Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/15/13
AREA FORECAST DISCUSSION
NWS MIAMI FL
925 PM EDT SUN APR 14 2013
.UPDATE...
THE EVENING UPDATES WILL ONLY NEED SOME MINOR ADJUSTMENTS BASED ON
CURRENT TRENDS MAINLY FOR TEMPERATURES AND CLOUD COVER. THE HRRR
HANDLED THE AFTERNOON AND EVENING CONVECTION VERY WELL ACROSS THE
AREA WITH ONLY SCATTERED SHOWERS AND A FEW THUNDERSTORMS OVER THE
NORTHWEST INTERIOR (SOUTHWEST TO WEST OF LAKE OKEECHOBEE) WITH
RADAR SIGNATURES INDICATING ONLY GARDEN VARIETY STORMS. MOST OF
THE ACTIVITY HAS NOW MOVED NORTH OF THIS AREA. THE OTHER CONCERN
WILL BE FOR LATE NIGHT FOG FORMATION ACROSS THE INTERIOR AS THIS
AREA HAD GOOD COVERAGE EARLY THIS MORNING. CONDITIONS WILL BECOME
FAVORABLE EARLY ON WITH A CLEARING SKY AND A SOUTHEAST WIND
BECOMING LIGHT ALONG WITH THE GULF SEA BREEZE CIRCULATION
DISSIPATING. HOWEVER, THE HRRR HINTS THAT THE LINE OF CONVECTION
IN THE GULF OF MEXICO WILL SHIFT SOUTH AS THE NIGHT PROGRESSES
WITH THE MID LEVEL TROUGH LIFTING EAST INTO THE ATLANTIC. WHILE
MOST OF THE SHOWER ACTIVITY WILL HAVE DISSIPATED BY THE TIME THE
LINE REACHES SOUTH FLORIDA, THERE COULD BE ENOUGH CLOUD COVER TO
POTENTIALLY INHIBIT THE DEVELOPMENT OF FOG. HOWEVER, THE
INCREASING CLOUDINESS ALSO WILL NOT OCCUR UNTIL WELL AFTER
MIDNIGHT GIVING TIME FOR THE FOG TO FORM. GIVEN THIS AND THE FACT
THAT SHOWER ACTIVITY HAS OCCURRED LEAVING THE LOW LEVELS QUITE
MOIST WILL LEAVE MENTION OF AREAS OF FOG ACROSS THE INTERIOR.
KOB
&&
.PREV DISCUSSION... /ISSUED 740 PM EDT SUN APR 14 2013/
AVIATION...
VFR EXPECTED THROUGH THE PERIOD. SE FLOW PREVAILING AT ALL
TERMINALS. FOG COULD DEVELOP TOWARDS THE MORNING ACROSS INTERIOR
AREAS...AND POSSIBLY AFFECT KAPF. FOR THAT REASON...REDUCED
VIS/CEILINGS AT THAT TERMINAL BY 15/10Z. ALL EASTERN
TERMINALS COULD SEE A BKN/OVC CLOUD DECK DEVELOPING BY
15/08Z...WITH NO OTHER CONCERNS ATTM. WILL AMEND IF NECESSARY.
PREV DISCUSSION... /ISSUED 334 PM EDT SUN APR 14 2013/
DISCUSSION...NEAR TERM TRENDS CONTINUE TO SUGGEST CONVECTION
FOCUSING FROM INTERIOR COLLIER AND POINTS NORTH TO NORTHEAST
ACROSS THE LAKE OKEECHOBEE REGION. SURFACE BASED CAPE IN THIS AREA
IS NOW AT AROUND 3000 J/KG AND WITH CONVERGENCE ALONG THE GULF SEA
BREEZE, WE STILL EXPECT TSTORM FOCUSED TO BE FROM INTERIOR COLLIER
COUNTY TO THE LAKE OKEECHOBEE REGION, WHERE ISOLATED SEVERE
TSTORMS ARE POSSIBLE, CAPABLE OF PRODUCING WINDS TO AROUND 60 MPH
AND HAIL. RIGHT NOW IT APPEARS NAPLES AND THE EAST COAST METRO
WILL STAY DRY, THOUGH HAVE KEPT SLIGHT CHANCE OF TSTORMS IN FOR
THE PALM BEACHES THROUGH THIS EVENING, AS IT IS POSSIBLE A FEW
STORMS COULD MAKE IT THAT WAY DUE TO A MORE WESTERLY STEERING FLOW
THERE.
CONVECTION WILL WANE THIS EVENING WITH TRANQUIL WEATHER OVERNIGHT.
AREAS OF FOG COULD DEVELOP DUE TO LIGHT WINDS OVERNIGHT ALONG WITH
HIGH SURFACE MOISTURE, ESPECIALLY ACROSS THE LAKE REGION, SO
PLACED THIS IN THE FORECAST FOR LATE TONIGHT.
ANOTHER SHORTWAVE OVER THE WESTERN GULF OF MEXICO IS SHOWN BY THE
GFS TO TRACK ACROSS SOUTH FL TOMORROW AFTERNOON. IT STILL LOOKS
SUFFICIENTLY MOIST AND UNSTABLE TO RESULT IN THUNDERSTORM
DEVELOPMENT DURING THE AFTERNOON ON SEA BREEZE CONVERGENCE.
THE FOCUS LOOKS TO BE OVER THE INTERIOR AS THE THINKING IS THAT
THE ATLANTIC AND GULF SEA BREEZES WILL PUSH INLAND BEFORE
DEVELOPMENT OCCURS LATE IN THE DAY. HOWEVER, STILL HAVE SLIGHT
CHANCE POPS ALONG THE COASTS. STORM MOTION TO THE EAST COULD ALLOW
ACTIVITY TO MOVE BACK TOWARDS THE EAST COAST LATE IN THE DAY, BUT
THIS IS UNCERTAIN.
DRIER AIR MOVES INTO SOUTH FL ON TUESDAY ALONG WITH A RIDGE
BUILDING UP ACROSS FLORIDA. THIS WILL RESULT IN A MAINLY DRY
WEATHER PATTERN TUE-FRI, A BREAK FROM THE ACTIVE PAST COUPLE OF
DAYS. HOWEVER, THIS BREAK WILL BE BRIEF AS THE WEATHER LOOKS TO
BECOME POTENTIALLY QUITE ACTIVE NEXT WEEKEND AS GFS AND ECMWF BOTH
CONTINUE TO SHOW A HIGHLY AMPLIFIED LONG WAVE TROUGH MOVING INTO
THE EASTERN CONUS. THIS SETS UP A SURFACE TROUGH ACROSS SOUTH FL,
AND A SLOW MOVING ONE AT THAT. SO A RATHER DRY WORK WEEK AHEAD
FOLLOWED BY A POTENTIALLY STORMY WEEKEND. I KNOW, NOT WELL TIMED!
MARINE...WINDS WILL PREVAIL OUT OF THE SOUTHEAST GENERALLY BELOW
15 KT WITH SEAS OF LESS THAN 4 FEET.
FIRE WEATHER...NO CONCERNS AS RELATIVE HUMIDITIES WILL STAY WELL
ABOVE CRITICAL LEVELS. TSTORM FOCUS THROUGH EARLY EVENING WILL BE
ACROSS THE LAKE REGION. ON MONDAY, WE EXPECT THE FOCUS TO BE
ACROSS THE ENTIRE INTERIOR, WITH A SLIGHT CHANCE TOWARDS THE
COASTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 84 72 84 / 20 30 10 10
FORT LAUDERDALE 75 86 74 84 / 10 20 10 10
MIAMI 75 87 73 86 / 10 20 10 10
NAPLES 72 88 71 88 / 10 20 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
208 AM EDT SAT APR 13 2013
.AVIATION...
OVERALL VFR CONDITIONS ARE FORECAST FOR THE NEXT 24 HOURS. HOWEVER,
PERIODS OF MVFR CEILINGS ARE POSSIBLE AROUND SHOWERS THAT WILL BE IN
THE VICINITY PARTICULAR OF TERMINALS IN MIAMI DADE THIS MORNING.
FOR THE MOMENT INCLUDED CLOUD DECKS UNDER 3 KFT GIVEN THE
UNCERTAINTY AND WILL AMEND AS NEEDED. LATER TODAY FORECAST SOUNDINGS
AND GUIDANCE IN GENERAL AGREE TSTMS WILL DEVELOP ACROSS INTERIOR
SECTIONS LIKELY AFFECTING VCNTY OF EAST COAST TERMINALS THROUGH
THE AFTERNOON AND EARLY EVENING HOURS. OUTFLOW BOUNDARIES COULD
ALSO HELP TRIGGER DEVELOPMENT CLOSE TO APF ALSO PLUS ANY ACTIVITY
MOVING IN FROM THE GULF, WHICH GIVEN UPR LEVEL TROUGH AND GULF
ACTIVITY IS VERY MUCH POSSIBLE. THEREFORE, VCSH FOR EAST COAST
TERMINALS THIS MORNING AND VCTS FOR AFTERNOON AND EVENING AS WELL
AS MENTION OF VCSH LATER THIS MORNING AND VCTS THIS AFTERNOON FOR
APF IS WARRANTED AT THIS TIME. SHOULD ANY TSTMS AFFECT ANY GIVEN
TERMINAL BRIEF PERIODS OF IFR CEILINGS AND VIS WILL BE LIKELY.
LIGHT SOUTHERLY WINDS THIS MORNING ALONG EAST COAST TERMINALS WILL
SHIFT FROM THE SE LATER TODAY AROUND 10 KNOTS. LIGHT SOUTH TO
SOUTHEAST WINDS AT APF WILL SHIFT FROM THE SW AROUND 10 KNOTS
SOMETIME AROUND NOON BEFORE BECOMING LIGHT AND VARIABLE DURING
EVENING HOURS.
&&
.PREV DISCUSSION... /ISSUED 950 PM EDT FRI APR 12 2013/
UPDATE...
THE FORECAST WAS UPDATED TO REFLECT THE DISSIPATION OF THE SHOWERS
AND THUNDERSTORMS ACROSS THE NORTHEASTERN SECTION OF PALM BEACH
COUNTY EARLIER THIS EVENING. A SLIGHT CHANCE OF SHOWERS WAS LEFT
IN THE FORECAST OVER NIGHT FOR ALL AREAS AND FOR THE OFF SHORE
GULF WATERS A SLIGHT CHANCE OF THUNDERSTORMS WAS INCLUDED.
RECENT RADAR IMAGERY INDICATES SHOWERS MOVING NORTHWARD ACROSS
THE FLORIDA STRAITS AND THE KEYS. AS THE COLD FRONT CONTINUES TO
MOVE INTO THE EASTERN GULF...THERE IS A LINE OF THUNDERSTORMS
AHEAD OF THE FRONT IN THE EASTERN GULF. THE RAPID REFRESH GUIDANCE
INDICATED THAT CONVECTION MAY REACH THE OFF SHORE GULF WATERS
AROUND 05Z WITH A SLIGHT CHANCE OF THUNDERSTORMS MENTIONED IN THE
FORECAST.
OTHERWISE...FORECAST IS ON TRACK FOR SATURDAY WITH SCATTERED
SHOWERS AND THUNDERSTORMS EXPECTED ACROSS THE REGION IN THE
AFTERNOON AND EARLY EVENING.
60
PREV DISCUSSION... /ISSUED 734 PM EDT FRI APR 12 2013/
AVIATION...
THE THUNDERSTORMS OVER THE PALM BEACH COUNTY AREA SHOULD
DISSIPATE BY 9 PM EDT THIS EVENING LEAVING ONLY SOME SHOWERS UNTIL
11 PM EDT. SO WILL CONTINUE THE VCTS FOR KPBI UNTIL 01Z AND THEN
VCSH UNTIL 03Z TONIGHT. REST OF THE TAF SITES ACROSS SOUTH FLORIDA
SHOULD REMAIN DRY TONIGHT. THE SHOWERS WILL COME BACK INTO PLAY AT
ALL OF THE TAF SITES BETWEEN 12Z AND 16Z ON SATURDAY...BEFORE
THUNDERSTORMS DEVELOP FOR THE AFTERNOON HOURS ON SATURDAY. SO WILL
HAVE A VCSH FROM 12Z UNTIL 16Z AND THEN VCTS AFTER 16Z SATURDAY
FOR ALL TAF SITES OVER SOUTH FLORIDA.
THE WIND SPEEDS TONIGHT AT ALL OF THE TAF SITES WILL DECREASE FROM
5 TO 10 KNOTS THIS EVENING TO LESS THAN 5 KNOTS AFTER 03Z MAINLY
FROM THE SOUTH TO SOUTHWEST DIRECTION. THE ONLY EXCEPTION TO THIS
IS AT KAPF WHERE THE WINDS WILL BE FROM THE SOUTHEAST DIRECTION.
THE WINDS WILL THEN INCREASE ON SATURDAY MORNING TO AROUND 10
KNOTS FROM THE SOUTHEAST...WITH KAPF TAF SITE SWINGING TO A
SOUTHWEST DIRECTION AFTER 16Z SATURDAY.
THE VIS SHOULD REMAIN IN THE VFR CONDITIONS TONIGHT INTO SATURDAY
AT ALL OF THE TAF SITES...EXCEPT FOR KPBI...KFLL...KFXE...AND KAPF
TAF SITES WITH THE CEILING TO FALL DOWN INTO THE MVFR CONDITIONS
BETWEEN 10Z AND 13Z TONIGHT. THE REASON FOR THIS IS FOR POSSIBLE
FOG DEVELOP OVER THE INTERIOR AREAS THAT COULD WORK INTO THESE TAF
SITES.
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 230 PM EDT FRI APR 12 2013/
SHORT TERM (TONIGHT-SUNDAY NIGHT)...
RECENTLY ANIMATED WATER VAPOR LOOP SHOWED PLENTY OF MID/UPPER
MOISTURE SPREADING NORTHEAST ACROSS THE FLORIDA PENINSULA WITHIN THE
SOUTHWEST UPPER FLOW AND A WEAK RIDGE AXIS EXTENDING NORTH OVER THE
BAHAMAS. THE LATEST SURFACE ANALYSIS SHOWED A COLD FRONT EXTENDING
SOUTH AND SOUTHWEST ACROSS THE FLORIDA BIG BEND TO THE CENTRAL GULF
OF MEXICO WITH MOIST SOUTHERLY FLOW ACROSS THE FLORIDA PENINSULA
AHEAD OF IT. THE LATEST SHORT-RANGE FORECAST GUIDANCE REMAINS IN
GOOD AGREEMENT AND SHOWS THIS FRONTAL BOUNDARY CONTINUING EASTWARD
TOWARD AND INTO CENTRAL FLORIDA LATER THIS EVENING THROUGH TONIGHT
BEFORE STALLING AROUND OR JUST NORTH OF THE LAKE THROUGH THE DAY
SATURDAY. PLENTY OF DEEP LAYER MOISTURE AND SOUTHWEST DEEP LAYER
FLOW COMBINED WITH DAYTIME HEATING AND AFTERNOON SEA BREEZES WILL
SUPPORT SCATTERED SHOWERS AND STORMS THROUGH SATURDAY.
FOR THE REMAINDER OF THE AFTERNOON AND EVENING TODAY...THE BEST
CHANCE FOR THESE STORMS WILL REMAIN OVER THE NORTHERN AND EASTERN
SECTIONS OF THE AREA...ESPECIALLY OVER PALM BEACH/BROWARD COUNTIES.
THE LATEST HRRR MODEL REFLECTIVITIES LINE UP WELL WITH THE CURRENT
TRENDS AND INDICATE THE AFTERNOON CONVECTION BECOMING CONCENTRATED
OVER THE EAST COAST METRO AND COASTAL LOCATIONS FROM BROWARD TO PALM
BEACH COUNTIES THROUGH SUNSET...THEN TRENDING DOWN THROUGH
MID/LATE-EVENING PERIODS. CONSIDERING THE MOIST PROFILES IN
PLACE...THE MAIN IMPACTS WITH THESE STORMS TODAY WILL BE WET
MICROBURSTS AND HEAVY RAINFALL. ADDITIONALLY...LOCALIZED FLOODING
CAN`T BE RULED OUT IN THE AREAS WHERE THIS ACTIVITY SETS UP.
ON SATURDAY...ANOTHER POTENTIALLY ACTIVE DAY IS ANTICIPATED DUE TO A
COMBINATION OF DEEP LAYER MOISTURE...DAYTIME HEATING/INSTABILITY AND
THE FRONTAL BOUNDARY IN THE VICINITY OF THE AREA. THIS BOUNDARY
ALONG WITH THE AFTERNOON SEA BREEZE WILL BE THE FOCUS AREAS FOR
AFTERNOON CONVECTION. THE LATEST MODEL GUIDANCE DOES INDICATE MORE
OF A SOUTHERLY FLOW UP TO 700MB THROUGH THIS PERIOD TOMORROW...WHICH
MAY RESULT IN THE AFTERNOON ACTIVITY BECOMING CONCENTRATED GENERALLY
OVER THE NORTHERN 1/3 OF THE FORECAST AREA OR AROUND THE LAKE
REGION. SATURDAY NIGHT THROUGH SUNDAY NIGHT...THIS BOUNDARY WILL
CONTINUE TO DIMINISH AND BEGIN TO LIFT BACK TO THE NORTH AS A
SHORTWAVE TROUGH LIFTS NORTHEAST OVER THE CENTRAL GULF COAST REGION.
SOUTHEAST LOW-LEVEL FLOW WILL BE EXPECTED SUNDAY WITH THE BEST
CHANCE OF AFTERNOON SHOWERS/STORMS OVER THE NWRN 1/3 OF THE FORECAST
AREA OR FROM NAPLES TO THE LAKE.
LONG TERM (MONDAY-FRIDAY)...
MOSTLY QUIET WEATHER CONDITIONS WILL BE EXPECTED AS DEEP LAYER
RIDGING REMAINS AS THE DOMINANT SYNOPTIC FEATURE THROUGH THE
MID-WEEK TIME FRAME. LATER IN THE WEEK...THE MODELS REMAIN IN DECENT
AGREEMENT...OUTSIDE OF SOME MINOR TIMING DIFFERENCES...AND GENERALLY
SHOW ANOTHER FRONTAL BOUNDARY APPROACHING AND MOVING OVER THE STATE.
IF THE MODELS REMAIN PERSISTENT WITH THIS FEATURE OVER THE WEEKEND
AND INTO THE UPCOMING WEEK...EXPECT THE EXTENDED RANGE RAINFALL
CHANCES TO STEADILY INCREASE AS CONFIDENCE RISES. OTHERWISE...QUIET
CONDITIONS WILL CONTINUE THROUGH THE WEEK WITH TEMPERATURES
REMAINING ABOVE NORMAL WITH THE MOIST SOUTHERLY FLOW IN PLACE. THE
BEST CHANCE FOR AFTERNOON SHOWERS OR STORMS WILL REMAIN INLAND FROM
NAPLES TO THE LAKE.
MARINE...
MODERATE SOUTHERLY WINDS WILL PERSIST INTO THE WEEKEND AS A COLD
FRONT APPROACHES AND STALLS JUST NORTH OF THE SOUTH FLORIDA WATERS
SATURDAY. SCATTERED SHOWERS AND A FEW STORMS WILL BE EXPECTED
THROUGH SATURDAY AS THE FRONT APPROACHES AND STALLS JUST NORTH OF
THE AREA. THIS FRONTAL BOUNDARY WILL DIMINISH OVER THE WEEKEND AND
INTO THE UPCOMING WEEK WITH HIGH PRESSURE EXPECTED TO BUILD BACK
OVER THE AREA NEXT WEEK.
FIRE WEATHER...
PLENTY OF MOISTURE ALONG WITH INCREASING RAIN CHANCES WILL PRECLUDE
ANY CHANCE FOR CRITICAL FIRE WEATHER CONDITIONS THROUGH THE WEEKEND
AS A COLD FRONT APPROACHES AND STALLS AROUND THE LAKE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 84 71 83 74 / 50 20 20 10
FORT LAUDERDALE 85 73 84 75 / 50 20 20 10
MIAMI 86 72 84 75 / 40 20 20 10
NAPLES 83 70 86 70 / 40 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...52/PS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
923 PM EDT SUN APR 14 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM WILL TRACK FROM THE NORTHERN GULF OF MEXICO
TO THE SOUTHEAST COAST TONIGHT INTO EARLY MONDAY...THEN WILL PULL
AWAY FROM THE REGION AND WEAKEN MONDAY AS HIGH PRESSURE CONTINUES
TO RIDGE INTO THE FORECAST AREA. HIGH PRESSURE WILL GRADUALLY
STRENGTHEN OVER THE WESTERN ATLANTIC TUESDAY THROUGH FRIDAY BEFORE
A COLD FRONT MOVES IN FRIDAY NIGHT. HIGH PRESSURE WILL BUILD INTO
THE REGION NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
MADE MINOR TIMING ADJUSTMENTS PER GOING RADAR TRENDS. WATCHING A
SEVERE LINE SEGMENT MOVING NE OUT OF FAR SOUTHERN GA. THIS FEATURE
IS LIKELY BEING SUPPORTED BY INTENSE FORCING ASSOCIATED WITH THE
LEADING EDGE OF A MESOHIGH THAT FORMED IN THE WAKE OF AN EARLIER
SQUALL LINE. SVR TSTM WRNG MAY BE NEED FOR LONG-MCINTOSH COUNTIES
WITHIN THE HOUR. SPECIAL MARINE WRNGS MAY ALSO BE NEEDED.
FARTHER WEST...HIGH WINDS ASSOC WITH A WAKE LOW ARE MOVING RAPIDLY
E ACROSS CNTRL GA. THESE WNDS HAVE CAUSED DAMAGED IN A FEW LOCALES
PER REPORTS FROM WFO ATLANTA. WINDS AT DUBIN AND EASTMAN SUGGEST
SPEEDS MAY BE DIMINISHING AT BIT AS THE LOW FILLS. WILL HOLD WIND
GUSTS AT 35 MPH FOR NOW...BUT A WIND ADV MAY BE NEEDED FOR 2-3
HOUR ACROSS THE WRN ZONES.
UPDATED GRIDS/TXT PRODUCTS HAVE BEEN ISSUED.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
MONDAY AND MONDAY NIGHT...THE PERIOD WILL START OUT WITH THE POTENT
500 MB SHORTWAVE PUSHING OUT OVER THE WESTERN ATLANTIC AS THE
SURFACE LOW PASSES BY RIGHT ALONG THE SC COASTLINE. ANY LINGERING
SHOWER/THUNDERSTORM ACTIVITY SHOULD BE LIMITED TO THE NORTHEAST
CORNER OF THE FORECAST AREA AND BE ON A DIMINISHING TREND AS MID
LEVEL LAPSE RATES WEAKEN. THE REMAINDER OF THE DAY WILL SEE LOW
STRATUS ACROSS MUCH OF THE AREA...ERODING FROM SOUTHWEST TO
NORTHEAST THROUGH THE AFTERNOON. WE MAY SEE ADDITIONAL SHOWERS...BUT
POPS HAVE BEEN LIMITED TO SLIGHT CHANCE FOR MUCH OF THE DAY AND
EVENTUALLY THE FORECAST GOES DRY BY LATE AFTERNOON. THE STUBBORN
CLOUDS WILL HAVE THE GREATEST AFFECT ON TEMPERATURES. AREAS ACROSS
SOUTHEAST GA WILL LIKELY SCATTER OUT SOONEST AND SEE THE QUICKEST
WARM UP INTO THE UPPER 70S TO NEAR 80. THE TRI-COUNTY WILL BE THE
COOLEST WHERE THE CLOUDS HANG ON THE LONGEST AND WILL TOP OUT IN THE
MID 70S. OVERNIGHT...THE PRIMARY FORECAST PROBLEM WILL BE THE
POTENTIAL FOR LOW STRATUS AND FOG DEVELOPMENT. WITH CONSIDERABLE LOW
LEVEL MOISTURE BEING TRAPPED BENEATH THE NOCTURNAL INVERSION AND
DRYING IN THE MID/UPPER LEVELS...SHOULD BE GOOD FOG CONDITIONS. ONE
SLIGHT LIMITING FACTOR MAY BE ENOUGH LINGERING LOW LEVEL FLOW.
EXPECT A MILD NIGHT WITH LOWS FALLING THE LOW 60S/NEAR 60.
TUESDAY THROUGH WEDNESDAY...UPPER RIDGING ALOFT WILL BUILD IN AS THE
AREA STAYS UNDER THE INFLUENCE OF ATLANTIC HIGH PRESSURE AT THE
SURFACE. WE WILL LIKELY CONTINUE TO SEE A GOOD AMOUNT OF CLOUD COVER
TUESDAY WITH LINGERING LOW LEVEL MOISTURE. SOME MODELS CONTINUE TO
DEVELOP ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS THE FAR
WESTERN ZONES EACH DAY...BUT A PERUSAL OF MODEL SOUNDINGS SHOWS A
CONSIDERABLE SUBSIDENCE INVERSION UNDER THE RIDGE ALOFT. HAVE KEPT
THE FORECAST DRY TUESDAY BUT CONTINUED THE SMALL SLIVER OF SLIGHT
CHANCES FAR TO THE WEST ON WEDNESDAY DUE TO BETTER SURFACE HEATING.
TEMPS WILL RISE A COUPLE OF DEGREES EACH DAY...TOPPING OUT IN THE
LOW 80S BY WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE UPPER RIDGE WILL HANG ON FOR ONE MORE DAY BEFORE A LARGE SCALE
PATTERN SHIFT OCCURS. A PRONOUNCED LONGWAVE TROUGH WILL SPREAD
ACROSS PRETTY MUCH THE ENTIRE CONTIGUOUS UNITED STATES FRIDAY
THROUGH SUNDAY. A STRONG COLD FRONT WILL SWEEP THROUGH THE AREA
FRIDAY NIGHT WITH DRY CANADIAN HIGH PRESSURE BUILDING IN ITS WAKE.
WE EXPECT DECENT COVERAGE OF SHOWERS AND THUNDERSTORMS FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT...THEN DRIER AND MUCH COOLER WEATHER
FOR THE WEEKEND. HIGHS ON SATURDAY COULD STRUGGLE TO REACH 70
DEGREES AND SATURDAY NIGHT WE COULD SEE SOME UPPER 40S IN SPOTS.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
RA WL OVRSPRD THE TERMINALS THIS EVNG AS LOW PRES REDVLPS OFF THE
SC/GA COAST. THE RISK FOR TSTMS IS INCRG PER GOING LIGHTING DATA
AND RAP INSTABILITY PROFILES. GENERALLY EXPECT IFR/MVFR CONDITIONS
TO DOMINATE THIS EVENING WITHIN THE RAIN WITH LOCALIZED PERIODS OF
LIFR PSBL IN TSTMS...ESP AT KSAV. THE RAIN IS XPCTD TO DEPART KSAV
ROUGHLY BY 04Z AND 07Z AT KCHS...PLUS OR MINUS AN HOUR OR SO.
GUIDANCE IS SIMILAR ON SHOWING LOW STATUS FILLING IN ERLY MON WITH
CIGS DROPPING AS LOW AS LIFR PRIOR TO SUNRISE. CIGS WILL BE SLOW
TO LIFT MON MRNG...BUT ANTICIPATE CONDITIONS RETURNING TO MVFR BY
LATE MRNG/ERLY AFTN.
EXTENDED AVIATION OUTLOOK...MORE SUB VFR CEILINGS AND VISIBILITIES
EXPECTED MONDAY NIGHT AND THEN LESSER CHANCES TUESDAY NIGHT.
&&
.MARINE...
A TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN A RIDGE OF HIGH
PRESSURE CENTERED N/W OF THE WATERS AND A SURFACE WAVE OF LOW
PRESSURE EJECTING ENE FROM THE GULF OF MEXICO WILL SUPPORT
INCREASING ONSHORE FLOW AND BUILDING SEAS THIS EVENING. THEN...
WINDS WILL SHIFT TOWARD THE S/SW AS THE SURFACE LOW PUSHES INTO
THE WATERS OVERNIGHT. HOWEVER...FORECAST CONFIDENCE REMAINS
RATHER LOW DUE TO A WEAKER THAN EXPECTED GRADIENT LATE SUNDAY
AFTERNOON...AN UNCERTAIN GRADIENT RESPONSE AS THE SURFACE LOW
APPROACHES FROM THE NORTHERN GULF TONIGHT AND UNCERTAINTY
REGARDING THE EXACT TRACK OF THE SURFACE LOW. RAISED A SMALL CRAFT
ADVISORY FOR THE GA WATERS BEYOND 20 NM TO ACCOUNT FOR AN ELEVATED
POTENTIAL FOR GUSTS TO 25 KT AND 6 FT SEAS TONIGHT...AND CAPPED
WINDS AT 15-20 KT AND SEAS AT 3-5 FT ELSEWHERE. HOWEVER...GRADIENTS
COULD BECOME TIGHTER THAN EXPECTED SUPPORTING HIGHER WINDS/LARGER
SEAS THAN CURRENTLY FORECAST ACROSS NEARSHORE WATERS TONIGHT.
MONDAY THROUGH FRIDAY...THE LOCAL WATERS WILL BE UNDER THE INFLUENCE
OF ATLANTIC HIGH PRESSURE AND MODERATE ONSHORE FLOW THROUGH MUCH OF
THE WEEK. EXPECT DECENT A DECENT SEABREEZE EACH AFTERNOON ALONG AND
COAST AS LAND AREAS WARM. WINDS WILL BECOME SOUTHERLY THURSDAY NIGHT
AND FRIDAY AHEAD OF A COLD FRONT. SMALL CRAFT ADVISORY WINDS/SEAS
MAY DEVELOP AHEAD OF THE FRONT...THEN PERSIST IN ITS WAKE ON
SATURDAY AS WINDS SHIFT TO NNE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT MONDAY FOR AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
735 PM EDT SUN APR 14 2013
.SYNOPSIS...
LOW PRESSURE SYSTEM WILL TRACK FROM THE NORTHERN GULF OF MEXICO
TO THE SOUTHEAST COAST TONIGHT INTO EARLY MONDAY...THEN WILL PULL
AWAY FROM THE REGION AND WEAKEN MONDAY AS HIGH PRESSURE CONTINUES
TO RIDGE INTO THE FORECAST AREA. HIGH PRESSURE WILL GRADUALLY
STRENGTHEN OVER THE WESTERN ATLANTIC TUESDAY THROUGH FRIDAY BEFORE
A COLD FRONT MOVES IN FRIDAY NIGHT. HIGH PRESSURE WILL BUILD INTO
THE REGION NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
WDSPRD RAINS ARE STEADILY DVLPG ACROSS NRN FL AND SW GA WITHIN A
CORRIDOR OF STRONG LIFT BEING GENERATED BY A POTENT SRN STREAM
SHORTWAVE AND A WELL PRONOUNCED COUPLED JET STRUCTURE. LGT RAINS
AFFECTING MUCH OF SRN SC AND SE GA WILL GIVE WAY TO HEAVIER
CONVECTIVE RNFL OVR THE NXT FEW HRS AS THE AXIS OF STRONGEST
FORCING OVRSPRDS THE RGN. HIGH PWATS NEARING 1.8 INCHES COUPLED
WITH SOME SFC AND ELEVATED INSTABILITY WILL SUPPORT LOCALLY HVY
RAINS AT TIMES...ESP S OF I-16 AND ALONG THE SRN SC COASTAL
COUNTIES WHERE LOCALIZED RNFL AMOUNTS COULD APRCH 2-3 INCHES.
14/22Z SFC ANALYSIS SHOWED LOW PRES OVR APALACHEE BAY WITH A WMFNT
XTNDG E ACROSS NRN FL. SECONDARY CYCLOGENESIS IS XPCTD TO OCCUR
OFF THE GA/SC COAST OVR THE NXT FEW HRS AS THE APRCHG SHORTWAVE
BEGINS TO INTERACT WITH THE HIGHER BAROCLINICITY ALONG THE WRN
WALL OF THE GULF STREAM. IN FACT...SURFACE PRESSURES WERE ALREADY
FALLING RAPIDLY AT MANY OF THE COASTAL OBSERVATION SITES WITHIN
THE LAST HR. THE WMFNT MAY ARCH WESTWARD CLOSER TO THE BEACHES LTR
THIS EVNG AS SECONDARY LOW PRES FORMS...BUT THE WARM SECTOR AND
BTR SVR WX PROBS LOOK TO REMAIN OFFSHORE ATTM. SHOULD THE LOW
TRACK CLOSER OR JUST INLAND FROM THE COAST...THE RISK FOR LCLLY
DMGG WNDS AND ISOLD TORNADOES WOULD INCR OVR THE COASTAL ZONES.
CATEGORICAL POPS NEAR 100 PCNT LOOK ON TRACK FOR ALL ZONES
OVRNGT WITH THE HEAVIEST RAINS LIKELY OCCUR THIS EVNG OVER SE GA
AND LATE EVNG/ERLY MON MRNG OVER SE SC. IMPRESSIVE SHOWALTER
VALUES NEARING -4C AT TIMES WILL SUPPORT A RISK FOR SCT-NMRS
TSTMS SO WILL HIGHTLIGHT THIS IN THE GRIDDED AND TXT FCSTS FOR THE
ERLY EVNG UPDATE. LOWS IN THE LWR-MID 60S LOOK FINE...ALTHOUGH
HRLY TEMPS WILL BE A TOUGH CALL AS RAIN OVRSPRDS FROM THE SW.
OF NOTE...IT APPEARS A WEAK WAKE LOW IS FORMING ACROSS SW GEORGIA
IN THE WAKE OF ONGOING CONVECTION AND THE ASSOCIATED MESO HIGH
OVER N FL. REPORTS OF WIND GUSTS NEAR 45 KT HAVE BEEN REPORTED
WITH THIS FEATURE. H3R DOES SHOW SOME SORT OF WAKE LOW FEATURE
MOVING ACROSS S GA THIS EVNG... SO THIS WILL HAVE TO BE WATCHED
CAREFULLY.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
MONDAY AND MONDAY NIGHT...THE PERIOD WILL START OUT WITH THE POTENT
500 MB SHORTWAVE PUSHING OUT OVER THE WESTERN ATLANTIC AS THE
SURFACE LOW PASSES BY RIGHT ALONG THE SC COASTLINE. ANY LINGERING
SHOWER/THUNDERSTORM ACTIVITY SHOULD BE LIMITED TO THE NORTHEAST
CORNER OF THE FORECAST AREA AND BE ON A DIMINISHING TREND AS MID
LEVEL LAPSE RATES WEAKEN. THE REMAINDER OF THE DAY WILL SEE LOW
STRATUS ACROSS MUCH OF THE AREA...ERODING FROM SOUTHWEST TO
NORTHEAST THROUGH THE AFTERNOON. WE MAY SEE ADDITIONAL SHOWERS...BUT
POPS HAVE BEEN LIMITED TO SLIGHT CHANCE FOR MUCH OF THE DAY AND
EVENTUALLY THE FORECAST GOES DRY BY LATE AFTERNOON. THE STUBBORN
CLOUDS WILL HAVE THE GREATEST AFFECT ON TEMPERATURES. AREAS ACROSS
SOUTHEAST GA WILL LIKELY SCATTER OUT SOONEST AND SEE THE QUICKEST
WARM UP INTO THE UPPER 70S TO NEAR 80. THE TRI-COUNTY WILL BE THE
COOLEST WHERE THE CLOUDS HANG ON THE LONGEST AND WILL TOP OUT IN THE
MID 70S. OVERNIGHT...THE PRIMARY FORECAST PROBLEM WILL BE THE
POTENTIAL FOR LOW STRATUS AND FOG DEVELOPMENT. WITH CONSIDERABLE LOW
LEVEL MOISTURE BEING TRAPPED BENEATH THE NOCTURNAL INVERSION AND
DRYING IN THE MID/UPPER LEVELS...SHOULD BE GOOD FOG CONDITIONS. ONE
SLIGHT LIMITING FACTOR MAY BE ENOUGH LINGERING LOW LEVEL FLOW.
EXPECT A MILD NIGHT WITH LOWS FALLING THE LOW 60S/NEAR 60.
TUESDAY THROUGH WEDNESDAY...UPPER RIDGING ALOFT WILL BUILD IN AS THE
AREA STAYS UNDER THE INFLUENCE OF ATLANTIC HIGH PRESSURE AT THE
SURFACE. WE WILL LIKELY CONTINUE TO SEE A GOOD AMOUNT OF CLOUD COVER
TUESDAY WITH LINGERING LOW LEVEL MOISTURE. SOME MODELS CONTINUE TO
DEVELOP ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS THE FAR
WESTERN ZONES EACH DAY...BUT A PERUSAL OF MODEL SOUNDINGS SHOWS A
CONSIDERABLE SUBSIDENCE INVERSION UNDER THE RIDGE ALOFT. HAVE KEPT
THE FORECAST DRY TUESDAY BUT CONTINUED THE SMALL SLIVER OF SLIGHT
CHANCES FAR TO THE WEST ON WEDNESDAY DUE TO BETTER SURFACE HEATING.
TEMPS WILL RISE A COUPLE OF DEGREES EACH DAY...TOPPING OUT IN THE
LOW 80S BY WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE UPPER RIDGE WILL HANG ON FOR ONE MORE DAY BEFORE A LARGE SCALE
PATTERN SHIFT OCCURS. A PRONOUNCED LONGWAVE TROUGH WILL SPREAD
ACROSS PRETTY MUCH THE ENTIRE CONTIGUOUS UNITED STATES FRIDAY
THROUGH SUNDAY. A STRONG COLD FRONT WILL SWEEP THROUGH THE AREA
FRIDAY NIGHT WITH DRY CANADIAN HIGH PRESSURE BUILDING IN ITS WAKE.
WE EXPECT DECENT COVERAGE OF SHOWERS AND THUNDERSTORMS FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT...THEN DRIER AND MUCH COOLER WEATHER
FOR THE WEEKEND. HIGHS ON SATURDAY COULD STRUGGLE TO REACH 70
DEGREES AND SATURDAY NIGHT WE COULD SEE SOME UPPER 40S IN SPOTS.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
RA WL OVRSPRD THE TERMINALS THIS EVNG AS LOW PRES REDVLPS OFF THE
SC/GA COAST. THE RISK FOR TSTMS IS INCRG PER GOING LIGHTING DATA
AND RAP INSTABILITY PROFILES. GENERALLY EXPECT IFR/MVFR CONDITIONS
TO DOMINATE THIS EVENING WITHIN THE RAIN WITH LOCALIZED PERIODS OF
LIFR PSBL IN TSTMS...ESP AT KSAV. THE RAIN IS XPCTD TO DEPART KSAV
ROUGHLY BY 04Z AND 07Z AT KCHS...PLUS OR MINUS AN HOUR OR SO.
GUIDANCE IS SIMILAR ON SHOWING LOW STATUS FILLING IN ERLY MON WITH
CIGS DROPPING AS LOW AS LIFR PRIOR TO SUNRISE. CIGS WILL BE SLOW
TO LIFT MON MRNG...BUT ANTICIPATE CONDITIONS RETURNING TO MVFR BY
LATE MRNG/ERLY AFTN.
EXTENDED AVIATION OUTLOOK...MORE SUB VFR CEILINGS AND VISIBILITIES
EXPECTED MONDAY NIGHT AND THEN LESSER CHANCES TUESDAY NIGHT.
&&
.MARINE...
A TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN A RIDGE OF HIGH
PRESSURE CENTERED N/W OF THE WATERS AND A SURFACE WAVE OF LOW
PRESSURE EJECTING ENE FROM THE GULF OF MEXICO WILL SUPPORT
INCREASING ONSHORE FLOW AND BUILDING SEAS THIS EVENING. THEN...
WINDS WILL SHIFT TOWARD THE S/SW AS THE SURFACE LOW PUSHES INTO
THE WATERS OVERNIGHT. HOWEVER...FORECAST CONFIDENCE REMAINS
RATHER LOW DUE TO A WEAKER THAN EXPECTED GRADIENT LATE SUNDAY
AFTERNOON...AN UNCERTAIN GRADIENT RESPONSE AS THE SURFACE LOW
APPROACHES FROM THE NORTHERN GULF TONIGHT AND UNCERTAINTY
REGARDING THE EXACT TRACK OF THE SURFACE LOW. RAISED A SMALL CRAFT
ADVISORY FOR THE GA WATERS BEYOND 20 NM TO ACCOUNT FOR AN ELEVATED
POTENTIAL FOR GUSTS TO 25 KT AND 6 FT SEAS TONIGHT...AND CAPPED
WINDS AT 15-20 KT AND SEAS AT 3-5 FT ELSEWHERE. HOWEVER...GRADIENTS
COULD BECOME TIGHTER THAN EXPECTED SUPPORTING HIGHER WINDS/LARGER
SEAS THAN CURRENTLY FORECAST ACROSS NEARSHORE WATERS TONIGHT.
MONDAY THROUGH FRIDAY...THE LOCAL WATERS WILL BE UNDER THE INFLUENCE
OF ATLANTIC HIGH PRESSURE AND MODERATE ONSHORE FLOW THROUGH MUCH OF
THE WEEK. EXPECT DECENT A DECENT SEABREEZE EACH AFTERNOON ALONG AND
COAST AS LAND AREAS WARM. WINDS WILL BECOME SOUTHERLY THURSDAY NIGHT
AND FRIDAY AHEAD OF A COLD FRONT. SMALL CRAFT ADVISORY WINDS/SEAS
MAY DEVELOP AHEAD OF THE FRONT...THEN PERSIST IN ITS WAKE ON
SATURDAY AS WINDS SHIFT TO NNE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT MONDAY FOR AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1257 PM MDT SAT APR 13 2013
.UPDATE...
ISSUED AT 838 AM MDT SAT APR 13 2013
DENSE FOG CONTINUES ALONG AND JUST TO THE NORTH OF THE REPUBLICAN
RIVER VALLEY WITH MCK REPORTING LESS THAN A QUARTER MILE
VISIBILITIES. LOOKS LIKE THIS IS CONFINED TO NORTHERN RED WILLOW
AND NORTHEAST HITCHCOCK COUNTY...AND HAVE EXPANDED THE ADVISORY
FOR ANOTHER HOURS. GIVEN THE SMALL SCALE NATURE OF IT...SHOULD
BEGIN TO CLEAR OUT QUICKLY.
UPDATE ISSUED AT 608 AM MDT SAT APR 13 2013
UPDATED FOR A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 440 AM MDT SAT APR 13 2013
FORECAST CONCERNS WILL BE CHANCES OF PRECIPITATION INTO THE
BEGINNING OF NEXT WEEK...FIRE WEATHER CONCERNS TODAY...AND WINDS
TODAY/TONIGHT. SATELLITE SHOWING AN AMPLIFIED AND BLOCKY PATTERN
FROM THE PACIFIC ACROSS NORTH AMERICA INTO THE ATLANTIC. CONTINUES TO
SHOW AN AMPLIFIED AND BLOCKY PATTERN FROM THE PACIFIC INTO EASTERN
NORTH AMERICA. VERY STRONG AND COLD SYSTEM IS DIGGING INTO SOUTHWEST
CANADA AND THE PACIFIC NORTHWEST. CURRENTLY WEST NORTHWEST TO
NORTHWEST RESIDES OVER THE REGION.
AT JET LEVEL...THE MODELS TENDED TO NOT HAVE THE JET AXIS THAT IS
PUNCHING INTO THE PACIFIC NORTHWEST TOO FAR NORTH AND EAST. THE NAM
AND GFS WERE DOING BEST ON THIS SEGMENT. THE MODELS TENDED TO HAVE
THE HEIGHT FIELD TOO FAR SOUTH AND EAST. OVERALL THE GFS...UKMET
AND CANADIAN WERE DOING THE BEST. THE RUC AND ECMWF WERE DOING
SLIGHTLY BETTER THAN THE NAM ON THE SURFACE WIND AND PRESSURE
FIELD. GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE NAM ON
THE LOW LEVEL THERMAL FIELD.
PER THE INITIAL ANALYSIS AND THE PATTERN WE ARE IN...CHOSE THE
MID/UPPER LEVEL SOLUTIONS THAT WERE FURTHER SOUTH AND FASTER
INITIALLY FOLLOWED BY BEING FURTHER SOUTH AND WEST WITH THE INCOMING
LATER.
TODAY/TONIGHT...FIRST WHAT TO DO WITH THE FOG. MODELS...EVEN
MESOSCALE...HAVING DIFFICULTY GRABBING ONTO THE FOG. WHAT IS
COMPLICATING THINGS IS A CLOUD DECK ABOVE THIS THAT HAS BEEN CAUSING
VARIABILITY IN THE FOG FIELD. BASED ON LATEST TRENDS...CHOSE TO GO
AREAS OF FOG IN THE NORTHERN AND WESTERN SECTIONS AND PATCHY
ELSEWHERE. AS THE SUN COMES UP AND THE WINDS BEGIN TO INCREASE...
THE FOG SHOULD BURN OFF.
CROSS MOUNTAIN FLOW WILL CAUSE LEE TROUGH TO DEVELOP RAPIDLY. 3 HOUR
PRESSURE FALLS AND GRADIENT WOULD INDICATE AT LEAST BREEZY POSSIBLY
A LITTLE HIGHER CONDITIONS. THIS WILL HAVE AN AFFECT ON THE FIRE
WEATHER CONDITIONS. REFER TO THAT BELOW. GUIDANCE HAS BEEN COOL THE
LAST FEW DAYS AND NOT BY A LITTLE BIT...EVEN WITH CLOUDS AROUND. SO
TOOK THE WARMEST BIAS AND ADJUSTED IT WITH SOME BIAS/CHANGE IN
FORECAST 850 MB TEMPERATURE TO ARRIVE AT THE HIGHS.
MAIN JET AXIS STAYS NORTH AND WEST OF THE AREA. ALSO MAIN MID LEVEL
AND PV ANOMALY ARE STILL NORTH OF THE AREA. ALSO SOUNDINGS HAVE TOO
MUCH OF A DRY LAYER. THERE IS SOME SURFACE BASED INSTABILITY IN THE
AFTERNOON BUT THAT IS CAPPED. THERE IS NO ELEVATED INSTABILITY PLUS
IT IS CAPPED AS WELL EVEN IF THERE WAS ANY. SO WILL KEEP THIS
PERIOD DRY. HOWEVER...SOME KIND OF PRECIPITATION COULD GET CLOSE TO
THE FAR NORTHERN SECTION. CLOUD COVER AND WESTERLY WINDS/WARM AIR
ADVECTION IN ADVANCE OF THE COLD FRONT THAT ARRIVES LATER TONIGHT
WILL KEEP THE MINS RATHER MILD. THEY MAY NOT BE WARM ENOUGH. RATHER
SUNDAY/SUNDAY NIGHT...RATHER STRONG 3 HOUR PRESSURE RISE WILL CAUSE
BREEZY TO WINDY CONDITIONS BEHIND THE FRONT IN THE MORNING. LEFT
FRONT QUADRANT OF STRONG JET BEGINS TO AFFECT THE AREA AT THE
BEGINNING OF THE DAY AND THEN STARTS GRADUALLY LIFTING TO THE NORTH
AT THE END OF THE DAY. MID LEVEL COLD AIR ADVECTION/BAROCLINIC ZONE
ALONG WITH RATHER STRONG PV ANOMALY PUSHES ACROSS THE AREA AT THE
SAME WITH THE BEST LIFT AND MOISTURE OVER THE NORTHERN PORTION OF THE
AREA. SO EXPANDED POPS THROUGH THE DAY WITH THE HIGHEST IN THE
NORTHERN PORTION. COMBINATION OF CLOUD COVER/PRECIPITATION AND COLD
AIR ADVECTION WILL TEMPERATURES FROM RISING TOO MUCH AND WENT A
LITTLE BELOW GUIDANCE.
RIGHT REAR QUADRANT IS OVER THE AREA DURING THE NIGHT AND GETS
BETTER AS THE NIGHT WHERES ON AND AS THE MID LEVEL BAROCLINIC ZONE
REMAINS OVER THE AREA. PLUS ANOTHER SHORTWAVE TROUGH APPROACHES BY
LATER IN THE NIGHT. CURRENT FORECAST CAPTURES THIS SCENARIO NICELY
AND DID NOT CHANGE IT WITH GREATEST CHANCE OF PRECIPITATION
WILL BE IN THE NORTH WITH A CHANGEOVER OR MIXTURE OF PHASE EXPECTED
IN THE WEST.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF JET/JET AXIS REMAINS
OVER OR NEAR THE NORTHWEST HALF OF THE AREA THROUGH THE PERIOD.
LOW LEVEL UPSLOPE INCREASES THROUGH THE DAY AS STRONG MID LEVEL
SOUTHWEST FLOW ALOFT CAUSES LEE TROUGH TO STRENGTHEN. ALSO A COUPLE
OF SHORTWAVE TROUGHS MOVE THROUGH IN THIS FLOW. ALMOST EVERY
PARAMETER OF THE FORECAST FOR THIS PERIOD WILL BE PROBLEMATIC.
BECAUSE OF THE PROXIMITY OF THE JET AND MID LEVEL LIFT...KEPT THE
HIGHEST POPS IN THAT SECTION. HOWEVER...THERE IS A SHARP CUTOFF
BETWEEN A LOT OF CLOUDS/NO CLOUDS AND PRECIPITATION/NO
PRECIPITATION. SO ANY SUBTLE SHIFT NORTH OR SOUTH WILL GREATLY
AFFECT EVERY PARAMETER OF THE FORECAST. SO MADE ONLY MINOR
MODIFICATIONS. IF MODELS CONTINUE THE CURRENT TRENDS...THE
NORTHWEST HALF...ESPECIALLY THE CORNER...WILL NEED TO HAVE POPS
RAMPED UP CONSIDERABLY.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 440 AM MDT SAT APR 13 2013
AN UPPER LEVEL TROUGH WILL DEEPEN OVER THE WESTERN CONUS TO START
OUT THE PERIOD. THE TROUGH WILL LINGER THERE THROUGH WEDNESDAY
BEFORE MOVING TOWARD THE AREA. WHILE THE UPPER LEVEL TROUGH REMAINS
SEMI STATIONARY LIFT FROM THE TROUGH WILL MOVE OVER THE AREA AND THE
ENVIRONMENT WILL BECOME SATURATED. THE BEST LIFT WILL MOVE OVER THE
AREA TUESDAY NIGHT AND WEDNESDAY. HAVE THE BEST PRECIP. CHANCES FOR
TUESDAY NIGHT DUE TO THE STRONGER FRONTOGENESIS OVER THE AREA
COMPARED TO WEDNESDAY.
ON WEDNESDAY THE MID LEVEL TROUGH MOVES OVER THE AREA AND WINDS
INCREASE AS AN ARCTIC COLD FRONT MOVES THROUGH. THE GUSTY WINDS MAY
CAUSE PATCHY BLOWING SNOW. DURING THE EVENING THE LIFT BEGINS TO
DECLINE AS THE MID LEVEL TROUGH MOVES TO THE EAST AND THE UPPER
LEVEL TROUGH AXIS BEGINS TO MOVE THROUGH THE AREA. PRECIP. COMES TO
AN END THURSDAY MORNING AS THE LAST OF THE LINGERING LIFT FROM THE
MID LEVEL TROUGH MOVES OUT OF THE AREA.
THERE IS STILL SOME UNCERTAINTY AS TO WHAT THE PHASE OF THE PRECIP.
WILL BE FOR PORTIONS OF THE FORECAST SINCE MODELS DISAGREE WITH THE
AMOUNT OF SATURATION ABOVE THE -10C LEVEL...SO HAVE CHOSEN TO GO WITH
A RAIN/SNOW MIX AT THIS TIME WHICH WILL NEGATIVELY AFFECT FORECASTED
SNOWFALL AMOUNTS. IF TEMPERATURES COOL FURTHER SNOW-TO-LIQUID
RATIOS WILL INCREASE WHICH WILL ALSO CAUSE THE SNOWFALL AMOUNTS TO
INCREASE. CURRENTLY HAVE 1-4 INCHES FORECAST ACROSS THE AREA...WITH
THE HIGHER AMOUNTS OVER THE WESTERN PART OF THE AREA WHERE THE
BETTER LIFT WILL BE.
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL...BUT LOW
TEMPERATURES WILL NEAR NORMAL VALUES BY THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1255 PM MDT SAT APR 13 2013
...UPDATED...
SMALL PLUME OF BLOWING DIRT FROM CONSTRUCTION NEAR GLD RUNWAY IS
RESULTING IN A LOCALIZED AREA OF REDUCED VISIBILITIES IN BLOWING
DIRT. THIS SHOULD NOT BECOME WIDESPREAD NOR LONG LASTING.
OTHERWISE...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS AS
A STRONG COLD FRONT MOVES ACROSS THE REGION. WINDS WILL SHIFT FROM
THE SOUTHWEST TO THE NORTHWEST AND INCREASE TO 25 TO 35 MPH
OVERNIGHT AND INTO THE MORNING HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1142 AM MDT SAT APR 13 2013
.UPDATE...
ISSUED AT 838 AM MDT SAT APR 13 2013
DENSE FOG CONTINUES ALONG AND JUST TO THE NORTH OF THE REPUBLICAN
RIVER VALLEY WITH MCK REPORTING LESS THAN A QUARTER MILE
VISIBILITIES. LOOKS LIKE THIS IS CONFINED TO NORTHERN RED WILLOW
AND NORTHEAST HITCHCOCK COUNTY...AND HAVE EXPANDED THE ADVISORY
FOR ANOTHER HOURS. GIVEN THE SMALL SCALE NATURE OF IT...SHOULD
BEGIN TO CLEAR OUT QUICKLY.
UPDATE ISSUED AT 608 AM MDT SAT APR 13 2013
UPDATED FOR A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 440 AM MDT SAT APR 13 2013
FORECAST CONCERNS WILL BE CHANCES OF PRECIPITATION INTO THE
BEGINNING OF NEXT WEEK...FIRE WEATHER CONCERNS TODAY...AND WINDS
TODAY/TONIGHT. SATELLITE SHOWING AN AMPLIFIED AND BLOCKY PATTERN
FROM THE PACIFIC ACROSS NORTH AMERICA INTO THE ATLANTIC. CONTINUES TO
SHOW AN AMPLIFIED AND BLOCKY PATTERN FROM THE PACIFIC INTO EASTERN
NORTH AMERICA. VERY STRONG AND COLD SYSTEM IS DIGGING INTO SOUTHWEST
CANADA AND THE PACIFIC NORTHWEST. CURRENTLY WEST NORTHWEST TO
NORTHWEST RESIDES OVER THE REGION.
AT JET LEVEL...THE MODELS TENDED TO NOT HAVE THE JET AXIS THAT IS
PUNCHING INTO THE PACIFIC NORTHWEST TOO FAR NORTH AND EAST. THE NAM
AND GFS WERE DOING BEST ON THIS SEGMENT. THE MODELS TENDED TO HAVE
THE HEIGHT FIELD TOO FAR SOUTH AND EAST. OVERALL THE GFS...UKMET
AND CANADIAN WERE DOING THE BEST. THE RUC AND ECMWF WERE DOING
SLIGHTLY BETTER THAN THE NAM ON THE SURFACE WIND AND PRESSURE
FIELD. GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE NAM ON
THE LOW LEVEL THERMAL FIELD.
PER THE INITIAL ANALYSIS AND THE PATTERN WE ARE IN...CHOSE THE
MID/UPPER LEVEL SOLUTIONS THAT WERE FURTHER SOUTH AND FASTER
INITIALLY FOLLOWED BY BEING FURTHER SOUTH AND WEST WITH THE INCOMING
LATER.
TODAY/TONIGHT...FIRST WHAT TO DO WITH THE FOG. MODELS...EVEN
MESOSCALE...HAVING DIFFICULTY GRABBING ONTO THE FOG. WHAT IS
COMPLICATING THINGS IS A CLOUD DECK ABOVE THIS THAT HAS BEEN CAUSING
VARIABILITY IN THE FOG FIELD. BASED ON LATEST TRENDS...CHOSE TO GO
AREAS OF FOG IN THE NORTHERN AND WESTERN SECTIONS AND PATCHY
ELSEWHERE. AS THE SUN COMES UP AND THE WINDS BEGIN TO INCREASE...
THE FOG SHOULD BURN OFF.
CROSS MOUNTAIN FLOW WILL CAUSE LEE TROUGH TO DEVELOP RAPIDLY. 3 HOUR
PRESSURE FALLS AND GRADIENT WOULD INDICATE AT LEAST BREEZY POSSIBLY
A LITTLE HIGHER CONDITIONS. THIS WILL HAVE AN AFFECT ON THE FIRE
WEATHER CONDITIONS. REFER TO THAT BELOW. GUIDANCE HAS BEEN COOL THE
LAST FEW DAYS AND NOT BY A LITTLE BIT...EVEN WITH CLOUDS AROUND. SO
TOOK THE WARMEST BIAS AND ADJUSTED IT WITH SOME BIAS/CHANGE IN
FORECAST 850 MB TEMPERATURE TO ARRIVE AT THE HIGHS.
MAIN JET AXIS STAYS NORTH AND WEST OF THE AREA. ALSO MAIN MID LEVEL
AND PV ANOMALY ARE STILL NORTH OF THE AREA. ALSO SOUNDINGS HAVE TOO
MUCH OF A DRY LAYER. THERE IS SOME SURFACE BASED INSTABILITY IN THE
AFTERNOON BUT THAT IS CAPPED. THERE IS NO ELEVATED INSTABILITY PLUS
IT IS CAPPED AS WELL EVEN IF THERE WAS ANY. SO WILL KEEP THIS
PERIOD DRY. HOWEVER...SOME KIND OF PRECIPITATION COULD GET CLOSE TO
THE FAR NORTHERN SECTION. CLOUD COVER AND WESTERLY WINDS/WARM AIR
ADVECTION IN ADVANCE OF THE COLD FRONT THAT ARRIVES LATER TONIGHT
WILL KEEP THE MINS RATHER MILD. THEY MAY NOT BE WARM ENOUGH. RATHER
SUNDAY/SUNDAY NIGHT...RATHER STRONG 3 HOUR PRESSURE RISE WILL CAUSE
BREEZY TO WINDY CONDITIONS BEHIND THE FRONT IN THE MORNING. LEFT
FRONT QUADRANT OF STRONG JET BEGINS TO AFFECT THE AREA AT THE
BEGINNING OF THE DAY AND THEN STARTS GRADUALLY LIFTING TO THE NORTH
AT THE END OF THE DAY. MID LEVEL COLD AIR ADVECTION/BAROCLINIC ZONE
ALONG WITH RATHER STRONG PV ANOMALY PUSHES ACROSS THE AREA AT THE
SAME WITH THE BEST LIFT AND MOISTURE OVER THE NORTHERN PORTION OF THE
AREA. SO EXPANDED POPS THROUGH THE DAY WITH THE HIGHEST IN THE
NORTHERN PORTION. COMBINATION OF CLOUD COVER/PRECIPITATION AND COLD
AIR ADVECTION WILL TEMPERATURES FROM RISING TOO MUCH AND WENT A
LITTLE BELOW GUIDANCE.
RIGHT REAR QUADRANT IS OVER THE AREA DURING THE NIGHT AND GETS
BETTER AS THE NIGHT WHERES ON AND AS THE MID LEVEL BAROCLINIC ZONE
REMAINS OVER THE AREA. PLUS ANOTHER SHORTWAVE TROUGH APPROACHES BY
LATER IN THE NIGHT. CURRENT FORECAST CAPTURES THIS SCENARIO NICELY
AND DID NOT CHANGE IT WITH GREATEST CHANCE OF PRECIPITATION
WILL BE IN THE NORTH WITH A CHANGEOVER OR MIXTURE OF PHASE EXPECTED
IN THE WEST.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF JET/JET AXIS REMAINS
OVER OR NEAR THE NORTHWEST HALF OF THE AREA THROUGH THE PERIOD.
LOW LEVEL UPSLOPE INCREASES THROUGH THE DAY AS STRONG MID LEVEL
SOUTHWEST FLOW ALOFT CAUSES LEE TROUGH TO STRENGTHEN. ALSO A COUPLE
OF SHORTWAVE TROUGHS MOVE THROUGH IN THIS FLOW. ALMOST EVERY
PARAMETER OF THE FORECAST FOR THIS PERIOD WILL BE PROBLEMATIC.
BECAUSE OF THE PROXIMITY OF THE JET AND MID LEVEL LIFT...KEPT THE
HIGHEST POPS IN THAT SECTION. HOWEVER...THERE IS A SHARP CUTOFF
BETWEEN A LOT OF CLOUDS/NO CLOUDS AND PRECIPITATION/NO
PRECIPITATION. SO ANY SUBTLE SHIFT NORTH OR SOUTH WILL GREATLY
AFFECT EVERY PARAMETER OF THE FORECAST. SO MADE ONLY MINOR
MODIFICATIONS. IF MODELS CONTINUE THE CURRENT TRENDS...THE
NORTHWEST HALF...ESPECIALLY THE CORNER...WILL NEED TO HAVE POPS
RAMPED UP CONSIDERABLY.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 440 AM MDT SAT APR 13 2013
AN UPPER LEVEL TROUGH WILL DEEPEN OVER THE WESTERN CONUS TO START
OUT THE PERIOD. THE TROUGH WILL LINGER THERE THROUGH WEDNESDAY
BEFORE MOVING TOWARD THE AREA. WHILE THE UPPER LEVEL TROUGH REMAINS
SEMI STATIONARY LIFT FROM THE TROUGH WILL MOVE OVER THE AREA AND THE
ENVIRONMENT WILL BECOME SATURATED. THE BEST LIFT WILL MOVE OVER THE
AREA TUESDAY NIGHT AND WEDNESDAY. HAVE THE BEST PRECIP. CHANCES FOR
TUESDAY NIGHT DUE TO THE STRONGER FRONTOGENESIS OVER THE AREA
COMPARED TO WEDNESDAY.
ON WEDNESDAY THE MID LEVEL TROUGH MOVES OVER THE AREA AND WINDS
INCREASE AS AN ARCTIC COLD FRONT MOVES THROUGH. THE GUSTY WINDS MAY
CAUSE PATCHY BLOWING SNOW. DURING THE EVENING THE LIFT BEGINS TO
DECLINE AS THE MID LEVEL TROUGH MOVES TO THE EAST AND THE UPPER
LEVEL TROUGH AXIS BEGINS TO MOVE THROUGH THE AREA. PRECIP. COMES TO
AN END THURSDAY MORNING AS THE LAST OF THE LINGERING LIFT FROM THE
MID LEVEL TROUGH MOVES OUT OF THE AREA.
THERE IS STILL SOME UNCERTAINTY AS TO WHAT THE PHASE OF THE PRECIP.
WILL BE FOR PORTIONS OF THE FORECAST SINCE MODELS DISAGREE WITH THE
AMOUNT OF SATURATION ABOVE THE -10C LEVEL...SO HAVE CHOSEN TO GO WITH
A RAIN/SNOW MIX AT THIS TIME WHICH WILL NEGATIVELY AFFECT FORECASTED
SNOWFALL AMOUNTS. IF TEMPERATURES COOL FURTHER SNOW-TO-LIQUID
RATIOS WILL INCREASE WHICH WILL ALSO CAUSE THE SNOWFALL AMOUNTS TO
INCREASE. CURRENTLY HAVE 1-4 INCHES FORECAST ACROSS THE AREA...WITH
THE HIGHER AMOUNTS OVER THE WESTERN PART OF THE AREA WHERE THE
BETTER LIFT WILL BE.
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL...BUT LOW
TEMPERATURES WILL NEAR NORMAL VALUES BY THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1138 AM MDT SAT APR 13 2013
VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24 HOURS AS A STRONG COLD
FRONT MOVES ACROSS THE REGION. WINDS WILL SHIFT FROM THE SOUTHWEST
TO THE NORTHWEST AND INCREASE TO 25 TO 35 MPH OVERNIGHT AND INTO
THE MORNING HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
845 AM MDT SAT APR 13 2013
.UPDATE...
ISSUED AT 838 AM MDT SAT APR 13 2013
DENSE FOG CONTINUES ALONG AND JUST TO THE NORTH OF THE REPUBLICAN
RIVER VALLEY WITH MCK REPORTING LESS THAN A QUARTER MILE
VISIBILITIES. LOOKS LIKE THIS IS CONFINED TO NORTHERN RED WILLOW
AND NORTHEAST HITCHCOCK COUNTY...AND HAVE EXPANDED THE ADVISORY
FOR ANOTHER HOURS. GIVEN THE SMALL SCALE NATURE OF IT...SHOULD
BEGIN TO CLEAR OUT QUICKLY.
UPDATE ISSUED AT 608 AM MDT SAT APR 13 2013
UPDATED FOR A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 440 AM MDT SAT APR 13 2013
FORECAST CONCERNS WILL BE CHANCES OF PRECIPITATION INTO THE
BEGINNING OF NEXT WEEK...FIRE WEATHER CONCERNS TODAY...AND WINDS
TODAY/TONIGHT. SATELLITE SHOWING AN AMPLIFIED AND BLOCKY PATTERN
FROM THE PACIFIC ACROSS NORTH AMERICA INTO THE ATLANTIC. CONTINUES TO
SHOW AN AMPLIFIED AND BLOCKY PATTERN FROM THE PACIFIC INTO EASTERN
NORTH AMERICA. VERY STRONG AND COLD SYSTEM IS DIGGING INTO SOUTHWEST
CANADA AND THE PACIFIC NORTHWEST. CURRENTLY WEST NORTHWEST TO
NORTHWEST RESIDES OVER THE REGION.
AT JET LEVEL...THE MODELS TENDED TO NOT HAVE THE JET AXIS THAT IS
PUNCHING INTO THE PACIFIC NORTHWEST TOO FAR NORTH AND EAST. THE NAM
AND GFS WERE DOING BEST ON THIS SEGMENT. THE MODELS TENDED TO HAVE
THE HEIGHT FIELD TOO FAR SOUTH AND EAST. OVERALL THE GFS...UKMET
AND CANADIAN WERE DOING THE BEST. THE RUC AND ECMWF WERE DOING
SLIGHTLY BETTER THAN THE NAM ON THE SURFACE WIND AND PRESSURE
FIELD. GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE NAM ON
THE LOW LEVEL THERMAL FIELD.
PER THE INITIAL ANALYSIS AND THE PATTERN WE ARE IN...CHOSE THE
MID/UPPER LEVEL SOLUTIONS THAT WERE FURTHER SOUTH AND FASTER
INITIALLY FOLLOWED BY BEING FURTHER SOUTH AND WEST WITH THE INCOMING
LATER.
TODAY/TONIGHT...FIRST WHAT TO DO WITH THE FOG. MODELS...EVEN
MESOSCALE...HAVING DIFFICULTY GRABBING ONTO THE FOG. WHAT IS
COMPLICATING THINGS IS A CLOUD DECK ABOVE THIS THAT HAS BEEN CAUSING
VARIABILITY IN THE FOG FIELD. BASED ON LATEST TRENDS...CHOSE TO GO
AREAS OF FOG IN THE NORTHERN AND WESTERN SECTIONS AND PATCHY
ELSEWHERE. AS THE SUN COMES UP AND THE WINDS BEGIN TO INCREASE...
THE FOG SHOULD BURN OFF.
CROSS MOUNTAIN FLOW WILL CAUSE LEE TROUGH TO DEVELOP RAPIDLY. 3 HOUR
PRESSURE FALLS AND GRADIENT WOULD INDICATE AT LEAST BREEZY POSSIBLY
A LITTLE HIGHER CONDITIONS. THIS WILL HAVE AN AFFECT ON THE FIRE
WEATHER CONDITIONS. REFER TO THAT BELOW. GUIDANCE HAS BEEN COOL THE
LAST FEW DAYS AND NOT BY A LITTLE BIT...EVEN WITH CLOUDS AROUND. SO
TOOK THE WARMEST BIAS AND ADJUSTED IT WITH SOME BIAS/CHANGE IN
FORECAST 850 MB TEMPERATURE TO ARRIVE AT THE HIGHS.
MAIN JET AXIS STAYS NORTH AND WEST OF THE AREA. ALSO MAIN MID LEVEL
AND PV ANOMALY ARE STILL NORTH OF THE AREA. ALSO SOUNDINGS HAVE TOO
MUCH OF A DRY LAYER. THERE IS SOME SURFACE BASED INSTABILITY IN THE
AFTERNOON BUT THAT IS CAPPED. THERE IS NO ELEVATED INSTABILITY PLUS
IT IS CAPPED AS WELL EVEN IF THERE WAS ANY. SO WILL KEEP THIS
PERIOD DRY. HOWEVER...SOME KIND OF PRECIPITATION COULD GET CLOSE TO
THE FAR NORTHERN SECTION. CLOUD COVER AND WESTERLY WINDS/WARM AIR
ADVECTION IN ADVANCE OF THE COLD FRONT THAT ARRIVES LATER TONIGHT
WILL KEEP THE MINS RATHER MILD. THEY MAY NOT BE WARM ENOUGH. RATHER
SUNDAY/SUNDAY NIGHT...RATHER STRONG 3 HOUR PRESSURE RISE WILL CAUSE
BREEZY TO WINDY CONDITIONS BEHIND THE FRONT IN THE MORNING. LEFT
FRONT QUADRANT OF STRONG JET BEGINS TO AFFECT THE AREA AT THE
BEGINNING OF THE DAY AND THEN STARTS GRADUALLY LIFTING TO THE NORTH
AT THE END OF THE DAY. MID LEVEL COLD AIR ADVECTION/BAROCLINIC ZONE
ALONG WITH RATHER STRONG PV ANOMALY PUSHES ACROSS THE AREA AT THE
SAME WITH THE BEST LIFT AND MOISTURE OVER THE NORTHERN PORTION OF THE
AREA. SO EXPANDED POPS THROUGH THE DAY WITH THE HIGHEST IN THE
NORTHERN PORTION. COMBINATION OF CLOUD COVER/PRECIPITATION AND COLD
AIR ADVECTION WILL TEMPERATURES FROM RISING TOO MUCH AND WENT A
LITTLE BELOW GUIDANCE.
RIGHT REAR QUADRANT IS OVER THE AREA DURING THE NIGHT AND GETS
BETTER AS THE NIGHT WHERES ON AND AS THE MID LEVEL BAROCLINIC ZONE
REMAINS OVER THE AREA. PLUS ANOTHER SHORTWAVE TROUGH APPROACHES BY
LATER IN THE NIGHT. CURRENT FORECAST CAPTURES THIS SCENARIO NICELY
AND DID NOT CHANGE IT WITH GREATEST CHANCE OF PRECIPITATION
WILL BE IN THE NORTH WITH A CHANGEOVER OR MIXTURE OF PHASE EXPECTED
IN THE WEST.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF JET/JET AXIS REMAINS
OVER OR NEAR THE NORTHWEST HALF OF THE AREA THROUGH THE PERIOD.
LOW LEVEL UPSLOPE INCREASES THROUGH THE DAY AS STRONG MID LEVEL
SOUTHWEST FLOW ALOFT CAUSES LEE TROUGH TO STRENGTHEN. ALSO A COUPLE
OF SHORTWAVE TROUGHS MOVE THROUGH IN THIS FLOW. ALMOST EVERY
PARAMETER OF THE FORECAST FOR THIS PERIOD WILL BE PROBLEMATIC.
BECAUSE OF THE PROXIMITY OF THE JET AND MID LEVEL LIFT...KEPT THE
HIGHEST POPS IN THAT SECTION. HOWEVER...THERE IS A SHARP CUTOFF
BETWEEN A LOT OF CLOUDS/NO CLOUDS AND PRECIPITATION/NO
PRECIPITATION. SO ANY SUBTLE SHIFT NORTH OR SOUTH WILL GREATLY
AFFECT EVERY PARAMETER OF THE FORECAST. SO MADE ONLY MINOR
MODIFICATIONS. IF MODELS CONTINUE THE CURRENT TRENDS...THE
NORTHWEST HALF...ESPECIALLY THE CORNER...WILL NEED TO HAVE POPS
RAMPED UP CONSIDERABLY.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 440 AM MDT SAT APR 13 2013
AN UPPER LEVEL TROUGH WILL DEEPEN OVER THE WESTERN CONUS TO START
OUT THE PERIOD. THE TROUGH WILL LINGER THERE THROUGH WEDNESDAY
BEFORE MOVING TOWARD THE AREA. WHILE THE UPPER LEVEL TROUGH REMAINS
SEMI STATIONARY LIFT FROM THE TROUGH WILL MOVE OVER THE AREA AND THE
ENVIRONMENT WILL BECOME SATURATED. THE BEST LIFT WILL MOVE OVER THE
AREA TUESDAY NIGHT AND WEDNESDAY. HAVE THE BEST PRECIP. CHANCES FOR
TUESDAY NIGHT DUE TO THE STRONGER FRONTOGENESIS OVER THE AREA
COMPARED TO WEDNESDAY.
ON WEDNESDAY THE MID LEVEL TROUGH MOVES OVER THE AREA AND WINDS
INCREASE AS AN ARCTIC COLD FRONT MOVES THROUGH. THE GUSTY WINDS MAY
CAUSE PATCHY BLOWING SNOW. DURING THE EVENING THE LIFT BEGINS TO
DECLINE AS THE MID LEVEL TROUGH MOVES TO THE EAST AND THE UPPER
LEVEL TROUGH AXIS BEGINS TO MOVE THROUGH THE AREA. PRECIP. COMES TO
AN END THURSDAY MORNING AS THE LAST OF THE LINGERING LIFT FROM THE
MID LEVEL TROUGH MOVES OUT OF THE AREA.
THERE IS STILL SOME UNCERTAINTY AS TO WHAT THE PHASE OF THE PRECIP.
WILL BE FOR PORTIONS OF THE FORECAST SINCE MODELS DISAGREE WITH THE
AMOUNT OF SATURATION ABOVE THE -10C LEVEL...SO HAVE CHOSEN TO GO WITH
A RAIN/SNOW MIX AT THIS TIME WHICH WILL NEGATIVELY AFFECT FORECASTED
SNOWFALL AMOUNTS. IF TEMPERATURES COOL FURTHER SNOW-TO-LIQUID
RATIOS WILL INCREASE WHICH WILL ALSO CAUSE THE SNOWFALL AMOUNTS TO
INCREASE. CURRENTLY HAVE 1-4 INCHES FORECAST ACROSS THE AREA...WITH
THE HIGHER AMOUNTS OVER THE WESTERN PART OF THE AREA WHERE THE
BETTER LIFT WILL BE.
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL...BUT LOW
TEMPERATURES WILL NEAR NORMAL VALUES BY THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 552 AM MDT SAT APR 13 2013
INITIAL CONCERN WILL BE FOG AND STRATUS. AT THIS TIME LIFR
CONDITIONS ARE OCCURRING AT KMCK AND ARE EXPECTED TO CONTINUE
UNTIL 15Z. AT KGLD...STRATUS AND FOG ARE NOT CURRENTLY AFFECTING
THE SITE BUT ARE NOT THAT FAR AWAY AND WILL HAVE THE POTENTIAL TO
AFFECT THE SITES WITH MVFR CONDITIONS. AFTER THE FOG AND STRATUS
ARE GONE GUSTY SOUTHERLY WINDS ARE EXPECTED UNTIL EARLY EVENING.
THUNDERSTORMS LATER THIS EVENING AND OVERNIGHT APPEAR TO STAY
NORTH AT KMCK SO NO MENTION WAS MADE IN THE TAF. AFTER 06Z A
STRONG COLD FRONT WILL MOVE THROUGH AND CREATE GUSTY NORTHWEST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 440 AM MDT SAT APR 13 2013
CRITICAL FIRE WEATHER CONDITIONS WILL BE CLOSE IN CHEYENNE AND
KIT CARSON COUNTIES...ESPECIALLY THE WESTERN SECTIONS. CONDITIONS
WILL BE VERY CLOSE. IF THIS MORNINGS CLOUD COVER IS SLOW TO BURN
OFF THEN MIXING WILL BE SLOWER TO COMMENCE AS WELL. AT THIS TIME...
IT WILL BE CLOSE IF THE 3 HOUR REQUIREMENT WILL BE REALIZED. AT THIS
TIME CHOSE TO NOT ISSUE A HIGHLIGHT. BUT WILL CONTINUE TO MONITOR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 11 AM CDT THIS MORNING FOR NEZ080-081.
&&
$$
UPDATE...JRM
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...BULLER
FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
609 AM MDT SAT APR 13 2013
.UPDATE...
ISSUED AT 608 AM MDT SAT APR 13 2013
UPDATED FOR A DENSE FOG ADVISORY FOR HITCHCOCK AND RED WILLOW.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 440 AM MDT SAT APR 13 2013
FORECAST CONCERNS WILL BE CHANCES OF PRECIPITATION INTO THE
BEGINNING OF NEXT WEEK...FIRE WEATHER CONCERNS TODAY...AND WINDS
TODAY/TONIGHT. SATELLITE SHOWING AN AMPLIFIED AND BLOCKY PATTERN
FROM THE PACIFIC ACROSS NORTH AMERICA INTO THE ATLANTIC. CONTINUES TO
SHOW AN AMPLIFIED AND BLOCKY PATTERN FROM THE PACIFIC INTO EASTERN
NORTH AMERICA. VERY STRONG AND COLD SYSTEM IS DIGGING INTO SOUTHWEST
CANADA AND THE PACIFIC NORTHWEST. CURRENTLY WEST NORTHWEST TO
NORTHWEST RESIDES OVER THE REGION.
AT JET LEVEL...THE MODELS TENDED TO NOT HAVE THE JET AXIS THAT IS
PUNCHING INTO THE PACIFIC NORTHWEST TOO FAR NORTH AND EAST. THE NAM
AND GFS WERE DOING BEST ON THIS SEGMENT. THE MODELS TENDED TO HAVE
THE HEIGHT FIELD TOO FAR SOUTH AND EAST. OVERALL THE GFS...UKMET
AND CANADIAN WERE DOING THE BEST. THE RUC AND ECMWF WERE DOING
SLIGHTLY BETTER THAN THE NAM ON THE SURFACE WIND AND PRESSURE
FIELD. GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE NAM ON
THE LOW LEVEL THERMAL FIELD.
PER THE INITIAL ANALYSIS AND THE PATTERN WE ARE IN...CHOSE THE
MID/UPPER LEVEL SOLUTIONS THAT WERE FURTHER SOUTH AND FASTER
INITIALLY FOLLOWED BY BEING FURTHER SOUTH AND WEST WITH THE INCOMING
LATER.
TODAY/TONIGHT...FIRST WHAT TO DO WITH THE FOG. MODELS...EVEN
MESOSCALE...HAVING DIFFICULTY GRABBING ONTO THE FOG. WHAT IS
COMPLICATING THINGS IS A CLOUD DECK ABOVE THIS THAT HAS BEEN CAUSING
VARIABILITY IN THE FOG FIELD. BASED ON LATEST TRENDS...CHOSE TO GO
AREAS OF FOG IN THE NORTHERN AND WESTERN SECTIONS AND PATCHY
ELSEWHERE. AS THE SUN COMES UP AND THE WINDS BEGIN TO INCREASE...
THE FOG SHOULD BURN OFF.
CROSS MOUNTAIN FLOW WILL CAUSE LEE TROUGH TO DEVELOP RAPIDLY. 3 HOUR
PRESSURE FALLS AND GRADIENT WOULD INDICATE AT LEAST BREEZY POSSIBLY
A LITTLE HIGHER CONDITIONS. THIS WILL HAVE AN AFFECT ON THE FIRE
WEATHER CONDITIONS. REFER TO THAT BELOW. GUIDANCE HAS BEEN COOL THE
LAST FEW DAYS AND NOT BY A LITTLE BIT...EVEN WITH CLOUDS AROUND. SO
TOOK THE WARMEST BIAS AND ADJUSTED IT WITH SOME BIAS/CHANGE IN
FORECAST 850 MB TEMPERATURE TO ARRIVE AT THE HIGHS.
MAIN JET AXIS STAYS NORTH AND WEST OF THE AREA. ALSO MAIN MID LEVEL
AND PV ANOMALY ARE STILL NORTH OF THE AREA. ALSO SOUNDINGS HAVE TOO
MUCH OF A DRY LAYER. THERE IS SOME SURFACE BASED INSTABILITY IN THE
AFTERNOON BUT THAT IS CAPPED. THERE IS NO ELEVATED INSTABILITY PLUS
IT IS CAPPED AS WELL EVEN IF THERE WAS ANY. SO WILL KEEP THIS
PERIOD DRY. HOWEVER...SOME KIND OF PRECIPITATION COULD GET CLOSE TO
THE FAR NORTHERN SECTION. CLOUD COVER AND WESTERLY WINDS/WARM AIR
ADVECTION IN ADVANCE OF THE COLD FRONT THAT ARRIVES LATER TONIGHT
WILL KEEP THE MINS RATHER MILD. THEY MAY NOT BE WARM ENOUGH. RATHER
SUNDAY/SUNDAY NIGHT...RATHER STRONG 3 HOUR PRESSURE RISE WILL CAUSE
BREEZY TO WINDY CONDITIONS BEHIND THE FRONT IN THE MORNING. LEFT
FRONT QUADRANT OF STRONG JET BEGINS TO AFFECT THE AREA AT THE
BEGINNING OF THE DAY AND THEN STARTS GRADUALLY LIFTING TO THE NORTH
AT THE END OF THE DAY. MID LEVEL COLD AIR ADVECTION/BAROCLINIC ZONE
ALONG WITH RATHER STRONG PV ANOMALY PUSHES ACROSS THE AREA AT THE
SAME WITH THE BEST LIFT AND MOISTURE OVER THE NORTHERN PORTION OF THE
AREA. SO EXPANDED POPS THROUGH THE DAY WITH THE HIGHEST IN THE
NORTHERN PORTION. COMBINATION OF CLOUD COVER/PRECIPITATION AND COLD
AIR ADVECTION WILL TEMPERATURES FROM RISING TOO MUCH AND WENT A
LITTLE BELOW GUIDANCE.
RIGHT REAR QUADRANT IS OVER THE AREA DURING THE NIGHT AND GETS
BETTER AS THE NIGHT WHERES ON AND AS THE MID LEVEL BAROCLINIC ZONE
REMAINS OVER THE AREA. PLUS ANOTHER SHORTWAVE TROUGH APPROACHES BY
LATER IN THE NIGHT. CURRENT FORECAST CAPTURES THIS SCENARIO NICELY
AND DID NOT CHANGE IT WITH GREATEST CHANCE OF PRECIPITATION
WILL BE IN THE NORTH WITH A CHANGEOVER OR MIXTURE OF PHASE EXPECTED
IN THE WEST.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF JET/JET AXIS REMAINS
OVER OR NEAR THE NORTHWEST HALF OF THE AREA THROUGH THE PERIOD.
LOW LEVEL UPSLOPE INCREASES THROUGH THE DAY AS STRONG MID LEVEL
SOUTHWEST FLOW ALOFT CAUSES LEE TROUGH TO STRENGTHEN. ALSO A COUPLE
OF SHORTWAVE TROUGHS MOVE THROUGH IN THIS FLOW. ALMOST EVERY
PARAMETER OF THE FORECAST FOR THIS PERIOD WILL BE PROBLEMATIC.
