELS INDICATE A COLD FRONT MAY BRING
SHOWERS SUNDAY. THE GFS...ECMWF...AND EKD MOS HAVE ABOVE NORMAL
TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
SURFACE HIGH PRESSURE CURRENTLY OVER THE MID ATLANTIC AND WESTERN
CAROLINAS WILL GRADUALLY WEAKEN TONIGHT AS A WEAK COASTAL TROUGH
DEVELOPS. LATEST REGIONAL RADAR LOOP INDICATING SOME LIGHT
SHOWERS OFF THE SC COAST THIS EVENING. LATEST HRRR DEPICTING SOME
LIGHT RAIN MOVING INLAND AS FAR WEST AS THE EASTERN MIDLANDS
DURING THE OVERNIGHT HOURS...WHICH MAY AFFECT OGB GIVEN LATEST
SURFACE OBS. HAVE INCLUDED MENTION OF -RA FOR OGB FOR THE
OVERNIGHT ALONG WITH MVFR CIGS. AGS/DNL MAY ALSO HAVE SOME MVFR
CIGS OVERNIGHT AS WELL...AND CANNOT RULE OUT -RA AS WELL. SOME
THIN CIRRUS COULD CONTINUE TO STREAM OVERHEAD...WITH SOME
ADDITIONAL MID LEVEL CLOUDINESS WELL TO OUR WEST POSSIBLY
STREAMING IN LATE TONIGHT. EXPECT VFR AT ALL TAF SITES BY 15Z
MONDAY. CLOUDS SHOULD BEGIN TO THIN OUT BY LATE IN THE DAY AS THE
COASTAL TROUGH LIFTS TO THE NE.
EXTENDED AVIATION OUTLOOK...FOG POSSIBLE AT THE FOG PRONE SITES
AGS/OGB EARLY TUESDAY MORNING. OTHERWISE...NO SIGNIFICANT IMPACTS
TO AVIATION EXPECTED THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
814 PM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
WEAKEN AS A TROUGH INTENSIFIES OFF THE COAST TONIGHT. THE LOW
PRESSURE WILL MOVE NORTHEASTWARD AND FARTHER AWAY FROM THE
FORECAST AREA MONDAY. MUCH OF THE MOISTURE WITH THE COASTAL SYSTEM
WILL REMAIN EAST OF THE FORECAST AREA. PRESSURE RIDGING WILL BE
IN THE REGION TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WATER VAPOR IMAGERY THIS EVENING SHOWS AN UPPER TROUGH MOVING
EAST ACROSS THE OHIO VALLEY WITH SOUTHWESTERLY 500MB FLOW OVER
THE FORECAST AREA. SURFACE HIGH PRESSURE CENTERED OVER THE MID
ATLANTIC CONTINUES TO RIDGE INTO THE CAROLINAS WHILE A WEAK
INVERTED TROUGH WAS TAKING SHAPE JUST OFF THE COAST. LATEST RADAR
IMAGERY LOOP SHOWS SOME LIGHT SHOWERS OCCURRING ALONG THE COAST
BUT LITTLE IF ANY IS REACHING THE SURFACE WITH NO SURFACE
OBSERVATIONS REPORTING ANY PRECIPITATION.
UPWARD VERTICAL MOTION INCREASES LATER TONIGHT OVER THE FORECAST
AREA ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF AN UPPER JET
ROUNDING THE BASE OF THE UPPER TROUGH...INDUCING CYCLOGENESIS OFF
THE COAST. MOST OF THE MODEL GUIDANCE SUITE IS SHOWING SHOWERS
DEVELOP ALONG THE COASTAL PLAIN AND REACHING INTO THE EASTERN
MIDLANDS AFTER 06Z AND THEN SLOWLY SHIFTING NORTHWARD WITH TIME.
WILL CONTINUE TO CARRY THE STRONG GRADIENT IN POPS WITH LOW
LIKELY POPS FAR EAST TO DRY IN THE WEST. MORE CLOUDS IN THE EAST
SHOULD HELP HOLD UP TEMPERATURES TONIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
MOISTURE ASSOCIATED WITH THE COASTAL TROUGH SHOULD BE MAINLY
CONFINED TO THE EAST PART OF THE FORECAST AREA EARLY MONDAY. THE
MODELS INDICATE UPPER-LEVEL LIFT ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF THE H25 JET SHIFTING EAST OF THE FORECAST AREA
EARLY. LEANED TOWARD THE SREF MEAN FOR THE POP FORECAST WHICH WAS
CLOSE TO NAM AND GFS MOS. THE NAM...GFS...ECMWF...AND SREF MEAN
INDICATE RAIN AMOUNTS OF 0.25 OF AN INCH OR LESS. THE MODELS SHOW
MOISTURE DIMINISHING MONDAY AFTERNOON AS THE SYSTEM SHIFTS
FARTHER NORTHEASTWARD. THE PRESSURE RIDGE MOVING INTO THE FORECAST
AREA IN THE WAKE OF THE COASTAL SYSTEM SHOULD EXTEND THROUGH THE
FORECAST AREA TUESDAY AND TUESDAY NIGHT. USED THE GUIDANCE
CONSENSUS FOR THE TEMPERATURE FORECAST EXCEPT STRONG NET
RADIATIONAL COOLING FAVORS THE COOLER GUIDANCE TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE GFS AND ECMWF DISPLAY SURFACE RIDGING DOMINATING DURING MUCH
OF THE MEDIUM-RANGE PERIOD. THE MODELS DEPICT JUST A GLANCING
BRUSH OF THE NEXT TROUGH PROGGED TO MOVE ACROSS THE NORTHEAST PART
OF THE NATION WEDNESDAY NIGHT. THE MODELS SHOW MOST OF THE LIFT
ASSOCIATED WITH A WARM FRONT REMAINING NORTH OF THE FORECAST AREA
FRIDAY AND SATURDAY. THE MODELS INDICATE A COLD FRONT MAY BRING
SHOWERS SUNDAY. THE GFS...ECMWF...AND EKD MOS HAVE ABOVE NORMAL
TEMPERATURES THROUGH THE PERIOD.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
SURFACE HIGH PRESSURE CURRENTLY OVER THE MID ATLANTIC AND WESTERN
CAROLINAS WILL GRADUALLY WEAKEN TONIGHT. LATEST REGIONAL RADAR
LOOP INDICATING SOME LIGHT SHOWERS OFF THE SC COAST THIS EVENING.
LATEST HRRR DEPICTING SOME LIGHT RAIN MOVING INLAND AS FAR WEST AS
THE EASTERN MIDLANDS DURING THE OVERNIGHT HOURS...WHICH MAY AFFECT
OGB. HAVE INCLUDED MENTION OF VCSH FOR OGB FOR THE OVERNIGHT ALONG
WITH MVFR CIGS. THIS CLOUDINESS IS EXPECTED TO REMAIN EAST OF THE
CSRA...AGS/DNL...THOUGH SOME THIN CIRRUS COULD CONTINUE TO STREAM
OVERHEAD...WITH SOME ADDITIONAL MID LEVEL CLOUDINESS WELL TO OUR
WEST POSSIBLY STREAMING IN LATE TONIGHT. HOWEVER...SOME SLIGHT LOW
LEVEL MOISTURE RECOVERY...COUPLED WITH LIGHTER WINDS AND A PERIOD
OF MOSTLY CLEAR SKIES POSSIBLE TONIGHT FOR THE CSRA...INCLUDED A
TEMPO GROUP TONIGHT FOR MVFR VSBYS AT FOG PRONE AGS.
EXTENDED AVIATION OUTLOOK...FOG POSSIBLE AT THE FOG PRONE SITES
AGS/OGB EARLY TUESDAY MORNING. OTHERWISE...NO SIGNIFICANT IMPACTS
TO AVIATION EXPECTED THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
149 PM CST SAT DEC 5 2015
.UPDATE...1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL LOOK AT THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* VFR CONDS ARE EXPECTED TO QUICKLY REDUCE TO IFR SHORTLY AFT 02Z
AND LIKELY LASTING ALL NIGHT...POSSIBLY DIPPING TO VLIFR.
* SOUTH TO SOUTHWEST WINDS BETWEEN 4-8KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW STEADY EROSION OF THE
STRATUS LAYER THAT HAS BLANKETED NORTHERN IL/NORTHWEST IN
AIRFIELDS THIS MORNING...UNFORTUNATELY IT APPEARS DUE TO THE LACK
OF MIXING DRIER AIR TO THE SURFACE THAT THE STRATUS AND FOG WILL
REDEVELOP AGAIN TONIGHT AND PERSIST THROUGH SUNDAY MORNING.
CURRENT HI-RES GUIDANCE CONTINUES TO SUGGEST THAT AROUND 00-02Z
SHALLOW STRATUS AROUND 500-800FT AGL WILL REDEVELOP AND THEN TREND
DOWN TOWARDS 400-500FT AGL LATE TONIGHT THROUGH DAYBREAK SUNDAY.
HAVE REFLECTED THIS IN THE CURRENT TAF...BUT THE UNCERTAINTY
REMAINS WITH HOW LOW VSBYS WILL GO AS SOME THIN CIRRUS IS NOTED TO
LIFT NORTHEAST ACROSS NORTHERN IL OVERNIGHT AND COULD LIMIT THE
DEVELOPMENT OF FOG.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM/HIGH CONFIDENCE IN CIGS QUICKLY LOWERING...LOW CONFIDENCE
IN PRECISE TIMING OF IFR/LIFR CIGS.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1204 PM CST SAT DEC 5 2015
.UPDATE...
1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL LOOK AT THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* VFR CONDS ARE EXPECTED TO QUICKLY REDUCE TO IFR SHORTLY AFT 02Z
AND LIKELY LASTING ALL NIGHT...POSSIBLY DIPPING TO VLIFR.
* SOUTH TO SOUTHWEST WINDS BETWEEN 4-8KT.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW STEADY EROSION OF THE
STRATUS LAYER THAT HAS BLANKETED NORTHERN IL/NORTHWEST IN
AIRFIELDS THIS MORNING...UNFORTUNATELY IT APPEARS DUE TO THE LACK
OF MIXING DRIER AIR TO THE SURFACE THAT THE STRATUS AND FOG WILL
REDEVELOP AGAIN TONIGHT AND PERSIST THROUGH SUNDAY MORNING.
CURRENT HI-RES GUIDANCE CONTINUES TO SUGGEST THAT AROUND 00-02Z
SHALLOW STRATUS AROUND 500-800FT AGL WILL REDEVELOP AND THEN TREND
DOWN TOWARDS 400-500FT AGL LATE TONIGHT THROUGH DAYBREAK SUNDAY.
HAVE REFLECTED THIS IN THE CURRENT TAF...BUT THE UNCERTAINTY
REMAINS WITH HOW LOW VSBYS WILL GO AS SOME THIN CIRRUS IS NOTED TO
LIFT NORTHEAST ACROSS NORTHERN IL OVERNIGHT AND COULD LIMIT THE
DEVELOPMENT OF FOG.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM/HIGH CONFIDENCE IN CIGS QUICKLY LOWERING...LOW CONFIDENCE
IN PRECISE TIMING OF IFR/LIFR CIGS.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1154 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1103 AM CST SAT DEC 5 2015
Surface ridge moving off to the east, and the winds continue with
a southerly direction across Central Illinois. Low level moisture
trapped by the significant inversion off the surface has resulted
in another foggy day. Eastern half of the state is slow to improve
yet again this morning, with the I-55 corridor a bit patchy still
between Bloomington and Springfield. Some minor adjustments to the
grids for the fog, and dropping the max temps a little in the east
with the lack of sunshine.
&&
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilities
holding across our east throughout the afternoon. Our warmest
readings once again will be in the west where the mercury should
top out in the lower 50s, while roughly along and east of the I-55
corridor, afternoon highs will be mostly in the 40s, with a few
locations over east central IL just getting to 40 degree later
this afternoon.
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1138 AM CST SAT DEC 5 2015
Almost a total repeat of yesterday...Fog in the eastern half of
Illinois keeping CMI in VLIFR, DEC and BMI improving to LIFR, but
on the edge. At this point, SPI and PIA remain in VFR, and SPI may
end up seeing some patchy fog, but doubtful it will become
predominate or even enough to warrant a tempo. South/southeasterly
winds through the overnight, becoming more southerly, with the
ridge axis out to the east. Overnight, expect much of the same,
with the western terminals most likely to see breaks in the fog
just after dawn. But for now, do not see enough of a response with
the dewpoints to warrant tempos better than 1/2sm vis, at least
just before dawn. Will amend if the xover temps drop a few
degrees.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ038-042>046-
052>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...HJS
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1109 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1103 AM CST SAT DEC 5 2015
Surface ridge moving off to the east, and the winds continue with
a southerly direction across Central Illinois. Low level moisture
trapped by the significant inversion off the surface has resulted
in another foggy day. Eastern half of the state is slow to improve
yet again this morning, with the I-55 corridor a bit patchy still
between Bloomington and Springfield. Some minor adjustments to the
grids for the fog, and dropping the max temps a little in the east
with the lack of sunshine.
&&
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilities
holding across our east throughout the afternoon. Our warmest
readings once again will be in the west where the mercury should
top out in the lower 50s, while roughly along and east of the I-55
corridor, afternoon highs will be mostly in the 40s, with a few
locations over east central IL just getting to 40 degree later
this afternoon.
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 505 AM CST SAT DEC 5 2015
IFR TO VLIFR conditions are expected thru the morning hours before
a gradual improvement this afternoon, especially across our
western TAF sites. We have seen a temporary improvement in cigs
and vsbys at BMI and SPI but based on satellite and surface obs
to our east and south, it looks as if the cigs and vsbys will
come down again at both sites in the next hour or two. Forecast
soundings not offering much hope for any significant break in the
cigs late this morning into this afternoon with PIA and SPI seeing
the best chance for cigs to break for a time. Little change in the
air mass is expected as we head into the overnight hours with
the threat for fog and low cigs to redevelop again and hold into
the morning hours of Sunday. Surface winds will remain a non-
factor thru tonight with a south to southeast wind at 7 to
12 kts today, and from 5 to 10 kts tonight.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ038-042>046-
052>057-061>063-066>068-071>073.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1038 AM CST SAT DEC 5 2015
.UPDATE...
1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL LOOK AT THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PATCHY IFR CIG/VIS IN STRATUS/FOG QUICKLY LIFTING TO VFR.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT CONDITIONS IMPROVEMENT.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1037 AM CST SAT DEC 5 2015
.UPDATE...
1037 AM CST
WE HAVE ENDED THE DENSE FOG ADVISORY FOR MOST AREAS NORTH OF I80
IN ILLINOIS THIS MORNING...AND THE REST OF THE AREA WILL LIKELY BE
ABLE TO END AT THE CURRENT EXPIRATION TIME AT NOON. CONDITIONS
HAVE CLEARED UP RATHER QUICKLY ACROSS NORTHERN
ILLINOIS...ESPECIALLY NORTH OF I-88 AS OF THIS WRITING. IT APPEARS
LIKELY THAT THE NORTHERN AND WESTERN EDGES OF THIS CLOUD/FOG DECK
WILL CONTINUE TO SLOWLY DISSIPATE THROUGH THE AFTERNOON. THIS
COULD RESULT IN MY NORTHWESTERN INDIANA COUNTIES AND EAST CENTRAL
ILLINOIS COUNTIES BEING IN THE LOW CLOUDS FOR MOST OF THE
DAY...SIMILAR TO YESTERDAY.
CONSIDERING SKIES ARE CLEARING QUICK NORTH...I HAVE RAISE HIGHS THIS
AFTERNOON...AS THE AIRMASS OVER THE AREA SHOULD SUPPORT MILD
CONDITIONS WELL INTO THE 40S OUTSIDE OF THE CLOUDY AREAS.
THEREFORE...THE WARMEST CONDITIONS...NEAR 50 LOOK TO BE NORTH AND IN
CHICAGO...WITH COOLER CONDITIONS...ONLY IN THE UPPER 30S TO LOW 40S
IN MY SOUTHEASTERN AREAS. I HAVE UPDATED THE FORECAST TO LEAN IN
THIS DIRECTION.
ITS POSSIBLE THAT SOME FOG AND LOW CLOUDS COULD RETURN TONIGHT...BUT
I WILL ASSES THIS POTENTIAL THIS AFTERNOON.
KJB
&&
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PATCHY IFR CIG/VIS IN STRATUS/FOG QUICKLY LIFTING TO VFR.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT CONDITIONS IMPROVEMENT.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1013 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PATCHY IFR CIG/VIS IN STRATUS/FOG QUICKLY LIFTING TO VFR.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT CONDITIONS IMPROVEMENT.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
820 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* LIFR CIG/VIS IN STRATUS/FOG THROUGH AT LEAST MID
MORNING...BRIEF VLIFR VIS POSSIBLE EARLY.
* IMPROVEMENT TO IFR LIKELY BY MIDDAY...POSSIBLE CLEARING TO VFR
THIS AFTERNOON.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CURRENT LIFR/VLIFR CIG/VIS CONDITIONS AND IN IMPROVEMENT
TO IFR THROUGH MID/LATE MORNING. LOW IN EXACTLY HOW LOW VSBY
DROPS...BUT HIGH IN FALLING TO AT LEAST 1SM.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
558 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* LIFR CIG/VIS IN STRATUS/FOG THROUGH AT LEAST MID
MORNING...BRIEF VLIFR VIS POSSIBLE EARLY.
* IMPROVEMENT TO IFR LIKELY BY MIDDAY...POSSIBLE CLEARING TO VFR
THIS AFTERNOON.
* POTENTIAL FOR REDEVELOPMENT OR LOWERING OF IFR/LIFR STRATUS/FOG
AGAIN TONIGHT.
RATZER
//DISCUSSION...UPDATED 12Z...
STRATUS/FOG WHICH SPREAD ACROSS TERMINALS OVERNIGHT WILL REMAIN
THIS MORNING...WITH LIFR/VLIFR CONDITIONS GRADUALLY IMPROVING TO
IFR MID/LATE MORNING. WOULD EXPECT SOME EROSION AROUND THE EDGES
OF THE STRATUS DECK FROM MID-MORNING ON...THOUGH DEGREE OF
CLEARING LIKELY TO BE LIMITED THE FARTHER SOUTHEAST ONE GOES. IT
IS POSSIBLE SOME CLEARING EVEN TO VFR WILL OCCUR BY EARLY
AFTERNOON...MOST LIKELY AT RFD NEAR THE EDGE OF THE CLOUD DECK.
EVEN IF CIGS LINGER...WILL LIKELY SEE A DIURNAL RISE TO CIGS AND A
SIGNIFICANT IMPROVEMENT IN VIS. TOUGH QUESTION IS WHAT OCCURS
TONIGHT...AS CLEARING WOULD LIKELY SET THE STAGE FOR SOME
NORTHWARD REDEVELOPMENT SIMILAR TO LAST NIGHT...AND IF A CEILING
LINGERS LIKELY A DIURNAL LOWERING OF VIS/CIG. THUS WHILE GENERAL
TREND OF FORECAST IS FAIRLY GOOD CONFIDENCE...SPECIFIC DETAILS IN
TIMING AND EXACT CIG HEIGHTS/VIS REMAIN RATHER LOW.
WINDS WILL REMAIN GENERALLY SOUTHERLY...BETWEEN ABOUT 200-170 DEG
AND 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH IN CURRENT LIFR/VLIFR CIG/VIS CONDITIONS AND IN IMPROVEMENT
TO IFR THROUGH MID/LATE MORNING. LOW IN EXACTLY HOW LOW VSBY
DROPS...BUT HIGH IN FALLING TO AT LEAST 1SM.
* LOW IN TIMING IMPROVEMENT TODAY...AND TRENDS TONIGHT.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH TUESDAY...PRIMARILY VFR. SMALL DAY TO DAY
CHANCE OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
WEDNESDAY...SLIGHT CHANCE -RA/MVFR.
THURSDAY...VFR/MVFR CIGS.
FRIDAY...SLIGHT CHANCE -RA AND MVFR/IFR.
RATZER
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
508 AM CST SAT DEC 5 2015
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilities
holding across our east throughout the afternoon. Our warmest
readings once again will be in the west where the mercury should
top out in the lower 50s, while roughly along and east of the I-55
corridor, afternoon highs will be mostly in the 40s, with a few
locations over east central IL just getting to 40 degree later
this afternoon.
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 505 AM CST SAT DEC 5 2015
IFR TO VLIFR conditions are expected thru the morning hours before
a gradual improvement this afternoon, especially across our
western TAF sites. We have seen a temporary improvement in cigs
and vsbys at BMI and SPI but based on satellite and surface obs
to our east and south, it looks as if the cigs and vsbys will
come down again at both sites in the next hour or two. Forecast
soundings not offering much hope for any significant break in the
cigs late this morning into this afternoon with PIA and SPI seeing
the best chance for cigs to break for a time. Little change in the
air mass is expected as we head into the overnight hours with
the threat for fog and low cigs to redevelop again and hold into
the morning hours of Sunday. Surface winds will remain a non-
factor thru tonight with a south to southeast wind at 7 to
12 kts today, and from 5 to 10 kts tonight.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ027>031-036>038-
041>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
315 AM CST SAT DEC 5 2015
.SHORT TERM...
312 AM CST
THROUGH SUNDAY NIGHT...
LOW STRATUS AND FOG THE PRIMARY FORECAST CONCERNS OVER THE NEXT
COUPLE DAYS. SURFACE HIGH PRESSURE IS CENTERED OVER THE UPPER OHIO
VALLEY EARLY THIS MORNING AND IS PROGGED TO BUILD TOWARDS THE
MID ATLANTIC COAST OVER THE WEEKEND. SATELLITE IMAGERY AND SURFACE
OBS SHOWS LOW STRATUS AND FOG BLANKETING THE EASTERN 2/3 OR SO OF
ILLINOIS AND PRACTICALLY ALL OF INDIANA. CLOUDS HAVE BEEN STEADILY
SPREADING NORTHWEST OVERNIGHT AND SHOULD BLANKET THE ENTIRE
FORECAST AREA THROUGH THE MORNING. THEREAFTER...THE ONLY MODEL
THAT WANTS TO HOLD ONTO THE CLOUD COVER THROUGH THE MAJORITY OF
THE DAY IS THE HRRR WHICH SEEMS FAIRLY REASONABLE GIVEN LACK OF
EROSION YESTERDAY. MOST OTHER MODELS BEGIN TO ERODE THE STRATUS BY
MIDDAY HOWEVER A RATHER IMPRESSIVE LOW LEVEL INVERSION COULD KEEP
THE LOW LEVEL MOISTURE TRAPPED THROUGH MUCH OF THE WEEKEND. 05Z
AMDAR SOUNDING OUT OF THE CHICAGO AREA SHOWED 980MB TEMP OF 0.3C
SHARPLY WARMING TO 9.0C AROUND 935MB. LATEST FORECAST GOES UNDER
THE ASSUMPTION THAT MOST OF THE CWA WILL REMAIN UNDER OVERCAST
SKIES AND HAVE ADJUSTED TEMPS DOWN QUITE A BIT FROM PREVIOUS
FORECASTS. FAR NORTH CENTRAL ILLINOIS WILL HAVE THE BEST CHANCE TO
SEE SOME EROSION ALONG THE EDGE OF THE STRATUS DECK BUT CONFIDENCE
IS LOW HOW THIS WILL PLAY OUT OR WHERE TO DRAW THE LINE. AS IS
TYPICAL WITH THESE SCENARIOS THERE IS LARGE BUST POTENTIAL...WITH
HIGHS ONLY IN THE UPPER 30S TO AROUND 40 ON THE COLD END UNDER
CLOUDS ALL DAY BUT IF SUNSHINE IS ABLE TO BREAK THROUGH...THOSE
VERY WARM TEMPS ALOFT WOULD SUPPORT TEMPERATURES QUICKLY SHOOTING
UP WITH HIGHS IN THE LOW 50S. OVERNIGHT...BOUNDARY LAYER FLOW
BACKS SLIGHTLY SO WOULD ANTICIPATE ANY LOW CIGS TO SPREAD BACK TO
ANY AREAS IN NORTH CENTRAL ILLINOIS THAT MIGHT ERODE ALONG THE
EDGE OF THE STRATUS...BUT CONFIDENCE IS FAIRLY LOW HOW THIS WILL
PLAY OUT.
SATURDAY NIGHT INTO SUNDAY...AN UPPER LEVEL WAVE WILL TRANSLATE
EAST ACROSS THE PLAINS REACHING THE OHIO VALLEY BY SUNDAY
EVENING. MID LEVEL HEIGHT FALLS IN ADVANCE OF THIS SYSTEM BEGIN TO
OVERSPREAD NORTHERN ILLINOIS SATURDAY NIGHT THOUGH THE BULK OF THE
FORCING STAYS SOUTH OF THE CWA DURING THE DAY SUNDAY. OUTSIDE OF
THE POSSIBLE CONTINUING LOW STRATUS...FAIRLY LITTLE MOISTURE IS
EXPECTED WITH THIS SYSTEM. MIGHT BE ABLE TO SQUEEZE OUT SOME
DRIZZLE SATURDAY NIGHT INTO EARLY SUNDAY BUT OTHERWISE CONFINED
POPS TO SOUTHWEST AREAS OF THE CWA AND ONLY SLIGHT CHC. LOW LEVEL
CLOUDS IF STILL AROUND EXPECTED TO FINALLY ERODE SUNDAY...HOWEVER
MID AND HIGH CLOUD COVER WILL BE INCREASING ACROSS THE AREA.
DEUBELBEISS
&&
.LONG TERM...
312 AM CST
MONDAY THROUGH FRIDAY...
UPPER PATTERN WILL BECOME ZONAL FOR THE UPCOMING WEEK WITH A
SERIES OF DISTURBANCES BRINGING PERIODIC CHANCES FOR PRECIP
PARTICULARLY THE LATTER HALF OF THE WEEK. TEMPERATURES SHOULD
REMAIN MILD THROUGH THE ENTIRE WEEK WITH A GRADUAL WARMING TREND
EXPECTED. TEMPERATURES ON MONDAY WILL MAX IN THE MID 40S ACROSS
THE FORECAST AREA AND LOW 50S ARE POSSIBLE BY THURSDAY AND FRIDAY.
BOTH THE ECMWF AND GFS ADVERTISE A SHORTWAVE TROUGH DROPPING
ACROSS UPPER MIDWEST/WESTERN GREAT LAKES WEDNESDAY NIGHT.
THEN...WILL HAVE TO KEEP A CLOSE EYE ON A POTENTIALLY MORE POTENT
SYSTEM LATE IN THE WEEK...THOUGH MODELS CONTINUE TO BOUNCE AROUND
ON THE DETAILS AS THEY STRUGGLE TO HANDLE THE PHASING OF UPPER
LEVEL ENERGY.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* LIFR CIGS AND IFR/LIFR VSBY WILL PERSIST THROUGH AT LEAST MID
MORNING...POSSIBLY THROUGH MIDDAY.
* STRATUS/FOG MAY CLEAR OUT LATER THIS AFTERNOON.
RATZER
//DISCUSSION...UPDATED 09Z...
AFTER INITIAL DROP AS LOW AS 1/2SM AND OVC002 AT MDW EARLIER...
CONDITIONS HAVE IMPROVED SLIGHTLY. WOULD EXPECT SOME SLOW
DETERIORATION THROUGH REMAINDER OF THE PRE-DAWN HOURS...THOUGH DO
NOT HAVE MUCH CONFIDENCE IN JUST HOW LOW. WORST CONDITIONS...VLIFR
IN SPOTS...HAVE GENERALLY HELD WEST AND SOUTHEAST OF THE CHICAGO
METRO TERMINALS WITH STRATUS/FOG HAVING ALSO SPREAD NORTHWEST INTO
RFD. HAVE ADJUSTED ORD/MDW AND GYY TO BE JUST A BIT MORE
OPTIMISTIC BASED ON TRENDS OF LAST SEVERAL HOURS.
RATZER
PREVIOUS DISCUSSION FROM 06Z...
LARGE AREA OF LOW STRATUS/FOG HAS EXPANDED NORTH-NORTHWESTWARD
ACROSS CHICAGO TERMINALS AS OF 0530Z...AND IS EXPECTED TO CONTINUE
TO SPREAD NORTHWEST INTO ROCKFORD WITHIN THE NEXT COUPLE HOURS.
COMBINATION OF PERSISTENT LIGHT MOIST SOUTH FLOW IN LOW AND A
STRONG INVERSION BASED AROUND 850 FT AGL PER RECENT AMDAR ASCENT
SOUNDINGS FROM ORD IS EXPECTED TO MAINTAIN POOR CONDITIONS THROUGH
MORNING. NOT MUCH NOTED TO HELP ERODE STRATUS SATURDAY MORNING...
WITH DECEMBER CLIMATOLOGY BACKED BY LOW SUN ANGLE AND SHORT
DAYLIGHT HOURS EXPECTED TO ALLOW ONLY SLOW EROSION PRIMARILY FROM
THE EDGES DURING THE DAY. TIMING OF IMPROVEMENT REMAINS A LOW
CONFIDENCE FORECAST...AND HAVE MADE NO BIG CHANGES FROM PREVIOUS
FORECAST THINKING. SOME GUIDANCE SUGGESTS REDEVELOPMENT AGAIN
SATURDAY EVENING...THOUGH INCREASE IN HIGH CLOUD COVER MAY HELP
PREVENT FROM COOLING/SATURATING SOMEWHAT.
WINDS THROUGH THE FORECAST PERIOD SHOULD REMAIN SOUTH...170 TO 200
DEG 10 KTS OR LESS.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH IN FOG AND STRATUS WITH LIFR CIGS AND IFR/LIFR VSBY
THROUGH AT LEAST MID MORNING SATURDAY.
* LOW IN EXACTLY HOW LOW VSBY DROPS...BUT HIGH IN FALLING TO AT LEAST
1SM.
* LOW IN TIMING IMPROVEMENT TO VFR LATER TODAY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY THROUGH THURSDAY...PRIMARILY VFR. SMALL DAY TO DAY CHANCE
OF IFR CIGS/FOG DURING LATE NIGHTS/MORNINGS.
IZZI
&&
.MARINE...
250 AM CST
HIGH PRESSURE MOVING EAST ACROSS THE UPPER OHIO VALLEY TO THE MID
ATLANTIC REGION TODAY...AND LOW PRESSURE MOVING FROM MANITOBA TO
HUDSON BAY...WILL ALLOW SOUTH-SOUTHWEST WINDS TO PERSIST ACROSS
LAKE MICHIGAN. THE GRADIENT WILL TIGHTEN DURING THE DAY IN
RESPONSE TO PRESSURE FALLS ASSOCIATED WITH THE CANADIAN LOW...
WITH SOUTHERLY WINDS INCREASING INTO THE 30 KT RANGE THIS
AFTERNOON INTO TONIGHT OVER THE NORTHERN PART OF THE LAKE. THE
GRADIENT WILL THEN WEAKEN SUNDAY AS A WEAK COLD FRONT SLIDES
SOUTHEAST ACROSS THE LAKE...WITH WINDS SHIFTING TO THE WEST-
NORTHWEST. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
SUNDAY NIGHT INTO MONDAY...BEFORE THE PATTERN REVERTS TO LOW
PRESSURE LIFTING NORTHEAST ACROSS CANADA AND NORTH OF THE LAKES
AND BRINGS A RETURN TO SOUTH-SOUTHWEST WINDS INTO EARLY NEXT WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039 UNTIL NOON SATURDAY.
IN...DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL
NOON SATURDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
244 AM CST SAT DEC 5 2015
.SHORT TERM...(Today)
ISSUED AT 243 AM CST SAT DEC 5 2015
Dense fog continues to expand north and west early this morning as
the boundary layer flow remains out of the east and southeast. Have
expanded the Dense Fog advisory to include all counties except
Schuyler until Noon. Latest few runs of the HRRR suggest the fog
will edge west to Schuyler county just after 12z and then begin to
dissipate after sunrise. High pressure centered over Ohio will inch
slowly away from the area with the ridge axis forecast to extend
west into our area through much of the day. Forecast soundings
showing a very shallow moist layer at the surface trapped underneath
a strong low level inversion thru the day with our west and
southwest counties seeing the sun first with our eastern counties
not seeing any significant breaks until this afternoon, if then.
For what is usually a recipe for a big temperature bust, will use
continuity with respect to forecast highs this afternoon with a
very similar setup to what we experienced yesterday. Based off
that reasoning, will go fairly close to the highs obtained
yesterday afternoon, especially across the east where readings in
some areas didn`t get out of the 30s. Don`t have anything quite
that cool today as RUC soundings even in our far east were showing
several hours where we could see a little sunshine, unlike the
latest HRRR run which was showing the stratus and low visibilitiesholding
across our east throughout the afternoon. Our warmest readings
once again will be in the west where the mercury should top out in
the lower 50s, while roughly along and east of the I-55 corridor,
afternoon highs will be mostly in the 40s, with a few locations
over east central IL just getting to 40 degree later this
afternoon.
&&
.LONG TERM...(Tonight through Friday)
ISSUED AT 243 AM CST SAT DEC 5 2015
Low level inversion does not appear to be going away until Sunday,
when a shortwave currently located over Idaho and Utah arrives. SREF
probability guidance indicates the fog is likely to expand westward
once again this evening and cover most areas north of I-70. Would
not be surprised if another fog advisory is needed, but will wait to
see how much conditions can improve this afternoon first.
Aforementioned upper wave will close off as it crosses Illinois
Sunday afternoon. Have increased PoP`s to about 30% west of a Peoria
to Springfield line, mostly on the back side of the low, and
introduced 30% PoP`s across the southeast quarter of the forecast
area for evening as the low shifts into Indiana.
Remainder of the forecast period will be fairly mild for this time
of year, as the general upper flow remains of Pacific origin. Some
questions exist for late week, as one upper wave in particular digs
as it crosses the Dakotas. The ECMWF is more aggressive with this
digging and draws some colder air aloft southward from Manitoba,
producing a slower and more robust surface low/front Thursday night.
The GFS is much weaker and basically has a dry frontal passage.
Leaned a bit more toward the slower solution for now, but did not
make any significant changes to the initialized forecast grids due
to the uncertainty.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1143 PM CST FRI DEC 4 2015
Will continue the dense fog for CMI/DEC/BMI/SPI and think the
dense fog will finally get into PIA around 08z based on satellite
trends showing edge of low clouds/fog pushing slowly north and
west toward the area. The dense fog will continue at all sites
overnight and likely into the morning hours as well. PIA and SPI
will improve first, being on the western edge of the LIFR/VLIFR
conditions. DEC/BMI/CMI will improve later, maybe early afternoon
as some eroding and mixing occurs. However, thinking the cigs
below 500 ft will continue at those sites during the afternoon but
vis will improve to around 2-3sm. Unfortunately, believe a return
to LIFR conditions will occur again tomorrow evening so have
continued low cigs and reduced vis to below 1sm at BMI/CMI, around
1sm for DEC, around 2sm for SPI and 3sm for PIA. These conditions
will occur early afternoon in the east and then later in the west.
Winds will be southeast through the period.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until noon CST today for ILZ027>031-036>038-
041>057-061>063-066>068-071>073.
&&
$$
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
928 PM EST SUN DEC 6 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 211 PM EST SUN DEC 6 2015
A SERIES OF UPPER WAVES WILL BRING SMALL RAIN CHANCES TO CENTRAL
INDIANA TONIGHT AND AGAIN WEDNESDAY. THEN...A DEEP UPPER TROUGH WILL
SET UP OVER THE SOUTHWESTERN STATES. DISTURBANCES WILL EJECT
NORTHEASTWARD AROUND THE BASE OF THE UPPER TROUGH AND THROUGH THE
OHIO VALLEY. ALSO...A FRONTAL SYSTEM WILL APPROACH FROM THE WEST.
THESE FEATURES WILL INTERACT WITH INCREASING AMOUNTS OF MOISTURE TO
BRING PROLONGED RAIN CHANCES TO ALL OF CENTRAL INDIANA LATE NEXT
WEEK AND NEXT WEEKEND.
TEMPERATURES WILL START OFF SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE
MID TO UPPER 40S MONDAY. IT WILL BECOME EVEN MORE MILD LATER IN THE
WEEK AND NEXT WEEKEND WITH AFTERNOON HIGHS IN THE LOWER 60S POSSIBLE
BY SATURDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 746 PM EST SUN DEC 6 2015
0030Z UPDATE...MAIN UPDATE EARLY THIS EVENING WAS TO INCREASE THE
COVERAGE FOR LIGHT RAIN SHOWERS EARLY THIS EVENING BASED ON LATEST
RADAR MOSAIC AND HRRR SOLUTION. THIS INCREASES THE POPS ACROSS
SOME OF THE NORTHERN COUNTIES THROUGH THIS EVENING BEFORE THE
BETTER LIFT AND MOISTURE MOVES SOUTH OF THE AREA. OTHER MINOR
UPDATES WERE MADE TO ACCOUNT FOR THE LATEST IN TEMP/DEW POINT/WIND
DIR/SPEED TRENDS. ZFPIND AND ASSOCIATED FORECAST PRODUCTS ALREADY.
PREVIOUS DISCUSSION FOLLOWS.
POPS WILL BE THE MAIN FOCUS TONIGHT AS AN UPPER LOW MOVES THROUGH
THE ZONAL FLOW ALOFT AND TRACKS ACROSS THE INDIANA-MICHIGAN BORDER.
WATER VAPOR LOOP WAS SHOWING THE UPPER LOW SPINNING ACROSS
SOUTHEASTERN IOWA THIS AFTERNOON. THE MODELS ARE CLOSE AND BRING THE
CENTER OF THE LOW TO NORTHEASTERN ILLINOIS BY 00Z TONIGHT AND TO
WESTERN PARTS OF LAKE ERIE 12Z MONDAY. THE 12Z GFS...NAM AND GEM HAD
ALL THE QPF NEAR AND SOUTH OF INTERSTATE 70...WHEREAS THE 00Z ECMWF
HAD IT FURTHER NORTH ACROSS MUCH OR ALL OF CENTRAL INDIANA. THIS
SEEMS TO GO ALONG THE FORMER MODELS BEING MORE COMPACT AND FURTHER
SOUTH WITH THE HIGHER 1000-500 MILLIBAR RH BULLSEYE. WILL GO WITH
THE MAJORITY AND KEEP CHANCE POPS SOUTH AND TRANSITION TO DRY ACROSS
THE NORTHERNMOST TIER OR TWO. THE RAIN SHOWERS SHOULD BE ENDING FROM
WEST TO EAST OVERNIGHT.
WITH LOW STRATOCU DECK AROUND...PREFER THE WARMER 12Z GFS AND
ENSEMBLE MOS. THE WET BULB ZERO TEMPERATURE SHOULD STAY JUST ABOVE
FREEZING...SO DO NOT THINK WE WILL SEE A MIX OR CHANGEOVER OF THE
RAIN SHOWERS TO SNOW SHOWERS. ALSO...SOME UPSTREAM LOW VISIBILITIES
WERE SEEN IN THE SURFACE OBS ACROSS MISSOURI AND IOWA EARLY THIS
AFTERNOON...SO WILL INCLUDE PATCHY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 211 PM EST SUN DEC 6 2015
MAIN CHALLENGE TO THE SHORT TERM WILL BE POPS AND CLOUD COVER AS
MODELS HAVE A PAIR OF UPPER WAVES MOVING THROUGH THE VICINITY
THROUGH WEDNESDAY. MODELS ARE HAVING DIFFERENCES WITH TIMING AND
LOCATION WITH THESE FEATURES...WHICH MANY TIMES IS THE CASE IN
DISTURBANCES MOVING THROUGH FAST ZONAL FLOW.
THE WORK WEEK SHOULD START OFF WITH LINGERING STRATUS AND PATCHY FOG
AS THE UPPER LOW MOVES TO WESTERN PARTS OF LAKE ERIE. MODEL
SOUNDINGS SUGGEST STRONG INVERSION SHOULD KEEP AT LEAST SOME
STRATOCU AROUND...AND LOCAL TRAPPING FLOW CHART SUGGESTS CLOUDS WILL
HANG AROUND UP TO 24 HOURS LONGER THAN MOS SUGGESTS. SO...WILL SHOOT
FOR MOSTLY CLOUDY TOMORROW. THIS SHOULD ALSO KEEP TEMPERATURES FROM
HITTING 50 DEGREES DESPITE NICE LOW LEVEL THERMAL SETUP.
THE 12Z GFS...CANADIAN AND NAM ARE THEN MUCH STRONGER AND FASTER AND
FURTHER NORTH BRINGING AN UPPER WAVE OVER THE GREAT LAKES MONDAY
NIGHT. THE 00Z ECMWF DOES NOT BRING THE WAVE ACROSS UNTIL TUESDAY
AND BRINGS IT ACROSS THE OHIO VALLEY. EITHER WAY...MOISTURE IS
LACKING SO...WILL NOT HAVE POPS MONDAY NIGHT OR TUESDAY.
BY TUESDAY...THE LOWER LEVELS DRY ENOUGH THAT THERE SHOULD BE SOME
SUNSHINE AROUND AFTER MORE MORNING STRATUS. LOW LEVEL THERMAL PROGS
AND SOME SUNSHINE SUGGEST TEMPERATURES SHOULD BE A FEW DEGREES
WARMER ON TUESDAY WITH MOS BLEND OF UPPER 40S TO LOWER 50S.
THE LAST WAVE OF CONCERN SHOULD MOVE THROUGH THE OHIO VALLEY AND
GREAT LAKES ON WEDNESDAY. THE 12Z NAM LOOKS TO BE THE ODD ONE OUT
BEING MUCH FURTHER NORTH. WITH INCREASING SOUTHWESTERLY FLOW OVER
THE AREA ON THE BACK SIDE OF AN EAST COAST HIGH...WILL SEE
INCREASING MOISTURE TO GO ALONG WITH DECENT FORCING. THUS...AT LEAST
CHANCE POPS FOR RAIN SHOWERS LOOK GOOD ACROSS ALL OF CENTRAL INDIANA
ON WEDNESDAY.
THE CLOUDS WILL KEEP TEMPERATURES FROM FALLING MUCH TUESDAY NIGHT
WITH LOWS IN THE UPPER 30S TO LOWER 40S. THE CLOUDS AND SHOWERS
SHOULD ALSO KEEP TEMPERATURES FROM RISING TOO MUCH WEDNESDAY WITH
HIGHS IN THE UPPER 40S AND LOWER 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 247 PM EST SUN DEC 6 2015
A QUASI-ZONAL FLOW ALOFT WILL OCCUR DURING THE FIRST HALF OF THE
LONG TERM PERIOD AND THEN BECOME MORE AMPLIFIED OVER THE WEEKEND
AS A STRONG UPPER TROUGH DIGS INTO THE CENTRAL U.S. BY LATE
SATURDAY AND THEN MOVES TO THE WESTERN GREAT LAKES AND MISSISSIPPI
VALLEY BY THE END OF DAY 7. A WEAK UPPER DISTURBANCE WILL BRING
A CHANCE OF SHOWERS AROUND THURSDAY NIGHT AND THEN THE STRONG UPPER
TROUGH WILL BRING A GOOD CHANCE OF SHOWERS OVER THE WEEKEND...
ESPECIALLY SUNDAY. THERE MAY BE ENOUGH FORCING FOR ISOLATED THUNDER
SATURDAY NIGHT INTO SUNDAY...BUT AT THE MOMENT I DECIDED TO LEAVE IT OUT.
OVERALL SUPER BLEND SEEMED TO HANDLE POPS WELL. RAISED LOW TEMPERATURES
SLIGHTLY SOME PERIODS DUE TO CLOUDS AND STRONG WARM ADVECTION.
OTHERWISE...ONLY MINOR TWEAKS MADE DURING THE REST OF THE PERIOD. MODELS
INDICATE TEMPERATURES WILL BE WELL ABOVE NORMAL DURING THE PERIOD...BUT
POSSIBLY TURNING COOLER LATE SUNDAY WITH THE COLD FRONT.
&&
.AVIATION /DISCUSSION FOR THE 07/03Z TAF UPDATE/...
ISSUED AT 928 PM EST SUN DEC 6 2015
MINOR ADJUSTMENT TO IND PER OBS TRENDS. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 623 PM EST SUN DEC 6 2015
VFR INITIALLY WILL GIVE WAY TO MVFR OR WORSE RESTRICTIONS LATER
TONIGHT INTO MONDAY. LOW CONFIDENCE FORECAST HOWEVER AS VARIOUS
GUIDANCE PRODUCTS DIFFER SIGNIFICANTLY IN THEIR HANDLING OF EXPECTED
CONDITIONS.
UPSTREAM CEILINGS AND VISIBILITIES ARE INITIALLY VFR WITH COMPACT
AREA OF SHOWERS ASSOCIATED WITH UPPER LOW. WAKE OF THE SYSTEM AN
EXPANSIVE AREA OF LOW CEILINGS AND SOME REDUCED VISIBILITIES NOTED.
WILL GENERALLY TREND THINGS DOWN TO LOW END MVFR BY THE EARLY PART
OF THE OVERNIGHT AND KEEP THEM THERE THROUGH EARLY AFTERNOON MONDAY
AS GUIDANCE TYPICALLY CLEARS SKIES FAR TOO EARLY IN THESE SITUATIONS.
WINDS WILL BE 5KT OR LESS THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...SMF/MK
SHORT TERM...MK
LONG TERM...JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
801 PM EST SUN DEC 6 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 211 PM EST SUN DEC 6 2015
A SERIES OF UPPER WAVES WILL BRING SMALL RAIN CHANCES TO CENTRAL
INDIANA TONIGHT AND AGAIN WEDNESDAY. THEN...A DEEP UPPER TROUGH WILL
SET UP OVER THE SOUTHWESTERN STATES. DISTURBANCES WILL EJECT
NORTHEASTWARD AROUND THE BASE OF THE UPPER TROUGH AND THROUGH THE
OHIO VALLEY. ALSO...A FRONTAL SYSTEM WILL APPROACH FROM THE WEST.
THESE FEATURES WILL INTERACT WITH INCREASING AMOUNTS OF MOISTURE TO
BRING PROLONGED RAIN CHANCES TO ALL OF CENTRAL INDIANA LATE NEXT
WEEK AND NEXT WEEKEND.
TEMPERATURES WILL START OFF SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE
MID TO UPPER 40S MONDAY. IT WILL BECOME EVEN MORE MILD LATER IN THE
WEEK AND NEXT WEEKEND WITH AFTERNOON HIGHS IN THE LOWER 60S POSSIBLE
BY SATURDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 746 PM EST SUN DEC 6 2015
0030Z UPDATE...MAIN UPDATE EARLY THIS EVENING WAS TO INCREASE THE
COVERAGE FOR LIGHT RAIN SHOWERS EARLY THIS EVENING BASED ON LATEST
RADAR MOSAIC AND HRRR SOLUTION. THIS INCREASES THE POPS ACROSS
SOME OF THE NORTHERN COUNTIES THROUGH THIS EVENING BEFORE THE
BETTER LIFT AND MOISTURE MOVES SOUTH OF THE AREA. OTHER MINOR
UPDATES WERE MADE TO ACCOUNT FOR THE LATEST IN TEMP/DEW POINT/WIND
DIR/SPEED TRENDS. ZFPIND AND ASSOCIATED FORECAST PRODUCTS ALREADY.
PREVIOUS DISCUSSION FOLLOWS.
POPS WILL BE THE MAIN FOCUS TONIGHT AS AN UPPER LOW MOVES THROUGH
THE ZONAL FLOW ALOFT AND TRACKS ACROSS THE INDIANA-MICHIGAN BORDER.
WATER VAPOR LOOP WAS SHOWING THE UPPER LOW SPINNING ACROSS
SOUTHEASTERN IOWA THIS AFTERNOON. THE MODELS ARE CLOSE AND BRING THE
CENTER OF THE LOW TO NORTHEASTERN ILLINOIS BY 00Z TONIGHT AND TO
WESTERN PARTS OF LAKE ERIE 12Z MONDAY. THE 12Z GFS...NAM AND GEM HAD
ALL THE QPF NEAR AND SOUTH OF INTERSTATE 70...WHEREAS THE 00Z ECMWF
HAD IT FURTHER NORTH ACROSS MUCH OR ALL OF CENTRAL INDIANA. THIS
SEEMS TO GO ALONG THE FORMER MODELS BEING MORE COMPACT AND FURTHER
SOUTH WITH THE HIGHER 1000-500 MILLIBAR RH BULLSEYE. WILL GO WITH
THE MAJORITY AND KEEP CHANCE POPS SOUTH AND TRANSITION TO DRY ACROSS
THE NORTHERNMOST TIER OR TWO. THE RAIN SHOWERS SHOULD BE ENDING FROM
WEST TO EAST OVERNIGHT.
WITH LOW STRATOCU DECK AROUND...PREFER THE WARMER 12Z GFS AND
ENSEMBLE MOS. THE WET BULB ZERO TEMPERATURE SHOULD STAY JUST ABOVE
FREEZING...SO DO NOT THINK WE WILL SEE A MIX OR CHANGEOVER OF THE
RAIN SHOWERS TO SNOW SHOWERS. ALSO...SOME UPSTREAM LOW VISIBILITIES
WERE SEEN IN THE SURFACE OBS ACROSS MISSOURI AND IOWA EARLY THIS
AFTERNOON...SO WILL INCLUDE PATCHY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 211 PM EST SUN DEC 6 2015
MAIN CHALLENGE TO THE SHORT TERM WILL BE POPS AND CLOUD COVER AS
MODELS HAVE A PAIR OF UPPER WAVES MOVING THROUGH THE VICINITY
THROUGH WEDNESDAY. MODELS ARE HAVING DIFFERENCES WITH TIMING AND
LOCATION WITH THESE FEATURES...WHICH MANY TIMES IS THE CASE IN
DISTURBANCES MOVING THROUGH FAST ZONAL FLOW.
THE WORK WEEK SHOULD START OFF WITH LINGERING STRATUS AND PATCHY FOG
AS THE UPPER LOW MOVES TO WESTERN PARTS OF LAKE ERIE. MODEL
SOUNDINGS SUGGEST STRONG INVERSION SHOULD KEEP AT LEAST SOME
STRATOCU AROUND...AND LOCAL TRAPPING FLOW CHART SUGGESTS CLOUDS WILL
HANG AROUND UP TO 24 HOURS LONGER THAN MOS SUGGESTS. SO...WILL SHOOT
FOR MOSTLY CLOUDY TOMORROW. THIS SHOULD ALSO KEEP TEMPERATURES FROM
HITTING 50 DEGREES DESPITE NICE LOW LEVEL THERMAL SETUP.
THE 12Z GFS...CANADIAN AND NAM ARE THEN MUCH STRONGER AND FASTER AND
FURTHER NORTH BRINGING AN UPPER WAVE OVER THE GREAT LAKES MONDAY
NIGHT. THE 00Z ECMWF DOES NOT BRING THE WAVE ACROSS UNTIL TUESDAY
AND BRINGS IT ACROSS THE OHIO VALLEY. EITHER WAY...MOISTURE IS
LACKING SO...WILL NOT HAVE POPS MONDAY NIGHT OR TUESDAY.
BY TUESDAY...THE LOWER LEVELS DRY ENOUGH THAT THERE SHOULD BE SOME
SUNSHINE AROUND AFTER MORE MORNING STRATUS. LOW LEVEL THERMAL PROGS
AND SOME SUNSHINE SUGGEST TEMPERATURES SHOULD BE A FEW DEGREES
WARMER ON TUESDAY WITH MOS BLEND OF UPPER 40S TO LOWER 50S.
THE LAST WAVE OF CONCERN SHOULD MOVE THROUGH THE OHIO VALLEY AND
GREAT LAKES ON WEDNESDAY. THE 12Z NAM LOOKS TO BE THE ODD ONE OUT
BEING MUCH FURTHER NORTH. WITH INCREASING SOUTHWESTERLY FLOW OVER
THE AREA ON THE BACK SIDE OF AN EAST COAST HIGH...WILL SEE
INCREASING MOISTURE TO GO ALONG WITH DECENT FORCING. THUS...AT LEAST
CHANCE POPS FOR RAIN SHOWERS LOOK GOOD ACROSS ALL OF CENTRAL INDIANA
ON WEDNESDAY.
THE CLOUDS WILL KEEP TEMPERATURES FROM FALLING MUCH TUESDAY NIGHT
WITH LOWS IN THE UPPER 30S TO LOWER 40S. THE CLOUDS AND SHOWERS
SHOULD ALSO KEEP TEMPERATURES FROM RISING TOO MUCH WEDNESDAY WITH
HIGHS IN THE UPPER 40S AND LOWER 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 247 PM EST SUN DEC 6 2015
A QUASI-ZONAL FLOW ALOFT WILL OCCUR DURING THE FIRST HALF OF THE
LONG TERM PERIOD AND THEN BECOME MORE AMPLIFIED OVER THE WEEKEND
AS A STRONG UPPER TROUGH DIGS INTO THE CENTRAL U.S. BY LATE
SATURDAY AND THEN MOVES TO THE WESTERN GREAT LAKES AND MISSISSIPPI
VALLEY BY THE END OF DAY 7. A WEAK UPPER DISTURBANCE WILL BRING
A CHANCE OF SHOWERS AROUND THURSDAY NIGHT AND THEN THE STRONG UPPER
TROUGH WILL BRING A GOOD CHANCE OF SHOWERS OVER THE WEEKEND...
ESPECIALLY SUNDAY. THERE MAY BE ENOUGH FORCING FOR ISOLATED THUNDER
SATURDAY NIGHT INTO SUNDAY...BUT AT THE MOMENT I DECIDED TO LEAVE IT OUT.
OVERALL SUPER BLEND SEEMED TO HANDLE POPS WELL. RAISED LOW TEMPERATURES
SLIGHTLY SOME PERIODS DUE TO CLOUDS AND STRONG WARM ADVECTION.
OTHERWISE...ONLY MINOR TWEAKS MADE DURING THE REST OF THE PERIOD. MODELS
INDICATE TEMPERATURES WILL BE WELL ABOVE NORMAL DURING THE PERIOD...BUT
POSSIBLY TURNING COOLER LATE SUNDAY WITH THE COLD FRONT.
&&
.AVIATION /DISCUSSION FOR THE 07/00Z TAFS/...
ISSUED AT 623 PM EST SUN DEC 6 2015
VFR INITIALLY WILL GIVE WAY TO MVFR OR WORSE RESTRICTIONS LATER
TONIGHT INTO MONDAY. LOW CONFIDENCE FORECAST HOWEVER AS VARIOUS
GUIDANCE PRODUCTS DIFFER SIGNIFICANTLY IN THEIR HANDLING OF EXPECTED
CONDITIONS.
UPSTREAM CEILINGS AND VISIBILITIES ARE INITIALLY VFR WITH COMPACT
AREA OF SHOWERS ASSOCIATED WITH UPPER LOW. WAKE OF THE SYSTEM AN
EXPANSIVE AREA OF LOW CEILINGS AND SOME REDUCED VISIBILITIES NOTED.
WILL GENERALLY TREND THINGS DOWN TO LOW END MVFR BY THE EARLY PART
OF THE OVERNIGHT AND KEEP THEM THERE THROUGH EARLY AFTERNOON MONDAY
AS GUIDANCE TYPICALLY CLEARS SKIES FAR TOO EARLY IN THESE SITUATIONS.
WINDS WILL BE 5KT OR LESS THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...SMF/MK
SHORT TERM...MK
LONG TERM...JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
103 AM EST SAT DEC 5 2015
.SYNOPSIS...
ISSUED AT 100 AM EST SAT DEC 5 2015
AREAS OF DENSE FREEZING FOG WILL PERSIST OVERNIGHT AND BE SLOW TO
LIFT THIS MORNING. TEMPERATURES EARLY THIS MORNING SHOULD DROP TO
NEAR 30 DEGREES. SOME TEMPORARY CLEARING IS EXPECTED BY LATE TODAY
WITH HIGHS IN THE 40S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
FAIRLY DRASTIC OVERALL TO GRIDS FOR TONIGHT INTO SATURDAY MORNING
TO REFLECT INCREASING CONCERNS FOR RAPID REDEVELOPMENT OF WIDESPREAD
STRATUS AND FOG (POSSIBLY DENSE) ACROSS THE AREA. VIS SAT AND
OBSERVATIONS SHOW SCOURING OUT OF STRATUS DECK CONTINUES...BUT WILL
LIKELY REACH THE END OF THIS OCCURRING IN THE NEXT HOUR OR 2 AS PEAK
HEATING AND MIXING DIMINISHES. DESPITE THE CLEARING A SLOW INCREASE
IN LOW LEVEL MSTR COMBINED WITH LIGHT WINDS AND MOSTLY CLEAR TO
CLEAR SKIES WILL SET THE STAGE FOR RAPID DEVELOPMENT OF STRATUS
ACROSS THE AREA THIS EVENING. HRRR HAS BEEN HANDLING OVERALL SETUP
QUITE WELL BOTH LAST NIGHT AND TODAY AND QUICKLY BRINGS STRATUS AND
DENSE FOG BACK IN BETWEEN 3 AND 6Z SAT. GRIDS NOW REFLECT A RETURN
TO CLOUDY SKIES BY LATE EVENING WITH PATCHY FOG
INITIALLY...EVENTUALLY GOING TO AREAS OF FOG. WHERE FULL CLEARING
HAS TAKEN PLACE...A MENTION OF PATCHY DENSE FREEZING FOG HAS BEEN
ADDED AS TEMPS DROP BELOW FREEZING ACROSS THE AREA AND GREATER
CONCENTRATION OF WATER DROPLETS MAY GIVE A LIGHT GLAZE ON ELEVATED
SURFACES. FOR NOW WILL HOLD OFF ON ANY HEADLINES AND DEFER TO EVE
SHIFT TO MONITOR TRENDS AS COULD END UP MAINLY THE STRATUS ISSUE AND
VSBYS BEHAVE THEMSELVES.
NEXT CHALLENGE WILL BE IF THE STRATUS/FOG CAN LIFT DURING THE DAY
SATURDAY AS INVERSION REMAINS IN PLACE. CLEARING MAY BE HIGHLY
DEPENDENT ON ACTUAL DEPTH OF THE STRATUS DECK. TODAY IT WAS ON
THE THINNER SIDE AND ALLOWED AT LEAST SOME MIXING. THIS MAY NOT BE
THE CASE TOMORROW AS RIDGE AXIS SHIFTS OVERHEAD AND POTENTIALLY
TRAPS THE LOW CLOUDS AND SOME FOG THROUGH THE DAY. FOR NOW WILL
KEEP WITH AT LEAST SOME CLEARING...BUT EXTENSIVE UPDATE CHANGES
MAY BE NEEDED IN LATER FORECASTS. WILL GO WITH GENERAL PERSISTENCE
ON TEMPS AS WELL WITH BUST POTENTIAL MODERATE TO HIGH.
&&
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 300 PM EST FRI DEC 4 2015
LONG TERM PERIOD BEGINS QUIETLY...WITH LARGE SCALE RIDGE AXIS
CENTERED EAST OF THE REGION SUNDAY AND UPPER TROF/CUTOFF LOW
APPROACHING THE REGION FROM THE WEST. CONTINUED WITH A DRY FORECAST
OF 14 POPS OR LESS SUNDAY NIGHT/EARLY MONDAY AS THIS SYSTEM PASSES
THROUGH THE REGION...WITH A BULK OF THE FORCING AND MOISTURE
REMAINING SOUTH OF THE REGION.
A ZONAL FLOW REGIME TAKES HOLD ACROSS THE CONUS THROUGH MUCH OF NEXT
WEEK. THE MAIN FORECAST CHALLENGE WILL BE EMBEDDED SHORTWAVES
TRACKING THROUGH THIS ZONAL FLOW REGIME AND POTENTIAL PRECIPITATION
FOR THE FORECAST AREA. LONG TERM MODEL SOLUTIONS DIFFER WITH THE
HANDLING OF THESE SYSTEMS. WENT WITH A CONSENSUS BLEND APPROACH
WHICH YIELDED SLIGHT CHANCE POPS WEDNESDAY THROUGH THE END OF THE
PERIOD. HONED THESE POPS DOWN TO WEDNESDAY AND WED NIGHT
TIMEFRAME...WHICH QUICK MOVING WAVE TRACKS SOMEWHERE THROUGH THE
REGION...BUT KEPT POPS LESS THAN 20 PERCENT. WENT WITH A CONTINUED
DRY FORECAST THURSDAY AND THURSDAY NIGHT...BUT KEPT THE CONSENSUS
BLEND SOLUTION FOR FRIDAY WITH VERY LOW CHANCE POPS. TOWARD THE END
OF NEXT WEEK...THE OVERALL PATTERN BECOMES MORE AMPLIFIED AS STRONG
EPAC UPPER JET BUCKLES...WITH DEEPER TROUGHING OVER THE WRN CONUS
AND DOWNSTREAM ERN CONUS RIDGING. WHEN THIS ENERGY EJECTS THROUGH
THE REGION SOMETIME TOWARDS THE END OF THE WEEK/NEXT WEEKEND...THIS
WOULD INCREASE PRECIPITATION CHANCES GREATLY. HOWEVER LONG RANGE
MODELS DIFFER GREATLY WITH TIMING/EVOLUTION OF THIS SYSTEM...WHICH
COULD BRING A DECENT RAINFALL TO THE AREA DEPENDING ON THE
EVOLUTION. FOR NOW...WITH STICK WITH THE LOW CHANCE POPS FOR
FRIDAY...BUT THIS WILL BE THE TIME PERIOD TO WATCH FOR THE NEXT
CHANCE OF A DECENT RAINFALL FOR THE REGION.
OTHERWISE...TEMPS THROUGH THE PERIOD WILL BE MILD FOR EARLY/MID
DECEMBER STANDARDS...WITH HIGHS IN THE LOW TO MID 40S SUNDAY THROUGH
TUESDAY...AND MID TO UPPER 40S AND POSSIBLE 50S LATER IN THE PERIOD.
LOW TEMPS THROUGH THE PERIOD WILL START OUT AT OR BELOW FREEZING SAT
NIGHT AND SUN NIGHT...THEN WARMING THROUGH THE 30S EACH NIGHT
THROUGH THE END OF THE PERIOD. THIS WOULD YIELD POTENTIAL AVERAGE
TEMPS NEARLY 10 DEGREES ABOVE NORMAL BY THE END OF THE FORECAST
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1234 AM EST SAT DEC 5 2015
MOISTURE AND LOW CLOUDS REMAIN TRAPPED UNDER THE BASE OF A
SUBSIDENCE INVERSION WHERE DAYTIME HEATING HAS BEEN INSUFFICIENT
TO MIX OUT THIS LAYER. EARLY TONIGHT...THE AREA OF LOW CLOUDS AND
FOG HAS EXPANDED RAPIDLY. GIVEN THE LATEST OBSERVATIONS AND
TRENDS...HAVE MADE TAFS MUCH MORE PESSIMISTIC WITH DENSE FREEZING
FOG BY LATE TONIGHT. MUCH UNCERTAINTY HOW MUCH SKIES WILL BE ABLE
TO CLEAR OUT...AND SUBSEQUENTLY THE POSSIBILITY OF THE RETURN OF
LOW CLOUDS AND FOG AGAIN TONIGHT. AT THIS POINT...GIVEN
PERSISTENCE IN AN STAGNANT PATTERN...HAVE INTRODUCED IFR CIGS
AFTER 03Z TONIGHT. AGAIN...THERE IS MUCH UNCERTAINTY WITH THIS
TIMING WITH THESE CONDITIONS.
&&
.UPDATE...
ISSUED AT 102 AM EST SAT DEC 5 2015
MOISTURE AND LOW CLOUDS REMAIN TRAPPED UNDER THE BASE OF A
SUBSIDENCE INVERSION WHERE DAYTIME HEATING HAS BEEN INSUFFICIENT
TO MIX OUT THIS LAYER. EARLY TONIGHT...THE AREA OF LOW CLOUDS AND
FOG HAS EXPANDED RAPIDLY. GIVEN THE LATEST OBSERVATIONS AND
TRENDS AND WITH COORDINATION OF SOME OF ADJACENT OFFICES HAVE
ISSUED A FREEZING FOG ADVISORY UNTIL 10 AM.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...FREEZING FOG ADVISORY UNTIL 10 AM EST /9 AM CST/ THIS MORNING
FOR INZ003>009-012>018-020-022>027-032>034.
MI...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ077>081.
OH...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ001-
002-004-005-015-016-024-025.
LM...NONE.
&&
$$
SYNOPSIS...FISHER/SKIPPER
SHORT TERM...FISHER
LONG TERM...NG
AVIATION...SKIPPER
UPDATE...SKIPPER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1139 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 441 AM CST SAT DEC 5 2015
THE FOG HAS FILLED IN AND THE EDGE IS NOW ALONG A LINE FROM
GENESEO TO MOUNT CARROLL TO FREEPORT AND CONTINUING TO EXPAND
WEST. IT BEGAN TO SHOW A MORE DISTINCTIVE PUSH TO THE WEST OVER
THE PAST FEW HOURS...ESPECIALLY OVER THE NORTHERN PART OF THE
AREA. THEREFORE...DID EXPAND THE ADVISORY A TIER OF COUNTIES TO
THE WEST. THE FOG IS NOW CLOSE TO WHERE THE HRRR MODEL HAS BEEN
INDICATING IT WOULD REACH SO NOT ANTICIPATING THE NEED TO EXPAND
ANY FURTHER WEST AT THIS TIME. ALSO...THERE IS A DIMINISHING TREND
IN THE FOG ALONG AND EAST OF HIGHWAY 40 AND INTERSTATE 155 FROM
BRADFORD TO SOUTH OF PEORIA AND IF THIS CONTINUES TO ERODE THE FOG
FROM THE MIDDLE OUT...THE ADVISORY WOULD LIKELY BE NEEDED TO BE
CANCELLED EARLY. HOWEVER MODELS ARE STILL STUCK ON THE IDEA OF THE
FOG STICKING AROUND UNTIL EARLY AFTERNOON IN ALL AREAS. BELIEVE
THE MODELS CONTINUE TO BE OVERDONE AND FOG WILL BE ERODED BY LATE
THIS MORNING.
&&
.SYNOPSIS...
ISSUED AT 345 AM CST SAT DEC 5 2015
AT 09Z WATER VAPOR IMAGERY SHOWED BROAD RIDGING OVER
THE EASTERN PART OF THE CONUS WHICH EXTENDED THROUGH ONTARIO. A WEAK
SHORTWAVE WAS NOTED FROM THE EASTERN DAKOTAS THROUGH THE MID
MISSISSIPPI RIVER VALLEY WITH A BROAD LONGWAVE TROUGH IN PLACE
ACROSS THE WESTERN HALF OF THE CONUS. AT THE SURFACE...HIGH PRESSURE
WAS IN PLACE OVER OHIO WITH WEAK ANTI-CYCLONIC FLOW PUSHING ACROSS
ILLINOIS. A TROUGH OF LOW PRESSURE WAS IN PLACE ACROSS THE HIGH
PLAINS...LEADING TO AN INCREASING PRESSURE GRADIENT GOING WEST FROM
ILLINOIS THROUGH THE PLAINS. THIS LED TO A CHANGE IN LOW LEVEL FLOW
FROM THE SOUTHWEST...AND LESSER INFLUENCE FROM THE EASTERN AIRMASS.
FOG WAS ABUNDANT IN AREAS UNDER THE INFLUENCE OF THE SURFACE HIGH
WITH DENSE FOG BEING OBSERVED ACROSS MUCH OF ILLINOIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT DEC 5 2015
PRIMARY CONCERNS WITH THIS FORECAST CYCLE IS WITH FOG THIS MORNING
AND TEMPERATURES TODAY. THEN AGAIN WITH FOG POTENTIAL AGAIN TONIGHT.
THE FOG CONTINUES TO EXPAND WESTWARD BUT THE LEADING EDGE DOESN/T
SEEM TO BE MAKING MUCH MORE PROGRESS WEST OVER THE PAST HOUR AND
HAS MAINLY BEEN FILLING IN. SO...MAY BE CLOSE TO WHERE IT WILL END
UP...MAINLY EAST OF A LINE FROM MACOMB TO GENESEO TO FREEPORT. THE
MORE WIDESPREAD FOG REMAINS OVER BUREAU AND PUTNAM
COUNTIES...ALTHOUGH HAS EDGED INTO WHITESIDE AND HENRY COUNTIES.
AT THIS POINT...WILL FOREGO EXPANDING THE ADVISORY AS THE FOG IS
NOT QUITE AS WIDESPREAD BUT WILL CONTINUE TO WATCH ITS BEHAVIOR
THROUGH THE MORNING. AS FOR TIMING OF THE FOG LIFTING. WITH THE
TIME OF YEAR AND NOT MUCH FOR LOW LEVEL FLOW THIS MORNING...NOT
EXPECTING A FAST CLEARING OF THE FOG AND WILL LIKELY CONTINUE INTO
MID OR EVEN LATE MORNING...BUT WITH THE LOCAL AREA ON THE
EDGE...WILL LIKELY SEE THE FOG LIFTED EARLIER THAN AREAS TO THE
EAST.
TEMPERATURES OVER THE EASTERN PART OF THE FORECAST AREA WILL BE
HEAVILY INFLUENCED BY THE FOG THE LONGER IT PERSISTS. DID GO A BIT
COOLER FOR HIGHS WHERE FOG/CLOUDS WILL BE IN PLACE THROUGH THE
MORNING...DELAYING THE WARMING. ELSEWHERE...SHOULD SEE A GOOD WARM-
UP FOR THIS TIME OF YEAR AS DECENT MIXING SHOULD OCCUR TO AROUND
950MB WHICH WOULD BRING TEMPERATURES INTO THE UPPER 40S AND LOW 50S.
THEN FOR TONIGHT...AS THE TROUGH OF LOW PRESSURE APPROACHES FROM THE
WEST...SO WILL CLOUDS. BUT MOST MODELS INDICATE MANY WILL STAY WEST
OF THE FORECAST ARE THROUGH MUCH OF THE NIGHT. THERE ARE INDICATIONS
THOUGH THAT FOG WILL REDEVELOP ACROSS ILLINOIS DURING THE EVENING
AND THEN EXPAND WEST OVERNIGHT AND BACK INTO THE EASTERN PART OF THE
FORECAST AREA. DON/T HAVE HIGH CONFIDENCE ON ANYTHING DENSE...BUT
DID INCLUDE FOG MENTION IN THE FORECAST FOR THESE AREAS TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT DEC 5 2015
A CLOSED UPPER LOW CONTINUES TO BE FORECAST BY ALL MODELS TO
PROGRESS THROUGH IOWA AND ILLINOIS DURING THE DAY SUNDAY INTO EARLY
SUNDAY EVENING. AS HAS BEEN THE CASE IN THE PAST FEW DAYS OF MODEL
DATA...IT APPEARS THIS SYSTEM WILL HAVE ACCESS TO LITTLE IF ANY
MOISTURE FROM THE SOUTH. THE SMALL AMOUNT OF MOISTURE DRAWN FROM
ITS PACIFIC ORIGINS WILL LIKELY WRING OUT IN LIGHT RAIN...WITH QPF
AMOUNTS UNDER 1 TENTH OF AN INCH. WE WILL CONTINUE WITH FAIRLY LOW
POPS FOR WHAT COULD END UP BEING A HIGH POP LOW QPF EVENT IF
SATURATION CAN BE ACHIEVED OVER A LARGER PORTION OF THE CWA. UNDER
THE HIGH CONFIDENCE CLOUDY SKIES...SUNDAY AFTERNOON TEMPERATURES
SHOULD BE HELD TO THE LOWER 40S IN MOST LOCATIONS...AND UNDER
SIMILARLY MOSTLY CLOUDY SKIES SUNDAY NIGHT...LOWS SHOULD ONLY FALL
TO THE THE LOWER 30S. IT BEARS WATCHING LATE SUNDAY NIGHT AS THE MID
CLOUDS MOVE OFF TO THE EAST...SOME SHALLOW FOG DEVELOPMENT APPEARS
POSSIBLE...AND THAT COULD BE DENSE IF WIDESPREAD LIGHT RAIN DOES
OCCUR SUNDAY.
WEAK HIGH PRESSURE WILL MOVE OVER THE AREAS MONDAY MORNING...WITH
RETURN FLOW QUICKLY DEVELOPING FOR MONDAY NIGHT AND TUESDAY. HIGHS
MONDAY AND TUESDAY SHOULD ONCE AGAIN REACH THE MID 40S TO NEAR 50.
ANOTHER WEAK UPPER LOW SHOULD BRUSH THE REGION TUESDAY AFTERNOON AND
NIGHT...WITH LOW POPS NORTH FOR LIGHT RAIN. FOLLOWING THAT...A MORE
SIGNIFICANT DEEP PROGRESSIVE UPPER TROF WILL SWEEP THROUGH THE
MIDWEST BY LATE IN THE WORK WEEK. AHEAD OF THIS FRONT/TROF
PASSAGE...AT LEAST TWO DAYS OF SUSTAINED WAA WILL TAKE PLACE. THIS
WILL EVENTUALLY DRAW UP SOME DEEPER MOISTURE THAN WE WILL HAVE SEEN
IN OVER WEEK...AND WITH THAT...A CHANCE FOR SEASONALLY SIGNIFICANT
RAINFALL IS GROWING FOR THE THURSDAY AND FRIDAY TIME PERIOD. THE
ATMOSPHERE WOULD CERTAINLY BE MILD ENOUGH FOR ALL RAIN DURING THOSE
TWO DAYS. HIGHS WOULD EASILY REACH THE MID 40S TO AROUND 50 IN THE
MOIST AIRMASS...WITH LOWS IN THE MID 30S TO MID 40S.
ERVIN
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1136 AM CST SAT DEC 5 2015
VFR CONDITIONS TO PREVAIL THE NEXT 24 HOURS WITH INCREASING HIGH
CLOUDS TONIGHT AHEAD OF A WEAK UPPER LEVEL DISTURBANCE. SOUTH WINDS
OF 5 TO 15 KTS TO CONTINUE THROUGH MID DAY SUNDAY. AFTER 06/14Z...ISOLATED
TO SCATTERED COVERAGE OF LIGHT RAIN OR SPRINKLES POSSIBLE AT THE TERMINALS
WITH COVERAGE AND CONFIDENCE TOO LOW TO INCLUDE IN TAFS EXCEPT FOR VICINITY
WORDING.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...BROOKS
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...BROOKS
AVIATION...NICHOLS
AREA FORECAST DISCUSSION...UPDATED
NWS QUAD CITIES IA IL
515 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 441 AM CST SAT DEC 5 2015
THE FOG HAS FILLED IN AND THE EDGE IS NOW ALONG A LINE FROM
GENESEO TO MOUNT CARROLL TO FREEPORT AND CONTINUING TO EXPAND
WEST. IT BEGAN TO SHOW A MORE DISTINCTIVE PUSH TO THE WEST OVER
THE PAST FEW HOURS...ESPECIALLY OVER THE NORTHERN PART OF THE
AREA. THEREFORE...DID EXPAND THE ADVISORY A TIER OF COUNTIES TO
THE WEST. THE FOG IS NOW CLOSE TO WHERE THE HRRR MODEL HAS BEEN
INDICATING IT WOULD REACH SO NOT ANTICIPATING THE NEED TO EXPAND
ANY FURTHER WEST AT THIS TIME. ALSO...THERE IS A DIMINISHING TREND
IN THE FOG ALONG AND EAST OF HIGHWAY 40 AND INTERSTATE 155 FROM
BRADFORD TO SOUTH OF PEORIA AND IF THIS CONTINUES TO ERODE THE FOG
FROM THE MIDDLE OUT...THE ADVISORY WOULD LIKELY BE NEEDED TO BE
CANCELLED EARLY. HOWEVER MODELS ARE STILL STUCK ON THE IDEA OF THE
FOG STICKING AROUND UNTIL EARLY AFTERNOON IN ALL AREAS. BELIEVE
THE MODELS CONTINUE TO BE OVERDONE AND FOG WILL BE ERODED BY LATE
THIS MORNING.
&&
.SYNOPSIS...
ISSUED AT 345 AM CST SAT DEC 5 2015
AT 09Z WATER VAPOR IMAGERY SHOWED BROAD RIDGING OVER
THE EASTERN PART OF THE CONUS WHICH EXTENDED THROUGH ONTARIO. A WEAK
SHORTWAVE WAS NOTED FROM THE EASTERN DAKOTAS THROUGH THE MID
MISSISSIPPI RIVER VALLEY WITH A BROAD LONGWAVE TROUGH IN PLACE
ACROSS THE WESTERN HALF OF THE CONUS. AT THE SURFACE...HIGH PRESSURE
WAS IN PLACE OVER OHIO WITH WEAK ANTI-CYCLONIC FLOW PUSHING ACROSS
ILLINOIS. A TROUGH OF LOW PRESSURE WAS IN PLACE ACROSS THE HIGH
PLAINS...LEADING TO AN INCREASING PRESSURE GRADIENT GOING WEST FROM
ILLINOIS THROUGH THE PLAINS. THIS LED TO A CHANGE IN LOW LEVEL FLOW
FROM THE SOUTHWEST...AND LESSER INFLUENCE FROM THE EASTERN AIRMASS.
FOG WAS ABUNDANT IN AREAS UNDER THE INFLUENCE OF THE SURFACE HIGH
WITH DENSE FOG BEING OBSERVED ACROSS MUCH OF ILLINOIS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT DEC 5 2015
PRIMARY CONCERNS WITH THIS FORECAST CYCLE IS WITH FOG THIS MORNING
AND TEMPERATURES TODAY. THEN AGAIN WITH FOG POTENTIAL AGAIN TONIGHT.
THE FOG CONTINUES TO EXPAND WESTWARD BUT THE LEADING EDGE DOESN/T
SEEM TO BE MAKING MUCH MORE PROGRESS WEST OVER THE PAST HOUR AND
HAS MAINLY BEEN FILLING IN. SO...MAY BE CLOSE TO WHERE IT WILL END
UP...MAINLY EAST OF A LINE FROM MACOMB TO GENESEO TO FREEPORT. THE
MORE WIDESPREAD FOG REMAINS OVER BUREAU AND PUTNAM
COUNTIES...ALTHOUGH HAS EDGED INTO WHITESIDE AND HENRY COUNTIES.
AT THIS POINT...WILL FOREGO EXPANDING THE ADVISORY AS THE FOG IS
NOT QUITE AS WIDESPREAD BUT WILL CONTINUE TO WATCH ITS BEHAVIOR
THROUGH THE MORNING. AS FOR TIMING OF THE FOG LIFTING. WITH THE
TIME OF YEAR AND NOT MUCH FOR LOW LEVEL FLOW THIS MORNING...NOT
EXPECTING A FAST CLEARING OF THE FOG AND WILL LIKELY CONTINUE INTO
MID OR EVEN LATE MORNING...BUT WITH THE LOCAL AREA ON THE
EDGE...WILL LIKELY SEE THE FOG LIFTED EARLIER THAN AREAS TO THE
EAST.
TEMPERATURES OVER THE EASTERN PART OF THE FORECAST AREA WILL BE
HEAVILY INFLUENCED BY THE FOG THE LONGER IT PERSISTS. DID GO A BIT
COOLER FOR HIGHS WHERE FOG/CLOUDS WILL BE IN PLACE THROUGH THE
MORNING...DELAYING THE WARMING. ELSEWHERE...SHOULD SEE A GOOD WARM-
UP FOR THIS TIME OF YEAR AS DECENT MIXING SHOULD OCCUR TO AROUND
950MB WHICH WOULD BRING TEMPERATURES INTO THE UPPER 40S AND LOW 50S.
THEN FOR TONIGHT...AS THE TROUGH OF LOW PRESSURE APPROACHES FROM THE
WEST...SO WILL CLOUDS. BUT MOST MODELS INDICATE MANY WILL STAY WEST
OF THE FORECAST ARE THROUGH MUCH OF THE NIGHT. THERE ARE INDICATIONS
THOUGH THAT FOG WILL REDEVELOP ACROSS ILLINOIS DURING THE EVENING
AND THEN EXPAND WEST OVERNIGHT AND BACK INTO THE EASTERN PART OF THE
FORECAST AREA. DON/T HAVE HIGH CONFIDENCE ON ANYTHING DENSE...BUT
DID INCLUDE FOG MENTION IN THE FORECAST FOR THESE AREAS TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT DEC 5 2015
A CLOSED UPPER LOW CONTINUES TO BE FORECAST BY ALL MODELS TO
PROGRESS THROUGH IOWA AND ILLINOIS DURING THE DAY SUNDAY INTO EARLY
SUNDAY EVENING. AS HAS BEEN THE CASE IN THE PAST FEW DAYS OF MODEL
DATA...IT APPEARS THIS SYSTEM WILL HAVE ACCESS TO LITTLE IF ANY
MOISTURE FROM THE SOUTH. THE SMALL AMOUNT OF MOISTURE DRAWN FROM
ITS PACIFIC ORIGINS WILL LIKELY WRING OUT IN LIGHT RAIN...WITH QPF
AMOUNTS UNDER 1 TENTH OF AN INCH. WE WILL CONTINUE WITH FAIRLY LOW
POPS FOR WHAT COULD END UP BEING A HIGH POP LOW QPF EVENT IF
SATURATION CAN BE ACHIEVED OVER A LARGER PORTION OF THE CWA. UNDER
THE HIGH CONFIDENCE CLOUDY SKIES...SUNDAY AFTERNOON TEMPERATURES
SHOULD BE HELD TO THE LOWER 40S IN MOST LOCATIONS...AND UNDER
SIMILARLY MOSTLY CLOUDY SKIES SUNDAY NIGHT...LOWS SHOULD ONLY FALL
TO THE THE LOWER 30S. IT BEARS WATCHING LATE SUNDAY NIGHT AS THE MID
CLOUDS MOVE OFF TO THE EAST...SOME SHALLOW FOG DEVELOPMENT APPEARS
POSSIBLE...AND THAT COULD BE DENSE IF WIDESPREAD LIGHT RAIN DOES
OCCUR SUNDAY.
WEAK HIGH PRESSURE WILL MOVE OVER THE AREAS MONDAY MORNING...WITH
RETURN FLOW QUICKLY DEVELOPING FOR MONDAY NIGHT AND TUESDAY. HIGHS
MONDAY AND TUESDAY SHOULD ONCE AGAIN REACH THE MID 40S TO NEAR 50.
ANOTHER WEAK UPPER LOW SHOULD BRUSH THE REGION TUESDAY AFTERNOON AND
NIGHT...WITH LOW POPS NORTH FOR LIGHT RAIN. FOLLOWING THAT...A MORE
SIGNIFICANT DEEP PROGRESSIVE UPPER TROF WILL SWEEP THROUGH THE
MIDWEST BY LATE IN THE WORK WEEK. AHEAD OF THIS FRONT/TROF
PASSAGE...AT LEAST TWO DAYS OF SUSTAINED WAA WILL TAKE PLACE. THIS
WILL EVENTUALLY DRAW UP SOME DEEPER MOISTURE THAN WE WILL HAVE SEEN
IN OVER WEEK...AND WITH THAT...A CHANCE FOR SEASONALLY SIGNIFICANT
RAINFALL IS GROWING FOR THE THURSDAY AND FRIDAY TIME PERIOD. THE
ATMOSPHERE WOULD CERTAINLY BE MILD ENOUGH FOR ALL RAIN DURING THOSE
TWO DAYS. HIGHS WOULD EASILY REACH THE MID 40S TO AROUND 50 IN THE
MOIST AIRMASS...WITH LOWS IN THE MID 30S TO MID 40S.
ERVIN
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1123 PM CST FRI DEC 4 2015
AREA OF LOW CLOUDS AND FOG EXPANDING NORTHWARD INTO CENTRAL AND
NORTHERN ILLINOIS THIS EVENING WILL LIKELY REMAIN EAST OF THE
TERMINALS THROUGH TONIGHT. VISIBILITIES WERE BEGINNING TO DROP
SOME WELL WEST OF THE STRATUS...AND IT IS LOOKING LIKELY THAT AT
LEAST MVFR FOG WILL DEVELOP AT ALL SITES...WHICH HAS BEEN ADDED IN
THE LATEST FORECASTS FOR LATE TONIGHT THROUGH MID MORNING
SATURDAY. THERE IS A CONTINUED LOW POTENTIAL THAT THE IFR
CONDITIONS COULD SEEP INTO THE BRL AND MLI TERMINALS TOWARD
SUNRISE. VFR CONDITIONS ARE LIKELY FOR SATURDAY AFTERNOON THROUGH
EVENING WITH LIGHT SOUTHERLY WINDS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR BUREAU-CARROLL-HENRY
IL-PUTNAM-STEPHENSON-WHITESIDE.
MO...NONE.
&&
$$
UPDATE...BROOKS
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...BROOKS
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
931 PM EST SUN DEC 6 2015
.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN DRY WEATHER TONIGHT. A LOW PRESSURE
SYSTEM MAY BRING LIGHT RAIN TO AREAS SOUTH OF PITTSBURGH ON
MONDAY. DRY AND MILD AGAIN ON TUESDAY UNDER WEAK HIGH PRESSURE.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 930PM...THERE WAS QUITE A VARIATION IN HOURLY TEMPERATURES
ACROSS THE FORECAST AREA. WHERE HIGH CLOUDS HAVE MOVED TO THE
EAST...TEMPERATURES HAD ALREADY DROPPED INTO THE LOW-MID 30S.
MEANWHILE...TEMPERATURES ARE STILL IN THE LOW 40S AT HLG AND AGC.
THINK THAT THIS TREND OF A QUICK DROP IN TEMPERATURES WILL
CONTINUE ACROSS THE REST OF THE FORECAST AS SKIES CLEAR OUT
ELSEWHERE. CONSIDERING PHD AND ZZV ALREADY DROPPED TO THEIR
FORECAST LOWS...HAVE CUT OVERNIGHT LOWS ABOUT 5 DEGREES IN ALL
LOCATIONS. HOWEVER...HAVE LOW CONFIDENCE IN THIS PART OF THE
FORECAST. DEPENDING ON HOW QUICKLY NEXT ROUND OF CLOUDS MOVE IN
FROM THE WEST AND WARM ADVECTION KICKS IN...UPDATED FORECAST
COULD BE TOO WARM OR COLD. WILL KEEP FOG OUT OF THE FORECAST.
AS FOR PRECIPITATION...CANNOT RULE OUT THE POSSIBILITY THAT NEXT
SYSTEM COULD START AS SNOW FOR A SHORT PERIOD OF TIME BEFORE
QUICKLY CHANGING OVER TO RAIN. HOWEVER...21Z SREF...00Z NAM...AND
01Z HRRR HAVE SHIFTED PRECIPITATION FARTHER SOUTH...AND HAVE
UPDATED THE FORECAST TO ACCOUNT FOR THIS TREND. DID NOT SHIFT
FORECAST AS FAR SOUTH AS MODELS INDICATED TO ALLOW MIDNIGHT SHIFT
THE CHANCE TO SEE HOW RADAR TRENDS DEVELOP. PREVIOUS DISCUSSION
FOLLOWS.
NAM/GFS IN GOOD AGREEMENT ON TRACKING H500 LOW ACROSS THE CWA ON
MONDAY. MODELS CONTINUE TO KEEP THE BULK OF THE MOISTURE SOUTH OF
THE MASON-DIXON LINE IN THE BASE OF THE ASSOCIATED TROUGH. ADDED A
BIT MORE OF A GRADIENT TO THE POP FIELDS...RANGING FROM SLIGHT
CHANCE NEAR PIT TO HIGH CHANCE IN THE SOUTHEAST RIDGE COUNTIES. IN
ANY CASE...LACK OF DEEP MOISTURE AND THE PROGRESSIVE NATURE OF THE
SYSTEM SHOULD KEEP RAIN TOTALS LOW...GENERALLY LESS THAN A TENTH
OF AN INCH. NORTH OF PIT...SCT-BKN MID DECK CLOUDS ARE FORESEEN.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
SERIES OF SHORTWAVES WILL MOVE ACROSS THE REGION THROUGH THE
SHORT-TERM. AFTER THE PASSAGE OF THE SYSTEM ON MONDAY...A WEAK
WAVE AND THEN A MORE AMPLIFIED SHORTWAVE ARE PROGGED TO CROSS TUES
AND WED. AT THIS POINT THERE IS LITTLE MOISTURE OR SUPPORT UNTIL
THE MORE AMPLIFIED SHORTWAVE ARRIVES WEDNESDAY. WITH THIS IN
MIND...WILL CONTINUE TO CARRY A DRY FORECAST TUESDAY AND CHANCE
POPS ON WEDNESDAY.
TEMPERATURES ARE IN QUESTION THROUGH THE PERIOD...MAINLY DUE TO
THE VARIABILITY IN THE TEMPERATURES ALOFT...CLOUD COVER...AND
STRONG ADVECTION NOT ANTICIPATED UNTIL LATER IN THE WEEK.