BECAUSE OF THE PROXIMITY OF THE JET AND MID LEVEL LIFT...KEPT THE
HIGHEST POPS IN THAT SECTION. HOWEVER...THERE IS A SHARP CUTOFF
BETWEEN A LOT OF CLOUDS/NO CLOUDS AND PRECIPITATION/NO
PRECIPITATION. SO ANY SUBTLE SHIFT NORTH OR SOUTH WILL GREATLY
AFFECT EVERY PARAMETER OF THE FORECAST. SO MADE ONLY MINOR
MODIFICATIONS. IF MODELS CONTINUE THE CURRENT TRENDS...THE
NORTHWEST HALF...ESPECIALLY THE CORNER...WILL NEED TO HAVE POPS
RAMPED UP CONSIDERABLY.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 440 AM MDT SAT APR 13 2013
AN UPPER LEVEL TROUGH WILL DEEPEN OVER THE WESTERN CONUS TO START
OUT THE PERIOD. THE TROUGH WILL LINGER THERE THROUGH WEDNESDAY
BEFORE MOVING TOWARD THE AREA. WHILE THE UPPER LEVEL TROUGH REMAINS
SEMI STATIONARY LIFT FROM THE TROUGH WILL MOVE OVER THE AREA AND THE
ENVIRONMENT WILL BECOME SATURATED. THE BEST LIFT WILL MOVE OVER THE
AREA TUESDAY NIGHT AND WEDNESDAY. HAVE THE BEST PRECIP. CHANCES FOR
TUESDAY NIGHT DUE TO THE STRONGER FRONTOGENESIS OVER THE AREA
COMPARED TO WEDNESDAY.
ON WEDNESDAY THE MID LEVEL TROUGH MOVES OVER THE AREA AND WINDS
INCREASE AS AN ARCTIC COLD FRONT MOVES THROUGH. THE GUSTY WINDS MAY
CAUSE PATCHY BLOWING SNOW. DURING THE EVENING THE LIFT BEGINS TO
DECLINE AS THE MID LEVEL TROUGH MOVES TO THE EAST AND THE UPPER
LEVEL TROUGH AXIS BEGINS TO MOVE THROUGH THE AREA. PRECIP. COMES TO
AN END THURSDAY MORNING AS THE LAST OF THE LINGERING LIFT FROM THE
MID LEVEL TROUGH MOVES OUT OF THE AREA.
THERE IS STILL SOME UNCERTAINTY AS TO WHAT THE PHASE OF THE PRECIP.
WILL BE FOR PORTIONS OF THE FORECAST SINCE MODELS DISAGREE WITH THE
AMOUNT OF SATURATION ABOVE THE -10C LEVEL...SO HAVE CHOSEN TO GO WITH
A RAIN/SNOW MIX AT THIS TIME WHICH WILL NEGATIVELY AFFECT FORECASTED
SNOWFALL AMOUNTS. IF TEMPERATURES COOL FURTHER SNOW-TO-LIQUID
RATIOS WILL INCREASE WHICH WILL ALSO CAUSE THE SNOWFALL AMOUNTS TO
INCREASE. CURRENTLY HAVE 1-4 INCHES FORECAST ACROSS THE AREA...WITH
THE HIGHER AMOUNTS OVER THE WESTERN PART OF THE AREA WHERE THE
BETTER LIFT WILL BE.
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL...BUT LOW
TEMPERATURES WILL NEAR NORMAL VALUES BY THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 552 AM MDT SAT APR 13 2013
INITIAL CONCERN WILL BE FOG AND STRATUS. AT THIS TIME LIFR
CONDITIONS ARE OCCURRING AT KMCK AND ARE EXPECTED TO CONTINUE
UNTIL 15Z. AT KGLD...STRATUS AND FOG ARE NOT CURRENTLY AFFECTING
THE SITE BUT ARE NOT THAT FAR AWAY AND WILL HAVE THE POTENTIAL TO
AFFECT THE SITES WITH MVFR CONDITIONS. AFTER THE FOG AND STRATUS
ARE GONE GUSTY SOUTHERLY WINDS ARE EXPECTED UNTIL EARLY EVENING.
THUNDERSTORMS LATER THIS EVENING AND OVERNIGHT APPEAR TO STAY
NORTH AT KMCK SO NO MENTION WAS MADE IN THE TAF. AFTER 06Z A
STRONG COLD FRONT WILL MOVE THROUGH AND CREATE GUSTY NORTHWEST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 440 AM MDT SAT APR 13 2013
CRITICAL FIRE WEATHER CONDITIONS WILL BE CLOSE IN CHEYENNE AND
KIT CARSON COUNTIES...ESPECIALLY THE WESTERN SECTIONS. CONDITIONS
WILL BE VERY CLOSE. IF THIS MORNINGS CLOUD COVER IS SLOW TO BURN
OFF THEN MIXING WILL BE SLOWER TO COMMENCE AS WELL. AT THIS TIME...
IT WILL BE CLOSE IF THE 3 HOUR REQUIREMENT WILL BE REALIZED. AT THIS
TIME CHOSE TO NOT ISSUE A HIGHLIGHT. BUT WILL CONTINUE TO MONITOR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ080-081.
&&
$$
UPDATE...BULLER
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...BULLER
FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
557 AM MDT SAT APR 13 2013
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 440 AM MDT SAT APR 13 2013
FORECAST CONCERNS WILL BE CHANCES OF PRECIPITATION INTO THE
BEGINNING OF NEXT WEEK...FIRE WEATHER CONCERNS TODAY...AND WINDS
TODAY/TONIGHT. SATELLITE SHOWING AN AMPLIFIED AND BLOCKY PATTERN
FROM THE PACIFIC ACROSS NORTH AMERICA INTO THE ATLANTIC. CONTINUES TO
SHOW AN AMPLIFIED AND BLOCKY PATTERN FROM THE PACIFIC INTO EASTERN
NORTH AMERICA. VERY STRONG AND COLD SYSTEM IS DIGGING INTO SOUTHWEST
CANADA AND THE PACIFIC NORTHWEST. CURRENTLY WEST NORTHWEST TO
NORTHWEST RESIDES OVER THE REGION.
AT JET LEVEL...THE MODELS TENDED TO NOT HAVE THE JET AXIS THAT IS
PUNCHING INTO THE PACIFIC NORTHWEST TOO FAR NORTH AND EAST. THE NAM
AND GFS WERE DOING BEST ON THIS SEGMENT. THE MODELS TENDED TO HAVE
THE HEIGHT FIELD TOO FAR SOUTH AND EAST. OVERALL THE GFS...UKMET
AND CANADIAN WERE DOING THE BEST. THE RUC AND ECMWF WERE DOING
SLIGHTLY BETTER THAN THE NAM ON THE SURFACE WIND AND PRESSURE
FIELD. GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE NAM ON
THE LOW LEVEL THERMAL FIELD.
PER THE INITIAL ANALYSIS AND THE PATTERN WE ARE IN...CHOSE THE
MID/UPPER LEVEL SOLUTIONS THAT WERE FURTHER SOUTH AND FASTER
INITIALLY FOLLOWED BY BEING FURTHER SOUTH AND WEST WITH THE INCOMING
LATER.
TODAY/TONIGHT...FIRST WHAT TO DO WITH THE FOG. MODELS...EVEN
MESOSCALE...HAVING DIFFICULTY GRABBING ONTO THE FOG. WHAT IS
COMPLICATING THINGS IS A CLOUD DECK ABOVE THIS THAT HAS BEEN CAUSING
VARIABILITY IN THE FOG FIELD. BASED ON LATEST TRENDS...CHOSE TO GO
AREAS OF FOG IN THE NORTHERN AND WESTERN SECTIONS AND PATCHY
ELSEWHERE. AS THE SUN COMES UP AND THE WINDS BEGIN TO INCREASE...
THE FOG SHOULD BURN OFF.
CROSS MOUNTAIN FLOW WILL CAUSE LEE TROUGH TO DEVELOP RAPIDLY. 3 HOUR
PRESSURE FALLS AND GRADIENT WOULD INDICATE AT LEAST BREEZY POSSIBLY
A LITTLE HIGHER CONDITIONS. THIS WILL HAVE AN AFFECT ON THE FIRE
WEATHER CONDITIONS. REFER TO THAT BELOW. GUIDANCE HAS BEEN COOL THE
LAST FEW DAYS AND NOT BY A LITTLE BIT...EVEN WITH CLOUDS AROUND. SO
TOOK THE WARMEST BIAS AND ADJUSTED IT WITH SOME BIAS/CHANGE IN
FORECAST 850 MB TEMPERATURE TO ARRIVE AT THE HIGHS.
MAIN JET AXIS STAYS NORTH AND WEST OF THE AREA. ALSO MAIN MID LEVEL
AND PV ANOMALY ARE STILL NORTH OF THE AREA. ALSO SOUNDINGS HAVE TOO
MUCH OF A DRY LAYER. THERE IS SOME SURFACE BASED INSTABILITY IN THE
AFTERNOON BUT THAT IS CAPPED. THERE IS NO ELEVATED INSTABILITY PLUS
IT IS CAPPED AS WELL EVEN IF THERE WAS ANY. SO WILL KEEP THIS
PERIOD DRY. HOWEVER...SOME KIND OF PRECIPITATION COULD GET CLOSE TO
THE FAR NORTHERN SECTION. CLOUD COVER AND WESTERLY WINDS/WARM AIR
ADVECTION IN ADVANCE OF THE COLD FRONT THAT ARRIVES LATER TONIGHT
WILL KEEP THE MINS RATHER MILD. THEY MAY NOT BE WARM ENOUGH. RATHER
SUNDAY/SUNDAY NIGHT...RATHER STRONG 3 HOUR PRESSURE RISE WILL CAUSE
BREEZY TO WINDY CONDITIONS BEHIND THE FRONT IN THE MORNING. LEFT
FRONT QUADRANT OF STRONG JET BEGINS TO AFFECT THE AREA AT THE
BEGINNING OF THE DAY AND THEN STARTS GRADUALLY LIFTING TO THE NORTH
AT THE END OF THE DAY. MID LEVEL COLD AIR ADVECTION/BAROCLINIC ZONE
ALONG WITH RATHER STRONG PV ANOMALY PUSHES ACROSS THE AREA AT THE
SAME WITH THE BEST LIFT AND MOISTURE OVER THE NORTHERN PORTION OF THE
AREA. SO EXPANDED POPS THROUGH THE DAY WITH THE HIGHEST IN THE
NORTHERN PORTION. COMBINATION OF CLOUD COVER/PRECIPITATION AND COLD
AIR ADVECTION WILL TEMPERATURES FROM RISING TOO MUCH AND WENT A
LITTLE BELOW GUIDANCE.
RIGHT REAR QUADRANT IS OVER THE AREA DURING THE NIGHT AND GETS
BETTER AS THE NIGHT WHERES ON AND AS THE MID LEVEL BAROCLINIC ZONE
REMAINS OVER THE AREA. PLUS ANOTHER SHORTWAVE TROUGH APPROACHES BY
LATER IN THE NIGHT. CURRENT FORECAST CAPTURES THIS SCENARIO NICELY
AND DID NOT CHANGE IT WITH GREATEST CHANCE OF PRECIPITATION
WILL BE IN THE NORTH WITH A CHANGEOVER OR MIXTURE OF PHASE EXPECTED
IN THE WEST.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF JET/JET AXIS REMAINS
OVER OR NEAR THE NORTHWEST HALF OF THE AREA THROUGH THE PERIOD.
LOW LEVEL UPSLOPE INCREASES THROUGH THE DAY AS STRONG MID LEVEL
SOUTHWEST FLOW ALOFT CAUSES LEE TROUGH TO STRENGTHEN. ALSO A COUPLE
OF SHORTWAVE TROUGHS MOVE THROUGH IN THIS FLOW. ALMOST EVERY
PARAMETER OF THE FORECAST FOR THIS PERIOD WILL BE PROBLEMATIC.
BECAUSE OF THE PROXIMITY OF THE JET AND MID LEVEL LIFT...KEPT THE
HIGHEST POPS IN THAT SECTION. HOWEVER...THERE IS A SHARP CUTOFF
BETWEEN A LOT OF CLOUDS/NO CLOUDS AND PRECIPITATION/NO
PRECIPITATION. SO ANY SUBTLE SHIFT NORTH OR SOUTH WILL GREATLY
AFFECT EVERY PARAMETER OF THE FORECAST. SO MADE ONLY MINOR
MODIFICATIONS. IF MODELS CONTINUE THE CURRENT TRENDS...THE
NORTHWEST HALF...ESPECIALLY THE CORNER...WILL NEED TO HAVE POPS
RAMPED UP CONSIDERABLY.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 440 AM MDT SAT APR 13 2013
AN UPPER LEVEL TROUGH WILL DEEPEN OVER THE WESTERN CONUS TO START
OUT THE PERIOD. THE TROUGH WILL LINGER THERE THROUGH WEDNESDAY
BEFORE MOVING TOWARD THE AREA. WHILE THE UPPER LEVEL TROUGH REMAINS
SEMI STATIONARY LIFT FROM THE TROUGH WILL MOVE OVER THE AREA AND THE
ENVIRONMENT WILL BECOME SATURATED. THE BEST LIFT WILL MOVE OVER THE
AREA TUESDAY NIGHT AND WEDNESDAY. HAVE THE BEST PRECIP. CHANCES FOR
TUESDAY NIGHT DUE TO THE STRONGER FRONTOGENESIS OVER THE AREA
COMPARED TO WEDNESDAY.
ON WEDNESDAY THE MID LEVEL TROUGH MOVES OVER THE AREA AND WINDS
INCREASE AS AN ARCTIC COLD FRONT MOVES THROUGH. THE GUSTY WINDS MAY
CAUSE PATCHY BLOWING SNOW. DURING THE EVENING THE LIFT BEGINS TO
DECLINE AS THE MID LEVEL TROUGH MOVES TO THE EAST AND THE UPPER
LEVEL TROUGH AXIS BEGINS TO MOVE THROUGH THE AREA. PRECIP. COMES TO
AN END THURSDAY MORNING AS THE LAST OF THE LINGERING LIFT FROM THE
MID LEVEL TROUGH MOVES OUT OF THE AREA.
THERE IS STILL SOME UNCERTAINTY AS TO WHAT THE PHASE OF THE PRECIP.
WILL BE FOR PORTIONS OF THE FORECAST SINCE MODELS DISAGREE WITH THE
AMOUNT OF SATURATION ABOVE THE -10C LEVEL...SO HAVE CHOSEN TO GO WITH
A RAIN/SNOW MIX AT THIS TIME WHICH WILL NEGATIVELY AFFECT FORECASTED
SNOWFALL AMOUNTS. IF TEMPERATURES COOL FURTHER SNOW-TO-LIQUID
RATIOS WILL INCREASE WHICH WILL ALSO CAUSE THE SNOWFALL AMOUNTS TO
INCREASE. CURRENTLY HAVE 1-4 INCHES FORECAST ACROSS THE AREA...WITH
THE HIGHER AMOUNTS OVER THE WESTERN PART OF THE AREA WHERE THE
BETTER LIFT WILL BE.
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL...BUT LOW
TEMPERATURES WILL NEAR NORMAL VALUES BY THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 552 AM MDT SAT APR 13 2013
INITIAL CONCERN WILL BE FOG AND STRATUS. AT THIS TIME LIFR
CONDITIONS ARE OCCURRING AT KMCK AND ARE EXPECTED TO CONTINUE
UNTIL 15Z. AT KGLD...STRATUS AND FOG ARE NOT CURRENTLY AFFECTING
THE SITE BUT ARE NOT THAT FAR AWAY AND WILL HAVE THE POTENTIAL TO
AFFECT THE SITES WITH MVFR CONDITIONS. AFTER THE FOG AND STRATUS
ARE GONE GUSTY SOUTHERLY WINDS ARE EXPECTED UNTIL EARLY EVENING.
THUNDERSTORMS LATER THIS EVENING AND OVERNIGHT APPEAR TO STAY
NORTH AT KMCK SO NO MENTION WAS MADE IN THE TAF. AFTER 06Z A
STRONG COLD FRONT WILL MOVE THROUGH AND CREATE GUSTY NORTHWEST
WINDS.
&&
.FIRE WEATHER...
ISSUED AT 440 AM MDT SAT APR 13 2013
CRITICAL FIRE WEATHER CONDITIONS WILL BE CLOSE IN CHEYENNE AND
KIT CARSON COUNTIES...ESPECIALLY THE WESTERN SECTIONS. CONDITIONS
WILL BE VERY CLOSE. IF THIS MORNINGS CLOUD COVER IS SLOW TO BURN
OFF THEN MIXING WILL BE SLOWER TO COMMENCE AS WELL. AT THIS TIME...
IT WILL BE CLOSE IF THE 3 HOUR REQUIREMENT WILL BE REALIZED. AT THIS
TIME CHOSE TO NOT ISSUE A HIGHLIGHT. BUT WILL CONTINUE TO MONITOR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...BULLER
FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
440 AM MDT SAT APR 13 2013
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 440 AM MDT SAT APR 13 2013
FORECAST CONCERNS WILL BE CHANCES OF PRECIPITATION INTO THE
BEGINNING OF NEXT WEEK...FIRE WEATHER CONCERNS TODAY...AND WINDS
TODAY/TONIGHT. SATELLITE SHOWING AN AMPLIFIED AND BLOCKY PATTERN
FROM THE PACIFIC ACROSS NORTH AMERICA INTO THE ATLANTIC. CONTINUES TO
SHOW AN AMPLIFIED AND BLOCKY PATTERN FROM THE PACIFIC INTO EASTERN
NORTH AMERICA. VERY STRONG AND COLD SYSTEM IS DIGGING INTO SOUTHWEST
CANADA AND THE PACIFIC NORTHWEST. CURRENTLY WEST NORTHWEST TO
NORTHWEST RESIDES OVER THE REGION.
AT JET LEVEL...THE MODELS TENDED TO NOT HAVE THE JET AXIS THAT IS
PUNCHING INTO THE PACIFIC NORTHWEST TOO FAR NORTH AND EAST. THE NAM
AND GFS WERE DOING BEST ON THIS SEGMENT. THE MODELS TENDED TO HAVE
THE HEIGHT FIELD TOO FAR SOUTH AND EAST. OVERALL THE GFS...UKMET
AND CANADIAN WERE DOING THE BEST. THE RUC AND ECMWF WERE DOING
SLIGHTLY BETTER THAN THE NAM ON THE SURFACE WIND AND PRESSURE
FIELD. GFS AND CANADIAN WERE DOING A LITTLE BETTER THAN THE NAM ON
THE LOW LEVEL THERMAL FIELD.
PER THE INITIAL ANALYSIS AND THE PATTERN WE ARE IN...CHOSE THE
MID/UPPER LEVEL SOLUTIONS THAT WERE FURTHER SOUTH AND FASTER
INITIALLY FOLLOWED BY BEING FURTHER SOUTH AND WEST WITH THE INCOMING
LATER.
TODAY/TONIGHT...FIRST WHAT TO DO WITH THE FOG. MODELS...EVEN
MESOSCALE...HAVING DIFFICULTY GRABBING ONTO THE FOG. WHAT IS
COMPLICATING THINGS IS A CLOUD DECK ABOVE THIS THAT HAS BEEN CAUSING
VARIABILITY IN THE FOG FIELD. BASED ON LATEST TRENDS...CHOSE TO GO
AREAS OF FOG IN THE NORTHERN AND WESTERN SECTIONS AND PATCHY
ELSEWHERE. AS THE SUN COMES UP AND THE WINDS BEGIN TO INCREASE...
THE FOG SHOULD BURN OFF.
CROSS MOUNTAIN FLOW WILL CAUSE LEE TROUGH TO DEVELOP RAPIDLY. 3 HOUR
PRESSURE FALLS AND GRADIENT WOULD INDICATE AT LEAST BREEZY POSSIBLY
A LITTLE HIGHER CONDITIONS. THIS WILL HAVE AN AFFECT ON THE FIRE
WEATHER CONDITIONS. REFER TO THAT BELOW. GUIDANCE HAS BEEN COOL THE
LAST FEW DAYS AND NOT BY A LITTLE BIT...EVEN WITH CLOUDS AROUND. SO
TOOK THE WARMEST BIAS AND ADJUSTED IT WITH SOME BIAS/CHANGE IN
FORECAST 850 MB TEMPERATURE TO ARRIVE AT THE HIGHS.
MAIN JET AXIS STAYS NORTH AND WEST OF THE AREA. ALSO MAIN MID LEVEL
AND PV ANOMALY ARE STILL NORTH OF THE AREA. ALSO SOUNDINGS HAVE TOO
MUCH OF A DRY LAYER. THERE IS SOME SURFACE BASED INSTABILITY IN THE
AFTERNOON BUT THAT IS CAPPED. THERE IS NO ELEVATED INSTABILITY PLUS
IT IS CAPPED AS WELL EVEN IF THERE WAS ANY. SO WILL KEEP THIS
PERIOD DRY. HOWEVER...SOME KIND OF PRECIPITATION COULD GET CLOSE TO
THE FAR NORTHERN SECTION. CLOUD COVER AND WESTERLY WINDS/WARM AIR
ADVECTION IN ADVANCE OF THE COLD FRONT THAT ARRIVES LATER TONIGHT
WILL KEEP THE MINS RATHER MILD. THEY MAY NOT BE WARM ENOUGH. RATHER
SUNDAY/SUNDAY NIGHT...RATHER STRONG 3 HOUR PRESSURE RISE WILL CAUSE
BREEZY TO WINDY CONDITIONS BEHIND THE FRONT IN THE MORNING. LEFT
FRONT QUADRANT OF STRONG JET BEGINS TO AFFECT THE AREA AT THE
BEGINNING OF THE DAY AND THEN STARTS GRADUALLY LIFTING TO THE NORTH
AT THE END OF THE DAY. MID LEVEL COLD AIR ADVECTION/BAROCLINIC ZONE
ALONG WITH RATHER STRONG PV ANOMALY PUSHES ACROSS THE AREA AT THE
SAME WITH THE BEST LIFT AND MOISTURE OVER THE NORTHERN PORTION OF THE
AREA. SO EXPANDED POPS THROUGH THE DAY WITH THE HIGHEST IN THE
NORTHERN PORTION. COMBINATION OF CLOUD COVER/PRECIPITATION AND COLD
AIR ADVECTION WILL TEMPERATURES FROM RISING TOO MUCH AND WENT A
LITTLE BELOW GUIDANCE.
RIGHT REAR QUADRANT IS OVER THE AREA DURING THE NIGHT AND GETS
BETTER AS THE NIGHT WHERES ON AND AS THE MID LEVEL BAROCLINIC ZONE
REMAINS OVER THE AREA. PLUS ANOTHER SHORTWAVE TROUGH APPROACHES BY
LATER IN THE NIGHT. CURRENT FORECAST CAPTURES THIS SCENARIO NICELY
AND DID NOT CHANGE IT WITH GREATEST CHANCE OF PRECIPITATION
WILL BE IN THE NORTH WITH A CHANGEOVER OR MIXTURE OF PHASE EXPECTED
IN THE WEST.
MONDAY/MONDAY NIGHT...RIGHT REAR QUADRANT OF JET/JET AXIS REMAINS
OVER OR NEAR THE NORTHWEST HALF OF THE AREA THROUGH THE PERIOD.
LOW LEVEL UPSLOPE INCREASES THROUGH THE DAY AS STRONG MID LEVEL
SOUTHWEST FLOW ALOFT CAUSES LEE TROUGH TO STRENGTHEN. ALSO A COUPLE
OF SHORTWAVE TROUGHS MOVE THROUGH IN THIS FLOW. ALMOST EVERY
PARAMETER OF THE FORECAST FOR THIS PERIOD WILL BE PROBLEMATIC.
BECAUSE OF THE PROXIMITY OF THE JET AND MID LEVEL LIFT...KEPT THE
HIGHEST POPS IN THAT SECTION. HOWEVER...THERE IS A SHARP CUTOFF
BETWEEN A LOT OF CLOUDS/NO CLOUDS AND PRECIPITATION/NO
PRECIPITATION. SO ANY SUBTLE SHIFT NORTH OR SOUTH WILL GREATLY
AFFECT EVERY PARAMETER OF THE FORECAST. SO MADE ONLY MINOR
MODIFICATIONS. IF MODELS CONTINUE THE CURRENT TRENDS...THE
NORTHWEST HALF...ESPECIALLY THE CORNER...WILL NEED TO HAVE POPS
RAMPED UP CONSIDERABLY.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 440 AM MDT SAT APR 13 2013
AN UPPER LEVEL TROUGH WILL DEEPEN OVER THE WESTERN CONUS TO START
OUT THE PERIOD. THE TROUGH WILL LINGER THERE THROUGH WEDNESDAY
BEFORE MOVING TOWARD THE AREA. WHILE THE UPPER LEVEL TROUGH REMAINS
SEMI STATIONARY LIFT FROM THE TROUGH WILL MOVE OVER THE AREA AND THE
ENVIRONMENT WILL BECOME SATURATED. THE BEST LIFT WILL MOVE OVER THE
AREA TUESDAY NIGHT AND WEDNESDAY. HAVE THE BEST PRECIP. CHANCES FOR
TUESDAY NIGHT DUE TO THE STRONGER FRONTOGENESIS OVER THE AREA
COMPARED TO WEDNESDAY.
ON WEDNESDAY THE MID LEVEL TROUGH MOVES OVER THE AREA AND WINDS
INCREASE AS AN ARCTIC COLD FRONT MOVES THROUGH. THE GUSTY WINDS MAY
CAUSE PATCHY BLOWING SNOW. DURING THE EVENING THE LIFT BEGINS TO
DECLINE AS THE MID LEVEL TROUGH MOVES TO THE EAST AND THE UPPER
LEVEL TROUGH AXIS BEGINS TO MOVE THROUGH THE AREA. PRECIP. COMES TO
AN END THURSDAY MORNING AS THE LAST OF THE LINGERING LIFT FROM THE
MID LEVEL TROUGH MOVES OUT OF THE AREA.
THERE IS STILL SOME UNCERTAINTY AS TO WHAT THE PHASE OF THE PRECIP.
WILL BE FOR PORTIONS OF THE FORECAST SINCE MODELS DISAGREE WITH THE
AMOUNT OF SATURATION ABOVE THE -10C LEVEL...SO HAVE CHOSEN TO GO WITH
A RAIN/SNOW MIX AT THIS TIME WHICH WILL NEGATIVELY AFFECT FORECASTED
SNOWFALL AMOUNTS. IF TEMPERATURES COOL FURTHER SNOW-TO-LIQUID
RATIOS WILL INCREASE WHICH WILL ALSO CAUSE THE SNOWFALL AMOUNTS TO
INCREASE. CURRENTLY HAVE 1-4 INCHES FORECAST ACROSS THE AREA...WITH
THE HIGHER AMOUNTS OVER THE WESTERN PART OF THE AREA WHERE THE
BETTER LIFT WILL BE.
TEMPERATURES FOR THE PERIOD WILL BE BELOW NORMAL...BUT LOW
TEMPERATURES WILL NEAR NORMAL VALUES BY THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1109 PM MDT FRI APR 12 2013
MOSTLY VFR CONDITIONS ARE EXPECTED AT MCK AND GLD. HOWEVER...
FOLLOWING THE RAIN THIS PAST EVENING...LOW LEVEL MOISTURE AND HIGHER
DEWPOINTS ARE BEING OBSERVED ACROSS THE REGION WITH AREAS OF LOW
CLOUDS AND FOG DEVELOPING AS THE WINDS ARE CURRENTLY CALM TO LIGHT
AND VARIABLE. SO UNTIL 14Z...CONDITIONS MAY VARY BETWEEN MVFR TO
LIFR. BY 14Z...WINDS ACROSS THE REGION SHOULD BEGIN TURNING TO THE
SOUTH AND INCREASE WITH DRYER AIR MOVING INTO THE REGION. AS THIS
OCCURS...EXPECT TO SEE A DECREASE IN THE AMOUNT OF FOG AND LOW CLOUDS
WITH SKIES BECOMING MOSTLY CLEAR BY MID DAY. BY 18Z...SOUTH WINDS
SHOULD ALSO BECOME GUSTY AND PERSIST INTO EARLY SATURDAY EVENING AS
HIGH CLOUDS BEGIN TO INCREASE ACROSS THE REGION AHEAD OF THE NEXT
APPROACHING LOW PRESSURE SYSTEM.
&&
.FIRE WEATHER...
ISSUED AT 440 AM MDT SAT APR 13 2013
CRITICAL FIRE WEATHER CONDITIONS WILL BE CLOSE IN CHEYENNE AND
KIT CARSON COUNTIES...ESPECIALLY THE WESTERN SECTIONS. CONDITIONS
WILL BE VERY CLOSE. IF THIS MORNINGS CLOUD COVER IS SLOW TO BURN
OFF THEN MIXING WILL BE SLOWER TO COMMENCE AS WELL. AT THIS TIME...
IT WILL BE CLOSE IF THE 3 HOUR REQUIREMENT WILL BE REALIZED. AT THIS
TIME CHOSE TO NOT ISSUE A HIGHLIGHT. BUT WILL CONTINUE TO MONITOR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...JTL
AVIATION...LOCKHART
FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
410 AM EDT SAT APR 13 2013
.SYNOPSIS...
LOW PRESSURE AND ASSOCIATED COLD FRONT IS MOVING AWAY FROM THE AREA.
HIGH PRESSURE WILL BUILD OVER THE AREA TODAY AND CONTINUE THROUGH
THIS WEEKEND. THE HIGH WILL MOVE OFF THE COAST EARLY NEXT WEEK AND A
WARM FRONT WILL STALL OVER THE REGION DURING THIS TIME. A STRONGER
FRONT WILL APPROACH FROM THE WEST LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THROUGH 11Z SAT...LOW PRESSURE CENTER THAT WAS NEARLY STATIONARY LAST
EVENING OVER S-CNTRL VIRGINIA FINALLY MOVED NE AND OFF THE EASTERN
SEABOARD AND CONTINUES MOVING AWAY FROM THE AREA. THIS HAS ALLOWED A
COLD FRONT TO PUSH ACROSS THE AREA...OVERTAKING THE BACKDOOR COLD
FRONT THAT HAD SET UP A MARITIME AIRMASS OVER THE NE PORTION OF THE
CWA EARLIER. BEHIND THE COLD FRONT...A SURGE IN SURFACE WINDS WAS
ASSOCIATED WITH A RISING PRESSURE SURGE AS THIS LOW DEPARTED. SKIES
HAVE GENERALLY CLEARED AND VISIBILITIES IMPROVED DRAMATIC BEHIND THE
COLD FRONT. THE PRESSURE GRADIENT IS NOW IN THE PROCESS OF RELAXING
ALLOWING SURFACE WINDS TO DECREASE FOR THE REST OF THE OVERNIGHT.
EARLIER SHOWER ACTIVITY ALONG PORTIONS OF THE CENTRAL MD CHES BAY
ENDED AS WELL. WINDS SHOULD BACK FROM NORTHERLY TO MORE WESTERLY BY
DAYBREAK SATURDAY.
TODAY...HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE MID-ATLANTIC
REGION TODAY. DRY WEATHER WITH MOSTLY SUNNY SKIES WILL PREVAIL. BUT
TEMPERATURES ALOFT AT 850 HPA WITH COLD ADVECTION WILL BE 6-8 DEGC
COOLER THAN YESTERDAY. IN AREAS THAT WERE NOT IN YESTERDAYS MARITIME
WEDGE OF COOL AIR...MAX TEMPS THIS AFTERNOON WILL BE 10-15 DEGF
COOLER THAN YESTERDAY. IN THOSE AREA THAT WERE IN THE COOL
WEDGE...MAX TEMPS WILL ACTUALLY BE A TAD WARMER THAN YESTERDAY...
OWING TO AMPLE SUNSHINE. OVER TEMPERATURES TODAY WILL BE NEAR OR
EVEN SLIGHTLY ABOVE SEASONAL NORMALS. SCATTERED DIURNALLY DRIVEN
CUMULUS WILL IMPACT MOST AREAS BETWEEN ABOUT NOON AND 5 PM. DURING
THE MORNING WINDS WILL BE NORTHWEST OR WEST. TYPICALLY WITH WESTERLY
WINDS...A LEE TROUGH WILL DEVELOP ALONG THE APPALACHIANS...AND THIS
IS SHOWN IN THE 00Z NAM MODEL NICELY. THUS...WINDS MORE WESTERLY
WEST OF THE BLUE RIDGE...AND BACKED MORE TO THE SOUTHWEST EAST OF
THE BLUE RIDGE. TEMPERATURES ON THE NORTH AND WEST SIDES OF THE
TROUGH WILL BE SLIGHTLY COOLER...EAST AND SOUTH SLIGHTLY WARMER.
TONIGHT...EARLIER LOW PRESSURE TROUGH WILL MOVE EAST OF THE AREA
DURING THE EVENING...AS SHOWN IN 00Z NAM GUIDANCE...WITH WEAK HIGH
PRESSURE BUILDING INTO THE AREA DURING THE OVERNIGHT. WINDS LIGHT
OVERNIGHT WITH A WEST TO NW COMPONENT INDICATED IN GUIDANCE.
TEMPERATURES EXPECTED TO BE SEASONAL NORMALS AS WELL AND LEANED MORE
ON THE MET GUIDANCE VALUES.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE BUILDS ACROSS THE MIDDLE ATLANTIC ON SUNDAY
AND OFF THE COAST BY SUNDAY NIGHT. MILDER TEMPERATURES IN THE 60S TO
LOWER 70S CAN BE EXPECTED FOR AFTERNOON HIGH TEMPERATURES. THE
WARMEST CONDITIONS WILL BE FOUND ACROSS CENTRAL VIRGINIA...COOLEST
NEAR THE MASON DIXON LINE.
LOW LEVEL WINDS WILL SHIFT TO THE EAST AND SOUTHEAST LATER SUNDAY
INTO MONDAY AS HIGH PRESSURE REMAINS OFF THE COAST. THIS WILL HELP
DRAW MOISTURE INTO THE FORECAST AREA. MOSTLY CLOUDY CONDITIONS ARE
EXPECTED DURING THE DAY. TEMPERATURES ARE STILL EXPECTED TO BE
SLIGHTLY ABOVE NORMAL. AN AREA OF LOW PRESSURE WILL TRACK NORTHEAST
ALONG THE CAROLINA COASTLINE DURING THIS TIME FRAME. THE BULK OF THE
RAINFALL ASSOCIATED WITH THIS FEATURE WILL REMAIN TO OUR SOUTH YET
SOME LIGHT RAIN/SHOWERS MAY STILL BE POSSIBLE OVER SOUTHERN PORTIONS
OF THE CWFA. RAINFALL AMOUNTS WILL BE LIGHT. MOSTLY CLOUDY SKIES AND
LOW LEVEL MOISTURE WILL HELP KEEP OVERNIGHT TEMPERATURES ON THE MILD
SIDE MONDAY NIGHT INTO EARLY TUESDAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
TEMPERATURES WILL MODERATE WELL INTO THE 70S TUESDAY AND APPROACHING
THE UPPER 70S TO LOWER 80S ON WEDNESDAY. ANOTHER FRONTAL BOUNDARY
WILL GRADUALLY SAG SOUTH INTO AT LEAST THE NORTHERN EXTENT OF OUR
FORECAST AREA BY MID WEEK. THIS WILL BRING CHANCES FOR SCATTERED
SHOWERS AND THUNDERSTORMS ESPECIALLY NEAR THE MASON DIXON LINE BUT
LOCATION WILL BE DEPENDENT ON HOW FAR SOUTH THE BOUNDARY CAN SINK. A
STRONGER COLD FRONT IS PROGGED TO PUSH EAST ACROSS THE FORECAST AREA
LATE THURSDAY INTO FRIDAY BRINGING WITH IT MORE WIDESPREAD COVERAGE
OF SHOWERS AND ISOLATED THUNDERSTORMS. WILL GO LIKELY ON POPS FOR
THIS EVENT.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
EXPECT VFR CONDITIONS THROUGH SUNDAY. EARLIER NORTHERLY WIND SURGE
HAS PASSED...AND EXPECT WINDS TO BE FROM A NW TO WEST COMPONENT
TODAY.
MOSTLY VFR EXPECTED SUNDAY FOLLOWED BY DECREASING CIGS AND VSBYS
MONDAY. SOME LIGHT RAIN/SHOWERS COULD IMPACT THE TERMINALS MONDAY.
ANOTHER FRONTAL BOUNDARY MAY SAG SOUTH ACROSS THE MASON DIXON LINE
FOR THE MIDDLE OF THE WEEK. A MORE SUBSTANTIAL FRONTAL PASSAGE WILL
OCCUR LATE THURSDAY OR FRIDAY WITH WIDESPREAD SHOWERS/ISOLATED
THUNDERSTORMS EXPECTED.
&&
.MARINE...
UPDATE...ON SECOND THOUGHT FOR TODAY...HAVE DECIDED AFTER LOOKING
AT MORE GUIDANCE TO CANCEL THE SMALL CRAFT ADVISORY WE HAD UP FOR
THIS AFTERNOON. THE 00Z NAM/GFS BOTH SHOW A LEE TROUGH WHICH WILL
HELP KNOCK DOWN WINDS. LATEST RAP AND 3KM HRRR ALSO SHOW RATHER
CHAOTIC WINDS ON THE WATERS FOR TODAY. SO WILL DROP MENTION OF THE
AFTERNOON SCA IN THE 430 UPDATE. THIS ALSO GOES ALONG WITH
DROPPING THE SCA THAT HAD BEEN UP THROUGH 6AM.
HIGH PRES BUILDS IN TONIGHT...AND THE PRESSURE GRADIENT WILL
RELAX...DO NOT EXPECT ANY SCA HEADLINES FOR TONIGHT.
WINDS WILL LIKELY REMAIN BELOW SCA LEVELS SUNDAY BUT APPROACH
CRITERIA MONDAY MORNING AS SOUTHERLY CHANNELING DEVELOPS. WINDS
REMAIN BELOW SCA LEVELS THROUGH MID WEEK FOLLOWED BY INCREASING
SOUTHERLY FLOW AHEAD OF THE NEXT FRONTAL PASSAGE LATE IN THE WEEK.
SMALL CRAFT CONDITIONS WILL LIKELY RETURN TO THE WATERS THURSDAY
AND ESPECIALLY FRIDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMZ
NEAR TERM...SMZ
SHORT TERM...KRW
LONG TERM...KRW
AVIATION...KRW/SMZ
MARINE...KRW/SMZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 PM EDT SUN APR 14 2013
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 428 PM EDT SUN APR 14 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOWLY RETREATING
CLOSED LO OVER SE CANADA GIVING WAY TO SHRTWV RDGING INTO THE GREAT
LKS. WITH SFC RDG AXIS/LLVL DRY AIR SHOWN ON THE 12Z GRB RAOB UNDER
THE UPR RDGING /H925-85 DEWPTS DOWN TO -12 TO -13C/...QUIET WX IS
CURRENTLY IN PLACE OVER UPR MI. BUT MID/HI CLDS IN ADVANCE OF POTENT
NEGATIVELY TILTED SHRTWV FOLLOWING THIS RDG INTO THE NRN PLAINS ARE
SPREADING INTO THE UPR LKS. 00Z-12Z H3 HGT FALLS WERE UP TO 150M
OVER THE NRN ROCKIES/PLAINS IN ADVANCE OF THIS DISTURBANCE. LEADING
EDGE OF BAND OF WAD PCPN THAT CORRESPONDS BEST WITH SHARPER PRES
GRADIENT/ ISENTROPIC ASCENT SHOWN ON THE 290-295K ISENTROPIC SFCS
/H85-75/ IS ADVANCING NEWD THRU WI AND HAS REACHED MNM THIS AFTN.
PCPN WAS FALLING AS SN AT THE LEADING EDGE OF THIS PCPN BAND...BUT
HAS CHANGED TO FZRA/RA ON THE SRN EDGE. THE BAND IS THINNEST OVER
THE E HALF OF WI...AND PCPN HAS ENDED S OF GRB. THERE WERE ALSO
SOME TS THIS MRNG AS FAR N AS IOWA NEAR H85 WARM FNT AND AT NOSE OF
65KT H85 SW LLJ SHOWN S OF THE WARM FNT AT TOPEKA KS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN TIMING/TRENDS AND
PTYPE AS WELL AS QPF.
LATE THIS AFTN...SLOWED DOWN FCST ARRIVAL OF PCPN TO ACCOUNT FOR
DRYNESS OF AIRMASS IN THE UPR GRT LKS AS WELL AS LOCATION OF BETTER
ISENTROPIC ASCENT SO FAR TO THE S. BUT ARRIVAL OF SHARPER PRES
GRADIENT/LIFT SHOWN ON THE NAM FCST 290-295K ISENTROPIC SFCS SUGGEST
PCPN WL BEGIN IN MNM COUNTY BY 21Z. FCST SDNGS/SFC OBS TO THE S SUG
BULK OF PCPN AT THE PCPN ONSET WL FALL AS SN BEFORE MIXING WITH
SLEET AND PSBLY RA OVER THE FAR S AT MNM AS ELEVATED WRMG PUSHES
TEMPS IN THE H8-75 LYR ABV ZERO. THERE COULD BE SOME SN ACCUMS UP TO
AN INCH NEAR THE WI BORDER OVER THE HIER TERRAIN W OF IMT.
TNGT...POTENT NEGATIVELY TILTED SHRTWV/SFC LO OVER SDAKOTA AT 00Z IS
FCST TO LIFT NE INTO NCENTRAL MN BY 12Z MON AND BECOME CUTOFF.
SHARPER H85-7 FGEN/MSTR CNVGC ASSOCIATED WITH H85 SE WINDS INCRSG UP
TO 50KTS BY 00Z AHEAD OF WARM FNT AS WELL AS MOST IMPRESSIVE H7 UVV
UNDER SHARPER DEEP LYR QVECTOR CNVGC OVER THE W CLOSER TO APRCHG
SHRTWV WARRANTS HIER POPS OVER THE W THIS EVNG...WITH A MORE NARROW
BAND OF LIGHTER PCPN PASSING THRU THE ERN ZNS AS SHOWN BY HIER RES
MODELS. AS THE SHRTWV SHIFTS FARTHER E AND ACCOMPANYING WARM
CONVEYOR BELT MSTR RIBBON UNDER IMPRESSIVE UPR DVGC AHEAD OF H3 JET
MAX SHIFTING ARND THE SRN FLANK OF THE CLOSED LO IN MN SHIFTS TO THE
E...HIER POPS WL ARRIVE OVER THE E AS WELL AFT 06Z AT NOSE OF
VEERING H85 WINDS TO S AND INCRSG TO 60KTS LIFTING PWAT 0.75 INCH TO
1 INCH...OR ALMOST 200 PCT OF NORMAL. THESE VIGOROUS DYNAMICS/
MOISTENING JUSTIFY QPF NEAR 1 INCH OVER THE W HALF...BUT THERE WL BE
LOWER TOTALS OVER THE E HALF BECAUSE THE WARM CONVEYOR BELT MSTR WL
MOVE STEADILY TO THE E AND LIMIT RESIDENCE TIME OF ANY HEAVIER RA.
RUNOFF FM THE HEAVY RA OVER THE W HALF IN THE PRESENCE OF LINGERING
SN PILES MAY CAUSE SOME PONDING OF WATER. MAINTAINED MENTION OF
ELEVATED TS OVER THE SE AT THE NOSE OF THIS LLJ AND WHERE H875 TEMPS
TO THE N OF SFC WARM FNT ARE PROGGED TO RISE NEAR 10C. ARRIVAL OF
VIGOROUS DRY SLOTTING IN THE JET SURGE WL DIMINISH THE PCPN LATE
TNGT SW TO NE...WITH BACK EDGE OF WARM CONVEYOR BELT MSTR NEARING
ERY-MSQ TOWARD 12Z. IN FACT...FCST SDNGS INDICATE THERE MAY BE SOME
CLRG OVER THE SW LATE WITH VIGOROUS LLVL DRYING.
MAIN FCST CONCERNS TNGT ARE FOCUSED ON PTYPE AND POTENTIAL SN/ICE
ACCUMS. WITH THE VIGOROUS WAD...FCST SDNGS SHOW EXPANDING ELEVATED
WARM LYR ARRIVING S TO N...SO SN AT ONSET OF PCPN WL CHG TO RA. BEST
CHC FOR SEVERAL INCHES OF WET SNOW WL BE OVER THE HIER TERRAIN OF
THE KEWEENAW WHERE THE WARM AIR WL ARRIVE LATEST AND TEMPS STAYED A
BIT LOWER TDAY IN THE PRESENCE OF UPSLOPE COOLING OFF THE CHILLY
WATERS OF LK SUP. THERE WL BE SOME SLEET AS WELL AS EVAPORATIVE
COOLING ASSOCIATED WITH DRY AIR SHOWN ON THE 12Z GRB RAOB MAINTAINS
SUFFICIENTLY COLD TEMPS IN THE LYR BLO THE ELEVATED WARM NOSE FOR RA
DROPS TO REFREEZE INTO ICE PELLETS. BUT AS THIS LYR SATURATES AND
WARMS...SLEET SHOULD END AND GIVE WAY TO ONLY RA AS SFC TEMPS SLOWLY
RISE THRU THE 30S. THE BIG QUESTION IS HOW LONG SFC TEMPS WL BE NEAR
32 TO ALLOW FOR FZRA. EXPLICIT MODEL FCST SNDGS HAVE INDICATED FOR
SOME TIME THAT A PERIOD OF FZRA WL OCCUR. ATLHOUGH THE TIME OF YEAR
SHOULD RULE OUT FZRA AND SFC TEMPS HAVE RISEN WELL ABV 32 AT MOST
SPOTS THIS AFTN...LINGERING LO DEWPTS/POTENTIAL FOR EVAPORATE
COOLING AS WELL AS THE FCST SDNGS INDICATE THIS THREAT MIGHT BE REAL
MAINLY OVER THE HIER TERRAIN W OF MQT-IMT. THE NAM SHOWS LINGERING
AXIS OF LOWER DEWPTS IN THE H925 LYR IN THE ELY SFC FLOW N OF WARM
FNT. OPTED TO INCLUDE A MENTION OF FZRA THIS EVNG INTO THE EARLY
OVERNGT OVER THE HIER TERRAIN OF THE NW WHERE UPSLOPE COOLING WL
KEEP TEMPS AT LEAST CLOSE TO 32 AFTER SUNSET.
CONSIDERING THE POTENTIAL FOR SOME LOCALLY HVY SN...-FZRA...AND
PONDING OF WATER ACCOMPANYING HEAVIER RA...OPTED TO ISSUE AN SPS FOR
THE W HALF OF THE CWA TO HIGHLIGHT THESE POSSIBLE HAZARDS.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 428 PM EDT SUN APR 14 2013
BY MON MORNING...THE STACKED LOW WILL BE OVER NRN MN...WITH THE
ASSOCIATED OCCLUDED FRONT NE OF THE CWA...ALLOWING THE DRY SLOT TO
QUICKLY COVER MUCH OF THE CWA BY MID MORNING. THE EXCEPTION TO THIS
WILL BE OVER THE WRN THIRD OF THE U.P. WHERE WRAP AROUND LOW LEVEL
MOISTURE WILL MOVE IN. MODELS HAVE BEEN TRENDING SLIGHTLY FARTHER E
WITH THE SFC LOW AS IT MOVES ACROSS THE MN ARROWHEAD AND FAR NRN
LAKE SUPERIOR...SO THE LOW LEVEL MOISTURE COVERAGE HAS ALSO BEEN
TRENDING FARTHER E. THE IMPACT OF THE LOW LEVEL MOISTURE WILL BE TO
ALLOW CONVECTIVE RAIN/SNOW SHOWERS DUE TO THE COLD AIR OVERHEAD IN
PROXIMITY TO THE UPPER LOW AND STEEP LOW LEVEL LAPSE RATES. WITH
MOST MODELS SHOWING A COUPLE HUNDREDTHS OF AN INCH OF QPF OVER THE
WRN THIRD OF UPPER MI...THINK CHANCE POPS FROM PREVIOUS SHIFT COVERS
IT WELL. THE GOOD LOW LEVEL MIXING WILL ALSO ALLOW FOR MIXING OF
GUSTY WINDS TO THE SFC. THINK THAT MIXING TO AROUND 800MB AS SHOWN
BY MODEL SOUNDINGS SEEMS REALISTIC...AND WITH 800MB WINDS MON OF
AROUND 45KTS...COULD SEE SOME 40-45MPH GUSTS. EVEN THOUGH THE SYSTEM
IS WEAKENING...PRESSURE RISE/FALL COUPLET ORIENTATION WILL ENHANCE
THE GEOSTROPHIC WIND COMPONENT. DO NOT THINK CONDITIONS WARRANT WIND
ADVISORY...BUT WILL BE BORDERLINE. ANOTHER FACTOR WITH THE GOOD
MIXING IS THAT SFC TEMPS WILL BE ABLE TO WARM CONSIDERABLY...AND
SHOULD REACH AT LEAST 40 EVERYWHERE...BUT IN AREAS THAT DO NOT SEE
THE LOW LEVEL MOISTURE /SCENTRAL AND ERN U.P./ WILL GET UP TO AROUND
50. COULD SEE SOME LAKE EFFECT SNOW OVER THE FAR W ALONG AND BEHIND
THE SECONDARY COLD FRONT AS WINDS TURN NWLY...BUT COVERAGE SHOULD BE
LIMITED AT BEST.
RIDGING BUILD IN ON TUE AND TUE NIGHT...SO WILL SEE QUIET WEATHER.
GFS CONTINUES TO SHOW SOME QPF OVER THE WRN HALF OF UPPER MI
TUE...BUT GIVEN DOWNWARD MOTION WILL KEEP THE FORECAST DRY.
WED NIGHT AND THURSDAY...ATTENTION THEN TURNS TO A DEEP UPPER TROUGH
THAT WILL TRAVERSE THE MID SECTION OF THE COUNTRY FROM MID TO LATE
WEEK. THIS TROUGH RESULTS IN A SFC LOW MOVING THROUGH THE
REGION...ALTHOUGH THE EXACT TRACK REMAINS UNCERTAIN. DEFINITELY
FAVOR THE TRACK GIVEN BY THE ECMWF WHICH HAS MUCH BETTER CONTINUITY
IN BRINGING THE SFC LOW FROM NRN IL AT 06Z THU TO NEAR TRAVERSE CITY
MI BY 12Z THU THEN TO LAKE HURON BY 18Z THU. THE ECMWF HAS BEEN
TRENDING EVER SO SLIGHTLY WESTWARD WITH THE LOW TRACK...BUT NOT
NEARLY AS MUCH AS THE GFS AND GEM WHICH HAVE SHOWN POOR RUN TO RUN
CONTINUITY AND NOW WITH THE LATEST RUNS ARE CLOSER TO THE ECMWF
SOLUTION. WITH THE ECMWF SOLUTION...AREAS NEAR LAKE MI AND OVER THE
ERN CWA WOULD BE FAVORED FOR MOSTLY RAIN...WITH THE DRY SLOT MOVING
IN BEFORE THE COLDER AIR CAN TURN THINGS TO SNOW. IN NCENTRAL AND
WRN UPPER MI...TEMPERATURES AND LOW TRACK WILL BE FAVORABLE FOR
HEAVY SNOW. IT IS IMPORTANT TO EMPHASIZE THAT THERE IS CONSIDERABLE
UNCERTAINTY WITH THE TRACK OF THIS SYSTEM...WITH A WIDE RANGE OF
PRECIPITATION POSSIBILITIES DEPENDING ON THE TRACK...RANGING FROM HEAVY
SNOW TO MOSTLY RAIN AND WARMER TEMPERATURES OVER THE DEEP SNOWPACK
ACROSS THE AREA. WHATEVER SCENARIO PLAYS OUT...IT BEARS CLOSELY
WATCHING THIS SYSTEM OVER THE NEXT FEW DAYS. WILL CONTINUE TO
MENTION THE POTENTIAL FOR HEAVY SNOW IN THE HAZARDOUS WEATHER
OUTLOOK.
REGARDLESS OF THE EXACT TRACK...850MB TEMPS DROP TO -10 TO -14C PER
THE GFS AND ECMWF BY 18Z FRI WHICH COMBINED WITH THE UPPER TROUGH AND
N-NW FLOW SHOULD BE ENOUGH FOR AT LEAST SOME LAKE ENHANCED SNOW
FRIDAY INTO SATURDAY MORNING. THIS WILL ALSO ALLOW FOR TEMPS TO BE
WELL BELOW NORMAL ONCE AGAIN WITH TEMPS LIKELY STRUGGLING TO REACH
THE MID 30S SATURDAY. LOTS OF UNCERTAINTY NEXT SUN GIVEN MODEL
DISAGREEMENT AND RUN TO RUN DISCONTINUITY...SO WILL JUST USE A
CONSENSUS OF GUIDANCE AND FOCUS ON SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 739 PM EDT SUN APR 14 2013
LOW PRES TRACKING NE FROM SW MN WILL BRING A PERIOD OF WINTRY
WEATHER TO KIWD/KCMX/KSAW THIS EVENING. IFR CONDITIONS SHOULD
PREVAIL THIS EVENING AT KIWD WHILE KCMX/KSAW SHOULD SEE CONDITIONS
FALL TO LIFR WITH UPSLOPING E TO SE WINDS. AS NOSE OF WARMER AIR
ALOFT SURGES N...SNOW WILL LIKELY MIX WITH SLEET/RAIN AT KIWD/KSAW
IN THE EVENING WITH CHANGE TO ALL RAIN AT THE END OF THE EVENING. AT
KCMX...COLUMN WILL REMAIN COLDER LONGER...RESULTING IN SLEET/RAIN
MIXING WITH THE SNOW LATE EVENING AND A CHANGE TO RAIN OVERNIGHT. AS
PCPN CHANGES TO RAIN...CONDITIONS WILL LIKELY IMPROVE TO LOW MVFR AT
KIWD. HOWEVER...UPSLOPE WINDS SHOULD WORK TO MAINTAIN IFR/LIFR
CONDITIONS AT KCMX/KSAW. ALTHOUGH LOW-LEVEL JET OF 50-60KT AT 2-5KFT
WILL BE SHIFTING ACROSS THE AREA TONIGHT...DID NOT INCLUDE LLWS
SINCE GUSTY SFC WINDS ARE EXPECTED. MOISTURE WRAPPING AROUND SFC LOW
LIFTING THRU NRN MN INTO ONTARIO SHOULD RESULT IN MVFR CIGS THRU THE
DAY MON AT KIWD ALONG WITH THE POTENTIAL FOR OCNL -SHRASN. DRY SLOT
WORKING THRU THE AREA E OF KIWD SHOULD RESULT IN A PERIOD OF VFR
CONDITIONS AT KCMX/KSAW IN THE MORNING. MVFR CIGS MAY RETURN TO KCMX
IN THE AFTN AS MOISTURE WRAPS BACK INTO THE AREA. GUSTY SW WINDS ARE
EXPECTED MON AS THE SFC LOW LIFTS BY TO THE NW OF THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT SUN APR 14 2013
EXPECT ENE WINDS TO 25 TO 30 KTS TO INCREASE TO GALES TO 35 KTS OVER
MUCH OF THE LAKE TONIGHT AND VEER SE AS VIGOROUS LO PRES NOW IN THE
NORTHERN PLAINS MOVES THRU MINNESOTA AND THE PRES GRADIENT TIGHTENS
SHARPLY. THE STRONGEST WINDS WL OCCUR IN AREAS WHERE TOPOGRAPHY
ENHANCES THE E TO SE WINDS. LATER TONIGHT...WINDS OVER THE W HALF
WILL DIMINISH WITH THE CLOSER APPROACH OF THE LOW AND A WEAKER PRES
GRADIENT. MAINTAINED GALE WARNINGS ISSUED EARLIER FOR LATE TODAY
THRU TONIGHT.
AS THE LOW PRESSURE SYSTEM MOVES FROM NORTHERN MN MONDAY MORNING TO
JAMES BY BY TUESDAY MORNING...STRONG SOUTHWEST WINDS MAY GUST TO 35
KNOTS OVER THE WESTERN HALF OF LAKE SUPERIOR MONDAY INTO MONDAY
NIGHT. WINDS THEN DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING
OUT OF THE N WEDNESDAY NIGHT INTO FRIDAY WHEN GALES MAY BE POSSIBLE
AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 8 AM EDT MONDAY FOR LSZ266-267.
GALE WARNING UNTIL 4 AM EDT /3 AM CDT/ MONDAY FOR LSZ162.
GALE WARNING FROM 1 AM TO 5 AM EDT MONDAY FOR LSZ244>246-264-265.
GALE WARNING UNTIL 4 AM EDT MONDAY FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
431 PM EDT SUN APR 14 2013
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 428 PM EDT SUN APR 14 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOWLY RETREATING
CLOSED LO OVER SE CANADA GIVING WAY TO SHRTWV RDGING INTO THE GREAT
LKS. WITH SFC RDG AXIS/LLVL DRY AIR SHOWN ON THE 12Z GRB RAOB UNDER
THE UPR RDGING /H925-85 DEWPTS DOWN TO -12 TO -13C/...QUIET WX IS
CURRENTLY IN PLACE OVER UPR MI. BUT MID/HI CLDS IN ADVANCE OF POTENT
NEGATIVELY TILTED SHRTWV FOLLOWING THIS RDG INTO THE NRN PLAINS ARE
SPREADING INTO THE UPR LKS. 00Z-12Z H3 HGT FALLS WERE UP TO 150M
OVER THE NRN ROCKIES/PLAINS IN ADVANCE OF THIS DISTURBANCE. LEADING
EDGE OF BAND OF WAD PCPN THAT CORRESPONDS BEST WITH SHARPER PRES
GRADIENT/ ISENTROPIC ASCENT SHOWN ON THE 290-295K ISENTROPIC SFCS
/H85-75/ IS ADVANCING NEWD THRU WI AND HAS REACHED MNM THIS AFTN.
PCPN WAS FALLING AS SN AT THE LEADING EDGE OF THIS PCPN BAND...BUT
HAS CHANGED TO FZRA/RA ON THE SRN EDGE. THE BAND IS THINNEST OVER
THE E HALF OF WI...AND PCPN HAS ENDED S OF GRB. THERE WERE ALSO
SOME TS THIS MRNG AS FAR N AS IOWA NEAR H85 WARM FNT AND AT NOSE OF
65KT H85 SW LLJ SHOWN S OF THE WARM FNT AT TOPEKA KS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN TIMING/TRENDS AND
PTYPE AS WELL AS QPF.
LATE THIS AFTN...SLOWED DOWN FCST ARRIVAL OF PCPN TO ACCOUNT FOR
DRYNESS OF AIRMASS IN THE UPR GRT LKS AS WELL AS LOCATION OF BETTER
ISENTROPIC ASCENT SO FAR TO THE S. BUT ARRIVAL OF SHARPER PRES
GRADIENT/LIFT SHOWN ON THE NAM FCST 290-295K ISENTROPIC SFCS SUGGEST
PCPN WL BEGIN IN MNM COUNTY BY 21Z. FCST SDNGS/SFC OBS TO THE S SUG
BULK OF PCPN AT THE PCPN ONSET WL FALL AS SN BEFORE MIXING WITH
SLEET AND PSBLY RA OVER THE FAR S AT MNM AS ELEVATED WRMG PUSHES
TEMPS IN THE H8-75 LYR ABV ZERO. THERE COULD BE SOME SN ACCUMS UP TO
AN INCH NEAR THE WI BORDER OVER THE HIER TERRAIN W OF IMT.
TNGT...POTENT NEGATIVELY TILTED SHRTWV/SFC LO OVER SDAKOTA AT 00Z IS
FCST TO LIFT NE INTO NCENTRAL MN BY 12Z MON AND BECOME CUTOFF.
SHARPER H85-7 FGEN/MSTR CNVGC ASSOCIATED WITH H85 SE WINDS INCRSG UP
TO 50KTS BY 00Z AHEAD OF WARM FNT AS WELL AS MOST IMPRESSIVE H7 UVV
UNDER SHARPER DEEP LYR QVECTOR CNVGC OVER THE W CLOSER TO APRCHG
SHRTWV WARRANTS HIER POPS OVER THE W THIS EVNG...WITH A MORE NARROW
BAND OF LIGHTER PCPN PASSING THRU THE ERN ZNS AS SHOWN BY HIER RES
MODELS. AS THE SHRTWV SHIFTS FARTHER E AND ACCOMPANYING WARM
CONVEYOR BELT MSTR RIBBON UNDER IMPRESSIVE UPR DVGC AHEAD OF H3 JET
MAX SHIFTING ARND THE SRN FLANK OF THE CLOSED LO IN MN SHIFTS TO THE
E...HIER POPS WL ARRIVE OVER THE E AS WELL AFT 06Z AT NOSE OF
VEERING H85 WINDS TO S AND INCRSG TO 60KTS LIFTING PWAT 0.75 INCH TO
1 INCH...OR ALMOST 200 PCT OF NORMAL. THESE VIGOROUS DYNAMICS/
MOISTENING JUSTIFY QPF NEAR 1 INCH OVER THE W HALF...BUT THERE WL BE
LOWER TOTALS OVER THE E HALF BECAUSE THE WARM CONVEYOR BELT MSTR WL
MOVE STEADILY TO THE E AND LIMIT RESIDENCE TIME OF ANY HEAVIER RA.
RUNOFF FM THE HEAVY RA OVER THE W HALF IN THE PRESENCE OF LINGERING
SN PILES MAY CAUSE SOME PONDING OF WATER. MAINTAINED MENTION OF
ELEVATED TS OVER THE SE AT THE NOSE OF THIS LLJ AND WHERE H875 TEMPS
TO THE N OF SFC WARM FNT ARE PROGGED TO RISE NEAR 10C. ARRIVAL OF
VIGOROUS DRY SLOTTING IN THE JET SURGE WL DIMINISH THE PCPN LATE
TNGT SW TO NE...WITH BACK EDGE OF WARM CONVEYOR BELT MSTR NEARING
ERY-MSQ TOWARD 12Z. IN FACT...FCST SDNGS INDICATE THERE MAY BE SOME
CLRG OVER THE SW LATE WITH VIGOROUS LLVL DRYING.
MAIN FCST CONCERNS TNGT ARE FOCUSED ON PTYPE AND POTENTIAL SN/ICE
ACCUMS. WITH THE VIGOROUS WAD...FCST SDNGS SHOW EXPANDING ELEVATED
WARM LYR ARRIVING S TO N...SO SN AT ONSET OF PCPN WL CHG TO RA. BEST
CHC FOR SEVERAL INCHES OF WET SNOW WL BE OVER THE HIER TERRAIN OF
THE KEWEENAW WHERE THE WARM AIR WL ARRIVE LATEST AND TEMPS STAYED A
BIT LOWER TDAY IN THE PRESENCE OF UPSLOPE COOLING OFF THE CHILLY
WATERS OF LK SUP. THERE WL BE SOME SLEET AS WELL AS EVAPORATIVE
COOLING ASSOCIATED WITH DRY AIR SHOWN ON THE 12Z GRB RAOB MAINTAINS
SUFFICIENTLY COLD TEMPS IN THE LYR BLO THE ELEVATED WARM NOSE FOR RA
DROPS TO REFREEZE INTO ICE PELLETS. BUT AS THIS LYR SATURATES AND
WARMS...SLEET SHOULD END AND GIVE WAY TO ONLY RA AS SFC TEMPS SLOWLY
RISE THRU THE 30S. THE BIG QUESTION IS HOW LONG SFC TEMPS WL BE NEAR
32 TO ALLOW FOR FZRA. EXPLICIT MODEL FCST SNDGS HAVE INDICATED FOR
SOME TIME THAT A PERIOD OF FZRA WL OCCUR. ATLHOUGH THE TIME OF YEAR
SHOULD RULE OUT FZRA AND SFC TEMPS HAVE RISEN WELL ABV 32 AT MOST
SPOTS THIS AFTN...LINGERING LO DEWPTS/POTENTIAL FOR EVAPORATE
COOLING AS WELL AS THE FCST SDNGS INDICATE THIS THREAT MIGHT BE REAL
MAINLY OVER THE HIER TERRAIN W OF MQT-IMT. THE NAM SHOWS LINGERING
AXIS OF LOWER DEWPTS IN THE H925 LYR IN THE ELY SFC FLOW N OF WARM
FNT. OPTED TO INCLUDE A MENTION OF FZRA THIS EVNG INTO THE EARLY
OVERNGT OVER THE HIER TERRAIN OF THE NW WHERE UPSLOPE COOLING WL
KEEP TEMPS AT LEAST CLOSE TO 32 AFTER SUNSET.
CONSIDERING THE POTENTIAL FOR SOME LOCALLY HVY SN...-FZRA...AND
PONDING OF WATER ACCOMPANYING HEAVIER RA...OPTED TO ISSUE AN SPS FOR
THE W HALF OF THE CWA TO HIGHLIGHT THESE POSSIBLE HAZARDS.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 428 PM EDT SUN APR 14 2013
BY MON MORNING...THE STACKED LOW WILL BE OVER NRN MN...WITH THE
ASSOCIATED OCCLUDED FRONT NE OF THE CWA...ALLOWING THE DRY SLOT TO
QUICKLY COVER MUCH OF THE CWA BY MID MORNING. THE EXCEPTION TO THIS
WILL BE OVER THE WRN THIRD OF THE U.P. WHERE WRAP AROUND LOW LEVEL
MOISTURE WILL MOVE IN. MODELS HAVE BEEN TRENDING SLIGHTLY FARTHER E
WITH THE SFC LOW AS IT MOVES ACROSS THE MN ARROWHEAD AND FAR NRN
LAKE SUPERIOR...SO THE LOW LEVEL MOISTURE COVERAGE HAS ALSO BEEN
TRENDING FARTHER E. THE IMPACT OF THE LOW LEVEL MOISTURE WILL BE TO
ALLOW CONVECTIVE RAIN/SNOW SHOWERS DUE TO THE COLD AIR OVERHEAD IN
PROXIMITY TO THE UPPER LOW AND STEEP LOW LEVEL LAPSE RATES. WITH
MOST MODELS SHOWING A COUPLE HUNDREDTHS OF AN INCH OF QPF OVER THE
WRN THIRD OF UPPER MI...THINK CHANCE POPS FROM PREVIOUS SHIFT COVERS
IT WELL. THE GOOD LOW LEVEL MIXING WILL ALSO ALLOW FOR MIXING OF
GUSTY WINDS TO THE SFC. THINK THAT MIXING TO AROUND 800MB AS SHOWN
BY MODEL SOUNDINGS SEEMS REALISTIC...AND WITH 800MB WINDS MON OF
AROUND 45KTS...COULD SEE SOME 40-45MPH GUSTS. EVEN THOUGH THE SYSTEM
IS WEAKENING...PRESSURE RISE/FALL COUPLET ORIENTATION WILL ENHANCE
THE GEOSTROPHIC WIND COMPONENT. DO NOT THINK CONDITIONS WARRANT WIND
ADVISORY...BUT WILL BE BORDERLINE. ANOTHER FACTOR WITH THE GOOD
MIXING IS THAT SFC TEMPS WILL BE ABLE TO WARM CONSIDERABLY...AND
SHOULD REACH AT LEAST 40 EVERYWHERE...BUT IN AREAS THAT DO NOT SEE
THE LOW LEVEL MOISTURE /SCENTRAL AND ERN U.P./ WILL GET UP TO AROUND
50. COULD SEE SOME LAKE EFFECT SNOW OVER THE FAR W ALONG AND BEHIND
THE SECONDARY COLD FRONT AS WINDS TURN NWLY...BUT COVERAGE SHOULD BE
LIMITED AT BEST.
RIDGING BUILD IN ON TUE AND TUE NIGHT...SO WILL SEE QUIET WEATHER.
GFS CONTINUES TO SHOW SOME QPF OVER THE WRN HALF OF UPPER MI
TUE...BUT GIVEN DOWNWARD MOTION WILL KEEP THE FORECAST DRY.
WED NIGHT AND THURSDAY...ATTENTION THEN TURNS TO A DEEP UPPER TROUGH
THAT WILL TRAVERSE THE MID SECTION OF THE COUNTRY FROM MID TO LATE
WEEK. THIS TROUGH RESULTS IN A SFC LOW MOVING THROUGH THE
REGION...ALTHOUGH THE EXACT TRACK REMAINS UNCERTAIN. DEFINITELY
FAVOR THE TRACK GIVEN BY THE ECMWF WHICH HAS MUCH BETTER CONTINUITY
IN BRINGING THE SFC LOW FROM NRN IL AT 06Z THU TO NEAR TRAVERSE CITY
MI BY 12Z THU THEN TO LAKE HURON BY 18Z THU. THE ECMWF HAS BEEN
TRENDING EVER SO SLIGHTLY WESTWARD WITH THE LOW TRACK...BUT NOT
NEARLY AS MUCH AS THE GFS AND GEM WHICH HAVE SHOWN POOR RUN TO RUN
CONTINUITY AND NOW WITH THE LATEST RUNS ARE CLOSER TO THE ECMWF
SOLUTION. WITH THE ECMWF SOLUTION...AREAS NEAR LAKE MI AND OVER THE
ERN CWA WOULD BE FAVORED FOR MOSTLY RAIN...WITH THE DRY SLOT MOVING
IN BEFORE THE COLDER AIR CAN TURN THINGS TO SNOW. IN NCENTRAL AND
WRN UPPER MI...TEMPERATURES AND LOW TRACK WILL BE FAVORABLE FOR
HEAVY SNOW. IT IS IMPORTANT TO EMPHASIZE THAT THERE IS CONSIDERABLE
UNCERTAINTY WITH THE TRACK OF THIS SYSTEM...WITH A WIDE RANGE OF
PRECIPITATION POSSIBILITIES DEPENDING ON THE TRACK...RANGING FROM HEAVY
SNOW TO MOSTLY RAIN AND WARMER TEMPERATURES OVER THE DEEP SNOWPACK
ACROSS THE AREA. WHATEVER SCENARIO PLAYS OUT...IT BEARS CLOSELY
WATCHING THIS SYSTEM OVER THE NEXT FEW DAYS. WILL CONTINUE TO
MENTION THE POTENTIAL FOR HEAVY SNOW IN THE HAZARDOUS WEATHER
OUTLOOK.
REGARDLESS OF THE EXACT TRACK...850MB TEMPS DROP TO -10 TO -14C PER
THE GFS AND ECMWF BY 18Z FRI WHICH COMBINED WITH THE UPPER TROUGH AND
N-NW FLOW SHOULD BE ENOUGH FOR AT LEAST SOME LAKE ENHANCED SNOW
FRIDAY INTO SATURDAY MORNING. THIS WILL ALSO ALLOW FOR TEMPS TO BE
WELL BELOW NORMAL ONCE AGAIN WITH TEMPS LIKELY STRUGGLING TO REACH
THE MID 30S SATURDAY. LOTS OF UNCERTAINTY NEXT SUN GIVEN MODEL
DISAGREEMENT AND RUN TO RUN DISCONTINUITY...SO WILL JUST USE A
CONSENSUS OF GUIDANCE AND FOCUS ON SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 154 PM EDT SUN APR 14 2013
VERY DIFFICULT FORECAST UNFOLDING FOR ALL SITES TONIGHT AS A STRONG
LOW PRESSURE SYSTEM BRINGS A WINTRY MIX OF PRECIP ALONG WITH STRONG
WINDS.
KIWD...MID LEVEL CLOUDS WILL CONTINUE TO LOWER THIS AFTERNOON WHILE
UPSLOPE LOW CLOUDS MOVE OFFSHORE WITH WINDS FROM THE EAST.
PRECIPITATION IN THE FORM OF -SN SHOULD REACH THE TERMINAL AROUND
22Z AND FALL MODERATELY FROM THE START. EXPECT -SN TO GRADUALLY MIX
WITH PL AND RA THIS EVENING BEFORE BRIEFLY TURNING OVER TO ALL RA
LATE TONIGHT. STRONG ESE WINDS OF 20 KTS AND A FEW GUSTS OVER 30 KTS
WILL ALSO BE POSSIBLE. DID NOT INCLUDE ANY LLWS DUE TO GUSTY SFC
WINDS...BUT EXPECT WINDS APPROACHING 60KTS FROM THE SOUTH AT AROUND
3KFT.
KCMX...HIGH-END MVFR UPSLOPE STRATUS HAS KICKED IN THIS AFTERNOON
AND SHOULD GENERALLY REMAIN IN PLACE BEFORE THE MAIN SYNOPTIC
MOISTURE ARRIVES WITH -SN AROUND 00Z. AS WITH IWD...A GENERAL
TRANSITION FROM -SN TO -SNPLRA TO -RA SHOULD OCCUR OVERNIGHT. WINDS
COULD GET QUITE GUSTY LATE TONIGHT AS THE STRONGEST SFC PRESSURE
GRADIENT TRACKS OVER THE WEST HALF OF LAKE SUPERIOR. LOOK FOR A FEW
GUSTS UP TO 40 KTS.
AT KSAW...UPSLOPE CLOUDS SHOULD BE SHORT-LIVED AS WINDS VEER MORE
FROM THE EAST. SYNOPTIC PRECIP SHOULD ARRIVE AROUND 23Z AND WILL
FOLLOW THE SAME -SN TO -SNPLRA TO -RA TRANSITION AS IWD AND CMX.
UPSLOPE FLOW WITH ESE TO SE WINDS WILL BRING CIGS TO LIFR LEVELS
OVERNIGHT. THOUGH GUSTY WINDS ARE EXPECTED OVERNIGHT...MORE CONCERN
LIES WITH STRONG SW WINDS WITH GUSTS TO 35KTS MONDAY MORNING AS THE
DRY SECTOR OF THE SYSTEM ALLOWS FOR MORE MOMENTUM TRANSFER FROM
STRONG WINDS ALOFT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT SUN APR 14 2013
EXPECT ENE WINDS TO 25 TO 30 KTS TO INCREASE TO GALES TO 35 KTS OVER
MUCH OF THE LAKE TONIGHT AND VEER SE AS VIGOROUS LO PRES NOW IN THE
NORTHERN PLAINS MOVES THRU MINNESOTA AND THE PRES GRADIENT TIGHTENS
SHARPLY. THE STRONGEST WINDS WL OCCUR IN AREAS WHERE TOPOGRAPHY
ENHANCES THE E TO SE WINDS. LATER TONIGHT...WINDS OVER THE W HALF
WILL DIMINISH WITH THE CLOSER APPROACH OF THE LOW AND A WEAKER PRES
GRADIENT. MAINTAINED GALE WARNINGS ISSUED EARLIER FOR LATE TODAY
THRU TONIGHT.
AS THE LOW PRESSURE SYSTEM MOVES FROM NORTHERN MN MONDAY MORNING TO
JAMES BY BY TUESDAY MORNING...STRONG SOUTHWEST WINDS MAY GUST TO 35
KNOTS OVER THE WESTERN HALF OF LAKE SUPERIOR MONDAY INTO MONDAY
NIGHT. WINDS THEN DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING
OUT OF THE N WEDNESDAY NIGHT INTO FRIDAY WHEN GALES MAY BE POSSIBLE
AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 1 AM TO 8 AM EDT MONDAY FOR LSZ266-267.
GALE WARNING UNTIL 4 AM EDT /3 AM CDT/ MONDAY FOR LSZ162.
GALE WARNING FROM 1 AM TO 5 AM EDT MONDAY FOR LSZ244>246-264-265.
GALE WARNING FROM 8 PM THIS EVENING TO 4 AM EDT MONDAY FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...TK
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EDT SAT APR 13 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 415 PM EDT SAT APR 13 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS CLOSED LO
CENTERED OVER ONTARIO TO THE S OF PERSISTENT BLOCKING RDG OVER NE
CANADA IN PREVAILING NEGATIVE NAO PATTERN. WITH DEEP MSTR SHOWN ON
12Z INL/GRB RAOBS...CYC FLOW...H85-7 COLD POCKET WITH H85 TEMPS AS
LO AS -10C TO -12C OVER THE WRN CWA...AND SHRTWVS ROTATING ARND THE
MAIN CLOSED LO...CLDS AND SHSN HAVE LINGERED OVER UPR MI...E
SPECIALLY ALONG SFC LO PRES TROF ASSOCIATED WITH ONE OF THESE
SHRTWVS THAT IS CROSSING THE CWA EARLY THIS AFTN. TEMPS REMAIN WELL
BLO NORMAL FOR MID APRIL. OVER FAR WRN MN INTO THE NRN PLAINS...A
SFC RDG AXIS AND DRY MID LVL AIR SHOWN ON THE 12Z BISMARCK RAOB ARE
CAUSING DRY WX EVEN THOUGH SOME LO CLDS LINGER WITH MSTR TRAPPED BLO
INVRN BASE AT H8 SHOWN ON THE BISMARCK SOUNDING. ANOTHER POWERFUL
SHRTWV IS MOVING ONSHORE INTO THE PAC NW WITH 00Z-12Z H3-5 HGT FALLS
UP TO 150-200M.
MAIN FCST CONCERNS THRU TNGT ARE FOCUSED ON SHSN/CLD TRENDS AS THE
UPR LO OVER ONTARIO SLOWLY FILLS AND SHIFTS TO THE E. FOCUS ON
SUN/SUN NGT SHIFTS TO TIMING AND IMPACT OF SHRTWV NOW MOVING INTO
THE PAC NW.
LATE TODAY/TNGT...AS UPR LO IN ONTARIO SLOWLY WEAKENS...H5 HGT IS
PROGGED TO RISE 120M OVER UPR MI BTWN 00Z-12Z SUN UNDER VIGOROUS
DEEP LYR QVECTOR DVGC. AS THE CYC NW FLOW WEAKENS...EXPECT LINGERING
SHSN LATE THIS AFTN/EVNG TO DIMINISH STEADILY THRU THE NGT AND END
IN THE EARLY MRNG HRS ON SUN. WITH SOME CLRG LATE AT LEAST OVER THE
W AND CENTRL AND LGT WINDS UNDER THE SFC RDG AXIS...EXPECT TEMPS TO
FALL INTO THE TEENS...WELL BLO NORMAL FOR THE SEASON. WITH CLDS/LLVL
MSTR LINGERING LONGER IN A PERSISTENT NW FLOW OVER THE E...THOSE
AREAS WL BE WARMER.
SUN/SUN NGT...EXPECT A DRY START TO THE DAY WITH SFC HI PRES RDG
SLOWLY DEPARTING TO THE E. BUT ANY MRNG SUNSHINE WL QUICKLY FADE
BEHIND INCRSG CLDS AS VIGOROUS ISENTROPIC ASCENT/DEEPER MSTR/SW FLOW
ALF BTWN THE DEPARTING HI AND INCRSG NEGATIVELY TILTED SHRTWV/SFC LO
MOVING THRU THE NRN PLAINS AND TOWARD MN LATE IN THE DAY OVERSPREADS
UPR MI. AS UPR DVGC/BAND OF H85-7 FGEN AHEAD OF ATTENDANT WARM FNT
MOVES IN AFT 18Z...EXPECT PCPN TO OVERSPREAD THE CWA BY 00Z MON...
ESPECIALLY OVER THE W HALF CLOSER TO SHARPER DYNAMICS AND WHERE
MOISTENING/H85 MSTR CNVGC IS MOST IMPRESSIVE. PTYPE WL BE A CONCERN
SUN AFTN/EVNG. NAM/GFS FCST SDNGS INDICATE SATURATED TEMP PROFILE WL
AT LEAST INITIALLY BE COMPLETELY SUB ZERO...BUT THEN SHOW ELEVATED
WARM LYR ABV SUB ZERO NEAR SFC LYR. WITH ELEVATED WARMING INITIALLY
LIFTING TEMPS ABV 0C IN THE H8-75 LYR...SUSPECT SLEET WL MIX WITH
THE SN. THESE FCST SDNGS ALSO SUG PCPN MAY BE AT LEAST MIXED WITH
SOME FZRA FOR A TIME LATE IN THE AFTN/EVNG OVER AT LEAST THE HIER
TERRAIN OF THE W HALF AS THE ELEVATED WARM LYR DEEPENS AND TEMPS IN
THE LOWER LYR WARM TOO MUCH FOR DROPS TO REFREEZE. BUT THESE SDNGS
ALSO APPEAR TO UNDERDO THE SFC WARMING IN THE AFTN FOLLOWING AT
LEAST SOME MRNG SUNSHINE. WITH SOME LINGERING LLVL DRY AIR...
EVAPORATIVE COOLING COULD MAINTAIN SUB 32 NEAR SFC WBLB TEMPS. BUT
THE FCST NEAR SFC SE FLOW IN THE ABSENCE OF HI PRES CENTER OVER
ONTARIO AS WELL AS ARRIVAL OF PCPN AT MAX HEATING TIME THIS LATE IN
THE SEASON WOULD ALSO TEND TO MINIMIZE THIS THREAT. HIER GFS MOS
TEMPS SEEM MORE APPROPRIATE FOR THE TEMPS FCST THAN RAW MODEL
GUIDANCE. FOR NOW...WL FCST A SN/SLEET MIX AT THE ONSET
TRANSITIONING TO RA SUN EVNG AS MUCH WARMER/MSTR LLVL AIR SURGES
INTO THE UPR LKS ON THE HEELS OF H85 SW WINDS FCST UP TO 60-70KTS BY
06Z MON. EXPECT LITTLE IF ANY FALL OF TEMPS SUN NGT. THE NW CWA WL
HAVE THE BEST CHC FOR SEEING A LONGER PERIOD OF WINTRY PCPN WITH
H85-75 TEMPS REMAINING BLO 0C THERE FOR A LONGER TIME. NOT OUT OF
THE QUESTION ADVY SN MAY FALL OVER THE HIER TERRAIN OF THE KEWEENAW
SUN AFTN/EVNG. NEGATIVELY TILTED APPEARANCE OF SHRTWV/VERY DIFFLUENT
SW FLOW ALF/MSTR SURGE WITH FCST PWAT 0.75 TO 1 INCH SUN EVNG...OR
UP TO 200 PCT OF NORMAL...INDICATE QPF NEAR 1 INCH IN SOME PLACES IS
ON TRACK. RUNOFF FM THIS RA IN THE PRESENCE OF LINGERING SN PILES
MAY CAUSE SOME PONDING OF WATER. ALTHOUGH FCST H85-5 LAPSE RATES ARE
NOT MUCH MORE UNSTABLE THAN MOIST ADIABATIC...DECIDED TO INCLUDE
MENTION OF ELEVATED TS UNDER THE MOST IMPRESSIVE MOISTENING/AXIS OF
H85 LLJ GIVEN IMPRESSIVE DYNAMICS/NEGATIVE TILT OF SHRTWV. ARRIVAL
OF DRY SLOT SUN NGT WL DIMINISH POPS SW-NE AFTER THE EVNG. IN
FACT...FCST SDNGS INDICATE THERE MAY BE SOME CLRG OVER THE SW LATE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 415 PM EDT SAT APR 13 2013
ACTIVE PATTERN ACROSS THE CONUS CONTINUES INTO NEXT WEEKEND AS A
LARGE SCALE UPPER TROUGH MOVES FROM THE W COAST MON TO THE CENTRAL
CONUS BY NEXT SAT...WITH PIECES OF SMALLER SCALE ENERGY EJECTING OFF
THE TROUGH THROUGH THE REGION.
STARTING THE PERIOD OFF 12Z MON...A STACKED CLOSED LOW WILL BE OVER
NRN MN WITH AN OCCLUDED FRONT FROM THE LOW TO NRN LAKE
SUPERIOR...AND THE ASSOCIATED WARM FRONT EXTENDING E FROM NRN LAKE
SUPERIOR INTO ONTARIO AND THE COLD FRONT FROM NRN LAKE SUPERIOR TO
FAR ERN UPPER MI. AT THIS POINT...THE PRECIP THAT MOVED OVER THE CWA
AHEAD OF THE COLD FRONT WILL BE MOSTLY E OF THE CWA. THE DRY SLOT
BEHIND THE COLD FRONT WILL BRING VERY DRY AIR INITIALLY THROUGH MOST
OF THE SOUNDING...BUT WRAP AROUND LOW LEVEL MOISTURE BELOW 800MB WILL
RETURN TO AT LEAST NW UPPER MI /MODELS DIFFER ON THE AREAL EXTENT OF
THE MOISTURE/ AS THE LOW MOVES N OF LAKE SUPERIOR TO JAMES BAY BY
12Z TUE. THIS MAY RESULT IN SOME CONVECTIVE WINTRY MIX SHOWERS WHERE
THERE IS SUFFICIENT LOW LEVEL MOISTURE TO TAP INTO STEEP LOW LEVEL
LAPSE RATES...MAINLY MON INTO EARLY MON NIGHT. WILL INTRODUCE SOME
LOW END POPS FOR THIS POSSIBILITY TO NW UPPER MI. WITH THE STEEP LOW
LEVEL LAPSE RATES...WE SHOULD SEE MIXING TO AROUND 800MB ON
MON...AND WITH SW 800-900MB WINDS AOA 40KTS...IT WILL MAKE FOR GUSTY
SFC WINDS. MAY END UP NEEDING A WIND ADVISORY IN SOME
LOCATIONS...BUT TOO EARLY TO SAY WHERE AT THIS POINT AS MODELS DO
VARY IN STRENGTH AND LOCATION OF BEST LOW LEVEL WINDS. COULD ALSO
SEE SOME DOWNSLOPE ENHANCEMENT OF THE WINDS...ESPECIALLY NEAR LAKE
SUPERIOR ON MARQUETTE COUNTY WITH THE SW WINDS.
EVEN THOUGH 850MB TEMPS DROP BY 7C OR MORE FROM SUN NIGHT INTO
MON...SHOULD STILL BE ABLE TO SEE TEMPS WARM INTO THE 40S /EVEN
AROUND 50 OVER THE SCENTRAL CWA/ MON AFTERNOON DUE TO GOOD LOW LEVEL
MIXING MIXING. THESE WARMER TEMPS AND GUSTY WINDS...COMBINED WITH
SUNSHINE /ESPECIALLY OVER THE CENTRAL AND ERN CWA/ AND RAIN SUN
NIGHT...COULD SEE SOME MELTING OF THE SNOWPACK MON. PROBABLY WILL
NOT LOSE TOO MUCH SNOW PACK...BUT SOME REDUCTION IS CERTAINLY
POSSIBLE.
THE FRONTAL ZONE STALLS WELL TO OUR S THROUGH TUE NIGHT AS UPPER
RIDGING BUILDS OVER THE CWA. THE NRN STREAM JET THEN PUSHES THROUGH
THE CWA TUE NIGHT AS THE UPPER TROUGH OVER THE WRN CONUS SHARPENS UP
AND MOVES TO THE INTERMOUNTAIN WEST. NRN AND SRN STREAM INTERACTION
ALONG THE SRN END OF THE TROUGH WILL CAUSE IT TO DEEPEN AND SHARPEN
UP FURTHER AS IT MOVES E FROM HUDSON BAY TO MN TO TX BY 00Z FRI AS
UPPER RIDGING BUILDS E OF THE CWA. BY LATE WED...WITH THE PRESSURE
GRADIENT TIGHTENING...THE NOW PHASED SRN AND NRN JET STREAM ARCING
FROM W TO N OF THE CWA WILLS STRENGTHEN TO AOA 120KTS. THIS LEADS TO
RAPID SFC CYCLOGENESIS ALONG THE FRONTAL ZONE OVER MO. THE 850MB
FRONTAL ZONE WILL MOVE N INTO THE CWA WED...AND WHEN COMBINED WITH
THE FORCING FROM THE RIGHT ENTRANCE REGION OF THE UPPER JET WILL
LEAD TO PRECIP BY WED AFTERNOON. THE EXACT PLACEMENT AND TYPE OF
PRECIP REMAINS IN QUESTION DUE TO MODEL DISAGREEMENT...BUT GENERALLY
EXPECT SNOW OVER THE NW CWA AND RAIN OVER THE SE CWA...AND THIS
PRECIP SHOULD BE RELATIVELY MINOR ACCUMULATION WISE. PRECIP AMOUNTS
THEN BECOME MORE OF A CONCERN WED NIGHT AND THU AS THE SFC LOW MOVES
ACROSS LAKE MI AND LOWER MI LATE WED NIGHT INTO THU. THE 12Z/13 GFS
AND 00Z/13 ECMWF AGREE PRETTY WELL ON BRINGING THE SFC LOW ACROSS
NRN LOWER MI...BUT THE ECMWF IS ABOUT 6 HOURS FASTER THAN THE GFS AND
NOT AS DEEP WITH THE SFC LOW. OVERALL...A MINOR DIFFERENCE THIS FAR
OUT WITH THE VOLATILE NATURE OF THIS TYPE OF SYSTEM. THINK THAT
MODELS ARE NOT SETTLED AND THINGS WILL CHANGE OVER THE NEXT FEW
DAYS...BUT THE GENERAL IDEA SEEMS GOOD. AT THIS POINT...THERMAL
FIELDS ARE SIMILAR BETWEEN THE MODELS...WITH TEMPS COLD ENOUGH FOR
MAINLY SNOW OVER THE NW CWA...AND MAINLY RAIN OVER THE SE CWA...AT
LEAST UNTIL COLD AIR ARRIVES LATE THU INTO THU NIGHT. SIGNIFICANT
PRECIP AMOUNTS WILL BE POSSIBLE AS MODELS SHOW BETWEEN 0.3 INCHES
AND AROUND 1 INCH OF QPF...BUT VARY ON THE EXACT PLACEMENT OF THIS
PRECIP. STILL SOMETHING TO KEEP A CLOSE EYE ON.
BY LATE THU INTO FRI...ADDITIONAL ENERGY ROUNDING THE BASE OF THE
UPPER TROUGH CAUSES THE SFC LOW TO STALL SOME /OR MORE REDEVELOP ON
THE SW SIDE/. THE MAIN IMPACT THIS HAS ON OUR WEATHER IS TO KEEP
BETTER MOISTURE AND A SFC TROUGH STRETCHED BACK ACROSS LAKE SUPERIOR
AS THE UPPER TROUGH AND MUCH COLDER AIR MOVES ACROSS THE CWA. IF
THIS DOES INDEED COME TO REALITY...LAKE EFFECT SNOW WOULD BE THE
RESULT AS 850MB TEMPS FALL TO AROUND -13C AHEAD OF THE UPPER TROUGH.
LES SHOULD THEN CONTINUE INTO AT LEAST PART OF SATURDAY...BUT
CONFIDENCE IN OVERALL PATTERN DECLINES RAPIDLY THROUGH THE DAY SAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 147 PM EDT SAT APR 13 2013
LIGHT TO SOMETIMES MODERATE SNOW SHOWERS AFFECTING MAINLY IWD AND
SAW WILL DIMINISH THROUGHOUT THE AFTERNOON AS A TROUGH PASSES
THROUGH AND MOVE SOUTH OF THE AREA. EXPECT TEMPORARY VIS
RESTRICTIONS IN THE LIFR RANGE TO IMPROVE TO VFR VIS AT ALL SITES BY
LATER AFTERNOON. CLOUDS WILL START TO THIN OUT BY THIS
EVENING...THOUGH UPSLOPE FLOW AROUND CMX MAY KEEP A FEW HIGH-END
MVFR CLOUDS AROUND OVERNIGHT.
AN APPROACHING SYSTEM WILL BEGIN TO SPREAD MID-LEVEL CLOUDS ACROSS
UPPER MI LATE SUNDAY MORNING INTO THE AFTERNOON. IWD CAN EXPECT TO
SEE A MIX OF HEAVY SLEET...SNOW AND RAIN BY 21Z SUNDAY. CMX AND SAW
SHOULD SEE THE SAME BY 00Z MONDAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 415 PM EDT SAT APR 13 2013
NW WINDS UP TO 20-25 KTS OVER THE E HALF THIS EVENING WILL BECOME
LIGHT INTO SUN MORNING WITH ARRIVAL/PASSAGE OF HI PRES RIDGE AXIS.
AS THE NEXT LO PRES SYSTEM MOVES FROM THE NORTHERN PLAINS ON SUN
THRU MN SUN NIGHT AND THE PRES GRADIENT TIGHTENS...A STRONGER E WIND
VEERING SE UP TO 30 KTS WILL DEVELOP. OPTED TO ISSUE A GALE WATCH
FOR THE FAR W AND PORTIONS OF THE NCENTRAL AND E FOR LATE SUN/SUN
NIGHT WHERE THE EXPECTED FLOW IS ENHANCED BY TERRAIN INFLUENCES.
AS THE LOW PRESSURE SYSTEM MOVES FROM NORTHERN MN MONDAY MORNING TO
JAMES BY BY TUESDAY MORNING...STRONG SOUTHWEST WINDS MAY GUST TO 35
KNOTS OVER THE WESTERN HALF OF LAKE SUPERIOR MONDAY INTO MONDAY
NIGHT. WINDS THEN DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING
OUT OF THE N WEDNESDAY NIGHT INTO FRIDAY WHEN GALES MAY BE POSSIBLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM SUNDAY EVENING THROUGH LATE SUNDAY NIGHT FOR
LSZ264-266.
GALE WATCH FROM SUNDAY EVENING THROUGH LATE SUNDAY NIGHT FOR
LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...TK
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
149 PM EDT SAT APR 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT SAT APR 13 2013
LAKE ENHANCEMENT HAVING A TOUGH TIME STARTING EARLY THIS
MORNING...EXCEPT FOR A BAND JUST WEST OF IWD. SEEMS LIKE THE MAIN
PROBLEM WITH ORGANIZATION IS LACK OF ANY SIGNIFICANT LOW LEVEL
CONVERGENCE DUE THE VERY WEAK WIND FIELDS OVER THE LAND. AGAIN...THE
EXCEPTION TO THIS IS OVER THE WEST WHERE CYCLONIC NNE FLOW IS QUITE
FAVORABLE FOR THE IWD AREA. LOCAL HI RES NWP AND ALONG WITH THE RAP
AND HRRR SUGGEST THAT AS THE LES WILL BECOME A LITTLE MORE ORGANIZED
BETWEEN 09Z AND 12Z AS THE SFC TROUGH OVER THE LAKE MOVES SOUTH AND
THE INVERSION DEEPENS TO NEARLY 8000FT AS WEAK Q-VECTOR CONVERGENCE
ASSOCIATED WITH THE UPPER TROUGH AXIS MOVES ACROSS THE AREA.
STILL...DESPITE THE EXPECTED INCREASED COVERAGE OF SNOW THIS
MORNING...THE FACT REMAINS THAT THERE IS NOT MUCH SNOW ONGOING RIGHT
NOW OTHER THAN FAR WESTERN GOGEBIC COUNTY...AND ANY ADDITIONAL
ACCUMULATION IN THE KEWEENAW AND IN THE NORTH CENTRAL AREAS WILL
ONLY AMOUNT TO AN INCH OR TWO. AS SUCH...HAVE OPTED TO DROP THE
ADVISORY FOR THOSE AREAS BUT KEEP IT FOR THE GOGEBIC AND ONTONAGON
THROUGH 15Z. SINCE IT IS NOT REALLY SNOWING IN THE CURRENT ADVISORY
AREA EXCEPT ACROSS THE FAR WEST...IT JUST DOES NOT SEEM PRUDENT TO
KEEP THE ADVISORY AT THIS TIME FOR MQT/BARAGA AND THE KEWEENAW FOR
ONLY AN ADDITIONAL INCH OR TWO OF ADDITIONAL SNOW. WILL STILL
FORECAST 2 TO LOCALLY 4 INCHES IN THE IRONWOOD/PORCUPINE MTNS AREA
FOR THIS MORNING AS THE SOUNDINGS LOOK QUITE FAVORABLE FOR A BRIEF
PERIOD OF MODERATE SNOWFALL WITH THE RISING INVERSION AND BETTER
DENDRITIC SNOW GROWTH WITH THE TOP OF THE INVERSION AROUND -18C.
AS THE LOW PULLS OUT...RIDGING SHOULD SLOWLY BUILD IN FROM THE WEST
THIS AFTERNOON INTO TONIGHT. THIS SHOULD ALLOW THE LES TO END FROM
WEST TO EAST DURING THE DAY AND INTO THIS EVENING. ANY LES THIS
EVENING WOULD BE FOCUSED IN AREAS EAST OF MUNISING DUE TO THE NW PBL
FLOW. HOWEVER...DO NOT EXPECT THIS LES TO LAST TOO LONG DUE TO THE
RIDGE BUILDING AND AND RAPIDLY DIMINISHING MOISTURE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 440 AM EDT SAT APR 13 2013
NAM SHOWS A 500 MB SHORTWAVE RIDGE OVER THE UPPER GREAT LAKES 12Z
SUN WITH A CLOSED LOW OVER THE NORTHERN ROCKIES. THIS CLOSED LOW
QUICKLY MOVES INTO THE NORTHERN PLAINS LATE SUN AND AFFECTS THE
UPPER GREAT LAKES SUN NIGHT BEFORE IT HEADS NORTHEAST AND SHEARS OUT
TO THE NORTH ON MON. NAM BRINGS IN SOME DEEPER MOISTURE SUN
AFTERNOON ALONG WITH 850-500 MB Q-VECTOR CONVERGENCE WHICH REMAINS
THROUGH SUN NIGHT BEFORE AREA GETS DRY SLOTTED ON MON. NAM SHOWS
SOME STRONG ISENTROPIC LIFT ON I280K-I295K SURFACES WITH DEEP
MOISTURE SUN EVENING WITH THE LIFT MOVING OUT BY 12Z MON. GFS AND
ECMWF SHOW ABOUT THE SAME THING AS WELL. LOOKS LIKE MON THAT MOST OF
THE CWA GETS DRY SLOTTED AND SHOULD HAVE BREEZY CONDITIONS ON
MONDAY. WITH DRY SLOT MOVING THROUGH...THINK THERE WILL BE SOME
SUNSHINE WITH SW WINDS ALLOWING SOME DOWNSLOPING TO OCCUR. FOR THIS
REASON AND A BIT MORE SUNSHINE...RAISED SOME HIGH TEMPERATURES A BIT
AND COULD SEE A FEW 50S FOR HIGHS ON MONDAY.
LOOKED AT A FEW THINGS AND AGREE WITH PREVIOUS SHIFTS THINKING OF
HAVING SOME SLEET...RAIN AND SNOW MENTIONED FOR PCPN TYPE FOR SUN
AFTERNOON AND EVENING BEFORE WARMING TAKES PLACE TO SWITCH ALL THE
PCPN OVER TO ALL RAIN LATE SUN NIGHT INTO MONDAY. COULD SEE
0.50-0.90 OF QPF FROM THIS EVENT WHICH WILL EQUATE OUT TO LESS THAN
TWO INCHES OF TOTAL SNOW AS THINGS ARE WARMING. WITH PCPN HOLDING
OFF UNTIL SUNDAY AFTERNOON...THINGS WILL BE WARM ENOUGH TO NOT HAVE
THE PCPN BE ALL SNOW OR SLEET. KEPT CATEGORICAL POPS IN FOR SUNDAY
NIGHT AND THEN HAVE DRY SLOT MOVING INTO THE WEST AND CENTRAL AREAS
FOR MON.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW IN JAMES
BAY 12Z TUE WITH TROUGHING EXTENDING FROM THAT BACK TO THE NORTHERN
PLAINS AND SOUTHERN ROCKIES. TROUGHING SLOWLY MOVES EAST 12Z WED AND
OUT INTO THE PLAINS 12Z THU AND INTO THE UPPER GREAT LAKES 12Z FRI.
ACTIVE AND COLD WEATHER PATTERN LOOKS TO CONTINUE WITH TEMPERATURES
REMAINING WELL BELOW NORMAL AND WETTER THAN NORMAL CONDITIONS WILL
ALSO CONTINUE THIS FORECAST PERIOD. TUE AND TUE NIGHT LOOK DRY FOR
NOW BEFORE NEXT STRONG SYSTEM ARRIVES FOR WED INTO FRI. THIS NEXT
SYSTEM LOOKS LIKE A MESS FOR PCPN TYPE WITH RAIN/SNOW MIX WITH
MOSTLY SNOW FALLING AS COLDER AIR COMES IN BEHIND IT ESPECIALLY FOR
FRI WITH THE ECMWF SHOWING 850 MB TEMPERATURES FALLING TO -12C TO
-14C. CONTINUED HIGH CHANCE POPS TO LIKELYS FOR THIS SYSTEM LOOK
GOOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 147 PM EDT SAT APR 13 2013
LIGHT TO SOMETIMES MODERATE SNOW SHOWERS AFFECTING MAINLY IWD AND
SAW WILL DIMINISH THROUGHOUT THE AFTERNOON AS A TROUGH PASSES
THROUGH AND MOVE SOUTH OF THE AREA. EXPECT TEMPORARY VIS
RESTRICTIONS IN THE LIFR RANGE TO IMPROVE TO VFR VIS AT ALL SITES BY
LATER AFTERNOON. CLOUDS WILL START TO THIN OUT BY THIS
EVENING...THOUGH UPSLOPE FLOW AROUND CMX MAY KEEP A FEW HIGH-END
MVFR CLOUDS AROUND OVERNIGHT.
AN APPROACHING SYSTEM WILL BEGIN TO SPREAD MID-LEVEL CLOUDS ACROSS
UPPER MI LATE SUNDAY MORNING INTO THE AFTERNOON. IWD CAN EXPECT TO
SEE A MIX OF HEAVY SLEET...SNOW AND RAIN BY 21Z SUNDAY. CMX AND SAW
SHOULD SEE THE SAME BY 00Z MONDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 AM EDT SAT APR 13 2013
BROAD LOW PRESSURE JUST EAST OF THE AREA WILL MOVE OUT TODAY. STILL
SOME GUSTY N-NW WINDS ACROSS THE WEST LAKE THIS MORNING...BUT THE
EXPECTATION IS THAT THESE WILL DIMINISH LATER THIS AFTERNOON INTO
THIS EVENING AS THE RIDGE OVER THE UPPER MISSISSIPPI VALLEY MOVES
ACROSS THE LAKE. AS LOW PRESSURE OVER THE PLAINS DEVELOPS TODAY AND
MOVES NORTH...EXPECT E-NE WINDS TO INCREASE SUNDAY AFTERNOON AND
NIGHT. COULD NOT RULE OUT NE GALES SUNDAY EVENING ACROSS THE
WEST...THEN SE GALES ACROSS THE EAST HALF LATE SUNDAY NIGHT INTO
EARLY MONDAY MORNING...BUT THEY WOULD LIKELY BE MARGINAL AND SHORT
LIVED. WINDS TURN SW BEHIND AN OCCLUDED FRONT ON MONDAY...THEN
GRADUALLY TURN W AND NW ON TUE AS HIGH PRESSURE BUILDS BACK IN. NE
WINDS RETURN WED AND PERHAPS ANOTHER STORM SYSTEM FOR LATE IN THE
WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...07
AVIATION...TK
MARINE...MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
738 AM EDT SAT APR 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT SAT APR 13 2013
LAKE ENHANCEMENT HAVING A TOUGH TIME STARTING EARLY THIS
MORNING...EXCEPT FOR A BAND JUST WEST OF IWD. SEEMS LIKE THE MAIN
PROBLEM WITH ORGANIZATION IS LACK OF ANY SIGNIFICANT LOW LEVEL
CONVERGENCE DUE THE VERY WEAK WIND FIELDS OVER THE LAND. AGAIN...THE
EXCEPTION TO THIS IS OVER THE WEST WHERE CYCLONIC NNE FLOW IS QUITE
FAVORABLE FOR THE IWD AREA. LOCAL HI RES NWP AND ALONG WITH THE RAP
AND HRRR SUGGEST THAT AS THE LES WILL BECOME A LITTLE MORE ORGANIZED
BETWEEN 09Z AND 12Z AS THE SFC TROUGH OVER THE LAKE MOVES SOUTH AND
THE INVERSION DEEPENS TO NEARLY 8000FT AS WEAK Q-VECTOR CONVERGENCE
ASSOCIATED WITH THE UPPER TROUGH AXIS MOVES ACROSS THE AREA.
STILL...DESPITE THE EXPECTED INCREASED COVERAGE OF SNOW THIS
MORNING...THE FACT REMAINS THAT THERE IS NOT MUCH SNOW ONGOING RIGHT
NOW OTHER THAN FAR WESTERN GOGEBIC COUNTY...AND ANY ADDITIONAL
ACCUMULATION IN THE KEWEENAW AND IN THE NORTH CENTRAL AREAS WILL
ONLY AMOUNT TO AN INCH OR TWO. AS SUCH...HAVE OPTED TO DROP THE
ADVISORY FOR THOSE AREAS BUT KEEP IT FOR THE GOGEBIC AND ONTONAGON
THROUGH 15Z. SINCE IT IS NOT REALLY SNOWING IN THE CURRENT ADVISORY
AREA EXCEPT ACROSS THE FAR WEST...IT JUST DOES NOT SEEM PRUDENT TO
KEEP THE ADVISORY AT THIS TIME FOR MQT/BARAGA AND THE KEWEENAW FOR
ONLY AN ADDITIONAL INCH OR TWO OF ADDITIONAL SNOW. WILL STILL
FORECAST 2 TO LOCALLY 4 INCHES IN THE IRONWOOD/PORCUPINE MTNS AREA
FOR THIS MORNING AS THE SOUNDINGS LOOK QUITE FAVORABLE FOR A BRIEF
PERIOD OF MODERATE SNOWFALL WITH THE RISING INVERSION AND BETTER
DENDRITIC SNOW GROWTH WITH THE TOP OF THE INVERSION AROUND -18C.
AS THE LOW PULLS OUT...RIDGING SHOULD SLOWLY BUILD IN FROM THE WEST
THIS AFTERNOON INTO TONIGHT. THIS SHOULD ALLOW THE LES TO END FROM
WEST TO EAST DURING THE DAY AND INTO THIS EVENING. ANY LES THIS
EVENING WOULD BE FOCUSED IN AREAS EAST OF MUNISING DUE TO THE NW PBL
FLOW. HOWEVER...DO NOT EXPECT THIS LES TO LAST TOO LONG DUE TO THE
RIDGE BUILDING AND AND RAPIDLY DIMINISHING MOISTURE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 440 AM EDT SAT APR 13 2013
NAM SHOWS A 500 MB SHORTWAVE RIDGE OVER THE UPPER GREAT LAKES 12Z
SUN WITH A CLOSED LOW OVER THE NORTHERN ROCKIES. THIS CLOSED LOW
QUICKLY MOVES INTO THE NORTHERN PLAINS LATE SUN AND AFFECTS THE
UPPER GREAT LAKES SUN NIGHT BEFORE IT HEADS NORTHEAST AND SHEARS OUT
TO THE NORTH ON MON. NAM BRINGS IN SOME DEEPER MOISTURE SUN
AFTERNOON ALONG WITH 850-500 MB Q-VECTOR CONVERGENCE WHICH REMAINS
THROUGH SUN NIGHT BEFORE AREA GETS DRY SLOTTED ON MON. NAM SHOWS
SOME STRONG ISENTROPIC LIFT ON I280K-I295K SURFACES WITH DEEP
MOISTURE SUN EVENING WITH THE LIFT MOVING OUT BY 12Z MON. GFS AND
ECMWF SHOW ABOUT THE SAME THING AS WELL. LOOKS LIKE MON THAT MOST OF
THE CWA GETS DRY SLOTTED AND SHOULD HAVE BREEZY CONDITIONS ON
MONDAY. WITH DRY SLOT MOVING THROUGH...THINK THERE WILL BE SOME
SUNSHINE WITH SW WINDS ALLOWING SOME DOWNSLOPING TO OCCUR. FOR THIS
REASON AND A BIT MORE SUNSHINE...RAISED SOME HIGH TEMPERATURES A BIT
AND COULD SEE A FEW 50S FOR HIGHS ON MONDAY.
LOOKED AT A FEW THINGS AND AGREE WITH PREVIOUS SHIFTS THINKING OF
HAVING SOME SLEET...RAIN AND SNOW MENTIONED FOR PCPN TYPE FOR SUN
AFTERNOON AND EVENING BEFORE WARMING TAKES PLACE TO SWITCH ALL THE
PCPN OVER TO ALL RAIN LATE SUN NIGHT INTO MONDAY. COULD SEE
0.50-0.90 OF QPF FROM THIS EVENT WHICH WILL EQUATE OUT TO LESS THAN
TWO INCHES OF TOTAL SNOW AS THINGS ARE WARMING. WITH PCPN HOLDING
OFF UNTIL SUNDAY AFTERNOON...THINGS WILL BE WARM ENOUGH TO NOT HAVE
THE PCPN BE ALL SNOW OR SLEET. KEPT CATEGORICAL POPS IN FOR SUNDAY
NIGHT AND THEN HAVE DRY SLOT MOVING INTO THE WEST AND CENTRAL AREAS
FOR MON.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW IN JAMES
BAY 12Z TUE WITH TROUGHING EXTENDING FROM THAT BACK TO THE NORTHERN
PLAINS AND SOUTHERN ROCKIES. TROUGHING SLOWLY MOVES EAST 12Z WED AND
OUT INTO THE PLAINS 12Z THU AND INTO THE UPPER GREAT LAKES 12Z FRI.
ACTIVE AND COLD WEATHER PATTERN LOOKS TO CONTINUE WITH TEMPERATURES
REMAINING WELL BELOW NORMAL AND WETTER THAN NORMAL CONDITIONS WILL
ALSO CONTINUE THIS FORECAST PERIOD. TUE AND TUE NIGHT LOOK DRY FOR
NOW BEFORE NEXT STRONG SYSTEM ARRIVES FOR WED INTO FRI. THIS NEXT
SYSTEM LOOKS LIKE A MESS FOR PCPN TYPE WITH RAIN/SNOW MIX WITH
MOSTLY SNOW FALLING AS COLDER AIR COMES IN BEHIND IT ESPECIALLY FOR
FRI WITH THE ECMWF SHOWING 850 MB TEMPERATURES FALLING TO -12C TO
-14C. CONTINUED HIGH CHANCE POPS TO LIKELYS FOR THIS SYSTEM LOOK
GOOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 737 AM EDT SAT APR 13 2013
LIGHT SNOW WILL CONTINUE AT ALL OF THE TERMINALS THIS MORNING AS THE
UPPER LOW MOVES ACROSS THE AREA. IWD WILL BE THE MOST LIKELY TO SEE
IFR OR LIFR CONDITIONS THIS MORNING DUE THE LAKE ENHANCED
SNOW...ALTHOUGH ALL SITES HAVE THE POTENTIAL TO SEE IFR CONDITIONS
THIS MORNING BEFORE THE UPPER DISTURBANCE MOVES EAST. THE MOISTURE
AND REMAINING LIFT EXITS THE AREA BY THIS EVENING...WITH IWD SEEING
VFR CONDITIONS BY LATE THIS AFTERNOON. ONSHORE FLOW WILL KEEP CMX
AND SAW IN MVFR CONDITIONS UNTIL LATE TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 AM EDT SAT APR 13 2013
BROAD LOW PRESSURE JUST EAST OF THE AREA WILL MOVE OUT TODAY. STILL
SOME GUSTY N-NW WINDS ACROSS THE WEST LAKE THIS MORNING...BUT THE
EXPECTATION IS THAT THESE WILL DIMINISH LATER THIS AFTERNOON INTO
THIS EVENING AS THE RIDGE OVER THE UPPER MISSISSIPPI VALLEY MOVES
ACROSS THE LAKE. AS LOW PRESSURE OVER THE PLAINS DEVELOPS TODAY AND
MOVES NORTH...EXPECT E-NE WINDS TO INCREASE SUNDAY AFTERNOON AND
NIGHT. COULD NOT RULE OUT NE GALES SUNDAY EVENING ACROSS THE
WEST...THEN SE GALES ACROSS THE EAST HALF LATE SUNDAY NIGHT INTO
EARLY MONDAY MORNING...BUT THEY WOULD LIKELY BE MARGINAL AND SHORT
LIVED. WINDS TURN SW BEHIND AN OCCLUDED FRONT ON MONDAY...THEN
GRADUALLY TURN W AND NW ON TUE AS HIGH PRESSURE BUILDS BACK IN. NE
WINDS RETURN WED AND PERHAPS ANOTHER STORM SYSTEM FOR LATE IN THE
WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM EDT /10 AM CDT/ THIS MORNING
FOR MIZ002-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...07
AVIATION...MRD
MARINE...MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
440 AM EDT SAT APR 13 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT SAT APR 13 2013
LAKE ENHANCEMENT HAVING A TOUGH TIME STARTING EARLY THIS
MORNING...EXCEPT FOR A BAND JUST WEST OF IWD. SEEMS LIKE THE MAIN
PROBLEM WITH ORGANIZATION IS LACK OF ANY SIGNIFICANT LOW LEVEL
CONVERGENCE DUE THE VERY WEAK WIND FIELDS OVER THE LAND. AGAIN...THE
EXCEPTION TO THIS IS OVER THE WEST WHERE CYCLONIC NNE FLOW IS QUITE
FAVORABLE FOR THE IWD AREA. LOCAL HI RES NWP AND ALONG WITH THE RAP
AND HRRR SUGGEST THAT AS THE LES WILL BECOME A LITTLE MORE ORGANIZED
BETWEEN 09Z AND 12Z AS THE SFC TROUGH OVER THE LAKE MOVES SOUTH AND
THE INVERSION DEEPENS TO NEARLY 8000FT AS WEAK Q-VECTOR CONVERGENCE
ASSOCIATED WITH THE UPPER TROUGH AXIS MOVES ACROSS THE AREA.
STILL...DESPITE THE EXPECTED INCREASED COVERAGE OF SNOW THIS
MORNING...THE FACT REMAINS THAT THERE IS NOT MUCH SNOW ONGOING RIGHT
NOW OTHER THAN FAR WESTERN GOGEBIC COUNTY...AND ANY ADDITIONAL
ACCUMULATION IN THE KEWEENAW AND IN THE NORTH CENTRAL AREAS WILL
ONLY AMOUNT TO AN INCH OR TWO. AS SUCH...HAVE OPTED TO DROP THE
ADVISORY FOR THOSE AREAS BUT KEEP IT FOR THE GOGEBIC AND ONTONAGON
THROUGH 15Z. SINCE IT IS NOT REALLY SNOWING IN THE CURRENT ADVISORY
AREA EXCEPT ACROSS THE FAR WEST...IT JUST DOES NOT SEEM PRUDENT TO
KEEP THE ADVISORY AT THIS TIME FOR MQT/BARAGA AND THE KEWEENAW FOR
ONLY AN ADDITIONAL INCH OR TWO OF ADDITIONAL SNOW. WILL STILL
FORECAST 2 TO LOCALLY 4 INCHES IN THE IRONWOOD/PORCUPINE MTNS AREA
FOR THIS MORNING AS THE SOUNDINGS LOOK QUITE FAVORABLE FOR A BRIEF
PERIOD OF MODERATE SNOWFALL WITH THE RISING INVERSION AND BETTER
DENDRITIC SNOW GROWTH WITH THE TOP OF THE INVERSION AROUND -18C.
AS THE LOW PULLS OUT...RIDGING SHOULD SLOWLY BUILD IN FROM THE WEST
THIS AFTERNOON INTO TONIGHT. THIS SHOULD ALLOW THE LES TO END FROM
WEST TO EAST DURING THE DAY AND INTO THIS EVENING. ANY LES THIS
EVENING WOULD BE FOCUSED IN AREAS EAST OF MUNISING DUE TO THE NW PBL
FLOW. HOWEVER...DO NOT EXPECT THIS LES TO LAST TOO LONG DUE TO THE
RIDGE BUILDING AND AND RAPIDLY DIMINISHING MOISTURE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 440 AM EDT SAT APR 13 2013
NAM SHOWS A 500 MB SHORTWAVE RIDGE OVER THE UPPER GREAT LAKES 12Z
SUN WITH A CLOSED LOW OVER THE NORTHERN ROCKIES. THIS CLOSED LOW
QUICKLY MOVES INTO THE NORTHERN PLAINS LATE SUN AND AFFECTS THE
UPPER GREAT LAKES SUN NIGHT BEFORE IT HEADS NORTHEAST AND SHEARS OUT
TO THE NORTH ON MON. NAM BRINGS IN SOME DEEPER MOISTURE SUN
AFTERNOON ALONG WITH 850-500 MB Q-VECTOR CONVERGENCE WHICH REMAINS
THROUGH SUN NIGHT BEFORE AREA GETS DRY SLOTTED ON MON. NAM SHOWS
SOME STRONG ISENTROPIC LIFT ON I280K-I295K SURFACES WITH DEEP
MOISTURE SUN EVENING WITH THE LIFT MOVING OUT BY 12Z MON. GFS AND
ECMWF SHOW ABOUT THE SAME THING AS WELL. LOOKS LIKE MON THAT MOST OF
THE CWA GETS DRY SLOTTED AND SHOULD HAVE BREEZY CONDITIONS ON
MONDAY. WITH DRY SLOT MOVING THROUGH...THINK THERE WILL BE SOME
SUNSHINE WITH SW WINDS ALLOWING SOME DOWNSLOPING TO OCCUR. FOR THIS
REASON AND A BIT MORE SUNSHINE...RAISED SOME HIGH TEMPERATURES A BIT
AND COULD SEE A FEW 50S FOR HIGHS ON MONDAY.
LOOKED AT A FEW THINGS AND AGREE WITH PREVIOUS SHIFTS THINKING OF
HAVING SOME SLEET...RAIN AND SNOW MENTIONED FOR PCPN TYPE FOR SUN
AFTERNOON AND EVENING BEFORE WARMING TAKES PLACE TO SWITCH ALL THE
PCPN OVER TO ALL RAIN LATE SUN NIGHT INTO MONDAY. COULD SEE
0.50-0.90 OF QPF FROM THIS EVENT WHICH WILL EQUATE OUT TO LESS THAN
TWO INCHES OF TOTAL SNOW AS THINGS ARE WARMING. WITH PCPN HOLDING
OFF UNTIL SUNDAY AFTERNOON...THINGS WILL BE WARM ENOUGH TO NOT HAVE
THE PCPN BE ALL SNOW OR SLEET. KEPT CATEGORICAL POPS IN FOR SUNDAY
NIGHT AND THEN HAVE DRY SLOT MOVING INTO THE WEST AND CENTRAL AREAS
FOR MON.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW IN JAMES
BAY 12Z TUE WITH TROUGHING EXTENDING FROM THAT BACK TO THE NORTHERN
PLAINS AND SOUTHERN ROCKIES. TROUGHING SLOWLY MOVES EAST 12Z WED AND
OUT INTO THE PLAINS 12Z THU AND INTO THE UPPER GREAT LAKES 12Z FRI.
ACTIVE AND COLD WEATHER PATTERN LOOKS TO CONTINUE WITH TEMPERATURES
REMAINING WELL BELOW NORMAL AND WETTER THAN NORMAL CONDITIONS WILL
ALSO CONTINUE THIS FORECAST PERIOD. TUE AND TUE NIGHT LOOK DRY FOR
NOW BEFORE NEXT STRONG SYSTEM ARRIVES FOR WED INTO FRI. THIS NEXT
SYSTEM LOOKS LIKE A MESS FOR PCPN TYPE WITH RAIN/SNOW MIX WITH
MOSTLY SNOW FALLING AS COLDER AIR COMES IN BEHIND IT ESPECIALLY FOR
FRI WITH THE ECMWF SHOWING 850 MB TEMPERATURES FALLING TO -12C TO
-14C. CONTINUED HIGH CHANCE POPS TO LIKELYS FOR THIS SYSTEM LOOK
GOOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 158 AM EDT SAT APR 13 2013
SOME CLEARING AND LIGHTENING OF WINDS OVER THE PAST FEW HOURS HAS
LED TO SOME GROUND FOG AND VLIFR CONDITIONS AT SAW (AND ALSO ESC). AS
THE SURFACE TROUGH MOVES THROUGH IN THE NEXT FEW HRS...EXPECT THIS TO
SUBSIDE.
WITH MID/UPPER LEVEL LOW DRIFTING ACROSS THE AREA...SCT/NMRS -SHSN
WILL CONTINUE INTO THE MORNING HRS. AT KIWD...FAVORABLE UPSLOPE
NORTHERLY WINDS OFF THE LAKE SHOULD RESULT IN PREVAILING IFR
CONDITIONS. WOULDN`T BE SURPRISED TO SEE BRIEF LIFR AT TIMES AS WELL
AS MVFR. AT KCMX...EXPECT CONDITIONS VARYING BTWN MVFR AND IFR. IFR
MAY BE MORE PERSISTENT LATER IN THE NIGHT INTO THE MORNING AS SFC
TROF DRIFTS ACROSS THE AREA. AT KSAW...MVFR CONDITIONS SHOULD
PREVAIL FOR MUCH OF THE NIGHT. AS SFC TROF DROPS ACROSS THE AREA
LATE...CONDITIONS SHOULD FALL TO IFR. AT ALL SITES...EXPECT
IMPROVEMENT TO MVFR LATE THIS MORNING...AND -SHSN SHOULD END BY LATE
AFTN. MVFR CIGS MAY CLEAR OUT OF KIWD THIS EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 440 AM EDT SAT APR 13 2013
BROAD LOW PRESSURE JUST EAST OF THE AREA WILL MOVE OUT TODAY. STILL
SOME GUSTY N-NW WINDS ACROSS THE WEST LAKE THIS MORNING...BUT THE
EXPECTATION IS THAT THESE WILL DIMINISH LATER THIS AFTERNOON INTO
THIS EVENING AS THE RIDGE OVER THE UPPER MISSISSIPPI VALLEY MOVES
ACROSS THE LAKE. AS LOW PRESSURE OVER THE PLAINS DEVELOPS TODAY AND
MOVES NORTH...EXPECT E-NE WINDS TO INCREASE SUNDAY AFTERNOON AND
NIGHT. COULD NOT RULE OUT NE GALES SUNDAY EVENING ACROSS THE
WEST...THEN SE GALES ACROSS THE EAST HALF LATE SUNDAY NIGHT INTO
EARLY MONDAY MORNING...BUT THEY WOULD LIKELY BE MARGINAL AND SHORT
LIVED. WINDS TURN SW BEHIND AN OCCLUDED FRONT ON MONDAY...THEN
GRADUALLY TURN W AND NW ON TUE AS HIGH PRESSURE BUILDS BACK IN. NE
WINDS RETURN WED AND PERHAPS ANOTHER STORM SYSTEM FOR LATE IN THE
WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM EDT /10 AM CDT/ THIS MORNING
FOR MIZ002-009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...MRD
LONG TERM...07
AVIATION...MRD/ROLFSON
MARINE...MRD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
201 AM EDT SAT APR 13 2013
.UPDATE...
ISSUED AT 1034 PM EDT FRI APR 12 2013
NO CHANGES WERE MADE TO WINTER WX ADVY OVER THE W AND PORTION OF THE
NCNTRL EVEN THOUGH SNOW OVERALL THIS EVENING DOES NOT SUPPORT
MAINTAINING HEADLINES. AS WINDS BACK AROUND MORE NORTHERLY DURING
THE NIGHT AND WE HEAD INTO THE MORE FAVORABLE PART OF THE DIURNAL
CYCLE FOR LAKE EFFECT PROCESSES...THERE SHOULD BE SOME INCREASE IN
LAKE ENHANCED SNOW. IT ALSO APPEARS THAT INSTEAD OF GRADUALLY
BACKING WINDS...THE BACKING WINDS MAY OCCUR MORE AS A SFC TROF
PASSAGE AS HIGHER RES MODEL GUIDANCE INDICATES. THIS WOULD IMPROVE
CONVERGENCE AND OVERALL SNOW COVERAGE/INTENSITY LATE TONIGHT THRU
MID MORNING SAT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 445 PM EDT FRI APR 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NRN
WI WITH SHORTWAVE SPOKES INTO SRN UPPER MI AND WRN LAKE SUPERIOR.
WIDESPREAD LIGHT SNOW (VSBY IN THE 1-4SM RANGE) STILL PREVAILED
ACROSS MUCH OF UPPER MI WITH THE FAVORABLE UPPER LEVEL DIV AND
700-300 MB QVECTOR CONV TO THE NORTH OF THE LOW. AT THE SFC...LOW
PRES WAS LOCATED OVER NW LOWER MI NEAR TVC WITH A TROUGH EXTENDING
TO THE EAST TO LAKE ONTARIO. WITH THE SFC-850 MB TROUGH EDGING
CLOSER TO THE AREA...THE ENE LOW LEVEL FLOW HAD DIMINISHED. EVEN
WITH 850 MB TEMPS DOWN TO AROUND -11C...RADAR SHOWED ONLY MINIMAL IF
ANY LAKE ENHANCEMENT INTO N CNTRL UPPER MI.
EXPECT LIGHT SNOW ASSOCIATED WITH THE MID LEVEL LOW TO PERSIST THIS
EVENING BUT WITH ACCUMULATIONS OF LESS THAN AN INCH. WITH THE LOW
LEVEL TROUGH AXIS SHIFTING TO NEAR E UPPER MI...LOW LEVEL CONV FOR
LAKE ENHANCED SNOW WILL BE LESS FAVORABLE THIS EVENING. HOWEVER...AS
THE TROUGH SHIFTS TO THE EAST AND WINDS BACK MORE NRLY AND STRENGTHEN
OVERNIGHT INTO SATURDAY MORNING...LAKE ENHANCED SNOW IS EXPECTED TO
BECOME HEAVIER OVER THE WEST AND THEN SHIFT INTO N CNTRL UPPER MI
LATE TONIGHT INTO SATURDAY MORNING. EVEN WITH ONLY MARGINAL 850 MB
TEMPS NEAR -12C AND LAKE INDUCED CAPES TO NEAR 300 J/KG...ABUNDANT
850-500 MB MOISTURE AND CYCLONIC LOW LEVEL FLOW WILL FAVOR AT LEAST
LIGHT TO MODERATE SNOW. SNOW/WATER RATIOS SHOULD ALSO BECOME MORE
FAVORABLE WITH SIGNIFICANT UPWARD MOTION IN THE 850-750 MB DGZ LAYER.
EVEN WITH THE SNOW TAPERING OFF FOR A TIME TONIGHT...THE ADVISORIES
OVER THE NW HALF WERE EXTENDED INTO SATURDAY WITH HIGHER SNOWFALL
RATES AGAIN DEVELOPING. ADDITIONAL AMOUNTS FROM 00Z-18Z SHOULD STILL
REMAIN IN THE 2 TO 6 INCH RANGE.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 445 PM EDT FRI APR 12 2013
THE LONG RANGE LOOKS TO FEATURE AN WX ACTIVE PATTERN WITH BLO NORMAL
TEMPS OVERALL AS MEAN UPR TROF OVER CENTRAL NAMERICA LINGERS. MAIN
FOCUS WL BE ON NEXT LO PRES DISTURBANCE PROGGED TO IMPACT THE CWA
LATE SUN THRU SUN NGT.
SAT NGT...SHRTWV RDG AXIS BTWN DEPARTING/WEAKENING CLOSED LO OVER SE
CANADA AND NEXT SHRTWV/SFC LO MOVING INTO THE NRN PLAINS IS FCST TO
BLD INTO THE GRT LKS. WITH ARRIVAL OF SFC HI PRES RDG/DRYING ALF
UNDER THE RISING HGTS...LINGERING -SHSN UNDER MORE PERSISTENT CYC NW
FLOW/DEEPER MSTR/H85 TEMPS AS LO AS -10C IN THE EVNG OVER THE
NCENTRAL AND E WL END AND GIVE WAY TO AT LEAST PARTIAL CLRG.
SUN/SUN NGT...EXPECT A DRY START TO THE DAY ON SUN WITH SFC HI PRES
RDG SLOWLY DEPARTING TO THE E. BUT ANY MRNG SUNSHINE WL QUICKLY FADE
BEHIND INCRSG CLDS AS VIGOROUS ISENTROPIC ASCENT/SW FLOW BTWN THE
DEPARTING HI AND NEXT SHRTWV/SFC LO MOVING THRU THE NRN PLAINS AND
TOWARD MN LATE ON SUN OVERSPREADS UPR MI. AS UPR DVGC/BAND OF H5-7
FGEN AHEAD OF ATTENDANT WARM FNT MOVES IN AFT 18Z...EXPECT PCPN TO
OVERSPREAD THE CWA BY 00Z MON. PTYPE WL BE A CONCERN AT THE ONSET OF
THE PCPN EVENT SUN AFTN/EVNG. NAM/GFS FCST SDNGS INDICATE SATURATED
TEMP PROFILE WL AT LEAST INITIALLY BE COMPLETELY SUB ZERO...BUT THEN
SHOW ELEVATED WARM LYR ABV SUB ZERO NEAR SFC LYR. IN FACT...THESE
FCST SDNGS ALSO SUG PCPN MAY BE AT LEAST MIXED WITH SOME ZR FOR A
TIME LATE IN THE AFTN/EVNG OVER AT LEAST THE HIER TERRAIN OF THE W
HALF. BUT THESE SDNGS ALSO APPEAR TO UNDERDO THE SFC WARMING IN THE
AFTN FOLLOWING AT LEAST SOME MRNG SUNSHINE. WITH SOME LINGERING LLVL
DRY AIR...EVAPORATIVE COOLING COULD MAINTAIN SUB 32 NEAR SFC WBLB
TEMPS. BUT THE FCST NEAR SFC SE FLOW IN THE ABSENCE OF HI PRES
CENTER OVER ONTARIO AS WELL AS ARRIVAL OF PCPN AT MAX HEATING TIME
THIS LATE IN THE SEASON WOULD ALSO TEND TO MINIMIZE THIS THREAT.
HIER MOS TEMPS SEEM MORE APPROPRIATE FOR THE TEMPS THAN RAW MODEL
GUIDANCE. FOR NOW...WL FCST A SN/SLEET MIX AT THE ONSET
TRANSITIONING TO RA SUN EVNG AS MUCH WARMER/MSTR LLVL AIR SURGES
INTO THE UPR LKS ON THE HEELS OF H85 SW WINDS FCST UP TO 50-60KTS BY
06Z MON. EXPECT LITTLE IF ANY FALL OF TEMPS SUN NGT. THE NW CWA WL
HAVE THE BEST CHC FOR SEEING A LONGER PERIOD OF WINTRY PCPN WITH H85
TEMPS REMAINING BLO 0C THERE FOR A LONGER TIME. NEGATIVELY TILTED
APPEARANCE OF SHRTWV/VERY DIFFLUENT SW FLOW ALF/MSTR SURGE WITH PWAT
FCST UP TO 1 INCH SUN EVNG...OR 200 PCT OF NORMAL...INDICATE QPF
NEARING 1 INCH IS ON TRACK. RUNOFF FM THIS RA IN THE PRESENCE OF
LINGERING SN PILES MAY CAUSE SOME PONDING OF WATER. CONSIDERED
ADDING A CHC OF ELEVATED TS UNDER THE MOST IMPRESSIVE
MOISTENING/AXIS OF H85 LLJ...BUT FCST SDNGS SHOW H85-5 LAPSE RATES
NOT QUITE MOIST ADIABATIC. ARRIVAL OF DRY SLOT SUN NGT WL DIMINISH
POPS SW-NE AFTER THE EVNG.
MON...DRY SLOT ON THE SRN FLANK OF SHRTWV/SFC LO TRACKING ENEWD THRU
SRN ONTARIO WL END ANY LINGERING PCPN OVER THE E AND SCNTRL
ASSOCIATED WITH DEPARTING WARM CONVEYOR BELT. THE GFS IS MOST
AGGRESSIVE AT SHOWING SOME DEEPER MSTR/PCPN ON THE SE FLANK OF THE
UPR LO IMPACTING THE WRN ZNS...BUT BULK OF GUIDANCE INDICATES DEEPER
MSTR/PCPN WL REMAIN IN MN CLOSER TO LINGERING LO PRES TROF ON SW
FLANK OF LO DEPARTING TO THE NE. EXPECT AT LEAST PARTIAL SUNSHINE...
WHICH SHOULD BOOST MAX TEMPS INTO THE 40S AT MOST PLACES WITH H85
TEMPS FCST JUST A COUPLE DEGREES BLO 0C.
EXTENDED...DRYING/LLVL ACYC FLOW UNDER SLOWLY RISING HGTS BTWN
DEPARTING LO AND DEEPENING TROF IN THE ROCKIES WL BRING DRY WX AND
SEASONABLE TEMPS FOR MON NGT THRU TUE NGT. AS LO PRES LIFTS NEWD OUT
OF THE WRN TROF AND TOWARD THE GRT LKS ON WED INTO THU...ANOTHER
SGNFT MIXED PCPN EVENT APPEARS LIKELY. IF THE WELL CLUSTERED 00Z
ECMWF...CNDN...AND UKMET VERIFY...THE PTYPE WOULD BE MAINLY SN OVER
THE W HALF OF THE CWA WITH WARNING SN TOTALS LIKELY. THE 00Z/06Z/12Z
GFS ON THE OTHER HAND SHOWS A MUCH WEAKER LO TRACKING FARTHER TO THE
S AND MUCH LESS PCPN IMPACTING MAINLY THE SE HALF OF UPR MI. ALL
THESE SCENARIOS ARE WITHIN THE SPREAD SHOWN BY THE 00Z GFS ENSEMBLE
MEMBERS. COLDER AIR WITH SHSN WL FOLLOW ON FRI AS THE 00Z ECMWF
SHOWS H85 TEMPS TUMBLING TO -15C UNDER CYC NW FLOW LEFT IN THE WAKE
OF DEPARTING LO PRES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 158 AM EDT SAT APR 13 2013
SOME CLEARING AND LIGHTENING OF WINDS OVER THE PAST FEW HOURS HAS
LED TO SOME GROUND FOG AND VLIFR CONDITIONS AT SAW (AND ALSO ESC). AS
THE SURFACE TROUGH MOVES THROUGH IN THE NEXT FEW HRS...EXPECT THIS TO
SUBSIDE.
WITH MID/UPPER LEVEL LOW DRIFTING ACROSS THE AREA...SCT/NMRS -SHSN
WILL CONTINUE INTO THE MORNING HRS. AT KIWD...FAVORABLE UPSLOPE
NORTHERLY WINDS OFF THE LAKE SHOULD RESULT IN PREVAILING IFR
CONDITIONS. WOULDN`T BE SURPRISED TO SEE BRIEF LIFR AT TIMES AS WELL
AS MVFR. AT KCMX...EXPECT CONDITIONS VARYING BTWN MVFR AND IFR. IFR
MAY BE MORE PERSISTENT LATER IN THE NIGHT INTO THE MORNING AS SFC
TROF DRIFTS ACROSS THE AREA. AT KSAW...MVFR CONDITIONS SHOULD
PREVAIL FOR MUCH OF THE NIGHT. AS SFC TROF DROPS ACROSS THE AREA
LATE...CONDITIONS SHOULD FALL TO IFR. AT ALL SITES...EXPECT
IMPROVEMENT TO MVFR LATE THIS MORNING...AND -SHSN SHOULD END BY LATE
AFTN. MVFR CIGS MAY CLEAR OUT OF KIWD THIS EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 445 PM EDT FRI APR 12 2013
AS LOW PRESSURE OVER LOWER MICHIGAN SLIDES TO THE EAST TONIGHT AND
SATURDAY...WINDS WILL DIMINISH. THIS OCCURS...WINDS WILL GRADUALLY
SHIFT TO THE NORTH-NORTHWEST THROUGH SATURDAY AS A LINGERING SURFACE
TROUGH ROTATES THROUGH LAKE SUPERIOR. ENE GALES LATE THIS AFTERNOON
WILL DIMINISH TO 20 TO 30 KT WINDS TONIGHT AND INTO THE 15 TO 25 KT
RANGE SATURDAY.
WINDS ON SAT NIGHT WILL TURN LIGHT WITH THE ARRIVAL OF A HI PRES
RIDGE. EXPECT INCREASING E WINDS UP TO 25 TO 30 KTS VEERING TO THE
SE ON SUN INTO SUN NIGHT AHEAD OF A LO PRES SYSTEM MOVING FROM THE
NORTHERN PLAINS TOWARD MN. NOT OUT OF THE QUESTION THERE COULD BE
SOME GALES DURING THIS EVENT. AS THIS LO PASSES THRU ONTARIO ON
MON/MON NIGHT AND THE PRES GRADIENT OVER LAKE SUP DIMINISHES...THE
WINDS WILL SUBSIDE WHILE VEERING TO THE S AND THEN W INTO TUE. EXPECT
THE WINDS TO SHIFT TO THE N BY WED AS HI PRES BUILDS IN CENTRAL
CANADA AND ANOTHER LO PRES SYSTEM MOVES NE THRU THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR MIZ004-
005.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING
FOR MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 11 AM EDT THIS MORNING FOR MIZ001-
003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...JLB
LONG TERM...KC
AVIATION...MRD/ROLFSON
MARINE...JLB/KC
AREA FORECAST DISCUSSION
NWS DULUTH MN
941 PM CDT SUN APR 14 2013
.UPDATE...DRY SLOT IS BEGINNING TO WORK ITS WAY INTO THE SW
PORTION OF THE FA PER SATELLITE IMAGERY. MOISTURE FROM THE GULF
CONTINUES TO ADVECT INTO MUCH OF THE FA WHICH HAS LED TO THE PCPN
IN NW WI CHANGING OVER TO RAIN. HOWEVER...SFC TEMPS ARE HOVERING
AROUND 32F SO WILL PERSIST IN MONITORING FOR ADDITIONAL FZRA. SFC
OBS INDICATE THE FZRA HAS ENDED IN NW WI FOR NOW. EXPECT THE DRY
SLOT TO REACH THE TWIN PORTS AROUND 530Z. THIS WILL BRING THE
GUSTY WINDS TO AN END AS SEEN IN OBS DOWNSTREAM WHERE DRY SLOT HAS
ALREADY PASSED. MADE SOME MINOR ADJUSTMENTS TO THE WIND AS A
RESULT. REST OF THE FORECAST IN THE BALLPARK INCLUDING HEADLINES.
&&
.PREV DISCUSSION... /ISSUED 730 PM CDT SUN APR 14 2013/
UPDATE...ADDED FZRA TO NW WI AS FZRA HAS BEEN REPORTED AT
HYR AND SHELL LAKE. BAND OF HIGHER REFLECTIVITIES CURRENTLY ON
RADAR HAS BEEN MOSTLY FZRA...BUT REPORTS ARE BEGINNING TO INDICATE
IT IS CHANGING OVER TO RAIN. HAVE EXTENDED THE WINTER WEATHER
ADVISORIES IN MUCH OF NORTHWEST WI THAT WERE DUE TO EXPIRE AT 00Z
TO 06Z. THIS IS TO ACCOUNT FOR THE FZRA AND THE CONTINUED WINTRY
MIX THIS EVENING. NO OTHER BIG CHANGES.
AVIATION...00Z TAFS.
A WINTRY MIXED BAG OF PCPN TYPES ARE FORECAST AS THE SFC LOW MOVES
INTO SOUTHERN MN. CIGS AND VSBYS WILL VARY WILDLY FROM MVFR TO IFR
TO LIFR AND BACK AGAIN. SNOW WILL BE THE PREDOMINATE PTYPE FROM
BRD TO HIB AND INL WITH SNOW/SLEET AT DLH AND SNOW/FZRA/SLEET/RAIN
AFFECTING HYR. THIS WILL PERSIST THROUGH THE FORECAST. GUSTY SFC
WINDS WILL PREVAIL THROUGH THE FORECAST AS WELL.
PREV DISCUSSION... /ISSUED 308 PM CDT SUN APR 14 2013/
SHORT TERM.../NOW - MONDAY/
THE FOCUS REMAINS THE WINTRY STORM SYSTEM THAT IS BEGINNING TO
MOVE INTO THE SOUTHERN FORECAST AREA. OVERALL...THIS SYSTEM HAS
BEEN DIFFICULT TO FORECAST FOR DUE TO DELAYS IN WHICH THE PCPN
FORMS AND MOVES INTO THE FORECAST AREA...CONSIDERABLE MODEL
DIFFERENCES IN SNOWFALL AMOUNTS...AND PCPN TYPE ISSUES FOR
NW WISCONSIN AND EAST CENTRAL MINNESOTA. THROUGH THE COURSE OF
THIS SHIFT...I HAVE ATTEMPTED TO DELAY THE ONSET OF THE PCPN AND
COMMUNICATE THE DELAY VIA THE GRAPHIC WEATHER STORY AND ON
FACEBOOK. THE MODELS SUGGEST THAT THE PCPN WILL INCREASE IN ITS
NORTHWARD SPEED LATER THIS AFTERNOON...SO I THINK WE MAY HAVE
FINALLY GOTTEN CLOSER TO BETTER DETERMINING TIMING. I EXTENDED
SOME ADVISORIES INTO EARLY THIS EVENING BASED ON THE PCPN DELAY
AND TO ALLOW THE EVENING SHIFT FORECASTER TIME TO SEE HOW THINGS
PAN OUT. I ALSO NOW THINK SOME AREAS OF NORTHERN MINNESOTA COULD
GET ANOTHER INCH OR TWO OF MORE SNOW THAN PREVIOUSLY
THOUGHT...SUCH AS ALONG THE NORTH SHORE.
THROUGH TONIGHT...A POTENT MID/UPPER LEVEL LOW IN THE NORTHERN
HIGH PLAINS AND ITS ASSOCIATED SURFACE LOW IN THE CENTRAL PLAINS
(EASTERN NEBRASKA AND WESTERN IOWA) WILL LIFT INTO MINNESOTA
TONIGHT. THE PCPN EXPECTED WITH THIS SYSTEM IS MOVING NORTHWARD
FROM EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN AND ALREADY
BEGINNING TO MOVE INTO NORTHEAST MINNESOTA AND NORTHWEST
WISCONSIN. THE PCPN IS EXPECTED TO SPREAD ACROSS THE REST OF THE
NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN THROUGH THE REST OF
THE AFTERNOON AND INTO THIS EVENING. THE MODELS SUGGEST THE
INITIAL BAND OF PCPN WILL COME DOWN AS SNOW AND MAY COME DOWN
QUITE FAST...WITH LIKELY SNOW RATES OF UP TO 1 TO 2 INCHES PER
HOUR IF NOT MORE. RECENT HRRR MODEL RUNS HAVE SHOWN SOME PERIODS
LATER THIS AFTERNOON OF 2 TO 3 INCHES PER HOUR. THERE IS STRONG
FRONTOGENESIS WITH THIS INITIAL BAND...SO IT IS CERTAINLY
POSSIBLE. CONSIDERING THE RELATIVELY WARM TEMPERATURES ACROSS THE
FORECAST AREA...MID 30S TO LOW 40S...THE PCPN MAY BRIEFLY BEGIN AS
A LIGHT RAIN BEFORE SWITCHING OVER TO SNOW ONCE THE RATES INCREASE
AND THE COLUMN COOLS. THERE WILL ALSO LIKELY BE A TRANSITION TO
SLEET AND RAIN ACROSS MUCH OF NORTHWEST WISCONSIN LATE THIS
AFTERNOON AND THIS EVENING. MUCH OF NORTHEAST MINNESOTA SHOULD GET
ABOUT 4 TO 9 INCHES OF SNOW...WITH THE GREATEST TOTALS ACROSS FAR
NORTHERN MINNESOTA. SOME AREAS MAY GET UP TO 10 INCHES...SUCH AS
ALONG THE NORTH SHORE OF LAKE SUPERIOR. I EXPECT LESS AMOUNTS OF
SNOW ACROSS NORTHWEST WISCONSIN AND EAST CENTRAL MINNESOTA BECAUSE
OF THE SLEET AND RAIN. HOWEVER...I WOULD NOT BE SURPRISED IF SOME
AREAS SEE CONSIDERABLE ACCUMULATION OF SLEET...WHICH IS WHY I
INCLUDED THE ACCUMULATION IN THE SNOW TOTALS I PROVIDED IN THE
WINTER WEATHER ADVISORIES FOR NORTHWEST WISCONSIN. STRONG EAST
WINDS ARE DEVELOPING ACROSS THE FORECAST AREA THIS AFTERNOON...AND
THEY SHOULD CONTINUE TO STRENGTHEN INTO THIS EVENING. THE WINDS
WILL BE STRONGEST NEAR LAKE SUPERIOR...ESPECIALLY NEAR THE TWIN
PORTS. THE 15 TO 30 MPH WINDS WITH GUSTS UP TO 40 MPH NEAR LAKE
SUPERIOR COULD REALLY REDUCE VISIBILITY DURING THE HEAVIER SNOW
BANDS AND CAUSE BRIEF NEAR WHITE-OUT CONDITIONS.
MONDAY...THE SNOW WILL LIKELY CONTINUE ACROSS MOST OF THE FORECAST
AREA THROUGH AT LEAST THE EARLY AFTERNOON AS THE LOW LIFTS INTO
ONTARIO. UP TO ADDITIONAL 1 TO 3 INCHES OF SNOW COULD FALL ACROSS
THE NORTHERN FORECAST AREA DURING THE DAY. THE WINTER STORM
WARNING FOR THE NORTHERN FORECAST AREA RUNS THROUGH 15Z TOMORROW
MORNING...BUT WE MIGHT NEED TO EXTEND THE WARNING INTO SUNDAY
AFTERNOON IF THE SNOW AND REDUCED VISIBILITY ARE STILL LINGERING.
GUSTY SOUTH TO SOUTHWEST WINDS WILL DEVELOP IN THE WAKE OF THE
PASSING LOW PRESSURE SYSTEM. TEMPERATURES SHOULD BE IN THE UPPER
30S TO LOW 40S.
LONG TERM.../MONDAY NIGHT - SATURDAY/
THE UPPER LOW WILL BE OVER THE NORTHERN MINNESOTA/NORTHERN LAKE
SUPERIOR AREA 00Z TUESDAY THEN CONTINUE E/NE MONDAY NIGHT. A BAGGY
UPPER TROUGH...WITH AN EXTENSION TO THE SURFACE WILL REMAIN OVER
THE CWA INTO MONDAY NIGHT. WE KEPT A CHANCE FOR SNOW OVER MUCH OF
OUR NORTHEAST MINNESOTA ZONES MONDAY NIGHT...WITH THE BEST CHANCE
OVER THE BORDER REGION.
AN UPPER RIDGE WILL BUILD OVER THE REGION BRIEFLY TUESDAY...WITH
MOST AREAS DRY INTO TUESDAY NIGHT.
A DEEP TROUGH WILL THEN MOVE OVER THE ROCKIES TUESDAY
NIGHT...MOVING SLOWLY EAST THROUGH THE WEEK AFFECTING THE
NORTHLAND. ANOTHER SPRING STORM IS POISED TO AFFECT THE NORTHLAND
WEDNESDAY INTO AT LEAST THURSDAY...POSSIBLY LINGERING A BIT
LONGER. BOTH THE GFS AND ECMWF ARE IN GENERAL AGREEMENT WITH THE
TRACK OF THE SURFACE LOW...TAKING IT FROM THE TEXAS PANHANDLE AT
12Z WEDNESDAY TO LAKE MICHIGAN/SOUTHEAST WISCONSIN BY 12Z
THURSDAY...THEN IT CONTINUES NORTHEAST. AS IS THE CASE WITH THESE
SPRING STORMS...THE THERMAL PROFILES WILL BE CRITICAL TO PRECIP
TYPE. IT DOES APPEAR TEMPERATURES WILL BE WARM ENOUGH FOR A MIX
OVER AT LEAST NORTHWEST WISCONSIN. WE HAVE A RAIN/SNOW MIX OVER
NORTHWEST WISCONSIN WEDNESDAY NIGHT/THURSDAY...AND WILL LIKELY
NEED TO ADJUST THAT AS THIS SYSTEM NEARS. THE THREAT FOR MORE
ACCUMULATING SNOW IS INCREASING OVER NORTHEAST MINNESOTA INTO FAR
NORTHWEST WISCONSIN WEDNESDAY INTO THURSDAY. IT`S VERY DIFFICULT
TO TRY AND PLACE A NUMBER ON SNOW ACCUMULATION AT THIS POINT WITH
SO MUCH UNCERTAINTY REVOLVING THE PRECIP TYPE...BUT AT LEAST
SEVERAL INCHES OF SNOW WILL FALL OVER EASTERN MINNESOTA/FAR
NORTHWEST WISCONSIN FROM THIS SYSTEM. THE FORECAST MID-LATE WEEK
IS WORTH MONITORING CLOSELY AS THE PROBABILITY IT WILL HAVE A
SIGNIFICANT IMPACT ON THE NORTHLAND/S WEATHER IS INCREASING. MORE
DETAIL REGARDING PRECIP TYPE/AMOUNTS WILL BE ADDED AS WE PROGRESS
INTO THE EARLY PART OF THE WEEK.
AS THE UPPER TROUGH PASSES LATE IN THE WEEK...A SURFACE HIGH WILL
MOVE OVER THE AREA DRYING THINGS OUT FOR A TIME LATE IN THE
WEEK/EARLY WEEKEND. ANOTHER SHORTWAVE WILL BRING ANOTHER CHANCE
FOR MIXED PRECIP SATURDAY NIGHT/SUNDAY BUT THIS SYSTEM DOES NOT
LOOK TO BE PARTICULARLY STRONG.
TEMPERATURES THROUGH MOST OF THE PERIOD WILL REMAIN BELOW NORMAL.
AVIATION.../18Z TAFS/
AREA RADARS SHOWED PRECIPITATION WAS MOVING NORTH THROUGH
MINNESOTA/WISCONSIN...AND WAS BECOMING MORE WIDESPREAD. THE NAM
HAS A PRETTY GOOD HANDLE ON THIS...AS DO THE HIGH RES MODELS. WE
EXPECT THE PRECIPITATION TO BEGIN AS SNOW ALL AREAS...THEN IT MAY
BECOME A WINTRY MIX AT KHYR...AND POSSIBLY AT KBRD BRIEFLY. TIMING
IN THE TAFS MAY NEED TO BE ADJUSTED BY AN HOUR OR SO...AND WE`LL
DO THAT AS CONFIDENCE INCREASES FOR AN EXACT STARTING TIME.
VSBYS WILL DROP TO IFR OR LIFR WITHIN AN HOUR OF PRECIP
ONSET...AND AREAS AROUND LAKE SUPERIOR WILL SEE WINDY CONDITIONS
FURTHER REDUCING THE VSBY IN BLOWING SNOW. A DRY SLOT WILL WORK
NORTH LATER THIS EVENING/TONIGHT AND CAUSE THE PRECIP TO DIMINISH
OVER MOST OF THE TAFS. FORECAST SOUNDINGS SHOW TOP DOWN
DRYING...SO SOME SPOTTY DRIZZLE OR FREEZING DRIZZLE IS NOT OUT OF
THE QUESTION. WE DID NOT ADD THAT TO THE TAFS AT THIS TIME...AS
THAT IS MORE OF A SHORT TERM FORECAST ISSUE AND CAN BE ADDRESSED
WITH LATER UPDATES.
WINDS WILL SWITCH FROM EASTERLY TO SOUTHERLY LAT TONIGHT/MONDAY
MORNING...THEN BECOME SOUTHWEST.
&&
.POINT TEMPS/POPS...
DLH 29 38 30 38 / 100 70 20 10
INL 28 38 26 36 / 100 90 50 20
BRD 29 39 29 38 / 90 70 10 10
HYR 32 41 30 42 / 100 40 10 10
ASX 31 42 31 41 / 100 40 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT MONDAY FOR MNZ025-026-
033>035-037.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR MNZ036-038.
WINTER STORM WARNING UNTIL 10 AM CDT MONDAY FOR MNZ010>012-
018>021.
WI...WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ003-004-
006>009.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR WIZ001-002.
LS...GALE WARNING UNTIL 3 AM CDT MONDAY FOR LSZ121-140>148.
&&
$$
SHORT TERM...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
730 PM CDT SUN APR 14 2013
.UPDATE...ADDED FZRA TO NW WI AS FZRA HAS BEEN REPORTED AT
HYR AND SHELL LAKE. BAND OF HIGHER REFLECTIVITIES CURRENTLY ON
RADAR HAS BEEN MOSTLY FZRA...BUT REPORTS ARE BEGINNING TO INDICATE
IT IS CHANGING OVER TO RAIN. HAVE EXTENDED THE WINTER WEATHER
ADVISORIES IN MUCH OF NORTHWEST WI THAT WERE DUE TO EXPIRE AT 00Z
TO 06Z. THIS IS TO ACCOUNT FOR THE FZRA AND THE CONTINUED WINTRY
MIX THIS EVENING. NO OTHER BIG CHANGES.
.AVIATION...00Z TAFS.
A WINTRY MIXED BAG OF PCPN TYPES ARE FORECAST AS THE SFC LOW MOVES
INTO SOUTHERN MN. CIGS AND VSBYS WILL VARY WILDLY FROM MVFR TO IFR
TO LIFR AND BACK AGAIN. SNOW WILL BE THE PREDOMINATE PTYPE FROM
BRD TO HIB AND INL WITH SNOW/SLEET AT DLH AND SNOW/FZRA/SLEET/RAIN
AFFECTING HYR. THIS WILL PERSIST THROUGH THE FORECAST. GUSTY SFC
WINDS WILL PREVAIL THROUGH THE FORECAST AS WELL.
&&
.PREV DISCUSSION... /ISSUED 308 PM CDT SUN APR 14 2013/
SHORT TERM.../NOW - MONDAY/
THE FOCUS REMAINS THE WINTRY STORM SYSTEM THAT IS BEGINNING TO
MOVE INTO THE SOUTHERN FORECAST AREA. OVERALL...THIS SYSTEM HAS
BEEN DIFFICULT TO FORECAST FOR DUE TO DELAYS IN WHICH THE PCPN
FORMS AND MOVES INTO THE FORECAST AREA...CONSIDERABLE MODEL
DIFFERENCES IN SNOWFALL AMOUNTS...AND PCPN TYPE ISSUES FOR
NW WISCONSIN AND EAST CENTRAL MINNESOTA. THROUGH THE COURSE OF
THIS SHIFT...I HAVE ATTEMPTED TO DELAY THE ONSET OF THE PCPN AND
COMMUNICATE THE DELAY VIA THE GRAPHIC WEATHER STORY AND ON
FACEBOOK. THE MODELS SUGGEST THAT THE PCPN WILL INCREASE IN ITS
NORTHWARD SPEED LATER THIS AFTERNOON...SO I THINK WE MAY HAVE
FINALLY GOTTEN CLOSER TO BETTER DETERMINING TIMING. I EXTENDED
SOME ADVISORIES INTO EARLY THIS EVENING BASED ON THE PCPN DELAY
AND TO ALLOW THE EVENING SHIFT FORECASTER TIME TO SEE HOW THINGS
PAN OUT. I ALSO NOW THINK SOME AREAS OF NORTHERN MINNESOTA COULD
GET ANOTHER INCH OR TWO OF MORE SNOW THAN PREVIOUSLY
THOUGHT...SUCH AS ALONG THE NORTH SHORE.
THROUGH TONIGHT...A POTENT MID/UPPER LEVEL LOW IN THE NORTHERN
HIGH PLAINS AND ITS ASSOCIATED SURFACE LOW IN THE CENTRAL PLAINS
(EASTERN NEBRASKA AND WESTERN IOWA) WILL LIFT INTO MINNESOTA
TONIGHT. THE PCPN EXPECTED WITH THIS SYSTEM IS MOVING NORTHWARD
FROM EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN AND ALREADY
BEGINNING TO MOVE INTO NORTHEAST MINNESOTA AND NORTHWEST
WISCONSIN. THE PCPN IS EXPECTED TO SPREAD ACROSS THE REST OF THE
NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN THROUGH THE REST OF
THE AFTERNOON AND INTO THIS EVENING. THE MODELS SUGGEST THE
INITIAL BAND OF PCPN WILL COME DOWN AS SNOW AND MAY COME DOWN
QUITE FAST...WITH LIKELY SNOW RATES OF UP TO 1 TO 2 INCHES PER
HOUR IF NOT MORE. RECENT HRRR MODEL RUNS HAVE SHOWN SOME PERIODS
LATER THIS AFTERNOON OF 2 TO 3 INCHES PER HOUR. THERE IS STRONG
FRONTOGENESIS WITH THIS INITIAL BAND...SO IT IS CERTAINLY
POSSIBLE. CONSIDERING THE RELATIVELY WARM TEMPERATURES ACROSS THE
FORECAST AREA...MID 30S TO LOW 40S...THE PCPN MAY BRIEFLY BEGIN AS
A LIGHT RAIN BEFORE SWITCHING OVER TO SNOW ONCE THE RATES INCREASE
AND THE COLUMN COOLS. THERE WILL ALSO LIKELY BE A TRANSITION TO
SLEET AND RAIN ACROSS MUCH OF NORTHWEST WISCONSIN LATE THIS
AFTERNOON AND THIS EVENING. MUCH OF NORTHEAST MINNESOTA SHOULD GET
ABOUT 4 TO 9 INCHES OF SNOW...WITH THE GREATEST TOTALS ACROSS FAR
NORTHERN MINNESOTA. SOME AREAS MAY GET UP TO 10 INCHES...SUCH AS
ALONG THE NORTH SHORE OF LAKE SUPERIOR. I EXPECT LESS AMOUNTS OF
SNOW ACROSS NORTHWEST WISCONSIN AND EAST CENTRAL MINNESOTA BECAUSE
OF THE SLEET AND RAIN. HOWEVER...I WOULD NOT BE SURPRISED IF SOME
AREAS SEE CONSIDERABLE ACCUMULATION OF SLEET...WHICH IS WHY I
INCLUDED THE ACCUMULATION IN THE SNOW TOTALS I PROVIDED IN THE
WINTER WEATHER ADVISORIES FOR NORTHWEST WISCONSIN. STRONG EAST
WINDS ARE DEVELOPING ACROSS THE FORECAST AREA THIS AFTERNOON...AND
THEY SHOULD CONTINUE TO STRENGTHEN INTO THIS EVENING. THE WINDS
WILL BE STRONGEST NEAR LAKE SUPERIOR...ESPECIALLY NEAR THE TWIN
PORTS. THE 15 TO 30 MPH WINDS WITH GUSTS UP TO 40 MPH NEAR LAKE
SUPERIOR COULD REALLY REDUCE VISIBILITY DURING THE HEAVIER SNOW
BANDS AND CAUSE BRIEF NEAR WHITE-OUT CONDITIONS.
MONDAY...THE SNOW WILL LIKELY CONTINUE ACROSS MOST OF THE FORECAST
AREA THROUGH AT LEAST THE EARLY AFTERNOON AS THE LOW LIFTS INTO
ONTARIO. UP TO ADDITIONAL 1 TO 3 INCHES OF SNOW COULD FALL ACROSS
THE NORTHERN FORECAST AREA DURING THE DAY. THE WINTER STORM
WARNING FOR THE NORTHERN FORECAST AREA RUNS THROUGH 15Z TOMORROW
MORNING...BUT WE MIGHT NEED TO EXTEND THE WARNING INTO SUNDAY
AFTERNOON IF THE SNOW AND REDUCED VISIBILITY ARE STILL LINGERING.
GUSTY SOUTH TO SOUTHWEST WINDS WILL DEVELOP IN THE WAKE OF THE
PASSING LOW PRESSURE SYSTEM. TEMPERATURES SHOULD BE IN THE UPPER
30S TO LOW 40S.
LONG TERM.../MONDAY NIGHT - SATURDAY/
THE UPPER LOW WILL BE OVER THE NORTHERN MINNESOTA/NORTHERN LAKE
SUPERIOR AREA 00Z TUESDAY THEN CONTINUE E/NE MONDAY NIGHT. A BAGGY
UPPER TROUGH...WITH AN EXTENSION TO THE SURFACE WILL REMAIN OVER
THE CWA INTO MONDAY NIGHT. WE KEPT A CHANCE FOR SNOW OVER MUCH OF
OUR NORTHEAST MINNESOTA ZONES MONDAY NIGHT...WITH THE BEST CHANCE
OVER THE BORDER REGION.
AN UPPER RIDGE WILL BUILD OVER THE REGION BRIEFLY TUESDAY...WITH
MOST AREAS DRY INTO TUESDAY NIGHT.
A DEEP TROUGH WILL THEN MOVE OVER THE ROCKIES TUESDAY
NIGHT...MOVING SLOWLY EAST THROUGH THE WEEK AFFECTING THE
NORTHLAND. ANOTHER SPRING STORM IS POISED TO AFFECT THE NORTHLAND
WEDNESDAY INTO AT LEAST THURSDAY...POSSIBLY LINGERING A BIT
LONGER. BOTH THE GFS AND ECMWF ARE IN GENERAL AGREEMENT WITH THE
TRACK OF THE SURFACE LOW...TAKING IT FROM THE TEXAS PANHANDLE AT
12Z WEDNESDAY TO LAKE MICHIGAN/SOUTHEAST WISCONSIN BY 12Z
THURSDAY...THEN IT CONTINUES NORTHEAST. AS IS THE CASE WITH THESE
SPRING STORMS...THE THERMAL PROFILES WILL BE CRITICAL TO PRECIP
TYPE. IT DOES APPEAR TEMPERATURES WILL BE WARM ENOUGH FOR A MIX
OVER AT LEAST NORTHWEST WISCONSIN. WE HAVE A RAIN/SNOW MIX OVER
NORTHWEST WISCONSIN WEDNESDAY NIGHT/THURSDAY...AND WILL LIKELY
NEED TO ADJUST THAT AS THIS SYSTEM NEARS. THE THREAT FOR MORE
ACCUMULATING SNOW IS INCREASING OVER NORTHEAST MINNESOTA INTO FAR
NORTHWEST WISCONSIN WEDNESDAY INTO THURSDAY. IT`S VERY DIFFICULT
TO TRY AND PLACE A NUMBER ON SNOW ACCUMULATION AT THIS POINT WITH
SO MUCH UNCERTAINTY REVOLVING THE PRECIP TYPE...BUT AT LEAST
SEVERAL INCHES OF SNOW WILL FALL OVER EASTERN MINNESOTA/FAR
NORTHWEST WISCONSIN FROM THIS SYSTEM. THE FORECAST MID-LATE WEEK
IS WORTH MONITORING CLOSELY AS THE PROBABILITY IT WILL HAVE A
SIGNIFICANT IMPACT ON THE NORTHLAND/S WEATHER IS INCREASING. MORE
DETAIL REGARDING PRECIP TYPE/AMOUNTS WILL BE ADDED AS WE PROGRESS
INTO THE EARLY PART OF THE WEEK.
AS THE UPPER TROUGH PASSES LATE IN THE WEEK...A SURFACE HIGH WILL
MOVE OVER THE AREA DRYING THINGS OUT FOR A TIME LATE IN THE
WEEK/EARLY WEEKEND. ANOTHER SHORTWAVE WILL BRING ANOTHER CHANCE
FOR MIXED PRECIP SATURDAY NIGHT/SUNDAY BUT THIS SYSTEM DOES NOT
LOOK TO BE PARTICULARLY STRONG.
TEMPERATURES THROUGH MOST OF THE PERIOD WILL REMAIN BELOW NORMAL.
AVIATION.../18Z TAFS/
AREA RADARS SHOWED PRECIPITATION WAS MOVING NORTH THROUGH
MINNESOTA/WISCONSIN...AND WAS BECOMING MORE WIDESPREAD. THE NAM
HAS A PRETTY GOOD HANDLE ON THIS...AS DO THE HIGH RES MODELS. WE
EXPECT THE PRECIPITATION TO BEGIN AS SNOW ALL AREAS...THEN IT MAY
BECOME A WINTRY MIX AT KHYR...AND POSSIBLY AT KBRD BRIEFLY. TIMING
IN THE TAFS MAY NEED TO BE ADJUSTED BY AN HOUR OR SO...AND WE`LL
DO THAT AS CONFIDENCE INCREASES FOR AN EXACT STARTING TIME.
VSBYS WILL DROP TO IFR OR LIFR WITHIN AN HOUR OF PRECIP
ONSET...AND AREAS AROUND LAKE SUPERIOR WILL SEE WINDY CONDITIONS
FURTHER REDUCING THE VSBY IN BLOWING SNOW. A DRY SLOT WILL WORK
NORTH LATER THIS EVENING/TONIGHT AND CAUSE THE PRECIP TO DIMINISH
OVER MOST OF THE TAFS. FORECAST SOUNDINGS SHOW TOP DOWN
DRYING...SO SOME SPOTTY DRIZZLE OR FREEZING DRIZZLE IS NOT OUT OF
THE QUESTION. WE DID NOT ADD THAT TO THE TAFS AT THIS TIME...AS
THAT IS MORE OF A SHORT TERM FORECAST ISSUE AND CAN BE ADDRESSED
WITH LATER UPDATES.
WINDS WILL SWITCH FROM EASTERLY TO SOUTHERLY LAT TONIGHT/MONDAY
MORNING...THEN BECOME SOUTHWEST.
&&
.POINT TEMPS/POPS...
DLH 28 38 30 38 / 100 70 20 10
INL 28 38 26 36 / 100 90 50 20
BRD 29 39 29 38 / 90 70 10 10
HYR 32 41 30 42 / 100 40 10 10
ASX 31 42 31 41 / 100 40 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT MONDAY FOR MNZ025-026-
033>035-037.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR MNZ036-038.
WINTER STORM WARNING UNTIL 10 AM CDT MONDAY FOR MNZ010>012-
018>021.
WI...WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ003-004-
006>009.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR WIZ001-002.
LS...GALE WARNING UNTIL 3 AM CDT MONDAY FOR LSZ121-140>148.
&&
$$
SHORT TERM...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1241 PM CDT SAT APR 13 2013
.AVIATION...18Z TAFS
A MIX OF CEILINGS FROM 2500-3500FT COVERED THE NORTHLAND...DUE TO
A STRATOCUMULUS DECK THAT QUICKLY DEVELOPED THIS MORNING. WE
EXPECT CEILINGS CONTINUE TO SLOWLY RISE THIS AFTERNOON...BUT THERE
ALSO COULD BE A FEW SNOW SHOWERS THAT BRING MORE MVFR CONDITIONS
BRIEFLY. IT SHOULD BECOME MOSTLY VFR THIS EVENING...THEN AN
APPROACHING LOW PRESSURE SYSTEM WILL DROP CEILINGS AND EVENTUALLY
VSBYS AS PRECIPITATION MOVES NORTH. THE PRECIPITATION SHOULD START
AS MOSTLY SNOW...AND AFFECT KBRD FIRST...THEN KHYR/KDLH AND
EVENTUALLY KHIB/KINL. KHYR HAS THE BEST CHANCE AT SEEING A
MIXTURE.
WINDS WILL TURN OUT OF THE EAST LATER TONIGHT...AND INCREASE AND
BECOME GUSTY DURING THE DAY SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 1002 AM CDT SAT APR 13 2013/
UPDATE...