THUS...OPTED TO STAY CLOSE TO A BLEND OF MAV/MET GUIDANCE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THERE REMAINS SOME UNCERTAINTY IN THE FORECAST...MAINLY IN REGARD
TO TIMING FOR THE SYSTEM INTO NEXT WEEKEND. UPPER LEVEL PATTERN
CONTINUES TO SUPPORT FAST MOVING SHORTWAVES BUT A TRANSITION TO A
MORE AMPLIFIED TROUGH/RIDGE PATTERN IS ANTICIPATED. THE BUILDING
TROUGH IN THE WEST SHOULD SUPPORT WARMING IN THE EAST UNDER A
STRENGTHENING RIDGE. THIS HAS BEEN CONSISTENT...SO LITTLE CHANGE
WAS MADE TO TEMPERATURES BASED OFF OF NATIONAL GUIDANCE.
THE DETERMINISTIC GFS HAS SLOWED SIGNIFICANTLY FROM PREVIOUS RUNS
ON THE PROGRESSION OF A SYSTEM FOR THE WEEKEND...WHICH IS NOT
SHOWN SO MUCH IN THE ENSEMBLE GUIDANCE. WILL MAKE NOTE OF THIS
CHANGE...BUT WILL STAY CLOSER TO PREVIOUS MODEL RUNS AND ENSEMBLE
GUIDANCE.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
PERIDAWN FOG WITH MVFR VSBY IS EXPECTED...BUT VFR SHOULD BE
PREDOMINATE AS APPROACHING LOW PRES SHUNTS MID LVL MSTR AND
WARMTH OVR UPR OH VALLEY TERMINALS ON MONDAY MRNG. THE EXCEPTION
MAY BE AT ZZV AND MGW WHERE MVFR CONDITIONS MAY LINGER WITH LGT
RAIN DVLPMNT UNDR THE CROSSING LOW.
.OUTLOOK...MONDAY NIGHT THROUGH FRIDAY/...
THE NEXT CHANCE FOR RESTRICTIONS WILL COME WITH AN UPPER DISTURBANCE
ON WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
804 PM EST SUN DEC 6 2015
.UPDATE...
ANOTHER CHALLENGING NIGHT FOR DELINEATING BOTH THE SCOPE AND
LOCATION OF STRATUS VERSUS DENSE FOG. A RATHER AGGRESSIVE
RESPONSE ALREADY UNDERWAY AGAIN TONIGHT AS THE NEAR SURFACE
ENVIRONMENT QUICKLY SATURATES. 23Z HRRR VISIBILITY OUTPUT ON
TARGET WITH CURRENT CONDITIONS...AND POINTS TOWARD A SIGNIFICANT
EXPANSION OF FOG NORTH OF I-69 THROUGH 06Z. ALREADY SIGNS OF THIS
FROM THE THUMB BACK INTO SAGINAW. ANOTHER REGION OF LOWER
VISIBILITY NOTED CENTERED BETWEEN THE I-96 CORRIDOR AND THE OHIO
BORDER. WHILE VISIBILITY HAS TANKED ACROSS PORTIONS OF THIS
CORRIDOR...NOW NOTING A SUBTLE BUT PERHAPS IMPORTANT SHIFT IN WIND
TO LIGHT NORTHWESTERLY. THE ADDED SLIGHT DOWNSLOPE OFF THE GLACIAL
RIDGE MAY VERY WELL LEAVE THIS DENSE FOG AS A TEMPORARY/MORE
LOCALIZED ISSUE...WITH A TREND TOWARD MORE OF A LOW STRATUS ISSUE.
WILL CLOSELY MONITOR VISIBILITY TRENDS MOVING FORWARD TO
DETERMINE THE NEED FOR AN ADVISORY ACROSS THIS CORRIDOR. GREATER
CONCERN CURRENTLY ACROSS THE THUMB AND TRI-CITIES...GIVEN
SUPPORTIVE MODEL AND SATELLITE EVIDENCE TO ADD CONFIDENCE FOR A
WIDESSPREAD DENSE FOG EVENT OVERNIGHT. WILL GO AHEAD WITH AN
ADVISORY FOR THIS CORRIDOR...WITH ROOM TO EXPAND SHOULD CONDITIONS
WARRANT FOR POINTS TO THE SOUTH.
&&
.AVIATION...ISSUED 647 PM EST SUN DEC 6 2015
CHALLENGING ENVIRONMENT AGAIN TONIGHT FOR AVIATION AS SUFFICIENT
NEAR SURFACE MOISTURE AT THE BASE OF A DEEP INVERSION WILL ONCE
AGAIN LEAD TO A COMBINATION OF LOW STRATUS AND FOG DEVELOPMENT.
EXISTING LIFR DECK CENTERED OVER YIP NOW SHOWING SIGNS OF
EXPANSION...A TREND THAT WILL LIKELY SOLIDIFY A WIDESPREAD LIFR
CONDITION TONIGHT FROM THE DETROIT CORRIDOR NORTH INTO PTK.
ADDITIONAL STRATUS OVER MBS BUILDING SOUTHEAST WILL MAINTAIN THE
POTENTIAL FOR LIFR/IFR TO WORK DOWN INTO FLINT OVERNIGHT. ADDITIONAL
MOISTURE TIED TO AN INBOUND TROUGH NOW SHIFTING ACROSS LAKE MICHIGAN
WILL ARRIVE BY MID MORNING. THIS MOISTURE WILL REINFORCE THE
EXISTING LOW STRATUS FOR MONDAY...BUT FAVOR SOME IMPROVEMENT IN VSBY
AS FLOW TURNS TO NORTHWEST.
FOR DTW...LIFR STRATUS/FOG NOW IN PLACE WILL HOLD FIRM THROUGHOUT
THE NIGHT. THE EMERGENCE OF A LIGHT NORTHWEST FLOW BY MID MORNING
WILL PROMOTE SOME IMPROVEMENT IN CONDITIONS BEYOND 10Z. IFR LEVEL
RESTRICTIONS APPEAR LIKELY WELL INTO MONDAY UNDER CONTINUED LOW
STRATUS.
//DTW THRESHOLD PROBABILITIES...
* HIGH IN VSBY/CIGS BELOW 1/2SM AND/OR 200 FT TONIGHT.
* HIGH IN CIGS BELOW 5000 FT TONIGHT AND MONDAY.
&&
.PREV DISCUSSION...ISSUED 306 PM EST SUN DEC 6 2015
DISCUSSION...
NEARLY A CARBON COPY RESULT OF SATURDAY ACROSS SOUTHEAST LOWER
MICHIGAN - WITH A STUBBORN STRATUS DECK BANKED UP AGAINST THE
GLACIAL RIDGE BENEATH A VERY STRONG NEAR SURFACE THERMAL INVERSION.
AS A RESULT...THESE CLOUDS HAVE KEPT TEMPS DOWN SIGNIFICANTLY ACROSS
NORTHERN AND WESTERN SECTIONS OF THE METRO REGION. AN ADDITIONAL
MORE EXPANSIVE AREA OF STRATUS OVER THE CENTRAL LOWER PENINSULA HAS
BEEN AFFECTING THE MIDLAND REGION. ELSEWHERE...AMPLE SUN HAS
PROPELLED TEMPERATURES WELL INTO THE 40S.
A WELL DEFINED MID-TROPOSPHERIC WAVE IS CURRENTLY CYCLING ACROSS
CENTRAL ILLINOIS AND WILL PASS TO THE SOUTH OF LOWER MICHIGAN
TONIGHT. AN INVERTED SURFACE TROUGH EXTENDING NORTHWARD ACROSS
WISCONSIN...IN CONJUNCTION WITH A NARROW ELEVATED PV FILAMENT
ATTACHING THE WAVE TO THE PARENT RESERVOIR OVER THE HUDSON BAY
REGION...WILL SLIDE THROUGH THE REGION TONIGHT. THIS WILL SERVE TO
TURN THE LIGHT FLOW TO MORE WESTERLY AND ALLOW FOR ADDITIONAL LOW-
LEVEL MOISTURE ADVECTION BENEATH THE PERSISTENT INVERSION LAYER.
SPECIFICALLY...A SUBSTANTIAL STRATUS PRESENCE IS NOTED UPSTREAM IN
THE WAKE OF THE SURFACE TROUGH.
WITH THE LOSS OF INSOLATION EARLY THIS EVENING...EXPECT THE CURRENT
LOW CLOUD SHIELDS OVER AREA TO START TO EXPAND ONCE AGAIN. FOG
DEVELOPMENT IS ALSO VERY LIKELY AS RADIATIONAL COOLING SHOULD BE
MORE EFFICIENT TONIGHT DUE TO A LESSER DEGREE OF ELEVATED MOISTURE
INTERCEPTING THE OUTGOING OPTICAL PATH. THE HRRR...RAP...AND TO A
LESSER EXTENT NAM GUIDANCE ALL OFFER SOME DEPICTION OF BOTH AN
EXPANDING CLOUD/FOG SCENARIO IN COMBINATION WITH THE UPSTREAM NEAR
SURFACE MOISTURE ADVECTING INTO THE REGION OVERNIGHT.
UNFORTUNATELY...THE VERY LOW CLOUDS WILL LIKELY PERSIST EVERYWHERE
ON MONDAY...WHICH WILL GREATLY REDUCE MAX TEMPERATURE POTENTIAL. THE
NAM AND REGIONAL GEM ARE OFFERING A VERY GLOOMY PICTURE RIGHT ON
INTO TUESDAY. GIVEN THE INABILITY TO ERASE THE OMNIPRESENT
INVERSION...A MORE PESSIMISTIC DEPICTION IS THE MOST LIKELY OUTCOME.
THEREFORE...HAVE LOWERED HIGH TEMPERATURES ON MONDAY AND TUESDAY
APPRECIABLY - CERTAINLY MUCH MORE THAN ANY GUIDANCE OFFERED BY THE
GFS FAMILY...WHICH HAS NOT OFFERED ANY SKILL THUS FAR.
THE NEXT CHANCE FOR MEASURABLE PRECIPITATION WILL COME LATER IN THE
DAY ON TUESDAY AS SOME SEMBLANCE OF MID-LEVEL THETA-E ADVECTION
COMMENCES WITH A WEAK UPPER-LEVEL RIPPLE. THIS IS ESPECIALLY TRUE
ACROSS THE SAGINAW VALLEY AND THUMB REGIONS. THE NEXT WAVE OF DEEPER
THETA-E ADVECTION ARRIVES EARLY WEDNESDAY WITH A MUCH BETTER
DEFINED PACIFIC ORIGIN SHORTWAVE. THE MOISTURE QUALITY IS STILL
RATHER LOW - GIVEN ANY RETURN FLOW OFF THE GULF OF MEXICO IS
INACCESSIBLE.
WEAK SURFACE RIDGING WILL KEEP US DRY FOR WEDNESDAY NIGHT AND
MOST OF THURSDAY. A STRONGER LOW PRESSURE SYSTEM IS FORECASTED TO
TRACK OVER THE NORTHERN GREAT LAKES ON THURSDAY NIGHT AND INTO
FRIDAY. THIS LOW AND ASSOCIATED COLD FRONT WILL BRING ANOTHER SHOT
AT SOME RAIN SHOWERS ON THURSDAY NIGHT AND INTO EARLY FRIDAY
MORNING. FOR FRIDAY AND THE WEEKEND...THERE IS INCONSISTENCY
AMONGST THE MODELS IN REGARDS TO THE NEXT WEATHER MAKER. FOR
NOW...HAVE JUST KEPT IN HIGH CHANCE POPS /50 PERCENT/ FOR NEXT
WEEKEND UNTIL THE MODELS CAN GET A BETTER HANDLE ON THE SYSTEM.
ONE THING THAT IS FOR CERTAIN IS THAT TEMPERATURES WILL BE QUITE
WARM /850 TEMPS IN THE 5 TO 10 DEGREE CELSIUS RANGE/ WHICH WILL
RESULT IN PRECIPITATION TO BE ALL RAIN.
MARINE...
WINDS WILL VEER ACROSS THE CENTRAL LAKES REGION TONIGHT AS A WEAK
SURFACE TROUGH PASSES. SPEEDS WILL ALSO DECREASE AS WEAK HIGH
PRESSURE SLIPS IN BEHIND THE TROUGH. SOUTHWEST WINDS WILL RESUME AND
INCREASE ONCE AGAIN ON TUESDAY IN ADVANCE OF THE NEXT SYSTEM THE
RELATIVELY STABLE NEAR SURFACE CONDITIONS WILL KEEP THE WIND IN
CHECK...BUT WILL STILL APPROACH 20KTS WITH SOME GUST POTENTIAL OVER
THE OPEN WATERS AND SAGINAW BAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......MR
AVIATION.....MR
DISCUSSION...MANN/RK
MARINE.......MANN
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
640 PM EST SUN DEC 6 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 405 PM EST SUN DEC 6 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A SPLIT FLOW PATTERN ACROSS
NORTH AMERICA WITH A SRN STREAM MID LEVEL LOW OVER ILLINOIS AND THE
ACTIVE PORTION OF THE NRN STREAM BRANCH WELL TO THE NORTH THROUGH
NRN ONTARIO AND JAMES BAY. THE NRN ONTARIO SHRTWV HAS DRAGGED A WEAK
COLD FRONT THROUGH THE NRN LAKES WITH DRIER AIR AND ACYC COMBINED
WITH DAYTIME MIXING HELPING TO SCOUR OUT THE LOW CLOUDS OVER MUCH OF
UPPER MICHIGAN...EXCEPT OVER THE KEWEENAW AND THE EAST.
TONIGHT...THE MODELS SHOW MID LEVEL AND SFC RIDGING BUILDING INTO
THE WRN LAKES TONIGHT WITH PWAT VALUES DROPPING AOB 0.25 INCH OVER
MUCH OF UPPER MICHIGAN. ALTHOUGH THERE MAY BE A PERIOD OF CLEARING
INTO THIS EVENING...EXPECT THAT WITH FAVORABLE RADIATIONAL COOLING
CONDITIONS AND LINGERING LOW LEVEL MOISTURE WITH DEWPOINTS FROM LATE
AFTERNOON IN THE LOWER 30S...AREAS OF FOG WILL DEVELOP. ISOLD DENSE
FOG WILL ALSO BE POSSIBLE...BUT CONFIDENCE IN TIMING/LOCATIONS IS
NOT AS HIGH. DEVELOPING DOWNSLOPE SSW LOW LEVEL FLOW OVER THE WEST
WILL LIMIT FOG POTENTIAL IN THE WEST HALF NEAR LAKE SUPERIOR.
MONDAY...HIGHER RES MODELS 925MB RH FCST SUGGESTS THAT ADDITIONAL SW
FLOW DRY ADVECTION ALONG WITH LIMITED WINTER TIME DAYTIME WILL BE
ENOUGH TO AGAIN SCOUR OUT ANY LEFTOVER CLOUDS/FOG DURING THE MORNING.
THIS SHOULD ALLOW TEMPS TO CLIMB INTO THE LOW TO MID 40S WITH UPPER
40S WITH DOWNSLOPE FLOW NEAR LAKE SUPERIOR.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM EST SUN DEC 6 2015
MUCH OF THIS PERIOD WILL BE MARKED BY 500MB WAVES IN WHAT GENERALLY
LOOKS LIKE ZONAL FLOW...WITH A SERIES OF WEAK SFC LOWS SPINNING
ACROSS CANADA IMPACTING THE UPPER GREAT LAKES THROUGH THE WORK WEEK.
OVERALL LIGHT PRECIP IS ANTICIPATED.
BY 00Z TUESDAY THE INITIAL 500MB TROUGH WILL BE WELL TO OUR E /OVER
PA/...WITH AN EXITING RIDGE OVER THE UPPER GREAT LAKES AHEAD OF THE
NEXT TROUGH SET UP FROM N MANITOBA THROUGH MN/IA. A BROAD SFC LOW
WAS OVER MUCH OF W AND CENTRAL CANADA. THE E LOBE OF THIS TROUGH
WILL BE ACROSS N ONTARIO...DROPPING A COLD FRONT ACROSS OUR AREA.
THE RESULT WILL BE INCREASED MID AND HIGH CLOUDS THAT WILL CONTINUE
INTO EARLY WEDNESDAY MORNING. WHILE FCST MODELS DO INDICATE SOME
CHANCE OF PRECIPITATION...MUCH OF THAT IS LIGHT AND OVER THE E HALF
OF THE CWA. THERE WILL BE AS AN ADDITIONAL TROUGH IN THE BROAD
CANADIAN LOW SWINGS ACROSS S MANITOBA/ND TUESDAY AFTERNOON AND OVER
THE UPPER GREAT LAKES WEDNESDAY MORNING.
ZONAL FLOW/SLIGHT RIDGING BRIEFLY TAKES HOLD LATE WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING...WHILE THE NEXT 500MB TROUGH SETS
UP OVER S SASKATCHEWAN/MT. THE LAST AND STRONGEST PART OF THE
CANADIAN LOW WILL BE OVER S CENTRAL CANADA AT 06Z THURSDAY. LOOK FOR
THIS LOW TO SHIFT ACROSS N MN THURSDAY MORNING AND THEN ACROSS N
LAKE SUPERIOR/ONTARIO THURSDAY EVENING. THE LOW WILL CONTINUE TO
TRACK TO AROUND JAMES BAY BY 18Z FRIDAY. THERE ARE SOME
DISCREPANCIES...AS THE GFS AND CANADIAN RUNS EJECT THE LOW TO THE NE
MUCH QUICKER THAN THE 00Z RUN OF THE ECMWF FRIDAY NIGHT. THE 12Z
ECMWF SPED THE SYSTEM UP A BIT...BUT IT/S STILL ON THE SLOW SIDE.
JUST HOW MUCH MOISTURE WILL BE ABLE TO SURGE N INTO OUR AREA IS ALSO
IN QUESTION. THE SLOWER ECMWF GIVES MORE TIME FOR MOISTURE TO POOL
TO OUR S...AND MOVE OVERHEAD THURSDAY NIGHT. THE RESULT IS LOWER
THAN AVERAGE CONFIDENCE IN THE ONGOING FCST FROM FRIDAY ON.
A MORE ROBUST SYSTEM SHOULD SET UP OVER THE W HALF OF THE NATION
SATURDAY...IN THE FORM OF A SIGNIFICANT 500MB TROUGH. EXACTLY WHERE
THE SFC LOW SETS UP IS STILL A CONCERN AS THE 00Z RUN OF THE ECMWF
TIES IT TO THE SLOWER LOW IMPACTING OUR WEATHER THURSDAY INTO EARLY
FRIDAY. THE 12Z ECMWF SETS UP THE SECONDARY LOW WELL TO THE S. THE
GFS ON THE OTHER HAND HAS A STRONGER SFC LOW OVER THE CENTRAL PLAINS
AT 00Z SATURDAY MOVING ACROSS OUR AREA SATURDAY NIGHT. THE RESULT IS
MUCH MORE QPF OFF THE GFS...WHILE THE ECMWF PUSHES THE SWATH OF
HIGHEST PRECIP OVER LOWER MI SATURDAY NIGHT. EITHER WAY...COLD AIR
LOOKS POISED TO SLIDE IN FOR THE END OF THE WEEKEND WITH 850MB TEMPS
OF -5 TO -12C BY 00Z MONDAY ON W TO NNW WINDS. RIGHT NOW IT LOOKS
LIKE WE WILL AT LEAST TEMPORARILY BREAK OUR TREND OF ABOVE NORMAL
TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 639 PM EST SUN DEC 6 2015
LOW LEVEL MOISTURE LINGERING OVER KCMX EARLY THIS EVENING KEEPING
CIGS IFR THERE FOR A TIME...BUT LATEST SATELLITE TRENDS SHOW THIS
AREA OF ST GRADUALLY DECREASING. TIMING FOR RETURN TO VFR EXPECTED
TO BE WITHIN THE NEXT HOUR OR TWO PER SATELLITE TRENDS. MORE ST/FG
TO THE SW OF THE AREA...WHICH WILL GRADUALLY MOVE NE THIS
EVENING...COMBINED WITH DECENT RADIATIONAL COOLING UNDER WEAK SFC
RIDGE WILL BRING RESTRICTIONS TO VSBY AT KSAW...WITH LESS
PROBABILITY FOR THIS AT KIWD. IFR VSBYS POSSIBLE AT KSAW DESPITE
WEAK DOWNSLOPE FLOW THERE ALONG WITH SLOW DRYING ASSOCIATED WITH THE
AFOREMENTIONED RIDGE. ONCE THE LOWS CLOUDS/FOG LIFT AT KSAW IN THE
AM...VFR CONDITIONS TO PREVAIL THROUGH THE FORECAST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 405 PM EST SUN DEC 6 2015
THE PRES GRADIENT WILL INCREASE MON NIGHT WITH THE RIDGE SLIDING TO
THE EAST AND LOW PRES MOVING INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25 KNOT WINDS. ANOTHER PERIOD OF SRLY 25 KNOT WINDS IS
EXPECTED THU AHEAD OF LOW PRES MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...RJT
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
323 PM EST SAT DEC 5 2015
.DISCUSSION...
SIGNIFICANT RIDGING ALOFT HAS SUPPORTED A VERY WARM LOWER AND MID
TROPOSPHERIC COLUMN ACROSS THE UPPER MIDWEST AND GREAT LAKES
REGIONS. THE CONSEQUENCE OF THIS MASS CONFIGURATION IS THE
PRODUCTION OF A VERY SHALLOW COOL LAYER AT THE SURFACE THAT CANNOT
MIX WITH THE SLIGHTLY ELEVATED WARM LATER DUE TO THE EXTREMELY
STABLE TRANSITION LAYER. THE MOISTURE CONTENT BELOW THIS STRONG
INVERSION IS REMAINING FAIRLY CONSTANT...SO IT SIMPLY GOES THROUGH A
CONDENSATION CYCLE DURING THE NOCTURNAL HOURS AND EVAPORATION DURING
THE DIURNAL WINDOW. GIVEN THE RATHER STEADY-STATE SURFACE RIDGING
AND LACK OF AIRMASS REPLACEMENT NEAR THE GROUND...THIS CYCLE WILL
CONTINUE CERTAINLY THROUGH TONIGHT AND INDICATIONS ARE AN ADDITIONAL
TWO MORE DAYS BEFORE MORE ROBUST SOUTHWESTERLY FLOW BECOMES
ESTABLISHED ON TUESDAY.
THE VERY SHALLOW NATURE OF THE COOL LAYER /SEE 12Z KDTX RAOB/ ALLOWS
FOR GREATER TRAPPING OF MOISTURE IN THE LOWER ELEVATION REGIONS OF
METRO DETROIT. HENCE...THAT AREA IS THE LAST TO SCOUR OUT THE FOG
AND LOW CLOUDS. THERE IS STILL AN OPPORTUNITY TO CATCH A GLIMPSE OF
THE SUN PRIOR TO SUNSET...BUT IT WILL NOT BE LONG LIVED. EXPECT FOG
FORMATION TO QUICKLY RESUME AFTER SUNSET AND QUICKLY FILL ACROSS
SOUTHEAST MICHIGAN ONCE AGAIN. HRRR AND HRRRX GUIDANCE HAS BEEN
RATHER SKILLFUL WITH TODAY/S EPISODE AND OFFER REASONABLE DEPICTIONS
FOR THE NOCTURNAL CYCLE ONCE AGAIN TONIGHT - THOUGH MAY BE A LITTLE
TOO PESSIMISTIC EARLY IN THE PROCESS. HOWEVER...THESE SITUATIONS ARE
ALL OR NOTHING ONCE DEVELOPMENT COMMENCES. DENSE FOG IS HIGHLY
LIKELY AGAIN TONIGHT...BUT THE TIMING OF ONSET IS IN QUESTION GIVEN
THE LINGERING LOW CLOUDS ACROSS METRO DETROIT AND SOME DEGREE OF
DEWPOINT SEPARATION IN THOSE LOCATIONS WHERE THE SUN HAS BEEN MORE
ACTIVE.
EQUALLY CHALLENGING WILL BE THE SPATIAL QUALITY OF THE FOG / STRATUS
FIELD. EXPECT THE GLACIAL RIDGE TO EXPERIENCE THE LEAST INFLUENCE
ONCE AGAIN AS ELEVATION INTO THE INVERSION LAYER WILL DIMINISH THE
MOISTURE QUALITY AND FOG PRODUCTION EFFICIENCY. WHILE THE LOWER
ELEVATIONS TO THE SOUTH SHOULD HAVE A SIMILAR OUTCOME AS
WITNESSED TODAY.
THE CLOUDS AND FOG WILL SLOWLY GIVE WAY TO SUN PRIOR TO MIDDAY ON
SUNDAY...WITH THE RIDGE LOCATIONS STARTING MUCH EARLIER. THE DELAYED
START TO INSOLATION WILL ONCE AGAIN KEEP TEMPS BELOW STATISTICAL
GUIDANCE...AND IF CLOUDS REFUSE TO BREAK...MUCH BELOW AS
DEMONSTRATED TODAY.
SURFACE HIGH PRESSURE WILL REMAIN OVER THE GREAT LAKES REGION ON
TUESDAY KEEPING SOUTHEAST MICHIGAN DRY. THIS HIGH WILL SLOWLY DRIFT
TOWARDS THE ATLANTIC COAST ON WEDNESDAY AS A SHORTWAVE TROUGH PIVOTS
THROUGH THE GREAT LAKES RESULTING IN A CHANCE OF RAIN SHOWERS ON
WEDNESDAY. WEAK SURFACE RIDGING WILL KEEP US DRY FOR WEDNESDAY NIGHT
HOWEVER A STRONGER LOW PRESSURE SYSTEM QUICKLY FOLLOWS ON THURSDAY.
BEST CHANCE OF PRECIP WITH THE LOW WILL BE ACROSS THE NORTHERN CWA.
A COLD FRONT TRACKS ACROSS THE SOUTHERN GREAT LAKES ON THURSDAY
NIGHT AND INTO FRIDAY BRINGING A BETTER CHANCE OF RAIN TO THE ENTIRE
CWA. A MORE ORGANIZED SURFACE LOW PRESSURE SYSTEM IS FORECASTED TO
IMPACT THE AREA NEXT WEEKEND...HOWEVER...MODEL TENDENCIES ARE
INCONSISTENT IN TIMING OF THIS SYSTEM AT THIS TIME. HAVE LEFT JUST
CHANCE POPS /30 TO 40 PERCENT/ IN THE FORECAST FOR NOW.
&&
.MARINE...
HIGH PRESSURE OVER THE OHIO VALLEY REGION WILL PERSIST THROUGH
THE WEEKEND KEEPING LIGHT SOUTHWESTERLY WINDS ACROSS HURON.
BY MID WEEK A STRONGER FRONT WILL APPROACH FROM THE WEST WITH
INCREASING SPEEDS. HOWEVER WITH UNSEASONABLY MILD AIR IN
PLACE...BOUNDARY LAYER MIXING WILL BE MINIMAL AND WINDS SHOULD
HAVE NO TROUBLE REMAINING SUB-GALE. FOR THE LONGER TERM, THE NEXT
MAJOR FRONTAL SYSTEM IS POSSIBLE NEXT WEEKEND AND COULD BRING
BRIEF GALES TO THE REGION.
&&
.AVIATION...ISSUED 1206 PM EST SAT DEC 5 2015
ADVECTIVE FOG EVENT FROM LAST NIGHT LED TO AN AVIATION MESS
THIS MORNING. MOISTURE IS PRETTY SHALLOW BUT SOLIDLY LOCKED IN DUE
TO TREMENDOUS INVERSION WITH BASE AT ABOUT 300 FEET AGL. LOWER
ELEVATION AREAS SOUTH OF THE GLACIAL RIDGE ARE EXPERIENCING SLIGHT
UPSLOPE SURFACE FLOW THAT IS REINFORCING A BAD SITUATION. IT IS
ENTIRELY LIKELY THAT LOW CIGS ARE GOING TO PERSIST RIGHT THROUGH
THE NIGHT AS RAP SOUNDINGS KEEP STRONG INVERSION IN PLACE. FROM A
VBSY PERSPECTIVE WILL LIKELY SEE A SLIGHT DIURNAL RECOVERY FROM
LIFR TO IFR FOR THE LATTER HALF OF THE AFTERNOON... BUT LATEST HRRR
RUNS STRONGLY SUGGEST SOCKING BACK IN SHORTLY AFTER SUNSET. NORTH OF
THE RIDGE... THINGS ARE QUICKLY IMPROVING LATE THIS MORNING AT PTK..
FNT.. AND MBS. THESE LOCATIONS SHOULD ALL BE VFR AROUND 18-19Z.
AGAIN THOUGH... HRRR RUNS ARE HINTING AT AN ADVECTIVE PUSH
NORTHWARD OF LOW CIGS AND FOG THIS EVENING SO BROUGHT LIFR
CONDITIONS IN AGAIN BY 01-04Z.
FOR DTW...TRENDS AND MODELS ARE INCREASING CONFIDENCE THAT
PROLONGED PERIOD OF LIFR/IFR VSBY WILL IMPACT METRO THROUGH THE NEXT
20 OR SO HOURS. STEEP PERSISTENT LOW LEVEL INVERSION... WEAK
UPSLOPE... AND LOW DECEMBER SUN ANGLE ALL CONSPIRING TO LOCK IN POOR
CONDITIONS. AGAIN... SLIGHT DIURNAL TRENDS COULD IMPROVE VSBY TO 1-3
NILES FOR A FEW HOURS THIS AFTERNOON BEFORE LOWERING AGAIN WITH
SUNSET.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THROUGH SUNDAY
MORNING.
* HIGH CONFIDENCE IN CIGS AT OR BELOW 200 FT THROUGH 20Z TODAY AND
AGAIN FROM 00Z TO 16Z SUNDAY.
* MODERATE TO HIGH CONFIDENCE IN VSBY 1/2 MILES OR LESS THROUGH 20Z
TODAY AND AGAIN FROM 00Z TO 16Z SUNDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
DISCUSSION....MANN/RK
MARINE.......05
AVIATION.....05
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1216 PM EST SAT DEC 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
WILL BE DROPPING THE DENSE FOG ADVISORY AS VISIBILITIES HAVE
IMPROVED LATE THIS MORNING. ALL REPORTING STATIONS ACROSS THE GRR
FORECAST AREA NOW HAVE AT LEAST A 1/2 MILE VISIBILITY. A
SIGNIFICANT IMPROVEMENT FROM EARLIER WHERE VISIBILITY WAS BETWEEN
ZERO AND A 1/4 MILE IN MANY AREAS.
THIS AFTERNOON...THE VERY SHALLOW STRATUS SHOULD ERODE AND SKIES
SHOULD TURN MOSTLY SUNNY AS WE WORK THROUGH THE AFTERNOON. HIGH
TEMPERATURES WILL TOP OUT IN THE MIDDLE TO UPPER 40S.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIED THAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1206 PM EST SAT DEC 5 2015
FOG WILL CONTINUE TO DISSIPATE LEADING TO MOSTLY VFR CONDITIONS BY
MID AFTERNOON. ANOTHER ROUND OF IMPACTFUL CONDITIONS IS LIKELY
FOR LATER TONIGHT. THERE ARE SOME INDICATIONS THAT THE FOG MAY NOT
BE AS WIDESPREAD OVERNIGHT INTO SUNDAY MORNING. THE PATTERN
HOWEVER HAS BEEN SUPPORTIVE OF FOG EACH NIGHT AND WILL CONTINUE TO
REFLECT THIS IN THE LASTEST FORECAST. CURRENT INDICATIONS ARE THAT
THE FOG WILL REDEVELOP AROUND KAZO AND KBTL BEFORE MIDNIGHT THEN
SPREAD/DEVELOP NORTH AND EAST AS THE NIGHT PROGRESSES.
&&
.MARINE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
THE LATEST WAVE MODEL RUN INCORPORATING RUC WIND DATA THROUGH 18
HOURS IS INDICATING SOLID SMALL CRAFT ADVISORY CRITERIA WAVES
NORTH OF WHITEHALL THIS AFTERNOON AND TONIGHT. HAVE OPTED TO GO
AHEAD AND ISSUE A SCA NORTH OF WHITEHALL THROUGH 18Z ON SUNDAY.
THE WINDS SHOULD SUBSIDE CONSIDERABLY THROUGH THE COURSE OF THE
THE DAY ON SUNDAY AND THE WAVES WOULD DO IN KIND.
THE BIG SABLE POINT OBSERVATION SITE IS SHOWING WINDS GUSTING IN
EXCESS OF 18 KNOTS...WHICH IS A VALUE THAT OFTEN PRODUCES SCA
CRITERIA WAVES.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR LMZ848-849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...MJS
HYDROLOGY...CAS
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1206 PM EST SAT DEC 5 2015
.AVIATION...
ADVECTIVE FOG EVENT FROM LAST NIGHT LED TO AN AVIATION MESS
THIS MORNING. MOISTURE IS PRETTY SHALLOW BUT SOLIDLY LOCKED IN DUE
TO TREMENDOUS INVERSION WITH BASE AT ABOUT 300 FEET AGL. LOWER
ELEVATION AREAS SOUTH OF THE GLACIAL RIDGE ARE EXPERIENCING SLIGHT
UPSLOPE SURFACE FLOW THAT IS REINFORCING A BAD SITUATION. IT IS
ENTIRELY LIKELY THAT LOW CIGS ARE GOING TO PERSIST RIGHT THROUGH
THE NIGHT AS RAP SOUNDINGS KEEP STRONG INVERSION IN PLACE. FROM A
VBSY PERSPECTIVE WILL LIKELY SEE A SLIGHT DIURNAL RECOVERY FROM
LIFR TO IFR FOR THE LATTER HALF OF THE AFTERNOON... BUT LATEST HRRR
RUNS STRONGLY SUGGEST SOCKING BACK IN SHORTLY AFTER SUNSET. NORTH OF
THE RIDGE... THINGS ARE QUICKLY IMPROVING LATE THIS MORNING AT PTK..
FNT.. AND MBS. THESE LOCATIONS SHOULD ALL BE VFR AROUND 18-19Z.
AGAIN THOUGH... HRRR RUNS ARE HINTING AT AN ADVECTIVE PUSH
NORTHWARD OF LOW CIGS AND FOG THIS EVENING SO BROUGHT LIFR
CONDITIONS IN AGAIN BY 01-04Z.
FOR DTW...TRENDS AND MODELS ARE INCREASING CONFIDENCE THAT
PROLONGED PERIOD OF LIFR/IFR VSBY WILL IMPACT METRO THROUGH THE NEXT
20 OR SO HOURS. STEEP PERSISTENT LOW LEVEL INVERSION... WEAK
UPSLOPE... AND LOW DECEMBER SUN ANGLE ALL CONSPIRING TO LOCK IN POOR
CONDITIONS. AGAIN... SLIGHT DIURNAL TRENDS COULD IMPROVE VSBY TO 1-3
NILES FOR A FEW HOURS THIS AFTERNOON BEFORE LOWERING AGAIN WITH
SUNSET.
//DTW THRESHOLD PROBABILITIES...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THROUGH SUNDAY
MORNING.
* HIGH CONFIDENCE IN CIGS AT OR BELOW 200 FT THROUGH 20Z TODAY AND
AGAIN FROM 00Z TO 16Z SUNDAY.
* MODERATE TO HIGH CONFIDENCE IN VSBY 1/2 MILES OR LESS THROUGH 20Z
TODAY AND AGAIN FROM 00Z TO 16Z SUNDAY.
&&
.PREV DISCUSSION...ISSUED 547 AM EST SAT DEC 5 2015
UPDATE...
WILL UPDATE TO CANCEL THE DENSE FOG ADVISORY OVER THE SAGINAW
VALLEY WHERE 5 TO 10 MPH SOUTHWEST GRADIENT FLOW IS HELPING TO
MITIGATE THE FORMATION OF DENSE FOG AS VISIBILITIES ARE HOLDING
MORE IN THE 2 TO 5 MILE RANGE.
ELSEWHERE...DENSE FOG CONTINUES TO SLOWLY EXPAND ACROSS THE REGION
AND EXPECT THIS TREND TO CONTINUE UNTIL BETWEEN 8 AND 9 AM. IT
WILL THEN TAKE MOST OF THE MORNING FOR THIS FOG TO BURN OFF. IN
FACT...PARTLY TO MOSTLY CLEAR SKIES WILL MOST LIKELY HOLD OFF
UNTIL MID AFTERNOON IN SOME LOCATIONS. FOR THIS REASON...WILL ALSO
LOWER HIGH TEMPERATURES A BIT MORE WITH HIGHS IN THE LOWER TO MID
40S EXPECTED.
PREV DISCUSSION...ISSUED 335 AM EST SAT DEC 5 2015
DISCUSSION...
LARGE AREA OF STRATUS CONTINUES TO BUILD EAST AND NORTHEAST OVER
AREA EARLY THIS MORNING AND EXPECT THIS TREND TO PERSIST THROUGH
SUNRISE OR A BIT LATER...LEADING TO GENERALLY CLOUDY SKIES ACROSS
THE ENTIRE FORECAST AREA BY DAYBREAK. THIS MOISTURE IS TRAPPED UNDER
A VERY SHALLOW LOW LEVEL INVERSION WITH CEILINGS ON THE ORDER OF 100
TO 200 FEET. THIS MOISTURE EXTENDS TO THE BOUNDARY LAYER SO ALSO
EXPECT THE AREAS OF DENSE FOG NOTED WITHIN STRATUS FIELD TO EXPAND
ACROSS AREA. THIS WILL REQUIRE A DENSE FOG ADVISORY FOR ALL OR MOST
OF SOUTHEAST LOWER MICHIGAN AS VISIBILITY AT OR BELOW ON QUARTER OF
A MILE WILL BECOME MORE WIDESPREAD DURING THE REMAINDER OF THE
OVERNIGHT AND EARLY MORNING HOURS.
WITH A WEAK LOW LEVEL FLOW...EXPECT IT WILL TAKE A WHILE FOR THIS
MOISTURE TO MIX OUT...SO MOSTLY CLOUDY SKIES THIS MORNING WILL
GRUDGINGLY BECOME PARTLY CLOUDY DURING THE AFTERNOON. THIS WILL
LIMIT OVERALL HEATING...AND WILL LOWER MAXIMUM TEMPERATURES SEVERAL
DEGREES TODAY...WITH HIGHS TENTATIVELY EXPECTED TO REACH THE MIDDLE
40S BY MID/LATE AFTERNOON.
HEADING THROUGH LATE THIS WEEKEND ON THROUGH THE UPCOMING WEEK...IT
APPEARS A RATHER MILD PERIOD OF WEATHER IS SETTING UP OVER THE GREAT
LAKES. JET STREAM ENERGY OVER THE PACIFIC OCEAN WILL EXPAND EASTWARD
OVER THE CONUS AND ACT TO TRAP COLDER CANADIAN AIR WELL NORTH OF THE
CONUS/CANADIAN BORDER...BASICALLY FOR THE BALANCE OF THIS FORECAST
PERIOD.
WITH TIME...THE MILD AIRMASS MOVING OVER THE CONUS FROM THE
PACIFIC WILL COMBINED WITH INCREASED SOUTH/SOUTHWEST FLOW FROM THE
GULF STATES TO BRING A PERIOD OF WELL ABOVE AVERAGE TEMPERATURES.
ABOUT THE ONLY FACTOR NEGATING FROM THIS TREND WILL BE EXTENSIVE
CLOUD COVER AT TIMES...BUT GIVEN THE OVERALL WARMTH OF THE AIRMASS
THAT WILL BE IN PLACE...FEEL CONFIDENT THAT TEMPERATURES WILL
AVERAGE NEARLY 10F ABOVE AVERAGE FOR A GOOD PART OF THE UPCOMING
WEEK WITH MODERATING TEMPERATURES ON INTO NEXT WEEKEND AS UPPER
RIDGING EXPANDS OVER THE EASTERN CONUS IN RESPONSE TO AN AMPLIFYING
UPPER TROUGH OUT WEST AS THE STEADY STREAM OF PACIFIC JET ENERGY
ACTS TO BUCKLE THE UPPER LEVEL FLOW.
IN GENERAL TERMS...THIS SUGGESTS WIDESPREAD TEMPERATURES IN THE 40S
EARLY IN THE WEEK MODERATE FURTHER INTO THE 50S AT TIMES BY LATE IN
THE FORECAST PERIOD. WHILE NO STRONG STORM SYSTEM IS NOTED AT THIS
TIME...SHOWERS WILL BECOME INCREASINGLY LIKELY AS THIS MILD AND
MOIST AIRMASS STEADILY EXPANDS INTO THE AREA...AND BITS OF SHORTWAVE
ENERGY BEGIN TO EJECT INTO AREA FROM DEEPENING UPPER TROUGH TO THE
WEST.
MARINE...
STRONG HIGH PRESSURE OVER THE UPPER OHIO VALLEY AND MID ATLANTIC
WILL SUSTAIN SOUTHWEST WINDS ACROSS THE LAKES TODAY INTO SUNDAY.
VERY WARM AIR ATOP THE LAKE SURFACE WILL HINDER MIXING...SO WINDS
SHOULD REMAIN MAINLY IN THE 10 TO 15 KNOT RANGE WITH GUSTS HOLDING
BELOW 20 KNOTS. THE GRADIENT WILL RELAX OVER THE REGION BY
MONDAY...LEADING TO LIGHT WINDS TO START THE WEEK. THE RELATIVE WARM
LAKE TEMPERATURES SHOULD KEEP FOG AT BAY...ALTHOUGH SOME OF THE
PORTS MAY BE IMPACTED BY SOME FOG THIS MORNING AND SUNDAY MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....05
UPDATE.......DG
DISCUSSION....DG
MARINE.......SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1155 AM EST SAT DEC 5 2015
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
WILL BE DROPPING THE DENSE FOG ADVISORY AS VISIBILITIES HAVE
IMPROVED LATE THIS MORNING. ALL REPORTING STATIONS ACROSS THE GRR
FORECAST AREA NOW HAVE AT LEAST A 1/2 MILE VISIBILITY. A
SIGNIFICANT IMPROVEMENT FROM EARLIER WHERE VISIBILITY WAS BETWEEN
ZERO AND A 1/4 MILE IN MANY AREAS.
THIS AFTERNOON...THE VERY SHALLOW STRATUS SHOULD ERODE AND SKIES
SHOULD TURN MOSTLY SUNNY AS WE WORK THROUGH THE AFTERNOON. HIGH
TEMPERATURES WILL TOP OUT IN THE MIDDLE TO UPPER 40S.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIED THAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM EST SAT DEC 5 2015
THE BIG QUESTION FOR TODAY IS WILL THE FOG REALLY BREAK UP TODAY?
THE LATEST RUN OF THE RAP MODEL (11Z) SHOWS THE FOG BREAKING UP AT
GRR..BTL AND LAN BY 19Z OR SO BUT HOLDING IN AT JXN AND AZO. GIVEN
WE HAVE SOUTH WINDS AT THE SURFACE AND THE FOG GOES SOUTH INTO
NORTHERN KENTUCKY AND THAT THIS IS DECEMBER...THIS FOG MAY WELL
LAST INTO THIS AFTERNOON. I WENT WITH THE IDEA THE FOG WOULD BREAK
UP AT ALL TAF SITES BY EARLY AFTERNOON BUT I WILL ADMIT THAT WAS
AN OPTIMIST FORECAST.
THERE IS AN ISSUE WITH THE FOG COMING BACK TONIGHT. THE LATEST RUN
OF THEN NAM SHOWS 20 TO 25 KNOT WINDS IN THE BOUNDARY LAYER
BETWEEN 03Z AND 09Z BUT THOSE WINDS LET UP AFTER 09Z. IT MAY WELL
BE THAT IS A BIG ENOUGH WINDOW...GIVEN IT IS DECEMBER TO THAT
DENSE FOG TO COME BACK. SO I DID BRING DENSE FOG IN TOWARD SUNDAY
MORNING.
&&
.MARINE...
ISSUED AT 1155 AM EST SAT DEC 5 2015
THE LATEST WAVE MODEL RUN INCORPORATING RUC WIND DATA THROUGH 18
HOURS IS INDICATING SOLID SMALL CRAFT ADVISORY CRITERIA WAVES
NORTH OF WHITEHALL THIS AFTERNOON AND TONIGHT. HAVE OPTED TO GO
AHEAD AND ISSUE A SCA NORTH OF WHITEHALL THROUGH 18Z ON SUNDAY.
THE WINDS SHOULD SUBSIDE CONSIDERABLY THROUGH THE COURSE OF THE
THE DAY ON SUNDAY AND THE WAVES WOULD DO IN KIND.
THE BIG SABLE POINT OBSERVATION SITE IS SHOWING WINDS GUSTING IN
EXCESS OF 18 KNOTS...WHICH IS A VALUE THAT OFTEN PRODUCES SCA
CRITERIA WAVES.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 1 PM EST SUNDAY FOR LMZ848-849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
947 AM EST SAT DEC 5 2015
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 946 AM EST SAT DEC 5 2015
EXTENDING THE DENSE FOG ADVISORY ACROSS THE SOUTHERN THREE ROWS OF
COUNTIES UNTIL 100 PM...OR ROUGHLY FROM GRAND HAVEN TO GRAND
RAPIDS TO ST. JOHNS SOUTHWARD. WILL BE CANCELLING THE DENSE FOG
ADVISORY ACROSS THE NORTHERN THREE TIERS OF COUNTIES...OR ACROSS
CENTRAL LOWER MI.
DENSE FOG IS STILL WIDESPREAD ACROSS THE SOUTH...WITH MANY SITES
REPORTING A QUARTER MILE VISIBILITY. NOT CONVINCED IT IS GOING TO
RAPIDLY ERODE IN THE NEXT HOUR OR SO...SO FELT IT WAS NECESSARY TO
EXTEND IT THROUGH 100 PM. ONCE THE FOG ERODES AND VISIBILITY
IMPROVES WE WILL CANCEL THE ADVISORY WHICH SHOULD BE SOME TIME
BETWEEN 1100 AM AND 100 PM.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIED THAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM EST SAT DEC 5 2015
THE BIG QUESTION FOR TODAY IS WILL THE FOG REALLY BREAK UP TODAY?
THE LATEST RUN OF THE RAP MODEL (11Z) SHOWS THE FOG BREAKING UP AT
GRR..BTL AND LAN BY 19Z OR SO BUT HOLDING IN AT JXN AND AZO. GIVEN
WE HAVE SOUTH WINDS AT THE SURFACE AND THE FOG GOES SOUTH INTO
NORTHERN KENTUCKY AND THAT THIS IS DECEMBER...THIS FOG MAY WELL
LAST INTO THIS AFTERNOON. I WENT WITH THE IDEA THE FOG WOULD BREAK
UP AT ALL TAF SITES BY EARLY AFTERNOON BUT I WILL ADMIT THAT WAS
AN OPTIMIST FORECAST.
THERE IS AN ISSUE WITH THE FOG COMING BACK TONIGHT. THE LATEST RUN
OF THEN NAM SHOWS 20 TO 25 KNOT WINDS IN THE BOUNDARY LAYER
BETWEEN 03Z AND 09Z BUT THOSE WINDS LET UP AFTER 09Z. IT MAY WELL
BE THAT IS A BIG ENOUGH WINDOW...GIVEN IT IS DECEMBER TO THAT
DENSE FOG TO COME BACK. SO I DID BRING DENSE FOG IN TOWARD SUNDAY
MORNING.
&&
.MARINE...
ISSUED AT 320 AM EST SAT DEC 5 2015
SOUTHERLY WINDS AROUND 5 TO 15 KTS WILL PRODUCE WAVE HEIGHTS
RANGING FROM 1 TO AS HIGH AS 4 FEET TODAY... HIGHEST UP AROUND BIG
AND LITTLE SABLE POINTS. WAVE HEIGHTS COULD BRIEFLY FLIRT WITH
SMALL CRAFT CRITERIA LATE THIS AFTERNOON AND TONIGHT NORTH OF
WHITEHALL BUT IT IS TOO MARGINAL FOR A SMALL CRAFT ADVISORY AT
THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FREEZING FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ056>059-064>067-071>074.
LM...NONE.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
709 AM EST SAT DEC 5 2015
LATEST UPDATE...
UPDATE/AVIATION
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.UPDATE...
ISSUED AT 710 AM EST SAT DEC 5 2015
AS FORECAST BY THE HRRR RAP AND NAM MODELS THE FOG CONTINUES TO
SPREAD NORTHWARD. THERE WAS A BRIEF THINNING OF THE FOG OVER THE
GRAND RAPIDS TO NEAR KALAMAZOO AREA BUT THE THOSE SAME MODELS
HANDLED THAT NICELY TOO. IN FACT THE RAP MODEL SHOWED THE FOG
THINNING WHERE IT THINNED ONLY TO THICKEN TOWARD MORNING. THIS WAS
RELATED TO THE MORE WESTERLY WINDS EARLY THIS MORNING BRINGING IN
WARMER AIR BUT AS WINDS TURNED MORE TO THE SOUTH OVER THE PAST 2
HOURS THAT BROUGHT THE BELOW FREEZING AIR NORTHWARD AND THICKENED
THE FOG ONCE AGAIN. GIVEN THIS IS DECEMBER AND THAT THE FOG
EXTENDS SOUTH TO NEAR THE OHIO RIVER...IT WOULD SEEM IT WILL BE
AWHILE TILL IT BURNS OFF. THE HIGH RESOLUTION MODELS MIX OUT THE
FOG BETWEEN 11 AM AND 2 PM.
WE WILL HAVE TO WATCH FOG OVERNIGHT... THE LATEST RUN OF THE NAM
SHOWS WINDS DIMINISHING AFTER 04 AM...THAT WOULD ALLOW THE FOG TO
REFORM AGAIN.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIEDTHAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 710 AM EST SAT DEC 5 2015
THE BIG QUESTION FOR TODAY IS WILL THE FOG REALLY BREAK UP TODAY?
THE LATEST RUN OF THE RAP MODEL (11Z) SHOWS THE FOG BREAKING UP AT
GRR..BTL AND LAN BY 19Z OR SO BUT HOLDING IN AT JXN AND AZO. GIVEN
WE HAVE SOUTH WINDS AT THE SURFACE AND THE FOG GOES SOUTH INTO
NORTHERN KENTUCKY AND THAT THIS IS DECEMBER...THIS FOG MAY WELL
LAST INTO THIS AFTERNOON. I WENT WITH THE IDEA THE FOG WOULD BREAK
UP AT ALL TAF SITES BY EARLY AFTERNOON BUT I WILL ADMIT THAT WAS
AN OPTIMIST FORECAST.
THERE IS AN ISSUE WITH THE FOG COMING BACK TONIGHT. THE LATEST RUN
OF THEN NAM SHOWS 20 TO 25 KNOT WINDS IN THE BOUNDARY LAYER
BETWEEN 03Z AND 09Z BUT THOSE WINDS LET UP AFTER 09Z. IT MAY WELL
BE THAT IS A BIG ENOUGH WINDOW...GIVEN IT IS DECEMBER TO THAT
DENSE FOG TO COME BACK. SO I DID BRING DENSE FOG IN TOWARD SUNDAY
MORNING.
&&
.MARINE...
ISSUED AT 320 AM EST SAT DEC 5 2015
SOUTHERLY WINDS AROUND 5 TO 15 KTS WILL PRODUCE WAVE HEIGHTS
RANGING FROM 1 TO AS HIGH AS 4 FEET TODAY... HIGHEST UP AROUND BIG
AND LITTLE SABLE POINTS. WAVE HEIGHTS COULD BRIEFLY FLIRT WITH
SMALL CRAFT CRITERIA LATE THIS AFTERNOON AND TONIGHT NORTH OF
WHITEHALL BUT IT IS TOO MARGINAL FOR A SMALL CRAFT ADVISORY AT
THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ037>040-043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
406 AM EST SAT DEC 5 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 320 AM EST SAT DEC 5 2015
HIGH PRESSURE WILL PRODUCE FAIR AND MILD WEATHER THROUGH THE
WEEKEND. HOWEVER AREAS OF DENSE FOG THIS MORNING WILL CAUSE
HAZARDOUS TRAVEL CONDITIONS. TEMPERATURES WILL CONTINUE TO AVERAGE
AT LEAST TEN TO FIFTEEN DEGREES ABOVE NORMAL THROUGH THE UPCOMING
WEEK.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
A FREEZING FOG ADVISORY REMAINS IN EFFECT FOR ALL OF OUR FCST AREA
THROUGH 15Z THIS MORNING. SFC OBS/GROUND TRUTH REPORTS CONTINUE TO
INDICATE AREAS OF DENSE FOG ACROSS MUCH OF OUR FCST AREA. THIS IN
CONJUNCTION WITH SFC TEMPS AT OR BELOW FREEZING ACROSS PORTIONS OF
OUR AREA WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS THROUGH MID
MORNING.
FOG WILL GRADUALLY DISSIPATE LATE THIS MORNING AND SKIES ARE
EXPECTED TO BECOME PARTLY TO MOSTLY SUNNY THIS AFTERNOON WITH
SUBSIDENCE UNDER THE HIGH PRESSURE RIDGE. IT WILL BECOME MILD AGAIN
TODAY WITH HIGH TEMPS REACHING THE MIDDLE TO UPPER 40S (00Z MET
NUMERICAL GUIDANCE MAXES ARE MUCH TOO COOL). THE HIGH PRESSURE RIDGE
WILL CONTINUE IN CONTROL OF THE WX PATTERN AND BRING FAIR WEATHER
THROUGH MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 AM EST SAT DEC 5 2015
THE SHORT STORY IS WARMER THAN NORMAL TEMPERATURES WILL BE FOLLOWED
MUCH WARMER THAN NORMAL TEMPERATURES LATER IN THE WEEK. WE WILL
TREND INTO A MUCH WETTER PATTERN AS WE HEAD TOWARD NEXT WEEKEND.
FOR THE MOST PART THE MODELS HAVE BEEN VERY CONSISTENT IN THE LARGE
SCALE DETAIL FOR THIS COMING WEEK. OUR VERY ACTIVE PACIFIC WAVE
TRAIN CONTINUES TO FEED SYSTEMS ON SHORE ABOUT EVERY TWO DAYS. WITH
THE SPLIT FLOW MOST OF THE PRECIPITATION HAS BEEN WELL NORTH IN
CANADA AND THIS COMING WEEK WE WILL SEE A LITTLE RAIN TRACK JUST
SOUTH OF MICHIGAN WITH THE SOUTHERN STREAM EARLY IN THE WEEK.
HOWEVER AS OUR VERY IMPRESSIVE 180 KNOT EAST ASIAN JET CORE (WE
HAVE BEEN FOLLOWING THIS ALL WEEK) GETS CLOSER TO WESTERN NORTH
AMERICA THE WAVES MOVING ON SHORE WILL AMPLIFY. THIS WILL
INCREASE THE FLOW OF GULF MOISTURE NORTH AND ALSO INCREASE JUST
HOW FAR NORTH THAT MOISTURE GETS.
IT SEEMS TO ME THE STORM NOW OFF THE WEST COAST (LOOKS GREAT ON THE
1 AM WATER VAPOR LOOPS...CHECK IT OUT OF YOU CAN) WILL BE OUR
WEDNESDAY SYSTEM. THIS ONE MAY HAVE ENOUGH WAVE LENGTH AS IT MOVES
TROUGH THE CENTRAL PLAINS TO GIVE US A FEW SHOWERS WEDNESDAY.
THERE WILL BE ONE MORE SYSTEM COMING THROUGH BEFORE THE SYSTEM WITH
THAT EAST ASIAN JET CORE OVER 180 KNOTS MOVES ONSHORE. THAT ONE
REACHES US IN THE FRIDAY TIME FRAME. THAT WILL BE MORE AMPLIFIEDTHAN
THE WEDNESDAY SYSTEM SO EXPECT A MORE WIDESPREAD RAIN EVENT WITH
THAT ONE.
MORE THAN LIKELY OUR TEMPERATURE FORECAST IS TO CONSERVATIVE... I
BELIEVE WE COULD SEE ACTUAL TEMPERATURE AS MUCH AS 5 TO 10 DEGREES
WARMER THAN WE ARE FORECASTING BY LATE IN THE PERIOD.
.WEEK TWO FORECAST...(SATURDAY THROUGH FRIDAY)
OF COURSE THE MAIN SHOW COMES THE NEXT WEEKEND INTO THE MIDDLE OF
THE FOLLOWING WEEK. BOTH THE ECMWF AND GFS SHOW THE AO AND NAO TENDING
TOWARD NEGATIVE VALUES THEN AND THE PNA GOING POSITIVE. ALL THAT
WOULD SUGGEST WESTERN RIDGE AND EASTERN TROUGH. THIS GOES WELL
WITH THE PROGRESSION OF THAT EAST ASIAN JET CORE. THE MAIN ENERGY
FOR THIS SYSTEM WILL COME TROUGH THE GREAT LAKES DURING THE
WEEKEND OF THE 12TH (SATURDAY). TIMING MAY BE SLOWER THAN I AM
SAYING BUT THE SYSTEM IN THE TIME FRAME OF SUNDAY THE 13TH COULD
BE A VERY DEEP SURFACE LOW WITH A LOT OF WIND AND A STRONG SURGE
OF EVERY WARM AIR. IT IS THIS SYSTEM THAT I THINK WILL BEING US
RECORD OR NEAR RECORD HIGHS IN THE MID 60S SATURDAY OR SUNDAY.
FOR THOSE WAITING FOR SNOW AND COLD... YOU MAY GET YOUR WISH BY THE
MIDDLE TO END OF THAT WEEK (THINK THE 15TH TO 18TH). THERE IS ONE
MORE SHORTWAVE THAT TRAILS THE MAIN SYSTEM. AS THAT MOVES INTO THE
PLAINS I DO BELIEVE WE WILL BE SEEING MUCH BETTER RIDGING OVER THE
WESTERN PLAINS AND MOUNTAIN STATES. THAT WILL FINALLY BRING IN 850
TEMPERATURES IN THE 15 BELOW RANGE INTO OUR AREA AND UNLIKE THE PAST
MONTH OR SO...THIS COLD PUSH WILL NOT LEAVE SO QUICKLY. THE GFS OUT
TO 16 DAYS HAS BEEN SHOWING THIS RUN AFTER RUN NOW FOR A WEEK. THE
CFSV2 ENSEMBLES SHOW SNOW COVER DOWN TO TENNESSEE BY FRIDAY THE
18TH. THIS HAS BEEN CONSISTENT IN THE CFSV2 FOR OVER A WEEK TOO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 405 AM EST SAT DEC 5 2015
WIDESPREAD DENSE FOG HAD DEVELOPED AT GRR...AZO...BTL...LAN AND
JXN BUT THEN THE FOG MIXED OUT AT GRR. AZO IS BEGINNING TO SEE
VISIBILITIES GO UP TOO. SO...WHY DID THIS HAPPEN AND WILL IT FOG
IN AGAIN? LOOKING AT OUR MESO-ANALYSIS WINDS ARE MOSTLY FROM
SOUTHWEST AND FROM GRR TO THE LAKE SHORE TEMPERATURES INCREASE 38
AT GRR TO 41 NEAR HOLLAND. THIS STREAM WARMER AIR MOVING IN
LOWERS THE RELATIVE HUMIDITY AND MIXED OUT THE FOG.
MEANWHILE...OVER THE AZO TO BTL TO JXN AREA WINDS ARE MORE
SOUTHERLY AND AIR TEMPERATURES ARE MOSTLY NEAR FREEZING. THE DENSE
FOG GOES WELL SOUTH IN TO CENTRAL INDIAN AT 4 AM.
AS FOR WHAT I THINK WILL HAPPEN... THE RAP MODEL AND OUR BUKFIT
FOG TOOK SHOW THE FOG COMING BACK IN BY SUNRISE ONLY TO MIX OUT BY
NOON. SO I UPDATED THE TAFS TO SHOW THIS TREND. ALL TAF SITES
EXCEPT MKG SHOULD HAVE DENSE FOG FROM 13Z TO 15Z.
&&
.MARINE...
ISSUED AT 320 AM EST SAT DEC 5 2015
SOUTHERLY WINDS AROUND 5 TO 15 KTS WILL PRODUCE WAVE HEIGHTS
RANGING FROM 1 TO AS HIGH AS 4 FEET TODAY... HIGHEST UP AROUND BIG
AND LITTLE SABLE POINTS. WAVE HEIGHTS COULD BRIEFLY FLIRT WITH
SMALL CRAFT CRITERIA LATE THIS AFTERNOON AND TONIGHT NORTH OF
WHITEHALL BUT IT IS TOO MARGINAL FOR A SMALL CRAFT ADVISORY AT
THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 1152 AM EST FRI DEC 4 2015
RIVERS ARE WELL WITHIN BANKS AND FALLING. WITH LITTLE
PRECIPITATION EXPECTED UNTIL AT LEAST THE LATTER HALF OF NEXT
WEEK... FLOODING CONCERNS ARE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ037>040-043>046-050>052-056>059-064>067-071>074.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...CAS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1202 AM EST SAT DEC 5 2015
.AVIATION...
VERY LOW STRATUS/FOG HAS BEEN INCHING ITS WAY TOWARD SE MI THIS
EVENING WITHIN LOW LEVEL W-SW FLOW. ONGOING COOLING AND MOISTENING
IN THE BOUNDARY LAYER OVER SE MI SUGGESTS THE LOW CLOUDS AND FOG
WILL OVERSPREAD THE TERMINALS EARLY THIS MORNING. THERE IS A CONCERN
THAT THE DEGREE OF COOLING IN THE BOUNDARY LAYER WILL MAKE
CONDITIONS PRIME FOR SOME DENSE FOG. THIS SUPPORTS LOWERING BOTH
CEILINGS AND VISIBILITIES A LITTLE MORE FROM THE PREVIOUS FORECAST.
THE ONGOING ADVECTION OF VERY WARM AIR ABOVE THE INVERSION /925MB
TEMPS TO +8C/ WILL LEAD TO AN EXTREMELY DEEP LOW LEVEL INVERSION.
THIS WILL MAKE IT VERY DIFFICULT FOR THE LOW DECEMBER SUN ANGLE TO
MIX THIS MOISTURE OUT THIS AFTERNOON. THE HIGHER TERRAIN AROUND PTK
WILL BE DEEPER INTO THE INVERSION...LEADING TO A MORE SHALLOW MOIST
LAYER...LIKELY MAKING THESE LOCALS THE FIRST TO SEE THE MOISTURE MIX
OUT THIS AFTERNOON. GRADUAL EROSION OF THE CLOUDS SHOULD THEN TAKE
HOLD DURING THE COURSE OF THE AFTERNOON.
FOR DTW...EXTRAPOLATION FROM SATELLITE SUGGESTS THE LOW CLOUDS/FOG
ARRIVING AT METRO BETWEEN 08Z AND 09Z. THERE IS A POTENTIAL FOR
BOUNDARY LAYER COOLING TO ACCELERATE THE PACE OF THESE
CLOUDS...SUPPORTING AN 08Z ONSET TIME. THERE IS A CONSIDERABLE
DEGREE OF UNCERTAINTY WITH RESPECT TO TIMING THE DISSIPATION OF THIS
MOISTURE THIS AFTERNOON. THERE IS ACTUALLY A CHANCE THAT THE LOW
CLOUDS/FOG HOLD RIGHT INTO SAT NIGHT CONSIDERING THE LOW SUN ANGLE.
//DTW THRESHOLD PROBABILITIES...
* HIGH IN CEILINGS BELOW 5000 FT THIS MORNING AND AFTERNOON. LOW
THIS EVENING.
* MEDIUM IN CIGS/VSBY FALLING BELOW 200 FT AND/OR 1/2SM THIS
MORNING.
&&
.PREV DISCUSSION...ISSUED 1001 PM EST FRI DEC 4 2015
UPDATE...
REMNANT VERY LOW STRATUS DECK LODGED WITHIN THE BACKGROUND OF WEAK
SURFACE RIDGING NOW ENCOMPASSING MUCH OF INDIANA BEGINNING A MORE
PROGRESSIVE OUTWARD EXPANSION AS NOCTURNAL COOLING STRENGTHENS. 1000-
975 MB RH FIELDS ON BOTH THE HRRR AND RAP CONCUR WITH BOTH THE
CURRENT PLACEMENT OF THIS CLOUD DECK AND THE EVENTUAL NORTHEAST
MOVEMENT TOWARD THE FORECAST AREA OVERNIGHT. THESE TRENDS WOULD
POINT TOWARD TAKING A DECIDELY MORE PESSIMISTIC OUTLOOK ON CLOUD
COVER NEARLY AREAWIDE FOR THE EARLY-MID MORNING PERIOD. ELEMENT OF
SHALLOW FOG WITHIN THIS NEAR SURFACE MOISTURE PLUME AS WELL. COOLING
PROCESS MAKING THE MOST OF THIS LONG DURATION OF OPEN SKY EARLY
TONIGHT...SOME LOCALES ALREADY DOWN INTO THE LOWER 30S. OVERALL LOW
TEMPERATURE FORECAST IN LINE WITH CURRENT TRENDS...SOME REALIGNMENT
OF THE TEMPERATURE CURVE GOING FORWARD BASED ON EXPECTATIONS FOR
CLOUD COVER TO EVENTUALLY CAP THIS COOLING /PARTICULARLY SOUTHWEST
SECTIONS/.
PREV DISCUSSION...ISSUED 318 PM EST FRI DEC 4 2015
DISCUSSION...
THE MAIN WEATHER NARRATIVE REMAINS THE EXTENDED RUN INTO NEXT
WEEKEND...OF ABOVE NORMAL TEMPERATURES...A HIGH AMOUNT OF SUNSHINE
FOR DECEMBER...AND THE PREDOMINATELY DRY CONDITIONS.
DECISIVE CLEARING CAME TO FRUITION THIS MORNING ON THE BACKS OF VERY
ACTIVE SUBSIDENCE IN THE 925-700MB LAYER. THIS FRESH ROUND OF
SUBSIDENCE OCCURRED ALONG THE SOUTHERN PERIPHERY OR IN THE ZONE OF AVA
BEHIND A SHORTWAVE THAT CUT THROUGH THE GREAT LAKES LAST NIGHT. FOR
TONIGHT...MODELED MOISTURE PROFILES MAINTAIN HIGHER AMBIENT MOISTURE
IN THE BOUNDARY LAYER WHICH INTRODUCES SOME UNCERTAINTY. WITH THAT
STATED...OVERALL THERMODYNAMIC STRUCTURE AND STEADY LOWERING OF THE
INVERSION BASE DURING THE NEXT 12 TO 36 HOURS SUGGESTS THAT NOW THAT
CLOUDS HAVE BROKEN IT WILL BE DIFFICULT TO DEVELOP NEW CLOUD.
INSTEAD...THE POTENTIAL DOES EXIST FOR CLOUD TO THE SOUTH TO EXPAND
IN COVERAGE BACK NORTHWARD POSSIBLY IMPACTING AREAS SOUTH OF M 59
LATER TONIGHT. DUE TO THE INVERSION STRUCTURE...FORECASTER
PREFERENCE IS SIDED TO POTENTIAL FOG DEVELOPMENT LATE TONIGHT RATHER
THAN STRATUS. WITH THIS IN MIND THE BETTER POTENTIAL REMAINS ACROSS
THE SOUTHERN CWA AND INTO ST CLAIR COUNTY WHERE THE BOUNDARY LAYER
GRADIENT WINDS WILL BE ALLOWED TO RELAX UNDER BETTER SURFACE HIGH
PRESSURE.
LESS IN THE WAY OF STRATUS/FOG IS EXPECTED TO BEGIN THE DAY SATURDAY
THAN THIS MORNING. THIS WILL SET THE STAGE FOR A WONDERFUL EARLY
DECEMBER SATURDAY ACROSS ALL OF SOUTHEASTERN MICHIGAN. THE BIG
QUESTION FOR SATURDAY IS WHAT WILL HIGH TEMPERATURES BE WITH A VERY
STRONG STABLE LAYER LOWERING AND SQUASHING MIXING HEIGHTS OVER THE
REGION. MODELS HAVE BEEN UNDERFORECASTING HIGHS A TOUCH THE PAST TWO
DAYS...AS A RESULT...INCREASED HIGHS INTO THE LOWER 50S MANY
AREAS...UPPER 40S NEAR THE WATER AND LOWER SURFACE PRESSURE
LOCATIONS. WITH AMOUNT OF GRADIENT FLOW THAT IS NORMALLY IN PLACE
THIS TIME OF YEAR...A PRETTY ATYPICAL FORECAST WITH THE INVERSION ON
THE GROUND. SUFFICE IT TO SAY WITH PARAMETERIZATIONS AND NEGLIGIBLE
VERTICAL RESOLUTION IN THE MODEL DATA...THERE ISN`T A WHOLE LOT OF
CONFIDENCE IN THE MAX TEMPERATURE GUIDANCE.
A SIZABLE MIDLEVEL SHORTWAVE AND PSEUDO CUTOFF IS FORECASTED TO
ARRIVE OVER THE CENTRAL GREAT LAKES BY LATE SUNDAY. WHILE MODELS
HAVE SOUTHEASTERN MICHIGAN ON THE FAVORABLE SIDE FOR MIDLEVEL
FORCING...PRIMARILY DEFORMATION...FORECAST DATA IS OVERWHELMINGLY IN
SUPPORT OF A MOISTURE STARVED SYSTEM. SUSPECT...HIGH CLOUD TO
INCREASE DURING THE DAY ON SUNDAY BUT NOT IN TIME TO CLASSIFY THE
DAY AS CLOUDY OR OVERCAST. HIGHS ON SUNDAY ARE AGAIN EXPECTED TO
REACH THE MIDDLE 40S.
QUIET EXTENDED PERIOD IS IN STORE FOR SOUTHEAST MICHIGAN. SURFACE
HIGH PRESSURE AND UPPER LEVEL RIDGING WILL REMAIN IN PLACE ACROSS
THE MIDWEST RESULTING IN DRY AND PLEASANT CONDITIONS. A SHORTWAVE
TROUGH PIVOTING THROUGH THE GREAT LAKES REGION ON WEDNESDAY NIGHT
WILL BRING THE NEXT CHANCE OF RAIN TO THE REGION. AT THIS TIME HAVE
ONLY INCLUDED A SLIGHT CHANCE /20 PERCENT/ FOR WEDNESDAY NIGHT INTO
THURSDAY. HIGH TEMPERATURES REMAIN IN THE MID TO UPPER 40S FROM
MONDAY THROUGH NEXT THURSDAY. LOW TEMPERATURES DROP INTO THE LOW TO
MID 30S OVERNIGHT.
MARINE...
SLOWLY WARMING SOUTH-SOUTHWEST FLOW PREDOMINATELY IN THE 10 TO 15
KNOT RANGE WILL BE IN PLACE THROUGH THE WEEKEND OVER THE CENTRAL
GREAT LAKES...LEADING TO STABLE PROFILES AND LOW WAVES. A FEW GUSTS
UP AROUND 20 KNOTS ARE EXPECTED ACROSS CENTRAL PORTIONS OF LAKE
HURON. HIGH PRESSURE WILL EXPAND BACK ACROSS THE GREAT LAKES EARLY
NEXT WEEK...PROVIDING LIGHT WINDS MONDAY INTO AT LEAST TUESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......MR
DISCUSSION...CB/RK
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DULUTH MN
944 PM CST SUN DEC 6 2015
.UPDATE...
ISSUED AT 944 PM CST SUN DEC 6 2015
DENSE FOG HAS BEEN FORMING/EXPANDING AND PERSISTING FROM CASS AND
SOUTHERN ITASCA EASTWARD TO SOUTHERN ST. LOUIS...CARLTON AND
PINE COUNTIES. EXPIRATION TIMES ARE BASED ON THE LAST FEW RUNS OF
THE HRRR EXP AND RAP WHICH HAVE BEEN VERY CONSISTENT. REST OF THE
FORECAST IN GOOD SHAPE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 246 PM CST SUN DEC 6 2015
STRATUS AND FOG HAS SLOWLY ERODED FROM THE NORTH AND AND WEST
TODAY. STRATUS REMAINED OVER OUR SOUTHERN WISCONSIN COUNTIES AND
ACROSS PORTIONS OF CROW WING...AITKIN...PINE AND CARLTON COUNTIES
IN MINNESOTA AS OF LATE AFTERNOON. THE DIMINISHING TREND SHOULD
CONTINUE FOR A COUPLE MORE HOURS...THEN IT MAY EXPAND AGAIN AFTER
SUNSET. WEAK HIGH PRESSURE WILL MOVE THROUGH THE AREA TONIGHT WITH
LIGHT WINDS THIS EVENING. FOG SHOULD ALSO FORM THROUGH THE
EVENING. THE GRADIENT WILL TIGHTEN OVERNIGHT...MAINLY OVER WESTERN
AREAS. AS THIS OCCURS OVERNIGHT...THE FOG MAY LIFT AND ANY STRATUS
MAY START TO DISSIPATE AS SOME MIXING WITH THE VERY DRY AIR ALOFT
OCCURS. THIS IS MOST LIKELY OVER THE WESTERN HALF OF THE
NORTHLAND.
A SHORTWAVE WILL MOVE IN ON MONDAY AS THE HIGH DEPARTS. AT THIS
TIME...WE HAVE A DRY FORECAST AS MOISTURE IS LACKING AND THE
FORCING IS NOT VERY STRONG. WE DO EXPECT MOSTLY CLOUDY SKIES
THROUGH THE DAY. IT WILL BE MILD WITH HIGHS IN THE UPPER THIRTIES
TO LOWER FORTIES.
ANOTHER SHORTWAVE WILL IMPACT THE REGION ON TUESDAY AND BRING A
CHANCE FOR PRECIPITATION. AT THIS TIME...IT LOOKS LIKE MAINLY
RAIN WILL FALL DURING THE DAY. HIGHS WILL BE IN THE LOWER FORTIES.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 246 PM CST SUN DEC 6 2015
CONTINUED ABOVE NORMAL TEMPERATURES THROUGH MOST OF THE
EXTENDED. HAVE KEPT SMALL POPS FOR RA/SN MIX TUESDAY NIGHT AS AN
850HPA LOW SWEEPS OVER THE REGION. DEPENDING ON THE TIMING OF THE
WAVE/PRECIPITATION...THERE COULD BE A PERIOD OF LIGHT FREEZING
DRIZZLE/RAIN. HOWEVER...PRECIPITATION AMOUNTS LOOK TO REMAIN LIGHT
WITH THIS FAST MOVING SYSTEM.
LONG RANGE MODELS SHOWING A STRENGTHENING LOW PRESSURE SYSTEM WITH
DEEPENING 500HPA LOW...TRACKS ACROSS THE UPPER MIDWEST/WESTERN
GREAT LAKES REGION WEDNESDAY NIGHT/THURSDAY. LATEST GFS AND EC ARE
IN AGREEMENT STRONG WARM AIR ADVECTION ACCOMPANIES THIS
SYSTEM...BRINGING 850HPA WELL ABOVE 0C INTO THE REGION AHEAD OF THE
LOW AND KEEPING PTYPE ALL RAIN. TEMPERATURE PROFILES RAPIDLY COOL
LATE THURSDAY/THURSDAY NIGHT AS THE SYSTEM RETREATS OVER THE GREAT
LAKES AND WINDS TURN OUT OF THE WEST/NORTHWEST. ALTHOUGH TIMING AND
TRACK OF THE LOW VARIES...BOTH MODELS ARE SHOWING THE BULK OF THE
FORCING/PRECIPITATION IS ASSOCIATED WITH THE DEEPENING 850HPA LOW
ALIGNED WITH A 500HPA VORT MAX...WHICH BRINGS CORRIDOR OF QPF IN
EXCESS OF 0.5 INCH AND THE POTENTIAL FOR A FEW INCHES OF SNOWFALL
ACROSS NORTHERN MINNESOTA.
THERE MAY BE A PERIOD FAVORABLE FOR LAKE EFFECT SNOW ALONG THE SOUTH
SHORE OF LAKE SUPERIOR SUNDAY NIGHT/MONDAY AS AN AREA OF 850HPA
TEMPS IN THE NEGATIVE TEENS SPREADS OVER LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 505 PM CST SUN DEC 6 2015
HIGH PRESSURE NEARBY WILL KEEP THE WIND LIGHT AND VARIABLE. THIS
WILL RESULT IN AREAS OF BR...WITH ISOLD FZFG FROM THE SNOWMELT.
WHERE BR/FZFG FORMS...IFR/LIFR/VLIFR IS POSSIBLE. VFR OTHERWISE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 25 40 29 42 / 0 0 0 20
INL 22 42 28 42 / 0 0 0 30
BRD 24 42 28 43 / 0 0 0 30
HYR 22 43 29 43 / 0 0 10 20
ASX 23 45 32 45 / 0 0 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 8 AM CST MONDAY FOR MNZ034>038.
DENSE FOG ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ025-026-033.
LS...NONE.
&&
$$
UPDATE...GSF
SHORT TERM...MELDE
LONG TERM...GRANING
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
618 PM CST SUN DEC 6 2015
.UPDATED FOR 00Z AVIATION DISCUSSION...
ISSUED AT 611 PM CST SUN DEC 6 2015
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM CST SUN DEC 6 2015
THE MAIN CONCERN IN THE SHORT TERM IS THE THREAT OF WIDESPREAD DENSE
FOG ACROSS MUCH OF THE FA TONIGHT. AT MID AFTERNOON...A SURFACE HIGH
WAS LOCATED NEAR KSTC. A FEW POCKETS OF DENSE FOG REMAINED UNDER
THE RIDGE AXIS AROUND KLJF...KOVL...KULM. CLEARING EXISTS JUST
WEST OF THESE SITES. THE CONCERN IS THAT THE POCKETS OF DENSE FOG
WILL CONGEAL AND BEGIN TO SPREAD NW THIS EVENING AS LIGHT SE WINDS
DEVELOP ON THE BACKSIDE OF THE HIGH. THE WORST CASE SCENARIO
CONTINUES TO BE FROM THE HRRR WITH WIDESPREAD DENSE FOG SPREADING
IN ALL DIRECTIONS THIS EVENING. THIS HAS BEEN A TREND SEEN SINCE
EARLY THIS MORNING. THE 18Z HOPWRF HAS A SIMILAR SOLUTION EXCEPT
IT DIMINISHES THE FOG IN THE WESTERN CWA LATE TONIGHT. THE 12Z ARW
KEEPS THE DENSE FOG MORE CONFINED TO WHERE IT IS THROUGH THE
EVENING AND THEN BEGINS TO DIMINISH IT DURING THE OVERNIGHT HOURS
AS THE SURFACE WIND FIELD BEGINS TO INCREASE FROM THE SE. MODELED
THE FORECAST MORE TOWARDS THE ARW DUE TO THE INCREASE IN WINDS TO
THE WEST ALONG WITH THE FACT THAT EASTERN MN AND WESTERN WI ARE
ALREADY COVERED IN MVFR/IFR CEILINGS WITH LITTLE RADIATIONAL
COMPONENT SEEN AS WELL AS THE ADVECTIVE COMPONENT HAVING COME TO
AN END. THEREFORE...MENTIONED DENSE FOG FOR THE AFOREMENTIONED
AREA OF CENTRAL/SOUTH CENTRAL MN THROUGH THE EVENING WITH
VISIBILITIES PICKING UP OVERNIGHT.
OTHERWISE...DRY WEATHER THROUGH THE SHORT TERM PERIOD. LOWS TONIGHT
ARE FORECAST TO BE IN THE MIDDLE TO UPPER 20S. THE COLDEST READINGS
ARE FROM MILLE LACS ON EASTWARD WHERE SOME CLEARING MAY REACH IN
FROM THE NORTH LATE TONIGHT. THERE IS PLENTY OF POTENTIAL FOR WARM
HIGHS ON MONDAY. HOWEVER...MUCH DEPENDS ON THE CLOUD COVER AND THE
HEIGHT OF THE MIXING. KEEPING THE MIXING TO 950 MB YIELDS HIGHS IN
THE LOWER TO MIDDLE 40S. AN EXCEPTION IS NEAR KCNB WHERE DOWNSLOPE
WINDS MAY YIELD HIGHS AGAIN IN THE LOWER 50S. RAISING THE MIXING
HEIGHT TO 925 MB INCREASES HIGH TEMPERATURES SOME 5 TO 8 DEGREES CWA
WIDE. OPTED TO STAY WITH THE LOWER MIXING HEIGHT DUE TO THE CLOUD
COVER UNCERTAINTY ALONG WITH THE SNOW COVER OVER THE WESTERN THIRD
OF THE FA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM CST SUN DEC 6 2015
STEADY MILD TEMPERATURES WITH A FEW CHANCES FOR LIGHT/QUICK SHOTS
OF PRECIP ARE THE STORY FOR THE UPCOMING WEEK. AT THIS POINT...THE
DOMINATE PRECIP TYPE IS RAIN.
I COUNT 6-8 SHORTWAVES QUICKLY RIPPLING ACROSS THE NORTHERN CONUS
OVER THE NEXT WEEK. MOST OF THESE WILL HAVE NO MAJOR IMPACTS ON
OUR SENSIBLE WEATHER. THE TWO MORE AMPLIFIED WAVES /ON TUES AND
THURS/ WILL LIKELY BRING LIGHT PRECIP TO OR NEAR THE AREA. THE
FIRST SHORTWAVE MOVES THROUGH ON TUESDAY AND WE HAVE INCREASED
POPS TO FROM 0-10% TO 20-40% DURING THE AFTERNOON AND EVENING. THE
LIMITING FACTOR WITH THIS SYSTEM IS THE ABUNDANCE OF MOISTURE AND
A FAIRLY DRY LOWER ATMOSPHERE BELOW 8000-10000FT. THIS SUGGESTS A
LIGHT QPF EVENT WITH SOME CONCERN IN THE OVERALL PRECIP COVERAGE.
THE FORECAST SOUNDINGS DEPICT A RAIN OR RAIN/SLEET MIX EVEN IF WE
MAXIMIZE OUR WET BULB COOLING...IT SIMPLY LOOKS TOO WARM FOR SNOW
AS THE DOMINANT PRECIP TYPE ON TUESDAY. THE SHORTWAVE SWINGS
THROUGH QUICKLY AND THE PRECIP SHOULD SHUT OFF QUICKLY TUESDAY
NIGHT. LIKE MOST COLD FRONTS THE PAST 3 MONTHS...THE COLD
ADVECTION IS WEAK AND THERE WONT BE MUCH OF A TEMPERATURE
REFLECTION.
WEDNESDAY LOOKS QUIET AND MILD AT THIS POINT...BEFORE ANOTHER
SYSTEM MOVES OUT OF THE GULF OF ALASKA...ACROSS THE PACIFIC
NORTHWEST AND INTO THE FORECAST AREA ON THURSDAY. THIS SYSTEM IS
STRONGER THAN THE TUESDAY SYSTEM AND HAS A BROAD SURFACE LOW IN
THE BALLPARK OF 990MB WHEN IT TRANSVERSES CENTRAL/NORTHERN MN. THE
FORECAST AREA REMAINS ON THE WARM SIDE OF THIS SYSTEM AND SOUTH OF
THE HEAVIER PRECIP AXIS AT THIS POINT.
THE STRONG UPPER JET ACROSS THE PACIFIC BREAKS DOWN LATE THIS WEEK
AND THE CONUS ENDS UP WITH A PRONOUNCED LONGWAVE TROUGH OVER THE
WEST COAST THAT HEADS EAST NEXT WEEKEND. AT THIS POINT...A BAND
OF HEAVY PRECIP WILL LIKELY ACCOMPANY THIS TROUGH...BUT THE MODEL
CONSENSUS IS FORECASTING THE PRECIP WELL SOUTH AND EAST OF THE
FORECAST AREA. THE NUMERICAL GUIDANCE HAS BEEN A LITTLE
INCONSISTENT THE PAST COUPLE DAYS - UNDERSTANDABLE GIVEN HOW FAR
OUT WE ARE. THESE TROUGHS THAT DIG INTO THE SOUTHWEST CONUS AND
THEN LIFT OUT ALWAYS SEEM TO TAKE LONGER THAN WHAT THE MODELS
PREDICT. SO...BRINGING IN PRECIP FRIDAY NIGHT MIGHT BE A LITTLE
AGGRESSIVE AT THIS POINT. STILL A LOT OF UNCERTAINTY IN DAYS 6-8.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 611 PM CST SUN DEC 6 2015
LOW STRATUS/FOG SHOULD LINGER OVERNIGHT...WITH WIDESPREAD LIFR
CONDITIONS ANTICIPATED ACROSS CENTRAL MN...AND IFR CONDITIONS IN
WESTERN WI. HIGH PRESSURE WILL SLOWLY SHIFT EASTWARD...AND
SOUTHERLY WINDS WILL IMPROVE VISBYS SLIGHTLY...BUT FORECAST
SOUNDINGS SHOULD CLOUDS THROUGH MUCH OF MONDAY...SO HAVE CONTINUED
THAT TREND IN THE TAFS.
KMSP...
THE LOWEST VISBYS SHOULD STAY WEST OF MSP...BUT DONT SEE CIGS
RISING ABOVE 1000FT ANY EARLIER THAN MONDAY AFTERNOON. WINDS
SHOULD MAINTAIN A SOUTHERLY COMPONENT THROUGHOUT THE PERIOD.
/OUTLOOK FOR KMSP/
TUE...MVFR -RA POSSIBLE. WINDS SSW 5-10 KTS.
WED...VFR. WINDS SW 10 KTS.
THU...VFR WITH MVFR/-RA POSSIBLE. WIND W AT 10G20KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 8 AM CST MONDAY FOR MNZ042-043-049>051-
057>059-065>068-073>076-082>084-091-092.
&&
$$
SHORT TERM...RAH
LONG TERM...CLF
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS DULUTH MN
324 PM CST SAT DEC 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 240 PM CST SAT DEC 5 2015
HAVE INCREASED COVERAGE OF DRIZZLE AND INTRODUCED PATCHY FOG
OVERNIGHT AS FORECAST AREA REMAINS IN WARM SECTOR AHEAD OF 850HPA
TROUGH. A BROAD AREA OF LOW CLOUDS HAS DEVELOPED IN THE WARM AIR
ADVECTION REGIME AHEAD OF THE BOUNDARY. EXPECT CEILINGS TO
CONTINUE TO LOWER THROUGH THE EVENING WITH COOLING TEMPS AND
DEVELOPING PATCHY FOG AND DRIZZLE IN THE LATE EVENING AND
OVERNIGHT. CARRIED CLOUD COVER LONGER INTO SUNDAY MORNING FOR A
SLIGHTLY SLOWER TIMING OF THE FRONTAL PASSAGE AND CLEARING WITH
THE BUILDING RIDGE. TEMPERATURES WILL AGAIN BE MILD...WARMING INTO
THE UPPER 30S TO AROUND 40F.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 240 PM CST SAT DEC 5 2015
PLENTY OF UNCERTAINTY EXISTS THROUGH THE EXTENDED PERIOD WITH
SEVERAL LOW PRESSURE SYSTEMS IMPACTING THE NORTHLAND. THE
UNCERTAINTY STARTS TO RAMP UP AFTER MONDAY AND IS MOST PRONOUNCED
WITH A LATE WEEK/WEEKEND SYSTEM.
A QUASI ZONAL FLOW ALOFT WILL START OFF THE PERIOD WITH A MILD
SOUTHERLY FLOW KEEPING THE REGION DRY SUNDAY NIGHT INTO MONDAY
NIGHT. A SHORTWAVE WILL MOVE THROUGH THE AREA TUESDAY/TUESDAY NIGHT.
PRECIP TYPE WILL BE AN ISSUE WITH WARM AIR IN PLACE. AT THIS
TIME...WE WENT WITH RAIN TUESDAY...AND RAIN OR SNOW TUESDAY NIGHT.
DEPENDING ON THE TIMING OF THE PRECIPITATION...THERE COULD BE A
PERIOD OF LIGHT FREEZING DRIZZLE/RAIN. THE PRECIPITATION AMOUNTS
LOOK TO BE MAINLY LIGHT WITH THIS FIRST SYSTEM.
BOTH THE GFS AND ECMWF BRING A SECOND LOW PRESSURE SYSTEM INTO THE
REGION WEDNESDAY NIGHT INTO THURSDAY NIGHT. THE GFS IS FASTER THAN
THE ECMWF AND TRACKS THE SURFACE LOW A BIT FURTHER NORTH. A WINTRY
MIX WILL AGAIN BE POSSIBLE DUE TO WARM AIR STILL IN PLACE. THE ECMWF
IS SLOWER MOVING THE LOW THROUGH AND IS MORE BULLISH WITH ITS
QPF...ESPECIALLY OVER NORTHERN MINNESOTA.
THE GFS BRINGS IN AN AREA OF LOW PRESSURE TO SOUTHERN MINNESOTA BY
FRIDAY NIGHT...WITH THE ECMWF MUCH DIFFERENT DUE TO IT BEING BEING
SLOWER AND STRONGER WITH THE PREVIOUS LOW. BY 00Z SUNDAY...THE
GFS HAS A LOW JUST NORTH OF WESTERN LAKE SUPERIOR WITH THE ECMWF
SHOWING THE LOW STILL OVER THE CENTRAL PLAINS. MORE SNOW OR A WINTRY
MIX WILL BE POSSIBLE LATE IN THE WEEK INTO THE WEEKEND.
THE ONE THING THAT SEEMS MORE CERTAIN THROUGH THE EXTENDED IS THAT
HIGH TEMPERATURES SHOULD REMAIN ABOVE NORMAL THROUGH MOST OF THE
PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1205 PM CST SAT DEC 5 2015
AN MVFR DECK HAS DEVELOPED AHEAD OF A COLD FRONT MOVING INTO THE
FORECAST AREA FROM THE EASTERN DAKOTAS. THE LATEST RAP AND NAM
HAVE A PRETTY GOOD HANDLE ON THIS MVFR DECK MOVING IN...SO LEANED
TOWARDS THIS GUIDANCE IN THE LATEST TAF SET. AS THE FRONT MOVES
THROUGH EXPECTING SPOTTY SHOWERS OR DRIZZLE TO DEVELOP THIS
EVENING. THE COMBINATION OF MILD TEMPERATURES...LIGHT
WINDS...PRECIPITATION AND MELTING SNOW WILL RESULT IN FOG
DEVELOPING AT ALL TERMINALS THIS EVENING AND OVERNIGHT. THIS WILL
RESULT IN IFR CIGS/VISBY DEVELOPING TONIGHT INTO SUNDAY MORNING.
SUSPECT KHYR COULD SEE LIFR CONDITIONS...HOWEVER UNCERTAIN ON WHEN
EXACTLY THIS WILL OCCUR AT THIS POINT IN TIME. AFTER THE FRONT
PASSES...EXPECTING VFR CONDITIONS TO RETURN AFTER 10-12Z AT ALL
LOCATIONS EXCEPT FOR KHYR WHERE THE LOW CLOUDS AND FOG MAY
LINGER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 33 41 25 40 / 20 10 0 0
INL 27 39 22 41 / 10 0 0 0
BRD 29 41 24 42 / 10 10 0 0
HYR 34 42 22 43 / 20 20 0 0
ASX 35 43 24 43 / 20 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-140-
141-146>148.
&&
$$
SHORT TERM...GRANING
LONG TERM...MELDE
AVIATION...WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
1205 PM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1000 AM CST SAT DEC 5 2015
HAVE INCREASED TEMPS TODAY AS THE 50KT LLJ HAS KEPT A WARM
SOUTHERLY FLOW OVER THE REGION. LATEST SATELLITE IMAGERY SHOWS
MOSTLY SUNNY SKIES CURRENTLY OVER THE NORTHLAND. AN AREA OF HIGH
CLOUDS WAS COVERING SOUTHWEST MINNESOTA...PUSHING TOWARDS THE
NORTHEAST. THERE IS STILL SOME UNCERTAINTY IN THE LOW CLOUD
DEVELOPMENT ALONG AN 800HPA TROUGH SITUATED IN CENTRAL MN.
ALTHOUGH LATEST BUFR SOUNDINGS SHOW THE LOW LEVEL MOISTURE IS
LIMITED TO A VERY SHALLOW NEAR BOUNDARY LAYER...A FEW STATIONS IN
NORTH CENTRAL MN ARE STARTING TO REPORT FEW CLOUDS AROUND 20 KFT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
MINNESOTA IS IN A WARM SECTOR AHEAD OF A COLD FRONT EXTENDING NORTH-
SOUTH ACROSS THE DAKOTAS FROM A SURFACE LOW OVER NORTHERN MANITOBA.
THE WARM SECTOR IS QUITE MILD...WITH SURFACE TEMPERATURES IN THE
MIDDLE AND UPPER 30S ACROSS MOST OF NORTHERN MINNESOTA AND
WISCONSIN. BEHIND THE COLD FRONT IS NOT DRAMATICALLY COLDER BUT
TEMPERATURES DO FALL INTO THE UPPER 20S AND LOWER 30S FAIRLY
QUICKLY. THIS COLD FRONT TO SLOWLY MOVE INTO THE FORECAST AREA
TODAY...BECOMING MORE AND MORE DIFFUSE AS IT MOVES EAST TONIGHT AND
EARLY SUNDAY. THIS FEATURE TO BE A FOCUS FOR MID LEVEL MOISTURE TO
STREAM UP INTO THE AREA AND WITH SOME WEAK LIFT ALONG THE BOUNDARY
HAVE PUT IN SOME SHOWERS TONIGHT AND EARLY SUNDAY MORNING. MODELS
ARE TRYING TO PUT IN A NEARLY SATURATED BOUNDARY LAYER...BUT HAVE
SIGNIFICANT CONCERNS ON THIS AS CURRENT MODEL SOUNDINGS ARE OVER
SATURATED AND TOO COLD AT THE SURFACE NOW...AND ONLY GET WORSE IN
THE NEXT 24 HOURS. IN ADDITION THERE IS NO SIGN OF OF STRATUS IN
THE UPSTREAM AIRMASS OVER NORTH DAKOTA AND SOUTHERN
MANITOBA/SASKATCHEWAN...AND WOULD PREFER TO SEE SOME SIGNS OF IT
THERE BY NOW. WE HAVE ALSO SEEN A PATTERN RECENTLY OF THE MODELS
OVERDOING THE LOW LEVEL MOISTURE IN THIS PATTERN. THUS...HAVE
SWITCHED THE FORECAST OVER TO SLIGHT CHANCES OF SHOWERS. WITH THE
CLOUD COVER AROUND HAVE ALSO REDUCED THE DIURNAL RANGE AND BROUGHT
UP THE MIN TEMPS IN THE VICINITY OF THE FRONT FOR MAINLY LIQUID
SHOWERS IN THE EVENING... TRANSITIONING TO SNOW OVERNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
THE LONG TERM IS STARTING TO SOUND LIKE A BROKEN RECORD...AS
UNSEASONABLY WARM WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE
PERIOD. UPPER LEVEL RIDGING SUNDAY NIGHT AND EARLY MONDAY WILL BRING
A QUIET AND WARM START TO THE WORK WEEK. WITH A GOOD DEAL OF
SUNSHINE...TEMPERATURES SHOULD TOP OUT IN THE 39 TO 44 DEGREE RANGE.
TO PUT THAT IN PERSPECTIVE...NORMAL HIGH TEMPERATURES FOR THIS TIME
OF YEAR ARE GENERALLY IN THE LOW TO MID 20S. THE UPPER LEVEL FLOW
WILL THEN QUICKLY TRANSITION TO A QUASI-ZONAL FLOW BY MONDAY AND
MONDAY NIGHT...WITH A SHORTWAVE PUSHING EASTWARD ACROSS THE CWA
LATER TUESDAY AND TUESDAY NIGHT. WILL MENTION SOME SMALL POPS
REGARDING THIS SYSTEM BUT BEST CHANCE LOOKS TO BE SOUTH OF THE CWA.
THE MODELS ONCE AGAIN START TO DIVERGE FROM WEDNESDAY INTO FRIDAY OF
NEXT WEEK...SO THE CONFIDENCE IN ANY PARTICULAR SOLUTION CONTINUES
TO BE LOWER THAN AVERAGE. IN TERMS OF SENSIBLE WEATHER THE IMPACT IS
NOT TOO GREAT...AS IT DOES LOOK LIKE PRECIPITATION CHANCES WILL
EXIST NO MATTER WHICH MODEL...AND TEMPS APPEAR TO CONTINUE ABOVE
NORMAL. THROUGHOUT THE PERIOD WE SHOULD SEE HIGH TEMPERATURES RANGE
FROM THE MID 30S TO THE MID 40S...WITH LOWS IN THE 20S TO 30S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1205 PM CST SAT DEC 5 2015
AN MVFR DECK HAS DEVELOPED AHEAD OF A COLD FRONT MOVING INTO THE
FORECAST AREA FROM THE EASTERN DAKOTAS. THE LATEST RAP AND NAM
HAVE A PRETTY GOOD HANDLE ON THIS MVFR DECK MOVING IN...SO LEANED
TOWARDS THIS GUIDANCE IN THE LATEST TAF SET. AS THE FRONT MOVES
THROUGH EXPECTING SPOTTY SHOWERS OR DRIZZLE TO DEVELOP THIS
EVENING. THE COMBINATION OF MILD TEMPERATURES...LIGHT
WINDS...PRECIPITATION AND MELTING SNOW WILL RESULT IN FOG
DEVELOPING AT ALL TERMINALS THIS EVENING AND OVERNIGHT. THIS WILL
RESULT IN IFR CIGS/VISBY DEVELOPING TONIGHT INTO SUNDAY MORNING.
SUSPECT KHYR COULD SEE LIFR CONDITIONS...HOWEVER UNCERTAIN ON WHEN
EXACTLY THIS WILL OCCUR AT THIS POINT IN TIME. AFTER THE FRONT
PASSES...EXPECTING VFR CONDITIONS TO RETURN AFTER 10-12Z AT ALL
LOCATIONS EXCEPT FOR KHYR WHERE THE LOW CLOUDS AND FOG MAY
LINGER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 46 32 42 27 / 10 20 0 0
INL 44 27 39 25 / 10 0 0 0
BRD 43 28 41 24 / 10 10 0 0
HYR 47 34 42 22 / 10 20 0 0
ASX 49 35 43 25 / 10 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-140-
141-146>148.
&&
$$
UPDATE...GRANING
SHORT TERM...LE
LONG TERM...DAP
AVIATION...WL
AREA FORECAST DISCUSSION
NWS DULUTH MN
1016 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1000 AM CST SAT DEC 5 2015
HAVE INCREASED TEMPS TODAY AS THE 50KT LLJ HAS KEPT A WARM
SOUTHERLY FLOW OVER THE REGION. LATEST SATELLITE IMAGERY SHOWS
MOSTLY SUNNY SKIES CURRENTLY OVER THE NORTHLAND. AN AREA OF HIGH
CLOUDS WAS COVERING SOUTHWEST MINNESOTA...PUSHING TOWARDS THE
NORTHEAST. THERE IS STILL SOME UNCERTAINTY IN THE LOW CLOUD
DEVELOPMENT ALONG AN 800HPA TROUGH SITUATED IN CENTRAL MN.
ALTHOUGH LATEST BUFR SOUNDINGS SHOW THE LOW LEVEL MOISTURE IS
LIMITED TO A VERY SHALLOW NEAR BOUNDARY LAYER...A FEW STATIONS IN
NORTH CENTRAL MN ARE STARTING TO REPORT FEW CLOUDS AROUND 20 KFT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
MINNESOTA IS IN A WARM SECTOR AHEAD OF A COLD FRONT EXTENDING NORTH-
SOUTH ACROSS THE DAKOTAS FROM A SURFACE LOW OVER NORTHERN MANITOBA.
THE WARM SECTOR IS QUITE MILD...WITH SURFACE TEMPERATURES IN THE
MIDDLE AND UPPER 30S ACROSS MOST OF NORTHERN MINNESOTA AND
WISCONSIN. BEHIND THE COLD FRONT IS NOT DRAMATICALLY COLDER BUT
TEMPERATURES DO FALL INTO THE UPPER 20S AND LOWER 30S FAIRLY
QUICKLY. THIS COLD FRONT TO SLOWLY MOVE INTO THE FORECAST AREA
TODAY...BECOMING MORE AND MORE DIFFUSE AS IT MOVES EAST TONIGHT AND
EARLY SUNDAY. THIS FEATURE TO BE A FOCUS FOR MID LEVEL MOISTURE TO
STREAM UP INTO THE AREA AND WITH SOME WEAK LIFT ALONG THE BOUNDARY
HAVE PUT IN SOME SHOWERS TONIGHT AND EARLY SUNDAY MORNING. MODELS
ARE TRYING TO PUT IN A NEARLY SATURATED BOUNDARY LAYER...BUT HAVE
SIGNIFICANT CONCERNS ON THIS AS CURRENT MODEL SOUNDINGS ARE OVER
SATURATED AND TOO COLD AT THE SURFACE NOW...AND ONLY GET WORSE IN
THE NEXT 24 HOURS. IN ADDITION THERE IS NO SIGN OF OF STRATUS IN
THE UPSTREAM AIRMASS OVER NORTH DAKOTA AND SOUTHERN
MANITOBA/SASKATCHEWAN...AND WOULD PREFER TO SEE SOME SIGNS OF IT
THERE BY NOW. WE HAVE ALSO SEEN A PATTERN RECENTLY OF THE MODELS
OVERDOING THE LOW LEVEL MOISTURE IN THIS PATTERN. THUS...HAVE
SWITCHED THE FORECAST OVER TO SLIGHT CHANCES OF SHOWERS. WITH THE
CLOUD COVER AROUND HAVE ALSO REDUCED THE DIURNAL RANGE AND BROUGHT
UP THE MIN TEMPS IN THE VICINITY OF THE FRONT FOR MAINLY LIQUID
SHOWERS IN THE EVENING... TRANSITIONING TO SNOW OVERNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
THE LONG TERM IS STARTING TO SOUND LIKE A BROKEN RECORD...AS
UNSEASONABLY WARM WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE
PERIOD. UPPER LEVEL RIDGING SUNDAY NIGHT AND EARLY MONDAY WILL BRING
A QUIET AND WARM START TO THE WORK WEEK. WITH A GOOD DEAL OF
SUNSHINE...TEMPERATURES SHOULD TOP OUT IN THE 39 TO 44 DEGREE RANGE.
TO PUT THAT IN PERSPECTIVE...NORMAL HIGH TEMPERATURES FOR THIS TIME
OF YEAR ARE GENERALLY IN THE LOW TO MID 20S. THE UPPER LEVEL FLOW
WILL THEN QUICKLY TRANSITION TO A QUASI-ZONAL FLOW BY MONDAY AND
MONDAY NIGHT...WITH A SHORTWAVE PUSHING EASTWARD ACROSS THE CWA
LATER TUESDAY AND TUESDAY NIGHT. WILL MENTION SOME SMALL POPS
REGARDING THIS SYSTEM BUT BEST CHANCE LOOKS TO BE SOUTH OF THE CWA.
THE MODELS ONCE AGAIN START TO DIVERGE FROM WEDNESDAY INTO FRIDAY OF
NEXT WEEK...SO THE CONFIDENCE IN ANY PARTICULAR SOLUTION CONTINUES
TO BE LOWER THAN AVERAGE. IN TERMS OF SENSIBLE WEATHER THE IMPACT IS
NOT TOO GREAT...AS IT DOES LOOK LIKE PRECIPITATION CHANCES WILL
EXIST NO MATTER WHICH MODEL...AND TEMPS APPEAR TO CONTINUE ABOVE
NORMAL. THROUGHOUT THE PERIOD WE SHOULD SEE HIGH TEMPERATURES RANGE
FROM THE MID 30S TO THE MID 40S...WITH LOWS IN THE 20S TO 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 533 AM CST SAT DEC 5 2015
VFR CONDITIONS ARE EXPECTED TO MAKE A DRAMATIC TRANSITION AS THE
DAY WEARS ON ACROSS THE TAF SITES. HIGH RESOLUTION MODELS SUCH AS
THE HRRR AND RAP INDICATE THE DEVELOPMENT IN PLACE OF LOW CLOUDS
AND FOG AS THE DAY WEARS ON. THE LOW CLOUDS AND FOG ARE EXPECTED
TO DEVELOP ALONG AND AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS
THE NORTHLAND TODAY AND TONIGHT. THE FRONT WILL BRING SOME SPOTTY
SHOWERS OR DRIZZLE...BUT THE BIG STORY WILL BE THE DEVELOPMENT OF
MVFR AND EVENTUALLY IFR CIGS/VSBYS. THESE CONDITIONS WILL PERSIST
INTO THE NIGHT. STRONG LLWS WILL CONTINUE AT LEAST THROUGH THE
MORNING AND INTO THE AFTERNOON IN SOME SPOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 46 32 42 27 / 10 20 0 0
INL 44 27 39 25 / 10 0 0 0
BRD 43 28 41 24 / 10 10 0 0
HYR 47 34 42 22 / 10 20 0 0
ASX 49 35 43 25 / 10 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-140-
141-146>148.
&&
$$
UPDATE...GRANING
SHORT TERM...LE
LONG TERM...DAP
AVIATION...DAP
AREA FORECAST DISCUSSION
NWS DULUTH MN
537 AM CST SAT DEC 5 2015
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
MINNESOTA IS IN A WARM SECTOR AHEAD OF A COLD FRONT EXTENDING NORTH-
SOUTH ACROSS THE DAKOTAS FROM A SURFACE LOW OVER NORTHERN MANITOBA.
THE WARM SECTOR IS QUITE MILD...WITH SURFACE TEMPERATURES IN THE
MIDDLE AND UPPER 30S ACROSS MOST OF NORTHERN MINNESOTA AND
WISCONSIN. BEHIND THE COLD FRONT IS NOT DRAMATICALLY COLDER BUT
TEMPERATURES DO FALL INTO THE UPPER 20S AND LOWER 30S FAIRLY
QUICKLY. THIS COLD FRONT TO SLOWLY MOVE INTO THE FORECAST AREA
TODAY...BECOMING MORE AND MORE DIFFUSE AS IT MOVES EAST TONIGHT AND
EARLY SUNDAY. THIS FEATURE TO BE A FOCUS FOR MID LEVEL MOISTURE TO
STREAM UP INTO THE AREA AND WITH SOME WEAK LIFT ALONG THE BOUNDARY
HAVE PUT IN SOME SHOWERS TONIGHT AND EARLY SUNDAY MORNING. MODELS
ARE TRYING TO PUT IN A NEARLY SATURATED BOUNDARY LAYER...BUT HAVE
SIGNIFICANT CONCERNS ON THIS AS CURRENT MODEL SOUNDINGS ARE OVER
SATURATED AND TOO COLD AT THE SURFACE NOW...AND ONLY GET WORSE IN
THE NEXT 24 HOURS. IN ADDITION THERE IS NO SIGN OF OF STRATUS IN
THE UPSTREAM AIRMASS OVER NORTH DAKOTA AND SOUTHERN
MANITOBA/SASKATCHEWAN...AND WOULD PREFER TO SEE SOME SIGNS OF IT
THERE BY NOW. WE HAVE ALSO SEEN A PATTERN RECENTLY OF THE MODELS
OVERDOING THE LOW LEVEL MOISTURE IN THIS PATTERN. THUS...HAVE
SWITCHED THE FORECAST OVER TO SLIGHT CHANCES OF SHOWERS. WITH THE
CLOUD COVER AROUND HAVE ALSO REDUCED THE DIURNAL RANGE AND BROUGHT
UP THE MIN TEMPS IN THE VICINITY OF THE FRONT FOR MAINLY LIQUID
SHOWERS IN THE EVENING... TRANSITIONING TO SNOW OVERNIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 351 AM CST SAT DEC 5 2015
THE LONG TERM IS STARTING TO SOUND LIKE A BROKEN RECORD...AS
UNSEASONABLY WARM WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE
PERIOD. UPPER LEVEL RIDGING SUNDAY NIGHT AND EARLY MONDAY WILL BRING
A QUIET AND WARM START TO THE WORK WEEK. WITH A GOOD DEAL OF
SUNSHINE...TEMPERATURES SHOULD TOP OUT IN THE 39 TO 44 DEGREE RANGE.
TO PUT THAT IN PERSPECTIVE...NORMAL HIGH TEMPERATURES FOR THIS TIME
OF YEAR ARE GENERALLY IN THE LOW TO MID 20S. THE UPPER LEVEL FLOW
WILL THEN QUICKLY TRANSITION TO A QUASI-ZONAL FLOW BY MONDAY AND
MONDAY NIGHT...WITH A SHORTWAVE PUSHING EASTWARD ACROSS THE CWA
LATER TUESDAY AND TUESDAY NIGHT. WILL MENTION SOME SMALL POPS
REGARDING THIS SYSTEM BUT BEST CHANCE LOOKS TO BE SOUTH OF THE CWA.
THE MODELS ONCE AGAIN START TO DIVERGE FROM WEDNESDAY INTO FRIDAY OF
NEXT WEEK...SO THE CONFIDENCE IN ANY PARTICULAR SOLUTION CONTINUES
TO BE LOWER THAN AVERAGE. IN TERMS OF SENSIBLE WEATHER THE IMPACT IS
NOT TOO GREAT...AS IT DOES LOOK LIKE PRECIPITATION CHANCES WILL
EXIST NO MATTER WHICH MODEL...AND TEMPS APPEAR TO CONTINUE ABOVE
NORMAL. THROUGHOUT THE PERIOD WE SHOULD SEE HIGH TEMPERATURES RANGE
FROM THE MID 30S TO THE MID 40S...WITH LOWS IN THE 20S TO 30S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 533 AM CST SAT DEC 5 2015
VFR CONDITIONS ARE EXPECTED TO MAKE A DRAMATIC TRANSITION AS THE
DAY WEARS ON ACROSS THE TAF SITES. HIGH RESOLUTION MODELS SUCH AS
THE HRRR AND RAP INDICATE THE DEVELOPMENT IN PLACE OF LOW CLOUDS
AND FOG AS THE DAY WEARS ON. THE LOW CLOUDS AND FOG ARE EXPECTED
TO DEVELOP ALONG AND AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS
THE NORTHLAND TODAY AND TONIGHT. THE FRONT WILL BRING SOME SPOTTY
SHOWERS OR DRIZZLE...BUT THE BIG STORY WILL BE THE DEVELOPMENT OF
MVFR AND EVENTUALLY IFR CIGS/VSBYS. THESE CONDITIONS WILL PERSIST
INTO THE NIGHT. STRONG LLWS WILL CONTINUE AT LEAST THROUGH THE
MORNING AND INTO THE AFTERNOON IN SOME SPOTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 41 31 42 27 / 10 20 0 0
INL 42 26 39 25 / 10 0 0 0
BRD 41 27 41 24 / 10 10 0 0
HYR 45 33 42 22 / 10 20 0 0
ASX 47 34 43 25 / 10 20 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 PM CST THIS EVENING FOR LSZ121-
146>148.
&&
$$
SHORT TERM...LE
LONG TERM...DAP
AVIATION...DAP
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
915 PM CST SUN DEC 6 2015
.UPDATE:
Issued at 914 PM CST Sun Dec 6 2015
Just a few light showers remain over south central Illinois at
this hour. These showers should move out of the CWA by late
evening as upper low rotates away from the area. Still seeing
quite a few low clouds over all but the farthest southwestern and
southern counties. HRRR and RAP still is showing areas of dense
fog developing overnight across central and southeast Missouri
where these clear skies are most likely to persist.
Britt
&&
.SHORT TERM: (Tonight and Monday)
Issued at 245 PM CST Sun Dec 6 2015
Potent short wave trof moving through the Mid MS Valley has more
bark than bite and has only managed some small bands of light rain
as the forcing moved into the CWA. This trof and the associated
forcing will exit east into the OH Valley by mid evening, thus
will be mentioning a low chance of rain early this evening to the
east of the MS River. Complications arise in the wake of this
system and the potential for low clouds and fog. System related
clouds aoa 5kft currently blanketing the CWA will shift to the
east, while low stratus over IA will advect into western portions
of the CWA this evening. This low stratus will then slowly advect
into eastern MO later tonight. There are strong indications with
many of the shorter range models, especially the HRRR and SREF,
that dense fog will develop in its wake in an arcing N/S band from
western MO into central MO where sfc winds will become light in
association weak surface ridging. At this time I have mentioned
areas of dense fog late tonight into Monday morning. If the HRRR
is correct then an advisory may ultimately be warranted.
Clouds and fog should clear out west to east on Monday as the
surface ridge moves east and south to westerly flow gets underway
in the lower trop. This should allow for temps to rebound to above
average levels by afternoon.
Glass
.LONG TERM: (Monday through Next Sunday)
Issued at 245 PM CST Sun Dec 6 2015
A progressive flow regime will be in place this upcoming week and
this will lead to very mild temperatures running some 10 to 20
degrees above average. A couple of noteable but quick-moving shortwaves
and associated surface systems will impact the area within the
progressive flow with any cooling quite neglible.The first will
be Tuesday night and have some slight chance pops with it. Another
quick-moving shortwave trof moves across the area Thurs aft/night,
but the impact is primarily to our north. By the end of the week
there is a large scale pattern change with overall amplification
and development of a deep trof in the western U.S.. This trof
progresses into the central U.S. by next weekend leading to
increasing POPS and a greater threat of widespread rainfall.
Glass
&&
.AVIATION: (For the 00z TAFs through 00z Monday Evening)
Issued at 525 PM CST Sun Dec 6 2015
Upper trof continues to pull ewd out of the region, bringing an
end to the precip. Main questions will be impact of stratus and
development of FG. Believe area of ST with MVFR to IFR cigs will
continue to move sewd, but timing is uncertain. Sfc ridge is still
expected to build into the region with FG developing overnight. Do
not expect this FG to impact SUS/CPS unless ST does not move swd
quickly enuf. Expect ST/FG to gradually burn off during the
morning hours.
Specifics for KSTL: VFR cigs continue to move ewd out of the area.
Area of MVFR to IFR cigs is still expected to move swd, tho timing
is uncertain. Still expect conditions improving to VFR around 18z
Mon.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
545 PM CST SUN DEC 6 2015
.SHORT TERM: (Tonight and Monday)
Issued at 245 PM CST Sun Dec 6 2015
Potent short wave trof moving through the Mid MS Valley has more
bark than bite and has only managed some small bands of light rain
as the forcing moved into the CWA. This trof and the associated
forcing will exit east into the OH Valley by mid evening, thus
will be mentioning a low chance of rain early this evening to the
east of the MS River. Complications arise in the wake of this
system and the potential for low clouds and fog. System related
clouds aoa 5kft currently blanketing the CWA will shift to the
east, while low stratus over IA will advect into western portions
of the CWA this evening. This low stratus will then slowly advect
into eastern MO later tonight. There are strong indications with
many of the shorter range models, especially the HRRR and SREF,
that dense fog will develop in its wake in an arcing N/S band from
western MO into central MO where sfc winds will become light in
association weak surface ridging. At this time I have mentioned
areas of dense fog late tonight into Monday morning. If the HRRR
is correct then an advisory may ultimately be warranted.
Clouds and fog should clear out west to east on Monday as the
surface ridge moves east and south to westerly flow gets underway
in the lower trop. This should allow for temps to rebound to above
average levels by afternoon.
Glass
.LONG TERM: (Monday through Next Sunday)
Issued at 245 PM CST Sun Dec 6 2015
A progressive flow regime will be in place this upcoming week and
this will lead to very mild temperatures running some 10 to 20
degrees above average. A couple of noteable but quick-moving shortwaves
and associated surface systems will impact the area within the
progressive flow with any cooling quite neglible.The first will
be Tuesday night and have some slight chance pops with it. Another
quick-moving shortwave trof moves across the area Thurs aft/night,
but the impact is primarily to our north. By the end of the week
there is a large scale pattern change with overall amplification
and development of a deep trof in the western U.S.. This trof
progresses into the central U.S. by next weekend leading to
increasing POPS and a greater threat of widespread rainfall.
Glass
&&
.AVIATION: (For the 00z TAFs through 00z Monday Evening)
Issued at 525 PM CST Sun Dec 6 2015
Upper trof continues to pull ewd out of the region, bringing an
end to the precip. Main questions will be impact of stratus and
development of FG. Believe area of ST with MVFR to IFR cigs will
continue to move sewd, but timing is uncertain. Sfc ridge is still
expected to build into the region with FG developing overnight. Do
not expect this FG to impact SUS/CPS unless ST does not move swd
quickly enuf. Expect ST/FG to gradually burn off during the
morning hours.
Specifics for KSTL: VFR cigs continue to move ewd out of the area.
Area of MVFR to IFR cigs is still expected to move swd, tho timing
is uncertain. Still expect conditions improving to VFR around 18z
Mon.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1115 AM CST SAT DEC 5 2015
.UPDATE:
Issued at 1112 AM CST Sat Dec 5 2015
Dense fog dissipated a little ahead of schedule with mostly sunny
conditions expected the remainder of the afternoon. Forecast highs
look on target with middle 50s areawide.
CVKING
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 330 AM CST Sat Dec 5 2015
Once again, fog is the primary concern for the short term forecast
this morning. An expansive area of fog is advecting westward toward
the Mississippi River from Illinois and it looks likely to envelop
much of the STL Metro area before sunrise. Have already expanded
the dense fog advisory issued yesterday evening into east central
Missouri. HRRR and NARRE-TL look to have a pretty good handle on
the fog so far this morning...although they might be a little bit
too aggressive with the westward-southwestward expansion.
Regardless, both models keep visibility down through 14-15Z.
Improvement is pretty rapid between 16-18Z, so the timing of the
advisory still looks pretty good. Temperatures today should be
similar to yesterday, though some of the cooler readings over
central Illinois yesterday will likely expand further west-southwest
today due to the greater areal coverage of the fog today.
Carney
.LONG TERM: (Tonight through Friday)
Issued at 330 AM CST Sat Dec 5 2015
An extended period of above average temps continues to look likely
for much of next week as the polar jet, with very few exceptions,
remains to our north. The flow will overall be low amplitude,
facilitating a progressive movement to any systems, and indeed, our
area will be treated to a series of storm systems originating over
the Pacific that will be quick hitting, which will incidentally,
limit their ability to moisten the column sufficiently to allow
pcpn.
The first system is slated for Sunday, and this looks to be the one
where confidence is highest that it will produce pcpn for some
areas. Models have come together nicely on timing now that it is
over land and can be sampled better, ranging from beginning Sunday
morning over northeast and central MO, to exiting southwest IL by
late Sunday evening. There is also good consensus on track, with
the strongest lift associated with the core of the system expected
over northern MO and central IL, and have placed highest PoPs in
these areas as a result--corresponding to our northern CWA. Even
then, moisture will struggle with this system, with its relatively
fast movement, northern track, very dry column already in place, and
no help whatsoever from low level flow. So highest PoPs for this
system look to be just below 50% in the north, trailing to slight
chance 20% in southern MO and IL. Pcpn-types should be all rain
with warm air aloft and above freezing surface temps.
Additional fast moving Pacific systems will slide thru, Monday
night, Tuesday night, and again Thursday-Friday, but with marginal
conditions at best and specific tracks enough in doubt (large enough
model spreads) whereby they will need all the lift they can muster
to generate pcpn, leaned dry on the forecast for much of next week
for now, with PoPs possibly needed down the road as track confidence
increases.
Otherwise, very mild week on tap after Sunday, with what should be
daytime maxes at least in the 50s, possibly 60s, and nighttime mins
above freezing.
A pattern change looks set to occur for the third week of December,
with large height falls and a longwave TROF setting up over the
central CONUS. This should open the way for cold air intrusions
heading towards Christmas that we have not really seen thus far this
late autumn and early winter.
TES
&&
.AVIATION: (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1112 AM CST Sat Dec 5 2015
Dense fog has dissipated. VFR conditions expected the rest of the
day. Could see some valley fog develop again Sunday morning, but
mid deck of clouds should also be spreading east with the approach
of an upper level storm system. Not much moisture expected with
this system so have kept forecast dry at this time. Light
southeast wind to become southwest on Sunday.
Specifics for KSTL:
VFR conditions expected with a steady increase of high clouds
tonight and mid level clouds on Sunday. Can`t rule out some light
rain on Sunday, but confidence too low at this time to include in
the forecast. Light southeast wind will become southwest.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
556 AM CST SAT DEC 5 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 330 AM CST Sat Dec 5 2015
Once again, fog is the primary concern for the short term forecast
this morning. An expansive area of fog is advecting westward toward
the Mississippi River from Illinois and it looks likely to envelop
much of the STL Metro area before sunrise. Have already expanded
the dense fog advisory issued yesterday evening into east central
Missouri. HRRR and NARRE-TL look to have a pretty good handle on
the fog so far this morning...although they might be a little bit
too aggressive with the westward-southwestward expansion.
Regardless, both models keep visibility down through 14-15Z.
Improvement is pretty rapid between 16-18Z, so the timing of the
advisory still looks pretty good. Temperatures today should be
similar to yesterday, though some of the cooler readings over
central Illinois yesterday will likely expand further west-southwest
today due to the greater areal coverage of the fog today.
Carney
.LONG TERM: (Tonight through Friday)
Issued at 330 AM CST Sat Dec 5 2015
An extended period of above average temps continues to look likely
for much of next week as the polar jet, with very few exceptions,
remains to our north. The flow will overall be low amplitude,
facilitating a progressive movement to any systems, and indeed, our
area will be treated to a series of storm systems originating over
the Pacific that will be quick hitting, which will incidentally,
limit their ability to moisten the column sufficiently to allow
pcpn.
The first system is slated for Sunday, and this looks to be the one
where confidence is highest that it will produce pcpn for some
areas. Models have come together nicely on timing now that it is
over land and can be sampled better, ranging from beginning Sunday
morning over northeast and central MO, to exiting southwest IL by
late Sunday evening. There is also good consensus on track, with
the strongest lift associated with the core of the system expected
over northern MO and central IL, and have placed highest PoPs in
these areas as a result--corresponding to our northern CWA. Even
then, moisture will struggle with this system, with its relatively
fast movement, northern track, very dry column already in place, and
no help whatsoever from low level flow. So highest PoPs for this
system look to be just below 50% in the north, trailing to slight
chance 20% in southern MO and IL. Pcpn-types should be all rain
with warm air aloft and above freezing surface temps.
Additional fast moving Pacific systems will slide thru, Monday
night, Tuesday night, and again Thursday-Friday, but with marginal
conditions at best and specific tracks enough in doubt (large enough
model spreads) whereby they will need all the lift they can muster
to generate pcpn, leaned dry on the forecast for much of next week
for now, with PoPs possibly needed down the road as track confidence
increases.
Otherwise, very mild week on tap after Sunday, with what should be
daytime maxes at least in the 50s, possibly 60s, and nighttime mins
above freezing.
A pattern change looks set to occur for the third week of December,
with large height falls and a longwave TROF setting up over the
central CONUS. This should open the way for cold air intrusions
heading towards Christmas that we have not really seen thus far this
late autumn and early winter.
TES
&&
.AVIATION: (For the 12z TAFs through 12z Sunday Morning)
Issued at 538 AM CST Sat Dec 5 2015
Expansive area of fog and low stratus over Illinois was spreading
westward into east central Missouri; however, the western edges of
the fog are shredding out. High resolution/short range model
guidance is pretty insistent that at least some of these holes
will fill in over the next 90 minutes...although I have my doubts.
Regardless, widespread IFR ceilings/visibilities will prevail
east of the Mississippi river this morning until at least 16-18Z,
and likely over a small part of east central Missouri until
14-15Z. Elsewhere and otherwise, expect VFR flight conditions. and
light southeast flow.
Specifics for KSTL:
The approach of fog and low stratus toward Lambert has slowed
significantly over the past 60-90 minutes, and the once unbroken
fog bank is shredding on its western fringes. That being said,
satellite pictures and area traffic cameras show very low
visibilities within 5 miles of the airport, so I feel compelled to
keep some mention of IFR in the TAF. Additionally, high
resolution/short range model guidance is pretty insistent that at
least some of the holes on the western fringes of the fog bank will
fill in over the next 90 minutes...although I have my doubts. Fog
will persist in the area of the terminal for at least a couple of
hours this morning. VFR flight conditions with southeast flow will
prevail thereafter.
Carney
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Dense Fog Advisory until noon CST today FOR Jefferson MO-St.
Charles MO-St. Louis City MO-St. Louis MO-Ste. Genevieve MO.
IL...Dense Fog Advisory until noon CST today 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
NWS ST LOUIS MO
330 AM CST SAT DEC 5 2015
.SHORT TERM: (Through Late This Afternoon)
Issued at 330 AM CST Sat Dec 5 2015
Once again, fog is the primary concern for the short term forecast
this morning. An expansive area of fog is advecting westward toward
the Mississippi River from Illinois and it looks likely to envelop
much of the STL Metro area before sunrise. Have already expanded
the dense fog advisory issued yesterday evening into east central
Missouri. HRRR and NARRE-TL look to have a pretty good handle on
the fog so far this morning...although they might be a little bit
too aggressive with the westward-southwestward expansion.
Regardless, both models keep visibility down through 14-15Z.
Improvement is pretty rapid between 16-18Z, so the timing of the
advisory still looks pretty good. Temperatures today should be
similar to yesterday, though some of the cooler readings over
central Illinois yesterday will likely expand further west-southwest
today due to the greater areal coverage of the fog today.
Carney
.LONG TERM: (Tonight through Friday)
Issued at 330 AM CST Sat Dec 5 2015
An extended period of above average temps continues to look likely
for much of next week as the polar jet, with very few exceptions,
remains to our north. The flow will overall be low amplitude,
facilitating a progressive movement to any systems, and indeed, our
area will be treated to a series of storm systems originating over
the Pacific that will be quick hitting, which will incidentally,
limit their ability to moisten the column sufficiently to allow
pcpn.
The first system is slated for Sunday, and this looks to be the one
where confidence is highest that it will produce pcpn for some
areas. Models have come together nicely on timing now that it is
over land and can be sampled better, ranging from beginning Sunday
morning over northeast and central MO, to exiting southwest IL by
late Sunday evening. There is also good consensus on track, with
the strongest lift associated with the core of the system expected
over northern MO and central IL, and have placed highest PoPs in
these areas as a result--corresponding to our northern CWA. Even
then, moisture will struggle with this system, with its relatively
fast movement, northern track, very dry column already in place, and
no help whatsoever from low level flow. So highest PoPs for this
system look to be just below 50% in the north, trailing to slight
chance 20% in southern MO and IL. Pcpn-types should be all rain
with warm air aloft and above freezing surface temps.
Additional fast moving Pacific systems will slide thru, Monday
night, Tuesday night, and again Thursday-Friday, but with marginal
conditions at best and specific tracks enough in doubt (large enough
model spreads) whereby they will need all the lift they can muster
to generate pcpn, leaned dry on the forecast for much of next week
for now, with PoPs possibly needed down the road as track confidence
increases.
Otherwise, very mild week on tap after Sunday, with what should be
daytime maxes at least in the 50s, possibly 60s, and nighttime mins
above freezing.
A pattern change looks set to occur for the third week of December,
with large height falls and a longwave TROF setting up over the
central CONUS. This should open the way for cold air intrusions
heading towards Christmas that we have not really seen thus far this
late autumn and early winter.
TES
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1134 PM CST Fri Dec 4 2015
For COU/UIN...Winds will remain sely to ssely thru the TAF period
just above 10 kts for UIN and around 8 kts for COU.
Specifics for KSTL/KSUS/KCPS: Focus continues to be FG impacts.
Have moved back timing at all sites. Given the dewpoint spread at
SUS, believe FG will develop shortly. At STL/CPS, temps have not
dropped as quickly as previously thought due to continued mixing.
However, given potential for river FG to develop and the area of
dense FG over IL moving wwd, will move back timing of onset and
keep mention in the TAF for now.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...Dense Fog Advisory until noon CST today FOR Jefferson MO-St.
Charles MO-St. Louis City MO-St. Louis MO-Ste. Genevieve MO.
IL...Dense Fog Advisory until noon CST today 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
1148 PM CST FRI DEC 4 2015
.UPDATE:
Issued at 824 PM CST Fri Dec 4 2015
Have issued a dense fog advisory for the eastern counties as an
area of dense fog is spreading westward this evening now that the
boundary layer is becoming saturated after sunset. Visibilities
are already down to 3SM at Salem and are 1/4SM at Effingham and
Taylorville. Visibility guidance from the RAP and experimental
HRRR suggests that the dense fog may spread back to the
Mississippi river overnight, so may need to expand the advisory
again this evening. Where there are temperatures below freezing,
the fog may deposit some icing on roads which could produce some
slick spots. Rest of the forecast still looks on track.
Britt
&&
.SHORT TERM: (Through Late Tonight)
Issued at 321 PM CST Fri Dec 4 2015
Late this afternoon, an area of fog/stratus was located over
IL/IN near the center of a surface high. Some models show the
existing fog/stratus backbuilding overnight, especially an
expansion into southwest IL. This scenario does not seem
unreasonable given the presence of fog/stratus last night, the
observed slow erosion of fog/stratus today, moisture trapped
beneath an inversion noted on BUFKIT soundings, and the expected
wx conditions tonight (particularly the light winds and initially
clear skies over the eastern CWA which will promote radiational
cooling). If it develops, the thickest fog/stratus would be
expected over southwest and southern IL. Farther west, southerly
surface winds should remain strong enough to interfere with
widespread fog formation, although patchy fog cannot be ruled
out, especially with any breaks in the approaching cirrus
associated with a weak disturbance.
Kanofsky
.LONG TERM: (Saturday through Next Friday)
Issued at 321 PM CST Fri Dec 4 2015
The warming trend noted today (temperatures in the 50s by 21z)
will continue tomorrow. A stronger vort max then approaches the
region tomorrow night and could bring some light rain to the area
on Sunday, but moisture remains limited. This forecast maintains
fairly low PoPs for Sunday due to the limited moisture. The
latest model runs are in better agreement with a more progressive
solution, and most models have the upper vort center well east of
the area by 12z Mon. Persistent southerly to southwesterly flow
will help temperatures rebound into the mid-upper 50s during the
middle and late part of the week. A few other disturbances are
forecast to move across the central CONUS during the middle and
late part of next week, possibly bringing light pcpn to MO/IL.
Kanofsky
&&
.AVIATION: (For the 06z TAFs through 06z Saturday Night)
Issued at 1134 PM CST Fri Dec 4 2015
For COU/UIN...Winds will remain sely to ssely thru the TAF period
just above 10 kts for UIN and around 8 kts for COU.
Specifics for KSTL/KSUS/KCPS: Focus continues to be FG impacts.
Have moved back timing at all sites. Given the dewpoint spread at
SUS, believe FG will develop shortly. At STL/CPS, temps have not
dropped as quickly as previously thought due to continued mixing.
However, given potential for river FG to develop and the area of
dense FG over IL moving wwd, will move back timing of onset and
keep mention in the TAF for now.
Tilly
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...Dense Fog Advisory until noon CST Saturday FOR Bond IL-Clinton
IL-Fayette IL-Marion IL-Montgomery IL-Washington IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1125 AM CST SAT DEC 5 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
PCPN CHANCES TONIGHT AND TEMPS THE NEXT FEW DAYS ARE THE MAIN FCST
CONCERNS.
TROUGH OVER THE ROCKIES REMAINS PROGRESSIVE WITH 12 HOUR HEIGHT
FALLS AT 00Z AS HIGH AS 110 METERS AT KGGW. WEAKER HEIGHT FALLS
EXTENDED BACK TO THE S AND SW INTO SRN CA AND AZ. WATER VAPOR LOOP
IN COMBINATION WITH RECENT RUC MODEL INITIALIZATIONS SHOWED THE
TROUGH AXIS FROM NEAR THE ID/WY BORDER SWD INTO AZ. SFC ANLYS AT
09Z DEPICTED CDFNT FROM ERN ND INTO WRN NE.
EXPECT INCREASING/THICKENING CLOUD COVER FOR THE AREA TODAY AS THE
TROUGH OVER THE ROCKIES MOVES EWD. RAIN CHANCES SHOULD HOLD OFF
UNTIL AFTER 6 PM...THEN INCREASE AS LIFT CAUSES MID LEVEL
SATURATION. HIGH RESOLUTION GFS SEEMS TO HAVE A DECENT HANDLE ON
TIMING. PCPN AMOUNTS OVERNIGHT SHOULD BE FAIRLY LIGHT...AND FCST
SOUNDINGS SUGGEST PCPN TYPE REMAINING LIQUID. LINGERED A SLIGHT
CHANCE OF LIGHT RAIN IN SWRN IA AND THE SERN TIP OF NE. WEAK
RIDGING ALOFT MOVES IN LATER SUN...AND CLOUDS WILL DECREASE.
GENLY USED A BLEND OF AVAILABLE MOS GUIDANCE...WITH HIGHEST WEIGHT
GIVEN TO 00Z GFS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
KEPT THIS PERIOD MAINLY DRY. A FAST MOVING SHORTWAVE TROUGH WILL
MOVE INTO THE CNTRL PLAINS TUE...BUT MOISTURE LOOKS LIMITED FOR
OUR AREA. CHANCES ARE BEST FROM THE DKTS INTO MN AND NRN IA...BUT
WILL NEED TO WATCH THIS IN FUTURE MODEL RUNS. ANOTHER SHORTWAVE
TROUGH MOVES ACRS THE AREA THU...BUT AGAIN MOISTURE LOOKS LIMITED
FOR ERN NE AND SWRN IA. TEMPS SHOULD BE FAIRLY MILD THROUGH THE
PERIOD...WITH THU PROBABLY THE WARMEST DAY FOR KLNK AND KOMA.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1117 AM CST SAT DEC 5 2015
DESPITE THE FAIRLY STRONG SHORTWAVE AND FRONT MOVING THROUGH THE
REGION...THE TAF SITES SHOULD EXPERIECE MOSTLY VFR CONDITIONS
THROUGH THIS PERIOD. AN IFR CLOUD DECK WAS NOTED AT 17Z FROM
CENTRAL INTO NORTHEAST NEBRAKSA WITH CIGS008-014...BUT THIS SHOULD
MOVE NORTHEAST OUT OF THE REGION BY THIS EVENING. OTHERWISE KOMA-
KLNK MAY SEE A FEW HOURS OF OVC040 THIS EVENING WHILE THE FRONT
IS MOVING THROUGH. LIGHT SHOWERS MIGHT BE WIDELY SCATTERED THIS
EVENING BUT SHOULD HAVE LITTLE IMPACT ON VISIBILITY. OTHERWISE
WINDS SHIFT FROM SOUTH TO NORTHWEST AS THE FRONT PASSES.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...NIETFELD
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
335 AM CST SAT DEC 5 2015
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
PCPN CHANCES TONIGHT AND TEMPS THE NEXT FEW DAYS ARE THE MAIN FCST
CONCERNS.
TROUGH OVER THE ROCKIES REMAINS PROGRESSIVE WITH 12 HOUR HEIGHT
FALLS AT 00Z AS HIGH AS 110 METERS AT KGGW. WEAKER HEIGHT FALLS
EXTENDED BACK TO THE S AND SW INTO SRN CA AND AZ. WATER VAPOR LOOP
IN COMBINATION WITH RECENT RUC MODEL INITIALIZATIONS SHOWED THE
TROUGH AXIS FROM NEAR THE ID/WY BORDER SWD INTO AZ. SFC ANLYS AT
09Z DEPICTED CDFNT FROM ERN ND INTO WRN NE.
EXPECT INCREASING/THICKENING CLOUD COVER FOR THE AREA TODAY AS THE
TROUGH OVER THE ROCKIES MOVES EWD. RAIN CHANCES SHOULD HOLD OFF
UNTIL AFTER 6 PM...THEN INCREASE AS LIFT CAUSES MID LEVEL
SATURATION. HIGH RESOLUTION GFS SEEMS TO HAVE A DECENT HANDLE ON
TIMING. PCPN AMOUNTS OVERNIGHT SHOULD BE FAIRLY LIGHT...AND FCST
SOUNDINGS SUGGEST PCPN TYPE REMAINING LIQUID. LINGERED A SLIGHT
CHANCE OF LIGHT RAIN IN SWRN IA AND THE SERN TIP OF NE. WEAK
RIDGING ALOFT MOVES IN LATER SUN...AND CLOUDS WILL DECREASE.
GENLY USED A BLEND OF AVAILABLE MOS GUIDANCE...WITH HIGHEST WEIGHT
GIVEN TO 00Z GFS.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 335 AM CST SAT DEC 5 2015
KEPT THIS PERIOD MAINLY DRY. A FAST MOVING SHORTWAVE TROUGH WILL
MOVE INTO THE CNTRL PLAINS TUE...BUT MOISTURE LOOKS LIMITED FOR
OUR AREA. CHANCES ARE BEST FROM THE DKTS INTO MN AND NRN IA...BUT
WILL NEED TO WATCH THIS IN FUTURE MODEL RUNS. ANOTHER SHORTWAVE
TROUGH MOVES ACRS THE AREA THU...BUT AGAIN MOISTURE LOOKS LIMITED
FOR ERN NE AND SWRN IA. TEMPS SHOULD BE FAIRLY MILD THROUGH THE
PERIOD...WITH THU PROBABLY THE WARMEST DAY FOR KLNK AND KOMA.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1141 PM CST FRI DEC 4 2015
BRISK SOUTH WINDS TONIGHT 10 TO 16 KTS WITH VARIABLE GUSTS. DID
MENTION LOW LEVEL WIND SHEAR WITH AXIS OF H9 WINDS WITH 40 TO 50KT
JET. VFR CONDITIONS TONIGHT WITH INCREASING CLOUDS FOR SATURDAY.
THE WINDS DECREASE AS THE FRONT APPROACHES WITH A FROPA AND WINDS
SWITCHING AROUND TO THE NORTH AT KOFK AROUND 00Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
644 AM EST SAT DEC 5 2015
.SYNOPSIS...
CLOUDS WILL GRADUALLY GIVE WAY TO SUNSHINE TODAY WITH TEMPERATURES
IN THE 40S. FULL SUNSHINE IS EXPECTED SUNDAY WITH HIGHS INTO THE
50S. DRY AND MILD WEATHER WILL CONTINUE INTO MUCH OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE...
CLOUDS STILL HOLDING TOUGH OVER OUR AREA WITH THE ONLY AREA SEEING
A CLEAR SKY OVER SULLIVAN AND PIKE COUNTIES. BASED ON THIS AND THE
LATEST RUC SLOWING THE CLEARING TODAY, CONTINUED A CLOUDY SKY FOR
MOST OF THE AREA THROUGH LATE THIS MORNING. A CLEARING TREND FROM
SOUTH TO NORTH IS STILL EXPECTED BUT NOT UNTIL LATE MORNING NEPA,
AFTERNOON SOUTHERN TIER OF NY, AND PERHAPS NOT UNTIL TOWARD SUNSET
CENTRAL NY. PREVIOUS AFD, INCLUDING A SUNNIER END TO THE WEEKEND,
IS BELOW.
315 AM UPDATE...
JUST A CLOUD AND TEMPERATURE FORECAST TODAY. LOW LEVEL CLOUDS HAVE
EXPANDED TO COVER ALMOST ALL OF OUR FORECAST AREA, OUTSIDE OF
SULLIVAN COUNTY. WITH A NORTHERLY OR UPSLOPE COMPONENT OF THE
WIND, THIS IS NO SURPRISE GIVEN THE TIME OF THE MORNING. WITH
SURFACE HIGH PRESSURE MOVING OVERHEAD BY 12Z AND OUR WIND BECOMING
NEARLY CALM, SUBSIDENCE OR SINKING AIR WILL SLOWLY ERODE OUR CLOUD
DECK FROM SOUTH TO NORTH. WITH THAT IN MIND EXPECT A GRADUAL
INCREASE IN SUNSHINE TODAY BUT FROM THE NORTHERN TIER OF PA INTO
MUCH OF SOUTHERN NY, THIS MAY TAKE UNTIL AT LEAST MIDDAY TO OCCUR.
FARTHER NORTH TOWARD SYRACUSE, WE MAY NOT SEE CLEARING UNTIL LATER
THIS AFTERNOON. BASED ON THE CLOUDS I LOWERED HIGH TEMPS A BIT
TODAY WITH NEARLY STEADY TEMPS UNTIL A LATE DAY SPIKE IN TEMPS
OCCURRING WITH OUR CLEARING. WITH A CLEAR SKY AND NEAR CALM
CONDITIONS TONIGHT WILL BE MUCH COLDER THAN RIGHT NOW, WITH MANY
AREAS FALLING BACK INTO THE 20S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
315 AM UPDATE....
A BEAUTIFUL END TO OUR WEEKEND, WITH MORE SUNSHINE EXPECTED AND IN
RESPONSE IT WILL BE WARMER AT THE SURFACE. HIGHS WILL BE IN THE
50S OR WELL ABOVE OUR EARLY DECEMBER AVERAGE OF 36 TO 40 DEGREES!
A DISTURBANCE IN THE JET STREAM WINDS ALOFT WILL MOVE OUT OF THE
OHIO VALLEY MONDAY, AND ACROSS OUR AREA MONDAY NIGHT. ANY
PRECIPITATION (IN THE FORM OF RAIN) ASSOCIATED WITH THIS SYSTEM
WILL REMAIN SOUTH OF OUR AREA. THE IMPACT OF THE DISTURBANCE
HOWEVER WILL BE A COOLER POCKET OF AIR MOVING OVER AREA AREA. THE
RESULT WILL BE HIGHS MONDAY ABOUT 5 TO 8 DEGREES COOLER THAN WHAT
WE WILL SEE TODAY. STILL WE ARE TALKING WELL INTO THE 40S FOR
MOST, AND NEAR 50 FAR SOUTH. FOR DECEMBER 7TH, NOT TOO SHABBY!
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
3 PM FRI UPDATE...
ANOTHER WARM PERIOD WITH LITTLE PRECIPITATION. HIGHS IN THE 40S
AND LOWS IN THE 30S. FOLLOWED WPC LEAD AND LEFT POPS AT SLIGHT
CHANCE WED NGT TO FRIDAY. A MORE ACTIVE PATTERN WITH A ZONAL
PATTERN BECOMING AMPLIFIED END OF WEEK. A WEAK CLOSED UPPER LEVEL
LOW MOVES THROUGH MONDAY AND EAST TUESDAY. HIGH PRESSURE AND DRY
AIR SHOULD KEEP ANY RAIN TO THE COASTAL PLAIN AND OUT OF OUR CWA.
WED TO SAT MODEL DISAGREEMENT BUT A SERIES OF SHORT WAVES AS AN
UPPER LEVEL TROF APPROACHES. EURO DEEPER AND WETTER THAN GFS.
WEATHER NOT A PROBLEM WITH TEMPERATURES AT THE SFC AND 850MB ABOVE
FREEZING.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
STUBBORN SC DECK CONTS OVER THE AREA THIS MRNG...AND MAY LINGER
FOR MUCH OF THE DAY. MESO MODELS SHOW SLOW EROSION OF THE DECK
FROM THE SOUTH...NOT RCHG RME AND SYR UNTIL ALMOST DARK. WILL CONT
WITH MVFR CIGS ALL STATIONS THIS MRNG...SLOWLY BCMG SCT FROM SOUTH
TO NORTH BEGINING ARND 16Z AT AVP. UNDER SFC HIPRES...WINDS WILL
REMAIN LGT. MAINLY CLR SKIES XPCTD OVRNGT.
.OUTLOOK...
SAT NIGHT THROUGH WED...QUIET PERIOD. MAINLY VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...HEDEN
NEAR TERM...HEDEN
SHORT TERM...HEDEN
LONG TERM...TAC
AVIATION...DGM
AREA FORECAST DISCUSSION
NWS BUFFALO NY
637 AM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY WITH A GRADUAL
RETURN TO SUNSHINE AND ABOVE AVERAGE TEMPERATURES. THE CLEAR
SKIES AND WARM TEMPERATURES WILL CONTINUE SUNDAY AND RIGHT THROUGH
THE FIRST HALF OF NEXT WEEK AS HIGH PRESSURE REMAINS IN CONTROL.
&&
.NEAR TERM /THROUGH TONIGHT/...
A WIDESPREAD LOW STRATUS DECK LODGED UNDERNEATH A STEEP
SUBSIDENCE INVERSION WITHIN THE BACKGROUND OF WEAK SURFACE RIDGING
CONTINUING TO ENCOMPASSING MUCH OF WESTERN NEW YORK. 1000-975 MB
MOISTURE FIELDS ON THE HRRR AND RAP CONCUR WITH THE CURRENT
PLACEMENT OF THIS CLOUD DECK. CLOUDS WILL BE STUBBORN TO CLEAR
WITH CURRENT TRENDS POINTING TOWARD TAKING A DECIDEDLY MORE
PESSIMISTIC OUTLOOK ON CLOUD COVER NEARLY AREAWIDE THROUGH THE
MORNING PERIOD. ELEMENT OF SHALLOW FOG WITHIN THIS NEAR SURFACE
MOISTURE PLUME AS WELL.
STRATUS/FOG SHOULD ERODE FOR THE MOST PART BY AFTERNOON...ALTHOUGH
COULD CONTINUE TO LINGER ACROSS INTERIOR SECTIONS EAST OF LAKE
ONTARIO. INCREASING SUNSHINE ALONG WITH DEVELOPING WARM AIR
ADVECTION PATTERN SHOULD GET AFTERNOON TEMPERATURES IN THE LOWER
50S ON THE LAKE PLAINS OF WESTERN NEW YORK AND MID TO UPPER 40S
ACROSS HIGHER TERRAIN AND THE EASTERN LAKE ONTARIO REGION.
BY SUNDAY...SURFACE HIGH PRESSURE AND MID LEVEL RIDGING WILL SHIFT
OFF THE MID-ATLANTIC AND NEW ENGLAND COASTS. AMPLE SUNSHINE ALONG
WITH A SOUTHERLY FLOW AND 850 MB TEMPERATURES NEAR +6C WILL SUPPORT
HIGHS REACHING THE LOWER TO MID 50S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE AND MID-LEVEL RIDGING WILL SHIFT OFF THE MID-
ATLANTIC AND NEW ENGLAND COASTS THROUGH SUNDAY BEFORE A SURFACE
TROUGH AND MID-LEVEL CLOSED LOW PASS SOUTH OF OUR FORECAST AREA ON
MONDAY. MODEL DIAGNOSTIC DISCUSSION REFERS TO HIGH CONFIDENCE WITH
THE STRENGTH AND PLACEMENT OF THIS CLOSED UPPER LOW AND ITS
ASSOCIATED EFFECT ON LOCAL SENSIBLE WEATHER. ANY SYNOPTIC LIFT AND
MOISTURE WORTH MENTIONING WILL BE COLLOCATED WITH THE LOW CENTER...
WELL TO OUR SOUTH...LEAVING WESTERN AND CENTRAL NEW YORK WITH FAIR
WEATHER THROUGH THE BEGINNING OF NEXT WEEK. MAINLY CLEAR SKIES WILL
PROMOTE PLENTY OF SUNSHINE SUNDAY AND MONDAY WITH ONLY A FEW HIGH
CLOUDS STREAMING NORTH FROM THE SOUTHERN SYSTEM ON MONDAY NIGHT.
SOUTHERLY FLOW AND 850MB TEMPS OF +8C WILL SUPPORT HIGHS REACHING
INTO THE LOWER TO MIDDLE 50S ON SUNDAY WITH UPPER 40S TO LOW 50S
EAST OF LAKE ONTARIO. THEN A NORTHERLY SHIFT TO THE WINDS AND COLD
ADVECTION ON MONDAY WILL KNOCK 850MB TEMPS BACK TOWARD 0C KEEPING
SURFACE HIGHS ABOUT 10F COOLER.
GOOD RADIATIONAL COOLING EACH NIGHT WILL ALLOW LOWS TO RANGE FROM
THE LOWER TO MIDDLE 30S NEAR THE LAKES TO THE UPPER 20S WELL INLAND.
LIGHT WINDS WILL ALLOW RIVER VALLEY FOG IN THE SOUTHERN TIER VALLEYS
WHICH COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE
TEMPS ALSO FALL BELOW FREEZING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A WAVY PACIFIC FLOW IS EXPECTED TO GENERALLY KEEP MILD TEMPERATURES
AND BENIGN WEATHER THROUGH NEXT WEEK. 04/12Z GFS AND ECMWF MODELS
ARE NOT WELL ALIGNED WITH THE 500MB PATTERN WITH EACH MODEL SHOWING
A DIFFERENCE IN TIMING AND LOCATION OF SUBTLE SHORTWAVE TROUGHS
MOVING ACROSS THE CONUS. THIS LEADS TO A LOW CONFIDENCE FORECAST FOR
MORE DEFINITIVE TIMING OF ANY MINOR PRECIPITATION EVENTS THAT MAY
IMPACT OUR FORECAST AREA.
IT APPEARS THAT A DEEPENING STORM OFF THE EAST COAST TUESDAY WILL
NOT BE A THREAT TO WESTERN AND CENTRAL NEW YORK AT THIS TIME
ALTHOUGH THE 04/12Z ECMWF HAS SHIFTED A BIT FURTHER NORTH WITH THE
TRACK OF THE CLOSED 500MB LOW. AFTER THIS THE FORECAST ONLY INCLUDES
SLIGHT CHANCE POPS FROM WEDNESDAY NIGHT INTO FRIDAY DUE TO THE POOR
MODEL AGREEMENT. DAYTIME TEMPERATURES WILL RUN ON THE MILD SIDE FOR
THIS TIME OF YEAR WITH OVERNIGHT LOWS CLOSER TO SEASONAL NORMALS.
HIGHS WILL RANGE FROM THE MID 40S TO AROUND 50 EACH DAY WITH
OVERNIGHT LOWS RANGING IN THE MID 30S NEAR THE LAKES TO UPPER 20S
INLAND.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
A WIDESPREAD STRATUS DECK WILL STUBBORNLY PERSIST THROUGH THE
MORNING WITH MOST LOCATIONS SEEING MVFR CIGS...BUT SOME IFR CIGS
ACROSS THE HIGHER ELEVATIONS OF THE SOUTHERN TIER AND THE TUG
HILL. CLEARING FROM WEST TO EAST SHOULD BE FAIRLY ROBUST
AFTER 17Z...WITH VFR CONDITIONS AND LIGHT WINDS BY MID TO LATE
AFTERNOON.
OUTLOOK...
SUNDAY TO WEDNESDAY...VFR.
&&
.MARINE...
HIGH PRESSURE WILL BUILD INTO THE LOWER LAKES THIS WEEKEND AND
REMAIN IN PLACE THROUGH THE MIDDLE OF NEXT WEEK...PROVIDING A RARE
EXTENDED STRETCH OF LIGHT WINDS AND FLAT WAVE ACTION ON THE LOWER
LAKES.
&&
.CLIMATE...
TEMPERATURES ACROSS WESTERN AND NORTH CENTRAL NEW YORK HAVE AVERAGED
WELL ABOVE NORMAL SINCE HALLOWEEN...LARGELY DUE TO A POWERFUL EL
NINO EVENT THAT IS IN PLACE OVER THE EQUATORIAL PACIFIC. THE
STRENGTH OF THE CURRENT EL NINO IS SIMILAR TO THE HISTORIC ONE FROM
1997-98 WHEN OUR REGION BASKED IN ONE OF THE MILDEST WINTERS OF THE
PAST SIXTY YEARS.
THE MILDER WEATHER DID HAVE AN IMPACT ON LAKE SNOWS THAT SEASON.
SNOWFALL FOR THAT PARTICULAR WINTER AVERAGED WELL BELOW NORMAL...
WITH LAKE EFFECT AREAS ONLY RECEIVING ABOUT HALF AS MUCH SNOW AS
USUAL. THE LACK OF SNOWFALL WAS NOT AS PERCEPTIBLE IN NON-LAKE
EFFECT AREAS THOUGH AS A FAVORABLE SYNOPTIC STORM TRACK ALLOWED FOR
NEAR NORMAL AMOUNTS...WITH THE FINGER LAKES REGION ACTUALLY
EXPERIENCING MORE SNOW THAN NORMAL.
DURING THE PAST SIX WEEKS...THERE HAVE BEEN TWO NOTICEABLE
HEMISPHERIC PATTERNS THAT HAVE SUPPORTED THE MILD WEATHER. THE
FIRST IS DIRECTLY RELATED TO STRONG EL NINOS...THAT BEING AN
ANOMALOUSLY STRONG ASIAN/NORTH PACIFIC JET. NOT ONLY IS THIS JET
STRONGER NORMAL BUT IS APPEARS TO BE DISPLACED SEVERAL HUNDRED
MILES FURTHER NORTH. THE EFFECTS OF THIS ARE TWO FOLD. IT
SUPPRESSES THE DEVELOPMENT OF A WEST COAST RIDGE...WHICH WAS
DOMINANT THE PAST TWO WINTERS...AND IT ALSO HELPS TO FLOOD THE
BULK OF NORTH AMERICA WITH PACIFIC MODIFIED AIR. WHILE KEEPING
PACIFIC BASED AIR IN PLACE...THIS PATTERN ALSO BLOCKS ANY ATTEMPT
AT ANY REAL COLD AIR FROM MAKING ITS WAY SOUTH. TRUE COLD AIR UP
TO THIS POINT HAS BEEN LOCKED IN PLACE BETWEEN THE CANADIAN
ARCHIPELAGO AND SIBERIA...OR POLEWARD OF 60N.
THE OTHER KEY HEMISPHERIC FEATURE HAS BEEN THE PERSISTENCE OF AN
ICELANDIC LOW. THIS PATTERN ENHANCES THE MID AND UPPER LEVEL JET AS
IT EXITS NORTH AMERICA...THUS KEEPING A STRONG LOW AMPLITUDE FLOW
ACROSS THE NORTH ATLANTIC. WITHOUT ANY HIGH LATITUDE BLOCKING (EX
GREENLAND BLOCK)...THE STRONG WEST TO EAST JET CAN REMAIN DOMINANT.
THE RESULT IS PERSISTENT `MILD` WEATHER ACROSS THE EASTERN HALF OF
NORTH AMERICA AS WELL AS EUROPE (POSITIVE NAO TRAIT).
MEDIUM AND LONG RANGE GUIDANCE CONTINUES TO KEEP THIS GENERAL
PATTERN IN PLACE FOR THE FORESEEABLE FUTURE...SO A CHANGE TO THE
GENERAL MILD PATTERN IS NOT ANTICIPATED THROUGH AT LEAST MID MONTH.
ANY COLD AIR THAT IS NEEDED FOR SIGNIFICANT LAKE EFFECT WOULD HAVE
TO BE `MANUFACTURED` LOCALLY...WHICH IS NOT SOMETHING THAT IS
TYPICALLY EXPERIENCED FOR MESOSCALE EVENTS SUCH AS LAKE EFFECT.
SUCH A PROCESS IS MORE FAVORABLE FOR LARGER SYNOPTIC SYSTEMS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH
AVIATION...TMA
MARINE...TMA
CLIMATE...RSH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
304 AM EST SAT DEC 5 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY WITH A GRADUAL
RETURN TO SUNSHINE AND ABOVE AVERAGE TEMPERATURES. THE CLEAR
SKIES AND WARM TEMPERATURES WILL CONTINUE SUNDAY AND RIGHT THROUGH
THE FIRST HALF OF NEXT WEEK AS HIGH PRESSURE REMAINS IN CONTROL.
&&
.NEAR TERM /THROUGH TONIGHT/...
A WIDESPREAD LOW STRATUS DECK LODGED UNDERNEATH A STEEP
SUBSIDENCE INVERSION WITHIN THE BACKGROUND OF WEAK SURFACE RIDGING
CONTINUING TO ENCOMPASSING MUCH OF WESTERN NEW YORK. 1000-975 MB
MOISTURE FIELDS ON THE HRRR AND RAP CONCUR WITH THE CURRENT
PLACEMENT OF THIS CLOUD DECK. CLOUDS WILL BE STUBBORN TO CLEAR
WITH CURRENT TRENDS POINTING TOWARD TAKING A DECIDEDLY MORE
PESSIMISTIC OUTLOOK ON CLOUD COVER NEARLY AREAWIDE THROUGH THE
MORNING PERIOD. ELEMENT OF SHALLOW FOG WITHIN THIS NEAR SURFACE
MOISTURE PLUME AS WELL.
STRATUS/FOG SHOULD ERODE FOR THE MOST PART BY AFTERNOON...ALTHOUGH
COULD CONTINUE TO LINGER ACROSS INTERIOR SECTIONS EAST OF LAKE
ONTARIO. INCREASING SUNSHINE ALONG WITH DEVELOPING WARM AIR
ADVECTION PATTERN SHOULD GET AFTERNOON TEMPERATURES IN THE LOWER
50S ON THE LAKE PLAINS OF WESTERN NEW YORK AND MID TO UPPER 40S
ACROSS HIGHER TERRAIN AND THE EASTERN LAKE ONTARIO REGION.
BY SUNDAY...SURFACE HIGH PRESSURE AND MID LEVEL RIDGING WILL SHIFT
OFF THE MID-ATLANTIC AND NEW ENGLAND COASTS. AMPLE SUNSHINE ALONG
WITH A SOUTHERLY FLOW AND 850 MB TEMPERATURES NEAR +6C WILL SUPPORT
HIGHS REACHING THE LOWER TO MID 50S.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE AND MID-LEVEL RIDGING WILL SHIFT OFF THE MID-
ATLANTIC AND NEW ENGLAND COASTS THROUGH SUNDAY BEFORE A SURFACE
TROUGH AND MID-LEVEL CLOSED LOW PASS SOUTH OF OUR FORECAST AREA ON
MONDAY. MODEL DIAGNOSTIC DISCUSSION REFERS TO HIGH CONFIDENCE WITH
THE STRENGTH AND PLACEMENT OF THIS CLOSED UPPER LOW AND ITS
ASSOCIATED EFFECT ON LOCAL SENSIBLE WEATHER. ANY SYNOPTIC LIFT AND
MOISTURE WORTH MENTIONING WILL BE COLLOCATED WITH THE LOW CENTER...
WELL TO OUR SOUTH...LEAVING WESTERN AND CENTRAL NEW YORK WITH FAIR
WEATHER THROUGH THE BEGINNING OF NEXT WEEK. MAINLY CLEAR SKIES WILL
PROMOTE PLENTY OF SUNSHINE SUNDAY AND MONDAY WITH ONLY A FEW HIGH
CLOUDS STREAMING NORTH FROM THE SOUTHERN SYSTEM ON MONDAY NIGHT.
SOUTHERLY FLOW AND 850MB TEMPS OF +8C WILL SUPPORT HIGHS REACHING
INTO THE LOWER TO MIDDLE 50S ON SUNDAY WITH UPPER 40S TO LOW 50S
EAST OF LAKE ONTARIO. THEN A NORTHERLY SHIFT TO THE WINDS AND COLD
ADVECTION ON MONDAY WILL KNOCK 850MB TEMPS BACK TOWARD 0C KEEPING
SURFACE HIGHS ABOUT 10F COOLER.
GOOD RADIATIONAL COOLING EACH NIGHT WILL ALLOW LOWS TO RANGE FROM
THE LOWER TO MIDDLE 30S NEAR THE LAKES TO THE UPPER 20S WELL INLAND.
LIGHT WINDS WILL ALLOW RIVER VALLEY FOG IN THE SOUTHERN TIER VALLEYS
WHICH COULD MAKE FOR SOME SLICK ROADWAYS IN AREAS WHERE SURFACE
TEMPS ALSO FALL BELOW FREEZING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A WAVY PACIFIC FLOW IS EXPECTED TO GENERALLY KEEP MILD TEMPERATURES
AND BENIGN WEATHER THROUGH NEXT WEEK. 04/12Z GFS AND ECMWF MODELS
ARE NOT WELL ALIGNED WITH THE 500MB PATTERN WITH EACH MODEL SHOWING
A DIFFERENCE IN TIMING AND LOCATION OF SUBTLE SHORTWAVE TROUGHS
MOVING ACROSS THE CONUS. THIS LEADS TO A LOW CONFIDENCE FORECAST FOR
MORE DEFINITIVE TIMING OF ANY MINOR PRECIPITATION EVENTS THAT MAY
IMPACT OUR FORECAST AREA.
IT APPEARS THAT A DEEPENING STORM OFF THE EAST COAST TUESDAY WILL
NOT BE A THREAT TO WESTERN AND CENTRAL NEW YORK AT THIS TIME
ALTHOUGH THE 04/12Z ECMWF HAS SHIFTED A BIT FURTHER NORTH WITH THE
TRACK OF THE CLOSED 500MB LOW. AFTER THIS THE FORECAST ONLY INCLUDES
SLIGHT CHANCE POPS FROM WEDNESDAY NIGHT INTO FRIDAY DUE TO THE POOR
MODEL AGREEMENT. DAYTIME TEMPERATURES WILL RUN ON THE MILD SIDE FOR
THIS TIME OF YEAR WITH OVERNIGHT LOWS CLOSER TO SEASONAL NORMALS.
HIGHS WILL RANGE FROM THE MID 40S TO AROUND 50 EACH DAY WITH
OVERNIGHT LOWS RANGING IN THE MID 30S NEAR THE LAKES TO UPPER 20S
INLAND.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
WIDESPREAD STRATUS DECK WILL STUBBORNLY PERSIST WITH MOST
LOCATIONS SEEING MVFR CIGS...BUT SOME IFR CIGS ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHERN TIER AND THE TUG HILL. EXPECT MAINLY
STATUS QUO THROUGH THE EARLY MORNING...EXCEPT FOR MAYBE CIGS
LOWERING OF ANOTHER 500 FEET OR SO. IN ADDITION... LOCATIONS
ACROSS THE SOUTHERN TIER MAY START TO SEE IFR VSBY RESTRICTIONS
AS THE STRATUS DECK LOWERS CLOSER TO THE HIGH TERRAIN.
CLEARING FROM WEST TO EAST SHOULD BE FAIRLY ROBUST SATURDAY
MORNING...WITH VFR CONDITIONS AND LIGHT WINDS PREDOMINATE BY
AFTERNOON.
OUTLOOK...
SUNDAY TO WEDNESDAY...VFR.
&&
.MARINE...
HIGH PRESSURE WILL BUILD INTO THE LOWER LAKES THIS WEEKEND AND
REMAIN IN PLACE THROUGH THE MIDDLE OF NEXT WEEK...PROVIDING A RARE
EXTENDED STRETCH OF LIGHT WINDS AND FLAT WAVE ACTION ON THE LOWER
LAKES.
&&
.CLIMATE...
TEMPERATURES ACROSS WESTERN AND NORTH CENTRAL NEW YORK HAVE AVERAGED
WELL ABOVE NORMAL SINCE HALLOWEEN...LARGELY DUE TO A POWERFUL EL
NINO EVENT THAT IS IN PLACE OVER THE EQUATORIAL PACIFIC. THE
STRENGTH OF THE CURRENT EL NINO IS SIMILAR TO THE HISTORIC ONE FROM
1997-98 WHEN OUR REGION BASKED IN ONE OF THE MILDEST WINTERS OF THE
PAST SIXTY YEARS.
THE MILDER WEATHER DID HAVE AN IMPACT ON LAKE SNOWS THAT SEASON.
SNOWFALL FOR THAT PARTICULAR WINTER AVERAGED WELL BELOW NORMAL...
WITH LAKE EFFECT AREAS ONLY RECEIVING ABOUT HALF AS MUCH SNOW AS
USUAL. THE LACK OF SNOWFALL WAS NOT AS PERCEPTIBLE IN NON-LAKE
EFFECT AREAS THOUGH AS A FAVORABLE SYNOPTIC STORM TRACK ALLOWED FOR
NEAR NORMAL AMOUNTS...WITH THE FINGER LAKES REGION ACTUALLY
EXPERIENCING MORE SNOW THAN NORMAL.
DURING THE PAST SIX WEEKS...THERE HAVE BEEN TWO NOTICEABLE
HEMISPHERIC PATTERNS THAT HAVE SUPPORTED THE MILD WEATHER. THE
FIRST IS DIRECTLY RELATED TO STRONG EL NINOS...THAT BEING AN
ANOMALOUSLY STRONG ASIAN/NORTH PACIFIC JET. NOT ONLY IS THIS JET
STRONGER NORMAL BUT IS APPEARS TO BE DISPLACED SEVERAL HUNDRED
MILES FURTHER NORTH. THE EFFECTS OF THIS ARE TWO FOLD. IT
SUPPRESSES THE DEVELOPMENT OF A WEST COAST RIDGE...WHICH WAS
DOMINANT THE PAST TWO WINTERS...AND IT ALSO HELPS TO FLOOD THE
BULK OF NORTH AMERICA WITH PACIFIC MODIFIED AIR. WHILE KEEPING
PACIFIC BASED AIR IN PLACE...THIS PATTERN ALSO BLOCKS ANY ATTEMPT
AT ANY REAL COLD AIR FROM MAKING ITS WAY SOUTH. TRUE COLD AIR UP
TO THIS POINT HAS BEEN LOCKED IN PLACE BETWEEN THE CANADIAN
ARCHIPELAGO AND SIBERIA...OR POLEWARD OF 60N.
THE OTHER KEY HEMISPHERIC FEATURE HAS BEEN THE PERSISTENCE OF AN
ICELANDIC LOW. THIS PATTERN ENHANCES THE MID AND UPPER LEVEL JET AS
IT EXITS NORTH AMERICA...THUS KEEPING A STRONG LOW AMPLITUDE FLOW
ACROSS THE NORTH ATLANTIC. WITHOUT ANY HIGH LATITUDE BLOCKING (EX
GREENLAND BLOCK)...THE STRONG WEST TO EAST JET CAN REMAIN DOMINANT.
THE RESULT IS PERSISTENT `MILD` WEATHER ACROSS THE EASTERN HALF OF
NORTH AMERICA AS WELL AS EUROPE (POSITIVE NAO TRAIT).
MEDIUM AND LONG RANGE GUIDANCE CONTINUES TO KEEP THIS GENERAL
PATTERN IN PLACE FOR THE FORESEEABLE FUTURE...SO A CHANGE TO THE
GENERAL MILD PATTERN IS NOT ANTICIPATED THROUGH AT LEAST MID MONTH.
ANY COLD AIR THAT IS NEEDED FOR SIGNIFICANT LAKE EFFECT WOULD HAVE
TO BE `MANUFACTURED` LOCALLY...WHICH IS NOT SOMETHING THAT IS
TYPICALLY EXPERIENCED FOR MESOSCALE EVENTS SUCH AS LAKE EFFECT.
SUCH A PROCESS IS MORE FAVORABLE FOR LARGER SYNOPTIC SYSTEMS.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMA
NEAR TERM...TMA
SHORT TERM...WCH
LONG TERM...SMITH
AVIATION...TMA
MARINE...TMA
CLIMATE...RSH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
828 PM EST SUN DEC 6 2015
.SYNOPSIS...
A COASTAL TROUGH WILL DEVELOP OFFSHORE AND SPREAD LIGHT RAIN OVER
THE AREA LATE TONIGHT AND MONDAY. LOW PRESSURE WILL DEVELOP ON
THE TROUGH MONDAY AND MOVE SLOWLY NORTHEAST. HIGH PRESSURE WILL
BRING BACK SUNSHINE AND SEASONABLE TEMPERATURES BEGINNING TUESDAY.
TEMPERATURES SHOULD RISE WELL ABOVE NORMAL BY NEXT WEEKEND AS THE
REGION REMAINS UNDER THE CONTROL OF HIGH PRESSURE.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 828 PM SUNDAY...00Z CHS RAOB INDICATES THAT MOISTURE HAS
BEGUN TO INCREASE ACROSS COASTAL SOUTH CAROLINA AS PRECIPITABLE
WATER VALUES HAVE INCREASED TO 0.93 INCHES. THIS TREND WILL
CONTINUE OVERNIGHT AS MOISTURE ASSOCIATED WITH CONVECTION OFF THE
COAST OF GEORGIA GETS DRAWN NORTHWARD AHEAD OF THE MID-LEVEL LOW
SLIDING EAST ACROSS INDIANA AND OHIO. WITH A SURFACE HIGH IN PLACE
ACROSS THE CAROLINA PIEDMONT...THIS MOISTURE WILL OVERRUN LOW-
LEVEL NORTHEASTERLY FLOW AND IN ADDITION TO CLOUDS...LEAD TO
INCREASING CHANCES OF LIGHT RAIN FROM SOUTH TO NORTH AFTER
MIDNIGHT. MAY HAVE TO MAKE SOME ADJUSTMENTS TO TIMING OF POP
VALUES AS IT MAY BE DIFFICULT TO GET MEASURABLE PRECIP AS FAR
NORTH AS THE CAPE FEAR REGION BY DAYBREAK MONDAY.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...WEAK SURFACE WAVE DEVELOPING ALONG COASTAL
TROUGH WILL SPREAD RAIN OVER THE AREA MON. PRECIP IS LIKELY TO BE
ONGOING ALONG THE COAST AS THE PERIOD BEGINS. ISENTROPIC LIFT IS
LIMITED AND THERE REMAINS AN APPRECIABLE AMOUNT OF DRY AIR INLAND
FROM THE COAST. AS SUCH THE PRECIP SHIELD IS EXPECTED TO BE RATHER
SMALL AND MAY NOT EXTEND BEYOND THE WESTERN EDGE OF THE FORECAST
AREA. MID LEVEL FORCING DOES INCREASE DUE TO DIVERGENCE ALOFT
ASSOCIATED WITH 5H SHORTWAVE MOVING INTO THE MID ATLANTIC REGION
DURING MON. THIS COULD BRING ABOUT AN INCREASE IN COVERAGE AND
INTENSITY...MAINLY FOR THE LATE MORNING TO EARLY AFTERNOON HOURS AND
ALONG THE NC COAST. BY EVENING THE SHORTWAVE WILL HAVE LIFTED THE
DEVELOPING LOW/TROUGH COMBO AND ANY ASSOCIATED RAINFALL OFF TO THE
NORTHEAST.
WEAK SURFACE HIGH AND MID LEVEL SUBSIDENCE WORK TO DRY THE REGION
OUT MON NIGHT. NATURE OF HIGH LIMITS COLD ADVECTION AND WITH THE
EXIT OF THE SHORTWAVE HEIGHTS AND THICKNESS WILL ACTUALLY CREEP UP A
LITTLE OVERNIGHT. PROGRESSIVE FLOW MON NIGHT THROUGH TUE NIGHT WILL
KEEP THE REGION DRY. MID LEVEL FLOW STARTS TO BECOME MORE
SOUTHWESTERLY LATE TUE NIGHT AS THE NEXT SHORTWAVE MOVES INTO THE MS
VALLEY. OTHER THAN A POTENTIAL INCREASE IN MID AND HIGH CLOUD COVER
TUE NIGHT THIS FEATURE WILL HAVE NO IMPACT ON THE REGION DURING THE
PERIOD.
CLOUD COVER AND RAIN ALONG WITH NORTHEAST FLOW WILL KEEP
TEMPERATURES BELOW CLIMO MON BUT TEMPERATURES NEAR CLIMO ARE
EXPECTED MON NIGHT. ABUNDANT SUNSHINE AND WESTERLY FLOW ALOFT WILL
LEAD TO TEMPERATURES NEAR CLIMO TUE AND BOUNDARY LAYER FLOW WILL
HELP KEEP LOWS NEAR CLIMO TUE NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...VERALL EXPECT A DRY FORECAST PERIOD AS HIGH
PRESSURE EASTWARD MIGRATES ACROSS THE REGION THROUGH THE WEEK. A
VERY PROGRESSIVE MORE ZONAL FLOW INITIALLY...PLAGUED BY NORTHERN
STREAM SHORTWAVES BECOMES MORE AMPLIFIED HEADING INTO THE WEEKEND
WITH A RIDGE BUILDING UP THROUGH THE SOUTHEAST. THE SHORTWAVES MAY
PRODUCE SOME PERIODS OF CLOUDS BUT OVERALL EXPECT MAINLY CLEAR TO
PARTLY CLOUDY SKIES. AS THE SFC HIGH SHIFTS OFF SHORE LATE WED INTO
THURS A GENERALLY DEEPER S-SW RETURN FLOW WILL SET UP.
THE MID TO UPPER RIDGE SHIFTS SLOWLY EAST FINALLY MAKING IT OFF
SHORE EARLY NEXT WEEK. PREVIOUS FORECAST SHIFTED RIDGE EAST FASTER
ALLOWING FOR A WETTER FORECAST OVER THE LATTER HALF OF THE
WEEKEND...BUT NOW IT LOOKS LIKE SOUTHERN STREAM LOW MAY RIDE UP WEST
OF THE AREA AND MAY NOT AFFECT COASTAL CAROLINAS UNTIL MONDAY INTO
TUES.
TEMPS WILL GENERALLY RUN ABOVE NORMAL AIDED BY A WESTERLY FLOW ALOFT
AND RIDGING ALOFT PLUS A WARMER AND MOISTER RETURN FLOW HEADING INTO
THE WEEKEND.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...WATER VAPOR AND UPPER LEVEL LOW ARE STILL FORECAST TO
SHIFT ACROSS THE TAF SITES THROUGH THIS PERIOD. THE HRRR CONTINUES
TO SHOW ALL LOCATIONS TO SEE MVFR VISIBILITIES WITH LARGE SWATH
OF RAIN MOVING IN FROM THE SOUTH GENERALLY AFTER 06 UTC AND
CONTINUING THROUGH THE REMAINDER OF THE TAF FORECAST PERIOD.
CEILING ARE EXPECTED TO BECOME IFR AT THE COASTAL TAF SITES AND
MVFR AT KFLO AND KLBT.
EXTENDED AVIATION OUTLOOK...POTENTIAL FOR RESTRICTIONS TO DEVELOP
ON MONDAY WITH LOW CLOUDS AND SHOWERS. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 828 PM SUNDAY...AREA BUOY OBS SHOW THE 5-6 FT SWELL EVERY 9
SECONDS PERSISTS ACROSS THE OUTER PORTIONS OF THE MARINE
ZONES...15 TO 20 NM FROM SHORE. THE TREND WILL BE FOR SEAS TO
SUBSIDE BELOW SMALL CRAFT ADVISORY CRITERIA AFTER MIDNIGHT AND
EXPECT TO BE ABLE TO ALLOW THE SCA TO EXPIRE ON SCHEDULE. THE
CENTER OF HIGH PRESSURE IN PLACE ACROSS THE INTERIOR CAROLINAS
THROUGH THE REMAINDER OF THE NIGHT WILL RESULT IN CONTINUED
NORTHEAST WINDS AROUND 10-15 KNOTS.
A LINE OF LIGHT SHOWERS OFF THE SOUTH CAROLINA COAST WILL
EVENTUALLY WORK INTO THE SOUTHERN WATERS OVER THE NEXT FEW HOURS.
THE ACTIVITY WILL EVENTUALLY BE DRAWN NORTHWARD BUT DO NOT EXPECT
SIGNIFICANT RAINFALL TO SPREAD NORTH OF LITTLE RIVER INLET BEFORE
DAWN.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...PINCHED GRADIENT MON AND MON NIGHT WILL MAINTAIN
ELEVATED NORTH TO NORTHEAST FLOW AS COASTAL LOW/TROUGH COMBO LIFT
NORTHEAST. HIGH PRESSURE STARTS TO BUILD IN FROM THE WEST LATE MON
NIGHT WITH WINDS VEERING BACK TO NORTHEAST FOR TUE. SURFACE HIGH IS
WEAK AND PRESSURE GRADIENT IS ILL DEFINED. THUS NORTHEAST WINDS TUE
AND TUE NIGHT WILL BE UNDER 10 KT WITH WINDS DIPPING UNDER 5 KT AND
BECOMING HIGHLY VARIABLE LATE TUE NIGHT. PINCHED GRADIENT AND
RESULTING ELEVATED NORTHEAST FLOW MON AND MON NIGHT WILL KEEP SEAS 3
TO 5 FT INTO TUE. DECREASE IN WINDS TUE AND TUE NIGHT QUICKLY ALLOWS
SEAS TO DROP WITH 2 TO 4 FT EXPECTED TUE AND 1 TO 3 FT TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...HIGH PRESSURE WILL BE MIGRATING SLOWLY EAST
THROUGH THE PERIOD WITH A FAINT HINT OF A WEAK TROUGH WED NIGHT.
OVERALL WEAK GRADIENT WILL KEEP LIGHTER AND MORE VARIABLE WINDS ON
BEFORE HIGH SHIFTS FARTHER EAST AND A RETURN FLOW SETS UP LASTING
INTO THE WEEKEND. A COUPLE OF SHORTWAVES MAY KICK UP WINDS FROM TIME
TO TIME BUT OVERALL EXPECT BENIGN WINDS AND SEAS...MAINLY LESS THAN
3 FT...MIXING WITH A LONGER PERIOD UP TO 9 SEC E-SE SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...CRM
SHORT TERM...III
LONG TERM...RGZ
AVIATION...DRH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
724 PM EST SUN DEC 6 2015
.SYNOPSIS...
A COASTAL TROUGH WILL DEVELOP OFFSHORE AND SPREAD LIGHT RAIN OVER
THE AREA LATE TONIGHT AND MONDAY. LOW PRESSURE WILL DEVELOP ON
THE TROUGH MONDAY AND MOVE SLOWLY NORTHEAST. HIGH PRESSURE WILL
BRING BACK SUNSHINE AND SEASONABLE TEMPERATURES BEGINNING TUESDAY.
TEMPERATURES SHOULD RISE WELL ABOVE NORMAL BY NEXT WEEKEND AS THE
REGION REMAINS UNDER THE CONTROL OF HIGH PRESSURE.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 3 PM SUNDAY...CLOUDS WERE FILLING IN ACROSS SOUTHERN
PORTIONS OF THE FORECAST AREA AND THIS TREND WILL PERSIST WHILE
EXPANDING NORTHWARD THROUGH THIS EVE. SKIES WILL BE CLOUDY
THROUGHOUT OVERNIGHT. LIGHT RAIN SHOULD BEGIN TO DEVELOP FROM N TO
S OVERNIGHT AND MON MORNING...MOST PREVALENT ALONG THE COAST.