THE MAIN CHALLENGE FOR THIS UPDATE TO THE FORECAST IS THE
LINGERING SNOW IN NW WISCONSIN. OBSERVATIONS FROM
IRONWOOD AND ASHLAND...THE CURRENT RADAR...AND CALLS FROM
OBSERVERS SUGGEST THIS SNOW IS LINGERING LONGER THAN PREVIOUSLY
THOUGHT IT WOULD. THE SNOW IS REDUCING VISIBILITY QUITE A BIT AT
TIMES. THE LATEST NAM AND HRRR MODELS SHOW IT THE HEAVIER SNOW
BANDS LINGERING LONGER...SO I EXTENDED THE WINTER WEATHER ADVISORY
FOR IRON AND ASHLAND COUNTIES TILL NOON. I WOULD NOT BE SURPRISED
IF SOME AREAS GET AN ADDITIONAL 1 TO 2 INCHES NEAR AND ALONG THE
GOGEBIC RANGE.
OTHERWISE...THE REST OF THE FORECAST FOR TODAY IS RELATIVELY
QUIET. I LOWERED CLOUD COVER THIS MORNING IN SOME AREAS THAT HAVE
SOME PARTIAL CLEAR...BUT I THINK THE FORECAST AREA WILL MOSTLY
HAVE CLOUDY OR MOSTLY CLOUDY SKIES TODAY.
THE FOCUS WHEN I MAKE MY NEW FORECAST THIS AFTERNOON WILL OF
COURSE BE THE NEXT SPRINGTIME WINTER STORM THAT IS POISED TO
STRIKE THE NORTHLAND SUNDAY AND SUNDAY NIGHT. COMPARED TO WHAT I
SAW IN THE 12Z MODELS YESTERDAY...THE SNOWFALL ACROSS NE MINNESOTA
IN THE 00Z MODELS SNOWFALL SEEMS TO BE LOWER THAN YESTERDAY. IF
THE NEW 12Z MODELS REMAIN FAIRLY CONSISTENT AND AGREEABLE BETWEEN
EACH OTHER...THAN WE WILL PROBABLY ISSUE WINTER STORM WARNINGS AND
ADVISORIES FOR THIS NEXT ROUND OF SNOW.
PREV DISCUSSION... /ISSUED 711 AM CDT SAT APR 13 2013/
AVIATION.../12Z TAF ISSUANCE/
THE LARGE WINTER STORM THAT MOVED THROUGH OVER THE PAST FEW DAYS
WILL GRADUALLY PULL OUT OVER THE NEXT 24 HOURS. THE RESULT WILL BE
WIDELY VARYING CLOUD HEIGHTS AND VISIBILITIES AS THE LOW MOVES
EAST AND THE CLOUDS AND SNOW SHOWERS TRY TO BREAK UP. CONDITIONS
WILL VARY BETWEEN VFR AND MVFR AND LOCALLY IFR.
SHORT TERM...
CURRENT...VERTICALLY STACKED CIRCULATION OVER ERN LAKE SUPERIOR
IS MAINTAINING A MOIST CYCLONIC FLOW OVER CWA EARLY THIS MORNING.
ABUNDANCE OF CLOUDS WITH SOME WIND AND LIGHT PRECIP HAS KEPT
TEMPS ACROSS CWA FAIRLY UNIFORM. LOWEST READINGS ARE IN THE MN
ARROWHEAD WITH TEENS ...AND 20S ELSEWHERE.
TODAY...WIDESPREAD AREA OF LIGHT SNOW ACROSS MN ZONES WILL ADVECT
EASTWARD INTO WISC ZONES THROUGH REMAINDER OF MORNING. WILL LET WSW
EXPIRE IN BAYFIELD COUNTY AT 12Z AND EXTEND ASHLAND/IRON COUNTIES
TIL 15Z. ALTHOUGH CYCLONIC FLOW WILL PERSIST SFC/ALOFT TODAY...DEEP
LAYER RH IS EXPECTED TO GRADUALLY DIMINISH. LT SNOW/SNOW SHOWERS
WILL PERSIST THROUGH MID AFTN OVER MN ZONES..AND PERHAPS UNTIL LATE
AFN OVER WISC ZONES. MAX TEMPS REMAIN WELL BLO CLIMO WITH MID 30S
PREVAILING.
TONIGHT...PROGRESSIVE FLOW ALOFT WILL ALLOW MID LVL RIDGING TO PUSH
INTO CWA FROM THE SOUTHWEST OVERNIGHT. AN ELONGATED AREA OF LOW
PRESSURE AT THE SFC WILL STRETCH FROM CTRL SD TO ERN NEB BY 12Z
SUNDAY. CLOUDS WILL INCREASE OVER SWRN CWA WITH SNOW DEVELOPING
AROUND 09Z AS AN AREA OF WARM FRONTOGENESIS INCREASES.
TOMORROW...MDLS AGREE THAT A DUAL LOBE SFC PRESS PATTERN WILL
CONTINUE TO MOVE NORTHEAST. THE NRN LOW WILL MOVE TOWARDS THE ND/SD
BORDER BY 00Z WHILE THE SECONDARY LOW WILL MIGRATE TO SERN MN. AN
AREA OF STRONG 85H FRONTOGENESIS WILL BE RESPONSIBLE FOR AN AREA OF
MODERATE INTENSITY SNOWFALL MAKING ITS WAY ACROSS MOST OF MN ZONES
EXCEPT ERN ARROWHEAD. A GENERAL 3 TO 6 INCH SNOWFALL APPEARS
INCREASING LIKELY FROM THE BRAINERD LAKES REGION TO TWIN PORTS AND
POINTS NORTH AND WEST. A TRANSITION IN PTYPE SHOULD OCCUR IN THE SRN
THIRD OF THE CWA BY AFTN AS ICE PELLETS AND RAIN BEGIN TO DEVELOP.
WITH PROSPECT FOR ACCUMULATING SNOW TO CONTINUE BEYOND THIS PERIOD
WILL LET DAY SHIFT DECIDE IF AN ADVISORY OR WARNING WILL BE ISSUED
FOR SUNDAY/SUNDAY NIGHT EVENT.
PREV DISCUSSION... /ISSUED 332 AM CDT SAT APR 13 2013/
EXTENDED...SUNDAY NIGHT THROUGH SATURDAY...
THE STRONG LOW PRESSURE SYSTEM THAT WILL MOVE THROUGH LATE IN THE
WEEKEND WILL CONTINUE TO AFFECT THE NORTHLAND INTO SUNDAY NIGHT.
THERE WILL LIKELY STILL BE SOME ACCUMULATION INTO THE
NIGHT...ESPECIALLY ACROSS NE MN. A MIX IS EXPECTED FROM EC MN INTO
PORTIONS OF NW WI...WITH MAINLY RAIN ACROSS THE FAR SE. STRONG WINDS
WILL GRADUALLY SUBSIDE AS THE SURFACE LOW MOVES INTO NORTHERN
MN...BUT STRONG NW TO W WINDS WILL THEN DEVELOP ON THE BACKSIDE OF
THE LOW ON MONDAY...WITH WRAP AROUND SNOW SHOWERS CONTINUING.
ANOTHER STRONG SYSTEM WILL THEN AFFECT THE AREA TOWARD THE MIDDLE OF
NEXT WEEK...BUT THE MODELS HAVE BACKED OFF ON WIDESPREAD AND HEAVY
PRECIPITATION WITH THIS SYSTEM. STILL LOOKS LIKE IT COULD BRING SOME
ACCUMULATION...BUT THE GEM IS THE MODEL WITH THE HEAVIEST
PRECIPITATION. IN ALL...IT LOOKS LIKE GENERALLY COOLER THAN NORMAL
TEMPERATURES THROUGH THE EXTENDED TIME PERIOD. THE GFS DOES BRING A
SURFACE LOW ACROSS MN ON FRIDAY NIGHT AND SATURDAY...BUT THE ECMWF
HAS HIGH PRESSURE AT THE SAME TIME.
&&
.POINT TEMPS/POPS...
DLH 23 34 28 39 / 30 100 100 40
INL 16 38 28 38 / 0 90 100 60
BRD 25 36 27 40 / 90 100 70 40
HYR 20 38 30 42 / 50 100 90 10
ASX 19 37 31 42 / 10 100 100 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING
FOR MNZ010>012-018>021-026.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
MNZ025-033>036.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR MNZ037.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
147-148.
&&
$$
SHORT TERM...GROCHOCINSKI
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1002 AM CDT SAT APR 13 2013
.UPDATE...
THE MAIN CHALLENGE FOR THIS UPDATE TO THE FORECAST IS THE
LINGERING SNOW IN NW WISCONSIN. OBSERVATIONS FROM
IRONWOOD AND ASHLAND...THE CURRENT RADAR...AND CALLS FROM
OBSERVERS SUGGEST THIS SNOW IS LINGERING LONGER THAN PREVIOUSLY
THOUGHT IT WOULD. THE SNOW IS REDUCING VISIBILITY QUITE A BIT AT
TIMES. THE LATEST NAM AND HRRR MODELS SHOW IT THE HEAVIER SNOW
BANDS LINGERING LONGER...SO I EXTENDED THE WINTER WEATHER ADVISORY
FOR IRON AND ASHLAND COUNTIES TILL NOON. I WOULD NOT BE SURPRISED
IF SOME AREAS GET AN ADDITIONAL 1 TO 2 INCHES NEAR AND ALONG THE
GOGEBIC RANGE.
OTHERWISE...THE REST OF THE FORECAST FOR TODAY IS RELATIVELY
QUIET. I LOWERED CLOUD COVER THIS MORNING IN SOME AREAS THAT HAVE
SOME PARTIAL CLEAR...BUT I THINK THE FORECAST AREA WILL MOSTLY
HAVE CLOUDY OR MOSTLY CLOUDY SKIES TODAY.
THE FOCUS WHEN I MAKE MY NEW FORECAST THIS AFTERNOON WILL OF
COURSE BE THE NEXT SPRINGTIME WINTER STORM THAT IS POISED TO
STRIKE THE NORTHLAND SUNDAY AND SUNDAY NIGHT. COMPARED TO WHAT I
SAW IN THE 12Z MODELS YESTERDAY...THE SNOWFALL ACROSS NE MINNESOTA
IN THE 00Z MODELS SNOWFALL SEEMS TO BE LOWER THAN YESTERDAY. IF
THE NEW 12Z MODELS REMAIN FAIRLY CONSISTENT AND AGREEABLE BETWEEN
EACH OTHER...THAN WE WILL PROBABLY ISSUE WINTER STORM WARNINGS AND
ADVISORIES FOR THIS NEXT ROUND OF SNOW.
&&
.PREV DISCUSSION... /ISSUED 711 AM CDT SAT APR 13 2013/
AVIATION.../12Z TAF ISSUANCE/
THE LARGE WINTER STORM THAT MOVED THROUGH OVER THE PAST FEW DAYS
WILL GRADUALLY PULL OUT OVER THE NEXT 24 HOURS. THE RESULT WILL BE
WIDELY VARYING CLOUD HEIGHTS AND VISIBILITIES AS THE LOW MOVES
EAST AND THE CLOUDS AND SNOW SHOWERS TRY TO BREAK UP. CONDITIONS
WILL VARY BETWEEN VFR AND MVFR AND LOCALLY IFR.
SHORT TERM...
CURRENT...VERTICALLY STACKED CIRCULATION OVER ERN LAKE SUPERIOR
IS MAINTAINING A MOIST CYCLONIC FLOW OVER CWA EARLY THIS MORNING.
ABUNDANCE OF CLOUDS WITH SOME WIND AND LIGHT PRECIP HAS KEPT
TEMPS ACROSS CWA FAIRLY UNIFORM. LOWEST READINGS ARE IN THE MN
ARROWHEAD WITH TEENS ...AND 20S ELSEWHERE.
TODAY...WIDESPREAD AREA OF LIGHT SNOW ACROSS MN ZONES WILL ADVECT
EASTWARD INTO WISC ZONES THROUGH REMAINDER OF MORNING. WILL LET WSW
EXPIRE IN BAYFIELD COUNTY AT 12Z AND EXTEND ASHLAND/IRON COUNTIES
TIL 15Z. ALTHOUGH CYCLONIC FLOW WILL PERSIST SFC/ALOFT TODAY...DEEP
LAYER RH IS EXPECTED TO GRADUALLY DIMINISH. LT SNOW/SNOW SHOWERS
WILL PERSIST THROUGH MID AFTN OVER MN ZONES..AND PERHAPS UNTIL LATE
AFN OVER WISC ZONES. MAX TEMPS REMAIN WELL BLO CLIMO WITH MID 30S
PREVAILING.
TONIGHT...PROGRESSIVE FLOW ALOFT WILL ALLOW MID LVL RIDGING TO PUSH
INTO CWA FROM THE SOUTHWEST OVERNIGHT. AN ELONGATED AREA OF LOW
PRESSURE AT THE SFC WILL STRETCH FROM CTRL SD TO ERN NEB BY 12Z
SUNDAY. CLOUDS WILL INCREASE OVER SWRN CWA WITH SNOW DEVELOPING
AROUND 09Z AS AN AREA OF WARM FRONTOGENESIS INCREASES.
TOMORROW...MDLS AGREE THAT A DUAL LOBE SFC PRESS PATTERN WILL
CONTINUE TO MOVE NORTHEAST. THE NRN LOW WILL MOVE TOWARDS THE ND/SD
BORDER BY 00Z WHILE THE SECONDARY LOW WILL MIGRATE TO SERN MN. AN
AREA OF STRONG 85H FRONTOGENESIS WILL BE RESPONSIBLE FOR AN AREA OF
MODERATE INTENSITY SNOWFALL MAKING ITS WAY ACROSS MOST OF MN ZONES
EXCEPT ERN ARROWHEAD. A GENERAL 3 TO 6 INCH SNOWFALL APPEARS
INCREASING LIKELY FROM THE BRAINERD LAKES REGION TO TWIN PORTS AND
POINTS NORTH AND WEST. A TRANSITION IN PTYPE SHOULD OCCUR IN THE SRN
THIRD OF THE CWA BY AFTN AS ICE PELLETS AND RAIN BEGIN TO DEVELOP.
WITH PROSPECT FOR ACCUMULATING SNOW TO CONTINUE BEYOND THIS PERIOD
WILL LET DAY SHIFT DECIDE IF AN ADVISORY OR WARNING WILL BE ISSUED
FOR SUNDAY/SUNDAY NIGHT EVENT.
PREV DISCUSSION... /ISSUED 332 AM CDT SAT APR 13 2013/
EXTENDED...SUNDAY NIGHT THROUGH SATURDAY...
THE STRONG LOW PRESSURE SYSTEM THAT WILL MOVE THROUGH LATE IN THE
WEEKEND WILL CONTINUE TO AFFECT THE NORTHLAND INTO SUNDAY NIGHT.
THERE WILL LIKELY STILL BE SOME ACCUMULATION INTO THE
NIGHT...ESPECIALLY ACROSS NE MN. A MIX IS EXPECTED FROM EC MN INTO
PORTIONS OF NW WI...WITH MAINLY RAIN ACROSS THE FAR SE. STRONG WINDS
WILL GRADUALLY SUBSIDE AS THE SURFACE LOW MOVES INTO NORTHERN
MN...BUT STRONG NW TO W WINDS WILL THEN DEVELOP ON THE BACKSIDE OF
THE LOW ON MONDAY...WITH WRAP AROUND SNOW SHOWERS CONTINUING.
ANOTHER STRONG SYSTEM WILL THEN AFFECT THE AREA TOWARD THE MIDDLE OF
NEXT WEEK...BUT THE MODELS HAVE BACKED OFF ON WIDESPREAD AND HEAVY
PRECIPITATION WITH THIS SYSTEM. STILL LOOKS LIKE IT COULD BRING SOME
ACCUMULATION...BUT THE GEM IS THE MODEL WITH THE HEAVIEST
PRECIPITATION. IN ALL...IT LOOKS LIKE GENERALLY COOLER THAN NORMAL
TEMPERATURES THROUGH THE EXTENDED TIME PERIOD. THE GFS DOES BRING A
SURFACE LOW ACROSS MN ON FRIDAY NIGHT AND SATURDAY...BUT THE ECMWF
HAS HIGH PRESSURE AT THE SAME TIME.
&&
.POINT TEMPS/POPS...
DLH 36 23 34 28 / 30 30 100 80
INL 37 16 38 28 / 30 0 90 90
BRD 38 25 36 27 / 30 90 100 70
HYR 38 20 38 30 / 40 50 100 80
ASX 37 19 37 31 / 60 10 100 100
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING
FOR MNZ010>012-018>021-026.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
MNZ025-033>036.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR MNZ037.
WI...WINTER WEATHER ADVISORY UNTIL NOON CDT TODAY FOR WIZ003-004.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
147-148.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1202 AM CDT SAT APR 13 2013
.AVIATION...06Z TAF ISSUANCE...
WIDESPREAD LIGHT SNOW ACROSS ALL TERMINAL SITES FOR THE FIRST FEW
HOURS OF THIS TAF PERIOD..ALONG WITH LOW VFR/HIGH MVFR CEILINGS.
LIGHT SNOW SHOULD DIMINISH FROM WEST TO EAST AFTER 12Z AT MOST
TERMINALS. A SLOW LIFTING OF CLOUD BASES IS EXPECTED TODAY.
HOWEVER..A COMBINATION OF STEEP LOW LEVEL LAPSE RATES/RESIDUAL
BOUNDARY LAYER MOISTURE MAY PRODUCE BROKEN MVFR/VFR STRATOCUMULUS
DECK BEGINNING AROUND MIDDAY ALONG WITH PERIODIC SNOW SHOWERS IN
THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 1006 PM CDT FRI APR 12 2013/
UPDATE...
CENTER OF UPPER LOW IS LOCATED JUST SOUTH OF MARQUETTE MI LATE
THIS EVENING..AND IS CONTINUING TO PULL OFF TO THE EAST. HOWEVER..
BENT-BACK AXIS OF DEFORMATION AND LOWER HEIGHTS EXTENDS WEST FROM
THE LOW CENTER ACROSS NRN MINNESOTA..AND THE EASTWARD PROGRESS IS
BEING HAMPERED BY THE AMPLIFYING S/W TROF SLIDING EWD ACROSS NRN
IOWA AT THE MOMENT. THUS..WEAK FORCING FOR ASCENT IS LIKELY TO
PERSIST FOR EVEN LONGER THAN PREVIOUSLY THOUGH OVERNIGHT..WITH
LIGHT SNOW PERSISTING ACROSS MUCH OF EASTERN MN AND NW WISCONSIN.
WHILE PRECIP RATES WILL BE MUCH LESS THAN OBSERVED EARLIER
TODAY..HIGHER SNOW-LIQUID RATIOS AS COLUMN COOLS MAY STILL RESULT
IN ANOTHER FEW INCHES IN SOME OF THE FAVORED TERRAIN AREAS OF THE
BAYFIELD PENINSULA AND GOGEBIC RANGE WHERE NE WINDS WILL STILL
PROVIDE SOME ADDED MOISTURE FROM LK SUPERIOR.
WINDS HAVE DIMINISHED MARKEDLY FROM THIS AFTERNOON..AND WITH THE
CESSATION OF STRONGER WINDS AND HEAVIER SNOWFALL RATES OVER THE
ARROWHEAD..WE HAVE ALLOWED THE WINTER STORM WARNING TO EXPIRE AS
SCHEDULED AT 10 PM. HOWEVER..WE HELD ON TO WARNINGS/ADVISORIES FOR
THE SNOWBELT AREAS OF NW WISCONSIN.
OTHERWISE..WINDS SHOULD CONTINUE TO DIMINISH OVERNIGHT ALONG WITH
CLOUDY SKIES PERSISTING. UPDATES TO GRIDS AND ALL ASSOCIATED TEXT
PRODUCTS HAVE BEEN SENT.
PREV DISCUSSION... /ISSUED 345 PM CDT FRI APR 12 2013/
SHORT TERM...THROUGH SATURDAY.
WATER VAPOR SHOWS THE UPPER LOW MOVING NORTHEAST ACROSS NORTHERN
WISCONSIN THIS AFTERNOON...AND IT IS FORECAST TO MOVE OVER
EASTERN LAKE SUPERIOR TONIGHT...AND CONTINUE EAST ON SATURDAY.
LIGHT SNOW WILL LINGER TONIGHT...BUT BE MOST WIDESPREAD THROUGH
THE EVENING HOURS. INTENSITY OVERALL WILL BE LIGHT...BUT THERE
WILL BE PERIODS OF MODERATE SNOW WITH VSBYS DOWN TO AROUND A MILE
FOR A TIME. WE WENT WITH ADDITIONAL SNOWFALL AROUND AN INCH FOR
MOST AREAS...BUT WENT A BIT HIGHER OVER PORTIONS OF THE ARROWHEAD
AND ALONG THE SOUTH SHORE. THE SOUTH SHORE WILL GET INTO LAKE
ENHANCED SNOWFALL TONIGHT AS WINDS TURN NORTHERLY AND WITH 850MB
TEMPS FORECAST TO DROP TO AROUND -12C AND INVERSION LEVELS
INCREASE. THE SOUTH SHORE WILL HAVE TO BE WATCHED CLOSELY...IF
STABILITY IS LOWER THAN EXPECTED...SNOW RATES COULD GET HEAVY AT
TIMES ACROSS THE SNOWBELT OF ASHLAND/IRON COUNTIES. THE OTHER AREA
WE`LL HAVE TO MONITOR IS ACROSS NORTH CENTRAL DOUGLAS
COUNTY...SOUTHWEST TOWARD SOUTHEAST CARLTON COUNTIES. AS LOW LEVEL
WINDS BACK TO NORTHWEST TONIGHT...WE COULD SEE A GRAVITY WAVE
INDUCED BAND OF ENHANCED SNOWFALL DEVELOP. LOOKING AT A RAP CROSS
SECTION...A STRONG SIGNAL IS NOT SEEN ATTM.
LIGHT SNOW OR FLURRIES WILL LINGER INTO SATURDAY
MORNING...PARTICULARLY OVER THE EASTERN HALF OF THE CWA DUE TO THE
SLOW DEPARTURE OF THE UPPER LOW. HOWEVER...ADDITIONAL SNOWFALL
WILL BE QUITE LIGHT IF ANYTHING MEASURES AT ALL.
WE EXPECT HIGHS SATURDAY TO REACH THE 35 TO 40 FOR MOST AREAS.
LONG TERM...SATURDAY NIGHT - FRIDAY.
THE FOCUS IN THIS FORECAST IS THE WINTER STORM SYSTEM THAT IS
EXPECTED TO AFFECT THE NORTHLAND LATE SATURDAY NIGHT THROUGH SUNDAY
NIGHT. THE MODELS CONTINUE TO INDICATE THAT A POTENT MID/UPPER LOW
PRESSURE SYSTEM AND ITS ASSOCIATED LOW PRESSURE SYSTEM AT THE
SURFACE WILL MOVE THROUGH THE NORTHERN PLAINS SUNDAY AND MOVE INTO
ONTARIO MONDAY.THE MODELS SEEM TO HAVE INCREASED THEIR SNOWFALL FOR
THIS SYSTEM FOR LATE SATURDAY NIGHT THROUGH MONDAY MORNING...AND
TRENDED A LITTLE COLDER. I STILL THINK THERE MAY BE A WINTRY MIX
ACROSS THE SOUTHERN FORECAST AREA DURING THE LATE MORNING AND AT
LEAST THE AFTERNOON DUE TO NOT ONLY WARMER SURFACE
TEMPERATURES...BUT INCREASING TEMPERATURES ALOFT. I DO NOT SEE ANY
SIGNIFICANT RISK OF FREEZING RAIN BASED ON THE SOUNDINGS...BUT WE
WILL NEED TO CONTINUALLY CHECK INTO THIS. THE WINTRY MIX ACROSS THE
SOUTH WILL LIKELY PREVENT MUCH ACCUMULATION OF SNOW...SO MOST OF THE
CONCERN IS FOR NE MINNESOTA FOR HEAVY SNOW WHERE TEMPERATURES WILL
BE COLDER. THIS STORM SYSTEM IS LOOKING MORE AND MORE LIKELY THAT IT
WILL BRING AT LEAST A WIDESPREAD 6 TO 8 INCHES ACROSS NE
MINNESOTA...ESPECIALLY NORTH OF HIGHWAY 2. SOME ARES OF FAR NORTHERN
MINNESOTA MAY GET UP TO 10 INCHES. I MAY BE ON THE HIGH SIDE WITH
THE STORM TOTAL SNOWFALL...SO I DO NOT IMAGINE AT THIS POINT THAT
THIS STORM WOULD YIELD MUCH MORE SNOW THAN THIS.
LIGHT SNOW COULD LINGER ACROSS NE MINNESOTA MONDAY INTO TUESDAY IN
THE WAKE OF THE STORM SYSTEM. BEYOND TUESDAY...PREVIOUS MODEL RUNS
HAD BEEN INDICATING THE POTENTIAL FOR ANOTHER WINTRY-WEATHER SYSTEM
MID TO LATE WEEK...BUT IT WAS GOING TO BE DEPENDENT THE TRACK OF THE
ASSOCIATED LOW PRESSURE SYSTEM. THE LATEST GFS AND ECMWF ARE BACKING
OFF ON HAVING THIS SYSTEM AFFECTING THE NORTHLAND IN THAT THEY HAVE
THE LOW TRACK VERY FAR SOUTH...BASICALLY FROM THE SOUTHERN PLAINS TO
MICHIGAN. HOWEVER...THE GEM HAS A TRACK THAT IS SIGNIFICANTLY
FARTHER NORTH AND STILL SUGGESTS THE POTENTIAL TO BRING SIGNIFICANT
SNOWFALL TO PARTS OF THE NORTHLAND MID TO LATE WEEK. UNTIL AND IF
THE GEM BACKS OFF ON THE SYSTEM...THAT WE STILL NEED TO CARRY PCPN
CHANCES FOR THE MID TO LATE WEEK.
OVERALL THE COLD WEATHER PATTERN IS EXPECTED TO CONTINUE OVER THE
UPCOMING WEEK.
&&
.POINT TEMPS/POPS...
DLH 30 23 37 21 / 100 90 30 10
INL 30 19 38 17 / 100 70 20 0
BRD 32 24 38 24 / 70 70 30 50
HYR 34 20 38 20 / 100 80 40 10
ASX 30 24 37 17 / 100 90 60 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR MNZ025-033>036.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR MNZ010-011-018-019-026-037.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR MNZ012-020-021.
WI...WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY FOR WIZ003-004.
WINTER STORM WARNING UNTIL 7 AM CDT SATURDAY FOR WIZ002.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT SATURDAY FOR LSZ121-147-148.
SMALL CRAFT ADVISORY UNTIL 4 AM CDT SATURDAY FOR LSZ140>146.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
356 AM EDT SAT APR 13 2013
.SYNOPSIS...
THINGS WILL BE MAINLY DRY TO START OFF TODAY. HOWEVER...UPPER
LEVEL LOW PRESSURE WILL SHIFT FROM THE NORTHERN GREAT LAKES TO THE
NORTHEAST OVER THE COURSE OF THE WEEKEND. PASSING DISTURBANCES IN
THE VICINITY OF THIS SYSTEM WILL CAUSE SCATTERED SHOWERS MAINLY IN
CENTRAL NEW YORK LATE TODAY THROUGH TONIGHT...BEFORE DIMINISHING
SUNDAY MORNING. RAIN SHOWERS WILL MIX WITH SNOW SHOWERS TONIGHT
AND EARLY SUNDAY. HIGH PRESSURE WILL BUILD IN LATE SUNDAY...WITH
WARMER WEATHER COMING FOR THE FOLLOWING SEVERAL DAYS.
&&
.NEAR TERM /THROUGH TONIGHT/...
215 AM UPDATE...
WITH SHORTWAVE EXITING THE AREA AND MUCH DRIER AIR MASS MOVING
IN...SPOTTY SHOWERS AND DRIZZLE ARE QUICKLY COMING TO AN END FOR
THE REMAINDER OF THE PREDAWN HOURS. INCOMING AIR MASS WILL HAVE
PRECIPITABLE WATER VALUES OF ONLY BETWEEN A THIRD AND A HALF INCH
DURING THE DAY TODAY. I CUT BACK AND/OR DELAYED POPS SIGNIFICANTLY
FOR MOST OF TODAY...WHICH WILL BE MAINLY DRY YET STILL WITH FAIR
AMOUNT OF CLOUDS. INVERTED-V IN LOWER LEVELS OF SOUNDINGS
INDICATE THAT IN ADDITION TO COVERAGE OF SHOWERS BEING VERY
LIMITED UNTIL LATE TODAY /FROM HAVING TO FIGHT THE DRY
AIR/...20-25 MPH GUSTS SHOULD HAVE NO PROBLEM MIXING DOWN THIS
AFTERNOON AND WOULD NOT BE SURPRISED IF A FEW GUSTS TOP 30 MPH
NEAR THE SCATTERED SHOWERS LATE TODAY.
MODELS AGREE THOUGH THAT A FAIRLY STRONG SHORTWAVE WILL SWING
THROUGH LATE TODAY WITH PERHAPS ANOTHER DECENT ONE TONIGHT. THIS
WILL STEEPEN LAPSE RATES WHICH ALONG WITH INCREASE IN MOISTURE
WITHIN LOWEST 10 KFT...SHOULD YIELD SCATTERED SHOWERS MAINLY IN
CENTRAL NEW YORK WITH NOMINAL AID OF GREAT LAKES MOISTURE. 850MB
TEMPERATURES DO NOT EVEN REACH MINUS-10 CELSIUS...SO AMOUNT OF
HELP FROM THE LAKES WILL BE LIMITED. WITH 925MB TEMPERATURES ALSO
DROPPING BELOW FREEZING...THE SCATTERED RAIN SHOWERS SHOULD MIX
WITH/CHANGE OVER TO SNOW SHOWERS. WHERE SNOW SHOWERS OCCUR THOUGH
AMOUNTS WILL BE VERY LIGHT...PERHAPS UP TO ABOUT AN INCH TOWARDS
TUG HILL IN NORTHERN ONEIDA COUNTY AND JUST TRACE TO FEW TENTHS
ELSEWHERE /MAINLY HIGH ELEVS/.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
355 AM UPDATE...
IT TAKES ALL DAY SUNDAY FOR 540 DECAMETER 1000-500MB THICKNESS
LINE TO PASS THROUGH THE AREA. COOL AND SOMEWHAT GUSTY WNW FLOW
WILL SUBSIDE BE LATE IN THE DAY AS SURFACE HIGH BUILDS IN. MODEL
SOUNDINGS SUGGEST ENOUGH MOISTURE TRAPPED UNDER DEVELOPING
SUBSIDENCE INVERSION...FOR AT LEAST SCATTERED CUMULUS DECK IF NOT
EVEN BROKEN. SO WHILE SOME SUNSHINE SHOULD OCCUR...IT WILL BE
TEMPERED BY FAIR AMOUNT OF CLOUDS. OVERALL...AFTER LOW CHANCE OF
MIXED SNOW/RAIN SHOWERS IN MAINLY THE NORTHEASTERN ZONES EARLY
SUNDAY MORNING...LOOKING AT A MAINLY DRY DAY WITH HIGHS FALLING
SHORT OF CLIMATOLOGY BY ROUGHLY 5 OR SO DEGREES. THAT BEING
SAID...THE PATTERN IS ABOUT TO TURN QUICKLY.
HIGH PRESSURE WILL SHIFT EAST SUNDAY NIGHT...AS ELEVATED WARM
FRONT ALOFT PASSES WITH A BAND OF CLOUDS /TOO MUCH DRY AIR IN LOW
LEVELS FOR PRECIPITATION/. UPPER RIDGE AXIS MOVES IN
MONDAY...WHILE AT THE SURFACE A BROAD WARM SOUTH-SOUTHEAST RETURN FLOW
WILL DEVELOP. USED MIX DOWN TOOL FROM 900MB ALONG WITH SOME BLEND
IN OF LATEST GUIDANCE NUMBERS TO DERIVE HIGHS NEAR 70 IN LAKE
PLAIN /HELPED BY DOWNSLOPING/ WITH MAINLY 60S ELSEWHERE. COOLEST
TEMPERATURES WILL ACTUALLY WITH THE UPSLOPE FLOW AGAINST THE
POCONOS AND CATSKILLS...INCLUDING SOME MARINE INFLUENCE...WITH SOME
PLACES NOT REACHING 60 DEGREES. REGARDLESS...QUITE A BIT WARMER
THAN TEMPERATURES THIS WEEKEND.
MODELS INDICATE FRONT APPROACHING FROM NORTHWEST AND SLOWING MONDAY
NIGHT...WILL HAVE A DIFFICULT TIME REACHING THE AREA. POPS FOR
THEN HAVE BEEN DELAYED AND LOWERED INTO SLIGHT TO LOW CHANCE
ACCORDINGLY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
3 PM FRIDAY UPDATE...
FOLLOWED WPC GUIDANCE WITH A PATTERN THAT LOOKS SIMILAR TO THIS
PAST WEEK. EARLY IN THE PERIOD RIDGING IN THE EAST AND A TROF OVER
THE DESERT SOUTHWEST WILL KEEP US WITH A WARM FLOW OF AIR WITH
850S AROUND 12C TUESDAY MORNING. EVENTUALLY BOTH THE EURO AND GFS
SHOW A COLD FRONT MOVING INTO OUR AREA THEN WAFFLING BACK AND
FORTH THROUGH THE WEEK. TIMING AND PLACEMENT DIFFERENCES EXIST BUT
THE OVERALL IDEA OF A WET AND UNSETTLED PATTERN LOOK SOLID. TEMPS
ARE GENERALLY IN THE 60S AND THIS IS A GOOD START FOR NOW. AS WE
GET CLOSER AND THE DETAILS GET IRONED OUT WE MAY AGAIN SEE LARGE
NORTH/SOUTH TEMPERATURE DIFFERENCES DUE TO THE FRONTAL POSITION.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
A PUSH OF DRY AIR ALONG A COLD FRONT HAS ARRIVED AT OUR NY
TERMINALS, BRINGING CEILINGS UP TO VFR. THE FRONT IS GETTING CLOSE
TO AVP, BUT IR SAT PROGS THE DRY AIR PUSH TO ARRIVE JUST PRIOR TO
7Z. FOR THIS REASON THE AVP TERMINAL IS FORECAST TO HAVE TEMPO IFR
CEILINGS FOR 1-2 HOURS.
SOME CONCERN THAT BGM/RME MAY FLIRT WITH IFR OVERNIGHT DUE TO LOW
TDD VALUES. HOWEVER THERE IS QUITE A BIT OF MIXING, AND LATEST
BUFKIT RAP DATA SHOWS NO IFR CLOUD POTENTIAL.
MVFR CLOUDS ARE PROGGED TO REFORM BETWEEN 10Z AND 14Z. CEILINGS
THIS AFTERNOON WILL BE BETWEEN 2500 AND 4000 FEET. MVFR
RESTRICTIONS IN SHOWER ACTIVITY ARE POSSIBLE TONIGHT.
.OUTLOOK...
SAT NGT TO SUN...MAINLY VFR BUT PSBL MVFR IN MIXED SHWRS.
SUN NGT TO MON...VFR.
MON NGT TO WED...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MDP
SHORT TERM...MDP
LONG TERM...HEDEN
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
212 AM EDT SAT APR 13 2013
.SYNOPSIS...
THINGS WILL BE MAINLY DRY TO START OFF TODAY. HOWEVER...UPPER
LEVEL LOW PRESSURE WILL SHIFT FROM THE NORTHERN GREAT LAKES TO THE
NORTHEAST OVER THE COURSE OF THE WEEKEND. PASSING DISTURBANCES IN
THE VICINITY OF THIS SYSTEM WILL CAUSE SCATTERED RAIN AND SNOW SHOWERS
LATE TODAY THROUGH TONIGHT...BEFORE DIMINISHING SUNDAY MORNING.
AMOUNTS WILL BE LIGHT AND MAINLY IN CENTRAL NEW YORK. HIGH
PRESSURE WILL BUILD IN LATE SUNDAY...WITH WARMER WEATHER COMING FOR
THE FOLLOWING SEVERAL DAYS.
&&
.NEAR TERM /THROUGH TONIGHT/...
215 AM UPDATE...
WITH SHORTWAVE EXITING THE AREA AND MUCH DRIER AIR MASS MOVING
IN...SPOTTY SHOWERS AND DRIZZLE ARE QUICKLY COMING TO AN END FOR
THE REMAINDER OF THE PREDAWN HOURS. INCOMING AIR MASS WILL HAVE
PRECIPITABLE WATER VALUES OF ONLY BETWEEN A THIRD AND A HALF INCH
DURING THE DAY TODAY. I CUT BACK AND/OR DELAYED POPS SIGNIFICANTLY
FOR MOST OF TODAY...WHICH WILL BE MAINLY DRY YET STILL WITH FAIR
AMOUNT OF CLOUDS. INVERTED-V IN LOWER LEVELS OF SOUNDINGS
INDICATE THAT IN ADDITION TO COVERAGE OF SHOWERS BEING VERY
LIMITED UNTIL LATE TODAY /FROM HAVING TO FIGHT THE DRY
AIR/...20-25 MPH GUSTS SHOULD HAVE NO PROBLEM MIXING DOWN THIS
AFTERNOON AND WOULD NOT BE SURPRISED IF A FEW GUSTS TOP 30 MPH
NEAR THE SCATTERED SHOWERS LATE TODAY.
MODELS AGREE THOUGH THAT A FAIRLY STRONG SHORTWAVE WILL SWING
THROUGH LATE TODAY WITH PERHAPS ANOTHER DECENT ONE TONIGHT. THIS
WILL STEEPEN LAPSE RATES WHICH ALONG WITH INCREASE IN MOISTURE
WITHIN LOWEST 10 KFT...SHOULD YIELD SCATTERED SHOWERS MAINLY IN
CENTRAL NEW YORK FROM NOMINAL AID OF GREAT LAKES MOISTURE. 850MB
TEMPERATURES DO NOT EVEN REACH MINUS-10 CELSIUS...SO AMOUNT OF
HELP FROM THE LAKES WILL BE LIMITED. WITH 925MB TEMPERATURES ALSO
DROPPING BELOW FREEZING...THE SCATTERED RAIN SHOWERS SHOULD MIX
WITH/CHANGE OVER TO SNOW SHOWERS. AMOUNTS THOUGH WILL BE VERY
LIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
315 PM UPDATE...
SUNDAY WL LKLY RESULT IN HIGHS BLO CLIMO ACRS NY STATE WITH COLD
AIR FILTERING IN FM CANADA ON NRLY FLOW WITH SFC HIPRES BUILDING
IN FM THE WEST. H8 TEMPS EXPECTED TO DROP TO BTWN -6C AND -9C.
EXPECT WINDS TO BE OUT OF THE WEST BUT LITTLE CHC FOR LK EFFECT
OVR FAR NRN ZONES WITH DELTA T`S EARLY IN THE DAY ARND 12C AND HV
KEPT LO-SLGT CHC POPS THRU 18Z SUNDAY.
HIPRES WL END THE SHORT TERM WITH NO WX EXPECTED FM ABOUT SUN AFTN
THRU THE DAY MONDAY. TEMPS WL MODERATE THRU EARLY NEXT WEEK WITH
MAXES PROGGED TO BE IN THE 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
3 PM UPDATE...
FOLLOWED WPC GUIDANCE WITH A PATTERN THAT LOOKS SIMILAR TO THIS
PAST WEEK. EARLY IN THE PERIOD RIDGING IN THE EAST AND A TROF OVER
THE DESERT SOUTHWEST WILL KEEP US WITH A WARM FLOW OF AIR WITH
850S AROUND 12C TUESDAY MORNING. EVENTUALLY BOTH THE EURO AND GFS
SHOW A COLD FRONT MOVING INTO OUR AREA THEN WAFFLING BACK AND
FORTH THROUGH THE WEEK. TIMING AND PLACEMENT DIFFERENCES EXIST BUT
THE OVERALL IDEA OF A WET AND UNSETTLED PATTERN LOOK SOLID. TEMPS
ARE GENERALLY IN THE 60S AND THIS IS A GOOD START FOR NOW. AS WE
GET CLOSER AND THE DETAILS GET IRONED OUT WE MAY AGAIN SEE LARGE
NORTH/SOUTH TEMPERATURE DIFFERENCES DUE TO THE FRONTAL POSITION.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A PUSH OF DRY AIR ALONG A COLD FRONT HAS ARRIVED AT OUR NY
TERMINALS, BRINGING CEILINGS UP TO VFR. THE FRONT IS GETTING CLOSE
TO AVP, BUT IR SAT PROGS THE DRY AIR PUSH TO ARRIVE JUST PRIOR TO
7Z. FOR THIS REASON THE AVP TERMINAL IS FORECAST TO HAVE TEMPO IFR
CEILINGS FOR 1-2 HOURS.
SOME CONCERN THAT BGM/RME MAY FLIRT WITH IFR OVERNIGHT DUE TO LOW
TDD VALUES. HOWEVER THERE IS QUITE A BIT OF MIXING, AND LATEST
BUFKIT RAP DATA SHOWS NO IFR CLOUD POTENTIAL.
MVFR CLOUDS ARE PROGGED TO REFORM BETWEEN 10Z AND 14Z. CEILINGS
THIS AFTERNOON WILL BE BETWEEN 2500 AND 4000 FEET. MVFR
RESTRICTIONS IN SHOWER ACTIVITY ARE POSSIBLE TONIGHT.
.OUTLOOK...
SAT NGT TO SUN...MAINLY VFR BUT PSBL MVFR IN MIXED SHWRS.
SUN NGT TO MON...VFR.
MON NGT TO WED...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...MDP
SHORT TERM...PVN
LONG TERM...HEDEN
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
136 AM EDT SAT APR 13 2013
.SYNOPSIS...
UNSETTLED WEATHER EXPECTED THROUGH SUNDAY AS AN UPPER LEVEL
DISTURBANCE REMAINS ACROSS THE NORTHEASTERN UNITED STATES. HIGH
PRESSURE WILL BUILD LATE SUNDAY WITH TEMPERATURES MODERATING
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
930 PM UPDATE...H5 SHORT WAVE MOVING FROM NORTHWEST PA INTO
CENTRAL NY IS GENERATING MORE SCATTERED RAIN SHOWERS OVER THE
REGION. INCREASED SHORT TERM POPS TO REFLECT THIS BUT EXPECT ACTIVITY
TO DIMINISH AGAIN AFTER MIDNIGHT AS WAVE MOVES THROUGH. CURRENT
FORECAST IN GREAT SHAPE JUST NEAR TERM POP/TEMP ADJUSTMENTS.
315 PM UPDATE.. WIDESPREAD RAIN HAS MOVED THROUGH THE CWA EARLIER
THAN EXPECTED TODAY WITH MAINLY LIGHT SHOWERS AND DRIZZLE LEFT
OVER. OCCLUDED FRONT PROGGED TO MV THRU THIS EVNG WITH A LINE OF
SHOWERS ACCOMPANYING IT THRU ABOUT MIDNIGHT. HRRR HAS FAIRLY GOOD
HANDLE ON LINE OF SHOWERS ALONG FRONT AND EXPECT THIS TO CONTINUE
TO PROGRESS THRU THE AREA TONIGHT. SHOWERS LOOK TO COME TO AN END
BY ABOUT 06Z AS S/WV CURRENTLY ACRS SRN ILLINOIS PUSHES THRU THE
REGION.
BNDRY LYR EXPECTED TO RMN WARM ENUF FOR RAIN SHOWERS UP THRU ABOUT
06Z BFR COLD AIR WORKS INTO THE LOWEST LEVELS. CHC OF SNOW SHOWERS
WL LKLY BE CONFINED TO ELEVATIONS ABV 1500FT AS LOW LYRS RMN WARM.
SKIES WL BCM PRTLY CLDY FM THE SOUTH TWD DAYBREAK AND MIN TEMPS WL
RMN IN THE MID-UPR 30S TO ARND 40F ACRS FAR SRN ZONES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
315 PM UPDATE...
YET ANOTHER S/WV WL ROTATE THRU SAT AFTN AND KEEP THE CHC FOR
SHOWERS GOING. EXPECTING LESS THAN A TENTH OF AN INCH THRU THE DAY
TOMORROW. WITH PSUNNY SKIES EXPECTED TOMORROW ACROSS MAJORITY OF CWA
TEMPS WL RISE TO AROUND 50 DEGREES EXCEPT THEY MAY STAY DOWN IN THE
40S ACRS THE NORTH.
SUNDAY WL LKLY RESULT IN HIGHS BLO CLIMO ACRS NY STATE WITH COLD AIR
FILTERING IN FM CANADA ON NRLY FLOW WITH SFC HIPRES BUILDING IN FM
THE WEST. H8 TEMPS EXPECTED TO DROP TO BTWN -6C AND -9C. EXPECT
WINDS TO BE OUT OF THE WEST BUT LITTLE CHC FOR LK EFFECT OVR FAR NRN
ZONES WITH DELTA T`S EARLY IN THE DAY ARND 12C AND HV KEPT LO-SLGT
CHC POPS THRU 18Z SUNDAY.
HIPRES WL END THE SHORT TERM WITH NO WX EXPECTED FM ABOUT SUN AFTN
THRU THE DAY MONDAY. TEMPS WL MODERATE THRU EARLY NEXT WEEK WITH
MAXES PROGGED TO BE IN THE 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
3 PM UPDATE...
FOLLOWED WPC GUIDANCE WITH A PATTERN THAT LOOKS SIMILAR TO THIS
PAST WEEK. EARLY IN THE PERIOD RIDGING IN THE EAST AND A TROF OVER
THE DESERT SOUTHWEST WILL KEEP US WITH A WARM FLOW OF AIR WITH
850S AROUND 12C TUESDAY MORNING. EVENTUALLY BOTH THE EURO AND GFS
SHOW A COLD FRONT MOVING INTO OUR AREA THEN WAFFLING BACK AND
FORTH THROUGH THE WEEK. TIMING AND PLACEMENT DIFFERENCES EXIST BUT
THE OVERALL IDEA OF A WET AND UNSETTLED PATTERN LOOK SOLID. TEMPS
ARE GENERALLY IN THE 60S AND THIS IS A GOOD START FOR NOW. AS WE
GET CLOSER AND THE DETAILS GET IRONED OUT WE MAY AGAIN SEE LARGE
NORTH/SOUTH TEMPERATURE DIFFERENCES DUE TO THE FRONTAL POSITION.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A PUSH OF DRY AIR ALONG A COLD FRONT HAS ARRIVED AT OUR NY
TERMINALS, BRINGING CEILINGS UP TO VFR. THE FRONT IS GETTING CLOSE
TO AVP, BUT IR SAT PROGS THE DRY AIR PUSH TO ARRIVE JUST PRIOR TO
7Z. FOR THIS REASON THE AVP TERMINAL IS FORECAST TO HAVE TEMPO IFR
CEILINGS FOR 1-2 HOURS.
SOME CONCERN THAT BGM/RME MAY FLIRT WITH IFR OVERNIGHT DUE TO LOW
TDD VALUES. HOWEVER THERE IS QUITE A BIT OF MIXING, AND LATEST
BUFKIT RAP DATA SHOWS NO IFR CLOUD POTENTIAL.
MVFR CLOUDS ARE PROGGED TO REFORM BETWEEN 10Z AND 14Z. CEILINGS
THIS AFTERNOON WILL BE BETWEEN 2500 AND 4000 FEET. MVFR
RESTRICTIONS IN SHOWER ACTIVITY ARE POSSIBLE TONIGHT.
.OUTLOOK...
SAT NGT TO SUN...MAINLY VFR BUT PSBL MVFR IN MIXED SHWRS.
SUN NGT TO MON...VFR.
MON NGT TO WED...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN/RRM
SHORT TERM...PVN
LONG TERM...HEDEN
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
726 PM CDT SUN APR 14 2013
.UPDATE...
ISSUED AT 721 PM CDT SUN APR 14 2013
UPPER LOW OVER NORTHEAST SOUTH DAKOTA NEAR ABERDEEN-HURON WITH
MAIN LOW LOCATED SOUTH OF ABERDEEN AND WEST OF WATERTOWN NEAR
REDFIELD. THIS HANDLED WELL BY RAP AND WILL USE IT FOR THE EVE
FCST IN SHOWING IT TAKING A SLOW TRACK NORTHEAST TOWARD FERGUS
FALLS BY 09Z THEN TO EAST OF INL MONDAY MIDDAY. SNOW WILL CONTINUE
TOS SLOWLY MOVE NORTH WITH THIS SYSTEM AND SNOW BANDS WILL WRAP
AROUND THE SYSTEM ESP OVER ERN ND ALL NIGHT...THOUGH DRY SLOT WILL
GIVE LIGHT PRECIP AND SOME SLEET AT TIMES IN WCNTRL MN THIS EVE.
ADJUSTED SNOW STORM TOTALS A BIT BUT REPORTS INDICATE VARYING
AMOUNTS OF SNOW IN SHORT DISTANCES IN THE FARGO AREA FROM RELIABLE
OBSERVERS AND THUS HESISTANT TO DO TOO MUCH...THOUGH THE FAR EAST
AND SOUTHEAST WILL LIKELY BARELY BRUSH 6 INCHES FOR THE STORM.
SAME GOES FOR THE FAR NORTH ALONG CANDIAN BORDER. OTHERWISE KEPT 9
OR SO IN FARGO AND 10+ WEST OF THEM. WILL DROP BLIZZARD WARNING
FOR WRN FCST AREA AS WINDS HAVE DIMINISHED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM CDT SUN APR 14 2013
THE CENTER OF THE UPPER LOW HAS CONTINUED TO EVER SO SLOWLY ROTATE
OUT OF THE ROCKIES AND INTO WESTERN SOUTH DAKOTA TODAY. WV LOOP
SHOWS THE DRY INTRUSION DIGGING INTO NEB/SD AND PLENTY OF MOISTURE
WRAPPING AROUND THE FRONT SIDE OF THE SYSTEM UP INTO CENTRAL ND.
WHILE THE PRECIP HAS BEEN VERY SLOW TO MAKE ITS WAY INTO THE
CWA...JUST REACHING FAR IN THE LAST FEW HOURS AND NOT MUCH MORE
THAN FLURRIES NORTH OF THERE YET...PRECIP SHOULD CONTINUE TO
SPREAD NORTHWARD TONIGHT.
THE MODELS ARE NOW IN FAIRLY DECENT AGREEMENT ON LIFTING THE
CENTER OF THE SFC LOW NORTHEASTWARD TONIGHT AND SKIRTING IT ALONG
OUR SOUTHEASTERN COUNTIES. THE SOUTHEASTERN COUNTIES MAY SEE THE
DRY SLOT COMING OVER THEIR AREA SO CONTINUED THE TREND OF SLIGHTLY
LOWER SNOW TOTALS IN THAT AREA. FURTHER NORTHWEST...THE PRECIP
WILL BE SLOW TO MOVE IN BUT THERE ARE SIGNS THAT THE DEFORMATION
BAND WILL BE PIVOTING OVER THE CENTRAL CWA TONIGHT AND TOMORROW.
CONTINUED TO KEEP A HEAVY BAND OF 8 TO 12 INCHES OVER ALL BUT THE
FAR SOUTHEAST AND FAR NORTHERN COUNTIES...AND EVEN THOSE PLACES
WILL PROBABLY STILL SEE MORE THAN 6 INCHES. WILL KEEP THE WINTER
STORM WARNING FOR EVERYWHERE FOR NOW.
THE NEXT QUESTION IS IF WE NEED TO EXPAND THE BLIZZARD WARNING
THAT IS IN THE SOUTHWESTERN COUNTIES A BIT MORE. FARGO WENT DOWN
TO 1/4SM VIS AND GUSTED TO 35 MPH...BUT BROADCAST MEDIA REPORTS
THAT SNOW IS LIGHTER THAN WHAT ASOS IS INDICATING AND ALSO MELTING
ON THE ROADS. WITH CROSS VALLEY FLOW THIS EVENING THINK THAT THERE
WILL BE LESS MOMENTUM GOING DOWN THE RED RIVER VALLEY THAN COULD
BE WITH NORTH WINDS. WILL HOLD OFF ON EXPANDING THE BLIZZARD FOR
NOW BUT WILL KEEP AN EYE ON THE SOUTHERN COUNTIES FOR LOW VIS AND
HIGH WINDS.
THE UPPER LOW LIFTS OFF INTO SOUTHERN ONTARIO DURING THE DAY
TOMORROW. DEFORMATION BAND PRECIP SHOULD CONTINUE OVER THE
NORTHERN COUNTIES FOR MUCH OF THE DAY SO CONTINUED TO KEEP HIGH
POPS GOING IN THAT AREA...BUT STARTED TO LOWER THEM A BIT IN THE
SOUTH. THINK THAT ONLY LIGHT LINGERING SNOW WILL REMAIN AFTER 18Z
ON MONDAY SO WILL KEEP THE HEADLINE EXPIRATION WE HAVE GOING FOR
NOW AND JUST LET LATER SHIFTS EXTEND IT.
MONDAY NIGHT SHOULD BE A BIT MORE QUIET WITH THE UPPER LOW FURTHER
OFF TO THE NORTHEAST AND THE NEXT TROUGH DIGGING INTO THE WESTERN
CONUS. HIGH PRESSURE BUILDS DOWN AND TEMPS SHOULD REMAIN PRETTY
COLD ALTHOUGH CLOUDS WILL KEEP LOWS FROM DROPPING OUT OF THE TEENS
TO MID 20S. SOME LINGERING LIGHT SNOW WILL BE POSSIBLE ALONG THE
CANADIAN BORDER INTO MONDAY NIGHT AS A WEAK BOUNDARY BEGINS TO
MOVE DOWN. WILL KEEP LOW POPS GOING IN THAT AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 324 PM CDT SUN APR 14 2013
MAIN ISSUE FOR THE NEXT WEEK WILL BE THE DEEP TROUGH THAT MOVES
ACROSS THE NATION/S MID-SECTION WEDNESDAY NIGHT AND THURSDAY.
GFS/ECMWF RUN-TO-RUN CONTINUITY HAS BEEN GOOD...NOW BOTH SHOWING
SOME QPF CLIPPING SOUTHEAST ND INTO WEST-CENTRAL AND NORTHWEST MN.
DOES NOT APPEAR TO BE ANYWHERE NEAR AS STRONG COMPARED TO TODAY/S
STORM...BUT IT WILL BE COLD ENOUGH FOR SOME ADDITIONAL SNOW
ACCUMULATION. TOO EARLY TO FORECAST EXACT AMOUNTS...BUT SOMETHING TO
WATCH CLOSELY. 925 HPA TEMPERATURES REMAIN IN THE -2 TO -8 C RANGE
ALL WEEK...SO EXPECT WELL BELOW SEASONAL NORMALS TO CONTINUE WITH
DAYTIME HIGHS IN THE UPPER 20S TO MID 30S AND NIGHTTIME LOWS IN THE
UPPER TEENS AND 20S...FURTHER DELAYING THE PRIMARY SNOWMELT INTO
LATE APRIL AT THE EARLIEST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 721 PM CDT SUN APR 14 2013
OBVIOUSLY NIGHTMARE AVIATION FCST WITH VARIABLE VSBYS AND MIX OF
IFR AND MVFR CIGS. OVERALL IFR VSBYS WITH MVFR CIGS TO DOMINATE
MOST TAF SITES INTO MONDAY WITH THIS SYSTEM. WINDS WILL BE EAST
THE TURN MORE NORTHEAST AND NORTH IN ERN ND BY 12Z MON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
MN...WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR MNZ001>009-
013>017-022>024-027>032-040.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JR
LONG TERM...ROGERS
AVIATION...RIDDLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
116 PM CDT SAT APR 13 2013
.UPDATE...
ISSUED AT 116 PM CDT SAT APR 13 2013
NO MAJOR CHANGES PLANNED FOR THE EARLY AFTERNOON UPDATE. CLOUD
COVER IS SLOW TO DISSIPATE ACROSS NORTHWEST AND WEST CENTRAL
MN...AFFECTING TEMPERATURE RECOVERY. HOWEVER...AFTERNOON HIGHS
STILL REASONABLE AND WILL NOT CHANGE AT THIS TIME.
UPDATE ISSUED AT 955 AM CDT SAT APR 13 2013
1430 UTC WATER VAPOR LOOP SHOWS AN UPPER LOW SPINNING ACROSS LAKE
SUPERIOR AND A MUCH STRONGER VORTICITY MAXIMUM DIGGING ACROSS THE
PACIFIC NORTHWEST. IN-BETWEEN...SHORT WAVE RIDGING ALONG THE
MT/ND BORDER IS EXPECTED TO SLIDE EASTWARD TODAY FOR RELATIVELY
TRANQUIL WEATHER CONDITIONS. SURFACE RIDGE AXIS FROM THE DEVILS
LAKE BASIN DOWN THE JAMES RIVER VALLEY IS ALSO EXPECTED TO MOVE
INTO NORTHWEST MN THIS AFTERNOON AND EVENING...ALLOWING LIGHT AND
VARIABLE WIND TO INCREASE FROM THE EAST ACROSS EASTERN ND THIS
AFTERNOON. THIS SHOULD HELP DISSIPATE ANY REMAINING PATCHY FOG
FROM OVERNIGHT. LATEST RAP SUGGESTS MID-LEVEL CLOUD COVER SHOULD
SLOWLY DISSIPATE THROUGH THE DAY...BUT WITH LATEST IR SATELLITE
SHOWING CONSIDERABLE CLOUDINESS ACROSS MUCH OF THE FORECAST
AREA...WILL INCREASE CLOUD COVER THROUGH MID-AFTERNOON. FOR THOSE
AREAS NOT CURRENTLY SUNNY...EXPECT AT LEAST FILTERED SUNSHINE
ALONG AND EAST OF THE VALLEY BY LATE THIS AFTERNOON. FOR THE FAR
WESTERN FORECAST AREA...LOWERED AFTERNOON HIGHS A FEW DEGREES TO
ACCOUNT FOR CURRENT TEMPERATURES ONLY IN THE TEENS AND OVERCAST
SKIES WHICH WILL LIMIT OVERALL RECOVERY.
WILL NOT MAKE ANY CHANGES FOR NOW TO TONIGHT/TOMORROWS STORM AND
ASSOCIATED HEADLINES AND RE-EVALUATE WITH THIS AFTERNOON/S
FORECAST.
UPDATE ISSUED AT 620 AM CDT SAT APR 13 2013
WE WILL ISSUE A WINTER STORM WARNING FOR THE ENTIRE FORECAST AREA
WITH THIS UPDATE. CONFIDENCE IS HIGH WITH A MAJOR WINTER STORM FROM
LATE TONIGHT THROUGH SUNDAY NIGHT. EXPECT FAIRLY WIDESPREAD SNOW
TOTALS RANGING FROM 6 TO 10 INCHES IN THE NORTHERN 2/3 OF THE
REGION WITH LOWER TOTALS IN THE FAR SOUTH WHERE SOME FREEZING
RAIN/SLEET IS POSSIBLE LATE TONIGHT AND SUNDAY MORNING. SOME AREAS
COULD LOCALLY REACH 1 FOOT MAINLY FROM THE DEVILS LAKE BASING INTO
NORTHEAST ND AND NW ND WHERE THE DEFORMATION SNOW BAND SETS UP.
EXPECT THE MOST SIGNIFICANT IMPACTS LATE TONIGHT IN THE FAR
SOUTH...AND SUNDAY INTO SUNDAY EVENING FURTHER NORTH. WINDS WILL
ALSO INCREASE AND GUST OVER 35 MPH AT TIMES IN THE VALLEY...PRODUCING
CONSIDERABLE BLOWING AND DRIFTING SNOW AND REDUCED VSBYS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 340 AM CDT SAT APR 13 2013
THE MAIN CHALLENGE WILL BE UPCOMING STORM FOR LATE SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MODELS ARE COMING INTO GOOD AGREEMENT
OVERALL...WITH STILL A FEW DETAILS TO IRON OUT.
FOR TODAY...EXPECT SOME LINGERING SNOW SHOWERS/FLURRIES MAINLY IN
THE FAR EAST THIS MORNING. OTHERWISE...SOME CLEARING IS EXPECTED
BY AFTERNOON BUT TEMPS WILL REMAIN WELL BELOW NORMAL.
FOR TONIGHT...EXPECT INCREASING CLOUDS AND PRECIP SHOULD QUICKLY
DEVELOP IN THE SOUTH AROUND OR SHORTLY AFTER 06Z. A DYNAMIC STORM
SYSTEM WILL SPREAD A BAND OF WAA INDUCED SNOW WITH SOME FREEZING
RAIN/SLEET IN THE FAR SOUTH.
ON SUNDAY...A WIDESPREAD BAND OF SNOW...HEAVY AT TIMES...WILL
DEVELOP/SPREAD SLOWLY NORTH AND EAST. THERE COULD STILL BE SOME
RAIN MIXING IN THE FAR SOUTH AND EAST. VERTICAL MOTION FIELDS ARE
STRONG...WITH DEEP LAYERED OMEGA THROUGH 400 MB WITH STRONG FGEN
IN THE MID LEVELS. HIGH MOISTURE VALUES WITH PWATS AROUND 0.75
WILL ALSO ADVECT INTO THE AREA AS 850MB WINDS INCREASE TO AROUND
50 KT. IT WILL ALSO BECOME WINDY IN THE NORTH...AND EXPECT BLOWING
SNOW AND REDUCED VSBYS AS WELL. THE MAIN QUESTION WILL BE HOW MUCH
SNOW ACCUMULATES GIVEN IT IS MID APRIL. THERE SHOULD BE HIGH
ENOUGH QPF RATES TO PRODUCE SNOW RATES OF AN INCH...MAYBE 2...PER
HOUR IN SOME AREAS BY SUNDAY AFTERNOON. TEMPS SHOULD HOVER NEAR
FREEZING FOR MOST AREAS...WITH SOME MELTING POSSIBLE ON PAVEMENT
AND HIGHER ACCUMS ON GRASSY AND SNOW SURFACES. THERE COULD BE
AREAS THAT GET UP TO 6 INCHES ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT APR 13 2013
FOR SUNDAY NIGHT INTO EARLY MONDAY...SFC LOW SHOULD TRACK INTO THE
E/NE FORECAST AREAS WITH WRAPAROUND DEFORMATION SNOW BAND TO THE
NW. THE HEAVIEST SNOW SHOULD FALL FROM THE DVL BASIN INTO NE
ND...WHERE ADDITIONAL AMOUNTS OF UP TO 4 INCHES ARE POSSIBLE.
STORM TOTAL SNOW AMOUNTS BY MONDAY MORNING COULD REACH UP TO A
FOOT IN SOME AREAS...WITH FAVORED LOCATIONS FROM CENTRAL ND INTO
THE DVL BASIN TO AROUND GRAND FORKS TO HALLOCK. FOR NOW WE WILL
CONTINUE WITH THE WINTER STORM WATCH FOR THE ENTIRE REGION SINCE
THE DRY SLOT COULD REDUCE QPF AMOUNTS IN THE SOUTH A BIT. THERE IS
STILL TIME TO IRON OUT DETAILS...WITH THE LARGEST IMPACTS LATE SAT
NIGHT AND SUNDAY. A MAJOR WINTER STORM APPEARS IMMINENT THOUGH FOR
MOST AREAS AT THIS TIME.
QUIETER WEATHER IS ON TAP FOR TUESDAY AS THE UPPER LOW CONTINUES TO
PUSH AWAY. SOUTHWEST FLOW ALOFT WILL OVERSPREAD THE PLAINS AS
SHORTWAVE ENERGY DIVES INTO THE DESERT SOUTHWEST...CARVING OUT A
BROAD LONGWAVE TROUGH OVER THE WESTERN US. UNCERTAINTY STILL REMAINS
HOW THIS SYSTEM WILL EVOLVE ACROSS THE PLAINS. 00Z MODELS GENERALLY
TAKE THE SFC LOW UP INTO THE SOUTHERN GREAT LAKES BY
THURSDAY...KEEPING THE MORE SIGNIFICANT PRECIP TO THE SOUTH AND
EAST. WILL KEEP SOME POPS WITH FOR MID-WEEK GIVEN LOW CONFIDENCE
THOUGH. OTHERWISE...TEMPS WILL CONTINUE TO REMAIN WELL BELOW NORMAL
WITH 850 MB BAROCLINIC DISPLACED WELL SOUTH. EXPECT HIGHS MAINLY IN
THE 30S WITH LOWS IN THE 20S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 116 PM CDT SAT APR 13 2013
A BIT OF LINGERING STRATUS OVER KDVL SHOULD DISSIPATE IN THE NEXT
FEW HOURS...LEAVING VFR CONDITIONS EVERYWHERE FOR THE REST OF THIS
AFTERNOON AND INTO THE EVENING. CIGS AND VIS WILL BEGIN TO
DETERIORATE AFTER 06Z TONIGHT AS SNOW BEGINS TO MOVE IN FROM THE
SOUTHWEST. KFAR AND THEN KDVL AND KGFK SHOULD GO DOWN TO MVFR
CEILINGS AND VIS AROUND 1SM OR LOWER WITH EASTERLY WINDS PICKING UP
INTO THE 20 TO 25 KT RANGE WITH HIGHER GUSTS. VIS OF 1/2 TO 1/4SM
ARE NOT OUT OF THE QUESTION TOWARDS THE END OF THE PERIOD UNDER THE
HEAVIEST SNOW BANDS...BUT STILL SOME UNCERTAINTY AS TO EXACTLY WHERE
AND WHEN SO WILL JUST KEEP VIS AROUND 1SM FOR NOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING FROM 4 AM SUNDAY TO 7 AM CDT MONDAY FOR
NDZ028>030-038-039-049-052-053.
WINTER STORM WARNING FROM 10 AM SUNDAY TO 7 AM CDT MONDAY FOR
NDZ006>008-014>016-024-026-027-054.
MN...WINTER STORM WARNING FROM 4 AM SUNDAY TO 7 AM CDT MONDAY FOR
MNZ002-003-022>024-027>032-040.
WINTER STORM WARNING FROM 10 AM SUNDAY TO 7 AM CDT MONDAY FOR
MNZ001-004>009-013>017.
&&
$$
UPDATE...ROGERS
SHORT TERM...DK
LONG TERM...MAKOWSKI
AVIATION...JR
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
955 AM CDT SAT APR 13 2013
.UPDATE...
ISSUED AT 955 AM CDT SAT APR 13 2013
1430 UTC WATER VAPOR LOOP SHOWS AN UPPER LOW SPINNING ACROSS LAKE
SUPERIOR AND A MUCH STRONGER VORTICITY MAXIMUM DIGGING ACROSS THE
PACIFIC NORTHWEST. IN-BETWEEN...SHORT WAVE RIDGING ALONG THE
MT/ND BORDER IS EXPECTED TO SLIDE EASTWARD TODAY FOR RELATIVELY
TRANQUIL WEATHER CONDITIONS. SURFACE RIDGE AXIS FROM THE DEVILS
LAKE BASIN DOWN THE JAMES RIVER VALLEY IS ALSO EXPECTED TO MOVE
INTO NORTHWEST MN THIS AFTERNOON AND EVENING...ALLOWING LIGHT AND
VARIABLE WIND TO INCREASE FROM THE EAST ACROSS EASTERN ND THIS
AFTERNOON. THIS SHOULD HELP DISSIPATE ANY REMAINING PATCHY FOG
FROM OVERNIGHT. LATEST RAP SUGGESTS MID-LEVEL CLOUD COVER SHOULD
SLOWLY DISSIPATE THROUGH THE DAY...BUT WITH LATEST IR SATELLITE
SHOWING CONSIDERABLE CLOUDINESS ACROSS MUCH OF THE FORECAST
AREA...WILL INCREASE CLOUD COVER THROUGH MID-AFTERNOON. FOR THOSE
AREAS NOT CURRENTLY SUNNY...EXPECT AT LEAST FILTERED SUNSHINE
ALONG AND EAST OF THE VALLEY BY LATE THIS AFTERNOON. FOR THE FAR
WESTERN FORECAST AREA...LOWERED AFTERNOON HIGHS A FEW DEGREES TO
ACCOUNT FOR CURRENT TEMPERATURES ONLY IN THE TEENS AND OVERCAST
SKIES WHICH WILL LIMIT OVERALL RECOVERY.
WILL NOT MAKE ANY CHANGES FOR NOW TO TONIGHT/TOMORROWS STORM AND
ASSOCIATED HEADLINES AND RE-EVALUATE WITH THIS AFTERNOON/S
FORECAST.
UPDATE ISSUED AT 620 AM CDT SAT APR 13 2013
WE WILL ISSUE A WINTER STORM WARNING FOR THE ENTIRE FORECAST AREA
WITH THIS UPDATE. CONFIDENCE IS HIGH WITH A MAJOR WINTER STORM FROM
LATE TONIGHT THROUGH SUNDAY NIGHT. EXPECT FAIRLY WIDESPREAD SNOW
TOTALS RANGING FROM 6 TO 10 INCHES IN THE NORTHERN 2/3 OF THE
REGION WITH LOWER TOTALS IN THE FAR SOUTH WHERE SOME FREEZING
RAIN/SLEET IS POSSIBLE LATE TONIGHT AND SUNDAY MORNING. SOME AREAS
COULD LOCALLY REACH 1 FOOT MAINLY FROM THE DEVILS LAKE BASING INTO
NORTHEAST ND AND NW ND WHERE THE DEFORMATION SNOW BAND SETS UP.
EXPECT THE MOST SIGNIFICANT IMPACTS LATE TONIGHT IN THE FAR
SOUTH...AND SUNDAY INTO SUNDAY EVENING FURTHER NORTH. WINDS WILL
ALSO INCREASE AND GUST OVER 35 MPH AT TIMES IN THE VALLEY...PRODUCING
CONSIDERABLE BLOWING AND DRIFTING SNOW AND REDUCED VSBYS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 340 AM CDT SAT APR 13 2013
THE MAIN CHALLENGE WILL BE UPCOMING STORM FOR LATE SATURDAY NIGHT
THROUGH SUNDAY NIGHT. MODELS ARE COMING INTO GOOD AGREEMENT
OVERALL...WITH STILL A FEW DETAILS TO IRON OUT.
FOR TODAY...EXPECT SOME LINGERING SNOW SHOWERS/FLURRIES MAINLY IN
THE FAR EAST THIS MORNING. OTHERWISE...SOME CLEARING IS EXPECTED
BY AFTERNOON BUT TEMPS WILL REMAIN WELL BELOW NORMAL.
FOR TONIGHT...EXPECT INCREASING CLOUDS AND PRECIP SHOULD QUICKLY
DEVELOP IN THE SOUTH AROUND OR SHORTLY AFTER 06Z. A DYNAMIC STORM
SYSTEM WILL SPREAD A BAND OF WAA INDUCED SNOW WITH SOME FREEZING
RAIN/SLEET IN THE FAR SOUTH.
ON SUNDAY...A WIDESPREAD BAND OF SNOW...HEAVY AT TIMES...WILL
DEVELOP/SPREAD SLOWLY NORTH AND EAST. THERE COULD STILL BE SOME
RAIN MIXING IN THE FAR SOUTH AND EAST. VERTICAL MOTION FIELDS ARE
STRONG...WITH DEEP LAYERED OMEGA THROUGH 400 MB WITH STRONG FGEN
IN THE MID LEVELS. HIGH MOISTURE VALUES WITH PWATS AROUND 0.75
WILL ALSO ADVECT INTO THE AREA AS 850MB WINDS INCREASE TO AROUND
50 KT. IT WILL ALSO BECOME WINDY IN THE NORTH...AND EXPECT BLOWING
SNOW AND REDUCED VSBYS AS WELL. THE MAIN QUESTION WILL BE HOW MUCH
SNOW ACCUMULATES GIVEN IT IS MID APRIL. THERE SHOULD BE HIGH
ENOUGH QPF RATES TO PRODUCE SNOW RATES OF AN INCH...MAYBE 2...PER
HOUR IN SOME AREAS BY SUNDAY AFTERNOON. TEMPS SHOULD HOVER NEAR
FREEZING FOR MOST AREAS...WITH SOME MELTING POSSIBLE ON PAVEMENT
AND HIGHER ACCUMS ON GRASSY AND SNOW SURFACES. THERE COULD BE
AREAS THAT GET UP TO 6 INCHES ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT APR 13 2013
FOR SUNDAY NIGHT INTO EARLY MONDAY...SFC LOW SHOULD TRACK INTO THE
E/NE FORECAST AREAS WITH WRAPAROUND DEFORMATION SNOW BAND TO THE
NW. THE HEAVIEST SNOW SHOULD FALL FROM THE DVL BASIN INTO NE
ND...WHERE ADDITIONAL AMOUNTS OF UP TO 4 INCHES ARE POSSIBLE.
STORM TOTAL SNOW AMOUNTS BY MONDAY MORNING COULD REACH UP TO A
FOOT IN SOME AREAS...WITH FAVORED LOCATIONS FROM CENTRAL ND INTO
THE DVL BASIN TO AROUND GRAND FORKS TO HALLOCK. FOR NOW WE WILL
CONTINUE WITH THE WINTER STORM WATCH FOR THE ENTIRE REGION SINCE
THE DRY SLOT COULD REDUCE QPF AMOUNTS IN THE SOUTH A BIT. THERE IS
STILL TIME TO IRON OUT DETAILS...WITH THE LARGEST IMPACTS LATE SAT
NIGHT AND SUNDAY. A MAJOR WINTER STORM APPEARS IMMINENT THOUGH FOR
MOST AREAS AT THIS TIME.
QUIETER WEATHER IS ON TAP FOR TUESDAY AS THE UPPER LOW CONTINUES TO
PUSH AWAY. SOUTHWEST FLOW ALOFT WILL OVERSPREAD THE PLAINS AS
SHORTWAVE ENERGY DIVES INTO THE DESERT SOUTHWEST...CARVING OUT A
BROAD LONGWAVE TROUGH OVER THE WESTERN US. UNCERTAINTY STILL REMAINS
HOW THIS SYSTEM WILL EVOLVE ACROSS THE PLAINS. 00Z MODELS GENERALLY
TAKE THE SFC LOW UP INTO THE SOUTHERN GREAT LAKES BY
THURSDAY...KEEPING THE MORE SIGNIFICANT PRECIP TO THE SOUTH AND
EAST. WILL KEEP SOME POPS WITH FOR MID-WEEK GIVEN LOW CONFIDENCE
THOUGH. OTHERWISE...TEMPS WILL CONTINUE TO REMAIN WELL BELOW NORMAL
WITH 850 MB BAROCLINIC DISPLACED WELL SOUTH. EXPECT HIGHS MAINLY IN
THE 30S WITH LOWS IN THE 20S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 955 AM CDT SAT APR 13 2013
PATCHY LOW CIGS AND VIS ALONG THE WESTERN FORECAST AREA WILL
CONTINUE TO IMPROVE FOR THE REST OF THE MORNING. FURTHER
EAST...CEILINGS WILL REMAIN MVFR TO LOW VFR WITH SOME BREAKS
PROVIDING A FEW CLEAR SPOTS AT TIMES. CONDITIONS SHOULD BE VFR AT
ALL TAF SITES BY THIS AFTERNOON AND EARLY EVENING...BUT SHOULD BEGIN
TO DETERIORATE AFTER 06Z TONIGHT AS CLOUDS AND PRECIP BEGIN TO MOVE
INTO THE REGION WITH THE NEXT STORM SYSTEM.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING FROM 4 AM SUNDAY TO 7 AM CDT MONDAY FOR
NDZ028>030-038-039-049-052-053.
WINTER STORM WARNING FROM 10 AM SUNDAY TO 7 AM CDT MONDAY FOR
NDZ006>008-014>016-024-026-027-054.
MN...WINTER STORM WARNING FROM 4 AM SUNDAY TO 7 AM CDT MONDAY FOR
MNZ002-003-022>024-027>032-040.
WINTER STORM WARNING FROM 10 AM SUNDAY TO 7 AM CDT MONDAY FOR
MNZ001-004>009-013>017.
&&
$$
UPDATE...ROGERS
SHORT TERM...DK
LONG TERM...MAKOWSKI
AVIATION...DK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
138 PM EDT SAT APR 13 2013
.SYNOPSIS...
LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL SLOWLY LIFT OUT
TODAY. HIGH PRESSURE FROM THE PLAINS STATES WILL MOVE TO THE OHIO
VALLEY TONIGHT AND THEN MOVE TO THE EAST COAST ON SUNDAY.A COLD
FRONT FROM THE WEST WILL APPROACH THE AREA LATE MONDAY OR TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HRRR AND RUC CONTINUE TO DEVELOP SCT SHRA ACROSS THE CWA BY MIDDAY
AND THIS SEEMS REASONABLE GIVEN THE UPPER TROFFING AND GOOD VORT MAX
THAT WILL ROTATE ACROSS THE AREA. HAVE DECIDED TO ADJUST WX
PARAMETER SO THAT RA/SN MIX WILL GO TO JUST RA FOR ANY TEMPS ABOVE
40 DEGREES AS TEMPS ALOFT JUST NOT COLD ENOUGH FOR SNOW IF BOUNDARY
GETS TOO WARM. WILL CONTINUE ALLOW FOR SOME HOLES IN THE CLOUDS TO
BEGIN TO OCCUR IN THE MID AND LATTER AFTERNOON HOURS...ESPECIALLY
FOR THE SW HALF OF THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL BUILD IN TONIGHT. AREAS THAT CAN CLEAR WILL SEE
CHILLY TEMPERATURES...DOWN AROUND FREEZING. CLOUDS COULD HANG ON
ACROSS EXTREME NE OH/NW PA MUCH OF THE NIGHT...AND HIGH CLOUDS
COULD ARRIVE BEFORE DAYBREAK SO THE FORECAST WILL NOT BE AS COLD
AS IT COULD BE.
LOTS OF RIDGING AT THE SURFACE AND ALOFT ON SUNDAY ALTHOUGH WARM
ADVECTION IS STRONG AND PATCHES OF MID AND HIGH CLOUDS ARE LIKELY.
IT MAY NOT BE SUNNY BUT IT SHOULD TURN OUT AT LEAST PARTLY
SUNNY. TEMPERATURES SHOULD REBOUND TO NEAR NORMAL FROM THE MID 50S
TO AROUND 60.
WILL BE WATCHING THE APPROACH OF THE NEXT COLD FRONT EARLY IN THE
WEEK. THE MODELS CONTINUE TO SUGGEST VARYING ARRIVAL TIMES. THE GFS
REMAINS THE FASTEST MODEL AND SEEMS TO HAVE TOO MUCH MOMENTUM ON
MONDAY ALTHOUGH THE FRONT COULD GET CLOSE TO TOLEDO BY THE END OF
THE DAY. A COMPROMISE OF THE MODELS WOULD SLIDE THE FRONT INTO THE
FORECAST AREA ON TUESDAY BUT LITTLE CONFIDENCE IN THE FORECAST AT
THIS TIME GIVEN THE VARIOUS SOLUTIONS. WILL SLOWLY INCREASE THE
POP MONDAY INTO TUESDAY AND MENTION THUNDER ON TUESDAY. WE SHOULD
GET A WARM DAY ON MONDAY. TUESDAY IS UP FOR GRABS DEPENDING ON THE
SPEED OF THE FRONT AND HOW MUCH CLOUDS AND SHOWERS DEVELOP. THE
FORECAST HIGHS ON TUESDAY WILL BE SOMEWHAT LOWER THAN MONDAY AS A
COMPROMISE BUT THE POTENTIAL TEMPERATURE RANGE IS WIDE ON TUESDAY
DEPENDING ON THE SPEED OF THE FRONTAL PASSAGE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
LOOKING AT A FAMILIAR WX PATTERN FROM MID WEEK ON AS ANOTHER
QUASI-STATIONARY FRONT MOVES INTO OHIO. THE EXACT LOCATION OF THE
FRONT IS DIFFICULT TO DETERMINE AT THIS TIME...AND ITS PLACEMENT
WILL MAKE A SIGNIFICANT DIFFERENCE ON TEMPERATURES AND WEATHER. FOR
NOW WILL CONTINUE THE HIGH CHANCE POPS. BY THURSDAY MOST MODELS
AGREE THAT THE WARM FRONT WILL LIFT NORTH OF THE LAKE AS A STRONGER
LOW MOVES IN FROM THE PLAINS. THE INCREASE IN THE LL JET WILL
SUPPORT WARMER TEMPERATURES DESPITE EXPECTED CLOUD COVER. THIS WILL
LIKELY BE THE BEST CHANCE FOR STRONG CONVECTION. A COLD FRONT WILL
FOLLOW IN THE WAKE OF THE EXITING LOW ON FRIDAY WITH TEMPERATURES
FALLING DURING THE DAY. BY NEXT WEEKEND TEMPERATURES WILL COOL BACK
INTO THE 40S.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AN UPPER LOW OVER EASTERN CANADA WILL MOVE SLOWLY NORTHEAST
TONIGHT. IN THE MEANTIME WEAK IMPULSES IMPEDED IN THIS FLOW WILL
CAUSE SCATTERED LIGHT SHOWERS THROUGH EARLY TONIGHT. SOME OF THE
SHOWERS WILL HAVE MVFR CEILINGS AND VISIBILITIES. HIGH PRESSURE
AT THE SURFACE WILL BE BUILDING IN FROM THE SOUTHWEST TONIGHT AND
THAT SHOULD DECREASE THE CLOUDS. THE HIGH WILL MOVE EAST ON
SUNDAY. A WARM FRONT WILL MOVE ACROSS THE AREA ON SUNDAY CAUSING
MAINLY MID CLOUD AND LIGHT SHOWERS SPRINKLES.
.OUTLOOK...NON VFR AT TIMES LATE MONDAY INTO THURSDAY.
&&
.MARINE...
THE SOUTHWESTERLY FLOW WILL INCREASE TODAY AS AN AREA OF LOW
PRESSURE MOVES OFF TO OUR NORTH AND AN AREA OF HIGH PRESSURE BUILDS
IN FROM THE SOUTHWEST. THE GRADIENT WILL SUPPORT GUSTS OVER 25 KT
THROUGH THE OVERNIGHT WHICH WILL JUSTIFY A SMALL CRAFT ADVISORY. THE
HIGH WILL DOMINATE ON SUNDAY ALLOWING HEADLINES TO FALL OFF. THINGS
TURN AROUND NEXT WEEK AS AN ACTIVE WEATHER PATTERN SETS UP. RAIN AND
PERIODIC SMALL CRAFT WINDS ARE LIKELY FROM TUESDAY ON.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT SUNDAY FOR LEZ146>149.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
LEZ142>145.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KOSARIK
SHORT TERM...KOSARIK
LONG TERM...JAMISON
AVIATION...KIELTYKA
MARINE...JAMISON
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
915 AM EDT SAT APR 13 2013
.SYNOPSIS...
LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL SLOWLY LIFT OUT
TODAY. HIGH PRESSURE FROM THE PLAINS STATES WILL MOVE TO THE OHIO
VALLEY TONIGHT AND THEN MOVE TO THE EAST COAST ON SUNDAY.A COLD
FRONT FROM THE WEST WILL APPROACH THE AREA LATE MONDAY OR TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HRRR AND RUC CONTINUE TO DEVELOP SCT SHRA ACROSS THE CWA BY MIDDAY
AND THIS SEEMS REASONABLE GIVEN THE UPPER TROFFING AND GOOD VORT MAX
THAT WILL ROTATE ACROSS THE AREA. HAVE DECIDED TO ADJUST WX
PARAMETER SO THAT RA/SN MIX WILL GO TO JUST RA FOR ANY TEMPS ABOVE
40 DEGREES AS TEMPS ALOFT JUST NOT COLD ENOUGH FOR SNOW IF BOUNDARY
GETS TOO WARM. WILL CONTINUE ALLOW FOR SOME HOLES IN THE CLOUDS TO
BEGIN TO OCCUR IN THE MID AND LATTER AFTERNOON HOURS...ESPECIALLY
FOR THE SW HALF OF THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL BUILD IN TONIGHT. AREAS THAT CAN CLEAR WILL SEE
CHILLY TEMPERATURES...DOWN AROUND FREEZING. CLOUDS COULD HANG ON
ACROSS EXTREME NE OH/NW PA MUCH OF THE NIGHT...AND HIGH CLOUDS
COULD ARRIVE BEFORE DAYBREAK SO THE FORECAST WILL NOT BE AS COLD
AS IT COULD BE.
LOTS OF RIDGING AT THE SURFACE AND ALOFT ON SUNDAY ALTHOUGH WARM
ADVECTION IS STRONG AND PATCHES OF MID AND HIGH CLOUDS ARE LIKELY.
IT MAY NOT BE SUNNY BUT IT SHOULD TURN OUT AT LEAST PARTLY
SUNNY. TEMPERATURES SHOULD REBOUND TO NEAR NORMAL FROM THE MID 50S
TO AROUND 60.
WILL BE WATCHING THE APPROACH OF THE NEXT COLD FRONT EARLY IN THE
WEEK. THE MODELS CONTINUE TO SUGGEST VARYING ARRIVAL TIMES. THE GFS
REMAINS THE FASTEST MODEL AND SEEMS TO HAVE TOO MUCH MOMENTUM ON
MONDAY ALTHOUGH THE FRONT COULD GET CLOSE TO TOLEDO BY THE END OF
THE DAY. A COMPROMISE OF THE MODELS WOULD SLIDE THE FRONT INTO THE
FORECAST AREA ON TUESDAY BUT LITTLE CONFIDENCE IN THE FORECAST AT
THIS TIME GIVEN THE VARIOUS SOLUTIONS. WILL SLOWLY INCREASE THE
POP MONDAY INTO TUESDAY AND MENTION THUNDER ON TUESDAY. WE SHOULD
GET A WARM DAY ON MONDAY. TUESDAY IS UP FOR GRABS DEPENDING ON THE
SPEED OF THE FRONT AND HOW MUCH CLOUDS AND SHOWERS DEVELOP. THE
FORECAST HIGHS ON TUESDAY WILL BE SOMEWHAT LOWER THAN MONDAY AS A
COMPROMISE BUT THE POTENTIAL TEMPERATURE RANGE IS WIDE ON TUESDAY
DEPENDING ON THE SPEED OF THE FRONTAL PASSAGE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
LOOKING AT A FAMILIAR WX PATTERN FROM MID WEEK ON AS ANOTHER
QUASI-STATIONARY FRONT MOVES INTO OHIO. THE EXACT LOCATION OF THE
FRONT IS DIFFICULT TO DETERMINE AT THIS TIME...AND ITS PLACEMENT
WILL MAKE A SIGNIFICANT DIFFERENCE ON TEMPERATURES AND WEATHER. FOR
NOW WILL CONTINUE THE HIGH CHANCE POPS. BY THURSDAY MOST MODELS
AGREE THAT THE WARM FRONT WILL LIFT NORTH OF THE LAKE AS A STRONGER
LOW MOVES IN FROM THE PLAINS. THE INCREASE IN THE LL JET WILL
SUPPORT WARMER TEMPERATURES DESPITE EXPECTED CLOUD COVER. THIS WILL
LIKELY BE THE BEST CHANCE FOR STRONG CONVECTION. A COLD FRONT WILL
FOLLOW IN THE WAKE OF THE EXITING LOW ON FRIDAY WITH TEMPERATURES
FALLING DURING THE DAY. BY NEXT WEEKEND TEMPERATURES WILL COOL BACK
INTO THE 40S.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
WITH UPPER LOW ALOFT WILL SEE MOSTLY CLOUDY CONDITIONS WITH SPOTTY
RAIN SHOWER THIS AFTERNOON. ANY SHOWER ACTIVITY WILL BE BRIEF WITH
LITTLE RAINFALL OR REDUCED VISIBILITY. THE WINDS WILL PICK UP TO
15G25KT FOR THE BULK OF THE DAY AS AN AREA OF HIGH PRESSURE BUILDS
IN FROM THE SOUTHWEST AND PINCHES THE PRESSURE GRADIENT. WINDS WILL
SETTLE DOWN OVERNIGHT AS THE HIGH SLIDES OVER THE OHIO VALLEY.
.OUTLOOK...NON VFR DEVELOPING TUESDAY AND CONTINUING INTO
WEDNESDAY.
&&
.MARINE...
THE SOUTHWESTERLY FLOW WILL INCREASE TODAY AS AN AREA OF LOW
PRESSURE MOVES OFF TO OUR NORTH AND AN AREA OF HIGH PRESSURE BUILDS
IN FROM THE SOUTHWEST. THE GRADIENT WILL SUPPORT GUSTS OVER 25 KT
THROUGH THE OVERNIGHT WHICH WILL JUSTIFY A SMALL CRAFT ADVISORY. THE
HIGH WILL DOMINATE ON SUNDAY ALLOWING HEADLINES TO FALL OFF. THINGS
TURN AROUND NEXT WEEK AS AN ACTIVE WEATHER PATTERN SETS UP. RAIN AND
PERIODIC SMALL CRAFT WINDS ARE LIKELY FROM TUESDAY ON.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT SUNDAY FOR LEZ146>149.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
LEZ142>145.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KOSARIK/ADAMS
SHORT TERM...KOSARIK
LONG TERM...JAMISON
AVIATION...JAMISON
MARINE...JAMISON
AREA FORECAST DISCUSSION
NWS NORMAN OK
639 PM CDT SUN APR 14 2013
.UPDATE...
MESOSCALE ENVIRONMENT UPDATE...
&&
.DISCUSSION...
A FEW WEAK UPDRAFTS HAVE FINALLY BEEN ABLE TO FIRE ACROSS NORTH
CENTRAL OKLAHOMA WITHIN A REGION OF CU DEVELOPMENT FOCUSED ALONG
THE FRONTAL BOUNDARY. 14/23Z SURFACE ANALYSIS PLACES THE FRONT
FROM SWRN IA SOUTHWEST THROUGH THE TX PANHANDLE. 21Z RAP SOUNDINGS
AT 23Z JUST AHEAD OF THE FRONT REVEAL A FAIRLY DECENT MIXING FROM
THE SURFACE THROUGH APPROXIMATELY 850MB. WITH SKINNY CAPE
PROFILES...MLCAPE VALUES ON RANGE FROM 250 TO 500 J/KG.
HOWEVER...RAP 0-1KM AGL COMPUTED CAPE (LOW LVL CAPE) SHOWS A NICE
POCKET OF 400 TO 550 J/KG NEAR WHERE 50-60 DPTS HAVE POOLED NEAR
THE INTERSECTION OF THE DRY LINE AND COLD FRONT ACROSS N CENTRAL
OK.
UPSTREAM SURFACE ANALYSIS WOULD INDICATE A SHALLOW PROFILE FOR THE
COLD FRONT. AT 14/23Z...TEMPS BEHIND THE FRONT RANGE FROM THE
UPPER 60S/LOWER 70S ACROSS SRN KS...TO THE MID 50S/LOWER 60S
ACROSS SRN NE. THE COMBINATION OF MIXING AT THE SURFACE...MODEST
INSTABILITY AND WEAK LIFT FROM THE FRONT ARE LIKELY REASON THE
CURRENT UPDRAFTS...WHICH DEVELOPED APPROXIMATELY 530ISH...HAVE
CONTINUED TO STRUGGLE.
HOWEVER...RADAR ANALYSIS INDICATES CURRENT CONVECTION MAY BE
DEVELOPING ALONG A PRE-FRONTAL WIND SHIFT/SFC TROUGH...AS A
SECOND BOUNDARY IS DEFINED ON KVNX FROM NEAR CARRIER TO BRAMAN.
BEHIND THIS BOUNDARY...AIR IS A BIT COOLER (LOWER 70S) AND DRIER
(MID 50S DPTS). AS THIS BOUNDARY CATCHES UP WITH THE ONGOING
CONVECTION...IT COULD OFFER SOME ENHANCEMENT.
OVERALL...SEVERE THREAT FOR NORTH CENTRAL OKLAHOMA LOOKS TO BE
DIMINISHING SLIGHTLY FOR THE MOMENT. HOWEVER...IF THE SECONDARY
BOUNDARY OFFERS A BETTER SOURCE OF LIFT...ONE COULD NOT RULE OUT
AT THIS TIME A FEW STRONG TO SEVERE STORMS DEVELOPING. HAIL TO THE
SIZE OF QUARTERS AND WINDS NEAR 60 MPH WOULD BE THE PRIMARY
CONCERNS.
JTK
&&
.PREV DISCUSSION... /ISSUED 238 PM CDT SUN APR 14 2013/
DISCUSSION...
COLD FRONT MOVING THROUGH NORTHWEST OKLAHOMA WILL CONTINUE TO MOVE
SOUTH AND EAST ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT. A
FEW STORMS MAY DEVELOP ALONG THE FRONT LATER TODAY ACROSS MAINLY
NORTH CENTRAL OKLAHOMA. ENOUGH INSTABILITY WILL EXIST FOR THE
POSSIBILITY OF SEVERE WEATHER ASSOCIATED WITH THESE STORMS.
THIS FRONT WILL STALL LATE TONIGHT AND HANG OUT NEAR OR JUST
SOUTH OF THE I-44 CORRIDOR ON MONDAY. WITH NO STRONG FORCING AND
SOME CAPPING ISSUES MUCH OF MONDAY SHOULD REMAIN DRY. THIS FRONT
IS THEN EXPECTED TO TRY AND RETREAT BACK NORTH MONDAY NIGHT AS IT
IS INFLUENCED BY THE STRONGER STORM SYSTEM THAT WILL APPROACH THE
AREA LATER THIS WEEK. AN ISOLATED STORM OR TWO MAY TRY TO DEVELOP
ALONG FRONT OR DRYLINE LATE TUESDAY AFTN INTO THE EVENING HOURS
WITH PERHAPS A BIT BETTER CHANCE TUESDAY NIGHT WITH AID OF
DEVELOPING LLJ.. MAINLY CENTRAL INTO NORTHERN OKLAHOMA.
BY THE TIME WE GET TO WEDNESDAY... SIGNIFICANT DIFFERENCES CONT TO
REMAIN BETWEEN THE MODELS IN LOCATION OF SFC BOUNDARIES. THE
LATEST GFS CONT TO WANT AND TRY TO LIFT THE BOUNDARY WELL NORTH
INTO KANSAS WITH DRYLINE NEAR THE OK/TX BORDER WED AFTN... PUTTING
ALL OF THE AREA IN WARM SECTOR AND A MUCH HIGHER PROBABILITY OF
STRONG/SEVERE STORMS AND HEAVY RAIN ACROSS MUCH OF THE AREA.
HOWEVER... EURO KEEPS BOUNDARY MUCH FARTHER SOUTH AND THIS MAKES
MORE SENSE AS COLDER AIR TO THE NORTH OF THE FRONT WILL BE HARD TO
DISLODGE AND WITH ABUNDANT CLOUD COVER AND PERHAPS ONGOING PRECIP
HAVE A HARD TIME SEEING THIS BOUNDARY MOVE AS FAR NORTH AS GFS
SEEMS TO THINK. WILL THEREFORE CONT TO FOLLOW THE EURO AND KEEP
THE SFC BOUNDARY NEAR OF JUST NORTH OF I-44 CORRIDOR DURING THE
DAY ON WEDNESDAY BEFORE IT SURGES SOUTH LATE WEDNESDAY AND
WEDNESDAY NIGHT.
MUCH COLDER AIRMASS WILL THEN SURGE SOUTH OVERSPREADING THE AREA
WITH A CHANCE TO SEE SOME WINTRY PRECIP... HOWEVER LATEST TRENDS
CONT TO SHOW THIS BEING LESS OF A POSSIBILITY. FOR NOW WILL KEEP A
MENTION OF THIS FOR CONSISTENCY SAKE.
ANOTHER FREEZE MAY THEN OCCUR ACROSS PARTS OF NORTHERN OKLAHOMA
THURSDAY MORNING AND THEN AGAIN FRIDAY MORNING. FREEZING TEMPS
COULD GET NEAR CENTRAL AND INTO SOUTHWEST OKLAHOMA FRIDAY MORNING.
ANOTHER WEAKER FRONT WILL APPROACH NEXT WEEKEND... KEEPING TEMPS
BELOW NORMAL THROUGH REMAINDER OF EXTENDED.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 54 73 55 73 / 10 10 10 10
HOBART OK 48 72 52 74 / 10 10 10 10
WICHITA FALLS TX 55 83 61 87 / 10 10 10 10
GAGE OK 44 66 43 64 / 10 0 10 10
PONCA CITY OK 50 65 46 63 / 40 10 20 10
DURANT OK 64 84 65 83 / 0 10 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR OKZ033-036.
TX...RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR TXZ083>085-087-
088.
&&
$$
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
401 PM CDT SAT APR 13 2013
.SHORT-TERM (TONIGHT THROUGH SUNDAY NIGHT)...DESPITE A POTENT UPPER
LEVEL LOW CURRENTLY MVG ACROSS W TX WITH ENERGY ALOFT EXPECTED TO MV
ACROSS S TX TONIGHT...CONFIDENCE IS LOW THAT THE CWA WILL SEE ANY
BENIFICIAL RAIN. THE NAM AND RUC13 SHOW VERY LIGHT PRECIP ACROSS THE
NE CWA AND OVER THE WATERS BY EARLY SUNDAY MORNING. MODELS PROG THE
DEEPER MOISTURE TO BE ALONG THE RIO GRANDE AND EXTREME ERN CWA...BUT
MOISTURE IS VERY LIMITED. CIN VALUES ARE PROGD TO BE VERY HIGH ALONG
WITH LOW CAPE VALUES. MOS GUIDANCE POPS ARE ALL LESS THAN 20 PERCENT
WITH SOME LOCATIONS IN THE SINGLE DIGITS. ALL THE MODELS SHOW SOME
PRECIP EITHER N...S...E OR W OF THE CWA TONIGHT...AND WITH THE UPPER
SYSTEM PROGD TO MOVE ACROSS THE REGION TONIGHT...DID NOT WANT TO
COMPLETELY REMOVE POPS OR MENTION OF PRECIP. LOWERED 20 POPS TO 10
ACROSS THE LAND AREAS AND REMOVED TSRA`S FOR MOST OF THE AREA EXCEPT
THE FAR W WHERE STORMS OFF THE SIERRA MADRE COULD MOVE FAR ENOUGH E
TO REACH THE WRN CWA. RAIN CHCS DECREASE FROM W TO E THROUGH SUNDAY
MORNING AS THE UPPER LOW TRACKS E. PRESSURE GRADIENT ACROSS S TX
WILL RELAX THRU SUNDAY AS THE LOW PRESSURE SYSTEM EXITS THE REGION.
AIRMASS ABV THE SFC WILL BE DRIER ON SUNDAY LEADING TO WARMER TEMPS.
FAIRLY LIGHT WINDS...EXCEPT STRONGER ALONG THE RIO GRANDE...AND A
SHALLOW MOIST LAYER AT THE SFC COULD LEAD TO FOG SUNDAY NIGHT ACROSS
THE EASTERN CWA. FCST SOUNDINGS LOOK CONDUCIVE FOR RADIATIONAL FOG
DVLPMNT...POSSIBLY DENSE. SEA FOG COULD ALSO ADVECT INLAND SUNDAY
NIGHT DUE TO HIGHER DEWPOINTS OVER RELATIVELY COOLER SST.
&&
.MARINE...WEAK TO MODERATE EASTERLY FLOW WILL RELAX OVERNIGHT AND
VEER TO THE SE IN RESPONSE TO A LOW PRESSURE SYSTEM MOVE ACROSS THE
REGION AND EXITING TO THE E. ONSHORE FLOW WILL STRENGTHEN SLIGHTLY
SUNDAY NIGHT IN RESPONSE TO ANOTHER LOW PRESSURE SYSTEM DIGGING SWD
ALONG THE WEST COAST. PATCHY SEA FOG WILL BE POSSIBLE SUNDAY NIGHT
DUE TO DEWPOINTS IN THE UPPER 60S TO NEAR 70 MOVING ACROSS
RELATIVELY COOLER SST.
&&
.LONG TERM (MONDAY THROUGH SATURDAY NIGHT)...START OF PERIOD BEGINS
WITH ONSHORE FLOW AT THE SURFACE AND MOSTLY ZONAL FLOW ALOFT. MODELS
DEVELOP A DEEP UPPER LEVEL TROUGH/DISTURBANCE OVER THE ROCKIES THAT
WILL MOVE ACROSS THE CENTRAL CONUS AND REGION WEDNESDAY AND
THURSDAY. AHEAD OF THIS DISTURBANCE AND ASSOCIATED COLD FRONT EXPECT
ONSHORE FLOW TO INCREASE...AND SCEC TO SCA CONDITION TO DEVELOP
TUESDAY AFTERNOON THROUGH THURSDAY. PWAT VALUES INCREASE AHEAD OF
APPROACHING DISTURBANCE/SURFACE COLD FRONT TO 1.3 UP TO 1.5.
ANTICIPATE ISOLATED TO SHOWERS AND TSTMS AHEAD COLD FRONT ON
WEDNESDAY NIGHT/THURSDAY MORNING. TIMING DIFFERENCES WITH FROPA
STILL EXIST...WITH THE GFS A LITTLE SLOWER THAN THE ECMWF. EVEN
SO...EXPECT FRONT TO BE MOVING OFFSHORE AOA 18Z THURSDAY...AND
TEMPERATURES TO FALL THROUGH THE AFTERNOON. BEHIND THE FRONT WILL SEE
STRONG WINDS...ESPECIALLY OFFSHORE...AND SCA WILL DEVELOP ACROSS THE
GULF WATERS THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 65 85 69 84 70 / 10 10 10 10 10
VICTORIA 59 83 67 84 69 / 10 10 10 10 10
LAREDO 67 94 71 98 73 / 10 0 10 10 10
ALICE 64 88 68 90 69 / 10 10 10 10 10
ROCKPORT 66 78 69 76 69 / 10 10 10 10 10
COTULLA 62 91 67 96 69 / 10 0 10 10 10
KINGSVILLE 65 88 69 87 70 / 10 10 10 10 10
NAVY CORPUS 68 78 70 77 71 / 10 10 10 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TE/81...SHORT TERM
LK/84...LONG TERM
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1217 PM CDT SAT APR 13 2013
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...LOW LEVEL STRATOCU DEVELOPING ACROSS NORTHERN MEXICO
AND DEEP SOUTH TEXAS AND THIS TREND WILL CONTINUE FOR THE NEXT 24
HOURS. CIG HEIGHTS ARE MAINLY VFR ACROSS THE AREA WITH
INTERMITTENT MVFR ACROSS NORTHERN MEXICO. BASED ON POINT SOUNDINGS
AND MIXING...CIGS WILL STAY VFR THROUGH THE EARLY EVENING. THIS
CLOUD DECK WILL LOWER INTO THE MVFR RANGE LATER THIS EVENING INTO
SUNDAY MORNING AS TEMPERATURES COOL. THERE IS AN OUTSIDE SHOT FOR
SHOWERS OVERNIGHT AS A MID LEVEL DISTURBANCE CROSS OVER THE AREA
BUT CONFIDENCE IS TOO LOW TO PLACE IN TAFS. WINDS WILL CONTINUE TO
BE GUSTY THIS AFTERNOON WITH SPEEDS DECREASING AFTER SUNSET.
&&
.PREV DISCUSSION... /ISSUED 623 AM CDT SAT APR 13 2013/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
MOSTLY MID TO HIGH LEVEL CLOUDS ACROSS THE CWA THIS MORNING.
CEILINGS WERE NEAR 300FT AT KHBV TO NEAR 2100FT AT KAPY. MVFR
CONDITIONS ARE A LOW PROBABILITY EARLY THIS MORNING WITH VFR
AFTER 15Z AS MIXING INCREASES. MVFR CEILINGS WILL LIKELY RETURN TONIGHT AS
LOW LEVEL MOISTURE INCREASES AHEAD OF A 500MB SHORTWAVE TROUGH
APPROACHING FROM THE WEST. ISOLATED SHOWERS MAY DEVELOP ACROSS THE
RIO GRANDE VALLEY TONIGHT WITH PATCHY FOG.
PREV DISCUSSION... /ISSUED 403 AM CDT SAT APR 13 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...500MB LOW/TROUGH ACROSS
NORTHWEST MEXICO THIS MORNING WILL MOVE EASTWARD ACROSS NORTHERN
MEXICO THIS AFTERNOON AND EASTWARD ACROSS EAST TEXAS SUNDAY. AN
UPPER LEVEL JET ACROSS NORTHERN MEXICO WILL MOVE EASTWARD ACROSS
THE CWA THIS AFTERNOON INTO TONIGHT PROVIDING ENOUGH FORCING WITH
THE SHORTWAVE TROUGH TO PROVIDE A SLIGHT CHANCE OF CONVECTION
ACROSS THE AREA TONIGHT INTO EARLY SUNDAY BEFORE DRIER AIR AND
SUBSIDENCE INCREASES FROM THE WEST ON SUNDAY. RUC13 CONTINUES TO
INDICATE 850MB RELATIVE HUMIDITY INCREASING ACROSS THE RIO GRANDE
VALLEY TODAY AND THIS LIMIT DIURNAL HEATING TO AN EXTENT THIS
AFTERNOON. CLOUD COVER WILL INCREASE THIS AFTERNOON AND CONTINUE
TO INCREASE TONIGHT BEFORE CLEARING FROM WEST TO EAST SUNDAY.
TEMPERATURES WILL BE WARMER SUNDAY THAN TODAY WITH WINDS VEERING
TO THE SOUTH AND THE LACK OF CLOUDS...ESPECIALLY OUT WEST.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...WEAK RIDGING WILL BE
BUILDING AT THE BEGINNING OF NEXT WEEK AS THE LATEST IMPULSE RACES
OFF TO THE EAST. DRIER LOWER LEVELS AND DRY SW FLOW ALOFT WILL
PRECLUDE PRECIPITATION THROUGH WEDNESDAY...WITH TEMPERATURES
GRADUALLY CLIMBING INTO THE MID TO UPPER 90S. THE NEXT LARGE-SCALE
WEATHER SYSTEM DIVES ACROSS THE ROCKIES AND INTO TEXAS WEDNESDAY
EVENING. THIS WILL DRIVE THE NEXT COLD FRONT THROUGH TEXAS
WEDNESDAY NIGHT. MODELS ARE STILL A BIT DIFFERENT ON LOCATING THE
CENTRAL SFC LOW ALONG THE ADVANCING FRONT...BUT ARE SIMILAR IN THE
FINAL TIMING OF THE FRONT. IT IS EXPECTED TO ARRIVE THURSDAY
MORNING...WITH SHOWER AND THUNDERSTORM ACTIVITY. THE FRONT WILL
MOVE THROUGH QUICKLY...WITH ONLY SOME RESIDUAL RAIN CHANCES
POSSIBLE FOR THE IMMEDIATE COASTAL AREAS THURSDAY AFTERNOON. DRIER
AIR WILL MOVE IN QUICKLY IN THE WAKE OF THE FRONT...WITH HIGH
THURSDAY ONLY EXPECTED TO REACH THE UPPER 70S TO LOWER 80S.
MARINE...
TODAY THROUGH SUNDAY...SEAS WERE NEAR 4 FEET WITH SOUTHEAST WINDS
NEAR 14 KNOTS AT BUOY020 EARLY THIS MORNING. MODERATE EAST TO
SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL WATERS TODAY
BEFORE THE PRESSURE GRADIENT WEAKENS ACROSS THE WESTERN GULF OF
MEXICO TONIGHT. LIGHT EAST TO SOUTHEAST WINDS WILL PREVAIL TONIGHT
INTO SUNDAY AS HIGH PRESSURE ACROSS THE SOUTHEAST UNITED STATES
MOVES EASTWARD AND A FRONTAL SYSTEM MOVES INTO THE NORTH CENTRAL
U.S.
MONDAY THROUGH THURSDAY...SOUTHEAST WINDS WILL INCREASE STARTING
MONDAY AS THE SFC HIGH MOVES INTO THE SOUTHEASTERN US AND LOW
PRESSURE DRIFTS INTO THE TEXAS PANHANDLE. GRADIENT REMAINS
TIGHT...SO WINDS OF AT LEAST 15 KNOTS WILL CONTINUE THROUGH
WEDNESDAY. BREEZY CONDITIONS WILL LEAD TO GRADUALLY INCREASING
SEAS...REACHING 5 TO 6 FEET WEDNESDAY. THE NEXT FRONT IS EXPECTED
THURSDAY MORNING...SWITCHING WINDS TO THE NORTH AND INCREASING TO
20 TO 25 KNOTS...WITH SEAS REACHING 8 TO 10 FEET.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
55/60
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
623 AM CDT SAT APR 13 2013
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
MOSTLY MID TO HIGH LEVEL CLOUDS ACROSS THE CWA THIS MORNING.
CEILINGS WERE NEAR 300FT AT KHBV TO NEAR 2100FT AT KAPY. MVFR
CONDITIONS ARE A LOW PROBABILITY EARLY THIS MORNING WITH VFR
AFTER 15Z AS MIXING INCREASES. MVFR CEILINGS WILL LIKELY RETURN TONIGHT AS
LOW LEVEL MOISTURE INCREASES AHEAD OF A 500MB SHORTWAVE TROUGH
APPROACHING FROM THE WEST. ISOLATED SHOWERS MAY DEVELOP ACROSS THE
RIO GRANDE VALLEY TONIGHT WITH PATCHY FOG.
&&
.PREV DISCUSSION... /ISSUED 403 AM CDT SAT APR 13 2013/
SHORT TERM /TODAY THROUGH SUNDAY/...500MB LOW/TROUGH ACROSS
NORTHWEST MEXICO THIS MORNING WILL MOVE EASTWARD ACROSS NORTHERN
MEXICO THIS AFTERNOON AND EASTWARD ACROSS EAST TEXAS SUNDAY. AN
UPPER LEVEL JET ACROSS NORTHERN MEXICO WILL MOVE EASTWARD ACROSS
THE CWA THIS AFTERNOON INTO TONIGHT PROVIDING ENOUGH FORCING WITH
THE SHORTWAVE TROUGH TO PROVIDE A SLIGHT CHANCE OF CONVECTION
ACROSS THE AREA TONIGHT INTO EARLY SUNDAY BEFORE DRIER AIR AND
SUBSIDENCE INCREASES FROM THE WEST ON SUNDAY. RUC13 CONTINUES TO
INDICATE 850MB RELATIVE HUMIDITY INCREASING ACROSS THE RIO GRANDE
VALLEY TODAY AND THIS LIMIT DIURNAL HEATING TO AN EXTENT THIS
AFTERNOON. CLOUD COVER WILL INCREASE THIS AFTERNOON AND CONTINUE
TO INCREASE TONIGHT BEFORE CLEARING FROM WEST TO EAST SUNDAY.
TEMPERATURES WILL BE WARMER SUNDAY THAN TODAY WITH WINDS VEERING
TO THE SOUTH AND THE LACK OF CLOUDS...ESPECIALLY OUT WEST.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...WEAK RIDGING WILL BE
BUILDING AT THE BEGINNING OF NEXT WEEK AS THE LATEST IMPULSE RACES
OFF TO THE EAST. DRIER LOWER LEVELS AND DRY SW FLOW ALOFT WILL
PRECLUDE PRECIPITATION THROUGH WEDNESDAY...WITH TEMPERATURES
GRADUALLY CLIMBING INTO THE MID TO UPPER 90S. THE NEXT LARGE-SCALE
WEATHER SYSTEM DIVES ACROSS THE ROCKIES AND INTO TEXAS WEDNESDAY
EVENING. THIS WILL DRIVE THE NEXT COLD FRONT THROUGH TEXAS
WEDNESDAY NIGHT. MODELS ARE STILL A BIT DIFFERENT ON LOCATING THE
CENTRAL SFC LOW ALONG THE ADVANCING FRONT...BUT ARE SIMILAR IN THE
FINAL TIMING OF THE FRONT. IT IS EXPECTED TO ARRIVE THURSDAY
MORNING...WITH SHOWER AND THUNDERSTORM ACTIVITY. THE FRONT WILL
MOVE THROUGH QUICKLY...WITH ONLY SOME RESIDUAL RAIN CHANCES
POSSIBLE FOR THE IMMEDIATE COASTAL AREAS THURSDAY AFTERNOON. DRIER
AIR WILL MOVE IN QUICKLY IN THE WAKE OF THE FRONT...WITH HIGH
THURSDAY ONLY EXPECTED TO REACH THE UPPER 70S TO LOWER 80S.
MARINE...
TODAY THROUGH SUNDAY...SEAS WERE NEAR 4 FEET WITH SOUTHEAST WINDS
NEAR 14 KNOTS AT BUOY020 EARLY THIS MORNING. MODERATE EAST TO
SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL WATERS TODAY
BEFORE THE PRESSURE GRADIENT WEAKENS ACROSS THE WESTERN GULF OF
MEXICO TONIGHT. LIGHT EAST TO SOUTHEAST WINDS WILL PREVAIL TONIGHT
INTO SUNDAY AS HIGH PRESSURE ACROSS THE SOUTHEAST UNITED STATES
MOVES EASTWARD AND A FRONTAL SYSTEM MOVES INTO THE NORTH CENTRAL
U.S.
MONDAY THROUGH THURSDAY...SOUTHEAST WINDS WILL INCREASE STARTING
MONDAY AS THE SFC HIGH MOVES INTO THE SOUTHEASTERN US AND LOW
PRESSURE DRIFTS INTO THE TEXAS PANHANDLE. GRADIENT REMAINS
TIGHT...SO WINDS OF AT LEAST 15 KNOTS WILL CONTINUE THROUGH
WEDNESDAY. BREEZY CONDITIONS WILL LEAD TO GRADUALLY INCREASING
SEAS...REACHING 5 TO 6 FEET WEDNESDAY. THE NEXT FRONT IS EXPECTED
THURSDAY MORNING...SWITCHING WINDS TO THE NORTH AND INCREASING TO
20 TO 25 KNOTS...WITH SEAS REACHING 8 TO 10 FEET.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
61
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
403 AM CDT SAT APR 13 2013
.SHORT TERM /TODAY THROUGH SUNDAY/...500MB LOW/TROUGH ACROSS
NORTHWEST MEXICO THIS MORNING WILL MOVE EASTWARD ACROSS NORTHERN
MEXICO THIS AFTERNOON AND EASTWARD ACROSS EAST TEXAS SUNDAY. AN
UPPER LEVEL JET ACROSS NORTHERN MEXICO WILL MOVE EASTWARD ACROSS
THE CWA THIS AFTERNOON INTO TONIGHT PROVIDING ENOUGH FORCING WITH
THE SHORTWAVE TROUGH TO PROVIDE A SLIGHT CHANCE OF CONVECTION
ACROSS THE AREA TONIGHT INTO EARLY SUNDAY BEFORE DRIER AIR AND
SUBSIDENCE INCREASES FROM THE WEST ON SUNDAY. RUC13 CONTINUES TO
INDICATE 850MB RELATIVE HUMIDITY INCREASING ACROSS THE RIO GRANDE
VALLEY TODAY AND THIS LIMIT DIURNAL HEATING TO AN EXTENT THIS
AFTERNOON. CLOUD COVER WILL INCREASE THIS AFTERNOON AND CONTINUE
TO INCREASE TONIGHT BEFORE CLEARING FROM WEST TO EAST SUNDAY.
TEMPERATURES WILL BE WARMER SUNDAY THAN TODAY WITH WINDS VEERING
TO THE SOUTH AND THE LACK OF CLOUDS...ESPECIALLY OUT WEST.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...WEAK RIDGING WILL BE
BUILDING AT THE BEGINNING OF NEXT WEEK AS THE LATEST IMPULSE RACES
OFF TO THE EAST. DRIER LOWER LEVELS AND DRY SW FLOW ALOFT WILL
PRECLUDE PRECIPITATION THROUGH WEDNESDAY...WITH TEMPERATURES
GRADUALLY CLIMBING INTO THE MID TO UPPER 90S. THE NEXT LARGE-SCALE
WEATHER SYSTEM DIVES ACROSS THE ROCKIES AND INTO TEXAS WEDNESDAY
EVENING. THIS WILL DRIVE THE NEXT COLD FRONT THROUGH TEXAS
WEDNESDAY NIGHT. MODELS ARE STILL A BIT DIFFERENT ON LOCATING THE
CENTRAL SFC LOW ALONG THE ADVANCING FRONT...BUT ARE SIMILAR IN THE
FINAL TIMING OF THE FRONT. IT IS EXPECTED TO ARRIVE THURSDAY
MORNING...WITH SHOWER AND THUNDERSTORM ACTIVITY. THE FRONT WILL
MOVE THROUGH QUICKLY...WITH ONLY SOME RESIDUAL RAIN CHANCES
POSSIBLE FOR THE IMMEDIATE COASTAL AREAS THURSDAY AFTERNOON. DRIER
AIR WILL MOVE IN QUICKLY IN THE WAKE OF THE FRONT...WITH HIGH
THURSDAY ONLY EXPECTED TO REACH THE UPPER 70S TO LOWER 80S.
&&
.MARINE...
TODAY THROUGH SUNDAY...SEAS WERE NEAR 4 FEET WITH SOUTHEAST WINDS
NEAR 14 KNOTS AT BUOY020 EARLY THIS MORNING. MODERATE EAST TO
SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL WATERS TODAY
BEFORE THE PRESSURE GRADIENT WEAKENS ACROSS THE WESTERN GULF OF
MEXICO TONIGHT. LIGHT EAST TO SOUTHEAST WINDS WILL PREVAIL TONIGHT
INTO SUNDAY AS HIGH PRESSURE ACROSS THE SOUTHEAST UNITED STATES
MOVES EASTWARD AND A FRONTAL SYSTEM MOVES INTO THE NORTH CENTRAL
U.S.
MONDAY THROUGH THURSDAY...SOUTHEAST WINDS WILL INCREASE STARTING
MONDAY AS THE SFC HIGH MOVES INTO THE SOUTHEASTERN US AND LOW
PRESSURE DRIFTS INTO THE TEXAS PANHANDLE. GRADIENT REMAINS
TIGHT...SO WINDS OF AT LEAST 15 KNOTS WILL CONTINUE THROUGH
WEDNESDAY. BREEZY CONDITIONS WILL LEAD TO GRADUALLY INCREASING
SEAS...REACHING 5 TO 6 FEET WEDNESDAY. THE NEXT FRONT IS EXPECTED
THURSDAY MORNING...SWITCHING WINDS TO THE NORTH AND INCREASING TO
20 TO 25 KNOTS...WITH SEAS REACHING 8 TO 10 FEET.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 80 68 83 70 / 10 20 10 10
BROWNSVILLE 81 68 85 70 / 10 20 10 10
HARLINGEN 84 67 88 69 / 10 20 10 10
MCALLEN 85 69 91 70 / 10 20 10 10
RIO GRANDE CITY 86 67 94 70 / 10 20 10 10
SOUTH PADRE ISLAND 76 68 77 70 / 10 20 10 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WWW.WEATHER.GOV/BROWNSVILLE
61/64
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
825 PM CDT SUN APR 14 2013
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 813 PM CDT SUN APR 14 2013
MAIN AREA OF PCPN WAS OCCURRING ACROSS NC WI EARLY THIS EVG...WITH
DRY CONDITIONS FARTHER SE...INCLUDING THE FOX VALLEY AND LKSHR AREAS.
WARM AIR ALOFT HAD CHANGED THE SNOW TO FREEZING RAIN OVER NC WI...
WHERE SFC TEMPS WERE STILL AT OR SLIGHTLY BLO FREEZING. SFC WET BULB
TEMPS REMAINED BLO FREEZING OVER NC/FAR NE WI...AND MODEL FCSTS SHOW
THIS CONTINUING OVER FAR NORTHERN WI UNTIL AT LEAST 06Z. GIVEN THIS...
PLUS SEVERAL REPORTS OF ICING AND ONE REPORT OF CARS IN DITCHES...
HAVE OPTED TO ISSUE A FREEZING RAIN ADVISORY FOR THE NEXT 5 HOURS
OR SO.
RAIN WILL FILL IN ACROSS THE SE HALF OF THE CWA LATE THIS EVG AND
EARLY MONDAY MORNING...AS THE OCCLUDED FRONT MOVES THROUGH. ONCE
THE FRONT PASSES THROUGH...PCPN SHOULD DECREASE RAPIDLY. ALTHOUGH
TSTMS OVER N IA HAVE DISSIPATED...DECIDED TO KEEP A CHANCE OF THUNDER
IN C/EC WI DURING THE LATE EVG/EARLY MONDAY MORNING PERIOD...AS BEST
LI`S DROP TO ZERO TO -1 C.
HOURLY POP/WX GRIDS HAVE BEEN UPDATED TO MATCH EXPECTED TRENDS FOR
THE REST OF THE NIGHT.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ELONGATED LOW
PRESSURE SPINNING ALONG THE IOWA/NEBRASKA BORDER THIS
AFTERNOON...AND A SURFACE WARM FRONT EXTENDING EASTWARD ACROSS
NORTHERN ILLINOIS. SOUTH OF THE WARM FRONT...TEMPERATURES ARE IN
THE 60S AND 70S. BUT NORTH OF THE FRONT...A 50KT SSW LLJ IS LEADING TO
A BAND OF PRECIPITATION WHICH IS NOW PUSHING INTO THE NORTHERN
SECTIONS OF THE BADGER STATE. TEMPERATURES REMAIN IN THE 20S AND
30S WITHIN THIS BAND OF PRECIP...WHERE LOCATIONS OVER CENTRAL
WISCONSIN HAVE PICKED UP A QUICK 2-3 INCHES OF WET SNOW. A FEW
SPOTTER REPORTS HAVE CONFIRMED WHAT DUAL POL IS SHOWING...THAT SNOW
IS MIXING WITH RAIN AND SLEET...WITH THE CHANGE OVER NOW SPREADING
INTO SOUTHERN MARATHON AND SHAWANO COUNTIES. ADDITIONALLY...SURFACE
WET BULB ZERO TEMPS ARE SPREADING NORTHEAST INTO EAST-CENTRAL
WISCONSIN...SO SHOULDNT SEE TOO MUCH MORE ACCUMS IN THESE AREAS.
STILL EXPECTING THE MODERATE TO HEAVY SNOW TO SPREAD INTO
NORTH-CENTRAL WISCONSIN THIS AFTERNOON WHERE A QUICK 3 INCHES WILL
LIKELY FALL. WILL CONTINUE TO HANDLE THE SNOWFALL WITH SPS
UPDATES. PRECIP CONTINUES TO BE THE MAIN FORECAST CONCERN FOR THIS
FORECAST.
TONIGHT...LOW PRESSURE WILL OCCLUDE AS IT LIFTS NORTH OVER SOUTHERN
MINNESOTA...WHILE THE OCCLUDED/COLD FRONT WILL SWEEP ACROSS THE AREA
LATE THIS EVENING AND THROUGH THE OVERNIGHT HOURS. SNOW/SLEET LOOK
TO BE ONGOING OVER NORTH-CENTRAL WISCONSIN AT THE START OF THE
EVENING WHILE CONDITIONS LOOK TO BE DRY FOR A PERIOD OVER
EAST-CENTRAL AND POSSIBLY FAR NORTHEAST WISCONSIN. THIS DRY PERIOD
OVER THE EAST WILL BE SHORT-LIVED HOWEVER...AS A BAND OF SHOWERS AND
EMBEDDED THUNDERSTORMS WILL MOVE THROUGH ALONG THE OCCLUDED/COLD
FRONT. PROGGED SOUNDINGS INDICATE THAT PTYPE SHOULD BE MAINLY RAIN
ACROSS THE REGION BY THE TIME THIS BAND ARRIVES...WHICH WILL LOOK TO
DUMP AROUND 0.75 INCHES OF RAIN OVER WESTERN SECTIONS OF THE CWA.
AMOUNTS SHOULD DROP OFF TO THE EAST AS INSTABILITY IS LOST THROUGH
THE NIGHT. BEST CHANCES OF THUNDER LOOK TO OCCUR OVER CENTRAL AND
EAST-CENTRAL AND WILL KEEP IT IN THE FORECAST. TEMPERATURES WILL
LIKELY PEAK LATE IN THE EVENING OR EARLY OVERNIGHT...JUST AHEAD OF
THE FRONT. LOWS IN THE 30S AND 40S.
MONDAY...OCCLUDED LOW PRESSURE WILL LIFT NE ACROSS NORTHERN
MINNESOTA. PRECIP WILL HAVE EXITED ALONG THE FRONT BY THE START OF
THE PERIOD AND SKIES WILL LIKELY TURN MOSTLY CLEAR FOR A PERIOD
DURING THE MORNING. HOWEVER...AS COLDER AIR FILTERS IN FROM THE
WEST AND MID-LEVEL TEMPS COOL...STEEPENING LOW LEVEL LAPSE RATES AND
WRAP AROUND MOISTURE WILL LEAD TO INCREASING CLOUDS FROM LATE
MORNING THROUGH THE REST OF THE DAY. COULD SEE A FEW INSTABILITY
RAIN AND SNOW SHOWERS DEVELOP OVER CENTRAL AND NORTHEAST WISCONSIN
IN THE AFTERNOON. GUSTY SOUTHWEST WINDS WILL BRING IN THE WARMEST
TEMPS THE AREA HAS SEEN IN SOME TIME...AND WILL GO WITH HIGHS
RANGING FROM THE LOW 40S NORTH TO THE MID 50S NEAR LAKE MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
FLOOD POTENTIAL IS PROBABLY THE MAIN CHALLENGE FOR THIS FORECAST
PERIOD. THE COLD FRONT MOVES THROUGH MONDAY WITH DRY BUT
SEASONABLE AIR FOLLOWING FOR MONDAY NIGHT THROUGH TUESDAY NIGHT.
SNOW WILL PROBABLY BE GONE OVER MUCH OF THE AREA BELOW 1000 FT
ELEVATION BY THEN WITH THAT SNOW MELT PROBABLY CONTRIBUTING TO
RISES OF THE WOLF RIVER AND SMALL STREAMS OVER EAST CENTRAL
WISCONSIN. MODELS ARE NOW IN GENERAL AGREEMENT WITH SURFACE LOW THAT
MOVES NORTHEAST FROM SOUTHERN PLAINS TO LOWER MICHIGAN WEDNESDAY
THROUGH THURSDAY. LOOKS LIKE THIS WILL BE A LARGELY RAIN EVENT
UNLESS THE STORM TRACKS FURTHER SOUTH. A RAIN EVENT COUPLED BY
SNOW MELT IN THE NORTH WILL LIKELY CAUSE SOME FLOODING OF SMALL
STREAMS AROUND THE AREA BY THURSDAY BUT SIGNIFICANTLY COLDER AND
DRIER AIR WILL SLOW SNOW MELT FRIDAY AND SATURDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 634 PM CDT SUN APR 14 2013
MAIN AVIATION CONCERNS ARE FREEZING RAIN OVER NC WI EARLY THIS EVG...
THE POTENTIAL FOR TSTMS ACROSS MAINLY C/EC WI MID-EVENING TO VERY
EARLY MONDAY MORNING...AND LLWS. WIDESPREAD MVFR/IFR CONDITIONS
ARE ANTICIPATED TONIGHT...WITH MVFR CONDITIONS IMPROVING TO VFR
ON MONDAY.
WARM AIR ALOFT WAS SURGING NORTHWARD EARLY THIS EVG...CAUSING SNOW
OVER FAR NORTHERN WI TO CHANGE TO SLEET AND FREEZING RAIN. SURFACE
TEMPS WERE STILL IN THE UPPER 20S/LOWER 30S OVER NC WI...MAINLY
NORTH OF CWA/AUW. EXPECT SEVERAL MORE HOURS OF FZRA OVER FAR N WI...
BUT CWA/AUW SHOULD CHANGE TO RAIN BY AROUND 01Z...AND RHI BY AROUND
03Z.
WIDESPREAD LIGHT TO MODERATE RAIN WILL SPREAD BACK ACROSS THE REST
OF THE FCST AREA LATER THIS EVG AND OVERNIGHT...AS A SFC LOW AND
ASSOCIATED OCCLUDED FRONT MOVE THROUGH. A SMALL AREA OF TSTMS HAS
DEVELOPED OVER NORTHERN IA...AND MAY AFFECT AT LEAST THE CWA/AUW
TAF SITES BETWEEN 03Z-05Z. BACKED OFF ON THE PREVAILING THUNDER
AT THOSE TAFS SITES...BUT KEPT A TEMPO GROUP FOR TSTMS. WILL
JUST WATCH THE OTHER TAF SITS FOR POSSIBLE INCLUSION OF THUNDER
AS THE EVG PROGRESSES.
LLWS WILL CONTINUE ACROSS THE REGION UNTIL THE OCCLUDED FRONT
MOVES THROUGH OVERNIGHT. THE LLWS SHOULD WANE AT THE TAF SITES
FROM WEST TO EAST BETWEEN 07Z-09Z. THE PCPN IS ALSO EXPECTED TO
END AFTER THE FRONT MOVES THROUGH.
STRONG SW WINDS ARE EXPECTED TO DEVELOP BY AROUND MIDDAY MONDAY...
WITH GUSTS TO 30-35 KTS LIKELY.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN APR 14 2013
CONTINUED CONCERNS FOR FLOODING ISSUES GIVEN EXPECTED
QPF WITH THE FRONTAL PASSAGE TONIGHT. AN ADDITIONAL THREE QUARTERS
TO AN INCH OF PRECIP MAY FALL OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN BY MONDAY MORNING. WARMER TEMPERATURES TONIGHT AND MONDAY
WILL ADD SNOW MELT INTO THE EQUATIONS. CONCERNS ADDRESSED IN CURRENT
ESF PRODUCT AND RIVER FLOOD STATEMENTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ005-010>012-
018-019.
&&
$$
UPDATE.........KIECKBUSCH
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
712 PM CDT SUN APR 14 2013
.SHORT TERM...
712 PM CDT SUN APR 14 2013
WARM FRONT IS MAKING NORTHWARD PROGRESS ACROSS THE SOUTHERN
PORTIONS OF THE FORECAST AREA EARLY THIS EVENING. TEMPERATURES
WARMED INTO THE LOWER 40S AS FAR NORTH AS KAUM-KFKA-KY51-KDLL
THROUGH 00Z. READINGS HAD SURGED INTO THE LOWER 60S OVER THE FAR
SOUTHERN PART OF THE FORECAST AREA...BUT NOW THAT THE SUN IS
SETTING EXPECT THAT TO FALL BACK. MEANWHILE THE COLD FRONT WAS
MAKING EASTWARD PROGRESS ACROSS CENTRAL IA AS THE SECONDARY LOW
ALONG THE MN/IA BORDER MOVED NORTHEAST. FINALLY...FURTHER NORTH
THE REGION REMAINS LOCKED INTO THE COOL AIR AND MIXED
PRECIPITATION. FROM REPORTS RECEIVED IN WESTERN AND NORTH CENTRAL
WI...OPTED TO EXTEND THE ADVISORY THROUGH 06Z...AND PRECIPITATION
WILL CONTINUE AND TEMPERATURES WILL LIKELY NOT BUDGE.
SHORT TERM MESOSCALE MODELS ARE HANDLING THE SITUATION REASONABLY
WELL...AND HAVE FOLLOWED THE HRRR AND ARXLAPS MODEL RUNS FOR
UPDATES THIS EVENING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CDT SUN APR 14 2013
UPPER LEVEL RIDGING TRANSITIONS OVER THE UPPER MISSISSIPPI RIVER
VALLEY WITH THE EXIT OF THE LOW PRESSURE SYSTEM. THE 14.12Z GFS/NAM
WOULD BRING PIECES OF UPPER LEVEL ENERGY ACROSS THE TOP OF THE
RIDGE...WHILE OVER IA/NORTHERN ILL THEY BOTH SUGGEST AN AREA OF LOW
LEVEL WARM AIR ADVECTION/ISENTROPIC UPGLIDE/SLOPING FRONTOGENETIC
LIFT. BOTH AREAS COULD HAVE ENOUGH FORCING FOR LIGHT PCPN
PRODUCTION...AND THIS IS REFLECTED IN THE GFS/NAM QPF FIELDS. BETTER
CHANCES WOULD BE TO THE SOUTH. HOWEVER...SATURATION LOOKS TO BE AN
ISSUE. NORTH-SOUTH RUNNING X-SECTIONS AND BUFKIT SOUNDINGS SHOW AN
INCREASE IN MOISTURE FROM THE SOUTH...MOSTLY CONFINED AROUND 700
MB...WITH A RELATIVELY DRY ATMOSPHERE SUB 850 MB. THINK THERE WILL
BE ENOUGH LIFT TO WORK WITH THE AVAILABLE SATURATION TO GET THROUGH
THAT DAY LAYER...MOSTLY AS SPRINKLES TO LIGHT SHOWERS. ACCUMULATIONS
LOOK MINIMAL AT THE MOMENT...WITH CHANCES CONFINED TO PARTS OF
NORTHEAST IA/SOUTHWEST WI.
STORM SYSTEM STILL SLATED TO IMPACT THE AREA IN THE WED NIGHT/THU
TIME FRAME...WITH THE GFS/ECMWF BRINGING A SFC LOW FROM THE SOUTHERN
PLAINS TO ACROSS NORTHERN ILL BY 06Z THU. THE GEM IS A BIT FARTHER
NORTH...BUT HAS SIMILAR TIMING. CURRENT TRACK WOULD ALLOW FOR THE
SYSTEM TO BRING A GOOD AMOUNT OF LOW LEVEL WARM AIR
NORTHWARD...WHICH WOULD RESULT IN MAINLY RAIN FOR THE LOCAL FORECAST
AREA...AND THE SYSTEM/S DEFORMATION SNOW BAND LAYING UP ACROSS
NORTHERN MN. THAT SAID...THE MODELS HAVE BEEN JUMPING AROUND QUITE A
BIT...SO CONFIDENCE IS SHAKY IN JUST HOW THIS WILL PLAY OUT. CHANCES
FOR PCPN LOOK FAIRLY HIGH...EVEN LIKELY...BUT JUST WHAT WILL FALL
AND HOW MUCH IS STILL UNCERTAIN. CAN/T RULE OUT ANOTHER SHOT FOR
LATE SEASON SNOW.
CYCLONIC FLOW POST THIS STORM SYSTEM COULD KEEP SOME SMALL PCPN
CHANCES LINGERING INTO NEXT WEEKEND. THERE WILL ALSO BE ANOTHER SHOT
OF UNSEASONABLY COLD AIR. HIGHS WILL BE STUCK IN THE 40S
THU-FRI...WITH BELOW FREEZING LOWS.
&&
.AVIATION...TONIGHT AND TUESDAY
712 PM CDT SUN APR 14 2013
DIFFICULT FORECAST THIS EVENING WITH SECONDARY LOW AND PASSAGE OF
BOTH WARM AND COLD FRONTS ANTICIPATED. RAIN AND EVEN THE POSSIBILITY
OF ISOLATED THUNDER AS THESE FEATURES PASS. VISIBILITY COULD
BRIEFLY FALL BELOW 2 MILES IN THE HEAVIEST RAIN FOR A TIME THIS
EVENING. ANTICIPATE THAT THE FRONT WILL PASS KRST PRIOR TO
MIDNIGHT...AND THE KLSE AREA JUST AFTER MIDNIGHT. THIS SHOULD PUT
AN END TO THE RAIN CHANCES...WITH CLEARING SKIES. WILL BE A BIT
BREEZY FROM THE SOUTHWEST HOWEVER.
&&
.HYDROLOGY...THIS WEEK
ISSUED AT 310 PM CDT SAT APR 12 2013
THE CURRENT PRECIPITATION EVENT IS STILL ON TRACK TO PRODUCE BETWEEN
1 AND 1.5 INCHES OF LIQUID ACROSS MUCH OF THE REGION. THE SLOWER
PROGRESSION OF THE STORM SYSTEM WILL SHIFT THE AXIS OF HEAVIER
RAINFALL A BIT WESTWARD...NOW MORE ALONG AND EAST OF THE MISSISSIPPI
RIVER. LATER THIS EVENING AS THE COLD FRONT CROSSES...CONVECTION
COULD LEAD TO ISOLATED HIGHER RAINFALL AMOUNTS WITH SOME 2.0 INCH
TOTALS POSSIBLE. REGARDLESS...THE FORECAST QPF BRINGS ANOTHER ROUND
OF SIGNIFICANT RISES ON THE BLACK AND KICKAPOO RIVER BASINS TO JUST
SHY OF FLOOD STAGE. ON THE TREMPEALEAU RIVER AT DODGE...A
CONTINUATION OF MINOR FLOODING IS EXPECTED. OTHER TRIBUTARIES ACROSS
SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WESTERN WISCONSIN WILL
SEE WITHIN-BANKFULL RISES OVER THE NEXT FEW DAYS. THE CAVEAT IS IF
OBSERVED RAINFALL TONIGHT IS MUCH HIGHER THAN FORECAST...THEN FLOOD
WARNINGS WOULD BE NEEDED FOR A FEW SITES ON THE KICKAPOO AND
BLACK...SO THOSE WITH INTERESTS ON AREA RIVERS SHOULD STAY TUNED TO
THE LATEST RIVER STATEMENTS AND FORECASTS.
THE MAIN STEM OF THE MISSISSIPPI RIVER WILL REMAIN NEARLY STEADY OR
SEE A GRADUAL UPTICK THIS WEEK AS RAIN AND SNOWMELT TODAY/TONIGHT
WORKS ITS WAY DOWNSTREAM. THE ONLY EXCEPTION IS AT MCGREGOR
IOWA...WHERE THE RIVER LEVEL RISES ENOUGH SUCH THAT BY WEDNESDAY
NIGHT INTO THURSDAY IT APPROACHES FLOOD STAGE.
LOOKING AHEAD...ANOTHER SYSTEM SYSTEM LOOKS TO IMPACT THE ENTIRE
REGION WEDNESDAY NIGHT AND THURSDAY. CURRENT HPC DAY 4-5 QPF POINTS
TO ANYWHERE FROM 3/4 TO 1.5 INCHES OF LIQUID. THESE AMOUNTS
CERTAINLY WOULD INITIATE SOME AND/OR PROLONG FLOODING CONCERNS
ACROSS THE REGION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
712 PM CDT SUN APR 14 2013
WI...WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM....RIECK
AVIATION...MW
HYDROLOGY....ZT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
648 PM CDT SUN APR 14 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ELONGATED LOW
PRESSURE SPINNING ALONG THE IOWA/NEBRASKA BORDER THIS
AFTERNOON...AND A SURFACE WARM FRONT EXTENDING EASTWARD ACROSS
NORTHERN ILLINOIS. SOUTH OF THE WARM FRONT...TEMPERATURES ARE IN
THE 60S AND 70S. BUT NORTH OF THE FRONT...A 50KT SSW LLJ IS LEADING TO
A BAND OF PRECIPITATION WHICH IS NOW PUSHING INTO THE NORTHERN
SECTIONS OF THE BADGER STATE. TEMPERATURES REMAIN IN THE 20S AND
30S WITHIN THIS BAND OF PRECIP...WHERE LOCATIONS OVER CENTRAL
WISCONSIN HAVE PICKED UP A QUICK 2-3 INCHES OF WET SNOW. A FEW
SPOTTER REPORTS HAVE CONFIRMED WHAT DUAL POL IS SHOWING...THAT SNOW
IS MIXING WITH RAIN AND SLEET...WITH THE CHANGE OVER NOW SPREADING
INTO SOUTHERN MARATHON AND SHAWANO COUNTIES. ADDITIONALLY...SURFACE
WET BULB ZERO TEMPS ARE SPREADING NORTHEAST INTO EAST-CENTRAL
WISCONSIN...SO SHOULDNT SEE TOO MUCH MORE ACCUMS IN THESE AREAS.
STILL EXPECTING THE MODERATE TO HEAVY SNOW TO SPREAD INTO
NORTH-CENTRAL WISCONSIN THIS AFTERNOON WHERE A QUICK 3 INCHES WILL
LIKELY FALL. WILL CONTINUE TO HANDLE THE SNOWFALL WITH SPS
UPDATES. PRECIP CONTINUES TO BE THE MAIN FORECAST CONCERN FOR THIS
FORECAST.
TONIGHT...LOW PRESSURE WILL OCCLUDE AS IT LIFTS NORTH OVER SOUTHERN
MINNESOTA...WHILE THE OCCLUDED/COLD FRONT WILL SWEEP ACROSS THE AREA
LATE THIS EVENING AND THROUGH THE OVERNIGHT HOURS. SNOW/SLEET LOOK
TO BE ONGOING OVER NORTH-CENTRAL WISCONSIN AT THE START OF THE
EVENING WHILE CONDITIONS LOOK TO BE DRY FOR A PERIOD OVER
EAST-CENTRAL AND POSSIBLY FAR NORTHEAST WISCONSIN. THIS DRY PERIOD
OVER THE EAST WILL BE SHORT-LIVED HOWEVER...AS A BAND OF SHOWERS AND
EMBEDDED THUNDERSTORMS WILL MOVE THROUGH ALONG THE OCCLUDED/COLD
FRONT. PROGGED SOUNDINGS INDICATE THAT PTYPE SHOULD BE MAINLY RAIN
ACROSS THE REGION BY THE TIME THIS BAND ARRIVES...WHICH WILL LOOK TO
DUMP AROUND 0.75 INCHES OF RAIN OVER WESTERN SECTIONS OF THE CWA.
AMOUNTS SHOULD DROP OFF TO THE EAST AS INSTABILITY IS LOST THROUGH
THE NIGHT. BEST CHANCES OF THUNDER LOOK TO OCCUR OVER CENTRAL AND
EAST-CENTRAL AND WILL KEEP IT IN THE FORECAST. TEMPERATURES WILL
LIKELY PEAK LATE IN THE EVENING OR EARLY OVERNIGHT...JUST AHEAD OF
THE FRONT. LOWS IN THE 30S AND 40S.
MONDAY...OCCLUDED LOW PRESSURE WILL LIFT NE ACROSS NORTHERN
MINNESOTA. PRECIP WILL HAVE EXITED ALONG THE FRONT BY THE START OF
THE PERIOD AND SKIES WILL LIKELY TURN MOSTLY CLEAR FOR A PERIOD
DURING THE MORNING. HOWEVER...AS COLDER AIR FILTERS IN FROM THE
WEST AND MID-LEVEL TEMPS COOL...STEEPENING LOW LEVEL LAPSE RATES AND
WRAP AROUND MOISTURE WILL LEAD TO INCREASING CLOUDS FROM LATE
MORNING THROUGH THE REST OF THE DAY. COULD SEE A FEW INSTABILITY
RAIN AND SNOW SHOWERS DEVELOP OVER CENTRAL AND NORTHEAST WISCONSIN
IN THE AFTERNOON. GUSTY SOUTHWEST WINDS WILL BRING IN THE WARMEST
TEMPS THE AREA HAS SEEN IN SOME TIME...AND WILL GO WITH HIGHS
RANGING FROM THE LOW 40S NORTH TO THE MID 50S NEAR LAKE MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
FLOOD POTENTIAL IS PROBABLY THE MAIN CHALLENGE FOR THIS FORECAST
PERIOD. THE COLD FRONT MOVES THROUGH MONDAY WITH DRY BUT
SEASONABLE AIR FOLLOWING FOR MONDAY NIGHT THROUGH TUESDAY NIGHT.
SNOW WILL PROBABLY BE GONE OVER MUCH OF THE AREA BELOW 1000 FT
ELEVATION BY THEN WITH THAT SNOW MELT PROBABLY CONTRIBUTING TO
RISES OF THE WOLF RIVER AND SMALL STREAMS OVER EAST CENTRAL
WISCONSIN. MODELS ARE NOW IN GENERAL AGREEMENT WITH SURFACE LOW THAT
MOVES NORTHEAST FROM SOUTHERN PLAINS TO LOWER MICHIGAN WEDNESDAY
THROUGH THURSDAY. LOOKS LIKE THIS WILL BE A LARGELY RAIN EVENT
UNLESS THE STORM TRACKS FURTHER SOUTH. A RAIN EVENT COUPLED BY
SNOW MELT IN THE NORTH WILL LIKELY CAUSE SOME FLOODING OF SMALL
STREAMS AROUND THE AREA BY THURSDAY BUT SIGNIFICANTLY COLDER AND
DRIER AIR WILL SLOW SNOW MELT FRIDAY AND SATURDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 634 PM CDT SUN APR 14 2013
MAIN AVIATION CONCERNS ARE FREEZING RAIN OVER NC WI EARLY THIS EVG...
THE POTENTIAL FOR TSTMS ACROSS MAINLY C/EC WI MID-EVENING TO VERY
EARLY MONDAY MORNING...AND LLWS. WIDESPREAD MVFR/IFR CONDITIONS
ARE ANTICIPATED TONIGHT...WITH MVFR CONDITIONS IMPROVING TO VFR
ON MONDAY.
WARM AIR ALOFT WAS SURGING NORTHWARD EARLY THIS EVG...CAUSING SNOW
OVER FAR NORTHERN WI TO CHANGE TO SLEET AND FREEZING RAIN. SURFACE
TEMPS WERE STILL IN THE UPPER 20S/LOWER 30S OVER NC WI...MAINLY
NORTH OF CWA/AUW. EXPECT SEVERAL MORE HOURS OF FZRA OVER FAR N WI...
BUT CWA/AUW SHOULD CHANGE TO RAIN BY AROUND 01Z...AND RHI BY AROUND
03Z.
WIDESPREAD LIGHT TO MODERATE RAIN WILL SPREAD BACK ACROSS THE REST
OF THE FCST AREA LATER THIS EVG AND OVERNIGHT...AS A SFC LOW AND
ASSOCIATED OCCLUDED FRONT MOVE THROUGH. A SMALL AREA OF TSTMS HAS
DEVELOPED OVER NORTHERN IA...AND MAY AFFECT AT LEAST THE CWA/AUW
TAF SITES BETWEEN 03Z-05Z. BACKED OFF ON THE PREVAILING THUNDER
AT THOSE TAFS SITES...BUT KEPT A TEMPO GROUP FOR TSTMS. WILL
JUST WATCH THE OTHER TAF SITS FOR POSSIBLE INCLUSION OF THUNDER
AS THE EVG PROGRESSES.
LLWS WILL CONTINUE ACROSS THE REGION UNTIL THE OCCLUDED FRONT
MOVES THROUGH OVERNIGHT. THE LLWS SHOULD WANE AT THE TAF SITES
FROM WEST TO EAST BETWEEN 07Z-09Z. THE PCPN IS ALSO EXPECTED TO
END AFTER THE FRONT MOVES THROUGH.
STRONG SW WINDS ARE EXPECTED TO DEVELOP BY AROUND MIDDAY MONDAY...
WITH GUSTS TO 30-35 KTS LIKELY.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN APR 14 2013
CONTINUED CONCERNS FOR FLOODING ISSUES GIVEN EXPECTED
QPF WITH THE FRONTAL PASSAGE TONIGHT. AN ADDITIONAL THREE QUARTERS
TO AN INCH OF PRECIP MAY FALL OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN BY MONDAY MORNING. WARMER TEMPERATURES TONIGHT AND MONDAY
WILL ADD SNOW MELT INTO THE EQUATIONS. CONCERNS ADDRESSED IN CURRENT
ESF PRODUCT AND RIVER FLOOD STATEMENTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 306 PM CDT SAT APR 13 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
SPINNING OVER SOUTHEAST ONTARIO WHILE A WEAK SURFACE RIDGE AXIS
EXTENDS FROM CENTRAL CANADA TO THE GULF COAST. EMBEDDED SHORTWAVE
TROUGH OVER NORTHWEST WISCONSIN AND STEEP LOW LEVEL LAPSE RATES ARE
CONTRIBUTING TO SCT SNOW SHOWERS OVER NORTHERN AND ALSO CENTRAL
WISCONSIN THIS AFTERNOON...THOUGH BETWEEN THESE AREAS OVER
EAST-CENTRAL WISCONSIN HAVE REMAINED DRY FOR MOST OF THE DAY. THESE
SNOW SHOWERS SHOULD CONTINUE THROUGH EARLY THIS EVENING.
MEANWHILE...THE NEXT STORM SYSTEM IS MOVING OVER THE NORTHERN
ROCKIES AND IS DUE TO IMPACT THE REGION TOMORROW. PRECIPITATION AND
IMPACTS FROM THIS SYSTEM ARE THE MAIN FORECAST CONCERNS.
TONIGHT...SHORTWAVE TROUGH MOVING THROUGH NORTHWEST WISCONSIN WILL
EXIT OVER NORTHERN LAKE MICHIGAN DURING THE EVENING. INCREASING
SUBSIDENCE AND NOCTURNAL COOLING BEHIND THE WAVE WILL END SNOW
SHOWER CHANCES...BUT STILL PLENTY OF CLOUD COVER UPSTREAM WITHIN LOW
LEVEL CONVERGENCE. SO WILL START SKY CONDITIONS AS MOSTLY CLOUDY
BEFORE TRANSITIONING TO PARTLY CLOUDY SKIES AS SURFACE RIDGE AXIS
BUILDS INTO THE REGION. THEN AFTER MIDNIGHT...CLOUDS WILL BE ON THE
INCREASE AS AN 850MB WARM FRONT LIFTS NE ACROSS THE MID-MISSISSIPPI
VALLEY. SOUTHWEST WINDS AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM
OVER THE CENTRAL PLAINS WILL ADVECT GULF MOISTURE INTO SOUTHWEST
WISCONSIN BY DAYBREAK. THE INCREASE IN MOISTURE COMBINED WITH
INCREASING FORCING NORTH OF THE WARM FRONT WILL LEAD TO PRECIP
APPROACHING CENTRAL WISCONSIN LATE TONIGHT. PROGGED SOUNDINGS
INDICATE A SNOW/SLEET MIX LOOKS TO BE THE PTYPE AT ARRIVAL. LOW
TEMPS TO OCCUR EARLY OVERNIGHT...BEFORE CLOUDS THICKEN LATE.
SUNDAY...SURFACE LOW PRESSURE WILL MOVE NE ACROSS IOWA AND INTO
SOUTHERN OR CENTRAL MINNESOTA...WHILE THE 850MB WARM FRONT WILL LIFT
NORTH INTO NORTHERN WISCONSIN BY LATE AFTERNOON. 50KTS OF SW FLOW
AT 850MB WILL CAUSE AN FGEN INDUCED BAND OF PRECIPITATION TO LIFT
NORTH OVER THE COURSE OF THE MORNING THROUGH ABOUT MID-AFTERNOON.
ALTHOUGH AIR FROM THE RECEDING HIGH IS NOT AS COLD OR DRY AS THE
EVENT OVER THE PAST WEEK...IT STILL SHOULD BE SUFFICIENTLY COLD FOR
PRECIPITATION TYPE TO BE PREDOMINATELY SNOW AND SLEET FOR THE
MORNING...THOUGH SOME RAIN SHOULD MIX IN WITH THE FROZEN PRECIP BY
LATE MORNING OVER CENTRAL AND EAST-CENTRAL WISCONSIN AS SURFACE
TEMPS WARM. COULD SEE AN INCH OR TWO OF ACCUMULATION OVER CENTRAL
WISCONSIN DURING THE AM HOURS. AS TEMPS WARM FURTHER IN THE
AFTERNOON...PRECIP WILL CHANGE TO ALL RAIN OVER CENTRAL AND
NORTHEAST WISCONSIN...WHILE A MIX OF SNOW/SLEET/RAIN WILL CONTINUE
OVER NORTH-CENTRAL WISCONSIN. NORTH-CENTRAL WISCONSIN COULD ALSO
SEE A COUPLE INCHES OF ACCUMULATION. THOUGH PRECIP RATES COULD BE
BEEFY AT TIMES...AM COUNTING ON DAYTIME HEATING TO SUFFICIENTLY WARM
ROAD TEMPS ENOUGH TO PREVENT WIDESPREAD HAZARDOUS TRAVEL. TEMPS
SHOULD TOP OUT IN THE MID 30S NORTH TO LOW 40S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 306 PM CDT SAT APR 13 2013
UPPER LOW WILL LIFT NORTH ACROSS NORTHERN MINNESOTA SUNDAY NIGHT
AS OCCLUDED SURFACE FRONT MOVES THROUGH AND CAUSES THE RAIN TO
TAPER OFF TO SHOWERS. MONDAY WILL BE BLUSTERY BUT MILD AS 925MB
TEMPERATURES RISE A FEW DEGREES ABOVE FREEZING WITH DECENT MIXING
DESPITE MOSTLY CLOUDY SKIES. WENT A COUPLE OF DEGREES COLDER THAN
MOS GUIDANCE AS THERE WILL STILL BE SNOW ON THE GROUND OVER MUCH
OF THE AREA OR AT LEAST COLD AND WET GROUND. MONDAY NIGHT AND
TUESDAY SHOULD BE MOSTLY DRY AS BIG SURFACE HIGH OVER CANADA TRIES
TO EDGE INTO THE NORTHERN GREAT LAKES. MODELS AGREE THAT A SURFACE
WAVE WILL LIFT NORTH FROM THE SOUTHERN PLAINS TO LOWER MICHIGAN
WEDNESDAY AND WEDNESDAY NIGHT. THE TRACK IS A BIT TOO FAR WEST FOR
SIGNIFICANT SNOW BUT THERE SHOULD BE SOME AT THE START AND END
ESPECIALLY IN THE NORTH. THE SYSTEM IS STILL WAY UPSTREAM SO THAT
COULD CHANGE. MUCH COOLER AIR ARRIVES FRIDAY AND SATURDAY AS THE
SYSTEM GOES BY AND ARCTIC HIGH OVER CENTRAL CANADA MAKES A PUSH
TOWARDS THE SOUTH. SOME INSTABILITY SNOW AND RAIN SHOWERS LIKELY
FRIDAY WITH LAKE ENHANCEMENT IN VILAS COUNTY THURSDAY NIGHT AND
FRIDAY.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1236 PM CDT SAT APR 13 2013
VARIABLE CIGS THIS AFTERNOON UNDER AN UPPER LEVEL LOW
PRESSURE SYSTEM. SOME SCT SNOW SHOWERS CAN BE EXPECTED ACROSS THE
REGION WHICH WILL HAVE POTENTIAL TO DROP VSBYS TO MVFR. SNOW
SHOWERS TO DIMINISH BY EARLY THIS EVENING AND WILL SEE A FEW HOURS
OF CLEARING. THEN A WARM FRONT WILL LIFT QUICKLY TO THE NE LATE
TONIGHT INTO SUNDAY THAT WILL QUICKLY LOWER CIGS AND BRING BACK
PRECIPITATION TO THE REGION BY MID-MORNING. LATEST MODEL SOUNDINGS
INDICATE PRECIPITATION STARTING OUT AS A SNOW/SLEET MIX BEFORE
CHANGING OVER TO RAIN/SLEET BY MIDDAY. CIGS/VSBYS TO APPROACH IFR IN THE
PRECIP.
&&
.HYDROLOGY...
FLOODING CONCERNS HAVE EASED AS COLDER AIR HAS SLOWED THE ONGOING
SNOWMELT. HOWEVER...ANOTHER SYSTEM IS FORECAST TO AFFECT THE
REGION ON SUNDAY AND SUNDAY NIGHT AND PROBABLY RESUME THE RISK OF
RIVER FLOODING AS MORE PCPN FALLS. WL RE-ISSUE THE ESF DETAILING
THE SITN. FLOODING CONCERNS COULD CONT LATER NEXT WEEK...AS YET
ANOTHER SYSTEM TAKES AIM ON NE WI. THERE ARE STILL QUESTIONS AS TO
THE EVENTUAL TRACK OF THE SFC LOW AND WHETHER THE ASSOCIATED PCPN
FALLS AS RAIN OR SNOW.
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1201 AM MDT SAT APR 13 2013
.UPDATE...
ISSUED AT 915 PM MDT FRI APR 12 2013
INHERITED FORECAST IN GOOD SHAPE TONIGHT. LATEST HRRR CONTINUES TO
POINT TO AT LEAST SOME PATCHY FOG/LOW STRATUS DEVELOPMENT ACROSS
THE EASTERN PLAINS TONIGHT. IN FACT...LATEST OBSERVATIONS ALONG
THE I25 CORRIDOR AS WELL AS IN THE KIMBALL VICINITY ARE ALREADY
RECORDING CLOUDS DECKS BELOW 3000 FEET. THIS LINES UP WELL WITH
THE 11-3.9 SATELLITE FOG PRODUCT. IN A RECENT UPDATE...INCREASED
CLOUDS AS WELL AS ADDED MENTION OF FOG TO MUCH OF THE EASTERN
PLAINS. HAVE ALSO REMOVED FOG MENTION IN THE LARAMIE VALLEY AS
WIND SPEEDS ARE ANTICIPATED TO REMAIN TOO HIGH FOR ITS
DEVELOPMENT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 331 PM MDT FRI APR 12 2013
PLENTY OF SHORT TERM CHALLENGES WITH THIS FORECAST PACKAGE.
CURRENTLY...UPPER LEVEL DISTURBANCE THAT BROUGHT THE MODERATE SNOW
TO PLATTE AND SOUTHERN CONVERSE COUNTY THIS MORNING IS NOW PUSHING
OFF INTO WESTERN NEBRASKA THIS AFTERNOON. STILL QUITE A BIT OF
RETURNS ON THE CHEYENNE RADAR...EVEN SOME LIGHTNING STRIKES OVER
NORTHERN AND NORTHEASTERN COLORADO...BUT FOR THE MOST
PART...WIDESPREAD SNOW HAS COME TO AN END AS TEMPERATURES HAVE
CLIMBED INTO THE UPPER 30S. WENT AHEAD AND CANCELLED THE SNOW
ADVISORY WE ISSUED THIS MORNING AS UPPER SHORT WAVE MOVES EAST.
REMAINING SHOWER ACTIVITY SHOULD DISSIPATE OUT WITH LOSS OF
DAYTIME HEATING AFTER SUNSET.
ATTENTION TURNS TO WINDS TONIGHT. UPPER RIDGE AXIS LOOKS TO PASS
OVER THE AREA BY MIDNIGHT TONIGHT. UP UNTIL THAT POINT...MAY SEE
SOME EVENING FOG AS WE HAVE SEEN THE PAST FEW EVENING. WEST TO
SOUTHWESTERLY WINDS BEGIN TO INCREASE SIGNIFICANTLY TOWARDS 12Z
SATURDAY WITH GFS FORECASTING 50KTS OUT BY ALBANY COUNTY. THIS IN
RESPONSE TO A FRONTAL SYSTEM MOVING INTO NORTHWEST WYOMING. BY 18Z
SATURDAY...WE SEE THE UPPER LEVEL JET...ON THE ORDER OF 110KTS
PUSHING INTO CENTRAL WYOMING. OUR WIND PRONE AREAS SHOULD BE CLOSE
TO HIGH WIND WARNING CRITERIA BY THAT TIME WITH BREEZY WINDS
ELSEWHERE. WILL GO AHEAD AND ISSUE A HIGH WIND WATCH FOR SATURDAY
AFTERNOON FOR THESE AREAS. LATER SHIFTS WILL NEED TO WATCH OTHER
AREAS AS LATEST MOS GUIDANCE IS SHOWING PRETTY STRONG WINDS AT
RAWLINS AND LARAMIE. CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO
ISSUE A WATCH FOR THOSE AREAS.
FRONT THEN LOOKS TO MOVE THROUGH SOUTHERN WYOMING BY SATURDAY
EVENING. MODELS DO DEPICT SOME PRETTY GOOD QPF OVER THE SNOWY AND
SIERRA MADRE RANGES AT THIS TIME AND WE WILL PROBABLY NEED A SNOW
ADVISORY FOR THOSE LOCATIONS SATURDAY NIGHT INTO SUNDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 331 PM MDT FRI APR 12 2013
A STRONG UPPER LOW WILL SHIFT EAST OF THE FORECAST AREA ON
SUNDAY...WITH A COLD FRONT DROPPING SOUTH THROUGH THE AREA SUNDAY
EVENING. AHEAD OF THE FRONT...THE SFC PRESSURE GRADIENT WILL REMAIN
FAIRLY STRONG AS A SFC LOW DEEPENS AHEAD OF THE MAIN UPPER LOW
OVER THE NORTHERN PLAINS. SO EXPECTING MODERATE TO STRONG WESTERLY
WINDS ON SUNDAY WITH THE PRESSURE GRADIENT IN PLACE AHEAD OF THE
COLD FRONT. SUBSIDENCE IN THE WAKE OF THE DEPARTING SYSTEM ALONG
WITH THE DOWNSLOPE WINDS SHOULD KEEP CONDITIONS MOSTLY DRY...WITH
MAYBE A FEW LIGHT SNOW SHOWERS ALONG THE FRONT AS IT DROPS SOUTH
IN THE EVENING IN ADDITION TO THE WESTERN SLOPES OF THE MOUNTAINS
DUE TO UPSLOPE FORCING. THE FRONT LOOKS TO STALL OVER THE
MOUNTAINS...WITH NORTHEAST UPSLOPE FLOW STRENGTHENING SUNDAY NIGHT.
THE NEXT UPPER SYSTEM DIGGING INTO THE FOUR CORNERS REGION ON MONDAY
WILL INDUCE STRONG SFC PRESSURE FALLS OVER THE GREAT BASIN ON SUNDAY
NIGHT AND MONDAY. SO ON TOP OF THE POST-FRONTAL UPSLOPE FLOW
DEVELOPING ACROSS THE CWA...THE INCREASING PRESSURE GRADIENT FORCING
DUE TO THE INTENSIFYING LOW WILL DEEPEN THE UPSLOPE COMPONENT
EVEN FURTHER. IN ADDITION...STILL LOOKING AT MIDLEVEL ENERGY
EJECTING OUT AHEAD OF THE DEEPENING UPPER LOW AND MOVING OVER THE
FORECAST AREA MONDAY AND TUESDAY. ALL IN ALL...STILL LOOKING AT
THE POTENTIAL FOR YET ANOTHER PERIOD FOR MODERATE TO HEAVY SNOW
BEGINNING LATE SUNDAY NIGHT AND CONTINUING THROUGH EARLY
WEDNESDAY. WILL CONTINUE TO EMPHASIZE THIS SYSTEM IN THE HWO ALONG
WITH CONTINUED TREND FOR INCREASED POPS...ESPECIALLY ALONG THE
LARAMIE RANGE...CHEYENNE RIDGE...AND WESTERN MOUNTAINS.
MODELS DIFFER QUITE A BIT WITH MOVING THIS SYSTEM TO THE EAST
WEDNESDAY NIGHT AND THURSDAY. THE ECMWF IS SIGNIFICANTLY SLOWER THAN
THE GFS AND GEM MODELS...MEANING SNOW COULD LINGER LONGER THROUGH
WEDNESDAY NIGHT AND NORTHWEST WINDS WILL REMAIN STRONGER. HOWEVER...THE
CONSENSUS SHOWS THE IMPACTS FROM THE STORM WILL DIMINISH LATE ON
WEDNESDAY...WITH NORTHWEST FLOW RETURNING TO THE CWA FOR THURSDAY.
TEMPERATURES THROUGH THE PERIOD WILL TREND MILD ON SUNDAY...THEN
MUCH COLDER MONDAY THROUGH WEDNESDAY BEHIND THE COLD FRONT AND AS
THE UPPER LOW MOVES SLOWLY OVERHEAD. TEMPS WILL SLOWLY WARM FOR
THURSDAY BUT WILL DEPEND HEAVILY ON THE SNOWPACK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 1153 PM MDT FRI APR 12 2013
AREA OF LOW STRATUS ACROSS FAR SOUTHEAST WYOMING AND THE SOUTHERN
NEBRASKA AT 06Z WILL MOVE EAST AND MOSTLY DISSIPATE BY 12Z. WEST
TO SOUTHWEST WINDS WILL INCREASE LATE TONIGHT INTO SATURDAY WITH
STRONG WINDS ALONG AND WEST OF THE LARAMIE RANGE. QUICK MOVING
SHORT WAVE WILL MOVE ACROSS THE AREA LATE TODAY INTO TONIGHT. SNOW
WILL OCCUR OVER THE MOUNTAINS OF SOUTHEAST WYOMING WITH MOST OF
THE SNOW OVER THE SNOWY AND SIERRA MADRE RANGES. MOUNTAINS WILL
BECOME OBSCURED IN THE SNOW.
&&
.FIRE WEATHER...
ISSUED AT 331 PM MDT FRI APR 12 2013
NO FIRE WEATHER CONCERNS AS CURRENT SNOW PACK CONTINUES TO MELT
AND FUELS ARE MOIST. WE DO HAVE A PRETTY WIDESPREAD WIND EVENT
SATURDAY AS A COLD FRONT APPROACHES WESTERN WYOMING. SOUTHWEST TO
WEST WINDS GUSTING IN EXCESS OF 50 MPH LOOK LIKELY FOR A LARGE
PART OF SOUTHEAST WYOMING SATURDAY. AFTERNOON HUMIDITIES SATURDAY
AND SUNDAY ONLY EXPECTED TO FALL INTO THE UPPER 20S AND LOW 30S.
UNSETTLED WEATHER RETURNS TO THE AREA THE BEGINNING OF NEXT WEEK
WITH ACCUMULATING SNOWS RETURNING TO MUCH OF THE AREA.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING
FOR WYZ106-110-116-117.
NE...NONE.
&&
$$
UPDATE...HAHN
SHORT TERM...CLAYCOMB
LONG TERM...RJM
AVIATION...SML
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
904 PM PDT SUN APR 14 2013
.SYNOPSIS...
DEVELOPING LOW PRESSURE OVER THE GREAT BASIN WILL FORCE STRONG
ONSHORE FLOW AND A DEEPENING MARINE LAYER THROUGH TUESDAY CAPABLE OF
PRODUCING DRIZZLE AND LIGHT SHOWERS. AREAS OF VERY STRONG WESTERLY
WINDS WILL AFFECT SOME MOUNTAIN PASSES AND DESERT AREAS AT TIMES
THROUGH EARLY TUESDAY. DRIER AND WARMER CONDITIONS WILL DEVELOP BY
WEDNESDAY AND CONTINUE THROUGH THE END OF THE WEEK AS HIGH PRESSURE
BUILDS OVER THE PACIFIC AND OFFSHORE FLOW PREVAILS.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
THE MARINE LAYER IS DEEPENING THIS EVENING IN RESPONSE TO STRONG
ONHSORE PRESSURE GRADIENTS AND A WELL DEVELOPED COASTAL EDDY. THE
STRATUS DECK IS PUSHING UP THROUGH 4500 FEET ALONG THE COASTAL
MOUNTAIN SLOPES...RESULTING IN POCKETS OF DENSE FOG ALONG SOME
NARROW MOUNTAIN ROADS AND INTO SOME RESORTS. SOME PATCHY DRIZZLE
HAS BEEN PREVALENT ALONG THE COAST MUCH OF THE DAY AND CONTINUES
THIS EVENING...OTHERWISE LITTLE PRECIPITATION HAS BEEN OBSERVED. THE
00Z MIRAMAR SOUNDING SHOWED A STRONG 8 DEGREE C INVERSION BASE NEAR
4K FT. PW REMAINED AT 0.80 INCH.