A COASTAL TROUGH IS EXPECTED TO FORM OFFSHORE LATE TONIGHT. AS
THE FLOW NEAR THE SURFACE REMAINS MORE ONSHORE...THE FLOW ALOFT
WILL INCREASE FROM THE SOUTHWEST. THIS WILL HELP TO DRAW IN
ATLANTIC MOISTURE IN THE LOW LEVELS. HOWEVER...THE DEPTH OF
MOISTURE WILL NOT BE THAT DEEP...ABOUT 15 KFT. A POTENT MID-LEVEL
SHORTWAVE...ROTATING AROUND AN UPPER LOW...MOVING ACROSS THE
SOUTHERN GREAT LAKES AND MID-WEST...WILL BE APPROACHING FROM THE
NW LATE TONIGHT. MOISTURE ADVECTION AND LIFT SHOULD BE ENOUGH FOR
THE DEVELOPMENT OF LIGHT RAIN LATE TONIGHT AND MONDAY. THE RAIN
SHOULD DEVELOP FIRST ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA
AND THEN EXPAND NORTHWARD TOWARD MORNING. RAINFALL MAY NOT REACH
SOME LOCATIONS WEST OF I-95 AND WILL SHOW LOWEST POPS HERE.
CLOUDS TONIGHT WILL ALLOW FOR ABOVE NORMAL TEMPS...LOW AND MID 40S.
LOWS IN THE UPPER 40S ARE EXPECTED AT THE BEACHES.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...WEAK SURFACE WAVE DEVELOPING ALONG COASTAL
TROUGH WILL SPREAD RAIN OVER THE AREA MON. PRECIP IS LIKELY TO BE
ONGOING ALONG THE COAST AS THE PERIOD BEGINS. ISENTROPIC LIFT IS
LIMITED AND THERE REMAINS AN APPRECIABLE AMOUNT OF DRY AIR INLAND
FROM THE COAST. AS SUCH THE PRECIP SHIELD IS EXPECTED TO BE RATHER
SMALL AND MAY NOT EXTEND BEYOND THE WESTERN EDGE OF THE FORECAST
AREA. MID LEVEL FORCING DOES INCREASE DUE TO DIVERGENCE ALOFT
ASSOCIATED WITH 5H SHORTWAVE MOVING INTO THE MID ATLANTIC REGION
DURING MON. THIS COULD BRING ABOUT AN INCREASE IN COVERAGE AND
INTENSITY...MAINLY FOR THE LATE MORNING TO EARLY AFTERNOON HOURS AND
ALONG THE NC COAST. BY EVENING THE SHORTWAVE WILL HAVE LIFTED THE
DEVELOPING LOW/TROUGH COMBO AND ANY ASSOCIATED RAINFALL OFF TO THE
NORTHEAST.
WEAK SURFACE HIGH AND MID LEVEL SUBSIDENCE WORK TO DRY THE REGION
OUT MON NIGHT. NATURE OF HIGH LIMITS COLD ADVECTION AND WITH THE
EXIT OF THE SHORTWAVE HEIGHTS AND THICKNESS WILL ACTUALLY CREEP UP A
LITTLE OVERNIGHT. PROGRESSIVE FLOW MON NIGHT THROUGH TUE NIGHT WILL
KEEP THE REGION DRY. MID LEVEL FLOW STARTS TO BECOME MORE
SOUTHWESTERLY LATE TUE NIGHT AS THE NEXT SHORTWAVE MOVES INTO THE MS
VALLEY. OTHER THAN A POTENTIAL INCREASE IN MID AND HIGH CLOUD COVER
TUE NIGHT THIS FEATURE WILL HAVE NO IMPACT ON THE REGION DURING THE
PERIOD.
CLOUD COVER AND RAIN ALONG WITH NORTHEAST FLOW WILL KEEP
TEMPERATURES BELOW CLIMO MON BUT TEMPERATURES NEAR CLIMO ARE
EXPECTED MON NIGHT. ABUNDANT SUNSHINE AND WESTERLY FLOW ALOFT WILL
LEAD TO TEMPERATURES NEAR CLIMO TUE AND BOUNDARY LAYER FLOW WILL
HELP KEEP LOWS NEAR CLIMO TUE NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...VERALL EXPECT A DRY FORECAST PERIOD AS HIGH
PRESSURE EASTWARD MIGRATES ACROSS THE REGION THROUGH THE WEEK. A
VERY PROGRESSIVE MORE ZONAL FLOW INITIALLY...PLAGUED BY NORTHERN
STREAM SHORTWAVES BECOMES MORE AMPLIFIED HEADING INTO THE WEEKEND
WITH A RIDGE BUILDING UP THROUGH THE SOUTHEAST. THE SHORTWAVES MAY
PRODUCE SOME PERIODS OF CLOUDS BUT OVERALL EXPECT MAINLY CLEAR TO
PARTLY CLOUDY SKIES. AS THE SFC HIGH SHIFTS OFF SHORE LATE WED INTO
THURS A GENERALLY DEEPER S-SW RETURN FLOW WILL SET UP.
THE MID TO UPPER RIDGE SHIFTS SLOWLY EAST FINALLY MAKING IT OFF
SHORE EARLY NEXT WEEK. PREVIOUS FORECAST SHIFTED RIDGE EAST FASTER
ALLOWING FOR A WETTER FORECAST OVER THE LATTER HALF OF THE
WEEKEND...BUT NOW IT LOOKS LIKE SOUTHERN STREAM LOW MAY RIDE UP WEST
OF THE AREA AND MAY NOT AFFECT COASTAL CAROLINAS UNTIL MONDAY INTO
TUES.
TEMPS WILL GENERALLY RUN ABOVE NORMAL AIDED BY A WESTERLY FLOW ALOFT
AND RIDGING ALOFT PLUS A WARMER AND MOISTER RETURN FLOW HEADING INTO
THE WEEKEND.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...WATER VAPOR AND UPPER LEVEL LOW ARE STILL FORECAST TO
SHIFT ACROSS THE TAF SITES THROUGH THIS PERIOD. THE HRRR CONTINUES
TO SHOW ALL LOCATIONS TO SEE MVFR VISIBILITIES WITH LARGE SWATH
OF RAIN MOVING IN FROM THE SOUTH GENERALLY AFTER 06 UTC AND
CONTINUING THROUGH THE REMAINDER OF THE TAF FORECAST PERIOD.
CEILING ARE EXPECTED TO BECOME IFR AT THE COASTAL TAF SITES AND
MVFR AT KFLO AND KLBT.
EXTENDED AVIATION OUTLOOK...POTENTIAL FOR RESTRICTIONS TO DEVELOP
ON MONDAY WITH LOW CLOUDS AND SHOWERS. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM SUNDAY...A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH
THIS EVE. A 9 SECOND EASTERLY SWELL IS EXPECTED TO KEEP SEAS
ELEVATED AND THUS WILL NEED TO HOLD ONTO SMALL CRAFT ADVISORY
FLAGS THROUGH MIDNIGHT. SEAS WILL BE UP TO 6 FT ACROSS THE MORE
OUTER WATERS AND 4 TO 5 FT ELSEWHERE. SEAS WILL ONLY SUBSIDE
SLIGHTLY OVERNIGHT AS WIND AND SWELL ENERGY DIMINISH. WIND SPEEDS
UP TO 15 TO 20 KT THIS EVE WILL DIMINISH TO 10 TO 15 KT
THROUGHOUT. THE RIDGE OF HIGH PRESSURE WILL WEAKEN SIGNIFICANTLY
TONIGHT. HOWEVER...A DEVELOPING OFFSHORE COASTAL TROUGH WILL SERVE
TO KEEP THE PRESSURE GRADIENT FROM RELAXING FURTHER. RAIN IS
EXPECTED TO DEVELOP ACROSS THE WATERS OVERNIGHT.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...PINCHED GRADIENT MON AND MON NIGHT WILL MAINTAIN
ELEVATED NORTH TO NORTHEAST FLOW AS COASTAL LOW/TROUGH COMBO LIFT
NORTHEAST. HIGH PRESSURE STARTS TO BUILD IN FROM THE WEST LATE MON
NIGHT WITH WINDS VEERING BACK TO NORTHEAST FOR TUE. SURFACE HIGH IS
WEAK AND PRESSURE GRADIENT IS ILL DEFINED. THUS NORTHEAST WINDS TUE
AND TUE NIGHT WILL BE UNDER 10 KT WITH WINDS DIPPING UNDER 5 KT AND
BECOMING HIGHLY VARIABLE LATE TUE NIGHT. PINCHED GRADIENT AND
RESULTING ELEVATED NORTHEAST FLOW MON AND MON NIGHT WILL KEEP SEAS 3
TO 5 FT INTO TUE. DECREASE IN WINDS TUE AND TUE NIGHT QUICKLY ALLOWS
SEAS TO DROP WITH 2 TO 4 FT EXPECTED TUE AND 1 TO 3 FT TUE NIGHT.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...HIGH PRESSURE WILL BE MIGRATING SLOWLY EAST
THROUGH THE PERIOD WITH A FAINT HINT OF A WEAK TROUGH WED NIGHT.
OVERALL WEAK GRADIENT WILL KEEP LIGHTER AND MORE VARIABLE WINDS ON
BEFORE HIGH SHIFTS FARTHER EAST AND A RETURN FLOW SETS UP LASTING
INTO THE WEEKEND. A COUPLE OF SHORTWAVES MAY KICK UP WINDS FROM TIME
TO TIME BUT OVERALL EXPECT BENIGN WINDS AND SEAS...MAINLY LESS THAN
3 FT...MIXING WITH A LONGER PERIOD UP TO 9 SEC E-SE SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR AMZ250-252-
254-256.
&&
$$
NEAR TERM...RJD
SHORT TERM...III
LONG TERM...RGZ
AVIATION...DRH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
703 PM CST SUN DEC 6 2015
.UPDATE...
ISSUED AT 659 PM CST SUN DEC 6 2015
CIRRUS WILL INCREASE TONIGHT AND A SOUTH WIND WILL STAY IN THE 8
TO 15 KT RANGE IN THE RRV AND ERN ND. THIS WILL HELP KEEP TEMPS
FROM FALLING AS LOW AS LAST NIGHT. AFTER A QUICK FALL THIS EARLY
EVE DO EXPECT A MORE STABLE TEMP PATTERN OVERNIGHT. ONE THING TO
WATCH IS WILL LOW CLOUDS AND FOG CURRENTLY BRAINERD TO LONG
PRAIRIE TO SAUK CENTRE RETURN NORTH AS SFC FLOW BECOMES A BIT MORE
SOUTH-SOUTHEAST. IT WOULD ONLY IMPACT FAR SOUTHEASTERN FCST AREA
WADENA-HUBBARD-EASTERN OTTER TAIL AND MAYBE SOUTHERN BELTRAMI COUNTY.
SOMETHING TO WATCH.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM CST SUN DEC 6 2015
THE MAIN CHALLENGE WILL BE TEMPS AND QPF CHANCES TUE INTO TUE
NIGHT. MODELS ARE IN FAIRLY GOOD AGREEMENT...WITH SOME TIMING AND
PLACEMENT ISSUES WITH QPF TUE/TUE NIGHT. WE PREFER THE GFS THAT
HAS A DECENT HANDLE ON CURRENT SET UP.
FOR TONIGHT...SOUTHERLY WINDS SHOULD REMAIN NEAR 10KT FOR ALL BUT
THE FAR EAST. THE HRRR INDICATES SOME FOG ONCE AGAIN IN THE FAR
EAST SO WILL ADD. TEMPS WILL CONTINUE WELL ABOVE NORMAL.
ON MONDAY...ANOTHER VERY MILD DAY WITH WESTERLY FLOW ONCE AGAIN.
TEMPS SHOULD BE SIMILAR TO TODAY AND MAY EVEN BE A BIT WARMER WITH
MORE WESTERLY WINDS NEAR THE SFC.
FOR MONDAY NIGHT...CLOUDS WILL INCREASE IN THE WEST LATE AND WINDS
SHOULD REMAIN MIXED ENOUGH TO KEEP TEMPS NEAR 30.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM CST SUN DEC 6 2015
FOR TUE...A SHORTWAVE MOVES THROUGH WITH SOME RAIN...FREEZING RAIN
EARLY TRANSITIONING TO RAIN FAIRLY QUICKLY. THE GFS HAS SOME QPF
SOUTH WITH THE NAM FURTHER NORTH...WITH THE ECMWF MORE
BROADBRUSHED QPF.
ON TUE NIGHT...ANY PRECIP WILL MOVE INTO THE EAST. IT SHOULD BE
MAINLY RAIN THAT COULD MIX WITH A FEW FLAKES BEFORE ENDING.
ON WED...MORE VERY WARM CHINOOK MODIFIED AIR MOVES IN. TEMPS
SHOULD BE INTO THE 40S PERHAPS EVEN WARMER FOR AREAS THAT HAVE NO
SNOW.
FOR WEDNESDAY NIGHT THROUGH SUNDAY...MODELS DEPICT A MUDDY ZONAL
FLOW PATTERN THROUGH THE MIDWEEK PERIOD WITH A TRANSITION TO A
DEEP CENTRAL CONUS TROF FOR THE WEEKEND. THUS WILL EXPECT
SEASONABLY MILD CONDITIONS AND PERIODS OF LIGHT RAIN CHANGING TO
SNOW LATE ON THURSDAY... WITH A TURN TO SOMEWHAT COOLER CONDITIONS
AND A GREATER CHANCE FOR WIDEPSREAD LIGHT SNOW FROM LATE FRIDAY
INTO SUNDAY. SNOWFALL AMOUNTS ARE STILL EXPECTED TO REMAIN SCANT
AT LEAST THROUGH SATURDAY... SO NET IMPACTS OF THE EXPECTED LIGHT
SNOW ON OVERALL TEMPERATURE PATTERNS SHOULD BE SLIGHT. THUS WILL
CONTINUE TO BUMP TEMPERATURES AROUND 10 DEGREES ABOVE LONG TERM
NORMALS YET ON SATURDAY /EXPECTED HIGHS NEAR THE FREEZING POINT/
AND AROUND 5 DEGREES ABOVE NORMAL ON SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 659 PM CST SUN DEC 6 2015
ONLY TAF SITE TO WATCH IS BEMIDJI AND WILL ANY FOG FORM OR MOVE
BACK IN FROM THE SOUTH OVERNIGHT AS WINDS BECOME A BIT MORE
SOUTHERLY 5-10KT RANGE. HRRR KEEPS IT JUST SOUTH OF AREA...BUT
SOMETHING TO WATCH AS SHARP LINE FROM VFR TO IFR. OTHERWISE
LOOKING FINE AS CIRRUS WILL INCREASE OVER THE AREA AND SOUTH WINDS
HOLD UP IN THE 5 TO 15 KT RANGE INTO MONDAY MORNING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...GUST/DK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
301 PM CST SAT DEC 5 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM CST SAT DEC 5 2015
THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH VERY MILD TEMPS
CONTINUING INTO THE MIDDLE OF NEXT WEEK. MODELS ARE IN GOOD
AGREEMENT WITH LARGER SCALE FEATURES...BUT STRUGGLING WITH LOW
LEVEL TEMPS. THE MAV MOS GUIDANCE HAS THE BEST HANDLE ON TEMPS IN
THE NEAR TERM AT LEAST.
FOR TONIGHT...THERE HAS BEEN MELTING OF SNOW IN THE PAST 24
HOURS...AND DEWPOINTS ARE IN THE LOW/MID 30S OVER THE SNOW FIELD
THIS AFTERNOON. EVEN WITH WESTERLY WINDS IN THE 5 TO 10 MPH RANGE
FOR MUCH OF THE NIGHT...THERE SHOULD BE AT LEAST SOME PATCHY FOG
OVER THE SNOW AREAS. MODELS DO NOT INDICATE TOO MUCH
FOG...ALTHOUGH THE LATEST HRRR IS INDICATING SOME LOWER VSBYS OVER
MN SINCE WINDS HERE MAY BE FAIRLY LIGHT. TEMPS WILL BE WELL ABOVE
NORMAL GENERALLY IN THE LOW/MID 20S.
FOR SUNDAY...TEMPERATURES WILL BE VERY SIMILAR TO TODAY AND
PERHAPS A FEW DEGREES WARMER WITH 925MB TEMPS NEAR +10C BY
AFTERNOON. WE WILL CONTINUE TO GO THE WARMEST OVER THE SNOW FREE
AREAS IN NORTHEAST ND.
ON SUNDAY NIGHT...ANOTHER MILD NIGHT WITH SOUTHERLY WINDS AROUND
10 MPH THAT SHOULD PRECLUDE ANY FOG FORMATION.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 300 PM CST SAT DEC 5 2015
ON MONDAY...925MB TEMPS COOL SOME BUT ARE STILL WELL ABOVE 0C.
THERE SHOULD BE WESTERLY SFC WINDS THAT WILL ONCE AGAIN BOOST
TEMPS TO AROUND 40 PERHAPS EVEN MID 40S FOR SOME WITH MINIMAL SNOW
COVER.
FOR MONDAY NIGHT...EXPECT INCREASING CLOUDS AND WINDS REMAINING
A BIT ELEVATED. THIS SHOULD MEAN A VERY MILD NIGHT WITH OVERNIGHT
LOWS AROUND 30.
FOR TUE...A SHORTWAVE WILL SWING THROUGH THE REGION AND BRING A
LOW CHANCE FOR SOME LIGHT RAIN. THERE COULD BE A BRIEF WINDOW
EARLY TUE MORNING FOR SOME FREEZING RAIN...BUT WITH TEMPS SO MILD
NOT EXPECTING THIS TO BE ANY TYPE OF THREAT SO WILL KEEP IT ALL
LIQUID RAIN FOR NOW. TEMPS SHOULD ONCE AGAIN WARM TO AROUND 40 OR
THE MID 40S FOR ALL AREAS WITH MORE CLOUDS IN THE EAST.
FORECAST STARTING ON WEDNESDAY NIGHT LOOKS A BIT ON THE ACTIVE
SIDE...POTENTIALLY. THE 12Z GFS AND ECMWF BOTH HAVE AN UPPER LOW
BARRELING ALONG THE CANADIAN BORDER EASTWARD ON WEDNESDAY NIGHT. LOW
LEVEL TEMPS ARE ABOVE FREEZING AHEAD OF THIS SYSTEM...THEN DROPPING
BELOW FREEZING. WHICH MEANS RAIN CHANGING TO SNOW POSSIBLY. THE BEST
CHANCE FOR PRECIPITATION WITH THIS SYSTEM WILL BE OVER NORTHWESTERN
MN...WHERE THE ECMWF HAS SIGNIFICANT SNOWFALL FORECASTED. MODELS ARE
TRENDING A LITTLE FURTHER SOUTH AND WETTER WITH THE WED NIGHT/THU
SYSTEM. A SHOT OF COOLER AIR IS THEN COMING FOR THE WEEKEND. THE GFS
HAS A POTENT LOW MOVING NE ACROSS THE REGION FOR SATURDAY...WHILE
THE ECMWF KEEPS IT A BIT FURTHER EAST AND A LITTLE WEAKER. THE ECMWF
HAS TRENDED WESTWARD A BIT WITH THIS ONE...BACK FURTHER WEST INTO
THE RED RIVER VALLEY. SO...A CHANCE FOR PRECIP ON SATURDAY SEEMS
REASONABLE...WITH COOLER TEMPS COMPARED TO THE PREVIOUS WEEK`S
WARMTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1210 PM CST SAT DEC 5 2015
EXPECTING MAINLY HIGH CLOUDS TODAY. HOWEVER...AN AREA OF STRATUS HAS
EXPANDED SOUTH OF KBJI. HAVE OPTED TO INCLUDE A TEMPO GROUP FOR A
REASONABLE LIKELIHOOD OF MVFR CIGS AT KBJI THIS AFTERNOON. MODEL
SOUNDINGS ARE INDICATING PLENTY OF LOW LEVEL RELATIVE HUMIDITY THE
LOW LEVELS AT KBJI THIS AFTERNOON...AT LEAST. ALSO HAVE A CONCERN
FOR FOG TONIGHT ACROSS ENTIRE AREA. MODELS HAVE SATURATED LOW LEVELS
FOR MOST SITES...BUT VERY SHALLOW. LATEST MET/MAV GUIDANCE AND HRRR
MODEL DON`T INDICATE FOG BEING A CONCERN. HOWEVER...HARD TO SAY IF
THEY ARE PROPERLY CONSIDERING MELTING EFFECTS. BUFKIT INDICATES
MIXING COULD LIMIT DEVELOPMENT. FOG MIGHT BE MORE ON THE PATCHY SIDE
IF IT DEVELOPS...SO KEPT IT OUT OF TAFS FOR NOW. MAIN CONCERN WILL
BE POTENTIAL FOR STRATUS IN KBJI AREA...AND HOW LONG IT MIGHT
LINGER.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...DK
LONG TERM...DK/KNUTSVIG
AVIATION...RK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1220 AM CST SAT DEC 5 2015
.UPDATE...
ISSUED AT 1218 AM CST SAT DEC 5 2015
NO CHANGES REQUIRED TO THE FORECAST.
UPDATE ISSUED AT 929 PM CST FRI DEC 4 2015
NO SIGNIFICANT UPDATES TO THE GOING FORECAST THIS EVENING. STRONG
SOUTHERLY WINDS AHEAD OF A COLD FRONT IN EASTERN NORTH DAKOTA
WITH LIGHT TO MODERATE SOUTHWEST TO WEST WINDS OVER WESTERN NORTH
DAKOTA WILL KEEP TEMPERATURES RATHER UNIFORM ACROSS THE FORECAST
AREA TONIGHT...EVEN OVER THE REMAINING SNOWPACK OVER THE FAR SOUTH
CENTRAL INTO THE JAMES RIVER VALLEY. INCREASING CLOUDS TRACKING
NORTHEAST FROM SOUTH DAKOTA WILL ALSO HELP KEEP TEMPERATURES FROM
FALLING LIKE THE PAST FEW NIGHTS OVER THE SNOWPACK. UPDATED LATEST
SENSIBLE WEATHER ELEMENTS AND INTERPOLATED TO A CONSENSUS OF SHORT
TERM HOURLY TEMPERATURES FOR THE OVERNIGHT PERIOD. RESULTING IN
VERY FEW CHANGES FROM THE PREVIOUS FORECAST.
UPDATE ISSUED AT 627 PM CST FRI DEC 4 2015
A WEAK COLD FRONT WILL TRAVERSE THE FORECAST AREA TONIGHT. STRONG
SOUTHERLY FLOW OVER THE JAMES RIVER VALLEY EARLY THIS EVENING WILL
DIMINISH BY LATE EVENING AS FLOW SHIFTS MORE SOUTHWEST...AND
EVENTUALLY WEST SATURDAY MORNING.
THE SOUTHWEST TO WEST FLOW SHOULD KEEP TEMPERATURES RATHER UNIFORM
TONIGHT COMPARED TO PREVIOUS NIGHTS...EVEN OVER THE DECAYING
SNOWPACK. THE TURBULENCE IN THE LOW LEVELS SHOULD ALSO HELP TO
INHIBIT ANY FOG FORMATION WHERE SNOWMELT OCCURRED DURING THE DAY.
FOR THE EVENING UPDATE...ONLY SOME MINOR ADJUSTMENTS TO SKY COVER
AND POPULATED THE LATEST SENSIBLE WEATHER ELEMENTS.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
MILD AND QUIET WEATHER WILL CONTINUE THROUGH SATURDAY.
AS OF 21 UTC...IT IS APPARENT THAT THE LOW-LEVEL INVERSION IS ONLY
SLOWLY BEING ERODED IN SOUTHERLY FLOW...AS SURFACE GUSTS ARE BEING
HELD UNDER 30 KT EVEN IN THE JAMES RIVER VALLEY. FORECAST SOUNDING
PROFILES FROM THE RAP AND HRRR CONTINUE TO SUPPORT WINDS AROUND
60 KT WITHIN 2000 FT AGL THROUGH EARLY EVENING IN EAST CENTRAL ND
AND SO WE WILL HAVE TO MONITOR FOR STRONGER GUSTS...BUT THE CHANCE
OF ADVISORY-TYPE GUSTS APPEARS TO BE DWINDLING.
A MODEST COLD FRONT WILL CROSS THE AREA TONIGHT...TURNING WINDS TO
THE WEST...AND COOLING THE AIR MASS A BIT BY SATURDAY WHEN 850-MB
TEMPERATURES ARE EXPECTED TO DROP TO +1 TO +3 C. HOWEVER...GIVEN
THE FAVORABLE LOW-LEVEL WESTERLY FLOW AND CONTINUED EROSION OF THE
SNOW PACK...WE STILL EXPECT HIGHS IN THE 40S F IN MANY PLACES ON
SATURDAY. IT ALSO APPEARS THAT THE NEAR-SURFACE LAYER WILL BE TOO
TURBULENT TO SUPPORT FOG FORMATION TONIGHT IN AREAS THAT HAVE HAD
SNOWMELT DURING THE DAY.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CST FRI DEC 4 2015
THE MAIN HIGHLIGHTS IN THE LONG TERM PERIOD ARE ABOVE NORMAL HIGH
TEMPERATURES THROUGH THE PERIOD...WITH HIGHS IN THE 40S AND SOME 50S
ESPECIALLY SUNDAY AND WEDNESDAY. A COOLING TREND INITIATES FRIDAY
AND CONTINUES THROUGH THE UPCOMING WEEKEND. ALTHOUGH COOLER
CONDITIONS EXPECTED FRIDAY...HIGH TEMPERATURES STILL REMAIN ABOVE
NORMAL WITH HIGHS 35F TO 40F. THE OVERALL PATTERN OF A NEAR ZONAL
FLOW CONTINUES WITH QUICK MOVING SHORTWAVES AND ASSOCIATED SURFACE
FEATURES SLIDING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE MAIN
DIFFERENCE ON THE 12Z GFS/ECMWF MODELS RUNS TODAY IS A MORE
WIDESPREAD CHANCE OF MOSTLY RAIN SHOWERS ON TUESDAY ACROSS WESTERN
AND CENTRAL NORTH DAKOTA. ALTHOUGH SOME SNOW SHOWERS ARE POSSIBLE
DURING THE EARLY MORNING. ANOTHER FAIRLY WEAK SHORTWAVE IS SLATED
FOR THURSDAY INTO THURSDAY NIGHT....WITH A POTENTIALLY STRONGER
SHORTWAVE FRIDAY INTO THE WEEKEND. HOWEVER IT IS EVIDENT JUST FROM
THE GFS ENSEMBLE HEIGHTS THAT NEXT WEEKENDS SHORTWAVE HAS A LOT OF
UNCERTAINTY...WITH SEVERAL POSSIBLE SOLUTIONS. THE SUPERBLEND
CURRENTLY HAS A SLIGHT CHANCE/CHANCE OF RAIN AND SNOW FRIDAY/FRIDAY
NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1218 AM CST SAT DEC 5 2015
VFR CONDITIONS AT ALL TAF SITES THROUGH THE TAF PERIOD WITH WEST
WINDS DEVELOPING AT ALL SITES BY THE EARLY MORNING HOURS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AJ
SHORT TERM...CJS
LONG TERM...KS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
941 PM EST SUN DEC 6 2015
.SYNOPSIS...
WEAK LOW PRESSURE WILL MOVE THROUGH THE REGION TONIGHT INTO
MONDAY. HIGH PRESSURE WILL BUILD BACK IN FOR TUESDAY. ANOTHER LOW
PRESSURE SYSTEM WILL AFFECT THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH MONDAY/...
CLOUDS ARE BECOMING THE KEY ELEMENT TO THE FORECAST
TONIGHT...FORCING A FEW CHANGES THIS EVENING. CURRENT SATELLITE
IMAGERY SHOWS CIRRUS DEPARTING OHIO AND KENTUCKY TO THE
EAST...WITH A BROKEN DECK OF MID CLOUDS (8KFT-12KFT) EXTENDING
ACROSS SOUTHERN MICHIGAN...NORTHEASTERN INDIANA...AND WESTERN
OHIO. BEHIND THIS...A SOLID DECK OF STRATOCUMULUS (3KFT-6KFT) IS
PERHAPS THE MOST EASILY DISTINGUISHED OF THE FEATURES ON THE
11U-3.9U SATELLITE PRODUCT. THIS CLOUD DECK HAS JUST ENTERED THE
FORECAST AREA...IN ADVANCE OF THE WEAK SURFACE AND MID-LEVEL LOW
PRESSURE CENTERS...AND WILL CONTINUE TO SPREAD INTO OHIO AND
KENTUCKY OVER THE NEXT SEVERAL HOURS.
AHEAD OF THESE CLOUDS...TEMPERATURES HAVE TAKEN A REMARKABLY QUICK
TURN FOR THE BASEMENT IN CENTRAL OHIO...WITH VALUES ALREADY
SEVERAL DEGREES BELOW FREEZING EAST OF COLUMBUS. UNTIL THE CLOUDS
GET INTO THE REGION...THESE TEMPERATURES SHOULD CONTINUE TO DROP.
HOWEVER...CONDITIONS UNDER THE STRATOCUMULUS DECK HAVE BEEN QUITE
A BIT WARMER...WITH TEMPERATURES NEAR 40 IN CENTRAL INDIANA...AND
IN THE MID 40S IN WEST-CENTRAL INDIANA. A COMPLETELY NEW SET OF
TEMPERATURE GRIDS HAS BEEN CREATED...INDICATING STEADY
TEMPERATURES IN THE WESTERN HALF OF THE CWA...AND SOME ADDITIONAL
COOLING IN THE EAST BEFORE RISING AGAIN AFTER 06Z. SKY GRIDS WERE
ALSO ADJUSTED TO INCREASE VALUES ONCE THE STRATOCUMULUS DECK
ARRIVES.
PRECIPITATION AMOUNTS TO THE WEST HAVE BEEN VERY LIGHT...WITH
GENERALLY TRACE TO 0.02" REPORTS ON THE HOURLY OBSERVATIONS. THE
AREA OF SHOWERS MAY EXPAND VERY SLIGHTLY IN COVERAGE AND
INTENSITY OVER THE NEXT FEW HOURS...BUT THE CHANCES OF MEASURABLE
PRECIPITATION FOR THE ILN FORECAST AREA STILL SEEM WELL COVERED BY
THE CURRENT ARRANGEMENT OF POPS. BASED ON RADAR TRENDS...THE POPS
WERE ADJUSTED NORTHWARD BY ONE OR TWO TIERS OF COUNTIES. A TIMING
COMPROMISE BETWEEN THE HRRR (SLIGHTLY FAST) AND NAM/GFS (SLIGHTLY
SLOW) MATCHED WELL WITH THE PREVIOUS FORECAST...AND WAS RETAINED.
A WARM LAYER AT AROUND 950MB WILL ENSURE THAT PRECIPITATION THAT
FALLS REMAINS LIQUID...THOUGH SURFACE TEMPERATURES AT ONSET MAY BE
IN THE MID 30S.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
UPPER LOW MOVES ACROSS THE CWA MONDAY MORNING. CONTINUED LOW POPS
ACROSS THE SOUTHEAST PORTION OF THE CWA UNTIL THE LOW EXITS.
BEHIND IT...ENOUGH DRYING IN THE MID LEVELS ALONG WITH SUBSIDENCE
FROM WEAK HIGH PRESSURE WILL ALLOW FOR SOME SUNSHINE TO RETURN
FOR THE AFTERNOON AND THAT WILL KEEP MAXIMA ABOVE AVERAGE FOR THIS
TIME OF THE YEAR.
HIGH PRESSURE MOVES TO THE EAST MONDAY NIGHT...AND SOUTHERLY FLOW
AROUND THE HIGH WILL LIKELY BRING AN INCREASE IN CLOUDS MONDAY
NIGHT BUT IT SHOULD REMAIN DRY.
GENERALLY ZONAL FLOW ALOFT WILL BE IN PLACE TUESDAY/TUESDAY
NIGHT WITH DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AN UPPER LEVEL S/WV WILL TRAVERSE OUR REGION ON WEDNESDAY. THIS
FEATURE...ALONG WITH A SFC TROF AXIS...WILL BRING A CHANCE OF
SHOWERS. SYSTEM MOVES EAST WEDNESDAY NIGHT...FOLLOWED TO A RETURN OF
DRY WEATHER ON THURSDAY.
THE FORECAST IS STILL A LITTLE BIT UNCLEAR AS WE HEAD INTO THE END
OF THE WEEK...ESPECIALLY IN REGARDS TO AREAL COVERAGE AND
PROBABILITY OF PCPN. THE FLOW DOES BECOME MORE AMPLIFIED WITH A
LARGE SCALE MID LEVEL TROUGH DIGGING OUT FROM THE WESTERN U.S. AND
RIDGING DEVELOPING OVER THE EASTERN U.S. S/WV ENERGY FOR
THURSDAY/FRIDAY STILL VARYS AMONGST THE MODELS IN TERMS OF HOW
STRONG/DEEP IT WILL BE AS IT PASSES THROUGH THE GREAT LAKES. HAVE
KEPT POPS ON THE LOW SIDE DUE TO HIGH UNCERTAINTY. FOR
SATURDAY...LOOKS LIKE MID LEVEL RIDGING AND A WARM FRONT WILL LIFT
THROUGH OUR REGION. WARMER TEMPERATURES AND SOME WAA SHOWERS WILL BE
POSSIBLE. LOW PRESSURE AND A SLOW MOVING COLD FRONT WILL ENCROACH
THE REGION ON SUNDAY WITH A HIGHER THREAT FOR SHOWERS EXPECTED.
IT WILL CONTINUE TO BE WARMER THAN NORMAL THROUGH THE PERIOD WITH
TEMPERATURES WARMING INTO THE 60S BY THE WEEKEND...WHICH IS SOME 20
DEGREES ABOVE NORMAL FOR MID DECEMBER. THESE VALUES MAY CHALLENGE
RECORD HIGHS.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL CONTINUE FOR THE NEXT SEVERAL HOURS...WITH
GENERALLY CLEAR SKIES OVER THE REGION. THERE IS SOME POTENTIAL FOR
LIGHT MVFR FOG TO DEVELOP OVER THE AREA...PRIMARILY DURING THE
FIRST HALF OF THE OVERNIGHT PERIOD.
ATTENTION WILL THEN FOCUS ON THE AREA OF SCATTERED SHOWERS AND
ASSOCIATED CLOUDS LOCATED TO THE WEST OF THE REGION THIS EVENING.
CHANCES FOR PRECIPITATION WILL BE GREATEST AT THE CINCINNATI TAF
SITES...WHERE SOME MVFR CONDITIONS MAY OCCUR IN RAIN SHOWERS.
THOUGH CEILINGS SHOULD GENERALLY REMAIN IN THE VFR TO HIGHER-END
MVFR CATEGORIES...THERE IS SOME POTENTIAL FOR CEILINGS BELOW 2000
FEET EARLY MONDAY MORNING THROUGH EARLY MONDAY AFTERNOON.
SKIES ARE EXPECTED TO GRADUALLY CLEAR OUT MONDAY
AFTERNOON...THOUGH SOME BRIEF MVFR CEILINGS MAY PERSIST FOR A
WHILE. VFR CONDITIONS ARE EXPECTED BY EVENING...WITH LIGHT WINDS
SWITCHING FROM NORTHWEST TO SOUTHWEST.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BPP
NEAR TERM...HATZOS
SHORT TERM...BPP
LONG TERM...HICKMAN
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
651 PM EST SUN DEC 6 2015
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL LINGER OVER THE UPPER OHIO VALLEY
THROUGH TONIGHT. LOW PRESSURE WILL PASS ACROSS SOUTHERN OHIO
MONDAY. A WARM FRONT WILL LIFT NORTH ACROSS THE REGION LATE
TUESDAY AND TUESDAY NIGHT. A COLD FRONT WILL FOLLOW ON WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THICKER CIRRUS WILL MOVE EAST OF THE REGION THIS EVENING. WILL
THEN HAVE A PERIOD OF CLEAR OR MOSTLY CLEAR SKIES BEFORE THE NEXT
AREA OF LOW PRESSURE BRINGS CLOUDS IN FROM THE WEST. THERE MAY BE
SOME VIRGA TOWARD SUNRISE BUT BELIEVE IT WILL BE ACROSS THE SOUTH.
AT THIS POINT WE DO NOT THINK THE SPRINKLES WILL REACH THE
SURFACE.
THERE CONTINUES TO BE SOME LOW LEVEL MOISTURE ACROSS THE AREA.
WILL HAVE TO MONITOR FOR THE DEVELOPMENT OF FOG OVERNIGHT.
BELIEVE THE BEST CHANCES OF FOG IN THE MORNING WILL BE THE
LOCATIONS THAT CAN HANG ONTO THE MID 30 DEWPOINTS. SO WITH THAT
SAID WE HAVE PLACED A MENTION OF FOG ACROSS THE SOUTHERN AND
WESTERN PORTION OF THE COUNTY WARNING AREA. HRRR IS SHOWING THE
AREA OF FOG/STRATUS OVER SE MI EXPANDING INTO LUCAS AND POSSIBLY
WOOD/OTTAWA. WE MAY GET DENSE FOG DEVELOP THERE BUT AT THE SAME
TIME THE ADVANCING CLOUDS FROM THE WEST MAY INHIBIT THAT.
LOWS WILL ONCE AGAIN DIP BELOW FREEZING AT MOST LOCATIONS.
ONLY CHANGE WITH THE EARLY EVENING UPDATE WAS TO INCREASE SKY
COVERAGE FOR NW OH OVERNIGHT AND INTO MONDAY...RETAINING THE LOW
STRATUS LONGER.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
UPPER LEVEL LOW PRESSURE WILL MOVE ACROSS OHIO ON MONDAY BUT THE
MAIN AREA OF SHOWERS/SPRINKLES WILL BE SOUTH OF THE COUNTY WARNING
AREA. RIDGING AT THE SURFACE AND ALOFT WILL BRIEFLY BE LOCATED
OVER THE AREA MONDAY NIGHT. THIS HIGH WILL SHIFT EASTWARD ON
TUESDAY AS THE NEXT STORM SYSTEM MOVES INTO THE WESTERN GREAT
LAKES. SOUTHWESTERLY WINDS WILL INCREASE TUESDAY AFTERNOON INTO
TUESDAY NIGHT AS A WARM FRONT LIFTS NORTHWARD ACROSS THE REGION.
THE UPPER LEVEL TROUGH WILL PASS OVERHEAD ON WEDNESDAY. NOT ALL
THAT MUCH MOISTURE TO WORK WITH SO ONLY WENT WITH CHANCE POPS.
TEMPERATURES WILL NOT VERY MUCH THROUGH THE SHORT TERM WITH HIGHS
EACH AFTERNOON REMAINING ABOVE SEASONAL AVERAGES.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE LAST OF A SERIES OF DECENT SHORT WAVES/UPPER LOWS WILL CROSS THE
GREAT LAKES THURSDAY INTO FRIDAY. THERE ARE SOME TIMING AND LOCATION
DIFFERENCES IN THE MODELS. WILL CONTINUE WITH A SLIGHT CHANCE OF
SHOWERS THURSDAY FOR EXTREME NORTHEAST OH AND NORTH WEST PA. WILL
HAVE A SOMEWHAT BETTER CHANCE THURSDAY NIGHT INTO FRIDAY BUT NOT
EXPECTING ANYTHING OF CONSEQUENCE.
THE RIDGE IS PROGGED TO BUILD GOING INTO THE WEEKEND...THEN IT IS A
MATTER OF TIMING WITH THE NEXT FRONT. THE MODELS HAVE TRENDED
SLIGHTLY SLOWER AS VIRTUALLY ALL OF THE MODELS DEVELOP A WAVE ON THE
FRONT. THERE WOULD APPEAR A BETTER CHANCE OF SHOWERS IN TOLEDO
VERSUS YOUNGSTOWN OVER THE WEEKEND AS THE FRONT NEARS NORTHWEST OHIO
AND WILL INDICATE SUCH IN THE FORECAST BUT THERE IS LOW CONFIDENCE
AT THIS TIME.
IN ANY CASE...IT WILL CONTINUE UNSEASONABLY WARM. HIGHS THURSDAY AND
FRIDAY MOSTLY IN THE 50S...THEN UP TO AROUND 60 ON THE WEEKEND...
PERHAPS WARMER IF THE RAIN AND CLOUDS HOLD OFF.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS ACROSS NRN OHIO AND NWRN PA THIS EVENING. TO THE
WEST UPPER LOW PRESSURE IS MOVING EAST OUT OF THE MIDWESTERN
STATES AND SHOULD TRACK ACROSS OHIO LATE TONIGHT AND EARLY MONDAY.
BEST MOISTURE WITH THE SYSTEM SHOULD REMAIN SOUTH OF THE AREA SO
AT THIS TIME ONLY BRINGING IN MID LEVEL CLOUDS TO THE REGION.
EXPECT AREAS OF FOG TO DEVELOP AGAIN THIS EVENING AND OVERNIGHT
ALTHOUGH WITH ADVANCING CLOUDS FROM THE WEST DO NOT EXPECT DENSE
FOG LIKE THE PAST TWO NIGHTS. STILL DID PUT IN POSSIBLE IFR VSBYS
AT TOL FDY CAK AND YNG WITH POSSIBLE MVFR AT CLE AND MFD. VFR
EXPECTED ON MONDAY AFTER ANY FOG THAT DEVELOPS BURNS OFF.
OUTLOOK...NON-VFR MIST/FOG POSSIBLE LATE MONDAY NIGHT AND TUESDAY
MORNING.
&&
.MARINE...
A LIGHT SOUTH TO SOUTHWEST FLOW WILL CONTINUE ON LAKE ERIE TONIGHT
BUT LIGHT WINDS WILL SHIFT FROM A NORTHERLY DIRECTION ON MONDAY AS
WEAK LOW PRESSURE SLIDES ACROSS THE OHIO VALLEY.
THE FLOW SHOULD RETURN TO SOUTH TO SOUTHWEST MONDAY NIGHT AS HIGH
PRESSURE BUILDS ACROSS THE MIDWEST. A SERIES OF FAST MOVING BUT
RELATIVELY WEAK WEATHER SYSTEMS WILL CROSS THE GREAT LAKES THIS
WEEK...EACH WITH SOMEWHAT STRONGER SOUTHWEST WINDS AROUND 15 TO 20
KNOTS. THE AIR MASS WILL REMAIN WARM THOUGH AND MAXIMUM MIXING OF
THE WIND TO THE SURFACE IS UNLIKELY. SMALL CRAFT ADVISORIES MAY BE
NEEDED BUT NO GALES ARE EXPECTED.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MULLEN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...MULLEN/OUDEMAN
LONG TERM...KOSARIK
AVIATION...TK
MARINE...KOSARIK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
539 PM EST SAT DEC 5 2015
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH
SUNDAY...WITH DRY CONDITIONS EXPECTED. A WEAK AREA OF LOW PRESSURE
WILL MOVE THROUGH THE AREA SUNDAY NIGHT INTO MONDAY...PROVIDING A
CHANCE OF RAIN SHOWERS. GRADUALLY WARMING CONDITIONS ARE EXPECTED
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
ALTHOUGH MOST OF THE FORECAST AREA CLEARED OUT OF THE STRATUS/FOG
BY MID-AFTERNOON...A FEW PATCHES REMAINED IN PLACE. ONE PATCH HAS
BEEN CENTERED OVER FAYETTE AND GREENE COUNTIES. ANOTHER IS LOCATED
OVER THE NWS CLE FORECAST AREA...BUT HAS BEGUN MOVING INTO HARDIN
AND UNION COUNTIES. AS THE SUN BEGAN TO SET...VISIBILITIES IN
THESE AREAS QUICKLY DROPPED TO NEAR-ZERO...AND THERE IS EVERY
REASON TO BELIEVE THAT BOTH AREAS WILL CONTINUE TO EXPAND.
THUS...A DENSE FOG ADVISORY HAS BEEN ISSUED...COVERING 15 COUNTIES
(AND LIKELY TO EXPAND LATER THIS EVENING).
THE REST OF THE FORECAST IS UNCHANGED.
PREVIOUS DISCUSSION >
A SIGNIFICANT DENSE FOG EVENT...WITH SOME RIME ICING...OCCURRED
ACROSS THE AREA THIS MORNING. AS INDICATED IN A SOCIAL MEDIA POST
FROM OUR OFFICE EARLIER TODAY...THE LOW- LEVEL INVERSION WAS
EXCEPTIONALLY STRONG...WARMING FROM ABOUT 25F AT THE SURFACE TO
50F AT 2KFT. THIS INVERSION IS MUCH TOO STRONG TO BE TRULY
BROKEN...BUT THERE HAS BEEN JUST ENOUGH MODIFICATION TO THE AIR
MASS TO ALLOW FOR THE STRATUS TO STEADILY DISSIPATE OVER THE PAST
FEW HOURS.
OVERALL...BOUNDARY LAYER MOISTURE HAS CHANGED VERY LITTLE...AND
SURFACE DEWPOINTS HAVE ACTUALLY INCREASED TODAY. THIS CONTRASTS
REMARKABLY WITH RAW GFS / GFS MOS PROJECTIONS...WHICH INITIALIZED
AT 12Z WITH SURFACE DEWPOINT ERRORS OF AS MUCH AS 20
DEGREES...ERRORS WHICH RENDER THE MODEL MOSTLY USELESS FOR THIS
FORECAST CYCLE. OTHER MODELS WERE ALSO A LITTLE TOO LOW ON
DEWPOINTS...BUT RAW NAM NUMBERS (FOR BOTH T/TD) WERE ALIGNING VERY
CLOSE TO CURRENT OBSERVATIONS.
USING THESE NUMBERS AS GUIDANCE...AS WELL AS CONTINUED PATTERN
RECOGNITION...THERE IS GOOD REASON TO FORECAST ANOTHER NIGHT OF
FOG FOR THE ILN FORECAST AREA. WORKING AGAINST THE THREAT WILL BE
THAT THE CENTER OF THE HIGH WILL NOT BE DIRECTLY OVER THE REGION
(ALLOWING SOME LIGHT WIND FLOW)...AND THE VERY-SLIGHTLY-MODIFIED
AIR MASS MEANS THAT FOG MAY BE A LITTLE MORE SHALLOW THAN LAST
NIGHT. NONETHELESS...THE STABLE AIR MASS AND STRONG INVERSION WILL
CONTINUE TO SUPPORT A NEAR-SURFACE STABLE LAYER...AND STRATUS/FOG
DEVELOPMENT IS EXPECTED TO BEGIN QUICKLY AFTER SUNSET. FOG HAS
BEEN INCLUDED WITH EMPHASIS IN THE GRIDDED FORECAST AND THE
HAZARDOUS WEATHER OUTLOOK. THE ONLY REAL UNCERTAINTY IS IN THE FAR
SOUTHERN SECTIONS OF THE CWA...WHERE CONDITIONS CLEARED OUT MORE
QUICKLY THIS MORNING...AND HRRR VISIBILITY PROJECTIONS SUGGEST THE
DENSE FOG MAY STOP SHORT OF REACHING.
WITH LITTLE CHANGE TO THE AIR MASS...MIN TEMPS WERE KEPT VERY
CLOSE TO VALUES FROM LAST NIGHT. HOWEVER...WITH THE TIMING AND
PLACEMENT OF THE EVENTUAL PATCHES OF FOG/STRATUS TO DEVELOP
(EVENTUALLY BECOMING AT LEAST SOMEWHAT WIDESPREAD)...THE EXACT
MIN TEMPERATURE FORECAST FOR ANY GIVEN LOCATION HAS A SLIGHTLY
LOWER CONFIDENCE THAN USUAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
FOG WILL LIKELY BE IN PLACE FOR MOST OF THE AREA TO START SUNDAY
MORNING. WITH A SWITCH TO SOUTHERLY NEAR-SURFACE FLOW...AND A
VERY SLIGHTLY WARMER/DRIER AIR MASS OVERALL COMPARED TO THIS
MORNING...THE EXPECTATION IS THAT FOG/STRATUS WILL DISSIPATE A
LITTLE QUICKER THAN OCCURRED TODAY. THE MAX TEMPERATURE FORECAST
WAS STILL KEPT SOMEWHAT CONSERVATIVE DUE TO THE POTENTIAL FOR
CLOUDS...BUT THE ENTIRE CWA WILL LIKELY MAKE IT INTO THE MIDDLE TO
UPPER 40S ONCE THINGS CLEAR OUT...WITH LOWER 50S IN THE FAR
SOUTHEAST (WHERE SUNNY CONDITIONS ARE EXPECTED EVEN SOONER).
ON SUNDAY NIGHT...A WELL-DEFINED UPPER LOW WILL MOVE EAST THROUGH
THE SOUTHERN GREAT LAKES / NORTHERN OHIO VALLEY. THIS LOW IS NOT
PARTICULARLY STRONG...AND ASIDE FROM AN UNIMPRESSIVE SURFACE WIND
SHIFT...LOW-LEVEL FORCING IS EXPECTED TO BE VERY WEAK AS WELL.
THE COOLING AIR ALOFT WILL FINALLY HELP TO ERODE SOME OF THE
STRONG INVERSION...BUT MOISTURE WILL REMAIN FAIRLY SHALLOW...AND
WIDESPREAD PRECIPITATION IS NOT EXPECTED TO DEVELOP. THE CURRENT
RANGE OF POP VALUES (10-40 PERCENT FROM NORTH TO SOUTH) STILL
MATCHES FORECAST EXPECTATIONS NICELY...WITH TIMING REFINED BASED
ON 12Z RUNS...AND THE AREA SLIGHTLY EXPANDED. BECAUSE OF THE
INVERSION...THIS PRECIPITATION WILL LIKELY BE ALL RAIN...EVEN
THOUGH SURFACE TEMPERATURES EARLY MONDAY MORNING WILL BE IN THE
MID 30S.
SOME WEAK COLD ADVECTION BEHIND THE UPPER LOW WILL KEEP
TEMPERATURES IN THE MID 40S ON MONDAY...NEAR OR JUST ABOVE
NORMAL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A COUPLE OF PROGRESSIVE S/WVS ARE FORECAST TO TRAVERSE FROM WEST TO
EAST ACROSS THE GREAT LAKES AND OHIO VALLEY REGION DURING THE EARLY
TO MID WEEK PERIOD. TUESDAY/S DISTURBANCE IS EXPECTED TO BE WEAK AND
MOISTURE STARVED...SO ONLY CLOUDS ARE FORECAST. THE SECOND
DISTURBANCE FOR WEDNESDAY/WEDNESDAY NIGHT IS A LITTLE STRONGER AND
HAS DEEPER MOISTURE IN ASSOCIATION WITH A COLD FRONT. HAVE CONTINUE
WITH A CHANCE OF SHOWERS DURING THIS TIME FRAME.
THE FORECAST BECOMES LESS CLEAR AS WE HEAD INTO THE END OF THE
WEEK...ESPECIALLY IN REGARDS TO AREAL COVERAGE AND PROBABILITY OF
PCPN. THE FLOW DOES BECOME MORE AMPLIFIED WITH A LARGE SCALE MID
LEVEL TROUGH DIGGING OUT ACROSS THE WESTERN U.S. AND RIDGING
DEVELOPING OVER THE EASTERN U.S. S/WV ENERGY FOR THURSDAY/FRIDAY
VARIOUS AMONGST THE MODELS IN TERMS OF HOW STRONG/DEEP IT WILL BE AS
IT PASSES THROUGH THE GREAT LAKES. HAVE KEPT POPS ON THE LOW SIDE
DUE TO HIGH UNCERTAINTY. FOR SATURDAY...LOOKS LIKE MID LEVEL RIDGING
AND A WARM FRONT WILL LIFT THROUGH OUR REGION. WARMER TEMPERATURES
AND SOME WAA SHOWERS WILL BE POSSIBLE.
IT WILL CONTINUE TO BE WARMER THAN NORMAL THROUGH THE PERIOD WITH
TEMPERATURES WARMING INTO THE UPPER 50S TO THE LOWER 60S BY THE
WEEKEND...WHICH IS SOME 20 DEGREES ABOVE NORMAL FOR MID DECEMBER.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
LIFR CONDITIONS IN FOG AND FREEZING FOG WILL RAPIDLY BECOME VFR
THIS AFTERNOON WITH NO CIG AND PATCHY MVFR VSBYS THROUGH ABOUT
20Z. EXPECT THE FOG TO MAKE ANOTHER APPEARANCE TONIGHT AS THE
TEMPERATURE INVERSION PERMITS MOISTURE TO BE TRAPPED IN AN EVEN
SHALLOWER LAYER TONIGHT. WHILE LAYER MAY BE MUCH MORE
SHALLOW...THIS WILL JUST MEAN THAT THE FOG THAT DEVELOPS TONIGHT
WILL BE QUICKER TO DISSIPATE TOMORROW. IT SHOULD BE JUST AS DENSE
GIVEN THAT THE WIND FIELDS WILL NOT BE SUBSTANTIAL TO SCOUR OUT
ANY LOW LEVEL MOISTURE.
OUTLOOK...MVFR CEILINGS POSSIBLE SUNDAY NIGHT INTO MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...DENSE FOG ADVISORY UNTIL 10 AM EST SUNDAY FOR OHZ026-044-045-
051>054-061>064-071>073-080.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS/NOVAK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
348 PM EST SAT DEC 5 2015
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH
SUNDAY...WITH DRY CONDITIONS EXPECTED. A WEAK AREA OF LOW PRESSURE
WILL MOVE THROUGH THE AREA SUNDAY NIGHT INTO MONDAY...PROVIDING A
CHANCE OF RAIN SHOWERS. GRADUALLY WARMING CONDITIONS ARE EXPECTED
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A SIGNIFICANT DENSE FOG EVENT...WITH SOME RIME ICING...OCCURRED
ACROSS THE AREA THIS MORNING. AS INDICATED IN A SOCIAL MEDIA POST
FROM OUR OFFICE EARLIER TODAY...THE LOW-LEVEL INVERSION WAS
EXCEPTIONALLY STRONG...WARMING FROM ABOUT 25F AT THE SURFACE TO
50F AT 2KFT. THIS INVERSION IS MUCH TOO STRONG TO BE TRULY
BROKEN...BUT THERE HAS BEEN JUST ENOUGH MODIFICATION TO THE AIR
MASS TO ALLOW FOR THE STRATUS TO STEADILY DISSIPATE OVER THE PAST
FEW HOURS.
OVERALL...BOUNDARY LAYER MOISTURE HAS CHANGED VERY LITTLE...AND
SURFACE DEWPOINTS HAVE ACTUALLY INCREASED TODAY. THIS CONTRASTS
REMARKABLY WITH RAW GFS / GFS MOS PROJECTIONS...WHICH INITIALIZED
AT 12Z WITH SURFACE DEWPOINT ERRORS OF AS MUCH AS 20
DEGREES...ERRORS WHICH RENDER THE MODEL MOSTLY USELESS FOR THIS
FORECAST CYCLE. OTHER MODELS WERE ALSO A LITTLE TOO LOW ON
DEWPOINTS...BUT RAW NAM NUMBERS (FOR BOTH T/TD) WERE ALIGNING VERY
CLOSE TO CURRENT OBSERVATIONS.
USING THESE NUMBERS AS GUIDANCE...AS WELL AS CONTINUED PATTERN
RECOGNITION...THERE IS GOOD REASON TO FORECAST ANOTHER NIGHT OF
FOG FOR THE ILN FORECAST AREA. WORKING AGAINST THE THREAT WILL BE
THAT THE CENTER OF THE HIGH WILL NOT BE DIRECTLY OVER THE REGION
(ALLOWING SOME LIGHT WIND FLOW)...AND THE VERY-SLIGHTLY-MODIFIED
AIR MASS MEANS THAT FOG MAY BE A LITTLE MORE SHALLOW THAN LAST
NIGHT. NONETHELESS...THE STABLE AIR MASS AND STRONG INVERSION WILL
CONTINUE TO SUPPORT A NEAR-SURFACE STABLE LAYER...AND STRATUS/FOG
DEVELOPMENT IS EXPECTED TO BEGIN QUICKLY AFTER SUNSET. FOG HAS
BEEN INCLUDED WITH EMPHASIS IN THE GRIDDED FORECAST AND THE
HAZARDOUS WEATHER OUTLOOK. THE ONLY REAL UNCERTAINTY IS IN THE FAR
SOUTHERN SECTIONS OF THE CWA...WHERE CONDITIONS CLEARED OUT MORE
QUICKLY THIS MORNING...AND HRRR VISIBILITY PROJECTIONS SUGGEST THE
DENSE FOG MAY STOP SHORT OF REACHING.
WITH LITTLE CHANGE TO THE AIR MASS...MIN TEMPS WERE KEPT VERY
CLOSE TO VALUES FROM LAST NIGHT. HOWEVER...WITH THE TIMING AND
PLACEMENT OF THE EVENTUAL PATCHES OF FOG/STRATUS TO DEVELOP
(EVENTUALLY BECOMING AT LEAST SOMEWHAT WIDESPREAD)...THE EXACT
MIN TEMPERATURE FORECAST FOR ANY GIVEN LOCATION HAS A SLIGHTLY
LOWER CONFIDENCE THAN USUAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
FOG WILL LIKELY BE IN PLACE FOR MOST OF THE AREA TO START SUNDAY
MORNING. WITH A SWITCH TO SOUTHERLY NEAR-SURFACE FLOW...AND A
VERY SLIGHTLY WARMER/DRIER AIR MASS OVERALL COMPARED TO THIS
MORNING...THE EXPECTATION IS THAT FOG/STRATUS WILL DISSIPATE A
LITTLE QUICKER THAN OCCURRED TODAY. THE MAX TEMPERATURE FORECAST
WAS STILL KEPT SOMEWHAT CONSERVATIVE DUE TO THE POTENTIAL FOR
CLOUDS...BUT THE ENTIRE CWA WILL LIKELY MAKE IT INTO THE MIDDLE TO
UPPER 40S ONCE THINGS CLEAR OUT...WITH LOWER 50S IN THE FAR
SOUTHEAST (WHERE SUNNY CONDITIONS ARE EXPECTED EVEN SOONER).
ON SUNDAY NIGHT...A WELL-DEFINED UPPER LOW WILL MOVE EAST THROUGH
THE SOUTHERN GREAT LAKES / NORTHERN OHIO VALLEY. THIS LOW IS NOT
PARTICULARLY STRONG...AND ASIDE FROM AN UNIMPRESSIVE SURFACE WIND
SHIFT...LOW-LEVEL FORCING IS EXPECTED TO BE VERY WEAK AS WELL.
THE COOLING AIR ALOFT WILL FINALLY HELP TO ERODE SOME OF THE
STRONG INVERSION...BUT MOISTURE WILL REMAIN FAIRLY SHALLOW...AND
WIDESPREAD PRECIPITATION IS NOT EXPECTED TO DEVELOP. THE CURRENT
RANGE OF POP VALUES (10-40 PERCENT FROM NORTH TO SOUTH) STILL
MATCHES FORECAST EXPECTATIONS NICELY...WITH TIMING REFINED BASED
ON 12Z RUNS...AND THE AREA SLIGHTLY EXPANDED. BECAUSE OF THE
INVERSION...THIS PRECIPITATION WILL LIKELY BE ALL RAIN...EVEN
THOUGH SURFACE TEMPERATURES EARLY MONDAY MORNING WILL BE IN THE
MID 30S.
SOME WEAK COLD ADVECTION BEHIND THE UPPER LOW WILL KEEP
TEMPERATURES IN THE MID 40S ON MONDAY...NEAR OR JUST ABOVE
NORMAL.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A COUPLE OF PROGRESSIVE S/WVS ARE FORECAST TO TRAVERSE FROM WEST TO
EAST ACROSS THE GREAT LAKES AND OHIO VALLEY REGION DURING THE EARLY
TO MID WEEK PERIOD. TUESDAY/S DISTURBANCE IS EXPECTED TO BE WEAK AND
MOISTURE STARVED...SO ONLY CLOUDS ARE FORECAST. THE SECOND
DISTURBANCE FOR WEDNESDAY/WEDNESDAY NIGHT IS A LITTLE STRONGER AND
HAS DEEPER MOISTURE IN ASSOCIATION WITH A COLD FRONT. HAVE CONTINUE
WITH A CHANCE OF SHOWERS DURING THIS TIME FRAME.
THE FORECAST BECOMES LESS CLEAR AS WE HEAD INTO THE END OF THE
WEEK...ESPECIALLY IN REGARDS TO AREAL COVERAGE AND PROBABILITY OF
PCPN. THE FLOW DOES BECOME MORE AMPLIFIED WITH A LARGE SCALE MID
LEVEL TROUGH DIGGING OUT ACROSS THE WESTERN U.S. AND RIDGING
DEVELOPING OVER THE EASTERN U.S. S/WV ENERGY FOR THURSDAY/FRIDAY
VARIOUS AMONGST THE MODELS IN TERMS OF HOW STRONG/DEEP IT WILL BE AS
IT PASSES THROUGH THE GREAT LAKES. HAVE KEPT POPS ON THE LOW SIDE
DUE TO HIGH UNCERTAINTY. FOR SATURDAY...LOOKS LIKE MID LEVEL RIDGING
AND A WARM FRONT WILL LIFT THROUGH OUR REGION. WARMER TEMPERATURES
AND SOME WAA SHOWERS WILL BE POSSIBLE.
IT WILL CONTINUE TO BE WARMER THAN NORMAL THROUGH THE PERIOD WITH
TEMPERATURES WARMING INTO THE UPPER 50S TO THE LOWER 60S BY THE
WEEKEND...WHICH IS SOME 20 DEGREES ABOVE NORMAL FOR MID DECEMBER.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
LIFR CONDITIONS IN FOG AND FREEZING FOG WILL RAPIDLY BECOME VFR
THIS AFTERNOON WITH NO CIG AND PATCHY MVFR VSBYS THROUGH ABOUT
20Z. EXPECT THE FOG TO MAKE ANOTHER APPEARANCE TONIGHT AS THE
TEMPERATURE INVERSION PERMITS MOISTURE TO BE TRAPPED IN AN EVEN
SHALLOWER LAYER TONIGHT. WHILE LAYER MAY BE MUCH MORE
SHALLOW...THIS WILL JUST MEAN THAT THE FOG THAT DEVELOPS TONIGHT
WILL BE QUICKER TO DISSIPATE TOMORROW. IT SHOULD BE JUST AS DENSE
GIVEN THAT THE WIND FIELDS WILL NOT BE SUBSTANTIAL TO SCOUR OUT
ANY LOW LEVEL MOISTURE.
OUTLOOK...MVFR CEILINGS POSSIBLE SUNDAY NIGHT INTO MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...HICKMAN
AVIATION...FRANKS/NOVAK
AREA FORECAST DISCUSSION...
NWS PORTLAND OR
850 PM PST FRI DEC 4 2015
.SYNOPSIS...THE NEXT MOIST FRONTAL SYSTEM AFFECTS THE REGION
TOMORROW. THE FRONT IS EXPECTED TO AFFECT MOSTLY THE NORTH COAST AND
COASTAL MOUNTAINS ON SATURDAY...THEN SWING INLAND AS A COLD FRONT
LATE SATURDAY INTO SUNDAY FOR ANOTHER ROUND OF SIGNIFICANT RAINS AND
COASTAL WINDS. A MORE SIGNIFICANT AND WETTER FRONT IS EXPECTED
SUNDAY NIGHT INTO MONDAY...WHICH WILL BRING MORE STRONG COASTAL
WINDS AND MAY BRING POTENTIAL FOR SOME FLOODING ON AREA RIVERS AND
STREAMS. AN ADDITIONAL VERY WET SYSTEM IS EXPECTED TOWARD THE MIDDLE
OF NEXT WEEK AS THIS MILD AND VERY WET PATTERN CONTINUES.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...WATER VAPOR SATELLITE IMAGERY
REVEALS A SHORTWAVE RIDGE TEMPORARILY SHIFTING OVER THE PACIFIC
NORTHWEST...WHILE A WARM FRONT IS ALREADY BEGINNING TO SPREAD HIGH
CLOUDS OVER THE REGION. CLOSER TO THE SURFACE...DOPPLER RADAR SHOWS A
FEW SHOWERS CONTINUE TO DRIFT NORTHEASTWARD ACROSS THE REGION...AND
ARE INCREASINGLY BECOMING CONFINED TO THE COAST AND HIGHER TERRAIN.
WITH THE LOWER ATMOSPHERE STABILIZING OVERNIGHT...EXPECT THE GENERAL
TREND OF DECREASING SHOWERS TO CONTINUE. THE 00Z SLE SOUNDING
MEASURED A WET BULB ZERO HEIGHT OF 3700 FT SO ANY SHOWERS IN THE
HIGHER TERRAIN WILL LIKELY ALLOW LIGHT SNOW TO ACCUMULATE ON CASCADE
PASSES.
MODELS REMAIN IN GOOD AGREEMENT THAT THE AFOREMENTIONED WARM FRONT
CURRENTLY SPREADING HIGH CLOUDS OVER THE REGION WILL CONTINUE
EASTWARD OVERNIGHT AND SPREAD STEADY RAIN ACROSS MUCH OF NORTHWEST
OREGON AND SOUTHWEST WASHINGTON LATE TONIGHT AND EARLY SATURDAY.
LATEST HRRR GUIDANCE SUGGESTS RAIN WILL SPREAD ONTO THE COAST BETWEEN
3 AND 5 AM AND INTO THE WILLAMETTE VALLEY BETWEEN 6 AND 8 AM. WHILE
POPS WERE INCREASED FOR INTERIOR LOCATIONS...GLOBAL MODELS REMAIN
LESS AMBITIOUS WITH RAIN CHANCES FOR LATE TONIGHT AND SATURDAY
MORNING SO POPS WERE GENERALLY HELD IN THE HIGH END CHANCE TO LOW END
LIKELY RANGE FOR THE WILLAMETTE VALLEY EVEN THOUGH THE HRRR WOULD
SUGGEST MOST OF THE REGION WILL SEE A WET START TO SATURDAY.
EAST TO WEST PRESSURE GRADIENTS WILL INCREASE NOTABLY ACROSS THE
REGION LATER TONIGHT AND SATURDAY. THIS SHOULD RESULT IN EASTERLY
WINDS PICKING UP ONCE AGAIN IN THE WESTERN COLUMBIA RIVER GORGE WITH
GUSTS OF AT LEAST 30 TO 50 MPH SATURDAY. THIS WILL ALSO ALLOW SNOW
LEVELS TO HANG NEAR THE CURRENT LEVEL OF 3500 TO 4000 FT ACROSS THE
SOUTH WASHINGTON CASCADES AND FAR NORTH OREGON CASCADES INTO SATURDAY
MORNING. WHILE QPF STILL DOES NOT LOOK IMPRESSIVE TOMORROW...WE MAY
SEE AN INCH OR TWO OF SNOW...POSSIBLY A BIT MORE IN THE SOUTH
WASHINGTON CASCADES...IN THE MORNING BEFORE THE BULK OF THE WARM
FRONTAL PRECIPITATION PUSHES NORTH OF OUR HIGHER TERRAIN AND WARMER
TEMPERATURES ALOFT ALLOW SNOW LEVELS TO RISE INTO THE 5500 TO 6500 FT
RANGE SATURDAY AFTERNOON/NIGHT. GIVEN THE OFFSHORE PRESSURE
GRADIENTS...SUSPECT THE COLDER WILL BE A BIT MORE STUBBORN TO EXIT
THAN PREVIOUSLY THOUGHT FOR LOCATIONS EAST AND NORTH OF MOUNT HOOD.
MEANWHILE...A TRAILING COLD FRONT ORIENTED FROM SOUTHWEST TO
NORTHEAST WILL SLOWLY DRIFT EASTWARD TOWARDS THE COAST
SATURDAY...BEFORE PUSHING ASHORE LATE SATURDAY NIGHT. THE MAIN STORY
WITH THIS SYSTEM WILL BE THE STRONG SOUTH WINDS THAT DEVELOP OUT
AHEAD OF IT ALONG THE OREGON AND WASHINGTON COASTS. MODELS AGREE 65
TO 75KT 925 MB SOUTH WINDS WILL DEVELOP OFF THE OREGON COAST SATURDAY
MORNING AND CONTINUE THROUGH MUCH OF SATURDAY NIGHT. THIS HAS BROUGHT
CONCERN THAT HIGH WINDS MAY SURFACE ALONG THE COAST...BUT GIVEN
PRESSURE GRADIENTS REMAIN SOLIDLY OFFSHORE SATURDAY AND EVEN MOST OF
SATURDAY NIGHT...SUSPECT MANY LOCATIONS WILL EXPERIENCE WIND GUSTS OF
50 MPH OR LESS. HOWEVER...CANNOT RULE OUT A FEW OF THE HEADLANDS LIKE
CAPE DISAPPOINTMENT AND CAPE MEARES GUSTING AROUND 60 MPH OR POSSIBLY
HIGHER...BUT SUSPECT THIS MAY END UP MORE THE EXCEPTION THAN THE
RULE AT THIS POINT. THE MOST FAVORABLE TIME FOR HIGHER WINDS TO
SURFACE ALONG THE COAST WILL LIKELY BE SATURDAY EVENING. IN
ADDITION...THIS SYSTEM WILL BRING A ROUND OF SOLID RAIN TO THE
REGION SATURDAY NIGHT...ON THE ORDER OF A QUARTER TO HALF AN INCH TO
THE WILLAMETTE VALLEY...AND 1 TO 2 INCHES OF RAIN FOR COASTAL AREAS
AND HIGHER TERRAIN. SNOW LEVELS WILL FALL BEHIND THE FRONT INTO THE
4500 FT AND 5500 FT RANGE SUNDAY...BUT DECREASING SHOWERS ON SUNDAY
SHOULD KEEP SNOW ACCUMULATIONS ACROSS THE HIGHER CASCADES FAIRLY
LIGHT.
THE BIGGER WEATHER STORY WILL ARRIVE SUNDAY NIGHT AND EARLY MONDAY AS
A MORE POTENT FRONT LIKELY PUSHES SOUTHEASTWARD ACROSS THE REGION.
AMAZINGLY...THIS STORM SYSTEM IS STILL SOUTH OF THE WESTERN PORTION
OF THE ALEUTIAN ISLANDS. WHILE WINDS ALOFT WITH THE SUNDAY
NIGHT/EARLY MONDAY STORM SYSTEM WILL LIKELY BE SIMILAR TO THE
SATURDAY/SATURDAY NIGHT STORM SYSTEM...APPROXIMATELY 75KT AT
925MB...PRESSURE GRADIENTS APPEAR MUCH MORE FAVORABLE FOR STRONGER
WINDS TO MIX DOWN TO THE SURFACE ALONG THE COAST AND IN THE COAST
RANGE. HIGH WIND PRODUCTS WILL LIKELY BE NEEDED. THERE MAY EVEN BE A
PERIOD OF BREEZY SOUTH WINDS EARLY MONDAY IN THE WILLAMETTE VALLEY
ALTHOUGH THE PORTLAND METRO MAY END UP BATTLING EAST WINDS. IN
ADDITION...MODELS DEPICT 850-1000MB IVT VALUES IN THE 250-300 G/KGS
RANGE WITH AN ORIENTATION MORE PERPENDICULAR THAN PARALLEL TO THE
COASTLINE. THIS SHOULD RESULT IN A 9-15 HOUR PERIOD OF STEADY RAIN
ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON DURING THIS TIME
WITH SOME LOCATIONS IN THE COAST RANGE AND CASCADES LIKELY RECEIVING
AT LEAST 4 TO 7 INCHES OF RAIN. WHILE NAEFS RETURN INTERVAL GUIDANCE
SUGGESTS IVT VALUES WITH THIS STORM SYSTEM OCCUR ON AVERAGE ABOUT
ONCE EVERY OTHER YEAR TO EVERY COUPLE OF YEARS...IT ALSO SUGGESTS
ANOTHER COMPARABLE STORM SYSTEM MAY ARRIVE MIDWEEK...WHICH MAY RESULT
IN SOME FLOOD CONCERNS. GIVEN THIS IS AN ENSEMBLE BASED APPROACH...IT
CERTAINLY BRINGS SOME PAUSE...AS WELL AS CONFIDENCE THAT WE ARE IN
STORE FOR A PERIOD OF NOTABLE WET WEATHER. THE CURRENT HYDROLOGIC
OUTLOOK COVERS THIS WELL. /NEUMAN
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY. ACTIVE WEATHER PATTERN
CONTINUES INTO NEXT WEEK. WE GET SOMEWHAT OF A BREAK MONDAY NIGHT
INTO TUESDAY...WITH ONLY A FEW SHOWERS STILL LINGERING AROUND THE
AREA. DURING THIS TIME THE MOISTURE PLUME FROM THE MONDAY SYSTEM
SHIFTS NORTH OF OUR AREA...BEFORE DROPPING BACK SOUTH WITH THE NEXT
LOW PRESSURE SYSTEM TUESDAY AFTERNOON INTO WEDNESDAY. THE MODELS
HAVE A LOT OF MOISTURE WITH BOTH OF THESE SYSTEMS...SO WE ARE
ANTICIPATING A VERY WET WEEK WITH SIGNIFICANT ACCUMULATIONS LIKELY
THROUGH WEDNESDAY. DUE TO THE TROPICAL AIRMASS SOURCING THE MOISTURE
FOR THESE SYSTEMS...SNOW LEVELS REMAIN UP ABOVE 7000 FT THROUGH THE
FIRST HALF OF NEXT WEEK. SNOW LEVELS DROP BACK DOWN TO BELOW PASS
LEVELS BEHIND THE TUESDAY-WEDNESDAY SYSTEM...WITH ACTIVE WEATHER
PATTERN CONTINUING INTO THE WEEKEND. THEREFORE...SNOW COULD IMPACT
TRAVEL THROUGH THE CASCADES STARTING WEDNESDAY AFTERNOON THROUGH THE
END OF THE WEEK. THE SYSTEMS LATER IN THE WEEK DON`T HAVE THE LONG
MOISTURE FETCH LIKE THE MONDAY-WEDNESDAY SYSTEMS...SO RAINFALL
AMOUNTS SHOULD BE LESS LATER IN THE WEEK. -MCCOY
&&
.AVIATION...PRIMARILY VFR CONDITIONS TONIGHT. THERE IS A SMALL
CHANCE FOR MVFR OR IFR CONDITIONS IN PATCHY FOG LATE IN THE NIGHT
AFTER 07Z. PREVAILING CIGS LATER TONIGHT...AFTER 11Z...WILL BEGIN TO
COME DOWN INTO THE LOW END OF VFR CATEGORY AS THE NEXT FRONTAL
SYSTEM APPROACHES. CONDITIONS EXPECTED TO REMAIN VFR THROUGH THE
DAY...BUT THERE IS A CHANCE FOR COASTAL AREAS TO SEE TEMPORARY MVFR
CONDITIONS.
KPDX AND APPROACHES...GENERALLY VFR CONDITIONS AT KPDX THROUGH THE
DAY SAT.
&&
.MARINE...A STRONG FRONTAL SYSTEM WILL GENERATE STORM FORCE WINDS
OVER THE WATERS LATE TONIGHT THROUGH SATURDAY. INCREASING SOUTH
WINDS WILL BUILD WIND WAVES AND A FRESH SOUTH SWELL WITH COMBINED
SEAS REACHING 20 FT BY SUNRISE SATURDAY. SEAS ARE EXPECTED TO BUILD
TO 20 TO 24 FT RANGE SATURDAY AFTERNOON. SOUTH WINDS WILL DECREASE
LATE SATURDAY NIGHT AND BE BELOW 25 KT BY SUNRISE SUNDAY.
THE SEAS WILL BRIEFLY DIP BACK INTO THE TEENS SUNDAY BEFORE A LARGE
WEST SWELL BUILDS SUNDAY EVENING. THIS SWELL WILL BRING SEAS BACK
ABOVE 20 FT SUNDAY EVENING. MODELS FORECAST THE SWELL TO PEAK AROUND
21 FT AT 17 SECONDS LATE SUNDAY NIGHT. THIS SWELL WILL GENERATE
LARGE AND DANGEROUS BREAKING WAVES IN THE SURF ZONE THROUGH MONDAY
MORNING. THE LARGE WESTERLY SWELL COINCIDES WITH ANOTHER ROUND OF
STRONG WINDS SUN NIGHT AND MONDAY AS THE NEXT FRONT MOVES IN.
THE LARGE S SWELL COUPLED WITH LARGE LOCALLY GENERATED WIND WAVES AND
FRESH SOUTHERLY SWELL WILL MAKE FOR CHAOTIC AND DANGEROUS SEAS.
THERE IS ANOTHER CHANCE FOR GALES OR STORM FORCE WINDS TUESDAY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...HIGH WIND WARNING FROM 10 AM SATURDAY TO 2 AM PST SUNDAY FOR
CENTRAL OREGON COAST-NORTH OREGON COAST.
HIGH SURF ADVISORY FROM 7 PM SUNDAY TO 9 AM PST MONDAY FOR
CENTRAL OREGON COAST-NORTH OREGON COAST.
WA...HIGH WIND WARNING FROM 10 AM SATURDAY TO 2 AM PST SUNDAY FOR
SOUTH WASHINGTON COAST.
HIGH SURF ADVISORY FROM 7 PM SUNDAY TO 9 AM PST MONDAY FOR
SOUTH WASHINGTON COAST.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 2 AM PST SATURDAY FOR
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO
60 NM.
STORM WARNING FROM 2 AM SATURDAY TO 2 AM PST SUNDAY FOR WATERS
FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10 TO 60 NM-
WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 AM PST SATURDAY
FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM
10 TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10
TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
6 PM PST SATURDAY.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 AM PST SATURDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
OUT 10 NM-COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR
OUT 10 NM.
STORM WARNING FROM 6 AM SATURDAY TO 2 AM PST SUNDAY FOR COASTAL
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 10 NM-
COASTAL WATERS FROM CASCADE HEAD TO FLORENCE OR OUT 10 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM PST SATURDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD
OR OUT 10 NM-COASTAL WATERS FROM CASCADE HEAD TO FLORENCE
OR OUT 10 NM.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1018 PM EST SUN DEC 6 2015
.SYNOPSIS...
AN UPPER LEVEL LOW DROPPING SE FROM THE OHIO VLY MAY BRING
A FEW SHOWERS TO SOUTHERN PA ON MONDAY. ANOTHER UPPER LEVEL
LOW MOVING ACROSS THE GREAT LAKES ON WED MAY BRING A FEW MORE
SHOWERS TO THE AREA LATER WED INTO THU. OTHERWISE HIGH PRESSURE
OVER THE SE STATES WILL KEEP DRY AND MILD CONDITIONS ACROSS
THE KEYSTONE STATE THIS WEEK. HIGH TEMPERATURES WILL AVERAGE
WELL ABOVE NORMAL FOR EARLY DEC.
&&
.NEAR TERM /UNTIL 10 AM MONDAY MORNING/...
10 PM UPDATE...
FOG IS FORMING AS FCST. IT IS DENSE IN THE ADVY AREA ALREADY AND
MAY EXPAND. BUT WILL WAIT A BIT LONGER TO DECIDE IF THE NOT-
ADVISED AREAS WILL NEED ONE AS WELL. TEMPS ARE ABOVE FREEZING IN
THE LAURELS AND IN KBFD.
UPDATE: I DUG DEEPER AND DISCOVERED THAT CTP CAN INDEED ISSUE A
FREEZING FOG ADVY. HOWEVER...THE THREAT OF DENSE FOG IS CORRECT
AND I AM HITTING THE ICE THREAT HARD IN THE TEXT AND SOCIAL MEDIA.
TO KEEP CONFUSION TO A MINIMUM...WILL JUST KEEP IT AS A DENSE FOG
ADVY. IF THIS RECURRS TOMORROW NIGHT...WILL ASSESS THE THREATS
AND APPROPRIATE PRODUCTS/WORDING THEN.
7 PM UPDATE...
TWO CALLS NOW THAT INDICATE DENSE FOG IN LOW LYING AREAS OF HAPPY
VALLEY. AOO AND A FEW OTHER SITES HAVE ALSO SHOWN HINTS AT GOING
LOW ON THE VISBY. AT THIS POINT...ONLY KFIG IS AT 1/4SM...NONE ARE
BELOW THAT. HOWEVER...DEWPOINT DEPRESSIONS ARE ONLY 1-2F AT MANY
SITES. WILL GO AHEAD AND ISSUE A DENSE FOG ADVY FOR THE CENTRAL
COUNTIES...STARTING SMALL. CONFIDENCE IS STILL LOWER THAN
NECESSARY - BUT ALMOST THERE - THAT WE WOULD NEED THE SAME OVER
THE AREAS WHICH DRIED OUT BETTER/LONGER DURING THE DAY TODAY. WILL
START WITH THE PLACES THAT DID NOT CLEAR OR CLEARED FOR ONLY A
SHORT TIME.
5 PM UPDATE...
FOG AND STRATUS NEVER LEFT THE MID SUSQ AND LIKELY WILL NOT GO
AWAY IN THE NEXT 18HRS. VISBY OUT THE WINDOW AT LAST DAYLIGHT IS
ABOUT 3SM IN A THICK HAZE AND KUNV ONLY 1-2SM AWAY IS ONLY 1/8SM -
ACTUAL OBSERVER AT TOWER. FOG IS STARTING TO SHOW UP AGAIN IN THE
OBS AT MANY OF THE SITES WHICH DID CLEAR UP EARLIER TODAY.
BUT...LOOKS LIKE IT IS ALMOST CERTAIN THAT IT WILL RE-ESTABLISH
TONIGHT. THE HIGH CLOUDS SHOULD NOT SERIOUSLY AFFECT THE
BLYR...BUT THAT IS THE ONLY FACTOR IN THE MIX WHICH COULD BUST A
FOGGY FORECAST - IF IT STAYS MILDER. MAY NEED TO HOIST THE DENSE
FOG ADVY IN JUST A SHORT WHILE. WAITING FOR JUST A FEW MORE OBS TO
BE A LITTLE MORE CERTAIN. AGAIN...THE THREAT WILL PROBABLY BE A
COMBINATION OF REDUCED VISBY AND THE PRESENCE OF FREEZING FOG AND
POSSIBILITY OF AN ICY COATING. NOT REALLY A PRODUCT AVAILABLE TO
CENTRAL PA TO COVER THIS. SO WE CAN BASICALLY TRY TWO ROUTES-
EITHER USE A WINTER WX ADVY OR...LIKE WE HAD EARLIER...THE DENSE
FOG ADVY WITH LOTS OF ICY WORDS IN IT. TO KEEP IT CONSISTENT AND
ACCOUNT FOR THE FACT THAT THE ROADS MAY NOT BECOME ICY
EVERYWHERE...A DENSE FOG ADVY IS PROBABLY THE ROUTE TO CHOOSE
SHOULD WE NEED IT AGAIN.
PREV...
EXTREMELY STUBBORN FOG CONTINUES TO SLOWLY LIFT AND DISSIPATE OVER
THE CENTRAL MOUNTAIN VALLEYS EARLY THIS AFTERNOON. WARM ADVECTION
OVER THE COLD VALLEYS WHICH RADIATED EFFICIENTLY OVERNIGHT LED TO
SOME OF THE MOST PERSISTENT ICE FOG I`VE SEEN IN CENTRAL PA IN THE
PAST 15 YEARS. WHERE IT REMAINED FOGGY...TEMPERATURES REMAINED
BELOW FREEZING THIS MORNING...WHILE CLEAR AREAS WARMED THROUGH THE
40S AND IN SOME CASES INTO THE LOWER 50S (SOUTH CENTRAL
MOUNTAINS).
AS THE UPPER RIDGE AXIS BREAKS DOWN/ SWINGS EAST OF THE REGION
LATE TODAY AND TONIGHT...THIN CIRRUS WILL CONTINUE TO OVERSPREAD
THE EASTERN HALF OF CENTRAL PA...AS IT HAS OVER THE WEST. SFC HIGH
WEAKENS AND SHIFTS EAST OF PA TONIGHT...BUT IT REMAINS FAVORABLE
FOR PATCHY LATE NIGHT VALLEY FOG. MINS WILL BE MOSTLY IN THE MID
TO UPPER 20S ONCE AGAIN.
&&
.SHORT TERM /10 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
MOISTURE CHALLENGED UPPER TROF CRASHING INTO AND DISPLACING THE
EAST COAST UPPER RIDGE WILL MOVE OVER WESTERN AND CENTRAL PA ON
MONDAY...BRINGING CONSIDERABLE CLOUDINESS BUT LITTLE ELSE IN THE
WAY OF SENSIBLE WEATHER AFTER ANOTHER ROUND OF MORNING VALLEY FOG.
THINK THE ONLY AREA TO SEE SHOWERS FROM THIS SYSTEM WILL BE THE
LAUREL HIGHLANDS...AS BOUNDARY LAYER IS JUST TOO DRY TO SUPPORT
MUCH PRECIPITATION FARTHER EAST. CLOUDS WILL BE THICKEST OVER THE
LAUREL HIGHLANDS AS WELL...WITH MOSTLY CLOUDY SKIES SEEN THERE...
WHILE THE REMAINDER OF CENTRAL PA RANGES FROM P/S TO M/S. HIGHS
WILL BE FAIRLY UNIFORM...RANGING FROM THE UPPER 40S TO THE LOWER
50S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THE MAIN FORECAST STORY FOR THE EXTENDED PERIOD IS THE CONTINUED
MILD TEMPERATURES...AS ZONAL FLOW FLOODS THE CONUS WITH PACIFIC
AIR. NAEFS AND ECENS OUTPUT SHOWING A SERIES OF SFC LOWS TRACKING
NORTHWARD THRU THE GRT LKS LATE NEXT WEEK...AS ANOMALOUS UPPER
RIDGE BUILDS ALONG THE E COAST. HAVE INCLUDED A CHC OF SHRA ASSOC
WITH SHORTWAVE LIFTING UP THE OHIO VALLEY LATE WED/EARLY THU.
OTHERWISE...THE EXTENDED FCST APPEARS DRY AND INCREASINGLY WARM
BENEATH BUILDING RIDGE.
GEFS PLUME DATA AND ECEME MOS SUPPORT MIN TEMPS ABOVE FREEZING
ACROSS THE ENTIRE CWA THU-SAT AND MAX TEMPS AT LEAST 15F ABV
NORMAL.
MAIN CHANGE WAS TO EDGE TEMPS UP A LITTLE.
ALSO MORE FOG COULD FORM TUESDAY MORNING...AS SKIES CLEAR.
THUS I ADDED PATCHY FOG.
ICE FOG ON A LOT OF OBJECTS EARLY TODAY.
A BIG CHANGE FROM THE LAST 2 WINTERS...ENJOY THE GOOD WEATHER
WHILE IT LAST.
FOR NEXT WEEKEND...STILL MILD...BUT SOME CHC OF SHOWERS BY
SUNDAY. WENT WITH CHC POPS FOR NOW.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
THE BIGGEST FORECAST QUESTION OVERNIGHT IS FOG FORMATION. CURRENT
HRRR AND RAP RUNS DECREASE THE FOG THROUGH MOST OF THE CENTRAL PA
BY 09Z...HOWEVER GIVEN THE LOW DEWPOINT DEPRESSIONS...CALM WINDS
AN STRONG INVERSION EXPECT CENTRAL TAF SITES AOO...UNV...IPT TO
SEE IFR AND LOWER CIGS AND VSBYS OVERNIGHT UNTIL MORNING.
SOME OF THE RESTRICTIONS COULD BE PATCHY THROUGH THE FIRST HALF OF
THE OVERNIGHT HOURS BEFORE BECOMING ENTRENCHED AFTER 06Z. MAINLY VFR
CONDS WILL PREVAIL AT JST AND BFD...DUE TO THE DRY NW FLOW ALOFT.
FOG/MIST THROUGH THE LOWER SUSQ IS AN INTERESTING CONUNDRUM.
THOUGH SOME HIGH CLOUDS PERSIST...CALMING WINDS...DEWPOINT
DEPRESSIONS OF CURRENT 4 DEGREES OR LESS...SHOULD ALLOW FOR FOR
PATCHY FOG OVERNIGHT. MAIN RESTRICTIONS SHOULD BE MVFR THOUGH
CAN/T RULE OUT A PERIOD OF IFR VSBYS NEAR SUNRISE. THE FOG WILL
SLOWLY LIFT/DISSIPATE TOMORROW MORNING...THOUGH QUICKER THAN IT
DID TODAY. SO EXPECT.VFR TO RETURN BY 15Z MON AT ALL SITES.
MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS THE
AREA MONDAY...POTENTIALLY BRINGING RESTRICTIONS TO KJST LATER
MONDAY AND SPREADING INTO MAINLY THE SOUTHERN HALF OF THE STATE
MON NIGHT.
OUTLOOK...
MON-MON NIGHT...CHANCE FOR MVFR CONDITIONS IN -SHRA ACROSS THE
SOUTHERN HALF OF PENN.
TUE...NO SIG WX EXPECTED.
TUE NIGHT-WED NIGHT...CHANCE FOR MVFR CIGS.
THU-FRI...MVFR POSS NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM EST MONDAY FOR PAZ012-017>019-
025>028-034>036-041-045-046-049>053.
&&
$$
SYNOPSIS...MARTIN
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
855 PM EST SUN DEC 6 2015
.SYNOPSIS...
AN UPPER LEVEL LOW DROPPING SE FROM THE OHIO VLY MAY BRING
A FEW SHOWERS TO SOUTHERN PA ON MONDAY. ANOTHER UPPER LEVEL
LOW MOVING ACROSS THE GREAT LAKES ON WED MAY BRING A FEW MORE
SHOWERS TO THE AREA LATER WED INTO THU. OTHERWISE HIGH PRESSURE
OVER THE SE STATES WILL KEEP DRY AND MILD CONDITIONS ACROSS
THE KEYSTONE STATE THIS WEEK. HIGH TEMPERATURES WILL AVERAGE
WELL ABOVE NORMAL FOR EARLY DEC.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
7 PM UPDATE...
TWO CALLS NOW THAT INDICATE DENSE FOG IN LOW LYING AREAS OF HAPPY
VALLEY. AOO AND A FEW OTHER SITES HAVE ALSO SHOWN HINTS AT GOING
LOW ON THE VISBY. AT THIS POINT...ONLY KFIG IS AT 1/4SM...NONE ARE
BELOW THAT. HOWEVER...DEWPOINT DEPRESSIONS ARE ONLY 1-2F AT MANY
SITES. WILL GO AHEAD AND ISSUE A DENSE FOG ADVY FOR THE CENTRAL
COUNTIES...STARTING SMALL. CONFIDENCE IS STILL LOWER THAN
NECESSARY - BUT ALMOST THERE - THAT WE WOULD NEED THE SAME OVER
THE AREAS WHICH DRIED OUT BETTER/LONGER DURING THE DAY TODAY. WILL
START WITH THE PLACES THAT DID NOT CLEAR OR CLEARED FOR ONLY A
SHORT TIME.
5 PM UPDATE...
FOG AND STRATUS NEVER LEFT THE MID SUSQ AND LIKELY WILL NOT GO
AWAY IN THE NEXT 18HRS. VISBY OUT THE WINDOW AT LAST DAYLIGHT IS
ABOUT 3SM IN A THICK HAZE AND KUNV ONLY 1-2SM AWAY IS ONLY 1/8SM -
ACTUAL OBSERVER AT TOWER. FOG IS STARTING TO SHOW UP AGAIN IN THE
OBS AT MANY OF THE SITES WHICH DID CLEAR UP EARLIER TODAY.
BUT...LOOKS LIKE IT IS ALMOST CERTAIN THAT IT WILL RE-ESTABLISH
TONIGHT. THE HIGH CLOUDS SHOULD NOT SERIOUSLY AFFECT THE
BLYR...BUT THAT IS THE ONLY FACTOR IN THE MIX WHICH COULD BUST A
FOGGY FORECAST - IF IT STAYS MILDER. MAY NEED TO HOIST THE DENSE
FOG ADVY IN JUST A SHORT WHILE. WAITING FOR JUST A FEW MORE OBS TO
BE A LITTLE MORE CERTAIN. AGAIN...THE THREAT WILL PROBABLY BE A
COMBINATION OF REDUCED VISBY AND THE PRESENCE OF FREEZING FOG AND
POSSIBILITY OF AN ICY COATING. NOT REALLY A PRODUCT AVAILABLE TO
CENTRAL PA TO COVER THIS. SO WE CAN BASICALLY TRY TWO ROUTES-
EITHER USE A WINTER WX ADVY OR...LIKE WE HAD EARLIER...THE DENSE
FOG ADVY WITH LOTS OF ICY WORDS IN IT. TO KEEP IT CONSISTENT AND
ACCOUNT FOR THE FACT THAT THE ROADS MAY NOT BECOME ICY
EVERYWHERE...A DENSE FOG ADVY IS PROBABLY THE ROUTE TO CHOOSE
SHOULD WE NEED IT AGAIN.
PREV...
EXTREMELY STUBBORN FOG CONTINUES TO SLOWLY LIFT AND DISSIPATE OVER
THE CENTRAL MOUNTAIN VALLEYS EARLY THIS AFTERNOON. WARM ADVECTION
OVER THE COLD VALLEYS WHICH RADIATED EFFICIENTLY OVERNIGHT LED TO
SOME OF THE MOST PERSISTENT ICE FOG I`VE SEEN IN CENTRAL PA IN THE
PAST 15 YEARS. WHERE IT REMAINED FOGGY...TEMPERATURES REMAINED
BELOW FREEZING THIS MORNING...WHILE CLEAR AREAS WARMED THROUGH THE
40S AND IN SOME CASES INTO THE LOWER 50S (SOUTH CENTRAL
MOUNTAINS).
AS THE UPPER RIDGE AXIS BREAKS DOWN/ SWINGS EAST OF THE REGION
LATE TODAY AND TONIGHT...THIN CIRRUS WILL CONTINUE TO OVERSPREAD
THE EASTERN HALF OF CENTRAL PA...AS IT HAS OVER THE WEST. SFC HIGH
WEAKENS AND SHIFTS EAST OF PA TONIGHT...BUT IT REMAINS FAVORABLE
FOR PATCHY LATE NIGHT VALLEY FOG. MINS WILL BE MOSTLY IN THE MID
TO UPPER 20S ONCE AGAIN.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
MOISTURE CHALLENGED UPPER TROF CRASHING INTO AND DISPLACING THE
EAST COAST UPPER RIDGE WILL MOVE OVER WESTERN AND CENTRAL PA ON
MONDAY...BRINGING CONSIDERABLE CLOUDINESS BUT LITTLE ELSE IN THE
WAY OF SENSIBLE WEATHER AFTER ANOTHER ROUND OF MORNING VALLEY FOG.
THINK THE ONLY AREA TO SEE SHOWERS FROM THIS SYSTEM WILL BE THE
LAUREL HIGHLANDS...AS BOUNDARY LAYER IS JUST TOO DRY TO SUPPORT
MUCH PRECIPITATION FARTHER EAST. CLOUDS WILL BE THICKEST OVER THE
LAUREL HIGHLANDS AS WELL...WITH MOSTLY CLOUDY SKIES SEEN THERE...
WHILE THE REMAINDER OF CENTRAL PA RANGES FROM P/S TO M/S. HIGHS
WILL BE FAIRLY UNIFORM...RANGING FROM THE UPPER 40S TO THE LOWER
50S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THE MAIN FORECAST STORY FOR THE EXTENDED PERIOD IS THE CONTINUED
MILD TEMPERATURES...AS ZONAL FLOW FLOODS THE CONUS WITH PACIFIC
AIR. NAEFS AND ECENS OUTPUT SHOWING A SERIES OF SFC LOWS TRACKING
NORTHWARD THRU THE GRT LKS LATE NEXT WEEK...AS ANOMALOUS UPPER
RIDGE BUILDS ALONG THE E COAST. HAVE INCLUDED A CHC OF SHRA ASSOC
WITH SHORTWAVE LIFTING UP THE OHIO VALLEY LATE WED/EARLY THU.
OTHERWISE...THE EXTENDED FCST APPEARS DRY AND INCREASINGLY WARM
BENEATH BUILDING RIDGE.
GEFS PLUME DATA AND ECEME MOS SUPPORT MIN TEMPS ABOVE FREEZING
ACROSS THE ENTIRE CWA THU-SAT AND MAX TEMPS AT LEAST 15F ABV
NORMAL.
MAIN CHANGE WAS TO EDGE TEMPS UP A LITTLE.
ALSO MORE FOG COULD FORM TUESDAY MORNING...AS SKIES CLEAR.
THUS I ADDED PATCHY FOG.
ICE FOG ON A LOT OF OBJECTS EARLY TODAY.
A BIG CHANGE FROM THE LAST 2 WINTERS...ENJOY THE GOOD WEATHER
WHILE IT LAST.
FOR NEXT WEEKEND...STILL MILD...BUT SOME CHC OF SHOWERS BY
SUNDAY. WENT WITH CHC POPS FOR NOW.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
THE BIGGEST FORECAST QUESTION OVERNIGHT IS FOG FORMATION. CURRENT
HRRR AND RAP RUNS DECREASE THE FOG THROUGH MOST OF THE CENTRAL PA
BY 09Z...HOWEVER GIVEN THE LOW DEWPOINT DEPRESSIONS...CALM WINDS
AN STRONG INVERSION EXPECT CENTRAL TAF SITES AOO...UNV...IPT TO
SEE IFR AND LOWER CIGS AND VSBYS OVERNIGHT UNTIL MORNING.
SOME OF THE RESTRICTIONS COULD BE PATCHY THROUGH THE FIRST HALF OF
THE OVERNIGHT HOURS BEFORE BECOMING ENTRENCHED AFTER 06Z. MAINLY VFR
CONDS WILL PREVAIL AT JST AND BFD...DUE TO THE DRY NW FLOW ALOFT.
FOG/MIST THROUGH THE LOWER SUSQ IS AN INTERESTING CONUNDRUM.
THOUGH SOME HIGH CLOUDS PERSIST...CALMING WINDS...DEWPOINT
DEPRESSIONS OF CURRENT 4 DEGREES OR LESS...SHOULD ALLOW FOR FOR
PATCHY FOG OVERNIGHT. MAIN RESTRICTIONS SHOULD BE MVFR THOUGH
CAN/T RULE OUT A PERIOD OF IFR VSBYS NEAR SUNRISE. THE FOG WILL
SLOWLY LIFT/DISSIPATE TOMORROW MORNING...THOUGH QUICKER THAN IT
DID TODAY. SO EXPECT.VFR TO RETURN BY 15Z MON AT ALL SITES.
MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS THE
AREA MONDAY...POTENTIALLY BRINGING RESTRICTIONS TO KJST LATER
MONDAY AND SPREADING INTO MAINLY THE SOUTHERN HALF OF THE STATE
MON NIGHT.
OUTLOOK...
MON-MON NIGHT...CHANCE FOR MVFR CONDITIONS IN -SHRA ACROSS THE
SOUTHERN HALF OF PENN.
TUE...NO SIG WX EXPECTED.
TUE NIGHT-WED NIGHT...CHANCE FOR MVFR CIGS.
THU-FRI...MVFR POSS NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM EST MONDAY FOR PAZ012-017>019-
025>028-034>036-041-045-046-049>053.
&&
$$
SYNOPSIS...MARTIN
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
822 PM CST SUN DEC 6 2015
.UPDATE...
LATEST SATELLITE IMAGERY SHOWS LOW CLOUDS CONTINUE TO
INCREASE/SPREAD INTO THE MID STATE THIS EVENING AS A WELL-DEFINED
UPPER LOW MOVES ACROSS ILLINOIS. RADAR IMAGERY SHOWS ONLY A FEW
SHOWERS WELL TO OUR NORTH IN KENTUCKY...AND LATEST HRRR RUNS SHOW
LITTLE IF ANY SHOWERS DEVELOPING ACROSS NORTHERN PARTS OF THE CWA
OVERNIGHT. THUS WILL CUT BACK ON POPS FOR TONIGHT...WITH JUST
SLIGHT CHANCE OVER NORTHEAST ZONES. HAVE ALSO LOWERED MINS FOR
TONIGHT OVER SOUTHERN/EASTERN ZONES WHERE LACK OF CLOUDS HAS
ALLOWED TEMPERATURES TO ALREADY FALL TO NEAR FORECAST LOWS FOR
TONIGHT. UPDATED PRODUCTS OUT SHORTLY.
&&
.PREV DISCUSSION...
CONSIDERABLY MORE CLOUD COVER OUT THERE THIS AFTERNOON THAN WE HAVE
SEEN THE LAST COUPLE OF DAYS. LATEST VISIBLE SATELLITE SHOWS A
BREAK IN THOSE CLOUDS MOVING INTO AREAS WEST OF I-65...AND WHILE
THIS BREAK WILL MOVE EAST OF THE I-65 CORRIDOR LATER THIS AFTERNOON
AND EVENING...MORE CLOUDS WILL MOVE INTO THE MID-STATE TONIGHT. PART
OF AN UPPER LEVEL SYSTEM THAT WILL SCRAPE THE STATE...SOME LOW
CLOUDS WILL LIKELY TRAVERSE MIDDLE TN PRIOR TO DAYBREAK MONDAY. AS
FAR AS PRECIPITATION WITH THIS SYSTEM...I`M GOING TO MAINTAIN A VERY
SMALL CHANCE FOR THE NORTHEAST QUADRANT OF THE MID-STATE BUT THE AIR
IS VERY DRY OUT THERE /PER THE 12Z OHX SOUNDING/ SO I WOULDN`T
EXPECT ANY MORE THAN A SPRINKLE OR TWO NORTH AND EAST OF THE
NASHVILLE METRO AREA AFTER DARK.
ANOTHER SYSTEM VERY SIMILAR TO THE ONE TONIGHT MAY BRUSH THE MID-
STATE WEDNESDAY...BUT THE REAL FOCUS WILL BE THE SYSTEM BOTH MODELS
ARE DEPICTING NEXT WEEKEND. A VERY SHARP AND AMPLIFIED UPPER LEVEL
TROUGH IS BEING SHOWN TO MOVE ACROSS THE SOUTHERN HALF OF THE
CONUS...AND A RESULTANT SURFACE LOW COULD FINALLY BRING SOME
THUNDERSTORMS INTO THE REGION. THIS IS CURRENTLY BEING PROGGED AS A
VERY DYNAMIC SYSTEM. THIS INCLUDES AFTERNOON HIGHS AHEAD OF THE
SYSTEM 10-15 DEGREES ABOVE NORMAL...LOTS OF WIND SHEAR...AND 850MB
TEMPERATURES OF 12-14 DEGREES CELSIUS...ALL COMPONENTS OF AT LEAST
SOME STRONG STORMS. WHILE BOTH MODELS ARE SHOWING THESE COMPONENTS
IN THE SAME TIME FRAME...WILL RUN WITH 50 POP FOR NOW...WHICH IS
PRETTY HIGH FOR DAY 7-8 AS IT IS. THIS SYSTEM WILL BEAR WATCHING AS
WE MOVE THROUGH THE UPCOMING WEEK. EVEN IF STRONG STORMS DON`T REAR
THEIR HEAD...PW VALUES ON THE ORDER OF 1.5-1.6 INCHES WITH A 50 KT
LLJ MEANS SOME DECENT RAINFALL.
AVIATION...
00Z TAF DISCUSSION.
UPPER TROUGH MOVING THROUGH MID WEST AND CENTERED NEAR CHICAGO AT
2330Z. VORT LOBE ON SOUTH END EXTENDING DOWN ALONG MISSISSIPPI
RIVER WILL SWING ACROSS THE MID STATE OVERNIGHT SO LOOK FOR CLOUDS
TO INCREASE AND LOWER WITH A SPRINKLE OR TWO POSSIBLE NEAR
KENTUCKY BORDER AND IN THE UPPER CUMBERLAND LATER TONIGHT/EARLY
MONDAY. CEILINGS WILL IMPROVE FROM WEST TO EAST MID TO LATE
MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 44 55 37 57 / 10 10 0 0
CLARKSVILLE 41 53 35 56 / 10 10 0 0
CROSSVILLE 42 51 34 54 / 20 20 10 0
COLUMBIA 39 55 34 57 / 10 10 0 0
LAWRENCEBURG 39 55 34 58 / 10 10 0 0
WAVERLY 41 54 37 57 / 10 10 0 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION........BOYD/01
LONG TERM..................SHAMBURGER/55
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
958 AM CST SAT DEC 5 2015
.UPDATE...
LOW CLOUDS ARE SLOWER TO BURN OFF OUT WEST THEN WE PREVIOUSLY
ANTICIPATED. HAVE UPDATED TO KEEP CLOUDS FOR A FEW MORE HOURS.
HOURLY TEMPERATURES WERE RUNNING BEHIND WARMING...BUT THINK HIGHS
LOOK GOOD. THE REST OF THE FORECAST LOOKS ON TRACK.
&&
.PREV DISCUSSION... /ISSUED 539 AM CST SAT DEC 5 2015/
AVIATION.../12Z UPDATE/
VFR CONDITIONS ARE EXPECTED WITH LIGHT AND VARIABLE WINDS THROUGH
THIS FORECAST PERIOD. CIRRUS WILL MOVE ACROSS THE WESTERN PORTIONS
TODAY FROM TIME TO TIME. KDRT WILL LIKELY SEE MVFR CIGS THIS
MORNING THROUGH 17Z. CIRRUS ACROSS THIS AREA IS CURRENTLY NOT
ALLOWING WIDESPREAD LOW CLOUD DEVELOPMENT. DO THINK LOW CLOUDS
SHOULD DEVELOP IN THE NEXT FEW HOURS. WILL CONTINUE TO MONITOR THE
TRENDS FOR FURTHER UPDATES. WINDS AT KDRT WILL BECOME SE AT 10-15
MPH AFTER 17Z THEN BACK TO EASTERLY AFTER 01Z AT 5-10 KNOTS.
PREV DISCUSSION... /ISSUED 332 AM CST SAT DEC 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
COOL MORNINGS WITH PLEASANT AFTERNOON TEMPERATURES EXPECTED TODAY
AND SUNDAY WITH SOME CLOUDS MIXED IN ACROSS THE RIO GRANDE VALLEY.
TEMPERATURES WILL RETURN TO NEAR AND SLIGHTLY ABOVE NORMAL SUNDAY
WITH HIGHS REACHING INTO THE MID TO UPPER 60S.
WATER VAPOR AND RAP ANALYSIS DEPICT A WEAK SHORTWAVE RIDGE OVER
TEXAS AND THE GULF COASTAL WATERS THAT IS ALLOWING FOR WEAK
MOISTURE RETURN IN THE 925-700MB LAYER. THE MAIN WEAK MOISTURE
TONGUE IS CONFINED TO THE RIO GRANDE VALLEY AS IT POOLS AGAINST
THE SIERRA DEL BURRO RANGE. AS A RESULT...EXPECT LOW CLOUDS TO
DEVELOP THROUGH THE MORNING HOURS ACROSS THE RIO GRANDE VALLEY
THAT WILL SLOWLY BREAK UP THROUGH THE DAY. LOCATIONS EAST OF U.S.
HIGHWAY 83 WILL REMAIN MOSTLY SUNNY WITH ONLY HIGH CLOUDS
STREAMING OVERHEAD. AREAS SEEING MORE CLOUDS OUT WEST WILL NOT
WARM AS MUCH AS CENTRAL AND EAST LOCATIONS WITH A NICE REBOUND INTO
THE LOW TO MID 60S EXPECTED TODAY. MAVMOS ALONG WITH SUPPORT FROM
RAW MODEL SOUNDING GUIDANCE APPEARS TO BE THE BEST ROUTE FOR
MAXIMUM HIGHS TODAY. MIXING HEIGHTS WILL TOP OUT NEAR 2-2.2KFT
NEAR 9-10C THAT WILL SUPPORT THESE HIGHER VALUES VS. THE SLIGHTLY
COOLER MET/ECSMOS. DID TRIM 1F DEGREE OFF MAX HIGHS FOR KDRT
GIVEN THE CLOUD INTERFERENCE THROUGH AT LEAST THE LATE MORNING.
EXPECT A NEAR COPY FOR SUNDAY WITH SOME MORNING CLOUDS ACROSS THE
RIO GRANDE VALLEY AGAIN AND TEMPERATURES AREAWIDE LIKELY 1-3F
DEGREES WARMER IN THE AFTERNOON. SOME LOCATIONS ACROSS THE COASTAL
PLAINS AND NEAR KSAT COULD PUSH THE 70F DEGREE MARK. A WEAK
DRYLINE WILL SHIFT THROUGH ON SUNDAY USHERING IN DRIER AIR WITH
N/NW WINDS AND ONLY LIMITED MID-LEVEL CLOUDS. NO COLD AIR IS
ASSOCIATED WITH THIS BOUNDARY AND THUS WE WILL CONTINUE TO WARM
THROUGH THE AFTERNOON DESPITE THE NORTH WINDS.
LONG TERM (MONDAY THROUGH FRIDAY)...
NO HAZARDS APPEAR LIKELY THROUGH THE LONG TERM WITH PLEASANT AND
ABOVE NORMAL TEMPERATURES EXPECTED THROUGH AT LEAST THURSDAY. RAIN
CHANCES WILL INCREASE GOING INTO NEXT SATURDAY AHEAD OF A STRONGER
COLD FRONT AND MID-LVL SYSTEM.
FROM EARLY NEXT WEEK TO MID WEEK...THE REGION WILL REMAIN SOUTH OF
THE ACTIVE JET STREAM AND VOID OF AIRMASS CHANGES. SURFACE HIGH
PRESSURE WILL REMAIN OVER THE NORTHERN GULF THROUGH MID-WEEK AND
WEAK SOUTHWEST FLOW ALOFT. PWATS WILL BE IN THE 0.4"-0.8" RANGE
AS WEAK SOUTH SURFACE WINDS ATTEMPT TO BRING HIGHER MOISTURE TO
THE REGION. BY THURSDAY...A STRONGER SHORTWAVE TROUGH ACROSS THE
CENTRAL PLAINS WILL PUSH A WEAK FRONT NEAR THE HILL COUNTRY BUT
ONLY LIMITED RAIN CHANCES FOR THE COASTAL PLAINS ARE EXPECTED
WHERE PWATS WILL RECOVER TOWARDS 1.3".
A MORE POWERFUL SYSTEM WILL APPROACH THE BIG BEND LATE FRIDAY
INTO THE WEEKEND THAT MAY AID IN SOME SCATTERED SHOWERS AND STORMS.
THE BEST DYNAMICS AND FORCING SILL APPEAR TO BE NORTH AND EAST
WHERE THE BETTER RAIN CHANCES WILL BE. PWAT RECOVER STILL APPEARS
LOW TO MODEST AT BEST AND WILL ADVERTISE 20-30% FOR NOW AND WATCH
THE MODEL EVOLUTION FOR THIS TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 65 42 67 40 66 / 0 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 64 39 66 37 65 / 0 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 66 41 67 40 67 / 0 0 0 0 0
BURNET MUNI AIRPORT 63 41 63 37 64 / 0 0 0 0 0
DEL RIO INTL AIRPORT 63 42 66 41 66 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 62 43 64 35 64 / 0 0 0 0 0
HONDO MUNI AIRPORT 65 40 68 38 66 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 64 40 66 40 65 / 0 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 65 43 67 42 66 / 0 0 0 0 0
SAN ANTONIO INTL AIRPORT 65 42 68 42 66 / 0 0 0 0 0
STINSON MUNI AIRPORT 66 43 69 42 67 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...RUNYEN
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...30
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
539 AM CST SAT DEC 5 2015
.AVIATION.../12Z UPDATE/
VFR CONDITIONS ARE EXPECTED WITH LIGHT AND VARIABLE WINDS THROUGH
THIS FORECAST PERIOD. CIRRUS WILL MOVE ACROSS THE WESTERN PORTIONS
TODAY FROM TIME TO TIME. KDRT WILL LIKELY SEE MVFR CIGS THIS
MORNING THROUGH 17Z. CIRRUS ACROSS THIS AREA IS CURRENTLY NOT
ALLOWING WIDESPREAD LOW CLOUD DEVELOPMENT. DO THINK LOW CLOUDS
SHOULD DEVELOP IN THE NEXT FEW HOURS. WILL CONTINUE TO MONITOR THE
TRENDS FOR FURTHER UPDATES. WINDS AT KDRT WILL BECOME SE AT 10-15
MPH AFTER 17Z THEN BACK TO EASTERLY AFTER 01Z AT 5-10 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 332 AM CST SAT DEC 5 2015/
SHORT TERM (TODAY THROUGH SUNDAY)...
COOL MORNINGS WITH PLEASANT AFTERNOON TEMPERATURES EXPECTED TODAY
AND SUNDAY WITH SOME CLOUDS MIXED IN ACROSS THE RIO GRANDE VALLEY.
TEMPERATURES WILL RETURN TO NEAR AND SLIGHTLY ABOVE NORMAL SUNDAY
WITH HIGHS REACHING INTO THE MID TO UPPER 60S.
WATER VAPOR AND RAP ANALYSIS DEPICT A WEAK SHORTWAVE RIDGE OVER
TEXAS AND THE GULF COASTAL WATERS THAT IS ALLOWING FOR WEAK
MOISTURE RETURN IN THE 925-700MB LAYER. THE MAIN WEAK MOISTURE
TONGUE IS CONFINED TO THE RIO GRANDE VALLEY AS IT POOLS AGAINST
THE SIERRA DEL BURRO RANGE. AS A RESULT...EXPECT LOW CLOUDS TO
DEVELOP THROUGH THE MORNING HOURS ACROSS THE RIO GRANDE VALLEY
THAT WILL SLOWLY BREAK UP THROUGH THE DAY. LOCATIONS EAST OF U.S.
HIGHWAY 83 WILL REMAIN MOSTLY SUNNY WITH ONLY HIGH CLOUDS
STREAMING OVERHEAD. AREAS SEEING MORE CLOUDS OUT WEST WILL NOT
WARM AS MUCH AS CENTRAL AND EAST LOCATIONS WITH A NICE REBOUND INTO
THE LOW TO MID 60S EXPECTED TODAY. MAVMOS ALONG WITH SUPPORT FROM
RAW MODEL SOUNDING GUIDANCE APPEARS TO BE THE BEST ROUTE FOR
MAXIMUM HIGHS TODAY. MIXING HEIGHTS WILL TOP OUT NEAR 2-2.2KFT
NEAR 9-10C THAT WILL SUPPORT THESE HIGHER VALUES VS. THE SLIGHTLY
COOLER MET/ECSMOS. DID TRIM 1F DEGREE OFF MAX HIGHS FOR KDRT
GIVEN THE CLOUD INTERFERENCE THROUGH AT LEAST THE LATE MORNING.
EXPECT A NEAR COPY FOR SUNDAY WITH SOME MORNING CLOUDS ACROSS THE
RIO GRANDE VALLEY AGAIN AND TEMPERATURES AREAWIDE LIKELY 1-3F
DEGREES WARMER IN THE AFTERNOON. SOME LOCATIONS ACROSS THE COASTAL
PLAINS AND NEAR KSAT COULD PUSH THE 70F DEGREE MARK. A WEAK
DRYLINE WILL SHIFT THROUGH ON SUNDAY USHERING IN DRIER AIR WITH
N/NW WINDS AND ONLY LIMITED MID-LEVEL CLOUDS. NO COLD AIR IS
ASSOCIATED WITH THIS BOUNDARY AND THUS WE WILL CONTINUE TO WARM
THROUGH THE AFTERNOON DESPITE THE NORTH WINDS.
LONG TERM (MONDAY THROUGH FRIDAY)...
NO HAZARDS APPEAR LIKELY THROUGH THE LONG TERM WITH PLEASANT AND
ABOVE NORMAL TEMPERATURES EXPECTED THROUGH AT LEAST THURSDAY. RAIN
CHANCES WILL INCREASE GOING INTO NEXT SATURDAY AHEAD OF A STRONGER
COLD FRONT AND MID-LVL SYSTEM.
FROM EARLY NEXT WEEK TO MID WEEK...THE REGION WILL REMAIN SOUTH OF
THE ACTIVE JET STREAM AND VOID OF AIRMASS CHANGES. SURFACE HIGH
PRESSURE WILL REMAIN OVER THE NORTHERN GULF THROUGH MID-WEEK AND
WEAK SOUTHWEST FLOW ALOFT. PWATS WILL BE IN THE 0.4"-0.8" RANGE
AS WEAK SOUTH SURFACE WINDS ATTEMPT TO BRING HIGHER MOISTURE TO
THE REGION. BY THURSDAY...A STRONGER SHORTWAVE TROUGH ACROSS THE
CENTRAL PLAINS WILL PUSH A WEAK FRONT NEAR THE HILL COUNTRY BUT
ONLY LIMITED RAIN CHANCES FOR THE COASTAL PLAINS ARE EXPECTED
WHERE PWATS WILL RECOVER TOWARDS 1.3".
A MORE POWERFUL SYSTEM WILL APPROACH THE BIG BEND LATE FRIDAY
INTO THE WEEKEND THAT MAY AID IN SOME SCATTERED SHOWERS AND STORMS.
THE BEST DYNAMICS AND FORCING SILL APPEAR TO BE NORTH AND EAST
WHERE THE BETTER RAIN CHANCES WILL BE. PWAT RECOVER STILL APPEARS
LOW TO MODEST AT BEST AND WILL ADVERTISE 20-30% FOR NOW AND WATCH
THE MODEL EVOLUTION FOR THIS TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 65 42 67 40 66 / 0 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 64 39 66 37 65 / 0 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 66 41 67 40 67 / 0 0 0 0 0
BURNET MUNI AIRPORT 63 41 63 37 64 / 0 0 0 0 0
DEL RIO INTL AIRPORT 63 42 66 41 66 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 62 43 64 35 64 / 0 0 0 0 0
HONDO MUNI AIRPORT 65 40 68 38 66 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 64 40 66 40 65 / 0 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 65 43 67 42 66 / 0 0 0 0 0
SAN ANTONIO INTL AIRPORT 65 42 68 42 66 / 0 0 0 0 0
STINSON MUNI AIRPORT 66 43 69 42 67 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...10
SYNOPTIC/GRIDS...ALLEN
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
332 AM CST SAT DEC 5 2015
.SHORT TERM (TODAY THROUGH SUNDAY)...
COOL MORNINGS WITH PLEASANT AFTERNOON TEMPERATURES EXPECTED TODAY
AND SUNDAY WITH SOME CLOUDS MIXED IN ACROSS THE RIO GRANDE VALLEY.
TEMPERATURES WILL RETURN TO NEAR AND SLIGHTLY ABOVE NORMAL SUNDAY
WITH HIGHS REACHING INTO THE MID TO UPPER 60S.
WATER VAPOR AND RAP ANALYSIS DEPICT A WEAK SHORTWAVE RIDGE OVER
TEXAS AND THE GULF COASTAL WATERS THAT IS ALLOWING FOR WEAK
MOISTURE RETURN IN THE 925-700MB LAYER. THE MAIN WEAK MOISTURE
TONGUE IS CONFINED TO THE RIO GRANDE VALLEY AS IT POOLS AGAINST
THE SIERRA DEL BURRO RANGE. AS A RESULT...EXPECT LOW CLOUDS TO
DEVELOP THROUGH THE MORNING HOURS ACROSS THE RIO GRANDE VALLEY
THAT WILL SLOWLY BREAK UP THROUGH THE DAY. LOCATIONS EAST OF U.S.
HIGHWAY 83 WILL REMAIN MOSTLY SUNNY WITH ONLY HIGH CLOUDS
STREAMING OVERHEAD. AREAS SEEING MORE CLOUDS OUT WEST WILL NOT
WARM AS MUCH AS CENTRAL AND EAST LOCATIONS WITH A NICE REBOUND INTO
THE LOW TO MID 60S EXPECTED TODAY. MAVMOS ALONG WITH SUPPORT FROM
RAW MODEL SOUNDING GUIDANCE APPEARS TO BE THE BEST ROUTE FOR
MAXIMUM HIGHS TODAY. MIXING HEIGHTS WILL TOP OUT NEAR 2-2.2KFT
NEAR 9-10C THAT WILL SUPPORT THESE HIGHER VALUES VS. THE SLIGHTLY
COOLER MET/ECSMOS. DID TRIM 1F DEGREE OFF MAX HIGHS FOR KDRT
GIVEN THE CLOUD INTERFERENCE THROUGH AT LEAST THE LATE MORNING.
EXPECT A NEAR COPY FOR SUNDAY WITH SOME MORNING CLOUDS ACROSS THE
RIO GRANDE VALLEY AGAIN AND TEMPERATURES AREAWIDE LIKELY 1-3F
DEGREES WARMER IN THE AFTERNOON. SOME LOCATIONS ACROSS THE COASTAL
PLAINS AND NEAR KSAT COULD PUSH THE 70F DEGREE MARK. A WEAK
DRYLINE WILL SHIFT THROUGH ON SUNDAY USHERING IN DRIER AIR WITH
N/NW WINDS AND ONLY LIMITED MID-LEVEL CLOUDS. NO COLD AIR IS
ASSOCIATED WITH THIS BOUNDARY AND THUS WE WILL CONTINUE TO WARM
THROUGH THE AFTERNOON DESPITE THE NORTH WINDS.
&&
.LONG TERM (MONDAY THROUGH FRIDAY)...
NO HAZARDS APPEAR LIKELY THROUGH THE LONG TERM WITH PLEASANT AND
ABOVE NORMAL TEMPERATURES EXPECTED THROUGH AT LEAST THURSDAY. RAIN
CHANCES WILL INCREASE GOING INTO NEXT SATURDAY AHEAD OF A STRONGER
COLD FRONT AND MID-LVL SYSTEM.
FROM EARLY NEXT WEEK TO MID WEEK...THE REGION WILL REMAIN SOUTH OF
THE ACTIVE JET STREAM AND VOID OF AIRMASS CHANGES. SURFACE HIGH
PRESSURE WILL REMAIN OVER THE NORTHERN GULF THROUGH MID-WEEK AND
WEAK SOUTHWEST FLOW ALOFT. PWATS WILL BE IN THE 0.4"-0.8" RANGE
AS WEAK SOUTH SURFACE WINDS ATTEMPT TO BRING HIGHER MOISTURE TO
THE REGION. BY THURSDAY...A STRONGER SHORTWAVE TROUGH ACROSS THE
CENTRAL PLAINS WILL PUSH A WEAK FRONT NEAR THE HILL COUNTRY BUT
ONLY LIMITED RAIN CHANCES FOR THE COASTAL PLAINS ARE EXPECTED
WHERE PWATS WILL RECOVER TOWARDS 1.3".
A MORE POWERFUL SYSTEM WILL APPROACH THE BIG BEND LATE FRIDAY
INTO THE WEEKEND THAT MAY AID IN SOME SCATTERED SHOWERS AND STORMS.
THE BEST DYNAMICS AND FORCING SILL APPEAR TO BE NORTH AND EAST
WHERE THE BETTER RAIN CHANCES WILL BE. PWAT RECOVER STILL APPEARS
LOW TO MODEST AT BEST AND WILL ADVERTISE 20-30% FOR NOW AND WATCH
THE MODEL EVOLUTION FOR THIS TIME FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 65 42 67 40 66 / 0 0 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 64 39 66 37 65 / 0 0 0 0 0
NEW BRAUNFELS MUNI AIRPORT 66 41 67 40 67 / 0 0 0 0 0
BURNET MUNI AIRPORT 63 41 63 37 64 / 0 0 0 0 0
DEL RIO INTL AIRPORT 63 42 66 41 66 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 62 43 64 35 64 / 0 0 0 0 0
HONDO MUNI AIRPORT 65 40 68 38 66 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 64 40 66 40 65 / 0 0 0 0 0
LA GRANGE - FAYETTE REGIONAL 65 43 67 42 66 / 0 0 0 0 0
SAN ANTONIO INTL AIRPORT 65 42 68 42 66 / 0 0 0 0 0
STINSON MUNI AIRPORT 66 43 69 42 67 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...10
SYNOPTIC/GRIDS...ALLEN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
422 AM EST MON DEC 7 2015
.SYNOPSIS...
ISSUED AT 421 AM EST MON DEC 7 2015
WIDESPREAD FOG WILL CONTINUE TO DEVELOP OVER MUCH OF NORTHERN
INDIANA AND FAR SOUTHWEST LOWER MICHIGAN AND EXTEND INTO NORTHWEST
OHIO. EARLY MORNING TEMPERATURES WILL RANGE FROM THE UPPER 20S TO
UPPER 30S WHERE CLOUDS LINGERED OVERNIGHT. THE NEXT CHANCE OF RAIN
WILL ARRIVE LATE TUESDAY INTO WEDNESDAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM EST MON DEC 7 2015
THE COMBINATION OF RADIATION FOG AND ADVECTION FOG WAS MAKING THE
FORECAST VERY CHALLENGING EARLY THIS MORNING. SKIES HAD CLEARED OVER
FAR SOUTHWEST LOWER MICHIGAN AND NORTHERN INDIANA WHERE RADIATIONAL
COOLING HAD ALLOWED FOG TO FORM. THE FOG WAS BECOMING MORE
WIDESPREAD AND BECOMING LOCALLY DENSE WITH VISIBILITIES AROUND OR
UNDER A QUARTER OF MILE. ADDITIONAL LOW CLOUDS AND SOME FOG WAS
SPREADING SOUTHEAST OVER LAKE MICHIGAN AND SHOULD SPREAD INTO FAR
SOUTHWEST LOWER MICHIGAN AND NORTHWEST INDIANA EARLY THIS MORNING.
HAVE ISSUED A DENSE FOG ADVISORY FOR ALL OF FAR SOUTHWEST LOWER
MICHIGAN AND NORTHWEST INDIANA...INTO THE NORTHERN PORTION OF
NORTHWEST OHIO. THE TEMPERATURE IN SOME SPOTS WILL BE COLD ENOUGH
FOR THE FOG TO BECOME FREEZING AND DEPOSIT A LIGHT FROST OR VERY
LIGHT ICE LAYER. GIVEN LIMITED INSOLATION AND VERY LIGHT FLOW
ALOFT...THE DENSE FOG WILL LIKELY PERSIST THROUGH MOST OF THE
MORNING. OTHERWISE...CONDITIONS WILL IMPROVE THIS AFTERNOON WITH
HIGHS ABOVE NORMAL OVER MOST AREAS.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 416 AM EST MON DEC 7 2015
FOCUS IN LONG TERM CONTINUES TO BE ON MID LEVEL AMPLIFICATION
THROUGH THE PERIOD AND POSSIBLE RECORD SETTING TEMPERATURES BY THE
WEEKEND ALONG WITH MODERATE TO HEAVY RAINFALL POTENTIAL.
INITIALLY...WILL BE CAUTIOUSLY OPTIMISTIC THAT WIDESPREAD DENSE FOG
WILL NOT BE AN ISSUE TO START THE PERIOD TUESDAY MORNING. SFC
GRADIENT SHOULD BE INCREASING AS HIGH PRESSURE SLIDES EAST AND NEXT
SHORT WAVE AND SFC TROUGH APPROACH FROM WEST. SOUNDINGS AND CROSS
SECTIONS DO SHOW RESIDUAL MOISTURE SO MOSTLY CLOUDY TO START THE
DAY. MIXING MAY ALLOW FOR PARTLY CLOUDY SKIES MID DAY BUT WILL
QUICKLY GO BACK TO CLOUDY AS NEXT PACIFIC SHORT WAVE MOVES IN
TUESDAY NIGHT INTO WEDNESDAY. IT STILL APPEARS ENOUGH MOISTURE AND
WEAK LIFT TO SUPPORT LOW PCPN CHANCES FOR LIGHT SHOWERS WITH DECENT
DPVA AND MODEST MOISTURE PROFILES. HIGHS WILL BE IN THE 40S DURING
THIS PERIOD WITH LOWS IN THE UPPER 30S TO EVEN LOWER 40S WITH
CLOUDS.
THIS MID WEEK SYSTEM MARKS THE NOSE OF MUCH STRONGER JET ENERGY
WHICH ORIGINATED OVER EAST ASIA LAST WEEK AND HAS FINALLY MADE ITS
WAY OVER THE WESTERN CONUS. AN IMPRESSIVE 120-140 KT JET CORE
STRETCHES OVER THE ENTIRE PACIFIC WITH 160+ KT EMBEDDED STREAKS PER
MODELS. THIS ENERGY WILL CONTINUOUSLY DRIVE INLAND OVER WESTERN
CONUS THIS WEEK...PROGRESSIVELY CARVING OUT A DEEP TROUGH IN THE
SOUTHWEST. AS A RESULT...HEIGHTS WILL BUILD OVER THE MIDWEST AND
STRENGTHENING LOW LEVEL JET WILL PUMP VERY WARM AND MOIST AIR INTO
THE REGION BY LATE WEEK AND SETTING THE STAGE FOR POSSIBLE HEAVY
RAINFALL. STILL A LOT OF UNCERTAINTY AND RUN TO RUN INCONSISTENCIES
BETWEEN MODELS FOR MUCH ADDED FORECAST DETAILS.
HOWEVER...PATTERN IS SUPPORTED BY MOST MODELS AND FITS THE LARGER EL
NINO PATTERN.
TEMPERATURES WILL REMAIN MILD THIS WEEK AND LOOK VERY WARM BY THE
WEEKEND WITH GUIDANCE ALREADY POINTING TO POTENTIAL RECORD HIGHS IN
THE 60S TO EVEN 70 IN OUR FAR SOUTH. CLOUDS AND RAIN WILL HAVE A LOT
TO DO WITH HOW WARM WE ACTUALLY GET BUT POTENTIAL IS CERTAINLY
THERE. ECMWF AND GFS ALSO DIFFER ON HOW ENERGY WILL EJECT OUT OF
SOUTHWEST AND IMPACT US LOCALLY. GFS CONTINUES TO SHOW A COUPLED JET
STRUCTURE BUT ECMWF BRINGS JET ENERGY OUT IN SEPARATED WAVES.
REGARDLESS...POPS IN HIGH CHANCE TO LIKELY CATEGORY WARRANTED. HIGH
PRECIPITABLE WATER VALUES OF 1-1.25 INCHES ALSO SHOWN BY GFS AND
WILL BE NEAR RECORD TERRITORY FOR MID DECEMBER SO THREAT FOR HEAVY
RAIN IS A POSSIBILITY. DETAILS AND TIMING WILL NEED TO BE SORTED OUT
WITH TIME AS MORE OF THIS JET CORE COMES ONSHORE AND GETS SAMPLED
BETTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 113 AM EST MON DEC 7 2015
HAVE MADE SIGNIFICANT CHANGES TO THE ONGOING TAFS WITH THE 06Z
ISSUANCE. SOME LIMITED CLEARING WITH VERY WEEK FLOW AT THE SURFACE
AND LOW LAYERS HAS ALREADY ALLOWED PATCHY DENSE FOG TO DEVELOP
OVER NORTHERN INDIANA BEFORE 06Z. THE FOG WAS MUCH MORE
WIDESPREAD OVER LOWER MICHIGAN AND TO A LESSER EXTENT NORTHEAST
ILLINOIS. MOST TEMP/DEW POINT SPREADS WERE 3 DEGREES OR LESS.
GIVEN THE LATEST OBSERVATIONS AND TRENDS AND GIVEN THE LATEST HIGH
RESOLUTION NCEP/WPC ESPECIALLY THE HRRR AND ARW...EXPECT THE FOG
TO DEVELOP AND BECOME DENSE BEFORE 12Z. GIVEN THE WEAK
FLOW...LIMITED INSOLATION THE FOG WILL BE VERY SLOW TO
LIFT...WITH LINGERING STRATUS LIKELY THIS AFTERNOON.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...DENSE FOG ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
INZ003>009-012>016-020.
MI...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR MIZ077>081.
OH...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR OHZ001-002.
LM...NONE.
&&
$$
SYNOPSIS...AGD/SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER
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 INDIANAPOLIS IN
321 AM EST MON DEC 7 2015
.UPDATE...
THE LONG TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 211 PM EST SUN DEC 6 2015
A SERIES OF UPPER WAVES WILL BRING SMALL RAIN CHANCES TO CENTRAL
INDIANA TONIGHT AND AGAIN WEDNESDAY. THEN...A DEEP UPPER TROUGH WILL
SET UP OVER THE SOUTHWESTERN STATES. DISTURBANCES WILL EJECT
NORTHEASTWARD AROUND THE BASE OF THE UPPER TROUGH AND THROUGH THE
OHIO VALLEY. ALSO...A FRONTAL SYSTEM WILL APPROACH FROM THE WEST.
THESE FEATURES WILL INTERACT WITH INCREASING AMOUNTS OF MOISTURE TO
BRING PROLONGED RAIN CHANCES TO ALL OF CENTRAL INDIANA LATE NEXT
WEEK AND NEXT WEEKEND.
TEMPERATURES WILL START OFF SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE
MID TO UPPER 40S MONDAY. IT WILL BECOME EVEN MORE MILD LATER IN THE
WEEK AND NEXT WEEKEND WITH AFTERNOON HIGHS IN THE LOWER 60S POSSIBLE
BY SATURDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 746 PM EST SUN DEC 6 2015
0030Z UPDATE...MAIN UPDATE EARLY THIS EVENING WAS TO INCREASE THE
COVERAGE FOR LIGHT RAIN SHOWERS EARLY THIS EVENING BASED ON LATEST
RADAR MOSAIC AND HRRR SOLUTION. THIS INCREASES THE POPS ACROSS
SOME OF THE NORTHERN COUNTIES THROUGH THIS EVENING BEFORE THE
BETTER LIFT AND MOISTURE MOVES SOUTH OF THE AREA. OTHER MINOR
UPDATES WERE MADE TO ACCOUNT FOR THE LATEST IN TEMP/DEW POINT/WIND
DIR/SPEED TRENDS. ZFPIND AND ASSOCIATED FORECAST PRODUCTS ALREADY.
PREVIOUS DISCUSSION FOLLOWS.
POPS WILL BE THE MAIN FOCUS TONIGHT AS AN UPPER LOW MOVES THROUGH
THE ZONAL FLOW ALOFT AND TRACKS ACROSS THE INDIANA-MICHIGAN BORDER.
WATER VAPOR LOOP WAS SHOWING THE UPPER LOW SPINNING ACROSS
SOUTHEASTERN IOWA THIS AFTERNOON. THE MODELS ARE CLOSE AND BRING THE
CENTER OF THE LOW TO NORTHEASTERN ILLINOIS BY 00Z TONIGHT AND TO
WESTERN PARTS OF LAKE ERIE 12Z MONDAY. THE 12Z GFS...NAM AND GEM HAD
ALL THE QPF NEAR AND SOUTH OF INTERSTATE 70...WHEREAS THE 00Z ECMWF
HAD IT FURTHER NORTH ACROSS MUCH OR ALL OF CENTRAL INDIANA. THIS
SEEMS TO GO ALONG THE FORMER MODELS BEING MORE COMPACT AND FURTHER
SOUTH WITH THE HIGHER 1000-500 MILLIBAR RH BULLSEYE. WILL GO WITH
THE MAJORITY AND KEEP CHANCE POPS SOUTH AND TRANSITION TO DRY ACROSS
THE NORTHERNMOST TIER OR TWO. THE RAIN SHOWERS SHOULD BE ENDING FROM
WEST TO EAST OVERNIGHT.
WITH LOW STRATOCU DECK AROUND...PREFER THE WARMER 12Z GFS AND
ENSEMBLE MOS. THE WET BULB ZERO TEMPERATURE SHOULD STAY JUST ABOVE
FREEZING...SO DO NOT THINK WE WILL SEE A MIX OR CHANGEOVER OF THE
RAIN SHOWERS TO SNOW SHOWERS. ALSO...SOME UPSTREAM LOW VISIBILITIES
WERE SEEN IN THE SURFACE OBS ACROSS MISSOURI AND IOWA EARLY THIS
AFTERNOON...SO WILL INCLUDE PATCHY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 211 PM EST SUN DEC 6 2015
MAIN CHALLENGE TO THE SHORT TERM WILL BE POPS AND CLOUD COVER AS
MODELS HAVE A PAIR OF UPPER WAVES MOVING THROUGH THE VICINITY
THROUGH WEDNESDAY. MODELS ARE HAVING DIFFERENCES WITH TIMING AND
LOCATION WITH THESE FEATURES...WHICH MANY TIMES IS THE CASE IN
DISTURBANCES MOVING THROUGH FAST ZONAL FLOW.
THE WORK WEEK SHOULD START OFF WITH LINGERING STRATUS AND PATCHY FOG
AS THE UPPER LOW MOVES TO WESTERN PARTS OF LAKE ERIE. MODEL
SOUNDINGS SUGGEST STRONG INVERSION SHOULD KEEP AT LEAST SOME
STRATOCU AROUND...AND LOCAL TRAPPING FLOW CHART SUGGESTS CLOUDS WILL
HANG AROUND UP TO 24 HOURS LONGER THAN MOS SUGGESTS. SO...WILL SHOOT
FOR MOSTLY CLOUDY TOMORROW. THIS SHOULD ALSO KEEP TEMPERATURES FROM
HITTING 50 DEGREES DESPITE NICE LOW LEVEL THERMAL SETUP.
THE 12Z GFS...CANADIAN AND NAM ARE THEN MUCH STRONGER AND FASTER AND
FURTHER NORTH BRINGING AN UPPER WAVE OVER THE GREAT LAKES MONDAY
NIGHT. THE 00Z ECMWF DOES NOT BRING THE WAVE ACROSS UNTIL TUESDAY
AND BRINGS IT ACROSS THE OHIO VALLEY. EITHER WAY...MOISTURE IS
LACKING SO...WILL NOT HAVE POPS MONDAY NIGHT OR TUESDAY.
BY TUESDAY...THE LOWER LEVELS DRY ENOUGH THAT THERE SHOULD BE SOME
SUNSHINE AROUND AFTER MORE MORNING STRATUS. LOW LEVEL THERMAL PROGS
AND SOME SUNSHINE SUGGEST TEMPERATURES SHOULD BE A FEW DEGREES
WARMER ON TUESDAY WITH MOS BLEND OF UPPER 40S TO LOWER 50S.
THE LAST WAVE OF CONCERN SHOULD MOVE THROUGH THE OHIO VALLEY AND
GREAT LAKES ON WEDNESDAY. THE 12Z NAM LOOKS TO BE THE ODD ONE OUT
BEING MUCH FURTHER NORTH. WITH INCREASING SOUTHWESTERLY FLOW OVER
THE AREA ON THE BACK SIDE OF AN EAST COAST HIGH...WILL SEE
INCREASING MOISTURE TO GO ALONG WITH DECENT FORCING. THUS...AT LEAST
CHANCE POPS FOR RAIN SHOWERS LOOK GOOD ACROSS ALL OF CENTRAL INDIANA
ON WEDNESDAY.
THE CLOUDS WILL KEEP TEMPERATURES FROM FALLING MUCH TUESDAY NIGHT
WITH LOWS IN THE UPPER 30S TO LOWER 40S. THE CLOUDS AND SHOWERS
SHOULD ALSO KEEP TEMPERATURES FROM RISING TOO MUCH WEDNESDAY WITH
HIGHS IN THE UPPER 40S AND LOWER 50S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 321 AM EST MON DEC 7 2015
WEATHER PATTERN WILL BECOME INCREASINGLY ACTIVE THROUGH THE
EXTENDED AS A DEEP MERIDIONAL UPPER TROUGH AMPLIFIES OVER THE
WESTERN U S AND PROGRESSES EAST OVER THE WEEKEND. QUASI-ZONAL FLOW
INITIALLY WILL TRANSITION TO A BROAD RIDGING BY SATURDAY OVER MUCH
OF THE EASTERN HALF OF THE COUNTRY...RESULTING IN UNSEASONABLY
MILD TEMPERATURES THROUGH MUCH OF THE PERIOD.
FIRST PART OF THE EXTENDED WILL BE GENERALLY QUIET WITH THE
POTENTIAL FOR JUST A FEW SHOWERS THURSDAY NIGHT INTO FRIDAY AS LOW
PRESSURE TRACKS THROUGH THE UPPER GREAT LAKES. BULK OF THE FORCING
ALOFT ASSOCIATED WITH THIS FEATURE WILL REMAIN DISPLACED TO THE
NORTHWEST...BUT PRESENCE OF A WEAK BOUNDARY SOUTH INTO THE
FORECAST AREA SHOULD BE ENOUGH TO GENERATE A FEW SHOWERS.
THE REMNANT BOUNDARY WILL STALL ACROSS THE OHIO VALLEY FRIDAY
BEFORE GETTING PICKED UP AND SHIFTED NORTH AS LOW PRESSURE
ORGANIZES OVER THE SOUTHERN PLAINS. STRONG SOUTHERLY FLOW ON THE
BACK SIDE OF HIGH PRESSURE OFF THE SOUTHEAST COAST WILL DRAW
PROGRESSIVELY DEEPER GULF MOISTURE INTO THE OHIO VALLEY FOR THE
WEEKEND WITH INCREASING CHANCES FOR SHOWERS.
EXTENDED MODELS HAVE LARGELY FLIPPED IN THEIR SOLUTIONS FROM RUNS
SATURDAY...WITH THE ECMWF NOW DEVELOPING A RAPIDLY DEEPENING
SURFACE LOW OVER THE REGION FOR LATE WEEKEND WHILE THE OP GFS
MAINTAINS A MORE PROGRESSIVE AND WEAKER SOLUTION. ECMWF HAS
SUPPORT FROM A NUMBER OF THE GFS ENSEMBLE MEMBERS AND THE SYSTEM
STRENGTH ALONE ARGUES FOR CONVECTION IMPACTING THE FORECAST AREA
SUNDAY/SUNDAY NIGHT. NOT READY JUST YET TO INTRODUCE ISOLATED
THUNDER BUT IF TRENDS CONTINUE IN THE DIRECTION OF THE STRONGER
SURFACE LOW...COULD CERTAINLY SEE A FEW THUNDERSTORMS ALONG THE
FRONT. POTENTIAL IS THERE FOR WINDY AND SHOWERY CONDITIONS WITH
IMPRESSIVE GULF MOISTURE PLUME ADVECTING INTO THE OHIO VALLEY
BRINGING PRECIP WATER VALUES NEAR CLIMATOLOGICAL MAX LEVELS FOR
MID DECEMBER.
HIGHS WILL REMAIN MILD THROUGH MUCH OF THE PERIOD...WARMING INTO
THE 60S FOR THE WEEKEND WITH STRONG SOUTHERLY FLOW AHEAD OF THE
COLD FRONT. DRIER AND COOLER CONDITIONS WILL RETURN FOR EARLY NEXT
WEEK AS THE STORM SYSTEM RAPIDLY MOVES AWAY TO THE NORTHEAST.
&&
.AVIATION /DISCUSSION FOR THE 070900Z TAFS/...
ISSUED AT 321 AM EST MON DEC 7 2015
LAST OF THE LIGHT RAIN SHOWERS ASSOCIATED WITH THE UPPER WAVE
SHOULD BE CLEAR OF KIND NEAR OR SHORTLY AFTER 09Z. SKIES HAVE
CLEARED RELATIVELY QUICKLY OVER THE NORTHERN WABASH VALLEY AND
ALREADY SEEING RESTRICTIONS DEVELOP AS FOG FORMS. HITTING FOG AND
LOWER CEILINGS HARDER INITIALLY AT BOTH KHUF AND KLAF OVER THE
NEXT SEVERAL HOURS AND MAY NEED TO CONSIDER AT KBMG AND KIND AS
WELL. CONFIDENCE REMAINS LOW IN THE PARTICULARS HOWEVER WITH POOR
MODEL SUPPORT.
06Z DISCUSSION FOLLOWS.
VFR INITIALLY WILL GIVE WAY TO MVFR OR WORSE RESTRICTIONS LATER
TONIGHT INTO MONDAY. VERY LOW CONFIDENCE FORECAST HOWEVER AS VARIOUS
GUIDANCE PRODUCTS DIFFER SIGNIFICANTLY IN THEIR HANDLING OF EXPECTED
CONDITIONS AND CONDITIONS UPSTREAM VARY SIGNIFICANTLY.
WILL GENERALLY TREND THINGS DOWN TO LOW END MVFR BY THE EARLY PART
OF THE OVERNIGHT AND KEEP THEM THERE THROUGH EARLY AFTERNOON MONDAY
AS GUIDANCE TYPICALLY CLEARS SKIES FAR TOO EARLY IN THESE SITUATIONS.
WINDS WILL BE 5KT OR LESS THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...SMF/MK
SHORT TERM...MK
LONG TERM....RYAN
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
137 AM EST MON DEC 7 2015
.SYNOPSIS...
ISSUED AT 113 AM EST MON DEC 7 2015
AREAS OF FOG ARE LIKELY EARLY THIS MORNING BUT THERE IS STILL
SOME UNCERTAINTY AS TO EXACT COVERAGE AND HOW DENSE IT WILL BE.
LOWS TONIGHT WILL BE AROUND 30 DEGREES. HIGHS TODAY WILL BE IN
THE LOW TO MID 40S. THE NEXT CHANCE OF RAIN WILL ARRIVE LATE
TUESDAY INTO WEDNESDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 333 PM EST SUN DEC 6 2015
FOG AND STRATUS ONCE AGAIN THE PRIMARY CONCERN OF THE SHORT TERM
PERIOD. UPPER LOW CURRENTLY APPROACHING OUR AREA AND WILL BRING
INCREASING MIDLEVEL CLOUDS THIS EVENING. A FEW LIGHT RETURNS NOTED
ON UPSTREAM RADAR BUT VERY FEW PRECIP REPORTS AT THE SURFACE. A
STRAY SPRINKLE MAY BE POSSIBLE SOUTH OF US-30 LATE THIS EVENING BUT
CHANCES FOR MEASURABLE RAIN APPEAR QUITE LOW GIVEN BEST CVA AND
MOISTURE RETURN REMAIN SOUTH OF OUR CWA. WILL MAINTAIN JUST A SILENT
10 POP. MORE PRESSING CONCERN WILL BE POTENTIAL FOR ANOTHER ROUND OF
FOG AND STRATUS IN THE WAKE OF PASSING LOW. UPSTREAM SATELLITE AND
SURFACE OBS INDICATE A FAIRLY WIDESPREAD AREA OF LOW STRATUS AND BR
ACROSS THE UPPER MIDWEST. MIDLEVEL CLOUDS EXPECTED TO EXIT BY 06-09Z
AND RADIATIONAL COOLING WILL LIKELY SUPPORT FOG SPREADING INTO OUR
AREA GIVEN LIGHT SURFACE WINDS. NAM FORECAST SOUNDINGS AND MOS
GUIDANCE ARE SUPPORTIVE AND DID GO WITH AREAS OF FOG AFTER 06Z..BUT
EXACT COVERAGE AND DENSITY REMAIN SOMEWHAT UNCERTAIN DUE TO
COMPLICATIONS ASSOCIATED WITH PASSING HIGHER-BASED CLOUDS. COULD
POTENTIALLY SEE ANOTHER ADVISORY BEING NECESSARY BUT REALLY WONT
KNOW TRUE SCOPE OF THE EVENT UNTIL LATER TONIGHT. EXPECT LOWS AROUND
30 DEGREES SO SOME FREEZING FOG POSSIBLE BUT SHOULD BE WARMER THAN
LAST NIGHT GIVEN EXPECTED CLOUD COVER AND WARMER START. HIGH
TEMPERATURES ON MONDAY CURRENTLY EXPECTED TO BE IN THE LOW TO MID
40S BUT HIGH BUST POTENTIAL EITHER WAY DEPENDING ON DEGREE OF
MORNING CLOUDS/FOG AND SUBSEQUENT SPEED OF DIURNAL MIX OUT.
&&
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 333 PM EST SUN DEC 6 2015
START OF THE PERIOD SHOULD BE DRY BUT MAY BE PLAGUED WITH YET
ANOTHER WINDOW OF STRATUS (FOG?) INTO AT LEAST TUESDAY NIGHT AS
INVERSION LOOKS TO RE-ESTABLISH. THIS DECK COULD POTENTIALLY MORE
PROBLEMATIC WITH REGARDS TO DISSIPATION AS DEPTH OF CLOUDS MAY BE
SUBSTANTIALLY MORE THAN PAST BOUT. HAVE TRENDED TOWARDS A MORE
SUBSTANTIAL INCREASE IN CLOUDS INTO TUESDAY NIGHT WITH HINTS OF AT
LEAST PARTIAL CLEARING TUESDAY AFTERNOON. GIVEN THESE
CONCERNS...LITTLE IN THE WAY OF CHANGES TO TEMPERATURES HAS TAKEN
PLACE.
MODEL CONSENSUS CONTINUES TO SOME DEGREE AS WE HEAD TOWARDS THE
WEEKEND WITH A STRONGER WAVE MOVING IN TUESDAY NIGHT INTO WEDS WITH
AT LEAST A CHANCE OF MEASURABLE RAINFALL BUT STILL HOLDING IN CHC
CATEGORY FOR NOW AS MOISTURE WILL STILL BE LIMITED AND AREA COULD BE
SPLIT TO NORTH AND SOUTH. YET ANOTHER LOW WILL COME OUT OF THE
PLAINS AND MAYBE BRING A CHANCE OF SHOWERS. WHAT WILL HAPPEN THIS
SYSTEM IS THE START OF A DRAMATIC INCREASE IN SOUTHERLY FLOW INTO
THE REGION...SETTING THE STAGE FOR POTENTIALLY MORE SUBSTANTIAL
RAINFALL AND MUCH WARMER TEMPERATURES. TROUGH WILL DIG INTO THE WEST
WITH A DEEP CLOSED LOW CUTTING OFF AND DRIFTING EAST INTO THE
WEEKEND. A STATIONARY FRONT WILL LIKELY SETUP SOMEWHERE ACROSS THE
FORECAST AREA STARTING AS EARLY AS SAT NGT IN A NE TO SW ORIENTATION
WITH THE FIRST OF WHAT SHOULD BE 2 SURGES OF GULF MOISTURE. RAIN
CHANCES WILL INCREASE DRAMATICALLY SAT NGT INTO SUNDAY WARRANTING
HIGH CHC TO LIKELY POPS WITH EMPHASIS ON WEST/NW AREAS. TEMPERATURES
WILL SHOOT WELL INTO THE 50S AND LIKELY SOME 60S BY SAT AND SUN.
THIS WILL PLACE RECORDS IN DANGER FOR THAT PERIOD.
WHILE JUST OUTSIDE THE FORECAST PERIOD IT IS WORTHY TO NOTE MAIN
WAVE OF INTEREST WILL EJECT TOWARDS THE REGION. WITH HIGHLY VARIABLE
TRACKS AND IMPLICATIONS ON THE AREA. THE GULF WILL BE WIDE OPEN WITH
PWATS INCREASING TO OVER AN INCH...SUGGESTING AN INCREASED HEAVY
RAIN THREAT WITH POSSIBLE THUNDERSTORMS TO WORRY ABOUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 113 AM EST MON DEC 7 2015
HAVE MADE SIGNIFICANT CHANGES TO THE ONGOING TAFS WITH THE 06Z
ISSUANCE. SOME LIMITED CLEARING WITH VERY WEEK FLOW AT THE SURFACE
AND LOW LAYERS HAS ALREADY ALLOWED PATCHY DENSE FOG TO DEVELOP
OVER NORTHERN INDIANA BEFORE 06Z. THE FOG WAS MUCH MORE
WIDESPREAD OVER LOWER MICHIGAN AND TO A LESSER EXTENT NORTHEAST
ILLINOIS. MOST TEMP/DEW POINT SPREADS WERE 3 DEGREES OR LESS.
GIVEN THE LATEST OBSERVATIONS AND TRENDS AND GIVEN THE LATEST HIGH
RESOLUTION NCEP/WPC ESPECIALLY THE HRRR AND ARW...EXPECT THE FOG
TO DEVELOP AND BECOME DENSE BEFORE 12Z. GIVEN THE WEAK
FLOW...LIMITED INSOLATION THE FOG WILL BE VERY SLOW TO
LIFT...WITH LINGERING STRATUS LIKELY THIS AFTERNOON.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...AGD/SKIPPER
SHORT TERM...AGD
LONG TERM...FISHER
AVIATION...SKIPPER
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 INDIANAPOLIS IN
1155 PM EST SUN DEC 6 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 211 PM EST SUN DEC 6 2015
A SERIES OF UPPER WAVES WILL BRING SMALL RAIN CHANCES TO CENTRAL
INDIANA TONIGHT AND AGAIN WEDNESDAY. THEN...A DEEP UPPER TROUGH WILL
SET UP OVER THE SOUTHWESTERN STATES. DISTURBANCES WILL EJECT
NORTHEASTWARD AROUND THE BASE OF THE UPPER TROUGH AND THROUGH THE
OHIO VALLEY. ALSO...A FRONTAL SYSTEM WILL APPROACH FROM THE WEST.
THESE FEATURES WILL INTERACT WITH INCREASING AMOUNTS OF MOISTURE TO
BRING PROLONGED RAIN CHANCES TO ALL OF CENTRAL INDIANA LATE NEXT
WEEK AND NEXT WEEKEND.
TEMPERATURES WILL START OFF SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE
MID TO UPPER 40S MONDAY. IT WILL BECOME EVEN MORE MILD LATER IN THE
WEEK AND NEXT WEEKEND WITH AFTERNOON HIGHS IN THE LOWER 60S POSSIBLE
BY SATURDAY.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 746 PM EST SUN DEC 6 2015
0030Z UPDATE...MAIN UPDATE EARLY THIS EVENING WAS TO INCREASE THE
COVERAGE FOR LIGHT RAIN SHOWERS EARLY THIS EVENING BASED ON LATEST
RADAR MOSAIC AND HRRR SOLUTION. THIS INCREASES THE POPS ACROSS
SOME OF THE NORTHERN COUNTIES THROUGH THIS EVENING BEFORE THE
BETTER LIFT AND MOISTURE MOVES SOUTH OF THE AREA. OTHER MINOR
UPDATES WERE MADE TO ACCOUNT FOR THE LATEST IN TEMP/DEW POINT/WIND
DIR/SPEED TRENDS. ZFPIND AND ASSOCIATED FORECAST PRODUCTS ALREADY.
PREVIOUS DISCUSSION FOLLOWS.
POPS WILL BE THE MAIN FOCUS TONIGHT AS AN UPPER LOW MOVES THROUGH
THE ZONAL FLOW ALOFT AND TRACKS ACROSS THE INDIANA-MICHIGAN BORDER.
WATER VAPOR LOOP WAS SHOWING THE UPPER LOW SPINNING ACROSS
SOUTHEASTERN IOWA THIS AFTERNOON. THE MODELS ARE CLOSE AND BRING THE
CENTER OF THE LOW TO NORTHEASTERN ILLINOIS BY 00Z TONIGHT AND TO
WESTERN PARTS OF LAKE ERIE 12Z MONDAY. THE 12Z GFS...NAM AND GEM HAD
ALL THE QPF NEAR AND SOUTH OF INTERSTATE 70...WHEREAS THE 00Z ECMWF
HAD IT FURTHER NORTH ACROSS MUCH OR ALL OF CENTRAL INDIANA. THIS
SEEMS TO GO ALONG THE FORMER MODELS BEING MORE COMPACT AND FURTHER
SOUTH WITH THE HIGHER 1000-500 MILLIBAR RH BULLSEYE. WILL GO WITH
THE MAJORITY AND KEEP CHANCE POPS SOUTH AND TRANSITION TO DRY ACROSS
THE NORTHERNMOST TIER OR TWO. THE RAIN SHOWERS SHOULD BE ENDING FROM
WEST TO EAST OVERNIGHT.
WITH LOW STRATOCU DECK AROUND...PREFER THE WARMER 12Z GFS AND
ENSEMBLE MOS. THE WET BULB ZERO TEMPERATURE SHOULD STAY JUST ABOVE
FREEZING...SO DO NOT THINK WE WILL SEE A MIX OR CHANGEOVER OF THE
RAIN SHOWERS TO SNOW SHOWERS. ALSO...SOME UPSTREAM LOW VISIBILITIES
WERE SEEN IN THE SURFACE OBS ACROSS MISSOURI AND IOWA EARLY THIS
AFTERNOON...SO WILL INCLUDE PATCHY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 211 PM EST SUN DEC 6 2015
MAIN CHALLENGE TO THE SHORT TERM WILL BE POPS AND CLOUD COVER AS
MODELS HAVE A PAIR OF UPPER WAVES MOVING THROUGH THE VICINITY
THROUGH WEDNESDAY. MODELS ARE HAVING DIFFERENCES WITH TIMING AND
LOCATION WITH THESE FEATURES...WHICH MANY TIMES IS THE CASE IN
DISTURBANCES MOVING THROUGH FAST ZONAL FLOW.
THE WORK WEEK SHOULD START OFF WITH LINGERING STRATUS AND PATCHY FOG
AS THE UPPER LOW MOVES TO WESTERN PARTS OF LAKE ERIE. MODEL
SOUNDINGS SUGGEST STRONG INVERSION SHOULD KEEP AT LEAST SOME
STRATOCU AROUND...AND LOCAL TRAPPING FLOW CHART SUGGESTS CLOUDS WILL
HANG AROUND UP TO 24 HOURS LONGER THAN MOS SUGGESTS. SO...WILL SHOOT
FOR MOSTLY CLOUDY TOMORROW. THIS SHOULD ALSO KEEP TEMPERATURES FROM
HITTING 50 DEGREES DESPITE NICE LOW LEVEL THERMAL SETUP.
THE 12Z GFS...CANADIAN AND NAM ARE THEN MUCH STRONGER AND FASTER AND
FURTHER NORTH BRINGING AN UPPER WAVE OVER THE GREAT LAKES MONDAY
NIGHT. THE 00Z ECMWF DOES NOT BRING THE WAVE ACROSS UNTIL TUESDAY
AND BRINGS IT ACROSS THE OHIO VALLEY. EITHER WAY...MOISTURE IS
LACKING SO...WILL NOT HAVE POPS MONDAY NIGHT OR TUESDAY.
BY TUESDAY...THE LOWER LEVELS DRY ENOUGH THAT THERE SHOULD BE SOME
SUNSHINE AROUND AFTER MORE MORNING STRATUS. LOW LEVEL THERMAL PROGS
AND SOME SUNSHINE SUGGEST TEMPERATURES SHOULD BE A FEW DEGREES
WARMER ON TUESDAY WITH MOS BLEND OF UPPER 40S TO LOWER 50S.
THE LAST WAVE OF CONCERN SHOULD MOVE THROUGH THE OHIO VALLEY AND
GREAT LAKES ON WEDNESDAY. THE 12Z NAM LOOKS TO BE THE ODD ONE OUT
BEING MUCH FURTHER NORTH. WITH INCREASING SOUTHWESTERLY FLOW OVER
THE AREA ON THE BACK SIDE OF AN EAST COAST HIGH...WILL SEE
INCREASING MOISTURE TO GO ALONG WITH DECENT FORCING. THUS...AT LEAST
CHANCE POPS FOR RAIN SHOWERS LOOK GOOD ACROSS ALL OF CENTRAL INDIANA
ON WEDNESDAY.
THE CLOUDS WILL KEEP TEMPERATURES FROM FALLING MUCH TUESDAY NIGHT
WITH LOWS IN THE UPPER 30S TO LOWER 40S. THE CLOUDS AND SHOWERS
SHOULD ALSO KEEP TEMPERATURES FROM RISING TOO MUCH WEDNESDAY WITH
HIGHS IN THE UPPER 40S AND LOWER 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 247 PM EST SUN DEC 6 2015
A QUASI-ZONAL FLOW ALOFT WILL OCCUR DURING THE FIRST HALF OF THE
LONG TERM PERIOD AND THEN BECOME MORE AMPLIFIED OVER THE WEEKEND
AS A STRONG UPPER TROUGH DIGS INTO THE CENTRAL U.S. BY LATE
SATURDAY AND THEN MOVES TO THE WESTERN GREAT LAKES AND MISSISSIPPI
VALLEY BY THE END OF DAY 7. A WEAK UPPER DISTURBANCE WILL BRING
A CHANCE OF SHOWERS AROUND THURSDAY NIGHT AND THEN THE STRONG UPPER
TROUGH WILL BRING A GOOD CHANCE OF SHOWERS OVER THE WEEKEND...
ESPECIALLY SUNDAY. THERE MAY BE ENOUGH FORCING FOR ISOLATED THUNDER
SATURDAY NIGHT INTO SUNDAY...BUT AT THE MOMENT I DECIDED TO LEAVE IT OUT.
OVERALL SUPER BLEND SEEMED TO HANDLE POPS WELL. RAISED LOW TEMPERATURES
SLIGHTLY SOME PERIODS DUE TO CLOUDS AND STRONG WARM ADVECTION.
OTHERWISE...ONLY MINOR TWEAKS MADE DURING THE REST OF THE PERIOD. MODELS
INDICATE TEMPERATURES WILL BE WELL ABOVE NORMAL DURING THE PERIOD...BUT
POSSIBLY TURNING COOLER LATE SUNDAY WITH THE COLD FRONT.
&&
.AVIATION /DISCUSSION FOR THE 07/06Z TAFS/...
ISSUED AT 1155 PM EST SUN DEC 6 2015
VFR INITIALLY WILL GIVE WAY TO MVFR OR WORSE RESTRICTIONS LATER
TONIGHT INTO MONDAY. VERY LOW CONFIDENCE FORECAST HOWEVER AS VARIOUS
GUIDANCE PRODUCTS DIFFER SIGNIFICANTLY IN THEIR HANDLING OF EXPECTED
CONDITIONS AND CONDITIONS UPSTREAM VARY SIGNIFICANTLY.
WILL GENERALLY TREND THINGS DOWN TO LOW END MVFR BY THE EARLY PART
OF THE OVERNIGHT AND KEEP THEM THERE THROUGH EARLY AFTERNOON MONDAY
AS GUIDANCE TYPICALLY CLEARS SKIES FAR TOO EARLY IN THESE SITUATIONS.
WINDS WILL BE 5KT OR LESS THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...SMF/MK
SHORT TERM...MK
LONG TERM...JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
353 AM EST MON DEC 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM EST MON DEC 7 2015
00Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW A ZONAL SPLIT FLOW
OF PACIFIC AIR OVER SRN CANADA AND THE CONUS. SHRTWV RDG AXIS IS
MOVING INTO THE WRN GREAT LKS EARLY THIS MRNG...WITH WEAK SFC HI
PRES RDG STRETCHING FM NW ONTARIO ACRS WRN UPR MI TO STRONGER HI
PRES CENTERED OVER THE SRN PLAINS. ALTHOUGH THE AIRMASS OVHD IS
DRY...WITH 00Z PWAT AS LO AS ABOUT 0.20 INCH AT MPX...LINGERING LLVL
MSTR SHOWN ON LOCAL 00Z RAOBS TRAPPED UNDER LO SUBSIDENCE INVRN IS
CAUSING QUITE A BIT OF LO CLD/FOG OVER MUCH OF THE CWA IN THE
PRESENCE OF NOCTURNAL COOLING. THE FOG/STRATUS IS MOST EXTENSIVE
OVER THE INTERIOR W HALF OF THE CWA...WITH MORE HIER BASED SC
LINGERING OVER THE E...WHERE THE 00Z GRB/APX RAOBS SHOW MORE MSTR
NEAR HIER INVRN BASE. AREAS NEAR LK SUP W OF MUNISING...EXCEPT FOR
THE KEWEENAW...AND OVER THE SCENTRAL E OF IRON MTN ARE MOCLR...
PROBABLY DUE TO LIGHT DOWNSLOPE W TO SW WINDS IN THESE AREAS. THE LO
CLD AND FOG STRETCH W THRU MUCH OF MN. MORE HI CLD IN COMMA TAIL OF
NRN BRANCH SHRTWV/SFC LO TRACKING INTO MANITBOA IS STREAMING E INTO
MN AS WELL...BUT VERY DRY AIRMASS SHOWN ON THE ABERDEEN SDAKOTA AND
BISMARCK RAOBS IS PREVENTING ANY PCPN OR EVEN LOWER CLDS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON FOG/LO CLD
TRENDS.
TODAY...AS SFC HI PRES RDG SHIFTS TO THE E AND LO PRES MOVES INTO NW
ONTARIO...EXPECT A STEADY S WIND TO DVLP OVER UPR MI. NAM H95 RH...
WHICH HAS A GOOD HANDLE ON THE AREA OF LO CLDS RIGHT NOW...HINTS THE
AREA OF LO CLDS WL EXPAND TO ALL BUT THE NW CWA...WHERE THE S WIND
DOWNSLOPES. WHILE DAYTIME HEATING WL LIKELY LIMIT FOG COVERAGE...LO
SUN ANGLE WL PROBABLY NOT BE SUFFICIENT TO MIX OUT THE LO CLD. SO
TENDED TOWARD MORE CLD COVER EXCEPT IN THOSE DOWNSLOPE AREAS NEAR LK
SUP FM MUNISING TO BARAGA/THE KEWEENAW...ONTONAGON AND IRONWOOD.
LOWERED FCST MAX TEMPS A COUPLE DEGREES WHERE THE LO CLD IS EXPECTED
TO BE MOST EXTENSIVE. EXPECT THE WARMEST TEMPS INTO THE 40S IN THE
DOWNSLOPE AREAS NEAR LK SUP.
TNGT...AXIS OF DEEP LYR QVECTOR CNVGC IN COMMA TAIL OF SHRTWV MOVING
TO THE ENE TOWARD HUDSON BAY IS FCST TO SHIFT W-E ACRS THE CWA.
ALTHOUGH THIS FORCING WL NOT BE SUFFICIENT TO SATURATE THE VERY DRY
MID LVLS...LIFTING OF THE SUBSIDENCE INVRN WL ALLOW FOR A GREATER
DEPTH OF LLVL MSTR. MANY OF THE HIER RES MODELS GENERATE SOME LGT
PCPN...ESPECIALLY IN AREAS DOWNWIND OF LK MI IN THE EXPECTED LLVL
SSW FLOW. WL RETAIN SOME LO CHC POPS FOR DRIZZLE AND ADD SOME FOG IN
THE FCST FOR THIS AREA. THE SOMEWHAT HIER INVRN BASE WL ALSO ALLOW
FOR MORE LO CLDS TO EXPAND EVEN INTO THE DOWNSLOPE AREAS NEAR LK
SUP. TEMPS WL RUN WELL ABOVE NORMAL...MAINLY IN THE 30S...WARMEST
DOWNWIND OF LK MI.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 310 AM EST MON DEC 7 2015
LONG TERM WILL SEE SEVERAL SHORTWAVES MAKING FOR A BUSIER
PATTERN...BUT AT THIS TIME PRECIP AMOUNTS LOOK TO BE MOSTLY
INSIGNIFICANT. MAY SEE SOME MORE SIGNIFICANT PRECIP NEXT
WEEKEND...BUT PREDICTABILITY IS QUITE LOW.
MAY SEE SOME LIGHT PRECIP OVER THE E ON TUE...MAINLY TUE
MORNING...AS A SHORTWAVE PASSES THROUGH. MODELS SHOW
ANOTHER...STRONGER...SHORTWAVE MOVING THROUGH THE REGION BETWEEN TUE
EVENING AND WED AFTERNOON. MODELS CONTINUE TO DISAGREE ON STRENGTH
OF THE SHORTWAVE...SO TIMING/COVERAGE/AMOUNTS OF PRECIP ARE
UNCERTAIN. COULD SEE SOME GREATER PRECIP AMOUNTS (GFS AND NAM
SHOWING UPWARDS OF ONLY 0.2 INCHES)...BUT MOST OF THAT SHOULD FALL
AS RAIN. COULD SEE SOME VERY MINOR MEASURABLE SNOW...BUT
INSIGNIFICANT REALLY.
PRECIP ASSOCIATED WITH NEXT SHORTWAVE LOOKS TO MOVE IN LATE WED
NIGHT. MAY SEE PRECIP CONFINED TO THE NRN CWA AHEAD OF THE SYSTEM
THROUGH THU MORNING...THE WILL BE MORE LIKELY TO COVER MOST OF THE
AREA THU AFTERNOON INTO THU NIGHT. COULD SEE SOME MINOR MEASURABLE
SNOW OVER THE W THU EVENING INTO THU NIGHT...BUT DETAILS ARE STILL
TOO SKETCHY TO SAY WITH CONFIDENCE.
STILL SEE SOME POTENTIAL FOR A STRONGER SYSTEM TO MOVE THROUGH LATER
NEXT WEEKEND...BUT THAT IS HIGHLY UNCERTAIN. MODELS DO CONTINUE TO
SHOW COLDER AIR CAPABLE OF SUPPORTING LES AS THE WEEKEND GOES
ON...BUT EXACT EXTENT AND EVEN WIND DIRECTION IS UNCERTAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1224 AM EST MON DEC 7 2015
LOW CLOUDS AND FOG HAVE MOVED INTO KSAW AS EXPECTED...BUT BOTH
LOWER THAN ORIGINALLY EXPECTED WITH LIFR/VLIFR CONDITIONS THERE.
MEANWHILE KCMX HAS CLEARED OUT. SOME MIST DEVELOPING AT BOTH KCMX AND
KIWD...BUT AT THIS TIME DO NOT EXPECT ANY SGNFT IMPACTS AT EITHER
SITE...BUT KIWD NEEDS TO BE MONITORED CLOSELY DUE TO PROXIMITY OF
ST/FG JUST TO THE SOUTHEAST. VSBYS HAVE DROPPED TO IFR/VIFR OVER
PORTIONS OF THE CENTRAL U.P. AND THIS HAS IMPACTED KSAW THIS MORNING.
EXPECT THESE VSBYS TO IMPROVE TO MVFR SHORTLY AFTER SUNRISE WITH THE
FOG DISSIPATING SHORTLY THEREAFTER. VFR CONDITIONS SHOULD THEN
PREVAIL OVER THE AREA UNTIL LOW CLOUDS MAKE A RETURN TO KSAW LATE IN
THE FORECAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 310 AM EST MON DEC 7 2015
THE PRESSURE GRADIENT WILL INCREASE THIS AFTERNOON INTO TONIGHT AS A
LOW PRESSURE SYSTEM MOVES INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25-30 KNOT WIND GUSTS TONIGHT INTO TUE MORNING. ANOTHER
PERIOD OF SOUTHERLY 25 KNOT WINDS IS EXPECTED THU INTO THU NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...RJT
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
313 AM EST MON DEC 7 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 405 PM EST SUN DEC 6 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A SPLIT FLOW PATTERN ACROSS
NORTH AMERICA WITH A SRN STREAM MID LEVEL LOW OVER ILLINOIS AND THE
ACTIVE PORTION OF THE NRN STREAM BRANCH WELL TO THE NORTH THROUGH
NRN ONTARIO AND JAMES BAY. THE NRN ONTARIO SHRTWV HAS DRAGGED A WEAK
COLD FRONT THROUGH THE NRN LAKES WITH DRIER AIR AND ACYC COMBINED
WITH DAYTIME MIXING HELPING TO SCOUR OUT THE LOW CLOUDS OVER MUCH OF
UPPER MICHIGAN...EXCEPT OVER THE KEWEENAW AND THE EAST.
TONIGHT...THE MODELS SHOW MID LEVEL AND SFC RIDGING BUILDING INTO
THE WRN LAKES TONIGHT WITH PWAT VALUES DROPPING AOB 0.25 INCH OVER
MUCH OF UPPER MICHIGAN. ALTHOUGH THERE MAY BE A PERIOD OF CLEARING
INTO THIS EVENING...EXPECT THAT WITH FAVORABLE RADIATIONAL COOLING
CONDITIONS AND LINGERING LOW LEVEL MOISTURE WITH DEWPOINTS FROM LATE
AFTERNOON IN THE LOWER 30S...AREAS OF FOG WILL DEVELOP. ISOLD DENSE
FOG WILL ALSO BE POSSIBLE...BUT CONFIDENCE IN TIMING/LOCATIONS IS
NOT AS HIGH. DEVELOPING DOWNSLOPE SSW LOW LEVEL FLOW OVER THE WEST
WILL LIMIT FOG POTENTIAL IN THE WEST HALF NEAR LAKE SUPERIOR.
MONDAY...HIGHER RES MODELS 925MB RH FCST SUGGESTS THAT ADDITIONAL SW
FLOW DRY ADVECTION ALONG WITH LIMITED WINTER TIME DAYTIME WILL BE
ENOUGH TO AGAIN SCOUR OUT ANY LEFTOVER CLOUDS/FOG DURING THE MORNING.
THIS SHOULD ALLOW TEMPS TO CLIMB INTO THE LOW TO MID 40S WITH UPPER
40S WITH DOWNSLOPE FLOW NEAR LAKE SUPERIOR.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 310 AM EST MON DEC 7 2015
LONG TERM WILL SEE SEVERAL SHORTWAVES MAKING FOR A BUSIER
PATTERN...BUT AT THIS TIME PRECIP AMOUNTS LOOK TO BE MOSTLY
INSIGNIFICANT. MAY SEE SOME MORE SIGNIFICANT PRECIP NEXT
WEEKEND...BUT PREDICTABILITY IS QUITE LOW.
MAY SEE SOME LIGHT PRECIP OVER THE E ON TUE...MAINLY TUE
MORNING...AS A SHORTWAVE PASSES THROUGH. MODELS SHOW
ANOTHER...STRONGER...SHORTWAVE MOVING THROUGH THE REGION BETWEEN TUE
EVENING AND WED AFTERNOON. MODELS CONTINUE TO DISAGREE ON STRENGTH
OF THE SHORTWAVE...SO TIMING/COVERAGE/AMOUNTS OF PRECIP ARE
UNCERTAIN. COULD SEE SOME GREATER PRECIP AMOUNTS (GFS AND NAM
SHOWING UPWARDS OF ONLY 0.2 INCHES)...BUT MOST OF THAT SHOULD FALL
AS RAIN. COULD SEE SOME VERY MINOR MEASURABLE SNOW...BUT
INSIGNIFICANT REALLY.
PRECIP ASSOCIATED WITH NEXT SHORTWAVE LOOKS TO MOVE IN LATE WED
NIGHT. MAY SEE PRECIP CONFINED TO THE NRN CWA AHEAD OF THE SYSTEM
THROUGH THU MORNING...THE WILL BE MORE LIKELY TO COVER MOST OF THE
AREA THU AFTERNOON INTO THU NIGHT. COULD SEE SOME MINOR MEASURABLE
SNOW OVER THE W THU EVENING INTO THU NIGHT...BUT DETAILS ARE STILL
TOO SKETCHY TO SAY WITH CONFIDENCE.
STILL SEE SOME POTENTIAL FOR A STRONGER SYSTEM TO MOVE THROUGH LATER
NEXT WEEKEND...BUT THAT IS HIGHLY UNCERTAIN. MODELS DO CONTINUE TO
SHOW COLDER AIR CAPABLE OF SUPPORTING LES AS THE WEEKEND GOES
ON...BUT EXACT EXTENT AND EVEN WIND DIRECTION IS UNCERTAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1224 AM EST MON DEC 7 2015
LOW CLOUDS AND FOG HAVE MOVED INTO KSAW AS EXPECTED...BUT BOTH
LOWER THAN ORIGINALLY EXPECTED WITH LIFR/VLIFR CONDITIONS THERE.
MEANWHILE KCMX HAS CLEARED OUT. SOME MIST DEVELOPING AT BOTH KCMX AND
KIWD...BUT AT THIS TIME DO NOT EXPECT ANY SGNFT IMPACTS AT EITHER
SITE...BUT KIWD NEEDS TO BE MONITORED CLOSELY DUE TO PROXIMITY OF
ST/FG JUST TO THE SOUTHEAST. VSBYS HAVE DROPPED TO IFR/VIFR OVER
PORTIONS OF THE CENTRAL U.P. AND THIS HAS IMPACTED KSAW THIS MORNING.
EXPECT THESE VSBYS TO IMPROVE TO MVFR SHORTLY AFTER SUNRISE WITH THE
FOG DISSIPATING SHORTLY THEREAFTER. VFR CONDITIONS SHOULD THEN
PREVAIL OVER THE AREA UNTIL LOW CLOUDS MAKE A RETURN TO KSAW LATE IN
THE FORECAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 310 AM EST MON DEC 7 2015
THE PRESSURE GRADIENT WILL INCREASE THIS AFTERNOON INTO TONIGHT AS A
LOW PRESSURE SYSTEM MOVES INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25-30 KNOT WIND GUSTS TONIGHT INTO TUE MORNING. ANOTHER
PERIOD OF SOUTHERLY 25 KNOT WINDS IS EXPECTED THU INTO THU NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...RJT
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1225 AM EST MON DEC 7 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 405 PM EST SUN DEC 6 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A SPLIT FLOW PATTERN ACROSS
NORTH AMERICA WITH A SRN STREAM MID LEVEL LOW OVER ILLINOIS AND THE
ACTIVE PORTION OF THE NRN STREAM BRANCH WELL TO THE NORTH THROUGH
NRN ONTARIO AND JAMES BAY. THE NRN ONTARIO SHRTWV HAS DRAGGED A WEAK
COLD FRONT THROUGH THE NRN LAKES WITH DRIER AIR AND ACYC COMBINED
WITH DAYTIME MIXING HELPING TO SCOUR OUT THE LOW CLOUDS OVER MUCH OF
UPPER MICHIGAN...EXCEPT OVER THE KEWEENAW AND THE EAST.
TONIGHT...THE MODELS SHOW MID LEVEL AND SFC RIDGING BUILDING INTO
THE WRN LAKES TONIGHT WITH PWAT VALUES DROPPING AOB 0.25 INCH OVER
MUCH OF UPPER MICHIGAN. ALTHOUGH THERE MAY BE A PERIOD OF CLEARING
INTO THIS EVENING...EXPECT THAT WITH FAVORABLE RADIATIONAL COOLING
CONDITIONS AND LINGERING LOW LEVEL MOISTURE WITH DEWPOINTS FROM LATE
AFTERNOON IN THE LOWER 30S...AREAS OF FOG WILL DEVELOP. ISOLD DENSE
FOG WILL ALSO BE POSSIBLE...BUT CONFIDENCE IN TIMING/LOCATIONS IS
NOT AS HIGH. DEVELOPING DOWNSLOPE SSW LOW LEVEL FLOW OVER THE WEST
WILL LIMIT FOG POTENTIAL IN THE WEST HALF NEAR LAKE SUPERIOR.