THE FORECAST LOOKS ON TRACK...SURFACE PRESSURE GRADIENTS HAVE
INCREASED TO GREATER THAN 12 MBS FROM SAN DIEGO TO TONOPAH AND WINDS
OVER THE MOUNTAINS AND INTO THE DESERTS HAVE RESPONDED. SUSTAINED
WESTERLY WINDS OF 15-30 MPH WERE WIDESPREAD ACROSS THE DESERTS WITH
GUSTS RANGING FROM 40 TO 65 MPH IN THE WINDIEST SPOTS WITH AREAS OF
HEAVY BLOWING DUST REPORTED. A HIGH WIND WARNING IS IN EFFECT
THROUGH TUE MORNING. GUIDANCE FROM THE FINER RESOLUTION MODELS
CONTINUES TO SUPPORT THESE WINDS INTO TUE MORNING. MODEL CROSS
SECTIONS THROUGH THE MTNS/DESERTS CONTINUE TO SHOW THE STRONGEST
MOUNTAIN WAVES ON MON EVENING. THE STRONGEST WINDS MATERIALIZE AT
THIS TIME ALONG THE UPPER DESERTS SLOPES...AND TO A LESSER DEGREE
FARTHER OUT INTO THE EASTERN PORTIONS OF THE DESERTS. THE WINDS
SHOULD SUBSIDE DURING THE DAY ON TUE AS SURFACE GRADIENTS RELAX.
WATER VAPOR IMAGERY SHOWS SEVERAL SHORT-WAVES DROPPING SOUTH OFF THE
WEST COAST. THESE WAVES WILL CARVE OUT A DEEP LONG-WAVE TROUGH
ACROSS THE WEST THROUGH TUE. IN RESPONSE...SURFACE PRESSURES WILL
REMAIN QUITE LOW AND WESTERLY WINDS WILL CONTINUE TO BLOW ACROSS
SOCAL. THE DEEPENING MARINE LAYER WILL LEAK DRIZZLE AND LIGHT RAIN
SHOWERS AT TIMES...BUT WITH LITTLE ORGANIZATION AND MODEST
ACCUMULATIONS. THE COLDEST AIR WILL ARRIVE ON TUE AS THE TROUGH
BOTTOMS OUT OVER THE REGION. AT THIS TIME THE SNOW LEVEL MAY FALL
ENOUGH FOR SOME LIGHT ACCUMULATIONS ON THE HIGHER MOUNTAIN PEAKS IN
SAN BERNARDINO AND RIVERSIDE COUNTIES. MAXIMUM TEMPERATURES WILL BE
RUNNING BETWEEN 5 AND 15 DEGREES BELOW AVERAGE THROUGH TUE. BY
WED...THE TROUGH WILL BE ON THE WAY OUT AND WESTERLY WINDS WILL TURN
NORTHERLY...SCOURING OUT THE MARINE LAYER. THE REBOUNDING HEIGHTS/
THICKNESS AND MODERATE OFFSHORE FLOW WILL BRING A WARM AND DRY
PERIOD THROUGH THE END OF THE WEEK.
PRECIP AMOUNTS AND DISTRIBUTION ARE A BIT MORE PROBLEMATIC. THE
LOCAL WRFEMS...NAM 4-KM...AND HRRR 3-KM DO NOT SHOW MUCH. EVEN WITH
THE DEEP MARINE LAYER...ADVANCING COLD AIR...AND INCREASING CYCLONIC
FLOW ALOFT ON TUE. STILL...WE WILL CONTINUE TO FORECAST SCATTERED
LIGHT PRECIP ALONG AND WEST OF THE MTNS...WITH SOME ENHANCEMENT ON
THE COASTAL SLOPES DUE TO THE STRONG UPSLOPE FLOW. THE BEST CHANCES
FOR MORE WIDESPREAD PRECIP SHOULD BE ON MON NIGHT/EARLY TUE. THE
SNOW LEVEL MAY FALL TO AROUND 5000 FEET OR LOWER ON TUE IN THE
NORTHERN MOUNTAINS...SO IF THERE IS SOME LIFT WITH THE ARRIVAL OF
THE COLDER AIR...SOME LIGHT ACCUMULATIONS OF SNOW ARE POSSIBLE.
&&
.AVIATION...
150230Z...COAST/VALLEYS...OCCASIONAL DRIZZLE WITH WIDESPREAD STRATUS
AND CONTINUES THIS EVENING AND WILL CONTINUE WITH MULTIPLE LAYERS.
BASES WILL RANGE FROM 0800 TO 3500 FT MSL WITH TOPS TO 6000 FT MSL.
TERRAIN OBSCURATIONS IS OCCURRING NEAR THE FOOTHILLS AND WILL BECOME
WORSE OVERNIGHT WITH LOCAL VIS DROPPING AT TIMES TO 3-5 MI IN
DRIZZLE AND HAZE/FOG THROUGH 18Z MONDAY.
MOUNTAINS...AREAS OF STRONG WEST WINDS WILL CONTINUE TO
INCREASE OVERNIGHT WITH AREAS OF SURFACE GUSTS 35-55 KT...MAINLY
THROUGH/EAST OF BANNING PASS. AFTER SOME LOWER WIND SPEEDS
MONDAY MORNING TO MIDDAY...WINDS COULD BE EVEN STRONGER LATE
MONDAY/MONDAY NIGHT. VIS WILL BE 6+ EXCEPT... LOCAL SFC VIS BELOW 1
MI IS POSSIBLE TONIGHT AND AGAIN MONDAY AFTERNOON/NIGHT...ON THE
COASTAL SLOPES BELOW 6000 FT MSL WHERE TERRAIN OBSCURATIONS IN
CLOUDS/FOG WILL OCCUR.
DESERTS... GUSTY WINDS ARE THE ISSUE WITH SURFACE GUSTS 35-55 KTS
WITH POSSIBLE ROTORS POSSIBLE ON MONDAY NIGHT.
&&
.MARINE...
150230Z A COASTAL EDDY WAS SE OF SAN CLEMENTE ISLAND PRODUCING WEAK
TO SOUTHERLY WIND FLOW IN THE SAN DIEGO COASTAL WATERS. THE EDDY
WILL DISSIPATE AND A STRONG W-NW WIND WILL INCREASE MONDAY...PEAKING
OVERNIGHT MONDAY AND INTO TUESDAY. THE STRONGEST WINDS WILL BE IN
THE OUTER COASTAL WATERS WHERE SUSTAINED WINDS OF 20-25 KNOTS AND
GUSTS AROUND 30 KNOTS ARE LIKELY. A SHORT-PERIOD WNW SWELL...7-9
FEET/8-10 SECONDS IS BEING GENERATED BY THIS INCREASE WINDS OFF THE
CENTRAL CALIFORNIA COAST AND MOVING SOUTHWARD DURING THE DAY MONDAY.
THIS WNW SWELL WILL COMBINE WITH A 3-FOOT LONG-PERIOD SOUTH SWELL
AND LOCAL WIND WAVES WILL BRING ROUGH CHOPPY SEAS TO 12 FEET. A
SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE INNER AND OUTER COASTAL
WATERS FOR MON NIGHT THROUGH TUE EVENING.
THE COMBINATION OF THE 2 SWELLS WILL BRING ABOVE NORMAL SURF TO THE
BEACHES...GENERALLY 4-6 FEET WITH LOCAL SETS OF 7 FEET IN ORANGE
COUNTY. THE SOUTH SWELLS WILL IMPACT ORANGE COUNTY/N SAN DIEGO
COUNTY MON THROUGH WED...AND THE WNW SHORT-PERIOD SWELL WILL IMPACT
MAINLY S SAN DIEGO COUNTY MON NIGHT/TUE...THOUGH ITS SHORT PERIOD
WILL RESULT IN LESS SURF THAN WITH THE SOUTH SWELL.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...SMALL CRAFT ADVISORY FROM 6 PM MONDAY TO 10 PM PDT TUESDAY FOR
THE SAN DIEGO COUNTY COASTAL AREAS.
HIGH WIND WARNING THROUGH 9 AM PDT TUESDAY FOR THE APPLE AND
LUCERNE VALLEYS...COACHELLA VALLEY...RIVERSIDE COUNTY
MOUNTAINS...SAN BERNARDINO COUNTY MOUNTAINS...SAN DIEGO COUNTY
DESERTS...SAN DIEGO COUNTY MOUNTAINS.
PZ...SMALL CRAFT ADVISORY FROM 6 PM MONDAY TO 10 PM PDT TUESDAY FOR
THE COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN
BORDER AND OUT 30 NM...WATERS FROM SAN MATEO POINT TO THE
MEXICAN BORDER EXTENDING 30 TO 60 NM OUT INCLUDING SAN
CLEMENTE ISLAND.
&&
$$
PUBLIC...JAD
AVIATION/MARINE...PIERCE/MAXWELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
953 PM EDT SUN APR 14 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO NEW ENGLAND FROM THE WEST OVERNIGHT
THEN MOVE OFF THE COAST MON AFTERNOON. THE HIGH MOVES FARTHER
OFFSHORE TUE WITH A WARMING TREND ACROSS SOUTHERN NEW ENGLAND. A
WEAK COLD FRONT WILL SLIP SOUTH INTO THE REGION TUE NIGHT AND
WED...POSSIBLY TRIGGERING A FEW SHOWERS. THE NEXT STORM SYSTEM
APPROACHES THE REGION FROM THE WEST ON THURSDAY AND WILL IMPACT
OUR WEATHER INTO THE WEEKEND
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
10 PM UPDATE...
ONLY MINOR TWEAKS TO THE FORECAST THIS EVENING. ADJUSTED SKIES
TOWARD LATEST RAP WHICH HAS BEEN HANDLING THE EXIT OF DIURNAL/WAVE
DRIVEN CLOUDS TO THE N AND THE CIRRUS SHIELD TO THE S WELL. ALSO
BROUGHT TEMPS AND DWPTS UP TO DATE. LOWERED OVERNIGHT MINS BY A
LITTLE BIT AS THE CLEARING NOW APPARENT OVER THE AREA HAS ALREADY
LED TO A DECOUPLING AND DECENT RADIATIONAL COOLING.
PREVIOUS DISCUSSION...
PRIOR TO 06Z...A MID-LEVEL RIDGE /AND HIGH PRESSURE BUILDING IN AT
THE SURFACE/ WILL PROVIDE IDEAL RADIATIONAL COOLING CONDITIONS.
AS A RESULT...EXPECT LOWS TO FALL INTO THE 30S REGION-WIDE WITH
A FEW UPPER 20S POSSIBLE FAR NW MA.
WINDS WILL BECOME LIGHT AND VARIABLE AFTER 00Z.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
MONDAY...IT MAY TURN OUT TO TECHNICALLY BE A MOSTLY CLOUDY
DAY...WITH ABUNDANT MID AND HIGH CLOUDINESS...ESPECIALLY IN THE
MORNING. BUT THERE WILL BE SOME FILTERED SUNSHINE THROUGH THE
CLOUDS. EXPECT SKIES TO BECOME PARTLY TO MOSTLY SUNNY OVER EASTERN
PORTIONS LATE IN THE DAY. TEMPS WILL BE MUCH WARMER THAN
TODAY...+3C EAST TO +6C WEST. HOWEVER...DUE TO EXPECTED CLOUD
COVER...HAVE CUT BACK A FEW DEGREES ON MAVMOS GUIDANCE. AM
EXPECTING HIGHS AROUND 60 IN THE INTERIOR. HOWEVER...WINDS WILL BE
SHIFTING FROM NORTHEAST TO SOUTHEAST ALONG THE COAST DURING THE
DAY. THIS EASTERLY FLOW...WHICH COULD GUST UP TO 15-18 MPH AT THE
COAST...WILL KEEP THINGS MUCH COOLER...ONLY 50 TO 55 NEAR THE
COAST IN EASTERN MA AND SOUTHERN MOST RI. ATMOSPHERE WILL REMAIN
DRY WITH DEWPTS IN THE MID-UPPER 20S INLAND TO THE LOWER 30S ALONG
THE COAST.
MONDAY NIGHT...STRONG HIGH PRESSURE MOVES FARTHER OFF THE COAST
WHILE A COLD FRONT MOVES ACROSS THE EASTERN GREAT LAKES. AN
INCREASINGLY MOIST SOUTHERLY AIR FLOW WILL PREVAIL OVER SOUTHERN
NEW ENGLAND. PREFERRED METNAM FOR HIGHER DEWPTS THAN OTHER
GUIDANCE...IN THE 30S. OVERNIGHT LOWS SHOULD BE IN THE UPPER 30S
TO AROUND 40. SKIES WILL BE PARTLY CLOUDY IN THE EAST BUT REMAIN
OR BECOME OVERCAST IN WESTERN MA AND NORTHWEST CT. A FEW SHOWERS
CANNOT BE RULED OUT WELL AFTER MIDNIGHT ACROSS SW NH...WESTERN
MA...AND NORTHERN CT... CLOSER TO THE APPROACHING FRONT.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
* MILD WORK WEEK AHEAD W/CONSIDERABLE CLOUDS AND PERIODS OF
SHOWERS.
* WIND ADVISORY MAY BE NEEDED ON TUESDAY.
* COOLER WEATHER ARRIVES BY NEXT WEEKEND.
OVERVIEW AND MODEL PREFERENCES...
14.12Z MODEL SUITE IS IN GOOD AGREEMENT FEATURING A MEAN TROF
GRADUALLY MOVING FROM WEST TO EAST ACROSS THE CONUS THROUGH THE
PERIOD...LEADING TO A PERSISTENT SOUTHWEST FLOW ALOFT OVER SOUTHERN
NEW ENGLAND. SEVERAL SHORT-WAVE DISTURBANCES WILL ROTATE THROUGH THE
TROF IMPACTING DAILY SENSIBLE WEATHER.
DETAILS...
TUESDAY...SFC HIGH PRES MOVES OFFSHORE LEADING TO A RETURN SOUTHWEST
FLOW. ALTHOUGH IT IS QUESTIONABLE WHETHER THE TRUE WARM FRONT MAKES
IT EAST OF THE HUDSON VALLEY...TEMPERATURES WILL BE NEAR SEASONABLE
LEVELS. THE BEST FORCING REMAINS NORTH OF THE REGION...SO ONLY
EXPECTING SCATTERED SHOWERS. MORE IMPORTANTLY...A STRONG SOUTHWEST
FLOW ALOFT SETS UP ACROSS THE REGION WITH 925 HPA WINDS APPROACHING
40 KNOTS BY 00Z WED. BUFKIT SOUNDINGS INDICATE THE POTENTIAL FOR
THIS MOMENTUM TO MIX DOWN TO THE SURFACE. THEREFORE...A WIND ADVISORY
MAY BE NEEDED.
WEDNESDAY...COLD FRONTAL PASSAGE OCCURS EARLY IN THE DAY...WITH HIGH
PRESSURE BUILDING INTO THE REGION. BUT THE AMOUNT OF MOISTURE IN THE
POST FRONTAL COLUMN REMAINS IN QUESTION...WITH THE ECMWF MUCH DRIER
THAN THE GFS. FOR NOW...DID A ECMWF/GFS COMPROMISE WITH PARTLY
CLOUDY SKIES ACROSS THE REGION. CANNOT RULE OUT A SHOWER...
ESPECIALLY EARLY IN THE DAY /MAINLY SOUTH OF I-90/.
THURSDAY THROUGH FRIDAY...HIGH PRESSURE MOVES OFFSHORE IN ADVANCE OF
THE NEXT STORM SYSTEM ON THURSDAY. SCATTERED SHOWERS ARE POSSIBLE ON
THURSDAY...WITH A BETTER CHANCE ON FRIDAY WITH THE APPROACH OF A
COLD FRONT. SOUTHWEST FLOW INCREASES WITH 925 HPA WINDS IN EXCESS
OF 50 KNOTS BY LATE DAY FRIDAY. AT THIS POINT...WILL HAVE TO SEE
JUST HOW MUCH OF THIS MOMENTUM CAN MAKE IT TO THE SURFACE.
NEVERTHELESS... IT IS SHAPING UP TO BE A WINDY DAY. IT SHAPING UP
TO BE THE WARMEST DAY OF THE WEEK WITH TEMPERATURES APPROACHING
70F.
SATURDAY AND SUNDAY...COLD FRONT MOVES THROUGH SOMETIME FRIDAY NIGHT
INTO THE DAY ON SATURDAY...PRESENTING THE BEST CHANCE FOR WIDESPREAD
QPF THIS WEEK. COOLER TEMPERATURES WILL FOLLOW THE FRONT...BUT STILL
NEAR SEASONABLE LEVELS.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...
THROUGH MONDAY NIGHT...HIGH CONFIDENCE. VFR CONDITIONS. W-NW WINDS
GUSTING TO 20 KT LATE THIS EVENING WILL DIMINISH EARLY TONIGHT.
LIGHTER WINDS MON WITH SEA BREEZES LIKELY...COULD REACH 15 KT AT THE
COAST. SLIGHT CHANCE OF A SHOWER IN SOUTHWEST NH/WESTERN MA/NORTHERN
CT LATE MON NIGHT.
KBOS TERMINAL...HIGH CONFIDENCE. VFR. WNW WIND GUSTS UP TO 20 KT
DIMINISHING EARLY TONIGHT. SEA BREEZES LIKELY MON.
KBDL TERMINAL...HIGH CONFIDENCE. VFR CONDITIONS THROUGH MONDAY
NIGHT. SLIGHT CHANCE OF A SHOWER LATE MON NIGHT.
OUTLOOK...TUE THROUGH FRI...
TUESDAY...MVFR IN SHRA. LLWS POSSIBLE WITH WIND GUSTS TO 40 KTS.
WEDNESDAY...MVFR IN SHRA EARLY IN THE DAY. OTHERWISE VFR.
THURSDAY TO FRIDAY...MVFR POSSIBLE IN SHRA...ESPECIALLY FRIDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
HIGH FORECAST CONFIDENCE THROUGH MON NIGHT WITH WINDS AND SEAS
BELOW SMALL CRAFT ADVISORY CRITERIA.
TONIGHT... LIGHT WINDS AS HIGH PRESSURE CRESTS OVER THE AREA. DRY
WEATHER AND GOOD VSBY CONTINUE.
MON...
HIGH PRES MOVES OFFSHORE. NE WINDS BECOME SE. DRY WEATHER AND
GOOD VSBY CONTINUE.
MON NIGHT...SE TO S WINDS INCREASE TO 10 TO 20 KT...BUT REMAIN
BELOW SCA CRITERIA.
OUTLOOK...TUESDAY THROUGH FRIDAY...
MODERATE CONFIDENCE ALL PERIODS.
TUE...SCA CONDITIONS LIKELY FOR WINDS AND SEAS.
WED...A BRIEF ROUND OF HIGH PRESSURE ALLOWS WINDS AND SEAS TO
SLACKEN. HOWEVER...SCA FOR SEAS MAY BE NEEDED...ESP OVER THE
OUTER WATERS.
THU AND FRI...INCREASING SOUTHWEST WINDS AHEAD OF AN APPROACHING
COLD FRONT. SCA CONDITIONS WITH A LOW PROBABILITY OF GALES.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GAF
NEAR TERM...DOODY/GAF
SHORT TERM...GAF
LONG TERM...JWD
AVIATION...JWD/GAF
MARINE...JWD/GAF
AREA FORECAST DISCUSSION
NWS JACKSON KY
314 AM EDT MON APR 15 2013
.UPDATE...
ISSUED AT 105 AM EDT MON APR 15 2013
UPDATED THE FORECAST TO BETTER REFLECT THE ON-GOING MEASURABLE RAIN
OVER THE NORTHEAST PORTION OF THE CWA. THIS RAIN HAS ALSO KNOCKED
DOWN TEMPERATURES...WAY OFF OF OUR FORECAST DIURNAL TRACK SO THAT
THEY ARE NEAR THE LOWS IN THE SOUTH WHILE STILL DECENT IN THE NORTH.
HAVE ADDRESSED THIS AS WELL WITH THIS UPDATE. LIKEWISE...DECIDED TO
LOAD IN THE LATEST TD GRIDS FROM THE HRRR AS THE OTHER GUIDANCE IS
PRETTY FAR OFF...ASIDE FROM THE GMOS. THE LIGHT RAIN WILL PIVOT OUT
OF THE AREA BY DAWN...LINGERING THE LONGEST OVER OUR FAR EASTERN
TERRITORY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. A
FRESH SET OF ZONES WILL FOLLOW SHORTLY.
UPDATE ISSUED AT 1143 PM EDT SUN APR 14 2013
HAD TO MAKE ANOTHER QUICK UPDATE TO THE FORECAST. SURFACE
OBSERVATIONS FROM LOCATIONS SOUTH AND SOUTHEAST OF THE WEATHER OFFICE
HAVE PICKED UP ENOUGH RAIN OVER THE PAST FEW HOURS TO WARRANT HIGHER
THAN SLIGHT CHANCE POPS. A NUMBER OF RAWS...AWOS...AND OTHER
OBSERVATIONS SITES FROM WAYNE COUNTY EASTWARD TO LETCHER COUNTY HAVE
MEASURED AT LEAST A FEW HUNDREDTHS OF AN INCH OF RAIN SINCE 8 PM.
THEREFORE...DECIDED TO INCREASE PRECIPITATION CHANCES FOR THE 2 TO 6Z
TIME FRAME TONIGHT TO BETTER REFLECT ACTUAL TRENDS IN THE WEATHER.
THE APPROPRIATE CHANGES WERE MADE TO THE QPF AND WEATHER GRIDS AS
WELL BASED ON THE NEW POP FORECAST. THE REST OF THE FORECAST WAS IN
GOOD SHAPE AS IS.
UPDATE ISSUED AT 927 PM EDT SUN APR 14 2013
WITH MEASURABLE PRECIPITATION ALREADY OCCURRING BETWEEN THE TENNESSEE
BORDER AND THE HAL ROGERS PARKWAY HIGHWAY 80 CORRIDOR...WAS NECESSARY
TO UPDATE THE FORECAST TO REFLECT THE CURRENT TRENDS AND CONDITIONS.
IN A NUTSHELL...MEASURABLE PRECIPITATION IS OCCURRING EARLIER AND A
BIT FURTHER NORTH THEN THE INHERITED FORECAST WAS INDICATING...SO THE
APPROPRIATE CHANGES HAVE BEEN MADE TO BOTH THE GRIDS AND THE ZONE
FORECAST TEXT PRODUCT. THE TEMPERATURES...WIND...AND SKY COVER
FORECAST ELEMENTS ARE ALL ON TRACK FOR THE NIGHT...SO NO CHANGES WERE
MADE TO ANY OF THOSE. THE UPDATED FORECAST HAS ALREADY BEEN ISSUED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 331 PM EDT SUN APR 14 2013
HIGH CLOUDS CONTINUE TO STREAM IN FROM THE SOUTHWEST OUT AHEAD OF A
SHORT WAVE TROUGH SWINGING THROUGH THE GULF COAST STATES. THE MODELS
ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...SWINGING THIS WAVE
NORTHEAST ACROSS THE SOUTHERN APPALACHIANS TONIGHT...BEFORE EXITING
ACROSS THE MID-ATLANTIC ON MONDAY...WITH WEAK RIDGING TO FOLLOW
ACROSS THE EASTERN SEABOARD.
THE MODELS HAVE TRENDED A BIT MORE AGGRESSIVE WITH THE POPS ACROSS
SOUTHEASTERN KENTUCKY TONIGHT. GIVEN THE AGREEMENT...INCREASED POPS
SOMEWHAT...ALTHOUGH WITH THE CURRENT LOW LEVEL DRY AIR IN PLACE...AM
NOT TOO CONFIDENT THIS FAIRLY FAST MOVING SYSTEM WILL BE ABLE TO
SATURATE THE LOW LEVELS IN TIME FOR MEASURABLE PRECIPITATION.
THE THICKER CLOUDS WILL MITIGATE THE RIDGE/VALLEY SPLIT TONIGHT...WITH
MOST LOCATIONS BOTTOMING OUT IN THE LOW TO MID 50S. CLOUDS WILL BE ON
THE DECREASE BY MONDAY AFTERNOON AS SOME SHORT WAVE RIDGING FOLLOWS
IN THE WAKE OF THE EXITING SHORT WAVE TROUGH. HIGHS WILL REBOUND TO
THE MID AND UPPER 70S.
FOR MONDAY NIGHT...A WEAKENING COLD FRONT WILL ATTEMPT TO APPROACH
FROM THE NORTHWEST...BUT LOOKS TO STAY NORTH OF THE OHIO RIVER. WILL
CONTINUE WITH JUST A SLIGHT CHANCE OF A SHOWER OR STORM THREATENING
THE BLUEGRASS LATE. CLOUDS WILL BE LESS EXTENSIVE MONDAY NIGHT...AND
WITH LIGHT SOUTHERLY WINDS...THIS SHOULD SET UP MORE A RIDGE/VALLEY
SPLIT. COOLER VALLEYS WILL BOTTOM OUT IN THE LOWER 50S...WHILE RIDGES
STAY UP AT AROUND 60.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 314 AM EDT MON APR 15 2013
FORECAST CONCERNS FOR THE PERIOD CONTINUE TO REVOLVE AROUND
THUNDERSTORM CHANCES MIDWEEK AND THEN TIMING OF A FRONTAL PASSAGE
THROUGH OUR REGION LATE IN THE WORK WEEK.
MODELS CONTINUE TO BUILD AN UPPER LEVEL RIDGE INTO THE SOUTHERN
APPALACHIANS ON TUESDAY NIGHT AND WEDNESDAY. THEY ALSO INDICATE
PLENTY OF SURFACE BASED INSTABILITY ALONG WITH WEAK DISTURBANCES
PASSING OVER OUR REGION AS THEY ROUND THE TOP OF THE RIDGE. THUS
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TUESDAY
NIGHT INTO THE DAY ON WEDNESDAY. GIVEN ANY SUNSHINE AT ALL WE SHOULD
BE ABLE TO CLIMB INTO THE LOW 80S FOR MOST LOCATIONS WEDNESDAY
AFTERNOON.
STRONG SOUTHERLY FLOW WILL THEN COMMENCE WEDNESDAY NIGHT INTO THE
DAY ON THURSDAY AS AN UPPER LEVEL TROUGH BEGINS TO TREK ACROSS THE
PLAINS INTO THE MIDWEST. THIS DOWNSLOPE FLOW SHOULD DECREASE OUR
INSTABILITY AND THUNDERSTORM CHANCES ON THURSDAY...AND HELP US WARM
INTO THE LOW TO MID 80S. SURFACE WINDS ARE EXPECTED TO GUST UP TO 30
MPH DURING THE AFTERNOON HOURS AS WELL.
THE COLD FRONT IS THEN PROGGED TO PASS THROUGH EAST KENTUCKY ON
FRIDAY MORNING. IT WILL BE STRUNG OUT BY THE TIME IT REACHES US WITH
VERY LITTLE IF ANY INSTABILITY SHOWING UP IN THE PROGS AND WILL ONLY
ADVERTISE A SLIGHT CHANCE OF THUNDER IN ADVANCE OF THE FRONT
THURSDAY NIGHT...AND WITH THE FRONT ON FRIDAY. STILL CANNOT RULE OUT
THIS THING SLOWING DOWN EVEN MORE EITHER SO WILL HOLD ONTO A SMALL
POP FRIDAY NIGHT. OTHERWISE...THE WEEKEND LOOKS DRY WITH
TEMPERATURES COOLING BACK DOWN INTO THE 50S TO LOW 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 115 AM EDT MON APR 15 2013
THE SFC WAVE PASSING BY TO THE SOUTHEAST WILL CLEAR OUT THE LIGHT
RAIN FROM THE TAF SITES DURING THE EARLY MORNING HOURS AND THE REST
OF THE AREA BY DAWN. EVEN AS THE WX IMPROVES...THE CIGS WILL PROBABLY
BRIEFLY FALL TO MVFR AROUND DAWN. THE WAVE WILL EVENTUALLY GET FAR
ENOUGH EAST TO ALLOW CIGS TO CLIMB OR CLEAR OUT ENTIRELY RESUMING THE
VFR CONDITIONS BY MID MORNING MONDAY. THIS SHOULD BE THE CASE THROUGH
EVENING...THOUGH CIGS WILL LIKELY RETURN AND LOWER TOWARDS MIDNIGHT
AHEAD OF A SAGGING FRONT FROM THE NORTHWEST. WINDS WILL BE GENERALLY
LIGHT FROM THE SOUTH THROUGH THE PERIOD...THOUGH A FEW GUSTS TO 15
KTS WILL BE POSSIBLE OVER THE NEXT COUPLE OF HOURS AND AGAIN LATE
MONDAY EVENING AS THAT NEXT BOUNDARY CLOSES IN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...ABE
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
115 AM EDT MON APR 15 2013
.UPDATE...
ISSUED AT 105 AM EDT MON APR 15 2013
UPDATED THE FORECAST TO BETTER REFLECT THE ON-GOING MEASURABLE RAIN
OVER THE NORTHEAST PORTION OF THE CWA. THIS RAIN HAS ALSO KNOCKED
DOWN TEMPERATURES...WAY OFF OF OUR FORECAST DIURNAL TRACK SO THAT
THEY ARE NEAR THE LOWS IN THE SOUTH WHILE STILL DECENT IN THE NORTH.
HAVE ADDRESSED THIS AS WELL WITH THIS UPDATE. LIKEWISE...DECIDED TO
LOAD IN THE LATEST TD GRIDS FROM THE HRRR AS THE OTHER GUIDANCE IS
PRETTY FAR OFF...ASIDE FROM THE GMOS. THE LIGHT RAIN WILL PIVOT OUT
OF THE AREA BY DAWN...LINGERING THE LONGEST OVER OUR FAR EASTERN
TERRITORY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. A
FRESH SET OF ZONES WILL FOLLOW SHORTLY.
UPDATE ISSUED AT 1143 PM EDT SUN APR 14 2013
HAD TO MAKE ANOTHER QUICK UPDATE TO THE FORECAST. SURFACE
OBSERVATIONS FROM LOCATIONS SOUTH AND SOUTHEAST OF THE WEATHER OFFICE
HAVE PICKED UP ENOUGH RAIN OVER THE PAST FEW HOURS TO WARRANT HIGHER
THAN SLIGHT CHANCE POPS. A NUMBER OF RAWS...AWOS...AND OTHER
OBSERVATIONS SITES FROM WAYNE COUNTY EASTWARD TO LETCHER COUNTY HAVE
MEASURED AT LEAST A FEW HUNDREDTHS OF AN INCH OF RAIN SINCE 8 PM.
THEREFORE...DECIDED TO INCREASE PRECIPITATION CHANCES FOR THE 2 TO 6Z
TIME FRAME TONIGHT TO BETTER REFLECT ACTUAL TRENDS IN THE WEATHER.
THE APPROPRIATE CHANGES WERE MADE TO THE QPF AND WEATHER GRIDS AS
WELL BASED ON THE NEW POP FORECAST. THE REST OF THE FORECAST WAS IN
GOOD SHAPE AS IS.
UPDATE ISSUED AT 927 PM EDT SUN APR 14 2013
WITH MEASURABLE PRECIPITATION ALREADY OCCURRING BETWEEN THE TENNESSEE
BORDER AND THE HAL ROGERS PARKWAY HIGHWAY 80 CORRIDOR...WAS NECESSARY
TO UPDATE THE FORECAST TO REFLECT THE CURRENT TRENDS AND CONDITIONS.
IN A NUTSHELL...MEASURABLE PRECIPITATION IS OCCURRING EARLIER AND A
BIT FURTHER NORTH THEN THE INHERITED FORECAST WAS INDICATING...SO THE
APPROPRIATE CHANGES HAVE BEEN MADE TO BOTH THE GRIDS AND THE ZONE
FORECAST TEXT PRODUCT. THE TEMPERATURES...WIND...AND SKY COVER
FORECAST ELEMENTS ARE ALL ON TRACK FOR THE NIGHT...SO NO CHANGES WERE
MADE TO ANY OF THOSE. THE UPDATED FORECAST HAS ALREADY BEEN ISSUED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 331 PM EDT SUN APR 14 2013
HIGH CLOUDS CONTINUE TO STREAM IN FROM THE SOUTHWEST OUT AHEAD OF A
SHORT WAVE TROUGH SWINGING THROUGH THE GULF COAST STATES. THE MODELS
ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...SWINGING THIS WAVE
NORTHEAST ACROSS THE SOUTHERN APPALACHIANS TONIGHT...BEFORE EXITING
ACROSS THE MID-ATLANTIC ON MONDAY...WITH WEAK RIDGING TO FOLLOW
ACROSS THE EASTERN SEABOARD.
THE MODELS HAVE TRENDED A BIT MORE AGGRESSIVE WITH THE POPS ACROSS
SOUTHEASTERN KENTUCKY TONIGHT. GIVEN THE AGREEMENT...INCREASED POPS
SOMEWHAT...ALTHOUGH WITH THE CURRENT LOW LEVEL DRY AIR IN PLACE...AM
NOT TOO CONFIDENT THIS FAIRLY FAST MOVING SYSTEM WILL BE ABLE TO
SATURATE THE LOW LEVELS IN TIME FOR MEASURABLE PRECIPITATION.
THE THICKER CLOUDS WILL MITIGATE THE RIDGE/VALLEY SPLIT TONIGHT...WITH
MOST LOCATIONS BOTTOMING OUT IN THE LOW TO MID 50S. CLOUDS WILL BE ON
THE DECREASE BY MONDAY AFTERNOON AS SOME SHORT WAVE RIDGING FOLLOWS
IN THE WAKE OF THE EXITING SHORT WAVE TROUGH. HIGHS WILL REBOUND TO
THE MID AND UPPER 70S.
FOR MONDAY NIGHT...A WEAKENING COLD FRONT WILL ATTEMPT TO APPROACH
FROM THE NORTHWEST...BUT LOOKS TO STAY NORTH OF THE OHIO RIVER. WILL
CONTINUE WITH JUST A SLIGHT CHANCE OF A SHOWER OR STORM THREATENING
THE BLUEGRASS LATE. CLOUDS WILL BE LESS EXTENSIVE MONDAY NIGHT...AND
WITH LIGHT SOUTHERLY WINDS...THIS SHOULD SET UP MORE A RIDGE/VALLEY
SPLIT. COOLER VALLEYS WILL BOTTOM OUT IN THE LOWER 50S...WHILE RIDGES
STAY UP AT AROUND 60.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 331 PM EDT SUN APR 14 2013
MODEL FORECASTS HAVE TRENDED A BIT WETTER SINCE YESTERDAY FOR THE
EARLY PART OF THE FORECAST PERIOD. MOIST GULF OF MEXICO AIR SHOULD
BE IN PLACE LOCALLY...ON THE SOUTH SIDE OF A FRONT STALLING OUT NEAR
THE OHIO RIVER ON TUESDAY. A WEAK SHORTWAVE TROUGH RIPPLING EAST
OVER THE REGION MAY AID DEVELOPMENT OF SHOWERS/THUNDERSTORMS ON
TUESDAY. AS THE WAVE MOVES AWAY AND HEATING IS LOST...WILL LOOK FOR
A DECREASE IN PRECIP ON TUESDAY NIGHT. HEATING ON WEDNESDAY MAY GET
SOME MORE SHOWERS/THUNDERSTORMS GOING...POSSIBLY AIDED BY ANOTHER
VERY WEAK WAVE. ON BOTH DAYS...WILL CARRY THE HIGHEST POPS IN THE
NORTHERN PART OF THE AREA CLOSEST TO THE SURFACE FRONT. THIS SHOULD
BE FOLLOWED BY ANOTHER PRECIP LULL WITH LOSS OF HEATING ON WEDNESDAY
NIGHT.
BY THURSDAY THE STALLED FRONTAL BOUNDARY SHOULD HAVE LIFTED MUCH
FURTHER NORTH...BEING DRIVEN BY A LOW PRESSURE SYSTEM TRACKING NE
OVER THE MIDWEST. WILL NOT RULE OUT SHOWERS/THUNDERSTORMS DEVELOPING
ON THURSDAY...BUT BOTH THE GFS AND ECMWF FOCUS THE BULK OF THE
PRECIP CLOSER TO THE FRONTAL BOUNDARIES TO OUR NORTH AND WEST. THE
12Z GFS DEVELOPS AN ADDITIONAL LOW PRESSURE SYSTEM ALONG THE FRONT
OVER THE MIDWEST LATE THURSDAY AND THURSDAY NIGHT...LEADING TO A
SLIGHTLY SLOWER MOVEMENT OF A STRONG LATE WEEK COLD FRONT AS
COMPARED TO EARLIER RUNS OF THE GFS OR ECMWF. EVEN SO...THE 12Z GFS
IS ONLY ABOUT 4-5 HOURS SLOWER THAN THE CONSISTENT EARLIER RUNS.
THAT BEING THE CASE...WILL STILL OPT FOR FROPA ON FRIDAY
MORNING...WHICH WOULD LIKELY YIELD TEMPS BELOW GFS MOS GUIDANCE ON
FRIDAY. HIGHEST POPS OF THE LONG TERM WILL BE IN LIKELY CATEGORY
NEAR AND BEHIND THE COLD FRONT. IT SHOULD STILL EXIT TO THE EAST BY
FRIDAY NIGHT...LEAVING DRY AND MUCH COOLER WEATHER TO FINISH THE
PERIOD. IN FACT...FROST AGAIN LOOKS LIKE IT COULD BE A CONCERN NEXT
WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 115 AM EDT MON APR 15 2013
THE SFC WAVE PASSING BY TO THE SOUTHEAST WILL CLEAR OUT THE LIGHT
RAIN FROM THE TAF SITES DURING THE EARLY MORNING HOURS AND THE REST
OF THE AREA BY DAWN. EVEN AS THE WX IMPROVES...THE CIGS WILL PROBABLY
BRIEFLY FALL TO MVFR AROUND DAWN. THE WAVE WILL EVENTUALLY GET FAR
ENOUGH EAST TO ALLOW CIGS TO CLIMB OR CLEAR OUT ENTIRELY RESUMING THE
VFR CONDITIONS BY MID MORNING MONDAY. THIS SHOULD BE THE CASE THROUGH
EVENING...THOUGH CIGS WILL LIKELY RETURN AND LOWER TOWARDS MIDNIGHT
AHEAD OF A SAGGING FRONT FROM THE NORTHWEST. WINDS WILL BE GENERALLY
LIGHT FROM THE SOUTH THROUGH THE PERIOD...THOUGH A FEW GUSTS TO 15
KTS WILL BE POSSIBLE OVER THE NEXT COUPLE OF HOURS AND AGAIN LATE
MONDAY EVENING AS THAT NEXT BOUNDARY CLOSES IN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...HAL
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
341 AM EDT MON APR 15 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER SOUTHWEST VIRGINIA IS TRACKING
INTO THE MID ATLANTIC REGION THIS MORNING. A COLD FRONT WILL APPROACH THE
AREA TUESDAY BEFORE STALLING OVERHEAD WEDNESDAY. THIS BOUNDARY
WILL RETURN NORTH AS A WARM FRONT THURSDAY BEFORE A STRONGER COLD
FRONT MOVES IN FROM THE WEST LATE FRIDAY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /TODAY/...
HIGH PRES HAS MOVED FAR ENOUGH OFFSHORE THAT ITS INFLUENCE APPEARS
TO BE WANING IN THE MID ATLC. EVEN THO THE 00Z RNK AND IAD SNDGS
WERE QUITE DRY THIS IS BEING OVERCOME BY MOISTURE W/ THE APRCHG
SHORT WV. AS A RESULT ENTIRE AREA HAS GONE OVC AND THE RAFL ASSO W/
THE UPR LVL SHORT WV HAS PUSHED N OF CHO. BOTH GFS AND NAM ARE
GIVING CHC POPS TO THE ENTIRE RGN TDA...AND HV MADE THAT
ADJUSTMENT W/ THE XCPTN OF LKLY POPS IN THE CENTRAL SHEN VLLY.
QUSTN THEN BECOMES WHAT TIME IS THE BEST FOR MEASURABLE PCPN.
GIVEN CURRENT PCPN MVMNT...AND THE HRRR/LAV PROJECTION FEEL THE
MRNG HRS HV THE BETTER CHC - HRRR IMPLIES THE PCPN BRKG UP THIS
AFTN. REGARDLESS SKIES WL BE CLDY TDA W/ ONLY VERY LOW QPF AMTS.
HIGH TEMPS GNRLY IN M60S XCPT COOLER IN THE HIGHLANDS.
&&
.SHORT TERM /TONIGHT/...
CLDY SKIES XPCTD TO CONT TNGT FM THE FLOW OFF THE OCEAN DUE TO THE
HIGH OVR ATLC CANADA. NOT MUCH OF A DIURNAL TEMP SPREAD - LOWS IN
THE LML50S XCPT 40S IN THE HIGHLANDS. PCPN WOULD BE LGT AND
SPOTTY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY BEFORE
MOVING OUT TO SEA TUESDAY NIGHT. A COLD FRONT WILL MOVE THROUGH
PENNSYLVANIA TUESDAY BEFORE MOVING INTO NORTHERN MARYLAND LATE
TUESDAY NIGHT.
AN ONSHORE FLOW AROUND THE SURFACE HIGH WILL CAUSE LOW CLOUDS ALONG
WITH OCCASIONAL DRIZZLE TUESDAY MORNING. THE BEST CHANCE FOR DRIZZLE
WILL BE NORTH AND WEST OF THE I-95 CORRIDOR WHERE THE SUBSIDENCE
INVERSION WILL BE HIGHER. A STRENGTHENING PRESSURE GRADIENT BETWEEN
THE APPROACHING COLD FRONT AND THE DEPARTING HIGH SHOULD CAUSE
ENOUGH OF A GRADIENT TO MIX OUT THE MARINE LAYER TUESDAY AFTERNOON.
THERE SHOULD BE ENOUGH BREAKS OF SUNSHINE FOR MAX TEMPS TO REACH THE
70S ACROSS MOST LOCATIONS. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...WHERE THE
SUBSIDENCE INVERSION WILL BE WEAKEST.
THE COLD FRONT WILL CONTINUE TO DROP SOUTH THROUGH PENNSYLVANIA
TUESDAY EVENING BEFORE MOVING INTO NORTHERN MARYLAND OVERNIGHT. WARM
CONDITIONS ARE EXPECTED AHEAD OF THE BOUNDARY AND SHOWERS ARE
POSSIBLE ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE CWA. MIN
TEMPS WILL RANGE FROM THE MIDDLE 50S IN NORTHERN MARYLAND AND THE
POTOMAC HIGHLANDS TO THE LOWER 60S IN DOWNTOWN WASHINGTON AND
BALTIMORE.
THE COLD FRONT WILL STALL OUT OVER THE REGION WEDNESDAY INTO
THURSDAY BEFORE MOVING NORTH AS A WARM FRONT LATER THURSDAY AND
THURSDAY NIGHT. THE EXACT POSITION OF THE BOUNDARY REMAINS UNCERTAIN
AT THIS TIME WHICH MEANS THAT THERE IS A LOW CERTAINTY IN THE
FORECAST. THE BOUNDARY WILL SEPARATE COOL MARINE AIR TO THE NORTH
AND EAST FROM A WARM AND MOIST AIRMASS TO THE SOUTH AND WEST.
SHOWERS AND T-STORMS ARE POSSIBLE ALONG AND AHEAD OF THE
BOUNDARY...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS EACH
DAY.
A STRONGER COLD FRONT WILL APPROACH THE AREA FRIDAY BEFORE MOVING
THROUGH FRIDAY NIGHT. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG AND AHEAD OF THIS BOUNDARY. THUNDERSTORMS WILL HAVE
THE POTENTIAL TO PRODUCE GUSTY WINDS. CANADIAN HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
LOW CLOUDS ALONG WITH OCCASIONAL DRIZZLE WILL IMPACT THE TERMINALS
TUESDAY MORNING. IFR CONDITIONS ARE EXPECTED. CIGS/VSBYS WILL
IMPROVE TUESDAY AFTERNOON. A COLD FRONT WILL APPROACH THE TERMINALS
TUESDAY NIGHT BEFORE STALLING OVERHEAD WEDNESDAY INTO THURSDAY.
SHOWERS AND T-STORMS ARE POSSIBLE WEDNESDAY AND THURSDAY. A STRONGER
COLD FRONT WILL APPROACH THE TERMINALS LATER FRIDAY AND FRIDAY
NIGHT. WIDESPREAD SHOWERS/THUNDERSTORMS ARE POSSIBLE. SOME
THUNDERSTORMS MAY CONTAIN GUSTY WINDS.
&&
.MARINE...
MARGINAL SCA IN EFFECT FOR THE AFTN HRS TDA.
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY WHILE A
COLD FRONT APPROACHES FROM PENNSYLVANIA. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE WATERS TUESDAY AND THE SMALL CRAFT ADVISORY MAY BE
NEEDED FOR PORTIONS OF THE WATERS TUESDAY NIGHT. THE COLD FRONT WILL
STALL OVER THE WATERS WEDNESDAY INTO THURSDAY. A STRONGER COLD FRONT
WILL APPROACH THE WATERS FRIDAY BEFORE PASSING THROUGH FRIDAY NIGHT.
SHOWERS AND T-STORMS AHEAD OF THIS BOUNDARY MAY BECOME MORE
WIDESPREAD AND GUSTY WINDS ARE POSSIBLE IN ANY THUNDERSTORMS THAT
DEVELOP.
&&
.TIDES/COASTAL FLOODING...
AT THE MOMENT WATER LVLS IN THE BAY ARE SLTLY ABV NRML...BUT NOT
HIGH ENOUGH TO WARRANT AN ADVSRY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT TUESDAY FOR
ANZ530>543.
&&
$$
PRODUCTS...WOODY!/BAJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
111 AM EDT MON APR 15 2013
.UPDATE...
ISSUED AT 1046 PM EDT SUN APR 14 2013
TRANSITION FROM SNOW TO SLEET/FZRA IS PROGRESSING FAIRLY CLOSE TO
EXPECTATIONS. HOWEVER...TEMPS ARE NOT RISING ACROSS UPPER MI AND
EVEN INTO NRN WI UNDER STEADY EASTERLY WINDS. AS A RESULT...FZRA IS
LIKELY TO BECOME MORE OF A PROBLEM. ON ROADWAYS THAT HAVE SEEN A
COUPLE OF INCHES OF WET/SLUSHY SNOW ACCUMULATION...FZRA MAY NOT ADD
MUCH ADDITIONAL HAZARD TO THE ALREADY VERY HAZARDOUS SLOP ON THE
ROADS. HOWEVER...ELEVATED SURFACES (CARS/TREES/POWER LINES) MAY GET
A COUPLE OF TENTHS OF ICE COATING. WITH GUSTY WINDS...WEAKENED TREE
LIMBS COULD BREAK...AND THERE MAY BE SOME POWER OUTAGES. OVER THE
FAR NW...KEWEENAW IN PARTICULAR...SNOWFALL RATES WILL LIKELY SUPPORT
ADVY HEADLINE EVEN WITHOUT THE ADDITIONAL ISSUE OF SLEET/FZRA THAT
WILL OCCUR FOR A FEW HRS LATER IN THE NIGHT. SO ADVYS HAVE BEEN
POSTED FOR DICKINSON/MARQUETTE COUNTIES WESTWARD WHERE PCPN HAS BEEN
OCCURRING THIS EVENING. ADVYS WILL EXPIRE AT 06Z EXCEPT KEWEENAW
(09Z) WITH EXPECTATION OF SFC TEMPS WARMING SUFFICIENTLY TO GET
ABOVE FREEZING. NOT MUCH PCPN HAS BEEN OCCURRING OVER THE
SCNTRL/E...BUT EXPECT A PERIOD OF RAIN TO SWEEP ACROSS THAT AREA
OVERNIGHT PER RADAR IMAGERY AND MODEL FCSTS.
&&
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 428 PM EDT SUN APR 14 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOWLY RETREATING
CLOSED LO OVER SE CANADA GIVING WAY TO SHRTWV RDGING INTO THE GREAT
LKS. WITH SFC RDG AXIS/LLVL DRY AIR SHOWN ON THE 12Z GRB RAOB UNDER
THE UPR RDGING /H925-85 DEWPTS DOWN TO -12 TO -13C/...QUIET WX IS
CURRENTLY IN PLACE OVER UPR MI. BUT MID/HI CLDS IN ADVANCE OF POTENT
NEGATIVELY TILTED SHRTWV FOLLOWING THIS RDG INTO THE NRN PLAINS ARE
SPREADING INTO THE UPR LKS. 00Z-12Z H3 HGT FALLS WERE UP TO 150M
OVER THE NRN ROCKIES/PLAINS IN ADVANCE OF THIS DISTURBANCE. LEADING
EDGE OF BAND OF WAD PCPN THAT CORRESPONDS BEST WITH SHARPER PRES
GRADIENT/ ISENTROPIC ASCENT SHOWN ON THE 290-295K ISENTROPIC SFCS
/H85-75/ IS ADVANCING NEWD THRU WI AND HAS REACHED MNM THIS AFTN.
PCPN WAS FALLING AS SN AT THE LEADING EDGE OF THIS PCPN BAND...BUT
HAS CHANGED TO FZRA/RA ON THE SRN EDGE. THE BAND IS THINNEST OVER
THE E HALF OF WI...AND PCPN HAS ENDED S OF GRB. THERE WERE ALSO
SOME TS THIS MRNG AS FAR N AS IOWA NEAR H85 WARM FNT AND AT NOSE OF
65KT H85 SW LLJ SHOWN S OF THE WARM FNT AT TOPEKA KS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN TIMING/TRENDS AND
PTYPE AS WELL AS QPF.
LATE THIS AFTN...SLOWED DOWN FCST ARRIVAL OF PCPN TO ACCOUNT FOR
DRYNESS OF AIRMASS IN THE UPR GRT LKS AS WELL AS LOCATION OF BETTER
ISENTROPIC ASCENT SO FAR TO THE S. BUT ARRIVAL OF SHARPER PRES
GRADIENT/LIFT SHOWN ON THE NAM FCST 290-295K ISENTROPIC SFCS SUGGEST
PCPN WL BEGIN IN MNM COUNTY BY 21Z. FCST SDNGS/SFC OBS TO THE S SUG
BULK OF PCPN AT THE PCPN ONSET WL FALL AS SN BEFORE MIXING WITH
SLEET AND PSBLY RA OVER THE FAR S AT MNM AS ELEVATED WRMG PUSHES
TEMPS IN THE H8-75 LYR ABV ZERO. THERE COULD BE SOME SN ACCUMS UP TO
AN INCH NEAR THE WI BORDER OVER THE HIER TERRAIN W OF IMT.
TNGT...POTENT NEGATIVELY TILTED SHRTWV/SFC LO OVER SDAKOTA AT 00Z IS
FCST TO LIFT NE INTO NCENTRAL MN BY 12Z MON AND BECOME CUTOFF.
SHARPER H85-7 FGEN/MSTR CNVGC ASSOCIATED WITH H85 SE WINDS INCRSG UP
TO 50KTS BY 00Z AHEAD OF WARM FNT AS WELL AS MOST IMPRESSIVE H7 UVV
UNDER SHARPER DEEP LYR QVECTOR CNVGC OVER THE W CLOSER TO APRCHG
SHRTWV WARRANTS HIER POPS OVER THE W THIS EVNG...WITH A MORE NARROW
BAND OF LIGHTER PCPN PASSING THRU THE ERN ZNS AS SHOWN BY HIER RES
MODELS. AS THE SHRTWV SHIFTS FARTHER E AND ACCOMPANYING WARM
CONVEYOR BELT MSTR RIBBON UNDER IMPRESSIVE UPR DVGC AHEAD OF H3 JET
MAX SHIFTING ARND THE SRN FLANK OF THE CLOSED LO IN MN SHIFTS TO THE
E...HIER POPS WL ARRIVE OVER THE E AS WELL AFT 06Z AT NOSE OF
VEERING H85 WINDS TO S AND INCRSG TO 60KTS LIFTING PWAT 0.75 INCH TO
1 INCH...OR ALMOST 200 PCT OF NORMAL. THESE VIGOROUS DYNAMICS/
MOISTENING JUSTIFY QPF NEAR 1 INCH OVER THE W HALF...BUT THERE WL BE
LOWER TOTALS OVER THE E HALF BECAUSE THE WARM CONVEYOR BELT MSTR WL
MOVE STEADILY TO THE E AND LIMIT RESIDENCE TIME OF ANY HEAVIER RA.
RUNOFF FM THE HEAVY RA OVER THE W HALF IN THE PRESENCE OF LINGERING
SN PILES MAY CAUSE SOME PONDING OF WATER. MAINTAINED MENTION OF
ELEVATED TS OVER THE SE AT THE NOSE OF THIS LLJ AND WHERE H875 TEMPS
TO THE N OF SFC WARM FNT ARE PROGGED TO RISE NEAR 10C. ARRIVAL OF
VIGOROUS DRY SLOTTING IN THE JET SURGE WL DIMINISH THE PCPN LATE
TNGT SW TO NE...WITH BACK EDGE OF WARM CONVEYOR BELT MSTR NEARING
ERY-MSQ TOWARD 12Z. IN FACT...FCST SDNGS INDICATE THERE MAY BE SOME
CLRG OVER THE SW LATE WITH VIGOROUS LLVL DRYING.
MAIN FCST CONCERNS TNGT ARE FOCUSED ON PTYPE AND POTENTIAL SN/ICE
ACCUMS. WITH THE VIGOROUS WAD...FCST SDNGS SHOW EXPANDING ELEVATED
WARM LYR ARRIVING S TO N...SO SN AT ONSET OF PCPN WL CHG TO RA. BEST
CHC FOR SEVERAL INCHES OF WET SNOW WL BE OVER THE HIER TERRAIN OF
THE KEWEENAW WHERE THE WARM AIR WL ARRIVE LATEST AND TEMPS STAYED A
BIT LOWER TDAY IN THE PRESENCE OF UPSLOPE COOLING OFF THE CHILLY
WATERS OF LK SUP. THERE WL BE SOME SLEET AS WELL AS EVAPORATIVE
COOLING ASSOCIATED WITH DRY AIR SHOWN ON THE 12Z GRB RAOB MAINTAINS
SUFFICIENTLY COLD TEMPS IN THE LYR BLO THE ELEVATED WARM NOSE FOR RA
DROPS TO REFREEZE INTO ICE PELLETS. BUT AS THIS LYR SATURATES AND
WARMS...SLEET SHOULD END AND GIVE WAY TO ONLY RA AS SFC TEMPS SLOWLY
RISE THRU THE 30S. THE BIG QUESTION IS HOW LONG SFC TEMPS WL BE NEAR
32 TO ALLOW FOR FZRA. EXPLICIT MODEL FCST SNDGS HAVE INDICATED FOR
SOME TIME THAT A PERIOD OF FZRA WL OCCUR. ATLHOUGH THE TIME OF YEAR
SHOULD RULE OUT FZRA AND SFC TEMPS HAVE RISEN WELL ABV 32 AT MOST
SPOTS THIS AFTN...LINGERING LO DEWPTS/POTENTIAL FOR EVAPORATE
COOLING AS WELL AS THE FCST SDNGS INDICATE THIS THREAT MIGHT BE REAL
MAINLY OVER THE HIER TERRAIN W OF MQT-IMT. THE NAM SHOWS LINGERING
AXIS OF LOWER DEWPTS IN THE H925 LYR IN THE ELY SFC FLOW N OF WARM
FNT. OPTED TO INCLUDE A MENTION OF FZRA THIS EVNG INTO THE EARLY
OVERNGT OVER THE HIER TERRAIN OF THE NW WHERE UPSLOPE COOLING WL
KEEP TEMPS AT LEAST CLOSE TO 32 AFTER SUNSET.
CONSIDERING THE POTENTIAL FOR SOME LOCALLY HVY SN...-FZRA...AND
PONDING OF WATER ACCOMPANYING HEAVIER RA...OPTED TO ISSUE AN SPS FOR
THE W HALF OF THE CWA TO HIGHLIGHT THESE POSSIBLE HAZARDS.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 428 PM EDT SUN APR 14 2013
BY MON MORNING...THE STACKED LOW WILL BE OVER NRN MN...WITH THE
ASSOCIATED OCCLUDED FRONT NE OF THE CWA...ALLOWING THE DRY SLOT TO
QUICKLY COVER MUCH OF THE CWA BY MID MORNING. THE EXCEPTION TO THIS
WILL BE OVER THE WRN THIRD OF THE U.P. WHERE WRAP AROUND LOW LEVEL
MOISTURE WILL MOVE IN. MODELS HAVE BEEN TRENDING SLIGHTLY FARTHER E
WITH THE SFC LOW AS IT MOVES ACROSS THE MN ARROWHEAD AND FAR NRN
LAKE SUPERIOR...SO THE LOW LEVEL MOISTURE COVERAGE HAS ALSO BEEN
TRENDING FARTHER E. THE IMPACT OF THE LOW LEVEL MOISTURE WILL BE TO
ALLOW CONVECTIVE RAIN/SNOW SHOWERS DUE TO THE COLD AIR OVERHEAD IN
PROXIMITY TO THE UPPER LOW AND STEEP LOW LEVEL LAPSE RATES. WITH
MOST MODELS SHOWING A COUPLE HUNDREDTHS OF AN INCH OF QPF OVER THE
WRN THIRD OF UPPER MI...THINK CHANCE POPS FROM PREVIOUS SHIFT COVERS
IT WELL. THE GOOD LOW LEVEL MIXING WILL ALSO ALLOW FOR MIXING OF
GUSTY WINDS TO THE SFC. THINK THAT MIXING TO AROUND 800MB AS SHOWN
BY MODEL SOUNDINGS SEEMS REALISTIC...AND WITH 800MB WINDS MON OF
AROUND 45KTS...COULD SEE SOME 40-45MPH GUSTS. EVEN THOUGH THE SYSTEM
IS WEAKENING...PRESSURE RISE/FALL COUPLET ORIENTATION WILL ENHANCE
THE GEOSTROPHIC WIND COMPONENT. DO NOT THINK CONDITIONS WARRANT WIND
ADVISORY...BUT WILL BE BORDERLINE. ANOTHER FACTOR WITH THE GOOD
MIXING IS THAT SFC TEMPS WILL BE ABLE TO WARM CONSIDERABLY...AND
SHOULD REACH AT LEAST 40 EVERYWHERE...BUT IN AREAS THAT DO NOT SEE
THE LOW LEVEL MOISTURE /SCENTRAL AND ERN U.P./ WILL GET UP TO AROUND
50. COULD SEE SOME LAKE EFFECT SNOW OVER THE FAR W ALONG AND BEHIND
THE SECONDARY COLD FRONT AS WINDS TURN NWLY...BUT COVERAGE SHOULD BE
LIMITED AT BEST.
RIDGING BUILD IN ON TUE AND TUE NIGHT...SO WILL SEE QUIET WEATHER.
GFS CONTINUES TO SHOW SOME QPF OVER THE WRN HALF OF UPPER MI
TUE...BUT GIVEN DOWNWARD MOTION WILL KEEP THE FORECAST DRY.
WED NIGHT AND THURSDAY...ATTENTION THEN TURNS TO A DEEP UPPER TROUGH
THAT WILL TRAVERSE THE MID SECTION OF THE COUNTRY FROM MID TO LATE
WEEK. THIS TROUGH RESULTS IN A SFC LOW MOVING THROUGH THE
REGION...ALTHOUGH THE EXACT TRACK REMAINS UNCERTAIN. DEFINITELY
FAVOR THE TRACK GIVEN BY THE ECMWF WHICH HAS MUCH BETTER CONTINUITY
IN BRINGING THE SFC LOW FROM NRN IL AT 06Z THU TO NEAR TRAVERSE CITY
MI BY 12Z THU THEN TO LAKE HURON BY 18Z THU. THE ECMWF HAS BEEN
TRENDING EVER SO SLIGHTLY WESTWARD WITH THE LOW TRACK...BUT NOT
NEARLY AS MUCH AS THE GFS AND GEM WHICH HAVE SHOWN POOR RUN TO RUN
CONTINUITY AND NOW WITH THE LATEST RUNS ARE CLOSER TO THE ECMWF
SOLUTION. WITH THE ECMWF SOLUTION...AREAS NEAR LAKE MI AND OVER THE
ERN CWA WOULD BE FAVORED FOR MOSTLY RAIN...WITH THE DRY SLOT MOVING
IN BEFORE THE COLDER AIR CAN TURN THINGS TO SNOW. IN NCENTRAL AND
WRN UPPER MI...TEMPERATURES AND LOW TRACK WILL BE FAVORABLE FOR
HEAVY SNOW. IT IS IMPORTANT TO EMPHASIZE THAT THERE IS CONSIDERABLE
UNCERTAINTY WITH THE TRACK OF THIS SYSTEM...WITH A WIDE RANGE OF
PRECIPITATION POSSIBILITIES DEPENDING ON THE TRACK...RANGING FROM HEAVY
SNOW TO MOSTLY RAIN AND WARMER TEMPERATURES OVER THE DEEP SNOWPACK
ACROSS THE AREA. WHATEVER SCENARIO PLAYS OUT...IT BEARS CLOSELY
WATCHING THIS SYSTEM OVER THE NEXT FEW DAYS. WILL CONTINUE TO
MENTION THE POTENTIAL FOR HEAVY SNOW IN THE HAZARDOUS WEATHER
OUTLOOK.
REGARDLESS OF THE EXACT TRACK...850MB TEMPS DROP TO -10 TO -14C PER
THE GFS AND ECMWF BY 18Z FRI WHICH COMBINED WITH THE UPPER TROUGH AND
N-NW FLOW SHOULD BE ENOUGH FOR AT LEAST SOME LAKE ENHANCED SNOW
FRIDAY INTO SATURDAY MORNING. THIS WILL ALSO ALLOW FOR TEMPS TO BE
WELL BELOW NORMAL ONCE AGAIN WITH TEMPS LIKELY STRUGGLING TO REACH
THE MID 30S SATURDAY. LOTS OF UNCERTAINTY NEXT SUN GIVEN MODEL
DISAGREEMENT AND RUN TO RUN DISCONTINUITY...SO WILL JUST USE A
CONSENSUS OF GUIDANCE AND FOCUS ON SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 111 AM EDT MON APR 15 2013
PCPN ASSOCIATED WITH LOW PRES TRACKING NE THRU MN WILL END FROM SW
TO NE LATE IN THE NIGHT. WHILE TEMPS HAVE WARMED ENOUGH FOR PTYPE
TO BE JUST -RA AT KIWD/KSAW...KCMX MAY SEE ANOTHER COUPLE OF HRS OF
FZRASNPL BEFORE IT CHANGES TO RA. DOWNSLOPING E/SE WIND SHOULD HELP
KEEP CONDITIONS NO LWR THAN MVFR AT KIWD. MEANWHILE...UPSLOPE E TO
SE WINDS WILL LIKELY RESULT IN LIFR CONDITIONS CONTINUING AT KCMX
AND LATER AT KSAW. ALTHOUGH LOW-LEVEL JET OF 50-60KT AT 2-5KFT WILL
BE SHIFTING ACROSS THE AREA OVERNIGHT...DID NOT INCLUDE LLWS SINCE
GUSTY SFC WINDS ARE EXPECTED. DRY SLOT WORKING THRU THE AREA IN THE
MORNING SHOULD BRING RAPID IMPROVEMENT TO VFR AT ALL 3 SITES WITH
CLOUDS LIKELY SCATTERING OUT FOR A TIME. THEN...MOISTURE WRAPPING
AROUND SFC LOW LIFTING THRU NRN MN INTO ONTARIO WILL PROBABLY BRING
MVFR CIGS BACK TO KIWD/KCMX DURING THE DAY TODAY. MIGHT BE A FEW
-SHRASN AS WELL...BUT CONFIDENCE IS LOW AND SO NOT WORTH A MENTION
AT THIS TIME. GUSTY SW WINDS ARE EXPECTED TODAY AS THE SFC LOW LIFTS
BY TO THE NW OF THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT SUN APR 14 2013
EXPECT ENE WINDS TO 25 TO 30 KTS TO INCREASE TO GALES TO 35 KTS OVER
MUCH OF THE LAKE TONIGHT AND VEER SE AS VIGOROUS LO PRES NOW IN THE
NORTHERN PLAINS MOVES THRU MINNESOTA AND THE PRES GRADIENT TIGHTENS
SHARPLY. THE STRONGEST WINDS WL OCCUR IN AREAS WHERE TOPOGRAPHY
ENHANCES THE E TO SE WINDS. LATER TONIGHT...WINDS OVER THE W HALF
WILL DIMINISH WITH THE CLOSER APPROACH OF THE LOW AND A WEAKER PRES
GRADIENT. MAINTAINED GALE WARNINGS ISSUED EARLIER FOR LATE TODAY
THRU TONIGHT.
AS THE LOW PRESSURE SYSTEM MOVES FROM NORTHERN MN MONDAY MORNING TO
JAMES BY BY TUESDAY MORNING...STRONG SOUTHWEST WINDS MAY GUST TO 35
KNOTS OVER THE WESTERN HALF OF LAKE SUPERIOR MONDAY INTO MONDAY
NIGHT. WINDS THEN DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING
OUT OF THE N WEDNESDAY NIGHT INTO FRIDAY WHEN GALES MAY BE POSSIBLE
AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
MIZ001-003.
FREEZING RAIN ADVISORY UNTIL 1 AM CDT EARLY THIS MORNING FOR
MIZ010-011.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ EARLY THIS
MORNING FOR MIZ002-004-005-009-084.
LAKE SUPERIOR...
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ266-267.
GALE WARNING UNTIL 4 AM EDT /3 AM CDT/ EARLY THIS MORNING FOR
LSZ162-263.
GALE WARNING UNTIL 5 AM EDT EARLY THIS MORNING FOR LSZ244>246-
264-265.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...07
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1046 PM EDT SUN APR 14 2013
.UPDATE...
ISSUED AT 1046 PM EDT SUN APR 14 2013
TRANSITION FROM SNOW TO SLEET/FZRA IS PROGRESSING FAIRLY CLOSE TO
EXPECTATIONS. HOWEVER...TEMPS ARE NOT RISING ACROSS UPPER MI AND
EVEN INTO NRN WI UNDER STEADY EASTERLY WINDS. AS A RESULT...FZRA IS
LIKELY TO BECOME MORE OF A PROBLEM. ON ROADWAYS THAT HAVE SEEN A
COUPLE OF INCHES OF WET/SLUSHY SNOW ACCUMULATION...FZRA MAY NOT ADD
MUCH ADDITIONAL HAZARD TO THE ALREADY VERY HAZARDOUS SLOP ON THE
ROADS. HOWEVER...ELEVATED SURFACES (CARS/TREES/POWER LINES) MAY GET
A COUPLE OF TENTHS OF ICE COATING. WITH GUSTY WINDS...WEAKENED TREE
LIMBS COULD BREAK...AND THERE MAY BE SOME POWER OUTAGES. OVER THE
FAR NW...KEWEENAW IN PARTICULAR...SNOWFALL RATES WILL LIKELY SUPPORT
ADVY HEADLINE EVEN WITHOUT THE ADDITIONAL ISSUE OF SLEET/FZRA THAT
WILL OCCUR FOR A FEW HRS LATER IN THE NIGHT. SO ADVYS HAVE BEEN
POSTED FOR DICKINSON/MARQUETTE COUNTIES WESTWARD WHERE PCPN HAS BEEN
OCCURRING THIS EVENING. ADVYS WILL EXPIRE AT 06Z EXCEPT KEWEENAW
(09Z) WITH EXPECTATION OF SFC TEMPS WARMING SUFFICIENTLY TO GET
ABOVE FREEZING. NOT MUCH PCPN HAS BEEN OCCURRING OVER THE
SCNTRL/E...BUT EXPECT A PERIOD OF RAIN TO SWEEP ACROSS THAT AREA
OVERNIGHT PER RADAR IMAGERY AND MODEL FCSTS.
&&
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 428 PM EDT SUN APR 14 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOWLY RETREATING
CLOSED LO OVER SE CANADA GIVING WAY TO SHRTWV RDGING INTO THE GREAT
LKS. WITH SFC RDG AXIS/LLVL DRY AIR SHOWN ON THE 12Z GRB RAOB UNDER
THE UPR RDGING /H925-85 DEWPTS DOWN TO -12 TO -13C/...QUIET WX IS
CURRENTLY IN PLACE OVER UPR MI. BUT MID/HI CLDS IN ADVANCE OF POTENT
NEGATIVELY TILTED SHRTWV FOLLOWING THIS RDG INTO THE NRN PLAINS ARE
SPREADING INTO THE UPR LKS. 00Z-12Z H3 HGT FALLS WERE UP TO 150M
OVER THE NRN ROCKIES/PLAINS IN ADVANCE OF THIS DISTURBANCE. LEADING
EDGE OF BAND OF WAD PCPN THAT CORRESPONDS BEST WITH SHARPER PRES
GRADIENT/ ISENTROPIC ASCENT SHOWN ON THE 290-295K ISENTROPIC SFCS
/H85-75/ IS ADVANCING NEWD THRU WI AND HAS REACHED MNM THIS AFTN.
PCPN WAS FALLING AS SN AT THE LEADING EDGE OF THIS PCPN BAND...BUT
HAS CHANGED TO FZRA/RA ON THE SRN EDGE. THE BAND IS THINNEST OVER
THE E HALF OF WI...AND PCPN HAS ENDED S OF GRB. THERE WERE ALSO
SOME TS THIS MRNG AS FAR N AS IOWA NEAR H85 WARM FNT AND AT NOSE OF
65KT H85 SW LLJ SHOWN S OF THE WARM FNT AT TOPEKA KS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN TIMING/TRENDS AND
PTYPE AS WELL AS QPF.
LATE THIS AFTN...SLOWED DOWN FCST ARRIVAL OF PCPN TO ACCOUNT FOR
DRYNESS OF AIRMASS IN THE UPR GRT LKS AS WELL AS LOCATION OF BETTER
ISENTROPIC ASCENT SO FAR TO THE S. BUT ARRIVAL OF SHARPER PRES
GRADIENT/LIFT SHOWN ON THE NAM FCST 290-295K ISENTROPIC SFCS SUGGEST
PCPN WL BEGIN IN MNM COUNTY BY 21Z. FCST SDNGS/SFC OBS TO THE S SUG
BULK OF PCPN AT THE PCPN ONSET WL FALL AS SN BEFORE MIXING WITH
SLEET AND PSBLY RA OVER THE FAR S AT MNM AS ELEVATED WRMG PUSHES
TEMPS IN THE H8-75 LYR ABV ZERO. THERE COULD BE SOME SN ACCUMS UP TO
AN INCH NEAR THE WI BORDER OVER THE HIER TERRAIN W OF IMT.
TNGT...POTENT NEGATIVELY TILTED SHRTWV/SFC LO OVER SDAKOTA AT 00Z IS
FCST TO LIFT NE INTO NCENTRAL MN BY 12Z MON AND BECOME CUTOFF.
SHARPER H85-7 FGEN/MSTR CNVGC ASSOCIATED WITH H85 SE WINDS INCRSG UP
TO 50KTS BY 00Z AHEAD OF WARM FNT AS WELL AS MOST IMPRESSIVE H7 UVV
UNDER SHARPER DEEP LYR QVECTOR CNVGC OVER THE W CLOSER TO APRCHG
SHRTWV WARRANTS HIER POPS OVER THE W THIS EVNG...WITH A MORE NARROW
BAND OF LIGHTER PCPN PASSING THRU THE ERN ZNS AS SHOWN BY HIER RES
MODELS. AS THE SHRTWV SHIFTS FARTHER E AND ACCOMPANYING WARM
CONVEYOR BELT MSTR RIBBON UNDER IMPRESSIVE UPR DVGC AHEAD OF H3 JET
MAX SHIFTING ARND THE SRN FLANK OF THE CLOSED LO IN MN SHIFTS TO THE
E...HIER POPS WL ARRIVE OVER THE E AS WELL AFT 06Z AT NOSE OF
VEERING H85 WINDS TO S AND INCRSG TO 60KTS LIFTING PWAT 0.75 INCH TO
1 INCH...OR ALMOST 200 PCT OF NORMAL. THESE VIGOROUS DYNAMICS/
MOISTENING JUSTIFY QPF NEAR 1 INCH OVER THE W HALF...BUT THERE WL BE
LOWER TOTALS OVER THE E HALF BECAUSE THE WARM CONVEYOR BELT MSTR WL
MOVE STEADILY TO THE E AND LIMIT RESIDENCE TIME OF ANY HEAVIER RA.
RUNOFF FM THE HEAVY RA OVER THE W HALF IN THE PRESENCE OF LINGERING
SN PILES MAY CAUSE SOME PONDING OF WATER. MAINTAINED MENTION OF
ELEVATED TS OVER THE SE AT THE NOSE OF THIS LLJ AND WHERE H875 TEMPS
TO THE N OF SFC WARM FNT ARE PROGGED TO RISE NEAR 10C. ARRIVAL OF
VIGOROUS DRY SLOTTING IN THE JET SURGE WL DIMINISH THE PCPN LATE
TNGT SW TO NE...WITH BACK EDGE OF WARM CONVEYOR BELT MSTR NEARING
ERY-MSQ TOWARD 12Z. IN FACT...FCST SDNGS INDICATE THERE MAY BE SOME
CLRG OVER THE SW LATE WITH VIGOROUS LLVL DRYING.
MAIN FCST CONCERNS TNGT ARE FOCUSED ON PTYPE AND POTENTIAL SN/ICE
ACCUMS. WITH THE VIGOROUS WAD...FCST SDNGS SHOW EXPANDING ELEVATED
WARM LYR ARRIVING S TO N...SO SN AT ONSET OF PCPN WL CHG TO RA. BEST
CHC FOR SEVERAL INCHES OF WET SNOW WL BE OVER THE HIER TERRAIN OF
THE KEWEENAW WHERE THE WARM AIR WL ARRIVE LATEST AND TEMPS STAYED A
BIT LOWER TDAY IN THE PRESENCE OF UPSLOPE COOLING OFF THE CHILLY
WATERS OF LK SUP. THERE WL BE SOME SLEET AS WELL AS EVAPORATIVE
COOLING ASSOCIATED WITH DRY AIR SHOWN ON THE 12Z GRB RAOB MAINTAINS
SUFFICIENTLY COLD TEMPS IN THE LYR BLO THE ELEVATED WARM NOSE FOR RA
DROPS TO REFREEZE INTO ICE PELLETS. BUT AS THIS LYR SATURATES AND
WARMS...SLEET SHOULD END AND GIVE WAY TO ONLY RA AS SFC TEMPS SLOWLY
RISE THRU THE 30S. THE BIG QUESTION IS HOW LONG SFC TEMPS WL BE NEAR
32 TO ALLOW FOR FZRA. EXPLICIT MODEL FCST SNDGS HAVE INDICATED FOR
SOME TIME THAT A PERIOD OF FZRA WL OCCUR. ATLHOUGH THE TIME OF YEAR
SHOULD RULE OUT FZRA AND SFC TEMPS HAVE RISEN WELL ABV 32 AT MOST
SPOTS THIS AFTN...LINGERING LO DEWPTS/POTENTIAL FOR EVAPORATE
COOLING AS WELL AS THE FCST SDNGS INDICATE THIS THREAT MIGHT BE REAL
MAINLY OVER THE HIER TERRAIN W OF MQT-IMT. THE NAM SHOWS LINGERING
AXIS OF LOWER DEWPTS IN THE H925 LYR IN THE ELY SFC FLOW N OF WARM
FNT. OPTED TO INCLUDE A MENTION OF FZRA THIS EVNG INTO THE EARLY
OVERNGT OVER THE HIER TERRAIN OF THE NW WHERE UPSLOPE COOLING WL
KEEP TEMPS AT LEAST CLOSE TO 32 AFTER SUNSET.
CONSIDERING THE POTENTIAL FOR SOME LOCALLY HVY SN...-FZRA...AND
PONDING OF WATER ACCOMPANYING HEAVIER RA...OPTED TO ISSUE AN SPS FOR
THE W HALF OF THE CWA TO HIGHLIGHT THESE POSSIBLE HAZARDS.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 428 PM EDT SUN APR 14 2013
BY MON MORNING...THE STACKED LOW WILL BE OVER NRN MN...WITH THE
ASSOCIATED OCCLUDED FRONT NE OF THE CWA...ALLOWING THE DRY SLOT TO
QUICKLY COVER MUCH OF THE CWA BY MID MORNING. THE EXCEPTION TO THIS
WILL BE OVER THE WRN THIRD OF THE U.P. WHERE WRAP AROUND LOW LEVEL
MOISTURE WILL MOVE IN. MODELS HAVE BEEN TRENDING SLIGHTLY FARTHER E
WITH THE SFC LOW AS IT MOVES ACROSS THE MN ARROWHEAD AND FAR NRN
LAKE SUPERIOR...SO THE LOW LEVEL MOISTURE COVERAGE HAS ALSO BEEN
TRENDING FARTHER E. THE IMPACT OF THE LOW LEVEL MOISTURE WILL BE TO
ALLOW CONVECTIVE RAIN/SNOW SHOWERS DUE TO THE COLD AIR OVERHEAD IN
PROXIMITY TO THE UPPER LOW AND STEEP LOW LEVEL LAPSE RATES. WITH
MOST MODELS SHOWING A COUPLE HUNDREDTHS OF AN INCH OF QPF OVER THE
WRN THIRD OF UPPER MI...THINK CHANCE POPS FROM PREVIOUS SHIFT COVERS
IT WELL. THE GOOD LOW LEVEL MIXING WILL ALSO ALLOW FOR MIXING OF
GUSTY WINDS TO THE SFC. THINK THAT MIXING TO AROUND 800MB AS SHOWN
BY MODEL SOUNDINGS SEEMS REALISTIC...AND WITH 800MB WINDS MON OF
AROUND 45KTS...COULD SEE SOME 40-45MPH GUSTS. EVEN THOUGH THE SYSTEM
IS WEAKENING...PRESSURE RISE/FALL COUPLET ORIENTATION WILL ENHANCE
THE GEOSTROPHIC WIND COMPONENT. DO NOT THINK CONDITIONS WARRANT WIND
ADVISORY...BUT WILL BE BORDERLINE. ANOTHER FACTOR WITH THE GOOD
MIXING IS THAT SFC TEMPS WILL BE ABLE TO WARM CONSIDERABLY...AND
SHOULD REACH AT LEAST 40 EVERYWHERE...BUT IN AREAS THAT DO NOT SEE
THE LOW LEVEL MOISTURE /SCENTRAL AND ERN U.P./ WILL GET UP TO AROUND
50. COULD SEE SOME LAKE EFFECT SNOW OVER THE FAR W ALONG AND BEHIND
THE SECONDARY COLD FRONT AS WINDS TURN NWLY...BUT COVERAGE SHOULD BE
LIMITED AT BEST.
RIDGING BUILD IN ON TUE AND TUE NIGHT...SO WILL SEE QUIET WEATHER.
GFS CONTINUES TO SHOW SOME QPF OVER THE WRN HALF OF UPPER MI
TUE...BUT GIVEN DOWNWARD MOTION WILL KEEP THE FORECAST DRY.
WED NIGHT AND THURSDAY...ATTENTION THEN TURNS TO A DEEP UPPER TROUGH
THAT WILL TRAVERSE THE MID SECTION OF THE COUNTRY FROM MID TO LATE
WEEK. THIS TROUGH RESULTS IN A SFC LOW MOVING THROUGH THE
REGION...ALTHOUGH THE EXACT TRACK REMAINS UNCERTAIN. DEFINITELY
FAVOR THE TRACK GIVEN BY THE ECMWF WHICH HAS MUCH BETTER CONTINUITY
IN BRINGING THE SFC LOW FROM NRN IL AT 06Z THU TO NEAR TRAVERSE CITY
MI BY 12Z THU THEN TO LAKE HURON BY 18Z THU. THE ECMWF HAS BEEN
TRENDING EVER SO SLIGHTLY WESTWARD WITH THE LOW TRACK...BUT NOT
NEARLY AS MUCH AS THE GFS AND GEM WHICH HAVE SHOWN POOR RUN TO RUN
CONTINUITY AND NOW WITH THE LATEST RUNS ARE CLOSER TO THE ECMWF
SOLUTION. WITH THE ECMWF SOLUTION...AREAS NEAR LAKE MI AND OVER THE
ERN CWA WOULD BE FAVORED FOR MOSTLY RAIN...WITH THE DRY SLOT MOVING
IN BEFORE THE COLDER AIR CAN TURN THINGS TO SNOW. IN NCENTRAL AND
WRN UPPER MI...TEMPERATURES AND LOW TRACK WILL BE FAVORABLE FOR
HEAVY SNOW. IT IS IMPORTANT TO EMPHASIZE THAT THERE IS CONSIDERABLE
UNCERTAINTY WITH THE TRACK OF THIS SYSTEM...WITH A WIDE RANGE OF
PRECIPITATION POSSIBILITIES DEPENDING ON THE TRACK...RANGING FROM HEAVY
SNOW TO MOSTLY RAIN AND WARMER TEMPERATURES OVER THE DEEP SNOWPACK
ACROSS THE AREA. WHATEVER SCENARIO PLAYS OUT...IT BEARS CLOSELY
WATCHING THIS SYSTEM OVER THE NEXT FEW DAYS. WILL CONTINUE TO
MENTION THE POTENTIAL FOR HEAVY SNOW IN THE HAZARDOUS WEATHER
OUTLOOK.