MONDAY...HIGHER RES MODELS 925MB RH FCST SUGGESTS THAT ADDITIONAL SW
FLOW DRY ADVECTION ALONG WITH LIMITED WINTER TIME DAYTIME WILL BE
ENOUGH TO AGAIN SCOUR OUT ANY LEFTOVER CLOUDS/FOG DURING THE MORNING.
THIS SHOULD ALLOW TEMPS TO CLIMB INTO THE LOW TO MID 40S WITH UPPER
40S WITH DOWNSLOPE FLOW NEAR LAKE SUPERIOR.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM EST SUN DEC 6 2015
MUCH OF THIS PERIOD WILL BE MARKED BY 500MB WAVES IN WHAT GENERALLY
LOOKS LIKE ZONAL FLOW...WITH A SERIES OF WEAK SFC LOWS SPINNING
ACROSS CANADA IMPACTING THE UPPER GREAT LAKES THROUGH THE WORK WEEK.
OVERALL LIGHT PRECIP IS ANTICIPATED.
BY 00Z TUESDAY THE INITIAL 500MB TROUGH WILL BE WELL TO OUR E /OVER
PA/...WITH AN EXITING RIDGE OVER THE UPPER GREAT LAKES AHEAD OF THE
NEXT TROUGH SET UP FROM N MANITOBA THROUGH MN/IA. A BROAD SFC LOW
WAS OVER MUCH OF W AND CENTRAL CANADA. THE E LOBE OF THIS TROUGH
WILL BE ACROSS N ONTARIO...DROPPING A COLD FRONT ACROSS OUR AREA.
THE RESULT WILL BE INCREASED MID AND HIGH CLOUDS THAT WILL CONTINUE
INTO EARLY WEDNESDAY MORNING. WHILE FCST MODELS DO INDICATE SOME
CHANCE OF PRECIPITATION...MUCH OF THAT IS LIGHT AND OVER THE E HALF
OF THE CWA. THERE WILL BE AS AN ADDITIONAL TROUGH IN THE BROAD
CANADIAN LOW SWINGS ACROSS S MANITOBA/ND TUESDAY AFTERNOON AND OVER
THE UPPER GREAT LAKES WEDNESDAY MORNING.
ZONAL FLOW/SLIGHT RIDGING BRIEFLY TAKES HOLD LATE WEDNESDAY
AFTERNOON INTO WEDNESDAY EVENING...WHILE THE NEXT 500MB TROUGH SETS
UP OVER S SASKATCHEWAN/MT. THE LAST AND STRONGEST PART OF THE
CANADIAN LOW WILL BE OVER S CENTRAL CANADA AT 06Z THURSDAY. LOOK FOR
THIS LOW TO SHIFT ACROSS N MN THURSDAY MORNING AND THEN ACROSS N
LAKE SUPERIOR/ONTARIO THURSDAY EVENING. THE LOW WILL CONTINUE TO
TRACK TO AROUND JAMES BAY BY 18Z FRIDAY. THERE ARE SOME
DISCREPANCIES...AS THE GFS AND CANADIAN RUNS EJECT THE LOW TO THE NE
MUCH QUICKER THAN THE 00Z RUN OF THE ECMWF FRIDAY NIGHT. THE 12Z
ECMWF SPED THE SYSTEM UP A BIT...BUT IT/S STILL ON THE SLOW SIDE.
JUST HOW MUCH MOISTURE WILL BE ABLE TO SURGE N INTO OUR AREA IS ALSO
IN QUESTION. THE SLOWER ECMWF GIVES MORE TIME FOR MOISTURE TO POOL
TO OUR S...AND MOVE OVERHEAD THURSDAY NIGHT. THE RESULT IS LOWER
THAN AVERAGE CONFIDENCE IN THE ONGOING FCST FROM FRIDAY ON.
A MORE ROBUST SYSTEM SHOULD SET UP OVER THE W HALF OF THE NATION
SATURDAY...IN THE FORM OF A SIGNIFICANT 500MB TROUGH. EXACTLY WHERE
THE SFC LOW SETS UP IS STILL A CONCERN AS THE 00Z RUN OF THE ECMWF
TIES IT TO THE SLOWER LOW IMPACTING OUR WEATHER THURSDAY INTO EARLY
FRIDAY. THE 12Z ECMWF SETS UP THE SECONDARY LOW WELL TO THE S. THE
GFS ON THE OTHER HAND HAS A STRONGER SFC LOW OVER THE CENTRAL PLAINS
AT 00Z SATURDAY MOVING ACROSS OUR AREA SATURDAY NIGHT. THE RESULT IS
MUCH MORE QPF OFF THE GFS...WHILE THE ECMWF PUSHES THE SWATH OF
HIGHEST PRECIP OVER LOWER MI SATURDAY NIGHT. EITHER WAY...COLD AIR
LOOKS POISED TO SLIDE IN FOR THE END OF THE WEEKEND WITH 850MB TEMPS
OF -5 TO -12C BY 00Z MONDAY ON W TO NNW WINDS. RIGHT NOW IT LOOKS
LIKE WE WILL AT LEAST TEMPORARILY BREAK OUR TREND OF ABOVE NORMAL
TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1224 AM EST MON DEC 7 2015
LOW CLOUDS AND FOG HAVE MOVED INTO KSAW AS EXPECTED...BUT BOTH
LOWER THAN ORIGINALLY EXPECTED WITH LIFR/VLIFR CONDITIONS THERE.
MEANWHILE KCMX HAS CLEARED OUT. SOME MIST DEVELOPING AT BOTH KCMX AND
KIWD...BUT AT THIS TIME DO NOT EXPECT ANY SGNFT IMPACTS AT EITHER
SITE...BUT KIWD NEEDS TO BE MONITORED CLOSELY DUE TO PROXIMITY OF
ST/FG JUST TO THE SOUTHEAST. VSBYS HAVE DROPPED TO IFR/VIFR OVER
PORTIONS OF THE CENTRAL U.P. AND THIS HAS IMPACTED KSAW THIS MORNING.
EXPECT THESE VSBYS TO IMPROVE TO MVFR SHORTLY AFTER SUNRISE WITH THE
FOG DISSIPATING SHORTLY THEREAFTER. VFR CONDITIONS SHOULD THEN
PREVAIL OVER THE AREA UNTIL LOW CLOUDS MAKE A RETURN TO KSAW LATE IN
THE FORECAST.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 405 PM EST SUN DEC 6 2015
THE PRES GRADIENT WILL INCREASE MON NIGHT WITH THE RIDGE SLIDING TO
THE EAST AND LOW PRES MOVING INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25 KNOT WINDS. ANOTHER PERIOD OF SRLY 25 KNOT WINDS IS
EXPECTED THU AHEAD OF LOW PRES MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...RJT
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1153 PM EST SUN DEC 6 2015
.AVIATION...
EXTENSIVE REGION OF LOW STRATUS AND FOG NOW ENCOMPASSING THE ENTIRE
SOUTHEAST MICHIGAN AIRSPACE. LATEST TRENDS CONTINUE TO SUPPORT
SEEING WIDESPREAD LIFR CONDITIONS THROUGH THE DURATION OF THE EARLY
MORNING PERIOD. ADDITIONAL MOISTURE TIED TO AN INBOUND TROUGH NOW
SHIFTING ACROSS LAKE MICHIGAN WILL ARRIVE BY MID-LATE MORNING. THIS
MOISTURE WILL REINFORCE THE EXISTING LOW STRATUS FOR MONDAY...BUT
FAVOR SOME IMPROVEMENT IN VSBY AS FLOW TURNS TO NORTHWEST.
FOR DTW...LIFR STRATUS/FOG NOW IN PLACE WILL HOLD FIRM THROUGH THE
MID MORNING PERIOD. THE EMERGENCE OF A LIGHT NORTHWEST FLOW WILL
FAVOR SOME IMPROVEMENT IN CONDITIONS AFTER 14Z. IFR LEVEL
RESTRICTIONS APPEAR LIKELY WELL INTO MONDAY UNDER CONTINUED LOW
STRATUS.
//DTW THRESHOLD PROBABILITIES...
* HIGH IN VSBY/CIGS BELOW 1/2SM AND/OR 200 FT TONIGHT.
* HIGH IN CIGS BELOW 5000 FT TONIGHT AND MONDAY.
&&
.PREV DISCUSSION...ISSUED 804 PM EST SUN DEC 6 2015
UPDATE...
ANOTHER CHALLENGING NIGHT FOR DELINEATING BOTH THE SCOPE AND
LOCATION OF STRATUS VERSUS DENSE FOG. A RATHER AGGRESSIVE
RESPONSE ALREADY UNDERWAY AGAIN TONIGHT AS THE NEAR SURFACE
ENVIRONMENT QUICKLY SATURATES. 23Z HRRR VISIBILITY OUTPUT ON
TARGET WITH CURRENT CONDITIONS...AND POINTS TOWARD A SIGNIFICANT
EXPANSION OF FOG NORTH OF I-69 THROUGH 06Z. ALREADY SIGNS OF THIS
FROM THE THUMB BACK INTO SAGINAW. ANOTHER REGION OF LOWER
VISIBILITY NOTED CENTERED BETWEEN THE I-96 CORRIDOR AND THE OHIO
BORDER. WHILE VISIBILITY HAS TANKED ACROSS PORTIONS OF THIS
CORRIDOR...NOW NOTING A SUBTLE BUT PERHAPS IMPORTANT SHIFT IN WIND
TO LIGHT NORTHWESTERLY. THE ADDED SLIGHT DOWNSLOPE OFF THE GLACIAL
RIDGE MAY VERY WELL LEAVE THIS DENSE FOG AS A TEMPORARY/MORE
LOCALIZED ISSUE...WITH A TREND TOWARD MORE OF A LOW STRATUS ISSUE.
WILL CLOSELY MONITOR VISIBILITY TRENDS MOVING FORWARD TO
DETERMINE THE NEED FOR AN ADVISORY ACROSS THIS CORRIDOR. GREATER
CONCERN CURRENTLY ACROSS THE THUMB AND TRI-CITIES...GIVEN
SUPPORTIVE MODEL AND SATELLITE EVIDENCE TO ADD CONFIDENCE FOR A
WIDESSPREAD DENSE FOG EVENT OVERNIGHT. WILL GO AHEAD WITH AN
ADVISORY FOR THIS CORRIDOR...WITH ROOM TO EXPAND SHOULD CONDITIONS
WARRANT FOR POINTS TO THE SOUTH.
PREV DISCUSSION...ISSUED 306 PM EST SUN DEC 6 2015
DISCUSSION...
NEARLY A CARBON COPY RESULT OF SATURDAY ACROSS SOUTHEAST LOWER
MICHIGAN - WITH A STUBBORN STRATUS DECK BANKED UP AGAINST THE
GLACIAL RIDGE BENEATH A VERY STRONG NEAR SURFACE THERMAL INVERSION.
AS A RESULT...THESE CLOUDS HAVE KEPT TEMPS DOWN SIGNIFICANTLY ACROSS
NORTHERN AND WESTERN SECTIONS OF THE METRO REGION. AN ADDITIONAL
MORE EXPANSIVE AREA OF STRATUS OVER THE CENTRAL LOWER PENINSULA HAS
BEEN AFFECTING THE MIDLAND REGION. ELSEWHERE...AMPLE SUN HAS
PROPELLED TEMPERATURES WELL INTO THE 40S.
A WELL DEFINED MID-TROPOSPHERIC WAVE IS CURRENTLY CYCLING ACROSS
CENTRAL ILLINOIS AND WILL PASS TO THE SOUTH OF LOWER MICHIGAN
TONIGHT. AN INVERTED SURFACE TROUGH EXTENDING NORTHWARD ACROSS
WISCONSIN...IN CONJUNCTION WITH A NARROW ELEVATED PV FILAMENT
ATTACHING THE WAVE TO THE PARENT RESERVOIR OVER THE HUDSON BAY
REGION...WILL SLIDE THROUGH THE REGION TONIGHT. THIS WILL SERVE TO
TURN THE LIGHT FLOW TO MORE WESTERLY AND ALLOW FOR ADDITIONAL LOW-
LEVEL MOISTURE ADVECTION BENEATH THE PERSISTENT INVERSION LAYER.
SPECIFICALLY...A SUBSTANTIAL STRATUS PRESENCE IS NOTED UPSTREAM IN
THE WAKE OF THE SURFACE TROUGH.
WITH THE LOSS OF INSOLATION EARLY THIS EVENING...EXPECT THE CURRENT
LOW CLOUD SHIELDS OVER AREA TO START TO EXPAND ONCE AGAIN. FOG
DEVELOPMENT IS ALSO VERY LIKELY AS RADIATIONAL COOLING SHOULD BE
MORE EFFICIENT TONIGHT DUE TO A LESSER DEGREE OF ELEVATED MOISTURE
INTERCEPTING THE OUTGOING OPTICAL PATH. THE HRRR...RAP...AND TO A
LESSER EXTENT NAM GUIDANCE ALL OFFER SOME DEPICTION OF BOTH AN
EXPANDING CLOUD/FOG SCENARIO IN COMBINATION WITH THE UPSTREAM NEAR
SURFACE MOISTURE ADVECTING INTO THE REGION OVERNIGHT.
UNFORTUNATELY...THE VERY LOW CLOUDS WILL LIKELY PERSIST EVERYWHERE
ON MONDAY...WHICH WILL GREATLY REDUCE MAX TEMPERATURE POTENTIAL. THE
NAM AND REGIONAL GEM ARE OFFERING A VERY GLOOMY PICTURE RIGHT ON
INTO TUESDAY. GIVEN THE INABILITY TO ERASE THE OMNIPRESENT
INVERSION...A MORE PESSIMISTIC DEPICTION IS THE MOST LIKELY OUTCOME.
THEREFORE...HAVE LOWERED HIGH TEMPERATURES ON MONDAY AND TUESDAY
APPRECIABLY - CERTAINLY MUCH MORE THAN ANY GUIDANCE OFFERED BY THE
GFS FAMILY...WHICH HAS NOT OFFERED ANY SKILL THUS FAR.
THE NEXT CHANCE FOR MEASURABLE PRECIPITATION WILL COME LATER IN THE
DAY ON TUESDAY AS SOME SEMBLANCE OF MID-LEVEL THETA-E ADVECTION
COMMENCES WITH A WEAK UPPER-LEVEL RIPPLE. THIS IS ESPECIALLY TRUE
ACROSS THE SAGINAW VALLEY AND THUMB REGIONS. THE NEXT WAVE OF DEEPER
THETA-E ADVECTION ARRIVES EARLY WEDNESDAY WITH A MUCH BETTER
DEFINED PACIFIC ORIGIN SHORTWAVE. THE MOISTURE QUALITY IS STILL
RATHER LOW - GIVEN ANY RETURN FLOW OFF THE GULF OF MEXICO IS
INACCESSIBLE.
WEAK SURFACE RIDGING WILL KEEP US DRY FOR WEDNESDAY NIGHT AND
MOST OF THURSDAY. A STRONGER LOW PRESSURE SYSTEM IS FORECASTED TO
TRACK OVER THE NORTHERN GREAT LAKES ON THURSDAY NIGHT AND INTO
FRIDAY. THIS LOW AND ASSOCIATED COLD FRONT WILL BRING ANOTHER SHOT
AT SOME RAIN SHOWERS ON THURSDAY NIGHT AND INTO EARLY FRIDAY
MORNING. FOR FRIDAY AND THE WEEKEND...THERE IS INCONSISTENCY
AMONGST THE MODELS IN REGARDS TO THE NEXT WEATHER MAKER. FOR
NOW...HAVE JUST KEPT IN HIGH CHANCE POPS /50 PERCENT/ FOR NEXT
WEEKEND UNTIL THE MODELS CAN GET A BETTER HANDLE ON THE SYSTEM.
ONE THING THAT IS FOR CERTAIN IS THAT TEMPERATURES WILL BE QUITE
WARM /850 TEMPS IN THE 5 TO 10 DEGREE CELSIUS RANGE/ WHICH WILL
RESULT IN PRECIPITATION TO BE ALL RAIN.
MARINE...
WINDS WILL VEER ACROSS THE CENTRAL LAKES REGION TONIGHT AS A WEAK
SURFACE TROUGH PASSES. SPEEDS WILL ALSO DECREASE AS WEAK HIGH
PRESSURE SLIPS IN BEHIND THE TROUGH. SOUTHWEST WINDS WILL RESUME AND
INCREASE ONCE AGAIN ON TUESDAY IN ADVANCE OF THE NEXT SYSTEM THE
RELATIVELY STABLE NEAR SURFACE CONDITIONS WILL KEEP THE WIND IN
CHECK...BUT WILL STILL APPROACH 20KTS WITH SOME GUST POTENTIAL OVER
THE OPEN WATERS AND SAGINAW BAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...DENSE FOG ADVISORY UNTIL 11 AM EST MONDAY FOR MIZ047>049-053>055-
060>063-068>070-075-076-082-083.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
UPDATE.......MR
DISCUSSION...MANN/RK
MARINE.......MANN
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DULUTH MN
349 AM CST MON DEC 7 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 342 AM CST MON DEC 7 2015
CLOUDS AND FOG THE MAIN CONCERN THIS MORNING...WITH A LARGE AREA OF
STRATUS AND FOG OVER THE SOUTHERN HALF TO THIRD OF THE FORECAST
AREA. THE LARGER SCALE MODELS ARE MISSING OUT ON A LOT OF
THIS...BUT THE SHORT RANGE HI RES MODELS ARE PICKING UP ON IT...AND
THE HRRR IS DOING A GOOD JOB WITH THE STRATUS AND FOG THIS MORNING
SO FAR. A WEAK WARM FRONT IS DUE TO MOVE THROUGH THE AREA LATE
THIS AFTERNOON AND TONIGHT. THE STRATUS WE HAVE NOW SHOULD BE
SWEPT NORTHEAST ACROSS THE AREA THROUGH THE REMAINDER OF THE
FORECAST AREA AHEAD OF THE FRONT...AND WHILE MIXING SHOULD HELP
DISSIPATE THE FOG...THE STRATUS SHOULD REMAIN WITH SLIGHTLY HIGHER
CEILINGS DURING THE DAY. THIS STRATUS TO KEEP TEMPERATURES DOWN
AND HAVE PUT THE MAX TEMPERATURE IN THE MIDDLE 30S TO NEAR 40.
TONIGHT AS THE WARM FRONT PASSES THROUGH THE CLOUD COVER SHOULD
KEEP US WARMER THAN THIS MORNING AND EXPECT LOWS IN THE MID 20S TO
NEAR 30...THOUGH THIS MAY BE TOO COLD AND WILL NOT BE SURPRISED IF
WE NEED TO RAISE MORE.
TUESDAY A WEAK SHORTWAVE WILL MOVE INTO THE AREA FROM THE
NORTHWEST... AND MOVE INTO THE FORECAST AREA BY LATE AFTERNOON. THIS
SHOULD BRING SOME CHANCES FOR RAIN TO MAINLY THE SOUTHERN HALF OF
THE FORECAST AREA DURING THE AFTERNOON. FOR NOW IT APPEARS THAT THE
PRECIPITATION SHOULD BE MAINLY RAIN...BUT WILL HAVE TO WATCH SURFACE
TEMPS CLOSELY AS IT COULD BE MIXED WITH SNOW AT TIMES.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 342 AM CST MON DEC 7 2015
RELATIVELY WARM WEATHER THROUGH THE REST OF THE WEEK...THEN FINALLY
COOLING DOWN TO NEAR-SEASONABLE THIS WEEKEND. A FEW CHANCES FOR
PRECIPITATION IN A FAIRLY ACTIVE PATTERN...LIGHT PRECIP TUESDAY
NIGHT THEN MORE SUBSTANTIAL PRECIP AMOUNTS POSSIBLE LATE WED NIGHT
INTO THURSDAY. ANOTHER CHANCE FOR LIGHT PRECIP AMOUNTS THROUGH THE
WEEKEND...WITH A POSSIBLE SHOT AT LAKE EFFECT SNOW ALONG THE SOUTH
SHORE LATE IN THE WEEKEND INTO EARLY NEXT WEEK. ALOFT 850MB TEMPS
ARE WARM AT ABOUT 0 TO +5C THROUGH THE WEEK...THEN FALLING TO A MORE
SEASONABLE -10 TO 0C THIS WEEKEND. /THOUGH THIS IS STILL A BIT ABOVE
NORMAL...INL SOUNDING CLIMATOLOGY AVERAGES AROUND -10C FOR MID
DECEMBER./
TUES NIGHT A WEAK STACKED LOW WILL MOVE SOUTHEAST ACROSS THE UPPER
MIDWEST AS IT TRAVERSES FROM NORTHWEST MINNESOTA INTO NORTHERN
WISCONSIN. THIS LOW WILL BE MAINLY EXITING THE REGION OVERNIGHT
TUESDAY WITH NOT MUCH OF A SURFACE FRONT REFLECTED AT THE SFC. WHILE
LOWS MAY REACH NEAR FREEZING AT THE SFC...ALOFT PROFILES WILL
SUPPORT MAINLY LIGHT RAIN/DRIZZLE...WITH THE SUB-FREEZING TEMPS
ARRIVING AT THE SFC WHEN MID/UPPER LEVELS DRY OUT TOWARDS WED
MORNING. A LOW/MID LEVEL RIDGE BUILDS IN BEHIND THE LOW FOR WED
RESULTING IN SOME CLEARING SKIES BUT NOT BEFORE HIGH CLOUDS BEGIN TO
INCREASE LATE IN THE DAY AHEAD OF THE NEXT SYSTEM.
LATE WED NIGHT INTO THURSDAY WILL BE THE BEST CHANCE FOR
PRECIPITATION ACROSS THE REGION AS A MORE ORGANIZED SYSTEM MOVES
ACROSS THE REGION. MID-LEVEL TROUGH EJECTING OUT OF THE GREAT BASIN
INTO THE NORTHERN HIGH PLAINS WED NIGHT WILL RESULT IN A SFC TROUGH
DEVELOPING IN RESPONSE ACROSS THE RED RIVER VALLEY...WITH A NORTHERN
STREAM UPPER LOW RESULTING IN A SFC LOW ACROSS CENTRAL MANITOBA.
TOWARDS THURSDAY THE BETTER LARGE-SCALE FORCING ARRIVES AS A POTENT
UPPER LOW MOVES ACROSS THE NORTHERN PLAINS AND A SFC LOW DEEPENS
ACROSS THE MN ARROWHEAD DURING THE DAY. SOUTHWESTERLY FLOW AHEAD OF
THE LOW WED NIGHT INTO THURSDAY WILL RESULT IN ABUNDANT MOISTURE AT
LOW/MID LEVELS...CAUSING PRECIPITABLE WATER VALUES TO REACH NEAR
THREE QUARTERS OF AN INCH...NEAR RECORD-BREAKING FOR THIS TIME OF
YEAR. THIS ABUNDANT MOISTURE COMBINED WITH THE WIDESPREAD LARGE-
SCALE LIFT DRIVEN BY THE POTENT UPPER LOW AND WARM AIR ADVECTION
AHEAD OF THE LOW WILL RESULT IN WIDESPREAD PRECIPITATION...MAINLY IN
THE FORM OF RAIN DURING THE DAY THURSDAY....BUT CHANGING TO SNOW
THURSDAY NIGHT AS THE DEEPENING LOW DRAWS IN COLDER AIR FROM THE
NORTHWEST. BY FRIDAY MORNING THE LOW BECOMES STACKED OVER
NORTHERN LAKE SUPERIOR RESULTING IN NORTH TO NORTHWESTERLY FLOW
ACROSS THE NORTHLAND...BRINGING A CHANCE FOR ACCUMULATING SNOWFALL
INTO FRIDAY MORNING BEFORE THE LOW LIFTS OFF THE NORTHWEST. THE
COLD AIR THIS SYSTEM WILL DRAW IN IS STILL VERY WARM...850MB TEMPS
BARELY DIPPING BELOW -5C...SO LAKE EFFECT POTENTIAL LOOKS TO BE
LIMITED.
WHILE THE RAIN/SNOW OCCURS ON THURSDAY INTO FRIDAY MORNING THERE
WILL BE A DEEP LONGWAVE TROUGH DEVELOPING ACROSS THE WESTERN HALF OF
THE LOWER 48...A SIGNIFICANT CHANGE IN THE SYNOPTIC-SCALE PATTERN.
THIS TROUGH WILL DIG DEEPER THAN EARLIER EVENTS THIS LATE FALL/EARLY
WINTER...WITH GUIDANCE LEANING TOWARDS A SLOWER PROGRESSION WHICH
WOULD CAUSE THE STORM TRACK TO BE ALIGNED TOO FAR EAST TO BRING ANY
SIGNIFICANT STORMS ASSOCIATED WITH THIS TROUGH AT LEAST THROUGH THE
WEEKEND. HOWEVER...AS THE LONGWAVE TROUGH DEVELOPS FRIDAY A MID-
LEVEL IMPULSE MOVING ACROSS THE SOUTHWESTERLY FLOW DEVELOPING COULD
RESULT IN A SFC LOW OVER THE UPPER MISSISSIPPI VALLEY FRIDAY INTO
FRIDAY NIGHT...WHICH COULD PULL IN ANOTHER SHOT AT COLDER AIR FROM
CANADA IN ADDITION TO THE CHANCE FOR PRECIPITATION. CONFIDENCE IS
NOT AS HIGH REGARDS TO TIMING...BUT THIS SET UP WOULD SEEM TO FAVOR
LIGHT PRECIP CHANCES INTO THE WEEKEND AS COLDER NORTHWESTERLY FLOW
DEVELOPS IN WAKE OF THIS SFC LOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM CST SUN DEC 6 2015
LIFR/VLIFR WITH BR/FZFG HAS SPREAD TO ALL TERMINALS BUT INL AT THE
OUTSET OF THE FORECAST. LOW CLOUDS WERE MOVING NWD TOWARD
INL...BUT CONFIDENCE WAS LOW ON ADDING ATTM. LATEST HRRR AND RAP
CONTINUE TO INDICATE THE BR/FZFG WILL BEGIN TO LIFT FROM WEST TO
EAST BEGINNING AT 12Z NEAR BRD AND REACHING HYR BY 17Z. VFR IS
THEN EXPECTED UNTIL THE NEXT BATCH OF LOW CLOUDS AND BR ARRIVES
AFTER 18Z WITH MVFR CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 40 29 42 30 / 0 0 20 20
INL 42 28 42 27 / 0 0 30 20
BRD 42 28 43 27 / 0 0 30 20
HYR 43 29 43 30 / 0 10 20 20
ASX 45 32 45 31 / 0 10 20 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 8 AM CST THIS MORNING FOR MNZ034>038.
DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR MNZ025-
026-033.
LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 AM CST TUESDAY
FOR LSZ140.
&&
$$
SHORT TERM...LE
LONG TERM...JJM
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1145 PM CST SUN DEC 6 2015
.UPDATE...
ISSUED AT 944 PM CST SUN DEC 6 2015
DENSE FOG HAS BEEN FORMING/EXPANDING AND PERSISTING FROM CASS AND
SOUTHERN ITASCA EASTWARD TO SOUTHERN ST. LOUIS...CARLTON AND
PINE COUNTIES. EXPIRATION TIMES ARE BASED ON THE LAST FEW RUNS OF
THE HRRR EXP AND RAP WHICH HAVE BEEN VERY CONSISTENT. REST OF THE
FORECAST IN GOOD SHAPE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 246 PM CST SUN DEC 6 2015
STRATUS AND FOG HAS SLOWLY ERODED FROM THE NORTH AND AND WEST
TODAY. STRATUS REMAINED OVER OUR SOUTHERN WISCONSIN COUNTIES AND
ACROSS PORTIONS OF CROW WING...AITKIN...PINE AND CARLTON COUNTIES
IN MINNESOTA AS OF LATE AFTERNOON. THE DIMINISHING TREND SHOULD
CONTINUE FOR A COUPLE MORE HOURS...THEN IT MAY EXPAND AGAIN AFTER
SUNSET. WEAK HIGH PRESSURE WILL MOVE THROUGH THE AREA TONIGHT WITH
LIGHT WINDS THIS EVENING. FOG SHOULD ALSO FORM THROUGH THE
EVENING. THE GRADIENT WILL TIGHTEN OVERNIGHT...MAINLY OVER WESTERN
AREAS. AS THIS OCCURS OVERNIGHT...THE FOG MAY LIFT AND ANY STRATUS
MAY START TO DISSIPATE AS SOME MIXING WITH THE VERY DRY AIR ALOFT
OCCURS. THIS IS MOST LIKELY OVER THE WESTERN HALF OF THE
NORTHLAND.
A SHORTWAVE WILL MOVE IN ON MONDAY AS THE HIGH DEPARTS. AT THIS
TIME...WE HAVE A DRY FORECAST AS MOISTURE IS LACKING AND THE
FORCING IS NOT VERY STRONG. WE DO EXPECT MOSTLY CLOUDY SKIES
THROUGH THE DAY. IT WILL BE MILD WITH HIGHS IN THE UPPER THIRTIES
TO LOWER FORTIES.
ANOTHER SHORTWAVE WILL IMPACT THE REGION ON TUESDAY AND BRING A
CHANCE FOR PRECIPITATION. AT THIS TIME...IT LOOKS LIKE MAINLY
RAIN WILL FALL DURING THE DAY. HIGHS WILL BE IN THE LOWER FORTIES.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 246 PM CST SUN DEC 6 2015
CONTINUED ABOVE NORMAL TEMPERATURES THROUGH MOST OF THE
EXTENDED. HAVE KEPT SMALL POPS FOR RA/SN MIX TUESDAY NIGHT AS AN
850HPA LOW SWEEPS OVER THE REGION. DEPENDING ON THE TIMING OF THE
WAVE/PRECIPITATION...THERE COULD BE A PERIOD OF LIGHT FREEZING
DRIZZLE/RAIN. HOWEVER...PRECIPITATION AMOUNTS LOOK TO REMAIN LIGHT
WITH THIS FAST MOVING SYSTEM.
LONG RANGE MODELS SHOWING A STRENGTHENING LOW PRESSURE SYSTEM WITH
DEEPENING 500HPA LOW...TRACKS ACROSS THE UPPER MIDWEST/WESTERN
GREAT LAKES REGION WEDNESDAY NIGHT/THURSDAY. LATEST GFS AND EC ARE
IN AGREEMENT STRONG WARM AIR ADVECTION ACCOMPANIES THIS
SYSTEM...BRINGING 850HPA WELL ABOVE 0C INTO THE REGION AHEAD OF THE
LOW AND KEEPING PTYPE ALL RAIN. TEMPERATURE PROFILES RAPIDLY COOL
LATE THURSDAY/THURSDAY NIGHT AS THE SYSTEM RETREATS OVER THE GREAT
LAKES AND WINDS TURN OUT OF THE WEST/NORTHWEST. ALTHOUGH TIMING AND
TRACK OF THE LOW VARIES...BOTH MODELS ARE SHOWING THE BULK OF THE
FORCING/PRECIPITATION IS ASSOCIATED WITH THE DEEPENING 850HPA LOW
ALIGNED WITH A 500HPA VORT MAX...WHICH BRINGS CORRIDOR OF QPF IN
EXCESS OF 0.5 INCH AND THE POTENTIAL FOR A FEW INCHES OF SNOWFALL
ACROSS NORTHERN MINNESOTA.
THERE MAY BE A PERIOD FAVORABLE FOR LAKE EFFECT SNOW ALONG THE SOUTH
SHORE OF LAKE SUPERIOR SUNDAY NIGHT/MONDAY AS AN AREA OF 850HPA
TEMPS IN THE NEGATIVE TEENS SPREADS OVER LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1145 PM CST SUN DEC 6 2015
LIFR/VLIFR WITH BR/FZFG HAS SPREAD TO ALL TERMINALS BUT INL AT THE
OUTSET OF THE FORECAST. LOW CLOUDS WERE MOVING NWD TOWARD
INL...BUT CONFIDENCE WAS LOW ON ADDING ATTM. LATEST HRRR AND RAP
CONTINUE TO INDICATE THE BR/FZFG WILL BEGIN TO LIFT FROM WEST TO
EAST BEGINNING AT 12Z NEAR BRD AND REACHING HYR BY 17Z. VFR IS
THEN EXPECTED UNTIL THE NEXT BATCH OF LOW CLOUDS AND BR ARRIVES
AFTER 18Z WITH MVFR CONDITIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 25 40 29 42 / 0 0 0 20
INL 22 42 28 42 / 0 0 0 30
BRD 24 42 28 43 / 0 0 0 30
HYR 22 43 29 43 / 0 0 10 20
ASX 23 45 32 45 / 0 0 10 20
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 8 AM CST MONDAY FOR MNZ034>038.
DENSE FOG ADVISORY UNTIL 6 AM CST MONDAY FOR MNZ025-026-033.
LS...NONE.
&&
$$
UPDATE...GSF
SHORT TERM...MELDE
LONG TERM...GRANING
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1100 PM CST SUN DEC 6 2015
.UPDATED FOR 06Z AVIATION DISCUSSION...
ISSUED AT 1052 PM CST SUN DEC 6 2015
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM CST SUN DEC 6 2015
THE MAIN CONCERN IN THE SHORT TERM IS THE THREAT OF WIDESPREAD DENSE
FOG ACROSS MUCH OF THE FA TONIGHT. AT MID AFTERNOON...A SURFACE HIGH
WAS LOCATED NEAR KSTC. A FEW POCKETS OF DENSE FOG REMAINED UNDER
THE RIDGE AXIS AROUND KLJF...KOVL...KULM. CLEARING EXISTS JUST
WEST OF THESE SITES. THE CONCERN IS THAT THE POCKETS OF DENSE FOG
WILL CONGEAL AND BEGIN TO SPREAD NW THIS EVENING AS LIGHT SE WINDS
DEVELOP ON THE BACKSIDE OF THE HIGH. THE WORST CASE SCENARIO
CONTINUES TO BE FROM THE HRRR WITH WIDESPREAD DENSE FOG SPREADING
IN ALL DIRECTIONS THIS EVENING. THIS HAS BEEN A TREND SEEN SINCE
EARLY THIS MORNING. THE 18Z HOPWRF HAS A SIMILAR SOLUTION EXCEPT
IT DIMINISHES THE FOG IN THE WESTERN CWA LATE TONIGHT. THE 12Z ARW
KEEPS THE DENSE FOG MORE CONFINED TO WHERE IT IS THROUGH THE
EVENING AND THEN BEGINS TO DIMINISH IT DURING THE OVERNIGHT HOURS
AS THE SURFACE WIND FIELD BEGINS TO INCREASE FROM THE SE. MODELED
THE FORECAST MORE TOWARDS THE ARW DUE TO THE INCREASE IN WINDS TO
THE WEST ALONG WITH THE FACT THAT EASTERN MN AND WESTERN WI ARE
ALREADY COVERED IN MVFR/IFR CEILINGS WITH LITTLE RADIATIONAL
COMPONENT SEEN AS WELL AS THE ADVECTIVE COMPONENT HAVING COME TO
AN END. THEREFORE...MENTIONED DENSE FOG FOR THE AFOREMENTIONED
AREA OF CENTRAL/SOUTH CENTRAL MN THROUGH THE EVENING WITH
VISIBILITIES PICKING UP OVERNIGHT.
OTHERWISE...DRY WEATHER THROUGH THE SHORT TERM PERIOD. LOWS TONIGHT
ARE FORECAST TO BE IN THE MIDDLE TO UPPER 20S. THE COLDEST READINGS
ARE FROM MILLE LACS ON EASTWARD WHERE SOME CLEARING MAY REACH IN
FROM THE NORTH LATE TONIGHT. THERE IS PLENTY OF POTENTIAL FOR WARM
HIGHS ON MONDAY. HOWEVER...MUCH DEPENDS ON THE CLOUD COVER AND THE
HEIGHT OF THE MIXING. KEEPING THE MIXING TO 950 MB YIELDS HIGHS IN
THE LOWER TO MIDDLE 40S. AN EXCEPTION IS NEAR KCNB WHERE DOWNSLOPE
WINDS MAY YIELD HIGHS AGAIN IN THE LOWER 50S. RAISING THE MIXING
HEIGHT TO 925 MB INCREASES HIGH TEMPERATURES SOME 5 TO 8 DEGREES CWA
WIDE. OPTED TO STAY WITH THE LOWER MIXING HEIGHT DUE TO THE CLOUD
COVER UNCERTAINTY ALONG WITH THE SNOW COVER OVER THE WESTERN THIRD
OF THE FA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM CST SUN DEC 6 2015
STEADY MILD TEMPERATURES WITH A FEW CHANCES FOR LIGHT/QUICK SHOTS
OF PRECIP ARE THE STORY FOR THE UPCOMING WEEK. AT THIS POINT...THE
DOMINATE PRECIP TYPE IS RAIN.
I COUNT 6-8 SHORTWAVES QUICKLY RIPPLING ACROSS THE NORTHERN CONUS
OVER THE NEXT WEEK. MOST OF THESE WILL HAVE NO MAJOR IMPACTS ON
OUR SENSIBLE WEATHER. THE TWO MORE AMPLIFIED WAVES /ON TUES AND
THURS/ WILL LIKELY BRING LIGHT PRECIP TO OR NEAR THE AREA. THE
FIRST SHORTWAVE MOVES THROUGH ON TUESDAY AND WE HAVE INCREASED
POPS TO FROM 0-10% TO 20-40% DURING THE AFTERNOON AND EVENING. THE
LIMITING FACTOR WITH THIS SYSTEM IS THE ABUNDANCE OF MOISTURE AND
A FAIRLY DRY LOWER ATMOSPHERE BELOW 8000-10000FT. THIS SUGGESTS A
LIGHT QPF EVENT WITH SOME CONCERN IN THE OVERALL PRECIP COVERAGE.
THE FORECAST SOUNDINGS DEPICT A RAIN OR RAIN/SLEET MIX EVEN IF WE
MAXIMIZE OUR WET BULB COOLING...IT SIMPLY LOOKS TOO WARM FOR SNOW
AS THE DOMINANT PRECIP TYPE ON TUESDAY. THE SHORTWAVE SWINGS
THROUGH QUICKLY AND THE PRECIP SHOULD SHUT OFF QUICKLY TUESDAY
NIGHT. LIKE MOST COLD FRONTS THE PAST 3 MONTHS...THE COLD
ADVECTION IS WEAK AND THERE WONT BE MUCH OF A TEMPERATURE
REFLECTION.
WEDNESDAY LOOKS QUIET AND MILD AT THIS POINT...BEFORE ANOTHER
SYSTEM MOVES OUT OF THE GULF OF ALASKA...ACROSS THE PACIFIC
NORTHWEST AND INTO THE FORECAST AREA ON THURSDAY. THIS SYSTEM IS
STRONGER THAN THE TUESDAY SYSTEM AND HAS A BROAD SURFACE LOW IN
THE BALLPARK OF 990MB WHEN IT TRANSVERSES CENTRAL/NORTHERN MN. THE
FORECAST AREA REMAINS ON THE WARM SIDE OF THIS SYSTEM AND SOUTH OF
THE HEAVIER PRECIP AXIS AT THIS POINT.
THE STRONG UPPER JET ACROSS THE PACIFIC BREAKS DOWN LATE THIS WEEK
AND THE CONUS ENDS UP WITH A PRONOUNCED LONGWAVE TROUGH OVER THE
WEST COAST THAT HEADS EAST NEXT WEEKEND. AT THIS POINT...A BAND
OF HEAVY PRECIP WILL LIKELY ACCOMPANY THIS TROUGH...BUT THE MODEL
CONSENSUS IS FORECASTING THE PRECIP WELL SOUTH AND EAST OF THE
FORECAST AREA. THE NUMERICAL GUIDANCE HAS BEEN A LITTLE
INCONSISTENT THE PAST COUPLE DAYS - UNDERSTANDABLE GIVEN HOW FAR
OUT WE ARE. THESE TROUGHS THAT DIG INTO THE SOUTHWEST CONUS AND
THEN LIFT OUT ALWAYS SEEM TO TAKE LONGER THAN WHAT THE MODELS
PREDICT. SO...BRINGING IN PRECIP FRIDAY NIGHT MIGHT BE A LITTLE
AGGRESSIVE AT THIS POINT. STILL A LOT OF UNCERTAINTY IN DAYS 6-8.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1052 PM CST SUN DEC 6 2015
LOW STRATUS AND FOG CONTINUE TO BLANKET THE REGION...AND SEE
LITTLE IN THE WAY OF IMPROVEMENT AS WEAK WINDS KEEP THE MOISTURE
TRAPPED NEAR THE SURFACE. CONDITIONS SHOULD SLOWLY IMPROVE AS
WINDS INCREASE ON MONDAY...BUT THE STRATUS WILL REMAIN FOR MOST OF
THE DAY...IF NOT ALL...UNTIL WESTERLY WINDS BRING DRIER AIR ACROSS
THE REGION.
KMSP...
CEILINGS SHOULD STAY ABOVE 200FT AT KMSP...AND NOT ANTICIPATING
VISBYS TO DROP BELOW 2 MILES DESPITE THE POOR CONDITIONS TO THE
WEST. LIFR CONDITIONS WILL LAST THROUGH AT LEAST THE FIRST PART OF
THE MORNING...AND MAY NEED TO PUSH THEM BACK EVEN FURTHER. WENT
OPTIMISTIC WITH VFR CONDITIONS BY LATE MONDAY EVENING.
/OUTLOOK FOR KMSP/
TUE...MVFR -RA POSSIBLE. WINDS SSW 5-10 KTS.
WED...VFR. WINDS SW 10 KTS.
THU...VFR WITH MVFR/-RA POSSIBLE. WIND W AT 10G20KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 8 AM CST MONDAY FOR MNZ042>045-049>052-
057>059-065>068-073>076-082>084-091-092.
&&
$$
SHORT TERM...RAH
LONG TERM...CLF
AVIATION...JRB
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
922 PM MST SUN DEC 6 2015
.UPDATE...
SHORTWAVE WITH SOME WARM AIR ADVECTION ALOFT WAS MOVING THROUGH
SOUTH CENTRAL MONTANA THIS EVENING AND PRODUCING SOME WEAK ECHOES
TO THE EAST OF BILLINGS...ONCE IT GETS OUT OF THE STRONG DOWNSLOPE
INFLUENCES. HRRR MODEL PICKED UP ON THIS AND PRODUCED SOME VERY
LIGHT QPF WITH THIS FEATURE THIS EVENING. HAVE ADDED SPRINKLES
WITH THIS FEATURE AS LOW LEVELS WERE STILL PRETTY DRY. WINDS HAVE
GUSTED ABOVE 55 MPH FOR SEVERAL HOURS IN LIVINGSTON THIS EVENING
WITH SIMILAR WINDS IN THE UPPER STILLWATER VALLEY. WINDS MAY
ACTUALLY TICK UP A BIT TONIGHT AS THE SURFACE LOW OVER BRITISH
COLUMBIA FLATTENS SOME OF THE HIGHER SURFACE PRESSURES OVER
NORTHERN IDAHO AND NORTHWEST MONTANA...MAKING FOR A MORE FAVORABLE
GRADIENT FOR HIGH WINDS AT LIVINGSTON. WIND FORECAST LOOKS GOOD
AND DID NOT CHANGE. ALSO...MADE SOME MINOR TWEAKS TO TEMPERATURES
OVER THE EAST AS CLOUDS HAVE ROLLED IN AND SLOWED THE COOL DOWN
FOR PARTS OF THE AREA. BAKER IS THE EXCEPTION...AS READINGS HAVE
ALREADY FALLEN INTO THE LOWER 30S THERE. TWH
&&
.SHORT TERM...VALID FOR MON AND TUE...
NO LARGE CHANGES FOR THE AFTERNOON FORECAST PACKAGE. PREVIOUS
MODELS SHOWED THAT KLVM WINDS COULD MEET WARNING CRITERIA LATE MON
INTO MON EVENING. THE 12Z GFS AND LOCAL STUDIES SHOWED THAT
PROBABILITY HAS DROPPED CONSIDERABLY SO NO NEED TO UPGRADE THE
ADVISORY AT THIS POINT. WILL ALSO NOT EXTEND ADVISORY IN TIME AS
THERE WILL BE A RELATIVE LULL IN THE WINDS ON TUE. IN ADDITION...MIXING
POTENTIAL AND GRADIENT ORIENTATION ON MON NIGHT WERE NOT AS
FAVORABLE FOR HIGH WINDS FROM BIG TIMBER TO HARLOWTON WITH THIS
SET OF MODEL RUNS SO WILL NOT ISSUE ANY WATCHES AT THIS TIME.
CROSS-SECTIONS FOR RED LODGE AND KSHR AREAS SHOWED SOME MOUNTAIN
WAVE POTENTIAL FOR MON NIGHT IN BOTH AREAS...AND TUE NIGHT IN RED
LODGE. HOWEVER...THE TIME-FRAMES FOR THESE POSSIBLE HIGH WINDS
WERE VERY SHORT SO CONFIDENCE WAS TOO LOW FOR A HIGHLIGHT FOR
THESE AREAS. DID RAISE WIND SPEEDS IN BOTH LOCATIONS MON NIGHT
HOWEVER.
OTHERWISE...WEAK TROUGH MOVING ACROSS THE REGION WAS GENERATING
MID AND HIGH CLOUDS THIS AFTERNOON ON SATELLITE IMAGERY AND
SURFACE OBSERVATIONS. TEMPERATURES HAD REACHED THE 40S TO AROUND
50 WITH DEWPOINTS REMAINING LOW. KSHR WAS HOLDING IN THE 30S. KEPT
SOME MOUNTAIN POPS IN THE W TONIGHT DUE TO INCOMING PACIFIC
MOISTURE. A FLAT WNW FLOW WILL BE OVER THE AREA ON MON WITH A
CONTINUED CHANCE OF MOUNTAIN PRECIPITATION. PRESSURE FALLS WILL
SPREAD OVER THE AREA FROM W TO E ALLOWING GAP WINDS TO INCREASE
AGAIN. THE PRESSURE FALLS WEAKEN AS THEY CROSS THE REGION MON
NIGHT AHEAD OF A SHORTWAVE. THE WAVE WILL PUSH A WEAK COLD FRONT
THROUGH THE AREA...AND THE PRESSURE GRADIENT WILL BECOME ORIENTED
MORE SW TO NE OVERNIGHT. ADVISORY WINDS WILL CONTINUE FOR KLVM AND
NYE...AND WINDY CONDITIONS WILL SPREAD FURTHER OUT ONTO THE
PLAINS. THE SYSTEM WILL BRING SNOW SHOWERS TO THE SW MOUNTAINS AND
A SLIGHT CHANCE TO CHANCE OF RAIN/SNOW SHOWERS TO AREAS E OF KBIL.
WINDS IN THE GAP AREAS WILL WEAKEN BEHIND THE SYSTEM ON TUE WITH
PRESSURE RISES MOVING THROUGH THE AREA...THEN MORE DISORGANIZED
SHORTWAVE ENERGY WILL APPROACH THE REGION TUE NIGHT WITH
ACCOMPANYING PRESSURE FALLS. THE PRESSURE GRADIENT WILL TURN MORE
N-S AGAIN BRINGING ANOTHER WIND INCREASE TO THE GAP FLOW AREAS.
LINGERED POPS OVER THE E ON TUE MORNING WITH THE DEPARTING
SYSTEM...OTHERWISE HAD CHANCE MOUNTAIN POPS OVER THE W THROUGH TUE
NIGHT. TUE WILL BE AN EVEN WARMER DAY WITH 850 MB TEMPERATURES
AROUND +10 DEGREES C. ARTHUR
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
STRONG WESTERLY FLOW ALOFT ON WEDNESDAY BEGINS TO WEAKEN THURSDAY
NIGHT WITH BROAD TROUGHING DEVELOPING OVER THE WESTERN US FRIDAY
INTO SATURDAY. ANOTHER ROUND OF STRONG WEST NORTHWEST FLOW ALOFT
REPLACES THIS LULL DURING THE WEEKEND AND MODELS DIFFER ON TIMING.
MODELS SHOW A STRONGER PULSE OF WIND SPREADING ACROSS THE PLAINS
ON WEDNESDAY AS A COLD FRONT MOVES THROUGH THE REGION WITH 850MB
WINDS PROGGED TO REACH 30KTS AND MEX GUIDANCE SHOWING EVEN
STRONGER WINDS. EXPECT THE VERY STRONG GAP FLOW WINDS TO BE
CONTINUING AT THIS TIME AS WELL AS THE FRONT IS QUICKLY FOLLOWED
BY ANOTHER WAVE JUMPING INTO THE LEESIDE TROUGH. MAY SEE LESS OF A
GAP FLOW PATTERN AND MORE OF A STRONG WIND PATTERN FOR BIG TIMBER
AND HARLOWTON AREAS BUT TIMING WILL PLAY A ROLE SO KEPT GAP FLOW
WIND SPEEDS THE SAME AND RAISED WINDS OVER THE PLAINS. STILL
BREEZY ON THURSDAY BUT GAP FLOW WINDS WILL DECREASE AND DEFINITELY
LESS WIND ACROSS THE REGION FRIDAY AND SATURDAY...POSSIBLY
RETURNING SUNDAY.
PRECIPITATON IN THE WESTERLY FLOW WILL CONTINUE TO IMPACT WEST
FACING ASPECTS BUT SHOWER ACTIVITY REACHING THE PLAINS AND WILL
NOT AMOUNT TO MUCH...AND MAY FOR THE MOST PART FALL AS RAIN
SHOWERS WEDNESDAY. TEMPERATURES ON WEDNESDAY WILL BE IN THE 50S
BEFORE A COOLING TREND THURSDAY INTO THE WEEKEND BUT COOLING ONLY
TO NORMAL FOR THIS TIME OF YEAR. BORSUM
&&
.AVIATION...
STRONG GAP FLOW WINDS WILL PERSIST AT KLVM AND ALONG THE FOOTHILLS
WITH GUSTS OF 40KT OR GREATER THROUGH MONDAY. VFR CONDITIONS WILL
PREVAIL WITH SOME HIGHER MOUNTAIN OBSCURATIONS IN SNOW SHOWERS.
BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 032/051 038/057 041/058 033/048 029/041 026/040 025/041
00/N 11/N 12/W 22/W 31/B 21/E 11/E
LVM 035/048 043/054 046/052 031/045 026/036 022/034 021/036
11/N 32/W 14/W 23/W 31/N 21/N 12/J
HDN 026/053 034/058 037/062 031/050 027/043 022/041 021/043
00/U 22/W 11/B 31/N 31/B 22/W 12/W
MLS 030/053 033/057 037/062 034/050 027/042 022/038 019/041
10/U 32/W 12/W 21/N 21/B 12/W 11/B
4BQ 029/054 032/060 033/062 031/051 028/043 022/039 020/042
10/U 22/W 11/B 30/N 22/W 22/W 11/N
BHK 024/051 030/053 032/060 033/049 026/040 019/035 017/038
10/U 32/W 12/W 31/N 22/W 12/J 11/B
SHR 024/052 031/057 033/062 029/052 025/040 020/038 017/041
00/U 11/B 11/B 11/N 32/W 22/W 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL MIDNIGHT MST MONDAY NIGHT FOR
ZONES 65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
343 AM CST MON DEC 7 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
MAIN NEAR TERM CONCERN CONTINUES TO BE AN EXTENSIVE AREA OF DENSE
FOG ACROSS OUR WESTERN IOWA COUNTIES WHERE WE ALREADY HAVE A DENSE
FOG ADVISORY. SATELLITE IMAGERY SHOWS THIS CONTINUING INCH TO THE EAST
HOWEVER HIGH CLOUDS SPILLING OVERHEAD ARE MAKING IT TOUGH TO SEE
THE LOWER CLOUDS/VISIBILITIES. CALLS TO A FEW COUNTIES
ACKNOWLEDGED SOME ICE/FROST ON VEHICLES AND GRASSY SURFACES BUT SO
FAR NO IMPACTS ON ROADS WITH ROAD TEMPERATURES STILL IN THE UPPER
30S. BOTH HRRR AND RAP INDICATE THE FOG/STRATUS DECK RAPIDLY
SLIDING EAST OF THE CWA BY MID MORNING. DID REMOVE MONONA COUNTY
FROM THE ADVISORY AND EXTENDED THE REMAINDER OF THE ADVISORY UNTIL
14Z.
OTHERWISE...LATEST WATER VAPOR IMAGERY LOOP SHOWS A WEAK SHORTWAVE
TROUGH EXTENDING FROM EASTERN MT THROUGH NORTH CENTRAL COLORADO. AT
THE SURFACE...A TROUGH EXTENDS SOUTH FROM LOW PRESSURE OVER SOUTH
CENTRAL CANADA INTO WESTERN KANSAS AND EVENTUALLY THE TEXAS
PANHANDLE. THE WEAK SHORTWAVE WILL CONTINUE TO MOVE EAST THROUGH
NEBRASKA TODAY AND INTO THE GREAT LAKES REGION BY EARLY TONIGHT.
THE SFC TROUGH PASSAGE WILL BE BRIEF/WEAK AND SHOULD HAVE LITTLE
AFFECT ON ANY SENSIBLE WEATHER EXCEPT FOR A BRIEF/WEAK WIND SHIFT
THIS AFTERNOON FROM SOUTHWEST TO NORTHWEST.
MILD CONDITIONS WILL BE THE PRIMARY STORY THIS WEEK WITH
TEMPERATURES RUNNING CLOSE TO 15 TO EVEN 20 DEGREES ABOVE NORMAL.
ANOTHER MID LEVEL SHORTWAVE WILL DRIFT THROUGH THE AREA TUESDAY
WHICH BRINGS INCREASED LARGE SCALE LIFT...BUT LACK OF MOISTURE
KEEP POPS OUT OF THE FORECAST. MAY ONLY SEE AN INCREASE IN
HIGH/MID CLOUDS BUT A FEW SPRINKLES CANNOT BE COMPLETELY RULED
OUT. AN ASSOCIATED SFC TROUGH WILL PUSH THROUGH TUESDAY AFTERNOON
TURNING WINDS AGAIN FROM SOUTHWEST TO NORTHWEST WHICH SHOULD ALLOW
DECENT MIXING TO PUSH HIGHS INTO THE MID TO UPPER 50S...WITH SOME
LOWER 60S POSSIBLE ACROSS OUR SOUTHERN COUNTIES DEPENDING ON
EXTENT OF CLOUD COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
PATTERN BECOMES MORE ACTIVE TOWARD THE WEEKEND WHEN A DEEP TROUGH
DIGS ACROSS THE WESTERN STATES AND A FAIRLY TIGHT BAROCLINIC ZONE
SETS UP ACROSS THE NATION`S MID SECTION BY FRIDAY. THIS CONTINUES
TO LOOK LIKE A LOW QPF EVENT FOR OUR CWA AS MAIN RIBBON OF QPF
DEVELOPS ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTHEAST BY
SATURDAY NIGHT/EARLY SUNDAY. MAIN PCPN FOR OUR AREA MIGHT BE SOME
OVERRUNNING...BUT DETAILS THIS FAR OUT ARE STILL A LITTLE SKETCHY.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1123 PM CST SUN DEC 6 2015
THE CONCERN IS WHETHER A DECK OF STRATUS ABOUT 200 FEET AGL AND
VISIBILITY LESS THAN 1/4...WHICH IS ABOUT 18 MILES EAST OF
KOMA... WILL MAKE IT THE SITE OR NOT. HRRR/RAP MODEL CONTINUES TO
SUGGEST THIS WHILE OTHER MODELS DO NOT. FOR NOW HAVE INCLUDED A
TEMPO GROUP AT KOMA WITH 2SM AND SCT005 FROM 07-11Z...AND WILL
UPDATE IF NEEDED. OTHERWISE...IT`S A VFR FORECAST WITH BROKEN TO
SCATTERED CIRRUS. LIGHT SOUTH SOUTHEAST WINDS NOW...VEERING TO
WEST SOUTHWEST THROUGH THE MORNING.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...DENSE FOG ADVISORY UNTIL 8 AM CST THIS MORNING FOR IAZ055-056-
069-079-080-090-091.
&&
$$
SHORT TERM...KERN
LONG TERM...KERN
AVIATION...DEWALD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1142 PM CST SUN DEC 6 2015
.UPDATE...
ISSUED AT 1136 PM CST SUN DEC 6 2015
BROAD 500 MB SHORT WAVED TROUGH MOVING INTO WRN MANITOBA AND THE
WRN DAKOTAS AT 0530 UTC. AREA OF HIGH CLOUDS AHEAD OF IT OVER THE
AREA. LOW CLOUDS AND FOG HANGING JUST EAST AND SOUTHEAST...THOUGH
HAVE MOVED INTO SE WADENA COUNTY (STAPLES). HAVENT MUCH ADVANCE
NORTHWEST LAST HOUR OR TWO...BUT LOW CLOUDS ARE BEING MASKED BY
HIGH CLOUDS NOW. WITH HIGH CLOUDS MOVING OVER THE LOW CLOUD/FOG
AREA IT IS HOPED THE FOG WILL DISSIPATE SOME. WRN EDGE OF LOW
CLOUDS MAY YET PARTS OF THE FAR ERN FCST AREA. OTHERWISE CIRRUS
AND A SOUTH BREEZE. TEMPS HAVE BEEN HOLDING STEADY SINCE THEIR
DROP IN THE EARLY EVENING AND EXPECT TO SEE NOT A LOT OF TEMP
CHANGE OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM CST SUN DEC 6 2015
THE MAIN CHALLENGE WILL BE TEMPS AND QPF CHANCES TUE INTO TUE
NIGHT. MODELS ARE IN FAIRLY GOOD AGREEMENT...WITH SOME TIMING AND
PLACEMENT ISSUES WITH QPF TUE/TUE NIGHT. WE PREFER THE GFS THAT
HAS A DECENT HANDLE ON CURRENT SET UP.
FOR TONIGHT...SOUTHERLY WINDS SHOULD REMAIN NEAR 10KT FOR ALL BUT
THE FAR EAST. THE HRRR INDICATES SOME FOG ONCE AGAIN IN THE FAR
EAST SO WILL ADD. TEMPS WILL CONTINUE WELL ABOVE NORMAL.
ON MONDAY...ANOTHER VERY MILD DAY WITH WESTERLY FLOW ONCE AGAIN.
TEMPS SHOULD BE SIMILAR TO TODAY AND MAY EVEN BE A BIT WARMER WITH
MORE WESTERLY WINDS NEAR THE SFC.
FOR MONDAY NIGHT...CLOUDS WILL INCREASE IN THE WEST LATE AND WINDS
SHOULD REMAIN MIXED ENOUGH TO KEEP TEMPS NEAR 30.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM CST SUN DEC 6 2015
FOR TUE...A SHORTWAVE MOVES THROUGH WITH SOME RAIN...FREEZING RAIN
EARLY TRANSITIONING TO RAIN FAIRLY QUICKLY. THE GFS HAS SOME QPF
SOUTH WITH THE NAM FURTHER NORTH...WITH THE ECMWF MORE
BROADBRUSHED QPF.
ON TUE NIGHT...ANY PRECIP WILL MOVE INTO THE EAST. IT SHOULD BE
MAINLY RAIN THAT COULD MIX WITH A FEW FLAKES BEFORE ENDING.
ON WED...MORE VERY WARM CHINOOK MODIFIED AIR MOVES IN. TEMPS
SHOULD BE INTO THE 40S PERHAPS EVEN WARMER FOR AREAS THAT HAVE NO
SNOW.
FOR WEDNESDAY NIGHT THROUGH SUNDAY...MODELS DEPICT A MUDDY ZONAL
FLOW PATTERN THROUGH THE MIDWEEK PERIOD WITH A TRANSITION TO A
DEEP CENTRAL CONUS TROF FOR THE WEEKEND. THUS WILL EXPECT
SEASONABLY MILD CONDITIONS AND PERIODS OF LIGHT RAIN CHANGING TO
SNOW LATE ON THURSDAY... WITH A TURN TO SOMEWHAT COOLER CONDITIONS
AND A GREATER CHANCE FOR WIDEPSREAD LIGHT SNOW FROM LATE FRIDAY
INTO SUNDAY. SNOWFALL AMOUNTS ARE STILL EXPECTED TO REMAIN SCANT
AT LEAST THROUGH SATURDAY... SO NET IMPACTS OF THE EXPECTED LIGHT
SNOW ON OVERALL TEMPERATURE PATTERNS SHOULD BE SLIGHT. THUS WILL
CONTINUE TO BUMP TEMPERATURES AROUND 10 DEGREES ABOVE LONG TERM
NORMALS YET ON SATURDAY /EXPECTED HIGHS NEAR THE FREEZING POINT/
AND AROUND 5 DEGREES ABOVE NORMAL ON SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1136 PM CST SUN DEC 6 2015
VFR THRU THE PD WITH CIRRUS MOVING THROUGH. THICKEST OVERNIGHT
WITH THIN OR CLEAR PATCHES MONDAY MIDDAY INTO THE AFTN/EVE. SOUTH
WINDS 5 TO 15 KTS WILL BECOME WEST-SOUTHWEST WEST OF THE RRV
MONDAY AFTN. ONLY QUESTION YET IS BEMIDJI AREA AS WRN FRINGE OF
LOW CLOUDS AND FOG MAY IMPACT THE AREA FOR A TIME LATE NIGHT OR
EARLY MONDAY MORNING. INCLUDED A TEMPO GROUP 09-13Z UTC FOR SOME
MVFR VSBY IN FOG AND SCATTERED LOW CLOUD AT BJI TAF SITE. NOT
ENOUGH CONFIDENCE TO GO IFR CIGS...THOUGH A PD WOULD NOT BE
SUPRISING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...DK
LONG TERM...GUST/DK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
114 AM EST MON DEC 7 2015
.SYNOPSIS...
WEAK LOW PRESSURE WILL MOVE THROUGH THE REGION OVERNIGHT INTO
MONDAY. HIGH PRESSURE WILL BUILD BACK IN FOR TUESDAY. ANOTHER LOW
PRESSURE SYSTEM WILL AFFECT THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
CLOUDS ARE BECOMING THE KEY ELEMENT TO THE FORECAST
TONIGHT...FORCING A FEW CHANGES THIS EVENING. CURRENT SATELLITE
IMAGERY SHOWS CIRRUS DEPARTING OHIO AND KENTUCKY TO THE
EAST...WITH A BROKEN DECK OF MID CLOUDS (8KFT-12KFT) EXTENDING
ACROSS SOUTHERN MICHIGAN...NORTHEASTERN INDIANA...AND WESTERN
OHIO. BEHIND THIS...A SOLID DECK OF STRATOCUMULUS (3KFT-6KFT) IS
PERHAPS THE MOST EASILY DISTINGUISHED OF THE FEATURES ON THE
11U-3.9U SATELLITE PRODUCT. THIS CLOUD DECK HAS JUST ENTERED THE
FORECAST AREA...IN ADVANCE OF THE WEAK SURFACE AND MID-LEVEL LOW
PRESSURE CENTERS...AND WILL CONTINUE TO SPREAD INTO OHIO AND
KENTUCKY OVER THE NEXT SEVERAL HOURS.
AHEAD OF THESE CLOUDS...TEMPERATURES HAVE TAKEN A REMARKABLY QUICK
TURN FOR THE BASEMENT IN CENTRAL OHIO...WITH VALUES ALREADY
SEVERAL DEGREES BELOW FREEZING EAST OF COLUMBUS. UNTIL THE CLOUDS
GET INTO THE REGION...THESE TEMPERATURES SHOULD CONTINUE TO DROP.
HOWEVER...CONDITIONS UNDER THE STRATOCUMULUS DECK HAVE BEEN QUITE
A BIT WARMER...WITH TEMPERATURES NEAR 40 IN CENTRAL INDIANA...AND
IN THE MID 40S IN WEST-CENTRAL INDIANA. A COMPLETELY NEW SET OF
TEMPERATURE GRIDS HAS BEEN CREATED...INDICATING STEADY
TEMPERATURES IN THE WESTERN HALF OF THE CWA...AND SOME ADDITIONAL
COOLING IN THE EAST BEFORE RISING AGAIN AFTER 06Z. SKY GRIDS WERE
ALSO ADJUSTED TO INCREASE VALUES ONCE THE STRATOCUMULUS DECK
ARRIVES.
PRECIPITATION AMOUNTS TO THE WEST HAVE BEEN VERY LIGHT...WITH
GENERALLY TRACE TO 0.02" REPORTS ON THE HOURLY OBSERVATIONS. THE
AREA OF SHOWERS MAY EXPAND VERY SLIGHTLY IN COVERAGE AND
INTENSITY OVER THE NEXT FEW HOURS...BUT THE CHANCES OF MEASURABLE
PRECIPITATION FOR THE ILN FORECAST AREA STILL SEEM WELL COVERED BY
THE CURRENT ARRANGEMENT OF POPS. BASED ON RADAR TRENDS...THE POPS
WERE ADJUSTED NORTHWARD BY ONE OR TWO TIERS OF COUNTIES. A TIMING
COMPROMISE BETWEEN THE HRRR (SLIGHTLY FAST) AND NAM/GFS (SLIGHTLY
SLOW) MATCHED WELL WITH THE PREVIOUS FORECAST...AND WAS RETAINED.
A WARM LAYER AT AROUND 950MB WILL ENSURE THAT PRECIPITATION THAT
FALLS REMAINS LIQUID...THOUGH SURFACE TEMPERATURES AT ONSET MAY BE
IN THE MID 30S.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
UPPER LOW MOVES ACROSS THE CWA MONDAY MORNING. CONTINUED LOW POPS
ACROSS THE SOUTHEAST PORTION OF THE CWA UNTIL THE LOW EXITS.
BEHIND IT...ENOUGH DRYING IN THE MID LEVELS ALONG WITH SUBSIDENCE
FROM WEAK HIGH PRESSURE WILL ALLOW FOR SOME SUNSHINE TO RETURN
FOR THE AFTERNOON AND THAT WILL KEEP MAXIMA ABOVE AVERAGE FOR THIS
TIME OF THE YEAR.
HIGH PRESSURE MOVES TO THE EAST MONDAY NIGHT...AND SOUTHERLY FLOW
AROUND THE HIGH WILL LIKELY BRING AN INCREASE IN CLOUDS MONDAY
NIGHT BUT IT SHOULD REMAIN DRY.
GENERALLY ZONAL FLOW ALOFT WILL BE IN PLACE TUESDAY/TUESDAY
NIGHT WITH DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AN UPPER LEVEL S/WV WILL TRAVERSE OUR REGION ON WEDNESDAY. THIS
FEATURE...ALONG WITH A SFC TROF AXIS...WILL BRING A CHANCE OF
SHOWERS. SYSTEM MOVES EAST WEDNESDAY NIGHT...FOLLOWED TO A RETURN OF
DRY WEATHER ON THURSDAY.
THE FORECAST IS STILL A LITTLE BIT UNCLEAR AS WE HEAD INTO THE END
OF THE WEEK...ESPECIALLY IN REGARDS TO AREAL COVERAGE AND
PROBABILITY OF PCPN. THE FLOW DOES BECOME MORE AMPLIFIED WITH A
LARGE SCALE MID LEVEL TROUGH DIGGING OUT FROM THE WESTERN U.S. AND
RIDGING DEVELOPING OVER THE EASTERN U.S. S/WV ENERGY FOR
THURSDAY/FRIDAY STILL VARYS AMONGST THE MODELS IN TERMS OF HOW
STRONG/DEEP IT WILL BE AS IT PASSES THROUGH THE GREAT LAKES. HAVE
KEPT POPS ON THE LOW SIDE DUE TO HIGH UNCERTAINTY. FOR
SATURDAY...LOOKS LIKE MID LEVEL RIDGING AND A WARM FRONT WILL LIFT
THROUGH OUR REGION. WARMER TEMPERATURES AND SOME WAA SHOWERS WILL BE
POSSIBLE. LOW PRESSURE AND A SLOW MOVING COLD FRONT WILL ENCROACH
THE REGION ON SUNDAY WITH A HIGHER THREAT FOR SHOWERS EXPECTED.
IT WILL CONTINUE TO BE WARMER THAN NORMAL THROUGH THE PERIOD WITH
TEMPERATURES WARMING INTO THE 60S BY THE WEEKEND...WHICH IS SOME 20
DEGREES ABOVE NORMAL FOR MID DECEMBER. THESE VALUES MAY CHALLENGE
RECORD HIGHS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE AREA OVERNIGHT AND
INTO THE MORNING HOURS ON MONDAY. LIGHT RAIN SHOWERS WILL MOVE
ACROSS THE AREA. VSBYS WILL GENERALLY STAY VFR HOWEVER VSBYS MAY
BRIEFLY BE REDUCED WITH FOG AND SHOWER ACTIVITY. SHOWER ACTIVITY
WILL MOVE OUT DURING THE MORNING HOURS. CLOUD COVER WILL DECREASE
DURING THE DAY ON MONDAY. WINDS WILL BE LIGHT AND LESS THAN 10
KNOTS THROUGH THE TAF PERIOD.
THERE ARE INDICATIONS OF POSSIBLE FOG AND STRATUS DEVELOPMENT
MONDAY NIGHT. WENT MORE WITH A FOG SOLUTION HOWEVER WENT WITH
SCATTERED LOWER CLOUDS AT THE LONGER KCVG TAF SITE. IN ADDITION
BROUGHT DOWN VSBYS AT THE LONGER KCVG TAF OVERNIGHT MONDAY NIGHT.
OUTLOOK...MVFR AND POSSIBLY IFR VSBYS ARE POSSIBLE MONDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BPP
NEAR TERM...HATZOS
SHORT TERM...BPP
LONG TERM...HICKMAN
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
449 AM EST MON DEC 7 2015
.SYNOPSIS...
A MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS
SOUTHERN PA LATE TODAY. A SERIES OF LOW PRES SYSTEMS WILL TRACK
WELL WEST OF PA LATE IN THE WEEK...AS AN ANOMALOUS UPPER RIDGE
BUILDS ALONG THE EAST COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9U LOOP AT 0830Z SHOWING AREAS OF DENSE VALLEY FROM EXTENDING
FROM THE CENTRAL MTNS EASTWARD INTO THE SUSQ VALLEY. STRONG
INVERSION AND LOW DECEMBER SUN ANGLE WILL ALLOW FOG TO PERSIST
THROUGH LATE AM...COVERED BY DENSE FOG ADV THRU 16Z.
APPROACHING UPPER LOW IS PRODUCING A BATCH OF SHOWERS ACROSS THE
OHIO VALLEY AT 09Z. HOWEVER...ALL NEAR TERM MDL GUIDANCE TRACKS
WEAKENING SFC LOW WELL SOUTH OF PA...WITH AIR MASS OVR PA
REMAINING TOO DRY TO SUPPORT PRECIP. THEREFORE...WILL CONTINUE TO
CARRY ONLY A SLIGHT CHC OF SHOWERS ACROSS SOMERSET/BEDFORD
COUNTIES LATER TODAY.
UPSTREAM SATL IMAGERY AND MDL RH FIELDS SUGGEST PATCHY AM
FOG WILL GIVE WAY TO MSUNNY SKIES ACROSS MOST OF CENTRAL PA.
EXCEPTION WILL BE SOMERSET/BEDFORD COS...WHERE INCREASING CLOUDS
EXPECTED THIS AFTN. HIGHS WILL BE FAIRLY UNIFORM...RANGING FROM
45-50F OVER MOST OF THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
UPPER LOW WILL PUSH EAST OF PA TONIGHT...AS SFC RIDGE BUILDS IN
FROM THE NORTHWEST. MCLEAR SKIES AND A NEARLY CALM WIND SHOULD
ONCE AGAIN PROMOTE AREAS OF LOW CLOUDS/FOG. WEAKEST GRADIENT AND
REGION MOST FAVORABLE FOR FOG WILL BE ACROSS THE ALLEGHENY PLATEAU
WITH ONLY PATCHY FOG LIKELY FURTHER EAST ACROSS THE SUSQ VALLEY.
SFC RIDGE OVR THE REGION SHOULD ENSURE A DRY TUESDAY WITH PASSING UPPER
LVL SHORTWAVE LIKELY TO PRODUCE NO MORE THAN SCT MID/HIGH LVL
CLOUDINESS. SUPERBLEND AND NEW ECME MOS INDICATE HIGHS IN THE 40S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MAIN FORECAST STORY THRU THE END OF THIS WEEK IS THE
CONTINUED MILD TEMPERATURES...AS ZONAL FLOW FLOODS THE CONUS WITH
PACIFIC AIR. NAEFS AND ECENS OUTPUT SHOWING A SERIES OF SFC LOWS
TRACKING NORTHWARD THRU THE GRT LKS LATE NEXT WEEK...AS ANOMALOUS
UPPER RIDGE BUILDS ALONG THE E COAST. HAVE INCLUDED A CHC OF SHRA
ASSOC WITH SHORTWAVE LIFTING UP THE OHIO VALLEY LATE WED/EARLY
THU. OTHERWISE...THE EXTENDED FCST APPEARS DRY AND INCREASINGLY
WARM BENEATH BUILDING RIDGE.
GEFS PLUME DATA AND ECEME MOS SUPPORT MIN TEMPS ABOVE FREEZING
ACROSS THE ENTIRE CWA THU-SUN AND MAX TEMPS AT LEAST 15F ABV
NORMAL.
SOME CHC OF SHOWERS TOWARD THE END OF THE FCST PERIOD...AS
SOUTHERN STREAM SHORTWAVE LIFTS THRU THE GRT LKS...PUSHING A COLD
FRONT INTO PA. LATEST GEFS OUTPUT SUGGESTS FRONT AND SHOWER THREAT COULD
ARRIVE BY SUNDAY...WHILE ECENS IS A SLOWER SOLUTION WITH DRY/VERY
WARM WX PERSISTING THRU SUNDAY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
THE BIGGEST FORECAST QUESTION OVERNIGHT IS FOG FORMATION. CURRENT
HRRR AND RAP RUNS DECREASE THE FOG THROUGH MOST OF THE CENTRAL PA
BY 09Z...HOWEVER GIVEN THE LOW DEWPOINT DEPRESSIONS...CALM WINDS
AN STRONG INVERSION EXPECT CENTRAL TAF SITES AOO...UNV...IPT TO
SEE IFR AND LOWER CIGS AND VSBYS OVERNIGHT UNTIL MORNING. THERE
HAS BEEN SOME VARIABILITY IN VSBYS DUE TO THE FOG MOVEMENT.
EXPECT TEMPO GROUPS OF 1/4 MILE AT TIMES AT UNV AND AOO...AND MVFR
RESTRICTIONS DUE TO THE PATCHY NATURE OF THE FORMING FOG THROUGH
THE FIRST HALF OF THE OVERNIGHT HOURS. AS THE FOG/MIST BECOMES
ENTRENCHED BETWEEN 06Z TO 09Z...VSBYS WILL DECREASE AND REMAIN IFR
AND LOWER.
MAINLY VFR CONDS WILL PREVAIL AT JST AND BFD...DUE TO
THE DRY NW FLOW ALOFT. FOG/MIST THROUGH THE LOWER SUSQ IS AN
INTERESTING CONUNDRUM. THOUGH SOME HIGH CLOUDS PERSIST...CALMING
WINDS...DEWPOINT DEPRESSIONS OF CURRENT 4 DEGREES OR LESS...SHOULD
ALLOW FOR FOR DENSE FOG OVERNIGHT. EXPECT PERIODS OF IFR VSBYS AND
LOWER ESPECIALLY NEAR SUNRISE. THE FOG WILL SLOWLY LIFT/DISSIPATE
TOMORROW MORNING...THOUGH QUICKER THAN IT DID ON SUNDAY. SO
EXPECT VFR TO RETURN BY 15Z MON AT ALL SITES.
A MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS
THE AREA MONDAY...POTENTIALLY BRINGING RESTRICTIONS TO KJST LATER
MONDAY AND SPREADING INTO MAINLY THE SOUTHERN HALF OF THE STATE
MON NIGHT.
OUTLOOK...
MON-MON NIGHT...CHANCE FOR MVFR CONDITIONS IN -SHRA ACROSS THE
SOUTHERN HALF OF PENN.
TUE...NO SIG WX EXPECTED.
TUE NIGHT-WED NIGHT...CHANCE FOR MVFR CIGS.
THU-FRI...MVFR POSS NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR PAZ012-
017>019-025>028-034>036-041-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
117 AM EST MON DEC 7 2015
.SYNOPSIS...
AN UPPER LEVEL LOW DROPPING SE FROM THE OHIO VLY MAY BRING
A FEW SHOWERS TO SOUTHERN PA ON MONDAY. ANOTHER UPPER LEVEL
LOW MOVING ACROSS THE GREAT LAKES ON WED MAY BRING A FEW MORE
SHOWERS TO THE AREA LATER WED INTO THU. OTHERWISE HIGH PRESSURE
OVER THE SE STATES WILL KEEP DRY AND MILD CONDITIONS ACROSS
THE KEYSTONE STATE THIS WEEK. HIGH TEMPERATURES WILL AVERAGE
WELL ABOVE NORMAL FOR EARLY DEC.
&&
.NEAR TERM /UNTIL 10 AM THIS MORNING/...
SFC OBS AT 06Z INDICATING PATCHY DENSE FOG FROM THE CENTRAL MTNS
EASTWARD. VEIL OF HIGH CLOUDS SHOULD BE SHIFTING EAST OF THE AREA
BTWN 07Z-09Z...LEADING TO ADDITIONAL RAD COOLING AND MORE
EXTENSIVE FOG TOWARDS DAWN. NO CHANGES EXPECTED TO CURRENT DENSE
FOG ADVISORY...WHICH COVERS ALL BUT THE N MTNS AND LAUREL
HIGHLANDS.
DWPT DEPRESSIONS ALREADY QUITE LOW...SO EXPECT ONLY ANOTHER COUPLE
DEG DROP IN TEMPS BTWN 06Z-12Z WITH MINS OF 25-30F OVER MOST OF
CENTRAL PA.
&&
.SHORT TERM /10 AM THIS MORNING THROUGH 6 PM TUESDAY/...
MOISTURE CHALLENGED UPPER TROF CRASHING INTO AND DISPLACING THE
EAST COAST UPPER RIDGE WILL MOVE OVER WESTERN AND CENTRAL PA ON
MONDAY...BRINGING CONSIDERABLE CLOUDINESS ACROSS SW PA BUT LITTLE
ELSE IN THE WAY OF SENSIBLE WEATHER AFTER ANOTHER ROUND OF MORNING
VALLEY FOG. THINK THE ONLY AREA TO SEE SHOWERS FROM THIS SYSTEM
WILL BE THE LAUREL HIGHLANDS...AS BOUNDARY LAYER IS JUST TOO DRY
TO SUPPORT MUCH PRECIPITATION FARTHER EAST. CLOUDS WILL BE
THICKEST OVER THE LAUREL HIGHLANDS AS WELL...WITH MOSTLY CLOUDY
SKIES SEEN THERE... WHILE THE REMAINDER OF CENTRAL PA RANGES FROM
P/S TO M/S. HIGHS WILL BE FAIRLY UNIFORM...RANGING FROM THE UPPER
40S TO THE LOWER 50S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MAIN FORECAST STORY FOR THE EXTENDED PERIOD IS THE CONTINUED
MILD TEMPERATURES...AS ZONAL FLOW FLOODS THE CONUS WITH PACIFIC
AIR. NAEFS AND ECENS OUTPUT SHOWING A SERIES OF SFC LOWS TRACKING
NORTHWARD THRU THE GRT LKS LATE NEXT WEEK...AS ANOMALOUS UPPER
RIDGE BUILDS ALONG THE E COAST. HAVE INCLUDED A CHC OF SHRA ASSOC
WITH SHORTWAVE LIFTING UP THE OHIO VALLEY LATE WED/EARLY THU.
OTHERWISE...THE EXTENDED FCST APPEARS DRY AND INCREASINGLY WARM
BENEATH BUILDING RIDGE.
GEFS PLUME DATA AND ECEME MOS SUPPORT MIN TEMPS ABOVE FREEZING
ACROSS THE ENTIRE CWA THU-SAT AND MAX TEMPS AT LEAST 15F ABV
NORMAL.
MAIN CHANGE WAS TO EDGE TEMPS UP A LITTLE.
ALSO MORE FOG COULD FORM TUESDAY MORNING...AS SKIES CLEAR.
THUS I ADDED PATCHY FOG.
ICE FOG ON A LOT OF OBJECTS EARLY TODAY.
A BIG CHANGE FROM THE LAST 2 WINTERS...ENJOY THE GOOD WEATHER
WHILE IT LAST.
FOR NEXT WEEKEND...STILL MILD...BUT SOME CHC OF SHOWERS BY
SUNDAY. WENT WITH CHC POPS FOR NOW.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
THE BIGGEST FORECAST QUESTION OVERNIGHT IS FOG FORMATION. CURRENT
HRRR AND RAP RUNS DECREASE THE FOG THROUGH MOST OF THE CENTRAL PA
BY 09Z...HOWEVER GIVEN THE LOW DEWPOINT DEPRESSIONS...CALM WINDS
AN STRONG INVERSION EXPECT CENTRAL TAF SITES AOO...UNV...IPT TO
SEE IFR AND LOWER CIGS AND VSBYS OVERNIGHT UNTIL MORNING. THERE
HAS BEEN SOME VARIABILITY IN VSBYS DUE TO THE FOG MOVEMENT.
EXPECT TEMPO GROUPS OF 1/4 MILE AT TIMES AT UNV AND AOO...AND MVFR
RESTRICTIONS DUE TO THE PATCHY NATURE OF THE FORMING FOG THROUGH
THE FIRST HALF OF THE OVERNIGHT HOURS. AS THE FOG/MIST BECOMES
ENTRENCHED BETWEEN 06Z TO 09Z...VSBYS WILL DECREASE AND REMAIN IFR
AND LOWER.
MAINLY VFR CONDS WILL PREVAIL AT JST AND BFD...DUE TO
THE DRY NW FLOW ALOFT. FOG/MIST THROUGH THE LOWER SUSQ IS AN
INTERESTING CONUNDRUM. THOUGH SOME HIGH CLOUDS PERSIST...CALMING
WINDS...DEWPOINT DEPRESSIONS OF CURRENT 4 DEGREES OR LESS...SHOULD
ALLOW FOR FOR DENSE FOG OVERNIGHT. EXPECT PERIODS OF IFR VSBYS AND
LOWER ESPECIALLY NEAR SUNRISE. THE FOG WILL SLOWLY LIFT/DISSIPATE
TOMORROW MORNING...THOUGH QUICKER THAN IT DID ON SUNDAY. SO
EXPECT VFR TO RETURN BY 15Z MON AT ALL SITES.
A MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS
THE AREA MONDAY...POTENTIALLY BRINGING RESTRICTIONS TO KJST LATER
MONDAY AND SPREADING INTO MAINLY THE SOUTHERN HALF OF THE STATE
MON NIGHT.
OUTLOOK...
MON-MON NIGHT...CHANCE FOR MVFR CONDITIONS IN -SHRA ACROSS THE
SOUTHERN HALF OF PENN.
TUE...NO SIG WX EXPECTED.
TUE NIGHT-WED NIGHT...CHANCE FOR MVFR CIGS.
THU-FRI...MVFR POSS NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR PAZ012-
017>019-025>028-034>036-041-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...MARTIN
NEAR TERM...FITZGERALD
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...FITZGERALD/MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1147 PM EST SUN DEC 6 2015
.SYNOPSIS...
AN UPPER LEVEL LOW DROPPING SE FROM THE OHIO VLY MAY BRING
A FEW SHOWERS TO SOUTHERN PA ON MONDAY. ANOTHER UPPER LEVEL
LOW MOVING ACROSS THE GREAT LAKES ON WED MAY BRING A FEW MORE
SHOWERS TO THE AREA LATER WED INTO THU. OTHERWISE HIGH PRESSURE
OVER THE SE STATES WILL KEEP DRY AND MILD CONDITIONS ACROSS
THE KEYSTONE STATE THIS WEEK. HIGH TEMPERATURES WILL AVERAGE
WELL ABOVE NORMAL FOR EARLY DEC.
&&
.NEAR TERM /UNTIL 10 AM MONDAY MORNING/...
10 PM UPDATE...
FOG IS FORMING AS FCST. IT IS DENSE IN THE ADVY AREA ALREADY AND
MAY EXPAND. BUT WILL WAIT A BIT LONGER TO DECIDE IF THE NOT-
ADVISED AREAS WILL NEED ONE AS WELL. TEMPS ARE ABOVE FREEZING IN
THE LAURELS AND IN KBFD.
UPDATE: I DUG DEEPER AND DISCOVERED THAT CTP CAN INDEED ISSUE A
FREEZING FOG ADVY. HOWEVER...THE THREAT OF DENSE FOG IS CORRECT
AND I AM HITTING THE ICE THREAT HARD IN THE TEXT AND SOCIAL MEDIA.
TO KEEP CONFUSION TO A MINIMUM...WILL JUST KEEP IT AS A DENSE FOG
ADVY. IF THIS RECURRS TOMORROW NIGHT...WILL ASSESS THE THREATS
AND APPROPRIATE PRODUCTS/WORDING THEN.
7 PM UPDATE...
TWO CALLS NOW THAT INDICATE DENSE FOG IN LOW LYING AREAS OF HAPPY
VALLEY. AOO AND A FEW OTHER SITES HAVE ALSO SHOWN HINTS AT GOING
LOW ON THE VISBY. AT THIS POINT...ONLY KFIG IS AT 1/4SM...NONE ARE
BELOW THAT. HOWEVER...DEWPOINT DEPRESSIONS ARE ONLY 1-2F AT MANY
SITES. WILL GO AHEAD AND ISSUE A DENSE FOG ADVY FOR THE CENTRAL
COUNTIES...STARTING SMALL. CONFIDENCE IS STILL LOWER THAN
NECESSARY - BUT ALMOST THERE - THAT WE WOULD NEED THE SAME OVER
THE AREAS WHICH DRIED OUT BETTER/LONGER DURING THE DAY TODAY. WILL
START WITH THE PLACES THAT DID NOT CLEAR OR CLEARED FOR ONLY A
SHORT TIME.
5 PM UPDATE...
FOG AND STRATUS NEVER LEFT THE MID SUSQ AND LIKELY WILL NOT GO
AWAY IN THE NEXT 18HRS. VISBY OUT THE WINDOW AT LAST DAYLIGHT IS
ABOUT 3SM IN A THICK HAZE AND KUNV ONLY 1-2SM AWAY IS ONLY 1/8SM -
ACTUAL OBSERVER AT TOWER. FOG IS STARTING TO SHOW UP AGAIN IN THE
OBS AT MANY OF THE SITES WHICH DID CLEAR UP EARLIER TODAY.
BUT...LOOKS LIKE IT IS ALMOST CERTAIN THAT IT WILL RE-ESTABLISH
TONIGHT. THE HIGH CLOUDS SHOULD NOT SERIOUSLY AFFECT THE
BLYR...BUT THAT IS THE ONLY FACTOR IN THE MIX WHICH COULD BUST A
FOGGY FORECAST - IF IT STAYS MILDER. MAY NEED TO HOIST THE DENSE
FOG ADVY IN JUST A SHORT WHILE. WAITING FOR JUST A FEW MORE OBS TO
BE A LITTLE MORE CERTAIN. AGAIN...THE THREAT WILL PROBABLY BE A
COMBINATION OF REDUCED VISBY AND THE PRESENCE OF FREEZING FOG AND
POSSIBILITY OF AN ICY COATING. NOT REALLY A PRODUCT AVAILABLE TO
CENTRAL PA TO COVER THIS. SO WE CAN BASICALLY TRY TWO ROUTES-
EITHER USE A WINTER WX ADVY OR...LIKE WE HAD EARLIER...THE DENSE
FOG ADVY WITH LOTS OF ICY WORDS IN IT. TO KEEP IT CONSISTENT AND
ACCOUNT FOR THE FACT THAT THE ROADS MAY NOT BECOME ICY
EVERYWHERE...A DENSE FOG ADVY IS PROBABLY THE ROUTE TO CHOOSE
SHOULD WE NEED IT AGAIN.
PREV...
EXTREMELY STUBBORN FOG CONTINUES TO SLOWLY LIFT AND DISSIPATE OVER
THE CENTRAL MOUNTAIN VALLEYS EARLY THIS AFTERNOON. WARM ADVECTION
OVER THE COLD VALLEYS WHICH RADIATED EFFICIENTLY OVERNIGHT LED TO
SOME OF THE MOST PERSISTENT ICE FOG I`VE SEEN IN CENTRAL PA IN THE
PAST 15 YEARS. WHERE IT REMAINED FOGGY...TEMPERATURES REMAINED
BELOW FREEZING THIS MORNING...WHILE CLEAR AREAS WARMED THROUGH THE
40S AND IN SOME CASES INTO THE LOWER 50S (SOUTH CENTRAL
MOUNTAINS).
AS THE UPPER RIDGE AXIS BREAKS DOWN/ SWINGS EAST OF THE REGION
LATE TODAY AND TONIGHT...THIN CIRRUS WILL CONTINUE TO OVERSPREAD
THE EASTERN HALF OF CENTRAL PA...AS IT HAS OVER THE WEST. SFC HIGH
WEAKENS AND SHIFTS EAST OF PA TONIGHT...BUT IT REMAINS FAVORABLE
FOR PATCHY LATE NIGHT VALLEY FOG. MINS WILL BE MOSTLY IN THE MID
TO UPPER 20S ONCE AGAIN.
&&
.SHORT TERM /10 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
MOISTURE CHALLENGED UPPER TROF CRASHING INTO AND DISPLACING THE
EAST COAST UPPER RIDGE WILL MOVE OVER WESTERN AND CENTRAL PA ON
MONDAY...BRINGING CONSIDERABLE CLOUDINESS BUT LITTLE ELSE IN THE
WAY OF SENSIBLE WEATHER AFTER ANOTHER ROUND OF MORNING VALLEY FOG.
THINK THE ONLY AREA TO SEE SHOWERS FROM THIS SYSTEM WILL BE THE
LAUREL HIGHLANDS...AS BOUNDARY LAYER IS JUST TOO DRY TO SUPPORT
MUCH PRECIPITATION FARTHER EAST. CLOUDS WILL BE THICKEST OVER THE
LAUREL HIGHLANDS AS WELL...WITH MOSTLY CLOUDY SKIES SEEN THERE...
WHILE THE REMAINDER OF CENTRAL PA RANGES FROM P/S TO M/S. HIGHS
WILL BE FAIRLY UNIFORM...RANGING FROM THE UPPER 40S TO THE LOWER
50S.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THE MAIN FORECAST STORY FOR THE EXTENDED PERIOD IS THE CONTINUED
MILD TEMPERATURES...AS ZONAL FLOW FLOODS THE CONUS WITH PACIFIC
AIR. NAEFS AND ECENS OUTPUT SHOWING A SERIES OF SFC LOWS TRACKING
NORTHWARD THRU THE GRT LKS LATE NEXT WEEK...AS ANOMALOUS UPPER
RIDGE BUILDS ALONG THE E COAST. HAVE INCLUDED A CHC OF SHRA ASSOC
WITH SHORTWAVE LIFTING UP THE OHIO VALLEY LATE WED/EARLY THU.
OTHERWISE...THE EXTENDED FCST APPEARS DRY AND INCREASINGLY WARM
BENEATH BUILDING RIDGE.
GEFS PLUME DATA AND ECEME MOS SUPPORT MIN TEMPS ABOVE FREEZING
ACROSS THE ENTIRE CWA THU-SAT AND MAX TEMPS AT LEAST 15F ABV
NORMAL.
MAIN CHANGE WAS TO EDGE TEMPS UP A LITTLE.
ALSO MORE FOG COULD FORM TUESDAY MORNING...AS SKIES CLEAR.
THUS I ADDED PATCHY FOG.
ICE FOG ON A LOT OF OBJECTS EARLY TODAY.
A BIG CHANGE FROM THE LAST 2 WINTERS...ENJOY THE GOOD WEATHER
WHILE IT LAST.
FOR NEXT WEEKEND...STILL MILD...BUT SOME CHC OF SHOWERS BY
SUNDAY. WENT WITH CHC POPS FOR NOW.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
THE BIGGEST FORECAST QUESTION OVERNIGHT IS FOG FORMATION. CURRENT
HRRR AND RAP RUNS DECREASE THE FOG THROUGH MOST OF THE CENTRAL PA
BY 09Z...HOWEVER GIVEN THE LOW DEWPOINT DEPRESSIONS...CALM WINDS
AN STRONG INVERSION EXPECT CENTRAL TAF SITES AOO...UNV...IPT TO
SEE IFR AND LOWER CIGS AND VSBYS OVERNIGHT UNTIL MORNING. THERE
HAS BEEN SOME VARIABILITY IN VSBYS DUE TO THE FOG MOVEMENT.
EXPECT TEMPO GROUPS OF 1/4 MILE AT TIMES AT UNV AND AOO...AND MVFR
RESTRICTIONS DUE TO THE PATCHY NATURE OF THE FORMING FOG THROUGH
THE FIRST HALF OF THE OVERNIGHT HOURS. AS THE FOG/MIST BECOMES
ENTRENCHED BETWEEN 06Z TO 09Z...VSBYS WILL DECREASE AND REMAIN IFR
AND LOWER.
MAINLY VFR CONDS WILL PREVAIL AT JST AND BFD...DUE TO
THE DRY NW FLOW ALOFT. FOG/MIST THROUGH THE LOWER SUSQ IS AN
INTERESTING CONUNDRUM. THOUGH SOME HIGH CLOUDS PERSIST...CALMING
WINDS...DEWPOINT DEPRESSIONS OF CURRENT 4 DEGREES OR LESS...SHOULD
ALLOW FOR FOR DENSE FOG OVERNIGHT. EXPECT PERIODS OF IFR VSBYS AND
LOWER ESPECIALLY NEAR SUNRISE. THE FOG WILL SLOWLY LIFT/DISSIPATE
TOMORROW MORNING...THOUGH QUICKER THAN IT DID ON SUNDAY. SO
EXPECT VFR TO RETURN BY 15Z MON AT ALL SITES.
A MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS
THE AREA MONDAY...POTENTIALLY BRINGING RESTRICTIONS TO KJST LATER
MONDAY AND SPREADING INTO MAINLY THE SOUTHERN HALF OF THE STATE
MON NIGHT.
OUTLOOK...
MON-MON NIGHT...CHANCE FOR MVFR CONDITIONS IN -SHRA ACROSS THE
SOUTHERN HALF OF PENN.
TUE...NO SIG WX EXPECTED.
TUE NIGHT-WED NIGHT...CHANCE FOR MVFR CIGS.
THU-FRI...MVFR POSS NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM EST MONDAY FOR PAZ012-017>019-
025>028-034>036-041-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...MARTIN
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR
LONG TERM...FITZGERALD/MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
400 AM CST MON DEC 7 2015
.SHORT TERM (TODAY THROUGH TUESDAY)...
ONE LAST COOL MORNING TODAY WITH A WARMING TREND BEGINNING AND
LASTING INTO AT LEAST FRIDAY. IT WILL BE A STRAIGHT TEMPERATURE
FORECAST AS NO PRECIPITATION IS EXPECTED IN THE SHORT AND MOSTLY
LONG TERM PERIODS.
WATER VAPOR AND RAP ANALYSIS DEPICTS AN EXITING TROUGH AXIS ACROSS
THE MID-MISSISSIPPI RIVER VALLEY WITH MID-LVL NORTHWEST FLOW OVER
TOP SURFACE HIGH PRESSURE CENTERED OVER THE LONE STATE STATE.
CLEAR SKIES ARE EXPECTED TODAY AND TOMORROW THAT...ALONG WITH A
SLOWLY MODIFYING AIRMASS...WITH PROMOTE A WARMING TREND THAT WILL
CONTINUE INTO MID AND LATE WEEK. MAX HIGHS TODAY SHOULD BE QUITE
SIMILAR TO YESTERDAY TO 1F DEGREE COOLER GIVEN THE SLIGHTLY LOWER
MIXING HEIGHTS. THE RESULTANT TEMPERATURES SUPPORTED BY THE
GFS/NAM SOUNDINGS FALL MUCH MORE IN LINE WITH THE MAVMOS VALUES
WITH SOME SLIGHT +1F DEGREE TWEAKS MADE GIVEN PAST TRENDS. MIXING
HEIGHTS WILL INCREASE TUESDAY WITH WARMER 925MB HEIGHTS THAT WILL
SUPPORT AN ADDITIONAL 2-4F DEGREES OVER TODAY`S HIGHS. MORNING
LOWS WILL NOT BE AS COOL TUESDAY VS. THIS MORNING AS WEAK SOUTH
WINDS SLOWLY INCREASE DEWPOINT VALUES.
&&
.LONG TERM (WEDNESDAY THROUGH SUNDAY)...
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED MID TO LATE WEEK AS
READINGS WILL LIKELY REACH INTO THE UPPER 70S AND LOW TO EVEN MID
80S ACROSS THE REGION. RAIN CHANCES WILL INCREASE AHEAD OF A FRONT
THAT COULD MOVE THROUGH LATE SATURDAY INTO SUNDAY.
A SUBTROPICAL SURFACE HIGH WILL BECOME ESTABLISHED OVER THE GULF
AND EXTEND TOWARDS SOUTH-CENTRAL TEXAS THROUGH MID TO LATE-WEEK.
THIS FEATURE...AND WITH THE MAIN JET STREAM WELL NORTH...WILL
CONTINUE TO FOSTER LOW-LVL WARMING WITH SOUTHWEST AND WEST FLOW IN
THE 925-700MB LAYER. THIS PATTERN IS ONE THAT ALLOWS HIGHER
TEMPERATURES TO BE ACHIEVED...ESPECIALLY GIVEN THE ADVERTISED WELL
MIXED PBL TRANSLATING THE COMPRESSIONALLY WARMED AIR DOWN TO THE
SURFACE. READINGS BY THURSDAY AND ESPECIALLY INTO FRIDAY WILL BE
7-15F DEGREES ABOVE NORMAL WITH RIO GRANDE LOCATIONS PUSHING INTO
THE MID TO UPPER 80S. KSAT WILL APPROACH 80F THURSDAY AND LIKELY
SURPASS 80F FRIDAY WITH KAUS COMING QUITE CLOSE AS WELL. FRIDAY
WILL ALSO BE QUITE BREEZY /20MPH WINDS & GUSTS TO 30MPH/ AHEAD OF
A DEVELOPING SYSTEM FARTHER WEST OVER THE FOUR CORNER REGION. BOTH
ECMWF AND GFS LONGER RANGE MOS VALUES ARE IN GOOD AGREEMENT OF
THESE VALUES WITH BUFR SOUNDINGS CONFIRMING THE STRONG LIKELIHOOD
OF WELL ABOVE NORMAL TEMPERATURES. MORNINGS LOWS WILL SLOWLY COME
UP AS WELL AS DEWPOINTS SLOWLY CLIMB THROUGH SATURDAY.
BY LATE WEEK AND OVER THE WEEKEND...A STRONG H5 TROUGH WILL DIG
ACROSS THE WESTERN BASIN. GFS AND EC DIVERGE ON THIS SYSTEM`S
PROGRESSIVENESS. OPERATIONAL GFS IS QUICKER TO MOVE IT THROUGH
VS. ECMWF THAT LAGS THE ENERGY BACK WEST. GFS ENSEMBLES SUGGEST A
SLIGHTLY LESS PROGRESSIVE SYSTEM VS. THE OPERATIONAL GFS RUN AND
HAVE WEIGHTED SATURDAY/SUNDAY TEMPS AND POPS MORE TOWARDS THE
ENSEMBLE MEAN. A COLD FRONT SHOULD MOVE THROUGH SOMETIME LATE
SATURDAY OR LATE SUNDAY. WILL NEED TO FINE TUNE THIS SECTION AS
SOLUTIONS CONVERGE ON BETTER SYSTEM TIMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 70 46 73 49 76 / 0 0 0 0 -
AUSTIN BERGSTROM INTL AIRPORT 69 42 73 47 75 / 0 0 0 0 -
NEW BRAUNFELS MUNI AIRPORT 69 44 74 49 76 / 0 0 0 0 -
BURNET MUNI AIRPORT 67 43 73 46 74 / 0 0 0 0 0
DEL RIO INTL AIRPORT 71 44 74 47 76 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 66 42 74 47 74 / 0 0 0 0 -
HONDO MUNI AIRPORT 69 43 74 47 76 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 67 44 73 48 75 / 0 0 0 0 -
LA GRANGE - FAYETTE REGIONAL 68 46 73 50 75 / 0 0 0 0 -
SAN ANTONIO INTL AIRPORT 71 46 75 50 75 / 0 0 0 0 0
STINSON MUNI AIRPORT 70 46 75 50 76 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...17
SYNOPTIC/GRIDS...ALLEN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
435 AM EST MON DEC 7 2015
.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM, WILL CROSS THE OHIO VALLEY TODAY.
HIGH PRESSURE WILL THEN BUILD IN BEHIND THIS SYSTEM FOR TONIGHT
AND TUESDAY. LOW PRESSURE WILL DEVELOP OFF THE CAROLINA COAST
TODAY AND DEEPEN AS IT MOVES NORTHEAST INTO THE WESTERN ATLANTIC.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST MONDAY...
WATCHING TWO AREAS OF PRECIPITATION TODAY. THE FIRST IS WITH AN
UPPER LOW THAT WAS TRACKING EAST INTO OHIO AT 4AM AND THE SECOND
WITH A DEVELOPING SURFACE LOW OFF THE CAROLINA COAST. WIDELY
SCATTERED RAIN HAD DEVELOPED ALONG ANS WEST OF A BLUEFIELD TO
BRISTOL LINE. TEMPERATURES WERE SLOWLY WARMING ON THE WEST SIDE OF
THE MOUNTAINS WITH DEW POINTS RISING INTO THE LOWER TO MIDDLE 30S.
THERE WERE A FEW MESONET SITES IN MERCER...TAZEWELL AND SMYTH
COUNTIES WHICH REPORTED TEMPERATURES BELOW JUST BELOW FREEZING.
THESE TEMPERATURES WILL RISE ABOVE FREEZING BY 9AM... IF THERE IS
ANY RAIN BEFORE THEN...A LIGHT GLAZE OF ICE ON ELEVATED SURFACES
WILL BE POSSIBLE. HRRR SHOWED THIS PRECIPITATION DISSIPATING AS IT
MOVED EAST THIS MORNING.
A LARGER AREA OF SHOWERS WAS CLOSER TO THE UPPER LOW AND WILL REACH
WESTERN SECTIONS OF THE COUNTY WARNING AREA AFTER NOON AND MOVE EAST
ACROSS THE FORECAST AREA BY 03Z/10PM. CLOUDS WILL SPREAD INTO THE
AREA A COUPLE HOURS AHEAD OF THE ARRIVAL OF THE SHOWERS. THE BUFKIT
FORECAST SHOWED SOME GOOD MID LEVEL LAPSE RATES AS THE COLD POOL AT
500 MB ASSOCIATED WITH THE UPPER LOW CROSSES THE REGION. MODELS HAVE
THE UPPER TROF AND DEEP MOISTURE EAST OF THE FORECAST AREA BY
MIDNIGHT. EXPECTING A LAYER OF SHALLOW LOW CLOUDS IN THE WESTERN
UPSLOPE AREAS OF SOUTHEAST WEST VIRGINIA OVERNIGHT. RAIN AND CLOUD
COVER WITH THE SOUTHEAST LOW WAS EXPECTED TO STAY SOUTHEAST OF THE
FORECAST AREA TODAY.
COUNTIES IN THE VIRGINIA AND NORTH CAROLINA PIEDMONT WILL HAVE THE
MOST SUNSHINE TODAY AND THEREFORE THE WARMEST MAXIMUM TEMPERATURES.
STAYED CLOSE TO LOCAL WRF AND THE LATEST RUNS OF GRIDDED LAMP
GUIDANCE FOR MAXIMUM TEMPERATURES THIS AFTERNOON. MODELS HAD MORE OF
A SPREAD WITH LOWS OVERNIGHT IN THE MOUNTAINS. TRENDED TOWARD COOLER
MAV NUMBERS FOR MINIMUM TEMPERATURES.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EST MONDAY...
WEAK HIGH PRESSURE WILL BE THE CONTROLLING FEATURE OF OUR WEATHER
PATTERN ON TUESDAY...WITH THE AXIS OF THE HIGH DRIFTING OFF THE
COAST LATE TUESDAY NIGHT AS OUR NEXT COLD FRONT APPROACHES FROM THE
MIDWEST REGION. WINDS WILL SHIFT SOUTHERLY AS THE HIGH DRIFTS EAST
WHICH...COMBINED WITH ABUNDANT SUNSHINE...WILL HELP PUSH AFTERNOON
TEMPERATURES INTO THE UPPER 40S/LOW 50S ACROSS THE MOUNTAINS...AND
INTO THE MID/UPPER 50S ACROSS THE PIEDMONT. LOW TEMPERATURES FOR
TUESDAY NIGHT WILL BE DEPENDENT ON ELEVATION...WITH THE RIDGES
HOLDING WARMER IN THE SOUTHWESTERLY WINDFLOW OFF THE SURFACE...WHILE
THE LOWER ELEVATIONS WILL DECOUPLE AND EXPERIENCE RADIATIONAL
COOLING. BELIEVE SOME OF THE HIGHER RIDGES WILL REMAIN IN THE
LOW/MID 40S OVERNIGHT...WHILE TEMPERATURES WILL FALL INTO THE UPPER
20S TO MID 30S IN LOWER ELEVATIONS.
CLOUDS WILL INCREASE DURING EARLY WEDNESDAY MORNING AS THE COLD
FRONT APPROACHES...WITH A FEW SHOWERS ENTERING THE AREA JUST BEFORE
SUNSET. SOUTHWESTERLY FLOW AHEAD OF THE FRONT WILL MAINTAIN MILD
TEMPERATURES...WITH HIGHS REACHING INTO THE 50S AREAWIDE. SHOWER
ACTIVITY WILL INCREASE ACROSS THE WESTERN RIDGES AFTER SUNSET...BUT
DO NOT EXPECT THIS ACTIVITY TO MAKE MUCH PROGRESS FURTHER EAST AS
WINDS SHIFT WEST NORTHWESTERLY WITH FRONTAL PASSAGE. DOWNSLOPE
WINDFLOW WILL CAUSE THE SHOWERS TO BREAK UP BY THE TIME THEY REACH
THE BLUE RIDGE. ONLY MODEST RAINFALL AMOUNTS ARE EXPECTED...PERHAPS
AROUND A TENTH OF AN INCH IN PORTIONS OF SOUTHEAST WEST VIRGINIA.
MAY SEE A FEW UPSLOPE SHOWERS LINGER ALONG THE WESTERN RIDGES
WEDNESDAY NIGHT...BUT BELIEVE THIS ACTIVITY WILL BE GONE BY SUNRISE
THURSDAY...WITH DRY CONDITIONS EXPECTED FOR THE REMAINDER OF THE
DAY. IT WONT TAKE LONG FOR WINDS TO SHIFT SOUTHWESTERLY AGAIN AS YET
ANOTHER UPPER LEVEL DISTURBANCE SETS UP OVER THE GREAT LAKES. AS
SUCH...MILD TEMPERATURES WILL CONTINUE.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 240 AM EST MONDAY...
THE SYNOPTIC WEATHER PATTERN THROUGH SATURDAY ACROSS THE CENTRAL AND
EASTERN PARTS OF THE COUNTRY TRANSITIONS INTO A NEARLY ZONAL PATTERN
WITH THE POTENTIAL FOR ONE WEAK DISTURBANCE CROSSING THE AREA ON
FRIDAY. THIS WILL ALLOW FOR A GENERAL TREND TOWARDS TEMPERATURES
EVEN HIGHER THAN NORMAL...BUT AS MUCH AS PERHAPS 15 DEGREES.
ISOLATED SHOWERS WILL BE POSSIBLE ACROSS PORTIONS OF MAINLY
SOUTHEAST WEST VIRGINIA ON FRIDAY. OTHERWISE THROUGH SATURDAY...
EXPECT PRECIPITATION FREE CONDITIONS ACROSS THE AREA.
THE FORECAST SPECIFICS AT THE END OF THE FORECAST CYCLE GET A BIT
MORE UNCERTAIN. WHILE GUIDANCE BETWEEN THE GFS AND ECMWF AGREE THERE
WILL BE A STRONG COLD FRONT PASSAGE EARLY NEXT WEEK...THEY DIFFER
REGARDING THE TIMING. THE ECMWF IS A LITTLE QUICKER IN BRINGING THE
FRONT THROUGH THE REGION DURING THE DAY MONDAY...WITH THE SLOWER GFS
ABOUT 6 TO 12 HOURS LATER. HOWEVER...BOTH MODELS ARE WITHIN SIX
HOURS IN REGARDS TO THE ONSET OF SOME PRE-FRONTAL RAIN SHOWERS
STARTING LATE SATURDAY NIGHT...WITH A CONTINUATION OF SHOWERS AHEAD
OF THE FRONT ON SUNDAY. OUR FORECAST WILL REFLECT THIS SCENARIO
SATURDAY NIGHT INTO SUNDAY. TEMPERATURES WILL REMAIN ON THE VERY
MILD SIDE...BUT PERHAPS A LITTLE COOLER GIVEN INCREASING CLOUD COVER
AND CHANCES OF RAIN SHOWERS.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
AS OF 1000 PM EST SUNDAY...
HIGH CONFIDENCE IN VFR/LIGHT WIND CONDITIONS OVERNIGHT FOR ALL
TAF SITES...FOLLOWED BY INCREASING CHANCES FOR BELOW VFR FOR THE
DAYLIGHT HOURS MONDAY.
SATELLITE IMAGES CURRENTLY SHOW JUST SOME HIGH CIRRUS OVER THE
AREA AND IT SHOULD REMAIN THIS WAY FOR MOST OF THE OVERNIGHT.
REGIONAL SOUNDINGS ARE BEGINNING TO SHOW A RETURN OF MOISTURE
BETWEEN 700-900 MB...THUS WOULD EXPECT DEVELOPMENT OF A CLOUD
LAYER BETWEEN 3-7KFT AGL LATER TONIGHT AND EARLY MONDAY.
A VIGOROUS BUT MOISTURE STARVED CLOSED LOW WITH A WEAK SURFACE
REFLECTION WILL MOVE INTO THE REGION FROM THE WEST LATE TONIGHT.
THIS WILL/SHOULD RESULT IN THE DEVELOPMENT OF A LAYER OF LOW LEVEL
CLOUDINESS PRIOR TO DAYBREAK MONDAY WITH INCREASING CHANCE FOR
PRECIPITATION AS WE PROGRESS THROUGH THE DAY MONDAY. HAVE
MAINTAINED A DRY FORECAST AT ALL TAF SITES PRIOR TO 12Z/7AM
MONDAY.
AS THE SYSTEM MOVES THROUGH THE REGION IT WILL BECOME QUITE
FRAGMENTED AS IT TRANSFERS ENERGY TO A NEW LOW DEVELOPING OFF THE
COAST. THIS SHOULD ALLOW SITES FROM THE BLUE RIDGE EASTWARD TO
MAINTAIN VFR CONDITIONS IN LIMITED SHOWER ACTIVITY WHILE KLWB/KBCB
AND ESPECIALLY KBLF EXPERIENCE MVFR/IFR CONDITIONS WITH SOME WEAK
UPSLOPE AS WINDS BECOME MORE NWLY.
.EXTENDED AVIATION DISCUSSION...
WEAK HIGH PRESSURE FOLLOWS THIS SYSTEM WITH A RETURN TO VFR ON
TUESDAY. ANOTHER WEAK UPPER LEVEL DISTURBANCE MAY BRING SOME MVFR
CIGS AND ISOLATED SHOWERS TO THE WESTERN SLOPES LATER
WEDNESDAY...OTHERWISE CONTINUED VFR INTO THURSDAY.
&&
.EQUIPMENT...
AS OF 300 AM EST SUNDAY...
T1 LINE IS DOWN PREVENTING DISSEMINATION OF THE BLUEFIELD ASOS
OBSERVATION. THE FAA HAS OPENED A TROUBLE TICKET AND IS WORKING ON
THE ISSUE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...DS
AVIATION...MBS/PM
EQUIPMENT...JH
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
528 AM EST MON DEC 7 2015
.SYNOPSIS...
ISSUED AT 421 AM EST MON DEC 7 2015
WIDESPREAD FOG WILL CONTINUE TO DEVELOP OVER MUCH OF NORTHERN
INDIANA AND FAR SOUTHWEST LOWER MICHIGAN AND EXTEND INTO NORTHWEST
OHIO. EARLY MORNING TEMPERATURES WILL RANGE FROM THE UPPER 20S TO
UPPER 30S WHERE CLOUDS LINGERED OVERNIGHT. THE NEXT CHANCE OF RAIN
WILL ARRIVE LATE TUESDAY INTO WEDNESDAY.
&&
.UPDATE...
ISSUED AT 516 AM EST MON DEC 7 2015
HAVE ADDED 6 COUNTIES TO THE DENSE FOG ADVISORY. SKIES HAVE
CLEARED OVER NEARLY ALL OF NORTHERN INDIANA AND NORTHWEST OHIO.
DENSE FOG WAS DEVELOPING SOUTH AND EAST AND SHOULD DEVELOP/SPREAD
INTO AREAS SOUTHWEST AND WEST OF FORT WAYNE INCLUDING WABASH AND
COLUMBIA CITY. SOME LOW CLOUDS HAVE MOVED INTO LAPORTE AND BERRIEN
COUNTIES AND MAY ACTUALLY HELP FOG TO LIFT A LITTLE. AT THIS
TIME...WE ARE WATCHING COUNTIES ON THE EDGE OF THE ADVISORY
INCLUDING GRANT...HUNTINGTON AND ALLEN INDIANA FOR POSSIBLE
EXPANDING OF THE DENSE FOG ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 416 AM EST MON DEC 7 2015
THE COMBINATION OF RADIATION FOG AND ADVECTION FOG WAS MAKING THE
FORECAST VERY CHALLENGING EARLY THIS MORNING. SKIES HAD CLEARED OVER
FAR SOUTHWEST LOWER MICHIGAN AND NORTHERN INDIANA WHERE RADIATIONAL
COOLING HAD ALLOWED FOG TO FORM. THE FOG WAS BECOMING MORE
WIDESPREAD AND BECOMING LOCALLY DENSE WITH VISIBILITIES AROUND OR
UNDER A QUARTER OF MILE. ADDITIONAL LOW CLOUDS AND SOME FOG WAS
SPREADING SOUTHEAST OVER LAKE MICHIGAN AND SHOULD SPREAD INTO FAR
SOUTHWEST LOWER MICHIGAN AND NORTHWEST INDIANA EARLY THIS MORNING.
HAVE ISSUED A DENSE FOG ADVISORY FOR ALL OF FAR SOUTHWEST LOWER
MICHIGAN AND NORTHWEST INDIANA...INTO THE NORTHERN PORTION OF
NORTHWEST OHIO. THE TEMPERATURE IN SOME SPOTS WILL BE COLD ENOUGH
FOR THE FOG TO BECOME FREEZING AND DEPOSIT A LIGHT FROST OR VERY
LIGHT ICE LAYER. GIVEN LIMITED INSOLATION AND VERY LIGHT FLOW
ALOFT...THE DENSE FOG WILL LIKELY PERSIST THROUGH MOST OF THE
MORNING. OTHERWISE...CONDITIONS WILL IMPROVE THIS AFTERNOON WITH
HIGHS ABOVE NORMAL OVER MOST AREAS.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 416 AM EST MON DEC 7 2015
FOCUS IN LONG TERM CONTINUES TO BE ON MID LEVEL AMPLIFICATION
THROUGH THE PERIOD AND POSSIBLE RECORD SETTING TEMPERATURES BY THE
WEEKEND ALONG WITH MODERATE TO HEAVY RAINFALL POTENTIAL.
INITIALLY...WILL BE CAUTIOUSLY OPTIMISTIC THAT WIDESPREAD DENSE FOG
WILL NOT BE AN ISSUE TO START THE PERIOD TUESDAY MORNING. SFC
GRADIENT SHOULD BE INCREASING AS HIGH PRESSURE SLIDES EAST AND NEXT
SHORT WAVE AND SFC TROUGH APPROACH FROM WEST. SOUNDINGS AND CROSS
SECTIONS DO SHOW RESIDUAL MOISTURE SO MOSTLY CLOUDY TO START THE
DAY. MIXING MAY ALLOW FOR PARTLY CLOUDY SKIES MID DAY BUT WILL
QUICKLY GO BACK TO CLOUDY AS NEXT PACIFIC SHORT WAVE MOVES IN
TUESDAY NIGHT INTO WEDNESDAY. IT STILL APPEARS ENOUGH MOISTURE AND
WEAK LIFT TO SUPPORT LOW PCPN CHANCES FOR LIGHT SHOWERS WITH DECENT
DPVA AND MODEST MOISTURE PROFILES. HIGHS WILL BE IN THE 40S DURING
THIS PERIOD WITH LOWS IN THE UPPER 30S TO EVEN LOWER 40S WITH
CLOUDS.
THIS MID WEEK SYSTEM MARKS THE NOSE OF MUCH STRONGER JET ENERGY
WHICH ORIGINATED OVER EAST ASIA LAST WEEK AND HAS FINALLY MADE ITS
WAY OVER THE WESTERN CONUS. AN IMPRESSIVE 120-140 KT JET CORE
STRETCHES OVER THE ENTIRE PACIFIC WITH 160+ KT EMBEDDED STREAKS PER
MODELS. THIS ENERGY WILL CONTINUOUSLY DRIVE INLAND OVER WESTERN
CONUS THIS WEEK...PROGRESSIVELY CARVING OUT A DEEP TROUGH IN THE
SOUTHWEST. AS A RESULT...HEIGHTS WILL BUILD OVER THE MIDWEST AND
STRENGTHENING LOW LEVEL JET WILL PUMP VERY WARM AND MOIST AIR INTO
THE REGION BY LATE WEEK AND SETTING THE STAGE FOR POSSIBLE HEAVY
RAINFALL. STILL A LOT OF UNCERTAINTY AND RUN TO RUN INCONSISTENCIES
BETWEEN MODELS FOR MUCH ADDED FORECAST DETAILS.
HOWEVER...PATTERN IS SUPPORTED BY MOST MODELS AND FITS THE LARGER EL
NINO PATTERN.
TEMPERATURES WILL REMAIN MILD THIS WEEK AND LOOK VERY WARM BY THE
WEEKEND WITH GUIDANCE ALREADY POINTING TO POTENTIAL RECORD HIGHS IN
THE 60S TO EVEN 70 IN OUR FAR SOUTH. CLOUDS AND RAIN WILL HAVE A LOT
TO DO WITH HOW WARM WE ACTUALLY GET BUT POTENTIAL IS CERTAINLY
THERE. ECMWF AND GFS ALSO DIFFER ON HOW ENERGY WILL EJECT OUT OF
SOUTHWEST AND IMPACT US LOCALLY. GFS CONTINUES TO SHOW A COUPLED JET
STRUCTURE BUT ECMWF BRINGS JET ENERGY OUT IN SEPARATED WAVES.
REGARDLESS...POPS IN HIGH CHANCE TO LIKELY CATEGORY WARRANTED. HIGH
PRECIPITABLE WATER VALUES OF 1-1.25 INCHES ALSO SHOWN BY GFS AND
WILL BE NEAR RECORD TERRITORY FOR MID DECEMBER SO THREAT FOR HEAVY
RAIN IS A POSSIBILITY. DETAILS AND TIMING WILL NEED TO BE SORTED OUT
WITH TIME AS MORE OF THIS JET CORE COMES ONSHORE AND GETS SAMPLED
BETTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 113 AM EST MON DEC 7 2015
HAVE MADE SIGNIFICANT CHANGES TO THE ONGOING TAFS WITH THE 06Z
ISSUANCE. SOME LIMITED CLEARING WITH VERY WEEK FLOW AT THE SURFACE
AND LOW LAYERS HAS ALREADY ALLOWED PATCHY DENSE FOG TO DEVELOP
OVER NORTHERN INDIANA BEFORE 06Z. THE FOG WAS MUCH MORE
WIDESPREAD OVER LOWER MICHIGAN AND TO A LESSER EXTENT NORTHEAST
ILLINOIS. MOST TEMP/DEW POINT SPREADS WERE 3 DEGREES OR LESS.
GIVEN THE LATEST OBSERVATIONS AND TRENDS AND GIVEN THE LATEST HIGH
RESOLUTION NCEP/WPC ESPECIALLY THE HRRR AND ARW...EXPECT THE FOG
TO DEVELOP AND BECOME DENSE BEFORE 12Z. GIVEN THE WEAK
FLOW...LIMITED INSOLATION THE FOG WILL BE VERY SLOW TO
LIFT...WITH LINGERING STRATUS LIKELY THIS AFTERNOON.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...DENSE FOG ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR
INZ003>009-012>017-020-022>024.
MI...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR MIZ077>081.
OH...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR OHZ001-002-
004-005.
LM...NONE.
&&
$$
UPDATE...SKIPPER
SYNOPSIS...AGD/SKIPPER
SHORT TERM...SKIPPER
LONG TERM...LASHLEY
AVIATION...SKIPPER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
633 AM EST MON DEC 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM EST MON DEC 7 2015
00Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW A ZONAL SPLIT FLOW
OF PACIFIC AIR OVER SRN CANADA AND THE CONUS. SHRTWV RDG AXIS IS
MOVING INTO THE WRN GREAT LKS EARLY THIS MRNG...WITH WEAK SFC HI
PRES RDG STRETCHING FM NW ONTARIO ACRS WRN UPR MI TO STRONGER HI
PRES CENTERED OVER THE SRN PLAINS. ALTHOUGH THE AIRMASS OVHD IS
DRY...WITH 00Z PWAT AS LO AS ABOUT 0.20 INCH AT MPX...LINGERING LLVL
MSTR SHOWN ON LOCAL 00Z RAOBS TRAPPED UNDER LO SUBSIDENCE INVRN IS
CAUSING QUITE A BIT OF LO CLD/FOG OVER MUCH OF THE CWA IN THE
PRESENCE OF NOCTURNAL COOLING. THE FOG/STRATUS IS MOST EXTENSIVE
OVER THE INTERIOR W HALF OF THE CWA...WITH MORE HIER BASED SC
LINGERING OVER THE E...WHERE THE 00Z GRB/APX RAOBS SHOW MORE MSTR
NEAR HIER INVRN BASE. AREAS NEAR LK SUP W OF MUNISING...EXCEPT FOR
THE KEWEENAW...AND OVER THE SCENTRAL E OF IRON MTN ARE MOCLR...
PROBABLY DUE TO LIGHT DOWNSLOPE W TO SW WINDS IN THESE AREAS. THE LO
CLD AND FOG STRETCH W THRU MUCH OF MN. MORE HI CLD IN COMMA TAIL OF
NRN BRANCH SHRTWV/SFC LO TRACKING INTO MANITBOA IS STREAMING E INTO
MN AS WELL...BUT VERY DRY AIRMASS SHOWN ON THE ABERDEEN SDAKOTA AND
BISMARCK RAOBS IS PREVENTING ANY PCPN OR EVEN LOWER CLDS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON FOG/LO CLD
TRENDS.
TODAY...AS SFC HI PRES RDG SHIFTS TO THE E AND LO PRES MOVES INTO NW
ONTARIO...EXPECT A STEADY S WIND TO DVLP OVER UPR MI. NAM H95 RH...
WHICH HAS A GOOD HANDLE ON THE AREA OF LO CLDS RIGHT NOW...HINTS THE
AREA OF LO CLDS WL EXPAND TO ALL BUT THE NW CWA...WHERE THE S WIND
DOWNSLOPES. WHILE DAYTIME HEATING WL LIKELY LIMIT FOG COVERAGE...LO
SUN ANGLE WL PROBABLY NOT BE SUFFICIENT TO MIX OUT THE LO CLD. SO
TENDED TOWARD MORE CLD COVER EXCEPT IN THOSE DOWNSLOPE AREAS NEAR LK
SUP FM MUNISING TO BARAGA/THE KEWEENAW...ONTONAGON AND IRONWOOD.
LOWERED FCST MAX TEMPS A COUPLE DEGREES WHERE THE LO CLD IS EXPECTED
TO BE MOST EXTENSIVE. EXPECT THE WARMEST TEMPS INTO THE 40S IN THE
DOWNSLOPE AREAS NEAR LK SUP.
TNGT...AXIS OF DEEP LYR QVECTOR CNVGC IN COMMA TAIL OF SHRTWV MOVING
TO THE ENE TOWARD HUDSON BAY IS FCST TO SHIFT W-E ACRS THE CWA.
ALTHOUGH THIS FORCING WL NOT BE SUFFICIENT TO SATURATE THE VERY DRY
MID LVLS...LIFTING OF THE SUBSIDENCE INVRN WL ALLOW FOR A GREATER
DEPTH OF LLVL MSTR. MANY OF THE HIER RES MODELS GENERATE SOME LGT
PCPN...ESPECIALLY IN AREAS DOWNWIND OF LK MI IN THE EXPECTED LLVL
SSW FLOW. WL RETAIN SOME LO CHC POPS FOR DRIZZLE AND ADD SOME FOG IN
THE FCST FOR THIS AREA. THE SOMEWHAT HIER INVRN BASE WL ALSO ALLOW
FOR MORE LO CLDS TO EXPAND EVEN INTO THE DOWNSLOPE AREAS NEAR LK
SUP. TEMPS WL RUN WELL ABOVE NORMAL...MAINLY IN THE 30S...WARMEST
DOWNWIND OF LK MI.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 310 AM EST MON DEC 7 2015
LONG TERM WILL SEE SEVERAL SHORTWAVES MAKING FOR A BUSIER
PATTERN...BUT AT THIS TIME PRECIP AMOUNTS LOOK TO BE MOSTLY
INSIGNIFICANT. MAY SEE SOME MORE SIGNIFICANT PRECIP NEXT
WEEKEND...BUT PREDICTABILITY IS QUITE LOW.
MAY SEE SOME LIGHT PRECIP OVER THE E ON TUE...MAINLY TUE
MORNING...AS A SHORTWAVE PASSES THROUGH. MODELS SHOW
ANOTHER...STRONGER...SHORTWAVE MOVING THROUGH THE REGION BETWEEN TUE
EVENING AND WED AFTERNOON. MODELS CONTINUE TO DISAGREE ON STRENGTH
OF THE SHORTWAVE...SO TIMING/COVERAGE/AMOUNTS OF PRECIP ARE
UNCERTAIN. COULD SEE SOME GREATER PRECIP AMOUNTS (GFS AND NAM
SHOWING UPWARDS OF ONLY 0.2 INCHES)...BUT MOST OF THAT SHOULD FALL
AS RAIN. COULD SEE SOME VERY MINOR MEASURABLE SNOW...BUT
INSIGNIFICANT REALLY.
PRECIP ASSOCIATED WITH NEXT SHORTWAVE LOOKS TO MOVE IN LATE WED
NIGHT. MAY SEE PRECIP CONFINED TO THE NRN CWA AHEAD OF THE SYSTEM
THROUGH THU MORNING...THE WILL BE MORE LIKELY TO COVER MOST OF THE
AREA THU AFTERNOON INTO THU NIGHT. COULD SEE SOME MINOR MEASURABLE
SNOW OVER THE W THU EVENING INTO THU NIGHT...BUT DETAILS ARE STILL
TOO SKETCHY TO SAY WITH CONFIDENCE.
STILL SEE SOME POTENTIAL FOR A STRONGER SYSTEM TO MOVE THROUGH LATER
NEXT WEEKEND...BUT THAT IS HIGHLY UNCERTAIN. MODELS DO CONTINUE TO
SHOW COLDER AIR CAPABLE OF SUPPORTING LES AS THE WEEKEND GOES
ON...BUT EXACT EXTENT AND EVEN WIND DIRECTION IS UNCERTAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 632 AM EST MON DEC 7 2015
AN INCRSG S WIND WL SHIFT FOG/LIFR TO VLIFR CONDITIONS IMPACTING CMX
THIS MRNG TO THE N AND BRING A RETURN OF VFR WX THERE BY LATE MRNG.
BUT AT SAW...THE MORE FAVORABLE UPSLOPE S WIND WL DRAW LO CLDS/IFR
TO LIFR CONDITIONS INTO THAT SITE THIS MRNG. SHARPER DOWNSLOPE WIND
COMPONENT SHOULD BRING VFR CONDITIONS TO IWD THRU THE DAY. AS THE S
WIND STRENGTHENS AND DRAWS MOISTER AIR INTO THE UPR LKS TNGT IN THE
PRESENCE OF NOCTURNAL COOLING...LO CLDS AND MVFR/IFR CIGS WL SPREAD
INTO IWD AND CMX. EXPECT THE IFR CIGS TO PERSIST AT SAW AS WELL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 310 AM EST MON DEC 7 2015
THE PRESSURE GRADIENT WILL INCREASE THIS AFTERNOON INTO TONIGHT AS A
LOW PRESSURE SYSTEM MOVES INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25-30 KNOT WIND GUSTS TONIGHT INTO TUE MORNING. ANOTHER
PERIOD OF SOUTHERLY 25 KNOT WINDS IS EXPECTED THU INTO THU NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
527 AM CST MON DEC 7 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 342 AM CST MON DEC 7 2015
CLOUDS AND FOG THE MAIN CONCERN THIS MORNING...WITH A LARGE AREA OF
STRATUS AND FOG OVER THE SOUTHERN HALF TO THIRD OF THE FORECAST
AREA. THE LARGER SCALE MODELS ARE MISSING OUT ON A LOT OF
THIS...BUT THE SHORT RANGE HI RES MODELS ARE PICKING UP ON IT...AND
THE HRRR IS DOING A GOOD JOB WITH THE STRATUS AND FOG THIS MORNING
SO FAR. A WEAK WARM FRONT IS DUE TO MOVE THROUGH THE AREA LATE
THIS AFTERNOON AND TONIGHT. THE STRATUS WE HAVE NOW SHOULD BE
SWEPT NORTHEAST ACROSS THE AREA THROUGH THE REMAINDER OF THE
FORECAST AREA AHEAD OF THE FRONT...AND WHILE MIXING SHOULD HELP
DISSIPATE THE FOG...THE STRATUS SHOULD REMAIN WITH SLIGHTLY HIGHER
CEILINGS DURING THE DAY. THIS STRATUS TO KEEP TEMPERATURES DOWN
AND HAVE PUT THE MAX TEMPERATURE IN THE MIDDLE 30S TO NEAR 40.
TONIGHT AS THE WARM FRONT PASSES THROUGH THE CLOUD COVER SHOULD
KEEP US WARMER THAN THIS MORNING AND EXPECT LOWS IN THE MID 20S TO
NEAR 30...THOUGH THIS MAY BE TOO COLD AND WILL NOT BE SURPRISED IF
WE NEED TO RAISE MORE.
TUESDAY A WEAK SHORTWAVE WILL MOVE INTO THE AREA FROM THE
NORTHWEST... AND MOVE INTO THE FORECAST AREA BY LATE AFTERNOON. THIS
SHOULD BRING SOME CHANCES FOR RAIN TO MAINLY THE SOUTHERN HALF OF
THE FORECAST AREA DURING THE AFTERNOON. FOR NOW IT APPEARS THAT THE
PRECIPITATION SHOULD BE MAINLY RAIN...BUT WILL HAVE TO WATCH SURFACE
TEMPS CLOSELY AS IT COULD BE MIXED WITH SNOW AT TIMES.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 342 AM CST MON DEC 7 2015
RELATIVELY WARM WEATHER THROUGH THE REST OF THE WEEK...THEN FINALLY
COOLING DOWN TO NEAR-SEASONABLE THIS WEEKEND. A FEW CHANCES FOR
PRECIPITATION IN A FAIRLY ACTIVE PATTERN...LIGHT PRECIP TUESDAY
NIGHT THEN MORE SUBSTANTIAL PRECIP AMOUNTS POSSIBLE LATE WED NIGHT
INTO THURSDAY. ANOTHER CHANCE FOR LIGHT PRECIP AMOUNTS THROUGH THE
WEEKEND...WITH A POSSIBLE SHOT AT LAKE EFFECT SNOW ALONG THE SOUTH
SHORE LATE IN THE WEEKEND INTO EARLY NEXT WEEK. ALOFT 850MB TEMPS
ARE WARM AT ABOUT 0 TO +5C THROUGH THE WEEK...THEN FALLING TO A MORE
SEASONABLE -10 TO 0C THIS WEEKEND. /THOUGH THIS IS STILL A BIT ABOVE
NORMAL...INL SOUNDING CLIMATOLOGY AVERAGES AROUND -10C FOR MID
DECEMBER./
TUES NIGHT A WEAK STACKED LOW WILL MOVE SOUTHEAST ACROSS THE UPPER
MIDWEST AS IT TRAVERSES FROM NORTHWEST MINNESOTA INTO NORTHERN
WISCONSIN. THIS LOW WILL BE MAINLY EXITING THE REGION OVERNIGHT
TUESDAY WITH NOT MUCH OF A SURFACE FRONT REFLECTED AT THE SFC. WHILE
LOWS MAY REACH NEAR FREEZING AT THE SFC...ALOFT PROFILES WILL
SUPPORT MAINLY LIGHT RAIN/DRIZZLE...WITH THE SUB-FREEZING TEMPS
ARRIVING AT THE SFC WHEN MID/UPPER LEVELS DRY OUT TOWARDS WED
MORNING. A LOW/MID LEVEL RIDGE BUILDS IN BEHIND THE LOW FOR WED
RESULTING IN SOME CLEARING SKIES BUT NOT BEFORE HIGH CLOUDS BEGIN TO
INCREASE LATE IN THE DAY AHEAD OF THE NEXT SYSTEM.
LATE WED NIGHT INTO THURSDAY WILL BE THE BEST CHANCE FOR
PRECIPITATION ACROSS THE REGION AS A MORE ORGANIZED SYSTEM MOVES
ACROSS THE REGION. MID-LEVEL TROUGH EJECTING OUT OF THE GREAT BASIN
INTO THE NORTHERN HIGH PLAINS WED NIGHT WILL RESULT IN A SFC TROUGH
DEVELOPING IN RESPONSE ACROSS THE RED RIVER VALLEY...WITH A NORTHERN
STREAM UPPER LOW RESULTING IN A SFC LOW ACROSS CENTRAL MANITOBA.
TOWARDS THURSDAY THE BETTER LARGE-SCALE FORCING ARRIVES AS A POTENT
UPPER LOW MOVES ACROSS THE NORTHERN PLAINS AND A SFC LOW DEEPENS
ACROSS THE MN ARROWHEAD DURING THE DAY. SOUTHWESTERLY FLOW AHEAD OF
THE LOW WED NIGHT INTO THURSDAY WILL RESULT IN ABUNDANT MOISTURE AT
LOW/MID LEVELS...CAUSING PRECIPITABLE WATER VALUES TO REACH NEAR
THREE QUARTERS OF AN INCH...NEAR RECORD-BREAKING FOR THIS TIME OF
YEAR. THIS ABUNDANT MOISTURE COMBINED WITH THE WIDESPREAD LARGE-
SCALE LIFT DRIVEN BY THE POTENT UPPER LOW AND WARM AIR ADVECTION
AHEAD OF THE LOW WILL RESULT IN WIDESPREAD PRECIPITATION...MAINLY IN
THE FORM OF RAIN DURING THE DAY THURSDAY....BUT CHANGING TO SNOW
THURSDAY NIGHT AS THE DEEPENING LOW DRAWS IN COLDER AIR FROM THE
NORTHWEST. BY FRIDAY MORNING THE LOW BECOMES STACKED OVER
NORTHERN LAKE SUPERIOR RESULTING IN NORTH TO NORTHWESTERLY FLOW
ACROSS THE NORTHLAND...BRINGING A CHANCE FOR ACCUMULATING SNOWFALL
INTO FRIDAY MORNING BEFORE THE LOW LIFTS OFF THE NORTHWEST. THE
COLD AIR THIS SYSTEM WILL DRAW IN IS STILL VERY WARM...850MB TEMPS
BARELY DIPPING BELOW -5C...SO LAKE EFFECT POTENTIAL LOOKS TO BE
LIMITED.
WHILE THE RAIN/SNOW OCCURS ON THURSDAY INTO FRIDAY MORNING THERE
WILL BE A DEEP LONGWAVE TROUGH DEVELOPING ACROSS THE WESTERN HALF OF
THE LOWER 48...A SIGNIFICANT CHANGE IN THE SYNOPTIC-SCALE PATTERN.
THIS TROUGH WILL DIG DEEPER THAN EARLIER EVENTS THIS LATE FALL/EARLY
WINTER...WITH GUIDANCE LEANING TOWARDS A SLOWER PROGRESSION WHICH
WOULD CAUSE THE STORM TRACK TO BE ALIGNED TOO FAR EAST TO BRING ANY
SIGNIFICANT STORMS ASSOCIATED WITH THIS TROUGH AT LEAST THROUGH THE
WEEKEND. HOWEVER...AS THE LONGWAVE TROUGH DEVELOPS FRIDAY A MID-
LEVEL IMPULSE MOVING ACROSS THE SOUTHWESTERLY FLOW DEVELOPING COULD
RESULT IN A SFC LOW OVER THE UPPER MISSISSIPPI VALLEY FRIDAY INTO
FRIDAY NIGHT...WHICH COULD PULL IN ANOTHER SHOT AT COLDER AIR FROM
CANADA IN ADDITION TO THE CHANCE FOR PRECIPITATION. CONFIDENCE IS
NOT AS HIGH REGARDS TO TIMING...BUT THIS SET UP WOULD SEEM TO FAVOR
LIGHT PRECIP CHANCES INTO THE WEEKEND AS COLDER NORTHWESTERLY FLOW
DEVELOPS IN WAKE OF THIS SFC LOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 527 AM CST MON DEC 7 2015
MAINLY IFR CONDITIONS THROUGH THE TAF PERIOD AT MOST TAF
SITES...WITH A PERIOD OF IMPROVEMENT LATE THIS MORNING INTO THE
EARLY AFTERNOON BEFORE CONDITIONS DETERIORATE AGAIN TONIGHT.
LIFR/VLIFR FOG AND STRATUS ACROSS THE REGION THIS MORNING IS
GRADUALLY WANING AS MID/HIGH LEVEL CLOUDS MOVE ACROSS NORTHERN
MINNESOTA THIS MORNING...CAUSING CEILINGS AND VISIBILITIES TO
IMPROVE. THIS TREND WILL CONTINUE FROM WEST TO EAST...WITH A
STRONG LOW LEVEL JET DEVELOPING ACROSS NORTHERN MINNESOTA BY MID
MORNING...CAUSING LOW LEVEL WIND SHEAR AT BRD...HIB...AND
INL..PEAKING AROUND 15Z WITH 40KT WINDS AROUND 1500-2000 FEET
ABOVE THE GROUND. WILL LIKELY SEE CONDITIONS TRANSITION TO MVFR OR
VFR EVERYWHERE FOR A TIME THIS AFTERNOON BEFORE FOG/STRATUS
REDEVELOPS TONIGHT AND SPREADS ACROSS THE REGION RESULTING IN IFR
OR WORSE CONDITIONS. WINDS LIGHT OUT OF THE SOUTH TO SOUTHEAST
THIS MORNING...PICKING UP FOR A TIME MID MORNING INTO THE EARLY
AFTERNOON OUT OF THE SOUTH TO SOUTHWEST WITH PEAK GUSTS TO AROUND
20 KNOTS...THEN RETURNING TO LIGHT WINDS THIS EVENING.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 37 29 41 30 / 0 0 20 30
INL 39 27 41 26 / 0 0 10 20
BRD 39 27 41 29 / 0 0 30 30
HYR 40 27 42 30 / 10 10 20 40
ASX 42 31 44 31 / 0 10 10 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 8 AM CST THIS MORNING FOR MNZ034>038.
DENSE FOG ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR MNZ025-
026-033.
LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 AM CST TUESDAY
FOR LSZ140.
&&
$$
SHORT TERM...LE
LONG TERM...JJM
AVIATION...JJM
AREA FORECAST DISCUSSION...UPDATED
NWS OMAHA/VALLEY NE
737 AM CST MON DEC 7 2015
.UPDATE...
ISSUED AT 735 AM CST MON DEC 7 2015
FOG HAS LIFTED OR WILL CONTINUE TO LIFT IN WRN IA THE NEXT HOUR OR
SO. DENSE FOG ADVISORY CANCELLED A BIT EARLY.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
MAIN NEAR TERM CONCERN CONTINUES TO BE AN EXTENSIVE AREA OF DENSE
FOG ACROSS OUR WESTERN IOWA COUNTIES WHERE WE ALREADY HAVE A DENSE
FOG ADVISORY. SATELLITE IMAGERY SHOWS THIS CONTINUING INCH TO THE EAST
HOWEVER HIGH CLOUDS SPILLING OVERHEAD ARE MAKING IT TOUGH TO SEE
THE LOWER CLOUDS/VISIBILITIES. CALLS TO A FEW COUNTIES
ACKNOWLEDGED SOME ICE/FROST ON VEHICLES AND GRASSY SURFACES BUT SO
FAR NO IMPACTS ON ROADS WITH ROAD TEMPERATURES STILL IN THE UPPER
30S. BOTH HRRR AND RAP INDICATE THE FOG/STRATUS DECK RAPIDLY
SLIDING EAST OF THE CWA BY MID MORNING. DID REMOVE MONONA COUNTY
FROM THE ADVISORY AND EXTENDED THE REMAINDER OF THE ADVISORY UNTIL
14Z.
OTHERWISE...LATEST WATER VAPOR IMAGERY LOOP SHOWS A WEAK SHORTWAVE
TROUGH EXTENDING FROM EASTERN MT THROUGH NORTH CENTRAL COLORADO. AT
THE SURFACE...A TROUGH EXTENDS SOUTH FROM LOW PRESSURE OVER SOUTH
CENTRAL CANADA INTO WESTERN KANSAS AND EVENTUALLY THE TEXAS
PANHANDLE. THE WEAK SHORTWAVE WILL CONTINUE TO MOVE EAST THROUGH
NEBRASKA TODAY AND INTO THE GREAT LAKES REGION BY EARLY TONIGHT.
THE SFC TROUGH PASSAGE WILL BE BRIEF/WEAK AND SHOULD HAVE LITTLE
AFFECT ON ANY SENSIBLE WEATHER EXCEPT FOR A BRIEF/WEAK WIND SHIFT
THIS AFTERNOON FROM SOUTHWEST TO NORTHWEST.
MILD CONDITIONS WILL BE THE PRIMARY STORY THIS WEEK WITH
TEMPERATURES RUNNING CLOSE TO 15 TO EVEN 20 DEGREES ABOVE NORMAL.
ANOTHER MID LEVEL SHORTWAVE WILL DRIFT THROUGH THE AREA TUESDAY
WHICH BRINGS INCREASED LARGE SCALE LIFT...BUT LACK OF MOISTURE
KEEP POPS OUT OF THE FORECAST. MAY ONLY SEE AN INCREASE IN
HIGH/MID CLOUDS BUT A FEW SPRINKLES CANNOT BE COMPLETELY RULED
OUT. AN ASSOCIATED SFC TROUGH WILL PUSH THROUGH TUESDAY AFTERNOON
TURNING WINDS AGAIN FROM SOUTHWEST TO NORTHWEST WHICH SHOULD ALLOW
DECENT MIXING TO PUSH HIGHS INTO THE MID TO UPPER 50S...WITH SOME
LOWER 60S POSSIBLE ACROSS OUR SOUTHERN COUNTIES DEPENDING ON
EXTENT OF CLOUD COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
PATTERN BECOMES MORE ACTIVE TOWARD THE WEEKEND WHEN A DEEP TROUGH
DIGS ACROSS THE WESTERN STATES AND A FAIRLY TIGHT BAROCLINIC ZONE
SETS UP ACROSS THE NATION`S MID SECTION BY FRIDAY. THIS CONTINUES
TO LOOK LIKE A LOW QPF EVENT FOR OUR CWA AS MAIN RIBBON OF QPF
DEVELOPS ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTHEAST BY
SATURDAY NIGHT/EARLY SUNDAY. MAIN PCPN FOR OUR AREA MIGHT BE SOME
OVERRUNNING...BUT DETAILS THIS FAR OUT ARE STILL A LITTLE SKETCHY.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 520 AM CST MON DEC 7 2015
FOG HAS BEEN JUST EAST OF KOMA AND WILL PROBABLY STAY THERE BASED
ON MOST RECENT DATA FROM WEB CAMS IN COUNCIL BLUFFS. OTHERWISE
LOOK FOR VFR CONDITIONS THROUGH THE PERIOD. SOUTHERLY WINDS WILL
INCREASE AND BECOME WEST OR SOUTHWEST TODAY...THEN DROP BACK TO
SOUTH AND BECOME LIGHTER FOR TONIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...MILLER
SHORT TERM...KERN
LONG TERM...KERN
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
520 AM CST MON DEC 7 2015
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
MAIN NEAR TERM CONCERN CONTINUES TO BE AN EXTENSIVE AREA OF DENSE
FOG ACROSS OUR WESTERN IOWA COUNTIES WHERE WE ALREADY HAVE A DENSE
FOG ADVISORY. SATELLITE IMAGERY SHOWS THIS CONTINUING INCH TO THE EAST
HOWEVER HIGH CLOUDS SPILLING OVERHEAD ARE MAKING IT TOUGH TO SEE
THE LOWER CLOUDS/VISIBILITIES. CALLS TO A FEW COUNTIES
ACKNOWLEDGED SOME ICE/FROST ON VEHICLES AND GRASSY SURFACES BUT SO
FAR NO IMPACTS ON ROADS WITH ROAD TEMPERATURES STILL IN THE UPPER
30S. BOTH HRRR AND RAP INDICATE THE FOG/STRATUS DECK RAPIDLY
SLIDING EAST OF THE CWA BY MID MORNING. DID REMOVE MONONA COUNTY
FROM THE ADVISORY AND EXTENDED THE REMAINDER OF THE ADVISORY UNTIL
14Z.
OTHERWISE...LATEST WATER VAPOR IMAGERY LOOP SHOWS A WEAK SHORTWAVE
TROUGH EXTENDING FROM EASTERN MT THROUGH NORTH CENTRAL COLORADO. AT
THE SURFACE...A TROUGH EXTENDS SOUTH FROM LOW PRESSURE OVER SOUTH
CENTRAL CANADA INTO WESTERN KANSAS AND EVENTUALLY THE TEXAS
PANHANDLE. THE WEAK SHORTWAVE WILL CONTINUE TO MOVE EAST THROUGH
NEBRASKA TODAY AND INTO THE GREAT LAKES REGION BY EARLY TONIGHT.
THE SFC TROUGH PASSAGE WILL BE BRIEF/WEAK AND SHOULD HAVE LITTLE
AFFECT ON ANY SENSIBLE WEATHER EXCEPT FOR A BRIEF/WEAK WIND SHIFT
THIS AFTERNOON FROM SOUTHWEST TO NORTHWEST.
MILD CONDITIONS WILL BE THE PRIMARY STORY THIS WEEK WITH
TEMPERATURES RUNNING CLOSE TO 15 TO EVEN 20 DEGREES ABOVE NORMAL.
ANOTHER MID LEVEL SHORTWAVE WILL DRIFT THROUGH THE AREA TUESDAY
WHICH BRINGS INCREASED LARGE SCALE LIFT...BUT LACK OF MOISTURE
KEEP POPS OUT OF THE FORECAST. MAY ONLY SEE AN INCREASE IN
HIGH/MID CLOUDS BUT A FEW SPRINKLES CANNOT BE COMPLETELY RULED
OUT. AN ASSOCIATED SFC TROUGH WILL PUSH THROUGH TUESDAY AFTERNOON
TURNING WINDS AGAIN FROM SOUTHWEST TO NORTHWEST WHICH SHOULD ALLOW
DECENT MIXING TO PUSH HIGHS INTO THE MID TO UPPER 50S...WITH SOME
LOWER 60S POSSIBLE ACROSS OUR SOUTHERN COUNTIES DEPENDING ON
EXTENT OF CLOUD COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
PATTERN BECOMES MORE ACTIVE TOWARD THE WEEKEND WHEN A DEEP TROUGH
DIGS ACROSS THE WESTERN STATES AND A FAIRLY TIGHT BAROCLINIC ZONE
SETS UP ACROSS THE NATION`S MID SECTION BY FRIDAY. THIS CONTINUES
TO LOOK LIKE A LOW QPF EVENT FOR OUR CWA AS MAIN RIBBON OF QPF
DEVELOPS ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTHEAST BY
SATURDAY NIGHT/EARLY SUNDAY. MAIN PCPN FOR OUR AREA MIGHT BE SOME
OVERRUNNING...BUT DETAILS THIS FAR OUT ARE STILL A LITTLE SKETCHY.
&&
.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 520 AM CST MON DEC 7 2015
FOG HAS BEEN JUST EAST OF KOMA AND WILL PROBABLY STAY THERE BASED
ON MOST RECENT DATA FROM WEB CAMS IN COUNCIL BLUFFS. OTHERWISE
LOOK FOR VFR CONDITIONS THROUGH THE PERIOD. SOUTHERLY WINDS WILL
INCREASE AND BECOME WEST OR SOUTHWEST TODAY...THEN DROP BACK TO
SOUTH AND BECOME LIGHTER FOR TONIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...DENSE FOG ADVISORY UNTIL 8 AM CST THIS MORNING FOR IAZ055-056-
069-079-080-090-091.
&&
$$
SHORT TERM...KERN
LONG TERM...KERN
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
645 AM EST MON DEC 7 2015
.SYNOPSIS...
A MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS
SOUTHERN PA LATE TODAY. A SERIES OF LOW PRES SYSTEMS WILL TRACK
WELL WEST OF PA LATE IN THE WEEK...AS AN ANOMALOUS UPPER RIDGE
BUILDS ALONG THE EAST COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
11-3.9U LOOP AT 11Z SHOWING AREAS OF DENSE VALLEY FROM EXTENDING
FROM THE CENTRAL MTNS EASTWARD INTO THE SUSQ VALLEY. STRONG
INVERSION AND LOW DECEMBER SUN ANGLE WILL ALLOW FOG TO PERSIST
THROUGH LATE AM. DENSE FOG ADV REMAINS UP THRU 16Z.
APPROACHING UPPER LOW IS PRODUCING A BATCH OF SHOWERS ACROSS THE
OHIO VALLEY AT 11Z. HOWEVER...ALL NEAR TERM MDL GUIDANCE TRACKS
WEAKENING SFC LOW WELL SOUTH OF PA...WITH AIR MASS OVR PA
REMAINING TOO DRY TO SUPPORT PRECIP. THEREFORE...WILL CONTINUE TO
CARRY ONLY A SLIGHT CHC OF SHOWERS ACROSS SOMERSET/BEDFORD
COUNTIES LATER TODAY.
UPSTREAM SATL IMAGERY AND MDL RH FIELDS SUGGEST PATCHY AM
FOG WILL GIVE WAY TO MSUNNY SKIES ACROSS MOST OF CENTRAL PA.
EXCEPTION WILL BE SOMERSET/BEDFORD COS...WHERE INCREASING CLOUDS
EXPECTED THIS AFTN. HIGHS WILL BE FAIRLY UNIFORM...RANGING FROM
45-50F OVER MOST OF THE REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
UPPER LOW WILL PUSH EAST OF PA TONIGHT...AS SFC RIDGE BUILDS IN
FROM THE NORTHWEST. MCLEAR SKIES AND A NEARLY CALM WIND SHOULD
ONCE AGAIN PROMOTE AREAS OF LOW CLOUDS/FOG. WEAKEST GRADIENT AND
REGION MOST FAVORABLE FOR FOG WILL BE ACROSS THE ALLEGHENY PLATEAU
WITH ONLY PATCHY FOG LIKELY FURTHER EAST ACROSS THE SUSQ VALLEY.
SFC RIDGE OVR THE REGION SHOULD ENSURE A DRY TUESDAY WITH PASSING UPPER
LVL SHORTWAVE LIKELY TO PRODUCE NO MORE THAN SCT MID/HIGH LVL
CLOUDINESS. SUPERBLEND AND NEW ECME MOS INDICATE HIGHS IN THE 40S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MAIN FORECAST STORY THRU THE END OF THIS WEEK IS THE
CONTINUED MILD TEMPERATURES...AS ZONAL FLOW FLOODS THE CONUS WITH
PACIFIC AIR. NAEFS AND ECENS OUTPUT SHOWING A SERIES OF SFC LOWS
TRACKING NORTHWARD THRU THE GRT LKS LATE NEXT WEEK...AS ANOMALOUS
UPPER RIDGE BUILDS ALONG THE E COAST. HAVE INCLUDED A CHC OF SHRA
ASSOC WITH SHORTWAVE LIFTING UP THE OHIO VALLEY LATE WED/EARLY
THU. OTHERWISE...THE EXTENDED FCST APPEARS DRY AND INCREASINGLY
WARM BENEATH BUILDING RIDGE.
GEFS PLUME DATA AND ECEME MOS SUPPORT MIN TEMPS ABOVE FREEZING
ACROSS THE ENTIRE CWA THU-SUN AND MAX TEMPS AT LEAST 15F ABV
NORMAL.
SOME CHC OF SHOWERS TOWARD THE END OF THE FCST PERIOD...AS
SOUTHERN STREAM SHORTWAVE LIFTS THRU THE GRT LKS...PUSHING A COLD
FRONT INTO PA. LATEST GEFS OUTPUT SUGGESTS FRONT AND SHOWER THREAT COULD
ARRIVE BY SUNDAY...WHILE ECENS IS A SLOWER SOLUTION WITH DRY/VERY
WARM WX PERSISTING THRU SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
THE BIGGEST FORECAST QUESTION OVERNIGHT IS FOG FORMATION. CURRENT
HRRR AND RAP RUNS DECREASE THE FOG THROUGH MOST OF THE CENTRAL PA
BY 09Z...HOWEVER GIVEN THE LOW DEWPOINT DEPRESSIONS...CALM WINDS
AN STRONG INVERSION EXPECT CENTRAL TAF SITES AOO...UNV...IPT TO
SEE IFR AND LOWER CIGS AND VSBYS OVERNIGHT UNTIL MORNING. THERE
HAS BEEN SOME VARIABILITY IN VSBYS DUE TO THE FOG MOVEMENT.
EXPECT TEMPO GROUPS OF 1/4 MILE AT TIMES AT UNV AND AOO...AND MVFR
RESTRICTIONS DUE TO THE PATCHY NATURE OF THE FORMING FOG THROUGH
THE FIRST HALF OF THE OVERNIGHT HOURS. AS THE FOG/MIST BECOMES
ENTRENCHED BETWEEN 06Z TO 09Z...VSBYS WILL DECREASE AND REMAIN IFR
AND LOWER.
MAINLY VFR CONDS WILL PREVAIL AT JST AND BFD...DUE TO
THE DRY NW FLOW ALOFT. FOG/MIST THROUGH THE LOWER SUSQ IS AN
INTERESTING CONUNDRUM. THOUGH SOME HIGH CLOUDS PERSIST...CALMING
WINDS...DEWPOINT DEPRESSIONS OF CURRENT 4 DEGREES OR LESS...SHOULD
ALLOW FOR FOR DENSE FOG OVERNIGHT. EXPECT PERIODS OF IFR VSBYS AND
LOWER ESPECIALLY NEAR SUNRISE. THE FOG WILL SLOWLY LIFT/DISSIPATE
TOMORROW MORNING...THOUGH QUICKER THAN IT DID ON SUNDAY. SO
EXPECT VFR TO RETURN BY 15Z MON AT ALL SITES.
A MOISTURE-STARVED SOUTHERN STREAM SHORTWAVE WILL TRACK ACROSS
THE AREA MONDAY...POTENTIALLY BRINGING RESTRICTIONS TO KJST LATER
MONDAY AND SPREADING INTO MAINLY THE SOUTHERN HALF OF THE STATE
MON NIGHT.
OUTLOOK...
MON-MON NIGHT...CHANCE FOR MVFR CONDITIONS IN -SHRA ACROSS THE
SOUTHERN HALF OF PENN.
TUE...NO SIG WX EXPECTED.
TUE NIGHT-WED NIGHT...CHANCE FOR MVFR CIGS.
THU-FRI...MVFR POSS NW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR PAZ012-
017>019-025>028-034>036-041-045-046-049>053-056>059-063>066.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/MARTIN
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
540 AM CST MON DEC 7 2015
.AVIATION...
/12Z TAFS/
VFR CONDITIONS ARE EXPECTED ACROSS AREA SITES THROUGH THE FORECAST
PERIOD. LIGHT AND VARIABLE WINDS WILL PERSIST ACROSS THE AREA
TERMINALS THROUGH TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 400 AM CST MON DEC 7 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
ONE LAST COOL MORNING TODAY WITH A WARMING TREND BEGINNING AND
LASTING INTO AT LEAST FRIDAY. IT WILL BE A STRAIGHT TEMPERATURE
FORECAST AS NO PRECIPITATION IS EXPECTED IN THE SHORT AND MOSTLY
LONG TERM PERIODS.
WATER VAPOR AND RAP ANALYSIS DEPICTS AN EXITING TROUGH AXIS ACROSS
THE MID-MISSISSIPPI RIVER VALLEY WITH MID-LVL NORTHWEST FLOW OVER
TOP SURFACE HIGH PRESSURE CENTERED OVER THE LONE STATE STATE.
CLEAR SKIES ARE EXPECTED TODAY AND TOMORROW THAT...ALONG WITH A
SLOWLY MODIFYING AIRMASS...WITH PROMOTE A WARMING TREND THAT WILL
CONTINUE INTO MID AND LATE WEEK. MAX HIGHS TODAY SHOULD BE QUITE
SIMILAR TO YESTERDAY TO 1F DEGREE COOLER GIVEN THE SLIGHTLY LOWER
MIXING HEIGHTS. THE RESULTANT TEMPERATURES SUPPORTED BY THE
GFS/NAM SOUNDINGS FALL MUCH MORE IN LINE WITH THE MAVMOS VALUES
WITH SOME SLIGHT +1F DEGREE TWEAKS MADE GIVEN PAST TRENDS. MIXING
HEIGHTS WILL INCREASE TUESDAY WITH WARMER 925MB HEIGHTS THAT WILL
SUPPORT AN ADDITIONAL 2-4F DEGREES OVER TODAY`S HIGHS. MORNING
LOWS WILL NOT BE AS COOL TUESDAY VS. THIS MORNING AS WEAK SOUTH
WINDS SLOWLY INCREASE DEWPOINT VALUES.
LONG TERM (WEDNESDAY THROUGH SUNDAY)...
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED MID TO LATE WEEK AS
READINGS WILL LIKELY REACH INTO THE UPPER 70S AND LOW TO EVEN MID
80S ACROSS THE REGION. RAIN CHANCES WILL INCREASE AHEAD OF A FRONT
THAT COULD MOVE THROUGH LATE SATURDAY INTO SUNDAY.
A SUBTROPICAL SURFACE HIGH WILL BECOME ESTABLISHED OVER THE GULF
AND EXTEND TOWARDS SOUTH-CENTRAL TEXAS THROUGH MID TO LATE-WEEK.
THIS FEATURE...AND WITH THE MAIN JET STREAM WELL NORTH...WILL
CONTINUE TO FOSTER LOW-LVL WARMING WITH SOUTHWEST AND WEST FLOW IN
THE 925-700MB LAYER. THIS PATTERN IS ONE THAT ALLOWS HIGHER
TEMPERATURES TO BE ACHIEVED...ESPECIALLY GIVEN THE ADVERTISED WELL
MIXED PBL TRANSLATING THE COMPRESSIONALLY WARMED AIR DOWN TO THE
SURFACE. READINGS BY THURSDAY AND ESPECIALLY INTO FRIDAY WILL BE
7-15F DEGREES ABOVE NORMAL WITH RIO GRANDE LOCATIONS PUSHING INTO
THE MID TO UPPER 80S. KSAT WILL APPROACH 80F THURSDAY AND LIKELY
SURPASS 80F FRIDAY WITH KAUS COMING QUITE CLOSE AS WELL. FRIDAY
WILL ALSO BE QUITE BREEZY /20MPH WINDS & GUSTS TO 30MPH/ AHEAD OF
A DEVELOPING SYSTEM FARTHER WEST OVER THE FOUR CORNER REGION. BOTH
ECMWF AND GFS LONGER RANGE MOS VALUES ARE IN GOOD AGREEMENT OF
THESE VALUES WITH BUFR SOUNDINGS CONFIRMING THE STRONG LIKELIHOOD
OF WELL ABOVE NORMAL TEMPERATURES. MORNINGS LOWS WILL SLOWLY COME
UP AS WELL AS DEWPOINTS SLOWLY CLIMB THROUGH SATURDAY.
BY LATE WEEK AND OVER THE WEEKEND...A STRONG H5 TROUGH WILL DIG
ACROSS THE WESTERN BASIN. GFS AND EC DIVERGE ON THIS SYSTEM`S
PROGRESSIVENESS. OPERATIONAL GFS IS QUICKER TO MOVE IT THROUGH
VS. ECMWF THAT LAGS THE ENERGY BACK WEST. GFS ENSEMBLES SUGGEST A
SLIGHTLY LESS PROGRESSIVE SYSTEM VS. THE OPERATIONAL GFS RUN AND
HAVE WEIGHTED SATURDAY/SUNDAY TEMPS AND POPS MORE TOWARDS THE
ENSEMBLE MEAN. A COLD FRONT SHOULD MOVE THROUGH SOMETIME LATE
SATURDAY OR LATE SUNDAY. WILL NEED TO FINE TUNE THIS SECTION AS
SOLUTIONS CONVERGE ON BETTER SYSTEM TIMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 70 46 73 49 76 / 0 0 0 0 -
AUSTIN BERGSTROM INTL AIRPORT 69 42 73 47 75 / 0 0 0 0 -
NEW BRAUNFELS MUNI AIRPORT 69 44 74 49 76 / 0 0 0 0 -
BURNET MUNI AIRPORT 67 43 73 46 74 / 0 0 0 0 0
DEL RIO INTL AIRPORT 71 44 74 47 76 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 66 42 74 47 74 / 0 0 0 0 -
HONDO MUNI AIRPORT 69 43 74 47 76 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 67 44 73 48 75 / 0 0 0 0 -
LA GRANGE - FAYETTE REGIONAL 68 46 73 50 75 / 0 0 0 0 -
SAN ANTONIO INTL AIRPORT 71 46 75 50 75 / 0 0 0 0 0
STINSON MUNI AIRPORT 70 46 75 50 76 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...17
SYNOPTIC/GRIDS...ALLEN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
703 AM EST MON DEC 7 2015
.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM, WILL CROSS THE OHIO VALLEY TODAY.
HIGH PRESSURE WILL THEN BUILD IN BEHIND THIS SYSTEM FOR TONIGHT
AND TUESDAY. LOW PRESSURE WILL DEVELOP OFF THE CAROLINA COAST
TODAY AND DEEPEN AS IT MOVES NORTHEAST INTO THE WESTERN ATLANTIC.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST MONDAY...
WATCHING TWO AREAS OF PRECIPITATION TODAY. THE FIRST IS WITH AN
UPPER LOW THAT WAS TRACKING EAST INTO OHIO AT 4AM AND THE SECOND
WITH A DEVELOPING SURFACE LOW OFF THE CAROLINA COAST. WIDELY
SCATTERED RAIN HAD DEVELOPED ALONG ANS WEST OF A BLUEFIELD TO
BRISTOL LINE. TEMPERATURES WERE SLOWLY WARMING ON THE WEST SIDE OF
THE MOUNTAINS WITH DEW POINTS RISING INTO THE LOWER TO MIDDLE 30S.
THERE WERE A FEW MESONET SITES IN MERCER...TAZEWELL AND SMYTH
COUNTIES WHICH REPORTED TEMPERATURES BELOW JUST BELOW FREEZING.
THESE TEMPERATURES WILL RISE ABOVE FREEZING BY 9AM... IF THERE IS
ANY RAIN BEFORE THEN...A LIGHT GLAZE OF ICE ON ELEVATED SURFACES
WILL BE POSSIBLE. HRRR SHOWED THIS PRECIPITATION DISSIPATING AS IT
MOVED EAST THIS MORNING.
A LARGER AREA OF SHOWERS WAS CLOSER TO THE UPPER LOW AND WILL REACH
WESTERN SECTIONS OF THE COUNTY WARNING AREA AFTER NOON AND MOVE EAST
ACROSS THE FORECAST AREA BY 03Z/10PM. CLOUDS WILL SPREAD INTO THE
AREA A COUPLE HOURS AHEAD OF THE ARRIVAL OF THE SHOWERS. THE BUFKIT
FORECAST SHOWED SOME GOOD MID LEVEL LAPSE RATES AS THE COLD POOL AT
500 MB ASSOCIATED WITH THE UPPER LOW CROSSES THE REGION. MODELS HAVE
THE UPPER TROF AND DEEP MOISTURE EAST OF THE FORECAST AREA BY
MIDNIGHT. EXPECTING A LAYER OF SHALLOW LOW CLOUDS IN THE WESTERN
UPSLOPE AREAS OF SOUTHEAST WEST VIRGINIA OVERNIGHT. RAIN AND CLOUD
COVER WITH THE SOUTHEAST LOW WAS EXPECTED TO STAY SOUTHEAST OF THE
FORECAST AREA TODAY.
COUNTIES IN THE VIRGINIA AND NORTH CAROLINA PIEDMONT WILL HAVE THE
MOST SUNSHINE TODAY AND THEREFORE THE WARMEST MAXIMUM TEMPERATURES.
STAYED CLOSE TO LOCAL WRF AND THE LATEST RUNS OF GRIDDED LAMP
GUIDANCE FOR MAXIMUM TEMPERATURES THIS AFTERNOON. MODELS HAD MORE OF
A SPREAD WITH LOWS OVERNIGHT IN THE MOUNTAINS. TRENDED TOWARD COOLER
MAV NUMBERS FOR MINIMUM TEMPERATURES.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EST MONDAY...
WEAK HIGH PRESSURE WILL BE THE CONTROLLING FEATURE OF OUR WEATHER
PATTERN ON TUESDAY...WITH THE AXIS OF THE HIGH DRIFTING OFF THE
COAST LATE TUESDAY NIGHT AS OUR NEXT COLD FRONT APPROACHES FROM THE
MIDWEST REGION. WINDS WILL SHIFT SOUTHERLY AS THE HIGH DRIFTS EAST
WHICH...COMBINED WITH ABUNDANT SUNSHINE...WILL HELP PUSH AFTERNOON
TEMPERATURES INTO THE UPPER 40S/LOW 50S ACROSS THE MOUNTAINS...AND
INTO THE MID/UPPER 50S ACROSS THE PIEDMONT. LOW TEMPERATURES FOR
TUESDAY NIGHT WILL BE DEPENDENT ON ELEVATION...WITH THE RIDGES
HOLDING WARMER IN THE SOUTHWESTERLY WINDFLOW OFF THE SURFACE...WHILE
THE LOWER ELEVATIONS WILL DECOUPLE AND EXPERIENCE RADIATIONAL
COOLING. BELIEVE SOME OF THE HIGHER RIDGES WILL REMAIN IN THE
LOW/MID 40S OVERNIGHT...WHILE TEMPERATURES WILL FALL INTO THE UPPER
20S TO MID 30S IN LOWER ELEVATIONS.
CLOUDS WILL INCREASE DURING EARLY WEDNESDAY MORNING AS THE COLD
FRONT APPROACHES...WITH A FEW SHOWERS ENTERING THE AREA JUST BEFORE
SUNSET. SOUTHWESTERLY FLOW AHEAD OF THE FRONT WILL MAINTAIN MILD
TEMPERATURES...WITH HIGHS REACHING INTO THE 50S AREAWIDE. SHOWER
ACTIVITY WILL INCREASE ACROSS THE WESTERN RIDGES AFTER SUNSET...BUT
DO NOT EXPECT THIS ACTIVITY TO MAKE MUCH PROGRESS FURTHER EAST AS
WINDS SHIFT WEST NORTHWESTERLY WITH FRONTAL PASSAGE. DOWNSLOPE
WINDFLOW WILL CAUSE THE SHOWERS TO BREAK UP BY THE TIME THEY REACH
THE BLUE RIDGE. ONLY MODEST RAINFALL AMOUNTS ARE EXPECTED...PERHAPS
AROUND A TENTH OF AN INCH IN PORTIONS OF SOUTHEAST WEST VIRGINIA.
MAY SEE A FEW UPSLOPE SHOWERS LINGER ALONG THE WESTERN RIDGES
WEDNESDAY NIGHT...BUT BELIEVE THIS ACTIVITY WILL BE GONE BY SUNRISE
THURSDAY...WITH DRY CONDITIONS EXPECTED FOR THE REMAINDER OF THE
DAY. IT WONT TAKE LONG FOR WINDS TO SHIFT SOUTHWESTERLY AGAIN AS YET
ANOTHER UPPER LEVEL DISTURBANCE SETS UP OVER THE GREAT LAKES. AS
SUCH...MILD TEMPERATURES WILL CONTINUE.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 240 AM EST MONDAY...
THE SYNOPTIC WEATHER PATTERN THROUGH SATURDAY ACROSS THE CENTRAL AND
EASTERN PARTS OF THE COUNTRY TRANSITIONS INTO A NEARLY ZONAL PATTERN
WITH THE POTENTIAL FOR ONE WEAK DISTURBANCE CROSSING THE AREA ON
FRIDAY. THIS WILL ALLOW FOR A GENERAL TREND TOWARDS TEMPERATURES
EVEN HIGHER THAN NORMAL...BUT AS MUCH AS PERHAPS 15 DEGREES.
ISOLATED SHOWERS WILL BE POSSIBLE ACROSS PORTIONS OF MAINLY
SOUTHEAST WEST VIRGINIA ON FRIDAY. OTHERWISE THROUGH SATURDAY...
EXPECT PRECIPITATION FREE CONDITIONS ACROSS THE AREA.
THE FORECAST SPECIFICS AT THE END OF THE FORECAST CYCLE GET A BIT
MORE UNCERTAIN. WHILE GUIDANCE BETWEEN THE GFS AND ECMWF AGREE THERE
WILL BE A STRONG COLD FRONT PASSAGE EARLY NEXT WEEK...THEY DIFFER
REGARDING THE TIMING. THE ECMWF IS A LITTLE QUICKER IN BRINGING THE
FRONT THROUGH THE REGION DURING THE DAY MONDAY...WITH THE SLOWER GFS
ABOUT 6 TO 12 HOURS LATER. HOWEVER...BOTH MODELS ARE WITHIN SIX
HOURS IN REGARDS TO THE ONSET OF SOME PRE-FRONTAL RAIN SHOWERS
STARTING LATE SATURDAY NIGHT...WITH A CONTINUATION OF SHOWERS AHEAD
OF THE FRONT ON SUNDAY. OUR FORECAST WILL REFLECT THIS SCENARIO
SATURDAY NIGHT INTO SUNDAY. TEMPERATURES WILL REMAIN ON THE VERY
MILD SIDE...BUT PERHAPS A LITTLE COOLER GIVEN INCREASING CLOUD COVER
AND CHANCES OF RAIN SHOWERS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 655 AM EST MONDAY...
RADAR SHOWED SCATTERED LIGHT RAIN FROM THE NEW RIVER VALLEY INTO
SOUTHEAST WEST VIRGINIA THIS MORNING. CEILINGS JUST ALONG THE
WESTERN SLOPES WERE MVFR. VFR CLOUDS EXTENDED BACK INTO THE OHIO
VALLEY WHERE AN UPPER LOW WAS MOVING EAST. MORE PRECIPITATION WAS
UNDERNEATH THE UPPER LOW IN NORTHERN KENTUCKY AND SOUTHERN OHIO.
MODELS WERE IN GOOD AGREEMENT BRINGING THIS PRECIPITATION INTO THE
MOUNTAINS AFTER 16Z/NOON AND MOVING IT EAST THROUGHOUT THE DAY.
HIGH CONFIDENCE THAT SHOWERS WILL EXIT THE AREA AND BE EAST OF
KLYH AND KDAN BY MIDNIGHT TONIGHT.
MODERATE CONFIDENCE AS TO HOW LOW CEILINGS WILL BE IN THE WESTERN
UPSLOPE AREAS TONIGHT. CLOUDS WILL CLEAR OUT IN THE EAST ONCE THE
UPPER LOW MOVES THROUGH BUT KLWB AND KBLF WILL HAVE MVFR CEILINGS
THIS EVENING. BUFKIT SOUNDINGS SUGGESTED IFR CEILINGS WERE
POSSIBLE AT KBLF OVERNIGHT. EXPECT ANY CEILINGS THIS LOW WILL
REMAIN WEST OF KLWB.
.EXTENDED AVIATION DISCUSSION...
WEAK HIGH PRESSURE FOLLOWS THIS SYSTEM WITH A RETURN TO VFR ON
TUESDAY. ANOTHER WEAK UPPER LEVEL DISTURBANCE MAY BRING SOME MVFR
CIGS AND ISOLATED SHOWERS TO THE WESTERN SLOPES LATER
WEDNESDAY...OTHERWISE CONTINUED VFR INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 300 AM EST SUNDAY...
T1 LINE IS DOWN PREVENTING DISSEMINATION OF THE BLUEFIELD ASOS
OBSERVATION. THE FAA HAS OPENED A TROUBLE TICKET AND IS WORKING ON
THE ISSUE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...DS
AVIATION...AMS/PM
EQUIPMENT...JH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
955 AM MST MON DEC 7 2015
.UPDATE...
ISSUED AT 934 AM MST MON DEC 7 2015
PTL PROFILER SHOWS THE INCREASING WESTERLY FLOW AROUND 700 MB BEHIND
THE SHORTWAVE THAT HAS NOW MOVED OFF INTO NEBRASKA. HOW MUCH OF THIS
FLOW MIXES DOWN ONTO THE PLAINS WILL BE ONE OF THE FORECAST ISSUES
FOR TODAY. LATEST HRRR KEEPS THE WESTERLIES MAINLY NEAR THE
FOOTHILLS AND ACROSS THE NORTHERN PORTIONS OF THE EASTERN PLAINS
WITH A MORE SUBDUED S BECOMING SW FLOW OVER MOST OF THE REST OF
THE PLAINS. THIS IS IN GENERAL AGREEMENT WITH THE LAST NAM. WILL
HAVE TO KEEP AN EYE ON GUSTY WINDS IN THE FOOTHILLS OTHERWISE WIND
FORECASTS AND THE REST OF TODAYS GRIDS LOOK GOOD. AREAS OF
CLOUDINESS MOVING WITH THE FLOW WITH A GENERAL INCREASE TONIGHT
AHEAD OF ANOTHER WEAK FAST MOVING WAVE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 453 AM MST MON DEC 7 2015
SHORTWAVE TROUGH AXIS IS PAST AND THE WAVE SHAPED HAS CHANGED.
STRONGEST WINDS APPEAR TO HAVE SHIFTED BACK TO THE HIGHER MOUNTAIN
SLOPES. STILL POCKETS OF WIND MIXING DOWN ALONG THE LOWER
FOOTHILLS BUT NOTHING LIKE A FEW HOURS AGO WHEN THERE WAS A MORE
AMPLIFIED WAVE. EXPECT THIS WILL BE THE PATTERN FOR THE DAY WITH A
BIT OF A DECREASE IN SPEEDS BY AFTERNOON. MEANWHILE MOISTURE IS
SPREADING BACK ACROSS THE AREA AFTER A BREAK IN THE STRONG SUBSIDENCE
BEHIND THE TROUGH AXIS WITH THE WAVE CLOUD REDEVELOPING. LOTS OF
HIGH LEVEL MOISTURE UPSTREAM NOW...MAYBE FOREVER...THOUGH MODELS
DO SHOW A BIT OF A BREAK IN THE CLOUDS AGAIN THIS EVENING. FLOW
ALOFT INCREASES AGAIN WITH ANOTHER LITTLE RIPPLE IN THE FLOW BUT
THE WAVE STRUCTURE LOOKS MARGINAL. SOME INCREASE IN SPEEDS FOR THE
MOUNTAINS AND WITH A FAIRLY WELL MIXED AIRMASS...WE WILL PROBABLY
SEE SOME SPILLAGE INTO THE ADJACENT WIND SPOTS. BUT THE PLAINS
SHOULD JUST HAVE LIGHTER S-W WINDS ON THE RIDGES WITH NOT MUCH IN
THE LOW SPOTS.
I ADDED SOME MORE CLOUD COVER AND TAPERED TEMPS BACK A LITTLE THIS
AFTERNOON FOR THE EXPECTED CLOUD COVER...BUT IT IS A WARM AIRMASS
SO JUST A COUPLE DEGREES. MADE SOME MINOR ADJUSTMENTS TO TONIGHTS
LOWS AS WELL...WARMER IN THE WINDIER AREAS AND A BIT LOWER
ELSEWHERE...BUT THE CLOUD MAY REQUIRE A COUPLE MORE DEGREES OF
WARMING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 453 AM MST MON DEC 7 2015
THERE IS STRONG NORTHWESTERLY FLOW ALOFT ON TUESDAY WITH A JET
MAXIMUM TO OUR IMMEDIATE NORTH AND NORTHEAST. THE NORTHWESTERLY
FLOW ALOFT CONTINUES OVER THE CWA TUESDAY NIGHT INTO WEDNESDAY
WITH AN UPPER RIDGE OVER THE WESTERN UNITED STATES. THE
NORTHWESTERLY FLOW ALOFT INCREASES AGAIN LATER WEDNESDAY AND
WEDNESDAY NIGHT AS A JET MAXIMUM MOVES IN BY WEDNESDAY NIGHT.