REGARDLESS OF THE EXACT TRACK...850MB TEMPS DROP TO -10 TO -14C PER
THE GFS AND ECMWF BY 18Z FRI WHICH COMBINED WITH THE UPPER TROUGH AND
N-NW FLOW SHOULD BE ENOUGH FOR AT LEAST SOME LAKE ENHANCED SNOW
FRIDAY INTO SATURDAY MORNING. THIS WILL ALSO ALLOW FOR TEMPS TO BE
WELL BELOW NORMAL ONCE AGAIN WITH TEMPS LIKELY STRUGGLING TO REACH
THE MID 30S SATURDAY. LOTS OF UNCERTAINTY NEXT SUN GIVEN MODEL
DISAGREEMENT AND RUN TO RUN DISCONTINUITY...SO WILL JUST USE A
CONSENSUS OF GUIDANCE AND FOCUS ON SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 739 PM EDT SUN APR 14 2013
LOW PRES TRACKING NE FROM SW MN WILL BRING A PERIOD OF WINTRY
WEATHER TO KIWD/KCMX/KSAW THIS EVENING. IFR CONDITIONS SHOULD
PREVAIL THIS EVENING AT KIWD WHILE KCMX/KSAW SHOULD SEE CONDITIONS
FALL TO LIFR WITH UPSLOPING E TO SE WINDS. AS NOSE OF WARMER AIR
ALOFT SURGES N...SNOW WILL LIKELY MIX WITH SLEET/RAIN AT KIWD/KSAW
IN THE EVENING WITH CHANGE TO ALL RAIN AT THE END OF THE EVENING. AT
KCMX...COLUMN WILL REMAIN COLDER LONGER...RESULTING IN SLEET/RAIN
MIXING WITH THE SNOW LATE EVENING AND A CHANGE TO RAIN OVERNIGHT. AS
PCPN CHANGES TO RAIN...CONDITIONS WILL LIKELY IMPROVE TO LOW MVFR AT
KIWD. HOWEVER...UPSLOPE WINDS SHOULD WORK TO MAINTAIN IFR/LIFR
CONDITIONS AT KCMX/KSAW. ALTHOUGH LOW-LEVEL JET OF 50-60KT AT 2-5KFT
WILL BE SHIFTING ACROSS THE AREA TONIGHT...DID NOT INCLUDE LLWS
SINCE GUSTY SFC WINDS ARE EXPECTED. MOISTURE WRAPPING AROUND SFC LOW
LIFTING THRU NRN MN INTO ONTARIO SHOULD RESULT IN MVFR CIGS THRU THE
DAY MON AT KIWD ALONG WITH THE POTENTIAL FOR OCNL -SHRASN. DRY SLOT
WORKING THRU THE AREA E OF KIWD SHOULD RESULT IN A PERIOD OF VFR
CONDITIONS AT KCMX/KSAW IN THE MORNING. MVFR CIGS MAY RETURN TO KCMX
IN THE AFTN AS MOISTURE WRAPS BACK INTO THE AREA. GUSTY SW WINDS ARE
EXPECTED MON AS THE SFC LOW LIFTS BY TO THE NW OF THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT SUN APR 14 2013
EXPECT ENE WINDS TO 25 TO 30 KTS TO INCREASE TO GALES TO 35 KTS OVER
MUCH OF THE LAKE TONIGHT AND VEER SE AS VIGOROUS LO PRES NOW IN THE
NORTHERN PLAINS MOVES THRU MINNESOTA AND THE PRES GRADIENT TIGHTENS
SHARPLY. THE STRONGEST WINDS WL OCCUR IN AREAS WHERE TOPOGRAPHY
ENHANCES THE E TO SE WINDS. LATER TONIGHT...WINDS OVER THE W HALF
WILL DIMINISH WITH THE CLOSER APPROACH OF THE LOW AND A WEAKER PRES
GRADIENT. MAINTAINED GALE WARNINGS ISSUED EARLIER FOR LATE TODAY
THRU TONIGHT.
AS THE LOW PRESSURE SYSTEM MOVES FROM NORTHERN MN MONDAY MORNING TO
JAMES BY BY TUESDAY MORNING...STRONG SOUTHWEST WINDS MAY GUST TO 35
KNOTS OVER THE WESTERN HALF OF LAKE SUPERIOR MONDAY INTO MONDAY
NIGHT. WINDS THEN DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING
OUT OF THE N WEDNESDAY NIGHT INTO FRIDAY WHEN GALES MAY BE POSSIBLE
AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 5 AM EDT MONDAY FOR MIZ001-003.
FREEZING RAIN ADVISORY UNTIL 1 AM CDT MONDAY FOR MIZ010-011.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ MONDAY FOR
MIZ002-004-005-009-084.
LAKE SUPERIOR...
GALE WARNING UNTIL 8 AM EDT MONDAY FOR LSZ266-267.
GALE WARNING UNTIL 4 AM EDT /3 AM CDT/ MONDAY FOR LSZ162-263.
GALE WARNING UNTIL 5 AM EDT MONDAY FOR LSZ244>246-264-265.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
1243 AM CDT MON APR 15 2013
.AVIATION.../06Z TAF ISSUANCE/
WITH THE DRY SLOT MOVING THROUGH THE FA...THERE WILL BE A MIX OF
PTYPES INCLUDING SNOW/FZRA/DZ/BR/FG AND BLSN. CIGS/VSBYS WILL RUN
THE GAMUT FROM MVFR/IFR/LIFR AND BACK. THE SFC LOW WILL MOVE
NEARBY AND THE GUSTY SFC WINDS WILL SUBSIDE BEFORE INCREASING
AGAIN BY 15Z OUT OF THE WEST.
&&
.PREV DISCUSSION... /ISSUED 941 PM CDT SUN APR 14 2013/
UPDATE...DRY SLOT IS BEGINNING TO WORK ITS WAY INTO THE SW
PORTION OF THE FA PER SATELLITE IMAGERY. MOISTURE FROM THE GULF
CONTINUES TO ADVECT INTO MUCH OF THE FA WHICH HAS LED TO THE PCPN
IN NW WI CHANGING OVER TO RAIN. HOWEVER...SFC TEMPS ARE HOVERING
AROUND 32F SO WILL PERSIST IN MONITORING FOR ADDITIONAL FZRA. SFC
OBS INDICATE THE FZRA HAS ENDED IN NW WI FOR NOW. EXPECT THE DRY
SLOT TO REACH THE TWIN PORTS AROUND 530Z. THIS WILL BRING THE
GUSTY WINDS TO AN END AS SEEN IN OBS DOWNSTREAM WHERE DRY SLOT HAS
ALREADY PASSED. MADE SOME MINOR ADJUSTMENTS TO THE WIND AS A
RESULT. REST OF THE FORECAST IN THE BALLPARK INCLUDING HEADLINES.
PREV DISCUSSION... /ISSUED 730 PM CDT SUN APR 14 2013/
UPDATE...ADDED FZRA TO NW WI AS FZRA HAS BEEN REPORTED AT
HYR AND SHELL LAKE. BAND OF HIGHER REFLECTIVITIES CURRENTLY ON
RADAR HAS BEEN MOSTLY FZRA...BUT REPORTS ARE BEGINNING TO INDICATE
IT IS CHANGING OVER TO RAIN. HAVE EXTENDED THE WINTER WEATHER
ADVISORIES IN MUCH OF NORTHWEST WI THAT WERE DUE TO EXPIRE AT 00Z
TO 06Z. THIS IS TO ACCOUNT FOR THE FZRA AND THE CONTINUED WINTRY
MIX THIS EVENING. NO OTHER BIG CHANGES.
AVIATION...00Z TAFS.
A WINTRY MIXED BAG OF PCPN TYPES ARE FORECAST AS THE SFC LOW MOVES
INTO SOUTHERN MN. CIGS AND VSBYS WILL VARY WILDLY FROM MVFR TO IFR
TO LIFR AND BACK AGAIN. SNOW WILL BE THE PREDOMINATE PTYPE FROM
BRD TO HIB AND INL WITH SNOW/SLEET AT DLH AND SNOW/FZRA/SLEET/RAIN
AFFECTING HYR. THIS WILL PERSIST THROUGH THE FORECAST. GUSTY SFC
WINDS WILL PREVAIL THROUGH THE FORECAST AS WELL.
PREV DISCUSSION... /ISSUED 308 PM CDT SUN APR 14 2013/
SHORT TERM.../NOW - MONDAY/
THE FOCUS REMAINS THE WINTRY STORM SYSTEM THAT IS BEGINNING TO
MOVE INTO THE SOUTHERN FORECAST AREA. OVERALL...THIS SYSTEM HAS
BEEN DIFFICULT TO FORECAST FOR DUE TO DELAYS IN WHICH THE PCPN
FORMS AND MOVES INTO THE FORECAST AREA...CONSIDERABLE MODEL
DIFFERENCES IN SNOWFALL AMOUNTS...AND PCPN TYPE ISSUES FOR
NW WISCONSIN AND EAST CENTRAL MINNESOTA. THROUGH THE COURSE OF
THIS SHIFT...I HAVE ATTEMPTED TO DELAY THE ONSET OF THE PCPN AND
COMMUNICATE THE DELAY VIA THE GRAPHIC WEATHER STORY AND ON
FACEBOOK. THE MODELS SUGGEST THAT THE PCPN WILL INCREASE IN ITS
NORTHWARD SPEED LATER THIS AFTERNOON...SO I THINK WE MAY HAVE
FINALLY GOTTEN CLOSER TO BETTER DETERMINING TIMING. I EXTENDED
SOME ADVISORIES INTO EARLY THIS EVENING BASED ON THE PCPN DELAY
AND TO ALLOW THE EVENING SHIFT FORECASTER TIME TO SEE HOW THINGS
PAN OUT. I ALSO NOW THINK SOME AREAS OF NORTHERN MINNESOTA COULD
GET ANOTHER INCH OR TWO OF MORE SNOW THAN PREVIOUSLY
THOUGHT...SUCH AS ALONG THE NORTH SHORE.
THROUGH TONIGHT...A POTENT MID/UPPER LEVEL LOW IN THE NORTHERN
HIGH PLAINS AND ITS ASSOCIATED SURFACE LOW IN THE CENTRAL PLAINS
(EASTERN NEBRASKA AND WESTERN IOWA) WILL LIFT INTO MINNESOTA
TONIGHT. THE PCPN EXPECTED WITH THIS SYSTEM IS MOVING NORTHWARD
FROM EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN AND ALREADY
BEGINNING TO MOVE INTO NORTHEAST MINNESOTA AND NORTHWEST
WISCONSIN. THE PCPN IS EXPECTED TO SPREAD ACROSS THE REST OF THE
NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN THROUGH THE REST OF
THE AFTERNOON AND INTO THIS EVENING. THE MODELS SUGGEST THE
INITIAL BAND OF PCPN WILL COME DOWN AS SNOW AND MAY COME DOWN
QUITE FAST...WITH LIKELY SNOW RATES OF UP TO 1 TO 2 INCHES PER
HOUR IF NOT MORE. RECENT HRRR MODEL RUNS HAVE SHOWN SOME PERIODS
LATER THIS AFTERNOON OF 2 TO 3 INCHES PER HOUR. THERE IS STRONG
FRONTOGENESIS WITH THIS INITIAL BAND...SO IT IS CERTAINLY
POSSIBLE. CONSIDERING THE RELATIVELY WARM TEMPERATURES ACROSS THE
FORECAST AREA...MID 30S TO LOW 40S...THE PCPN MAY BRIEFLY BEGIN AS
A LIGHT RAIN BEFORE SWITCHING OVER TO SNOW ONCE THE RATES INCREASE
AND THE COLUMN COOLS. THERE WILL ALSO LIKELY BE A TRANSITION TO
SLEET AND RAIN ACROSS MUCH OF NORTHWEST WISCONSIN LATE THIS
AFTERNOON AND THIS EVENING. MUCH OF NORTHEAST MINNESOTA SHOULD GET
ABOUT 4 TO 9 INCHES OF SNOW...WITH THE GREATEST TOTALS ACROSS FAR
NORTHERN MINNESOTA. SOME AREAS MAY GET UP TO 10 INCHES...SUCH AS
ALONG THE NORTH SHORE OF LAKE SUPERIOR. I EXPECT LESS AMOUNTS OF
SNOW ACROSS NORTHWEST WISCONSIN AND EAST CENTRAL MINNESOTA BECAUSE
OF THE SLEET AND RAIN. HOWEVER...I WOULD NOT BE SURPRISED IF SOME
AREAS SEE CONSIDERABLE ACCUMULATION OF SLEET...WHICH IS WHY I
INCLUDED THE ACCUMULATION IN THE SNOW TOTALS I PROVIDED IN THE
WINTER WEATHER ADVISORIES FOR NORTHWEST WISCONSIN. STRONG EAST
WINDS ARE DEVELOPING ACROSS THE FORECAST AREA THIS AFTERNOON...AND
THEY SHOULD CONTINUE TO STRENGTHEN INTO THIS EVENING. THE WINDS
WILL BE STRONGEST NEAR LAKE SUPERIOR...ESPECIALLY NEAR THE TWIN
PORTS. THE 15 TO 30 MPH WINDS WITH GUSTS UP TO 40 MPH NEAR LAKE
SUPERIOR COULD REALLY REDUCE VISIBILITY DURING THE HEAVIER SNOW
BANDS AND CAUSE BRIEF NEAR WHITE-OUT CONDITIONS.
MONDAY...THE SNOW WILL LIKELY CONTINUE ACROSS MOST OF THE FORECAST
AREA THROUGH AT LEAST THE EARLY AFTERNOON AS THE LOW LIFTS INTO
ONTARIO. UP TO ADDITIONAL 1 TO 3 INCHES OF SNOW COULD FALL ACROSS
THE NORTHERN FORECAST AREA DURING THE DAY. THE WINTER STORM
WARNING FOR THE NORTHERN FORECAST AREA RUNS THROUGH 15Z TOMORROW
MORNING...BUT WE MIGHT NEED TO EXTEND THE WARNING INTO SUNDAY
AFTERNOON IF THE SNOW AND REDUCED VISIBILITY ARE STILL LINGERING.
GUSTY SOUTH TO SOUTHWEST WINDS WILL DEVELOP IN THE WAKE OF THE
PASSING LOW PRESSURE SYSTEM. TEMPERATURES SHOULD BE IN THE UPPER
30S TO LOW 40S.
LONG TERM.../MONDAY NIGHT - SATURDAY/
THE UPPER LOW WILL BE OVER THE NORTHERN MINNESOTA/NORTHERN LAKE
SUPERIOR AREA 00Z TUESDAY THEN CONTINUE E/NE MONDAY NIGHT. A BAGGY
UPPER TROUGH...WITH AN EXTENSION TO THE SURFACE WILL REMAIN OVER
THE CWA INTO MONDAY NIGHT. WE KEPT A CHANCE FOR SNOW OVER MUCH OF
OUR NORTHEAST MINNESOTA ZONES MONDAY NIGHT...WITH THE BEST CHANCE
OVER THE BORDER REGION.
AN UPPER RIDGE WILL BUILD OVER THE REGION BRIEFLY TUESDAY...WITH
MOST AREAS DRY INTO TUESDAY NIGHT.
A DEEP TROUGH WILL THEN MOVE OVER THE ROCKIES TUESDAY
NIGHT...MOVING SLOWLY EAST THROUGH THE WEEK AFFECTING THE
NORTHLAND. ANOTHER SPRING STORM IS POISED TO AFFECT THE NORTHLAND
WEDNESDAY INTO AT LEAST THURSDAY...POSSIBLY LINGERING A BIT
LONGER. BOTH THE GFS AND ECMWF ARE IN GENERAL AGREEMENT WITH THE
TRACK OF THE SURFACE LOW...TAKING IT FROM THE TEXAS PANHANDLE AT
12Z WEDNESDAY TO LAKE MICHIGAN/SOUTHEAST WISCONSIN BY 12Z
THURSDAY...THEN IT CONTINUES NORTHEAST. AS IS THE CASE WITH THESE
SPRING STORMS...THE THERMAL PROFILES WILL BE CRITICAL TO PRECIP
TYPE. IT DOES APPEAR TEMPERATURES WILL BE WARM ENOUGH FOR A MIX
OVER AT LEAST NORTHWEST WISCONSIN. WE HAVE A RAIN/SNOW MIX OVER
NORTHWEST WISCONSIN WEDNESDAY NIGHT/THURSDAY...AND WILL LIKELY
NEED TO ADJUST THAT AS THIS SYSTEM NEARS. THE THREAT FOR MORE
ACCUMULATING SNOW IS INCREASING OVER NORTHEAST MINNESOTA INTO FAR
NORTHWEST WISCONSIN WEDNESDAY INTO THURSDAY. IT`S VERY DIFFICULT
TO TRY AND PLACE A NUMBER ON SNOW ACCUMULATION AT THIS POINT WITH
SO MUCH UNCERTAINTY REVOLVING THE PRECIP TYPE...BUT AT LEAST
SEVERAL INCHES OF SNOW WILL FALL OVER EASTERN MINNESOTA/FAR
NORTHWEST WISCONSIN FROM THIS SYSTEM. THE FORECAST MID-LATE WEEK
IS WORTH MONITORING CLOSELY AS THE PROBABILITY IT WILL HAVE A
SIGNIFICANT IMPACT ON THE NORTHLAND/S WEATHER IS INCREASING. MORE
DETAIL REGARDING PRECIP TYPE/AMOUNTS WILL BE ADDED AS WE PROGRESS
INTO THE EARLY PART OF THE WEEK.
AS THE UPPER TROUGH PASSES LATE IN THE WEEK...A SURFACE HIGH WILL
MOVE OVER THE AREA DRYING THINGS OUT FOR A TIME LATE IN THE
WEEK/EARLY WEEKEND. ANOTHER SHORTWAVE WILL BRING ANOTHER CHANCE
FOR MIXED PRECIP SATURDAY NIGHT/SUNDAY BUT THIS SYSTEM DOES NOT
LOOK TO BE PARTICULARLY STRONG.
TEMPERATURES THROUGH MOST OF THE PERIOD WILL REMAIN BELOW NORMAL.
AVIATION.../18Z TAFS/
AREA RADARS SHOWED PRECIPITATION WAS MOVING NORTH THROUGH
MINNESOTA/WISCONSIN...AND WAS BECOMING MORE WIDESPREAD. THE NAM
HAS A PRETTY GOOD HANDLE ON THIS...AS DO THE HIGH RES MODELS. WE
EXPECT THE PRECIPITATION TO BEGIN AS SNOW ALL AREAS...THEN IT MAY
BECOME A WINTRY MIX AT KHYR...AND POSSIBLY AT KBRD BRIEFLY. TIMING
IN THE TAFS MAY NEED TO BE ADJUSTED BY AN HOUR OR SO...AND WE`LL
DO THAT AS CONFIDENCE INCREASES FOR AN EXACT STARTING TIME.
VSBYS WILL DROP TO IFR OR LIFR WITHIN AN HOUR OF PRECIP
ONSET...AND AREAS AROUND LAKE SUPERIOR WILL SEE WINDY CONDITIONS
FURTHER REDUCING THE VSBY IN BLOWING SNOW. A DRY SLOT WILL WORK
NORTH LATER THIS EVENING/TONIGHT AND CAUSE THE PRECIP TO DIMINISH
OVER MOST OF THE TAFS. FORECAST SOUNDINGS SHOW TOP DOWN
DRYING...SO SOME SPOTTY DRIZZLE OR FREEZING DRIZZLE IS NOT OUT OF
THE QUESTION. WE DID NOT ADD THAT TO THE TAFS AT THIS TIME...AS
THAT IS MORE OF A SHORT TERM FORECAST ISSUE AND CAN BE ADDRESSED
WITH LATER UPDATES.
WINDS WILL SWITCH FROM EASTERLY TO SOUTHERLY LAT TONIGHT/MONDAY
MORNING...THEN BECOME SOUTHWEST.
&&
.POINT TEMPS/POPS...
DLH 30 38 26 34 / 20 10 10 50
INL 26 36 24 37 / 50 20 10 40
BRD 29 38 28 38 / 10 10 10 60
HYR 30 42 27 41 / 10 10 10 60
ASX 31 41 27 37 / 10 10 10 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT THIS MORNING FOR MNZ025-026-
033>035-037.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT EARLY THIS MORNING FOR
MNZ036-038.
WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ010>012-
018>021.
WI...WINTER WEATHER ADVISORY UNTIL 1 AM CDT EARLY THIS MORNING FOR
WIZ003-004-006>009.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT THIS MORNING FOR WIZ001-
002.
LS...GALE WARNING UNTIL 3 AM CDT EARLY THIS MORNING FOR LSZ121-
140>148.
&&
$$
SHORT TERM...CANNON
LONG TERM....DAP
AVIATION...DAP
AREA FORECAST DISCUSSION
NWS NORMAN OK
1151 PM CDT SUN APR 14 2013
.UPDATE...
LOWERED POPS FOR THE REST OF THE NIGHT...
&&
.DISCUSSION...
ONLY HAD A FEW UPDRAFTS DEVELOP THIS EVENING ALONG THE COLD FRONT
CURRENTLY MOVING SOUTHWARD ACROSS THE SOUTHERN PLAINS. THROUGH 11
PM CDT...ALL CONVECTION HAD CEASED...AS A DRY AND STABLE AIR MASS
WAS QUICK TO SPREAD ACROSS NORTHERN OKLAHOMA AND KANSAS ON THE
HEELS OF THE FRONT. WEATHER SHOULD REMAIN QUIET THROUGH THE
OVERNIGHT FOR OKLAHOMA AND WESTERN NORTH TEXAS. LOWS WILL BE MILD
FROM THE RED RIVER VALLEY...UPPER 50S TO LOWER 60S...TO SEASONABLE
ACROSS NORTHERN AND NORTHWESTERN OKLAHOMA...MID TO UPPER 40S.
WINDS ACROSS SOUTHERN OKLAHOMA AND NORTHERN TEXAS WILL CONTINUE TO
SHIFT OUT OF THE NORTHWEST. WITH WINDS BEHIND THE FRONT BREEZY AT
TIMES...20 TO 25 MPH.
JTK
&&
.PREV DISCUSSION... /ISSUED 639 PM CDT SUN APR 14 2013/
UPDATE...
MESOSCALE ENVIRONMENT UPDATE...
DISCUSSION...
A FEW WEAK UPDRAFTS HAVE FINALLY BEEN ABLE TO FIRE ACROSS NORTH
CENTRAL OKLAHOMA WITHIN A REGION OF CU DEVELOPMENT FOCUSED ALONG
THE FRONTAL BOUNDARY. 14/23Z SURFACE ANALYSIS PLACES THE FRONT
FROM SWRN IA SOUTHWEST THROUGH THE TX PANHANDLE. 21Z RAP SOUNDINGS
AT 23Z JUST AHEAD OF THE FRONT REVEAL A FAIRLY DECENT MIXING FROM
THE SURFACE THROUGH APPROXIMATELY 850MB. WITH SKINNY CAPE
PROFILES...MLCAPE VALUES ON RANGE FROM 250 TO 500 J/KG.
HOWEVER...RAP 0-1KM AGL COMPUTED CAPE (LOW LVL CAPE) SHOWS A NICE
POCKET OF 400 TO 550 J/KG NEAR WHERE 50-60 DPTS HAVE POOLED NEAR
THE INTERSECTION OF THE DRY LINE AND COLD FRONT ACROSS N CENTRAL
OK.
UPSTREAM SURFACE ANALYSIS WOULD INDICATE A SHALLOW PROFILE FOR THE
COLD FRONT. AT 14/23Z...TEMPS BEHIND THE FRONT RANGE FROM THE
UPPER 60S/LOWER 70S ACROSS SRN KS...TO THE MID 50S/LOWER 60S
ACROSS SRN NE. THE COMBINATION OF MIXING AT THE SURFACE...MODEST
INSTABILITY AND WEAK LIFT FROM THE FRONT ARE LIKELY REASON THE
CURRENT UPDRAFTS...WHICH DEVELOPED APPROXIMATELY 530ISH...HAVE
CONTINUED TO STRUGGLE.
HOWEVER...RADAR ANALYSIS INDICATES CURRENT CONVECTION MAY BE
DEVELOPING ALONG A PRE-FRONTAL WIND SHIFT/SFC TROUGH...AS A
SECOND BOUNDARY IS DEFINED ON KVNX FROM NEAR CARRIER TO BRAMAN.
BEHIND THIS BOUNDARY...AIR IS A BIT COOLER (LOWER 70S) AND DRIER
(MID 50S DPTS). AS THIS BOUNDARY CATCHES UP WITH THE ONGOING
CONVECTION...IT COULD OFFER SOME ENHANCEMENT.
OVERALL...SEVERE THREAT FOR NORTH CENTRAL OKLAHOMA LOOKS TO BE
DIMINISHING SLIGHTLY FOR THE MOMENT. HOWEVER...IF THE SECONDARY
BOUNDARY OFFERS A BETTER SOURCE OF LIFT...ONE COULD NOT RULE OUT
AT THIS TIME A FEW STRONG TO SEVERE STORMS DEVELOPING. HAIL TO THE
SIZE OF QUARTERS AND WINDS NEAR 60 MPH WOULD BE THE PRIMARY
CONCERNS.
JTK
PREV DISCUSSION... /ISSUED 238 PM CDT SUN APR 14 2013/
DISCUSSION...
COLD FRONT MOVING THROUGH NORTHWEST OKLAHOMA WILL CONTINUE TO MOVE
SOUTH AND EAST ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT. A
FEW STORMS MAY DEVELOP ALONG THE FRONT LATER TODAY ACROSS MAINLY
NORTH CENTRAL OKLAHOMA. ENOUGH INSTABILITY WILL EXIST FOR THE
POSSIBILITY OF SEVERE WEATHER ASSOCIATED WITH THESE STORMS.
THIS FRONT WILL STALL LATE TONIGHT AND HANG OUT NEAR OR JUST
SOUTH OF THE I-44 CORRIDOR ON MONDAY. WITH NO STRONG FORCING AND
SOME CAPPING ISSUES MUCH OF MONDAY SHOULD REMAIN DRY. THIS FRONT
IS THEN EXPECTED TO TRY AND RETREAT BACK NORTH MONDAY NIGHT AS IT
IS INFLUENCED BY THE STRONGER STORM SYSTEM THAT WILL APPROACH THE
AREA LATER THIS WEEK. AN ISOLATED STORM OR TWO MAY TRY TO DEVELOP
ALONG FRONT OR DRYLINE LATE TUESDAY AFTN INTO THE EVENING HOURS
WITH PERHAPS A BIT BETTER CHANCE TUESDAY NIGHT WITH AID OF
DEVELOPING LLJ.. MAINLY CENTRAL INTO NORTHERN OKLAHOMA.
BY THE TIME WE GET TO WEDNESDAY... SIGNIFICANT DIFFERENCES CONT TO
REMAIN BETWEEN THE MODELS IN LOCATION OF SFC BOUNDARIES. THE
LATEST GFS CONT TO WANT AND TRY TO LIFT THE BOUNDARY WELL NORTH
INTO KANSAS WITH DRYLINE NEAR THE OK/TX BORDER WED AFTN... PUTTING
ALL OF THE AREA IN WARM SECTOR AND A MUCH HIGHER PROBABILITY OF
STRONG/SEVERE STORMS AND HEAVY RAIN ACROSS MUCH OF THE AREA.
HOWEVER... EURO KEEPS BOUNDARY MUCH FARTHER SOUTH AND THIS MAKES
MORE SENSE AS COLDER AIR TO THE NORTH OF THE FRONT WILL BE HARD TO
DISLODGE AND WITH ABUNDANT CLOUD COVER AND PERHAPS ONGOING PRECIP
HAVE A HARD TIME SEEING THIS BOUNDARY MOVE AS FAR NORTH AS GFS
SEEMS TO THINK. WILL THEREFORE CONT TO FOLLOW THE EURO AND KEEP
THE SFC BOUNDARY NEAR OF JUST NORTH OF I-44 CORRIDOR DURING THE
DAY ON WEDNESDAY BEFORE IT SURGES SOUTH LATE WEDNESDAY AND
WEDNESDAY NIGHT.
MUCH COLDER AIRMASS WILL THEN SURGE SOUTH OVERSPREADING THE AREA
WITH A CHANCE TO SEE SOME WINTRY PRECIP... HOWEVER LATEST TRENDS
CONT TO SHOW THIS BEING LESS OF A POSSIBILITY. FOR NOW WILL KEEP A
MENTION OF THIS FOR CONSISTENCY SAKE.
ANOTHER FREEZE MAY THEN OCCUR ACROSS PARTS OF NORTHERN OKLAHOMA
THURSDAY MORNING AND THEN AGAIN FRIDAY MORNING. FREEZING TEMPS
COULD GET NEAR CENTRAL AND INTO SOUTHWEST OKLAHOMA FRIDAY MORNING.
ANOTHER WEAKER FRONT WILL APPROACH NEXT WEEKEND... KEEPING TEMPS
BELOW NORMAL THROUGH REMAINDER OF EXTENDED.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 54 73 55 73 / 10 10 10 10
HOBART OK 48 72 52 74 / 10 10 10 10
WICHITA FALLS TX 55 83 61 87 / 0 10 10 10
GAGE OK 44 66 43 64 / 10 0 10 10
PONCA CITY OK 50 65 46 63 / 40 10 20 10
DURANT OK 64 84 65 83 / 0 10 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/02
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1200 AM CDT MON APR 15 2013
.SHORT TERM...
712 PM CDT SUN APR 14 2013
WARM FRONT IS MAKING NORTHWARD PROGRESS ACROSS THE SOUTHERN
PORTIONS OF THE FORECAST AREA EARLY THIS EVENING. TEMPERATURES
WARMED INTO THE LOWER 40S AS FAR NORTH AS KAUM-KFKA-KY51-KDLL
THROUGH 00Z. READINGS HAD SURGED INTO THE LOWER 60S OVER THE FAR
SOUTHERN PART OF THE FORECAST AREA...BUT NOW THAT THE SUN IS
SETTING EXPECT THAT TO FALL BACK. MEANWHILE THE COLD FRONT WAS
MAKING EASTWARD PROGRESS ACROSS CENTRAL IA AS THE SECONDARY LOW
ALONG THE MN/IA BORDER MOVED NORTHEAST. FINALLY...FURTHER NORTH
THE REGION REMAINS LOCKED INTO THE COOL AIR AND MIXED
PRECIPITATION. FROM REPORTS RECEIVED IN WESTERN AND NORTH CENTRAL
WI...OPTED TO EXTEND THE ADVISORY THROUGH 06Z...AND PRECIPITATION
WILL CONTINUE AND TEMPERATURES WILL LIKELY NOT BUDGE.
SHORT TERM MESOSCALE MODELS ARE HANDLING THE SITUATION REASONABLY
WELL...AND HAVE FOLLOWED THE HRRR AND ARXLAPS MODEL RUNS FOR
UPDATES THIS EVENING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CDT SUN APR 14 2013
UPPER LEVEL RIDGING TRANSITIONS OVER THE UPPER MISSISSIPPI RIVER
VALLEY WITH THE EXIT OF THE LOW PRESSURE SYSTEM. THE 14.12Z GFS/NAM
WOULD BRING PIECES OF UPPER LEVEL ENERGY ACROSS THE TOP OF THE
RIDGE...WHILE OVER IA/NORTHERN ILL THEY BOTH SUGGEST AN AREA OF LOW
LEVEL WARM AIR ADVECTION/ISENTROPIC UPGLIDE/SLOPING FRONTOGENETIC
LIFT. BOTH AREAS COULD HAVE ENOUGH FORCING FOR LIGHT PCPN
PRODUCTION...AND THIS IS REFLECTED IN THE GFS/NAM QPF FIELDS. BETTER
CHANCES WOULD BE TO THE SOUTH. HOWEVER...SATURATION LOOKS TO BE AN
ISSUE. NORTH-SOUTH RUNNING X-SECTIONS AND BUFKIT SOUNDINGS SHOW AN
INCREASE IN MOISTURE FROM THE SOUTH...MOSTLY CONFINED AROUND 700
MB...WITH A RELATIVELY DRY ATMOSPHERE SUB 850 MB. THINK THERE WILL
BE ENOUGH LIFT TO WORK WITH THE AVAILABLE SATURATION TO GET THROUGH
THAT DAY LAYER...MOSTLY AS SPRINKLES TO LIGHT SHOWERS. ACCUMULATIONS
LOOK MINIMAL AT THE MOMENT...WITH CHANCES CONFINED TO PARTS OF
NORTHEAST IA/SOUTHWEST WI.
STORM SYSTEM STILL SLATED TO IMPACT THE AREA IN THE WED NIGHT/THU
TIME FRAME...WITH THE GFS/ECMWF BRINGING A SFC LOW FROM THE SOUTHERN
PLAINS TO ACROSS NORTHERN ILL BY 06Z THU. THE GEM IS A BIT FARTHER
NORTH...BUT HAS SIMILAR TIMING. CURRENT TRACK WOULD ALLOW FOR THE
SYSTEM TO BRING A GOOD AMOUNT OF LOW LEVEL WARM AIR
NORTHWARD...WHICH WOULD RESULT IN MAINLY RAIN FOR THE LOCAL FORECAST
AREA...AND THE SYSTEM/S DEFORMATION SNOW BAND LAYING UP ACROSS
NORTHERN MN. THAT SAID...THE MODELS HAVE BEEN JUMPING AROUND QUITE A
BIT...SO CONFIDENCE IS SHAKY IN JUST HOW THIS WILL PLAY OUT. CHANCES
FOR PCPN LOOK FAIRLY HIGH...EVEN LIKELY...BUT JUST WHAT WILL FALL
AND HOW MUCH IS STILL UNCERTAIN. CAN/T RULE OUT ANOTHER SHOT FOR
LATE SEASON SNOW.
CYCLONIC FLOW POST THIS STORM SYSTEM COULD KEEP SOME SMALL PCPN
CHANCES LINGERING INTO NEXT WEEKEND. THERE WILL ALSO BE ANOTHER SHOT
OF UNSEASONABLY COLD AIR. HIGHS WILL BE STUCK IN THE 40S
THU-FRI...WITH BELOW FREEZING LOWS.
&&
.AVIATION...THROUGH 06Z TUESDAY
1157 PM CDT SUN APR 14 2013
RAIN AND ASSOCIATED REDUCTION IN VISIBILITY HAS MOVED EAST OF THE
TAF SITES AS OF 1130 PM. LOW CLOUDS HAVE CLEARED KRST AND WILL
CLEAR KLSE SHORTLY. IMPROVING TREND WILL CONTINUE THROUGH THE
NIGHT. WITH ALL OF THE MOISTURE...SOME THOUGHT FOR FOG POSSIBILITY...
BUT WITH INCREASING WEST WIND AND INFLUX OF DRIER AIR FEEL IT WILL
NOT BE AN ISSUE. WINDS WILL BE KICKING UP FROM THE WEST-SOUTHWEST
AS THE LOW WRAPS UP. SOME GUSTS UP IN THE 20-30 KT RANGE
POSSIBLE...ESPECIALLY ACROSS THE HIGHER TERRAIN...AFFECTING KRST.
&&
.HYDROLOGY...THIS WEEK
ISSUED AT 310 PM CDT SAT APR 12 2013
THE CURRENT PRECIPITATION EVENT IS STILL ON TRACK TO PRODUCE BETWEEN
1 AND 1.5 INCHES OF LIQUID ACROSS MUCH OF THE REGION. THE SLOWER
PROGRESSION OF THE STORM SYSTEM WILL SHIFT THE AXIS OF HEAVIER
RAINFALL A BIT WESTWARD...NOW MORE ALONG AND EAST OF THE MISSISSIPPI
RIVER. LATER THIS EVENING AS THE COLD FRONT CROSSES...CONVECTION
COULD LEAD TO ISOLATED HIGHER RAINFALL AMOUNTS WITH SOME 2.0 INCH
TOTALS POSSIBLE. REGARDLESS...THE FORECAST QPF BRINGS ANOTHER ROUND
OF SIGNIFICANT RISES ON THE BLACK AND KICKAPOO RIVER BASINS TO JUST
SHY OF FLOOD STAGE. ON THE TREMPEALEAU RIVER AT DODGE...A
CONTINUATION OF MINOR FLOODING IS EXPECTED. OTHER TRIBUTARIES ACROSS
SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WESTERN WISCONSIN WILL
SEE WITHIN-BANKFULL RISES OVER THE NEXT FEW DAYS. THE CAVEAT IS IF
OBSERVED RAINFALL TONIGHT IS MUCH HIGHER THAN FORECAST...THEN FLOOD
WARNINGS WOULD BE NEEDED FOR A FEW SITES ON THE KICKAPOO AND
BLACK...SO THOSE WITH INTERESTS ON AREA RIVERS SHOULD STAY TUNED TO
THE LATEST RIVER STATEMENTS AND FORECASTS.
THE MAIN STEM OF THE MISSISSIPPI RIVER WILL REMAIN NEARLY STEADY OR
SEE A GRADUAL UPTICK THIS WEEK AS RAIN AND SNOWMELT TODAY/TONIGHT
WORKS ITS WAY DOWNSTREAM. THE ONLY EXCEPTION IS AT MCGREGOR
IOWA...WHERE THE RIVER LEVEL RISES ENOUGH SUCH THAT BY WEDNESDAY
NIGHT INTO THURSDAY IT APPROACHES FLOOD STAGE.
LOOKING AHEAD...ANOTHER SYSTEM SYSTEM LOOKS TO IMPACT THE ENTIRE
REGION WEDNESDAY NIGHT AND THURSDAY. CURRENT HPC DAY 4-5 QPF POINTS
TO ANYWHERE FROM 3/4 TO 1.5 INCHES OF LIQUID. THESE AMOUNTS
CERTAINLY WOULD INITIATE SOME AND/OR PROLONG FLOODING CONCERNS
ACROSS THE REGION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
712 PM CDT SUN APR 14 2013
WI...WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM....RIECK
AVIATION...MW
HYDROLOGY....ZT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1128 PM CDT SUN APR 14 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...
ISSUED AT 813 PM CDT SUN APR 14 2013
MAIN AREA OF PCPN WAS OCCURRING ACROSS NC WI EARLY THIS EVG...WITH
DRY CONDITIONS FARTHER SE...INCLUDING THE FOX VALLEY AND LKSHR AREAS.
WARM AIR ALOFT HAD CHANGED THE SNOW TO FREEZING RAIN OVER NC WI...
WHERE SFC TEMPS WERE STILL AT OR SLIGHTLY BLO FREEZING. SFC WET BULB
TEMPS REMAINED BLO FREEZING OVER NC/FAR NE WI...AND MODEL FCSTS SHOW
THIS CONTINUING OVER FAR NORTHERN WI UNTIL AT LEAST 06Z. GIVEN THIS...
PLUS SEVERAL REPORTS OF ICING AND ONE REPORT OF CARS IN DITCHES...
HAVE OPTED TO ISSUE A FREEZING RAIN ADVISORY FOR THE NEXT 5 HOURS
OR SO.
RAIN WILL FILL IN ACROSS THE SE HALF OF THE CWA LATE THIS EVG AND
EARLY MONDAY MORNING...AS THE OCCLUDED FRONT MOVES THROUGH. ONCE
THE FRONT PASSES THROUGH...PCPN SHOULD DECREASE RAPIDLY. ALTHOUGH
TSTMS OVER N IA HAVE DISSIPATED...DECIDED TO KEEP A CHANCE OF THUNDER
IN C/EC WI DURING THE LATE EVG/EARLY MONDAY MORNING PERIOD...AS BEST
LI`S DROP TO ZERO TO -1 C.
HOURLY POP/WX GRIDS HAVE BEEN UPDATED TO MATCH EXPECTED TRENDS FOR
THE REST OF THE NIGHT.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ELONGATED LOW
PRESSURE SPINNING ALONG THE IOWA/NEBRASKA BORDER THIS
AFTERNOON...AND A SURFACE WARM FRONT EXTENDING EASTWARD ACROSS
NORTHERN ILLINOIS. SOUTH OF THE WARM FRONT...TEMPERATURES ARE IN
THE 60S AND 70S. BUT NORTH OF THE FRONT...A 50KT SSW LLJ IS LEADING TO
A BAND OF PRECIPITATION WHICH IS NOW PUSHING INTO THE NORTHERN
SECTIONS OF THE BADGER STATE. TEMPERATURES REMAIN IN THE 20S AND
30S WITHIN THIS BAND OF PRECIP...WHERE LOCATIONS OVER CENTRAL
WISCONSIN HAVE PICKED UP A QUICK 2-3 INCHES OF WET SNOW. A FEW
SPOTTER REPORTS HAVE CONFIRMED WHAT DUAL POL IS SHOWING...THAT SNOW
IS MIXING WITH RAIN AND SLEET...WITH THE CHANGE OVER NOW SPREADING
INTO SOUTHERN MARATHON AND SHAWANO COUNTIES. ADDITIONALLY...SURFACE
WET BULB ZERO TEMPS ARE SPREADING NORTHEAST INTO EAST-CENTRAL
WISCONSIN...SO SHOULDNT SEE TOO MUCH MORE ACCUMS IN THESE AREAS.
STILL EXPECTING THE MODERATE TO HEAVY SNOW TO SPREAD INTO
NORTH-CENTRAL WISCONSIN THIS AFTERNOON WHERE A QUICK 3 INCHES WILL
LIKELY FALL. WILL CONTINUE TO HANDLE THE SNOWFALL WITH SPS
UPDATES. PRECIP CONTINUES TO BE THE MAIN FORECAST CONCERN FOR THIS
FORECAST.
TONIGHT...LOW PRESSURE WILL OCCLUDE AS IT LIFTS NORTH OVER SOUTHERN
MINNESOTA...WHILE THE OCCLUDED/COLD FRONT WILL SWEEP ACROSS THE AREA
LATE THIS EVENING AND THROUGH THE OVERNIGHT HOURS. SNOW/SLEET LOOK
TO BE ONGOING OVER NORTH-CENTRAL WISCONSIN AT THE START OF THE
EVENING WHILE CONDITIONS LOOK TO BE DRY FOR A PERIOD OVER
EAST-CENTRAL AND POSSIBLY FAR NORTHEAST WISCONSIN. THIS DRY PERIOD
OVER THE EAST WILL BE SHORT-LIVED HOWEVER...AS A BAND OF SHOWERS AND
EMBEDDED THUNDERSTORMS WILL MOVE THROUGH ALONG THE OCCLUDED/COLD
FRONT. PROGGED SOUNDINGS INDICATE THAT PTYPE SHOULD BE MAINLY RAIN
ACROSS THE REGION BY THE TIME THIS BAND ARRIVES...WHICH WILL LOOK TO
DUMP AROUND 0.75 INCHES OF RAIN OVER WESTERN SECTIONS OF THE CWA.
AMOUNTS SHOULD DROP OFF TO THE EAST AS INSTABILITY IS LOST THROUGH
THE NIGHT. BEST CHANCES OF THUNDER LOOK TO OCCUR OVER CENTRAL AND
EAST-CENTRAL AND WILL KEEP IT IN THE FORECAST. TEMPERATURES WILL
LIKELY PEAK LATE IN THE EVENING OR EARLY OVERNIGHT...JUST AHEAD OF
THE FRONT. LOWS IN THE 30S AND 40S.
MONDAY...OCCLUDED LOW PRESSURE WILL LIFT NE ACROSS NORTHERN
MINNESOTA. PRECIP WILL HAVE EXITED ALONG THE FRONT BY THE START OF
THE PERIOD AND SKIES WILL LIKELY TURN MOSTLY CLEAR FOR A PERIOD
DURING THE MORNING. HOWEVER...AS COLDER AIR FILTERS IN FROM THE
WEST AND MID-LEVEL TEMPS COOL...STEEPENING LOW LEVEL LAPSE RATES AND
WRAP AROUND MOISTURE WILL LEAD TO INCREASING CLOUDS FROM LATE
MORNING THROUGH THE REST OF THE DAY. COULD SEE A FEW INSTABILITY
RAIN AND SNOW SHOWERS DEVELOP OVER CENTRAL AND NORTHEAST WISCONSIN
IN THE AFTERNOON. GUSTY SOUTHWEST WINDS WILL BRING IN THE WARMEST
TEMPS THE AREA HAS SEEN IN SOME TIME...AND WILL GO WITH HIGHS
RANGING FROM THE LOW 40S NORTH TO THE MID 50S NEAR LAKE MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
FLOOD POTENTIAL IS PROBABLY THE MAIN CHALLENGE FOR THIS FORECAST
PERIOD. THE COLD FRONT MOVES THROUGH MONDAY WITH DRY BUT
SEASONABLE AIR FOLLOWING FOR MONDAY NIGHT THROUGH TUESDAY NIGHT.
SNOW WILL PROBABLY BE GONE OVER MUCH OF THE AREA BELOW 1000 FT
ELEVATION BY THEN WITH THAT SNOW MELT PROBABLY CONTRIBUTING TO
RISES OF THE WOLF RIVER AND SMALL STREAMS OVER EAST CENTRAL
WISCONSIN. MODELS ARE NOW IN GENERAL AGREEMENT WITH SURFACE LOW THAT
MOVES NORTHEAST FROM SOUTHERN PLAINS TO LOWER MICHIGAN WEDNESDAY
THROUGH THURSDAY. LOOKS LIKE THIS WILL BE A LARGELY RAIN EVENT
UNLESS THE STORM TRACKS FURTHER SOUTH. A RAIN EVENT COUPLED BY
SNOW MELT IN THE NORTH WILL LIKELY CAUSE SOME FLOODING OF SMALL
STREAMS AROUND THE AREA BY THURSDAY BUT SIGNIFICANTLY COLDER AND
DRIER AIR WILL SLOW SNOW MELT FRIDAY AND SATURDAY.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1120 PM CDT SUN APR 14 2013
TEMPERATURES WILL CONTINUE TO GRADUALLY WARM OVERNIGHT...SO ANY
LINGERING FREEZING RAIN IN NC WI SHOULD COME TO AN END. SINCE TEMPS
HAVE RISEN TO JUST ABOVE FREEZING AT RHI/AUW/CWA...DO NOT PLAN TO
CARRY ANY FREEZING RAIN ON THE 06Z TAFS. A LARGE BAND OF SHOWERS WILL
ACCOMPANY A FRONTAL BOUNDARY AS MOVES THROUGH THE AREA OVERNIGHT. THE
SHOWERS SHOULD END FROM WEST TO EAST BETWEEN 08Z-10Z. THE MAIN FOCUS
FOR THUNDERSTORMS APPEARS TO HAVE SHIFTED SOUTH...SO WILL NOT MENTION
ANY TSTMS IN THE NEW SET OF TAFS. AFTER THE PCPN ENDS...SOME SCT
IFR/MVFR CIGS WILL LIKELY LINGER LATE TONIGHT INTO EARLY MONDAY.
GUSTY SW WINDS ARE EXPECTED TO DEVELOP BY MIDDAY MONDAY.
LLWS WILL CONTINUE ACROSS THE REGION UNTIL THE OCCLUDED FRONT
MOVES THROUGH OVERNIGHT. THE LLWS SHOULD WANE AT THE TAF SITES
FROM WEST TO EAST BETWEEN 08Z-10Z.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN APR 14 2013
CONTINUED CONCERNS FOR FLOODING ISSUES GIVEN EXPECTED
QPF WITH THE FRONTAL PASSAGE TONIGHT. AN ADDITIONAL THREE QUARTERS
TO AN INCH OF PRECIP MAY FALL OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN BY MONDAY MORNING. WARMER TEMPERATURES TONIGHT AND MONDAY
WILL ADD SNOW MELT INTO THE EQUATIONS. CONCERNS ADDRESSED IN CURRENT
ESF PRODUCT AND RIVER FLOOD STATEMENTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ005-010>012-
018-019.
&&
$$
UPDATE.........KIECKBUSCH
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
537 AM EDT MON APR 15 2013
.SYNOPSIS...
HIGH PRESSURE WILL BE IN PLACE TODAY WITH FAIR WEATHER EXPECTED. A
COLD FRONT APPROACHES FROM THE WEST TUESDAY...BRINGING WITH IT
SHOWERS. HIGH PRESSURE BUILDS IN FROM THE NORTH DURING THE DAY
WEDNESDAY INTO WEDNESDAY NIGHT. A WARM FRONT LIFTS NORTH ACROSS
THE REGION ON THURSDAY. ANOTHER COLD FRONT SLOWLY MOVES ACROSS THE
REGION FRIDAY THROUGH SATURDAY...PRODUCING ANOTHER THREAT FOR
SHOWERS. COOLER HIGH PRESSURE BUILDS IN ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...A FEW CHANGES TO REFLECT CURRENT OBSERVATIONAL TRENDS.
BACKDOOR COLD FNT LIKE FEATURE IS SPREADING LOW CLOUDS INTO
DOWNEAST ATTM. TIME OF ARRIVAL TOOL AS WELL AS LATEST HRRR BRING
THIS DECK INTO THE WRN PENOBSCOT BAY AREA AROUND 12Z BEFORE
SCATTERING OUT. HAVE UPDATED THE SKY GRIDS TO REFLECT THIS.
PREVIOUS DISCUSSION...HIGH PRES HAS SETTLED ACROSS THE NORTHEAST
THIS MORNING. THIS SHOULD KEEP CLOUDS ASSOCIATED WITH LIFTING WARM
FNT MOSTLY AT BAY...EXCEPT FOR SOME HIGH...THIN CLOUDINESS.
WEAK PRES GRADIENT WILL ALLOW FOR SEA BREEZE TO DEVELOP WITH
DAYTIME HEATING. THIS ONSHORE FLOW WILL MOST AFFECT WRN ME. THIS
WILL KEEP TEMPS IN THE 50S...WHILE SLY FLOW AND MOSTLY SUNNY SKIES
ACROSS NH WILL BRING SRN AREAS TO NEAR 60. BLENDED IN THE LOCAL
WRF TEMPS TO TRACK PROGRESS OF SEA BREEZE FNT INLAND DURING THE
DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MID LVL WARM FNT WILL CONTINUE LIFTING ACROSS THE AREA TONIGHT.
CLOUDS WILL GENERALLY BE OF A MID TO HIGH LVL VARIETY...SO PLAYED
THEM DOWN A LITTLE IN THE GRIDS AS THE IMPACT SHOULD BE MINOR.
WARM FNT CONTINUES TO LIFT THRU THE CWAF TUE...BUT MODEL GUIDANCE
CAN GET OVERLY AGGRESSIVE IN BRINGING THESE FEATURES NWD THIS TIME
OF YEAR. HOWEVER...IN THIS CASE NWP HAS A NICE CONSENSUS OF THE
FNT HANGING UP AROUND THE MIDCOAST AND STRUGGLING TO BRING SFC
WARMTH THAT FAR N. AS SUCH A MAV/MET/ECMWF MOS BLEND LOOKED GOOD
FOR TEMPS. ALSO BACKED OFF THE TIMING OF PCPN INTO THE AREA SOME.
PREFER LEAVING TUE MOSTLY DRY OUTSIDE OF SHWRS IN THE MTNS DURING
THE DAY. IT ISN/T UNTIL LATER IN THE AFTN THAT SHWRS WILL ENCROACH
UPON THE COAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE IN DECENT AGREEMENT THROUGH LATE IN THE WEEKEND. WE
BEGIN THE PERIOD WITH A SHORTWAVE CROSSING QUEBEC AND AN ASSOCIATED
COLD FRONT CROSSING THE FORECAST AREA. IN THE WAKE OF THIS SYSTEM...A
BUILDING EASTERN RIDGE WITH A DOWNSTREAM UPPER TROUGH OVER THE ROCKIES.
MILD AND INCREASINGLY UNSETTLED THROUGH SATURDAY AS THE UPPER TROUGH
SHEARS OUT AND DRIVES A STRONG COLD FRONT ACROSS THE AREA DURING THE
FIRST HALF OF THE WEEKEND. IN THE DAILIES...HIGH PRESSURE WILL BUILD
SOUTH AND EAST INTO NEW ENGLAND FOR WEDNESDAY AND WEDNESDAY NIGHT.
LOW PRESSURE PASSING TO OUR WEST WILL DRAG A WARM FRONT NORTH ACROSS
THE REGION THURSDAY. A SLOW-MOVING COLD FRONT WILL APPROACH THE
AREA LATE FRIDAY AND FRIDAY NIGHT THEN EXIT THE COAST ON SATURDAY.
HIGH PRESSURE AND DRY AIR BUILDS EAST FROM THE GREAT LAKES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
SHORT TERM...VFR CONDS EXPECTED TO PREVAIL TODAY. IFR OR LOWER
CIGS MAY IMPACT KRKD EARLY THIS MORNING BEFORE SCATTERING OUT THIS
AFTERNOON. PATCHY VALLEY FOG IS PSBL AGAIN BUT NOT AS WIDESPREAD
AS YESTERDAY MORNING. TUE AFTERNOON MVFR CONDS WILL WORK INTO THE
AREA FROM NW TO SE AS COLD FNT APPROACHES. CLOUDS AND SHWRS WILL
CONTINUE WORKING SE THRU THE REST OF THE DAY.
LONG TERM...
TUE - TUE NIGHT...AREAS OF MVFR IN RAIN SHOWERS.
FRI...SCT MVFR IN SHOWERS...WITH LCL IFR POSSIBLE VCNTY OF THE
COAST IN STRATUS AND FOG.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL REMAIN BELOW SCA THRESHOLDS
THRU TONIGHT. WINDS AND SEAS THEN INCREASE AS SWLY FLOW DEVELOPS
AHEAD OF APPROACHING COLD FNT. INVERSION OVER THE WATERS WILL
TEMPER WIND GUSTS SOMEWHAT...BUT SEAS WILL LIKELY BUILD OVER SCA
THRESHOLDS.
LONG TERM...
TUE NIGHT...GALE FORCE WINDS ARE POSSIBLE.
THU NIGHT - FRI...GALE FORCE WINDS ARE POSSIBLE.
&&
.FIRE WEATHER...
FIRE WEATHER DANGER WILL REMAIN LOW TODAY. COOLER...ONSHORE FLOW
WILL KEEP RH VALUES ABOVE 35 PERCENT. TEMPS WARM AND WINDS
INCREASE TUE...BUT THE CHANCE FOR WETTING RAINS WILL ALSO BE ON
THE INCREASE AS A COLD FNT APPROACHES FROM THE NW.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...LEGRO
SHORT TERM...LEGRO
LONG TERM...SCHWIBS
AVIATION...LEGRO/SCHWIBS
MARINE...LEGRO/SCHWIBS
FIRE WEATHER...LEGRO
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
657 AM EDT MON APR 15 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER SOUTHWEST VIRGINIA IS TRACKING
INTO THE MID ATLANTIC REGION THIS MORNING. A COLD FRONT WILL APPROACH THE
AREA TUESDAY BEFORE STALLING OVERHEAD WEDNESDAY. THIS BOUNDARY
WILL RETURN NORTH AS A WARM FRONT THURSDAY BEFORE A STRONGER COLD
FRONT MOVES IN FROM THE WEST LATE FRIDAY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED ON CURRENT OBS/RDR HV INCRSD THE POPS IN THE CENTRAL SHEN
VLLY TO CAT FOR THE MRNG HRS. QPF SHOULD ONLY BE A FEW HUNDRETHS
OF AN INCH BUT THIS IS MORE THAN "CHC" SHOULD BE HANDLING. RA IS
CURRENTLY TRACKING INTO NOVA. POPS WERE INCRSD/NOWCAST IN EFFECT.
PRVS DSCN...
HIGH PRES HAS MOVED FAR ENOUGH OFFSHORE THAT ITS INFLUENCE APPEARS
TO BE WANING IN THE MID ATLC. EVEN THO THE 00Z RNK AND IAD SNDGS
WERE QUITE DRY THIS IS BEING OVERCOME BY MOISTURE W/ THE APRCHG
SHORT WV. AS A RESULT ENTIRE AREA HAS GONE OVC AND THE RAFL ASSO W/
THE UPR LVL SHORT WV HAS PUSHED N OF CHO. BOTH GFS AND NAM ARE
GIVING CHC POPS TO THE ENTIRE RGN TDA...AND HV MADE THAT
ADJUSTMENT W/ THE XCPTN OF LKLY POPS IN THE CENTRAL SHEN VLLY.
QUSTN THEN BECOMES WHAT TIME IS THE BEST FOR MEASURABLE PCPN.
GIVEN CURRENT PCPN MVMNT...AND THE HRRR/LAV PROJECTION FEEL THE
MRNG HRS HV THE BETTER CHC - HRRR IMPLIES THE PCPN BRKG UP THIS
AFTN. REGARDLESS SKIES WL BE CLDY TDA W/ ONLY VERY LOW QPF AMTS.
HIGH TEMPS GNRLY IN M60S XCPT COOLER IN THE HIGHLANDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
CLDY SKIES XPCTD TO CONT TNGT FM THE FLOW OFF THE OCEAN DUE TO THE
HIGH OVR ATLC CANADA. NOT MUCH OF A DIURNAL TEMP SPREAD - LOWS IN
THE LML50S XCPT 40S IN THE HIGHLANDS. PCPN WOULD BE LGT AND
SPOTTY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY BEFORE
MOVING OUT TO SEA TUESDAY NIGHT. A COLD FRONT WILL MOVE THROUGH
PENNSYLVANIA TUESDAY BEFORE MOVING INTO NORTHERN MARYLAND LATE
TUESDAY NIGHT.
AN ONSHORE FLOW AROUND THE SURFACE HIGH WILL CAUSE LOW CLOUDS ALONG
WITH OCCASIONAL DRIZZLE TUESDAY MORNING. THE BEST CHANCE FOR DRIZZLE
WILL BE NORTH AND WEST OF THE I-95 CORRIDOR WHERE THE SUBSIDENCE
INVERSION WILL BE HIGHER. A STRENGTHENING PRESSURE GRADIENT BETWEEN
THE APPROACHING COLD FRONT AND THE DEPARTING HIGH SHOULD CAUSE
ENOUGH OF A GRADIENT TO MIX OUT THE MARINE LAYER TUESDAY AFTERNOON.
THERE SHOULD BE ENOUGH BREAKS OF SUNSHINE FOR MAX TEMPS TO REACH THE
70S ACROSS MOST LOCATIONS. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...WHERE THE
SUBSIDENCE INVERSION WILL BE WEAKEST.
THE COLD FRONT WILL CONTINUE TO DROP SOUTH THROUGH PENNSYLVANIA
TUESDAY EVENING BEFORE MOVING INTO NORTHERN MARYLAND OVERNIGHT. WARM
CONDITIONS ARE EXPECTED AHEAD OF THE BOUNDARY AND SHOWERS ARE
POSSIBLE ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE CWA. MIN
TEMPS WILL RANGE FROM THE MIDDLE 50S IN NORTHERN MARYLAND AND THE
POTOMAC HIGHLANDS TO THE LOWER 60S IN DOWNTOWN WASHINGTON AND
BALTIMORE.
THE COLD FRONT WILL STALL OUT OVER THE REGION WEDNESDAY INTO
THURSDAY BEFORE MOVING NORTH AS A WARM FRONT LATER THURSDAY AND
THURSDAY NIGHT. THE EXACT POSITION OF THE BOUNDARY REMAINS UNCERTAIN
AT THIS TIME WHICH MEANS THAT THERE IS A LOW CERTAINTY IN THE
FORECAST. THE BOUNDARY WILL SEPARATE COOL MARINE AIR TO THE NORTH
AND EAST FROM A WARM AND MOIST AIRMASS TO THE SOUTH AND WEST.
SHOWERS AND T-STORMS ARE POSSIBLE ALONG AND AHEAD OF THE
BOUNDARY...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS EACH
DAY.
A STRONGER COLD FRONT WILL APPROACH THE AREA FRIDAY BEFORE MOVING
THROUGH FRIDAY NIGHT. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG AND AHEAD OF THIS BOUNDARY. THUNDERSTORMS WILL HAVE
THE POTENTIAL TO PRODUCE GUSTY WINDS. CANADIAN HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
OVC SKIES TDA BUT CIGS XPCTD TO RMN ABV LOW VFR LVLS. LGT RA XPCTD
AT TAF SITES THIS MRNG BUT DRY THIS AFTN.
LOW CLOUDS ALONG WITH OCCASIONAL DRIZZLE WILL IMPACT THE
TERMINALS TUESDAY MORNING. IFR CONDITIONS ARE EXPECTED. CIGS/VSBYS
WILL IMPROVE TUESDAY AFTERNOON. A COLD FRONT WILL APPROACH THE
TERMINALS TUESDAY NIGHT BEFORE STALLING OVERHEAD WEDNESDAY INTO
THURSDAY. SHOWERS AND T-STORMS ARE POSSIBLE WEDNESDAY AND
THURSDAY. A STRONGER COLD FRONT WILL APPROACH THE TERMINALS LATER
FRIDAY AND FRIDAY NIGHT. WIDESPREAD SHOWERS/THUNDERSTORMS ARE
POSSIBLE. SOME THUNDERSTORMS MAY CONTAIN GUSTY WINDS.
&&
.MARINE...
MARGINAL SCA IN EFFECT FOR THE AFTN HRS TDA.
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY WHILE A
COLD FRONT APPROACHES FROM PENNSYLVANIA. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE WATERS TUESDAY AND THE SMALL CRAFT ADVISORY MAY BE
NEEDED FOR PORTIONS OF THE WATERS TUESDAY NIGHT. THE COLD FRONT WILL
STALL OVER THE WATERS WEDNESDAY INTO THURSDAY. A STRONGER COLD FRONT
WILL APPROACH THE WATERS FRIDAY BEFORE PASSING THROUGH FRIDAY NIGHT.
SHOWERS AND T-STORMS AHEAD OF THIS BOUNDARY MAY BECOME MORE
WIDESPREAD AND GUSTY WINDS ARE POSSIBLE IN ANY THUNDERSTORMS THAT
DEVELOP.
&&
.TIDES/COASTAL FLOODING...
AT THE MOMENT WATER LVLS IN THE BAY ARE SLTLY ABV NRML...BUT NOT
HIGH ENOUGH TO WARRANT AN ADVSRY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT TUESDAY FOR
ANZ530>543.
&&
$$
PRODUCTS...WOODY!/BJL
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
521 AM EDT MON APR 15 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER SOUTHWEST VIRGINIA IS TRACKING
INTO THE MID ATLANTIC REGION THIS MORNING. A COLD FRONT WILL APPROACH THE
AREA TUESDAY BEFORE STALLING OVERHEAD WEDNESDAY. THIS BOUNDARY
WILL RETURN NORTH AS A WARM FRONT THURSDAY BEFORE A STRONGER COLD
FRONT MOVES IN FROM THE WEST LATE FRIDAY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED ON CURRENT OBS/RDR HV INCRSD THE POPS IN THE CENTRAL SHEN
VLLY TO CAT FOR THE MRNG HRS. QPF SHOULD ONLY BE A FEW HUNDRETHS
OF AN INCH BUT THIS IS MORE THAN "CHC" SHOULD BE HANDLING.
PRVS DSCN...
HIGH PRES HAS MOVED FAR ENOUGH OFFSHORE THAT ITS INFLUENCE APPEARS
TO BE WANING IN THE MID ATLC. EVEN THO THE 00Z RNK AND IAD SNDGS
WERE QUITE DRY THIS IS BEING OVERCOME BY MOISTURE W/ THE APRCHG
SHORT WV. AS A RESULT ENTIRE AREA HAS GONE OVC AND THE RAFL ASSO W/
THE UPR LVL SHORT WV HAS PUSHED N OF CHO. BOTH GFS AND NAM ARE
GIVING CHC POPS TO THE ENTIRE RGN TDA...AND HV MADE THAT
ADJUSTMENT W/ THE XCPTN OF LKLY POPS IN THE CENTRAL SHEN VLLY.
QUSTN THEN BECOMES WHAT TIME IS THE BEST FOR MEASURABLE PCPN.
GIVEN CURRENT PCPN MVMNT...AND THE HRRR/LAV PROJECTION FEEL THE
MRNG HRS HV THE BETTER CHC - HRRR IMPLIES THE PCPN BRKG UP THIS
AFTN. REGARDLESS SKIES WL BE CLDY TDA W/ ONLY VERY LOW QPF AMTS.
HIGH TEMPS GNRLY IN M60S XCPT COOLER IN THE HIGHLANDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
CLDY SKIES XPCTD TO CONT TNGT FM THE FLOW OFF THE OCEAN DUE TO THE
HIGH OVR ATLC CANADA. NOT MUCH OF A DIURNAL TEMP SPREAD - LOWS IN
THE LML50S XCPT 40S IN THE HIGHLANDS. PCPN WOULD BE LGT AND
SPOTTY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY BEFORE
MOVING OUT TO SEA TUESDAY NIGHT. A COLD FRONT WILL MOVE THROUGH
PENNSYLVANIA TUESDAY BEFORE MOVING INTO NORTHERN MARYLAND LATE
TUESDAY NIGHT.
AN ONSHORE FLOW AROUND THE SURFACE HIGH WILL CAUSE LOW CLOUDS ALONG
WITH OCCASIONAL DRIZZLE TUESDAY MORNING. THE BEST CHANCE FOR DRIZZLE
WILL BE NORTH AND WEST OF THE I-95 CORRIDOR WHERE THE SUBSIDENCE
INVERSION WILL BE HIGHER. A STRENGTHENING PRESSURE GRADIENT BETWEEN
THE APPROACHING COLD FRONT AND THE DEPARTING HIGH SHOULD CAUSE
ENOUGH OF A GRADIENT TO MIX OUT THE MARINE LAYER TUESDAY AFTERNOON.
THERE SHOULD BE ENOUGH BREAKS OF SUNSHINE FOR MAX TEMPS TO REACH THE
70S ACROSS MOST LOCATIONS. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...WHERE THE
SUBSIDENCE INVERSION WILL BE WEAKEST.
THE COLD FRONT WILL CONTINUE TO DROP SOUTH THROUGH PENNSYLVANIA
TUESDAY EVENING BEFORE MOVING INTO NORTHERN MARYLAND OVERNIGHT. WARM
CONDITIONS ARE EXPECTED AHEAD OF THE BOUNDARY AND SHOWERS ARE
POSSIBLE ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE CWA. MIN
TEMPS WILL RANGE FROM THE MIDDLE 50S IN NORTHERN MARYLAND AND THE
POTOMAC HIGHLANDS TO THE LOWER 60S IN DOWNTOWN WASHINGTON AND
BALTIMORE.
THE COLD FRONT WILL STALL OUT OVER THE REGION WEDNESDAY INTO
THURSDAY BEFORE MOVING NORTH AS A WARM FRONT LATER THURSDAY AND
THURSDAY NIGHT. THE EXACT POSITION OF THE BOUNDARY REMAINS UNCERTAIN
AT THIS TIME WHICH MEANS THAT THERE IS A LOW CERTAINTY IN THE
FORECAST. THE BOUNDARY WILL SEPARATE COOL MARINE AIR TO THE NORTH
AND EAST FROM A WARM AND MOIST AIRMASS TO THE SOUTH AND WEST.
SHOWERS AND T-STORMS ARE POSSIBLE ALONG AND AHEAD OF THE
BOUNDARY...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS EACH
DAY.
A STRONGER COLD FRONT WILL APPROACH THE AREA FRIDAY BEFORE MOVING
THROUGH FRIDAY NIGHT. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG AND AHEAD OF THIS BOUNDARY. THUNDERSTORMS WILL HAVE
THE POTENTIAL TO PRODUCE GUSTY WINDS. CANADIAN HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
LOW CLOUDS ALONG WITH OCCASIONAL DRIZZLE WILL IMPACT THE TERMINALS
TUESDAY MORNING. IFR CONDITIONS ARE EXPECTED. CIGS/VSBYS WILL
IMPROVE TUESDAY AFTERNOON. A COLD FRONT WILL APPROACH THE TERMINALS
TUESDAY NIGHT BEFORE STALLING OVERHEAD WEDNESDAY INTO THURSDAY.
SHOWERS AND T-STORMS ARE POSSIBLE WEDNESDAY AND THURSDAY. A STRONGER
COLD FRONT WILL APPROACH THE TERMINALS LATER FRIDAY AND FRIDAY
NIGHT. WIDESPREAD SHOWERS/THUNDERSTORMS ARE POSSIBLE. SOME
THUNDERSTORMS MAY CONTAIN GUSTY WINDS.
&&
.MARINE...
MARGINAL SCA IN EFFECT FOR THE AFTN HRS TDA.
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY WHILE A
COLD FRONT APPROACHES FROM PENNSYLVANIA. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE WATERS TUESDAY AND THE SMALL CRAFT ADVISORY MAY BE
NEEDED FOR PORTIONS OF THE WATERS TUESDAY NIGHT. THE COLD FRONT WILL
STALL OVER THE WATERS WEDNESDAY INTO THURSDAY. A STRONGER COLD FRONT
WILL APPROACH THE WATERS FRIDAY BEFORE PASSING THROUGH FRIDAY NIGHT.
SHOWERS AND T-STORMS AHEAD OF THIS BOUNDARY MAY BECOME MORE
WIDESPREAD AND GUSTY WINDS ARE POSSIBLE IN ANY THUNDERSTORMS THAT
DEVELOP.
&&
.TIDES/COASTAL FLOODING...
AT THE MOMENT WATER LVLS IN THE BAY ARE SLTLY ABV NRML...BUT NOT
HIGH ENOUGH TO WARRANT AN ADVSRY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT TUESDAY FOR
ANZ530>543.
&&
$$
PRODUCTS...WOODY!/BJL
AREA FORECAST DISCUSSION
NWS HASTINGS NE
955 AM CDT MON APR 15 2013
.UPDATE...
ISSUED AT 955 AM CDT MON APR 15 2013
A REINFORCING SHOT OF COLD AIR MOVED THRU THE FCST AREA THIS MRNG.
THE FRONTAL INVERSION WAS NEAR 2700 FT ON THE 12Z LBF/OAX
SOUNDINGS. DIFFERENTIAL ADVECTION WAS OCCURRING ABOVE AND BELOW
THE FRONTAL ZONE...WITH WAA IN THE MID-LVLS AHEAD OF A WEAK H7 LOW
OVER CO. THIS WAS THE CAUSE FOR THE RETURNS YOU SEE ON RADAR. ONLY
A FEW FLURRIES MADE IT TO THE GROUND AS THE LOW-LEVELS ARE DRY.
CIGS ARE MOSTLY 8-10K FT.
AS FOR THE FCST EXPECT A MAINLY OVC DAY. SOME BREAKS OR THIN SPOTS
ARE LIKELY WELL SE OF THE TRI-CITIES. SATL SHOWS CLEARING OVER NW
KS AND IT APPEARS TO BE ADVANCING NE. RAP MODEL DOES HAVE THE
TREND SO WILL UPDATE THE FCST TO SHOW SOME IMPROVEMENT WITH
DECREASING CLOUDS S OF HWY 6. WITH THIS IN MIND WILL LEAVE HIGH
TEMPS IN THE MID 50S DOWN THERE AS WELL. WITH OVC EXPECTED TO
REMAIN ALONG AND N OF HWY 6...WILL BE LOWERING HIGH TEMPS 3-6F FOR
OUR NRN COUNTIES.
UPDATE ISSUED AT 825 AM CDT MON APR 15 2013
SENT AN UPDATE TO BETTER REFLECT CURRENT CONDS. THIS INCLUDED
TAKING SKY UP TO OVC. A NOWCAST WAS ISSUED AT 815 AM AND HAVE
INCLUDED SCT FLURRIES IN THE FCST FROM THE TRI-CITIES N AND E.
REFLECTIVITY IS MOVING E AROUND 55 KTS. NEW ECHOES ARE DEVELOPING
W OF THE FCST AREA SO WILL REEVALUATE AS I GET INTO THE SWING OF
THINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON APR 15 2013
TEMPERATURES WILL CONTINUE THEIR DOWNWARD TREND TODAY AS COOLER AIR
CONTINUES TO FILTER IN ACROSS THE REGION BEHIND A SECONDARY COLD
FRONT WHICH SAGGED SOUTHWARD OVERNIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL ANOTHER 10 DEGREES OR SO FROM SUNDAYS
HIGHS.
WHILE SOME CLOUDS ARE STARTING TO FILTER IN ACROSS THE LOCAL
AREA FROM THE WEST THIS MORNING...EXPECT CLOUD COVER TO INCREASE
FURTHER THROUGHOUT THE DAY AS THE NEXT UPPER LEVEL DISTURBANCE
CROSSES THE INTERMOUNTAIN WEST. WHILE BOTH THE 00Z WRF AND 06Z NAM
ARE TRYING TO DEVELOP A BAND OF LIGHT PRECIP ACROSS MUCH OF THE
FORECAST AREA OVERNIGHT TONIGHT...MODELED SOUNDINGS INDICATE A
SIGNIFICANT SPREAD BETWEEN SURFACE TEMPS AND DEWPOINTS THROUGH AT
LEAST THE FIRST HALF OF THE NIGHT...WITH WESTERN AREAS BEGINNING
TO SATURATE AS WE ENTER THE EARLY MORNING HOURS TUESDAY. AS A
RESULT...WENT AHEAD AN TRIMMED BACK POPS A BIT DURING THE EVENING
AND OVERNIGHT HOURS...CONTINUING WITH ONLY SMALL CHANCES FOR SOME
LIGHT RAIN OR SNOW IN AN AREA OF ISENTROPIC LIFT AHEAD OF THIS
NEXT DISTURBANCE. EVEN IF PRECIPITATION IS REALIZED...DO NOT
EXPECT MUCH IN THE WAY OF ACCUMULATION...WITH A FEW HUNDREDTHS OF
LIQUID PRECIP EQUIVALENT AT MOST.
IN ADDITION TO TWEAKING DOWN PRECIP CHANCES SOME OVERNIGHT
TONIGHT...ALSO TWEAKED DOWN LOW TEMPERATURES A BIT TUESDAY MORNING TO
BRING CLOSER TO LATEST GUIDANCE AND TO ACCOUNT FOR THIS COOLER
AIRMASS. OTHERWISE...ONLY A FEW MINOR TWEAKS TO THE WIND/DEWPOINT
GRIDS WERE NECESSARY THIS MORNING...WITH NO SIGNIFICANT WEATHER
IMPACTS EXPECTED THROUGH THE SHORT TERM PERIODS AT THIS TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON APR 15 2013
MAIN FORECAST CONCERNS LIE WITH MID WEEK PRECIPITATION CHANCES...AND
PLENTY OF DETAILS TO IRON OUT BETWEEN MODELS KEEPING CONFIDENCE ON
THE LOWER SIDE.
STARTING OFF THE LONG TERM PERIOD ON TUESDAY...OUTSIDE SOME
LINGERING PRECIPITATION CHANCES DURING THE MORNING ALONG A NARROW
BAND OF MID LEVEL FRONTOGENETICAL FORCING AND ISENTROPIC LIFT...THE
FORECAST IS QUIET...THOUGH WILL HAVE KEEP AN EYE ON THE POTENTIAL
FOR DRIZZLE ACROSS THE SRN PORTIONS OF THE CWA. THE CWA IS SITTING
UNDER SOUTHWESTERLY FLOW IN THE UPPER LEVELS...AHEAD OF ANOTHER
SYSTEM OVER THE ROCKIES...WHICH THROUGH THE DAYTIME HOURS DIGS
FURTHER SOUTH INTO THE ROCKIES. EXPECTING TO SEE EASTERLY WINDS
ACROSS THE CWA AS SFC LOW PRESSURE ORGANIZES OVER THE FOUR CORNERS
REGION. ALONG WITH THE EXPECTED CLOUD COVER AND COOLER AIR MASS IN
PLACE...THINKING HIGH TEMPERATURES IN THE MID 40S LOOKS REASONABLE.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT STILL LOOKING LIKE THE PRIMARY
ACTIVE TIME FRAME OF THE EXTENDED PERIOD...AND EVEN WITH THE EVENT
BEING THIS CLOSE...STILL PLENTY OF VARIATIONS BETWEEN MODELS AND
DETAILS TO IRON OUT. TUESDAY NIGHT...MAIN CONCERN IS PRECIPITATION
POTENTIAL INCREASING...WILL BEGIN TO SEE INCREASING LARGER SCALE
LIFT ACROSS THE REGION AS THE MAIN SYSTEM SHIFT EAST ACROSS THE
ROCKIES...BUT MODELS ARE SHOWING A SRLY LLJ JET NOSING RIGHT INTO
THE CWA. THERE ARE SOME DIFFERENCES BETWEEN MODELS WITH THE
STRENGTH OF THE LLJ...AND WITH THE AMOUNT OF ELEVATED INSTABILITY
AVAILABLE...BUT MENTION OF ISOLATED THUNDER REMAINS IN THE FORECAST
ACROSS SRN PORTIONS OF THE CWA. AS MENTIONED BY PREVIOUS
FORECAST...SOME MODELS CAME IN WARMER AND HAVE REMAINED THAT
WAY...BUT NOT ALL MODELS HAVE. THE ECMWF REMAINS ON THE NOTABLY
COOLER SIDE OF THINGS...5+ DEGREES COOLER IN SOME LOCATIONS. THIS
SOLUTION WOULD BRING A COMPLETE SWITCH OVER TO SNOW TUESDAY NIGHT
FOR A GOOD PORTION OF THE CWA...BUT WITH LITTLE SUPPORT FROM OTHER
MODELS...WILL BE KEEPING PRECIP TYPE AS MAINLY LIQUID WITH A RA/SN
MIX POSSIBLE IN THE NWRN CWA. THIS COOLER ECMWF SOLUTION CONTINUES
THROUGHOUT THE ENTIRE EVENT.
WEDNESDAY...DIDNT MAKE SIGNIFICANT CHANGES TO THE POPS...BUT AM
CONCERNED ABOUT HOW MUCH PRECIPITATION IS ACTUALLY GOING TO BE GOING
ON ONCE THE ACTIVITY FROM OVERNIGHT SLIDES OUT OF THE AREA. MODELS
GENERALLY SHOWING THE SAME BASIC STORY WITH THE MID/UPPER LEVEL
PATTERN THROUGH THE DAYTIME HOURS...CONTINUING ITS EASTWARD SLIDE
AND BY 00Z HAVING AN ELONGATED 700MB LOW ORIENTATED IN A SW/NE LINE
ACROSS WRN PORTIONS OF NEB/KS...WITH A MORE OPEN PATTERN AT 500MB.
AM A LITTLE CONCERNED ABOUT THE 00/06Z NAM RUNS...WHICH BOTH SHOWED
A MORE PRONOUNCED DRY SLOT/BREAK IN PRECIP DURING THE AFTERNOON...BUT
IT IS ALSO MORE ORGANIZED IN THE MID/UPPER LEVELS AND HAS THE LOW
FURTHER N/NE THAN OTHER SOLUTIONS. NOT PUTTING A LOT OF WEIGHT IN
IT...BUT IS SOMETHING TO KEEP AN EYE ON. ANOTHER QUESTION IS WHERE
THE ACCOMPANYING SFC COLD FRONT ENDS UP...AS THIS FRONT WILL PROVIDE
A FOCUS FOR THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON/EVENING
HOURS AS LARGE SCALE LIFT CONTINUES TO INCREASE WITH THE APPROACHING
SYSTEM. THIS TIME ITS THE GFS THAT IS CONCERNING...AS ITS PLACEMENT
OF THE SFC LOW AND FRONTAL BOUNDARY IS FURTHER NORTH THAN THE OTHER
SOLUTIONS...AND IF IT ENDS UP VERIFYING...OUR CWA /ESP THE SRN
PORTIONS/ WOULD BE LOOKING AT A BETTER POTENTIAL FOR
THUNDERSTORMS..INCLUDING SEVERE ONES. AT THIS POINT AM KEEPING THE
FORECAST TRENDED TOWARD THE FURTHER SOUTHWARD PLACEMENT OF THE SFC
FRONT AND ONLY AN ISOLATED MENTION OF THUNDER.
WITH ALL THE VARIATIONS BETWEEN MODELS WITH THE PRECIPITATION
THROUGH THE DAY AND SFC FRONT PLACEMENT...THERE IS A POTENTIAL FOR A
BUST ON AFTERNOON TEMPS...ESP ACROSS THE SOUTHEASTERN HALF. SOME
GUIDANCE/MODELS HAVE HIGHS IN THE 50S/NEAR 60 DEGREES IN THOSE
AREAS...DID BUMP HIGHS A COUPLE DEGREES...BUT WITH SOME MODELS
REMAINING ON THE COOLER SIDE DIDNT WANT TO BUY FULLY INTO THE WARMER
TEMPS QUITE YET.
WEDNESDAY NIGHT/THURSDAY...WHATEVER INSTABILITY THAT IS IN PLACE
OVER THE AREA IS EXPECTED TO QUICKLY FOCUS FURTHER SOUTHEAST OF THE
CWA WEDNESDAY NIGHT...AS THE AXIS OF THE MID/UPPER LEVEL SYSTEM
STARTS TO MOVE FURTHER INTO THE PLAINS...STILL PROVIDING PLENTY OF
LIFT ACROSS THE AREA...BUT BETTER PRECIPITATION CHANCES ARE EXPECTED
TO START SETTING UP OVER ERN PORTIONS OF THE CWA. DID BUMP UP POPS
A TOUCH DURING THE DAY THURSDAY...WITH BETTER AGREEMENT SHOWING THE
SYSTEM A LITTLE SLOWER TO MOVE EAST. MODEL DIFFERENCES WITH THE
THERMAL PROFILE REMAIN IN PLACE...LEAVING SOME QUESTION WITH HOW
QUICKLY A RA/SN MIX OR JUST SN BUILD IN FROM THE WEST. STILL
UNCERTAINTIES WITH ACCUMULATIONS BECAUSE OF THIS ALONG WITH THE
DIFFERENCES IN MODEL QPF ACROSS THE CWA /THE NAM AND SREF HAVE VERY
LITTLE/...BUT THE NORTHWESTERN HALF/THIRD OF THE CWA REMAINS THE
AREA WITH THE BEST POTENTIAL FOR ACCUMULATING SNOWFALL.
LOOKING AT THE FORECAST FOR THURSDAY NIGHT THROUGH
SUNDAY...NORTHWESTERLY FLOW SETS UP IN THE UPPER LEVELS AS THIS MID
WEEK SYSTEM SLIDES FURTHER EAST AND WITH RIDGING OFF THE WEST
COAST. THE FORECAST REMAINS DRY...WITH THE ONE EXCEPTION BEING ON
SUNDAY...WITH MODELS CONTINUING TO SHOW A WEAK UPPER LEVEL
DISTURBANCE SLIDING THROUGH THE REGION. SHOULD BEGIN TO SEE A
REBOUND IN TEMPERATURES...AS THE COLDER AIR SLIDES EAST ALONG WITH
THE MAIN SYSTEM...BUT AT THIS POINT NOT LOOKING AT A SIGNIFICANT WARM
UP...JUST ENOUGH OF ONE TO GET US AT LEAST BACK CLOSER TO AVERAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 605 AM CDT MON APR 15 2013
VFR CONDITIONS WILL PREVAIL AT KGRI FOR THE NEXT 24 HOURS. EXPECT
MID LEVEL CLOUD COVER TO INCREASE ACROSS THE LOCAL AREA OVER THE
NEXT COUPLE OF HOURS...WITH OVERCAST SKIES NEAR OR JUST BELOW
10KFT EXPECTED TO REMAIN THROUGH MOST OF THE PERIOD. NORTHWESTERLY
WINDS WILL INCREASE AROUND DAY BREAK...AND BACK AND BECOME
MORE NORTHERLY LATE IN THE DAY BEHIND A PASSING COLD FRONT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1147 AM MDT MON APR 15 2013
.UPDATE...
ISSUED AT 1147 AM MDT MON APR 15 2013
VERY HEAVY SNOWFALL BEING REPORTED ALONG THE INTERSTATE 70
CORRIDOR FROM RIFLE EAST TO VAIL. CDOT HAS CLOSED PORTIONS OF THE
HIGHWAY DUE TO THE HEAVY SNOW AND REPORTS OF OVER 8 INCHES IN JUST
A FEW HOURS FROM THE GYPSUM AREA. HAVE ADDED ZONE 7...RIFLE
REGION...TO THE WINTER WEATHER ADVISORY AND UPGRADED ZONES 8 AND
10 TO WARNINGS TO DEAL WITH THIS HEAVY WET SNOW AND ENERGETIC
BAND. HAVE CONTINUED TO ADJUST TEMPS DOWNWARD AND ADJUSTED SNOW
LEVELS THROUGH THE REMAINDER OF THE DAY AS THE BAND REMAINS NEARLY
STATIONARY...WITH ALMOST A LIGHT NORTHWARD DRIFT EXPECTED OVER THE
NEXT FEW HOURS.