THERE IS MAINLY DOWNWARD SYNOPTIC SCALE ENERGY PROGGED OVER THE
CWA TUESDAY THROUGH WEDNESDAY. THE BOUNDARY LAYER FLOW IS
DOMINATED BY DOWNSLOPING THROUGH THE PERIODS...DAY AND NIGHT. FOR
MOISTURE...THERE IS A TAD IN THE MOUNTAINS TUESDAY INTO TUESDAY
NIGHT THEN AGAIN WEDNESDAY EVENING...OTHERWISE THE CWA IS PRETTY
DRY. THE QPF FIELDS SHOW A TAD OF MEASURABLE PRECIPITATION OVER
THE NORTHWESTERN BORDER AREA OF THE CWA TUESDAY AND TUESDAY
EVENING. WILL GO WITH SOME MINOR POPS IN THE HIGH MOUNTAINS
TUESDAY AND TUESDAY NIGHT. THERE IS A BIT OF A MOUNTAIN WAVE SET
UP TUESDAY AFTERNOON INTO WEDNESDAY MORNING. I DO NOT THINK HIGH
WIND CRITERIA IS A THREAT AT THIS TIME...BUT IT WILL BE WINDY. FOR
TEMPERATURES...TUESDAY`S HIGHS ARE 1-2 C WARMER THAN TODAY`S.
WEDNESDAY`S HIGHS ARE UP A TAD AGAIN FROM TUESDAY`S. FOR THE
LATER DAYS...THURSDAY THROUGH SUNDAY...MODELS HAVE STRONG FLOW
ALOFT ON THURSDAY WITH A WEST-NORTHWESTERLY JET MAXIMUM ACROSS
NORTHERN COLORADO. BY FRIDAY...THE MODELS AGAIN SHOW AN UPPER
TROUGH OVER THE WESTERN UNITED STATES. NOW IT IS MUCH BROADER THAN
YESTERDAY`S 00Z RUNS INDICATED. THE GFS BRINGS IT ACROSS COLORADO
WITH A COUPLE PIECES OF ENERGY FRIDAY INTO SATURDAY MORNING. THE
ECMWF NOW CLOSES OFF A CIRCULATION NEAR THE FOUR CORNERS MID DAY
SATURDAY...THE GFS HAS THE TROUGH AXIS WELL EAST OF COLORADO AT
THAT TIME. YESTERDAY`S 00Z MODEL RUNS WERE IN MUCH BETTER
AGREEMENT WITH EACH OTHER. NOW THEY DO NOT AGREE AND THERE IS LESS
CONSISTENCY WITH BOTH CONCERNING THEIR OWN PREVIOUS RUNS. THE
ECMWF IS CONSIDERABLY SLOWER THAN THE GFS AT PRESENT. OH
WELL...THERE WILL CERTAINLY BE A SLEW OF VARIOUS SOLUTIONS THE
NEXT SEVERAL DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 934 AM MST MON DEC 7 2015
DENVER WINDS WILL BE TRICKY AT LEAST FOR AWHILE TODAY...RIGHT NOW
MOST OF THE LLWAS SHOWING SOUTH WINDS AND MAY TREND TOWARDS MORE
SW WITH TIME TODAY AND WILL ASSESS THIS. CLOSER TO THE FOOTHILLS
AT BJC CHANCE THE WESTERLIES WILL BREAK THROUGH.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SZOKE
SHORT TERM...GIMMESTAD
LONG TERM...RJK
AVIATION...SZOKE
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
310 PM CST MON DEC 7 2015
.SHORT TERM...(Tonight)
ISSUED AT 310 PM CST MON DEC 7 2015
Behind the weak boundary that moved through the area this morning,
high pressure is building back into the Midwest. The narrow sfc
ridge axis is slipping to the east and winds are picking up an
increasingly southerly component. Unfortunately, not much of a
change in the forecast in the wake of the weak wave. Dewpoints are
still in the mid to upper 30s, with persistent fog. The high
pressure and inversion aloft has trapped the low level moisture over
the region for days now, and no mixing has occurred to scour it out.
Whereas some areas have briefly improved visibilities this
afternoon, the concern for the overnight hours is redevelopment. The
fog clearing from west to east on sat imagery is largely a function
of the sun. Earlier this morning, fog developed well back to the
west into the stronger southerly winds through the overnight. May
be a bit of a repeat with the dense fog, particularly in eastern
Illinois. However, widespread fog is expected to develop to some
extent for most of Central Illinois. Temps tonight will be
relatively mild in the mid to upper 30s.
&&
.LONG TERM...(Tuesday through Monday)
ISSUED AT 310 PM CST MON DEC 7 2015
At least patchy fog will be in place across central and southeast
Illinois to start the day Tuesday. Still some question regarding how
widespread or thick it will be as southerly low-level flow will be
increasing across the area during the morning hours. However,
forecast soundings suggest a stout, near surface based, inversion
that should help to keep moisture trapped near the ground. Hedged
the temperatures toward things being a little cloudier/foggier, with
highs mainly near 50.
Several weak short waves will pass near the region in a quasi-zonal
flow from Tuesday night into Friday. However, in addition to being
weak, these waves will be lacking significant moisture and have
generally limited PoPs to Slight Chance levels with their passage.
A much stronger wave is still progged to impact the area over the
weekend, and should be accompanied by period of heavier rainfall. At
this point, the heaviest rainfall, and potential thunderstorms, is
likely to occur later Saturday into Saturday night. However, model
spread in the details is still significant, and confidence in the
details is low. The current deterministic GFS and ECMWF forecasts are
on the fast and slow sides respectively of their ensemble means.
Have basically gone with a persistence forecast until forecast
confidence grows to push it toward one model solution or another.
Regardless of which model comes closest to verifying, it will get
quite warm and humid (for December at least), with highs in the 60s
and dew points in the 50s for Saturday. Cooler condtions come in to
start next week behind the strong system, but temperatures should
still be above normal for mid December.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1212 PM CST MON DEC 7 2015
Persistent fog continues across PIA CMI and BMI. DEC and SPI
slipping into IFR this morning, but VLIFR dominates the northern
half of the state. Continuing it through the early afternoon...sun is
slowly working through the fog and improving conditions to the
west. Bigger concern will be the return of the fog tonight.
GFS/NAM MOS and LAMP guidance is not dropping the vis tonight, but
the HRRR and the fact that the llvl moisture is not going to be
mixing out is leaning the forecast in a different direction. Will
be a function of a brief wind maxima in the guidance that moves
through overnight and how much in the way of cirrus remains over
the region.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until 10 PM CST this evening for ILZ038-
043>046.
&&
$$
SHORT TERM...HJS
LONG TERM...BAK
AVIATION...HJS
AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
1221 PM CST MON DEC 7 2015
.UPDATE...
ISSUED AT 1044 AM CST MON DEC 7 2015
High pressure ridge axis over Central Illinois this morning, with
plenty of low level moisture trapped at the surface. Under the
ridge with light winds last night, the high RH resulted in fog
that is slow to burn off yet again this morning. Dense fog
advisory is in place for much of ILXs CWA. Patchy improvement is
finally starting to show with some reports, but automated
observations are a bit behind the trend. Will be watching closely
to make the decision as to whether or not an extension in time
will be needed for the advisory. In addition, the thick fog has
delayed the warm up this morning and have knocked the high temps
down a degree or so. Only minor adjustments to the forecast here
and there...for now.
&&
.SHORT TERM...(Today)
ISSUED AT 250 AM CST MON DEC 7 2015
Main forecast challenge in the short term will be coverage of fog
and low cloud cover today and affect on afternoon temperatures.
Latest surface analysis indicates the weak weather system that
affected the area late yesterday afternoon and early evening with
the light rain has shifted well off to our east early this morning.
High pressure centered over northwest Missouri with the ridge axis
extending north through east central Iowa into Wisconsin. The ridge
axis by all models is forecast to shift across our area today. Quite
a bit of low cloud cover and areas of fog have been noted along the
ridge axis to our west with some of that is starting to edge into
our northwest early this morning.
RUC and NAM forecast soundings showing quite a bit of variability
with respect to the low level inversion that is forecast to set up
underneath the surface ridge axis today. Yesterday at this time, the
NAM was quite aggressive with the inversion and the depth of the low
level moisture trapped underneath it. However, this morning`s run
was backing off on the depth of the moisture and strength of the low
level inversion. Not seeing any strong reason for that to happen as
the surface ridge should track slowly east-southeast across the
region today with little in the way of significant flow noted on
soundings until later today. If the last several runs of the HRRR
are correct, the stratus and low visibilities will be with us
through this afternoon. For that reason, will continue with a bit
more pessimistic forecast with respect to cloud cover and
temperatures this afternoon. Have undercut MAV guidance numbers by a
category over most of our area this afternoon, with most of the highs
closer to the cooler MET guidance.
.LONG TERM...(Tonight through Sunday)
ISSUED AT 250 AM CST MON DEC 7 2015
Mild week on tap for the forecast area, with upper flow expected to
be of Pacific origin through the week. Latter part of the period
looking especially mild, as 850 mb temperatures by Friday evening
rise to near 10C. Highs in the 50s expected Tuesday-Wednesday before
60s start spreading in from the southwest. Widespread 60s expected
by Saturday.
Mostly dry weather expected through about Friday. Fast-moving upper
wave expected to take much of its energy a bit further north of us
Tuesday evening. An upper low is expected to close off within the
wave, but the ECMWF stands alone in having this (and better precip
chances) occur this far to the south; the remaining model suite has
a further north solution. Thus, will keep chances in the "silent 20"
range mainly northwest of I-55.
The more robust rain chances are expected late in the week. A fast
moving Canadian wave will dig southward into the Upper Mississippi
Valley on Thursday and zip eastward. We should stay dry from this
wave, but it will set the stage for a significant trough to dig
southward west of the Rockies late this week, helping to produce the
unseasonably mild temperatures. Unfortunately, there is a fairly
wide model spread as to how much this second trough digs. The ECMWF
continues to be much deeper as it draws energy from a Canadian wave
moving through the northern Plains, resulting in fairly intense
cyclogenesis over our area later in the weekend and an extended
period of showers/isolated storms. The GFS is much more weak/
progressive and has the cold front east of us by Sunday morning.
Still enough agreement to justify likely PoP`s Saturday night, but
confidence wanes on Sunday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1212 PM CST MON DEC 7 2015
Persistent fog continues across PIA CMI and BMI. DEC and SPI
slipping into IFR this morning, but VLIFR dominates the northern
half of the state. Continuing it through the early afternoon...sun is
slowly working through the fog and improving conditions to the
west. Bigger concern will be the return of the fog tonight.
GFS/NAM MOS and LAMP guidance is not dropping the vis tonight, but
the HRRR and the fact that the llvl moisture is not going to be
mixing out is leaning the forecast in a different direction. Will
be a function of a brief wind maxima in the guidance that moves
through overnight and how much in the way of cirrus remains over
the region.
&&
.ILX Watches/Warnings/Advisories...
Dense Fog Advisory until 3 PM CST this afternoon for ILZ027>031-
036>038-040>048-051>057-061>063.
&&
$$
UPDATE...HJS
SHORT TERM...Smith
LONG TERM...Geelhart
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
314 PM EST MON DEC 7 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS MOVE OFF THE MAINE COAST THIS
EVENING. HIGH PRESSURE WILL BUILD TOWARD THE AREA TONIGHT AND
REMAIN UNTIL WEDNESDAY. A TROUGH OF LOW PRESSURE WILL APPROACH
LATER THURSDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
19Z SURFACE ANALYSIS HAD COLD FRONT MOVING ACROSS NORTH-CENTRAL
AREAS. MRMS AND CANADIAN RADAR FROM QUEBEC SHOWED SOME LIGHT
RAIN/SNOW SHOWERS MOVING THROUGH FAR NORTHERN MAINE. KFVE REPORTED
A MIX RAIN/SNOW W/THE FROPA. TEMPS HAVE MAXED OUT WILL DROP AS
COLDER AIR MOVES INTO THE REGION TONIGHT. HRRR AND RAP GUIDANCE
SHOWED A BAND OF PRECIP DROPPING SE LATE THIS AFTERNOON INTO EARLY
EVENING W/THE FRONT. NOT MUCH MEASURABLE PRECIP IF ANY AT ALL
W/THE BAND. THE BAND OF PRECIP IS FORECAST TO WEAKEN AS IT DROPS
SE THIS EVENING. WX ELEMENT WILL BE LIGHT RAIN/SNOW SHOWERS. TEMPS
OVERNIGHT WILL DEPENDENT ON CLOUD COVER. NNW WINDS WILL DROP OFF
QUICKLY THIS EVENING AS HIGH PRES QUICKLY BUILDS E BEHIND THEFRONT.
AS WELL STATED BY THE MIDNIGHT CREW, THE BIGGEST FORECAST
CHALLENGES WILL BE THE EXTENT OF THE RADIATION INVERSION AS SHOWN
BY THE MODEL SOUNDINGS AND WHETHER CLOUDS WILL BE TRAPPED UNDER
THE SUBSIDENCE INVERSION. THIS WILL LEAD TO A CHALLENGE W/THE TEMP
FORECAST. CLEARING SKIES COULD READINGS TO DIP INTO THE LOWER
TEENS FOR NORTHERN AND WESTERN ZONES. A WIDESPREAD CLOUD COVER
WOULD KEEP TEMPS UP INTO THE MID TO UPPER 20S. ATTM, DECIDED TO
USE A CONSENSUS OF THE CONSRAW GUIDANCE AND SHOWED AT LEAST
PARTLY CLOUDY CONDITIONS FOR LATER TONIGHT. THIS SHOULD ALLOW FOR
SOME RADIATIONAL COOLING AND LEANED W/UPPER TEENS AND LOWERS 20S
NORTH AND WEST AND MID/UPPER 20S ELSEWHERE.
TUESDAY SHOULD FEATURE A LEAST PARTLY SUNNY DAY BUT COOLER W/HIGH
PRES BUILDING IN FROM THE W. THINKING HERE IS THAT AFTERNOON
TEMPERATURES WILL BE AT LEAST 5 TO 10 DEGREES COOLER THAN TODAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
EXPECT WEAK HIGH PRESSURE TO BE LOCATED OVER THE AREA TUESDAY
NIGHT. THIS SYSTEM WILL THEN GRADUALLY MOVE TO THE EAST WEDNESDAY.
CLOUDS WILL START TO INCREASE WEDNESDAY NIGHT AS WARM ADVECTION
TAKES PLACE IN THE RETURN FLOW BEHIND THE HIGH. SHOWERS ARE THEN
POSSIBLE ON THURSDAY AS A WARM FRONT APPROACHES. FOR TEMPERATURES
WILL USE THE BIAS CONSENSUS BLEND FOR HIGH AND THE CONSENSUS RAW
FOR LOWS BASED ON LASTEST VERIFICATION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
LOW PRESSURE IS EXPECTED TO PASS WELL TO THE NORTHWEST OF NEW
ENGLAND DURING THE DAY FRIDAY. HIGH PRESSURE CENTERED TO THE SOUTH
OF NEW ENGLAND WILL MOVE ACROSS THE REGION SATURDAY. ANOTHER LOW
PRESSURE SYSTEM WILL MOVE FROM THE WESTERN GREAT LAKES INTO
WESTERN QUEBEC PROVINCE EARLY SUNDAY AS STRONG HIGH PRESSURE MOVES
EASTWARD INTO THE ATLANTIC. LOW PRESSURE MAY DEVELOP OFF THE NEW
ENGLAND COAST MONDAY.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
NEAR TERM: EXPECTING MAINLY VFR THROUGH TUESDAY. THERE COULD BE A
BRIEF PERIOD OF MVFR THIS EVENING ACROSS THE NORTHERN TERMINALS
W/THE COLD FROPA.
SHORT TERM: VFR CONDITIONS ARE EXPECTED WEDNESDAY AND THURSDAY.
MVFR CONDITIONS EXPECTED FRIDAY. VFR CONDITIONS ARE THEN EXPECTED
SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. STAYED CLOSE TO THE DAYCREW`S
ASSESSMENT OF BRINGING WINDS UP TO 10-15 KTS SUSTAINED W/GUSTS TO
20 KTS. THIS WILL MAINLY BE ACROSS THE OUTER ZONES. WAVE HEIGHTS
WILL BE 3-4 INTO EARLY TUESDAY.
SHORT TERM: HAVE BLENDED THE NAM12 AND GFS40 FOR SUSTAINED WINDS.
FOR WAVES: OFF-SHORE WIND WAVE WILL DOMINATE ON WEDNESDAY. A
SOUTHERLY FETCH FROM THE GULF OF MAINE SOUTHWARD IS EXPECTED TO
DOMINATE FROM THURSDAY THROUGH THE WEEKEND. WAVES MAY APPROACH SCA
TURSDAY NIGHT. WILL USE THE NEAR SHORE WAVE MODEL TO POPULATE WAVE
GRIDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...MIGNONE
LONG TERM...MIGNONE
AVIATION...HEWITT/MIGNONE
MARINE...HEWITT/MIGNONE
AREA FORECAST DISCUSSION
NWS GRAY ME
1238 PM EST MON DEC 7 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL SAG SOUTH FROM CANADA AND MOVE OFFSHORE BY
THIS AFTERNOON. HIGH PRESSURE BUILDS IN FROM THE WEST TONIGHT.
LOW PRESSURE DEEPENS OFF THE VIRGINIA COAST TUESDAY MORNING AND
STAYS SOUTH OF THE GULF OF MAINE AND MOVES NORTHEAST. A RIDGE OF
HIGH PRESSURE CROSSES THE AREA WEDNESDAY. A WEAK DISTURBANCE WILL
CROSS THE REGION WEDNESDAY NIGHT INTO THURSDAY. A WARM FRONT
CROSSES THE AREA FRIDAY WITH MILD WEATHER EXPECTED FOR THE
UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1230 PM UPDATE...UPDATED TEMPERATURES TO MATCH UP WITH CURRENT OBS
AND TRENDS. FOG IS JUST ABOUT GONE IN THE CT RIVER VALLEY...SO IT
LOOKS LIKE THE CURRENT FORECAST OF FOG TO 18Z IS ACCURATE. THE
FORECAST CHALLENGE TONIGHT WILL BE WHETHER OR NOT TO BRING FOG
BACK INTO THE VALLEY AREAS...FORECAST RAP SOUNDINGS ARE INDICATING
THE PRESENCE OF FOG DURING THE OVERNIGHT. FOR NOW IT IS IN THE
FORECAST...BUT THIS IS SOMETHING TO LOOK INTO A BIT MORE FOR THE
AFTERNOON FORECAST PACKAGE.
1015 AM UPDATE...THE EDGE OF THE FOG IN THE CT RIVER VALLEY
CONTINUES TO SLOWLY RECEDE BIT BY BIT...BUT HAD TO EXTEND KEEPING
FOG/FZFG IN THE FORECAST INTO EARLY AFTERNOON.
9 AM UPDATE...THE FOG IS NOT NEARLY AS EXPANSIVE ACROSS THE CT
RIVER VALLEY THIS MORNING AS IT WAS YESTERDAY AND AT THE EDGES
IT IS STARTING TO BURN OFF. UPDATED THE WEATHER TO INCLUDE
FZFG/FG IN THE CT RIVER VALLEY THROUGH 15Z. THE ONLY OTHER CHANGES
NEEDED WERE TO ALIGN TEMPERATURES WITH CURRENT OBSERVATIONS AND
TRENDS.
UPDATE...
HAVE REMOVED FREEZING FOG AND MOST OF THE FOG FROM THE FORECAST
AFTER 12Z AS ONLY LEBANON AND KEENE ARE REPORTING ANYTHING. THIS
HAS BEEN THE CASE ALL NIGHT AND FEEL THE LOW LEVEL MOISTURE IS
JUST NOT THERE. OTHERWISE NO MAJOR CHANGES TO THE FORECAST. I DID
ADJUST SKY COVER AS CLEAR SKIES HAVE DEVELOPED OVER NORTHERN
SECTIONS. THIS WILL NOT LAST HOWEVER AS TODAY`S COLD FRONT IS
STILL TO OUR NORTH.
PREVIOUS DISCUSSION...
FREEZING FOG AND BLACK ICE LOOKING MUCH LESS PREVALENT TONIGHT AS
OPPOSED TO LAST NIGHT. THIS IS DUE TO LESS LOW LEVEL MOISTURE AND
THIN CLOUD COVER. HAVE CONTINUED MENTIONING IT IN PRODUCTS FOR A
COUPLE MORE HOURS AS THERE ARE MAY BE ISOLATED ICY PATCHES.
AFTER A CHILLY NIGHT TEMPERATURES REBOUND QUICKLY TODAY IN A DRY
AIRMASS. READINGS WILL WARM INTO THE UPPER 30S/LOWER 40S NORTH TO
UPPER 40S/LOWER 50S SOUTH. WINDS GRADUALLY TURN NORTHERLY TODAY AS
A WEAK BACKDOOR FRONT SAGS SOUTH OUT OF CANADA. NO PRECIPITATION
IS EXPECTED WITH THIS FEATURE AND IT WILL MOVE OFFSHORE IN THE
AFTERNOON HOURS. IT WILL HOWEVER INDUCE SOME CLOUD COVER IN THE
MOUNTAINS AND FOOTHILLS...AND DOWNSLOPING WILL KEEP THE COASTAL
PLAIN MOSTLY SUNNY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
TODAY WILL BE CHILLY WITH READINGS IN THE LOWER 20S NORTH TO
UPPER 20S/LOWER 30S SOUTH. A FEW TEENS MAY BE POSSIBLE ACROSS THE
NORTH DEPENDING ON CLOUD COVER. PW VALUES ARE FORECAST TO DROP
BELOW TWO-TENTHS OF AN INCH OVERNIGHT AND THIS IS AN INDICATOR OF
GOOD RADIATIONAL COOLING...AND A LACK OF CLOUDS. INDEED NORTHERLY
FLOW BECOMES LIGHT AND VARIABLE AS HIGH PRESSURE MOVES IN BEHIND
THE NOW WASHED OUT OFFSHORE FRONT...ANOTHER SIGNAL THAT CLOUDS MAY
BE BREAKING UP IN THE HIGHER TERRAIN. WHERE CLOUDS ARE ABSENT AND
WINDS DIMINISH WE MAY SEE SOME FOG DEVELOP.
TUESDAY`S WEATHER WILL ONLY BE SLIGHTLY IMPACTED BY A LARGE LOW
PRESSURE SYSTEM THAT IS PROGGED TO MOVE TOWARDS THE GULF OF MAINE
AND THEN TURN ENE WHEN IT BECOMES LEVEL WITH CAPE COD. WE WILL
SEE INCREASING CLOUD COVER BUT NO PRECIPITATION. IN THIS WAY
TEMPERATURES WILL BE LOWER THAN TODAY AND ONLY WARM INTO THE LOWER
40S OVER SOUTHERN SECTIONS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MODELS ARE IN GOOD AGREEMENT ON THE LONG WAVE PATTERN THROUGH
EARLY NEXT WEEKEND. NEARLY ZONAL FLOW WILL GRADUALLY AMPLIFY BY
LATE IN THE WEEK IN RESPONSE TO STRONG SHORTWAVE MOVING ONSHORE
OVER THE WESTERN CONUS. THIS GIVES RISE TO WESTERN TROUGH AND
EASTERN RIDGE FOR THE UPCOMING WEEKEND. INCREASING UNCERTAINTY
THEREAFTER...AS MODELS SOLUTIONS DIVERGE. HOWEVER...THROUGH D+6
THERE WILL BE A CONTINUED ABSENCE OF ARCTIC AIR AS PACIFIC FLOW
DOMINATES WITH WELL ABOVE NORMAL TEMPERATURES TO CONTINUE FOR THE
FORECAST AREA. IN THE DAILIES...SURFACE HIGH PRESSURE WILL SLIDE
OFFSHORE WEDNESDAY WITH DEVELOPING MILDER RETURN FLOW. SHORTWAVE
IMPULSE AND ASSOCIATED WEAK SURFACE REFLECTION CROSSES THE REGION
WITH A FEW SHOWERS WEDNESDAY NIGHT AND EARLY THURSDAY. WE`LL BE IN
BETWEEN SYSTEMS LATE THURSDAY INTO FRIDAY BEFORE NEXT SHORTWAVE
IMPULSE APPROACHES. AN ASSOCIATED WARM FRONT LIFTS NORTH ACROSS
THE AREA WITH A FEW CLOUDS AND SCATTERED SHOWERS. IN ITS
WAKE...BROAD SOUTHWEST FLOW AND RISING HEIGHTS WITH WELL ABOVE
NORMAL TEMPERATURES FOR NEXT WEEKEND. CONSIDERABLE UNCERTAINTY
THEREAFTER REGARDING HOW FAST SHORTWAVE ENERGY MANAGES TO BREAK
DOWN THE EASTERN RIDGE...AND DRIVE A SURFACE COLD FRONT ACROSS THE
REGION.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SHORT TERM...
1230 PM UPDATE...FOG HAS ALMOST COMPLETELY BURNED OFF IN THE CT
RIVER VALLEY WITH LEB HOLDING ON TO VLIFR CEILINGS. LEB SHOULD
COME BACK TO VFR IN THE NEXT HOUR TO HOUR IN A HALF. FOG MAY BE
ABLE TO DEVELOP AGAIN TONIGHT BUT RIGHT NOW THERE IS A LITTLE
UNCERTAINTY AS HIGH PRESSURE HAS WEAKENED AND THE LOW LEVEL
INVERSION DOES NOT QUITE AS STRONG AS IT HAS BEEN THE PAST COUPLE
DAYS.
PREVIOUS DISCUSSION...VFR CONDITIONS TO PREVAIL EXCEPT IN PATCHY
DENSE FZFG...MAINLY AT KLEB...KHIE...AS WELL AS FG AT KRKD THROUGH
13Z TODAY AND AGAIN LATE TONIGHT.
LONG TERM...
THU...SCT MVFR PSBL IN -SHRA/-SHSN.
&&
.MARINE...
SHORT TERM...WINDS INCREASE AND WE MAY SEE A FEW GUSTS NEAR 20 KTS
LATE TONIGHT INTO TUESDAY...HOWEVER EXPECT GUSTS TO REMAIN SUB-
SCA.SEAS SHOULD REMAIN 2-4 FT.
LONG TERM...
THU...SMALL CRAFT POSSIBLE OUTSIDE THE BAYS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...KISTNER
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1126 AM EST MON DEC 7 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS THE REGION THIS AFTERNOON. HIGH
PRESSURE BUILDS OVER THE AREA TONIGHT AND REMAIN UNTIL WEDNESDAY.
A TROUGH OF LOW PRESSURE WILL APPROACH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1120 AM UPDATE...UPDATED THE AFTERNOON TEMPS BY AT LEAST 3
DEGREES. SOME AREAS ALREADY NEAR PREVIOUS FORECAST HIGHS FOR THE
AFTERNOON. MORE SUN HAS ALLOWED THE TEMPS TO CLIMB. HRRR DOING
FINE W/CLOUDS AND POSSIBLE RAIN/SNOW SHOWER N AND W THIS
AFTERNOON.
PREVIOUS DISCUSSION... THE COLD FRONT WILL ENTER THE SAINT JOHN
VALLEY THIS AFTERNOON AND CONTINUE WEAKENING AS IT PROGRESSES
SOUTHWARD THROUGH THE AFTERNOON. THE ACTUAL FRONTAL PASSAGE MAY
PRODUCE A QUICK PERIOD OF DRIZZLE OR SNOW FLURRIES AS IT CROSSES.
THIS IS DUE TO A SHALLOW UNSTABLE LAYER UP TO H850. ANY
PRECIPITATION WILL BE VERY LIGHT AND CONFINED TO AROOSTOOK COUNTY.
THAT SAID...MOST GUIDANCE IS NOT SHOWING ANY POPS. MAY ADD A
NARROW BAND OF FLURRIES IN NORTHERN AROOSTOOK THIS AFTERNOON FOR
THE NEXT UPDATE. HIGH PRESSURE WILL BUILD RAPIDLY BEHIND THE FRONT
FOR TONIGHT WITH LIGHT WINDS. THE BIGGEST FORECAST CHALLENGES FOR
TONIGHT WILL BE THE EXTENT OF THE RADIATION INVERSION AND WHETHER
CLOUDS WILL BE TRAPPED UNDER THE SUBSIDENCE INVERSION. WITHOUT ANY
CLOUDS...TEMPERATURES COULD DIP INTO THE UPPER SINGLE DIGITS AND
LOWER TEENS FOR NORTHERN ZONES. HOWEVER...MORE WIDESPREAD
STRATOCUMULUS UNDER YET ANOTHER SUBSIDENCE INVERSION WILL HOLD
LOWS INTO THE MID TO UPPER 20S. WHILE DEW POINTS WILL DROP OFF
INTO THE UPPER TEENS TONIGHT...THIS IS FAR FROM A DRY ARCTIC AIR
MASS. HAVE PLAYED THE MIDDLE GROUND FOR THIS FORECAST...FOLLOWING
MOS GUIDANCE.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
RIDGE AXIS WL BE OVR CWA AT THE START OF THE SHORT TERM. SFC LOW
GOES WELL OFFSHORE WITH MINIMAL IMPACT ON CWA AS 1030MB HIGH KEEPS
IT WELL TO THE SOUTH. HIPRES SHIFTS EAST WED WITH RETURN FLOW
COMMENCING, HELPING TEMPS MODERATE THRU THE END OF THE SHORT TERM.
EXPECT H5 RIDGE ACRS THE STATE FOR WED WITH MILD ABV NORMAL TEMPS
FOR HIGHS ONCE AGAIN. TROF ROTATES ACRS AREA WED NGT WITH ISOLD SNOW
SHOWERS POSSIBLE IN WARM ADVECTION.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS NOTED BY PREVIOUS SHIFT HV KEPT POPS CONFINED TO SLT CHC/CHC
POPS THRU LONG TERM OWING TO MODEL DISCREPANCIES. 00Z GFS HAS SFC
LOW IN THE GULF OF MAIN FOR THUR WHEREAS GEM AND EC DO NOT
INDICATE THIS. PRETTY NEGLIGIBLE IN TERMS OF WX-MAKERS FOR AREA
THRU END OF THE PD WITH JUST MINOR S/WVS ROTATING THRU. BY LATE IN
THE PD DISCREPANCIES BCM EVEN BIGGER WITH SYSTEM DVLPNG ACRS THE
CENTER OF THE NATION.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
NEAR TERM: CONDITIONS WILL BE VFR TO START THIS MORNING EXCEPT FOG
ALONG THE COAST TO INCLUDE BHB. THE FOG WILL ERODE TOWARDS MID
MORNING OR EARLIER. MEANWHILE...MVFR CIGS WILL MOVE INTO FVE AND
PROGRESS SOUTH TO HUL BY LATE MORNING. THESE CIGS MAY MAKE IT TO
BGR AND BHB BY LATE AFTERNOON...BUT ONLY BRIEFLY. ALL SITES WILL
LIKELY BE VFR TONIGHT WITH THE POSSIBLE EXCEPTION OF FVE WITH
CONTINUING MVFR CIGS.
SHORT TERM: VFR EXPECTED THROUGH WED UNDER HIGH PRESSURE.
SOUTHERLY FLOW MAY BRING IN MVFR CIGS AS A TROUGH SWINGS THROUGH
AND BRINGS SNOW SHOWERS TO THE REGION FOR ALL BUT BHB. MVFR AND
POSSIBLE IFR RESTRICTIONS EXPECTED ON FRI MAINLY FOR NORTHERN
TERMINALS.
&&
.MARINE...
NEAR TERM: SSW WINDS WILL PICK UP THIS AFTERNOON AHEAD OF COLD
FRONT WITH A FEW GUSTS APPROACHING 20 KTS AND SEAS AROUND 4 FT.
WINDS WILL SHIFT TO THE NORTH BEHIND THE FRONT. THE COLD AIR
MOVING OVER THE WATERS WILL CONTINUE TO PRODUCE A FEW GUSTS TO 20
KTS TONIGHT.
SHORT TERM: SEAS AND WINDS WILL REMAIN BELOW SCA THRESHOLDS
THROUGH WED NIGHT. WAVES WILL APPROACH SCA THUR MORNING THROUGH
THE END OF THE PERIOD.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 PM EST MON DEC 7 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 410 PM EST MON DEC 7 2015
WV IMAGERY AND RAP ANALYSIS INDICATED AN UPSTREAM SHORTWAVE TROUGH
OVER THE UPPER MS VALLEY. AT THE SFC...A TROUGH EXTENDED INTO WRN MN
FROM LOW PRES OVER SRN MANITOBA. ALTHOUGH RADARS SHOWED SOME WEAK
RETURNS OVER NRN INTO CNTRL WI...NO SFC REPORTS OF PCPN WERE NOTED.
VIS SATELLITE INDICATED MID/HIGH CLOUDS MOVING ACROSS UPPER MICHIGAN
OVER THE LOW STRATUS AND FOG OVER MOST OF THE CNTRL AND ERN CWA.
CLOSER TO LAKE SUPERIOR IN THE WEST HALF...DOWNSLOPE SRLY FLOW HAS
HELPED SCOUR OUT THE LOW CLOUDS.
TONIGHT...EXPECT THAT WITH CONTINUED SRLY LOW LEVEL FLOW OF MOISTURE
BENEATH THE STRONG 875 MB INVERSION (12Z KGRB SOUNDING) THAT THE
FOG/STRATUS WILL PERSIST TONIGHT AND THICKEN WITH NOCTURNAL COOLING.
ALTHOUGH 850-500 MB QVECTOR CONV AND 280K ISENTROPIC LIFT AHEAD OF
THE SHRTWV IS EXPECTED...THE 850-700 MB DRY LAYER WILL BE STRONG
ENOUGH TO PREVENT ICE NUCLEI FROM REACHING THE LOWER MOIST LAYER.
SO...WILL MENTION DZ/FZDZ SPREADING WEST TO EAST MAINLY AFTER
03Z...ESPECIALLY WHERE UPSLOPE FLOW PREVAILS. ADDITIONAL MOISTENING
WITH THE FLOW OFF OF LAKE MICHIGAN WILL ALSO FAVOR GREATER DZ
POTENTIAL OVER THE ERN CWA. CLOSE TO LAKE SUPERIOR...EXPECT DRIER AND
SLIGHTLY WARMER CONDITIONS WITH LESS/NO PCPN/FOG.
TUESDAY...ANY LINGERING DZ/FZDZ IN THE MORNING OVER THE CNTRL AND
ERN CWA IS EXPECTED TO DEPART BY 15Z. HOWEVER...LOW CLOUDS SHOULD
LINGER WITH WEAK SSW LOW LEVEL FLOW AND LACK OF ANY DRY ADVECTION.
THIS SHOULD HELP LIMIT MAX TEMPS TO NEAR THE LOWER END OF GUIDANCE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 PM EST MON DEC 7 2015
ABOVE NORMAL TEMPERATURES WILL CONTINUE OVER THE UPPER GREAT LAKES
REGION THROUGH THE WORK WEEK AS SEVERAL WEAK WAVES MOVE FROM WEST
TO EAST ACROSS THE AREA. THIS WILL LEAD TO OCCASIONAL OPPORTUNITIES
FOR RAIN...WITH THE BETTER CHANCES FOR PRECIPITATION COMING THIS
WEEKEND INTO NEXT WEEK...AS AN UPPER TROUGH AMPLIFIES OVER THE
WESTERN CONUS AND EJECTS A COUPLE WAVES TOWARDS THE REGION THROUGH
THE MIDDLE OF NEXT WEEK.
THERE WILL BE TWO WEST-EAST WAVES AFFECTING THE REGION THIS
WEEK...THE FIRST OCCURRING ON TUESDAY NIGHT INTO WEDNESDAY AND A
SECOND...STRONGER WAVE THURSDAY AFTERNOON INTO FRIDAY. IN BOTH
CASES...EXPECT PRIMARILY RAIN TO OCCUR...BUT THERE COULD BE ENOUGH
COLD AIR WRAPPING IN ON THE BACK SIDE OF THE SECOND WAVE THURSDAY
NIGHT INTO FRIDAY TO LOWER WETBULB ZERO HEIGHTS TO LEAD TO SOME
SNOW OVER THE WESTERN U.P.. THAT COULD ALSO OCCUR WITH THE FIRST
WAVE...BUT THINK THE PRECIPITATION WILL LARGELY BE DONE BY THE TIME
THAT HAPPENS. QPF AMOUNTS TUESDAY NIGHT INTO WEDNESDAY MORNING WILL
RANGE FROM 0.05 TO 0.15IN...WITH THE GREATEST AMOUNTS OVER THE
EASTERN HALF OF THE CWA. THE SECOND EVENT WILL LARGELY DEPEND ON
THE TRACK OF THE LOW ACROSS THE AREA...BUT THINK THE HIGHEST
AMOUNTS WILL OCCUR OVER THE NORTHWEST HALF (OVER A QUARTER INCH OF
QPF POSSIBLE OVER WESTERN LAKE SUPERIOR).
FOR THE WEEKEND INTO NEXT WEEK...MODELS CONTINUE TO SHOW THE
POTENTIAL FOR A STRONGER SYSTEM TO MOVE THROUGH THE GREAT LAKES
REGION LATE THIS WEEKEND INTO NEXT WEEK. THIS IS DUE TO THE UPPER
TROUGH AMPLIFYING OVER THE WESTERN CONUS AND AN AMPLIFYING UPPER
RIDGE OVER THE EASTERN CONUS AND WESTERN ATLANTIC. THAT PUTS THE
REGION IN THE RIGHT LOCATION FOR A POSSIBLE STRONGER STORM MOVING
THROUGH SOMETIME IN THE 5-10 DAY TIME FRAME. WITH THE FAIRLY
AMPLIFIED TROUGH/RIDGE...SOME COLD AIR DOES TRY TO FILTER INTO THE
CWA FOR THE SECOND HALF OF THE WEEKEND...SO THAT DOES CREATE SOME
POTENTIAL FOR SNOW IF A SYSTEM OCCURS. THE 12Z RUNS LOOK TO
TRACK THE HEAVIEST QPF TO THE SOUTHEAST OF THE AREA...BUT IT IS
STILL 6 PLUS DAYS OUT AND WILL HAVE PLENTY OF TIME TO ADJUST AND
LOOK AT ANY POTENTIAL SYSTEMS OVER THE COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 125 PM EST MON DEC 7 2015
PERSISTENT LOW LEVEL SRLY UPSLOPE FLOW ALONG WITH ABUNDANT LOW LEVEL
MOISTURE ACROSS THE REGION WILL SUSTAIN LIFR TO OCNLY VLIFR
CONDITIONS THROUGH MOST OF THE TAF PERIOD. SOME DRIZZLE OR FREEZING
DRIZZLE MAY ALSO BE POSSIBLE LATE TONIGHT INTO TUE MORNING. AT
IWD/CMX...A MORE DOWNSLOPE WIND DIRECTION WILL KEEP MAINLY VFR
CONDITIONS UNTIL LATER THIS EVENING WHEN NOCTURNAL COOLING WILL HELP
SUPPORT STRATUS FORMATION WITH IFR CIGS. CONDITIONS WILL ONLY
GRADUALLY IMPROVE TUE MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST MON DEC 7 2015
THE PRESSURE GRADIENT WILL INCREASE TONIGHT AS A LOW PRESSURE SYSTEM
MOVES INTO NW ONTARIO. THIS WILL SUPPORT A PERIOD OF 25-30 KNOT WIND
GUSTS TONIGHT INTO TUE MORNING. ANOTHER PERIOD OF SOUTHERLY 25 KNOT
WINDS IS EXPECTED THU INTO THU NIGHT OVER ERN LAKE SUPERIOR AHEAD OF
A LOW PRESSURE SYSTEM MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
322 PM EST MON DEC 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM EST MON DEC 7 2015
00Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW A ZONAL SPLIT FLOW
OF PACIFIC AIR OVER SRN CANADA AND THE CONUS. SHRTWV RDG AXIS IS
MOVING INTO THE WRN GREAT LKS EARLY THIS MRNG...WITH WEAK SFC HI
PRES RDG STRETCHING FM NW ONTARIO ACRS WRN UPR MI TO STRONGER HI
PRES CENTERED OVER THE SRN PLAINS. ALTHOUGH THE AIRMASS OVHD IS
DRY...WITH 00Z PWAT AS LO AS ABOUT 0.20 INCH AT MPX...LINGERING LLVL
MSTR SHOWN ON LOCAL 00Z RAOBS TRAPPED UNDER LO SUBSIDENCE INVRN IS
CAUSING QUITE A BIT OF LO CLD/FOG OVER MUCH OF THE CWA IN THE
PRESENCE OF NOCTURNAL COOLING. THE FOG/STRATUS IS MOST EXTENSIVE
OVER THE INTERIOR W HALF OF THE CWA...WITH MORE HIER BASED SC
LINGERING OVER THE E...WHERE THE 00Z GRB/APX RAOBS SHOW MORE MSTR
NEAR HIER INVRN BASE. AREAS NEAR LK SUP W OF MUNISING...EXCEPT FOR
THE KEWEENAW...AND OVER THE SCENTRAL E OF IRON MTN ARE MOCLR...
PROBABLY DUE TO LIGHT DOWNSLOPE W TO SW WINDS IN THESE AREAS. THE LO
CLD AND FOG STRETCH W THRU MUCH OF MN. MORE HI CLD IN COMMA TAIL OF
NRN BRANCH SHRTWV/SFC LO TRACKING INTO MANITBOA IS STREAMING E INTO
MN AS WELL...BUT VERY DRY AIRMASS SHOWN ON THE ABERDEEN SDAKOTA AND
BISMARCK RAOBS IS PREVENTING ANY PCPN OR EVEN LOWER CLDS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON FOG/LO CLD
TRENDS.
TODAY...AS SFC HI PRES RDG SHIFTS TO THE E AND LO PRES MOVES INTO NW
ONTARIO...EXPECT A STEADY S WIND TO DVLP OVER UPR MI. NAM H95 RH...
WHICH HAS A GOOD HANDLE ON THE AREA OF LO CLDS RIGHT NOW...HINTS THE
AREA OF LO CLDS WL EXPAND TO ALL BUT THE NW CWA...WHERE THE S WIND
DOWNSLOPES. WHILE DAYTIME HEATING WL LIKELY LIMIT FOG COVERAGE...LO
SUN ANGLE WL PROBABLY NOT BE SUFFICIENT TO MIX OUT THE LO CLD. SO
TENDED TOWARD MORE CLD COVER EXCEPT IN THOSE DOWNSLOPE AREAS NEAR LK
SUP FM MUNISING TO BARAGA/THE KEWEENAW...ONTONAGON AND IRONWOOD.
LOWERED FCST MAX TEMPS A COUPLE DEGREES WHERE THE LO CLD IS EXPECTED
TO BE MOST EXTENSIVE. EXPECT THE WARMEST TEMPS INTO THE 40S IN THE
DOWNSLOPE AREAS NEAR LK SUP.
TNGT...AXIS OF DEEP LYR QVECTOR CNVGC IN COMMA TAIL OF SHRTWV MOVING
TO THE ENE TOWARD HUDSON BAY IS FCST TO SHIFT W-E ACRS THE CWA.
ALTHOUGH THIS FORCING WL NOT BE SUFFICIENT TO SATURATE THE VERY DRY
MID LVLS...LIFTING OF THE SUBSIDENCE INVRN WL ALLOW FOR A GREATER
DEPTH OF LLVL MSTR. MANY OF THE HIER RES MODELS GENERATE SOME LGT
PCPN...ESPECIALLY IN AREAS DOWNWIND OF LK MI IN THE EXPECTED LLVL
SSW FLOW. WL RETAIN SOME LO CHC POPS FOR DRIZZLE AND ADD SOME FOG IN
THE FCST FOR THIS AREA. THE SOMEWHAT HIER INVRN BASE WL ALSO ALLOW
FOR MORE LO CLDS TO EXPAND EVEN INTO THE DOWNSLOPE AREAS NEAR LK
SUP. TEMPS WL RUN WELL ABOVE NORMAL...MAINLY IN THE 30S...WARMEST
DOWNWIND OF LK MI.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 PM EST MON DEC 7 2015
ABOVE NORMAL TEMPERATURES WILL CONTINUE OVER THE UPPER GREAT LAKES
REGION THROUGH THE WORK WEEK AS SEVERAL WEAK WAVES MOVE FROM WEST
TO EAST ACROSS THE AREA. THIS WILL LEAD TO OCCASIONAL OPPORTUNITIES
FOR RAIN...WITH THE BETTER CHANCES FOR PRECIPITATION COMING THIS
WEEKEND INTO NEXT WEEK...AS AN UPPER TROUGH AMPLIFIES OVER THE
WESTERN CONUS AND EJECTS A COUPLE WAVES TOWARDS THE REGION THROUGH
THE MIDDLE OF NEXT WEEK.
THERE WILL BE TWO WEST-EAST WAVES AFFECTING THE REGION THIS
WEEK...THE FIRST OCCURRING ON TUESDAY NIGHT INTO WEDNESDAY AND A
SECOND...STRONGER WAVE THURSDAY AFTERNOON INTO FRIDAY. IN BOTH
CASES...EXPECT PRIMARILY RAIN TO OCCUR...BUT THERE COULD BE ENOUGH
COLD AIR WRAPPING IN ON THE BACK SIDE OF THE SECOND WAVE THURSDAY
NIGHT INTO FRIDAY TO LOWER WETBULB ZERO HEIGHTS TO LEAD TO SOME
SNOW OVER THE WESTERN U.P.. THAT COULD ALSO OCCUR WITH THE FIRST
WAVE...BUT THINK THE PRECIPITATION WILL LARGELY BE DONE BY THE TIME
THAT HAPPENS. QPF AMOUNTS TUESDAY NIGHT INTO WEDNESDAY MORNING WILL
RANGE FROM 0.05 TO 0.15IN...WITH THE GREATEST AMOUNTS OVER THE
EASTERN HALF OF THE CWA. THE SECOND EVENT WILL LARGELY DEPEND ON
THE TRACK OF THE LOW ACROSS THE AREA...BUT THINK THE HIGHEST
AMOUNTS WILL OCCUR OVER THE NORTHWEST HALF (OVER A QUARTER INCH OF
QPF POSSIBLE OVER WESTERN LAKE SUPERIOR).
FOR THE WEEKEND INTO NEXT WEEK...MODELS CONTINUE TO SHOW THE
POTENTIAL FOR A STRONGER SYSTEM TO MOVE THROUGH THE GREAT LAKES
REGION LATE THIS WEEKEND INTO NEXT WEEK. THIS IS DUE TO THE UPPER
TROUGH AMPLIFYING OVER THE WESTERN CONUS AND AN AMPLIFYING UPPER
RIDGE OVER THE EASTERN CONUS AND WESTERN ATLANTIC. THAT PUTS THE
REGION IN THE RIGHT LOCATION FOR A POSSIBLE STRONGER STORM MOVING
THROUGH SOMETIME IN THE 5-10 DAY TIME FRAME. WITH THE FAIRLY
AMPLIFIED TROUGH/RIDGE...SOME COLD AIR DOES TRY TO FILTER INTO THE
CWA FOR THE SECOND HALF OF THE WEEKEND...SO THAT DOES CREATE SOME
POTENTIAL FOR SNOW IF A SYSTEM OCCURS. THE 12Z RUNS LOOK TO
TRACK THE HEAVIEST QPF TO THE SOUTHEAST OF THE AREA...BUT IT IS
STILL 6 PLUS DAYS OUT AND WILL HAVE PLENTY OF TIME TO ADJUST AND
LOOK AT ANY POTENTIAL SYSTEMS OVER THE COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 125 PM EST MON DEC 7 2015
PERSISTENT LOW LEVEL SRLY UPSLOPE FLOW ALONG WITH ABUNDANT LOW LEVEL
MOISTURE ACROSS THE REGION WILL SUSTAIN LIFR TO OCNLY VLIFR
CONDITIONS THROUGH MOST OF THE TAF PERIOD. SOME DRIZZLE OR FREEZING
DRIZZLE MAY ALSO BE POSSIBLE LATE TONIGHT INTO TUE MORNING. AT
IWD/CMX...A MORE DOWNSLOPE WIND DIRECTION WILL KEEP MAINLY VFR
CONDITIONS UNTIL LATER THIS EVENING WHEN NOCTURNAL COOLING WILL HELP
SUPPORT STRATUS FORMATION WITH IFR CIGS. CONDITIONS WILL ONLY
GRADUALLY IMPROVE TUE MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 310 AM EST MON DEC 7 2015
THE PRESSURE GRADIENT WILL INCREASE THIS AFTERNOON INTO TONIGHT AS A
LOW PRESSURE SYSTEM MOVES INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25-30 KNOT WIND GUSTS TONIGHT INTO TUE MORNING. ANOTHER
PERIOD OF SOUTHERLY 25 KNOT WINDS IS EXPECTED THU INTO THU NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...JLB
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
126 PM EST MON DEC 7 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM EST MON DEC 7 2015
00Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW A ZONAL SPLIT FLOW
OF PACIFIC AIR OVER SRN CANADA AND THE CONUS. SHRTWV RDG AXIS IS
MOVING INTO THE WRN GREAT LKS EARLY THIS MRNG...WITH WEAK SFC HI
PRES RDG STRETCHING FM NW ONTARIO ACRS WRN UPR MI TO STRONGER HI
PRES CENTERED OVER THE SRN PLAINS. ALTHOUGH THE AIRMASS OVHD IS
DRY...WITH 00Z PWAT AS LO AS ABOUT 0.20 INCH AT MPX...LINGERING LLVL
MSTR SHOWN ON LOCAL 00Z RAOBS TRAPPED UNDER LO SUBSIDENCE INVRN IS
CAUSING QUITE A BIT OF LO CLD/FOG OVER MUCH OF THE CWA IN THE
PRESENCE OF NOCTURNAL COOLING. THE FOG/STRATUS IS MOST EXTENSIVE
OVER THE INTERIOR W HALF OF THE CWA...WITH MORE HIER BASED SC
LINGERING OVER THE E...WHERE THE 00Z GRB/APX RAOBS SHOW MORE MSTR
NEAR HIER INVRN BASE. AREAS NEAR LK SUP W OF MUNISING...EXCEPT FOR
THE KEWEENAW...AND OVER THE SCENTRAL E OF IRON MTN ARE MOCLR...
PROBABLY DUE TO LIGHT DOWNSLOPE W TO SW WINDS IN THESE AREAS. THE LO
CLD AND FOG STRETCH W THRU MUCH OF MN. MORE HI CLD IN COMMA TAIL OF
NRN BRANCH SHRTWV/SFC LO TRACKING INTO MANITBOA IS STREAMING E INTO
MN AS WELL...BUT VERY DRY AIRMASS SHOWN ON THE ABERDEEN SDAKOTA AND
BISMARCK RAOBS IS PREVENTING ANY PCPN OR EVEN LOWER CLDS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON FOG/LO CLD
TRENDS.
TODAY...AS SFC HI PRES RDG SHIFTS TO THE E AND LO PRES MOVES INTO NW
ONTARIO...EXPECT A STEADY S WIND TO DVLP OVER UPR MI. NAM H95 RH...
WHICH HAS A GOOD HANDLE ON THE AREA OF LO CLDS RIGHT NOW...HINTS THE
AREA OF LO CLDS WL EXPAND TO ALL BUT THE NW CWA...WHERE THE S WIND
DOWNSLOPES. WHILE DAYTIME HEATING WL LIKELY LIMIT FOG COVERAGE...LO
SUN ANGLE WL PROBABLY NOT BE SUFFICIENT TO MIX OUT THE LO CLD. SO
TENDED TOWARD MORE CLD COVER EXCEPT IN THOSE DOWNSLOPE AREAS NEAR LK
SUP FM MUNISING TO BARAGA/THE KEWEENAW...ONTONAGON AND IRONWOOD.
LOWERED FCST MAX TEMPS A COUPLE DEGREES WHERE THE LO CLD IS EXPECTED
TO BE MOST EXTENSIVE. EXPECT THE WARMEST TEMPS INTO THE 40S IN THE
DOWNSLOPE AREAS NEAR LK SUP.
TNGT...AXIS OF DEEP LYR QVECTOR CNVGC IN COMMA TAIL OF SHRTWV MOVING
TO THE ENE TOWARD HUDSON BAY IS FCST TO SHIFT W-E ACRS THE CWA.
ALTHOUGH THIS FORCING WL NOT BE SUFFICIENT TO SATURATE THE VERY DRY
MID LVLS...LIFTING OF THE SUBSIDENCE INVRN WL ALLOW FOR A GREATER
DEPTH OF LLVL MSTR. MANY OF THE HIER RES MODELS GENERATE SOME LGT
PCPN...ESPECIALLY IN AREAS DOWNWIND OF LK MI IN THE EXPECTED LLVL
SSW FLOW. WL RETAIN SOME LO CHC POPS FOR DRIZZLE AND ADD SOME FOG IN
THE FCST FOR THIS AREA. THE SOMEWHAT HIER INVRN BASE WL ALSO ALLOW
FOR MORE LO CLDS TO EXPAND EVEN INTO THE DOWNSLOPE AREAS NEAR LK
SUP. TEMPS WL RUN WELL ABOVE NORMAL...MAINLY IN THE 30S...WARMEST
DOWNWIND OF LK MI.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 310 AM EST MON DEC 7 2015
LONG TERM WILL SEE SEVERAL SHORTWAVES MAKING FOR A BUSIER
PATTERN...BUT AT THIS TIME PRECIP AMOUNTS LOOK TO BE MOSTLY
INSIGNIFICANT. MAY SEE SOME MORE SIGNIFICANT PRECIP NEXT
WEEKEND...BUT PREDICTABILITY IS QUITE LOW.
MAY SEE SOME LIGHT PRECIP OVER THE E ON TUE...MAINLY TUE
MORNING...AS A SHORTWAVE PASSES THROUGH. MODELS SHOW
ANOTHER...STRONGER...SHORTWAVE MOVING THROUGH THE REGION BETWEEN TUE
EVENING AND WED AFTERNOON. MODELS CONTINUE TO DISAGREE ON STRENGTH
OF THE SHORTWAVE...SO TIMING/COVERAGE/AMOUNTS OF PRECIP ARE
UNCERTAIN. COULD SEE SOME GREATER PRECIP AMOUNTS (GFS AND NAM
SHOWING UPWARDS OF ONLY 0.2 INCHES)...BUT MOST OF THAT SHOULD FALL
AS RAIN. COULD SEE SOME VERY MINOR MEASURABLE SNOW...BUT
INSIGNIFICANT REALLY.
PRECIP ASSOCIATED WITH NEXT SHORTWAVE LOOKS TO MOVE IN LATE WED
NIGHT. MAY SEE PRECIP CONFINED TO THE NRN CWA AHEAD OF THE SYSTEM
THROUGH THU MORNING...THE WILL BE MORE LIKELY TO COVER MOST OF THE
AREA THU AFTERNOON INTO THU NIGHT. COULD SEE SOME MINOR MEASURABLE
SNOW OVER THE W THU EVENING INTO THU NIGHT...BUT DETAILS ARE STILL
TOO SKETCHY TO SAY WITH CONFIDENCE.
STILL SEE SOME POTENTIAL FOR A STRONGER SYSTEM TO MOVE THROUGH LATER
NEXT WEEKEND...BUT THAT IS HIGHLY UNCERTAIN. MODELS DO CONTINUE TO
SHOW COLDER AIR CAPABLE OF SUPPORTING LES AS THE WEEKEND GOES
ON...BUT EXACT EXTENT AND EVEN WIND DIRECTION IS UNCERTAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 125 PM EST MON DEC 7 2015
PERSISTENT LOW LEVEL SRLY UPSLOPE FLOW ALONG WITH ABUNDANT LOW LEVEL
MOISTURE ACROSS THE REGION WILL SUSTAIN LIFR TO OCNLY VLIFR
CONDITIONS THROUGH MOST OF THE TAF PERIOD. SOME DRIZZLE OR FREEZING
DRIZZLE MAY ALSO BE POSSIBLE LATE TONIGHT INTO TUE MORNING. AT
IWD/CMX...A MORE DOWNSLOPE WIND DIRECTION WILL KEEP MAINLY VFR
CONDITIONS UNTIL LATER THIS EVENING WHEN NOCTURNAL COOLING WILL HELP
SUPPORT STRATUS FORMATION WITH IFR CIGS. CONDITIONS WILL ONLY
GRADUALLY IMPROVE TUE MORNING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 310 AM EST MON DEC 7 2015
THE PRESSURE GRADIENT WILL INCREASE THIS AFTERNOON INTO TONIGHT AS A
LOW PRESSURE SYSTEM MOVES INTO NW ONTARIO. THIS WILL SUPPORT A
PERIOD OF 25-30 KNOT WIND GUSTS TONIGHT INTO TUE MORNING. ANOTHER
PERIOD OF SOUTHERLY 25 KNOT WINDS IS EXPECTED THU INTO THU NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING INTO THE UPPER MS VALLEY.
OTHERWISE...WINDS WILL REMAIN BELOW 25 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLB
MARINE...TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
1154 AM CST MON DEC 7 2015
.UPDATE...
ISSUED AT 1154 AM CST MON DEC 7 2015
UPDATED FOR 18Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 342 AM CST MON DEC 7 2015
CLOUDS AND FOG THE MAIN CONCERN THIS MORNING...WITH A LARGE AREA OF
STRATUS AND FOG OVER THE SOUTHERN HALF TO THIRD OF THE FORECAST
AREA. THE LARGER SCALE MODELS ARE MISSING OUT ON A LOT OF
THIS...BUT THE SHORT RANGE HI RES MODELS ARE PICKING UP ON IT...AND
THE HRRR IS DOING A GOOD JOB WITH THE STRATUS AND FOG THIS MORNING
SO FAR. A WEAK WARM FRONT IS DUE TO MOVE THROUGH THE AREA LATE
THIS AFTERNOON AND TONIGHT. THE STRATUS WE HAVE NOW SHOULD BE
SWEPT NORTHEAST ACROSS THE AREA THROUGH THE REMAINDER OF THE
FORECAST AREA AHEAD OF THE FRONT...AND WHILE MIXING SHOULD HELP
DISSIPATE THE FOG...THE STRATUS SHOULD REMAIN WITH SLIGHTLY HIGHER
CEILINGS DURING THE DAY. THIS STRATUS TO KEEP TEMPERATURES DOWN
AND HAVE PUT THE MAX TEMPERATURE IN THE MIDDLE 30S TO NEAR 40.
TONIGHT AS THE WARM FRONT PASSES THROUGH THE CLOUD COVER SHOULD
KEEP US WARMER THAN THIS MORNING AND EXPECT LOWS IN THE MID 20S TO
NEAR 30...THOUGH THIS MAY BE TOO COLD AND WILL NOT BE SURPRISED IF
WE NEED TO RAISE MORE.
TUESDAY A WEAK SHORTWAVE WILL MOVE INTO THE AREA FROM THE
NORTHWEST... AND MOVE INTO THE FORECAST AREA BY LATE AFTERNOON. THIS
SHOULD BRING SOME CHANCES FOR RAIN TO MAINLY THE SOUTHERN HALF OF
THE FORECAST AREA DURING THE AFTERNOON. FOR NOW IT APPEARS THAT THE
PRECIPITATION SHOULD BE MAINLY RAIN...BUT WILL HAVE TO WATCH SURFACE
TEMPS CLOSELY AS IT COULD BE MIXED WITH SNOW AT TIMES.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 342 AM CST MON DEC 7 2015
RELATIVELY WARM WEATHER THROUGH THE REST OF THE WEEK...THEN FINALLY
COOLING DOWN TO NEAR-SEASONABLE THIS WEEKEND. A FEW CHANCES FOR
PRECIPITATION IN A FAIRLY ACTIVE PATTERN...LIGHT PRECIP TUESDAY
NIGHT THEN MORE SUBSTANTIAL PRECIP AMOUNTS POSSIBLE LATE WED NIGHT
INTO THURSDAY. ANOTHER CHANCE FOR LIGHT PRECIP AMOUNTS THROUGH THE
WEEKEND...WITH A POSSIBLE SHOT AT LAKE EFFECT SNOW ALONG THE SOUTH
SHORE LATE IN THE WEEKEND INTO EARLY NEXT WEEK. ALOFT 850MB TEMPS
ARE WARM AT ABOUT 0 TO +5C THROUGH THE WEEK...THEN FALLING TO A MORE
SEASONABLE -10 TO 0C THIS WEEKEND. /THOUGH THIS IS STILL A BIT ABOVE
NORMAL...INL SOUNDING CLIMATOLOGY AVERAGES AROUND -10C FOR MID
DECEMBER./
TUES NIGHT A WEAK STACKED LOW WILL MOVE SOUTHEAST ACROSS THE UPPER
MIDWEST AS IT TRAVERSES FROM NORTHWEST MINNESOTA INTO NORTHERN
WISCONSIN. THIS LOW WILL BE MAINLY EXITING THE REGION OVERNIGHT
TUESDAY WITH NOT MUCH OF A SURFACE FRONT REFLECTED AT THE SFC. WHILE
LOWS MAY REACH NEAR FREEZING AT THE SFC...ALOFT PROFILES WILL
SUPPORT MAINLY LIGHT RAIN/DRIZZLE...WITH THE SUB-FREEZING TEMPS
ARRIVING AT THE SFC WHEN MID/UPPER LEVELS DRY OUT TOWARDS WED
MORNING. A LOW/MID LEVEL RIDGE BUILDS IN BEHIND THE LOW FOR WED
RESULTING IN SOME CLEARING SKIES BUT NOT BEFORE HIGH CLOUDS BEGIN TO
INCREASE LATE IN THE DAY AHEAD OF THE NEXT SYSTEM.
LATE WED NIGHT INTO THURSDAY WILL BE THE BEST CHANCE FOR
PRECIPITATION ACROSS THE REGION AS A MORE ORGANIZED SYSTEM MOVES
ACROSS THE REGION. MID-LEVEL TROUGH EJECTING OUT OF THE GREAT BASIN
INTO THE NORTHERN HIGH PLAINS WED NIGHT WILL RESULT IN A SFC TROUGH
DEVELOPING IN RESPONSE ACROSS THE RED RIVER VALLEY...WITH A NORTHERN
STREAM UPPER LOW RESULTING IN A SFC LOW ACROSS CENTRAL MANITOBA.
TOWARDS THURSDAY THE BETTER LARGE-SCALE FORCING ARRIVES AS A POTENT
UPPER LOW MOVES ACROSS THE NORTHERN PLAINS AND A SFC LOW DEEPENS
ACROSS THE MN ARROWHEAD DURING THE DAY. SOUTHWESTERLY FLOW AHEAD OF
THE LOW WED NIGHT INTO THURSDAY WILL RESULT IN ABUNDANT MOISTURE AT
LOW/MID LEVELS...CAUSING PRECIPITABLE WATER VALUES TO REACH NEAR
THREE QUARTERS OF AN INCH...NEAR RECORD-BREAKING FOR THIS TIME OF
YEAR. THIS ABUNDANT MOISTURE COMBINED WITH THE WIDESPREAD LARGE-
SCALE LIFT DRIVEN BY THE POTENT UPPER LOW AND WARM AIR ADVECTION
AHEAD OF THE LOW WILL RESULT IN WIDESPREAD PRECIPITATION...MAINLY IN
THE FORM OF RAIN DURING THE DAY THURSDAY....BUT CHANGING TO SNOW
THURSDAY NIGHT AS THE DEEPENING LOW DRAWS IN COLDER AIR FROM THE
NORTHWEST. BY FRIDAY MORNING THE LOW BECOMES STACKED OVER
NORTHERN LAKE SUPERIOR RESULTING IN NORTH TO NORTHWESTERLY FLOW
ACROSS THE NORTHLAND...BRINGING A CHANCE FOR ACCUMULATING SNOWFALL
INTO FRIDAY MORNING BEFORE THE LOW LIFTS OFF THE NORTHWEST. THE
COLD AIR THIS SYSTEM WILL DRAW IN IS STILL VERY WARM...850MB TEMPS
BARELY DIPPING BELOW -5C...SO LAKE EFFECT POTENTIAL LOOKS TO BE
LIMITED.
WHILE THE RAIN/SNOW OCCURS ON THURSDAY INTO FRIDAY MORNING THERE
WILL BE A DEEP LONGWAVE TROUGH DEVELOPING ACROSS THE WESTERN HALF OF
THE LOWER 48...A SIGNIFICANT CHANGE IN THE SYNOPTIC-SCALE PATTERN.
THIS TROUGH WILL DIG DEEPER THAN EARLIER EVENTS THIS LATE FALL/EARLY
WINTER...WITH GUIDANCE LEANING TOWARDS A SLOWER PROGRESSION WHICH
WOULD CAUSE THE STORM TRACK TO BE ALIGNED TOO FAR EAST TO BRING ANY
SIGNIFICANT STORMS ASSOCIATED WITH THIS TROUGH AT LEAST THROUGH THE
WEEKEND. HOWEVER...AS THE LONGWAVE TROUGH DEVELOPS FRIDAY A MID-
LEVEL IMPULSE MOVING ACROSS THE SOUTHWESTERLY FLOW DEVELOPING COULD
RESULT IN A SFC LOW OVER THE UPPER MISSISSIPPI VALLEY FRIDAY INTO
FRIDAY NIGHT...WHICH COULD PULL IN ANOTHER SHOT AT COLDER AIR FROM
CANADA IN ADDITION TO THE CHANCE FOR PRECIPITATION. CONFIDENCE IS
NOT AS HIGH REGARDS TO TIMING...BUT THIS SET UP WOULD SEEM TO FAVOR
LIGHT PRECIP CHANCES INTO THE WEEKEND AS COLDER NORTHWESTERLY FLOW
DEVELOPS IN WAKE OF THIS SFC LOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1154 AM CST MON DEC 7 2015
MVFR CIGS WILL LIKELY CONTINUE ALONG THE NORTH SHORE OF LATE
SUPERIOR THIS AFTERNOON.... WITH VFR/MVFR CIGS/VIS CONTINUING ON
AND OFF AS A SFC FRONT PASSES THROUGH THE NORTHLAND THIS EVENING.
THE FROPA WILL DROP CONDITIONS BACK DOWN TO MVFR/IFR TONIGHT WITH
OCCASIONAL LIFR FOG EXPECTED... ESPECIALLY AT KDLH. EXPECT GUSTY
WINDS OUT OF THE SOUTH UP TO 20KTS TO CONTINUE THIS AFTERNOON
BECOMING LIGHT OVERNIGHT. A GRADUAL IMPROVEMENT TO MVFR/VFR WILL
COME AFTER 18Z TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 39 29 41 30 / 0 0 20 30
INL 40 27 41 26 / 0 0 10 20
BRD 40 27 41 29 / 0 0 30 30
HYR 41 27 42 30 / 10 10 20 40
ASX 43 31 44 31 / 0 10 10 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 AM CST TUESDAY
FOR LSZ140.
&&
$$
SHORT TERM...LE
LONG TERM...JJM
AVIATION...MCLOVIN
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
329 PM CST MON DEC 7 2015
.SHORT TERM: (Through Late Tonight)
Issued at 315 PM CST Mon Dec 7 2015
Low clouds have finally cleared to the east of the MS River as
lower trop southwesterly flow increases. I expect this clearing
trend to continue through the remainder of the afternoon into the
early evening. The late clearing east of the river however will
set the stage for fog potential later tonight in IL. Although the
surface ridge has retreated, southerly flow across IL is expected
to be quite light with dew points in the upper 30s. This should
allow for radiational fog to develop by late evening and progress
overnight. The HRRR and SREF is highlighting dense fog potential
for SW/SC IL and at this time I will be mentioning areas of dense
fog into Tuesday morning. Otherwise there will be a couple of
batches of high clouds tonight and slightly greater southerly flow
to the west of the MS river, keeping temps a bit higher than last
night.
Glass
.LONG TERM: (Tuesday through Next Monday)
Issued at 315 PM CST Mon Dec 7 2015
As discussed yesterday, a mild week is on tap with above normal
temperatures and a series of fast-moving short waves impacting
portions of the area within progressive flow aloft. There will also
be boughts of clouds with the shortwaves which will assist
modulating temperatures. The strongest shortwave forecast this
week will amplify as it traverses the CWA on Tuesday night.
Veering south to southwesterly low level flow ahead of the wave
should lead to a nice warm-up on Tuesday. There appears to be
sufficient forcing/ascent and moistening to merit continuing with
slight chance pops on Tuesday night. The GFS is strongest with
this system and the most bullish guidance with precipitation,
albiet very light. We will see some cooling in the wake of this
system for Wednesday, but temperatures will still be a good 10-15
degs above average. The next more prominent short wave will track
to our north across the upper MS Valley on Thursday, and this
will result in good southwesterly low level flow with high temps
20 or so degrees above average.
The very mild weather will continue through the end of the week
and into Saturday as a large scale pattern change evolves,
featuring the development of a deep and progressive long wave trof
over the western U.S. and its eventual eastward migration Sunday
into the first part of next week. There is considerable model
spread, both deterministic solutions and ensemble members, leading
to low confidence in forecast details. Prolonged low level
southerly flow will bring low level moisture back into the Mid MS
Valley ahead of a NE-SW oriented cold front, setting the stage for
an increased thunder threat. At this point there looks to be a
good chance of showers and thunderstorms somewhere centered on
Saturday night.
Glass
&&
.AVIATION: (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1144 AM CST Mon Dec 7 2015
Main forecast issue continues to be the ceilings for today.
IFR/MVFR cigs still expected to lift and scatter out from west to
east today across region. Already have some breaks in overcast
near KCOU, so have vfr conditions by 20z at KCOU, by 20z-21z for
rest of taf sites. Still some concern for fog/stratus development
once again for tonight. Best area to see this is KUIN, so added
tempo mvfr vsbys betweenn 08z and 12z Tuesday. Otherwise, rest of
taf sites have just added scattered stratus for now. Winds to
become light and southerly by tonight before picking up to near 15
kts from the south southwest on Tuesday.
Specifics for KSTL:
Main forecast issue continues to be the ceilings for today.
IFR/MVFR cigs still expected to lift and scatter out from west to
east today across region. Already have some breaks in overcast
near KCOU, so have mvfr clouds scattering out between 20z and 21z
for metro area. Still some concern for fog/stratus development
once again for tonight, but confidence is low right now, so just
added scattered stratus for now. Winds to remain light and
southerly before picking up to near 15 kts from the south
southwest 16z Tuesday.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1138 AM CST MON DEC 7 2015
.UPDATE...
ISSUED AT 735 AM CST MON DEC 7 2015
FOG HAS LIFTED OR WILL CONTINUE TO LIFT IN WRN IA THE NEXT HOUR OR
SO. DENSE FOG ADVISORY CANCELLED A BIT EARLY.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
MAIN NEAR TERM CONCERN CONTINUES TO BE AN EXTENSIVE AREA OF DENSE
FOG ACROSS OUR WESTERN IOWA COUNTIES WHERE WE ALREADY HAVE A DENSE
FOG ADVISORY. SATELLITE IMAGERY SHOWS THIS CONTINUING INCH TO THE EAST
HOWEVER HIGH CLOUDS SPILLING OVERHEAD ARE MAKING IT TOUGH TO SEE
THE LOWER CLOUDS/VISIBILITIES. CALLS TO A FEW COUNTIES
ACKNOWLEDGED SOME ICE/FROST ON VEHICLES AND GRASSY SURFACES BUT SO
FAR NO IMPACTS ON ROADS WITH ROAD TEMPERATURES STILL IN THE UPPER
30S. BOTH HRRR AND RAP INDICATE THE FOG/STRATUS DECK RAPIDLY
SLIDING EAST OF THE CWA BY MID MORNING. DID REMOVE MONONA COUNTY
FROM THE ADVISORY AND EXTENDED THE REMAINDER OF THE ADVISORY UNTIL
14Z.
OTHERWISE...LATEST WATER VAPOR IMAGERY LOOP SHOWS A WEAK SHORTWAVE
TROUGH EXTENDING FROM EASTERN MT THROUGH NORTH CENTRAL COLORADO. AT
THE SURFACE...A TROUGH EXTENDS SOUTH FROM LOW PRESSURE OVER SOUTH
CENTRAL CANADA INTO WESTERN KANSAS AND EVENTUALLY THE TEXAS
PANHANDLE. THE WEAK SHORTWAVE WILL CONTINUE TO MOVE EAST THROUGH
NEBRASKA TODAY AND INTO THE GREAT LAKES REGION BY EARLY TONIGHT.
THE SFC TROUGH PASSAGE WILL BE BRIEF/WEAK AND SHOULD HAVE LITTLE
AFFECT ON ANY SENSIBLE WEATHER EXCEPT FOR A BRIEF/WEAK WIND SHIFT
THIS AFTERNOON FROM SOUTHWEST TO NORTHWEST.
MILD CONDITIONS WILL BE THE PRIMARY STORY THIS WEEK WITH
TEMPERATURES RUNNING CLOSE TO 15 TO EVEN 20 DEGREES ABOVE NORMAL.
ANOTHER MID LEVEL SHORTWAVE WILL DRIFT THROUGH THE AREA TUESDAY
WHICH BRINGS INCREASED LARGE SCALE LIFT...BUT LACK OF MOISTURE
KEEP POPS OUT OF THE FORECAST. MAY ONLY SEE AN INCREASE IN
HIGH/MID CLOUDS BUT A FEW SPRINKLES CANNOT BE COMPLETELY RULED
OUT. AN ASSOCIATED SFC TROUGH WILL PUSH THROUGH TUESDAY AFTERNOON
TURNING WINDS AGAIN FROM SOUTHWEST TO NORTHWEST WHICH SHOULD ALLOW
DECENT MIXING TO PUSH HIGHS INTO THE MID TO UPPER 50S...WITH SOME
LOWER 60S POSSIBLE ACROSS OUR SOUTHERN COUNTIES DEPENDING ON
EXTENT OF CLOUD COVER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 328 AM CST MON DEC 7 2015
PATTERN BECOMES MORE ACTIVE TOWARD THE WEEKEND WHEN A DEEP TROUGH
DIGS ACROSS THE WESTERN STATES AND A FAIRLY TIGHT BAROCLINIC ZONE
SETS UP ACROSS THE NATION`S MID SECTION BY FRIDAY. THIS CONTINUES
TO LOOK LIKE A LOW QPF EVENT FOR OUR CWA AS MAIN RIBBON OF QPF
DEVELOPS ALONG THE FRONTAL BOUNDARY WELL TO OUR SOUTHEAST BY
SATURDAY NIGHT/EARLY SUNDAY. MAIN PCPN FOR OUR AREA MIGHT BE SOME
OVERRUNNING...BUT DETAILS THIS FAR OUT ARE STILL A LITTLE SKETCHY.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1135 AM CST MON DEC 7 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH INCREASING
HIGH LEVEL CLOUDS AFTER 00Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
UPDATE...MILLER
SHORT TERM...KERN
LONG TERM...KERN
AVIATION...FOBERT
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
ISSUED BY NATIONAL WEATHER SERVICE BROWNSVILLE TX
1055 AM CST MON DEC 7 2015
.AVIATION...FOR THE 18Z TAFS...
VFR THROUGH THE PERIOD. SFC HIGH PRESSURE WILL REMAIN ENTRENCHED
ACROSS THE HILL COUNTRY AND SOUTH TEXAS THROUGH THIS EVENING THEN
SPREAD EASTWARD INTO THE NORTHERN GULF COAST TUESDAY. A SFC TROUGH
WILL DEVELOP ACROSS THE HIGH PLAINS OF WEST TEXAS IN RESPONSE TO A
MID LEVEL DISTURBANCE MOVING ACROSS THE CENTRAL PLAINS TUESDAY.
THIS TROUGH WILL HELP ESTABLISH WINDS FROM THE SSW BY NOON
TUESDAY. A FEW HIGH CLOUDS EXPECTED TO MOVE ACROSS THE AERODROMES
BEGINNING THIS EVENING BUT NO BREAKS IN CATEGORY EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 540 AM CST MON DEC 7 2015/
AVIATION...
/12Z TAFS/
VFR CONDITIONS ARE EXPECTED ACROSS AREA SITES THROUGH THE FORECAST
PERIOD. LIGHT AND VARIABLE WINDS WILL PERSIST ACROSS THE AREA
TERMINALS THROUGH TUESDAY.
PREV DISCUSSION... /ISSUED 400 AM CST MON DEC 7 2015/
SHORT TERM (TODAY THROUGH TUESDAY)...
ONE LAST COOL MORNING TODAY WITH A WARMING TREND BEGINNING AND
LASTING INTO AT LEAST FRIDAY. IT WILL BE A STRAIGHT TEMPERATURE
FORECAST AS NO PRECIPITATION IS EXPECTED IN THE SHORT AND MOSTLY
LONG TERM PERIODS.
WATER VAPOR AND RAP ANALYSIS DEPICTS AN EXITING TROUGH AXIS ACROSS
THE MID-MISSISSIPPI RIVER VALLEY WITH MID-LVL NORTHWEST FLOW OVER
TOP SURFACE HIGH PRESSURE CENTERED OVER THE LONE STATE STATE.
CLEAR SKIES ARE EXPECTED TODAY AND TOMORROW THAT...ALONG WITH A
SLOWLY MODIFYING AIRMASS...WITH PROMOTE A WARMING TREND THAT WILL
CONTINUE INTO MID AND LATE WEEK. MAX HIGHS TODAY SHOULD BE QUITE
SIMILAR TO YESTERDAY TO 1F DEGREE COOLER GIVEN THE SLIGHTLY LOWER
MIXING HEIGHTS. THE RESULTANT TEMPERATURES SUPPORTED BY THE
GFS/NAM SOUNDINGS FALL MUCH MORE IN LINE WITH THE MAVMOS VALUES
WITH SOME SLIGHT +1F DEGREE TWEAKS MADE GIVEN PAST TRENDS. MIXING
HEIGHTS WILL INCREASE TUESDAY WITH WARMER 925MB HEIGHTS THAT WILL
SUPPORT AN ADDITIONAL 2-4F DEGREES OVER TODAY`S HIGHS. MORNING
LOWS WILL NOT BE AS COOL TUESDAY VS. THIS MORNING AS WEAK SOUTH
WINDS SLOWLY INCREASE DEWPOINT VALUES.
LONG TERM (WEDNESDAY THROUGH SUNDAY)...
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED MID TO LATE WEEK AS
READINGS WILL LIKELY REACH INTO THE UPPER 70S AND LOW TO EVEN MID
80S ACROSS THE REGION. RAIN CHANCES WILL INCREASE AHEAD OF A FRONT
THAT COULD MOVE THROUGH LATE SATURDAY INTO SUNDAY.
A SUBTROPICAL SURFACE HIGH WILL BECOME ESTABLISHED OVER THE GULF
AND EXTEND TOWARDS SOUTH-CENTRAL TEXAS THROUGH MID TO LATE-WEEK.
THIS FEATURE...AND WITH THE MAIN JET STREAM WELL NORTH...WILL
CONTINUE TO FOSTER LOW-LVL WARMING WITH SOUTHWEST AND WEST FLOW IN
THE 925-700MB LAYER. THIS PATTERN IS ONE THAT ALLOWS HIGHER
TEMPERATURES TO BE ACHIEVED...ESPECIALLY GIVEN THE ADVERTISED WELL
MIXED PBL TRANSLATING THE COMPRESSIONALLY WARMED AIR DOWN TO THE
SURFACE. READINGS BY THURSDAY AND ESPECIALLY INTO FRIDAY WILL BE
7-15F DEGREES ABOVE NORMAL WITH RIO GRANDE LOCATIONS PUSHING INTO
THE MID TO UPPER 80S. KSAT WILL APPROACH 80F THURSDAY AND LIKELY
SURPASS 80F FRIDAY WITH KAUS COMING QUITE CLOSE AS WELL. FRIDAY
WILL ALSO BE QUITE BREEZY /20MPH WINDS & GUSTS TO 30MPH/ AHEAD OF
A DEVELOPING SYSTEM FARTHER WEST OVER THE FOUR CORNER REGION. BOTH
ECMWF AND GFS LONGER RANGE MOS VALUES ARE IN GOOD AGREEMENT OF
THESE VALUES WITH BUFR SOUNDINGS CONFIRMING THE STRONG LIKELIHOOD
OF WELL ABOVE NORMAL TEMPERATURES. MORNINGS LOWS WILL SLOWLY COME
UP AS WELL AS DEWPOINTS SLOWLY CLIMB THROUGH SATURDAY.
BY LATE WEEK AND OVER THE WEEKEND...A STRONG H5 TROUGH WILL DIG
ACROSS THE WESTERN BASIN. GFS AND EC DIVERGE ON THIS SYSTEM`S
PROGRESSIVENESS. OPERATIONAL GFS IS QUICKER TO MOVE IT THROUGH
VS. ECMWF THAT LAGS THE ENERGY BACK WEST. GFS ENSEMBLES SUGGEST A
SLIGHTLY LESS PROGRESSIVE SYSTEM VS. THE OPERATIONAL GFS RUN AND
HAVE WEIGHTED SATURDAY/SUNDAY TEMPS AND POPS MORE TOWARDS THE
ENSEMBLE MEAN. A COLD FRONT SHOULD MOVE THROUGH SOMETIME LATE
SATURDAY OR LATE SUNDAY. WILL NEED TO FINE TUNE THIS SECTION AS
SOLUTIONS CONVERGE ON BETTER SYSTEM TIMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 70 46 73 49 76 / 0 0 0 0 -
AUSTIN BERGSTROM INTL AIRPORT 69 42 73 47 75 / 0 0 0 0 -
NEW BRAUNFELS MUNI AIRPORT 69 44 74 49 76 / 0 0 0 0 -
BURNET MUNI AIRPORT 67 43 73 46 74 / 0 0 0 0 0
DEL RIO INTL AIRPORT 71 44 74 47 76 / 0 0 0 0 0
GEORGETOWN MUNI AIRPORT 66 42 74 47 74 / 0 0 0 0 -
HONDO MUNI AIRPORT 69 43 74 47 76 / 0 0 0 0 0
SAN MARCOS MUNI AIRPORT 67 44 73 48 75 / 0 0 0 0 -
LA GRANGE - FAYETTE REGIONAL 68 46 73 50 75 / 0 0 0 0 -
SAN ANTONIO INTL AIRPORT 71 46 75 50 75 / 0 0 0 0 0
STINSON MUNI AIRPORT 70 46 75 50 76 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AVIATION...SCHOLL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
303 PM CST MON DEC 7 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 303 PM CST MON DEC 7 2015
CHALLENGES TONIGHT INCLUDE CLOUD TRENDS AND TEMPERATURES. WILL
FOLLOW A BLEND OF THE LATEST RAP 0.5 KM RELATIVE HUMIDITY OUTPUT
AND THE CIRA SYNTHETIC FOG PRODUCT...BOTH OF WHICH CLOSELY MATCH
CURRENT REALITY.
CLEARING LINE AS OF 07.20Z EXTENDS FROM NEAR EAU CLAIRE TO DECORAH...
MOVING TO THE EAST AROUND 25 MPH. BEFORE SUNSET...EXPECT AN HOUR
OR TWO OF INCREASING SUNSHINE AS CLOUDS CONTINUE TO DISSIPATE
FROM WEST TO EAST. HOWEVER...LOW CLOUDS EXPECTED TO REDEVELOP
ACROSS SOUTH-CENTRAL MN IN COOLER AIR MASS BEHIND THE DEPARTING
SHORT-WAVE ALOFT AND THEN MOVE OVER THE FORECAST AREA THIS
EVENING. SHOULD STILL SEE A RATHER PROGRESSIVE WEST TO EAST
MOVEMENT OF CLOUD COVER GIVEN LOW-LEVEL WINDS TURNING TO THE WEST
AROUND 20 KTS...BUT AREAS EAST OF THE MS RIVER LIKELY TO REMAIN
MOSTLY CLOUDY FOR A GOOD PORTION OF THE NIGHT. AS A RESULT...
INCREASED LOW TEMPERATURES IN THESE AREAS INTO THE MID 30S.
FARTHER WEST WHERE SOME CLEARING IS POSSIBLE...TEMPERATURES WILL
FALL INTO THE LOWER 30S...POSSIBLY INTO THE UPPER 20S FOR FAVORED
COLD SPOTS. ALSO ADDED SOME PATCHY FOG AFTER MIDNIGHT...BUT
COVERAGE/RELATIVE IMPACT WILL BE MUCH LESS THAN LAST NIGHT.
WHILE THERE MAY BE SOME PEAKS OF SUN EARLY TUESDAY...CLOUD COVER
WILL QUICKLY INCREASE FROM WEST TO EAST AHEAD OF THE NEXT SHORT-
WAVE ALOFT. INITIAL DRY AIR MASS BELOW 700 HPA WILL LIMIT PRECIP
TUESDAY AFTERNOON...BUT MAY SEE SOME RAIN REACH THE GROUND TUESDAY
EVENING AS LOWER LEVELS SATURATE AND 850 TO 700 HPA TROUGH MOVES
ACROSS NORTHERN WI. BEST CHANCES FOR MEASURABLE RAIN WILL BE ALONG
AND NORTH OF I-94...BUT EVEN THERE ONLY A FEW HUNDREDTHS ARE
FORECAST. LOOK FOR HIGHS TUESDAY IN THE MID TO UPPER 40S WITH
LIGHT SOUTHERLY WIND.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 303 PM CST MON DEC 7 2015
WEDNESDAY THROUGH SATURDAY...ABOVE NORMAL TEMPERATURES WILL
CONTINUE...GENERALLY 15 TO 20 DEGREES HIGHER THAN WHAT IS TYPICAL
THIS TIME OF YEAR. THESE TEMPERATURES WILL MAX OUT ON THURSDAY
GIVEN A VERY WARM START TO THE DAY (LOWS IN THE UPPER 30S TO NEAR
40 DEGREES) AND 925 HPA TEMPERATURES FROM +4 TO +7 CELSIUS. AS A
RESULT...EXPECT WIDESPREAD LOWER 50S FOR THURSDAY/S HIGHS.
TEMPERATURES WILL REMAIN ABOVE NORMAL SUNDAY INTO EARLY NEXT
WEEK...BUT WILL FALL TO SOMETHING MORE COMMON FOR MID-DECEMBER
WITH HIGHS BACK INTO THE 30S AFTER PASSAGE OF A STRONG COLD FRONT
ON SATURDAY.
PRECIP-WISE...ANOTHER PACIFIC SHORT-WAVE MOVES ACROSS THE UPPER
MIDWEST ON THURSDAY. THERE IS MODEST SPREAD AMONG THE SREF
MEMBERS CONCERNING THE STRENGTH AND TIMING OF THIS TROUGH...BUT
IT APPEARS THE BEST SATURATION/LIFT WILL PASS NORTH OF THE
FORECAST AREA. WILL CONTINUE THE IDEA OF CHANCE POPS NORTH OF I-94
WITH LITTLE TO NO ACCUMULATION FARTHER SOUTH. THERMAL PROFILE IS
WARM ENOUGH FOR ANYTHING THAT DOES ACCUMULATE TO FALL AS RAIN.
STILL WATCHING THE DEVELOPMENT OF A MUCH LARGER TROUGH ACROSS THE
WESTERN CONUS FOR THE WEEKEND. HOWEVER...THE 07.12Z ECMWF IS
SLOWER AND MUCH DEEPER WITH THIS FEATURE COMPARED TO ITS GFS
COUNTERPART. WILL KEEP BROAD BRUSH 20 TO 30 POPS FOR THE WEEKEND
INTO EARLY NEXT WEEK FOR NOW WITH THE GFS PRODUCING MOST OF ITS
PRECIP TO THE SOUTH AND EAST OF THE FORECAST AREA ALONG THE
PRIMARY BAROCLINIC ZONE...WHEREAS THE ECMWF/S SLOWER SOLUTION
BRINGS AN AREA OF PRECIP FARTHER WEST ACROSS PORTIONS OF THE
FORECAST AREA. AS NOTED ABOVE...TEMPERATURES WILL BE COOLER THIS
WEEKEND...SO THE POTENTIAL EXISTS FOR SOME MIXED PRECIP OR EVEN
SNOW. HOWEVER...CONFIDENCE IS LOW ON THE STORM TRACK AND THEREFORE
ITS THERMAL PROFILE. WILL BE ABLE TO FINE-TUNE FORECAST AS MODELS
WORK THROUGH SOME OF THESE DIFFERENCES OVER THE NEXT SEVERAL
CYCLES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1140 AM CST MON DEC 7 2015
IFR/MVFR CLOUDS REMAIN BELOW AN INVERSION. SOUNDINGS SUGGEST THAT
THE MVFR DECK AT KLSE WILL REMAIN THROUGH THE TAF PERIOD.
MEANWHILE KRST WILL GRADUALLY LOSE ITS IFR DECK LATE THIS EVENING.
WITH IT LOSING THIS LOW DECK...SEVERAL OF THE MOS GUIDANCE SHOW
THAT DENSE FOG WILL ONCE AGAIN DEVELOP BETWEEN 08.10Z AND 08.14Z.
HOWEVER THIS GUIDANCE IS ALSO OVERDOING THE FOG RIGHT NOW...SO
CONFIDENCE IS NOT THAT HIGH. DUE TO THIS...JUST WENT WITH A TEMPO
1 STATUE MILE WITH BKN005 DECK DURING THIS TIME FRAME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...BOYNE