UPDATE ISSUED AT 912 AM MDT MON APR 15 2013
TEMPS REMAIN COLD ENOUGH ALONG THE INTERSTATE 70 CORRIDOR FROM THE
GLENWOOD CANYON EAST TO VAIL FOR HEAVY SNOW TO CONTINUE FOR A FEW
MORE HOURS. WEB CAMS AND SFC OBS INDICATE POOR CONDITIONS IN THIS
REGION AND ONLY MINOR IMPROVEMENT EXPECTED FOR THE NEXT SEVERAL
HOURS. RAP KEEPS THIS BAND ACTIVE THROUGH THIS AFTERNOON WITH
LITTLE MOVEMENT NORTH OR SOUTH AS THE JET. HAVE CONTINUED TO KNOCK
TEMPS BACK AND EXPAND COVERAGE OF SNOWFALL IN THIS REGION AND
BUMPED THE INTERSTATE 70 CORRIDOR INTO THE GROUPING OF WINTER
WEATHER ADVISORY. WOULD EXPECT A QUICK 2 TO 4 INCHES THIS
MORNING...FOLLOWED BY A MIXED OF RAIN/SNOW THIS AFTERNOON...WITH
ALL SNOW AGAIN TONIGHT.
UPDATE ISSUED AT 840 AM MDT MON APR 15 2013
HAVE UPGRADED ZONES 4 AND 13 TO WINTER STORM WARNINGS THROUGH
EARLY TUESDAY MORNING. BAND OF HEAVIER SNOWFALL WILL CONTINUE TO
IMPACT THE SOUTHERN PORTIONS OF THESE ZONES THROUGH THIS
MORNING...WITH ACTIVITY DIMINISHING A BIT THIS AFTERNOON...BEFORE
THE BAND LIFTS BACK NORTH TONIGHT...PER LATEST RAP RUN. SNOTELS
GENERALLY IN THE 2 TO 6 INCH RANGE SO FAR AND ANTICIPATE LOW END
WARNING LEVELS TO HIT BY LATE TONIGHT. SPOTTER REPORTS IN THE
VICINITY OF STEAMBOAT SPRINGS AND WEB CAMS INDICATE SNOWFALL
APPROACHING ADVISORY LEVELS AND MOST ROADWAYS IN THE AREA REMAIN
ICY AND SNOW PACKED. MADE SOME ADJUSTMENTS TO TEMPS AND BOOSTED
SNOWFALL AMOUNTS THROUGH LATE TONIGHT IN THE STEAMBOAT SPRINGS
AREA AND ALSO UPGRADED THEM TO AN ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
ANOTHER CHALLENGING STORM GREETS THE NEW WORKWEEK. SNOW HAS
INCREASED ACROSS NE UT/NW CO EARLY THIS MORNING IN ISENTROPIC AND
DYNAMIC UPLIFT AHEAD OF THE NEXT SHORTWAVE/UPPER JET MAX. 400 AM
WEB CAM PICS INDICATED GROUND WARMTH KEEPING ROADS WET AT VERNAL THOUGH
AIR TEMPS HAVE DROPPED BELOW FREEZING...AND SNOW WAS JUST BEGINNING
TO STICK TO THE PAVEMENT AT STEAMBOAT. BOTH NAM AND GFS SHOW A GOOD
COMBINATION OF UPPER DIVERGENCE... FRONTOGENETIC FORCING ALONG AN
EAST-WEST ORIENTED BAROCLINIC ZONE AT 700 MB...AND MOIST ISENTROPIC
UPGLIDE THROUGH THE MORNING ACROSS THE NORTH. TIME-HEIGHT SECTIONS
OF -PVU ALSO INDICATE THE POSSIBLY OF SOME BANDED PRECIPITATION FOR
LOCALLY HEAVIER PRECIP...JUST DIFFICULT TO PINPOINT EXACTLY WHERE.
RAPID REFRESH MODEL SHOWED PRECIP TAPERING OFF IN THE NORTHERN
VALLEYS LATER THIS MORNING...BUT WILL STILL HAVE MONITOR SNOW
ACCUMULATION FOR THESE NORTHERN VALLEYS AS SOME LOWER ELEVATION
LOCATIONS MAY SEE A COUPLE INCHES BEFORE TEMPS WARM SUFFICIENTLY.
MAIN CHALLENGE TODAY THROUGH TUESDAY IS SNOW ACCUMS AND LOCATION OF
THE HEAVIER AMTS. BEST PERIOD MAY BE TODAY GIVEN THE COMBINATION OF
FORCING PREVIOUSLY MENTIONED...BUT SOME UNCERTAINTY IN LOCATION WITH
THE NAM FAVORING THE NRN MTNS WHILE THE GFS MORE THE CENTRAL MTNS.
FOR CO ZONE 4 /ELKHEAD AND PARK MTNS/ FLOW TURNS FROM WESTERLY TO
LESS FAVORABLE SOUTHERLY TONIGHT IN RESPONSE TO A DEEPENING TROUGH
OVER NEVADA...BUT CONTINUED DYNAMIC AND ISENTROPIC FORCING SHOULD
COMPENSATE SOMEWHAT. WILL KEEP THE CURRENT WINTER WEATHER ADVISORIES
FOR THE NORTHERN AND CENTRAL MTNS INTACT THOUGH DAY SHIFT WILL HAVE
TO MONITOR FOR ANY UPGRADE TO WARNING.
AS PACIFIC ENERGY OFF THE WA/OR COAST DEVELOP A COLD TROUGH OVER THE
GREAT BASIN BY TUESDAY AFTERNOON...THE UPPER JET AND BAROCLINIC ZONE
ACROSS THE NORTH SHOULD ROTATE COUNTERCLOCKWISE...WITH THE PIVOT
POINT NEAR NE UT. SURFACE LOW DEVELOPS OVER SE UT TUE MORNING AND
SHIFTS INTO SW CO TUE AFTERNOON AS 700 MB LOW MOVES OVER NE UT.
DRYING IS NOT AS PRONOUNCED IN THE WARM SECTOR ACROSS WRN CO AS
EARLIER MODELS INDICATED...SO WILL KEEP SCATTERED TO NUMEROUS
SHOWERS ACROSS THE NORTH BUT WITH LESSER ACCUMULATIONS.
GUSTY WINDS ARE EXPECTED ACROSS SE UT/SW CO TODAY AND TUESDAY. GUSTS
UP TO 40 MPH ARE POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
STRONGEST DEEP LAYERED ASCENT OCCURS TUESDAY NIGHT INTO WEDNESDAY
MORNING ACROSS THE ENTIRE FORECAST AREA...BUT THE BEST QG FORCING
WILL BE CENTERED OVER THE NORTHEAST PORTION OF THE FORECAST AREA.
FAIRLY STRONG MID LEVEL COLD ADVECTION WHERE 700 MB TEMPS BECOME
COLDER THAN -10C ON THE BACK SIDE OF THE TROUGH...SUGGESTING THAT
SNOW PRODUCTION BECOMES MORE EFFICIENT AS THE COLDER SPREADS ACROSS
THE WRN SLOPE. DEEP COLD TROUGH IS MORE ELONGATED...AND THIS IS A
FORECAST CONCERN AS THE OROGRAPHIC COMPONENT WILL BE LESS FAVORABLE
(BECOMING NORTHERLY INSTEAD OF THE PREFERRED POST FRONTAL NORTHWEST
FLOW). ONE STRONG PLUS IS THE 700 MB LOW MOVES ACROSS WRN COLORADO
WITH GOOD MOISTURE CONVERGENCE...AND THAT WILL LEAD TO ROBOST
SNOWFALL RATES AS THE FRONT MOVES ACROSS THE AREA. WILL HOIST A
WINTER STORM WATCH FOR TUESDAY NIGHT THROUGH WEDNESDAY FOR THE WRN
COLORADO HIGH COUNTRY...ALTHOUGH CONFIDENCE IS ONLY 50/50 GIVEN THE
AFOREMENTIONED TROUGH STRUCTURE. THIS COULD EVOLVE INTO THE TYPE OF
STORM WHERE ONE LOCATION RECEIVES A HEALTHY DOSE OF SNOW...AND A FEW
MILES AWAY WITH DIFFERENT TERRAIN GETS SKUNKED. DAGGETT COUNTY IS
ONE AREA THAT COULD RECEIVE HEAVY AMOUNTS...AND LATER SHIFTS MAY
NEED TO CONSIDER UPGRADING THE WINTER WEATHER ADVISORY TO A
WARNING. THE UNCOMPAHGRE GORGE IS ANOTHER LOCATION THAT MAY BE
ANOTHER TROUBLE SPOT.
MOISTURE DROPS OFF FAIRLY QUICKLY THURSDAY NIGHT AS THE MAIN UPPER
LOW MOVES INTO THE CENTRAL PLAINS. LIGHT OROGRAPHIC SNOW MAY LINGER
TOWARD THE DIVIDE...OTHERWISE CLEARING CONDITIONS FROM THE WEST.
FROSTY CONDITIONS WITH WELL BELOW NORMAL TEMPS THAT POSE A THREAT TO
SENSITIVE VEGETATION.
FRIDAY THROUGH SUNDAY...NORTHWEST FLOW PREVAILS WITH EMBEDDED
PROGRESSIVE SHORT WAVES. ONE FAST MOVING WAVE SKIRTS THE NRN DIVIDE
ON FRIDAY...BUT THE STRONGEST OPEN WAVE SPREADS DECENT PACIFIC
MOISTURE ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY AND HAS THE
POTENTIAL TO DROP SEVERAL INCHES OF SNOW OVER THE NRN MOUNTAINS.
OTHERWISE TEMPS WILL BE MODERATING THIS WEEKEND AND SLOWLY CLIMB TO
NEAR CLIMO BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED
AT 912 AM MDT MON APR 15 2013
IFR CONDITIONS IN -SN/SN AND BR WILL BE WIDESPREAD FROM I-70
NORTHWARD THROUGH TONIGHT. THIS INCLUDES KVEL...KRIL...KEGE AND
KASE. THE CENTRAL AND SOUTHERN MOUNTAINS WILL BE OCCASIONALLY OBSCURED
IN -SN. EXPECTED DEGRADED FLIGHT CONDITIONS FOR THE NORTH AND
CENTRAL AREAS THROUGH 18Z TUE. STRONG GUSTY WINDS WILL HAMPER
AVIATION OPERATIONS IN SE UT AND SW CO THIS AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MDT TUESDAY FOR COZ003-005-
007-009-012.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR COZ003-004-009-010-012-013-018.
WINTER STORM WARNING UNTIL 9 AM MDT TUESDAY FOR COZ004-008-010-
013.
UT...WINTER WEATHER ADVISORY UNTIL 6 PM MDT WEDNESDAY FOR UTZ023.
&&
$$
UPDATE...JDC
SHORT TERM...JAD
LONG TERM...PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
914 AM MDT MON APR 15 2013
.UPDATE...
ISSUED AT 912 AM MDT MON APR 15 2013
TEMPS REMAIN COLD ENOUGH ALONG THE INTERSTATE 70 CORRIDOR FROM THE
GLENWOOD CANYON EAST TO VAIL FOR HEAVY SNOW TO CONTINUE FOR A FEW
MORE HOURS. WEB CAMS AND SFC OBS INDICATE POOR CONDITIONS IN THIS
REGION AND ONLY MINOR IMPROVEMENT EXPECTED FOR THE NEXT SEVERAL
HOURS. RAP KEEPS THIS BAND ACTIVE THROUGH THIS AFTERNOON WITH
LITTLE MOVEMENT NORTH OR SOUTH AS THE JET. HAVE CONTINUED TO KNOCK
TEMPS BACK AND EXPAND COVERAGE OF SNOWFALL IN THIS REGION AND
BUMPED THE INTERSTATE 70 CORRIDOR INTO THE GROUPING OF WINTER
WEATHER ADVISORY. WOULD EXPECT A QUICK 2 TO 4 INCHES THIS
MORNING...FOLLOWED BY A MIXED OF RAIN/SNOW THIS AFTERNOON...WITH
ALL SNOW AGAIN TONIGHT.
UPDATE ISSUED AT 840 AM MDT MON APR 15 2013
HAVE UPGRADED ZONES 4 AND 13 TO WINTER STORM WARNINGS THROUGH
EARLY TUESDAY MORNING. BAND OF HEAVIER SNOWFALL WILL CONTINUE TO
IMPACT THE SOUTHERN PORTIONS OF THESE ZONES THROUGH THIS
MORNING...WITH ACTIVITY DIMINISHING A BIT THIS AFTERNOON...BEFORE
THE BAND LIFTS BACK NORTH TONIGHT...PER LATEST RAP RUN. SNOTELS
GENERALLY IN THE 2 TO 6 INCH RANGE SO FAR AND ANTICIPATE LOW END
WARNING LEVELS TO HIT BY LATE TONIGHT. SPOTTER REPORTS IN THE
VICINITY OF STEAMBOAT SPRINGS AND WEB CAMS INDICATE SNOWFALL
APPROACHING ADVISORY LEVELS AND MOST ROADWAYS IN THE AREA REMAIN
ICY AND SNOW PACKED. MADE SOME ADJUSTMENTS TO TEMPS AND BOOSTED
SNOWFALL AMOUNTS THROUGH LATE TONIGHT IN THE STEAMBOAT SPRINGS
AREA AND ALSO UPGRADED THEM TO AN ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
ANOTHER CHALLENGING STORM GREETS THE NEW WORKWEEK. SNOW HAS
INCREASED ACROSS NE UT/NW CO EARLY THIS MORNING IN ISENTROPIC AND
DYNAMIC UPLIFT AHEAD OF THE NEXT SHORTWAVE/UPPER JET MAX. 400 AM
WEB CAM PICS INDICATED GROUND WARMTH KEEPING ROADS WET AT VERNAL THOUGH
AIR TEMPS HAVE DROPPED BELOW FREEZING...AND SNOW WAS JUST BEGINNING
TO STICK TO THE PAVEMENT AT STEAMBOAT. BOTH NAM AND GFS SHOW A GOOD
COMBINATION OF UPPER DIVERGENCE... FRONTOGENETIC FORCING ALONG AN
EAST-WEST ORIENTED BAROCLINIC ZONE AT 700 MB...AND MOIST ISENTROPIC
UPGLIDE THROUGH THE MORNING ACROSS THE NORTH. TIME-HEIGHT SECTIONS
OF -PVU ALSO INDICATE THE POSSIBLY OF SOME BANDED PRECIPITATION FOR
LOCALLY HEAVIER PRECIP...JUST DIFFICULT TO PINPOINT EXACTLY WHERE.
RAPID REFRESH MODEL SHOWED PRECIP TAPERING OFF IN THE NORTHERN
VALLEYS LATER THIS MORNING...BUT WILL STILL HAVE MONITOR SNOW
ACCUMULATION FOR THESE NORTHERN VALLEYS AS SOME LOWER ELEVATION
LOCATIONS MAY SEE A COUPLE INCHES BEFORE TEMPS WARM SUFFICIENTLY.
MAIN CHALLENGE TODAY THROUGH TUESDAY IS SNOW ACCUMS AND LOCATION OF
THE HEAVIER AMTS. BEST PERIOD MAY BE TODAY GIVEN THE COMBINATION OF
FORCING PREVIOUSLY MENTIONED...BUT SOME UNCERTAINTY IN LOCATION WITH
THE NAM FAVORING THE NRN MTNS WHILE THE GFS MORE THE CENTRAL MTNS.
FOR CO ZONE 4 /ELKHEAD AND PARK MTNS/ FLOW TURNS FROM WESTERLY TO
LESS FAVORABLE SOUTHERLY TONIGHT IN RESPONSE TO A DEEPENING TROUGH
OVER NEVADA...BUT CONTINUED DYNAMIC AND ISENTROPIC FORCING SHOULD
COMPENSATE SOMEWHAT. WILL KEEP THE CURRENT WINTER WEATHER ADVISORIES
FOR THE NORTHERN AND CENTRAL MTNS INTACT THOUGH DAY SHIFT WILL HAVE
TO MONITOR FOR ANY UPGRADE TO WARNING.
AS PACIFIC ENERGY OFF THE WA/OR COAST DEVELOP A COLD TROUGH OVER THE
GREAT BASIN BY TUESDAY AFTERNOON...THE UPPER JET AND BAROCLINIC ZONE
ACROSS THE NORTH SHOULD ROTATE COUNTERCLOCKWISE...WITH THE PIVOT
POINT NEAR NE UT. SURFACE LOW DEVELOPS OVER SE UT TUE MORNING AND
SHIFTS INTO SW CO TUE AFTERNOON AS 700 MB LOW MOVES OVER NE UT.
DRYING IS NOT AS PRONOUNCED IN THE WARM SECTOR ACROSS WRN CO AS
EARLIER MODELS INDICATED...SO WILL KEEP SCATTERED TO NUMEROUS
SHOWERS ACROSS THE NORTH BUT WITH LESSER ACCUMULATIONS.
GUSTY WINDS ARE EXPECTED ACROSS SE UT/SW CO TODAY AND TUESDAY. GUSTS
UP TO 40 MPH ARE POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
STRONGEST DEEP LAYERED ASCENT OCCURS TUESDAY NIGHT INTO WEDNESDAY
MORNING ACROSS THE ENTIRE FORECAST AREA...BUT THE BEST QG FORCING
WILL BE CENTERED OVER THE NORTHEAST PORTION OF THE FORECAST AREA.
FAIRLY STRONG MID LEVEL COLD ADVECTION WHERE 700 MB TEMPS BECOME
COLDER THAN -10C ON THE BACK SIDE OF THE TROUGH...SUGGESTING THAT
SNOW PRODUCTION BECOMES MORE EFFICIENT AS THE COLDER SPREADS ACROSS
THE WRN SLOPE. DEEP COLD TROUGH IS MORE ELONGATED...AND THIS IS A
FORECAST CONCERN AS THE OROGRAPHIC COMPONENT WILL BE LESS FAVORABLE
(BECOMING NORTHERLY INSTEAD OF THE PREFERRED POST FRONTAL NORTHWEST
FLOW). ONE STRONG PLUS IS THE 700 MB LOW MOVES ACROSS WRN COLORADO
WITH GOOD MOISTURE CONVERGENCE...AND THAT WILL LEAD TO ROBOST
SNOWFALL RATES AS THE FRONT MOVES ACROSS THE AREA. WILL HOIST A
WINTER STORM WATCH FOR TUESDAY NIGHT THROUGH WEDNESDAY FOR THE WRN
COLORADO HIGH COUNTRY...ALTHOUGH CONFIDENCE IS ONLY 50/50 GIVEN THE
AFOREMENTIONED TROUGH STRUCTURE. THIS COULD EVOLVE INTO THE TYPE OF
STORM WHERE ONE LOCATION RECEIVES A HEALTHY DOSE OF SNOW...AND A FEW
MILES AWAY WITH DIFFERENT TERRAIN GETS SKUNKED. DAGGETT COUNTY IS
ONE AREA THAT COULD RECEIVE HEAVY AMOUNTS...AND LATER SHIFTS MAY
NEED TO CONSIDER UPGRADING THE WINTER WEATHER ADVISORY TO A
WARNING. THE UNCOMPAHGRE GORGE IS ANOTHER LOCATION THAT MAY BE
ANOTHER TROUBLE SPOT.
MOISTURE DROPS OFF FAIRLY QUICKLY THURSDAY NIGHT AS THE MAIN UPPER
LOW MOVES INTO THE CENTRAL PLAINS. LIGHT OROGRAPHIC SNOW MAY LINGER
TOWARD THE DIVIDE...OTHERWISE CLEARING CONDITIONS FROM THE WEST.
FROSTY CONDITIONS WITH WELL BELOW NORMAL TEMPS THAT POSE A THREAT TO
SENSITIVE VEGETATION.
FRIDAY THROUGH SUNDAY...NORTHWEST FLOW PREVAILS WITH EMBEDDED
PROGRESSIVE SHORT WAVES. ONE FAST MOVING WAVE SKIRTS THE NRN DIVIDE
ON FRIDAY...BUT THE STRONGEST OPEN WAVE SPREADS DECENT PACIFIC
MOISTURE ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY AND HAS THE
POTENTIAL TO DROP SEVERAL INCHES OF SNOW OVER THE NRN MOUNTAINS.
OTHERWISE TEMPS WILL BE MODERATING THIS WEEKEND AND SLOWLY CLIMB TO
NEAR CLIMO BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED
AT 912 AM MDT MON APR 15 2013
IFR CONDITIONS IN -SN/SN AND BR WILL BE WIDESPREAD FROM I-70
NORTHWARD THROUGH TONIGHT. THIS INCLUDES KVEL...KRIL...KEGE AND
KASE. THE CENTRAL AND SOUTHERN MOUNTAINS WILL BE OCCASIONALLY OBSCURED
IN -SN. EXPECTED DEGRADED FLIGHT CONDITIONS FOR THE NORTH AND
CENTRAL AREAS THROUGH 18Z TUE. STRONG GUSTY WINDS WILL HAMPER
AVIATION OPERATIONS IN SE UT AND SW CO THIS AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MDT TUESDAY FOR COZ005-
008>010-012.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR COZ003-004-009-010-012-013-018.
WINTER STORM WARNING UNTIL 9 AM MDT TUESDAY FOR COZ004-013.
UT...WINTER WEATHER ADVISORY UNTIL 6 PM MDT WEDNESDAY FOR UTZ023.
&&
$$
UPDATE...JDC
SHORT TERM...JAD
LONG TERM...PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
840 AM MDT MON APR 15 2013
.UPDATE...
ISSUED AT 840 AM MDT MON APR 15 2013
HAVE UPGRADED ZONES 4 AND 13 TO WINTER STORM WARNINGS THROUGH
EARLY TUESDAY MORNING. BAND OF HEAVIER SNOWFALL WILL CONTINUE TO
IMPACT THE SOUTHERN PORTIONS OF THESE ZONES THROUGH THIS
MORNING...WITH ACTIVITY DIMINISHING A BIT THIS AFTERNOON...BEFORE
THE BAND LIFTS BACK NORTH TONIGHT...PER LATEST RAP RUN. SNOTELS
GENERALLY IN THE 2 TO 6 INCH RANGE SO FAR AND ANTICIPATE LOW END
WARNING LEVELS TO HIT BY LATE TONIGHT. SPOTTER REPORTS IN THE
VICINITY OF STEAMBOAT SPRINGS AND WEB CAMS INDICATE SNOWFALL
APPROACHING ADVISORY LEVELS AND MOST ROADWAYS IN THE AREA REMAIN
ICY AND SNOWPACKED. MADE SOME ADJUSTMENTS TO TEMPS AND BOOSTED
SNOWFALL AMOUNTS THROUGH LATE TONIGHT IN THE STEAMBOAT SPRINGS
AREA AND ALSO UPGRADED THEM TO AN ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
ANOTHER CHALLENGING STORM GREETS THE NEW WORKWEEK. SNOW HAS
INCREASED ACROSS NE UT/NW CO EARLY THIS MORNING IN ISENTROPIC AND
DYNAMIC UPLIFT AHEAD OF THE NEXT SHORTWAVE/UPPER JET MAX. 400 AM
WEBCAM PICS INDICATED GROUND WARMTH KEEPING ROADS WET AT VERNAL THOUGH
AIR TEMPS HAVE DROPPED BELOW FREEZING...AND SNOW WAS JUST BEGINNING
TO STICK TO THE PAVEMENT AT STEAMBOAT. BOTH NAM AND GFS SHOW A GOOD
COMBINATION OF UPPER DIVERGENCE... FRONTOGENETIC FORCING ALONG AN
EAST-WEST ORIENTED BAROCLINIC ZONE AT 700 MB...AND MOIST ISENTROPIC
UPGLIDE THROUGH THE MORNING ACROSS THE NORTH. TIME-HEIGHT SECTIONS
OF -PVU ALSO INDICATE THE POSSIBLY OF SOME BANDED PRECIPITATION FOR
LOCALLY HEAVIER PRECIP...JUST DIFFICULT TO PINPOINT EXACTLY WHERE.
RAPID REFRESH MODEL SHOWED PRECIP TAPERING OFF IN THE NORTHERN
VALLEYS LATER THIS MORNING...BUT WILL STILL HAVE MONITOR SNOW
ACCUMULATION FOR THESE NORTHERN VALLEYS AS SOME LOWER ELEVATION
LOCATIONS MAY SEE A COUPLE INCHES BEFORE TEMPS WARM SUFFICIENTLY.
MAIN CHALLENGE TODAY THROUGH TUESDAY IS SNOW ACCUMS AND LOCATION OF
THE HEAVIER AMTS. BEST PERIOD MAY BE TODAY GIVEN THE COMBINATION OF
FORCING PREVIOUSLY MENTIONED...BUT SOME UNCERTAINTY IN LOCATION WITH
THE NAM FAVORING THE NRN MTNS WHILE THE GFS MORE THE CENTRAL MTNS.
FOR CO ZONE 4 /ELKHEAD AND PARK MTNS/ FLOW TURNS FROM WESTERLY TO
LESS FAVORABLE SOUTHERLY TONIGHT IN RESPONSE TO A DEEPENING TROUGH
OVER NEVADA...BUT CONTINUED DYNAMIC AND ISENTROPIC FORCING SHOULD
COMPENSATE SOMEWHAT. WILL KEEP THE CURRENT WINTER WEATHER ADVISORIES
FOR THE NORTHERN AND CENTRAL MTNS INTACT THOUGH DAYSHIFT WILL HAVE
TO MONITOR FOR ANY UPGRADE TO WARNING.
AS PACIFIC ENERGY OFF THE WA/OR COAST DEVELOP A COLD TROUGH OVER THE
GREAT BASIN BY TUESDAY AFTERNOON...THE UPPER JET AND BAROCLINIC ZONE
ACROSS THE NORTH SHOULD ROTATE COUNTERCLOCKWISE...WITH THE PIVOT
POINT NEAR NE UT. SURFACE LOW DEVELOPS OVER SE UT TUE MORNING AND
SHIFTS INTO SW CO TUE AFTERNOON AS 700 MB LOW MOVES OVER NE UT.
DRYING IS NOT AS PRONOUNCED IN THE WARM SECTOR ACROSS WRN CO AS
EARLIER MODELS INDICATED...SO WILL KEEP SCATTERED TO NUMEROUS
SHOWERS ACROSS THE NORTH BUT WITH LESSER ACCUMULATIONS.
GUSTY WINDS ARE EXPECTED ACROSS SE UT/SW CO TODAY AND TUESDAY. GUSTS
UP TO 40 MPH ARE POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
STRONGEST DEEP LAYERED ASCENT OCCURS TUESDAY NIGHT INTO WEDNESDAY
MORNING ACROSS THE ENTIRE FORECAST AREA...BUT THE BEST QG FORCING
WILL BE CENTERED OVER THE NORTHEAST PORTION OF THE FORECAST AREA.
FAIRLY STRONG MID LEVEL COLD ADVECTION WHERE 700 MB TEMPS BECOME
COLDER THAN -10C ON THE BACK SIDE OF THE TROUGH...SUGGESTING THAT
SNOW PRODUCTION BECOMES MORE EFFICIENT AS THE COLDER SPREADS ACROSS
THE WRN SLOPE. DEEP COLD TROUGH IS MORE ELONGATED...AND THIS IS A
FORECAST CONCERN AS THE OROGRAPHIC COMPONENT WILL BE LESS FAVORABLE
(BECOMING NORTHERLY INSTEAD OF THE PREFERRED POST FRONTAL NORTHWEST
FLOW). ONE STRONG PLUS IS THE 700 MB LOW MOVES ACROSS WRN COLORADO
WITH GOOD MOISTURE CONVERGENCE...AND THAT WILL LEAD TO ROBOST
SNOWFALL RATES AS THE FRONT MOVES ACROSS THE AREA. WILL HOIST A
WINTER STORM WATCH FOR TUESDAY NIGHT THROUGH WEDNESDAY FOR THE WRN
COLORADO HIGH COUNTRY...ALTHOUGH CONFIDENCE IS ONLY 50/50 GIVEN THE
AFOREMENTIONED TROUGH STRUCTURE. THIS COULD EVOLVE INTO THE TYPE OF
STORM WHERE ONE LOCATION RECEIVES A HEALTHY DOSE OF SNOW...AND A FEW
MILES AWAY WITH DIFFERENT TERRAIN GETS SKUNKED. DAGGETT COOUNTY IS
ONE AREA THAT COULD RECEIVE HEAVY AMOUNTS...AND LATER SHIFTS MAY
NEED TO CONSIDER UPGRADING THE WINTER WEATHER ADVISORY TO A
WARNING. THE UNCOMPAHGRE GORGE IS ANOTHER LOCATION THAT MAY BE
ANOTHER TROUBLE SPOT.
MOISTURE DROPS OFF FAIRLY QUICKLY THURSDAY NIGHT AS THE MAIN UPPER
LOW MOVES INTO THE CENTRAL PLAINS. LIGHT OROGRAPHIC SNOW MAY LINGER
TOWARD THE DIVIDE...OTHERWISE CLEARING CONDITIONS FROM THE WEST.
FROSTY CONDITIONS WITH WELL BELOW NORMAL TEMPS THAT POSE A THREAT TO
SENSITIVE VEGETATION.
FRIDAY THROUGH SUNDAY...NORTHWEST FLOW PREVAILS WITH EMBEDDED
PROGRESSIVE SHORT WAVES. ONE FAST MOVING WAVE SKIRTS THE NRN DIVIDE
ON FRIDAY...BUT THE STRONGEST OPEN WAVE SPREADS DECENT PACIFIC
MOISTURE ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY AND HAS THE
POTENTIAL TO DROP SEVERAL INCHES OF SNOW OVER THE NRN MOUNTAINS.
OTHERWISE TEMPS WILL BE MODERATING THIS WEEKEND AND SLOWLY CLIMB TO
NEAR CLIMO BY SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 507 AM MDT MON APR 15 2013
IFR CONDITIONS IN -SN/SN AND BR WILL BE WIDESPREAD FROM I-70
NORTHWARD THIS MORNING WITH MOUNTAINS OBSCURED. THIS INCLUDES
KVEL...KRIL...KEGE AND KASE. SOME IMPROVEMENT IS EXPECTED BY
MIDDAY...BUT -SHSN/-SHRA THROUGH THE AFTERNOON WILL CONTINUE. THE
CENTRAL AND SOUTHERN MOUNTAINS WILL BE OCCASIONALLY BE OBSCURED IN
-SN. EXPECTED DEGRADED FLIGHT CONDITIONS FOR THE NORTH AND CENTRAL
AREAS THROUGH 12Z TUE. STRONG GUSTY WINDS WILL HAMPER AVIATION
OPERATIONS IN SE UT AND SW CO THIS AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MDT TUESDAY FOR COZ005-009-
010-012.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR COZ003-004-009-010-012-013-018.
WINTER STORM WARNING UNTIL 9 AM MDT TUESDAY FOR COZ004-013.
UT...WINTER WEATHER ADVISORY UNTIL 6 PM MDT WEDNESDAY FOR UTZ023.
&&
$$
UPDATE...JDC
SHORT TERM...JAD
LONG TERM...PF
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
452 PM EDT MON APR 15 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 420 PM EDT MON APR 15 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR TROF
STRETCHING FM MN THRU THE PAC NW UPSTREAM OF UPR RDG OVER THE ERN
CONUS. SHRTWV THAT CAUSED WINTRY MIX OF PCPN SUN INTO THIS MRNG IS
LIFTING NEWD THRU MN ON THE ERN FLANK OF THE UPR TROF AXIS. DRY SLOT
ON THE ERN FLANK OF THIS DISTURBANCE HAS ADVECTED MUCH DRIER MID LVL
AIR OVER UPR MI WITH SW H7 WINDS UP TO 73 KTS AS SHOWN ON THE 12Z
GRB RAOB. SINCE WARM CONVEYOR BELT MSTR HAS ALSO SHIFTED TO THE E...
THE CWA IS PCPN FREE THIS AFTN. RETURN OF SUNSHINE UNDER THE DRY
SLOTTING OVER THE W AND CENTRAL HAS CAUSED TEMPS TO RECOVER TO MORE
SEASONABLE LVLS. OVER THE E...LO CLDS HAVE BEEN MORE PERSISTENT WITH
SSW LLVL FLOW OFF THE CHILLY LK MI WATERS AND LLVL MSTR SHOWN ON THE
12Z GRB RAOB. BKN SC HAS ALSO DVLPD OVER THE W AS DAYTIME HEATING
HAS DESTABILIZED LLVL LAPSE RATES WITH INFLUX OF LOWER H85 TEMPS AND
ARRIVAL OF MOISTER LLVL AIR DEPICTED ON THE 12Z MPX RAOB.
TNGT...SHRTWV/SFC LO IN MN ARE PROGGED TO SHIFT NEWD THRU NW
ONTARIO. ALTHOUGH SUPPORTING DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL
SLIDE TO THE NW OF UPR MI...THERE MAY BE ENUF MOISTENING OVER THE W
WITH THE SLOW ARRIVAL OF COLDER AIR TO JUSTIFY RETAINING FCST OF
SCHC POPS IN THAT AREA...ESPECIALLY OVERNGT WITH A WSHFT TO AN
UPSLOPE W COMPONENT COINCIDENT WITH LO PRES TROF PASSAGE TO THE S OF
LO MOVING THRU NW ONTARIO. ALTHOUGH THERE MAY BE MORE SC OVER THE CNTRL AS
WELL...THE TRANSITION TO A MORE W WIND SHOULD AID CLRG OVER THE E.
TUE...LO PRES TROF ON THE SW FLANK OF DEPARTING SHRTWV/SFC LO TOWARD
JAMES BAY WL CROSS UPR MI BY EARLY AFTN. ALTHOUGH THERE WL LIKELY BE
QUITE A BIT OF SC IN THE MOIST CYC W-SW SHIFTING NW FLOW...SHARP INVRN
NEAR H8 SHOWN ON FCST SDNGS IN THE ABSENCE OF ANY UPR SUPPORT WL
SQUASH POPS AWAY FM THE W...WHERE UPSLOPE FLOW MIGHT GENERATE A FEW
-SHSN IN THE MRNG. AS THE LLVL FLOW TRENDS MORE ACYC DURING THE AFTN
FOLLOWING THE TROF PASSAGE AND SE OF HI PRES BLDG TOWARD NW
ONTARIO...THE SC MAY TEND TO BREAK UP IN THE AFTN...ESPECIALLY
DOWNWIND OF LK SUP WITH SPRING STABILIZATION IN THE AFTN OFF THE
WATER. DEEP MIXING TO H8-85 WL SUPPORT MAX TEMPS APRCHG 50 OVER THE
SCENTRAL WITH DOWNSLOPE NW FLOW. AREAS NEAR LK SUP WL BE COOLER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 451 PM EDT MON APR 15 2013
THERE ARE A COUPLE OF PERIODS OF CONCERN IN THIS LONG TERM PERIOD.
THE FIRST WILL PUSH IN FROM THE SOUTHWEST WEDNESDAY EVENING THROUGH
THURSDAY MORNING...WITH A SECONDARY SURGE OF MOISTURE SLIDING ACROSS
UPPER MICHIGAN THURSDAY NIGHT INTO FRIDAY. LATE THIS WEEKEND INTO
EARLY NEXT WEEK MAY ALSO END UP BEING INTERESTING...WITH ANOTHER
SURGE OF WARM AIR PUSHES IN FROM THE SOUTH.
AT 00Z WEDNESDAY A WEAK SFC TROUGH MAY STILL BE OVER CENTRAL LAKE
SUPERIOR AND NORTHERN UPPER MICHIGAN...BUT THAT FEATURE SHOULD EXIT
QUICKLY AS THE LARGE AREA OF HIGH PRESSURE OVER CENTRAL CANADA
PUSHES INTO ONTARIO AND LAKE SUPERIOR OVERNIGHT. KEPT CONDITIONS DRY
FOR NOW...ALTHOUGH SOME OF THE SMALLER SCALE MODELS DID INDICATE A
FEW LIGHT FLURRIES OR SNOW SHOWERS. OTHERWISE...DRY CONDITIONS
SHOULD LINGER THROUGH WEDNESDAY MORNING...AS THE HIGH PRESSURE
SYSTEM SLOWLY EXITS TO EASTERN ONTARIO AND OVER JAMES BAY BY 00Z
THURSDAY.
WILL CONTINUE TO HEDGE THE FORECAST CLOSER TO THE ECMWF WITH THIS
PACKAGE UPDATE. ALTHOUGH IT IS A LITTLE WEAKER AND EASTWARD WITH
THE SURFACE LOW TO OUR SOUTH AND EAST DURING THE DAY THURSDAY...BOTH
THE GFS AND ECMWF HAVE THE SURFACE LOW OVER FAR EASTERN UPPER
MICHIGAN AT 18Z FRIDAY /ALTHOUGH THE GFS IS DEEPER WITH THE SYSTEM/.
PRECIPITATION TYPE AND AMOUNTS REMAIN A CONCERN...WITH RAIN MAINLY
CENTRAL AND EAST...CLOSER TO THE LOW. WEDNESDAY NIGHT STILL LOOKS
LIKE A POTENTIAL FOR FREEZING RAIN...WITH SURFACE TEMPERATURES OF
29-32F BETWEEN 01-11Z THURSDAY. WHILE THE TYPICAL ROADWAYS MAY STAY
WARM ENOUGH FOR WET CONDITIONS DUE TO LINGER SALT DEPOSITS ALREADY
ON THEM...AND BEING MORE WELL-TRAVELED. AS WE MOVE DEEPER INTO THE
SPRING SEASON IT BECOME INCREASINGLY DIFFICULT FOR ROADWAYS TO STAY
BELOW FREEZING FOR TOO LONG. STILL HAVE A GOOD CHANCE OF FREEZING
RAIN ACCUMULATING TO GENERALLY LESS THAN A TENTH OF AN INCH. KEPT
THE MENTION IN THE HWO AT THIS POINT. ALSO HAVE THE POTENTIAL FOR
2-4 INCHES OF HEAVY WET SNOW OVER THE HIGHER TERRAIN OF THE WEST
WEDNESDAY NIGHT...LINGERING INTO THURSDAY WITH A SMALL BREAK FIGURED
BEFORE WE COME UNDER THE INFLUENCE OF THE 500MB TROUGH AND COLDER
AIR PUSHING IN FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT.
NNE 850MB WINDS OF 30-50KT LOOK REALISTIC FROM 06-15Z
FRIDAY...BEFORE TURNING MORE NORTHERLY AS THE LOW PUSHES ACROSS
EASTERN UPPER MICHIGAN. INTRODUCED GALE FORCE VALUES TO PORTIONS OF
MAINLY CENTRAL LAKE SUPERIOR FRIDAY INTO FRIDAY EVENING...BUT WOULD
NOT BE SURPRISED IF WE NEED TO BUMP UP OUR FORECAST FOR THE NE WINDS
FUNNELING DOWN THE WESTERN HALF OF LAKE SUPERIOR EARLIER IN THE DAY.
THE WEST END OF THE CWA /GOGEBIC AND ONTONAGON COUNTIES/ WILL ALSO
HAVE THE BEST CHANCE OF LAKE EFFECT/LAKE ENHANCED SNOW
ACCUMULATIONS...WITH 850MB TEMPS GENERALLY COOLING BELOW -6C.
LIGHTER AMOUNTS ARE FIGURED EAST...WITH WARMER AIR WILL AROUND AND A
MIX OF RAIN OR SNOW POSSIBLE FAR EAST THROUGH THE DAY FRIDAY.
DRY WEATHER SHOULD BE THE RULE ONCE AGAIN STARTING SATURDAY AS HIGH
PRESSURE BUILDS IN AT THE SFC. HOWEVER WITH NW FLOW LINGERING ALOFT
AND N-NNW WINDS AT THE SURFACE...ALONG WITH 850MB TEMPS OF -11 TO
-14C...LINGERING SNOW SHOWERS WILL BE POSSIBLE EAST OF MARQUETTE
NEAR LAKE SUPERIOR INTO THE MID/LATE MORNING HOURS.
THERE ARE SIGNIFICANT TIMING DIFFERENCES WITH THE APPROACH OF THE
NEXT SYSTEM. THEY DO AGREE ON STRONG S WINDS AT 850MB...AGAIN
APPROACHING THE 40-55KT RANGE FROM MAINLY LATE SUNDAY AFTERNOON
THROUGH MONDAY MORNING...AS THE LLJ PUSHES W TO E ACROSS THE CWA.
THE MAIN ISSUE IS REGARDING THE TIMING OF THE NEXT SURGE OF
MOISTURE/PRECIPITATION...WHICH THE 15/12Z GFS IS MUCH MORE
PROGRESSIVE AND BRINGS IN MORNING TO THE WEST HALF. THIS IS APPROX 6
OR MORE HOURS FASTER THAN THE 15/06Z GFS RUN. THE 12Z ECMWF SHOWED A
SLOWER SOLUTION. GIVEN THE VARIABILITY SHOWN IN THE AVAILABLE
MODELS...IT SEEMS REASONABLE TO CONCENTRATE A BIT MORE ON THE NEAR
TERM...AND RUN WITH A CONTINUED CONSENSUS APPROACH AFTER 00Z MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 138 PM EDT MON APR 15 2013
ALTHOUGH MVFR CONDITIONS ARE POSSIBLE THIS AFTN AT IWD/CMX CLOSER TO
DEEPER MSTR ASSOCIATED WITH LO PRES IN MN MOVING INTO NW ONTARIO...
EXPECT PREDOMINANT VFR WX TO PREVAIL AT THE TAF SITES. DATYIME
HEATING/MIXING WL BRING GUSTY SW WINDS...WHICH WL SUBSIDE AT SUNSET
WITH SOME NOCTURNAL COOLING/STABILIZATION. APRCH OF LO PRES TROF/
SOMEWHAT DEEPER MSTR TNGT WL BRING A RETURN OF PREDOMINANT MVFR
CONDITIONS...ESPECIALLY AT CMX WITH MORE SIGNIFICANT UPSLOPE WIND
COMPONENT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT MON APR 15 2013
SHORT LIVED GALE EVENT WILL CONTINUE TO WIND DOWN EARLY THIS MORNING
ACROSS THE EAST HALF OF LAKE SUPERIOR AS THE LOW NEARS THE AREA AND
ALSO WEAKENS WHICH WILL WEAKEN THE PRESSURE GRADIENT. WINDS THEN
DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING OUT OF THE N
THURSDAY INTO FRIDAY WHEN GALES MAY BE POSSIBLE AGAIN AS ANOTHER
STRONG LATE SPRING SNOWSTORM AFFECTS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EDT MON APR 15 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 420 PM EDT MON APR 15 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR TROF
STRETCHING FM MN THRU THE PAC NW UPSTREAM OF UPR RDG OVER THE ERN
CONUS. SHRTWV THAT CAUSED WINTRY MIX OF PCPN SUN INTO THIS MRNG IS
LIFTING NEWD THRU MN ON THE ERN FLANK OF THE UPR TROF AXIS. DRY SLOT
ON THE ERN FLANK OF THIS DISTURBANCE HAS ADVECTED MUCH DRIER MID LVL
AIR OVER UPR MI WITH SW H7 WINDS UP TO 73 KTS AS SHOWN ON THE 12Z
GRB RAOB. SINCE WARM CONVEYOR BELT MSTR HAS ALSO SHIFTED TO THE E...
THE CWA IS PCPN FREE THIS AFTN. RETURN OF SUNSHINE UNDER THE DRY
SLOTTING OVER THE W AND CENTRAL HAS CAUSED TEMPS TO RECOVER TO MORE
SEASONABLE LVLS. OVER THE E...LO CLDS HAVE BEEN MORE PERSISTENT WITH
SSW LLVL FLOW OFF THE CHILLY LK MI WATERS AND LLVL MSTR SHOWN ON THE
12Z GRB RAOB. BKN SC HAS ALSO DVLPD OVER THE W AS DAYTIME HEATING
HAS DESTABILIZED LLVL LAPSE RATES WITH INFLUX OF LOWER H85 TEMPS AND
ARRIVAL OF MOISTER LLVL AIR DEPICTED ON THE 12Z MPX RAOB.
TNGT...SHRTWV/SFC LO IN MN ARE PROGGED TO SHIFT NEWD THRU NW
ONTARIO. ALTHOUGH SUPPORTING DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL
SLIDE TO THE NW OF UPR MI...THERE MAY BE ENUF MOISTENING OVER THE W
WITH THE SLOW ARRIVAL OF COLDER AIR TO JUSTIFY RETAINING FCST OF
SCHC POPS IN THAT AREA...ESPECIALLY OVERNGT WITH A WSHFT TO AN
UPSLOPE W COMPONENT COINCIDENT WITH LO PRES TROF PASSAGE TO THE S OF
LO MOVING THRU NW ONTARIO. ALTHOUGH THERE MAY BE MORE SC OVER THE CNTRL AS
WELL...THE TRANSITION TO A MORE W WIND SHOULD AID CLRG OVER THE E.
TUE...LO PRES TROF ON THE SW FLANK OF DEPARTING SHRTWV/SFC LO TOWARD
JAMES BAY WL CROSS UPR MI BY EARLY AFTN. ALTHOUGH THERE WL LIKELY BE
QUITE A BIT OF SC IN THE MOIST CYC W-SW SHIFTING NW FLOW...SHARP INVRN
NEAR H8 SHOWN ON FCST SDNGS IN THE ABSENCE OF ANY UPR SUPPORT WL
SQUASH POPS AWAY FM THE W...WHERE UPSLOPE FLOW MIGHT GENERATE A FEW
-SHSN IN THE MRNG. AS THE LLVL FLOW TRENDS MORE ACYC DURING THE AFTN
FOLLOWING THE TROF PASSAGE AND SE OF HI PRES BLDG TOWARD NW
ONTARIO...THE SC MAY TEND TO BREAK UP IN THE AFTN...ESPECIALLY
DOWNWIND OF LK SUP WITH SPRING STABILIZATION IN THE AFTN OFF THE
WATER. DEEP MIXING TO H8-85 WL SUPPORT MAX TEMPS APRCHG 50 OVER THE
SCENTRAL WITH DOWNSLOPE NW FLOW. AREAS NEAR LK SUP WL BE COOLER.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 459 AM EDT MON APR 15 2013
LARGER SCALE FEATURES AN UPPER TROUGH OVER UPPER LAKES EARLY THIS
WEEK WITH THE TROUGH MOVING INTO NORTHERN QUEBEC ON TUESDAY.
ASSOCIATED SURFACE LOW LIFTS TO SOUTH END OF JAMES BAY BY 12Z ON
TUESDAY AS MAIN COLD FRONT SLIDES EAST...FROM SOUTHERN QUEBEC INTO
THE MID MISSISSIPPI RIVER VALLEY.
WEAK SURFACE TROUGH MOVES ACROSS LAKE SUPERIOR AND UPPER MICHIGAN ON
TUESDAY BUT DRY AIR IN WAKE OF MAIN COLD FRONT RESULTS IN MINIMAL
CHANCES OF ANY PRECIPITATION. NORTH WIND OFF LK SUPERIOR WILL KEEP
TEMPS CHILLY AND THERE SHOULD BE BKN STRATOCU CLOUDS AROUND. QUIET
CONDITIONS STAY IN PLACE THROUGH WEDNESDAY AS HIGH PRESSURE MOVES BY
ACROSS NORTHERN ONTARIO. MID CLOUDS WILL BE ON THE INCREASE LATER
WEDNESDAY AHEAD OF DEVELOPING LOW PRESSURE SYSTEM OVER THE SOUTHERN
PLAINS. LAST 3 RUNS OF NAM HAVE TRENDED DRIER THROUGH 00Z THURSDAY.
00Z NAM HAS ONLY LGT QPF ALONG WI BORDER THROUGH 00Z THURSDAY...THEN
BRINGS HEAVIER QPF IN OVERNIGHT WEDNESDAY NIGHT. NAM SOUNDINGS SHOW
DRY LAYER FM H9-H7 LINGERING THROUGH THE DAY RESULTING IN DELAY OF
QPF INTO UPR MICHIGAN. ECMWF HAS BEEN CONSISTENT WITH HANDLING OF
THE SYSTEM AND MULTIPLE RUNS OF ECMWF SHOW QPF ARRIVING BY WEDNESDAY
AFTN...THOUGH LATEST ECMWF IS NOT AS BULLISH WITH QPF OVER FAR EAST
CWA THROUGH 00Z THURSDAY. NAM OVERALL APPEARS AT LEAST 6 HOURS
SLOWER WITH ARRIVAL OF LEAD SHORTWAVE/VORT MAX SLIDING OVER UPR
MICHIGAN/NORTHERN WI/NORTHERN LK MICHIGAN. 00Z GFS IN LINE WITH
ECMWF IDEA WITH TIMING OF SHORTWAVE AND ASSOCIATED QPF...THOUGH OVER
THE EAST IT IS ALSO A BIT SLOWER WITH ARRIVAL. SINCE THERE IS LARGE
SFC HIGH/DRY AIR FAIRLY CLOSE BY TO START DAY ON WEDNESDAY...THINK
SLOWER ARRIVAL OF QPF INTO EASTERN CWA HAS SOME MERIT. ADJUSTED
FORECAST ACCORDINGLY AND KEPT SLIGHTLY LOWER POPS INTO WEDNESDAY
EVENING OVER EAST AS WELL.
AS IT GOES WITH CURRENT SYSTEM...PTYPE WILL BE AN ISSUE WITH THIS
NEXT SYSTEM. PER FAVORED WPC/ECMWF IDEA...SFC-H85 LOW TROUGH AT
00Z THU WILL BE SET UP FROM MO INTO WESTERN WI. SFC FLOW WILL BE
FROM EAST...WHILE 925-850MB FLOW IS SE GOING TO SRLY. WARM AIR WILL
BE ON ITS WAY NORTH WEDNESDAY NIGHT AND THURSDAY. BASED ON 925-850MB
TEMPS AND 1000-850MB THICKNESSES IT APPEARS THAT FAR WEST/NORTHWEST
STAYS MAINLY IN THE FORM OF SNOW INTO THURSDAY WHILE CNTRL CWA WILL
BE MORE ON THE RAIN/SNOW EDGE. EASTERLY FLOW AT SFC AND SFC TEMPS
ONLY MARGINALLY ABOVE FREEZING ALONG WITH LIMITED WARM AIR ADVECTION
SFC-H9 POINT TO FREEZING RAIN POTENTIAL LATER WEDNESDAY NIGHT.
ALREADY MENTIONED HEAVY SNOW IN PREVIOUS HAZARDOUS WEATHER OUTLOOK.
WILL NOW ADD MENTION OF FZRA. SHOULD BE SUFFICIENTLY WARM ENOUGH FOR
JUST RAIN OVER SOUTH AND EAST CWA...THOUGH WITH INITIAL DYNAMIC
COOLING THERE MAY SOME SNOW MIXING IN WEDNESDAY EVENING OVER MUCH OF
CWA. ONLY PROBLEM IS BLYR MAY BE TOO WARM TO SUPPORT THAT AS TEMPS
ON WED AFTN MAY PUSH ABOVE 45 DEGREES BEFORE CLOUDS THICKEN. WILL
JUST USE LARGER SCALE THICKNESSES NOW AND KEEP IT ONLY RAIN FOR
SOUTH AND EAST.
GFS STARTS TO STRAY WITH HANDLING OF ENTIRE UPPER TROUGH AND SURFACE
LOWS THURSDAY NIGHT INTO FRIDAY. LAST TWO RUNS OF GFS INDICATE
STRONG SURFACE LOW DEVELOPING OVR THE CNTRL GREAT LAKES AND PRECIP
LINGERING OVER UPR MICHIGAN INTO FRIDAY NIGHT. ECMWF HAS SECONDARY
LOW PRESSURE AND MAYBE A THIRD ONE BUT IS NOT AS WRAPPED UP AS GFS.
DO THINK THERE IS NOW MORE OF A CHANCE OF SEEING LINGERING SNOW
SHOWERS DUE TO LAKE ENHANCEMENT THURSDAY NIGHT INTO FRIDAY WITH
SFC-H85 CYCLONIC FLOW AND SINCE H85 TEMPS ARE AOB -6C. TWEAKED POPS
UPWARD ON THURSDAY NIGHT...BUT THESE MAY NEED FURTHER INCREASING IF
TRENDS FROM 00Z ECMWF AND 18Z/00Z GFS CONTINUE.
ECMWF TRENDING SLOWER WITH LOW PRESSURE SYSTEM MOVING ACROSS LATE
NEXT WEEKEND. LOWERED CONSENSUS POPS TO JUST SLIGHT CHANCE FOR NEXT
SUNDAY. CONSENSUS OF MODELS KEEPS COOLER THAN AVERAGE TEMPS GOING
THROUGH NEXT WEEKEND. NO REASON TO DOUBT THIS IDEA SINCE LARGER
SCALE TROUGHING ONLY SLOWLY RELAXES THROUGH END OF EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 138 PM EDT MON APR 15 2013
ALTHOUGH MVFR CONDITIONS ARE POSSIBLE THIS AFTN AT IWD/CMX CLOSER TO
DEEPER MSTR ASSOCIATED WITH LO PRES IN MN MOVING INTO NW ONTARIO...
EXPECT PREDOMINANT VFR WX TO PREVAIL AT THE TAF SITES. DATYIME
HEATING/MIXING WL BRING GUSTY SW WINDS...WHICH WL SUBSIDE AT SUNSET
WITH SOME NOCTURNAL COOLING/STABILIZATION. APRCH OF LO PRES TROF/
SOMEWHAT DEEPER MSTR TNGT WL BRING A RETURN OF PREDOMINANT MVFR
CONDITIONS...ESPECIALLY AT CMX WITH MORE SIGNIFICANT UPSLOPE WIND
COMPONENT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 459 AM EDT MON APR 15 2013
SHORT LIVED GALE EVENT WILL CONTINUE TO WIND DOWN EARLY THIS MORNING
ACROSS THE EAST HALF OF LAKE SUPERIOR AS THE LOW NEARS THE AREA AND
ALSO WEAKENS WHICH WILL WEAKEN THE PRESSURE GRADIENT. WINDS THEN
DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING OUT OF THE N
THURSDAY INTO FRIDAY WHEN GALES MAY BE POSSIBLE AGAIN AS ANOTHER
STRONG LATE SPRING SNOWSTORM AFFECTS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...07
AREA FORECAST DISCUSSION
NWS HASTINGS NE
103 PM CDT MON APR 15 2013
.UPDATE...
ISSUED AT 103 PM CDT MON APR 15 2013
CONFIDENCE HAS DIMINISHED IN SHORT-TERM CLOUD COVER AND THIS HAS
TEMP IMPLICATIONS AS WELL. WE/VE NOTED RAPID CLEARING FROM OGA-
TIF-ONL. THE ONLY MODEL ONTO THIS IS THE HRRR AND IT INDICATES
COMPLETELY CLEARING. WE HAVE NO CHOICE BUT TO MAKE ADJUSTMENTS BUT
THE MAGNITUDE AND EXTENT ARE NOT EASY.
UPDATE ISSUED AT 955 AM CDT MON APR 15 2013
A REINFORCING SHOT OF COLD AIR MOVED THRU THE FCST AREA THIS MRNG.
THE FRONTAL INVERSION WAS NEAR 2700 FT ON THE 12Z LBF/OAX
SOUNDINGS. DIFFERENTIAL ADVECTION WAS OCCURRING ABOVE AND BELOW
THE FRONTAL ZONE...WITH WAA IN THE MID-LVLS AHEAD OF A WEAK H7 LOW
OVER CO. THIS WAS THE CAUSE FOR THE RETURNS YOU SEE ON RADAR. ONLY
A FEW FLURRIES MADE IT TO THE GROUND AS THE LOW-LEVELS ARE DRY.
CIGS ARE MOSTLY 8-10K FT.
AS FOR THE FCST EXPECT A MAINLY OVC DAY. SOME BREAKS OR THIN SPOTS
ARE LIKELY WELL SE OF THE TRI-CITIES. SATL SHOWS CLEARING OVER NW
KS AND IT APPEARS TO BE ADVANCING NE. RAP MODEL DOES HAVE THE
TREND SO WILL UPDATE THE FCST TO SHOW SOME IMPROVEMENT WITH
DECREASING CLOUDS S OF HWY 6. WITH THIS IN MIND WILL LEAVE HIGH
TEMPS IN THE MID 50S DOWN THERE AS WELL. WITH OVC EXPECTED TO
REMAIN ALONG AND N OF HWY 6...WILL BE LOWERING HIGH TEMPS 3-6F FOR
OUR NRN COUNTIES.
UPDATE ISSUED AT 825 AM CDT MON APR 15 2013
SENT AN UPDATE TO BETTER REFLECT CURRENT CONDS. THIS INCLUDED
TAKING SKY UP TO OVC. A NOWCAST WAS ISSUED AT 815 AM AND HAVE
INCLUDED SCT FLURRIES IN THE FCST FROM THE TRI-CITIES N AND E.
REFLECTIVITY IS MOVING E AROUND 55 KTS. NEW ECHOES ARE DEVELOPING
W OF THE FCST AREA SO WILL REEVALUATE AS I GET INTO THE SWING OF
THINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON APR 15 2013
TEMPERATURES WILL CONTINUE THEIR DOWNWARD TREND TODAY AS COOLER AIR
CONTINUES TO FILTER IN ACROSS THE REGION BEHIND A SECONDARY COLD
FRONT WHICH SAGGED SOUTHWARD OVERNIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL ANOTHER 10 DEGREES OR SO FROM SUNDAYS
HIGHS.
WHILE SOME CLOUDS ARE STARTING TO FILTER IN ACROSS THE LOCAL
AREA FROM THE WEST THIS MORNING...EXPECT CLOUD COVER TO INCREASE
FURTHER THROUGHOUT THE DAY AS THE NEXT UPPER LEVEL DISTURBANCE
CROSSES THE INTERMOUNTAIN WEST. WHILE BOTH THE 00Z WRF AND 06Z NAM
ARE TRYING TO DEVELOP A BAND OF LIGHT PRECIP ACROSS MUCH OF THE
FORECAST AREA OVERNIGHT TONIGHT...MODELED SOUNDINGS INDICATE A
SIGNIFICANT SPREAD BETWEEN SURFACE TEMPS AND DEWPOINTS THROUGH AT
LEAST THE FIRST HALF OF THE NIGHT...WITH WESTERN AREAS BEGINNING
TO SATURATE AS WE ENTER THE EARLY MORNING HOURS TUESDAY. AS A
RESULT...WENT AHEAD AN TRIMMED BACK POPS A BIT DURING THE EVENING
AND OVERNIGHT HOURS...CONTINUING WITH ONLY SMALL CHANCES FOR SOME
LIGHT RAIN OR SNOW IN AN AREA OF ISENTROPIC LIFT AHEAD OF THIS
NEXT DISTURBANCE. EVEN IF PRECIPITATION IS REALIZED...DO NOT
EXPECT MUCH IN THE WAY OF ACCUMULATION...WITH A FEW HUNDREDTHS OF
LIQUID PRECIP EQUIVALENT AT MOST.
IN ADDITION TO TWEAKING DOWN PRECIP CHANCES SOME OVERNIGHT
TONIGHT...ALSO TWEAKED DOWN LOW TEMPERATURES A BIT TUESDAY MORNING TO
BRING CLOSER TO LATEST GUIDANCE AND TO ACCOUNT FOR THIS COOLER
AIRMASS. OTHERWISE...ONLY A FEW MINOR TWEAKS TO THE WIND/DEWPOINT
GRIDS WERE NECESSARY THIS MORNING...WITH NO SIGNIFICANT WEATHER
IMPACTS EXPECTED THROUGH THE SHORT TERM PERIODS AT THIS TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON APR 15 2013
MAIN FORECAST CONCERNS LIE WITH MID WEEK PRECIPITATION CHANCES...AND
PLENTY OF DETAILS TO IRON OUT BETWEEN MODELS KEEPING CONFIDENCE ON
THE LOWER SIDE.
STARTING OFF THE LONG TERM PERIOD ON TUESDAY...OUTSIDE SOME
LINGERING PRECIPITATION CHANCES DURING THE MORNING ALONG A NARROW
BAND OF MID LEVEL FRONTOGENETICAL FORCING AND ISENTROPIC LIFT...THE
FORECAST IS QUIET...THOUGH WILL HAVE KEEP AN EYE ON THE POTENTIAL
FOR DRIZZLE ACROSS THE SRN PORTIONS OF THE CWA. THE CWA IS SITTING
UNDER SOUTHWESTERLY FLOW IN THE UPPER LEVELS...AHEAD OF ANOTHER
SYSTEM OVER THE ROCKIES...WHICH THROUGH THE DAYTIME HOURS DIGS
FURTHER SOUTH INTO THE ROCKIES. EXPECTING TO SEE EASTERLY WINDS
ACROSS THE CWA AS SFC LOW PRESSURE ORGANIZES OVER THE FOUR CORNERS
REGION. ALONG WITH THE EXPECTED CLOUD COVER AND COOLER AIR MASS IN
PLACE...THINKING HIGH TEMPERATURES IN THE MID 40S LOOKS REASONABLE.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT STILL LOOKING LIKE THE PRIMARY
ACTIVE TIME FRAME OF THE EXTENDED PERIOD...AND EVEN WITH THE EVENT
BEING THIS CLOSE...STILL PLENTY OF VARIATIONS BETWEEN MODELS AND
DETAILS TO IRON OUT. TUESDAY NIGHT...MAIN CONCERN IS PRECIPITATION
POTENTIAL INCREASING...WILL BEGIN TO SEE INCREASING LARGER SCALE
LIFT ACROSS THE REGION AS THE MAIN SYSTEM SHIFT EAST ACROSS THE
ROCKIES...BUT MODELS ARE SHOWING A SRLY LLJ JET NOSING RIGHT INTO
THE CWA. THERE ARE SOME DIFFERENCES BETWEEN MODELS WITH THE
STRENGTH OF THE LLJ...AND WITH THE AMOUNT OF ELEVATED INSTABILITY
AVAILABLE...BUT MENTION OF ISOLATED THUNDER REMAINS IN THE FORECAST
ACROSS SRN PORTIONS OF THE CWA. AS MENTIONED BY PREVIOUS
FORECAST...SOME MODELS CAME IN WARMER AND HAVE REMAINED THAT
WAY...BUT NOT ALL MODELS HAVE. THE ECMWF REMAINS ON THE NOTABLY
COOLER SIDE OF THINGS...5+ DEGREES COOLER IN SOME LOCATIONS. THIS
SOLUTION WOULD BRING A COMPLETE SWITCH OVER TO SNOW TUESDAY NIGHT
FOR A GOOD PORTION OF THE CWA...BUT WITH LITTLE SUPPORT FROM OTHER
MODELS...WILL BE KEEPING PRECIP TYPE AS MAINLY LIQUID WITH A RA/SN
MIX POSSIBLE IN THE NWRN CWA. THIS COOLER ECMWF SOLUTION CONTINUES
THROUGHOUT THE ENTIRE EVENT.
WEDNESDAY...DIDNT MAKE SIGNIFICANT CHANGES TO THE POPS...BUT AM
CONCERNED ABOUT HOW MUCH PRECIPITATION IS ACTUALLY GOING TO BE GOING
ON ONCE THE ACTIVITY FROM OVERNIGHT SLIDES OUT OF THE AREA. MODELS
GENERALLY SHOWING THE SAME BASIC STORY WITH THE MID/UPPER LEVEL
PATTERN THROUGH THE DAYTIME HOURS...CONTINUING ITS EASTWARD SLIDE
AND BY 00Z HAVING AN ELONGATED 700MB LOW ORIENTATED IN A SW/NE LINE
ACROSS WRN PORTIONS OF NEB/KS...WITH A MORE OPEN PATTERN AT 500MB.
AM A LITTLE CONCERNED ABOUT THE 00/06Z NAM RUNS...WHICH BOTH SHOWED
A MORE PRONOUNCED DRY SLOT/BREAK IN PRECIP DURING THE AFTERNOON...BUT
IT IS ALSO MORE ORGANIZED IN THE MID/UPPER LEVELS AND HAS THE LOW
FURTHER N/NE THAN OTHER SOLUTIONS. NOT PUTTING A LOT OF WEIGHT IN
IT...BUT IS SOMETHING TO KEEP AN EYE ON. ANOTHER QUESTION IS WHERE
THE ACCOMPANYING SFC COLD FRONT ENDS UP...AS THIS FRONT WILL PROVIDE
A FOCUS FOR THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON/EVENING
HOURS AS LARGE SCALE LIFT CONTINUES TO INCREASE WITH THE APPROACHING
SYSTEM. THIS TIME ITS THE GFS THAT IS CONCERNING...AS ITS PLACEMENT
OF THE SFC LOW AND FRONTAL BOUNDARY IS FURTHER NORTH THAN THE OTHER
SOLUTIONS...AND IF IT ENDS UP VERIFYING...OUR CWA /ESP THE SRN
PORTIONS/ WOULD BE LOOKING AT A BETTER POTENTIAL FOR
THUNDERSTORMS..INCLUDING SEVERE ONES. AT THIS POINT AM KEEPING THE
FORECAST TRENDED TOWARD THE FURTHER SOUTHWARD PLACEMENT OF THE SFC
FRONT AND ONLY AN ISOLATED MENTION OF THUNDER.
WITH ALL THE VARIATIONS BETWEEN MODELS WITH THE PRECIPITATION
THROUGH THE DAY AND SFC FRONT PLACEMENT...THERE IS A POTENTIAL FOR A
BUST ON AFTERNOON TEMPS...ESP ACROSS THE SOUTHEASTERN HALF. SOME
GUIDANCE/MODELS HAVE HIGHS IN THE 50S/NEAR 60 DEGREES IN THOSE
AREAS...DID BUMP HIGHS A COUPLE DEGREES...BUT WITH SOME MODELS
REMAINING ON THE COOLER SIDE DIDNT WANT TO BUY FULLY INTO THE WARMER
TEMPS QUITE YET.
WEDNESDAY NIGHT/THURSDAY...WHATEVER INSTABILITY THAT IS IN PLACE
OVER THE AREA IS EXPECTED TO QUICKLY FOCUS FURTHER SOUTHEAST OF THE
CWA WEDNESDAY NIGHT...AS THE AXIS OF THE MID/UPPER LEVEL SYSTEM
STARTS TO MOVE FURTHER INTO THE PLAINS...STILL PROVIDING PLENTY OF
LIFT ACROSS THE AREA...BUT BETTER PRECIPITATION CHANCES ARE EXPECTED
TO START SETTING UP OVER ERN PORTIONS OF THE CWA. DID BUMP UP POPS
A TOUCH DURING THE DAY THURSDAY...WITH BETTER AGREEMENT SHOWING THE
SYSTEM A LITTLE SLOWER TO MOVE EAST. MODEL DIFFERENCES WITH THE
THERMAL PROFILE REMAIN IN PLACE...LEAVING SOME QUESTION WITH HOW
QUICKLY A RA/SN MIX OR JUST SN BUILD IN FROM THE WEST. STILL
UNCERTAINTIES WITH ACCUMULATIONS BECAUSE OF THIS ALONG WITH THE
DIFFERENCES IN MODEL QPF ACROSS THE CWA /THE NAM AND SREF HAVE VERY
LITTLE/...BUT THE NORTHWESTERN HALF/THIRD OF THE CWA REMAINS THE
AREA WITH THE BEST POTENTIAL FOR ACCUMULATING SNOWFALL.
LOOKING AT THE FORECAST FOR THURSDAY NIGHT THROUGH
SUNDAY...NORTHWESTERLY FLOW SETS UP IN THE UPPER LEVELS AS THIS MID
WEEK SYSTEM SLIDES FURTHER EAST AND WITH RIDGING OFF THE WEST
COAST. THE FORECAST REMAINS DRY...WITH THE ONE EXCEPTION BEING ON
SUNDAY...WITH MODELS CONTINUING TO SHOW A WEAK UPPER LEVEL
DISTURBANCE SLIDING THROUGH THE REGION. SHOULD BEGIN TO SEE A
REBOUND IN TEMPERATURES...AS THE COLDER AIR SLIDES EAST ALONG WITH
THE MAIN SYSTEM...BUT AT THIS POINT NOT LOOKING AT A SIGNIFICANT WARM
UP...JUST ENOUGH OF ONE TO GET US AT LEAST BACK CLOSER TO AVERAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM CDT MON APR 15 2013
THIS AFTN: VFR MID-LEVEL CIGS. THERE IS A CHANCE CIGS COULD BECOME
SCT LATE. NW WINDS 10-15 KTS WILL BECOME N.
TNGT: VFR MID-LEVEL CIGS MAY DESCEND TO AROUND 5K FT. THERE IS A
VERY LOW PROB FOR A TOUCH OF MVFR -SN. CONFIDENCE IS NOT HIGH ENUF
TO INCLUDE IN THE TAF. N WINDS AROUND 10 KTS.
TUE THRU 18Z: VFR MID-LEVEL CIGS CONTINUE. NE WINDS 10-15 KTS.
CIG CONFIDENCE: AVERAGE
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
WX CONFIDENCE: AVERAGE
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1223 PM CDT MON APR 15 2013
.UPDATE...
UPDATED TO ADJUST HIGHS UP A FEW DEGREES. WITH AVIATION DISCUSSION
FOLLOWING AS WELL.
&&
.DISCUSSION...
TEMPERATURES CONTINUE TO RUN AT OR A LITTLE ABOVE WHERE THEY WERE
YESTERDAY AT ANY WEST CENTRAL TEXAS LOCATIONS. LATEST RUC
FORECASTING A LITTLE WARMER AS WELL. USED THE RUC AS A STARTING
POINT AND BOOSTED TEMPS.
&&
.AVIATION...
VFR CONDITIONS TO PREVAIL ACROSS WEST CENTRAL TEXAS TERMINALS WELL
INTO TONIGHT...AS DRY SOUTHWEST TO WEST WINDS PREVAIL. MODELS NOT
FORECASTING MUCH IN THE WAY OF STRATUS RETURN TUESDAY
MORNING...EVEN NEAR JUNCTION AND BRADY...KJCT AND KBBD. BUT BOTH
PERSISTENCE AND CLIMATOLOGY SUGGESTS THERE IS A DECENT CHANCE.
WILL LEAVE IT IN THE FORECAST FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 617 AM CDT MON APR 15 2013/
DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION...
MVFR STRATUS WAS APPROACHING KJCT AT 11Z...AS LOW LEVEL MOISTURE
RETURNED FROM THE EAST. STRATUS MAY ALSO AFFECT KBBD AFTER
13Z. STRATUS CIGS SHOULD SCATTER OUT BY MID MORNING AS LOW LEVEL
MOISTURE WAS SHALLOW. MVFR STRATUS WILL RETURN TONIGHT AT KJCT...
KBBD LATE TONIGHT. STRATUS MAY POSSIBLY AFFECT KSOA...BUT WILL NOT
INCLUDE AT THIS TIME AS CONFIDENCE IS LOWER FARTHER WEST.
PREV DISCUSSION... /ISSUED 420 AM CDT MON APR 15 2013/
SHORT TERM...
A WEAK COLD FRONT JUST NORTH OF HASKELL AND THROCKMORTON COUNTIES
THIS MORNING...IS INDICATED TO WASH OUT AND MOVE BACK NORTH WITH
SURFACE HEATING AND MIXING MIDDAY. LOW LEVEL MOISTURE WILL BE
RETURNING FROM THE EAST...AND A DRY LINE SHOULD SET UP THIS
AFTERNOON...FROM JUST EAST OF THROCKMORTON COUNTY TO CROSS PLAINS...
BRADY AND JUNCTION. WHILE THERE IS AN OUTSIDE CHANCE OF A
THUNDERSTORM DEVELOPING IN EASTERN THROCKMORTON COUNTY...ACTIVITY
SHOULD BE SPARSE IF IT OCCURS AND MOVE QUICKLY EAST.
TEMPERATURES TODAY WILL BE WARM...SIMILAR TO YESTERDAY...WITH
SOUTHWEST WINDS BRINGING IN DRY DESERT AIR TO THE WEST OF THE DRY
LINE. WINDS WILL BE WEAKER HOWEVER...KEEPING CONDITIONS BELOW RED
FLAG WARNING CRITERIA FOR FIRE WEATHER.
04
THE HEADLINE FOR THE LATTER PART OF THE SHORT TERM REMAINS
CENTERED ON RAIN CHANCES WITH THIS NEXT COLD FRONT. THE GFS AND
ECMWF ARE NOT IN VERY GOOD AGREEMENT REGARDING THE TIMING OF THE
FRONT WEDNESDAY NIGHT. SO...I DECIDED TO GO WITH A BLEND BETWEEN
WHAT WE HAD IN OUR WIND GRIDS FOR WEDNESDAY NIGHT AND A COMPROMISE
WITH THE GENERAL CONSENSUS FROM OUR NEIGHBORING OFFICES. AS FOR
RAIN CHANCES WEDNESDAY AND WEDNESDAY NIGHT...THE BEST CHANCES
STILL LOOK BEST FOR WEDNESDAY NIGHT. A SURFACE DRYLINE WILL MIX
EAST ACROSS OUR COUNTIES ON WEDNESDAY. THIS BOUNDARY AND THE COLD
FRONT MAY MERGE WEDNESDAY EVENING AND CREATE A FOCUS FOR
THUNDERSTORM DEVELOP. MY CONFIDENCE AS TO WHERE THESE TWO
BOUNDARIES MAY MERGE REMAINS LOW AT THIS TIME...MAINLY GIVEN THE
INCONSISTENCIES AMONG THE WIND FIELD OF THE THE MODELS. SO...I
DECIDED TO LEAVE THE POPS UNCHANGED FOR WEDNESDAY AND WEDNESDAY
NIGHT...EVEN THOUGH THE LATEST MEX MOS GUIDANCE IS PRESENTING 50
POPS FOR WEDNESDAY NIGHT FOR OUR THREE VERIFICATION LOCATIONS.
AS FOR TEMPERATURES FOR THE REMAINDER OF THE SHORT
TERM...AFTERNOON HIGHS TUESDAY WILL BE WELL ABOVE SEASONAL
NORMALS...WITH MUCH COOLER HIGHS FOR WEDNESDAY. THE LATEST MEX MOS
GUIDANCE PRESENTED NUMBERS FOR LOWS WEDNESDAY NIGHT MUCH WARMER
THAN WE HAD IN OUR PREVIOUS FORECAST PACKAGE. WITH MY CONFIDENCE
NOT VERY HIGH REGARDING THE TIMING OF THE FRONT WEDNESDAY
NIGHT...I DECIDED TO NOT INCREASE OUR LOWS FOR WEDNESDAY NIGHT
MORE THAN ONE DEGREE OVER WHAT WE HAD IN OUR PREVIOUS PACKAGE.
HUBER
LONG TERM...
THE LONG TERM...INTO NEXT SUNDAY...LOOKS DRY. COOLER TEMPERATURES
WILL PREVAIL THROUGH THE END OF THIS WEEK...BEFORE RETURN
SOUTHERLY LOW-LEVEL FLOW INITIATES A WARMING REBOUND FOR NEXT
WEEKEND. THE GFS DOES INDICATE THE POSSIBILITY OF ANOTHER COLD
FRONT NEXT SUNDAY. HOWEVER...I DECIDED NOT TO GO WITH THAT
SOLUTION THAT FAR IN ADVANCE. I WILL CONTINUE SOUTH SURFACE WINDS
FOR NEXT SUNDAY...WITH AFTERNOON HIGHS MAINLY IN THE 75 TO 80
RANGE.
HUBER
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED ACROSS MUCH OF WEST
CENTRAL TEXAS THIS AFTERNOON...AS A DRYLINE DEVELOPS FROM NEAR
BRECKENRIDGE TO CROSS PLAINS AND JUNCTION. THE DRYLINE WILL BE
FARTHER WEST TUESDAY AFTERNOON...GENERALLY ALONG AND WEST OF AN
OZONA TO SWEETWATER LINE. ON WEDNESDAY...THE DRYLINE SHOULD SET
UP FARTHER EAST...ALONG AND WEST OF A SONORA...SAN
ANGELO...ABILENE...HASKELL LINE. WHILE RH VALUES WILL FALL BELOW
20 PERCENT WEST OF THE DRYLINE...SOUTHWEST WINDS SHOULD REMAIN
BELOW 20 MPH...KEEPING CONDITIONS FROM BECOMING CRITICAL.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 96 63 90 67 87 / 10 10 10 10 30
SAN ANGELO 96 64 94 72 88 / 5 5 5 10 20
JUNCTION 97 64 91 71 89 / 5 5 5 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
342 PM CDT MON APR 15 2013
.VERY SHORT TERM...TONIGHT AND TUESDAY.
TONIGHT - CONFIDENCE...MEDIUM
PER WATER VAPOR STRONG SOUTHWEST UPPER JET ROUNDING BASE OF TROUGH
NRN MN CIRCULATION CENTER. MODELS ALSO SHOWING DECENT 850/700
MILLIBAR FRONTOGENETICAL FORCING ACROSS PORTIONS OF SRN WI. RAIN
AREA ALREADY WORKING INTO SRN WI. EXPECTED TO AFFECT MUCH SRN WI
INTO THE EVENING HOURS. COMBO OF HRRR AND SPC WRF SUGGESTS BULK OF
PRECIP WILL BE AFFECTING SE 1/2 OF THE CWA DURING THE EVENING HOURS.
TUESDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE GRADUALLY BUILDS IN. MODELS HAVE TRENDED THE QPF
FURTHER SOUTH. 12Z ECMWF DOES HAVE LIGHT QPF IN THE FAR SOUTH DURING
THE AFTERNOON SO HAVE RETAINED A SMALL POP BUT CONFIDENCE NOT GREAT.
THERE IS AN INDICATION OF AN INVERTED TROUGH AND POSSIBLY SOME RIGHT
REAR DIVERGENCE OF JET CORE TO OUR NORTH. SOUNDINGS SHOW LOW LEVELS
BELOW 5K FEET DRY BUT MID LEVEL SATURATION WITH OMEGA WITH SOME
PROGGD FRONTOGENETICAL FORCING IN THE 700-500 MILLIBAR LAYER.
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
12Z NAM BRINGS QPF INTO THE FORECAST AREA WITH ISENTROPIC
LIFT/850-700 MB FRONTOGENESIS/850 MB CONVERGENCE AS IT LIFTS 850/700
MB BAROCLINIC ZONES FARTHER NORTH THAN OTHER MODELS. 12Z ECMWF
BRINGS THE PCPN IN TUESDAY AFTERNOON THEN EAST IN THE EVENING...BUT
THE 850MB CONVERGENCE IS BETTER AFTER 06Z WEDNESDAY. IN SPITE OF
RELATIVELY DRY EAST FLOW...WILL KEEP CHANCE POPS IN THE FAR
SOUTH.
WEDNESDAY THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM TO
HIGH.
ELONGATED TROUGH OF SURFACE LOW PRESSURE...WITH MODELS SHOWING TWO
DISTINCT CENTERS...WILL LIFT INTO THE REGION AHEAD OF DEEP LONG WAVE
TROUGH AND THEN CONSOLIDATE OVER THE WESTERN GREAT LAKES. COPIOUS
AMOUNTS OF MOISTURE STREAMING INTO THE REGION WILL PRODUCE PERIODS
OF MODERATE TO HEAVY RAIN.
SOME TRACK LOCATION DIFFERENCES THAT IMPACT THE AMOUNT OF
INSTABILITY AND AREAL EXTENT OF THUNDERSTORMS...BUT CONSENSUS
FORECAST QPF OF 1.6 TO NEARLY 3 INCHES OF RAIN LOOKS TO OCCUR WITH
ONLY ISOLATED THUNDERSTORMS...WITH HIGHER AMOUNTS IF THUNDER BECOMES
MORE WIDESPREAD. HAVE ISSUED AN ESF TO HIGHLIGHT RISK OF INCREASED
FLOODING ACROSS THE REGION...WITH SATURATED GROUND UNABLE TO HOLD
MUCH ADDITIONAL RAINFALL AND MANY RIVERS ALREADY IN OR NEAR
FLOOD.
COLDER AIR WRAPPING IN BEHIND THE LOW WILL BRING A MIX OF RAIN AND
SNOW AFTER MIDNIGHT THURSDAY NIGHT...WITH ALL SNOW EXPECTED
NORTHWEST OF MADISON BY 12Z FRIDAY. BETTER DEFORMATION TO THE
NORTHWEST OF THE FORECAST AREA AND LIGHT QPF AMOUNTS AS TEMPERATURES
COOL SO ONLY MINOR ACCUMULATIONS EXPECTED.
NOT MUCH OF A CHANGE IN TEMPERATURES BETWEEN HIGHS WEDNESDAY AND
OVERNIGHT LOWS WITH EXPECTED NON-DIURNAL TREND. HIGHS NEAR 60 IN THE
FAR SE...THOUGH WARMER GFS MOS GUIDANCE IS PUSHING NEAR 70 IN THE
SOUTH.
.LONG TERM...FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE LOW TO
MEDIUM.
KEEPING CHANCE POPS FOR FRIDAY AS REGION REMAINS UNDER THE CYCLONIC
FLOW OF 500 MB TROUGH OVER THE CENTRAL U.S. AT START OF THE
PERIOD...WITH DRY WEATHER FROM OVERNIGHT FRIDAY THROUGH SATURDAY
NIGHT IN NW FLOW AS THE TROUGH SLOWLY PUSHES EAST. ANOTHER
WAVE COMES ASHORE IN THE PACIFIC NW FRIDAY AFTERNOON...REACHING THE
CENTRAL/SRN PLAINS BY SUNDAY MORNING....WHILE ANOTHER WAVE TRACKS
ALONG THE US/CANADIAN BORDER RIGHT BEHIND. THIS BRINGS THE CHANCE
FOR WET WEATHER BACK INTO THE FORECAST SUNDAY THROUGH THE REST OF
THE EXTENDED. BELOW NORMAL TEMPS FRIDAY AND SATURDAY WARM TO NEAR
NORMAL LEVELS SUNDAY AND MONDAY.
&&
.AVIATION/00Z TAFS/...UPPER JET AND LOWER LEVEL FRONTOGENETICALLY
INDUCED AREA OF RAIN TO MOVE THROUGH SOUTHERN WI THIS EVENING. MVFR
CEILINGS/VSBYS POSSIBLE. SOUNDINGS SHOW INITIALLY DRY LAYER IN THE
LOW LEVELS...THIS PROGGD TO MOISTEN UP. WILL GO WITH A MID DECK FOR
TUESDAY WITH LOWER LEVELS FAIRLY DRY. AFTERNOON SHOWERS POSSIBLE IN
FAR SRN WI BUT CONFIDENCE TOO LOW FOR INCLUSION IN TAFS.
&&
.MARINE...SOUTHWEST WINDS STILL GUSTING OVER CRITERIA SO WILL RETAIN
HEADLINE THROUGH 7 PM EXPIRATION. GRADIENT SLACKENS UP TONIGHT. HIGH
GRADUALLY BUILDS IN TUESDAY. WINDS GO NORTHEAST BUT NOT HIGH ENOUGH
TO WARRANT SMALL CRAFT CONCERNS AT THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...COLLAR
TUESDAY NIGHT THROUGH MONDAY...REM